JP2007167718A - Coating body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating body capable of enhancing durability by enhancing an adhesion property of an inorganic coating film and a photocatalyst-containing inorganic coating film, and enhancing an contamination-proofing property. <P>SOLUTION: The present invention relates to the coating body in which the coating films are formed on a surface of a base material 1 of a ceramic industry system in the order of an organic coating film 2, the inorganic coating film 3 and the photocatalyst-containing inorganic coating film 4. A contact area of the inorganic coating film 3 and the photocatalyst-containing inorganic coating film 4 is increased by setting a surface roughness Ra of the inorganic coating film 3 to 0.2-3 μm and the adhesion property of the inorganic coating film and the photocatalyst-containing inorganic coating film can be enhanced. Recession/projection receiving the surface roughness of the inorganic coating film 3 is formed on a surface of the photocatalyst-containing inorganic coating film 4, a surface area of the photocatalyst-containing inorganic coating film 4 becomes large and a photocatalyst effect can be obtained at a higher degree. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a coated body formed by providing a ceramic base material with a coating film such as a cement exterior material.

  The surface of the cement-based ceramic base material 1 used as an outer wall material or the like is colored for its makeup. This colored coating is usually carried out by coating an organic coating agent containing a pigment or the like to form the organic coating film 2. However, since this organic coating film 2 is organic, it deteriorates due to the action of ultraviolet rays. , Fading easily occurs.

  Therefore, as shown in FIG. 1, in order to protect the organic coating film 2, a silicone-based inorganic coating film 3 is formed as a clear topcoat. Since the inorganic coating film 3 is inorganic, the organic coating film 2 can be protected from ultraviolet rays because the inorganic coating film 3 is hardly deteriorated against ultraviolet rays and hardly transmits ultraviolet rays. In particular, the organic coating film 2 can be more effectively protected by blending an ultraviolet absorber to make the inorganic coating film 3 have an ultraviolet cutting property (see, for example, Patent Document 1).

Recently, a silicone-based inorganic coating film 4 containing a photocatalyst has been formed on the clear inorganic coating film 3. The photocatalyst is activated by the irradiation of ultraviolet rays and can decompose dirt adhering to the surface. Moreover, in order to make the surface hydrophilic, the decomposed dirt can be washed away with rain water, etc., and a self-cleaning effect is obtained. (See, for example, Patent Document 2).
Japanese Patent No. 2574061 Japanese Patent No. 2776259

  In the coated body in which the organic coating film 2, the inorganic coating film 3, and the photocatalyst-containing inorganic coating film 4 are formed on the surface of the ceramic base material 1 as described above, the photocatalyst-containing inorganic coating film 4 contains a photocatalyst. Have problems with adhesion. Therefore, when the photocatalyst-containing inorganic coating film 4 is formed by applying the photocatalyst-containing coating agent on the surface of the inorganic coating film 3, sufficient adhesion between the inorganic coating film 3 and the photocatalyst-containing inorganic coating film 4 is obtained. However, there was a problem that sometimes it was not possible.

  This invention is made | formed in view of said point, can improve the durability by improving the adhesiveness of an inorganic coating film and a photocatalyst containing inorganic coating film, and can also improve antifouling property. The object is to provide a painted body.

  The coated body according to claim 1 of the present invention is a coated body in which a coating film is formed in the order of an organic coating film, an inorganic coating film, and a photocatalyst-containing inorganic coating film on the surface of a ceramic base material. The surface roughness Ra is 0.2 to 3 μm.

  The invention of claim 2 is characterized in that, in claim 1, the inorganic coating film and the photocatalyst-containing inorganic coating film are formed by painting with a silicone coating agent.

  The invention of claim 3 is characterized in that, in claim 1 or 2, the organic coating film is formed by painting an organic coating agent mainly comprising at least one of an acrylic emulsion and an acrylic silicone emulsion. is there.

  The invention of claim 4 is characterized in that, in claim 2 or 3, the inorganic coating film is formed by applying a silicone-based coating agent and baking with a baking energy of 5000 ° C. · sec or more. It is.

  According to the present invention, the inorganic coating film and the photocatalyst are set by setting the surface roughness Ra of the inorganic coating film, that is, the surface roughness Ra at the interface between the inorganic coating film and the photocatalyst-containing inorganic coating film to 0.2 to 3 μm. The contact area with the contained inorganic coating film can be increased, and the adhesion between the inorganic coating film and the photocatalyst-containing inorganic coating film can be increased to improve the durability of the coating film. Moreover, the surface roughness of the photocatalyst-containing inorganic coating film can be formed on the surface of the inorganic film with the surface roughness of the inorganic coating film, and the surface area of the photocatalyst-containing inorganic coating film can be increased to obtain a high photocatalytic effect on the surface. It is a thing and can improve antifouling property.

  Hereinafter, the best mode for carrying out the present invention will be described.

  As the ceramic base material, any material such as a cement exterior material can be used.For example, an inorganic filler, a fibrous material, etc. are blended into a hydraulic glue used as a raw material for an inorganic cured body, It is produced by curing after molding. The hydraulic glue is not particularly limited, and for example, one or more kinds selected from Portland cement, blast furnace cement, blast furnace slag, calcium silicate, gypsum and the like can be used. Also, fly ash, micro silica, silica sand, etc. are used as the inorganic filler, and inorganic fibers such as pulp, synthetic fiber, asbestos, etc., and metal fibers such as steel fibers, etc., are used alone or in combination as a fibrous material. be able to. Molding can be performed by methods such as extrusion molding, cast molding, papermaking molding, press molding, etc. After molding, ceramics used as an exterior material by performing autoclave curing, steam curing, room temperature curing as necessary A system substrate can be produced.

  And the coating body like FIG. 1 can be obtained by forming the organic coating film 2, the inorganic coating film 3, and the photocatalyst containing inorganic coating film 4 on the surface of this ceramic base material 1. FIG. By coloring the organic coating film 2 and forming the inorganic coating film 3 and the photocatalyst-containing inorganic coating film 4 transparently, the organic coating film 2 is made up of a coated body, and the organic coating film 2 is deteriorated by ultraviolet rays. While preventing with the inorganic coating film 3, antifouling property can be provided with the photocatalyst contained in the photocatalyst containing inorganic coating film 4 of the outermost layer.

  In the present invention, the organic coating agent for forming the organic coating film 2 is not particularly limited, but it is preferable to use an organic coating agent mainly composed of an acrylic emulsion or an acrylic silicone emulsion. By forming the organic coating film 2 with an acrylic emulsion or an acrylic silicone emulsion in this way, high adhesion between the organic coating film 2 and the inorganic coating film 3 formed thereon can be obtained. .

  As the acrylic emulsion, for example, a core-shell type acrylic emulsion disclosed in JP-A No. 2004-195934 can be used. That is, the core-shell type acrylic emulsion is a copolymer emulsion obtained by copolymerizing a monomer component mainly composed of acrylamide in the presence of a seed emulsion as a core particle.

  Seed emulsions such as acrylic ester, styrene / acrylate ester, acrylonitrile, styrene-butadiene, acrylonitrile-butadiene, acrylate-butadiene, vinyl chloride, vinyl acetate, etc. Molecular emulsions can be used, and they can be used alone or in combination of two or more.

  Moreover, in said monomer component, the unsaturated monomer copolymerizable with acrylamide is contained as needed. As this unsaturated monomer, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-aminoethyl acrylate, acrylic acid 2- (N-methylamino) ethyl, 2- (N, N-dimethylamino) ethyl acrylate, acrylic esters such as glycidyl acrylate, vinyl esters such as vinyl acetate and vinyl propionate, and nitriles such as acrylonitrile Group-containing monomers, unsaturated carboxylic acids such as acrylic acid, maleic anhydride, fumaric acid, itaconic acid, crotonic acid, aromatic vinyl monomers such as styrene, α-methylstyrene, divinylbenzene, N- N-substituted unsaturated carboxylic acid amides such as methylolacrylamide can be selected. That. Among these, it is preferable to use an unsaturated monomer having a functional group such as a carboxyl group, a hydroxyl group, an amino group, a methylol group, or a glycidyl group.

  This core-shell structure acrylic emulsion is produced by a known polymerization technique using a polymerization initiator and a chain transfer agent together with the above-mentioned materials. Such core-shell type acrylic emulsions have various types known so far (see, for example, JP-A-2000-204285), and commercially available products can also be used.

  Among such core-shell type acrylic emulsions, it is preferable to use those having an acid amount in the range of 5 to 15% by weight in the shell portion. By setting the acid amount of the shell part in this range, the interlayer adhesion strength between the organic coating film and the inorganic coating film can be increased. When the acid amount of the shell part is less than 5% by weight, The improvement of the interlayer adhesion strength with the inorganic coating film cannot be expected. The same applies when the acid amount of the shell part exceeds 15% by weight.

  Moreover, as an acrylic silicone emulsion, what mix | blended the silicone component with the acrylic emulsion currently disclosed by patent 3347097 can be used, for example.

The acrylic emulsion preferably contains methyl methacrylate and butyl acrylate as resin main components. The organic coating film must satisfy one of the following requirements.
(1) The gel fraction of the organic coating film with respect to the organic solvent is 30% or less.
(2) The Tg (glass transition temperature) of the organic coating film is 50 ° C. or lower.
(3) The contact angle of the top coat inorganic coating film with the inorganic coating agent is 40 degrees or less.

  In the case of a coated body in which the organic coating film as described above is formed and the surface thereof is coated with an inorganic coating agent, the coating film adhesion due to the inorganic coating agent is extremely excellent as well as weather resistance. Making the gel fraction of the organic coating film low with respect to the organic solvent as in (1) means that the organic coating film is easily exposed to the organic solvent. Here, the gel fraction is an index of solvent resistance. Specifically, for example, the gel fraction of the organic coating film is obtained by immersing the organic coating film dried (120 ° C., 4 minutes) after application in acetone for 5 hours. It is shown as a weight ratio remaining after the treatment.

  The organic coating and inorganic coating have a low gel fraction, that is, low solvent resistance, because the organic solvent in the top coating of the inorganic coating agent swells the organic coating at the interface with the organic coating. This means that the organic coating film and the inorganic coating film are melted and a strong physical adhesion is obtained, and the situation is strong against changes over time. The gel fraction of the organic coating is preferably 30% or less, more preferably 0%, or a value close thereto, so that the organic coating is strong with the inorganic coating by the inorganic coating agent. Adhesion can be obtained.

