Sealer for wood products and product containing a sealer layer formed by the sealer

Abstract

The present invention relates to a wood seal primer and a product containing a seal primer layer formed by the seal primer. Specifically, the wood seal primer comprises: component A, the component A contains a water-dispersible isocyanate and a solvent, and the solid content of the component A is in the range of 60-100wt%.

Description

Technical Field

[0001] The invention relates to a sealing primer for woodware and a product containing a sealing primer layer formed by the sealing primer. The sealing primer layer is formed on the surface of a wooden substrate and can play a role in preventing rib expansion. Background Art

[0002] Wood products, including wooden furniture, are one of the most commonly used products in industry and life. They are mainly made of wood substrates with capillary porous structures on the surface. Before painting, in order to obtain a smooth surface, the wood substrate must usually be polished. However, this process inevitably leads to a large amount of loosely bound wood fibers left on the surface of the wood substrate. When water-based wood paint is applied to the treated substrate, water easily penetrates into the capillaries of the substrate, causing the capillaries to expand, resulting in the loosely bound fibers protruding to the polished surface, forming a coating with an uneven surface, which is called the "rib expansion" phenomenon. The existence of this phenomenon will significantly reduce the decorative effect of the coating.

[0003] At present, there are usually two methods to reduce or eliminate the "bulking" problem caused by water-based wood paint: 1) Use fast-drying water-based acrylic emulsion or water-based polyurethane dispersion as a film-forming resin to make paint, and use its fast-drying and good penetration characteristics to control the bulging and achieve a sealing effect. Due to the low solid content of the construction and the low degree of cross-linking of the paint film, the filling effect is general, the anti-bulking ability is limited, and the transparency of the overall paint film is affected. 2) Use water-soluble acrylic resin as a film-forming resin to make paint, and use the characteristics of its self-drying resin to control the bulging and achieve a sealing effect. The disadvantages are poor penetration; the anti-bulking effect on some easily shrinkable substrates is general; and the VOC exceeds the standard and the odor is strong.

[0004] Therefore, there is still a need in the wood coating industry to further improve the anti-"beam" coating of wood substrates. Summary of the invention

[0005] On one hand, the present invention discloses a wood sealing primer, which is a one-component coating composition, comprising: component A, wherein component A comprises a water-dispersible isocyanate and a solvent, and the solid content of component A is in the range of 60-100wt%, preferably in the range of 65-90wt%.

[0006] Still another aspect of the present invention discloses a wood sealing primer, which is a two-component coating composition, comprising: component A, wherein component A comprises a water-dispersible isocyanate and a solvent, wherein the solid content of component A is in the range of 60-100wt%, preferably in the range of 65-90wt%; and component B, wherein component B comprises hydroxyalkyl (meth)acrylate.

[0007] Still another aspect of the present invention provides an article comprising a wood substrate having at least one major surface; and a sealer primer layer formed by the wood sealer primer of the present invention directly coated on the major surface of the wood substrate.

[0008] In the present invention, the inventors innovatively use water-dispersible isocyanate as the main component of the blocking primer. The isocyanate group (NCO group) of the water-dispersible isocyanate can react with the hydroxyl group, carboxyl group, etc. in the wood to form a dense paint film on the surface of the wood, thereby forming a blocking coating on the wood to prevent rib expansion. In addition, the blocking primer for woodware containing component A according to the present invention has a high solid content, which can be directly applied on the main surface of the wooden substrate, and the resulting blocking primer layer has excellent anti-rib expansion effect and adhesion.

[0009] Surprisingly, the wood seal primer according to the present invention can further include a B component, and the B component is a small molecule (meth) hydroxyalkyl acrylate. In this case, the wood seal primer is a two-component coating composition, and the A component and the B component have very good compatibility and construction tolerance, and the dry film transparency is excellent. After the two are mixed, they have excellent water solubility, and equipment and tools can be directly cleaned with water, which has good environmental protection. Due to the excellent porosity and wettability of (meth) hydroxyalkyl acrylate, along with the A and B components on the wood surface and internal rapid reaction, the reaction crosslinking density is larger, forming a dense and tough crosslinked structure, the wood surface can be effectively fixed, and a significantly better anti-increase effect can be achieved, which is difficult to foresee before the present invention.

