3ply Medical Disposable Mask Our History Qingdao Zhuo An Engineering Technology Co., Ltd. is a large combined enterprise specializing in petrochemical technology R & D, producing, sales and trade. Our Factory We mainly takes C5 and C9 fractions as raw materials, adopting international advanced technology and producing techniques, and has been long-term committed to the R & D and production of petroleum resin. Our Product The main products include: C5 petroleum resin, C9 petroleum resin, C5/C9 Copolymerized Petroleum resin, hydrogenated C5 petroleum resin, http://www.zhuoan-pr.com/