Curable organopolysiloxane composition and cured product thereof
A curable organopolysiloxane composition is provided. The curable organopolysiloxane composition comprises: (A) a diorganopolysiloxane having at least two silicon-bonded alkenyl groups per molecule; (B) an organopolysiloxane resin; (C) a mixture of (C 1 ) a diorganopolysiloxane endblocked with silicon-atom bonded hydrogen atoms at both molecular terminals and (C 2 ) an organohydrogenpolysiloxane having at least three silicon-bonded hydrogen atoms per molecule; (D) a polyether having at least one aliphatic unsaturated group per molecule; and (E) a hydrosilylation catalyst.
1. A curable organopolysiloxane composition comprising:
(A) 100 parts by mass of a diorganopolysiloxane having at least two silicon-bonded alkenyl groups per molecule, wherein at least 90 mol % of silicon-bonded groups in component (A) other than alkenyl groups in component (A) are methyl groups;
(B) 30 to 100 parts by mass of an organopolysiloxane resin consisting essentially of R 1 3 SiO 1/2 units and SiO 4/2 units, wherein each R 1 is independently a monovalent hydrocarbon group, however, at least one R 1 per molecule is an alkenyl group, and a mole ratio of R 1 3 SiO 1/2 units to SiO 4/2 units is from 0.6 to 1.7;
(C) a mixture of
(C 1 ) a diorganopolysiloxane endblocked with silicon-atom bonded hydrogen atoms at both molecular terminals and
(C 2 ) an organohydrogenpolysiloxane having at least three silicon-bonded hydrogen atoms per molecule,
in an amount sufficient to provide from 0.1 to 5 silicon-bonded hydrogen atoms per alkenyl group in components (A) and (B);
(D) a polyether having at least one aliphatic unsaturated group per molecule, in an amount of 0.20 to 0.40 mass % of the composition; and
(E) a hydrosilylation catalyst, in an amount sufficient to cure the composition.
2. The curable organopolysiloxane composition according to claim 1 , wherein a mole ratio of silicon-bonded hydrogen atoms provided by component (C 2 ) per silicon-bonded hydrogen atoms provided by component (C 1 ) is at least 2.
3. The curable organopolysiloxane composition according to claim 1 , further comprising:
(F) a hydrosilylation reaction inhibitor, in an amount sufficient to effect a pot-life of the composition.
4. A cured product obtained by curing the curable organopolysiloxane composition according to claim 1 .
5. The curable organopolysiloxane composition according to claim 1 , wherein all silicon-bonded groups other than alkenyl groups in component (A) are methyl groups.
6. The curable organopolysiloxane composition according to claim 1 , wherein component (D) is present in an amount of from 0.20 to 0.35 mass % of the composition.