JPH08283625A - Metallic coating material and coating method using the same - Google Patents

Abstract

PURPOSE: To obtain a metallic coating material containing an organic solvent- type aluminum pigment treated with a specific compound, causing no cohesive failure of the coating film therefrom, excellent in coating film adhesiveness, developing no discoloration thereof, and high in storage stability. CONSTITUTION: This coating material contains an organic solvent-type aluminum pigment which is obtained by treating (A) aluminum frame pref. 5-40μm in average size D50 with >=0.01wt.%, on P basis, of (B) a phosphoric ester prepared by esterification between a polyfunctional epoxy compound and a phosphorus compound or (C) a phosphoric ester salt prepared by neutralizing the component B with an amine or amide compound. The compound B is e.g. a compound of formula II prepared from an alicyclic epoxy compound and a compound of formula OP(OH)3 . In general, this coating material essentially contains a vehicle component and an organic solvent which are pref. a thermosetting resin composition containing e.g. an acrylic resin and a hydrophobic solvent, respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metallic paint having excellent cohesive failure resistance in a coating film and free from discoloration (bleaching) of the paint, and a coating method using the metallic paint.

[0002]

2. Description of the Related Art Organic solvent-based metallic paints containing aluminum pigments have already been widely used for coating automobile exterior panels. A two-coat method is also known in which the organic solvent type metallic paint and the clear paint that forms a transparent coating film are sequentially applied.

The aluminum pigment in the metallic paint is usually produced by wet-milling aluminum in the presence of a lubricant such as saturated or unsaturated fatty acid such as stearic acid or oleic acid. The surface of the aluminum pigment thus treated is deactivated,
When anthraquinone-based, pyranthrone-based, quinacridone-based, and perylene-based organic pigments coexist in the system, these organic pigments may be discolored (decolorized) in the paint.

In order to prevent such discoloration, it has been considered to treat the aluminum pigment after pulverization with an aliphatic amine, but there was little effect. In addition, after the treatment with the above fatty acid, further treatment with water dispersed in isopropyl alcohol (see Japanese Examined Patent Publication No. 63-25634) or treatment with an acidic phosphoric acid ester compound (Japanese Patent Publication No. 2-31751)
However, it was difficult to solve the discoloration prevention.

Further, in the organic solvent type metallic paint, it is necessary to mix 8 PHR or more of aluminum pigment (8 parts by weight of aluminum pigment per 100 parts by weight of the resin solid content in the paint) in order to finish it in silver or light color. When the aluminum pigment treated by the above method is blended to this extent, the adhesion to the vehicle component in the coating film is not sufficient, and as a result, there is a defect that cohesive failure occurs in the metallic coating film.

[0006]

The object of the present invention is to solve the above problems (discoloration of organic pigment and cohesive failure in metallic coating film).
The present invention relates to an organic solvent-type metallic pigment and a two-coat method using the same, which is characterized in that the surface of the aluminum flake is a polyfunctional epoxy compound of 0.01% by weight or more in terms of P element based on the aluminum flake. A phosphoric acid ester (A) produced by an esterification reaction with a phosphorus compound, or an aluminum pigment obtained by treating the phosphoric acid ester (A) with a phosphoric acid ester amine salt (B) obtained by neutralizing the phosphoric acid ester (A) with an amine compound or an amide compound. The present invention has been completed by finding that it is used as a metallic pigment and that it can solve all the above problems.

That is, the present invention is the first invention: a phosphoric acid ester (A) produced by an esterification reaction of a polyfunctional epoxy compound and a phosphorus compound in an amount of 0.01% by weight or more in terms of P element based on aluminum flakes, Alternatively, it is treated with a phosphate ester amine salt (B) obtained by neutralizing the phosphate ester (A) with an amine compound or an amide compound [hereinafter, the components (A) and (B) are generically referred to as "treatment agent"]. Organic solvent type metallic paint containing the organic solvent type aluminum pigment.

