U.S. patent application number 10/783396 was filed with the patent office on 2005-01-27 for method for making a cushion.
Invention is credited to Pearce, Terry V., Pearce, Tony M..
Application Number | 20050017396 10/783396 |
Document ID | / |
Family ID | 35542271 |
Filed Date | 2005-01-27 |
United States Patent
Application |
20050017396 |
Kind Code |
A1 |
Pearce, Tony M. ; et
al. |
January 27, 2005 |
Method for making a cushion
Abstract
A method for making a cushioning element including forcing
molten gel through an extrusion die, and cutting the gel as it
exits the die.
Inventors: |
Pearce, Tony M.; (Alpine,
UT) ; Pearce, Terry V.; (Alpine, UT) |
Correspondence
Address: |
Daniel P. McCarthy
Parsons Behle & Latimer
201 South Main Street, Suite 1800
P.O. Box 45898
Salt Lake City
UT
84111
US
|
Family ID: |
35542271 |
Appl. No.: |
10/783396 |
Filed: |
February 20, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10783396 |
Feb 20, 2004 |
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10059101 |
Nov 8, 2001 |
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10059101 |
Nov 8, 2001 |
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09303919 |
May 3, 1999 |
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6173575 |
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09303919 |
May 3, 1999 |
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08968750 |
Aug 13, 1997 |
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6026527 |
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08968750 |
Aug 13, 1997 |
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08601374 |
Feb 14, 1996 |
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5749111 |
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10783396 |
Feb 20, 2004 |
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10059101 |
Nov 8, 2001 |
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10059101 |
Nov 8, 2001 |
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09932393 |
Aug 17, 2001 |
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09932393 |
Aug 17, 2001 |
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09303979 |
May 3, 1999 |
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6413458 |
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Current U.S.
Class: |
264/148 ;
264/211.13 |
Current CPC
Class: |
A47C 7/021 20130101;
B29C 48/08 20190201; Y10S 5/948 20130101; B29L 2031/60 20130101;
B29K 2105/04 20130101; B29C 48/919 20190201; C08K 5/01 20130101;
C08K 5/0016 20130101; A47C 27/15 20130101; B29C 48/11 20190201;
B29C 48/9135 20190201; A47C 4/54 20130101; Y10S 5/953 20130101;
B29C 44/50 20130101; B29C 44/583 20130101; Y10S 5/909 20130101;
C08L 51/006 20130101; A43B 13/04 20130101; Y10T 428/24322 20150115;
Y10T 428/24331 20150115; B29C 2793/009 20130101; C08L 53/025
20130101; A47C 27/144 20130101; B29C 48/022 20190201; A47C 27/085
20130101; C08K 5/0016 20130101; C08L 53/02 20130101; C08K 5/01
20130101; C08L 53/02 20130101; C08L 51/006 20130101; C08L 2666/02
20130101; C08L 53/025 20130101; C08L 2666/02 20130101 |
Class at
Publication: |
264/148 ;
264/211.13 |
International
Class: |
B29C 047/00 |
Claims
What is claimed is:
1. A method for producing a cushioning element comprising the steps
of: (a) forcing molten gel into and through an extrusion die
wherein said extrusion die includes forming rods, an aperture and
an aperture periphery; (i) where said forming rods are within said
aperture and where said forming rods have an appearance similar to
that of the desired cushioning element except that portions of said
extrusion die that are solid will be represented by air in the
finished cushioning element and portions of said extrusion die that
are unobstructed will be represented by solidified gel in the
finished cushioning element; (ii) where the spacing of said forming
rods approximates the spacing of columns in the finished cushioning
element and the shape and size of said aperture periphery
approximates the shape and size of the desired cushioning element;
(b) cutting said gel as it leaves said extrusion die; and (c)
allowing said cut gel to cool in a cooling medium in order to
solidify said gel and thus form a cushioning element; wherein said
extrusion die is configured to produce a cushioning element having
a plurality of buckling columns formed in said solidified gel.
2. The method for producing a cushioning element as recited in
claim 1, wherein a cross section of at least one of said columns
taken orthogonal to said longitudinal axis of said column has a
shape selected from the group consisting of triangular, square,
rectangular, pentagonal, heptagonal, octagonal, round, oval, and
n-sided polygonal where n is an integer.
3. The method for producing a cushioning element as recited in
claim 1, wherein said molten gel includes elastomer gel
pre-compounded at a temperature of about 470 degrees Fahrenheit and
said forcing of said molten gel through said extrusion die is at
about 425 degrees Fahrenheit.
4. The method for producing a cushioning element as recited in
claim 3, wherein said pre-compounding and said forcing is done with
an extruder screw.
5. The method for producing a cushioning element as recited in
claim 1, wherein pressure in said extrusion die is from 200 to 4000
pounds per square inch.
6. The method for producing a cushioning element as recited in
claim 1, wherein said cooling medium is water.
7. The method for producing a cushioning element as recited in
claim 6, wherein the direction of said extrusion is upward into
said water.
8. The method for producing a cushioning element as recited in
claim 6, wherein the direction of said extrusion is downward into
said water.
9. A cushioning element made according to the method of claim 1,
the cushioning element comprising: (a) a quantity of said
solidified gel formed to have a top, a bottom, and an outer
periphery, said solidified gel being compressible so that it will
deform under the compressive force of a cushioned object, (b) the
cushioning element being adapted to have a cushioned object placed
in contact with said top; wherein each of said column ends is
positioned at two different points of said column axis; (c) at
least one of said columns being positioned within said solidified
gel such that said column axis is positioned generally parallel to
the direction of a compressive force exerted on the cushioning
element by a cushioned object in contact with said solidified gel;
and (d) in at least one of said column walls being capable of
buckling beneath a protuberance that is located on the cushioned
object.
10. A method for producing a cushioning element comprising the
steps of: forcing molten gel through an extrusion die having an
aperture periphery, an aperture, and a forming rod; said forming
rod being located within said aperture; cutting said gel as it
exits said extrusion die, cooling said molten in a cooling medium
to form a cushioning element, said cushioning element including
hollow columns, each column having a column wall, and bonding at
least two of said columns together to form a bonded cushioning
element, the cushioning element having a plurality of said columns,
each of said columns having a longitudinal axis along its length,
each of said columns having a column wall which defines a column
interior, and each of said columns having two ends and wherein said
columns are capable of buckling.
11. The method for producing a cushioning element as recited in
claim 10, wherein said bonding comprises: (a) melting a portion of
said column walls; (b) contacting melted portions of said column
walls; (c) allowing said melted portions of said column walls to
fuse together; (d) allowing said column walls to solidify.
12. The method for producing a cushioning element as recited in
claim 11, wherein said bonding further comprises: (a) use of
heating cores wherein said heating cores comprise heating edges
positioned within said columns and in contact with said portions of
said column walls to be melted; (b) heating said heating cores to a
temperature sufficient to melt said solidified gel to create molten
gel; (c) sustaining the heat until the contacted portions of said
portions of said column walls are molten and fuse with neighboring
molten said portions of said column walls; (d) cooling said molten
gel to re-form said solidified gel.
13. The method for producing a cushioning element as recited in
claim 10, wherein a cross section of said columns taken orthogonal
to said longitudinal axis of said column has a shape selected from
the group consisting of triangular, square, rectangular,
pentagonal, heptagonal, octagonal, round, oval, and n-sided
polygonal where n is an integer.
14. The method for producing a cushioning element as recited in
claim 12, wherein said temperature is not high enough to burn said
solidified gel or said molten gel.
15. The method for producing a cushioning element as recited in
claim 12, wherein said heating core is coated with a non-stick
surface.
16. The method for producing a cushioning element as recited in
claim 13, wherein said non-stick surface is Teflon.
17. The method for producing a cushioning element as recited in
claim 12, wherein said heating core holds outer surfaces of said
columns against one another.
18. The method for producing a cushioning element as recited in
claim 12, wherein securing cores secure said columns from sliding
side-to-side in relation to one another.
19. The method for producing a cushioning element as recited in
claim 18, wherein said securing cores have a non-stick surface.
20. The method for producing a cushioning element as recited in
claim 19, wherein said non-stick surface includes Teflon paper.
21. The method for producing a cushioning element as recited in
claim 12, wherein said columns have a square shape in cross section
through the longitudinal axis and wherein said contacted portions
are inner surface corners of said columns.
22. The method for producing a cushioning element as recited in
claim 21, wherein said heating cores hold outer surfaces of said
corners against one another.
23. The method for producing a cushioning element as recited in
claim 2221, wherein securing cores secure said columns from sliding
side-to-side in relation to one another.
24. The method for producing a cushioning element as recited in
claim 2323, wherein said securing cores have non-stick
surfaces.
25. The method for producing a cushioning element as recited in
claim 24, wherein said non-stick surface includes Teflon paper.
26. The method for producing a cushioning element as recited in
claim 10, wherein said molten gel includes elastomer gel
pre-compounded at a temperature of about 470 degrees Fahrenheit and
said forcing of said molten gel through said extrusion die is at
about 425 degrees Fahrenheit before said cooling occurs.
27. The method for producing a cushioning element as recited in
claim 26, wherein said pre-compounding and said forcing is done
with an extruder screw.
28. The method for producing a cushioning element as recited in
claim 10, wherein pressure in said extrusion die is from about 200
to about 4000 pounds per square inch.
29. The method for producing a cushioning element as recited in
claim 10, wherein extrusion is conducted into water.
30. The method for producing a cushioning element as recited in
claim 29, wherein the direction of said extrusion is upward into
said water.
31. A cushioning element made according to the method recited in
claim 10, the cushioning element comprising: (a) a quantity of said
solidified gel formed to have a top, a bottom, and an outer
periphery, said solidified gel being compressible so that it will
deform under the compressive force of a cushioned object, (b)
wherein the cushioning element is adapted to have a cushioned
object placed in contact with said top; wherein each of said column
ends is positioned at two different points of said column axis; (c)
wherein at least one of said columns is positioned within said
solidified gel such that said column axis is positioned generally
parallel to the direction of a compressive force exerted on the
cushioning element by a cushioned object in contact with said
cushioning medium; (d) and wherein at least one of said column
walls is capable of buckling beneath a protuberance that is located
on the cushioned object.
32. A method for producing a cushioning element wherein the
cushioning element includes a flexible, resilient, solidified gel
having shape memory and being substantially solid and non-flowable
at temperatures below 130 degrees Fahrenheit, comprising the steps
of: forcing molten gel through an extrusion die that has forming
rods, an aperture and an aperture periphery, the extrusion die
being shaped to extrude an elastomer gel into a cushioning element
with buckling columns, cutting said gel as it exits said extrusion
die, and cooling said cut gel in a liquid cooling medium until it
solidifies for further handling.
33. The method for producing a cushioning element as recited in
claim 32, wherein said molten gel includes elastomer gel
pre-compounded at a temperature of about 470 degrees Fahrenheit and
said forcing of said molten gel through said extrusion die is at
about 425 degrees Fahrenheit before said cooling occurs.
34. The method for producing a cushioning element as recited in
claim 33, wherein said pre-compounding and said forcing is done
with an extruder screw.
35. The method for producing a cushioning element as recited in
claim 32, wherein pressure in said extrusion die is from 200 to
4000 pounds per square inch.
36. The method for producing a cushioning element as recited in
claim 3232, wherein extrusion is into water.
37. The method for producing a cushioning element as recited in
claim 3636, wherein said extrusion takes place in an upward
direction into said water.
38. The method for producing a cushioning element as recited in
claim 32, wherein a cross section of one of said columns taken
orthogonal to said longitudinal axis of said column has a shape
selected from the group consisting of triangular, square,
rectangular, pentagonal, heptagonal, octagonal, round, oval, and
n-sided polygonal where n is an integer.
39. A method for producing a cushioning element wherein the
cushioning element includes a flexible, resilient, solidified gel
having shape memory and being substantially solid and non-flowable
at temperatures below 130 degrees Fahrenheit comprising the steps
of: (a) forcing molten gel through an extrusion die having an
aperture periphery, an aperture, and a forming rod; (i) where said
aperture periphery is a shape that will produce columns during an
elastomer extrusion process; and (ii) where said forming rod is
within said aperture; (b) cooling said molten gel as it traverses
through said extrusion die causing said molten gel to become said
solidified gel during or at some time following its departure from
said extrusion die, thereby creating a tube; (c) cutting said tube
as it leaves said extrusion die, wherein cut tubes comprise said
columns wherein said columns are hollow; and (d) bonding said
columns together to form the cushioning element.
40. The method for producing a cushioning element as recited in
claim 39, wherein said bonding step comprises: melting a portion of
said column walls; contacting melted portions of said column walls;
allowing said melted portions of said column walls to fuse
together; and allowing said column walls to solidify fused
walls.
41. The method for producing a cushioning element as recited in
claim 40, wherein said bonding step further comprises: use of
heating cores wherein said heating cores comprise heating edges
positioned within said columns and in contact with said portions of
said column walls to be melted; heating said heating cores to a
temperature sufficient to melt said solidified gel to create molten
gel; sustaining the heat until the contacted portions of said
portions of said column walls are molten and fuse with neighboring
molten said portions of said column walls; cooling the molten gel
to re-form solidified gel.
42. The method for producing a cushioning element as recited in
claim 41, wherein said heating core holds outer surfaces of said
columns against one another.
43. The method for producing a cushioning element as recited in
claim 41, wherein securing cores secure said columns from sliding
side-to-side in relation to one another.
44. The method for producing a cushioning element as recited in
claim 4343, wherein said securing cores have non-stick
surfaces.
45. The method for producing a cushioning element as recited in
claim 4444, wherein said non-stick surfaces include Teflon
paper.
46. The method for producing a cushioning element as recited in
claim 4141, wherein said columns have a square shape in cross
section through the longitudinal axis and wherein said contacted
portions are inner surface corners of said columns.
47. The method for producing a cushioning element as recited in
claim 4646, wherein said wherein said heating cores hold outer
surfaces of corners against one another.
48. The method for producing a cushioning element as recited in
claim 4646, wherein securing cores secure said columns from sliding
side-to-side in relation to one another.
49. The method for producing a cushioning element as recited in
claim 48, wherein said securing cores include non-stick
surfaces.
50. The method for producing a cushioning element as recited in
claim 49, wherein said non-stick surfaces include Teflon paper.
51. The method for producing a cushioning element as recited in
claim 41, wherein said temperature is not high enough to burn said
solidified or molten gel.
52. The method for producing a cushioning element as recited in
claim 4141, wherein said heating core is coated with a non-stick
coating.
53. The method for producing a cushioning element as recited in
claim 52, wherein said non-stick coating includes Teflon.
54. The method for producing a cushioning element as recited in
claim 3939, wherein said molten gel includes elastomer gel
pre-compounded at a temperature of nto less than about 470 degrees
Fahrenheit and said forcing of said molten gel through said
extrusion die is at not less than about about 425 degrees
Fahrenheit before said cooling occurs.
55. The method for producing a cushioning element as recited in
claim 5454, wherein said pre-compounding and said forcing is done
with an extruder screw.
56. The method for producing a cushioning element as recited in
claim 39, wherein pressure in said extrusion die is from about 200
to about 4000 pounds per square inch.
57. The method for producing a cushioning element as recited in
claim 3939, wherein extrusion takes place into water.
58. The method for producing a cushioning element as recited in
claim 5757, wherein said extrusion is upward into said water.
59. The method for producing a cushioning element as recited in
claim 5757, wherein said extrusion is downward into said water.
60. The method for producing a cushioning element as recited in
claim 39, wherein a cross section of said tubes has a shape
selected from the group consisting of triangular, square,
rectangular, pentagonal, heptagonal, octagonal, round, oval, and
n-sided polygonal where n is an integer.
Description
PRIORITY
[0001] This patent application is a divisional of U.S. patent
application Ser. No. 10/059,101 filed on Nov. 8, 2001, now ______,
which is a continuation-in-part of Untied States patent application
Ser. No. 09/303,919 filed May 3, 1999, now U.S. Pat. No. 6,413,458,
which is a continuation-in-part of U.S. patent application Ser. No.
08/968,750 filed on Aug. 13, 1997, now U.S. Pat. No. 6,026,527,
which is a continuation-in-part of U.S. patent application Ser. No.
08/601,374 filed on Feb. 14, 1996, now U.S. Pat. No. 5,749,111,
which is a continuation-in-part of U.S. patent application Ser. No.
08/783,413 filed on Jan. 10, 1997, now U.S. Pat. No. 5,994,450 and
priority to and benefit of each of the foregoing is claimed. This
patent application is also a divisional of U.S. patent application
Ser. No. 10/059,101 filed on Nov. 8, 2001, now ______, which is a
continuation-in-part of U.S. patent application Ser. No. 09/932,393
field on Aug. 17, 2001, now ______, which is a continuation-in-part
of U.S. patent application Ser. No. 09/303,979 filed on May 3,
1999, now U.S. Pat. No. 6,413,458, which claims benefit of U.S.
Provisional Patent Application Ser. No. 60/226,726 filed on Aug.
18, 2000, and priority to and benefit of each of the foregoing is
claimed.
BACKGROUND
[0002] This subject matter herein invention relates to the field of
cushioning devices, gelatinous elastomers and devices made
therefrom. More particularly, some embodiments relate to a cushion
or cushioning device made in whole or in part of gelatinous
elastomer, gelatinous visco elastomer, and the elastomers
themselves, methods for making any of the foregoing, and structures
made from the foregoing and other cushioning structures and other
devices including gelatinous elastomers.
SUMMARY
[0003] Various cushioning devices and materials are disclosed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1 depicts one embodiment of the cushion as part of an
office chair.
[0005] FIG. 2 depicts one embodiment of the cushion including its
cushioning element and cover.
[0006] FIG. 3 depicts a cutaway of one embodiment of the cushion of
FIG. 1 at 3-3.
[0007] FIG. 4 depicts a mold which may be used to manufacture one
embodiment of the cushion.
[0008] FIG. 5 depicts an alternative mold for manufacturing one
embodiment of the cushion.
[0009] FIG. 6 depicts a cross sectional view of a cushion
manufactured using the mold of FIG. 5.
[0010] FIG. 7 depicts an isometric view of an alternative
embodiment of the cushion.
[0011] FIG. 8 depicts a top view of an alternative embodiment of
the cushion.
[0012] FIG. 9 depicts an isometric view of an alternative
embodiment of the cushion.
[0013] FIG. 10 depicts a top view of an alternative embodiment of
the cushion.
[0014] FIG. 11 depicts a cross sectional view of a column of an
example cushion during buckling.
[0015] FIG. 12 depicts a cross sectional view of a column of an
example cushion during another mode of buckling.
[0016] FIG. 13 depicts forces in play as an example cushion
buckles.
[0017] FIG. 14 depicts an alternative structure for a column and
its walls.
[0018] FIG. 15 depicts a cross section of a cushion using
alternating stepped columns.
[0019] FIG. 16 depicts am alternative embodiment of the cushioning
element having gas bubbles within the cushioning media.
[0020] FIG. 17 depicts an example cushion in use with a combination
base and container.
[0021] FIG. 18 depicts an example cushion having side wall
reinforcements to support the cushioning element.
[0022] FIG. 19 depicts an example cushioning element having a
girdle or strap about its periphery to support the cushioning
element.
[0023] FIG. 20 depicts an example cushioning element with closed
column tops and bottoms and fluid or other cushioning media
contained within the column interiors.
[0024] FIG. 21 depicts an example cushioning element with firmness
protrusions placed within the column interiors.
[0025] FIG. 22 is a frontal perspective view of an embodiment of
the cushioning element which include multiple individual cushioning
units.
[0026] FIG. 23a is a frontal perspective view of an embodiment of
the cushioning element in which a first cushioning medium is
contained within a second cushioning medium.
[0027] FIG. 23b is a cross section taken along line 23b-23b of FIG.
23a.
[0028] FIG. 23c is a frontal perspective view of an alternate
configuration of the embodiment shown in FIG. 23a.
[0029] FIG. 23d is a cross section taken along line 23d-23d of FIG.
23c.
[0030] FIG. 24a is a frontal perspective view of an embodiment of
the cushioning element in which the! outer surfaces of the
cushioning medium are covered with a coating.
[0031] FIG. 24b is a cross section taken along line 24b-24b of FIG.
24a.
[0032] FIG. 25a is a perspective view of an embodiment of the
cushioning element, wherein the cushion includes multiple sets of
parallel columns and wherein each column intersects no columns of
another parallel column set or columns of only one other set.
[0033] FIG. 25b is a cross section taken along line 25b-25b of FIG.
25a.
[0034] FIG. 25c is a cross section taken along line 25c-25c of FIG.
25a.
[0035] FIG. 25d is a perspective view of an alternative
configuration of the embodiment shown in FIG. 25a, wherein each
column may intersect columns of any number of the other parallel
column sets.
[0036] FIG. 25e is a cross section taken along line 25e-25e of FIG.
25d.
[0037] FIG. 25f is a cross section taken along line 25f-25f of FIG.
25d.
[0038] FIG. 26 is a frontal perspective view of an embodiment of
the cushioning element wherein the cushion has multiple sets of
parallel narrow columns.
[0039] FIG. 27a is a frontal perspective view of an embodiment of
the cushioning element which includes multiple sets of parallel
columns and cavities formed in the column walls.
[0040] FIG. 27b is a cross section taken along line 27b-27b of FIG.
27a.
[0041] FIG. 27c is a cross section taken along line 27c-27c of FIG.
27a.
[0042] FIG. 28 is a frontal perspective view of an embodiment of
the cushioning element which has a contoured surface and includes
columns of more than one height.
[0043] FIG. 29 is a frontal perspective view of an embodiment of
the cushioning element wherein the cushioning medium is foamed.
[0044] FIG. 30a is a frontal perspective view of an embodiment of
the cushioning element wherein the column walls are formed from
numerous short tubular pieces, which create voids in the column
walls.
[0045] FIG. 30b is a frontal perspective view of an alternative
configuration of the cushioning element shown in FIG. 30a, wherein
the column walls include voids created by extracting space
consuming objects therefrom following molding of the cushioning
medium.
[0046] FIG. 31a depicts a carbon atom and its covalent bonding
sites.
[0047] FIG. 31b depicts a hydrogen atom and its covalent bonding
site.
[0048] FIG. 31c depicts a four carbon hydrocarbon molecule known as
butane.
[0049] FIG. 32a depicts a triblock copolymer useful in a cushioning
medium.
[0050] FIG. 32b depicts the triblock copolymer of FIG. 32a in a
relaxed state.
[0051] FIG. 33a depicts the chemical structure of a styrene
molecule.
[0052] FIG. 33b depicts the chemical structure of a benzene
molecule.
[0053] FIG. 33c depicts the chemical structure of an aryl
group.
[0054] FIG. 33d depicts, the chemical structure of an-enyl
group.
[0055] FIG. 33e depicts the chemical structure of an ethenyl
group.
[0056] FIG. 33f depicts the chemical structure of a propenyl
group.
[0057] FIG. 34a depicts a midblock (B) of the triblock copolymer of
FIG. 32a. 8
[0058] FIG. 34b depicts an endblock (A) of the triblock copolymer
of FIG. 32a.
[0059] FIG. 34c depicts the weak bonding between the monomer unites
of one or more midblocks (B) of the triblock copolymer of FIG.
32a.
[0060] FIG. 34d depicts an endblock (A) of the triblock copolymer
of FIG. 32a, showing the endblock (A) in a relaxed state.
[0061] FIG. 35a depicts the chemical structure of hydrocarbon
molecules known as alkanes.
[0062] FIG. 35b depicts the chemical structure of hydrocarbon
molecules known as alkenes.
[0063] FIG. 35c depicts the chemical structure of hydrocarbon
molecules known as alkynes.
[0064] FIG. 35d depicts the chemical structure of a hydrocarbon
molecule known as a conjugated diene.
[0065] FIG. 35e depicts the chemical structure of a hydrocarbon
molecule known as an isolated diene.
[0066] FIG. 36a depicts the chemical structure of a
poly(ethylene/butylene) molecule.
[0067] FIG. 36b depicts the chemical structure of a
poly(ethylene/propylene) molecule.
[0068] FIG. 36c depicts the chemical structure of a 1,3-butadiene
molecule.
[0069] FIG. 36d depicts the chemical structure of an isoprene
molecule.
[0070] FIG. 37a depicts
polystyrene-poly(ethylene/butylene)-polystyrene.
[0071] FIG. 37b depicts
polystyrene-poly(ethylene/propylene)-polystyrene.
[0072] FIG. 37c depicts polystyrene-polybutadiene-polystyrene.
[0073] FIG. 37d depicts polystyrene-polyisoprene-polystyrene.
[0074] FIG. 37e depicts
polystyrene-poly(isoprene+butadiene)-polystyrene.
[0075] FIG. 37f depicts polystyrene-poly
(ethylene/butylene+ethylene/propy- lene)-polystyrene.
[0076] FIG. 38a depicts the chemical structure of
polystyrene-poly(ethylen-
e/butylene+ethylene/propylene)-polystyrene.
[0077] FIG. 38b depicts the group of the triblock copolymers of
FIG. 321a, showing weak attraction of the endblocks to each
other.
[0078] FIG. 39a illustrates plasticizer association with the group
of triblock copolymers of FIG. 38b.
[0079] FIG. 39b illustrates the lubricity theory of plasticization,
showing two midblocks (B) moving away from each other.
[0080] FIG. 39c illustrates the lubricity theory of plasticization,
showing two midblocks (B) moving toward each other.
[0081] FIG. 39d illustrates the lubricity theory of plasticization,
showing two midblocks (B) moving across each other.
[0082] FIG. 39e illustrates the gel theory of plasticization,
showing a weak attraction between two midblocks (B) when
plasticizer is not present.
[0083] FIG. 39f illustrates the gel theory of plasticization,
showing a plasticizer molecule breaking the weak attraction of FIG.
39e.
[0084] FIG. 39g illustrates the mechanistic theory of
plasticization, showing an equilibrium of plasticizer breaking the
weak attraction of midblocks (B) for each other.
[0085] FIG. 39h illustrates the free volume theory of
plasticization, showing the free space associated with a midblock
(B).
[0086] FIG. 39i illustrates the theory of FIG. 39h, showing that as
small plasticizer molecules are added, the free space in a given
area increases.
[0087] FIG. 39j illustrates the theory of FIG. 39h, showing the
even small plasticizers provide an even greater amount of free
space.
[0088] FIG. 40a depicts the use of an extruder to perform a method
for foaming gel cushioning media.
[0089] FIG. 40b depicts the use of an injection molding machine to
perform a method for foaming a gel cushioning media.
[0090] FIG. 41 depicts an embodiment of a cushioning element,
wherein a plurality of tubes are bonded together to form the
cushion.
[0091] FIG. 42 depicts a method for bonding the individual tubes of
FIG. 41 together to form the cushioning element shown therein.
[0092] FIG. 43 depicts cut foam bun of step 1.
[0093] FIG. 44 depicts cut foam bun of step 2.
[0094] FIG. 45 depicts cut foam bun of step 3.
[0095] FIG. 46 depicts bonded foam of step 4.
[0096] FIG. 47 depicts insertion of side support pieces of step
5.
[0097] FIG. 48 depicts top view of bottom core piece.
[0098] FIG. 51 depicts cut foam bun of step 1.
[0099] FIG. 52a depicts separated foam of step 2.
[0100] FIG. 52b depicts aligned foam of step 3.
[0101] FIG. 53 depicts bonded foam of step 4.
[0102] FIG. 54 depicts compressed foam rail.
[0103] FIG. 55 depicts foam and gellycomb cross-section.
[0104] FIG. 56 depicts foam and gellycomb with pillow-top layer in
cross-section.
[0105] FIG. 57 depicts foam and gellycomb with two pillow-top
layers in cross-section.
[0106] FIG. 58 depicts foam and gellycomb cross-section.
[0107] FIG. 59 depicts foam and gellycomb with gellycomb comfort
layer cross-section.
[0108] FIG. 60a depicts side view with foam inserted.
[0109] FIG. 60b depicts side view of foam construction.
[0110] FIG. 60c depicts front view of foam construction.
[0111] FIG. 61 depicts foam insertion of step 1.
[0112] FIG. 62 depicts a cut-away view of foam.
[0113] FIG. 63 depicts gellycomb pillow-top layer.
[0114] FIG. 64 depicts gellycomb pillow-top layer with two
layers.
[0115] FIG. 65 depicts foam construction.
[0116] FIG. 66 depicts foam construction.
[0117] FIG. 67a depicts the no tool assembly.
[0118] FIG. 67b depicts the no tool assembly of step 1.
[0119] FIG. 67c depicts folded down sides of step 2.
[0120] FIG. 67d depicts snapped corners of step 3.
[0121] FIG. 67e depicts loam construction.
[0122] FIG. 68a depicts flat construction.
[0123] FIG. 68b depicts folded down construction.
[0124] FIG. 69a depicts top view.
[0125] FIG. 69b depicts front view.
[0126] FIG. 69c depicts end view.
[0127] FIG. 70 depicts quilted top with fiber and gel elastomer
layer.
[0128] FIG. 71 depicts quilted top with fiber and two gel elastomer
layers.
[0129] FIG. 72 depicts quilted top with fiber and foam and thicker
gel elastomer layer.
[0130] FIG. 73 depicts quilted top with fiber and one thin gel
elastomer layer and one thick gel elastomer layer.
[0131] FIG. 74 depicts quilted top with fiber, two thin gel
elastomer layers and one thick gel elastomer layer.
[0132] FIG. 75 depicts quilted top with fiber, one thin gel
elastomer layer, and polyurethane foam.
[0133] FIG. 76 depicts quilted top with fiber, two thin gel
elastomer layers, and polyurethane
[0134] FIG. 77 depicts quilted top with fiber, one thin gel
elastomer layer, and high-grade visco-foam.
[0135] FIG. 78 depicts quilted top with fiber, one thin gel
elastomer layer, and spring unit.
[0136] FIG. 79 depicts quilted top with fiber, two thin gel
elastomer layers, and spring unit.
[0137] FIG. 80 depicts quilted top with fiber and foam, thick gel
elastomer layer, and spring unit
[0138] FIG. 81 depicts quilted top with fiber, thin gel elastomer
layer, and latex foam.
[0139] FIG. 82 depicts quilted top with fiber, latex topper, and
thick gel elastomer layer.
[0140] FIG. 83 depicts quilted top with fiber, latex foam, and
thick gel elastomer layer.
[0141] FIG. 84 depicts quilted top with fiber, polyurethane foam,
and thick gel elastomer layer.
[0142] FIG. 85 depicts quilted top with fiber, pillow-soft
polyurethane foam, and thick gel elastomer.
[0143] FIG. 86 depicts inserted molten material.
[0144] FIG. 87 depicts pearlized chintz quilt with foam and fiber;
Intellifoam; and non-skid fabric.
[0145] FIG. 88 depicts pearlized chintz pillow-top with foam
convoluted foam and fiber; Intelli-foam; and non-skid :fabric.
[0146] FIG. 89 depicts Belgian damask quilt with foam and fiber;
SuperSoft latex; Intellifoam; and Belgian damask tick.
[0147] FIG. 90 depicts Belgian damask quilt with foam and fiber;
SuperSoft Latex; Intellifoam; Firmsoft; and Belgian damask
tick.
[0148] FIG. 91 depicts Belgian damask quilt with Supersoft fiber;
SuperSoft latex; IntelLatex; Intelli-loam; and Belgian damask
tick.
[0149] FIG. 92 depicts Belgian damask quilt with foam and fiber;
Intelli-Gel; and Belgian damask: tick.
[0150] FIG. 93 depicts Belgian damask quilt with foam and fiber;
Intelli-foam; Intelli-Gel; and Belgian Damask Tick.
[0151] FIG. 94 depicts pearlized chintz quilt with foam and fiber;
Intelli-foam;
[0152] springs; and non-skid fabric.
[0153] FIG. 95 depicts Belgian damask quilt with Supersoft fiber;
IntelLatex;
[0154] springs; and Belgian Damask tick.
[0155] FIG. 96 depicts stretch knit cover; Memory-foam; and
Intelli-foam.
[0156] FIG. 97 depicts stretch knit cover; SuperSoft latex; and
IntelLatex.
DETAILED DESCRIPTION
[0157] Configuration of the Cushions
[0158] FIG. 1 depicts a cushioned object 101, in this instance a
human being, atop of a piece of furniture 102, in this instance a
chair, which includes the cushion 103. Although in this embodiment,
the cushion 103 is depicted as part of an office chair, the cushion
may be used with many types of products, including furniture such
as sofas, love seats, kitchen chairs, mattresses, lawn furniture,
automobile seats, theatre seats, padding found beneath carpet,
padded walls for isolation rooms, padding for exercise equipment,
wheelchair cushions, bed mattresses, and others.
[0159] Referring to FIG. 2, the cushion 103 of FIG. 1 is depicted
in greater detail. The cushion 103 includes a cover 204. An example
cover is a durable and attractive fabric, such as nylon, cotton,
fleece, synthetic polyester or another suitable material which may
be stretchable and elastic and which readily permits the flow of
air through it to enhance ventilation of a cushioned object. Within
the cover 204, a cushioning element 205 is to be found. As can be
seen from FIG. 2, the cushioning element 205 comprises a cushioning
media of a desired shape. In the embodiment depicted, the
cushioning element 205 includes gel cushioning media formed
generally into a rectangle with four sides, a top and a bottom,
with the top and bottom being oriented toward the top and bottom of
the page, respectively. The cushioning element has within its
structure a plurality of hollow columns 206. As depicted, the
hollow columns 206 contain only air. The hollow columns 206 are
open to the atmosphere and therefore readily permit air circulation
through them, through the cover 204 fabric, and to the cushioned
object. The columns 206 have column walls 207 which in the
embodiment depicted are hexagonal in configuration. The total
volume of the cushioning element may be occupied by not more than
about 50% gel cushioning media, and that the rest of the volume of
the cushioning element will be gas or air. The total volume of the
cushioning element may be occupied by as little as about 9%
cushioning media, and the rest of the volume of the cushion will be
;gas or air. This yields a lightweight cushion with a low overall
rate of thermal transfer and a law overall thermal mass. It is not
necessary that this percentage be complied with in every
instance.
[0160] Referring to FIG. 3, a cushioned object 101, in this
instance a human being, is depicted being cushioned by the cushion
103 which includes cushioning element 205 within cover 204. Also
visible is a cushion base 301 of a rigid material such as wood,
metal, plastic on which the cushioning element 205 rests. The
cushioning element 206 includes hollow columns 206 with walls 207.
It can be seen that beneath the most protruding portion of the
cushioned object, in this instance a hip bone 302, the hollow
columns 303 have walls 304 which have partially or completely
buckled in order to accommodate the protuberance 302 and avoid
creating a high pressure point below the protuberance 302 in
response to the compressive force exerted by the cushioned object.
Buckled columns offer little resistance to deformation, thus
removing pressure from the hip bone; area. It can also be seen that
in portions of the cushioning element 205 which are not under the
protuberance 302, the cushioning media which forms the walls 304 of
the hollow columns 303 has compressed but the columns 303 have not
buckled, thus loading the cushioned object across the broad surface
area of its non-protruding portions. The cushion is yieldable as a
result of the compressibility of the cushioning media and the
bucklability of the columns (or column walls). The cushion 103 is
depicted as having been manufactured using the mold depicted in
FIG. 4. It can be seen from this cushion's response to a
compressive force exerted by the cushioned object that the cushion
and the cushioning element are adapted to have a cushioned object
placed on top of them.
