Note: Descriptions are shown in the official language in which they were submitted.
W O 91/07632 PC-r/~S90/064~3
BALLISTIC RESISTANT COMPOSITE ARMOR
~ACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to ballistic resistant
composite articles. More particularly, this invention
relates to such articles having improved ballistic
protection and having improved multiple-hit capability.
2. ~Lior Art
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 matri~ material.
US Patent Nos. 4,623,574 and 4,748,064 disclose a
simple composite structure e~hibits outstanding ballistic
protection as compared to simple composites utilizing
rigid matrices, the results of which are disclosed in the
patents. Particularly effective are weight polyethylene
and polypropylene such as disclosed in US Patent No.
4,413,110.
US Patent Nos. 4,737,402 and 4,613,535 disclose
comple~ rigid composite articles having improved impact
resistance which comprise a network of hiqh strength
fibers such as the ultra-high molecular weight
polyethylene and polypropylene disclosed in US Patent No.
35 4,413,110 embedded in an elastomeric matri~ material and
at least one additional rigid layer on a major surface of
the fibers in the matri~. It is disclosed that the
., ' ~ '.
~0 91/07632 ~'Cl/~S90/064~3
~ , r . ;.
-- 2
composites have improved resistance to environmental
hazards, improved impact resistance and are une~pectedly
effective as ballistic resistant articles such as armor.
US Patent No. 4,836,084 discloses an armor plate
composite composed of four main components, a ceramic
impact layer for blunting the tip of a projectile, a
sub-layer laminate of metal sheets alternating with
fabrics impregnated with a viscoelastic synthetic material
for absorbing the kinetic energy of the projectile by
plastic deformation and a backing layer consisting of a
pack of impregnated fabrics. It is disclosed that the
optimum combination of the four main components gives a
high degree of protection at a limited weight per unit of
surface area.
Ballistic resistant armor made of ceramic tiles
connected to a metal substrate e~hibit certain properties
which substantially reduces the multiple hit capability of
the armor. On impact of the projectile, substantial
amounts of vibrational energy is produced in addition to
the kinetic energy of the impact. This vibrational energy
can be transmitted as noise and shock, or can be
transmitted to vibration sensitive areas of the armor such
as to the ceramic impact layer resulting in a shattering
and/or loosing of tiles.
SUMMARY OF THE INVENTION
This invention relates to a multilayer comple~
ballistic armor comprising:
(a) a hard impact layer comprised of one or more
ceramic bodies bound to a surface of a backing layer;
(b) peripheral hard impact layer retaining means
comprising an elastic material positioned about the outer
periphery of said hard impact layer and in contact
therewith; and
(c) peripheral ceramic body retaining means
comprising an interconnected network comprising an elastic
: . ~
.
,
. . .
~091/07632 PCT/~.~90/06~3
~ 7.
-- 3 --
material positioned about the periphery of each of said
ceramic bodies comprising said hard impact layer.
Several advantages flow from this invention. For
example, through use of the peripheral hard impact layer
retaining means and the peripheral ceramic body retaining
means, the concentrated impact energy of the projectile
can be absorbed without fracture or loss of ceramic bodies
surrounding the ceramic body at the point of impact and
can be transmitted and distributed throughout the entire
comple~ ballistic armor. Furthermore, through use of this
invention the performance of the tiles at the edges of the
armor adjacent to peripheral impact layer retaining means
and the performance of the portions of individual tiles
adjacent to the peripheral ceramic retaining means which
is relatively weak are as good as or substantially as good
as the performance at the center of the armour and at the
center of individual tiles.
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 l is a view in cross-section and in side
elevation of an armor plate according to this invention
showing its essential elements of a ceramic impact layer,
a peripheral hard impact layer retaining means, a
peripheral ceramic body retaining means and a backing
layer;
FIG 2 is a view in cross-section and side elevation
of a modified embodiment of this invention depicted in
Fig. 2 which includes a cover layer and a release layer.
FIG 3 is a view in cross-section and side elevation
of a modified embodiment of this invention depicted in FIG
2 which includes vibration isolating layer.
"
- ,: , ,
.
~0 91/07632 PCr/l S90/064~3
" ""
-- 4
DETAILED DESCRIPTIQN OF THE I~VEN~IQ~
The present invention will be better understood b-
~those of skill in the art by reference to the above
5 figures. Referring to FIG 1, the numeral 10 indicates a
ballistic resistant article 10. Article 10, as shown in
FIG 1, comprises four main components; a ceramic impact
layer 12, peripheral hard impact layer retaining means 14,
peripheral ceramic body retaining means 16, and a backing
layer 18.
A ceramic impact layer 12 is escellently suitable for
blunting the tip of the projectile, particularly because
the ceramic material forming layer 12 will retain its
hardness and strength despite the high increase in
temperature that will occur in the region struck by a
projectile~ Ceramic impact layer 12 comprises one or more
ceramic bodies 20~ In the preferred embodiments of the
invention, layer 12 comprises a plurality of ceramic
bodies 20, in the more preferred embodiments of the
invention layer 12 comprises at least about four ceramic
bodies 20 and in the most preferred embodiments , layer 12
comprises at least about nine ceramic bodies 20 with those
embodiments in which the number of ceramic bodies 20 in
layer 12 is at least about sisteen being the embodiment of
choice.
Ceramic body 20 is formed of a ceramic material. As
used herein, a ~ceramic material~ is an inorganic material
having a hardness of at least about Brihell hardness of 25
or Mohs hardness of 2. Useful ceramic materials may vary
widely and include those materials normally used in the
fabrication of ceramic armor which function to partially
deform the initial impact surface of a projectile or cause
the projectile to shatter. Illustrative of such metal and
non-metal ceramic materials are those described in C.F.
Liable, Ballistic Materials and Penetration Mechanics,
Chapters 5-7 (1980) and include single osides such as
aluminum oside (A12O3), barium oside (BaO), beryllium
oside (BeO), calcium oside (CaO) cerium osides (Ce2O3
~,
., , , ." . ,
,, , ,, ",,, ,, ," ; " ":, .. ..
,
.
U'O 91/n/632 Pcr/~sso/06~3
-- 5
and CeO2), chromium o~ide (Cr203), dysprosium o~ide
(Dy2o3)~ erbium o~ide (Er203), europium o~ides
23' EU24 and EU1621)' gadolinium
oxide (Gd203), hafnium o~ide (HfO2), holmium oxide
(Ho203), lanthanum o~ide (La203), lutetium oside
(Lu203), magnesium 02ide (MgO), neodymium o~ide
(Nd203), niobium o~ides (NbO, Nb203, NbO2 and
Nb205), plutonium osides (PuO, Pu203 and Pu02),
praseodymium osides (PrO2, Pr6011 and Pr203),
promethium oside (Pm203), samarium osides (SmO),
(Sm203), scandium o~ide (Sc203), silicon dioside
(SiO2), strontium oside (SrO), tantalum oside
(Ta205), yerbium o~ides (Tb203 and Tb407),
thorium oxide (ThO2), thulium oside (Tm203),
titanium osides (TiO, Ti203, Ti305 and TiO2),
uranium o~ides (Uo2, U308 and U03), vanadium
osides (VO, V203, V02 and V205), ytterbium oside
(Yb203), yttrium oside (Y203), and zirconium oside
(ZrO2). Useful ceramic materials also include boron
carbide, zirconium carbide, beryllium carbide, aluminum
beride, aluminum carbide, boron carbide, 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; glassy ceramics; silicon carbide,
aluminum carbide, titanium nitride, boron nitride,
titanium carbide, titanium diboride, iron carbide,
aluminum nitride, iron nitride, barium titanate, titanium
niobate, boron carbide, silicon boride, as well as other
useful materials. Preferred materials for fabrication of
ceramic body 16 in Fig. 2 are aluminum oside, and metal
and non metal nitride~, borides and carbides. The most
preferred material for fabrication of ceramic body 18 is
aluminum oside and titanium.diboride.
