NEW COBALT COMPOUND, RUBBER COMPOSITION, RUBBER-STEEL CORD COMPOSITE MATERIAL, AND PNEUMATIC TIRE

摘要

PROBLEM TO BE SOLVED: To obtain a new cobalt compound, a rubber composition containing the compound, and to provide a rubber-steel cord composite material, a pneumatic tire using the composite material, and to obtain an adhesion accelerator which shortens as adhesion time and gives excellent adhesion durability. SOLUTION: The cobalt compound is represented by formula (1) (R1 and R2 are each independently a 6 to 24C alkyl, an aryl, allyl, or an aralkyl, provided that R1 and R2 may be the same groups, respectively). The rubber composition comprises 100 pts.wt. of a rubber component, 20 to 90 pts.wt. of carbon black, 0.1 to 2.0 pts.wt. of the cobalt compound of formula (1), and 1.0 to 10 pts.wt. of sulfur. The rubber-steel cord composite material comprises the rubber composition and brass-plated steel cords. The pneumatic tire uses the composite material.