Patent ID: 7109285

Claim:
A process for preparing phenolically blocked polyurethane prepolymers, comprising reacting a) one or more diisocyanates or polyisocyanates with b) at least one isocyanate-reactive compound with a functionality of at least 1.5 to form an NCO-functional polyurethane prepolymer and subsequently blocking the free NCO groups with c) at least one hydrocarbon resin containing phenolic OH groups, d) in the presence of a catalyst which comprises at least one triorganoamine selected from i) compounds of the general formula (I) where R 1 is an optionally branched C 1 –C 30 alkyl radical, X is O, S or the group N-R 1 and n is 0 or 1, and ii) compounds of the general formula (II) NR 2 R 3 R 4 (II) where R 2 is a C 3 –C 30 alkyl, C 3 –C 10 cycloalkyl or C 6 –C 30 aryl radical and/or the radical —(Y) p (CHR 5 ) q NR 6 R 7 , in which q=1 to 5 and R 5, R 6 and R 7 independently of one another are a C 1 –C 30 alkyl radical and R 5 can also be H, and p=0 or 1 and the radical Y is —C(O)O—, —O—, —NH—CO—, —NH—and/or —N(CH 3 )—, and R 3 and R 4 independently of one another are an optionally substituted C 1 –C 30 alkyl, C 3 –C 10 cycloalkyl or C 6 –C 30 aryl radical and/or the radical —(Y) p (CHR 5 ) q NR 6 R 7 , in which q=1 to 5 and R 5 , R 6 and R 7 independently of one another are a C 1 –C 30 alkyl radical and R 5 can also be H, and p=0 or 1 and the radical Y is —C(O)O—, —O—, —NH—CO—, —NH—and/or —N(CH 3 )—.