Paint composition for vehicle intermediate coating with improved chipping resistance

1 . A paint composition comprising:

a polyester resin;

a melamine resin;

a color pigment;

an extender pigment;

3 wt % to 4 wt % of cellulose nanofibers (CNFs), based on a total weight of the paint composition;

0.5 wt % to 1 wt % of a dispersant, based on the total weight of the paint composition;

a surface conditioner;

an antisagging agent; and

a solvent.

2 . The paint composition of claim 1 , wherein, based on the total weight of the paint composition, the paint composition comprises:

15 wt % to 20 wt % of the polyester resin;

7 wt % to 13 wt % of the melamine resin;

15.1 wt % to 20.3 wt % of the color pigment;

8 wt % to 15 wt % of the extender pigment;

0.5 wt % to 1.5 wt % of the surface conditioner;

4 wt % to 6 wt % of the antisagging agent; and

30 wt % to 43 wt % of the solvent.

3 . The paint composition of claim 1 , wherein the color pigment comprises titanium dioxide (TiO 2 ) and carbon black,

wherein, based on the total weight of the paint composition, the paint composition comprises:

15 wt % to 20 wt % of the titanium dioxide (TiO 2 ); and

0.1 wt % to 0.3 wt % of the carbon black.

4 . The paint composition of claim 1 , wherein the extender pigment comprises calcium carbonate (CaCO 3 ).

5 . The paint composition of claim 1 , wherein the cellulose nanofibers (CNFs) have a width of 10 to 100 nm, and a length of 1 to 5 μm.

6 . The paint composition of claim 1 , wherein the dispersant comprises a silicone-free polyester polymer.

7 . The paint composition of claim 1 , wherein the surface conditioner comprises a silicone-modified acrylic resin.

8 . The paint composition of claim 1 , wherein the antisagging agent comprises at least one selected from the group consisting of acrylic derivatives and modified urethane.

9 . The paint composition of claim 1 , wherein the solvent comprises distilled water, an alcohol-based solvent, and a glycol-based solvent,

wherein, based on the total weight of the paint composition, the paint composition comprises:

25 wt % to 35 wt % of the distilled water;

4 wt % to 6 wt % a content of the alcohol-based solvent; and

1 wt % to 2 wt % a content of the glycol-based solvent.

10 . A paint film manufactured using the paint composition of claim 1 , wherein the paint film has a chipping resistance evaluation grade of Grade 2 or less as evaluated at an air pressure of 5 kgf/cm 2 and a temperature of −20° C. using as a gravelometer.