U.S. patent application number 11/657217 was filed with the patent office on 2007-06-14 for hook fasteners and methods of making the same.
This patent application is currently assigned to Velcro Industries, B.V., a Netherlands corporation. Invention is credited to William P. Clune, Paul A. Dandurand, Wallace L. JR. Kurtz, Alexander J. Neeb, Joseph E. Pierce, Richard J. Schmidt, Ernesto S. Tachauer, Richard W. Tanzer, Heidi S. Tremblay, Brian J. Vanbenschoten.
Application Number | 20070134465 11/657217 |
Document ID | / |
Family ID | 34313071 |
Filed Date | 2007-06-14 |
United States Patent
Application |
20070134465 |
Kind Code |
A1 |
Vanbenschoten; Brian J. ; et
al. |
June 14, 2007 |
Hook fasteners and methods of making the same
Abstract
Methods of making touch fasteners include forming lanes of
polymeric material into a sheet-form base and forming discrete
elements extending from the sheet-form base. Corresponding touch
fasteners are also disclosed.
Inventors: |
Vanbenschoten; Brian J.;
(Rochester, NH) ; Tachauer; Ernesto S.; (Bedford,
NH) ; Kurtz; Wallace L. JR.; (Lunenburg, MA) ;
Tremblay; Heidi S.; (Ft. Lauderdale, FL) ; Dandurand;
Paul A.; (Manchester, NH) ; Clune; William P.;
(Northwood, NH) ; Neeb; Alexander J.; (Alpharetta,
GA) ; Pierce; Joseph E.; (Appleton, WI) ;
Schmidt; Richard J.; (Roswell, GA) ; Tanzer; Richard
W.; (Neenah, WI) |
Correspondence
Address: |
FISH & RICHARDSON PC
P.O. BOX 1022
MINNEAPOLIS
MN
55440-1022
US
|
Assignee: |
Velcro Industries, B.V., a
Netherlands corporation
|
Family ID: |
34313071 |
Appl. No.: |
11/657217 |
Filed: |
January 24, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10666304 |
Sep 18, 2003 |
7172008 |
|
|
11657217 |
Jan 24, 2007 |
|
|
|
Current U.S.
Class: |
428/100 ;
428/99 |
Current CPC
Class: |
A44B 18/0061 20130101;
A61F 13/581 20130101; A61F 13/625 20130101; A44B 18/0049 20130101;
Y10T 156/1715 20150115; Y10T 428/24008 20150115; B29C 2043/465
20130101; Y10T 24/2783 20150115; Y10T 428/24017 20150115; B29L
2031/729 20130101 |
Class at
Publication: |
428/100 ;
428/099 |
International
Class: |
B32B 3/06 20060101
B32B003/06 |
Claims
1. A touch fastener comprising: a composite polymeric sheet
comprising a plurality of longitudinally extending lanes, each lane
joined side-by-side to an adjacent lane; and a plurality of
discrete fastener elements comprising stems extending outwardly
from at least one exposed surface of the composite sheet, wherein
the composite polymeric sheet comprises a first lane comprising a
first polymeric material and a second lane comprising a second
polymeric material comprising a foam.
2. The touch fastener of claim 1, further comprising an engageable
head on a distal end of each stem.
3. The touch fastener of claim 2, wherein the engageable head is
hook-shaped.
4. The touch fastener of claim 1, wherein the lanes are joined at
an interface that comprises the first material and the second
material.
5. The touch fastener of claim 1, further comprising an adhesive
bonding the adjacent lanes.
6. The touch fastener of claim 1, further comprising a third lane
comprising a third material different from the first material and
second material.
7. The touch fastener of claim 6, wherein the third lane is
disposed between the first lane and second lane, and wherein a
first interface comprising the first and third material is defined
between the first and third lanes and a second interface comprising
the second and third materials is defined between the second and
third materials.
8. The touch fastener of claim 1, wherein the plurality of
longitudinally extending lanes are formed by coextrusion.
9. The touch fastener of claim 1, wherein the foam is formed by a
chemical foaming agent.
10. The touch fastener of claim 1, wherein the foam is formed by
injecting gas into the second polymeric material as the second lane
is formed.
11. The touch fastener of claim 1, wherein the second polymeric
material comprises a thermoset material.
12. The touch fastener of claim 1, wherein the composite polymeric
sheet comprises a plurality of lanes comprising first and second
materials.
13. The touch fastener of claim 12, wherein the lanes comprising
the first and second polymeric materials alternate.
14. The touch fastener of claim 1, wherein the first polymeric
material comprises polypropylene.
15. The touch fastener of claim 1, wherein the second polymeric
material comprises an elastomer.
16. The touch fastener of claim 15, wherein the elastomer comprises
a polypropylene-based thermoplastic vulcanizate.
17. The touch fastener of claim 1, wherein the second lane has a
height that is greater than a height of the first lane, each height
being measured from a back surface of the respective lane to the
top surface of the respective lane.
18. The method of claim 1, wherein the at least one exposed surface
of the composite sheet defines a portion of a top surface of the
first lane.
19. A touch fastener comprising: a composite polymeric sheet
comprising a plurality of longitudinally extending lanes, each lane
joined side-by-side to an adjacent lane; and a plurality of
discrete fastener elements comprising stems extending outwardly
from at least one exposed surface of the composite sheet, wherein
the composite polymeric sheet comprises a first lane comprising a
first polymeric material disposed between a second lane and a third
lane, each second and third lane comprising a second polymeric
material comprising a foam.
20. The touch fastener of claim 19, further comprising a fourth and
fifth lane, wherein the forth lane is disposed between the first
lane and second lane, and wherein the fifth lane is disposed
between the first lane and third lane.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation (and claims the benefit
of priority under 35 U.S.C. .sctn. 120) of pending U.S. patent
application Ser. No. 10/666,304, filed Sep. 18, 2003, the contents
of which is hereby incorporated by reference herein in its
entirety.
