Process for Fabricating Polymeric Articles
A process for the production of a polymeric article directed to (a)forming apply having successive layers, namely, (i) a first layer made up of strands of an oriented polymer material; (ii)a second layer of a polymeric material; (iii)a third layer made up of strands of an oriented polymeric material, wherein the second layer has a lower peak melting temperature that of the first and third layers; (b)subjecting the ply to conditions of time, temperature, and pressure sufficient to melt a proportion of the firsts layer to melt the second layer entirely, and to melt a proportion of the third layer, and to compact the ply; and (c)cooling the compacted ply. The resultant articles have good mechanical properties yet may be made at a lower compaction temperature than articles not employing the second layer, leading to a more controllable manufacturing process.
1 . A polymeric article comprising:
a ply having a plurality of layers such that at least one of the plurality of layers is not oriented;
at least one of the plurality of layers has a thickness of less than or equal to 1 mm; and
at least one of the plurality of layers comprises a polymeric material of polyethylene, polypropylene, polyoxymethylene, polyester, or a homopolymer, copolymer or terpolymer thereof.
2 . The polymeric article of claim 1 , wherein at least one of the plurality of layers is biaxially oriented.
3 . The polymeric article of claim 1 , wherein at least one of the plurality of layers is uniaxially oriented.
4 . The polymeric article of claim 1 , wherein said ply has from 2 to 40 layers.
5 . The polymeric article of claim 1 , wherein at least one of the plurality of layers is a non-woven web.
6 . The polymeric article of claim 1 , wherein at least one of the layers is formed into a fabric by knitting or weaving.
7 . The polymeric article of claim 1 , comprising a plurality of interleaved polypropylene film layers in combination with woven polypropylene tapes;
8 . The polymeric article of claim 7 wherein the article has a molecular weight within 5% of 360,000.
9 . The polymeric article of claim 7 , wherein said article has a density within 5% of 910 kg/m 3 .
10 . The polymeric article of claim 7 , wherein said article has a thickness after extrusion within 5% of 15 μm.
11 . A polymeric article comprising:
an oriented layer laid onto an initial polymeric material such that the oriented layer is a polyethylene, polypropylene, polyoxymethylene or polyester, including as homopolymer, copolymer or terpolymer, and/or blends mixtures thereof; a thickness of said initial polymeric material exceeds that of the oriented layer; and the oriented layer has a oriented layer peak temperature, and the polymeric material has a polymeric material peak temperature, where the oriented layer peak temperature is lower than the polymeric material peak temperature.
12 . The polymeric article of claim 8 , wherein said oriented layer peak temperature is at least 5° C. lower than the polymeric material peak temperature.
13 . The polymeric article of claim 8 , further comprising an additional layer of polymeric material.
14 . The polymeric article of claim 10 , wherein said additional layer of polymeric material and said initial layer have a thickness that together is at least five times more than that of said oriented layer.
15 . The polymeric article of claim 8 , wherein said thickness of said initial polymeric layer exceeds 50 μm.
16 . The polymeric article of claim 8 , wherein said oriented layer is biaxially oriented.
17 . The polymeric article of claim 8 , wherein said oriented layer is comprised of a plurality of film layers.
18 . A method of using a pressure process for a polymeric article comprising:
providing at least two layers of a woven material;
applying an initial pressure in a hot press to said layers of said woven material while said polymeric article is heated to a compaction temperature of at least 130° C.;
applying a second pressure to said layers of said woven material higher than said initial pressure; and
cooling said layers.
19 . The method of claim 16 wherein said initial pressure is within 5% of 0.7 Pa.
20 . The method of claim 16 , wherein the method further comprises placing a layer of LDPE film between said at least two layers of said woven material.