JP2011098282A - Method for coating substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new method for coating a substrate which holds adhesion of a coating film to a substrate, when forming the coating film containing a fluorine-based resin on the substrate. <P>SOLUTION: On the substrate, a first coating film is formed which is made of a first coating material, at least one of acrylic silicone based coating material and a coating material containing a silane coupling agent. And then, on the first coating film, a second coating film is formed which is made of a second coating material containing a fluorine resin, hardening agent, and silicate compound. Alternatively, on the substrate, a coating film is formed which is made of a coating material containing a fluorine resin, hardening agent, silicate compound, and silane coupling agent. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for coating a base material used for industrial and industrial purposes with a cured coating film of a paint containing a fluororesin.

  In recent years, a cured coating film having various functions is formed on a glass substrate to form a laminate composed of the glass substrate and the cured coating film. The laminate is used for various industrial applications by utilizing the characteristics of the cured coating film. In particular, a laminate formed by forming a coating film containing a fluorine-based resin with respect to a glass substrate, by taking into consideration the characteristics such as low contamination, weather resistance, and light transmittance of the coating film, It is also used for architectural outer walls, windows, solariums, etc., and as a transparent substrate and antiglare film for solar cell modules.

  However, the adhesion between the glass substrate and the fluororesin coating film is not sufficient, and the problem that the fluororesin coating film is peeled off from the glass substrate frequently occurs.

  In view of such a problem, in Patent Documents 1 and 2, an interface treatment is performed on the surface of the glass substrate on which the fluororesin coating film is to be formed, and the interface treatment is performed. It is disclosed to form the fluororesin coating film on the rear surface. However, these documents merely disclose that the surface treatment is performed using the surface treatment agent, and there is no specific disclosure of the kind of the surface treatment agent and the treatment method. In addition, it does not teach at all how much the adhesion between the glass substrate and the fluororesin coating film is improved by such an interface treatment.

  Therefore, in the conventional techniques including the above-mentioned Patent Documents 1 and 2, there is no disclosure about a specific technique for improving the adhesion in the case of forming a fluorine-based resin on a glass substrate. I don't teach.

JP 2001-53315 A JP 2001-53317 A

  In view of the above problems, the present invention provides adhesion between the substrate and the coating film, that is, adhesion of the coating film to the substrate, when forming a coating film containing a fluororesin on the substrate. An object of the present invention is to provide a novel method for coating a base material that can be held.

  In order to solve the above-mentioned problems, the present invention is a method for coating a base material, wherein a first coating comprising at least one of an acrylic silicone paint and a silane coupling agent-containing paint on the base material. A step of forming a film, and a step of forming a second coating film comprising a second coating material containing a fluororesin, a curing agent, and a silicate compound on the first coating film. And a substrate coating method (first coating method).

  Further, the present invention is a method for coating a base material, comprising the step of forming a coating film comprising a paint containing a fluororesin, a curing agent, a silicate compound, and a silane coupling agent on the base material. The present invention relates to a substrate coating method (second coating method).

  According to the first coating method, an acrylic silicone paint and a silane cup are provided between the second coating film made of a so-called fluororesin and containing the fluororesin formed on the base material and the base material. A first coating film containing at least one of the ring agents is formed. The acryl silicone-based paint and the silane coupling agent are strong between the base material and the second coating film through functional groups such as hydroxyl groups on the surface of the base material and hydroxyl groups on the surface of the second coating film. It is thought to form a siloxane bond. Therefore, the first coating film functions as an adhesion enhancement layer, and the adhesion of the second coating film to the substrate can be improved.

  Further, according to the second coating method, the silane coupling agent is directly contained in the fluororesin. Therefore, in this case, the coating film made of the fluororesin directly forms a strong siloxane bond with the hydroxyl group of the substrate, so that the adhesion between the coating film and the substrate is improved. It is thought that it becomes.

  The second coating film of the first coating method and the curing agent contained in the coating film of the second coating method are for curing the fluororesin that is the main component constituting these coating films. The hardness and the like of these coating films can be controlled by appropriately adjusting the type and content of the curing agent.

