Water-borne wood coating composition and wood product made of same

Abstract

The invention relates to a water-borne wood coating composition and wood products made of the water-borne wood coating composition. The aqueous woodware coating composition comprises i) an aqueous paint comprising an aqueous dispersion of polymer particles and optional additional additives comprising pigments and fillers, co-solvents, thickeners, flatting agents, antifoaming agents or any combination thereof, ii) oligosiloxanes, iii) a water-based paint comprising an aqueous dispersion of polymer particles and optional additional additives comprising a pigment filler, a co-solvent, a thickener, a leveling agent, an antifoaming agent, or any combination thereof, and iii) a water-based paint comprising an aqueous dispersion of polymer particles. The oligosiloxane has one or more functional groups capable of removing small molecules through hydrolysis, and a paint film formed by the water-borne wood coating composition has 60-degree glossiness not higher than 40.

Description

[0001] This application is a divisional application of the invention patent application filed on September 15, 2020, with application number 202010970074.3 and invention title "Waterborne Wood Coating Composition and Wood Products Made Therefrom". Technical Field

[0002] This invention relates to a water-based wood coating composition, and more particularly to a water-based wood coating composition capable of forming a low-gloss or even matte film, and wood products made therefrom. Background Technology

[0003] Currently, the environment and energy are two major challenges facing humanity. To address these challenges, the coatings industry is gradually shifting from traditional products that are highly polluting, energy-intensive, and heavily reliant on petroleum products to environmentally friendly and resource-saving products such as water-based coatings, radiation-cured coatings, powder coatings, and high-solids coatings. With the introduction of China's chemical industry standard for "Water-based Wood Coatings for Indoor Use," water-based wood coatings have experienced rapid development. Currently, R&D investment in water-based wood coatings is increasing significantly, and consumer demands for them are constantly rising.

[0004] In the wood coating market, low-gloss or matte finishes are favored by consumers for their soft sheen and smooth feel. Currently, the known matting methods for low-gloss water-based wood coatings involve using inorganic matting agents such as silica, or organic matting agents such as synthetic waxes or metal stearate salts. These matting agents primarily provide physical matting. Silica-based inorganic matting agents can create a microscopically rough surface after the coating dries, resulting in reduced gloss or even a matte finish. Synthetic wax-based organic matting agents can float on the outermost surface after drying, modifying the coating and affecting its gloss. However, these known matting agents all have some drawbacks. From a cost perspective, silica-based inorganic matting agents are the most convenient for formulating water-based matte wood coatings. However, this method suffers from powder settling, poor coating feel, and poor transparency. Organic matting agents such as synthetic waxes and metal stearate salts are not widely used in the formulation of water-based matte wood coatings due to their high cost or insufficient performance.

[0005] Therefore, the coatings industry urgently needs to improve water-based wood coatings that can form low-gloss or even matte finishes. Summary of the Invention

[0006] This invention provides a water-based wood coating composition comprising i) a water-based base paint, the water-based base paint comprising an aqueous dispersion of polymer particles and optional additional additives, the additional additives including pigments, fillers, cosolvents, thickeners, leveling agents, defoamers, or any combination thereof; ii) an oligomeric siloxane having one or more hydrolyzable small molecule functional groups, wherein the coating film formed by the water-based wood coating composition has a gloss level of not more than 40 at a 60-degree angle.

[0007] In some embodiments of the present invention, the waterborne base paint contained in the waterborne wood coating composition comprises an aqueous dispersion of polymer particles having one or more active hydrogen functional groups.

[0008] In some embodiments of the present invention, the oligomeric siloxane contained in the waterborne wood coating composition, in addition to having one or more functional groups capable of hydrolyzing and removing small molecules, also contains one or more segments having active hydrogen reactive functional groups. In this embodiment, the oligomeric siloxane may have a structure represented by the following general formula 1: (General Formula 1) in At least one of R1, R2, R3, R4, R5, and R6 is a functional group capable of hydrolyzing small molecules, wherein the functional group capable of hydrolyzing small molecules is selected from C1-C6 alkoxy, C2-C6 olefin, C6-C6 alkoxy, C2-C6 olefin ... 10 Aryloxy, C1-C6 alkyloxy, C6-C 10 Aromatic acyloxy, C1-C6 alkyl ketone oxime and C6-C 10 One or more of the aromatic ketoxime groups, preferably selected from C1-C6 alkoxy groups; and At least one of R1, R2, R3, R4, R5, and R6 is a fragment containing an active hydrogen reactive functional group, wherein the active hydrogen reactive functional group is selected from one or more of epoxy, hydroxyl, amino, and isocyanate groups, preferably selected from epoxy groups; and m is not 0, and preferably is an integer from 1 to 10.

[0009] In other embodiments of the invention, the oligomeric siloxane comprising the waterborne wood coating composition, in addition to having one or more hydrolyzable small molecule functional groups, also comprises two or more segments having active hydrogen reactive functional groups. In this embodiment, the oligomeric siloxane may have a structure represented by the following general formula 2: (General Formula 2) R A The term "functional group" indicates a functional group capable of hydrolyzing small molecules, wherein the functional group capable of hydrolyzing small molecules is selected from C1-C6 alkoxy, C2-C6 alkenoxy, and C6-C6 alkoxy groups.10 Aryloxy, C1-C6 alkyloxy, C6-C 10 Aromatic acyloxy, C1-C6 alkyl ketone oxime and C6-C 10 One or more of the aromatic ketoxime groups, preferably selected from C1-C6 alkoxy groups; and R B This refers to a segment containing an active hydrogen reactive functional group, wherein the active hydrogen reactive functional group is selected from one or more of epoxy, hydroxy, amino, and isocyanate groups, preferably selected from epoxy groups; and m is not 0, and preferably is an integer from 1 to 10.

[0010] In some embodiments of the present invention, the oligomeric siloxanes contained in the water-based wood coating composition are insoluble in water.

[0011] Another aspect of the present invention provides a wood article comprising a wood substrate having at least one main surface; and at least one paint film formed by applying a water-based wood coating composition of the present invention directly or indirectly onto the main surface.

