U.S. patent application number 17/105139 was filed with the patent office on 2021-10-21 for woven multi-layer fabrics for use with non-ballistic threats.
The applicant listed for this patent is Barrday Inc.. Invention is credited to Shekoufeh Shahkarami.
Application Number | 20210324549 17/105139 |
Document ID | / |
Family ID | 1000005681864 |
Filed Date | 2021-10-21 |
United States Patent
Application |
20210324549 |
Kind Code |
A1 |
Shahkarami; Shekoufeh |
October 21, 2021 |
WOVEN MULTI-LAYER FABRICS FOR USE WITH NON-BALLISTIC THREATS
Abstract
A multi-layer woven fabric, including an upper woven layer
having upper warp yarns and upper weft yarns that are interwoven
together to form the upper woven layer. The cover factor of at
least one of the layers is selected so as to inhibit penetration by
non-ballistic threats
Inventors: |
Shahkarami; Shekoufeh;
(Cambridge, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Barrday Inc. |
Cambridge |
|
CA |
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|
Family ID: |
1000005681864 |
Appl. No.: |
17/105139 |
Filed: |
November 25, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16831388 |
Mar 26, 2020 |
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17105139 |
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15036672 |
May 13, 2016 |
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PCT/CA2014/000822 |
Nov 14, 2014 |
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16831388 |
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61904427 |
Nov 14, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F41H 5/0485 20130101;
D03D 13/004 20130101; D03D 13/008 20130101; D03D 11/00 20130101;
D03D 15/43 20210101; D03D 15/567 20210101; D03D 1/0052
20130101 |
International
Class: |
D03D 1/00 20060101
D03D001/00; D03D 13/00 20060101 D03D013/00; F41H 5/04 20060101
F41H005/04; D03D 11/00 20060101 D03D011/00; D03D 15/43 20060101
D03D015/43; D03D 15/567 20060101 D03D015/567 |
Claims
1. A multi-layer woven fabric, comprising: a) an upper woven layer
having upper warp yarns and upper weft yarns that are interwoven
together to form the upper woven layer; b) a lower woven layer
having lower warp yarns and lower weft yarns that are interwoven
together to form the lower woven layer; and c) a plurality of
securing yarns, each securing yarn interwoven with at least some of
the upper yarns and some of the lower yarns so as to secure the
upper and lower woven layers together; d) wherein the multi-layer
ballistic woven fabric is formed by interweaving the securing yarns
with the warp yarns and weft yarns as the upper woven layer and
lower woven layer are made; and e) wherein the cover factor of at
least one of the layers is selected so as to inhibit penetration by
non-ballistic threats.
2. The fabric of claim 1, wherein at least one of the layers has a
cover factor of between 70% and 130%.
3. The fabric of claim 1, wherein both of the layers have a cover
factor of between 70% and 130%.
4. The fabric of claim 1, wherein at least one of the layers has a
cover factor of between 80% and 120%.
5. The fabric of claim 1, wherein both of the layers have a cover
factor of between 80% and 120%.
6. The fabric of claim 1, wherein at least one of the layers has a
cover factor of between 90% and 110%.
7. The fabric of claim 1, wherein both of the layers have a cover
factor of between 90% and 110%.
8. The fabric of claim 1, wherein at least one of the layers has a
cover factor of around 100%.
9. The fabric of claim 1, wherein both of the layers have a cover
factor of around 100%.
10. The fabric of claim 1 wherein at least some of the securing
yarns are made of non-ballistic yarns.
11. The fabric of claim 1 wherein at least some of the securing
yarns are made of ballistic yarns.
12. The fabric of claim 1 wherein at least some of the warp yarns
and weft yarns are made of ballistic yarns.
13. The fabric of claim 1 wherein at least some of the warp yarns
and weft yarns are made of non-ballistic yarns.
14. The fabric of claim 1, wherein the spacing and arrangement of
weaving patterns of the fabric are selected to provide for at least
some protection against non-ballistic threats.
15. The fabric of claim 1, wherein after the fabric has been woven,
the fabric is subjected to a treatment process that shrinks the
securing yarns, drawing the warp yarns and weft yarns towards each
other.
16. The fabric of claim 15, wherein the securing yarns are
encouraged to shrink by up to 1%.
17. The fabric of claim 15, wherein the securing yarns are
encouraged to shrink by up to 3%.
18. The fabric of claim 15, wherein the securing yarns are
encouraged to shrink by up more than 3%.
19. The fabric of claim 15, wherein the securing yarns are
encouraged to shrink by up to 10%.
20. The fabric of claim 1, wherein at least some of the upper weft
yarns and lower weft yarns are offset from each other so as to
overlap by between 30% and 70%.
Description
RELATED APPLICATIONS
[0001] This application is a continuation of and claims the benefit
of priority to U.S. application Ser. No. 16/831,388, filed 26 Mar.
2020, which is a continuation of U.S. application Ser. No.
15/036,672, filed 13 May 2016, which is a U.S. national stage
application filed under 35 U.S.C. .sctn. 371 from International
Application Serial No. PCT/CA2014/000822, which was filed 14 Nov.
2014, and published as WO2015/070331 on 21 May 2015, and which
claims the benefit of U.S. Provisional Patent Application No.