  The gel fraction with respect to the organic solvent can be lowered by selecting the resin component in the organic coating agent and adjusting the composition and the ratio thereof. For example, in an acrylic emulsion prepared with molecular weights of approximately the same level, methyl methacrylate (MMA) and butyl acrylate (BA) are included in the resin main component, that is, 50% by weight or more of the resin component. The ratio of the components and the mutual ratio of methyl methacrylate (MMA) and butyl acrylate (BA) are adjusted. In order to lower the gel fraction, it is generally appropriate that the ratio of methyl methacrylate (MMA) and butyl acrylate (BA) as main components is MMA / BA = 1 to 2 as a weight ratio. More preferably, MMA / BA = 1.1 to 1.6. When the ratio of methyl methacrylate (MMA) exceeds 2, the gel fraction cannot be expected to be reduced to 30% or less, and a substantial improvement in adhesion cannot be obtained. On the other hand, when the weight ratio is less than 1, the strength, durability, etc. of the coating film as a coated body tend not to be sufficient. Further, in the range of the weight ratio MMA / BA = 1.1 to 1.6, the gel fraction is substantially 0, and excellent adhesion can be obtained. It should be noted that the proportion of methyl methacrylate (MMA) and butyl acrylate (BA) as the main component of the resin is preferably 60% by weight or more, and blending of acrylate or methacrylate as the other component is appropriate. Is possible.

  Further, as shown in (2), when the Tg is set to a low level of 50 ° C. or lower, the organic coating film is softened and the interface with the inorganic coating film tends to be in a fused state, resulting in a physically strong result. A coated product having adhesiveness can be obtained.

  Further, as in (3), the adhesiveness between the organic coating film and the inorganic coating film can also be improved by reducing the contact angle of the inorganic coating agent for overcoating to the organic coating film to 40 degrees or less. . The small contact angle with respect to the inorganic coating agent means that the wettability is good, that is, the inorganic coating agent can be uniformly applied to the organic coating film, and it is generated by drainage of the organic coating film, etc. It means that the inorganic coating agent penetrates into the pores (pores) and the like, an anchoring effect is obtained and stabilized, and the adhesion is improved.

  Thus, in order to make a contact angle small, a silicone component is mix | blended with an acrylic emulsion, and it uses as an acrylic silicone emulsion. When blending the silicone component into the acrylic emulsion, the proportion of the total resin component is suitably in the range of 5 wt% to 20 wt%. If the amount is less than 5% by weight, no substantial effect is obtained. On the other hand, if the amount exceeds 20% by weight, the performance deteriorates in terms of water resistance.

  An organic coating agent can be obtained by mix | blending various components with the acrylic emulsion and acrylic silicone emulsion obtained as mentioned above as needed.

  For example, an emulsifier and a dispersant can be appropriately blended in the emulsion. Low molecular emulsifiers and reactive emulsifiers can be preferably used. However, from the viewpoint of coating film adhesion, it is desirable to suppress the use of low molecular emulsifiers that cause poor adhesion as a free soap, so the proportion of low molecular emulsifier is less than 50% and reactive emulsifier is 50% or more. Is desirable. In addition, pigments, fillers, mineral oil-based antifoaming agents, thickeners, paraffin-based water repellents, and the like can be appropriately blended in the emulsion. Examples of pigments include organic pigments such as carbon black, quinacridone, naphthol red, cyanine blue, cyaning ray, and hansa yellow, and inorganic pigments such as titanium oxide, barium sulfate, bengara, calcium carbonate, alumina, iron oxide, and composite metal oxides. Examples of fillers include general silica powder, barium sulfate, sand, and resin beads. The particle size of the pigment or filler is not particularly limited. The blending of components other than the resin component is preferably 5% by weight or less with respect to the entire emulsion.

  Next, in the present invention, the inorganic coating agent for forming the inorganic coating film 3 is not particularly limited, but a silicone coating agent is preferably used. As this silicone type coating agent, what is disclosed by patent 3243442, patent 3193382, and Unexamined-Japanese-Patent No. 9-249822 can be used, for example.

The silicone-based coating agent disclosed in Japanese Patent No. 3243442 is
(A): General formula R ¹ _n SiX _4-n (1)
(In the formula (1), R ¹ is the same or different alkyl group, cycloalkyl group, alkenyl group, halogen-substituted hydrocarbon group, γ-methacryloxypropyl group, γ-glycidoxypropyl group, 3,4- A monovalent hydrocarbon group having 1 to 8 carbon atoms selected from the group consisting of an epoxycyclohexylethyl group and a γ-mercaptopropyl group, n is an integer of 0 to 3, X is an alkoxy group, an acetoxy group, an oxime group, A hydrolyzable group selected from the group consisting of an enoxy group, an amino group, an aminoxy group and an amide group.
An organosilane obtained by partially hydrolyzing a hydrolyzable organosilane represented by the formula (I) in colloidal silica dispersed in an organic solvent or water under the condition that 0.001 to 0.5 mol of water is used per 1 mol of X. Silica dispersion oligomer solution of
(B): the average compositional formula _{^{R 2 a Si (OH) b}} O (4-a-b) / 2 (2)
(In the formula (2), R ² is the same or different alkyl group, cycloalkyl group, alkenyl group, halogen-substituted hydrocarbon group, γ-methacryloxypropyl group, γ-glycidoxypropyl group, 3,4- A monovalent hydrocarbon group having 1 to 8 carbon atoms selected from the group consisting of an epoxycyclohexylethyl group and a γ-mercaptopropyl group, wherein a and b are 0.2 ≦ a ≦ 2, 0.0001 ≦ b ≦, respectively. 3 and a number satisfying the relationship of a + b <4.)
And a polyorganosiloxane containing 1 to 30 mol% of phenyl groups based on the total R ² groups in R ² of the component, and
(C): A catalyst that accelerates the condensation reaction between the component (A) and the component (B) is an essential component, and the component (A) contains 5 to 95% by weight of silica as a solid content. At least 50 mol% is an organosilane having n = 1, and 99 to 1 part by weight of component (B) is blended with 1 to 99 parts by weight of component (A).

  The silica-dispersed oligomer as the component (A) is a main component of a base polymer having a hydrolyzable group as a functional group to be subjected to a curing reaction during film formation. This was done by adding one or more hydrolyzable group-containing organosilanes represented by the general formula (1) to colloidal silica dispersed in an organic solvent or water, and adding water in colloidal silica or separately. It is obtained by partially hydrolyzing the hydrolyzable organosilane with water.

The group R ¹ in the hydrolyzable organosilane represented by the general formula (1) is an alkyl group, a cycloalkyl group, an alkenyl group, a halogen-substituted hydrocarbon group, a γ-methacryloxypropyl group, or a γ-glycidoxypropyl. A monovalent hydrocarbon group having 1 to 8 carbon atoms selected from the group consisting of a group, 3,4-epoxycyclohexylethyl group and γ-mercaptopropyl group, for example, methyl group, ethyl group, propyl group, butyl group Alkyl groups such as pentyl group, hexyl group, heptyl group and octyl group; cycloalkyl groups such as cyclopentyl group and cyclohexyl group; aralkyl groups such as 2-phenylethyl group and 3-phenylpropyl group; phenyl group and tolyl group Aryl groups such as vinyl groups, alkenyl groups such as allyl groups, chloromethyl groups, γ-chloropropyl groups, , 3,3-trifluoropropyl groups such as halogen-substituted hydrocarbon groups and γ-methacryloxypropyl groups, γ-glycidoxypropyl groups, 3,4-epoxycyclohexylethyl groups, γ-mercaptopropyl groups, etc. A hydrocarbon group etc. can be illustrated. Among these, an alkyl group having 1 to 4 carbon atoms and a phenyl group are preferable because of easy synthesis or availability.

  X of the hydrolyzable group is a hydrolyzable group selected from the group consisting of an alkoxy group, an acetoxy group, an oxime group, an enoxy group, an amino group, an aminoxy group, and an amide group. Alkoxy groups are preferred because of their availability and ease of preparing silica-dispersed oligomer solutions.

  Particularly, tetramethoxysilane, tetraethoxysilane and the like can be exemplified as tetraalkoxysilane of n = 0, and methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, n = 1 as organotrialkoxysilane, Examples thereof include phenyltrimethoxysilane, phenyltriethoxysilane, and 3,3,3-trifluoropropyltrimethoxysilane. Examples of n = 2 diorganodialkoxysilanes include dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, and methylphenyldimethoxysilane, and n = 3 triorganoalkoxysilane. Examples thereof include trimethylmethoxysilane, trimethylethoxysilane, trimethylisopropoxysilane, and dimethylisobutylmethoxysilane. Furthermore, organosilane compounds generally called silane coupling agents are also included in the alkoxysilanes.

  Of these hydrolyzable organosilanes represented by the general formula (1), 50 mol% or more is required to be a trifunctional one represented by n = 1. They are more preferably 60 mol% or more, most preferably 70 mol% or more. If this is less than 50 mol%, sufficient coating film hardness cannot be obtained, and the dry curability tends to be poor.

  The colloidal silica in the component (A) is essential for increasing the hardness of the cured film of the silicone-based coating agent. As such colloidal silica, water-dispersible or non-aqueous organic solvent-dispersible colloidal silica such as alcohol can be used. Generally, such colloidal silica contains 20 to 50% by weight of silica as a solid content, and the amount of silica can be determined from this value. Moreover, when using water dispersible colloidal silica, the water which exists as components other than solid content can be used for a hydrolysis of the organosilicon compound of (A) component. These are usually made from water glass, but such colloidal silica is readily available commercially. The organic solvent-dispersed colloidal silica can be easily prepared by replacing the water of the water-dispersible colloidal silica with an organic solvent. Such an organic solvent-dispersed colloidal silica can also be easily obtained as a commercial product, like the water-dispersed colloidal silica. Examples of the organic solvent in which colloidal silica is dispersed include, for example, lower aliphatic alcohols such as methanol, ethanol, isopropanol, n-butanol, and isobutanol; ethylene glycol, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether acetate, and the like. And ethylene glycol derivatives; derivatives of diethylene glycol such as diethylene glycol and diethylene glycol monobutyl ether, diacetone alcohol, and the like, and one or more selected from the group consisting of these can be used. In combination with these hydrophilic organic solvents, toluene, xylene, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, methyl ethyl ketoxime, and the like can also be used.

  In the component (A), colloidal silica is contained in the range of 5 to 95% by weight as the silica content. More preferably, it is 10 to 90 weight%, Most preferably, it is the range of 20 to 85 weight%. If the content is less than 5% by weight, the desired film hardness cannot be obtained, and if it exceeds 95% by weight, it is difficult to uniformly disperse silica, and component (A) may cause problems such as gelation. .

