GB850419A - Organosilicon coating or bonding composition and process of forming and using same - Google Patents

Abstract

A composition, for coating or bonding silicone rubber to substrates, comprises a mixture of silanes (A) R 1Si(OR)3 and (B) R2.Si(R3)3-n (OR)n, wherein each R is an alkyl radical of 1 to 10 C atoms. or an aryl radical, R1 is an unsaturated aliphatic radical, R2 is an aminoalkyl radical of 2 to 10 C atoms, R3 is an alkyl radical of 1 to 4 C atoms and n is 2 or 3, preferably in the form of an organic solvent solution thereof and having a substantially neutral pH value. The unsaturated radicals of silane (A) may be vinyl, chlorovinyl, cyclohexenyl, bicycloheptenyl, butenyl, chlorobutenyl, cyclopentadienyl, chlorocyclohexenyl, dichlorocyclohexenyl, dichlorobutenyl, allyl, chloroallyl, decenyl and the radical produced by reacting dicyclopentadiene with vinyltrialkoxysilanes. The weight ratio of aminoalkyl to unsaturated silane preferably varies between 1:9 and 9:1 depending upon the intended use of the compound. The preferred solvents are those miscible with water, e.g. alcohols, glycols, ketones and glycol ethers, certain silanes, e.g. a chlorovinyltriethoxy silane, are sufficiently acid to provide the desired pH, otherwise acids or acidic materials, e.g. HCl, HNO3, b -carbethoxyethylytri-and b -carbethoxypropylmethyldiethoxy silanes, are used to adjust the pH of the compositions. The compositions are applied to the substrate and allowed to dry, e.g. for 20 hours at room temperature or for 10 minutes at 220 DEG F; and in bonding silicone rubber to the coated substrate, the assembly is heated e.g. at 230 DEG to 350 DEG F. for 10 to 40 minutes under pressure. Examples are given.ALSO:A composition comprising a mixture of an aminoalkyltrialkoxy silane and an unsaturated aliphatic alkoxysilane, preferably in solution in a water-miscible solvent, e.g. an alcohol, glycol, ketone or glycol ether, and having a substantially neutral pH value (see Group IV(a)), is used for coating metal surfaces or for bonding silicone rubber to a substrate. In coating metal surfaces, e.g. steel, stainless steel, brass, Cu, Al, Mg, or any alloy thereof, the composition is simply applied, as by dipping, spraying, brushing or wiping, and allowed to dry, e.g. for 20 hours at room temperature or for 10 minutes at 220 DEG F. In bonding silicone rubber to a substrate, e.g. of any of the above metals or alloys, ceramic, glass, glass fabric, wood, resins, resin-bonded bodies, rubber, hydraulic cement or textiles made e.g. of nylon or ethylene glycol-dimethylterephthalate fibres, the composition is interposed between the two, as by applying the composition to the substrate surface or to the silicone rubber surface and allowing the composition to dry, and the resulting assembly is heated under pressure, e.g. at 230 DEG to 350 DEG F. for 10 to 40 minutes, with subsequent heat-ageing at 300 DEG to 500 DEG F. Uncured silicone rubber, i.e. the convertible siloxane, filler and organic peroxide, may be used and the rubber formed in situ during the bonding step. The metal surface to be coated or bonded is cleaned, e.g. by degreasing followed by blasting with steel shot, grit or sand, or by chemical means. In examples, a silicone rubber stock is bonded to (1-14) Al, Cu and steel; (15) a glass panel; (16) an ethylene glycol-dimethylterephthalate fabric; (19) A1 and Cu, after each surface has been coated with the above silane composition. In Examples 17, 18, various metals are coated with the silane composition.