Devulcanization of cured rubber

摘要

This invention is based upon the unexpected discovery that cured rubber can be devulcanized by heating it to a temperature of at least about 150 DEG C. under a pressure of at least about 3.4x106 Pascals in the presence of 2-butanol. The molecular weight of the rubber can be maintained at a relatively high level if the devulcanization is carried out in the presence of the 2-butanol at a temperature of no more than about 300 DEG C. This devulcanization technique does not significantly change the microstructure of the rubber and it can accordingly be used in the same types of applications as was the original rubber. In other words, the devulcanized rubber can be recompounded and recurred into useful articles in substantially the same way as was the original rubber. This invention more specifically discloses a process for devulcanizing cured rubber into devulcanized rubber that is capable of being recompounded and recurred into useful rubber products, said process comprising (1) heating the cured rubber to a temperature which is within the range of about 150 DEG C. to about 300 DEG C. under a pressure of at least about 3.4x106 Pascals in the presence of 2-butanol to devulcanize the cured rubber into the devulcanized rubber thereby producing a slurry of the devulcanized rubber in the 2-butanol; and (2) separating the devulcanized rubber from the 2-butanol.