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 method of preparing an aqueous coating composition, the method comprising:
providing a latex polymer dispersed in an aqueous medium, wherein the latex polymer comprises at least one ethylenically unsaturated monomer;
providing one or more UV-VIS absorbers, wherein the one or more UV-VIS absorbers comprises a substituted benzophenone that is 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-(dimethylamino)-4′-morpholinobutryophenone, 4-methylbenzophenone, benzophenone hydrazone, or a combination thereof;
providing one or more hindered amine light stabilizers;
optionally providing one or more low-VOC coalescents; and
combining the polymer, the one or more UV-VIS absorbers, the one or more hindered amine light stabilizers, and optionally the low-VOC coalescent;
wherein at least one of the following is true:
the one or more UV-VIS absorbers and the one or more hindered amine light stabilizers are present in the coating composition in a total combined weight of at least 0.5 wt-% based upon the total resin solids of the coating composition; or
the one or more UV-VIS absorbers and the one or more hindered amine light stabilizers are present in the coating composition in a weight ratio of about 1:9 to about 7:3 UV-VIS absorbers.
2 . The method of claim 1 , wherein the polymer is formed from at least two ethylenically unsaturated monomers comprising acrylic acid, C 1 -C 8 esters of acrylic acid, substituted C 1 -C 8 esters of acrylic acid, methacrylic acid, C 1 -C 8 esters of methacrylic acid, substituted C 1 -C 8 esters of methacrylic acid, styrene, α-methyl styrene, vinyl toluene, vinyl acetate, vinyl propionate, allyl methacrylate, or combination thereof.
3 . The method of claim 1 , wherein the polymer comprises a multistage latex polymer having a first stage with a Tg of about 25° C. to about 90° C. and a second stage with a Tg of about −15° C. to about 10° C., the Tg values calculated by the Fox Equation.
4 . The method of claim 1 , wherein the polymer comprises a multistage latex polymer having a first stage with a Tg that differs from a second stage with a Tg by at least about 35° C., the Tg values calculated by the Fox Equation.
5 . The method of claim 1 , wherein the polymer comprises a latex polymer having at least one Tg within a range of −20° C. to 70° C., the Tg value calculated by the Fox Equation.
6 . The method of claim 1 , wherein the polymer comprises a latex polymer having at least one Tg within a range of −15° C. to 60° C., the Tg value calculated by the Fox Equation.
7 . The method of claim 1 , wherein the polymer comprises a latex polymer having at least one Tg within a range of −10° C. to 30° C., the Tg value calculated by the Fox Equation.
8 . The method of claim 1 , wherein the polymer comprises a multistage latex polymer polymerized from a first mixture of monomers for a first stage and a second mixture of monomers for a second stage, the first mixture comprising methyl methacrylate, butyl acrylate, methacrylic acid, a ureido-functional monomer, and optionally diacetone acrylamide, and the second mixture comprising methyl methacrylate, butyl acrylate, an acid-functional ethylenically unsaturated monomer, optionally diacetone acrylamide, and a ureido-functional monomer.
9 . The method of claim 1 , wherein the polymer comprises a single stage latex polymer.
10 . The method of claim 1 , wherein the coating composition is substantially free of benzophenone.
11 . The method of claim 1 , wherein the one or more UV-VIS absorbers is capable of absorbing radiation within a range of 240-465 nm.
12 . The method of claim 1 , wherein the one or more hindered amine light stabilizers comprises a tetramethylpiperidine derivative.
13 . The method of claim 1 , wherein the coating composition is an architectural paint.
14 . The method of claim 1 , wherein the one or more UV-VIS absorbers comprises methyl-o-benzoyl-benzoate.
15 . The method of claim 1 , wherein the one or more UV-VIS absorbers comprises 2,2-dimethoxy-2-phenylacetephenone.
16 . The method of claim 1 , wherein the coating composition includes less than about 50 g/L of volatile organic compounds (VOC).
17 . The method of claim 1 , wherein the coating composition applied to a substrate and allowed to dry as a film has at least 80% gloss retention after at least 2000 hours measured by QUVA gloss retention at 60-degree gloss according to ASTM G154, cycle 1.
18 . A method of preparing an aqueous coating composition, the method comprising:
providing a latex polymer dispersed in an aqueous medium, wherein the latex polymer comprises at least one ethylenically unsaturated monomer;
providing one or more UV-VIS absorbers, wherein the one or more UV-VIS absorbers comprises a substituted benzophenone that is capable of being a free radical generator, wherein the substituted benzophenone comprises Formula (I):
wherein A is an oxygen atom or N—NH 2 ;
wherein n is 0 or 1, m is 0 or 1, and y is 0 to 5, with the proviso that n, m and y are each 0 when A is N—NH 2 ;
wherein R 1 and R 2 , if present, independently from each other comprise an organic linking group;
wherein R 3 comprises an alkanoyloxy group, C 1 -C 3 alkyl, diethylaminogroup, or a 6-membered nitrogen and oxygen-containing saturated heterocyclic group; and
wherein X is a phenyl group, hydroxy-2-methyl-propyl group, an alkanoyloxy group, or a phospine oxide group, with the proviso that when X comprises a phenyl group then the total of m, n and y is ≥1;
providing one or more hindered amine light stabilizers;
optionally providing one or more low-VOC coalescents; and
combining the polymer, the one or more UV-VIS absorbers, the one or more hindered amine light stabilizers, and optionally the low-VOC coalescent;
wherein at least one of the following is true:
the one or more UV-VIS absorbers and the one or more hindered amine light stabilizers are present in the coating composition in a total combined weight of at least 0.5 wt-% based upon the total resin solids of the coating composition; or
the one or more UV-VIS absorbers and the one or more hindered amine light stabilizers are present in the coating composition in a weight ratio of about 1:9 to about 7:3 UV-VIS absorbers.
19 . A method of preparing an aqueous coating composition, the method comprising:
providing a latex polymer dispersed in an aqueous medium, wherein the latex polymer comprises at least one ethylenically unsaturated monomer;
providing one or more UV-VIS absorbers, wherein the one or more UV-VIS absorbers comprises a substituted benzophenone that is capable of being a free radical generator, wherein the substituted benzophenone comprises Formula (II):
wherein A is an oxygen atom or N—NH 2 ;
wherein n is 0 or 1, m is 0 or 1, y is 0 to 5, and z is 0 to 5, with the proviso that n, m, y and z are each 0 when A is N—NH 2 and with the further proviso that the total of n, m, y and z is ≥1 when A is an oxygen atom;
wherein R 1 and R 2 , if present, independently from each other comprise an organic linking group;
wherein R 3 , and R 4 , if present, independently from each other an alkanoyloxy group, C 1 -C 3 alkyl, diethylaminogroup, a 6-membered nitrogen and oxygen-containing saturated heterocyclic group, or form a bridge comprising an S atom;
providing one or more hindered amine light stabilizers;
optionally providing one or more low-VOC coalescents; and
combining the polymer, the one or more UV-VIS absorbers, the one or more hindered amine light stabilizers, and optionally the low-VOC coalescent;
wherein at least one of the following is true:
the one or more UV-VIS absorbers and the one or more hindered amine light stabilizers are present in the coating composition in a total combined weight of at least 0.5 wt-% based upon the total resin solids of the coating composition; or
the one or more UV-VIS absorbers and the one or more hindered amine light stabilizers are present in the coating composition in a weight ratio of about 1:9 to about 7:3 UV-VIS absorbers.