process for formschäumen of integralschaum

摘要

A process for the foam moulding of a semirigid structural foam which comprises a skin having a low degree of foaming which has been formed in one piece and a core zone having a high degree of foaming. The process comprises evacuating a mould cavity to a pressure of from 50 to 700 mmHg; injecting the polyurethane material containing a polyol constituent and an isocyanate constituent into the evacuated mould cavity essentially in the absence of a blowing agent, during which air bubbles are introduced into the material by charging with air; and foaming the material with filling of the mould cavity.