Fast-cure polyurethane sealant composition containing silyl-substituted piperazine accelerators

Claim 1

A one-component, moisture-curable sealant composition comprising a mixture of (a) a silane-terminated polyurethane polymer of the formula ##STR14## wherein R is lower alkyl of from 1 to 6 carbon atoms; R 1 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 --NR 2 -- where R 2 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 silane-terminated polyurethane polymer, said aminosilane having the structure ##STR15## wherein x is an integer of from one to three; R 3 and R 4 may be the same or different and are selected from alkyl of from one to four carbon atoms; R 5 is alkyl of from one to four carbon atoms or alkoxyl of from one to four carbon atoms; R 6 is hydrogen or --(CH 2 ) y NHR 7 wherein R 7 is hydrogen or --(CH 2 ) y NH 2 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 silane-terminated polyurethane polymer, said accelerator selected from the group consisting of compounds or mixtures thereof having the structure ##STR16## where w is an integer of from one to five, R 8 , is hydrogen or ##STR17## 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 R 3 , R 4 , and R 5 are as previously defined, R 9 and R 10 are independently hydrogen, alkyl of from one to five carbon atoms, or ##STR18## where a, b, B, R 3 , R 4 , and R 5 , are as defined above, with the proviso that at least one of R 8 , R 9 and R 10 must be ##STR19##