JPH11323181A - Metallic pigment, production of metallic pigment, assistant for production of metallic pigment, water-based coating material containing metallic pigment, and water-base ink containing metallic pigment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a metallic pigment improved in storage stability, adhesion to substrates, and appearance by incorporating a powdery metal coated with an organosulfur compound. SOLUTION: 100 pts.wt. one or more powdery metals selected among aluminum, copper, and zinc and having a mean length of 100 μm or below, desirably, 1-50 μm, an average thickness of 5 μm or below, desirably, 2 μm or below and an average aspect ratio of 3 or above, desirably, 10 or above and 0.1-20 pts.wt., desirably, 0.5-10 pts.wt. organosulfur compound containing a higher aliphatic hydrocarbon group are ground and mixed to obtain the powdery metal coated with the organosulfur compound. The coated metal is mixed with 0-50 wt.%, desirably, 0-20 wt.% ink resin such as a maleate resin, an acrylic resin, shellac, a rosin-modified phenolic resin, a petroleum resin, or an alkyd resin and 0-50 wt.%, desirably, 0-30 wt.% aqueous solvent for an ink.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal pigment, a method for producing a metal pigment, an auxiliary for producing a metal pigment, a water-based paint containing a metal pigment, and a water-based ink containing a metal pigment. A metal pigment capable of realizing excellent adhesion to an adherend and excellent appearance when adhered to an adherend, a method for producing a metal pigment, an auxiliary for producing a metal pigment, an aqueous paint containing a metal pigment, And a metal pigment-containing aqueous ink.

[0002]

2. Description of the Related Art Conventionally, it is possible to prevent corrosion of building materials and the like in metallic paints, buildings, bridges, etc., which can be suitably used for exteriors of automobiles, home electric appliances and the like. Heavy duty anti-corrosion paint,
In a paint such as a rust preventive paint that can prevent rust on the metal surface, and in an ink such as a printing ink, a pigment component can be blended.

[0003] As the pigment component, for example, metal pigments represented by aluminum dust, zinc dust and the like can be suitably employed. For example, when this metal pigment is mixed with the rust preventive paint or the like, when the rust preventive paint adheres to the adherend, the rust preventive property (also referred to as “corrosion resistance”) of the adherend is improved. Can also be
Metallic luster derived from aluminum dust, zinc dust and the like can be imparted to the surface of the adherend.

Further, for example, when the metal pigment is mixed with the printing ink or the like, when the printing ink adheres to the object, the color characteristics of an image formed on the object, such as color tone, can be easily improved. And a metallic luster can be imparted to the image formed on the adherend.

On the other hand, in recent years, for the purpose of saving resources, eliminating pollution, and improving the safety between users and manufacturers, the above-mentioned paints and inks include, for example, organic solvent reduction containing an extremely small amount of organic solvent. Paint and organic solvent reduced ink,
Non-organic solvent-based paints and non-organic solvent-based inks containing no organic solvent are desired, and in particular, water-based paints and water-based inks using water-based solvents are strongly desired.

However, in the above-mentioned aqueous paints and aqueous inks, for example, when the metal pigment is present in an aqueous solvent, if the dispersion stability of the metal pigment is poor, the metal pigment naturally precipitates. Etc., and furthermore, regardless of the dispersion stability of the metal pigment, the problem of poor storage stability of aqueous paints and aqueous inks, specifically, for example, the metal pigment reacts with water to form a metal pigment. Corrosion of metal pigments, deterioration of water-based paints and water-based inks due to corrosion of metal pigments, deterioration of water-based paints and water-based inks more quickly than without metal pigments, etc. was there.

As a method for producing the metal pigment, for example,
Japanese Patent Application Laid-Open No. 63-103007 discloses a method employing "metal powder obtained by making molten metal fine by rounding off the center". In this method, for example, finer powder is made by rounding off the center. The particle shape of the metal powder
In addition, due to being close to a spherical shape, good dispersion stability of the metal powder could not be secured, and storage stability of the metal powder was insufficient.

