| 摘要 |
PURPOSE:To provide the titled rubber suitable for pneumatic tire tread, comprising, as a matrix, random copolymer from styrene and 1,3-butadiene with the primary characteristics such as bonded styrene amount and cis-1,4-bond content representing each specific value. CONSTITUTION:The objective rubber can be obtained by incorporating (A) 100pts.wt. of a copolymer prepared by random copolymerization between styrene and 1,3-butadiene with (B) 10-20pts.wt. of carbon black and (C) 0.5-5pts.wt. of curing agent. Said copolymer has the following characteristics: (1) bonded styrene content ... 12-35wt% (2) 1,2-bond content in butadiene section ...30-45wt% (3) cis-1,4-bond content ... <=23wt% (4) trans-1,4-bond content ...>=42wt% (5) difference between trans-1,4-bond and cis-1,4-bond ... >=8wt% (6) 65<=1.7 X bonded styrene (wt%) + 1,2-bond (wt%) <=100 (7) ratio: weight- average molecular weight/number-average molecular weight <=2.3.
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