Patent ID: 6040349
Filing Date: 2000-03-21
Classification: C08G,C08J

Abstract:
A process for producing rigid polyurethane foams having reduced density comprising reactinga) organic and/or modified organic polyisocyanates withb) at least one higher-molecular-weight compound having at least two reactive hydrogen atoms and, optionally,c) low-molecular-weight chain extenders and/or crosslinkersin the presence ofd) blowing agente) catalysts and, optionally,f) other auxiliaries and/or additives,wherein the blowing agent (d) comprises a mixture of cyclopentane, at least one compound which is homogeneously miscible with cyclopentane selected from the group consisting of alkanes and alkenes having 3 or 4 carbon atoms in the molecule, and carbon dioxide produced from water and isocyanate, and wherein the higher-molecular-weight compound (b) having at least two reactive hydrogen atoms comprise polyethers which contain aromatics and nitrogen.