Manganese complex drier for coating compositions

1. A drier for an air drying auto-oxidisable resin composition comprising a transition metal complex having a cation of the following structure I:

wherein,

R═C1-C20 alkyl optionally substituted with heteroatoms, C6-C20 aryl optionally substituted with heteroatoms, or a residue of an acid functional polymer;

R 1 ═H, C1-C20 alkyl optionally substituted with heteroatoms, C6-C20 aryl optionally substituted with heteroatoms;

X═O or OC(R 2 )O, wherein a+=4+ when X═O, and a+=3+ when X═OC(R 2 )O, and

R 2 ═C1-C20 alkyl optionally substituted with heteroatoms, C6-C20 aryl optionally substituted with heteroatoms, or a residue of an acid functional polymer.

2. The drier according to claim 1 , wherein the transition metal complex has a cation of the following structure II:

3. The drier according to claim 1 , wherein the transition metal complex has a cation of the following structure III:

4. The drier according to claim 1 , wherein a counterion of the transition metal complex a) is a monoanion or a dianion.

5. The drier according to claim 1 , wherein a counterion of the transition metal complex a) is a monoanion selected from the group consisting of carboxylates R 3 CO 2 − , in which R 3 ═C1-C20 alkyl substituted with heteroatoms, C6-C20 aryl optionally substituted with heteroatoms, PF 6 − , SbF 6 − , AsF 6 − , BF 4 − , ClO 4 − , NO 3 − and B(C 6 F 5 ) 4 − .

6. The drier according to claim 1 , wherein R 1 ═C1-C6 alkyl.

7. An air drying auto-oxidative resin composition comprising:

(a) a drier comprising the transition metal complex according to claim 1 , and

(b) a polymer comprising unsaturated fatty acid residues.

8. The composition according to claim 7 , wherein the polymer (b) is selected from the group consisting of alkyds, vinyl polymers, polyurethane resins, hyperbranched resins and mixtures thereof.

9. The composition according to claim 7 , wherein the amount of the cation of the transition metal complex (a) is in the range from 0.00001 wt % to 5 wt % based on the total solids content of the polymer (b).

10. The composition according to claim 7 , wherein the transition metal complex has a cation of the following structure II:

11. The composition according to claim 7 , wherein the transition metal complex has a cation of the following structure III:

12. The composition according to claim 7 , wherein a counterion of the transition metal complex a) is a monoanion or a dianion.

13. The composition according to claim 7 , wherein a counterion of the transition metal complex is a monoanion selected from the group consisting of carboxylates R 3 CO 2 − , in which R 3 ═C1-C20 alkyl substituted with heteroatoms, C6-C20 aryl optionally substituted with heteroatoms, PF 6 − , SbF 6 − , AsF 6 − , BF 4 − , ClO 4 − , NO 3 − and B(C 6 F 5 ) 4 − .

14. The composition according to claim 7 , wherein R 1 ═C1-C6 alkyl.

15. A coating composition comprising the auto-oxidisable resin composition according to claim 7 .

16. The coating composition according to claim 15 , wherein the coating composition is a paint, lacquer, ink or varnish.

17. A method of coating a substrate comprising:

(i) applying the coating composition according to claim 15 onto a substrate, and

(ii) drying the composition in the presence of air to obtain a coating on the substrate.

18. A substrate coated with the coating composition according to claim 15 .