U.S. patent application number 10/650098 was filed with the patent office on 2005-01-27 for air-permeable composite fabric.
This patent application is currently assigned to Malden Mills Industries, Inc., a Massachusetts corporation. Invention is credited to Colasanto, Thomas C., Rock, Moshe, Shanley, Kimberly, Shanley, Mark, Sharma, Vikram.
Application Number | 20050020160 10/650098 |
Document ID | / |
Family ID | 26794524 |
Filed Date | 2005-01-27 |
United States Patent
Application |
20050020160 |
Kind Code |
A1 |
Rock, Moshe ; et
al. |
January 27, 2005 |
Air-permeable composite fabric
Abstract
An air-permeable composite fabric is provided. The composite
fabric has an inner fabric layer, an outer fabric layer, and an
intermediate vapor barrier. The vapor barrier is selected from
adhesive material and an adhesive/membrane combination designed so
the composite fabric has a level of air permeability to allow air
flow between the first fabric layer and the second fabric layer and
a variable level of water vapor diffusion resistance that decreases
as air speed impinging on the composite fabric increases.
Inventors: |
Rock, Moshe; (Brookline,
MA) ; Sharma, Vikram; (Stoneham, MA) ;
Shanley, Mark; (Plymouth, MA) ; Shanley,
Kimberly; (Plymouth, MA) ; Colasanto, Thomas C.;
(Tolland, CT) |
Correspondence
Address: |
FISH & RICHARDSON PC
225 FRANKLIN ST
BOSTON
MA
02110
US
|
Assignee: |
Malden Mills Industries, Inc., a
Massachusetts corporation
|
Family ID: |
26794524 |
Appl. No.: |
10/650098 |
Filed: |
August 25, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10650098 |
Aug 25, 2003 |
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09378344 |
Aug 20, 1999 |
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10650098 |
Aug 25, 2003 |
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09863852 |
May 23, 2001 |
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10650098 |
Aug 25, 2003 |
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10341309 |
Jan 13, 2003 |
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10341309 |
Jan 13, 2003 |
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09863852 |
May 23, 2001 |
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60098254 |
Aug 28, 1998 |
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Current U.S.
Class: |
442/76 ;
428/195.1; 428/196; 442/118; 442/149; 442/286 |
Current CPC
Class: |
B32B 27/34 20130101;
B32B 2377/00 20130101; B32B 37/10 20130101; B32B 2250/40 20130101;
Y10T 442/3472 20150401; A41D 13/002 20130101; B32B 5/245 20130101;
Y10T 428/1476 20150115; Y10T 428/24802 20150115; B32B 27/322
20130101; B32B 2307/712 20130101; B32B 2437/00 20130101; Y10T
442/3854 20150401; B32B 27/12 20130101; B32B 27/40 20130101; B32B
2250/03 20130101; B32B 33/00 20130101; A41D 31/065 20190201; B32B
38/004 20130101; Y10T 428/23943 20150401; B32B 5/22 20130101; B32B
37/1284 20130101; B32B 2305/18 20130101; B32B 2266/0242 20130101;
B32B 2307/728 20130101; Y10T 442/20 20150401; Y10T 442/2738
20150401; Y10T 442/2213 20150401; B32B 2375/00 20130101; A41D
31/085 20190201; Y10T 442/2139 20150401; A41D 31/125 20190201; B32B
27/36 20130101; B32B 2266/0257 20130101; A41D 31/102 20190201; B32B
2038/0028 20130101; B32B 2266/0264 20130101; Y10T 428/249999
20150401; B32B 2367/00 20130101; B32B 5/26 20130101; B32B 7/12
20130101; Y10T 442/2484 20150401; Y10T 156/10 20150115; Y10T
442/335 20150401; B32B 2307/724 20130101; D06N 7/00 20130101; Y10T
428/2481 20150115; B32B 2459/00 20130101; Y10T 428/2896 20150115;
B32B 38/0012 20130101; B32B 2327/18 20130101; Y10T 442/3325
20150401; Y10T 442/647 20150401; Y10T 428/24496 20150115; B32B
2266/0278 20130101; D10B 2331/021 20130101; B32B 7/06 20130101;
Y10T 428/249982 20150401 |
Class at
Publication: |
442/076 ;
442/149; 428/196; 428/195.1; 442/286; 442/118 |
International
Class: |
B32B 027/04; B32B
005/18; B32B 027/12 |
Claims
What is claimed is:
1. An air-permeable composite fabric comprising: a first fabric
layer; a second fabric layer; and an intermediate, air-permeable
vapor barrier disposed between and bonded to said first fabric
layer and said second fabric layer; said intermediate,
air-permeable barrier layer being selected from the group
consisting of: a foamed adhesive in the form of a discontinuous
film, an adhesive in the form of a continuous film mechanically
altered by one of crushing and stretching, and a membrane disposed
between and adhered to said first fabric layer and said second
fabric layer with an adhesive and mechanically altered by
stretching, said intermediate, air-permeable vapor barrier layer
having a level of air permeability to allow air flow between said
first fabric layer and said second fabric layer, and said
intermediate, air-permeable vapor barrier layer having a variable
level of water vapor diffusion resistance that substantially
decreases as air speed of moving air impinging on said composite
fabric increases.
