Aqueous dispersion of polyester resin, production method of the same, and aqueous coating composition

摘要

The present invention is to provide an aqueous dispersion of a polyester resin with an excellent molecular weight stability, its production method, and an aqueous coating composition. An aqueous dispersion of a polyester resin having an acid value of 8 to 40 mg KOH/g and a weight average molecular weight of 9,000 or more contains an organic solvent in an amount of less than 0.5% by mass. A method for producing the aqueous dispersion of a polyester resin comprising a step of at first obtaining an aqueous dispersion of polyester resin containing not less than 0.5% by mass of an organic solvent by adding the polyester resin and a basic compound to an aqueous medium to make the resulting mixture aqueous and a step of removing the organic solvent from the aqueous dispersion. An aqueous coating composition can be obtained by adding a curing agent to the foregoing aqueous dispersion of a polyester resin.