U.S. patent application number 10/364921 was filed with the patent office on 2003-12-25 for method for making gel including salt reduction step.
This patent application is currently assigned to EdiZONE, LC. Invention is credited to Pearce, Tony M..
Application Number | 20030234462 10/364921 |
Document ID | / |
Family ID | 29739440 |
Filed Date | 2003-12-25 |
United States Patent
Application |
20030234462 |
Kind Code |
A1 |
Pearce, Tony M. |
December 25, 2003 |
Method for making gel including salt reduction step
Abstract
Methods for making formable polymers including elastomeric gels
resulting in a formable polymer having air voids or pockets are
disclosed. The methods can include forming a formable polymer
around salt particles or other dissolvable particles, permitting
the formable polymer to solidify, then reducing the salt or other
dissolvable particles by use of water or a solvent or melting,
leaving air pockets or voids in the formable polymer.
Inventors: |
Pearce, Tony M.; (Alpine,
UT) |
Correspondence
Address: |
Parsons Behle & Latimer
201 South Main Street, Suite 1800
P.O. Box 45898
Salt Lake City
UT
84111
US
|
Assignee: |
EdiZONE, LC
|
Family ID: |
29739440 |
Appl. No.: |
10/364921 |
Filed: |
February 11, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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60356279 |
Feb 11, 2002 |
|
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Current U.S.
Class: |
264/49 |
Current CPC
Class: |
Y10T 428/1352 20150115;
A23V 2250/54246 20130101; A23V 2250/5076 20130101; A23V 2250/5432
20130101; A23V 2250/54246 20130101; A23V 2250/264 20130101; A23V
2002/00 20130101; A23P 10/30 20160801; A61K 9/0056 20130101; A23G
3/54 20130101; A23P 20/20 20160801; A63B 2208/12 20130101; Y10T
428/31786 20150401; A63H 33/04 20130101; C08J 2201/0444 20130101;
B32B 27/36 20130101; B41M 5/0355 20130101; A23G 3/36 20130101; A23L
27/79 20160801; Y10T 428/2861 20150115; A23V 2002/00 20130101; A63B
43/008 20130101; A23G 3/50 20130101; A23V 2002/00 20130101; A63H
33/28 20130101; C08J 9/26 20130101; A63B 2037/085 20130101; B65D
65/463 20130101; Y10T 428/24744 20150115; A23G 3/368 20130101; A23V
2002/00 20130101; Y10S 428/91 20130101; B43M 99/006 20130101; B43K
23/008 20130101; A23V 2250/056 20130101; A23V 2250/5118 20130101;
A23V 2250/642 20130101; A23V 2250/056 20130101; A23V 2250/264
20130101; A23V 2250/5036 20130101; A23V 2250/6406 20130101; A23V
2250/5432 20130101; A23V 2200/222 20130101; A23V 2200/16 20130101;
A23V 2250/2482 20130101; A23V 2250/2482 20130101; A23V 2250/242
20130101; A23V 2250/5036 20130101; A23V 2250/5118 20130101 |
Class at
Publication: |
264/49 |
International
Class: |
B29C 044/02 |
Claims
What is claimed is:
1. A method for making a course foamed material comprising the
steps of: selecting a material to be foamed selected from the group
consisting of elastomer gels, thermoplastic materials, thermoset
materials and cross-linkable materials, separating the material to
be foamed into distinct particles, mixing a quantity of discrete
units of dissolvable substance with the particles, agglomerating
the particles and the discrete units together to form a generally
solid component that includes discrete units of dissolvable
substance within, introducing a solvent to the solid component,
reducing the discrete units of dissolvable substance by use of said
solvent to leave voids in said solid component so that solid
component has the appearance of a course foam.
2. A method as recited in claim 1 wherein said agglomeration step
includes a process selected from the group consisting of pressing,
heating, fusing and binding said particles together.
3. A method as recited in claim 1 wherein said agglomeration step
is conducted in a mold.
4. A method as recited in claim 1 wherein at least some of said
discrete units of dissolvable substance are salt.
5. A method as recited in claim 1 wherein at least some of said
discrete units of dissolvable particles are water soluble.
6. A method as recited in claim 1 wherein said solvent is
water.
7. A method as recited in claim 1 wherein at least some of said
discrete units of dissolvable particles are at least partially
solvated prior to said agglomerating step.
8. A method as recited in claim 1 wherein said foam is soft,
stretchable, strong and supple.
9. A method for making a course foamed material comprising the
steps of: selecting an elastomer gel material to be foamed wherein
said elastomer gel includes: an elastomer, and a plasticizer,
separating the material to be foamed into distinct particles,
mixing a quantity of discrete units of dissolvable substance with
the particles, agglomerating the particles and the discrete units
together to form a generally solid component that includes discrete
units of dissolvable substance within, introducing a solvent to the
solid component, reducing the discrete units of dissolvable
substance by use of said solvent to leave voids in said solid
component so that solid component has the appearance of a course
foam; wherein said foam is soft, stretchable, strong and
supple.
