Water-based compositions with long term gloss retention
Water-based coating compositions or paint having improved gloss retention, including a latex or water-dispersible polymer, a UV-VIS absorber comprising a substituted benzophenone capable of being a free radical generator, a hindered amine light stabilizer, and optionally a low-VOC coalescent provided in a preferably desired amount. A composition comprising a blend a UV-VIS absorber comprising a substituted benzophenone capable of being a free radical generator, a hindered amine light stabilizer, and a low-VOC coalescent, providing a thermally-stable coalescent that can be used in a paint formulation for gloss retention. Gloss retention of paints containing the UV-VIS absorber and hindered amine light stabilizer being markedly improved over paints that do not have both components present.
1. A composition, comprising:
a latex polymer comprising at least one ethylenically unsaturated monomer dispersed in an aqueous medium;
one or more UV-VIS absorbers, wherein the one or more UV-VIS absorbers comprises a substituted benzophenone capable of being a free radical generator, wherein the substituted benzophenone is phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, ethyl-2,4,6-trimethylbenzoylphenylphosphinate, 2,4,6-trimethylbenzophenone, 4-methylbenzophenone, 4-phenylbenzophenone, 2,2-dimethoxy-1,2-diphenylethanone, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, isopropylthioxanthone, methyl-o-benzoyl-benzoate, methylbenzoylformate, benzoin ethyl ether, 4′-ethoxyacetophenone, 4,4-bis(diethylamino)benzophenone, 2,2-dimethoxy-2-phenylacetephenone, 2-hydroxy-2-methylpropiophenone, 2-benzyl-2-(diemthylamino)-4′-morpholinobutryophenone, 4-methylbenzophenone, benzophenone hydrazone, or a combination thereof;
one or more hindered amine light stabilizers; and
optionally one or more low-VOC coalescents;
wherein the one or more UV-VIS absorbers and the one or more hindered amine light stabilizers are present in the composition in a total combined weight of at least 0.5 wt-% based upon the total polymer solids in the composition;
wherein the one or more UV-VIS absorbers and the one or more hindered amine light stabilizers are present in a weight ratio of about 1:9 to about 7:3 (UV-VIS absorbers:hindered amine light stabilizers); and
wherein the composition is suitable for use in a paint and one or more of the following is true:
when the composition is used in a paint, applied to a substrate, and allowed to dry to form a dried film, the dried film has an improved din pick-up resistance by at least 10%, relative to the same composition without the one or more UV-VIS absorbers and the one or more hindered amine light stabilizers, based on a change in ΔE values;
when the composition is used in a paint, applied to a substrate, and allowed to dry to form a dried film, the dried film has an initial minimum gloss rating of at least 20 (satin-like), at least 35 (traditional semi-gloss), at least 70 (traditional gloss/high gloss architectural), or at least 85 (high gloss) units with a 60-degree gloss meter;
when the composition is used in a paint, applied to a substrate, and allowed to dry to form a dried film, the dried film has a gloss retention of less than a 10 unit drop over 2000 hours measured at 60-degree gloss according to ASTM G154, using Cycle 1 as listed in the standard; and/or
when the composition is used in a semi-glossy or glossy finish paint, applied to a substrate, and allowed to dry to form a dried film, the dried film has at least 80% gloss retention, the gloss retention being after at least 2000 hours measured by QUVA gloss retention at 60-degree gloss according to ASTM G154, using Cycle 1 as listed in the standard.
2. The composition of claim 1 , wherein the composition is an architectural paint.
3. The composition of claim 1 , wherein the one or more UV-VIS absorbers comprises methyl-o-benzoyl-benzoate.
4. The compositiono of claim 1 , wherein the one or more UV-VIS absorbers comprises 2,2-dimethoxy-2-phenylacetephenone.
5. The composition of claim 1 , wherein the composition is substantially free of benzophenone.
6. The composition of claim 1 , wherein the one or more UV-VIS absorbers is capable of absorbing radiation within a range of 240-465 nm.
7. The composition of claim 1 , wherein the one or more hindered amine light stabilizers comprises a tetramethylpiperidine derivative.
8. The composition of claim 1 , wherein the one or more low-VOC coalescents is present and has a volatile organic content of 15 wt-% or less.
9. The composition of claim 1 , wherein the one or more low-VOC coalescents have the formula:
R 1 —(C(O)—X r —O) n —R 2
wherein:
R 1 is an organic group;
X is a divalent organic group;
r is 0 or 1;
n is 1 to 10; and
R 2 is hydrogen or an organic group;
with the proviso that R 1 includes at least three carbon atoms when X is not —(CH 2 ) s — wherein s is 2 to 8;
with the proviso that the one or more low-VOC coalescents have less than two aliphatic unsaturated carbon-carbon bonds when r is zero.
10. The composition of claim 1 , wherein the composition is in the form of a liquid solution and less than 1 wt-% of the UV-VIS absorber precipitates out of the liquid solution when stored for at least 30 days at a temperature of about −20° C. or below.
11. The composition of claim 1 , wherein the composition is capable of being used in a formulation to form an architectural finish paint.
12. The composition of claim 1 , wherein the composition includes less than about 50 g/L of VOC.
13. The composition of claim 1 , wherein when the composition is used in a paint, applied to a substrate, and allowed to dry to form a dried film, the dried film has an improved dirt pick-up resistance by at least 10%, relative to the same composition without the one or more UV-VIS absorbers and the one or more hindered amine light stabilizers, based on a change in ΔE values.
14. The composition of claim 1 , wherein when the composition is used in a paint, applied to a substrate, and allowed to dry to form a dried film, the dried film has an initial minimum gloss rating of at least 20 (satin-like), at least 35 (traditional semi-gloss), at least 70 (traditional gloss/high gloss architectural), or at least 85 (high gloss) units with a 60-degree gloss meter.
15. The composition of claim 1 , wherein when the composition is used in a paint, applied to a substrate, and allowed to dry to form a dried film, the dried film has a gloss retention of less than a 10 unit drop over 2000 hours measured at 60-degree gloss according to ASTM G154, using Cycle 1 as listed in the standard.
16. The composition of claim 1 , wherein when the composition is used in a semi-glossy or glossy finish paint, applied to a substrate, and allowed to dry to form a dried film, the dried film has at least 80% gloss retention, the gloss retention being after at least 2000 hours measured by QUVA gloss retention at 60-degree gloss according to ASTM G154, using Cycle 1 as listed in the standard.