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AssigneeJsr Corporation
InventorsHiroshi Akema, Toshihiro Tadaki, Yoshiyuki Udagawa, Tomohisa Konno, Takafumi Fueki, Hajime Kondou
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It is an object of the present invention to provide a rubber composition which can give a vulcanized rubber with low rolling resistance and excellent wet skid resistance and wear resistance, which is particularly useful for automobile tire treads and the like. The rubber composition of the invention comprises (1) a crosslinked rubber particle containing, as repeating units, 40 to 79.99% by weight of a monomer unit formed by a conjugated diene such as 1,3-butadiene, 20 to 50% by weight of a monomer unit formed by an aromatic vinyl monomer such as styrene and 0.01 to 10% by weight of a monomer unit formed by a monomer having at least two polymerizable unsaturated groups such as divinylbenzene, and (2) a conjugated diene/aromatic vinyl copolymeric rubber whose vinyl content of the conjugated diene monomer unit is 10 to 30% and whose 1,4-trans bond content is more than 55%, such as styrene-butadiene copolymeric rubber. The crosslinked rubber particle may also contain a repeating unit composed of a monomer having one polymerizable unsaturated group and carboxylic group, hydroxyl group and/or epoxy group.
A rubber composition characterized in that it comprises [1A] a crosslinked rubber particle containing, as repeating units, (a1) 40 to 79.99% by weight of a conjugated diene monomer unit, (a2) 20 to 50% by weight of an aromatic vinyl monomer unit and (a3) 0.01 to 10% by weight of a monomer unit formed by a monomer having at least two polymerizable unsaturated groups with respect to 100% by weight of total of (a1), (a2) and (a3), and [2A] a conjugated diene/aromatic vinyl copolymeric rubber wherein vinyl bond content of conjugated diene unit is 10 to 30% by weight and 1,4-trans bond content is exceeding 55% by weight.
A rubber composition characterized in that it comprises [1B] a crosslinked rubber particle containing, as repeating units, (b1) 40 to 99.89% by weight of a conjugated diene monomer unit, (b2) 0 to 50% by weight of an aromatic vinyl monomer unit, (b3) 0.01 to 10% by weight of a monomer unit formed by a monomer having at least two polymerizable unsaturated groups and (b4) 0.1 to 30% by weight of a monomer unit formed by a monomer having one polymerizable unsaturated group and at least one functional group selected from the group consisting of carboxylic group (CO2H and/or CO2−), hydroxyl group and epoxy group with respect to 100% by weight of total of (b1), (b2), (b3) and (b4), and [2B] a conjugated diene/aromatic vinyl copolymeric rubber wherein vinyl bond content of conjugated diene unit is 10 to 30% by weight and 1,4-trans bond content is exceeding 55% by weight.
Dependencies are inferred from the claim text.