Hyundai Chemical's mixed-xylene plant starts operations Hyundai Oilbank said Tuesday that its Hyundai Chemical plant, a newly built joint-venture with Lotte Chemical, has begun to produce mixed-xylene (MX),. MX is a mixture of benzene, toluene and xylene and is used to produce polyester, PET and gasoline additives. The plant in Seosan, South Chungcheong Province, will