Patent ID: 8304569

Claim:
A process for preparing isocyanate-terminated siloxanes comprising reacting at least one Si-OH-terminated, branched or unbranched siloxane (A) comprising units of the formula (I): R a R 1 b (R 2 O) c SiO 4-a-b-c/2 (I), where R is a monovalent, SiC-bonded, substituted or unsubstituted hydrocarbon radical optionally interrupted by oxygen atoms, R 1 is an Si-bonded hydroxyl group, R 2 are identical or different and are each a monovalent, substituted or unsubstituted hydrocarbon radical optionally interrupted by heteroatoms, a is 0, 1, 2 or 3, b is 1, 2 or 3 and c is 0, 1, 2 or 3, with the proviso that the sum a+b+c≦3 and at least one unit having b different from 0 is present, with at least one optionally protected isocyanate-functional α-silane of the formula: (R 2 O) n R m Si—CH 2 —NR 3 (II), where R 3 is CO or H—CO—Z, where Z is a monovalent, substituted or unsubstituted hydrocarbon radical optionally interrupted by heteroatoms, n is 1, 2 or 3 and m is 0, 1 or 2, with the proviso that the sum m+n=3.