JP2503514B2 - Paint finish method - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention is capable of forming a coating film which is excellent in weather resistance, smoothness, image clarity, and design, and which is finished by a glittering coating film. The present invention relates to a paint finishing method that simplifies the process and is advantageous for resource saving and prevention of suburbs.

2. Description of the Related Art Conventional technology and its problems Conventionally, as a high-quality coating finishing method having a brilliant feeling on automobile outer panels, etc., a metallic coating containing a scaly metallic pigment such as aluminum powder is coated on the intermediate coating surface, and then clear. A metallic finish by a two-coat, one-bake method in which both coating films are heated at the same time after being coated with a coating material is often adopted. However, in the coating film by this method, it is difficult to say that the glittering feeling is sufficient, it is difficult to finish in a deep hue, and the color of the shade surface is darker than that of the front surface, which is preferable in appearance. Absent. Further, the aluminum powder itself is weak against acid and alkali, which causes stains and blisters. As described above, aluminum powder and the like are not sufficient for high-quality finishing on outer panels of automobiles, and have problems such as durability of the coating film.

In order to solve these problems, it has been proposed to use a mica powder coated with a metal oxide such as titanium dioxide instead of the metallic pigment such as aluminum. This pigment is a tabular crystal, and since incident light repeats incidence and reflection between the surface of the pigment and the inner layer,
A pearly luster is obtained, and the finished appearance, hue and the like can be improved as compared with metallic pigments such as aluminum powder. However, the refractive index of the mica forming the central part of this pigment is not much different from that of the paint vehicle component, and most of the incident light is transmitted, so the glittering feeling is inferior to that of aluminum powder, and the design is It is hard to say that it is significantly superior to aluminum powder.

Further, in order to improve the glitter of the coating material using the aluminum powder or mica powder, it has been studied to increase the particle size of these materials. However, if a large particle size is used, the smoothness and sharpness of the coated surface deteriorates, and it is necessary to coat the coated surface with liquid clear coating more than once, which complicates the coating process and prevents pollution. Not preferable from the viewpoint of resource saving.

Further, the mica powder itself is transparent or translucent, so poor in payability, and when a color pigment is co-present in order to impart in payability, the transparency of the coating film is impaired, resulting in sufficient glitter. There is a drawback that it can not be expressed, as a method for solving this, after forming a coating film to which impey power is imparted by a coloring pigment in advance as an intermediate coating film, a paint containing the above-mentioned large particle size powder However, this coating method is not preferable because it complicates the coating process and raises the production cost, and is also not preferable in terms of resource saving and pollution control. In addition, when the above-mentioned topcoat with poor impayability is applied on the conventional electrodeposition coating, if the topcoat is exposed to the outdoor environment for a long period of time, the electrodeposition coating deteriorates and the coating of the topcoat is peeled off. There is a drawback that

Means for Solving Problems The present inventors have solved such problems, simplified the coating process, significantly improved the finish appearance of the coating film, and are extremely advantageous in terms of resource saving and pollution control. In addition, we have conducted intensive research to develop a paint finishing method that is excellent in brilliance.

As a result, a cationic electrodeposition paint having a specific composition with good weather resistance was applied, and then a colored paint was applied to the electrodeposition coated surface, and then the above aluminum powder or mica powder was replaced with titanium dioxide. After applying a paint forming a glitter coating film using an iron oxide pigment as a metallic pigment, by applying a powder clear paint on the coated surface,
It has been found that the above object can be achieved. The present invention has been completed based on these findings.

That is, the present invention is a method of applying (1) electrodeposition coating, (2) coloring coating, (3) pearl pigment-containing coating, and (4) clear coating to finish, wherein the (1) electrodeposition coating is , (A) an epoxy-based cationic electrodeposition resin having a surface tension of 40 to 60 dyne / cm and capable of forming an aqueous bath capable of being electrodeposited on the cathode by neutralizing with an acid, and (B) having a surface tension of A nonionic film forming resin having a density of 25 to 45 dyne / cm is contained at a weight ratio within the range of (A): resin (B) = 60: 40 to 98: 2, and the surface tension of the resin (A). Is a cationic electrodeposition coating composition for forming a multilayer film, which has a surface tension higher than that of the resin (B), and the (2) colored coating composition is a coating film having a thickness of 30μ after curing and having a wavelength of 400 to 700 nm. The above-mentioned (3) pearl pigment-containing paint is a paint having an average transmittance value of 5% or less. A pigment obtained by coating iron oxide particles containing at least 80% of iron oxide crystal particles with titanium dioxide, the longitudinal dimension (average central particle diameter) of which is 5 to 30 μ, and the thickness is 1/10 to the longitudinal direction. 1/20, wherein the pearl pigment is 0.1 to 30 parts by weight per 100 parts by weight of vehicle component (solid content), wherein the clear coating is a powder coating containing no colorant (4). The present invention relates to a paint finishing method characterized in that

The feature of the present invention is to coat a colored paint having good hiding property on the surface of a cationic electrodeposition coating film having a specific composition with good weather resistance and anticorrosion property, and then iron oxide containing at least 80% iron oxide crystal particles. This is where a paint containing a pearl pigment in which particles are coated with titanium dioxide is applied, and then a powder clear paint is applied. As a result, the glittering property is extremely excellent, and the weather resistance, smoothness, feeling of fleshness, color design, etc. are remarkably improved, and a coating finishing method effective for resource saving and pollution prevention is completed.

First, the above-mentioned (1) cationic electrodeposition coating used in the present invention is formed by a single electrodeposition coating to form a lower layer portion (on the surface side of the metal substrate).
It is possible to form a multilayer film having a concentration gradient in which the anticorrosive resin is mainly distributed in (hereinafter the same) and the weather resistant resin is mainly distributed in the upper layer portion. More specifically, the coating material is a binder component prepared by dispersing a nonionic film-forming resin such as an acrylic resin or a polyester resin having excellent weather resistance in an epoxy resin-based cationic electrodeposition resin. It is a cationic electrodeposition paint. The nonionic film-forming resin particles are very stably dispersed by the epoxy resin,
It has excellent storage stability, the epoxy cationic electrodeposition resin and the nonionic film-forming resin are blended in a specific ratio, and the surface tension of these resin components is limited to a specific range, and the former surface Since the tension is set to be higher than that of the latter, the coating film electrodeposited using the cationic electrodeposition bath formed from the nonionic coating film-forming resin in the upper layer part due to the difference in surface tension when baked and dried. On the other hand, the epoxy resin migrates to the surface side of the metal substrate, that is, to the lower layer portion, and as a result, a non-ionic film forming resin occupies the upper layer portion and the epoxy resin occupies the lower layer portion. A multilayer film having is formed. as a result,
A single electrodeposition coating and baking can form a multilayer coating film having excellent corrosion resistance and weather resistance.

