U.S. patent application number 13/134742 was filed with the patent office on 2012-10-25 for ballistic-resistant panel including high modulus ultra high molecular weight polyethylene tape.
Invention is credited to Kenneth C. Harding, Fielder Stanton Lyons, Jeffrey A. Mears, Joseph Mitchell, Lisa Owen, Peter Anthony Russell, Gene C. Weedon.
Application Number | 20120266744 13/134742 |
Document ID | / |
Family ID | 40229315 |
Filed Date | 2012-10-25 |
United States Patent
Application |
20120266744 |
Kind Code |
A1 |
Lyons; Fielder Stanton ; et
al. |
October 25, 2012 |
Ballistic-resistant panel including high modulus ultra high
molecular weight polyethylene tape
Abstract
A ballistic-resistant panel in which the entire panel or a
strike-face portion thereof is formed of a plurality of sheets of
high modulus high molecular weight polyethylene tape. The sheets of
high modulus polyethylene tape can be in the form of cross-plied
laminated layers of tape strips or a woven fabric of tape strips.
The strips of UHMWPE tape include a width of at least one inch and
a modulus of greater than 1400 grams per denier. The
ballistic-resistant panel may include a backing layer of
conventional high modulus fibers embedded in resin. A wide variety
of adhesives were found acceptable for bonding the cross-plied
layers of high modulus polyethylene tape together for forming the
ballistic-resistant panels of the present invention.
Inventors: |
Lyons; Fielder Stanton;
(Phoenix, AZ) ; Harding; Kenneth C.; (Midlothian,
VA) ; Owen; Lisa; (Charlotte, NC) ; Mitchell;
Joseph; (Concord, NC) ; Weedon; Gene C.;
(Richmond, VA) ; Mears; Jeffrey A.; (Chandler,
AZ) ; Russell; Peter Anthony; (Wilmington,
OH) |
Family ID: |
40229315 |
Appl. No.: |
13/134742 |
Filed: |
June 15, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11881863 |
Jul 30, 2007 |
7964267 |
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13134742 |
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11821659 |
Jun 25, 2007 |
7976930 |
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11881863 |
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11787094 |
Apr 13, 2007 |
7964266 |
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11821659 |
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Current U.S.
Class: |
89/36.02 ;
89/912; 89/917 |
Current CPC
Class: |
B32B 27/08 20130101;
B29K 2023/0683 20130101; B32B 5/022 20130101; B32B 37/1207
20130101; Y10T 428/24074 20150115; Y10T 442/2623 20150401; B29C
70/04 20130101; B32B 2307/558 20130101; B32B 2255/02 20130101; B29K
2995/0089 20130101; B32B 27/12 20130101; F41H 5/0478 20130101; Y10T
428/24479 20150115; B32B 2571/02 20130101; B32B 7/12 20130101; Y10T
428/2495 20150115; B32B 2260/023 20130101; B32B 27/32 20130101;
B29C 33/68 20130101; B32B 2255/26 20130101; B32B 2260/046 20130101;
B29C 70/202 20130101; B32B 5/26 20130101; B29K 2223/0683 20130101;
F41H 5/0485 20130101; Y10T 428/2913 20150115 |
Class at
Publication: |
89/36.02 ;
89/912; 89/917 |
International
Class: |
F41H 5/04 20060101
F41H005/04 |
Claims
1. A ballistic-resistant panel comprising: a metallic strike-face;
a backing including a plurality of interleaved layers of
non-fibrous ultra high molecular weight polyethylene (UHMWPE) tape;
and said UHMWPE tape including a tensile modulus of at least 1,400
grams per denier.
2. The ballistic-resistant panel of claim 1 wherein said metallic
strike-face includes a layer of high hardness steel and a layer of
aluminum.
3. The ballistic-resistant panel of claim 2 wherein said layer of
high hardness steel is 0.25 inch thick; said layer of aluminum is
1.5 inches thick; and said aluminum is grade 6061 aluminum.
4. The ballistic-resistant panel of claim 1 wherein said backing
includes an areal density of 1.6 pounds per square foot.
5. The ballistic-resistant panel of claim 1 wherein said UHMWPE
tape includes strips of tape having a width of at least 1.0 inch; a
viscosity-average molecular weight of at least 2,000,000; and a
thickness of between 0.0015 and 0.004 inch.
6. The ballistic-resistant panel of claim 1 including an adhesive
on at least one side of said interleaved layers of said non-fibrous
UHMWPE tape.
7. A ballistic-resistant panel comprising: a metallic strike-face;
a backing including a first portion and a second portion; said
first portion consisting of a plurality of interleaved layers of
non-fibrous ultra high molecular weight polyethylene (UHMWPE) tape;
and said second portion consisting of a plurality of interleaved
layers of cross-plied fibers embedded in resin.
8. The ballistic-resistant panel of claim 7 wherein said UHMWPE
tape includes a tensile modulus of at least 1,400 grams per
denier.
9. The ballistic-resistant panel of claim 7 wherein said metallic
strike-face includes a layer of high hardness steel and a layer of
aluminum.
10. The ballistic-resistant panel of claim 7 wherein said layer of
high hardness steel is 0.25 inch thick; and said layer of aluminum
is 1.0 inch thick.
11. The ballistic-resistant panel of claim 7 wherein said aluminum
is grade 6061 aluminum.
12. The ballistic-resistant panel of claim 7 wherein said backing
includes an areal density of at least 2.5 pounds per square
foot.
