A process for reclaiming scrap vulcanized rubber

摘要

Natural or synthetic scrap vulcanized rubber, with or without a grinding agent, e.g. whiting, carbon black, is subjected, whilst under compression in a confined space, to a shearing action for 1-4 minutes, the average temperature of the scrap being maintained within the range 150 DEG -250 DEG F., avoiding peaks higher than 320 DEG F., and the portion of the powdered product passing a 20-mesh screen (U.S. Standard) is then subjected to further shearing action, at a temperature of from 300 DEG -400 DEG F., for a time sufficient to devulcanize the rubber which is then sheeted. The power input during the first grinding step is preferably 3-10 h.p. per pound of scrap and the process may be conveniently effected in a Banbury mixer provided with jacketed walls and hollow rotors through which cooling fluid, e.g. water at 34 DEG -40 DEG F. may be circulated.