Key Facts
• On September 10, 2025, Mitsui Chemicals, Idemitsu Kosan, and Sumitomo Chemical announced a merger.
• The merger will integrate their domestic general-purpose resin businesses by April 2026.
• The petrochemical industry faces challenges from China’s overproduction and declining domestic demand.
• The merger focuses on the polyolefin resin business.
• Sumitomo Chemical will transfer its domestic operations to Prime Polymer and join as a shareholder.
• Prime Polymer, co-owned by Mitsui Chemicals and Idemitsu Kosan, operates in the Keiyo region.
• Mitsui Chemicals will hold a 52% stake, Idemitsu Kosan 28%, and Sumitomo Chemical 20% post-merger.
• The merger aims to cut annual costs by over 8 billion yen through facility consolidation.
• Combined revenue is projected to reach approximately 390 billion yen.
• Mitsui Chemicals’ CEO emphasized strengthening the business foundation through collaboration and restructuring.
Summary
Mitsui Chemicals, Idemitsu Kosan, and Sumitomo Chemical have agreed to merge their domestic general-purpose resin businesses, targeting completion by April 2026. This strategic move addresses challenges in the petrochemical industry, including China’s overproduction and shrinking domestic demand. The merger will consolidate the polyolefin resin operations, with Sumitomo Chemical transferring its domestic business to Prime Polymer, a joint venture of Mitsui Chemicals and Idemitsu Kosan. Post-merger, Mitsui Chemicals will hold a 52% stake, Idemitsu Kosan 28%, and Sumitomo Chemical 20%. The integration aims to reduce annual costs by over 8 billion yen and achieve a combined revenue of approximately 390 billion yen. Mitsui Chemicals’ CEO highlighted the importance of collaboration and restructuring to strengthen the business foundation.
