U.S. patent application number 11/396153 was filed with the patent office on 2011-03-24 for liquid submersion ballistic performance through hybridization.
This patent application is currently assigned to Honeywell International Inc.. Invention is credited to Henry G. Ardiff, Brian D. Arvidson, Ashok Bhatnagar, David A. Hurst.
Application Number | 20110067560 11/396153 |
Document ID | / |
Family ID | 39314884 |
Filed Date | 2011-03-24 |
United States Patent
Application |
20110067560 |
Kind Code |
A1 |
Hurst; David A. ; et
al. |
March 24, 2011 |
LIQUID SUBMERSION BALLISTIC PERFORMANCE THROUGH HYBRIDIZATION
Abstract
Ballistic resistant articles having excellent resistance to
deterioration due to liquid exposure. More particularly, a
ballistic resistant structures and articles formed from a hybrid of
woven and non-woven fibrous components that retain their superior
ballistic resistance performance after exposure to liquids such as
sea water and organic solvents, such as gasoline and other
petroleum-based products. The hybrid structures are particularly
useful for the formation of or for use in conjunction with soft,
flexible body armor.
Inventors: |
Hurst; David A.; (Richmond,
VA) ; Arvidson; Brian D.; (Chester, VA) ;
Bhatnagar; Ashok; (Richmond, VA) ; Ardiff; Henry
G.; (Chesterfield, VA) |
Assignee: |
Honeywell International
Inc.
|
Family ID: |
39314884 |
Appl. No.: |
11/396153 |
Filed: |
March 31, 2006 |
Current U.S.
Class: |
89/36.02 ;
156/148; 89/904; 89/914; 89/915 |
Current CPC
Class: |
Y10T 442/2893 20150401;
Y10T 442/2041 20150401; Y10T 442/3472 20150401; F41H 5/0485
20130101; Y10T 442/2861 20150401; B32B 5/26 20130101; Y10T 442/643
20150401; B32B 5/28 20130101; Y10T 442/2016 20150401; Y10T 442/2262
20150401; Y10T 442/3707 20150401; Y10T 442/2623 20150401; Y10T
442/2615 20150401; Y10T 442/2902 20150401; B32B 27/04 20130101;
Y10T 442/659 20150401; Y10T 442/2213 20150401 |
Class at
Publication: |
89/36.02 ;
156/148; 89/904; 89/914; 89/915 |
International
Class: |
F41H 5/04 20060101
F41H005/04; B32B 37/18 20060101 B32B037/18 |
Claims
1. A ballistic resistant article comprising, in order: a) a first
panel comprising at least one woven fibrous layer; b) a second
panel comprising a plurality of non-woven fibrous layers, each of
the non-woven fibrous layers being consolidated with the other
non-woven fibrous layers, each of the non-woven fibrous layers
comprising a unidirectional parallel array of fibers, each of said
fibers having a surface, and the surfaces of said fibers being
coated with a polymeric composition that comprises a hydrolytically
stable, polar polymer which is resistant to dissolution by water,
and resistant to dissolution by one or more organic solvents; and
c) a third panel comprising at least one woven fibrous layer.
2. The ballistic resistant article of claim 1 wherein one or more
of said organic solvents is derived from petroleum.
3. The ballistic resistant article of claim 1 wherein the first
panel is in juxtaposition with the second panel and the second
panel is in juxtaposition with the third panel.
4. The ballistic resistant article of claim 1 wherein the first
panel is in immediate juxtaposition with the second panel and the
second panel is in immediate juxtaposition with the third
panel.
5. The ballistic resistant article of claim 1 wherein the first
panel is attached to the second panel and the second panel is
attached to the third panel.
6. (canceled)
7. The ballistic resistant article of claim 1 wherein said
polymeric composition comprises a polar, vinyl-based polymer.
8. The ballistic resistant article of claim 1 wherein said
polymeric composition comprises a diene rubber modified with polar
groups, a styrenic block copolymer modified with polar groups, a
polar vinyl-based polymer, a polar acrylic polymer, a polyvinyl
chloride homopolymer, a polyvinyl chloride copolymer, a polyvinyl
chloride terpolymer, polyvinyl butyral, polyvinylidene chloride,
polyvinylidene fluoride, a polar ethylene vinyl acetate copolymer,
a polar ethylene acrylic acid copolymer, silicone, a thermoplastic
polyurethane, a nitrile rubber, a polychloroprene, a polycarbonate,
a polyketone, a polyamide, a cellulosic, a polyimide, a polyester,
an epoxy, an alkyd, a phenolic, a polyacrylonitrile, a polyether
sulfone or a combination thereof.
9. The ballistic resistant article of claim 1 wherein said
polymeric composition comprises a hydrolytically stable
thermoplastic polyurethane.
10. The ballistic resistant article of claim 1 wherein said first
panel, second panel and third panel each comprise fibers having a
tenacity of about 7 g/denier or more and a tensile modulus of about
150 g/denier or more.
11. The ballistic resistant article of claim 1 wherein said first
panel, second panel and third panel each independently comprise one
or more polyolefin fibers, aramid fibers, polybenzazole fibers,
polyvinyl alcohol fibers, polyamide fibers, polyethylene
terephthalate fibers, polyethylene naphthalate fibers,
polyacrylonitrile fibers, liquid crystal copolyester fibers, glass
fibers, carbon fibers, rigid rod fibers, or a combination
thereof.
12. The ballistic resistant article of claim 1 wherein said first
panel, second panel and third panel each comprise aramid
fibers.
13. The ballistic resistant article of claim 1 wherein said first
panel, second panel and third panel each comprise polyethylene
fibers.
14. The ballistic resistant article of claim 1 wherein said
polymeric composition comprises from about 7% to about 20% by
weight of the second panel.
15. The ballistic resistant article of claim 1 wherein said second
panel comprises a plurality of unidirectional, non-woven fiber
layers that are cross-plied at a 90.degree. angle relative to a
longitudinal fiber direction of each adjacent fiber layer.
16. The ballistic resistant article of claim 1 comprising at least
one additional panel juxtaposed with said third panel, the at least
one additional panel comprising: i) at least one woven fibrous
layer; or ii) a plurality of non-woven fibrous layers, each of the
non-woven fibrous layers being consolidated with the other
non-woven fibrous layers, each of the non-woven fibrous layers
comprising a unidirectional parallel array of fibers, each of said
fibers having a surface, and the surfaces of said fibers being
coated with a polymeric composition that comprises a hydrolytically
stable, polar polymer which is resistant to dissolution by water,
and resistant to dissolution by one or more organic solvents; or
iii) both an additional panel comprising i) and an additional panel
comprising ii).
17. The ballistic resistant article of claim 1 which comprises
flexible armor.
18. The ballistic resistant article of claim 1 wherein the second
panel comprises fibers having 100% of their surface area coated
with said polymeric composition.
19. A ballistic resistant article comprising, in order: a) a first
panel comprising a plurality of non-woven fibrous layers, each of
the non-woven fibrous layers being consolidated with the other
non-woven fibrous layers, each of the non-woven fibrous layers
comprising a unidirectional parallel array of fibers, each of said
fibers having a surface, and the surfaces of said fibers being
coated with a polymeric composition that comprises a hydrolytically
stable, polar polymer which is resistant to dissolution by water,
and resistant to dissolution by one or more organic solvents; b) a
second panel comprising at least one woven fibrous layer; and c) a
third panel comprising a plurality of non-woven fibrous layers,
each of the non-woven fibrous layers being consolidated with the
other non-woven fibrous layers, each of the non-woven fibrous
layers comprising a unidirectional parallel array of fibers, each
of said fibers having a surface, and the surfaces of said fibers
being coated with a polymeric composition that comprises a
hydrolytically stable, polar polymer which is resistant to
dissolution by water, and resistant to dissolution by one or more
organic solvents.
20. The ballistic resistant article of claim 19 wherein one or more
of said organic solvents is derived from petroleum.
21. The ballistic resistant article of claim 19 wherein the first
panel is in juxtaposition with the second panel and the second
panel is in juxtaposition with the third panel.
22. The ballistic resistant article of claim 19 wherein the first
panel is in immediate juxtaposition with the second panel and the
second panel is in immediate juxtaposition with the third
panel.
23. The ballistic resistant article of claim 19 wherein the first
panel is attached to the second panel and the second panel is
attached to the third panel.
24. (canceled)
25. The ballistic resistant article of claim 19 wherein said
polymeric composition comprises a polar, vinyl-based polymer.
26. The ballistic resistant article of claim 1 wherein said
polymeric composition comprises a diene rubber modified with polar
groups, a styrenic block copolymer modified with polar groups, a
polar vinyl-based polymer, a polar acrylic polymer, a polyvinyl
chloride homopolymer, a polyvinyl chloride copolymer, a polyvinyl
chloride terpolymer, polyvinyl butyral, polyvinylidene chloride,
polyvinylidene fluoride, a polar ethylene vinyl acetate copolymer,
a polar ethylene acrylic acid copolymer, silicone, a thermoplastic
polyurethane, a nitrile rubber, a polychloroprene, a polycarbonate,
a polyketone, a polyamide, a cellulosic, a polyimide, a polyester,
an epoxy, an alkyd, a phenolic, a polyacrylonitrile, a polyether
sulfone or a combination thereof.
