JPH11128828A - Method for forming metallic coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming a metallic coating which does not cause decrease in leafing property or aggregation fracture of a coating liquid even in long-term storage, which shows excellent brightness and flip-flop property and improved interlayer adhesion with a clear coating film. SOLUTION: An org. solvent-based base coating material and an org. solvent dispersion liquid of leafing aluminum flakes are mixed just before application, and the mixture is applied on the objective surface. The components are mixed just before applying, and the mixture is applied on the surface and hardened by heating. Then an overcoating material is applied thereon. Or, the components are mixed just before applying, and the mixture is applied on the objective surface and hardened by heating. Then an overcoating material comprising a colorless or color transparent coating material containing a phosphate group- contg. resin compsn. is applied thereon, and further a transparent overcoating material is applied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for forming a metallic coating film containing a leafing type aluminum flake pigment (hereinafter referred to as "leafing aluminum").

[0002]

[Prior art and its problems] Acrylic melamine resin,
Polyester melamine resin and polyol resin
Resin compositions for paints such as isocyanate compounds
Metallic paints mixed with finning aluminum are known, and when this paint is applied, the leaching aluminum floats on the surface layer of the coating (this is called rifling) and forms a chrome-plated coating. It is known that a metallic coating film that can be finished, is excellent in glitter, and has a strong flip-flop property (FF property) is formed.

[0003] However, this metallic paint has a defect that the reefing property of the refining aluminum gradually decreases when stored for a long time.

[0004] This coating film alone has poor acid resistance and the like because the leafing aluminum is floating on the surface layer thereof, and it is difficult to apply it as a top coating film on an automobile outer panel. In order to prevent deterioration, it is necessary to apply a clear paint to the painted surface. At that time, if clear coating is applied to the uncured coating surface, the orientation of the leafing aluminum will be disturbed and the chrome plating tone will be reduced (this is called the “modification phenomenon”). However, there has been a problem that the interlayer adhesion is not sufficient, and a method for sufficiently exhibiting the above-mentioned effects of the leafing aluminum has not been found.

There is also a method in which a resin composition for paint is separated from leafing aluminum, a resin solution for paint is applied first, and then an organic solvent dispersion of leafing aluminum is applied to the uncured coating surface. However, there is a defect that the leafing aluminum is multi-layered and cohesive failure is likely to occur.

[0006]

SUMMARY OF THE INVENTION In view of the above-mentioned situation, the present inventors have considered that even if the reefed aluminum is stored for a long time, the releasable aluminum will not be removed.
It does not reduce the finging property, does not cause cohesive failure, and does not reduce the effect of the refining aluminum (for example, finish in chrome plating tone, strong glitter and strong flip-flop), and does not reduce the interlayer between the clear coating film. We conducted intensive research on a method of forming a metallic coating film with improved adhesion.

As a result, the resin composition for coating and the leafing aluminum are separated in advance, and they are mixed immediately before coating, and the resulting mixture is coated, without reducing the effect of the leafing aluminum. It was found that a reduction in the reefing property could be prevented. In addition, they have found that by including a phosphate group-containing resin composition in the resin composition for coatings, the interlayer adhesion with a clear coating film is improved, thereby completing the present invention.

Thus, the gist of the present invention is as follows.

1: An organic solvent-based coating composition (A) containing a resin composition for coating composition and a dispersion (B) obtained by dispersing leafing aluminum flakes in an organic solvent are separated in advance. A method of forming a metallic coating film (method 1 of the present invention), wherein the two components (A) and (B) are mixed immediately before coating, and the mixture is applied to the surface to be coated.

2: A method for forming a metallic coating film comprising curing the metallic coating film obtained by the method 1 of the present invention, and then applying a colorless transparent or colored transparent top coat (C) (the method 2 of the present invention). .

3: After heat-curing the metallic coating film obtained by the method 1 of the present invention, a colorless transparent or colored transparent top coat (C) containing a phosphate group-containing resin composition is applied, and then a colorless transparent or A method for forming a metallic coating film, which comprises applying a colored transparent top coat (D) (method 3 of the present invention).

Hereinafter, methods 1 to 3 of the present invention will be described.

Method 1 of the present invention: an organic solvent-based base paint (A) containing a resin composition for a paint, and
Dispersion (B) obtained by dispersing fing aluminum flakes is separated in advance, the two components (A) and (B) are mixed immediately before coating, and the mixture is coated on the surface to be coated. Is a method for forming a metallic coating film.

The base paint (A) is a paint which is mixed with a dispersion liquid (B) described below immediately before coating and applied to an object to be coated. The base paint (A) contains a resin composition for coating and an organic solvent. Fing aluminum is not substantially contained.

The resin composition for a coating comprises a base resin and a cross-linking agent, and a cross-linking curable resin composition usually used in the field of coatings can be applied.

As the base resin, for example, an acrylic resin, a polyester resin, an alkyd resin, a fluororesin, a urethane resin, a silicone-containing resin containing a crosslinkable functional group such as a hydroxyl group, a carboxyl group, a silanol group, an epoxy group, etc. And especially preferred are acrylic resins containing these crosslinkable functional groups. Examples of the crosslinking agent include a melamine resin, a urea resin, a (block) polyisocyanate compound, an epoxy compound, a carboxyl group-containing compound, an acid anhydride, and an alkoxysilane group-containing compound that react with the crosslinkable functional group of the base resin. Can be used. Among these, as the melamine resin, a part or all of the methylol group of methylolated melamine has 1 to 1 carbon atoms.
8 is a portion etherified with a monohydric alcohol or a fluorinated melamine resin, and the triazine nucleus is 1 to
Those having five are preferred. Imino group-containing melamine resins can also be used. The ratio between these base resin and crosslinking agent is
Based on the total solids content of both components, the former is suitably from 50 to 90% by weight, especially from 65 to 80% by weight, the latter from 50 to 10% by weight, especially from 45 to 20% by weight.

As the organic solvent, those generally used in the field of paints can be applied, and examples thereof include hydrocarbon-based, ester-based, alcohol-based, ketone-based and ether-based solvents.

In the method 1 of the present invention, the base paint (A)
By using the following "phosphoric acid group-containing resin composition" as a coating resin composition, the adhesiveness to leafing aluminum in the metallic coating and the interlayer adhesion to the upper coating film in the upper layer It is more preferable because the property is improved.

Examples of the "phosphate group-containing resin composition" include the following.

(P-1): A phosphate group-containing unsaturated monomer and a hydroxyl group-containing unsaturated monomer are used as constituents.
A polymer containing a phosphoric acid group and a hydroxyl group in one molecule.

(P-2): Polymer particles are dispersed in an organic solvent solution of a polymer dispersion stabilizer, and the polymer particles are
A phosphate group-containing non-aqueous dispersion, which is a polymer particle containing a phosphate group-containing unsaturated monomer unit as a constituent.

These (P-1) and (P-2) which can be used as the coating resin composition for the base coating (A) will be described.

The unsaturated monomer containing a phosphoric acid group used for preparing the polymer (P-1) contains a polymerizable unsaturated bond and a phosphoric acid group represented by the following formula (1) in one molecule. Is a compound having at least one of each.

Formula (1) -OPO (OH) (R ₁ ) (wherein R ₁ is a hydroxyl group, a phenyl group, or a group having 1 to 2 carbon atoms)
An alkyl group of 0. ) As such a phosphoric acid group-containing unsaturated monomer, for example, (2)
-Acryloyloxyethyl) acid phosphate,
(2-methacryloyloxyethyl) acid phosphate, (2-acryloyloxypropyl) acid phosphate, (2-methacryloyloxypropyl) acid phosphate, 10-acryloyloxydecyl acid phosphate, (Meth) acryloyloxyalkyl (C2-20) acid phosphates such as 10-methacryloyloxydecyl acid phosphate
And others. Further, an equimolar addition product of glycidyl (meth) acrylate and monoalkyl (C1-20) phosphoric acid can also be used as the unsaturated monomer containing a phosphate group.

