Polytetrafluoroethylene tubing and extruder for the production thereof

摘要

In an extruder for producing a polytetrafluoroethylene tube having a minimum thickness deviation by extruding a polytetrafluoroethylene paste through an annular portion formed by a core pin (30) and a die orifice (50) around it, the core pin comprises a mandrel connection end (34) which is connected to a mandrel and a die orifice outlet end (36) which is located at a die orifice outlet end, and the core pin has between the ends a portion of which cross-section perpendicular to an axial direction of the core pin has a smaller area than that of a cross-section of each end of the core pin. By using the extruder, the tube having a thickness deviation of not larger than 15% can be obtained.