JP2002273340A - Method for forming coating film and car body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming a coating film having a high hydrophilizing speed, developing stain resistance even before a rainfall, excellent in the stain resistance of a polished surface part and keeping stain resistance over a long period of time, and a car body using the method. SOLUTION: In the method for forming the coating film including a process for applying a hydrophylizing treatment agent to a base material having a coating film surface hydrophilic or capable of being made hydrophilic and drying the coated base material, the hydrophilizing treatment agent contains a hydrolysate of a silicate compound represented by formula (1) (wherein, (n) is an integer of 1-30, and groups R<1> may be different and are 1-8C alkyl groups which have each a substituent or have no substituent), a nonionic surfactant, water and a hydrophilic organic solvent, and the nonionic surfactant has an alkylene oxide unit and HLB thereof is 10-15 and the amount thereof to water is 0.02-10 mass %.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a coating film using a hydrophilizing agent, and more particularly, to a method for applying a hydrophilizing agent on a substrate having a hydrophilic or hydrophilizable coating surface. The present invention relates to a coating film forming method including a drying step, and an automobile body having a coating film formed by the above coating film forming method.

[0002]

2. Description of the Related Art Topcoat paints for automobiles have the minimum performance as a paint and have the storage stability, and because they constitute the outermost layer of the paint film for painting the body of automobiles, they have aesthetic and cosmetic properties.
It is required to have weather resistance and the like as basic performance. Further, it has been required to easily remove dirt when contaminants such as soot and dust adhere to the coating film, that is, stain resistance.

[0003] Japanese Patent Application Laid-Open No. Hei 10-140077 discloses that an acid epoxy-curable paint is coated with tetramethyl silicate and / or
Also disclosed is an automotive topcoat containing a low-condensate of silicate having a degree of condensation of 2 to 10 (low-condensate of silicate). The purpose of this paint is to solve the above-mentioned problem concerning stain resistance. In this technique, a low condensate of tetramethyl silicate and / or tetraethyl silicate is used to reduce the number of carbon atoms of the alkoxyl group and maintain reactivity with water. And the coating film of this coating composition, the methoxy group or ethoxy group of the silicate low-condensate, which is often present in the vicinity of the coating film surface, reacts with water by exposure or treatment with an acid to form a hydroxyl group. The basic principle is to exhibit high hydrophilicity due to hydroxyl groups and to exhibit contamination resistance.

[0004] However, the coating film obtained here requires one month or more to be hydrolyzed and converted into a hydrophilic coating film surface if it does not rain, and it takes one to two weeks even in the case of heavy rainfall. Was. Until the surface becomes hydrophilic, once a hydrophobic contaminant adheres, there is a problem that it is difficult to remove dirt only by rainfall.

[0005] In addition, in the automobile coating line, if dust, spots, scratches, etc. are found on the painted surface after the top coating,
After removing the dust and lumps, # 2400, # 400
There is a process of polishing and finishing with 0 sandpaper.

In the polished portion of the above-mentioned coating film, the silicate-containing layer which is often present in the vicinity of the coating film surface is shaved off, so that the hydrophilicity is lost and the stain resistance is reduced. Therefore, when looking at the entire automobile coating film, depending on the presence or absence of polished parts, there are parts with different levels of hydrophilicity, and there is a significant difference in the stain resistance level, so that when exposed, black and white mottled patterns occur There is.

[0007] Japanese Patent Application Laid-Open No. 2000-256619 discloses that
A stain-proofing method for an overcoat film in which a silicon compound or a hydrolyzed condensate thereof (a), or a mixture of (a) and a catalyst and / or an organic solvent capable of hydrolyzing the silicon compound is applied to the overcoat film. It has been disclosed. However, the hydrophilic coating film formed on the surface by the stain-resistant treatment method gradually dissolves and disappears due to rainfall, so that there is a problem that the effect of the hydrophilic coating film is lost in several months.

Further, WO 95/17349 discloses a hard coat composition obtained by mixing tetramethoxysilane with water. This composition can form a film by the impregnation method, but has a problem that the film is broken by the spray method. There is no description about the purpose of making the surface hydrophilic with this composition.

[0009]

SUMMARY OF THE INVENTION In view of the above-mentioned situation, the present invention has a high hydrophilization rate, exhibits stain resistance even before rainfall, and has a low stain resistance of a polished surface. It is an object of the present invention to provide a method for forming a coating film in which stain resistance is maintained for a long time, and an automobile body using the same.

[0010]

Means for Solving the Problems The present inventors apply a hydrophilizing treatment agent containing a specific silicate compound to a substrate having a hydrophilic or hydrophilizable coating film surface, thereby reducing rainfall. Even under the situation where the coating film on the base material is not sufficiently hydrophilic as in the previous case, the stain resistance is exhibited by the hydrophilizing agent applied to impart hydrophilicity applied thereon, and Since the surface of the polished surface is also coated with a hydrophilizing agent, the polished portion is also excellent in stain resistance. Dissolves and disappears one by one, but the hydrophilicity or the hydrophilizable coating film previously formed on the base material is sufficiently hydrophilic, so that the hydrophilicity can be maintained continuously. Demonstrate excellent contamination resistance from the beginning It found, and completed the present invention.

That is, the present invention relates to a method for forming a coating film comprising a step of applying a hydrophilizing agent on a substrate having a hydrophilic or hydrophilizable coating film surface, followed by drying. The treating agent contains a hydrolyzate of a silicate compound represented by the following formula (1), a nonionic surfactant, water and a hydrophilic organic solvent, and the nonionic surfactant has an alkylene oxide unit. And the HLB thereof is 10 to 15, and the amount based on the water is 0.02 to 1
0% by mass.

[0012]

Embedded image

(Wherein, n represents an integer of 1 to 30; R
¹ may represent a different one, and represents a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms.) The content of the hydrolyzate of the silicate compound is
It is preferable that the content is 0.05 to 10% by mass in the hydrophilizing agent.

[0014] The base material having a hydrophilic or hydrophilizable coating film surface is a base material obtained by applying a topcoat paint, and the topcoat paint comprises a base paint and a clear paint. When the application of the top coating is to apply the base coating and the clear coating in this order, the clear coating is a silicate compound (i) represented by the following formula (2) and / or It is preferable that it contains resin (ii) obtained by grafting a silicate compound represented by the formula (2).

[0015]

Embedded image

(Wherein m represents an integer of 1 to 30; R
² may represent different ones, a hydrogen atom, or a substituted or unsubstituted carbon atom having 1 to 2 carbon atoms.
The clear paint contains a resin (ii) obtained by grafting a silicate compound represented by the formula (2), and comprises a half ester acid group-containing acrylic copolymer (I). And an epoxy group-containing acrylic copolymer (II).

The substrate having a hydrophilic or hydrophilizable coating film surface is a substrate obtained by applying a topcoat to a substrate, wherein the topcoat is a solid color paint. Means that the solid color paint is a silicate compound (i) represented by the following formula (2), and / or
Alternatively, it is preferable that the resin (b) contains a resin (ii) obtained by grafting a silicate compound represented by the following formula (2).

[0018]

Embedded image

(Wherein m represents an integer of 1 to 30; R
² may represent different ones, a hydrogen atom, or a substituted or unsubstituted carbon atom having 1 to 2 carbon atoms.
The solid color paint contains resin (ii) obtained by grafting a silicate compound represented by the formula (2), and preferably further contains a curing agent. The hydrophilic treatment agent has a dry film thickness of 0.01 to 10 μm
It is preferably applied to the surface. The present invention is also an automobile body having a coating film formed by the above-described coating film forming method. Hereinafter, the present invention will be described in detail.

The method for forming a coating film of the present invention is characterized in that
Apply a hydrophilizing agent on a substrate having a coatable surface.
Cloth and drying steps are included.Hydrophilizing agent  The hydrophilizing agent is a hydrolyzate of a silicate compound,
Including nonionic surfactant, water and hydrophilic organic solvent
I have. The hydrolyzate of the silicate compound is represented by the above formula
Hydrolyzing the silicate compound represented by (1)
It is something that can be done.

In the above formula (1), n represents an integer of 1 to 30. If it exceeds 30, the particle properties of the silicate compound become high, and the appearance of the coating film becomes poor, such as cloudiness. From the viewpoint of making the hydrolyzate of the silicate compound an appropriate viscosity, 1 to 25 is preferable, and 5 to 25 is more preferable.

In the above formula (1), R ¹ may be different, and represents a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms. If the number of carbon atoms exceeds 8, the hydrolyzability decreases, which is not preferable. An alkyl group having 1 to 4 carbon atoms is more preferable, and an alkyl group having 1 or 2 carbon atoms is particularly preferable. Most preferred is a methyl group.

Examples of the above-mentioned alkyl group having 1 to 8 carbon atoms which has a substituent or no substituent include a methyl group, an ethyl group, a propyl group, an isopropyl group and an n-
Butyl group, sec-butyl group, tert-butyl group, n
Straight-chain or branched ones such as an amyl group, an isoamyl group, a neoamyl group, a hexyl group, a heptyl group, an octyl group and a 2-ethylhexyl group. Among these, a methyl group, an ethyl group, a propyl group, an isopropyl group, and an n-butyl group are preferred. More preferred are a methyl group and an ethyl group, and particularly preferred is a methyl group. The substituent for the alkyl group is not limited, and examples thereof include halogen such as chloro and bromo; alkoxy groups such as methoxy and ethoxy; cyano groups and dimethylamino groups. Even in the case of having the above substituent, the alkyl group preferably has 1 to 8 carbon atoms.

Specific examples of the silicate compound in which R ¹ is a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms include tetramethoxysilane, tetraethoxysilane and tetra-n-propoxysilane. ,
Tetra-iso-propoxysilane, tetra-n-butoxysilane, tetra-sec-butoxysilane, tetra-tert-butoxysilane, tetra-n-pentoxysilane, tetra-iso-pentoxysilane, tetraneopentoxysilane, etc. A single or two or more condensates thereof; Preferably, it is methyl silicate and / or its condensate, or ethyl silicate and / or its condensate, and most preferably is the condensate of methyl silicate.

As the condensate of the above-mentioned methyl silicate,
For example, commercially available products such as “MKC silicate MS51”, “MKC silicate MS56”, and “MKC silicate MS60” (all of which are trade names, manufactured by Mitsubishi Chemical Corporation) are exemplified. As the condensate of the ethyl silicate, for example,
"Ethyl silicate 28", "Ethyl silicate 4
And commercially available products such as "0" and "ethyl silicate 48" (both are trade names, manufactured by Colcoat).

