Houston-based Kraton Corp.’s stockholders approved its proposed $2.5 billion in cash acquisition by South Korea-based DL Chemical Co. Ltd., Kraton announced on Dec. 9. Kraton produces styrenic block copolymers and pine chemicals, including some used in production of lubricants.  Sea-Land Chemical Co., which distributes specialty additives for the lubricants industry and household, industrial and institutional cleaning markets, promoted Taryn Osborn to customer service manager.