  The silica-dispersed oligomer of component (A) can be usually obtained by partially hydrolyzing a hydrolyzable group-containing organosilane in water-dispersed colloidal silica or organic solvent-dispersed colloidal silica. The amount of water used relative to the hydrolyzable organosilane is preferably 0.001 to 0.5 mol of water with respect to 1 mol of the hydrolyzable group (X). When the ratio is less than 0.001 mol, a sufficient partial hydrolyzate cannot be obtained, and when it exceeds 0.5 mol, the stability of the partial hydrolyzate is deteriorated. The method of partial hydrolysis is not particularly limited, and a hydrolyzable organoalkoxysilane and colloidal silica may be mixed and added with a necessary amount of water, and at this time, the partial hydrolysis reaction proceeds at room temperature. You may heat to 60-100 degreeC in order to accelerate a partial hydrolysis reaction. Furthermore, hydrochloric acid, acetic acid, halogenated silane, chloroacetic acid, citric acid, benzoic acid, dimethylmalonic acid, formic acid, propionic acid, glutaric acid, glycolic acid, maleic acid, malonic acid, toluene for the purpose of promoting partial hydrolysis reaction Organic acids such as sulfonic acid and oxalic acid and inorganic acids may be used as the catalyst.

  In order to obtain the component (A) stably in the long term, the pH of the liquid is 2.0 to 7.0, preferably 2.5 to 6.5, more preferably 3.0 to 6.0. It is good to do. If the pH is outside this range, the amount of water used is 0.3 mol or more per 1 mol of the group (X), and the long-term performance deterioration of the component (A) is remarkable. When the pH of the component (A) is outside this range, it may be adjusted by adding a basic reagent such as ammonia or ethylenediamine if it is more acidic than this range. Adjustment may be performed using an acidic reagent such as acetic acid. However, the adjustment method is not particularly limited.

The silanol group-containing polyorganosiloxane (B) represented by the average composition formula (2) is an important component that characterizes the present invention. (2) In the formula, as R ² , the same as R ¹ in the formula (1) is exemplified, but preferably an alkyl group having 1 to 4 carbon atoms, a vinyl group, a γ-glycidoxypropyl group, Substituted hydrocarbon groups such as γ-methacryloxypropyl group and 3,3,3-trifluoropropyl group, more preferably methyl group. Further, in the formula, a and b are numbers satisfying the above relationship, respectively, and if a is less than 0.2 or b exceeds 3, there is a problem such as a crack in the cured film, and a exceeds 2 When it is 4 or less or when b is less than 0.0001, curing does not proceed well.

Further, ^{R 2} is 1 to 30 mol% of the total ^{R 2} groups phenyl group, preferably it to contain 5 to 20 mol%, the resulting coating film having excellent gloss, leveling. If the number of phenyl groups is less than 1 mol% based on the total R ² groups, the desired gloss cannot be obtained, and if it exceeds 30 mol%, the gloss decreases and the coating film becomes soft.

  Such a silanol group-containing polyorganosiloxane can be prepared by a known method using a large amount of methyltrichlorosilane, dimethyldichlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, or a mixture of one or more of the corresponding alkoxysilanes. It can be obtained by hydrolysis with water. When a silanol group-containing polyorganosiloxane is obtained by hydrolysis with a known method using alkoxysilane, a trace amount of alkoxy groups that are not hydrolyzed may remain. That is, a polyorganosiloxane in which a silanol group and a trace amount of an alkoxy group coexist may be obtained, but such a polyorganosiloxane may be used.

  The curing catalyst which is the component (C) accelerates the condensation reaction between the component (A) and the component (B) and cures the coating. Examples of such catalysts include metal salts of carboxylic acids such as alkyl titanates, tin octylate and dibutyltin dilaurate, dioctyltin dimaleate; amine salts such as dibutylamine-2-hexoate, dimethylamine acetate, and ethanolamine acetate; Quaternary ammonium salts of carboxylic acids such as tetramethylammonium acetate; amines such as tetraethylpentamine; N-β-aminoethyl-γ-aminopropyltrimethoxysilane, N-β-aminoethyl-γ-aminopropylmethyl Amine-based silane coupling agents such as dimethoxysilane; acids such as p-toluenesulfonic acid, phthalic acid and hydrochloric acid; aluminum compounds such as aluminum alkoxide and aluminum chelate; alkali catalysts such as potassium hydroxide; tetraisopropyl titane , Tetrabutyl titanate, titanium tetraacetylacetonate and other titanium compounds, methyltrichlorosilane, dimethyldichlorosilane, trimethylmonochlorosilane, and other halogenated silanes. In addition to these, component (A) and component (B) There is no particular limitation as long as it is effective for the condensation reaction with.

  The blending ratio of the component (A) and the component (B) is 99 to 1 part by weight of the component (B) with respect to 1 to 99 parts by weight of the component (A), more preferably 5 to 95 parts by weight of the component (A). The component (B) is 95 to 5 parts by weight, and most preferably the component (B) is 90 to 10 parts by weight with respect to the component (A) 10 to 90 parts by weight (provided that the component (A) and the component (B) The total of the components is 100 parts by weight). When the component (A) is less than 1 part by weight, the room temperature curability is inferior and sufficient film hardness cannot be obtained. On the other hand, when it exceeds 99 parts by weight, the curability is unstable and a good coating film is obtained. There may not be.

  Moreover, it is preferable that the addition amount of (C) component is 0.0001-10 weight part with respect to 100 weight part in total of (A) component and (B) component. More preferably, it is 0.0005-8 weight part, Most preferably, it is 0.0007-5 weight part. If it is less than 0.0001 part by weight, it will not be cured at room temperature. Moreover, when it exceeds 10 weight part, heat resistance and a weather resistance will worsen.

  This silicone-based coating agent can be used by diluting with various organic solvents for ease of handling. The type of the organic solvent can be selected according to the type of the monovalent hydrocarbon group or the molecular weight of the component (A) or the component (B). Examples of such organic solvents include lower aliphatic alcohols such as methanol, ethanol, isopropanol, n-butanol, and isobutanol shown as dispersion solvents for colloidal silica; ethylene glycol, ethylene glycol monobutyl ether, and ethylene glycol monoethyl acetate. Examples include ethylene glycol derivatives such as ether; derivatives of diethylene glycol such as diethylene glycol and diethylene glycol monobutyl ether, and diacetone alcohol. One or two or more selected from the group consisting of these can be used. . Examples of solvents that can be used in combination with these hydrophilic organic solvents include toluene, xylene, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, and methyl ethyl ketoxime.

  As a method for storing this silicone-based coating agent, it is common to take a three-packed form in which the components (A), (B), and (C) are stored, but the components (A) and (C) It is also possible to separate the mixed component and the component (B) into two package types and mix them at the time of use, or mix all the components and store them in one container. However, when mixing and storing (A) component and (C) component, it is preferable to add (C) component after adjusting the pH of (A) component to 2-7, and also (A) component The amount of water used per 1 mol of the hydrolyzable group (X) of the organoalkoxysilane is preferably 0.3 mol or less.

  In addition, this silicone-based coating agent has properties such as leveling agents, thickeners, pigments, dyes, aluminum paste, glass frit, metal powder, antioxidants, matting agents, and UV absorbers as necessary. It can be added within a range that does not affect.

Next, the silicone-based coating agent disclosed in Japanese Patent No. 3193932 is
General formula R ¹ _n SiX _4-n (3)
(In formula (3), R ¹ represents the same or different substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms, n represents an integer of 0 to 3, and X represents a hydrolyzable group)
In a state where 0.001 to 0.5 mol of water is used per 1 mol of X1 in a state where fine particle oxide is dispersed in a particle size of 0.2 to 3 μm, the hydrolyzable organosilane represented by To what was obtained by hydrolysis,
General formula OH (R ² ₂ SiO) _m H (4)
(In formula (4), R ² represents the same or different substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms, and m represents 1 or more.)
A silicone diol-containing fine particle oxide-dispersed oligomer (component D) containing 5 to 30% by weight of a silicone diol component having a weight average molecular weight of 10,000 or less represented by:
Average composition formula R ³ _a Si (OH) _b O _{(4-ab) / 2} (5)
(In the formula (5), R ³ represents the same or different substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms, and a and b are 0.2 ≦ a <2.0, 0,. (A number satisfying the relationship of 0001 ≦ b ≦ 3 and a + b <4)
A polyorganosiloxane (E component) containing a silanol group in the molecule represented by:
Each component of the catalyst (F component) is contained.

  The silicone diol-containing fine particle oxide-dispersed oligomer of component D is the main component of a base polymer having a hydrolyzable group X as a functional group that is subjected to a curing reaction during film formation. This is obtained by adding a silicone diol represented by the above general formula (4) to one or more hydrolyzable organosilanes represented by the above general formula (3). It can be obtained by partially hydrolyzing the hydrolyzable organosiloxane by adding a necessary amount of water while dispersing the fine particle oxide or after completing the fine particle oxide dispersion. The silicone diol may be added before hydrolyzing the hydrolyzable organosilane, at the time of hydrolysis, or after hydrolysis.

Here, the group R ¹ in the hydrolyzable organosilane represented by the general formula (3) represents a substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms, such as a methyl group or an ethyl group. Group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group and other alkyl groups; cyclopentyl group, cyclohexyl group and other cycloalkyl groups; 2-phenylethyl group, 2-phenylpropyl group, 3-phenylpropylene Aralkyl groups such as ruthel groups; aryl groups such as phenyl groups and tolyl groups; alkenyl groups such as vinyl groups and allyl groups; halogen substitutions such as chloromethyl groups, γ-chloropropyl groups, and 3,3,3-trifluoropropyl Hydrocarbon group; and γ-methacryloxypropyl group, γ-glycidoxypropyl group, 3,4-epoxycyclohexylethyl group, γ-medium It may be exemplified substituted hydrocarbon group such as mercaptopropyl group. Among these, an alkyl group having 1 to 4 carbon atoms and a phenyl group are preferable because of easy synthesis or availability.

  Examples of the hydrolyzable group X in the hydrolyzable organosilane represented by the general formula (3) include an alkoxy group, an acetoxy group, an oxime group, an enoxy group, an amino group, an aminoxy group, and an amide group. . Alkoxy groups are preferred because of their availability and ease of preparing fine particle oxide-dispersed oligomer solutions.

