Wood protection paints and building exterior materials

Abstract

To provide a wood protective coating that forms a coating layer having high light transmittance and can improve the weather resistance of wood and a member for external facing.SOLUTION: A wood protective coating contains A agent and B agent. The A agent contains (a1) polycarbonate diol, (a2) ultraviolet absorber, and (a3) light stabilizer. The B agent contains hexamethylene diisocyanate, or a hexamethylene diisocyanate derivative. A coating layer with a thickness of 0.15 mm formed from the wood protective coating has a light transmittance of 19% or more at a wavelength of 650-750 nm, and has a light transmittance of 80% or less at a wavelength of 400 nm.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to wood protection coatings and exterior building components. [Background technology]

[0002] Patent Documents 1 and 2 disclose wood protective coatings. The wood protective coatings are applied to wood. The purpose of the wood protective coatings is to improve the weather resistance of wood. Weather resistance is, for example, the property of preventing color changes in wood even when exposed to light for a long period of time. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-108461 [Patent Document 2] Japanese Patent Application Publication No. 2019-069538 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional wood protective coatings, if the light transmittance of the coating film is increased to the point where the wood grain is visible through the coating film, the weather resistance of the wood will decrease. In one aspect of the present disclosure, it is preferable to provide a wood protective coating and a building exterior component that have high light transmittance and can improve the weather resistance of wood. [Means for solving the problem]

[0005] One aspect of the present disclosure is a wood protective coating. The wood protective coating comprises component A and component B. Component A comprises (a1) polycarbonate diol, (a2) an ultraviolet absorber, and (a3) ​​a light stabilizer. Component B comprises hexamethylene diisocyanate or a hexamethylene diisocyanate derivative. A coating film having a thickness of 0.15 mm formed by the wood protective coating has a light transmittance of 19% or more at a wavelength of 650 to 750 nm and a light transmittance of 80% or less at a wavelength of 400 nm.

[0006] The wood protection coating according to one aspect of the present disclosure can be applied to wood to form a coating film. The coating film has high light transmittance, making it easy to see the grain of the wood through the coating film. Furthermore, changes in the color tone of the wood can be suppressed.

[0007] Another aspect of the present disclosure is a building exterior member comprising wood and a coating film formed on the wood. The coating film contains (c1) a reaction product of polycarbonate diol with hexamethylene diisocyanate or a hexamethylene diisocyanate derivative, (c2) an ultraviolet absorber, and (c3) a light stabilizer. The coating film has a thickness of 0.15 mm and has a light transmittance of 19% or more at wavelengths of 650 to 750 nm and 80% or less at a wavelength of 400 nm.

[0008] The coating film provided on the building exterior component according to another aspect of the present disclosure has high light transmittance, making it easy to see the grain of the wood through the coating film, and also suppressing changes in the color tone of the wood. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1A is an explanatory diagram showing the chemical formula of a biuret-type hexamethylene diisocyanate derivative, FIG. 1B is an explanatory diagram showing the chemical formula of an isocyanurate-type hexamethylene diisocyanate derivative, FIG. 1C is an explanatory diagram showing the chemical formula of an adduct-type hexamethylene diisocyanate derivative, and FIG. 1D is an explanatory diagram showing the chemical formula of a bifunctional hexamethylene diisocyanate derivative. DETAILED DESCRIPTION OF THE INVENTION

[0010] Exemplary embodiments of the present disclosure will now be described with reference to the drawings. 1.Wood protection paint (1-1) Uses of wood protection paint Wood protective paints are used, for example, to protect wood. Wood protective paints are applied, for example, to the surface of wood. Wood protective paints may be primer paints or topcoats.

[0011] A primer is a paint that is applied directly to the surface of wood. A topcoat is a paint that is applied over a coating that has already formed on the surface of wood. The coating that has already formed on the surface of wood is, for example, a coating that has been formed by applying a primer.

[0012] The primer paint has the effect of improving adhesion between the wood and the coating film and preventing discoloration of the wood. The top coat paint has the effect of improving the aesthetic appearance and preventing discoloration of the wood. The primer paint and the top coat paint may be the same paint or different paints.