[0012] The inventors of this invention have surprisingly discovered that by adding oligomeric siloxanes having one or more hydrolyzable small molecule functional groups to a waterborne base paint during the formulation of waterborne wood coating compositions, the resulting waterborne wood coating compositions can achieve a chemically produced matte effect, thereby forming a reduced gloss or even matte paint film.

[0013] The inventors of this invention were even more surprised to discover that, in the formulation of waterborne wood coating compositions, the addition of an oligomeric siloxane, which, in addition to having one or more functional groups capable of hydrolyzing and removing small molecules, also contains one or more fragments with active hydrogen reactive functional groups, and preferably two or more fragments with active hydrogen reactive functional groups, and combining it with an aqueous base paint containing an aqueous dispersion of polymer particles with active hydrogen functional groups, not only enables the chemical matting of the paint film and promotes the formation of a matte or even glossy paint film, but also allows it to participate in the film-forming process, thereby improving the properties of the paint film, such as its chemical resistance, especially its alkali resistance.

[0014] Details of one or more embodiments of the present invention are set forth in the following description. Other features, objects, and advantages of the invention will become clear from the description and claims. Attached Figure Description

[0015] Figure 1The images show the coating surfaces of the water-based wood coating composition of Example 2 according to the present invention and the water-based base paint of control sample 1, analyzed by electron microscopy. The left image is the coating film of control sample 1, and the right image is the coating film of Example 2 according to the present invention.

[0016] Figure 2 The infrared spectra of the waterborne wood coating composition of Example 2 according to the present invention, the oligomeric siloxane incorporated in the waterborne wood coating composition of Example 2, and the waterborne base paint of control sample 1 are shown, measured by Fourier transform attenuated total reflectance infrared spectroscopy. The top curve is the coating of control sample 1, the middle curve is the coating film of oligomeric siloxane, and the bottom curve is the coating of Example 2 according to the present invention.

[0017] definition In this document, the terms “a”, “the”, “at least one”, and “one or more” are used interchangeably, as are cases where no quantifier is used. Therefore, for example, a component containing “a” additive can be interpreted as meaning that the component contains “one or more” additives.

[0018] When a composition is described as including or comprising specific components, it is anticipated that optional components not covered by the present invention are not excluded from the composition, and that the composition may be constituted or composed of the components involved. Similarly, when a method is described as including or comprising specific process steps, it is anticipated that optional process steps not covered by the present invention are not excluded from the method, and that the method may be constituted or composed of the process steps involved.

[0019] For simplicity, this paper only explicitly discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form an undefined range; and any lower limit can be combined with other lower limits to form an undefined range, just as any upper limit can be combined with any other upper limit to form an undefined range. Furthermore, although not explicitly stated, every point or individual value between the endpoints of a range is included within that range. Therefore, each point or individual value can serve as its own lower or upper limit and be combined with any other point or individual value, or with other lower or upper limits, to form an undefined range.

[0020] In this article, "coating" and "coating film" have the same meaning, both referring to the coating formed by applying and drying a water-based wood coating composition.

[0021] When referring to "waterborne wood coating composition", the phrase "the paint film formed by the waterborne wood coating composition has a gloss of not more than 40 degrees at a 60-degree angle" means that the paint film formed by the waterborne wood coating composition exhibits a low gloss effect, and therefore the above-mentioned waterborne wood coating composition can also be called a low-gloss waterborne wood coating composition.

[0022] In the context of this invention, the term "oligosiloxane" refers to a class of oligomers with repeating Si-O bonds as the main chain and organic groups directly attached to silicon atoms, wherein the organic groups may include alkyl, aryl, alkoxy, aryloxy or other organic groups known to those skilled in the art.

[0023] When used in relation to "oligosiloxanes," the term "one or more hydrolyzable small molecule functional groups" refers to functional groups that are directly attached to silicon atoms on the oligosiloxane backbone and can undergo hydrolysis in the presence of an aqueous medium to form small molecules that can be removed from the system, such as volatile small molecules. As an example, the hydrolyzable small molecules include, but are not limited to, alcohols, carboxylic acids, oximes, water, etc.

[0024] When referring to "oligosiloxanes," the term "insoluble in water" means that the oligosiloxane cannot be uniformly dispersed at the molecular scale in an aqueous medium (e.g., water) to form a homogeneous solution. In some embodiments of the invention, the oligosiloxane can be dispersed in water as nanoscale particles, resulting in a transparent and clear dispersion, or it can be dispersed in water as micrometer-scale particles, resulting in an opaque or semi-transparent dispersion that is mist-like.

[0025] In the context of this invention, the term "matte powder" includes silica matting agents, synthetic wax matting agents, and stearate matting agents. When used with respect to a "waterborne wood coating composition," the term "substantially free of matte powder" means that the components of the waterborne wood coating composition, and the coating composition formed therefrom, do not contain any additional matte powders as described above, preferably none known in the art. When the phrase "substantially free of" is used herein, such a phrase is not intended to exclude the presence of trace amounts of matte powders that may be present as environmental contaminants or due to environmental pollution.

[0026] As used herein, the term "oligomer" or "oligomer" refers to a structure that generally comprises a polymer containing a relatively small number of repeating units, either actually or conceptually derived from molecules of relatively low molecular weight. Typically, in oligomers, the addition or removal of even a single repeating unit can affect the properties of the resulting oligomer.

[0027] When used in this specification and claims, the terms “comprising” and “including” and their variations are not restrictive.

[0028] The terms "preferred" and "ideally" refer to embodiments of the invention that provide certain benefits 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, nor is it intended to exclude other embodiments from the scope of the invention. Detailed Implementation

[0029] The present invention provides a waterborne wood coating composition comprising i) a waterborne base paint, said waterborne base paint comprising an aqueous dispersion of polymer particles and optional additional additives, said additional additives including pigments, fillers, cosolvents, thickeners, leveling agents, defoamers or any combination thereof; ii) an oligomeric siloxane having one or more hydrolyzable small molecule functional groups, wherein the coating film formed by said waterborne wood coating composition has a gloss level of not more than 40 at a 60-degree angle.

