VINYL ACRYLIC COPOLYMER EMULSION AND ITS USE IN STAIN-RESISTANT COATING COMPOSITIONS

Abstract

Vinyl acetate-acrylic copolymers, "vinyl acrylic," are provided in a water-based emulsion that can be used in architectural coatings to impart stain resistance. The vinyl acrylic copolymer particles in the emulsion may contain one or more particle size variations, each with a respective narrow particle size distribution. The vinyl acrylic copolymers contain an ethylenically unsaturated monomer as a comonomer and also contain a hydrolyzable silane comonomer. The hydrolyzable silane may be present as a comonomer in the vinyl acrylic copolymer and / or may be added to the vinyl acrylic copolymer emulsion in the form of a hydrolyzable silane that may have a reactive group capable of reacting with the vinyl acrylic copolymer.

Claims

NOVELTY OF THE INVENTION Having described the present invention, the following are considered novel and are therefore claimed as property: CLAIMS 1. An emulsion polymer composition characterized in that it comprises a population of polymer particle sizes, wherein the polymer particles comprise a copolymer comprising, in polymerized form: a) between 40 wt% and 95 wt%, based on the total weight of the polymer particles, of at least one monomer comprising vinyl acetate; b) between 1.0 wt% and 59.09 wt%, based on the total weight of the polymer particles, of at least one ethylenically unsaturated monomer; and c) between 0.01 wt% and 4.0 percent by weight, based on the total weight of the polymeric particles, of at least one monomer selected from free-radical polymerizable hydrolyzable silanes, wherein the at least one ethylenically unsaturated monomer b) is not selected from a) or c), wherein monomer a), monomer b), and monomer c) together total 100 percent by weight; and wherein the population of polymeric particle sizes comprises at least one modality, and wherein each modality comprises a respective weight-average particle size Dw¡ measured by disk centrifuge photosedimentometry and a respective number-average particle size Dn¡ measured by disk centrifuge photosedimentometry, and wherein for each modality, Dw¡ / Dn¡ is 2.0 or less.

2. The emulsion polymer composition according to claim 1, characterized in that the at least one ethylenically unsaturated monomer b) is selected from the group consisting of alkyl (meth) acrylate monomers, (meth) acrylamide monomers, and mixtures thereof.

3. The emulsion polymer composition according to claim 2, characterized in that the at least one ethylenically unsaturated monomer b) is selected from the group consisting of (meth) ethyl acrylate, butyl acrylate and mixtures thereof.

4. The emulsion polymer composition according to claim 1, characterized in that the copolymer further comprises, in polymerized form, at least one monomer selected from the group consisting of 2-acrylamido-2-methylpropane sulfonic acid (AMPS), sodium vinyl sulfonate (SVS), acrylic acid, methacrylic acid and mixtures thereof in an amount between 0.01 percent by weight and 2.5 percent by weight, based on the total dry weight of the polymer particles.

5. The emulsion polymer composition according to claim 1, IVI A / a / ZUZZ / UIIDII characterized in that the copolymer further comprises, in polymerized form, at least one monomer selected from the group consisting of vinyl versatate, vinyl esters of tertiary a-substituted carbon carboxylic acids, vinyl esters of C7-C20 carboxylic acids and mixtures thereof, in an amount between 0.4 percent by weight and 4 percent by weight, based on the total dry weight of the polymer particles.

6. The polymeric emulsion composition according to claim 1, characterized in that it comprises, in addition to 0.01 percent by weight to 1 percent by weight based on the total dry weight of the polymeric particles, hydroxyethylcellulose in copolymerized form.

7. A coating composition characterized in that it comprises an emulsion polymer composition according to claim 1 and at least one additional component dispersed in an aqueous medium.

8. The coating composition according to claim 7, characterized in that the at least one additional component comprises at least one pigment.

9. The coating composition according to claim 7, characterized in that it further comprises at least one additive selected from the group consisting of dispersants, surfactants, antifoaming agents, pH adjusters, extenders, opacifiers, rheology modifiers, coalescing agents, colorants, and mixtures thereof.

