Experimental and statistical studies of the effect of pressing time on the swelling and mechanical properties of the radial tyre tread compound

Abstract

Cars are the most important mode of transportation and play a significant role in the development of modern communities. Tyres, one of the main components of cars, hold strategic importance. Therefore, research aimed at improving the quality and increasing the production speed of tyres is an integral part of the strategic policy on this subject. In this study, the effects of pressing time in curing press (time of curing with pressure) on the structural properties of radial tyre tread were investigated. According to the one-factor response surface methodology, 10 samples that had different pressing times during their curing press were produced. The swelling test was used to study the cured compound structure. In this way, essential parameters such as diffusion coefficient and crosslinking density were calculated. The results showed that the vulcanised samples in free pressure conditions had the lowest amounts of crosslinking density. Also, these samples had the highest intrinsic diffusion coefficient. It is also observed that the intrinsic diffusion coefficient and crosslinking density have a relationship with pressing time. Mechanical tests were also performed to determine the dependence of the mechanical properties of the tyre tread on the duration of pressing time. As an obvious result, the cured samples in zero-pressure conditions had the lowest tensile strength, tear strength, hardness and the highest amount of resilience percentage. However, the abrasion parameter had the most negligible dependence on the pressing time. The results showed the dependence of the swelling and mechanical properties of the tread tyre compound on the pressing time. So, according to the optimal targeting for different variables and results, the optimal time of applying pressure during curing for the tyre tread compound has been obtained. As an important result, in the curing process, the pressurising can be stopped after about 14 min while the curing continues only with heat.