RIKEN TECHNOS Conducts Joint Study with Tohoku University on a Recycling Method for PVC Coating Material Used in Automotive Wire Harnesses

RIKEN TECHNOS CORPORATION (Head Office: Chiyoda-ku, Tokyo; Representative Director, President & CEO: Kazuaki Tokiwa) is conducting joint research with Tohoku University on a technology for recycling coating material for wire harnesses, one of RIKEN TECHNOS’s products made from polyvinyl chloride (PVC).

The recycling of wire harnesses recovered from scrapped vehicles is primarily done using the nugget method, in which specific gravity sorting is performed on finely ground scrap to separate it into copper and coating material. The recovered copper can be reused, but because some copper powder gets mixed in with the various resin coating materials, such as PVC, it is difficult to recycle the coating material.

Our attention was drawn to a technology—developed by a group including Professor Yoshioka and Associate Professor Kumagai from the Graduate School of Environmental Studies, Tohoku University—that uses advanced wet separation on wire harnesses to separately recover both high grade copper and PVC coating material. We are now conducting joint research on reusing PVC coating material.
This advanced wet separation technology immerses wire harnesses in organic solvent, which causes the PVC coating material to swell. A ball mill is then used to apply an appropriate impact force, which makes it possible to separate and recover the copper wire and the PVC coating material. Compared to the conventional nugget method, this new technique offers a higher level of separation performance, so it can be used to recover high purity PVC coating material, so it is poised to enable the reuse of this material in various PVC products.

We have investigated blending the PVC coating material recovered using this technology with virgin PVC, plasticizer, stabilizer, and other additives to re-compound it. In our laboratory investigations, we have confirmed that by optimizing the formulation and kneading conditions, it is possible to produce material with mechanical properties equivalent to conventional products even when the percentage of recycled material is raised as high as 40%.

We will continue to work together with Tohoku University to further expand the range of applications of products recycled through re-compounding and to optimize separation methods and formulations for individual applications.

The results of this joint research are scheduled to be presented at the Automotive Engineering Exposition 2026 YOKOHAMA, which will held at Pacifico Yokohama from May 27 to 29, 2026.

RIKEN TECHNOS will contribute to the realization of a sustainable society by discovering new possibilities for the effective use of PVC and other plastics.

Yoshioka Laboratory, Tohoku University
https://www.che.tohoku.ac.jp/~env/index-e.html

Automotive Engineering Exposition 2026 YOKOHAMA
https://aee.expo-info.jsae.or.jp/en/yokohama/