JP2019058877A - Method for producing coat structure and building board - Google Patents

Abstract

To provide a method for producing a coat structure, wherein, when forming a second coat on a first coat from a water paint to produce the coat structure, a poor appearance of the second coat due to the first coat rejecting the water paint can be prevented.SOLUTION: After the surface of a first coat 2 is irradiated with electromagnetic waves, the surface of the first coat 2 is coated with a water paint to form a second coat 3, a coat structure 1 is produced.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for producing a coating structure and a building board, and more particularly to a method for producing a coating structure comprising a first coating and a second coating made of an aqueous paint, and the coating structure. For building boards.

  The article may be provided with a coating for the purpose of protection of the article, decoration and the like, and in this case, a plurality of coats may be provided in layers as needed.

  For example, in Patent Document 1, a colored coating film, a UV-cut silicone-based coating film having a refractive index of 1.50 to 1.60, and the like on the surface of a ceramic exterior material used as an outer wall material, roofing material, etc. It is described to provide a composite coating structure comprising a photocatalytic silicone based coating. In this composite coating structure, the UV-cut silicone coating can inhibit the arrival of ultraviolet rays to the pigmented coating, thereby preventing discoloration of the pigmented coating, and the photocatalytic silicone coating can have a self-cleaning function. It can be demonstrated.

Unexamined-Japanese-Patent No. 2007-136362

  When laminating a plurality of coatings, another coating (hereinafter, referred to as a second coating) is applied by applying an aqueous coating on one coating (hereinafter, referred to as a first coating) and then drying or curing the coating. When it is attempted to make it, the water-based paint tends to be repelled by the first film, which makes it difficult for the water-based paint to form a uniform film. For example, according to the technology disclosed in Patent Document 1, when an aqueous photocatalytic silicone-based coating agent is applied on an ultraviolet-cut silicone-based coating film to produce a photocatalytic silicone-based coating film, the ultraviolet-cut silicone resin is used. The coating film is easy to repel the photocatalytic silicone-based coating agent.

  For this reason, the coating film of the water-based paint is likely to have an uneven thickness called a twist, and as a result, the second coating may have appearance defects such as uneven gloss and glare. This leads to a reduction in yield when the article is provided with the first film and the second film to produce the product.

  The object of the present invention is to prepare a second coating from an aqueous coating on a first coating to produce a coating composition, wherein the first coating is caused by repelling the aqueous coating. An object of the present invention is to provide a method for producing a coating composition capable of suppressing appearance defects.

  In the method for producing a coating composition according to the first aspect of the present invention, after the surface of the first coating is irradiated with electromagnetic waves, an aqueous paint is applied to the surface of the first coating to produce a second coating. Do.

  In the second aspect of the present invention, in the first aspect, the wavelength of the electromagnetic wave is 200 nm or less.

  In the third aspect of the present invention, in the first or second aspect, the first film is made of an inorganic paint or a fluorine resin paint.

  In the fourth aspect of the present invention, in the first to third aspects, the first coating is formed on the surface of the undercoat.

  In the fifth aspect of the present invention, in the first to fourth aspects, the water-based paint contains a photocatalyst.

  The building board according to the sixth aspect of the present invention includes the coated structure manufactured by the method of manufacturing a coated structure according to any one of the first to fifth aspects.

  According to a first aspect of the present invention, in producing a coating composition comprising a first coating and a second coating produced from an aqueous coating, the second coating is caused by repelling the aqueous coating. There is an advantage that the appearance defect of the second film can be suppressed.

It is a schematic sectional drawing which shows the coating film structure and a building board in one Embodiment of this invention.

  Hereinafter, an embodiment of the present invention will be described. FIG. 1 shows a coating structure 1 according to this embodiment and a building board 6 provided with the coating structure 1.

  In the present embodiment, a coated structure 1 including the first film 2 and the second film 3 is manufactured. In the present embodiment, after the surface of the first film 2 is irradiated with electromagnetic waves, an aqueous paint is applied to the surface of the first film 2 to produce the second film 3. In this case, by irradiating the first coating 2 with an electromagnetic wave, even if the first coating 2 is coated with the aqueous coating, the first coating 2 is less likely to repel the aqueous coating. Therefore, the coating film made of the water-based paint is less likely to cause uneven thickness called a twist. As a result, appearance defects such as gloss unevenness and glare are less likely to occur in the second film 3.

  The reason why the effect of the present embodiment can be obtained is presumed to be as follows. When the first coating 2 is irradiated with an electromagnetic wave, the surface of the first coating 2 is roughened. Furthermore, the bond between atoms in the first film 2 is broken by the electromagnetic wave, whereby the surface free energy of the first film 2 is increased. As a result, it is considered that the wettability to the water of the surface of the first coating 2 is enhanced.

