Vibration damping rubber member and process of producing the same

A process of producing a vibration damping rubber member, characterized by:

• evenly mixing together an unvulcanized rubber material A which enables the vibration damping rubber member to exhibit a low degree of dynamic spring stiffness, an unvulcanized rubber material B which enables the vibration damping rubber member to have a high vibration damping effect, and a vulcanizing agent capable of vulcanizing only said unvulcanized rubber material B;
• heating a mixture of said unvulcanized rubber materials A and B and said vulcanizing agent, to vulcanize said unvulcanized rubber material B such that fine particles of the vulcanized rubber material B, having an average size of 0.1 to 100 μm, are dispersed in said unvulcanized rubber material A;
• adding to said mixture a vulcanizing agent capable of vulcanizing said unvulcanized rubber material A;
• and forming a thus obtained mixture into a desired shape, and heating the formed mixture to vulcanize said unvulcanized rubber material A, for obtaining said vibration damping rubber member having an island-sea structure in which fine particles of the vulcanized rubber material B are dispersed as a dispersed phase in a matrix phase of the vulcanized rubber material A.