[0010] The inventors of the present invention have surprisingly found that the two-component wood sealing primer according to the present invention has the following advantages compared with the traditional water-based sealing primer:

[0011] (1) Excellent penetration and wettability: Due to the small molecular weight and small particle size of the water-soluble monomer, the wood sealing primer according to the present invention has excellent penetration and wettability on various wood substrates;

[0012] (2) Excellent anti-bulking property: Since the wood sealing primer according to the present invention has excellent penetration and wettability, as the A and B components react quickly on the surface and inside of the wood substrate, a dense and tough cross-linked structure is formed, which can effectively fix the surface of the wood substrate and prevent the bulging phenomenon;

[0013] (3) Excellent sealing property: When the wood sealing primer according to the present invention is a two-component coating composition, the reaction crosslinking density is large, and the isocyanate dry film itself has excellent oil sealing, water resistance, alcohol resistance and other properties, so the sealing effect is excellent;

[0014] (4) Excellent filling property: Since the construction solid content of the wood sealing primer according to the present invention is 40wt% to 60wt%, it has obvious advantages over the traditional water-based sealing primer (20wt% to 30wt%), and the dry film has better filling property;

[0015] (5) Due to the excellent permeability after film formation, the paint film has excellent color rendering effect, which has a very good effect on the display of substrate color or base color.

[0016] The details of one or more embodiments of the invention are set forth in the description which follows. Other features, objects, and advantages of the invention will become apparent from the description and claims.

[0017] definition

[0018] As used herein, without quantifiers, "at least one" and "one or more" are used interchangeably. Thus, for example, a composition comprising an additive can be interpreted to mean that the composition comprises "one or more" additives.

[0019] Where a composition is described as comprising or including specific components, it is contemplated that optional components not contemplated by the present invention are not excluded from the composition, and that the composition may consist of or be composed of the contemplated components; or where a method is described as comprising or including specific process steps, it is contemplated that optional process steps not contemplated by the present invention are not excluded from the method, and that the method may consist of or be composed of the contemplated process steps.

[0020] For simplicity, only some numerical ranges are explicitly disclosed herein. However, any lower limit can be combined with any upper limit to form an unambiguous range; and any lower limit can be combined with other lower limits to form an unambiguous range, and any upper limit can be combined with any other upper limit to form an unambiguous range. In addition, although not explicitly stated, each point or single value between the range endpoints is included in the range. Thus, each point or single value can be combined with any other point or single value as its own lower limit or upper limit or with other lower limits or upper limits to form an unambiguous range.

[0021] The term "film-forming resin" refers to a polymer compound that can form a continuous paint film or coating under certain conditions. It can be natural or synthetic, and can be physically formed by solvent volatilization or chemically formed by chemical cross-linking reaction. Among them, chemical film-forming film-forming resins are further divided into: resins that form films by reacting with curing agents, and self-cross-linking film-forming resins. Common film-forming resins include: phenolic resins, amino resins, alkyd resins, epoxy resins, polyester resins, acrylic resins, etc. In this article, the "water-dispersible isocyanate" used in the present invention is usually used as a curing agent in the field of coatings and does not belong to film-forming resins.

[0022] When used in the context of a wood substrate, the term "primary surface" is the surface formed by the length and width dimensions of the wood substrate for providing a decoration.

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

[0024] When used in reference to a "wood sealer," the term "application viscosity" refers to the viscosity at which the wood sealer can be applied without sagging or unapplicable application problems.

[0025] When used in relation to "wood sealer", the term "construction solid content" refers to the content of non-volatile matter contained in the wood sealer when it can be normally applied, usually measured after baking in a normal pressure oven at 150°C for 1 hour. Usually, during the construction process, if the mixture obtained by mixing the components of the wood sealer is too viscous, a diluent needs to be added to dilute it to meet the construction requirements. Therefore, the construction solid content is usually lower than the solid content of the wood sealer itself.

[0026] As used herein, the term "volatile organic compound (VOC)" refers to any carbon-containing compound that participates in atmospheric photochemical reactions, except carbon monoxide, carbon dioxide, carbonic acid, metal carbides or carbonates. Typically, volatile organic compounds have a vapor pressure of 0.1 mm Hg or higher. As used herein, "volatile organic compound content (VOC content)" refers to the weight of VOCs per volume of a composition or coating composition, for example reported as g / L.

[0027] When appearing in this description and claims, the terms "comprises" and "includes" and variations thereof do not have a limiting meaning.

[0028] The terms "preferred" and "preferably" refer to embodiments of the present invention that may provide certain benefits under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. In addition, the recitation of one or more preferred embodiments does not mean that other embodiments are not useful, and is not intended to exclude other embodiments from the scope of the present invention. DETAILED DESCRIPTION

[0029] In one aspect, an embodiment of the present invention discloses a closed primer for woodware, comprising:

[0030] The A component comprises a water-dispersible isocyanate and a solvent, and the solid content of the A component is in the range of 60-100 wt %.

