JP5130791B2 - Water-based paint composition for wood and antifouling treated wood using the same - Google Patents

Description

  The present invention relates to an aqueous coating composition for wood containing an organic component and an inorganic component, and an antifouling-treated wood excellent in antifouling property and the like, which retains the texture of wood obtained using the same.

  Wooden building materials for interior use are broadly divided into painted and unpainted products. Painted products have a uniform color tone and can be given abrasion resistance, contamination resistance, chemical resistance, and the like by a protective layer of a paint film. Especially in flooring applications, since the base material is flat and easy to coat, and the surface can be protected by a coating film, the surface material of the material can be reduced to about 0.3 mm, which greatly reduces costs. Have been supplied in large quantities as painted composite flooring. As such a woodworking paint for a coated product, for example, a mixture of a fluororesin water dispersion and a pigment has been proposed (for example, see Patent Document 1). However, in order to leave the grain, it is necessary to adjust the blending ratio of the pigment, and it is difficult to obtain a high design property without impairing the unevenness characteristic of wood.

  Woody material has a pore structure and absorbs contaminants and diffuses into the material. Therefore, in the case of an unpainted product, maintenance such as providing a protective layer with a wax for solid (unpainted) building material after construction and periodically repainting the protective layer is necessary. Even if maintenance is performed, it is difficult to remove contaminants once they break through the protective layer and penetrate and diffuse inside the substrate. As a result, it has been supplied for high-end homes due to the high total cost.

  However, with the diversification of tastes, it is required to provide interior materials that leave the visual and tactile feel of wooden materials for general housing. Therefore, in order to increase the types of materials that can be used, to supply cheaper products, and to simplify maintenance, while maintaining the visual and tactile texture of wood, There is a demand for processing technology that suppresses the absorption and diffusion of contaminants to the surface, leaving no unremovable contamination marks.

  On the other hand, in the field of coating materials and the like, there is an increasing need to simultaneously realize handling properties such as flexibility and moldability and durability such as hardness, heat resistance, and weather resistance. Various organic-inorganic composite coating films have been proposed (for example, see Patent Document 2). The water-based coating composition proposed in Patent Document 2 is a composition containing a water admixture of an organic compound having a hydroxyl group, a polyalkoxysilane, and a catalyst, and is a transparent, uniform, hard and water-resistant organic-inorganic composite coating film Therefore, if it can be applied to wood, it is considered possible to impart water resistance while leaving the grain. However, the composition has poor storage stability because the hydrolysis and condensation reaction of the polyalkoxysilane continues to proceed during storage, and the resulting coating film has a level that satisfies the pencil hardness (about 2H to 6H). However, it does not exhibit sufficient wear resistance. Furthermore, since it is a curing reaction using a curing agent such as an aminoplast resin, coating with a thin film is difficult, and a high temperature of 100 ° C. or higher is required. Since it can cause deformation of itself, it cannot be deployed in wood applications.

JP 2004-137445 A JP-A-8-319457

  In view of the above circumstances, the problem to be solved by the present invention is wood that does not leave a contamination mark that cannot be removed by suppressing the absorption and diffusion of contaminants into the interior, without impairing the texture and grain peculiar to wood. Another object of the present invention is to provide a water-based paint composition for use and an antifouling treated wood obtained using the same.

In order to solve the above-mentioned problems, the present inventors have conducted intensive studies. As a result, by performing a sol-gel reaction of a metal alkoxide in the presence of a cationic resin having a specific structural unit , It was found that a composite of an organic component and an inorganic component can be achieved on a scale, and that the wood having the above performance can be obtained by forming it on the wood, and the present invention has been completed.

That is, the present invention comprises an aqueous dispersion of a cationic resin (A) having a structural unit represented by the following general formula (I), a metal alkoxide or a condensate thereof (B), and an acid catalyst (C). It is intended to provide an aqueous paint composition for wood characterized by containing. Furthermore, the present invention is obtained by applying an aqueous coating composition for wood containing an aqueous dispersion of a cationic resin, a metal alkoxide or a condensate thereof, and an acid catalyst onto wood and drying it. The antifouling treated wood is provided.

(In the formula (I), R ₁ Is an alkylene chain optionally containing an aliphatic cyclic structure, a residue of a dihydric phenol, or a polyoxyalkylene chain, and R ₂ And R ₃ Are alkyl groups which may contain an aliphatic cyclic structure independently of each other, and R ₄ Is a hydrogen atom or a residue of a quaternizing agent introduced by a quaternization reaction, and X- is an anionic counter ion. )

  ADVANTAGE OF THE INVENTION According to this invention, the water-based coating composition for wood containing the organic component and inorganic component with favorable storage stability can be provided. Treated wood obtained by using the water-based paint composition for wood has a high balance of wear resistance, water resistance, and antifouling properties, but does not impair the unevenness and grain characteristic of wood. It can be suitably used for applications that require luxury orientation.

The aqueous coating composition for wood according to the present invention contains an aqueous dispersion of a cationic resin (A) having a specific structural unit, a metal alkoxide or a condensate thereof (B), and an acid catalyst (C). It is characterized by.

  Recent studies have shown that many diatom and sponge creatures in nature (so-called biosilica) protect their cells with a composite membrane of silica and organic matter. In particular, in the composite membrane of biosilica, it was suggested that the function of the membrane is expressed by combining silica with a cationic polymer or a cationic protein (WEGG Muller Ed., Silicon). Biomineralization: Biology-Biotechnology-Molecular Biology-Biotechnology, 2003, Springer). Although the function of the cationic polymer or the cationic protein has not been fully elucidated yet, basically, the catalytic effect in the silica condensation, the induction of the spatial dimension in the silica sol formation and sol fusion (that is, to form a hybrid membrane with a fixed shape) It is considered to have an adhesive effect between a polymer and silica in forming a nano-level hybrid structure.

  In creating organic-inorganic composite coatings, the design concept based on an understanding of the mechanism of biosilica is considered to be extremely important. In particular, many cationic proteins complexed with biosilica have the characteristic of being insoluble in water even if they have a hydrophilic surface. The present inventors paid attention to this point, and devised to associate it with resin particles having a cationic surface. That is, in the present invention, by using an aqueous dispersion of the cationic resin (A) as the cationic polymer, a sol of the metal alkoxide or its condensate (B) by the acid catalyst (C) in the presence of the cationic resin. -It has been found that by performing a gel reaction, fine particles made of a cationic resin as an organic component and a metal oxide matrix obtained from a metal alkoxide or a condensate thereof as an inorganic component can be highly complexed. It is based on that.