10. A method for coating a substrate, characterized in that the method comprises a step of applying a layer comprising the coating composition according to claims 7-9 onto a surface of the substrate and a step of drying the coating composition layer to obtain a film, wherein the film passes a cleanability test in at least one of MPI #143-148 and MPI #138-141.

11. An emulsion polymer composition characterized in that it comprises a population of polymer particle sizes, wherein the polymer particles comprise a copolymer comprising, in polymerized form: a) between 40 wt% and 95 wt%, based on the total weight of the polymer particles, of at least one monomer comprising vinyl acetate; and b) between 5 wt% and 60 wt%, based on the total weight of the polymer particles, of at least one ethylenically unsaturated monomer, wherein the at least one ethylenically unsaturated monomer b) is not selected from monomer a), wherein monomer a) and monomer b) together total 100 wt%;and wherein the polymer particle size population comprises at least one modality, and wherein each modality comprises a respective weight average particle size Dw¡ measured by disk centrifuge photosedimentometry and a respective number average particle size Dn¡ measured by disk centrifuge photosedimentometry and wherein for each modality, Dw¡ / Dn¡ is 2.0 or less; and wherein the polymer emulsion composition further comprises between 0.1 and 5 percent by weight, based on the total dry weight of the polymer particles, of at least one hydrolyzable silane selected from trialkoxysilanes, tetraalkoxysilanes and mixtures thereof.

12. The emulsion polymer composition according to claim 11, characterized in that the hydrolyzable silane is selected from epoxy-functionalized trialkoxysilanes.

13. The emulsion polymer composition according to claim 11, characterized in that the at least one ethylenically unsaturated monomer b) is selected from the group consisting of alkyl (meth) acrylate monomers, (meth) acrylamide monomers, and mixtures thereof.

14. The emulsion polymer composition according to claim 13, characterized in that the at least one ethylenically unsaturated monomer b) is selected from the group consisting of alkyl (meth) acrylate monomers, and mixtures thereof.

15. The emulsion polymer composition according to claim 14, characterized in that the at least one ethylenically unsaturated monomer b) is selected from the group consisting of (meth) ethyl acrylate, butyl acrylate, and mixtures thereof.

16. The emulsion polymer composition according to claim 11, characterized in that the copolymer further comprises, in polymerized form, between 0.01 percent by weight and 1.5 percent by weight, based on the total dry weight of the polymer particles, of at least one monomer selected from the group consisting of 2-achlamido-2-methylpropane sulfonic acid (AMPS), sodium vinyl sulfonate (SVS), acrylic acid, and methacrylic acid, and mixtures thereof.

17. The emulsion polymer composition according to claim 11, characterized in that the copolymer comprises, in polymerized form, between 0.4 percent by weight and 4 percent by weight, based on the total dry weight of the polymer particles, of a monomer selected from the group consisting of vinyl versatate, vinyl esters of tertiary a-substituted carbon carboxylic acids, vinyl esters of C7-C20 carboxylic acids, and mixtures thereof.

18. The emulsion polymer composition according to claim 11, characterized in that it further comprises from 0.01 wt% to 1 wt% based on the total dry weight of the polymer particles of a copolymerized colloidal stabilizer, selected from hydroxyethylcellulose. IVI A / a / ZUZZ / UII O II 19. A coating composition characterized in that it comprises an emulsion polymer composition according to claim 11 and at least one additional component dispersed in an aqueous medium.

20. The coating composition according to claim 19, characterized in that the at least one additional component comprises at least one pigment.

21. The coating composition according to claim 18, characterized in that it further comprises at least one additive selected from the group consisting of dispersants, surfactants, antifoaming agents, pH adjusters, extenders, opacifiers, rheology modifiers, coalescing agents, colorants and mixtures thereof.

22. A method for coating a substrate, characterized in that the method comprises a step of applying a layer comprising the coating composition according to claim 19 onto a surface of the substrate and a step of drying the coating composition layer to obtain a film, wherein the film passes a cleanability test in at least one of MPI #143-148 and MPI #138-141.