10. A method as recited in claim 1 wherein said agglomeration step
includes a process selected from the group consisting of pressing,
heating, fusing and binding said particles together; and wherein
said agglomeration step is conducted in a mold.
11. A method as recited in claim 1 wherein at least some of said
discrete units of dissolvable substance are salt; and wherein said
solvent is water.
12. A method as recited in claim 9 wherein said elastomer is an
A-B-A triblock copolymer.
13. A method as recited in claim 12 wherein said A-B-A triblock
copolymer is selected from the group consisting of SEPS, SEBS and
SEEPS.
14. A method as recited in claim 9 wherein said elastomer gel has a
hardness in the durometer range of from less than 0 to about 50 on
the Shore A scale.
15. A method as recited in claim 9 wherein said elastomer gel is
substantially solid and non-flowable at room temperature.
16. A method for making a course foamed material comprising the
steps of: selecting a elastomer gel material to be foamed wherein
said elastomer gel includes: an elastomer, said elastomer being an
A-B-A triblock copolymer, said A-B-A triblock copolymer being
selected from the group consisting of SEPS, SEBS and SEEPS, and a
plasticizer, said plasticizer being selected from the group
consisting of resin, rosin, oil and combinations thereof,
separating the material to be foamed into distinct particles,
mixing a quantity of discrete units of dissolvable substance with
the particles, agglomerating the particles and the discrete units
together to form a generally solid component that includes discrete
units of dissolvable substance within, introducing a solvent to the
solid component, reducing the discrete units of dissolvable
substance by use of said solvent to leave voids in said solid
component so that solid component has the appearance of a course
foam; wherein said foam is soft, stretchable, strong and
supple.
17. A method as recited in claim 16 wherein said elastomer gel has
a hardness in the durometer range of from less than 0 to about 50
on the Shore A scale.
18. A method as recited in claim 16 wherein said elastomer gel is
substantially solid and non-flowable at room temperature.
19. A method for making a course foamed material comprising the
steps of: accessing particles of a material to be foamed, mixing a
quantity of discrete units of dissolvable substance with the
particles, agglomerating the particles and the discrete units
together to form a generally solid component that includes discrete
units of dissolvable substance within, introducing a solvent to the
solid component, and reducing the discrete units of dissolvable
substance by use of said solvent to leave voids in said solid
component so that solid component has the appearance of a course
foam.
20. A method for making a course foamed material comprising the
steps of: selecting a material to be foamed selected from the group
consisting of elastomer gels, thermoplastic materials, thermoset
materials and cross-linkable materials, selecting a quantity of
discrete units of dissolvable substance with the particles,
agglomerating the discrete units of dissolvable particles together
to form a generally solid component with interstitial spaces,
causing molten material to be foamed into said interstitial spaces
and permitting said molten material to solidify, introducing a
solvent to the solid component, reducing the discrete units of
dissolvable substance by use of said solvent to leave voids in said
solid component so that solid component has the appearance of a
course foam made from said material to be foamed.
21. A method as recited in claim 20 wherein said agglomeration step
includes a process selected from the group consisting of pressing,
heating, fusing and binding.
22. A method as recited in claim 20 wherein said agglomeration step
is conducted in a mold.
23. A method as recited in claim 20 wherein at least some of said
discrete units of dissolvable substance are salt.
24. A method as recited in claim 20 wherein at least some of said
discrete units of dissolvable particles are water soluble.
25. A method as recited in claim 20 wherein said solvent is
water.
26. A method as recited in claim 20 wherein at least some of said
discrete units of dissolvable particles are at least partially
solvated prior to said agglomerating step.
27. A method as recited in claim 1 wherein said foam is soft,
stretchable, strong and supple.
28. A method for making a course foamed material comprising the
steps of: selecting an elastomer gel material to be foamed wherein
said elastomer gel includes: an elastomer, and a plasticizer,
selecting discrete units of dissolvable substance, agglomerating
the discrete units together to form a generally solid component
with interstitial spaces, causing said elastomer gel to be present
in said interstitial spaces, introducing a solvent to the solid
component, reducing the discrete units of dissolvable substance by
use of said solvent to leave voids in said solid component so that
solid component has the appearance of a course foam of elastomer
gel; wherein said foam is soft, stretchable, strong and supple.
29. A method as recited in claim 29 wherein said agglomeration step
includes a process selected from the group consisting of pressing,
heating, fusing and binding; and wherein said agglomeration step is
conducted in a mold.
30. A method as recited in claim 29 wherein at least some of said
discrete units of dissolvable substance are salt; and wherein said
solvent is water.