Second invention: In a two-coat method of applying a metallic paint and a clear paint, the metallic paint is used as the P element conversion amount for aluminum flakes.
0.01% by weight or more of a phosphoric acid ester (A) produced by an esterification reaction of a polyfunctional epoxy compound and a phosphorus compound, or a phosphoric acid ester amine obtained by neutralizing the phosphoric acid ester (A) with an amine compound or an amide compound A coating method comprising using an organic solvent-type metallic paint containing an organic solvent-type aluminum pigment treated with a salt (B).

The organic solvent-type metallic paint of the first invention of the present invention does not discolor (decolorize) its color tone during storage even when a colored organic pigment is present together, and further, it causes cohesive failure in the coating film. Nor.

The present invention will be described in detail below.

The first aspect of the present invention relates to an organic solvent type metallic paint containing an aluminum pigment surface-treated with a treating agent (hereinafter referred to as "present paint").

In the present coating composition, it is important to use, as the aluminum pigment, one obtained by treating (adsorbing) the surface of aluminum flakes with a treating agent.

The polyfunctional epoxy compound used for preparing the treating agent is a compound having two or more epoxy groups in one molecule, and more specifically, it is an alicyclic hydrocarbon (having 4 to 4 carbon atoms). (Preferably 7), an alicyclic epoxy compound having two or more alicyclic epoxy groups in which an epoxy group is directly bonded to a carbon atom forming a ring, and two or more hydroxyl groups contained in an aliphatic polyhydric alcohol. Examples thereof include aliphatic epoxy compounds formed by glycidyl etherification.

Examples of the alicyclic epoxy compound include 2
It is preferable that one or more alicyclic epoxy groups are bound by a lactone chain or the like. Specific examples include trade names of "Celoxide 2081" and "Celoxide 2085" manufactured by Daicel Chemical Industries, Ltd., and their chemical structural formulas are as follows.

Structural formula of "Celoxide 2081":

[0016]

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Structural formula of "Celoxide 2085":

[0018]

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The alicyclic epoxy compound has a molecular weight of about 300.
To about 1000, especially about 700 to about 1000, the epoxy equivalent is about 150
The preferred range is from about 500 to about 500, especially about 350 to about 500.

The aliphatic epoxy compound is formed by glycidyl etherification of two or more hydroxyl groups contained in the aliphatic polyhydric alcohol. The aliphatic polyhydric alcohol is a compound having two or more hydroxyl groups in one molecule, and specific examples thereof include neopentyl glycol, hexanediol and propylene glycol. An aliphatic epoxy compound can be obtained by converting all the hydroxyl groups of these aliphatic polyhydric alcohols into glycidyl ethers by a known method. The molecular weight of the aliphatic epoxy compound is about
150 to about 1000, especially about 180 to about 400, the epoxy equivalent is about
A range of 100 to about 600, especially about 120 to about 250 is preferred.

The phosphorus compound used in the preparation of the treating agent has the formula
The compound represented by OP (OH) ₃ is preferred.

The treating agent used in the present invention can be obtained by subjecting a polyfunctional epoxy compound and a phosphorus compound to an esterification reaction. This reaction is carried out by the ring-opening reaction of the epoxy group of the polyfunctional epoxy compound and the hydroxyl group of the phosphorus compound, and the reaction conditions can be carried out according to the usual ring-opening reaction. The reaction ratio between the epoxy group of the polyfunctional epoxy compound and the hydroxyl group of the phosphorus compound is most preferably 1: 1.

The following are specific examples of the phosphoric acid ester (A) (treatment agent) thus obtained.

Example using "Celoxide 2081" (Structural Formula 1):

[0025]

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Example using "Celoxide 2085" (Structural Formula 2):

[0027]

[Chemical 4]

Example using an aliphatic diol:

[0029]

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In the formula, n ₁ is an integer of 0 to 9 and X is -C.
H ₂ —CHR ₁ R ₂ —CH ₂ —O— (wherein R ₁ , R ₂
Is hydrogen or -CH ₃ or -CH ₂ -CH ₃ or CH ₂ O
Represented) or by any of H - (CH _{2) n2} -O
- (where n2 is a is an integer from 1 to 6) is represented by, Y ²
Is represented by formula (i) or formula (ii).