Further, for example, a powdered metal and a grinding aid are used as a grinding aid with a saturated fatty acid such as stearic acid, an unsaturated fatty acid such as oleic acid, and derivatives thereof.
For example, pulverization by kneading with a ball-type kneading machine such as an attritor, a ball mill, a stamp mill, and a vibration mill,
There is a method of spreading and producing a metal pigment.In the metal pigment obtained by this method, for example, the dispersion stability of the metal pigment is good only in the initial stage, but particularly in an aqueous solvent. Poor storage stability, for example, the corrosion stability of the metal pigment deteriorates over time due to corrosion of the metal pigment, and furthermore, a large amount of gas is generated by the reaction between the metal pigment and water, so that paints and inks There is a problem that the properties in such as are significantly impaired.

Therefore, for the purpose of improving the storage stability of the water-based paints and water-based inks, for example, Japanese Patent Application Laid-Open No. 4-306265 discloses a "metal pigment coated with an isocyanate compound and phosphoric acid". Japanese Patent Application Laid-Open No. Hei 7-133440 discloses a "metal pigment coated with an epoxy compound and molybdic acid".
However, in these methods, for example, a special post-treatment is required after pulverizing a powdered metal, which makes the manufacturing process complicated and disadvantageous in terms of cost. Including the acid components such as phosphoric acid and molybdic acid causes various restrictions in the process of forming a paint and an ink, and thus there is a problem that it is difficult to manufacture the paint and the ink.

Furthermore, for example, Japanese Patent Publication No. 1-5438.
No. 6 discloses a method employing “a metal pigment treated with chromic acid”. By employing the metal pigment obtained by this method, the storage stability of the water-based paint and the appearance and adhesion of the coating film when applied to an adherend can be improved to a practical level. . However, since hexavalent chromium must be handled in this method, a safer method is desired from the viewpoint of occupational health and environmental protection.

An object of the present invention is to solve the conventional problems.

An object of the present invention is to produce a metal pigment and a metal pigment which can realize excellent storage stability, excellent adherence to an adherend, and excellent appearance when adhered to an adherend. It is an object of the present invention to provide a method, an auxiliary for producing a metal pigment, an aqueous paint containing a metal pigment, and an ink containing a metal pigment.

[0013]

According to a first aspect of the present invention, there is provided a metal having a powdery metal and an organic sulfur compound covering a surface of the metal. A second means for solving the above-mentioned problem is a metal pigment production method characterized by coating a granular or powdery metal with an organic sulfur compound. The third means is that (1) a higher aliphatic hydrocarbon group-containing sulfur compound or (2) an organic sulfur compound not having the higher aliphatic hydrocarbon group and a higher fatty acid and / or a metal salt of the higher fatty acid. The fourth means for solving the above-mentioned problems is a metal pigment-containing water-based paint characterized by containing the metal pigment of the first means. And the second for solving the above-mentioned problem. Means are metal pigments containing aqueous ink characterized by containing a metallic pigment of the first means.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (1) Metal Pigment The metal pigment of the present invention comprises a powdered metal and an organic sulfur compound covering the surface of the metal.

-Metal-As the metal in the present invention, for example, aluminum,
Examples include at least one metal selected from the group consisting of copper and zinc, and at least two alloys selected from the group consisting of aluminum, copper, and zinc. Examples of the alloy include brass.

The form of the powdered metal in the present invention is not particularly limited, but may take various forms such as a sphere, a rod, an elongated shape, an elliptical sphere, a flat shape, and a non-flat shape.

When the metal pigment of the present invention has a metal powder having a flat shape, when the metal pigment of the present invention is blended in a paint, the paint obtained by applying the paint to an adherend is obtained. The luminance of the film can be increased, and for example, an excellent metallic paint or the like can be obtained.

