Coating compositions and methods for blocking tannin migration

Abstract

A tannin blocking coating is provided. The coating includes a binder resin and casein. The tannin blocking coating mitigates migration of tannin from a substrate on which the tannin blocking coating is placed.

Description

Cross-reference to related applications

[0001] This application relates to and claims priority to U.S. Provisional Application Serial No. 63 / 566,950, filed March 19, 2024, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0002] This invention relates to a tannin-blocking coating and its preparation method. The tannin-blocking coating contains a sufficient amount of tannin-blocking components to reduce the migration of tannins from a substrate on which the tannin-blocking coating is placed. Background Technology

[0003] Coatings are applied to a substrate to protect it and also to achieve a desired appearance, including color and gloss. Specific coatings can be selected based on the material of the substrate. For example, wood coatings can be formulated with specific viscosities and opacities suitable for covering different textures and colors of wood. Wood substrates with high tannin content (such as pine or cedar) can be particularly difficult to coat because tannins migrate from the wood and into the overcoating. These tannins can seep through several layers of coating onto the wood substrate, resulting in a coating with a brownish hue. Oil-based coatings, binder resins, and / or additives have been used to mitigate tannin migration, but these systems limit the other additives and / or resins that can be used in formulations, thus limiting the overall properties of the coating. Summary of the Invention

[0004] One object of the present invention is to provide a tannin-blocking coating containing a sufficient amount of casein to mitigate the migration of tannins from a substrate on which the tannin-blocking coating is applied.

[0005] Another object of the present invention is to provide a coating system for a substrate comprising at least one layer of tannin-blocking coating, wherein the tannin-blocking coating contains more tannin than the overcoating.

[0006] Another object of the present invention is to provide a method for applying a tannin-blocking coating to a substrate.

[0007] These and other objects of the present invention (alone or in combination) have been achieved by discovering a tannin-blocking coating comprising an adhesive resin and casein, wherein the amount of casein in the tannin-blocking coating is sufficient to receive tannins migrating from the substrate upon drying and substantially prevents tannins from migrating out of the tannin-blocking coating after drying. The tannin-blocking coating and its application method will be further described in the following detailed description and the appended claims. Attached Figure Description

[0008] The present invention may take the physical form of certain parts and arrangements of parts, the preferred embodiments of which will be described in detail in the specification and shown in the accompanying drawings which form part of the specification, and wherein:

[0009] Figure 1 An exemplary chemical structure of casein in tannin-blocking coatings that can be used for further discussion herein is shown.

[0010] Figure 2 Cross-sectional views are shown of some embodiments of a coating system disposed on a substrate and comprising tannin-blocking coatings as will be discussed further herein.

[0011] Figure 3 , Figure 4 , Figure 5 , Figure 6 and Figure 7 Cross-sectional views are shown of some embodiments of a method for applying a coating system to a substrate such that tannins from the substrate are substantially contained within a tannin-blocking coating on the substrate.

[0012] Figure 8 It shows that it can be used with Figures 3 to 7 The flowcharts show some implementation schemes of the methods shown. Detailed Implementation

[0013] The range of values ​​expressed using endpoints includes all values ​​contained within that range (for example, 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.).

[0014] As used in this application, the terms “comprising,” “having,” “with,” or variations thereof are intended to be inclusive in a manner similar to the term “comprising.” The singular forms “a,” “an,” and “the,” “the,” “the,” “at least one,” and “one or more” are used interchangeably. Thus, for example, a coating composition containing “one” additive means that the coating composition may contain “one or more” additives.

[0015] As used throughout this specification and claims, approximate language can be applied to modify quantitative representations that can be permissibly varied without causing a change in the essential function associated with them. Therefore, values ​​modified by terms such as “about” are not limited to the specified precise values. In some cases, approximate language may correspond to the precision of the instrument used to measure the value. Furthermore, unless otherwise specifically stated, the use of terms such as “first,” “second,” etc., does not indicate order or importance, but rather serves to distinguish one element from another.

[0016] The term "comprising" and its variations are not intended to be limiting when they appear in the specification and claims.

[0017] As used herein, the terms “may” and “may” indicate a possibility of occurring within a set of circumstances; possessing the specified property, characteristic, or function; and / or defining one verb by expressing one or more of the properties, capabilities, or possibilities associated with the verb being defined. Thus, the use of “may” and “may” indicates that the modified term is clearly appropriate, capable, or suitable for the indicated capability, function, or use, while taking into account that in some cases the modified term may sometimes be inappropriate, incapable, or unsuitable. For example, in some cases an event or capability may be anticipated, while in others it may not occur—this distinction is captured by the terms “may” and “may”.

