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 issimilar to thermoplastic elastomers on thebasis of reclaimed rubber or waste rubber. According to this method, reclaimedrubber or waste rubber that has been reduced topowdered rubber is processed to compounds by subjecting it to a melt-miningprocess in a mixer together with a thermoplasticmaterial and at least one stabilizer in different weight percentages. The aimof the invention is to improve this method so that a mixturethat consists of two phases that are usually incompatible, namely the powderedrubber and a thermoplastic material, is processedto a blend that is characterized by the properties of thermoplasticelastomers. Said blend should have a constant quality, shouldbe reproducible and repeatedly recyclable and the method should allow theconversion in a melt-mining process over a relativelyshort mixing period by choosing suitable materials for the thermoplasticconstituent and other additives. To this end, at least onepolypropylene copolymer or a mixture thereof with at least one polypropylenetype is melted in the mixer and powdered rubber, atleast part of which has been pre-swelled in a radical donor, is dosed to themelt. The powdered rubber is dispersed in the plasticmatrix by applying high shearing strains and admixing radical-forming agentsin order to couple the two phases that consist of thepowdered rubber and the polypropylene copolymer or a mixture thereof inaccordance with defined mixing parameters. The dynamicstabilization process is carried out at a temperature of the mixture that isabove the melt temperature of the polypropylene copolymeror the mixture thereof but below the decomposition temperature of the powderedrubber and over a mixing period that allows thereaction of the radical former.