31. A method as recited in claim 28 wherein said elastomer is an
A-B-A triblock copolymer.
32. A method as recited in claim 31 wherein said A-B-A triblock
copolymer is selected from the group consisting of SEPS, SEBS and
SEEPS.
33. A method as recited in claim 32 wherein said elastomer gel is
substantially solid and non-flowable at room temperature.
34. A method for making a course foamed material comprising the
steps of: selecting a elastomer gel material to be foamed, wherein
said elastomer gel includes: an elastomer, said elastomer being an
A-B-A triblock copolymer, said A-B-A triblock copolymer being
selected from the group consisting of SEPS, SEBS and SEEPS, and a
plasticizer, said plasticizer being selected from the group
consisting of resin, rosin, oil and combinations thereof, selecting
a quantity of discrete units of dissolvable substance,
agglomerating the discrete units together to form a generally solid
component that includes interstitial spaces, causing said elastomer
gel to be present in said interstitial spaces, introducing a
solvent to the solid component, reducing the discrete units of
dissolvable substance by use of said solvent to leave voids in said
solid component so that the solid component has the appearance of a
course foam of elastomer gel; wherein said foam elastomer gel is
soft, stretchable, strong and supple.
35. A method as recited in claim 34 wherein said elastomer gel is
substantially solid and non-flowable at room temperature.
36. A method for making a course foamed material comprising the
steps of: accessing a material to be foamed, accessing a quantity
of discrete units of dissolvable substance, agglomerating said
discrete units into a solid component with interstitial spaces
therein, introducing said material to be foamed into said
interstitial spaces, introducing a solvent to the solid component,
and reducing the discrete units of dissolvable substance by use of
said solvent to leave voids in said solid component so that solid
component has the appearance of a course foam.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] PRIORITY: I hereby claim the benefit under Title 35, U.S.C.
.sctn. 119(e) of a U.S. Provisional Patent Application filed on
Feb. 11, 2002 and having Ser. No. 60/356,279. I hereby claim the
benefit under Title 35 U.S.C. .sctn. 120 of each of the following:
U.S. patent application Ser. No. 10/164,832 filed on Jun. 7, 2002,
which is a continuation-in-part of U.S. patent application Ser. No.
09/932,393 filed 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 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, which claims
priority to United States Provisional Patent Application Serial No.
60/021,109 filed on Jul. 1, 1996. I hereby also claim the benefit
under Title 35 U.S.C. .sctn. 120 of each of the following: 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. 09/303,979 filed on 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, which claims priority to U.S. Provisional
Patent Application Serial No. 60/021,109 filed on Jul. 1, 1996. I
hereby also claim the benefit under Title 35 U.S.C. .sctn. 120 of
each of the following: U.S. patent application Ser. No. 09/952,035
filed on September 11, now ______, which is a continuation-in-part
of U.S. patent application Ser. No. 09/932,393 filed 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 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, which claims priority to United States
Provisional Patent Application Serial No. 60/021,109 filed on Jul.
1, 1996. Each of the foregoing is hereby incorporated by
reference.
BACKGROUND
[0002] In the past, if it was desired to have a gel that had voids
or air pockets in it, the gel could be made by foaming or by
injection molding it into its desired shape.
SUMMARY
[0003] Methods for making gel that has voids or air pockets in it
are disclosed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIGS. 1 and 2 depict gel that has been formed to have voids
or air pockets according to disclosed methods.
DETAILED DESCRIPTION
[0005] Referring to FIG. 1, an example gel 101 is depicted that has
been formed to have voids or air pockets 103 within the elastomer
gel material 102 made according to disclosed methods. This example
has been formed using large salt pellets about 10-20 mm in length.
The methods disclosed herein can be used to make void-filled
elastomer gels, such as the gels disclosed in detail below, or to
make any type of void-filled thermoplastic or thermoset material,
or any type of cross-linkable material. Referring to FIG. 2,
another example gel 201 has been formed to have finer voids or air
pockets 202 by using rock salt.
[0006] First, start with an elastomer gel, thermoplastic material,
thermoset material or cross-linkable material. Second, cut or
separate the material into distinct particles or pieces. Third, mix
a quantity of discrete units of dissolvable substance such as rock
salt with the particles. Fourth, agglomerate, press, heat, fuse, or
bind the particles together with the discrete units to form a solid
component of gel, thermoset material, etc. that includes the
discrete units of dissolvable substance within. This step can be
conducted in a mold if desired. The discrete units can be wet or
lightly solvated before mixing with the particles if desired.
