Composite and method for making

Abstract

A composite includes a first layer of a first fluoropolymer; a second layer of at least one ply of a reinforcing fabric overlying the first layer; and a third layer of a second fluoropolymer overlying the second layer opposite to the first layer, wherein the first layer, the third layer, or combination thereof have an outer surface that is defect free; wherein the composite has a continuous length of at least about 3 meters. Embodiments of such composites can find applications, for example, as processing aids for an electronic device, a food, a polymer, insulating an electrical device, or heat sealing a polymer.

What is claimed is: 
     
         1 . A method of manufacturing a composite, the method comprising:
 providing a stack having a continuous length of at least 3 meters, wherein the stack comprises a first layer of a first fluoropolymer, a second layer of at least one ply of a reinforcing fabric onto the first layer, and a third layer of a second fluoropolymer onto the second layer opposite to the first layer;   laminating the stack at a pressure of about 0.5 MPa to about 6 MPa simultaneously with heat at a temperature of about 200° C. to about 400° C. through two substantially parallel surfaces for at least 10 seconds to form the composite; wherein the composite is free of a void on an outer surface of the first layer and on an outer surface of the third layer.   
     
     
         2 . The method according to  claim 1 , wherein providing the stack comprises casting, skiving, or extruding the first layer, the third layer, or a combination thereof. 
     
     
         3 . The method according to  claim 1 , wherein providing the stack comprises dry powder coating the first layer, the third layer, or a combination thereof. 
     
     
         4 . The method according to  claim 1 , further comprising sintering the first layer, the third layer, or a combination thereof. 
     
     
         5 . The method according to  claim 1 , further comprising cooling the stack to a second temperature at a cooling rate of about 5° C./s to about 20° C./s after the stack is laminated. 
     
     
         6 . The method according to  claim 1 , further including surface treating the reinforcing fabric to enhance adhesion of the first layer, the third layer, or a combination thereof to the second layer. 
     
     
         7 . The method according to  claim 1 , wherein the first layer and the second layer are directly in contact, the second layer and the third layer are directly in contact, or a combination thereof. 
     
     
         8 . The method according to  claim 7 , wherein the composite has at least a cohesive strength between the first layer, the second layer, and the third layer. 
     
     
         9 . The method according to  claim 1 , wherein the composite has an initial wear resistance quantified as a less than 10% change in coefficient of friction after being subject to 200 revolutions in a pin-on-disk wear test. 
     
     
         10 . The method according to  claim 1 , wherein the composite has an abrasion resistance of less than 1% mass loss after 100 cycles or less than 1% exposure of fabric knuckles. 
     
     
         11 . The method according to  claim 1 , wherein the composite has a water vapor transmission rate of less than about 0.05 oz/m 2 -day for the composite having a total thickness of 10 mil. 
     
     
         12 . The method according to  claim 1 , wherein the first layer, the third layer, or a combination thereof has an outer surface that has less than 50 surface cracks per 0.5 square inch and a maximum of 3 surface protrusions of 0.1 mm in height dimension per 100 square. 
     
     
         13 . The method according to  claim 1 , wherein the composite has a dielectric strength of at least 1200 volts/mil for the composite having a total thickness of 10 mil. 
     
     
         14 . The method according to  claim 1 , wherein the composite has a flex life cycle of at least 5000 cycles as measured by an MIT flex test. 
     
     
         15 . The method according to  claim 1 , wherein the first fluoropolymer, the second fluoropolymer, or a combination thereof comprises a non-melt processible fluoropolymer comprising polytetrafluoroethylene (PTFE), modified polytetrafluoroethylene (mPTFE), or a combination thereof. 
     
     
         16 . The method according to  claim 15 , wherein the first fluoropolymer, the second fluoropolymer, or a combination thereof further comprises a melt-processible fluoropolymer at an amount of not greater than about 10 weight %, based on the total weight of the first fluoropolymer and the second fluoropolymer. 
     
     
         17 . The method according to  claim 1 , wherein the first fluoropolymer, the second fluoropolymer, or a combination thereof further comprises a filler. 
     
     
         18 . The method according to  claim 17 , wherein the filler comprises fibers, glass fibers, carbon fibers, aramids, inorganic materials, ceramic materials, carbon, glass, graphite, aluminum oxide, molybdenum sulfide, bronze, silicon carbide, woven fabric, powder, sphere, thermoplastic material, polyimide (PI), polyamidimide (PAI), polyethersulfone (PES), polyphenylene sulfone (PPSO2), liquid crystal polymers (LCP), polyetherketone (PEK), aromatic polyesters (Ekonol), mineral materials, wollastonite, barium sulfate, or combination thereof. 
     
     
         19 . The method according to  claim 1 , wherein the reinforcing fabric comprises at least one yarn in a warp direction, in a weft direction, or a combination thereof, the at least one yarn comprising a fluoropolymer fiber. 
     
     
         20 . The method according to  claim 1 , wherein the first layer has a same thickness as a thickness of the third layer.