  In the aqueous coating composition for wood of the present invention, the initial hydrolysis of the metal alkoxide or its condensate (B) is promoted by the acid catalyst (C), but the subsequent condensation reaction is suppressed by the cationic resin (A). The entire system is governed by ionic interactions between the hydroxy groups on the surface of the metal sol and the cations on the surface of the resin fine particles of the cationic resin (A) aqueous dispersion. As a result, the growth of the sol stops at a certain size, the anion sol is concentrated on the surface of the fine particles of the cationic resin (A) aqueous dispersion, and an aqueous dispersion having good stability can be obtained. By coating this aqueous dispersion, a gelled film having a metal oxide as a continuous phase is formed. In the continuous phase, the resin fine particles made of the cationic resin (A) are not aggregated, and each particle is individually agglomerated. It is possible to obtain a coating film having a nano-order repeating structure that is uniformly dispersed and compounded. In the coating film thus obtained, the combined effect of the organic component and the inorganic component is maximized, and the coating film properties such as wear resistance, water resistance and stain resistance are greatly improved. Such a structure and the effect derived from the structure cannot be obtained by using an aqueous anionic resin dispersion or an aqueous nonionic resin dispersion.

Hereinafter, materials used in the present invention will be described in detail.
[Cationic resin (A)]
The cationic resin (A) used in the present invention is an organic compound having a cationic functional group, and forms an aqueous dispersion that is stably dispersed in an aqueous medium. The aqueous medium is not particularly limited as long as it is a homogeneous solvent system mainly containing water. Examples of such solvent systems include a solvent system in which an alcohol-based water-soluble organic solvent such as methanol, ethanol, isopropanol, and butanol is mixed with water, and an ether-based water-soluble organic solvent such as tetrahydrofuran and butyl cellosolve in water. And the solvent system used. The most preferred aqueous medium is an isopropanol / water mixed solvent system. The amount of the water-soluble organic solvent added is preferably 50% by mass or less, particularly 20% by mass or less, based on the amount of water contained in the whole wood-based water-based coating composition. It is preferable to make it.

  The cationic resin (A) is dispersed in an aqueous medium, and the average particle size of the dispersed resin particles combines the stain resistance, abrasion resistance, and transparency of the resulting composite coating film. From the point to do, it is preferable that it is 0.005 micrometer-1 micrometer, More preferably, it is 0.01-0.4 micrometer.

  Examples of the cationic functional group include primary to tertiary amino groups and phosphino groups such as hydrochloric acid, nitric acid, acetic acid, sulfuric acid, propionic acid, butyric acid, (meth) acrylic acid, and maleic acid. And the like, quaternary ammonium groups, quaternary phosphonium groups, and the like.

  The content of the cationic functional group is not particularly limited as long as the cationic resin (A) does not dissolve in an aqueous medium and can form a stable dispersion. Therefore, the content of the preferred cationic functional group varies depending on the structure other than the cationic functional group such as the molecular weight and the degree of branching of the cationic resin (A). Usually, the cationic resin (A) If the solid content contains 0.01 to 1 equivalent / kg as a cation equivalent, an aqueous dispersion can be obtained. In particular, the dispersibility of the cationic resin (A) in an aqueous medium and the resulting coating film can be obtained. From the point which is excellent in balance with water resistance, it is preferable to contain 0.02-0.8 equivalent / kg, and it is especially preferable to contain 0.03-0.6 equivalent / kg.

  As the number average molecular weight (Mn) obtained by gel permeation chromatography (GPC) of the cationic resin (A) in terms of polystyrene, the cationic resin (A) is a stable dispersion without being dissolved in the aqueous medium. If it is the range which can form, it will not specifically limit, Usually, it is the range of 1,000-5,000,000, Preferably, it is the range of 5,000-1,000,000.

It is a cationic resin (A), the can be used urethane resins.

The urethane resin, ease of manufacture, a viewpoint RaYoshimi suitable that the affinity of the goodness of the later-described metal oxide (B '). The this urethane resin, the following cationic urethane resin (A-1), referred to.

  The cationic urethane resin (A-1) is a urethane resin having a cationic functional group, which is composed of a polyisocyanate, a polyol, and a chain extender used in combination as necessary.

  Examples of the polyisocyanate that can be used as the raw material for the cationic urethane resin (A-1) include organic polyisocyanates such as chain aliphatic polyisocyanates, cyclic aliphatic polyisocyanates, aromatic polyisocyanates, and aromatic aliphatic polyisocyanates. Various things, such as polyisocyanate obtained from an isocyanate and an amino acid derivative, can be illustrated.

  Specific examples of the chain aliphatic polyisocyanate include methylene diisocyanate, isopropylene diisocyanate, butane-1,4-diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexa Examples include methylene diisocyanate and dimer acid diisocyanate in which a carboxyl group of dimer acid is replaced with an isocyanate group.

  Specific examples of the cycloaliphatic polyisocyanate include cyclohexane-1,4-diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, 1,3-di (isocyanatemethyl) cyclohexane, methylcyclohexane diisocyanate, and the like. .

  Specific examples of the aromatic polyisocyanate include dialkyldiphenylmethane diisocyanate such as 4,4′-diphenyldimethylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate such as 4,4′-diphenyltetramethylmethane diisocyanate, 1,5-naphthylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 4,4′-dibenzyl isocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, etc. .

  Specific examples of the araliphatic polyisocyanate include xylylene diisocyanate and m-tetramethylxylylene diisocyanate. Specific examples of polyisocyanates obtained from amino acid derivatives include lysine diisocyanate.

  Examples of the polyol that can be used as a raw material of the cationic urethane resin (A-1) include various compounds having two or more hydroxy groups in one molecule, and the resulting organic-inorganic composite coating film is flexible. From the viewpoint of excellent properties, it is preferable to use a polymer polyol. Examples of the polymer polyol include polyether polyols such as polymers or copolymers such as ethylene oxide, propylene oxide, isobutylene oxide, and tetrahydrofuran; ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1 , 3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, octanediol, 1, Various saturated or unsaturated low molecular weight glycols such as 4-butynediol and dipropylene glycol, or alkyl glycidyl ethers such as n-butyl glycidyl ether and 2-ethylhexyl glycidyl ether, glycated versatic acid Monocarboxylic acid glycidyl esters such as ester, adipic acid, maleic acid, fumaric acid, phthalic anhydride, isophthalic acid, terephthalic acid, succinic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, azelaic acid, sebacic acid Polyester polyols obtained by dehydration condensation of dibasic acids such as suberic acid or acid anhydrides or dimer acids corresponding thereto; polyester polyols obtained by ring-opening polymerization of cyclic ester compounds; other polycarbonate polyols Polyolefin diols such as polybutadiene diol, polyisoprene diol, polychloroprene diol, polybutadiene glycol hydride, polyisoprene glycol hydride, and the like obtained by adding ethylene oxide or propylene oxide to bisphenol A In the presence of a chain transfer agent having one chain transfer group such as two or more hydroxy groups and mercapto groups, various radically polymerizable unsaturated monomers such as alkyl (meth) acrylates are polymerized. Examples thereof include macromonomers such as acrylic polymers, polyalkoxysilanes such as polydimethylsiloxane, castor oil polyol, chlorinated polypropylene polyol, and the like.