13. The ballistic-resistant panel of claim 7 wherein said UHMWPE
tape includes strips of tape having a width of at least 1.0 inch; a
viscosity-average molecular weight of at least 2,000,000; and a
thickness of between 0.0015 and 0.004 inch.
14. (canceled)
15. The ballistic-resistant panel of claim 13 wherein said tape
strips include a width to thickness ratio of at least 400:1 and a
denier of 6,000 or greater.
16. A ballistic-resistant panel comprising: a plurality of layers
of non-fibrous ultra high molecular weight polyethylene (UHMWPE)
tape; each of said layers of non-fibrous UHMWPE tape including a
plurality of monolithic tape strips woven together to form a woven
layer; said non-fibrous UHMWPE tape strips including a modulus of
greater than 1,400 grams per denier; said plurality of woven layers
of non-fibrous UHMWPE tape molded together by heat and
pressure.
17. The ballistic-resistant panel of claim 16 wherein said
ballistic-resistant panel includes an areal density of 2.2 pounds
per square foot.
18. The ballistic-resistant panel of claim 16 wherein each of said
woven layers are interleaved with a low density polyethylene film,
said low density polyethylene film acting as a binder for binding
together said woven tape strips upon application of heat and
pressure; and said low density polyethylene film is 18-microns
thick.
19. The ballistic-resistant panel of claim 16 wherein said
non-fibrous UHMWPE tape includes a viscosity-average molecular
weight of at least 2,000,000; a width of at least 1.0 inch; and a
thickness of between 0.0015 and 0.004 inch.
20. The ballistic-resistant panel of claim 16 wherein said heat of
molding is 250 degrees F. and said pressure is 500 psi.
Description
[0001] This application is a Continuation of U.S. patent
application Ser. No. 11/881,863, filed on Jul. 30, 2007 and
entitled "Ballistic-Resistant Panel Including High Modulus Ultra
High Molecular Weight Polyethylene Tape", and is a
Continuation-In-Part of U.S. patent application Ser. No.
11/821,659, filed on Jun. 25, 2007 and entitled "Non-Fibrous High
Modulus Ultra High Molecular Weight Polyethylene Tape for Ballistic
Applications", and is a Continuation-In-Part of U.S. patent
application Ser. No. 11/787,094, filed on Apr. 13, 2007 and
entitled "Wide Ultra High Molecular Weight Polyethylene Sheet and
Method of Manufacture", of which the entire contents of said
applications are incorporated herein in their entirety by reference
thereto.
FIELD OF THE INVENTION
[0002] The present invention relates to survivability enhancement
and more particularly to a ballistic laminate constructed of a
plurality of layers of non-fibrous high modulus ultra high
molecular weight polyethylene.
BACKGROUND OF THE INVENTION
[0003] Survivability enhancement is a well-known objective for
armored vehicles or fixed or mobile armored structures in a combat
or other high threat environment. If a high-energy projectile
strikes a vehicle, the survivability of the occupants and the
vehicle can be compromised by the release of spall, which is a
spray of high velocity metallic or ceramic debris into the
vehicle's interior. Vehicles, ships, aircraft, or structures in a
high threat environment are therefore frequently equipped with a
spall liner, which is designed to suppress the spall generated when
a projectile penetrates the vehicle's interior.
[0004] Spall liners are typically comprised of a compressed panel.
The compressed panel usually includes a plurality of layers of high
modulus, high tensile strength fabric bonded together by a resinous
adhesive. If a projectile penetrates the armor of a vehicle, the
spall liner absorbs the force of the projectile, with each separate
layer delaminating and absorbing some portion of the force of the
projectile and thereby dissipating the energy of the projectile as
it advances through the spall liner.
[0005] Although many different spall liners have been proposed,
further enhancements in spall suppression are highly desirable for
increasing survivability of armored vehicles and structures.
SUMMARY OF THE INVENTION
[0006] The invention is a ballistic-resistant panel formed of a
plurality of sheets of high modulus high molecular weight
polyethylene tape. The sheets of high modulus polyethylene tape
include tape strips bonded together at their edges by heat and
pressure or by thermoplastic adhesive combined with heat and
pressure. The strips of UHMWPE (ultra high molecular weight
polyethylene) tape include a width of at least one inch and a
modulus of greater than 1400 grams per denier. The
ballistic-resistant panel may include a backing layer of
conventional high modulus fibers embedded in resin. A wide variety
of adhesives were found acceptable for bonding the sheets of high
modulus polyethylene tape together for forming the
ballistic-resistant panels of the present invention.
OBJECTS AND ADVANTAGES
[0007] The ballistic-resistant panel formed of UHMWPE (ultra high
molecular weight polyethylene) Tensylon tape of the present
invention includes several advantages over the prior art,
including:
[0008] (1) The ballistic resistance is improved over ballistic
panels formed entirely of conventional ballistic fibers.
[0009] (2) The UHMWPE Tensylon tape of the present invention can be
produced at a substantially lower price than conventional ballistic
fibers. Significant cost savings are therefore obtained by
replacing a portion of the conventional high modulus component with
the high modulus UHMWPE tape of the present invention.
[0010] (3) Forming the ballistic-resistant panel or the strike-face
portion of monolithic UHMWPE tape reduces or eliminates joints or
seams, thereby improving the ballistic resistance of the ballistic
laminate.
[0011] (4) Forming the strike-face portion of monolithic UHMWPE
tape provides structural support to the laminate and reduces
delamination after a ballistic event.
