Technologies for Polymeric Cord / Rubber Adhesion in Tire Applications

A good adhesion between the rubber of a tire and the reinforcing polymeric cord is crucial for the overall tire performance and safety. Polymeric cords are commonly treated by a resorcinol-formaldehyde-latex (RFL) coating in order to obtain the desired adhesion. This is often done in combination with an epoxy coating in order to compatibilize the cord surface and the RFL coating.

An overview of these chemical treatments, which are dating back to the year 1938, is given, and recent developments in this field are shown. Economical and environmental disadvantages are the driving forces to find suitable replacements, and it is discussed, if one or both chemical treatments can be replaced and which technologies might be suitable.

Plasma treatment is one of the most promising candidates, in spite of the fact that it creates different surface and core properties. One major difference is the presence of the latex in the RFL coating, which provides a chemical link between the cord and the rubber matrix, thus the plasma treatment has to provide moeities which can couple the cord to the rubber. Another difference is the thermal impact of the plasma treatment, which influences the basic properties of the cord. Besides, the state-of-the-art is plasma treatment of single end cords, which has to be further developed for multiple cords.

In this overview, chemical and mechanical aspects as well as processing of treated polymeric cords will be discussed. New approaches in this research field are shown and compared.