Vibration-damping rubber composition, and liquid-filled vibration-damping rubber device

1. A vibration-damping rubber composition to be used as a material for a rubber member of a liquid-filled vibration-damping rubber device in which a glycol liquid is sealingly contained, the rubber composition comprising:

(A) a chloroprene rubber as a major component; and

(B) an aromatic hydrocarbon plasticizer having a viscosity of 9 to 70 mm 2 /s when measured at a temperature of 98.9° C. in conformity with JIS K2283.

2. The vibration-damping rubber composition according to claim 1 , wherein the aromatic hydrocarbon plasticizer (B) is present in a proportion of 3 to 30 parts by weight based on 100 parts by weight of the chloroprene rubber (A).

3. The vibration-damping rubber composition according to claim 1 , wherein the chloroprene rubber (A) is at least one selected from the group consisting of a xanthogen-modified chloroprene rubber, a mercapto-modified chloroprene rubber and a sulfur-modified chloroprene rubber.

4. The vibration-damping rubber composition according to claim 1 , wherein the aromatic hydrocarbon plasticizer (B) comprises a carbon derived from an aromatic hydrocarbon in a proportion of at least 32% based on an overall carbon content according to a carbon type analysis.

5. The vibration-damping rubber composition according to claim 1 , further comprising at least one reinforcing material selected from the group consisting of carbon black, calcium carbonate, talc and clay.

6. The vibration-damping rubber composition according to claim 1 , further comprising a reinforcing material in a proportion of 5 to 100 parts by weight based on 100 parts by weight of the chloroprene rubber (A).

7. The vibration-damping rubber composition according to claim 1 , further comprising at least one crosslinking agent selected from the group consisting of zinc oxide, magnesium oxide and lead oxide.

8. The vibration-damping rubber composition according to claim 1 , further comprising a crosslinking agent in a proportion of 0.5 to 5 parts by weight based on 100 parts by weight of the chloroprene rubber (A).

9. The vibration-damping rubber composition according to claim 1 , further comprising at least one vulcanization accelerating agent selected from the group consisting of a thiazole vulcanization accelerating agent, a sulfenamide vulcanization accelerating agent, a thiuram vulcanization accelerating agent, an aldehyde ammonia vulcanization accelerating agent, an aldehyde amine vulcanization accelerating agent, a guanidine vulcanization accelerating agent and a thiourea vulcanization accelerating agent.

10. The vibration-damping rubber composition according to claim 1 , further comprising a vulcanization accelerating agent in a proportion of 0.1 to 10 parts by weight based on 100 parts by weight of the chloroprene rubber (A).

11. The vibration-damping rubber composition according to claim 1 , further comprising at least one vulcanization acceleration assisting agent selected from the group consisting of zinc oxide, active zinc white and stearic acid.

12. The vibration-damping rubber composition according to claim 1 , further comprising a vulcanization acceleration assisting agent in a proportion of 0.1 to 10 parts by weight based on 100 parts by weight of the chloroprene rubber (A).

13. The vibration-damping rubber composition according to claim 1 , further comprising at least one anti-aging agent selected from the group consisting of a carbamate anti-aging agent, a phenylenediamine anti-aging agent, a phenol anti-aging agent, a diphenylamine anti-aging agent, a quinoline anti-aging agent, an imidazole anti-aging agent and a wax.

14. The vibration-damping rubber composition according to claim 1 , further comprising an anti-aging agent in a proportion of 0.1 to 10 parts by weight based on 100 parts by weight of the chloroprene rubber (A).

15. The vibration-damping rubber composition according to claim 1 , further comprising at least one acid accepting agent selected from the group consisting of magnesium oxide, a hydrotalcite, a zeolite, aluminum hydroxide, calcium oxide, calcium hydroxide, aluminum oxide, calcium carbonate, calcium silicate, basic silicon dioxide, magnesium hydroxide and zinc oxide.

16. The vibration-damping rubber composition according to claim 1 , further comprising an acid accepting agent in a proportion of 1 to 10 parts by weight based on 100 parts by weight of the chloroprene rubber (A).

17. A liquid-filled vibration-damping rubber device comprising:

a rubber member which defines a sealed space therein and is deformable according to inputted vibrations; and

a glycol liquid sealingly contained in the sealed space;

wherein the rubber member comprises the vibration-damping rubber composition according to claim 1 .

18. The liquid-filled vibration-damping rubber device according to claim 17 , wherein the sealingly contained glycol liquid comprises at least one of ethylene glycol (EG) and propylene glycol (PG).

19. The liquid-filled vibration-damping rubber device according to claim 17 , wherein the sealingly contained glycol liquid is a mixture prepared by mixing ethylene glycol (EG) and propylene glycol (PG) wherein a mixing weight ratio of EG/PG is from 7/3 to 5/5.

20. The vibration-damping rubber composition according to claim 1 , wherein the aromatic hydrocarbon plasticizer (B) comprises a carbon derived from a paraffinic carbon in a proportion of no more than 31% based on the overall carbon content according to the carbon type analysis.

21. The vibration-damping rubber composition according to claim 1 , further comprising a sulfenamide vulcanization acceleration agent.