27. The ballistic resistant article of claim 19 wherein said
polymeric composition comprises a hydrolytically stable,
thermoplastic polyurethane.
28. The ballistic resistant article of claim 19 wherein said first
panel, second panel and third panel each comprise fibers having a
tenacity of about 7 g/denier or more and a tensile modulus of about
150 g/denier or more.
29. The ballistic resistant article of claim 19 wherein said first
panel, second panel and third panel each independently comprise one
or more polyolefin fibers, aramid fibers, polybenzazole fibers,
polyvinyl alcohol fibers, polyamide fibers, polyethylene
terephthalate fibers, polyethylene naphthalate fibers,
polyacrylonitrile fibers, liquid crystal copolyester fibers, glass
fibers, carbon fibers, rigid rod fibers, or a combination
thereof.
30. The ballistic resistant article of claim 19 wherein said first
panel, second panel and third panel each comprise aramid
fibers.
31. The ballistic resistant article of claim 19 wherein said first
panel, second panel and third panel each comprise polyethylene
fibers.
32. The ballistic resistant article of claim 19 wherein said
polymeric composition comprises from about 7% to about 20% by
weight of the each of the first panel and the third panel.
33. The ballistic resistant article of claim 19 wherein said first
panel and said third panel comprise a plurality of unidirectional,
non-woven fiber layers that are cross-plied at a 90.degree. angle
relative to a longitudinal fiber direction of each adjacent fiber
layer.
34. The ballistic resistant article of claim 19 comprising at least
one additional panel adjoining said third panel, the at least one
additional panel comprising: i) at least one woven fibrous layer,
or ii) a plurality of non-woven fibrous layers, each of the
non-woven fibrous layers being consolidated with the other
non-woven fibrous layers, each of the non-woven fibrous layers
comprising a unidirectional parallel array of fibers, each of said
fibers having a surface, and the surfaces of said fibers being
coated with a polymeric composition that comprises a hydrolytically
stable, polar polymer which is resistant to dissolution by water,
and resistant to dissolution by one or more organic solvents; or
iii) both an additional panel comprising i) and an additional panel
comprising ii).
35. The ballistic resistant article of claim 19 which comprises
flexible armor.
36. The ballistic resistant article of claim 19 wherein said first
panel and said second panel comprise fibers having 100% of their
surface area coated with said polymeric composition.
37. A method for forming a ballistic resistant article comprising:
a) forming a first panel comprising at least one woven fibrous
layer; b) forming a second panel comprising a plurality of
non-woven fibrous layers, each of the non-woven fibrous layers
being consolidated with the other non-woven fibrous layers, each of
the non-woven fibrous layers comprising a unidirectional parallel
array of fibers, each of said fibers having a surface, and the
surfaces of said fibers being coated with a polymeric composition
that comprises a hydrolytically stable, polar polymer which is
resistant to dissolution by water, and resistant to dissolution by
one or more organic solvents; c) forming a third panel comprising
at least one woven fibrous layer; and d) juxtaposing said first
panel with said second panel, and juxtaposing said second panel
with said third panel.
38. The method of claim 37 wherein the first panel is attached to
the second panel and the second panel is attached to the third
panel.
39. The method of claim 37 further comprising juxtaposing at least
one additional panel with said third panel, the at least one
additional panel comprising: i) at least one woven fibrous layer;
or ii) a plurality of non-woven fibrous layers, each of the
non-woven fibrous layers being consolidated with the other
non-woven fibrous layers, each of the non-woven fibrous layers
comprising a unidirectional parallel array of fibers, each of said
fibers having a surface, and the surfaces of said fibers being
coated with a polymeric composition that comprises a hydrolytically
stable, polar polymer which is resistant to dissolution by water,
and resistant to dissolution by one or more organic solvents; or
iii) juxtaposing both an additional panel comprising i) and an
additional panel comprising ii) with said third panel.
40. A method for forming a ballistic resistant article comprising:
a) forming a first panel comprising a plurality of non-woven
fibrous layers, each of the non-woven fibrous layers being
consolidated with the other non-woven fibrous layers, each of the
non-woven fibrous layers comprising a unidirectional parallel array
of fibers, each of said fibers having a surface, and the surfaces
of said fibers being coated with a polymeric composition that
comprises a hydrolytically stable, polar polymer which is resistant
to dissolution by water, and resistant to dissolution by one or
more organic solvents; b) forming a second panel comprising at
least one woven fibrous layer; c) forming a third panel comprising
a plurality of non-woven fibrous layers, each of the non-woven
fibrous layers being consolidated with the other non-woven fibrous
layers, each of the non-woven fibrous layers comprising a
unidirectional parallel array of fibers, each of said fibers having
a surface, and the surfaces of said fibers being coated with a
polymeric composition that comprises a hydrolytically stable, polar
polymer which is resistant to dissolution by water, and resistant
to dissolution by one or more organic solvents; and d) juxtaposing
said first panel with said second panel, and juxtaposing said
second panel with said third panel.
41. The method of claim 40 wherein the first panel is attached to
the second panel and the second panel is attached to the third
panel.
42. The method of claim 40 further comprising juxtaposing at least
one additional panel with said third panel, the at least one
additional panel comprising: i) at least one woven fibrous layer;
or ii) a plurality of non-woven fibrous layers, each of the
non-woven fibrous layers being consolidated with the other
non-woven fibrous layers, each of the non-woven fibrous layers
comprising a unidirectional parallel array of fibers, each of said
fibers having a surface, and the surfaces of said fibers being
coated with a polymeric composition that comprises a hydrolytically
stable, polar polymer which is resistant to dissolution by water,
and resistant to dissolution by one or more organic solvents; or
iii) juxtaposing both an additional panel comprising i) and an
additional panel comprising ii) with said third panel.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to ballistic resistant articles
having excellent resistance to deterioration due to liquid
exposure. More particularly, the invention pertains to ballistic
resistant structures and articles formed from a hybrid of woven and
non-woven fibrous components that retain their superior ballistic
resistance performance after exposure to liquids such as sea water
and organic solvents, such as gasoline and other petroleum-based
products.
[0003] 2. Description of the Related Art
[0004] Ballistic resistant articles containing high strength fibers
that have excellent properties against projectiles are well known.
Articles such as bulletproof vests, helmets, vehicle panels and
structural members of military equipment are typically made from
fabrics comprising high strength fibers. High strength fibers
conventionally used include polyethylene fibers, aramid fibers such
as poly(phenylenediamine terephthalamide), graphite fibers, nylon
fibers, glass fibers and the like. For many applications, such as
vests or parts of vests, the fibers may be used in a woven or
knitted fabric. For other applications, the fibers may be
encapsulated or embedded in a matrix material to form non-woven
rigid or flexible fabrics.
[0005] Various ballistic resistant constructions are known that are
useful for the formation of hard or soft armor articles such as
helmets, panels and vests. For example, U.S. Pat. Nos. 4,403,012,
4,457,985, 4,613,535, 4,623,574, 4,650,710, 4,737,402, 4,748,064,
5,552,208, 5,587,230, 6,642,159, 6,841,492, 6,846,758, all of which
are incorporated herein by reference, describe ballistic resistant
composites which include high strength fibers made from materials
such as extended chain ultra-high molecular weight polyethylene.
These composites display varying degrees of resistance to
penetration by high speed impact from projectiles such as bullets,
shells, shrapnel and the like.
[0006] For example, U.S. Pat. Nos. 4,623,574 and 4,748,064 disclose
simple composite structures comprising high strength fibers
embedded in an elastomeric matrix. U.S. Pat. No. 4,650,710
discloses a flexible article of manufacture comprising a plurality
of flexible layers comprised of high strength, extended chain
polyolefin (ECP) fibers. The fibers of the network are coated with
a low modulus elastomeric material. U.S. Pat. Nos. 5,552,208 and
5,587,230 disclose an article and method for making an article
comprising at least one network of high strength fibers and a
matrix composition that includes a vinyl ester and diallyl
phthalate. U.S. Pat. No. 6,642,159 discloses an impact resistant
rigid composite having a plurality of fibrous layers which comprise
a network of filaments disposed in a matrix, with elastomeric
layers there between. The composite is bonded to a hard plate to
increase protection against armor piercing projectiles.
[0007] Hard or rigid body armor provides good ballistic resistance,
but can be very stiff and bulky. Accordingly, body armor garments,
such as ballistic resistant vests, are preferably formed from
flexible or soft armor materials. However, while such flexible or
soft materials exhibit excellent ballistic resistance properties,
they also generally exhibit poor resistance to liquids, including
seawater and organic solvents, such as gasoline and other solvents
derived from petroleum. This is problematic because the ballistic
resistance performance of such materials is generally known to
deteriorate when exposed to or submerged in liquids. Accordingly,
there is a need in the art for soft, flexible ballistic resistant
materials that perform at acceptable standards after being
contacted with or submerged in a variety of liquids, such as
gasoline, gun lube, petroleum and water. The invention provides a
hybrid combination of woven and non-woven ballistic resistant
materials, at least one of which is formed with a matrix material
that is resistant to both water and one or more organic
solvents.
