Use of organopolysiloxane compositions which cure at ambient temperature in coating electrical and electronic devices

Claim 1

A process for coating an electric or electronic device which comprises applying to the device an organopolysiloxane composition which consists essentially of a mixture of the following ingredients, by weight: i. 100 parts of a α,ω-dihydroxydiorganopolysiloxane polymer, of viscosity at least about 600 19 cPo at 25°C, consisting essentially of diorganosiloxy units, the organic radicals bonded to the silicon atoms being selected from alkyl radicals with 1 to 3 carbon atoms, halogenoalkyl radicals with 3 or 4 carbon atoms, the vinyl radical, aryl or halogenoaryl radicals with 6 to 8 carbon atoms or cyanoalkyl radicals with 3 or 4 carbon atoms, with the proviso that at least 50 % of these organic radicals are methyl radicals; ii. 1 to 15 parts of an organosilicon compound which is either: a. a monomer of the formula (A): R x Si[(OCH 2 CH 2 ) a OR'] 4-x , in which R represents a hydrocarbon radical with 1 to 8 carbon atoms, R' represents an alkyl radical with 1 to 4 carbon atoms, and x and a independently represent zero or 1, or b. a polymer resulting from the partial hydrolysis of at least one monomer of formula Si(OR') 4 , in which R' is as defined above; iii. 0.2 to 6 parts of an organic derivative of titanium, which is either: a. a monomer of the formula (B): Ti[(OCH 2 CH 2 ) b OR"] 4 , in which R" represents an alkyl radical with 1 to 10 carbon atoms and b represents zero, 1 or 2 ; such that when b is zero, the alkyl radical has 3 to 10 carbon atoms and when b is 1 or 2 , the alkyl radical has 1 to 4 carbon atoms, b. a polymer resulting from the partial hydrolysis of at least one monomer of the formula Ti (OR").sub. 4, in which R" represents an alkyl radical with 3 to 10 carbon atoms, c. a titanium chelate of the formula (C): ##EQU13## in which Q represents an alkyl radical with 1 to 4 carbon atoms, a phenyl radical or an alkoxy radical with 1 to 3 carbon atoms; R" represents an alkyl radical of 3 to 10 carbon atoms; y represents 2 or 3 : R 3 represents a hydrogen atom, a methyl radical or a chloromethyl radical; Q' represents an alkyl radical with 1 to 5 carbon atoms or a chloromethyl radical; or R 3 and Q', together with the two carbon atoms to which they are attached, together form a phenyl nucleus, in which case Q represents an alkoxy radical or a hydrogen atom, or d. a titanium chelate of the formula (D): ##EQU14## in which R 4 and R 5 , which may be indentical or different, represent hydrogen atoms or methyl radicals; Q, Q' and R 3 are as defined above and n represents zero or 1; iv. 0 to 100 parts of an optionally organosilicon-treated inorganic filler; v. 0 to 100 parts of plasticiser and/or organosilicon stabiliser and; vi. 0.5 to 8 parts of an organosilicon resin consisting of units of the formulae R" ' (CH 3 ) 2 SiO 0 .5 and SiO 2 , in which R" ' represents an alkyl radical with 1 to 3 carbon atoms or the vinyl radical and the ratio of the number of R" ' (CH 3 ) 2 SiO 0 .5 units to the number of SiO 2 units is from about 0.411 to about 1.2/1, and curing the composition on the device.