AQUEOUS RESIN COMPOSITION COMPRISING BLOCK-ISOCYANATE-CONTAINING AQUEOUS EMULSION COMPOSITION AS CURING AGENT, AND COMPOSITION FOR AQUEOUS BAKING COATING OR ADHESIVE AGENT WHICH UTILIZES THE SAME

摘要

Disclosed is a one-pack type aqueous resin composition containing a block isocyanate compound, which comprises the main component (I) and a curing agent (II) mentioned below. The aqueous resin composition is improved in dispersibility in water and storage stability, and can produce a coating film exhibiting various improved coating film properties at a temperature around the dissociation temperature of the block component and having improved weather resistance. The main component (I): an acrylic resin. The curing agent (II): an aqueous emulsion composition containing a block isocyanate, which is produced by the following steps: reacting an organic polyisocyanate (a1) with a high-molecular-weight polyol having a nonionic polar group (a2), and blocking the isocyanate group with a blocking agent (C), thereby producing a block polyisocyanate component (A); reacting an organic polyisocyanate (b1) with a high-molecular-weight polyol (b2) and a carboxyl-containing anionic low-molecular-weight glycol (b3) in the reaction system to produce a carboxyl-containing, isocyanate-terminated urethane prepolymer (B); neutralizing the carboxyl group in the reaction system with a neutralizing agent (D); emulsifying the reaction mixture in water; and carrying out the chain extension reaction with a chain-extending agent (E) to produce a highly crosslinked polyurethane resin.