UV-curable coating composition having improved sunlight stability
Disclosed is a radiation curable coating composition, including polymerizable, unsaturated compounds such as (meth)acrylates, vinyl compounds, or the like in a concentration range of 15-98% by weight, with an addition of 5-35% by weight, preferably 5-20% by weight, of organic UV absorber(s), wherein the UV absorber(s) has/have its/their maximum absorption coefficient in a wavelength range of <390 nm, preferably <350 nm, wherein the coating composition optionally includes other components in the amount of the balance to 100% by weight, and a method for curing such a coating composition. Also disclosed is a coating composition of this kind, wherein the organic UV absorber is radically polymerizable.
1. A radiation-curable coating composition comprising pigments, at least one polymerizable, unsaturated compound in a concentration range of 15-98% by weight and 5-35% by weight of one or more organic UV absorber wherein the UV absorber(s) has/have a maximum absorption coefficient in a wavelength range of <350 nm.
2. The radiation-curable coating composition of claim 1 , wherein the polymerizable, unsaturated compound is a (meth)acrylate or vinyl compound.
3. The radiation-curable coating composition of claim 1 , further defined as comprising 5-20% by weight organic UV absorber(s).
4. The radiation-curable coating composition of claim 1 , wherein at least one organic UV absorber is radically polymerizable.
5. The radiation-curable coating composition of claim 4 , wherein the coating composition includes other components in an amount of a balance to 100% by weight.
6. The radiation-curable coating composition of claim 5 , further defined as comprising at least one or more of a photoinitiator, photosensitizer, bulking agent, additive and/or other UV absorber in a total concentration range of 0-80% by weight.
7. The radiation-curable coating composition of claim 6 , further defined as comprising at least one photosensitizer and/or photoinitiator with an absorption maximum in a range of less than 420 nm.
8. The radiation-curable coating composition of claim 7 , wherein the at least one photosensitizer and/or photoinitiator has an absorption maximum in a range of greater than 350 nm.
9. The radiation-curable coating composition of claim 1 , comprising a proportion of monofunctional polymerizable components that is at least 50% by weight of all polymerizable components of the composition.
10. The radiation-curable coating composition of claim 9 , wherein the proportion of monofunctional polymerizable components is at least 75% by weight of all polymerizable components of the composition.
11. The radiation-curable coating composition of claim 1 , comprising a proportion of monofunctional polymerizable components that is at most 25% by weight of all polymerizable components of the composition.
12. The radiation-curable coating composition of claim 1 , further defined as an ink.
13. The radiation-curable coating composition of claim 12 , further defined as inkjet ink.
14. A method for curing a coating composition comprising:
obtaining a radiation-curable coating composition of claim 1 ; and
curing the radiation-curable coating composition with a light source having an emission peak of >350 nm.
15. The method of claim 14 , wherein the light source is a UV/LED lamp or a UV/LD lamp having an emission peak of >360 nm.
16. The method of claim 15 , wherein the light source has an emission peak of >390 nm.
17. A coating produced by curing a radiation-curable coating composition of claim 1 .