U.S. patent application number 13/078248 was filed with the patent office on 2011-10-20 for methods of forming composite materials.
This patent application is currently assigned to VELCRO INDUSTRIES B.V.. Invention is credited to William H. Shepard.
Application Number | 20110253289 13/078248 |
Document ID | / |
Family ID | 44065835 |
Filed Date | 2011-10-20 |
United States Patent
Application |
20110253289 |
Kind Code |
A1 |
Shepard; William H. |
October 20, 2011 |
METHODS OF FORMING COMPOSITE MATERIALS
Abstract
A method of forming a substantially air-impermeable composite
material includes introducing a sheet-form film and a loop material
into a nip formed between a first roll and a second roll,
introducing molten resin into the nip between the film and the loop
material, and allowing the molten resin to cool so that the film
becomes attached to the loop material by the cooled resin.
Inventors: |
Shepard; William H.;
(Amherst, NH) |
Assignee: |
VELCRO INDUSTRIES B.V.
Curacao
AN
|
Family ID: |
44065835 |
Appl. No.: |
13/078248 |
Filed: |
April 1, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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61324545 |
Apr 15, 2010 |
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Current U.S.
Class: |
156/66 |
Current CPC
Class: |
B29C 48/0021 20190201;
B29L 2031/738 20130101; B29C 66/53262 20130101; B32B 37/153
20130101; B29C 66/929 20130101; B32B 2323/04 20130101; B29C
66/73186 20130101; B29C 66/1122 20130101; B29C 66/7294 20130101;
B29C 66/91645 20130101; B29C 66/919 20130101; B29C 48/08 20190201;
B29C 66/73115 20130101; B29C 66/348 20130101; B32B 2309/14
20130101; B29C 48/305 20190201; B29C 66/83415 20130101; B29C 59/04
20130101; B29C 2793/009 20130101; B32B 2307/542 20130101; B29C
43/222 20130101; B29C 66/71 20130101; B29L 2031/753 20130101; B29C
66/3494 20130101; B32B 2309/105 20130101; B29C 66/73116 20130101;
B29C 66/73921 20130101; B29K 2023/06 20130101; A61B 5/02233
20130101; B29C 66/4322 20130101; B32B 38/06 20130101; B29C 66/7352
20130101; B29C 66/83221 20130101; B32B 37/203 20130101; B29C
66/92211 20130101; B32B 2037/148 20130101; B29C 65/02 20130101;
B29K 2105/0088 20130101; B29L 2031/7148 20130101; B32B 2309/02
20130101; B29C 65/405 20130101; B29C 66/83413 20130101; B29L
2031/729 20130101; B29C 66/431 20130101; B29C 66/91421 20130101;
B32B 2307/718 20130101; B29C 66/45 20130101; B32B 2307/546
20130101; B29C 43/28 20130101; B29C 66/69 20130101; B32B 2323/10
20130101; A44B 18/0057 20130101; B29C 48/0011 20190201; B32B
2305/18 20130101; B32B 2307/7242 20130101; B32B 2309/12 20130101;
B29C 66/71 20130101; B29K 2023/12 20130101; B29C 66/71 20130101;
B29K 2023/04 20130101; B29C 66/71 20130101; B29K 2023/10 20130101;
B29C 66/71 20130101; B29K 2077/00 20130101; B29C 66/71 20130101;
B29K 2023/06 20130101 |
Class at
Publication: |
156/66 |
International
Class: |
A41H 37/02 20060101
A41H037/02 |
Claims
1. A method of forming a composite material, the method comprising:
introducing a sheet-form film and a hook-engageable material into a
nip formed between a first roll and a second roll; introducing
molten resin into the nip between the film and the hook-engageable
material; and allowing the molten resin to cool so that the film
becomes attached to the hook-engageable material by the cooled
resin, wherein each of the film, the hook-engageable material, and
the molten resin includes at least about 85 percent by weight of a
first polymer.
2. The method of claim 1, wherein the composite material is
substantially air-impermeable.
3. (canceled)
4. The method of claim 1, wherein fibers extending from a surface
of the hook-engageable material are capable of engaging hooks of
hook fasteners after the film is attached to the hook-engageable
material by the cooled resin.
5. The method of claim 1, wherein the first polymer is
polypropylene.
6. The method of claim 5, wherein the film and the hook-engageable
material consist essentially of polypropylene.
7. The method of claim 6, wherein the molten resin is at least
about 90 percent by weight polypropylene.
8. The method of claim 7, wherein the molten resin further
comprises polyethylene.
9. The method of claim 1, wherein the hook-engageable material
comprises a 17 grams per square meter spunbond polypropylene
substrate through which a plurality of loop shaped staple fibers
extend.
10. The method of claim 1, wherein the hook-engageable material
comprises a 30 grams per square meter SMS polypropylene substrate
through which a plurality of loop shaped staple fibers extend.
11. The method of claim 1, wherein the molten resin introduced into
the nip has a thickness of about one mil, the film has a thickness
of about three mils, and the hook-engageable material has a weight
of about 1.3 to about 2.0 osy.
12. (canceled)
13. The method of claim 1, wherein the molten resin is at a
temperature of at least about 500 degrees Fahrenheit when
introduced into the nip.
14-15. (canceled)
16. The method of claim 1, wherein the film is a cast film.
17. The method of claim 1, wherein the molten resin is introduced
into the nip in a manner such that the molten resin contacts the
film and the hook-engageable material at substantially the same
time.
18. The method of claim 1, wherein the molten resin is introduced
into the nip by applying the molten resin to the hook-engageable
material and rotating the first and second rolls to carry the film,
the hook-engageable material, and the molten resin into the
nip.
19. The method of claim 1, wherein the molten resin is introduced
into the nip by applying the molten resin to the film and rotating
the first and second rolls to carry the film, the hook-engageable
material, and the molten resin into the nip.
20. The method of claim 1, wherein at least one of the first and
second rolls is chilled to facilitate cooling of the molten
resin.
21. (canceled)
22. The method of claim 1, further comprising embossing the
composite material.
23. The method of claim 22, wherein embossing the composite
material comprises passing the composite material between an
embossing roll and a backing roll, the embossing roll have a
plurality of raised features that compress the composite material
between the embossing roll and the backing roll.
24. The method of claim 23, wherein the embossing roll is a heated
roll.
25. A method of forming a composite material, the method
comprising: introducing a sheet-form film and a hook-engageable
material into a nip formed between a first roll and a second roll;
introducing molten resin into the nip between the film and the
hook-engageable material; and allowing the molten resin to cool so
that the film becomes attached to the hook-engageable material by
the cooled resin, wherein each of the film, the hook-engageable
material, and the molten resin includes at least about 90 percent
by weight of a first polymer, the composite material is
substantially air-impermeable, and fibers extending from a surface
of the hook-engageable material are capable of engaging hooks of
hook fasteners after the film is attached to the hook-engageable
material by the cooled resin.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 61/324,545, filed on Apr. 15, 2010, which is
incorporated by reference herein.
TECHNICAL FIELD
[0002] This invention relates to methods of forming composite
materials.
BACKGROUND
[0003] Multi-layered composite materials are used for various
different types of applications. In certain cases, such composite
materials are constructed in a way to make the composite materials
substantially liquid-impermeable and/or air-impermeable.
Liquid-impermeable and/or air-impermeable composite materials can
be used in products in which it is useful to prevent liquid and/or
air from escaping from the product during use.
