Process for producing microcellular shaped pieces of dimensional accuracy, particularly shoe soles

Abstract

Abstract The invention relates to a process for the manufacture of microcellular shaped pieces, particularly shoe soles, in several vulcanization stages. In the first step, there is compounded a stock containing an elastomer, a plastomer and/or a thermoplastic elastomer, a blowing agent, an accelerator system and usual compounding ingredients used commonly in the rubber industry, e.g. plasticizers and fillers. This stock is prevulcanized and partially cross-linked in a closed mould under pressure at a temperature and for a time determined by the accelerator system, and the prevulcanized stock is expanded. In a further vulcanization phase, this prevulcanized, expanded semiproduct is completely vulcanized in a closed mould, and finally, the completly vulcanized product is cooled under pressure in a closed mould thereby hardening the component and stabilizing the final product in its predetermined form. By the aid of the invention, it has become possible to eliminate the phenomenon of postexpansion and postshrinkage, respectively, in the case of vulcanized, microcellular product, as a result of which in the second vulcanization stage there are produced shaped pieces of high dimensional accuracy and of a low apparent density (0.2 to 0.7 g/cc) having uniformly distributed cells, and the strength properties of which comply with every practical requirement.

Inventors

• 👤 Boris Nisonovich Dinzburg
• 👤 Jury Alexandrovich Smetkin
• 👤 Vladimir Iosifovich Alexenko
• 👤 Vsevolod Andreevich Mikhailov
• 👤 Dr Ivan Lorant
• 👤 Gyozo Seltenreich
• 👤 Jeno Keszei
• 👤 Gyorgy Marton
• 👤 Albert Balazsfai
• 👤 Jeno Donath
• 👤 Erno Bolcskei

Bibliographic Details