Fast-curve polyurethane sealant composition containing silylsubstituted piperazine accelerators

Claim 1

A one-component, moisture-curable sealant composition comprising a mixture of (a) a silane-terminated polyurethane polymer of the formula wherein R is lower alkyl of from 1 to 6 carbon atoms; R¹ is a divalent bridging radical selected from the group consisting of a divalent hydrocarbon radical, a divalent hydrocarbon ether radical, and a divalent hydrocarbon amino radical; A is selected from the group consisting of -S- and -NR²- where R² is hydrogen or alkyl of from one to six carbon atoms; (b) from 0.2 to 1.0 parts by weight of an aminosilane per 100 parts by weight of said polyurethane polymer, said aminosilane having the structure wherein x is an integer of from one to three; R3 and R⁴ may be the same or different and are selected from alkyl of from one to four carbon atoms; R⁵ is alkyl of from one to four carbon atoms or alkoxyl of from one to four carbon atoms; R⁶ is hydrogen or -(CH₂) y NHR⁷ wherein R⁷ is hydrogen or - (CH₂) z NH₂ and y and z may be the same or different and are integers of from one to three; (c) from 0.2 to 1.0 parts by weight of an accelerator per 100 parts by weight of said polyurethane polymer, said accelerator selected from the group consisting of compounds or mixtures thereof having the structure where w is an integer of from one to five, R⁸, is hydrogen or where a is an integer of from one to four, b is zero or an integer of from one to four, B is a direct bond or is a divalent hydrocarbaryl radical or a divalent cyclohydrocarbyl radical, and R³, R⁴, and R⁵ are as previously defined, R⁹ and R¹⁰ are independently hydrogen, alkyl of from one to five carbon atoms, or where a, b, B, R³, R⁴, and R⁵, are as defined above, with the proviso that at least one of R⁸, R⁹ and R¹⁰ must be