SUMMARY
[0004] In one aspect of the invention, a method of forming a
composite material includes introducing a sheet-form film and a
hook-engageable material into a nip formed between a first roll and
a second roll, introducing molten resin into the nip between the
film and the hook-engageable material, and allowing the molten
resin to cool so that the film becomes attached to the
hook-engageable material by the cooled resin. Each of the film, the
hook-engageable material, and the molten resin includes at least
about 85 percent by weight of a first polymer.
[0005] In another aspect of the invention, a method of forming a
composite material includes introducing a sheet-form film and a
hook-engageable material into a nip formed between a first roll and
a second roll, introducing molten resin into the nip between the
film and the hook-engageable material, and allowing the molten
resin to cool so that the film becomes attached to the
hook-engageable material by the cooled resin. Each of the film, the
hook-engageable material, and the molten resin includes at least
about 90 percent by weight of a first polymer, the composite
material is substantially air-impermeable, and fibers extending
from a surface of the hook-engageable material are capable of
engaging hooks of hook fasteners after the film is attached to the
hook-engageable material by the cooled resin.
[0006] Embodiments can include one or more of the following
features.
[0007] In some embodiments, the composite material is substantially
air-impermeable.
[0008] In certain embodiments, the composite material has an
air-permeability of 0 cm.sup.3/s/cm2.
[0009] In some embodiments, fibers extending from a surface of the
hook-engageable material are capable of engaging hooks of hook
fasteners after the film is attached to the hook-engageable
material by the cooled resin.
[0010] In certain embodiments, the first polymer is
polypropylene.
[0011] In some embodiments, the film and the hook-engageable
material consist essentially of polypropylene.
[0012] In certain embodiments, the molten resin is at least about
90 percent by weight polypropylene.
[0013] In some embodiments, the molten resin further includes
polyethylene.
[0014] In certain embodiments, the hook-engageable material
includes a 17 grams per square meter spunbond polypropylene
substrate through which a plurality of loop shaped staple fibers
extend.
[0015] In some embodiments, the hook-engageable material includes a
30 grams per square meter SMS polypropylene substrate through which
a plurality of loop shaped staple fibers extend.
[0016] In certain embodiments, the molten resin introduced into the
nip has a thickness of about one mil, the film has a thickness of
about three mils, and the hook-engageable material has a weight of
about 1.3 to about 2.0 osy.
[0017] In some embodiments, the hook-engageable material has a
basis weight of about 1.3 to about 1.6 osy.
[0018] In certain embodiments, the molten resin is at a temperature
of at least about 500 degrees Fahrenheit (e.g., about 550 degrees
Fahrenheit to about 600 degrees Fahrenheit, about 580 degrees
Fahrenheit) when introduced into the nip.
[0019] In some embodiments, the film is a cast film.
[0020] In certain embodiments, the molten resin is introduced into
the nip in a manner such that the molten resin contacts the film
and the hook-engageable material at substantially the same
time.
[0021] In some embodiments, the molten resin is introduced into the
nip by applying the molten resin to the hook-engageable material
and rotating the first and second rolls to carry the film, the
hook-engageable material, and the molten resin into the nip.
[0022] In certain embodiments, the molten resin is introduced into
the nip by applying the molten resin to the film and rotating the
first and second rolls to carry the film, the hook-engageable
material, and the molten resin into the nip.
[0023] In some embodiments, at least one of the first and second
rolls is chilled to facilitate cooling of the molten resin.
[0024] In certain embodiments, both of the first and second rolls
are chilled.
[0025] In some embodiments, the method further includes embossing
the composite material.
[0026] In certain embodiments, embossing the composite material
includes passing the composite material between an embossing roll
and a backing roll. The embossing roll has a plurality of raised
features that compress the composite material between the embossing
roll and the backing roll.
[0027] In some embodiments, the embossing roll is a heated
roll.
[0028] Embodiments can include one or more of the following
advantages.
[0029] In certain embodiments, the composite materials formed using
the various methods described herein are formed substantially
entirely of a single type of polymer (e.g., polypropylene). Each
component or layer of the composite material can, for example,
include at least about 85 percent by weight (e.g., at least about
90 percent by weight, at least about 95 percent by weight) of the
single type of polymer. Such composite materials can, for example,
be easily recycled. In addition, such composite materials can
provide improved weldability. For example, because the various
components of the composite material are formed of substantially
entirely the same type of material, it is relatively easy to
thermally bond those components together.
[0030] In some embodiments, the composite materials formed using
the various methods described herein are air-impermeable. As a
result, the composite materials can be used to form inflatable
bladders (e.g., inflatable bladders used in medical products, such
as inflatable compression devices). The composite materials can
alternatively or additionally be substantially liquid-impermeable,
which allows the composite materials to be used as liquid barriers.
Such liquid barriers can be advantageously used in products, such
as medical cold wraps, where it is desirable to prevent a freezable
cooling solution or water from melting and leaking out of the
product.
[0031] In certain embodiments, the composite materials formed using
the various methods described herein include a hook-engageable
surface. In such embodiments, the composite materials can be used
to form products that benefit from being releasably fastened.
Examples of such products include medical wraps and compression
devices.
[0032] In some embodiments, the composite material is embossed
before being formed into or incorporated into a product. It has
been found that the embossed regions of the composite material
facilitate folding or bending of the composite material. When
inflatable products, such as medical compression devices, are
formed using the embossed composite material, the noise associated
with inflating the product can be reduced as a result of the
embossed composite material. For example, crinkling noises often
associated with the inflation of relatively thin materials can be
reduced due to the facilitated folding or bending of the composite
material along the embossed regions. This can be particularly
advantageous for blood pressure cuffs used with blood pressure
monitoring devices that detect audible signals while inflating and
deflating the cuff.
[0033] Certain methods described herein can be used to rapidly and
efficiently produce composite materials that are formed
substantially entirely of a single type of polymer (e.g.,
polypropylene), that are substantially air-impermeable and/or
liquid impermeable, and that include a hook-engageable surface. It
has been discovered, for example, that sufficient amounts of molten
resin polymer can be applied between a polymeric film and polymeric
loop material to achieve a substantially air-impermeable and/or
liquid-impermeable composite material without destroying the
functionality of the loops of the loop material, even when the
molten resin and the loop material are formed substantially
entirely of the same type of polymeric material (e.g., even when at
least about 85 percent by weight of the molten resin and at least
about 85 percent by weight of the loop material is the same type of
polymeric material, such as polypropylene) and thus have similar
melting temperatures.
[0034] Other aspects, features, and advantages will be apparent
from the description and drawings, and from the claims.
DESCRIPTION OF DRAWINGS
[0035] FIG. 1 is a schematic of a lamination system during use to
form a substantially air-impermeable composite material.
[0036] FIG. 2 is an enlarged view of region 2 in FIG. 1, showing
loops, which are capable of engaging hooks of hook fastener
products, extending from a loop material layer of the composite
material.
[0037] FIG. 3 is an enlarged view of region 3 in FIG. 1, showing
the multiple bonded layers of the composite material.
[0038] FIGS. 4 and 5 are front and side views, respectively, of a
blood pressure cuff manufactured in part from substantially
air-impermeable composite material formed using the method
schematically illustrated in FIG. 1.
[0039] FIG. 6 illustrates the blood pressure cuff of FIGS. 4 and 5
during use.
