Latex binders, aqueous coatings and paints having freeze-thaw stability and methods for using same
View Patent ↗Disclosed are latex polymers and an aqueous coating compositions having excellent freeze-thaw stability, open time, stain resistance, low temperature film formation, foam resistance, block resistance, adhesion, water sensitivity and a low-VOC content. The latex polymers and aqueous coating compositions include at least one latex polymer derived from at least one monomer copolymerized or blended with an alkoxylated compound, for example an alkoxylated tristyrylphenol or an alkoxylated tributylphenol. Also provided is an aqueous coating composition including at least one latex polymer, at least one pigment, water and at least one freeze-thaw additive. Typically, the freeze-thaw additive in an amount greater than about 1.3% by weight of the polymer, typically in an amount greater than about 2% by weight of the polymer, in an amount greater than about 4% by weight of the polymer, in an amount greater than about 7.5% by weight of the polymer, in an amount greater than about 10% by weight of the polymer or in an amount greater than about 20% by weight of the polymer.
1. A low VOC coating composition comprising at least one emulsion polymer prepared in the presence of at least one emulsifier according to structural formula:
wherein R 1 , R 2 and R 3 are independently selected from the group consisting of:
butyl, tert-butyl, isobutyl,
wherein:
X comprises a divalent hydrocarbon radical comprising a linear or branched alkylene radical having from about 2 to 8 carbon atoms; wherein n is an integer ranging from 1 to 100;
R 5 comprises —OH, —OCH 3 , —OC 2 H 5 , —OC 3 H 7 , —OC 4 H 9 , —OC 5 H 11 —OC 6 H 13 —Cl, —Br, —CN, sulfate (SO 4 −M + ), sulfonate (SO 3 −M + ), carboxylate (COO −M + ) a nonionic group, or a quaternary ammonium ion;
M+is a cation;
further wherein:
the emulsifier is present in an amount effective to increase the freeze-thaw stability of the coating composition, said amount comprising greater than about 20 % by weight of total monomer; and
the coating composition is a low VOC coating composition having a VOC content of less than about 100 g/L.
2. The coating composition of claim 1 , wherein the coating composition comprises a paint composition.
3. The coating composition of claim 1 , wherein n is an integer ranging from about 10 to about 60.
4. The coating composition of claim 1 , wherein n is an integer ranging from about 20 to about 50.
5. The coating composition of claim 1 , wherein the polymer has a glass transition temperature (Tg) ranging from about −15° C. to about 12° C.
6. The coating composition of claim 1 , wherein the polymer has a glass transition temperature (Tg) ranging from about −5° C. to about 0° C.
7. The coating composition of claim 1 , wherein the emulsifier comprises a compound of formula:
wherein:
n in an integer ranging from 1 to 100;
R 5 comprises —OH, —OCH 3 , —OC 2 H 5 , —OC 3 H 7 , —OC 4 H 9 , —OC 5 H 11 —OC 6 H 13 —Cl, —Br, —CN, sulfate (SO 4 −M + ), sulfonate (SO 3 −M + ), carboxylate (COO −M + a nonionic group, or a quaternary ammonium ion; and
M + is a cation.
8. The coating composition of claim 1 , wherein said composition comprises less than 2.0% of antifreeze agents based on the total weight of the composition.
9. The coating composition of claim 8 , wherein said composition comprises less than 0.1% of antifreeze agents based on the total weight of the composition.
10. The coating composition of claim 9 , wherein said composition does not comprise a coalescent agent.
11. The coating composition of claim 1 , wherein the composition has a VOC level of less than about 50 g/L.
12. The coating composition of claim 1 , wherein the at least one emulsion polymer comprises at least one monomer comprising acrylic acid, acrylic acid ester, methacrylic acid, methacrylic acid ester, or a mixture thereof.
13. The coating composition of claim 12 , wherein the emulsion polymer further comprises at least one monomer comprising styrene, alpha-methyl styrene, vinyl chloride, acrylonitrile, methacrylonitrile, ureido methacrylate, vinyl acetate, a vinyl ester of a branched tertiary monocarboxylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, ethylene, or a C 4 -C 8 , conjugated diene.