2. The air-permeable composite fabric of claim 1, wherein said
adhesive is selected from the group consisting of polyurethane,
acrylics, polyamides, polyesters and combinations thereof.
3. The air-permeable composite fabric of claim 1, wherein at least
one of said first fabric layer and said second fabric is rendered
hydrophilic.
4. The air-permeable composite fabric of claim 1, wherein at least
one of said first fabric layer and said second fabric layer has a
raised surface.
5. The air-permeable composite fabric of claim 1, wherein said
intermediate, air-permeable vapor barrier comprises an adhesive
selected from the group consisting of: an adhesive in the form of a
mechanically altered continuous film and a foamed adhesive in the
form of a discontinuous film.
6. The air-permeable composite fabric of claim 5, wherein said
vapor barrier is exclusively foamed adhesive in the form of a
discontinuous film.
7. The air-permeable composite fabric of claim 1, wherein said
intermediate, air-permeable vapor barrier comprises the membrane
disposed between said first fabric layer and said second fabric
layer and adhered thereto with an adhesive and mechanically altered
by stretching, said composite fabric having undergone mechanical
processing.
8. The air-permeable composite fabric of claim 1 or claim 7,
wherein said membrane is made from a material selected from the
group consisting of polyurethane, polyamide,
polytetrafluoroethylene, polyester and combinations thereof.
9. The air-permeable composite fabric of claim 7 wherein said
mechanical processing comprises controlled stretching.
10. The air-permeable composite fabric of claim 1, claim 5 or claim
7, wherein said adhesive is selected from the group consisting of
polyurethane, acrylics, polyamides, polyesters and combinations
thereof.
11. A method of forming an air-permeable composite fabric
comprising the steps of: selecting a vapor barrier from the group
consisting of a membrane and an adhesive, disposing the vapor
barrier between a first fabric layer and a second fabric layer in
order to produce the composite fabric, and mechanically processing
the composite fabric of such that the intermediate, air-permeable
vapor barrier layer has a level of air permeability to allow air
flow between the first fabric layer and the second fabric layer and
the intermediate, air-permeable vapor barrier layer has a variable
level of water vapor diffusion resistance that decreases as air
speed impinging on the composite fabric increases.
12. The method of claim 11, wherein said vapor barrier is a
membrane, and wherein the step of mechanical processing comprises
controlled stretching of the composite fabric.
13. The method of claim 11, wherein said vapor barrier is an
adhesive, and the step of mechanical processing comprises applying
pressure to the composite fabric.
14. The method of claim 13, comprising passing the composite fabric
through a plurality of rollers while applying pressure.
15. The method of claim 13, comprising passing the composite fabric
through a plurality of heated rollers while applying pressure.
16. The method of claim 14 or claim 15, comprising passing the
composite fabric through the rollers at variable controlled
speeds.
17. The method of claim 13, wherein the adhesive is foamed.
18. The method of claim 13, comprising disposing the adhesive
between the first fabric layer and the second fabric layer by
transfer coating using release paper.
19. The method of claim 11, comprising disposing the vapor barrier
between the first fabric layer and the second fabric layer as a
continuous film of adhesive.
20. The method of claim 11, comprising disposing the vapor barrier
between the first fabric layer and the second fabric layer as a
discontinuous film of adhesive.
21. The method of claim 11, comprising disposing the vapor barrier
between the first fabric layer and the second fabric layer as a
film of adhesive using release paper.
22. The method of claim 11, comprising disposing the vapor barrier
between the first fabric layer and the second fabric layer by
applying the adhesive directly to at least one of the first fabric
layer and the second fabric layer.
