Patent ID: 6765035
Filing Date: 2004-07-20
Classification: C08J

Abstract:
Process for preparing a rigid foam by reacting a polyisocyanate (1), an isocyanate-reactive compound (2), said compound (2) having an average equivalent weight of at most 374 and an average number of isocyanate-reactive hydrogen atoms of from 2 to 8, an isocyanate-reactive compound (3), said compound (3) having an average equivalent weight of more than 374 and an average number of isocyanate-reactive hydrogen atoms of from 2 to 6 and water in the presence of a catalyst and in the presence of a fire retardant wherein the fire retardant is a combination of 1) expandable graphite and 2) phosphorous-containing compounds of formula: wherein X, Y and Z are independently selected from the groups â€”R and â€”ORâ€² wherein R is an alkyl, aryl or aralkyl group having 1-12 and preferably 1-10 carbon atoms, and Râ€² is an aryl or aralkyl group having 6-12 and preferably 6-10 carbon atoms and wherein the phosphorous-containing compounds are selected from triphenylphosphine oxide, triphenylphosphate, triphenylphosphonate and compounds having one or more, and preferably one, alkyl group(s) having 1-6 carbon atoms, attached to one or more of the aromatic rings of these triphenylphosphate, -phosphonate and -phosphine oxide.