BATON ROUGE, La. (AP) -- Specialty chemical manufacturer Albemarle Corp. said late Tuesday it will significantly increase the price of a key plastic additive.

The price of its Ethanox 330 polymer antioxidant, a petroleum derivative, will rise by up to 50 percent effective on orders shipped after Sept. 15 or as contracts and sales agreements allow.

John McChesney, global business manager-additives, said Albemarle has experienced "unprecedented increases" in raw materials, waste handling and disposal costs.

Albemarle is a manufacturer of chemicals for consumer electronics, petroleum and petrochemical processing, transportation and construction and packaging materials. Albemarle's polymer antioxidants and polymer additive blend packages help maintain the performance integrity and processing stability of plastics, adhesives and other materials.

Shares of Albemarle traded at $40.26, down 32 cents, in Wednesday morning trading.