Description
[0001] This application is a continuation of U.S. application Ser.
No. 09/378,344, filed Aug. 20, 1999, now pending, which claims
benefit from U.S. Provisional Application No. 60/098,254, filed
Aug. 28, 1998, now abandoned. This application is also a
continuation of U.S. application Ser. No. 09/863,852, filed May 23,
2001, now pending, and it is a continuation of U.S. Pat. No.
10/341,309, filed Jan. 13, 2003, now pending, which is a division
of U.S. application Ser. No. 09/863,852, filed May 23, 2001, now
pending.
BACKGROUND
[0002] This invention relates to a fabric material, and more
particularly, to a composite fabric having controlled wind
permeability.
[0003] Conventional composite fabrics are designed to be fully wind
resistant. By way of example, reference is made to U. S. Pat. Nos.
5,204,156; 5,268,212; and 5,364,678, all entitled "Windproof and
Water Resistant Composite Fabric With Barrier Layer," and which
describe a drapable, stretchable, windproof, water resistant and
water vapor-permeable composite fabric. This composite fabric
includes an inner fabric layer 13A, an outer fabric layer 13B, and
a barrier or membrane layer 17A (see FIG. 1). The barrier or
membrane layer is constructed to prevent air and water from passing
through the fabric layers. Testing has shown that the amount of air
flowing through such a composite fabric is on the order or no more
than 1 ft. .sup.3/ft. .sup.2/min.
[0004] The membrane or barrier of this type of prior art fabric
composite is typically adhered or bonded to the fabric layers with
the aid of an adhesive 18. The adhesive can be made from a
polyurethane, polyester, acrylic or polyamide. Reference is made to
FIG. 1, which illustrates the composite fabric of the prior
art.
[0005] The above-described fabric composite is nonetheless less
than desirable. Because such a composite fabric allows only minimal
air flow therethrough, the wearer of the fabric may not be
comfortable. When a person wearing a garment constructed with the
composite fabric of the prior art performs some type of physical
activity, heat is almost always generated, even if the outside air
is cold. In order to adjust for this heat generation, the two
fabric layers may be selected to have low insulative properties.
However, this is disadvantageous, since using such a fabric
composite will cause the wearer to feel cold when no activity is
being performed.
[0006] Another disadvantage with prior art composite fabrics is the
level of moisture vapor transmission. For example, a membrane made
of polytetrafluroethylene, while having a higher moisture vapor
transmission performance than a polyurethane membrane, is still not
desirable, since it cannot handle a situation where high levels of
moisture vapor or sweat are generated. As a result, wearer
discomfort is often prevalent, due to this limitation on moisture
transport. Specifically, excess moisture which could not be
transported out from the fabric condenses next to the skin-side
surface, producing a cold feeling on the skin of the person wearing
a garment made from this type of prior art composite fabric.
[0007] Accordingly, it is desirable to provide an improved
windproof, water vapor permeable fabric which eliminates the
problems associated with prior art fabrics.
SUMMARY
[0008] Generally speaking, in accordance with the invention, a wind
resistant and water vapor permeable composite fabric is provided.
The composite fabric includes an inner fabric layer, an outer
fabric layer, and an intermediate vapor barrier. The vapor barrier
is selected from adhesive material and an adhesive/membrane
combination designed so the composite fabric has a level of air
permeability to allow air flow between the first fabric layer and
the second fabric layer and a variable level of water vapor
diffusion resistance that decreases as air speed impinging on the
composite fabric increases.
[0009] The adhesive may be a continuous film which is mechanically
altered by means of crushing, stretching and the like to enhance
air permeability or a discontinuous film which inherently enhances
air permeability. The adhesive and/or the membrane may be applied
directly to a fabric surface of one or both of the fabric layers or
may be applied by means of transfer coating from release paper.
[0010] In one example, the adhesive functions as a vapor barrier
and is disposed between the two fabric layers. The adhesive may be
in the form of a foam. One or more rollers may be used to apply
pressure to the fabric in order to selectively adjust the air
permeability characteristics thereof.
[0011] In a second embodiment, the vapor barrier comprises a
membrane made from polyurethane, polyamide, polytetrafluroethylene
or polyester, or a combination thereof, which is applied between
the two fabric layers 15 and adhered thereto with an adhesive. The
fabric composite undergoes mechanical processing, such as
controlled stretching, in order to achieve a desired level of air
permeability.