Alternatively, the discrete units of dissolvable substance can be
agglomerated, pressed, heated, fused, or bound first, and then the
elastomer gel, thermoplastic material, thermoset material or
cross-linkable material can be injected into the voids of the
dissolvable substance. Next, reduce the discrete units of
dissolvable substance such as by introducing water or a solvent or
by increasing the temperature until the dissolvable substance melts
out or is otherwise reduced. This is generically referred to as a
salt-reducing step. The result is a solid unit of elastomer gel,
thermoplastic material, thermoset material, or cross-linkable
material formed with voids and air pockets in it to have a
relatively coarse foamed appearance. Such a foam can be very soft,
stretchable, strong and have high hand (supple). Such methods are
very useful in achieving foam in materials that are difficult or
impossible to foam by traditional methods. As an example of the
above process: Pellets of elastomeric gel as described below is
mixed with salt pellets such as Morton Salt Pellets for water
softeners, sold by the Morton Salt Company and commonly available
in grocery stores. The mixture is heated to 300 degrees F., which
melts the elastomeric gel pellets but does not affect the salt
pellets. The mixture of molten gel and salt pellets is pressed at
1,000 psi in a mold and cooled under pressure. The mold is opened
and the resultant gel/salt mass is removed and placed in water. The
water dissolves out most of the salt. The water is able to reach
all the salt pellets because the earlier 1,000 psi pressure ensured
that each salt pellet was touching another salt pellet, making
channels from pellet to pellet as the water dissolves the salt.
After the salt is dissolved, the water is allowed to escape or is
squeezed out of the gel. The resultant gel is lighter weight and
softer than would be a solid block of the same gel. It is also
easier to elongate and has a better hand (is more supple). In
another example with the same materials, the salt pellets are first
wet with water and then placed into a mold and allowed to dry. The
water on the surface of the pellets fuses the salt pellets at the
contact points. The salt pellets are now fused into a single
structure with the shape of the mold cavity. With for example an
injection molder, molten gel is then driven by pressure into the
voids of the salt structure and the gel is allowed to cool. The
salt is removed as in the prior example and the result is the same.
This method may provide better reliability in the water reaching
all of the salt pellets in the case wherein the molten gel is of
high viscosity.
[0007] Elastomeric gel as used herein shall mean any elastomeric
gel as exemplified by gels of the several patents and patent
applications to which priority is cited above, and others which may
be known or become known at a later date. As an example, such gels
may include combination of an elastomer and a plasticizer. The
elastomer may be any appropriate elastomer, including but not
limited to A-B-A triblock copolymers such as SEPS, SEBS, SEEPS and
others.
[0008] KRATON.RTM. and SEPTON.RTM. are examples of trade names used
to identify some A-B-A triblock copolymers that may be used to make
elastomer gels. Suitable plasticizers for elastomer gels include
oils such as mineral oils, resins, rosins and others. Other
components may be used in the gel as well, such as antioxidants,
colorants, bleed reducing additives, microspheres and other
components. The elastomer gel or gelatinous elastomer can be made
quite tacky by the addition of resins and other sticky or tacky
plasticizers. The elastomer gel may be manufactured by solvent
blending, melt blending or compounding under heat and pressure such
as by use of a single screw or twin screw compounding machine or
otherwise.
[0009] Example elastomeric gels that can be considered for
discussion purposes herein include, in parts by weight:
1 EXAMPLE ELASTOMER GEL FORMULA 20 parts Septon 4055 SEPS tri-block
copolymer, available from Kuraray of Japan 60 parts Duoprime 90
white paraffinic mineral oil available from Lyondell of Houston,
Texas 0.3 parts blaze orange aluminum lake pigment available from
Day-Glo Corporation of Twinsburg, Ohio 0.1 parts Irgannox 1076
antioxidant available from Ciba Geigy of Basel, Switzerland ANOTHER
EXAMPLE ELASTOMER GEL FORMULA 20 parts Septon 4044 SEPS triblock
copolymer, available from Kuraray of Japan 20 parts Septon 4055
SEPS triblock copolymer, available from Kuraray of Japan 70 parts
Duoprime 90 white paraffinic mineral oil available from Lyondell of
Houston, Texas 0.1 part aluminum lake blue pigment 0.1 part
Irgannox 1076 antioxidant A THIRD EXAMPLE ELASTOMER GEL FORMULA 40
parts Septon 4055 SEPS triblock copolymer, available from Kuraray
of Japan 120 parts Duoprime 90 white paraffinic mineral oil
available from Lyondell of Houston, Texas 0.1 part aluminum lake
blue pigment 0.1 part Irgannox 1076 antioxidant A FOURTH EXAMPLE
ELASTOMER GEL FORMULA 20 parts Septon 4055 SEPS triblock copolymer,
available from Kuraray of Japan 20 parts Septon 4077 SEPS triblock
copolymer, available from Kuraray of Japan 140 parts Duoprime 90
white paraffinic mineral oil available from Lyondell of Houston,
Texas 0.1 part aluminum lake blue pigment 0.1 part Irgannox 1076
antioxidant
[0010] Elastomer gels used to make the devices may be of any
desired softness or rigidity, but some examples will be in the
durometer range of from less than 0 to about 50 on the Shore A
scale.
