Sumitomo Riko Co. Ltd. (TYO:5191) held a ceremony in Thailand to mark the opening of SumiRiko Chemical and Plastic Products (Thailand) Ltd. (SRK-CP). A subsidiary of Sumitomo Riko in Rayong Province, SRK-CP manufactures and sells precision parts for office equipment. Tetsu Matsui, Sumitomo Riko president and COO, said at the ceremony, which took place in early November, that he hopes…