Thermoplastics tubes or solid objects of various shapes - produced by reshaping semi-finished prod. using rotation heat and pressure

摘要

A method of making tubes, solid objects and hollow objects of any desired form consists of reshaping thermoplastics semi-finished prods. and cylindrical prods. while they are in the thermoplastic condition by rotation in conjunction with pressure and heat. Used esp. for the prodn. of pipes and other hollow articles possessing a larger particle crystallinity, and for the prodn. of pipes of differing diameters along their lengths. Process is also for producing high-strength plastics screws and bolts. The shape conversion may be carried out without rotation using only pressure and heat. Alternatively, only rotation and pressure, without external supply of heat, may be used.