The flat metal powder has, for example, an average major axis of usually 100 μm or less, preferably 1 to 50 μm.
μm, particularly preferably 3 to 25 μm, and the average thickness is usually at most 5 μm (5 μm or less), preferably at most 2 μm (2 μm or less), and particularly preferably at most 1 μm (1 μm or less). The average aspect ratio (average major axis / average thickness) is usually at least 3 (3 or more), preferably at least 10 (10 or more), and particularly preferably at least 50 (50 or more). . The major axis and thickness of the metal powder can be measured, for example, by sampling a predetermined number of metal powders by direct observation with an electron microscope or the like, observation of an electron micrograph, or the like.

The long diameter of the flat metal powder is 100 μm
When the thickness exceeds 5 μm and the average aspect ratio is less than 3, not only a smooth coating film cannot be obtained even when coating with a paint containing the metal pigment, but also in the case of spray coating, May cause clogging of spray gun.

In the case of non-flat metal powder, the average particle size is preferably 0.1 to 20 μm. This average particle size can be measured in the same manner as described above.

The surface of the metal powder may be directly coated with an organic sulfur compound, or a surface treatment layer may be formed on the surface of the metal powder, and the surface of the protective layer may be coated with an organic sulfur compound. The compound may be coated.

Examples of the surface treatment layer include a layer formed on the surface of a metal powder with a usual pulverization aid used when pulverizing a metal.

Examples of the grinding aid include higher fatty acids such as stearic acid, oleic acid and lauric acid, and higher aliphatic hydrocarbon group-containing compounds such as metal salts of higher fatty acids.

Examples of the higher aliphatic hydrocarbon group include a linear alkyl group having 8 to 22 carbon atoms.

As the metal salt, for example, Ca salt, Z
Groups IIA, IIB, and
Examples include salts of at least one metal selected from the group consisting of Group IIIA.

-Organic sulfur compound- The organic sulfur compound in the present invention covers a part or all of the surface of the metal.

The organic sulfur compound includes, for example, a sulfur compound containing at least a carbon atom, a hydrogen atom, and a sulfur atom in a molecule thereof. Particularly, a thiol compound having a thiol group and a sulfide compound having a sulfide group are included. And a heterocyclic sulfur compound or the like can be suitably used.

Examples of the thiol compound include ethanethiol, octanethiol, ethanedithiol,
Examples thereof include alkyl mercaptans such as propanedithiol, mercaptoethanol, octanol 3-mercaptopropionic acid, and pentaerythritol tetrakis (3-mercaptopropionic acid) and derivatives thereof.

As the sulfide compound, for example,
Examples thereof include sulfide compounds such as propyl sulfide, octyl sulfide, dodecyl thiopropionic acid, lauryl thiopropionic acid, and stearyl thiopropionic acid, and derivatives thereof. Examples of the heterocyclic sulfur compound include benzothiazole, mercaptobenzothiazole, 2,4,6-trimercapto-S-triazine and the like.

As the organic sulfur compound, for example, a sulfur compound containing a higher aliphatic hydrocarbon group containing a higher aliphatic hydrocarbon group is preferable. Examples of the higher aliphatic hydrocarbon group include a linear alkyl group having 8 to 22 carbon atoms.

Examples of the higher aliphatic hydrocarbon group-containing sulfur compound include a higher aliphatic hydrocarbon group-containing thiol compound and a higher aliphatic hydrocarbon group-containing sulfide compound. Examples include higher aliphatic sulfides such as octyl sulfide, and higher aliphatic thiocarboxylic acids such as dodecylthiopropionic acid, laurylthiopropionic acid, and stearylthiopropionic acid.

In the present invention, the organic sulfur compounds may be used alone or in combination of two or more.

The ratio of the organic sulfur compound to the metal in the metal pigment is usually 0.1 to 20 parts by weight, preferably 0.5 to 1 part by weight, per 100 parts by weight of the metal.
0 parts by weight. The content of the organic sulfur compound is 0.1
When the amount is less than 10 parts by weight, the storage stability of the metal pigment-containing aqueous paint and the metal pigment-containing aqueous ink containing the metal pigment may be insufficient, and the content of the organic sulfur compound may be 20 parts by weight. If the amount exceeds the above range, the coating performance of the metal pigment-containing aqueous paint and the metal pigment-containing aqueous ink may be reduced.