[0031] The wood sealing primer of the embodiment of the present invention has a relatively high solid content. In some embodiments of the present invention, the solid content of component A is preferably in the range of 60-100wt%, more preferably in the range of 65-90wt%, still more preferably in the range of 65-85wt%, still more preferably in the range of 65-80wt%, and most preferably in the range of 65-75wt%.

[0032] The wood sealing primer containing component A according to the embodiment of the present invention has a high solid content and meets the VOC emission standard, and can be directly applied to the main surface of the wood substrate. The anti-swelling effect and adhesion of the obtained product are comparable to those of the oily anti-swelling sealing coating, and the VOC emission meets the environmental protection requirements.

[0033] Water dispersible isocyanate

[0034] The term "isocyanate" as used herein refers to a compound containing at least one isocyanate group (-NCO), which may be a small molecule compound or an oligomer. The term "polyisocyanate" refers to a compound containing at least two isocyanate groups (-NCO). The isocyanate groups are capable of chain extension and cross-linking reactions with active hydrogen polymers, thereby forming a three-dimensional network structure in the coating. Suitable isocyanates include aliphatic polyisocyanates, aromatic polyisocyanates, or any combination thereof. The term "aliphatic polyisocyanate" as used herein refers to a polyisocyanate compound in which an isocyanate group is directly connected to an aliphatic chain or ring. The term "aromatic polyisocyanate" as used herein refers to a polyisocyanate compound in which an isocyanate group is directly connected to an aromatic ring.

[0035] As examples of suitable polyisocyanate compounds, the present invention can use hexamethylene diisocyanate, dodecamethylene diisocyanate, cyclohexane-1,4-diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, cyclopentane-1,3-diisocyanate, p-phenylene diisocyanate, toluene-2,4-diisocyanate, naphthalene-1,4-diisocyanate, biphenyl-4,4'-diisocyanate, benzene-1,2,4-triisocyanate, xylene-1,4-diisocyanate, xylene-1,3-diisocyanate, diphenylmethane diisocyanate, butane-1,2,3-triisocyanate or polymethylene polyphenyl polyisocyanate.

[0036] As an example of a suitable isocyanate oligomer, a polyurethane prepolymer of any polyisocyanate compound listed above, a polyester prepolymer of any polyisocyanate compound listed above, or a polyether prepolymer of any polyisocyanate compound listed above and any combination thereof can be used. Polyurethane prepolymers (e.g., hexamethylene diisocyanate (HDI) trimer), polyester prepolymers, or polyether prepolymers can be made by any suitable method known to those of ordinary skill in the art. For example, a polyurethane prepolymer can be made by reacting a polyol monomer with one or more of a polyisocyanate compound under suitable conditions; a polyester prepolymer or a polyether prepolymer can be made by reacting a polyester polyol or a polyether polyol with one or more of a polyisocyanate compound under suitable conditions. Alternatively, any suitable commercial product can be used as a polyurethane prepolymer, a polyester prepolymer, or a polyether prepolymer. In one embodiment of the invention, the isocyanate includes a hexamethylene diisocyanate (HDI) trimer.

[0037] In certain embodiments of the present invention, the water-dispersible isocyanate is preferably a hydrophilic group-modified and / or at least partially hydrophilic group-modified isocyanate, more preferably a hydrophilic group-modified isocyanate.

[0038] In certain embodiments of the present invention, the hydrophilically modified isocyanate is non-ionic hydrophilically modified or ionic hydrophilically modified, preferably ionic hydrophilically modified.

[0039] In some embodiments of the present invention, the water-dispersible isocyanate is derived from the group consisting of 1,4-butane diisocyanate, 1,5-pentane diisocyanate, hexamethylene diisocyanate (HDI), 1,10-decane diisocyanate, cyclohexane-1,3-diisocyanate, cyclohexane-1,4-diisocyanate, 4,4'-dicyclohexylmethane diisocyanate (HMDI), cyclopentane-1,3-diisocyanate, isophorone diisocyanate (IPDI), dimers or trimers thereof, derivatives thereof, and any combination thereof, preferably derived from one or more of hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), dimers or trimers thereof.

