Taiyo Oil and Mitsui Chemicals collaborate to expand chemically recycled products, leveraging mass balance methods and pyrolysis oil for circular economy.
Taiyo Oil Co., Ltd. and Mitsui Chemicals, Inc. have begun a joint study with the shared goal of accelerating the transition toward a circular economy. This collaboration aims to expand the production and supply of chemically recycled products, building on each company’s individual initiatives in chemical recycling and bio-based materials.
Taiyo Oil has made significant progress in recent years. In June 2025, its Shikoku Operations site in Imabari, Ehime, earned ISCC PLUS certification, followed by its headquarters in July 2025. These certifications demonstrate compliance with global sustainability standards and mark important milestones in advancing chemical recycling projects. To further strengthen its capacity, the company is constructing new facilities to process pyrolysis oil derived from waste plastics and other feedstocks. This oil will serve as a key raw material for chemical recycling, making use of the company’s refinery infrastructure.
Meanwhile, Mitsui Chemicals has been steadily integrating sustainable raw materials into its production system. Since December 2021, the company has introduced bio-based hydrocarbons into its cracker at the Osaka Works in Takaishi, Osaka. Using the mass balance approach, Mitsui Chemicals has been producing and marketing plastics and chemicals with reduced environmental impact. Building on this foundation, the company began in March 2024 to use pyrolysis oil from waste plastics, sourced from CFP CORPORATION, to manufacture and market chemically recycled products under the same mass balance framework.
The collaborative study between Taiyo Oil and Mitsui Chemicals represents the next phase of development. Under this arrangement, Taiyo Oil’s Shikoku Operations will process the heavy fractions of pyrolysis oil, a material that is difficult for Mitsui Chemicals’ crackers to handle effectively. From this process, chemically recycled naphtha, propylene, and other mass balance-certified products will be supplied to Mitsui Chemicals. The companies also plan to explore methods to diversify the types of waste plastic feedstocks that can be utilized and expand their portfolio of bio-based products.
Both organizations believe this partnership has the potential to support not only a more sustainable society but also a regenerative one, where resources are continuously cycled back into production.
At the core of these initiatives lies the mass balance method, which plays a critical role in advancing chemical recycling and the use of bio-based resources. The Ministry of the Environment in Japan defines this method as one where different raw materials—such as bio-based and fossil-based—are mixed during production and distribution. Properties of the sustainable raw materials are then allocated proportionally to the final products, based on input quantities. Importantly, the end products are indistinguishable in quality from conventional fossil-derived plastics and chemicals.
This approach is vital because it enables the introduction of biomass in applications where direct use has historically been challenging. It also opens the door to scaling up chemical recycling solutions, supporting broader adoption of circular economy practices, and moving society closer to carbon neutrality.
Taiyo Oil, through this initiative, aims to enhance its supply of bio-based and chemically recycled chemical products. Together with Mitsui Chemicals, the company seeks to establish new pathways for sustainable production and resource utilization that can serve as a model for the wider industry.
