E4S Awards - Evonik

Essen, Germany-based Evonik AG has developed a process that enables the use of up to four times more recycled rubber in new tires than is possible with existing methods.

The level of rubber recyclate incorporated into tires has been very limited up to now as the polymer structure hampers interaction with other materials, according to Evonik.

In particular, it said, the sulphur bonds create a highly robust, three-dimensional network, which conventionally has an upper limit of about 5% when it comes to introducing ground tire rubber from end-of-life-tires into new tires.

Using a special formulation containing vinyl silanes, Evonik says it can now reverse the vulcanisation “more effectively than previously possible” –  cleaving the sulphur bridges in the rubber, while leaving “as many of the long carbon chains as possible untouched.”

In trials, recyclate levels in the rubber blend could be increased to up to 20%, said Evonik, which is now set to start next-stage testing and trials – towards seeing customers use the system in commercial-scale industrial production.

Judging comments

Impressive that the technology can deliver a four-fold increase the effectiveness of conventional devulcanization processes and raise the proportion of recyclate in rubber blends up to 20%. As Evonik states: “Rubber is far too valuable a raw material to be used only once in tires. We want to incorporate it into a circular system.”

Scores very highly in terms of potential for upcycling: allowing four-fold increase in the level or rubber recyclate that can be incorporate into compounds.

As a major player in the field of rubber chemicals, Evonik is well equipped to deliver on the significant potential offered by this technology.