[0040] Preferably, in the wood seal primer according to the present invention, the water-dispersible isocyanate used has one or more hydrophilic groups. In some embodiments of the present invention, the hydrophilic group can be in the form of an acid, such as a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, a phosphonic acid group, a phosphite group, etc. Additionally, considering the stability of the system, a portion of the hydrophilic group can be in the form of an acid salt, such as a neutralized acid or anhydride. Examples of suitable hydrophilic groups in the form of an acid salt include carboxylate (-CO2 - ), sulfate, phosphate, sulfonate, phosphite, phosphonate and combinations thereof. In a preferred embodiment of the present invention, the hydrophilic group comprises not only anionic hydrophilic groups in acid form, but also anionic hydrophilic groups in acid salt form. Preferably, the water-dispersible isocyanate contains a sulfonate group.

[0041] Further preferably, the water-dispersible isocyanate comprises at least one isocyanate group and at least one alkoxysilane group, such as a water-dispersible isocyanate as shown in the following formula:

[0042]

[0043] The water-dispersible isocyanate containing at least one isocyanate group and at least one alkoxysilane group is usually obtained by silane-modifying a commercially available isocyanate. For example, a commercially available sulfonic acid-modified isocyanate trimer is used for silane-modification, and an alkoxysilane is reacted with the sulfonic acid-modified isocyanate trimer under room temperature and stirring, so that at least a portion of -NCO in the sulfonic acid-modified isocyanate trimer reacts with the alkoxysilane. The use of an isocyanate containing an alkoxysilane group in the wood sealing primer of the present invention can help form a denser coating, thereby providing a more excellent sealing effect.

[0044] The wood blocking primer according to the invention contains a suitable solvent which is inert to isocyanate groups. Examples of suitable solvents are solvents for conventional coating compositions known per se, such as ethyl acetate, butyl acetate, ethylene glycol monomethyl or monoethyl ether acetate, 1-methoxy-2-propyl acetate, 3-methoxy-n-butyl acetate, acetone, 2-butanone, 4-methyl-2-pentanone, cyclohexanone, toluene, xylene, chlorobenzene, white spirits (for example in the form of solvent naphtha, (Deutsche EXXON CHEMICAL GmbH, Cologne, DE) and (Deutsche Shell Chemie GmbH, Eschborn, DE)), carbonates (such as dimethyl carbonate, diethyl carbonate, ethylene carbonate and propylene carbonate), lactones (such as β-propiolactone, γ-butyrolactone, ε-caprolactone and ε-methylcaprolactone), as well as propylene glycol diacetate, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, ethylene glycol butyl ether acetate, diethylene glycol butyl ether acetate, propylene glycol monomethyl ether acetate, 1,3-dioxolane, N-methylpyrrolidone and N-methylcaprolactam, or any mixture of such solvents.

[0045] Preferably, the solvent is selected from one or more of ethyl acetate, butyl acetate, xylene, toluene, propylene glycol monomethyl ether acetate, ethylene glycol butyl ether acetate, diethylene glycol butyl ether acetate, N-methylpyrrolidone, ethylene glycol monobutyl ether, acetone and butanone, preferably selected from one or more of xylene and propylene glycol monomethyl ether acetate.

[0046] The inventor innovatively used water-dispersible isocyanate as the main component of the sealing primer, and utilized the NCO group of the water-dispersible isocyanate to react with the hydroxyl group, carboxyl group, etc. in the wood to form a dense paint film on the surface of the wood, thereby forming an anti-rib expansion sealing layer on the wood.

[0047] In some embodiments of the present invention, in addition to component A, the wood seal primer further comprises component B, which comprises hydroxyalkyl (meth) acrylate. In this case, the wood seal primer is a two-component coating composition. Preferably, the hydroxyalkyl (meth) acrylate is a hydroxy C1-C20 alkyl (meth) acrylate. More preferably, the hydroxyalkyl (meth) acrylate is a water-soluble hydroxy C1-C20 alkyl (meth) acrylate. Examples of suitable hydroxy C1-C20 alkyl (meth) acrylates include, but are not limited to, hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate or any combination thereof. Preferably, hydroxyalkyl (meth) acrylate is selected from at least one of hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate, more preferably, selected from hydroxyethyl (meth) acrylate. Preferably, component B is hydroxyalkyl (meth) acrylate, more preferably hydroxy C1-C20 alkyl (meth) acrylate, and most preferably hydroxyethyl (meth) acrylate. In certain embodiments of the present invention, the solid content of component B is 100wt%.

[0048] In the case where the wood sealing primer is a two-component coating composition, the weight ratio of the A component to the B component is in the range of 1.5:1 to 3:1, preferably in the range of 2:1 to 3:1, and more preferably in the range of 2.5:1 to 3:1.

