JP7703442B2 - Coating composition for wood and wood-based materials and uses thereof - Google Patents

Description

The present invention relates to a coating composition for wood and wood materials, which comprises an organosilane compound having an amino group, a boron compound, and an organic solvent of a specific composition, and has excellent applicability and permeability to wood and/or wood materials, a method for producing coated wood or wood materials using the same, and uses of the same.

Polymeric substances obtained by reacting organosilane compounds with boron compounds are able to combine the advantages of inorganic and organic materials; more specifically, they can be designed to have high hardness, crack prevention, transparency, heat resistance, chemical resistance, etc., as appropriate for the application, and are therefore used in a variety of applications, including coating agents, paints, adhesives, glass substrates, and fillers.

In particular, polymeric substances obtained by reacting an organosilane compound having an amino group with a specific boron compound have excellent properties, such as being able to be formed in a relatively short time without requiring complicated processes such as hydrolysis required in the sol-gel method, and being applicable to one-component room temperature curing materials.
As for coating agents, it has been reported that by further combining a metal alkoxide and lithium with the above-mentioned organosilane compound having an amino group and a specific boron compound, a coating film having good hard coat properties and good adhesion to metals can be obtained even when dried at room temperature and normal humidity, and that the coating can be used as a coating agent for metals, glass, ceramics, plastics, etc. (see, for example, Patent Document 1).

For wood and wood-based materials, there is a strong demand for coatings that can be cured at room temperature and have excellent hardness, etc., from the viewpoints of scratch prevention, waterproofing, stain resistance, etc. In the study of materials using the above-mentioned organosilane compounds and boron compounds having amino groups, application to wood has also been suggested (for example, see Patent Document 2).
However, no results have been reported of actual use in coatings for wood or wood-based materials, and therefore no reports have been published on formulations of compositions suitable for coatings for wood or wood-based materials or design guidelines therefor.
Furthermore, since wood and woody materials are porous, when applying a coating agent, the coating agent needs to have high permeability into wood and/or woody materials from the viewpoint of maintaining stain resistance and texture (particularly the texture of solid wood), etc. However, no coating agent that can be cured at room temperature and has excellent hardness and other properties, such as the above-mentioned coating composition based on an organosilane compound having an amino group and a specific boron compound, and that also has excellent permeability into wood and/or woody materials has been reported so far.

JP 2011-26473 A International Publication No. WO 2006/129695

In view of the strong demand for coatings for wood or wood materials with regard to the ability to penetrate into wood and/or wood materials from the standpoint of maintaining texture, particularly the texture of solid wood, and in view of the limitations of the prior art described above, the present invention aims to provide a coating composition that can be cured at room temperature and contains an organosilane compound having an amino group and a boron compound, which has excellent permeability into wood and/or wood materials while maintaining excellent properties such as high hardness.

As a result of intensive research, the present inventors have discovered that in a coating composition based on a material system combining an organosilane compound having an amino group with a specific boron compound, by controlling the content of an organic solvent of a specific composition, more specifically, a lower alcohol in the organic solvent, within a predetermined range, it is possible to significantly improve the permeability into wood and/or woody materials while maintaining the excellent properties of the material system, and have completed the present invention.
That is, the present invention provides:
[1]
(a) A silane compound containing an amino group represented by the following formula: R _4-n —Si—(OR′) _n
(wherein R represents an amino group-containing organic group, and when a plurality of R's are present, they may be the same or different from each other; R' represents a methyl group, an ethyl group, or a propyl group, and when a plurality of R's are present, they may be the same or different from each other; and n represents an integer selected from 1 to 3);
(b) at least one boron compound selected from the group consisting _{of H3BO3} and _B2O3 ; and (c) an organic solvent containing 10% by mass or more _of a lower alcohol;
The present invention relates to a coating composition for wood and wood-based materials, comprising:
It should be noted that the term "coating composition for wood and wood-based materials" as used herein is intended to be sufficient if it can be used for either coating for wood or coating for wood-based materials, and both coating compositions that can be used only for coating for wood and coating compositions that can be used only for coating for wood materials are included in the scope of the present invention.

Moreover, the following [2] to [12] are each a preferred aspect or embodiment of the present invention.
[2]
The coating composition for wood and woody materials according to [1], wherein the (c) organic solvent containing 10% by mass or more of a lower alcohol contains 30 to 90% by mass of a lower alcohol.
[3]
The coating composition for wood and wood-based materials according to [1] or [2], wherein the lower alcohol has 2 to 5 carbon atoms.
[4]
The coating composition for wood and wood-based materials according to any one of [1] to [3], wherein the (c) organic solvent containing 10% by mass or more of a lower alcohol further contains a glycol ether.
[5]
The coating composition for wood and wood-based materials according to any one of [1] to [4], wherein the component (a) and the component (b) are capable of forming a reaction product having a polymer structure.
[6]
The coating composition for wood and woody materials according to any one of [1] to [5], further comprising (d) a metal alkoxide (excluding those corresponding to the above component (a)).
[7]
The coating composition for wood and wood-based materials according to any one of [1] to [6], further comprising (e) a surfactant.
[8]
The coating composition for wood and wood-based materials according to [7], wherein the surfactant (e) contains at least one fluorine-based surfactant.
[9]
The coating composition for wood and wood-based materials according to any one of [1] to [8], further comprising (f) an epoxy resin.