[0030] As described above, the waterborne wood coating composition according to the present invention can form a paint film with a 60-degree gloss level of not more than 40. Therefore, the waterborne wood coating composition according to the present invention can also be referred to as a low-gloss waterborne wood coating composition. Preferably, the paint film formed by the waterborne wood coating composition according to the present invention preferably has a 60-degree gloss level of not more than 35, more preferably a 60-degree gloss level of not more than 30, even more preferably a 60-degree gloss level of not more than 25, and even more preferably a 60-degree gloss level of not more than 20. Therefore, the preferred waterborne wood coating composition according to the present invention can also be referred to as a matte waterborne wood coating composition.

[0031] In embodiments of the present invention, the waterborne wood coating composition comprises an oligomeric siloxane, which is present as a separate component in a distinguishable form within the waterborne wood coating composition. In the context of this invention, "oligomeric siloxane" refers to a class of oligomers with repeating Si-O bonds as the main chain and organic groups directly attached to silicon atoms, wherein the organic groups may include alkyl, aryl, alkoxy, aryloxy, or other organic groups known to those skilled in the art.

[0032] In embodiments of the invention, the oligomeric siloxane may have one or more functional groups capable of hydrolyzing and removing small molecules. As described above, these functional groups are directly attached to the silicon atoms of the oligomeric siloxane backbone and can undergo hydrolysis in the presence of an aqueous medium, thereby removing small molecules, such as volatile small molecules. The formation of these small molecules causes pitting on the surface of the paint film formed from the aqueous wood coating composition containing the oligomeric siloxane, resulting in a rough surface. Suitable examples of hydrolyzable small molecule functional groups include hydroxyl, alkoxy, alkenoxy, aryloxy, alkanoyloxy, aryloxy, alkanone oxime, and arylone oxime. As an example, the hydrolyzable small molecules include, but are not limited to, alcohols, carboxylic acids, oximes, water, etc.

[0033] To more clearly illustrate the process of hydrolysis and removal of small molecules by oligomeric siloxanes during the film formation of paints, the following illustrative examples are provided: Process 1: ≡Si-OR + 3H2O →≡Si-OH + 3ROH↑; Process 2: ≡Si-OH + HO-Si≡ → ​​≡Si-O-Si≡ + H₂O; Process 3: ≡Si-OR + HO-Si≡ → ​​≡Si-O-Si≡ + ROH; Process 4: Polymer particles -OH+ HO-Si / RO-Si≡ → ​​≡Si-O-Si≡ + H2O / ROH.

[0034] As shown in the above process of hydrolysis to remove small molecules, during the film-forming process of the waterborne wood coating composition, oligomeric siloxanes containing one or more functional groups capable of hydrolyzing and removing small molecules can hydrolyze to generate volatile small molecules (e.g., alcohols), and / or can self-condense to generate water molecules or volatile small molecules, and / or can react with hydroxyl groups present in the polymer particles to generate water molecules or volatile small molecules. In some embodiments of the present invention, the hydroxyl groups present in the polymer particles are introduced by subjecting polymer particles with carboxylic acid functional groups to a ring-opening reaction with oligomeric siloxanes with epoxy functional groups, thereby introducing hydroxyl groups into the polymer particles. During the film formation process, one or more of the above processes for hydrolysis and removal of small molecules can be carried out simultaneously or sequentially.

[0035] The inventors of this invention have surprisingly discovered that incorporating the aforementioned oligomeric siloxanes with one or more hydrolyzable small molecule functional groups into water-based base paints results in water-based wood coating compositions with low gloss, and even water-based wood coating compositions with a matte finish. Unbound by any theoretical constraints, the inventors believe that: compared to small molecule silanes, the hydrolysis of oligomeric siloxanes with one or more hydrolyzable functional groups is a much slower process. The resulting volatile small molecules are continuously released in the form of bubbles, rising to the surface of the paint film, and then bursting to form pits, creating a rough surface. Furthermore, during hydrolysis, the oligomeric siloxanes also self-condense into organosilicon microparticles. These organosilicon microparticles have a lower surface tension than the surrounding resin, thus causing pits in the paint film and creating a rough surface. Through the synergistic effect of these two factors, the oligomeric siloxanes can effectively reduce the gloss of the paint film, thereby allowing the formulation of water-based wood coating compositions with reduced gloss or a matte finish.

[0036] In one embodiment of the invention, the oligomeric siloxane further comprises one or more segments having reactive hydrogen functional groups. The incorporation of this oligomeric siloxane allows it to not only provide a matte finish to the coating film but also to undergo a crosslinking reaction to participate in the formation of the coating film, thereby improving the mechanical properties of the coating film.

[0037] In this embodiment, as an example, the oligomeric siloxane has a structure represented by general formula 1: (General Formula 1) in At least one of R1, R2, R3, R4, R5, and R6 is a functional group capable of hydrolyzing small molecules, wherein the functional group capable of hydrolyzing small molecules is selected from C1-C6 alkoxy, C2-C6 olefin, C6-C6 alkoxy, C2-C6 olefin ... 10 Aryloxy, C1-C6 alkyloxy, C6-C 10 Aromatic acyloxy, C1-C6 alkyl ketone oxime and C6-C 10 One or more of the aromatic ketoxime groups, preferably selected from C1-C6 alkoxy groups; and At least one of R1, R2, R3, R4, R5, and R6 is a fragment containing an active hydrogen reactive functional group, wherein the active hydrogen reactive functional group is selected from one or more of epoxy, hydroxyl, amino, and isocyanate groups, preferably selected from epoxy groups; and m is not 0, and preferably is an integer from 1 to 10.

[0038] In another embodiment of the invention, the oligomeric siloxane further comprises two or more segments with reactive functional groups containing active hydrogen. The incorporation of this oligomeric siloxane not only provides a matte finish to the coating film but also provides multiple functional groups capable of crosslinking with polymer particles, thus resulting in a coating film with improved chemical resistance, particularly improved alkali resistance.

