Polyurethane prepolymers with reduced functionality having terminal alkoxysilane and OH groups, a method of preparing them and their use

摘要

The present invention relates to polyurethane prepolymer having terminal alkoxysilane and OH groups which is the reaction product of ;A) a polyurethane prepolymer prepared by incomplete reaction of ;i) an aromatic, aliphatic or cycloaliphatic diisocyanate component having an NCO content of 20 to 60% by weight with ;ii) a polyol component comprising a polyoxyalkylene diol having a number average molecular weight of 3000 to 20,000, ;wherein the reaction is stopped after 50 to 90% of the OH groups of component ii) are reacted and 10 to 50% are unreacted, with ;B) a compound having alkoxysilane and amino groups, preferably a compound containing alkoxysilane and aspartate groups. ;The present invention also relates to a process for preparing these polyurethane prepolymers containing terminal alkoxysilane and OH groups and to isocyanate-free, sealants, adhesives, primers and coatings containing these polyurethane prepolymers containing terminal alkoxysilane and OH groups as binders.