[10]
A coating obtained by curing the coating composition for wood and wood-based materials according to any one of [1] to [9].
[11]
A coated wood or wood-based material comprising the coating according to [10] and wood and/or wood-based material.
[12]
The coated wood or wood material according to claim 11, wherein the wood and/or wood-based material comprises solid wood.
[13]
A method for producing a coated wood or wood material, comprising a step of applying the coating composition for wood and wood materials according to any one of [1] to [9] to wood or wood material.
[14]
The method for producing a coated wood or wood material according to [13], wherein the wood or wood material is solid wood.
[15]
[11] or [12]. [13] A coating material for furniture, building materials, stationery, tableware, or sporting goods comprising the coated wood or wood material according to [11] or [12].
[16]
A method for producing furniture, building materials, stationery, tableware, or sporting goods, comprising a step of producing coated wood or wood material by the method according to [13] or [14].

According to the present invention, there is provided a coating composition for wood and wood materials that can significantly improve the permeability of the coating composition into wood and/or wood materials while maintaining excellent properties such as high hardness, and a coated wood or wood material that has suitable properties based on an appropriate application amount is provided.
The coating composition has excellent properties such as high hardness derived from the polymeric substance obtained by reacting an organosilane compound with a boron compound, and can be applied in an appropriate amount based on high permeability, which is particularly important for wood and wood-based materials. Therefore, the coating composition can be particularly suitably used for coating wood components used in furniture, building materials, stationery, tableware, etc.

The present invention relates to a coating composition for wood and wood-based materials, which contains the following components (a), (b), and (c):
(a) A silane compound containing an amino group represented by the following formula: R _4-n —Si—(OR′) _n
(wherein R represents an amino group-containing organic group, and when a plurality of R's are present, they may be the same or different from each other; R' represents a methyl group, an ethyl group, or a propyl group, and when a plurality of R's are present, they may be the same or different from each other; and n represents an integer selected from 1 to 3);
(b) at least one boron compound selected from the group consisting _{of H3BO3} and _B2O3 ; and (c) an organic solvent containing 10% by mass or more of a lower alcohol _.

Therefore, the coating composition for wood and woody materials of the present invention is usually a composition in which the above-mentioned component (a) (silane compound containing an amino group) and component (b) (boron compound) are dissolved or dispersed in an organic solvent containing 10% by mass or more of (c) a lower alcohol. The coating layer for wood and woody materials obtained by curing the coating composition for wood and woody materials of the present invention usually contains a compound at least partly including a chemical structure obtained by reacting the above-mentioned components (a) and (b). In addition, the coating composition for wood and woody materials of the present invention may have partially reacted with components (a) and (b) even before curing, and therefore may partially contain a reaction product between components (a) and (b).
The chemical structure obtained by reacting the above-mentioned (a) component (silane compound containing an amino group) with the (b) component (boron compound) often forms a polymer structure. Typically, the (b) boron compound acts as a crosslinking agent via the amino group in the (a) silane compound containing an amino group, polymerizing these components to form a polymer structure having a constitutional unit derived from the (a) silane compound containing an amino group and a constitutional unit derived from the (b) boron compound.
That is, in the coating composition for wood and wood materials of this preferred embodiment, component (a) and component (b) are combined in such a way that a reaction product having a polymer structure can be formed, typically under conditions of 10 to 50° C. That is, the reaction product has a polymer structure having a structural unit derived from component (a) and a structural unit derived from component (b). In this polymer structure, the ratio of the structural unit derived from component (a) to the structural unit derived from component (b) is preferably at least 0.02 moles of the structural unit derived from component (b) per 1 mole of the structural unit derived from component (a).

In this embodiment, the polymer structure having the structural units derived from the component (a) and the structural units derived from the component (b) may have a structure modified with other components, such as the metal alkoxide (d) or the epoxy resin (f) described below. The reaction product may also have a structure other than the above, such as a structure in which the structural unit derived from the metal alkoxide of the component (d) is incorporated into a polymer structure having structural units derived from the component (a) and structural units derived from the component (b).

(a) Silane Compound Containing an Amino Group Component (a) is a silane compound containing an amino group having a specific structure represented by the following formula:
R _4-n -Si-(OR') _n
(In the formula, R represents an amino group-containing organic group, R' represents a methyl group, an ethyl group, or a propyl group, and n represents an integer selected from 1 to 3.)

