Liquid two-component coating compositions
The invention relates to two-component liquid coating composition comprising: A) at least one compound with functional groups reactive towards reactive functional groups of cross-linking agent B), B) at least one cross-linking agent with reactive functional groups and C) at least one catalyst compound having at least one urethane and/or at least one urea group and at least one tertiary amine group, said catalyst compound is present as particles having a melting temperature of 40 to 180° C.
1. Two-component liquid coating composition comprising:
A) at least one compound with functional groups reactive towards reactive functional groups of cross-linking agent B),
B) at least one cross-linking agent with reactive functional groups and
C) at least one catalyst compound having at least one urethane and/or at least one urea group and at least one tertiary amine group, said catalyst compound is present as particles having a melting temperature of 40 to 180° C., wherein said catalyst compound is prepared by reacting a) at least one polyisocyanate with b) at least one polyol and/or with c) at least one tertiary amine compound having at least one group capable of addition with isocyanate, wherein
the at least one catalyst compound C) is present as particles and wherein the particles have an average particle size, as determined by means of laser diffraction, of 1 to 100 μm.
2. The coating composition of claim 1 , wherein the at least one catalyst compound C) has a melting temperature of 60 to 160° C.
3. The coating composition of claim 1 , wherein the solubility of the at least one catalyst compound C) is less than 10 g per liter of butyl acetate at 20° C.
4. The coating composition of claim 1 , wherein the catalyst compound C) is a solid catalyst compound and the particles of the solid catalyst compound are formed by grinding of the at least one solid catalyst compound C) or by hot dissolution of the at least one catalyst compound C) in a dissolution medium and subsequent catalyst compound C) particle formation during and/or after cooling.
5. The coating composition of claim 1 , wherein said polyol is a diol.
6. The coating composition of claim 1 , wherein the polyisocyanate a) comprises at least one polyisocyanate selected from a group consisting of 1,6-hexane diisocyanate, diphenylmethane diisocyanate, the isocyanurate of 1,6-hexane diisocyanate, the isocyanurate of diphenylmethane diisocyanate and combinations thereof.
7. The coating composition of claim 1 , wherein the at least one polyol is a diol and wherein the diol b) is a diol component that is formed by at least one linear aliphatic alpha,omega-C2-C12-diol, and 0 to 80 mol % by at least one diol that is different from linear aliphatic alpha,omega-C2-C12-diols, wherein the mol % of the respective diols add up to 100 mol %.
8. The coating composition of claim 1 , wherein the tertiary amine compound c) is an amine compound selected from the group consisting of hydroxyl amine, thiol amine, diamine with a secondary or primary amino group, polyamine with at least two primary amino groups and/or with at least two secondary amino groups, and combinations thereof.
9. The coating composition of claim 1 , wherein the at least one catalyst compound C) is a compound which is prepared by reacting a) at least one diisocyanate, with b) at least one diol component and with c) at least one tertiary amine compound c) having at least one group capable of addition with isocyanate, wherein the diisocyanate component is formed by 1,6-hexane diisocyanate and/or diphenylmethane diisocyanate, and 20 to 50 mol % by one or two diisocyanates, each forming at least 10 mol % of the diisocyanate component and being selected from the group consisting of toluylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, trimethylhexane diisocyanate, cyclohexane diisocyanate, cyclohexanedimethylene diisocyanate and tetramethylenexylylene diisocyanate, wherein the mol % of the respective diisocyanates add up to 100 mol %, wherein 20 to 100 mol % of the diol component is formed by at least one linear aliphatic alpha,omega-C2-C12-diol, and 0 to 80 mol % by at least one diol that is different from linear aliphatic alpha,omega-C2-C12-diols, wherein the mol % of the respective diols add up to 100 mol %.
10. The coating composition of claim 1 , wherein the catalyst compound C) is present in an amount of 2 to 10% by weight, relative to the entire coating composition.
11. The coating composition of claim 1 , wherein the compound A) comprises compounds selected from the group consisting of hydroxyl-functional, thiol-functional, epoxy-functional, silane-functional compounds and combinations thereof.
12. The coating composition of claim 1 , wherein the cross-linking agent B) comprises polyisocyanates with free isocyanate groups and/or carboxyl groups.
13. The coating composition of claim 1 , wherein the compound A) comprises compounds with hydroxyl groups and/or thiol groups and cross-linking agent B) comprises polyisocyanates with free isocyanate groups.
14. A process for the preparation of a coating layer, comprising the successive steps:
1) applying a coating layer from a coating composition of claim 1 onto uncoated or precoated substrate,
2) optionally, flashing off the applied coating layer to remove organic solvent and/or water, and
3) thermally curing the coating layer at an object temperature above the melting temperature of the at least one said catalyst compound C).
15. The process of claim 14 , wherein the coating layer is selected from the group consisting of a primer layer, a surfacer layer, an outer clear top coat layer, a pigmented single-stage top coat layer and a transparent sealing layer.
16. The process of claim 14 , wherein the coatings layer is industrial coating, original automotive coating or automotive repair coating of automotive bodies and automotive body parts.