Composition for adhesion of rubber to reinforcing materials

A vulcanizable rubber composition consisting essentially of (A) a rubber comprising natural rubber, polybutadiene, polyisoprene, ethylenepropylene terpolymer rubber, butadiene-styrene copolymer rubber, butadiene-acrylonitrile copolymer rubber, chloroprene rubber, chlorosulfonated polyethylene or a mixture thereof;

• (B) a sulfur vulcanizing agent;
• and (C) from about 1 to 10 parts by weight, per hundred parts by weight of rubber, of a compound selected from the group consisting of (1) compounds of the formula:
• ##STR9## wherein R and R' are individually lower (C.sub.1 -C.sub.4) alkyl, aryl (C.sub.6 -C.sub.10) or cycloalkyl having 5 or 6 carbon atoms in the ring;
• (2) compounds of the formula:
• ##STR10## wherein R.sup.2 and R.sup.3 are individually alkyl (C.sub.1 -C.sub.8) aryl (C.sub.6 -C.sub.10), cycloalkyl having 5 or 6 carbon atoms in the ring, cyano, carboxy, carboalkoxy, amido or dialkylamido substituted lower (C.sub.1 -C.sub.4) alkyl or hydroxy substituted lower (C.sub.2 -C.sub.4) alkyl;
• or (3) compounds of the formula:
• ##STR11## wherein R.sup.4 and R.sup.5 are, individually, hydrogen, lower (C.sub.1 -C.sub.4) alkyl, or cycloalkyl having 5 or 6 carbon atoms in the ring;
• n is an integer from 1 to 4, inclusive, and x is 1 or 2.