[0161] Referring to FIG. 6, a cross section of an alternative
embodiment is depicted. The cushioning element 601 includes
cushioning media 604 (which may be a gel cushioning media) which
form walls 605 for columns 602, 603. It can be seen that the
columns 602 and 603 are oriented into a group protruding from the
top of the cushioning element 601 down into the cushioning media
604 but not reaching the bottom of the cushioning element of which
column 602 is a member, and a group protruding from the bottom of
the cushioning element 601 into the cushioning element 601 but not
reaching the top of the cushioning element 601 of which column 602
is a member. This yields a generally firmer cushion than that shown
in some other figures. This cushion would be manufactured by the
mold depicted in FIG. 5.
[0162] Referring to FIG. 7, an alternative embodiment of a
cushioning element 701 is depicted. The cushioning element includes
cushioning media 702, columns 703 and column walls 704. The columns
depicted in FIG. 7 are square in a cross section taken orthogonal
to their longitudinal axis, in contrast to the columns of FIG. 2
which are hexagonal in a cross section taken orthogonal to their
longitudinal axis. It is also of note that in FIG. 7, the columns
703 are arranged as an n.times.m matrix with each row and each
column of columns in the matrix being aligned perfectly adjacent to
its neighbor, with no offsetting. Exemplary sizing and spacing of
columns would include columns which have a cross sectional diameter
taken Referring to FIG. 8, a top view of an alternative cushioning
element 801 is depicted. The cushioning element 801 includes
cushioning media 802 which forms column walls 804, columns 803 and
an exterior cushioning element periphery 805. It can be seen that
the columns 803 of FIG. 8 are arranged in offset fashion with
respect to some of the columns to which they are adjacent. A myriad
of column arrangements are possible, from well-organized
arrangements of the columns to a random columnar arrangement. The
columns may be arranged so that the total volume of gel cushioning
media 802 within the volume of space occupied by the cushioning
element 801 is minimized. This results in a lightweight cushion. To
that end, the columns 803 may be arranged in close proximity to
each other in order to minimize the thickness of the column walls
804. This will result in a lighter cushion and a cushion that will
yield to a greater extent under a cushioned object of a given
weight than a similar cushion with thicker column walls 804.
[0163] Referring to FIG. 9, an alternative cushioning element 901
is depicted with cushioning media 902, columns 903, column walls
904 and outer periphery 905 of the cushioning element 901 being
shown. The columns 902 depicted are round in a cross section taken
orthogonal to their longitudinal axes. The reader should note that
it may be desirable to include a container or side walls which will
contain the outer periphery 905 of the cushioning element. For
example, in FIG. 9, a rectangular box with interior dimensions just
slightly larger than the exterior dimensions of the cushioning
element 901 could be employed. Or, as shown in FIG. 1, the side
walls of the cover 204 could be rigid, such as by the use of
plastic inserts. The effect of rigid side walls or a rigid
container for a cushioning element is that when a cushioned object
is placed on the cushioning element, the cushioning media will not
be permitted to bulge outward at the cushioning element outer
periphery. By preventing such outward bulging, greater cushion
stability is achieved and a more direct (i.e. in a direction
parallel to the longitudinal axis of a column, which in most of the
figures, such as FIG. 3, is assumed to be in the direction of the
Earth's gravity but which may not always be so) movement or descent
of the cushioned object into the cushion is achieved. A direct
movement or descent of a cushioned object into the cushion (i.e.
parallel to the longitudinal axes of the columns) is desired
because the column walls are configured to absorb weight and
cushion the cushioned object, or, if the load under a protuberance
gets high enough, by buckling of the columns. If a cushioned object
travels a substantial distance sideways in the cushion, the hollow
portion of the columns may be eliminated by opposing column walls
collapsing to meet each other rather than either substantially
compressing the cushioning media or by buckling as depicted in
FIGS. 13 and 14. This would not provide the desired cushioning
effect as it would result in collapsed columns within the cushion
(rather than buckled columns), and the cushion would have little
more cushioning effect than a solid block of the cushioning media
without the columns.
[0164] Referring to FIG. 10, an alternative embodiment of the
cushion 1001 is depicted. The cushion 1001 includes gel cushioning
media 1002 in the form of an outer cushion periphery 1003, and
column walls 1004 which form triangular hollow columns 1005. The
reader should note that the columns of the various figures are
merely illustrative, and in practice, the columns could be
triangular, rectangular, square, pentagonal, hexagonal, heptagonal,
octagonal, round, oval, n-sided or any other shape in a cross
section taken orthogonal to the longitudinal axis of a column. The
periphery of the cushioning element may also be triangular,
rectangular, square, pentagonal, hexagonal, heptagonal, octagonal,
round, oval, heart-shaped, kidney-shaped, elliptical, oval,
egg-shaped, n-sided or any other shape.
[0165] FIG. 11 depicts a column 1101 including column walls 1102
and 1103 and column interior 1104. The column 1101 has a
longitudinal axis 1105 which can be oriented in the cushion
parallel to the direction of the longitudinal axis of a column
which should be the direction that the cushioned object sinks into
the cushion. Thus, the column top 1106 is at the side of the
cushion that contacts the cushioned object, and the column bottom
1107 is at the side of the cushion that typically faces the ground
and will rest on some sort of a base. Another way of describing
this with respect to the longitudinal axis of each column is that
the column top is at one end of the longitudinal axis of a column
and the column bottom is at the other end of the longitudinal axis
of a column. When an object to be cushioned is placed onto a
cushion which contains many such columns 1101, such as is shown in
FIG. 3, a depressive force 1108 is applied to the cushion and to
the column 1101 by the cushioned object. Because the cushion is
expected to rest on some type of supporting surface, such as a
base, a reaction force 1109 is provided by -the supporting surface.
The cushion, including the column 1101, yields under the weight of
the cushioned object. This yielding is a result of compression of
the cushioning media and, if the load under a protruding portion of
the cushioned object is high enough, by buckling or partial
buckling of the columns 1101. From FIG. 11, it can be seen that the
depicted column 1101 buckles because the flexible cushion walls
1102 and 1103 buckle outward around the periphery of the column, as
depicted by cross-sectional points 1110 and 1111. In other words,
the column walls buckle radically outward orthogonally from the
longitudinal axis of the column. This permits the column 1101 to
decrease in total length along its longitudinal axis 1108 and
thereby conform to the shape of protuberances on a cushioned
object. Since buckled columns carry comparatively little load, this
results in a cushion that avoids pressure peaks on the cushioned
object.
[0166] FIG. 12 depicts a column 1201 including column walls 1202
and 1203 and column interior 1204. The column 1201 has a
longitudinal axis 1205 which may be oriented in the , cushion
parallel to the direction of movement of a cushioned object
sinking, into the cushion. Thus, the column top end 1206 is at the
side of the cushion that contacts the cushioned object, and the
column bottom end 1207 is at the side of the cushion that typically
will rest on some sort of a base. When an object to be cushioned is
placed against a cushion which contains numerous columns 1201, such
as is shown in FIG. 3, a depressive force 1208 is applied to the
cushion and to the column 1201 by the cushioned object. Because the
cushion is expected to rest on some type of supporting surface,
such as a base, a reaction force 1209 is provided by the supporting
surface. The cushion, including the column 1201, yields under the
weight of the cushioned object. This yielding is a result of
compression of the cushioning media and, if the load under a
protruding portion of the cushioned object is high enough, by
buckling or partial buckling of the columns. From FIG. 12, it can
be seen that the depicted column 1201 buckles because the flexible
cushion wall 1202 buckles outward from the column center or
orthogonal away from the longitudinal axis of the column at point
1210, while cushion wall 1203 buckles inward toward the column
center or orthogonal toward the longitudinal axis of the column at
points 1211. This buckling action causes the column 1201 to
decrease in total length along its longitudinal axis 1208 and
thereby conform to the shape of protuberances on a cushioned
object. Point 1210 is depicted buckling outward (away from the
center of the column) and point 1211 is depicted as buckling inward
(toward the center of the column). Alternatively, both points 1210
and 1211 could buckle inward toward the center of the column or
both could buckle outward. Since buckled columns carry
comparatively little load, this results in a cushion that avoids
pressure peaks on the cushioned object. Buckling of a column
permits the column to decrease in total length along its
longitudinal axis and thereby conform to the shape of protuberances
on a cushioned object. This results in a cushion that avoids
pressure peaks on the cushioned object. It should be noted by the
reader that the columns 1101 and 1201 depicted in FIGS. 11 and 12
are hollow columns which have interiors completely open to the
atmosphere and which permit air to travel through the columns to
enhance ventilation under the cushioned object. It is also of note
that the column 1201 of FIG. 12 has column walls 1202 and 1203 that
include fenestrations 1210 (which may be holes or apertures in the
column walls) that permit the flow of air between adjacent columns,
providing an enhanced ventilation effect. Fenestrations are also
useful for reducing the weight of the cushioning element. The
greater the size and/or number of fenestrations in column walls,
the less the cushion weighs. The fenestrations or holes 1210 in the
column walls could be formed by punching or drilling, or they could
be formed during molding of the cushioning element.
[0167] FIG. 13 depicts an alternative column 1301 including column
walls 1302 and 1303 and a column interior 1304. The column 1301 has
a longitudinal axis 1305 which, in the cushion, may be oriented
parallel to the direction in which the cushioned object is expected
to sink into the cushion. Thus, the column top end 1306 is at the
side of the cushion that contacts the cushioned object, and the
column bottom end 1307 is at the side of the cushion that typically
faces some sort of a base. When an object to be cushioned is placed
onto a cushion which contains column 1301, such as is shown in FIG.
3, a depressive force 1308 is applied to the cushion and to the
column 1301 by the cushioned object. Because the cushion is
expected to rest on some type of supporting surface, such as a
base, a reaction force 1309 is provided by the supporting surface.
The cushion, including the column 1301, yields under the weight of
the cushioned object. This yielding is a result of compression of
the cushioning media and, if the load under a protruding portion of
the cushioned object is high enough, by buckling or partial
buckling of the columns. From FIG. 13, it can be seen that the
depicted column 1301 buckles because the flexible cushion walls
1302 and 1303 buckle outward from the column center or orthogonal
away from the longitudinal axis 1305 of the column at points 1311
and 1310. This buckling action allows the column 1301 to decrease
in total length along its longitudinal axis 1305 and thereby
conform to the shape of protuberances on a cushioned object.
[0168] In the embodiment depicted, the column 1301 is a sealed
column containing air or an inert gas within its interior 1304.
Thus, as the column 1301 decreases in length along its longitudinal
axis, the gas within the column interior 1304 tends to support the
column top end 1306 and resist the downward movement of the
cushioned object. This yields a firmer cushion. Alternatively, open
or closed cell (or other) foam or fluid cushioning media could be
provided within the interior of the columns or within some of them
in order to increase the firmness of the cushion.
[0169] FIG. 14 depicts an alternative embodiment of the column. The
column 1401 depicted has column walls 1402 and 1403 and a column
interior 1404. The column interior 1404 is open at column top end
1405 and at column bottom end 1406 to permit air to pass through
the column 1401. Column 1401 has walls 1402 and 1403 which are
thicker at their bottom end 1406 than at their top end 1405,
imparting cushions which include such columns with a soft
cushioning effect when cushioning an object that sinks into the
cushion to only a shallow depth, but progressively providing firmer
cushioning the deeper the cushioned object sinks. This
configuration of column 1401 permits the construction of a cushion
which accommodates cushioned objects of a very wide variety of
weight ranges. Alternatively, the column walls could be thicker at
the top than at the bottom, the column walls could be stepped, or
the column walls could have annular or helical grooves in them to
facilitate buckling under the load of a cushioned object.
Additionally, the column interior could be of a greater interior
dimension orthogonal to its longitudinal axis at one end than at
the other. Or the columns could be of varying dimension and shape
along their longitudinal axes.
[0170] FIG. 15 depicts a cross section of a cushioning element
using alternating stepped columns. The cushioning element 1501 has
a plurality of columns 1502 each having a longitudinal axis 1503, a
column top 1504 and a column bottom 1505. The column top 1504 and
column bottom 1505 are open in the embodiment depicted, and the
column interior or column passage 1506 is unrestricted to permit
air flow through the column 1502. The column 1502 depicted has side
walls 1507 and 1508, each of which has three distinct steps 1509,
1510 and 1511. The columns are arranged so that the internal taper
of a column due to the step on its walls is opposite to the taper
of the next adjacent column. This type of cushioning element could
be made using a mold similar to that depicted in FIG. 4.
[0171] FIG. 16 depicts an alternative embodiment of a cushioning
element 1601. The cushioning element 1601 has a plurality of
columns 1602, 1603 and 1604, each having a column interior 1605,
1606 and 1607, and column walls 1608, 1609, 1610 and 1611. The
column walls are made from cushioning; media, such as the example
soft gels herein. In the embodiment of the cushioning element 1601
depicted, the cushioning media 1612 has trapped within it a
plurality of gas bubbles 1613, 1614 and 1615. When a soft gel
cushioning medium is used, since the gel is not flowable at the
temperatures to which the cushion is expected to be exposed during
use, the bubbles remain trapped within the cushioning medium. The
use of bubbles within the cushioning medium reduces the weight of
the cushion and softens the cushion to a degree which might not
otherwise be available. Bubbles may be introduced into the
cushioning medium by injecting air, another appropriate gas, or
vapor into the cushioning medium before manufacturing the
cushioning element, by vigorously stirring the heated, flowable
cushioning medium before it is formed into the shape of a cushion,
or by utilizing a cushioning medium of a composition that creates
gas or boils at the temperatures to which it is subjected during
the manufacture of a cushioning element. Blowing agents, some of
the uses of which are described in detail below in connection with
the disclosure of the gel material, are also useful for introducing
gas bubbles into the cushioning medium. Microspheres, which we also
discussed in greater detail below, are also useful for introducing
gas pockets into the cushion medium.
[0172] FIG. 17 depicts an embodiment of the cushioning element
which has cushioning medium, solid exterior walls 1703 and 1704, a
plurality of columns 1705 and column walls 1706 forming the
columns. Note that although FIG. 17 shows a cushioning element 1701
with solid walls 1703 and 1704, it is possible to make a cushioning
element 1701 that has columns on its outer walls. The cushioning
element is disposed within an optional cover 1707. A container 1708
with relatively stiff or rigid walls 1709 and 1710 of approximately
the same size and shape as the cushioning element walls 1703 and
1704 is shown. The container 1708 has a bottom or base 1711 on
which the cushioning element is expected to rest. The container
1708 walls 1709 and 1710 serve; to restrict the outward movement of
the cushioning element 1701 when a cushioned object is placed on
it. When soft gel is used as a cushioning medium, the cushioning
element 1701 would tend to be displaced by the object being
cushioned were the side walls 1709 and 1710 of the container 1711
not provided. In lieu of a container, any type of appropriate
restraining means may be used to prevent side displacement of the
cushioning element in response to the deforming force of a
cushioned object. For example, individual plastic plates could be
placed against the side walls 1703 and 1704 of the cushioning
element 1701. Chose plates could be held in place with any
appropriate holder, such as the cover 1707. As another example, an
appropriate strap or girdle could be wrapped around all exterior
side walls 1703 and 1704 of the cushioning element 1701. Such a
strap or girdle would serve to restrain the cushioning element 1701
against radial outward displacement in response to a cushioned
object resting on the cushioning element.
[0173] FIG. 18 depicts an alternative embodiment of a cushion 1801
that includes a cushioning element 1802 and a cover 1803. The
cushioning element 1802 has side walls 1808 and 1809 about its
periphery, the side walls 1808 and 1809 in this embodiment being
generally parallel with the longitudinal axis 1810 of a hollow
column 1811 of the cushioning element 1802. A gap 1806 exists
between the cover 1803 and the side wall 1809 of the cushioning
element. This gap 1806 accommodates the insertion of a stiff or
rigid reinforcing side wall support 1804 which may be made of a
suitable material such as plastic, wood, metal or composite
material such as resin and a reinforcing fiber. Similarly, gap 1807
between side wall 1808 and the cover 1803 may have side wall
support 1805 inserted into it. The side wall supports are
configured to restrict the cushioning element from being
substantially displaced in an outward or radial direction (a
direction orthogonal to the longitudinal axis of one of the columns
of the cushioning element) so that the cushioning element's columns
will buckle to accommodate the shape of a cushioned object, rather
than permitting the cushioning element to squirm out from under the
cushioned object.
[0174] FIG. 19 depicts an alternative embodiment of a cushioning
element 1901 including square columns 1908. The cushioning element
has outer side walls 1902 and 1903 about its periphery. The reader
should note that although the outer periphery of the cushioning
element in FIG. 19 is depicted as rectangular, the outer periphery
could be of any desired configuration, such as triangular, square,
pentagonal, hexagonal, heptagonal, octagonal, any n-sided polygon
shape, round, oval, elliptical, heart-shaped, kidney-shaped,
quarter moon shaped, n-sided polygonal where n is an integer, or of
any other desired shape. The side walls 1902 and 1903 of the
cushioning element 1901 have a peripheral strap or girdle 1904
about them. The girdle 1904 has reinforcing side walls 1905 and
1906 which reinforce the structural stability of side walls 1902
and 1903 respectively of the cushioning element 1901. The
embodiment of the girdle 1904 depicted in FIG. 19 has a fastening
mechanism 1907 so that it may be fastened about the periphery of
the cushioning element 1901 much as a person puts on a belt. The
girdle 1904 serves to confine the cushioning element 1901 so that
when a cushioned object is placed on the cushioning element 1901,
the cushioning element will not tend to squirm out from beneath the
girdle 1904. Thus, the cushioning element 1901 will tend to yield
and conform to the cushioned object as needed by having; its
cushioning medium compress and its columns buckle. FIG. 20 depicts
an alternative embodiment of a cushioning element 2001. The
cushioning element 2001 includes cushioning medium 2002 such as gel
formed into column walls 2003 and 2004 to form a column 2005. The
column 2005 depicted has a sealed column top 2006 and a sealed
column bottom 2007 in order to contain a column filler 2008. The
column filler 2008 could be open or closed cell foam, any known
fluid cushioning medium such as lubricated spherical objects, or
any other desired column filler. The cushioning element 2001
depicted has an advantage of greater firmness compared to similar
cushioning elements which either omit the sealed column top and
column bottom or which omit the column filler.
[0175] FIG. 21 depicts an alternative embodiment of a cushioning
element 2101. The cushioning; element 2101 has cushioning medium
2102 formed into column walls 2103 and 2104. The column walls 2103
and 2104 form a column interior 2105. The column 25 2106 has an
open column top 2107 and a closed column bottom 2108. In the
embodiment depicted, the column 2107 has a firmness protrusion 2109
protruding into the column interior 2105 from the column bottom
2108. The firmness protrusion 2109 depicted is wedge or cone
shaped, but a firmness protrusion could be of an desired shape,
such as cylindrical, square, or otherwise in cross section along
its longitudinal axis. The purpose of the firmness protrusion 2109
is to provide additional support within a buckled column for the
portion of a cushioned object that is causing the buckling. When a
column of this embodiment buckles, the cushioning element will
readily yield until the cushioned object begins to compress the
firmness protrusion. At that point, further movement of the
cushioned object into the cushion is slowed, as the cushioning
medium of the firmness support needs to be compressed or the
firmness support itself needs to be caused to buckle in order to
achieve further movement of the cushioned object into the
cushioning medium.
[0176] Referring now to FIG. 22, in another embodiment of the
cushion, multiple individual cushioning elements 2201a, 2201b,
2201c, etc. are provided within a single cushion 2200. In such
embodiments, the cushions are positioned side-to-side, with or
without other materials between the individual cushions, and with
or without connecting the individual cushions to one another. For
example, sixty-four cushions, each having a thickness of four
inches, and four sides each two inches in length, can be placed in
an eight-by-eight arrangement to form a four inch thick square
cushion having sixteen inch sides. Such cushions may be useful
where different cushioning characteristics are desired on different
portions of a cushion. Different cushioning characteristics are
achieved through varying the materials and/or configurations of the
individual cushions.
[0177] With reference to FIGS. 23a, 23b, 23c and 23d, another
embodiment of a cushion 2301 is shown. Embodiment 2301 includes a
first cushioning medium 2302 which forms a cover and a second
cushioning medium 2303 which fills the cover. First cushioning
medium 2302 may be elastomeric gel material, which is disclosed in
detail below. Second cushioning medium 2303 may be the
visco-elastomeric material that is disclosed in detail below.
[0178] Embodiment 2301 also includes columns 2304, column walls
2305 and an outer periphery 2306. Columns 2304 are formed through
cover 2302 and lined with cushioning medium 2302. With reference to
FIGS. 23a and 23b, where two adjacent columns 2304a and 2304b are
separated only by a thin column wall 2305a (e.g., a column wall
having a thickness of only about 0.1 inch or less), the column wall
may be made from cushioning medium 2302. Where two adjacent columns
2304c and 2304d are separated by a thicker column wall 2305c, the
column wall may include a cover 2302 of the first cushioning medium
and is filled with second cushioning medium 2303.
[0179] The use of multiple cushioning media in cushion 2301
facilitates tailoring of the rebound, pressure absorption, and flow
characteristics of the cushion. Compressibility of cushion 2301
also depends upon the amount of spacing between columns and the
formulations of the first second cushioning media 2302 and 2303,
respectively.
[0180] FIGS. 24a and 24b illustrate another embodiment of the
cushioning element 2401. Referring to FIG. 24b, embodiment 2401
includes a cushioning medium 2402, a coating 2403 adhered to the
cushioning medium, columns 2404, column walls 2405 that separate
the columns, and an outer periphery 2406. Cushioning medium 2402 of
embodiment 2401 may be tacky, which facilitates adhesion of coating
2403 thereto. An example cushioning medium 2402 for use in
embodiment 2401 is disclosed in detail below. Coating 2403 may be a
particulate material, including without limitation lint, short
fabric threads, talc, ground cork, microspheres, and others.
However, coating 2403 may me made from any material that will form
a thin, pliable layer over cushioning medium 2402, including but
not limited to fabrics, stretchable fabrics, long fibers, papers,
films, and others.
[0181] FIGS. 25a, 25b, 25c, 25d, 25e and 25f show another
embodiment of a cushioning element 2501. Embodiment 2501 includes
cushioning medium 2502, a first set of columns 2503 which are
oriented along a first axis x, a second set of columns 2504 which
are oriented along a second axis y, a third set of columns 2505
which are oriented along a third axis z, column walls 2506 located
between the columns, and an outer periphery 2507. As an example,
axis x is perpendicular to both axis y and axis z and axis y is
perpendicular to axis z. Columns 2503 and 2504, 2503 and 2505,
and/or 2504 and 2505 may intersect each other. FIGS. 25a, 25b and
25c illustrate a cushion 2501 a wherein columns 2503a intersect
columns 2504 and columns 2503b intersect columns 2505. FIGS. 25d,
25e and 25f depict a cushion 2501b wherein each of columns 2503
intersect both columns 2504 and columns 2505. Alternatively, none
of the columns may intersect any other columns. Other variations of
intersection and/or non-intersecting columns are also within the
scope.
[0182] The spacing and pattern with which each set of columns is
positioned determines the total volume of cushioning medium 2502
within the volume of space occupied by the cushioning element 2501.
As the volume of cushioning medium 2502 within the volume of space
occupied by the cushioning element 2501 decreases, the cushion
becomes lighter and easier to compress. Thus, the spacing and
pattern of each set of columns may be varied to provide a cushion
of desired weight and compressibility. Cushioning elements which
have only two sets of columns or more than three sets of columns
are also within the scope of embodiment 2501.
[0183] With reference to FIG. 26, another embodiment of cushioning
element 2601 is shown which includes a first set of columns 2603
which are oriented along a first axis x, a second set of columns
2604 which are oriented along a second axis y, and a third set of
columns 2605 which are oriented along a third axis z. As can be
seen in FIG. 26, columns 2603, 2604 and 2605 may be thin. Column
walls 2606, which are made from a cushioning medium 2602, surround
each of the columns. The cushion 2601 shape is defined in part by
an outer periphery 2607. As an example, axis x is perpendicular to
both axis y and axis z and axis y is perpendicular to axis z.
Similar to the cushion of embodiment 2501, columns 2603, 2604 and
2605 may or may not intersect any other columns. Likewise, the
spacing between adjacent columns and the arrangement of each of the
columns determine the total volume of cushioning medium 2602 within
the volume of space occupied by the cushioning element 2601. As the
volume of cushioning medium 2602 within the volume of space
occupied by the cushioning element 2601 decreases, the cushion
becomes lighter and easier to compress. Thus, the spacing and
arrangement of columns may be varied to provide a cushion of
desired weight and compressibility. Cushions with only two sets of
columns or more than three sets of columns are also within the
scope of embodiment 2601.
[0184] Referring now to FIGS. 27a, 27b and 27c, another embodiment
of a cushioning element 2701 is shown. Embodiment 2701 includes
cushioning medium 2702, a first set of columns 2703 which are
oriented along a first axis x, a second set of columns 2704 which
are oriented along a second axis y, a third set of columns 2705
which are oriented along a third axis z, column walls 2706 located
between the columns, cavities 2707 formed within the column walls
and an outer periphery 2708. As an example, axis x is perpendicular
to both axis y and axis z and axis y is perpendicular to axis z.
Columns 2703 and 2704, 2703 and 2705, and/or 2704 and 2705 may
intersect each other, as in embodiments 2501 and 2601.
Alternatively, none of the columns may intersect any other column.
The spacing and pattern with which each set of columns is
positioned and the number of cavities 2706 formed within the column
walls 2707 determine the total volume of cushioning medium 2702
within the volume of space occupied by the cushioning element 2701.
As the volume of cushioning medium 2702 within the volume of space
occupied by the cushioning element 2701 decreases, the cushion
becomes lighter and easier to compress. Thus, the spacing and
pattern of each set of columns may be varied to provide a cushion
of desired weight and compressibility. Similarly, the size and
spacing of the cavities 2706 within the column walls 2707 may also
be varied to provide a cushion of desired weight and
compressibility. Cushioning elements which have only two sets of
columns are also within the scope of embodiment 2701.
[0185] FIG. 28 illustrates yet another embodiment of a cushioning
element 2801, which has a contoured upper surface. The cushion 2801
shown in FIG. 28 has columns 2803 and 2804 of different heights and
column walls 2805 and 2806 of different heights. However, a
contoured cushion according to embodiment 2801 could include
columns and column walls having any number of different heights.
Embodiment 2801 also includes cushioning medium 2802 and an outer
periphery 2807. The variability of column and column wall height in
embodiment 2801 imparts the cushion with areas having different
compressibility and firmness characteristics.
[0186] As seen in FIG. 28, cushion 2801 has two distinct levels of
columns. The adjacent longer columns 2803 are grouped together,
referred to as a set of isolated columns 2808. The shorter columns
2804, which are located between sets 2808, tie cushion 2801
together and form a cushion base 2809.
[0187] As an example of the use of cushion 2801, a cushioned object
which comes into contact with the top surface thereof will first
compress columns 2803, causing the column walls 2805 to buckle. The
free area between isolated column sets 2808 enhances the
bucklability of columns 2803. In other words, columns 2803 buckle
more easily than would columns of the same size, separated by
column walls of the same thickness and made from the same material
in a cushion having columns of only one general height. If the load
of the cushioned object causes complete buckling of columns 2803,
columns 2804, which have a greater resistance to buckling than the
long columns, provide a secondary cushioning effect, which is more
like that of a cushion with columns of one general length.
[0188] Referring now to FIG. 29, a cushion 2901 is shown which
includes a cushioning medium 2902, columns 2903, column walls 2904,
and an outer periphery 2905. Cushioning medium includes a plurality
of cells 2906.times., 2906b, 2906c, etc. which are filled with gas
or another cushioning medium. The cushion 2901 depicted in FIG. 29
has open cells 2906. Alternatively, cushion 2901 may have only
closed cells or a combination of open and closed cells. Cells
2906x, 2906b, 2906c, etc. may be of any size and may be dispersed
throughout cushioning medium at any density or concentration that
will provide the desired cushioning and weight characteristics.
[0189] Referring now to FIGS. 30a and 30b, alternative embodiments
of the cushions 3001 and 3001 which have light weight column walls
3004 and 3004', respectively, are shown. Cushions 3001 and 3001'
also include a cushioning medium 3002 and 3002', columns 3003 and
3003' and an outer periphery 3005 and 3005', respectively. Column
walls 3004 and 3004' each include a matrix 3006 and 3006',
respectively, within which are located several voids 3007x, 3007b,
3007c, etc. and 3007.times.', 3007b', 3007c', etc. and 3008a,
3008b, etc., respectively. Matrix 3006 is made from cushioning
medium 3002, 3002'. Voids 3007, 3007', 3008 are hollow areas formed
within matrix 3006 which lighten column walls 3004, 3004'. As
example, voids 3007, 3007' are filled with gas or any other
substance which has a density (i.e., specific gravity) less than
that of cushioning medium 3002, 3002'. As an example, voids 3007,
3007' are open celled (i.e., continuous with the outer surface of
cushion 3001, 3001' and exposed to the atmosphere).
[0190] FIG. 30a shows cushion 3001, the column walls 3004 of which
include a matrix 3006 which forms voids 3007.times., 3007b, 3007c,
etc. having a multi-sided irregular shape. Column walls which have
matrices and pits of other configurations are also within the scope
of the cushioning elements. Embodiment 3001 may be formed by
removal or destruction of volume occupying objects which are
dispersed throughout the cushioning medium as cushion 3001 is
formed.
[0191] FIG. 30b shows cushion 3001 having a matrix 3006 formed from
randomly oriented short tubes 3009a, 3009b, 3009c, etc. which forms
voids 3007 and 3008. Voids 3007a, 3007b', 3007c', etc. are formed
within short tubes 3009a, 3009b, 3009c, etc. and are generally
cylindrical in shape. Matrix 3006' also includes irregularly shaped
secondary voids 3008a, 3008b, 3008c, etc. which are formed by the
exterior surfaces of tubes 3009 between adjacent tubes.
[0192] It is contemplated that the hollow portion of the column
will typically be of uniform cross section throughout its length,
but this is not necessary for all embodiments. For example, in a
column having a circular cross section orthogonal to its
longitudinal axis, the diameter of the circle could increase along
its length, and adjacent columns could correspondingly decrease
along their length (i.e. the columns would be formed as opposing
cones). As another example, the column walls could all thicken from
one cushion surface to another to facilitate the use of tapered
cores (which create the hollow portion of the columns) in the
manufacturing tool, which tapering facilitates the removal of the
cores from the gel.
[0193] As an example the columns of the cushioning element be open
at their top and bottom. However, the columns can be bonded to or
integral with a face sheet on the top or bottom or both, over all
or a portion of the cushion. Or the columns can be interrupted by a
sheet of gel or other material at their midsection which is like a
face sheet except that it cuts through the interior of a cushioning
element.
[0194] In an example embodiment of the cushioning element the
column walls are not perforated. However, perforated walls and/or
face sheets are within the scope hereof. The perforation size and
density can be varied by design to control column stiffness,
buckling resistance, and weight, as well as to enhance air
circulation.
[0195] Wall thickness of the columns can be approximately equal
throughout the cushioning, element for uniformity, but in special
applications of the cushion, wall thickness may be varied to
facilitate manufacturing or to account for differing expected
weight loads across the cushion or for other reasons.
[0196] Typical cushions in the art are ordinarily one piece, but
the cushion can be constricted from more than one discontinuous
cushioning element. For example, three one-inch thick cushions
hereof can be stacked to make a three-inch thick cushion hereof,
with or without other materials between the layers, and with or
without connecting the three layers to one another.
[0197] The cushioning element hereof can be used alone or with a
cover. A cover can be desirable when used to cushion a human body
to mask the small pressure peaks at the edges of the column walls.
This is not necessary if the gel used is soft enough to eliminate
these effects, but may be desirable if firmer gels are used. Covers
can also be desirable to keep the gel (which can tend to be sticky)
clean. If used, a cover should be pliable or stretchable so as not
to overly reduce the gross cushioning effects of the columns
compressing and/or buckling. A cover would also permit air to pass
through it to facilitate air circulation under the cushioned
object.
[0198] While it is envisioned that the immediate application of the
cushion is to cushion human beings (e.g;., seat cushions,
mattresses, wheelchairs cushions, stadium seats, operating table
pads, etc.), Applicant also anticipates that other objects,
including without limitation, animals (e.g. between a saddle and a
horse), manufactured products (e.g., padding between a manufactured
product and a shipping container), and other objects may also be
efficiently cushioned.
[0199] As an example, the columns in the cushion are oriented with
their longitudinal axis generally parallel to the direction of
gravity so that they will buckle under load from a cushioned object
rather than collapse from side pressure. Some type of wall or
reinforcement may be provided about the periphery of the cushioning
element in order to add stability to the cushioning element and in
order to ensure that the buckling occurs in order to decrease
column length under a cushioned object.
[0200] The cushioning element may be described as a gelatinous
elastomeric or gelatinous visco-elastomeric material (i.e. gel)
configured as laterally connected hollow vertical columns which
elastically sustain a load up to a limit, and then buckle beyond
that limit. This produces localized buckling in a cushioning
element beneath a cushioned object depending upon the force placed
upon the cushioning element in a particular location. As a result,
protruding portions of the cushioned object can protrude into the
cushion without being subjected to pressure peaks. As a result, the
cushioning element distributes its supportive pressure evenly
across the contact area of the cushioned object. This also
maximizes the percentage of the surface area of the cushioned
object that is in contact with the cushion.
[0201] Each individual column wall can buckle, markedly reducing
the load carried by that column and causing each column to be able
to conform to protuberances of the cushioned object. Buckling may
be described as the localized crumpling of a portion of a column,
or the change in primary loading of a portion of a column from
compression to bending. In designing structural columns, such as
concrete or steel columns for buildings or bridges, the designer
seeks to avoid buckling because once a column has buckled, it
curves. Far less load than when not buckled. In the columns of this
cushion, however, buckling works to advantage in accomplishing the
objects. The most protruding parts of the cushioned object cause
the load on the columns beneath those protruding parts to have a
higher than average load as the object initially sinks into the
cushion. This higher load causes the column walls immediately
beneath the protruding portion of the cushioned object to buckle,
which markedly reduces the load on the protruding portion. The
surrounding columns, which have not exceeded the buckling
threshold, take up the load which is no longer carried by the
column(s) beneath the most protruding portion of the cushioned
object.
[0202] As an example of the desirability of the buckling provided
by the cushioning element, consider the dynamics of a seat cushion.
The area of a seated person which experiences the highest level of
discomfort when seated without a cushion (such as on a wooden
bench) or on a foam cushion is the tissue that is compressed
beneath the most protruding bones (typically the ischial
tuberosities). When the cushioning element is employed, the area
beneath the protruding portions will have columns that buckle, but
the remainder of the cushioning element should have columns (which
are beneath the broad, fleshy non-bony portion of the person's
posterior) which will withstand the load placed on them and not
buckle. Since the broad fleshy area over which the pressure is
substantially equal is approximately 95% of the portion of the
person subjected to sitting pressure, and the area beneath the
ischial tuberosity is subjected to less than average pressure due
to the locally buckled gel columns (in approximately 5% of that
area), the person is well supported and the cushion is very
comfortable to sit on.