[0039] In this embodiment, as an example, the oligomeric siloxane has the structure represented by general formula 2: (General Formula 2) R A The term "functional group" indicates a functional group capable of hydrolyzing small molecules, wherein the functional group capable of hydrolyzing small molecules is selected from C1-C6 alkoxy, C2-C6 alkenoxy, and C6-C6 alkoxy groups. 10 Aryloxy, C1-C6 alkyloxy, C6-C 10 Aromatic acyloxy, C1-C6 alkyl ketone oxime and C6-C 10 One or more of the aromatic ketoxime groups, preferably selected from C1-C6 alkoxy groups; and R B This refers to a segment containing an active hydrogen reactive functional group, wherein the active hydrogen reactive functional group is selected from one or more of epoxy, hydroxy, amino, and isocyanate groups, preferably selected from epoxy groups; and m is not 0, and preferably is an integer from 1 to 10.

[0040] In some embodiments of the invention, the oligomeric siloxane is insoluble or sparingly soluble in water. The inventors of the invention have surprisingly discovered that this solubility property of the oligomeric siloxane in an aqueous medium is particularly advantageous for the formation of surface roughness in the paint film. Therefore, in a preferred embodiment of the invention, the oligomeric siloxane can be dispersed in an aqueous medium in the form of nanoparticles or microparticles, preferably dispersed in an aqueous base paint.

[0041] The aforementioned oligomeric siloxanes are either homemade or commercially available. For example, COATOSIL MP-200, commercially available from Momentive, or JH-OP17, commercially available from Jingzhou Jianghan Fine Chemical Co., Ltd., can be used.

[0042] According to embodiments of the present invention, the amount of oligomeric siloxane can be varied within an appropriate range as needed. In some embodiments of the present invention, the oligomeric siloxane may be present in an amount of 1 to 10 wt% relative to the total weight of the waterborne base paint, preferably in an amount of 3 to 10 wt%, more preferably in an amount of 4 to 10 wt%, and even more preferably in an amount of 4-8 wt%. Oligomeric siloxanes within the above-mentioned dosage range are suitable for reducing the gloss of the waterborne wood coating composition and improving the chemical resistance of the film formed by the waterborne wood coating composition.

[0043] In embodiments of the present invention, the waterborne wood coating composition includes a waterborne base paint in addition to oligomeric siloxanes. The waterborne base paint, as the main component of the waterborne wood coating composition, includes conventional components used to formulate the waterborne wood coating composition, including but not limited to, an aqueous dispersion of polymer particles, water, additional additives, etc.

[0044] In embodiments of the present invention, the waterborne base paint comprises an aqueous dispersion of polymer particles. When used herein, the term "aqueous dispersion of polymer particles" refers to a stable dispersion of synthetic resin (i.e., polymer) in particulate form in an aqueous liquid medium, optionally with the aid of a suitable dispersing agent such as a surfactant. Therefore, in this application, when referring to a polymer, the terms "aqueous latex" and "aqueous dispersion" may be used interchangeably unless otherwise stated. Methods for preparing aqueous latex are known in the art, for example, they can be carried out using emulsion polymerization processes known to those skilled in the art. Such emulsion polymerization processes typically include the following steps: optionally, under the action of a suitable emulsifier and / or dispersant stabilizer and by means of stirring, dispersing polymerizable monomers into an emulsion in water, and initiating polymerization of the monomers, for example, by adding an initiator.

[0045] It is known that polymer particles in aqueous latex can be modified to obtain aqueous latex with desired properties. In one embodiment of the invention, the polymer particles are modified by active hydrogen functional groups. On one hand, active hydrogen can be provided by functional groups such as -COOH, -OH, -SH, secondary amino, and primary amino groups. Furthermore, some functional groups, such as ester groups (especially carboxylic acid ester groups), thioether groups, or anhydride groups (especially carboxylic acid anhydride groups), can be converted, for example, by hydrolysis into functional groups capable of providing active hydrogen. Therefore, in the present invention, polymer particles having one or more active hydrogen functional groups refer to any polymer particles that inherently contain functional groups capable of providing active hydrogen and / or any polymer particles that can be converted into functional groups capable of providing active hydrogen during system preparation and / or application.

[0046] In embodiments of the present invention, an aqueous dispersion of polymer particles having one or more active hydrogen functional groups is considered as a film-forming resin component in an aqueous base paint. On one hand, this resin component acts as a binder to provide adhesion between the paint film and the substrate, and to hold the components (such as fillers) in the aqueous base paint together and impart a certain cohesive strength to the paint film. On the other hand, these polymer particles exhibit good reactivity with oligomeric siloxanes having reactive active hydrogen functional groups, thereby achieving crosslinking of the polymer chains and forming a paint film coating with a three-dimensional network structure.

[0047] In some embodiments of the present invention, the polymer particles in the aqueous latex may have one or more active hydrogen functional groups selected from -COOH, -OH, -SH, secondary amino and primary amino groups, preferably carboxyl-functionalized.

[0048] In some preferred embodiments of the present invention, the aqueous dispersion of the polymer particles includes aqueous dispersions of vinyl acetate resins, aqueous dispersions of acrylic resins, aqueous dispersions of organosilicon resins, aqueous dispersions of polyurethane resins, aqueous dispersions of polyurethane-polyacrylic resins, aqueous dispersions of fluoropolymer resins, or any combination thereof.

[0049] In embodiments of the invention, the polymer particles in the aqueous dispersion have a certain range of particle sizes, which can be measured using Z-average particle size, a term known in the art, referring to the particle size measured using dynamic light scattering methods, such as a Marvlen Zetasizer 3000HS microparticle size analyzer. Preferably, the polymer particles in the aqueous dispersion can have a particle size in the range of 50 nm to 200 nm. The inventors of the invention have surprisingly discovered that aqueous dispersions of polymer particles having the above-mentioned particle size range are particularly suitable for formulating waterborne wood coating compositions, which exhibit suitable rheological and coatability properties.

[0050] In embodiments of the present invention, the aqueous dispersion of the polymer particles has a solid content of 30-50%. From an industrial perspective, an aqueous dispersion of polymer particles with the above-mentioned solid content is the most readily available. The above-mentioned aqueous dispersion of polymer particles can be prepared in-house or is a commercially available product. As an example, commercially available aqueous dispersions of Dow 3311 acrylates, Allnex 6716 acrylates, DSM E129 polyurethane polyacrylate, DSM R2180 polyurethane, or Alberdingk U9900 polyurethane can be used.

