A resin composition of the present invention is obtainable by adding a photo-polymerization
initiator (d) to a resin solution (a) containing a modified product of a thermoplastic
resin (A). The modified product is prepared by conducting radical polymerization
of the thermoplastic resin (A) with a (co)polymer (B) of a copolymerizable monomer
(C) comprising a monomer having an ,-mono-ethynically unsaturated
group, or the monomer and other copolymerizable monomers in a weight ratio (A)1(B)
of 1/9 to 9/1, in an organic solvent, or by conducting polymerization of a copolymerizable
monomer (C) comprising a monomer having an ,-mono-ethylenically unsaturated
group, or the monomer and other copolymerizable monomers in a weight ratio (A)/(C)
of 1/9 to 9/1, in an organic solvent in the presence of the thermoplastic resin
(A), and then conducting radical polymerization thereof. A paint including the
resin composition and a process for forming a coating film are also disclosed.