The hydroxyl group-containing unsaturated monomer is a compound having a hydroxyl group and a polymerizable unsaturated bond in one molecule, for example, hydroxyethyl (meth) acrylate,
Monoesters of glycol having 2 to 20 carbon atoms, such as hydroxypropyl (meth) acrylate and hydroxybutyl (meth) acrylate, and (meth) acrylic acid are exemplified.

The polymer (P-1) contains the above-mentioned unsaturated monomer containing a phosphate group and the unsaturated monomer containing a hydroxyl group as essential components, and further contains other monomers and N- Those obtained by copolymerization using an alkoxymethylamide group-containing monomer and the like are included.

The other monomers are polymerizable unsaturated compounds other than the above-mentioned unsaturated monomers containing a phosphoric acid group, unsaturated monomers containing a hydroxyl group and the following monomers containing an N-alkoxymethylamide group. For example, (meth) acrylic acid and carbon number 1
And monoesters with monohydric alcohols of -22, styrene, acrylonitrile, vinyl acetate, vinyl chloride, (meth) acrylic acid, maleic acid, maleic anhydride and the like.

The N-alkoxymethylamide group-containing monomer is a compound having an N-alkoxymethylamide group and a polymerizable unsaturated bond in one molecule, for example, N-methoxymethyl (meth) acrylamide, N-ethoxy. Methyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N-propoxymethyl (meth) acrylamide and the like can be mentioned.

In the polymer (P-1), the ratio of the phosphate group-containing monomer to the hydroxyl group-containing monomer is 10 to 90%, preferably 20 to 90%, based on the total weight of both monomers. ~ 80%
And the latter is preferably 90 to 10%, particularly preferably 80 to 20%. In addition, the other monomer is a total of 100
1000 parts by weight or less, especially 10 to 500 parts by weight
It is suitable that the amount of the N-alkoxymethylamide group-containing monomer be 500 parts by weight or less, especially 10 to 300 parts by weight.

Further, copolymerization using a phosphoric acid group-containing unsaturated monomer and a hydroxyl group-containing unsaturated monomer, and if necessary, other monomers and an N-alkoxymethylamide group-containing monomer. The reaction is preferably solution polymerization, and the polymer (P-1) has a hydroxyl value of 5 to 150, particularly 10 to 100.
mgKOH / g, acid value based on phosphate group is 10-15.
0, in particular 15 to 130 mg KOH / g and a number average molecular weight of 1000 to 100,000, especially 3000 to 5000
It is preferably 0.

The polymer (P-1) becomes self-crosslinkable by using an N-alkoxymethylamide group-containing monomer in combination.

In the base coating material (A) containing the polymer (P-1), the polymer (P-1) containing no monomer containing an N-alkoxymethylamide group may be added to the N-alkoxymethylamide A compound containing a polymer containing a group-containing monomer as a crosslinking agent is also included. The latter polymer has an N-alkoxymethylamide group-containing monomer as a main component and can be used in combination with the other monomers described above, but does not substantially contain a phosphate group-containing monomer and a hydroxyl group-containing monomer. .

Further, the above-mentioned melamine resins and urea resins which can react with the hydroxyl groups of the polymer (P-1), polyisocyanate compounds which may be blocked, and the like can be used as crosslinking agents.

These polymers (P-1) are generally used in organic solvents such as hydrocarbon-based, ester-based, alcohol-based, ketone-based and ether-based solvents used in the field of coatings. It is used after being mixed and dissolved or dispersed.

The dispersion liquid (P-2) is obtained by dispersing polymer particles in a solution of a polymer dispersion stabilizer in an organic solvent, and the polymer particles comprise a phosphate group-containing unsaturated monomer unit. It is a phosphate group-containing non-aqueous dispersion which is a polymer particle contained as a component.

The polymer particles in the dispersion (P-2) are as follows:
It can be formed by polymerizing only a phosphate group-containing unsaturated monomer or a monomer component composed of a phosphate group-containing unsaturated monomer and another copolymerizable monomer.

The unsaturated monomer having a phosphoric acid group, which is a constituent of the polymer particles of the dispersion (P-2), is, for example, the one represented by the formula (1) described for the polymer (P-1). A compound having both a phosphoric acid group and a polymerizable unsaturated bond can be used.

Further, a compound represented by the following formula (2) can also be used as a phosphoric acid group-containing unsaturated monomer for preparing polymer particles of dispersion (P-2).

Formula (2): CH ₂ ＣCX—CO— (Y
O) n-OPO (OH) ₂ (wherein X is a hydrogen atom or a methyl group, Y is an alkylene group having 2 to 4 carbon atoms, and n is an integer of 3 to 30) Formula (2) The monomer represented by is, for example, a polyalkylene glycol monoester obtained by adding an alkylene oxide to (meth) acrylic acid, then reacting with phosphorus oxychloride to form a phosphoric acid monoester, and then hydrolyzing the product. It can be prepared by decomposition. Instead of this phosphorous oxychloride, orthophosphoric acid, metaphosphoric acid, phosphoric anhydride, 3
It is also possible to use phosphorus chloride and phosphorus pentachloride. Further, the amount of the alkylene oxide used can be a stoichiometric amount or more according to n in the formula (2).
It is preferably from 3 to 60 mol per 1 mol of (meth) acrylic acid. As the alkylene oxide, one having 2 to 4 carbon atoms is preferable, and examples thereof include ethylene oxide, propylene oxide, and butylene oxide.

The above addition reaction for preparing the monomer of the formula (2) is carried out usually at a temperature of 40 to 200 ° C. for 0.5
Can be completed in ~ 5 hours. The monoesterification reaction of phosphorus oxychloride after the addition reaction is, for example, 0 to 10
At a temperature of 0 ° C., it can be completed in 0.5 to 5 hours. The amount of phosphorus oxychloride used may be approximately stoichiometric, but may be used within the range of 1 to 3 mol per mol of the adduct, if desired. Thereafter, the compound represented by the above formula (2) is obtained by hydrolysis in a conventional manner. Specific examples of the compound represented by the formula (2) include:
For example, acid phosphoxyhex (or dodeca)
(Oxypropylene) monomethacrylate and the like.

Compounds having at least one polymerizable unsaturated bond in one molecule can be used as other monomers copolymerizable with these polymerizable unsaturated monomers having a phosphate group. Specific examples include the following.

A) Esters of (meth) acrylic acid: for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate , (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, lauryl (meth) C _{1 ~ 18} alkyl esters of (meth) acrylic acid, such as stearyl acrylate; glycidyl (meth) acrylate glycidyl esters such as; allyl (meth) acrylate - bets such as (meth) C _{2 to 8} alkenyl esters of acrylic acid; hydroxyethyl (meth) acrylate - DOO, hydroxypropyl (meth) acrylate - bets such as (meth) C _{2 to 8} hydroxyalkyl esters of acrylic acid; allyl oxyethyl (meth) acrylate (Meth) C _{3 to 18} alkenyloxyalkyl esters of acrylic acid such as preparative; PLACCEL (PLACCEL) FA-1, FA-
2, FA-3, FA-4, FA-5, FM-1, FM-
2, _C2-8 hydroxyalkyl esters of (meth) acrylic acid and caprolactone, available under trade names such as FM-3, FM-4, FM-5, and FM-6 (manufactured by Daicel Chemical Industries, Ltd.) And diesters of (meth) acrylic acid with glycols such as ethylene glycol and propylene glycol.

