COMPOUNDING FOR ADHESION TO BRASS-COATED STEEL WIRE.

A number of the most influential factors in compounding, processing, curing and service of rubber for adhesion to brassed steel cord have been identified. Curing systems have been shown to have the greatest influence on adhesion and coverage. Adhesion can be reduced if the compound is subjected to significant processing prior to cure and this effect can be minimized by use of a prevulcanization inhibitor. Bond strength is also reduced by overcure and when cure temperature exceeds 150C in the absence of pressure at the interface. Partial replacement of sulphur by the sulphur donor dimorpholinodisulfide increases the retention of adhesion on aging as does the inclusion of certain efficient antidegradants. Consistently higher adhesion values are obtained both before and after aging when the SRH (silica-resorcinol-hexamethylenetetramine) bonding system in included in formulations.