Here, R represents an amino group-containing organic group, examples of which include, but are not limited to, monoaminomethyl, diaminomethyl, triaminomethyl, monoaminoethyl, diaminoethyl, triaminoethyl, monoaminopropyl, diaminopropyl, triaminopropyl, monoaminobutyl, diaminobutyl, triaminobutyl, and organic groups having an alkyl group or aryl group with a larger number of carbon atoms than these. γ-Aminopropyl and aminoethylaminopropyl are particularly preferred, and γ-aminopropyl is most preferred. When multiple Rs are present, they may be the same or different.

In component (a), R' represents a methyl group, an ethyl group, or a propyl group. Among these, a methyl group and an ethyl group are preferred. When there are multiple R's, they may be the same or different.

In the component (a), n represents an integer selected from 1 to 3. Of these, n is preferably 2 or 3, and n is particularly preferably 3.
That is, as the component (a), γ-aminopropyltriethoxysilane and N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane are particularly preferred.

(b) Boron compound Component (b) is at least one boron compound selected from the group consisting of H ₃ BO ₃ and B ₂ O _3. Component (b) is preferably H ₃ BO ₃ .

The amounts of component (a) and component (b) used in the reaction between the two components are preferably in a ratio of 0.02 moles or more of component (b) per mole of component (a), more preferably 0.02 moles to 8 moles of component (b) per mole of component (a), and even more preferably 0.02 moles to 5 moles of component (b) per mole of component (a).
By making the amount of the (b) component 0.02 moles or more per mole of the (a) component, problems such as an excessively long time required for solidification, insufficient solidification, etc. can be effectively prevented. Also, by making the amount of the (b) component 8 moles or less per mole of the (a) component, problems such as the (b) component remaining without dissolving in the (a) component can be effectively prevented.

The mixing conditions (temperature, mixing time, mixing method, etc.) when reacting (a) a silane compound containing an amino group with (b) a boron compound can be selected as appropriate. Under normal room temperature conditions, the mixture becomes a transparent, viscous liquid and solidifies within a few minutes to a few tens of minutes. The solidification time and the viscosity and rigidity of the resulting reaction product vary depending on the proportion of boron compound, so it is preferable to adjust these conditions as appropriate depending on the physical properties of the reaction product to be obtained and the intended use.

The boron compound (b) can be preferably used in the form of an alcohol solution of the boron compound dissolved in an alcohol having 1 to 7 carbon atoms. Examples of alcohol having 1 to 7 carbon atoms include methyl alcohol, ethyl alcohol, various propyl alcohols, various butyl alcohols, and glycerin, with methyl alcohol, ethyl alcohol, and isopropyl alcohol being preferred. By using this alcohol solution, the time required to dissolve component (b) in component (a) can be shortened. For ease of handling, it is preferable that the concentration of the boron compound in the alcohol is high.

It is preferable that the reaction product is a reaction product obtained by reacting components (a) and (b) without going through a process of hydrolysis by adding water. In this case, since the process of hydrolysis by adding water is not required, the reaction product can be produced without a complicated process such as sol-gel formation, and without a long time.

(c) Organic Solvent The coating composition for wood and woody materials of the present invention contains an organic solvent from the standpoints of reaction speed and uniformity, ease of coating application, and the like.
The organic solvent constituting the coating composition for wood and woody materials of the present invention has a specific composition, and more specifically, contains an organic solvent containing 10% by mass or more of (c) a lower alcohol. In the coating composition for wood and woody materials of the present invention, it is preferable that the above-mentioned (a) component (amino group-containing silane compound) and (b) component (boron compound) are dissolved or dispersed in an organic solvent containing 10% by mass or more of (c) a lower alcohol.
Here, "lower alcohol" means an alcohol having 5 or less carbon atoms. Preferred examples of lower alcohols include methanol, ethanol, isopropanol, normal propanol, and normal butanol. Among lower alcohols, those having 2 to 5 carbon atoms are preferred, and ethanol and normal propanol are particularly preferred.
Other than the lower alcohol, there is no particular limitation on the components constituting the organic solvent, and an organic solvent that is liquid at room temperature, can be mixed with the lower alcohol, and can dissolve or disperse the above components (a) and (b), as well as other components described below, if present, can be appropriately used. For example, glycol ethers, such as 3-methoxy-3-methyl-1-butanol, preferably glycol ethers having 6 or more carbon atoms, can be used. There is no particular limitation on the amount of glycol ether used, but when 3-methoxy-3-methyl-1-butanol is used, it may be mixed in an amount of 30 to 70% of the organic solvent (c).

From the viewpoint of realizing high permeability into wood and/or woody materials, the total proportion of lower alcohols in the organic solvent (c) is preferably 10 mass % or more, and particularly preferably 30 mass % or more.
(c) There is no particular upper limit to the proportion of the lower alcohol in the organic solvent, and the lower alcohol may account for 100% by mass. However, by appropriately mixing other solvents, the proportion of the lower alcohol can be, for example, 90% by mass or less, or 70% by mass or less in total.
For example, since the above-mentioned 3-methoxy-3-methyl-1-butanol has low volatility, by replacing a part of the lower alcohol with it, it is possible to improve workability, extend the pot life, reduce volatile substances released into the work environment, and the like.

