Market and product

Compiled by Bao Hien

Most tire recycling efforts to date have stopped at recovering a single material — most commonly recovered carbon black (rCB) for reuse in new tire production, or recycled steel for concrete reinforcement. A four-company alliance in Europe has just announced a more ambitious approach: building a fully closed loop that turns scrap tires back into basic chemical feedstock, which is then resynthesized into rubber for new tire manufacturing.

Step one: pyrolysis splits scrap tires into two material streams

The starting point of this circular chain is pyrolysis — breaking down end-of-life tires at high temperature in an oxygen-free environment. This process splits scrap tires into two main products: solid recovered carbon black (rCB) and liquid tire pyrolysis oil (TPO).

This isn't an entirely new technology — pyrolysis has been used for years by some recycled-carbon-black producers to supply rCB as a partial substitute for virgin carbon black (which is petroleum-derived) in tire rubber formulations. What sets this new model apart is that the second output stream — pyrolysis oil — is no longer treated merely as a byproduct, but becomes the feedstock for the next step in the chain.

Step two: converting pyrolysis oil into chemical monomers

Tire pyrolysis oil is fed into a chemical production complex, where it is co-processed with conventional petrochemical feedstock on the same existing production line to produce basic chemical monomers — specifically butadiene and styrene, the two main feedstock components for synthesizing the artificial rubber used in tire manufacturing.

Because the pyrolysis oil is blended with petrochemical feedstock within the same production line rather than run through a separate, physically isolated stream, the recycled-origin share of the monomer output is determined using a "mass balance" method — an accounting approach that allocates the recycled feedstock fed into the system to a corresponding share of the output, rather than requiring complete physical separation of the two feedstock streams. This method is certified under ISCC PLUS, an international certification standard widely used in the chemical and plastics industry to trace recycled or bio-based feedstock content when a mass-balance accounting approach is applied.

Step three: synthesizing rubber and closing the loop

The resulting monomers are then used to synthesize artificial rubber certified under the same ISCC PLUS standard. This rubber, together with the recovered carbon black from the initial pyrolysis step, is fed back into new tire production lines — completing a loop that runs from scrap tires, through pyrolysis, through chemical synthesis, and back into new tires, all while still meeting the same quality and performance standards as tires made from virgin feedstock.

Why a multi-party chain instead of one company going it alone

A notable aspect of this collaborative model is that the circular chain requires expertise across several distinct fields — pyrolysis technology, petrochemical processing and monomer production, rubber synthesis, and tire manufacturing — capabilities that few, if any, single companies hold in-house all at once. This is why the model was built around linking several specialized companies, each handling one stage of the process, rather than a single company investing in the entire value chain on its own — reflecting a broader pattern in heavy-industry circular economy efforts: genuine circularity is difficult to achieve through the action of any one company alone, and instead requires a coordinated industrial ecosystem with clearly certified traceability among all parties involved.

Limitations worth noting

The model has not yet published specific targets for production volume or the share of recycled feedstock in overall tire output, nor a timeline for scaling up commercially. In addition, because it relies on mass-balance accounting rather than complete physical separation, the actual recycled-material content in any given batch of monomer or rubber product is difficult to verify through direct analysis alone — a limitation common to mass-balance approaches broadly used across the recycled-chemicals industry, not unique to this particular model. Even so, building a genuinely closed supply chain — rather than simply recycling a single material in isolation — is still seen as a notable step forward compared with the more fragmented tire-recycling models that came before it.