[0051] According to embodiments of the present invention, the amount of the aqueous dispersion of polymer particles can vary over a wide range, and its total amount relative to the total weight of the aqueous base paint can range from about 60 wt% to about 85 wt%. In some embodiments, the amount of the aqueous dispersion of polymer particles can range from 75 wt% to 85 wt%.

[0052] According to some embodiments of the present invention, the water-based base paint may further contain a certain amount of water-based carrier, such as water, to obtain a suitable coating viscosity.

[0053] According to some embodiments of the invention, water-based base paints may, as needed, contain pigments and fillers to impart the desired color and / or strength to the resulting paint film or coating. The term "pigment and filler" as used herein refers to any volume-increasing agent suitable for coatings, which may be organic or inorganic, for example, in particulate form. There are no particular limitations on the shape of the particles, which may have any suitable shape. The average particle size can vary over a wide range, for example, from about 10 nanometers to about 50 micrometers. Some particulate materials, in addition to acting as volume-increasing agents in coatings, impart one or more desired properties to the composition and / or the coating formed from the composition. For example, some particulate materials can impart a desired color to the composition and the coating obtained from the composition. In this case, such particulate materials are also referred to as "pigments". Some particulate materials can improve chemical and / or physical properties, particularly the mechanical properties of the coating obtained from the composition. In this case, such particulate materials are also referred to as "fillers".

[0054] In embodiments of the present invention, suitable exemplary pigments and fillers include, for example, kaolin, titanium dioxide, calcium carbonate, diatomaceous earth, talc, barium sulfate, magnesium aluminum silicate, silicon dioxide, and any combination thereof. In a preferred embodiment, the filler may include titanium dioxide, kaolin, calcium carbonate, diatomaceous earth, or a combination thereof.

[0055] According to the present invention, the total amount of pigments and fillers can vary within a wide range, for example, the total amount relative to the total weight of the water-based base paint is from about 0% to about 60% by weight, preferably from about 0.1% to about 60% by weight, more preferably from about 10% to about 50% by weight.

[0056] According to embodiments of the invention, the waterborne base paint may optionally further comprise other additional additives commonly used in waterborne wood coating compositions, which do not adversely affect the coating composition or the cured coating obtained therefrom. Suitable additives include, for example, those agents that improve the processability or manufacturing properties of the composition, enhance the aesthetics of the composition, or improve specific functional properties or characteristics (such as adhesion to the substrate) of the coating composition or the cured composition obtained therefrom. Additional additives that may be included include, for example, cosolvents, defoamers, leveling agents, thickeners, lubricants, anti-migration agents, mildew inhibitors, preservatives, wetting agents, antifungal and bactericidal agents, rust inhibitors, antioxidants, dispersants, adhesion promoters, UV stabilizers, pH adjusters, film-forming aids, or combinations thereof. The amounts of each optional component are sufficient to achieve their intended purpose, but preferably, such amounts do not adversely affect the waterborne wood coating composition or the coating film obtained therefrom. In some embodiments of the invention, the waterborne base paint may further comprise one or more of cosolvents, defoamers, leveling agents, thickeners, surfactants, and bactericides. In one embodiment of the present invention, the water-based base paint may further include one or more of the following: a cosolvent (including but not limited to dipropylene glycol monomethyl ether (DPM) and dipropylene glycol monobutyl ether (DPnB)), a defoamer, a leveling agent, and a thickener.

[0057] In one specific embodiment of the present invention, the water-based base paint comprises, relative to the total weight of the water-based base paint, An aqueous dispersion of the polymer particles comprising 60-85 wt%; 10-30wt% water; 0-20 wt% additional additives, wherein one or more of the additional additives are selected from self-solvents, defoamers, leveling agents and thickeners.

[0058] In some embodiments of the invention, the waterborne wood coating composition is substantially free of matting agents, and preferably completely free of matting agents.

[0059] In some embodiments of the present invention, a waterborne wood coating composition formed by mixing a waterborne base paint with an oligomeric siloxane is applied to an aged polyurethane panel with a wet film thickness of 150 micrometers and air-dried for 7 days. The resulting coating film has a gloss reduction of 10% or more, preferably 30% or more, more preferably 50% or more, compared with a control coating film formed in the same manner with the waterborne base paint.

[0060] In some embodiments of the invention, a waterborne wood coating composition formed by mixing a waterborne base paint with an oligomeric siloxane is applied to an aged polyurethane panel with a wet film thickness of 150 micrometers and air-dried for 7 days. The resulting coating film has improved chemical resistance compared to conventional coating films with similar gloss, and preferably improved alkali resistance.

[0061] In some embodiments of the present invention, when comparing a paint film formed by the waterborne wood coating composition of the present invention with a control paint film formed by a control waterborne base paint and a commercially available matting agent, the paint film of the present invention exhibits higher transparency at the same gloss level.

[0062] The preparation of the waterborne wood coating composition according to the present invention can be achieved by any suitable mixing method known to those skilled in the art. For example, the waterborne wood coating composition can be prepared by adding an aqueous emulsion, water, and any existing additives to a container, and then stirring the resulting mixture until homogeneous to form an aqueous base paint; then mixing the resulting aqueous base paint with an appropriate amount of oligomeric siloxane to obtain the final waterborne wood coating composition.

[0063] The waterborne wood coating composition of the present invention can be applied by conventional methods known to those skilled in the art, such as by scraping, spraying, rolling or other conventional coating methods known to those skilled in the art.

[0064] Wood products The present invention also provides a wood product comprising: a wood substrate having at least one main surface; and at least one paint film formed by a water-based wood coating composition according to an embodiment of the present invention, applied directly or indirectly to the main surface.

[0065] In embodiments of the wood products of the present invention, the substrate is a wood-based substrate. Any suitable wood-based substrate known in the art can be used. In this application, the term "wood-based substrate" refers to any cellulose / lignin material derived from the hard, fibrous tissue of the stems and roots of trees or other woody plants. Wood includes, for example, hardwood and softwood timber cut directly from trees, and engineered wood composites made from wood strips, wood chips, wood fibers, or wood veneers. Examples of wood composites include, but are not limited to, plywood, oriented strand board (OSB), medium-density fiberboard (MDF), particleboard, etc. As an example of particleboard, melamine board, i.e., melamine-treated particleboard, can be used.