[0040] FIG. 7 illustrates a method of manufacturing multiple blood
pressure cuffs of the type shown in FIGS. 4-6 by folding a single
sheet of the composite material of FIG. 1 and then welding
overlapping regions of the folded sheet together.
[0041] FIG. 8 illustrates an alternative method of manufacturing
multiple blood pressure cuffs of the type shown in FIGS. 4-6 by
welding two sheets of the composite material of FIG. 1
together.
[0042] FIG. 9 is a front view of a sequential compression device
manufactured in part from substantially air-impermeable composite
material formed using the method schematically illustrated in FIG.
1.
[0043] FIG. 10 illustrates the sequential compression device of
FIG. 9 configured for use.
[0044] FIG. 11 is a perspective view of a urinary drain bag.
DETAILED DESCRIPTION
[0045] FIG. 1 schematically illustrates a lamination system 100
during use. As shown in FIG. 1, system 100 includes a pressure roll
102 and two backing rolls 104 and 106. Rolls 102 and 104 are
positioned adjacent one another and form a nip 108 between their
peripheral surfaces. Pressure roll 102 and backing roll 104 are
connected to motors that are configured to rotate rolls 102 and 104
in opposite directions during use, as indicated by arrows 110 and
112. When operated in this manner, pressure roll 102 and backing
roll 104 can cooperate to draw material (e.g., film, loop material,
and/or resin) through nip 108 while applying pressure to the
material passing through nip 108.
[0046] Backing roll 106 is positioned adjacent pressure roll 102 on
the opposite side of pressure roll 102 from backing roll 104.
Backing roll 106 is equipped with bearings such that backing roll
106 can rotate in response to the rotation of pressure roll 102.
Backing roll 106 serves as a support for pressure roll 102 to help
prevent pressure roll 102 from bowing outward as a result of
increased pressure within nip 108. As a result, backing roll 106
helps to ensure that a desired uniform pressure is maintained in
nip 108 during use.
[0047] Pressure roll 102 is a steel roll coated with
polytetrafluoroethylene (PTFE). Typically, pressure roll 102 has a
diameter of about 18 inches to about 24 inches. Backing rolls 104
and 106 are formed of steel and are uncoated. Each of rolls 102,
104, and 106 is capable of being chilled. For example, these rolls
can included cooling passages through which a cooling liquid, such
as water, can travel during use. The cooling liquid can be forced
through the passages continuously during use to maintain the rolls
at a reduced temperature.
[0048] A slot die extruder 114 is positioned above nip 108.
Extruder 114 includes a die 115 through which molten resin is
extruded during use. Extruder 114 is adjustable both vertically and
horizontally such that extruder die 115 can be positioned at
multiple different locations relative to nip 108.
[0049] Two rotatable shafts 116 and 118 are positioned above rolls
102 and 104. Rotatable shafts 116 and 118 are connected to motors
that can drive shafts 116 and 118 at multiple different rotational
speeds. As shown in FIG. 1, shaft 116 is configured such that a
film roll 128 can be loaded thereon, and shaft 118 is configured
such that a loop material roll 130 can be loaded thereon. As
described below, during use, film 122 from film roll 128 and loop
material 124 from loop material roll 130 can be introduced into nip
108 by rotating shafts 116 and 118, causing the rolls 128, 130 to
unwind.
[0050] System 100 also includes another rotatable shaft referred to
as a winder 120. Winder 120, like shafts 116 and 118, is connected
to a motor that can drive winder 120 at multiple different
rotational speeds. As described below, a substantially
air-impermeable composite material 121 exiting nip 108 can be wound
onto winder 120 for storage, shipment, or further processing by
rotating winder 120. The rotational speeds of rolls 102, 104, 106,
shafts 116, 118, and winder 120 can be controlled so that a desired
tension is applied to the composite material exiting nip 108 and
being wound onto winder 120.
[0051] Still referring to FIG. 1, an exemplary method of
manufacturing substantially air-impermeable composite material 121
will now be described. During the manufacturing process, sheet-form
film 122, loop material 124, and molten resin 126 are delivered to
nip 108. Film 122 and loop material 124 are delivered to nip 108
from rolls 128 and 130 by rotating shafts 116 and 118 on which
those rolls are mounted, and molten resin 126 is extruded into nip
108 from extruder 114. In the exemplary method, film 122, loop
material 124, and molten resin 126 are formed substantially
entirely of the same type of material. In particular, each of those
components is formed substantially entirely of polypropylene. As
discussed below, one or more of these components may include a
polymer or polymers different from polypropylene, but the vast
majority (e.g., at least about 85 percent by weight) of the
materials used to form these components is polypropylene.
[0052] The melting temperatures of the materials from which film
122, loop material 124, and molten resin 126 are formed typically
differ from one another by no more than about 25 degrees Fahrenheit
(e.g., no more than about 20 degrees Fahrenheit, no more than about
15 degrees Fahrenheit, no more than about 10 degrees Fahrenheit).
As discussed above, film 122, loop material 124, and molten resin
126 each include a substantial amount of polypropylene. Thus,
substantial portions of the material from which these components
are formed will have similar (e.g., substantially the same) melting
temperatures. As a result of the similar melting temperatures of
these materials, it can be quite complicated to bond molten resin
126 to loop material 124 without melting the loops of loop material
124. However, as discussed below, it has been found that this can
be accomplished by using manufacturing process parameters and
materials described herein.
[0053] Film 122 is a sheet-form polypropylene cast film having a
thickness of about one mil to about five mils (e.g., about three
mils). The use of film 122 in combination with molten resin 126
helps to ensure that composite material 121 is substantially
air-impermeable.
[0054] Referring briefly to FIG. 2, which is an enlarged view of
region 2 in FIG. 1, loop material 124 includes a spunbond
polypropylene substrate 125 having polypropylene staple fibers 127
and 129 needled therethrough to form loops 131 that extend from one
side of substrate 125. Substrate 125 has a basis weight of about 17
grams per square meter. Staple fibers 127 and 129 are provided on
substrate 125 in a 4:1 ratio. Staple fibers 127 are available from
Asota Mills, under product number L10D. Staple fibers 129 are
available from Asota Mills, under product number CL10. Loop
material 124 has an overall basis weight of about 1.3 ounces per
square yard (osy) to about 1.6 osy (e.g., about 1.47 osy).
[0055] In order to form loop material 124, staple fibers 127 and
129 are provided on the surface of substrate 125 to form a staple
fiber layer. The combination of substrate 125 and staple fibers 127
and 129 are then fed through a needling machine that includes
forked needles positioned above the staple fibers 127, 129. As
substrate 125 and staple fibers 127, 129 pass under the needles,
the needles are driven through the staple fiber layer and substrate
125. Due to the construction of the needles, as the needles are
driven downward through substrate 125, they carry some of staple
fibers 127, 129 through substrate 125 to form loops 131. As the
needles are then retracted out of substrate 125, the looped staple
fibers 131 remain extending from the under side of substrate 125
opposite the staple fiber layer. Exemplary methods of forming loop
materials similar to loop material 124 are described in greater
detail in US 2004/0157036 and US 2009/0203280, which are
incorporated by reference herein.