TECHNICAL FIELD
[0002] This invention relates to fasteners, in particular to hook
and loop type fasteners.
BACKGROUND
[0003] Arrays of molded male fastener elements, e.g., hooks are
often formed integrally with a sheet-form base, to provide a
sheet-form fastener component. This component can then be engaged
with female fastener elements to form a "hook and loop" fastener.
It is generally desirable that the fastener elements have good
strength and toughness, so as to provide strong engagement during
repeated use of the fastener. In some cases, it is also desirable
that the sheet-form base be relatively soft and flexible, e.g., to
allow the base to flex with a fabric article to which it is
attached and to prevent the edges of the sheet-form component from
causing discomfort to the wearer.
[0004] Fastener products such as hook and loop type fasteners find
extensive use in personal care absorbent articles including, but
not limited, to diapers, training pants, disposable swimwear,
incontinence garments and pads, and sanitary napkins.
SUMMARY
[0005] One aspect of the invention features, in general, a method
of making a touch fastener. The method includes coextruding,
side-by-side, a plurality of lanes of polymeric material to form a
sheet-form base. The sheet-sheet form base includes a lane of a
first polymeric material disposed between two lanes of a second
polymeric material, the second polymeric material is different from
the first polymeric material. The method further includes molding a
plurality of discrete fastener element stems extending outwardly
from and integral with the sheet-form base in each of the two lanes
of the second polymeric material and forming engageable heads on
the stems.
[0006] In some implementations, the method further includes molding
discrete fastener element stems extending outwardly from and
integral with the sheet-form base in the lane of the first
polymeric material. Engageable heads may be formed on the discrete
fastener element stems extending outwardly from and integral with
the sheet-form base in the lane of the first polymeric material.
The shape of the fastener elements extending from the first
polymeric material may be different than the shape of the fastener
elements extending from the second polymeric material. The height
of the elements extending from the first and second polymeric
material may be different. A tie layer may be disposed between the
lanes of the first and second polymeric material. In some
embodiments, the sheet-form base includes more than three lanes and
the method further includes arranging the lanes so that lanes of
the first polymeric material alternate with lanes of the second
polymeric material. In other implementations, the method further
includes coextruding a polymeric layer during the coextruding of
the side-by-side polymeric lanes, the polymeric layer is disposed
on the side opposite the molded fastener element stems. In some
embodiments, the method further includes bringing in a polymeric
layer as pre-form during the coextruding of the side-by-side
polymeric lanes, the polymeric layer is disposed on the side
opposite the molded fastener element stems. In yet other
embodiments, the method further includes bonding a polymeric layer
of material to the sheet-form base opposite the fastener element
stems. The coextruding, molding, forming engageable heads and
bonding the polymeric layer may be performed continuously.
[0007] Another aspect of the invention features, in general, a
touch fastener that includes a sheet-form base having a plurality
of lanes of polymeric material including a lane of a first
polymeric material disposed between two lanes of a second polymeric
material, the second polymeric material different from the first
polymeric material. Each of the lanes of the second polymeric
material have a plurality of discrete fastener elements comprising
stems integrally molded with and extending outwardly from the
sheet-form base.
[0008] In some implementations, fastener elements extend outwardly
from and integral with the sheet-form base in the lane of the first
polymeric material. The first polymeric material may be, for
example, an elastomer. The touch fastener may be part of, for
example, a personal care absorbent product.
[0009] Another aspect of the invention features, in general, a
touch fastener that includes a plurality of lanes of polymeric
material, forming a sheet-form base. The sheet-form base includes a
lane of a first polymeric material and a lane of a second polymeric
material, the second polymeric material includes a foam. Extending
outwardly from and integral with the sheet-form base in lanes of
the first polymeric material is a plurality of discrete fastener
elements including stems.
[0010] In some implementations, fastener elements extend outwardly
from and integral with the sheet-form base in the lane of the
second polymeric material that includes a foam. The second
polymeric material may be, for example, a foamed thermoplastic, a
foamed thermoplastic elastomer or a formed thermoset. In other
embodiments, the first and second polymeric material alternate. A
polymeric layer may be bonded to the sheet-form base on the side
opposite the fastener elements. The touch fastener may be part of,
for example, a personal care absorbent product.
[0011] Another aspect of the invention features, in general, a
method of making a touch fastener that includes coextruding,
side-by-side, a plurality of lanes of polymeric material to form a
sheet-form base. The method further includes molding a plurality of
discrete fastener element stems extending outwardly from and
integral with the sheet-form base in lanes of the first polymeric
material and forming engageable heads on the stems. The sheet-form
base includes a lane of a first polymeric material and a second
polymeric material, the second polymeric material includes a
foam.
[0012] In some implementations, the method further includes molding
discrete fastener element stems extending outwardly from and
integral with the sheet-form base in the lane of the second
polymeric material that includes a foam. Engageable heads may be
formed on the stems. A tie layer may be disposed between the first
and second polymeric materials. The foam may be formed by a
chemical foaming agent or by injecting gas into the second lane.
The foam may be a thermoset.
[0013] Another aspect of the invention features, in general, a
method of making a touch fastener that includes bonding a plurality
of discrete side-by-side lanes of polymeric material together to
form a sheet-form base, molding a plurality of discrete fastener
element stems extending outwardly from and integral with the
sheet-form base in lanes of the first polymeric material and
forming engageable heads on the stems. The sheet-form base includes
a lane of a first polymeric material and a second polymeric
material, the second polymeric material includes a foam.
[0014] Another aspect of the invention features, in general, a
touch fastener, including a plurality of lanes and an adjoining
layer of polymeric material to form a sheet-form base, the
adjoining layer is below and integral with the plurality of lanes.
