Heat-Curable Silicone Rubber Composition For Rubber Laminate

Abstract

A heat-curable silicone rubber composition for a rubber laminate composed of a silicone-rubber layer and a rubber layer of a material other than silicone, the composition comprising: an alkenyl-containing diorganopolysiloxane (A) which comprises: 50 to 99 mass % of a diorganopolysiloxane (A1) that contains alkenyl groups, is capped at molecular terminals with alkenyl-containing organosilyl groups, and is free of alkenyl groups in side molecular chains; 1 to 50 mass % of an alkenyl-containing diorganopolysiloxane (A2) having two or more alkenyl groups in a side molecular chain; a fine silica powder (B); an organohydrogenpolysiloxane (C) having in one molecule at least two silicon-bonded hydrogen atoms; and an organic peroxide (D).

1 . A heat-curable silicone rubber composition for a rubber laminate composed of a silicone-rubber layer and a rubber layer of a material other than silicone, the composition comprising:
 100 parts by mass of an alkenyl-containing diorganopolysiloxane (A) which comprises:   50 to 99 mass % of an alkenyl-containing diorganopolysiloxane (A1) that is capped at molecular terminals with alkenyl-containing organosilyl groups, is free of alkenyl groups in side molecular chains, and has a degree of polymerization in the range of 2,500 to 100,000;   1 to 50 mass % of an alkenyl-containing diorganopolysiloxane (A2) having two or more alkenyl groups in side molecular chains and having a degree of polymerization in the range of 2,500 to 100,000;   10 to 100 parts by mass of a fine silica powder (B) having specific surface area in the range of 50 m 2 /g to 400 m 2 /g;   0.1 to 10 parts by mass of an organohydrogenpolysiloxane (C) having in one molecule at least two silicon-bonded hydrogen atoms; and   0.1 to 5 part by mass of an organic peroxide (D).   
     
     
         2 . The heat-curable silicone rubber composition for a rubber laminate according to  claim 1 , wherein the rubber laminate comprises a silicone-rubber layer and a fluororubber layer. 
     
     
         3 . The heat-curable silicone rubber composition for a rubber laminate according to  claim 1 , wherein the content of alkenyl groups in constituent (A2) ranges from 0.4 to 1.8 mass %. 
     
     
         4 . (canceled) 
     
     
         5 . (canceled) 
     
     
         6 . The heat-curable silicone rubber composition for a rubber laminate according to  claim 2 , wherein the content of alkenyl groups in constituent (A2) ranges from 0.4 to 1.8 mass %. 
     
     
         7 . The heat-curable silicone rubber composition for a rubber laminate according to  claim 1 , wherein the degree of polymerization of constituent (A1) is in the range of 3,000 to 20,000. 
     
     
         8 . The heat-curable silicone rubber composition for a rubber laminate according to  claim 1 , wherein the degree of polymerization of constituent (A2) is in the range of 3,000 to 20,000. 
     
     
         9 . The heat-curable silicone rubber composition for a rubber laminate according to  claim 1 , wherein the alkenyl groups of constituent (A1) are vinyl. 
     
     
         10 . The heat-curable silicone rubber composition for a rubber laminate according to  claim 3 , wherein, in addition to the alkenyl groups, constituent (A1) contains other silicon-bonded groups which are alkyl groups. 
     
     
         11 . The heat-curable silicone rubber composition for a rubber laminate according to  claim 10 , wherein more than 50 mole % of silicon-bonded groups in constituent (A1) are the alkyl groups. 
     
     
         12 . The heat-curable silicone rubber composition for a rubber laminate according to  claim 11 , wherein the alkyl groups are methyl groups. 
     
     
         13 . The heat-curable silicone rubber composition for a rubber laminate according to  claim 3 , wherein, in addition to the alkenyl groups, constituent (A2) contains other silicon-bonded groups which are alkyl groups. 
     
     
         14 . The heat-curable silicone rubber composition for a rubber laminate according to  claim 13 , wherein more than 50 mole % of silicon-bonded groups in constituent (A2) are the alkyl groups. 
     
     
         15 . The heat-curable silicone rubber composition for a rubber laminate according to  claim 14 , wherein the alkyl groups are methyl groups. 
     
     
         16 . The heat-curable silicone rubber composition for a rubber laminate according to  claim 1 , wherein the fine silica powder has a specific surface area in the range of 100 m 2 /g to 400 m 2 /g. 
     
     
         17 . A heat-curable silicone rubber composition for a rubber laminate composed of a silicone-rubber layer and a rubber layer of a material other than silicone, the composition comprising:
 100 parts by mass of an alkenyl-containing diorganopolysiloxane (A) which comprises:   60 to 98 mass % of an alkenyl-containing diorganopolysiloxane (A1) that is capped at molecular terminals with alkenyl-containing organosilyl groups, is free of alkenyl groups in side molecular chains, and has a degree of polymerization in the range of 2,500 to 100,000;   2 to 40 mass % of an alkenyl-containing diorganopolysiloxane (A2) having two or more alkenyl groups in side molecular chains and having a degree of polymerization in the range of 2,500 to 100,000;   10 to 100 parts by mass of a fine silica powder (B) having specific surface area in the range of 50 m 2 /g to 400 m 2 /g;   0.1 to 10 parts by mass of an organohydrogenpolysiloxane (C) having in one molecule at least two silicon-bonded hydrogen atoms; and   0.1 to 5 part by mass of an organic peroxide (D).