  Hereinafter, the case where the construction board 6 provided with the film structure 1 is manufactured is mentioned as an example, and the detail of this embodiment is further demonstrated.

  The building board 6 is used, for example, as an outer wall material or a roof material. The building board 6 includes, for example, a base material 5, an undercoat film 4, a first film 2 and a second film 3, which are laminated in this order. Among these, the first coating 2 and the second coating 3 constitute the coating composition 1. By providing the coating structure 1, the building board 6 is less likely to have an appearance defect such as uneven gloss and glare on its surface.

  The substrate 5 is made of ceramic material such as cement.

  The undercoat film 4 is made of, for example, a coating agent containing an organic resin such as an acrylic resin and a pigment. The undercoat film 4 is provided, for example, for the protection of the substrate 5 or for further coloring the building board 6 to enhance its design.

  The first film 2 is preferably made of an inorganic paint or a fluorine resin paint. When the first film 2 is produced from an inorganic paint or a fluorocarbon resin paint, the first film 2 inherently tends to repel water. However, when the electromagnetic wave is irradiated to the first film 2 made of the inorganic paint or the fluorine resin paint, the wettability of the surface of the first film 2 to water can be greatly improved. Therefore, when the first film 2 is made of an inorganic paint or a fluorine resin paint, the effects of the present embodiment can be remarkably obtained.

  The fluororesin-based paint may be a paint that is generally commercially available. A publicly known method can be adopted as a method of producing the first film 2 from the fluororesin-based paint.

  The inorganic paint is, for example, a polyorganosiloxane paint. The inorganic paint contains, for example, an organosila oligomer having a hydrolyzable group, silica, a polyorganosiloxane having a silanol group and a catalyst, and is substantially free of water. The inorganic paint is, for example, an organic solvent solution containing organosilane oligomers having hydrolyzable groups and silica (hereinafter also referred to as component (A)), an organic solvent solution of polyorganosiloxanes having silanol groups (hereinafter, It is prepared by mixing B) component (also referred to as component B) and a catalyst (hereinafter also referred to as component C).

  The component (A) will be described. The component (A) is prepared, for example, by partially hydrolyzing the hydrolyzable organosilane in a reaction solution containing the hydrolyzable organosilane and colloidal silica. The hydrolyzable organosilane is represented, for example, by the following general formula (I).

R ¹ SiX _4-n (I)
R ¹ in the formula (I) is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms, n is an integer of 0 to 3, and X is a hydrolyzable group.

R ¹ in the formula (I) is, for example, an alkyl group such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group and octyl group; cycloalkyl group such as cyclopentyl group and cyclohexyl group; Aralkyl groups such as phenylethyl group, 2-phenylpropyl group and 3-phenylpropyl group; aryl groups such as phenyl group and tolyl group; alkenyl groups such as vinyl group and allyl group; chloromethyl group, γ-chloropropyl group, 3, 3 Or a halogen-substituted hydrocarbon group such as a 3-trifluoropropyl group; or a substituted hydrocarbon group such as a γ-methacryloxypropyl group, a γ-glycidoxypropyl group, a 3,4-epoxycyclohexylethyl group or a γ-mercaptopropyl group is there. In order to make it easy to obtain the hydrolyzable organosilane and to facilitate the preparation of the component (A), R ¹ is preferably an alkyl group having 1 to 4 carbon atoms or a phenyl group.

  X in the formula (I) contains, for example, at least one group selected from the group consisting of an alkoxy group, an acetoxy group, an oxyl group, an enoxy group, an amino group, an aminoxy group, and an amido group. In order to facilitate the availability of hydrolyzable organosilanes and to facilitate the preparation of the component (A), X preferably contains an alkoxy group.

  The hydrolyzable organosilane can include compounds of mono-, di-, tri- and tetra-functionality where n in the formula (I) is an integer of 0-3. Hydrolyzable organosilanes include, for example, alkoxysilanes, acetoxysilanes, oximesilanes, enoxysilanes, aminosilanes, aminoxysilanes, and amidosilanes. In order to make it easy to obtain hydrolyzable organosilane and to facilitate preparation of component (A), the hydrolyzable organosilane preferably contains alkoxysilanes.

  Examples of tetralkoxysilanes where n = 0 include tetramethoxysilane and tetraethoxysilane. Examples of organotrialkoxysilanes for n = 1 are methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, and 3,3,3-trifluoropropyltrimethoxy Contains silane. Examples of n = 2 diorganodialkoxysilanes include dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, and methylphenyldimethoxysilane. Examples of n = 3 triorganoalkoxysilanes include trimethylmethoxysilane, trimethylethoxysilane, trimethylisopropoxysilane, and dimethyl isobutyl methoxysilane. Examples of alkoxysilanes also include organosilane compounds commonly referred to as silane coupling agents.