  The method for producing an aqueous dispersion of the cationic urethane resin (A-1) that can be used in the present invention using the above-described polyisocyanate and polyol is not particularly limited. As a method for introducing a functional group into the main chain of the urethane resin (A-1), for example, as described in JP-A No. 2002-307811, the polyisocyanate, the polyol, and a tertiary amino acid in the molecule are used. A urethane resin is synthesized using a chain extender having a group, a tertiary amino group in the resin is neutralized or quaternized with an acid, and then dispersed in an aqueous medium, or JP-A-2001-64346 As described above, a urethane resin is synthesized by reacting the polyisocyanate, the polyol, and a polyamine compound having primary and secondary amino groups, And a method of dispersing in an aqueous medium or the like to neutralize the secondary amine in the lipid.

  Further, the resin having a cationic functional group contained in the cationic urethane resin (A-1) in a portion (side chain) branched with respect to the longest bond length of the resin is the cationic functional group. Since the degree of freedom is large, it is possible to easily form an association structure with an aqueous medium necessary for obtaining an aqueous dispersion, and a more stable aqueous dispersion can be obtained. It is suitable in the present invention from the point that an anionic sol produced by the sol-gel reaction of the condensate (B) can be efficiently concentrated on the resin particle surface, and a wood-based aqueous coating composition having better storage stability can be obtained. Can be used.

The cationic resin (A) used in the present invention is a cationic urethane resin containing a structural unit represented by the following general formula (I), which is a cationic urethane resin having a cationic functional group in the side chain. a) is used .

(In the formula (I), R ₁ Is an alkylene chain optionally containing an aliphatic cyclic structure, a residue of a dihydric phenol, or a polyoxyalkylene chain, and R ₂ And R ₃ Are alkyl groups which may contain an aliphatic cyclic structure independently of each other, and R ₄ Is a hydrogen atom or a residue of a quaternizing agent introduced by a quaternization reaction, and X- is an anionic counter ion. )

  The production method of the cationic urethane resin (a) having the structural unit is not particularly limited, but as a production method using an industrially easily available and inexpensive raw material, the following general formula [IV] A tertiary amino group-containing polyol obtained by reacting a compound (a-1) having two epoxy groups in one molecule and a secondary amine (a-2) shown in FIG. The method of letting go is the most useful.

（式［ＩＶ］中、Ｒ１は、脂肪族環式構造を含んでいてもよいアルキレン鎖、２価フェノール類の残基、又はポリオキシアルキレン鎖を表す。）

(In the formula [IV], R1 represents an alkylene chain which may contain an aliphatic cyclic structure, a residue of a dihydric phenol, or a polyoxyalkylene chain.)

  As the compound (a-1) having two epoxy groups in one molecule, for example, the following compounds can be used alone or in combination of two or more.

Examples of those in which R ₁ in the general formula [IV] is an alkylene chain which may contain an aliphatic cyclic structure include ethanediol-1,2-diglycidyl ether, propanediol-1,2 -Diglycidyl ether, propanediol-1,3-diglycidyl ether, butanediol-1,4-diglycidyl ether, pentanediol-1,5-diglycidyl ether, 3-methyl-pentanediol-1,5-di Glycidyl ether, neopentyl glycol-diglycidyl ether, hexanediol-1,6-diglycidyl ether, polybutadiene glycol-diglycidyl ether, cyclohexanediol-1,4-diglycidyl ether, 2,2-bis (4-hydroxycyclohexyl) ) -Propane (hydrogenated bisphenol Examples thereof include diglycidyl ether of diol A), diglycidyl ether of hydrogenated dihydroxydiphenylmethane isomer mixture (hydrogenated bisphenol F), and the like.

Examples of R ₁ in the general formula [IV] that is a residue of a dihydric phenol include resorcinol-diglycidyl ether, hydroquinone-diglycidyl ether, 2,2-bis (4-hydroxy Phenyl) -propane (bisphenol A) diglycidyl ether, dihydroxydiphenylmethane isomer mixture (bisphenol F), diglycidyl ether, 4,4-dihydroxy-3-3'-dimethyldiphenylpropane diglycidyl ether, 4,4 Diglycidyl ether of dihydroxydiphenylcyclohexane, diglycidyl ether of 4,4-dihydroxydiphenyl, diglycidyl ether of 4,4-dihydroxydibenzophenone, diglycidyl ether of bis (4-hydroxyphenyl) -1,1-ethane Terbis, diglycidyl ether of bis (4-hydroxyphenyl) -1,1-isobutane, diglycidyl ether of bis (4-hydroxy-3-tert-butylphenyl) -2,2-propane, bis (2-hydroxynaphthyl) ) Diglycidyl ether of methane, diglycidyl ether of bis (4-hydroxyphenyl) sulfone (bisphenol S), and the like.

Moreover, as what R < ₁ > in the said general formula [IV] is a polyoxyalkylene chain, the number of repeating units of diethylene glycol-diglycidyl ether, dipropylene glycol-diglycidyl ether, and oxyalkylene is 3-60, for example. Polyoxyalkylene glycol-diglycidyl ethers such as polyoxyethylene glycol-diglycidyl ether and polyoxypropylene glycol-diglycidyl ether, diglycidyl ether of ethylene oxide-propylene oxide copolymer, polyoxytetraethylene glycol-di A glycidyl ether etc. can be mentioned.

Among these, since the water dispersibility of the resulting cationic urethane resin (a) can be further improved, R _{1 in} the above general formula [IV] is a polyoxyalkylene glycol diglycidyl which is a polyoxyalkylene chain. Ethers, particularly polyoxyethylene glycol-diglycidyl ether, polyoxypropylene glycol-diglycidyl ether, and diglycidyl ether of ethylene oxide-propylene oxide copolymer are preferred.

The epoxy equivalent of the diglycidyl ether of polyoxyalkylene glycol in which R _{1 in the} general formula [IV] is a polyoxyalkylene chain is preferable in that the cation concentration in the cationic urethane resin (a) can be designed over a wide range. Is 1000 g / equivalent or less, more preferably 500 g / equivalent or less, particularly preferably 300 g / equivalent or less.

  Although various compounds can be used as the secondary amine (a-2), a branched or straight chain aliphatic secondary amine is preferable from the viewpoint of easy reaction control.

  Examples of the secondary amine (a-2) include dimethylamine, diethylamine, di-n-propylamine, diisopropylamine, di-n-butylamine, di-tert-butylamine, di-sec-butylamine, di-n. -Pentylamine, di-n-peptylamine, di-n-octylamine, diisooctylamine, dinonylamine, diisononylamine, di-n-decylamine, di-n-undecylamine, di-n-dodecylamine, di- Examples include n-pentadecylamine, di-n-octadecylamine, di-n-nonadecylamine, and di-n-eicosylamine.

