| 摘要 |
PURPOSE: A pneumatic radial tire is provided to prevent crack in the edge of a belt, and to improve endurance of the belt by increasing the modulus of edge tape rubber and reducing shearing stress between belt layers of the belt edge. CONSTITUTION: The thickness of a rubber tape is formed to be within the ranges of 0.3-1.5mm, and the width of the rubber tape is 10-80mm. The edges of a belt layer are covered with the rubber tape in a pneumatic radial tire. The modulus of the belt edge tape divided by the modulus of the belt topping rubber(1) is over 1.15. The tape rubber(2) of the belt edge is composed of carbon black of 45-75wt% having the iodine adsorption number of 70-100mg/g to rubber of 100wt% and DBP(dibutyl phthalate) absorption of 60-100ml/100g, sulfur of 3-10wt%, accelerant of 0.5-2.0wt%, and resin of 1-10wt% including 10-60% cresol resin having a softening point of 80-100deg.C. The amount of carbon black is increased in the belt edge tape rubber, and sulfur and accelerant are added. The adhesive force is improved, and the modulus is increased with applying cresol resin. Shearing stress between the belt layers is reduced with increasing the modulus of the belt edge tape rubber. The endurance of the belt is improved with preventing crack in the edge of the belt.
|