The above-mentioned hydrolysis can be obtained by reacting the above-mentioned silicate compound with water having an equivalent or more of the alkoxysilyl group of the above-mentioned silicate compound. The reaction proceeds at room temperature, but can be heated if necessary. Preferably, a hydrolyzate of the silicate compound can be obtained by adding the silicate compound to a large excess amount of water in the presence of a catalyst and leaving it to stand. As the catalyst, those generally used in a hydrolysis reaction can be used. For example, inorganic acids such as hydrochloric acid, acetic acid, nitric acid, formic acid, sulfuric acid, and phosphoric acid; formic acid, acetic acid, propionic acid,
Organic acids such as oxalic acid, paratoluenesulfonic acid, benzoic acid, phthalic acid and maleic acid; alkaline catalysts such as potassium hydroxide, sodium hydroxide, calcium hydroxide and ammonia; organic metals; metal alkoxides such as dibutyltin dilaurate , Organic tin compounds such as dibutyltin dioctate, dibutyltin diacetate, aluminum tris (acetylacetonate), titanium tetrakis (acetylacetonate), titanium bis (butoxy) bis (acetylacetonate), titanium bis (isopropoxy) bis (Acetylacetonate),
Metal chelate compounds such as zirconium tetrakis (acetylacetonate), zirconium bis (butoxy) bis (acetylacetonate) and zirconium bis (isopropoxy) bis (acetylacetonate), and boron compounds such as boron butoxide and boric acid. be able to. The amount of the catalyst is not particularly limited, but can be usually 0.1 to 5% by mass based on the silicate compound.

Further, since the silicate compound has insufficient solubility in water, it is preferable to add a hydrophilic organic solvent to homogenize the system so that the hydrolysis reaction proceeds efficiently. As such a hydrophilic organic solvent, those which are freely miscible with water are preferable, for example, alcohols such as methanol, ethanol and isopropyl alcohol; and glycol derivatives such as ethylene glycol and ethylene glycol monomethyl ether;
Ethylene glycol monoethyl ether, ethylene glycol mono n-propyl ether, ethylene glycol mono n-butyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether and the like; ketones such as acetone and methyl ethyl ketone Ethers such as dioxane and tetrahydrofuran can be used. The amount of the hydrophilic organic solvent to be added is not particularly limited as long as the silicate compound is dissolved or more.

By measuring the IR spectrum of the hydrolyzate, it can be confirmed that the peak based on the alkoxysilyl group has disappeared. That is,
It is considered that the hydrolyzate of the silicate compound has a structure in which the alkoxysilyl group in the above formula (1) is hydrolyzed to a silanol group. It is considered that the presence of the silanol group causes the hydrophilicity to be exhibited immediately after the application. However, the above hydrolyzate does not have to have all alkoxysilyl groups hydrolyzed to silanol groups. Typically, a homogeneous system containing the catalyst requires 12
The desired hydrolyzate can be obtained by leaving it for more than an hour. The hydrolyzate thus obtained is
At the time of isolation, the condensation reaction between the hydrolysates may proceed, so it is preferable to use the solution obtained by performing the hydrolysis as it is.

The content of the hydrolyzate of the silicate compound in the hydrophilizing agent is preferably an amount corresponding to 0.05 to 10% by mass of the silicate compound before the hydrolysis. When the content is less than 0.05% by mass, sufficient hydrophilicity cannot be imparted, and when the content exceeds 10% by mass, the appearance of the obtained film may be deteriorated. More preferably,
It is 0.1 to 5% by mass, particularly preferably 0.1 to 3% by mass.

The nonionic surfactant contained in the hydrophilizing agent lowers the surface tension of water, thereby enabling uniform application of the hydrophilizing agent regardless of the application means. On the other hand, in the case of a cationic surfactant or an anionic surfactant, the stability of the hydrophilizing agent may be reduced or uniform application may not be achieved.

As the nonionic surfactant, those having an alkylene oxide unit as a hydrophilic group are used. As such a material, a polyalkylene glycol monoalkyl ether is preferable. HLB which is an index of the balance between hydrophilicity and hydrophobicity of the nonionic surfactant is 10 to 15. Outside these ranges, uniform application may not be possible. The HLB is a value obtained by dividing the molecular weight of the entire nonionic surfactant by the molecular weight of the alkylene oxide unit.
This is a value obtained by multiplying by zero.

Examples of the kind of the alkylene oxide unit include ethylene oxide, propylene oxide, and tetramethylene oxide. Among them, ethylene oxide and propylene oxide are preferable. Further, the number of repetitions of the alkylene oxide unit is preferably 7 to 10. The alkyl group of the alkyl ether preferably has 12 to 18 carbon atoms.

The content of the nonionic surfactant in the hydrophilizing agent is 0.02 to 10% by mass based on the water contained in the hydrophilizing agent. If the amount is less than 0.02% by mass, the hydrophilic treatment agent cannot be applied uniformly, and if the amount exceeds 10% by mass, no improvement in the effect is observed, and the coating film performance may be poor. More preferably, 0.1 to 5
% By weight.

The hydrophilizing agent contains water and a hydrophilic organic solvent as solvents. As the hydrophilic organic solvent, those mentioned above can be used, but methanol, ethanol, and isopropyl alcohol are particularly preferable in consideration of volatility and solubility. The mass ratio of water to the hydrophilic organic solvent is not particularly limited, but is, for example, 5/95 to 95/95.
5 can be set.

The above-mentioned hydrophilizing agent can be obtained by mixing the above-mentioned components, and a solution obtained by hydrolyzing the above-mentioned silicate compound or a solution before hydrolyzing a predetermined amount of nonionic It can also be obtained by a method of adding a system surfactant. In these cases, it is preferable to mix each component so as to have a predetermined concentration.However, for a solution obtained by performing hydrolysis of the silicate compound,
The dilution can be adjusted to a predetermined concentration by diluting with water and / or a hydrophilic organic solvent. The hydrophilizing agent obtained by this method contains the above-mentioned catalyst used for hydrolysis.

The method for applying the above-mentioned hydrophilizing agent is not particularly limited, and examples thereof include spray coating, roll coating, brush coating, dip coating, and wipe coating. As a drying method after the above-mentioned coating, the coating may be left at room temperature until it is dried.
It may be performed by heating for about a minute. The dry film thickness of the hydrophilizing agent is preferably from 0.01 to 10 μm. If it is less than 0.01 μm, stain resistance may not be obtained for a long period of time, and if it exceeds 10 μm, the transparency of the coating film may be inferior or cracks may occur. More preferably, it is 0.01 to 5 μm.

[0037]Has a hydrophilic or hydrophilizable coating surface
Base material  In the present invention, the hydrophilic treatment agent is hydrophilic or hydrophilic.
To be applied to a substrate having a coatable film surface.
You. With the substrate having the hydrophilic coating film surface, the water contact angle
Means a substrate having a coating film surface of not more than 50 °
And a substrate having a coating surface that can be hydrophilized is defined as J
6 months outdoor exposure according to IS K 5400 9.9
When a dew test is performed, the water contact angle is 50 ° or less.
It means a substrate having a film surface. Coating surface
If the water contact angle is 50 ° or less, if it exceeds 50 °
By comparison, it is much less contaminated and
Pollution resistance, such as easy removal of pollution only by water or rain
Excellent in nature. Preferably, the water contact angle is 35 ° or less
Is the case.

The above-mentioned substrate having a hydrophilic or hydrophilizable coating film surface is usually one in which a top coat is applied to the outermost surface of the substrate to form a top coat. The overcoat is not particularly limited, and includes, for example, a base paint and a clear paint, and the application of the overcoat is performed by applying the base paint and the clear paint in this order, and a solid color paint. Things can be mentioned.

When the above base paint and clear paint are used, the clear paint is an acid / epoxy curable clear paint containing a half ester acid group-containing acrylic copolymer (I) and an epoxy group-containing acrylic copolymer (II). It is preferred that On the other hand, when the solid color paint is used, it is preferable that the paint contains a curing agent such as a melamine-based curing agent.

[0040]For acid / epoxy curable clear paint  The above acid / epoxy curable clear coating is a half-ester
Acrylic acid group-containing acrylic copolymer (I) and epoxy group-containing
Acrylic copolymer (II) as a resin component
You.

The half-ester acid group-containing acrylic copolymer (I) comprises an acid anhydride group-containing radical polymerizable monomer (Ia) and another radical polymerizable monomer (Ib).
And a half-esterification of the acid anhydride group with a low molecular weight alcohol-based compound after obtaining a copolymer.

As the acid anhydride group-containing radical polymerizable monomer (Ia), an acid anhydride group-containing radical polymerizable monomer for obtaining the half ester acid group-containing acrylic copolymer (I) can be used. It is not particularly limited as long as it is a suitable monomer, and examples thereof include itaconic anhydride, maleic anhydride, and citraconic anhydride. These may be used alone,
More than one species may be used in combination.

The other radical polymerizable monomers (I-
There is no particular limitation on b), and examples thereof include a hydroxyl group-containing radically polymerizable monomer. The hydroxyl group-containing radical polymerizable monomer is not particularly limited, and examples thereof include 2-hydroxyethyl (meth) acrylate and 2-hydroxyethyl (meth) acrylate.
Hydroxyalkyl (meth) acrylates such as hydroxypropyl (meth) acrylate and 4-hydroxybutyl methacrylate; Praxel FM-1 (trade name, 2
Adduct of hydroxyethyl (meth) acrylate and polycaprolactone, manufactured by Daicel Chemical Industries, Ltd.); polyalkylene glycol mono (meth) acrylates, and the like. These may be used alone or in combination of two or more.

The other monomers are not particularly limited, and include, for example, styrenes such as styrene and α-methylstyrene, and aromatic vinyl monomers such as vinyl toluene; methyl acrylate, ethyl acrylate, and the like. Propyl acrylate, n-, i- or t-butyl acrylate, acrylic acid-
Acrylates such as 2-ethylhexyl and lauryl acrylate; methacryl such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, -n, i or t-butyl methacrylate, 2-ethylhexyl methacrylate and lauryl methacrylate Acid esters; acrylamide monomers such as acrylamide, methacrylamide, N-ethyl (meth) acrylamide, N, N-butoxymethyl (meth) acrylamide, N-methylacrylamide; dimethylaminoethyl (meth) acrylate, diethylamino Amino group-containing monomers such as ethyl (meth) acrylate; acrylonitrile, vinyl acetate,
Examples include acrylic acid and methacrylic acid. These may be used alone or in combination of two or more.

The above acid anhydride group-containing radical polymerizable monomer (Ia) and the other radical polymerizable monomer (I-
b) in the copolymer composition when obtaining a copolymer by
The above acid anhydride group-containing radical polymerizable monomer (Ia)
Is 10 to 40% by mass, especially 15% by mass, based on the total monomer mass.
-30% by mass is preferred.

The above copolymerization method is not particularly limited.
It can be obtained by copolymerizing the above-mentioned monomer components with a radical polymerization initiator. The copolymerization method is not particularly limited, and the copolymerization can be carried out by a usual solution polymerization such as radical polymerization.

The radical polymerization initiator is not particularly restricted but includes, for example, t-butylperoxy-2-ethylhexanoate, dimethyl-2,2'-azobisisobutyrate and the like. These may be used alone,
Two or more kinds may be used in combination. The radical polymerization initiator is preferably used in an amount of 3 to 15% by mass based on the total amount of the above-mentioned monomers. A chain transfer agent or the like may be added as an additive to the copolymerization.

The number average molecular weight (Mn) of the above copolymer is
500 to 10,000, particularly preferably 1,000 to 8,000, is preferred. When the number average molecular weight (Mn) is less than 500,
If the curability of the paint is not sufficient, and if it exceeds 10,000, the viscosity of the copolymer will increase, and a large amount of organic solvent will be used at the time of painting, which may adversely affect the environment.

The acid anhydride group in the copolymer is
It contains at least two in one molecule. If the number is less than 2, the curability is insufficient. Preferably 2
There are fifteen.