[0013] When the wood protective coating is a primer coating, the thickness of the coating film of the wood protective coating is preferably 10 μm or more and 200 μm or less, and more preferably 30 μm or more and 100 μm or less. When the wood protective coating is a top coat coating, the thickness of the coating film of the wood protective coating is preferably 5 μm or more and 100 μm or less, and more preferably 10 μm or more and 50 μm or less. The coating thickness is measured using a micrometer. When the topcoat paint and the primer paint are each the wood protection paint of the present disclosure, it is preferable that the hexamethylene diisocyanate or hexamethylene diisocyanate derivative in agent B of the primer paint is a biuret type, and the hexamethylene diisocyanate or hexamethylene diisocyanate derivative in agent B of the topcoat paint is an isocyanurate type. When hexamethylene diisocyanate or a hexamethylene diisocyanate derivative is selected as described above, the adhesion of the primer paint film to wood is further improved, and the weather resistance of the top coat paint film is further improved, which results in the primer paint film and the top coat paint film being more unlikely to peel off from the wood surface, further improving the weather resistance of the wood.

[0014] (1-2) Agent A and Agent B Wood protection paints contain components A and B. Component B is, for example, a hardener. Components A and B are kept separate when not in use. When in use, components A and B are mixed. The liquid obtained by mixing components A and B is hereinafter referred to as a mixed liquid. The mixed liquid, or a diluted version of the mixed liquid, can be applied to wood.

[0015] The wood protective coating may contain other agents in addition to Agent A and Agent B. Examples of other agents include thinners. The thinners can dilute the mixed liquid. The thinners are, for example, the same solvents as those contained in Agent A or Agent B.

[0016] (1-3) Agent A The component A contains (a1) a polycarbonate diol, (a2) an ultraviolet absorber, and (a3) ​​a light stabilizer. The polycarbonate diol is obtained by reacting a diol with a carbonating agent. Examples of the diol include linear diols, branched diols, and cyclic diols. The linear diols and branched diols are aliphatic diols.

[0017] Examples of linear diols include 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-dodecanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, and 1,15-pentadecanediol.

[0018] Examples of branched diols include 2-methyl-1,8-octanediol, 2-ethyl-1,6-hexanediol, 2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,4-dimethyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, and 2,2-dimethyl-1,3-propanediol.

[0019] Examples of cyclic diols include 1,4-cyclohexanedimethanol, 2-bis(4-hydroxycyclohexyl)-propane, 1,4-cyclohexanediol, etc. The diol that is the raw material for the polycarbonate diol may be one of the above-mentioned diols or a combination of two or more of them.

[0020] The diol that is the raw material of the polycarbonate diol is preferably at least one selected from the group consisting of 1,4-butanediol, 1,3-propanediol, 1,5-pentanediol, 1,6-hexanediol, 2-methyl-1,3-propanediol, and 3-methyl-1,5-pentanediol among the above-mentioned diols.

[0021] The diol that is the raw material for the polycarbonate diol is preferably a combination of 1,4-butanediol and one or more selected from the group consisting of 1,3-propanediol, 1,5-pentanediol, and 1,6-hexanediol, and more preferably 1,5-pentanediol and 1,6-hexanediol are copolymerized.

[0022] Examples of the carbonating agent include dialkyl carbonate, diaryl carbonate, alkylene carbonate, etc. Examples of the dialkyl carbonate include dimethyl carbonate, diethyl carbonate, dipropyl carbonate, dibutyl carbonate, etc. Examples of the diaryl carbonate include diphenyl carbonate, etc.

[0023] Examples of alkylene carbonates include ethylene carbonate, trimethylene carbonate, 1,2-propylene carbonate, 1,2-butylene carbonate, 1,3-butylene carbonate, 1,2-pentylene carbonate, etc. The carbonating agent may be one of the above-mentioned carbonating agents, or a combination of two or more of them.

[0024] The polycarbonate diol is preferably an aliphatic polycarbonate diol, and more preferably an amorphous aliphatic polycarbonate diol. Commercially available polycarbonate diols include Burnock (manufactured by DIC), Duranol (manufactured by Asahi Kasei), and Nipporan (manufactured by Tosoh).