  Furthermore, the silicate compound contained in the second coating film of the first coating method and the coating film of the second coating method is for imparting low contamination to these coating films. That is, since these coating films contain a silicate compound, moisture in the air and Si—OH groups or Si—O—Si bonds are formed, so that the hydrophilicity of the surface increases and the attached dirt is removed by water. It is thought that it originates in being able to remove by etc.

  In one embodiment of the present invention, the second coating film of the first coating method and the coating film of the second coating method can contain a non-fluorine resin for the purpose of cost reduction or the like. .

  Furthermore, in one embodiment of the present invention, when it is desired to impart ultraviolet absorptivity to the second coating film of the first coating method and the coating film of the second coating method, an ultraviolet absorber is added to these coating films. It can be included. Moreover, when it is desired to impart matting properties to the coating film, a matting agent can be contained in these coating films.

  As described above, according to the present invention, when a coating film containing a fluororesin is formed on a substrate, the adhesion between the substrate and the coating film, that is, the coating film with respect to the substrate. It is possible to provide a novel method for coating a base material that can maintain adhesion.

  The details of the present invention as well as other features and advantages are described below.

(Base material)
Examples of the base material that can be used in the present invention include glass base materials, plastics, plastic films, metals, and the like. A strong siloxane bond via a functional group such as a hydroxyl group on the surface of the material and a hydroxyl group on the surface of the second coating film, or a coating film made of a fluororesin directly forms a strong siloxane bond with a hydroxyl group of the substrate. Therefore, it is considered that the adhesion between the base material and the coating film made of the fluororesin resin can be improved.

(Fluorine resin)
The fluororesin is a main component of the second coating film of the first coating method and the coating film of the second coating method, which is formed by the coating method of the present invention.

  As the fluororesin, a fluoroolefin copolymer is preferable. The fluoroolefin copolymer is a copolymer of a fluoroolefin and another polymerizable monomer copolymerizable with the fluoroolefin. Another polymerizable monomer may be used individually by 1 type, and may be used in combination of 2 or more type.

  Examples of the fluoroolefin composing the fluoroolefin copolymer include C2-C3 fluoroolefins such as tetrafluoroethylene, chlorotrifluoroethylene, hexafluoropropylene, vinylidene fluoride, and vinyl fluoride.

  The proportion of the polymer units based on the fluoroolefin in the fluoroolefin copolymer is preferably 20 to 70 mol% from the viewpoint of obtaining sufficient weather resistance.

  As another polymerizable monomer constituting the fluoroolefin copolymer, a vinyl monomer, that is, a compound having a carbon-carbon double bond is preferable. Examples of vinyl monomers include vinyl ether, allyl ether, carboxylic acid vinyl ester, carboxylic acid allyl ester, and olefin.

  Examples of the vinyl ether include cycloalkyl vinyl ethers such as cyclohexyl vinyl ether; alkyl vinyl ethers such as nonyl vinyl ether, 2-ethylhexyl vinyl ether, hexyl vinyl ether, ethyl vinyl ether, n-butyl vinyl ether, and t-butyl vinyl ether.

  Examples of allyl ethers include alkyl allyl ethers such as ethyl allyl ether and hexyl allyl ether.

  Examples of the carboxylic acid vinyl ester or the carboxylic acid allyl ester include vinyl esters or allyl esters of carboxylic acids such as acetic acid, butyric acid, pivalic acid, benzoic acid, and propionic acid. As the carboxylic acid vinyl ester, commercially available products such as Veova-9 and Veova-10 (both manufactured by Shell Chemical Co., Ltd.) may be used as vinyl esters of carboxylic acids having a branched alkyl group.

  Examples of olefins include ethylene, propylene and isobutylene. Further, the fluoroolefin copolymer is preferably a fluoroolefin copolymer having a functional group capable of forming a crosslink by reacting with a curing agent described later. The type of the functional group can be appropriately selected depending on the combination with the curing agent. Representative examples include a hydroxyl group, a carboxy group, a hydrolyzable silyl group, an epoxy group, and an amino group.

