Estimation of dynamic adhesion from static test results in the model cord–RFL–rubber system

Generally, nylon and polyester cords are used to reinforce rubber compounds. These composites are used in many sectors, such as tire and belt manufacturing. To increase adhesion performance a resorcinol–formaldehyde–latex (RFL) adhesive is applied on the cord, which bonds chemically to both cord and rubber and, thus, it improves both the thermodynamic work of adhesion and the loss function at the cord/rubber interface. Adhesion strength between the cord and rubber determines the performance of the system. So to study the performance of the cord–rubber system, adhesion strength must be evaluated. Cord–rubber adhesion strength can be evaluated in static and dynamic modes. The H-Pull (H-adhesion) test method is a static and relatively simple method that is usually employed to control raw material quality. Fatigue test is one of dynamic adhesion test methods that are used to determine the performance of cord–rubber interface. Some important factors such as cyclic stress and heat buildup are involved in this test procedure. To investigate the accuracy of the H-Pull test results, the cord–rubber samples were prepared using poly(ethylene terephthalate) (PET) cord and NR/SBR rubber. Then H-adhesion was determined at elevated temperatures. The adhesion strength was also evaluated in dynamic (fatigue) mode at different temperatures. Authors have proposed an equation to estimate dynamic adhesion from H-Pull test results.