Patent ID: 8907039

Claim:
A method for preparing (hydroxymethyl)polysiloxanes having lateral hydroxymethyl groups of the formula Ib HO{(SiR 11 2 O) α [SiR 12 —CH 2 —OH]} β (SiR 11 2 O) α H (Ib) comprising reacting silanol-containing organosiloxanes of the formula IIa, HO(SiR 11 2 O) α H (IIa) with compounds of the formula IIIa X—[SiR 12 (OR 13 )—CH 2 —O] n —Y (IIIa) where n is greater than zero, α is an integer from 2 to 20,000, β is an integer from 1 to 10,000, R 11 is methyl, ethyl, vinyl, allyl or phenyl, R 12 is methyl, ethyl, vinyl, allyl, phenyl, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy or tert-butoxy, R 13 is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl or tert-butyl, X is a group R 2 or Q 1 or a hydroxyl, alkoxy, or acyloxy hydrolysable group or is a bond together with Y, with the proviso that X, if n=1, is a hydrolyzable group or a siloxane residue which comprises at least one hydrolyzable group or is a bond together with Y, Y is hydrogen, an acyl group, a silyl group, a siloxanyl group, or is a bond together with X, R 2 is hydroxyl, or a cyclic or acyclic, linear or branched, aromatic or aliphatic or olefinic, saturated or unsaturated C 1 -C 20 hydrocarbon residue, a C 1 -C 20 hydrocarbonoxy residue, a C 4 -C 40 polyether residue, or a Si i —Si 20 siloxanoxy residue, each optionally substituted with Q 1 , optionally interrupted by one or more groups Q 2 or comprising one or more groups Q 2 , Q 1 is a heteroatom-containing monovalent residue, Q 2 is a heteroatom-containing divalent residue or a heteroatom-containing trivalent residue, wherein the quantitative ratio of compounds of the formula IIa to compounds of the formula IIIa is selected such that the quantitative ratio of silanol groups in formula IIa less the two residual terminal silanol groups in the compounds of the formula Ib, to the quantitative ratio of the [SiR 12 (OR 13 )—CH 2 —O] units in formula IIIa, based on the number n of occurrences thereof in formula IIIa, is 1.6 to 2.4.