The sheet-form base includes a lane of a first polymeric material
disposed between two lanes of a second polymeric material, the
second polymeric material different from the first polymeric
material. Extending outwardly from and integral with the sheet-form
base, opposite the adjoining layer, in each of the two lanes of the
second polymeric material is a plurality of fastener elements. The
touch fastener may be part of, for example, a personal care
absorbent product.
[0015] Another aspect of the invention features, in general, a
method of making a touch fastener that includes forming a composite
polymeric sheet from at least two different polymeric materials
forming corresponding portions of the sheet and defining a boundary
therebetween. The method further includes forming a plurality of
discrete fastener elements extending outwardly from at least one
exposed surface of the composite sheet, stretching the formed sheet
sufficiently to cause one of the portions to permanently deform to
a greater extent than the other of the portions and reducing
stretch of the sheet to allow differences in stretch response
between the two portions to locally distort a shape of the
sheet.
[0016] In some implementations, the two different polymeric
materials may be coextruded side-by-side, forming a plurality of
lanes, including a lane of a first polymeric material disposed
between two lanes of a second polymeric material.
[0017] Another aspect of the invention features, in general, a
method of making a touch fastener that includes coextruding,
side-by-side, a plurality of lanes of at least two different
polymeric materials, forming a contiguous polymeric sheet. The
method further includes forming a plurality of discrete fastener
elements extending outwardly from at least one portion of the
sheet, forming an adjoining layer of polymeric material and bonding
the adjoining layer to the formed polymeric sheet on a side
opposite the fastener elements, forming a composite. Finally, the
method further includes stretching the formed composite
sufficiently in a lateral direction to cause at least one lane of
the polymeric sheet to separate from an adjacent lane.
[0018] In some implementations, the stretching is performed under
the application of heat. The adjoining layer may be adhesive
coated. In some embodiments, the polymeric material of a lane or
lanes may contain an additive to aid, for example, in the
separation of the lanes upon stretching.
[0019] Another aspect of the invention features, in general, a
touch fastener that includes an undulating composite polymeric
sheet with local peaks and troughs. The composite polymeric sheet
includes at least two different polymeric materials featuring
different degrees of stress. The polymeric materials defining
different portions of the sheet and defining a boundary
therebetween and extending outwardly from at least one surface of
the composite a plurality of molded elements. The touch fastener
may be part of, for example, a personal care absorbent product.
[0020] In some implementations, engageable heads are included on
the stems. In other implementations, the molded elements extend
from both peaks and troughs in the sheet.
[0021] Advantages of the invention may include, for example,
providing a stretchable fastener that has strong engagement during
repeated use. Other advantages may include, for example, providing
a fastener that is relatively soft and flexible, for example, to
allow the base to flex with a fabric article to which it is
attached and to prevent the edges of the sheet-form component from
causing discomfort to the wearer.
[0022] All publications, patent applications, patents, and other
references mentioned herein are incorporated by reference herein in
their entirety for all that they contain.
[0023] Other features and advantages of the invention will be
apparent from the following detailed description, and from the
claims.
DESCRIPTION OF DRAWINGS
[0024] FIG. 1 is a perspective view of a fastener according to one
embodiment.
[0025] FIG. 1A is an enlarged cross-sectional view of a portion of
the fastener shown in FIG. 1, taken along line 1A-1A.
[0026] FIG. 2 is a perspective view of an alternative
embodiment.
[0027] FIG. 2A is an enlarged cross-sectional view of a portion of
the fastener shown in FIG. 2, taken along line 2A-2A.
[0028] FIG. 3 is a diagrammatic view of a process for making a
fastener according to one embodiment.
[0029] FIG. 3A is an enlarged diagrammatic view of the portion of
the process of FIG. 3 shown in box A.
[0030] FIG. 4 is a diagrammatic view of a process for making a
fastener according to an alternative embodiment.
[0031] FIG. 4A is a perspective view of a fastener made by the
process shown in FIG. 4.
[0032] FIG. 4B is a diagrammatic view of a process for making a
fastener according to an alternative embodiment.
[0033] FIG. 4C is a cross-sectional view showing other hook shapes
that can be produced by the process shown in FIG. 4B.
[0034] FIG. 4D is a cross-sectional view showing other hook shapes
that can be produced by the process shown in FIG. 4B.
[0035] FIG. 4E are side views of other alternative hook shapes.
[0036] FIG. 5 is a perspective view of an alternative embodiment,
illustrating a tie layer.
[0037] FIG. 6 is a perspective view of an alternative embodiment,
illustrating an adjoining layer.
[0038] FIG. 6A is an enlarged cross-sectional view of a portion of
the embodiment shown in FIG. 6, taken along line 6A-6A.
[0039] FIG. 7 is a diagrammatic view of a process for making a
fastener according to one embodiment.
[0040] FIG. 8 is an enlarged cross-sectional view of a portion of
the embodiment shown in FIG. 1, taken along line 1A-1A, showing cut
line 8A-8A.
[0041] FIG. 8A is an enlarged cross-sectional view of a portion of
the embodiment shown in FIG. 8 after cutting along line 8A-8A.
[0042] FIG. 8B is an enlarged cross-sectional view of another
portion of the embodiment shown in FIG. 8 after cutting along line
8A-8A.
[0043] FIG. 8C shows a prior art fastener with a potentially sharp
edge.
[0044] FIG. 8D shows a top view of a fastener having a non-linear
cut line.
[0045] FIG. 8E shows a top view of fastener having non-linear
lanes.
[0046] FIG. 8F shows a top view of a fastener having lanes of
different widths and functions.
[0047] FIG. 8G is a perspective view of a diaper including the
fastener of FIG. 8F.
[0048] FIG. 9 is a perspective view of a fastener including
height-differentiation.
[0049] FIG. 9A is an enlarged cross-sectional view of a portion of
the fastener shown in FIG. 9, taken along line 9A-9A.
[0050] FIG. 9B shows a portion of the fastener shown in FIG. 9A
after cutting along line 9B-9B.
[0051] FIG. 9C shows a portion of the fastener shown in FIG.
