Moisture curable polyisobutylenes

Claim 1

A moisture curable composition comprising an organosiloxy-terminated isobutylene oligomer exhibiting a number average molecular weight of from 1,000 to 100,000, wherein the terminal units of said oligomer are at least 95 percent of the non-terminal repeating units of said oligomer are -C(CH₃)₂CH₂-, and any remaining repeating units other than the residue of the initiator-chain transfer agent used to polymerize the isobutylene are derived from ethylenically unsaturated hydrocarbons that are copolymerizable with isobutylene, the R substituents represent identical or different monovalent hydrocarbon radicals or halogenated monovalent hydrocarbon radicals, R′ represents an alkylene radical containing from 2 to 10 carbon atoms, X represents a hydrolyzable group that is bonded to silicon by means of an oxygen atom or a nitrogen atom and n represents an integer from 1 to 5, inclusive.

Claim 4

A method for preparing a moisture curable organosiloxy-terminated isobutylene oligomer, said method comprising reacting an isobutylene oligomer exhibiting a number average molecular weight of from 1,000 to 100,000 and having a CH₂=CR˝- radical at each of the two terminal positions with at least a stoichiometric amount of an organosilicon compound of the formula in the absence of atmospheric moisture and the presence of a catalytically effective amount of a platinum-group metal or a compound of said metal as a hydrosilation catalyst, where the R substituents represent identical or different monovalent hydrocarbon radicals or halogenated monovalent hydrocarbon radicals, R′ represents an alkylene radical containing from 2 to 10 carbon atoms, R˝ represents a hydrogen atom or a methyl radical, X represents a hydrolyzable group that is bonded to silicon by means of a nitrogen atom or an oxygen atom, and n represents an integer from 1 to 5, inclusive.

Claim 5

A method for preparing a moisture curable organosiloxy-terminated isobutylene oligomer, said method comprising reacting an isobutylene oligomer exhibiting a number average molecular weight of from 1,000 to 100,000 and having a CH₂=CR˝- radical at each of the two terminal positions with at least a stoichiometric amount of an organosilicon compound of the formula in the absence of atmospheric moisture and the presence of a catalytically effective amount of a platinum-group metal or a compound of said metal as a hydrosilation catalyst, where the R substituents represent identical or different monovalent hydrocarbon radicals or halogenated monovalent hydrocarbon radicals, R′ represents an alkylene radical containing from 2 to 10 carbon atoms, R˝ represents a hydrogen atom or a methyl radical, X represents a hydrolyzable group that is bonded to silicon by means of a nitrogen atom or an oxygen atom, and n represents an integer from 1 to 5, inclusive.