  The hydrolyzable organosilane comprises a trifunctional component in which n is 1 in formula (I), and the amount of trifunctional component with respect to the total hydrolysable organosilane is 50 mol% or more, preferable. In this case, a sufficiently high curability of the inorganic coating can be obtained, and a sufficient hardness of the first coating 2 can be obtained. The amount of the trifunctional component is more preferably 60 mol% or more, and most preferably 70 mol% or more.

  The silica in the component (A) can increase the hardness of the first coating 2. The dispersion medium of colloidal silica, which is a raw material for silica, may be water or a non-aqueous organic solvent such as alcohol. Colloidal silica contains, for example, 20 to 50% by mass of silica. The organic solvent preferably comprises a hydrophilic organic solvent, and the hydrophilic organic solvent is, for example, lower aliphatic alcohols such as methanol, ethanol, isopropanol, n-butanol and isobutanol; ethylene glycol, ethylene glycol monobutyl ether, ethylene glycol monoacetate Ethylene glycol derivatives such as ethyl ether; diethylene glycol, derivatives of diethylene glycol such as diethylene glycol monobutyl ether; and at least one component selected from the group consisting of diacetone alcohol. The organic solvent may also contain, in addition to the hydrophilic organic solvent, at least one component selected from the group consisting of toluene, xylene, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone and methyl ethyl ketoxime.

  It is preferable that the quantity of colloidal silica with respect to the whole reaction solution at the time of preparation of (A) component exists in the range of 5-95 mass%. When the amount of colloidal silica is 5% by mass or more, sufficient hardness of the first film 2 is obtained, and when the amount is 95% by mass or less, good dispersibility of silica in the component (A) is obtained Be The amount of colloidal silica is more preferably in the range of 10 to 90% by mass, and further preferably in the range of 20 to 85% by mass.

  In order to prepare the component (A), for example, a hydrolyzable organosilane and colloidal silica are first mixed to obtain a reaction solution. A catalyst is added to the reaction solution as needed. The catalyst can include one or both of organic and inorganic acids. More specifically, the catalyst is, for example, hydrochloric acid, acetic acid, halogenated silane, chloroacetic acid, citric acid, benzoic acid, dimethylmalonic acid, formic acid, propionic acid, glutanic acid, glycolic acid, maleic acid, malonic acid, toluene sulfone An acid and at least one component selected from the group consisting of oxalic acid.

  The reaction solution contains water for partial hydrolysis of the hydrolyzable organosilane. The amount of water is preferably in the range of 0.001 to 0.5 mol based on 1 mol of X in formula (I) of the hydrolyzable organosilane. Partial hydrolysis can be sufficiently proceeded when the amount of water is 0.001 mol or more, and good stability of the partial hydrolyzate can be obtained when the amount of water is 0.5 mol or less . The water may be water in colloidal silica or water separately added to the reaction solution.

  In the reaction solution, partial hydrolysis of the hydrolyzable organosilane proceeds. While the partial hydrolysis is in progress, the reaction solution may be kept at normal temperature, or the reaction solution may be heated to, for example, 60 to 100 ° C. to promote partial hydrolysis.

  The pH of the component (A) is preferably in the range of 2.0 to 7.0. In this case, the performance deterioration of the component (A) with time can be suppressed. The pH is more preferably in the range of 2.5 to 6.5, and still more preferably in the range of 3.0 to 6.0. The adjustment of the pH of the component (A) can be performed, for example, by adding an appropriate acidic substance or basic substance to the component (A). Examples of acidic substances include hydrochloric acid, nitric acid and acetic acid, and examples of basic substances include ammonia and ethylene diamine.

  The component (B) will be described. The polyorganosiloxane having a silanol group in the component (B) is represented, for example, by the following average composition formula (II).

R ² _a Si (OH) _b O _{(4-ab) / 2} (II)
In the formula (II), R ² is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms, and when R ² is plural, they may be the same or different from each other, and a and b are 0 2 ≦ a ≦ 2, 0.0001 ≦ b ≦ 3, and a + b <4.

Examples of R ^{2 in} the formula (II) are the same as the examples of R ¹ in the above (I). R ² represents an alkyl group having 1 to 4 carbon atoms, a phenyl group, a vinyl group, a γ-glycidoxypropyl group, a γ-methacryloxypropyl group, a γ-aminopropyl group, and 3,3,3-trifluoropropyl It is preferable to include at least one group selected from the group consisting of groups, and it is particularly preferable to include one or both of a methyl group and a phenyl group.

  The crack of the first film 2 can be suppressed when a in the formula (II) is 0.2 or more and b is 3 or less. When a is 2 or less, b is 0.0001 or more, and a + b is less than 4, good curability of the inorganic paint is obtained.