9A.
[0052] FIG. 10 shows an enlarged view of another fastener including
height-differentiation.
[0053] FIG. 11A shows a perspective view of a fastener including
discontinuously molded hooks.
[0054] FIG. 11B shows a perspective view of another fastener
including discontinuously molded hooks.
[0055] FIG. 11C shows a perspective view of another fastener
including discontinuously molded hooks.
[0056] FIG. 12 shows a perspective view of another fastener
including different width lanes.
[0057] FIG. 13 is a perspective view of a fastener with fiber
added.
[0058] FIG. 14A is a perspective view of a fastener including
longitudinal cavities.
[0059] FIG. 14B is a perspective view of another fastener including
longitudinal cavities.
[0060] FIG. 14C shows a perspective view the fastener shown in FIG.
14A after stretching in the machine direction.
[0061] FIG. 14D shows a cross-sectional view of the fastener shown
in FIG. 14C, taken along line 14D-14D.
[0062] FIG. 15 shows a perspective view of a fastener including
foam lanes.
[0063] FIG. 15A is an enlarged cross-sectional view of a portion of
the fastener shown in FIG. 15, taken along line 15A-15A.
[0064] FIG. 15B shows the embodiment illustrated in FIG. 15A, after
cutting along line 15B-15B in FIG. 15A.
[0065] FIG. 16 shows a perspective view of a fastener produced by
stretching a fastener similar to the one shown in FIG. 1 in the
machine direction.
[0066] FIG. 16A shows a perspective view of another fastener
produced by stretching a fastener similar to the one shown in FIG.
1 in the machine direction.
[0067] FIG. 16B shows the fastener of FIG. 16A with peak hooks
engaging loop material.
[0068] FIG. 16C shows the fastener of FIG. 16A with peak and trough
hooks engaging loop material.
[0069] FIG. 16D shows a perspective view of fastener produced by
stretching a fastener similar to the one shown in FIG. 1 in the
machine direction.
[0070] FIG. 16E is a side view of the fastener of FIG. 16D.
[0071] FIG. 16F is a side view that shows the fastener of FIG. 16D
with the hooks engaging a loop material.
[0072] FIG. 16G is a perspective view of a pre-fastener product
that upon stretching can generate the fastener of FIG. 16D.
[0073] FIG. 17 shows a perspective view a fastener resulting from
stretching a fastener similar to the one shown in FIG. 6 in the
machine direction.
[0074] FIG. 18 shows a perspective view of a fastener.
[0075] FIG. 18A shows the fastener of FIG. 18 after stretching in
the cross machine direction.
[0076] FIG. 18B shows the fastener of FIG. 18A after removal of the
adjoining layer.
[0077] FIG. 18C shows a perspective view of a fastener.
[0078] FIG. 18D shows the fastener of FIG. 18C after removal of the
adjoining layer.
DETAILED DESCRIPTION
[0079] FIG. 1 shows a sheet-form fastener 10, including a plurality
of coextruded, side-by-side lanes extending longitudinally in the
machine direction (MD), forming a sheet-form base 12. The
sheet-form base 12 includes lanes 14 of a first polymeric material
disposed in an alternating arrangement between lanes 16 of a
second, different polymeric material. Molded integrally with and
extending outwardly from the sheet-form base 12 in each of the
lanes 16 of the second polymeric material are a plurality of
fastener hooks 18, as shown in detail in FIG. 1A. Fastener products
like these are useful, for example, for creating safe,
skin-friendly products. They are also useful, for example, in
creating better engaging products with greater stretch in the
cross-machine direction (CD). Furthermore, hybrid fasteners with
unusual combinations of properties can be engineered which gives
the end user more design freedom. For example, skin-friendly
products can be created in combination with more aggressive, better
engaging hooks. Polymeric material pairs for lanes 14 and 16 can
include, for example, ABS/polycarbonate,
polypropylene/thermoplastic olefin, ABS (acrylonitrile butadiene
styrene copolymer)/PVC (polyvinyl chloride), polypropylene/styrenic
block copolymer elastomer and polypropylene/polypropylene-based
thermoplastic elastomer vulcanizate. For example, a suitable
material for lane 14 is a polypropylene-based thermoplastic
elastomer vulcanizate (e.g., SANTOPRENE.RTM. elastomer available
from Advanced Elastomer Systems, Akron, Ohio) and a suitable
material for lane 16 is polypropylene. Different colors may be
used, for example, to differentiate the lanes and to denote the
function of each lane. Other additives that improve function or
aesthetics may also be used. For example, glow in the dark
additives, moisture-detecting additives and thermochromic additives
may be used in the sheet-form fastener.
[0080] FIG. 2 shows a sheet-form fastener 11, where all lanes of
the first and second polymeric materials include a plurality of
integrally molded fastener hooks 18 and 20. Thus, hooks 18 are
formed of the second polymeric material, while hooks 20 are formed
of the first polymeric material. The geometry of the hooks can be
different in different lanes. In some cases it may be advantageous
to have specific hooks on specific regions of the fastener to
balance function and safety. For example, aggressive palm-tree
hooks can be used in hard lanes and skin-friendly, flat-topped
hooks in soft lanes. A fastener like this would have high peel
strength, but would also be skin-friendly. This product would be
useful, for example, in a diaper application. Another example would
be to put flat-topped hooks in lanes of a relatively hard material
and palm-tree hooks in the other lane of a relatively hard
material. Fastener such as this would be useful, for example, when
both high shear and high peel are needed. FIG. 2A shows an enlarged
cross-sectional view. Suitable polymers and polymer pairs include
those discussed above with reference to FIG. 1.
[0081] FIG. 3 illustrates a suitable process for forming the
sheet-form fasteners shown in FIG. 1 and FIG. 2. As shown in FIG.