  As a method for introducing a functional group, a method in which a monomer having a functional group is used as the other copolymerizable monomer for copolymerization, or a method for introducing the monomer by reacting the polymer with a polymer after polymerization. Is mentioned.

Examples of the monomer having a functional group include the following.
That is, hydroxyalkyl vinyl ethers such as 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether and cyclohexanediol monovinyl ether, which are monomers having a hydroxyl group; hydroxyalkyl allyl ethers such as 2-hydroxyethyl allyl ether; or vinyl hydroxyalkyl crotonates Examples thereof include vinyl esters or allyl esters of hydroxyl group-containing carboxylic acids such as crotonic acid and undecenoic acid, which are monomers having a carboxy group.

  Furthermore, triethoxyvinylsilane, which is a monomer having a hydrolyzable silyl group, glycidyl vinyl ether, glycidyl allyl ether, which are monomers having an epoxy group, aminopropyl vinyl ether, aminopropyl vinyl ether, which are monomers having amino groups, and the like Can also be mentioned.

  As a method for introducing a functional group by a reaction after polymerization, for example, a method in which a hydroxyl group is introduced by saponifying a polymer copolymerized with a carboxylic acid vinyl ester, a polyvalent carboxylic acid or its anhydride is added to a polymer having a hydroxyl group. To introduce a carboxy group by reacting a product, to introduce a hydrolyzable silyl group by reacting an isocyanate alkylalkoxysilane to a polymer having a hydroxyl group, to react a polyvalent isocyanate compound to a polymer having a hydroxyl group The method etc. which introduce | transduce an isocyanate group can be mentioned.

  Preferable specific examples of the fluoroolefin copolymer include, for example, a copolymer of chlorotrifluoroethylene and cyclohexyl vinyl ether, alkyl vinyl ether or hydroxyalkyl vinyl ether, and a copolymer of chlorotrifluoroethylene and alkyl vinyl ether or allyl alcohol. Mention may be made of a polymer, a copolymer of chlorotrifluoroethylene and an aliphatic carboxylic acid vinyl ester or hydroxyalkyl vinyl ether. In addition, the above copolymer can be formed using tetrafluoroethylene instead of chlorotrifluoroethylene. As these copolymers, those commercially available under trade names such as Lumiflon (Asahi Glass), Zeffle (Daikin Industries), Cefral Coat (Central Glass) can be used.

  A fluoroolefin type copolymer may be used individually by 1 type, and may be used in combination of 2 or more type. The number average molecular weight of the fluoroolefin copolymer is preferably 2,000 to 100,000, more preferably 6,000 to 30,000.

  In addition to the fluororesin, non-fluorine resin other than the fluoroolefin copolymer may be used alone or together with the fluoroolefin copolymer. Moreover, as resins other than fluororesins, alkyd resins, amino alkyd resins, polyester resins, epoxy resins, urethane resins, epoxy polyester resins, polyvinyl acetate resins, acrylic resins, vinyl chloride resins, phenol resins, silicone modified polyester resins, An acrylic silicone resin or a silicone resin may be used together with a fluororesin. Such a non-fluorine resin is used for the purpose of cost reduction, for example.

  Moreover, the content of the fluororesin in the second coating film of the first coating method and the coating film of the second coating method is 30 to 100% by mass% with respect to the total amount of the resin constituting these coating films. It is preferably 50% to 100%, more preferably 70% to 100%. By setting the content of the fluororesin within the above-described range, it becomes possible to sufficiently exhibit the weather resistance and the like that are unique to the fluororesin.

(Curing agent)
A hardening | curing agent is for hardening the fluororesin which is a main component which comprises a coating film. It is more preferable to include a curing agent in order to exhibit the solvent resistance, coating film hardness, etc. of the fluororesin.

  As the curing agent, various curing agents known as coating curing agents can be used. Specific examples of the curing agent include amino-based curing agents such as aminoplasts and urea resins, polyvalent isocyanate-based curing agents, and block polyvalent isocyanate-based curing agents. In the case of using a room temperature curing type curing agent, it is preferably blended before coating, and the blending time in the case of using a thermosetting type curing agent is not limited.

