Method for tuning the gloss or color of a paint formulation

Abstract

The present invention relates to a method for preparing a plurality of containers of paint from a plurality of vessels containing separately an aqueous solution of rheology modifier, an aqueous dispersion of colorant, an aqueous dispersion of polymeric particles, and an aqueous dispersion of organic polymeric microspheres. In another embodiment, the present invention relates to a method of dispensing a colorant or opacifier or inorganic extender into separate containers that are partially filled with an aqueous pre-paint mixture of rheology modifier, polymeric particles, and organic polymeric microspheres. The method of the present invention provides a simple and cost effective way of preparing a variety of quantities of paint and finished paint at the point of sale.

Description

BACKGROUND

[0001] The present invention relates to a method of tuning the gloss of a paint formulation. The method of the present invention can be used to enable flexibility in the preparation of various paint formulations at the point of sale.

[0002] The public demand for different gloss and performance characteristics of paint requires retailers to maintain a large inventory of paint cans of various kinds and quantities. In response to these inventory pressures, retailers have attempted to develop point of sale models in which paint is produced at the store. However, commercial implementation of such models is difficult to achieve without the quality control and assurance provided by a trained formulator.

[0003] US 6,689,824 (Friel) discloses pre-coat pre-portioning of a tinting pigment, inorganic extender, and binder into a container to make a point of sale paint. However, the scope of the invention is limited to less complex road marking paint formulations which are only tinted to a limited range of colors, rather than tinted to a wide palette of colors for architectural paint formulations.

[0004] US 9,994,722 (Sheerin), in order to address the shortcomings of previous point of sale models, proposes starting with a paint that is completely prepared except for the tinting agent and gloss, and adjusting the gloss and color to more easily have a uniform color appearance of the paint at different glosses. Nonetheless, Sheerin’s solution does not address the inventory problem: multiple cans of paint are still required, and the only change in the final paint is the gloss and color. Furthermore, the solution does not address the need to change the tinting pigment (e.g., Ti02) or binder type (e.g., acrylics vs. styrene-acrylics vs. vinyl acetate) or binder concentration, or the need to adjust the viscosity in the final formulation, other than having more kinds of the initial completely prepared paint. Therefore, it would be advantageous in the field of point of sale paint preparation to develop a simple and universal method of preparing multiple paints at the point of sale that significantly reduces or even eliminates the need for inventory of paint containers. SUMMARY

[0005] The present invention addresses the needs in the art by providing a method comprising the steps of:

[0006] a) preparing a first paint by adding a tinting pigment, a tinting agent, or an inorganic extender to a first container, said first container being partially filled with a first aqueous pre-paint mixture of a rheology modifier, polymeric particles having a z-average particle size in the range of 50 nm to 600 nm, and organic polymeric microspheres having a median weight average (D 50 ) particle size in the range of 0.7 pm to 30 pm; and

[0007] b) preparing a second coating by adding the opacifying pigment, the colorant, or the inorganic extender to a second vessel that is partially filled with a second aqueous pre-coat mixture of the rheology modifier, the polymeric particles, and the organic polymeric microspheres;

[0008] wherein: i) the pigment volume concentration (PVC) of the organic microspheres in the first coating and the second coating is in the range of 5% PVC to 80% PVC, and the PVC of the first coating attributable to the organic microspheres differs from the PVC of the second coating attributable to the organic microspheres by at least 5 PVC units; and / or ii) the colorant in the first coating is different from the colorant in the second coating; provided that when a colorant is added to a vessel, sufficient rheology modifier is added to the vessel alone to produce a KU viscosity in the final coating in the range of 85 to 115 Krebbs units.