The structure of ceramic body 20 can vary widely
depending on the use of the article. For esample, ceramic
.
;, , '
. . ~ , :
~091/07632 PCTt~S90/064;3
-- 6
body 20 can be a unitary structure composed of one ceramic
material or of multilayer construction of the same
material or of different ceramic materials.
While in the figures ceramic body 20 is depicted as a
cubular solid, the shape of ceramic body 20 can vary
widely depending on the use of the article. For e~ample,
ceramic body 20 can be an irregularly or a regularly
shaped body. Illustrative of a useful ceramic body 20 are
cubular, rectangular, cylindrical, and polygonal (such as
triangular, pentagonal and he~agonal) shaped bodies. In
the most preferred embodiments of this invention, ceramic
body 20 is of cubular, rectangular or cylindrical cross-
section.
The size (width and height) of ceramic body 20 can
also vary widely depending on the use of article 10. For
e~ample, in those instances where article 10 is intended
for use in the fabrication of light ballistic resistant
composites for use against light armaments, ceramic body
20 is generally smaller; conversely where article 10 is
intended for use in the fabrication of heavy ballistic
resistant composites for use against heavy armaments then
ceramic body 20 is generally larger.
The embodiment 10 of FIG 1 includes peripheral -
ceramic body retaining means 20 between individual ceramic
bodies 16 and a peripheral hard impact layer retaining
means 14. Peripheral ceramic body retaining means 16 and
peripheral hard impact layer retaining means 14 minimizes
or reduces the differeneces in ballistic resistant
performance of ceramic impact layer 12 at the edges of
ceramic layer 12 and ceramic bodies 20, and at the seams
formed by adjacent ceramic bodies 20, which because of the
segmented nature of-ceramic layer 12 normally tends to be
relatively weak areas, and at or about the center of
ceramic bodies 20 and.ceramic layer 12 which tends to be
relatively strong areas. The relatively performance of
the armor of this invention can be e~pressed as the
efficiency of penetration resistance.
" ;, ,,
" , ,, ! ' ' . '
", ' ' ' ' ' ' ',,
' " ' '. ~
091/0~63~ PCr/1_590/064~3
-- 7
The specific energy absorption ~SEA) is employed to
determine the difference in the penetration resistance
performance (or the ~ efficiency of penetration
resistance) at the weak areas (such as seams, edge, and
corner) as compared to that for the cente of tile (strong
area). The specific energy absorbed during a ballistic
impact is calculated based on the areal density (AD) using
the following equation:
SEA (Jm2/kg) , 1/2 [mV2/AD]
where
m is mass of projectile;
V is velocity of projectile which is statistically at
the borderline of complete penetration (i.e. the
projectile velocity which has a 50% probability of
penetreating the target) and AD is the areal density and
is the weight of armor per unit area kg/m2.
The % efficiency can be calculated using the
following equation:
% efficiency . 100% ~ [1 - DSEA/SEAc]
where
SEAc is the specific energy absorption at about the
center of ceramic body 20; and
DSEA is the difference in specific energy absorption
and is equal to SEA - specific energy absorption at the
weak areas.
In the preferred embodiments of the invention, the %
efficiency at about the seam between adjacent ceramic
bodies 20 is at leaSte about 80% of the % efficiency at or
about the center of at least one of said adjacent ceramic
bodies 20, the % efficiency at or about an edge of a
3S ceramic body 20 is at least 70% of the % efficiency at or
about the center of said ceramic body 20 and the %
efficiency at or about a corner of a ceramic body 20 is at
least about 60% of the % efficiency at or about the center
" "
.
',: ;, '
U091/076~ PCT/~'S90/06453
~ :
-- 8
of said ceramic body 20. In the more preferred
embodiments of the invention, the % efficiency at or about
a seam between adjacent ceramic bodies 20, at or about an
edge of a ceramic body 20 and at or about a corner of a
ceramic body 20 is at least about 95% of the ~ efficiency
at or about the center of ceramic body 20, and in the most
preferred embodiments of the invention, the ~ efficiency
at or about a seam between adjacent ceramic bodies 20, at
or about an edge of ceramic body 20 and at or about a
corner of ceramic body 20 is at least about 99~ of the 5
efficiency at or about the center of ceramic body 20.
Peripheral ceramic body retaining means 16 also allows the
ma~imum loading of ceramic bodies 20 in segmented ceramic
impact layer 12, provides optimized spacing between
adjacent ceramic bodies 20; retains un-impacted ceramic
bodies 20 in place upon severe impact deformation; and
transmits and distributes the impact shock to the entire
composite upon impact.
Peripheral ceramic body retaining means 16 and hard
impact layer retaining means 14 are composed of an "elastic
material", which may vary widely and may be metallic, semi-
metallic material, an organic material and/or an inorganic
material. As used herein an "elastic material~ is a
material which is herently rigid, capable of free standing
25 without collapsing.
Illustrative of such materials are those described in
G.S. Brady and H.R. Clauser, Materials Handbook, 12th
edition (1986). Illustrative of the preferred materials
for use of backing material described earlier are suitable
for use as materials for peripheral ceramic body retaining
means 16 and peripheral hard impact layer retaining means
14.
Useful materials include high modulus thermoplastic
polymeric materials such as polyamides as for e~ample
aramids, nylon 6 and nylon 66, and the like; polyesters
such as poly(ethylene terephthalate), poly(butylene
terephthalate), and the like; acetalo, polysulfones;
polyethersulphones; polyacrylates, acylonitrile/butadine/
.
.
.
~09l/0763' PCT/~S90/064~3
~ .. ,' ~, -` ,`
styrene copolymers, poly(amideimide), poly(etherethar
ketones), polycarbonates; polyphenylenesulfides;
polysulfides, vinylesters, polyurethanes, polyphenylene
oxides; polyestercarbonates; polyesterimides and the like;
thermosetting resins such as epo~y resins, phenolic
resins, saturated polyesters, silicones, polyurethanes,
alkyd resins, melamine and urea resins and the li~e;
polymer alloys and blends of thermoplastics polymers
and/or thermosetting resins described above; and
interpenetrating polymer networks such as those of
polycyanate ester of a polyol such as the dicyanoester
bisphenol and a thermoplastic such as polysulfone. The
material may be reinforced by high strength filaments such
as aramid filament, Spectra~ e~tended chain polyethylene
filaments, boron filament, poly glass filaments, ceramic
filaments, carbon and graphite filament, and the like.
Useful preferred materials for fabrication of
peripheral ceramic body retaining means 16 and peripheral
hard impact layer retaining means 14 also include metals
such as nickel, manganese, tungsten, magnesium, titanium,
aluminum and steel. Useful and preferred steels include
carbon steels such as 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, molybolenum steels,
chromium steels, vanadium steels, and colbat steels;
hot-die steels; low-alloy steels; low-e~pansion alloys;
mold-steel; nitriding steels such as low-and medium-carbon
steels with combinations of chromium and aluminum, or
nickel, chromium, and aluminum; silicon steel such as
transformer steel and silicon-manganese steel;
ultrahigh-strength st~eels such as medium-carbon low alloy
steels, chrominum-molydenum steel, chromium-nickel-
molybdenum steel, iron-chromium-molydenum-cobalt steel,
quenched-and-tempered steels, and cold-worked high-carbon
steel; stainless steels such as iron-chromium alloy
.. i
,
,, ~ ,
.
