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United States Patent |
5,202,167
|
Harpell
,   et al.
|
April 13, 1993
|
Flexible composites having rigid isolated panels and articles fabricated
from same
Abstract
A flexible article of manufacture especially suitable for use as a
ballistic resistant body armor which comprises one or more composite
layers, at least one of said composite layers comprising a base layer
having a plurality of planar bodies positioned between two sandwiching
flexible layers out of contact with each other and a plurality of planar
bodies positioned on a surface of said base layer out of contact with each
other and in disalignment with the sandwiched planar bodies.
Inventors:
|
Harpell; Gary A. (Morristown, NJ);
Prevorsek; Dusan C. (Morristown, NJ);
Gerlach; Max W. (Hackettstown, NJ)
|
Assignee:
|
Allied-Signal Inc. (Morristown, NJ)
|
Appl. No.:
|
705682 |
Filed:
|
May 24, 1991 |
Intern'l Class: |
F16B 002/00 |
Field of Search: |
428/33,76,246,252,284,286,902,911,53,113,105,109,110,196
|
References Cited
U.S. Patent Documents
3557384 | Jan., 1971 | Barron et al. | 2/2.
|
3577836 | May., 1971 | Tamura | 428/911.
|
3894472 | Jul., 1975 | Davis | 428/911.
|
4241457 | Dec., 1980 | Klein | 428/911.
|
4356569 | Nov., 1982 | Sullivan | 428/911.
|
4403012 | Sep., 1983 | Harpell et al. | 428/911.
|
4413110 | Nov., 1983 | Kavesh et al. | 428/911.
|
4443506 | Apr., 1984 | Schmolmann | 428/911.
|
4457985 | Jul., 1984 | Harpell et al. | 428/911.
|
4535478 | Aug., 1985 | Zafle | 2/2.
|
4543286 | Sep., 1985 | Harpell et al. | 428/911.
|
4559251 | Dec., 1985 | Wachi | 428/911.
|
4608717 | Sep., 1986 | Dunbavand | 428/911.
|
4613535 | Sep., 1986 | Harpell et al. | 428/911.
|
4623574 | Nov., 1986 | Harpell et al. | 428/911.
|
4650710 | Mar., 1987 | Harpell et al. | 428/911.
|
4660223 | Apr., 1987 | Fritch | 428/911.
|
4680812 | Jul., 1987 | Weigl | 428/911.
|
4681792 | Jul., 1987 | Harpell et al. | 428/911.
|
4737401 | Apr., 1988 | Harpell et al. | 428/911.
|
4737402 | Apr., 1988 | Harpell et al. | 428/911.
|
4748064 | May., 1988 | Harpell et al. | 428/911.
|
4810559 | Mar., 1989 | Fortier et al. | 428/196.
|
4916000 | Apr., 1990 | Li et al. | 428/911.
|
4923741 | May., 1990 | Kosmo et al. | 428/911.
|
5087516 | Feb., 1992 | Groves | 428/911.
|
5110661 | May., 1992 | Groves | 428/911.
|
Other References
J. Macromol. Sci.-Chem., A7(1), pp. 295-322 (1973), R. C. Liable and F.
Figucia.
|
Primary Examiner: Bell; James J.
Attorney, Agent or Firm: Stewart, II; R. C., Fuchs; G. H., Webster; D. L.
Claims
What is claimed is:
1. A flexible composite comprising one or more composite layers, at least
one of said composite layers comprising at least two flexible layers each
of which comprises a plurality of rigid planar bodies positioned on a
surface thereof out of contact with each other forming a pattern of
covered regions formed from said layers and said bodies and uncovered
regions formed from said flexible layers, said flexible layers positioned
such that the covered region of one flexible layer is in alignment with
said uncovered region of an adjacent flexible layer such that at least
about 85 area % of said uncovered of one flexible layer is aligned with
said planar bodies of an adjacent flexible layer.
2. A composite as recited in claim 1 wherein said surface planar bodies are
position such that said article has at least two semi-continuous or
continuous seams in which seam directions intersect at an angle.
3. A composite as recited in claim 2 wherein said article has at least
three seams.
4. A composite as recited in claim 3 wherein said seams are continuous.
5. A composite as recited in claim 4 wherein seam directions are at an
angle.
6. A composite as recited in claim 5 wherein said angle is about
60.degree..
7. A composite as recited in claim 1 wherein said composite comprises one
or more composite layers, at least one of said composite layers comprising
a plurality of first planar bodies fixed on a surface of a first flexible
layer or fixed between said first flexible layer and a second flexible
layer such that each of said first bodies is isolated from and out of
contact with each other of said first bodies forming a first base layer
having a pattern of filled regions formed from said first flexible layer
and said first bodies or formed from said first and second flexible layers
and said first bodies, and unfilled regions formed from said first
flexible layer or said first and second flexible layers, and a plurality
of second planar bodies on a surface of said base layer, or on a surface
of a third flexible layer, or fixed between said third flexible layer and
a fourth flexible layer forming a second base layer such that each of said
second planar bodies is isolated from and out of contact with each other
of said second planar bodies and each of said first planar bodies, said
second planar bodies positioned in correspondence and alignment with said
unfilled regions of such base layer such that at least about 85 area % of
said unfilled region is aligned with its corresponding second planar body.
8. A composite as recited in claim 7 wherein said first planar bodies and
said second planar bodies are formed from a penetration resistant
material.
9. A composite as recited in claim 8 wherein said first planar bodies, and
said second planar bodies are the same or different and are selected from
the group consisting of triangular shaped bodies, hexagonal shaped bodies
or a combination thereof.
10. A composite as recited in claim 9 wherein said triangular shaped bodies
are of equilateral triangular shape or substantially of equilateral
triangular shape.
11. A composite as recited in claim 10 wherein said first planar bodies and
said second planar bodies are of different shape.
12. A composite as recited in claim 11 wherein said first bodies are of
triangular shape and said second bodies are of hexagonal shape.
13. A composite as recited in claim 11 wherein said first bodies are of
hexagonal shape and said second bodies are of triangular shape.
14. A composite as recited in claim 7 wherein said first planar bodies and
said second planar bodies comprise repeats of three planar bodies, at
least one of said bodies being a first planar body and at least one of
said bodies being a second planar body.
15. A composite as recited in claim 12 wherein said first planar bodies and
said second planar bodies are of different shapes and are triangular
shaped, hexagonal shaped or a combination thereof.
16. A composite as recited in claim 13 wherein said at least one composite
layer comprises a plurality of first planar bodies fixed between said
first and second flexible layers forming said base layer having said
filled and unfilled regions.
17. A composite as recited in claim 14 wherein said second bodies cover at
least about 95 area percent of the surface area said unfilled regions.
18. A composite as recited in claim 16 wherein said second planar bodies
cover substantially about 100 area percent of the surface area of said
unfilled regions.
19. A composite as recited in claim 13 wherein said second planar bodies
are uniformly larger in surface area than said corresponding unfilled
regions and wherein said second planar bodies cover 100 area percent of
said unfilled regions.
20. A composite as recited in claim 17 wherein said composite comprises a
plurality of second planar bodies positioned on a surface of said first
base layer in alignment with said corresponding unfilled regions; or said
second planar bodies are fixed between said third and fourth flexible
layers forming a second base layer and wherein said first and second base
layers are positioned such that the second planar bodies positioned
between said third and fourth layers are in alignment with said
corresponding unfilled regions.
21. A composite as recited in claim 19 wherein said second planar bodies
are positioned on a surface of said first base layer.
22. A composite as recited in claim 20 wherein said first planar bodies and
said second planar bodies are positioned such that said bodies form
repeats of three bodies one of said bodies being a first planar body and
two of said bodies being a second planar body.
23. A composite as recited in claim 21 wherein said first planar bodies are
of a hexagonal shape, and said second planar bodies are of triangular
shape.
24. A composite as recited in claim 20 wherein said second planar bodies
are fixed between said third and fourth flexible layers.
25. A composite as recited in claim 23 wherein said first planar bodies and
said second planar bodies are positioned such that said bodies form
repeats of three bodies, one of said bodies being a first planar body and
two of said bodies being a second planar body.
26. A composite as recited in claim 25 wherein said first planar bodies are
of a hexagonal shape, and said second planar bodies are of triangular
shape.
27. A composite as recited in claim 26 wherein said first, second, third
and fourth flexible layers are the same or different and are comprise of a
network of fibers having a tensile strength of at least about 7
grams/denier, a tensile modulus of at least about 30 grams/denier and an
energy-to-break of at least about 30 joules/grams.
28. A composite as recited in claim 27 wherein said fibers have a tenacity
equal to or greater than about 10 g/d, a tensile modulus equal to or
greater than about 150 g/d and an energy-to-break equal to or greater than
about 10 j/g.
29. A composite as recited in claim 28 wherein said tenacity is equal to or
greater than about 20 g/d, said modulus is equal to or greater than about
500 g/d, and said energy-to-break is equal to or greater than about 15
j/g.
30. A composite as recited in claim 28 wherein said tenacity is equal to or
greater than about 25 g/d, said modulus is equal to or greater than about
1000 g/d, and said energy-to-break is equal to or greater than about 20
j/g.
31. A composite as recited in claim 20 wherein said fibers are polyethylene
fibers, glass fibers, polyester fibers, aramid fibers, nylon fibers or
mixtures thereof.
32. A composite as recited in claim 31 wherein said fibers are polyethylene
fibers.
33. A composite as recited in claim 31 wherein said fibers are aramid
fibers.
34. A composite as recited in claim 31 wherein said fibers are a
combination of polyethylene fibers and aramid fibers.
35. A composite as recited in claim 31 wherein at least one of said first,
second, third and fourth flexible layers are the same or different and
comprise at least one sheet-like fibers array in which said fibers are
arranged substantially parallel to one another along a common fiber
direction in a polymeric matrix.
36. A composite as recited in claim 35 wherein at least one of said first,
second, third and fourth flexible layers comprises more than one array,
with adjacent arrays aligned at an angle with respect to the common fiber
direction of the parallel fibers contained in said adjacent array.
37. A composite as recited in claim 36 wherein said angle is from about
45.degree. to about 90.degree..
38. A composite as recited in claim 37 wherein said angle is about
90.degree..
39. A composite as recited in claim 26 wherein at least one of said first,
second, third and fourth layers comprises a non-woven fabric.
40. A composite as recited in claim 26 wherein of least one of said first,
second, third and fourth layers as the same or different and comprise a
woven fabric.
41. A composite as recited in claim 7 further comprising a cover layer and
a backing layer sandwiching said one or more composite layers.
42. An article of manufacture fabricated totally or in part from the
composite of claim 1.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to flexible composites and to articles fabricated
from same having enhanced flexibility. A more preferred aspect of this
invention relates to flexible composites and articles having improved
protection against penetration by such threats as bullets, knives, ice
picks, flechettes and the like.
2. Prior Art
Since the beginning of recorded history, a combination of rigid plates or
panels affixed to a flexible backing, usually fabric or leather, has been
used extensively as body armor in diverse areas of the world. (Charles
Ffoulkes, Armour and Weapons Oxford at the Clarendar Press, 1909; H.
Russell Robinson, Armour, London: Herbert Jenkins, 1967; A. M. Snodgrass,
Arms and Armour of the Greeks, Cornell University Press, Ithaca, N.Y.,
1967; Vesey Norman, Arms and Armor, G. P. Putnam's Sons, New York and
Claude Blair, European Armous. The McMillan Company, New York, 1959.
During the 14th century a cloth or leather garment lined with metal
plates, known as a coat of plates, was the most widely used type of body
defence. It appears that the plates were rectangular in shape and their
arrangement prevented draping of the armor or flexing on the bias. Almost
certainly, this armor limited the mobility of the wearer. A development
from the coat of plates was the brigandine which remained in general use
until the 17th century. In the 15th century and later the brigandine
consisted of a coat of plates made of small lames which could work over
each other, thus producing flexible protection. A variant of the
brigandine, the jack, (15th century) consisted of many small plates of
iron or horn secured between layers of canvas by a trellis-work of
stitches. A variant of the jack was the "pennyplate coat" and was
constructed from small overlapping iron discs with each disc riveted to a
canvas backing. (See Claude Blair, European Armour, The MacMillan Company,
New York 1959)
Roy C. Laible, Ballistic Materials and Penetration Mechanics, Elsevier
Scientific Publishing Co. Amsterdam Oxford-New York, 1980 describes an
infantry vest utilizing 149 titanium plates attached to four layers of
nylon ballistic fabric backing. The plates overlapped and incorporated
three slits to allow them to slide, thus providing flexibility. The plates
were rectangular or square in shape and appear to be curved in one plane.