[0011] The manufacture of a gelatinous elastomer can be as
disclosed in the patents and patent applications to which priority
is claimed and may include any of melt blending, solvent blending
or compounding by use of heat and pressure such as by using a
single screw or twin screw compounding machine, or otherwise.
[0012] Elastomer Component
[0013] Compositions of elastomer gels maybe low durometer (as
defined below) thermoplastic elastomeric compounds and
visco-elastomeric compounds which include an elastomeric block
copolymer component and a plasticizer component.
[0014] The elastomer component may include a triblock polymer of
the general configuration A-B-A, wherein the A represents a
crystalline polymer such as a monoalkenylarene polymer, including
but not limited to polystyrene and functionalized polystyrene, and
the B is an elastomeric 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.
[0015] An example elastomer for making the elastomer 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 degrees 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 gel are
substantially greater than 30,000 cps. The solution viscosities, in
90 weight percent toluene, of the A-B-A elastomers useful in the
elastomer component of the gel are in the range of about 2,000 cps
to about 20,000 cps. Thus, the elastomer component of the gel
material may have a very high to ultra high molecular weight.
[0016] The elastomeric B portion of the 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).
[0017] The elastomer used may be an ultra high molecular weight
polystyrene-hydrogenated poly(isoprene+butadiene)-polystyrene, such
as those sold under the brand names SEPTON.RTM. 4044, SEPTON.RTM.
4055 and SEPTON.RTM. 4077 by Kuraray, an ultra high molecular
weight polystyrene-hydrogenated polyisoprene-polystyrene such as
the elastomers made by Kuraray and sold as SEPTON.RTM. 2005 and
SEPTON.RTM. 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.RTM. 4033
by Kuraray, are also useful in some formulations of the gel
material because they are easier to process than the ultra high
molecular weight elastomers due to their effect on the melt
viscosity of the material.
[0018] Following hydrogenation of the midblocks of each of
SEPTON.RTM. 4033, SEPTON.RTM.) 4045, SEPTON.RTM. 4055, and
SEPTON.RTM. 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.
[0019] SEPTON.RTM. 4055 has a very high molecular weight
(approximately 300,00, as determined by Applicant's gel permeation
chromatography testing). SEPTON.RTM. 4077 has a somewhat higher
molecular weight, and SEPTON.RTM. 4045 has a somewhat lower
molecular weight than SEPTON.RTM. 4055. Materials which include
either SEPTON.RTM. 4045 or SEPTON.RTM. 4077 as the primary block
copolymer typically have lower tensile strength than similar
materials made with SEPTON.RTM. 4055.
[0020] Kuraray Co. Ltd. of Tokyo, Japan has stated that the
solution viscosity of SEPTON.RTM. 4055, the most A-B-A triblock
copolymer for use in gel material, 10% solids in 90% toluene at 25
degrees C., is about 5,800 cps. Kuraray also said that the solution
viscosity of SEPTON 4055, 5% solids in 95% toluene at 25 degrees
C., is about 90 cps. Although Kuraray has not provided a solution
viscosity, 20% solids in 80% toluene at 25 degrees C., an
extrapolation of the two data points given shows that such a
solution viscosity would be about 400,000 cps.
[0021] 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.RTM. 4055. When SGS attempted to
dissolve 20% solids in 80% toluene at 25 degrees 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 degrees C., which resulted in a 3,040 cps solution.
[0022] Other materials with chemical and physical characteristics
similar to those of SEPTON.RTM. 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.RTM.) 4055.
[0023] Mixtures of block copolymer elastomers are also useful as
the elastomer component of some of the formulations. 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.
[0024] In particular, the process of compounding SEPTON.RTM. 4055
with plasticizers may be improved via a lower melt viscosity by
using a small amount of more flowable elastomer such as SEPTON.RTM.
8006, SEPTON.RTM. 2005, SEPTON.RTM. 2006, or SEPTON.RTM. 4033, to
name only a few, without significantly changing the physical
characteristics of the material.
[0025] In a second example of the usefulness of block copolymer
elastomer mixtures in the 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. KRATON.RTM. G1701,
manufactured by Shell Chemical Company of Houston, Tex., is one
such elastomer that improves the uniformity with which the
components of the gel material mix.
[0026] Many other elastomers, including but not limited to triblock
copolymers and diblock copolymers are also useful in the elastomer
gel. Applicant believes that elastomers having a significantly
higher molecular weight than the ultra-high molecular weight
elastomers useful in the elastomer 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 gel material due to the strength of such
elastomers when combined with a plasticizer.
