Modified Curing System for Accelerated Sulfur Vulcanization of Rubber Article

Abstract

Sulphur vulcanization is the most widely used technique and it is an essential step in the manufacture of natural rubber-based products. Prolonged cure time of the rubber compounds wastes energy and affects the production rates. The effect is very significant in the manufacture of thick articles formed using different layers of rubber. A new vulcanizing procedure was tested in an attempt to shorten the optimum cure time of rubber compounds without affecting the performance of the product. In this new method, a latex master batch of curing ingredients except the curing agent (sulphur) was first prepared and was converted to the dry form by heating under controlled conditions. Calculated amounts of curing agents were incorporated into the dry master batch to form rubber compounds. Both the gum compound and the filled compound were prepared using the modified method as well as using the conventional compounding method for the purpose of comparison. Reduction in scorch time was observed for both the gum compound and the filled compound made by the modified method. The modified method reduced the optimum cure time by 33% and 19% for the gum compound and the filled compound respectively. It was found that the modified method could be used to cure rubber without significantly affecting the mechanical properties of the final product.