Coating material, related production method and use
A coating material comprising (A) at least one kind of hydrophobic nanoparticles based on silica and (B) at least one kind of hydrophilic nanoparticles based on silica having a BET internal surface area of >300 m 2 /g; process for preparing it, and its use.
1. A coating material comprising
(A) at least one hydrophobic nanoparticles based on silica and
(B) at least one hydrophilic nanoparticles based on silica having a BET internal surface area of >300 m 2 /g,
wherein the coating material comprises the nanoparticles (A) and (B) in an amount of from 0.8 to 3% by weight, based on the overall solids content of the coating material.
2. The coating material of claim 1 , wherein the hydrophilic nanoparticles (B) have a BET internal surface area of >340 m 2 /g.
3. The coating material of claim 1 , wherein the weight ratio of hydrophobic nanoparticles (A) to hydrophluc nanoparticles (B) is from 1:4 to 4:1.
4. The coating material of claim 3 , wherein the (A):(B) weight ratio is from 3:7 to 7:3.
5. The coating material of claim 4 , wherein the (A):(B) weight ratio is from 2:3 to 3:2.
6. The coating material of claim 1 wherein the primary particle size of the nanoparticles (A) and (B) is <35 nm.
7. The coating material of claim 6 , wherein the primary particle size is <20 nm.
8. The coating material of claim 7 , wherein the primary particle size is <10 nm.
9. The coating material of claim 1 , wherein the hydrophobic nanoparticles (A) are obtained by surface modification of pyrogenic silica.
10. The coating material of claim 1 , wherein the hydrophilic nanoparticies (B) comprise pyrogenic silica.
11. The coating material as claimed in claim 1 , comprising the nanoparticies (A) and (B) in an amount of from 1 to 2.4% by weight, based on the overall solids content of the coating material.
12. A process for preparing the coating material of claim 1 comprising mixing and homogenizing the hydrophobic nanoparticles (A) and the hydrophilic nanoparticles (B) in the form of pigment pastes with the other constituents.
13. A process for preparing a scratch-resistant coated surface, comprising applying the coating material of claim 1 to a surface.
14. The process of claim 13 wherein the coating material of claim 1 is in the form of a molding or a film.
15. The process of claim 13 wherein the coating material is at least one component of an automotive multicoat paint system.