CALCULATION OF TIMES AND TEMPERATURES FOR PRESS VULCANIZATION OF THICK RUBBER PADS

Abstract

ABSTRACT Rubber manufacturers need simple rules to enable them to find the correct cure time and temperature for thick articles. To this end finite element analysis, controlled by Python scripting, has been used to calculate press times that meet specifications for adequate cure for uniaxial heat flow through molded rubber pads over a range of thicknesses. Three press temperatures, the effect of first preheating the rubber, and the rate of cooling were investigated. A low press temperature, preheating of the rubber, and fast cooling were required to achieve a reasonably even state of cure through thick moldings. The heat of vulcanization was included in some of the models. Its effect was small. Unified plots of the simulation results for five commercial rubber compounds are presented, and simple equations are provided to enable the cure time at any cure temperature to be estimated. The applicability of the results to fast cures of thin sections is discussed.