  Among these, it is difficult to volatilize when producing a tertiary amino group-containing polyol, or a part or all of the contained tertiary amino group is neutralized with an acid or quaternized with a quaternizing agent. In particular, an aliphatic secondary amine having 2 to 18 carbon atoms is preferable, and an aliphatic secondary amine having 3 to 8 carbon atoms is more preferable because steric hindrance can be reduced.

  The reaction between the compound (a-1) having two epoxy groups in one molecule and the secondary amine (a-2) is an equivalent ratio [NH group / epoxy group] of the epoxy group and NH group, preferably 0. 0.5 / 1 to 1.1 / 1, more preferably 0.9 / 1 to 1/1, and can be easily carried out at room temperature or under heating without catalyst. . At this time, an organic solvent may be used as necessary.

The reaction temperature is preferably in the range of room temperature to 160 ° C, more preferably in the range of 60 to 120 ° C. Although reaction time is not specifically limited, Usually, it is the range of 30 minutes-14 hours. The end point of the reaction can be confirmed by the disappearance of the absorption peak near 842 cm ⁻¹ due to the epoxy group by infrared spectroscopy (IR method).

  The tertiary amino group-containing polyol obtained by the above reaction is reacted with the polyisocyanate after neutralizing a part or all of the tertiary amino group previously contained with an acid or quaternizing with a quaternizing agent. Alternatively, it may be reacted with polyisocyanate to obtain a polyurethane resin, and then a cationic urethane resin (a) may be obtained by neutralization or quaternization of a tertiary amino group. Furthermore, the step of making the aqueous dispersion may be either during or after the synthesis of the urethane resin, and is selected depending on the type and amount of the chain extender that is an active hydrogen-containing compound such as polyamine used as necessary. can do.

  Examples of the acid that can be used for neutralizing a part or all of the tertiary amino group include formic acid, acetic acid, propionic acid, succinic acid, glutaric acid, butyric acid, lactic acid, malic acid, and citric acid. , Organic acids such as tartaric acid, malonic acid, adipic acid, organic sulfonic acids such as sulfonic acid, paratoluenesulfonic acid, methanesulfonic acid, and hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, boric acid, phosphorous acid, hydrofluoric acid Inorganic acids such as can be used. These acids may be used alone or in combination of two or more.

  Examples of the quaternizing agent that can be used for quaternizing a part or all of the tertiary amino group include dialkyl sulfates such as dimethyl sulfate and diethyl sulfate, methyl chloride, and ethyl chloride. Alkyl halides such as benzyl chloride, methyl bromide, ethyl bromide, benzyl bromide, methyl iodide, ethyl iodide, benzyl iodide, and alkyl or aryl sulfonates such as methyl methanesulfonate and methyl paratoluenesulfonate Epoxy such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, allyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, and phenyl glycidyl ether Etc. can be used like, they may be used in combination well 2 or more types may be used alone.

  The amount of acid or quaternizing agent used for neutralization or quaternization of the tertiary amino group is not particularly limited, but in order to express the excellent dispersion stability of the obtained cationic polyurethane resin (a). The amount is preferably in the range of 0.1 to 3 equivalents and more preferably in the range of 0.3 to 2.0 equivalents with respect to 1 equivalent of the tertiary amino group.

  Furthermore, in order to further improve the water resistance of the resulting coating film, it is preferable to introduce a structural unit containing a silanol group into the cationic urethane resin (a). When a structural unit containing a silanol group is introduced, from particles composed of a cationic urethane resin (a), which is an organic component, and an inorganic metal oxide (B ′) formed from a metal alkoxide or a condensate (B) thereof. Since a cross-linked structure is formed with the resulting matrix, a stronger coating film can be obtained, and the treated wood surface after coating is excellent in wear resistance.

  As a structural unit containing a silanol group, the structural unit represented by the following general formula [II] can be illustrated.

（式［ＩＩ］中、Ｒ５は水素原子、アルキル基、アリール基又はアラルキル基であり、Ｒ６はハロゲン原子、アルコキシル基、アシルオキシ基、フェノキシ基、イミノオキシ基又はアルケニルオキシ基であり、ｎは０、１又は２である。）

(In the formula [II], R5 is a hydrogen atom, an alkyl group, an aryl group or an aralkyl group, R6 is a halogen atom, an alkoxyl group, an acyloxy group, a phenoxy group, an iminooxy group or an alkenyloxy group, and n is 0, 1 or 2)

  In order to introduce the structural unit represented by the general formula [II] into the cationic urethane resin (a), it is preferable to use a silanol group-containing compound represented by the following general formula [III].

（式［ＩＩＩ］中、Ｒ５は水素原子、アルキル基、アリール基又はアラルキル基であり、Ｒ６はハロゲン原子、アルコキシル基、アシルオキシ基、フェノキシ基、イミノオキシ基又はアルケニルオキシ基であり、ｎは０、１又は２であり、Ｙは活性水素基を少なくとも１個以上含有する有機残基である。）

(In the formula [III], R5 is a hydrogen atom, an alkyl group, an aryl group or an aralkyl group, R6 is a halogen atom, an alkoxyl group, an acyloxy group, a phenoxy group, an iminooxy group or an alkenyloxy group, and n is 0, 1 or 2 and Y is an organic residue containing at least one active hydrogen group.)

  As the compound represented by the general formula [III], those in which Y in the general formula is an amino group or a mercapto group are easily available, and for example, γ- (2-aminoethyl) aminopropyltrimethoxysilane. , Γ- (2-hydroxylethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropyltriethoxysilane, γ- (2-hydroxylethyl) aminopropyltriethoxysilane, γ- (2-aminoethyl) ) Aminopropylmethyldimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldiethoxysilane, γ- (2-hydroxylethyl) aminopropylmethyldimethoxysilane, γ- (2-hydroxylethyl) aminopropylmethyldiethoxysilane Or γ- (N, N-di-2-hydroxyl ether L) Aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane or γ- (N-phenyl) aminopropyl Examples include trimethoxysilane, γ-mercaptopropyltrimethoxysilane, and γ-mercaptophenyltrimethoxysilane.

  The amount of these silanol group-containing compounds used is a wood having a water-resistant coating film in which a metal oxide (B ′) described later and a cationic urethane resin (a) are more strongly combined. Is obtained, the structural unit represented by the general formula [II] is contained in the range of 0.1 to 20% by mass with respect to the finally obtained cationic urethane resin (a). It is preferable to use together so that it may be used, and it is more preferable to use so that it may contain in 0.5-10 mass%.

  By using these silanol group-containing compounds in combination with the above-mentioned tertiary amino group-containing polyol and polyisocyanate, silanol groups can be introduced into the resulting cationic urethane resin (a).

  The cationic urethane resin (a) can be synthesized by reacting the above-mentioned tertiary amino group-containing polyol, polyisocyanate, and the silanol group-containing compound used in combination as necessary. Other polyols described above can also be used in combination.