The mechanism by which the permeability of a coating composition into wood and/or wood-based materials is improved when the proportion of lower alcohol in the organic solvent is 10% by mass or more is not entirely clear, but it is presumed to be somehow related to the low viscosity, low surface tension, etc. brought about by the lower alcohol.

The amount of the (c) organic solvent used is not particularly limited, and may be appropriately set while taking into consideration the reaction efficiency between each component, including the above-mentioned (a) and (b) components, the efficiency and workability in applying the coating, the quality of the resulting coating, and the like.
Assuming that coatings for wood and woody materials are generally used, the amount of (c) organic solvent used is preferably 30 to 90 mass %, more preferably 50 to 75 mass %, of the coating composition for wood and woody materials. Regardless of the amount used, by making the content of the lower alcohol in (c) organic solvent 10 mass % or more, the coating for wood and woody materials of the present invention has excellent penetration into wood and/or woody materials.

(d) Metal Alkoxide The coating composition for wood and woody materials of the present invention may preferably further contain (d) a metal alkoxide (excluding those corresponding to component (a)). In addition, the polymeric substance that can be formed by the reaction of the coating composition for wood and woody materials of this embodiment may have a structure in which the polymeric structure that is the reaction product of the above-mentioned components (a) and (b) is further modified with (d) a metal alkoxide.
That is, a metal alkoxide (component (d)) can be added during or after the reaction of components (a) and (b). By adding component (d), the content of metal salt in the obtained reaction product can be increased, and the mechanical properties, chemical properties, etc. can be further improved, and a viscous liquid state similar to that in the case where component (d) is not used can be obtained, so that the properties and physical properties of the coating can be appropriately adjusted according to the application.

Compounds that fall under the above component (a) (silane compounds that have a specific structure and contain an amino group) are excluded from the metal alkoxides of component (d). Other restrictions do not apply to the metal alkoxides of component (d), and compounds that are generally classified as metal alkoxides, i.e., compounds that have at least one metal atom and at least one alkoxy group, can be used as the metal alkoxides of component (d) as long as they do not fall under the above component (a).

Examples of the metal of the metal alkoxide of the component (d) include, but are not limited to, Si, Ta, Nb, Ti, Zr, Al, Ge, B, Na, Ga, Ce, V, Ta, P, Sb, etc. Preferred are Si, Ti, and Zr because of the ease of forming the alkoxide, and since the component (d) is preferably liquid, Si and Ti are particularly preferred. Examples of the alkoxide (alkoxy group) of the metal alkoxide of the component (d) include methoxy, ethoxy, propoxy, butoxy, and alkoxy groups having a carbon number of 2 or more. Methoxy, ethoxy, propoxy, and butoxy are preferred, and methoxy and ethoxy are more preferred. Particularly preferred examples of the component (d) include tetramethoxysilane and tetraethoxysilane.
The component (d) may be a polymer, and for example, a pentamer of tetraethoxysilane can be suitably used. A combination of a monomer and a pentamer can also be used.

There is no particular limit to the amount of component (d) used, and it can be set appropriately depending on the application and desired properties of the resulting coating, but it is preferable to use it in a ratio of 10 moles or less per mole of component (a). A ratio of 0.1 to 5 moles per mole of component (a) is more preferable. By using 0.1 moles or more of component (d) per mole of component (a), the effect of adding component (d) as described above can be fully exerted. Furthermore, by using 10 moles or less of component (d), the occurrence of cloudiness can be effectively suppressed.

(e) Surfactant A surfactant may be further added to the coating composition for wood and wood materials of the present invention for the purpose of improving wettability with the substrate and leveling. In addition, the use of a surfactant can further improve the permeability into wood and/or wood materials.
In the present invention, since the smoothness of the coating layer surface may decrease due to penetration into wood and/or wood-based materials, it is particularly beneficial to add a surfactant to improve the leveling properties. There are no particular limitations on the type of surfactant, and it can be appropriately selected depending on the application form of the coating, the affinity with other components, particularly the (c) organic solvent, and the like. The surfactant may be any of anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants.

From the viewpoint of improving leveling properties and penetration, it is particularly preferable to use a fluorine-based surfactant, a silicone-based surfactant, an alkyl ether-based surfactant, etc. Among them, it is preferable to use a fluorine-based surfactant from the viewpoint of improving penetration.
Specific examples of preferred fluorine-based surfactants include the "Surflon" series manufactured by AGC Seimi Chemical Co., Ltd., the "Megafac" series manufactured by DIC Corporation, and the "Ftergent" series manufactured by Neos Corporation.

There is no particular restriction on the amount of (e) surfactant added, and it can be appropriately set depending on the application form of the coating and the physical properties required after curing, etc.
Assuming that a coating for wood and wood-based materials is generally used, the amount of (e) surfactant used is preferably 0.01 to 5.0 mass %, and particularly preferably 0.1 to 1.0 mass %, of the coating composition for wood and wood-based materials.