B) Vinyl aromatic compounds: for example, styrene, α-methylstyrene, vinyltoluene, p-chlorostyrene, vinylpyridine, divinylbenzene and the like.

C) α, β-ethylenically unsaturated acid: (meth) acrylic acid, maleic acid, itaconic acid and the like.

D) (Meth) acrylamides: for example, (meth) acrylamide, n-butoxymethyl (meth) acrylamide, n-methylol (meth) acrylamide and the like.

E) Others: for example, acrylonitrile,
Methyl isopropenyl ketone, vinyl acetate, veova monomer (trade name, manufactured by Shell Chemical Co., Ltd.), vinyl propione
, Vinyl pivalate, isocyanate ethyl (meth)
Acrylate, perfluorocyclohexyl (meth) acrylate, p-styrenesulfonamide, N-methyl-p-styrenesulfonamide, γ-methacryloxypropyltrimethoxysilane and the like.

The monomer component for preparing the polymer particles in the non-aqueous dispersion (P-2) contains a phosphoric acid group-containing polymerizable unsaturated monomer as an essential component, and further contains other components as necessary. It is constituted by adding a copolymerizable monomer, and the ratio of these monomers is not particularly limited and can be arbitrarily changed according to the purpose. The former is 0.1 based on the sum of the monomers and other monomers.
1 to 100% by weight, especially 0.5 to 50% by weight, more particularly 3 to 30% by weight, and the latter 99.9 to 0% by weight, especially 99.5 to 50% by weight, more particularly 97 to 70% by weight.
It is preferably within the range of weight%.

The non-aqueous dispersion (P-2) can be prepared by polymerizing the above monomer components into particles in a solution of a polymer dispersion stabilizer in an organic solvent. A non-aqueous dispersion in which polymer particles derived from the above monomer components are dispersed in an organic solvent solution is obtained.

The polymer dispersion stabilizer is for stably dispersing the polymer particles in the dispersion,
Those which are compatible with the organic solvent in the dispersion but hardly compatible with the polymer particles containing the coexisting polymerizable unsaturated monomer unit having a phosphoric acid group as a component are used.

Examples of the polymer dispersion stabilizer include the following, and these can be used alone or in combination of two or more.

1) A glycidyl ester of (meth) acrylic acid is ester-added to a carboxyl group in a self-condensed polyester resin of a fatty acid having a hydroxyl group such as 12-hydroxystearic acid to give about one carboxylic acid per molecule. A polyester macromonomer (1a) having a polymerizable unsaturated bond introduced therein, and the macromonomer (1a)
Polymer (1b) obtained by polymerizing a polymerizable monomer on the polymerizable unsaturated bond in a). 2) A polymerizable monomer containing a glycidyl ester of (meth) acrylic acid is polymerized on the polyester macromonomer (1a), and an α, β-ethylenically unsaturated acid is added to the glycidyl group in the polymer. (2a) having a polymerizable unsaturated bond introduced by adding The amount of the polymerizable unsaturated bond to be introduced is usually 0.2 to 1.
Within two ranges is preferred.

3) A hydroxyl-containing acrylic resin obtained by polymerizing a monomer component containing an alkyl (meth) acrylic acid monoester (having 4 or more carbon atoms) and a hydroxyl-containing polymerizable monomer. 4) Hydroxyl-containing polymerizable monomers such as alkyl (meth) acrylate (having 4 or more carbon atoms) monoester, _C2-8 hydroxyalkyl esters of (meth) acrylic acid, and glycidyl ester of (meth) acrylic acid Acrylic resin (4) in which a polymerizable unsaturated bond is introduced by adding an α, β-ethylenically unsaturated acid to a glycidyl group in a hydroxyl group-containing acrylic resin obtained by polymerizing a polymerizable monomer component containing
a) and an alkyl (meth) acrylic acid monoester (having 4 or more carbon atoms), a hydroxyl-containing polymerizable monomer, and a polymerizable monomer component containing an α, β-ethylenically unsaturated acid. Acrylic resin (4) in which a glycidyl ester of (meth) acrylic acid is added to the carboxyl group of the resulting hydroxyl-containing acrylic resin to introduce a polymerizable unsaturated bond
b). In general, the amount of polymerizable unsaturated bonds in the resins (4a) and (4b) is preferably in the range of 0.2 to 1.2 on average per molecule.

5) An alkyl etherified melamine resin having a high mineral spirit tolerance.

6) An oil-modified alkyd resin having an oil length of 15% by weight or more, and a carboxyl group in the alkyd resin containing (meth)
An alkyd resin to which a polymerizable unsaturated bond is introduced by adding a glycidyl ester of acrylic acid. Here, it is preferable that the polymerizable unsaturated bond is introduced in the range of 0.2 to 1.2 on average in the molecule.

7) An equimolar reactant of a polyisocyanate and a hydroxyl-containing polymerizable monomer is urethanized to hydroxyl groups in an oil-modified alkyd resin having an oil length of 15% by weight or more to form a polymerizable unsaturated bond. Alkyd resin introduced. Here, it is preferable that the polymerizable unsaturated bond is introduced in a range of 0.2 to 1.2 on average in the molecule.

8) A polymerizable unsaturated bond obtained by subjecting a hydroxyl group of cellulose acetate butyrate to a urethane reaction with a monomer having a polymerizable unsaturated bond such as isocyanate ethyl acrylate and the like. Cellulose acetate butyrate having the formula: Here, it is preferable that the polymerizable unsaturated bond is introduced in a range of 0.2 to 1.2 on average in the molecule.

In these dispersion stabilizers, a glycidyl ester of (meth) acrylic acid, a polymerizable monomer, α, β
An ethylenically unsaturated acid, an alkyl (C4 or more) monoester of (meth) acrylic acid, a _C2-8 hydroxyalkyl ester of a hydroxyl group-containing polymerizable monomer (meth) acrylic acid, etc. One or more selected from those exemplified as other monomers described as being copolymerized with the contained polymerizable unsaturated monomer can be used.

The above-mentioned various dispersion stabilizers are generally used in an amount of about 10%.
It preferably has a weight average molecular weight in the range of from about 00 to about 50,000, especially from about 3000 to about 20,000.

Among these dispersion stabilizers, the acrylic resin-based compounds exemplified in the above 3) and 4), which are easily dissolved in low-polarity organic solvents such as aliphatic hydrocarbons and have excellent weather resistance, etc. Etc. are particularly preferred. Among them, an acrylic resin-based dispersion stabilizer having a polymerizable unsaturated bond is particularly preferable because the stability of a dispersion is improved by graft polymerization with polymer particles. Among them, n-butyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, lauryl methacrylate, a low-polar monomer such as alkyl esyl having 4 or more carbon atoms of methacrylic acid such as stearyl methacrylate as a main component, If necessary, styrene, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, (meth) acrylic acid, glycidyl (meth) acrylate, 2-hydroxy (meth) acrylate A polymer (dispersion stabilizer) prepared by using ethyl and the like in combination is preferable. Further, there is also a polymer in which glycidyl (meth) acrylate, (meth) acrylic acid, isocyanateethyl methacrylate, or the like is added to the polymer to introduce a polymerizable double bond.

Further, a phosphate group-containing non-aqueous dispersion (P-2)
The organic solvent used in the preparation of the polymer solvent is one that can dissolve the polymer dispersion stabilizer and disperse the polymer particles without substantially dissolving the polymer particles, and particularly those having a boiling point of about 150 ° C. or less. preferable. Specific examples include the following, which can be used alone or in combination of two or more.