[0027] Additives
[0028] Polarizable Plasticizer Bleed-Reducing Additives
[0029] Some of the elastomer gel materials described herein 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. Gel materials with higher
plasticizer to polymer ratios may exhibit migration (bleed) and a
bleed reducing additive is helpful to address the bleed issue.
[0030] A plasticizer bleed-reducing additive that may be useful in
the elastomer gel material includes hydrocarbon chains with readily
polarizable groups thereon. Such polarizable groups include,
without limitation, halogenated hydrocarbon groups, halogens,
nitrites, 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 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 attracted to an
elastomeric block by means of a bleed-reducing additive.
[0031] The bleed-reducing additives may 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.
[0032] The bleed-reducing additives may be halogenated hydrocarbon
additives such as those sold under the trade name DYNAMAR.RTM.
PPA-791, DYNAMAR.RTM. PPA-790, DYNAMAR.RTM. 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 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 ZONY.RTM., including without limitation FSN 100, FSO
100, PFBE, 8857A, 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; other
halogenated hydrocarbons sold by 3M under the trade name
DYNAMAR.RTM..; chlorinated polyethylene elastomer (CPE),
distributed by Harwick, Inc. of Akron, Ohio; chlorinated paraffin
wax, distributed by Harwick, Inc.; and others. The bleed reducing
additives may be hydrocarbon resins, elastomeric diblock
copolymers, polyisobutylene, butyl rubber, or transpolyoctenylene
rubber ("tor rubber").
[0033] Detackifiers
[0034] The elastomer gel may include a detackifier. Tack is not
necessarily desired. However, some of the elastomer gel formulas
impart tack to the media.
[0035] Soaps, detergents and other surfactants have detackifying
abilities and are useful in the 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 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.
[0036] Other detackifiers include glycerin, epoxidized soybean oil,
dimethicone, tributyl phosphate, block copolymer polyether,
hydrocarbon resins, polyisobutylene, butyl rubber ,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.RTM. . 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, III 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-I-SE. Other
emulsifiers and dispersants are also useful in the gel material.
Tetraethyleneglycol dimethyl ether is available under the trade
name TETRAGLYME.RTM. from Ferro Corporation of Zachary, La.
Applicant believes that TETRAGLYME.RTM. also reduces plasticizer
exudation from the gel material.
[0037] Antioxidants
[0038] The elastomer gel material may also include 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.
[0039] Antioxidants protect the gel materials against thermal
degradation during processing, which requires or generates heat. In
addition, antioxidants provide long term protection from free
radicals. An antioxidant inhibits thermo-oxidative degradation of
the compound or material to which it is added, providing long term
resistance to polymer degradation.
[0040] 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.
[0041] 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.
[0042] Most primary antioxidants are known as sterically hindered
phenols. One example of sterically hindered phenol is 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(dimethylethyl)-4-hyd- roxyphenyl]-1
-oxopropoxy]methyl]1 ,3-propa nediyl ester. The FDA refers to
IRGANOX.RTM. 1010 as
tetrakis[methylene(3,5-di-tert-butyl-4-hydroxyhyd-
rocinnimate)]methane. Other hindered phenols are also useful as
primary antioxidants in the material.
[0043] 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.
[0044] Commonly used secondary antioxidants include the chemical
classes of phosphites/phosphonites and thioesters, many of which
are useful in the gel material. The hydroperoxide decomposer can be
a phosphite known as Tris(2,4-di-tert-butylphenyl)phosphite and
marketed by Ciba-Geigy as IRGAFOS.RTM. 168.
[0045] Primary and secondary antioxidants form synergistic
combinations to ward off attacks from both peroxy free radicals and
hydroperoxides.
[0046] Other antioxidants, including but not limited to
multi-functional antioxidants, are also useful in the 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 Ciba-Geigy as IRGANOX.RTM.
E17, are also useful in the gel material.
[0047] The elastomer gel material may include 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.
[0048] The use of excess antioxidants reduces or eliminates tack on
the exterior surface of the 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.
[0049] Flame Retardants
[0050] Flame retardants may also be added to elastomer gel
materials. Flame retardants 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 gel material.
[0051] Chemical blowing agents, such as SAFOAMO.RTM. FP-40,
manufactured by Reedy International Corporation of Keyport, N.J.
and others are useful for making a gel medium that is
self-extinguishing.
[0052] Colorants
[0053] Colorants may also be used in gel materials. Any colorant
which is compatible with elastomeric materials may be used.
Aluminum lake colorants such as those manufactured by Warner
Jenkinson Corp. of St. Louis, Mo. Are available. 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) are also available.
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.
[0054] Paint
[0055] The elastomer gel may also be painted.
[0056] Other Additives
[0057] Melt temperature modifiers useful in the 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.
