Conjugated diene rubber, rubber composition, crosslinked rubber, tire, and process for production of conjugated diene rubber

摘要

For a tire excellent in strength, low-heat buildup property, wet grip property, and driveability, and a rubber composition and a conjugated diene rubber for the tire, a conjugated diene rubber of the present invention includes 5 wt % or more of a structure that 3 or more conjugated diene polymer chains are bound via a denaturing agent, obtained by reaction of each chain and the agent, each chain being that at least one of terminals is an isoprene block having 70 wt % or more of an isoprene monomer unit, and the other is an active terminal, the agent having, per molecule, at least one of an epoxy group(s) and a hydrocarbyloxysilyl group(s), and being that a total number of the epoxy group(s) and hydrocarbyloxy groups in the hydrocarbyloxysilyl group(s) per molecule is 3 or more.

主权项

1. A conjugated diene rubber comprising:
such a structure that not less than 3 conjugated diene polymer chains are bound to each other via a denaturing agent, an amount of the structure in the conjugated diene rubber being not less than 5% by weight, the structure being obtained by causing the not less than 3 conjugated diene polymer chains and the denaturing agent to be reacted with each other, each of the not less than 3 conjugated diene polymer chains having (i) at least one of terminals which is an isoprene block having not less than 70% by weight of an isoprene monomer unit, (ii) the other one of terminals which is an active terminal, and (iii) a part other than the isoprene block having 0% by weight or more but less than 70% by weight of an isoprene monomer unit, each of the not less than 3 conjugated diene polymer chains being such that the part other than the isoprene block is a homopolymer chain of a conjugated diene monomer, or a copolymer chain of a conjugated diene monomer and an aromatic vinyl monomer, wherein a weight ratio of a conjugated diene monomer unit to an aromatic vinyl monomer unit (the conjugated diene monomer unit: the aromatic vinyl monomer unit) is in a range of 100:0 to 50:50, and a polymerization type of the copolymer chain of the conjugated diene monomer and the aromatic vinyl monomer is a random type, the denaturing agent (I) having, per molecule, at least one of (1) one or more epoxy groups and (2) one or more hydrocarbyloxysilyl groups, and (II) being such that a total number of the number of the one or more epoxy groups per molecule and the number of hydrocarbyloxy groups in the one or more hydrocarbyloxysilyl groups per molecule is not less than 3.