Hydrocarbons such as heptane, octane, toluene, xylene and mineral spirit; esters such as ethyl acetate, n-butyl acetate, isobutyl acetate, methyl cellosolve acetate, butyl carbitol acetate, methyl ethyl ketone, methyl isobutyl Ketones, such as ketones and diisobutyl ketone; methanol,
Ethanol, isopropanol, n-butanol, se
alcohols such as c-butanol; ethers such as n-butyl ether, dioxane, ethylene glycol monomethyl ether and ethylene glycol monoethyl ether;
Tell system: "Swazol 310", "Swazol 100"
0 "and" Swazol 1500 "(both are trade names of Cosmo Oil Co., Ltd., petroleum-based aromatic hydrocarbon solvents) and the like.

The phosphate group-containing non-aqueous dispersion (P-2) is prepared, for example, by uniformly dissolving the above-mentioned polymer dispersion stabilizer in an organic solvent, and then adding the phosphate group-containing polymerizable unsaturated monomer. It can be prepared by dispersion polymerization of the contained monomer component.

The monomer component before the dispersion polymerization is easily dissolved in the organic solvent solution of the polymer dispersion stabilizer, but the polymer particles formed after the dispersion polymerization are not substantially dissolved in the solution. is important. The non-aqueous dispersion thus obtained (P
In -2), the polymer derived from the monomer component containing the phosphoric acid group-containing polymerizable unsaturated monomer is dispersed in the form of particles in an organic solvent solution containing a polymer dispersion stabilizer. .
The average particle size of the dispersed polymer particles is preferably in the range of 0.01 to 1 μm.

The dispersion polymerization of a monomer component containing a polymerizable unsaturated monomer containing a phosphoric acid group in an organic solvent solution of a polymer dispersion stabilizer can be easily carried out by a conventionally known radical polymerization method or the like. Can be. The composition ratio of these components in the polymerization reaction is not particularly limited, for example, the ratio of the polymer dispersion stabilizer and the monomer component, based on the total solid weight of both components, the polymer dispersion stabilizer Is 0.1 ~
70%, especially 5 to 50%, the monomer component is 99.9 to 30
%, Especially in the range of 95 to 50%. Further, based on the total solid weight of the polymer dispersion stabilizer and the monomer component, the organic solvent is 95 to 40%, and the total solid content of the polymer dispersion stabilizer and the monomer component is 5 to 60%. Is suitably within the range.

When a crosslinkable functional group such as a hydroxyl group is present in the molecule of the polymer dispersion stabilizer and / or the polymer particles, a melamine resin or a urea resin is added to the phosphate group-containing non-aqueous dispersion (P-2). By blending a polyisocyanate compound which may be blocked or the like as a crosslinking agent, a three-dimensionally crosslinked coating film can be formed.

In the monomer component for preparing the polymer particles, other polymerizable monomers that can be used together with the phosphoric acid group-containing polymerizable unsaturated monomer include, for example, divinylbenzene and ethylene glycol. Alternatively, polymer particles can be obtained by using a monomer having two or more polymerizable unsaturated bonds in one molecule, such as a diester of (meth) acrylic acid with a glycol such as propylene glycol. It is also possible to crosslink inside. In addition, as a method of cross-linking within the particles, it is also prepared by performing dispersion polymerization using a monomer having a self-crosslinking reactive functional group such as N-alkoxymethylated acrylamide or γ-methacryloxy trialkoxysilane. be able to.

The (P-2) may include, if necessary, organic solvents such as hydrocarbons, esters, alcohols, ketones and ethers which are used in the field of paints. It can be further blended.

In the base paint (A), it is also possible to use the above-mentioned resin composition for paint and a resin composition containing a phosphate group such as (P-1) and / or (P-2) in combination. .

The base paint (A) is a paint containing the above resin composition for a paint, and if necessary, further contains other polymer particles, coloring pigments, extender pigments, curing catalysts, flow regulators, pigments. A dispersant, a silane coupling agent, and the like can be appropriately compounded.

In the method 1 of the present invention, the base paint (A)
Is a mixture of the above components and is separated from the dispersion liquid (B).
Is preferably adjusted to 12 to 20 seconds.

The dispersion liquid (B) obtained by dispersing the leafing aluminum flakes in an organic solvent is to be mixed with the base coating material (A) immediately before coating and applied to the object to be coated. -A dispersion obtained by dispersing fing aluminum in an organic solvent.

The leafing aluminum is, for example, one in which a low surface tension component such as stearic acid is present at the time of mechanical pulverization of aluminum and the surface of the flake is coated with these low surface tension components. The size is suitably 2 to 50 μm in the longitudinal direction and 0.1 to 2 μm in thickness.

The organic solvent used in the dispersion liquid (B) is not particularly limited as long as it does not inhibit the reefing effect, but it has a surface tension of at least 27 dyn / cm, especially 30 dyn / cm. It is preferable to contain the above organic solvent, and as a solvent having a surface tension in this range, for example, a hydrocarbon-based solvent such as xylene, toluene, tetralin, solvent naphtha, or mineral spirit;
Ester solvents such as cellosolve and butyl cellosolve; ketones such as cycloheptanone and cyclohexanone; and the like. Of these, hydrocarbon-based, ketone-based and ester-based solvents are particularly preferred from the viewpoint of storage stability. Alcohol solvents or acidic or basic solvents may hinder the reefing effect.

The organic solvent used in the dispersion liquid (B) may be composed of only an organic solvent having a surface tension in the above range, or may be a mixed system with another organic solvent. Is 50% by weight or more, especially 60% by weight,
As described above, the surface tension is preferably 27 dyn / cm or more, particularly preferably 30 dyn / cm or more.

The ratio of the leafing aluminum to the organic solvent in the dispersion (B) is, for example, 1 to 10% by weight, particularly 3 to 7% by weight, and the latter is based on the total amount of these two components. 99-90% by weight, especially 97-93% by weight is preferred.

The dispersion (B) can be prepared by mixing and dispersing leafing aluminum in an organic solvent, and may further contain an anti-settling agent, an ultraviolet absorber and the like, if necessary. It is. Further, when a resin for paint is blended, it is possible to prevent sedimentation of the leafing aluminum. However, in order not to lower the leafing property, for example, an alkyd resin having an acid value of 5 mg KOH / g or less, an acrylic resin, a cellulose resin, or the like. -Suacetate resin, etc.
It can be blended at a ratio of 100 parts by weight or less, particularly 30 parts by weight or less, per 100 parts by weight of the leafing aluminum.

In the method 1 of the present invention, the dispersion (B) is a mixture of the above components and is separated from the base paint (A). ° C
Is preferably adjusted to 10 to 15 seconds.

In the method 1 of the present invention, the base paint (A)
The dispersion (B) is separated in advance, the two components are mixed immediately before coating, and the mixture is applied to the object to be coated. As an object to be coated, for example, a metal or plastic substrate such as an automobile outer panel portion, or an undercoat paint (for example, a cationic electrodeposition paint) is applied to these substrates,
After heat-curing, an intermediate coating material is applied as needed, and a metal- or plastic-coated material which is appropriately heat-cured is exemplified. Among these, it is effective to mix the base paint (A) and the dispersion (B) immediately before coating without curing the intermediate coating film, and to shorten the process, which is effective.

In the method 1 of the present invention, the base paint (A)
And the dispersion (B) are mixed immediately before coating, for example,
Based on the time when these two components are mixed, it is preferable to apply the coating within one hour, preferably from 0 second to 5 minutes, and if it is within these hours, the reefing property does not decrease.

As a specific example of a method of mixing the base paint (A) and the dispersion liquid (B) immediately before coating, and a specific example of the coating method, the following method can be mentioned.

A) After mixing the two components with an ordinary stirrer or the like, the mixture is pressure-fed to a coating machine such as an air spray, an airless spray or an electrostatic coating to perform coating.

