| 摘要 |
<p>PURPOSE:To reduce the weight of a tire of save fuel costs of a car by arranging a wedge-shaped buffer layer of a predetermined structure and of a predetermined composition under a belt or between the belt and a carcass at each end of the belt which consists of two strain layers disposed at a specific angle relative to a circumferential line of the tire and a breaker layer. CONSTITUTION:A belt 2 consists of two strain layers 2a, 2b having cords thereof intersecting a circumferential line of the tire at an angle of 30 deg. or less and intersecting each other with the circumferential line put between them, and a breaker layer 2c interposed between the strain layers 2a, 2b and having cords arranged at an angle of 30 deg. or less relative to the circumference of the tire. A pair of wedge-shaped buffer layers 3 are disposed under the belt 2, that is, between the belt 2 and a carcass 1 at opposite sides of the belt 2. The buffer layer 3 is made of a rubber composition which contains as a principal component a polymer of cis-1,4- and syn-1,2-polybutadienes or a blended rubber containing 10wt% or more of the polymer. The polymer contains 6-20wt% of a microcrystalline syn-1,2-structure, and 40wt% or more thereof is crystalline. The polymer is further in short filaments having the average diameter of 0.05-1mum and the average length of 0.8-10mum. The constitution thus reduces the weight of a tire and thereby saves fuels costs of a car.</p> |
