PROCESS FOR MAKING AN ANTI-SOILING COATING COMPOSITION AND A COATING MADE THEREFROM

1 . A process to provide a substrate having improved anti-soiling properties comprising the steps

a) Providing a substrate having a surface;

b) Providing a coating composition comprising:

i. organic-inorganic core shell nanoparticles having a core comprising an emulsion stabilizer C and a shell comprising inorganic oxide; and

ii. at least one water soluble solvent;

iii. at least 5 wt % water based on the total weight of the coating composition; and

iv. an organic compound A;

c) Applying a layer of the composition to the surface to obtain a coated substrate; and

d) Drying the applied layer to obtain a coated substrate.

2 . The process according to claim 1 , wherein in step d) the applied layer is exposed to a temperature of at least 5 degrees Celsius, for the duration of at least at least one hour.

3 . The process according to claim 1 , wherein the composition comprises a binder, preferably the binder comprises an inorganic oxide binder, preferably the inorganic oxide binder comprises inorganic oxide precursor is selected from metal alkoxides, metal chelates, metal salts, and mixtures thereof, preferably the inorganic oxide binder comprises an alkoxy silane.

4 . The process according to claim 1 , wherein the composition comprises between 0 to 30 wt-%, preferably between 0.1 to 30 wt-%, pref between 1 and 15 aluminium oxide equivalents of aluminium containing compound, preferably the coating formulation comprises between 0.5 to 30 wt-% aluminium oxide equivalents of aluminium containing compound.

5 . Process according to claim 1 , wherein the organic-inorganic core shell nanoparticles have particle size is in a range of from 20 to 300 nm as measured using DLS.

6 . The process according to claim 1 , wherein compound A is a non-polymeric compound.

7 . The process according to claim 1 , wherein compound A has a boiling point of at least 10° C. and at most 300° C., preferably compound A has a boiling point of at least 30° C. and at most 200° C.

8 . The process according to claim 1 , wherein compound A has solubility in water at room temperature of at most 3 kg/m 3 .

9 . Process according to claim 1 , wherein copolymer C is obtained form

1-25 mole % of at least one cationic or basic monomer M1, like vinyl monomers with a tertiary amine group;

50-99 mole % of at least one non-ionic apolar monomer M2; and

0-25 mole % of at least one polar, anionic or acidic monomer M3; with the sum of M1, M2, and M3 adding up to 100%.

10 . Process according to claim 1 wherein mass ratio C/A is 0.15-1.0.

11 . Process according to claim 1 wherein metals include at least one element selected from Si, Al, Be, Bi, B, Fe, Mg, Na, K, In, Ge, Hf, La and lanthanoids, Sb, Sn, Ti, Ta, Nb, Y, Zn and Zr.

12 . A coated substrate obtained with the process according to claim 1 .

13 . Use of the coating composition as defined in claim 1 to improve anti-soiling properties of a substrate

14 . An anti-soiling coating composition comprising

i. organic-inorganic core shell nanoparticles having a core comprising and an emulsion stabilizer C and a shell comprising inorganic oxide;

ii. at least 5 wt % water based on the total weight of the coating composition;

iii. at least one water soluble solvent; and

iv. an organic compound A.

15 . Process of making an anti-soiling coating composition comprising the steps of

1) Preparing an oil-in-water emulsion by mixing

an apolar organic compound A;

a cationic addition copolymer C as emulsion stabilizer; and

aqueous medium of pH 2-6;

at a mass ratio C/A of 0.1 to 2, to result in 1-50 mass % (based on emulsion) of emulsified droplets of particle size 30-300 nm;

2) Providing an inorganic oxide shell layer to the emulsified droplets by adding to the emulsion obtained in step 1) at least one inorganic oxide precursor, to result in organic/inorganic core-shell nano-particles with mass ratio core/shell of from 0.2 to 25;

3) Optionally combining the core-shell nanoparticles thus obtained with water and/or water soluble solvent;

4) Optionally adjusting pH; and

5) Optionally adding an organic or inorganic polymeric or polymerizable binder.