Varnish
A recording medium with an ink image thereon, wherein a varnish at least partially covers the ink image, and wherein the varnish composition prior to application comprises at least one latex emulsion, water, at least one base and at least one surfactant.
1. A recording medium with an ink image thereon, wherein a varnish at least partially covers the ink image, and wherein the varnish is applied to the recording medium as a varnish composition, wherein the varnish composition comprises at least one latex emulsion selected from the group consisting of styrene/acrylic emulsions, acrylic emulsions, polyester emulsions, and mixtures thereof, water, at least one base, at least one coalescing aid, at least one viscosity modifier comprising an acrylic alkali swellable emulsion or an associative thickener, and at least one surfactant, wherein the latex emulsion is from about 40 weight percent to about 95 weight percent of the varnish composition, the total amount of water is from about 30 weight percent to about 80 weight percent of the varnish composition, the coalescing aid is from about 1 weight percent to about 4 weight percent of the varnish composition, and the viscosity modifier is from about 0.1 weight percent to about 5 weight percent of the varnish composition.
2. The recording medium with an ink image thereon according to claim 1 , wherein the varnish composition further comprises at least one anti-foaming agent.
3. The recording medium with an ink image thereon according to claim 1 , wherein the at least one latex emulsion comprises a self-crosslinking and/or alkali soluble latex emulsion.
4. The recording medium with an ink image thereon according to claim 1 , wherein the at least one base is NaOH, ammonia, or an amino alcohol.
5. The recording medium with an ink image thereon according to claim 1 , wherein the at least one surfactant is an anionic surfactant, a nonionic surfactant, a silicone surfactant, a fluorosurfactant or mixtures thereof.
6. The recording medium with an ink image thereon according to claim 5 , wherein the anionic surfactant is selected from the group consisting of sulfosuccinates, disulfonates, phosphate esters, sulfates, sulfonates and mixtures thereof.
7. The recording medium with an ink image thereon according to claim 5 , wherein the fluorosurfactant is based on perfluorobutane sulfonates.
8. The recording medium with an ink image thereon according to claim 1 , wherein the nonionic surfactant is selected from the group consisting of polyvinyl alcohol, polyacrylic acid, methalose, methyl cellulose, ethyl cellulose, propyl cellulose, hydroxy ethyl cellulose, carboxy methyl cellulose, polyoxyethylene cetyl ether, polyoxyethylene lauryl ether, polyoxyethylene octyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene oleyl ether, polyoxyethylene sorbitan monolaurate, polyoxyethylene stearyl ether, poly oxyethylene nonylphenyl ether, dialkylphenoxy poly(ethyleneoxy) ethanol, isopropyl alcohol, acetylenic diols, octyl phenol ethoxylates, branched secondary ethoxylates, and mixtures thereof.
9. The recording medium with an ink image thereon according to claim 1 , wherein the at least one base is from about 1 weight percent to about 5 weight percent of the varnish composition, and the at least one surfactant is from about 0.01 weight percent to about 7.99 weight percent of the varnish composition.
10. The recording medium with an ink image thereon according to claim 1 , wherein a total glass transition temperature of the at least one latex emulsion is from about 30° C. to about 95° C.
11. The recording medium with an ink image thereon according to claim 1 , wherein the varnish composition has a surface tension from about 15 mN/m to about 40 mN/m.
12. The recording medium with an ink image thereon according to claim 1 , wherein the varnish composition has a viscosity from about 50 cP to about 750 cP at approximately room temperature.
13. The recording medium with an ink image thereon according to claim 1 , wherein the varnish composition as applied has a thickness of from about 2 μm to about 10 μm, and as dried has a thickness of from about 0.5 μm to about 5 μm.
14. The recording medium according to claim 1 , wherein the varnish composition covers the entire ink image.
15. The recording medium according to claim 1 , wherein the varnish composition is dried following application to form a varnish.
16. A varnish composition, consisting essentially of at least one latex emulsion selected from the group consisting of a styrene/acrylic emulsion, an acrylic emulsion, a polyester emulsion and mixtures thereof, water, at least one surfactant, at least one coalescing aid, at least one viscosity modifier comprising an acrylic alkali swellable emulsion or an associative thickener, and at least one base, wherein the at least one base is ammonia, and wherein the latex emulsion is from about 40 weight percent to about 95 weight percent of the varnish composition, the total amount of water is from about 30 weight percent to about 80 weight percent of the varnish composition, the coalescing aid is from about 1 weight percent to about 4 weight percent of the varnish composition, and the viscosity modifier is from about 0.1 weight percent to about 5 weight percent of the varnish composition.