61/904,427 filed Nov. 14, 2013, which applications and publication
are incorporated by reference as if reproduced herein and made a
part hereof in their entirety, and the benefit of priority of each
of which is claimed herein.
TECHNICAL FIELD
[0002] The embodiments herein relate to fabrics, and in particular
to woven fabrics for use in non-ballistic applications.
INTRODUCTION
[0003] Woven fabrics are fabrics in which two distinct sets of
yarns are interwoven with each other to form the fabric. Typically,
woven fabrics include warp yarns that run lengthwise along the
fabric and weft yarns that run across the length of the fabric, and
which are interwoven with and generally perpendicular to the warp
yarns.
[0004] In some ballistic applications, it is desired that two or
more layers of woven fabrics be secured together. Conventionally,
this may be done by providing the woven fabrics separately and then
combining them to produce a multi-layer structure. For example,
various fabric layers may be laid up and then joined together by
resin. However, there are a several disadvantages to this
technique. Firstly, since the woven fabrics are manufactured
separately, this tends to result in higher associated costs.
Furthermore, there may be issues related to the compatibility of
the added resin to the fabric, or various types of ballistic
threats which it might be subject to. Finally, there tend to be
increased labor costs associated with laying up the layers of
fabric.
[0005] In other known fabrics, multiple layers of woven fabric may
be stitched together after being manufactured as separate layers.
However, there tends to be a number of drawbacks with stitching
layers together. Since stitched fabrics use needles that penetrate
through the layers of yarn, gaps may be formed where the stitches
are provided. Furthermore, the penetration of the needles may cause
damage to the yarns. Both of these results are generally
undesirable.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] The drawings included herewith are for illustrating various
examples of articles, methods, and apparatuses of the present
specification and are not intended to limit the scope of what is
taught in any way. In the drawings:
[0007] FIG. 1 is an overhead perspective view of a multi-layer
woven fabric according to one embodiment;
[0008] FIG. 2 is a cross-sectional side view of the multi-layer
woven fabric of FIG. 1;
[0009] FIG. 3A is a photo of a multi-layer fabric according to
another embodiment;
[0010] FIG. 3B is a close-up view of the photo of FIG. 3A;
[0011] FIG. 4 is a photo of a multi-layer fabric according to yet
another embodiment having an offset weave;
[0012] FIG. 5 is a flowchart illustrating a method of manufacturing
a woven multi-layer fabric according to another embodiment;
[0013] FIG. 6 is a cross-sectional side view of a multi-layer
fabric having an offset weave according to another embodiment;
[0014] FIG. 7 is a cross-sectional side view of a multi-layer
fabric having an offset weave according to another embodiment;
[0015] FIG. 8 is a photo of a multi-layer fabric having a plain
weave and satin weave checker pattern according to yet another
embodiment;
[0016] FIG. 9 is a photo of a multi-layer fabric having a plain
weave and satin weave checker pattern according to yet another
embodiment;
[0017] FIG. 10 is a photo of a multi-layer fabric having a plain
weave (the bottom layer) and satin weave (the top layer) according
to yet another embodiment;
[0018] FIG. 11 is a photo of a multi-layer fabric having a plain
weave (the top layer) and satin weave (the bottom layer) according
to yet another embodiment; and
[0019] FIG. 12 is a photo of a multi-layer fabric having two satin
weave layers according to yet another embodiment.
DETAILED DESCRIPTION
[0020] Generally illustrated in FIGS. 1 and 2 is a multi-layer
fabric 10 according to one embodiment.
[0021] The fabric 10 has a first (or upper) woven layer indicated
generally as 11. The upper woven layer 11 includes first (or upper)
warp yarns 12 and first (or upper) weft yarns 14 (e.g. 14a, 14b,
14c, 14d) that are interwoven together to form the first or upper
woven layer 11. The first warp yarns 12 and first weft yarns 14 in
the upper woven layer 11 are crimped, in the sense that each first
yarn 12, 14 is bent around the other first yarns 12, 14 at
crossover points or nodes to provide an interlocking or interwoven
structure.
[0022] The fabric 10 also has a second (or lower) woven layer
indicated generally as 13. The lower woven layer 13 includes second
(or lower) warp yarns 15 and second (or lower) weft yarns 17 (e.g.
17a, 17b, 17c, 17d) that are interwoven together to form the second
or lower woven layer 13. The second warp yarns 15 and second weft
yarns 17 in the second layer 13 are crimped, in the sense that each
second yarn 15, 17 is bent around the other yarns 15, 17 at
crossover points or nodes to provide an interwoven structure.
[0023] It will be appreciated that the terms "upper" and "lower" as
used herein are used for convenience only, and the actual relative
positions of the first or upper woven layer 11 and the second or
lower woven layer 13 may be varied.
[0024] Generally the yarns of one layer are not interwoven with the
yarns of another layer because such interweaving tends to increase
the degree of crimp for the yarn in relation to rest of the yarns
in the fabric, which can create ballistic weak points. In
particular, the first or upper yarns 12, 14 are not interwoven with
the second or lower yarns 15, 17, and vice versa. Instead, as
shown, the first or upper layer 11 and second or lower layer 13 are
secured together by one or more securing yarns 22. The securing
yarns 22 are interwoven with at least some of the upper yarns 12,
14 and some of the lower yarns 15, 17 so as to secure the upper and
lower layers 11, 13 together.