-Form of Metal Pigment- The metal pigment comprises a metal powder and an organic sulfur compound which covers a part or the whole of the surface of the metal powder. For convenience, organic solvents and the like may be contained. Therefore, the form of the metal pigment may vary depending on the presence and amount of the organic solvent and the like, or the content of the organic sulfur compound. Therefore, the form of the metal pigment in the present invention may be apparently, for example, in the form of a dry powder or in the form of a paste.

(2) Metal Pigment Production Method and Metal Pigment Production Aid The metal pigment of the present invention can be produced by coating the above-mentioned granular or powdery metal with the above-mentioned organic sulfur compound.

Examples of the metal include the same kind as the metal in the metal pigment. When performing the coating process, the metal as the raw material (hereinafter referred to as “raw metal”
It may be called. ) Is preferably adjusted to be granular or powdery. There is no particular limitation on the particle size of the raw metal, and it can be appropriately determined according to the scale of the apparatus for performing the pulverizing treatment.

The organic sulfur compound is as described above.

The coating treatment includes (1) pulverizing and kneading a raw material metal and an organic sulfur compound adjusted to be granular or powdery, and (2) adjusting to a particle size similar to that of the metal powder in the metal pigment in the present invention. Kneading the resulting raw metal with an organic sulfur compound may be mentioned.

The raw material metal to be subjected to the pulverizing and kneading treatment of the above (1) includes a distillation metal powder obtained by a distillation method, an atomized metal powder obtained by an atomization method, and a kneading treatment of a kneading treatment by a ball kneader. Examples include metal powder, pulverized metal powder that has been pulverized by a pulverizer, and spread metal powder that has been subjected to spread processing by a spreader. Preferred raw material metals include distilled metal powder obtained by a distillation method, atomized metal powder obtained by an atomization method, and the like.

Regardless of which method the raw metal is prepared, the raw metal to be subjected to the above-mentioned pulverizing and kneading treatment (1) has a particle size of 500 μm or less, preferably 200 μm.
It is preferably adjusted as follows. When the raw material particles whose particle size is adjusted in advance are employed, the coating treatment with the organic sulfur compound can be efficiently performed.

In the pulverizing and kneading treatment of the above (1), the raw metal is pulverized during the treatment and adjusted to the particle diameter of the metal in the metal pigment according to the present invention, and at the same time, the surface of the metal powder is a sulfur organic compound. Covered.

As the pulverizing and kneading apparatus for the pulverizing and kneading treatment (1), for example, a ball-type kneading machine can be used. Examples of the ball-type kneader include internal rotating mills such as the above-mentioned attritor, sand mill, and sand grinder, rotary mills such as a dry ball mill and a wet ball mill, vibration mills, and stamp mills.

The conditions for the pulverization and kneading are determined by an engineer belonging to this technical field by repeating trial and error of the operation of the pulverization and kneading apparatus according to the particle size of the raw metal so as to obtain the metal pigment according to the present invention. Can be easily determined.

However, as for the mixing ratio of the raw material metal and the organic sulfur compound, the amount of the organic sulfur compound relative to 100 parts by weight of the metal is usually 0.1 to 20 parts by weight, preferably 0.5 to 10 parts by weight. is there. When the compounding amount of the organic sulfur compound with respect to the raw material metal is within the above range, the metal pigment according to the present invention can be produced well.

In the pulverizing and kneading treatment, the obtained metal pigment can be formed into a flat shape by a specific organic sulfur compound among the organic sulfur compounds used.

Examples of the specific organic sulfur compound include an organic sulfur compound having a higher aliphatic hydrocarbon group, that is, a sulfur compound having a higher aliphatic hydrocarbon group. The sulfur compound containing a higher aliphatic hydrocarbon group is as described above.

The organic sulfur compound having no higher aliphatic hydrocarbon group is obtained by pulverizing and kneading the raw material metal together with the higher fatty acid and / or the metal salt of the higher fatty acid to obtain a flat metal. Pigments can be produced.

