| 摘要 |
<p>Tyres consists of (i) a toroidal carcass made of rubberised cord layers in the radial plane of the tyre or in a plane inclined at a small angle to the radial plane, and (ii) a rubberised steel cord girdle over the upper part of the carcass. Girdle consists of three layers two of which are traction-resistant and inclined at an angle of 30 degrees to the circumference line of the tyre, and cross over the cords of both layers at the circumference line of the tyre. The uppermost breaker layer is made of cord and placed at an angle of 30 degrees, pref. 10-25 degrees, to the circumference line of the tyre. Pairs of wedge-shaped, shock-absorbing layers are provided between the lower surfaces of both sides of the girdle and the carcass. These are made of a rubber mixture which is either (a) a polybutadiene rubber comprising a block-or graft polymer of cis-1; 4-polybutadiene with syndiotactic (syn)-1; 2-polybutadiene, contg. 6-20% syn-1; 2-isomer at least 40% of which is crystalline and being in the form of short fibres of average thickness 0.05-1 mu m and average length of 0.8-10 mu m., - or (b) a rubber contg. at least 10% polybutadiene, the remainder being natural rubber or another diene rubber. Tyres are lightweight and thus afford fuel economy.</p> |