3, extruder 22 and extruder 24 pump their respective polymeric
materials through their respective die connectors 26 and 27 and
through their respective dies 28 and 29, onto rotating roll 30 to
form a web 32 that will define the sheet-form base 12 in the
finished product (e.g., fastener 10 or 11). The die for the first
polymeric material is offset from the die for the second polymeric
material so that when the materials are coextruded, a plurality of
side-by-side lanes are created. The web 32 is pulled through the
nip between roll 30 and a hook-forming roll 34, forming hooks
extending from the web, and stripped from hook-forming roll 34 by
passing the web 32 around a stripping roll 36. As shown in FIG. 3A,
hook-forming roll 34 includes hook-forming cavities 38.
Hook-forming roll 34 is formed of a plurality of etched plates,
e.g., as described in Fischer U.S. Pat. No. 4,775,310, the entire
disclosure of which is incorporated by reference herein. Additional
processing can be applied at nip roll 40. For example, additional
processing may include forming fiber-engaging plate portions at the
distal end of the hooks as described in U.S. Pat. No. 5,953,797,
the disclosure of which is incorporated by reference herein. The
finished sheet-form fastener 10 or 11 is collected at a wind-up
roll 42.
[0082] FIG. 4 illustrates a suitable alternative process for
forming the sheet-form fasteners shown in FIG. 1 and FIG. 2. This
process is similar to that described with reference to FIG. 3,
except the two extruders 22 and 24 are connected via a stream
connector 44. Material passes through stream connector 44 into die
splitter 46. Exiting the die splitter 46 are alternating,
side-by-side lanes which form the web 32. The fastener product is
stripped from hook-forming roll 34 by passing the web 32 between
stripping rolls 35 and 36. FIG. 4A shows a portion of a possible
product resulting from the process. Typically, the base is, for
example, from about 0.001 to about 0.01 inch (about 0.025 mm to
about 0.25 mm) thick, the hooks extend, for example, from about
0.005 to about 0.1 inch (about 0.127 mm to about 2.54 mm) above the
base and the hooks have a density, for example, of about 250 to
about 4000 hooks/inch.sup.2 (about 39 to about 620 hooks/cm.sup.2).
Other suitable processes may be used to form the fastener products.
U.S. Pat. No. 6,432,339, the entire disclosure of which is
incorporated by reference herein, describes another process that
would be suitable if modified to include coextrusion.
[0083] FIG. 4B illustrates another suitable alternative process for
forming the sheet-form fastener shown in FIG. 1 and FIG. 2. In this
process, the extruder 200 injects molten plastic directly onto a
rotating mold roll 202. Multiple lanes of plastic exiting the die
produce multiple lanes in the fastener product (not shown). The
fastener elements extending outwardly from the sheet-form base can
initially be in the form of a lightly crooked hook 208 or a stem
212, as shown in FIG. 4C and FIG. 4D, respectively. After the
sheet-form base is stripped from mold roll 202, the shape of the
engaging fastener elements may be modified with roll 206, to form a
sharply crooked hook 210 or a disk shaped head 214, as shown in
FIG. 4C and FIG. 4D, respectively. FIG. 4E illustrates other
possible engaging fastener element shapes.
[0084] We define different polymeric materials to mean polymeric
materials of different chemical composition or polymeric materials
of nearly the same chemical composition, but with different
physical properties. Differing physical properties may arise, for
example, from differing polymer chain lengths, differing
distribution of chain lengths, microstructure of the polymer,
additives, etc. Thus, different polymeric materials not only
include polypropylene and a polypropylene-based thermoplastic
elastomer vulcanizate (e.g., SANTOPRENE.RTM. elastomer), but also
two different melt flow grades of polypropylene.
[0085] Adhesion of the alternating lanes 14 and 16 may become an
issue if the materials that make up lanes 14 and 16 do not adhere
well to each other. In this case, compatibility agents may be added
to the first polymeric material, the second polymeric material or
to both the first and second polymeric materials. Compatibility
agents can increase the bond strength of the side-by-side lanes
and, as a result, can prevent the lanes from separating. For
example, a lane of nylon-12 can be made more compatible with a lane
of a styrenic elastomer copolymer by adding approximately 10% of a
polyether-based polyurethane elastomer to the styrenic elastomer
copolymer.
[0086] FIG. 5 shows an alternative embodiment in which a tie layer
is provided to bond lanes 14 and 16. Sheet-form fastener 50
includes a plurality of coextruded, side-by-side lanes 14 and 16
extending longitudinally in the machine direction. A tie layer 52
is interposed between lanes 14 and 16. The polymeric material in
tie layer 52 bonds well to both of the lanes 14 and 16 and, thus,
"bridges" lanes 14 and 16. For example, the tie layer can be a
functionalized polyolefin (e.g., maleic anhydride functionalized
polyolefin). The width of tie layer 52 in the cross-machine
direction (CD) is, for example, from about 0.0005 to about 0.005
inch (about 0.013 mm to about 0.13 mm) or more.
[0087] FIG. 6 shows another embodiment in which a base layer is
provided to bond lanes 14 and 16. The base layer can be woven,
non-woven, foam or films. Fastener 54 includes a plurality of
coextruded, side-by-side lanes 14 and 16 extending longitudinally
in the machine direction. Lanes 14 and 16 are adjoined by a base
layer 56 of polymeric material extending longitudinally in the
machine direction under lanes 14 and 16, forming the sheet-form
base 13. U.S. Pat. Nos. 5,518,795 and 5,744,080, the entire
contents of which are incorporated by reference herein, describes
the preparation of laminate hook fasteners having a similar base
layer. FIG. 6A shows an enlarged cross-sectional view. The
polymeric material in base layer 56 bonds well to both of the lanes
14 and 16. The thickness of base layer 56 is, for example, from
about 0.00001 to about 0.100 inch (about 0.00025 to about 2.5 mm)
or more.