[0018] As used herein, the term "acrylic acid" includes (meth)acrylic acid, (meth)alkyl acrylates, (meth)acrylamide, (meth)acrylonitrile, and their modified forms, such as (meth)hydroxyalkyl acrylates. Throughout this document, the phrase "(meth)acryloyl" refers to both "methacryloyl" and "acryloyl". For example, (meth)acrylic acid refers to both methacrylic acid and acrylic acid, and methyl methacrylate refers to both methyl methacrylate and methyl acrylate.

[0019] When the term "aliphatic" is used in the context of carbon-carbon double bonds, it includes straight-chain (or open-chain) aliphatic carbon-carbon double bonds and cyclic aliphatic carbon-carbon double bonds, but excludes aromatic carbon-carbon double bonds of aromatic rings.

[0020] The term "aqueous composition" or dispersion as used herein means particles dispersed in an aqueous medium. An "aqueous medium" as used herein refers to a continuous phase comprising at least 50% by weight of water, wherein the remaining composition of the aqueous medium comprises particles and water-miscible compounds, such as, for example, alcohols, glycols, glycol ethers, glycol esters, etc.

[0021] Unless otherwise specified, the term “(co)polymer” as used herein includes both homopolymers (polymers containing units derived from a single monomer) and copolymers (polymers containing units derived from two or more different monomers).

[0022] As used herein, the term "crosslinking agent" refers to a molecule capable of forming covalent bonds between polymers or between two different regions of the same polymer.

[0023] When used in the context of coatings applied to a substrate, the term "on" includes both coatings applied directly or indirectly to the substrate. Thus, for example, a coating applied to a primer layer covering a substrate constitutes a coating applied to the substrate.

[0024] The terms "preferred" and "ideally" refer to embodiments of the invention that provide certain beneficial effects in certain circumstances. However, other embodiments may also be preferred in the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are unavailable, and is not intended to exclude other embodiments from the scope of the invention.

[0025] As used in this article, the term “structural unit” (also known as a polymeric unit) for naming monomers refers to the residue of the monomer after polymerization, or the monomer in its polymerized form.

[0026] According to an embodiment of the present invention, a tannin-blocking coating is provided. The tannin-blocking coating comprises a binder resin and casein. The tannin-blocking coating mitigates the migration of tannins from a substrate on which the tannin-blocking coating is applied.

[0027] According to another embodiment of the present invention, a coating system is provided. The coating system includes a substrate, a first coating disposed on the substrate, and a second coating disposed on the first coating. The first coating comprises an adhesive resin and casein. The first coating mitigates migration from the substrate to the second coating.

[0028] According to yet another embodiment of the present invention, a method for coating a substrate is provided. The method includes applying a first coating to the substrate and applying a second coating to the first coating. The first coating comprises an adhesive resin and casein. The first coating mitigates the migration of tannins from the substrate to the second coating.

[0029] The embodiments of the invention disclosed herein relate to a tannin-blocking coating. This tannin-blocking coating comprises a binder resin and casein. When the tannin-blocking coating is applied to a tannin-containing substrate, tannins may migrate from the substrate into the tannin-blocking coating. The casein then interacts with the tannins such that the total molecular weight of the tannins and casein is high enough to limit further tannin migration. In some embodiments, the casein binds to the tannins to effectively complex and isolate them via hydrogen bonds, van der Waals forces, and molecular entanglement. After the tannin-blocking coating dries, a second coating may be applied to it. The tannins in the tannin-blocking coating can retain and restrict the casein adhering to and within the coating, such that substantially no tannin migration occurs into the second coating. "Substantially no tannins" or "substantially tannin-free" means that if any tannins do migrate into the second coating, the color of the second coating will not be affected (or will not be significantly altered) by such a small amount of tannin that has migrated therein.

[0030] Casein is a phosphoprotein with a high proline amino acid content. Several casein structures can be found naturally in milk or synthesized. Figure 1 An example of a general casein chemical structure is shown. Tannin-blocking coatings described herein can contain caseins, all of which may have the same or different chemical structures. In milk, casein acts as an emulsifier. Therefore, in the tannin-blocking coatings described herein, casein can be readily mixed with a variety of binder resins without causing gelation. Additionally, casein is nonionic, which also increases its compatibility with a variety of binder resins compared to other known tannin-blocking mechanisms. Casein will remain nonionic as long as the pH when mixed with the binder resin remains above its isoelectric point. The binder resin can be anionic, cationic, or nonionic. In some embodiments, the binder resin is preferably acidic to facilitate the blocking of tannins, which are also acidic. Furthermore, as demonstrated by the presence of casein in milk containing a large amount of water, casein can be used in water-based coating systems. Therefore, the binder resin can be aqueous, solvent-based, or a mixture thereof (e.g., aqueous). Tannin-blocking coatings can contain a variety of binder resins. Casein can be added to any aqueous or solvent-based resin system to provide tannin blocking action. Non-limiting examples of one or more adhesive resins in tannin-blocking coatings include acrylic resins (e.g., poly(meth)acrylic), latex resins, polyester resins, polyethylene resins, polyisocyanate resins, alkyd resins, amino resins, epoxy resins, polyurethane resins, polyester resins, silicone-based resins, alkali-soluble resins, and combinations thereof.

