Crosslinkable composition crosslinkable with a latent base catalyst

1. A crosslinkable polymer composition comprising reactive components A and B each comprising at least 2 reactive groups wherein the at least 2 reactive groups of component A are acidic protons (C—H) in activated methylene or methine groups and the at least 2 reactive groups of component B are activated unsaturated groups (C═C) to achieve crosslinking by Real Michael Addition (RMA), wherein the component A is a malonate containing component and wherein components A and B react on drying of the crosslinkable polymer composition by deblocking of latent base catalyst C by evaporation of carbon dioxide, which latent base crosslinking catalyst, is a substituted carbonate salt according to formula 1

wherein X + represents a non acidic cation and wherein R is hydrogen, alkyl, aryl or aralkyl group.

2. The crosslinkable composition according to claim 1 , wherein the component A or B or both each independently are a polymer, oligomer, dimer or monomer molecule and wherein at least one of components A, B and C are on separate molecules or combined in one or more molecules.

3. The crosslinkable composition according to claim 1 wherein the malonate component A is an oligomer or polymer wherein the polymer comprises a polyester, polyurethane, polyether, polyacrylic or polycarbonate or mixtures, blends or hybrids thereof.

4. The crosslinkable composition according to claim 1 , wherein the component B comprises two or more unsaturated acryloyl, maleate, methacryloyl or fumarate functional groups.

5. The crosslinkable composition according to claim 1 , wherein the malonate component A comprises a number average of 2 to 20 reactive acidic protons (C—H).

6. The crosslinkable composition according to claim 1 , wherein the ratio of the number of acidic protons (C—H) in malonate component A to the number of activated unsaturated groups (C═C) on component B is in the range between 10 and 0.1.

7. The crosslinkable composition according to claim 1 , comprising in addition to the malonate component A, a second component A2 comprising reactive acidic protons having a higher acidity than component A and also is reactive towards component B.

8. The crosslinkable composition according to claim 7 , wherein the second acidic component A2 is a C—H acidic component reactive towards component B with an RMA reaction.

9. The crosslinkable composition according to claim 8 , wherein the second acidic component A2 is an activated methylene compound according to formula 2

wherein R is hydrogen or an alkyl, aralkyl or aryl substituent and Y and Y′ are same or different substituent groups, or wherein at least one of the —C(═O)—Y and —C(═O)—Y′ is replaced by CN or phenyl and wherein A2 has higher acidity than malonate by choice of at least one of: a different R, a different Y, and a different Y′.

10. The crosslinkable composition according to claim 9 wherein component A2 is an acetoacetate or acetylacetone containing component.

11. The crosslinkable composition according to claim 7 , wherein the pKa of component A2 is between 0.5 and 6 units lower than the pKa of malonate component A.

12. The crosslinkable composition according to claim 7 , wherein the amount of reactive acid protons in component A2 is between 0.1 and 50 mole % of the total mole of reactive acid protons in components A and A2.

13. The crosslinkable composition according to claim 7 , wherein the reactive C—H functionality of component A2 is lower than the C—H functionality of malonate component A.

14. The crosslinkable composition according to claim 1 , comprising an organic solvent wherein at least part of the solvent is an primary alcohol wherein the alcohol is present in an amount of at least 1 and at most 45 wt % relative to the total weight of the crosslinkable composition and wherein the alcohol is a primary mono-alcohol having 1-20 carbon atoms.

15. The crosslinkable composition according to claim 14 , wherein the alcohol is a primary mono-alcohol having 1 to 20 carbon atoms.

16. The crosslinkable composition according to claim 1 , further comprising 0.1-10 wt % of water (relative to total weight of the crosslinkable composition).

17. The crosslinkable composition according to claim 1 , comprising the latent crosslinking catalyst in an amount ranging between 0.001 and 0.3 meq/g solids (meq/g solids defined as moles latent base relative to the total dry weight of the crosslinkable composition).

18. The crosslinkable composition according to claim 1 , wherein the cation in the latent crosslinking catalyst is a quaternary ammonium or phosphonium carbonate salt according to formula 3,

wherein Y represents N or P, and wherein:

each R′ is a same or different alkyl, aryl or aralkyl group or a polymer,

R is hydrogen, alkyl, aryl or aralkyl group or a polymer, or a bridged ring structure with R′.

19. The crosslinkable composition according to claim 1 in the form of a set of separate unmixed precursor compositions wherein one precursor composition comprises components A and B and another precursor composition comprises the latent crosslinking catalyst composition.

20. The crosslinkable composition according to claim 1 , wherein the crosslinkable components in the composition are a binder in a coating composition, further comprising one or more coating additives.

21. The crosslinkable composition according to claim 20 , having a solids content between 55 and 100% and 0 to 45 wt % solvent having a dry to touch time at room temperature between 5 to 120 min and a gel time of at least 3 hours at room temperature.

22. Coating layers comprising a cured coating composition according to claim 20 .