Therefore, even if the intermediate coating step is omitted and the top coat film of the above (2) to (4) is directly applied to the bake-cured coat surface of the electrodeposition paint, the weather resistance peeling (light transmitted through the top coat film) Causes the primer to deteriorate due to light, and
The phenomenon of peeling between the primer and the overcoat layer) was never generated. Moreover, since the intermediate coating process is omitted, the coating process is simplified and the coating cost can be reduced.

The cationic electrodeposition coating film of the component (1) used in the present invention has excellent weather resistance. Specifically, the cured coating film of the coating alone is exposed to a light beam of 1100 K.juole / m ² · hr for 40 hours. The retention of 60 degree specular reflectance after irradiation is 50% or more.
It can be over 60%.

Next, since the colored paint of (2) above has good hiding payability and can be adjusted to any color, it is applied to the coated surface (3).
Synergistic with the brilliance of the coating film containing the pearl pigment, the coating film having excellent color and design is formed.

The coating film of the pearl pigment-containing paint of (3) above has a metallic glittering characteristic that is distinctive from any angle when exposed to direct sunlight such as the sun, and has a three-dimensional appearance that appears from the deep part of the coating film. Gives a sense of color. Further, the pearl pigment is
It also has good light resistance, weather resistance, chemical resistance, heat resistance, and adhesion.

Further, in order to sufficiently exhibit the excellent brilliance of the pearl pigment, the coating material containing the pigment has excellent hiding property and has a low lightness obtained by adjusting the Munsell value (lightness) to 0 to 6. It is preferable to apply it to the surface of the colored coating film (corresponding to the coating film surface of the component (2) above). That is, when a pearl pigment-containing paint is applied to the surface of a colored coating film adjusted to have such a low brightness, the glitter characteristic of the pearl pigment can be sufficiently exerted, and for example, the inside of the coating film is studded with diamond. It looks shining brightly. Such finishing properties cannot be expected with aluminum powder or mica powder.

As the above (2) colored paint and (3) pearl pigment-containing paint, an aqueous paint containing water as a main solvent or dispersion medium,
The use of a solvent containing no or almost no organic solvent is extremely advantageous in view of resource saving and pollution control, but a solvent containing no or almost no water may be used.

Further, if these are water-based paints, since they are generally applied with high viscosity, sedimentation of the bright color material during storage is suppressed, and storage stability is extremely good. Generally, it is very difficult to suppress sedimentation of the bright color material for a long period in an organic solvent-based paint which is applied with a low viscosity.

Furthermore, since the powder coating of (4) above applied on the surface of the pearl pigment-containing coating contains no organic solvent at all, it is particularly effective for resource saving and pollution control.
Since it can be easily applied to a thick film of μ or more, even if there are irregularities due to the glittering color material particles on the base coat, the coating that is powder-cleared and heat-cured has no irregularities on its surface. It can be easily finished on a coated surface with an excellent finished appearance such as a feeling of flesh, and a sharpness.

Next, the coating method of the present invention will be described more specifically.

Component (1): (A) Epoxy cationic electrodeposition resin having a surface tension of 40 to 60 dyne / cm and capable of forming an aqueous bath capable of electrodeposition on the cathode by neutralizing with an acid, and (B) A nonionic film-forming resin having a surface tension of 25 to 45 dyne / cm is contained in a resin (A): resin (B) = 60: 40 to 98: 2 solid content weight ratio and the resin ( A cationic electrodeposition coating composition for forming a multilayer film, wherein the surface tension of A) is higher than that of the resin (B).

The epoxy-based cationic electrodeposition resin (component A) is a polyamine resin such as amine-added epoxy resin which has been conventionally used in the field of cationic electrodeposition coatings, for example, polyepoxide and primary mono- and polyamines, secondary polyamines or Adducts with mixed primary and secondary polyamines (see, eg, US Pat. No. 3,984,299); Additions of polyepoxides with secondary mono- and polyamines having ketiminated primary amino groups (eg, US Pat. Fourth 4,017,438
No.); a reaction product obtained by etherification of a polyepoxide and a ketiminized hydroxy compound having a primary amino group (see, for example, JP-A-59-43013). These polyamine resins can be cured with alcohol-blocked polyisocyanate compounds to form electrodeposition coatings.

Further, an amine-added epoxy resin that can be cured without using a blocked isocyanate compound can also be used. For example, a resin obtained by introducing a β-hydroxyalkyl carbamate group into a polyepoxide (see, for example, JP-A-59-155470). ); It is also possible to use a resin of a type that can be cured by a transesterification reaction (see, for example, JP-A-55-80436).

Examples of the polyepoxide used for producing the resin (component A) include polyglycidyl ether of polyphenol which can be produced by reacting porphenol with epichlorohydrin in the presence of alkali. Representative examples are bis (4-hydroxyphenyl) -2,2-propane, bis (4-hydroxyphenyl) -1,1-ethane,
Examples thereof include glycidyl ethers of polyphenols such as bis (4-hydroxyphenyl) -methane, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfone, phenol novolac and cresol novolac, and polymers thereof.

Among the above-mentioned polyepoxides, those having a number average molecular weight of at least about 38 are particularly preferable in terms of price and corrosion resistance.
0, preferably about 800 to 2,000, and an epoxy equivalent of 190 to 2,000, preferably 400 to 1,000, of polyglycidyl ethers of polyphenols. Is a polyepoxide.

The component (1), an epoxy-based cationic electrodeposition resin (component A), has a surface tension of 40 to 60 dyne / cm, preferably 45 to 55 dyn.
It must be within the range of e / cm. Surface tension is 40dy
If it is lower than ne / cm, the compatibility with the nonionic film-forming resin (component B) becomes too good, and it becomes difficult to form a multilayer film having a desired concentration gradient, and the film has weather resistance. , The anticorrosion property tends to be inferior. On the other hand, when the surface tension exceeds 60 dyne / cm, the concentration gradient extremely advances and the resin (component A) and the resin (component B) are completely separated into two layers, and the resin (component A) and The interlayer adhesion of the resin (component B) tends to be poor.

In the present specification, an epoxy cationic resin (component A) and a nonionic film-forming resin (component B) described later
"Surface tension" is measured as follows: A resin (component A) or a resin (component B) is diluted with a solvent and dried on a degreased smooth tin plate with a bar coater to form a dry coating film. Paint to 10 ηm. 1 at room temperature
After air-drying and further drying at 50 ° C / 0.1 atm for 1 hour, the following measurement is performed after 10 minutes at room temperature.

Deionized water is dropped and the contact angle (θ) with the dry resin is measured.