[0066] As an example, one or more of the following wood-based materials may be used: hardwood, chestnut, oak, red chestnut, camellia, eucalyptus, Douglas fir, Japanese cedar, American cypress, Japanese red pine, Japanese cypress, water walnut, black walnut, maple, Japanese beech, Japanese paulownia, birch, sage, magnolia, ash, teak, oak, catalpa, camphorwood, cedar, oak, and rubberwood.

[0067] As described above, the water-based wood coating composition according to the present invention is suitable for application onto the surface of a wood substrate as a topcoat, thereby providing a low-gloss or matte effect to the surface of the wood substrate.

[0068] The following examples describe the disclosure of this invention in more detail. These examples are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of this disclosure. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are based on weight, and all reagents used in the examples are commercially available and ready for use without further processing.

[0069] Test methods Electron microscopy test: The water-based wood coating composition was coated onto a polyvinyl chloride (PVC) black film with a wet film thickness of 150 micrometers and air-dried for 7 days. The morphology of the dry film surface was then observed using a LEICA DVM6.

[0070] Infrared test: The water-based wood coating composition was coated onto a polyvinyl chloride (PVC) black film with a wet film thickness of 150 micrometers and air-dried for 7 days. The attenuation total reflectance test of the sample coating was performed using a Thermo Nicolet Nexus 470-FTIR infrared spectrometer.

[0071] Glossiness: A water-based wood coating composition was applied to an aged polyurethane panel at a wet film thickness of 150 microns and air-dried for 7 days. The gloss of the sample was then tested using a BYK4565 micrometer gloss meter. o Glossiness.

[0072] transparency: The water-based wood coating composition was coated onto a glass panel with a wet film thickness of 150 micrometers and air-dried for 7 days. The transparency of the sample was then tested using the LS108 of Shenzhen Linshang Technology Co., Ltd. under visible light at 550 nm, blue light at 430 nm, and violet light at 395 nm.

[0073] Chemical resistanceThe waterborne wood coating composition was applied to an aged polyurethane panel with a wet film thickness of 150 micrometers and air-dried for 7 days. The chemical resistance of the waterborne wood coating composition was tested according to the test standards GB / T 3324-2008 and GB / T 23999-2009 and scored. A grade of 5 indicates the best chemical resistance and 0 indicates the worst chemical resistance.

[0074] Example The raw materials used in this example are listed in Table 1 below.

[0075] Table 1.

[0076] Waterborne wood coating compositions According to the dosage shown in Table 2, water-based latex, cosolvent, defoamer, leveling agent, thickener and water are added to the production tank in sequence and stirred until uniform; then, oligomeric siloxanes as shown in Table 2 are added to the production tank and stirred until uniform, then discharged, filtered and packaged to obtain the water-based wood coating composition according to the embodiment of the present invention.

[0077] As a control, water-based latex, cosolvent, defoamer, leveling agent, thickener and water were added to the production tank in sequence and stirred until homogeneous; then, different types of commercial matting agents BCR 1693, SYLOID 7000 or TS-100 in the amounts shown in Table 2 were added to the production tank, stirred until homogeneous, and then discharged, filtered and packaged to obtain the control water-based wood coating composition.

[0078]

[0079] Table 2: Components and Dosage of Waterborne Wood Coating Compositions Optical properties of waterborne wood coating compositions According to the test method shown in the test section, a water-based base paint without oligomeric silicones was used as control sample 1. It was compared with the water-based wood coating compositions 1-4 of the present invention and the comparative water-based wood coating composition example AF. These coating compositions were applied to aged polyurethane panels with a wet film thickness of 150 micrometers and air-dried for 7 days. The gloss of the samples was then tested using a BYK4565 gloss meter. o Glossiness.

[0080] In addition, a coating composition containing small molecule epoxy silane A187 incorporated into a water-based base paint was used as control sample 2, and the 60% of the resulting paint film was measured as described above. o Glossiness.

[0081] The test results are summarized in Table 3 below.

[0082] Table 3. Gloss of the coating film formed by water-based wood coating compositions

[0083] As shown in Table 3 above, incorporating oligomeric siloxanes into water-based base paints can significantly reduce the gloss of the coating composition, and can even yield a matte coating composition, i.e., 60%. o Coating compositions with a gloss level below 25 exhibit superior matting properties compared to conventional commercial matting agents. In contrast, incorporating small-molecule epoxy silanes, such as A-187 (γ-glycidoxypropyltrimethoxysilane, possessing hydrolyzable functional groups), into waterborne base paints does not significantly reduce the gloss of the coating composition. Therefore, incorporating oligomeric polysiloxanes with hydrolyzable functional groups into waterborne base paints is essential for reducing the surface gloss of the paint film.

[0084] To further investigate the surface characteristics of the paint film, the inventors performed electron microscopy and infrared analysis on the surface of the paint film formed from the coating composition of Example 2. The results are shown in... Figure 1 and Figure 2 In the middle. By Figure 1 It is evident that the incorporation of oligomeric siloxanes into the water-based base paint significantly increases the surface roughness of the resulting paint film, resulting in numerous pits on the film surface. It is speculated that some of these pits are due to the condensation of the oligomeric siloxanes into organosilicon microparticles, and the lower surface tension of these organosilicon microparticles compared to the surrounding resin. In contrast, the surface of control sample 1, which does not contain oligomeric siloxanes, is smoother. Furthermore, from... Figure 2 The infrared spectroscopy results show that oligomeric epoxy siloxanes undergo cross-linking reactions with carboxyl-functionalized aqueous latex during film formation, as indicated by the characteristic carboxyl peak at 1728 cm⁻¹. -1 The absorption intensity decreases.

[0085] Next, the waterborne wood coating composition of Comparative Example DF and the waterborne wood coating composition of Example 2, which have similar gloss levels, were compared, and the transparency of each coating film was measured. The test results are summarized in Table 4 below.

