Testing adhesion of cord or wire in rubber

摘要

A novel method and mold apparatus for testing adhesion of cord or wire in rubber which measures "intrinsic" adhesion, i.e. adhesive strength independently of the tearing strength and stiffness of the rubber matrix. Each test specimen is formed of two uncured preformed or premolded blocks, called coupons, in respective preform molds. Two wire segments are inserted coaxially between the coupons in preformed grooves and the assembly is molded and cured. The proximate ends of the segments are buried in or embedded within the body of the specimen, but spaced apart along the axis of the wire segments and the body of the test specimen. The specimen is stressed only by the wire segments. In an Instron or like test machine, the free ends of the wire segments are pulled at a selected rate to failure. Failure of the adhesion is observed to start at the embedded end of the wire segment and progress outwardly along the segment which is pulled from the body or matrix. The force required is recorded and the maximum observed force, together with the otherwise determined rubber stiffness, provides a measure of the intrinsic face-to-face adhesion of the particular wire to the particular rubber. A preferred mold apparatus provides mold plates useful both in preforming the coupons and in mold curing the specimens.