End production manner null of the polydyorganosiloxane block in the alkoxy sill ethylene basis

摘要

PURPOSE: To obtain a polyorganosiloxane generating no by-product by a method wherein after a polyorganosiloxane, whose terminal ends are blocked with hydroxyl groups, is reacted with an SiH-contg. compd., and the product is reacted with a vinyltrialkoxysilane. ;CONSTITUTION: At first, a polyorganosiloxane, whose terminal ends are blocked with hydroxyl groups of formula I (wherein R is a 1-18C monovalent hydrocarbon, a monovalent cyanoalkyl, etc.; X has a value which provides a viscosity of 0.5-3,000 pa.S at 25°C to the polymer) is mixed with excess amt. of SiH-contg. compd. with 2-4 SiH atomic groups (e.g. a compd. of formula II) and a platinum catalyst and after the mixture is reacted at a temp. of 25-150°C. it is heated to 25-150°C under a pressure of 25 mmHg to remove excess SiH-contg. compd. from the reaction mixture. Then, after the product is reacted with a vinyltrialokoxysilane of formula III (wherein R" is methyl, propyl, etc.), the reaction mixture is heated at a temp. of 25-150°C under a pressure of 25 mmHg to remove excess vinyltrialkoxysilane.;COPYRIGHT: (C)1992,JPO