  Such hydrolyzable organosilanes include mono-, di-, tri-, and tetra-functional alkoxysilanes in which n in the general formula (3) is an integer of 0 to 3, Examples include acetoxysilanes, oxime silanes, enoxysilanes, aminosilanes, aminoxysilanes, and amidosilanes. Alkoxysilanes are preferred because they are readily available and easy to prepare a fine particle oxide-dispersed oligomer solution.

  In particular, tetramethoxysilane, tetraethoxysilane, and the like can be exemplified as the n = 0 tetraalkoxysilane, and the methyltrialkoxysilane, methyltriethoxysilane, methyltrimethoxysilane, and the like can be exemplified as the n = 1 organotrialkoxysilane. Examples thereof include isopropoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane and the like. Examples of n = 2 diorganodialkoxysilanes include dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, and methylphenyldimethoxysilane, and n = 3 triorganoalkoxysilane. Examples of silane include trimethylmethoxysilane, trimethylethoxysilane, trimethylisopropoxysilane, and dimethylisobutylmethoxysilane. An organosilane compound generally called a silane coupling agent can also be used as alkoxysilanes.

  Of the hydrolyzable organosilanes represented by the general formula (3) as described above, 50 mol% or more is preferably trifunctional with n = 1. More preferably, it is 60 mol% or more, and most preferably 70 mol% or more. When the trifunctional compound of n = 1 is less than 50 mol%, it is difficult to obtain a sufficient film hardness and the dry curability may be easily deteriorated.

  The fine particulate oxide in the component D is essential for controlling the gloss of the coating composition and acts as a matting agent. Examples of the fine particle oxide include silicon oxide, aluminum oxide, titanium oxide, etc., and those whose surfaces are subjected to silica treatment, alumina treatment, coupling treatment, etc. for the purpose of enhancing dispersibility. Can be used.

  Then, the particulate oxide is directly dispersed in the hydrolyzable organosilane represented by the general formula (3), and the hydrolyzable organosilane is partially hydrolyzed with a necessary amount of water to prepare the component D. However, for the purpose of increasing the degree of dispersion of the powdered fine particle oxide, it is dispersed with an organic solvent such as alcohol, and the hydrolyzable organosilane is partially hydrolyzed with a necessary amount of water to prepare the component D. Also good. Examples of the organic solvent include lower aliphatic alcohols such as methanol, ethanol, isopropanol, n-butanol and isobutanol; ethylene glycol derivatives such as ethylene glycol, ethylene glycol monobutyl ether and ethylene glycol monoethyl ether; diethylene glycol, And diethylene glycol derivatives such as diethylene glycol monobutyl ether; and diacetone alcohol. One or two or more selected from the group consisting of these can be used, but in combination with these hydrophilic organic solvents, toluene, xylene, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, Methyl ethyl ketoxime can also be used.

  The particle diameter of the fine particle oxide dispersed in the hydrolyzable organosilane oligomer of component D is in the range of 0.2 to 3 μm. When the particle diameter is less than 0.2 μm, it is difficult to control the gloss, and when the particle diameter exceeds 3 μm, the film formability may be impaired. In the component D, the fine particle oxide is contained in the range of preferably 5 to 30% by weight, more preferably 8 to 25% by weight as the solid content. When the content is less than 5% by weight, it is difficult to control the gloss, and when it exceeds 30% by weight, there is a possibility that inconveniences such as impaired film formability may be caused.

The silicone diol in component D is essential for obtaining a stable gloss of the coating composition. The compounding ratio in the D component of the silicone diol represented by the general formula (4) is 5 to 30% by weight. If it is less than 5% by weight, it is difficult to obtain long-term gloss stability, and if it exceeds 30% by weight, curing of the coating film may be delayed. The weight average molecular weight of the silicone diol component is 10,000 or less, preferably 5000 or less, more preferably 1000 or less. A silicone diol component having a weight average molecular weight exceeding 10,000 has poor compatibility with the resin and is difficult to use. Here, R ^{2 in} the general formula (4) of the silicone diol can be used without particular limitation as long as it is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms. The hydrocarbon group similar to R < ¹ > in the said Formula (3) can be mentioned.

  The organosilane oligomer of component D can be obtained by partially hydrolyzing the hydrolyzable organosilane of the general formula (1). The amount of water used relative to the hydrolyzable organosilane is 0.001 to 0.5 mol of water relative to 1 mol of the hydrolyzable group X. When the amount of water used is less than 0.001 mol, a sufficient partial hydrolyzate cannot be obtained, and when the amount of water used exceeds 0.5 mol, the stability of the partial hydrolyzate becomes poor. The method of partial hydrolysis is not particularly limited, and a hydrolyzable organosilane and a necessary amount of water may be added and blended. At this time, the partial hydrolysis reaction proceeds at room temperature, but the partial hydrolysis reaction is promoted. Therefore, heating may be performed at a temperature of 60 to 100 ° C. Furthermore, hydrochloric acid, acetic acid, halogenated silane, chloroacetic acid, citric acid, benzoic acid, dimethylmalonic acid, formic acid, propionic acid, glutaric acid, glycolic acid, maleic acid, malonic acid, toluene for the purpose of promoting partial hydrolysis reaction An inorganic acid such as sulfonic acid or oxalic acid or an organic acid may be used as a catalyst.

  In order to obtain long-term stable performance, the silicone diol-containing fine particle oxide-dispersed oligomer of component D has a pH of the liquid in the range of 2.0 to 7.0, more preferably pH 2.5 to 6.5. It is better to adjust to the range, even more preferably to the range of pH 3.0 to 6.0. When the pH is out of this range, the long-term performance deterioration of the D component may be remarkable particularly when the amount of water used is 0.3 mol or more with respect to X1 mol. If the pH of component D is outside this range, a basic reagent such as ammonia or ethylenediamine may be added to adjust the pH when it is acidic from this range, and hydrochloric acid, nitric acid, What is necessary is just to adjust pH using acidic reagents, such as an acetic acid. The adjustment method is not particularly limited.

The silanol group-containing polyorganosiloxane of E component whose average composition formula is represented by the above formula (5) is an important component constituting one of the characteristics of the silicone coating agent. In formula (5), R ³ may be the same as R ¹ in formula (3), preferably an alkyl group having 1 to 4 carbon atoms, a phenyl group, a vinyl group, γ- Substituted hydrocarbon groups such as a glycidoxypropyl group, γ-methacryloxypropyl group, and 3,3,3-trifluoropropyl group, more preferably a methyl group and a phenyl group. In the formula (5), a and b are numbers satisfying the relations 0.2 ≦ a <2.0, 0.0001 ≦ b ≦ 3, and a + b <4, respectively, and a is less than 0.2 or b is If it exceeds 3, there are disadvantages such as causing cracks in the cured film, and if a is more than 2.0 and 4 or less, or if b is less than 0.0001, there is an inconvenience that curing does not proceed well.

  Examples of such a silanol group-containing polyorganosiloxane of formula (5) include, for example, methyltrichlorosilane, dimethyldichlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, or one or a mixture of two or more alkoxysilanes corresponding thereto. Can be obtained by hydrolysis with a large amount of water by a known method. When a silanol group-containing polyorganosiloxane is obtained by hydrolysis using a known method using alkoxysilane, a trace amount of alkoxy groups that are not hydrolyzed may remain. That is, a polyorganosiloxane in which a silanol group and a trace amount of an alkoxy group coexist may be obtained, but such a polyorganosiloxane may be used.

  The F component catalyst serves as a curing catalyst for accelerating the condensation reaction between the D component and the E component and curing the coating. Examples of such catalysts include metal salts of carboxylic acids such as alkyl titanates, tin octylate and dibutyltin dilaurate, dioctyltin dimaleate; amine salts such as dibutylamine-2-hexoate, dimethylamine acetate, and ethanolamine acetate; Quaternary ammonium salts such as tetramethylammonium acetate, amines such as tetraethylpentamine; N (-β-aminoethyl) -γ-aminopropyltrimethoxysilane, N (-β-aminoethyl) -γ -Amine-based silane coupling agents such as aminopropylmethyldimethoxysilane; acids such as p-toluenesulfonic acid, phthalic acid and hydrochloric acid; aluminum compounds such as aluminum alkoxide and aluminum chelate; alkali catalysts such as potassium hydroxide; tetraisopropyl tita And titanium compounds such as tetrabutyltitanate and titanium tetraacetylacetonate, and halogenated silanes such as methyltrichlorosilane, dimethyldichlorosilane, and trimethylmonochlorosilane. There is no particular limitation as long as it is effective for the condensation reaction.

  The mixing ratio of the D component and the E component is preferably 70 to 30 parts by weight of the E component with respect to 30 to 70 parts by weight of the D component, more preferably 60 to 40 parts by weight of the E component with respect to 40 to 60 parts by weight of the D component. (However, the total amount of D component and E component is 100 parts by weight). When the D component is less than 30 parts by weight, it is difficult to control the gloss of the resulting inorganic coating film, and when the E component exceeds 70 parts by weight, the film formability of the inorganic coating film may be impaired. By changing the blending ratio of the D component and the E component in the above range, the gloss of the inorganic coating film can be easily adjusted. When the blending ratio is adjusted so as to increase the D component, the inorganic coating film The glossiness of the inorganic coating film can be increased by adjusting the blending ratio so as to reduce the D component.

  Moreover, it is preferable that the addition amount of the catalyst of F component is 0.0001-10 weight part with respect to a total of 100 weight part of D component and E component. More preferably, it is 0.0005-8 weight part, Most preferably, it is 0.0007-5 weight part. If the addition amount of the F component catalyst is less than 0.0001 parts by weight, it may not be cured at room temperature, and if the addition amount of the F component catalyst exceeds 10 parts by weight, the heat resistance and weather resistance of the resulting inorganic coating film May be worse.

  The silicone-based coating agent prepared as described above can be used after being diluted with various organic solvents for ease of handling. The type of the organic solvent is selected according to the type or molecular weight of the D component or E component monovalent hydrocarbon group. Examples of such an organic solvent include those shown as dispersion solvents for fine particle oxides, etc. 1 type or 2 types or more selected from the group consisting of these can be used.

  This silicone coating agent is generally stored in a three-packed form in which the D component, the E component, and the F component are stored separately, but the mixed component of the D component and the F component, the E component, The two may be divided into two package types, and the two may be mixed at the time of use. Alternatively, all the components may be mixed and stored in one container. However, when the D component and the F component are mixed and stored, it is preferable to adjust the pH of the D component to 2 to 7 and then add and mix the F component. It is preferable to use a solution in which the amount of water used is 0.3 mol or less with respect to 1 mol of the hydrolyzable group.

