| 摘要 |
535,531. Devulcanizing rubber. SOC. ITALIANA PIRELLI. April 6, 1940, No. 6266. Convention date, April 27, 1939. [Class 70] Vulcanized rubber is de-vulcanized by subjecting it in divided condition to the action of a rubber solvent or swelling agent at atmospheric temperature or not above 50‹C. for sufficient time to obtain a swelling only of the rubber, then heating the swollen rubber in the presence of a de-vulcanizing agent under superatmospheric pressure. The de-vulcanizing agent is removed and the solvent washed out preferably after drying the rubber. Solvents or swelling agents include middle and heavy mineral oils, high boiling point aliphatic hydrocarbons, wood tar and wood tar oils, coal tar and coal tar oils, resin oil and hydrogenated naphthalene. The solvent may be removed by aliphatic alcohols, alkylacetates and acetone. The devulcanizing agent may be water, or a solution of caustic alkali, alkali sulphide, sulphite or hyposulphite. An example is given using naphtha as solvent. |
