Quality products from rubber residues

Rubber residues can be downcycled to floor coverings and safety crashpads, and for the first time, also processed into high-quality plastics. A new kind of material - the environmentally-friendly material mix is called EPMT - makes it possible.

Each year throughout the world, up to 22 million tons of rubber are processed and a large portion of it goes into the production of vehicle tires.

Once the products reach the end of their useful life, they typically land in the incinerator. In the best case, the waste rubber is recycled into secondary products. Ground to powder, the rubber residues can be found, for example, in the floor coverings used at sports arenas and playgrounds, and in doormats.

But until now, the appropriate  techniques for producing high-quality materials from these recyclables did not exist. Researchers at the Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT in Oberhausen, in Germany, recently succeeded in optimising the recycling of rubber waste materials. They have developed a material that can be processed into high-quality products, like wheel and splashguard covers, handles, knobs and steerable castors.

The new plastic compounds are called elastomer powder modified thermoplastics or EPMT for short. They comprise rubber residues crushed into elastomer powder that are blended with thermoplastics.

Dr. Holger Wack, scientist at UMSICHT, explains the production process, ''In the first step, the rubber residues, that can be metre-long rubber pieces, are granulated to three millimetre-large particles. The particles are cooled with liquid nitrogen and then ground into elastomeric powders. This is then conducted to the melt-mix process with thermoplastics and additives. Here we use, for example, polypropylene as a thermoplastic material.''