WO91/07632 PCT/~S90/0~;3
~ .;t
-- 10 --
austensitic steels, chromium-nickel austensitic stainless
steels, and chromium-manganese steel. Useful and
preferred materials also include alloys such as manganese
alloys, manganese aluminum alloy, manganese bronze alloy;
nickel alloys, nickel bronze alloy, nickel cast iron
alloy, nickel-chromium alloys, nickel-chromium steel
alloy, nickel copper alloy, nickel-molyldenium iron alloy,
nickel-molybdenum steel alloy, nickel-silver alloy,
nickel-steel alloy; iron-chromium-molybdenum-cobalt steel
alloy; magnesium alloys; aluminum alloys such as 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
alloy, and aluminum bronze.
The ceramic bodies 20 are attached to backing layer
18 which supports hard impact layer 12 peripheral hard
impact layer retaining means 14 and peripheral ceramic
body retaining means 16, and which provides additional
ballistic protection. The amount of a surface of backing
layer 18 covered by ceramic bodies 20 may vary widely. In
general, the greater the area percent of surface covered
or surface loaded, the more effective the protection, and
conversely, the lower the area percent of surface covered
the less effective the protection. In the preferred
embodiments of the invention, the area percent of the
surface of backing layer 18 covered by ceramic bodies 20
is equal to or greater than about 95 area percent based on
the total area of backing layer 18, and in the more
preferred embodiments of the invention the area percent
covered is equal to or greater than about 97 area percent
on the aforementioned.basis. Amongst the more preferred
embodiments of the invention, most preferred are those
embodiments in which the area percent of the surface of
backing layer 18 covered by ceramic bodies 20 is equal to
; ,................. . . . . .
' ' ' ' , '
', ' ' - ,:, ': . , '
. : .
WO 91/07632 pcr/1 590/1)64~3
-- 11 --
or greater than about 98 or 99 area percent based on the
total surface area of backing layer 18.
Means for attaching ceramic bodies 20 to backing
layer 18 may vary widely and may include any means
normally used on the art to provide this function.
Illustrative of useful attaching means are adhesive such
as those described in Liable, Chapter 6, supra, bolts,
screws, mechanical interlocks adhesives such as metal and
non-metal adhesives, organic adhesives and the like. In
the preferred embodiments of this invention attaching
means is selected from the group consisting of fle~ible
adhesive bonding agents. Such fle~ible bonding agents
provide several useful functions. For e~ample, such
agents enhance structural performance such that the
compsite is capable of withstanding severe impact loads,
and they enhance the retention of se~mented tiles which
are not at the point of impact and the retention of
spall/particles created by the shattering of tiles on
impact. Su^h adhesive also enhance the conversion of
absorbed energy into heat. As used herein, a ~fle~ible
adhesive" is a polymeric adhesive which e~hibits a Shore A
Hardness of from about 15 to 120.
In the preferred embodiments of the invention, the
adhesive material is a low modulus, elastomeric material
25 which has a tensile modulus, measured at about 23 C, of
less than about 7,000 psi (41,300 kpa). Preferably, the
tensile modulus of the elastomeric material is less than
about 5,000 psi (34,500 kpa), more preferably is less than
1,000 psi (5900 kpa) and most preferably is less than
about 500 psi (3450 kpa) to provide even more improved
performance. The glass transition temperature (Tg) of the
elastomeric material (as evidenced by a sudden drop in the
ductility and elasticity of the material) is less than
about 0 C. Preferably, the Tg of the elastomeric material
is less than about -40~C, and more preferably is less than
about -50C. The elastomeric material also has an
elongation to break of at least about 5%. Preferably, the
elongation to break of the elastomeric material is at
W09l/07632 PCT/~S90/064~3
- 12 -
least about 30~. Representative e~amples of suitable
elastomeric materials for use as a flexible adhesive are
those wich have their structures, properties, and
formulation together ~ith cross-linking procedures
summarized in the Encyclopedia of Polymer Science, Vol. 5
in the section Elastomers-Synthetic (John Wiley ~ sons
Inc., 1964) and "Handbook of Adhesives", Van Nostrand
Reinhold Company (1977), 2nd Ed., Edited by Irving
Skeist. Illustrative of such materials are block
copolymers of conjugated dienes such as butadiene and
isoprene, and vinyl aromatic monomers such as styrene,
vinyl toluene and t-butyl styrene; polydienes such ag
polybutadiene and polychloroprene, polyisoprene; natural
rubber; copolymers and polymers of olefins and dienes such
as ethylene-proPylene copolymers, ethylene-propylene-diene
terpolymers and poly(isobutylene-co-isoprene), polysulfide
polymers, polyurethane elastomers, chlorosulfonated
polyethylene; plasticized polyvinylchloride using dioctyl
phthate or other plasticizers well known in the art,
butadiene acrylonitrile elastomers, , polyacrylates such
as poly(acrylic acid), poly(methylcyanoacrylate),
poly(methylacrylate), poly(ethyl acrylate),
poly(propylacrylate) and the like; polyacrylics such as
poly(acrylonitrile), poly(methylacrylonitrile),
pQly(acrylamide), poly(N-isopropylacrylamide) and the
like, polyesters; polyethers; fluoroelastomers;
poly(bismaleimide); flesible eposies; flesible phenolics;
polyurethanes; silicone elastomers; eposy-polyamides;
poly(alkylene osides); polysulfides; flesible polyamides;
unsaturated polyesters; vinyl esters, polyolefins, such as
polybutylene and polyethylene; polyvinyls such as
poly(vinyl farmate), poly(vinylbenzoate), poly(vinyl-
carbazole), poly(vinylmethylketone), poly(vinyl-methyl
ether), polyvinyl acetate, polyvinyl butyral, and
poly(vinyl formal); and polyolefinic elastomers.
Preferred adhesives are polydienes such as ~ -
polybutadiene, polychloroprene and polyisoprene; olefinic
and co-polymers such as ethylene-propylene copolymers,
, ,', . . . .
,, ' . ,, ' ' ' ~,, ',, .. .:
.
.
. - .
~`0'~ ,6~2 PCr/~S9()/~64~3
~:_. J .~.'., -, ~
ethylene-propylene-diene copolymers, isobutylene-isoprene
copoly~ers, and chlorosulfonated polyethylene; natural
rubber; polysulf ides; polyurethane elastomers;
polyacrylates; polyethers; fluoroelastomer; unsaturated
polyesters; vinyl esters; alkyds; fle~ible epo2y; fle~ible
polyamides; epichlorohydrin; poly vinyls; fle~ible,
phenolics; silcone elastomers; thermoplastic elastomers;
copolymers of ehtylene, polyvinyl formal, polyvinyl
butyal; and poly~bis-maleimide). Blends of any
combination of one or more of the above-mentioned adhesive
materials. Most preferred adhesives are polybutadiene,
polyisoprene, natural rubber, ethylene-propylene
copolymers, ethylene-propylene-diene terpolymers,
polysulfides, polyurethane elastomers, chlorosulfonated
lS polyethylene, polychloroprene, poly(isobutylene-co-
isoprene), polyacrylates, polyesters, polyethers,
fluoroelastomers, unsaturated polyesters, vinyl esters,
fle~ible epo~y, flesible nylon, silicone elastomers,
copolymers of ethylene, polyvinyl formal, poly vinyl
butryal. Blends of any combination of one or more of the
above-mentioned adhesive materials.