[0031]

[Chemical 6]

The treating agent used in the present invention also includes a phosphoric acid ester amine salt (B) obtained by neutralizing the phosphoric acid ester (A) with an amine compound or an amide compound. As the amine compound used for neutralization, for example,
Ammonia: benzylamine, monoethanolamine,
Neopentanolamine, 2-aminopropanol, 3
Primary amines such as aminopropanol and linear or branched aliphatic amines having 1-18 carbon atoms: diethanolamine, dipropanolamine and 1-18 carbon atoms
Secondary amines such as linear or branched aliphatic amines: tertiary amines such as dimethylethanolamine, trimethylamine, triethylamine, triisopropylamine, methyldiethanolamine, dimethylaminoethanol
Primary monoamines: polyethylenes such as diethylenetriamine, hydroxyethylaminoethylamine, ethylaminoethylamine, methylaminopropylamine and the like. Examples of the amide compound used for neutralization is preferably a compound having an amide amino group represented by -CH-C (O) -NH ₂ at its molecular end, for example, lauramide, having 6 to 18 carbon atoms such as stearyl amide Aliphatic amide compounds can be mentioned.

The aluminum flakes used for the preparation of the aluminum pigment to be blended in the metallic paint of the present invention are obtained by crushing and grinding aluminum in a ball mill or attritor mill in the presence of a grinding medium with a grinding aid. It is an aluminum flake manufactured by. From the viewpoint of color tone, the average particle diameter (D ₅₀ ) is about 1 to ₅₀ μm, and particularly 5
It is preferably about 40 μm. As the grinding aid, higher fatty acids such as oleic acid, stearic acid, isostearic acid, lauric acid, palmitic acid and myristic acid, as well as aliphatic amines, aliphatic amides and aliphatic alcohols are used. Aliphatic hydrocarbon solvents such as mineral spirit can be used as the grinding medium. Also,
It is effective to replace the aluminum flakes with an organic solvent capable of dissolving the treatment agent in advance. As such an organic solvent, for example, an aromatic hydrocarbon solvent such as toluene, xylene, solvent naphtha, Solvesso 100 (manufactured by Esso Oil Co., Ltd.) is preferable.

Although the treating agent of the present invention can be used as it is,
For example, it may be diluted in advance with an aromatic hydrocarbon solvent such as toluene, xylene, solvent naphtha, Solvesso 100 (manufactured by Esso Oil Co., Ltd.) or a glycol ether solvent.

The method of treating the surface of the aluminum flakes with the treating agent is carried out by mixing the treating agent and the aluminum flakes with a mixer such as a ribbon type mixer or a kneader type kneader. The amount of the treating agent is 0.01% by weight or more, preferably 0.1 to 5% by weight, more preferably 0.1 to 5% by weight in terms of P element based on the aluminum flake.
~ 1.5% by weight. If it is less than 0.01% by weight in terms of P element, it is difficult to improve discoloration resistance and cohesive failure resistance in the coating film.

The surface of the aluminum flakes is treated with P as a treating agent.
The adsorption of the —OH group prevents the organic pigment from being discolored by being coated with the treatment agent and resulting from the active aluminum surface. Furthermore, the strong cohesive force of the polyfunctional epoxy compound as the treating agent improves the adhesion between the aluminum pigment and the vehicle component in the paint. In particular, even if the content of the aluminum pigment increases, cohesive failure does not occur in the coating film.

The organic solvent type metallic paint of the first invention is
A paint containing an aluminum pigment treated with a treating agent, specifically, the aluminum pigment, a vehicle component and an organic solvent as essential components, and further, if necessary, an organic coloring pigment, an inorganic coloring pigment, an extender pigment. Further, metallic pigments other than the aluminum pigment can be blended.

