In October 2000, seeking to develop promising areas of business such as battery separators and air filters, the company acquired stock (33.3% of issued shares) in NIPPON MUKI CO., LTD., owned by Hitachi Chemical Company, Ltd. In April 2001, this company became a wholly owned subsidiary when NSG acquired the remaining stock via an exchange of shares. This enabled the company to develop both these businesses to become either the only or the leading such businesses in Japan. The battery separator business was then absorbed into the main company, which also acquired the Tarui Factory (now the Tarui Plant).