Rubber composition, vibration-isolating rubber and vibration-isolating mount

摘要

The object of the present invention is to provide a rubber composition which gives a vibration-isolating rubber which is excellent in vibration-isolating property, a vibration-isolating rubber formed by the rubber composition and a vibration-isolating mount. The present rubber composition contains 5 to 40 parts by weight of a styrene-butadiene-based copolymer rubber having a weight-average molecular weight of 200,000 or less and a glass transition temperature of -35°C or higher, and 95 to 60 parts by weight of a diolefin-based rubber having a weight-average molecular weight exceeding 200,000 and a glass transition temperature of -20°C or lower, based on 100 parts by weight of the total amount of both. A vibration-isolating rubber comprising this composition has a performance that a relationship between a dynamic-to-static modulus ratio (Kd/Ks) which is a ratio of a dynamic spring constant (Kd) and a static spring constant (Ks), and a loss factor (tanδ) is shown by the equation (1): Kd/Ks ≦ 20tanδ - 1.8 (1). This vibration-isolating rubber is used for a vibration-isolating mount.