B) The two components are separately fed under pressure to a gun tip such as an air spray or an airless spray, mixed inside the gun tip, sprayed, and coated.

C) The two components are separately pumped to a two-head gun type spray having two nozzles, and the two components are separately sprayed from each nozzle. The two components are mixed during the spraying. , Is applied to the object to be coated.

The mixing ratio between the base paint (A) and the dispersion (B) is based on the total solid content of both components, and the base paint (A) is 30 to 80% by weight, particularly 40 to 60% by weight. % By weight, the dispersion (B) is 70 to 20% by weight, particularly 60 to 40% by weight.
Is suitable.

The coating film thickness of the coating material obtained by mixing the base coating material (A) and the dispersion liquid (B) is 10 to 25 μm for the cured coating film.
m, particularly preferably in the range of 13 to 20 μm.

In the method 1 of the present invention, the base paint (A)
And a coating film obtained by applying a coating material obtained by mixing the dispersion liquid (B) with the coating liquid. The coating film can be cross-linked and cured at room temperature or by heating, depending on the selection of a crosslinking agent.
It is suitable to carry out at 60 ° C. for 10 to 40 minutes.

The method 1 of the present invention obtained by mixing the base paint (A) and the dispersion (B) immediately before coating and coating the mixture.
Is a mixed system of a resin composition for coating and leafing aluminum, and the above a) and b)
In any of the coating methods (a) and (c), the leafing aluminum floats on the surface layer of the coating film and is oriented substantially in a single layer parallel to the coating surface. Diffusion distribution inside the coating. Therefore,
Despite being a mixed coating of the coating resin composition and the leafing aluminum, the method is equivalent to or more than the method of applying the leafing aluminum dispersion over the uncured coating surface of the coating resin composition. A coating film having excellent design properties in the form of chrome plating is obtained, and since the leafing aluminum is not laminated, the cohesive failure resistance and adhesion are excellent. Further, the base paint (A) and the dispersion (B) do not separate and come into contact with each other until immediately before coating, so that the leafing properties of the leafing aluminum are deactivated in the base paint (A). Even if a component to be included is included, the design of the resulting coating film is not reduced.

Method 2 of the Invention: Organic solvent-based base coating composition (A) containing a coating resin composition, and
A metallic coating film formed by separating a dispersion liquid (B) obtained by dispersing fing aluminum in advance, mixing the components (A) and (B) immediately before coating, and coating the mixture on the surface to be coated. After curing (Method 1 of the present invention) at room temperature or by heating, a metallic coating film forming method is characterized in that a colorless transparent or colored transparent top coat (C) is applied to the metallic coating surface. Particularly, the top coat (C) preferably contains a phosphate group-containing resin composition.

In the method 2 of the present invention, an organic solvent-based base coating composition (A) containing a coating resin composition and an organic solvent dispersion of leafing aluminum flakes (B) were previously separated. Just mix the two components just before painting,
Until it is applied to the surface to be coated and cured to form a metallic coating film, it can be carried out according to the above-mentioned method 1 of the present invention.

That is, the method 2 of the present invention is characterized in that the top coat (C) is applied to the cured coating surface of the metallic coating film formed by the method 1 of the present invention.

The topcoat paint (C) is a paint to be applied to the cured coating surface of the metallic coating film formed by the method 1 of the present invention. The topcoat paint (C) contains a coating resin composition and an organic solvent. It is a liquid paint which forms a colorless or colored transparent coating film, which contains a bright pigment, an interference pigment or an ultraviolet absorber.

The resin composition for coating in the top coat (C) comprises a base resin and a cross-linking agent, and a cross-linking curable resin composition generally used in the field of coating can be applied.

As the base resin, for example, an acrylic resin, a polyester resin, an alkyd resin, a fluororesin, a urethane resin, a silicon-containing resin containing a crosslinkable functional group such as a hydroxyl group, a carboxyl group, a silanol group, an epoxy group, etc. And especially preferred are acrylic resins containing these crosslinkable functional groups. Examples of the crosslinking agent include melamine resins, urea resins, (block) polyisocyanate compounds, epoxy compounds, carboxyl group-containing compounds, acid anhydrides, and alkoxysilane group-containing compounds that react with these functional groups. In particular, as the melamine resin, a part or all of the methylol group of methylolated melamine is etherified with a monovalent alcohol having 1 to 8 carbon atoms or a fluorinated melamine resin, Moreover, it is preferable to use one having 1 to 5 triazine nuclei. Imino group-containing melamine resins can also be used.

The ratio of the base resin to the crosslinking agent is 50 to 90% by weight, especially 65 to 80% by weight, the latter is 50 to 10% by weight, based on the total solid content of both components.
Particularly, 45 to 20% by weight is suitable.

As the organic solvent, those generally used in the field of paints can be used, and examples thereof include hydrocarbons, esters, alcohols, ketones and ethers.

Further, as the top coat (C) of the method 2 of the present invention, the “phosphoric acid group-containing resin composition” is used in place of or mixed with the above-mentioned resin composition for a paint, whereby the surface to be coated ( This is more preferable because the adhesion to the leafing aluminum floating on the surface layer of the (metallic coating film) is improved.

The "phosphoric acid group-containing resin composition" includes the following (P-1) and (P-2) exemplified for the coating resin composition of the base coating (A) of the method 1 of the present invention. can give.

(P-1): A phosphate group-containing unsaturated monomer and a hydroxyl group-containing unsaturated monomer were used as constituents.
A polymer containing a phosphoric acid group and a hydroxyl group in one molecule.

(P-2): Polymer particles are dispersed in an organic solvent solution of a polymer dispersion stabilizer, and the polymer particles are
A phosphate group-containing non-aqueous dispersion, which is a polymer particle containing a phosphate group-containing unsaturated monomer unit as a constituent.

In the top coat (C), the constituent ratio of both components in a system in which the above-mentioned resin composition for a paint and the resin composition containing a phosphate group are used in combination can be arbitrarily selected according to the purpose. However, generally, the former is 99.09 to 0% by weight, preferably 9 to 9% by weight, based on the total resin solid content of the two compositions.
8 to 50% by weight, more preferably 90 to 70% by weight,
In particular, 85 to 80% by weight, the latter being 0.01 to 100% by weight, preferably 2 to 50% by weight, more preferably 10 to 50% by weight.
-30% by weight, especially 15-20% by weight, are suitable.

As the coloring pigment, glittering pigment and interference pigment used as necessary in the topcoat paint (C), there may be mentioned ordinary paint pigments, for example, titanium oxide, zinc white,
Inorganic pigments such as carbon black, cadmium red, molybdenum red, chrome ero, chromium oxide, prussian bull, and cobalt bull; Organic pigment; scaly aluminum (leafing type, non-leafing type),
Mica, mica surface-coated with a metal oxide, mica-like iron oxide and the like are included.

The amount of each of these pigments in the top coat (C) is such that the cured coating film of the top coat (C) can be passed through and the metallic coating surface of the lower layer by the method 1 of the present invention can be visually recognized. It may be less than the degree of coloring.

The solid content concentration of the top coat (C) at the time of coating was adjusted to about 10 to about 80% by weight, and the cured coating surface of the metallic coating film formed by the method 1 of the present invention was applied by an electrostatic method or a spray method. Depending on the method, the film thickness based on the cured coating film is 1 to 100
μm, preferably about 15 to 60 μm, and then the coating is cured by heating at 100 to 180 ° C. for 10 to 40 minutes, whereby the method 2 of the present invention can be achieved.

Method 3 of the present invention: After the metallic coating film obtained by the method 1 of the present invention is heat-cured, a colorless transparent or colored transparent top coat (C) containing a phosphate group-containing resin composition is applied. This is a method for forming a metallic coating film, which comprises applying a transparent top coat (D).

