Skived film for covering surface of plug for medical purposes, plug for medical purposes using said film, pre-filled syringe using said plug and method for producing said film

Abstract

Provided is a PTFE skived film capable of exhibiting, with a single layer, sliding properties, barrier properties with regard to a liquid contact surface, and excellent tear resistance during injection molding. This skived film is characterized by being obtained by cutting a polytetrafluoroethylene block or a modified polytetrafluoroethylene block subjected to a thermal fusion treatment under reduced pressure or subjected to a pressurized thermal fusion treatment after being subjected to fusion under reduced pressure.

1 . A skived film for covering a surface of a plug for medical purposes obtained by cutting a polytetrafluoroethylene block or a modified polytetrafluoroethylene block subjected to a thermal fusion treatment under reduced pressure or subjected to a pressurized thermal fusion treatment after being subjected to fusion under reduced pressure. 
     
     
         2 . The skived film for covering a surface of a plug for medical purposes according to  claim 1 , wherein tensile elongation in a machine direction which is a longitudinal direction of the film is greater than or equal to 500%. 
     
     
         3 . A plug for medical purposes having a plug body made of elastomer, wherein the skived film according to  claim 1  is overlaid at least on a sliding part or a liquid contact part of a surface of the plug body. 
     
     
         4 . The plug for medical purposes according to  claim 3 , wherein the plug is a gasket for syringe, an intermediate gasket for syringe, a top cap for syringe, or a laminate plug for vial. 
     
     
         5 . A pre-filled syringe produced by hermetically sealing a syringe barrel charged with a drug liquid with the gasket for syringe or the top cap for syringe according to  claim 4 . 
     
     
         6 . A method for producing a polytetrafluoroethylene film for covering a surface of a plug for medical purposes, comprising the steps of:
 pressure-molding powder material of polytetrafluoroethylene or modified polytetrafluoroethylene charged in a mold to obtain a pressure-molded product having interconnected cells inside;   subjecting the pressure-molded product obtained by the pressure molding to a thermal fusion treatment under reduced pressure; and   cutting the product subjected to the thermal fusion treatment obtained by the thermal fusion treatment to obtain a film.   
     
     
         7 . A method for producing a polytetrafluoroethylene film for covering a surface of a plug for medical purposes, comprising the steps of:
 pressure-molding powder material of polytetrafluoroethylene or modified polytetrafluoroethylene charged in a mold to obtain a pressure-molded product having interconnected cells inside;   subjecting the pressure-molded product to a primary thermal fusion treatment under reduced pressure to block outlets of communication holes of the pressure-molded product to obtain a product subjected to the primary thermal fusion treatment including only closed cells remaining inside;   subjecting the product subjected to the primary thermal fusion treatment to a secondary thermal fusion treatment under increased pressure to obtain a product subjected to the secondary thermal fusion treatment from which the closed cells have disappeared; and   cutting the product subjected to the secondary thermal fusion treatment to obtain a film.   
     
     
         8 . The method for producing a polytetrafluoroethylene film for covering a surface of a plug for medical purposes according to  claim 6 , wherein the powder material of polytetrafluoroethylene or modified polytetrafluoroethylene charged in the mold is pressure molded under reduced pressure to obtain a pressure-molded product. 
     
     
         9 . The method for producing a polytetrafluoroethylene film for covering a surface of a plug for medical purposes according to  claim 6 , wherein pressure reduction is conducted within a pressure range of 0.013 to 133 Pa. 
     
     
         10 . The method for producing a polytetrafluoroethylene film for covering a surface of a plug for medical purposes according to  claim 6 , wherein a thermal fusion treatment temperature is 320 to 400° C. 
     
     
         11 . The method for producing a polytetrafluoroethylene film for covering a surface of a plug for medical purposes according to  claim 7 , wherein a range of pressurization pressure in the secondary thermal fusion treatment is higher than or equal to 0.2 Ma. 
     
     
         12 . The method for producing a polytetrafluoroethylene film for covering a surface of a plug for medical purposes according to  claim 6 , wherein the product subjected to the thermal fusion treatment has a shape which is a rectangular parallelepiped, a cube, a circular column, or a cylinder. 
     
     
         13 . The method for producing a polytetrafluoroethylene film for covering a surface of a plug for medical purposes according to  claim 6 , wherein the film produced by cutting the product subjected to the thermal fusion treatment has a thickness ranging from 20 to 150 μm.