EVALUATION OF THE ADHESION BETWEEN NYLON 6,6 CORD AND CHLOROPRENE RUBBER

Nylon 6,6 cord is used as reinforcement in rubber products (e.g., tires, hoses, and belts). The problem of bonding rubber to textile cords is due to the big difference between the surface properties. To obtain a durable reinforced rubber product, it is necessary to produce a bond strong enough to resist the different conditions, for example, high temperature, cyclic tension, compression loads, and shock, depending on the applied rubber product. Choosing a suitable adhesive system and addition of an adhesion promoter into the rubber compound are factors which play a very important role. Many other factors are known to affect the bond strength obtained with resorcinol formaldehyde latex (RFL) adhesives. For example, method of RFL preparation, its composition, amount of adhesive applied to cords, its distribution on the cord, heat treatment conditions after dipping, method of storing dipped cord, composition of rubber compound, and vulcanization conditions are factors affecting the cord-to-rubber bonding. The scope of this research is to study the effect of the heat treatment conditions (temperature and time) after dipping and the effect of the presence of an adhesion promoter in the rubber compound on the adhesion between nylon 6,6 cord and chloroprene rubber. On studying the static adhesion (H-pull-out test) for this system, the test results showed that RFL dipping solution increases adhesion by about a factor of 2, while the heat treatment conditions have only a moderate effect. The resorcinol/hexamethylene tetramine based adhesion promoting material in the rubber compound gave a significant improvement, with both undipped and dipped cords.