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US 4,906,697 AGranted
Rubber compositions for tire treads
AssigneeThe Yokohama Rubber Co., Ltd.
InventorsYasushi Kikuchi, Kazuyoshi Kayama, Takao Muraki
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Abstract
Rubber compositions for use in tire treads are disclosed which are essentially made up of natural and/or a selected class of polyisoprene rubbers of specified cis contents and a selected class of styrene-butadiene rubbers of specified styrene and 1,2-bond contents. The composition has a unique viscoelasticity curve, exhibiting sufficient wet skid resistance and adequate fuel saving.
Claims3
A rubber composition for use in tire treads which comprises:
- (a) natural rubber or synthetic polyisoprene rubber or both, said polyisoprene rubber having a cis content of not less than 80 percent;
- and
- (b) styrene-butadiene copolymer rubber having a styrene content in the range of 5 to 50 percent and a 1,2-bond content in the range of 60 to 73 percent, said copolymer rubber resulting from solution polymerization in the presence of an organic lithium compound catalyst, said composition having a bimodal loss factor-temperature curve as determined by dynamic viscoelasticity.
Dependencies are inferred from the claim text.