  A hardening | curing agent may be used individually by 1 type, and may be used in combination of 2 or more type. However, when a self-curing resin is used as the fluororesin, no curing agent may be used.

  The amount of the curing agent is selected according to the type, the type of the fluororesin, and the target curing rate, and includes the fluoroolefin copolymer having the above functional group as the fluororesin. In the case of using a product, the total number of moles of the curing group of the curing agent (hereinafter referred to as “number of moles of curing group”) and the total number of moles of the functional group of the fluoroolefin copolymer having a functional group (hereinafter referred to as “functional”). The ratio of (number of moles of group)) ((number of moles of cured group) / (number of moles of functional group), hereinafter, the value of the ratio is referred to as “total number of crosslinking points”) of 0.3 or more It is preferable to set it to 0.7 or more. By setting the total number of crosslinking points to 0.7 or more, the fluororesin is cured well and a coating film excellent in solvent resistance is obtained. The upper limit of the total number of crosslinking points is not particularly limited, but in consideration of the influence on the weather resistance and other performance due to the remaining reactive groups such as unreacted isocyanate groups in the coating film, 2.0 or less is Preferably, 1.3 or less is more preferable.

(Silicate compound)
The silicate compound has the effect of preventing the contamination of the surfaces of the second coating film of the first coating method and the coating film of the second coating method and maintaining the aesthetic appearance. This is because the hydrophilicity of the surface increases by forming moisture and Si-OH groups or Si-O-Si bonds in the air, and the attached dirt can be removed with water or the like. it is conceivable that.

The silicate compound is preferably represented by the following formula (1): Si (OR) ₄ ... (1)
(R represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, which may be the same as or different from each other.).

  When the carbon number of R in the formula (1) exceeds 5, the effect of maintaining the heat ray reflection performance tends to decrease, so the carbon number of R is 1-5. R is preferably an alkyl group having 1 or 2 carbon atoms because a particularly excellent heat ray reflection performance maintaining effect is obtained. Particularly preferred is tetramethoxysilane, tetraethoxysilane, or a partial condensate thereof.

The silicate compound preferably has a silica content of 20 to 60% by mass. If the silica content is too small, the low contamination is lowered, and if it is too much, the storage stability is impaired, which is not preferable. The silica content is the ratio of silica (SiO ₂ ) obtained when the compound is 100% hydrolyzed and condensed with respect to the silicate compound.

  The ratio of the silicate compound to the fluororesin is preferably 0.5 to 60% by mass, and more preferably 2 to 30% by mass. By making content of a silicate compound into the above-mentioned range, the effect which maintains a heat ray reflective performance improves, and generation | occurrence | production of a bubble, dripping, leveling, etc. can be suppressed and paintability can be improved.

  The silicate compound can be used in combination with a conventionally known acidic catalyst such as hydrochloric acid and p-toluenesulfonic acid or a metal chelate compound such as aluminum chelate as an accelerator.

(Silane coupling agent)
As a silane coupling agent contained in the first coating film of the first coating method and the coating film of the second coating method, for example, a silane compound represented by the general formula R ¹ SiR ² _3-a R ³ _a Can be mentioned. In the formula, R ¹ is at least one functional atom selected from a chlorine atom, amino group, aminoalkyl group, ureido group, glycidoxy group, epoxycyclohexyl group, acryloyloxy group, methacryloyloxy group, mercapto group and vinyl group. Or it is a C1-C10 alkyl group or vinyl group which has group.

  Examples of the alkyl group having such a functional substituent include β-aminoethyl group, γ-aminopropyl group, N- (β-aminoethyl) -γ-aminopropyl group, γ-ureidopropyl group, γ-glycol. Sidoxypropyl group, β- (3,4-epoxycyclohexyl) ethyl group, γ-acryloyloxypropyl group, γ-methacryloyloxypropyl group, γ-mercaptopropyl group, β-chloroethyl group, γ-chloropropyl group, γ -A vinylpropyl group etc. can be illustrated. Further, as the vinyl group having a functional substituent, an alkyl group having a functional substituent exemplified above in which an alkyl group at the terminal is replaced with a vinyl group can be used.

