Hagihara Industries Inc. (“Hagihara”), Kajima Corporation (President: Masafumi Kiryu; “Kajima”), and Takenaka Corporation (President: Masato Chono; “Takenaka”) have launched a demonstration project for the closed-loop recycling of flame-retardant sheets used at construction sites.

Closed-loop recycling is a form of material recycling in which used products are collected and processed into raw materials for manufacturing the same product again. Compared with methods such as thermal recycling, which involves incinerating waste plastics to recover energy, closed-loop recycling is a more advanced approach with a lower environmental impact due to reduced CO₂ emissions.

Under this project, flame-retardant sheets used at Kajima and Takenaka construction sites will be collected and recycled by Hagihara into new flame-retardant sheets. The recycled sheets will then be reused at Kajima and Takenaka construction sites, allowing the three companies to demonstrate the entire cycle of use, collection, reprocessing, and reuse.

The closed-loop recycling of flame-retardant sheets represents the first initiative of its kind in the construction industry and marks an important step toward realizing a circular economy. Through this project, the three companies aim to establish a new model for sustainable resource circulation at construction sites.

Background

The Act on Promotion of Resource Circulation for Plastics came into effect in April 2022, encouraging the promotion of material recycling, including closed-loop recycling, for products such as plastic sheets.

Used flame-retardant sheets, a type of plastic waste generated at construction sites, have long been considered difficult to recycle in a closed-loop system because of the flame-retardant agents they contain. However, Hagihara’s technological innovations have made it possible to overcome these technical challenges. At the same time, the practical implementation of closed-loop recycling requires not only technical feasibility but also a system capable of continuously collecting used sheets and supplying them to the recycling process in a stable manner.

Accordingly, the three companies have launched this demonstration project to verify not only the feasibility of recycling flame-retardant sheets but also the viability of the entire supply chain involved in the recycling process.

Overview of the Demonstration Project

In this project, the three companies will demonstrate a resource-circulation scheme across the entire supply chain, encompassing the use, collection, reprocessing, and reuse of flame-retardant sheets. The process is as follows:

Kajima and Takenaka will purchase flame-retardant sheets manufactured by Hagihara using recyclable materials and use them in actual construction projects. After use, the sheets will be sorted and collected at each construction site and transported to Hagihara’s recycling facilities. Hagihara will then reprocess the sheets into new products using proprietary technologies evolved from the specialized cleaning and pelletizing processes the company developed through its blue-tarp recycling operations. Kajima and Takenaka will purchase the recycled sheets and use them again at their construction sites. The three companies will continuously operate this resource-circulation scheme to verify its long-term feasibility.

Future Outlook

Leveraging the insights gained through this demonstration project, the three companies will continue advancing material recycling initiatives that address challenges facing the construction industry, thereby contributing to the realization of a circular economy.