[0012] (5) The UHMWPE tape of the present invention may be formed
into sheets or layers by weaving the wide tapes into a woven
structure such as a simple basket weave or by simply butting
together the strips of tape edge to edge, or by overlapping the
edges slightly, and then pressing with pressure, heat and pressure,
or by coating with adhesive and pressing. This is vastly simpler
and cheaper than forming a sheet or layer from fibers, which
requires many more individual ends or packages and lamination with
an adhesive or processing by weaving, knitting, or
cross-stitching.
[0013] (6) The amount of adhesive required to mold a ballistic
laminate with a strike-face according to the present invention is
significantly lower than that required for a ballistic laminate
formed of conventional ballistic fibers. The smooth surface area of
the high modulus tape used in the strike-face portion of the
ballistic-resistant panel enables a lower adhesive to UHMWPE ratio
than is available with ballistics panels formed from conventional
UHMWPE. The effectiveness of conventional ballistic-resistant
panels is generally negatively affected by the higher adhesive
ratios, as the adhesive portion adds weight to the laminate but
does not contribute to the ballistic resistance unless the adhesive
is specifically designed to produce controlled delamination.
[0014] These and other objects and advantages of the present
invention will be better understood by reading the following
description along with reference to the drawings.
DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a schematic representation of a production process
for laminating UHMWPE tape with adhesive in order to produce layers
for forming a ballistic laminate according to the present
invention.
[0016] FIG. 2 is a schematic representation of a second production
process for laminating UHMWPE tape with adhesive for the production
of a ballistic laminate according to the present invention.
[0017] FIG. 3 is a schematic representation in perspective view of
two sheets or layers of adhesive-coated unidirectional non-fibrous
UHMWPE tape prior to being fused together with heat and pressure to
form a cross-plied laminate for use in the construction of a
ballistic laminate according to the present invention.
[0018] FIG. 4 is a schematic representation as viewed from the side
of two sheets of unidirectional non-fibrous UHMWPE tape prior to
being fused together with heat and pressure to form a cross-plied
laminate.
[0019] FIG. 5 is an illustration depicting the forming of a
ballistic-resistant panel with cross-plied sheets of
adhesive-coated Tensylon and cross-plied sheets of conventional
high modulus fibers embedded in resin.
[0020] FIG. 6 is a graph depicting ballistic resistance at various
molding temperatures and at two separate molding pressures for 2.0
psf panels having 100% Tensylon tape as the high modulus
component.
TABLE OF NOMENCLATURE
[0021] The following is a listing of part numbers used in the
drawings along with a brief description:
TABLE-US-00001 Part Number Description 20 laminator/fuser 22 unwind
shaft 24 Tensylon tape 26 second unwind shaft 28 adhesive 30 third
unwind shaft 32 fourth unwind shaft 34 silicone release paper 36
nip rolls 38 adhesive coated Tensylon web 40 fusing oven 42 chilled
platen 44 adhesive coated unidirectional tape 50 laminator/fuser 52
adhesive coated release roll 54 release liner 60 top sheet of
adhesive-coated unitape 62 bottom sheet of adhesive-coated unitape
64 strip of Tensylon unidirectional tape 66 joint areas 68 adhesive
layer 70 cross-plied sheet of adhesive-coated Tensylon 72
cross-plied sheet of adhesive-coated Tensylon 74 cross-plied sheet
of convention fibers in resin 76 cross-plied sheet of convention
fibers in resin
DETAILED DESCRIPTION OF THE INVENTION
[0022] The present invention relates to ballistic laminates having
a plurality of layers of high modulus material, either all or some
portion of which layers are constructed of non-fibrous, high
modulus, ultra high molecular weight polyethylene tape of the type
described in U.S. patent application Ser. No. 11/787,094, filed on
Apr. 13, 2007, the contents of which are incorporated herein in
their entirety by reference thereto. The non-fibrous, high modulus,
UHMWPE tape is produced by Tensylon High Performance Materials,
Inc. of Monroe, N.C., and sold under the name TENSYLON.RTM.. As
used in this application, the term "high modulus" refers to
materials having a modulus greater than 1,000 grams per denier
(gpd).
[0023] In order to form an improved strike-face for a
ballistic-resistant panel according to the present invention,
adhesive was applied to one side of a plurality of webs of
unidirectional UHMWPE tape. The webs of adhesive-coated unitape
were bonded into a unidirectional or unitape sheet, sheeted, and
then cross-plied with additional sheets of adhesive-coated unitape.
The cross-plied sheets were molded by heat and pressure into a
ballistic laminate. Several conventional adhesives were tested for
their effectiveness in forming a ballistic laminate. The test
procedure included the following steps: [0024] (1) Comparing
various adhesives for bonding UHMWPE tape for the purpose of
forming unidirectional material for use in bidirectional cross ply;
[0025] (2) Evaluating unidirectional tape lamination capability and
consolidation capability; [0026] (3) Forming each adhesive variant
into a nominal 2.0 pounds per square foot (psf) test panel at 150
psi and into a second 2.0 psf panel at 3000 psi; and [0027] (4)
Testing the resultant test panels for ballistic performance.
[0028] In order to test the effectiveness of TENSYLON.RTM.
non-fibrous, high modulus UHMWPE tape as a high modulus component
in ballistic-resistant panels, adhesive was applied to one side of
Tensylon 19,000 denier tape, hereinafter "Tensylon tape". The
19,000 denier Tensylon tape included nominal dimensions of 1.62
inches in width, 0.0025 inch in thickness, and a tensile modulus of
at least 1,400 grams per denier (gpd). Some of the adhesives were
in the form of adhesive scrims, which were laminated to one side of
the Tensylon tape, and others were resinous adhesive dispersed in a
solvent, which was coated on a release film and then transferred to
one side of the Tensylon tape. Preferably, the Tensylon tape has
viscosity-average molecular weight of at least 2,000,000, a width
of at least 1.0 inch, a thickness of between 0.0015 and 0.004 inch,
a width to thickness ration of at least 400:1, a denier of 6,000 or
greater, and a modulus of greater than 1,400 grams per denier.