[0008] Hybrid ballistic resistant structures, in and of themselves,
are known. For example, U.S. Pat. Nos. 5,179,244 and 5,180,880
teach soft or hard body armor utilizing a plurality of plies made
from dissimilar ballistic materials, joining aramid and non-aramid
fiber plies into a combined structure and utilizing polymeric
matrix materials that deteriorate when exposed to liquids. U.S.
Pat. No. 5,926,842 also describes hybridized ballistic resistant
structures utilizing polymeric matrix materials that deteriorate
when exposed to liquids. Further, U.S. Pat. No. 6,119,575 teaches a
hybrid structure containing a first section of aromatic fibers, a
second section of a woven plastic and a third section of polyolefin
fibers.
[0009] The present invention provides an improved hybrid structure
that incorporates the benefits of dissimilar materials and offers
the desired protection from liquids. Particularly, the invention
provides hybrid ballistic resistant structures incorporating at
least one layer which is preferably formed with a hydrolytically
stable, polar matrix material. Polar polymers are generally
resistant to dissolution by non-polar organic solvents, and
hydrolytically stable polymers are generally resistant to
degradation due to sea water exposure. It has been discovered that
matrix polymers having both properties advantageously contribute to
the retention of the ballistic resistance properties of a fabric
after prolonged exposure to potentially harmful liquids.
SUMMARY OF THE INVENTION
[0010] The invention provides a ballistic resistant article
comprising, in order:
a) a first panel comprising at least one woven fibrous layer; b) a
second panel comprising a plurality of non-woven fibrous layers,
each of the non-woven fibrous layers being consolidated with the
other non-woven fibrous layers, each of the non-woven fibrous
layers comprising a unidirectional parallel array of fibers, each
of said fibers having a surface, and the surfaces of said fibers
being coated with a polymeric composition that is resistant to
dissolution by water, and resistant to dissolution by one or more
organic solvents; and c) a third panel comprising at least one
woven fibrous layer.
[0011] The invention also provides a ballistic resistant article
comprising, in order:
a) a first panel comprising a plurality of non-woven fibrous
layers, each of the non-woven fibrous layers being consolidated
with the other non-woven fibrous layers, each of the non-woven
fibrous layers comprising a unidirectional parallel array of
fibers, each of said fibers having a surface, and the surfaces of
said fibers being coated with a polymeric composition that is
resistant to dissolution by water, and resistant to dissolution by
one or more organic solvents; b) a second panel comprising at least
one woven fibrous layer; and c) a third panel comprising a
plurality of non-woven fibrous layers, each of the non-woven
fibrous layers being consolidated with the other non-woven fibrous
layers, each of the non-woven fibrous layers comprising a
unidirectional parallel array of fibers, each of said fibers having
a surface, and the surfaces of said fibers being coated with a
polymeric composition that is resistant to dissolution by water,
and resistant to dissolution by one or more organic solvents.
[0012] The invention further provides a method for forming a
ballistic resistant article comprising:
a) forming a first panel comprising at least one woven fibrous
layer; b) forming a second panel comprising a plurality of
non-woven fibrous layers, each of the non-woven fibrous layers
being consolidated with the other non-woven fibrous layers, each of
the non-woven fibrous layers comprising a unidirectional parallel
array of fibers, each of said fibers having a surface, and the
surfaces of said fibers being coated with a polymeric composition
that is resistant to dissolution by water, and resistant to
dissolution by one or more organic solvents; c) forming a third
panel comprising at least one woven fibrous layer; and d)
juxtaposing said first panel with said second panel, and
juxtaposing said second panel with said third panel.
[0013] The invention also provides a method for forming a ballistic
resistant article comprising:
a) forming a first panel comprising a plurality of non-woven
fibrous layers, each of the non-woven fibrous layers being
consolidated with the other non-woven fibrous layers, each of the
non-woven fibrous layers comprising a unidirectional parallel array
of fibers, each of said fibers having a surface, and the surfaces
of said fibers being coated with a polymeric composition that is
resistant to dissolution by water, and resistant to dissolution by
one or more organic solvents; b) forming a second panel comprising
at least one woven fibrous layer; c) forming a third panel
comprising a plurality of non-woven fibrous layers, each of the
non-woven fibrous layers being consolidated with the other
non-woven fibrous layers, each of the non-woven fibrous layers
comprising a unidirectional parallel array of fibers, each of said
fibers having a surface, and the surfaces of said fibers being
coated with a polymeric composition that is resistant to
dissolution by water, and resistant to dissolution by one or more
organic solvents; and d) juxtaposing said first panel with said
second panel, and juxtaposing said second panel with said third
panel.
DETAILED DESCRIPTION OF THE INVENTION
[0014] The invention presents articles that retain superior
ballistic penetration resistance after exposure to water,
particularly sea water, and organic solvents, particularly solvents
derived from petroleum such as gasoline. For the purposes of the
invention, articles that have superior ballistic penetration
resistance describe those which exhibit excellent properties
against deformable projectiles. The articles also exhibit excellent
resistance properties against fragment penetration, such as
shrapnel.
[0015] The articles include three or more individual panels, each
panel comprising at least one layer of a woven fibrous material or
a non-woven fibrous material. In a first embodiment, a panel
comprising a plurality of non-woven fibrous layers is positioned
between two opposing panels, each comprising at least one woven
fibrous layer. In a second embodiment, a panel comprising at least
one woven fibrous layer is positioned between two opposing panels,
each comprising a plurality of non-woven fibrous layers. In each
embodiment, a panel of non-woven fibrous material comprises at
least one single-layer, consolidated network of fibers in an
elastomeric or rigid polymer composition, which polymer composition
is referred to in the art as a matrix composition. More
particularly, a single-layer, consolidated network of fibers
comprises a plurality of fiber layers stacked together, each fiber
layer comprising a plurality of fibers coated with the matrix
composition and unidirectionally aligned in an array so that they
are substantially parallel to each other along a common fiber
direction. The stacked fiber layers are consolidated to form the
single-layer, consolidated network, uniting the fibers and the
matrix composition of each component fiber layer. The consolidated
network may also comprise a plurality of yarns that are coated with
such a matrix composition, formed into a plurality of layers and
consolidated into a fabric.
[0016] In each of the first and second embodiments, the first panel
is in juxtaposition with the second panel and the second panel is
in juxtaposition with the third panel. More particularly, the first
panel is in immediate juxtaposition with the second panel and the
second panel is in immediate juxtaposition with the third panel.
Additionally, the first panel may be attached to the second panel
and the second panel may be attached to the third panel, or the
panels may simply be positioned face-to-face in a non-attached
array.
[0017] Alternately, the articles of the invention may further
comprise one or more additional panels, each panel comprising at
least one woven fibrous layer or comprising a plurality of
non-woven fibrous layers, each of the non-woven fibrous layers
being consolidated with the other non-woven fibrous layers, each of
the non-woven fibrous layers comprising a unidirectional parallel
array of fibers, each of said fibers having a surface, and the
surfaces of said fibers being coated with a polymeric composition
that is resistant to dissolution by water, and resistant to
dissolution by one or more organic solvents. In a preferred
embodiment of the invention, the articles of the invention comprise
more than three individual panels, wherein each panel of a woven
fibrous material is immediately juxtaposed with a panel of a
non-woven fibrous material, such that the woven and non-woven
panels alternate. Further, as previously stated, a single panel of
woven fibrous material may comprise more than one woven fibrous
layer. Also, a single panel of non-woven fibrous layers may include
more than one single-layer, consolidated network of non-woven
fibers. For example, a preferred structure of the invention
comprises a first panel which comprises ten layers of a woven
fibrous material, a second panel comprising ten separate
single-layer, consolidated fiber networks (each single-layer,
consolidated fiber network formed from two united, unidirectional
fiber layers), and a third panel comprising ten layers of a woven
fibrous material.
[0018] The number of layers forming a single panel, and the number
of layers forming the non-woven composite vary depending upon the
ultimate use of the desired ballistic resistant article. For
example, in body armor vests for military applications, in order to
form an article composite that achieves a desired 1.0 pound per
square foot areal density (4.9 kg/m.sup.2), a total of at 22
individual plies may be required, wherein the plies may be woven,
knitted, felted or non-woven fabrics formed from the high-strength
fibers described herein, and the layers may or may not be attached
together. In another embodiment, body armor vests for law
enforcement use may have a number of layers based on the National
Institute of Justice (NIJ) Threat Level. For example, for an NIJ
Threat Level IIIA vest, there may also be a total of 22 layers. For
a lower NIJ Threat Level, fewer layers may be employed.
[0019] In each embodiment wherein a single panel includes a
plurality of woven fibrous layers or a plurality of single-layer,
consolidated fiber networks, the multiple layers may be adjoined in
a bonded array or may juxtaposed in a non-bonded array. Methods of
bonding are well known in the art, and include stitching, quilting,
bolting, adhering with adhesive materials, and the like.