U.S. Pat. No. 4,316,286 describes a bullet-proof plate assemblies,
utilizing hinged plates, but such assemblies utilize relatively large
roughly rectangular shaped panels. Such an approach is unlikely to lead to
flexibility required for an infantry vest.
U.S. Pat. No. 4,559,251 describes a material for protective clothing which
has been developed based on an assembly of hexagonal rigid plates.
Although such a construction is an improvement over a single rigid panel
it appears that the structure will have inherent limitations in
flexibility, contrary to claims in the patent, which would limit its
usefulness as infantry body armor.
U.S. Pat. No. 4,483,020 describes a ballistic vest which incorporates
essentially square plates which interlock when flexed inward. It is
claimed that such an arrangement reduces blunt trauma. A similar vest is
disclosed in U.S. Pat. No. 4,660,223 which incorporates multiple titanium
panels with each titanium panel to each other except by overlying and
underlying felted material. In this disclosure, all panels appear to be
based on square or rectangular considerations.
A design for body armor has been disclosed in U.S. Pat. No. 4,535,478 in
which modular panels have been incorporated into a carrier garment. No
unusual geometric considerations were disclosed.
Multiple plate body armor has been disclosed in U.S. Pat. No. 4,680,812
which allows flexibility but protects the body from hyper-extension, thus
protecting against spinal injury.
Flexible body armor has been disclosed in U.S. Pat. No. 3,894,472 which has
a central support sheet with the plates arranged in a checkerboard
pattern. The pattern of the plates on one face are the reverse of the
pattern on the opposite face. This approach claims complete coverage by
rigid plates, coupled with appropriate flexibility.
An infantry body armor system has been disclosed in U.S. Pat. No. 3,557,384
which is claimed to provide protection against both fragments and small
arms fire. This system uses a single plate on the front of the torso and a
single plate on the back of the torso to provide protection against small
arms fire. Relatively large plates may be utilized on a limited and
specific portions of the torso.
A complex body armor system has been disclosed in U.S Pat. No. 3,577,836
which incorporates multiple Telflon discs which are circular when viewed
from the front but are elliptical in cross-section. It is claimed that the
low coefficient of friction facilitates the deflection of projectiles and
the elliptical cross-section minimizes the number of projectiles which can
impact normal to the disc surface.
Ballistic articles such as bulletproof vests, helmets, structural members
of helicopters and other military equipment, vehicle panels, briefcases,
raincoats and umbrellas containing high strength fibers are known. Fibers
conventionally used include aramid fibers such as poly(phenylenediamine
terephthalamide), graphite fibers, nylon fibers, ceramic fibers, glass
fibers and the like. For many applications, such as vests or parts of
vests, the fibers are used in a woven or knitted fabric. For many of the
applications, the fibers are encapsulated or embedded in a matrix
material.
U.S. Pat. Nos. 4,623,574 and 4,748,064 disclose a simple composite
structure comprising high strength fibers embedded in an elastomeric
matrix. The simple composite structure exhibits outstanding ballistic
protection as compared to simple composites utilizing rigid matrices, the
results of which are disclosed in the patents. Particularly effective are
simple composites employing ultra-high molecular weight polyethylene and
polypropylene such as disclosed in U.S. Pat. No. 4,413,110.
U.S. Pat. Nos. 4,737,402 and 4,613,535 disclose complex rigid composite
articles having improved impact resistance which comprise a network of
high strength fibers such as the ultra-high molecular weight polyethylene
and polypropylene disclosed in U.S. Pat. No. 4,413,110 embedded in an
elastomeric matrix material and at least one additional rigid layer on a
major surface of the fibers in the matrix. It is disclosed that the
composites have improved resistance to environmental hazards, improved
impact resistance and are unexpectedly effective as ballistic resistant
articles such as armor.
U.S. Pat. No. 4,650,710 discloses a flexible article of manufacture
comprising a plurality of first flexible layers arranged in a first
portion of the article, each of said first layers consisting essentially
of fibers having a tensile modulus of at least about 300 g/denier and a
tenacity of at least about 15 g/denier and a tenacity of at least about 15
g/denier and a plurality of a second flexible layers arranged in a second
portion of said article, each of said second flexible layers comprising
fibers, the resistance to displacement of fibers in each of said second
flexible layers being greater than the resistance to displacement in each
of said first flexible layers.
Other ballistic resistant articles are described in U.S. Pat. Nos.
4,916,000; 4,403,012, 4,457,985; 4,737,401; 4,543,286; 4,563,392 and
4,501,856.
SUMMARY OF THE INVENTION
The present invention relates to flexible composites and to articles of
manufacture fabricated therefrom. The composite of this invention
comprises one or more composite layers, at least one of said layers
comprising a plurality of first planar bodies fixed on a surface of a
first flexible layer or fixed between said first flexible layer and a
second flexible layer such that each of said first bodies is isolated from
and out of contact with each other of said first bodies forming a base
layer having a pattern of filled regions formed from said first flexible
layer and said first bodies or formed from said first and second flexible
layers and said first bodies, and unfilled regions formed from said first
flexible layer or said first and second flexible layers, and a plurality
of second planar bodies on a surface of said base layer, or on a surface
of a third flexible layer, or fixed between said third flexible layer and
a fourth flexible layer such that each of said second planar bodies is
isolated from and out of contact with each other of said second planar
bodies and each of said first planar bodies, said second planar bodies
positioned in correspondence and alignment with said unfilled regions of
said base layer such that at least about 85 area %, preferably at least
about 90 area %, more preferably at least about 95 area % and most
preferably about 100 area % of said unfilled regions are aligned with said
second planar bodies.
Another aspect of the invention relates to articles of manufacture
fabricated totally or in part from the composite of this invention.
Several advantages flow from this invention. In general, the composite of
this invention provides for a high degree of flexibility even though it
includes substantial rigid portions. Furthermore, because the planar
bodies or rigid areas are isolated, noise is minimized.
In those embodiments of the invention where the planar bodies are made of
penetration resistant materials, and the composite or article is intended
to provide penetration resistance, a high degree of coverage by the
penetration resistant bodies is provided. Moreover, the composite or
article of this invention exhibits relatively improved penetration
resistance as compared to fibrous composites of the same areal density
without unduly affecting the flexibility of the composite adversely. The
use of the composite layer construction provides a high degree of
versatility in the amount of overlap of first and second planar bodies to
provide varying degrees of penetration protection. Furthermore, through
use of the composite or article of this invention, relatively higher
denier yarn can be employed in the manufacture of the various flexible
layers of the composite or article of this invention without unduly
affecting the penetration resistance of the composite or article. The
penetration resistance properties of the composites or articles of this
invention may be optimized such that the first and second planar bodies
blunt sharp penetration threats such as flechettes, ice picks and the like
to increase the effectiveness of any penetration resistant backing layer
that may be used.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be more fully understood and further advantages will
become apparent when reference is made to the following detailed
description of the invention and the accompanying drawings in which:
FIG. 1 is a depiction of Drape Test 1 for evaluation of the flexibility of
a composite of this invention.
FIG. 2 is a depiction of Drape Test 2 for evaluation of the flexibility of
the composite of this invention.
FIG. 3 is a front perspective view of a preferred embodiment of the article
of this invention.
FIG. 4 is a front perspective view of the embodiment of FIG. 3 having
certain selected components cut away for purpose of illustration.
FIG. 5 is an enlarged fragmentary sectional view of the body armor of this
invention of FIG. 4 taken on line 4--4'.
FIG. 6 is an enlarged fragmental sectional view of another body armor of
this invention of the type depicted in FIG. 4 taken on line 4--4' showing
detached elements of base layer.
FIG. 7 is an enlarged fragmental sectional view of another body armor of
this invention of the type depicted in FIG. 4 taken on line 4--4' showing
detached elements of base layer.
FIG. 8 is an enlarged fragmental sectional view of another body armor of
this invention of the type depicted in FIG. 4 taken on line 4--4' showing
detached elements of base layer 18 showing the arrangement of hexagonal
planar bodies 26 between layers 28 and 30, the arrangement of triangular
surface bodies 24 on the bottom surface of cover layer 14 and the
arrangement of triangular suface bodies 24 on the top surface of backing
layer 16.
FIG. 9 is an enlarged sectional view of another body armor similar to that
of FIG. 4 taken along line 4--4' showing the attachment of planar bodies
24 to unfilled regions 22 by way of spacers 22(a).
FIG. 10 is a fragmentary sectional view of a body armor of this invention
similar to that of FIG. 4 taken along line 4--4' in which surface bodies
40 are attached to layer 38.
FIG. 11 is an enlarged fragmentary sectional view of a body armor of this
invention similar to that of FIG. 4 taken along line 4--4' which comprises
at least two base layers 18(a) and 18(b) in which layers 18(a) and 18(b)
are aligned such that filled regions of layer 18(a) are aligned with
unfilled regions 22 of adjacent layer 18(b) and the unfilled regions of
layer 18 (a) are aligned with the filled regions of adjacent layer 18(b).
FIG. 12 is a fragmentary overview of the arrangement of FIG. 4 in alignment
as positioned in article 10 showing the extent of coverage by the
combination of hexagonal shaped first bodies A and triangular shaped
second bodies B and C.
FIG. 13 to 20 are preferred planar bodies for use in the practice of this
invention.
FIG. 21 is a schematic of a linearly truncated triangular planar body on a
fabric grid for use in composite of Example 1 to reduce contact between
adjacent triangular bodies.
FIG. 22 is a depiction of the arrangement of triangular shaped bodies sewn
onto both sides of a fabric layer in composite 1 of Example 1.
FIG. 23 is a schematic of a non-linearly truncated triangular planar body
which reduces the amount of the fabric layer not covered by the planar
body for use in the composites of Example 1.
FIG. 24 is a depiction of the arrangement of triangular and hexagonal
planar bodies in composite 3.
FIG. 25 is a depiction of the arrangement of triangular shaped bodies in
comparison composite 1 of Example 1.
FIG. 26 is a depiction of the arrangement of triangular and hexagonal
shaped bodies in composites 7 and 8 of Example 1.
FIG. 27 is a depiction of the arrangement of hexagonal shaped bodies and
triangular shaped unfilled regions of the composite 9.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION
The preferred invention will be better understood by those of skill in the
art by reference to the above figures. For convenience, the composite of
this invention and the article of this invention are described in terms of
certain preferred embodiments. The preferred embodiments of this invention
illustrated in the figures are not intended to be exhaustive or to limit
the invention to the precise form disclosed. It is chosen to describe or
to best explain the principles of the invention and its application and
practical use to thereby enable others skilled in the art to best utilize
the invention.
In its broadest aspects, the invention is directed to a composite
comprising at least one flexible substrate having a plurality of planar
bodies affixed to a surface thereof and to articles fabricated therefrom.
In the preferred embodiments of the invention, the composite, of this
invention and articles fabricated therefrom exhibit improved penetration
resistance when said composite and/or article is impacted by a projectile
as a weapon such as a knife, icepick, shrapnel, flechette, flying glass or
the like without adversely affecting the flexibility of the composite or
article to an undue extent.
As used herein, the "penetration resistance" of the composite or article is
the resistance to penetration by a designated threat, as for example, a
bullet, an ice pick, a knife or the like. The penetration resistance can
be expressed as the ratio of peak force (F) for designated threat
(projectile, velocity, and other threat parameters known to those of skill
in the art to affect peak force) divided by the areal density (ADT) of the
target. As used herein, the "peak force", is the maximum force exerted by
a threat to penetrate a designated target using a model 1331 high speed
Instron Tester having an impact velocity of about 12 ft/sec (3.66 m/sec)
and where the target strike face area has a diameter of 3 in. (7.6 cm) and
as used herein, the "areal density" or "ADT" is the ratio of total target
weight to the area of the target.