[0088] FIG. 7 illustrates a suitable process for forming the
fastener shown in FIG. 5. This process is similar to the process
shown in FIG. 4, except, in addition to the extruders 22 and 24,
the process utilizes a third extruder 58. Extruder 58 pumps the
material of tie layer 52 through stream connector 60. All material
streams come together at die splitter 62, creating a web 64,
including tie layer 52 and alternating lanes 14 and 16. The web 64
is pulled through the nip between roll 30 and hook-forming roll 34,
forming hooks extending from the web (not shown), and is stripped
from 34 by passing the web 64 between stripping rolls 35 and 36.
Additional post-processing techniques may be applied to the product
exiting the stripping rolls 35 and 36.
[0089] FIG. 7 also illustrates a suitable process for forming the
product shown in FIG. 6. The setup for this process is similar to
that process shown in FIG. 4, except, in addition to the extruders
22 and 24, the process utilizes a third extruder 58. In this case,
extruder 58 pumps base layer 56 through stream connector 60. All
material streams come together at die splitter 63, creating web 65,
including under base layer 56 and alternating lanes 14 and 16. The
web 65 is pulled through the nip between roll 30 and hook-forming
roll 34, forming hooks extending from the web (not shown), and is
stripped from 34 by passing the web 65 between stripping rolls 35
and 36.
[0090] FIG. 8 is a cross-sectional view of a portion of the
sheet-form fastener 10 shown in FIG. 1A, with a cut line 8A-8A,
indicating where the fastener 10 would be slit to form multiple
fasteners. The polymeric material that forms lanes 14 is a softer
material than the polymeric material that forms lanes 16, and thus
the edges of the fastener tapes will be soft and skin-friendly.
FIG. 8A and FIG. 8B show soft-edge sheet-form fasteners 68 and 69
that are derived from sheet-form fastener 10 by cutting along line
8A-8A. FIG. 8C shows a prior art sheet-form fastener 72, with a
relatively hard edge as detected by the human finger 70. The cut
shown by line 8A-8A can be made by a variety of means known in the
art. Examples include, but are not limited to, die cutting, laser
cutting, knife cutting, ultra-sonic cutting, air knife, water
knife, split line formed by polymers having low adhesion and
built-in, perforated split lines. FIG. 8D shows a top view of a
diaper tab 74, cut in a non-linear fashion along a lane 14 of the
relatively soft polymeric material, exposing a soft edge. Lanes 16
of the diaper tab 74 do not need to have the same type of hook on
each lane. For example, "aggressive" hooks may be used in the lanes
near the outer edge 75 of the diaper tab to create a product with
high shear performance and high peel strength, while maintaining a
soft edge. When lanes 14 are made of a thermoplastic elastomer, the
improved stretch in the cross-machine direction can make diaper tab
74 engage better with complementary loop material (not shown) and
can make it less likely to be inadvertently removed. A suitable
polymeric material is a thermoplastic elastomer vulcanizate (e.g.,
SANTOPRENE.RTM. elastomer). The hardness of lanes 14 may be, for
example, from about 45 shore A to about 75 shore D. To make
material more sticky, tackifying agents may be used.
[0091] FIG. 8E shows a top view of a portion of a diaper tab 79,
with non-linear, alternating lanes. Lanes 14 are formed from a
relatively soft material and lanes 16 are formed from a relatively
hard material. The sheet-form fastener shown in FIG. 8E can be made
by the process shown in FIG. 3A, using traversing dies. Preparing a
diaper tab in this manner creates a soft-edge fastener and can
eliminate the need for cutting in the machine direction (MD).
[0092] FIG. 8F shows a top view of a diaper tab 81, cut in a
non-linear fashion along lane 14 of a relatively soft, tacky
polymeric material, exposing a soft-edge. In addition, this tab 81
has a wider lane 80 of the relatively tacky, soft material,
disposed between two lanes 16, each without hooks. This wider lane
80 can, for example, add additional stretch for better engagement.
Wide lane 80 can come into contact with the skin of a baby and can
act as an additional anchoring point. FIG. 8G shows diaper tab 81
attached to diaper 250. Diaper tab 81 is fastened to complementary
loop material 251 to close the diaper 250.
[0093] FIG. 9 shows yet another embodiment. In this embodiment,
sheet-form fastener 76 includes a sheet-form base 12, formed from
alternating lanes 14 and 16. The polymeric material that forms
lanes 14 is softer than the polymeric material that forms lanes 16.
Fastener hooks 18 extend outwardly from the harder polymeric
material lanes 16. Suitable materials for lanes 14 may include
thermoplastic elastomers (e.g., SANTOPRENE.RTM. elastomer). In
addition to the lanes 14 being formed from a softer material than
the lanes 16, the lanes 14 and 16 are height-differentiated, i.e.,
lanes 14 have height H1 that is greater than height H2 of lanes 16.
Generally, height-differentiation can help "shroud" or hide the
hooks 18. Height differences in the fastener product can be created
by making the appropriate complementary mold roll 34. FIG. 9A shows
a cross-sectional view of the sheet-form fastener 76 shown in FIG.
9. Cutting the fastener along line 9B-9B results in
height-differentiated, soft-edge fasteners 77 and 78, shown in FIG.
9B and FIG. 9C, respectively. Height-differentiation provides, for
example, additional protection of the user's skin against the
relatively hard hooks 18 extending outwardly from lanes 16. Thus, a
human finger moving gently across the sheet-form fastener 76 in the
cross-machine (CD) direction will be more likely to contact the
soft material of lanes 14, rather than the relatively hard hooks
18. Of course, a few hooks may extend above the height of the soft
lanes 14 without significantly reducing the softness and safety of
the overall product. Lanes 14 of the relatively soft material may
also include hooks (not shown), providing additional
height-differentiation and, therefore, additional "soft-touch" and
safety. The height-differentiation should not be so large that the
hooks 18 cannot engage loops of a female fastener component (not
shown) to form a complete hook and loop fastener.