  In addition, this silicone-based coating agent does not affect the properties of leveling agents, thickeners, pigments, dyes, aluminum paste, glass frit, metal powder, antioxidants, UV absorbers, etc. as necessary. It can be added within the range.

Next, JP-A-9-249822 discloses two types of silicone coating agents. One of the two types of silicone coating agents (hereinafter referred to as silicone coating agent (1))
General formula (R ¹ ) _m Si (OR ² ) _4-m (6)
(In the formula (6), ^{R 1} each represent a methyl group, an ethyl group or a phenyl group, ^{R 2} is .m each represents an alkyl group having 1 to 8 carbon atoms is 0, 1 or 2.)
An ultraviolet absorber is blended with a silicon alkoxide-based coating agent mainly composed of a silicon compound represented by formula (1) and / or a partial hydrolyzate thereof.

The silicon alkoxide mainly composed of the silicon compound represented by the general formula (6) and / or a partial hydrolyzate thereof is a mixture mainly composed of the following compounds (i), (ii) and (iii): Can be obtained by diluting with an appropriate solvent, adding a necessary amount of a curing agent and a catalyst, followed by hydrolysis and condensation polymerization, having a weight average molecular weight Mw of 500 to 3000 in terms of polystyrene, and a molecular weight distribution Mw / Mn ( Mn preferably has a number average molecular weight) of 1.1 to 3.0. More preferably, Mw = 600 to 3000 and Mw / Mn = 1.2 to 1.8. When the weight average molecular weight and the molecular weight distribution are smaller than these ranges, the curing shrinkage during the condensation polymerization becomes large, and cracks tend to occur in the coating film after baking. Also, when the weight average molecular weight and molecular weight distribution are larger than this range, the reaction is too slow and hard to cure, or even when cured, the coating tends to be soft, or the leveling properties of the coating tend to be very poor. There is.
(I): 20 to 200 parts by weight of the silicon compound and colloidal silica represented by m = 0 in the general formula (6) (ii): 100 parts by weight of the silicon compound represented by m = 1 in the general formula (6) (iii) ): 0 to 80 parts by weight of a silicon compound represented by m = 2 in the general formula (6) As these silicon compounds, alkoxysilanes in the later-described formula (7) can be used. Further, the component (i) colloidal silica (colloidal silica) is used by dispersing the fine particle silica component in water, an organic solvent such as methanol, or a mixed solvent thereof, as long as they are colloidal. There are no particular restrictions on the solvent type. In addition, the compounding quantity of the colloidal silica of a component (i) is a weight part also including a dispersion medium.

  Although it does not specifically limit as said hardening | curing agent used as needed in a silicone type coating agent (1), For example, inorganic acids, such as hydrochloric acid, phosphoric acid, a sulfuric acid, formic acid, an acetic acid, chloroacetic acid An acidic catalyst such as a dilute solution of an organic acid such as a basic catalyst described later can be used alone or in combination of two or more. Further, when colloidal silica is used as the component (i), the colloidal silica exhibits acidity, so that it becomes a catalyst, and nothing is required as an acidic catalyst.

  As the catalyst used as necessary in the silicone-based coating agent (1), a basic catalyst is used. The basic catalyst is not particularly limited. For example, amines such as triethanolamine; γ-aminopropyltriethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, etc. Aminosilanes; salts of inorganic acids (eg, hydrochloric acid, nitric acid, phosphoric acid, etc.) or organic acids (eg, formic acid, acetic acid, propionic acid, etc.), such as ammonia, trimethylamine, triethylamine, n-butylamine, or inorganic or organic acids Examples thereof include metathesis salts of salts and quaternary ammonium salts. These types and addition amounts are not limited at all.

  In addition to the above-mentioned components, the silicone-based coating agent (1) may optionally contain a filler other than colloidal silica (for example, inorganic filler such as alumina sol or fumed silica), a colorant, a diluting solvent, a thickening agent. One or more kinds of various additives such as an agent and a surfactant can be blended. Although it does not specifically limit as this dilution solvent, For example, alcohols, such as methanol, ethanol, isopropanol (IPA); Cellosolves, such as ethylene glycol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, etc. can be mentioned, These are 1 type or Two or more kinds can be used in combination.

  The silicone-based coating agent (1) can be stably used within the aforementioned molecular weight range by adjusting its pH value to 3.8 to 6.0. If the pH value is outside this range, the silicone-based coating agent (1) becomes less stable, and the usable period after preparing the silicone-based coating agent (1) may be limited. Here, the pH value adjusting method is not particularly limited. For example, when the pH value becomes less than 3.8 when the raw material of the silicone-based coating agent (1) is mixed, the basic range such as ammonia may be used. What is necessary is just to adjust to the inside pH value, and what is necessary is just to adjust to the said predetermined range using acidic reagents, such as hydrochloric acid, when pH value exceeds 6.0. Depending on the pH value, the reaction does not proceed conversely with a small molecular weight, and if it takes time to reach the molecular weight range, the silicone coating agent (1) is heated to promote the reaction. Alternatively, the pH value may be lowered with an acidic reagent and the reaction may be advanced, and then returned to a predetermined pH value with a basic reagent.

  Even when the pH value is adjusted as described above, or even when the pH value is not adjusted, the condensation reaction is promoted by adding a basic catalyst to the silicone-based coating agent (1) during use or at least during use. Since the number of crosslinking points in the coating film can be increased, it is possible to stably obtain a coating film having good crack resistance. Further, by promoting the crosslinking reaction, the curing time can be shortened or the curing temperature can be lowered, which is economical.

Of the two types of silicone coating agents disclosed in JP-A-9-249822, the other silicone coating agent (hereinafter referred to as silicone coating agent (2)) is:
Formula (R ³ ) _n SiX _4-n (7)
(In Formula (7), R ³ represents a substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms, X represents a hydrolyzable group, and n is an integer of 0 to 3. )
A silica-dispersed oligomer solution of organosilane (G) obtained by partially hydrolyzing the hydrolyzable organosilane represented by the formula (I) with colloidal silica dispersed in an organic solvent and / or water;
Average composition formula (R ⁴ ) _d Si (OH) _e O _{(4-de) / 2} (8)
(In Formula (8), R ⁴ represents a substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms, and d and e are 0.2 ≦ d ≦ 2.0 and 0.0001 ≦, respectively. (It is a number that satisfies the relationship of e ≦ 3 and d + e <4.)
A polyorganosiloxane (H) containing a silanol group in the molecule represented by:
Of the curing catalyst (I),
A silicon alkoxide coating agent containing three components (G), (H), and (I) as essential components is blended with an ultraviolet absorber.

  The silica-dispersed oligomer of component (G) used in the silicone-based coating agent (2) is a main component of a base polymer having a hydrolyzable group X as a functional group that is subjected to a curing reaction during film formation. This is achieved by adding one or more hydrolyzable organosilanes represented by the above general formula (7) to colloidal silica dispersed in an organic solvent, water, or a mixed solvent thereof, to form colloidal silica. It can be obtained by partially hydrolyzing the hydrolyzable organosilane with water therein or water added separately.

R ³ in the hydrolyzable organosilane represented by the general formula (7) is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms, such as a methyl group, an ethyl group, a propyl group, Alkyl groups such as butyl group, pentyl group, hexyl group, heptyl group and octyl group; cycloalkyl groups such as cyclopentyl group and cyclohexyl group; aralkyl groups such as 2-phenylethyl group and 3-phenylpropyl group; phenyl group and tolyl Aryl groups such as vinyl groups; alkenyl groups such as vinyl groups and allyl groups; halogen-substituted hydrocarbon groups such as chloromethyl groups, γ-chloropropyl groups, and 3,3,3-trifluoropropyl groups; γ-methacryloxypropyl groups Substituted hydrocarbon such as γ-glycidoxypropyl group, 3,4-epoxycyclohexylethyl group, γ-mercaptopropyl group, etc. It can be exemplified, and the like. Among these, an alkyl group having 1 to 4 carbon atoms and a phenyl group are preferable because of easy synthesis or availability.

  Examples of the hydrolyzable group X in the general formula (7) include an alkoxy group, an acetoxy group, an oxime group, an enoxy group, an amino group, an aminoxy group, and an amide group. Among these, an alkoxy group is preferable because it is easily available and a silica-dispersed oligomer solution (G) can be easily prepared. Examples of the hydrolyzable organosilane include mono-, di-, tri-, and tetra-functional alkoxysilanes in which the n in the general formula (7) is an integer of 0 to 3, acetoxy Examples thereof include silanes, oxime silanes, enoxysilanes, aminosilanes, aminoxysilanes, and amidosilanes. Among these, alkoxysilanes are preferable because they are easily available and the silica-dispersed oligomer solution (G) is easy to prepare.

  In particular, tetramethoxysilane, tetraethoxysilane, and the like can be exemplified as the n = 0 tetraalkoxysilane, and the methyltrialkoxysilane, methyltriethoxysilane, methyltrimethoxysilane, and the like can be exemplified as the n = 1 organotrialkoxysilane. Examples thereof include isopropoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane and the like. Examples of n = 2 diorganodialkoxysilanes include dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, and methylphenyldimethoxysilane. Further, examples of the triorganoalkoxysilane with n = 3 include trimethylmethoxysilane, trimethylethoxysilane, trimethylisopropoxysilane, and dimethylisobutylmethoxysilane. Organosilane compounds generally called silane coupling agents can also be used as alkoxysilanes.

  Of these hydrolyzable organosilanes of the general formula (7), 50 mol% or more is preferably a trifunctional compound represented by n = 1. More preferably, it is 60 mol% or more, and most preferably 70 mol% or more. When the trifunctional compound with n = 1 is less than 50 mol%, it is difficult to obtain a sufficient coating film hardness, and the dry curability tends to be inferior.

  As the colloidal silica used in the component (G), water-dispersible or non-aqueous organic solvent-dispersible colloidal silica such as alcohol can be used, and the colloid used in the silicone-based coating agent (1) described above. The same silica gel can be used. Generally, such colloidal silica contains 20 to 50% by weight of silica as a solid content, and the amount of silica can be determined from this value.

