Photocatalyst-containing water-based curable coating compositions and process for production thereof

The present invention provides a photocatalyst-containing water-based curable coating composition capable of forming a cured coating film having an excellent durability against the oxidative decomposition effect caused by the photocatalyst, and an excellent crack resistance, as well as excellent weather resistance and stain resistance; and a method for producing the coating composition. Specifically, the present invention provides a photocatalyst-containing water-based curable coating composition comprising: one of a water-based dispersion (X1) or a water-based dispersion (X2), which includes a water-based medium, a polymer segment (A) having a neutralized acid group, a polysiloxane segment (B) forming a composite resin (AB) by chemically bonding with the polymer segment (A), a polysiloxane segment (C) derived from an alkyltrialkoxysilane condensate (c) with an alkyl group of 1 to 3 carbon atoms, the polysiloxane segment (C) forming a composite resin (ABC) by coupling with the polymer segment (A) and the polysiloxane segment (B) via silicon-oxygen bonds, and fine particles of a photocatalytic oxide (D), wherein the water-based dispersion (X1) is formed by dispersing or dissolving the composite resin (ABC) and dispersing the fine particles of a photocatalytic oxide (D) in the water-based medium, the water-based dispersion (X2) is formed by dispersing resin particles in a water-based medium, the resin particles formed by the encapsulation of the fine particles of a photocatalytic oxide (D) within the composite resin (ABC); and a curing agent (E) for curing the composite resin (ABC), and a method for producing the coating composition.