Abstract: A coating agent includes a film-forming component including a component A consisting of a urethane (meth)acrylate having an isocyanuric ring skeleton, a component B consisting of a tri(meth)acrylate having an isocyanuric ring skeleton and having no urethane bond, and a component C consisting of colloidal silica having a (meth)acryloyl group and a hydrocarbon group having 3 to 13 carbon atoms; and a component D consisting of a photoradical polymerization initiator. The content of the component D is 0.1 parts by mass or more and 10 parts by mass or less based on 100 parts by mass of a total of the film-forming component.

Abstract: A coating agent includes a film-forming component containing a component A consisting of a urethane (meth)acrylate having an isocyanuric ring skeleton, a component B consisting of a tri(meth)acrylate having an isocyanuric ring skeleton and having no urethane bond, a component C consisting of a multi-functional (meth)acrylate having a (meth)acrylic equivalent of 80 to 200, and a component D consisting of a urethane (meth)acrylate that has a polycarbonate skeleton, two to four polymerizable unsaturated groups per molecule, and a weight average molecular weight of 10,000 or less, and a component E consisting of a photoradical polymerization initiator. The content of the component E is 0.1 parts by mass or more and 10 parts by mass or less based on 100 parts by mass of the total film-forming component.

Abstract: A coating agent has: a film-forming component containing an organosilicon compound having a radical polymerizable functional group and an alkoxysilyl group; and a film-curing component composed so that a base and a radical can be generated on irradiation with ultraviolet light. The film-curing component includes a nonionic photobase generator having no ionic bond in the molecular structure. The content of the nonionic photobase generator is 0.1 parts by mass or more and 50 parts by mass or less, based on 100 parts by mass of the organosilicon compound.

Abstract: A coating agent includes: a film forming component including a component A consisting of a urethane (meth)acrylate having an isocyanuric ring skeleton, a component B consisting of a tri(meth)acrylate having an isocyanuric ring skeleton and having no urethane bond, a component C consisting of a polymerizable urethane which has a polycarbonate skeleton derived from a polycarbonate diol having an alicyclic structure, 3 or more polymerizable unsaturated groups per molecule, a weight average molecular weight of 10,000 to 40,000, and a content ratio of the alicyclic structure of 10 mass% to 25 mass%, and a component D consisting of colloidal silica having a (meth)acryloyl group; and a component E consisting of a photoradical polymerization initiator. The content of the component E is 0.1 to 10 parts by mass based on 100 parts by mass of the total film forming component.