[0203] As another example, the cushioning element is useful in a
bed mattress. The shoulders and hips of a person lying on his/her
side would buckle the columns in the cushioning element beneath
them, allowing the load to be picked up in the less protruding
areas of the person's body such as the legs and abdomen. A major
problem in prior art mattress cushions is that the shoulders and
hips experience too much pressure and the back is unsupported
because the abdomen receives too little pressure. The cushion
hereof offers a solution to this problem by tending, to equalize
the pressure load through local buckling under protruding body
parts.
[0204] The square columns of FIG. 7 or 8 in the cushion are
believed by Applicant to have the best balance between lateral
stability (resistance to collapse from side loads) and light weight
(which also corresponds to good air circulation and low thermal
transfer). Some other types of columns, such those depicted in the
other figures or mentioned elsewhere herein, have more cushioning
media (typically gel) per cubic inch of cushion for a given level
of cushioning support. Thus, the resulting cushions are heavier and
have a higher rate of thermal transfer. They are also more costly
to manufacture due to the increased amount of cushioning media
required. However, columns with oval, circular or triangular cross
sections can be used for some cushioning applications because they
have a greater degree of lateral stability than square or honeycomb
columns since triangles form a braced structure and circles and
ovals form structurally sound arches when considered from a lateral
perspective. Honeycomb columns such as those shown in FIGS. 2, 4,
5, 7, 8, 9 and 10 generally have the least gel per cubic inch of
cushion for a given level of support, but have little lateral
stability.
[0205] The cushions hereof differ from prior art gel cushions in
that, while prior art gel cushions come in a variety of shapes,
many are essentially a solid mass. When a cushioned object attempts
to sink into a prior art gel cushion, the cushion either will not
allow the sinking in because the non-contact portions of the
cushion are constrained from expanding, or the cushion expands
undesirably by pushing gel away from the most protruding parts of
the cushioned object in a manner which tends to increase the
reactive force exerted by the gel against areas of the cushioned
object which surround the protrusions. In the cushion hereof, the
gel has enough hollow space to allow sinking in without expanding
the borders of the cushion, so the problem is alleviated.
[0206] Another problem with many prior art gel cushions is their
weight. For example, a wheelchair cushion made of prior art gel
with dimensions of 18".times.16".times.3.5" would weigh 35-40
pounds, which is unacceptable to many wheelchair users. A cushion
having the same dimensions would weigh approximately seven pounds
or less. To be an acceptable weight for wheelchairs, a typical
prior art wheelchair gel cushion is made only 1" thick. To prevent
bottoming out through such a thin cushion, the makers increase the
rigidity of the gel, which decreases the gel's semi-hydrostatic
characteristics, ruining the gel's ability to equalize pressure.
Thus, many thin gel cushions relieve pressure no better than a foam
cushion. The cushion can be a full 3.5 inches thick needed to allow
sinking in for a human user which is in turn needed to equalize
pressure and increase the surface area under pressure, while still
being light weight.
[0207] The cushions hereof differ from prior art honeycomb cushions
in part in that gel is used instead of thermoplastic film or
thermoplastic elastomer film. Also, a comparatively thick gel is
used for the walls of the columns, as compared to very thin films
made of comparatively much more rigid thermoplastic film or
thermoplastic elastomer film. If thick walls were used in prior art
honeycomb cushions, the rigidity of available thermoplastics and
available thermoplastic elastomers would cause the cushion to be
far too stiff for typical applications. Also, the use of
comparatively hard, thin walls puts the cushioned object at
increased risk. When the load on a prior art honeycomb cushion
exceeds the load carrying capability of virtually all of the
columns (i.e., they all buckle), the cushioned object bottoms out
onto a relatively hard, rigid, thin pile of thermoplastic film
layers. In that condition, the cushioned object is subjected to
pressures similar to the pressures it would experience with no
cushion at all. The cushioned object is thus at risk of damaging
pressures on its most protruding portions.
[0208] In comparison, if the same bottoming out occurs on the
cushion hereof, the most protruding portions of the cushioned
object would be pressed into a pile of relatively thick, soft gel
layers, which would add up to typically 20% of the original
thickness of the cushion. Thus, the risk of bottoming, out is
substantially lowered.
[0209] Another difference between prior art thermoplastic honeycomb
cushions and the cushion hereof is that the configuration of the
cushion is not limited to honeycomb columns, but can take advantage
of the varying properties offered by columns of virtually any cross
sectional shape. The prior art thermoplastic honeycomb cushions are
so laterally unstable that at least one face sheet must be bonded
across the open cells. This restricts the air circulation, which is
only somewhat restored if small perforations are made in the face
sheet or cells. While face sheets and perforations are an option on
the cushions hereof, the alternative cross sectional shapes of the
columns (e.g., squares or triangles) make face sheets unnecessary
due to increased lateral stability and thus perforations are
unnecessary since both ends of the configuration of the column can
be open to the atmosphere.
[0210] The maximum thickness of the walls of the columns of the
cushion hereof should be such that the bulk density of the cushion
is less than 50% of the bulk density if the cushion were completely
solid gel. Thus, at least 50% of the volume of space occupied by
the cushioning element is occupied by a gas such as air and the
remainder is occupied by gel. The minimum thickness of the walls of
the columns is controlled by three factors: (1) manufacturability;
(2) the amount of gel needed for protection of the cushioned object
in the event of all columns buckling; and (3) the ability to
support the cushioned object without buckling the majority of the
columns. The thickness would be such that the columns under the
most protruding parts of the cushioned object are buckled, and the
remaining columns are compressed in proportion to the degree of
protrusion of the cushioned object immediately above them but are
not buckled.
[0211] Cushion Materials
[0212] The cushioning media used to manufacture the cushioning
element can soft gel. This; assures that the cushion will yield
under a cushioned object by having buckling columns and by the
cushioning medium itself compressing under the weight of the
cushioned object. The soft gel will provide additional cushioning
and will accommodate uneven surfaces of the cushioned object.
Nevertheless, firmer gels are also useful in the cushioning
element, provided that the gel is soft enough to provide acceptable
cushioning for the object in the event that all of the columns
buckle. Since, with a given type of gel, there is typically a
correlation between softness and Young's modulus (stiffness) (i.e.,
a softer gel is less stiff), and since there is a correlation
between Young's modulus and the load carrying capability of a
column before buckling, there is typically a need for firmer gels
in cushions which will carry a higher load. However, there are
other alternatives for increasing a cushion's load carrying
capability, such as increasing the column wall thickness, so that
the softness of the gel can be selected for its cushioning
characteristics and not solely for its load bearing
characteristics, particularly in cases where cushion weight is not
a factor. Any gelatinous elastomer or gelatinous visco-elastomer
with a hardness on the Shore A scale of less than about 15 is
useful in the cushioning element. The cushioning medium can have a
Shore A hardness of about 3 or less. Or materials which have a
hardness of less than about 800 gram bloom can be used. Such
materials are too soft to measure on the Shore A scale. Gram Bloom
is defined as the gram weight required to depress a gel a distance
of four millimeters (4 mm) with a piston having a cross-sectional
area of one square centimeter (1 cm) at a temperature of about
23.degree. C. The example gel may be cohesive at the normal useable
temperatures of a cushioning element. The example gel will not
escape from the cushioning element if the cushioning element is
punctured. The example gel has shape memory so that it tends to
return to its original shape after deformation.
[0213] The cushioning media or gel should also be strong enough to
withstand the loads and deformations that are ordinarily expected
during the use of a cushion. For a given type of gel, there is
typically a correlation between softness and strength (i.e., softer
gels are not as strong as harder gels).
[0214] Because of their high strength even in soft formulations,
their low cost, their ease of manufacture, the variety of
manufacturing methods which can be used, and the wide range of
Young's modulus which can be formulated while maintaining the
hydrostatic characteristics of a gel, the gel formulations which
follow are example gels to be used in cushions.
[0215] Applicant believes that the reader might benefit from a
general background discussion of the chemistry underlying the gels
prior to reading about the example formulations.
Chemistry of Plasticizer-Extended Elastomers
[0216] A basic discussion of the chemical principles underlying the
characteristics and performance of plasticizer-extended elastomers
is provided below to orient the reader for the later discussion of
the particular chemical aspects of the material for use in the
cushions.
[0217] The example gel cushioning medium is a composition primarily
of triblock copolymers and plasticizers, both of which are commonly
referred to as hydrocarbons. Hydrocarbons are elements which are
made up mainly of Carbon (C) and Hydrogen (H) atoms. Examples of
hydrocarbons include gasoline, oil, plastic and other petroleum
derivatives.
[0218] Referring to FIG. 31a, it can be seen that a carbon atom
3110 typically has four covalent bonding sites ".cndot.". FIG. 31b
shows a hydrogen atom 3112, which has only one covalent bonding
site .cndot.. With reference to FIG. 31c, which represents a
four-carbon molecule called butane, a "covalent" bond, represented
at 3116 as "-", is basically a very strong attraction between
adjacent atoms. More specifically, a covalent bond is the linkage
of two atoms by the sharing of two electrons, one contributed by
each of the atoms. For example, the first carbon atom 3118 of a
butane molecule 3114 shares an electron with each of three hydrogen
atoms 3120, 3122 and 3124, represented as covalent bonds 3121, 3123
and 3125, respectively, accounting for three of carbon atom 3118's
available electrons. The final electron is shared with the second
carbon atom 3126, forming covalent bond 3127. When atoms are
covalently bound to one another, the atom-to-atom covalent bond
combination makes up a molecule such as butane 3114. An
understanding of hydrocarbons, the atoms that make hydrocarbons and
the bonds that connect those atoms is important because it provides
a basis for understanding the structure and interaction of each of
the components of the example gel material.
[0219] As mentioned above, the example gel cushioning material
utilizes triblock copolymers. With reference to FIGS. 32a and 32b,
a triblock copolymer is shown. Triblock copolymers 3210 are so
named because they each have three blocks-two endblocks 3212 and
3214 and a midblock 3216. If it were possible to grasp the ends of
a triblock copolymer molecule and stretch them apart, each triblock
copolymer would have a string-like appearance (as in FIG. 32a),
with an endblock being located at each end and the midblock between
the two endblocks.
[0220] FIG. 33a depicts the example endblocks of the copolymer most
example for use in the example gel material, which are known as
monoalkenylarene polymers 3310. Breaking the term
"monoalkenylarene" into its component parts is helpful in
understanding the structure and function of the endblocks. "Aryl"
refers to what is known as an aromatic ring bonded to another
hydrocarbon group. Referring now to FIG. 33b, benzene 3312, one
type of aromatic ring, is made up of six carbon molecules 3314,
3316, 3318, 3320, 3322 and 3324 bound together in a ring-like
formation. Due to the ring structure, each of the carbon atoms is
bound to two adjacent carbon atoms. This is possible because each
carbon atom has four bonding sites. In addition, each carbon atom C
of a benzene molecule is bound to only one hydrogen atom H. The
remaining bonding site on each carbon atom C is used up in a double
covalent bond 3326, 3327, which is referred to as a double bond.
Because each carbon atom has only four bonding sites, double
bonding in an aromatic ring occurs between a first carbon and only
one of the two adjacent carbons. Thus, single bonds 3116 and double
bonds 3326 alternate around the benzene molecule 3312. With
reference to FIG. 33c, in an aryl group 3328, one of the carbons
3330 is not bound to a hydrogen atom, which frees up a bonding site
R for the aryl group to bond to an atom or group other than a
hydrogen atom.
[0221] Turning now to FIG. 33d, "alkenyl" 3332 refers to a
hydrocarbon group made up of only carbon and hydrogen atoms,
wherein at least one of the carbon-to-carbon bonds is a double bond
3334 and the hydrocarbon group is connected to another group of
atoms R', where R' represents the remainder of the hydrocarbon
molecule and can include a single hydrogen atom. Specifically, the
"en" signifies that a double bond is present between at least one
pair of carbons. The "yl" means that the hydrocarbon is attached to
another group of atoms. For example, FIG. 33e shows a two carbon
group having a double bond between the carbons, which is called
etheny13336. Similarly, FIG. 3f illustrates a three carbon group
having a double bond between two of the carbons, which is called
propenyl 3338. Referring again to FIG. 33a, in a monoalkenylarene
such as styrene, a carbon 3340 with a free bonding site of an
alkenyl group 3332 is bonded to the aryl group 3328 at carbon atom
3330, which also has a free bonding site. In reference to FIG. 33c,
aryl group 3328 is part of a monoalkenylarene molecule when R is an
alkenyl group. The "mono" of monoalkenylarene explains that only
one alkenyl group is bonded to the aryl group.
[0222] The monoalkenylarene end blocks of a triblock copolymer are
polymerized. Polymerization is the process whereby monomers are
connected in a chain-like fashion to form a polymer. FIG. 34a
depicts a polymer 3410, which is basically a large chain-like
molecule formed from many repeating smaller molecules, called
monomers, M1, M2, M3, etc., that are bonded together. P and P'
represent the ends of the polymer, which are also made up of
monomers FIG. 34b illustrates a monoalkenylarene end block polymer
3414, which is a chain of monoalkenylarene molecules 3416a, 3416b,
3416c, etc. The chain of FIG. 34b is spiral, or helical, in shape
due to the bonding angles between styrene molecules. P represents
an extension of the endblock polymer helix in one direction, while
P' represents an extension of the endblock polymer helix in the
opposite direction.
[0223] As FIG. 34c shows, monoalkenylarene molecules are attracted
to one another by a force that is weaker than covalent bonding. The
primary weak attraction between monoalkenylarene molecules is known
as hydrophobic attraction. An example of hydrophobic attraction is
the attraction of oil droplets to each other when dispersed in
water. Therefore, in its natural, relaxed state at room
temperature, a monoalkenylarene polymer resembles a mass of
entangled string 3414, as depicted in FIG. 34d. The attraction of
monoalkenylarene molecules to one another creates a tendency for
the endblocks to remain in an entangled state. Similarly, different
monoalkenylarene polymers are attracted to each other. The
importance of this phenomenon will become apparent later in this
discussion.
[0224] Like the end blocks of a triblock copolymer, the midblock is
also a polymer. The example triblock copolymer for use in the
elastomer component of the example cushioning medium includes is an
aliphatic hydrocarbon midblock polymer. Traditionally, "aliphatic"
meant that a hydrocarbon was "fat like" in its chemical behavior.
Referring to FIGS. 35a through 35c, which, for simplicity, do not
show the hydrogen atoms, an "aliphatic compound" is now defined as
a hydrocarbon compound which reacts like an alkane 3510 (a
hydrocarbon molecule having only single bonds between the carbon
atoms), an alkene 3512 (a hydrocarbon molecule wherein at least one
of the carbon-to-carbon bonds is a double bond) 3514, an alkyne (a
hydrocarbon molecule having a triple covalent bond 3515 between at
least one pair of carbon atoms), or a derivative of one or a
combination of the above.
[0225] Referring now to FIG. 35d, which omits the bound hydrogen
atoms for simplicity, aliphatic hydrocarbons known as conjugated
dienes 3516 are depicted. These are the example midblock monomers
used in the triblock copolymers of the example gel material. A
"diene" is a hydrocarbon molecule having two ("di") double bonds
("ene"). "Conjugated" means that the double bonds 3518 and 3520 are
separated by only one single carbon-to-carbon bond 3522. In
comparison, FIG. 35e shows a hydrocarbon molecule having two double
carbon-to-carbon bonds that are separated by two or more single
bonds, 3530, 3532, etc., which is referred to as an "isolated
diene" 3524. When double bonds are conjugated, they interact with
each other, providing greater stability to a hydrocarbon molecule
than would the two double bonds of an isolated diene.
[0226] FIGS. 36a through 36d illustrate examples of various
monomers useful in the midblock of the triblock copolymers example
for use in the elastomer component of the example gel cushioning
medium, including molecules (monomers) such as ethylene-butylene
(EB) 3612, ethylene-propylene (EP) 3614, butadiene (B) 3616 (either
hydrogenated or non-hydrogenated) and isoprene (I) 3618 (either
hydrogenated or non-hydrogenated). The different structures of
these molecules provide them with different physical
characteristics, such as differing strengths of covalent bonds
between adjacent monomers. The various structures of monomer
molecules also provides for different types of interaction between
distant monomers on the same chain (e.g., when the midblock chain
folds back on itself, distant monomers may be attracted to one
another by a force weaker than covalent bonding, such as
hydrophobic interaction, hydrophilicinteraction, polar forces or
Vander Waals forces).
[0227] Referring to FIGS. 36a and 36b, x, y and n each represent an
integral number of each bracketed unit: "x" is the number of
repeating ethylene (--CH2--CH2--) units, "y" is the number of
repeating butylene (in FIG. 36a) or propylene (in FIG. 36b) units,
and "n" is the number of repeating poly(ethylene/butylene) units.
Numerous configurations are possible. As shown in FIGS. 37a through
37d, the midblock may contain (i) only one type of monomer, EB, EP,
B or I or, as FIGS. 37e and 37f illustrate, (ii) a combination of
monomer types EB and EP or B and 1, providing for wide variability
in the physical characteristics of different midblocks made from
different types or combination of types of monomers. The
interaction of physical characteristics of each molecule (monomer
and block) determines the physical characteristics of the tangible,
visible material. In other words, the type or types of monomer
molecules which make up the midblock polymer play a role in
determining various characteristics of the material of which the
midblock is a part.
[0228] Attributes such as strength, elongation, elasticity or
visco-elasticity, softness, tackiness and plasticizer retention
are, in part, determined by the type or types of midblock monomers.
For example, referring again to FIG. 37a, the midblock polymer 3216
of a triblock copolymer containing material may be made up
primarily or solely of ethylene-butylene monomers EB, which
contribute to that material's physical character. With reference to
FIG. 37e, in comparison to the material having a midblock made up
solely of EB, a similar triblock containing material, wherein the
midblock polymer 3216 of the triblocks are made up of a combination
of butadiene B and isoprene I monomers, may have greatly increased
strength and elongation, similar elasticity or visco-elasticity and
softness, reduced tackiness and reduced plasticizer bleed.
[0229] The monomer units of the midblock have an affinity for each
other. However, the hydrophobic attraction of the midblock monomers
for each other is much weaker than the non-covalent attraction of
the end block monomers for one another.
[0230] Referring now to FIG. 38a, which shows a
polystyrene-poly(butadiene- +isoprene) polystyrene triblock
copolymer, in a complete triblock copolymer 3810, each end 3812 and
3814 of midblock chain 3216 is covalently bound to an end block
3212 and 3214. P and P" represent the remainder of the endblock
polymers 3212 and 3214 respectively. P' represents the central
portion of midblock polymer 3216. Many billions of triblock
copolymers combine to form a tangible material. The triblock
copolymers are held together by the high affinity (i.e.,
hydrophobic attraction) that monoalkenylarene molecules have for
one another. In other words, as FIG. 38b illustrates, the endblocks
of each triblock copolymer molecule, each of which resemble an
entangled mass of string 3414, are attracted to the endblocks of
another triblock copolymer. When several endblocks are attracted to
each other, they form an accretion of endblocks, called a domain or
a glassy center 3816. Agglomeration of the endblocks occurs in a
random fashion, which results in a three-dimensional network 3818
of triblocks, the midblock 3216 of each connecting endblocks 3212
and 3214 located at two different domains 3816a and 3816b. In
addition to holding the material together, the domains of triblock
copolymers also provide it with strength and rigidity.
[0231] Plasticizers are generally incorporated into a material to
increase the workability, pliability and flexibility of that
material. Incorporation of plasticizers into a material is known as
plasticization. Chemically, plasticizers are hydrocarbon molecules
which associate with the material into which they are incorporated,
as represented in FIG. 39a. In the example gel material,
plasticizer molecules 3910 associate with the triblock copolymer
3210, and increase its workability, softness, elongation and
elasticity or visco-elasticity. Depending upon the type of
plasticizer used, the plasticizer molecules associate with either
the endblocks, the midblock, or both. In order to preserve the
strength of the example gel materials, Applicant prefers the
predominant use of plasticizers 3910 which associate primarily with
midblock polymer 3216 of triblock copolymer 3818, rather than with
the end blocks. However, plasticizers which associate with the end
blocks may also be useful in some formulations of the example gel
material. Plasticizers are also desired which associate with the
principle thermoplastic polymer component of the gel material.
[0232] Chemists have proposed four general theories to explain the
effects that plasticizers have on certain materials. These theories
are known as the lubricity theory, the gel theory, the mechanistic
theory and the free volume theory.
[0233] The lubricity theory, illustrated in FIGS. 39b through 39d,
assumes that the rigidity of a material (i.e., its resistance to
deformation) is caused by intermolecular friction. Under this
theory, plasticizer molecules 3910 lubricate the large molecules,
facilitating movement of the large molecules over each other. See
generally, Jacqueline 1. Kroschwitz, ed., CONCISE ENCYCLOPEDIA OF
POLYMER SCIENCE AND ENGINEERING 734-44, Plasticizers (1990), which
is hereby incorporated by reference. In the case of triblock
copolymers, lubrication of the endblocks should be avoided since
the endblock domains are responsible for holding the triblock
copolymers together and impart the material with strength (e.g.,
tensile strength during elongation). Thus, a plasticizer which
associates with the midblocks is example. According to the
lubricity theory, when manipulative force is exerted on the
material, plasticizer 3910 facilitates movement of midblocks 3216
past each other. Id. at 734-35. The arrows in FIGS. 39b, 39c and
39d represent the motion of midblocks 3216 with respect to each
other. FIG. 39b represents adjacent midblocks being pulled away
from each other. FIG. 39c represents two midblocks being forced
side-to-side. FIG. 39d represents adjacent midblocks being pulled
across one another.
[0234] FIGS. 39e and 39f depict a second plasticization theory, the
gel theory, which reasons that the resistance of amorphous polymers
to deformation results from an internal, three dimensional
honeycomb structure or gel. Loose attachments between adjacent
polymer chains, which occur at intervals along the chains, called
attachment points, form the gel. Closer attachment between adjacent
chains creates a stiffer and more brittle material. Plasticizers
3910 break, or solvate, the points of attachment 3914 between
polymer chains, loosening the structure of the material. Thus,
plasticizers produce about the same effect on a material as if
there were fewer attachment points between polymer chains, making
the material softer or less brittle. See Id. at 735. Since one of
the purposes of the example gel is to provide a material which does
not have significantly decreased tensile strength, which is
provided by agglomeration of the endblocks, according to the gel
theory plasticizer 3910 should associate with midblocks 3216 rather
than with the endblocks. Further, a plasticizer which associates
with the midblock polymers decreases the attachment of adjacent
midblocks, which likely decreases the rigidity while increasing the
pliability, elongation and elasticity or visco-elasticity of the
material. Similar to the lubricity theory, under the gel theory,
reduction of attachment points between adjacent midblocks
facilitates movement of the midblocks past one another as force is
applied to the material.
[0235] Referring now to FIG. 39g, the mechanistic theory of
plasticization assumes that different types of plasticizers 3910,
3912, etc. are attracted to polymer chains by forces of different
magnitudes. In addition, the mechanistic theory supposes that,
rather than attach permanently, a plasticizer molecule attaches to
a given attachment point only to be later dislodged and replaced by
another plasticizer molecule. This continuous exchange of
plasticizers 3910, 3912, etc., demonstrated by FIG. 39g as
different stages connected by arrows which represent an equilibrium
between each stage, is known as a dynamic equilibrium between
solvation and desolvation of the attachment points between adjacent
polymer chains. The number or fraction of attachment points
affected by a plasticizer depends upon various conditions, such as
plasticizer concentration, temperature, and pressure. See Id.
Accordingly, as applied to the example gel material, a large amount
of plasticizer would be necessary to affect the majority of
midblock attachment points and thus provide the desired amounts of
rigidity, softness, pliability, elongation and elasticity or
visco-elasticity.
[0236] With reference to FIGS. 39h through 39j, the fourth
plasticization theory, known as the free volume theory, assumes
that there is nothing but free space between molecules. As
molecular motion increases (e.g., due to heat), the free space
between molecules increases. Thus, a disproportionate amount of
that free volume is associated with the ends of the polymer chains.
As FIGS. 39h through 39j demonstrate, free volume is increased by
using polymers with shorter chain lengths. For example, the black
rectangles of FIG. 39h represent a material made up of long
midblock polymers 3216. The white areas around each black rectangle
represent a constant width of free space around the molecule. In
FIG. 39i, a molecule 3916, which is smaller than midblock 3216, is
added to the material, creating more free space. In FIG. 39j, an
even smaller molecule 3918 has been added to the material. The
increase in free space within the material is evident from the
increased area of white space. The crux of the free volume theory
is that the increase in free space or volume allows the molecules
to more easily move past one another. In other words, the use of a
small (or low molecular weight) plasticizer increases the ability
of the midblock polymer chains to move past each other. While FIGS.
39h, 39i and 39j provide a fair representation of the free volume
theory, in reality, the increase in free space would be much
greater than a two-dimensional drawing illustrates since molecules
are three dimensional structures.
[0237] Similarly, the use of polymers with flexible side chains
create additional free volume around the molecule, which produces a
similar plasticization-like effect, called internal plasticization.
Applicant believes that incorporation of monomers into the
midblock, which create flexible side chains thereon, including but
not limited to isoprene (either hydrogenated or non-hydrogenated)
and ethylene/propylene monomers, creates internal plasticization.
In compassion, the addition of an even smaller plasticizer
molecule, described above, increases the free space at a given
location; this is external plasticization. The size and shape of
plasticizing molecule and the nature of its atoms and groups of
atoms (i.e., nonpolar, polar, hydrogen bonding or not, and dense or
light) determines the plasticizer's plasticizing ability on a
specific polymer. See Id.
[0238] With this general background in mind, Applicant will explain
the formulation, chemical structure and performance of the example
gel material.
[0239] Definitions
[0240] For the reader's convenience, Applicant has defined several
terms which are used throughout the description of the present gel.
Additionally, other terms have been defined throughout the detailed
description of the example gel material.
Elasticity and Visco-Elasticity
[0241] When finite strains are imposed upon visco-elastic
materials, such as the example gel materials, the stress-strain
relations are much more complicated than those ordinarily
anticipated in accordance with the classical theory of elasticity
(Hooke's law) or the classical theory of hydrodynamics (Newton's
law). According to Hooke's law, stress is always directly
proportional to strain in small deformations but independent of the
rate of strain or the strain history. Newton's law of
hydrodynamics, which deals with the properties of viscous liquids,
states that stress is always directly proportional to the rate of
strain but independent of the strain itself.
[0242] "Elastic," as defined herein, refers to a characteristic of
materials which return substantially to their original shape
following deformation and the subsequent cessation of deforming
force.
[0243] "Visco-," as defined herein, relates to both the rate of
deformation and the rate of reformation. In reference to
deformation rate, the faster a deforming force is applied to a
visco elastic material, the stiffer it is. The rate of reformation
of a visco-elastic material is slower than that of a truly elastic
material.
[0244] Even if both strain and rate of strain are infinitesimal, a
visco-elastic material may exhibit behavior that combines
liquid-like and solid-like characteristics. For example, materials
that exhibit not-quite-solid-like; characteristics do not maintain
a constant deformation under constant stress but deform, or creep,
gradually over time. Under constant deformation, the stress
required to hold a visco-elastic material in the deformed state
gradually diminishes until it reaches a relatively steady state. On
the other hand, a visco-elastic material that exhibits
not-quite-liquid like characteristics may, while flowing under
constant stress, store some of the energy input instead of
dissipating it all as heat. The stored energy may then cause the
material to at least partially recover from its deformation, known
as elastic recoil, when the stress is removed. When viscoelastic
materials are subjected to sinusoidally oscillating stress, the
strain is neither exactly in phase with the stress (as it would be
for a perfectly elastic solid) nor 90.degree. out of phase (as it
would be for a perfectly viscous liquid), but is somewhere in
between. Visco-elastic materials store and recover some of the
deforming energy during each cycle, and dissipate some of the
energy as heat. If the strain and rate of strain on a visco-elastic
material are infinitesimal, the behavior of that material is linear
viscoelastic and the ratio of stress to strain is a function of
time (or frequency) alone, not of stress magnitude. The gel
material example is elastic in nature. Visco-elastic materials are
also useful in the cushions.
[0245] Rebound Rate
[0246] "Rebound rate", as defined herein, is the amount of time it
takes a one inch long piece of material to rebound to within about
five percent its original shape and size following the release of
stress which elongates the material to a length of two inches. The
example elastic (or elastomenc) gel material useful in the
cushioning elements has a rebound rate of less than about one
second. The example visco-elastic (or visco-elastomeric) gel
material useful in the cushioning elements has a rebound rate of at
least about one second. More preferably, the example visco-elastic
gel has a rebound rate within the range of about one second to
about ten minutes.
[0247] "Instantaneous Rebound," as defined herein, refers to a
characteristic of a one inch long piece of an elastomeric material
which returns substantially to its original size and shape in times
of about one second or less following the release of stress which
elongates the material to a length of two inches. "Elastomer," as
used herein, refers to the gel materials that are useful in the
cushioning element hereof and which have instantaneous rebound.
[0248] "Delayed Rebound," as used herein, refers to a
characteristic of the visco-elastic materials example for use in
the cushions hereof which have a rebound rate of at least about one
second. More preferably, the example visco-elastomeric material has
a rebound rate within the range of about one second to about ten
minutes. "Visco-elastomer," as defined herein, refers to gel
materials useful in the cushions which exhibit delayed rebound
characteristics.
[0249] Resins
[0250] The term "resin" is defined herein as a solid or semisolid
fusible, organic substance that is usually transparent or
translucent, is soluble in organic solvent but not in water, is an
electrical nonconductor, and includes tackifiers. Resins are
complex mixtures which associate together due to similar physical
or chemical properties. Because of their complex nature, resins do
not exhibit simple melting or boiling points.
[0251] "Resinous" as used herein refers to resins and resin-like
materials.
[0252] "Resinous plasticizers" as used herein refers to
plasticizers which include a majority, by weight, of a resin or
resins.
[0253] "Tackifier" as used herein refers to resins that add tack to
the resulting mixture. The primary function of a tackifier is to
add tack. The secondary functions of tackifiers include
modification of both melt viscosity and melt temperature.
[0254] Tackifiers are normally low molecular weight and high glass
transition temperature (Tg) materials, and are sometimes
characterized as highly condensed acrylic structures. The most
commonly used tackifiers are rosin derivatives, terpene resins, and
synthetic or naturally derived petroleum resins. A tackifier's
effectiveness is largely determined by its compatibility with the
rubber component and by its ability to improve the tackiness of a
material.
[0255] "Low molecular weight," as defined herein with reference to
resins, means resins having a weight average molecular weight of
less than about 50,000.
[0256] Resins and tackifiers are used in some example formulations
of the example gel cushioning medium.
[0257] Oils
[0258] The term "oil" is defined herein as naturally occurring
hydrocarbon liquids, the carbons of which are primarily saturated
with hydrogen atoms. Oils example for use in the example gel are
mineral oils.
[0259] "Paraffinic" oils have include straight-chain or
branched-chain structures. "Naphthenic" oils include cyclic
hydrocarbon structures. When an oil contains both paraffinic- and
naphthenic-type structures, the relative concentrations of each
type of structure determine whether the oil is identified as
naphthenic or paraffinic.
[0260] "Oil viscosity" is defined herein as the measurement of time
it takes a given volume of oil to pass through an orifice, such as
a capillary tube. Viscosity measurements include the Saybolt
universal second (SUS), stokes (s) and centistokes (cs).
[0261] Molecular Weight
[0262] "Number Average Molecular Weight" (Mn), as determined by gel
permeation chromatography, provides information about the lower
molecular weight parts of a substance which includes hydrocarbon
molecules.
[0263] "Weight Average Molecular Weight" (MW), as determined by gel
permeation chromatography, indicates the average molecular weight
of hydrocarbon molecules in a substance. This is the value that is
commonly used in reference to the molecular weight of a hydrocarbon
molecule.
[0264] "Z-Average Molecular Weight" (Mz), as determined by gel
permeation chromatography, is used as an indication of the
high-molecular-weight portion of a substance which includes
hydrocarbon molecules. When the substance is a resin, the Z-average
molecular weight indicates the compatibility and adhesive
properties of that resin.
[0265] Molecular weight values may also be determined by any of
several other methods, such as the Flory viscosity method, the
Staudinger viscosity method, light scattering in combination with
high performance liquid chromatography (HPLC, and others.
[0266] Cloud Point Tests
[0267] The following values, which are determined by cloud point
tests, are useful in determining the compatibility of a resin with
different types of materials.
[0268] "MMAP," as defined herein, is a measurement of aromatic
solubility and determines the aliphatic/aromatic character of a
resin. The MMAP value is obtained by dissolving a resin in a high
temperature mixture of one part methylcyclohexane and two parts
aniline, and cooling the solution while mixing to determine the
temperature at which the mixture starts becoming cloudy, which is
commonly referred to as the cloud point. The lower the MMAP value,
the greater the aromaticity and lower the aliphaticity of the
resin.
[0269] "DACP," as defined herein, is a value which determines the
polarity of a resin due to the highly polar nature of the solvent
system. In order to determine the DACP value of resin, the resin
must first be dissolved in a heated 1:1 mixture of xylene and
4-hydroxy-4-methyl-pentanone. The solution its then cooled with
mixing. The temperature at which the solution begins becoming
opaque is the cloud point, which is the DACP value.
[0270] Since specific adhesion is related to the polarity of a
resin, the DACP value can be used as a specific adhesion indicator.
Lower DACP values indicate greater specific adhesion.
[0271] "OMSCP," as defined herein, is a value which is related to
the molecular weight and molecular weight distribution of a resin.
OMSCP can determine the compatibility characteristics of a
resin/polymer system. The higher the OMS cloud point, the greater
the molecular weight and the molecular weight distribution of a
resin. In particular, high OMSCP values can indicate the presence
of high molecular weight materials (of Z-average molecular
weight).
[0272] The term "OMSCI" is derived from the method for determining
OMSCP values. A resin is first dissolved in a high temperature
mixture of odorless mineral spirits (OMS). The solution is then
cooled with mixing. The temperature at which the mixture starts
becoming cloudy is referred to as the cloud point (CP), or OMSCP
value.
[0273] Material Formulations
[0274] Elastomer Component
[0275] Preferably, the compositions of the example gel materials
are low durometer (as defined below) thermoplastic elastomeric
compounds and viscoelastomeric compounds which include a principle
polymer component, an elastomeric block copolymer component and a
plasticizer component.
[0276] The elastomer component of the example gel material includes
a triblock polymer of the general configuration A-B-A, wherein the
A represents a crystalline polymer such as a mono alkenylarene
polymer, including but not limited to polystyrene and
functionalized polystyrene, and the B is an elastomenc polymer such
as polyethylene, polybutylene, poly(ethylene/butylene),
hydrogenated poly(isoprene), hydrogenated poly(butadiene),
hydrogenated poly(isoprene+butadiene), poly(ethylene/propylene) or
hydrogenated poly(ethylene/butylene+ethylene/- propylene), or
others. The A components of the material link to each other to
provide strength, while the B components provide elasticity.