Then, the empirical formula of Sell and Neumann In the formula, γ _L : surface tension of water (72.8 dyne / cm), γ _S : resin (A component) or resin (B component) depending on the surface tension (dyne / cm) of resin (A component) or resin (B component) ) Surface tension.

The nonionic film-forming resin (component B) used as the component (1) may be either a thermosetting resin or a thermoplastic resin as long as it is a resin having particularly excellent weather resistance for the purpose of the present invention. A medium acrylic resin, a polyester resin, a polyester modified resin and a silicone modified resin are preferably used. It is important and essential that this resin (component B) is nonionic, that is, it does not have a functional group that produces a cationic group upon acid neutralization. That is, when the resin (component B) is ionic, its surface tension increases, so that in order to obtain a multilayer coating film having an ideal concentration gradient, which is the object of the present invention, The skeleton (nonionic portion) must be designed to have a small surface tension, and the resulting multilayer coating film tends to have poor interlayer adhesion and corrosion resistance.

Hereinafter, a suitable resin (component B) will be described more specifically.

Examples of the nonionic acrylic resin include methyl (meth) acrylate, ethyl (meth) acrylate,
Alkyl ester of (meth) acrylic acid such as butyl (meth) acrylate, propyl (meth) acrylate and 2-ethylhexyl (meth) acrylate; (meth) acrylic acid such as hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate Acrylic monomers such as hydroxyalkyl ester; glycidyl (meth) acrylate; (meth) acrylic acid; and other unsaturated monomers such as styrene and derivatives (for example, α-methylstyrene), (meth) acrylonitrile, butadiene, etc. One obtained by appropriately selecting one kind or two or more kinds depending on the physical properties and (co) polymerizing it according to a conventional method can be mentioned.

The acrylic resin has a number average molecular weight of about 3,000 to about 100,0.
Suitable values are 00, preferably in the range of about 4,000 to about 50,000. Further, when the acrylic resin contains a hydroxyl group as a functional group, it can be crosslinked and cured by reacting with a polyisocyanate compound which is a crosslinking agent for the resin (component A).

Examples of the nonionic polyester resin used as the resin (component B) include phthalic acid and its acid anhydride,
Isophthalic acid, terephthalic acid, trimellitic acid and its acid anhydride, pyromellitic acid and its acid anhydride, hexahydrophthalic acid and its acid anhydride, succinic acid, adipic acid, pimelic acid, sebacic acid, brassylic acid, etc. Condensate polybasic acid components with polyol components such as ethylene glycol, diethylene glycol, propylene glycol, neopentyl glycol, 1,6-hexanediol, trimethylolpropane, glycerin, pentaerythritol, and tricyclodecane dimethanol according to a conventional method. Those which can be produced by polymerizing are included. At that time, for example, benzoic acid or p-t-butylbenzoic acid may be used as the end-capping agent to control the molecular weight.

As the resin (component B), a blend of the above-mentioned acrylic resin and polyester resin can also be used, and a polyester modified (graft) acrylic resin and an acrylic modified (graft) polyester resin can also be used by combining the above raw materials. They can be synthesized and can also be used as resins (component B) (these are collectively referred to as "polyester-modified resins" in the present specification).

Furthermore, the nonionic silicone-modified resin used as the resin (component B) includes a base resin, for example, the above-mentioned acrylic resin or polyester resin, or an alkyd resin modified with a silicone resin. The amount used is 50% by weight or less, preferably 3 to 45% by weight based on the whole resin. When the content of the silicone resin exceeds 50% by weight, the interlayer adhesion with the top coating film deteriorates. Further, the resin (component A) and the resin (component B) are completely separated into two layers, and the adhesion between the layers tends to deteriorate.

The silicone resin used for modifying the base resin is usually an organoorganic compound having a number average molecular weight of preferably about 500 to about 2,000 and having two or more reactive groups such as a hydroxyl group and an alkoxy group in the molecule. A polysiloxane resin such as Z-6018 (product of Dow Corning, molecular weight 160)
0), Z-6188 (Dow Corning product, molecular weight 650), Sylkyd50, DC-3037 (Dow Corning product), KR
-216, KR-218, KSP-1 [Shin-Etsu Silicone Co., Ltd. product], TSR-160, TSR-165 [Tokyo Shibaura Electric Co., Ltd. product], SH5050, SH6018, SH6188 [Toray Silicone Co., Ltd.]
Products] and the like can be used.

The silicon-modified resin is produced by co-condensing the above-mentioned silicon resin and a base resin having a hydroxyl group and / or a carboxyl group, for example, an acrylic resin, a polyester resin, etc. in the above-mentioned use ratio by a method known per se. You can

The resin (component B) needs to have a surface tension in the range of 25 to 45 dyne / cm, preferably 28 to 40 dyne / cm.
If the surface tension is less than 25 dyne / cm, the interlayer adhesion between the formed coating film and the top coating film will decrease, and the resin (A component) and resin (B component) will be completely separated into two layers and the interlayer adhesion will occur. It also becomes worse. On the other hand, when the surface tension exceeds 45 dyne / cm,
The compatibility with the resin (component A) becomes so good that it becomes difficult to form a multilayer film having a desired concentration gradient, and the weather resistance and corrosion resistance of the coating film are both poor.

In the component (1), the surface tensions of the resin (A component) and the resin (B component) are within the specific ranges, and the surface tension of the resin (A component) is larger than the surface tension of the resin (B component). For example, a multi-layer film having a concentration gradient can be formed, but it is preferable that the resin (component A) and the resin (B
Component) surface tension difference is 5 dyne / cm or more, more preferably
It is easy and rapid to form a multilayer film, and it is practical to select and combine both components so that they fall within the range of 10 to 20 dyne / cm.

Further, in order to further facilitate the formation of the multi-layer film, it is necessary to select a combination in which the compatibility between the resin (component A) and the resin (component B) is incompatible or hardly compatible. Good. When the compatibility between the resin (component A) and the resin (component B) is "incompatible" or "hardly compatible", it means the following. That is, the resin (component A) and the resin (component B) are mixed in an equal weight ratio and then dissolved in an organic solvent or the like,
Air-spray evenly on a Teflon plate to a film thickness of about 70 microns, then bake at a constant temperature between 160-220 ° C and for a fixed time between 15-60 minutes, allow to cool, and obtain When the light transmittance of the isolated film is measured, the light transmittance of ultraviolet rays (wavelength: about 300 mm) and visible rays (wavelength: about 500 mm) show values of 0 to about 70%. Means that.