Backing layer 18 is a rigid layer which functions to
support hard ceramic impact layer 12. The term "rigid" is
used in the present specification and claims is intended
to include structures which are free standing without
collapsing which includes semi-fle~ible and semi-rigid
structures. The material employed in backing layer 18 may
vary widely, and may be a metallic material, a
semi-metallic material, an organic material and/or an
inorganic material. Illustrative of such materials are
those described in G.S. Brady and H.R. Clauser, Ma~Q~ials
Handbook, 12th edition (1986). Backing layer 18 is
comprised of a ballistic resistant material which may vary
widely depending on the uses of article 10, snd offers
additional ballistic protection. Backing layer 18 can
comprise a single layer or can comprise a plurality of
layers of the same material or different materials. In
WO 91/07632 PCr/l S90/06~3
- 14 _
the preferred embodiments of this invention, backing layer
18 comprises one or more rigid layers.
Preferred materials used in the fabrication of
backing layer 18 are those materials preferred for use in
the fabrication of peripheral hard impact layer retaining
means 14 and peripheral ceramic body retaining means 16.
Such preferred materials include metals such as nickel,
manganese, tungsten, magnesium, titanium, aluminum and
steel and alloys such as manganese alloys, nickel alloys,
and aluminum alloys which make optionally in fibrous
reinforcement by inorganic fibers such as silicone
carbide. Such materials also include thermoplastic
polymeric materials such as polycarbonates; polyether
ether, polyamides, polyesters, keton s, polysulfides,
polyethersulfones, polyacrylate, acrylonitrile/butadiene/
styrene copolymers, poly(amideimide), polyphenylene-
sulfides; polyurethanes, polyphenylene o~ides,
polyestercarbonates; polyesterimides, and the like; and
thermoset resins such as epo~y resins, phenolic resins,
vinyl ester resins, modified phenolic resins, unsaturated
polyester, allylic resins, alkyd resins, urethanes and
melamine and urea resins; polymer alloys and blends of
thermoplastics and/or thermosetting resins; and
interpenetrating polymer network such as those of
polycyanatopolyol such as dicyanoester bisphenol A and a
thermoplastic resin such as polysulfone.
In the most preferred embodiments of this invention
backing layer 18 comprises one or more layers at least one -
of which comprises a network of high strength filaments
having a tenacity of at least about 7 grams/denier, a
tensile modulus of at least about 160 grams/denier and an ~-
energy-in-break of at least about 8 joules/gram in a
matris. The fibers in the backing layer 18 may be
arranged in networks having various configurations. For
e~ample, a plurality of filaments can be grouped together
to form a twisted or untwisted yarn bundles in various
alignment. In preferred embodiments of the invention, the
filaments are aligned substantially parallel and
wo gl/07632 PCI/I S90/064~3
- 15 -
unidirectionally to form a unia~ial layer in which a
matri~ material substantially coats the individual
filaments. Two or more of these layers can be used to
form a layer 18 with multiple layers of coated
S undirectional filaments in which each layer is rotated
with respect to its adjacent layers. An e~ample is a with
the second, third, fourth and fifth layers rotated +45 ,
-45 , 90 and 0 with respect to the first layer, but not
necessarily in that order. Other esamples include a layer
12 with a 0 /9o layout of yarn or filaments.
The type of filaments used in the fabrication of
layer 18 may vary widely and can be metallic filaments,
semi-metallic filaments, inorganic filaments and/or
organic filaments. Preferred filaments for use in the
practice of this invention are those having 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-in-break equal to or greater than about 8
joulés/grams. Particularly preferred filaments 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 filaments are equal to or greater than
about 25 g/d, and 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 and the energy-to-break is equal
to or greater than about 40 joules/gram.
Illustrative of useful organic filaments are those
composed of aramids-(aromatic polyamides), such as
poly(m-sylylene adipamide), poly(p-sylylene sebacamide),
poly 2,2,2-trimethylhesamethylene terephthalamide), poly
(piperazine sebacamide), poly (metaphenylene
isophthalamide) (Nomes) and poly (p-phenylene
terephthalamide) (Kevlar); and aliphatic and
cycloaliiphatic polyamides, such as the copolyamide of 30%
.'.' ' , :,
; , , ':
, ,, , , - , - -
~',-
~091/07632 PCT/~S90/064
- 16 -
hezamethylene diammonium isophthalate and 70~
he~amethylene diammonium adipate, the copolyamide of up to
30% bis-(-amidocyclohesyl)methylene, terephthalic acid and
caprolactam, polyhe~amethylene adipamide (nylon 66),
poly(butyrolactam) (nylon 4), poly (9-aminonoanoic acid)
(nylon 9), poly(enantholactam) (nylon 7),
æoly(capryllactam) (nylon 8), polycaprolactam (nylon 6),
poly (p-phenylene terephthalamide), polyhesamethylene
sebacamide ~nylon 6,10), polyaminoundecanamide (nylon 11),
polydodeconolactam (nylon 12), polyhesamethylene
isophthalamide, polyhexamethylene terephthalamide,
polycaproamide, poly(nonamethylene azelamide) (nylon 9,9),
poly(decamethylene azelamide) (nylon 10,9), poly(decam-
ethylene sebacamide) (nylon 10,10), poly[bis-(4-amino-
cyclothesyl) methane 1,10- decanedicarbosamide] (Qiana)
(trans), or combination thereof; and aliphatic, cycloali-
phatic and aromatic polyesters such as poly(l,4-cyclo-
heslidene dimethyl eneterephathalate) cis and trans,
poly(ethylene-l, 5-naphthalate), polytethylene-2~6
naphthalate), poly(l, 4-cyclohesane dimethylene
terephthalate) (trans), poly(decamethylene terephthalate),
poly(ethylene terephthalate), poly(ethylene isophthalate),
poly(ethylene osybenozoate), poly(para-hydrosy benzoate),
poly(dimethylpropiolactione), poly(decamethylene adipate),
25 poly(ethylene succinate) and the like. ~ -'
Also illustrative of other useful organic filaments
for use in the fabrication of backing layer 18 are those
of liquid crystalline polymers such as lyrotropic liquid
crystalline polymers which include polypeptides such as
polyy-benzyl L-glutamate, aromatic polyamides such as
poly(l,4-benzamide), poly(chloro-1,4-phenylene
terephthalamide), poly(l,4-phenylene fumaramide),
poly(chloro-1,4-phenylene fumaramide), poly(4,4~-
benzanilide trans, trans-muconamide), poly(l,4-phenylene
mesaconamide), poly(l,4-phenylene) (trans-1,4-
cyclohe~ylene amide), poly(chloro-1,4-phenylene)
(trans-1,4-cyclohesylene amide), poly(l,4-phenylene
1,4-dimethyl-trans-1.,4-cyclohesylene amide), poly(l,4-
- ' .
,
" , : .,
uosl/n~63 PCT~590/064~3
~ .t
- 17 _
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(l,4-phenylene 4,4~-stilbene
amide), poly(chloro-1,4-phenylene 4,4~-stilbene amide),
poly(l,4-phenylene 4,4'-azobenzene amide), poly(4,4~-
azobenzene 4,4'-azobenzene amide), poly(l,4-phenylene
4,4~-azo~ybenzene amide), poly(4,4~-azobenzene 4,4~-
azo~ybenzene amide), poly(l,4-cyclohesylene 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~l.4-phenylene 4,4'-bibenzo -
amide), poly(l,4-phenylene 4,4'-terephenylene amide),
poly(l,4-phenylene 2,6-naphthal amide), poly(l,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'-dimetho~y-4,4-
biphenylene 4,4'-bibenzo amide), polyosamides such as
those derived from 2,2'dimethyl-4,4'diamino biphenyl and
chloro-1,4-phenylene diamine; polyhydrazides such as poly
chloroterephthalic hydrazide and those derived from
osalic, terephthalic, chloroterephtalic, and 2,5-pyridine
diccronylic acids, poly(terephthalic hydrazide), and
poly(terephthalic-chloroterephthalic hydrozide);
poly(amide-lydrazides) such as poly(tetrephthaloyl 1,4
aminobenzhydrazide) and those prepared from 4-amino-
benzhydrazide, osalic dibudrazide,-terephthalic
dihydrazide and paca-aromatic diacid chlorides; polyester
such as those of the compositions include poly(oxy-trans-
1,4-cyclohesyleneosycarbonyl-trans-1,4-cyclohesylenecarbony:.
