Patent ID: 6316513
Filing Date: 2001-11-13
Classification: C08G

Abstract:
A process for the production of rigid polyurethane foams having low thermal conductivity comprising reactingA) a polyol component comprising:(1) at least one polyester polyol having a molecular weight of from 100 to 30,000 g/mol and containing at least two isocyanate-reactive hydrogen atoms;(2) at least one polyether polyol having a molecular weight of from 150 to 12,500 g/mol and containing at least two isocyanate-reactive hydrogen atoms and at least one tertiary nitrogen atom, and being prepared by the polyaddition of one or more alkylene oxides onto at least one starter compound, wherein the starter compound comprises ammonia, or a compound containing at least one primary, secondary or tertiary amino group;(3) at least one polyether polyol having a molecular weight of from 150 to 12,500 g/mol and containing at least two isocyanate-reactive hydrogen atoms, and being prepared by the polyaddition of one or more alkylene oxides onto at least one starter compound, wherein the starter compound comprises water or a polyhydric alcohol;(4) at least one catalyst;(5) water(6) at least one blowing agent selected from the group consisting of n-butane, isobutane, isopentane, cyclopentane, 2,2-dimethylbutane, cyclohexane, and mixtures thereof; and, optionally(7) auxiliary substances and/or additives; withB) an organic polyisocyanate having an NCO group content of from 20 to 48% by weight, wherein said polyisocyanate is optionally modified.