  When water-dispersible colloidal silica is used, water present as a component other than the solid content can be used for hydrolysis of the component (G). Water-dispersible colloidal silica is usually made from water glass, but such colloidal silica is readily available commercially. The organic solvent-dispersible colloidal silica can be easily prepared by replacing the water of the water-dispersible colloidal silica with an organic solvent. Such an organic solvent-dispersible colloidal silica can be easily obtained as a commercial product in the same manner as the water-dispersible colloidal silica. Examples of the organic solvent in which the colloidal silica is dispersed include, for example, lower aliphatic alcohols such as methanol, ethanol, isopropanol, n-butanol, and isobutanol; ethylene glycol, ethylene glycol monobutyl ether, and ethylene glycol monoethyl ether acetate. Examples include ethylene glycol derivatives; diethylene glycol derivatives such as diethylene glycol and diethylene glycol monobutyl ether, and diacetone alcohol. One or two or more selected from the group consisting of these can be used, but in combination with these hydrophilic organic solvents, toluene, xylene, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, Methyl ethyl ketoxime can also be used.

  The colloidal silica in the component (G) is essential for increasing the hardness of the cured film of the silicone coating agent (2). In the component (G), the colloidal silica is preferably contained in the range of 5 to 95% by weight as the silica solid content. More preferably, it is 10 to 90 weight%, Most preferably, it is the range of 20 to 85 weight%. If the content is less than 5% by weight, the desired film hardness cannot be obtained, and if it exceeds 95% by weight, it is difficult to uniformly disperse the silica, which may cause inconveniences such as gelation in the component (G). .

  The silica-dispersed oligomer of organosilane as component (G) is usually a partial hydrolysis of hydrolyzable organosilane of general formula (7) in at least one of water-dispersible colloidal silica and organic solvent-dispersible colloidal silica. Can be obtained. The amount of water used relative to the hydrolyzable organosilane is preferably 0.001 to 0.5 mol of water with respect to 1 mol of the hydrolyzable group. If the amount of water used is less than 0.001 mol, a sufficient partial hydrolyzate cannot be obtained, and if the amount of water used exceeds 0.5 mol, the stability of the partial hydrolyzate may be deteriorated. There is. The method of partial hydrolysis is not particularly limited, and a hydrolyzable organosilane and colloidal silica may be mixed and mixed with a necessary amount of water. At this time, the partial hydrolysis reaction proceeds at room temperature. In order to promote the partial hydrolysis reaction, it may be heated to 60 to 100 ° C. Furthermore, hydrochloric acid, acetic acid, halogenated silane, chloroacetic acid, citric acid, benzoic acid, dimethylmalonic acid, formic acid, propionic acid, glutaric acid, glycolic acid, maleic acid, malonic acid, toluene for the purpose of promoting partial hydrolysis reaction An inorganic acid such as sulfonic acid or oxalic acid or an organic acid may be used as a catalyst.

  The silica-dispersed oligomer of organosilane as component (G) has a liquid pH value in the range of 2.0 to 7.0, more preferably 2.5 to 6.5, in order to obtain long-term stable performance. It is better to adjust to a range of pH 3.0 to 6.0, even more preferably in the range of 3.0 to 6.0. When the pH value is out of this range, the long-term performance deterioration of the component (G) may be significant particularly when the amount of water used is 0.3 mol or more with respect to X1 mol. If the pH value of the component (G) is outside this range, the pH value may be adjusted by adding a basic reagent such as ammonia or ethylenediamine when the pH value is more acidic than this range. What is necessary is just to adjust pH value using acidic reagents, such as hydrochloric acid, nitric acid, and an acetic acid. The adjustment method is not particularly limited.

The (H) component silanol group-containing polyorganosiloxane used in the silicone-based coating agent (2) has an average composition formula represented by the above formula (8), and R ⁴ in the formula (8) is: it can be exemplified the same as ^{R 3} above (7) wherein 5 to 50 wt% in ^{R 4} is a phenyl group. If the phenyl group is less than 5% by weight, the elongation of the coating film is reduced and cracks are likely to occur, and if it exceeds 50% by weight, curing may be too slow. The other R ⁴ is preferably an alkyl group having 1 to 4 carbon atoms, a vinyl group, a γ-glycidoxypropyl group, a γ-methacryloxypropyl group, a γ-aminopropyl group, 3,3,3-trifluoropropyl. Substituted hydrocarbon groups such as groups, more preferably alkyl groups of methyl and ethyl groups. In the formula (8), d and e are numbers satisfying the relations 0.2 ≦ d ≦ 2.0, 0.0001 ≦ e ≦ 3, and d + e <4, respectively, and d is less than 0.2 or e is If it exceeds 3, there are disadvantages such as cracks in the cured film, and if d is more than 2 and 4 or less, or if e is less than 0.0001, curing does not proceed well.

  Such a silanol group-containing polyorganosiloxane (H) of the formula (8) is, for example, methyltrichlorosilane, dimethyldichlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, or one or two alkoxysilanes corresponding thereto. The above mixture can be obtained by hydrolyzing with a large amount of water by a known method. In order to obtain a silanol group-containing polyorganosiloxane, when it is hydrolyzed by a known method using alkoxysilane, an unhydrolyzed alkoxy group may remain in a trace amount. That is, a polyorganosiloxane in which a silanol group and a trace amount of an alkoxy group coexist may be obtained, but such a polyorganosiloxane may be used.

  The molecular weight of the silanol group-containing polyorganosiloxane as the component (H) is preferably 700 to 20000. The molecular weight here is a weight average molecular weight in terms of standard polystyrene by GPC (gel permeation chromatography) measurement. When the molecular weight is less than 700, the curability of the formed coating film is slow and cracks are likely to occur. When it exceeds 20000, there is a possibility that the coating film formed from the silicone-based coating agent (2) to which the pigment is added has no gloss and the smoothness is also deteriorated.

  The curing catalyst of the component (I) used in the silicone-based coating agent (2) accelerates the condensation reaction between the component (G) and the component (H) and cures the film. Examples of such catalysts include metal salts of carboxylic acids such as alkyl titanates, tin octylate and dibutyltin dilaurate, dioctyltin dimaleate; amine salts such as dibutylamine-2-hexoate, dimethylamine acetate, and ethanolamine acetate; Carboxylic acid quaternary ammonium salts such as tetramethylammonium acetate; amines such as tetraethylpentamine; N-β-aminoethyl-γ-aminopropyltrimethoxysilane, N-β-aminoethyl-γ-aminopropylmethyl Amine-based silane coupling agents such as dimethoxysilane; acids such as p-toluenesulfonic acid, phthalic acid and hydrochloric acid; aluminum compounds such as aluminum alkoxide and aluminum chelate; alkali catalysts such as potassium hydroxide; tetraisopropyl titanate; There are titanium compounds such as trabutyl titanate and titanium tetraacetylacetonate, and halogenated silanes such as methyltrichlorosilane, dimethyldichlorosilane, and trimethylmonochlorosilane. In addition to these, (G) component and (H) component There is no particular limitation as long as it is effective for the condensation reaction.

  The mixing ratio of the component (G) and the component (H) is 99 to 1 part by weight of the component (H) with respect to 1 to 99 parts by weight of the component (G), preferably 5 to 95 parts by weight of the component (G). In contrast, 95 to 5 parts by weight of component (H), more preferably 90 to 10 parts by weight of component (H) with respect to 10 to 90 parts by weight of component (G) (provided that component (G) and component (H)) Total amount of 100 parts by weight). When the component (G) is less than 1 part by weight, the room temperature curability is inferior and sufficient film hardness cannot be obtained. On the other hand, when the component (G) exceeds 99 parts by weight, the curability is unstable and a good film may not be obtained.

  Moreover, it is preferable that the addition amount of the curing catalyst of (I) component is 0.0001-10 weight part with respect to a total of 100 weight part of (G) component and (H) component. More preferably, it is 0.0005-8 weight part, Most preferably, it is 0.0007-5 weight part. If the addition amount of the curing catalyst (I) is less than 0.0001 parts by weight, it may not be cured at room temperature, and if the addition amount of the curing catalyst (I) exceeds 10 parts by weight, the heat resistance and weather resistance of the film may be reduced. It may get worse.

  You may add a pigment, a matting agent, a filler, etc. to the silicone type coating agent (1) or (2) prepared as mentioned above. Examples of pigments to be added include organic pigments such as carbon black, quinacridone, naphthol red, cyanine blue, cyanine green, and hansa yellow, titanium oxide, barium sulfate, petal, calcium carbonate, alumina, iron oxide red, and composite metal oxide. An inorganic pigment such as a product is good, and one or two or more selected from these groups can be used in combination. Among these, inorganic pigments are preferable for improving weather resistance. Moreover, silica powder, barium sulfate, etc. can be used as a filler, and it can be used combining 1 type (s) or 2 or more types chosen from the group enumerated above. The particle diameter of the pigment or filler is not particularly limited, but is preferably about 0.01 to 4 μm in average particle diameter.

  The amount of pigment added is not particularly limited because the concealability varies depending on the type of pigment, but in the case of an inorganic pigment, a range of 15 to 80 parts by weight with respect to 100 parts by weight of the resin solid content is preferable. When the amount is less than 15 parts by weight, the concealability cannot be sufficiently obtained, and when it exceeds 80 parts by weight, the smoothness of the coating film may be deteriorated. The pigment can be dispersed by an ordinary method, and a dispersant, a dispersion aid, a thickener, a coupling agent, and the like can be used at that time.

  And an ultraviolet-absorbing coating agent can be obtained by adding an ultraviolet absorber to a silicone type coating agent (1) or (2). Examples of ultraviolet absorbers include organic ultraviolet absorbers such as benzotriazole compounds such as 2 (2′hydroxy-5-methylphenyl) benzotriazole, benzophenone compounds such as 2,4-dihydroxybenzophenone, and particulate zinc oxide. And an inorganic ultraviolet absorber such as fine particle titanium oxide can be used, and an organic ultraviolet absorber and an inorganic ultraviolet absorber can be used in combination.

  The organic ultraviolet absorber can be relatively easily dispersed in the silicone coating agent (1) or (2). The addition amount of the organic ultraviolet absorber is not particularly limited, but is in the range of 0.1 to 30% by weight as the solid content with respect to the solid content of the silicone coating agent (1) or (2). Is preferred. If the addition amount is less than 0.1% by weight, the effect of improving the weather resistance due to UV cut becomes insufficient, and if it exceeds 30% by weight, the color of the organic ultraviolet absorber becomes strong, which is not preferable.

  The addition amount of fine particle zinc oxide and fine particle titanium oxide which are inorganic ultraviolet absorbers is not particularly limited, but is 0.1 to 20 with respect to the solid content of the silicone coating agent (1) or (2). A range of% by weight is preferred. If the added amount is less than 0.1% by weight, the effect of improving the weather resistance due to UV cut becomes insufficient, and if it exceeds 20% by weight, it becomes cloudy white.