-b-osy-1,4-phenyl-eneosyterephthaloyl) and poly(osy-cis-
1,4-cyclohesyleneosycarbonyl-trans-1,4-cyclohesylenecarbonyl
-b-osy-1,4-phenyleneosyterephthaloyl) in methylene
chloride-o-cresol poly[(osy-trans-1,4-cyclohesylene-
osycarbonyl-trans-1,4-cyclohexylenecarbonyl-b-osy-(2-methyl-
1,4-phenylene)osy-terephthaloyl)] in 1,1,2,2-tetrachloro-
ethane-o-chlorophenol-phenol (60:25:15 vol/vol/vol) and
poly[osy-trans-1,4-cyclohesyleneosycarbonyl-trans-1,4-
.
.
"...
' ,:, - ',, . ,. ." ,, : ,
;,, " - ' ' - ., ~
'091/07632 PCl'/~'S90/064j3
~ ~, r.. ,., ;
- 18 -
cyclohe~ylenecarbonyl-b-oxy(2-methyl-1,3-phenylene)o~y-
terephthaloyl] in o-chlorophenol; polyazomethines such as
those prepared from 4,4'-diamino~enzanilide and
terephthalaldephide, methyl-1,4-phenylenediamine and
S terephthalaldelyde; polyisocyamides such as poly( -phenyl
ethyl isoayamide), and poly(n-octyl isocyamide);
polyisocyanatis such as poly(n-octyl isocyanates) which
include poly(n-butyl isocyanate) and poly(n-hexyl
isocyanate); lytotropic crystalline polymers with
heterocylic unit such as poly(l,4-phenylene-2,6-
~enzobisthiazole)(PBT), poly(l,4-phneylene-2,6-
benzobisoxazole)(PB0), poly(l,4-phenylene-1,3,4-
oxadiazole), poly(l,4-phenylene-2,6-benzobisimidazole),
poly[2,5(6)-benzimidazole] (AB-PBI), poly[2,6-(1,4-.
phneylene)-4-phenylquinoline], poly[l,l~-(4,4~-
biphenylene)-6,6'-bis(4-phenylquinoline)];'
polyorganophosphazines such as polyphosphazine, .. -
polybisphenoxyphosphazine and poly[bis(2,2,2
trifluoroethyelene) phosphazine]; metal polymers such as.
those derived from by condensation of trans-bis(tri-n-
butylphosphine)platinum dichloride with a bisacetylene or
trans-bis(tri-n-butylphosphine)bis(1,4-butadinynyl)platinum
and similar combinations in the presence of cuprous iodine
and an amide; cellulose and cellose derivatives such as
esters of cellulose which include triacetate cellulose,
acetate cellulose, acetate-butyrate cellulose, nitrate,
and sulfate, ethers of cellulose which include ethyl ether
cellulose, hydroxymethyl ether cellulose, hydroxypropyl
ether cellulose, carbosymethyl ether cellulose, ethyl
hydroxyethyl ether cellulose, cyanoethylethyl ether
cellulose, ether-esters of cellulose such as acetosyethyl
ether cellulose and-benzoylosypropyl ether cellulose, and
urethane cellulose such as phenyl urethane cellulose;
theynotropic liquid cr-ystalline polymers such as
celluloses 'and their derivatives which include
hydrosypropyl cellulose, ethyl cellulose propionoxypropyl
cellulose; thermotropic copolyesters such as copolymers
6-hydroxy-2-naphthoic acid and p-hydorsy benzoic acid,
- ~ - '~ , . .
~0 9l/n7632 Pcr/~ssn/~)64;~
r~
- 19 -
copolymers of 6-hydro~y-2-naphthoic acid, terephthalic
acid and hydroquinose, and copolymers of poly(ethylene-
terephthalate~ and p-hydor~ybenzoic acid; thermotropic
polymerids and thermotropic copoly(amide-ester)s.
Also illustrative of useful organic filament for use
in the fabrication of backing layer 18 are those composed
of estended chain polymers formed by polymerization of -,~
-unsaturated monomers of the formula:
Rl R2-C ~ CH2
wherein:
Rl and R2 are the same or different and are
hydrogen,hydrosy, halogen, alkylcarbonyl, carbo~y,
alko~ycarbonyl, heterocycle or alkyl or aryl either
unsubstituted or substituted with one or more substituents
selected from the group consisting of alkosy, cyano,
hydrosy, alkyl and aryl. Illustrative of such polymers of
L,B-unsaturated monomers are polymers including
polystyrene, polyethylene, polypropylene,
poly(l-octadence), polyisobutylene, poly(l-pentene),
poly(2-methylstyrene), poly(4-methylstyrene),
poly(l-hesene), poly(l-pentene), poly(4-metho~ystrene),
poly(5-methyl-1-hesene), poly(4-methylpentene), poly
(l-butene), polyvinyl chloride, polybutylene,
polyacrylonitrile, poly(methyl pentene-l), poly(vinyl
alcohol), poly(vinylacetate), 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(l-pentene),
poly(4-methyl-1-butene), polytl-pentene), poly(4-
methyl-1-pentence, poly(l-hesane), poly(5-methyl-1-
he~ene), poly(l-octadence), poly(vinyl-cyclopentane),
poly(vinylcyclothesane), poly(~-vinyl-naphthalene),
poly(vinyl methyl ether), poly(vinyl-ethylether),
, s, "~ s~,,,.,, , ,~
.
' ~
,
UOgl/07632 PCT/~S90/06453
- 22 -
PAN filament should have a tenacity of at least about 10
g/denier and an energy-to-break of at least about 8
joule/g. PAN filament having a molecular weight of at
least about 4000,000, a tenacity o~ at least about 15 to
about 20 g/denier and an energy-to-break of at least about
8 joule/g is most useful in producing ballistics resistant
articles; and such filaments are disclosed, for e~ample,
in US 4,535,027.
In the case of aramid filaments, suitable aramid
filaments for use in the fabrication of girdle 14 are
those formed principally from aromatic polyamide are
described in US Patent No. 3,671,542, which is hereby
incorporated by reference. Preferred aramid filament will
have a tenacity of at least about 20 g/d, a tensile
lS modulus of at least about 400 g/d and an energy-to-break
at least about 8 joules/gram, and particularly preferred
aramid filaments 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 filaments 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
e~ample, poly(phenylenediamine terephalamide) filaments
produced commercially by Dupont Corporation under the
trade name of Kevlar 29, 49, 149 and 129 are particularly
useful in forming ballistic resistant composites. Also
useful in the practice of this invention is poly(meta-
phenylene isophthalamide) filaments produced commercially
by Dupont under the trade name Nome~.
In the more preferred embodiments of this invention,
backing layer 18 is formed of filaments arranged in a
network which can have various configurations. For
e~ample, a plurality of filaments can be grouped together i
to form a twisted or~untwisted yarn. The filaments or -
yarn may be formed as a flet knitted or woven (plain,
basked, sating and crow feet weaves, etc.) into a network,
or formed into a network by any of a variety of
conventional techniques. In the preferred embodiments of
". ' '' ' " ~ , .
.
- ., ~
,,
wosl/07632 PCT/~S90/064~3
- 23 -
the invention, the filaments are untwisted mono-filament
yarn wherein the filaments are parallel, unidirectionally
aligned. For e~ample, the filaments may also be formed
into nonwoven cloth layers by convention techniques.