[0025] Examples of the ultraviolet absorber include benzotriazole-based ultraviolet absorbers, triazine-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, benzoate-based ultraviolet absorbers, iron oxide, and titanium oxide.

[0026] Examples of benzotriazole-based ultraviolet absorbers include 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-di-tert-amylphenyl)benzotriazole, 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole, 2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-tert-octylphenol], 6-(2-benzotriazolyl)-4-tert-octyl-6'-tert-butyl- Examples of such phenols include 4'-methyl-2,2'-methylenebisphenol, 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol, 2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol], 2-methylenebis[6-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol], 2-(2H-benzotriazol-2-yl)-p-cresol, and 2-(5-chloro-2H-benzotriazol-2-yl)-6-tert-butyl-4-methylphenol.

[0027] Examples of triazine-based ultraviolet absorbers include 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[2-(2-ethylhexanoyloxy)ethoxy]phenol and 2,4,6-tris(2-hydroxy-4-hexyloxy-3-methylphenyl)-1,3,5-triazine.

[0028] Examples of benzophenone-based ultraviolet absorbers include [2-hydroxy-4-(octyloxy)phenyl](phenyl)methanone. The ultraviolet absorber is preferably a triazine-based ultraviolet absorber, particularly 2-(4,6-bis(2,4dimethylphenyl)-1,3,5-triazin-2-yl)-5-hydroxyphenyl, benzenepropanoic acid 3-(2H-benzotriazol-2-yl)-5-(1,1-dimethylethyl)-4-hydroxy C7-9 side chain and linear alkyl ester, or 2,4,6-tris(2-hydroxy-4-hexyloxy-3-methylphenyl)-1,3,5-triazine.

[0029] 2-(4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl)-5-hydroxyphenyl and benzenepropanoic acid 3-(2H-benzotriazol-2-yl)-5-(1,1-dimethylethyl)-4-hydroxy C7-9 side chain and straight chain alkyl ester are colorless and transparent. Therefore, when component A contains these compounds, changes in appearance can be suppressed when the wood protection coating is applied to wood.

[0030] Examples of the light stabilizer include hindered amine light stabilizers. Examples of the hindered amine light stabilizer include bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, tetrakis(1,2,2,6,6-pentamethyl-4-piperidyl)butane-1,2,3,4-tetracarboxylate, tetrakis(2,2,6,6-tetramethyl-4-piperidyl)butane-1,2,3,4-tetracarboxylate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, and bis(2,2,6,6-tetramethyl-4-piperidyl). sebacate, bis(1-undecanoxy-2,2,6,6-tetramethylpiperidin-4-yl)carbonate, 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate, 2,2,6,6-tetramethyl-4-piperidyl methacrylate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butylmalonate, and the like.

[0031] Among the hindered amine light stabilizers, sebacate hindered amine light stabilizers are preferred. Examples of the sebacate hindered amine light stabilizer include bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate and methyl 1,2,2,6,6-pentamethyl-4-piperidylsebacate.

[0032] Agent A contains an ultraviolet absorber and a light stabilizer. By including an ultraviolet absorber and a light stabilizer in Agent A, changes in the appearance of the wood material can be suppressed when the wood protective coating is applied to the wood material. Elements of appearance include, for example, wood grain and color tone.

[0033] The total mass of the polycarbonate diol and hexamethylene diisocyanate or hexamethylene diisocyanate derivative contained in the mixed solution is assumed to be 100 parts by mass. The total mass of the ultraviolet absorber and light stabilizer contained in the mixed solution is assumed to be X parts by mass. The value of X is preferably larger when the wood protective coating is a topcoat coating than when the wood protective coating is a primer coating.

[0034] When the wood protective coating is a primer coating, the value of X is preferably 1 or more and 10 or less, and more preferably 2 or more and 8 or less. When the wood protective coating is a topcoat coating, the value of X is preferably 3 or more and 20 or less, and more preferably 5 or more and 10 or less.