[0029] With reference to FIG. 1, there is shown a laminator/fuser
20 for laminating adhesive scrims to the Tensylon tape. The
laminator/fuser 20 included an unwind shaft 22 with eight rolls of
1.62-inch wide Tensylon tape 24 assembled thereon. Each roll
included independent brake tension controls. A second unwind shaft
26 contained a roll of adhesive 28. A third unwind shaft 30 and
forth unwind shaft 32 contained rolls of silicone release paper 34.
The Tensylon tape 24, adhesive 28, and silicone release paper 34
were laminated together at nip rolls 36 thereby forming adhesive
coated Tensylon web 38 sandwiched between the two silicone release
liners 34. The silicone release liners 34 prevented the adhesive
coated Tensylon web 38 from sticking to any rollers in the oven
during fusing. The adhesive coated Tensylon web 38 was then
conveyed through a fusing oven 40 to cure the thermoplastic
adhesive. A chilled platen 42 cooled the Tensylon/adhesive laminate
38 as it exited the fusing oven 40. After cooling, the release
liners 34 were removed from the Tensylon/adhesive laminated web 38
thereby formed an adhesive-coated roll of unidirectional Tensylon
44 at a nominal width of 13.0 inches. The laminator/fuser operated
at a line speed of 10 to 20 feet per minute and with fusing oven 40
temperatures between 230.degree. F. and 260.degree. F.
[0030] For those adhesives in the form of a resin suspended in a
solvent, the resin was applied to one side of a silicone release
sheet. With reference to FIG. 2, there is shown a laminator/fuser
50 in which the adhesive-coated silicone release roll 52 was
mounted on an unwind shaft 30 with Tensylon tape 24 on unwind shaft
22. The adhesive-coated silicone release web 52 was then nipped
against the 1.62-inch wide Tensylon webs that were butt-jointed
together at the nip 36. At the nip the adhesive was transferred to
the Tensylon web and the eight 1.62-inch Tensylon webs were fused
into one sheet as has been described in U.S. patent application
Ser. No. 11/787,094, filed Apr. 13, 2007, the contents of which are
incorporated herein in their entirety by reference thereto. The
adhesive-coated Tensylon 38 was then conveyed through the remainder
of the laminator/fuser 50 and the release liner 54 removed from the
13.0-inch nominal width Tensylon/adhesive-coated web 38.
[0031] The specific adhesives tested and significant measured
properties are presented in Table 1 below:
TABLE-US-00002 TABLE 1 Adhesives Tested for effectiveness in
bonding Tensylon tape into a ballistic laminate: Adhesive Chemical
Melt Temperatures Measured Coat Code Composition (degrees C.)
Weight (gsm) A1 Polyamide 100-115 6.2 B1 Polyolefin 93-105 6.0 C1
Ethylene Vinyl 98-112 4.7 Acetate Copolymer D1 Polyurethane 70-100
16.7 E1 Ethylene Acrylic 88-105 N/A Acid Copolymer F1 Polystyrene
Isoprene N/A 6.0 Copolymer G1 Polyamide N/A 5.0 H1 Polyurethane N/A
5.0
[0032] The adhesives tested included Polyethylene-PO4401 (A1),
Polyethylene-PO4605 (B1), Polyethylene-DO184B (C1),
Polyurethane-DO187H (D1), and Polyethylene-DO188Q (E1), which are
all available from Spunfab, Ltd. of Cayahoga Falls, Ohio; Kraton
D1161P (F1), which is available from Kraton Polymers U.S., LLC of
Houston, Tex.; Macromelt 6900 (G1), which is available from Henkel
Adhesives of Elgin, Ill.; and Noveon-Estane 5703 (H1), which is
available from Lubrizol Advanced Materials, Inc. of Cleveland,
Ohio. Adhesives A1 through E1 were applied to the Tensylon tape by
the laminator/fuser 20 depicted in FIG. 1. Adhesives F1 through H1,
which were dispersed in solvents, were coated on a release film and
then transferred to one side of the Tensylon tape.
[0033] The adhesive-coated unidirectional Tensylon tape, commonly
termed "unitape" and consisting of eight strips of UHMWPE tape
fused at their edges, was then cut into 12-inch by 12-inch sheets.
FIGS. 3 and 4 depict two sheets 60 and 62 of adhesive-coated
unitape consisting of strips of Tensylon UHMWPE tape 64 fused at
joint areas 66. The joint areas 66 are depicted for clarity in
describing the direction of orientation of the UHMWPE tape in FIG.
3, it should be understood that the UHMWPE tape strips 64 are
rendered substantially transparent when bonded as described herein
therefore making the joint areas 66 appear homogenous with the
sheet. The bonding of non-fibrous, high modulus, ultra high
molecular weight polyethylene Tensylon tape is described in detail
in U.S. patent application Ser. No. 11/787,094, filed on Apr. 13,
2007, which has been incorporated herein by reference. The top
sheet 60 of adhesive-coated unitape is oriented at 90.degree. with
respect to the bottom sheet 62. An adhesive layer 68, shown as a
transparent layer of adhesive in FIGS. 3 and 4, is bonded to each
sheet 60, 62 in the manner described above. As the adhesive is
thermoplastic, the two sheets 60, 62 of adhesive-coated unitape are
pressed together with heat and pressure which causes the two sheets
to bond together into a cross-plied sheet of Tensylon UHMWPE with
the bonded sheets cross-plied in the 0.degree. and 90.degree.
direction.