The component (1) can be prepared by dispersing and / or dissolving the resin (component A) and the resin (component B) described above in water by a method known per se. For example, water and an acid (for example, water-soluble organic acid or inorganic acid such as acetic acid, formic acid, lactic acid, phosphoric acid, sulfuric acid) in a state where the resin (component A) and the resin (component B) are dissolved in a water-miscible organic solvent. ) And neutralize to form an aqueous solution, or
Component) in an aqueous medium and neutralized with an acid to form an aqueous bath, in which the water-miscible organic solvent solution of the resin (component B) is forcibly dispersed using a homogenizer or the like. Can be prepared by any method. In the composition obtained by any of the above-mentioned and methods, the resin (B
The component) particles are extremely stably dispersed in water by the neutralized product of the resin (component A) and exhibit excellent storage stability for a long period of time.

In preparing the component (1), the resin (component A) and the resin (component B) may be used alone or in combination of two or more. The resin (A component) and the resin (B component) are used in a ratio of (A component) :( B component) = 60: 40 to 98: 2, preferably 70:30 to 95: 5. is necessary.

If the blending ratio is outside the above range, a multilayer film having an effective concentration gradient cannot be obtained, resulting in poor weather resistance or corrosion resistance.

To the component (1), in addition to the components (A) and (B) described above, if necessary, a coloring pigment, an anticorrosive pigment, an extender pigment, an additive and the like which are commonly used in the field of coating materials are added. You can also do it.

Further, when an epoxy cationic electrodeposition resin of a type that cures when used in combination with a curing agent is used as the resin (component A), a polyisocyanate compound such as isophorone diisocyanate is used as a curing agent in the composition.
A predetermined amount of a blocked product such as 4,4'-diphenylmethane diisocyanate can be blended.

As the method and apparatus for electrodeposition coating the component (1) on the coating material, known methods and apparatuses conventionally used in cathodic electrodeposition coating can be used. At this time, it is desirable to use the object to be coated as a cathode and the stainless steel or carbon plate as the anode. The electrodeposition coating conditions that can be used are not particularly limited, but generally bath temperature: 20 to 30 ° C., voltage: 100 to 400 V (preferably 200 to 300
V), current density: 0.01 to 3 A / dm ² , energization time: 1 to 5 minutes, pole area ratio (A / C): 2/1 to 1/2, distance between poles: 10 to 100 cm, electricity under stirring condition It is desirable to wear.

The coating film deposited on the object to be coated of the cathode has a film thickness of 10 to 50 μm, especially 20 to 40 μm based on the cured coating film, and after washing the deposited film, the film thickness is about 150 to about 230 ° C. It can be baked and cured for 10 to 30 minutes. By this curing treatment, the epoxy resin (A component) is added to the portion in contact with the metal substrate.
A film-forming resin (component B) on the surface of the primer layer
A multi-layered structure in which is distributed preferentially is formed. It is considered that this is because the two resins act to separate layers in the heated and molten state mainly due to the difference in surface tension.

The fact that the electrodeposition coating film layer thus formed has a multi-layer distribution structure is that the coating film is divided into three layers of an uppermost layer, an intermediate layer and a lowermost layer in the metal substrate direction (thickness direction), This can be confirmed by obtaining the distribution rate (content% by weight) of the resin (component B) in this divided layer. In the electrodeposition primer layer formed from the component (1), the distribution ratio of the resin (component B) is generally 50% or more in the uppermost layer, preferably
70 to 95%, and the distribution ratio of the resin (component B) in the lowermost layer is 10% or less, preferably 5% or less.

(2) Component: wavelength of 400-700nm based on cured coating thickness of 30μ
A colored paint having an average light transmittance of 5% or less.

This is a liquid paint to be applied to the cured coating film surface of (1) above, which is a thermosetting composition containing a base resin, a curing agent and a colorant as main components, and water and / or an organic solvent as a solvent or dispersion medium. It is a paint.

First, the base resin is a main component of the coating film formed by the component (2), and a known coating resin having good weather resistance is preferably used, and examples thereof include acrylic resin, polyester resin, urethane resin and the like. Can be given.

When the component (2) is used as an aqueous system containing water as a main dispersion medium or a solvent, for example, a carboxyl group (—COOH), a hydroxyl group (—OH), a methylol group (—CH ₂ OH) is contained in the base resin. , amino (-NH _2), sulfone group (-SO
It is preferable to introduce hydrophilic functional groups such as ₃ H) and polyoxyethylene-bonded CH ₂ CH ₂ O _n . this house,
Most commonly, it is hydrophilized by introducing a carboxyl group and neutralizing it with an alkaline substance, for example, a neutralizing agent such as sodium hydroxide or various amines. The amount of the carboxyl group introduced for water-solubilization varies depending on the skeleton of the resin and the content of other hydrophilic groups, the type of neutralizing agent, the neutralization equivalent, etc. There
It is preferably 20 or more, and may be less than 20 in an aqueous dispersion.

Further, as a method for water-dispersing the above-mentioned base resin, it can also be obtained by emulsion polymerization in the presence of a surfactant or a water-soluble resin. Further, it can be obtained by dispersing the above resin in water in the presence of an emulsifier or the like. In this water dispersion, the hydrophilic group may not be contained in the base resin at all, or may be contained in a smaller amount than the water-soluble resin.

Among them, an aqueous dispersion of an acrylic resin is a conventionally known one, for example, a nonionic surfactant such as polyoxyethylene nonylphenyl ether, an anionic surfactant such as polyoxyethylene alkylallyl ether sulfate ester salt, and an acid value. Polymerize acrylic monomers and, if necessary, other copolymerizable monomers in the presence of dispersion stabilizers such as water-soluble resins such as acrylic resins having a number average molecular weight of about 5,000 to 30,000 and about 20 to 150. The average particle size prepared by
A water dispersion in the range of about 1.0 μm is preferable.

The acrylic resin dispersion is preferably obtained by a multistage polymerization method. That is, first, a monomer containing no or small amount of α, β-ethylenically unsaturated acid is polymerized, and then a monomer containing a large amount of α, β-ethylenically unsaturated acid is copolymerized. The multi-stage polymerized emulsion obtained by doing so is preferable from the viewpoint of coating workability because it thickens by neutralizing with a neutralizing agent. Ammonia or a water-soluble amino compound is suitable as the neutralizing agent used.

Further, in order to use the component (2) as an organic solvent system,
It is not essential to introduce the hydrophilic group into the base resin, but it is preferable that the base resin has a functional group (for example, a hydroxyl group) capable of undergoing a crosslinking reaction with the curing agent described later. The base resin of can be used.

The curing agent is for three-dimensionally crosslinking and curing the above-mentioned base resin by heating, and specifically, condensation or co-condensation of melamine, benzoguanamine, urea or the like with formaldehyde, or ether with a lower monohydric alcohol. An amino resin obtained by converting into a suitable compound is preferably used. Blocked polyisocyanate compounds can also be used.