[0009] In a second aspect, the present invention is a method of tuning the gloss of a coating formulation at the point of sale, the method comprising the steps of:

[0010] a) preparing a first coating at the point of sale by dispensing into a first vessel, in any order or simultaneously:

[0011] i) an aqueous solution of a rheology modifier from a first vessel;

[0012] ii) an aqueous dispersion of a colorant from a second vessel;

[0013] iii) an aqueous dispersion of polymeric particles having a z-average particle size in the range of 50 nm to 600 nm from a third vessel; and

[0014] iv) an aqueous dispersion of organic polymeric microspheres having a median weight average (D 50 ) particle size in the range of 0.7 pm to 30 pm from a fourth vessel; and

[0015] b) preparing a second coating at the point of sale by dispensing into a second vessel the rheology modifier, the colorant, the polymeric particles, and the organic polymeric microspheres;

[0016] wherein: i) the pigment volume concentration (PVC) of the organic microspheres in the first coating and the second coating is in the range of 5% PVC to 80% PVC, and the PVC of the first coating attributable to the organic microspheres differs from the PVC of the second coating attributable to the organic microspheres by at least 5 PVC units; and / or ii) the colorant in the first coating is different from the colorant in the second coating.

[0017] The method of the present invention provides a simple and cost effective way of preparing various coatings at the point of sale. DETAILED DESCRIPTION

[0018] In a first aspect, the invention is a method comprising the steps of:

[0019] a) preparing a first coating by adding an opacifying pigment, a colorant, or an inorganic extender to a first vessel, the first vessel being partially filled with a first aqueous pre-coat mixture of a rheology modifier, polymeric particles having a z-average particle size in the range of 50 nm to 600 nm, and organic polymeric microspheres having a median weight average (D 50 ) particle size in the range of 0.7 pm to 30 pm; and

[0020] b) preparing a second coating by adding the opacifying pigment, the colorant, or the inorganic extender to a second vessel, the second vessel being partially filled with a second aqueous pre-coat mixture of the rheology modifier, the polymeric particles, and the organic polymeric microspheres;

[0021] wherein: i) the pigment volume concentration (PVC) of the organic microspheres in the first coating and the second coating is in the range of 5% PVC to 80% PVC, and the PVC of the first coating attributable to the organic microspheres differs from the PVC of the second coating attributable to the organic microspheres by at least 5 PVC units; and / or ii) the colorant in the first coating is different from the colorant in the second coating; with the proviso that when a colorant is added to a vessel, sufficient rheology modifier is added to the vessel alone to produce a KU viscosity in the final coating in the range of 85 to 115 Krebbs units.

[0022] Examples of suitable rheology modifiers in the pre-coat mixture include hydrophobically modified oxirane carbamate polymers (HEUR); hydrophobically modified alkali-swellable emulsions (HASE); alkali-swellable emulsions (ASE); and hydroxyethyl cellulose (HEC) and hydrophobically modified hydroxyethyl cellulose (HMHEC); and combinations thereof. If more than one rheology is desired, it is advantageous to use one or more additional vessels to independently control the amount of different rheology modifier. The amount of rheology modifier solution used in the pre-coat mixture can be readily predetermined to achieve the desired viscosity of the final uncolored coating.

[0023] The polymer particles (latex particles) in the pre-coat mixture have a z-average particle size by dynamic light scattering in the range of preferably 50 nm to 600 nm. Examples of suitable latex particles include acrylic, styrene-acrylic, urethane, alkyd resin, and vinyl ester (e.g., vinyl acetate and tertiary carbon vinyl versatate) latex particles, and combinations thereof. Acrylic and styrene-acrylic latex particles typically have a z-average particle size in the range of 70 nm to 300 nm, while vinyl ester latex particles typically have a z-average particle size in the range of 300 nm to 550 nm, as measured using dynamic light scattering. The pre-coat mixture can contain more than one type of latex particle.

[0024] Acrylic latex particles are preferably functionalized with methyl methacrylate and one or more acrylate ester functionalized selected from the group consisting of methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, and 2-propylheptyl acrylate. As used herein, the term “structural unit” of a specified monomer refers to the residue of the monomer after polymerization. For example, the structural unit of n-butyl acrylate is illustrated as follows:

[0025]

[0026] where the dashed line indicates the point of attachment of the structural unit to the polymer backbone.