In general, the flexibility of the composite of the present invention can
be demonstrated by Drape Test 1. In this test, a 30 cm square sample of
the composite is placed onto a flat surface horizontally along one side
edge with an overhang of 20 cm as shown in FIG. 1 and the amount of drape
of the composite (the amount of drape being measured by the distance
between the level of the clamped side edge and the opposite edge) is
measured. The initial test is carried out with composite panel sides
parallel to the edge and designated 0 degrees. The ratio of drop of the
unsupported side, h or drape, to the distance of overhang, 1, is taken as
a measure of the flexibility. The panel is rotated through various angles,
and the flexibility measured in a similar manner. (The relationship of
panel orientation to angle designation is shown in FIG. 1.) For flexible
composite of this invention, the amount of drape in Drape Test 1 is
ordinarily at least about 8 cm, preferably at least about 10 cm, more
preferably at least about 13 cm and most preferably at least about 17 cm.
In the preferred embodiments of the invention the composite is flexible
according to Drape Test 2. In this test, a square sample of the composite
is draped around a cylinder (OD=4 inches (10.2 cm) and affixed with rubber
bands as shown in FIG. 2. The ratio of the drop to the overhang was taken
as a measure of flexibility. (See FIG. 2). This test is used to supplement
Drape Test 1 in the preferred embodiments of the invention because it was
noted that flexibility after flexing in one plane varied markedly with
different panels.
Referring to FIGS. 3 and 4, the numeral 10 indicates a penetration
resistant article 10, which in the preferred embodiments of the invention
is penetration resistant body armor. As depicted in the embodiment of FIG.
5, article 10 is comprised of one or more penetration resistant composite
layers 12(a) and 12(b), cover layer 14 and backing layer 16. The of
composite layers 12 included in article 10 of this invention may vary
widely depending on the use of the composite, for example, for those uses
where article 10 would be used as penetration protection, the number of
composite layers 12 would depend on a number of factors including the
degree of penetration protection desired and other factors known to those
of skill in the penetration protection art. In general for this
application, the greater the degree of penetration protection desired the
greater the number of composite layers 12 included in article 10 for a
given weight of the article. Conversely, the lesser the degree of
penetration protection required, the lesser the number of composite layer
12 required for a given weight of article 10. As depicted in FIG. 5,
article 10 is comprised of two penetration resistant composite layers 12a
to 12b. However, the number of composite layers included in article 10 may
vary widely, provided that at least one layer 15 is present. In general,
the number of composite layers 12 in any embodiment will vary depending on
the degree of penetration resistance and flexibility desired. The number
of composite layers 12 is preferably from 1 to about 10, more preferably
from about 1 to about 5 and most preferably from about 1 to about 2.
As depicted in FIGS. 5, 6 and 7 in vertical cross-section, article 10 is
comprised of cover layer 14, penetration resistant composite layers 12(a)
and 12(b) and backing layer 16. As depicted in the FIGS. 5 and 6,
penetration resistant composite layers 12(a) and 12(b) comprise a base
layer 18 having filled regions 20 and unfilled regions 22, and surface
planar bodies 24 which cover unfilled regions 22. Base layer 18 is formed
by sandwiching planar bodies 26 between flexible layers 28 and 30. The
position of sandwiched planar bodies 26 is substantially fixed. The manner
in which bodies 26 are fixed may vary widely. For example, bodies 26 may
be fixed by fixation to one or both of flexible layers 28 and 30. Any
fixation means can be employed. For example, bodies 26 may be secured by
bolts, rivets, adhesives, staples, stitches and the like. Bodies 26 may be
affixed by direct attachment. For example, bodies 26 may be attached
directly to one or more surfaces of flexible layers 28 and 30 by some
suitable method as for example by directly bolting, gluing or sewing same
to layer 28 and/or 30 at one or more points of attachment. Bodies 26 may
also be fixed indirectly by isolation in a pocket formed from layers 28
and 30. For example, bodies 26 may be fixed within a pocket by tieing
layers 28 and 30 together about all or a portion of the outer
circumference of bodies 26 by some suitable means as for example,
stitches, adhesives, bolts and the like to form filled regions 20. The
relative positions and fixations of bodies 26 between layers 28 and 30 is
such that filled regions 20 and unfilled regions 22 are formed.
Penetration resistant composite layer 12 is formed by fixation of surface
planar bodies 24 to one or more surfaces of base panel 18 preferably such
that at least about 85 area %, preferably at least about 90 area %, more
preferably at least about 95 area % and most preferably at least about 100
area % of unfilled regions 22 of resistant layer 12 are covered by surface
planar bodies 24.
Surface planar bodies 24 may be affixed or secured to one or another
surface of base layer 18 by any conventional means. Means for attaching
planar bodies 24 to a surface of base layer 18 may vary widely and may
include any means normally used in the art to provide this function.
Illustrative of useful attaching means are adhesives such as those
discussed in R. C. Liable, Ballistic Materials and Penetration Mechanics,
Elsevier Scientific Publishing Co. (1980). Illustrative of other useful
attaching means are bolts, screws, staples mechanical interlocks,
stitching, or a combination of any of these conventional methods. As
depicted in FIGS. 2 and 6 to 14 in the preferred embodiments of the
invention planar bodies 24 are stitched to the surface of base layer 18 by
way of stitches or optionally, the stitching may be supplemented by an
adhesive.
As shown in FIGS. 5, 6 and 7, unfilled regions 22 are formed by securing
flexible layers 28 and 30 together forming a layered region 22 comprised
of two or more layers. Any conventional securing means may be used
including but not limited to bolts, rivets, adhesive, staples, stitches,
and the like. In the preferred embodiments of the invention securing means
is adhesive, lamination in those instances when layers 28 and 30 are
formed of a laminatable material, stitches or a combination thereof.
In the preferred embodiments of the invention depicted in FIGS. 3 and 4,
where layers 28 and 30 are fibrous, horizontal stitches and vertical
stitches (not depicted) are utilized to secure substrate layers 28 and 30.
The type of stitching employed may vary widely. Stitching and sewing
methods such as lock stitching, chain stitching, zig-zag stitching and the
like are illustrative of the type of stitching for use in this invention.
The nature of the stitching fiber will vary widely and any type of fiber
may be used. Useful stitching threads and fibers may vary widely and will
be described in more detail herein below in the discussion of fiber for
use in the fabrication of layers 28 to 30. In those embodiments of the
invention where layers 28 and 30 are not relied on for penetration
resistance the tensile modulus and tenacity of the fiber may vary from
very low to very high. However, in those embodiments of the invention
where layers 28 to 30 contribute to the penetration resistance of article
10 fibers having a relatively high tensile modulus and tenacity are
employed. In these embodiments, it has been found that a relatively high
modulus (equal to or greater than about 200 grams/denier) and a relatively
high tenacity (equal to or greater than about 5 grams/denier) fiber is
advantageous when layers 28 and 30 contribute to the pentration resistance
of article 10. All tensile properties are evaluated by pulling a 10 in
(25.4 cm) fiber length clamped in barrel clamps at a rate of 10 in/min
(25.4 cm/min) on an Instron Tensile Tester. In the preferred embodiments
of the invention, the tensile modulus is from about 400 to about 3000
grams/denier and the tenacity is from about 20 to about 50 grams/denier,
more preferably the tensile modulus is from about 1000 to about 3000
grams/denier and the tenacity is from about 25 to about 50 grams/denier
and most preferably the tensile modulus is from about 1500 to about 3000
grams/denier and the tenacity is from about 30 to about 50 grams/denier.
However, the thread or fiber used in stitching means is preferably an
aramid fiber or thread (as for example Kevlar.RTM. 29, 49, 29 and 149
aramid fibers), an extended chain polyethylene thread or fiber (as for
example Spectra.RTM. 900 and Spectra.RTM. 1000 polyethylene fibers) or a
mixture thereof.
Layers 30 and 28 may vary widely, the only requirement is that they be
flexible as defined above. For example, layers 28 and 30 may be a flexible
polymer or elastomeric film formed from a thermoplastic or elastomeric
resin. Such thermoplastic and elastomeric resins for use in the practice
of this invention may vary widely. Illustrative of useful thermoplastic
resins are polylactones such as poly(pivalolactone),
poly(.epsilon.-caprolactone) and the like; polyurethanes derived from
reaction of diisocyanates such as 1,5-naphalene diisocyanate, p-phenylene
diisocyanate, m-phenylene diisocyanate, 2,4-toluene diisocyanate,
4',4'-diphenylmethane diisocyanate,
3,3'-dimethyl-4,4'-diphenylisopropylidiene diisocyanate,
3,3'-dimethyl-4,4'-diphenyl diisocyanate,
3,3'-dimethyl-4,4'-dephenylmethane diisocyanate,
3,3'-dimethyoxy-4,4'-biphenyl diisocyanate, dianisidine diisocyanate,
tolidine diisocyanate, hexamethylene diisocyanate,
4,4-diisocyananodiphenylmethane and the like and linear long-chain diols
such as poly(tetramethylene adipate), poly(ethylene adipate),
poly(1,4-butylene adipate), poly(ethylene adipate), polyether diols and
the like; polycarbonates such as poly[1,1-ether bis(4-phenyl carbonate)],
poly[1,1-ether bis(4-phenyl) carbonate], poly[diphenylmethane bis
(4-phenyl) carbonate], poly[1,1-cyclohexane bis (4-phenyl) carbonate],
poly[1,1-cyclohexane bis(4-phenyl carbonate]and the like; poly sulfones;
polyether ether ketones; polymides such as poly(4-amino butyric acid),
poly(hexamethylene adipamide), poly(6-aminohexanoic acid), poly(m-xylylene
adipamide), poly(p-xylylene sebacamide), poly 2,2,2-trimethyl
hexamethylene terephthalamide),
poly(metaphenyleneisophthalamide)(Nomex.RTM.), poly(p-phenylene
terephthalamide) (Kevlar.RTM.), and the like; polyesters such as
poly(ethylene azelate), poly(ethylene-1,5-naphthalate), poly(ethylene
oxybenzoate) (A-Tell), poly(ethylene oxybenzoate) (A-Tell),
poly(para-hydroxy benzoate) (Ekonol), poly(1,4-cyclohexylidene dimethylene
terephthalate) (Kodel)(as), poly(1,4-cyclohexylidene dimethylene
terephthalate) (Kodel)(trans), polyethylene terephthalate terephthalate
and the like; poly(arylene oxides) such as poly(2,6-diphenyl-1,4-phenylene
oxide), poly(2,6-diphenyl-1,4-phenylene oxide) and the like; poly(arylene
sulfides) such as poly(phenylene sulfide) and the like; polyetherimides;
thermoplastic elastomers such as polyurethane elastomers,
fluoroelastomers, butadiene/acrylonitrule elastomers, block copolymers,
made up of segments of glassy or crystalline blocks such as polystyrene,
poly(vinyl-toluene), poly(t-butyl styrene), polyester and the like and the
elastomeric blocks such as polybutadiene, polyisoprene, ethylene-propylene
copolymers, ethylene-butylene copolymers, polyether ester and the like as
for example the copolymers in polystyrene-polybutadiene- polystrene block
copolymer manufactured by Shell Chemical Company under the trade name of
Kraton.RTM.; vinyl polymer and their copolymers such as polyvinyl acetate,
polyvinyl alcohol, polyvinyl chloride, polyvinyl butyral, polyvinylidene
chloride, ethylene-vinyl acetate copolymers, and the like; polyacrylics,
polyacrylate and their copolymers such as polyethyl acrylate, poly(n-butyl
acrylate), poly(methylmethacrylate), polyethyl methacrylate, poly(n-butyl
methacrylate), polyacrylamide, polyacrylonitrile, polyacrylic acid,
ethyleneacrylic acid copolymers, methyl methacrylate-styrene copolymers,
ethyleneethyl acrylate copolymers, methacrylated butadiene-styrene
copolymers and the like; polyolefins such as low density polyethylene,
polyolefins such as low density polyethylene, polypropylene, chlorinated
low desity polyethlene, poly(4-methyl-1-pentene) and the like; ionomers;
and polyepichlorohydrins; polycarbonates and the like.
Layers 28 and 30 may also comprise a network of fibers either alone or
dispersed in a matrix. For purposes of the present invention, fiber is
defined as an elongated body, the length dimension of which is much
greater than the dimensions of width and thickness. Accordingly, the term
fiber as used herein includes a monofilament elongated body, a
multifilament elongated body, ribbon, strip, and the like having regular
or irregular cross sections. The term fibers includes a plurality of any
one or combination of the above.
The cross-section of fibers for use in this invention may vary widely.
Useful fibers may have a circular cross-section, oblong cross-section or
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. In the particularly preferred embodiments of the invention, the
fibers are of substantially circular or oblong cross-section and in the
most preferred embodiments are of circular or substantially circular
cross-section.