  Polyorganosiloxanes having silanol groups, for example, at least one component selected from the group consisting of methyltrichlorosilane, dimethyldichlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, and alkoxysilanes thereof in a large amount by a known method It is obtained by hydrolysis with water.

  The component (C) promotes the condensation reaction of the components (A) and (B) to promote the curing of the inorganic coating. Component (C) is, for example, metal salts of carboxylic acids such as alkyl titanates, tin octylate, dibutyltin dilaurate, dioctyltin dimaleate; amine salts such as dibutylamine-2-hexoate, dimethylamine acetate, ethanolamine acetate; Carboxylic acid quaternary ammonium salts such as methyl ammonium; amines such as tetraethylpentamine; amines such as N-β-aminoethyl-γ-aminopropyltrimethoxysilane, N-β-aminoethyl-γ-aminopropylmethyldimethoxysilane Silane coupling agents; p-toluenesulfonic acid, phthalic acid, acids such as hydrochloric acid; aluminum alkoxides, aluminum compounds such as aluminum chelate; alkali catalysts such as potassium hydroxide; Including and methyltrichlorosilane, dimethyldichlorosilane, at least one component selected from the group consisting of halogenated silane such as trimethyl monochloro silane; isopropyl titanate, tetrabutyl titanate, titanium compounds such as titanium tetra acetylacetonate.

  It is preferable that the quantity of (A) component exists in the range of 1-99 mass parts with respect to 100 mass parts of total amounts of (A) component and (B) component in a reaction solution. When the amount of the component (A) is 1 part by mass or more, sufficiently high curability of the inorganic coating can be obtained even at normal temperature, and sufficient hardness of the first film 2 can be obtained. When the amount of the component (A) is 99 parts by mass or less, stable curability of the inorganic coating material and good characteristics of the first film 2 can be obtained. The amount of the component (A) is more preferably in the range of 5 to 95 parts by mass, and further preferably in the range of 10 to 90 parts by mass.

  The amount of the component (C) is preferably in the range of 0.0001 to 10 parts by mass with respect to 100 parts by mass in total of the components (A) and (B). When the amount of the component (C) is 0.0001 parts by mass or more, sufficiently high curability of the inorganic coating is obtained even at normal temperature, and when the amount is 10 parts by mass or less, the first film 2 has good heat resistance and It can have weatherability. The amount of the component (C) is more preferably in the range of 0.0005 to 8 parts by mass, and still more preferably in the range of 0.0007 to 5 parts by mass.

  In addition to (A) component, (B) component, and (C) component, you may mix | blend an organic solvent with an inorganic type coating material. The example of the organic solvent is the same as the example of the organic solvent which is the dispersion medium of the above-mentioned colloidal silica.

  The inorganic paint may contain an ultraviolet absorber. In this case, deterioration of the undercoat film 4 is suppressed by the first film 2 shielding ultraviolet light. Examples of UV absorbers include zinc oxide particles. The amount of the ultraviolet light absorber is preferably in the range of 0.1 to 50% by mass with respect to the dry solid content (the total amount excluding the solvent) of the inorganic coating material.

  The inorganic paint may contain a matting agent. The matting agent is a component that reduces the gloss of the first film 2 by, for example, diffusing and reflecting light. The matting agent comprises metal oxide particles, for example silica particles. The particle diameter of the metal oxide particles is preferably in the range of 1 to 50 μm. The amount of the metal oxide particles is preferably in the range of 1 to 20% by mass with respect to the dry solid content (the total amount excluding the solvent) of the inorganic coating material.

  An inorganic paint is applied on undercoat film 4 and the like, and the hydrolyzable group of the organosila oligomer in the inorganic paint and the silanol group of the polyorganosiloxane are condensed at normal temperature or under heating at, for example, 100 ° C. or less. The first film 2 can be produced by reaction.

  The water-based paint will be described. The water-based paint is, for example, a silicone-based paint. The aqueous paint contains, for example, a partial hydrolysis condensate of an alkoxysilane.

  The alkoxysilane is represented by the following general formula [1].

R ² _n Si (OR ¹ ) _4-n [1]
In Formula [1], n is a number of 0-3. That is, the alkoxysilane contains at least one component selected from the group consisting of, for example, tetraalkoxysilane, organotrialkoxysilane, diorganodialkoxysilane and triorganoalkoxysilane. In formula [1], each of R ¹ and R ² is a monovalent hydrocarbon group. A plurality of R ¹ when R ¹ is a plurality in one molecule may be heterologous even the same species together. When there are a plurality of R ^{2 in} one molecule, the plurality of R ¹ may be the same or different from each other.

R ¹ is, for example, an alkyl group having 1 to 4 carbon atoms.

