To obtain a resin composition based on a vinyl acetate/acrylic resin copolymer resin emulsion, being of a one-package type, stable, and of a non- formaldehyde type, and having excellent water resistance by emulsion- polymerizing a monomer mixture comprising vinyl acetate and acrylic acid in a specified ratio in the presence of a polyvinyl alcohol resin containing a specified amount of diacetone groups as side chains.

The polyvinyl alcohol resin contains 0.1-20.0 mol% diacetone groups as side chains and is obtained by saponifying a copolymer of a diacetone- group-containing monomer (e.g. diacetoneacrylamide) with a vinyl ester (e.g. vinyl acetate). The saponification is desirably accomplished by an alkali lysis comprising using an alkali hydroxide in methanol. It is desirable that the resin has a number-average degree of polymerization of 300-3,000 and a degree of saponification of at least 85 mol%. The monomer mixture comprises 80.0-99.9 wt.% vinyl acetate and 0.1-20.0 wt.% acrylic acid.