GB778348A - Bonding silicone rubber to solid materials - Google Patents

Abstract

Silicone rubber is bonded to a solid surface by coating the surface with certain titanic acid esters which may be partly hydrolysed or may be mixed with a partly hydrolysed alkyl polysilicate, and applying to the coated surface a silicone rubber composition containing 1-10 per cent of a partly hydrolysed alkyl polysilicate. The titanic acid esters are compounds of the general formular Ti(OR)4 or hydrocarbon soluble partial hydrolysates thereof, where R is an aliphatic hydrocarbon radical, or a hydroxylated aliphatic hydrocarbon radical with less than 4 hydroxyl groups per radical, of less than 13 carbon atoms. The silicone rubber is a toluene-soluble organo-polysiloxane of general formula <FORM:0778348/III/1> where R1 is a monovalent hydrocarbon radical and n has an average value of 1.99-2. The silicone rubber layer is vulcanized by heating. The backing material may be of metal (including car bodies), ceramic, glass, one of a number of cellulose esters or ethers or vinyl resins, polystyrene, polyamides, polyesters, polyethylene, fluorocarbon polymers, organic elastomers, siloxane and sulphur containing elastomers, acrylic polymers and copolymers, natural and synthetic organic fabrics, or wood or may be an oriented film of polyethylene glycol terephthalate. The R group may be methyl, ethyl, decyl, octylene glycol, 2-ethyl hexyl, dodecyl, isopropyl or any mixture thereof. The R1 group may be alkyl, aryl, alkaryl, aralkyl, cycloaliphatic or alkenyl. The preferred alkyl polysilicates are methyl, ethyl or butyl polysilicates or mixtures thereof. Various fillers and vulcanizing agents such as one of a number of specified organic peroxides or those given in Specifications 764,246 and 743,950 [both in Group IV(a)] may be added to the siloxane mixture which may be applied, in solution in benzene or toluene or without dilution, by spraying, dipping or doctoring. A further layer of a silicone adhesive, e.g. of the kind described in Specification 767,797 [Group IV(a)] may be applied to the first silicone layer.