[0049] The inventors of the present invention have found that the two-component coating composition uses water-dispersible isocyanate as component A and (meth) hydroxyalkyl acrylate (water-soluble monomer) as component B, and the two have very good compatibility and construction tolerance, and the transparency of the dry film is excellent. After the two are mixed, they have excellent water solubility, and equipment and tools can be directly cleaned with water, so they have good environmental protection. In addition, when the weight ratio of the two meets the above range, the construction solid content of the wood sealing primer according to the present invention is between 40wt% and 60wt%, which has obvious advantages over traditional water-based sealing primers (the construction solid content range is usually 20wt% to 30wt%), and the dry film has better filling properties.

[0050] In certain embodiments according to the present invention, the wood sealer primer is substantially free of film-forming resin. The term "substantially free of" a certain compound means that the coating and / or composition of the present invention contains less than 5 wt% of the compound.

[0051] The wood sealer of the present invention may further include one or more fillers. The term "filler" used herein refers to any volume extender suitable for coatings, which may be organic or inorganic, for example, in the form of particles. There are no particular restrictions on the shape of the particles, which may have any appropriate shape. The average particle size of the filler may vary over a wide range, for example, in the range of about 10 nanometers to about 50 microns. Some fillers, in addition to serving as a volume extender for coatings, also impart one or more desired properties to the composition and / or the coating formed by the composition. For example, some fillers may impart the desired color to the composition and the coating obtained by the composition. In this case, this filler is also referred to as a "pigment". Some fillers may improve chemical and / or physical properties, particularly the mechanical properties of the coating obtained by the composition. In this case, this filler is also referred to as a "reinforcing filler".

[0052] The wood ware sealing primer of the present invention can also optionally further comprise the additional additive commonly used in the wood ware sealing primer, and these additives will not adversely affect the coating composition or the cured coating obtained therefrom. Suitable additives include, for example, those reagents that can improve the processing properties or manufacturing performance of the coating composition, enhance the aesthetic feeling of the composition or improve the specific functional properties or characteristics (such as adhesion to substrate) of the coating composition or the cured coating obtained therefrom. The additive that can be included is, for example, a carrier, an emulsifier, a pigment, an anti-migration aid, an antibacterial agent, a chain extender, a lubricant, a wetting agent, a biocide, a plasticizer, a defoamer, a colorant, a wax, an antioxidant, an anticorrosive, a flow control agent, a thixotropic agent, a dispersant, an adhesion promoter, a UV stabilizer, a thickener, a defoamer, a pH adjusting agent, a silane coupling agent, a high boiling point film-forming aid or a combination thereof. The content of each optional component is enough to play its intention to achieve the purpose, but preferably, such content will not adversely affect the coating composition or the cured coating obtained therefrom.

[0053] In one embodiment of the present invention, the two-component wood sealer comprises, relative to the total weight of the wood sealer, 25-40 wt% of the A component; 60-75 wt% of the B component; and 0-15 wt% of additional additives.

[0054] In one embodiment of the present invention, the two-component wood sealing primer still has a construction solid content of 40 to 60 wt % when the construction viscosity reaches 30 s or less.

[0055] In a preferred embodiment of the present invention, the two-component wood sealing primer has a construction solid content of 40 to 60 wt % when the construction viscosity reaches 30 s or less and simultaneously has a volatile organic compound (VOC) content of 600 g / L or less.

[0056] According to the present invention, the preparation of the one-component wood sealer can be achieved by any appropriate method known to those skilled in the art. For example, the wood sealer can be prepared by adding all components to a container and then stirring the resulting mixture until it is uniform. Alternatively, the wood sealer can be prepared by mixing some components first and then adding the remaining components to form a uniform mixture.

[0057] According to the present invention, the two-component wood sealing primer can be prepared by simply mixing the A component and the B component in a predetermined weight ratio in a mixing device before application.

[0058] According to the present invention, the wood sealer can be applied by conventional coating methods known to those skilled in the art. The coating methods include dipping, spin coating, spraying, curtain coating, brushing, roller coating and other coating methods known in the art. In one embodiment of the present invention, the wood sealer is applied by spraying. The wood sealer can be applied to various wet film thicknesses. In an embodiment of the present invention, the coating amount of the wood sealer is 30-100 g / m 2 In the range of 50-90 g / m 2 In the range of 60-80 g / m 2 The applied coating can be cured by air drying or by accelerating the curing using various drying devices (e.g., ovens) familiar to those skilled in the art.

