Resin composition for coating materials

Provided is a resin composition for coating materials, which has high refractive index and high transparency without requiring the use of a solvent. The present invention provides (1) a resin composition for coating materials, which is characterized by containing a specific dinaphthothiophene compound that has one or more polymerizable functional groups having an ethylenically unsaturated double bond (component (A)), a monofunctional (meth)acrylate that contains one or more aromatic rings (component (B)), and a radical photopolymerization initiator (component (C)), and which is also characterized in that the content ratio of the component (A) is within the range of 15-60 parts by mass and the content ratio of the component (B) is within the range of 40-85 parts by mass.