Analysis of Temperature Distribution and Thermal Conductivity of Rubber Compound during Compression Molding Process

DOI: 10.14416/j.ind.tech.2023.05.001

Abstract

Uneven cure of thick-wall rubber products is regarded as one of the most undesirable phenomena since it results in a significant loss of mechanical properties. The primary objective of this study was to investigate the effect of the curing system, filler type, and content on the temperature distribution and thermal conductivity of rubber compounds during the compression molding process. A special compression mold was designed and constructed to measure the temperature distribution across the thickness of rubber parts. The measured results indicated that the efficient vulcanizing system (EV) gave a better temperature distribution across the thickness than conventional vulcanization (CV). Concerning the thermal conductivity of rubber compounds and vulcanizates, it was found that the thermal conductivity increased with the increase of filler content. In addition, the thermal conductivity of cured rubber dramatically decreased as compared to uncured rubber. Furthermore, it should be noted that the decreasing thermal conductivity of rubber compounds, especially for high carbon black loading and thick-wall moldings, directly affected the uneven cure of rubber products. In this work, the step cure was proposed to enhance the temperature distribution across the thickness of rubber compounds. The results obtained in this measurement showed that the step cure could improve the vulcanization efficiency as compared to the conventional method.