The vehicle component is preferably a thermosetting resin composition, which comprises a base resin and a crosslinking agent. As the base resin, those known per se can be used, and one or two or more kinds of crosslinkable functional groups selected from a hydroxyl group, an amino group, a blocked isocyanate group, a carboxyl group, an epoxy group, etc. can be used in one molecule. The acrylic resin, polyester resin, urethane resin and the like having the above are particularly suitable.
Examples of the cross-linking agent include melamine resins, block polyisocyanate compounds, and carboxyl group-containing compounds that can be cross-linked and cured with the above-mentioned cross-linkable functional groups.

Any organic solvent may be used as long as it can mix and disperse the above-mentioned vehicle component and aluminum pigment, and aliphatic hydrocarbons, aromatic hydrocarbons, alcohols,
Examples of the solvent include ester type solvents and ketone type solvents. Among them, hydrophobic organic solvents are preferable.

The ratio of the aluminum pigment to the vehicle component is not particularly limited, but the aluminum pigment is 1 to 30 PHR,
Particularly, 5 to 20 PHR is preferable.

Second invention: In a two-coat system for applying a metallic paint and a clear paint, an organic solvent type metallic paint containing an aluminum pigment surface-treated with the above-mentioned treating agent is used as the metallic paint. How to paint.

The metallic paint used in the second invention is selected from the metallic paints (present paint) included in the first invention.

The clear paint is a paint that forms a transparent coating film to be applied on the surface of the metallic paint. Specifically, it contains a vehicle component and an organic solvent as essential components, and if necessary, it is transparent. A color pigment, an extender pigment, a metallic pigment, etc. are blended to such an extent that the feeling is not impaired.

The vehicle component in the clear paint is preferably a thermosetting resin composition, which comprises a base resin and a crosslinking agent. As the basic resin, those known per se can be used, and hydroxyl group, amino group, blocked isocyanate group,
Acrylic resins, polyester resins, urethane resins and the like having one or two or more kinds of crosslinkable functional groups selected from a carboxyl group, an epoxy group and the like in one molecule are particularly preferable. Examples of the cross-linking agent include melamine resins, blocked polyisocyanate compounds, and carboxyl group-containing compounds that can be cross-linked and cured with the above-mentioned cross-linkable functional groups.

Any organic solvent may be used as long as it can mix and disperse the above-mentioned vehicle component and aluminum pigment, and aliphatic hydrocarbons, aromatic hydrocarbons, alcohols,
Examples of the solvent include ester type solvents and ketone type solvents. Among them, hydrophobic organic solvents are preferable.

The coating method according to the second aspect of the present invention is such that the metallic coating material (main coating material) is applied to an object to be coated, which is obtained by applying an undercoat coating material (such as an electrodeposition coating material) and an intermediate coating material to a metal or the like as necessary and curing. To paint. The coating is preferably spray coating such as spraying or electrostatic coating, and the film thickness is preferably 5 to 50 μm, particularly 10 to 30 μm based on the cured coating film, and the coating film is heated at 120 to 160 ° C. to be crosslinked and cured. The clear paint may be applied after that, but the clear paint can be applied to the uncured metallic coating surface without being cross-linked and cured.
Clear coating is also preferably spray coating such as spraying or electrostatic coating, and its film thickness is 10 to 80 μm based on the cured coating.
In particular, 20-60 μm is preferable. Then, it is heated to 120 to 160 ° C. to crosslink and cure only the clear coating film or both the coating film and the metallic coating film.

[0047]

【The invention's effect】

1. Since untreated aluminum pigment is coated with fatty acid etc., if it is mixed in a large amount in the paint, cohesive failure will occur in the coating film and the adhesion of the coating film will decrease, but with this paint, it is treated with a specific treatment agent. Since this aluminum pigment is used, cohesive failure does not occur even if it is blended in an amount of 8 PHR or more, and the coating film adhesion is excellent.

2. When untreated aluminum pigment is mixed with anthraquinone-based, pyranthrone-based, quinacridone-based, and perylene-based organic pigments, discoloration of the organic pigment occurs during storage. Since a pigment is used, such discoloration does not occur at all and storage stability is excellent.