[0035] When the wood protective coating is a topcoat, component A may contain a matting agent. Examples of matting agents include silica-based matting agents and synthetic resin-based matting agents. Examples of silica-based matting agents include finely powdered silica and colloidal silica. Examples of synthetic resin-based matting agents include urethane beads and acrylic beads. The optical refractive index of the matting agent is, for example, less than 3.

[0036] The average particle size of the matting agent is preferably 0.1 μm or more and 10 μm or less. When the average particle size is 0.1 μm or more and 10 μm or less, the effect of suppressing the gloss of the coating film is even greater. The amount of silica-based matting agent added is preferably 10% by mass or more and 30% by mass or less based on the polycarbonate diol. When the content of silica-based matting agent is 30% by mass or less, the light transmittance of the coating film is less likely to decrease.

[0037] (1-4) Agent B The agent B contains hexamethylene diisocyanate or a hexamethylene diisocyanate derivative. Examples of hexamethylene diisocyanate include adduct type, isocyanurate type, biuret type, and bifunctional type. As hexamethylene diisocyanate, isocyanurate type and biuret type are preferred, and isocyanurate type is more preferred.

[0038] Hexamethylene diisocyanate derivatives are compounds in which multiple hexamethylene diisocyanates are chemically bonded. Examples of hexamethylene diisocyanate derivatives include adduct types, isocyanurate types, biuret types, and bifunctional types. As the hexamethylene diisocyanate derivative, isocyanurate types and biuret types are preferred, and isocyanurate types are more preferred.

[0039] 1A to 1D show an adduct-type hexamethylene diisocyanate derivative, an isocyanurate-type hexamethylene diisocyanate derivative, a biuret-type hexamethylene diisocyanate derivative, and a bifunctional hexamethylene diisocyanate derivative. R in Fig. 1A to 1D is a hexamethylene group.

[0040] Commercially available hexamethylene diisocyanate derivatives include, for example, Coronate (manufactured by Tosoh), Sumidur, Dismodur (manufactured by Sumika Bayer Urethane), and Duranate (manufactured by Asahi Kasei).

[0041] The number of moles of NCO of hexamethylene diisocyanate or hexamethylene diisocyanate derivatives contained in the mixture is M NCO In addition, the number of moles of OH groups in the polycarbonate diol contained in the mixed solution is M OHLet's say. M NCO / M OH The value of is preferably 0.5 or more and 1.5 or less, and more preferably 0.8 or more and 1.2 or less.

[0042] It is preferable that component A contains a polycarbonate diol copolymerized with 1,5-pentanediol and 1,6-hexanediol, and component B contains an isocyanurate-type hexamethylene diisocyanate derivative. In this case, the coating film formed by applying the wood protective coating to the wood surface has a good balance between flexibility and hardness. As a result, the coating film has excellent durability.

[0043] The component B may contain, for example, a curing accelerator. A commonly used curing accelerator can be used. Examples of the curing accelerator include amines and metal catalysts. Examples of the amines include triethylamine, N,N-dimethylcyclohexylamine, tetramethylethylenediamine, other triamines, cyclic amines, dimethylethanolamine, and ether amines.

[0044] Examples of metal catalysts include potassium acetate, potassium 2-ethylhexanoate, calcium acetate, lead octoate, dibutyltin dilaurate, tin octoate, bismuth neodecanoate, bismuth oxycarbonate, bismuth 2-ethylhexanoate, zinc octoate, zinc neodecanoate, phosphine, and phospholine.

[0045] (1-5) Light transmittance of coating film The 0.15 mm thick coating film formed by applying the wood protective coating has a light transmittance of 19% or more at wavelengths of 650 to 750 nm. The light transmittance at wavelengths of 650 to 750 nm is preferably 40% or more. A light transmittance of 19% or more at wavelengths of 650 to 750 nm makes it easy to see the wood grain through the coating film. Furthermore, the 0.15 mm thick coating formed by applying the wood protective coating has a light transmittance of 80% or less at a wavelength of 400 nm. By having a light transmittance of 80% or less at a wavelength of 400 nm, changes in appearance when the wood protective coating is applied to wood can be suppressed.