Preferably, said plurality of layers are attached by stitching
together at edge areas of the layers. Further, each individual
panel may be adjoined in a bonded array using the same techniques,
or may juxtaposed in a non-bonded array.
[0020] For the purposes of the present invention, a "fiber" is an
elongate body the length dimension of which is much greater than
the transverse dimensions of width and thickness. The
cross-sections of fibers for use in this invention may vary widely.
They may be circular, flat or oblong in cross-section. Accordingly,
the term fiber includes filaments, ribbons, strips and the like
having regular or irregular cross-section. They may also be of
irregular or regular multi-lobal cross-section having one or more
regular or irregular lobes projecting from the linear or
longitudinal axis of the fibers. It is preferred that the fibers
are single lobed and have a substantially circular
cross-section.
[0021] As used herein, a "yarn" is a strand of interlocked fibers.
An "array" describes an orderly arrangement of fibers or yarns, and
a "parallel array" describes an orderly parallel arrangement of
fibers or yarns. A fiber "layer" describes a planar arrangement of
woven or non-woven fibers or yarns. A fiber "network" denotes a
plurality of interconnected fiber or yarn layers. A "consolidated
network" describes a consolidated combination of fiber layers with
a matrix composition. As used herein, a "single layer" structure
refers to structure composed of one or more individual fiber layers
that have been consolidated into a single unitary structure. In
general, a "fabric" may relate to either a woven or non-woven
material.
[0022] In accordance with the invention, each of the fibers present
in each non-woven fibrous layer has one or more surfaces, and the
surfaces of the fibers are coated with a polymeric matrix
composition that is resistant to dissolution by water, and
resistant to dissolution by one or more organic solvents. More
specifically, the outer surface of each fiber is substantially
coated with said water and organic solvent resistant polymeric
matrix composition such that preferably 100% of the surface area of
each individual fiber is covered by said polymeric matrix
composition. If the non-woven fibrous layers comprise a plurality
of yarns, each fiber forming a single strand of yarn is coated with
the polymeric matrix composition.
[0023] For the purposes of the present invention, the term "coated"
is not intended to limit the method by which the polymeric matrix
composition is applied onto the fiber surface or surfaces. The
application of the matrix is conducted prior to consolidating the
fiber layers, and any appropriate method of applying the polymeric
matrix composition onto the fiber surfaces may be utilized.
Accordingly, the fibers of the invention are coated on, impregnated
with, embedded in, or otherwise applied with a matrix composition
by applying the matrix composition to the fibers and then
consolidating the matrix composition-fibers combination to form a
composite. By "consolidating" is meant that the matrix material and
each individual fiber layer are combined into a single unitary
layer. Consolidation can occur via drying, cooling, heating,
pressure or a combination thereof. The term "composite" refers to
consolidated combinations of fibers with the matrix material. The
term "matrix" as used herein is well known in the art, and is used
to represent a binder material, such as a polymeric binder
material, that binds the fibers together after consolidation.
[0024] With regard to the woven fibrous layers, it is generally not
necessary for the fibers to be coated with the polymeric matrix
composition, because no consolidation is conducted. However, it is
within the scope of the invention that the fibers comprising the
woven fibrous layers may be coated with a polymeric matrix
composition, preferably with a polymeric composition that is
resistant to dissolution by water, and resistant to dissolution by
one or more organic solvents.
[0025] As described herein, the polymeric matrix composition is
independently resistant to dissolution by, particularly sea water,
and independently resistant to dissolution by one or more organic
solvents, such as diesel or non-diesel gasoline, gun lube,
petroleum and organic solvents derived from petroleum. The
polymeric matrix composition is also preferably resistant to
dissolution by a combination of water and one or more organic
solvents. Conventionally, there are two types of polymers which are
predominantly used in the manufacture of soft body armor, i.e.
solvent-based and water-based synthetic rubbers; and polyurethane
(typically water-based). Such synthetic rubbers are generally block
copolymers of styrene and isoprene, particularly
styrene-isoprene-styrene (SIS) copolymers. These SIS copolymers are
processed in both solvent-based solutions and water-based
dispersions. Solvent-based synthetic rubbers are generally
sensitive to petroleum solvents and will dissolve upon exposure.
Such solvent-based synthetic rubbers are generally unaffected by
water. However, water-based dispersions can be very sensitive to
water and sea water, depending on the method and materials of
dispersion. Currently employed polyurethane matrix polymers, due to
their inherent polarity, are generally resistant to petroleum
solvents, with some exceptions. Water-based polyurethanes can be
degraded by water, particularly sea water, which can cause a
hydrolytic breakdown of the polyurethane chain, resulting in a
reduction in both molecular weight and physical properties.
[0026] It has been unexpectedly found that polymers which are both
polar and hydrolytically stable achieve the desired balance of
water resistance and organic solvent resistance, while maintaining
the desired ballistic resistance properties necessary for an
effective ballistic resistant article. Polar polymers are generally
resistant to dissolution by non-polar organic solvents, and
hydrolytically stable polymers are stable to hydrolysis by water,
i.e. resistant to chemical decomposition when exposed to water.
Accordingly, ballistic resistant articles formed incorporating such
polymeric matrix materials retain their ballistic resistance
properties after prolonged exposure to such liquids.
[0027] In the preferred embodiments of the invention, suitable
polymeric matrix compositions preferably include synthetic rubbers,
diene rubbers and styrenic block copolymers including
styrene-isoprene-styrene (SIS) and styrene-butadiene-styrene (SBS),
polar vinyl-based polymers, polar acrylic polymers, polyvinyl
chloride homopolymer, polyvinyl chloride copolymer, polyvinyl
chloride terpolymer, polyvinyl butyral, polyvinylidene chloride,
polyvinylidene fluoride polar ethylene vinyl acetate copolymers,
polar ethylene acrylic acid copolymers, silicone, thermoplastic
polyurethanes, nitrile rubber, polychloroprenes such as Neoprene
(manufactured by DuPont), polycarbonates, polyketones, polyamides,
cellulosics, polyimides, polyesters, epoxies, alkyds, phenolics,
polyacrylonitrile, polyether sulfones and combinations thereof.
[0028] Also suitable are other polar, hydrolytically stable
polymers not specified herein. Non-polar synthetic rubbers and
styrenic block copolymers, such as SIS and SBS, generally should be
modified with polar groups, such as by the grafting of carboxyl
groups or adding acid or alcohol functionality, or any other polar
group, to be sufficiently oil repellant. For example, non-polar
polymers may be copolymerized with monomers containing carboxylic
acid groups such as acrylic acid or maleic acid, or another polar
group such as amino, nitro or sulfonate groups. Such techniques are
well known in the art.
[0029] Particularly preferred are polar polymers which have a C-C
polymer backbone. As stated herein, polar polymers are generally
resistant to dissolution by non-polar organic solvents. Polymers
having a C--C-backbone, such as vinyl-based polymers including, for
example, acrylics, ethylene vinyl acetate, polyvinylidene chloride,
etc., have a hydrolytically stable molecular structure. Also
particularly preferred are polar, thermoplastic polyurethanes,
particularly those that have been formulated to enhance hydrolytic
stability. Unlike C-C linkages, urethane linkages and ester
linkages are generally susceptible hydrolytic degradation.
Accordingly, polymers having such linkages generally are formulated
or modified to enhance water repellency and hydrolytic stability.
For example, polyurethanes may be formulated to enhance hydrolytic
stability through copolymerization with polyether polyol or
aliphatic polyol components, or other components known to enhance
hydrolytic stability. The main polyurethane producing reaction is
between an aliphatic or aromatic diisocyanate and a polyol,
typically a polyethylene glycol or polyester polyol, in the
presence of catalysts. Selection of the isocyanate co-reactant can
also influence the hydrolytic stability. Bulky pendant groups on
either or both of the co-reactants can also protect the urethane
linkage from attack. Polyurethane can be made in a variety of
densities and hardnesses by varying the type of monomers used and
by adding other substances to modify their characteristics or
enhance their hydrolytic stability, such as with water repellants,
pH buffers, cross-linking agents and chelating agents, etc. The
most preferred polyurethane matrix composition comprises a polar,
hydrolytically stable, polyether- or aliphatic-based thermoplastic
polyurethane, which are preferred over polyester-based
polyurethanes.
[0030] The thermoplastic polyurethane may be a homopolymer, a
copolymer, or a blend of a polyurethane homopolymer and a
polyurethane copolymer. Such polymers are commercially available.
Such polyurethanes are generally available as aqueous solutions,
dispersions or emulsions, in which the solids component may range
from about 20% to 80% by weight, more preferably from about 40% to
about 60% by weight, with the remaining weight being water. An
aqueous system is preferred for ease of use. Preferred polyurethane
coated fibrous layers are described in U.S. patent application Ser.
No. 11/213,253, which is incorporated herein by reference in its
entirety.
