Adhesion promoting compositions and curable organosiloxane compositions containing same
AssigneeDow Corning Corporation
InventorsTheresa E. Gentle, Michael A. Lutz
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Abstract
Adhesion-promoting additives for use in curable organosiloxane compositions comprise 1) at least one organosiloxane comprising a) silicon bonded hydrogen atoms and/or ethylenically unsaturated substituents bonded to silicon through carbon and b) at least one silicon atom containing three hydrolyzable groups, and 2) at least one silane containing four alkoxy or enoloxy groups or three of these groups and a hydrocarbon radical containing an epoxy or ethylenically unsaturated group as a substituent.
Claims8
An adhesion promoting additive for curable organosiloxane compositions, said additive comprising
- (I) an organosiloxane comprising at least one unit of the general formula R.sup.1 R.sup.2.sub.a SiO.sub.(3-a)/2 and at least one unit containing three silicon-bonded hydrolyzable groups selected from the group consisting of alkoxy and enoloxy;
- and
- (II) a silane of the formula R.sup.3.sub.b Si(OR.sup.4).sub.4-b or bis-silylalkane of the formula [(R.sup.4 O).sub.3 Si].sub.2 R.sup.5
- wherein R.sup.1 is selected from the group consisting of hydrogen, alkenyl radicals, and CH.sub.2 .dbd.CR.sup.6 C(O)OR.sup.7 --, R.sup.2 represents an unsubstituted or substituted monovalent hydrocarbyl radical, R.sup.3 is selected from the group consisting of monovalent ethylenically unsaturated groups bonded to silicon through carbon and epoxide-substituted hydrocarbon radicals, OR.sup.4 is selected from the group consisting of alkoxy groups containing from 1 to 4 carbon atoms and enoloxy groups containing from 3 to 6 carbon atoms, R.sup.5 is an alkylene radical, R.sup.6 is hydrogen or methyl, R.sup.7 is an alkylene radical, a is 0, 1 or 2, and b is 0 or 1.
In an improved curable organosiloxane composition comprising
- A. a polyorganosiloxane containing at least two groups per molecule that react to achieve curing of said composition;
- B. a curing agent in an amount sufficient to cure said composition;
- and
- C. an amount of a curing catalyst sufficient to promote curing of said composition;
- wherein curing of said composition is achieved by the reaction of silicon-bonded hydrogen atoms on said curing agent with alkenyl radicals or silanol groups present on said polyorganosiloxane or by the photoinduced generation of free radicals,
- the improvement comprising the presence in said composition of an adhesion promoting additive comprising
- (I) an organosiloxane comprising at least one unit of the general formula R.sup.1 R.sup.2.sub.a SiO(.sub.3-a)/2 and at least one unit containing three silicon-bonded hydrolyzable groups selected from the group consisting of alkoxy and enoloxy;
- and
- (II) an organosilicon compound selected from the group consisting of silanes of the formula R.sup.3.sub.b Si(OR.sup.4).sub.4-b and bis-silylalkanes of the formula [(R.sup.4 O ).sub.3 Si].sub.2 R.sup.5 wherein R.sup.1 is selected from the group consisting of hydrogen, alkenyl radicals, and CH.sub.2 .dbd.CR.sup.6 C(O)OR.sup.7 --, R.sup.2 represents an unsubstituted or substituted monovalent hydrocarbyl radical, R.sup.3 represents a monovalent ethylenically unsaturated group bonded to silicon through carbon or an epoxide-substituted hydrocarbon radical, OR.sup.4 represents an alkoxy group containing from 1 to 4 carbon atoms or an enoloxy group containing from 3 to 6 carbon atoms, R.sup.5 is an alkylene radical, R.sup.6 is hydrogen or methyl, R.sup.7 is an alkylene radical, a is 0, 1 or 2, and b is 0 or 1.
Dependencies are inferred from the claim text.