[0027] Acrylic latex particles also preferably include structural units of acid monomers, including carboxylic acid, sulfuric acid, and phosphoric acid monomers, and salts thereof and combinations thereof. Examples of suitable carboxylic acid monomers include methacrylic acid, acrylic acid, and itaconic acid, and salts thereof; examples of suitable sulfuric acid monomers include methacrylate ethanesulfonate, methacrylate propanesulfonate, styrene sulfonic acid, vinyl sulfonic acid, and 2-acrylamido-2-methylpropanesulfonic acid, and salts thereof; examples of suitable phosphoric acid monomers include phosphonates and phosphonodihydroxides of alcohols, wherein the alcohol contains or is substituted with a polymerizable vinyl or alkenyl group. Preferred phosphonodihydroxides are phosphonates of hydroxyalkyl acrylate or methacrylate, including 2-phosphoethyl methacrylate (PEM), and salts thereof.

[0028] In one embodiment of the method of the present application, the acrylic latex particles are functionalized with a carboxylic acid monomer and a phosphoric acid monomer; in yet another embodiment, the acrylic latex particles include a shell having a PEM-functionalized core with protrusions. The acrylic latex particles can include a bimodal distribution of acrylic polymer particles having a shell with a PEM-functionalized core with protrusions and acrylic polymers without a protruding core. Such bimodal dispersions and their preparation are disclosed in US 9,920,194.

[0029] The median weight average particle size (D 50 ) of the organic polymeric microspheres is in the range of 0.7 pm, preferably 1 pm, and more preferably 2 pm, and most preferably 4 pm, to 30 pm, preferably to 20 pm, more preferably to 13 pm, and most preferably to 10 pm, as measured using a disc centrifuge photosedimentometer (DCP). g The organic polymeric microspheres are characterized by a non-film forming and preferably a crosslinked low T g core, i.e. a crosslinked core having a T g of not more than 25°C, more preferably not more than 15°C, and more preferably not more than 10°C, as calculated by the Fox equation. g The crosslinked core of the organic polymeric microspheres preferably comprises structural units of one or more monoethylenically unsaturated monomers, the homopolymer of which has a T g of not more than 20°C (low T g monomers), such as methyl acrylate, ethyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate. Preferably, the crosslinked low T g core comprises 50 wt.%, more preferably 70 wt.%, more preferably 80 wt.%, and most preferably 90 wt.%, to preferably 99 wt.%, and more preferably to 97.5 wt.%, based on the weight of the core, of structural units of low T g monoethylenically unsaturated monomers. N-butyl acrylate and 2-ethylhexyl acrylate are preferred low T g monoethylenically unsaturated monomers for preparing the low T g core.

[0030] The crosslinked core further comprises structural units of polyethylenically unsaturated monomers, examples of which include allyl methacrylate, allyl acrylate, divinyl benzene, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, butanediol (1,3) dimethacrylate, butanediol (1,3) diacrylate, ethylene glycol dimethacrylate, and ethylene glycol diacrylate. The concentration of structural units of polyethylenically unsaturated monomers in the crosslinked microspheres is preferably in the range of 1 wt.%, more preferably 2 wt.%, to 9 wt.%, more preferably to 8 wt.%, and most preferably to 6 wt.%, based on the weight of the core.

[0031] The crosslinked polymeric core is preferably coated with a high T g shell, i.e. a shell having a T g of at least 50°C, more preferably at least 70°C, and most preferably at least 90°C. The shell preferably comprises structural units of monomers, the homopolymer of which has a T g of more than 70°C (high T gmonomers), such as methyl methacrylate, styrene, isobornyl methacrylate, cyclohexyl methacrylate, and t-butyl methacrylate. High T g The shell preferably comprises at least 90 wt.% of structural units of methyl methacrylate.

[0033] The organic polymeric microspheres, preferably comprising a shell of high T g The shell is crosslinked low T g The microspheres of the core can further comprise 0.05% to 5% by weight of the microspheres of structural units of a polymerizable organophosphate represented by the structure of Formula I or a salt thereof:

[0034]

[0035] wherein R is H or CH3, wherein R 1 and R 2 are each independently H or CH3, provided that CR 2 CR 1 is not C(CH3)C(CH3); each R 3 is independently a linear or branched C2-C6 alkylene; m is 1 to 10; n is 0 to 5; provided that when m is 1, then n is 1 to 5; x is 1 or 2; and y is 1 or 2; and x+y=3.