In the method 3 of the present invention, a transparent top coat (D) is applied to the coated surface of the top coat (C) in the method 2 of the present invention. In particular, the top coat (C) contains a phosphate group. Contains a resin composition.

That is, the method 3 of the present invention provides an organic solvent-based base paint (A) containing a resin composition for a paint and a resin.
Fing aluminum flake organic solvent dispersion (B)
Is separated in advance, the two components are mixed immediately before coating, and the metallic coating film formed by coating on the surface to be coated (the above-described method 1 of the present invention) is cured. After the top coat (C) containing the group-containing resin composition has been applied and cured or left uncured, a colorless or colored transparent top coat (D) is applied to the coated surface of the top coat (C). ) Is applied to form a metallic coating film.

The top coat (D) is a paint that forms a colorless transparent or colored transparent coat to be applied to the cured or uncured coating surface of the top coat (C).

The topcoat paint (D) is a liquid paint containing a base resin and a crosslinking agent and, if necessary, mixed with a coloring pigment, a brilliant pigment, an interference pigment or an ultraviolet absorber. A transparent coating film is formed through the coating film of the paint (D) and the coating film of the top coating material (C) to such an extent that the lower metallic coating film can be seen through.

As the base resin that can be blended with the topcoat paint (D), ordinary paint resins can be used. For example, acrylic resins containing a crosslinkable functional group such as a hydroxyl group, a carboxyl group, a silanol group, or an epoxy group can be used. And resins such as polyester resins, alkyd resins, fluororesins, urethane resins, and silicon-containing resins. In particular, acrylic resins containing these crosslinkable functional groups are preferred. Further, as a crosslinking agent, a melamine resin, a urea resin, a (block) polyisocyanate compound, an epoxy compound, a carboxyl group-containing compound, an acid anhydride, an alkoxysilane group-containing compound, etc., which reacts with a crosslinkable functional group of the base resin. I can give it. Among them, melamine resin, methylo-
Part or all of the methylol group of melamine melamine is a portion obtained by etherification with a monovalent alcohol having 1 to 8 carbon atoms or a fluorinated melamine resin, and has 1 to 5 triazine nuclei. Are preferred. Imino group-containing melamine resins can also be used. The ratio of the base resin to the crosslinking agent is 50 to 50% based on the total solid content of both components.
90% by weight, especially 65-80% by weight, the latter being 50-10%
% By weight, especially 45 to 20% by weight, are suitable.

The overcoating paint (D) includes the “phosphate-containing resin composition” represented by the above (P-1) and (P-2).
Is not substantially contained.

In the method 3 of the present invention, the cured or uncured surface of the topcoat paint (C) is coated with a solid content concentration of about 3
The top coat (D) adjusted to 0 to about 80% by weight is coated with a cured film having a thickness of 5 by an electrostatic method or a spray method.
塗装 100 μm, preferably about 20-80 μm, and then heated at 100-180 ° C. for 10-40 minutes, together with the top coat (C) or only the top coat (D) By curing the above, the coating method of the present invention is achieved.

[0112]

According to the present invention, the following effects can be obtained.

(1) An organic solvent-based base coating composition (A) containing a coating resin composition and an organic solvent dispersion of leafing aluminum flakes (B) are separated in advance and immediately before coating. By mixing, the reefing property during storage or circulation in a one-pack type coating material was not reduced.

(2) In a metallic coating film formed by a mixture of the base coating material (A) and the dispersion liquid (B),
Cohesive failure resistance was improved without lowering the effect of having a dense coating surface, a strong glittering effect, and a finish in a chrome plating tone.

(3) By adding a phosphate group-containing resin composition as the coating resin composition for the base coating composition (A), the metallic coating film obtained and the upper coating layer (C) for the adjacent upper layer are obtained. The adhesion between layers with the transparent coating film was improved.

(4) The multi-layer coating film has better heat insulating properties than other coating films, and the temperature inside the automobile is hardly affected by the state of the outside air.

(5) Since the surface of the leafing type aluminum flake is covered with stearic acid or the like and has a low surface tension, when a clear paint is applied to such a coated surface, the wettability may decrease. In the invention coating method, since the top coat (C) containing the phosphate group-containing resin composition was applied, wettability was improved.

(6) Since the coating films of the top coat (D) and the top coat (C) are separated, any paint can be used as the top coat (D) according to the purpose.

Examples and comparative examples according to the present invention will be described below.

[0120] 1. Specimen 1) Coating object Thermosetting epoxy resin-based cationic electrodeposition paint (“ELECRON 9600” manufactured by Kansai Paint Co., Ltd., trade name) is cured on a 0.8 mm thick dull steel plate that has been subjected to zinc phosphate conversion treatment. Electrodeposit so that the film thickness is about 20 μm.
After heating and curing for 0 minutes, the intermediate coating for automotive coatings (thermosetting polyester resin / melamine resin organic solvent system "TP-37 Primer Surfacer" manufactured by Kansai Paint Co., Ltd., trade name) is cured. Air-spray coating was performed so that the film thickness became about 25 μm, and the coating was left at room temperature for 3 minutes to obtain an object to be tested.

2) Base coating (A) (A-1): 65 parts by weight of a polyester resin (* 1), 35 parts by weight of a butyl etherified melamine resin (* 2), and contains a phosphate group and a hydroxyl group. 10 parts by weight of the resin (* 3) was mixed and dispersed in an organic solvent (xylene / toluene = 1/1 weight ratio), and the viscosity was adjusted to 13 seconds with a forecup # 4.

(* 1) Polyester resin: a phthalic anhydride / hexahydrophthalic anhydride-based polyester resin having a number average molecular weight of about 3500 and a hydroxyl value of 82 mg KOH
/ G, acid value 8 mgKOH / g.

(* 2) butyl etherified melamine resin:
Euvan 28-60 (trade name, manufactured by Mitsui Toatsu Co., Ltd.) (* 3) Resin containing phosphate group and hydroxyl group: 5 parts by weight of acid phosphooxyethyl methacrylate, 2-hydroxyethyl methacrylate 15 parts by weight, 15 parts by weight of N-butoxymethylacrylamide, 20 parts by weight of styrene, 15 parts by weight of butyl methacrylate and 30 parts by weight of 2-ethylhexyl methacrylate in a mixed solvent of an equal weight of xylene and butanol. Resin containing a phosphoric acid group, hydroxyl group and alkoxymethylamide group (acid value based on phosphoric acid group: 21 mgKOH / g, hydroxyl value: 72 mgK)
OH / g, number average molecular weight 11,000) was mixed with an organic solvent (xylene).

(A-2): polyester resin (* 1) 6
5 parts by weight, butyl etherified melamine resin (* 2) 35
Non-aqueous dispersion containing a part by weight and a phosphate group (a) (* 4) 1
0 parts (solid content), 1 part of Tinuvin 900 (manufactured by Ciba Geigy, trade name, ultraviolet absorber), and 0.1 part of "BYK300" (manufactured by Big Chem, trade name, surface conditioner) were added to "Swazo-
And the viscosity was adjusted to 13 seconds / ford cup # 4/20 ° C.

(* 4) Non-aqueous dispersion containing phosphoric acid group (a):
A normal reaction vessel for producing an acrylic resin equipped with a stirrer, a thermometer and a reflux condenser was charged with 120 parts of xylene, 64 parts of heptane and 55 parts of dispersion stabilizer a) (* 5), and heated and stirred at 100 ° C. The monomer and dispersion stabilizer a)
The following mixture consisting of was added dropwise over 5 hours.