[0012] According to one aspect of the invention, an air-permeable
composite fabric comprises a first fabric layer, a second fabric
layer, and an intermediate, air-permeable vapor barrier disposed
between and bonded to the first and second fabric layers. The
intermediate, air-permeable barrier layer is selected from the
group consisting of: a foamed adhesive in the form of a
discontinuous film, an adhesive in the form of a continuous film
mechanically altered by one of crushing and stretching, and a
membrane disposed between and adhered to the first fabric layer and
the second fabric layer with an adhesive and mechanically altered
by stretching. The intermediate, air-permeable vapor barrier layer
has a level of air permeability to allow air flow between the first
and second fabric layers, and the intermediate, air-permeable vapor
barrier layer has a variable level of water vapor diffusion
resistance that substantially decreases as air speed of moving air
impinging on the fabric increases.
[0013] Preferred embodiments of this aspect of the invention may
include one or more of the following additional features. The
adhesive is selected from the group consisting of polyurethane,
acrylics, polyamides, polyesters and combinations thereof. At least
one of the first and second fabric layers is rendered hydrophilic.
At least one of the first and second fabric layers has a raised
surface. The intermediate, air-permeable vapor barrier comprises an
adhesive selected from the group consisting of: an adhesive in the
form of a mechanically altered continuous film and a foamed
adhesive in the form of a discontinuous film. The vapor barrier is
exclusively foamed adhesive in the form of a discontinuous film.
The intermediate, air-permeable vapor barrier comprises the
membrane disposed between the first and second fabric layers and
adhered thereto with an adhesive and mechanically altered by
stretching, the composite fabric having undergone mechanical
processing. The membrane is made from a material selected from the
group consisting of polyurethane, polyamide,
polytetrafluoroethylene, polyester and combinations thereof. The
mechanical processing comprises controlled stretching. The adhesive
is selected from the group consisting of polyurethane, acrylics,
polyamides, polyesters and combinations thereof.
[0014] According to another aspect of the invention, a method of
forming an air-permeable composite fabric comprising the steps of:
selecting a vapor barrier from the group consisting of a membrane
and an adhesive, disposing the vapor barrier between a first fabric
layer and a second fabric layer in order to produce the composite
fabric, and mechanically processing the composite fabric of such
that the intermediate, air-permeable vapor barrier layer has a
level of air permeability to allow air flow between the first
fabric layer and the second fabric layer and the intermediate,
air-permeable vapor barrier layer has a variable level of water
vapor diffusion resistance that decreases as air speed impinging on
the composite fabric increases.
[0015] Preferred embodiments of this aspect of the invention may
include one or more of the following additional features. The vapor
barrier is a membrane, and the step of mechanical processing
comprises controlled stretching of the composite fabric. The vapor
barrier is an adhesive, and the step of mechanical processing
comprises applying pressure to the composite fabric. The method
comprises passing the composite fabric through a plurality of
rollers while applying pressure. The method comprises passing the
composite fabric through a plurality of heated rollers while
applying pressure. The method comprises passing the composite
fabric through the rollers at variable controlled speeds.
Preferably, the adhesive is foamed. The method comprises disposing
the adhesive between the first fabric layer and the second fabric
layer by transfer coating using release paper. The method comprises
disposing the vapor barrier between the first fabric layer and the
second fabric layer as a continuous film of adhesive. The method
comprises disposing the vapor barrier between the first fabric
layer and the second fabric layer as a discontinuous film of
adhesive. The method comprises disposing the vapor barrier between
the first fabric layer and the second fabric layer as a film of
adhesive using release paper. The method comprises disposing the
vapor barrier between the first fabric layer and the second fabric
layer by applying the adhesive directly to at least one of the
first fabric layer and the second fabric layer.
[0016] Accordingly, it is an object of the invention to provide an
improved windproof composite fabric, whose wind resistance may be
varied.
[0017] Still another object of the invention is to provide a
composite fabric which is water resistant.
[0018] A further object of the invention is to provide an
air-permeable composite fabric.
[0019] Yet another object of the invention is to provide a
composite fabric having a moisture vapor transmission rate which
substantially increases as air speed impinging on the fabric
increases.
[0020] Still other objects and advantages of the invention will in
part be obvious and will in part be apparent from the following
description.