  Here, the ultraviolet absorber generally has a function of absorbing ultraviolet light and converting it into heat, and the organic ultraviolet absorber has a lifetime because this function is reduced over a long period of time. On the other hand, the lifetime of the inorganic ultraviolet absorber is semi-permanent, and it is preferable to use an inorganic ultraviolet absorber such as fine particle zinc oxide or fine particle titanium oxide as the ultraviolet absorber. However, fine particle zinc oxide and fine particle titanium oxide have poor dispersibility in the silicone-based coating agent (1) or (2), and agglomerate and the coating film becomes cloudy white. is there. In addition, fine zinc oxide and fine titanium oxide powders have a photocatalytic action. When an acrylic resin or alkyd resin having low weather resistance is used, the resin itself deteriorates and long-term storage stability cannot be obtained. For this reason, it is conceivable to use fine zinc oxide or fine particle titanium oxide dispersed in a solvent. However, fine zinc oxide or fine particle titanium oxide settles quickly in the solvent, and it is difficult to improve the dispersibility by this method.

On the other hand, in the hydrolyzable organosilane represented by the general formula (R ³ ) _n SiX _4-n used in the silica-dispersed oligomer solution of organosilane (G), fine zinc oxide and fine titanium oxide are easily dispersed. This dispersion is excellent in transparency and long-term storage stability. Therefore, it is preferable to use the hydrolyzable organosilane in a state in which fine particle zinc oxide or fine particle titanium oxide is added and dispersed. In addition to adding particulate zinc oxide or particulate titanium oxide directly to hydrolyzable organosilane, (R ³ ) _n SiX _4-n hydrolyzable organosilane was prepared by partial hydrolysis in colloidal silica (G ) The silica dispersion oligomer solution of organosilane may be dispersed by adding fine particle zinc oxide or fine particle titanium oxide, and this silica dispersed oligomer solution in which fine particle zinc oxide or fine particle titanium oxide is dispersed is used as a silicone coating agent. By adding to (1) or (2), a coating agent containing fine zinc oxide or fine titanium oxide can be prepared. In this case, the particle size of the primary particles (non-aggregated particles) of fine particle zinc oxide or fine particle titanium oxide is preferably 0.01 μm to 0.5 μm, and the silica-dispersed oligomer solution of organosilane (G) Fine zinc oxide or fine titanium oxide can be dispersed up to about 200 parts by weight with respect to 100 parts by weight (when the amount exceeds 200 parts by weight, the viscosity increases and stirring becomes impossible). The dispersion can be performed using a general mixing apparatus such as a sand mill, a ball mill, or a paint shaker. At this time, an additive aid or filler may be added at a level that does not lower the weather resistance.

Next, in the present invention, the inorganic coating agent for forming the photocatalyst-containing inorganic coating film 4 is not particularly limited, but it is preferable to use a silicone-based coating agent containing a photocatalyst. As this silicone type coating agent, what is disclosed by patent 2767259 can be used, for example. That is,
General formula: Si (OR ¹ ) ₄ (9)
20 to 200 parts by weight of colloidal silica having an organic solvent dispersibility in which the silicon compound and / or colloidal silica is dispersed in a non-aqueous organic solvent,
General formula: R ² Si (OR ¹ ) ₃ (10)
100 parts by weight of a silicon compound represented by
General formula: R ² ₂ Si (OR ¹ ) ₂ (11)
And a photocatalyst-containing coating (in the above formulas (9) to (11), R ¹ and R ² represent a monovalent hydrocarbon group). An agent can be used.

Each silicon compound has a general formula represented by the following formula (12).
General formula: R ² _n Si (OR ¹ ) _4-n (12)
(In formula (12), n = 0 to 3 is shown, and R ¹ and R ² are monovalent hydrocarbon groups.)
R ¹ and R ^{2 in} formula (12) are not limited as long as they represent a monovalent hydrocarbon group, but R ² represents a substituted or unsubstituted hydrocarbon group having 1 to 8 carbon atoms. For example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group and other alkyl groups, cyclopentyl group, cyclohexyl group and other cycloalkyl groups, 2-phenylethyl group, 3-phenylpropylene. Halogens such as aralkyl groups such as ruthel groups, aryl groups such as phenyl and tolyl groups, anikenyl groups such as vinyl and allyl groups, chloromethyl groups, γ-chloropropyl groups, and 3,3,3-trifluoropropyl groups Examples thereof include substituted hydrocarbon groups and substituted hydrocarbon groups such as γ-methacryloxypropyl group, γ-glycidoxypropyl group, 3,4-epoxycyclohexylethyl group, and γ-mercaptopropyl group. Among these, an alkyl group having 1 to 4 carbon atoms and a phenyl group are preferable because of ease of synthesis or availability.

As R ¹ in the above formula (12), ^one having an alkyl group having 1 to 4 carbon atoms as a main raw material is used. In particular, tetramethoxysilane, tetraethoxysilane and the like are exemplified as the tetraalkoxysilane of n = 0, and methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane are exemplified as the organotrialkoxysilane of n = 1. , Phenyltrimethoxysilane, phenyltriethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane and the like. Further, examples of the n = 2 diorganodialkoxysilane include dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, methylphenyldimethoxysilane, and the like, and n = 3 triorganoalkoxysilane. Examples thereof include trimethylmethoxysilane, trimethylethoxysilane, trimethylisopropoxysilane, dimethylisobutylmethoxysilane and the like.

R ¹ and R ^{2 in the} above formulas (9), (10), and (11) may be the same hydrocarbon group or different.

  Preparation of the silicone-based coating agent includes, for example, diluting a silicon compound represented by the above formulas (9), (10), and (11) with a solvent, adding water or a catalyst as a curing agent, hydrolysis, and It is prepared by performing a polycondensation reaction. The weight average molecular weight (Mw) of these silicon compounds is calculated in terms of polystyrene. In this preparation, the weight average molecular weight (Mw) of the inorganic coating is made 900 or more in terms of polystyrene. When the weight average molecular weight (Mw) is less than 900 in terms of polystyrene, curing shrinkage increases during the polycondensation reaction, and cracks are likely to occur in the baked inorganic coating film.

  The silicone-based coating agent can be used in combination with the silicon compound represented by the above formula (9), or alternatively, colloidal silica as a component. The colloidal silica is an organic solvent-dispersible colloidal silica dispersed in a non-aqueous organic solvent such as alcohol. The colloidal silica contains 20 to 50% by weight of silica as a solid content. The organic solvent-dispersible colloidal silica can be easily prepared by replacing the organic solvent with water. Examples of the organic solvent in which the colloidal silica is dispersed include, for example, lower aliphatic alcohols such as methanol, ethanol, isopropanol, n-butanol, and isobutanol, ethylene glycol, ethylene glycol monobutyl ether, and ethylene glycol monoethyl ether acetate. And ethylene glycol derivatives, diethylene glycol derivatives such as diethylene glycol and diethylene glycol monobutyl ether, and diacetone alcohol. One or more of these are used. Furthermore, toluene, xylene, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, methyl ethyl ketoxime, etc. can be used in combination with a hydrophilic organic solvent. In addition, the said compounding quantity of the said colloidal silica is a weight also including a dispersion medium.

  Water is generally used as a curing agent in preparing the silicone coating agent, and the amount of this water is preferably 45% by weight or less, more preferably 25% by weight or less in the silicone coating agent.

  Examples of the organic solvent used in preparing the silicone coating agent include lower aliphatic alcohols such as methanol, ethanol, isopropanol, n-butanol, and isobutanol, ethylene glycol, ethylene glycol monobutyl ether, and ethylene glycol monoethyl acetate. Examples thereof include ethylene glycol derivatives such as ether, diethylene glycol derivatives such as diethylene glycol and diethylene glycol monobutyl ether, and diacetone alcohol. One or more of these are used. Furthermore, toluene, xylene, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, methyl ethyl ketoxime, etc. can be used in combination with a hydrophilic organic solvent.

  When preparing a silicone type coating agent, it is desirable to set pH of a silicone type coating agent to 3.8-6. Within this pH range, the preservability of the silicone-based coating agent is good, and when it is outside this pH range, the period during which application can be performed is limited. The method for adjusting the pH is not limited. For example, when the pH is less than 3.8 when the materials are mixed, the pH may be adjusted by adding a basic reagent such as ammonia. In this case, an acid reagent such as hydrochloric acid may be added for adjustment. Depending on the pH, if the reaction progresses slowly with a small molecular weight, the reaction may be promoted by heating, or after the reaction is advanced by lowering the pH with an acidic reagent, a basic reagent is added. It may be a predetermined pH.

  The silicone-based coating agent can be used as a photocatalytic silicone-based coating agent by containing a photocatalyst. Generally, titanium oxide is used as the photocatalyst. Zinc oxide, tin oxide, iron oxide, zirconium oxide, tungsten oxide, chromium oxide, molybdenum oxide, ruthenium oxide, germanium oxide, lead oxide, cadmium oxide, copper oxide, vanadium oxide, niobium oxide, tantalum oxide, manganese oxide, Cobalt oxide, rhodium oxide, rhenium oxide and the like can also be mentioned. Although the compounding quantity of a photocatalyst is not specifically limited, The range of 20 to 80 weight% is preferable with respect to the dry solid content of a silicone type coating agent.

  Then, after applying a primer treatment to the surface of the ceramic base material 1 as necessary, an organic coating agent 2 is applied and dried and cured thereon, and then an organic coating film 2 is formed thereon. An inorganic coating film 3 that does not contain a photocatalyst is formed by applying a system coating agent and drying and curing, and further, a photocatalyst-containing silicone coating agent is applied thereon and drying and curing to form an inorganic film 4 containing a photocatalyst. Thus, a coated body as shown in FIG. 1 can be obtained.

  The above coating agents can be applied by various methods such as brush coating method, dipping method, spray coating method, roll coating method, bell method, flow coating method, curtain coating method, knife coating method, etc. In order to easily obtain a coating film having a high surface roughness, it is preferable to perform coating by any one of a spray coating method, a roll coating method, and a bell method using a rotating cup.

  And this invention sets the surface roughness Ra of the inorganic coating film 3 formed by coating a silicone type coating agent on the organic coating film 2 as mentioned above in the range of 0.2-3 micrometers. It is. Here, the surface roughness Ra refers to the average arithmetic roughness (Ra) defined in JIA B0601.