The above half esterification is performed after obtaining the above copolymer. The half-esterifying agent used for half-esterifying the acid anhydride group is not particularly limited as long as it is a low-molecular-weight alcohol compound. For example, methanol, ethanol, n-propanol, i-
Propanol, n-butanol, i-butanol, t-
Butanol, methyl cellosolve, ethyl cellosolve, dimethylaminoethanol, diethylaminoethanol,
Acetol, allyl alcohol, propargyl alcohol and the like can be mentioned. These may be used alone or in combination of two or more. Among these, particularly preferred compounds are acetol, allyl alcohol, propargyl alcohol and methanol. The low molecular weight alcohol compound used as the half-esterifying agent may contain another hetero atom such as an N atom or an S atom, or a carbon-carbon unsaturated bond.

The reaction method for the half esterification is not particularly limited. For example, the half esterification can be carried out according to a usual method at a temperature from room temperature to 120 ° C. in the presence of a catalyst.
The catalyst is not particularly limited, and includes, for example, tertiary amines such as triethylamine and tributylamine; and quaternary ammonium salts such as benzyltrimethylammonium chloride, benzyltrimethylammonium bromide, benzyltributylammonium chloride, and benzyltributylammonium bromide. Is mentioned. These may be used alone or in combination of two or more.

The epoxy group-containing acrylic copolymer (I)
I) is an epoxy group-containing radically polymerizable monomer (II-a) 30 to 70 with the total of all monomers being 100 parts by mass.
Mass part, hydroxyl group-containing radical polymerizable monomer (II-b)
It is a copolymer obtained by copolymerizing 10 to 50 parts by mass and 20 to 60 parts by mass of another radical polymerizable monomer (II-c).

The epoxy group-containing radical polymerizable monomer (II-a) is not particularly restricted but includes, for example, epoxy group-containing acryl such as glycidyl (meth) acrylate and 3,4-epoxycyclohexanylmethyl methacrylate. Monomers. These may be used alone or in combination of two or more.

The hydroxyl-containing radical polymerizable monomer (I)
Ib) and other radically polymerizable monomers (II-
Examples of c) include those exemplified above, and the polymerization can be carried out in the same manner as in the above method.

The epoxy group-containing acrylic copolymer (I)
I) has a number average molecular weight (Mn) of 1,000 to 8,000, has 2 to 10 epoxy groups in the molecule, and 2 to 12 hydroxyl groups, and has an epoxy equivalent of 100 to 8,000.
800 and a hydroxyl value of 5 to 200 mgKOH / g. When the epoxy equivalent is less than 100, the cured coating film becomes too hard and the weather resistance is deteriorated. When it exceeds 800, the curability of the coating becomes insufficient. The hydroxyl value is 5
When the amount is less than mgKOH / g, the adhesion is poor and the
If it exceeds gKOH / g, the cured coating film has insufficient water resistance. Preferably, it has 3 to 8 epoxy groups and 4 to 10 hydroxyl groups in the molecule, and has an epoxy equivalent of 200 to 600 and a hydroxyl value of 10 to 150 m.
gKOH / g.

The acid / epoxy curable clear coating used in the present invention preferably further comprises a carboxyl group-containing polyester resin (III) as a resin component. The carboxyl group-containing polyester resin (II
I) is obtained by half-esterifying a polyester polyol obtained by adding a lactone compound to a low molecular weight polyhydric alcohol and performing a chain extension reaction with an acid anhydride group-containing compound.

The carboxyl group-containing polyester resin (III) has a sharp molecular weight distribution.
By using the carboxyl group-containing polyester resin (III) as a resin component, high solid differentiation (high solidification) of the clear paint used in the present invention becomes possible,
A coating film having excellent weather resistance and water resistance can be obtained, and at the same time, a coating film having excellent chipping resistance and skin appearance can be obtained.

The low-molecular-weight polyhydric alcohol is not particularly limited. For example, alcohols having at least three hydroxyl groups in one molecule and having a molecular weight of 300 or less are preferable, and trimethylolpropane, trimethylolethane, Examples thereof include 1,2,4-butanetriol, ditrimethylolpropane, pentaerythritol, dipentaerythritol, and glycerin. These may be used alone or in combination of two or more.

The lactone compound may be any cyclic compound which has an oxygen atom in the ring, reacts with a nucleophile, opens the ring, and generates a hydroxyl group at the terminal. Since the ring-opening addition reaction easily occurs, the lactone compound has 4 to 7 carbon atoms.
Are preferred.

The lactone compound is not particularly restricted but includes, for example, ε-caprolactone, γ-caprolactone, γ-valerolactone, δ-valerolactone, γ-butyrolactone and the like. These may be used alone or in combination of two or more. Among these, ε
-Caprolactone, γ-valerolactone and γ-butyrolactone are preferred.

The above chain elongation reaction can be carried out under the same conditions as in a usual ring opening addition reaction. For example, the polyester polyol in which the low-molecular-weight polyhydric alcohol is chain-extended can be obtained by reacting in a suitable solvent or without a solvent at a temperature of 80 to 200 ° C. within 5 hours. At this time, a tin-based catalyst or the like may be used.

In the above chain extension reaction, the molar amount of the lactone compound is 0.2 to 10 times the molar amount of the hydroxyl group of the low molecular weight polyhydric alcohol. When the molar amount of the lactone compound is less than 0.2 times the molar amount of the hydroxyl group of the low molecular weight polyhydric alcohol, the coating film becomes hard and the impact resistance of the coating film decreases, and exceeds 10 times the molar amount. In this case, the hardness of the coating film decreases. The amount is preferably 0.25 to 5 times, more preferably 0.3 to 3 times.

The method of half-esterification of the polyester polyol with the acid anhydride group-containing compound is not particularly limited. For example, the polyester polyol and the acid anhydride group-containing compound are reacted according to a conventional method. It can be carried out at a temperature from room temperature to 150 ° C. under normal pressure.

The above-mentioned compound containing an acid anhydride group is not particularly restricted but includes, for example, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, 4-methylhexahydrophthalic anhydride, trimellitic anhydride, succinic anhydride. And the like. These may be used alone or in combination of two or more.

In general, the molar amount of the acid anhydride group of the acid anhydride group-containing compound is 0.2 to 1.0 times, especially 0.5 to 1.0 times the molar amount of the hydroxyl group of the polyester polyol.
Preferably, the amount is 0.9 times. If the molar amount of the acid anhydride group of the acid anhydride group-containing compound is less than 0.2 times the molar amount of the hydroxyl group of the polyester polyol, the curability of the coating will be insufficient.

However, it is not necessary to modify all the hydroxyl groups of the polyester polyol to carboxyl groups, and the hydroxyl groups may be left. That is, since the carboxyl group-containing polyester resin (III) having a hydroxyl group simultaneously provides a carboxyl group and a hydroxyl group on the surface of the coating film, for example, when recoated, the carboxyl group-containing polyester resin having no hydroxyl group is used. Excellent adhesion can be provided as compared with (III).

The carboxyl group-containing polyester resin (III) has an acid value of 50 to 350 mgKOH / g, a number average molecular weight (Mn) of 400 to 3,500,
Weight average molecular weight (Mw) / number average molecular weight (Mn) is 1.
8 or less. If the acid value is less than 50, the curability of the coating will be insufficient, and if the acid value exceeds 350, the viscosity of the carboxyl group-containing polyester resin (III) will be too high, and a large amount of an organic solvent will be used during coating. Therefore, there is a risk of adversely affecting the environment. When the molecular weight is less than 400, the curability of the coating material is insufficient or the water resistance of the coating film is reduced. When the molecular weight exceeds 3,500, the viscosity of the carboxyl group-containing polyester resin (III) becomes too high to handle. In this case, a large amount of organic solvent is used at the time of coating, which may adversely affect the environment. Weight average molecular weight (Mw) / number average molecular weight (Mn) is 1.8
If it exceeds 2,000, the water resistance or weather resistance of the coating film will decrease.

Preferably, the acid value is 100 to 300 mgK
OH / g and a number average molecular weight (Mn) of 500 to 25
00, and the weight average molecular weight (Mw) / number average molecular weight (Mn) is 1.5 or less. More preferably, the acid value is 150 to 250 mgKOH / g, the number average molecular weight (Mn) is 700 to 2000, and the weight average molecular weight (Mw) / number average molecular weight (Mn) is 1.35 or less.

When the carboxyl group-containing polyester resin (III) has a hydroxyl group, the carboxyl group-containing polyester resin (III) has a hydroxyl value of 150 mgKOH / g or less. Hydroxyl value is 15
If it exceeds 0 mgKOH / g, the water resistance of the coating film decreases. Preferably, it is 5 to 100 mgKOH / g, more preferably 10 to 80 mgKOH / g.

The carboxyl group-containing polyester resin (III) having a hydroxyl group and a carboxyl group
Can react with and bond to the epoxy group-containing acrylic copolymer (II), the silicate compound (i), and the resin (ii) obtained by grafting the silicate compound, as described later. Obtainable. in this case,
Those having an average of 0.1 or more hydroxyl groups in one molecule are preferred.

The carboxyl group-containing polyester resin (III) is preferably contained in an amount of 5 to 70% by mass based on the total amount of the resin components. If the amount is less than 5% by mass, a large amount of an organic solvent is used at the time of coating, which may adversely affect the environment. If the amount exceeds 70% by mass, the weather resistance of the coating film decreases. Preferably, it is 5 to 50% by mass, more preferably 10 to 40% by mass. The above mass%
Is a value in terms of solid content.

In the resin component in the acid / epoxy-curable clear coating composition used in the present invention, [the total number of epoxy groups of the epoxy group-containing acrylic copolymer (II)] / [the half ester acid group-containing acrylic copolymer] (I) and the total number of the half-esterified acid anhydride groups and carboxyl groups of the carboxyl group-containing polyester resin (III)] = 0.5 to 1.5, particularly preferably 0.6 to 1.3. Also, [total number of hydroxyl groups in the epoxy group-containing acrylic copolymer (II)] / [total number of half-esterified acid anhydride groups in the half-ester acid group-containing acrylic copolymer (I)] = 0.1 ~ 1.5, especially 0.3 ~
It is preferably 1.2.

More specifically, the amount of the epoxy group-containing acrylic copolymer (II) giving such a ratio is, for example, the half ester acid group-containing acrylic copolymer (I) and the carboxyl group-containing acrylic copolymer. It is preferably from 50 to 250 parts by mass, particularly preferably from 80 to 150 parts by mass, based on 100 parts by mass of the polyester resin (III) in total. When the blending amount of the epoxy group-containing acrylic copolymer (II) is less than 50 parts by mass, the coating film is not sufficiently cured, and the water resistance and weather resistance of the cured coating film are reduced. If the amount exceeds the above range, unreacted carboxyl groups remain and the chemical resistance decreases.

[0074]Solid color paint  In the present invention, a coating having a hydrophilic or hydrophilizable coating surface is provided.
The base material to be coated is the one to which
If a solid color paint is used as the
Is included. The above solid color paint has a hydroxyl group
Containing acrylic resin and / or polyester resin containing hydroxyl group
30-85% by mass of fat and 15-70% by mass of curing agent
Is preferably a resin component.

