Brabender extruder helps to recycle rubber waste
A research project of the Osnabrück University of Applied Sciences with industrial partners aims to develop a new one-step recycling process.
EPDM rubber is one of the most commonly used rubbers for synthetic elastomers, which are used in the production of car tires, among other applications. Its use in the manufacturing of car tires, for example, produces vulcanized production waste that is difficult or impossible to reuse - often in large quantities compared with the total amount of raw materials used.
Common recycling methods are problematic
For the recovery of rubber waste, a common way of recycling is to grind it to a high degree of fineness and to return rubber powder serving as a filler to the production cycle in combination with new raw material. Problem: The higher the proportion of rubber meal from rubber waste in the injection moulding process, the more the meal has a qualitative effect on the material properties.
Another possibility to devulcanize rubber waste requires the absolute purity of the rubber for reuse in production. This requires the separation of production waste according to type, which can only be achieved by 10% of the companies in the German rubber industry, partly due to the high operating costs of the cleaning and sorting plants.
Osnabrück University of Applied Sciences conducts research on alternative methods
This dilemma is to be remedied by a project funded by the Deutsche Bundesstiftung Umwelt (German Environmental Foundation) to develop a solvent-free activation process for ground EPDM rubber. This was developed by the University of Osnabrück together with the company M.D.S. Meyer. The result: Rubber products containing 25-50 percent of activated EPDM particles and liquid polymers, developed in a continuous extrusion process, as well as a positive ecological balance with lower CO2 emissions, landfill and disposal costs.
This method is the basis of the follow-up project, also backed by the DBU, for the "Development of a continuous one-step extrusion process for devulcanization of rubber waste and its universal reuse in products at the property level of new elastomer". The Faculty MKT (Management Culture and Technology) at the campus of the University of Applied Sciences Osnabrück in Lingen is working on this project. The aim is to combine the three process steps devulcanization, activation and continuous mixing into one process step using a Brabender TSE 20/40 twin-screw extruder.
The new process to be developed should enable small and medium-sized manufacturers of EPDM rubber to independently recycle their production waste into a secondary raw material that can be used up to 100 percent in a processing procedure for new products.