  The reaction can be produced without a catalyst, but various catalysts such as stannous octylate, dibutyltin dilaurate, dibutyltin dimaleate, dibutyltin diphthalate, dibutyltin dimethoxide, dibutyltin diacetylacetate, dibutyl Tin compounds such as tin diversate, titanate compounds such as tetrabutyl titanate, tetraisopropyl titanate and triethanolamine titanate, tertiary amines, quaternary ammonium salts and the like may be used.

  The organic solvent contained in the aqueous dispersion of the cationic urethane resin (a) obtained as described above is preferably removed, for example, by a method such as distillation under reduced pressure during or after the reaction.

  The cationic urethane resin (A-1) used in the present invention may have a reactive functional group such as a hydroxy group, a carboxyl group, and an epoxy group as long as the dispersion stability of the resin is not inhibited. In addition, the cationic urethane resin (A-1) may have a nonionic hydrophilic group such as a polyethylene oxide chain or a polyamide chain in the molecule in order to improve dispersion stability. Furthermore, in order to obtain a stable aqueous dispersion, an emulsifier may be used in combination.

[Metal alkoxide (B)]
Preferred examples of the metal in the metal alkoxide or its condensate (B) used in the present invention include silicon, titanium, and aluminum.

  The silicon alkoxide or its condensate is not particularly limited as long as it is an alkoxysilane generally used in a sol-gel reaction. For example, tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, tetrabutoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltributoxy Silane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, isopropyltrimethoxysilane, isopropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-glycid Xylpropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane , Phenyltrimethoxysilane, phenyltriethoxysilane, 3,4-epoxycyclohexylethyltrimethoxysilane, trialkoxysilanes such as 3,4-epoxycyclohexylethyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diethyl Examples include dimethoxysilane, diethyldiethoxysilane, and partial condensates thereof.

  Examples of the titanium alkoxide include titanium isopropoxide, titanium lactate, and titanium triethanolamate. Examples of the aluminum alkoxide include aluminum isopropoxide.

  Among these, it is preferable to use silicon alkoxide or a condensate thereof from the viewpoint of industrial availability. Of these, tetramethoxysilane and its condensate are most preferred. Moreover, by using together the alkoxysilane which has a functional group which reacts with the cationic functional group in the cationic resin (A), the cross-linking of the coating film can be made more precise, and the coating film properties such as water resistance can be improved. It can also be improved. Most preferred in this case is 3-glycidoxypropyltrimethoxysilane.

  When the tetramethoxysilane and its condensate and 3-glycidoxypropyltrimethoxysilane are used in combination, the mass ratio after complete hydrolysis and condensation of each (after the complete hydrolysis of tetramethoxysilane and its condensate) (Mass) / (mass after complete hydrolysis of 3-glycidoxypropyltrimethoxysilane) is preferably in the range of 60/40 to 90/10, particularly in the range of 70/30 to 80/20. Is particularly preferred.

  Moreover, the ratio of the mass of the cationic resin (A) to the mass (B1) after hydrolysis condensation of the metal alkoxide or its condensate (B) is a mass ratio represented by (A) / (B1). The range is preferably 10/90 to 70/30, more preferably 20/80 to 70/30, and still more preferably 30/70 to 70/30. The hydrolysis reaction formula of metal alkoxide is as follows.

〔式中、Ｒ^１は有機基であり、Ｒ^２はアルキル基であり、Ｘは（ｍ＋ｎ）価の金属原子である。〕

[Wherein, R ¹ is an organic group, R ² is an alkyl group, and X is a (m + n) -valent metal atom. ]

  Therefore, the mass (B1) of the metal alkoxide after complete hydrolysis condensation is calculated by (charge amount) / (formula amount of metal alkoxide before hydrolysis reaction) × (formula amount of metal alkoxide after hydrolysis reaction). be able to.

[Acid catalyst (C)]
As the acid catalyst (C) used in the present invention, various acid catalysts can be used. For example, inorganic acids such as hydrochloric acid, boric acid, sulfuric acid, hydrofluoric acid, and phosphoric acid, and organic acids such as acetic acid, phthalic acid, maleic acid, fumaric acid, and paratoluenesulfonic acid can be used. These acids may be used alone or in combination of two or more. Among these, it is easy to adjust to the target pH range, the storage stability of the obtained water-based coating composition for wood is good, and the water resistance of the resulting antifouling treated wood is excellent. It is preferable to use an acid.

  Further, the pH of the solution after adding the acid catalyst (C) to the aqueous dispersion of the cationic resin (A) is less likely to cause problems such as corrosion of the machine due to the acid, and the obtained aqueous paint composition for wood From the point that the storage stability of the product is good, it is usually in the range of 1.0 to 4.0, preferably in the range of 1.0 to 3.0, more preferably in the range of 2.0 to 3.0. is there. It is important to adjust the pH within this range in order to obtain an antifouling-treated wood having excellent antifouling properties. In particular, when a commercially available product is used as the cationic resin (A), the acid catalyst (C) is gradually added. It is preferable to adjust the pH while dropping the solution.

[Water-based paint composition for wood]
As a method for preparing the aqueous coating composition for wood according to the present invention, an aqueous dispersion of a cationic resin (A) and an acid catalyst (C) are mixed and homogenized, and then a metal alkoxide or a condensate thereof (B). Is most preferably mixed. In addition, the alcohol produced by hydrolysis of the metal alkoxide or its condensate (B) may be left as the water-based coating composition for wood of the present invention, and may be allowed to stand or warm under various methods such as reduced pressure. By doing this, after removing the alcohol, a water-based paint composition for wood may be used.

  Various additives such as thickeners, wetting agents, thixotropic agents, fillers, and the like may be added to the water-based paint composition for wood of the present invention as long as the effects of the present invention are not hindered. Further, a crosslinking agent that reacts with the functional group in the cationic resin (A), for example, a crosslinking agent such as a polyepoxy compound, a dialdehyde compound, or a dicarboxylic acid compound may be used in combination.

  In addition, the water-based paint composition for wood of the present invention can be suitably used as a clear paint composition. It can be applied from the viewpoint of excellent wear resistance and stain resistance.

  The non-volatile content of the wood-based water-based paint composition of the present invention is not particularly limited, and may be any non-volatile content taking into consideration the viscosity suitable for the coating method, but is usually 10% by mass or more and 50% by mass. The following is preferable from the viewpoint of good storage stability.

  The method for coating the wood-based water-based paint composition of the present invention on wood is not particularly limited. For example, brush coating method, brush coating wiping method, roll coater method, flow coater method, spray method / dipping It can be applied by various coating methods such as an (immersion) method. Among these, the roll coater method and the flow coater method are particularly preferable because the coating amount can be easily controlled.

  The coating object of the wood-based water-based coating composition of the present invention is not particularly limited as long as it is wood. For example, domestic hardwoods such as paulownia, oak, beech, maple, etc., domestic conifers such as pine, oak, cedar, etc., Southwestern wood such as ebony, teak, rubber, etc., North American wood such as walnut, oak, cherry, macore, bubinga, kaya, etc. It can be used for African materials.