[0056] Referring again to FIG. 1, molten resin 126 is a blend of
polypropylene and a small amount of polyethylene. The blend
typically includes at least about 85 percent by weight (e.g., at
least about 90 percent by weight, at least about 95 percent by
weight) polypropylene and at most about 15 percent by weight (e.g.,
at most about 10 percent by weight, at most about 5 percent by
weight) polyethylene. The small amount of polyethylene helps to
enhance flow characteristics of molten resin 126 such that the
molten resin can be delivered from extruder 114 to nip 108 in a
highly controlled fashion.
[0057] Molten resin 126 is delivered to nip 108 between film 122
and loop material 124. Extruder 114 is positioned about six inches
to about 18 inches (e.g., about 12 inches) above nip 108. Molten
resin 126 is extruded through extruder die 115 at a pressure of
about 2000 psi gauge to about 3000 psi gauge (e.g., about 2400 psi
gauge) and is delivered to the nip 108 at a temperature of about
500 degrees Fahrenheit to about 650 degrees Fahrenheit (e.g., about
580 degrees Fahrenheit). As a result, a layer of resin 126 that is
about 0.5 mil to about 1.5 mils (e.g., about one mil) thick is
formed between film 122 and loop material 124.
[0058] As shown in FIG. 1, extruder 114 has been adjusted such that
molten resin 126 is delivered approximately into the center of nip
108. As a result, molten resin 126 contacts film 122 and loop
material 124 at substantially the same time.
[0059] Rolls 102, 104, and 106 are configured to create a nip
pressure of about 10 psi gauge to about 15 psi gauge. In some
embodiments, rolls 102, 104, and 106 are configured to created a
nip pressure of about 12 psi gauge), which equates to a pressure of
about 30 pounds per linear inch. The pressure in pounds per linear
inch can be determined as a function of the gauge pressure and the
diameter and length of pressure roll 102. The rotation of pressure
roll 102 and backing roll 104 in opposite directions draws film
122, loop material 124, and molten resin 126 through nip 108. As
these materials pass through nip 108, the pressures within nip 108
compress resin 126 between film 122 and loop material 124. The
relatively low nip pressure helps to ensure that loops extending
from loop material 124, which contact the peripheral surface of
pressure roll 102, are not damaged (e.g., do not melt) during the
lamination process.
[0060] In addition, pressure roll 102 and backing roll 104 are
chilled to a temperature of about 50 degrees Fahrenheit to about 80
degrees Fahrenheit (e.g., about 65 degrees Fahrenheit). Cooled
rolls 102 and 104 facilitate cooling of molten resin 126 as it
passes through nip 108. In addition, the reduced temperature of
rolls 102 and 104 help to prevent the loops of loop material 124
from melting due to the high temperature of molten resin 126.
[0061] It has also been found that the weight of substrate 125 of
loop material 124 is sufficient to prevent loops 131 of loop
material 124 from melting under the processing conditions discussed
above. At the same time, loop material 124 allows the resulting
composite material 121 to have a desired flexibility and, because
loop material 124 is a relatively inexpensive material, helps to
keep the cost of manufacturing composite material 121 well below
the cost of manufacturing substantially air-impermeable methods
using certain conventional manufacturing techniques.
[0062] FIG. 3 illustrates an enlarged schematic view of composite
material 121. As shown in FIG. 3, composite material 121 includes a
film layer formed of film 122, a loop material layer formed of loop
material 124, and a resin layer formed of resin 126. These multiple
layers are bonded together as a result of the lamination process
described above. In particular, the portion of film 122 that
contacts molten resin 126 during the lamination process melts and
becomes welded to the resin layer. Similarly, as schematically
illustrated in FIG. 3, the portions of substrate 125 and staple
fibers 127, 129 of loop material 124 that contact molten resin 126
during the lamination process become encapsulated by molten resin
126 and melt such that loop material 124 becomes welded to the
resin layer. Despite the high temperature of molten resin 126 and
the fact that loop material 124 and molten resin 126 are formed
primarily of the same type of material (i.e., polypropylene) and
thus have similar melting temperatures, the hook-engageability of
loops 131 of loop material 124 is preserved during the lamination
process. The temperature and flow rate of molten resin 126, the
temperature of chilled rolls 102, 104, and the construction of loop
material 124 are selected to prevent loops 131 from melting and
thus losing their hook-engageability. As a result, loops 131, which
extend from the outer surface of the loop material layer of
composite material 121, are hook-engageable. Composite material 121
can, for example, be engageable by the hooks of certain hook
fastener products, such as HTH 819 hooks and/or HTH 851 hooks, both
available from Velcro USA (Manchester, N.H.). Thus, as a result of
the manufacturing process described above, composite material 121
can advantageously be used to make products that benefit from
having one or more hook-engageable surfaces.
[0063] Referring again to FIG. 1, composite material 121 is
embossed prior to being wound into a roll 123 around a winder 120.
To emboss composite material 121, composite material 121 is passed
through an embossing station 150, which includes an embossing roll
152 and a rubber (e.g., siliconized rubber) backing roll 154. A nip
156 is formed between embossing roll 152 and backing roll 154.
Embossing roll 152 is a heated (e.g., steam-heated), steel roll
that has a pattern of raised honeycomb-shaped areas 158 extending
from its outer surface. Alternatively, embossing roll 152 can
include any of various other raised patterns, such as combinations
of diamonds, squares, triangles, circles, lines, curves (e.g.,
sinusoidal curves), logos, etc.
[0064] Embossing roll 152 is heated to a temperature of about 300
degrees Fahrenheit to about 400 degrees Fahrenheit (e.g., about 303
degrees Fahrenheit), and embossing roll 152 and backing roll 154
are configured to create a pressure of about 35 psi gauge to about
80 psi gauge (e.g., about 65 psi gauge) within nip 156. Composite
material 121 is passed through nip 156 at a rate of about 20 feet
per minute to about 80 feet per minute (e.g., about 30 feet per
minute). As composite material 121 passes through nip 156, raised
areas 158 of embossing roll 152 contact the film layer of composite
material 121 and compress adjacent regions of composite material
121 between embossing roll 152 and rubber backing roll 154, forming
depressions in composite material 121. It is believed that these
depressions act as natural hinge points that facilitate folding or
bending of composite material 121, as will be discussed further
below.
[0065] In certain embodiments, the loop material layer of composite
material 121 provides composite material 121 with an average peel
strength of about 30 grams per inch width to about 100 grams per
inch width (e.g., about 35 grams per inch width to about 45 grams
per inch width). A test developed by Velcro Group Corporation is
used to determine the peel strength of composite material 121. The
test involves the use of a 1.5 inch wide and 2.0 inch long sample
of composite material 121 and a 1.0 inch wide by 1.0 inch long
sample of 851 hook tape, manufactured by Velcro USA (Manchester,
N.H.). A 1.0 inch wide by 2.0 inch wide piece of SMS nonwoven
fabric is secured to the back of the hook sample using double-sided
tape so that a 1.0 inch wide by 1.0 inch long tab of SMS nonwoven
fabric extends from the end of the hook sample. The hook tape
sample is superimposed upon the composite material sample (face to
face) using minimal pressure (i.e., the amount of pressure
necessary to create just enough hook and loop engagement so as to
be able to continue with the test procedure). The hook tape and
composite material samples are superimposed in a manner such that
the machine direction of the hook sample is perpendicular to the
machine direction of the loop material of the composite sample. A
roll down machine having three rollers that each have a weight of
about 4.5 pounds, a width of about 1.75 inches, and a durometer of
80 is then used to engage the loop material of the composite
material sample with the hooks of the hook tape sample. The rollers
of the roll down machine are rolled over the superimposed samples
at a speed of 12 inches per minute. The rollers make two full
cycles over the superimposed samples, where one full cycle
constitutes rolling over the entire length of the superimposed
samples and then back again. An example of a roll down machine that
can be used for this procedure is the RD-3000 roll down machine
available from ChemInstruments.