[0025] The securing yarns 22 generally form part of the woven
fabric 10. In particular, the woven fabric 10 is formed by
interweaving the securing yarns 22 with the warp yarns 12, 15 and
weft yarns 14, 17 as the fabric 10 is formed. Therefore, the upper
and lower woven layers 11, 13 can be secured together without the
need for stitching, resin or other mechanisms to join the woven
layers 11, 13 together.
[0026] In this manner, a fabric 10 having two (or more) woven
layers 11, 13 can be manufactured as a unified construction,
without the need for joining two different fabric layers together
after being formed individually.
[0027] Manufacturing the fabric as a unified construction also
tends to provide a lower crimp level for each layer, which tends to
maintain or improve potential ballistic performance of the
individual layers while achieving additional advantages associated
with securing the layers together, such as higher integrity,
enhanced trauma and overall ballistic performance as well as
manufacturing advantages.
[0028] As shown, in some embodiments the securing yarns 22 may be
aligned with the warp or weft yarns. For example, the securing
yarns 22 may be generally parallel to or aligned with the warp
yarns 12, 15 and generally perpendicular to the weft yarns 14, 17.
In other embodiments, the securing yarns 22 may be generally
parallel to or aligned with the weft yarns 14, 17 and generally
perpendicular to the warp yarns 12, 15. In yet other embodiments
(e.g. as shown in FIG. 3), securing yarns 22 may be provided in
both the warp and weft directions (e.g. in a checker pattern) with
at least some securing yarns 22 parallel to the warp yarns 12, 15
while at least some other securing yarns 22 are parallel to the
weft yarns 14, 17.
[0029] Turning now specifically to FIG. 2, illustrated therein is a
cross-sectional side view of the woven multi-layer fabric 10. As
shown, (from left to right on FIG. 2) one of the securing yarns 22
extends from above the upper layer 11 and passes underneath a first
lower weft yarn 17a (of the lower weft yarns 17), then over a
second upper weft yarn 14b (of the upper weft yarns 14, and
generally next to or adjacent the first lower weft yarn 17a), then
underneath a third lower weft yarn 17c (generally next to or
adjacent the second upper weft yarn 14b), and then above a fourth
upper weft yarn 14d (generally next to or adjacent the third lower
weft yarn 17c) and then extends below the lower layer 13. In this
manner the securing yarn 22 tends to secure the upper weft yarns 14
and the lower weft yarns 17 together, thus joining the first woven
layer 11 and the second woven layer 13.
[0030] While the illustrated embodiment shows a securing yarn
extending over and under one weft yarn at a time, in other
embodiments, the securing yarns may extend over or under more than
one weft yarn at a time. For example, the securing yarns may be
woven underneath two weft yarns, and then above five upper weft
yarns adjacent the lower weft yarns. Accordingly, the securing
yarns may be woven underneath at least one lower weft yarn, and
then above at least one upper weft yarn adjacent the at least one
lower weft yarn.
[0031] In some embodiments, one or more of the warp yarns 12, 15
and/or weft yarns 14, 17 could be used in addition to, or in place
of, one or more securing yarns 22 for holding the two or more
layers together. For example, one or more the of the warp yarns 12,
15 and/or the weft yarns 14, 17 could be interwoven along a path
similar to the path of the securing yarn 22 as shown in FIG. 2 to
secure the first layer 11 to the second layer 13.
[0032] Each of the warp yarns 12, 15 and weft yarns 14, 17 and
securing yarns 22 may include a plurality of fibers or filaments of
one or more materials as will be described in greater detail
below.
[0033] In some embodiments, the selection and arrangement of the
securing yarns 22 may be varied to obtain desired performance of
the fabric 10. For example, the size, ratio and/or spacing of
securing yarns 22 may be different in different embodiments of the
fabric 10.
[0034] In some embodiments, a plurality of securing yarns 22 could
be spaced apart from each other by a distance of between one inch
and three inches. In other embodiments, securing yarns 22 may be
spaced apart by a distance of less than one inch. In yet other
embodiments, securing yarns may be spaced apart by a distance of
more than three inches.
[0035] The ratio between securing yarns 22 and ballistic yarns
(e.g. warp yarns 12, 15 and weft yarns 14, 17) as well as the
spacing therebetween tends to depend on the desired inter-layer
stability (e.g. providing more securing yarns 22 and/or providing
securing yarns 22 spaced closer together tend to result in a more
stable fabric 10) versus the degree of interference between the
woven layers 11, 13 (e.g. more securing yarns 22 tend to result in
the woven portions deviating more from a conventional woven fabric,
e.g. which may cause more distortion between the woven fabric
layers).
[0036] In some embodiments, the securing yarns 22 are made from a
high elongation yarn, a low strength, and/or a low modulus yarn, as
generally described below.
[0037] In some embodiments, the warp yarns 12, 15 and weft yarns
14, 17 are ballistic yarns. For example, the warp yarns 12, 15 and
weft yarns 14, 17 may be ballistic yarns having a tenacity of about
15 grams per denier and higher, and with a tensile modulus of at
least about 400 grams per denier.