The above-mentioned hydroxyl group-containing acrylic resin can be obtained by copolymerizing a hydroxyl group-containing acrylic monomer and another ethylenically unsaturated group-containing monomer by a usual method. The hydroxyl group-containing acrylic monomer is not particularly limited, and examples thereof include those described above.
The other ethylenically unsaturated group-containing monomer is not particularly limited. For example, in addition to the above-mentioned other monomers (Id), an epoxy group-containing monomer such as glycidyl (meth) acrylate may be used. And the like. These may be used alone or in combination of two or more.

The above-mentioned hydroxyl group-containing polyester resin can be obtained by polycondensing an acid component containing a polyhydric carboxylic acid as a main component and an alcohol component containing a polyhydric alcohol as a main component by an ordinary method. The acid component is not particularly restricted but includes, for example, terephthalic acid, isophthalic acid, phthalic acid and anhydrides thereof; aromatic dicarboxylic acids such as 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid and the like; Anhydrides; aliphatic dicarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid; and anhydrides thereof; lactones such as γ-butyrolactone and ε-caprolactone; aromatic oxymonocarboxylic acids such as p-oxyethoxybenzoic acid;
3 of trimellitic acid, trimedic acid, pyromellitic acid, etc.
Or higher polyvalent carboxylic acids; and corresponding hydroxycarboxylic acids and the like. These may be used alone or in combination of two or more.

The alcohol component is not particularly restricted but includes, for example, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,5-hexanediol, diethylene glycol and triethylene glycol. Glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, bisphenol A alkylene oxide adduct, bisphenol S alkylene oxide adduct; 1,2-propanediol, neopentyl glycol, 1,2-butanediol, 1,3-butanediol, 1,2-pentanediol, 2,3-pentanediol, 1,4-pentanediol, 1,4-hexanediol, 2,5-hexanediol, 3-methyl-1,5-pentane Diol,
Aliphatic glycols having a side chain such as 1,2-dodecanediol and 1,2-octadecanediol; trihydric or higher polyhydric alcohols such as trimethylolpropane, glycerin and pentaerythritol; These may be used alone or in combination of two or more.

The hydroxyl group-containing acrylic resin and the hydroxyl group-containing polyester resin preferably have an acid value of 100 mg KOH / g or less, a number average molecular weight (Mn) of 800 to 8000, and a hydroxyl value of 30 to 200 mg KOH / g. When the acid value exceeds 100 mgKOH / g, the viscosity of the resin is too high to make handling difficult, and a large amount of organic solvent is used at the time of coating, which may adversely affect the environment. If the hydroxyl value is less than 30 mgKOH / g, the curability of the coating will be insufficient, and if it exceeds 200 mgKOH / g, the water resistance of the coating film will decrease. Number average molecular weight (M
When n) is less than 800, the strength of the coating film decreases or the water resistance of the coating film decreases, and when it exceeds 8000, the viscosity of the hydroxyl group-containing acrylic resin becomes too high and handling becomes difficult. Use of an organic solvent may adversely affect the environment.

The curing agent is an amino resin and / or a blocked polyisocyanate compound. Preferred are amino resins alone or a combination of an amino resin and a blocked polyisocyanate compound. The amino resin is not particularly limited, and examples thereof include a melamine resin, a benzoguanamine resin, a glycoluril resin, and a urea resin. These may be used alone,
Two or more kinds may be used in combination. Among these, melamine resins and benzoguanamine resins are common.

The melamine resin can be alkyl-etherified into an alkyl-etherified melamine resin, and among them, a melamine resin substituted with a methoxy group and / or a butoxy group is preferable.

As the melamine resin substituted with the methoxy group and / or butoxy group, those having a methoxy group alone include Cymel 325, Cymel 327,
Cymel 370, mixed types of methoxy and butoxy groups include Cymel 202, Cymel 204, Cymel 232, Cymel 235, Cymel 236, Cymel 238, Cymel 254, Cymel 266, Cymel 2
67 (all trade names, manufactured by Mitsui Cytec Co., Ltd.).
(Trade name, manufactured by Mitsui Cytec), Uban 20N6
0, Uban 20SE (both trade names, manufactured by Mitsui Chemicals, Inc.) and the like. These may be used alone,
More than one species may be used in combination. In addition, the benzoguanamine resin described above can be similarly substituted.

The above blocked polyisocyanate compound is obtained by blocking a polyisocyanate compound with a blocking agent. The polyisocyanate compound is
It is not particularly limited as long as it is a compound having at least two isocyanate groups in the molecule, for example, aliphatic diisocyanates such as hexamethylene diisocyanate (HMDI) and trimethylhexamethylene diisocyanate (TMDI); isophorone diisocyanate (IPDI) Alicyclic diisocyanates; aromatic diisocyanates such as xylylene diisocyanate (XDI); aromatic diisocyanates such as tolylene diisocyanate (TDI) and 4,4-diphenylmethane diisocyanate (MDI); dimer acid diisocyanate (DD)
I), hydrogenated TDI (HTDI), hydrogenated XDI (H6XDI), hydrogenated MDI (H12M
Hydrogenated diisocyanates such as DI); dimers and trimers of these diisocyanate compounds; and polyisocyanates having a higher molecular weight; addition to polyhydric alcohols such as trimethylolpropane or water, or low-molecular-weight polyester resins Objects and the like. These may be used alone or in combination of two or more.

The blocking agent is not particularly limited.
For example, oximes such as methyl ethyl ketoxime, acetoxime, cyclohexanone oxime, acetophenone oxime and benzophenone oxime; phenols such as m-cresol and xylenol; methanol, ethanol, butanol, 2-ethylhexanol, cyclohexanol, ethylene glycol monoethyl ether and the like Alcohols; lactams such as ε-caprolactam; diketones such as diethyl malonate and acetoacetate; mercaptans such as thiophenol; ureas such as thiourea; imidazoles; and carbamic acids. These may be used alone or in combination of two or more.

The method for blocking the polyisocyanate compound with the blocking agent is not particularly limited, and includes, for example, a method in which the reaction is carried out by a usual method until the free isocyanate group disappears.

As the above-mentioned block polyisocyanate compound, commercially available products can be used. For example, Desmodur series (trade name, manufactured by Sumitomo Bayer Urethane Co., Ltd.) and Burnock D series (trade name, manufactured by Dainippon Ink and Chemicals, Inc.) , Takenate B series (trade name, manufactured by Takeda Pharmaceutical Company), Coronate 2500 series (trade name,
Manufactured by Nippon Polyurethane Industry Co., Ltd.). Among these, those blocked with an oxime, lactam or diketone are preferred.

When the curing agent is an amino resin, the mass ratio of the hydroxyl-containing acrylic resin to the amino resin is 8 /
It is preferably 2/5/5, preferably 7 / 3-6 / 4. In the case of a blocked isocyanate compound, the equivalent of the hydroxyl group of the hydroxyl group-containing acrylic resin is 0.1.
It is acceptable if the composition is such that the isocyanate group equivalent is in the range of 8 to 1.5 times. If the equivalent of the above hydroxyl value is less than 0.8 times, the curability of the coating is not sufficient, only a soft coating is obtained, and not only the hardness but also the chemical resistance and stain resistance of the coating are reduced. If it exceeds 1.5 times, not only the effect of adding the blocked polyisocyanate compound is not obtained, but also the strength, hardness, workability, chemical resistance, etc. of the coating film are reduced, and yellowing and weather resistance are also reduced. Easy to fall. Preferably, it is 1.0 to 1.2 times. When a blocked isocyanate compound is combined with an amino resin, the amount of the blocked isocyanate compound is preferably not more than half the mass of the amino resin.

In the present invention, the clear paint and the solid color paint need to form a hydrophilic or hydrophilizable coating film on the outermost surface of the base material. Therefore, an alkoxysilyl group and / or a silanol group are required. Must be contained. The component having an alkoxysilyl group and / or a silanol group is obtained by grafting a silicate compound (i) represented by the above formula (2) and / or a silicate compound represented by the above formula (2). It is preferably resin (ii).

[0088](I) silicate compound  The silicate compound (i) represented by the above formula (2) is
It is a compound that can be hydrophilized by water splitting. Equation (2) above
In the formula, m represents an integer of 1 to 30. R^Two Are different
May be represented by a hydrogen atom or a substituted or unsubstituted
Or an organic group having 1 to 20 carbon atoms having no substituent.
You. R above^Two At least one has a substituent or
Or an organic group having 1 to 20 carbon atoms having no substituent.
Is preferred.

In the above formula (2), when m exceeds 30, the resin (ii) obtained by grafting the silicate compound (i)
And the workability decreases. M is preferably from 5 to 25, from the viewpoint of setting the resin (ii) obtained by grafting the silicate compound (i) to an appropriate viscosity.

The above-mentioned organic group having 1 to 20 carbon atoms which has a substituent or no substituent is a silicate compound (i)
And the resin (ii) obtained by grafting it on the coating film surface in a wet coating film at the time of coating to make it more likely to be present in the vicinity of the coating film surface. From the viewpoint of reducing the solubility, those having 1 to 8 carbon atoms are preferable.

The above-mentioned organic group having 1 to 20 carbon atoms having a substituent or not having a substituent is not particularly limited.
And an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group and an acyl group. Among them, an alkyl group and an aralkyl group having 1 to 20 carbon atoms which have or do not have a substituent are preferable.

Examples of the above-mentioned or unsubstituted alkyl group include those exemplified above. Among these, a methyl group, an ethyl group, a propyl group, an isopropyl group, and an n-butyl group are preferred.

The above-mentioned or unsubstituted cycloalkyl group is not particularly limited.
Examples include a cyclopentyl group and a cyclohexyl group.
The aryl group is not particularly limited, and includes, for example, a phenyl group, a tolyl group, and a xylyl group.

The aralkyl group having a substituent or no substituent is not particularly limited, and examples thereof include a benzyl group, a 2-chlorobenzyl group, a 3-chlorobenzyl group, a 4-chlorobenzyl group, and a 2-bromobenzyl group. Benzyl group, 3
Halogenated benzyl groups such as -bromobenzyl group, 4-bromobenzyl group, 2-iodobenzyl group, 3-iodobenzyl group, 4-iodobenzyl group, dichlorobenzyl group; 2-methylbenzyl group, 3-methylbenzyl group , 4
-Methylbenzyl group, dimethylbenzyl group, 3,4,5
-Trimethylbenzyl group, 4-ethylbenzyl group, 4-
Isopropylbenzyl group, 4-butylbenzyl group, 4-
alkyl-substituted benzyl such as tert-butylbenzyl group; dimethoxybenzyl group, 2-ethoxybenzyl group,
3-ethoxybenzyl group, 4-ethoxybenzyl group, 4
-Butoxybenzyl group, 2-methoxybenzyl group, 3-
Alkoxy-substituted benzyl groups such as methoxybenzyl group and 4-methoxybenzyl group; phenethyl group, benzoin group,
Examples include benzyl groups and phenethyl groups of a phenylpropyl group. Among these, a benzyl group, a chlorobenzyl group, a methylbenzyl group, an ethylbenzyl group, and a methoxybenzyl group are preferred.

The acyl group having a substituent or no substituent is not particularly limited, and includes, for example, acetyl, propynol, butyryl, ethoxycarbonyl, propoxycarbonyl and the like.