[0031] In some embodiments, casein is present in an amount of about 0.1% to about 25% by weight, more preferably about 0.1% to about 20% by weight, even more preferably about 0.5% to about 15% by weight, or even more preferably about 0.5% to about 10% by weight of the total tannin-blocking coating, while the remainder of the tannin-blocking coating comprises binder resins and other additives. The amount of casein can also be formulated for a specific substrate. For example, cedar wood has a high amount of tannins. Therefore, tannin-blocking coatings for cedar wood can have a higher amount of casein than coatings formulated for other wood species. Tannin-blocking coatings can be applied to natural wood, engineered wood, wood composites, fiber cement boards, metals, plastics, ceramics, or combinations thereof. Thus, although tannin-blocking coatings are partially formulated to block tannin migration, they can still be applied to tannin-free substrates.

[0032] The amount of casein in a tannin-blocking coating can alter the overall rheological properties of the coating, for example, by increasing the coating viscosity primarily in the medium and high shear range. The amount of casein in a tannin-blocking coating is typically low enough that this change in rheology does not limit the application of the tannin-blocking coating (e.g., by roller coating, brush coating, spray coating, etc.). In some embodiments, the tannin-blocking coating may contain rheology modifiers to counteract any undesirable rheological changes from casein and / or to achieve specific rheological properties for the application method. For example, in some embodiments, the tannin-blocking coating contains no more than about 10% by weight of casein to maintain the application flexibility of the tannin-blocking coating. The desired viscosity of the tannin-blocking coating before application to the substrate may be, for example, between 200 centipoise and 1500 centipoise at 77 degrees Celsius, as measured according to ASTM D2196-86. Viscosity measurements can also be performed according to some other suitable viscosity testing methods.

[0033] In some embodiments, the coating may contain a small amount of casein, taking into account the amount of tannin in the tannin-containing substrate to which the tannin-blocking coating is applied. In some such embodiments, several layers of tannin-blocking coating may be applied to the tannin-containing substrate, some of which may migrate between each layer of tannin-blocking coating. When each tannin-blocking coating is applied to the substrate, the available casein coagulates with any residual migrating tannin, such that the several layers of tannin-blocking coating together can prevent tannin migration into any topcoat on which it is applied.

[0034] In addition to casein and adhesive resins, tannin-blocking coatings may contain cationic resins or other additives to enhance the tannin-blocking ability of the coating. For example, in some embodiments, tannin-blocking coatings may also contain additional tannin-blocking additives, such as polyvinylpyrrolidone, zinc oxide, etc. Furthermore, in some embodiments, tannin-blocking coatings are used as a primer layer applied directly to a substrate. Therefore, tannin-blocking coatings may contain additives adapted to facilitate adhesion of the tannin-blocking coating to the substrate and / or facilitate adhesion between the tannin-blocking coating and the coating layer formed thereon. Other additives in tannin-blocking coatings may include, for example, pigments, fillers, diluents, extenders, wetting agents, leveling agents, dispersants, anti-settling agents, defoamers, rheology modifiers, etc., to achieve desired properties such as viscosity, wettability, curing speed, adhesion, aesthetics, film thickness, etc. Each optional component is preferably contained in a sufficient amount to achieve its intended purpose, but not in an amount that adversely affects the quality of the resulting tannin-blocking coating, such amounts are generally understood by those skilled in the art.

[0035] Additionally, non-limiting examples of organic solvents suitable for use in water-based and / or solvent-based coating compositions of the present invention include aliphatic hydrocarbons (e.g., mineral oil, kerosene, VM&P naphtha solvent, etc.); aromatic hydrocarbons (e.g., benzene, toluene, xylene, naphtha solvents 100, 150, 200 series products, etc.); alcohols (e.g., ethanol, n-propanol, isopropanol, n-butanol, isobutanol, etc.); ketones (e.g., acetone, 2-butanone, cyclohexanone, methyl aryl ketone, ethyl aryl ketone, methyl isopentyl ketone, etc.); esters (e.g., ethyl acetate, butyl acetate, etc.); glycols (e.g., butyl ethylene glycol); glycol ethers (e.g., ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, etc.); glycol ether esters (e.g., butyl ethylene glycol acetate, methoxypropyl acetate, etc.); and mixtures thereof.