R ² is, for example, a substituted or unsubstituted hydrocarbon group having 1 to 8 carbon atoms. R ² is, for example, an alkyl group such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group and octyl group; cycloalkyl group such as cyclopentyl group and cyclohexyl group, 2-phenylethyl group, 3 Aralkyl groups such as -phenylpropyl group; aryl groups such as phenyl group and tolyl group, anikenyl groups such as vinyl group and allyl group; halogen substituted carbonization such as chloromethyl group, γ-chloropropyl group and 3,3,3-trifluoropropyl group And at least one group selected from the group consisting of hydrogen, and substituted hydrocarbon groups such as γ-methacryloxypropyl, γ-glycidoxypropyl, 3,4-epoxycyclohexylethyl and γ-mercaptopropyl. Including. In order to facilitate synthesis or availability of the alkoxysilane, R ² preferably contains at least one group selected from the group consisting of an alkyl group having 1 to 4 carbon atoms and a phenyl group.

  When the alkoxysilane includes a tetraalkoxysilane represented by the following general formula [2], the tetraalkoxysilane includes, for example, one or both of tetramethoxysilane and tetraethoxysilane.

Si (OR ¹ ) ₄ [2]
When the alkoxysilane contains an organotrialkoxysilane represented by the following general formula [3], the organotrialkoxysilane is, for example, methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, phenyltrimethoxysilane, phenyl And at least one component selected from the group consisting of triethoxysilane and 3,3,3-trifluoropropyltrimethoxysilane.

R ² Si (OR ¹ ) ₃ [3]
When the alkoxysilane includes a diorganodialkoxysilane represented by the following general formula [4], the diorganodialkoxysilane is, for example, dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane and methylphenyl. It contains at least one component selected from the group consisting of dimethoxysilane.

R ² ₂ Si (OR ¹ ) ₂ [4]
When the alkoxysilane comprises a triorganoalkoxysilane, the triorganoalkoxysilane comprises at least one component selected from the group consisting of, for example, trimethylmethoxysilane, trimethylethoxysilane, trimethylisopropoxysilane and dimethylisobutylmethoxysilane.

  In order to obtain a partially hydrolytic condensation polymer of alkoxysilane, in particular, a mixture containing one or both of tetraalkoxysilane and silica and an organotrialkoxysilane, or further containing a diorganodialkoxysilane In particular, partial hydrolysis and condensation polymerization of alkoxysilane is preferable.

  When the mixture contains silica, the silica is preferably incorporated into the mixture in the form of colloidal silica. Colloidal silica contains silica and an organic solvent which is a dispersion medium. The amount of silica in the colloidal silica is, for example, in the range of 20 to 50% by mass. The organic solvent includes, for example, a hydrophilic organic solvent, and the hydrophilic organic solvent includes, for example, lower aliphatic alcohols such as methanol, ethanol, isopropanol, n-butanol and isobutanol; ethylene glycol, ethylene glycol monobutyl ether, acetic acid ethylene glycol monoethyl ether And at least one component selected from the group consisting of diethylene glycol, derivatives of diethylene glycol such as diethylene glycol monobutyl ether; and diacetone alcohol. The organic solvent may further contain, in addition to the hydrophilic organic solvent, at least one component selected from the group consisting of toluene, xylene, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone and methyl ethyl ketoxime.

  In the mixture, the total amount of tetraalkoxysilane and silica is in the range of 20 to 200 parts by weight, the amount of trialkoxysilane is 100 parts by mass, and the amount of dialkoxysilane is in the range of 0 to 60 parts by weight Is preferred.

  Add water to the mixture. The amount of water in the mixture is preferably 45% by weight or less, more preferably 25% by weight or less.

  A catalyst is added to the mixture as needed. Also, an organic solvent is added to the mixture as needed. The organic solvent includes, for example, a hydrophilic organic solvent, and the hydrophilic organic solvent includes, for example, lower aliphatic alcohols such as methanol, ethanol, isopropanol, n-butanol and isobutanol; ethylene glycol, ethylene glycol monobutyl ether, acetic acid ethylene glycol monoethyl ether And at least one component selected from the group consisting of diethylene glycol, derivatives of diethylene glycol such as diethylene glycol monobutyl ether; and diacetone alcohol. The organic solvent may further contain, in addition to the hydrophilic organic solvent, at least one component selected from the group consisting of toluene, xylene, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone and methyl ethyl ketoxime.

  The weight average molecular weight of the partially hydrolyzed and polymerized product of alkoxysilane measured by gel permeation chromatography is preferably 900 or more in terms of polystyrene. In this case, it is possible to suppress an excessive curing shrinkage in the case of producing the second film 3 by curing the water-based paint, and to suppress the cracks in the second film 3.