A part or all of the above-mentioned or unsubstituted organic group having 1 to 20 carbon atoms may be a methyl group, an ethyl group, a methyl group, an ethyl group, or the like, from the viewpoint that the coating film exhibits sufficient hydrophilicity. Preferably it is a propyl group. Of these, a methyl group is most preferred. Further, from the viewpoint that the coating film exhibits sufficient hydrophilicity and has sufficient storage stability, it is more preferable that a part of the organic groups is a methyl group.

Specific examples of the above silicate compound (i) include tetramethoxysilane, tetraethoxysilane,
Tetra-n-propoxysilane, tetra-iso-propoxysilane, tetra-n-butoxysilane, tetra-
sec-butoxysilane, tetra-tert-butoxysilane, tetra-n-pentoxysilane, tetra-is
o-pentoxysilane, tetraneopentoxysilane and the like; one or more condensates thereof and the like.

Examples of the silicate compound (i) include those obtained by subjecting an alcohol exchange reaction to methyl silicate and / or a condensate thereof or ethyl silicate and / or a condensate thereof as a reaction substrate. In the present invention, such an alcohol-modified silicate compound is preferable. Examples of the condensate of methyl silicate or condensate of ethyl silicate include those exemplified above.

In the above-mentioned alcohol-modified silicate compound, methyl silicate and / or a condensate thereof, or ethyl silicate and / or a part of a methyl group or an ethyl group of the condensate thereof is modified by an alcohol exchange reaction. I have. In this case, in the above equation (2),
Part of R ² has a substituent or no substituent and has 2 to 20 carbon atoms, preferably 3 to 1 carbon atoms.
5, more preferably an alkyl group having 3 to 10 carbon atoms and / or
Or represents an aralkyl group having 7 to 20 carbon atoms, preferably 7 to 10 having or not having a substituent,
The remaining R ² represents a methyl group. If the number of carbon atoms is less than the above, the reactivity is too high, and the storage stability is deteriorated. If the number of carbon atoms exceeds the above, the hydrophilic function is not obtained. In the present invention,
Preferably, at least one of R ² is modified by an alcohol exchange reaction.

The alcohol exchange reaction is carried out by reacting the above-mentioned methyl silicate and / or its condensate or the above-mentioned ethyl silicate and / or its condensate as a reaction substrate with an alcohol compound as a reaction reagent.

Examples of the alcohol compound include a substituted or unsubstituted alkyl alcohol compound having 2 to 20, preferably 3 to 15 carbon atoms, a substituted or unsubstituted alkyl alcohol compound. Aralkyl alcohol compounds of the formulas 7 to 20 are exemplified. These may be used alone or in combination of two or more.

The above-mentioned alkyl alcohol compound having a substituent or no substituent and having 2 to 20 carbon atoms is not particularly restricted but includes, for example, ethyl alcohol, propyl alcohol, isopropyl alcohol, n-butyl alcohol and sec-butyl. Alcohol, tert-butyl alcohol, n-amyl alcohol, isoamyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, alkyl alcohol compounds such as 2-ethylhexyl alcohol; methyl cellosolve, ethyl cellosolve, butyl cellosolve, hexyl cellosolve, butyl diglycol, propylene Glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobu Ether alcohol compounds such as ether and the like. These may be used alone,
Two or more kinds may be used in combination.

Among these, propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec
Butyl alcohol; butyl cellosolve, methoxypropanol, ethoxypropanol is preferably used.

The aralkyl alcohol compound having 7 to 20 carbon atoms having a substituent or not having a substituent is not particularly limited.
Chlorobenzyl alcohol, 3-chlorobenzyl alcohol, 4-chlorobenzyl alcohol, 2-bromobenzyl alcohol, 3-bromobenzyl alcohol, 4-chlorobenzyl alcohol
Halogenated benzyl alcohols such as bromobenzyl alcohol, 2-iodobenzyl alcohol, 3-iodobenzyl alcohol, 4-iodobenzyl alcohol and dichlorobenzyl alcohol; 2-methylbenzyl alcohol, 3-methylbenzyl alcohol, 4-methylbenzyl alcohol; Dimethylbenzyl alcohol, 3,
Alkyl-substituted benzyl alcohols such as 4,5-trimethylbenzyl alcohol, 4-ethylbenzyl alcohol, 4-isopropylbenzyl alcohol, 4-butylbenzyl alcohol, and 4-tert-butylbenzyl alcohol; dimethoxybenzyl alcohol, 2-ethoxybenzyl alcohol; 3-ethoxybenzyl alcohol, 4-ethoxybenzyl alcohol, 4-butoxybenzyl alcohol, 2-methoxybenzyl alcohol,
Alkoxy-substituted benzyl alcohols such as 3-methoxybenzyl alcohol and 4-methoxybenzyl alcohol;
Phenethyl alcohol, benzoin, phenylpropanol and the like. These may be used alone,
More than one species may be used in combination.

Among them, benzyl alcohol, chlorobenzyl alcohol, methylbenzyl alcohol,
It is preferable to use ethylbenzyl alcohol and methoxybenzyl alcohol.

At the time of the alcohol exchange reaction, an alcohol exchange catalyst may be used. The alcohol exchange catalyst is not particularly limited, and includes, for example, an acid or a base. The acid is not particularly limited, and includes, for example, Bronsted acids such as hydrochloric acid, sulfuric acid, phosphoric acid, and sulfonic acid; and Lewis acids such as organic tin compounds. The base is not particularly limited and includes, for example, tertiary amines such as triethylamine, diisopropylethylamine, dimethylbenzylamine, diazabicyclo [2,2,2] octane, and 1,8-diazabicyclo [5,4,0] undecene-7. Amines and the like. These may be used alone or in combination of two or more.

The solvent used in the alcohol exchange reaction may not be particularly used. For example, an alcohol compound as a reaction reagent may be used as a solvent and used in excess of the reaction substrate. The solvent is not particularly limited, and examples thereof include aromatic hydrocarbons such as toluene, benzene, and xylene; halogenated hydrocarbons such as dichloroethane;
Ethers such as dioxane; ketones such as methyl ethyl ketone and methyl isobutyl ketone; esters such as ethyl acetate and butyl acetate; dimethyl carbamate and acetonitrile. These may be used alone,
Two or more kinds may be used in combination.

The amount of the solvent to be used is not particularly limited. For example, the total amount of methyl silicate as a reaction substrate and / or a condensate thereof, or ethyl silicate and / or a condensate thereof and an alcohol compound as a reaction reagent is used. It is preferably 10 times or less the mass.

The ratio of methyl silicate and / or its condensate, or ethyl silicate and / or its condensate, which is a reaction substrate in the alcohol exchange reaction, and the alcohol compound as a reaction reagent is not particularly limited. For example, the amount of the alcohol compound is at least 1 mol% based on the reaction substrate, and the amount required for denaturation may be an amount or more.

The alcohol exchange reaction may be carried out by azeotropically distilling off methanol or ethanol produced by denaturation. The reaction temperature of the alcohol exchange reaction is not particularly limited, and is generally 0 ° C to 20 ° C.
0 ° C. The reaction time is not particularly limited, but is preferably, for example, 24 hours or less. The pressure during the reaction is not particularly limited, and is generally normal pressure. However, if necessary, the reaction may be performed under reduced pressure to distill off generated methanol.

The reaction rate in the alcohol exchange reaction can be determined by measuring the amount of produced methanol, NMR spectrum or GC (gas chromatography) analysis. The product obtained as described above is generally a colorless to pale yellow oil.

The silicate compound (i) is preferably an alcohol-modified silicate compound obtained by an alcohol exchange reaction as described above. Other production methods include, for example, a polymerizable polysiloxane compound or a compound having a chain transfer ability. A silicate compound obtained by a method of copolymerizing a silane compound and a monofunctional monomer can also be used.

The silicate compound (i) is preferably a silicate compound obtained by subjecting a condensate of methyl silicate to alcohol modification, in view of the mechanism of developing hydrophilicity of the coating film.
The reason will be described in detail below. Since the methoxy group of the alcohol-modified silicate compound is apt to become a hydroxyl group with the passage of time, the water contact angle on the surface of the coating film decreases, and the coating film becomes hydrophilic. Therefore, it is considered that a contaminant attached to the surface of the coating film is easily washed away, and the coating film exhibits high stain resistance.

Further, due to the presence of the methoxy group, the alcohol-modified silicate compound has appropriate compatibility with other resin components, and exhibits sufficient stain resistance on the surface of the formed coating film.

Further, the alcohol-modified silicate compound obtained by the alcohol exchange reaction may be, for example, R ²
Is a methyl group, the methyl group of the tetramethyl silicate condensate is substituted with an alkyl group or an aralkyl group having a large number of carbon atoms in order from the most active methyl group, and the highly active portion is blocked. Compared to methyl silicate condensate, less likely to cause condensation reaction and other resin components during paint storage, excellent storage stability of the paint, the coating film obtained from the paint after storage also shows sufficient hydrophilicity, High stain resistance is stably exhibited even after storage on the coating film surface.

In the case where the overcoat paint used in the present invention contains the above-mentioned alcohol-modified silicate compound and is the above-mentioned acid / epoxy-curable paint, it is a reaction reagent used for obtaining the above-mentioned alcohol-modified silicate compound by the above-mentioned alcohol exchange reaction. A certain alcohol compound may be added as a solvent.

The amount of the alcohol compound to be added is 10 to 2 parts per 100 parts by mass of the silicate compound (i).
It is preferably 00 parts by mass. By adding the alcohol compound, it is possible to prevent the coating film from being abnormal in the heat curing step, and in the case of the resin (ii) obtained by grafting the following silicate compound, the top coat paint during storage is stabilized. Can be changed.

[0118]Resin obtained by grafting silicate compound
(Ii)  Instead of the silicate compound (i) represented by the above formula (2)
Or in combination with this, represented by equation (2)
The resin (ii) obtained by grafting a silicate compound is used.
Can be used. In the present invention, the acid / epo
Xy-curable clear paint and the above solid color paint
Is grafted with a silicate compound represented by the formula (2).
It is preferable to mix the resin (ii) consisting of: The above formula
Grafted silicate compound represented by (2)
Silicate compound grafted on resin (ii)
As the silicate compound (i)
it can. Due to the mechanism of developing hydrophilicity of the coating film, methyl silicate
Are preferred. In addition, the silica gel to be grafted is
As the salt compound, one kind may be used, and two or more kinds may be used.
A thing may be used.

The composition of the resin (ii) obtained by grafting the silicate compound is such that the silicate compound is grafted to at least one of the acid / epoxy curable clear paint or the resin component of the solid color paint. Or an acid / epoxy-curable clear paint or a paint prepared separately from the resin component of the solid color paint. Furthermore, it is also possible to combine the above compositions.

When the above silicate compound is used by grafting at least one of the resin components of an acid / epoxy curable clear coating, the silicate compound is grafted onto the half ester acid group-containing acrylic copolymer (I). A product obtained by grafting a silicate compound to an epoxy group-containing acrylic copolymer (II),
And carboxyl group-containing polyester resin (III)
And at least one selected from those obtained by grafting a silicate compound to the substrate.

In the case of solid color paints, those obtained by grafting a silicate compound to a hydroxyl group-containing acrylic resin and / or a hydroxyl group-containing polyester resin can be used.

