GB824436A - Organosiloxane water-repellent compositions - Google Patents

Abstract

A siloxane composition comprises a mixture of (a) an organopolysiloxane mixture soluble in organic solvents and comprising (1) 15 to 80% by weight of (a)+(b) of a siloxane of the average general formula R1nSiO 4-n,/2 where each R1 is an alkyl or alkenyl radical of less than 4 C atoms or a monocyclic aryl radical and n has an average value of 2.0 to 2.9; (2) 5 to 70% by weight of (a)+(b) of a copolymer composed of (CH3)2SiO0.5 units and SiO2 units in such proportion that the ratio of CH3/Si is in the range 1.0 : 1 to 2.4 : 1 ; (b) 15 to 50% by weight of (a)+(b) of Ti(OR)4 or an aliphatic hydrocarbon-soluble partial hydrolysate thereof, wherein each R is an aliphatic hydrocarbon radical having less than 13 C atoms or a hydroxylated aliphatic hydrocarbon radical having less than 13 C atoms and less than 4 OH groups; (c) a nitroaliphatic compound or nitrobenzene; and (d) an organic solvent other than (c). Titanium esters specified are esters of methyl, ethyl, allyl, isopropyl, cyclohexyl and octyl alcohols; ethylene, propylene, octylene, diethylene, tripropylene and tetraethylene glycols; and glycerine. Solvents specified are Stoddard solvent, naphtha mineral spirits, perchloroethylene, benzene, toluene and xylene. Additives specified are nitro-methane, -ethane, -propane and -benzene, and are used in amount e.g. from 0.0002 to 0.1 mol. per ounce of the siloxane-solvent solution. The novel compositions resist the tendency to turn blue when exposed to sunlight. In examples, (1, 2), the compositions consist of naphtha mineral spirit solutions of a liquid dimethylsiloxane, tetraoctyl titanate, a (CH3)3SiO0.5-SiO2 copolymer and different nitro compounds; (3) the compositions are similar except that different Ti esters are used. Uses.-For imparting water-repellency to porous materials, e.g. textiles, masonry, leather and wood. Specifications 736,378 and 750,947 are referred to.