GB759013A - Process for accelerating the condensation of organopolysiloxanes - Google Patents

Abstract

The further condensation of an organo-polysiloxane containing silicon-bonded hydrocarbon radicals and Si-H groups is effected in the presence of a complex compound of aluminium with acetyl acetone, acetoacetic acid ethyl ester or a malonic acid alkyl ester as accelerator, at a temperature not substantially exceeding 100 DEG C. The accelerator is preferably used in amount of 0.01 to 1 per cent by weight of the siloxane and may be added to the siloxanes per se or to solutions or emulsions thereof. The siloxanes specified may be oils or resins, and contain, in addition to Si-H groups, alkyl radicals, e.g. methyl to octadecyl, and/or aryl radicals, e.g. phenyl, and may contain alkoxy radicals. Other resins, pigments or fillers may be added. In examples, textile fabric or paper is waterproofed by impregnating with (1) a toluene solution, or (2) an aqueous emulsion of the hydrolysate of (CH3)2SiCl2 and CH3.SiHCl2 and aluminium acetylacetonate and heating at 80 DEG to 100 DEG C. for 5 minutes; (3) cotton pieces are waterproofed by impregnating with a methylene chloride solution of the hydrolysate of (CH3)2SiCl2 and C2H5SiHCl2 and the Al compound of ethyl-acetoacetate and heating at 100 DEG C. for 10 minutes; (4) cotton fabric is waterproofed by impregnating with a toluene solution of the hydrolysate of CH3.SiHCl2, CH3.C6H5.SiCl2 and CH3.SiCl3 and the aluminium compound of ethyl malonate, and heating at 90 DEG C. for 7 minutes. Specifications 630,319 and 635,445 are referred to.