Sulfur-containing conjugated diolefin copolymer rubber, and rubber composition comprising the same

A sulfur-containing copolymer rubber composed of a conjugated diolefin and an aromatic vinyl compound, wherein:

• (1) the copolymer rubber contains 0.01 mmol % or more of sulfur that is bound to the rubber,
• (2) the aromatic vinyl compound polymerization unit content is 5 weight % or more and less than 45 weight % relative to the amount of the copolymer rubber,
• (3) the content of a vinyl bond (1,2-bond) in the conjugated diolefin polymerization unit is 30 mol % or more relative to the amount of conjugated diolefin polymerization units, and when copolymerizing the conjugated diolefin and the aromatic vinyl compound, the reaction is terminated using at least one type of a compound selected from polymerization terminators with the following formulas (I) through (III):
• wherein, n is between 0 and 2;
• R′ and R″ independently represent alkyl groups with between 1 and 4 carbon atoms;
• R1 represents an alkylene group with between 1 and 8 carbon atoms;
• R2, R3 and R4 independently represent hydrogen atoms, alkyl groups with between 1 and 18 carbon atoms, or cycloalkyl groups with between 3 and 10 carbon atoms, or phenyl groups;
• and A represents an oxygen atom,
• wherein, n is between 0 and 2;
• R′ and R″ independently represent alkyl groups with between 1 and 4 carbon atoms;
• R1 and R4 independently represent alkylene groups with between 1 and 8 carbon atoms;
• R2, R3, R5, and R6 independently represent hydrogen atoms, alkyl groups with between 1 and 18 carbon atoms, or phenyl groups;
• R7 represents an alkylene group between 1 and 10 carbon atoms, or a cycloalkylene with between 3 and 10 carbon atoms, or a phenylene group;
• and A and A′ represent oxygen atoms,
• wherein, n is between 0 and 2;
• R′ and R″ independently represent alkyl groups with between 1 and 4 carbon atoms;
• R1, R4 and R7 independently represent alkylene groups with between 1 and 8 carbon atoms;
• R2, R3, R5, R6, R8 and R9 independently represent hydrogen atoms, or groups selected from alkyl groups with between 1 and 8 carbon atoms, or phenyl groups;
• and A, A′, and A″ independently represent oxygen atoms.