Layers 28 and 30 may be formed from fibers alone, or from fibers coated
with a suitable polymer, as for example, a polyolefin, polyamide,
polyester, polydiene such as a polybutadiene, urethanes, diene/olefin
copolymers, poly(styrene-butadienestyrene) block copolymers, and a wide
variety of elastomers. Layers 22 and 24 may also comprise a network of a
fibers dispersed in a polymeric matrix as for example a matrix of one or
more of the above referenced polymers to form a flexible composite as
described in more detail in U.S. Pat. Nos. 4,623,574; 4,748,064;
4,916,000; 4,403,012; 4,457,985; 4,650,710; 4,681,792; 4,737,401;
4,543,286; 4,563,392; and 4,501,856. Regardless of the construction,
layers 28 and 30 are such that article 10 has the required degree of
flexibility.
The fibers in layers 28 and 30 may be arranged in networks having various
configurations. For example, a plurality of fibers can be grouped together
to form twisted or untwisted yarn bundles in various alignments. The
filaments or yarn may be formed as a felt, knitted or woven (plain,
basket, satin and crow feet weaves, etc.) into a network, fabricated into
non-woven fabric, arranged in parallel array, layered, or formed into a
woven fabric by any of a variety of conventional techniques. Among these
techniques, for ballistic resistance applications we prefer to use those
variations commonly employed in the preparation of aramid fabrics for
ballistic-resistant articles. For example, the techniques described in
U.S. Pat. No. 4,181,768 and in M. R. Silyquist et al., J. Macromol Sci.
Chem., A7(1), pp. 203 et. seq. (1973) are particularly suitable.
The denier of the fiber may vary widely. In general, fiber denier is equal
to or less than about 4000. In the preferred embodiments of the invention,
fiber denier is from about 10 to about 4000, the more preferred
embodiments of the invention fiber denier is from about 10 to about 1000
and in the most preferred embodiments of the invention, fiber denier is
from about 10 to about 400.
The type of fibers used in the fabrication of layers 28 and 30 may vary
widely, may be inorganic or organic fibers. Useful inorganic fibers
include S-glass fibers, E-glass fibers, carbon fibers, boron fibers,
alumina fibers, zirconia-silica fibers, alumina-silica fibers and the
like.
Illustrative of useful organic fibers are those composed of polyesters,
polyolefins, polyetheramides, fluoropolymers, polyethers, celluloses,
phenolics, polyesteramides, polyurethanes, epoxies, aminoplastics,
polysulfones, polyetherketones, polyetheretherketones, polyesterimides,
polyphenylene sulfides, polyether acryl ketones, poly(amideimides), and
polyimides. Illustrative of other useful organic filaments are those
composed of aramids (aromatic polyamides), such as poly(m-xylylene
adipamide), poly(p-xylylene sebacamide), poly 2,2,2-trimethylhexamethylene
terephthalamide), poly(piperazine sebacamide), poly(metaphenylene
isophthalamide) (Nomex.RTM.) and poly(p-phenylene terephthalamide)
(Kevlar.RTM.); aliphatic and cycloaliphatic polyamides, such as the
copolyamide of 30% hexamethylene diammonium isophthalate and 70%
hexamethylene diammonium adipate, the copolyamide of up to 30%
bis-(amidocyclohexyl)methylene, terephthalic acid and caprolactam,
polyhexamethylene adipamide (nylon 66), poly(butyrolactam) (nylon 4), poly
(9-aminonoanoic acid) (nylon 9), poly(enantholactam) (nylon 7),
poly(capryllactam) (nylon 8), polycaprolactam (nylon 6), poly (p-phenylene
terephthalamide), polyhexamethylene sebacamide (nylon 6,10),
polyaminoundecanamide (nylon 11), polydodeconolactam (nylon 12),
polyhexamethylene isophthalamide, polyhexamethylene terephthalamide,
polycaproamide, poly(nonamethylene azelamide) (nylon 9,9),
poly(decamethylene azelamide) (nylon 10,9), poly(decamethylene sebacamide)
(nylon 10,10), bis-(4-aminocyclothexyl) methane
1,10-decanedicarboxamide](Qiana) (trans), or combination thereof; and
aliphatic, cycloaliphatic and aromatic polyesters such as
poly(1,4-cyclohexlidene dimethyl eneterephathalate) cis and trans,
poly(ethylene-1,5 -naphthalate), poly(ethylene-2,6-naphthalate), poly(1,4
-cyclohexane dimethylene terephthalate) (trans), poly(decamethylene
terephthalate), poly(ethylene terephthalate), poly(ethylene isophthalate),
poly(ethylene oxybenozoate), poly(para-hydroxy benzoate),
poly(dimethylpropiolactone), poly(decamethylene adipate), poly(ethylene
succinate), poly(ethylene azelate), poly(decamethylene sebacate),
poly(dimethylpropiolactone), and the like. Also illustrative of useful
organic fibers are those of liquid crystalline polymers such as lyotropic
liquid crystalline polymers which include polypeptides such as
poly-.alpha.-benzyl L-glutamate and the like; aromatic polyamides such as
poly(1,4-benzamide), poly(chloro-1,4-phenylene terephthalamide),
poly(1,4-phenylene fumaramide), poly(chloro-1,4-phenylene fumaramide),
poly(4,4'-benzanilide trans, transmuconamide), poly(1,4-phenylene
mesaconamide), poly(1,4-phenylene) (trans-1,4-cyclohexylene amide),
poly(chloro-1,4-phenylene) (trans-1,4-cyclohexylene amide),
poly(1,4-phenylene 1,4-dimethyl-trans-1,4-cyclohexylene amide),
poly(1,4-phenylene 2,5-pyridine amide), poly(chloro-1,4-phenylene
2,5-pyridine amide), poly(3,3'-dimethyl-4,4'-biphenylene 2,5-pyridine
amide), poly(chloro-1,4-phenylene 4,4'-stilbene amide), poly(1,4-phenylene
4,4'-azobenzene amide), poly(4,4'-azobenzene 4,4'-azobenzene amide),
poly(1,4-phenylene 4,4'-azoxybenzene amide), poly(4,4'-azobenzene
4,4'-azoxybenzene amide), poly(1,4-cyclohexylene 4,4'-azobenzene amide),
poly(4,4'-azobenzene terephthal amide), poly(3,8-phenanthridinone
terephthal amide), poly(4,4'-biphenylene terephthal amide),
poly(4,4'-biphenylene 4,4'-bibenzo amide), poly(1,4-phenylene 4,4'-bibenzo
amide), poly(1,4-phenylene 4,4'-terephenylene amide), poly(1,4-phenylene
2,6-naphthal amide), poly(1,5-naphthylene terephthal amide),
poly(3,3'-dimethyl-4,4-biphenylene terephthal amide),
poly(3,3'-dimethoxy-4,4'-biphenylene terephthal amide),
poly(3,3'-dimethoxy-4,4 -biphenylene 4,4'-bibenzo amide) and the like;
polyoxamides such as those derived from 2,2'-dimethyl-4,4'diamino biphenyl
and chloro-1,4-phenylene diamine; polyhydrazides such as poly
chloroterephthalic hydrazide, 2,5-pyridine dicarboxylic acid hydrazide)
poly(terephthalic hydrazide), poly(terephthalicchloroterephthalic
hydrazide) and the like; poly(amide-hydrazides) such as poly(terephthaloyl
1,4-amino-benzhydrazide) and those prepared from 4-amino-benzhydrazide,
oxalic dihydrazide, terephthalic dihydrazide and para-aromatic diacid
chlorides; polyesters such as those of the compositions include
poly(oxy-trans-1,4
-cyclohexyleneoxycarbonyl-trans-1,4-cyclohexylenecarbonyl-.beta.-oxy-1,4-p
henyl-eneoxyterephthaloyl) and
poly(oxy-cis-1,4-cyclohexyleneoxycarbonyl-trans-1,4-cyclohexylenecarbonyl-
.beta.-oxy-1,4-phenyleneoxyterephthal oyl) in methylene chloride-o-cresol
poly[(oxy-trans-1,4-cyclohexylene-oxycarbonyl-trans-1,4
-cyclohexylenecarbonyl-.beta.-oxy-(2-methyl-1,4-phenylene)
oxy-terephthaloyl)] in 1,1,2,2-tetrachloro-ethane-o-chlorophenol-phenol
(60:25:15 vol/vol/vol), poly[oxy-trans-
1,4-cyclohexyleneoxycarbonyl-trans-1,4-cyclohexylenecarbonyl-.beta.-oxy(2-
methyl-1,3-phenylene)oxy-terephthaloyl] in o-chlorophenol and the like;
polyazomethines such as those prepared from 4,4'-diaminobenzanilide and
terephthaldehyde, methyl-1,4-phenylenediamine and terephthalaldehyde and
the like; polyisocyanides such as poly(-phenyl ethyl isocyanide),
poly(n-octyl isocyanide) and the like; polyisocyanates such as
poly(n-alkyl isocyanates) as for example poly(n-butyl isocyanate),
poly(n-hexyl isocyanate) and the like; lyotropic crystalline polymers with
heterocylic units such as poly(1,4-phenylene-2,6-benzobisthiazole) (PBT),
poly(1,4-phenylene- 2,6-benzobisoxazole) (PBO),
poly(1,4-phenylene-1,3,4-oxadiazole),
poly(1,4-phenylene-2,6-benzobisimidazole), poly[2,5(6)-benzimidazole]
(AB-PBI), poly[2,6-(1,4-phenylene)-4-phenylquinoline],
poly[1,1'-(4,4'-biphenylene)-6,6'-bis(4-phenylquinoline)] and the like;
polyorganophosphazines such as polyphosphazine, polybisphenoxyphosphazine,
poly[bis(2,2,2'-trifluoroethyelene) phosphazine] and the like; metal
polymers such as those derived by condensation of
trans-bis(tri-n-butylphosphine) platinum dichloride with a bisacetylene or
trans-bis(tri-n-butylphosphine)bis(1,4-butadienyl)platinum and similar
combinations in the presence of cuprous iodine and an amide; cellulose and
cellulose derivatives such as esters of cellulose as for example
triacetate cellulose, acetate cellulose, acetate-butyrate cellulose,
nitrate cellulose, and sulfate cellulose, ethers of cellulose as for
example, ethyl ether cellulose, hydroxymethyl ether cellulose,
hydroxypropyl ether cellulose, carboxymethyl ether cellulose, ethyl
hydroxyethyl ether cellulose, cyanoethylethyl ether cellulose,
ether-esters of cellulose as for example acetoxyethyl ether cellulose and
benzoyloxypropyl ether cellulose, and urethane cellulose as for example
phenyl urethane cellulose; thermotropic liquid crystalline polymers such
as celluloses and their derivatives as for example hydroxypropyl
cellulose, ethyl cellulose propionoxypropyl cellulose, thermotropic liquid
crystalline polymers such as celluloses and their derivatives as for
example hydroxypropyl cellulose, ethyl cellulose propionoxypropyl
cellulose; thermotropic copolyesters as for example copolymers of
6-hydroxy-2-naphthoic acid and p-hydroxy benzoic acid, copolymers of
6-hydroxy-2-naphthoic acid, terephthalic acid and p-amino phenol,
copolymers of 6-hydroxy-2-naphthoic acid, terephthalic acid and
hydroquinone, copolymers of 6-hydroxy-2-naphthoic acid, p-hydroxy benzoic
acid, hydroquinone and terephthalic acid, copolymers of 2,6-naphthalene
dicarboxylic acid, terephthalic acid, isophthalic acid and hydroquinone,
copolymers of 2,6-naphthalene dicarboxylic acid and terephthalic acid,
copolymers of p-hydroxybenzoic acid, terephthalic acid and
4,4'-dihydoxydiphenyl, copolymers of p-hydroxybenzoic acid, terephthalic
acid, isophthalic acid and 4,4'-dihydroxydiphenyl, p-hydroxybenzoic acid,
isophthalic acid, hydroquinone and 4,4'-dihydroxybenzophenone, copolymers
of phenylterephthalic acid and hydroquinone, copolymers of
chlorohydroquinone, terephthalic acid and p-acetoxy cinnamic acid,
copolymers of chlorohydroquinone, terephthalic acid and ethylene
dioxy-4,4'-dibenzoic acid, copolymers of hydroquinone, methylhydroquinone,
p-hydroxybenzoic acid and isophthalic acid, copolymers of (1
-phenylethyl)hydroquinone, terephthalic acid and hydroquinone, and
copolymers of poly(ethylene terephthalate) and p-hydroxybenzoic acid; and
thermotropic polyamides and thermotropic copoly(amide-esters).
