Announcement of Pilot Facility Operation for Superabsorbent Polymer Recycling Technology

Sumitomo Seika Chemicals Co., Ltd. (Headquarters: Chuo-ku, Osaka; President: Yoshiake Oda) announces the completion and commencement of operations at a pilot facility within its Himeji Plant (Himeji City, Hyogo Prefecture) for chemical recycling technology of superabsorbent polymers (hereinafter "SAP") contained in used disposable diapers (hereinafter "this technology"), as publicly announced on October 17, 2024.

In Japan, diaper consumption is increasing due to the aging population, and the proportion of used disposable diapers in general waste is projected to reach approximately 7% by fiscal year 2030※1. Currently, most used diapers are incinerated; however, material-specific recycling is being promoted to reduce incineration volumes and advance resource circulation. Nevertheless, "horizontal recycling"—reusing SAP separated from used diapers back into new diapers—has not yet been realized, prompting our company to develop this technology.

The newly operational pilot facility aims to establish an industrial-scale manufacturing process using this technology. Specifically, we will evaluate the quality and safety of regenerated SAP, establish the recycling process, and verify CO₂ emission reduction effects, with completion targeted by fiscal year 2026※2.

Additionally, as a third-party assessment of the environmental impact of this technology, Waseda University's Dr. Norihiro Itohira Laboratory (Department of Environmental Resources Engineering, School of Creative Science and Engineering, Faculty of Science and Engineering) will conduct a Life Cycle Assessment (LCA) based on data collected from this pilot facility.

Our company aims to socially implement this technology by fiscal year 2030. Alongside establishing an industrial manufacturing process through the pilot facility, we will collaborate with partner companies responsible for material separation and local governments to build a comprehensive recycling system for used disposable diapers.

※1 Refer to the Ministry of the Environment's website (Diaper Recycling | Environmental Restoration and Resource Circulation | Ministry of the Environment (env.go.jp)).

※2 This demonstration project has been selected for the Ministry of the Environment's "Fiscal Year 2024 Subsidy for Measures to Reduce Carbon Dioxide Emissions – Promotion of Decarbonized Circular Economy Systems (including Demonstration Projects for Establishing Resource Circulation Systems for Plastics, etc.)".

Pilot Facility Exterior Pilot Facility ①

Pilot Facility ② Pilot Facility ③

<Reference> Illustration of Sumitomo Seika's Chemical Recycling Technology for SAP (Steps ②–④ below)

② Technology to chemically decompose only the cross-linking points of SAP separated from used disposable diapers

Hydrolysis breaks the ester bonds (cross-links) in SAP, converting it back to polyacrylic acid, an intermediate.

③ Technology to "separate and purify" decomposed SAP from other impurities

The decomposed SAP is dissolved in water and purified, with only polyacrylic acid precipitated as a solid.

④ Technology to chemically recombine only the cross-linking points of purified polyacrylic acid

The precipitated polyacrylic acid is re-cross-linked to regenerate SAP.

Experiments conducted by our company have confirmed that the performance of this regenerated SAP—such as water retention and absorbency under pressure—is equivalent to that of the SAP for diapers currently manufactured and sold by our company.

<Press Inquiry Contact>

Sustainability Promotion Office (Public Relations) Email: info_corporate-communications@sumitomoseika.co.jp