# Mitsui Chemicals, Idemitsu Kosan, Sumitomo Chemical to integrate PP and LLDPE into Prime Polymer

Mitsui Chemicals, Idemitsu Kosan, and Sumitomo Chemical signed an MOU to integrate Sumitomo Chemical's polypropylene and linear low-density polyethylene businesses in Japan into Prime Polymer, a joint venture of Mitsui and Idemitsu, aiming to strengthen domestic polyolefin competitiveness.

- Type: Acquisition
- Announced: 2025-09-10
- Where: Japan, Japan
- Status: announced
- Capacity: 1.59 million tons/year of polypropylene and 0.72 million tons/year of polyethylene
- Products: polypropylene, linear low-density polyethylene
- Sectors: [Plastics and Polymers](https://endata.com/sectors/plastics-polymers.md)

## Companies

- [Mitsui Chemicals](https://endata.com/companies/19809.md)
- [Idemitsu Kosan](https://endata.com/companies/19808.md) (acquirer)
- [Idemitsu Kosan](https://endata.com/companies/19808.md) (partner)
- [Mitsui Chemicals](https://endata.com/companies/19809.md) (acquirer)
- [Mitsui Chemicals](https://endata.com/companies/19809.md) (partner)
- [Sumitomo Chemical](https://endata.com/companies/20503.md) (partner)
- [Sumitomo Chemical](https://endata.com/companies/20503.md) (target)
- [Prime Polymer](https://endata.com/companies/31997.md) (acquirer)
- [Prime Polymer](https://endata.com/companies/31997.md) (target)

## Sources

- [sumitomo-chem.co.jp](https://www.sumitomo-chem.co.jp/english/news/detail/20250910e.html), 2025-09-10: "Mitsui, Idemitsu and Sumitomo Chemical have explored the opportunities for collaboration to strengthen the competitiveness of the domestic PO business, including PP and polyethylene (PE), and have reached a mutual understanding as set forth in the MOU."
- [sumitomo-chem.co.jp](https://www.sumitomo-chem.co.jp/news/detail/20250910.html), 2025-09-10: "本事業統合により、三井、出光、住友の3社協力のもと80億円/年以上の合理化を目標として生産体制等を最適化し、強靭でエッセンシャルな企業体としての競争力を一層強化します。"
- [mltanalytics.com](https://www.mltanalytics.com/post/prime-polymer-sumitomo-chemical-to-combine-polyolefin-businesses), 2025-09-10: "Prime Polymer, a joint venture of Mitsui Chemicals and Idemitsu, operates the PO business of these partners."
- [chemweek.com](https://chemweek.com/document/show/phoenix/6078333), 2025-09-10: "Prime Polymer JV to absorb Sumitomo Chemical’s Japanese PP, LLDPE businesses"
- [ptonline.com](https://www.ptonline.com/news/merger-consolidates-polyolefin-supply-in-japan), 2025-09-11: "The integration is expected to increase production capacity to 1.59 million tons/yr of polypropylene and 0.72 million ton/yr of polyethylene."
- [diamond.jp](https://diamond.jp/articles/-/372898), 2025-09-17: "（石油化学事業の）再編・統合に向けた一つのステップ。これから幾つものプロジェクト、ステップを踏んで強化していく。"
- [commoplast.com](https://commoplast.com/news/details/17625/English/), 2025-10-07: "The move seeks to strengthen cost competitiveness, enhance technological collaboration, and reinforce Japan's position in an increasingly constrained polyolefin market."

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Data from Endata (https://endata.com/). Announcements are summarized from public sources and may be incomplete; check the linked originals.