Also illustrative of useful organic filaments for use in the fabrication of
substrate layer 14 are those composed of extended chain polymers formed by
polymerization of .alpha.,.beta.-unsaturated monomers of the formula:
R.sub.1 R.sub.2 --C.dbd.CH.sub.2
wherein R.sub.1 and R.sub.2 are the same or different and are
hydrogen,hydroxy, halogen, alkylcarbonyl, carboxy, alkoxycarbonyl,
heterocycle or alkyl or aryl either unsubstituted or substituted with one
or more substituents selected from the group consisting of alkoxy, cyano,
hydroxy, alkyl and aryl. Illustrative of such polymers of
.alpha.,.beta.-unsaturated monomers are polymers including polystyrene,
polyethylene, polypropylene, poly(1-octadecene), polyisobutylene,
poly(1-pentene), poly(2-methylstyrene), poly(4-methylstyrene),
poly(1-hexene), poly(1-pentene), poly(4-methoxystrene),
poly(5-methyl-1-hexene), poly(4-methylpentene), poly (1-butene), polyvinyl
chloride, polybutylene, polyacrylonitrile, poly(methyl pentene-1),
poly(vinyl alcohol), poly(vinyl-acetate), poly(vinyl butyral), poly(vinyl
chloride), poly(vinylidene chloride), vinyl chloride-vinyl acetate
chloride copolymer, poly(vinylidene fluoride), poly(methyl acrylate,
poly(methyl methacrylate), poly(methacrylo-nitrile), poly(acrylamide),
poly(vinyl fluoride), poly(vinyl formal), poly(3-methyl-1-butene),
poly(1-pentene), poly(4-methyl-1-butene), poly(1-pentene),
poly(4-methyl-1-pentene, poly(1-hexane), poly(5-methyl-1-hexene),
poly(vinyl-cyclopentane), poly(vinylcyclothexane),
poly(a-vinyl-naphthalene), poly(vinyl methyl ether),
poly(vinyl-ethylether), poly(vinyl propylether), poly(vinyl carbazole),
poly(vinyl pyrolidone), poly(2-chlorostyrene), poly(4-chlorostyrene),
poly(vinyl formate), poly(vinyl butyl ether), poly(vinyl octyl ether),
poly(vinyl methyl ketone), poly(methyl-isopropenyl ketone),
poly(4-phenylstyrene) and the like.
In general, the particular material employed in any particular situation
will depend to a large extent on the extent to which layers 28 and 30
contributed to the penetration resistance of the article. For example, in
those embodiments where layers 28 and 30 do not contribute to the
penetration resistance to any significant extent and are used primarily to
position planar bodies 26 and 24, generally any kind of material can be
used. On the other hand where layers 28 and 30 are intended to contribute
to the penetration resistance of the article, penetration resistant
materials are used. In those embodiments of the invention where layers 28
and 30 are penetration resistant, layers 28 and 30 are preferrably a
fibrous network such as a woven or non-woven fabric or a fibrous net work
in a polymeric matrix. Preferred fibers for use in the practice of this
invention are those having a tenacity equal to or greater than about 10
grams/denier (g/d) (as measured by an Instron Tensile Testing machine), a
tensile modulus equal to or greater than about 150 g/d (as measured by an
Instron Tensile Testing machine) and an energy-to-break equal to or
greater than about 8 joules/gram. Particularly preferred fibers are those
having a tenacity equal to or greater than about 20 g/d, a tensile modulus
equal to or greater than about 500 g/d and energy-to-break equal to or
greater than about 30 joules/grams. Amongst these particularly preferred
embodiments, most preferred are those embodiments in which the tenacity of
the fibers is equal to or greater than about 25 g/d, the tensile modulus
is equal to or greater than about 1000 g/d, and the energy-to-break is
equal to or greater than about 35 joules/gram. In the practice of this
invention, filaments of choice have a tenacity equal to or greater than
about 30 g/d, the tensile modulus is equal to or greater than about 1300
g/d and the energy-to-break is equal to or greater than about 40
joules/gram.
In the most preferred embodiments of the invention, article 10 includes
sandwiching layers 28 and 30, which may include polyethylene fibers,
polypropylene fibers, nylon fibers, polyester fibers, liquid crystal
copolyester fibers, aramid fibers, polyvinyl alcohol fibers,
polyacrylonitrile fibers or mixtures thereof. U.S. Pat. No. 4,457,985
generally discusses such high molecular weight polyethylene and
polypropylene fibers, and the disclosure of this patent is hereby
incorporated by reference to the extent that it is not inconsistent
herewith. In the case of polyethylene, suitable fibers are those of
molecular weight of at least 150,000, 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 as described in U.S.
Pat. No. 4,137,394 or U.S. Pat. No. 4,356,138 or fibers spun from a
solution to form a gel structure, as described in German Off. 3,004,699
and GB 2051667, and especially described in U.S. Pat. No. 4,457,985 (see
EPA 64,167, published Nov. 10, 1982). As used herein, the term
polyethylene shall mean a predominantly linear polyethylene material that
may contain minor amounts of chain branching or comonomers not exceeding 5
modifying units per 100 main chain carbon atoms, and that may also contain
admixed therewith not more than about 50 wt % of one or more polymeric
additives such as alkene-1-polymers, in particular low density
polyethylene, polypropylene or polybutylene, copolymers containing
mono-olefins as primary monomers, oxidized polyolefins, graft polyolefin
copolymers and polyoxymethylenes, or low molecular weight additives such
as anti-oxidants, lubricants, ultra-violet screening agents, colorants and
the like which are commonly incorporated by reference. Depending upon the
formation technique, the draw ratio and temperatures, and other
conditions, a variety of properties can be imparted to these fibers. The
tenacity of the fibers should be at least 15 grams/denier (as measured by
an Instron Testing Machine), preferably at least 20 grams/denier, more
preferably at least 25 grams/denier and most preferably at least 30
grams/denier. Similarly, the tensile modulus of the fibers, as measured by
an Instron Tensile Testing Machine, is at least 300 grams/denier,
preferably at least 500 grams/denier and more preferably at least 1,000
grams/denier and most preferably at least 1,200 grams/denier. These
highest values for tensile modulus and tenacity are generally obtainable
only by employing solution grown or gel fibers processes.
Similarly, highly oriented polypropylene fibers of molecular weight at
least 200,000, preferably at least one million and more preferably at
Ieast two million may be used. Such high molecular weight polypropylene
may be formed into reasonably well oriented fibers by the techniques
prescribed in the various references referred to above, and especially by
the technique of U.S. Pat. No. 4,551,296 and commonly assigned. Since
polypropylene is a much less crystalline material than polyethylene and
contains pendant methyl groups, tenacity values achievable with
polypropylene are generally substantially lower than the corresponding
values for polyethylene. Accordingly, a suitable tenacity is at least 8
grams/denier (as measured by an Instron Tensile Testing Machine), with a
preferred tenacity being at least 11 grams/denier. The tensile modulus for
polypropylene is at least 160 grams/denier, preferably at least 200
grams/denier. The particularly preferred ranges for the above-described
parameters can advantageously provide improved performance in the final
article.
High molecular weight polyvinyl alcohol fibers having high tensile modulus
are described in U.S. Pat. No. 4,440,711, which is hereby incorporated by
reference to the extent it is not inconsistent herewith. In the case of
polyvinyl alcohol (PV-OH), PV-OH fiber of molecular weight of at least
about 200,000. Particularly useful PV-OH fiber should have a tensile
modulus of at least about 300 g/d (as measured by an Instron Tensile
Testing Machine), a tenacity of at least 7 g/d (preferably at least about
10 g/d, more preferably at about 14 g/d, and most preferably at least
about 17 g/d), and an energy-to-break of at least about 8 joules/gram.
PV-OH fibers having a weight average molecular weight of at least about
200,000, a tenacity of at least about 10 g/d, a tensile modulus of at
least about 300 g/d, and an energy-to-break of about 8 joules/gram are
more useful in producing a ballistic resistant article. PV-OH fiber having
such properties can be produced, for example, by the process disclosed in
U.S. Pat. No. 4,599,267.
In the case of polyacrylonitrile (PAN), PAN fibers of molecular weight of
at least about 400,000. Particularly useful PAN fibers should have a
tenacity least about 8 joules/gram. PAN fibers having a least about 8
joules/gram. PAN fibers having a molecular weight of at least about
400,000, a tenacity of at least about 15 to about 20 g/d and an
energy-to-break of at least 8 joules/gram is most useful in producing
ballistic resistant articles; and such fibers are disclosed, for example,
in U.S. Pat. No. 4,535,027.
In the case of aramid fibers, suitable aramid fibers formed principally
from aromatic polyamide are described in U.S. Pat. No. 3,671,542, which is
hereby incorporated by reference. Preferred aramid fiber will have a
tenacity of at least about 20 g/d (as measured by an Instron Tensile
Testing Machine), a tensile modulus of at least about 400 g/d (as measured
by an Instron Tensile Testing Machine) and an energy-to-break at least
about 8 joules/gram, and particularly preferred aramid fiber will have a
tenacity of at least about 20 g/d, a modulus of at least about 480 g/d and
an energy-to-break of at least about 20 joules/gram. Most preferred aramid
fibers will have a tenacity of at least about 20 g/denier, a modulus of at
least about 900 g/denier and an energy-to-break of at least about 30
joules/gram. For example, poly(phenylene terephthalamide) fibers produced
commercially by Dupont Corporation under the trade name of Kevlar.RTM. 29,
49, 129 and 149 having moderately high moduli and tenacity values are
particularly useful in forming ballistic resistant composites. Also useful
in the practice of this invention is poly(metaphenylene isophthalamide)
fibers produced commercially by Dupont under the tradename Nomex.RTM..
In the case of liquid crystal copolyesters, suitable fibers are disclosed,
for example, in U.S. Pat. Nos. 3,975,487; 4,118,372; and 4,161,470, hereby
incorporated by reference. Tenacities of about 15 to about 30 g/d (as
measured by an Instron Tensile Testing Machine) and preferably about 20 to
about 25 g/d, and tensile modulus of about 500 to 1500 g/d (as measured by
an Instron Tensile Testing Machine) and preferably about 1000 to about
1200 g/d are particularly desirable.
In the case of nylon fibers, suitable fibers include those formed from
nylon 6, nylon 6,6, nylon 6, 10 and the like. Suitable polyester fibers
include poly(ethylene terephthalate).
As shown in the Figures, the position of planar bodies 24 and the manner in
which they are positioned such that each planar body is isolated from each
other planar body can vary widely and planar bodies 24 and 26 are
positioned such that the desired degree of coverage of the area to be
protected is provided. Preferably 100% area coverage or substantially 100%
area coverage is provided. More preferably, as depicted in FIGS. 8 and 9,
planar bodies 24 and 26 are positioned such that they overlap by some
portion 32(a). For example, as depicted in FIGS. 5, 6, 7, 8 and 9 base
layer 18 includes a plurality of planar bodies 30 affixed to one or more
surfaces of base layer 18 in total Or partial alignment with unfilled
region 22. As depicted in FIG. 6, planar bodies 24 may be affixed to the
same side of base layer 18 or as depicted in FIG. 7, planar bodies 24 may
be affixed to different sides of base layer 18. Alternatively, as shown in
FIG. 9, planar bodies 24 may be attached to different sides of base layer
18 to unfilled region 22 by way of spacers 22(a) which allow overlap of
planar bodies 24 and filled region 20. In yet another variation as shown
in FIG. 8, planar bodies 24 may be affixed to cover layer 14 and/or to
backing layer 16 in alignment with unfilled regions 22.
The use of planar bodies 24 and 26 enhances the pentration resistance of
article 10. As a penetrating threat such as a bullet, knife, ice pick,
flechette or the like, impacts a planar body 24 or 26, the threat can be
broken, bent, enlarged and/or flattened to increase its impact area and
decrease the velocity of the threat.
Means for attaching planar bodies 24 to base panel 18 may Vary widely and
may include any means normally used in the art to provide this function.
