Process for making flexible polyurethane foams

摘要

Process for preparing a flexible polyurethane foam by reacting a polyisocyanate and two different polyols under foam forming conditions so as to prepare a rigid foam, by crushing the rigid foam so obtained and by subjecting the flexible foam so obtained to a heat treatment. Flexible foams are obtained which do not show a major glass transition temperature between -100° C. and +25° C.