METHOD OF PRODUCING AN ELASTOMER BLEND THAT IS SIMILAR TO THERMOPLASTIC ELASTOMERS, ON THE BASIS OF RECLAIMED RUBBER OR WASTE RUBBER

摘要

The invention relates to a method of producing an elastomer blend that is similar to thermoplastic elastomers on the basis of reclaimed rubber or waste rubber. According to this method, reclaimed rubber or waste rubber that has been reduced to powdered rubber is processed to compounds by subjecting it to a melt-mixing process in a mixer together with a thermoplastic material and at least one stabilizer in different weight percentages. The aim of the invention is to improve this method so that a mixture that consists of two phases that are usually incompatible, namely the powdered rubber and a thermoplastic material, is processed to a blend that is characterized by the properties of thermoplastic elastomers. Said blend should have a constant quality, should be reproducible and repeatedly recyclable and the method should allow the conversion in a melt-mixing process over a relatively short mixing period by choosing suitable materials for the thermoplastic constituent and other additives. To this end, at least one polypropylene copolymer or a mixture thereof with at least one polypropylene type is melted in the mixer and powdered rubber, at least part of which has been pre-swelled in a radical donor, is dosed to the melt. The powdered rubber is dispersed in the plastic matrix by applying high shearing strains and admixing radical-forming agents in order to couple the two phases that consist of the powdered rubber and the polypropylene copolymer or a mixture thereof in accordance with defined mixing parameters. The dynamic stabilization process is carried out at a temperature of the mixture that is above the melt temperature of the polypropylene copolymer or the mixture thereof but below the decomposition temperature of the powdered rubber and over a mixing period that allows the reaction of the radical former.