Illustrative of useful attaching means are adhesives such as those
discussed in R. C. Liable, Ballistic Materials and Penetration Mechanics,
Elsevier Scientific Publishing Co. (1980). Illustrative of other useful
attaching means are bolts, screws, staples mechanical interlocks,
stitching, or a combination of any of these conventional methods. In the
preferred embodiments of the invention, planar bodies 24 are stitched to
the surface of base layer 18 by way of stitches (not depicted).
Optionally, the stitching may be supplemented by or replaced adhesive. As
shown in FIGS. 5, 6, 7, 8 and 9 the plurality of planar bodies 24 are
positioned on the surfaces of base layer 18 such that unfilled areas 28
are totally or partially covered by a planar bodies 24 affixed to one or
both surfaces of area 22. As shown in FIGS. 5, 6, 7, 8 and 9 the plurality
of planar bodies 24 are positioned such that the, planar bodies 24 are in
alignment with unfilled regions 22. In the preferred embodiments of the
invention depicted in FIG. 8 and 9, each planar body 24 is uniformly
larger than its corresponding unfilled region 22 such that planar bodies
24 adjacent to an unfilled region 22 partially overlap with the adjacent
filled regions 20 by some portion 32. The degree of overlap may vary
widely, but in general is such that preferably more than about 90 area %,
more preferably more than about 95 area % and most preferably more than
about 100 area % of unfilled regions 22 covered by its corresponding
planar body 24.
FIG. 12 is a depiction showing the relative positions of surface planar
bodies 24 and sandwiched planar bodies 26 in the embodiment of FIG. 5 in
which layers 14, 16, 28 and 30 are removed to illustrate the degree of
coverage. As depicted FIG. 12 (which is an overhead view of the embodiment
of FIG. 5 with layers 20 and 22 removed), the relative positions of the
planar bodies provide for a high degree of surface coverage. Sandwiched
hexagonal planar bodies 26 are identified by A, the surface triangular
planar bodies 24 adjacent to cover layer 14 are identified by C and
triangular planar bodies 24 adjacent to backing layer 16 are identified by
B. In the preferred embodiments of the invention depicted in FIGS. 5 to
11, planar bodies 24 and 26 cover at least about 85 area percent of its
corresponding unfilled region 22. The coverage is such that preferably
more than about 90 area %, more preferably more than about 95 area % and
most preferably about 100% of one or both surfaces of unfilled region 22
is covered by its corresponding planar body 24. In the embodiments of
choice, planar body 24 is uniformly larger than its corresponding unfilled
region 22 such that overlap of planar bodies 24 and 26 in filled region 20
occurs. This overlap insures that area 100 area % coverage of the desired
area is provided and the area % coverage is not substantially reduced due
to disalignment of planar bodies 24 and corresponding unfilled regions 22.
As shown in the Figures, the position of planar bodies 24 can vary widely.
For example, planar bodies 24 may be on both surfaces base layer 18 or on
only one surface of layer 18 or may be affixed to the surfaces of cover
layer 14 and/or backing layer 16 by way of eyes 48. (See FIGS. 13 to 20).
However, in all cases bodies 24 are positioned that no body 24 directly
contacts another body 24 or a sandwiched body 26. The result is (as
depicted in FIGS. 6, 7 and 8) substantial coverage of the area to be
protected by bodies 24 and 26. At the same time this construction provides
a significant reduction in noise when the article is used due to the lack
of contact between planar bodies. Another major advantage of this
arrangement is that varying degrees of overlap by bodies 24 and 26 can be
achieved to provide improved protection. As depicted in FIGS. 5 to 8,
planar bodies 24 are preferably space filling and are positioned to
provide more than one, preferably two or three and more preferably at
least three flexible semi-continuous or continuous seams (preferably
continuous over the area to be protected) in different directions which
preferably intersect at an angle with each other (preferably at an angle
of about from about 30 to about 150.degree. more preferably at an angle of
from about 60 to about 120.degree. , and most preferably at an angle of
60.degree. with at least one other seam) in order to allow flexing in
multiple directions along the seams.
The number of planar bodies 24 may vary widely, the only requirement is
that for the area being protected there is at least one planar body 24
bound to a surface of each unfilled region 22 within the area to be
protected.
The shape of planar bodies 24 and the area percent of layer 18 covered by
planar bodies 24 may vary widely and will generally depend on the shape
and positioning of sandwiched bodies 26 and unfilled regions 22. As shown
in FIGS. 6, 7 and 8, this is preferably accomplished by dividing planar
bodies 24 and 26 covering a particular area to be protected into repeat
units composed of three planar bodies in which at least one planar body is
a sandwiched planar body 26 and in which at least one planar body is a
surface planar body 24, wherein the surface planar bodies 24 are of a size
and shape and are positioned such that they completely or partially cover
a unfilled area 22. For example, as depicted in FIG. 6, one element is
constrained between layers 28 and 30 by some suitable means as for
example, sewing, lamination, gluing or the like to form a filled region 20
sandwiched planar body 26. Surface planar bodies 24 are positioned on the
surface of base layer 18 on both sides of filled region 24. Alternatively,
as depicted in FIG. 7 planar bodies 24 can be positioned on opposite sides
of base layer 18, or two elements may be contrained between layers 28 and
30 (not depicted).
In the preferred embodiments of the invention, the repeat unit is formed by
sub-dividing a larger body into three smaller bodies. As depicted in FIG.
12, the repeat unit comprises triangular shaped planar surface bodies B
and C, and sandwiched hexagonal shaped planar body A. As can be readily
seen, this repeat unit is formed by sub-dividing various larger bodies
which can be sub-divided into at least two triangular shaped bodies and
one hexagonal shaped body. Such larger bodies include trapezoid,
parallogram or other shaped bodies.
For many applications where relatively high penetration resistance and
flexibility are desired, such as a ballistic resistant vest, it is
desirable to affix planar bodies 24 to base layer 18 such that the desired
flexibility is obtained. As shown in the Figures, this is preferably
accomplished by affixing planar bodies 24 as discontinuous geometric
shapes. In these applications, it is preferred that the planar bodies 24
as well as planar bodies 26 include penetration resistant structures
formed from rigid ballistic resistant materials. Preferred geometric
shapes will be space filling and will provide three different directions
for continuous or semi continuous (preferably continuous) seams, where
seam directions are preferably at an angle to each other (more preferably
at an angle of about 60.degree.) in order to allow flexing in multiple
directions. Such constructions regardless of the thickness and rigidity of
planar bodies 24 and planar bodies 26 can drape around doubly curved
surfaces and thus exhibit the desired flexibility. Primarily because of
the improved flexibility, a preferred construction consists of an
arrangement of triangular shaped bodies (preferably right angle triangles,
equilateral triangles or a combination thereof and more preferably
equilateral triangles) (See FIGS. 13, 14, 15 and 16) which are arranged to
be space filling and are positioned such that three flexible continuous
seams are formed which intersect at 60.degree. along which article 10 can
flex. As depicted in FIG. 12, a more preferred modification to this
construction is the inclusion of compatible geometric shapes such as
hexagons, parallelograms, trapezoids and the like, (especially hexagons
(See FIGS. 17, 18, 19 and 20)) which correspond to shapes obtainable by
fusion of two or more triangles at appropriate edges, or shaped bodies
which are formed by sub-dividing such compatible geometric shapes. As
depicted in FIG. 12 the most preferred compatible geometric shape is a
hexagon (See FIGS. 17 to 20}. The use of combinations of equilateral
triangles and hexagons where at least one body is between two flexible
layers and at least one body is on a surface of the two layers as depicted
in FIGS. 5 and 12 is flexible layers and at least one body is on a surface
of the two layers as depicted in FIGS. 5 and 12 is especially preferred
because of the reduced number of seams as compared to composites were the
bodies all are triangular shaped. The result is better protection with
substantially no reduction in flexiblity. It should be noted that while in
FIG. 5 the hexagonal shaped sandwiched bodies 26 are positioned between
layers 28 and 30, and triangular shaped surface bodies 24 are positioned
on the same side of base layer 18, such positioning is not critical to the
reduction in the number of seams when a combination of triangular and
hexagonal shaped bodies are used. The relative positioning of such bodies
can be conveniently changed provided that bodies are spaced apart out of
contact one from the other, and further provided that the desired degree
of protection is provided. (See FIGS. 7 to 11) . Such space filling
constructions allow a wide range of compromises between flexibility and
minimization of seams and penetration resistance. Planar bodies 24
preferably include eyes (not depicted) for stitching planar bodies 24 to a
surface of layer 18 by way of stitches.
As depicted in FIGS. 13, 15, 16, 17, 18 and 20 an alternative to
discontinuous relatively inflexible geometric shapes is the use of
relatively rigid penetration resistant surface planar bodies 24 and/or 26
containing flexible seams 46, such as slits, hinges, creases, perforations
and the like, which allow planar bodies 24 and/or 26 to flex along
flexible seams 46 relative to the plane of base layer 18. The use of
flexible seams 46 can provide for enhanced ballistic protection while at
the same time increasing the flexibility of the ballistic article to a
significant extent. It is desirable that flexible seams 46 of that
flexible seams 46 of each body combine to provide one, two or three or
more continuous or semi-continuous seams along more than one seam 46 of
planar bodies 24 and/or 26 along which article 10 can easily flex, in an
analogous manner to that described previously for those embodiments of the
invention having inflexible planar bodies 24 and 26 which are positioned
such that article 10 can flex along one or more continuous or semi
continous seams.
Planar bodies 24 and 26 are preferably comprised of a rigid material which
may vary widely depending on the uses of article 10. The term "rigid" as
used in the present specification and claims is intended to include
semi-flexible and semi-rigid structures that are capable of being free
standing, without collapsing, or in other words materials which are not
flexible in Drape Test 1 as described above. Any rigid material can be
used in the practice of this invention to form planar bodies 24 and 26
including inorganic materials, such as metals or ceramics, or organic
materials such as polymer films, woven and non-woven fabrics, composites
and the like of varying thicknesses and rigidities.
For the preferred embodiments of the invention where the composite is
penetration resistant the materials employed in the fabrication of planar
bodies 24 and 26 may vary widely and may be any penetration resistant
material. Ilustrative of such materials are those described in G. S. Brady
and H. R. Clauser, Materials Handbook, 12th Ed. (1986). Useful materials
include high modulus thermosetting resins and thermoplastic polymers such
as polyamides as for example aramids, nylon-66, nylon-6 and the like;
polyesters such as polyethylene terephthalate, polybutylene terephthalate,
and the like; acetalo; polysulfones; polyethersulfones; polyacrylates;
acrylonitrile/butadiene/styrene copolymers; poly(amideimide);
polycarbonates; polyphenylenesulfides; polyurethanes; polyphenyleneoxides;
polyester carbonates polyesterimides; polyimides; polyetherimides;
polyesteramides; polyetheretherketone; epoxy resins; phenolic resins;
polysulfides; silicones; phenolic cyanate resins, polyacrylates;
polyacrylics; polydienes; vinyl ester resins, modified phenolic resins;
unsaturated polyester; allylic resins; alkyd resins, melamine and urea
resins; polymer alloys and blends one or more of thermoplastic resins
thermosetting resins and combinations one or more thereof; and
interpenetrating polymer networks such as those of polycyanate ester of a
polyol such as the dicyanoester of bisphenol-A and a thermoplastic such as
a polysulfone or polyethersulfone.
Planar bodies 24 and 26 may comprise a network of fibers as for example
those described for use in the fabrication of layers 20 and 22 preferably
aramid fibers, such as Kevlar.RTM. 29, 49, 129 and 149 aramid fibers,
polyethylene fibers such as Spectra.RTM. 900 and Spectra.RTM. 1000
polyethylene fibers and combinations thereof dispersed in a matrix of one
of more polymeric materials such as one or more thermoplastic resins one
or more thermosetting resins or a combination thereof, such as polymers
used to form the fibers of layers 20 and 22. In these embodiments of the
invention, the fibers are dispersed in a continuous phase of a matrix
material which preferably substantially coats each filament contained in
the fiber. The manner in which the filaments are dispersed may vary
widely. The filaments may be aligned in a substantially parallel,
unidirectional fashion, or filaments may by aligned in a multidirectional
fashion with filaments at varying angles with each other. In the preferred
embodiments of this invention, filaments in each layer are aligned in a
substantially parallel, unidirectional fashion such as in a prepreg,
pultruded sheet and the like. One such suitable arrangement is where the
polymeric layer comprises a plurality of layers or laminates in which the
coated filaments are arranged in a sheet-like array and aligned parallel
to one another along a common filament direction. Successive layers of
such coated, uni-directional filaments can be rotated with respect to the
previous layer to form a relatively flexible composite. An example of such
laminate structures are composites with the second, third, fourth and
fifth layers rotated +45.degree., -45.degree., 90.degree. and 0.degree.,
with respect to the first layer, but not necessarily in that order. Other
examples include composites with 0.degree./90.degree. layout of yarn or
filaments. Techniques for fabricating these laminated structures are
described in greater detail in U.S. Pat. Nos. 4,916,000; 4,623,574;
4,748,064; 4,457,985 and 4,403,012.