  Furthermore, for the purpose of improving adhesion to the base material, coloring the base material, protecting the base material, and the like, after applying sunscreen agents, colored stains, wood sealers, etc. to the above-mentioned various woods, the aqueous water for wood of the present invention The coating composition can also be applied.

  Moreover, it is although it does not specifically limit as drying conditions after coating, It is made to dry for 10 second-24 hours between 20 degreeC-120 degreeC from the point from which a coating film is obtained without causing deformation | transformation of wood itself. It is preferable that the drying be performed between 60 ° C. and 100 ° C. for 10 seconds to 30 minutes.

  On the surface of the treated wood obtained in the present invention, particles of the cationic resin (A) are dispersed in a matrix made of a metal oxide (B ′).

  The metal oxide (B ′) is obtained by hydrolysis / condensation reaction of the metal alkoxide or the condensate (B) described above, and forms a matrix in the coating film. This is because the metal gel is concentrated so as to surround the surface of the fine particles formed by the cationic resin (A) in the aqueous dispersion as described above. It is formed by cross-linking the surface metal gel. Therefore, the fine particles of the cationic resin (A) are not condensed and are dispersed in the coating film. With such a structure, even with a thin film, antifouling treated wood with high stain resistance, abrasion resistance and water resistance, high design quality without damaging the texture and grain peculiar to wood can be obtained. .

  The antifouling treated wood of the present invention is an aqueous coating composition for wood obtained by adding an acid catalyst (C) to an aqueous dispersion of a cationic resin (A) and then adding a metal alkoxide or a condensate (B) thereof. By applying a coating on a substrate and drying, a composite coating film in which particles made of a cationic resin (A) are dispersed in a matrix made of a metal oxide (B ′) is produced on the wood surface. It is characterized by being obtained. The manufacturing method is industrially simple and useful because it does not require any special equipment and does not use moisture in the air, so it has no environmental dependency and is therefore not limited to the application range. It is a thing.

The coating amount of the waterborne paint composition for wood (after drying) is not particularly limited, but has a sufficient balance of performance and does not impair the texture of the wood surface, such as unevenness and grain, preferably it is applied in a range of ^{1g / m 2 ~50g / m 2} , more preferably from ^{1g / m 2 ~20g / m 2} .

  The use of the antifouling treated wood obtained in the present invention is not particularly limited. For example, flooring materials, construction materials such as baseboards, stairs and handrails, doors and members thereof, columns, wall materials, tables It can be suitably used for furniture such as chairs and organizers. Wood treated in this way requires little post-installation maintenance, and kitchens and washrooms are likely to be exposed to pollutants such as seasonings, cosmetics, detergents, and bleaching agents where solid wood could not be used. It can also be used for water-related members such as places, so that maintenance can be reduced and durability can be improved.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the examples. Unless otherwise specified, “parts” and “%” represent “parts by mass” and “mass%”.

(Synthesis example 1) Preparation of aqueous dispersion of cationic urethane resin (A-1-1) Polypropylene glycol-diglycidyl ether (into a four-necked flask equipped with a thermometer, a stirring device, a reflux condenser, and a dropping device) After 590 parts of epoxy equivalent 201 g / equivalent), the inside of the flask was purged with nitrogen. Subsequently, after heating using the oil bath until the temperature in the said flask becomes 70 degreeC, 378 parts of di-n-butylamine is dripped in 30 minutes using a dripping apparatus, and 10 degreeC is 90 degreeC after completion | finish of dripping. Reacted for hours. After completion of the reaction, using an infrared spectrophotometer (FT / IR-460Plus, manufactured by JASCO Corporation), it is confirmed that the absorption peak near 842 cm ⁻¹ due to the epoxy group of the reaction product has disappeared. A tertiary amino group-containing polyol (amine equivalent 339 g / equivalent, hydroxyl equivalent 339 g / equivalent) was obtained.

  In a four-necked flask equipped with a thermometer, a stirrer, a reflux condenser, and a dropping device, 500 parts of Nipponran 980R [Nippon Polyurethane Industry Co., Ltd., Polycarbonate polyol, molecular weight 2000], neopentyl glycol / 1,4-butane 500 parts of a polyester polyol (molecular weight 2000) composed of diol / terephthalic acid / adipic acid was dissolved in 558 parts of ethyl acetate. Next, after adding 236 parts of 4,4′-dicyclohexylmethane diisocyanate and 0.2 part of stannous octylate and reacting at 75 ° C. for 2 hours, 66.2 parts of the tertiary amino group-containing polyol was added, By making it react for 4 hours, the urethane prepolymer which has an isocyanate group at the terminal was obtained. Next, 478 parts of ethyl acetate and 918 parts of isopropyl alcohol were added to the urethane prepolymer solution and mixed uniformly, and then 17 parts of 80% hydrated hydrazine was added to carry out a chain extension reaction for 1 hour. Next, 11.7 parts of glacial acetic acid was added for neutralization, and 3610 parts of ion-exchanged water was added dropwise to carry out water dispersion, followed by desolvation under reduced pressure to obtain a non-volatile content of 35% and a pH of 4 2. An aqueous dispersion of a cationic polyurethane resin (A-1-1) having a particle size of 0.2 μm (measured by a particle size analyzer FPAR-1000 manufactured by Otsuka Electronics Co., Ltd.) and a cation equivalent of 0.15 equivalent / kg. Obtained.

(Synthesis Example 2) Preparation of aqueous dispersion of cationic polyurethane resin (A-1-2) In a four-necked flask equipped with a thermometer, a stirrer, a reflux condenser, and a dropping device, 1000 parts of NIPPOLAN 980R were Dissolved in 600 parts of ethyl acetate. Next, 262 parts of 4,4′-dicyclohexylmethane diisocyanate and 0.2 part of stannous octylate were added and reacted at 75 ° C. for 2 hours, and then 95 parts of the tertiary amino group-containing polyol was added and reacted for 4 hours. After cooling to 60 ° C., 44 parts of Z-6011 [γ-aminopropyltriethoxysilane manufactured by Toray Dow Corning Co., Ltd.] was added, and the mixture was further reacted for 1 hour to make a urethane prepolymer having an isocyanate group at the terminal. A polymer was obtained. Next, 515 parts of ethyl acetate and 986 parts of isopropyl alcohol were added to the urethane prepolymer solution and mixed uniformly, and then 15 parts of 80% hydrated hydrazine was added to carry out a chain extension reaction for 1 hour. Next, after 16.8 parts of glacial acetic acid was added for neutralization, 3800 parts of ion-exchanged water was added dropwise to carry out water dispersion, followed by desolvation under reduced pressure to obtain a non-volatile content of 35% and a pH of 4 An aqueous dispersion of a cationic urethane resin (A-1-2) having a particle diameter of 0.15 μm and a cation equivalent of 0.2 equivalent / kg was obtained.

