RUBBER COMPOSITION FOR SHOE SOLE AND RUBBER FOAM COMPOSITION

摘要

A rubber composition for shoe soles characterized by being obtained by compounding 100 parts by mass of a polymer ingredient which comprises 10-90 mass% vinyl/cis-polybutadiene rubber (A) comprising 1,4-cis-polybutadiene (a) and 1,2-polybutadiene crystal fibers (b) which have an average fiber length of 200 nm or shorter, an average aspect ratio of 10 or lower, and a melting point of 170°C or higher and in which the number of the crystal fibers having a fiber length of 200 nm or shorter is 90 or more per 25 µm², 10-50 mass% diene rubber (B) other than the rubber (A), and 2-50 mass% thermoplastic polymer (C) with 2-50 parts by mass of a rubber reinforcement (D). This rubber composition for shoe soles is lightweight, has a moderate hardness, is excellent in tensile strength, tear strength, wearing resistance, and gripping properties, and has excellent dimensional stability after foaming. It is suitable for use as the outer soles of shoes.