Polymers of greater molecular weight are achieved by combining many
of the A components in the A portions of each A-B-A structure and
combining many of the B components in the B portion of the A-B-A
structure, along with the networking of the A-B-A molecules into
large polymer networks.
[0277] A example elastomer for making the example gel material is a
very high to ultra high molecular weight elastomer and oil compound
having an extremely high Brookfield Viscosity (hereinafter referred
to as "solution viscosity"). Solution viscosity is generally
indicative of molecular weight. "Solution viscosity" is defined as
the viscosity of a solid when dissolved in toluene at 25-30.degree.
C., measured in centipoises (cps). "Very high molecular weight" is
defined herein in reference to elastomers having a solution
viscosity, 20 weight percent solids in 80 weight percent toluene,
the weight percentages being based upon the total weight of the
solution, from greater than about 20,000 cps to about 50,000 cps.
An "ultra high molecular weight elastomer" is defined herein as an
elastomer having a solution viscosity, 20 weight percent solids in
80 weight percent toluene, of greater than about 50,000 cps. Ultra
high molecular weight elastomers have a solution viscosity, 10
weight percent solids in 90 weight percent toluene, the weight
percentages being based upon the total weight of the solution, of
about 800 to about 30,000 cps and greater. The solution
viscosities, in 80 weight percent toluene, of the A-B-A block
copolymers useful in the elastomer component of the example gel
cushioning material are substantially greater than 30,000 cps. The
solution viscosities, in 90 weight percent toluene, of the example
A-B-A elastomers useful in the elastomer component of the example
gel are in the range of about 2,000 cps to about 20,000 cps. Thus,
the example elastomer component of the example gel material has a
very high to ultra high molecular weight.
[0278] Applicant has discovered that, after surpassing a certain
optimum molecular weight range, some elastomers exhibit lower
tensile strength than similar materials with optimum molecular
weight copolymers. Thus, merely increasing the molecular weight of
the elastomer will not always result in increased tensile
strength.
[0279] The elastomeric B portion of the example A-B-A polymers has
an exceptional affinity for most plasticizing agents, including but
not limited to several types of oils, resins, and others. When the
network of A-B-A molecules is denatured, plasticizers which have an
affinity for the B block can readily associate: with the B blocks.
Upon renaturation of the network of A-B-A molecules, the
plasticizer remains highly associated with the B portions, reducing
or even eliminating plasticizer bleed from the material when
compared with similar materials in the prior art, even at very high
oil:elastomer ratios. The reason for this performance may be any of
the plasticization theories explained above (i.e., lubricity
theory, gel theory, mechanistic theory, and free volume
theory).
[0280] The elastomer used in the example gel cushioning medium is
preferably an ultra high molecular weight polystyrene-hydrogenated
poly(isoprene+butadiene)-polystyrene, such as those sold under the
brand names SEPTON 4045, SEPTON 4055 and SEPTON 4077 by Kuraray, an
ultra high molecular weight polystyrene-hydrogenated
polyisoprene-polystyrene such as the elastomers made by Kuraray and
sold as SEPTON 2005 and SEPTON 2006, or an ultra high molecular
weight polystyrene-hydrogenated polybutadiene-polystyrene, such as
that sold as SEPTON 8006 by Kuraray. High to very high molecular
weight polystyrene-hydrogenated
poly(isoprene+butadiene)-polystyrene elastomers, such as that sold
under the trade name SEPTON 4033 by Kuraray, are also useful in
some formulations of the example gel material because they are
easier to process than the example ultra high molecular weight
elastomers due to their effect on the melt viscosity of the
material.
[0281] Following hydrogenation of the midblocks of each of SEPTON
4033, SEPTON 4045, SEPTON 4055, and SEPTON 4077, less than about
five percent of the double bonds remain. Thus, substantially all of
the double bonds are removed from the midblock by
hydrogenation.
[0282] Applicant's most example elastomer for use in the example
gel is SEPTON 4055 or another material that has similar chemical
and physical characteristics. SEPTON 4055 has the optimum molecular
weight (approximately 300,000, as determined by Applicant's gel
permeation chromatography testing). SEPTON 4077 has a somewhat
higher molecular weight, and SEPTON 4045 has a somewhat lower
molecular weight than SEPTON 4055. Materials which include either
SEPTON 4045 or SEPTON 4077 as the primary block copolymer typically
have lower tensile strength than similar materials made with SEPTON
4055.
[0283] Kuraray Co. Ltd. of Tokyo, Japan has stated that the
solution viscosity of SEPTON 4055, the most example A-B-A triblock
copolymer for use in the example gel material, 10% solids in 90%
toluene at 25.degree. C., is about 5,800 cps. Kuraray also said
that the solution viscosity of SEPTON 4055, 5% solids in 95%
toluene at 25.degree. C., is about 90 cps. Although Kuraray has not
provided a solution viscosity, 20% solids in 80% toluene at
25.degree. C., an extrapolation of the two data points given shows
that such a solution viscosity would be about 400,000 cps.
Applicant reads the prior art as consistently teaching away from
such high solution viscosities.
[0284] Applicant confirmed Kuraray's data by having an independent
laboratory, SGS U.S. Testing Company Inc. of Fairfield, N.J., test
the solution viscosity of SEPTON 4055. When SGS attempted to
dissolve 20% solids in 80% toluene at 25.degree. C., the resulting
material did not resemble a solution. Therefore, SGS determined the
solution viscosity of SEPTON 4055 using 10% solids in 90% toluene
at 25.degree. C., which resulted in a 3,040 cps solution.
[0285] Other materials with chemical and physical characteristics
similar to those of SEPTON 4055 include other A-B-A triblock
copolymers which have a hydrogenated midblock polymer that is made
up of at least about 30% isoprene monomers and at least about 30%
butadiene monomers, the percentages being based on the total number
of monomers that make up the midblock polymer. Similarly, other
A-B-A triblock copolymers which have a hydrogenated midblock
polymer that is made up of at least about 30% ethylene/propylene
monomers and at least about 30% ethylene/butylene monomers, the
percentages being based on the total number of monomers that make
up the midblock polymer, are materials with chemical and physical
characteristics similar to those of SEPTON 4055.
[0286] Mixtures of block copolymer elastomers are also useful as
the elastomer component of some of the formulations of the example
gel cushioning medium. In such mixtures, each type of block
copolymer contributes different properties to the material. For
example, high strength triblock copolymer elastomers are desired to
improve the tensile strength and durability of a material. However,
some high strength triblock copolymers are very difficult to
process with some plasticizers. Thus, in such a case, block
copolymer elastomers which improve the processability of the
materials are desirable.
[0287] In particular, the process of compounding SEPTON 4055 with
plasticizers may be improved via a lower melt viscosity by using a
small amount of more flowable elastomer such as SEPTON 8006, SEPTON
2005, SEPTON 2006, or SEPTON 4033, to name only a few, without
significantly changing the physical characteristics of the
material.
[0288] In a second example of the usefulness of block copolymer
elastomer mixtures in the example gel materials, many block
copolymers are not good compatibilizers. Other block copolymers
readily form compatible mixtures, but have other undesirable
properties. Thus, the use of small amount of elastomers which
improve the uniformity with which a material mixes are desired.
KRATONO G 1701, manufactured by Shell Chemical Company of Houston,
Tex., is one such elastomer that improves the uniformity with which
the components of the example gel material mix.
[0289] Many other elastomers, including but not limited to triblock
copolymers and diblock copolymers are also useful in the example
gel material. Applicant believes that elastomers having a
significantly higher molecular weight than the ultra-high molecular
weight elastomers useful in the example gel material increase the
softness thereof, but decrease the strength of the gel. Thus, high
to ultra high molecular weight elastomers, as defined above, are
desired for use in the example gel material due to the strength of
such elastomers when combined with a plasticizer.
[0290] Additives
Polarizable Plasticizer Bleed-Reducing Additives 65
[0291] Preferably, the gel materials used in the cushions do not
exhibit migration of plasticizers, even when placed against
materials which readily exhibit a high degree of capillary action,
such as paper, at room temperature.
[0292] A example plasticizer bleed-reducing additive that is useful
in the example gel cushioning material includes hydrocarbon chains
with readily polarizable groups thereon. Such polarizable groups
include, without limitation, halogenated hydrocarbon groups,
halogens, nitriles, and others. Applicant believes that the
polarizability of such groups on the hydrocarbon molecule of the
bleed-reducing additive have a tendency to form weak van der Waals
bonding with the long hydrocarbon chains of the rubber portion of
an elastomer and with the plasticizer molecules. Due to the great
length of typical rubber polymers, several of the bleed-reducers
will be attracted thereto, while fewer will be attracted to each
plasticizer molecule. The bleed-reducing additives are believed to
hold the plasticizer molecules and the elastomer molecules thereto,
facilitating attraction between the elastomeric block and the
plasticizer molecule. In other words, the example bleed-reducing
additives are believed to attract a plasticizer molecule at one
polarizable site, while attracting an elastomeric block at another
polarizable site, thus maintaining the association of the
plasticizer molecules with the elastomer molecules, which inhibits
exudation of the plasticizer molecules from the
elastomer-plasticizer compound. Thus, each of the plasticizer
molecules is preferably attracted to an elastomeric block by means
of a bleed-reducing additive.
[0293] The example bleed-reducing additives that are useful in the
example gel material have a plurality of polarizable groups
thereon, which facilitate bonding an additive molecule to a
plurality of elastomer molecules and/or plasticizer molecules. It
is believed that an additive molecule with more polarizable sites
thereon will bond to more plasticizer molecules. Preferably, the
additive molecules remain in a liquid or a solid state during
processing of the gel material.
[0294] The most example bleed-reducing additives for use in the
example gel material are halogenated hydrocarbon additives such as
those sold under the trade name DYNAMAR.TM. PPA 791, DYNAMAR.TM.
PPA-790, DYNAMAR.TM. FX-9613, and FLUORAD.RTM.) FC 10
Fluorochemical Alcohol, each by 3M Company of St. Paul, Minn. Other
additives are also useful to reduce plasticizer exudation from the
example gel material. Such additives include, without limitation,
other halogenated hydrocarbons sold under the trade name
FLUORAD.RTM., including without limitation FC-129, FC-135, FC-430,
FC-722, FC-724, FC-740, FX-8, FX-13, FX-14 and FX-189; halogentated
hydrocarbons such as those sold under the trade name ZONYL.RTM.,
including without limitation FSN 100, FSO 100, PFBE, 8857A, TM,
BA-L, BA-N, TBC and FTS, each of which are manufactured by du Pont
of Wilmington, Del.; halogenated hydrocarbons, sold under the trade
name EMCOL by Witco Corp of Houston, Tex., including without
limitation 4500 and DOSS;
[0295] other halogenated hydrocarbons sold by 3M under the trade
name DYNAMA.RTM; chlorinated polyethylene elastomer (CPE),
distributed by Harwick, Inc. of Akron, Ohio; chlorinated paraffin
wax, distributed by Harwick, Inc.; and others.
Detackifiers
[0296] The example material may include a detackifier. Tack is not
a desirable feature in many potential uses for the cushions.
However, some of the elastomeric copolymers and plasticizers useful
in the example cushioning media for the cushioning elements may
impart tack to the media.
[0297] Soaps, detergents and other surfactants have detackifying
abilities and are useful in the example gel material.
"Surfactants," as defined herein, refers to soluble surface active
agents which contain groups that have opposite polarity and
solubilizing tendencies. Surfactants form a monolayer at interfaces
between hydrophobic and hydrophilic phases; when not located at a
phase interface, surfactants form micelles. Surfactants have
detergency, foaming, wetting, emulsifying and dispersing
properties. Sharp, D. W. A., DICTIONARY of CHEMISTRY, 381-82
(Penguin, 1990). For example, coco diethanolamide, a common
ingredient in shampoos, is useful in the example gel material as a
detackifying agent. Coco diethanolamide resists evaporation, is
stable, relatively non-toxic, non-flammable and does not support
microbial growth. Many different soap or detergent compositions
could be used in the material as well.
[0298] Other known detackifiers include glycerin, epoxidized
soybean oil, dimethicone, tributyl phosphate, block copolymer
polyether, diethylene glycol mono oleate, tetraethyleneglycol
dimethyl ether, and silicone, to name only a few. Glycerine is
available from a wide variety of sources. Witco Corp. of Greenwich,
Conn. sells epoxidized soybean oil as DRAPEX 6.8. Dimethicone is
available from a variety of vendors, including GE Specialty
Chemicals of Parkersburg, W. Va. under the trade name GE SF 96-350.
C.P. Hall Co. of Chicago, Ill. markets block copolymer polyether as
PLURONIC L-61. C.P. Hall Co. also manufactures and markets
diethylene glycol mono oleate under the name Diglycol Oleate Hallco
CPH-1-SE. Other emulsifiers and dispersants are also useful in the
example gel material. Tetraethyleneglycol dimethyl ether is
available under the trade name TETRAGLYME from Ferro Corporation of
Zachary, La. Applicant believes that TETRAGLYME also reduces
plasticizer exudation from the example gel material.
[0299] Antioxidants
[0300] The example gel material also includes additives such as an
antioxidant. Antioxidants such as those sold under the trade names
IRGANOX.RTM. 1010 and IRGAFOS.RTM. 168 by Ciba-Geigy Corp. of
Tarrytown, N.Y. are useful by themselves or in combination with
other antioxidants in the example materials.
[0301] Antioxidants protect the example gel materials against
thermal degradation during processing, which requires or generates
heat. In addition, antioxidants provide long term protection from
free radicals. A example antioxidant inhibits thermo-oxidative
degradation of the compound or material to which it is added,
providing long term resistance to polymer degradation. Preferably,
an antioxidant added to the example gel cushioning medium is useful
in food packaging applications, subject to the provisions of 21
C.F.R. .sctn. 178.2010 and other laws.
[0302] Heat, light (in the form of high energy radiation),
mechanical stress, catalyst residues, and reaction of a material
with impurities all cause oxidation of the material. In the process
of oxidation, highly reactive molecules known as free radicals are
formed and react in the presence of oxygen to form peroxy free
radicals, which further react with organic material (hydro-carbon
molecules) to form hydroperoxides.
[0303] The two major classes of antioxidants are the primary
antioxidants and the secondary antioxidants. Peroxy free radicals
are more likely to react with primary antioxidants than with most
other hydrocarbons. In the absence of a primary antioxidant, a
peroxy free radical would break a hydrocarbon chain. Thus, primary
antioxidants deactivate a peroxy free radical before it has a
chance to attack and oxidize an organic material.
[0304] Most primary antioxidants are known as sterically hindered
phenols. One example of sterically hindered phenol is the
C73H108,012 marketed by Ciba-Geigy as IRGANOX.RTM. 1010, which has
the chemical name
3,5-bis(1,1-dimethylethyl)-4-hydroxybenzenepropanoic acid,
2,2-bis[[3-[3,5-bis(dimethyletllyl)-4-hydroxyphenyl]-1-oxopropoxy]methyl]-
1,3-propanediyl ester. The FDA refers to IRGANOX.RTM. 1010 as
tetrakis[methylene(3,5-di-tert-butyl-4-hydroxyhydrocinnimate)]methane.
Other hindered phenols are also useful as primary antioxidants in
the example material.
[0305] Similarly, secondary antioxidants react more rapidly with
hydroperoxides than most other hydrocarbon molecules. Secondary
antioxidants have been referred to as hydroperoxide decomposers.
Thus, secondary antioxidants protect organic materials from
oxidative degradation by hydroperoxides.
[0306] Commonly used secondary antioxidants include the chemical
classes of phosphites/phosphonites and thioesters, many of which
are useful in the example gel material. The hydroperoxide
decomposer used by Applicant is a CQZH6,03P phosphite known as
Tris(2,4 di-tert-butylphenyl)phosphite and marketed by Ciba-Geigy
as IRGAFOS.RTM. 168.
[0307] It is known in the art that primary and secondary
antioxidants form synergistic combinations to ward off attacks from
both peroxy free radicals and hydroperoxides.
[0308] Other antioxidants, including but not limited to
multi-functional antioxidants, are also useful in the example
material. Multifunctional antioxidants have the reactivity of both
a primary and a secondary antioxidant. IRGANOX.RTM. 1520 D,
manufactured by Ciba-Geigy is one example of a multifunctional
antioxidant. Vitamin E antioxidants, such as that sold by CibaGeigy
as IRGANOX.RTM. E17, are also useful in the example cushioning
material for use in the cushions.
[0309] Preferably, the example gel material includes up to about
three weight percent antioxidant, based on the weight of the
elastomer component, when only one type of antioxidant is used. The
material may include as little as 0.1 weight percent of an
antioxidant, or no antioxidant at all. When a combination of
antioxidants is used, each may comprise up to about three weight
percent, based on the weight of the elastomer component. Additional
antioxidants may be added for severe processing conditions
involving excessive heat or long duration at a high
temperature.
[0310] Applicant believes that the use of excess antioxidants
reduces or eliminates tack on the exterior surface of the example
gel material. Excess antioxidants appear to migrate to the exterior
surface of the material following compounding of the material. Such
apparent migration occurs over substantial periods of time, from
hours to days or even longer.
Flame Retardants
[0311] Flame retardants may also be added to the example gel
materials. Flame retardants useful in the cushioning elements
include but are not limited to diatomaceous earth flame retardants
sold as GREAT LAKES DE 83R and GREAT LAKES DE 79 by Great Lakes
Filter, Division of Acme Mills Co. of Detroit, Mich. Most flame
retardants that are useful in elastomeric materials are also useful
in the example gel material. In particular, Applicant prefers the
use of food grade flame retardants which do not significantly
diminish the physical properties of the example gel material.
[0312] Chemical blowing agents, such as SAFOAM.RTM. FP-40,
manufactured by Reedy International Corporation of Keyport, N.J.
and others are useful for making a gel cushioning medium that is
self-extinguishing.
Colorants
[0313] Colorants may also be used in the example gel materials for
use in the cushions. Any colorant which is compatible with
elastomeric materials may be used in the materials. In particular,
Applicant prefers to use aluminum lake colorants such as those
manufactured by Warner Jenkinson Corp. of St. Louis, Mo.; pigments
manufactured by Day Glo Color Corp. of Cleveland, Ohio; Lamp Black,
such as that sold by Spectrum Chemical Manufacturing Corp. of
Gardena, Calif.; and Titanium Dioxide (white). By using these
colorants, the gel material takes on intense shades of colors,
including but not limited to pink, red, orange, yellow, green,
blue, violet, brown, flesh, white and black.
Paint
[0314] The example gel cushioning medium may also be painted.
Other Additives
[0315] Other additives may also be added to the example gel
material. Additives such as foaming facilitators, tack modifiers,
plasticizer bleed modifiers, flame retardants, melt viscosity
modifiers, melt temperature modifiers, tensile strength modifiers,
and shrinkage inhibitors are useful in specific formulations of the
example gel material.
[0316] Melt temperature modifiers useful in the example gel include
cross-linking agents, hydrocarbon resins, diblock copolymers of the
general configuration A-B and triblock copolymers of the general
configuration A-B-A wherein the end block A polymers include
functionalized styrene monomers, and others.
[0317] Tack modifiers which tend to reduce tack and which are
useful in the example gel include surfactants, dispersants,
emulsifiers, and others. Tack modifiers which tend to increase the
tack of the material and which are useful in the material include
hydrocarbon resins, polyisobutylene, butyl rubber and others.
[0318] Foam facilitators that are useful in the gel material
include polyisobutylene, butyl rubber, surfactants, emulsifiers,
dispersants and others.
[0319] Plasticizer bleed modifiers which tend to reduce plasticizer
exudation from the example material and which are useful therein
include hydrocarbon resins, elastomeric diblock copolymers,
polyisobutylene, butyl rubber, transpolyoctenylene rubber ("tor
rubber"), and others.
[0320] Flame retardants useful in the example gel include
halogenated flame retardants, non-halogenated flame retardants, and
volatile, non-oxygen gas forming chemicals and compounds.
[0321] Melt viscosity modifiers that tend to reduce the melt
viscosity of the pre-compounded component mixture of the example
cushioning medium include hydrocarbon resins, transpolyoctenylene
rubber, castor oil, linseed oil, non-ultra high molecular weight
thermoplastic rubbers, surfactants, dispersants, emulsifiers, and
others.
[0322] Melt viscosity modifiers that tend to increase the melt
viscosity of the pre-compounded component mixture of the example
gel material include hydrocarbon resins, butyl rubber,
polyisobutylene, additional triblock copolymers having the general
configuration A-B-A and a molecular weight greater than that of
each of the block copolymers in the elastomeric block copolymer
component of the material, particulate fillers, microspheres,
butadiene rubber, ethylene/propylene rubber, ethylene/butylene
rubber, and others.
[0323] Tensile strength modifiers which tend to increase the
tensile strength of the example gel material for use in the
cushions include mid block B-associating hydrocarbon resins,
non-end-block solvating hydrocarbon resins which associate with the
end blocks, particulate reinforcers, and others.
[0324] Shrinkage inhibitors, which tend to reduce shrinkage of the
gel material following compounding, that are useful in the material
include hydrocarbon resins, particulate fillers, microspheres,
transpolyoctenylene rubber, and others.
Microspheres
[0325] Microspheres may also be added to the example gel material.
The gel material may contain up to about 90% microspheres, by
volume. In one example microsphere-containing formulation of the
example gel material, microspheres make up at least about 30% of
the total volume of the material. A second example
microsphere-containing formulation of the example gel cushioning
medium includes at least about 50% microspheres, by volume.
[0326] Different types of microspheres contribute various
properties to the material. For example, hollow acrylic
microspheres, such as those marketed under the brand name
MICROPEARL, and generally in the 20 to 200 micron size range, by
Matsumoto Yushi-Seiyaku Co., Ltd. of Osaka, Japan, lower the
specific gravity of the material. In other formulations of the gel,
the microspheres may be unexpanded DU(091-80), which expand during
processing of the example gel cushioning medium, or pre-expanded DE
(091-80) acrylic microspheres from Expancel Inc. of Duluth, Ga.
[0327] In formulations of the example material which include hollow
acrylic microspheres, the microspheres preferably have
substantially instantaneous rebound when subjected to a compression
force which compresses the microspheres to a thickness of up to
about 50% of their original diameter or less.
[0328] Hollow microspheres also decrease the specific gravity of
the gel material by creating gas pockets therein. In many
cushioning applications, very low specific gravities are example.
The specific gravity of the example gel cushioning medium may range
from about 0.06 to about 1.30, depending in part upon the amount
and specific gravity of fillers and additives, including
microspheres and foaming agents. In many cushioning applications, a
gel material having a specific gravity of less than about 0.50 is
example. When a gel material example for use in cushions includes
the example microspheres, the microspheres must be dispersed, on
average, at a distance of about one-and-a half (1.5) times the
average microsphere diameter or a lesser distance from one another
in order to achieve a specific gravity of less than about 0.50. A
specific gravity of less than about 0.30 is example for use in some
cushions. Other formulations of the example gel material have
specific gravities of less than about 0.65, less than about 0.45,
and less than about 0.25.
[0329] MICROPEARL and EXPANCEL acrylic microspheres are example
because of their highly flexible nature, as explained above, which
tend to not restrict deformation of the thermoplastic elastomer.
Glass, ceramic, and other types of microspheres may also be used in
the thermoplastic gel material, but are less example.
Plasticizer Component
[0330] As explained above, plasticizers allow the midblocks of a
network of triblock copolymer molecules to move past one, another.
Thus, Applicant believes that plasticizers, when trapped within the
three dimensional web of triblock copolymer molecules, facilitate
the disentanglement and elongation of the elastomeric midblocks as
a load is placed on the network. Similarly, Applicant believes that
plasticizers facilitate recontraction of the elastomeric midblocks
following release of the load. The plasticizer component of the
example gel cushioning medium may include oil, resin, a mixture of
oils, a mixture of resins, other lubricating materials, or any
combination of the foregoing.
Oils
[0331] The plasticizer component of the example gel material may
include a commercially available oil or mixture of oils. The
plasticizer component may include other plasticizing agents, such
as liquid oligomers and others, as well. Both naturally derived and
synthetic oils are useful in the example gel material. Preferably,
the oils have a viscosity of about 70 SUS to about 500 SUS at about
100.degree. F. Most example for use in the gel material are
paraffinic white mineral oils having a viscosity in the range of
about 90 SUS to about 200 SUS at about 100.degree. F.
[0332] One embodiment of a plasticizer component of the example gel
includes paraffinic white mineral oils, such as those having the
brand name DUOPRIME, by Lyondell Lubricants of Houston, Tex., and
the oils sold under the brand name TUFFLO by Witco Corporation of
Petrolia, Pa. For example, the plasticizer component of the example
gel may include paraffinic white mineral oil such as that sold
under the trade name LP-150 by Witco.
[0333] Paraffinic white mineral oils having an average viscosity of
about 90 SUS, such as DUOPRIME 90, are example for use in other
embodiments of the plasticizer component of the example gel
cushioning medium. Applicant has found that DUOPRIME 90 and oils
with similar physical properties can be used to impart the greatest
strength to the example gel 9 material.
[0334] Other oils are also useful as plasticizers in compounding
the gel material. Examples of representative commercially available
oils include processing oils such as paraffinic and naphthenic
petroleum oils, highly refined aromatic-free or low aromaticity
paraffinic and naphthenic food and technical grade white petroleum
mineral oils, and synthetic liquid oligomers of polybutene,
polypropene, polyterpene, etc., and others. The synthetic series
process oils are oligomers which are permanently fluid liquid
non-olefins, isoparaffrns or paraffrns. Many such oils are known
and commercially available. Examples of representative commercially
available oils include Amoco.RTM. polybutenes, hydrogenated
polybutenes and polybutenes with epoxide functionality at one end
of the polybutene polymer. Examples of such Amoco polybutenes
include: L-14 (320 Mn), L-50 (420 Mn), L-100 (460 Mn), H-15 (560
Mn), H-25 (610 Mn), H-35 (660 Mn), H-50 (750 Mn),13-100 (920 Mn),
H-300 (1290 Mn, L-14E (27-37 cst @ 100.degree. F. Viscosity),
L-300E (635-6'90 cst @ 210.degree. F. Viscosity), Actipol E6 (365
Mn), E16 (973 Mn), E23 (1433 Mn) and the like. Examples of various
commercially available oils include: Bayol, Bernol, American,
Blandol, Drakeol, Ervol, Gloria, Kaydol, Litetek, Marcol, Parol,
Peneteck, Pnmol, Protol, Sontex, and the like.
Resins
[0335] Resins useful in the plasticizer component of the example
gel material include, but are not limited to, hydrocarbon-derived
and rosin-derived resins having a ring and ball softening point of
up to about 150.degree. C., more preferably from about 0.degree. C.
to about 25.degree. C., and a weight average molecular weight of at
least about 300.
[0336] For use in many of the cushions, the use of resins or resin
mixtures which are highly viscous flowable liquids at room
temperature (about 23.degree. C.) may be employed. Plasticizers
which are fluid at room temperature impart softness to the gel
material. Although room temperature flowable resins are example,
resins which are not flowable liquids at room temperature are also
useful in the material.
[0337] The resins most example for use in the example gel material
have a ring and ball softening point of about 18.degree. C.; melt
viscosities of about 10 poises (ps) at about 61.degree. C., about
100 ps at about 42.degree. C. and about 1,000 ps at about
32.degree. C.; an onset Tg of about -20.degree. C.; a MMAP value of
68.degree. C.; a DACP value oi' 15.degree. C.; an OMSCP value of
less than -40.degree. C.; a Mn of about 385; a Mw, of about 421;
and a MZ of about 463. One such resin is marketed as REGALREZ.RTM.
1018 by Hercules Incorporated of Wilmington, Del. Variations of
REGALREZ.RTM. 1018 which are useful in the example cushioning
material have viscosities including, but not limited to, 1025
stokes, 1018 stokes, 745 stokes, 114 stokes, and others.
[0338] Room temperature flowable resins that are derived from
poly-.beta.-pinene and have softening points similar to that of
REGALREZ.RTM. 1018 are also useful in the plasticizer component of
the example cushioning medium. One such resin, sold as
PICCOLYTE.RTM. S25 by Hercules Incorporated, has a softening point
of about 25.degree. C.; melt viscosities of about 10 ps at about
80.degree. C., about 100 ps at about 56.degree. C. and about 1,000
ps at about 41.degree. C.; a MMAP value of about 88.degree. C.; a
DACP value of about 45.degree. C.; an OMSCP value of less than
about -50.degree. C.; a MZ of about 4,800; a Mw of about 1,950; and
a Mn of about 650. Other PICCOLYTE.RTM.) resins may also be used in
the example gel material.
[0339] Another room temperature flowable resin which is useful in
the plasticizer component of the example material is marketed as
ADTAC.RTM.) LV by Hercules Incorporated. That resin has a ring and
ball softening point of about 5.degree. C.; melt viscosities of
about 10 ps at about 62.degree. C., about 100 ps at about
36.degree. C. and about 1,000 ps at about 20.degree. C.; a MMAP
value of about 93.degree. C.; a DACP value of about 44.degree. C.;
an OMSCP value of less than about -40.degree. C.; a MZ of about
2,600; a Mw of about 1,380; and a Mn of about 800.
[0340] Resins such as the: liquid aliphatic C-5 petroleum
hydrocarbon resin sold as WINGTACK.RTM. 10 by the Goodyear Tire
& Rubber Company of Akron, Ohio and other WINGTACK.RTM. resins
are: also useful in the gel material. WINGTACK.RTM. 10 has a ring
and ball softening point of about 1.0.degree. C.; a Brookfield
Viscosity of about 30,000 cps at about 25.degree. C.:; melt
viscosities of about 10 ps at about 53.degree. C. and about 100 ps
at about 34.degree. C.; an onset Tg of about -37.7.degree. C.; a Mn
of about 660; a Mw of about 800; a 1:1 polyethylene-to-resin ratio
cloud point of about 89.degree. C.; a 1:1 microcrystalline
wax-to-resin ratio cloud point of about 77.degree. C.; and a 1:1 79
paraffin wax-to-resin ratio cloud point of about 64.degree. C.
[0341] Resins that are not readily flowable at room temperature
(i.e., are solid, semi-solid, or have an extremely high viscosity)
or that are solid at room temperature are also useful in the
example gel material. One such solid resin is an aliphatic C-5
petroleum hydrocarbon resin having a ring and ball softening point
of about 98.degree. C.; melt viscosities of about 100 ps at about
156.degree. C. and about 1000 ps at about 109.degree. C.; an onset
Tg of about 46.1.degree. C.; a Mn of about 1,130; a MW of about
1,800; a 1:1 polyethylene-to-resin ratio cloud point of about
90.degree. C.; a 1:1 microcrystalline wax-to-resin ratio cloud
point of about 77.degree. C.; and a 1:1 paraffin wax-to-resin ratio
cloud point of about ,64.degree. C. Such a resin is available as
WINGTACK.RTM. 95 and is manufactured by Goodyear Chemical Co.
[0342] Polyisobutylene polymers are an example of resins which are
not readily flowable at room temperature and that are useful in the
example gel material. One such resin, sold as VISTANEX.RTM. LM-MS
by Exxon Chemical Company of Houston, Tex., has a Tg of -60.degree.
C., a Brookfield Viscosity of about 250 cps to about 350 cps at
about 3500F., a Flory molecular weight in the range of about 42,600
to about 46,100, and a Staudinger molecular weight in the range of
about 10,400 to about 10,900. The Flory and Staudinger methods for
determining molecular weight are based on the intrinsic viscosity
of a material dissolved in diisobutylene at 18 20.degree. C.
[0343] Glycerol esters of polymerized rosin are also useful as
plasticizers in the example gel material. One such ester,
manufactured and sold by Hercules Incorporated as HERCULES.RTM.
Ester Gum I OD Synthetic Resin, has a softening point of about
116.degree. C.
[0344] Many other resins are also suitable for use in the gel
material. In general, plasticizing resins are example which are
compatible with the B block of the elastomer used in the material,
and non-compatible with the A blocks.
[0345] In some embodiments of the cushion, tacky materials may be
desirable. In such embodiments, the plasticizer component of the
gel material may include about 20 weight percent or more, about 40
weight percent or more, about 60 weight percent or more, or up to
about 100 weight percent, based upon the weight of the plasticizer
component, of a tackifier or tackifier mixture.
Plasticizer Mixtures
[0346] The use of plasticizer mixtures in the plasticizer component
of the example gel material is useful for tailoring the physical
characteristics of the example gel material. For example,
characteristics such as durometer, tack, tensile strength,
elongation, melt flow and others may be modified by combining
various plasticizers.
[0347] For example, a plasticizer mixture which includes at least
about 37.5 weight percent of a paraffinic white mineral oil having
physical characteristics similar to those of LP-150 (a viscosity of
about 150 SUS at about 100.degree. F., a viscosity of about 30
centistokes (cSt) at about 40.degree. C., and maximum pour point of
about -35.degree. F.) and up to about 62.5 weight percent of a
resin having physical characteristics similar to those of REGALREZO
1018 (such as a softening point of about 20.degree. C.; an onset T9
of about -20.degree. C.; a MMAP value of about 70.degree. C.; a
DACP value of about 15.degree. C.; an OMSCP value of less than
about -40.degree. C.; and M, of about 400), all weight percentages
being based upon the total weight of the plasticizer mixture, could
be used in a gel cushioning medium. When compared to a material
plasticized with the same amount of an oil such as LP-150, the
material which includes the plasticizer mixture has decreased oil
bleed and increased tack.
[0348] Applicant believes that, when resin is included with oil in
a plasticizer mixture of the example gel for use in cushions, the
material exhibits reduced oil bleed. For example, a formulation of
the material which includes a plasticizing component which has
about three parts plasticizing oil (such as LP-150), and about five
parts plasticizing resin (such as REGALREZ8 1018) exhibits
infinitesimal oil bleed at room temperature, if any, even when
placed against materials with high capillary action, such as paper.
Prior art thermoplastic elastomers bleed noticeably under these
circumstances.
[0349] The plasticizer:block copolymer elastomer ratio, by total
combined weight of the plasticizer component and the block
copolymer elastomer component, of the example gel cushioning
material for use in the cushions ranges from as low as about 1:1 or
less to higher than about 25:1. In applications where plasticizer
bleed is acceptable, the ratio may as high as about 100:1 or more.
Especially example are plasticizer:block copolymer ratios in the
range of about 2.5:1 to about 8:1. A example ratio, such as 5:1
provides the desired amounts of rigidity, elasticity and strength
for many typical applications. Another example plasticizer to block
copolymer elastomer ratio of the example gel material is 2.5:1,
which has an unexpectedly high amount of strength and
elongation.
[0350] Compounding Methods
[0351] As used herein, the term "liquification" refers to the
placement of the block copolymer elastomer and plasticizer
components of the example gel cushioning medium in a liquid state,
such as a molten state or a dissolved state.
[0352] Melt Blending
[0353] A example method for manufacturing the example gel material
includes mixing the plasticizer, block copolymer elastomer and any
additives and/or fillers (e.g., microspheres), heating the mixture
to melting while agitating the mixture, and cooling the compound.
This process is referred to as "melt blending."