R ² and R ³ are each a chlorine atom, a hydroxyl group, an alkoxy group having 1 to 10 carbon atoms, an alkoxy-substituted alkoxy group having 2 to 15 carbon atoms, a hydroxyalkyloxy group having 2 to 4 carbon atoms, and an acyloxy having 2 to 15 carbon atoms. An atom or group selected from the group, a represents 0, 1 or 2;

  From the above, specific examples of the silane system preferably used include, for example, γ-aminopropyltriethoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, γ- Glycidoxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethylsilane, γ-methacryloxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, vinyltris (β -Methoxyethoxy) silane, vinyltriethoxysilane, vinyltrichlorosilane, vinyltriacetoxysilane, N- (trimethoxysilylpropyl) ethylenediamine, N-β-aminoethyl-γ-aminopropylmethyldimethoxysilane, β- Minoechiru -β- aminoethyl -γ- aminopropyltrimethoxysilane, and the like.

  The amount of the silane coupling agent contained in the first coating film of the first coating method is, for example, 0% by mass with respect to the total amount of the resin constituting the first coating film of the first coating method. 0.001 to 0.7% is preferable, 0.005 to 0.2% is more preferable, and 0.01 to 0.1% is particularly preferable.

  In addition, when forming the said 1st coating film using coating materials, such as a silane coupling agent containing coating material, it is preferable to dilute only a silane coupling agent with a solvent and to use as a coating material. In this case, it is preferable that the silane coupling agent is diluted with an alcohol such as ethanol, methanol, isopropyl alcohol or the like and applied as a paint. The amount of the silane coupling agent in the paint is 0.1% by mass based on the solid content. The content is preferably 01 to 10%, more preferably 0.05 to 1.0%, and particularly preferably 0.1 to 0.5%.

  Moreover, the amount of the silane coupling agent to be contained in the coating film of the second coating method is 0.001 to 0.00% in terms of mass% with respect to the total amount of the resin constituting the coating film for the same reason as described above. It is preferably 7%, more preferably 0.005 to 0.2%, and particularly preferably 0.01 to 0.1%. When the amount of the silane coupling agent is within the above range, the appearance of coating such as repelling and sagging is good, and the weather resistance and coating film hardness are improved.

(Acrylic silicone paint)
The acrylic silicone-based paint is a paint that can form a cured coating film of an acrylic resin crosslinked with —O—Si—O— bonds. As such an acrylic silicone paint, a polymerizable monomer having a hydrolyzable silyl group and an acrylic resin copolymerized with another polymerizable monomer and a reaction catalyst for the hydrolyzable silyl group are combined. Things can be used. A combination of an acrylic copolymer containing or not containing a hydrolyzable silyl group and a curing agent containing a hydrolyzable silyl group can also be used.

  As the solvent of the coating material, conventionally used solvents such as xylene, toluene, methyl isobutyl ketone, methyl ethyl ketone, butyl acetate and the like can be used.

  Moreover, additives, such as an antifoamer and a leveling agent, can be used for the said coating material.

  When an acrylic silicone paint is used as a paint for forming the first coating film of the first coating method, the first paint film is formed by applying the acrylic silicone paint to a substrate.

  When forming the 1st coating film of the 1st coating method, you may form by apply | coating this to a base material using the coating material which added the silane coupling agent to the acrylic silicone type coating material. In this case, the addition amount of the silane coupling agent is preferably 0.001 to 0.7% by mass% with respect to the total amount of the resin constituting the coating film, and is 0.005 to 0.2%. More preferably, it is particularly preferably 0.01 to 0.1%.

(UV absorber)
When it is desired to impart ultraviolet absorptivity to the second coating film of the first coating method and the coating film of the second coating method, an ultraviolet absorber can be contained in these coating films.

  As the ultraviolet absorber, for example, aromatic ester derivatives, benzophenone derivatives, cyanoacrylates, benzotriazole derivatives, hydroxyphenyltriazines, substituted acrylonitrile derivatives and the like can be used as necessary.

