Adhesion of Steel Tire Cord to Rubber Compounds Mutual Influence of Brass and Rubber Compounds on the Adhesion

A study was made on strands to define the evolution of the original adhesion as well as thermic aging adhesion both under and free from moisture conditions. The following parameters have been recorded: composition of brass, brass thickness and the formulations of calendered rubber compounds that are representative of the compounds found in tire manufacturing. The resulting graphic curves show a displacement of maximal adhesion depending essentially on the copper content, on the adhesion promoters used in rubber compounds (cobalt salt or resorcinol-silica-hexamethylene tetramine system), and on the sulfur content with as much regard to the original adhesion as to the aging adhesion. The influence of the brass plating thickness agrees with the results of a study made on the diffusion of sulfur in brass by the means of X-ray photoelectron spectroscopy [XPS or electron spectroscopy for chemical analysis (ESCA)].