[0094] FIG. 10 shows a fastener 73 that features lanes 16 of a
relatively hard material with hooks 18 extending outwardly and
lanes 14 of a relatively soft material with hooks 20 extending
outwardly. The hooks 18 and 20 are height-differentiated, i.e., the
distal ends of the hooks 20 extending outwardly from the lanes
formed of the softer material 14 are generally higher than most of
the distal ends of the hooks extending outwardly from lanes 16. A
human finger 70 moving gently across such a sheet-form fastener in
the cross-machine (CD) direction will be more likely to contact the
soft hooks 20 extending outwardly from lanes 14, rather than the
shorter, relatively hard hooks extending outwardly from lanes 16.
This embodiment provides additional skin-friendliness and safety.
The softer hooks 20 may or may not serve the purpose of engaging a
corresponding female loop component. For example, the hooks 20 may
be replaced by non-engageable stems (not shown). It is generally
important that the height-differentiation not be so large that the
soft hooks 20 prevent the harder hooks 18 from engaging the loops
of a female component (not shown) to form a complete hook and loop
fastener.
[0095] FIG. 11A shows a perspective view of a sheet-form fastener
71 having hooks 18 that are discontinuously molded on lanes 16. By
discontinuously, we mean that there are relatively large regions 82
where hooks are absent. Regions of discontinuity may, for example,
improve safety by reducing the number of relatively hard hooks. The
length of the regions of discontinuity 82, as measured
longitudinally in the machine direction (MD) may be, for example,
from about 0.005 to about 10 inches (about 0.13 mm to about 254
mm), depending upon the application.
[0096] FIG. 11B shows a perspective view of a sheet-form fastener
84 similar to that shown in FIG. 11A, but with hooks 20 extending
from lanes 14. Hooks 20 may be discontinuously molded on lanes 14
(not shown).
[0097] FIG. 11C shows a perspective view of a sheet-form fastener
88 in which lanes 14 and lanes 16 are height-differentiated and the
hooks 18 are discontinuously molded on lanes 16.
[0098] FIG. 12 shows a fastener 94 having a greater degree of
stretch as a result of increasing the width of relatively soft
lanes 14 relative to the width of lanes 16. A greater degree of
stretch may, for example, increase engagement of the hooks with a
loop material (not shown) and may, for example, increase safety and
skin-friendliness. The softer the material used for lanes 14, the
greater the degree of stretch imparted to fastener 94.
[0099] FIG. 13 shows a sheet-form fastener 112 in which the
polymeric material that forms lanes 14 is a softer and tackier
material than the polymeric material that forms lanes 16, and a
fiber 114 is adhered to the tacky lanes 14. Bonding can be, for
example, the result of the inherent tackiness of the lane 14 or can
be achieved or enhanced by, for example, the addition of other
resinous materials such as curable adhesive. If additional resinous
material is used to bond the fiber to the fastener, the resinous
material may be cured using UV light, heat or other techniques. The
fiber 114 cause the lanes to be height-differentiated resulting in
a skin-friendly soft touch fastener product. The fiber can be
cotton or fine denier polypropylene. The bonding agents may be, for
example, acrylic or polyurethane.
[0100] FIG. 14A shows a sheet-form fastener 116 having cavities 120
that extend longitudinally through lanes 16. The cavities may be
un-filled (hollow) or they may be filled with a material.
Similarly, FIG. 14B shows a sheet-form fastener 118 with cavities
120 and 122 that extend longitudinally through lanes 14 and 16,
respectively. Some longitudinal cavities may be filled, while some
longitudinal cavities may be un-filled. If the longitudinal
cavities are filled, fillers may include, for example, shape memory
polymers. For example, the shape memory polymer may be DIAPLEX.RTM.
polyurethane shape memory polymer. The cavities may also be filled
with, for example, metal wire for bendability and rigidity,
electrical conductors and optical fibers.
[0101] FIG. 14 C shows a sheet-form fastener 124, resulting from
post stretching after forming hooks 18 in the machine direction.
Various structures with different three-dimensional shapes are
possible, depending upon the materials used for lanes 14 and 16 and
depending upon the material used (if any) for filling the
longitudinal cavities 120. Such a structure can allow for a more
skin-friendly hook fastener because many of the hooks are
"shrouded" in the three dimensional, rippled structure of the
stretched hook fastener. Simply pushing the structure flat exposes
more hooks to engage the loops of a loop component (not shown).
FIG. 14D shows a cross-sectional view taken in the machine
direction, along line 14D-14D of FIG. 14C. Hooks 18 form complex
angles due to the rippled shape of the underlying structure. These
complex angles can allow for, for example, better engagement,
better shear strength, improved safety and "soft touch."
[0102] FIG. 15 shows a sheet-form fastener 96, including a
plurality of coextruded, alternating, side-by-side lanes extending
longitudinally in the machine direction (MD), forming a
sheet-form-base 98. The sheet-form base includes a lane 100 of a
polymeric material and a lane 102 of polymeric foam. A plurality of
molded fastener elements 104 extend outwardly from, and integral
with, the lanes 100. Lanes 100 and lanes 102 are
height-differentiated, as discussed above. In some instances, lane
100 is made of a thermoplastic polymer and lane 102 is made of a
foamed thermoplastic polymer. In other instances, lane 100 is a
non-elastomeric thermoplastic polymer, e.g., polypropylene, and
lane 102 is made of a foamed elastic polymer, e.g. a
polypropylene-based thermoplastic elastomer vulcanizate (e.g.,
SANTOPRENE.RTM. elastomers).
[0103] Lane 102 may be foamed by a variety of methods, including
using, for example, a chemical foaming agent (e.g., HYDROCEROL.RTM.
chemical foaming agent available from Clariant Corporation, Holden,
Mass.) or by injecting a gas (e.g., carbon dioxide, nitrogen or
others) into the plastic that is to form lane 102. FIG. 15A shows
an enlarged cross-sectional view of a portion of the sheet-form
fastener 96, taken along line 15A-15A. In this particular case, a
height-differentiated fastener is shown, where the height of lane
102, with foam voids 106, is greater than the height of the hooks
104 extending outwardly from lane 100. The fastener shown in FIG.
