摘要 |
Organopolysiloxanes containing units of the formulae O3-a/2RaSi—Y—(SiRaO3-a/2)b and R1cSiO4-c are prepared by catalyzed reaction, in a first step, of a mixture of X3-aRaSi—Y—(SiRaX3-a)b and R1cSiX4-c and siloxanes which have structural units of the formulae O3-a/2RaSi—Y—(SiRaO3-a/2)b and R1cSiO4-c and having weight average molar mass of 100 to 950 g/mol and reacting the mixture obtained therefrom with water or aqueous acid, producing organopolysiloxanes having a weight average molar mass of 1,000 to 100,000 g/mol, wherein R and R1 each are monovalent C1-30 SiC-bonded organic groups optionally containing one or more N and/or O atoms, Y is a 2-12 valent C1-30 organic group optionally containing one or more O atoms, X is a hydrolyzable group, a is 0 or 1, b is 1 to 11, and c is 0, 1, 2, or 3. |