Paint composition which has excellent staining resistance and paint films obtained by coating same

1. A paint composition comprising:

a hydroxyl group-containing resin (A);

a crosslinking agent (B), which reacts with hydroxyl groups;

a radical copolymer (C); and

an organosilica sol (D);

wherein the radical copolymer (C) has,

(a) a monomer composition, with respect to the total mass of radically polymerizable monomer, of from 70.0 to 99.8 mass % unsaturated carboxylic acid amide, from 0.2 to 10 mass % radically polymerizable organosiloxane and from 0 to 29.8 mass % other radically polymerizable monomer,

(b) a weight average molecular weight from 1,500 to 15,000, and

(c) a hydroxyl group value of from 10 to 50 mg KOH/g,

wherein the organosilica sol (D) is of average particle diameter from 1 to 30 nm,

and wherein the solid fraction mass ratio represented by

{( C )component+( D )component}/{( A )component+( B )component}

is from 3 to 30%, and the solid fraction mass ratio represented by

{( C )component/( D )component}

is from 0.2 to 5.0.

2. The paint composition of claim 1 , wherein the hydroxyl group-containing resin (A) has a weight average molecular weight of from 2,000 to 60,000 and a hydroxyl group value of from 10 to 200 mg KOH/g.

3. The paint composition of claim 1 , wherein the hydroxyl group-containing resin (A) is a hydroxyl group-containing polyester resin.

4. The paint composition of claim 1 , wherein the crosslinking agent (B) is selected from melamine resins and blocked polyisocyanate compounds.

5. The paint composition of claim 1 , wherein the solid fraction mass ratio represented by

{( A )component/( B )component}

is from 1 to 9.

6. A paint film, comprising a substrate coated with the paint composition of claim 1 .