[0038] Some examples of suitable yarns could include carbon, basalt
and glass fibers. Other examples include aramid and copolymer
aramid fibers (produced commercially by DuPont and Teijin under the
trade names Kevlar.RTM., Twaron.RTM., and Technora.RTM.), extended
chain polyethylene fibers (produced commercially by Honeywell, and
DSM, under the trade names Spectra.RTM., and Dyneema.RTM.),
polyethylene fibers and films produced by Synthetic Industries and
sold under the trade name Tensylon.RTM.,
poly(p-phenylene-2,6-benzobisoxa-zole) (PBO) (produced by Toyobo
under the commercial name Zylon.RTM.), and Liquid crystal polymers
produced by Kuraray under the trade name Vectran.RTM.. Other
suitable yarns may also be used.
[0039] In some embodiments, the securing yarns 22 are generally of
significantly smaller denier than the warp yarns 12, 15 and/or weft
yarns 14, 17 and may have significantly lower tenacities and
tensile moduli. As a result, the securing yarns 22 tend to greatly
reduce or eliminate undesirable deflection or distortion of the
first and second layers 11, 13. In particular, the securing yarn 22
may be substantially crimped while it may be desirable to have the
layers 11, 13 be as flat as possible.
[0040] In some examples, the securing yarns 22 have a tenacity of
less than about 10 grams per denier, and a tensile modulus of less
than about 40 grams per denier. In one example, the securing yarns
22 are made of a 78 dtex Nylon, while the warp yarns 12, 15 and
weft yarns 14, 17 may be made of a 3000 denier aramid (e.g.
Kevlar.RTM.).
[0041] In some examples, the denier of the securing yarns 22 may
range from between about 20 denier (or less), to about 1000 denier,
depending on the size of the warp yarns 12, 15 and weft yarns 14,
17, and the desired ballistic applications.
[0042] In some alternative examples, the same yarn that is used in
the woven body of either fabric layer may be used as a securing
yarn to tie the two or more layers of fabric together (i.e., the
warp and/or weft yarns could be used as securing yarns).
[0043] In some embodiments, the securing yarns 22 may be generally
of a much smaller size than the warp yarns 12, 15 and weft yarns
14, 17. The diameter of the securing yarns 22 may be selected based
on the moduli and strength parameters of the securing yarns 22. In
some embodiments, where the securing yarns 22 are made of
non-ballistic yarns (e.g. Nylon, etc.), it may be desirable that
the securing yarns 22 be high elongation yarns that are as stretchy
as possible and as small as possible.
[0044] In some examples, the securing yarns 22 may be selected from
a wide range of fibers. Some suitable example fibers include
natural fibers, such as cotton, wool, sisal, linen, jute and silk.
Other suitable fibers include manmade or synthetic fibers and
filaments, such as regenerated cellulose, rayon, polynosic rayon
and cellulose esters, synthetic fibers and filaments, such as
acrylics, polyacrylonitrile, modacrylics such as
acrylonitrile-vinyl chloride copolymers, polyamides, for example,
polyhexamethylene adipamide (nylon 66), polycaproamide (nylon 6),
polyundecanoamide (nylon 11), polyolefin, for example, polyethylene
and polypropylene, polyester, for example, polyethylene
terephthalate, rubber and synthetic rubber and saran. Glass, carbon
or any other high performance fiber may also be used.
[0045] Staple yarns may also be used and may include any of the
above fibers, low denier staple yarns or any combination of these
yarns. Staple yarns, by the discontinuous nature of their filaments
that form the yarn, tend to have much lower tensile and modulus
properties as opposed to yarns composed of continuous
filaments.
[0046] The performance of the fabric 10 is generally a function of
the properties of the securing yarns 22 and the warp yarns 12, 15
and weft yarns 14, 17. In ballistic fabrics, maximizing the amount
of the ballistic fibres (e.g. the warp yarns 12, 15 and the weft
yarns 14, 17) in a given volume tends to be beneficial, as higher
fibre to volume ratio fraction generally signifies improved
ballistic properties. Therefore, in some examples it may be
desirable that the securing yarns 22 have a denier that is as low
as practical while still being able to weave the fabric 10.
[0047] In the fabric 10, it may be desirable to minimize the weight
of the securing yarns 22 as a percentage of the total weight of the
fabric 10, since the securing yarns 22 may not contribute as much
to the strength of the fabric 10 as the ballistic yarns (e.g. the
warp yarns 12, 15 and the weft yarns 14, 17). Conversely, an
increased quantity of securing yarns 22 may result in a more
durable, stable fabric 10; however, the fabric 10 may tend to be
heavier.
[0048] In some examples, the securing yarns 22 may be selected to
have the lowest denier, and the lowest strength as practical that
can be woven between the layers, and that satisfy the requirements
for a particular ballistic application.
[0049] In some embodiments, two or more fabrics 10 may be joined
together to form a ballistic member having four or more woven
layers (e.g. two fabrics 10 may be joined using a resin, film or
other suitable techniques to form a fabric that has four woven
layers).
[0050] The fabric 10 may also be fabricated into a prepreg using a
film or a wet resin. Depending on the application, the film or
resin may be applied to one side of the fabric 10, the fabric 10
may be totally impregnated with a resin, or the film may be worked
into the fabric 10. In some examples, the film or resin may be a
thermoplastic or a thermoset resin. Generally, any resin or film
that can be used to create a prepreg may be used with this fabric
10. In some embodiments, two or more layers of fabric 10 may be
laminated together to further increase the number of layers.