[0036] When n is 0, x is 1 and y is 2, the polymerizable organophosphate or salt thereof is represented by the structure of Formula II:

[0037]

[0038] Preferably, each R 1 is H, and each R 2 is H or CH3; m is preferably 3, and more preferably 4; to preferably to 8, and more preferably to 7. Sipomer PAM-100, Sipomer PAM-200, and Sipomer PAM-600 phosphates are examples of commercially available compounds within the scope of Formula II compounds.

[0039] wherein n is 1; m is 1; R is CH3; R 1 and R 2 are each H; R 3 is -(CH2)5-; x is 1 or 2; y is 1 or 2, and x+y=3, the polymerizable organophosphate or salt thereof is represented by the structure of Formula III:

[0040]

[0041] A commercially available compound within the scope of Formula III is Kayamer PM-21 phosphate.

[0042] The organic polymeric microspheres can also include 0.05 wt% to 5 wt% of structural units of an oxirane salt of a bis-styryl phenol or a tris-styryl phenol represented by the structure of Formula IV based on the weight of the microspheres:

[0043]

[0044] where R 1 is H, CH2CR=CH2, CH=CHCH3, or 1-phenylethyl; R is C1-C4-alkyl; and n is 12 to 18. A commercial example of the structure of Formula IV is E-Sperse RS-1684 reactive surfactant.

[0045] The organic polymeric microspheres are distinct from the opacifying polymers, which include a water-containing core that forms a voided polymer particle after the dispersion is applied to a substrate and then evaporated.

[0046] In one aspect of the application, an opacifying pigment, colorant, or extender is added to the first and second containers. The opacifying pigment, colorant, or extender added to the second container can be, but is not necessarily, the same opacifying pigment, colorant, or extender added to the first container. In addition, a combination of pigments, colorants, and extenders can be added to the first and second containers.

[0047] Suitable opacifying pigments are inorganic opacifying pigments having a refractive index greater than 1.90, including Ti02and ZnO, with Ti02being preferred. The PVC of Ti02can be tuned to the desired brightness level. Other opacifying pigments include organic opacifying pigments, such as the opaque polymers, which can be used as a substitute or supplement to the inorganic pigments; if used as a supplement, the organic opacifying pigments are advantageously added to the paint container from a separate vessel. ROPAQUE™ hyper-opaque polymers and AQUACELL HIDE 6299 opaque polymers are commercial examples of the opaque polymers.

[0048] The colorant is a non-white colorant and can be organic or inorganic. Examples of organic colorants include phthalocyanine blue, phthalocyanine green, monoarylide yellow, diarylide yellow, benzimidazolone yellow, heterocyclic yellow, quinacridone magenta, quinacridone violet, organic reds (including both metalized and non-metalized azo reds). Inorganic colorants include carbon black, lamp black, iron oxide black, iron oxide yellow, iron oxide brown, and iron oxide red. In one aspect of the application, the coating prepared by the method of the application is a dark color coating, where the concentration of colorant ranges from 5 wt.%, preferably 8 wt.%, more preferably 10 wt.%, to 25 wt.%, more preferably to 20 wt.%, based on the weight of the coating. Dark color coatings contain substantially no opacifying pigments and inorganic extenders; that is, they contain less than 10 PVC, preferably less than 5 PVC, more preferably less than 1 PVC, and most preferably 0 PVC of any opacifying pigments and inorganic extenders.

[0049] When the colorant is added to the pre-coat mixture, sufficient rheology modifier is added from a separate container to maintain the KU viscosity in the range of 85 to 115 Krebs units.

[0050] Suitable inorganic extenders include talc, clay, mica, sericite, CaC03, nepheline syenite, feldspar, wollastonite, kaolinite, dicalcium phosphate, and diatomaceous earth. Although the method of the application allows for the addition of extenders, it is preferred to limit the addition of these extenders such that their PVC contribution is no more than 20 PVC, more preferably no more than 10 PVC, and most preferably no more than 5 PVC; further preferred is that the PVC contribution from inorganic extenders not exceed the PVC contribution of the microspheres. Inorganic extenders require labor-intensive and energy-intensive processes that include extraction and refinement from natural deposit sites into powders of widely varying particle size and shape. The high-density powders are then transported to coating manufacturing plants for further high-energy grinding to depolymerize the particles into useful primary particle sizes. The resulting inorganic extenders are high-surface area materials with different surface shapes and surface energies that require specialized formulation with binders, thickeners, and additives to overcome the quality control challenges inherent in the extraction-refinement-grinding process. Thus, reliance on inorganic extenders for the production of multiple coatings in a point-of-sale model, even a single gloss, creates logistical obstacles to the successful implementation of such a model.

