Patent ID: 6346207
Filing Date: 2002-02-12
Classification: B29C

Abstract:
A process for preparing EVA foam, comprising the steps of:kneading a mixture of an EVA resin, a foaming agent, a cross-linking agent, a lubricant, and a filler to form a kneaded composition; preparing a mold that has upper and lower mold halves which confine a mold cavity therebetween; placing an amount of the kneaded composition in the mold such that the volume ratio of the kneaded composition to the mold cavity is about 0.15 to 0.5 and such that the kneaded composition is laid on the lower mold half; heating the upper and lower mold halves in a manner that the temperatures of the upper and lower mold halves are not less than a reaction temperature, at which foaming and curing of the kneaded composition take place, so as to conduct a first stage of foaming and curing of the kneaded composition and so as to permit the kneaded composition to expand in the mold cavity from the lower mold half toward the upper mold half; and raising the temperature of the upper mold half to be higher than that of the lower mold half when the kneaded composition expands to a volume such that the volume ratio of the kneaded composition to the mold cavity is about 0.9 to 0.95 so as to conduct a second stage of foaming and curing of the kneaded composition.