To provide a curable aqueous composition, a method for treating a heat-resistant fiber or a heat-resistant nonwoven fabric from the fiber with the composition, and a product prepared thereby.

This curable aqueous composition comprises (a) a polyacid comprising at least two carboxylic acid groups, acid anhydride groups or salts thereof, (b) a polyol comprising at least two hydroxy groups, and (c) an emulsion polymer comprising, for a copolymer unit, more than 30 wt.%, on the basis of the weight of solids of the emulsion polymer, of an ethylenically unsaturated acrylic monomer comprising a≥5C alkyl group, wherein the ratio of the equivalent number of the carboxylic acid groups, acid anhydride groups or salts to the equivalent number of the hydroxy group is 1/0.01-1/3, and less than 35% of the carboxylic acid groups, acid anhydride groups or salts is neutralized by a nonvolatile base.