[0021] The invention accordingly comprises the several steps and
the relation of one or more steps with respect to each of the
others, and the fabric possessing the features, properties and
construction of elements which are exemplified in the following
detailed disclosure, and the scope of the invention is indicated in
the claims.
DESCRIPTION OF DRAWINGS
[0022] For a fuller understanding of the invention, reference is
made to the following description, taken in connection with the
accompanying drawings, in which:
[0023] FIG. 1 is a front view in cross-section illustrating a
composite fabric of the prior art;
[0024] FIG. 2 is a front view in cross-section illustrating a
composite fabric made in accordance with the invention;
[0025] FIG. 3A is a graph which shows the change in moisture vapor
transmission as a function of air permeability in the inventive
composite fabric;
[0026] FIG. 3B is a graph showing the change in air permeability as
a function of thermal resistance in the inventive composite
fabric;
[0027] FIG. 4A is a front view in cross-section showing formation
of a second embodiment of the composite fabric of the
invention;
[0028] FIG. 4B shows the effects of controlled stretching on the
composite fabric depicted in FIG. 4A;
[0029] FIG. 5 is a front view in cross-section showing the
formation of a third embodiment of the inventive composite
fabric;
[0030] FIG. 6 is a front elevational view in cross-section showing
the formation of a fourth embodiment of the inventive composite
fabric; and
[0031] FIG. 7 is a graph showing the relationship of water vapor
resistance as a function of wind speed impinging on the inventive
fabric as compared to prior art fabrics.
[0032] Like reference symbols in the various drawings indicate like
elements.
DETAILED DESCRIPTION
[0033] Referring first to FIG. 2, a first embodiment of the
inventive composite fabric, generally indicated at 11, is shown.
Fabric 11 comprises first and second fabric layers 13 and 15, and a
barrier 17 disposed therebetween. Fabric 11 has variable water
vapor permeability, as discussed below. In this embodiment, the
barrier 17 consists of an adhesive material. Adhesive 17 may, in
one form, be applied by means of transfer coating from release
paper at between 0.25 oz/yd.sup.2 and 2.5 oz/yd.sup.2. Each of
layers 13 and 15 may be treated or modified, as described in U.S.
Pat. Nos. 5,204,156; 5,268,212; and 5,364,678, including rendering
the layers hydrophilic, providing the layers with a raised surface,
treating the layers to be water repellant, etc.
[0034] Fabric 11 is formed to any specific controlled wind
resistant performance level, as discussed below. As shown, air
which impinges upon fabric 11 is partially deflected away from the
barrier 17 and partially penetrates as well through the barrier
17.
[0035] In the absence of moving air, water vapor/moisture from the
skin can only transfer through the fabric by means of an
absorption/adsorption phenomenon leading to excess heat buildup and
moisture. When fabric allows some air to pass through the barrier,
it helps in transferring high moisture levels and thus make the
wearer more comfortable.
[0036] Importantly, as wind speed increases, more air flows through
the barrier, allowing more vapor to be dissipated. Thus, the
composite fabric of the invention has a relatively high water vapor
permeability in moving air, and has substantially reduced
resistance to vapor permeability with an increase in air flow. The
reduction in wind resistance or increase in air permeability will
not cause any significant loss of the thermal insulative
properties, as shown in the graphs of FIG. 3A and 3B now discussed,
because the actual amount of air penetrating the barrier is
minimal.
[0037] The graph of FIG. 3A illustrates that for any increase in
air permeability of the inventive fabric, there is a corresponding
decrease in evaporation pressure resistance. The graph of FIG. 3B
shows that for any increase in air permeability of the inventive
fabric, there will be a corresponding decrease in thermal
resistance of the composite fabric. As can be appreciated from
reviewing the graphs, there is a substantial difference between the
magnitude of change in evaporation pressure resistance and thermal
resistance. Evaporation pressure resistance drops far more rapidly
than thermal resistance for the same amount of change in air
permeability of the composite fabric. Thus, when there is a small
increase in air permeability of the composite fabric, the
evaporative pressure resistance reduces significantly. As
evaporation pressure resistance decreases, more moisture can be
transported across the composite fabric, and thus, the loss in
thermal resistance which defines the warmth of the fabric is not
affected significantly.
