Patent ID: 6133413
Filing Date: 2000-10-17
Classification: C08J,Y02W

Abstract:
A method of manufacturing devulcanized rubber comprising rubber with sulfur crosslinks thereof severed and carbon black particles of 100 nm or less in diameter comprising the steps of:(a) pulverizing vulcanized rubber selected from the group consisting of EPDM (ethylene-propylene-diene terpolymer) rubber, natural rubber, styrene-butadiene rubber and butyl rubber containing carbon black;(b) heating the pulverized vulcanized rubber containing carbon black in the temperature range of 280.degree. C. to 330.degree. C. when the rubber is EPDM rubber, 200.degree. C. to 270.degree. C. when the rubber is natural rubber, 200.degree. C. to 270.degree. C. when the rubber is styrene-butadiene rubber, or 180.degree. C. to 250.degree. C. when the rubber is butyl rubber;(c) applying a shearing pressure in the pressure range of 10 to 30 kg/cm.sup.2 when the rubber is EPDM rubber, 10 to 50 kg/cm.sup.2 when the rubber is natural rubber, 10 to 50 kg/cm.sup.2 when the rubber is styrene-butadiene rubber, or 10 to 30 kg/cm.sup.2 when the rubber is butyl rubber, while heating the pulverized vulcanized rubber containing carbon black, whereby sulfur crosslinking bonds in the vulcanized rubber are cut while main chains of the rubber are not cut, thereby preparing said devulcanized rubber.