[0051] In contrast, the polymeric organic microspheres in the pre-coat for the method of the application avoid the complexities associated with inorganic extenders. The polymeric microspheres can be readily prepared into uniform shapes with the desired size and surface energy, providing convenience and consistency to the coating manufacturing process.

[0052] The pre-coat mixture advantageously also contains one or more components such as defoamers, surfactants, biocides, coalescents, dispersants, other polymeric organic microspheres, and other latex particles.

[0053] Microspheres PVC is calculated according to the following formula:

[0054]

[0055] where binder refers to the contribution of the polymer from the aqueous dispersion of polymer particles that binds the pigment and extender particles together, and extender refers to the volume of non-opacifying extenders (including polymeric organic microspheres and inorganic extenders).

[0056] In one aspect of the application, the PVC of the organic microspheres differs by at least 5 PVC units between the second container. As used herein, "5 PVC units" refers to a difference in the percent contribution of the organic microspheres between the coatings; for example, a difference between 10% PVC and 15% PVC is a difference of 5 PVC units. It will be appreciated that the method of the application can be used to make any desired number of containers of coating and any desired PVC, provided that there is a difference of at least 5 PVC units between the pre-coating of the first container and the other pre-coating of at least one other container. Thus, making a second coating in a second container refers to making another container after making the coating in the first container, but not necessarily directly after making the coating in the first container.

[0057] Notably, the KU viscosity of the second coating can be readily tuned to be substantially the same as the KU viscosity of the first coating. More particularly, it is preferred that the difference in KU viscosity (ΔKU) between the pre-coating mixture before addition of the colorant and the final coating after addition of the colorant is less than 10 KU units, more preferably less than 5 KU units. It is further preferred that the first and second containers, and all other containers that can be used in the process of making the coatings at the point of sale, have a volume capacity of 0.25 to 5 gallons (0.95 L to 18.9 L).

[0058] In a second aspect, the rheology modifier, colorant, polymer particles, and organic polymeric microspheres are added from separate containers to make a first coating and a second coating. It is preferred in this second aspect that the coatings made are dark color coatings, whereby the addition of opacifying pigments and inorganic extenders is limited as described above. In this second aspect, the coatings differ in the pigment volume concentration contribution of the organic microspheres (by at least 5 PVC), or the nature of the colorant, or both.

[0059] The materials can be dispensed from the vessels into the containers in a variety of ways, including by means of a user interface and controller, as described in US 7,695,185 and US 6,969,190.

[0060] Example

[0061] Intermediate Example - Preparation of a dispersion of acrylic microspheres

[0062] Microspheres used in the examples and comparative examples (Intermediate 1) were prepared as described in US 2019 / 185687, Intermediate Example 2 [paragraph 0060] and adjusted to 43.5% solids. The particle size was 8.7 pm as measured by DCP as described in paragraph

[0063] of US 2019 / 185687.

[0063] Table 1 shows the comparative and example coating formulations and KU viscosity. Examples 1 and 2 were prepared by adding the ingredients to multiple containers, then sealing each container and mixing the contents using a vortex mixer for 3 min. The coatings of comparative examples 1 and 2 were mixed using an overhead stirrer. In each example, binder refers to EVOQUE TM 3390 all acrylic binder; defoamer refers to Byk-024 defoamer; RM1 refers to ACRYSOL TM RM-2020 NPR; and RM2 refers to ACRYSOL TM RM-8W. (EVOQUE and ACRYSOL are trademarks of The Dow Chemical Company or its affiliates.) Red refers to Colortrend 808 iron oxide red colorant; and blue refers to Colortrend 808 phthalocyanine blue colorant.