Useful materials for the fabrication of planar bodies 24 and 26 also
include multilayered fabric or fibrous composites in which the fabric or
fibrous layers are secured by some securing means as for example
stitching, adhesive, bolts, staples and the like. These fabrics can be
woven armor and can be formed from the fibers described above for use in
the fabrication of layers 20 and 22 such as glass fibers, aramid fibers
(such as Kevlar.RTM. 29, 49, 129 and 149 aramid fibers) polyethylene
fibers (such as Spectra.RTM. 900 and Spectra.RTM. 1000 polyethylene
fibers) and combinations thereof.
Planar bodies 24 and 26 may also be formed from metal and non-metal
ceramics. Illustrative of useful metal and non-metal ceramics are as those
described in C. F. Liable, Ballistic Materials and Penetration Mechanics,
Chapters 5-7 (1980) and include single oxides such as aluminum oxide
(Al.sub.2 O.sub.3), barium oxide (BaO), beryllium oxide (BeO), calcium
oxide (CaO), cerium oxide (Ce.sub.2 O.sub.3 and CeO.sub.2), chromium oxide
(Cr.sub.2 O.sub.3), dysprosium oxide (Dy.sub.2 O.sub.3), erbium oxide
(Er.sub.2 O.sub.3), europium oxide: (EuO, Eu.sub.2 O.sub.3, and Eu.sub.2
O.sub.4), (Eu.sub.16 O.sub.21), gadolinium oxide (Gd.sub.2 O.sub.3),
hafnium oxide (HfO.sub.2), holmium oxide (Ho.sub.2 O.sub.3), lanthanum
oxide (La.sub.2 O.sub.3), Iutetium oxide (Lu.sub.2 O.sub.3), magnesium
oxide (MgO), neodymium oxide (Nd.sub.2 O.sub.3), niobium oxide: (NbO,
Nb.sub.2 O.sub.3, and NbO.sub.2), (Nb.sub.2 O.sub.5), plutonium oxide:
(PuO, Pu.sub.2 O.sub.3, and PuO.sub.2), praseodymium oxide: (PrO.sub.2,
Pr.sub.6 O.sub.11, and Pr.sub.2 O.sub.3), promethium oxide (Pm.sub.2
O.sub.3), samarium oxide (SmO and Sm.sub.2 O.sub.3), scandium oxide
(Sc.sub.2 O.sub.3), silicon dioxide (SiO.sub.2), strontium oxide (SrO),
tantalum oxide (Ta.sub.2 O.sub.5), terbium oxide (Tb.sub.2 O.sub.3 and
Tb.sub.4 O.sub.7), thorium oxide (ThO.sub.2), thulium oxide (Tm.sub.2
O.sub.3), titanium oxide: (TiO, Ti.sub.2 O.sub.3, Ti.sub.3 O.sub.5 and
TiO.sub.2), iranium oxide (UP.sub.2, U.sub.3 O.sub.8 and UO.sub.3),
vanadium oxide (VO, V.sub.2 O.sub.3, VO.sub.2 and V.sub.2 O.sub.5),
ytterbium oxide (Yb.sub.2 O.sub.3), yttrium oxide (Y.sub.2 O.sub.3), and
zirconium oxide (ZrO.sub.2). Useful ceramic materials also include boron
carbide, zirconium carbide, beryllium carbide, aluminum beride, aluminum
carbide, boron carbide, titanium carbide, titanium diboride, iron carbide,
iron nitride, barium titanate, aluminum nitride, titanium niobate, boron
carbide, silicon boride, barium titanate, silicon nitride, calcium
titanate, tantalum carbide, graphites, tungsten; the ceramic alloys which
include cordierite/MAS, lead zirconate titanate/PLZT, alumina-titanium
carbide, alumina-zirconia, zirconia-cordierite/ZrMAS; the fiber reinforced
ceramics and ceramic alloys; and glassy ceramics.
Useful materials for fabrication of planar bodies 24 and 26 include metals
such as nickel, manganese, tungsten, magnesium, titanium, aluminum and
steel plate. Illustrative of useful steels are carbon steels which include
mild steels of grades AISI 1005 to AISI 1030, medium-carbon steels of
grades AISI 1030 to AISI 1055, high-carbon steels of the grades AISI 1060
to AISI 1095, free-machining steels, low-temperature carbon steels, rail
steel, and superplastic steels; high-speed steels such as tungsten steels,
molybdenum steels, chromium steels, vanadium steels, and cobalt steels;
hot-die steels; low-alloy steels; low-exapnsion alloys; mold-steel;
nitriding steels for example those composed of low-and medium-carbon
steels in combination with chromium and aluminum, or nickel, chromium and
aluminum; silicon steel such as transformer steel and silicon-manganese
steel; ultrahigh-strength steels such as medium-carbon low alloy steels,
chromium-molybdenum steel, chromium-nickel-molybdenum steel,
iron-chromium-molybdenum-cobalt steel, quenched-and-tempered steels,
cold-worked high-carbon steel; and stainless steels such as iron-chromium
alloys austenitic steels, and chromium-nickel austenitic stainless steels,
and chromium-manganese steel. Useful materials also include alloys such a
manganese alloys, such as manganes aluminum alloy, manganese bronze alloy;
nickel alloys such as, nickel bronze, nickel cast iron alloy
nickel-chromium alloys, nickel-chromium steel alloys, nickel copper
alloys, nickel-molybdenum iron alloys, nickel-molybdenum steel alloys,
nickel-silver alloys, nickel-steel alloys;
iron-chromium-molybdenum-cobalt-steel alloys; magnesium alloys; aluminum
alloys such as those of aluminum alloy 1000 series of commercially pure
aluminum, aluminum-manganese alloys of aluminum alloy 300 series,
aluminum-magnesium-manganese alloys, aluminum-magnesium alloys,
aluminum-copper alloys, aluminum-silicon-magnesium alloys of 6000 series,
aluminum-copper-chromium of 7000 series, aluminum casting alloys; aluminum
brass alloys and aluminum bronze alloys.
As depicted in FIG. 5, 6, 7, 8 and 9 in cross-section, article 10 comprises
a cover layer 14 and backing layer 16, each consisting of a one or more
substrate layers 36, stitched together by horizontal stitches 38 and
vertical stitches (not depicted). Layer 14 is the outer layer which is
exposed to the environment, and layer 16 is the inner layer closest to the
body of the wearer. As depicted in FIG. 4, 5 and 6, article 10 is
comprised of one cover layer 14 which includes substrate four layers
14(a), 14(b), 14(c) and 14(d) and backing layers 16 which includes four
substrate layers 16(a), 16(b), 16(c) and 16(d). However, the number of
layers 14 and 16 and their component substrate layers included in article
10 may vary widely, provided that at least one layer 14 and one layer 16
each having at least one substrate layer are present. In general, the
number of layers in any embodiment will vary depending on the degree of
penetration resistance and flexibility desired. The number layers 14 and
16 is preferably from 1 to about 70, each preferably having from 1 about
50 substrate layers. In the more preferred emobdiments of the invention,
layers 14 and 16 of article 10 include from about 1 to about 20 distinct
layers. The number of layer forming layers 14 and layers 16 are preferably
different. In the most preferred embodiments of the invention, the number
of layers included in layer 14 is kept at a minimum. In these embodiments
of the invention, layer 16 includes a larger number of layers and
functions to catch and hold fragments from the threat and/or portions of
planar bodies 24 or 26 resulting from the impact of the threat from
harming the wearer. In the embodiments the article includes less than
about 10 layers 14, preferably 1 to about 5 layers 14, and from about 10
to about 20 layers 16.
As shown in FIG. 5, substrate layers 14(a), 14(b), 14(c) and 14(d) of cover
layer 14, and substrate layers 16(a), 16(b), 16(c) and 16(d) of backing
layers 16 secured together by horizontal securing means and vertical
securing means (not depicted). In the illustrative embodiments of the
invention depicted in the figures, securing means is stitching; however,
any conventional securing means may be used including but not limited to
bolts, rivets, adhesive, staples, stitches, and the like. While in the
embodiment of the figures all substrate layers of cover layer and of
backing layer 14 or 16 are secured together, it is contemplated that the
number of layers 14 or 16 secured together may be as few as two, or any
number of layers 14 or 16 in article 10 in any combination. In the
preferred embodiments of the invention where the number of layers 14 or 16
is more than about 20, all the layers are not secured together. In these
embodiments, from about 2 to about 20 layers, preferably from 2 to about
12 layers, more preferably from about 2 to about 10 layers and most
preferably from about 2 to about 8 of layers 14 and or layers 16 are
secured together forming a plurality of packets (not depicted).
Substrate layers of cover layer 14 and backing layer 16 may also be secured
together by lamination or an adhesive, or a combination of lamination and
adhesive and stitching. In the preferred embodiments of the invention
depicted in FIG. 3, stitches are utilized to secure substrate layers of
cover layer 14 and backing layer 16. The type of stitching and stitching
methods employed may vary widely and include those described herein above
for use in stitching layers 28 and 30 to form unfilled regions 22. Useful
threads and fibers may vary widely and may be selected from those used to
stitch layers 28 and 30. However, the thread or fiber used in stitching
substrate layers of cover layer 14 and of backing layer 16 is preferably
an aramid fiber or thread (as for example Kevlar.RTM. 29, 49, 129 and 149
aramid fibers), an extended chain polyethylene thread or fiber (as for
example Spectra.RTM. 900 and Spectra.RTM. 1000 polyethylene fibers) or a
mixture thereof.
Materials used in the fabrication of cover layer 14 and backing layer 16
may vary widely, the only requirement is that it is flexible as defined
above. For example, cover layer 14 and backing layer 16 may be a flexible
polymeric or elastomeric film formed from a thermoplastic or elastomeric
resin as described above. Still other useful materials for the fabrication
of layers 14 and 16 are networks of fibers as for example those described
for use in the fabrication of layers 28 and 30 preferably aramid fibers,
such as Kevlar.RTM. 29, 49, 129 and 149 polyethylene fibers such as
Spectra.RTM. 900 and Spectra.RTM. 1000 polyethylene fibers and
combinations thereof. Illustrative of fibrous networks are woven and
nonwoven fabrics either alone or a network of such fibers dispersed in a
matrix of one of more polymeric materials such as one or more
thermoplastic resins one or more thermosetting resins or a combination
thereof. Such fibrous networks are described hereinabove in the
description of materials used to form the fibers of layers 28 and 30. In
one preferred embodiment of the invention, layers 14 and 16 are formed
from fibers which are dispersed in a continuous phase of a matrix material
which preferably substantially coats each filament contained in the fiber.
The manner in which the filaments are dispersed may vary widely. The
filaments may be aligned in a substantially parallel, unidirectional
fashion, or filaments may by aligned in a multidirectional fashion with
filaments at varying angles with each other. In the preferred embodiments
of this invention, filaments in each layer are aligned in a substantially
parallel, unidirectional fashion such as in a prepreg, pultruded sheet and
the like. One such suitable arrangement is where the polymeric layer
comprises a plurality of layers or laminates in which the coated filaments
are arranged in a sheet-like array and aligned parallel to one another
along a common filament direction. Successive layers of such coated,
uni-directional filaments can be rotated with respect to the previous
layer to form a relatively flexible composite. An example of such laminate
structures are composites with the second, third, fourth and fifth layers
rotated +45.degree., -45.degree., 90.degree. and 0.degree., with respect
to the first layer, but not necessarily in that order. Other examples
include composites with 0.degree./90.degree. layout of yarn or filaments.
Techniques for fabricating these laminated structures are described in
greater detail in U.S. Pat. Nos. 4,916,000; 4,623,574; 4,748,064;
4,457,985 and 4,403,012.