[0066] The SMS nonwoven fabric tab extending from the end of the
hook sample and the corresponding end region of the composite
material sample are then inserted into clamps of a tensile tester.
The SMS nonwoven fabric tab extending from the hook tape sample is
placed into a moveable, upper clamp of the tensile tester, and the
end region of the composite material sample is placed into a
stationary, lower clamp of the tensile tester. The clamps have a
maximum gauge length (i.e., the opening between upper and lower
clamps) of about 0.5 inch. With the samples secured in the clamps,
the upper clamp is moved away from the lower clamp at a rate of 12
inches per minute. The tensile tester is configured to begin
recording data when a force of 0.05 pounds is measured, and the
tensile tester is configured to move the jaws apart from one
another until the jaws are separated by at least 1.5 inches. An
example of a suitable tensile tester is the MTS Sintech 1/S. The
above-described test is performed at standard atmosphere (69.8-77.0
degrees Fahrenheit and 45-55 percent relative humidity), and the
test samples are preconditioned in standard atmosphere for 22-26
hours prior to testing.
[0067] As the jaws are separated from one another, the tensile
tester measures the resistance force resulting from the engagement
of the hooks and loops. This average measured force over the course
of separation of the samples is then determined and divided by the
width of the engaged samples (in this case, 1.0 inch) to determine
the peel strength in grams per lineal inch. The above-described
test is repeated ten times and the average peel strength is
determined based on those ten tests.
[0068] In some embodiments, the loop material layer of composite
material 121 provides composite material 121 with an average shear
strength of about 2000 psi to about 5000 psi (e.g., about 3400 psi
to about 4200 psi). A test developed by Velcro Group Corporation is
used to determine the shear strength of composite material 121.
This test involves the use of a 1.5 inch wide by 2.0 inch long
sample of composite material 121 and a 1.0 inch wide by 2.0 inch
long sample of 851 hook tape, manufactured by Velcro USA
(Manchester, N.H.). The hook tape sample is backed with a 1.0 inch
wide by 2.0 inch long piece of masking tape to prevent breaking of
the hook tape sample during the test. The hook tape sample is
superimposed upon the composite material sample and the samples are
engaged by a roll down machine in the manner described above. As a
result, end regions of the samples overlap by 0.5 inch. As a
result, a 1.5 inch length of the composite material sample extends
from one end of the overlapped region and is not facially engaged
with the hook tape sample, and a 1.5 inch length of the hook tape
sample extends from the opposite end of the overlapped region and
is not facially engaged with the composite material sample. The
hook tape and composite material samples are superimposed in a
manner such that the machine direction of the hook sample and the
machine direction of the loop material of the composite sample
extend in the same direction. The free, non-facially engaged end
regions of the hook tape and composite material samples are then
inserted into clamps of a tensile tester (e.g., the MTS Sintech 1/S
tensile tester). The end region of the hook tape sample is placed
into a moveable, upper clamp of the tensile tester, and the end
region of the composite material sample is placed into a
stationary, lower clamp of the tensile tester. The clamps have a
maximum gauge length (i.e., the opening between upper and lower
clamps) of about 2.0 inch. With the tabs of the samples secured in
the clamps, the upper clamp is moved away from the lower clamp at a
rate of 12 inches per minute. The clamps are moved apart a
sufficient distance to achieve a shearing of the engaged hook tape
and composite material samples. The above-described test is
performed at standard atmosphere (69.8-77.0 degrees Fahrenheit and
45-55 percent relative humidity), and the test samples are
preconditioned in standard atmosphere for 22-26 hours prior to
testing.
[0069] As the jaws are separated from one another, the tensile
tester measures the resistance force resulting from the engagement
of the hooks and loops. The peak load (i.e., highest measured
force) is then divided by the overlap area of the samples (in this
case, 0.5 inch long by 1.0 inch wide) to determine the shear
strength in pounds per square inch. The above-described test is
repeated ten times and the average shear strength is determined
based on those ten tests.
[0070] Because each of the various components or layers of
composite material 121 are formed primarily of the same type of
material (i.e., polypropylene), composite material 121 is
recyclable. As a result, composite material 121 can be readily used
in many single-use or limited-use products, some of which are
described below, in an environmentally conscious and cost-efficient
manner.
[0071] In addition to being hook-engageable and recyclable, the
combination of film 122, loop material 124, and the cooled resin
126 therebetween cooperate to make composite material 121
substantially air-impermeable. Composite material 121 can, for
example, have an air-permeability of 0 cm.sup.3/s/cm.sup.2 (0
ft.sup.3/min/ft.sup.2), as tested using ASTM D737-96.
[0072] After composite material 121 exits nip 108, the composite
material is wound into a roll 123 around winder 120. Winder 120 can
provide a tension of about 50 psi gauge to composite material 121
as composite material 121 is wound onto winder 120. Winding
composite material 121 into a roll allows the composite material to
be conveniently shipped or stored in mass quantities.
[0073] The exemplary method illustrated in FIG. 1 can be used to
efficiently make composite material 121 at high rates of speed. For
example, the method can be used to make composite material 121 at a
rate of at least about 200 linear feet per minute (e.g., at least
400 linear feet per minute, at least about 600 linear feet per
minute). In some cases, composite material is produced at a rate of
about 200 linear feet per minute to about 800 linear feet per
minute (e.g., about 400 linear feet per minute to about 600 linear
feet per minute). The width of composite material 121 produced is
typically about six feet wide. However, the composite material can
be formed in wider or narrower swaths. As a result of the rapid
production speeds of system 100, the exemplary method can be used
to inexpensively manufacture material that is substantially
air-impermeable, hook engageable, and recyclable.
[0074] As discussed above, composite material 121 can be used to
form any of various different products. An example of one such
product is a medical compression device (e.g., a blood pressure
cuff) 200, which is illustrated in FIGS. 4 and 5. Blood pressure
cuff 200 includes an inflatable pouch 202 and a strap portion 204
integrally extending from inflatable pouch 202. A fitment 208
capable of coupling with a flexible tube 210 (shown in FIG. 6) that
is connected to a hand-operated pump 212 (also shown in FIG. 6) is
in fluid communication with inflatable pouch 202. As described
below, inflatable pouch 202 and strap portion 204 can be formed by
folding a sheet of composite material 121 and then welding the
overlapping halves of the folded sheet of composite material 121
together. As a result of this process, welds 214 are formed around
the perimeter of inflatable pouch 202 and around the perimeters of
strap portion 204.
[0075] Referring to FIG. 5, loops 131 of the loop material layer of
composite material 121 extend from the outer surfaces of inflatable
pouch 202 and strap portion 204. Loops 131, as discussed above, are
hook-engageable. In addition, loops 131 provide a soft, comfortable
surface for contacting the user's skin during use. In addition, a
hook fastener 216 including an array of loop-engageable hooks is
attached (e.g., welded) to an outer surface of strap portion 204.