Synthetic Resin The coating composition for wood and woody materials of the present invention can further contain a synthetic resin instead of or in addition to the (d) metal alkoxide. That is, a synthetic resin can be added during or after the reaction of the (a) component and the (b) component. By adding a synthetic resin, crack prevention properties can be imparted to the resulting coating, and the coating composition of the present invention can be used, for example, as a resin hard coat agent.

The synthetic resins that can be used in the present invention are not particularly limited, but examples include acrylic resins, epoxy resins, polyester resins, amino resins, urethane resins, and furan resins, and synthetic resins having various degrees of polymerization (molecular weights) can be used. Vinyl ester resins, epoxy acrylates, dipentaerythritol hexaacrylates, etc. can also be preferably used. Among these, it is preferable to use (f) epoxy resins from the viewpoints of resin properties such as strength, reactivity with other components, stability, etc.

(f) Epoxy Resin The coating composition for wood and woody materials of the present invention may contain (f) an epoxy resin in addition to the above components (a) to (c).
The epoxy resin (f) may be incorporated into the polymer structure composed of the components (a) and (b) during curing to form a part of the polymer structure, and may crosslink the polymer structure to change the chemical structure and physical properties of the reaction product of the components (a) and (b). By containing the epoxy resin (f) in this manner, the coating composition for wood and woody materials of this embodiment can affect the chemical structure and physical properties of the reaction product that constitutes the cured coating, thereby controlling the reactivity and mechanical properties of the coating.

The epoxy resin (f) that can be preferably used in this embodiment is not particularly limited, and any resin classified as an epoxy resin in the industry, that is, a thermosetting resin that can be cured by forming a crosslinked network with epoxy groups in the polymer structure, can be used, and epoxy resins having various degrees of polymerization (molecular weight) can be used. Among them, at least one epoxy resin selected from the group consisting of glycidyl ether type epoxy resins of bisphenol A or bisphenol F, hydrogenated bisphenol A type epoxy resins, glycidyl ester type epoxy resins, alicyclic epoxy resins, and polyglycol type epoxy resins can be preferably used.

There is no particular limitation on the amount of (f) epoxy resin added, and it can be set appropriately depending on the application form of the coating and the physical properties required after curing, etc.
Assuming that the coating for wood and wood-based materials is generally used, the amount of epoxy resin (f) used is preferably 1 to 30 g, and more preferably 4 to 10 g, per gram of component (a). In other words, if the amount of component (f) added is not too large, there is a tendency for the decrease in hardness to be suppressed, and conversely, if the amount is not too small, there is a tendency for chemical durability to be easily maintained.

Silicone oil The coating composition for wood and woody materials of the present invention can further contain silicone oil instead of the synthetic resin such as (d) metal alkoxide or (f) epoxy resin, or in addition to the synthetic resin such as (d) metal alkoxide or (f) epoxy resin. That is, during the reaction of the (a) component with the (b) component, or after the reaction, silicone oil can be added instead of or in addition to the (d) component. By adding silicone oil, the physical properties such as flexibility and hardness of the obtained coating can be appropriately adjusted.

Silicone oils used for the above purposes are polymeric substances having siloxane bonds and various degrees of polymerization (molecular weights), such as methylpolysiloxane and methylphenylsilicone, with dimethylpolysiloxane (dimethylsilicone) being preferred.

The amount of silicone oil used for the above purpose is preferably a ratio of 10 moles or less of the siloxane repeating units of the silicone oil per mole of component (a). A ratio of 0.1 to 5 moles is more preferable. When the number of siloxane repeating units is 0.1 moles or more per mole of component (a), the effect of adding silicone oil as described above is easily obtained, and when the number of siloxane repeating units is 5 moles or less, the effect on functionality due to the reaction product of components (a) and (b) is limited.

Other components In addition to the above components, the coating composition for wood and wood materials of the present invention may contain at least one component selected from the group consisting of corrosion inhibitors, inorganic nanoparticles, pigments, organic acids, and mixtures thereof. Examples of corrosion inhibitors include phosphoric acid, phosphorous acid, phosphonic acid, tannic acid, and mixtures thereof. The use of a corrosion inhibitor is also beneficial from the viewpoint of preventing corrosion of wood and/or wood materials.
The coating composition for wood and wood-based materials of the present invention can function as a paint by adding a color-developing component such as a pigment.