[0354] Excessive heat is known to cause the degradation of the
elastomeric B portion of A-B-A and A-B block copolymers which are
the example elastomer component of the example gel material for use
in the cushions. Similarly, maintaining block copolymers at
increased temperatures over prolonged periods of time often results
in the degradation of the elastomeric B portion of A-B-A and A-B
block copolymers. As the B molecules of an A-B-A triblock copolymer
break, the triblock is separated into two diblock copolymers having
the general configuration A-B. While it is believed by some in the
art that the presence of A-B diblock copolymers in oil-containing
plasticizer-extended A-B-A triblock copolymers reduces plasticizer
bleed-out, high amounts of A-B copolymers significantly reduce the
strength of the example gel material. Thus, Applicant believes that
it is important to minimize the compounding temperatures and the
amount of time to which the material is exposed to heat.
[0355] The plasticizers, any additives and/or fillers, and the
A-B-A copolymers are premixed. Preferably, if possible, hydrophobic
additives are dissolved into the plasticizer prior to adding the
plasticizer component to the elastomer component. If possible,
hydrophilic additives and particulate additives are preferably
emulsified or mixed into the plasticizer of a example gel material
prior to adding the elastomer components. The mixture is then
quickly heated to melting. Preferably, the temperature of the
mixture does not exceed the volatilization temperature of any
component. For some of the example gel materials, Applicant prefers
temperatures in the range of about 270.degree. F. to about
290.degree. F. For other gel materials, Applicant prefers
temperatures in the range of about 360.degree. F. to about
400.degree. F. A melting time of about ten minutes or less is
example. A melting time of about five minutes or less is more
example. Even more example are melting times of about ninety
seconds or less. Stirring, agitation, or, most preferably, high
shearing forces are example to create a homogeneous mixture. The
mixture is then cast, extruded, injection molded, etc.
[0356] Next, the mixture is cooled. When injection molding
equipment and cast molds are used, the mixture may be cooled by
running coolant through the mold, by the thermal mass of the mold
itself, by room temperature, by a combination of the above methods,
or other methods. Extruded mixtures are cooled by air or by passing
the extruded mixture through coolant. Cooling times of about five
minutes or less are example. A cooling time of less than one minute
is most example.
[0357] Use of high shear facilitates short heating times. "High
shear", for purposes of this disclosure, is defined in terms of the
length over diameter (L/D) ratio of a properly designed injection
molding single screw or extruder single screw. L/D ratios of about
20:1 and higher create high shear. Twin screws, Banbury mixers and
the like also create high shear. High shearing with heat mixes
compounds at lower temperatures and faster rates than the use of
heat alone or heat with relatively low-shear mixing. Thus, high
shear forces expedite compounding of the mixture over a relatively
short period of time by more readily forcing the molecules into
close association with the 13 component of the A-B-A copolymer. Use
of high shear also facilitates the decrease of equipment
temperatures. Melt blending techniques which employ little or no
shear require an external heat source. Thus, in order to avoid heat
loss, the periphery of many types of melt blending equipment must
be heated to a temperature higher than the melt temperature in
order to transfer heat and melt a component mixture. In comparison,
high shearing equipment can generate high material temperatures
directly from the shear forces, substantially reducing or
eliminating the need for external heating.
[0358] The use of equipment that produces high shear, such as twin
screw compounding extrusion machinery, to melt blend the example
gel cushioning medium can be employed. Twin screw extruders such as
the ZE25 TIEBAR AIR COOLED TWIN SCREW EXTRUDER, with a 35:1 L/D
ratio, manufactured by Berstorff Corporation of Charlotte, N.C.,
are useful for compounding the example gel material. Twin screw
compounding extrusion machinery is desired for compounding the
example gel material since it generates a very high level of shear
and because compounding and molding, casting, extrusion, or foaming
are performed in one continuous process. Alternatively, the example
thermoplastic elastomeric may be compounded first, then later
formed into a finished product by injection molding, extrusion, or
some other 20 method.
[0359] It was mentioned above that microspheres may be added to the
gel material to reduce its specific gravity and to increase its
stiffness or durometer. Applicant has unexpectedly discovered that
acrylic microspheres remain intact when subjected to the heat and
shear of injection molding machines and extruders if the time at
high temperature is kept to about five minutes or less.
[0360] Other equipment, such as batch mixers are also useful for
melt blending the example gel materials for use in the
cushions.
[0361] Solvent Blending
[0362] A second example method for making the example elastomeric
compounds comprises dissolving the elastomeric component in a
solvent, adding the plasticizer component and any additives and/or
fillers, and removing the solvent from the mixture.
[0363] Aromatic hydrocarbon solvents such as toluene may be used
for mixing the example gel compounds. Sufficient solvent is added
to the elastomer component to dissolve the network of block
copolymer molecules. Preferably, the amount of solvent is limited
to an amount sufficient for dissolving the network: of block
copolymer molecules. The elastomers then dissolve in the solvent.
Mixing is example since it speeds up the solvation process.
Similarly, slightly elevating the mixture temperature is example
since it speeds up the solvation process. Next, plasticizer, any
additives and any fillers are mixed into the solvated elastomer. If
possible, hydrophobic additives are preferably dissolved in the
plasticizer prior to adding the plasticizer to the principle
polymer, the block copolymer elastomer and the solvent. Preferably,
if possible, hydrophilic additives and particulate additives are
emulsified or mixed into the plasticizer prior to adding the
elastomer components and solvent. The mixture is then cast into a
desired shape (accounting for later shrinkage due to solvent loss)
and the solvent is evaporated from the mixture.
[0364] Other methods of compounding the example materials,
including but not limited to other processes for compounding,
modifying and extending elastomeric materials, are also useful for
compounding the example gel cushioning medium.
[0365] Foaming
[0366] The example gel material may be foamed. "Foaming", as
defined herein, refers to processes which form gas bubbles or gas
pockets in the material. A example foamed gel material that is
useful in the cushions hereof includes gas bubbles dispersed
throughout the material. Both open cell and closed cell foaming are
useful in the example gel material. Foaming decreases the specific
gravity of the example material. In many cushioning applications,
very low specific gravities are example. The specific gravity of
the gel material may range, after foaming, from about 0.06 to about
1.30.
[0367] A example foamed formulation of the gel material includes at
least about 10% gas bubbles or gas pockets, by volume of the
material. More preferably, when the material is foamed, gas bubbles
or gas pockets make up at least about 20% of the volume of the
material. Other foamed formulations of the example gel material
contain at least about 40% gas bubbles or gas pockets, by volume,
and at least about 70% gas bubbles or pockets, by volume. Various
methods for foaming the example gel material include, but are not
limited to, whipping or injecting air bubbles into the material
while it is in a molten state, adding compressed gas or air to the
material while it is in the molten state and under pressure, adding
water to the material while it is in the molten state, use of
sodium bicarbonate, and use of chemical blowing agents such as
those marketed under the brand name SAFOAM.RTM. by Reedy
International Corporation of Keyport, N.J. and those manufactured
by Boehringer Ingelheim of Ingelheim, Germany under the trade name
HYDROCEROL.RTM..
[0368] When blowing agents such as sodium bicarbonate and chemical
blowing agents are used in the example gel material, the material
temperature is preferably adjusted just prior to addition of the
blowing agent so that the material temperature is just above the
blowing temperature of the blowing agent. Following; addition of
the blowing agent to the material, the material is allowed to cool
so that it will retain the gas bubbles or gas pockets formed by the
release of gas from the blowing agent. Preferably, the material is
quickly cooled to a temperature below its Tg. The material will
retain more gas bubbles and the gas bubbles will be more
consistently dispersed throughout the material the quicker the
material temperature cools to a temperature below the Tg.
[0369] When a example gel material is injection molded in
accordance with one example compounding; method of the gel
material, foaming is example just after the material has been
injected into a mold. Thus, as the material passes through the
injection molding machine nozzle, its temperature is preferably
just higher than the blowing temperature of the blowing agent.
Preferably, the material is then cooled to a temperature below its
Tg.
[0370] Addition of poly isobutylene resin improves the ability of
the example gel material to foam and retain cells during; the
foaming; process. One such resin, known as VISTANEX.RTM. LM MS, is
manufactured by Exxon Chemical Company. Similarly, surfactants,
dispersants and emulsifiers such as Laureth-23, available from
Lonza of Fair Lawn, N.J. under the trade name ETHOSPERSE LA-23, and
others may be used to facilitate foaming of the gel material. In
formulations which include oil, certain foaming oils such as
Hydraulic and Transmission Oil, such as that made by Spectrum Corp.
of Selmer, Tenn., may also be used in the material to facilitate
foaming of the materials.
[0371] Additives which modify the gas permeability of the example
gel material are example when the material is foamed. One such
material, manufactured by Rohm & Haas Company of Philadelphia,
Pa. and marketed under the trade name PARALOID.RTM. K 400, modifies
the gas permeability of the example gel material, facilitating the
material's ability to hold gas bubbles.
[0372] When foaming is desired, additives which increase the melt
viscosity or melt body of the material are also useful. One such
additive, PARALOID.RTM. K 400, is believed to increase the melt
viscosity of the material, making it more difficult for gas bubbles
to escape from the material as it cools. Another additive,
ACRYLOID.RTM. F-10, manufactured by Rohm & Haas, is also
believed to improve the ability of the material to entrap
bubbles.
[0373] Another additive, ethylene vinyl acetate (EVA) crosslinks
with itself and/or other molecules to increase the internal
structure of the material, while reducing the material's melt
viscosity. Thus, EVA is also believed to improve the gas bubble
retention of the material. EVA is available from a variety of
sources. High viscosity plasticizers, including without limitation
DUOPRIME 500, are also believed to facilitate gas bubble
retention.
[0374] Additives which act as nucleating agents are also useful for
foaming the example gel material. Such additives are helpful in
initiating the formation of gas bubbles. Applicant believes that
antioxidants, including but not limited to IRGANOX.RTM. 1010 and
IRGATOS.RTM. 168, act as nucleating agents during foaming of the
material. Blowing agents such as those sold under the trade name
SAFOAM.RTM. by Reedy International are also believed to have a
secondary function as nucleating agents. Examples of other
nucleating agents include talc, carbon black, aluminum stearate,
hydrated alumina, titanium dioxide, aluminum lake colorants, and
others.
[0375] Referring now to FIGS. 40a and 40b, a example embodiment of
a method for foaming the example gel cushioning material is shown.
FIG. 40a illustrates the example embodiment of the foaming method
using an extruder 4001. FIG. 10b shows the example embodiment of
the foaming method in an injection molding machine 4001'.
Preferably, the gel cushioning medium includes a blowing agent such
as SAFOAM.RTM. FP-40, which is added to the non-liquid components
of the cushioning medium prior to processing. About half of the
plasticizer component is then added to the non-liquid components,
which are then fed into extruder 4001 or injection molding machine
4001'. The remaining plasticizer is added to the mixture at 4003,
4003' as the mixture moves along the barrel 4004, 4004', which
houses the screw or screws. Pressurized carbon dioxide (CO2), which
is contained in a CO2 source 4008, 4008' such as a pressurized
cannister, is then injected into the barrel. The C02 is injected
into the mixture near the end of the barrel 4004, 4004', after a
seal 4006, 4006' and just before the nozzle 4007, 4007'.
Preferably, a pumping mechanism 4009, 4009' such as a stepping
pump, which are widely used in the industry, is used to increase
the pressure in barrel 4004, 4004'. The material is then discharged
through nozzle 4007, 4007'.
[0376] Referring to FIG. 40a, when an extruder 4001 is used to
compound and foam the example gel cushioning medium, a gear pump
4010, which is preferably positioned at the end of nozzle 4007,
controls the amount of pressure in barrel 4004 and inhibits a drop
in pressure at the nozzle. As the material is discharged from pump
4010 at 4011, the C02 expands, which introduces gas bubbles into
the material and foams the material.
[0377] With reference to FIG. 40b, when an injection molding
machine 4001' is used to compound and foam the example gel
material, an accumulator positioned just before nozzle 4007'
increases the material pressure. Following discharge from nozzle
4007', the material passes through a heat exchanger 4012 and into
the cavity (not shown) of a mold 4013. Preferably, the CO2 begins
to expand and form gas bubbles in the material as the material
fills the mold cavity.
[0378] Preferably, the CO2, and the material are maintained at a
pressure of at least about 700 psi just prior to entering the ;gear
pump at the extrusion end of the barrel. More preferably, the
material and CO2 reach a pressure of at least about 900 psi. Most
preferably. the CO2, and material are subjected to a pressure of at
least about 1,700 psi.
[0379] At pressures of about 1,700 psi and greater, CO2 acts as a
supercritical fluid. At such high pressure, the liquid CO2 solvates
the block copolymer and principle polymer, which decreases the Tg
of the mixture. Thus, as pressure is released upon extrusion of the
mixture from the nozzle, the CO2 immediately becomes a gas and the
mixture immediately crosses its Tg. In other words, as gas bubbles
are forming in the material, the material begins to solidify. Thus,
the number of gas bubbles retained in the material is increased.
CO2 bubbles are believed to form around the SAFOAMO, which is
believed to act as a nucleating agent.
[0380] The expansion rate of the CO2 bubbles and the solidification
rate of the mixture are varied, depending upon the particular
formulation of the material. Various other factors also affect how
a material will foam, including the rate at which material is fed
into the barrel (the "feed rate"), the length of time the material
is in the barrel (the "residence time"), the speed at which the
screw or screws rotate (the "screw rpm"), the relative direction
each screw rotates and others.
[0381] In addition, properties of the material affect the foaming
process. The amount of plasticizer affects a material's ability to
foam. For example, when the plasticizer is an oil, materials which
include increased amounts of plasticizer do not foam as readily as
similar materials with less plasticizing oil. Applicant believes
that as the amount of plasticizing oil in a material increases, gas
bubbles tend to more readily escape from the material.
[0382] Lattice Structures
[0383] Lattice structures may be made using the example gel
material, which is incorporated into the cushion configurations.
Such lattice structures include multiple overlaid streams of the
gel material in a lattice-like arrangement. Preferably, the streams
of material have a thickness of less than about one-tenth of an
inch.
[0384] Formation of the gel material into lattice structures
decreases the specific gravity of the material due to the free
space created within the lattice structure. Preferably, lattice
structures reduce the specific gravity of the material by at least
about 50%.
[0385] One method of foaming lattice structures includes heating
the material to a molten state and spraying streams of the material
to form a desired lattice structure. Preferably, a hot melt
adhesive spray gun, such as the FP-200 Gun System manufactured by
Nordson Corporation of Amherst, Ohio, is used to, spray streams of
the example gel cushioning material to form a lattice
structure.
[0386] Premixing of Microspheres
[0387] In formulations of the example material for use in the
cushioning elements hereof which include microspheres, premixing
the microspheres with the plasticizer prior to adding the
plasticizer to the elastomeric block copolymer and the polyolefin
may result in a more uniform mixture (i.e., a better final product)
and makes the microsphere-containing gel material easier to
process. For example, the materials may be premixed by hand.
[0388] Pre-Manufacture of Pellets
[0389] In some embodiments, it will be example to prepare
pelletized gelatinous elastomer material for later use in
manufacturing cushioning devices or other devices. The pelletized
gelatinous elastomer could be of any formulation described herein
or otherwise, and could contain any desired additives. The pellets
could be produced by first compounding the material and forming it
into pellets for later use in an appropriate manufacturing
process.
Representative Elastomeric Gel Physical Properties and
Formulations
[0390] When the example A-B-A triblock copolymer, plasticizer and
additives are mixed, the resultant material is very strong, yet
very elastic and easily stretched, having a Young's elasticity
modulus of only up to about 1.times.106 dyne/cm2. The example
elastomeric gel material for use in the cushioning elements hereof
also has low tack and little or no oil bleed, both of which are
believed to be related to the molecular weight of the uniquely
example elastomers as well as the molecular structure of the
elastomer and its interaction with the plasticizing component.
Finally, the example elastomeric gel cushioning medium is capable
of elongation up to about 2400% and more.
EXAMPLES
[0391] Examples 1 through 14 include various mixtures of SEPTON
4055 (available from Kuraray) ultra high molecular weight
polystyrene-hydrogenated poly(isoprene+butadiene) polystyrene
triblock copolymer extended in a plasticizing oil. In addition, the
materials of Examples 1 through 14 include very minor amounts of
IRGANOX.RTM. 1010 (about 0.03%), IRGAFOSV 168 (about 0.03%), and
colorant (about 0.04%).
[0392] The material of each of Examples 1 through 14 was compounded
in an ISF 120VL injection molding machine, manufactured by Toshiba
Machine Co. of Tokyo, Japan, with a 20:1 (L/D) high mixing single
screw manufactured by Atlantic Feed Screw, Inc. of Cayce, S.C. The
temperature in the injection molding machine was increased stepwise
from the point of insertion to the injection nozzle. At the point
of insertion, the temperature was about 270.degree. F. Temperatures
along the screw were about 275.degree. F. and about 280.degree. F.,
with the temperature increasing as the material approached the
injection nozzle. The temperature at the injection nozzle was about
290.degree. F. This gradual increase in temperature builds up
pressure during feeding of the material through the injection
molding machine, providing a more homogeneous mixture of the
components of the material.
[0393] Each of the formulations of Examples 1 through 11 were then
injected into an aluminum plaque mold and allowed to cure at room
temperature for about 24 hours to about 48 hours. Thereafter,
various tests were performed on the materials, including percent
elongation, tensile strength at break, and percent oil bleed.
[0394] Percent elongation and tensile strength testing were
performed in accordance with American Society for Testing and
Materials (ASTM) Standard Test Method D412, using a Model
QC-II-30XS-B Electronic Tensile Tester manufactured by Thwing
Albert Instrument Co. of Philadelphia, Pa. Each of samples were
O-shaped rings with an outer diameter of about 0.500 inch, an inner
diameter of about 0.375 inch, a gauge diameter of about 0.438 inch,
and a mean circumference of about 1.374 inches. Five samples of
each material were tested for elongation and tensile strength.
[0395] Percent oil bleed was measured by obtaining the combined
weight of three disk-shaped samples of the material, each sample
having diameter of about 3 cm and a thickness of about 6.5 nun. Two
pieces of 12.5 cm diameter qualitative filter paper having a medium
filter speed and an ash content of about 0.15%, such as that sold
under the trade name DOUBLE RINGS 102, and manufactured by Xinhua
Paper Mill, were then weighed individually.
[0396] The three sample disks were then placed on one of the pieces
of filter paper (which has high capillary action), and the other
piece of filter paper was placed on top of the samples. The
material and paper were then placed in a plastic bag and
pressure-sandwiched between two flat steel plates, each weighing
within about 0.5% of about 2285 g. Next, the material samples,
paper and steel plates were placed in a freezer at about -4.degree.
C. for about 4 hours.
[0397] Oil bleed testing was conducted at a low temperature because
rubber molecules are known to constrict at low temperatures. Thus,
in theory, when a plasticized material is subjected 95 to cooler
temperatures, the attraction of plasticizer to Vander Waals binding
sites on the rubber molecules decreases. Therefore, it has been
theorized that plasticizer-extended materials tend to bleed more at
lower temperatures. However, oil tends to flow more slowly at low
temperatures, suggesting that this theory may not be accurate.
Nevertheless, this theory has been widely accepted. The extreme
condition of the pressure and the freezer was needed for
quantitative evaluation since the example elastomeric gel materials
have the advantage over prior art gel materials of not bleeding at
all at room temperature without pressure, even when placed next to
high capillary action paper. Although John Y. Chen did not report
oil bleed in his patents or patent applications, Applicant's
experience is that Chen's materials have a higher level of oil
bleed than the example elastomeric gel cushioning medium.
[0398] Upon removal from the freezer, each piece of the filter
paper and the samples were immediately weighed again. Percent oil
bleed was then calculated by determining the combined weight
increase of the filter papers, dividing that value by the original
sample weight and multiplying the result by 100.
Example 1
[0399] The material of Example 1 includes eight parts LP 150
mineral oil to one part SEPTON 4055.
1 8:1 Average High Value Percent Elongation 2375 2400 PSI at
Failure 185 190
[0400] In comparison, the! material of Chen's patents that has an
oil to elastomer ratio of 4:1, which should have higher strength
than Applicant's 8:1 material of Example 1, instead exhibits much
lower elongation and PSI at failure (i.e., tensile strength)
values. The material of Example 1 elongates up to about 2,400%,
which is 700% greater elongation than Chen's 4:1, which is capable
of only 1700% elongation (See, e.g., '213 patent, Table 1, col. 6,
lines 18-38). Likewise, the tensile strength at break of Chen's 4:1
gel is only about 4.times.106 dyne/cm', or 58 psi. Thus, the 8:1
material of Example 1 is at least three times as strong as Chen's
4:1. This is an unexpectedly good result since the conventional
wisdom concerning gels is that more oil results in less strength.
Applicant doubled the amount of oil used (8:1 compared to 4:1) but
achieved more than three times the tensile strength of Chen's
material.
Example 2
[0401] The material of Example 2 includes five parts LP 150 mineral
oil to one part SEPTON 4055.
2 5:1 Average High Value Percent Elongation 1975 2030 PSI at
Failure 335 352
[0402] A comparison of the 5:1 material of Example 2 to the 4:1
material of Chen's patents shows that Chen's material exhibits much
lower elongation and PSI at failure (i.e., tensile strength)
values. The material of Example 2 elongates up to about 2,000%,
which is about 300% more than Chen's 4:1, which is capable of only
1700% elongation (See, e.g., '213 patent, Table I, col. 6, lines
18-38). Likewise, the tensile strength at break of Chen's 4:1 gel
is only about 4.times.106 dyne/cm2, which translates to only about
58 psi. Thus, the 5:1 material of Example 2, despite the presence
of about 25% more oil than Chen's 4:1 material, is about
five-and-a-half times as strong as Chen's 4:1.
Example 3
[0403] The material of Example 3 includes three parts LP 150
mineral oil to one part SEPTON 4055.
3 3:1 Average High Value Percent Elongation 1555 1620 PSI at
Failure 404 492
[0404] A consideration of both Example 2, a material having a 5:1
oil to elastomer ratio, and Example 3, a material having a 3:1 oil
to elastomer ratio, indicates that a material with a 4:1 oil to
elastomer ratio would compare very favorably to the gel disclosed
in U.S. Pat. No. 5,508,334, which issued in the name of John Y.
Chen. According to Table I in the '334 patent, Chen's 4:1
KRATON.RTM. G-1651-containing material had a breaking strength
(i.e., tensile strength) value of 4.times.106 dyne/cm2, which
translates to only about 58 psi.
[0405] The elongation at break value was mysteriously omitted from
Table I of the '334 patent and other Chen patents. However,
reference to Table I of Chen's first two issued patents (the '284
and '213 patents) sets the percent elongation of Chen's 4:1
material at about 1700. Applicant suspects that Chen omitted this
data in later patent applications because it was either inaccurate
or Chen's improved materials failed to exhibit improved properties
over his earlier materials.
[0406] In comparison, the percent elongation of a 4:1 example
elastomeric gel material for use in the cushions would be at least
about 1800, exceeding the elongation of Chen's 4:1 material by
about 100% or more. Similarly, the tensile strength of a 4:1
material example for use in the cushions hereof would be at least
about 350 psi, and probably in the 370 to 375 psi range. Thus, a
example elastomenc gel cushioning medium for use in the cushions
with an oil to elastomer ratio of about 4:1 would be about six
times a strong as Chen's most example 4:1 gel.
[0407] The following Examples 4 through 11 have been included to
demonstrate the usefulness of various plasticizing oils in the
example elastomeric gel material.
Example 4
[0408] The material of Example 4 included eight parts of a
plasticizer mixture to one part SEPTON 4055. The eight parts
plasticizer mixture included about 5.3 parts REGALREZ.COPYRGT. 1018
and about 2.8 parts DUOPRIME(g) 90 mineral oil.
4 8:1 Average High Value Percent Elongation 2480 2520 PSI at
Failure 187 195
Example 5
[0409] The material of Example 5 included eight parts of
EDELEX.RTM. 27 oil to one part SEPTON 4055. EDELEX.COPYRGT. 27 has
an aromatic content of about 1%, which would be expected to
slightly decrease the tensile strength of the material.
5 8:1 Average High Value Percent Elongation 2105 2150 PSI at
Failure 144 154 Percent oil bleed 0.34
Example 6
[0410] The material of Example 6 included eight parts of DUOPRIMEO
55 mineral oil to one part SEPTON 4055.
6 8:1 Average High Value Percent Elongation 1940 2055 PSI at
Failure 280 298 Percent oil bleed 0.29
Example 7
[0411] The material of Example 7 included eight parts of
DUOPRIME.RTM. 70 mineral oil to one part SEPTON 4055.
7 8:1 Average High Value Percent Elongation 2000 2030 PSI at
Failure 250 275 Percent oil bleed 0.41
Example 8
[0412] The material of Example 8 included eight parts of
DUOPRIME.RTM. 90 mineral oil to one part SEPTON 4055.
8 8:1 Average High Value Percent Elongation 2090 2125 PSI at
Failure 306 311 Percent oil bleed 0.35
Example 9
[0413] The material of Example 9 included eight parts of
DUOPRIME.RTM. 200 mineral oil to one part SEPTON 4055.
9 8:1 Average High Value Percent Elongation 1970 2040 PSI at
Failure 200 228 Percent oil bleed 0.20
Example 10
[0414] The material of Example 10 included eight parts of
DUOPRIME.RTM. 350 mineral oil to one part SEPTON 4055.
10 8:1 Average High Value Percent Elongation 2065 2080 PSI at
Failure 267 270 Percent oil bleed 0.21
Example 11
[0415] The material of Example 11 included eight parts of
DUOPRIME.RTM. 500 mineral oil to one part SEPTON 4055.
11 8:1 Average High Value Percent Elongation 1995 2075 PSI at
Failure 194 223 Percent oil bleed 0.17
Example 12
[0416]
12 Component Generic Class Amount (grams) Septon 4055 A-B-A
copolymer 227.0 Duoprime 500 oil Plasticizing oil 2,722.0 Irganox
1010 Antioxidant 4.5 Irgafos 168 Antioxidant 4.5 Safoam FP-40
Foaming agent 14.0 Lamp Black Colorant and Foam Bubble 1.5
Nucleating Agent
[0417] Applicant began foaming the example elastomeric gel material
to reduce its specific gravity by heating it until the SAFOAM began
to degenerate and create C02 gas. DUOPRIME 500 oil was selected for
use in the example because of its high viscosity (i.e., it would
help hold a bubble longer than a lower viscosity oil). The
components were compounded in an injection molding machine
according to one example melt blending method. The original mixture
included 3.40 g SAFOAM. When half of the SAFOAM appeared to have
been consumed, 3.40 g more was added. Another 7.20 g of SAFOAM was
added when half of the SAFOAM again appeared to have been consumed.
Temperatures along the injection molding screw ranged from about
280.degree. F. at the point of insertion to about 240.degree. F. at
the nozzle. The material of Example 12 had closed cells of fairly
consistent density.
Example 13
[0418]
13 Component Generic Class Amount (grams) Septon 4055 A-B-A
copolymer 227.0 Duoprime 500 oil Plasticizing oil 2,722.0 Irganox
1010 Antioxidant 1.5 Irgafox 168 Antioxidant 1.5 Expancell DE-80
Microspheres 500.0 Orange Colorant 2.0
[0419] Applicant has also used microspheres to reduce the specific
gravity of the example elastomeric gel cushioning medium. Acrylic
microspheres were used in the material of Example 13. The
components were premixed, then compounded in an injection molding
machine screw. Temperatures along the injection molding screw
ranged from about 260.degree. F. at the point of insertion to about
220.degree. F. at the nozzle. Surprisingly, the microspheres were
not deformed by the high shear and high temperatures of the
injection molding machine. The resulting material was very light,
with microspheres consistently dispersed therethrough.
Example 14
[0420]
14 Component Generic Class Amount (grams) Septon 4055 A-B-A
copolymer 114.0 Kraton G-1701 A-B copolymer 5.8 Regalrez 1018
Plasticizing resin 340.0 Edelex 45 Plasticizing oil 225.0 Talc Talc
20.4 Vestenamer 8012 Tor rubber 11.5 Expancell DU-80 Microspheres
0.5 Safoam FP-40 Foaming agent 10.0 Irganox 1010 Antioxidant 3.0
Irgafos 168 Antioxidant 3.0 Boiled Linseed Oil 8.0 Green Colorant
2.0
[0421] In the material of Example 14, Applicant used KRATON.RTM.
G-1701, manufactured by Shell Chemical Co., to reduce oil bleed.
R:EGALREZ.RTM. 1018 was used as a plasticizer and to reduce oil
bleed from the material. Talc was included in the material of
Example 14 to act as a nucleating agent during foaming of the
material. Since talc migrates to the surface of the material, it is
also useful as a surface detackifier. Talc may also be used as a
filler in the material. VESTENAMER 8012, sold by Mils America Inc.
of Piscataway, N.J., is a transpolyoctylene rubber (tor) which is
useful for reducing oil bleed and reducing melt viscosity of the
example elastomeric gel material. Boiled linseed oil is believed to
reduce the melt viscosity and tackiness of the material and to
accelerate the migration of particulate matter to the material's
surface. Applicant used both microspheres and foaming agents in the
material of Example 14. Although acrylic microspheres reduce the
specific gravity of the example elastomeric gel material, they
increase the stiffness of the material, though not as much as
glass, ceramic, or other rigid microspheres would.
[0422] The closed cell foaming and the microsphere dispersion of
the material of Example 14 were consistent. The material was soft
and light-weight. The components were well compounded. In addition,
the material of Example 14 did not have an oily feel and exhibited
no plasticizer bleedout at room temperature.
[0423] Additives such as colorants, flame retardants, detackifiers
and other additives may be included in the example elastomeric gel
cushioning medium. Various formulations of the example elastomeric
gel material may be tailored to achieve differing levels of
softness, strength, tackiness and specific gravity as desired.
Examples 1 through 11 illustrate the surprisingly high elongation
and tensile strength of the material. Many embodiments of the
example elastomeric material, of which the preceding examples are
representative, exhibit physical properties vastly superior to
those of John Y. Chen's material, which Applicant believes to be
the closest and best prior art. A chemical explanation for the
superior results is provided below.
[0424] Examples 15 through 35 are other formulations of the example
elastomeric gel cushioning medium for use in the cushions. The
formulations of Examples 15 through 35 were compounded using a ZE25
TIEBAR AIR COOLED TWIN SCREW EXTRUDER with a 35:1 L/D ratio
according to a example melt blending method. Temperatures along the
screws were in the range of about 130.degree. C. to about
170.degree. C. at the hopper to about 100.degree. C. to about
130.degree. C. at the nozzle.
Example 15
[0425]
15 Component Generic Class Amount (grams) Septon 4055 A-B-A
copolymer 50.04 LP-150 Plasticizing oil 250.0 Irganox 1010
Antioxidant 1.5 Irgafos 168 Antioxidant 1.5
Example 16
[0426]
16 Component Generic Class Amount (grams) Septon 4055 A-B-A
copolymer 83.25 LP-150 Plasticizing oil 250.00 Irganox 1010
Antioxidant 1.5 Irgafos 168 Antioxidant 1.5
Example 17
[0427]
17 Component Generic Class Amount (grams) Septon 4055 A-B-A
copolymer 50.04 Kadol Plasticizing oil 250.00 E17 Antioxidant
(vitamin E) 6.26
Example 18
[0428]
18 Component Generic Class Amount (grams) Septon 4055 A-B-A
copolymer 250.00 Duoprime 90 Plasticizing oil 1,250.00 E17
Antioxidant (vitamin E) 6.30
Example 19
[0429]
19 Component Generic Class Amount (grams) Septon 4055 A-B-A
copolymer 250.00 LP-150 A-B-A copolymer 1,250.00 E17 Antioxidant
(vitamin E) 6.25
EXHIBIT 20
[0430]
20 Component Generic Class Amount (grams) Septon 4055 A-B-A
copolymer 350.00 Regalrez 1018 Plasticizing resin 262.51 C23 to C27
Alkane Wax Plasticizer 35.00 LP-150 Plasticizing oil 287.60 E 17
Antioxidant (vitamin E) 14.00 Ethosperse 52.50 White Colorant 10.50
Yellow Colorant 0.70 Red Colorant 0.03
Example 21
[0431]
21 Weight % Component Generic Class of Total SEPTON .RTM. 4055
Triblock copolymer 11.89 KRATON .RTM. G 1701 Diblock copolymer 0.24
LP-150 mineral oil Plasticizer 73.87 Astor Slack Wax 2050
Plasticizer 8.33 Alkane Wax C 25-27 Plasticizer 0.59 IRGANOX .RTM.
1010 Antioxidant 0.42 IRGAFOS .RTM. 168 Antioxidant 0.42 IRGANOX
.RTM. E17 Antioxidant 0.42 TETRAGLYME Anti-bleed, anti-tack
additive 1.19 PQ 6546 Acrylic Microspheres 1.44 Rocket Red Colorant
1.19
Example 22
[0432]
22 Weight % Component Generic Class of Total SEPTON .RTM. 4055
Triblock copolymer 14.86 KRATON9 G 1701 Diblock copolymer 0.30
LP-150 mineral oil Plasticizer 71.01 Astor Slack Wax 2050
Plasticizer 6.69 Alkane Wax C 25-27 Plasticizer 0.58 IRGANOX .RTM.
1010 Antioxidant 0.52 IRGAFOS .RTM. 168 Antioxidant 0.52 IRGANOX
.RTM. E17 Antioxidant 0.52 TETRAGLYME Anti-bleed, anti-tack
additive 1.34 PQ 6546 Acrylic Microspheres 1.44 Rocket Red Colorant
2.23
Example 23
[0433]
23 Weight % Component Generic Class of Total SEPTON .RTM. 4055
Triblock copolymer 16.66 KRATON .RTM. G 1701 Diblock copolymer 0.33
LP-150 mineral oil Plasticizer 67.48 Astor Slack Wax 2050
Plasticizer 7.50 Alkane Wax C 25-27 Plasticizer 0.67 IRGANOX .RTM.
1010 Antioxidant 0.58 IRGAFOS .RTM. 168 Antioxidant 0.58 IRGANOX
.RTM. E17 Antioxidant 0.58 TETRAGLYME Anti-bleed, anti-tack
additive 1.50 PQ 6546 Acrylic Microspheres 1.62 Rocket Red Colorant
2.50
Example 24
[0434]
24 Weight % Component Generic Class of Total SEPTON .RTM. 4055
Triblock copolymer 13.18 KRATON .RTM. G 1701 Diblock copolymer 0.26
LP-150 mineral oil Plasticizer 75.12 Astor Slack Wax 2050
Plasticizer 5.27 Alkane Wax C 25-27 Plasticizer 0.33 IRGANOX .RTM.
1010 Antioxidant 0.46 IRGAFOS .RTM. 168 Antioxidant 0.46 IRGANOX
.RTM. E 17 Antioxidant 0.46 TETRAGLYME Anti-bleed, anti-tack
additive 1.19 PQ 6546 Acrylic Microspheres 1.62 Horizon Blue
Colorant 1.65
Example 25
[0435]
25 Weight % Component Generic Class of Total SEPTON .RTM. 4055
Triblock copolymer 11.07 KRATON .RTM. G 1701 Diblock copolymer 0.22
LP-150 mineral oil Plasticizer 76.89 Astor Slack Wax 2050
Plasticizer 5.54 Alkane Wax C 25-27 Plasticizer 0.55 IRGANOX .RTM.