The hook fastener 216 is arranged so that when blood pressure cuff
200 is wrapped around a patient's arm and strap portion 204
overlaps itself, hook fastener 216 can releasably engage loops 131
extending from the opposite outer surface of strap portion 204 to
tightly secure blood pressure cuff 200 around the patient's arm.
The loop-engageable hooks of hook fastener 216 can, for example, be
of molded form available from Velcro, USA under designation HTH
819, HTH 851, or any of various other hooks that are capable of
releasably engaging loops 131 of composite material 121. Typically,
the hooks are formed primarily of (e.g., entirely of) the same
polymer as the various components of composite material 121. In
certain embodiments, for example, hook fastener 216, film 122 of
composite material 121, and loop material 124 of composite material
121 are formed substantially entirely of polypropylene, and resin
126 of composite material 121 is formed primarily of polypropylene.
As discussed above, for example, the resin layer of composite
material 121 can include at least about 85 percent by weight (e.g.,
at least about 90 percent by weight, at least about 95 percent by
weight) polypropylene and at most about 15 percent by weight (e.g.,
at most about 10 percent by weight, at most about 5 percent by
weight) polyethylene.
[0076] FIG. 6 shows blood pressure cuff 200 wrapped around the
upper portion of a patient's arm 218. Flexible tube 210, mated with
fitment 208, is used as a conduit extending from pump 212 to fill
inflatable pouch 202 with air as pump 212 is operated. This
tightens blood pressure cuff 200 around the patient's arm 218 until
blood flow is constricted, and enables measurement of blood
pressure during gradual release of air from pouch 202. Typically,
automatic blood pressure detecting devices with which blood
pressure cuff 200 can be used are adapted to sense (e.g., by
audible signal) blood passing through the patient's arm both as
blood pressure cuff 200 is inflated and as blood pressure cuff 200
is deflated. By sensing blood passing through the patient's arm as
the cuff is being inflated, the blood pressure detecting device is
able to determine the point at which blood can no longer be
detected flowing through the patient's arm. At this point the cuff
is slowly deflated. The points at which blood flow is first sensed
and last sensed by the blood pressure detecting device as the cuff
is being deflated can be used to indicate the systolic and
diastolic blood pressure of the patient.
[0077] It has been found that the embossed pattern of composite
material 121 helps to reduce the noise associated with inflating
and deflating blood pressure cuff 200. Without wishing to be bound
by theory, it is believed that the depressions formed in composite
material 121 during the embossing process act as hinges and thus
decrease bending resistance of composite material 121. It is
further believed that this decreased bending resistance decreases
the noise associated with inflating and deflating blood pressure
cuff 200, and thus improves the ability of the blood pressure
detecting device to accurately identify the point at which blood
flow through the patient's arm is no longer audible. This can, for
example, decrease the likelihood of the blood pressure detecting
device being prematurely unable to sense blood flow through the
patient's arm as a result of background noise caused by the
inflating cuff. As a result, the likelihood of the blood pressure
detection device deflating blood pressure cuff 200 prematurely and
having to restart the blood pressure detection procedure can be
reduced.
[0078] Due to the efficiency with which composite material 121 can
be manufactured using the various methods described herein, blood
pressure cuff 200 can be manufactured relatively inexpensively.
This allows blood pressure cuff 200 to be manufactured as a limited
use (e.g., single-use) device that can, for example, be used in
trauma rooms or other places where the cuff may become contaminated
with blood or other bodily fluids during use. After becoming
contaminated, the blood pressure cuff 200 can simply be discarded.
In addition, because the various components of composite material
121 are formed primarily of the same material (e.g.,
polypropylene), blood pressure cuff 200 is readily recyclable. This
is a beneficial characteristic for products such as blood pressure
cuff 200, which will be used only a limited number of times (e.g.,
ten times or fewer, or only once) before being discarded.
[0079] FIG. 7 schematically illustrates a method of manufacturing
multiple medical compression devices (e.g., blood pressure cuffs)
of the type illustrated in FIGS. 4-6. As shown in FIG. 7, this
exemplary method uses a horizontal poucher system 300 to overlap
(e.g., by folding) and weld a single sheet of composite material
121 in selected bonding regions to form inflatable pouch 202 and
strap portion 204 of blood pressure cuffs 200. Beginning at the
right side of FIG. 7, the sheet of composite material 121 is led
from composite roll 123, which is positioned on a rotatable shaft
302, into a former 304 where the composite material 121 is folded
about an axis A to form overlapped areas of composite material 121.
Once centered on former 304, composite material 121 passes through
drive stations 306 and 308, which are located near the entry and
exit, respectively, of system 300 and are coupled to act in unison.
Drive station 306 includes rolls extending the full width of the
folded composite material to pull the sheet-form composite through
the former 304. In coordination with the downstream drive station
308, drive station 306 also tensions the material. Due to the
arrangement of composite material 121 on composite roll 123, after
being folded, folded regions of film 122 contact one another and
loops 131 extend from the outer surfaces of the folded sheet. As a
result, the outer surfaces of the folded composite material 121 are
hook-engageable.
[0080] By indexing action, the sheet form composite material 121
passes from former 304 to a pair of welding stations 310 and 312
where sealing bars weld selected overlapped regions of the folded
composite material 121 together. The folded composite material 121
then passes from the weld stations 310 and 312 to an insertion
station 314. As the folded composite material 121 passes through
insertion station 314, portions of the folded composite material
121 between welds formed by weld stations 310 and 312 are engaged
by a pair of oppositely acting suction cups 316. The top of the
pouch between the welds is opened to enable the placement of
fitment 208 in an opening between the welds.
[0081] One alternative method for opening the sides of the pouch is
to use loop-engageable fasteners (e.g., hook fasteners) to engage
and pull back the loop bearing sides of the folded composite
material 121. This can be used to open the sides slightly, at which
time spreader blades can be inserted and spread apart to complete
the action. Another method for opening is to place the fold axis A
slightly off center of the overall web width. Thus, when folded
about axis A, one edge of the folded material will extend higher
than the other. Given height difference between opposed edges,
high-pressure air blown into the pouch area or mechanical means
such as pinchers can open the sides.
[0082] With fitment 208 held in place at the opening, downstream
drive station 308, in conjunction with drive station 306, indexes
the folded and welded material from insertion station 314 to a top
seal station 318. Sealing jaws of top seal station 318 with motion
similar to that of the heat seal bars at weld stations 310 and 312,
can be moved inward to weld the top edge of the folded composite
material 121 and can be moved outwardly to release the top edge of
the folded composite material 121. While system 300 is forming the
welds at weld stations 310 and 312, and inserting fitment 208 at
insertion station 314, the sealing jaws at top seal station 318
engage to seal shut the top of the folded composite material 121
along the portion of the folded composite material 121 that
ultimately becomes strap portion 204 of blood pressure cuff 200.
Simultaneously, sealing jaws at an adjacent top seal station 320
engage to weld the top edge of the folded composite material 121 to
form inflatable pouch 202 of blood pressure cuff 200. This weld
also functions to secure fitment 208 in place. As discussed above,
fitment 208 can subsequently be connected to conduit 210 and pump
212 to allow inflation of pouch 202.
[0083] Downstream cutting jaws 322, 324 sever the folded composite
material 121 along the trailing weld adjacent inflatable pouch 202.
This severs the leading blood pressure cuff preform from the
remainder of the continuous sheet form composite material 121 that
is in the process of being formed into additional blood pressure
cuff preforms. After severing the leading blood pressure cuff
preform from the remainder of composite material 121, hook fastener
216 is welded to the blood pressure cuff preform to complete the
formation of blood pressure cuff 200.