[0036] It should be understood that other embodiments of the present invention relate to a tannin-blocking caulking agent or tannin-blocking sealant. The tannin-blocking caulking agent or sealant may contain casein and an adhesive resin suitable for use as a caulking agent or sealant. Compared to tannin-blocking coatings, tannin-blocking caulking agents or sealants may have higher viscosity, greater thickness, and / or contain different additives. In some embodiments, the tannin-blocking caulking agent or sealant may be used in combination with tannin-blocking coatings to enhance the tannin-blocking effect. For example, a tannin-blocking caulking agent can be used to bond two pieces of wood (or some other substrate) together. The wood substrate and the tannin-blocking caulking agent can then be coated with a tannin-blocking coating. After applying one or more layers of tannin-blocking caulking agent and / or coating, a topcoat can be applied to the wood substrate. Because both the tannin-blocking caulking agent and the tannin-blocking coating contain casein, virtually no tannin migrates to the topcoat.

[0037] Now go to Figure 2 This document will describe some embodiments of system 100 comprising various coatings. System 100 may include a tannin-blocking coating 104 disposed on a substrate 102. The tannin-blocking coating 104 may serve as a primer layer on the substrate 102. Thus, the tannin-blocking coating 104 may be in direct contact with the substrate 102, or may be spaced apart from the substrate 102 by an intermediate additional coating. In some embodiments, the substrate 102 is a tannin-containing substrate, such as wood. The tannin-blocking coating 104 may contain a self-leveling agent to fill any uneven areas on the substrate 102, such as wood grain, while also providing a substantially smooth tannin-blocking coating 104 on the substrate 102. A second coating 106 is disposed on the tannin-blocking coating 104. As will be discussed further herein, the casein-containing tannin-blocking coating 104 may receive tannins from the substrate 102, but also substantially prevents further migration of tannins into the second coating 106 covering the tannin-blocking coating 104.

[0038] In some embodiments, several layers of tannin-blocking coating 104 may be applied to substrate 102. When dry, each layer of tannin-blocking coating 104 may have a dry film thickness in, for example, preferably between 3 micrometers and 260 micrometers, more preferably between 5 micrometers and 30 micrometers, and most preferably between 10 micrometers and 20 micrometers. When substrate 102 contains a high amount of tannin, a higher dry film thickness of tannin-blocking coating 104 may be desired to increase the amount of casein available for coagulation with any mobile tannins migrating from substrate 102. In some embodiments, several layers of tannin-blocking coating 104 may be used to increase the amount of casein available for coagulation with any mobile tannins migrating from substrate 102. In some embodiments, the aforementioned values ​​for the dry film thickness of each layer of tannin-blocking coating 104 are the dry film thickness before sanding. In some embodiments, each layer of tannin-blocking coating 104 is sanded after drying and before applying another coating. In other embodiments, sanding of each layer of the tannin-blocking coating 104 is omitted, at least because sanding reduces the dry film thickness and, consequently, the amount of casein available in the tannin-blocking coating 104. Therefore, if sanding were performed on each layer of the tannin-blocking coating 104, the number of layers of the tannin-blocking coating 104 could be increased to account for the loss of dry film thickness caused by sanding.

[0039] Figures 3 to 7 Some embodiments of the method for applying the tannin-blocking coating described herein to a substrate are shown.

[0040] like Figure 3As shown, a substrate 102 is provided. In some embodiments, the substrate 102 may include a tannin-containing material or a tannin-free material. As an example, the substrate 102 contains tannin 302, which, for illustrative purposes... Figure 3 As shown in the diagram. It should be understood that although tannin 302 provides a yellowish-brown color to the substrate 102 or the coating, tannin 302 is not discernible to the human eye on its own, as it penetrates through the skin. Figures 3 to 7 As shown. Tannin 302 may be evenly distributed throughout the substrate 102, or it may be more concentrated in certain areas than in others. For example, in some wood-based substrates, tannin 302 is particularly concentrated in the grain or knots.

[0041] like Figure 4 As shown, a new layer 404 of tannin-blocking coating is applied to substrate 102. The new layer 404 can be applied by brushing, rolling, spraying, or some other suitable application technique. Figure 4 The substrate 102 and the tannin-blocking coating fresh layer 404 are shown shortly after the application of the fresh layer 404.

[0042] like Figure 5 As shown, after a period of time from the initial application of the tannin-blocking coating, tannin 302 begins to migrate 502 out of the substrate 102 and into the partially dried layer 504 of the tannin-blocking coating. As tannin 302 migrates 502 into the partially dried layer 504, casein suspended throughout the partially dried layer 504 adheres to the migrating tannin 302. Over time, the migration 502 of tannin 302 within the partially dried layer 504 slows down, and eventually the tannin 302 becomes essentially immobile.