1010 Antioxidant 0.39 IRGAFOS .RTM. 168 Antioxidant 0.39 IRGANOX
.RTM. E 17 Antioxidant 0.39 Amyl Formate Clarity enhancer 0.55
(supplied by Aldrich) TETRAGLYME Anti-bleed, anti-tack additive
1.66 PQ 6546 Acrylic Microspheres 0.97 Horizon Blue Colorant
1.38
Example 26
[0436]
26 Weight % Component Generic Class of Total SEPTON .RTM. 4055
Triblock copolymer 14.40 KRATON .RTM. G 1701 Diblock copolymer 0.29
LP-150 mineral oil Plasticizer 74.50 Astor Slack Wax 2050
Plasticizer 4.80 Alkane Wax C 25-27 Plasticizer 0.50 IRGANOX .RTM.
1010 Antioxidant 0.50 IRGAFOS .RTM. 168 Antioxidant 0.50 IRGANOX
.RTM. E17 Antioxidant 0.50 TETRAGLYME Anti-bleed, anti-tack
additive 1.44 PQ 6546 Acrylic Microspheres 0.97 Signal Green
Colorant 1.58
Example 27
[0437]
27 Weight % Component Generic Class of Total SEPTON .RTM. 4055
Triblock copolymer 13.37 KRATON .RTM. G 1701 Diblock copolymer 0.27
LP-150 mineral oil Plasticizer 74.88 Astor Slack Wax 2050
Plasticizer 5.35 Alkane Wax C 25-27 Plasticizer 3.34 IRGANOX .RTM.
1010 Antioxidant 0.47 IRGAFOS .RTM. 168 Antioxidant 0.47 IRGANOX
.RTM. E17 Antioxidant 0.47 TETRAGLYME Anti-bleed, anti-tack
additive 1.34 Amyl Formate Clarity Enhancer 0.40 PQ 6546 Acrylic
Microspheres 0.99 Signal Green Colorant 1.47
Example 28
[0438]
28 Weight % Component Generic Class of Total SEPTON .RTM. 4055
Triblock copolymer 8.14 KRATON .RTM. G 1701 Diblock copolymer 0.16
LP-150 mineral oil Plasticizer 80.76 Astor Slack Wax 2050
Plasticizer 6.51 Alkane Wax C 25-27 Plasticizer 0.49 IRGANOX .RTM.
1010 Antioxidant 0.28 IRGAFOS .RTM.168 Antioxidant 0.28 IRGANOX
.RTM. E17 Antioxidant 0.28 TETRAGLYME Anti-bleed, anti-tack
additive 1.22 PQ 6546 Acrylic Microspheres 0.97 Blaze Orange
Colorant 0.90
Example 29
[0439]
29 Weight % Component Generic Class of Total SEPTON .RTM. 4055
Triblock copolymer 8.12 KPATON .RTM. G 1701 Diblock copolymer 0.16
LP-150 mineral oil Plasticizer 80.60 Astor Slack Wax 2050
Plasticizer 6.50 Alkane Wax C 25-27 Plasticizer 0.49 IRGANOX .RTM.
1010 Antioxidant 0.28 IRGAFOS .RTM. 168 Antioxidant 0.28 IRGANOX
.RTM. E 17 Antioxidant 0.28 TETRAGLYME Anti-bleed, anti-tack
additive 1.22 Amyl Formate Clarity Enhancer 0.20 PQ 6546 Acrylic
Microspheres 0.97 Blaze Orange Colorant 0.90
Example 30
[0440]
30 Weight % Component Generic Class of Total SEPTON .RTM. 4055
Triblock copolymer 12.10 KRATON .RTM. G 1701 Diblock copolymer 0.30
LP-150 mineral oil Plasticizer 84.47 IRGANOXID 1010 Antioxidant
0.18 IRGAFOS .RTM. 168 Antioxidant 0.18 FC-10 fluorochemical
alcohol Bleed-reducing additive 0.18 Strong Magenta Colorant 0.36
Horizon Blue Colorant 0.36 PQ 6545 Acrylic Microspheres 1.62
Example 31
[0441]
31 Weight % Component Generic Class of Total SEPTON .RTM. 4055
Triblock copolymer 19.69 LP-150 mineral oil Plasticizer 78.78
IRGANOXt 1010 Antioxidant 0.20 IRGAFOS .RTM. 168 Antioxidant 0.20
DYNTAMAR .RTM. FX 9613 Bleed-reducing additive 0.15 091DU80 Acrylic
Microspheres 0.98
Example 32
[0442]
32 Weight % Component Generic Class of Total SEPTON .RTM. 4055
Triblock copolymer 19.60 LP-150 mineral oil Plasticizer 78.39
IRGANOX .RTM. 1010 Antioxidant 0.19 IRGAFOS .RTM. 168 Antioxidant
0.20 DYNAMAR .RTM. FX 9613 Bleed-reducing additive 0.15 091 DU80
Acrylic Microspheres 1.47
Example 33
[0443]
33 Weight % Component Generic Class of Total SEPTON .RTM. 4055
Triblock copolymer 28.38 LP-150 mineral oil Plasticizer 70.92
IRGANOX .RTM. 1010 Antioxidant 0.28 IRGAFOS .RTM. 168 Antioxidant
0.28 ZONYL .RTM. BA-N Bleed-reducing additive 0.14
Example 34
[0444]
34 Weight % Component Generic Class of Total SEPTON .RTM. 4055
Triblock copolymer 23.43 LP-150 mineral oil Plasticizer 58.55
IRGANOX .RTM. 1010 Antioxidant 0.23 IRGAFOS .RTM. 168 Antioxidant
0.23 Carbowax Plasticizer, includes 17.56 polar molecules
Example 35
[0445]
35 Weight % Component Generic Class of Total SEPTON .RTM. 4055
Triblock copolymer 15.14 SEPTON .RTM. 4033 Triblock copolymer 3.79
LP-150 mineral oil Plasticizer 80.45 IRGANOX .RTM. 1010 Antioxidant
0.19 IRGAFOS .RTM. 168 Antioxidant 0.19 ZONYL .RTM. BA-N
Bleed-reducing additive 0.15 Horizon Blue Colorant 0.09
[0446] Representative Visco-Elastomeric Gel Formulations
[0447] The following examples have been prepared by Applicant.
Example 36
[0448]
36 Weight % Component Generic Class of Total Septon 4055 A-B-A
copolymer 5.46 Kraton G1701 A-B copolymer 0.55 Irganox 1010
antioxidant 0.16 Ireafos 168 antioxidant 0.16 LP-150 plasticizing
oil 32.77 Regalrez 1018 plasticizing resin 54.62 Kristalex 5140
strengthening resin 0.55 Regalite R101 plasticizing resin 2.73
Regalrez 1139 plasticizing resin 2.73 PQ 6545 added to increase
rebound rate 0.16 microspheres and decrease specific gravity Bright
orange colorant 0.11 aluminum lake
[0449] SEPTON.RTM. 4055 imparts form and strength to the
visco-elastic material. KRATON.RTM. G-1701 is used to facilitate a
more homogeneous blend of the elastomer (A-B-A copolymer) and
plasticizer components. REGALREZ.RTM. 1018, a room temperature
liquid plasticizer, is the primary plasticizer used in the
material. REGALITE.RTM. R101 and REGALREZ.RTM. 1139 are also
plasticizers and modify the tack of the visco-elastic material.
KRISTALEX.RTM. 5140 is believed to impart strength to the styrene
domains or centers of the A-B-A copolymer. It is also believed to
have some plasticizing abilities when used in combination with
A-B-A copolymers. IRGANOX.RTM. 1010 and IRGAFOS.RTM.) 168 are
antioxidants. The material of Example 36 was made as an early
experiment. Consequently, LP-150, a plasticizing oil, was used in
combination with the resin plasticizers.
[0450] The material of Example 36 was prepared by premixing the
components and melt blending them in an injection molding machine
according to one example method for compounding the example gel
cushioning medium. The material was very tacky and readily
deformable, had very quick rebound and was very soft. Applicant
believes that the very quick rebound rate is caused by the presence
of plasticizing oil and microspheres. The specific gravity of the
material was about 0.40.
Example 37
[0451]
37 Weight % Component Generic Class of Total Septon 8006 A-B-A
copolymer 2.42 Septon 4055 A-B-A copolymer 2.42 Kraton G1701 A-B
copolymer 0.48 Irganox 1010 antioxidant 0.15 Irgafos 168
antioxidant 0.15 Regalrez 1018 plasticizing resin 87.18 Kxistalex
5140 strengthening resin 0.48 Regalite R101 plasticizing resin 2.42
Regalrez 1139 plasticizing resin 2.42 PQ 6545 added to increase
rebound rate 1.39 microspheres and decrease specific gravity Bright
orange colorant 0.24 aluminum lake Dow Corning rubber additive 0.24
200 silicone
[0452] In the material of Example 37, SEPTON.RTM. 8006 was used in
combination with SEPTON.RTM. 4055 to provide some form, but a
softer visco-elastic material. Silicone was added to detackify the
material. The material of 5xample 37 was prepared by premixing the
components and melt blending them in an injection molding machine
according to a example method for compounding the example gel
material. The material was slightly tacky and readily deformable,
had slow rebound and moderate stiffness. The use of silicone seems
to have decreased the tackiness of the material. The specific
gravity of the material was about 0.30.
Example 38
[0453]
38 Weight % Component Generic Class of Total Septon 8006 A-B-A
copolymer 2.45 Septon 4055 A-B-A copolymer 2.45 Kraton G1701 A-B
copolymer 0.49 Iroanox 1010 antioxidant 0.15 Irgafos 168
antioxidant 0.15 Regalrez 1018 plasticizing resin 88.38 Kristalex
5140 strengthening resin 0.49 Regalite R101 plasticizing resin 2.46
Regalrez 1139 plasticizing resin 2.46 PQ 6545 added to increase
rebound rate 0.28 microspheres and decrease specific gravity Bright
orange colorant 0.25 aluminum lake
[0454] The material of Example 38 was prepared by premixing the
components and melt blending them in an injection molding machine
according to a example method for compounding the example gel
material for use in the cushions. The material was very tacky and
readily deformable, had a slow to moderate rebound rate and was
extremely soft. The specific gravity of the material was about
0.65. 13
Example 39
[0455]
39 Weight % Component Generic Class of Total Septon 8006 A-B-A
copolymer 2.45 Septon 4055 A-B-A copolymer 2.45 Kraton G 1701 A-B
copolymer 0.49 Irganox 1010 antioxidant 0.15 Irgafos 168
antioxidant 0.15 Regalrez 1018 plasticizing resin 88.06 Kristalex
5140 strengthening resin 0.49 Regalite R101 plasticizing resin 2.45
Regalrez 1139 plasticizing resin 2.45 PQ 6545 added to increase
rebound rate 0.64 microspheres and decrease specific gravity Bright
orange colorant 0.24 aluminum lake
[0456] The material of Example 39 was prepared by premixing the
components and melt blending them in an injection molding machine
according to a example compounding method. The material was very
tacky and readily deformable, had moderate rebound and moderate
softness. The specific gravity of the material was about 0.44.
Example 40
[0457]
40 Weight % Component Generic Class of Total Septon 8006 A-B-A
copolymer 2.43 Septon 4055 A-B-A copolymer 2.43 Kraton G 1701 A.-B
copolymer 0.49 Irganox 1010 antioxidant 0.15 Irgafos 168
antioxidant 0.15 Regalrez 1018 plasticizing resin 87.51 Kristalex
5140 strengthening resin 0.49 Regalite R101 plasticizing resin 2.43
Regalrez 1139 plasticizing resin 2.43 PQ 6545 added to increase
rebound rate 1.26 microspheres and decrease specific gravity Bright
orange colorant 0.24 aluminum lake
[0458] The material of Example 40 was prepared by premixing the
components and melt blending them in an injection molding machine
according to a example compounding method. The material was tacky
and readily deformable, had very quick rebound and moderate
softness. The specific gravity of the material was about 0.28.
Example 41
[0459]
41 Weight % Component Generic Class of Total Septon 8006 A-B-A
copolymer 2.44 Septon 4055 A-B-A copolymer 2.44 Kraton G1701 A-B
copolymer 0.49 Irganox 1010 antioxidant 0.15 Irgafos 168
antioxidant 0.15 Regalrez 1018 plasticizing resin 87.78 Kristalex
5140 strengthening resin 0.49 Regalite R101 plasticizing resin 2.44
Regalrez 1139 plasticizing resin 2.44 PQ 6545 microspheres added to
increase rebound rate 0.95 and decrease specific gravity
Colorant-bright orange 0.24 aluminum lake
[0460] The material of Example 41 was prepared by premixing the
components and melt blending them in an injection molding machine
according to a example compounding method. The material was very
tacky and readily deformable, had slow rebound and little
stiffness. The specific gravity of the material was about 0.37.
Example 42
[0461]
42 Weight % Component Generic Class of Total Septon 4033 A-B-A
copolymer 0.29 Septon 8006 A-B-A copolymer 4.05 Kraton G1701 A-B
copolymer 0.09 Irganox 1010 antioxidant 0.12 Irgafos 168
antioxidant 0.12 Regalrez 1018 plasticizing resin 86.73 Kristalex
5140 plasticizing resin 0.87 Regalite R101 plasticizing resin 2.02
Regalrez 1139 plasticizing resin 2.02 Vistanex LM-MS plasticizing
resin 2.89 PQ 6545 microspheres added to increase rebound rate 0.37
and decrease specific gravity Safoam FP-powder blowing agent
0.43
[0462] In the material of Example 42, SEPTON.RTM. 4033 was used as
a lower molecular weight polymer to help trap foam bubbles. A
greater weight percentage of SEPTON.RTM. 8006 was used to 114
provide a visco-elastomeric material which was softer than the
materials of the preceding examples. VISTANEX.RTM. LM-MS was also
added to determine whether its presence improved the material's
ability to retain foam bubbles.
[0463] In preparing the material of Example 42, the solid resins
were first crushed and premixed. The VISTANEX.RTM. LM-MS was heated
for thirty minutes in an oven at about 150 to 200.degree. C. The
REGALREZ.RTM. and VISTANEX.RTM. were then mixed together with heat
until the VISTANEX.RTM. appeared to be completely solvated.
[0464] The components of the material of Example 42 were then melt
blended in an injection molding machine according to a example
compounding method. The -material was very tacky and readily
deformable, had very slow rebound and was very soft. The use of
VISTANEX.RTM. LM-MS appears to have decreased the rebound rate of
the material. The specific gravity of the material was about
0.61.
Example 43
[0465]
43 Weight % Component Generic Class of Total Septon 4033 A-B-A
copolymer 0.29 Septon 8006 A-B-A copolymer 4.05 Kraton G1701 A-B
copolymer 0.09 Irganox 1010 antioxidant 0.12 Irgafox 168
antioxidant 0.12 Vistanex LM-MS Plasticizing resin 2.90 Regalrez
1018 Plasticizing resin 86.85 Kristalex 5140 Strengthening resin
0.87 Regalite R101 Plasticizing resin 2.03 Regalrez 1139
Plasticizing resin 2.03 PQ 6545 microspheres Added to increase
rebound rate 0.67 and decrease specific gravity
[0466] In preparing the material of Example 43, the crystallized
(not readily flowable at room temperature) resins were first
crushed and premixed. The VISTANEX.RTM. LM-MS was heated for thirty
minutes in oven at about 150 to 200.degree. C. The REGALREZO and
VISTANEX.RTM. were then mixed together with heat until the
VISTANEX.RTM. appeared to be completely solvated. The components of
the material of Example 43 were then melt blended in an injection
molding machine according to a example method for compounding the
example gel cushioning media. The material was very tacky and
readily deformable, had extremely slow, incomplete rebound and was
very soft. The specific gravity of the material was about 0.47.
Example 44
[0467]
44 Weight % Component Generic Class of Total Septon 4077 A-B-A
copolymer 4.67 Irganox 1010 antioxidant 0.30 Irgafos 168
antioxidant 0.30 Regalrez 1018 plasticizing resin 83.25 Vistanex
LM-MS plasticizing resin 1.81 Kristale 5140 plasticizing resin 0.96
Regalite R101 plasticizing resin 1.93 Regalrez 1139 plasticizing
resin 1.93 PQ 6545 microspheres added to increase rebound rate 0.60
and decrease specific gravity Glycerin detackifying agent 4.25
[0468] SEPTON.RTM. 4077 was included in the material of Example 44
to provide form and strength to the material, yet provide a softer
material than that using SEPTONO 4055. The crystallized (not
readily flowable at room temperature) resins of Example 44 were
first crushed and premixed. The VISTANEX.RTM. LM-MS was heated for
thirty minutes in oven at about 150 to 200.degree. C. The
REGALREZ.RTM. and VISTANEX.RTM. were then mixed together with heat
until the VISTANEXV appeared to be completely solvated.
[0469] The remaining components were then quickly mixed and melt
blended in an injection molding machine according to a example
compounding method. The material was very tacky (but less than a
comparable material without the glycerin), readily deformable, had
extremely slow, incomplete rebound and moderate softness. Use of
SEPTON.RTM. 4077 appears to have resulted in a material which is
softer than those which include SEPTON.RTM. 4055 as the only
plasticizer, but stiffer than materials of the previous examples
which have a combination of copolymers. The specific gravity of the
material was about 0.40.
Example 45
[0470]
45 Weight % Component Generic Class of Total Septon 1077 A-B-A
copolymer 4.67 Irganox 1010 antioxidant 0.30 Irgafos 168
antioxidant 0.30 Regalrez 1018 plasticizing resin 83.25 Vistane
LM-MS plasticizing resin 1.81 Kristalex 5140 strengthening resin
0.96 Regalite R101 plasticizing resin 1.93 Regalrez 1139
plasticizing resin 1.93 PQ 6545 microspheres added to increase
rebound rate 0.60 and decrease specific gravity Glycerin
detackifying agent 4.25
[0471] Glycerine was added to detackify the material of Example 45.
In preparing the material of Example 45, the crystallized (not
readily flowable at room temperature) resins were first crushed and
premixed. The VISTANEX.RTM. LM-MS was heated for thirty minutes in
oven at about 150 to 200.degree. C. The REGALREZ.RTM. and
VISTANEX.RTM. were then mixed together with heat until the
VISTANEX.RTM. appeared to be completely solvated.
[0472] The remaining components were then mixed thoroughly and melt
blended in an injection molding machine according to a example
compounding method. The material was moderately tacky and readily
deformable, had quick rebound and was soft. Glycerine appears to
have reduced the tackiness of the material. The specific gravity of
the material was about 0.42.
Example 46
[0473]
46 Weight % Component Generic Class of Total Septon 4055 A-B-A
copolymer 2.47 Septon 8006 A-B-A copolymer 2.47 Kraton G 1701 A-B
copolymer 0.49 Irganox 1010 antioxidant 0.15 Irgafos 168
antioxidant 0.15 Regalrez 1018 plasticizing resin 88.85 Kristalex
5140 strengthening resin 0.49 Regalite 8101 plasticizing resin 2.47
Regalrez 1139 plasticizing resin 2.47
[0474] The material of Example 46 was prepared by premixing the
components and melt blending them in an injection molding machine
according to a example compounding method. The material was
extremely tacky and readily deformable, had slow rebound and was
very soft. The specific gravity of the material was about 0.37.
Example 47
[0475]
47 Weight % Component Generic Class of Total Septon 4055 A-B-A
copolymer 2.35 Septon 8006 A-B-A copolymer 2.35 Kraton G 1701 A-B
copolymer 0.47 Irganox 1010 antioxidant 0.14 Irgafos 168
antioxidant 0.14 Regalrez 1018 plasticizing resin 84.36 Kristalex
5140 strengthening resin 0.47 Regalite R101 plasticizing resin 2.34
Regalrez 1139 plasticizing resin 2.34 PQ 6545 microspheres added to
increase rebound rate 0.36 and decrease specific gravity Glycerin
detackifying agent 4.69
[0476] The material of Example 47 was prepared by premixing the
components and melt blending; them in an injection molding machine
according to a example method for compounding the example gel
cushioning materials for use in the cushioning elements hereof. The
material was very tacky and readily deformable, had slow rebound
and little stiffness.
Example 48
[0477]
48 Weight % Component Generic Class of Total Septon 4055 A-B-A
copolymer 2.39 Septon 8006 A-B-A copolymer 2.39 Kraton G 1701 A-B
copolymer 0.48 Irganox 1010 antioxidant 0.14 Irgafos 168
antioxidant 0.14 Regalrez 1018 plasticizing resin 80.21+ (see
premix below) Kristalex 5140 strengthening resin 0.48 Regalitc R101
plasticizing resin 2.39 Regalrez 1139 plasticizing resin 2.39
Premixed 9.00 microspheres PQ 6545 added to increase rebound 11.76%
of microspheres rate and decrease specific premix (1.06) gravity
Regalrez 1018 88.24% of premix (7.94)
[0478] The material of Example 48 was prepared by premixing the
components blending them in an injection molding machine according
to a example compounding method. The material was extremely tacky
and readily deformable, had slow rebound and little stiffness. The
specific gravity of the Example 48 material was about 0.63.
[0479] Pre-blending the microspheres with REGALREZ.RTM. 1018 was,
in part, advantageous because it reduced the amount of microspheres
that were dispersed into the air during agitation, making the
microspheres easier to handle.
Example 49
[0480] A visco-elastic material was made which included four parts
REGALREZ.RTM. 1018 and melt (plasticizing resin), four parts
HERCULES.RTM.) Ester Gum I OD (plasticizing resin) and one part
SEPTON 4055 (A-B-A copolymer). The components were mixed, placed in
an oven and heated to about 300.degree. F. After all of the
components became molten, they were mixed, poured onto a flat
surface and cooled. The material had little tack, deformed under
pressure, was very stiff but readily deformable with light
sustained pressure, and had an extremely slow rate of rebound.
Example 50
[0481]
49 Weight % Component Generic Class of Total Septon 4055 A-B-A
copolymer 11.75 Ester Gum 10D visco-elasticity enhancer 35.25
Regalrez 1018 plasticizing resin 29.38 Kristalex 5140 strengthening
resin 1.18 Foral 85 strengthening resin 3.53 LP-150 oil
plasticizing oil 14.10 Ethosperse LA-23 foaming facilitator 3.53
Irganox 1010 antioxidant 0.35 Irgafos 168 antioxidant 0.35 Aluminum
Lake Colorant 0.59 (Rocket red)
[0482] The material of Example 50 was prepared by premixing the
components and melt blending them in an injection molding machine
according to a example compounding method. The material was
moderately tacky and deformable under slight, prolonged compressive
force, had extremely slow rebound and was very stiff. FORAL 85,
manufactured by Hercules, is a glycerol ester of hydrogenated resin
that is used primarily as a tackifier. In the example visco-elastic
gel, FORAL 85 acts as a strengthening resin, and is believed to
associate with and bind together the styrene domains. ETHOSPERSE
LA-23, known generically in the art as Laureth-23, is used in the
art as an emulsifier. Laureth-23 facilitates foaming in the gel
materials example for use in the cushions. The other components of
Example 50 have been explained above.
Example 51
[0483]
50 Component Generic Class Amount (grams) Septon 4055 A-B-A
copolymer 80.00 Septon 4077 A-B-A copolymer 80.00 Kraton G-1701 A-B
copolymer 16.00 Regalrez 1018 plasticizing resin 2688.00+ (see
microsphere premix below) Irganox 1010 antioxidant 4.80 Irgafos 168
antioxidant 4.80 Premixed 402.30 microspheres PQ 6545 added to
increase rebound 11.76% of premix microspheres rate and decrease
specific (47.31 g) gravity Regalrez 1018 88.24% of premix (354.99
g)
[0484] The material of Example 51 was prepared by preheating the
REGALREZ.RTM. 1018, mixing all of the components except the
microspheres together, and melt blending the components in a heated
vessel at 295.degree. F. under about one to about four pounds
pressure for about two hours, according to a compounding method.
The mixture was then transferred to another vessel, which was
heated to about 300.degree. F., and the premixed microspheres and
REGALREZ.RTM. 1018 were mixed in by hand. The material was very
tacky and readily deformable, had moderately slow rebound and was
very soft. The specific gravity of the material of Example 51 was
about 0.51. Of the preceding sixteen examples (Examples 36-51),
Applicant example the material of Example 51 because of its extreme
softness and slow to moderate rebound rate. Applicant also liked
the material of Example 50 because of its stiffness, but easy
deformability under sustained pressure, and its extremely slow rate
of reformation.
Example 52
[0485] A visco-elastic material which includes from about one to
about 30 weight percent of a triblock copolymer and about 70 to
about 99 weight percent of a plasticizer, said weight percentages
being based upon the total weight of the visco-elastic material.
The visco-elastic material may also include up to about 2.5 weight
percent of a primary antioxidant and up to about 1.5 weight percent
of a secondary antioxidant, said weight percentages based upon the
weight of the triblock copolymer.
[0486] The following are additional examples of formulations that
can be used to make gelatinous elastomers.
Example 53
[0487]
51 Component Generic Class Weight % of Total SEEES copolymer 75
Mineral oil plasticizer 25
[0488] SEEES is used to designated
styrene-ethyene-ethyene-ethyene-propyle- ne-styrene.
Example 54
[0489]
52 Component Generic Class Weight % of Total SEEES copolymer 80
Mineral oil plasticizer 20 22
Example 55
[0490]
53 Component Generic Class Weight % of Total SEEES copolymer 83
Mineral oil plasticizer 17
Example 56
[0491]
54 Component Generic Class Weight % of Total SEEES copolymer 77
Mineral oil plasticizer 23
Example 57
[0492]
55 Component Generic Class Weight % of Total SEEES copolymer 75
Mineral oil plasticizer 25
Example 58
[0493]
56 Component Generic Class Weight % of Total SEEES copolymer 67
Mineral oil plasticizer 33
Example 59
[0494]
57 Component Generic Class Weight % of Total SEEES copolymer 60
Mineral oil plasticizer 40
Example 60
[0495]
58 Component Generic Class Weight % of Total SEPS copolymer 90
Mineral oil plasticizer 10
[0496] SEPS is used to designate
styrene(ethylene/propylene-)styrene which preferably will have a
weight average molecular weight of about 300,000 or more.
Example 61
[0497]
59 Component Generic Class Weight % of Total SEPS copolymer 80
Mineral oil plasticizer 20
Example 62
[0498]
60 Component Generic Class Weight % of Total SEPS copolymer 70
Mineral oil plasticizer 30
Example 63
[0499]
61 Component Generic Class Weight % of Total SEPS copolymer 67
Mineral oil plasticizer 33
Example 64
[0500]
62 Component Generic Class Weight % of Total SEPS copolymer 60
Mineral oil plasticizer 40
Example 65
[0501]
63 Component Generic Class Weight % of Total SEPS copolymer 50
Mineral oil plasticizer 50
Example 66
[0502]
64 Component Generic Class parts by weight SEPS (4055) copolymer 80
Resin (Regalrez 1018) plasticizer 10 Irganox 1010 antioxidant 0.15
2 Irgaphos 168 antioxidant 0.15 3
Example 67
[0503]
65 Component Generic Class parts by weight SEPS (4055) copolymer 10
Mineral oil plasticizer 20 Irganox 1010 antioxidant 0.15 Irgaphos
168 antioxidant 0.15
Example 69
[0504]
66 Component Generic Class parts by weight SEPS (4055) copolymer 10
Mineral oil plasticizer 120 Irganox 1010 antioxidant 0.15 Irganox
168 antioxidant 0.15
[0505] Each of examples 67-69, while having many uses, are example
for use in causing standard prior art open cell foam, such as
polyurethane foam and latex foam rubber, to become a viscoelastic
foam. This is done by coating the open cells of the foam with a
stick substance such as that of the examples. The tacky substance
should not be adhesive, however, or the foam will not return to its
original shape after deformation. It is example that the tacky
substance be a solid or a gel rather than a liquid to eliminate the
need to contain the coated foam in a bladder. It is also example
that the tacky substance be an elastomer so that it can flex and
bend with the foam. Use of a resin as a plasticizer creates a
delayed rebound viscoelastic foam. The tacky substance, such as
that of examples 67-69, can be used to coat foam by any of a
variety of methods. For example, solvating the gel in a liquid and
soaking the foam will work. Or the gel may be heated to become a
liquid and then forced into the foam. If a foam is coated with a
low stiffness gel, then a viscoelastic foam with excellent elastic
properties is the result. Alternatively, the foam may be cut into
small pieces, the small pieces saturated with a gel, the excess gel
removed from the gel, and the mass of gel-coated foam allowed to
dry or cool so that the gel will solidify. The gel then creates a
structure holding the pieces of foam together. Such a cushioning
material tends to have excellent elasticity and strength.
Example 70
[0506]
67 Component Generic Class parts by weight SEPS (4055) copolymer 1
Resin (Regalrez 1018) plasticizer 10 Irganox 1010 antioxidant 0.15
Irganox 168 antioxidant 0.15
Example 71
[0507]
68 Component Generic Class parts by weight SEPS (4055) copolymer 1
Resin (Regalrez 1018) plasticizer 18 Irganox 1010 antioxidant
0.25
[0508] Outer coating of short rayon fibers to eliminate
tackiness.
[0509] The above examples 70 and 71 provide a slow rebound
viscoelastomer gel. Gel of the formula from Example 71 was formed
into a rectangular shape of dimensions 2 cm.times.2 cm.times.7 cm.
The rebound of the material was then tested. When the rectangular
shape was stretched along its length (from 7 cm) to a length of 20
cm, the following was found: in one second, the gel rebounded to a
length of 13 cm; in two seconds (total) it rebounded to a length of
10 cm; in four second; 3 (total) it rebounded to a length of 8 em;
and in nine seconds (total) it rebounded to substantially its
original shape. These slow rebound times cause the inventor to
classify it as a slow rebound viscoelastomer. Similarly slow
rebound was found on compression. When the rectangular shape was
compressed along its length (originally 7 cm) to a length of 3 cm,
and released, after one second it rebounded to a length of 5 cm;
after two seconds (total) it rebounded to a length of 6 cm; after
four seconds (total) it rebounded to a length of 6.5 cm, and after
nine seconds (total) it returned to substantially its original
shape. After five hundred alternate compression and elongation
cycles, the rectangular shaped viscoelastomer of Example 71 had
substantially the same dimensions and shape as before. All of these
tests were run at 25 degrees 10 Clesius.
Example 72
[0510]
69 Component Generic Class parts by weight SEPS (4055) copolymer
1.64 Resin (Regalrez 1018) plasticizer 17.5 Mineral oil (Whitco
LP-200) plasticizer 10 Irganox 1010 antioxidant 0.073
[0511] Outer coating of pressed-on microspheres to eliminate
tackiness.
[0512] A viscoelastomer made according to the formula of Example 72
was formed into a rectangular cube of dimensions 7 cm
(width).times.3 cm (height).times.14 cm (length). Elongation and
compression testing was then performed at 25 degrees Celsius and
the following was found. After elongation of the rectangular cube
along its length to a total length of 30 cm, after one second it
rebounded to a length of 20 cm; after two seconds (total) it
rebounded to a length of 18 cm; after four seconds (total) it
rebounded to a length of 16 cm; and after nine seconds (total) it
rebounded to 127 substantially its original dimensions and shape.
On compression along its length to a reduced total length of 7 cm,
rebound was found to be as follows: after one second, the cube
rebounded to a length of 10 cm; after two seconds (total) it
rebounded to a length of 11.5 cm; after four seconds (total) it
rebounded to a length of 13 cm; after nine seconds (total) it
rebounded to substantially its original dimensions and shape. After
five hundred alternate elongation and compression tests as just
described, the material returned to substantially its original size
and shape.
[0513] The following are viscoelastomer formulations used to reduce
oil bleed and tack that was very problematic in the prior art,
including in the gels of John Y. Chen.
Example 73
[0514]
70 Component Generic Class parts by weight SEPS (4055) copolymer 1
Resin (Regalrez 1018) plasticizer 18 Irganox 1010 antioxidant
0.25
[0515] Outer coating of short rayon or other fibers to eliminate
tackiness.
[0516] It is notable that the example bleed reducing additives of
these example embodiments include a plurality of polarizable sites
thereon, including halogen atoms, nitriles and others. Polarizable
means an atom's ability to respond to a changing electrical field.
Molecules with polarizable atoms are more likely to be attracted to
other molecules by dynamic van der Waals forces, thus reducing
bleed. The bleed reducing additives allow there to be an increase
in the amount of plasticizer used in the material without an
increase in oil bleed. Preferably, the elastomer will include
hydrocarbon chains with polarizable groups thereon, such as
hydrogenated hydrocarbons, nitriles and others. The polarizable
groups are believed to hold the plasticizer close to the copolymer
to reduce bleed. This occurs by the polarizable group attracting a
plasticizer at one end and an elastomer block at the other, thus
maintaining association of plasticizer with elastomer. A
plasticizer can be attached to an elastomer by use of a polarizable
group. It is example that the additive will have a plurality of
polarizable groups. The most example bleed reducing additives are
halogenated hydrocarbon additives such as DYNAM AR PPA-791, DYNAMAR
PPA-790, DYNAMAR FX-9613 and FLUOROADE FC10 Flourochemical alcohol
from 3M Company of St. Paul, Minn. Other additives can be used to
reduce plasticizer exudation. For example, FLUORORAD FC-129,
FC-135, FC-430, FC-722, FC-724, FC-740, FX-8, FX-13, FX-14 and
FX-189 are halogenated hydrocarbons that will serve this purpose.
Others which may be used include XONTLY FSN 100, FSO 100, PFBE
8857A, TM, BA-L, TBC and FTS from DuPont of Wilmington, Del. Witco
Corp. of Houston, Tex. sells halogenated hydrocarbons under the
names EMCOL 4500 and DOSS. Hartwick, Inc. of Akron, Ohio sells
chlorinated polyethylene elastomer (CPE) and chlorinated paraffin
wax. None of these chemicals is marketed as a bleed reducing
additive, however. It is example that processing temperatures just
below the boiling point of the bleed reducing additive be used, as
long as that temperature will not cause elastomer degradation.
[0517] Materials of the formulas shown have been used to measure
oil bleed. Percent oil bleed was measured by obtaining the combined
weight of three disk shaped samples of the material, each sample
having a diameter of about 3 cm and a thickness of about 6.5 mm.
Two four inch square pieces of 20# bond paper were then weighed
individually. The three sample disks were placed on the paper
(which has high capillary or wicking action), and the other piece
of paper was placed on top of the sample. The material and paper
were then placed in a plastic bag and pressure sandwiched between
two flat steel plates, each weighting 2285 g. Next, the material
samples, paper and steel plates were heated to 110 degrees F. for 4
hours. Alternatively, two pieces of 12.5 cm diameter qualitative
filter paper having a medium filter speed and an ash content of
0.15%, such as that sold under the trade name DOBLE RINGS 102 from
Xinhua Paper Mill may be used in place of the two four inch square
pieces of 20# bond paper. The following are example
formulations.