Wetting and adhesion of fiber to the polymer
matrices, such as epo~y resins is enhanced by prior
treatment of the surface of the yarn. The method of
surface treatment may be chemical, physical or a
combination of chemical and physical actions. E~amples of
lO purely chemical treatments are used of SO3 or
chlorosulfonic acid. Examples of combined chemical and
physical treatments are corona discharge treatment or
plasma treatment using one of several commonly available
machines.
In the most preferred embodiments of this invention,
backing layer 18 is composed by one or more layers of
continuous fibers embedded in a continuous phase of matris
material which preferably substantially coats each
filament contained in the bundle of filaments. The manner
20 in which the filaments are dispersed may vary widely. The
filaments may be aligned in a substantially parallel,
unidirectional fashion, or filaments may be aligned in a
multidirectional fashion, or filaments may be aligned in a
multidirectional fashion with filaments at varying angles
25 with each other. In preferred embodiments of this
invention, filaments in each layer forming backing layer
18 are aligned in a substantially parallel, unidirectional
fashion such as in a prepreg, pultruded sheet a~d the like.
The matri~ material used in the formation of backing
30 layer 18 may vary widely. Illustrative of use for matris
materials are thermoplastic polymers such as polyesters,
polyamides, polyurethanes, polyolefins, polycarbonates,
polyamides, polyphenylosides, polyurethane elastomers,
polyestermides, polylactones, polyestercarbonates,
35 polyphenylene sulfides and the like; and thermosetting
resins such as epo~y resins, phenolic resins, vinyl ester
lesins, modified phenolic resins, unsaturated polyester,
allylic resins, alkyd resins, urethanes and melamine urea
.
,, , ~ .., ' , '
. .
.
wo 91 /07632 PCr/l S~0/06453
2 ~
- 24 -
resins and the like. A single material may be used as the
matri~ or blends can be used. In the preferred
embodiments of the invention, the matri~ material is a
mi~ture of a thermoplastic resins and a thermosetting
S resin. The preferred thermosetting material is a vinyl
ester resin and the preferred thermoplastic resin is a
polyurethane.
The proportions of matri~ to filament in backing
layer 18 is not critical and may vary widely depending on
10 a number of factors including, whether the matri~ material
has any ballistic-resistant properties of its own (which
is generally not the case) and upon the rigidity, shape,
heat resistance, wear resistance, flammability resistance
and other properties desired for backing layer 18. In
15 general, the proportion of matri~ to filament in backing
layer 18 may vary from relatively small amounts where the
amount of matri~ is about 10% by volume of the filaments
to relatively large amount where the amount of matri~ is
up to about 90~ by volume of the filaments. In the
20 preferred embodiments of this invention, matri~ amounts of
from about lS to about 80% by volume are employed. All
volume percents are based on the total volume of backing
layer 18. In the particularly preferred embodiments of
the invention, ballistic-resistant articles of the present
25 invention, layer 18 contains a relatively minor proportion
of the matri~ (e.g., about 10 to about 30% by volume of
composite), since the ballistic-resistant properties are
almost entirely attributable to the filaments, and in the
particularly preferred embodiments of the invention, the
30 proportion of the matris in backing layer 18 is from about
10 to about 30~ by weight of filaments.
Backing layer 18 can be fabricated using conventional
procedures. For e~ample, in those embodiments of the
invention where backing layer 18 is a metal, alloy or an
35 alloy or metal containing inorganic fibrous reinforced
layer 18 can be formed by conventional metal working
techniques. In the most preferred embodiments of the
invention in which backing layer 18 is a woven fabric
,
.',, ' ''
,, - ~
'. . '' '"
0 91 /07632 PCl /I,S90/064~3
- 25 -
composed of a polymeric material, backing layer 18 can be
fabricated using conventional fabric weaving techniques of
the type commonly employed for ballistic purposes such as
a plain weave or a Panama weave. In those preferred
embodiments of the invention in which backing layer 18 is
a network of polymeric fibers in a matri~, backing layer
18 is formed by molding the combination of fibers and
matri~ material in the desired configurations and amounts,
and then subjecting the combination to heat and pressure.
For e~tended chain polyethylene filaments used in the
most preferred embodiments, molding temperatures range
from about 20 to about 150 C, preferably from about 80 to
about 145 C, more preferably from about 100 to about 135
C, and more preferably from about 110 to about 130C. The
pressure may range from about 10 psi (69 kpa to about
10,000 psi (69,000 kpa). A pressure between about 10 psi
(69 kpa) and about 100 psi (690 kpa), when combined with
temperatures below about 100 C for a period of time less
than about 1.0 min.. may be used simply to cause adjacent
filaments to stick together. Pressures from about 100 psi
to about 10,000 psi (69,000 kpa), when coupled with
temperatures in the range of about 100 to about 155C for
a time of between about 1 to about 5 min., may cause the
filaments to deform and to compress together (generally in
a film-like shape). Pressures from about 100 psi (690
kpa) to about 10,000 psi (69,000 kpa), when coupled with
temperatures in the range of about 150 to about 155C for
a time of between 1 to about 5 mn., may cause the film to
become translucent or transparent. For polypropylene
filaments, the upper limitation of the temperature range
would be about 10 to about 20 C higher than for ECPE
filament.
In the most preferred embodiments of the invention,
the polymeric filaments (pre-molded if desired) are
3S pre-coated with the desired matri~ material prior to being
arranged in a network and molded into backing layer 18 as
described above. The coating may be applied to the
filaments in a variety of ways and any method known to
. :
;.,,
-
~09l/~7632 PCT/~SgO/064~3
F ~ _. t- 26 -
those of skill in the art for coating filaments may be
used. For e~ample, one method is to apply the matri~
material to the stretched high modulus filaments either as
a liquid, a sticky solid or particles in suspension, or as
fluidized bed. Alternatively, the matrix material may be
applied as a solution or emulsion in a suitable solvent
which does not adversely affect the properties of the
filament at the temperature of application. In these
illustrative embodiments, any liquid may be used.
However, in the preferred embodiments of the invention in
which the matri~ material is an elastomeric material,
preferred groups of solvents include water, paraffin oils,
ketones, alcohols, aromatic solvents or hydrocarbon
solvents or mi~tures thereof, with illustrative specific
solvents including paraffin oil, ~ylene, toluene and
octane. The techniques used to dissolve or disperse the
matris in the solvents will be those conventionally used
for the coating of similar elastomeric materials on a
variety of substrates. Other techniques for applying the
coating to the filaments may be used, including coating of
the high modulus precursor (gel filament) before the high
temperature stretching operation, either before or after
removal of the solvent from the filament. The filament
may then be stretched at elevated temperatures to produce
the coated filaments. The gel filament may be passed
through a solution of the appropriate matris material, as
for esample an elastomeric material dissolved in paraffin
oil, or an aromatic oraliphatic solvent, under conditions
to attain the desired coating. Crystallization of the
polymer in the gel filament may or may not have taken
place before the filament passes into the cooling
solution. Alternatively, the filament may be estruded
into a fluidized bed of the appropriate matris material in
powder form.
The proportion of coating on the coated filaments or
fabrics in backing layer 18 may vary from relatively small
amounts of (e.g. 1% by weight of filament~) to relatively
large amounts (e.g. 150~ by weight of filaments),
,,. , ' : :
-
. ~ . .
'
~ () 91/0/h37 PCT/1.~i90/06453
2 . . .;;
- 27 _
depending upon whether the coating material has any impac~
or ballistic-resistant properties of its own (which is
generally not the case) and upon the rigidity, shape, hea~
resistance, wear resistance, flammability resistance and
5 other properties desired for the comple~ composite
article. In general, backing layer 18 containing coated
filaments should have a relatively minor proportion of
coating (e.g. about 10 to about 30 percent by volume of
filaments), since the ballistic-resistant properties of
girdle 14 are almost entirely attributable to the
filament. Nevertheless, coated filaments with higher
coating contents may be employed. Generally, however,
when the coating constitutes greater than about 60% (by
volume of filament), the coated filament is consolidated
with similar coated filaments to forma fiber layer without
the use of additional matri~ material.