The half-ester acid group-containing acrylic copolymer (I) and the epoxy group-containing acrylic copolymer (I)
It is only necessary that I) and / or a part of the carboxyl group-containing polyester resin (III) is grafted with the silicate compound, and it is not necessary that the entire copolymer is grafted, and the solid color paint is used. In this case, it is sufficient that a part of the hydroxyl group-containing acrylic resin is grafted with the silicate compound, and it is not necessary that all of the hydroxyl group-containing acrylic resin is grafted.

In these cases, there is no need to prepare a resin for grafting the silicate compound.
This is preferable in that the manufacturing process is simplified. In the case of the acid / epoxy-curable clear coating, when grafting onto the half-ester acid group-containing acrylic copolymer (I), the production of the half-ester acid group-containing acrylic copolymer (I) requires It is preferred that the radical polymerizable monomer be copolymerized to contain a hydroxyl group.

When the acid / epoxy curable clear coating is used, the crosslinking density is improved by the crosslinking reaction between the half-ester acid group-containing acrylic copolymer (I) and the grafted silicate compound. The epoxy group-containing acrylic copolymer (II) is preferably one obtained by grafting the above silicate compound.

When the resin (ii) obtained by grafting the above silicate compound is separately prepared and contained, a resin obtained by grafting the silicate compound to the hydroxyl group-containing polymer (ii-a) is used. The hydroxyl group-containing polymer (ii-
a) is not particularly limited as long as it is a polymer containing a hydroxyl group, and examples thereof include a hydroxyl group-containing acrylic resin, a hydroxyl group-containing polyester resin, and a hydroxyl group-containing alkyd resin. These may be used alone or in combination of two or more. The hydroxyl group-containing acrylic resin, the hydroxyl group-containing polyester resin and the hydroxyl group-containing alkyd resin are not particularly limited.For example, in the polycondensation of the same or polyester resin as described above, if necessary, semi-dry oil,
Those obtained by using non-drying oils and the like can be mentioned.

The semi-dry oil is not particularly limited, and examples thereof include soybean oil, safflower oil, tall oil and the like. The non-drying oil is not particularly limited, and examples thereof include coconut oil, castor oil and the like. These may be used alone or in combination of two or more. The hydroxyl group-containing polyester resin and the hydroxyl group-containing alkyd resin have an oil length of 40% or less. Preferably, the oil length is 30% or less.

The hydroxyl group-containing polymer (ii-a) may further have a carboxyl group, an epoxy group or the like as long as it has a hydroxyl group. The hydroxyl group-containing polymer (ii-
In a), the hydroxyl value is preferably from 20 to 200 mgKOH / g, and the number average molecular weight (Mn) is preferably from 500 to 10,000.

When the hydroxyl value is less than 20 mgKOH / g, the grafting efficiency and the amount of grafting are limited, and the
If it exceeds gKOH / g, the water resistance of the coating film will decrease. When the number average molecular weight (Mn) is less than 500, the strength of the coating film decreases, and when it exceeds 10,000, the viscosity of the coating material increases, the appearance decreases, or a large amount of an organic solvent is used during coating. Environmental load increases. Preferably, the hydroxyl value is 40 to 150 and the number average molecular weight is 800 to 8
000.

The method of the graft reaction is not particularly limited, and can be performed by a usual method. For example, the reaction may be performed without a solvent or in an organic solvent.

The organic solvent is not particularly restricted but includes, for example, alcohols such as methanol, ethanol, propanol and butanol; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran and dioxane; From the viewpoint that the solvent can be easily removed by the operation, those having a boiling point of 100 ° C. or less are preferable.

The reaction temperature and the reaction time in the above graft reaction differ depending on the type of the raw material, but are usually preferably in the range of room temperature to 150 ° C. and within 24 hours. If the reaction temperature is lower than room temperature, the silicate compound (i) is not sufficiently grafted, and if it exceeds 150 ° C. or exceeds 24 hours, condensation between the silicate compounds (i) occurs. The pressure in the graft reaction is 1 ×
Preferably, it is in the range of 10 ^{-3 to} 7600 Torr.

In the resin (ii) obtained by grafting the silicate compound, when the R ² O— group derived from the formula (2) is particularly a methoxy group, it easily becomes a hydroxyl group with the passage of time. The water contact angle is reduced, and the coating is rendered hydrophilic. Therefore, it is considered that a contaminant attached to the surface of the coating film is easily washed away, and the coating film exhibits high stain resistance. The resin (ii) obtained by grafting the above silicate compound due to the presence of the methoxy group and the like has appropriate compatibility with other resin components, and has sufficient stain resistance on the surface of the formed coating film. The character is exhibited.

Further, in the resin (ii) obtained by grafting the above silicate compound, the most reactive alkyl group of the above silicate compound reacts with the hydroxyl group in the above-mentioned polymer, and the most reactive alkyl group of the above silicate compound reacts. In order to block the high part, compared to the low condensate of tetramethyl silicate and / or tetraethyl silicate, during the storage of the paint less likely to react with the condensation reaction and other resin components,
Excellent storage stability of paint, coating film obtained from paint after storage also shows sufficient hydrophilicity, high stain resistance on the coating film surface,
It stably develops after storage.

When the resin (ii) obtained by grafting the silicate compound is a resin obtained by grafting the silicate compound to the above-mentioned resin component, the resin has excellent compatibility with other resin components in the coating material, and Since the localization of the hydrophilic group afterwards to the surface layer of the coating film is appropriately suppressed, compared with tetramethyl silicate and / or its low condensate,
Water resistance is improved.

[0135]Paint formulation  In the present invention, an acid / epoxy curable clear paint and
Silicates added to paints and solid color paints
Of the product (i) and the graft amount of the silicate compound
Is the silicate compound with respect to the total amount of each resin component.
(I) and the total amount of grafting of the silicate compound
0.1 to 50% by mass. Less than 0.1% by mass
The hydrophilicity of the coating film is not sufficient, and the stain resistance is poor.
If it exceeds 50% by mass, the coating film maintains excellent appearance.
May not have sufficient water resistance. Preferably
3 to 25% by mass, more preferably 5 to 20% by mass
It is. Note that the above mass% is a value in terms of solid content,
The total amount of the above resin components is a graph of the above silicate compound.
In the case of containing the resin (ii) prepared from the above,
The amount includes the polymer (ii-a).

The overcoat paint used in the present invention may be an acid /
When an epoxy-curable clear coating is used, a curing catalyst is usually included. The curing catalyst is not particularly limited, and may be a catalyst usually used for an esterification reaction (reaction between an acid and an epoxy). For example, a quaternary ammonium salt is preferable. Specifically, in addition to the above-mentioned quaternary ammonium salts, benzyltriethylammonium chloride, benzyltriethylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium bromide and the like can be mentioned. These may be used alone or in combination of two or more.

Further, in the case of a solid color paint as the top coat, the curing catalyst in the case of using a blocked polyisocyanate compound as a curing agent is not particularly limited. For example, dibutyltin laurate, dibutyltin octate, dibutyltin dioctane Organotin compounds such as acetate; aluminum tris (acetylacetonate), titanium tetrakis (acetylacetonate), titanium bis (acetylacetonate), titanium bis (butoxy) bis (acetylacetonate), titanium bis (isopropoxy) Metal chelate compounds such as bis (acetylacetonate), zirconium bis (butoxy) bis (acetylacetonate), zirconium bis (isopropoxy) bis (acetylacetonate) and the like. That. These may be used alone or in combination of two or more. Among these, organotin compounds are common.

When the amino resin is used as a curing agent, for example, aromatic sulfonic acids such as dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, p-toluenesulfonic acid; aminotri (methylenephosphonic acid), 1-hydroxy Organic phosphonic acids such as ethylidene-1,1-diphosphonic acid; curing catalysts such as amine salts thereof can be used. These may be used alone or in combination of two or more. The amount of the curing catalyst is preferably 0.01 to 3.0% by mass based on the total resin solids.

When the top coating is a solid color coating, it contains a pigment. In the case of the clear paint, the paint is usually free of a pigment, but may contain a colored pigment to the extent that the transparency of the coating film is not impaired. The pigment is not particularly limited and includes, for example, azo chelate pigments, insoluble azo pigments, condensed azo pigments, phthalocyanine pigments, indigo pigments, perinone pigments, perylene pigments, dioxane pigments, quinacridone pigments, and isoindo pigments. Organic color pigments such as linone pigments and metal complex pigments; inorganic color pigments such as yellow salt, yellow iron oxide, red iron oxide, carbon black and titanium dioxide; extender pigments such as calcium carbonate, barium sulfate, clay and talc. No. These may be used alone or in combination of two or more.

Rheology such as the melamine / formaldehyde resin for increasing the crosslink density and improving the water resistance, the ultraviolet absorber and the light stabilizer for improving the weather resistance of the coating film, and the like are used for the clear paint and the solid color paint. A microgel or a surface conditioner for control, a diluent for viscosity control or the like may be added. The compounding amount of the diluent is preferably 60% by mass or less, particularly preferably 55% by mass or less, based on the total mass of the coating material to which the diluent was added.

The ultraviolet absorber and light stabilizer are not particularly limited, and include, for example, Tinuvin-900 (manufactured by Ciba-Geigy), Sanol LS-292 (manufactured by Sankyo) and the like. The diluent is not particularly restricted but includes, for example, alcohol solvents such as methanol, ethanol, propanol and butanol; and solvents such as hydrocarbons and esters. These may be used alone or in combination of two or more.

The method for preparing the clear paint and the solid color paint is not particularly limited, and can be carried out by stirring each of the above-mentioned compounds with a stirrer or the like. It can also be carried out by kneading with use.

The solid content of the clear paint and the solid color paint is usually 40% by mass or more. Also,
The solid content at the time of application is usually 15 to 65% by mass.
It is.

The silicate compound (i) and / or the resin (ii) obtained by grafting the silicate compound may be added to and mixed with the paint before application. May be added and mixed. When it is added and mixed in the paint in advance, it is preferable to store it under conditions that do not allow water to mix so that hydrolysis and condensation reactions do not proceed.

[0145]Base paint  Base coating and clear coating as the top coating
When used, the base paint is not particularly limited.
For example, film-forming resins, curing agents, pigments and other additives
Can be mentioned. The above film-forming tree
The fat is not particularly limited. For example, acrylic resin,
Ester resin, alkyd resin, epoxy resin, urethane
Resin and the like. The above curing agent and it
As the curing catalyst used together, use the above-mentioned one.
be able to.

As the pigment, a coloring pigment, an extender pigment and / or a glitter pigment can be used alone or in combination of two or more. Examples of the color pigment and extender include those exemplified above. The glitter pigment is not particularly limited, and examples thereof include aluminum powder, copper powder, nickel powder, stainless steel powder, mica powder, interference mica powder, colored mica powder, alumina flake, graphite flake and the like. These may be used alone or in combination of two or more.

The solid content of the base paint is usually 6
0 mass% or less. Further, the solid content at the time of coating is usually 10 to 50% by mass. Additives that can be added to the base paint and its preparation method,
The above-mentioned thing etc. can be mentioned.

