Sumitomo Chemical and Trinseo Enter into Share Transfer Agreement Regarding Polycarbonate Joint Venture in Japan

Jan. 26, 2017

Sumitomo Chemical Co., Ltd. and Trinseo Holding B.V., a wholly owned subsidiary of Trinseo S.A. （NYSE：TSE）, have signed a definitive agreement for Trinseo to sell all of its 50 percent share in their Sumika Styron Polycarbonate （SSPC） joint venture to Sumitomo Chemical for an undisclosed price.

Sumika Styron Polycarbonate currently produces polycarbonate resins at production facilities in Niihama City, Ehime, Japan, and serves customers and markets throughout Asia. In addition to the sale of Trinseo’s ownership in the joint venture, the parties have agreed to continue long-term supply of polycarbonate resin to Trinseo’s Performance Plastics businesses and as such will maintain the strategic relationship between SSPC and Trinseo.

"Sumitomo Chemical is a natural owner for this Japan-based polycarbonate plant, and as an industry leader
in the region, Sumitomo Chemical is better positioned to manage and deliver value from this asset in the
future," said Tim Stedman, Senior Vice President and Business President for Basic Plastics and Feedstocks,
Trinseo. "At the same time, Asia Pacific continues to be an important growth region for Trinseo, and the
company is strongly committed to growing our Performance businesses in the region."

"We highly appreciate the long-term relationship with Trinseo and respect the decision by them. We will explore opportunities of further expanding polycarbonate business by leveraging technical capabilities we have developed long time, as Petrochemicals & Plastics Sector has a broad product portfolio," said Tomohisa Ohno, Director and Senior Managing Executive Officer of Sumitomo Chemical.

The transaction is expected to close on January 31, 2017. Terms of the agreement are not disclosed.

Following the close, it is expected that SSPC will operate as a wholly owned subsidiary of Sumitomo Chemical. SSPC will continue to operate and will be renamed Sumika Polycarbonate Limited after a transitional period.

SSPC was originally formed as Sumitomo Dow Limited in 1996 as a 50：50 joint venture between Sumitomo
Chemical Co., Ltd. and The Dow Chemical Company. After Styron （Trinseo） became an independent
company in 2010, it assumed Dow’s ownership share in the joint venture, which was renamed Sumika
Styron Polycarbonate （SSPC） at that time.

About Sumitomo Chemical

Headquartered in Tokyo, Japan, Sumitomo Chemical is one of Japan’s leading chemical companies, offering a diverse range of products globally in the fields of petrochemicals, energy and functional materials, IT-related chemicals and materials, health and crop science products, and pharmaceuticals. The company’s consolidated net sales for fiscal 2015 were approximately 2.1 trillion yen, and it has around 31,000 employees. For further information on Sumitomo Chemical, please visit the corporate website at http://www.sumitomo-chem.co.jp/english.

About Trinseo

Trinseo （NYSE： TSE） is a global materials solutions provider and manufacturer of plastics, latex binders, and synthetic rubber. We are focused on delivering innovative and sustainable solution to help our customers create products that touch lives every day — products that are intrinsic to how we live our lives — across a wide range of end-markets, including automotive, consumer electronics, appliances, medical devices, lighting, electrical, carpet, paper and board, building and construction, and tires. Trinseo had approximately $4.0 billion in revenue in 2015, with 15 manufacturing sites around the world, and more than 2,200 employees. For more information visit www.trinseo.com.

Forward Looking Statements

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