[0031] Useful polymeric matrix compositions include both low
modulus, thermoplastic matrix materials and high modulus,
thermosetting matrix materials having the above desired properties,
or a combination thereof. Suitable thermoplastic matrix
compositions preferably have an initial tensile modulus of less
than about 6,000 psi (41.3 MPa), and suitable high modulus,
thermosetting compositions preferably have an initial tensile
modulus of at least about 300,000 psi (2068 MPa), each as measured
at 37.degree. C. by ASTM D638. As used herein throughout, the term
tensile modulus means the modulus of elasticity as measured by ASTM
D638 for a matrix material. For the manufacture of soft body armor,
low modulus thermoplastic matrix compositions are most preferred.
Preferred low modulus thermoplastic compositions have a tensile
modulus of about 4,000 psi (27.6 MPa) or less, more preferably
about 2400 psi (16.5 MPa) or less, more preferably 1200 psi (8.23
MPa) or less, and most preferably is about 500 psi (3.45 MPa) or
less. The glass transition temperature (Tg) of the preferred
thermoplastic matrix composition is preferably less than about
0.degree. C., more preferably the less than about -40.degree. C.,
and most preferably less than about -50.degree. C. Preferred
thermoplastic compositions also have a preferred elongation to
break of at least about 50%, more preferably at least about 100%
and most preferably an elongation to break of at least about
300%.
[0032] The rigidity, impact and ballistic properties of the
articles formed from the fabric composites of the invention are
effected by the tensile modulus of the matrix polymer. For example,
U.S. Pat. No. 4,623,574 discloses that fiber reinforced composites
constructed with elastomeric matrices having tensile moduli less
than about 6000 psi (41,300 kPa) have superior ballistic properties
compared both to composites constructed with higher modulus
polymers, and also compared to the same fiber structure without a
matrix. However, low tensile modulus matrix polymers also yield
lower rigidity composites. Further, in certain applications,
particularly those where a composite must function in both
anti-ballistic and structural modes, there is needed a superior
combination of ballistic resistance and rigidity. Accordingly, the
most appropriate type of matrix polymer to be used will vary
depending on the type of article to be formed from the fabrics of
the invention. In order to achieve a compromise in both properties,
a suitable matrix composition may combine both low modulus and high
modulus materials to form a single matrix composition, so long as
the combination produces a polymeric matrix composition that is
resistant to dissolution by water and resistant to dissolution by
one or more organic solvents.
[0033] In the preferred embodiment of the invention, the proportion
of the matrix composition making up each non-woven composite panel
preferably comprises from about 5% to about 30% by weight of the
composite, more preferably from about 7% to about 20% by weight of
the composite, more preferably from about 7% to about 16% and most
preferably from about 11% to about 15% by weight of the composite.
The matrix composition may also include fillers such as carbon
black or silica, may be extended with oils, or may be vulcanized by
sulfur, peroxide, metal oxide or radiation cure systems as is well
known in the art.
[0034] The remaining portion of the composite is preferably
composed of fibers. In accordance with the invention, the fibers
comprising each of the woven and non-woven fibrous layers
preferably comprise high-strength, high tensile modulus fibers. As
used herein, a "high-strength, high tensile modulus fiber" is one
which has a preferred tenacity of at least about 7 g/denier or
more, a preferred tensile modulus of at least about 150 g/denier or
more, and preferably an energy-to-break of at least about 8 J/g or
more, each both as measured by ASTM D2256. As used herein, the term
"denier" refers to the unit of linear density, equal to the mass in
grams per 9000 meters of fiber or yarn. As used herein, the term
"tenacity" refers to the tensile stress expressed as force (grams)
per unit linear density (denier) of an unstressed specimen. The
"initial modulus" of a fiber is the property of a material
representative of its resistance to deformation. The term "tensile
modulus" refers to the ratio of the change in tenacity, expressed
in grams-force per denier (g/d) to the change in strain, expressed
as a fraction of the original fiber length (in/in).
[0035] Particularly suitable high-strength, high tensile modulus
fiber materials include extended chain polyolefin fibers, such as
highly oriented, high molecular weight polyethylene fibers,
particularly ultra-high molecular weight polyethylene fibers, and
ultra-high molecular weight polypropylene fibers. Also suitable are
aramid fibers, particularly para-aramid fibers, extended chain
polyvinyl alcohol fibers, extended chain polyacrylonitrile fibers,
polybenzazole fibers, such as polybenzoxazole (PBO) and
polybenzothiazole (PBT) fibers, and liquid crystal copolyester
fibers. Each of these fiber types is conventionally known in the
art.
[0036] In the case of polyethylene, preferred fibers are extended
chain polyethylenes having molecular weights of at least 500,000,
preferably at least one million and more preferably between two
million and five million. Such extended chain polyethylene (ECPE)
fibers may be grown in solution spinning processes such as
described in U.S. Pat. No. 4,137,394 or 4,356,138, which are
incorporated herein by reference, or may be spun from a solution to
form a gel structure, such as described in U.S. Pat. Nos. 4,551,296
and 5,006,390, which are also incorporated herein by reference. A
particularly preferred fiber type for use in the invention are
polyethylene fibers sold under the trademark Spectra.RTM. from
Honeywell International Inc. Spectra.RTM. fibers are well known in
the art and are described, for example, in U.S. Pat. Nos. 4,623,547
and 4,748,064.
[0037] Also particularly preferred are aramid (aromatic polyamide)
or para-aramid fibers. Such are commercially available and are
described, for example, in U.S. Pat. No. 3,671,542. For example,
useful poly(p-phenylene terephthalamide) filaments are produced
commercially by Dupont corporation under the trade name of
KEVLAR.RTM.. Also useful in the practice of this invention are
poly(m-phenylene isophthalamide) fibers produced commercially by
Dupont under the trade name NOMEX.RTM. and fibers produced
commercially by Teij in under the trade name TWARON.RTM..
[0038] Suitable polybenzazole fibers for the practice of this
invention are commercially available and are disclosed for example
in U.S. Pat. Nos. 5,286,833, 5,296,185, 5,356,584, 5,534,205 and
6,040,050, each of which are incorporated herein by reference.
Preferred polybenzazole fibers are ZYLON.RTM. brand fibers from
Toyobo Co. Suitable liquid crystal copolyester fibers for the
practice of this invention are commercially available and are
disclosed, for example, in U.S. Pat. Nos. 3,975,487; 4,118,372 and
4,161,470, each of which is incorporated herein by reference.
[0039] Suitable polypropylene fibers include highly oriented
extended chain polypropylene (ECPP) fibers as described in U.S.
Pat. No. 4,413,110, which is incorporated herein by reference.
Suitable polyvinyl alcohol (PV-OH) fibers are described, for
example, in U.S. Pat. Nos. 4,440,711 and 4,599,267 which are
incorporated herein by reference. Suitable polyacrylonitrile (PAN)
fibers are disclosed, for example, in U.S. Pat. No. 4,535,027,
which is incorporated herein by reference. Each of these fiber
types is conventionally known and are widely commercially
available.
[0040] The other suitable fiber types for use in the present
invention include glass fibers, fibers formed from carbon, fibers
formed from basalt or other minerals, rigid rod fibers such as
M5.RTM. fibers, and combinations of all the above materials, all of
which are commercially available. For example, the fibrous layers
may be formed from a combination of Spectra.RTM. fibers and
Kevlar.RTM. fibers. M50 fibers are manufactured by Magellan Systems
International of Richmond, Va. and are described, for example, in
U.S. Pat. Nos. 5,674,969, 5,939,553, 5,945,537, and 6,040,478, each
of which is incorporated herein by reference. Specifically
preferred fibers include M5.RTM. fibers, polyethylene Spectra.RTM.
fibers, and aramid Kevlar.RTM. fibers. The fibers may be of any
suitable denier, such as, for example, 50 to about 3000 denier,
more preferably from about 200 to 3000 denier, still more
preferably from about 650 to about 1500 denier, and most preferably
from about 800 to about 1300 denier.
[0041] The most preferred fibers for the purposes of the invention
are either high-strength, high tensile modulus extended chain
polyethylene fibers or high-strength, high tensile modulus
para-aramid fibers. As stated above, a high-strength, high tensile
modulus fiber is one which has a preferred tenacity of about 7
g/denier or more, a preferred tensile modulus of about 150 g/denier
or more and a preferred energy-to-break of about 8 J/g or more,
each as measured by ASTM D2256. In the preferred embodiment of the
invention, the tenacity of the fibers should be about 15 g/denier
or more, preferably about 20 g/denier or more, more preferably
about 25 g/denier or more and most preferably about 30 g/denier or
more. The fibers of the invention also have a preferred tensile
modulus of about 300 g/denier or more, more preferably about 400
g/denier or more, more preferably about 500 g/denier or more, more
preferably about 1,000 g/denier or more and most preferably about
1,500 g/denier or more. The fibers of the invention also have a
preferred energy-to-break of about 15 J/g or more, more preferably
about 25 J/g or more, more preferably about 30 J/g or more and most
preferably have an energy-to-break of about 40 J/g or more.