Examples of the organic sulfur compound having no higher aliphatic hydrocarbon group include thiol compounds such as ethanethiol, octanethiol, ethanedithiol, propanedithiol, mercaptoethanol, and octanol-3-mercaptopropionic acid. And thiol compounds such as alkyl mercaptans and derivatives thereof such as pentaerythritol tetrakis (3-mercaptopropionic acid), and heterocycles such as benzothiazole, mercaptobenzothiazole and 2,4,6-trimercapto-S-triazine. Examples thereof include sulfur compounds and sulfide compounds such as propyl sulfide and octyl sulfide.

The higher fatty acids include stearic acid,
Higher fatty acids such as oleic acid and lauric acid can be mentioned. As the higher aliphatic hydrocarbon group, for example,
Examples thereof include a straight-chain alkyl group having 8 to 22 carbon atoms.

The metal salts of the higher fatty acids include, for example, Group IIA and Group IIA of the periodic table such as Ca salts, Zn salts and Al salts.
Examples include salts of at least one metal selected from the group consisting of Group IIB and Group IIIA.

The higher fatty acid and / or the metal salt of the higher fatty acid can be used together with the higher aliphatic hydrocarbon group-containing sulfur compound.

The (1) higher aliphatic hydrocarbon group-containing sulfur compound, and (2) the organic sulfur compound having no higher aliphatic hydrocarbon group and the higher fatty acid and / or the metal salt of the higher fatty acid are crushed into In the kneading treatment, an effect of flattening the metal powder in the process of pulverizing the raw metal and an effect of coordinating with the surface of the metal powder to prevent contact of moisture and moisture with the metal surface are exhibited.

Accordingly, the (1) higher aliphatic hydrocarbon group-containing sulfur compound, and (2) the organic sulfur compound having no higher aliphatic hydrocarbon group and the higher fatty acid and / or the metal salt of the higher fatty acid are as follows: And an excellent auxiliary for producing a metal pigment according to the present invention.

The amount of the above-mentioned higher fatty acid and / or metal salt of the higher fatty acid to be used is usually 100 parts by weight of the raw material metal.
20 parts by weight or less.

The pulverizing and kneading treatment can further use a pulverizing auxiliary commonly used for pulverizing metal powder, and can be carried out in the presence of an inert organic solvent and / or an inert gas.

Examples of the grinding aid include fatty acids, aliphatic amines, fatty acid amides, aliphatic alcohols and the like.

Examples of the inert organic solvent include aliphatic hydrocarbons such as mineral spirits.

In the kneading treatment of the above (2), the metal pigment is a flat metal powder adjusted to a predetermined long diameter, a thickness and an aspect ratio or a non-flat metal powder adjusted to a predetermined average particle diameter and a metal powder composition. The compound, the organic sulfur compound or the metal pigment-producing auxiliary according to the present invention, and, if necessary, the pulverizing auxiliary are kneaded in the presence of an inert organic solvent and / or an inert gas.

Examples of the kneading machine include a usual device such as a Henschel mixer.

In each of the pulverizing and kneading treatment of the above (1) and the kneading treatment of the above (2), various other additives may be added as long as the object of the present invention is not impaired.

(3) Water-based paint containing metal pigment The water-based paint containing metal pigment of the present invention contains the above-mentioned metal pigment.

The metal pigment-containing water-based paint can be produced, for example, by blending the metal pigment, a paint resin, and an aqueous paint solvent by a conventionally known coating method.

As the paint resin, for example, a water-based paint resin, a resin conventionally used as a metallic paint resin, or the like can be used. Specifically, as the resin for the coating, for example, acrylic resin, alkyd resin, oil-free alkyd resin, vinyl chloride resin, urethane resin, melamine resin, polyester resin,
Organic resins such as urea resin, cellulose resin, epoxy resin and silicone resin, and inorganic resins such as sodium silicate, potassium silicate and ethyl silicate can be exemplified. These may be used alone or in combination of two or more.

The solvent for the water-based paint includes, for example,
Examples include water, alcohol solvents such as isopropyl alcohol, cellosolve solvents such as butyl cellosolve, and glycol solvents such as ethylene glycol.

