The recycling of waste rubber is an important issue when it comes to use resources efficiently. Most rubber producers recycle already at least small amounts of their rubber waste, e.g., by adding ground rubber waste to fresh compounds. However, this way is restricted to very small amounts and does not solve the problem of disposing many thousand tons of rubber waste, particularly from tires (GTR = Ground Tire Rubber). The recycling of GTR is an important approach towards resource efficiency by making a putative waste a valuable raw material.
For reprocessing GTR a material is necessary to bind the ground rubber. Such a binder should have the following properties:
- act as crosslinking Agent
- coating of the rubber granules
- improve processing
- Easy to handle
- Non toxic
Processing with VESTENAMER®
The material meeting these requirements is VESTENAMER® trans-polyoctenamer (TOR). Due to its melting range at 54°C, it functions as a plasticizer at processing temperatures. This property enables a very good coating of the ground rubber and a reduction of compound viscosity. Subsequent vulcanization converts VESTENAMER® into a true elastomer.
Compounds based on ground rubber and VESTENAMER® can be prepared in the traditional way by mixing in an internal mixer, when available. For a much easier reprocessing GTR is coated with TOR, oil and curing additives in a simple powder blender, similar to the mixing technology of thermoplastics.