Example 74
[0518]
71 Component Generic Class weight percent SEPS (4077) copolymer
11.2 Mineral oil (LP-150) plasticizer 87.4 FC-10 Fluorochemical
alcohol bleed reducer 0.3 Saturn Yellow pigment 1.2
Example 75
[0519]
72 Component Generic Class weight percent SEPS (4055) copolymer
12.3 Mineral oil (LP-150) plasticizer 86.1 Zonyl FSN-100 bleed
reducer 0.4 Horizon blue pigment 1.2
Example 76
[0520]
73 Component Generic Class weight percent SEPS (4055) copolymer
12.3 Mineral oil (LP-150) plasticizer 86.1 FC-10 Fluorochemical
alcohol bleed reducer 0.4 Saturn Yellow pigment 1.2
Example 77
[0521]
74 Component Generic Class weight percent SEPS (4077) copolymer
17.9 Mineral oil (LP-150) plasticizer 81.6 FC-10 Fluorochemical
alcohol bleed reducer 0.5 Neon red pigment 0.9
Example 78
[0522]
75 Component Generic Class weight percent SEPS (4055) copolymer
12.3 Mineral oil (LP-150) plasticizer 86.1 Zonyl TA-N bleed reducer
0.4 Blaze Orange pigment 1.2
Example 79
[0523]
76 Component Generic Class weight percent SEPS (4055) copolymer
14.1 Mineral oil (LP-150) plasticizer 84.7 FC-10 Fluorochemical
alcohol bleed reducer 0.3 Magenta pigment 0.9
Example 80
[0524]
77 Component Generic Class weight percent SEPS (4055) copolymer
13.4 Mineral oil (LP-150) plasticizer 80.2 Krator G 1701 processing
additive 0.3 Irganox 1010 antioxidant 0.2 Irgafos 168 antioxidant
0.2 Dynamar PPA 791 bleed reducer 5.3 Magenta pigment 0.4
[0525] Examples 74-80 exhibited little or no oil bleed when tested
by the above method. The material of Example 80 lost only 0.009
percent of its weight during bleed testing. A tackless formulation
of the gelatinous elastomer may also me made according to the
formula of Example 81 and variations thereof.
Example 81
[0526]
78 Component Generic Class weight percent SEPS (4055) copolymer
24.567 Mineral oil (LP-200) plasticizer 73.701 Irganox 1076
antioxidant 0.246 Irgafos 168 antioxidant 0.246 KENEMIDE E ULTRA
grape seed oil -detackifier 0.246 Horizon Blue pigment 0.995
[0527] Grape seed oil or other oils and materials may be used as a
slip agent or detackifier to produce an elastomer with a non-tacky
exterior.
Example 82
[0528]
79 Component Generic Class weight percent SEPS (4055) copolymer
16.50 Mineral oil (LP-150) plasticizer 82.51 Irganox 17E
antioxidant 0.41 Zonyl BE-H detackifier 0.17 Colorant color
0.41
[0529] Example 83 below is a example formulation for making
cushioning elements that may be used in mattresses.
Example 83
[0530]
80 Component Generic Class weight percent SEPS (4055) copolymer 10
Mineral oil (LP-200) plasticizer 22.5 Irganox 1010 antioxidant 0.03
Irgaphos 168 antioxidant 0.03 Aluminum lake pigment colorant 0.03
Zonyl BA-N fluorochemical alcohol bleed reducer 0.05
[0531] Alternative example embodiments of the gelatinous elastomer
for mattressing include changing the mineral oil weight percent
from 22.5 to between 15 and 70, 15 weight percent being a firmer
formulation and 70 being a softer formulation. The most example gel
will have a durometer of less than about 25 on the Shore A
scale.
[0532] Although the gel formulations referred to above are most
example, there are numerous other example gels. For example,
although they exhibit less desirable characteristics than the
example gel cushioning media, the gel formulations of the following
U.S. Patent Nos. are also useful in the cushions: U.S. Pat. No.
5,334,646, issued in the name of John Y. Chen; U.S. Pat. No.
4,369,'84, issued in the name of John Y. Chen; U.S. Pat. No.
5,262,468, issued in the name of John Y. Chen; U.S. Pat. No.
4,618,213, issued in the mane of John Y. Chen; U.S. Pat. No.
5,336,708, issued in the name of John Y. Chen, each of which is
incorporated by reference in its entirety. Other oil-extended
polystyrene poly(ethylene/butylene)-polystyrene gels can be used
advantageously for the cushions hereof. For example, the GLS
Corporation of Cary, Ill. offers a gel in injection moldable pellet
norm under the designation G-6703 which is made with the
ingredients of the gels mentioned above but with less plasticizing
oil, and has a Shore A hardness of 3. Other example gels which may
be used include PVC plastisol gels, silicone gels, and polyurethane
gels.
[0533] PVC plastisol gels are well known in the art, and are
exemplified by artificial worms and are also cheaper to make than
thicker walled lower durometer cushions. And if the gel is used as
a shoe insert, then the example gels just described will be
superior because the gel will not tend to flow out from under the
foot being cushioned (or other object being cushioned) as it would
grubs used in fishing. A description of a typical PVC plastisol gel
is given in U.S. Pat. No. 5,330,249 issued in the name of Weber et
al. on Jul. 19, 1994, which is hereby incorporated by reference.
PVC plastisol gels are not the most example because their strength
is not as high for a given gel rigidity as the example gel media or
even the gels of the Chen patents, but they are acceptable for
use.
[0534] Silicone gels are also well known in the art, and are
available from many sources including GE Silicones and Dow Corning.
From a performance standpoint, silicone gels are excellent for use
herein. However, the cost of silicone gels is many times higher
than that of the most example gels.
[0535] Also in the most example gels, the ratio of plasticizer such
as oil to triblock copolymer is 3:1 or less (such as 2.5:1; 2.0:1;
1.5:1; and 1.0:1.0). At these ratios, the gel is not stirable
during the melting process and is not castable when melted. Thus
this gel is not suitable for typical prior art manufacturing such
as that proposed in the John Y. Chen patents. However, the inventor
has found that these low ratios of plasticizer to copolymer have
very high strength, superior shape retention, lower tack, and lower
bleed-out properties than the prior art. They also have a higher
durometer than the prior art. Cushioning devices, such as hollow
column gel cushions, can be made much lighter if the walls are thin
and of a high durometer. Such cushions with prior art gels such as
those of John Y. Chen. Finally, gels of these formulations exhibit
much better processability through screws, such as the compounding
screws of extruders and injection molding machines. The prior art
Chen gels do not feed through screws well because they are too
slippery in the pre-mix state and are not driven well by screws
because their viscosity is too low. The gels have a higher
viscosity and perform much better when pushed by a screw such as in
an injection molding machine or in an extruder.
[0536] Polyurethane gels are also well known in the art, and are
available from a number of companies including Bayer
Aktiengesellschaft in Europe. For reference, the reader is directed
to U.S. Pat. No. 5,362,834 issued in the name of Schapel et al. on
Nov. 8, 1994, which is hereby incorporated by reference, for more
information concerning polyurethane gels. Like silicone gels,
polyurethane gels are excellent from a performance standpoint, but
are many times more expensive than the most example gels.
[0537] Foam rubber and polyurethane foams may also be useful as
cushioning media in the cushioning elements, so long as they
exhibit gel-like buckling behavior. Preferably, in order to exhibit
desired buckling and elastomeric or visco-elastomeric gel-like
behavior, column walls formed from polyurethane foams and foam
rubbers are very thin. Alternatively, thicker column walls formed
from polyurethane foams and foam rubbers may also exhibit the
desired buckling and gel-like characteristics with appropriate
column shapes and column pattern configurations. Foam rubbers and
polyurethane foams are useful in the cushioning element if columns
occupy about one-half or more of the cushion volume. Cushion volume
is defined by the top and bottom surfaces and the perimeter of the
cushion.
[0538] Method for Making the Cushions
[0539] There are several ways in which the cushion can be
manufactured.
[0540] Injection Molding
[0541] The cushions can be injection molded by standard injection
molding techniques. For example, a cavity mold is created with
cores inside the cavity. The gel ingredients are heated while
stirring, which turns the gel into a liquid. The liquid is injected
into the cavity and flows around the cores. The material is allowed
to cool, which causes it to solidify. When the mold is parted, the
cores pull out of the solidified gel and leave the hollow columns.
The cushion is removed from the cavity, the mold is closed, and
liquid is injected to form the next cushion, this process being
repeated to manufacture the desired quantity of cushioning
elements. This results in very inexpensive cushioning elements
because the example gel is inexpensive and the manufacturing
process is quick and requires very little labor.
[0542] Referring to FIG. 4, an example mold in use is depicted. The
mold assembly 401 has a first mold half 401 and a second mold half
404. The second mold half 404 has a cavity 408 and a base plate 405
at the bottom of the cavity 408. It also has side walls 414 and
415. The first mold half 402 has a core mounting plate 409 and a
plurality of cores 403 mounted on it in any desired spacing, and
arrangement. The cores 403 may be of any desired shape, such as
triangular, square, pentagonal, n-sided (where n is any integer),
round, oval or of any other configuration in cross section in order
to yield a molded cushioning element 406 of the desired
configuration. The cores 4,03 could also be tapered from a more
narrow dimension (reference numeral 410) at their end distal from
the core mounting plate 409 to a wider dimension (reference numeral
411) at their end proximal the core mounting plate. This would
create a tapered column or tapered column walls so that the radial
measurement of a column orthogonal to its longitudinal axis would
be different at two selected different points on the longitudinal
axis.
[0543] Alternatively, the cores 403 could be tapered from 410 to
411, stepped from 410 to 411 or configured otherwise to create a
column of desired shape. Use of the hexagonal cores 403 depicted
yields a cushioning element 406 with cushioning media 412 molded so
that the column walls 413 form the hollow columns 407 in a
hexagonal configuration.
[0544] When the first mold half 402 and second mold half 404 are
brought together, core distal ends 410 abut the second mold half
base plate 405. This prevents liquid cushioning media from flowing
between the base plate 405 and the core distal ends 410 in order to
achieve a cushioning element 406 which has hollow columns through
which air can circulate. If the core distal ends 410 did not reach
all the way to the base plate 408, then the columns 407 would be
open at one end and closed at the other.
[0545] FIG. 5 depicts an alternative mold configuration. The mold
assembly 501 includes first mold half 502 that includes a first
core mounting plate 509 onto which a plurality of cores 503 are
mounted in a desired configuration. The cores 503 each have a core
proximal end proximal to the core mounting plate 509 and a core
distal end 511 distal to the core mounting plate 509. The mold
assembly 501 also includes a mold second half 504 which has a core
mounting plate 505, side walls 512, and cores 508 each having a
core proximal end 513 proximal to the core mounting plate 505 and a
core distal end 514 distal to the core mounting plate. The second
core half 504 also has a cavity 514 in which its cores 508 are
found. The mold assembly 501 may be designed so that when the two
mold halves are brought together the core distal ends abut the
surface of their opposing core mounting plates. This produces a
cushioning element 506 with hollow columns 507 that are open from
one end to the other in order to maximize air circulation through
the columns 507 and yieldability of the cushioning element 506.
Alternatively, the mold assembly 501 may be designed so that the
core distal ends do not contact the core mounting plates. This will
result in a cushion having a cross sectional appearance like that
depicted in FIG. 6, where the columns are shorter in length than
the thickness of the cushioning element, so the columns are closed
at one end.
[0546] In the prior art, such the John Y. Chen gel patents and in
U.S. Pat. No. 5,618,882, the example method for manufacturing gel
articles was casting, and the example method for making the gel was
melt blending. These prior art manufacturing methods are slow,
expensive, messy and inefficient.
[0547] The applicant has learned how to manufacture gel articles
using gels of the example formulations and other formulations by
filling a hollow cavity in a mold with the gel. A mold with a
hollow cavity of appropriate shape for the article to be made is
first obtained. Then a quantity of gelatinous elastomer or
viscoelastomer is obtained, or the ingredients for making it are
obtained. Then the gelatinous elastomer or viscoelastomer or the
ingredients are fed into a compounding screw (such as a single
screw or a twin screw) of an appropriate machine such as an
injection molding machine or an extruder. Then the screw moves the
gel along its length under temperature and pressure. Then the screw
moves the gel into a cavity of a mold in order to fill the cavity
of the mold and create a molded gel article. With this
manufacturing method, the materials of the gel are exposed to heat
for a much shorter time than prior art manufacturing methods,
resulting in less elastomer degradation. The materials of the gel
are also exposed to heat for a shorter period of time. And because
the gel can be forced into the mold under pressure rather than
relying on gravity flow for casting, articles of a wide variety of
shapes can be made and articles can be made with the use of little
plasticizer, resulting in much stronger gels. Alternatively,
instead of injecting the gel material into the mold, it can be
allowed to flow into the mold under its own weight.
[0548] Extrusion
[0549] The cushioning elements may also be manufactured by typical
extrusion processes. If extrusion is used, hot liquid gel is forced
through an extrusion die. The die has metal rods situated to
obstruct the path of the gel in some locations so that the gel is
forced through the die in a pattern resembling the desired shape of
the finished cushioning element. Thus the die, having an aperture,
an aperture periphery, and forming rods within the aperture has an
appearance similar to that of the desired cushioning element except
that the portions of the die that are solid will be represented by
empty air in the finished cushion, and the portions of the die in
the aperture that are unobstructed will represent gel in the
finished cushioning element. Thus the rods of the die should be of
the shape and size that the desired cushioning element is intended
to be; the spacing of the rods should approximate the spacing of
the columns that is desired in the finished cushioning element; and
the shape and size of the aperture periphery should approximate the
shape and size of the periphery of the desired cushioning
element.
[0550] When gel is forced through the die, the liquid gel is cooled
during its traverse through the die, causing it to solidify as it
leaves the die. The gel is then cut at desired length intervals to
form cushioning elements. Of course, cushioning elements so formed
have hollow columns throughout their length, although the ends of
the columns could be sealed as mentioned elsewhere herein. It is
not expected, however, that extrusion is a practical method for
manufacturing cushions with columns that vary in dimension along
their length. The extruded cushioning element is very inexpensive
because the both the cushioning media (i.e. the example gel) is
inexpensive and the manufacturing process is highly automated so
that labor requirements are very low.
[0551] Alternatively, a single tube may be extruded, then cut to a
length that will form the appropriate cushion thickness. The tubes
are then bonded together to form a cushioning element. Referring to
FIG. 41, a example embodiment of a cushion 4101 which is made from
bonded tubes 4102a, 4102b, 4102c, etc. is shown. Each tube includes
a hollow column 4103 formed by a column wall 4104. Preferably,
column wall 4104 is made from a gel cushioning medium 4105, such as
the example elastomeric or visco-elastomeric materials for use in
the cushions.
[0552] FIG. 42 illustrates an example of a example method for
bonding two tubes 4102a and 4102b together. Heating cores 4201 and
4203, which preferably include a heating edge 4202 and 4204,
respectively, are positioned in tubes 4102a and 4102b within
corners 4110a and 4110b, respectively, such that edges 4202 and
4204 abut the inner surface of the corners. Preferably, cores 4201
and 4203 hold the outer surface of corners 4110a and 4110b against
one another.
[0553] Preferably, securing cores 4205 and 4206 are positioned in
each of the two inner corners formed by tubes 4102a and 4102b to
secure corners 4110a and 4110b from sliding side-to-side in
relation to one another. Preferably, heating edges 4202 and 4204
are heated to a temperature sufficient to melt cushioning medium
4105, but not to a temperature which would burn the material. As
heating edges 4202 and 4204 are heated to a desirable temperature,
the cushioning medium located in corners 4110a and 4110b melts.
Preferably, heating edges 4202 and 4204 remain heated until all of
the material located at corners 4110a and 4110b becomes molten and
fuses tubes 4102a and 4102b together. Heating edges 4202 and 4204
and corners 4110a and 4110b are then cooled. Preferably, heating
edges 4202 and 4204 are each covered with a non stick surface 4207
and 4208, respectively. Similarly, securing cores 4205 and 4206
also have non-stick surfaces 4211 and 4212. The non-stick surfaces
prevent the securing cores 4205 and 4206 and heating edges 4202 and
4204 of heating cores 4201 and 4203 from sticking to the cushioning
medium located at corners 4110a and 4110b as the medium becomes
molten. A example non-stick surface is Teflon paper. Cores 4201,
4203, 4205 and 4206 are then removed from tubes 4102a and
4102b.
[0554] In the example extrusion method, the elastomer gel is
pre-compounded at a temperature of about 470 degrees Fahrenheit.
Then the gel is run through an extrusion die at a example
temperature of about 425 degrees Fahrenheit. The pressure in the
extrusion die may be from 200 to 4001) pounds per square; inch,
depending on the gel being extruded and the die dimensions and
characteristics. The formulation of the gel will affect desired
temperature. The part may be extruded from a die into water to aid
in cooling and solidifying the gel. The gel may be extruded upwards
through a die and into water of necessary to maintain the shape of
the extruded part.
[0555] The same advantages and techniques for using a screw to
compound or simply melt gel material and force it into a mold from
an injection molding machine can be applied to an extruder, using
the extruder screw to compound the gelatinous material and force it
through a die. Thus larger, more complex and stronger parts can be
made when the extrusion method is used than if prior art casting is
used.
[0556] Casting
[0557] Another manufacturing process by which the cushioning
element can be made is by generally known casting technology. In
order to cast the cushioning element, hot liquid gel (or other
cushioning media) is poured into an open cavity, and an assembly of
metal rods is pushed into the liquid. The rods will form the
columns of the finished product. The liquid flows between the metal
rods, cools and solidifies. The metal rods are then removed,
leaving; the hollow portions of the columns, and the cushion is
removed from the cavity. A vibrator may be used to vibrate the
cavity to facilitate the flow of the liquid between the rods if
needed.
[0558] With reference to FIG. 42, in an alternative casting
process, about half of the column forming rods have a plurality of
protrusions extending therefrom. Preferably, each of the rods which
are adjacent to a rod which has protrusions extending therefrom do
not include protrusions therefrom. The example protrusions extend
toward each of the adjacent rods and substantially across the
distance between the adjacent rods. As cushioning medium is cast
using this process, the rods with protrusions preferably create
fenestrations in the column wall which surrounds the column created
thereby, each of the fenestrations preferably passing substantially
through the column wall to an adjacent column. FIG. 42 shows one
example configuration of fenestrations 4200, having a circular
shape. Other shapes such as diamonds, squares, triangles, or others
are also useful as fenestrations. After the cushioning medium has
solidified, the rods which lack protrusions are preferably removed
from the cushioning element first. The rods with protrusions are
then removed from the cushioning medium, which, due to its softness
and elastomeric or visco-elastomeric properties, gives easily
without tearing or breaking as the rods are removed.
[0559] Casting is a more labor intensive manufacturing method than
injection molding or extrusion, but the tooling is generally less
expensive, especially for large cushions. This is the example
method of making very large cushions, such as king-size bed
mattresses, since the size of such cushions is greater than that
which can be manufactured using injection molding or extrusion
methods.
[0560] Two Step Manufacturing Process
[0561] In many instances it is advantage to prepare the gelatinous
material in advance and manufacture a product from it at a later
date. The inventor has implemented a process for doing this that
has very beneficial qualities for the manufacture of gel
products.
[0562] The first step is to manufacture the gelatinous elastomer.
This is done by gathering appropriate ingredients, as described in
detail above, and appropriate equipment for compounding the
elastomer. While melt blending and solvent blending are possible,
it is much example to use either a single screw or a twin screw
compounder such as those found on extruders and injection molding
machines. The ingredients for the gel are fed into the screw at one
end, and as the screw moves the ingredients along its length under
pressure and temperature, compounding of the ingredients takes
place (such as association of the plasticizer with the elastomer
molecules and association of the bleed reducing additive with both
the plasticizer and the elastomer molecules). As the compounded gel
exits the screw, it may then be cut or chopped into small pieces or
pellets.
[0563] The pellets can be stored (such as in bags or barrels),
transported and later used. In the later use, the second step is
performed. I it, the pellets are melted in order to injection mold,
extrude, cast or spray a final product with the gel. It is example
that the pellets will be melted again under pressure in a screw
such as that found on an injection molding machine or extruder.
[0564] There are distinct advantages to this two step process.
First, in the first process step the lower molecular weight
fractions (volatiles) of the plasticizer (such as mineral oil) are
boiled off. Thus, in the second step there is no boiling of the
plasticizer and voids in the manufactured part are reduced. Quality
of the finished product and strength of the finished product are
thus greatly enhanced.
[0565] Another advantage is that some screws have difficulty
grabbing and transporting the ingredients of the gel because they
are slippery and coated with oil, but the screw can easily grab and
push the preformed pellets. Thus, the use of pre-formed pellets
allows the use of a much shorter screw and shorter processing times
and shorter exposure to high temperatures. Although the example
method for this embodiment includes running the gel through the
screw twice, any compounding method may be used twice on the same
gel in order to achieve good results. It desirable, the pellets can
be extruded underwater or fall into water for instant cooling, or
spread out on a stationary or moving surface for air cooling.
[0566] Other Cushioning Devices
Cushions Comprising End-Supported Free-Standing Buckling Elastic
Members, and Methods for Manufacturing the Same
[0567] As used herein, cushions are defined as pads of any shape
which equalize or redistribute pressure over the surface of an item
which bears on the pad, which soften the surface on which the load
from the item bears, which absorb or attenuate vibration and/or
shock to protect the item, and/or which provide: a resilient action
to separate the item from the movements of its surroundings. More
specifically, this embodiment is for a cushion which achieves these
cushioning features through the buckling action of end-supported
free-standing buckling elastic members, and does so in a manner
which provides advantages over prior art cushions.
[0568] The inventor intends to obtain the advantages of buckling
column performance with foam, which is lightweight and inexpensive
and bonds readily to other materials. Unfortunately, sculpted foam
compresses an a single unit rather than buckling under point load.
The embodiment described below achieves advantages of gelatinous
buckling columns but with light weight and low cost.
[0569] This embodiment is a cushion comprising one or more
free-standing buckling members which are supported at or near the
ends. These buckling members are configured to sustain a given
level of compression loading from the cushioned item resulting in
compression deformation without buckling, and then if that given
level of compression loading is exceed, to buckle and undergo
further deformation with less than a linearly proportional increase
in loading. A rail is supported at the ends in that it is tied into
an overall supporting structure at each end of the buckling portion
of the member. The rail is allowed to continue beyond the buckling
portion. Free-standing indicates that a buckling portion of the
member is not integrally connected to another member or to another
support structure other than at or near the ends, thus allowing
free buckling. One or more portions of the member can be connected
non-freestanding, so long as at least one buckling portion is free
standing. The buckling members can be solid or hollow.
[0570] The degrees of buckling freedom of the buckling members of
the cushion can be one or more. For example, a round column can
buckle in any lateral direction, so it has unlimited degrees of
freedom. As a second example, a column of square cross-sectional
shape buckles more easily in two orthogonal directions than in
other directions, so it effectively has two degrees of freedom. As
a third example, a rail which is 1 inch thick, 5 inches tall, and
30 inches long and attached to a support at each end of the 30-inch
length is most likely to buckle in a direction transverse to the
length; thus it effectively has one degree of freedom. This
embodiment is not limited to any particular member shape or
configuration so long as it meets the criteria set forth above.
[0571] Neither is this embodiment limited to the specific material
of construction. Any material which is elastic or visco-elastic in
nature, meaning that when load is removed it will quickly or at
least eventually spring back to about the original shape and size,
and which is durable enough to meet the operating conditions of the
cushion, will work.
[0572] Steel meets this criteria, and is particularly useful in the
form of coil springs. Compressible coil springs can form the
buckling members. The spring should be sized (wire diameter, wrap
diameter, wrap density, etc.) so that it's overall length-to
diameter ratio results in instability when loaded at less than or
equal to the maximum desired localized cushioning load, and so that
the compression of the spring in the pre-buckle loading is
acceptable for the given cushioning requirement. For example, in a
mattress or any other cushion for the human body, it is desirable
that the cushion be able to support a pressure load of at least 20
mm of Hg, but never over 32 mm of Hg (the capillary shut-off
pressure in at-risk individuals). The spring should then be
designed so that when 20 mm of Hg is applied over the area of the
cushion supported by that spring, the spring compresses without
buckling, but when 25 mm of Hg are applied over the same area, the
spring buckles. The ends of the free-standing coil springs can be
supported by being inter-laced in a network of criss-crossing
lateral springs, much as is done in spring units of prior art
mattresses. The difference between the springs of my cushion and
the prior-art mattress spring units is that prior art springs are
designed to be stable against buckling and only compress when
loaded, whereas the springs are unstable and will buckle if
overloaded.
[0573] Elastomers such as rubbers, oil gels, silicones,
polyurethanes, plastisols and the like will also work. Unlike the
gel hollow-column shared-wall cushions described above, however,
the buckling members hereof must be free standing.
[0574] Flexible open-cell polyethylene-based polyurethane foams,
such as is widely and commonly used in the furniture and mattress
industry, work well. One of the characteristics is that a foam
cushion with buckling members is considerably softer overall than a
cushion of the same dimension made of solid foam. Thus, a much
stiffer, denser foam can be used with the same overall cushion
durometer, and since denser foams are much stronger and more
durable than lighter foams, the overall durability of the cushion
can be greater than the `solid` foam cushion being replaced with
the cushion. A unique process for fabricating foam cushions with
buckling members which has low labor requirements and minimal
waste, thus keeping cost to a minimum is disclosed. This process,
along with the embodiment in two types of foam cushions, are
illustrated by the following examples. These examples are by way of
illustration, and should not be construed as limiting.
[0575] The first example is as follows. A bun (such as 30" high,
80" long, 60" wide) of high resiliency polyether-based polyurethane
flexible foam is purchased from a foam manufacturer, with an ILD of
50 and a density of 2.8 pounds per cubic foot (considered very
durable). A solid foam mattress with an ILD of 50 would be much too
firm for the typical consumer. However, the cushion of this example
is much softer than a `solid` slab of 50 ILD foam. FIG. 43 shows a
cutting pattern 4301. Each dashed line 4302 shows a cut all the way
through the width of the bun (i.e., into the paper). These cuts are
made by a CNC reciprocal saw such as is made by Baumer USA and is
well known in the art. The bun is then turned 90 degrees and cut in
a similar fashion as shown in FIG. 44 using its cutting pattern
4401. When the bun is disassembled as shown in FIG. 45, and the
thin disconnected sections are removed, the resulting foam pieces
4501, 4502, 4503, 4504, 4505 and 4506 are bonded together with any
of several common foam adhesives to result in the mattress core
4601 of FIG. 46. FIG. 47 depicts foam side support pieces 4701
having been inserted into receptacles 4702 in all four sides of the
foam unit 4703. A cover can then be applied by methods well known
in the art. The mattress core has one-piece foam skins which are
integral with and which support the many square cross section free
standing columns of square cross section within the core.
[0576] FIG. 48 shows half of the mattress core 4801 before bonding
to the other half, illustrating the individual square half-columns.
The half-columns become full columns when the piece is bonded to a
like piece of opposite orientation. This mattress cushion is
capable of high local deformations due to the buckling of the
square columns within the cushion. A person lying on his side on
this mattress has the feeling that there is no significant pressure
on his hips or shoulders, but that his torso is receiving
sufficient pressure that sagging of the back does not occur.
[0577] The second example is as follows. A bun (such as 30" high,
80" long, 60" wide) of high resiliency polyether-based polyurethane
flexible foam is purchased from a foam manufacturer, with an ILD of
50 and a density of 2.8 pounds per cubic foot (considered very
durable). FIG. 51 shows a example cutting pattern 5101. Each dashed
line shows a cut all the way through the width (into the paper).
These cuts are made by a CNC reciprocal saw such as is made by
Baumer USA and is well known in the art. This is a simpler pattern,
and quicker to cut, than the illustration of the previous example.
As a further contrast to the previous example, this bun is cut from
only one direction rather than turned 90 degrees and cut a second
time. When the bun is disassembled as shown in FIG. 52, very little
is discarded. The resulting foam pieces 5201 5212 are bonded
together as shown in FIGS. 52 and 53 with rails 5201 and 5202 being
bonded with any of several common foam adhesives to result in the
mattress core of the previous example. A cover is then applied. The
mattress core has one-piece foam skins which are integral with and
which support the foam free-standing rectangular rail within the
core. These are the type of rails described above as effectively
having one degree of freedom. While this may reduce the overall
effectiveness of the cushion compared to buckling members with
multiple degrees of freedom, it is still effective and results in a
less expensive mattress to produce because cutting time is reduced
and waste is minimized.
[0578] This mattress cushion is capable of high local deformations
due to the buckling of the rectangular rails within the cushion. A
person lying on his side on this mattress has the feeling that
there is no significant pressure on his hips or shoulders, but that
his torso is receiving sufficient pressure that sagging of the back
does not occur. FIG. 54 shows how the rail members 5402 buckle 5401
under the more protruding parts of the body 5401.
[0579] Buckling members, because they do not support load
effectively, also do not transmit vibration, shock, or movement
effectively. Thus the cushions are effective in cushions which have
such requirements. Further, the cushions are softer than cushions
made from the same types of materials without buckling columns. In
part, this is because material is missing around my free-standing
buckling members. But more significantly, the cushions are able to
locally deform without dragging down the surrounding material to
the extent that `solid` cushions do.
[0580] The cushions hereof, as illustrated but not limited to the
examples above, create a cushion different from and superior to the
prior art in several ways. The cushions are very effective at
pressure redistribution and equalization because the buckling
member are incapable of taking more than their area share of the
load, and surrounding members pick up the load that is `refused` by
the buckled members. The cushions are effective at
absorption/attenuation of vibration, shock, and movement because
buckled columns do not transmit these as well as `solid` material
or structurally sound members. The cushions are very soft because
they allow local deformation with less dragging down of the
surrounding material. Unlike elastomeric compression cushions, my
cushions do push back in linear proportion to the deformation of
the cushion; thus pressure hot-spots are minimized, and support is
even (e.g., back doesn't sag on a mattress). Unlike bladderized
flowable-medium cushions, the cushions cannot leak, are very light
weight, are low cost, have less tendency to crush down over time
(because higher density foams are usable), and has no hammocking
and therefore none of the associated problems. Unlike cushions
comprising hollow gel columns with shared walls, these cushions are
very light weight, less expensive to produce, and bond well to
other cushion components (e.g., a mattress cover or furniture
cushion cover).
Methods and Apparatuses for Providing Border Stiffness Around a
Cushion
[0581] This embodiment is in the area of methods of cushion
borders. More specifically, this embodiment includes methods and
apparatuses for advantageously and economically stiffening the
edges of hollow-columned low-durometer elastomer cushions (such as
described above) while providing lateral tension on the elastomer
structure.
[0582] Gelatinous hollow-columned low-durometer elastomer cushions
such as those described above make very effective cushions by
equalizing pressure across an uneven person or object.
Unfortunately, these cushions are not very laterally stable
especially when made with thin walled hollow columns. They are more
stable when the column walls are at least one third of the column
width, but the weight and cost are much too high for most practical
applications. When a more practical thin-wall hollow column
configuration is used, the cushion easily collapses sideways. A
need thus exists for a border which will keep the hollow column
from collapsing laterally. Practical experiments with hollow column
have also shown that if a small degree of lateral bi-axial tension
is applied to the hollow column (in other words, it is kept a bit
stretched out so it is tight), it is more effective in providing
good support and pressure equalization.
[0583] Another problem with thin-wall hollow column cushions,
particularly in mattress applications, is that when the columns
collapse, only a small portion of the original height remains.
Sitting on the edge of a mattress thus leaves the sitter feeling
unsupported and perhaps unstable. A need exists for a border for
hollow column cushions including but not limited to mattresses
which will be more substantial for needs including but not limited
to sitting.
[0584] This discussion will focus on mattresses as typical, but
this applies to all hollow-column cushions. The mattress industry
has developed many borders. For example, a classic waterbed has
wooden sides. A "foundation" waterbed, which appears more like a
traditional mattress, has a very stiff flexible open-cell
polyurethane border several inches wide around the entire perimeter
of the water bladder area, inside the cover. It must be
stiff--unacceptably stiff--because it is not attached mechanically
to the inner water bladder(s), and even if it was they would
provide little support. Spring mattresses are made of coil springs
joined at their tops by smaller diameter lateral coil springs, and
do not provide sufficient edge support by themselves. Manufacturers
of spring mattresses thus use well known border systems which
included edge wires and edge clips and other known devices to
stiffen and strengthen the edges of the mattress. Manufacturers of
latex foam rubber mattresses often put a border of polyurethane
foam around the perimeter of the latex core before applying the
cover, in a manner known as a "racetrack". The foam is stiffer than
the floppy latex, but not so stiff as to be uncomfortable as with
the foundation waterbed mattresses.
[0585] An open-cell flexible foam border would be very acceptable
on the perimeter of a hollow column mattress core within a mattress
cover. Unfortunately, unlike with a latex foam rubber core, the
foam cannot be glued to the hollow column gel because the oil
component of the gel prevents reliable bonding with known practical
adhesives. It would not be desirable to use a very stiff foam as
with the foundation waterbed mattresses, because they are
uncomfortable. Thus a method is needed to economically and reliably
attach a foam border to a hollow column gel cushion perimeter. A
further need exists for a method to provide sufficient stiffness to
the border to pre-tension the hollow column laterally without
ruining the sitting feel of the border.
[0586] This embodiment is to encapsulate one or more outer cell
walls of a hollow-column buckling cushion within a border material
or group of materials so as to physically interlock the hollow
column gel and the border. Added features are (1) means to prevent
the border so formed from being taller than the hollow column gel
by removing a portion of one or more exterior cell walls in the
hollow column gel to allow the border material(s) to be continuous
across what would otherwise be solid elastomer wall and (2) to
reinforce the border with another member which would allow lateral
pre-tensioning of the hollow column gel without putting so much
lateral load on the border material(s) as to bend the border beyond
desirable limits. This is best illustrated by means of examples,
which are not to be interpreted as limiting the above description
in any way.
[0587] FIG. 55 shows a 6" tall hollow column gel mattress core
5501. The mattress core 5501 includes foam pieces 5502 stuffed into
each outer perimeter cell of the hollow column gel. They are
adhesively bonded to an exterior piece of foam through holes 5503
punched in the hollow column gel outer walls. The inner and outer
foam pieces are optionally further joined by a cap top and bottom
5504 and 5504, in this case made from foam felt. A fiberglass rod
5506 is inserted through holes punched in the interior walls of the
hollow column gel and through the foam pieces stuffed into the
outer cells. This rod does not overly interfere with the sitting
comfort of the cushion because it is buried so deeply in the soft
foam of the border. The rod is very stiff and thus allows lateral
pre-tensioning of the hollow column gel. The rod is joined to other
rods around the periphery by lugs at the four corners of the hollow
column gel.
[0588] Another example is depicted in FIG. 56. That figure shows
the configuration of FIG. 55 but with an additional layer of softer
"pillow-top" style hollow column gel atop the stiffened 154 hollow
column gel mattress core. The encapsulation of the hollow column
gel sides within the foam border 5602 involves several perimeter
rows of cells, and keeps the hollow column gel pillow-top 5601
securely in place so that it cannot collapse laterally.
[0589] FIG. 57 depicts a configuration similar to that of FIG. 56
but with two "pillow-top" hollow column gel layers 5701 and 5702
encapsulated within the foam border.