Wood and wood-based materials Wood and wood-based materials to which the coating composition for wood and wood-based materials of the present invention is applied are not particularly limited, and may be sawn wood (solid wood), processed wood made by processing wood chips or fibers, regenerated wood made by solidifying wood powder with resin, etc. Processed wood and regenerated wood may be any of plywood, laminated wood, laminated wood, particle board, MDF, etc.
The wood species is not particularly limited, and may be any one or a combination of two or more of various woods such as cypress, cedar, hiba, oak, paulownia, zelkova, sawara, etc. Furthermore, the part is not particularly limited, and the coating composition of the present invention can be applied to various parts such as straight grain, straight grain, sapwood, red wood, and cross grain.
The coating composition for wood and wood materials of the present invention has excellent permeability into wood and/or wood materials, and can therefore be used on compressed wood, which is generally difficult for coating agents to penetrate, and can achieve a remarkable technical effect of great practical value, namely, that a desired coating layer can be formed relatively easily on compressed wood.

By applying the coating composition for wood and wood materials of the present invention to wood or wood materials and curing it, a coating (layer) is formed on the wood or wood materials, and coated wood or wood materials can be produced. Heating is not essential for curing, but heating can shorten the curing time.
More specifically, the coating composition for wood and wood materials of the present invention can be applied to the surface of wood or wood materials by methods such as dipping, spray coating, roll coating, brush coating, etc. A coating (layer) may be formed by one application, or a coating (layer) may be formed by repeating two or more applications. When a coating (layer) is formed by repeating two or more applications, the coating composition may be cured after application and then further applied, or the coating may be repeated without curing, and the coating composition may be cured after all applications have been completed.
The amount of coating composition for wood and wood materials to be applied is not particularly limited, but is preferably 0.3 g to 10 g, more preferably 0.5 g to 2.0 g, and especially preferably 1.0 g or more ^per 100 ^cm2 of wood or wood material. An application amount of 0.3 g or more per 100 cm2 of wood or wood material indicates that the coating composition has high permeability into wood or wood material.

There is no particular limitation on the thickness of the coating (layer) after hardening, and it can be set appropriately depending on the purpose of the coating, the required physical properties, the manner in which the coated wood or wood material is used, etc., but it is preferably 5 μm or less, and particularly preferably 2 μm or less.
There is no particular restriction on the penetration depth of the coating layer into wood or wood-based materials, but from the viewpoint of the stability, adhesion, etc. of the coating (layer), it is preferably 10 to 300 μm, and particularly preferably 50 to 200 μm.

The coating composition for wood and wood materials of the present invention has high permeability compared to conventional techniques and can form a sufficient amount of coating layer on wood and/or wood materials, so that the coated wood or wood material of one embodiment of the present invention can be particularly suitable for use in applications where wood or wood materials are widely used from the standpoint of aesthetics, texture, etc., and protection by a coating is required, such as furniture, building materials, stationery, tableware, sporting goods, etc.

The present invention will now be described in further detail with reference to examples and comparative examples, but the present invention is not limited thereto in any way.

In the following Examples and Comparative Examples, the physical properties and characteristics were evaluated by the following methods.
Penetration (amount applied)
The coating composition obtained in each Example and Comparative Example was applied to a 10 x 10 x 1 cm MDF (medium density fiberboard) or solid wood so that no liquid pooled, and dried at room temperature for 24 hours. The same procedure was repeated the next day and the day after, for a total of three coatings and dryings.
The weight of the coated MDF board or solid wood after the third drying was measured, and the increase (g) from the initial weight was taken as the coating amount.
Penetrating magic
After the third drying, the coated surface of the coated MDF board or solid wood was arbitrarily marked with oil-based marker and wiped with ethanol. Those that could be wiped off without leaving any visible stains were rated as ◯ (pass).
Appearance (wood texture)
After the third drying, the coated surface of the coated MDF board or solid wood was visually inspected to determine the woody texture. Those that maintained the woody texture were rated as ◯ (pass), and those that lost the woody texture (whitening of the coating surface, etc.) were rated as × (fail).

Example 1
As the (a) component, 40 parts by mass of γ-aminopropyltriethoxysilane liquid was added as the (b) component, and 10 parts by mass of H ₃ BO ₃ powder was added as the (b) component. After stirring for 5 minutes, 70 parts by mass of tetraethoxysilane as the (d) component and 70 parts by mass of tetraethoxysilane pentamer as the (d) component were added. After stirring for another 5 minutes and leaving it, 20 parts by mass of bisphenol A resin (CY232 manufactured by Nagase Chemtec Corporation) as the (f) component, 420 parts by mass of methanol as the (c) component, and 2 parts by mass of SZ-1919 (silicone-based surfactant, manufactured by Toray Dow Corning Co., Ltd.) as the (e) component were added and mixed to prepare the coating composition of Example 1.
Using the obtained coating composition, a coating film was formed on an MDF board of 10 x 10 x 1 cm size according to the above-mentioned method, and the permeability (amount applied), penetration with a marker pen, and appearance (wood texture) were evaluated.
The results are shown in Table 1.

Example 2
The coating composition of Example 2 was prepared in the same manner as in Example 1, except that 420 parts by mass of ethanol was added as component (c) instead of methanol as component (c). A coating film was formed on an MDF board using the composition, and the permeability (amount applied), marker penetrability, and appearance (wood texture) were evaluated.
The results are shown in Table 1.