[0059] In the present invention, the wood sealer can be used as it is, applied to a substrate to form a coating, preferably in direct contact with the substrate as a primer layer. Therefore, the present invention also relates to an article, which comprises (a) a wooden substrate having at least one main surface; (b) a sealer layer formed by the wood sealer of the present invention, which is applied on the main surface of the wooden substrate.

[0060] In goods according to the present invention, one or more coatings formed by water-based coating compositions may be applied on the surface of the seal primer layer. According to the present invention, the coating may include primer coating, intermediate coating, topcoat coating or a combination thereof. The coating may be directly applied to the seal primer layer, in direct contact with the seal primer layer. In some embodiments of the present invention, one or more colorant layers may be present between the coating formed by the water-based coating composition and the seal primer layer, thereby obtaining the desired color.

[0061] According to the present invention, two or more coating layers formed of an aqueous coating composition can be coated on the sealing primer layer, preferably three or more coating layers formed of an aqueous coating composition can be coated, and more preferably 4 or more coating layers formed of an aqueous coating composition can be coated without affecting the barrier effect of the sealing primer layer.

[0062] Still another aspect of the present invention provides an article comprising (a) a wooden substrate having at least one major surface; (b) a sealer primer layer formed by the wood sealer primer of the present invention directly coated on the major surface of the wooden substrate; and (c) a coating formed by an aqueous coating composition coated on the sealer primer layer.

[0063] As a wood substrate for making the article of the present invention, any suitable wood substrate known in the art can be used. According to the present invention, the wood substrate has at least one, preferably two, main surfaces opposite to each other. When used herein, "main surface" is a surface formed by the length and width dimensions of the wood substrate for decoration.

[0064] Preferably, the main surface of the wooden substrate may have polar groups such as hydroxyl, amino, thiol, etc., so that when the woodware sealing primer of the present invention is applied thereto, the water-dispersible isocyanate in the coating composition can easily wet the surface, thereby forming a coating on the substrate surface. Methods for obtaining a main surface with hydroxyl groups on the wooden substrate are known in the art. Specifically, hydroxyl groups can be introduced on the surface of the wooden substrate by surface treatment of the main surface of the wooden substrate, such as oxidation by corona treatment.

[0065] According to the present invention, the wooden substrate comprises softwood or hardwood or a combination thereof. As examples of softwood, pine, fir or cypress can be used. As examples of hardwood, ash, basswood, elm, maple, birch, alder, beech, oak, cherry, walnut or redwood can be used. In one embodiment of the present invention, a solid black gold board is used as the wooden substrate.

[0066] According to the present invention, the wood sealer can be applied by conventional coating methods known to those of ordinary skill in the art. The coating methods include dip coating, spin coating, spray coating, curtain coating, brush coating, roller coating, and other coating methods known in the art. In one embodiment of the present invention, the coating is performed using a spraying process.

[0067] According to the present invention, the article can be prepared, for example, by the following steps: (1) providing a polished wooden substrate; (2) applying the wood sealer of the present invention to the wooden substrate by a spraying process to form a sealer layer; (3) applying one or more desired coatings formed of an aqueous coating composition on the sealer layer in sequence by a wet-to-dry coating process. Optionally, a colorant can be applied to the sealer layer before step (3) to provide the wooden substrate with a desired color.

[0068] According to the present invention, the articles thus obtained can be used in the following applications, including, but not limited to: household furniture, such as tables, chairs, cabinets, etc.; bedroom and bathroom furniture; office furniture; custom furniture, such as school and children's furniture, hospital furniture, restaurant and hotel furniture, kitchen cabinets and furniture; panels for interior design; indoor and outdoor windows and doors; indoor and outdoor window frames and door frames; outdoor and indoor wainscoting and wood flooring.

[0069] The following examples more specifically describe the disclosure of the present invention, which are intended for illustrative purposes only, as various modifications and variations within the scope of the disclosure of the present invention are apparent to those skilled in the art. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are by weight, and all reagents used in the examples are commercially available and can be used directly without further treatment.

[0070] Example

[0071] Test Method

[0072] transparency : The coating compositions were formed into films under the same substrate and process conditions, and the transparency of each coating was compared visually and evaluated according to three levels: "high", "average" and "poor".

[0073] Adhesion : Determined by the cross-cut method according to ASTM D3359 standard, and evaluated according to three levels: "good", "average" and "poor".

[0074] Solid content : The amount of remaining components measured after the sample was baked in an atmospheric oven at 150°C for 1 hour to determine the solid content.

[0075] Construction solid content : Use a certain amount of water or solvent to dilute the sample to be tested to obtain the sample to be tested for construction, and then measure the sample to be tested for construction according to the test method for testing solid content.

