Process for the preparation of rigid to semirigid polyurethane foams with an increased open-cell content and reduced shrinkage

摘要

Method for the prepn. of tough PU foams with increased open cell content and reduced shrinkage comprises reacting: (a) (modified) organic polyisocyanates; with (b) at least one high mol. wt. cpd. contg. at least two reactive hydrogen atoms; and pt. (c) lower mol. wt. chain extending- and/or crosslinking agents, comprising at least one polyol recyclate prepd. by glycolysis of (polyurea-)polyurethanes using glycide ethers; in the presence of (d) catalysts; (e) opt. propellants; and (f) opt. auxiliary agents and/or additives. No special cell openers are used in the prepn. process. The foams prepd. by this method are also claimed.