[0148]Coating method  In the present invention, the substrate has the hydrophilicity or the hydrophilicity.
Before forming a perfect coating film, it is responsible for corrosion resistance, chipping resistance, etc.
From the viewpoint of preservation, the undercoat coating layer (electrodeposition coating layer,
Indicates that an intermediate coating layer has been formed if necessary.
preferable.

In the present invention, other steps may be included as long as they include the above steps. Specifically, in the case of a base paint and a clear paint, after each is applied, baking and curing may be performed, or preheating may be performed. However, since the coating film forming method of the present invention is used for in-line repair or repainting of automobiles or the like, baking is necessary after applying the outermost clear paint or solid color paint.

It is also possible to form a two-coat, one-bake (2C1B) multi-layer coating film by applying the above base coating material, applying a clear coating material on a wet-on-wet basis, and curing by heating. it can. Further, when using two types of base paint, a color pigment-containing base paint called a color base paint and a glitter pigment-containing base paint, the above-mentioned color base paint is applied and heat-cured alone, and then the glitter pigment-containing base paint is applied thereon. The paint and clear paint can be applied wet-on-wet and cured by heating. Also, when the color base coating film is not to be cured by heating alone, the glitter pigment-containing base paint is applied thereon by wet-on-wet, and then the clear paint is further coated thereon by wet-on-wet and then heat-cured. It can also be done. That is, the color base coating film, the bright pigment-containing base coating film, and the clear coating film are combined in a wet-on-wet manner, and a composite coating film is formed and then heat-cured to form a three-coat one-bake (3C1B) composite. A coating film can be formed, and a composite coating film having more excellent design properties can be formed.

Further, the base coating material and the clear coating material may be applied wet-on-wet and cured by heating, and the clear coating material for top coating may be further applied thereon by wet-on-drying and then cured by heating. In this case, it is only necessary that the clear top coating applied to the outermost layer can form a hydrophilic or hydrophilic coating film.

The base paint, clear paint, and solid color paint can be applied by spray coating, brush coating, dip coating, electrostatic coating, roll coating, flow coating, or the like. Curing temperature is 100-180
C., preferably at 120 to 160.degree. C., to form a cured coating film having a high degree of crosslinking. The curing time varies depending on the curing temperature, etc.
A temperature of 120 to 160 ° C. for 10 to 30 minutes is suitable.

The dry film thickness of the base paint is generally preferably about 8 to 40 μm, more preferably 10 to 3 μm.
It is about 0 μm. If the dry film thickness is less than 8 μm, the base cannot be concealed.
Problems such as sagging may occur.

The dry film thickness of the clear paint and the solid color paint when the clear paint is not applied varies depending on the desired use.
0 μm is preferred, and more preferably about 15 to 60 μm. If the dry film thickness is less than 10 μm, the substrate cannot be concealed, and if it exceeds 60 μm, problems such as cracks and sagging may occur during coating.

In the present invention, a hydrophilizing agent containing a silanol group is applied to a substrate having a hydrophilic or hydrophilic surface of a coating film, so that the substrate can be treated as before rainfall. Stain resistance is exhibited even under conditions where the coating is not sufficiently hydrophilic. In addition, although the silicate compound and / or the resin grafted with the silicate compound remain in the polished surface, the hydrolysis has not sufficiently proceeded, and thus the silicate compound has not become hydrophilic. Is applied, the polished portion is also excellent in stain resistance.

Further, at the time of long-term exposure, the coating film of the hydrophilizing agent on the surface gradually dissolves and disappears due to rain, but the hydrophilic or hydrophilizable coating formed on the base material in advance. Since the film is sufficiently hydrophilic, the hydrophilicity can be maintained continuously. This means that the coating obtained by applying this hydrophilizing agent does not completely block moisture,
It is considered that the coating film provided thereunder supplies an amount of water capable of sufficiently hydrolyzing.

In the present invention, when the clear coating is an acid / epoxy-curable clear coating among the above top coatings, the following excellent effects can be expected. Since the acid / epoxy-curable clear coating used in the present invention has a modified acid anhydride group (half-esterified), even if an active hydrogen compound is mixed, no further reaction takes place and the one-pack (one-pack) Is possible. However, when a polymer containing only an acid anhydride group is used, the reaction with an active hydrogen compound proceeds even at around normal temperature, so that storage in the same system causes gelation and is not suitable.

In the curing reaction with an active hydrogen compound at the time of forming a coating film, the curing speed can be changed by changing the modifier of the acid anhydride group in various ways, and the coating film having an excellent appearance can be obtained. A film can be formed.

When the clear coating used in the present invention is an acid / epoxy-curable clear coating, the curing reaction is considered to proceed as follows. First, the half-esterified and ring-opened acid anhydride-modified group in the half-ester acid group-containing acrylic copolymer (I) is closed again at the curing temperature to return to the acid anhydride group. Next, the hydroxyl group in the epoxy group-containing acrylic copolymer (II) reacts to form a half ester again. Next, the remaining carboxyl groups in the half-ester acid group-containing acrylic copolymer (I) react with the epoxy groups in the epoxy group-containing acrylic copolymer (II) to form diesters.

Further, the R ² O— group in the silicate compound (i) and / or the resin (ii) obtained by grafting the silicate compound is changed by the acid catalysis of the half ester acid group-containing acrylic copolymer (I). At the same time as the hydrolysis-condensation, it reacts with the hydroxyl group in the epoxy group-containing acrylic copolymer (II) and cures.

That is, in the above curing reaction, two groups of the epoxy group and the hydroxyl group in the epoxy group-containing acrylic copolymer (II) are modified with the acid anhydride in the half ester acid group-containing acrylic copolymer (I). A silicate compound (i) and / or a resin obtained by grafting the silicate compound (i), which is bonded to a carboxyl group and an ester group which are groups, and a hydroxyl group in the epoxy group-containing acrylic copolymer (II).
It is considered that the curing progresses when two or three types of components are mutually reacted by bonding to each other and the hydrolysis-condensation product thereof.

When the acid / epoxy-curable clear coating composition further comprises the carboxyl group-containing polyester resin (III) as a resin component, the resin component described above and the carboxyl group-containing polyester resin (II)
In both cases, it is considered that the curing proceeds by reacting with each other.

On the other hand, when the top coat is a solid color paint, the curing reaction includes a silicate compound (i) and / or a resin (ii) obtained by grafting the silicate compound in addition to the curing reaction between the hydroxyl group-containing acrylic resin and the curing agent. the presence R ² O-groups of the catalyst in the curing by reacting with the hydroxyl group-containing acrylic resin and a curing agent at the same time as hydrolysis condensation is thought to proceed. Therefore, the cured coating film formed by the coating film forming method of the present invention has a firm structure, and has excellent weather resistance, chemical resistance, scratch resistance, and the like.

Further, when an alcohol-modified silicate compound is used as the silicate compound (i), or when a resin (ii) obtained by grafting the above silicate compound is used, a condensation reaction or other resin during the storage of the paint is required. Since it does not easily react with the components, it has excellent storage stability.

An automobile body having a coating film formed by the coating film forming method of the present invention has basic properties such as weather resistance, chemical resistance, and scratch resistance, and has high hydrophilicity. Not only is it difficult for dirt to adhere, but the same effect as that obtained by washing a car due to rain can be obtained, maintenance-free operation can be performed, and water resistance is excellent. Such an automobile body is also one of the present invention.

[0166]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In addition,% shows mass%.

Synthesis Example 1 Hydrophilizing agent A “MKC silicate MS51” (Methyl silicate condensate manufactured by Mitsubishi Chemical Corporation, SiO ₂ content: 51%; formula (1)
Is an average value of 5) 100 g of tris (2,
2.5 g of a 10% ethanol solution of 4-pentanedionate) aluminum was added and dissolved. This mixture 1.5
g to polyethylene glycol monolauryl ether (repeating number of ethylene oxide unit: 10; HLB1
4.1) 0.0285 g (0.05% by mass based on water)
Was dissolved in 41 g of ethanol. Then water 57
g was added gradually, stirred, and left overnight at room temperature to obtain a hydrophilizing agent A.

Synthesis Examples 2 to 7 Hydrophilizing Agents BG In Synthesis Example 1, the nonionic surfactants were
In the same manner except that the types and amounts shown in are used, the hydrophilizing agents B to E and the comparative hydrophilizing agents F and G were used.
I got

[0169]

[Table 1]

Synthesis Example 8 Half Ester Acid Group-Containing Acrylic Copolymer 330 g of xylene and 110 g of propylene glycol monomethyl ether acetate were charged into a 3 L reactor equipped with a thermometer, a stirrer, a cooling pipe, a nitrogen inlet pipe, and a dropping funnel. The temperature was raised to 127 ° C. Using a dropping funnel, 300 g of styrene, 360 g of 2-ethylhexyl methacrylate, 112 g of isobutyl acrylate, 26 g of acrylic acid, 202 g of maleic anhydride, 300 g of propylene glycol monomethyl ether acetate and 300 g of t-butyl peroxy-2- Ethyl hexanoate 90
g and 100 g of xylene was added dropwise over 3 hours.

After maintaining at 127 ° C. for 30 minutes after the completion of the dropwise addition, a solution comprising 10 g of t-butylperoxy-2-ethylhexanoate and 50 g of xylene was added dropwise over 30 minutes. After the completion of the dropwise addition, 127 ° C. for another hour.
The reaction was continued to obtain a varnish containing 53% of nonvolatile matter containing acrylic polyanhydride having a number average molecular weight (Mn) of 3000.

To 1990 g of the obtained varnish, 100 g of methanol was added and reacted at 70 ° C. for 23 hours to obtain an acid value of 12
A varnish containing 7 mg KOH / g (in terms of solid content) of a half ester acid group-containing acrylic copolymer was obtained. The half-ester acid group-containing acrylic copolymer was measured for its infrared absorption spectrum to determine the absorption of acid anhydride groups (1785).
cm ^-1 ) was confirmed to have disappeared.

Synthesis Example 9 Carboxyl group-containing polyester resin Pentaerythritol 136 was added to a reaction layer equipped with a thermometer, a stirrer, a cooling pipe, a nitrogen inlet pipe, a water separator and a rectification tower.
g, ε-caprolactone 456 g and dibutyltin oxide 0.1 g were charged, and the temperature was raised to 170 ° C. and maintained at 170 ° C. for 3 hours. Thereafter, 539 g of hexahydrophthalic anhydride dissolved by heating was added, the mixture was kept at 150 ° C. for 1 hour, and then ethyl 3-ethoxypropionate 464 was added.
g, the number average molecular weight (Mn) is 1700, the weight average molecular weight (Mw) / the number average molecular weight (Mn) is 1.28, the acid value is 174 mgKOH / g (in terms of solid content), and the hydroxyl value is 25 m.
A varnish having a nonvolatile content of 71% and containing a carboxyl group-containing polyester resin of gKOH / g (in terms of solid content) was obtained.

