Polymeric integral net

Abstract

The present invention provides an integral net having a lattice of polymeric material defined by holes traversing the integral net from one surface to the other. The present invention also provides a method for producing an embossed sheet of polymeric material by first contacting a billet of polymeric material with an embossing tool having a plurality of protrusions whereby the embossing tool impresses indentations into the billet to a given depth. Subsequently, the method involves skiving the embossed billet. By this method, an embossed sheet of the polymeric material is removed from the billet, which embossed sheet can be an integral net.

What is claimed is:  
     
         1 . A nonwoven, nonextruded, single-layer integral net comprising a lattice of polymeric material, having two opposing faces and at least one hole traversing the net from one face to the other face.  
     
     
         2 . The-net of    claim 1   , wherein said polymeric material is thermoplastic material.  
     
     
         3 . The net of    claim 2   , wherein said thermoplastic material is a fluoropolymer.  
     
     
         4 . The net of    claim 1   , wherein said polymeric material is polytetrafluoroethylene-co-perfluoro (alkylvinyl ether).  
     
     
         5 . The net of    claim 1   , wherein said polymeric material is ultra high molecular weight polyethylene.  
     
     
         6 . The net of    claim 1   , wherein said polymeric material is polytetrafluoroethylene.  
     
     
         7 . The net of    claim 1   , which consists essentially of said polymeric material.  
     
     
         8 . The net of    claim 2   , which consists essentially of said polymeric material.  
     
     
         9 . The net of    claim 3   , which consists essentially of said polymeric material.  
     
     
         10 . The net of    claim 7   , which consists of said polymeric material.  
     
     
         11 . The net of    claim 7   , wherein said lattice is substantially free of extractable matter.  
     
     
         12 . The net of    claim 1   , wherein a face of said lattice comprises punctate depressions into a surface of said lattice.  
     
     
         13 . The net of    claim 12   , wherein a depression forms a furrow between two adjacent holes of said net.  
     
     
         14 . The net of    claim 1   , wherein said lattice has not been stretched.  
     
     
         15 . A filtration apparatus comprises a housing, a process fluid inlet arranged to direct process fluid into said housing, a permeate outlet arranged to direct permeate from said housing, at least one separation element disposed within said housing, and an integral net of    claim 1   , one surface of which communicates with said process fluid inlet, and another surface of which communicates with said permeate outlet.  
     
     
         16 . A method of separating particulate matter from a process fluid employing the filtration apparatus of    claim 15   .  
     
     
         17 . A method for producing an embossed sheet from an embossed billet of polymeric material having a surface comprising one or more indentations, said method comprising skiving said billet, whereby an embossed sheet comprising a lattice is removed from said billet.  
     
     
         18 . The method of    claim 17   , wherein said polymeric material is thermoplastic material.  
     
     
         19 . The method of    claim 18   , wherein said thermoplastic material is a fluoropolymer.  
     
     
         20 . The method of    claim 17   , wherein said polymeric material is polytetrafluoroethylene-coperfluoro(alkylvinyl ether).  
     
     
         21 . The method of    claim 17   , wherein said polymeric material is ultra high molecular weight polyethylene.  
     
     
         22 . The method of    claim 17   , wherein said polymeric material is polytetrafluoroethylene.  
     
     
         23 . The method of    claim 17   , wherein said billet consists essentially of said polymeric material.  
     
     
         24 . The method of    claim 18   , wherein said billet consists essentially of said polymeric material.  
     
     
         25 . The method of    claim 19   , wherein said billet consists essentially of said polymeric material.  
     
     
         26 . The method of    claim 23   , wherein said billet consists of said polymeric material.  
     
     
         27 . The method of    claim 23   , wherein said billet is substantially free of extractable matter.  
     
     
         28 . The method of    claim 17   , wherein said embossed billet is cylindrical in shape and is skived while axially rotated.  
     
     
         29 . The method of    claim 17   , wherein said embossed sheet is of substantially uniform thickness.  
     
     
         30 . The method of    claim 17   , which method further comprises heat-treating said embossed sheet of said polymeric material.  
     
     
         31 . The method of    claim 17   , which method further comprises rendering hydrophilic a surface of said embossed sheet.  
     
     
         32 . The method of    claim 17   , wherein said indentations are grove-like, whereby said embossed sheet forms filaments.  
     
     
         33 . The method of    claim 17   , wherein said billet is skived at a depth shallower than the depth of said indentations, whereby said sheet is an integral net.  
     
     
         34 . The method of    claim 17   , wherein said billet is skived at a depth deeper than the depth of said indentations.  
     
     
         35 . The method of    claim 17   , which method further comprises contacting said embossed sheet with a second embossing tool, whereby punctate depressions are imprinted into a surface of said embossed sheet.  
     
     
         36 . The method of    claim 35   , wherein said punctate depressions are furrows between two adjacent indentations of said embossed sheet.  
     
     
         37 . The method of    claim 17   , wherein said indentations are formed by impressing one or more protrusions of an embossing tool into said surface of polymeric material.  
     
     
         38 . The method of    claim 37   , wherein said embossing tool comprises a plurality of protrusions.  
     
     
         39 . The method of    claim 38   , wherein said protrusions are tapered.  
     
     
         40 . The method of    claim 39   , wherein said protrusions have an included angle greater than about 5° and less than about 180°.  
     
     
         41 . The method of    claim 37   , which method further comprises heating said surface or said billet prior to contacting said billet with said embossing tool.  
     
     
         42 . The method of    claim 37   , in which said embossing tool comprises a heating element such that said embossing tool heats said surface of said billet.