POLYMER, COMPOSITIONS AND PROCESS FOR PREPARING THEM

摘要

There is described a process for preparing an silane-functional oligomer (such as an alkoxysilane polyurethane) suitable for use as a crosslinkable coating component, the process comprising the steps of: 1) reacting an aminoalkyl silane with a cyclic carbonate, lactone or lactam to form a hydroxyl (OH) or imino (NH) functional silane intermediate, 2) reacting the silane intermediate from step 1) (optionally immediately without isolation) with a diisocyanate (diNCO) to form a silane functional polyurethane; where in step 2) the molar ratio of the total amount OH or NH groups on the silane intermediate of step 1) to the diisocyanate is from 1.8 to 2.2 (preferably about 2.0) and the resultant silane polymer is substantially-free of isocyanate groups thereon.