[0043] like Figure 6 As shown, the tannin-blocking coating 104 dries and traps tannin 302. The tannin-blocking coating 104 can be dried or cured under specific conditions of the adhesive resin based on the tannin-blocking coating 104. For example, the tannin-blocking coating 104 can be dried as follows: at room temperature or at elevated temperatures; in the presence of moisture; when exposed to UV light; or under some other drying or curing mechanisms suitable for the adhesive resin. Just as the tannin-blocking coating 104 is applied (e.g., Figure 4 Tannin-blocking coating 104 contains a first amount of tannin 302 (e.g., substantially no tannin); applied after the tannin-blocking coating 104 but before the tannin-blocking coating 104 dries (e.g., Figure 5 Tannin-blocking coating 104 contains a second amount of tannin 302 greater than the first amount; and once the tannin-blocking coating 104 dries (e.g., Figure 6The tannin-blocking coating 104 contains a third amount of tannin 302, greater than the second amount. Similarly, after the application of the tannin-blocking coating 104, the amount of tannin 302 in the substrate 102 may decrease over time as tannin 302 migrates from the substrate 102 and into the tannin-blocking coating 104. During drying, tannin 302 can be trapped within the tannin-blocking coating 104 because the coagulated casein and tannin 302 become too large to migrate through the tannin-blocking coating 104. Although tannin 302 alone is indistinguishable, the dried tannin-blocking coating 104 may exhibit a yellowish-brown hue that was not present before coating the substrate 102.

[0044] like Figure 7 As shown, the second coating 106 is formed on the tannin-blocking coating 104. The casein in the tannin-blocking coating 104 substantially prevents tannin 302 from migrating out of the tannin-blocking coating 104 and into the second coating 106. Therefore, due to the intervening tannin-blocking coating 104, the pigment in the second coating 106 is unaffected or substantially unaffected by tannin 302 from the underlying substrate 102. Thus, the second coating 106 is substantially tannin-free. It should be understood that several other layers comprising compositions identical or different from those of the tannin-blocking coating 104 and the second coating 106 may be formed on the substrate 102 to achieve the desired properties of the entire coating system 100.

[0045] Figure 8 A flowchart 800 illustrates some embodiments of a method for applying a tannin-blocking coating containing casein to a tannin-containing substrate. In some embodiments, Figure 8 The steps in flowchart 800 correspond to Figures 3 to 7 The method shown.

[0046] In step 802, a casein-containing coating is applied to a tannin-containing substrate.

[0047] In step 804, the casein-containing coating is dried.

[0048] At step 806, a second coating is applied over the casein-containing coating, wherein the casein-containing coating mitigates the migration of tannins from the substrate to the second coating.

[0049] The following embodiments are provided to illustrate the present invention and its advantages, but should not be construed as limiting the scope of the invention.

[0050] As discussed above, tannin-blocking coatings are configured to receive tannins migrating from the substrate. Therefore, the color of the tannin-blocking coating may vary between application and drying times. When a second coating is applied over the tannin-blocking coating, casein is designed to prevent tannin migration into the second coating. Therefore, when the disclosed tannin-blocking coating is applied to a tannin-containing substrate prior to the second coating, the color change of the second coating over time should be less than the color change without the tannin-blocking coating. Even if tannins do not migrate into the second coating, some color changes in the second coating may still occur naturally over time due to other known causes, such as moisture, light, and other environmental factors.

[0051] Color changes in a coating can be measured using a spectrophotometer, which measures the absorption and intensity of light when directed onto a substrate. In the coatings industry, data collected from a spectrophotometer over time can be used to illustrate color changes in the coating on a substrate. A spectrophotometer can measure the coating's luminance (based on the amount of white light reflected from the coating); the amount of red-green in the coating; the amount of yellow-blue in the coating; and the amount of all colors in the coating. When measuring color changes in a coating over time, spectrophotometer data can be collected at a first time point and a second time point. The data at the first time point are compared with the data at the second time point and are typically reported as changes in luminance (ΔL) and changes in hue and chromaticity (ΔC). Color data changes between the first and second time points can also be expressed as changes in red-green (ΔC(RG)) and changes in yellow-blue (ΔC(YB)). As discussed in ASTM D2244, the total color difference (ΔE) can be calculated based on the ΔL, ΔC(RG), ΔC(YB), and ΔC values.

