PROCESS FOR PRODUCING A MULTILAYER COATING

1 . A process for the multilayer coating of substrates comprising the following steps:

1. Applying a base coat layer of a water-based base coat composition containing color-imparting and/or special effect-imparting pigments onto an optionally precoated substrate,

2. Applying a clear coat layer of a transparent clear coat coating composition onto the base coat layer and

3. Curing the clear coat layer, wherein the transparent clear coat coating composition being an organic solvent-based coating composition comprising:

A) at least one binder with functional groups containing active hydrogen,

B) at least one polyisocyanate cross-linking agent with free isocyanate groups, and

C) at least one epoxy-functional silane of the general Formula (I):

X denoting the residues

with m being 1-4, or 3,4-epoxycyclohexyl,

R1, R2, R3 mutually independently meaning identical or different organic residues with 1 to 30 carbon atoms per molecule, providing that at least one of the residues is an alkoxy group with 1 to 4 carbon atoms and

n is 2, 3 or 4.

2 . The process according to claim 1 , wherein the transparent clear coat coating composition comprises 0.25 to 5.0% by weight solids of the epoxy-functional silane component C), relative to the sum of the solids content of component A) and component B).

3 . The process according to claim 2 , wherein the transparent clear coat coating composition comprises 1.0 to 3.0% by weight solids of the epoxy-functional silane component C), relative to the sum of the solids content of component A) and component B).

4 . The process according to any one of claims 1 to 3 , wherein n is 2 or 3.

5 . The process according to any one of claims 1 to 4 , wherein R1, R2 and R3 mutually independently mean identical or different alkoxy groups having 1-4 carbon atoms.

6 . The process according to any one of claims 1 to 5 , wherein the binder A) comprises at least one hydroxy-functional (meth)acrylic copolymer.

7 . The process according to any one of claims 1 to 6 , wherein the binder A) comprises at least one hydroxy-functional (meth)acrylic copolymer in combination with at least one hydroxy-functional oligoester.

8 . The process according to any one of claims 1 to 7 , wherein the at least one polyisocyanate cross-linking agent B) comprises a low-viscous polyisocyanate with a viscosity of 10 to 300 mPas.

9 . The process according to any one of claims 1 to 8 , wherein the water-based base coat composition is applied onto a filler layer.

10 . The process according to any one of claims 1 to 9 , wherein the water-based base coat composition is applied onto a filler layer of a filler coating composition comprising a hydroxy-functional binder component and a polyisocyanate cross-linking component.

11 . The process according to any one of claims 1 to 10 , wherein the substrate comprises vehicle bodies or parts thereof.

12 . Use of the process according to any one of claims 1 to 11 in vehicle repair coating.