(Synthesis example 3) Preparation of aqueous dispersion of cationic polyurethane resin (A-1-3) In a four-necked flask equipped with a thermometer, a stirring device, a reflux condenser, and a dropping device, 640 parts of Nipponran 980R Dissolved in 390 parts of methyl ethyl ketone. Next, 133 parts of isophorone diisocyanate and 0.2 part of stannous octylate were added and reacted at 75 ° C. for 2 hours, and then 122 parts of the tertiary amino group-containing polyol was added and reacted for 4 hours. After cooling to ° C., 22 parts of Z-6011 were added and reacted for 1 hour to obtain a urethane prepolymer having an isocyanate group at the terminal. Next, 45 parts of dimethylsulfuric acid was added to the urethane prepolymer solution, and the mixture was further reacted at 60 ° C. for 2 hours for quaternization. Then, 2080 parts of ion-exchanged water was added dropwise to carry out water dispersion, followed by reduced pressure. By removing the solvent below, an aqueous dispersion of cationic polyurethane resin particles (A-1-3) having a nonvolatile content of 35%, a pH of 6.5, a particle diameter of 0.05 μm, and a cation equivalent of 0.39 equivalent / kg is obtained. It was.

( Reference synthesis example 1 ) Preparation of aqueous dispersion (A-2-1) of cationic acrylic resin Reaction equipped with stirrer, thermometer, dropping funnel, reflux condenser, inert gas inlet and outlet While introducing nitrogen into the container, 12 parts of methacryloxyethyltrimethylammonium chloride, 0.4 part of n-dodecyl mercaptan, 1 part of 2,2′-azobis (2-methylpropionamidine) dihydrochloride, ion-exchanged water 540 A reaction product was obtained by adding a portion, raising the internal temperature to 80 ° C. while stirring, and maintaining the same temperature for 1 hour for reaction. Next, a monomer mixture (220 parts of butyl acrylate and 180 parts of methyl methacrylate) preliminarily mixed in another container and a polymerization initiator aqueous solution (2,2′-azobis) in a reaction container in which the reaction product is present. 40 parts of (2-methylpropionamidine) dihydrochloride 5% aqueous solution) were dropped from another dropping funnel over 3 hours and polymerized. During the dropping, the temperature inside the reaction vessel was maintained at 80 ° C. After completion of the dropwise addition, the liquid temperature was further stirred at 80 ° C. for 1 hour, then cooled to 25 ° C., adjusted with ion-exchanged water so that the non-volatile content was 35%, PH 3.5, particle size 0.3 μm, An aqueous dispersion of a cationic acrylic resin (A-2-1) having a cation equivalent of 0.14 equivalent / kg was obtained.

( Reference synthesis example 2 ) Preparation of aqueous dispersion (A-2-2) of cationic acrylic resin Reaction equipped with stirrer, thermometer, dropping funnel, reflux condenser, inert gas inlet and outlet 425 parts of propylene glycol-n-propyl ether is charged in a container and kept at 100 ° C. with stirring in a nitrogen atmosphere, and about 500 parts of a mixture consisting of 35 parts of dimethylaminoethyl methacrylate, 300 parts of methyl methacrylate and 165 parts of butyl acrylate is added. Drip slowly over time. In parallel, a solution consisting of 10 parts of t-butyl peroxy-2-ethylhexanoate (trade name Perbutyl O, manufactured by NOF Corporation) and 65 parts of propylene glycol-n-propyl ether is slowly added over about 3 hours. And dripped. One hour after the completion of dropping, a solution consisting of 2.5 parts of perbutyl O and 10 parts of propylene glycol-n-propyl ether was added, and the liquid temperature was kept at 100 ° C. for 3 hours to complete the polymerization reaction. Next, after adding 13.5 parts of glacial acetic acid and neutralizing by thorough stirring and mixing, 980 parts of ion-exchanged water is added dropwise to carry out water dispersion, followed by further desolvation under reduced pressure. Thus, an aqueous dispersion of a cationic acrylic resin (A-2-2) having a nonvolatile content of 35%, a pH of 5.8, a particle diameter of 0.1 μm, and a cation equivalent of 0.44 equivalent / kg was obtained.

(Comparative Synthesis Example 1)
A reaction vessel equipped with a stirrer, thermometer, reflux condenser and inert gas inlet and outlet was charged with 116 parts of hexamethylenediamine and maintained at 50 ° C. with stirring under a nitrogen atmosphere. Propylene carbonate was slowly added dropwise over about 1 hour. When the reaction vessel was kept at 90 to 100 ° C. for 20 hours, hexamethylenediamine bishydroxycarbamate (hereinafter referred to as A′-1), which was a white waxy soft solid, was obtained. As a result of acid titration, the amine content was 0.1% or less.

(Comparative Synthesis Example 2)
A reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, a reflux condenser, and an inert gas inlet and outlet tube was charged with 425 parts of propylene glycol-n-propyl ether and stirred at 100 ° C. in a nitrogen atmosphere. Then, 500 parts of a mixture consisting of 100 parts of dimethylaminoethyl methacrylate, 260 parts of methyl methacrylate and 140 parts of butyl acrylate was slowly added dropwise over about 3 hours. In parallel, a solution consisting of 10 parts perbutyl O and 65 parts propylene glycol-n-propyl ether was slowly added dropwise over about 3 hours. One hour after the completion of the dropping, a solution comprising 2.5 parts of perbutyl O and 10 parts of propylene glycol-n-propyl ether was added, and the polymerization temperature was further maintained at 100 ° C. for 3 hours to complete the polymerization reaction. Next, after 38.2 parts of glacial acetic acid was added and well mixed by stirring and neutralized, 980 parts of ion-exchanged water was added dropwise and stirred, followed by desolvation under reduced pressure to obtain a non-volatile content of 35%. A transparent aqueous solution of a cationic acrylic resin (A′-2) having a pH of 6.0 and a cation equivalent of 1.27 equivalents / kg was obtained.

[Coating composition]
Example 1
After stirring and mixing 20 parts of an aqueous dispersion of the cationic urethane resin (A-1-1) obtained in Synthesis Example 1, 5 parts of ion-exchanged water, and 8 parts of 2-propanol (hereinafter referred to as IPA), 10 7 parts of a% maleic acid aqueous solution was gradually added dropwise. The pH of the mixed solution at this time was 1.6. Subsequently, 14.4 parts of tetramethoxysilane condensate (methyl silicate 51: product of Tama Chemical Industry Co., Ltd., hereinafter referred to as MS-51) and 3-glycidoxypropyltrimethoxysilane (hereinafter referred to as GPTMS) are stirred. The mixed liquid consisting of 4.3 parts was gradually added and stirred for 1 hour to obtain an aqueous wood coating composition (1) for wood.

(Examples 2 to 16 and Reference Examples 1 to 7 )
In the same manner as in Example 1, the wood-based water-based coating composition was prepared with the formulations shown in Tables 1 to 3 to obtain wood-based water-based coating compositions (2) to (23).