[0084] A repeat length L.sub.1 for system 300 is established by the
desired length of blood pressure cuff 200 and extends from sealing
bar 310 to the downstream weld that was previously formed by
sealing bar 310. Similarly, the distance A1 between weld stations
310 and 312 are established by the desired length of inflatable
pouch 202 of blood pressure cuff 200.
[0085] While certain embodiments have been described, other
embodiments are possible.
[0086] In certain embodiments, for example, the embossing of
composite material 121 can be performed by an embossing station
that is separate from system 100. In such embodiments, for example,
composite material 121 can be wound onto roll and then transported
to an embossing station, where the roll of composite material 121
is unwound and passed through a nip formed between an embossing
roll and backing roll of the type described above.
[0087] While composite material 121 has been described as being
embossed, in certain embodiments, composite material 121 is not
embossed prior to being formed into a product, such as a
compression device. In some embodiments, as an alternative to or in
addition to embossing composite material 121, a patterned film can
be introduced into nip along with molten resin and loop material.
The patterned film can facilitate folding of the material and, in
the case of blood pressure cuffs formed from the composite
material, can help to reduce noise created by the cuff as it is
inflated.
[0088] While support roll 106 of system 100 has been described as
contacting pressure roll 102 to prevent or reduce bowing of
pressure roll 102 as a result of high pressures within nip 108, in
certain embodiments, support roll 106 is moved to a disengaged
position such that support roll 106 does not contact pressure roll
102. Such an arrangement can be used, for example, when pressures
within nip 108 are not sufficiently high to cause bowing of
pressure roll 102. As an alternative to moving support roll 106 to
a disengaged position, support roll 106 can be entirely removed
from system 100 in certain cases.
[0089] While the compression devices (e.g., blood pressure cuffs)
200 have been described as being manufactured by folding composite
material 121 and then welding overlapping portions of the composite
material together, other types of manufacturing techniques can be
used. In certain embodiments, as schematically illustrated in FIG.
8, for example, two separate sheets of composite material 121 are
welded together to form the compression devices. The two sheets of
composite material 121 are fed from rolls 123 in an overlapping
manner. The sheets are welded together using a welding process
similar to the welding process described above with respect to FIG.
7. However, in addition to using top seal stations 318 and 320 to
provide welds, bottom seal stations 318' and 320' are provided to
weld the overlapped sheets of composite material 121 along the
bottom edge of those sheets. The other steps of the manufacturing
process can be substantially the same as those steps described
above with respect to FIG. 7.
[0090] While the above-described manufacturing methods describe
welding the hook fasteners to composite material 121 after the
composite material or materials has/have been formed into the shape
of the blood pressure cuffs, the hook fasteners can alternatively
be welded onto composite material 121 prior to forming the
composite material into the shape of blood pressure cuffs. For
example, before winding composite material 121 onto winder 120,
composite material can pass through a welding station that welds
hook fasteners at longitudinally spaced apart regions of the
composite material. As a result, after forming the composite
material into blood pressure cuffs, the hook fasteners will be
located only along a desired portion of the length of the blood
pressure cuffs.
[0091] Alternatively, prior to winding composite material 121 onto
winder 120, the composite material can pass through a welding
station that continuously welds one or more hook fastener strips to
the composite material. The hook fastener strips can, for example,
be provided in a roll and can be delivered to a nip formed between
a support roll and a thermal sealing member. In some embodiments,
the hook fastener strips can be provided as continuous strips that
extend along the entire length of the blood pressure cuff.
[0092] While the hook fasteners have been described as being welded
to composite material 121, other techniques can be used. In some
embodiments, for example, the hook fasteners are joined in situ to
composite material 121. In such embodiments, composite material 121
may be passed through a nip formed between a mold roll including
hook-shaped cavities and a pressure roll along with molten resin.
The molten resin is pressed into the hook-shaped cavities to form
hooks. At the same time, the molten resin bonds to composite
material 121. The general concept of in situ lamination is
explained in U.S. Pat. No. 5,260,015 by Kennedy et al., and in situ
lamination of strips of molded hooks, per se, is disclosed in U.S.
Pat. No. 6,205,623 by Shepard et al., which are hereby incorporated
by reference herein.
[0093] While the compression devices 200 have been described as
blood pressure cuffs, other types of compression devices can be
manufactured using methods similar to those described above. FIG.
9, for example, illustrates a sequential compression device 400
that can be manufactured using the composite material described
above and using methods similar to those described above.
Sequential compression device 400 is a disposable wrap that
includes multiple inflatable compartments 402. A fitment 408 is
connected to each of the inflatable compartments 402. Fitments 408
permit a tube from a pump (e.g., an air pump) to be connected
thereto to allow inflatable compartments 402 to be selectively
inflated and deflated. A hook fastener strip 416 is attached to the
polymeric film of the composite material of compression device 400
along the lower edge of compression device 400. Loop material 131
extends from the outer surface of the composite material opposite
hook fastener strip 416, and thus is shown in dashed lines. As
shown in FIG. 10, hook fastener strip 416 can engage loop material
131 to form a sleeve having multiple annular inflatable
compartments along its length.
[0094] During use, sequential compression device 400 is secured in
the form of a sleeve around a limb (e.g., a leg) of a patient by
wrapping the composite material around the limb of the patient and
then fastening the hooks of hook fastener strip 416 to loop
material 131. Each of the inflatable compartments 402 is then
connected to a pump (e.g., an air pump) via separate tubes.
Compartments 402 are then sequentially inflated and deflated. Using
sequential compression device 400 in this manner can improve blood
flow and prevent clot formation. Such use can help to prevent the
development of deep vein thrombosis (DVT) and similar conditions in
immobile patients.
[0095] Sequential compression devices 400 can be formed using
systems and methods similar to those illustrated in FIGS. 7 and 8.
However, the system would typically be equipped with additional
welding stations that can be used to form the increased number of
inflatable compartments 402 along the length of sequential
compression device 400. In addition, hook fastener strip 416 would
be applied along one of the lengthwise edges of compression device
400.
[0096] While compression device 400 has been described as having a
hook fastener strip that engages loop material to form a sleeve, in
certain embodiments, opposite edge regions of the compression
device are thermally welded to form a permanent sleeve. In such
embodiments, prior to use, the compression device would be slid
onto the limb of the patient rather than being wrapped around the
patient's limb and then fastened.
[0097] In addition to blood pressure cuffs and sequential
compression devices, various other types of compression devices can
be manufactured using the composite material described above. One
such device is an inflatable tourniquet cuff. The inflatable
tourniquet cuff can be formed and operated in substantially the
same manner as the blood pressure cuffs described above. Tourniquet
cuffs can, however, be provided in a wide range of sizes to allow
the tourniquets be used on various different body parts of
different patients. Some inflatable tourniquet cuffs can, for
example, be sized to fit around a patient's arm and other
inflatable tourniquet cuffs can be sized to fit around a patient's
leg. Such tourniquet cuffs can be used to prevent blood flow to the
patient's arm or leg during use. For example, during a surgical
procedure on a patient's arm, the arm-sized cuff can be wrapped
around the patient's arm and then inflated to stop blood flow to
the patient's arm. Similarly, during a surgical procedure on a
patient's leg, the arm-sized cuff can be wrapped around the
patient's leg and then inflated (e.g., by connecting a tube from a
pneumatic pump to the fitment of the tourniquet cuff and operating
the pump) to stop blood flow to the patient's arm. Use of the
tourniquet cuffs in this manner can permit the surgeon to work in a
bloodless operative field. Smaller tourniquet cuffs can also be
made for use on smaller limbs, such as fingers and toes, of
patients.
