Curable silicone composition that provides a highly transparent cured silicone material
View Patent ↗A curable silicone composition comprises (A) (A-1) an alkenyl-containing dialkylpolysiloxane and a viscosity of at least 1,000 mPa·s to not more than 20,000 mPa·s and (A-2) an alkenyl-containing, resin-form organopolysiloxane that comprises the SiO 4/2 unit, R 1 2 R 2 SiO 1/2 unit, and R 1 3 SiO 1/2 unit wherein R 1 is alkyl and R 2 is alkenyl, that contains from 2.5 to 5.0 mass % alkenyl group, and that has a ratio for the total number of moles of R 1 2 R 2 SiO 1/2 and R 1 3 SiO 1/2 units to 1 mole of the SiO 4/2 unit in the range from 0.70 to 1.10; (B) an organopolysiloxane that contains at least 0.9 mass % silicon-bonded hydrogen; and (C) a hydrosilylation reaction catalyst. The curable composition provides a bending-tolerant and highly transparent cured silicone material that has a hardness in the range from 80 to 95, and a parallel light transmittance at 200° C. of a value that is at least 99% of the parallel light transmittance at 25° C.
1. A curable silicone composition that provides a bending-tolerant and highly transparent cured silicone material, said composition comprising
(A) 100 mass parts of an alkenyl-containing organopolysiloxane comprising
(A-1) a dialkylpolysiloxane that has an average of at least two alkenyl groups in each molecule and a viscosity at 25° C. of at least 1,000 mPa·s to not more than 20,000 mPa·s, at from 50 mass % to not more than 70 mass % of component (A), and
(A-2) an alkenyl-containing, resin-form organopolysiloxane that comprises the SiO 4/2 unit, R 1 2 R 2 SiO 1/2 unit, and R 1 3 SiO 1/2 unit wherein R 1 is C 1-10 alkyl and R 2 is alkenyl, that contains from 2.5 to 5.0 mass % alkenyl group, and that has a ratio for the total number of moles of R 1 2 R 2 SiO 1/2 and R 1 3 SiO 1/2 units to 1 mole of the SiO 4/2 unit in the range from 0.70 to 1.10, at from 30 mass % to not more than 50 mass % of component (A);
(B) an organopolysiloxane that contains at least 0.9 mass % silicon-bonded hydrogen wherein the silicon-bonded groups other than the silicon-bonded hydrogen are C 1-10 alkyl, in an amount that provides 0.8 to 2 moles silicon-bonded hydrogen in this component per 1 mole of the total alkenyl in component (A); and
(C) a hydrosilylation reaction catalyst in a catalytic quantity,
and provides a bending-tolerant and highly transparent cured silicone material that has a hardness measured using the type A durometer specified in JIS K 6253 in the range from 80 to 95, an elongation as specified in JIS K 6251 of at least 30%, a parallel light transmittance at 25° C. measured in accordance with JIS K 7105 on a 6 mm optical path length of at least 90%, and the parallel light transmittance at 200° C. of a value that is at least 99% of the parallel light transmittance at 25° C.
2. The curable silicone composition according to claim 1 , wherein component (B) is an organopolysiloxane comprising
(B-1) an organopolysiloxane that contains at least 0.9 mass % silicon-bonded hydrogen and that comprises the SiO 4/2 unit and HR 3 2 SiO 1/2 unit wherein R 3 is C 1-10 alkyl, at 50 to 100 mass % of component (B), and
(B-2) a straight-chain organopolysiloxane that contains at least 0.9 mass % silicon-bonded hydrogen wherein the silicon-bonded groups other than the silicon-bonded hydrogen are C 1-10 alkyl, at 0 to 50 mass % of component (B).
3. A bending-tolerant and highly transparent cured silicone material provided by the thermosetting of a curable silicone composition comprising
(A) 100 mass parts of an alkenyl-containing organopolysiloxane comprising
(A-1) a dialkylpolysiloxane that has an average of at least two alkenyl groups in each molecule and a viscosity at 25° C. of at least 1,000 mPa·s to not more than 20,000 mPa·s, at from 50 mass % to not more than 70 mass % of component (A), and
(A-2) an alkenyl-containing, resin-form organopolysiloxane that comprises the SiO 4/2 unit, R 1 2 R 2 SiO 1/2 unit, and R 1 3 SiO 1/2 unit wherein R 1 is C 1-10 alkyl and R 2 is alkenyl, that contains from 2.5 to 5.0 mass % alkenyl group, and that has a ratio for the total number of moles of R 1 2 R 2 SiO 1/2 and R 1 3 SiO 1/2 units to 1 mole of the SiO 4/2 unit in the range from 0.70 to 1.10, at from 30 mass % to not more than 50 mass % of component (A);
(B) an organopolysiloxane that contains at least 0.9 mass % silicon-bonded hydrogen wherein the silicon-bonded groups other than the silicon-bonded hydrogen are C 1-10 alkyl, in an amount that provides 0.8 to 2 moles silicon-bonded hydrogen in this component per 1 mole of the total alkenyl in component (A); and
(C) a hydrosilylation reaction catalyst in a catalytic quantity,
and has a hardness measured using the type A durometer specified in JIS K 6253 in the range from 80 to 95, an elongation as specified in JIS K 6251 of at least 30%, a parallel light transmittance at 25° C. measured in accordance with JIS K 7105 on a 6 mm optical path length of at least 90%, and a value for the parallel light transmittance at 200° C. that is at least 99% of the parallel light transmittance at 25° C.
4. The bending-tolerant and highly transparent cured silicone material according to claim 3 , wherein component (B) is an organopolysiloxane comprising
(B-1) an organopolysiloxane that contains at least 0.9 mass % silicon-bonded hydrogen and that comprises the SiO 4/2 unit and HR 3 2 SiO 1/2 unit wherein R 3 is C 1-10 alkyl, at 50 to 100 mass % of component (B), and
(B-2) a straight-chain organopolysiloxane that contains at least 0.9 mass % silicon-bonded hydrogen wherein the silicon-bonded groups other than the silicon-bonded hydrogen are C 1-10 alkyl, at 0 to 50 mass % of component (B).
5. A cured silicone composite characteristically comprising a substrate that forms a single article with a cured silicone layer that is provided by the thermosetting of a curable silicone composition according to claim 1 .
6. A cured silicone composite obtained by coating the curable silicone composition according to claim 1 on a substrate and then thermosetting the curable silicone composition.