[0052] As an example, Table 1 presents the color changes of a second coating applied to a tannin-containing substrate and shows that the tannin-blocking coating does indeed mitigate the color changes of the coating in which it forms. Control A has no tannin-blocking layer between the second coating and the tannin-containing substrate. Samples 1 and 2 comprise the disclosed casein-containing tannin-blocking coating between the second coating and the tannin-containing substrate. The casein-containing tannin-blocking coatings in Samples 1 and 2 contain casein in a latex-based adhesive resin. Sample 2 contains a higher percentage by weight of casein than Sample 1. Control B contains a commercially available tannin-blocking coating between the tannin-containing substrate and the second coating. The commercially available tannin-blocking coating is latex-based and contains known tannin-blocking additives and / or resins, but does not contain any casein. Sample 3 comprises the disclosed casein-containing tannin-blocking coating between the second coating and the tannin-containing substrate. The casein-containing tannin-blocking coating in Sample 3 contains casein added to a commercially available tannin-blocking coating.

[0053]

[0054] Each sample panel in Table 1 was prepared and tested according to the same test procedure. It should be understood that the following test procedure is merely an example and other time, temperature, and environmental conditions may be used. To collect the data in Table 1, a suitable tannin-blocking coating was first brushed onto the mahogany substrates of Sample 1, Sample 2, Sample 3, and Control B. The mahogany substrate of Control A remained untreated. Each sample panel was then air-dried at ambient temperature for 7 days. Each sample panel was then coated with a commercially available satin varnish as a second coating. The samples were again air-dried at ambient temperature for 7 days. After these 7 days of drying of the second coating, each sample panel was measured at a spectrophotometer to collect initial color measurements. In some embodiments, the spectrophotometer may collect data at different incident angles, such as gloss (60) and gloss (85). After collecting the initial readings for each sample panel, the sample panels were placed in a humidity chamber set at approximately 95℉ and approximately 80% to approximately 90% relative humidity for 14 days. Such high temperature and humidity conditions are used to allow any mobile tannins to migrate into the second coating. After 14 days in a humidity chamber, each sample plate was air-dried at ambient temperature for 7 days. Then, each sample plate was measured again using a spectrophotometer to collect the final color measurements. The final color measurements were compared with the initial color measurements to calculate the values ​​of ΔL, ΔC(RG), ΔC(YB), ΔE, and ΔC.

[0055] Since no tannin-blocking layer was present, Control A had the highest ΔL, ΔC(RG), ΔC(YB), ΔE, and ΔC values, indicating that Control A exhibited the greatest color change. Therefore, in Table 1, each spectrophotometer value measured in Control A was normalized to 100%, such that "100%" indicates the maximum color change. The spectrophotometer measurements of each of Sample 1, Sample 2, Sample 3, and Control B were divided by each spectrophotometer measurement of Control A and expressed as a percentage. For example, the ΔL of Sample 1 was 4% lower than that of Control A. Table 1 shows that Samples 1 and 2, which included a tannin-blocking layer containing casein in the latex-based adhesive resin, did indeed reduce the amount of color change in the second coating. The slight variation in color change values ​​between Sample 1 and Sample 2 indicates that, in some embodiments, increasing the amount of casein in the tannin-blocking coating did not significantly affect the color change effect of the tannin-blocking coating. In some embodiments, when the tannin-blocking coating contains more than 1% by weight or more preferably more than 0.5% by weight of casein, the tannin-blocking properties and color change properties of the tannin-blocking coating are not significantly changed. Furthermore, when comparing Control B with Sample 3, Table 1 shows that the addition of casein to commercially available tannin-blocking coatings further reduced color change in the second coating.

[0056] In some embodiments, Sample 1, Sample 2, and Sample 3 have ΔE values ​​less than 10, more preferably less than 6.5, and even more preferably less than 3.5. Furthermore, in some embodiments, Sample 1, Sample 2, and Sample 3 have ΔC(RG) values ​​less than 3.5 and more preferably less than 3. In some embodiments, Sample 1, Sample 2, and Sample 3 have ΔC(YB) values ​​less than 3, more preferably less than 2.5, and even more preferably less than 1.5. In some embodiments, Sample 1, Sample 2, and Sample 3 have ΔC values ​​less than 4.5, more preferably less than 4, and even more preferably less than 2.5. In some embodiments, Sample 1, Sample 2, and Sample 3 have ΔL values ​​in the range of about -4.9 to about -2. Each of these spectrophotometric values ​​indicates that the casein-containing tannin-blocking coating mitigates color changes in the overcoat.

[0057] The following are some non-limiting examples of embodiments of the present invention:

[0058] Implementation Scheme 1. A tannin-blocking coating, the tannin-blocking coating comprising: Adhesive resin; and Casein, Tannin-blocking coatings reduce the migration of tannins from the substrate on which the tannin-blocking coating is applied.

[0059] Implementation Scheme 2. The tannin-blocking coating according to Implementation Scheme 1, wherein the amount of casein in the tannin-blocking coating is sufficient to receive tannins migrating from the substrate during drying and substantially prevent tannins from migrating out of the tannin-blocking coating after drying.