[0042] These combined high strength properties are obtainable by
employing well known processes. U.S. Pat. Nos. 4,413,110,
4,440,711, 4,535,027, 4,457,985, 4,623,547, 4,650,710 and 4,748,064
generally discuss the formation of preferred high strength,
extended chain polyethylene fibers employed in the present
invention. Such methods, including solution grown or gel fiber
processes, are well known in the art. Methods of forming each of
the other preferred fiber types, including para-aramid fibers, are
also conventionally known in the art, and the fibers are
commercially available.
[0043] As discussed above, the matrix may be applied to a fiber in
a variety of ways, and the term "coated" is not intended to limit
the method by which the matrix composition is applied onto the
fiber surface or surfaces. For example, the polymeric matrix
composition may be applied in solution form by spraying or roll
coating a solution of the matrix composition onto fiber surfaces,
wherein a portion of the solution comprises the desired polymer or
polymers and a portion of the solution comprises a solvent capable
of dissolving the polymer or polymers, followed by drying. Another
method is to apply a neat polymer of the coating material to fibers
either as a liquid, a sticky solid or particles in suspension or as
a fluidized bed. Alternatively, the coating may be applied as a
solution or emulsion in a suitable solvent which does not adversely
affect the properties of the fiber at the temperature of
application. For example, the fiber can be transported through a
solution of the matrix composition to substantially coat the fiber
and then dried to form a coated fiber. The resulting coated fiber
can then be arranged into the desired network configuration. In
another coating technique, a layer of fibers may first be arranged,
followed by dipping the layer into a bath of a solution containing
the matrix composition dissolved in a suitable solvent, such that
each individual fiber is substantially coated with the matrix
composition, and then dried through evaporation of the solvent. The
dipping procedure may be repeated several times as required to
place a desired amount of matrix composition coating on the fibers,
preferably encapsulating each of the individual fibers or covering
100% of the fiber surface area with the matrix composition.
[0044] While any liquid capable of dissolving or dispersing a
polymer may be used, preferred groups of solvents include water,
paraffin oils and aromatic solvents or hydrocarbon solvents, with
illustrative specific solvents including paraffin oil, xylene,
toluene, octane, cyclohexane, methyl ethyl ketone (MEK) and
acetone. The techniques used to dissolve or disperse the coating
polymers in the solvents will be those conventionally used for the
coating of similar materials on a variety of substrates.
[0045] Other techniques for applying the coating to the fibers may
be used, including coating of the high modulus precursor (gel
fiber) before the fibers are subjected to a high temperature
stretching operation, either before or after removal of the solvent
from the fiber (if using the gel-spinning fiber forming technique).
The fiber may then be stretched at elevated temperatures to produce
the coated fibers. The gel fiber may be passed through a solution
of the appropriate coating polymer under conditions to attain the
desired coating. Crystallization of the high molecular weight
polymer in the gel fiber may or may not have taken place before the
fiber passes into the solution. Alternatively, the fiber may be
extruded into a fluidized bed of an appropriate polymeric powder.
Furthermore, if a stretching operation or other manipulative
process, e.g. solvent exchanging, drying or the like is conducted,
the coating may be applied to a precursor material of the final
fiber. In the most preferred embodiment of the invention, the
fibers of the invention are first coated with the matrix
composition, followed by arranging a plurality of fibers into
either a woven or non-woven fiber layer. Such techniques are well
known in the art.
[0046] Following the application of the matrix material, the
individual fibers in a non-woven layer may or may not be bonded to
each other prior to consolidation. In the panels of the invention
which comprise non-woven fibrous layers, each non-woven layer
comprises fibers unidirectionally aligned in parallel to one
another along a common fiber direction. As is conventionally known
in the art, excellent ballistic resistance is achieved when
individual fiber layer are cross-plied such that the fiber
alignment direction of one layer is rotated at an angle with
respect to the fiber alignment direction of another layer.
Accordingly, successive layers of such unidirectionally aligned
fibers are preferably rotated with respect to a previous layer. An
example is a two layer structure wherein adjacent layers are
aligned in a 0.degree./90.degree. orientation. However, adjacent
layers can be aligned at virtually any angle between about
0.degree. and about 90.degree. with respect to the longitudinal
fiber direction of another layer. For example, a five layer
non-woven structure may have plies at a
0.degree./45.degree./90.degree./45.degree./0.degree. orientation or
at other angles. In the preferred embodiment of the invention, only
two individual non-woven layers, cross plied at 0.degree. and
90.degree., are consolidated into a single layer network, wherein
one or more of said single layer networks make up a single
non-woven panel. However, it should be understood that the
single-layer consolidated networks of the invention may generally
include any number of cross-plied layers, such as about 20 to about
40 or more layers as may be desired for various applications. Such
rotated unidirectional alignments are described, for example, in
U.S. Pat. Nos. 4,457,985; 4,748,064; 4,916,000; 4,403,012;
4,623,573; and 4,737,402. The non-woven fiber networks can be
constructed using well known methods, such as by the methods
described in U.S. Pat. No. 6,642,159. The non-woven fiber networks
may also comprise a felted structure which is formed using
conventionally known techniques, comprising fibers in a random
orientation embedded in a suitable matrix composition.
[0047] The woven fibrous layers of the invention are also formed
using techniques that are well known in the art using any fabric
weave, such as plain weave, crowfoot weave, basket weave, satin
weave, twill weave and the like. Plain weave is most common. Prior
to weaving, the individual fibers of each woven fibrous material
may or man not be coated with a polymeric matrix composition in a
similar fashion as the non-woven fibrous layers using the same
matrix compositions as the non-woven fibrous layers. However, if
the individual woven fibers are not coated in a matrix composition,
it is preferred that at least one outer surface of each woven layer
be coated or applied with a water repellent coating for additional
protection. Suitable water repellent coatings non-exclusively
include commonly known hydrolytically stable materials, and may
comprise the above described polymeric matrix compositions.
[0048] Suitable bonding conditions for consolidating the fiber
layers into a single layer, consolidated network, or fabric
composite, include conventionally known lamination techniques. A
typical lamination process includes pressing the cross-plied fiber
layers together at about 110.degree. C., under about 200 psi (1379
kPa) pressure for about 30 minutes. The consolidation of the fibers
layers of the invention is preferably conducted at a temperature
from about 200.degree. F. (.about.93.degree. C.) to about
350.degree. F. (.about.177.degree. C.), more preferably at a
temperature from about 200.degree. F. to about 300.degree. F.
(.about.149.degree. C.) and most preferably at a temperature from
about 200.degree. F. to about 280.degree. F. (.about.121.degree.
C.), and at a pressure from about 25 psi (.about.172 kPa) to about
500 psi (3447 kPa) or higher. The consolidation may be conducted in
an autoclave, as is conventionally known in the art. When heating,
it is possible that the matrix can be caused to stick or flow
without completely melting. However, generally, if the matrix
material is caused to melt, relatively little pressure is required
to form the composite, while if the matrix material is only heated
to a sticking point, more pressure is typically required. The
consolidation step may generally take from about 10 seconds to
about 24 hours. However, the temperatures, pressures and times are
generally dependent on the type of polymer, polymer content,
process and type of fiber.
[0049] The thickness of the individual fabric layers and panels
will correspond to the thickness of the individual fibers.
Accordingly, a preferred woven fibrous layer will have a preferred
thickness of from about 25 .mu.m to about 500 .mu.m, more
preferably from about 75 .mu.m to about 385 .mu.m and most
preferably from about 125 .mu.m to about 255 .mu.m. A preferred
single-layer, consolidated network will have a preferred thickness
of from about 12 .mu.m to about 500 .mu.m, more preferably from
about 75 .mu.m to about 385 .mu.m and most preferably from about
125 .mu.m to about 255 .mu.m. The combined hybrid article has a
preferred total thickness of about 63 .mu.m to about 1000 .mu.m,
more preferably from about 125 .mu.m to about 850 .mu.m and most
preferably from about 250 .mu.m to about 725 .mu.m.
[0050] While such thicknesses are preferred, it is to be understood
that other film thicknesses may be produced to satisfy a particular
need and yet fall within the scope of the present invention.
[0051] The multi-panel structures of the invention may be used in
various applications to form a variety of different ballistic
resistant articles using well known techniques. For example,
suitable techniques for forming ballistic resistant articles are
described in, for example, U.S. Pat. Nos. 4,623,574, 4,650,710,
4,748,064, 5,552,208, 5,587,230, 6,642,159, 6,841,492 and
6,846,758.
[0052] The multi-panel structures are particularly useful for the
formation of flexible, soft armor articles, including garments such
as vests, pants, hats, or other articles of clothing, and covers or
blankets, used by military personnel to defeat a number of
ballistic threats, such as 9 mm full metal jacket (FMJ) bullets and
a variety of fragments generated due to explosion of hand-grenades,
artillery shells, Improvised Explosive Devices (IED) and other such
devises encountered in a military and peace keeping missions. As
used herein, "soft" or "flexible" armor is armor that does not
retain its shape when subjected to a significant amount of stress
and is incapable of being free-standing without collapsing. The
multi-panel structures are also useful for the formation of rigid,
hard armor articles. By "hard" armor is meant an article, such as
helmets, panels for military vehicles, or protective shields, which
have sufficient mechanical strength so that it maintains structural
rigidity when subjected to a significant amount of stress and is
capable of being freestanding without collapsing. The structures
can be cut into a plurality of discrete sheets and stacked for
formation into an article or they can be formed into a precursor
which is subsequently used to form an article. Such techniques are
well known in the art.