[0076] Construction viscosity: As needed, use a certain amount of water or solvent to dilute the sample to be tested, and then use Iwata 4# cup to test its viscosity.

[0077] VOC Content : Measured according to standard HJ2537-2014.

[0078] Construction :Based on whether the spray gun is blocked during spraying, the atomization effect, the wetting effect and leveling after spraying, manual judgment is made and the evaluation is carried out according to three levels: "good", "average" and "poor".

[0079] Treating wood substrates

[0080] The ebony wood boards purchased from the timber market were kiln dried. Samples with a size of 15 cm*15 cm*1.5 cm were cut from the dried boards and placed under conditions of 25°C, 60% relative humidity (RH) and 1.8 m / s air flow to a constant weight, wherein the equilibrium moisture content of the sample was 11%. A strip sander was used to grind the sample through a 3M T The samples were sanded with Utility Cloth Sheet 180 grit sandpaper and cleaned with an air pressure gun.

[0081] Material

[0082] The raw materials used in each example are listed in Table 1 below.

[0083] Table 1

[0084]

[0085] Example 1-8: One-component wood sealer primer

[0086] To formulate the one-component wood sealer of the present invention, a water-dispersible isocyanate is mixed with an optional solvent to form the wood sealer of the present invention.

[0087] Then, the wood sealing primer of the present invention was sprayed on the treated sample and dried in air for 15 minutes, in an oven at 40° C. for 1 hour, and then cooled in air for 30 minutes, and then the anti-beading effect was determined by visual inspection.

[0088] In Example 8, a self-made water-dispersible isocyanate containing at least one alkoxysilane group is used, and the chemical structure is shown below. The preparation of the self-made water-dispersible isocyanate is as follows: Under room temperature and stirring conditions, di(3-trimethoxysilylpropyl)amine and a commercially available sulfonic acid-modified isocyanate trimer (trade name Bayhydur XP2655) are silane-modified at a molar ratio of 2:1 to obtain a silane-modified isocyanate.

[0089]

[0090] Table 2 below summarizes the composition and anti-rib expansion effect of the one-component wood sealing primer of the present invention.

[0091] Table 2

[0092]

[0093] As can be seen from the results in Table 2, the inventors pioneered the use of water-dispersible isocyanate as the main component of the sealing primer, without using a film-forming resin component. The isocyanate group of the water-dispersible isocyanate can react with the hydroxyl group, carboxyl group, etc. in the wood to form a dense paint film on the surface of the wood, thereby forming a closed coating on the wood to prevent rib expansion. In addition, although the one-component wood sealing primer according to the present invention has a high solid content, it can be directly sprayed on the main surface of the wooden substrate, and the resulting sealing primer layer has excellent anti-rib expansion effect and adhesion.

[0094] Examples 9-10: Two-component wood sealer primer

[0095] The wood sealer according to the present invention may further comprise a B component, wherein the B component is a hydroxyalkyl (meth)acrylate. In this case, the wood sealer is a two-component coating composition.

[0096] In order to study the effect of component B on the wood sealing primer of the present invention, different low molecular weight alcohols and hydroxyalkyl (meth)acrylates were used in combination with component A, i.e., water-dispersible isocyanate, according to the components shown in Table 3, and the obtained two-component coating composition was tested for construction solid content, miscibility, VOC content, construction viscosity, and coating amount. The coating was then dried at 50° C. for 1 hour, and the surface dry time, press dry time, and film forming property were tested. The results are shown in Table 3:

[0097] Table 3

[0098]

[0099] After testing, it was found that low molecular weight alcohol reacts too quickly with IPDI type hydrophilic modified aliphatic isocyanate, easily produces a large number of bubbles, and has film-forming problems. Therefore, it cannot be used in the wood-use closed primer according to the present invention. Water-soluble hydroxyethyl methacrylate and hydroxypropyl methacrylate have good compatibility with IPDI type hydrophilic modified aliphatic isocyanate, so the resulting paint film has excellent performance. Hydroxybutyl methacrylate is relatively large in molecular weight, insoluble in water, and has poor compatibility and water washing properties, so it is not suitable for this application.

[0100] In order to further study the effect of different proportions of component A and component B on the wood sealer primer of the present invention, hydroxyethyl methacrylate and Bayhydur 401-70 were added to a mixing container in different proportions as shown in Table 4 and mixed, and then stirred at 800-1000 rpm until uniform, thereby forming a sample to be tested. The workability and film-forming properties of the sample to be tested were tested, and the results are as follows:

[0101] Table 4:

[0102]

[0103] Therefore, when the wood sealing primer is a two-component coating composition, a relatively good construction effect can be achieved when the weight ratio of component A to component B is in the range of 1.5:1 to 3:1.

