A New Tire Cord Adhesion Test

Abstract

Abstract A new tire cord adhesion test is reported. Although developed primarily for measuring adhesion of rubber to tire cord, the test is applicable to any cord- or wire-reinforced composite, for example, rubber hose or belting. The specimen is a rubber bar of square cross section containing two partially embedded cord ends opposite each other. Upon the application of sufficient tensile force to the cords, failure is initiated at the tip of the embedded end and proceeds along the cord to the exterior, resulting in pull-out of one of the ends. This result contrasts with the initiation of failure in a specimen of the pull-through type containing a throughgoing cord. In the latter specimen, failure initiates where the cord emerges from the rubber and runs back into the interior. Failure is adhesive when pull-out occurs. Under special conditions cohesive failure (tear) occurs and the specimen is cleaved transversely. Reproducibility is excellent and the test has high discriminating power. A theoretical equation permits calculation of the energy of adhesion.