Tris(hydroxyphenyl) triazines
The instant invention relates to novel tris(hydroxyphenyl)triazines coating compositions, for instance automotive coating compositions, and to novel tris(hydroxyphenyl) triazines UV-absorbers having a long wavelength sifted absorption spectrum with significant absorbance up to 420 nm. Further aspects of the invention are a UV stabilized composition containing the novel UV-absorbers, a process for the stabilization of organic materials and coatings and the use of the compounds as UV-light stabilizers for organic materials and coatings.
1. An automotive coating composition comprising compound of formula (IIa)
wherein
R 1 , R 1 ′ and R 1 ″ are independently hydrogen, C 4 -C 24 alkyl, C 2 -C 18 alkenyl or C 5 -C 12 cycloalkyl; and
R 21 , R 21 ′ and R 21 ″ are independently C 4 -C 24 alkyl, C 2 -C 18 alkenyl or C 5 -C 12 cycloalkyl.
2. The automotive coating composition according to claim 1 ,
wherein
R 1 , R 1 ′ and R 1 ″ are independently hydrogen or C 4 -C 12 alkyl; and
R 21 , R 21 ′ and R 21 ″ are independently C 4 -C 12 alkyl.
3. The automotive coating composition according to claim 1 ,
wherein the compound of formula (IIa) is present in an amount of from 0.1% to 30% by weight, based on the weight of the coating composition.
4. An automotive coating obtained by applying the automotive coating composition of claim 1 on a substrate.
5. The automotive coating according to claim 4 , comprising the following layers
(d) a cathodically deposited coating, adhering to a metal substrate;
(e) at least one subsequent coating layer containing a compound of formula (IIa) adhering to the cathodically deposited coating; and
(f) a clear top coating containing one or more UV-absorbers different from those of formula (IIa) and optionally further light stabilizers.
6. The automotive coating according to claim 4 wherein the automotive coating is applied over a substrate, which is sensitive to electromagnetic radiation of wavelengths greater than 380 nm.
7. The automotive coating composition according to claim 1 , wherein
R 1 , R 1 ′ and R 1 ″ are independently C 4 -C 12 alkyl; and
R 21 , R 21 ′ and R 21 ″ are independently C 4 -C 12 alkyl.
8. A process for the stabilization of an automotive coating against the deleterious influence of UV and/or visible light, which comprises admixing and/or applying to said automotive coating as stabilizer a compound of formula (IIa) according to claim 1 .
9. A process according to claim 8 wherein the automotive coating comprises
(g) applying a cathodically deposited coating, adhering to a metal substrate
(h) incorporating into at least one coating adhering to the cathodically deposited coating a compound of formula (IIa); and
(j) applying a clear top coating over the coating adhering to the cathodically deposited coating, which clear top coating contains one or more UV-absorbers different from those of formula (IIa) and optionally further light stabilizers.
10. An automotive coating composition comprising the following compound
11. An automotive coating composition comprising the following compound