Methyl methacrylate 55 parts Methyl acrylate 10 parts 2-hydroxyethyl acrylate 20 parts (2-methacryloyloxyethyl) acid phosphate 15 parts Dispersion stabilizer a) 55 parts α, α ' 1 part of azobisisobutyronitrile After completion of dropping of the above mixture, the mixture was further kept at 100 ° C. for 30 minutes, and then a mixture of 0.5 part of azobisdimethylvaleronitrile and 20 parts of xylene was taken for 1 hour. It was dropped. Thereafter, the mixture was stirred for 2 hours while being kept at 100 ° C., and then cooled to obtain a phosphate group-containing non-aqueous dispersion (a). The solid content was 45%, the acid value was 70, and the particle size of the phosphoric acid group-containing polymer particles was 300 nm.

(* 5) Dispersion stabilizer a): 52 parts of xylene and 10 parts of n-butanol were charged into a usual reaction vessel for acrylic resin production equipped with a stirrer, a thermometer, a reflux condenser and the like. After heating and stirring to reach 125 ° C., the following monomer mixture was added dropwise over 4 hours.

Styrene 20 parts n-butyl acrylate 17 parts 2-ethylhexyl methacrylate 47 parts 2-hydroxyethyl acrylate 10 parts methacrylic acid 6 parts α, α'-azobisisobutyronitrile 3 parts After dropping the monomer mixture, the mixture was further heated at 125 ° C. for 30 minutes.
After holding for 1 minute, a mixture of 0.5 parts of azobisdimethylvaleronitrile and 5 parts of xylene was added dropwise over 1 hour. Thereafter, stirring was performed for 3 hours while maintaining the temperature at 125 ° C. The solids content of the resin solution thus obtained is 60
%, And the acid value was 86.5. 1.2 parts of glycidyl methacrylate was added to this resin solution, and an addition reaction was performed at 120 ° C. until the acid value reached 83 to obtain a dispersion stabilizer a). It had a weight average molecular weight of 12,000, a hydroxyl value of 48, an acid value of 83, and a solid content of 60%.

(A-3): polyester resin (* 1) 6
5 parts by weight, butyl etherified melamine resin (* 2) 35
Non-aqueous dispersion (b) (part by weight and phosphoric acid group) (* 6) 1
0 parts (solid content), 1 part of Tinuvin 900 (manufactured by Cibagaogi, trade name, ultraviolet absorber), and 0.1 part of "BYK300" (manufactured by Big Chem, trade name, surface conditioner) were added to "Swazo-
And the viscosity was adjusted to 13 seconds / ford cup # 4/20 ° C.

(* 6) Non-aqueous dispersion containing phosphoric acid group (b):
A normal reaction vessel for producing an acrylic resin equipped with a stirrer, a thermometer and a reflux condenser was charged with 120 parts of xylene, 64 parts of heptane and 55 parts of a dispersion stabilizer b) (* 7), and heated and stirred to 100 ° C. The monomer and dispersion stabilizer b)
The following mixture consisting of was added dropwise over 5 hours.

Methyl methacrylate 53 parts Glycidyl methacrylate 2 parts Methyl acrylate 10 parts 2-hydroxyethyl acrylate 20 parts (2-methacryloyloxyethyl) acid phosphate 15 parts Dispersion stabilizer b 55 parts) α, α′-azobisisobutyronitrile 1 part After the above mixture is added dropwise, the mixture is further kept at 100 ° C. for 30 minutes, and then a mixture of 0.5 parts of azobisdimethylvaleronitrile and 20 parts of xylene Was added dropwise over 1 hour. Then, after stirring for 2 hours while maintaining the temperature at 100 ° C., the mixture was cooled to obtain a phosphate group-containing non-aqueous dispersion (b) containing polymer particles crosslinked in the particles. The solid content was 45%, the acid value was 44, and the particle size of the phosphoric acid group-containing polymer particles was 250 nm.

(* 7) Dispersion stabilizer b): 52 parts of xylene and 10 parts of n-butanol were charged into a usual reaction vessel for acrylic resin production equipped with a stirrer, thermometer, reflux condenser and the like. After heating and stirring to reach 125 ° C., the following monomer mixture was added dropwise over 4 hours.

Methyl methacrylate 30 parts n-butyl acrylate 15 parts 2-ethylhexyl methacrylate 47 parts 2-hydroxyethyl methacrylate 15 parts Methacrylic acid 3 parts α, α'-azobisisobutyro Nitrile 3 parts After dropping of the above monomer mixture, 30 minutes at 125 ° C.
After holding for 1 minute, a mixture of 0.5 parts of azobisdimethylvaleronitrile and 5 parts of xylene was added dropwise over 1 hour. Thereafter, stirring was performed for 3 hours while maintaining the temperature at 125 ° C. The solids content of the resin solution thus obtained is 60
% And the acid value was 19.2. 1.2 parts of glycidyl methacrylate was added to this resin solution, and an addition reaction was performed at 120 ° C. until the acid value reached 16, to obtain a dispersion stabilizer b.
It has a weight average molecular weight of 12000 and a hydroxyl value of 6
4, the acid value was 16, and the solid content was 60%.

3) Leafed aluminum organic solvent dispersion (B) (B-1): Leafed aluminum flake (*)
8) Dispersion of 5 parts and 95 parts of organic solvent (* 9).

(* 8) Leafing aluminum frame
C: "0620MS" manufactured by Toyo Aluminum Co., Ltd.
A paste having a longitudinal dimension of 13.6 μm, a thickness of 0.4 μm, and a mineral spirit content of 32%.

(* 9) Organic solvent: toluene (surface tension: 30.9 dyn / cm) and m-xylene (surface tension: 3
1.23 dyn / cm).

(B-2): A mixture of 3 parts of leafing aluminum flakes (* 10) and 97 parts of an organic solvent (* 9).

(* 10) Leafing aluminum flake: "High Print 60T" manufactured by Toyo Aluminum Co., Ltd.
Product name, longitudinal dimension 4.4 μm, thickness 0.2 μm, paste containing 32% mineral spirits.

4) Top coat (C) (C-1): Hydroxyl group-containing acrylic resin (* 11) 75
Part, butyl etherified melamine resin (* 2) 25 parts, phosphate group-containing non-aqueous dispersion (a) (* 4) 15 parts (solid content)
Was mixed and dispersed in "Swazol 1000" to adjust the viscosity to 16 seconds / ford cup # 4/20 ° C.

(* 11) Hydroxyl group-containing acrylic resin: methyl methacrylate 38%, ethyl acrylate 17%, n-
A polymer comprising 17% of butyl acrylate, 7% of hydroxyethyl methacrylate, 20% of lauryl methacrylate and 1% of acrylic acid, having a number average molecular weight of 50,000,
The hydroxyl value was 54 mgKOH / g.

(C-2): A hydroxyl group-containing acrylic resin (*
11) 75 parts, butyl etherified melamine resin (* 2)
25 parts, 15 parts (solid content) of a phosphate group-containing non-aqueous dispersion (b) (* 6) and 1 part of a phthalocyanine-based blue pigment (manufactured by Dainichi Seika Co., Ltd.) were mixed and dispersed in "Swazol 1000". The viscosity was adjusted to 16 seconds / ford cup # 4/20 ° C.

5) Top coat (D) (D-1): Carboxyl group-containing acrylic resin (* 1)
2) 50 parts, epoxy group-containing acrylic resin (* 13) 5
0 parts, Tinuvin 900 (manufactured by Cibagaogi, trade name, ultraviolet absorber), 1 part, an equivalent mixture of tetrabutylammonium bromide and monobutylphosphoric acid, 2 parts, "BYK30
0.1 part of "0" (manufactured by Big Chem, trade name, surface conditioner) was mixed and dispersed in "Swazol 1000" to adjust the viscosity to 24 seconds / Ford cup # 4/20 ° C.

