| 摘要 |
<p>PREPARATION OF MULTI-BRANCHED SILICON-FUNCTIONAL POLYORGANOSILOXANES In the preparation of multi-branched equilibrated mixed acyloxycontaining and chlorine-containing organo polysiloxanes by reacting a chlorosilane of the formula RaSiCl4-a wherein a = 0 or 1, with at least one organosiloxane containing units of the formula R2R'SiO1/2, RR'SiO, R'SiO3/2 and/or SiO2 wherein R is hydrogen or an aliphatic, aromatic, saturated or unsaturated, optionally halogen-substituted or cyano-substituted monovalent hydrocarbon radical with up to 8 C atoms and R' is chlorine, hydroxyl, hydrogen or an aliphatic, aromatic, saturated or unsaturated, optionally halogen-substituted or cyano-substituted monovalent hydrocarbon radical with up to 8 C atoms, in proportions such that the number of all the SiCl groups is always at least 1.5 times greater than the number of SiOH groups, in the presence of (a) fluoro-alkanesulphonic acid or salt thereof and (b) relative to the chlorine atoms bonded to silicon, at least 1.1 times the molar amount of a concentrated monobasic carboxylic acid, the improvement which comprises adding a portion of the carboxylic acid in a first stage, and in a second stage adding the balance of the carboxylic acid along with water in the amount required to achieve the desired degree of branching. Advantageously the fluoroalkanesulphonic acid is a perfluoroalkanesulphonic acid containing up to 8 carbon atoms, and it or its salt is employed in about 0.05 to 1.5% by weight of chlorosilane plus organosiloxane, the carboxylic acid is acetic acid, the reaction is carried out at a temperature up to about 135.degree.C, the organosiloxane comprises a cyclosiloxane of the formula (RR'=SiO)3-5' and about half the acetic acid is added in each stage.</p> |
