There is a case where a coating having water- and oil-repelling property, stain resistance and non-tackifying property is required to prevent contamination of surfaces of electric devices for home use, office apparatuses, automobiles, building products and the like. In order to impart these surface properties, a polymer having a perfluoroalkyl group is applied to paints. For example, there are reported a method wherein a polymer having a perfluoroalkyl group is admixed with paints for general use (JP-A-96659/1983) and a method wherein a paint comprises a polymer having a perfluoroalkyl group as a main component (JP-B-32872/1989), but the stain resistance thereof is not enough.
JP-A-175386/1992 discloses a water- and oil-repelling paint composition prepared by adding a water- and oil-repelling agent containing a fluoroacrylic resin to a film forming resin comprising a urethane resin component and a silicone resin component, but there is no description as regards stain resistance. The paint composition of that invention has a disadvantage that because a large amount of the water- and oil-repelling agent is added, so-called the cissing is easy to occur at the time of coating and thus uniform coating is difficult to obtain. Generally, if a water- and oil-repelling agent comprising, as a main component, a polymer having a perfluoroalkyl group is mixed in a paint, cissing is easy to occur at the time of coating due to poor compatibility of the water- and oil-repelling agent with the paint, and a uniform coating is difficult to obtain. Also, in case of a coating having an acrylic resin or a polyester resin as a main component and being crosslinked with a melamine resin or an isocyanate type curing agent, it is known that when a crosslinking density is raised to increase hardness of the coating, stain resistance is enhanced, but water- and oil-repelling property is not good.
In JP-B-21686/1985, a paint composition comprising solvent soluble fluorine-containing copolymers having hydroxyl group is disclosed. However, these solvent soluble fluorine-containing copolymers having hydroxyl group are poor in oil-repelling property and stain resistance because of a low fluorine atom content. Also, JP-A-199211/1988 proposes a paint composition comprising a solvent soluble fluorine-containing copolymer having curable moieties and a perfluoroalkyl containing alcohol or a fluorosilicone compound. Though there is oil-repelling property on the surface of the coating, in a stain resistance test using a red ink, which is referred to hereinafter, there occurs a problem that after drying of the red ink, there remains marks of an oil droplet which cannot be wiped off completely.
An object of the present invention is to provide a paint composition being capable of forming a coating being excellent in both water- and oil-repelling property and stain resistance, and to provide a painted article.