[0046] The method for measuring light transmittance is as follows. The mixed liquid is applied to the substrate using a bar coater to form a coating film 0.15 mm thick. The substrate is a PP board. The area where the coating film is formed is 20 mm wide and 40 mm long. The measurement sample is placed in front of the integrating sphere of an ultraviolet-visible spectrophotometer (Shimadzu Corporation, model UV-2100) and the light transmittance is measured. The measurement resolution is in 5 nm increments.

[0047] The thinner the coating film, the higher the light transmittance of the coating film. The lower the concentration of the high refractive index pigment in the mixed solution, the higher the light transmittance of the coating film. When the wood protective coating is a primer coating, the concentration of the high refractive index pigment in the mixed solution is preferably 10% by mass or less, and more preferably 2% by mass or less.

[0048] When the wood protective coating is a topcoat, the concentration of the high refractive index pigment in the mixed solution is preferably 15% by mass or less, and more preferably 10% by mass or less. The refractive index of a compound obtained by reacting and curing polycarbonate diol with hexamethylene diisocyanate or a hexamethylene diisocyanate derivative is around 1. A high refractive index pigment is a pigment with a refractive index of 3 or more.

[0049] (1-6) Other ingredients When the wood protective coating is a topcoat or primer, one or both of component A and component B may contain an organic solvent as needed. The content of the organic material is, for example, 0% by mass or more and 25% by mass or less.

[0050] The organic solvent preferably does not chemically react with hexamethylene diisocyanate or a hexamethylene diisocyanate derivative. Examples of the organic solvent include hydrocarbons, methyl ethyl ketone, acetone, ethyl acetate, butyl acetate, toluene, xylene, propylene glycol monomethyl ether acetate, diethylene glycol diethyl ether, dipropylene glycol monomethyl ether, and dipropylene glycol dimethyl ether.

[0051] Examples of hydrocarbons include pentane, hexane, heptane, octane, decane, petroleum ether, petroleum benzine, ligroin, petroleum spirit, cyclohexane, and methylcyclohexane.

[0052] When the wood protective coating is a topcoat or primer, one or both of components A and B may contain a coloring pigment, provided that the light transmittance is not excessively reduced. Examples of coloring pigments include titanium oxide, iron oxide, carbon black, quinacridone, and copper phthalocyanine.

[0053] When the wood protective coating is a primer, it is preferable that one or both of Agent A and Agent B contain an anti-algae and anti-fungal agent. When the primer contains an anti-algae and anti-fungal agent, it is possible to inhibit the growth of black mold on the surface of the wood even when the wood is used outdoors.

[0054] (1-7) Effects of wood protection paint Wood preservative paint can be applied to wood to form a coating film. The coating film has high light transmittance, making it easy to see the wood grain through the coating film. It also prevents changes in the color tone of the wood.

[0055] 2. Building exterior materials (2-1)Wood The building exterior components are made of wood. The species of wood is not limited. Examples of wood species include maple, birch, beech, oak, zelkova, apitong, ash, Shioji, elm, cypress, Japanese cypress, Japanese thunbergii, larch, Japanese larch, red pine, Japanese black pine, beihi, dahurica, larch, southern pine, Douglas fir, white cypress pine, western larch, hemlock, Alaska yellow cedar, red pine, radiata pine, western hemlock, fir, Abies sachalinensis, Siberian spruce, Bezos spruce, Bei fir, spruce, lodgepole pine, ponderosa pine, Scots pine, jack pine, lauan, Japanese cedar, and Japanese red cedar.

[0056] Cedar, western red cedar, and other woods with low density and large dimensional changes are not suitable for outdoor use. However, when the wood protective coating of the present disclosure is applied to form a coating film, dimensional changes can be suppressed even when used outdoors.

[0057] The density of each wood species is as follows. The numbers in parentheses indicate density. The unit of density is kg / m. 3 Cedar (340), fir (345), Sakhalin fir (385), cypress (408), Japanese cypress (425), red pine (420), spruce (430), Japanese kaya (445), larch (480), black pine (507), paulownia (275), sawagurumi (300), katsura (448), Japanese oak (530), chestnut (555), beech (580), sugar maple (600), zelkova (755), redwood (340), Scots pine (420), radiata pine (435), Douglas fir (490), balsa (97), rosewood (618).

