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.