[0104] In order to further verify the anti-rib expansion effect of the wood sealing primer of the present invention, according to the following construction parameters, the two-component wood sealing primer of Example 9 of the present invention and conventional water-based sealing products WK8000B and WK1000B were respectively applied on the ebony wood substrate to form a primer coating, thereby forming a sample to be tested.

[0105] Table 5 below summarizes the composition, construction parameters and test results of the two-component wood sealing primer of the present invention and the water-based sealing product for comparison.

[0106] Table 5

[0107]

[0108]

[0109] It can be seen from the results in Table 5 that the construction solid content of the two-component wood sealing primer according to the present invention is between 40wt% and 60wt%, which has obvious advantages over the traditional water-based sealing primer (20wt% to 30wt%). In addition, the dry film has excellent penetration and excellent anti-rib expansion effect, and the permeability after film formation is excellent.

[0110] coating

[0111] The two-component wood sealing primer according to the present invention prepared according to the above Example 9, WK8000B from Guangdong Huarun Paint Co., Ltd. and WK1000B from Guangdong Huarun Paint Co., Ltd. were diluted with DPM or water according to the following Table 6, and the diluted mixture was applied on the surface of the ebony wood substrate as the first sealing primer, and then the universal water-based two-component primer WTD8500 was applied as the second primer and the universal water-based two-component topcoat WT85033 was applied as the third primer. The construction parameters of the first primer are shown in Table 3 above, and the test results of the entire coating are summarized in Table 6.

[0112] Table 6

[0113]

[0114] It can be seen from the test results in Table 6 that the two-component wood sealing primer according to the present invention has a higher crosslinking density, can achieve excellent anti-beading and sealing effects, and has excellent compatibility with conventional water-based two-component primers and topcoats, thereby further improving the transparency of the overall paint film. In addition, the obtained paint film has excellent color effects and has a very good effect on the development of the substrate color or the base color.

[0115] Although the invention has been described with reference to a number of embodiments and examples, a person skilled in the art, based on the present disclosure, will recognize that other embodiments can be designed without departing from the scope and spirit of the invention.

Claims

1. A closed primer for wood, comprising: A component, wherein the A component comprises a water-dispersible isocyanate, and the solid content of the A component is in the range of 60-100 wt %; and A B component comprising a hydroxyalkyl (meth)acrylate; in, The hydroxyalkyl (meth)acrylate is a water-soluble hydroxyalkyl (meth)acrylate, and the hydroxyalkyl (meth)acrylate is selected from one or more of hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxyethyl acrylate and hydroxypropyl acrylate; and Wherein, the wood sealing primer substantially does not contain film-forming resin.

2. The wood sealing primer according to claim 1, wherein: The solid content of the A component is in the range of 65-90wt%.

3. The wood sealing primer according to claim 1, wherein: The water-dispersible isocyanate is derived from the group consisting of 1,4-butane diisocyanate, 1,5-pentane diisocyanate, hexamethylene diisocyanate (HDI), 1,10-decane diisocyanate, cyclohexane-1,3-diisocyanate, cyclohexane-1,4-diisocyanate, 4,4'-dicyclohexylmethane diisocyanate (HMDI), cyclopentane-1,3-diisocyanate, isophorone diisocyanate (IPDI), dimers or trimers thereof, derivatives thereof, and any combination thereof.

4. The wood sealing primer according to claim 1, wherein: The water-dispersible isocyanate is derived from one or more of hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), dimers or trimers thereof.

5. The wood sealing primer according to claim 1, wherein: The water-dispersible isocyanate contains sulfonate groups.

6. The wood sealing primer according to claim 1, wherein: The water-dispersible isocyanate contains alkoxysilane groups.

7. The wood sealing primer according to any one of claims 1 to 6, wherein: The weight ratio of the A component to the B component is in the range of 1.5:1 to 3:

1.

8. The wood sealing primer according to any one of claims 1 to 6, wherein: The construction solid content of the wood sealing primer is at least 40wt%.

9. An article comprising: a wood substrate having at least one major surface; and A sealer primer layer, wherein the sealer primer layer is formed by coating the main surface with the sealer primer for wood according to any one of claims 1 to 8.

10. The article according to claim 9, wherein The coating amount of the wood sealing primer is 30-100 g / m 2 within the range.

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