In the water-based paint containing a metal pigment, for example,
Additives for coatings such as organic solvents, pigments, dyes, wetting agents, dispersants, anti-segregation agents, leveling agents, anti-skinning agents, and antifoaming agents which are conventionally known in the technical field of coatings can be added.

The mixing ratio of the metal pigment in the metal pigment-containing water-based paint can be appropriately determined according to the characteristics of the paint resin.

The mixing ratio of the coating solvent in the metal pigment-containing water-based coating is usually 0 to 50% by weight, preferably 0 to 30% by weight, when the total amount of the metal pigment-containing water-based coating is 100. .

The mixing ratio of the paint additive in the metal pigment-containing water-based paint is generally 0 to 50% by weight, preferably 0 to 20% by weight, when the total amount of the metal pigment-containing water-based paint is 100. is there.

The metal pigment of the present invention can exhibit extremely excellent storage stability in a water-based paint. By applying this water-based paint to an adherend, a coating having excellent appearance and excellent adhesion can be obtained. A film can be realized, and even when the metal pigment is blended in a solvent-based paint (also referred to as “non-aqueous paint”), it is excellent by applying this solvent-based paint to an adherend. A coating film having a good appearance and excellent adhesion can be realized.

(4) Water-based ink containing metal pigment The water-based ink containing metal pigment of the present invention contains the above-mentioned metal pigment.

The aqueous ink containing a metal pigment is, for example,
It can be produced by blending the metal pigment, the resin for ink, and the aqueous solvent for ink by a conventionally known ink-forming method.

Examples of the ink resin include a water-based ink resin such as a maleic acid resin, an acrylic resin, and shellac, a rosin-modified phenol resin, and a petroleum resin.
Alkyd resins, polyamide resins, vinyl resins, nitrocellulose resins and the like can be mentioned. These are 1
The species may be used alone, or two or more species may be used in combination.

Examples of the aqueous solvent for ink include, for example,
Examples include water, alcohol solvents such as isopropyl alcohol, cellosolve solvents such as butyl cellosolve, and glycol solvents such as ethylene glycol.

The above-mentioned water-based ink containing a metal pigment includes, for example, organic solvents, pigments, dyes, wetting agents, dispersants, anti-separation agents, leveling agents, anti-skinning agents, defoaming agents which are conventionally known in the art of inks. And ink additives such as agents, waxes, silicone, starch, metal soap, and drying oil.

The metal pigment of the present invention can exhibit extremely excellent storage stability in an aqueous ink. By printing this aqueous ink on an adherend, a print having excellent appearance and excellent adhesion can be obtained. An image can be realized. Even when the metal pigment is mixed with, for example, a solvent-based ink (also referred to as a “non-aqueous paint”) or a drying oil-based ink, the solvent-based ink, By printing an oil-based ink or the like on the adherend, a printed image having excellent appearance and excellent adhesion can be realized.

Example 1 Atomized zinc powder (average particle size: 100 μm) was placed in an attritor having a capacity of 5 liters.
kg, 40 g of 3-stearylthiopropionic acid, 1 kg of mineral spirit, and hard ball 10 k having a diameter of 10 mm
g, this attritor was operated at 200 rpm for 20 hours, and then the mineral spirit was separated by filtration to obtain a zinc powder-containing composition. This zinc powder-containing composition was
After heating at 05 ° C for 3 hours, the heating residue is 9
It was 0% by weight. When the obtained zinc powder-containing composition was observed with an electron microscope, the particle shape was flat with an average major axis of 10 μm, an average thickness of 0.1 μm, and an average aspect ratio of 100. Using this as a sample, an evaluation test described later was performed, and the results are shown in Table 1.

Example 2 A zinc powder-containing material was prepared in the same manner as in Example 1 except that 40 g of 3-palmitylthiopropionic acid was used instead of 40 g of 3-stearylthiopropionic acid. A composition was obtained. The heating residue after heating this zinc powder-containing composition at 105 ° C. for 3 hours was 90% by weight. Observation of the obtained zinc powder-containing composition with an electron microscope revealed that the particles had a flat shape having an average major axis of 5 μm, an average thickness of 1 μm, and an average aspect ratio of 5. Using this as a sample, an evaluation test described later was performed, and the results are shown in Table 1.