In adjusting the surface roughness Ra of the inorganic coating film 3 to a range of 0.2 to 3 μm, when coating is performed by a roll coating method, the silicone coating agent is SiO ₂ , ZnO, TiO ₂ , CaCO ₃ , BaSO. It can be carried out by mixing and dispersing inorganic powder such as ₄ and adjusting the concentration of the inorganic powder in the coating agent. The particle size of the inorganic powder is arbitrary, but the effect of agglomeration of fine particles of about 0.1 μm may be used, and the surface of the coating film is made uneven by using particles of about 10 μm. You may make it matt.

  In addition, when the application is performed by the spray method or the bell method, the surface roughness Ra can be similarly adjusted by mixing and dispersing the inorganic powder in the silicone-based coating agent. Since unevenness can be given by so-called “application in a dry mist state” in which the mist is applied in a high NV (solid content concentration) state, the surface roughness Ra of the inorganic coating film 3 is adjusted using this method. Can be performed. In this case, it may be possible to apply an originally high NV, but if the NV is high, the spraying or bell application may be disturbed, so the gun distance or the rotation speed of the bell may be adjusted. It is preferable to adjust the dry mist.

  Thus, by forming the surface roughness Ra of the inorganic coating film 3 to 0.2 to 3 μm, the photocatalyst-containing inorganic coating film 4 and the inorganic coating film formed by coating the photocatalyst-containing silicone coating agent thereon. The contact area between the inorganic coating film 3 and the photocatalyst-containing inorganic coating film 4 is increased, and the adhesion of the photocatalyst-containing inorganic coating film 4 to the inorganic coating film 3 can be increased. The durability of the coating film can be increased. And the unevenness | corrugation which received the surface roughness of the inorganic coating film 3 will be formed in the surface of the photocatalyst containing inorganic coating film 4, the surface area of the photocatalyst containing coating film 4 becomes large, and the surface of the photocatalyst containing inorganic coating film 4 As a result, the photocatalytic effect produced by the process increases and the antifouling property is improved.

  When the surface roughness Ra of the inorganic coating film 3 is less than 0.2 μm, the effect of increasing the contact area between the inorganic coating film 3 and the photocatalyst-containing inorganic coating film 4 and unevenness on the surface of the photocatalyst-containing inorganic coating film 4 The effect to form becomes inadequate and the effect of said adhesive improvement and antifouling improvement cannot fully be acquired. On the other hand, if the surface roughness Ra of the inorganic coating film 3 exceeds 3 μm, the surface roughness of the photocatalyst-containing inorganic coating film 4 that has received the surface roughness of the inorganic coating film 3 becomes too large, which may impair the appearance of the coating. There is.

  In addition, when the inorganic coating film 3 is formed by applying the silicone coating agent on the organic coating film 2 as described above, the silicone coating agent is applied and then baked at a baking energy of 5000 ° C. · sec or more. It is preferable to form the inorganic coating film 3. This baking energy is indicated by the product of the temperature (° C.) and baking time (sec) of the ceramic base material 1 when heated and baked after applying the silicone coating agent, and the baking temperature is 60 ° C. or higher. It is desirable that Therefore, for example, when the baking temperature is 100 ° C., the baking time needs to be set to 50 sec or more. The upper limit of the baking energy is not particularly set, but is practically about 20000 ° C. · sec.

  Thus, the inorganic coating film 3 can be sufficiently baked and hardened by forming the inorganic coating film 3 by baking the coating film of the silicone coating agent at a baking energy of 5000 ° C. · sec or more. In forming the photocatalyst-containing inorganic coating film 4 by coating the coating film 3 with a photocatalyst-containing silicone-based coating agent, there is no mixing at the layer interface between the inorganic coating film 3 and the photocatalyst-containing inorganic coating film 4. The effect of the photocatalyst in the contained inorganic coating film 4 can be sufficiently exerted, and the antifouling property by the photocatalyst can be enhanced. When the baking energy is less than 5000 ° C. · sec, the inorganic coating film 3 is insufficiently baked and solidified, and when the photocatalyst-containing silicone coating agent is applied thereon to form the photocatalyst-containing inorganic coating film 4 The inorganic coating film 3 may be dissolved by the solvent in the photocatalyst-containing silicone coating agent, and the photocatalyst contained in the photocatalyst-containing silicone coating agent may be embedded in the layer of the inorganic coating film 3. There exists a possibility that the photocatalytic action by the coating film 4 may become inadequate.

  Next, the present invention will be specifically described with reference to examples.

(Preparation of organic coating agent)
(Organic coating agent)
As an organic coating agent, a core-shell type acrylic emulsion paint (manufactured by Kansai Paint Co., Ltd.) was used.

(Preparation of silicone coating agent)
100 parts by weight of methyltrimethoxysilane, 20 parts by weight of tetraethoxysilane, 150 parts by weight of isopropyl alcohol organosilica sol (“OSCAL1432” manufactured by Catalyst Chemical Industry Co., Ltd., SiO ₂ content 30% by weight), 40 parts by weight of dimethyldimethoxysilane and Silicon alkoxide was prepared by mixing 100 parts by weight of isopropyl alcohol, adding 200 parts by weight of water and stirring the mixture, and adjusting the weight average molecular weight Mw to 1200 in a thermostatic bath at 60 ° C.

  Then, by adding a benzotriazole-based ultraviolet absorber (“Tinubin 384” manufactured by Ciba Geigy Co., Ltd.) in a blending amount of 5% by mass to the silicon alkoxide and stirring, a silicone-based coating containing ultraviolet absorption An agent was obtained. In addition, in order to adjust the surface roughness Ra of the inorganic coating film, silica (SiO2: secondary particle size 1 to 7 μm) is added to the silicone-based coating agent in the addition amount (relative to the solid content) shown in Table 1. did.

(Preparation of photocatalyst-containing silicone coating agent)
After mixing 100 parts by weight of methyltrimethoxysilane with 10 parts by weight of tetraethoxysilane, 90 parts by weight of IPA organosilica sol, 30 parts by weight of dimethyldimethoxysilane and 100 parts by weight of isopropyl alcohol (IPA), 90 parts by weight of water is added. , Stirred. The weight average molecular weight Mw was adjusted to 1500 in a constant temperature bath at 60 ° C.

  Then, 20 parts by weight of titanium oxide was added to the prepared liquid and stirred to obtain a photocatalyst-containing silicone-based coating agent.

(Examples 1-11 and Comparative Examples 1-6)
The organic coating agent was applied to the surface of the ceramic ceramic substrate 1 by a spray method and baked at 150 ° C. for 5 minutes to form an organic coating film 2 having a thickness of 30 μm.

  Next, the above-mentioned silicone-based coating agent was applied thereon by the coating method shown in Table 1, and baked at 150 ° C. for 7 minutes to form an inorganic coating film 3 having a thickness shown in Table 1. The surface roughness Ra of the inorganic coating film 3 was measured, and the results are shown in Table 1. Here, the surface roughness Ra was measured using a profile micrometer “VF7510 / 7500” manufactured by Keyence Corporation.

  Further on this, the photocatalyst-containing silicone coating agent was applied by a spray method and baked at 150 ° C. for 1 minute to form a photocatalyst-containing inorganic coating film 4 having a film thickness shown in Table 1.

For the coated body thus obtained, the following characteristics were measured, and the results are shown in Table 1.
・ Appearance (JIS K5600-4-3)
A photocatalyst-containing silicone coating agent was applied to a glass plate (Matsunami slide glass) in the same manner as described above to form a photocatalyst-containing inorganic coating film. The appearance was visually observed and evaluated as follows.
○: Transparent, Δ: Slightly cloudy, ×: White turbidity / Coating film adhesion (JIS K5600-5-6)
A test was performed by applying a 1 mm square cross cut to the coating film, and classifications 0 and 1 were evaluated as ◯, 2 as Δ, and 3 to 5 as X.
・ Hydrophilicity After irradiating the coated body with a black light manufactured by Toshiba Corp. at an illuminance of 1.0 ± 0.05 mW / cm ² for 96 hours, water was measured with a static contact angle measuring instrument (“DM700” manufactured by Kyowa Interface Science). The contact angle was measured and evaluated as follows.
○: Contact angle of 10 degrees or less, Δ: Contact angle of 40 degrees or less, X: Contact angle of greater than 40 degrees ・ NOx decomposition performance After irradiating the coated body with a black light manufactured by Toshiba Corporation for 96 hours, this coated body and NO gas A solution prepared by diluting (purity 99.9%, manufactured by Sumitomo Seika Co., Ltd.) in the atmosphere to a concentration of 10 ppm was sealed in a Tedlar pack, and the NO concentration in the Tedlar pack was measured. Concentration measurement is performed using a NO gas detector tube (Gastec's gas detector tube “11L”), and 30 minutes while irradiating a Toshiba black light with an illuminance of 1.0 ± 0.05 mW / cm ^2. Measured every time and finished in 120 minutes. At this time, the residual NO concentration of the Tedlar pack was evaluated as follows.
○: 0 to less than 2 ppm, Δ: 2 to less than 8 ppm, x: 8 to 10 ppm
・ Crack resistance After 30 cycles of hot water air drying test (1 cycle: 60 ° C hot water immersion for 8 hours + air drying at room temperature) on the coated body, the appearance of the coating film was visually observed and evaluated as follows. did.
○: No crack, △: Slightly cracked, ×: Significant crack / weather resistance After a 5000 hour test with a sunshine weather meter, the appearance of the coating film on the coated body was observed visually, as follows: Evaluated.
×: Significant change, △: Slight change, ○: Slight change

  As can be seen in Table 1, it is confirmed that the examples of the examples in which the surface roughness Ra of the inorganic coating film 3 is set to 0.2 to 3 μm are excellent in coating film adhesion and coating film appearance. .

It is the schematic which shows the coating-film structure of a coating body.

Explanation of symbols

1 Ceramic Base Material 2 Organic Coating 3 Inorganic Coating 4 Photocatalyst-Containing Inorganic Coating

Claims (4)

  A coated body in which each coating film is formed in the order of an organic coating film, an inorganic coating film, and a photocatalyst-containing inorganic coating film on the surface of a ceramic base material, and the surface roughness Ra of the inorganic coating film is 0.2 to 3 μm. The painted body characterized by being.   The coated body according to claim 1, wherein the inorganic coating film and the photocatalyst-containing inorganic coating film are formed by coating with a silicone-based coating agent.   The coated body according to claim 1 or 2, wherein the organic coating film is formed by painting an organic coating agent mainly comprising at least one of an acrylic emulsion and an acrylic silicone emulsion. The coated body according to claim 2 or 3, wherein the inorganic coating film is formed by applying a silicone-based coating agent and baking with a baking energy of 5000 ° C · sec or more.

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