(* 12) Carboxyl group-containing acrylic resin: methanol half ester of maleic anhydride 2
0%, 4-hydroxy n-butyl acrylate 20%, n
Polymer comprising 40% of butyl acrylate and 20% of styrene, having a number average molecular weight of 3,500 and an acid value of 86 m
gKOH / g and a hydroxyl value of 78 mgKOH / g.

(* 13) Acrylic resin containing epoxy group:
Glycidyl methacrylate 30%, 4-hydroxy n-butyl acrylate 20%, n-butyl acrylate 30
% And styrene 20%, a number average molecular weight of 3000, an epoxy group content of 2.12 mmol /
g, and the hydroxyl value was 78 mgKOH / g.

[0145] 2. Examples and Comparative Examples A coated steel plate (substrate) coated with an electrodeposition coating and an intermediate coating and heat-cured is vertically fixed at a position 30 cm from the tip of the coating gun, and the coating is performed by moving the conveyor horizontally. Was. A vertical reciprocating AUTO-REA gun (type P901) manufactured by ABB Landsberg Co., Ltd. was used as a coating machine, and two of them were installed horizontally at a distance of 30 cm toward the surface to be coated. The base paint (A) and the dispersion (B) were supplied to these guns by a gear pump using two AC paint pump units manufactured by the company.

The coating of the mixture of the base paint (A) and the dispersion (B) in Table 1 was carried out by the following coating methods a, b and c. The mixing ratio between the base paint (A) and the dispersion (B) is an equal weight ratio in terms of solid content.

Coating method a: The base paint (A) and the dispersion (B) were mixed in advance, and one minute after the mixing, the above apparatus was used, and one AC paint pump unit was used. To supply one coating gun at a rate of 500 ml per minute, and while moving the object to be coated at a rate of 2 m per minute,
Atomizing air pressure 4.0Kg / cm ² , electrostatic applied voltage -60K
Painted with V. The coating thickness is 15 μm for the cured coating.

Coating method b: The base paint (A) and the dispersion (B) were charged into separate AC paint pump units, and the base paint (A) was dispersed at 300 ml / min.
Feeds one paint gun at a rate of 200 ml per minute,
Thereafter, coating was performed in the same manner as in coating method a. The coating thickness is 15 μm for the cured coating.

Coating method c: The base paint (A) and the dispersion (B) were charged into separate AC paint pump units, and the base paint (A) was placed in two AUTO-REA guns installed in parallel. Is supplied to each gun at a rate of 300 ml / min and the dispersion liquid (B) at a rate of 200 ml / min, and while the substrate is moved at a rate of 2 m / min, the atomizing air pressure is 4.0 Kg / min.
cm ² and an applied voltage of −60 KV at the same time, and spraying was performed so that the atomized particles were mixed and applied to the substrate. The coating thickness is 14 μm for the cured coating.

After applying the base paint (A) and the dispersion (B), the coating was left at room temperature for 5 minutes, and then heated at 140 ° C. for 30 minutes to cure the metallic coating. Next,
A top coat (C) is applied to the cured metallic coating surface by air spraying so that the film thickness based on the cured coating film becomes 35 μm, and the coating film is left at room temperature for 7 minutes.
The composition was cured by heating at 140 ° C. for 30 minutes (Method 2 of the present invention).

Further, a top coat (C) was applied to the cured metallic coating surface by air spraying so that the film thickness based on the cured coating film became 20 μm, and the coating film was left at room temperature for 5 minutes. A top coat (D) was applied to the coated surface by air spraying so that the film thickness based on the cured coating film was 30 μm, and the coating film was left at room temperature for 7 minutes.
For 30 minutes to simultaneously cure both coating films (Method 3 of the present invention).

In Comparative Example 1, the base paint (A-1)
And the dispersion (B-2) were mixed at an equal weight ratio in terms of solid content, and the composition was used after standing at room temperature for 24 hours.

Table 1 shows the results of these coating processes and the performance tests of the obtained coating films.

[0154]

[Table 1]

The test method is as follows.

Designability: The result of visual evaluation of the coating film.
○ indicates that it was finished in chrome plating, and X indicates that it was not in chrome plating but finished with a normal metallic feeling. Wettability: The quality of wetness when the composition (C) was spray-coated on the cured metallic coated surface was visually evaluated.は indicates good wetting, Δ indicates poor wetting, and × indicates very poor wetting.

Adhesion: Cut lines were made to reach the base material with a cutter, and 100 goban eyes having a size of 1 × 1 mm were formed. An adhesive cellophane tape was stuck on the surface of the cut lines, followed by rapid peeling. The later coated surface was observed. ○ indicates that no peeling of the painted film was observed at all, and x indicates that 10 or more peeled films of the painted film were observed.

IV value: The Y value at a light receiving angle of 15 degrees was measured using a portable variable angle spectrophotometer “MA68 measuring device” manufactured by X-Rite. This indicates the brightness of the coating film, and indicates the sense of brightness in the highlight portion of the metallic coating film. The larger the value, the better the brightness.

SV value: Using "MA68 measuring instrument",
The Y value at a light receiving angle of 45 degrees was measured. This indicates the brightness of the coating film, and indicates the brightness of the front color of the coating film. This means that the aluminum flakes are oriented horizontally and there is little diffused light.

FF value: Measured using "MA68 measuring instrument". The above IV value and SV value were calculated by applying the formula FF = (IV−SV) / [(IV + SV) / 2]. This indicates the contrast between the brightness of the highlight and the brightness of the front. The larger the value, the stronger the contrast and the chrome plating tone.

Claims (8)

[Claims] 1. An organic solvent-based coating composition (A) containing a coating resin composition and a leafing aluminum frame.
The organic solvent dispersion (B) of
A method for forming a metallic coating, comprising mixing the two components immediately before coating and coating the surface to be coated. 2. The resin composition for coating of the base coating (A) comprises:
The method for forming a metallic coating film according to claim 1, further comprising a phosphate group-containing resin composition. 3. The phosphoric acid group-containing resin composition according to claim 1, wherein the (P-1) a phosphoric acid group-containing unsaturated monomer and a hydroxyl group-containing unsaturated monomer are used as constituents. Or polymer particles dispersed in an organic solvent solution of (P-2) a polymer dispersion stabilizer, wherein the polymer particles comprise a phosphate group-containing unsaturated monomer unit. The method for forming a metallic coating film according to claim 2, which is a non-aqueous dispersion containing a phosphoric acid group, which is a polymer particle contained as a polymer. 4. A resin composition for a base paint (A), comprising:
The method for forming a metallic coating film according to claim 1, further comprising a phosphate group-containing resin composition and a crosslinking agent. 5. The dispersion (B) has an organic solvent having a surface tension of 27.
2. The method for forming a multilayer coating film according to claim 1, wherein the organic solvent contains at least dyn / cm. 6. An organic solvent-based coating composition (A) containing a coating resin composition and a leafing aluminum frame.
The organic solvent dispersion (B) of
Immediately before painting, mix the two components and let them be painted on the surface to be painted.
A method for forming a metallic coating film, which comprises applying a top coat (C) after heat curing. 7. The method according to claim 6, wherein the top coat (C) is a colorless transparent or colored transparent paint containing a phosphate group-containing resin composition. 8. An organic solvent-based coating composition (A) containing a coating resin composition and a leafing aluminum frame.
The organic solvent dispersion (B) of
Immediately before painting, mix the two components and let them be painted on the surface to be painted.
After heat curing, a metallic coating film characterized by applying a top coat (C) of a colorless transparent or colored transparent paint containing a phosphate group-containing resin composition, and then applying a transparent top coat (D). Forming method.