Method of coating a substrate with curable organopolysiloxane compositions

Claim 1

A method of forming a coating on a substrate which comprises coating a substrate with an organopolysiloxane composition vulcanisable at ambient temperature and above, comprising in parts by weight: A. 100 parts of an α,ω-dihydroxydiorganopolysiloxane polymer, of viscosity 500 cPo at 25° C to 1 million cPo at 25° C, in which each organic radical bonded to each silicon atom, independently is an alkyl radical with 1 to 3 carbon atoms, a halogenoalkyl radical with 3 or 4 carbon atoms, a vinyl radical, an aryl radical with 6 to 8 carbon atoms, a halogenoaryl radical with 6 or 7 carbon atoms or a cyanoalkyl radical with 3 or 4 carbon atoms; at least 60% of these organic radicals being methyl radicals; B. 10 to 50 parts of a methylpolysiloxane resin consisting of units of the formula R(CH 3 ) 2 SiO 0 .5 and units of formula SiO 2 , wherein R represents an alkyl radical with 1 to 3 carbon atoms or a vinyl radical, and the value of the ratio of the number of R(CH 3 ) 2 SiO 0 .5 units to the number of SiO 2 units is 0.4:1 to 1.2:1, these polymers containing at least 0.5% but not more than 3.5% by weight of hydroxyl groups bonded to the silicon atoms; C. 10 to 70 parts of a filler; D. 0.5 to 15 parts of an aminoorganosilicon compound which is an aminoorganosilane of the general formula (i) (R"O).sub.3.sub.-p R'.sub.p Si[(CH.sub.2).sub.n O].sub.m (CH.sub.2).sub.t NHQ in which R' represents an alkyl group with 1 to 4 carbon atoms, a vinyl group or a phenyl group, R" represents a methyl, ethyl or methoxyethyl radical, Q represents a hydrogen atom or the radical --(CH 2 ) 2 NH 2 , p and m represent 0 or 1, n represents 1, 2, 3 or 4, and t represents 2 or 3; or an aminoorganopolysiloxane produced by reacting the aminoorganosilane (i) above, in which p is 0, with a hydroxylic methylpolysiloxane polymer (ii) containing at least 2% by weight of hydroxyl groups bonded to the silicon atoms, of viscosity 1 cPo at 25° C to 1,000 cPo at 25° C, of the average general formula (CH 3 ) a (HO) b --SiO.sub.(4 -a -b/2 ) in which a represents any number from 1.6 to 2.3 and b represents any number ranging from 0.1 to 1; the amounts of aminoorganosilane (i) and hydroxylic methylpolysiloxane polymer (ii) being such that there are 0.4 to 1.2 mols of (i) per gram(hydroxyl group) of (ii); and E. 0 to 10 parts of at least one compound selected from the group consisting of alkyl silicates and alkyl polysilicates in which the alkyl radical has 1-3 carbon atoms; and then curing the coating of the composition on the substrate at ambient temperature or above.

Claim 2

A method of forming a coating on a substrate which comprises coating a substrate with an organopolysiloxane composition vulcanisable at ambient temperature and above, comprising in parts by weight: A. 100 parts of an α,ω-dihydroxydiorganopolysiloxane polymer, of viscosity 500 cPo at 25° C to 1 million cPo at 25° C, in which each organic radical bonded to each silicon atom, independently is an alkyl radical with 1 to 3 carbon atoms, a halogenoalkyl radical with 3 or 4 carbon atoms, a vinyl radical, an aryl radical with 6 to 8 carbon atoms, a halogenoaryl radical with 6 or 7 carbon atoms or a cyanoalkyl radical with 3 or 4 carbon atoms; at least 60% of these organic radicals being methyl radicals; B. 10 to 50 parts of a methylpolysiloxane resin consisting of units of the formula R(CH 3 ) 2 SiO 0 .5 and units of formula SiO 2 , wherein R represents an alkyl radical with 1 to 3 carbon atoms or a vinyl radical, and the value of the ratio of the number of R(CH 3 ) 2 SiO 0 .5 units to the number of SiO 2 units is 0.4:1 to 1.2:1, these polymers containing at least 0.5% but not more than 3.5% by weight of hydroxyl groups bonded to the silicon atoms; C. 10 to 70 parts of a filler; D. 0.5 to 15 parts of an aminoorganosilicon compound which is an aminoorganosilane of the general formula (i) (R"O).sub.3.sub.-p R'.sub.p Si[(CH.sub.2).sub.n O].sub.m (CH.sub.2).sub.t NHQ in which R' represents an alkyl group with 1 to 4 carbon atoms, a vinyl group or a phenyl group, R" represents a methyl, ethyl or methoxyethyl radical, Q represents a hydrogen atom or the radical --(CH 2 ) 2 NH 2 , p and m represent 0 or 1, n represents 1, 2, 3 or 4, and t represents 2 or 3; or an aminoorganopolysiloxane produced by reacting the aminoorganosilane (i) above, in which p is 0, with a hydroxylic methylpolysiloxane polymer (ii) containing at least 2% by weight of hydroxyl groups bonded to the silicon atoms, of viscosity 1 cPo at 25° C to 1,000 cPo at 25° C, of the average general formula (CH 3 ) a (HO) b --SiO.sub.(4 -a -b/2 ) in which a represents any number from 1.6 to 2.3 and b represents any number ranging from 0.1 to 1; the amounts of aminoorganosilane (i) and hydroxylic methylpolysiloxane polymer (ii) being such that there are 0.4 to 1.2 mols of (i) per gram(hydroxyl group) of (ii); and E. 0 to 10 parts of at least one compound selected from the group consisting of alkyl silicates and alkyl polysilicates in which the alkyl radical has 1-3 carbon atoms; and then curing the coating of the composition on the substrate at ambient temperature or above.