| 摘要 |
PROBLEM TO BE SOLVED: To provide natural rubber having excellent crack propagation resistance while keeping processability, a rubber composition containing the natural rubber, and a tire obtained by using the rubber composition.SOLUTION: Natural rubber is obtained by treating natural rubber latex or natural rubber and contains a higher-molecular-weight component of ≥10 mass% and <20 mass%. The higher-molecular-weight component has ≥5,000,000 molecular weight, when the molecular weight is measured by the following measurement method, and 0.840 of a branch index (g) when the higher-molecular-weight component has 5,000,000 molecular weight. The natural rubber is used in the rubber composition and the tire. The measurement method comprises the steps of: centrifuging a solution of the natural rubber by 10,000-1,000,000 G centrifugal acceleration; and measuring a soluble component of the centrifuged solution by using a multi-angle light scattering detector and a field flow fractionation device. |
