GB1192506A - Improvements in "Silanol-Containing Organopolysiloxane Resins and a Method for Making Them" - Google Patents

Abstract

1,192,506. Organopolysiloxanes. GENERAL ELECTRIC CO. 27 Sept., 1968 [29 Sept., 1967], No. 46061/68. Heading C3T. An organopolysiloxane containing silanol groups (I) is prepared by agitating a mixture of: (A) 1 part by weight of an organohalosilane; (B) 1À7 to 10 parts by weight of water; (C) 0À2 to 5 parts by weight of acetone; (D) 0À3 to 5 parts by weight of a water immiscible solvent; and (E) 0 to 1 mole per mole of halogen attached to (A) of a C 1-8 aliphatic monohydric alcohol. An organic solvent solution of I is separated from the reaction mixture. (A) is selected from: an organotrihalosilane (II), a mixture of an organotrihalosilane and a diorganodihalosilane (III), the reaction product of (E) with II or a mixture of II and III which has an average of up to 1 alkoxy radical per halogen radical or a mixture of such a reaction product with II or II and III. The organic radicals of (A) and I are selected from (halogenated) monovalent hydrocarbon radicals and cyanoalkyl radicals. The organopolysiloxanes prepared may have 1 to 1À2, 1À2 to 1À4 or 1À4 to 1À8 organic radicals per Si atom. A preferred procedure comprises: (1) agitating at 0-80‹ C. a mixture of (A) 1 part of an organochlorosilane, (B) 2 to 6 parts of water, (C) 0À3 to 2 parts of acetone, (D) 0À6 to 2 parts of toluene and from 0 to 1 mole of isopropanol per mole of chlorine in (A); (2) separating the toluene layer from the hydrolysis mixture of (1) containing a silanol containing organopolysiloxane having an average of 1 to 1À8 organic radicals per Si atom selected from methyl, phenyl or mixtures thereof; and (3) stripping the toluene layer of (2) to a solids concentration of about 95% by weight. Examples relate to the preparation of silanol containing phenylpolysiloxanes, methylpolysiloxanes, methylphenylpolysiloxanes and hexylphenylpolysiloxanes.