[0060] Implementation Scheme 3. The tannin-blocking coating according to Implementation Scheme 1 or Implementation Scheme 2, wherein casein is present in the tannin-blocking coating in an amount of about 0.5% to about 10% of the total amount of the tannin-blocking coating.

[0061] Implementation Scheme 4. The tannin-blocking coating according to any one of Implementation Schemes 1 to 3, wherein the adhesive resin is water-based.

[0062] Implementation Scheme 5. The tannin-blocking coating according to any one of Implementation Schemes 1 to 4, wherein the adhesive resin is a resin containing silicon-based groups.

[0063] Implementation Scheme 6. The tannin-blocking coating according to any one of Implementation Schemes 1 to 5, wherein the adhesive resin comprises an alkali-soluble resin.

[0064] Implementation Scheme 7. A tannin-blocking coating according to any one of Implementation Schemes 1 to 6, wherein the adhesive resin is acidic.

[0065] Implementation Scheme 8. A tannin-blocking coating according to any one of Implementation Schemes 1 to 7, wherein the adhesive resin is cationic.

[0066] Implementation Scheme 9. The tannin-blocking coating according to any one of Implementation Schemes 1 to 8, wherein the adhesive resin is a member selected from the group consisting of: poly(meth)acrylic acids, epoxy resins, polyesters, polyethylene esters, alkyd resins, polyurethanes, polyisocyanates, amino resins, latexes, and silicone-based resins.

[0067] Implementation Scheme 10. A coating system comprising: Substrate; A first coating, the first coating being disposed on a substrate; and A second coating is applied over the first coating. The first coating comprises: Adhesive resin; and Casein, and The first coating reduces the migration of tannins from the substrate to the second coating.

[0068] Implementation Scheme 11. The coating system according to Implementation Scheme 10, wherein the substrate contains tannins, wherein the first coating further contains tannins, and wherein the second coating is substantially free of tannins.

[0069] Implementation Scheme 12. The coating system according to one of Implementation Scheme 10 or Implementation Scheme 11, wherein the substrate comprises wood, wood composite material, engineered wood, or a combination thereof.

[0070] Implementation Scheme 13. The coating system according to one of Implementation Scheme 10 or Implementation Scheme 11, wherein the substrate comprises metal, plastic, ceramic or a combination thereof.

[0071] Implementation Scheme 14. The coating system according to any one of Implementation Schemes 10 to 13, wherein the first coating is water-based.

[0072] Implementation Scheme 15. The coating system according to any one of Implementation Schemes 10 to 14, wherein the adhesive resin comprises an alkali-soluble resin.

[0073] Implementation Scheme 16. The coating system according to any one of Implementation Schemes 10 to 15, wherein the adhesive resin is a resin containing silicon-based groups.

[0074] Implementation Scheme 17. The coating system according to any one of Implementation Schemes 10 to 15, wherein the adhesive resin is cationic.

[0075] Implementation Scheme 18. The coating system according to any one of Implementation Schemes 10 to 17, wherein the adhesive resin is a member selected from the group consisting of: poly(meth)acrylic resins, epoxy resins, polyesters, polyethylene esters, alkyd resins, polyurethanes, polyisocyanates, amino resins, latexes, and silicone-based resins.

[0076] Implementation Scheme 19. A method for coating a substrate, the method comprising: Apply the first coating to the substrate; and Apply the second coating over the first coating. The first coating comprises: Adhesive resin; and Casein, and The first coating reduces the migration of tannins from the substrate to the second coating.

[0077] Implementation Scheme 20. The method according to Implementation Scheme 19, wherein the substrate comprises wood, wood composites, engineered wood, or combinations thereof.

[0078] Implementation Scheme 21. The method according to Implementation Scheme 19, wherein the substrate comprises metal, plastic, ceramic or a combination thereof.

[0079] Implementation Scheme 22. The method according to any one of Implementation Schemes 19 to 21, wherein the first coating is water-based.

[0080] Implementation Scheme 23. The method according to any one of Implementation Schemes 19 to 22, wherein the first coating has a first amount of brown before the first coating is applied to the substrate; and wherein the first coating has a second amount of brown greater than the first amount after the first coating is applied to the substrate.

[0081] Unless otherwise indicated herein or clearly contradicted by the context, all methods described herein may be performed in any suitable order. The use of language (e.g., “such as”) in any examples or descriptions provided herein is intended to illustrate the invention and not to limit its scope. Any statements herein regarding the nature or benefits of the invention or preferred embodiments are not intended to be limiting. The invention includes all modifications and equivalents of the subject matter described herein as permitted by applicable law. Furthermore, unless otherwise indicated herein or clearly contradicted by the context, the invention covers any combination of the foregoing elements in all possible variations. Descriptions of any references or patent claims herein, even if marked “prior,” are not intended to constitute a concession by such references or patents to prior art. Unclaimed language should not be considered to limit the scope of the invention. Any statement or suggestion herein that certain features constitute part of the claimed invention, unless reflected in the appended claims, is not intended to be limiting. The marking of a patent number on any product or the identification of a patent number in connection with any service should not be construed as indicating that all embodiments described herein are incorporated into such product or service.

