Low voc additives for extending the wet edge and open time of aqueous coatings
Disclosed is a low VOC coating additive employing a water-dispersible polymer, a water insoluble plasticizer, cyclohexanedimethanol, and optionally an amphiphilic component. The additive can be added to a coating to improve at least one performance characteristics of the coating, such as, wet-edge time, open time, scrub resistance, wet adhesion, and water resistance.
1. An additive composition for extending the open-time of an aqueous composition comprising
a) from about 30 to about 65 weight percent of a water-dispersible polymer, based on the total weight of solids in said additive, said water-dispersible polymer having a Tg in the range of from about 20° C. to about 160° C.,
b) from about 5 to about 40 weight percent of a water-insoluble plasticizer, based on the total weight of solids in said additive, said water-insoluble plasticizer having a molecular weight of less than about 1,000 g/mole and comprises an ester of a glycol, a triol, and/or a polyol; an ester of monofunctional aromatic carboxylic acid and a monofunctional alcohol; an ester of a dicarboxylic acid and/or a tricarboxylic acid; an ether of a glycol, or a triol, and/or a polyol; or mixtures thereof; and
c) from about 30 to about 65 weight percent cyclohexanedimethanol, based on the total weight of solids in said additive,
wherein said additive composition is an aqueous dispersion and has a VOC content of less than about 20 weight percent based on the total weight of said additive.
2. The additive of claim 1 , wherein said additive further comprises an amphiphilic component.
3. The additive of claim 2 , wherein said additive comprises in the range of from about 2 to about 40 weight percent of said amphiphilic component based on the total weight of solids in said additive.
4. The additive of claim 1 , wherein said water-dispersible polymer comprises a neutralized vinyl polymer and/or a sulfopolymer.
5. The additive of claim 4 , wherein said neutralized vinyl polymer comprises the residue of at least one monomer having a carboxylic acid end group and/or an anhydride end group.
6. The additive of claim 5 , wherein said neutralized vinyl polymer further comprises the residue of styrene, methyl methacrylate, butyl acrylate, butyl methacrylate, isobutyl methacrylate, and/or 2-ethylhexyl acrylate.
7. The additive of claim 4 , wherein said sulfopolymer comprises the residue of a sulfomonomer having at least one metal sulfonate moiety.
8. The additive of claim 7 , wherein said sulfomonomer is 5-sodiosulfoisophathalic acid.
9. The additive of claim 4 , wherein said sulfopolymer comprises a sulfopolyester, a sulfopolyamide, and/or a sulfopolyesteramide.
10. The additive of claim 2 , wherein said amphiphilic component comprises a surfactant and/or an amphiphilic polyester.
11. A coating comprising: water; a binder; said additive of claim 1 , and optionally, an amphiphilic component.
12. A coating comprising: water; a binder; and said additive of claim 1 , wherein said coating has a wet edge time of at least about 1.5 minutes, a scrub resistance of at least about 500 cycles, a wet adhesion of at least about 3, and a water resistance of at least about 3.