A process of reclaiming rubber.

摘要

Chemical direct reclaiming of rubber by mixing pui- verulent scrap rubber having a particle size of at most 1 mm. preferably at most 0.4 mm. with a reducing agent, an oxidizable iron metal chloride and at least one plasticizer. The mixture is agitated for a short time, at most.30 min. and normally at most 15 min., in the solid phase in air at a temperature of not more than 100°C, usually approximately room temperature, in a powder mixer for direct degradation of double bonds in the rubber. The reducing agent is from 0.2 to 1 weight %, preferably from 0.2 to 0.8 weight % of phenyl hydrazine or from 0.2 to 0.8 weight % of diphenyl guanidine. The iron metal chloride is admixed in an amount of from 0.1 to 0.4 weight % and is preferably ferrous chloride. The plasticizer shall comprise at least one member from the group tall oil pitch and dipentene, and this plasticizer may optionally be used in mixture with some other plasticizer, such as mineral process oil. The total amount of plasticizer is at most 17.5 weight %. The amount of a plasticizer other than tall oil pitch and dipentene is at most 10 weight %. The amount of dipentene is at most 5 weight % and is from 0.5 to 5 weight % if the dipentene is used as the only plasticizer or is used in mixture with another plasticizer. The amount of tall oil pitch is at most 17.5 weight % and is from 7 to 17.5 weight % if the tall oil pitch is used as the only plasticizer or is used in mixture with a plasticizer other than dipentene. If tall oil pitch is used in mixture with dipentene. the amount of tall oil pitch varies in inverse proportion to the amount of dipentene and is from 8 to 16 weight % with dipentene amounts of from 5 to 0,5 weight %. All of the percentages are calculated on the mixture of pulverulent rubber scrap, reducing agent, iron metal chloride and plasticizer.

Without preceding refining, the reclaimed pulverulent rubber with a low admixture percentage (for example about 6%) of raw rubber (natural rubber or styrene butadiene rubber) can be used directly for the manufacture of vulcanized rubber products.