  The partial hydrolysis condensate of alkoxysilane is obtained by partially hydrolyzing alkoxysilane. The alkoxysilane may be partially hydrolyzed in a system in which the alkoxysilane and the silica coexist, and in this case, the aqueous coating contains the partially hydrolyzed condensate of the alkoxysilane and the silica.

  The pH of the aqueous paint is preferably in the range of 3.8 to 6. In this case, the preservation of the water-based paint is good. Adjustment of pH can be performed, for example, by adding an appropriate acidic substance or basic substance to an aqueous paint. Examples of acidic substances include hydrochloric acid, nitric acid and acetic acid, and examples of basic substances include ammonia and ethylene diamine. In the case of partially hydrolytic condensation polymerization of alkoxysilanes in the mixture, if the reaction does not proceed sufficiently within the pH range of 3.8 to 6, the mixture may be heated to promote the reaction The pH of the mixture may be lowered to promote the reaction, and then the basic substance may be added to raise the pH.

  The water-based paint may contain a photocatalyst. That is, the second film 3 may contain a photocatalyst. In this case, even if the contaminant adheres to the second film 3, the contaminant may be decomposed by photocatalysis when the second film 3 is irradiated with light. For this reason, the coating composition 1 and the building board 6 can be provided with contamination resistance.

  When the water-based paint contains a photocatalyst, the photocatalyst is, for example, titanium oxide, zinc oxide, tin oxide, iron oxide, zirconium oxide, tungsten oxide, chromium oxide, molybdenum oxide, molybdenum oxide, ruthenium oxide, germanium oxide, lead oxide, cadmium oxide, copper oxide And at least one component selected from the group consisting of vanadium oxide, niobium oxide, tantalum oxide, manganese oxide, cobalt oxide, rhodium oxide and rhenium oxide. Preferably, the photocatalyst comprises titanium oxide. The amount of the photocatalyst is preferably in the range of 10 to 90% by mass, and more preferably in the range of 30 to 70% by mass, with respect to the solid content in the aqueous paint.

  In order to manufacture the coating structure 1 and the building board 6 including the same, for example, the base material 5 is first applied with a primer coating if necessary, and then a coating agent is applied. The coating method is, for example, a spray method, a roll coater or a flow coater, but is not limited thereto. The primer film 4 is produced by drying or curing this coating agent as required. The thickness of the undercoat 4 is, for example, in the range of 3 to 60 μm.

  Next, the undercoat film 4 is coated with a paint such as an inorganic paint for the first film 2 or a fluorine resin paint. The coating method is, for example, a spray method, a roll coater or a flow coater, but is not limited thereto. The first coating 2 is produced by drying or curing this paint as required. The thickness of the first film 2 is, for example, in the range of 1 to 10 μm.

  Next, the first film 2 is irradiated with an electromagnetic wave. The wavelength and irradiation amount of the electromagnetic wave are set so that the wettability of the first film 2 to water can be effectively improved. In particular, the wavelength of the electromagnetic wave is preferably 200 nm or less. In this case, the surface free energy of the first coating 2 is likely to be particularly large, and the wettability of the first coating 2 to water is thus likely to be enhanced. More preferably, the wavelength of the electromagnetic wave is in the range of 100 to 200 nm.

  Next, a water-based paint is applied to the first film 2. The coating method is, for example, a spray method, a roll coater or a flow coater, but is not limited thereto. At the time of this coating, the wettability of the surface of the first film 2 with water is enhanced by the irradiation of the above-mentioned electromagnetic waves, so the water-based paint is hardly repelled by the surface of the first film 2. For this reason, it is hard to produce the nonuniformity of the thickness called yori in the coating film of water-based paint. The second coating 3 is produced by drying or curing this coating as required. As described above, since the coating film is less likely to be distorted, the second film 3 is less likely to have an appearance defect such as uneven gloss and glare. The thickness of the second film 3 is, for example, in the range of 0.05 to 1 μm.

  Thereby, the coating composition 1 provided with the first coating 2 and the second coating 3 and the building board 6 provided with the coating composition 1 can be obtained.

  The refractive index of the first film 2 is preferably in the range of 1.50 to 1.60. In this case, even if the second film 3 has a high refractive index by including a photocatalyst, the reflection of light in the film structure 1 can be suppressed, and the gloss of the film structure 1 can be suppressed low. In order for the refractive index of the first coating 2 to be in the range of 1.50 to 1.60, it is preferable that the first coating 2 and the paint therefor contain high refractive index particles. The high refractive index particles are, for example, titanium oxide particles (refractive index 2.4 to 2.7), aluminum oxide particles (refractive index 1.8), zinc oxide particles (refractive index 1.9 to 2.0), and zirconium oxide It contains at least one component selected from the group consisting of particles (refractive index 2.0). It is particularly preferred that the high refractive index particles contain zinc oxide particles. Since zinc oxide particles are also UV absorbers, zinc oxide particles can simultaneously achieve UV shielding in the first coating 2 and an increase in the refractive index of the first coating 2.