[0058] The type of wood is not limited, and examples of the type of wood include lumber, plywood, laminated veneer lumber (LVL), glued laminated lumber, and cross-laminated timber (CLT). (2-2) Coating The building exterior member is provided with a coating film. The coating film is formed on wood. The coating film includes (c1) a reaction product of polycarbonate diol and hexamethylene diisocyanate or a hexamethylene diisocyanate derivative, (c2) an ultraviolet absorber, and (c3) a light stabilizer.

[0059] The polycarbonate diol, hexamethylene diisocyanate, hexamethylene diisocyanate derivative, UV absorber, and light stabilizer are as described in the section "1. Wood protective coating." A part or all of the coating film is formed, for example, by applying the wood protective coating of the present disclosure.

[0060] A 0.15mm thick coating film has a light transmittance of 19% or more at wavelengths of 650 to 750nm. The light transmittance at wavelengths of 650 to 750nm is preferably 40% or more. A light transmittance of 19% or more at wavelengths of 650 to 750nm makes it easy to see the wood grain through the coating film. A light transmittance of 80% or less at a wavelength of 400nm can suppress changes in appearance when the wood protective coating is applied to wood.

[0061] The coating film may be one layer or two or more layers. For example, the coating film may include a coating film formed by applying an undercoat paint and a coating film formed by applying a topcoat paint. (2-3) Effects of building exterior materials The coating film on building exterior components has high light transmittance, making it easy to see the wood grain through the coating film. It also helps prevent changes in the color tone of the wood.

[0062] 3. Working Example (3-1) Manufacturing of wood protection paints Wood protective coating materials of Examples 1 to 6 and Comparative Examples 1 to 4 were produced according to the formulations shown in Table 1.

[0063] [Table 1]

[0064] The wood protective coatings in each example and comparative example include a topcoat and a primer. The topcoat and primer each contain agent A and agent B. The blend amounts listed in Table 1 are in parts by mass. The compositions listed in Table 1 are non-volatile components. Agents A and B of the topcoat and primer contain a solvent in addition to the non-volatile components. The solvent is a mixed solvent of 80% by mass of ethyl acetate and 20% by mass of butyl acetate. The amount of solvent is 150 parts by mass for the topcoat and 70 parts by mass for the primer.

[0065] Polycarbonate diol 1 in Table 1 was synthesized from the following raw materials. Ethylene carbonate: 18 parts by mass 1,5-pentanediol: 10 parts by mass 1,6-hexanediol: 12 parts by mass Polycarbonate diol 2 in Table 1 was synthesized from the following raw materials.

[0066] Ethylene carbonate: 10 parts by mass 1,4-butanediol: 10 parts by mass 1,6-hexanediol: 1 part by mass The hexamethylene diisocyanate derivatives (biuret type) in Table 1 are those shown in Figure 1A. The hexamethylene diisocyanate derivatives (isocyanurate type) in Table 1 are those shown in Figure 1B.

[0067] The UV absorber in Table 1 was Tinuvin manufactured by BASF, which was a mixture of 2-[4-([2-hydroxy-3-dodecyloxypropyl)oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine and 2-[4-([2-hydroxy-3-tridecyloxypropyl)oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine in a mass ratio of 1:1.

[0068] The light stabilizers in Table 1 are bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate. (3-2) Manufacturing of building exterior components Cedar lumber was prepared as the wood. The dimensions of the wood were 10 mm thick, 70 mm wide, and 145 mm long. Using the wood protection coatings of each example and comparative example, building exterior components were manufactured in the following manner.

[0069] A mixed solution was prepared by mixing agent A and agent B of the primer paint. The mixed solution contained 100 parts by mass of the main component of agent A and 50 parts by mass of the hexamethylene diisocyanate derivative of agent B. The main components of agent A are polycarbonate diol 1, polycarbonate diol 2, polyether polyol, or alkyd resin.

