Room-temperature, moisture-curable, primerless, poluyrethane-based adhesive composition and method

Claim 1

A one-component, primerless, moisture-curable sealant composition for bonding glass directly to electrocoated metal substrates 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 divalent hydrocarbon radicals, divalent hydrocarbon ether radicals, and divalent hydrocarbon amino radicals; A is selected from -S- and -NR²- where R² is hydrogen or alkyl of from one to six carbon atoms; and (b) an electrocoat adhesion promoter having the structure, including hydrohalide salts thereof, where x is an integer of from one to three; R³, R⁴ may and R⁵ may be the same or different and are selected from alkyl and alkoxyl of from one to four carbon atoms; B is or R⁶ where the group R⁶ is hydrogen, or -(CH₂) y NHR⁸ where R⁷ is alkyl of from one to four carbon atoms or alkylene of one to four carbon atoms, and R⁸ is hydrogen or -(CH₂) z NH₂ wherein y and z may be the same or different and are integers of from one to three.

Claim 9

A method of bonding fixed-window glass panels to a motor vehicle body characterized by a) applying a conventional electrocoat paint coating to the metal body of the motor vehicle; b) applying masking means to those portions of the electrocoat painted motor vehicle body set aside to receive a bead of fixed-glass panel sealant; c) applying one or more decorative and protective paint coatings to the masked motor vehicle body; d) removing the masking means; e) applying directly to the previously masked electrocoat painted portions of the motor vehicle body a bead of the polyurethane-based sealant composition according to any one of claims 1 to 8; and f) affixing a glass window panel to the sealant bead.