[0034] To form a ballistic-resistant panel, cross-plied sheets of
adhesive-coated Tensylon were stacked until a stack of cross-plied
Tensylon of approximately 2.0 psf (pounds per square foot) was
obtained. Several of the nominal 2.0 psf stacks were pressed at a
pressure of 150 psi and several at a pressure of 3,000 psi. The
press cycle included 30 minutes at a temperature of 250.degree. F.
to 260.degree. F. and cooling under full pressure to below
120.degree. F. before release thereby forming ballistic-resistant
panels of nominally 2.0 psf areal density.
[0035] With reference to FIG. 5, a simplified illustration depicts
the forming of the preferred embodiment of a ballistic-resistant
panel with cross-plied sheets or laminates of adhesive-coated
Tensylon 70 and 72 and cross-plied sheets of conventional high
modulus fibers embedded in resin 74 and 76. The cross-plied sheets
of adhesive-coated Tensylon 70 and 72 are stacked on top of stacked
cross-plied sheets of conventional high modulus fibers 74 and 76
and pressure and heat are applied to bond the sheets into a
ballistic-resistant panel. As an example, to form a 2.0 psf
ballistic-resistant panel having a 50/50 ratio by weight of
Tensylon and conventional fiber, a plurality of sheets of
cross-plied conventional fibers embedded in resin are laid down
until a weight of approximately 2.0 psf is obtained. Cross-plied
sheets of adhesive-coated Tensylon are then stacked on top of the
cross-plied sheets of conventional high modulus fibers until a
total weight of approximately 2.0 psf was obtained. Heat and
pressure are then applied to fuse the cross-plied layers of
Tensylon and conventional fibers into a ballistic-resistant
panel.
[0036] The ballistic-resistant panels were then tested for
ballistic resistance. Projectiles of .30 caliber FSP (Fragment
Simulated Projectile) per MIL-P-46593A were fired at the 2.0 psf
test panels to obtain ballistics properties of the panels bonded
with the various adhesives. The velocities in fps (feet per second)
at which 50% of the projectiles failed to penetrate the target
(V.sub.50) were determined per MIL-STD-662F. Data for the resultant
ballistic-resistant panels formed at 150 psi are shown in Table 2
and data for the resultant ballistic-resistant panels formed at
3,000 psi are shown in Table 3 below:
TABLE-US-00003 TABLE 2 Data Results for Ballistic-resistant panels
of UHMWPE tape formed with various adhesives at Molding Pressure
150 psi and Ballistic Test Results: Adhe- Average Adhesive sive
Adhe- Areal 0.30 Cal Descrip- Weight sive Density FSP V.sub.50 tion
Adhesive ID (gsm) (wt %) (psf) (fps) A1 Polyamide 5.93 10.4 2.01
1873 A1 Polyamide 3.10 5.7 1.88 1984 C1 Ethylene Vinyl 5.93 10.4
2.03 1957 Acetate Copolymer D1 Polyurethane 15.25 22.9 2.02 1818 E1
Ethylene Acrylic 5.93 10.4 2.02 1832 Acid Copolymer B1 Polyolefin
5.93 10.4 2.01 1937 B1 Polyolefin 3.10 5.7 2.05 1878 F1
Polystyrene- 7.40 12.6 2.01 2057 Isoprene Copolymer F1 Polystyrene-
5.70 10.0 2.07 2124 Isoprene Copolymer Dyneema Polystyrene- -- --
1.99 2275 HB2 Isoprene Dyneema Polyurethane -- -- 2.00 2192
HB25
TABLE-US-00004 TABLE 3 Data Results for Ballistic-resistant panels
of UHMWPE tape formed with various adhesives at Molding Pressure
3,000 psi and Ballistic Test Results: Adhe- Average Adhesive sive
Adhe- Areal 0.30 Cal Descrip- Weight sive Density FSP V.sub.50 tion
Adhesive ID (gsm) (wt %) (psf) (fps) A1 Polyamide 5.93 10.4 1.94
1915 C1 Ethylene Vinyl 5.93 10.4 1.96 1963 Acetate Copolymer B1
Polyolefin 5.93 10.4 1.96 2014 B1 Polyolefin 3.10 5.7 2.02 1970 F1
Polystyrene- 7.40 12.6 2.03 2242 Isoprene Copolymer F1 Polystyrene-
5.70 10.0 2.02 2136 Isoprene Copolymer Dyneema Polystyrene- -- --
2.00 2541 HB2 Isoprene Dyneema Polyurethane -- -- 2.00 2386
HB25
[0037] A summary of the data suggest that the 3000 psi
ballistic-resistant panels molded with adhesives A1, B1, and C1
rated slightly higher for ballistic performance than did the 150
psi panels. Adhesives B1 and C1 were essentially equal in
performance. The V.sub.50 results suggest that all of the test
panels were acceptable for ballistic resistance of .30 caliber
fragment simulated projectiles.
