Fast moisture curing and UV-moisture dual curing compositions
View Patent ↗The invention provides fast moisture and photo/moisture curing silicone compositions and methods for the preparation thereof. More particularly, the compositions provided are prepared from silanol and silane cappers; the cappers have an α-carbon bonded to the silicon atom allowing for a favorable hypervalent silicon transition state when reacting the silane and silanol. This favorable transition state enables both a fast endcapping reaction and contributes to the fast moisture curing properties of the inventive compositions.
1. A curable composition comprising:
a) a compound having the structural formula:
wherein R is a C 1-20 alkyl which is optionally substituted or an unsaturated free radical-curing group; R 1 is hydrogen or a C 1-6 hydrocarbon radical; R 2 is a hydrolyzable group; X is oxygen or
R 3 is H or C 1-12 hydrocarbyl group; and
b) a polymer having the structural formula:
wherein A is a backbone selected from the group consisting of organic and siloxane backbones, and R e is CH 3 or H, wherein formula I and formula II are present in amounts such that the resulting ratio of said hydrolyzable groups of formula I to said OH groups of formula II is 1.2.
2. The composition according to claim 1 , wherein said curable composition is a dual cure photo/moisture curable composition.
3. The method according to claim 2 , wherein R is alkenyl, which may be substituted or unsubstituted.
4. The composition according to claim 1 , wherein said curable composition is a moisture curable composition.
5. The method according to claim 4 , wherein R is a C 1-20 alkyl which is optionally substituted.
6. The method according to claim 4 , wherein R is a methyl group.
7. The composition according to claim 1 , wherein X is O.
8. The composition according to claim 1 , wherein R 2 is an alkoxy group having the formula R 4 O- wherein R 4 is a C 1-2 alkyl group.
9. The composition according to claim 1 wherein R is
and R 5 , R 6 and R 7 are independently selected from the group consisting of hydrogen, halogen and organo radicals.
10. The composition according to claim 1 wherein A is a polysiloxane.
11. A composition comprising
(a) a compound having the structural formula
wherein R is CH 3 , R 1 is hydrogen or a C 1-6 hydrocarbyl group, R 2 is OR 4 , R 4 is a C 1-2 alkyl group, and X is O, and
(b) a polymer having the structural formula
wherein A is a backbone selected from the group consisting of organic and siloxane backbones, and R e is CH 3 or H.
12. The curable composition of claim 11 or claim 1 wherein said reaction product has a skin over time when exposed to curingly effective conditions of 15 minutes or less.
13. The curable composition of claim 12 wherein said reaction product has a skin over time when exposed to curingly effective conditions of 5 minutes or less.