ELEMENTI TUBOLARI CON NERVATURE O PARETI INTERNE REALIZZATI IN PET, STRUTTURE RESISTENTI REALIZZATE CON TALI ELEMENTI E FILIERA PER

摘要

Method and die for extruding tubes of thermoplastic material, in particular PET, whereby the outer surface of a PET tube while being extruded and still in the plastic state is suddenly and rapidly cooled in correspondance with a narrow terminal region of the die such as to cause hardening of an external surface layer of the tube, the die surface in correspondence with said limited terminal region widening outwards.