[0051] In some embodiments, three or more woven layers may be
secured together to form a fabric using one or more securing yarns
that are interwoven as the fabric is being made.
[0052] Turning now to FIGS. 3A and 3B, illustrated therein is a
fabric 110 according to another embodiment. The fabric 110 has a
first woven layer 111 (e.g. having first interwoven warp and weft
yarns) and a second woven layer 113 (e.g. having second interwoven
warp and weft yarns). The first and second layers 111, 113 are
secured together by securing yarns 122 that are interwoven with the
first and second warp and weft yarns as the fabric 110 is woven
together.
[0053] Referring now to the close up of FIG. 3B, the fabric 110 is
being pulled apart to reveal the securing yarns 122 in more detail.
In particular, first securing yarns 122a are oriented in a first
direction (e.g. the warp direction) while second securing yarns
122b are oriented in a second direction (e.g. the weft
direction).
[0054] In one exemplary embodiment, a multi-layer woven fabric
according to FIGS. 3A and 3B was created and tested in a ballistic
9 mm V50 test. In particular, a woven multi-layer fabric as
generally described herein made of 3360 dtex aramid was compared to
a traditional fabric with separate layers laminated together using
a resin. The V50 ballistic test for these fabrics were conducted in
a standard setting for a 16''.times.16'' pack using a 9 mm
Remington and at 0.75 lb/ft2 for both samples, with the following
results:
TABLE-US-00001 Fabric Areal Product Density Ballistic Pack Areal
Density Ballistic 9 mm V50 Description Dry (g/m2) lb/ft2 Kg/m2 ft/s
m/s Conventional Aramid 606 0.75 3.64 1112 339 3360 dtex 1 .times.
1 Plain, 2 layer laminate New Woven Multi-layer 1212 0.75 3.64 1125
343 Aramid 3360 dtex 2 L Plain, 2 layer laminate
[0055] As shown, the woven multi-layer fabric tends to provide
similar performance as a conventional fabric while providing at
least some of the advantages as generally described herein. For
example, the new multi-layer fabric has gone through about half the
number of processing steps in comparison to the conventional
fabric, which is advantageous for both performance and cost.
[0056] In some embodiments, the multi-layer fabric might be used
with a resin. If the fabric has high adhesion to the resin, the
securing yarn can dissipate energy by breaking during the ballistic
event while the resin keeps the other layers together and prevents
trauma.
[0057] Turning now to FIG. 4, illustrated therein is a fabric 210
according to another embodiment in which the fabric 210 has an
offset weave. In particular, the fabric 210 has two separate
layers: namely a first or upper layer 211 and a second or lower
layer (not shown). In this fabric 210, the upper and lower warps
and wefts are offset. In particular, the upper warp yarns are not
sitting on top of the lower warp yarns, but rather are sitting
beside each other (e.g. are at least slightly offset), and the
upper weft yarns are not sitting on top of the lower weft yarns,
but rather are sitting beside each other (e.g. are at least
slightly offset). This offset weave generally provides the fabric
210 with more room to spread out, resulting is less squishing or
crimping of the fabric 210.
[0058] The offset design also tends to improve ballistic
performance by reducing the number and/or size of openings between
yarns in the fabric because the yarns of one layer cover openings
in the adjacent layer, as described below.
[0059] In some ballistic applications, it is sometimes desirable to
lower the cover factor of the fabric (e.g. by spacing apart yarns
and providing openings therebetween) in order to increase the
number of fabric layers in a pack for a given areal density. The
increased number of fabric layers tends to enhance the ballistic
V50 performance. However, there is a limit to the increase in
performance because having a cover factor that is too low results
in an open construction, which tends to increase the bullet
penetration during a ballistic event and hence lowers the ballistic
resistance. The offset design described above tends to enhance
ballistic performance for a given yarn size and ballistic areal
density by providing the layering effect while covering the
openings in each layer with the yarns of the adjacent layer as the
two layers are interwoven in an offset layering pattern.
[0060] In some embodiments, some of the warp yarns and/or weft
yarns may at least partially overlap, which the inventor believes
may tend to increase the ballistic performance.
[0061] As shown, the first layer 211 and second layer are secured
together by a plurality of first securing yarns 222a and a
plurality of second 222b (generally similar to the securing yarns
22 as described above) that are generally perpendicular to each
other and which are arranged in an array or pattern. For example,
the first securing yarns 222a may be oriented in a first direction
(e.g. the warp direction), while the second securing yarns 222b may
be oriented in a second direction (e.g. the weft direction).
[0062] As shown, the first securing yarns 222a may be separated
from each other by a first spacing T, while the second securing
yarns 222b may be separated from each other by a second spacing S.
The first and second spacings T, S may be similar or different.
Generally, the spacings T, S may be selected so as to obtain
desired properties for the fabric 210.
[0063] In some embodiments, the first spacing T may be between one
inch and three inches. In other embodiments, the first spacing T
may be less than one inch, or more than three inches.
[0064] In some embodiments, the second spacing S may be between one
inch and three inches. In other embodiments, the second spacing S
may be less than one inch, or more than three inches.
[0065] In some embodiments, the layers of fabric may be secured
using securing yarns that extend in only one direction (e.g. the
weft direction only).
