SILICONE RUBBER COMPOSITION AND SILICONE RUBBER CROSS-LINKED BODY, AND INTEGRALLY MOLDED BODY AND METHOD FOR PRODUCING INTEGRALLY MOLDED BODY
Provided is a silicone rubber composition that has excellent storage stability and an improved post-curing compression set, and a silicone rubber cross-linked body made from the silicone rubber composition. A silicone rubber composition contains (a) an organopolysiloxane, (b) a cross-linking agent, and (c) a microcapsule type catalyst that is made from resin microparticles encapsulating a cross-linking catalyst, wherein the resin of (c) is one of a thermosetting resin that is thermally cured in the presence of the cross-linking catalyst and a thermosetting resin that is thermally cured in the absence of the cross-linking catalyst.
1 . A silicone rubber cross-linked body comprising a silicone rubber composition comprising:
(a) an organopolysiloxane;
(b) a cross-linking agent; and
(c) a microcapsule type catalyst that comprises resin microparticles encapsulating a cross-linking catalyst,
wherein the resin of the microcapsule type catalyst (c) comprises a thermosetting resin that is thermally cured in the presence of the cross-linking catalyst or in the absence of the cross-linking catalyst, and softens at a temperature lower than thermal curing temperatures of the organopolysiloxane (a) and the resin of the microcapsule type catalyst (c),
the resin of the microcapsule type catalyst (c) has a glass transition temperature of 40° C. or higher and 130° C. or lower,
the resin microparticles of the microcapsule type catalyst (c) have an average particle diameter of 2 μm or larger and 10 μm or smaller,
the content of the microcapsule type catalyst in the silicone rubber composition is within a range of 0.01 to 5.0 parts by mass with respect to 100 parts by mass of the organopolysiloxane (a), and
the silicone rubber composition after thermal curing has a compression set of 40% or less in a test of 150° C.×70 hours, and 60% or less in a test of 175° C.×22 hours measured in accordance with JIS K6262 at 25% compression.
2 . The silicone rubber cross-linked body according to claim 1 , wherein the resin of the microcapsule type catalyst (c) is a polyvinyl butyral resin.
3 . The silicone rubber cross-linked body according to claim 1 , wherein the resin of the microcapsule type catalyst (c) is an unsaturated polyester resin.
4 . The silicone rubber cross-linked body according to claim 1 , wherein the resin of the microcapsule type catalyst (c) is an epoxy resin.