[0058] Melt viscosity modifiers that tend to reduce the melt
viscosity of the pre-compounded component mixture of the medium
include hydrocarbon resins, transpolyoctenylene rubber, castor oil,
linseed oil, non-ultra high molecular weight thermoplastic rubbers,
surfactants, dispersants, emulsifiers, and others.
[0059] Melt viscosity modifiers that tend to increase the melt
viscosity of the pre-compounded component mixture of the 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.
[0060] Tensile strength modifiers which tend to increase the
tensile strength of the gel material for use in the gel material
include mid block B-associating hydrocarbon resins, non-end-block
solvating hydrocarbon resins which associate with the end blocks,
particulate reinforcers, and others.
[0061] 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.
[0062] Microspheres
[0063] Microspheres may also be added to the gel material. The gel
material may contain up to about 90% microspheres, by volume. In
one microsphere-containing formulation of the gel material,
microspheres make up at least about 30% of the total volume of the
material. A second microsphere-containing formulation of the gel
material includes at least about 50% microspheres, by volume.
[0064] Different types of microspheres contribute various
properties to the material. For example, hollow acrylic
microspheres, such as those marketed under the brand name
MICROPEARL.RTM., 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 gel material, or pre-expanded DE (091-80) acrylic
microspheres from Expancel Inc. of Duluth, Ga.
[0065] In formulations of the material which include hollow acrylic
microspheres, the microspheres 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.
[0066] Hollow microspheres also decrease the specific gravity of
the gel material by creating gas pockets therein. When a gel
material includes microspheres, the microspheres must be dispersed,
on average, at a distance of about one-and-ahalf (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.
Other formulations of the gel material have specific gravities of
less than about 0.65, less than about 0.45, and less than about
0.25.
[0067] MICROPEARL.RTM. and EXPANCEL.RTM. acrylic microspheres are
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.
[0068] Plasticizer Component
[0069] 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 gel
may include oil, resin, a mixture of oils, a mixture of resins,
other lubricating materials, or any combination of the
foregoing.
[0070] Oils
[0071] The plasticizer component of the 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 gel material. The oils may have a viscosity
of about 70 SUS to about 500 SUS at about 100 degrees F. Paraffinic
white mineral oils having a viscosity in the range of about 90 SUS
to about 200 SUS at about 100 degrees F. may be used
[0072] One embodiment of a plasticizer component of the gel
includes paraffinic white mineral oils, such as those having the
brand name DUOPRIME.RTM., by Lyondell Lubricants of Houston, Tex.,
and the oils sold under the brand name TUFFLO.RTM. by Witco
Corporation of Petrolia, Pa. For example, the plasticizer component
of the gel may include paraffinic white mineral oil such as that
sold under the trade name LP-150.RTM. by Witco.
[0073] Paraffinic white mineral oils having an average viscosity of
about 90 SUS, such as DUOPRIME.RTM. 90, are used in other
embodiments of the plasticizer component. Applicant has found that
DUOPRIME.RTM. 90 and oils with similar physical properties can be
used to impart the greatest strength to the gel material.
[0074] 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, isoparaffins or paraffins. 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 various commercially
available oils include: Bayol, Bernol, American, Blandol, Drakeol,
Ervol, Gloria, Kaydol, Litetek, Marcol, Parol, Peneteck, Primol,
Protol, Sontex, and the like.
[0075] Resins
[0076] Resins useful in the plasticizer component include, but are
not limited to, hydrocarbon-derived and rosin-derived resins having
a ring and ball softening point of up to about 150 degrees C., or
from about 0 degrees C. to about 25 degrees C., and a weight
average molecular weight of at least about 300.
[0077] Resins or resin mixtures which are highly viscous flowable
liquids at room temperature (about 23 degrees C.) may be used.
Plasticizers which are fluid at room temperature impart softness to
the gel material. Resins which are not flowable liquids at room
temperature are also useful in the material.
[0078] Some resins used have a ring and ball softening point of
about 18 degrees C.; melt viscosities of about 10 poises (ps) at
about 61 degrees C., about 100 ps at about 42 degrees C. and about
1,000 ps at about 32.degrees C. 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 material
have viscosities including, but not limited to, 1025 stokes, 1018
stokes, 745 stokes, 11 4 stokes, and others.
[0079] Room temperature flowable resins that are derived from
poly-.beta.-pinene and have softenening points similar to that of
REGALREZ.RTM. 1018 are also useful in the plasticizer component of
the medium. One such resin, sold as PICCOLYTE.RTM. S25 by Hercules
Incorporated, has a softening point of about 25 degrees C.; melt
viscosities of about 10 ps at about 80 degrees C., about 100 ps at
about 56 degrees C. and about 1,000 ps at about 41 degrees C.; a
MMAP value of about 88 degrees C.; a DACP value of about 45 degrees
C.; an OMSCP value of less than about -50.degrees C. Other
PICCOLYTE.RTM. resins may also be used in the gel material.