  The refractive index of the second film 3 is preferably in the range of 1.60 to 1.75. In this case, the difference in refractive index between the second coating 3 and the first coating 2 can be reduced to particularly suppress the reflection of light in the coating composition 1. Setting the refractive index of the second film 3 within the above range means, for example, the amount of the aqueous paint and the photocatalyst in the second film 3 in such a range that the second film 3 has sufficiently high photocatalytic activity. It can be realized by adjusting.

  The haze of the coating structure 1 is preferably in the range of 5.0 to 20.0%. When the haze is 5.0% or more, the gloss of the coating 1 can be sufficiently suppressed, and when the haze is 20.0% or less, the undercoat 4 can be easily visually recognized from the outside through the coating 1. When the haze is within the above range, for example, the first coating 2 may contain particles having light scattering properties, and the first coating 2 may not be completely cured. The application of the water-based paint can be realized by a method which does not produce a clear interface between the first film 2 and the second film 3. The particles having light scattering properties are, for example, silica particles (refractive index 1.45), aluminum oxide particles (refractive index 1.8), titanium oxide particles (refractive index 2.4 to 2.7), ITO particles (refractive index 1.9 to 2.0), ATO particles (refractive index 1.9 to 2.0), metal oxide particles such as zirconium oxide particles (refractive index 2.0), and methyl silicone particles (refractive index 1.45 to 50) And at least one component selected from the group consisting of 1.50). The particle size of the light scattering particles is preferably 50 μm or less. In this case, it is possible to suppress an excessive increase in the haze of the coating structure 1. The particle size of the light scattering particles is more preferably 20 μm or less. It is also preferable that the particle diameter of the light scattering particles is 1 μm or more, and in this case, the light scattering particles can have sufficiently high light scattering characteristics.

1. Preparation of Inorganic Coating In a flask equipped with a stirrer, a heating jacket, a condenser and a thermometer, methanol dispersed colloidal silica sol (particle diameter 10 to 20 nm, solid content 30% by mass, moisture 0.5% by mass: Nissan Chemical Industries, Ltd. A mixed solution was prepared by adding 100 parts by mass of product name MT-ST, 68 parts by mass of methylmethoxysilane, and 10.8 parts by mass of water. The mixture was kept at 65 ° C. for about 5 hours with stirring, then cooled to room temperature and subsequently left at room temperature for 48 hours. Thereby, (A) component of solid content 36 mass% was obtained.

  Further, 1000 parts by mass of water and 50 parts by mass of acetone were added to a flask equipped with a stirrer, a heating jacket, a condenser, a dropping funnel and a thermometer to obtain a mixed solution. While stirring the mixture at 60 ° C., a solution obtained by mixing 149.3 parts by mass of methyltrichlorosilane and 200 parts by mass of toluene was dropped into the mixture. Stirring was stopped 40 minutes after the end of the dropwise addition. Next, the mixture was transferred into a separatory funnel and allowed to stand to separate it into two phases. Of the two phases, the lower phase was drained from the separatory funnel, and the remaining phase, from the remaining phase, the water and hydrochloric acid remaining in this phase, was stripped with an excess of toluene by vacuum stripping. As a result, a 60 mass% toluene solution of silanol-containing polyorganosiloxane was obtained as the component (B).

  50 parts by mass of the component (A) and 50 parts by mass of the component (B) were mixed to obtain a solution. While stirring this solution, 25 parts by mass of silicone paint-dispersed zinc oxide (particle diameter 10 to 200 nm, solid content 32% by weight: manufactured by Sakai Chemical Co., Ltd.) was dropped to this solution. Further, 2 parts by mass of N-β-aminoethyl-aminopropylmethyldimethoxysilane as a catalyst is added to this solution, and then the solution is diluted with isopropyl alcohol to a solid content concentration of 20% by mass to obtain an inorganic substance. I got a paint base.

2-1. Preparation of water-based paint A 20 parts by mass of silica sol containing silica with an average primary particle diameter of 10 to 20 nm at a concentration of 3.6% by mass, and tetraethoxysilane to isopropyl alcohol so that the concentration of tetraethoxysilane is 1.9% by mass The resulting solution was mixed with 6 parts by mass of the solution to obtain a solution. An aqueous paint A was prepared by adding 74 parts by mass of deionized water whose surface tension was adjusted to 28 to 30 mN / m with a surfactant.

  The surface tension of the water-based paint A was 28 mN / m as a result of measurement by the hanging drop method using Young-Laplace's equation.