The articles of this invention may be fabricated through use of
conventional techniques. For example, bodies 24 may be sewn to a layer
using conventional sewing techniques, preferably at one or more points of
body 24, more preferably a distance from the edge of a body 24. By sewing
a distance from the edge of body 16 flexibility is enhanced. To prevent
extensive disalignment between various layers, adjacent layers can be
stitched together. The thread used to stitch bodies 24 to substrate layers
14 can vary widely, but is preferably a relatively high modulus (equal to
or greater than about 200 grams/denier) and a relatively high tenacity
(equal to or greater than about 15 grams/denier) fiber. All tensile
properties are evaluated by pulling a 10 in. (25.4 cm) fiber length
clamped in barrel clamps at 10 in/min (25.4 cm/min) on an Instron Tensile
Tester. In the preferred embodiments of the invention, the modulus of the
fiber is from about 400 to about 3000 grams/denier and the tenacity is
from about 20 to about 50 grams/denier, more preferably the modulus is
from about 1000 to about 3000 grams/denier and the tenacity is from about
25 to about 50 grams/denier; and most preferably the modulus is from about
1500 to 3000 grams/denier and the tenacity is from about 30 to about 50
grams/denier. Useful threads and fibers may vary widely and include those
described herein below in the discussion of fiber for use in the
fabrication of layers 28 and 30. However, the thread or fiber used in
stitching means is preferably an aramid fiber or thread (as for example
Kevlar 29, 49, 129 and 141 aramid fiber), an extended chain polyethylene
thread or fiber (as for example Spectra 900 fiber and Spectra 1000
polyethylene fiber) or a mixture thereof.
A further embodiments of this invention is depicted in FIG. 10. This
embodiment comprises an cover layer 32 which is exposed to the
environment, and a backing layer 34 which is closest to the body of the
wearer. This embodiment of the invention comprises two layers 36. Each
layer 36 comprises a plurality of composite planar bodies 40 on a surface
of a flexible layer 38. Layer 38 can be formed from the same materials
used to form layers 28 and 30 of article 10 of FIGS. 5 to 9, and planar
bodies 40 may be formed from the same materials as used to form planar
bodies 24 and 26 of article 10 of FIGS. 5 to 9. Planar bodies 40 are
affixed to layer 38 by some suitable method, such as stitches, adhesives,
lamination or a combination thereof (not depicted) to form a pattern of
covered areas 42 and uncovered areas 44. As shown in FIG. 10, the
plurality of planar bodies 40 are positioned on the surfaces of the two
layers 38 such that the covered areas 42 on one layer 38 are in alignment
with the uncovered areas 44 on the adjacent layer 38. In the preferred
embodiments of the invention depicted in FIG. 10, each planar body 40 is
uniformly larger than its corresponding uncovered area 44, such that
planar bodies 40 adjacent to an uncovered area 44 partially overlap with
the corresponding planar bodies 40 of the adjacent composite layer 36 by
some portion 46. The degree of overlap may vary widely, but in general is
such that preferably about 100 area % of the uncovered areas 44 of layer
38 is covered by its corresponding planar body 40 of another layer 38.
FIG. 11 depicts a variant of the embodiment of FIGS. 5, 6 and 7 in which
corresponding parts are referred to by like numerals. The embodiments of
FIG 11 differs from that of the preceeding figures in that planar bodies
24 and 26 are sandwiched between layers 28 and 30.
The composites of this invention can be used for conventional purposes in
the construction of articles of manufacture where flexibility is required
and areal coverage by rigid portions are required to provide some
desirable feature but where such portions are not flexible enough to be
used as a continuous sheet. Such applications include use of the
composites in the fabrication of articles of manufacture for control of
transmission, absorption, reflection and deflection of electromagnetic
radiation (i.e. radio, infrared, visible, UV, X-ray, etc), accoustical
energy, flames, fluids (i.e. gases and liquids) and solids. Other uses of
the composite of this invention include the fabrication of flexible
insulating articles of manufacture such as blankets, clothing, sleeping
bags, tarps, tents, personal floation gear and the like; the fabrication
of backing material for articles of manufacture for reduction of blunt
trauma from threats such as bullets, baseballs, hockey pucks, and the
like; the fabrication of vehicle paneling; the fabrication of protective
apparel and equipment for protection against wild or domestic animals, for
protection of motorcyclists, and for protection of personnel working with
dangerous equipment (i.e. meat cutter, timber cutters, etc), or engaging
in other activities with protection tailored to specific needs; the
fabrication of blankets for furniture moving; the fabrication of wet suits
for scuba divers; the fabrication of bomb blankets; and the like. Still
other applications include use to accessorize clothing, for example,
changing the visibility of the wearer.
In the preferred embodiments of this invention, the composites can be used
in the fabrication of penetration resistant articles and the like using
conventional methods. Such penetration resistant articles include bullet
or puncture proof vests, meat cutter aprons, protective gloves, curtains,
wall panels, canopies, boots, tents, fishing gear and the like.
The composites of this invention are particularly useful in the fabrication
of "bulletproof" vests or ballistic resistant articles such as
"bulletproof" lining for example, or a raincoat because of the flexibility
of the article and its enhanced ballistic resistance. In ballistic
studies, the specific weight of the shells and plates can be expressed in
terms of the areal density (ADT). This areal density corresponds to the
weight per unit area of the ballistic resistant armor. In the case of
filament reinforced composites, the ballistic resistance of which depends
mostly on filaments, another useful weight characteristic is the filament
areal density of the composite. This term corresponds to the weight of the
filament reinforcement per unit area of the composite (AD).
The following examples are presented to provide a more complete
understanding of the invention and are not to be construed as limitations
thereon.
EXAMPLE 1
Several composites of this invention were fabricated and evaluated for
flexibility and for noise reduction. The fabrication and evaluation
procedures employed are as follows.
I. Composite Fabrication
A. Composite 1
Linearly truncated equilateral aluminum triangles (0.05" (0.127 cm) thick.
(See FIG. 21) were sewn onto opposite sides of five fabric layers of
ballistic nylon fabric (style 000-26042 from Burlington Industries having
33.times.33 yarns/in (13.times.13 yarns/cm))having an areal density of
0.27 Kg/m.sup.2 in the pattern shown in FIG. 22. Alternatively, a
non-linearly truncated aluminum plate can be used which minimizes the
uncovered area of the fabric layer. (See FIG. 23) Grid size of the
equilateral triangular pattern of the fabric had a side length of 1.5
inches (3.8 cm). Three pairs of sewing holes, inset 0.5 inches (1.27 cm)
from the truncated apexes and 0.05 inches (0.127 cm) in diameter, were
used to sew the aluminum triangles onto the five fabric layers using 580
denier SPECTRA.RTM. 1000 sewing thread.
B. Composite 2
This composite was identical to composite 1 except that 2.3 in. (5.8 cm)
triangular bodies were used.
C. Composite 3 and Composite 4
These composites were identical to composite 1 except that hexagons (1.5
in. (3.8 cm) side length) were sewn on the top impact side of the fabric
layers with three points of attachment and triangles were sewn on the
bottom side in the arrangement of FIG. 24; and in composite 4, the
hexagons were sewn on the bottom side with three points of attachment and
the triangles were sewn on the impact side with three points of attachment
also in the arrangement of FIG. 24.
D. Composites 5 and 6
These composites were identical to composites 3 and 4 respectively, except
that the hexagons were attached at six points of attachment near each apex
of the hexagon.
E. Comparative Composites 1 and 2
These composites were the same as composite 1, except that all triangles
were sewn on the same side of the fabric layer as depicted in FIG. 25. In
Comparative Composite 1, triangles were sewn on the top impact side and in
Comparative Composite 2, triangles were sewn on the bottom side.
F. Composite 7
This composite was identical to composites 3 and 4 in materials of
construction and the use of hexagonal and triangular shaped bodies, except
that the hexagons were sewn between two layers of ballistic nylon fabric
using 580 denier SPECTRA.RTM. 1000 thread and the triangles were sewn to
both sides of the two layered hexagon construction as depicted in FIG. 26.
G. Composite 8
Aluminum hexagons having side length of 1.5 inches (3.8 cm) and thickness
of 0.05 inches (0.27 cm), were placed on a cotton fabric in the pattern
shown in FIGS. 26 and 27. A sheet of fabric adhesive (Wonder-Pellon Under
Transfer Web, a product of Freudenberg Nonwovens) and an identical cotton
fabric layer were placed over the metal plates. The top and bottom fabrics
were laminated together in the triangular areas not occupied by metal
plates with heat and pressure using a conventional clothes iron and
appropriately sized aluminum triangles as temporary backing during the
ironing operation.
H. Composite 9
Aluminum hexagons having side lengths of 1.5 inches (3.8 cm) and thickness
of 0.05 inches (0.127 cm) were placed on a cotton fabric in the pattern
shown in FIG. 27. A sheet of fabric adhesive (Wonder-Pellon Under Transfer
Web, a product of Freudenberg Nonwovens) and an identical cotton fabric
layer were placed over the metal plates. The top and bottom fabrics were
laminated together in the triangular areas not occupied by metal plates
with heat and pressure using a conventional clothes iron and appropriately
sized aluminum triangles as backing as depicted in FIG. 28 (b).
Two similar panels were constructed which incorporated aluminum triangles
in the arrangement shown in FIGS. 26(b) and 26(c) between a top and bottom
fabric layers were laminated together in the hexagonal areas not occupied
by metal plates in an arrangement similar to FIG. 27(b). The aluminum
equilateral triangles had side lengths of 1.9 inches (4.83 cm) before
truncation and 1.4 (3.56 cm) inches after linear truncation.
The three panels, one with isolated hexagons and two with isolated
triangles, were placed together with the panel containing the hexagons in
the central position and sewn around three sides of the perimeter to
create a panel 14 inches (35.6 cm) square which provided complete areal
coverage by the metal plates.
I. Evaluation of Composites
A. Flexibility
1. Drape Test 1
Composites were evaluated in Drape Test 1. The results are set forth in the
following Table I. The results are expressed as the ratio of the extent to
which end of the composite drops from the plane of the support (H) to the
length of the composite extending from the support (L), or H/L.
TABLE I
______________________________________
Flexibility of Composites Drape Test 1
EXP. H/L
NO. SAMPLE 0.degree.
30.degree.
45.degree.
60.degree.
90.degree.
______________________________________
1 Comp 0.91 0.90 0.91 0.93 0.86
Composite 1
2 Comp 0.80 0.75 0.77 0.84 0.70
Composite 2
3 Composite 1
0.93 0.86 0.85 0.94 0.83
4 Composite 2
0.92 0.79 0.75 0.96 0.76
5 Composite 3
0.92 0.90 0.85 0.97 0.93
6 Composite 4
0.91 0.79 0.77 0.93 0.89
7 Composite 5
0.93 0.83 0.81 0.96 0.73
8 Composite 6
0.90 0.81 0.79 0.93 0.72
9 Composite 7
0.97 0.72 0.83 0.99 0.87
10 Composite 8
1.0 0.68 0.81 0.99 0.88
______________________________________
2. Drape Test 2
The composites were evaluated in Drape Test 2. The results are set forth in
the following Table II.
TABLE II
______________________________________
Ex. No. Sample No H/L Ratio
______________________________________
1 Comp Composite 1
0.33
2 Comp Composite 2
0.23
3 Composite 1 0.48
4 Composite 2 0.59
5 Composite 3 0.34
6 Composite 4 0.45
7 composite 5 0.41
8 Composite 6 0.40
______________________________________
A series of experiments were carried out to estimate the level of noise
generation by certain embodiments described in EXAMPLE 1. In these
experiments, the level of noise generation was determined subjectively by
shaking the composites and listening to the noise generated. For
comparison purposes, the level of noise generated by an all fabric
standard PASGT vest was evaluated as a control. The results are set forth
in the following Table III.
In the Table, the relative performance of the composites was rated as
follows:
a) "1" indicates that no or substantially no noise was generated which is
substantially identical to the standard PASGT vest control;
b) "2" indicates that a small amount of noise was generated as compared to
the standard PASGT vest control;
c) "3" indicates that a moderate amount of noise was generated as compared
to the standard PASGT vest control; and
d) "4" indicates that a large amount of noise generated as compared to the
standard PASGT vest control.
TABLE III
______________________________________
Level of Noise
Exp. No. Composite Generated
______________________________________
1 Control 1
2 Composite 9 1
3 Composite 1 2
4 Comp. Composite 1
3
5 Comp. Composite 3
4
______________________________________
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