Compositions for tires
AssigneeThe Toyo Rubber Industry Co., Ltd.
InventorsTatsuo Sakashita, Takyya Okazaki, Masanori Kan
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Abstract
A composition for tires containing at least 30% star shaped random styrene-butadiene copolymer obtained by solution polymerization, having a styrene content of less than 20% and more than 10% and a vinyl content of less than 50% and more than 40%, the composition value X of said copolymers being in a range of 26 to 39 obtained by using the equation; ##EQU1## wherein BR is the butadiene component, the glass transition temperature being a single one below -50.degree. C. and lower than estimated glass transition temperature following Gordon-Taylor equation by 5.degree. to 10.degree. C. and a cured composition showing loss modulus of lower than 1.times.10.sup.-7 dyn/cm.sup.2 and a ratio of rolling resistance to wet grip being smaller than 0.82.
Claims3
A tire tread composition for reducing energy consumption containing at least 30% star shaped random styrene-butadiene copoymer obtained by solution polymerization, and said star shaped random styrene-butadiene copolymer having a styrene content which is less than 20% and more than 10% and a vinyl content which is less than 50% and more than 40% and wherein the composition value X of said styrene-butadiene copolymers obtained by the following equation being in a range of 26 to 39:
- ##EQU4## wherein BR is the butadiene component, and said copolymer having only one glass transition temperature below -50.degree. C. and being lower than estimated glass transition temperature following Gordon-Taylor equation by 5.degree. to 10.degree. C.
Dependencies are inferred from the claim text.