Optimization of Adhesion in Textile Cord–Rubber Composites: An Experimental and Predictive Modeling Approach

The adhesion between rubber compounds and textile cords plays a critical role in determining the overall performance and durability of rubber-based composites, particularly in tire applications. Despite extensive research on adhesion mechanisms, optimizing adhesion through systematic modeling remains challenging due to the complex interactions between rubber formulations, textile treatment, and processing conditions. This study presents an integrated experimental and predictive modeling approach to investigate and optimize the adhesion performance of nylon 6.6 textile cords in rubber compounds. Initially, the effects of different accelerator types-including diphenyl guanidine (DPG), 2,2'-Dithiobis(benzothiazole) (MBTS), N-tert-butyl-2-benzothiazole sulfenamide (TBBS), and N-cyclohexyl-2-benzothiazole sulfenamide (CBS)-on adhesion properties were systematically evaluated. Key parameters such as cure characteristics, Mooney viscosity, and mechanical properties of the rubber compounds were analyzed using a moving die rheometer (MDR), Mooney viscometer, and tensometer. To enhance adhesion performance, a statistical optimization approach based on the Box-Behnken design was employed, focusing on the influence of accelerator, curing agent, and resin contents. The results indicate that an optimized rubber formulation comprising 1.6 phr curing agent, 0.3 phr resin (HMMM), and 0.5 phr accelerator (MBTS) yields the highest adhesion strength. This study provides the first systematic modeling of adhesion between nylon 6.6 textile cords and rubber compounds using response surface methodology (RSM), offering valuable insights into the material design for improved interfacial bonding in tire manufacturing.