Patent ID: 8293807
Filing Date: 2012-10-23
Classification: C08G

Abstract:
1. A process for producing rigid polyurethane foams, comprising: reacting a) at least one polyisocyanate with b) compounds having at least two hydrogen atoms which are reactive toward isocyanate groups in the presence of c) blowing agents and a foam stabilizer, wherein the reaction is conducted in the presence of a catalyst, the compounds having at least two hydrogens which are reactive toward isocyanate groups, comprise: 10 to 25% by weight of at least one graft polyol b1); 25 to 65% by weight of a sucrose-initiated polyether alcohol b2); and 10 to 40% by weight of a polyether alcohol b3) obtained by alkoxylation of a vicinal toluene diamine or ethylene diamine; wherein the at least one graft polyol b1), comprises: acrylonitrile and styrene in a weight ratio of acrylonitrile:styrene of from greater than 1:1 to 4:1; a carrier polyether alcohol b1i) having: a functionality of from 2 to 4, a hydroxyl number in the range from 100 to 250 mg KOH/g, and at least one compound b1ii) which has at least one olefinic double bond and is miscible with the carrier polyether alcohol b1i).