15A may have lanes of the same height and/or some hooks may be
molded in lanes 102. As discussed above, adhesion between lanes 100
and 102 may be optimized by using a tie layer. Also, an adjoining
layer may be bonded below lanes 100 and 102 (not shown). FIG. 15B
shows a soft edge fastener 108, formed from cutting fastener 96
along line 15B-15B.
[0104] Other methods of forming sheet-form fastener 96 may be used.
For example, lanes 100 with hooks 104 and lanes 102 may be formed
in a separate step and bonded together later in the process. Using
this method, lane 102 may be, for example, formed of a foamed
thermoset plastic (e.g., polyurethane) instead of a thermoplastic.
Likewise, lane 100 may be formed of a thermoset. Thermosets may be
advantageous when, for example, the products are used in a harsh
environment.
[0105] FIG. 16 shows a sheet-form fastener 128 having a three
dimensional, ripple-type structure that can result from stretching
fastener 10 shown in FIG. 1 in the machine direction. The three
dimensional, ripple-type structure results from the differing
physical properties of the materials that make up lanes 14 and 16
and their different tendencies to return to their initial
(un-stretched) state. In some instances, the thickness of the
sheet-form base changes during stretching in a non-uniform way,
resulting in "kinks" 129 in the ripple structure. In other
instances, the thickness of the base changes in a more uniform way,
resulting in the structure shown in FIG. 16A and discussed below.
Such a ripple-type structure may allow for, for example, a more
skin-friendly hook fastener because many of the hooks are
"shrouded" in the three dimensional, rippled structure of the
stretched hook fastener.
[0106] FIG. 16A shows a three dimensional, ripple-type fastener
150, with alternating lanes 14 and 16. Hooks 152 extend from peaks
156 in lanes 16, while hooks 154 extend from troughs 158 in lanes
16. This three dimensional, ripple-type structure can result from,
for example, stretching fastener 10 shown in FIG. 1 in the machine
direction. In this instance, the thickness of the base changed in a
uniform way upon stretching. FIG. 16B shows the fastener of FIG.
16A engaging a loop material 160 connected to a support base 162
and illustrates that only hooks 152 on the peaks 156 of the
fastener engage the loop material in response to light force. FIG.
16C illustrates that when more force is applied, the hooks 154 in
the troughs 158 engage as well. FIG. 16C further illustrates
rippling of the loop support structure 162 as a result of the
differential forces applied to it by the rippled fastener
below.
[0107] FIG. 16D shows a three-dimensional, ripple-type fastener 163
with hooks 154 only in troughs 158. FIG. 16E illustrates that a
hook 154 in a trough 158 is below the level of the peak 156,
resulting in a "soft touch" fastener. FIG. 16F illustrates that
with force, hooks 154 engage loop material 160 to form a hook and
loop fastener. FIG. 16G shows a precursor 166 to the fastener shown
in FIG. 16D. This precursor 166 contains thick regions 165 with
hooks 154 extending from these regions and thin regions 164 with no
hooks. Upon stretching, a fastener similar to the one shown is FIG.
16 or FIG. 16A is produced.
[0108] FIG. 17 shows a possible three dimensional, ripple-type
structure 132 resulting from stretching the sheet-form fastener 54
with bottom layer 56 of FIG. 6 in the machine direction.
[0109] FIG. 18 shows a sheet-form fastener 139, including lanes 14
and 16 and base layer 56, the base layer 56 being at least
extensible. Lanes 16 have molded hooks 18 extending outwardly.
Sheet-form fastener 140 shown in FIG. 18A is derived from
sheet-form fastener 139 by stretching fastener 139 in, for example,
the cross-machine direction (CD). Cross-machine stretching is
described by Buzzell, et al. in U.S. Pat. No. 6,035,498, the entire
disclosure of which is incorporated by reference. Adhesion between
lanes 14 and 16 is relatively poor at the interface 136 between the
lanes. Upon stretching, lanes 14 and 16 separate at interface 136,
but remain attached to adjoining layer 56. Due to separation, the
interface 136 becomes gap 138 (FIG. 18A). In some instances,
structure 140 may curl (not shown), forming a three-dimensional
structure. Materials for lanes 14 and 16 are chosen to allow the
lanes to separate at interface 136 during CD stretching. Thus,
generally the two materials are relatively incompatible. Adhesion
of lanes 14 and 16 to bottom layer 56 should be good enough so that
the lanes of 14 and 16 do not separate from the adjoining layer 56.
The structure 140 allows for, for example, greater flexibility of
the fastener product, especially in the out of plane directions
141. Greater flexibility allows for, for example, good safety and
skin-friendliness. Materials that are normally compatible may be
made incompatible by additives. Examples of such additives are
TEFLON.RTM. fluoropolymer and a relatively high loading of clay
(e.g., 25%).
[0110] FIG. 18B shows that removal of the bottom layer 56 from
structure 140 yields discrete elements 171 and 172. This could be
an efficient method of preparing several different fastener
products on one manufacturing line.
[0111] FIG. 18C shows a fastener product 176, including, in
addition to lanes 14 and 16, lanes 178, 180 and 184. A bottom layer
56 is below the lanes. Upon stretching lanes 14 and 16 separate
from one another, but remain attached to the bottom layer 56 (not
shown). Upon removal of the bottom layer 56, discrete units 188,
lane 14 and 190 result as shown in FIG. 18D.
[0112] A number of embodiments of the invention have been
described. For example, some of the lanes may be made of a
cross-linkable material. Nevertheless, it will be understood that
various modifications may be made without departing from the spirit
and scope of the invention Accordingly, other embodiments are
within the scope of the following claims.
* * * * *