[0098] Another type of device that can be manufactured using the
composite materials described above is an inflatable immobilizing
device, such as an inflatable cast. Such casts can, for example, be
sized and shaped for use on a patient's ankle or wrist.
[0099] While film 122 has been described as a two mil thick, cast,
polypropylene film. Other types of films can alternatively be used.
For example, films having a thickness of about 1 mil to about 5
mils can be used.
[0100] While loop material 124 has been described as including a 17
grams per square meter spunbond polypropylene substrate through
which staple fibers 127 and 129 are needled, other types of
nonwoven fabrics can alternatively be used to form the substrate of
the loop material. In some embodiments, for example, staple fibers
127 and 129 are needled through a 30 grams per square meter
polypropylene SMS substrate to form the loop material. In such
embodiments, any of the various needling methods described or
referenced above can be used to make the loop material. The
resulting loop material has an overall basis weight of about 1.7
osy to about 2.0 osy.
[0101] In some embodiments, materials other than nonwoven materials
are used as the substrate of the needled loop material. Examples of
such materials include films and knits.
[0102] While loop material 124 has been described as including
loops formed of staple fibers available from Asota Mills, under
product numbers L10D and CL10, it should be understood that various
other types of staple fibers can be used so long as those staple
fibers are capable of being needled through a substrate to form
loops and are formed of a material desired for the particular
composite material being formed (e.g., formed substantially
entirely of a certain type of polymeric material, such as
polypropylene).
[0103] As an alternative to the needled loop materials described
above, in certain embodiments, other types of hook-engageable
materials can be used. Examples of such hook-engageable materials
include SMS fabric, spunbond fabric (e.g., spunbond polypropylene
(commodity grade)), and knits. However, we have found the
above-described needled loop materials to be particularly
advantageous in certain cases because they typically provide longer
useful life expectancies, and it is believed that the needled loop
materials are particularly effective at preventing the
hook-engageable fibers (i.e., loops) from being destroyed (e.g., by
melting) during manufacturing processes that involve the
application of molten resin to the needled loop material.
[0104] While molten resin 126 has been described as a mixture of
polymers (i.e., polypropylene and polyethylene), in certain
embodiments, the molten resin is formed entirely of a single
polymer (e.g., polypropylene).
[0105] While the film, hook-engageable material, and molten resin
of those composite materials discussed above have been described as
being formed primarily of or entirely of polypropylene, they can
alternatively be formed primarily of or entirely of other
materials. In certain embodiments, for example, the film,
hook-engageable material, and molten resin are formed primarily of
or entirely of polyethylene. Composite materials of this
construction can, for example, be advantageous for applications
that benefit from increased flexibility or stretchability while
still providing a substantially air-impermeable barrier.
Alternatively, the film, hook-engageable material, and molten resin
can be formed primarily of or entirely of nylon (e.g., lightweight
nylon knit).
[0106] While certain composite materials discussed above have been
described as being substantially air-impermeable, in certain
embodiments, the composite material is not air-permeable. In some
embodiments, for example, the composite material is
liquid-impermeable but is air-permeable. One example of such a
composite material is made with a perforated polymeric film. The
perforations are sized such that liquid is unable to pass through
the film while air and other gases are allowed to pass through the
perforations. Such composite materials can be useful, for example,
for forming products that benefit from liquid-impermeability but
are not required to be inflatable.
[0107] In addition to the compression devices described above, any
of various other types of products can be manufactured using the
composite materials described herein. In some embodiments, for
example, medical cold wraps can be formed using manufacturing
processes similar to those described above. In certain embodiments,
for example, rather than placing a valve or fitment into a pouch
formed by the composite material or materials, the pouch can be
filled with a cooling liquid, such as a cooling chemical solution
or water, and then the composite material or materials can be
welded in a manner to seal the cooling liquid within the pouch.
Such a product can, for example, be used as a medical cold wrap
that can be secured around a body part of a user to cool the body
part. To use this type of product, the product would be placed in a
freezer until the cooling liquid is cooled to a desired temperature
and then wrapped around the user's body part and fastened to cool
the body part. Such products are useful, for example, to reduce
swelling of the body part. Examples of similar wraps are described
in US 2004/0181156, which is incorporated by reference herein. In
addition to the above-described compression devices and medical
wraps, any of the various other types of products described in US
2004/0181156 can be manufactured using the composite materials
described herein.
[0108] In some embodiments, the composite material is used in the
construction of urinary drain bags. As shown in FIG. 11, for
example, a urinary drain bag 500 includes a first wall 502 formed
from the liquid-impermeable and hook-engageable composite material
of the type described above. A second wall 504 of drain bag 500 is
formed of a liquid-impermeable polymeric film. The loop layer of
the composite material is exposed along an outer surface of the
rear wall of drain bag 500. In this manner, drain bag 500 can be
releasably fixed to any surface having engageable hooks extending
therefrom. In certain cases, for example, hook tape can be applied
to a hospital bed and drain bag 500 can be conveniently secured to
the hospital bed by engaging the loops of the composite material to
the hooks of the hook tape. Such an arrangement can make it easier
for drain bags to be replaced by medical personnel. Any of various
other types of medical bags that would benefit from being
releasably secured to a surface can similarly be formed from the
hook-engageable composite materials described herein.
[0109] Referring again to FIG. 1, while molten resin 126 has been
described as being introduced directly into nip 108 such that
molten resin 126 contacts film 122 and loop material 124 at
substantially the same time, in certain embodiments, molten resin
126 is applied first to film 122, and film 122 then carries molten
resin 126 into nip 108. This technique can provide molten resin 126
with additional time to cool prior to contacting loop material 124,
which can help to prevent loops 131 extending from the outer
surface of loop material 124 from melting and becoming bonded
together. As a result, this technique can help to ensure that loops
131 extending from loop material 124 remain capable of engaging
hooks of hook fastener elements after loop material 124 is bonded
to film 122 to form the composite material.
[0110] While the composite materials of embodiments above have been
described as including a hook-engageable surface, in certain
embodiments, composites having only surfaces that are not
hook-engageable are formed. Such composites can be formed using
manufacturing processes similar to those described above. In
certain embodiments, for example, a needled loop material having a
17 grams per square meter spunbond polypropylene substrate is fed
into nip 108 formed between pressure roll 102 and backing roll 104.
Molten resin is applied to the loop material to form a resin layer
that is about 2 mils thick. The loop material then carries the
molten resin into nip 108. Due to the relatively thin substrate of
the loop material, the increased amount of molten resin, and the
extended duration of contact between the molten resin and the loop
material, the molten resin drowns the loops extending from the loop
material. This causes the loops extending from the outer surface of
the loop material (i.e., the surface in contact with the PTFE
coated roll) to melt and become bonded to one another. As a result,
the loop material layer of the resulting composite material does
not readily engage hooks of hook fastener elements. Such a
construction can, for example, be advantageous for products in
which a soft non-hook-engageable outer surface is desired.
[0111] Other embodiments are within the scope of the following
claims.
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