Layered Tube for Improved Kink Resistance

Abstract

A catheter shaft is produced by forming a first polymeric layer onto a flexible inner core while maintaining the inner core in a solid state, and solidifying the first polymeric layer, wherein the solidified first polymeric layer fails to bond with the inner core and is slidable thereon upon flexion of the shaft. A second polymeric layer may be formed over the first polymeric layer, and is slidable thereon when the shaft bends.

1 . A method of making a catheter shaft, comprising the steps of:
 forming a first polymeric layer onto a flexible inner core while maintaining the inner core in a solid state; and   solidifying the first polymeric layer, in which the solidified first polymeric layer fails to bond with the inner core and is slidable thereon upon flexion of the inner core.   
     
     
         2 . The method according to  claim 1 , in which forming a first polymeric layer is performed by extruding. 
     
     
         3 . The method according to  claim 1 , in which forming a first polymeric layer is performed by film casting. 
     
     
         4 . The method according to  claim 1 , further comprising the steps of:
 forming a second polymeric layer onto the solidified polymeric first layer; and   solidifying the second polymeric layer, in which the solidified second polymeric layer fails to bond with the solidified first polymeric layer and is slidable thereon upon flexion of the inner core.   
     
     
         5 . The method according to  claim 4 , in which forming a second polymeric layer is performed by extruding. 
     
     
         6 . The method according to  claim 4 , in which forming a second polymeric layer is performed by film casting. 
     
     
         7 . The method according to  claim 4 , in which a kinetic coefficient of friction between the solidified first polymeric layer and the solidified second polymeric layer does not exceed 0.5. 
     
     
         8 . The method according to  claim 4 , in which the solidified first polymeric layer and the solidified second polymeric layer are composed of identical materials. 
     
     
         9 . The method according to  claim 8 , in which the solidified first polymeric layer and the solidified second polymeric layer are composed of polyimide. 
     
     
         10 . The method according to  claim 4  in which the solidified first polymeric layer and the solidified second polymeric layer are composed of different materials. 
     
     
         11 . The method according to  claim 10 , in which one of the solidified first polymeric layer and the solidified second polymeric layer is ultra-high-molecular-weight polyethylene and another of the solidified first polymeric layer and the solidified second polymeric layer is polyether block amide. 
     
     
         12 . The method according to  claim 1 , in which the inner core comprises a metallic braid.