[0590] FIG. 58 shows a border configuration made from two pieces of
foam per side of the mattress core. A hollow column gel cushioning
element 5801 is provided with fiberglass rods 5802 as discussed. A
first foam border layer 5803 and a second foam border layer 5804
are provided for border stiffness. This is anticipated to require
less labor input than the individual cell foam pieces of the prior
examples because there are less pieces to handle. This requires
that the pieces be continuous across the first hollow column gel
cell wall. The cell walls were thus beveled 5805 as shown to allow
this continuity.
[0591] FIG. 59 shows the configuration of the previous example but
with an additional layer of softer "pillow-top" style hollow column
gel 5901 atop the mattress core 5801. The encapsulation of the core
5801 sides within the foam border 5903 and 5804 keeps the pillow
top layer 5901 securely in place so that it cannot collapse
laterally, and does not increase the number of foam pieces
needed.
[0592] FIG. 60 shows a fixture 6000 which assists in installing the
foam pieces of the previous two examples. Without such a fixture,
it is difficult to get the adhesive-coated foam uniformly into the
outer row of hollow column gel cells. FIGS. 60a and 60b show the
fixture 6000 with the foam 6001 inserted and not inserted
respectively. FIGS. 7, 8, and 9 show the method used in conjunction
with this fixture. FIG. 61 depicts the fixture 6000 in use with the
foam 6001 being inserted into the fixture so that the slit foam is
inserted into the hollow column gel 6003 cells. The foam and the
hollow column gel should be glued for assembly. When the fixture is
removed, the foam will expand to fill the hollow columns of the
hollow column gel, keeping the pieces assembled until the glue can
dry.
[0593] FIG. 62 shows a method for use in conjunction with the foam
border hereof to allow lateral pre-tensioning of the hollow column
gel without a fiberglass rod. A layer of foam which spans the
entire hollow column gel mattress core surface is bonded to the
border form on the bottom of the mattress core, and optionally on
the top as well. Thus, there is a hollow column gel core 6201 with
a layer of foam on top and bottom 6205a and 6205b, and a layer of
foam 6202 and 6203 around the outer periphery of the hollow column
gel. This ensures that the user will not feel anything hard as may
happen with the fiberglass rod. When the weight of the mattress
core descends on this foam layer, it will gently force it to be
straight, keeping the foam border, which is bonded to it, from
bending in from the lateral tension on the hollow column gel. The
foam layer(s) have the added advantage of making `bottoming out`
through the hollow column gel more comfortable experience when, for
example, kneeling on the bed.
[0594] FIG. 63 shows a hollow column gel `pillow-top` 6301 that can
be laid over any mattress regardless of construction. It uses a
hollow column gel core 6302 and a foam border 6303 that consists of
pieces of foam stuffed into the outer two rows of cells of the
hollow column gel and bonded to an exterior piece of foam by means
of a bridging member. This border assembly is then glued into a
fabric cover 6304, which is hook-and-loop attached to the mattress
below so that the hollow column gel can be pretensioned.
[0595] FIG. 64 shows a pillow-top of hollow column gel 6401 similar
to that of the previous figure except that it has two layers of
hollow column gel 6402 and 6403 pillow-top material. The devices
are not limited to any particular border material or hollow column
gel material.
[0596] The key features are to encapsulate one or more outer cell
walls of a hollow-column buckling cushion within a border material
or group of materials so as to physically interlock the hollow
column gel and the border. Added features are (1) means to prevent
the border so formed from being taller than the hollow column gel
by removing a portion of one or more exterior cell walls in the
hollow column gel to allow the border material(s) to be continuous
across what would otherwise be solid elastomer wall and (2) to
reinforce the border with another member which would allow lateral
pre-tensioning of the hollow column gel without putting so much
lateral load on the border material(s) as to bend the border beyond
desirable limits. While open-cell flexible polyurethane foam is the
example border material, other materials could be used, including
wood, air bladders, metal, plastic, closed cell foams, latex foams,
rubber, synthetic elastomers in solid or hollow configurations,
etc. Rigid members of any type may be used in place of the example
fiberglass rods, including metal, wood, plastic, etc. Flexible
members of any type may be used in place of the example open-cell
polyurethane foam layer that spans the mattress surface, including
thermoplastic films, elastomer films, rubber sheets, closed cell
elastomeric foam sheets, felt, reticulated foam, etc.
[0597] Rigid, Collapsible Mattress Foundations
[0598] This is in the area of foundations for conventional bed
mattresses and other mattresses of similar construction. More
specifically, this relates to a foundation, for use in supporting a
conventional mattress such as an innerspring or foam mattress,
which collapses to ship in a more compact fashion to save shipping
costs, has exceptional durability and function, and provides a
non-slip mattress interface surface, and for methods of making such
foundations.
[0599] Mattresses and foundations are often bought in sets at
retail furniture stores. The foundation (sometimes called a box
spring) is generally to be set into a steel angle-iron frame or
frame of other materials such as wood. The frame holds the
foundation off the floor. The foundation in turn supports the
mattress, which is usually a separate piece. The mattress's main
function is to provide cushioning in a supportive manner, and
typically contains springs, foam, fiber batting, and the like. The
foundation's main function is to provide support for the relatively
floppy mattress so that the mattress does not sag. Another function
is to lift the mattress to a proper height for egress, ingress, and
sitting.
[0600] Prior art foundations are made in a number of ways.
Designers of foundations have several criteria. First is the
structural stiffness necessary so that the mattress cannot sag
overall nor have local bulk deformation. Second is the creation of
space sufficient to lift the mattress to the proper height;
foundations are often in the 7" to 8" high range. Third is
aesthetics, wherein it is desired that the foundation has
upholstery that matches the cover of the mattress. Fourth is to
meet the first and second, and optionally the third, criteria at
the absolutely lowest costs. This fourth criterion often
compromises the first two or three. Foundations are often made
which have inadequate structural support in the bulk and/or local
sense, or which have fabrics over the top or bottom which rip
easily. Foundations are often made by attaching metal wire
structures to a grid of stapled 1.times.2 lumber, then surrounding
the assembly with a cover which consists of a mattress ticking
around the sides (to match the mattress) and a light gauze-like
fabric on the top/bottom. This gauze-like fabric rips easily and is
the source of frustration for many mattress owners that attempt to
move their foundation from one room or residence to another. The
metal wire structures do not provide a uniform solid surface on
which the mattress can rest, allowing local deformation of the
mattress. To save cost, many mattress manufacturers put in too few
metal wire structures, or structures with wire that is too thin.
Manufacturers of high quality foundations must attach a price tag
that limits the number of customers they will have. Another problem
is that foundations are bulky and non-compressible and it is
expensive to ship them from one place to another. This applies to
over-the-road shipping as well as local delivery truck shipping. In
addition to taking up too much room in an over-the-road semi-truck,
a prior art foundation will not be shipped by such carvers as UPS
because it exceeds their size limits. A mattress foundation which
could be so compact as to ship by UPS, which has a 130-inch limit
on height plus girth, would save shippers and thus consumer a lot
of money, and enable products to become nationally distributed
which are otherwise limited to being regional. Another problem with
the prior art is that the gauze-like fabrics, or even
higher-quality mattress tickings used by high-quality
manufacturers, allow the mattress to slip and slide on the
foundation, causing the need for constant positional adjustment by
the accordingly frustrated end user.
[0601] There thus exists a need for a mattress foundation which
ships in a more compact fashion, has exceptional durability, does
not allow local or bulk deformation on even heavy mattresses,
provides a non-slip mattress interface surface, and achieves all of
this at very low cost. A further need exists for such a mattress
foundation which can be made so compact as to ship via local
delivery truck in one or more packages and does not require
complicated assembly by an end user.
[0602] This embodiment is a mattress foundation comprising a
relatively rigid top and separate or separable sides and/or ends.
The separate/separable sides and/or ends either easily disassemble
from the top or fold into parallel with the top.
[0603] In one example embodiment, which is shown in FIGS. 65 and 66
and which is easily shippable, the foundation is divided into six
segments. Each segment has a 1/4 inch thick plywood top, under
which is stapled a grid of 1.times.2 lumber on approximately
14-inch centers, with the 1.50" dimension of the (nominal)
1.times.2 lumber orthogonal to the plane of the plywood. The
plywood overlaps the grid of 1.times.2's by 1/4 inch. The total
thickness of this "top" is 1.75", so six of them can be stacked and
shipped via UPS even in a king-size foundation, in which the
dimensions of each top would be approximately 37 inches by 26
inches. In a separate container, the frame is shipped as separate
boards in a narrow stack. The frame consists of 1/4 inch thick
plywood slats (seven, in the case of the foundation 6501 of FIG.
65) which are joined by plastic extruded pieces which slip over
slots machined into the slats (well known in the waterbed art as
part of a much different type of foundation used in conjunction
with a wooden waterbed). The center three slats are notched to
allow them to all have their top surfaces at the same level. FIG.
66 shows the six tops all set into the frame 6601. Attaching the
tops to the frame is not necessary, since the angle-iron bed frame
constrains the frame, as does each of the six tops, from distorting
in the plane of the mattress. The mattress weight keeps the tops
from coming up out of the frame, while the 1/4 inch overhang on
each top prevents the top from going down through the frame. Thus
the foundation is constrained in all directions and the tops do not
need to be attached by mechanical means. To move the foundation
from one room or residence to another, one simply lifts out the six
tops, removes the plastic connectors, and moves them independently,
then reassembles them in the new room. All is done without any
tools, and is very simple. The plywood top is continuous, is rigid
and made even more rigid by the 1.times.2 grid, and the bulk
stiffness of the foundation is ensured by the multi-board frame.
The top of the plywood can be sprayed or rolled with a pigmented
solvated rubber-like thermoplastic elastomer, such as any of the
Kraton D elastomers from Shell Chemical mixed with toluene, and the
solvent allowed to evaporate. Alternatively, the elastomer can be
melted and applied in the molten state. The remaining thin layer of
rubber-like material creates a non-slip mattress surface, and the
pigment hides the plywood. The outer slats of the frame can be
covered at the manufacturing stage with upholstery material to
match the mattress, and when combined with the pigmented tops
create a very aesthetically attractive look. The durability of the
foundation is assured by the use of durable construction materials
such as plywood; there are no gauze-like fabrics to be easily
ripped or other non-durable materials. The cost is sufficiently low
to be an attractive feature. The total direct labor and material
cost of a queen-sized foundation is expected to be less than US
$20.00, which is on par with the cheapest gauze-covered foundations
of the prior art. The weight of a queen-size foundation in
accordance with this example embodiment is expected to be less than
50 pounds, on par with other poorer quality foundations.
[0604] Another example embodiment is geared toward shipping in
conventional semi-trucks and local delivery trucks. Retail mattress
sellers generally would find any assembly undesirable, even the
small amount of assembly described in the above easily shippable
embodiment. This alternate example embodiment is illustrated in
FIGS. 67a-e. A 1/4 inch thick plywood top which spans the entire
mattress foundation is used, under which is stapled a grid of
1.times.2 lumber on approximately 14-inch centers, with the 1.50"
dimension of the (nominal) 1.times.2 lumber orthogonal to the plane
of the plywood. The plywood is flush with the edge of the grid of
1.times.2's. {fraction (1/4)} inch thick plywood ends and sides are
hinged to the top and fold in as shown in the previous figures. The
overall assembly is only 2.3 inches thick when folded, so it ships
in less than 1/3 the space of a prior art 7-inch thick foundation.
FIG. 67e shows the foundations of this example embodiment stacked
compactly for shipment. The retailer will drive the still compact
foundation to the customer's home, unfold the sides and ends in a
simple motion, and attach the sides and ends to each other at the
four corners. This attachment involves only the lining up of the
corners and the guiding in of a pre-installed attachment, such as a
barbed male-in-female attachment which does not come out once
installed. Instructions for fabricating this example embodiment are
as follows:
[0605] 1. Cut all plywood, 1.times.2 lumber, fabric, foam, and
galvanized strips to size.
[0606] 2. Staple (or nail) the width-wise continuous slats flush
all around with the edges of the top plywood. Make sure any
width-wise seam between two pieces of plywood is centered on a slat
and that each piece of plywood is independently fastened to that
slat.
[0607] 3. Staple (or nail) the length-wise slats to the width-wise
slats and to the top plywood. Use marking template as needed to
ensure that the staples through the top plywood are centered on the
slats. Make sure any length-wise seam between two pieces of plywood
is centered on a slat and that each piece of plywood is
independently fastened to that slat.
[0608] 4. Using four screws per strip, screw one side of the 9"
galvanized strips to the end and side panels. For twin size
foundations, there will be two on each end panel and three on each
side panel. For all other sizes, there will be three on each end
panel and three on each side panel. They should be evenly spaced
apart. Note that on the end panels, the outside strips should be
5.5" from the panel ends (so as not to interfere with the unfolding
of the side panels), whereas for the side panels, the outside
strips should be flush with the panel ends.
[0609] 5. Place the foam (without adhesive) on a plywood side
panel. Place the fabric over the foam and wrap around to the back
under reasonable tension. It will overlap {fraction (1/2)} inch on
all four edges onto the back. Staple the fabric under tension to
the back on all four edges. Note: These should be normal wood
staples, not the kind coated with hot-melt adhesive that will be
used for the top-to-slat stapling. Repeat for the other side panel
and the two end panels.
[0610] 6. Attach a plywood spacer to the 1.times.2's in every place
where there is a galvanized strip on the corresponding end
panel.
[0611] 7. Keeping the side and end panels parallel to (but not even
with) the top plywood, attach the side and end panels to the
perimeter 1.times.2's by screwing on the galvanized strips. Again
use four screws per strip.
[0612] 8. Fold in the side panels.
[0613] Another example embodiment is illustrated in FIGS. 68a and
68b. This foundation 6801 consists of a 1/4 inch thick plywood top
6802 but in this case has no 1.times.2 stiffener grid as in the
previous two examples. It has a fold-down side as in the previous
example. The fold-down ends of example 2 exist, and are accompanied
by a series of internal panels similar to the ends except not
upholstered. These interior panels act to stiffen the plywood top
in lieu of the 1.times.2 grid. The end and interior panels fold
down an orthogonal angle to the top. The side panels do so also,
and have slots machined in their sides to receive the edges of the
side and interior panels. This embodiment enjoys similar cost and
weight and performance advantages of the previous examples, with
similarly low assembly-on-site labor. However, this embodiment
ships even more compactly, with a folded width of less than 1 inch.
Thus more than seven foundations can be shipped in the space
occupied by one prior art foundation.
[0614] Another example embodiment utilizes a plywood/grid top as in
another example above but without the fold-down sides and ends. The
top is built to have a 1/4 inch overlap of the plywood from the
1.times.2 grid. The top is set into a border frame, consisting of
integral sides and ends. The top may be attached or not as example.
The sides and ends are angled from vertical slightly to allow
stacking of the border frames. If the tops are attached, the
foundations can still stack compactly. If the frames are
unattached, it may be advantageous to stack the border frames and
the tops separately for maximum overall compaction. The border
frame can be made of wood or wood composites. It can also be made
by forming plastic sheet into a frame, such as 1/8-inch thick
polyethylene.
[0615] In the examples above, the top of the plywood can be sprayed
with a pigmented solvated rubber-like thermoplastic to create a
non-slip mattress surface, with the pigment hiding the plywood.
[0616] The devices are not limited to any particular material or
specific configuration so long as it comprises a relatively rigid
top and separate/separable sides which either easily
assemble/disassemble from the top or fold into parallel with the
top. The materials can be any economical structurally sound
material, including but not limited to plywood, oriented strand
board (OSB), chipboard, pressboard, plastic, metal, masonite, or
composite materials. The top is example to be continuous but can be
perforated or discontinuous so long as it provides the needed
overall rigidity and does not have gaps so large as to allow the
mattress to have localized deformation. The size of the allowed
gaps depends on the floppiness of the mattress; e.g., a firm
innerspring mattress can sit atop larger gaps than a foam
mattress.
[0617] The mattress foundations hereof, as illustrated by but not
limited to the examples shown, are different from and superior to
the prior art in several ways:
[0618] 1. Unlike prior art foundations for conventional mattresses,
my foundations ship more compactly, saving considerable expense in
shipping and expanding the market area in which a mattress
manufacturer can compete.
[0619] 2. Unlike prior art foundations for conventional mattresses,
my foundations are more rigid and thus allow less deformation both
in an overall and a local sense.
[0620] 3. Unlike prior art foundations for conventional mattresses
which are inexpensive to produce, my foundations are more durable
because all of the materials of construction are durable (no thin
fabrics, etc.).
[0621] 4. Unlike prior art foundations for conventional mattresses
that use quality fabrics and are thus durable and that use
sufficient metal spacers to effect high rigidity, my foundations
are inexpensive to produce because I use the rigidity and
durability of inexpensive materials such as plywood rather than
labor-intensive and costly heavy steel wire structures bridged with
quality fabrics.
[0622] 5. Unlike prior art foundations for conventional mattresses,
devices herein allow for foundations which collapse to the point
that they can be shipped local delivery truck, and even these
versions do not require labor intensive or tool intensive assembly
by the end user.
[0623] 6. Unlike all known prior art mattress foundations, my
foundations have an anti-slip option.
[0624] The main feature hereof is separate/separable sides/ends in
conjunction with a relatively rigid top or tops which enable(s)
compact shipping. Some of the additional features include but are
not limited to:
[0625] a. The optional use of ductile thin metal as hinges, usable
because the hinges will be actuated very few times and so metal
fatigue failure does not come into play.
[0626] b. The optional pre-application of fabric and other
upholstery materials (such as foam) to the individual sides and/or
ends of a foundation. In prior art foundations, such upholstery is
only applied to the assembled foundation, which prevents some of
the features.
[0627] c. The optional use of a solvated elastomer or melted
elastomer to facilitate the spray or roller application of the
elastomer to a foundation top.
[0628] d. The optional use in general of a non-skid top in a
mattress foundation.
[0629] e. In a foundation, the optional use of a grid (1.times.2's
in the examples) firmly attached to a relatively thin skin
(1/4-inch plywood in the examples) to provide an overall very stiff
top and/or side and/or end structure.
[0630] f. The use of a barbed fastener or other low-labor fasteners
to locate one foundation component relative to another.
[0631] Podalic Pads
[0632] Elastomeric or viscoelastomeric podalic pads using materials
and or structures described herein can be created.
[0633] Elastomer Chews
[0634] These devices includes an elastomeric or viscoelastomeric
chews. The material may be shaped for chewing and may be
impregnated with a substances that slowly releases into the mouth
while being chewed, such as medications, drugs, flavors,
sweeteners, herbs, vitamins, minerals, dietary supplements,
homeopathic remedies, and any other substance that is desired to be
slowly released into the mouth. Most rubbers and elastomers are
non-polar and have a definable solubility factor. Most substances
to be released into the mouth are polar and have a solubility
factor different from elastomers. When blended with an elastomer,
the substance to be released does not chemically bond with the
elastomer, so during chewing the substance to be released
immediately separates from the elastomer. But when the materials
are used, a polar bond is formed between the substance to be
released and the elastomer, so that the substance to be released
works out of the elastomer matrix slowly during chewing. Chewing
the elastomer chew does not fatigue the jaw and mouth of the chewer
as chewing gum does because the elastomer rebounds to its original
shape during chewing rather than sticking to the teeth and creating
suction as chewing gum does.
[0635] Referring to FIGS. 69a, 69b and 69c, a top view, front view
and end view (respectively) of an elastomer chew 6901 are
shown.
Cushions That Include Hollow Column Gel and a Second Cushioning
Element
[0636] Referring to FIGS. 70-85, embodiments which include both a
hollow column gel as described herein and at least a second
cushioning element are shown. The advantages of buckling columns
are already described herein. Combining buckling column cushions
with another cushioning element and at least 30% void space in
stacked sequence is very advantageous. This applies to many
products including beds, mattressing, operating table pads,
stretcher cushions, sofas, chairs, wheelchair seat cushions,
vehicle seats, bicycle seats, forklift seats, truck seats, car
seats, lawnmower seats, motorcycle seats, tractor seats, boat
seats, plane seats, train seat and others.
[0637] FIG. 70 depicts a 2" high hollow column gel elastomer 7001
with 1" square columns and 0.125" wall thickness topped with a
quilted fiber top 7002 as is commonly found in the mattressing art.
This allows the user of the cushion to enjoy breathability between
his body and the gel, and to avoid the high friction of contact
with the gel. Further, since the gel will not touch the user's
skin, the user will not feel cold on touching the cushion.
[0638] FIG. 71 depicts a first hollow column gel cushioning element
7101, a second hollow column gel cushioning element 7102 and a
quilted fiber top 7103 in stacked sequence. The firmness of the
hollow column gel cushioning elements may be varied to increase the
surface area of the user being cushioned.
[0639] FIG. 72 depicts a tall gel column 7002 topped with a quilted
top 7003 that includes fiber 7001 and foam 7004. The foam creates
extra thickness and a bridging effect over the hollow columns,
allowing large columns to be used, such as 6" tall, with 1.8"
square holes and 0.10" wall thickness. Greater hole size reduces
weight and cost of the hollow column gel.
[0640] FIG. 73 depicts a first hollow column gel 7301 that is 6"
high and has 1.8" square holes and 0.10" wall thickness. A second
hollow column gel 7302 is stacked thereon using 2" hollow columns
with 1" square holes and 0.125" wall thickness. That is topped with
a quilted top with fiber 7303. The short columns provide a plush
bridging effect for the deep-sinking tall columns.
[0641] FIG. 74 depicts two short hollow column gel elements 7401
and 7402 atop a tall hollow column gel element 7403 with large
holes, the entire combination topped with a quilted top 7404.
Durometers of the cushioning elements may be varied.
[0642] FIG. 75 depicts a short cushioning element 7501 atop a thick
layer of polyurethane foam 7502, the entire assembly being topped
with a quilted top 7503.
[0643] FIG. 76 depicts a thick layer of polyurethane foam 7601 on
top of which is found a first 7602 and a second 7603 short hollow
column gel cushioning element, followed by a quilted top 7604. This
configuration has good side stability.
[0644] FIG. 77 depicts a slab of high grade visco foam 7701 on top
of which is found a short hollow column gel element 7702 and a
quilted top. Visco foam is also called gel foam and Tfoam.
Visco-form easily forms to the shape of the object being cushioned,
while still providing side stability.
[0645] FIG. 78 depicts a prior art spring unit 7801 which is well
known, followed by a short unit of hollow column gel 7802 and a
quilted top 7803. The gel columns in this embodiment overcome the
peak pressure problems of spring units.
[0646] FIG. 79 depicts a spring unit 7901 topped with a first 7902
and a second 7903 hollow column gel cushion and a quilted top
7904.
[0647] FIG. 80 depicts use of a shallow spring unit 8001 topped
with a thick hollow column gel unit 8002 using large columns, and
the top layer 8003 being a quilted top with foam 8004 for bridging
across the large columns.
[0648] FIG. 81 depicts a slab of latex foam 8101 topped with a
short hollow column gel unit 8102 and a quilted top 8103.
[0649] FIG. 82 depicts another embodiment with a base of tall
hollow column gel with large columns 8201, followed by a latex foam
rubber topper 8202 and a quilted top 18 8203.
[0650] FIG. 83 depicts a tall column hollow column gel element 8301
followed by a layer of latex foam 8302 and a quilted top 8303.
[0651] FIG. 84 depicts a tall hollow column gel element 8401
followed by a layer of polyurethane foam 8402 and a quilted top
8403.
[0652] FIG. 85 depicts a tall unit of hollow column gel 8501 topped
with a layer of pillow soft polyurethane foam 8502 and a quilted
top 8503.
Method for Extruding Large Internally Complex Discontinuous
Structures
[0653] A method for extruding cushioning shapes is provided below.
The method permits the extrusion of polymeric parts of complex
geometry which are short in cut-off length but of large dimension
in one or more dimensions transverse to the material flow.
[0654] A significant problem in extrusion is differential cooling
between the exterior and interior of the part causing shrinkage and
part deformation. Another problem is that air pressure differences
in the part interior causes part blow up or collapse. The larger
the extruded part, the greater these problems are. When hollow
column gel parts are made, the parts will preferably be very large,
such as at least 45 inches square. In the prior art it was not
considered possible to manufacture large, low-durometer gel
products, such as the hollow column gel cushioning elements, by
extrusion, particularly if the part to be extruded is floppy and
does not stand under its own weight.
[0655] Referring to FIG. 86, a novel extrusion die is depicted. The
die is useful in extruding a king sized mattress core in a single
piece, the overall dimensions of which are 76 inches by 79.5 inches
by 6 inches thick. Internally, the example mattress core would
include hollow square columns of about 2 inches by 2 inches with a
wall thickness of about 0.10 inches. The gelatinous elastomer or
viscoelastomer to be used is as described elsewhere herein, but is
low durometer and floppy.
[0656] The extrusion die 8601 is constructed as follows. Note that
the figure depicts only a portion of the whole die, for simplicity.
A steel base plate 8602 of about 80.times.84 inches is machined
flat to a thickness of about 1 inch. Aluminum cores 8603 are
provided attached to the base plate. The aluminum cores are
machined to about 1.95".times.1.95".times.1.5". The cores are
attached to the base plate with a spacing of 0.10" in order to
create hollow column gel with 0.10" wall thickness. As molten
elastomer floods through the space between the cores, the desired
cushioning element shape is formed. A cap plate 8604 is attached to
the base plate, of the same dimension as the base plate. Runners
are machined into the base plate and the cap to permit molten
elastomer to be forced therethrough by a press of sufficient
strength. Small holes 8605 are drilled between the runners and the
spaces 8606 or runways between the cores 8603 to permit molten
elastomer to flow from the runners through the holes and through
the runways to form a cushioning element. The molten material can
flow through the runners much more easily than through the small
drilled holes, resulting in reasonably equalized pressure as the
molten material moves through the runways 8605. Molten material
enters the die 8601 at an input and exits the die 8601 at an output
8608. As the material exits the die at the output, it is
immediately cooled in a water bath 8609 so that from the water bath
exit 8610 a frozen finished part is produced. The use of a water
bath stabilizes the part shape. As material exits the die and
enters the water bath, at an appropriate dimension it will be cut
according to a prior art cutting method. Air pressure is not needed
within the part because the water bath provides even cooling and
part shape stability. In the water bath, there is no tendency of
gravity to cause sidewall collapse of the part. The specific
gravity of the example elastomer is 0.88, near enough the specific
gravity of water (1.0) such that buoyancy will not deform the
part.
[0657] It is example that the water bath be at or near boiling.
This is because as the water inside of cells of the hollow column
gel heats up from the cooling process, it would create a
temperature differential with water outside of the cells which does
not heat up as much. Transfer of heat from the elastomer to the
water causes steam. Vent holes in the cores and plates are provided
to accommodate release of this steam.
[0658] Although the example coolant is water, other flowable
cooling mediums could be used, such as air, glycerin, propylene
glycol, oil, plastic beads, hydraulic fluid, heat transfer fluid,
and other materials that do not deform the elastomer part. If stiff
parts are being made, air may be an appropriate coolant. In some
instances, such as with a low specific gravity part, it is desired
to cut the part off from the die before it enters the water to
avoid deformation due to buoyancy.
[0659] The extrusion example herein is downward extrusion into
water, but upward extrusion is also contemplated. In such a case,
the coolant would be in direct contact with the die face and the
die face would be in a tank of coolant. Parts would tend to buoy up
in the coolant as they exit the die.
[0660] Gel-Coated Fabrics
[0661] Another embodiment is to coat fabrics etc. with a highly
plasticized A-B-A tri-block co-polymer of the SEPS, SEEPS or SEEEPS
variety (styrene-[ethylene-ethylene propylene]-styrene or
styrene-[ethylene-ethylene-ethylene-propylene]-styrene). The EEEP
mid-block is preferably of very high molecular weight, such that
the solution viscosity is so high as to be essentially a solid when
at 20% solids in toluene @ 25 degrees C. Preferably, the
plasticizer is a white paraffinic mineral oil such as Witco LP-200.
Preferably, an fluorochemical such as Dupont Zonyl BA-N is added to
slow or completely prevent the wicking out of the plasticizer. My
most example SEEEPS tri-block co-polymer is Septon 4055 by Kuraray
of Japan. Septon 4055 is a solid elastomeric gel when combined with
toluene at 20% solids @ 25 degrees C., and not a liquid at all, so
that solution viscosity is a meaningless term for Septon 4055.
Septon 4055 exhibits less plasticizer wicking than other
copolymers, and produces a stronger and more durable gel.
[0662] The most example plasticizer to copolymer ratio for fabric
coatings is in the range of 4-to-1 to 2-to-1. More or less
plasticizer is allowable within the scope. More plasticizer is not
example for most applications because the tackiness of the gel is
higher as plasticizer content increases. Less plasticizer is not
example for most applications because the lower the plasticizer
content, the more effect on suppleness will be noticed.
[0663] The need exists for an additive which substantially reduces
and preferably completes stops wicking of the plasticizer. The
fabric coating thus preferably includes an additive such as is
fully described above. As stated above, my most example additive is
Dupont's fluorochemical alcohol Zonyl BA-N, added at 0.05% to
0.75%, typically 0.20% to 0.35%, of the total gel weight. Other
fluorochemicals, particularly fluorochemical alcohols and
surfactants, are also example anti-wicking additives in the
coating.
[0664] The results of applying my example gel coating to a fabric
are excellent. Because the durometer is so low (Shore A10 at the
highest, but usually well below the Shore A scale altogether), the
suppleness of the fabric is virtually unaffected. Since it can
stretch to as much as twenty times its original length without
permanent set, and since it is of such low durometer, the
stretchiness of fabrics such as Dupont's Lycra is virtually
unaffected. It is essentially water proof. It has a low degree of
air permeability, so that in very thin coatings it allows some
breathing of air and vapors, and with somewhat thicker coatings is
for all practical purposes gas impermeable. It is very lightweight,
with a density of 0.86 to 0.88 grams per cubic centimeter (as a
comparison, silicone gel is about 0.98, polyurethane film is about
1.25, and rubber density varies depending on fillers used but is
generally more than that of my example gel. It is relatively
inexpensive, costing about 80% as much as Mr. Chen's example gels,
50% as much as neoprene, and 30% as much as polyurethane film. It
does not wick plasticizer at all at room temperature when placed
next to photocopier paper.
[0665] The example gel can be applied to fabrics in a variety of
ways. One example method is to solvate the gel ingredients in
toluene or another organic solvent, using enough toluene to produce
the viscosity desired. The solvated gel is coated onto the fabric
by coating means well known in the art, such as a roller and doctor
blade, then the toluene is evaporated off, usually with heat, and
usually recovered so as to prevent air pollution. Another example
method is to heat and shear the gel ingredients at sufficient
temperature (usually 350 to 400 degrees F. is sufficient) that a
thoroughly molten and mixed fluid is obtained. The molten fluid is
then coated onto the fabric with similar means as in the solvated
case, and the molten gel is allowed to cool and solidify. Other
means are also feasible, including but not limited to extruding the
molten gel into a film, cooling it, then heat-laminating the film
to the fabric. Other methods might include hot molten gel spray and
solvated gel spray.
[0666] This disclosure is not to be limited by the foregoing
preferences and examples. Any type of fabric or other pliable,
porous material (including but not limited to paper and foam)
coated with or laminated to the range of gels described above or
coated with or laminated to any plasticized elastomer containing
anti-wicking additives or bleed-reducing additives as described
above also falls within the scope. Any method of applying the
coating or laminated layer is acceptable.
Summary of Some Alternative Embodiments
[0667] Referring to FIGS. 87-97, various alternative embodiments
are depicted. Each of these is a cushioning device which may be
incorporated into any type of cushion desired.
[0668] FIG. 87 depicts a base of a non-skid (high friction) fabric
8701 on which a cushioning element 8702 is found topped by a
pearlized chintz quilt with foam and fiber 8703. The cushioning
element 8702 has buckling foam rails.
[0669] FIG. 88 depicts a base of non-skid fabric 8801 under a
buckling foam rail cushioning element 8802 and topped with a
pearlized chintz pillow top with foam, convoluted foam and
fiber.
[0670] FIG. 89 depicts a base of Belgian damask tick 8901 on which
a cushioning element 8902 of foam buckling rails is place. On top
of that is found a layer of supersoft latex foam 8903 followed by a
top of Belgian damask quilt with foam and fiber 8904.
[0671] FIG. 90 depicts a base of Belgian damask tick 9001 which has
a buckling rail cushioning element 9002 on top of it with buckling
rails in only one direction, followed by a buckling rail cushioning
element 9003 that has buckling roam rails in two directions,
followed by a layer of supersoft latex foam 9004 and a top of
Belgian damask quilt with foam and fiber.
[0672] FIG. 91 depicts a base of Belgian damask tick 9101 on which
is a cushioning element 9102 with buckling roam rails in two
directions, a second cushioning element 9103 with buckling foam
latex rails in two directions, a layer of supersoft latex foam 9104
and a top of Belgian damask tick with supersoft fiber.
[0673] FIG. 92 depicts a base of Belgian damask tick 9201 on top of
which is a cushioning element 9202 of hollow column gel surrounded
by border-stiffening foam and a foam base, and a top 9203 of
Belgian damask quilt with foam and fiber.
[0674] FIG. 93 depicts a base 9301 of Belgian damask tick followed
by a cushioning element 9302 of gel hollow columns bordered by foam
and with a foam base, followed by two-dimension buckling rail foam
9303 and a top of Belgian damask quilt with foam and fiber
9304.
[0675] FIG. 94 depicts a base of non-skid fabric 9401 followed by
mattress inner springs 9402, then by buckling rail foam with rails
in two directions 9403 and a top of pearlized chintz quilt with
foam and fiber.
[0676] FIG. 95 depicts a base of Belgian damask tick 9501 under
metal mattress inner springs 9502 followed by a cushioning element
9503 with foam latex buckling rails in two directions, and a top
9504 of Belgian damask quilt with supersoft fiber.
[0677] FIG. 96 depicts a cushioning element 9601 of buckling foam
rails in two directions with foam borders, a foam base and a foam
top, a second unit of 2 inches of memory foam 9602 and a stretch
knit cover 9603.
[0678] FIG. 97 depicts a cushioning element 9701 of buckling latex
foam rails in two directions, with a layer 9702 of latex foam on
top followed by a stretch knit cover 9704.
[0679] The reader should note that any other manufacturing method
may be used which results in a cushioning element having the
general configuration of or achieving the object hereof. Such other
methods may include but are not limited to rotational molding of a
cushioning media such as a hot liquid gel, and vacuum forming of
sheets of a cushioning media such as gel.
[0680] While the present devices, methods and materials have been
described and illustrated in conjunction with a number of specific
embodiments, those skilled in the art will appreciate that
variations and modifications may be made without departing from the
principles as herein illustrated, described, and claimed.
[0681] The present devices, materials and methods may be embodied
in other specific forms without departing from its spirit or
essential characteristics. The described embodiments are to be
considered in all respects as only illustrative, and not
restrictive. The scope of the invention is, therefore, indicated by
the appended claims, rather than by the foregoing description. All
changes which come within the meaning and range of equivalency of
the claims are to be embraced within their scope.
* * * * *