[0038] Ballistic-resistant panels were then prepared to test the
performance of Tensylon tape versus conventional high modulus
fibers. Dyneema HB25 cross-plied fibers embedded in resin,
available from DSM Dyneema B.V., Urmond, the Netherlands, were
formed into a 2.0-psf panel. A panel formed of 100% HB25 as the
high modulus component was used as a control sample or baseline. A
nominal 2.0-psf panels was also formed of 100% high modulus
Tensylon tape. Various other combinations of Tensylon tape and HB25
were formed into ballistic-resistant panels to test the ballistic
resistance of panels with various amounts of Tensylon tape in place
of the conventional high modulus component and to also test whether
the Tensylon tape was more effective in various configurations,
such as 1) alternating sheets of Tensylon tape and conventional
high modulus component, 2) Tensylon tape as a strike-face at the
front of the ballistic-resistant panel, and 3) Tensylon tape as the
backing material with conventional high modulus component forming
the strike face, and 4) varying the ratio of Tensylon tape to
conventional high modulus component. Several of these variations
were molded into panels at 150 psi and 250.degree. F. as shown in
Table 4 below, and several molded into panels at 150 psi and
210.degree. F. as shown in Table 5. The ballistic-resistant panels
were tested with .30 caliber FSP rounds and the V.sub.50 results
recorded.
[0039] Table 4 includes, left to right in columns 1 to 7:1) the
high modulus composition, 2) the baseline V.sub.50 test result for
panels formed of one high modulus component, 3) the V.sub.50 test
result for panels formed with a Tensylon strike-face, 4) the
V.sub.50 test result for panels formed with HB25 as the
strike-face, 5) the calculated V.sub.50, and 6) the delta V.sub.50
which is the difference between the calculated V.sub.50 and the
actual V.sub.50 recorded in columns 3, 4, or 5. The calculated
V.sub.50 is determined by the Rule of Mixtures wherein the property
of a composite is proportional to the volume fractions of the
materials in the composite, thus the calculated V.sub.50 for a
50/50 ratio of Tensylon C and HB25 is V.sub.50=0.5 (1650)+0.5
(2250) or V.sub.50 (calculated)=1950. The Tensylon C (Ten C) and
Tensylon A (Ten A) were panels molded with different adhesives.
[0040] Thus, if the Delta V.sub.50 is within plus or minus 50 fps,
the Rule of Mixtures is a good predictor of the final V.sub.50
value, and there is no effect from the manner in which the separate
high modulus components are combined in the panel. Thus the
V.sub.50 for alternating layers of Tensylon tape and HB25, which is
represented by line 4 of the table, is predicted by the Rule of
Mixtures. However, if the absolute value of the Delta V.sub.50 is
significantly greater than 50 fps for several of the test panels,
it implies that the order in which the high modulus components are
arranged in the ballistic-resistant panel is statistically
significant. Thus, where the Tensylon tape is placed with respect
to front or back in the ballistic-resistant panel has a significant
effect on the ballistic performance of the panel. A Delta V.sub.50
that is greater than +50 fps indicates a higher ballistic
resistance result than expected by the Rule of Mixtures and thus an
advantageous configuration of high modulus components within the
panel. A Delta V.sub.50 that is less than -50 fps indicates a lower
ballistic resistance result than expected by the Rule of Mixtures
and thus an undesirable configuration of high modulus components
within the panel.
[0041] Therefore, it can be concluded from the test results in
Table 4 that the compositions in rows 5 and 10 through 12 are
advantageous for producing a panel with high ballistic resistance.
Column 1 shows the high modulus composition of these panels are 25%
Tensylon/50% HB25/25% Tensylon (panel 5), 25% Tensylon/75% HB25
(panels and 11), and 50% Tensylon/50% HB25 (panel 12). Results
therefore show that a strike-face consisting of high modulus UHMWPE
Tensylon tape improves the performance of ballistic-resistant
panels. In the final ballistic-resistant panel, the adhesive was
less than 20 weight percent of the total weight of the panel.
TABLE-US-00005 TABLE 4 Test Results of 2.0 psf Ballistic-resistant
panels at Molding Pressure 150 psi and 250.degree. F. Temperature:
Base- Calcu- High line Tensylon Tensylon lated Delta Modulus Ratio
0.30 cal. Front Back V.sub.50 V.sub.50 Component (%) V.sub.50 (fps)
V.sub.50 (fps) V.sub.50 (fps) (fps) (fps) HB25 100 2250 -- -- -- --
Tensylon C 100 1650 -- -- -- -- Tensylon A 100 1933 -- -- -- --
TenC/HB25 alt.* 50/50 -- 1965 -- 1950 +15 TenC/HB25/TenC 25/50/25
-- 2211 -- 1950 +261 HB25/TenC/HB25 25/50/25 -- -- 1989 1950 +39
HB25/TenA 50/50 -- -- 1933 2092 -159 HB25/TenC 50/50 -- -- 1750
1950 -200 HB25/TenC 75/25 -- -- 1852 2101 -249 TenC/HB25 25/75 --
2333 -- 2101 +232 TenA/HB25 25/75 -- 2255 -- 2151 +104 TenC/HB25
50/50 -- 2217 -- 1950 +267 TenC/HB25 alt.*--alternating layers of
Tensylon C and HB25.
[0042] Table 5 includes ballistic test results for panels of
various compositions of Tensylon UHMWPE tape and HB25 fibers molded
at 150 psi and 210.degree. F. The ballistic-resistant panels were
tested with .30 caliber FSP rounds and the V.sub.50 velocities
recorded.