[0064] Table 1 shows the dark color coating formulations. The coatings of comparative examples 1 and 2 were blended using an overhead stirrer for 15 minutes and the coatings of examples 1 and 2 were blended using a vortex mixer for 3 minutes.

[0065] Table 1 - Coating Formulation

[0066]

[0067]

[0068] The comparative dark color coatings simulate adding colorant to fully formulated coatings at the point of sale. In this model, the coatings experience a significant drop in KU that cannot be further adjusted. On the other hand, the example dark color coatings containing all ingredients, including colorant and adjusted rheology modifier, produce coatings with constant and acceptable viscosity.

Claims

1. A method comprising the steps of: a) preparing a first coating by adding an opacifying pigment, a colorant or an inorganic extender to a first container, said first container being partially filled with a rheology modifier, polymeric particles having a z-average particle size in the range of 50 nm to 600 nm and a first aqueous pre-coating mixture of organic polymeric microspheres having a median weight average (D 50 ) particle size in the range of 0.7 μm to 30 μm; and b) preparing a second coating by adding the rheology modifier, the colorant, the polymeric particles, and the organic polymeric microspheres to a second container; wherein: i) the pigment volume concentration (PVC) of the organic microspheres in the first coating and the second coating is in the range of 5% PVC to 80% PVC, and the PVC attributable to the organic microspheres of the first coating differs from the PVC attributable to the organic microspheres of the second coating by at least 5 PVC units; and / or ii) the colorant in the first coating is different from the colorant in the second coating; provided that when a colorant is added to a container, sufficient rheology modifier is added to the container alone to produce a KU viscosity in the final coating in the range of 85 to 115 Krebbs units.

2. The method of claim 1, wherein a colorant is added to the first container and the second container, and sufficient rheology modifier is added to each of the first container and the second container to produce a KU viscosity in the final coating in the range of 85 to 115 Krebbs units.

3. The method of claim 2, wherein the colorant is added at a sufficient level to achieve a concentration of 5 wt% to 25 wt% in each of the first coating and the second coating.

4. The method of claim 3, wherein the pigment volume concentration of opacifying pigments and inorganic extenders in the coating is less than 5 PVC.

5. The method of claim 2, wherein the first coating and the second coating have a difference in pigment volume concentration attributable to the organic microspheres of at least 5 PVC units.

6. The method of claim 2, wherein the colorant in the first coating is different from the colorant in the second coating.

7. The method of claim 2, wherein the difference in KU viscosity between the aqueous pre-coat mixture and the coating is less than 10 Krebbs units.

8. The method of claim 7, wherein the difference in KU viscosity between the aqueous pre-coat mixture and the coating is less than 5 Krebbs units.

9. A method comprising the steps of: a) preparing a first coating at the point of sale by dispensing into a first container, in any order or simultaneously: i) an aqueous solution of a rheology modifier from a first vessel; ii) an aqueous dispersion of a colorant from a second vessel; iii) an aqueous dispersion of polymeric particles having a z-average particle size in the range of 50 nm to 600 nm from a third vessel; and iv) a median weight average (D 50 ) an aqueous dispersion of organic polymeric microspheres having a particle size in the range of 0.7 μm to 30 μm; and b) preparing a second coating at the point of sale by dispensing into a second container: i) the rheology modifier; ii) the colorant; iii) the polymeric particles; and iv) the organic polymeric microspheres. wherein: i) the pigment volume concentration (PVC) of the organic microspheres in the first coating and the second coating is in the range of 5% PVC to 80% PVC, and the PVC of the first coating attributable to the organic microspheres differs from the PVC of the second coating attributable to the organic microspheres by at least 5 PVC units; and / or ii) the colorant in the first coating is different from the colorant in the second coating.

10. The method of claim 9, wherein the PVC of the organic microspheres in the first coating and the second coating is in the range of 5% PVC to 80% PVC, and the PVC of the first coating attributable to the organic microspheres differs from the PVC of the second coating attributable to the organic microspheres by at least 5 PVC units.

11. The method of claim 9, wherein the colorant in the first coating is different from the colorant in the second coating.

Images