Furthermore, if the filament achieves its final
properties only after a stretching operation or other
manipulative process, e.g. solvent eschanging, drying or
the like, it is contemplated that the coating may be
applied to a precursor material of the final filament. IN
such cases, the desired and preferred tenacity, modulus
and other properties of the filament should be judged by
continuing the manipulative process on the filament
precursor in a manner corresponding to that employed on
the coated filament precursor. Thus, for esample, if the
coating is applied to the eserogel filament described in
US Application Serial No~ 572,607 of K~a-v-esh--~t al., and
the coated serogel filament is then stretched under
defined temperature and stretch ratio conditions, then the
filament tenacity and filament modulus values would be
measured on uncoated serogel filament which is similarly
stretched.
It is a most preferred aspect of the invention that
each filament be substantially coated with the matrix
material for the production of backing layer 18. A
filament is substantially coated by using any of the
coating processes described above or can be substantially
:,-
: . :
?
wosl/o7632 PCT/US90/064~3
- 28 -
coated by emploYing any other process capable of producing
a filament coated essentially to the same degree as a
filament coated by the processes described heretofore
(e.g., by employing known high pressure molding
techniques).
The filaments and networks produced therefrom are
formed into "simple composites" as the precursor to
preparing a more comple~ backing layer 18. The term,
~simple composite~, as used herein is intended to mean
composites made up of one or more layers, each of the
layers containing filaments as described above with a
single major matrix material, which material may include
minor proportions of other materials such as fillers,
lubricants or the like as noted heretofore.
The proportion of matris material to filament is
variable for the simple composites, with matris material
amounts of from about 5% to about 150 vol %, by volume of
the filament, representing the broad general range.
Within this range, it is preferred to use composites
having a relatively high filament content, such as
composites having only about 10 to about 50 vol % matrix
material, by volume of the composite, and more preferably
from about 10 to about 30 vol % matris material by volume
of the composite. `
Stated another way, the filament network occupies
different proportions of the total volume of the simple
composite. Preferably, however, the filament network
comprises at least about 30 volume percent of the simple
composite. For ballistic protecting, the filament network
comprises at least about 50 volume percent, more
preferably about 70 volume percent, and most preferably at
least about 75 volume percent, with the matris occupying
the remaining volume.
A particularly effective technique for preparing a
preferred composite of this invention comprised of
substantially parallel, undirectionally aligned filaments
includes the steps o~ pulling a filament or bundles of
filaments through a bath containing a solution of a matrix
.,, '
,
.
~091/07632 ~'CT/~.S90/~)64;3
- 29 -
material preferably, an matrix material, and
circumferentially winding this ~ilament into a single
sheet-like layer around and along a bundle of filaments
the length of a suitable form, such as a cylinder. The
solvent is then evaporated leaving a sheet-like layer of
filaments embedded in a matri~ that can be removed from
the cylindrical form. Alternatively, a plurality of
filaments or bundles of filaments can be simultaneously
pulled through the bath containing a solution or
dispersion of a matris material and laid down in closely
positioned, substantially parallel relation to one
another ron a suitable surface. Evaporation of the
solvent leaves a sheet-like layer comprised of filaments
which are coated with the matri~ material and which are
substantially parallel and aligned along a common filament
direction. The sheet is suitable for subsequent
processing such as laminating to another sheet to form
composites containing more than one layer.
Similarly, a yarn-type simple composite can be
produced by pulling a group of filament bundles through a
dispersion or solution of the matri~ material to
substantially coat each of the individual filaments, and
then evaporating the solvent to form the coated yarn. The
yarn can then, for esample, be employed to form fabrics,
25 which in turn, can be used to form more comples composite
structures. Moreover, the coated yarn can also be
processed into a simple composite by employing
conventional filament winding techniques; for example, the
simple composite can have coated yarn formed into
overlapping filament layers.
The number of layers of fibers included in backing
layer 18 may vary widely. In general, the greater the
number of layers the greater the degree of ballistic
protection provided and conversely, the lesser the number
of layers the lessor the degree of ballistic protection
provided.
One preferred configuration of backing layer 18 is a
laminate in which one or more layers of filaments coated
,' ' ' ' ' '' " ~ '
:, '' ''' ' ' :-
WOgl/07632 Pcr/~s9o/o6453
- 30 -
with matri~ material (pre-molded if desired) are arranged
in a sheet-like array and aligned parallel to one another
along a common filament direction. Successive layers of
such coated unidirectional filaments can be rotated with
respect to the previous layer after which the laminate can
be molded under heat and pressure to form the laminate.
An e2ample of such a layered vibration isolatinq layer is
the layered structure in which the second, third, fourth
and fifth layer are rotated 45 , 45 , 90 and 0 with
respect to the first layer, but not necessarily in that
order. Similarly, another esample of such a layered layer
12 is a layered structure in which the various
unidirectional layers forming girdle are aligned such that
the common filament a~is is adjacent layers is 0 , 90 .
FIG 2 shows a variant of the embodiment of FIG 1
which is indicated at 22. In composite 22, the ceramic
impact layer 10 is covered with cover layer 24 which
functions as an anti-spall layer to retain spall or
particles resulting from the shattering of ceramic bodies
20 by a striking projectile and to maintain ceramic bodies
20 in position. In FIG 2, cover layer 24 consists of top
cover 26 and release layer 28. Top cover 26 is formed
from a rigid material, as for esample, the materials
useful in the construction of backing layer 18.
Illustrative of such materials are metals such as steel,
titanium and aluminum alloys, or of a rigid high strength
polymeric composite such as a thermoplastic resin such as
a polyurethane, a polyester or a polyamide, a thermo-
setting resin such as eposy, phenolic or vinyl ester resin
reinforced with polymeric filaments such as aramid or
estended chain polyethylene or inorganic filaments such as
S-glass fibers, silicon carbide fibers, E-glass fibers,
carbon fibers, boron fibers and the like. Release layer
28 is formed from materials used in the fabrication of
backing layer 3g which are fibrous composites comprised of
a fiber network which optionally may be in a matrix in a
matris. Release layer 32 functions to eliminate or to
substantially reduce the strain on unhit ceramic bodies 20
.,, : , ::
.. . ..
"
O91/07632 PCr/~ 90/064~3
Z~
-- 3 1
in the deformation of the composites from impact by the
projectile. The construction of ceramic impact layer 12,
peripheral hard impac~ layer retaining means 14 and
peripheral ceramic body retaining means 16, and their
5 materials of construction are the same as in article 10 of
FIG 1.
FIG 3 depicts an armor plate composite 30 which
differs from the armor plate 22 of FIG 2 by the inclusion
of a vibration isolating layer 32, corresponding parts
being referred to by like numerals. Vibration isolating
layer 32 minimizes the shock and vibration resulting from
the impact of the projectiles which inhibits the
transmission of shock and vibration to portions of ceramic
impact layer 12 away from the point of impact which
substantially increases the multiple hit capability of the
armor. In armor plate 30, vibration isolating layer 32 is
composed of three superimposed constituent, essential
layer 34 and two optional layers 36 and 38. Optional
layers 34 and 38 are thin layers of a metal or non-metal
rigid material such as the materials used in the
fabrication of backing layer 18 and layer 34 is one or
more layers comprising a network of polymeric fibers (such
as the e~tended chain polyethylene fibers) used in the
fabrication of backinq layer 18, which may be optionally
and preferably in a matris. ~igid layers 42 and 44
function to improve the overall performance of vibration
isolation layer 32, to improve the surface characteristics
of vibration isolation layer 32, to provide a surface on
which ceramic bodies 20 can be attached; and to retain
dimensional stability (i.e. flatness and straightness) of
the surface subject severe impact deformation. At their
contact points, constituent layer 34, 36 and 38 are bonded
together with a suitable agent such as an adhesive as for
esample, the fle~ible adhesives described above for use to
bond ceramic bodies 20 to backing layer 18 such as a
polysulfide or an epo~y. In composite 30, backing layer
18 is of double layer construction and includes rigid
layer 40 which is formed of a metal or rigid polymeric
- '
. . - , .
