Room-temperature-curable silicone rubber composition
View Patent ↗A room-temperature-curable silicone rubber composition comprising (A) 100 parts by weight of a polydiorganosiloxan mixture comprising: (A-1) 20 to 95 wt. % of a polydiorganosiloxane having both molecular terminals capped with dialkoxysilyl groups or trialkoxysilyl groups, (A-2) 5 to 80 wt. % of a polydiorganosiloxane having a molecular terminal capped with dialkoxysilyl group or trialkoxysilyl group and the other molecular terminal capped with monoalkoxysilyl group, hydrosilyl group, trialkylsilyl group or trialkoxyalkylsilyl group, and (A-3) 0 to 30 wt. % of a polydiorganosiloxane having both molecular terminals capped with monoalkoxysilyl group, hydlosilyl group, trialkylsilyl group or trialkoxyalkylsilyl group, (B) one or more alkoxysilanes of the formula R5bSi(OR6)4-b or partial hydrolysis and condensation products thereof, and (C) an organotitanium compound. The composition is used as a sealant.
1. A room-temperature-curable silicone rubber composition comprising
(A) 100 parts by weight of a mixture comprising:
(A-1) 20 to 95 wt. % of a polydiorganosiloxane represented by the following general formula
(A-2) 5 to 80 wt. % of a polydiorganosiloxane represented by formula
and
(A-3) 0 to 30 wt. % of a polydiorganosiloxane represented by formula
where R 1 and R 2 are independently selected from the group consisting of alkyl groups and alkoxyalkyl groups, R 3 is selected from the group consisting of alkyl groups, cycloalkyl groups, aryl groups, aralkyl groups, halogenated hydrocarbon groups, and the cyanoalkyl group, R 4 is independently selected from the group consisting of —OSi R 2 3 , hydrogen and an alkoxy group, R 7 is R 2 or R 3 , each Y and Z is independently selected from the group consisting of oxygen and a divalent hydrocarbon group, α is 0 or 1, q is 0, 1 or 2, and n is a number that provides the respective polyorganosiloxanes with a viscosity within the range of 20 to 1,000,000 mPa·s at 25° C., said polyorganosiloxanes being selected from the group of compounds wherein:
when R 4 is —OSiR 2 3 , Y is independently selected from the group consisting of oxygen and a divalent hydrocarbon group, Z is a divalent hydrocarbon group, R 7 is R 2 and q is 0,1 or 2; and
when R 4 is independently selected from the group consisting of hydrogen and an alkoxy group, Y is independently selected from the group consisting of methylene or ethylene radicals, Z is independently selected from the group consisting of oxygen and a divalent hydrocarbon group, q is 2 and R 7 is R 3 ;
(B) 1 to 25 parts by weight of a material selected from the group consisting of (a) alkoxysilanes, (b) partial hydrolysis products of (a), and (c) condensation products of (b) thereof wherein (a) has the general formula
R 5 b Si(OR 6 ) 4-b ,
where R 5 is a monovalent hydrocarbon group, R 6 is independently selected from the group consisting of an alkyl group and an alkoxy alkyl group, and b is 0 or 1; and
(C) 0.5 to 10 parts by weight of an organotitanium compound.
2. The room-temperature-curable silicone rubber composition of claim 1 , where R 1 is independently selected from the group consisting of a methyl and ethyl radical.
3. The room-temperature-curable silicone rubber composition of claim 1 further comprising (D), 1 to 20 parts by weight of a fine silica powder.
4. The room-temperature-curable silicone rubber composition according to claim 1 further comprising (E), 0.1 to 5 parts by weight of an adhesion promoter.
5. The room-temperature-curable silicone rubber composition according to claim 1 further comprising (F), 0.1 to 5 parts by weight of a light stabilizer.
6. The room-temperature-curable silicone rubber composition of claim 1 wherein R 2 and R 3 are independently selected from the group consisting of methyl and ethyl radicals.
7. The room-temperature-curable silicone rubber composition of claim 1 wherein component (A-3) is present in an amount of from 0.5 to 15 wt %.
8. The room-temperature-curable silicone rubber composition of claim 1 comprising 2 to 10 parts by weight of component (B) for each 100 parts by weight of component (A).
9. The room-temperature-curable silicone rubber composition of claim 1 comprising 1 to 5 parts by weight of component (C) per each 100 parts by weight of component (A).
10. The room-temperature-curable silicone rubber composition of claim 1 wherein R 4 is independently selected from the group consisting of hydrogen and an alkoxy group, Y is independently selected from the group consisting of methylene or ethylene radicals, q is 2, R 7 is R 3 , and Z is oxygen.
11. The room-temperature-curable silicone rubber composition according to claim 10 wherein R 4 is hydrogen.
12. The room-temperature-curable silicone rubber composition according to claim 1 wherein R 4 is hydrogen.
13. A construction sealant prepared from the composition of claim 1 .
14. The room-temperature-curable silicone rubber composition according to claim 1 wherein R 4 is —OSi R 2 3 , R 7 is R 2 and q is 0, 1 or 2, and each Y and Z is independently selected from the group consisting of oxygen, a methylene radical, and ethylene radical.
15. A room-temperature-curable silicone rubber composition comprising
(A) 100 parts by weight of a mixture comprising:
(A-1) 20 to 95 wt. % of a polydiorganosiloxane represented by the following general formula
(A-2) 5 to 80 wt % of a polydiorganosiloxane represented by formula
and
(A-3) 0 to 30 wt.% of a polydiorganosiloxane represented by formula
where R 1 and R 2 are independently selected from the group consisting of alkyl groups and alkoxyalkyl groups, R 3 is selected from the group consisting of alkyl groups, cycloalkyl groups, aryl groups, aralkyl groups, halogenated hydrocarbon groups, and the cyanoalkyl group, R 4 is independently selected from the group consisting of —OSi R 2 3 , hydrogen and an alkoxy group, R 7 is R 2 or R 3 , each Y and Z is independently selected from the group consisting of oxygen and a divalent hydrocarbon group, α is 0 or 1, q is 0, 1 or 2, and n is a number that provides the respective polyorganosiloxanes with a viscosity within the range of 20 to 1,000,000 mPa·s at 25° C., said polyorganosiloxanes being selected from the group of compounds wherein:
when R 4 is —OSiR 2 3 , R 7 is R 2 and q is 0, 1 or 2; Y is independently selected from the group consisting of oxygen, a methylene radical, and ethylene radical; and Z is a divalent hydrocarbon group; and
when R 4 is independently selected from the group consisting of hydrogen and an alkoxy group, Y is independently selected from the group consisting of oxygen and a divalent hydrocarbon group, Z is independently selected from the group consisting of oxygen and a divalent hydrocarbon group, q is 2 and R 7 is R 3 ;
(B) 1 to 25 parts by weight of a material selected from the group consisting of (a) alkoxysilanes, (b) partial hydrolysis products of (a), and (c) condensation products of (b) thereof wherein (a) has the general formula
R 5 b Si(OR 6 ) 4-b ,
where R 5 is a monovalent hydrocarbon group, R 6 is independently selected from the group consisting of an alkyl group and an alkoxy alkyl group, and b is 0 or 1; and
(C) 0.5 to 10 parts by weight of an organotitanium compound.
16. The room-temperature-curable silicone rubber composition according to claim 15 wherein when R 4 is independently selected from the group consisting of hydrogen and an alkoxy group, Y is independently selected from the group consisting of methylene or ethylene radicals, Z is independently selected from the group consisting of oxygen and a divalent hydrocarbon group, q is 2 and R 7 is R 3 .