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Located in Baton Rouge, Louisiana, the plant can also make nitrile butadiene rubber (NBR), said Balmoral Advisors.
The sale was approved in US District Court, Middle Louisiana District.
Balmoral did not disclose the price of the sale. However, court documents said the sales price was $5.6m.
Had Lion failed to close on the sale, East West would have sold the plant to Galata Copolymers, which placed a $5.52m bid for the plant.
At the time of the filing, the company estimated its real property was worth $10.20m and its personal property was worth $6.43m. Meanwhile, total liabilities totalled $49.88m.
East West had bought the plant from Lion Copolymer earlier this decade. East West itself was formed by a former CEO of Lion, Greg Nelson.