[0066] Turning now to FIG. 5, illustrated therein is a method 100
of forming a multi-layer woven fabric according to one
embodiment.
[0067] At step 102, warp yarns are provided. For example, first
warp yarns 12 and second warp yarns 15 may be provided on a loom or
weaving machine (e.g. standard 2D weaving looms, including rapier,
shuttle, air jet and water jet looms).
[0068] At step 104, weft yarns are interwoven with the warp yarns
to form at least two woven layers (e.g. a first woven layer and a
second woven layer). For example, the first weft yarns 14 could be
interwoven with the first warp yarns 12 by alternatively moving the
first warp yarns 12 up and down and passing a shuttle with the
first weft yarns 14 therebetween, as will generally be understood.
Similarly, the second warp yarns 15 could be interwoven with the
second weft yarns 17 to form the second woven layer 13.
[0069] At step 106, the securing yarns are interwoven with the warp
yarns and/or the weft yarns as the fabric is being made (e.g. as
the weft yarns and warp yarns are being woven together) to secure
the first and second woven layers together. For example, the
securing yarns 22 may be alternatively interwoven with the first
and second warp yarns 12, 15 by selectively moving the warp yarns
12, 15 up and down and passing a shuttle with the securing yarns 22
therethrough as the warp yarns 12, 15 and weft yarns 15, 17 are
being woven together.
[0070] It will be appreciated that the steps 102, 104 and 106 of
the method 110 generally do not have to be done in a specific order
and that the order as listed is in no way meant to be limiting.
[0071] Turning now to FIG. 6, illustrated therein is another fabric
310 according to another embodiment having an upper layer 311 that
is offset from the lower layer 313. For example, the fabric 310 may
be similar to the fabric 210 described previously.
[0072] The upper woven layer 311 includes warp yarns 312 and upper
weft yarns 314 (e.g. 314a, 314b, 314c, 314d) that are interwoven
together to form the first or upper woven layer 311. The lower
woven layer 313 includes lower warp yarns 315 and lower weft yarns
317 (e.g. 317a, 317b, 317c, 317d) that are interwoven together to
form the second or lower woven layer 313. The upper and lower woven
layers 311, 313 are secured together using one or more securing
yarns 322 generally as described previously.
[0073] As shown, the upper weft yarns 314 and lower weft yarns 317
are offset so that, for example, the first upper weft yarn 314a
overlaps the first lower weft yarn 317a by an overlap amount P.
Accordingly, the securing yarn 322 tends to be less crimped and
more spread out (as compared to the more compact path of the
securing yarn 22 described above).
[0074] In some embodiments, the overlap amount P is between 10% and
95%. In other embodiments, the overlap amount P is between 30% and
70%. In other embodiments, the overlap amount is around 50%.
[0075] Turning now to FIG. 7, illustrated therein is a fabric 410
according to yet another embodiment. Fabric 410 has an upper layer
411 that is offset from the lower layer 413.
[0076] The upper woven layer 411 includes warp yarns 412 and upper
weft yarns 414 (e.g. 414a, 414b, 414c, 414d) that are interwoven
together to form the first or upper woven layer 411. The lower
woven layer 413 includes lower warp yarns 415 and lower weft yarns
417 (e.g. 417a, 417b, 417c, 417d) that are interwoven together to
form the second or lower woven layer 413. The upper and lower woven
layers 411, 413 are secured together using one or more securing
yarns 422 generally as described above.
[0077] As shown, the upper weft yarns 414 and lower weft yarns 417
are offset similar to the fabric 310, so that, for example, the
first upper weft yarn 414a overlaps the first lower weft yarn 417a
by an overlap amount P. In this embodiment, the upper weft yarns
414 and lower weft yarns 417 are generally more evenly spaced apart
by the overlap distance P.
[0078] Turning now to FIG. 8, illustrated therein is a multi-lawyer
woven fabric 510 according to another embodiment. The fabric 510
generally includes an upper woven layer 511 and lower woven layer
513 secured together using first securing yarns 522a and second
securing yarns 522b generally as described previously. In this
embodiment, the upper woven layer 511 and lower woven layer 513
each have a "checkered" pattern made up of adjacent plain woven
portions 525 (e.g. portions of the layers 511, 513 with a plain
weave) and satin woven portions 527 (e.g. portions of the layers
511, 513 with a satin weave). These types of woven layers may be
referred to as Platin.TM. and are described more generally in PCT
International Patent Application Publication Numbers WO2009153120
and WO2009153121.
[0079] In this embodiment, the plain woven portions 525 and satin
woven portions of the upper and lower layers 511, 513 are aligned.
For example, as shown a first plain woven portion 525a on the upper
layer 511 is aligned with and positioned above a second plain woven
portion 525b on the lower layer.
[0080] Turning now to FIG. 9 illustrated therein is a multi-lawyer
woven fabric 610 according to another embodiment. The fabric 610 is
similar to fabric 510 and generally includes an upper woven layer
611 and lower woven layer 613 secured together using first securing
yarns 622a and second securing yarns 622b generally as described
previously. However, in this embodiments the "checked" plain woven
and satin portions are staggered with respect to each other. For
example, as shown a first plain woven portion 625a on the upper
layer 611 is aligned with and positioned above a second satin woven
portion 627b on the lower layer 613.
