Polyterafluoroethylene laminated article

Abstract

To provide a PTFE laminated article having a sufficient adhesive strength and a PTFE backing sheet having a low permeability, in which a specific weight of a PTFE sheet can be maintained high. A specific weight of the PTFE sheet is maintained at 2.175 or more by carrying out thermo-fusing of the PTFE sheet and a film or sheet of heat-meltable resin such as PFA after interposing a layer of PTFE fine particles between them or by carrying out treatment for preventing a rapid temperature lowering after the thermo-fusing without interposing the layer of PTFE fine particles.

1 - 13 . (canceled)  
     
     
         14 . A method of producing a polytetrafluoroethylene laminated article, wherein after a polytetrafluoroethylene sheet and heat-meltable resin film or sheet are directly subjected to thermo-fusing, a rapid temperature lowering is prevented to sufficiently crystallize molten polytetrafluoroethylene.  
     
     
         15 - 30 . (canceled)  
     
     
         31 . The production method of  claim 14 , wherein the laminated article is held within a temperature range of less than a melting point of polytetrafluoroethylene and not less than 300° C. to prevent a rapid temperature lowering.  
     
     
         32 . The production method of  claim 14 , wherein a polytetrafluoroethylene sheet having a specific weight exceeding 2.175 is used as said polytetrafluoroethylene sheet.  
     
     
         33 . The production method of  claim 14 , wherein a heat resistant woven fabric is overlaid on the opposite side of said heat-meltable resin film or sheet, and the heat-meltable resin film or sheet and the heat resistant woven fabric are subjected to thermo-fusing.  
     
     
         34 . The production method of  claim 33 , wherein the heating is carried out from the side of heat resistant woven fabric.  
     
     
         35 . (canceled)  
     
     
         36 . The production method of  claim 14 , wherein a laminated article having a layered structure comprising a polytetrafluoroethylene sheet having an average specific weight of not less than 2.175 and a heat-meltable resin layer is produced by using a polytetrafluoroethylene sheet having a specific weight exceeding 2.175 as said polytetrafluoroethylene sheet.  
     
     
         37 . The production method of  claim 14 , wherein a laminated article having a layered structure obtained by laminating a polytetrafluoroethylene sheet having an average specific weight of not less than 2.175 and a heat resistant woven fabric by interposing a heat-meltable resin layer therebetween is produced by using a polytetrafluoroethylene sheet having a specific weight exceeding 2.175 as said polytetrafluoroethylene sheet.  
     
     
         38 . The production method of  claim 14 , wherein the heating is stopped at a time when an un-molten layer remains in said polytetrafluoroethylene sheet.  
     
     
         39 . The production method of  claim 14 , wherein a polytetrafluoroethylene sheet surface reverse to the laminated surface thereof is heat-treated at a temperature of not less than a melting point of polytetrafluoroethylene before or after said thermo-fusing or at the same time as said thermo-fusing.  
     
     
         40 . The production method of  claim 14 , wherein the laminated article is a backing sheet.