To provide a method for preparing an aqueous solution of regenerated cellulose at a low cost with low risk of gelling and metal contamination, and to manufacture a separator for a nonaqueous battery using the aqueous solution of the regenerated cellulose prepared by the preparation method.
A method for preparing an aqueous solution of regenerated cellulose comprises: pretreating regenerated cellulose by immersing the same in a sodium hydroxide solution of prescribed concentration at a prescribed temperature for at least 1 h; and subsequently immersing the regenerated cellulose in 5.0-6.0 wt.% sodium hydroxide solution, provided that the prescribed temperature and the prescribed concentration fall within the shaded area in a phase diagram shown in Fig.2. A separator for a nonaqueous secondary battery is manufactured by immersing the aqueous solution of the regenerated cellulose in a microporous sheet composed of an inorganic material and forming a network structure of cellulose therein.
KUGA SHIGENORI
UNIV TOKYO
Shinichi Abe
Yuji Tsujida