Fabrics with strain-responsive viscous liquid polymers
View Patent ↗A penetration resistant article with an area density less than 1.5 lb/ft 2 made of a plurality of fibrous fabric layers that have applied thereto about 1 to 8 percent by weight of a polymer having a glass transition temperature in the range of minus 40 to about 0° C. and a zero shear melt viscosity 2×10 6 to about 10 13 poise at 20° C.
1. A penetration resistant article comprising a plurality of fabric layers, at least one layer comprising;
fibers and a liquid polymer, selected from the group consisting ethylene/methyl acrylate, polyvinyl propionate, poly (hexyl methacrylate), and mixtures thereof, the polymer having;
a glass transition temperature in the range of minus 40 to about 0° C., and
a zero shear melt viscosity 2×10 6 to about 10 13 poise at 20° C. wherein the article has an area density less than 1.5 lb/ft 2 and the polymer is 1 to about 8 percent by weight of the fabric.
2. The article of claim 1 wherein the fibers of the fabric layers are selected from the group consisting of aromatic polyamide, polyolefin, polybenzoxazole, polybenzothiazole, poly{2,6-diimidazo[4,5-b4′, 5′-e]pyridinylene-1,4(2,5-dihydroxy)phenylene}, polyareneazoles, polypyridazoles, polypyridobisimidazoles, and mixtures thereof.
3. The article of claim 1 , having 10 to 60 layers.
4. The article of claim 1 , wherein the polymer is coated onto the fabric.
5. The article of claim 1 , wherein the polymer is at least partially impregnated into the fabric structure.
6. The article of claim 4 , wherein the polymer is ethylene/methyl acrylate.
7. The article of claim 4 wherein at least one coated layer is self-healing and exhibits at least 50% recovery In peak force associated with in-plane straining of the fabric.
8. The article of claim 1 , wherein the back face deformation is less than 44 mm when tested in compliance with NIJ standard 0101.04.
9. The penetration resistant article of claim 6 , wherein the polymer comprises about 1 to about 8 percent by weight of the fabric.
10. A penetration resistant article comprising a plurality of fabric layers at least one layer comprising fibers and a liquid polymer selected from the group consisting of ethylene-methyl acrylate, polyvinyl propionate, poly(hexyl methacrylate), and mixtures thereof, the polymer having a glass transition temperature in the range of minus 40 to about 0° C., and a zero shear melt viscosity 2×10 6 to about 10 13 poise at 20° C. that is 8% by weight or less of the layer, wherein the article has at least a 10% improvement in back face deformation compared to an identically constructed article not having the polymer when tested in compliance with NIJ standard 0101.04.
11. The penetration resistant article of claim 1 , wherein the fabric is woven.
12. The penetration resistant article of claim 10 , wherein the liquid polymer is ethylene-methyl acrylate.