[0049]

EXAMPLES Examples of the present invention and comparative examples will be described below. Parts and percentages are in principle based on weight.

1. Sample preparation 1) Aluminum pigment surface treatment agent 1 kg of aluminum pigment (manufactured by Toyo Aluminum Co., Ltd.,
1 liter of Solvesso 100 (Esso Oil Co., Ltd.) on the pan filter with the product name "Alpaste 7670NS")
A substituted aluminum paste obtained by solvent substitution was used (substituted aluminum paste).

(1) An addition product (Structural Formula 1) (treatment agent) of Celoxide 2081 (manufactured by Daicel Chemical Industries, Ltd.) and a phosphorus compound (OP (OH) ₃ ) was added to aluminum metal 100 of the above-mentioned substituted aluminum paste. Content of P element to parts
0.25% was added, and the aluminum pigment was surface-treated by mixing with a kneader mixer for 30 minutes [treated aluminum pigment (1)].

(2) An addition product (Structural Formula 2) (treatment agent) of Celoxide 2085 (manufactured by Daicel Chemical Industries, Ltd.) and a phosphorus compound (OP (OH) ₃ ) is added to the aluminum metal 100 of the above substituted aluminum paste. Content of P element to parts
0.25% was added, and the aluminum pigment was surface-treated by mixing with a kneader mixer for 30 minutes [treated aluminum pigment (2)].

[0053] (3) The second Celloxide 2085 and phosphorus compound to neutralize a portion of the adduct 1 mole phosphoric acid group by reacting the di-laurylamine 1 mole of the (OP (OH) _3), the so Replacement Aluminum Paste Aluminum Metal 100
Compounded so that the P element content rate is 0.25%,
The aluminum pigment was surface-treated by mixing with a kneader mixer for 30 minutes [treated aluminum pigment (3)].

(4) Neopentyl glycol diglycidyl ether (manufactured by Daicel Chemical Industries, Ltd.) and a phosphorus compound (O
P (OH) ₃ ) and its adduct (treatment agent) are added to P of 100 parts of aluminum metal of the above-mentioned substituted aluminum paste.
The treated aluminum pigment (4) was prepared by blending so that the element content would be 0.25%, and mixing with a kneader mixer for 30 minutes to surface-treat the aluminum pigment.

2) Preparation of Resin for Metallic Paint 30 parts of styrene, 40 parts of n-butyl methacrylate in an organic solvent consisting of 85 parts of xylol and 15 parts of n-butanol.
Parts, 2-ethylhexyl acrylate 10 parts, 2-hydroxyethyl acrylate 18 parts, and acrylic acid 2 parts are copolymerized, and the number average molecular weight is about 6600, the resin solid content is 50%, and the Cardner viscometer (25 ° C). A hydroxyl group-containing acrylic resin solution of J was obtained.

3) Preparation of clear paint 25 parts of methyl acrylate, 25 parts of ethyl acrylate, n
-A monomer component consisting of 36.5 parts of butyl acrylate, 12 parts of 2-hydroxyethyl acrylate and 1.5 parts of acrylic acid was polymerized in xylene in the presence of 2.5 parts of a polymerization initiator (α, α'-azobisisobutyronitrile). An acrylic resin solution having a solid content of 60% was obtained. This resin had a hydroxyl value of 58 and an acid value of 12.

This resin solution and "Uban 20SE" (manufactured by Mitsui Toatsu Chemicals Inc., butyl etherified melamine resin) were mixed at a solid content ratio of 75:25, and "Swasol # 15" was added.
00 ”(made by Cosmo Oil) with a viscosity of 25 seconds (Ford Cup # 4
/ 25 ° C) to obtain a clear paint.

2. Examples and Comparative Examples of Metallic Paints The surface-treated aluminum pigments and resins for metallic paints (hydroxyl group-containing acrylic resin) described above are mixed in the compositions and ratios shown in Table 1 to obtain the organic solvent-based metallic paints of the present invention. It was The numerical values in Table 1 are the solid content, and the viscosity was 15 seconds (Ford cup # 4/25 ° C) with "Solvet # 100" (manufactured by Esso Oil Co., Ltd.) to obtain a metallic paint. The discoloration resistance of the coating film was examined using this metallic paint. The results are also shown in the table.