Examples of the colorant include inorganic pigments such as titanium dioxide, iron oxide, chromium oxide, lead chromate, carbon black, phthalocyanine blue, phthalocyanine green, carbazole violet, anthrapyrimidine yellow, flavanthron yellow, isoindoline yellow, and indus. Organic pigments such as Ronblue and quinacridone violet can be mentioned. As the component (2), an extender pigment such as talc or kaolin can be used in combination.

The ratio of each of the above components in the component (2) can be arbitrarily adopted according to the purpose. For example, the base resin and the curing agent are:
Based on the total amount of both components, the former is 60 to 90% by weight,
Particularly preferred is 70 to 85% by weight, the latter is 40 to 10% by weight, and particularly 30 to 15% by weight.

The colorants may be blended in an appropriate combination according to the desired color, and the blending amount is such that in a cured coating film having a film thickness of 30μ, the light transmittance at a wavelength of 400 to 700 nm is 5% or less. Range, specifically resin solids (base resin and curing agent)
Although it depends on the colorant, it is suitable to be 1 to 150 parts by weight per 100 parts by weight. When the light transmittance is more than 5%, the hiding property of the coating film is deteriorated and a slight variation in the coating film thickness may cause color unevenness, which is not preferable.

Regarding the light transmittance, the coating composition of the component (2) is applied to the glass plate so that it becomes 30μ based on the cured coating film, and after curing, the coating film is immersed in warm water of 60 to 70 ° C. Peel and dry. Then, it is the spectral transmittance measured at a wavelength of 400 to 700 nm using a self-recording spectrophotometer (EPS-3T type, manufactured by Hitachi, Ltd.) using the coating film as a sample. Wavelength to be measured (400 to 700n
When there was a difference due to m), the maximum value was recorded.

In addition, when the lightness of the colored coating film of the component (2) is 6 or less based on the Munsell value (V), the pearlescent pigment contained in the component (3) below has sufficient glitter. It is more preferable because it can be exhibited.

The component (2) colored paint is coated in a usual manner by adding deionized water and / or an organic solvent, and if necessary, an additive such as a thickener and an antifoaming agent to a solid content of 10 to 40% by weight. %
The viscosity is adjusted to about 800 to 5000 cps / rpm (B type viscometer).
It is applied by spray painting to obtain a cured film thickness of about 50μ.

(3) component: pearl pigment-containing coating (3) The pearl pigment-containing coating is composed of iron oxide particles containing at least 80% of α-iron oxide crystal particles as a luster pigment, coated with titanium dioxide, and Directional dimension (average particle size) is 5 to 30μ, thickness is 1/10 to 1/1 of the longitudinal direction.
It contains 20 pearl pigments, and in principle,
It is a paint that does not contain the colorant described in the component (2).

More specifically, it is a liquid coating material containing the pearl pigment, a base resin and a curing agent as main components, and may be either water-based or organic solvent-based.

Among them, it is preferable to use the base resin and the curing agent selected from those described in the above component (2).

The pearl pigment used in the component (3) is a flat plate (hexagonal plate) containing α-iron oxide (Fe ₂ O ₃ ) crystal particles as a main component.
Is a pigment in which mica-like iron oxide is used as a core and the surface thereof is coated with titanium dioxide. The plate-like micaceous iron oxide forming the core has α-Fe ₂ O ₃ of at least 80% by weight, preferably 9%.
0 wt% or more, more preferably 98 wt% or more, SiO
_It contains little or no ₂ or FiO (0.5 wt% or less), and has a glittering sensation itself.

The pearl pigment coated with titanium dioxide has a flat plate shape (hexagonal plate shape) and has a longitudinal dimension of 5 to 15 μm.
Preferably 10 to 15μ, the thickness is 1/10 to 1/20 in the longitudinal direction,
It is preferably 1/10 to 1/15. When the longitudinal direction is smaller than 5 μ, the glittering property is deteriorated, while when it is larger than 15 μm, the glittering property is too strong and the top coating film needs to be thick, which is not economically preferable. Further, when the thickness is more than 1/10 with respect to the longitudinal direction, the pearl pigment tends to cue from the coated surface and the finishability is deteriorated, while when it is less than 1/20, the glitter is changed. The size of the pearl pigment in the longitudinal direction is measured by a particle size distribution measuring device using a laser [PARTICLE SIZER2200, manufactured by MALVERN (UK)]. With respect to the longitudinal dimension of the pearlescent pigment, most of it (eg, about 90% by weight or more, preferably 95%
Is more than 30%, and "longitudinal dimension (average central particle size) of 5 to 15" in the present invention means that those within this range are 40% by weight or more in all pearl pigments, preferably The content is preferably 50% by weight or more, and "preferably 10 to 15 µ" means that the content of this range in all pearl pigments is 25% by weight or more, particularly 32% by weight. Therefore, in the present invention, it is necessary that the content of the pearl pigments larger than 15 μ and 30 μ or less is 45% by weight or less, particularly 43% by weight or less based on the total pearl pigments.

The titanium dioxide that coats the surface of the iron oxide particles is generally of the anatase type, but when the rutile type is used, the weather resistance is improved.

Regarding the pearl pigment used in the component (3), the ratio of the titanium dioxide layer coated is 0.1 based on the total weight of the pearl pigment.
-30% by weight, particularly 0.3-30% by weight is preferred. If the proportion of the titanium dioxide layer is less than 0.1% by weight, the problem that interference color cannot be obtained tends to occur, while if it exceeds 30% by weight, the colorful interference color peculiar to the pearl pigment cannot be obtained, and There is a tendency that the coating film becomes more tinged with difficulty.

Such pearl pigment, the iron oxide particles titanyl sulfate _{(TiOSO 4 · 5.2H 2 O)} , titanium tetrachloride (TiCl _4), zirconium sulfate _{(Zr (SO 4) 2 ·} 4H 2 O) a metal oxide such as It can be obtained by heating in a solution of (hydroxide is also possible), washing with water and drying. Furthermore, if this dried product is roasted at about 600 ° C. and crystallized, weather resistance and gloss are improved. When these are heat-treated with aluminum sulfate (Al ₂ (SO ₄ ) ₃ / 18H ₂ O) or the like, the color tone can be changed. The pearl pigment thus obtained can have its color tone arbitrarily adjusted by the treatment agent and the treatment method described above. For example, blue, greenish blue, yellow, purple, reddish purple, reddish brown, yellowish brown, gold, etc. It can be toned, and its surface has excellent brilliance.

The amount of the pearl pigment is 0.1 to 30 parts by weight per 100 parts by weight of the vehicle component (total solid content of the base resin and the curing agent),
Particularly, 5 to 20 parts by weight is preferable. The amount of pearl pigment is 0.
If the amount is less than 1 part by weight, there is a tendency that a defect that a glittering feeling peculiar to a pearl pigment cannot be obtained occurs. On the other hand, if the amount of the pearl pigment blended is more than 30 parts by weight, there is a tendency that the durability deteriorates.

