Mitsui, Idemitsu, and Sumitomo Restructure Polyolefins Business

On September 10, Mitsui Chemicals, Idemitsu Kosan, and Sumitomo Chemical announced a memorandum of understanding to integrate their polyolefins operations under Prime Polymer Co., Ltd. The plan envisions transferring Sumitomo’s polypropylene and LLDPE businesses into Prime Polymer and restructuring equity to Mitsui 52%, Idemitsu 28%, and Sumitomo 20%.

The integration, scheduled for April 2026, will create a company with 1.59 Mt/year PP and 0.72 Mt/year PE capacity, generating ¥387.3 billion in sales (approx. RMB 18.7 billion). The move is expected to achieve over ¥8 billion in annual cost synergies while addressing domestic overcapacity, declining demand due to demographics, and competition from imports.

Beyond cost optimization, the three companies will use Prime Polymer as a platform for green transformation, emphasizing bio-based feedstocks, chemical recycling, and low-carbon production technologies. The restructuring underscores Japan’s chemical sector strategy to consolidate and innovate for competitiveness in a shrinking domestic market.