[0059]

[Table 1]

(* 1) U-Van 28-60: Mitsui Toatsu Chemical Co., Ltd., trade name, butyl etherified melamine resin (* 2) Untreated aluminum pigment: Toyo Aluminum Co., Ltd., "Alpaste 7670NS" 3 ． Examples and Comparative Examples of Metallic Pigments The above-mentioned surface-treated aluminum pigments and resins for metallic paints (hydroxyl group-containing acrylic resin) are mixed in the compositions and ratios shown in Table 2 to obtain the organic solvent-based metallic paints of the present invention. It was The numerical value in Table 2 is the solid content, and the viscosity was 15 seconds (Ford cup # 4/25 ° C) using "Solvesso # 100" (manufactured by Esso Oil Co., Ltd.) to obtain a metallic paint. Using this metallic paint, the cohesive failure resistance of the coating film was examined. The results are also shown in the table.

[0061]

[Table 2]

4. Examples of coating method and comparative examples A chemical conversion treated dull steel plate is coated with an epoxy resin-based cationic electrodeposition coating (cured film thickness: 25 μm) and heated at 170 ° C. for 30 minutes to cure, and then Rugabak AM as an intermediate coating.
(Kansai Paint Co., Ltd., polyester resin / melamine resin system) was applied (cured film thickness: 30 μm) and heated at 140 ° C. for 30 minutes to cure. Then, the coated surface of the intermediate coating was water-polished with # 400 sandpaper, drained and dried, and the coated surface was wiped with petroleum benzine as a material. The metallic paints obtained in the above Examples and Comparative Examples were applied to this material by air spray coating (cured film thickness 15 to 20 μm), allowed to stand at room temperature for 3 minutes, and then the above clear coating was similarly applied (cured film). Thickness 35-40 μm). Then leave it at room temperature for 10 minutes, then
Both coatings were simultaneously cured by heating at 0 ° C for 30 minutes. The thus-obtained 2-coat coating film was examined for discoloration resistance and cohesive failure resistance.

The discoloration resistance is determined by the metallic paint (Examples 1 to 1).
4 and Comparative Example 1) were stored at 50 ° C. for 2 weeks, and the stored product and the product immediately after production were coated as described above, and the color difference before and after storage was determined. The color difference was measured using an SM color computer (manufactured by Suga Test Instruments Co., Ltd.).

The cohesive failure resistance was measured by cutting the obtained two-coat coating film with a knife so as to reach the substrate and measuring 1 mm × 1 mm in size.
The number of coatings of the remaining burdock after the adhesive cellophane tape was attached to the surface of the burdock was made, and the film was rapidly peeled off.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ichiro Takagi 3-6-8, Kutaro-cho, Chuo-ku, Osaka-shi, Osaka Toyo Aluminum Co., Ltd.

Claims (2)

[Claims] 1. A phosphate ester (A) produced by an esterification reaction of a polyfunctional epoxy compound and a phosphorus compound in an amount of 0.01% by weight or more in terms of P element based on aluminum flakes, or the phosphate ester (A). An organic solvent-type metallic coating material containing an organic solvent-type aluminum pigment treated with a phosphoric acid ester amine salt (B) obtained by neutralizing the above with an amine compound or an amide compound. 2. A two-coat method of applying a metallic paint and a clear paint, wherein the metallic paint is:
Phosphate ester (A) produced by the esterification reaction of a polyfunctional epoxy compound and a phosphorus compound in an amount of 0.01% by weight or more in terms of P element relative to aluminum flakes, or an amine compound or an amide of the phosphate ester (A) A coating method comprising using an organic solvent type metallic paint containing an organic solvent type aluminum pigment treated with a phosphoric acid ester amine salt (B) neutralized with a compound.