[0081] While the embodiments of FIGS. 8 and 9 have Platin.TM.
layers arranged so that the woven portions and satin portions are
either matching or opposite, in some embodiments, the Platin.TM.
layers may be arranged in a random design such that the woven
portions and satin portions of each layer are offset from each
other, opposed to being aligned in either matching or opposite
patterns.
[0082] Multi-layer woven fabrics made with Platin.TM., and as
described above, were created and tested in a ballistic 9 mm V50
test, with the following results:
TABLE-US-00002 Product Ballistic Pack Areal Density Ballistic 9 mm
V50 Description lb/ft2 Kg/m2 ft/s m/s 2 layer Platin with 1.1 5.4
1505 459 matching patterns 2 layer Platin with 1.1 5.4 1496 456
opposite patterns 2 layer Platin with 1.1 5.4 1470 448 random
design
[0083] As show, the performance of the 2 layer Platin fabric with
matching patterns performed better than the other two fabrics.
[0084] In another exemplary embodiment, a multi-layer woven fabric
with offset woven layers was created and tested in a ballistic 9 mm
test as well as a 0.22 CAL 17 grain FSP test and compared to a
plain fabric. The offset woven layers were secured together using
securing yarns aligned with the weft yarns only. The securing yarns
were spaced separated by a spacing of about a 1/4 of an inch. The
ballistic tests for these fabrics were conducted in a standard
setting for a 16''.times.16'' pack using a 9 mm Remington and a
0.22 CAL FSP at an areal density of 1.1 lb/ft2 for both samples,
with the following results:
TABLE-US-00003 Areal Areal Density Fabric, all Density (of (of the
greige, aramid # of the layer) pack) 17 grain 9 mm 930 dtex layers
g/m.sup.2 Psf @1.1 psf @1.1 psf Offset 23 233 1.10 654 521 Plain
Fabric 26 207 1.11 622 502
[0085] The performance in the 9 mm and 0.22 CAL FSP tests were both
improved. Furthermore, the performance in the 0.22 CAL FSP test was
improved with the offset fabric by 33 feet, an increase of
approximately 5.3%.
[0086] The new fabric with offset woven layers had a higher
performance in both tests with fewer layers of fabric. This is
despite the conventional understanding that a fabric having a lower
cover factor and more layers of fabric for a given areal density
should perform better. The inventor believes that the increased
performance is due to the offset design, in which the coverage for
each yarn within the fabric structure is maximized by having each
direction yarn (warp or weft) sitting at two levels with
overlaps.
[0087] While the exemplary embodiment tested utilized securing
yarns aligned with the weft yarns and spaced apart by about a 1/4
of an inch, in other embodiments, the securing yarns may be aligned
with the warp yarns and/or the weft yarns, and may be separated by
a spacing of less than three inches.
Additional Example
[0088] According to another example, a multilayer fabric was woven
at about 100% cover factor for each of the layers in a two layer
woven fabric. The fabric yarn size was 550 dtex, which is higher
than yarn sizes commonly used in spike protection.
[0089] Lower yarn sizes tend to be advantageous is spike
resistance. In particular, spike resistance tends to deteriorate as
the yarn sizes increase to a point that the weight disadvantage of
additional fabric layers for higher denier yarns prohibits the
viability of the product from both a weight and cost point of
view.
[0090] However, in this example, the 550 dtex yarn size (which is
not a common yarn size used in traditional spike applications) was
explored and made into a woven fabric according to the teachings
herein. The scoured fabric layers were then tested at Barrday's
internal lab and in accordance with the `National Institute of
Justice (NIJ) Standard 0115.00-Stab Resistance of Personal Body
Armor`. These test protocols and test conditions are defined in the
NIJ spec, as well as the definitions for various energy levels.
[0091] The following table summarizes the test results for this
fabric, and indicate that this fabric is a viable solution for
spike resistance even though it is at a higher yarn size of 550
dtex.
TABLE-US-00004 NIJ Spike Description Dry W level Layer# AD(psf) 550
dtex 400 L1E2 4 0.33 SOS45 L2E2 6 0.49 L3E2 6 0.49 NIJ test results
for 550 dtex
[0092] The fabrics described herein may generally be used in any
combination with the materials listed above and may replace any one
material or combination of materials in an existing ballistic
fabric. In addition, the fabrics described herein may be laminated
together or laminated with films to produce ballistic elements for
various applications, including soft armor applications, hard armor
applications, and rigid and/or semi-rigid applications. The
proportions of each material selected and the design of the
ballistic elements may vary depending on the intended application
(i.e. particular specifications for military or police
applications).
[0093] Generally, the multi-layer fabrics described herein utilize
a unique technique to secure fabric layers together and limit the
use of extra stitching and resin application unless desired for
providing particular properties.
[0094] Turning now to FIG. 10, illustrated therein is a multi-layer
fabric having a plain weave (the bottom layer) and satin weave (the
top layer) according to yet another embodiment.
[0095] Similarly, FIG. 11 shows a multi-layer fabric having a plain
weave (the top layer) and satin weave (the bottom layer) according
to yet another embodiment.
[0096] Lastly, FIG. 12 shows a multi-layer fabric having two satin
weave layers according to yet another embodiment.