  Moreover, it is preferable that content of the ultraviolet absorber in a coating film is 0.1-20% by mass% with respect to the whole quantity of resin which comprises the said coating film, Furthermore, it is 0.5-10%. Preferably there is. By setting the amount of the ultraviolet absorber within the above range, the coating film can be prevented from being colored or softened, and the effect of absorbing ultraviolet rays can be improved.

(Matte material)
When it is desired to impart matting properties to the second coating film of the first coating method and the coating film of the second coating method, a matting agent can be contained in these coating films.

  In order to erase the gloss of the coating film, it is effective to make the surface of the coating film uneven, and for that purpose, a method of dispersing a particulate filler in the paint can be used. Accordingly, examples of the matting agent include particulate fillers, specifically, silica, alumina, barium sulfate, talc, and calcium carbonate resin bead particles. Among these, silica particles are preferable from the viewpoint of transparency and weather resistance.

  Further, the content of the matting agent in the coating film can be adjusted according to the desired gloss level within a range of 0.1 to 15% by mass with respect to the total amount of the resin constituting the coating film. . Preferably it is within 12%. By setting the matting agent within the above range, the matting degree of the coating film can be adjusted while maintaining the flexibility, chemical resistance, adhesion, weather resistance and the like of the coating film.

  In forming the first coating film and the second coating film, a room temperature drying method or a heat drying method can be used. The room temperature drying method is a method in which a predetermined coating material constituting a coating film is applied onto a substrate, and then allowed to dry at room temperature (room temperature) and cured to form a coating film. The heat drying method is a method in which a predetermined coating material constituting a coating film is applied on a substrate, and then left to dry at a temperature higher than room temperature, for example, about 80 ° C. to be cured to form a coating film.

  In addition, when apply | coating the said composition on a base material, it can apply | coat using methods, such as a spray, a roller, a brush, a roll coater, a gravure coater, a flow coater, a knife coater.

  In producing the coating material, the above-mentioned fluororesin can be obtained by dissolving it in a solvent such as xylene, toluene, MIBK, MEK, butyl acetate. Under the present circumstances, additives, such as an antifoamer and a leveling agent, can be contained as needed.

<Creation of paint>

Main agent-1 (second coating film of first coating method and coating main agent-1 constituting coating film of second coating method)
Fluororesin Lumiflon LF-200, a copolymer of chlorotrifluoroethylene, cyclohexyl vinyl ether, ethyl vinyl ether and hydroxyalkyl vinyl ether [manufactured by Asahi Glass Co., Ltd., hydroxyl group-containing fluoroolefin copolymer (hydroxyl value: 52 mgKOH / g) 60 mass% Organic solvent solution containing xylene] 30.0 g xylene, 3.0 g UV absorber (Viosorb 910, manufactured by Kyodo Yakuhin Co., Ltd.) were added to 60.0 g, and 0.0005 g dibutyltin dilaurate was added and stirred. It was.

Main agent-2 (second coating film of first coating method and main agent-2 of paint constituting coating film of second coating method)
The main agent 2 was prepared by adding 0.3 g of NUC silicone primer AP-133 (manufactured by Nihon Unicar), which is an aminosilane compound solution having a solid content of 5%, to the main agent-1 and stirring.

Main agent-3 (second coating film of first coating method and main agent-3 of paint constituting coating film of second coating method)
The main agent 3 was prepared by adding 4.0 g of silica-based matting agent Mizukasil P-526 (manufactured by Mizusawa Chemical) to the main agent-1 and stirring.

Curing agent-1
1.7 g of aluminum chelate D (manufactured by Kawaken Fine Chemicals Co., Ltd., aluminum chelate compound) is added to 31.0 g of Coronate HX (Nippon Polyurethane, non-yellowing type isocyanate curing agent) and mixed, and then MKC silicate MS56S [ Curing agent 1 was obtained by adding 17.0 g of a methyl silicate condensate made by Mitsubishi Chemical Co., Ltd. having a silica content of 56 mass% and adding 50.3 g of xylene.