The method of blending (dispersing) the pearl pigment in the vehicle component is not particularly limited, but it is preferable to avoid strong dispersion in order not to destroy the titanium dioxide layer coated.
It can be easily dispersed with a normal disper stirrer.

In the pearl pigment-containing coating containing a pearl pigment and a vehicle component as main components, in addition to the both components, a usual metallic pigment, a coloring pigment, an extender pigment, various additives for coating, etc. may be added according to the present invention. It can be blended to such an extent that the desired excellent designability is not impaired.

Component (4): Powder coating The powder coating is a thermosetting powder coating which is already known per se and is applied to the coating surface of the component (3). A powder coating material that forms a transparent coating film that allows a pearl pigment-containing coating film to be seen through, and contains little or no colorant or metallic pigment, and contains a base resin and a curing agent as main components.

The base resin is the main component for forming a coating film by the component (4), and is an acrylic resin, polyester resin, fluororesin, urethane having one or more crosslinkable functional groups selected from hydroxyl group, carboxyl group, glycidyl group and the like. Examples include, but are not limited to, resins and their modified forms (eg, graft weight). The glass transition temperature of the base resin is preferably 50 ° C. or higher, particularly preferably 60 to 120 ° C. The composition and molecular weight can be arbitrarily selected according to the purpose and are not particularly limited.

The curing agent is for three-dimensionally crosslinking and curing the above-mentioned base resin by heating, and for example, an alkoxymethylolmelamine, a block polyisocyanate compound, an epoxy compound, an isocyanurate compound and an aliphatic dibasic acid can be used.

Most preferably, the ratio of the base resin to the curing agent is such that the molar ratio of the functional groups in the base resin to the functional groups in the curing agent is approximately equimolar.

The component (4) may be blended with a flow regulator, an ultraviolet absorber, a light stabilizer, etc., if necessary.

The component (4) is obtained by melt-kneading the above components and cooling the mixture.
It is obtained by crushing, and these steps, particle size and the like are conventional.

Also. The coating method of the component (4) is not particularly limited,
For example, electrostatic spray coating, fluidized dipping method, etc. may be mentioned.
The coating film thickness can be arbitrarily selected, for example, the range of 40 to 200μ is suitable, and among them, the smoothness of the coating film, sharpness, gloss,
In order to improve the feeling of flesh and the like, it is preferable to apply a coating having a film thickness of 80 to 120 μm.

The present invention is characterized in that the coating materials of the above-mentioned components (1) to (4) are successively applied. Specifically, the cationic electrodeposition coating composition of component (1) is applied, washed with water, heated to about 150 to about 230 ° C. to cure the coating film, and then (2) is applied to the surface of the electrodeposition coating film.
Based on the cured coating film, apply the colored paints of the components to a film thickness of about 10 to 50μ. Then, on the coated surface of the component (2), (3)
When applying the pearl pigment-containing paint of the component, the coating film of the component (2) may be pre-cured by heating (about 120 to about 200 ° C), but at room temperature or low temperature (about 100 ° C). In the following), it may be left as it is to remove a part or most of the water and / or the organic solvent in the coating film. The coating of the component (3) is applied to the coating surface of the component (2) so as to have a film thickness of about 15 to 50 μ (based on the cured coating film), and the explanation is given for the coating film of the component (2). In the same manner, after heating or leaving it to stand, apply the powder coating of the component (4) and heat to about 120-200 ° C to
Only the coating film of the component or further coating films are simultaneously cured.

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. "Parts" and "%" are "parts by weight"
And "% by weight".

I Sample preparation (1) Component: i) (A) Preparation of epoxy-based cationic electrodeposition resin Bisphenol-type epoxy resin (Chiragaigi "Araldite # 6071") 930 parts Bisphenol-type epoxy resin (Ciba Geigy "Araldite" GY2600 ") 380〃 Polycaprolactone diol (" Plaxel # 205 "manufactured by Daicel) 550〃 Dimethylbenzylamine acetate 2.6〃 p-Nonylphenol 79〃 Monoethanolamine methyl isobutyl ketone ketimide 71〃 Diethanolamine 105〃 Butyl cellosolve 180〃 Cellosolve 525〃 component ~ together and after reacting at 150 ℃ for 2 hours,
Ingredients ~ are mixed and reacted at 80 to 90 ° C for 3 hours to obtain a resin solution having a solid content of 75%. The surface strength of this resin is 53 dyne
/ cm.

ii) Preparation of (B) nonionic film-forming resin (B-1)
Production of butyl cellosolve 26 parts 80% polyester monomer ("FM-3X" manufactured by Daicel) 37.5〃 styrene 40〃 hydroxyethyl methacrylate 25〃 n-butyl methacrylate 5〃 AIBN (azobisisobutyronitrile) 4〃 butylcellosolve 5〃 Azobis dimethyl valeronitrile 0.5〃 cellosolve 23〃 component is heated to 130 ℃, and at 130 ℃, the components ~ are added dropwise over 5 hours, then at 130 ℃ is maintained for 2 hours, then at 130 ℃ is added over 2 hours. And maintain at 130 ° C. for 2 hours, then add ingredients and cool.

Thus, a resin solution having a solid content of 62% and a number average molecular weight of about 5,000 and a surface tension of 40 dyne / cm is obtained.

Production of (B-2): Butylcellosolve 26 parts 80% Polyester monomer (FM-3X manufactured by Daicel) 87.5〃 Styrene 25〃 Hydroxyethyl acrylate 5〃 AIBN (Azobisisobutyronitrile) 4〃 Butylcellosolve 5〃 Azobisdimethyl Valeronitrile 0.5 〃 Cellosolve 23 〃 component is heated to 130 ℃, at 130 ℃ component ~ is added dropwise over 5 hours, then maintained at 130 ℃ for 2 hours, and the component is added over 2 hours at 130 ℃, Hold at 130 ° C. for another 2 hours, then add ingredients and cool. Thus at 62% solids. Number average molecular weight of about 5,000 and surface tension of 35 dyne / cm
To obtain a resin solution of.

iii) Manufacture of emulsion Resin solution mixture (resin having composition ratios of components (A) and (B) shown in Table 1 below) 82.6 parts as solid content 4,4'-diphenylmethane diisocyanate ethylene glycol Mono 2-ethylhexyl ether diblock 5.0〃 isophorone diisocyanate methyl ethyl ketone ketoxime diblock 12.4〃 polypropylene glycol 4000 0.5〃 lead acetate 1.0〃 10% acetic acid 9.3〃 deionized water 187.75〃 In addition, the mixture is further uniformly mixed, and then the ingredients are added and uniformly stirred and mixed to obtain an emulsion having a nonvolatile content of 32% (120 ° C to 1 hr.).

iv) Manufacture of pigment paste 60% Quaternary chlorinated epoxy resin (dispersion medium) 5.73 parts Titanium white 14.5〃 carbon 0.54〃 extender pigment (clay) 7.0〃 lead silicate 2.3〃 dibutyltin oxide 2.0〃 deionized water 27.49〃 A non-volatile content of 50% (120 ° C to 1 hr.) Is obtained as a pigment paste.