TABLE-US-00006 TABLE 5 Test Results of 2.0 psf Ballistic-resistant
panels at Molding Pressure 150 psi and 210.degree. F. Temperature:
Base- Calcu- High line Tensylon Tensylon lated Delta Modulus Ratio
0.30 cal. Front Back V.sub.50 V.sub.50 Component (%) V.sub.50 (fps)
V.sub.50 (fps) V.sub.50 (fps) (fps) (fps) HB25 100 2154 -- -- -- --
Tensylon A 100 1986 -- -- -- -- HB25/TenA 50/50 -- -- 1909 2070
-161 TenA/HB25 50/50 -- 2289 -- 2070 +219 TenA/HB25 25/75 -- 2300
-- 2112 +188
[0043] As reference to Table 5 shows, the ballistic resistance for
the 2.0 psf panels molded at 150 psi and 210.degree. F. was
improved significantly with Tensylon UHMWPE tape used as the strike
face of the panel. The improvement in ballistic resistance with the
addition of Tensylon tape as the strike face therefore occurred
with panels molded at 250.degree. F. (Table 4) as well as at
210.degree. F. (Table 5).
[0044] Table 6 includes ballistic test results for 3.8 nominal psf
ballistic-resistant panels composed of Tensylon UHMWPE tape and
aramid fabric molded with SURLYN.RTM. resin at 150 psi and
250.degree. F. SURLYN.RTM. is an ethylene/methacrylic acid
copolymer available from DuPont Packaging and Industrial Polymers
of Wilmington, Del. The aramid fabric is produced commercially by
Barrday, Inc. under the trade name Barrday Style 1013. The aramid
fabric was composed of 3,000 denier Kevlar.RTM. 29 in fabrics of 14
oz/yd.sup.2 weight. One ply of 1.5-mil CAF film (SURLYN.RTM. resin)
was used between each ply of Tensylon tape. (As a result of aramid
fabric and Tensylon tape weight variances, it was difficult to
match areal densities. The ballistic-resistant panels were tested
with .30 caliber FSP rounds and the V.sub.50 velocities
recorded.
TABLE-US-00007 TABLE 6 Test Results of 3.3 psf Ballistic-resistant
panels at Molding Pressure 150 psi and 250.degree. F. Temperature:
Base- line Calcu- High 0.30 cal. Tensylon Tensylon lated Delta
Modulus Ratio FSP Front Back V.sub.50 V.sub.50 Component (%)
V.sub.50 (fps) V.sub.50 (fps) V.sub.50 (fps) (fps) (fps) Aramid 100
2491 -- -- -- -- Tens/ 50/50 2320 -- -- 2405 -85 Ara alt.* Tens/Ara
50/50 -- 2632 -- 2405 +227 Ara/Tens 50/50 -- -- 2275 2405 -130
Tens/Ara alt.*--alternating layers of Tensylon and Aramid.
[0045] As shown in Table 6, the test panel with a Tensylon tape
strike face had ballistic resistance of 2632 fps, which was
significantly higher than that predicted by the Rule of
Mixtures.
[0046] Table 7 includes ballistic test results for 3.8 nominal psf
ballistic-resistant panels composed of Tensylon UHMWPE tape and
HB25 and tested with an NIJ Level III M80 ball projectile (U.S.
military designation for 7.62 mm full metal jacketed bullet).
TABLE-US-00008 TABLE 7 Test Results - 3.8 psf Ballistic-resistant
panels, M80 Ball: High Molding Areal Calculated V.sub.50 Delta
Modulus Ratio Pressure Density M80 ball M80 ball V.sub.50 Component
(%) (psi) (psf) V.sub.50 (fps) (fps) (fps) HB25 100 150 4.01 --
2965 -- Tensylon 100 150 4.00 -- 2107 -- Tens/ 50/50 150 3.80 2565
2416 -149 HB25 alt.* Tensylon/ 50/50 150 3.85 2565 2880 +315 HB25
Tensylon/ 25/75 150 3.85 2750 2897 +147 HB25 Tens/HB25
alt.*--alternating layers of Tensylon and HB25.
[0047] As shown in Table 7 for nominal 3.8 psf composite
ballistic-resistant panels, the Tensylon UHMWPE tape had a
beneficial effect when placed as the strike-face of the
ballistic-resistant panel, including a V50 velocity of 2880 fps for
the ballistic-resistant panel in which the Tensylon tape comprised
the strike-face and 50% of the high modulus component and a V50
velocity of 2897 fps for the ballistic-resistant panel in which the
Tensylon tape comprised the strike-face and 25% of the high modulus
component.
[0048] Table 8 includes ballistic test results for a spall liner
for simulated armor with facings of aluminum and High Hardness
Steel (HHS) and various backing compositions including various
weights of HB25 and various compositions including HB25 and
Tensylon tape. All of the armor designs including Tensylon tape as
a high modulus component had positive results for rifle threat
relative to the requirement.
TABLE-US-00009 TABLE 8 Ballistic Data Summary - Spall Liner: Rifle
Frag.** Threat Threat Total Relative Relative Armor Design AD to
Rqmt.* to Rqmt. Facing Backing (psf) (fps) (fps) 1'' 6061 2.5 psf
HB25 27.2 +232 fps Not tested Al/1/4'' HHS 3.0 psf HB25 27.7 -42
Not tested 3.5 psf HB25 28.2 +419 Not tested 1.25 psf Ten/1.25 psf
HB25 27.2 +152 Not tested 1.50 psf Ten/1.50 psf HB25 27.7 +144 Not
tested 1.75 psf Ten/1.75 psf HB25 28.2 +564 +1000 1.5'' 6061 1.30
psf HB25 33.1 +412 Not tested Al/1/4'' HHS 1.25 psf Ten/1.25 psf
HB25 33.1 >+464 Not tested 1.60 psf Ten 33.4 +390 +1639
*Rqmt.--Requirement. **Frag.--Fragmentation
[0049] Table 9 includes ballistic test results for a simulated
spall liner including the following various configurations: 1) a
baseline configuration of 1/4'' Ultra High Hard Steel (UHHS) and
1.1 psf of KEVLAR.RTM. Reinforced Plastic (KRP), 2) baseline plus
25-mm of HB25 spaced 25-mm behind the KRP, 3) baseline plus 25-mm
of high modulus components comprised of 25% Tensylon and 75% HB25
spaced 25-mm behind the KRP, and 4) baseline plus 25-mm of high
modulus components comprised of 50% Tensylon and 50% HB25 spaced
25-mm behind the KRP. Test results included the spall cone angle
measured at layers 1 and 3 and the average number of fragments that
penetrated at layers 1 and 3. The spall cone angle and average
number of fragments through for a spall liner including 25% and 50%
Tensylon tape were similar to those obtained for a spall liner of
100% HB25.