[0086] Table 4. Transparency of the film formed by water-based wood coating compositions

[0087] As can be seen from the results shown in Table 4 above, the waterborne wood coating composition obtained by incorporating oligomeric siloxanes into the waterborne base paint has comparable transparency, or even better transparency, compared with the control waterborne wood coating composition with similar gloss.

[0088] Film properties of water-based wood coating compositions Following the test methods described in the test section, the waterborne wood coating composition 2 of the present invention and a comparative waterborne wood coating composition example DF with similar gloss were compared. The chemicals shown in Table 5 below were applied to the paint films formed by these coating compositions for a certain period of time, and the resistance to the chemicals was tested. The test results are summarized in Table 5 below.

[0089] Table 5. Chemical resistance of the coating film formed by water-based wood coating compositions

[0090] As can be seen from the results in Table 5, compared with the comparative waterborne wood coating composition DF, which has a similar gloss, the waterborne wood coating composition obtained by incorporating oligomeric siloxanes into the waterborne base paint according to the embodiments of the present invention has improved chemical resistance, especially significantly improved alkali resistance.

[0091] Other water-based wood coating compositions To verify the matting effect of the oligomeric siloxane of the present invention in other waterborne base paints, DOW 3311 in Example 2 was replaced with the same amount of Allnex 6716, DSM E-129 and DSM R2180 respectively, and waterborne wood coating compositions according to the present invention were prepared as described above.

[0092] These coating compositions were then applied to aged polyurethane panels at a wet film thickness of 150 micrometers and air-dried for 7 days. The gloss of the samples was then tested using a BYK4565 gloss meter at 60°C. o Glossiness. The test results are shown in Table 6 below.

[0093] Table 6. Gloss of the coating film formed by other water-based wood coating compositions

[0094] As can be seen from the results in Table 6 above, the oligomeric siloxanes of the present invention are suitable for water-based base paints formulated from various water-based latexes, have a very wide range of applications, and are worth promoting.

[0095] This application also includes the following exemplary embodiments: Embodiment 1. A water-based wood coating composition comprising... i) A water-based paint, wherein the water-based paint comprises an aqueous dispersion of polymer particles and optionally at least one additional additive, wherein the at least one additional additive comprises at least one pigment / filler, at least one cosolvent, at least one thickener, at least one leveling agent, at least one defoamer, or any combination thereof. ii) At least one oligomeric siloxane, said at least one oligomeric siloxane having one or more functional groups that can be hydrolyzed to remove small molecules. The paint film formed by the water-based wood coating composition has a gloss level of no more than 40 at a 60-degree angle.

[0096] Implementation Method 2. The water-based wood coating composition as described in Implementation Method 1, wherein the water-based wood coating composition is substantially free of matting agents.

[0097] Embodiment 3. The water-based wood coating composition as described in any one of Embodiments 1 to 2, wherein the small molecule comprises at least one alcohol, at least one carboxylic acid, at least one oxime, water, or a combination thereof.

[0098] Embodiment 4. The waterborne wood coating composition as described in any one of Embodiments 1 to 3, wherein the polymer particles have one or more active hydrogen functional groups.

[0099] Embodiment 5. The waterborne wood coating composition as described in any one of Embodiments 1 to 4, wherein the polymer particles have one or more active hydrogen functional groups selected from -COOH, -OH, -SH, secondary amino and primary amino or combinations thereof.

[0100] Embodiment 6. The waterborne wood coating composition as described in Embodiment 5, wherein the one or more active hydrogen functional groups are carboxyl-functionalized.

[0101] Embodiment 7. The waterborne wood coating composition according to any one of Embodiments 1 to 6, wherein the waterborne dispersion of the polymer particles includes a waterborne dispersion of vinyl acetate polymer particles, a waterborne dispersion of acrylic polymer particles, a waterborne dispersion of silicone polymer particles, a waterborne dispersion of polyurethane polymer particles, a waterborne dispersion of polyurethane-polyacrylic polymer particles, a waterborne dispersion of fluoropolymer polymer particles, or any combination thereof.

[0102] Embodiment 8. A waterborne wood coating composition as described in any one of Embodiments 1 to 7, wherein the at least one oligomeric siloxane further comprises one or more segments having at least one active hydrogen reactive functional group.

[0103] Embodiment 9. A waterborne wood coating composition as described in any one of Embodiments 1 to 8, wherein the at least one oligomeric siloxane has a structure represented by general formula 1: (General Formula 1) in At least one of R1, R2, R3, R4, R5, and R6 is a functional group capable of hydrolyzing and removing small molecules, wherein the functional group is selected from C1-C6 alkoxy, C2-C6 alkenoxy, C6-C6 alkoxy, C2 ... 10 Aryloxy, C1-C6 alkyloxy, C6-C 10 Aromatic acyloxy, C1-C6 alkyl ketone oxime and C6-C 10 One or more of the aromatic ketoxime groups, preferably selected from C1-C6 alkoxy groups; and At least one of R1, R2, R3, R4, R5, and R6 is a fragment containing an active hydrogen reactive functional group, wherein the active hydrogen reactive functional group is selected from one or more of epoxy, hydroxyl, amino, and isocyanate groups, preferably selected from epoxy groups; and m is not 0, and preferably is an integer from 1 to 10.

[0104] Embodiment 10. A waterborne wood coating composition as described in any one of Embodiments 1 to 7, wherein the oligomeric siloxane further comprises two or more segments having at least one reactive hydrogen functional group.

[0105] Embodiment 11. The waterborne wood coating composition as described in Embodiment 10, wherein the oligomeric siloxane has a structure represented by general formula 2: (General Formula 2) R A This indicates a functional group that can be hydrolyzed to remove small molecules, wherein the functional group is selected from C1-C6 alkoxy, C2-C6 olefin, C6-C6 olefin, and C6-C6 olefin. 10 Aryloxy, C1-C6 alkyloxy, C6-C 10 Aromatic acyloxy, C1-C6 alkyl ketone oxime and C6-C 10 One or more of the aromatic ketoxime groups, preferably selected from C1-C6 alkoxy groups; and R B This refers to a segment containing an active hydrogen reactive functional group, wherein the active hydrogen reactive functional group is selected from one or more of epoxy, hydroxy, amino, and isocyanate groups, preferably selected from epoxy groups; and m is not 0, and preferably is an integer from 1 to 10.

