SPONGE-FORMABLE SILICONE RUBBER COMPOSITION AND SILICONE RUBBER SPONGE

1 . A sponge-formable silicone rubber composition comprising:

(A) 100 parts by mass of a polyorganosiloxane having at least two silicon-bonded alkenyl groups per molecule;

(B) a polyorganosiloxane having at least two silicon-bonded hydrogen atoms per molecule, in an amount such that an amount of silicon-bonded hydrogen atoms in component (B) is from 0.4 to 20 moles per 1 mole of alkenyl groups in component (A);

(C) from 20 to 500 parts by mass of water;

(D) a thickening agent, in an amount of from 0.01 to 15 parts by mass per 100 parts by mass of component (C);

(E) from 0.1 to 15 parts by mass of an emulsifier;

(F) from 0.00001 to 2.0 parts by mass of a halogen-containing ion conductor of an alkali metal; and

(G) a hydrosilylation reaction catalyst, in an amount to accelerate a hydrosilylation reaction of the composition.

2 . The sponge-formable silicone rubber composition according to claim 1 , wherein component (D) is at least one type of thickening agent selected from the group consisting of inorganic thickening agents, cellulose fibers, water-soluble polymers, water-absorbent polymers, hydrophilic composites composed of the inorganic thickening agents and the water-soluble polymers, and hydrophilic composites composed of the inorganic thickening agents and the water-absorbent polymers.

3 . The sponge-formable silicone rubber composition according to claim 2 , wherein the inorganic thickening agent for component (D) is smectite clay.

4 . The sponge-formable silicone rubber composition according to claim 1 , wherein component (F) is at least one type of ion conductor selected from the group consisting of MBF 4 , MClO 4 , MPF 6 , MAsF 6 , MSbF 6 , MSO 3 CF 3 , MN(SO 2 CF 3 ) 2 , MSO 3 C 4 F 9 , MC(SO 2 CF 3 ) 3 , and MB(C 6 H 5 ) 4 , wherein M in the formulas is lithium or sodium.

5 . The sponge-formable silicone rubber composition according to claim 1 , further comprising (H) a hydrosilylation reaction inhibitor, in an amount of 0.001 to 5 parts by mass per 100 parts by mass of component (A).

6 . The sponge-formable silicone rubber composition according to claim 1 , further comprising (I) a reinforcing silica fine powder, in an amount of not greater than 30 parts by mass per 100 parts by mass of component (A).

7 . A silicone rubber sponge obtained by crosslinking the sponge-formable silicone rubber composition according to claim 1 by a hydrosilylation reaction and then removing water from the obtained silicone rubber, or removing water while crosslinking the composition by a hydrosilylation reaction.

8 . The silicone rubber sponge according to claim 7 , wherein the sponge is a silicone rubber sponge for a fixing member for an image forming device.

9 . The sponge-formable silicone rubber composition according to claim 3 , wherein component (F) is at least one type of ion conductor selected from the group consisting of MBF 4 , MClO 4 , MPF 6 , MAsF 6 , MSbF 6 , MSO 3 CF 3 , MN(SO 2 CF 3 ) 2 , MSO 3 C 4 F 9 , MC(SO 2 CF 3 ) 3 , and MB(C 6 H 5 ) 4 , wherein M in the formulas is lithium or sodium.

10 . The sponge-formable silicone rubber composition according to claim 9 , further comprising (H) a hydrosilylation reaction inhibitor, in an amount of 0.001 to 5 parts by mass per 100 parts by mass of component (A).

11 . The sponge-formable silicone rubber composition according to claim 10 , further comprising (I) a reinforcing silica fine powder, in an amount of not greater than 30 parts by mass per 100 parts by mass of component (A).

12 . The sponge-formable silicone rubber composition according to claim 5 , further comprising (I) a reinforcing silica fine powder, in an amount of not greater than 30 parts by mass per 100 parts by mass of component (A).