Example 3
The coating composition of Example 3 was prepared in the same manner as in Example 1, except that 420 parts by mass of normal propanol was added as component (c) instead of methanol as component (c). A coating film was formed on an MDF board using the composition, and the permeability (amount applied), marker penetrability, and appearance (wood texture) were evaluated.
The results are shown in Table 1.

Example 4
The coating composition of Example 4 was prepared in the same manner as in Example 1, except that 420 parts by mass of isopropanol was added as component (c) instead of methanol as component (c). A coating film was formed on an MDF board using the composition, and the permeability (amount applied), marker penetrability, and appearance (wood texture) were evaluated.
The results are shown in Table 1.

Example 5
The coating composition of Example 5 was prepared in the same manner as in Example 1, except that 420 parts by mass of normal butanol was added as component (c) instead of methanol as component (c). A coating film was formed on an MDF board using the composition, and the permeability (amount applied), marker penetrability, and appearance (wood texture) were evaluated.
The results are shown in Table 1.

(Comparative Example 1)
A coating composition of Comparative Example 1 was prepared in the same manner as in Example 1, except that 420 parts by mass of MMB (3-methoxy-3-methyl-1-butanol) was added instead of methanol as component (c). A coating film was formed on an MDF board using the composition, and the permeability (amount applied), marker penetrability, and appearance (wood texture) were evaluated.
The results are shown in Table 1.

Example 6
The coating composition of Example 6 was prepared in the same manner as in Example 1, except that 210 parts by mass of ethanol and 210 parts by mass of MMB were added as component (c) instead of methanol as component (c). A coating film was formed on an MDF board using the composition, and the permeability (amount applied), marker penetrability, and appearance (wood texture) were evaluated.
The results are shown in Table 1.

(Example 7)
The coating composition of Example 7 was prepared in the same manner as in Example 6, except that SZ-1919 was not added as the component (e). A coating film was formed on an MDF board using the composition, and the permeability (amount of application), marker penetrability, and appearance (wood texture) were evaluated.
The results are shown in Table 1.

(Example 8)
The coating composition of Example 8 was prepared in the same manner as in Example 6, except that 2 parts by mass of Surflon S-611 (a fluorochemical surfactant, manufactured by AGC Seimi Chemical Co., Ltd.) was added as component (e) instead of SZ-1919 as component (e). A coating film was formed on an MDF board using the composition, and the permeability (amount applied), marker penetration, and appearance (wood texture) were evaluated.
The results are shown in Table 1.

Example 9
The coating composition of Example 9 was prepared in the same manner as in Example 6, except that 2 parts by mass of Megafac F-559 (a fluorosurfactant manufactured by DIC Corporation) was added as component (e) instead of SZ-1919 as component (e). A coating film was formed on an MDF board using the composition, and the permeability (amount applied), marker penetration, and appearance (wood texture) were evaluated.
The results are shown in Table 1.

(Example 10)
The coating composition of Example 10 was prepared in the same manner as in Example 6, except that 2 parts by mass of Megafac F-563 (a fluorosurfactant manufactured by DIC Corporation) was added as component (e) instead of SZ-1919 as component (e). A coating film was formed on an MDF board using the composition, and the permeability (amount applied), marker penetration, and appearance (wood texture) were evaluated.
The results are shown in Table 1.

(Example 11)
The coating composition of Example 11 was prepared in the same manner as in Example 6, except that 2 parts by mass of TFS4440 (polyether-modified siloxane, manufactured by Momentive Performance Materials Inc.) was added as component (e) instead of SZ-1919 as component (e). A coating film was formed on an MDF board using the composition, and the permeability (amount of application), marker penetration, and appearance (wood texture) were evaluated.
The results are shown in Table 1.

Example 12
The coating composition of Example 12 was prepared in the same manner as in Example 6, except that 2 parts by mass of KP-431 (a silicone mixture, manufactured by Shin-Etsu Chemical Co., Ltd.) was added as component (e) instead of SZ-1919 as component (e). A coating film was formed on an MDF board using the composition, and the permeability (amount applied), marker penetrability, and appearance (wood texture) were evaluated.
The results are shown in Table 1.

Example 13
The coating composition of Example 13 was prepared in the same manner as in Example 6, except that 2 parts by mass of Emulgen 106 (polyoxyethylene lauryl ether, manufactured by Kao Corporation) was added as component (e) instead of SZ-1919 as component (e). A coating film was formed on an MDF board using the composition, and the permeability (amount applied), marker penetration, and appearance (wood texture) were evaluated.
The results are shown in Table 1.

(Example 14)
The coating composition of Example 14 was prepared in the same manner as in Example 6, except that the amount of SZ-1919 added as component (e) was changed to 8 parts by mass. A coating film was formed on an MDF board using the composition, and the permeability (amount applied), marker penetrability, and appearance (wood texture) were evaluated.
The results are shown in Table 1.

