Composition and method for controlling the wettability of surfaces

1. A method for controlling the wettability of a substrate surface comprising:

a) coating the substrate surface with a coating formulation comprising a mixture of

i) at least one binder,

ii) hydrophilized hedgehog shaped particles pre-treated and coated with at least one hydrophilizing agent but not a hydrophobizing agent and hydrophobized hedgehog shaped particles pre-treated and coated with at least one hydrophobizing agent but not a hydrophilizing agent, and

iii) optionally at least one hydrophobizing agent or at least one hydrophilizing agent,

to form a coating layer; and

b) applying one or more post-layers of at least one hydrophobizing agent and/or at least one hydrophilizing agent on top of the coating layer,

wherein the at least one hydrophilizing agent is chosen independently in each instance of ii), iii), and b); and

wherein the at least one hydrophobizing agent is chosen independently in each instance of ii), iii), and b).

2. The method of claim 1 , wherein the substrate is selected from the group consisting of paper, board, wall-paper, wood, a wood composite, flake board, a plastic, foil, concrete, a coated rendering, an uncoated rendering, plaster, a metal, a ceramic, stone, a brickstone and glass.

3. The method according to claim 1 , wherein the coating formulation does not include the at least one hydrophobizing agent or the at least one hydrophilizing agent in iii).

4. The method according to claim 1 , wherein the coating formulation in iii) comprises the at least one hydrophobizing agent.

5. The method according to claim 1 , wherein the coating formulation in iii) comprises the at least one hydrophilizing agent.

6. The method according to claim 1 , wherein the at least one hydrophobizing agent is applied as the one or more post-layers in b).

7. The method according to claim 1 , wherein the at least one hydrophilizing agent is applied as the one or more post-layers in b).

8. The method according to claim 1 , wherein the coating formulation in iii) does not include the at least one hydrophobizing agent or the at least one hydrophilizing agent, and the at least one hydrophobizing agent is applied as the one or more post-layers in b).

9. The method according to claim 1 , wherein the hedgehog shaped particles are composed of aragonitic precipitated calcium carbonate in a form of clusters of needle like crystals.

10. The method according to claim 1 , wherein the hedgehog shaped particles are clusters and/or aggregates of scalenohedral precipitated calcium carbonate.

11. The method according to claim 1 , wherein the at least one binder is a styrene-acrylic latex, an acrylonitrile, a polyvinyl alcohol or linseed oil.

12. The method according to claim 1 , wherein the at least one hydrophobizing agent is chosen independently in each instance of ii), iii), and b) from the group consisting of fatty acids, stearic acid, palmitic acid, and their salts; alkylketene dimer;

polyacrylamide resins; silicone resins, polysiloxanes, polysiloxane modified with a functional silicone resin, and any mixture thereof.

13. The method according to claim 1 , wherein the at least one hydrophilizing agent is chosen independently in each instance of ii), iii), and b) from the group consisting of polyacrylic acids, salts of 1-hydroxyethane-1, 1-diphosphonic acid, alkali metal salts thereof, potassium salts thereof chelates of 1-hydroxyethane-1, 1-diphosphonic acid, aluminium hydroxide chelates thereof, aluminium hydroxide/1-hydroxyethane-1,1-diphosphonic acid chelates having a weight ratio of 1:5, and any mixture thereof.

14. The method according to claim 1 , wherein the at least one binder is present in the coating formulation in an amount of up to 250 wt % based on the weight of the hedgehog shaped particles.

15. The method according to claim 1 , wherein the at least one binder is present in the coating formulation in an amount of 3 to 25 wt %, based on the weight of the hedgehog shaped particles.

16. The method according to claim 1 , wherein the coating formulation further comprises one or more additives selected from the group consisting of dispersing agents, siliconizing agents, thickeners, rheology modifiers, anti-settling agents, defoamers, antioxidants, bluing agents, surfactants, crosslinkers, flame retardants, catalysts, pH buffers, fillers, dyes, pigments, optical brighteners, waxes, coalescence agents, and biocides.

17. The method according to claim 1 , wherein the coating formulation is in the form of a solution or dispersion in a liquid medium.

18. The method according to claim 1 , wherein the coating formulation is in the form of a medium comprising one or more of water, an alcohol ether, an alcohol, an aliphatic hydrocarbon, and an ester.