Patent ID: 7427648

Claim:
A hydrophilic siloxane copolymer prepared by the process of (a) reacting in a first step: organopolysiloxane(s) (1) which have at least one Si-bonded hydrogen atom, with substantially linear oligomeric or polymeric compounds (2) of the formula R 1 -(A-C n H 2n ) m -A 1 -H (I) where R 1 is a monovalent optionally substituted hydrocarbyl radical capable of adding Si—H groups in a hydrosilylation reaction, A is a bivalent polar organic radical individually selected from the group consisting of —O—, —C(O)—O—, —O—C(O)—, —O—C(O)—O—, —C(O)—NH—, —NH—C(O)—, urethane radicals and urea radicals, A 1 is a bivalent polar organic radical individually selected from the group consisting of —O—, —NH— and —NR′—, where R′ is a monovalent hydrocarbyl radical of 1 to 18 carbon atoms, n is an integer from 1 to 20, and m is zero or a positive integer, to form an -(A-C n H 2n ) m -A 1 H group-containing intermediate (4); (b) reacting in a second step: the resulting -(A-C n H 2n ) m -A 1 H group-containing intermediate (4) with at least one organic compound (5) which has two or more isocyanate groups per molecule, the reaction taking place in the presence of at least one further organic compound (6) which is reactive toward isocyanate groups and contains at least one tertiary amine group, to form an amino-group-containing intermediate (7); and (c) a third step, quaternizing: the amino-group-containing intermediate (7) from step (b), partially or completely, with at least one alkylating agent (8), with the proviso that the water content of the compounds (1) and (2), is lower than 2000 weight ppm, in each case based on the total weight of compounds (1) and (2).