A comparison of Examples 1 to 5 with Comparative Example 1 shows that the use of lower alcohols improves the permeability of the coating composition into wood materials. A comparison of Examples 2, 6, and Comparative Example 1 shows that the permeability can be controlled by adjusting the content of lower alcohols. Furthermore, by referring to Examples 8 and onwards, it can be seen that the permeability can also be controlled (in many cases improved) by adding a surfactant, and that the permeability can be significantly improved by adding a fluorine-based surfactant in particular.

(Example 15)
The coating composition of Example 6 was used to form a coating film on Western Red Cedar (WRC) material in the same manner as in Example 6, except that WRC material was used instead of MDF board, and the permeability (amount applied), marker penetration, and appearance (wood texture) were evaluated.
The results are shown in Table 2.

(Example 16)
A coating film was formed on cypress wood in the same manner as in Example 6, except that the coating composition of Example 6 was used and cypress wood was used instead of an MDF board, and the permeability (amount applied), marker penetration, and appearance (wood texture) were evaluated.
The results are shown in Table 2.

(Example 17)
A coating film was formed on pine wood using the coating composition of Example 6 in the same manner as in Example 6, except that pine wood was used instead of an MDF board, and the permeability (amount applied), marker penetration, and appearance (wood texture) were evaluated.
The results are shown in Table 2.

(Example 18)
Using the coating composition of Example 6, a coating film was formed on cedar wood in the same manner as in Example 6, except that cedar wood was used instead of an MDF board, and the permeability (amount applied), marker penetration, and appearance (wood texture) were evaluated.
The results are shown in Table 2.

Example 19
Using the coating composition of Example 6, a coating film was formed on Ipe wood in the same manner as in Example 6, except that Ipe wood was used instead of MDF board, and the permeability (amount applied), marker penetration, and appearance (wood texture) were evaluated.
The results are shown in Table 2.

It is clear that the coating composition for wood and wood materials of the present invention is a suitable coating composition having excellent permeability, stain resistance, etc., even for various solid woods, which are typical types of wood.

The coating composition for wood and wood materials, and the coated wood or wood materials of the present invention can be applied in an appropriate amount based on appropriate penetration into wood and/or wood materials, while providing a coating that appropriately possesses high hardness, scratch resistance, waterproofing, stain resistance, etc., derived from the polymeric substance obtained by reacting an organosilane compound with a boron compound, and therefore has high applicability in various industrial fields such as architecture, construction, and furniture manufacturing.

Claims (14)

(a) A silane compound containing an amino group represented by the following formula: R _4-n —Si—(OR′) _n
(wherein R represents an amino group-containing organic group, and when a plurality of R's are present, they may be the same or different from each other; R' represents a methyl group, an ethyl group, or a propyl group, and when a plurality of R's are present, they may be the same or different from each other; and n represents an integer selected from 1 to 3);
(b) at least one boron compound selected from _the group consisting of _H3BO3 and _{B2O3 ;}
(c) an organic solvent containing 10% by mass or more of a lower alcohol ;
(d) metal alkoxides (excluding those falling under component (a) above); and
(f) epoxy resin;
A coating composition for wood and wood-based materials comprising:
The (d) metal alkoxide includes a combination of a monomer and a pentamer.
The coating composition for wood and wood-based materials . The coating composition for wood and wood-based materials according to claim 1, wherein the (c) organic solvent containing 10% by mass or more of a lower alcohol contains 30 to 90% by mass of a lower alcohol. The coating composition for wood and wood-based materials according to claim 1 or 2, wherein the lower alcohol has 2 to 5 carbon atoms. The coating composition for wood and wood-based materials according to any one of claims 1 to 3, wherein the organic solvent (c) containing 10% by mass or more of a lower alcohol further contains a glycol ether. A coating composition for wood and wood-based materials according to any one of claims 1 to 4, in which the components (a) and (b) are capable of forming a reaction product having a polymer structure. The coating composition for wood and wood-based materials according to claim 1 , further comprising (e) a surfactant. 7. The coating composition for wood and wood-based materials according to claim 6 , wherein the surfactant (e) contains at least one fluorosurfactant. A coating obtained by curing the coating composition for wood and wood-based materials according to any one of claims 1 to 7 . 9. Coated wood or wood-based material comprising a coating according to claim 8 and wood and/or wood-based material. 10. The coated wood or wood-based material of claim 9 , wherein the wood and/or wood-based material comprises solid wood. A method for producing a coated wood or wood material, comprising the step of applying the coating composition for wood or wood material according to any one of claims 1 to 7 to wood or wood material. The method for producing a coated wood or wood material according to claim 11 , wherein the wood or wood-based material is solid wood. 11. Furniture, building materials, stationery, tableware, or sporting goods, comprising the coated wood or wood material according to claim 9 or 10 . A method for producing furniture, building materials, stationery, tableware, or sporting goods, comprising a step of producing coated wood or wood-based material by the method according to claim 11 or 12 .