Curing agent-2
Curing agent 2 was prepared by adding 28 g of xylene to 72 g of Coronate HX and mixing them.

Undercoat material-1 (main component of paint constituting the first coating film of the first coating method-1)
Undercoating material-1 was obtained by adding 30.0 g of isopropyl alcohol to 1.0 g of NUC silicone primer AP-133 (Nihon Unicar Co., Ltd.), which is an aminosilane compound solution having a solid content of 5%.

Undercoat material-2 (main component of paint constituting the first coating film of the first coating method-1)
TR sealer (AGC Co-Tech), which is an acrylic silicone clear paint, was used.

Undercoat material-3 (main component of paint constituting the first coating film of the first coating method-1)
Undercoating material-3 was obtained by adding 1 g of glycidoxypropyltrimethoxysilane Z-6040 (manufactured by Dow Corning Toray) to 99 g of xylene.

<Preparation of specimen>

Example 1
A glass plate was coated with 10 μm of the undercoat material-2 in a dry film thickness, allowed to stand at room temperature for 24 hours, and then a paint obtained by mixing the base agent-1 and the curing agent-1 at 5: 1 (parts by weight) was obtained in a dry film thickness. Was applied at 15 μm and allowed to stand at room temperature for 10 days to obtain a specimen A. The following evaluation test was performed on this specimen A.

[Appearance observation]
The appearance of the coating film of the prepared specimen was visually observed. When there was no abnormality, “no abnormality” was recorded, and when there was an abnormality, the phenomenon was recorded.
[Adhesion test]
According to JIS K 5600-5-6 adherence (cross-cut method), 6 incisions at intervals of 2 mm were made in each direction, and then a peel test was performed with a tape. According to JIS, the test results are shown in 6 levels, from “0” without any peeling to “5” separated by 65% or more area.
[Water resistance test]
The appearance change after immersing in 23 degreeC water for 30 days was observed. The adhesion test was also performed.
(Hot and cold repeated test)
The prepared specimen was immersed in 23 ° C. water for 18 hours according to the conditions of the hot and cold repeated test of JIS A 6909-7-10, then cooled in a −20 ° C. incubator for 3 hours, and then at a constant temperature of 50 ° C. The repetition condition of heating in the vessel for 3 hours was defined as one cycle, and after 30 cycles, appearance observation and adhesion test were performed.
[Boiling water resistance test]
After immersing the specimen in boiling water for 8 hours, an appearance observation and an adhesion test were performed.

(Example 2)
Instead of using the undercoat material-2 of the test body A, a test body was prepared in the same manner as the test body A except that 40 g of the undercoat material-3 was applied per 1 m ² , and the test was performed.

(Comparative Example 1)
A test body was prepared and tested in the same manner as in Example 1 except that the step of applying the primer 2 of Example 1 was omitted.

(Example 3)
A white glass was coated with 10 μm of the undercoat material-2 in a dry film thickness, dried at 80 ° C. for 1 hour, and then a paint obtained by mixing the main agent-1 and the curing agent-1 at 5: 1 (parts by weight) was obtained as a dry film thickness. Was applied at 15 μm and dried at 80 ° C. for 2 hours. The following test was performed on the obtained specimen B.

[Appearance observation]
The appearance of the coating film of the prepared specimen was visually observed. When there was no abnormality, “no abnormality” was recorded, and when there was an abnormality, the phenomenon was recorded.
[Adhesion test]
In accordance with JIS K 5600-5-6 adhesion (cross-cut method), 11 cuts with 1 mm intervals were placed in each direction, and a peel test was performed with a tape. The test results are shown in 6 stages, according to JIS, from “0” with no peeling at all and “5” separated by an area of 65% or more.
[Boiling water resistance test]
After immersing the test body in boiling water for 12 hours, appearance observation and adhesion test were performed.
(Contact angle measurement)
Using a FACE contact angle meter CA-A type (manufactured by Kyowa Interface Chemical Co., Ltd.), ion-exchanged water and liquid paraffin (manufactured by Kanto Chemical Co., Ltd., deer grade 1, specific gravity 15/15 ° C. 0.870 to 0.890) The droplets were adjusted to 0.005 ml each and the contact angle was measured.
[Exposure test]
The specimen B was tilted 30 degrees from the horizon in the city of Matsudo, Chiba, and exposed to the south surface for 1 year. The state of contamination was visually observed, x if markedly contaminated, and ○ if almost not contaminated. The middle was recorded as Δ.