(Comparative Example 1)
20 parts of tetraethoxysilane (hereinafter referred to as TEOS) and curing were added to a solution obtained by mixing 15 parts of the hydroxyl group-containing polymer A′-1 synthesized in Comparative Synthesis Example 1, 15 parts of ion-exchanged water, and 5 parts of methanol. As an agent, 0.5 part of melamine resin Cymel 303 (manufactured by Cytec Corporation) was added to prepare a uniform solution. To this solution, 0.3 part of concentrated hydrochloric acid as a catalyst was added and heated at about 30 ° C. for 1 hour to obtain a comparative aqueous coating composition (1 ′).

(Comparative Example 2)
After stirring and mixing 20 parts of the aqueous solution of the cationic acrylic resin (A-2 ′) obtained in Comparative Synthesis Example 2, 8.5 parts of ion-exchanged water, and 8 parts of 2-propanol (hereinafter referred to as IPA), 10 parts 3.9 parts of a% maleic acid aqueous solution was gradually added dropwise. The pH of the mixed solution at this time was 2.3. Subsequently, a mixed liquid consisting of 14.4 parts of MS-51 and 4.3 parts of GPTMS was gradually added with stirring, followed by stirring for 1 hour to obtain a comparative aqueous coating composition (2 ′).

(Stability evaluation method of water-based paint composition for wood)
The number of days until gelation occurs by visually observing the coating liquid state when the aqueous coating compositions obtained in Examples 1 to 16, Reference Examples 1 to 7 , and Comparative Examples 1 to 2 are stored at 23 ° C. Was described.

Footnotes in Tables 1 to 4 (A) / (B1): ratio of the mass of the cationic resin (A) to the mass (B1) after hydrolytic condensation of the metal alkoxide or its condensate (B) SF650: Superflex 650 Manufactured by Daiichi Kogyo Seiyaku Co., Ltd. Cationic urethane resin aqueous dispersion, 25% non-volatile content, average particle size 0.01 μm
UW550CS: Acryt UW550-CS, manufactured by Taisei Fine Chemical Co., Ltd. Cationic acrylic resin aqueous dispersion, non-volatile content 34%, average particle size 0.04 μm
MTMS: Methyltrimethoxysilane

[Coating]
(Examples 17 to 32, and Reference Examples 8 to 14)
Natural coater (see FIG. 1) in which the aqueous coating compositions for wood (1) to (23) obtained in Examples 1 to 16 and Reference Examples 1 to 7 are provided with a sponge rubber roll on a beech material (12 mm thick). Was applied so that the coating amount after drying was about 5 g / m 2, and then dried for 90 seconds with a warm air dryer set at 90 ° C. to obtain antifouling treated wood.
Painting process:
(I) Applying and impregnating with a sponge natural (sponge-like rubber roll) coater (ii) Using a reverse (scraping) coater, scrape excess paint on the surface while pushing the paint into the substrate.
(Iii) Apply thinly with a natural (rubber) coater.

(Comparative Examples 3-4)
The aqueous paint compositions (1 ′) to (2 ′) obtained in Comparative Examples 1 and 2 were applied onto beech materials in the same manner as in Examples to obtain comparative test wood. At this time, in Comparative Example 3 using the water-based coating composition obtained in Comparative Example 1, some tack remained on the wood surface even after drying. The contamination resistance test and the chemical resistance test were performed on the surface as they were.

(Comparative Example 5)
A beech material (uncoated product) used as a base material was used as a comparative test wood.

(Evaluation)
The following tests were performed on the obtained antifouling treated wood and comparative test wood.
Contamination resistance test: “Contamination resistance” and “Chemical resistance” in “Standards of surface performance” in Article 8 “Standards for Specially Treated Decorative Plates” in “Japanese Agricultural Standards for Plywood” by Ministry of Agriculture, Forestry and Fisheries Notification No. 233 The test was conducted by a test method according to the test items defined in “1.

  A black magic, red magic, blue magic (as defined in JIS S6307 marking pen), black ink, blue ink, and red crayon were used as contaminants in the stain resistance test, and the test was conducted for 24 hours. The test was conducted for 24 hours using 5% acetic acid aqueous solution, 1% sodium carbonate, 60% ethanol aqueous solution, JAS lacquer thinner (JIS K5538 lacquer thinner) as chemicals for chemical resistance test. The results are summarized in Tables 5-8.

Judgment criteria (visual)
Contamination resistance test ◎: No dirt residue ○: There is a little dirt residue, but there is no practical problem. △: There is a little dirt residue, but it does not penetrate inside.
X: Dirt remains.
XX: Dirt is diffused and penetrates into the interior and cannot be removed.
Chemical resistance test ◎: No discoloration ○: There is a slight discoloration, but there is no practical problem.
Δ: There is a slight discoloration, but it does not penetrate inside.
×: Discoloration

  The antifouling-treated wood surface obtained in the examples had a grain that was indistinguishable from an unpainted product (Comparative Example 5) by visual observation, and there was no shine when applying wax or the like. Furthermore, the unevenness of the beech material used as a base material is not damaged (see the drawing. Note that the equipment used for SEM photo measurement is a real surface view microscope VE-7800 manufactured by Keyence Corporation).

It is the coating machine used in the Example. 2 is a photograph of the antifouling treated wood obtained in Example 24 after a test. It is a photograph after the test of the antifouling treated wood obtained in Reference Example 8 . It is the photograph after the test of the comparative example 5 (unpainted goods). 2 is a SEM photograph of the surface of an antifouling treated wood obtained in Example 24. 10 is a SEM photograph of the surface of an antifouling treated wood obtained in Reference Example 8 . It is a SEM photograph of the surface of comparative example 5 (unpainted article).

Claims (5)

It contains an aqueous dispersion of a cationic resin (A) having a structural unit represented by the following general formula (I), a metal alkoxide or a condensate thereof (B), and an acid catalyst (C). Water-based paint composition for wood.

(In the formula (I), R ₁ is an alkylene chain that may contain an aliphatic cyclic structure, a residue of a dihydric phenol, or a polyoxyalkylene chain, and R ₂ and R ₃ are independent of each other. R ₄ is a hydrogen atom or a residue of a quaternizing agent introduced by a quaternization reaction, and X − is an anionic counter ion. is there.) The metal alkoxide or its condensation product (B) is a silicon alkoxide or its condensate in a claim 1 Symbol placement wood aqueous coating composition. The aqueous coating composition for wood according to claim 1 or 2, wherein the metal alkoxide or the condensate thereof is a combination of tetraalkoxysilane or the condensate thereof and 3-glycidoxypropyltrimethoxysilane. The ratio of the mass of the cationic resin (A) to the mass (B1) after hydrolytic condensation of the metal alkoxide or its condensate (B) is 10 / in the mass ratio represented by (A) / (B1). It is the range of 90-70 / 30, The water-based coating composition in any one of Claims 1-3 . An antifouling-treated wood obtained by applying the aqueous coating composition for wood according to any one of claims 1 to 4 onto wood and drying it.

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