(Example 3) Instead of 40 g of 3-stearylthiopropionic acid in Example 1, pentaerythritol tetrakis (3-mercaptopropionic acid) 20 was used.
Example 1 except that g and 20 g of stearic acid were used.
The same operation as described above was performed to obtain a zinc powder-containing composition. The heating residue after heating this zinc powder-containing composition at 105 ° C. for 3 hours was 90% by weight. When the obtained zinc powder-containing composition was observed with an electron microscope, the particle shape was found to have an average major axis of 12 μm and an average thickness of 0.2 μm.
μm and a flat shape having an average aspect ratio of 60. Using this as a sample, an evaluation test described later was performed, and the results are shown in Table 1.

Example 4 A zinc powder-containing composition was obtained in the same manner as in Example 1, except that 1 kg of mineral spirit was not used. After heating this zinc powder-containing composition at 105 ° C. for 3 hours, the heating residue was 96% by weight. When the obtained zinc powder-containing composition was observed with an electron microscope, the particle shape was such that the average major axis was 6 μm and the average thickness was 0.1 μm.
m and a flat shape having an average aspect ratio of 60. Using this as a sample, an evaluation test described later was performed, and the results are shown in Table 1.

Example 5 In a 20-liter capacity ball mill, 42 kg of steel balls having a diameter of 50 mm, 1 kg of atomized aluminum powder (average particle size: 20 μm),
5 kg of mineral spirit and 20 g of 3-stearylthiopropionic acid were added, and this ball mill was
After operating at pm for 10 hours, the mineral spirit was separated by filtration to obtain an aluminum powder-containing composition. The heating residue after heating this aluminum powder-containing composition at 105 ° C. for 3 hours was 80% by weight. When the obtained aluminum powder-containing composition was observed with an electron microscope, the particle shape was flat, with an average major axis of 10 μm, an average thickness of 0.1 μm, and an average aspect ratio of 100. Using this as a sample, an evaluation test described later was performed, and the results are shown in Table 1.

Comparative Example 1 A zinc powder was obtained in the same manner as in Example 1, except that 40 g of 3-stearylthiopropionic acid was not used.
The heating residue after heating this zinc powder at 105 ° C. for 3 hours was 90% by weight. Observation of the obtained zinc powder with an electron microscope revealed that the particles had a flat shape with an average major axis of 3 μm, an average thickness of 2 μm, and an average aspect ratio of 1.5. Using this as a sample, an evaluation test described later was performed, and the results are shown in Table 1.

Comparative Example 2 In place of 40 g of 3-stearylthiopropionic acid in Example 1, stearic acid 4
A zinc powder-containing composition was obtained by performing the same operation as in Example 1 except that 0 g was used. The heating residue after heating this zinc powder-containing composition at 105 ° C. for 3 hours was 90% by weight. When the obtained zinc powder-containing composition was observed with an electron microscope, the particle shape was flat with an average major axis of 10 μm, an average thickness of 0.1 μm, and an average aspect ratio of 100. Using this as a sample, an evaluation test described later was performed, and the results are shown in Table 1.

Comparative Example 3 In place of 20 g of 3-stearylthiopropionic acid in Example 5, oleic acid 20
Except for using g, the same operation as in Example 1 was performed to obtain an aluminum powder-containing composition. The heating residue after heating this aluminum powder-containing composition at 105 ° C. for 3 hours was 80% by weight. When the obtained aluminum powder-containing composition was observed with an electron microscope,
The particle shape has an average major axis of 10 μm and an average thickness of 0.1 μm.
It was flat with an average aspect ratio of 100 μm.
Using this as a sample, an evaluation test described later was performed, and the results are shown in Table 1.

