Silane-based coating composition

1 . A coating composition comprising

(A) one or more resins of formula (I)

R—[NH—CO—NR 1 —R 2 —Si(R a ) 3-x (R b ) x ] y   (I)

wherein:

R is an aliphatic hydrocarbyl group, optionally containing one or more moieties selected from the group consisting of isocyanurate groups, uretdione groups, iminooxadiazinedione groups, allophanate groups and biuret groups;

R 1 is an alkyl group containing 1 to 10 carbon atoms,

R 2 is an alkylene group containing 1 to 6 carbon atoms,

R a is an alkoxy group containing 1 to 4 carbon atoms,

R b is an alkyl group containing 1 to 4 carbon atoms or an alkoxy group containing 1 to 4 carbon atoms,

x is 0 or 1, and

y is 2 to 5; and

wherein the one or more resins of formula (I) have an NCO content of 0%;

(B) one or more catalysts of formula (II)

z [H 3 C—C(R c )(R d )—C(═O)—O − ]M z+   (II)

wherein

R c and R d independently are hydrogen or alkyl groups containing 1 to 6 carbon atoms, with the proviso that the sum of the number of carbon atoms in residues R c and R d ranges from 2 to 7; and z=1 to 4; with the proviso that,

if z=1, then M is selected from the group consisting of Li, K and Na;

if z=2, then M is selected from the group consisting of Zn and Zr;

if z=3, then M is selected from the group consisting of Bi and Al;

if z=4, then M is selected from the group consisting of Zr and Ti; and

(C) one or more aprotic organic solvents.

2 . The coating composition according to claim 1 , characterized in that in formula (I)

R is selected from the group consisting of a diisocyanate from which the isocyanate groups were formally subtracted or its oligomers from which the isocyanate groups were formally subtracted, and/or

R 1 is an alkyl group containing 2 to 8 carbon atoms, and/or

R 2 is an alkylene group containing 1 to 3 carbon atoms, and/or

R a is an alkoxy group containing 1 to 3 carbon atoms, and/or

R b is a methyl group or an alkoxy group having 1 or 2 carbon atoms, and/or

x=0, and/or

y=2 to 4.

3 . The coating composition according to claim 1 , characterized in that in formula (II) the sum of the number of carbon atoms in residues R c and R d ranges from 5 to 7 and/or z=1 or 3.

4 . The coating composition according to claim 1 , characterized in that the one or more catalysts of formula (II) are the neodecanoates and/or ethylhexanoates of potassium or lithium.

5 . The coating composition according to claim 1 , characterized in that the one or more aprotic organic solvents (C) are selected from the group consisting of aliphatic and/or aromatic hydrocarbons, ketones, esters, and mixtures of the afore-mentioned solvents.

6 . The coating composition according to claim 1 , characterized in that it further comprises one or more catalysts (B2) selected from the group consisting of bicyclic tertiary amines.

7 . The coating composition according to claim 1 , characterized in that it further comprises one or more carboxylic acids (D) of formula (III)

H 3 C—C(R e )(R f )—C(═O)—OH  (III)

wherein

R e and R f independently are hydrogen or alkyl groups containing 1 to 6 carbon atoms, with the proviso that the sum of the number of carbon atoms in residues R e and R f ranges from 2 to 7.

8 . The coating composition according to claim 1 , characterized in that it further comprises one or more epoxy functional compounds (E) of formula (IV)

(X) n —R 3 —Ox  (IV)

wherein Ox is an oxirane group; R 3 is an aliphatic hydrocarbyl group containing 2 to 15 carbon atoms and optionally comprising ether groups and/or ester groups; n=1 to 5; and the n X groups are independently of each other Ox or —Si(R g ) 3-v (R h ) v , wherein v=0 or 1, R g is an alkoxy group containing 1 to 4 carbon atoms, and R h is an alkyl group containing 1 to 4 carbon atoms or an alkoxy group containing 1 to 4 carbon atoms.

9 . The coating composition according to claim 1 , characterized in that it further contains one or more coating additives (F).

10 . The coating composition according to claim 1 , comprising

25 to 95 wt.-% of the (A) one or more resins of formula (I), based on the total weight of the coating composition;

1 to 50 mmol of the (B) one or more catalysts of formula (II) per 100 g of (A);

1 to 70 wt.-% of the (C) one or more aprotic solvents, based on the total weight of the coating composition;

0 to 80 wt.-% of (D) one or more carboxylic acids of formula (III)

H 3 C—C(R e )(R f )—C(═O)—OH  (III)

wherein

R e and R f independently are hydrogen or alkyl groups containing 1 to 6 carbon atoms, with the proviso that the sum of the number of carbon atoms in residues R e and R f ranges from 2 to 7, based on the total weight of (B);

0 to 20 wt.-% of (E) one or more epoxy functional compounds of formula (IV)

(X) n —R 3 —Ox  (IV)

wherein Ox is an oxirane group; R 3 is an aliphatic hydrocarbyl group containing 2 to 15 carbon atoms and optionally comprising ether groups and/or ester groups; n=1 to 5; and the n X groups are independently of each other Ox or —Si(R 8 ) 3-v (R h ) v , wherein v=0 or 1, R g is an alkoxy group containing 1 to 4 carbon atoms, and R h is an alkyl group containing 1 to 4 carbon atoms or an alkoxy group containing 1 to 4 carbon atoms, based on the solids content of the coating composition;

0 to 20 wt.-% of (F) one or more coating additives; and, if present,

catalyst (B2) in a weight ratio of (B) to (B2) being from 1:1 to 8:1.

11 . The coating composition of claim 1 , characterized in that it is a clearcoat composition.

12 . A method of coating a substrate with a coating composition, the method comprising

a. applying a coating composition as defined in claim 1 onto a substrate to form a coating layer; and

b. curing the coating layer at a temperature in the range from 10° C. to 180° C.

13 . A coated substrate obtained according to the method of claim 12 .

14 . The coated substrate according to claim 13 , characterized in that the substrate is selected from the group consisting of bodies of means of transportation or parts thereof; interior or exterior constructions; furniture; windows; doors; plastics moldings; small industrial parts; coils; containers; packaging; white goods; sheets; optical, electrical and mechanical components; glassware; and articles of everyday use.

15 . A multilayer coating comprising at least two coating layers, wherein at least one of the coating layers is formed from a coating composition according to claim 1 .

16 . A substrate coated with a multilayer coating as defined in claim 15 .