Example 4
A coating material in which main agent-2 and curing agent-1 were mixed at a ratio of 5: 1 (parts by weight) to white glass was applied at a dry film thickness of 15 μm and dried at 80 ° C. for 2 hours. The same test as in Example 3 was performed on the obtained specimen C.

(Example 5)
A test body was prepared and tested in the same manner as in Example 3 except that the main agent-1 of Example 3 was used instead of the main agent-3.

(Example 6)
A test specimen was prepared and tested in the same manner as in Example 3 except that the primer 1 was applied instead of the primer 3 of Example 3 and dried at room temperature for 20 minutes. .

(Comparative Example 2)
A test body was prepared and tested in the same manner as in Example 3 except that the step of applying primer 3 of Example 3 and drying by heating was omitted.

(Comparative Example 3)
Instead of preparing the main agent 1 and the curing agent 1 of Example 3 at 5: 1 (weight ratio), the same as the example 3 except that the main agent 1 and the curing agent 2 were mixed at 15: 1 (weight ratio). Went in the way.

  As can be seen from Tables 1 and 2, it was found that in the examples according to the present invention, the above-described appearance observation results were also good and the coating film adhesion was excellent. It was also found that the appearance was good and the adhesion of the coating film was excellent after the water resistance test and the boiling water resistance test. Further, in the exposure test, almost no contamination was observed, the contact angle was excellent, and it was found to have a relatively high hydrophilicity. That is, it can be seen that the degree of contamination of the specimen depends to some extent on the hydrophilicity of the specimen.

  While the present invention has been described in detail based on the above specific examples, the present invention is not limited to the above specific examples, and various modifications and changes can be made without departing from the scope of the present invention.

Claims (12)

A method for coating a substrate, comprising:
Forming a first coating film composed of at least one of an acrylic silicone paint and a silane coupling agent-containing paint on a substrate;
Forming a second coating film comprising a second coating material containing a fluororesin, a curing agent, and a silicate compound on the first coating film;
A method for coating a substrate, comprising: The silicate compound contained in the second paint is a compound represented by the following formula (1) or a partial condensate of the compound represented by the formula (1). Substrate coating method Si (OR) ₄ .... (1)
(R represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, which may be the same as or different from each other.).   The substrate coating method according to claim 1 or 2, wherein the second paint contains a non-fluorine resin.   The said 2nd coating material contains at least one of a ultraviolet absorber and a matting agent, The coating method of the base material as described in any one of Claims 1-3 characterized by the above-mentioned.   5. The substrate coating method according to claim 1, wherein at least one of the first coating film and the second coating film is formed by a room temperature drying method. 6.   5. The substrate coating method according to claim 1, wherein at least one of the first coating film and the second coating film is formed by a heat drying method. 6. A method for coating a substrate, comprising:
A method for coating a base material, comprising a step of forming a coating film comprising a paint containing a fluororesin, a curing agent, a silicate compound, and a silane coupling agent on the base material. The silicate compound contained in the paint is a compound represented by the following formula (2) or a partial condensate of the compound represented by the formula (2). Coating method Si (OR) ₄ ... (2)
(R represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, which may be the same as or different from each other.).   The base material coating method according to claim 7 or 8, wherein the paint contains a non-fluorine resin.   The said coating material contains at least one of an ultraviolet absorber and a matting agent, The coating method of the base material as described in any one of Claims 7-9 characterized by the above-mentioned.   The substrate coating method according to any one of claims 7 to 9, wherein the coating film is formed by a room temperature drying method.   The substrate coating method according to any one of claims 7 to 9, wherein the coating film is formed by a heat drying method.