IMPROVEMENTS IN AND RELATING TO THE RECYCLING OF ELASTOMERIC MATERIALS

摘要

A PROCESS OF RECYCLING USED SULPHUR-CURED ELASTOMERIC MATERIALS COMPRISING MASTICATING THE SAID ELASTOMERIC MATERIALS AT TEMPERATURES BELOW 50°C WITH A NOVEL CHEMICAL MIXTURE WHICH IS CAPABLE OF INITIATING PROTON EXCHANGE IN A CONTROLLED MANNER AND THEREBY OPEN UP OR DELINK THE VULCANISED NETWORK OF THE ELASTOMERIC MATERIALS. THE NOVEL CHEMICAL MIXTURE IS MADE FROM ONE OR MORE COMPOUNDS WHICH ARE CAPABLE OF PERFORMING RUBBER ACCELERATOR FUNCTION AND ONE OR MORE ACTIVATORS CAPABLE OF INITIATING PROTON EXCHANGE AT TEMPERATURES BELOW 70°C AND THEREBY OPEN UP OR DELINK THE VULCANISED NETWORK OF THE SULPHUR-CURED ELASTOMERIC MATERIAL TO PROVIDE SULPHUR-CURABLE RECLAIMED ELASTOMERIC MATERIAL.THE PREFERRED MIXTURE COMPRISES ZINC SALT OF DIMETHYDITHIOCARBAMATE AND MERCAPTOBENZOTHIAZOLE IN THE MOLAR RATIO IN THE RANGE OF 1:1 TO 1:12, PREFERABLY DISPERSED IN DIOLS, AND ACTIVATED IN THE PRESENCE OF STEARIC ACID, ZINC OXIDE AND SULPHUR. THIS MIXTURE WHEN BLENDED WITH VULCANISED ELASTOMERIC CRUMBS IN CONCENTRATIONS OF 6 PARTS BINDER PER 100 PARTS OF RUBBER CRUMBS ON A MILL EFFECTIVELY DELINKS THE VULCANISED NETWORK AND RENDERS THE COMPOUND READY FOR MOULDING AND VULCANIZATION. THE OBTAINED RECYCLED RUBBER COMPOUNDS DISPLAY SATISFACTORY LEVEL OF PHYSICAL AND DYNAMIC CHARACTERISTICS.SUCH COMPOUNDS CAN BE DIRECTLY USED IN MOULDED GOODS OR IN ADMIXTURE WITH FRESH COMPOUNDS IN TYRES AND RELATED AREAS.