PURPOSE: To reduce the amt. of an org. solvent used therein and obtain a water- resistant cross-linked coating film by compounding a specific carboxyalkylcellulose nitrate with a cross-linker in a specified wt. ratio.

CONSTITUTION: The compsn. comprises 60.0-99.9wt.% carboxyalkylcellulose nitrate having a degree of nitration per anhydrous glucose unit of 0.2 or greater and a degree of carboxyalkyl-etherification per anhydrous glucose unit of 0.05 or greater and 0.1-40.0wt.% cross-linker (e.g. a carboxyl- or hydroxyl-reactive compd. such as a melamine resin, or an organometallic chelating compd. contg. Zn, Al, etc.). The compsn. is prepd. by adding a specified amt. of water, if necessary together with a specified amt. of a water-sol. solvent (e.g. an alcohol), to the nitrate in a hermetically sealed reactor equipped with a stirrer, stirring them to provide a homogeneous mixture, and dissolving the cross-linker in the mixture. A coating film formed from the compsn. is dried at 20-40°C.