Provided are: a rubber-reinforcing fiber, in which adhesion between a rubber and a fiber is enhanced and which is thereby capable of further improving the durability than before when used as a reinforcing material; a rubber-fiber composite; and a pneumatic tire using the same. The rubber-reinforcing fiber includes a core-sheath type composite fiber whose core portion is composed of a high-melting-point resin (A) having a melting point of 150°C or higher and sheath portion is composed of a resin material (B) having a melting point lower than that of the high-melting point resin (A). The resin material (B) contains an olefin-based polymer (X) and a vulcanization accelerator (F).
本文提供了一种橡胶补强纤维,该纤维增强了橡胶和纤维之间的粘附力,因此在用作补强材料时,其耐用性比以前有了进一步提高;一种橡胶纤维复合材料;以及一种使用该纤维的充气轮胎。橡胶增强纤维包括芯鞘型复合纤维,其芯部由熔点为 150°C 或更高的高熔点
树脂 (A) 组成,鞘部由熔点低于高熔点
树脂 (A) 的
树脂材料 (B) 组成。
树脂材料(B)含有烯烃基聚合物(X)和
硫化
促进剂(F)。