[0097] In some embodiments, one or more woven multi-layer fabrics
as generally described herein may be suitable for other types of
threats, such as stab or spike threats. For example, some woven
multi-layer fabrics may be suitable against stab or spike threats
in addition to (or as an alternative to) being effective against
ballistic threats.
[0098] In particular, there is a need, especially in fields like
law enforcement and for use in correctional facilities (i.e.,
jails, prisons, etc.), for protective clothing that provides some
protection for a wearer against penetration of a variety of
dangerous instruments, such as blades, picks, shanks, awls, and the
like.
[0099] Some protective clothing is designed to be resistant to
either stabbing materials (i.e., ice picks, knives and the like),
or ballistic threats, but not both. In some circumstances, however,
it may not be practical or safe to be protected from only one of
these threats. Nor may it be practical to wear multiple layers of
protective wear, with each individual layer is designed for a
different threat, since this may be bulky or uncomfortable.
[0100] Several known approaches to protect against both stabbing
and ballistic threats are problematic. One typical prior art
approach is to simply add stab resistant materials to ballistic
resistant fabrics. For example, a stab resistant metal sheet (such
as a titanium sheet) could simply be secured to a ballistic
resistant fabric. However, such constructions tend to be bulky and
may be uncomfortable to the point of being impractical.
[0101] According to some embodiments as described herein, at least
some level of protection against non-ballistic threats may be
provided by some woven multi-layer fabrics. For instance, the
properties of the woven multi-layer fabric (i.e. yarn types) as
well as the spacing and arrangement of weaving patterns may be
selected to provide for at least some protection against stab
and/or spike threats.
[0102] In some cases, these same fabrics may also provide for
ballistic protection, although this is not necessarily required. In
some examples, the securing yarns may be made of non-ballistic
yarns (i.e., Nylon), while the warp yarns and weft yarns may be
made of aramid (e.g. Kevlar.RTM.). In other examples, the securing
yarns and the warp yarns and weft yarns may be made of any suitable
combination of ballistic or non-ballistic yarns.
[0103] In some embodiments, the cover factor of each layer of the
woven multi-layer fabric may be selected so as to inhibit
penetration by non-ballistic threats, such as spikes and blades.
For example, in one embodiment, a woven multi-layer fabric may be
provided which has a cover factor between 70% and 130% for at least
one of the layers of fabric. In another embodiment, a woven
multi-layer fabric may be provided which has a cover factor between
80% and 120% for at least one of the layers of fabric. In another
embodiment, a woven multi-layer fabric may be provided which has a
cover factor between 90% and 110% for at least one of the layers of
fabric. In yet another embodiment, a woven multi-layer fabric may
be provided which has a cover factor around 100% for at least one
of the layers of fabric. In yet other embodiments, both layers of a
woven multi-layer fabric with two layers will have a cover factor
of between 90 and 110%.
[0104] Selecting a cover factor in this manner will tend to
encourage penetration resistance of the fabric.
[0105] In some embodiments, the desired cover factor might be
achieved according to particular weaving patterns and
techniques.
[0106] In some embodiments, the properties of the yarns and/or
processes applied to the fabric could be selected to promote a
desired cover factor for each layer. For instance, in some
embodiments, after the fabric has been woven, the fabric could be
subjected to a treatment process that encourages the securing yarns
to shrink, which tends to draw the warp and weft yarns toward each
other|the woven multi-layer fabric, thus encouraging higher cover
factors.
[0107] In one specific example, securing yarns could be encouraged
to shrink by up to 1%, up to 3%, more than 3%, or even up to
10%.
[0108] In some embodiments, once a woven multi-layer fabric has
been woven, the fabric may be subjected to a process to increase
the penetration resistance of the fabric. For example, this may be
done by densifying the fabric, in some cases through a minimum of
at least about 1% shrinkage. Shrinkage of the fabric during
densification tends to engage a greater number of fibers in a
particular area and increase the penetration resistance of the
fabric.
[0109] In other cases, penetration resistance may be increased by
fibrillating the yarns of the fabric, or using other
techniques.
[0110] As described in detail above, in some embodiments, some of
the warp yarns and/or weft yarns of the different layers of a woven
multi-layer fabric may at least partially overlap. In some
embodiments, the overlap amount P of the woven multi-layer fabric
may be selected so as encourage penetration resistance to
non-ballistic threats. For example, the overlap amount P may be
between 10% and 95%. In other embodiments, the overlap amount P is
between 30% and 70%. In other embodiments, the overlap amount is
around 50%.
[0111] In some embodiments that may be well suited for
non-ballistic threats, the overlap amount P may be between about 90
and 95%. In some other embodiments that may be well suited for
non-ballistic threats, the overlap amount P may be above 95%. In
some further embodiments, the overlap amount P may be above 98%, or
even 99%, or even approaching (or at) 100%.
[0112] Configuring the woven multi-layer fabrics in this manner
(i.e., adjusting the cover factor of the layers and/or the overlap
amount P) may allow certain fabrics to be effective against
non-ballistic threats. Moreover, some of these fabrics may be
effective against both ballistic and non-ballistic threats, making
them "multi-threat" fabrics.
[0113] While the above description provides examples of one or more
fabrics, processes or apparatuses, it will be appreciated that
other fabrics, processes or apparatuses may be within the scope of
the present description as interpreted by one of skill in the
art.
* * * * *