TABLE-US-00010 TABLE 9 Ballistic Data Summary - Simulated Spall
Liner, 20 mm FSP: Spall Cone Average # of Angle (degrees) Fragments
Through Material Layer 1 Layer 3 Layer 1 Layer 3 Baseline
Configuration: 66.44 61.70 214.5 35.0 1/4'' UHHS + 1.1 psf KRP
Baseline with: 51.12 35.04 88.50 11.0 25-mm HB25 spaced 25-mm
behind KRP Baseline with: 56.46 36.75 89.50 10.5 25-mm 25% Tens/75%
HB25 spaced 25-mm behind KRP Baseline with: 52.58 32.57 103.0 9.0
25-mm 50% Tens/50% HB25 spaced 25-mm behind KRP
[0050] In another embodiment, ballistic-resistant panels were
constructed using Tensylon tape as the high modulus component to
determine the effect of molding pressure and temperature on
ballistic resistance. Table 10 includes ballistic test results for
2.0 psf panels comprised of cross-plied layers of 1.62-inch width
Tensylon UHMWPE tape, with a first series of panels molded at 150
psi and at various temperatures and a second series of panels
molded at 500 psi and at various temperatures. The cross-plied
layers of Tensylon UHMWPE tape were interleaved with a low density
polyolefin scrim (Spunfab PO4605) and pressed and bonded at the
various pressures and temperatures recorded in the table. The last
entry in Table 10, Tensylon*, was comprised of layers of 1.62-inch
Tensylon tape woven into a fabric using a basket weave with the
weft arranged at 90.degree. with respect to the warp. The woven
layers were pressed with an 18-micron low density polyethylene film
to form a 2.2 psf ballistic-resistant panel. The
ballistic-resistant panels were tested with .30 caliber FSP rounds
per MIL-P-46593A and the average V.sub.50 velocities recorded.
TABLE-US-00011 TABLE 10 Test Results of 2.0 psf Ballistic-resistant
panels at Molding Pressures 150 psi and 500 psi and at various
Temperatures: Molding Average High Modulus Pressure Temperature
V.sub.50 Component (psi) (degrees F.) (fps) Tensylon B1 150 200
1601 Tensylon B1 150 210 1702 Tensylon B1 150 220 1630 Tensylon B1
150 230 1689 Tensylon B1 150 240 1611 Tensylon B1 150 250 1634
Tensylon B1 150 260 1577 Tensylon B1 150 270 1543 Tensylon B1 150
280 1551 Tensylon B1 500 180 1790 Tensylon B1 500 190 1717 Tensylon
B1 500 200 1692 Tensylon B1 500 210 1647 Tensylon B1 500 220 1588
Tensylon B1 500 230 1593 Tensylon B1 500 240 1566 Tensylon B1 500
250 1649 Tensylon B1 500 260 1703 Tensylon* 500 250 1826 *2.2 psf
panel formed of Tensylon 0/90 weave with 1'' tape.
[0051] As shown in FIG. 6, the resultant average V.sub.50 values
for the Tensylon B1 panels of Table 10 were plotted versus
temperature and a regression line fitted each series of data
points. The ballistic resistance of the panels generally increased
as the molding temperature was decreased.
[0052] Although the embodiments of ballistic-resistant panels
describe above were prepared at specific parameters, other
variations of processing conditions are possible without departing
from the scope of the invention. For example, although the Tensylon
UHMWPE tape in adjacent layers of the ballistic-resistant panel
were oriented at 0.degree. and 90.degree. respectively, other
orientations are possible, such as 0.degree. and 45.degree. in
adjacent layers, or 0.degree., 45.degree., and 90.degree. for each
three successive layers. Preferably the direction of orientation of
the tape in each of the interleaved layers of non-fibrous ultra
high molecular weight polyethylene tape is at an angle of at least
30 degrees with respect to the direction of orientation of the tape
in an adjacent layer. Although the specific molding temperatures
tested herein were between 180 and 280.degree. F., it is believed
that molding temperatures between 150.degree. F. and 300.degree. F.
are acceptable for forming a ballistic-resistant panel according to
the present invention. Although specific molding pressures of 150,
500, and 3000 psi were tested, it is believed that molding
pressures between 100 and 4000 psi are acceptable for forming
ballistic-resistant panels according to the present invention.
[0053] Although in one embodiment herein the Tensylon tape was
woven into a fabric using a basket weave, it is within the scope of
the present invention to form the Tensylon tape into fabric using
any fabric weave, such as plain weave, twill weave, satin weave,
and the like.
[0054] Having thus described the invention with reference to a
preferred embodiment, it is to be understood that the invention is
not so limited by the description herein but is defined as follows
by the appended claims.
* * * * *