[0070] Next, the mixed solution was diluted with ethyl acetate. Ethyl acetate corresponds to thinner for dilution. Next, the diluted mixed solution was applied to wood. The application method was two coats. The application amount of primer paint was the value shown in Table 1.

[0071] Next, the topcoat paint components A and B were mixed to prepare a mixed solution. The mixed solution contained 100 parts by mass of the main component of component A and 50 parts by mass of the hexamethylene diisocyanate derivative of component B. The main component of component A was polycarbonate diol 1, polycarbonate diol 2, or an alkyd resin.

[0072] Next, the mixed solution was diluted with butyl acetate. Butyl acetate corresponds to thinner for dilution. Next, the diluted mixed solution was applied on top of the primer paint film. The application method was one coat. The amount of top coat paint applied was the value shown in Table 1.

[0073] The total thickness of the primer paint film and the top coat paint film was 0.15 mm in each of the examples and comparative examples. (3-3) Evaluation of wood protection coatings and building exterior materials The wood grain was observed through the coating film. The visibility of the wood grain was evaluated according to the following criteria. The higher the light transmittance of the coating film, the better the visibility of the wood grain.

[0074] 〇: The wood grain is visible. ×: The wood grain cannot be seen. The evaluation results of the visibility of the wood grain are shown in Table 1.

[0075] A xenon accelerated weathering test was conducted. The test conditions were as follows: Light with a wavelength of 300 to 400 nm was irradiated onto the building exterior materials for 3,000 hours. The light irradiation intensity was 120 W / m 2 The building exterior members were visually observed before and after light irradiation. Weather resistance was evaluated according to the following criteria.

[0076] ◎: There is almost no difference before and after light irradiation. ○: There is a difference before and after light irradiation. However, the discoloration cannot be recognized by simply observing the test specimen after light irradiation.

[0077] △: There is a big difference before and after light irradiation. There is no abnormality in the coating film. ×: There is a large difference between before and after irradiation. Abnormalities such as swelling, peeling, and cracks have occurred in the coating film. The evaluation results of weather resistance are shown in Table 1.

[0078] For each of the examples and comparative examples, the light transmittance of the coating film was measured in the wavelength range of 300 to 800 nm. The measurement results are shown in Tables 2 and 3.

[0079] [Table 2]

[0080] [Table 3]

[0081] 4. Other Embodiments Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments and can be implemented in various modified forms.

[0082] (4-1) The function of one component in each of the above embodiments may be shared among multiple components, or the functions of multiple components may be performed by one component. Also, part of the configuration of each of the above embodiments may be omitted. Furthermore, at least part of the configuration of each of the above embodiments may be added to or substituted for the configuration of another of the above embodiments.

[0083] (4-2) In addition to the above-described architectural exterior components, the present disclosure can also be realized in various forms, such as a system including the architectural exterior components as components, a method for manufacturing architectural exterior components, and a method for manufacturing wood protective coatings.

Claims

1. A wood protection paint comprising: Contains agent A and agent B, The component A contains (a1) polycarbonate diol, (a2) an ultraviolet absorber, and (a3) ​​a light stabilizer, The agent B contains hexamethylene diisocyanate or a hexamethylene diisocyanate derivative, The coating film formed by the wood protective coating has a thickness of 0.15 mm and has a light transmittance of 19% or more at wavelengths of 650 to 750 nm and 80% or less at a wavelength of 400 nm. Wood protection paint.

2. The wood protective coating according to claim 1, The hexamethylene diisocyanate or the hexamethylene diisocyanate derivative is an isocyanurate type. Wood protection paint.

3. Wood and A coating film formed on the wood; A building exterior member comprising: The coating film comprises (c1) a reaction product of polycarbonate diol and hexamethylene diisocyanate or a hexamethylene diisocyanate derivative, (c2) an ultraviolet absorber, and (c3) a light stabilizer; The coating film having a thickness of 0.15 mm has a light transmittance of 19% or more at a wavelength of 650 to 750 nm and a light transmittance of 80% or less at a wavelength of 400 nm. Architectural exterior components.

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