-Evaluation Test- (1) Water Stability Evaluation Test 20 g of a sample was placed in a 200 ml Erlenmeyer flask.
And a nonionic surfactant (“Dipanol LS-10” manufactured by NOF Corporation) is placed in the flask.
0 ") and 0.5 g of pure water. A rubber stopper with a glass tube was attached to the mouth of the flask, and a polyethylene tube was attached to the glass tube. The inside of the flask was stirred by a magnetic stirrer, and hydrogen generated in the flask was collected by the water collecting method through the polyethylene tube. The amount of collected gas at the time when 3 hours had passed since the start of stirring was read and evaluated based on the following criteria.

0.5 cc / g or less ··· 0.5 to 5 cc / g ···· More than 5 cc ··· × (2) Evaluation test of paint and coating film performance An aqueous paint having the following composition was prepared, and (2A) the storage stability of the paint, (2B) the appearance of the coating film, and (2C) the adhesion of the coating film were evaluated.

(Water-based paint) Sample: 20 parts Water-soluble acrylic resin (“Julima AT-” manufactured by Nippon Pure Chemical Industries, Ltd.) 613 ") (heating residue 50% by weight) ... 300 parts water-soluble melamine resin (" Sumimar 50W "manufactured by Sumitomo Chemical Co., Ltd.) (heating residue 80 weight 100 parts Pure water 200 parts (2A) Storage stability of paint 200 ml Water-based paint 5 in Ehrenmeyer flask
0 g was collected. A rubber stopper with a glass tube was attached to the mouth of the flask, and a polyethylene tube was attached to the glass tube. The inside of the flask was stirred with a magnetic stirrer, and the hydrogen generated in the flask was collected by the water collecting method through the polyethylene tube.
The amount of collected gas at the time when 3 hours had passed since the start of stirring was read, and evaluated based on the same criteria as in the water stability evaluation test.

(2B) Appearance of coating film An aqueous paint was sprayed onto the degreased polished steel sheet to obtain a coated steel sheet having a coating film having a dry film thickness of 15 to 20 µm. The appearance of this coating film was visually evaluated according to the following criteria.

There is no dullness and there is a metallic luster ..... 〇 Slightly dull ..... △. 2C) Adhesion of coating film The coated steel plate was immersed in warm water of 60 ° C for 1 hour, and then left at room temperature for 24 hours. A cross-cut test is performed on the coating film on the coated steel sheet (a cellophane tape peeling test is performed by attaching a cellophane tape to the coating film with a cut-like cut and peeling off the cellophane tape), and visually observe the peeling state of the coating film. And evaluated according to the following criteria.

The area of the coating film with the cross cut is
The target coating film to be tested was used, and the coating film retention of the target coating film was determined.

Coating retention (%) = {(target coating area-defective coating area) / target coating area} × 100 Coating retention 99% or more (good) ... Retention 90-99% (slightly poor) ··· Less than 90% coating retention (bad) ··· ×

[0091]

[Table 1]

[0092]

According to the present invention, excellent storage stability and
A metal pigment capable of realizing excellent adhesion to an adherend and excellent appearance when adhered to an adherend, a method for producing a metal pigment, an auxiliary for producing a metal pigment, an aqueous paint containing a metal pigment, and A metal pigment-containing ink can be provided.

In particular, the metal pigment-containing water-based paint imparts excellent water resistance to the adherends because, for example, the storage stability as the paint is excellent and the obtained coating film has excellent adhesion. In addition, the industrial value is extremely high since the organic sulfur compound can be effectively used.

Claims (5)

[Claims] 1. A metal pigment comprising a powdered metal and an organic sulfur compound covering the surface of the metal. 2. A method for producing a metal pigment, comprising coating a granular or powdery metal with an organic sulfur compound. 3. It contains (1) a higher aliphatic hydrocarbon group-containing sulfur compound or (2) an organic sulfur compound not having the higher aliphatic hydrocarbon group and a higher fatty acid and / or a metal salt of a higher fatty acid. An auxiliary agent for producing metal pigments. 4. An aqueous paint containing a metal pigment, comprising the metal pigment according to claim 1. 5. An aqueous ink containing a metal pigment, which comprises the metal pigment according to claim 1.