[0053] Garments of the invention may be formed through methods
conventionally known in the art. Preferably, a garment may be
formed by adjoining the ballistic resistant articles of the
invention with an article of clothing. For example, a vest may
comprise a generic fabric vest that is adjoined with the ballistic
resistant structures of the invention, whereby the inventive
structures are inserted into strategically placed pockets. This
allows for the maximization of ballistic protection, while
minimizing the weight of the vest. As used herein, the terms
"adjoining" or "adjoined" are intended to include attaching, such
as by sewing or adhering and the like, as well as un-attached
coupling or juxtaposition with another fabric, such that the
ballistic resistant articles may optionally be easily removable
from the vest or other article of clothing. Articles used in
forming flexible structures like flexible sheets, vests and other
garments are preferably formed from using a low tensile modulus
matrix composition. Hard articles like helmets and armor are
preferably formed using a high tensile modulus matrix
composition.
[0054] The ballistic resistance properties are determined using
standard testing procedures that are well known in the art.
Particularly, the protective power or penetration resistance of a
structure is normally expressed by citing the impacting velocity at
which 50% of the projectiles penetrate the composite while 50% are
stopped by the shield, also known as the V.sub.50 value. As used
herein, the "penetration resistance" of an article is the
resistance to penetration by a designated threat, such as physical
objects including bullets, fragments, shrapnel and the like, and
non-physical objects, such as a blast from explosion. For
composites of equal areal density, which is the weight of the
composite panel divided by the surface area, the higher the
V.sub.50, the better the resistance of the composite. The ballistic
resistant properties of the articles of the invention will vary
depending on many factors, particularly the type of fibers used to
manufacture the fabrics. However, it has been found that the use of
a polymeric matrix composition that is resistant to dissolution by
water, and resistant to dissolution by one or more organic solvents
does not negatively affect the ballistic properties of the articles
of the invention.
[0055] Flexible ballistic armor formed herein preferably have a
V.sub.50 of at least about 1920 feet/second (fps) (585.6 msec) when
impacted with a 16 grain projectile, after the armor has been
submerged in sea water for 24 hours at 70.degree. F..+-.5.degree.
F. (21.degree. C..+-.2.8.degree. C.). The flexible ballistic armor
of the invention is also preferably characterized in retaining at
least about 85%, more preferably at least about 90% of its V.sub.50
performance after immersion in tap water at 70.degree.
F..+-.5.degree. F. (21.degree. C..+-.2.8.degree. C.) for 20 hours
when impacted with a 17 grain fragment simulated projectile (fsp).
Under these conditions, the flexible ballistic armor also exhibits
a weight increase of preferably not more than 50%, and more
preferably not more than about 40% from its dry weight. Moreover,
the flexible ballistic armor of the invention preferably is
characterized in retaining at least about 85%, more preferably at
least about 90%, of its V.sub.50 performance after immersion in
gasoline at 70.degree. F..+-.5.degree. F. (21.degree.
C..+-.2.8.degree. C.) for 4 hours, when impacted with a 16 grain
projectile.
[0056] The following non-limiting examples serve to illustrate the
invention.
Example 1
[0057] The ballistic performance of a three-panel, woven
aramid/non-woven aramid/woven aramid hybrid flexible shoot pack was
tested against a 9 mm, 129 grain FMJ bullet. The panels were tack
stitched together at the four corners of the shoot pack. The length
and width of the flexible shoot pack was 15''.times.15'' (38.1
cm.times.38.1 cm) with a thickness of about 1/2'' (12.7 mm). The
test standard was Military Standard MIL-STD-662F. Each woven aramid
layer was aramid Style 706 in a plain weave fabric construction
(600 denier; pick count: 34.times.34 ends/inch (2.54 mm); areal
weight: 180 g/m.sup.2), commercially available from Hexcel
Corporation of Stamford, Conn., and was formed from Kevlar.RTM. KM2
fibers, available from E. I. du Pont de Nemours and Company of
Wilmington, Del. Each non-woven aramid layer was Gold Shield.RTM.
GN 2115, (water-based thermoplastic polyurethane matrix; areal
weight: 112 g/m.sup.2) commercially available from Honeywell
International, Inc. of Morristown, N.J. The total areal weight of
the shoot pack was 1.09 lb/ft.sup.2 (5320 g/m.sup.2). Accordingly,
the total shoot pack content of Style 706 woven aramid was
approximately 75% by weight, and the total shoot pack content of
Gold Shield.RTM. GN 2115 was about 25% by weight. The test results
for the hybrid shoot pack is summarized in Table 1 below.
Example 2
[0058] A similar three-panel hybrid shoot pack as described in
Example 1 was tested against a 2 grain Right Circular Cylinder
fragment. The test standard was Military Standard MIL-STD-662F. The
data is summarized in Table 1 below.
Example 3
[0059] A similar three-panel hybrid shoot pack as described in
Example 1 was tested against a 4 grain Right Circular Cylinder
fragment. The test standard was Military Standard MIL-STD-662F. The
data is summarized in Table 1 below.
Example 4
[0060] A similar three-panel hybrid shoot pack as described in
Example 1 was tested against a 16 grain Right Circular Cylinder
fragment. The test standard was Military Standard MIL-STD-662F. The
data is summarized in Table 1 below.
Example 5
[0061] A similar three-panel hybrid shoot pack as described in
Example 1 was tested against a 64 grain Right Circular Cylinder
fragment. The test standard was Military Standard MIL-STD-662F. The
data is summarized in Table 1 below.
Example 6
[0062] A similar three-panel hybrid shoot pack as described in
Example 1 was tested against a 17 grain Fragment Simulated
Projectile fragment. The test standard was Military Standard
MIL-STD-662F. The data is summarized in Table 1 below.
Example 7
[0063] A similar three-panel hybrid shoot pack as described in
Example 1 was tested against a 16 grain Right Circular Cylinder
fragment after soaking the shoot pack for 4 hours in gasoline,
followed by drip-drying for 15 minutes. The test standard was
Military Standard MIL-STD-662F. The data is summarized in Table 1
below.
Example 8
[0064] A similar three-panel hybrid shoot pack as described in
Example 1 was tested against a 2 grain Right Circular Cylinder
fragment after soaking the shoot pack in sea water for 24 hours,
followed by drip-drying for 15 minutes. The test standard was
Military Standard MIL-STD-662F. The data is summarized in Table
1.
TABLE-US-00001 TABLE 1 V50 Example (ft/sec) Number Material Layers
(fps) 1 Hybrid of Style 706 + 11 + 12 + 11 1636 GN 2115 + Style 706
2 Hybrid of Style 706 + 11 + 12 + 11 2591 GN 2115 + Style 706 3
Hybrid of Style 706 + 11 + 12 + 11 2531 GN 2115 + Style 706 4
Hybrid of Style 706 + 11 + 12 + 11 2147 GN 2115 + Style 706 5
Hybrid of Style 706 + 11 + 12 + 11 1766 GN 2115 + Style 706 6
Hybrid of Style 706 + 11 + 12 + 11 2034 GN 2115 + Style 706 7
Hybrid of Style 706 + 11 + 12 + 11 1977 GN 2115 + Style 706 8
Hybrid of Style 706 + 11 + 12 + 11 2348 GN 2115 + Style 706
Example 9
[0065] The ballistic performance of an un-soaked three-panel, woven
aramid/non-woven aramid/woven aramid hybrid flexible shoot pack was
tested against a 2 grain Right Circular Cylinder fragment. The
panels were tack stitched together at the four corners of the shoot
pack. The length and width of the flexible shoot pack was
15''.times.15'' (38.1 cm.times.38.1 cm) with a thickness of about
1/2'' (12.7 mm). The shoot pack construction included a non-woven
panel having 24 layers of Gold Shield.RTM. GN 2115 sandwiched
between two woven panels, each woven panel having 7 layers of woven
aramid Style 706. The test standard was Military Standard
MIL-STD-662F. The total areal weight of the shoot pack was 1.09
lb/ft.sup.2 (5320 g/m.sup.2). Accordingly, the total shoot pack
content of Style 706 woven aramid was approximately 50% by weight,
and the total shoot pack content of Gold Shield.RTM. GN 2115 was
about 50% by weight. The test results for the hybrid shoot pack is
summarized in Table 2 below.
Example 10
[0066] A similar three-panel hybrid shoot pack as described in
Example 9 was tested against a 2 grain Right Circular Cylinder
fragment after soaking in sea water for 24 hours, followed by
drip-drying for 15 minutes. The test standard was Military Standard
MIL-STD-662F. The test results for the hybrid shoot pack is
summarized in Table 2 below.
