Water-soluble cellulose ether having improved filtering characteristics and selection method

摘要

A water-soluble cellulose ether is selected by judging whether the number of undissolved fibers having a size of 16-200 mum is up to 350 fibers/2 ml in a 0.1 wt % aqueous solution of the cellulose ether at 25° C. This water-soluble cellulose ether forms an aqueous solution which can be filtered without clogging and can form a very thin film without defectives.