Lion Copolymer Holdings LLC, a synthetic rubber maker with a plant in Geismar, will purchase Ashland Inc.’s elastomers business based in Port Neches, Texas.

Financial terms were not disclosed by the companies Thursday.

The transaction is expected to be completed by Dec. 31 and is contingent on certain regulatory approvals and standard closing conditions.

The elastomers business accounted for about 17 percent of Ashland Performance Materials’ $1.6 billion in sales for a 12-month period ending June 30. The business primarily serves

the North American replacement tire market. It was acquired by Ashland as part of its International Specialty Products transaction in August 2011.

The Port Neches plant employs 250 people.

“With the acquisition of the Ashland elastomers business, we are pleased once again to be in this segment of the synthetic rubber business,” said Jesse Zeringue, executive vice president of Lion Copolymer Holdings. “We think the size of the facility in Port Neches,

access to feedstock and excellent storage capacity, combined with specialty products such as hot styrene-butadiene rubber polymers and high styrene polymers, provide us with an excellent growth opportunity.”

Separately, Lion Copolymer’s ethylene propylene diene monomer (EPDM) products are used in automotive weather seals and hoses, industrial and consumer hoses, weather seals, molded goods, wire and cable insulations, windows, roof sheeting, thermoplastic

elastomers, conveyor belts, seals, footwear, printing rolls and viscosity modifiers for lubricants.