. ' ,, , .
,
WO91/07632 PCT/~S90/064~3
- 32 - ~d '~. J . ~' ~
material such as glass filled epoxy resin and ballistic
resistant composite layer 42 and preferably for~ed from
high strength fibers such as Spectra polyethylene fibers
or aramid fibers i~ a polymeric matrix. The construction
of cover layer 30, ceramic impact layer 12, peripheral
hard impact layer retaining means 14 and peripheral
ceramic body retaining means 16 and their materials of
construction are the same as in composite 10 of FIG 1.
Comple~ ballistic articles of this invention have
many uses. For e~ample, such composites may be
incorporated into more comple~ composites to provide a
rigid complex composite article suitable, for e~ample, as
structural ballistic-resistant components, such as
helmets, structural members of aircraft, and vehicle
panels.
The following e~amples are presented to provide a
more complete ~nderstanding of the invention. The
specific techniques, condition, materials,proportions and
reported data set forth to illustrate the principles of
the invention are e~emplary and should not be construed as
limiting the scope of the invention.
EXAMPLE I
A panel consisting of a 4 by 4 checker board with
square cell of dimensions of 4 (10.2 cm) by 4~ (10.2 cm)
by 1~2~ (1.3 cm) depth was constructed. The cells of the
panel were divided with a 0.06" (0.15 cm) thick aluminum
barrier wall. Each cell was filled with one alumina
tile. The panel was constructed with Spectra composite
as backing material to prevent damages of the tiles from
shocks and vibrations induced by the ammunition hits. The
checker board was placed into a 16.25" (41.3 cm) by 16.25
(14.3 cm) by 1/2~ (1.3 cm) aluminum frame, and it was
covered with a piece of 1/8" (0.319 cm) thick aluminum. A
piece of Spectra fabric which was used as a release
material was placed in between the surface of the
segmented layer of tiles and the cover. The style of the
.
, ": "' ` ''~ '
, `
... . . . . .
WO9l/07632 PCT/~S90/06453
., , ..~ . .,
- 33 -
fabric used was 952 plain 650d. The whole unit was
mounted on a rigid, 21/32" (1.67 cm) thick, glass
reinforced plastic (GRP) plate. The adhesive used was
sold by Semco/Bancroft Corp. of New Jersey under a trade
name of P/S 890-B 1/2 for the adhesive and the trade name
for the curing agent was PR-890-B 1/2. The composition
used was 10 to 1 ratio between the adhesive and the curing
agent. The cure time required was around 12 hours, and
the tack free time was about 2 hours. This adhesive meets
the MIL-S-8802E specs.
Ex~oeL~
The multiple-hit capability of the article of EXAMPLE
I was evaluated. In these esperiments, the tiles were
shot by a projectile traveling at a speed around 3100
ft/sec.(945 m/sec). After 12 hits, the remaining four (4)
unhit tiles remained undamaged. The location and
distribution of cracks were confined in the panel composed
of brittle solids at the point of impact. The cracks and
flaws initiated around the indentation were localized only
at the point of contact loading for the tile which was hit
and did not propagate in the entire panel.
Spalls/particles created by the shattering of tile upon
impact~are retained locally around the point of impact.
Visual inspect~on of neighboring tiles found that they
were not damaged by spalls/particles created by
comminution of the tiles on impact.
Ex~MpLE III
Esample II was repeated with the esception that
marble tiles were used and the flesible bonding agent was
replaced by inflesible vinyl ester resin. One Thousand
grams of a misture of a vinyl ester resin (VE 8520 sold by
Interplastics) and pero~ide (Benzoate peroside sold by
Lucidol under the trade name Luperco AFR-400) and a
promoter (N, N, dimetyl anilane) was poured in the mold
.,
,
~'0 91/07632 PCr/l~i90/06453
- 34 -
until the article was completely covered. The composition
of the vinyl ester resin/peroside/promotor is I0/0.l/0.006.
The material was cured for two hours at room temperature
under pressure. The article was evaluated as in EXAMPLE
II, and it e~hibited multiple hit capability.
EXAMPLE IV
A panel was constructed as described in Esample II
with the exception that no Spectra~composite vibration and
shock isolation material was used. The panel was tested
following the conditions described in E2ample II. While
the panel e~hibited multiple hit capability at was not as
effective as the panel of Esample I. Cracks were found
around the neighboring unhit tiles after the impact.
Therefore, the perform~nce at the center of tile and at
the seam area of the segmented for another hit was not as
good as in the panel of Esample I.
~xAMpLE V
A panel was constructed following the procedure
described in E~ample II with the esception that no elastic
barrier wall was used. The panel was tested following the
conditions described in Esample II. While the panel
eshibited multiple hit capability, it was not as effective
as the panel of E~ample I. Cracks were found around the
neighboring unhit tiles after the impact. Therefore, the
performance at the center of tile and at the seams between
adjacent tiles for another hit was not as good as in the
panel of E~ample I.
EXAMPLE VI
A panel was constructed following the procedure
described in E~ample I with the esception that a rigid
bonding agent (thermosetting polyester resin) was used to
bond the ceramic bodies to the backing layer. ~he panel
.. ,. , . ~,.. ; ..... .......
.
' ' ' ~ " ~ ,
, ,, ~ ' ,:
wO9l/07632 PCT/~S90/06453
- 35 -
was tested fol~owing the conditions described in Example
I. While the panel e~hibited ~ultiple hit capability, it
was not as effective as the panel of E~ample I. Cracks
were found around the neighboring unhit tiles after the
impact. Also, some of the neighboring tiles were
delaminated from the substrata. Therefore, the
performance at the center of tile and at the seams between
adjacent tiles for another hit was not as good as in the
panel of Esample I.
EXAM~PL~ VII
A panel was constructed following the procedure
described in E~ample I with the e~ception that no release
material was used. The panel was tested following the
conditions described in Esample II. While the panel
exhibited multiple hit capability, it was not as effective
as the panel of E~ample I. Cracks were found around the
neighboring unhit tiles after the impact.
EXAMPLE VIII
The efficiency of the penetration resistance of
E~ample I was evaluated at the center of tile, seam, edge,
and corner, following the e~perimental procedure described
in Esample II. It was found that, compared to the center
of tile, he efficiency was at least 99% for the seam,
adge, and corner.
COMPARATIVE EXAMPLE I
A panel was constructed following the procedure
described in Esample I with the e~ception that no
peripheral frame was used to surround the edges of the
seqmented layer of tiles. The panel was tested following
the conditions described in Esamples II. The performance
of the edges reduced drastically, down to about 20% of the
performance at the center of the tiles. Cracks were found
.; ' ,
.
WO91/07632 PCT/~S90/06453
r;1t ' ~ ">~ ~
around the neighboring unhit tiles after the impact.
Also, some of the neighboring tiles were delaminated from
the substrata. Therefore, the performance at the
neighboring areas of the hit for another hit was poor, and
the panel did not e~hibit acceptable multiple hit
capability.
; , ,
.
', ; " '",