Synthesis Example 10 Epoxy Group-Containing Acrylic Copolymer 500 g of xylene was charged into a 2 L reaction tank equipped with a thermometer, a stirrer, a cooling tube, a nitrogen inlet tube and a dropping funnel.
The temperature was raised to 5 ° C. Using a dropping funnel, 380 g of glycidyl methacrylate, 200 g of styrene, 292 g of 2-ethylhexyl methacrylate,
128 g of 4-hydroxybutyl and 100 g of t-butylperoxy-2-ethylhexanoate and xylene 10
0 g of the solution was added dropwise over 3 hours. After maintaining at 125 ° C. for 30 minutes after the completion of the dropwise addition, a solution composed of 10 g of t-butylperoxy-2-ethylhexanoate and 10 g of xylene was added dropwise over 30 minutes. After completion of the dropwise addition, the reaction was continued at 125 ° C. for another hour,
Number average molecular weight (Mn) 3700, epoxy equivalent 400
(Non-volatile content including epoxy group-containing acrylic resin having a hydroxyl value of 47 mgKOH / g (solid content))
2% varnish was obtained.

Synthesis Example 11 Silicate-Grafted Acrylic Resin The inside of a 1 L reaction vessel equipped with a thermometer, a stirrer, a cooling pipe and a nitrogen introduction pipe was replaced with nitrogen gas, and MS-56 (trade name, manufactured by Mitsubishi Chemical Corporation) was used as methylsilicate. In the formula (2), m is 10) 100 g as an average value, and Synthesis Example 1
270 g of the epoxy group-containing acrylic copolymer obtained in Step 0 is added, and a graft reaction is carried out at 90 ° C. for 12 hours, and a silicate graft polymer which is an epoxy group-containing acrylic copolymer obtained by grafting a hydrolyzable silicate compound is included. A varnish having a nonvolatile content of 72% was obtained.

Synthesis Example 12 Preparation of Clear Coating Each of the components was charged according to the following formulation (the blending amount is a resin solid content), and the mixture was stirred with a disper to obtain a clear coating. Half-ester acid group-containing acrylic copolymer 30.8 g Carboxyl group-containing polyester resin 20.0 g Epoxy group-containing acrylic copolymer 34.1 g Silicate-grafted acrylic resin 26.6 g The resulting clear coating was butyl acetate / xylene = 1 /
No.1 thinner, Ford Cup No. The dilution and adjustment were carried out at 4 with a coating viscosity of 20 seconds.

Synthesis Example 13 Polyester Resin Trimethylolpropane 12.4 was placed in a reaction vessel equipped with a thermometer, a stirrer, a cooling pipe, a nitrogen introduction pipe, and a dropping funnel.
g, neopentyl glycol 21.5 g, hydroxypropionate neopentyl glycol ester 8.3 g,
Hexahydrophthalic anhydride 28.7 g, Cardura E-
9.3 g of 10 (manufactured by Shell Chemical), 20.6 of isophthalic acid
g, 0.02 g of dibutyltin oxide, 18
The temperature was raised to 0 ° C. While raising the humidity from 180 ° C. to 230 ° C. over 3 hours, the reaction water generated by the esterification reaction is distilled out of the system. The reaction was continued at 230 ° C, and the acid value was 10
And the reaction was cooled to 120 ° C. Praxel M
18.1 g (manufactured by Daicel Corporation) was charged, and the mixture was stirred at 150 ° C. for 2 hours to complete the transesterification reaction. Thereafter, the mixture was cooled to 100 ° C. and dissolved with 37 g of xylene to obtain a polyester resin. The obtained polyester resin has a nonvolatile content of 74.5% and a solid content of 8 mgKOH /
g, number average molecular weight 2100.

Synthesis Example 14 Preparation of Solid Color Paint A white solid paint was obtained by the following formulation (the blending amount is a resin solid content), and then Solvesso 100 (manufactured by Esso Standard Oil Co., Ltd.) / Butyl acetate = 1/1. By thinner, Ford Cup No. The dilution was adjusted to a coating viscosity of 23 seconds with 4. Polyester resin 56 g Uban 128 (Mitsui Chemicals, melamine resin) 30 g Titanium oxide 40 g

Examples 1 to 5 and Comparative Examples 1 to 3 Cathodic electrodeposition paint Powertop V-20 manufactured by Nippon Paint Co., Ltd. and polyester / melamine gray intermediate coating paint Olga H-870 (all trade names) were applied to phosphoric acid-treated steel sheets. ) Was applied on a test plate which was coated so as to have a dry film thickness of 25 μm and 40 μm, respectively, and cured by heating. A silver metallic base paint of Olga H-300-18G (trade name) manufactured by Nippon Paint Co., Ltd. was applied to an electrostatic coating machine AutoREA. (Product name,
Ransburg Co., Ltd.) at an atomizing pressure of 5 kg / cm ² , and after setting for about 7 minutes, the clear paint obtained in Synthesis Example 12 is applied thereon by wet-on-wet spraying and set for about 7 minutes Thereafter, baking and drying were performed at 140 ° C. for 30 minutes, and first-coated test plates of 2 coats and 1 bake (2C1B) were prepared as coating methods, and left in a desiccator for 30 minutes. The water contact angle of the clear film after standing for 30 minutes was 86 degrees. The cured coating film of the base paint and the clear paint was applied so that the dry film thickness was 15 μm and 40 μm, respectively.

Subsequently, each of the hydrophilizing agents A to G obtained in Synthesis Examples 1 to 7 was applied to a coated test plate by spraying so as to have a dry film thickness of 0.1 to 0.5 μm. Dry for 5 minutes. The obtained multilayer coating film was evaluated by the following evaluation method. The results are shown in Table 2. Comparative Example 3
Did not use a hydrophilizing agent.

[0181]Evaluation method  (1) Measurement of water contact angle immediately after coating and drying and evaluation of wettability The water contact angle of the test plate obtained above was measured. More wet
The reversibility was visually evaluated. (2) Outdoor exposure pollution resistance test An outdoor exposure test was conducted in accordance with JIS K5400 9.9.
After 2 weeks, January and June, the water contact angle and initial
The lightness difference (ΔL) from the initial coating film was measured.

[0182]

[Table 2]

Examples 6 to 8 and Comparative Examples 4 to 5 The white solid paint obtained in Synthesis Example 14 was applied to the intermediate coated plate (not coated with the base paint and the clear paint) obtained in Example 1. It was applied by spraying, set for about 7 minutes, baked and dried at 140 ° C. for 30 minutes, and then left for 30 minutes in the same manner as in Example 1. After 30 minutes, the water contact angle was 86 °. In addition, the cured coating film of the white solid paint was applied so that the dry film thickness became 40 μm. Subsequently, the hydrophilizing agent A shown in Synthesis Examples 1 to 3 and 6
~ C and F are each applied to the painted test plate by spraying, and 6
Dry at 0 ° C. for 5 minutes. Evaluation was performed in the same manner as in Example 1,
The results are shown in Table 3. In Comparative Example 5, no hydrophilizing agent was used.

[0184]

[Table 3]

As is clear from Tables 2 and 3, Example 1
The multi-layer coating film formed in Nos. 8 to 8 has a water contact angle of 40 ° or less at an early stage and acquires hydrophilicity due to the hydrophilic treatment agent coated on the surface, and stains adhere even after 6 months. Did not. Comparative Examples 1, 2, and 4 using a surfactant having an HLB outside the range of 10 to 15 and Comparative Examples 3 and 5 using no hydrophilizing agent had uneven wettability, and / or Alternatively, it took a long time before the water contact angle was high and the stain resistance was exhibited. Therefore, in Comparative Examples 1 to 5, dirt was attached before the hydrophilicity of the clear coating film or the solid color coating film was improved after about 6 months.

[0186]

As described above, the method for forming a coating film of the present invention has the above-mentioned structure. Therefore, the hydrophilicity-imparting agent applied to the surface has a high hydrophilicity-imparting rate and exhibits stain resistance even before rainfall. ,
In addition, the polished surface has excellent stain resistance, and the stain resistance is maintained for a long time. In addition, since it has a high crosslinking density, it also has basic performance such as weather resistance. The vehicle body of the present invention exhibits excellent appearance and coating film performance, and can be maintenance-free without requiring car washing.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) C09D 201/10 C09D 201/10 (72) Inventor Hisayuki Tanabe 19-17 Ikedanakamachi, Neyagawa-shi, Osaka, Japan Inside Paint Co., Ltd. (72) Inventor Satoshi Urano 19-17 Ikedananakacho, Neyagawa-shi, Osaka Japan F Co., Ltd. F-term (reference) 4D075 AE06 BB24Z BB92Z CA34 CA37 CB06 CB14 DA23 DB02 DC12 EA06 EA43 EB43 EB45 EC30 EC35 EC37 EC52 EC54 4J038 CC021 CG141 CG171 CH031 CH041 CH121 CH171 CP091 DA111 DB221 DD041 DG301 DL021 DL131 GA06 GA07 JB01 JC13 JC38 KA03 KA06 KA08 MA12 MA14 NA01 NA03 NA05 NA06 NA27 PA07 PA19 PB07 PC08

Claims (8)

[Claims] 1. A method for forming a coating film comprising a step of applying a hydrophilic treatment agent on a substrate having a hydrophilic or hydrophilizable coat surface and drying the same, wherein the hydrophilic treatment agent comprises: It contains a hydrolyzate of a silicate compound represented by the following formula (1), a nonionic surfactant, water and a hydrophilic organic solvent, wherein the nonionic surfactant has an alkylene oxide unit, HLB is 10-15, The quantity with respect to the said water is 0.02-10 mass%, The coating film formation method characterized by the above-mentioned. Embedded image (In the formula, n represents an integer of 1 to 30; R ¹ may represent a different group, and represents a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms.) 2. The method according to claim 1, wherein the content of the hydrolyzate of the silicate compound is 0.05 to 10% by mass in the hydrophilizing agent. 3. The substrate having a hydrophilic or hydrophilizable coating film surface is obtained by applying a top coat to the substrate,
The top coating is composed of a base coating and a clear coating. The application of the top coating is to apply the base coating and the clear coating in this order, and the clear coating is represented by the following formula (2). And (ii) a resin obtained by grafting a silicate compound (i) represented by the following formula (2):
The method for forming a coating film according to claim 1, comprising: Embedded image (In the formula, m represents an integer of 1 to 30; R ² may represent a different one, and may be a hydrogen atom or a substituted or unsubstituted organic group having 1 to 20 carbon atoms. Represents a group) 4. The clear paint contains a resin (ii) obtained by grafting a silicate compound represented by the formula (2), and comprises a half ester acid group-containing acrylic copolymer (I) and an epoxy group. -Containing acrylic copolymer (II)
4. The method for forming a coating film according to claim 3, comprising: 5. A substrate having a hydrophilic or hydrophilizable coating film surface, wherein the substrate is coated with an overcoat paint,
The top coat is a solid color paint, and the solid color paint is a silicate compound (i) represented by the following formula (2) and / or a silicate represented by the following formula (2). 3. The method for forming a coating film according to claim 1, comprising a resin (ii) obtained by grafting a compound. Embedded image (In the formula, m represents an integer of 1 to 30; R ² may represent a different one, and may be a hydrogen atom or a substituted or unsubstituted organic group having 1 to 20 carbon atoms. Represents a group) 6. The solid color paint is a resin (ii) obtained by grafting a silicate compound represented by the formula (2).
The method according to claim 5, further comprising a curing agent. 7. The method for producing a hydrophilic film, comprising:
Claim 1, 2, 3, 4, which is applied to 0 µm.
7. The coating film forming method according to 5 or 6. 8. A vehicle body having a coating film formed by the coating film forming method according to claim 1, 2, 3, 4, 5, 6, or 7.