[0038] FIG. 4A describes a second embodiment of the inventive
composite fabric, which is generally indicated at 21. Composite
fabric 21 includes first and second fabric layers 23 and 25, a
barrier that in this case is an intermediate membrane 27, and an
adhesive 29 on both sides of membrane 27 for adhering membrane 27
to fabric layers 23 and 25. Adhesive 29 may, in one form, be
applied by means of transfer coating from release paper at a
thickness of between 0.25 oz/yd.sup.2 and 2.5 oz/yd.sup.2. Membrane
27 is made from polyurethane, polytetrafluroethyelene or polyester.
Membrane 27 may be applied by means of transfer coating from
release paper at a thickness of between 0.0001 in. and 0.010 in.,
or directly on the fabric surfaces at a thickness of between 0.0003
in. and 0.010 in.
[0039] As shown in FIG. 4B, composite fabric 21 having a width, W,
is subjected to controlled stretching to produce a composite having
a width, W', with a desired specific level of air permeability.
[0040] Referring now to FIG. 5, a third embodiment of the inventive
composite fabric is shown and generally indicated at 31. Composite
fabric 31 includes fabric layers 33 and 35, and a barrier
consisting of an intermediate adhesive 37. The adhesive is chosen
from a polyurethane, polyester, acrylic and polyamide. Here,
adhesive 37 is applied as a foam at between about 0.3 oz/yd.sup.2
and 10 oz/yd.sup.2. The foam density (mixing air with adhesive) and
the amount of adhesive applied are selected depending on the
desired air permeability of the composite. Composite fabric 31 is
prepared by first applying foam adhesive 37 on one of the opposed
surfaces of fabric layers 33 and 35. Once applied, the other fabric
layer is put over the adhesive in order to produce the inventive
fabric composite. Composite 31 is then mechanically processed by
means of a pair of rollers 39, which apply pressure thereto in an
amount between about 10 lbs./in..sup.2 and 150 lbs/in..sup.2 in
order to produce a composite having a specific level of air
permeability.
[0041] Referring now to FIG. 6, a further embodiment of the
inventive composite fabric is shown. Composite fabric 41 comprises
fabric layers 43 and 45 and a barrier formed of an intermediate
adhesive 47. Air permeability is controlled by applying the
adhesive on the fabric and then using some type of mechanical
processing, such as treatment with rollers 19, in order to create
the desired levels of air permeability.
[0042] Still referring to FIG. 6, adhesive 47 may, in one form, be
applied by means of a release paper. The adhesive is first placed
on the release paper at between about 0.25 oz./yd..sup.2 and 2.5
oz./yd..sup.2, after which one of the fabric layers is put on top
thereof in order for bonding to occur. Then, the release paper is
stripped from the fabric and the second fabric layer is applied to
the other side of the adhesive. The composite then undergoes
mechanical processing by rollers 49 (which may be heated to a
temperature of between about 100.degree. F. and 375.degree. F.),
which apply pressure to the composite fabric. As can be
appreciated, changing any mechanical parameter (roller temperature,
pressure applied, and speed of the fabric through the rollers)
helps change the air permeability characteristics of the composite
fabric.
[0043] Alternatively, and still referring to FIG. 6, adhesive 47
may be applied directly to one of fabric layers 43 and 45 (at 0.25
oz./yd..sup.2 to 2.5 oz./yd..sup.2) without the use of release
paper. As before, the composite fabric will undergo mechanical
processing in order to achieve a desired air permeability
performance.
[0044] FIG. 7 describes the advantages of the present invention
over the prior art. In this figure, lines A and B show the water
vapor diffusion resistance for two prior art fabrics (GORE
WINDSTOPPER.RTM. fabric using GORE-TEX.RTM. PTFE membrane from W.
L. Gore & Associates, Inc. (Newark, Del.) and ET551 laminate
with PTFE from Tetratec Corporation (Feasterville, Pa.)). As seen
in FIG. 7, the diffusion resistance for these prior art fabrics is
substantially constant. However, in the materials identified by
lines C, D, E and F, corresponding respectively to various air
permeability level samples (high to low), the vapor diffusion
resistance decreases dramatically with increased wind speed through
the fabric.
[0045] It will thus be seen that the objects set forth above, among
those made apparent from the preceding description, are efficiently
attained, and, since certain changes may be made in carrying out
the above method and in the fabric construction set forth without
departing from the spirit and scope of the invention, it is
intended that all matter contained in the above description and
shown in the drawings shall be interpreted as merely illustrative,
and should not be considered limiting.
[0046] The following claims are intended to cover all of the
generic and specific features of the invention described herein,
and all statements of the scope of the invention which might be
said to fall therebetween.
* * * * *