[0106] Embodiment 12. The waterborne wood coating composition as described in any one of Embodiments 1 to 11, wherein the oligomeric siloxane is insoluble in water.

[0107] Embodiment 13. The waterborne wood coating composition as described in any one of Embodiments 1 to 12, wherein the oligomeric siloxane is present in an amount of 1 to 10 wt% relative to the total weight of the waterborne wood coating composition.

[0108] Implementation Method 14. A wood product comprising: A wood-based substrate having at least one main surface; and At least one paint film, said paint film being formed by a water-based wood coating composition of any one of embodiments 1 to 13, applied directly or indirectly to the main surface.

[0109] Embodiment 15. The wood product as described in Embodiment 14, wherein the wood substrate comprises hardwood, chestnut, oak, red chestnut, camellia, eucalyptus, Douglas fir, Japanese cedar, American cypress, Japanese red pine, Japanese cypress, water walnut, black walnut, maple, Japanese beech, Japanese paulownia, birch, sage, magnolia, ash, teak, oak, catalpa, camphorwood, cedar, oak, rubberwood, or combinations thereof.

[0110] Although the present invention has been described with reference to numerous embodiments and examples, those skilled in the art will recognize that other embodiments can be designed based on the disclosure of the present invention without departing from the scope and spirit of the invention.

Claims

1. A water-based wood coating composition comprising i) A water-based paint, wherein the water-based paint comprises an aqueous dispersion of polymer particles and optionally at least one additional additive, wherein the at least one additional additive comprises at least one pigment / filler, at least one cosolvent, at least one thickener, at least one leveling agent, at least one defoamer, or any combination thereof. ii) At least one oligomeric siloxane, said at least one oligomeric siloxane having one or more functional groups that can be hydrolyzed to remove small molecules. in, The paint film formed by the water-based wood coating composition has a gloss level of no more than 40 at a 60-degree angle.

2. The water-based wood coating composition as described in claim 1, wherein, The water-based wood coating composition contains virtually no matting agents.

3. The water-based wood coating composition as described in claim 1, wherein, The small molecule includes at least one alcohol, at least one carboxylic acid, at least one oxime, water, or a combination thereof.

4. The water-based wood coating composition as described in claim 1, wherein, The polymer particles have one or more active hydrogen functional groups.

5. The water-based wood coating composition as described in claim 1, wherein, The polymer particles have one or more active hydrogen functional groups selected from -COOH, -OH, -SH, secondary amino and primary amino groups or combinations thereof.

6. The water-based wood coating composition of claim 5, wherein, The one or more active hydrogen functional groups are carboxyl-functionalized.

7. The water-based wood coating composition of claim 1, wherein, The aqueous dispersion of the polymer particles includes aqueous dispersions of vinyl acetate polymer particles, aqueous dispersions of acrylic polymer particles, aqueous dispersions of organosilicon polymer particles, aqueous dispersions of polyurethane polymer particles, aqueous dispersions of polyurethane-polyacrylic polymer particles, aqueous dispersions of fluoropolymer polymer particles, or any combination thereof.

8. The waterborne wood coating composition of claim 1, wherein, The at least one oligomeric siloxane further comprises one or more segments having at least one reactive hydrogen functional group.

9. The waterborne wood coating composition of claim 1, wherein, The at least one oligomeric siloxane has a structure represented by general formula 1: (General Formula 1) in At least one of R1, R2, R3, R4, R5, and R6 is a functional group capable of hydrolyzing and removing small molecules, wherein the functional group is selected from C1-C6 alkoxy, C2-C6 alkenoxy, C6-C6 alkoxy, C2 ... 10 Aryloxy, C1-C6 alkyloxy, C6-C 10 Aromatic acyloxy, C1-C6 alkyl ketone oxime and C6-C 10 One or more of the aromatic ketoxime groups, preferably selected from C1-C6 alkoxy groups; and At least one of R1, R2, R3, R4, R5, and R6 is a fragment containing an active hydrogen reactive functional group, wherein the active hydrogen reactive functional group is selected from one or more of epoxy, hydroxyl, amino, and isocyanate groups, preferably selected from epoxy groups; and m is not 0, and preferably is an integer from 1 to 10.

10. The waterborne wood coating composition of claim 1, wherein, The oligomeric siloxane further comprises two or more segments having at least one reactive hydrogen functional group.

11. The waterborne wood coating composition of claim 10, wherein, The oligomeric siloxane has a structure represented by general formula 2: (Formula 2) R A This indicates a functional group that can be hydrolyzed to remove small molecules, wherein the functional group is selected from C1-C6 alkoxy, C2-C6 olefin, C6-C6 olefin, and C6-C6 olefin. 10 Aryloxy, C1-C6 alkyloxy, C6-C 10 Aromatic acyloxy, C1-C6 alkyl ketone oxime and C6-C 10 One or more of the aromatic ketoxime groups, preferably selected from C1-C6 alkoxy groups; and R B This refers to a segment containing an active hydrogen reactive functional group, wherein the active hydrogen reactive functional group is selected from one or more of epoxy, hydroxy, amino, and isocyanate groups, preferably selected from epoxy groups; and m is not 0, and preferably is an integer from 1 to 10.

12. The waterborne wood coating composition of claim 1, wherein, The oligomeric siloxane is insoluble in water.

13. The waterborne wood coating composition of claim 1, wherein, The oligomeric siloxane is present in an amount of 1 to 10 wt% relative to the total weight of the waterborne wood coating composition.

14. A wooden product comprising A wood-based substrate having at least one main surface; and At least one paint film, said paint film being formed by directly or indirectly applying the water-based wood coating composition of claim 1 to the main surface.

15. The wood product of claim 14, wherein the wood substrate comprises hardwood, chestnut, oak, red chestnut, camellia, euonymus, Douglas fir, Japanese cedar, American cypress, Japanese red pine, Japanese cypress, water walnut, black walnut, maple, Japanese beech, Japanese paulownia, birch, sage, magnolia, ash, teak, oak, catalpa, camphorwood, cedar, oak, rubberwood, or combinations thereof.

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