317.2 parts of an emulsion, 59.56 parts of a pigment paste and 279.64 of deionized water obtained based on the mixing ratio (resin weight solid content ratio) shown in Table 1 for the above (A component) and (B component).
The parts are mixed to obtain a cationic electrodeposition coating bath [component (1)] (solid content 20%).

(2) Component: (i) Acrylic resin water dispersion (W-1) 140 parts of deionized water and 30% Newcol 707SF in a reaction vessel.
Add 2.5 parts and 1 part of the following monomer mixture (1), stir and mix in a nitrogen stream, and add 3 parts of 3% ammonium persulfate at 60 ° C. Then, after raising the temperature to 80 ° C., 79 parts of the following monomer mixture (1), 30% Newcol 707SF 2.5
Parts, 4 parts of 3% ammonium persulfate and 42 parts of deionized water are added to the reaction vessel using a metering pump over 4 hours. After the addition is completed, aging is carried out for 1 hour.

Furthermore, at 80 ° C., 20.5 parts of the following monomer mixture (2) and 3
% Aqueous ammonium persulfate solution (4 parts) are simultaneously dropped into the reaction vessel in parallel over 1.5 hours. Aging for 1 hour after the addition,
Passed with 200mesh nylon cloth at 30 ° C. Add deionized water to this and add dimethylaminoethanol.
Adjusted to pH7.5, average particle size 0.1μ, Tg (glass transition temperature)
A 20% acrylic resin aqueous dispersion W-1 having a nonvolatile content of 46 ° C. was obtained.

Monomer mixture (1) Methyl methacrylate 55 parts Styrene 10 n-Butyl acrylate 9 2-hydroxyethyl acrylate 5 Methacrylic acid 1 Monomer mixture (2) Methyl methacrylate 5 parts N-butyl acrylate 7 Acrylic acid 2-Ethylhexyl 5 Methacrylic acid 3 30% Newcol 707SF 0.5 (Note) 30% Newcol 707SF is a surfactant manufactured by Nippon Emulsifier Co., Ltd. (ii) Acrylic resin aqueous solution (W-2) 60 parts of butyl cellosolve and 15 parts of isobutyl alcohol are placed in a reaction vessel. In addition, warm to 115 ° C in a nitrogen stream, 115
When the temperature reached ℃, a mixture of 26 parts of n-butyl acrylate, 47 parts of methyl methacrylate, 10 parts of styrene, 10 parts of 2-hydroxyethyl methacrylate, 6 parts of acrylic acid and 1 part of azoisobutyronitrile was used for 3 hours. Add. After the addition is complete
Azobisisobutyronitrile 1 aged for 30 powders at 115 ℃
Part and butyl cellosolve 115 parts are added over 1 hour, aged for 30 minutes and passed through a 200 mesh nylon cloth at 50 ° C.

The acid value of the obtained reaction product was 48, the viscosity was Z ₄ (Gardner foam viscometer), the nonvolatile content was 55%, and the Tg was 45 ° C. This product was neutralized with dimethylaminoethanol in an equivalent amount, and deionized water was added to obtain a 50% acrylic resin aqueous solution (W-2).

(Iii) Preparation of (2) component colored coating (aqueous) (2) -1 to (2) -3: A mixture of 40 parts of an acrylic resin aqueous solution (W-2) and 20 parts of butyl cellosolve is shown in Table 2. Add the indicated pigment components and disperse to 5 μm or less with Pebulmine, then add acrylic resin water dispersion (W-1) 275 parts Cymel 350 (Mitsui Toatsu Chemicals, Inc., amino resin) 25 parts deionized water 111 Part was added to adjust the viscosity to 2500 cps. The paint containing the pigment component S-1 is designated as (2) -1, and the paint containing S-2 is similarly blended with (2) -2 and S-3 (29-3).
And

The light transmittance is measured as described above.

 Film thickness 30μ.

(2) -4: 50% acrylic resin liquid (Note 1) 110 parts 88% Cymel 370 (Note 2) 28 parts Pigment component (S-1 in Table 2) 67 parts Dibutyl acid phosphate 0.3 parts A mixed solvent consisting of 30 parts of toluene, 20 parts of isobutyl alcohol, 30 parts of cellosolve acetate and 20 parts of butyl cellosolve has a viscosity of 13 seconds (Ford Cup N
o.4 / 20 ℃).

(Note 1) 50% acrylic resin liquid: 30 parts of methyl methacrylate, 59 of ethyl acrylate
Part, hydroxyethyl acrylate 10 parts and acrylic acid 1 part are polymerized in a mixed solvent of xylene / n-butanol = 70/30 using a polymerization initiator α, α′-azobisisobutyronitrile as a weight average. Acrylic resin liquid with a molecular weight of 25,000 and resin solid content of 50%.

(Note 2) 88% Cymetal 370: Contains 55% based on solid content of mononuclear body of methoxylated methylolmelamine, which is a trade name of Mitsui Cyanamide Co., Ltd. and which has both a methoxy group and a methylol group.

(2) -5: 50% acrylic resin liquid (Note 1) 100 parts 88% Cymel 370 (Note 2) 12 parts Pigment component ((S-2) in Table 2) 38 parts Dibutyl acid phosphate 0.1 part The above mixture Was adjusted in the same manner as in (2) -4 above.

(2) -6: 50% acrylic resin liquid (Note 1) 110 parts 100% Cymel 303 (Note 3) 25 parts Pigment component ((S-3) in Table 2) 40 parts Catalyst 6000 (Note 4) 0.2 Parts The above mixture was prepared in the same manner as in the above (2) -4.

(Note 3) 100% Cymel 303: trade name manufactured by Mitsui Cyanamid Co., Ltd., containing 85% based on solid content of hexamethoxymethylolmelamine, which is a triazine mononuclear body obtained by methoxylation of all 6 methylol groups.

(Note 4) Catalyst 6000: Trade name, sulfonic acid catalyst, manufactured by Mitsui Toatsu Chemicals, Inc.

The color tone and light transmittance of the formed coating films of (2) -4 to (2) -6 correspond to those of (2) -1 to (2) -3.

