MANUFACTURE OF RESIN TUBULAR FORM

摘要

PROBLEM TO BE SOLVED: To manufacture a resin tubular form which shows a high elastic modulus in tension and a lower melt point than that of thermoplastic resin and further, an extremely small decrease in the modulus of elasticity when the form is maintained under temperature conditions above a glass transition temperature for a long time. SOLUTION: The method for manufacturing a resin tubular form is to perform the orientation molding of a hollow work 1 of crystalline thermoplastic resin by pulling it from a clearance between a die 2 and a former 3 with the help of a clamp 5. In this case, the hollow work 1 is oriented under necking effects to be caused by giving a strain which is larger than the yield strain level of the crystalline thermoplastic resin at its working temperature and smaller than the fracture strain level of the resin at its working temperature to the hollow work 1 in its tensile direction and also its peripheral direction. Thus the thickness is reduced 25% or less compared to the initial thickness.