2-2. Preparation of water-based paint B 20 parts by mass of silica sol containing silica with an average primary particle diameter of 10 to 20 nm at a concentration of 3.6% by mass, tetraethoxysilane to isopropyl alcohol so that the concentration of tetraethoxysilane is 1.9% by mass The solution was mixed with 6 parts by mass of the solution obtained to give a solution. An aqueous paint B was prepared by adding 74 parts by mass of ion exchanged water having a surface tension of 71 to 73 mN / m to this solution.

  The surface tension of the water-based paint B was measured by the hanging drop method using Young-Laplace's equation, which was 42 mN / m.

3. Preparation of undercoat film and first film A coating agent (manufactured by Kansai Paint Co., Ltd., product name IM coat 4100, straight gray color) is applied to float glass (refractive index 1.53) having a thickness of 2 mm, and the dry film thickness is about 30 μm by a spray method. The primer coating was prepared by applying the coating to a thickness of 20 μm and curing at room temperature sufficiently and then heating at 120 ° C. for 20 minutes.

  An inorganic paint was applied to the undercoat film by a spray method, and after sufficiently curing at room temperature, heating was performed at 120 ° C. for 20 minutes to prepare a first film having a thickness of about 10 μm.

4-1. Comparative Example 1
The first film was not irradiated with electromagnetic waves. The result of measuring the static contact angle of this first film with water was 92 °. In addition, the result of measuring the static contact angle of the first coating with the above-mentioned water-based paint A was 45 °.

  The above-mentioned water-based paint A is applied to the first film by a spray method to form a film, and the film is sufficiently cured at room temperature and then heated at 120 ° C. for 20 minutes to have a thickness of 0.1 μm. A second coating was made.

  When the appearance of the coating film of the water-based paint A was observed when producing the second film, it was observed that a twist was observed.

4-2. Comparative example 2
The first film was not irradiated with electromagnetic waves. The result of measuring the static contact angle of the first coating with the above-mentioned water-based paint B was 79 °.

  The above-mentioned water-based paint B is applied to the first film by a spray method to form a film, and the film is sufficiently cured at room temperature and then heated at 120 ° C. for 20 minutes to obtain a thickness of 0.1 μm. A second coating was made.

  When the appearance of the coating of the water-based paint B was observed when producing the second coating, it was observed that a twist was observed.

4-3. Example 1
The first film was irradiated with an electromagnetic wave having a wavelength of 172 nm. The electromagnetic wave source (light source) at this time is a xenon lamp, the distance from the light source to the undercoat is 5 mm, the irradiation time is 180 seconds, and the accumulated irradiation amount is 0.1 J / m ² .

  The result of measuring the static contact angle with water of the first coating after electromagnetic wave irradiation was 26 °. Moreover, the result of having measured the static contact angle with said water-based paint A of the 1st film after electromagnetic wave irradiation was 5 degrees.

  The above-mentioned water-based paint A is applied by spray method to the first film after electromagnetic wave irradiation in the same manner as in Comparative Example 1 to form a coating film, and this coating film is sufficiently cured at room temperature 20 By heating for a minute, a second coating having a thickness of 0.1 μm was produced.

  When the appearance of the coating of the water-based paint A was observed when producing the second film, no twist was observed.

4-4. Example 2
The first film was irradiated with an electromagnetic wave under the same conditions as in Example 1.

  The result of measuring the static contact angle with water of the first coating after electromagnetic wave irradiation was 26 ° as in Example 1. Moreover, the result of having measured the static contact angle with said water-based coating material B of the 1st film after electromagnetic wave irradiation was 5 degrees.

  The above-mentioned water-based paint A is applied by spray method to the first film after electromagnetic wave irradiation in the same manner as in Comparative Example 2 to form a coating film, and the coating film is sufficiently cured at room temperature 20 By heating for a minute, a second coating having a thickness of 0.1 μm was produced.

  When the appearance of the coating of the water-based paint B was observed when producing the second film, no twist was observed.

  The conditions and evaluations of the above Comparative Examples 1 and 2 and Examples 1 and 2 are summarized in the following table.

1 Coating Composition 2 First Coating 3 Second Coating 4 Primer Coating 5 Base Material 6 Building Board

Claims (6)

After irradiating the surface of the first film with an electromagnetic wave,
A method of producing a coating composition, comprising applying an aqueous paint on the surface of the first coating to produce a second coating. In claim 1,
The manufacturing method of the film structure whose wavelength of the said electromagnetic waves is 200 nm or less. In claim 1 or 2,
The method for producing a coated structure wherein the first film is made of an inorganic paint or a fluorocarbon resin paint. In any one of claims 1 to 3,
A method of producing a coating composition, wherein the first coating is produced on the surface of a primer coating. In any one of claims 1 to 4,
The method for producing a coating composition, wherein the aqueous paint contains a photocatalyst. A building board provided with the film structure manufactured with the manufacturing method according to any one of claims 1 to 5.