Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Process of treating scrap or waste product containing solid...
Patent
1998-03-12
1999-04-06
Nutter, Nathan M.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Process of treating scrap or waste product containing solid...
521 44, 521 445, 521 495, C08J 1104
Patent
active
058919260
ABSTRACT:
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.degree. C. under a pressure of at least about 3.4.times.10.sup.6 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.degree. 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.degree. C. to about 300.degree. C. under a pressure of at least about 3.4.times.10.sup.6 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.
REFERENCES:
patent: 4104205 (1978-08-01), Novotny et al.
patent: 5284625 (1994-02-01), Isayev et al.
patent: 5602186 (1997-02-01), Myers et al.
Hunt Lawrence Keith
Kovalak Ronald Roy
Nutter Nathan M.
Rockhill Alvin T.
The Goodyear Tire & Rubber Company
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