Method for preparing nanodispersions of fluorinated phthalocyanine pigments

1. A method for preparing a nanodispersion comprising the steps of:

(i) introducing into a milling apparatus a solid fluorinated phthalocyanine pigment according to Formula (I):

wherein:

M is a metal cation chosen from Groups 1b, 2b, 2a or 3a of the Periodic Table of the Elements;

R is fluorine, a perfluoroalkyl or a perfluoroaryl group;

z is 1 to 4;

L is an anionic ligand; and

n is 0 or 1 such that overall charge on molecular unit is neutral; and

(ii) milling with agitation the solid fluorinated phthalocyanine in an organic solvent into a suspension of particles so that at least 80 volume % of the particles have a particle size of less than 100 nm.

2. The method of claim 1 , where the fluorinated phthalocyanine is according to Formula (II):

wherein R is fluoro or trifluoromethyl and z is 1-4.

3. The method of claim 2 , wherein R is fluoro and z is 1.

4. The method of claim 1 , where the fluorinated phthalocyanine is according to Formula (III):

wherein:

R is fluoro or trifluoromethyl;

z is 1-4; and

X is a halide, hydroxide, —O—, —O—Si(R) 2 —O—Si(R) 2 —O—, or —O—Si(R) 2 —R—Si(R) 2 —O— where R is independently alkyl or aryl.

5. The method of claim 4 , wherein R is fluoro, z is 1 and X is —O—Si(R) 2 —O—Si(R) 2 —O— where R is independently alkyl or aryl.

6. The method of claim 1 , wherein the milling step includes a solid milling media which can be separated from the nanodispersion.

7. The method of claim 6 , wherein the milling media is a polymeric resin or a ceramic particle.

8. The method of claim 1 , wherein at least 75 volume % of the particles have a particle size of less than 30 nm.

9. The method of claim 1 , wherein at least 70 volume % of the particles have a particle size of less than 22 nm.

10. The method of claim 1 , wherein at least 65 volume % of the particles have a particle size of less than 18 nm.

11. The method of claim 1 , wherein the organic solvent has a gamma c hydrogen bonding parameter of at least 8.0.

12. The method of claim 11 , wherein the organic solvent is selected from ketones, amides, alcohols, polyols, ethers and esters.

13. The method of claim 12 , wherein the milling step includes a dispersion agent selected from sulfates, sulfonates, acrylic and styrene-acrylic copolymers, sulfonated polyesters and styrenics, phosphorated polyesters and dispersion agents that contain amine, acidic or polyether functional groups.

14. The method of claim 1 , wherein the milling step includes another solid pigment provided that the fluorinated metal phthalocycanine comprises at least 50 weight percent of the mixture.