[0082] While the implementation schemes discussed herein involve the coatings and methods discussed above, these implementation schemes are intended to be illustrative only and are not intended to limit the applicability of these implementation schemes to those discussed only herein.

[0083] The above description illustrates only several possible embodiments of various aspects of the invention, and equivalent changes and / or modifications will occur to those skilled in the art upon reading and understanding this specification and the accompanying drawings. Furthermore, while a particular feature of the invention has been disclosed with respect to only one of several embodiments, this feature may be combined with one or more other features of other embodiments, as may be desired and advantageous for any given or particular application.

[0084] Based on the foregoing teachings, additional modifications and variations of the invention are possible. Therefore, it should be understood that, within the scope of the appended claims, the invention may be practiced in ways other than those specifically described herein.

Claims

1. A tannin-blocking coating, the tannin-blocking coating comprising: Adhesive resin; and Casein, The tannin-blocking coating reduces the migration of tannins from the substrate on which the tannin-blocking coating is applied.

2. The tannin-blocking coating of claim 1, wherein the amount of casein in the tannin-blocking coating is sufficient to receive tannins migrating from the substrate during drying and substantially prevent tannins from migrating out of the tannin-blocking coating after drying.

3. The tannin-blocking coating according to claim 1 or claim 2, wherein the casein is present in the tannin-blocking coating in an amount of about 0.5% to about 10% of the total amount of the tannin-blocking coating.

4. The tannin-blocking coating according to any one of claims 1 to 3, wherein the adhesive resin is water-based.

5. The tannin-blocking coating according to any one of claims 1 to 4, wherein the adhesive resin is a resin containing silicon-based groups.

6. The tannin-blocking coating according to any one of claims 1 to 5, wherein the adhesive resin comprises an alkali-soluble resin.

7. The tannin-blocking coating according to any one of claims 1 to 6, wherein the adhesive resin is acidic.

8. The tannin-blocking coating according to any one of claims 1 to 7, wherein the adhesive resin is cationic.

9. The tannin-blocking coating according to any one of claims 1 to 8, wherein the adhesive resin is a member selected from the group consisting of: poly(meth)acrylic acids, epoxy resins, polyesters, polyethylene esters, alkyd resins, polyurethanes, polyisocyanates, amino resins, latexes, and silicone-based resins.

10. A coating system, the coating system comprising: Substrate; A first coating is disposed on the substrate; and A second coating is applied over the first coating. The first coating comprises: Adhesive resin; and Casein, and The first coating reduces the migration of tannins from the substrate to the second coating.

11. The coating system of claim 10, wherein the substrate comprises tannin, the first coating further comprises tannin, and the second coating is substantially free of tannin.

12. The coating system according to claim 10 or claim 11, wherein the substrate comprises wood, wood composites, engineered wood, or combinations thereof.

13. The coating system according to claim 10 or claim 11, wherein the substrate comprises metal, plastic, ceramic or a combination thereof.

14. The coating system according to any one of claims 10 to 13, wherein the first coating is water-based.

15. The coating system according to any one of claims 10 to 14, wherein the adhesive resin comprises an alkali-soluble resin.

16. The coating system according to any one of claims 10 to 15, wherein the adhesive resin is a resin containing silicon-based groups.

17. The coating system according to any one of claims 10 to 15, wherein the adhesive resin is cationic.

18. The coating system according to any one of claims 10 to 17, wherein the adhesive resin is a member selected from the group consisting of: poly(meth)acrylic acids, epoxy resins, polyesters, polyethylene esters, alkyd resins, polyurethanes, polyisocyanates, amino resins, latexes, and silicone-based resins.

19. A method for coating a substrate, the method comprising: The first coating is applied to the substrate; as well as Apply the second coating onto the first coating. The first coating comprises: Adhesive resin; and Casein, and The first coating reduces the migration of tannins from the substrate to the second coating.

20. The method of claim 19, wherein the substrate comprises wood, wood composites, engineered wood, or combinations thereof.

21. The method of claim 19, wherein the substrate comprises metal, plastic, ceramic, or a combination thereof.

22. The method according to any one of claims 19 to 21, wherein the first coating is water-based.

23. The method according to any one of claims 19 to 22, wherein the first coating has a first amount of brown before being applied to the substrate; and wherein the first coating has a second amount of brown greater than the first amount after being applied to the substrate.

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