Component (3): (3) -1 to (3) -2: Acrylic resin aqueous dispersion (W-1) 275 parts Acrylic resin aqueous solution (W-2) 40 Cymel 350 25 Pearl pigment (Table 3) Butyl cellosolve 20 Deionized water 253 was mixed, and Chikusol K-130B (a thickener manufactured by Kyoeisha Oil and Fat Chemical Co., Ltd.) was added, and a B type viscometer (rotor speed 6r
pm) to 3000 cps to obtain a pearl pigment-containing coating (aqueous) as component (3). The mixture of pearl pigment M-1 is (3) -1, and M-2 is (3) -2.

(3) -3: The pigment component of (2) -4 above was added to (M-1) 10 in Table 3 below.
Manufactured in the same manner as (2) -4 except that the parts were replaced.

(3) -4: The pigment component of the above (2) -5 is added to (M-2) 13 of Table 3.
Produced in the same manner as (2) -5 except that the parts were changed.

(4) Component: (4) -1: 40 parts of methyl methacrylate and acrylic acid-2 in a flask.
-Ethylhexyl 30 parts, glycidyl methacrylate 30 parts,
10 parts of styrene, 1 part of t-butyl peroxide (polymerization initiator), and 2 parts of potassium oleate soap (surfactant) were charged, and heat polymerization was carried out by a suspension polymerization method to obtain a particulate copolymer (glass transition). The temperature was about 60 ° C). 100 parts of the obtained copolymer, 25 parts of decamethylene dicarboxylic acid,
1 part of the coating surface conditioner was melt-kneaded for 10 minutes at 120 ° C. using a heating kneader. Then, the kneaded product was cooled and then pulverized by using a pulverizer to obtain a clear powder coating having a particle size of about 20 to 150 μm.

Examples and Comparative Examples Table 4 shows Examples and Comparative Examples.

The coating process is as shown in Table 4. First, the zinc phosphate-treated iron plate product coated object (cathode) was immersed in a cationic electrodeposition coating bath [(1) component] to form an anode as a counter electrode. In the atmosphere with a nitrogen dioxide concentration of about 10 ppm, after applying water for 3 minutes at a voltage that gives a cured coating thickness of 20μ,
The electrodeposition coating film was cured by heating at 70 ° C. for 20 minutes.

Next, using a spray gun (Devilbiss JGA502) as a first overcoat on the electrodeposition coated surface, a colored paint [(2) component] was applied at a temperature of 25 ° C. and a humidity of 70% to obtain a cured film thickness of 20 to 30.
The coating is applied so that it has a thickness of μ, and then it is heated and dried at 80 ° C. for 5 minutes in order to remove a part or most of the volatile components in the coating film. (3) component) is similarly coated so that the cured film thickness becomes 13 to 20 μm, and is similarly dried at 80 ° C. for 5 minutes, and then the powder clear coating [(4 Component)] by an electrostatic powder coating method to a cured coating film thickness of 80-100μ, and then heating at 150 ° C for 30 minutes, [2],
The coating films of the components [3] and [4] were simultaneously cured.

In Table 1, (* 1) The mixing ratio of the (A) component and the (B) component is% by weight.
Is.

(* 2) Based on the cured coating film.

(* 3) Of component (1) above, only component (A)
A cationic electrodeposition paint produced without blending the component (B).

(* 4) Amino-alkyd resin-based intermediate coating.

(* 5) A paint in which the pearl pigment in the paint of (3) -3 is replaced with an aluminum flake pigment.

(* 6) Diluted with an organic solvent thinner using an organic solvent type thermosetting acrylic resin-based clear paint and applied by air spray method.

(* 7) The gloss retention rate of the electrodeposition coating is as follows. The electrodeposition coating is applied as above, and the heat-cured coated plate is accelerated and exposed for 40 hours with a sunshine weatherometer (light intensity is 1100 Kjuole / m ² · hr). The rate of change (%) in gloss (60 ° specular reflectance) with that before the pomegranate was examined. A digital gloss meter GM-26D type (sold by Murakami Color Research Laboratory) was used for initial and 40-hour irradiation gloss measurement. The gloss retention is calculated by the following formula.

(* 8) Similar to (* 7), the coated plate that had been top-coated was accelerated for 4000 hours, then immersed in 40 ° C warm water for 20 hours, and then cross-cut to reach the substrate. Perform tape peeling. If there is no peeling on the electrodeposition coated surface, it is ○, and if there is, it is ×.

(* 9) Image clarity measuring instrument JCRI-PGD-166 type cd meter (sold by: Japan Color Research Institute) was used.

(* 10) Visual evaluation.

○ Good × Poor (* 11) Economical efficiency is indicated by the number of times that heat curing is required after coating the paint. The smaller the number of times, the lower the production cost and the better the economic efficiency.

(* 12) Visual evaluation ◯: Excellent feeling of flesh, luster, and color design.

X: These performances are insufficient.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yuzo Miyamoto 4-17-1, Higashi-Hachiman, Hiratsuka-shi, Kanagawa Kansai Paint Co., Ltd. (72) Inventor Eisaku Nakatani 4-17-1, Higashi-Hachiman, Hiratsuka, Kanagawa Paint Co., Ltd. (72) Inventor Tadayoshi Tatsuno 4-17-1, Higashi-Hachiman, Hiratsuka-shi, Kanagawa Kansai Paint Co., Ltd. (72) Inventor, Masafumi 4-1-1, Higashi-Hachiman, Hiratsuka-shi, Kanagawa Kansai Paint Co., Ltd. Hiroshi Shijosho

Claims (1)

(57) [Claims] (1) Electrodeposition paint, (2) Colored paint, (3)
A method in which a pearl pigment-containing coating and (4) a clear coating are sequentially applied to finish, wherein (1) the electrodeposition coating has (A) a surface tension of 40 to 60 dyne / cm and is neutralized with an acid. By using an epoxy-based cationic electrodeposition resin capable of forming an aqueous bath capable of electrodeposition on the cathode, and (B) a nonionic film-forming resin having a surface tension of 25 to 45 dyne / cm. (B) = Cathodic electrodeposition for forming a multilayer film, which is contained in a weight ratio within the range of 60:40 to 98: 2 and in which the surface tension of the resin (A) is larger than the surface tension of the resin (B). The above-mentioned (2) colored paint is a liquid colored paint having an average light transmittance of 5% or less at a wavelength of 400 to 700 nm in a coating film having a thickness of 30 μ after curing, and (3) Pearl as described above. Pigment-containing paint as pearl pigment,
Iron oxide particles containing at least 80% by weight of α-iron oxide crystals are coated with titanium dioxide, and the dimension in the longitudinal direction (average central particle diameter) is 5 to 30 μ, and the thickness is 1/10 to 1/1 of the longitudinal direction. 20
And the pearl pigment is 0.1 to 30 parts by weight per 100 parts by weight of vehicle component (solid content), which is a liquid coating, and the (4) clear coating is a powder coating containing no colorant. A paint finishing method characterized by the above.