[0080] Another room temperature flowable resin which is useful in
the plasticizer component of the material is marketed as ADTAC.RTM.
LV by Hercules Incorporated. That resin has a ring and ball
softening point of about 5 degrees C.; melt viscosities of about 10
ps at about 62 degrees C., about 100 ps at about 36 degrees C. and
about 1,000 ps at about 20 degrees C.; a MMAP value of about 93
degrees C.; a DACP value of about 44 degrees C.; an OMSCP value of
less than about -40 degrees C.
[0081] 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 10 degrees C.; a Brookfield
Viscosity of about 30,000 cps at about 25 degrees C.; melt
viscosities of about 10 ps at about 53 degrees C. and about 100 ps
at about 34 degrees C.; a 1:1 polyethylene-to-resin ratio cloud
point of about 89 degrees C.; a 1:1 microcrystalline wax-to-resin
ratio cloud point of about 77 degrees C.; and a 1:1 paraffin
wax-to-resin ratio cloud point of about 64 degrees C.
[0082] 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 gel
material. One such solid resin is an aliphatic C-5 petroleum
hydrocarbon resin having a ring and ball softening point of about
98 degrees C.; melt viscosities of about 100 ps at about 156
degrees C. and about 1000 ps at about 109 degrees C.; a 1:1
polyethylene-to-resin ratio cloud point of about 90 degrees C.; a
1:1 microcrystalline wax-to-resin ratio cloud point of about 77
degrees C.; and a 1:1 paraffin wax-to-resin ratio cloud point of
about 64 degrees C. Such a resin is available as WINGTACK.RTM. 95
and is manufactured by Goodyear Chemical Co.
[0083] Polyisobutylene polymers are an example of resins which are
not readily flowable at room temperature and that are useful in the
gel material. One such resin, sold as VISTANEX.RTM. LM-MS by Exxon
Chemical Company of Houston, Tex., has a Tg of -60.degrees C., a
Brookfield Viscosity of about 250 cps to about 350 cps at about 350
degrees F., 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 20 degrees C.
[0084] Glycerol esters of polymerized rosin are also useful as
plasticizers in the gel material. One such ester, manufactured and
sold by Hercules Incorporated as HERCULES.RTM. Ester Gum 10D
Synthetic Resin, has a softening point of about 116 degrees C.
[0085] Many other resins are also suitable for use in the gel
material. In general, plasticizing resins are those which are
compatible with the B block of the elastomer used in the material,
and non-compatible with the A blocks.
[0086] In some formulations, tacky materials may be desirable. In
such formulations, 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.
[0087] Plasticizer Mixtures
[0088] The use of plasticizer mixtures in the plasticizer component
of the gel material is useful for tailoring the physical
characteristics of the gel material. For example, characteristics
such as durometer, tack, tensile strength, elongation, melt flow
and others may be modified by combining various plasticizers.
[0089] 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 degrees F., a viscosity of about 30
centistokes (cSt) at about 40 degrees C., and maximum pour point of
about -35 degrees F.) and up to about 62.5 weight percent of a
resin having physical characteristics similar to those of
REGALREZ.RTM. 1018 (such as a softening point of about 20 degrees
C.; a MMAP value of about 70 degrees C.; a DACP value of about 15
degrees C.; an OMSCP value of less than about -40 degrees C.; all
weight percentages being based upon the total weight of the
plasticizer mixture, could be used in a gel. 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.
[0090] When resin is included with oil in a plasticizer mixture of
the gel 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 REGALREZ.RTM. 1018)
exhibits infinitesimal oil bleed at room temperature, if any, even
when placed against materials with high capillary action, such as
paper.
[0091] The plasticizer:block copolymer elastomer ratio, by total
combined weight of the plasticizer component and the block
copolymer elastomer component in some formulations 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. Plasticizer:block copolymer ratios in the
range of about 2.5:1 to about 8:1 may be more common. A ratio such
as 5:1 provides the desired amounts of rigidity, elasticity and
strength for many typical applications. A plasticizer to block
copolymer elastomer ratio of 2.5:1 has a high amount of strength
and elongation.
[0092] Compounding Methods
[0093] Compounding may be carried out by melt blending, solvent
blending, or compounding under heat and pressure such as by use of
a single screw or twin screw compounding machine.
[0094] While the devices, materials and methods have been described
and illustrated in conjunction with a number of specific examples,
those skilled in the art will appreciate that variations and
modifications may be made without departing from the principles
herein illustrated, described, and claimed. The present invention,
as defined by the appended claims, may be embodied in other
specific forms without departing from its spirit or essential
characteristics. The configurations of lights described herein are
to be considered in all respects as only illustrative, and not
restrictive. All changes that come within the meaning and range of
equivalency of the claims are to be embraced within their
scope.
* * * * *