Example 11
[0067] A similar un-soaked three-panel hybrid shoot pack as
described in Example 9 was tested against a 4 grain Right Circular
Cylinder fragment. The test standard was Military Standard
MIL-STD-662F. The test results for the hybrid shoot pack is
summarized in Table 2 below.
Example 12
[0068] A similar three-panel hybrid shoot pack as described in
Example 9 was tested against a 4 grain Right Circular Cylinder
fragment after soaking in sea water for 24 hours, followed by
drip-drying for 15 minutes. The test standard was Military Standard
MIL-STD-662F. The test results for the hybrid shoot pack is
summarized in Table 2 below.
Example 13
[0069] A similar un-soaked three-panel hybrid shoot pack as
described in Example 9 was tested against a 16 grain Right Circular
Cylinder fragment. The test standard was Military Standard
MIL-STD-662F. The test results for the hybrid shoot pack is
summarized in Table 2 below.
Example 14
[0070] A similar three-panel hybrid shoot pack as described in
Example 9 was tested against a 16 grain Right Circular Cylinder
fragment after soaking in sea water for 24 hours, followed by
drip-drying for 15 minutes. The test standard was Military Standard
MIL-STD-662F. The test results for the hybrid shoot pack is
summarized in Table 2 below.
Example 15
[0071] A similar un-soaked three-panel hybrid shoot pack as
described in Example 9 was tested against a 64 grain Right Circular
Cylinder fragment. The test standard was Military Standard
MIL-STD-662F. The test results for the hybrid shoot pack is
summarized in Table 2 below.
Example 16
[0072] A similar three-panel hybrid shoot pack as described in
Example 9 was tested against a 64 grain Right Circular Cylinder
fragment after soaking in sea water for 24 hours, followed by
drip-drying for 15 minutes. The test standard was Military Standard
MIL-STD-662F. The test results for the hybrid shoot pack is
summarized in Table 2 below.
TABLE-US-00002 TABLE 2 V50 Example Shoot Pack Soaked in (ft/sec)
Number Construction Sea Water Layers (fps) 9 Hybrid of Style 706 +
No 7 + 24 + 7 2634 GN 2115 + Style 706 10 Hybrid of Style 706 + Yes
7 + 24 + 7 2474 GN 2115 + Style 706 11 Hybrid of Style 706 + No 7 +
24 + 7 2450 GN 2115 + Style 706 12 Hybrid of Style 706 + Yes 7 + 24
+ 7 2107 GN 2115 + Style 706 13 Hybrid of Style 706 + No 7 + 24 + 7
2138 GN 2115 + Style 706 14 Hybrid of Style 706 + Yes 7 + 24 + 7
1906 GN 2115 + Style 706 15 Hybrid of Style 706 + No 7 + 24 + 7
1776 GN 2115 + Style 706 16 Hybrid of Style 706 + Yes 7 + 24 + 7
1572 GN 2115 + Style 706
Example 17
[0073] The ballistic performance of a three-panel, woven
aramid/non-woven aramid/woven aramid hybrid flexible shoot pack was
tested against a 2 grain Right Circular Cylinder fragment after
soaking in sea water for 24 hours, followed by drip-drying for 15
minutes. The panels were tack stitched together at the four corners
of the shoot pack. The length and width of the flexible shoot pack
was 15''.times.15'' (38.1 cm.times.38.1 cm) with a thickness of
about 1/2'' (12.7 mm). The shoot pack construction included a
non-woven panel having 12 layers of Gold Shield.RTM. GN 2115
sandwiched between two woven panels comprising aramid Style 751 in
a plain weave construction (600 denier; pick count: 29.times.29
ends/inch (2.54 mm); areal weight: 152.6 g/m.sup.2 (4.5
oz/yd.sup.2)) which is formed from Kevlar.RTM. KM2 fibers and is
commercially available from Hexcel Corporation of Stamford, Conn.,
with each woven panel comprising 13 layers of aramid style 751. The
test standard was Military Standard MIL-STD-662F. The total areal
weight of the shoot pack was 1.07 lb/ft.sup.2 (5320 g/m.sup.2).
Accordingly, the total shoot pack content of Style 751 woven aramid
was approximately 76% by weight, and the total shoot pack content
of Gold Shield.RTM. GN 2115 was about 24% by weight. The test
results for the hybrid shoot pack is summarized in Table 3
below.
Example 18
[0074] A similar three-panel hybrid shoot pack as described in
Example 17 was tested against a 4 grain Right Circular Cylinder
fragment after soaking in sea water for 24 hours, followed by
drip-drying for 15 minutes. The test standard was Military Standard
MIL-STD-662F. The test results for the hybrid shoot pack is
summarized in Table 3 below.
Example 19
[0075] A similar three-panel hybrid shoot pack as described in
Example 17 was tested against a 16 grain Right Circular Cylinder
fragment after soaking in sea water for 24 hours, followed by
drip-drying for 15 minutes. The test standard was Military Standard
MIL-STD-662F. The test results for the hybrid shoot pack is
summarized in Table 3 below.
Example 20
[0076] A similar three-panel hybrid shoot pack as described in
Example 17 was tested against a 64 grain Right Circular Cylinder
fragment after soaking in sea water for 24 hours, followed by
drip-drying for 15 minutes. The test standard was Military Standard
MIL-STD-662F. The test results for the hybrid shoot pack is
summarized in Table 3 below.
TABLE-US-00003 TABLE 3 V50 Example (ft/sec) Number Material Layers
(fps) 17 Hybrid of Style 751 + 13 + 12 + 13 2606 GN 2115 + Style
751 18 Hybrid of Style 751 + 13 + 12 + 13 2385 GN 2115 + Style 751
19 Hybrid of Style 751 + 13 + 12 + 13 2087 GN 2115 + Style 751 20
Hybrid of Style 751 + 13 + 12 + 13 2650 GN 2115 + Style 751
Example 21
[0077] The ballistic performance of a three-panel, woven
aramid/non-woven aramid/woven aramid hybrid flexible shoot pack was
tested against a 2 grain Right Circular Cylinder fragment after
soaking in sea water for 24 hours, followed by drip-drying for 15
minutes. The panels were tack stitched together at the four corners
of the shoot pack. The length and width of the flexible shoot pack
was 15''.times.15'' (38.1 cm.times.38.1 cm) with a thickness of
about 1/2'' (12.7 mm). The shoot pack construction included a
non-woven panel having 17 layers of Gold Shield.RTM. GN 2115
sandwiched between two woven panels comprising aramid Style 751,
commercially available from Hexcel Corporation of Stamford, Conn.,
with each woven panel comprising 11 layers of aramid style 751.
[0078] The test standard was Military Standard MIL-STD-662F. The
total areal weight of the shoot pack was 1.07 lb/ft.sup.2 (5320
g/m.sup.2). Accordingly, the total shoot pack content of Style 751
woven aramid was approximately 65% by weight, and the total shoot
pack content of Gold Shield.RTM. GN 2115 was about 35% by weight.
The test results for the hybrid shoot pack is summarized in Table 4
below.
Example 22
[0079] A similar three-panel hybrid shoot pack as described in
Example 21 was tested against a 4 grain Right Circular Cylinder
fragment after soaking in sea water for 24 hours, followed by
drip-drying for 15 minutes. The test standard was Military Standard
MIL-STD-662F. The test results for the hybrid shoot pack is
summarized in Table 4 below.
Example 23
[0080] A similar three-panel hybrid shoot pack as described in
Example 21 was tested against a 16 grain Right Circular Cylinder
fragment after soaking in sea water for 24 hours, followed by
drip-drying for 15 minutes. The test standard was Military Standard
MIL-STD-662F. The test results for the hybrid shoot pack is
summarized in Table 4 below.
Example 24
[0081] A similar three-panel hybrid shoot pack as described in
Example 21 was tested against a 64 grain Right Circular Cylinder
fragment after soaking in sea water for 24 hours, followed by
drip-drying for 15 minutes. The test standard was Military Standard
MIL-STD-662F. The test results for the hybrid shoot pack is
summarized in Table 4 below.
TABLE-US-00004 TABLE 4 V50 Example (ft/sec) Number Material Layers
(fps) 21 Hybrid of Style 751 + 11 + 17 + 11 2738 GN 2115 + Style
751 22 Hybrid of Style 751 + 11 + 17 + 11 2360 GN 2115 + Style 751
23 Hybrid of Style 751 + 11 + 17 + 11 2014 GN 2115 + Style 751 24
Hybrid of Style 751 + 11 + 17 + 11 1706 GN 2115 + Style 751
[0082] The above examples collectively illustrate that the hybrid
shoot packs retain excellent ballistic resistance properties even
after being soaked in either seawater or gasoline.
[0083] While the present invention has been particularly shown and
described with reference to preferred embodiments, it will be
readily appreciated by those of ordinary skill in the art that
various changes and modifications may be made without departing
from the spirit and scope of the invention. It is intended that the
claims be interpreted to cover the disclosed embodiment, those
alternatives which have been discussed above and all equivalents
thereto.
* * * * *