JPH06322287A - Surface-treated composite aluminum powder and preparation of surface-treated composite aluminum flake using it - Google Patents

Abstract

PURPOSE:To provide a method for preparing a highly lustrous composite aluminum flake with excellent water resistance and agglomeration resistance and being useful for a pigment for coating. CONSTITUTION:A composite aluminum flake is prepd. by a method wherein the surface of approximately spherical aluminum particle is treated with a treating fluid contg. at least one kind of metal ions such as Zi, Ti or Cr and, if necessary, P ion to form a film layer contg. the elements and this composite particle is flattened into a scaly shape by grinding and rolling.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a composite aluminum powder and a method for producing a composite aluminum flake using the same. More specifically, the present invention relates to a composite aluminum powder having a coating layer containing Zr, Ti, and / or Cr, and
By using it, it is useful as a metallic paint, a printing ink, and a pigment for kneading plastics, and has unique glossiness, excellent water resistance, and hydrogen gas generation resistance.
And a storage stability of the composite aluminum flakes.

[0002]

2. Description of the Related Art Conventionally, aluminum pigments have been used for the purpose of obtaining a luster peculiar to metal, that is, a so-called metallic feeling, for coating paints, printing inks, and plastics. Aluminum pigments used as metallic pigments are scaly ones generally called aluminum flakes. As a method for producing such aluminum flakes, aluminum powder (atomized powder,
On the surface of shredder powder, etc.), suppressing its surface activity,
For the purpose of preventing agglomeration during grinding, a fatty acid such as stearic acid or oleic acid, an aliphatic amine, or a grinding aid made of other fatty acid derivative or the like is adsorbed, and a dry method (stamp mill method, hametag method), Alternatively, a method of crushing (expanding) by a known method such as a wet method (Hall method) is known.

Recently, in order to save resources and reduce pollution, paint systems are becoming water-based. However, the aluminum flakes obtained by the conventional method described above are treated with a surfactant. When dispersed in the water-based paint, there is a risk that hydrogen gas is generated due to the reaction between the water in the paint and the aluminum flakes to deform the container or cause an explosion. In addition, during the reaction, the metallic luster of the aluminum flakes is remarkably reduced, and the aluminum flakes discolor to black (so-called black discoloration phenomenon), so that there is a problem that the commercial value is lost. In particular, this hydrogen gas generation reaction is promoted by the presence of an acid or alkali component, so in a water-based coating containing a water-soluble resin containing an alkali component such as amine, or an aqueous emulsion resin, aluminum flakes are used as a pigment. It was difficult to use.

The aluminum flakes also react with the resin component contained in the coating material to form a gel, or react with an organic pigment to cause a seeding phenomenon (a phenomenon in which color fading or the coating material agglomerates to form spots). There is also a problem in that, when the coating film is formed, the weather resistance is inferior, the coating film is deteriorated, and the metallic feeling after exposure to the outdoors is deteriorated. It is believed that these problems are due to the fact that aluminum is a very active metal.

Therefore, various treatments and manufacturing techniques for inactivating the surface of the aluminum pigment have been proposed. For example,
JP-B-34-9729 and JP-A-63-54
Japanese Patent No. 475 discloses that the surface of aluminum can be inactivated and the reaction with water can be suppressed by contacting the surface of aluminum with inorganic phosphoric acid. Further, JP-A-61-296072 and JP-A-60-15
No. 466, No. 61-47771, No. 57-16066, and No. 60-8057 discloses that a specific organic phosphate ester is adsorbed on a metal surface such as aluminum. It is disclosed that the reaction between the metal powder and water can be suppressed and the aluminum pigment can be stably present in the water-based paint. Furthermore, in JP-A-3-74472, excellent water resistance is obtained by aging aluminum in the presence of a phosphoric acid ester and an organic solvent at an appropriate temperature and time to form a uniform and stable oxide film on the aluminum surface. Is disclosed. However, in any of these methods, the effect of suppressing hydrogen gas generation in the water-based paint during storage is still insufficient, so that the aluminum surface discolors black, impairing the glossiness peculiar to metallic pigments. Was not resolved.

Japanese Patent Publication No. 59-15153 discloses that dimer acid can be used as a grinding aid or added after grinding to suppress generation of hydrogen gas when an aluminum pigment is dispersed in water. However, even in this case, the effect of suppressing the generation of hydrogen gas in the water-based paint is still insufficient, and these treatments cause the aluminum pigment to change its color tone, and the pigment does not aggregate when it is made into paint. However, we could not obtain a product with satisfactory quality.

Japanese Patent Publication No. 1-54386 discloses that an aluminum flake pigment surface is passivated by using an aqueous solution containing chromic acid and a water-soluble glycol ether and / or a water-soluble glycol to suppress the activity of aluminum. Is disclosed, and further, Japanese Patent Laid-Open No. 2-6
Japanese Patent Publication No. 0972 discloses that an aluminum surface can be inactivated by subjecting an aluminum pigment to a chromate treatment. However, these methods can considerably suppress the hydrogen gas generation described above, but due to the use of chromic acid, the color tone of the aluminum pigment is changed to a golden color, and there is a problem such as impairing the glossiness peculiar to the metallic pigment. I have it.

[0008]

DISCLOSURE OF THE INVENTION The present invention solves the problems of glossiness, water resistance, weather resistance and stability in paint of the above-mentioned prior art, and the composite aluminum flakes excellent in these performances and their production. It is intended to provide a method.

[0009]

As a result of intensive studies, the inventors of the present invention have found that the surface of a nearly spherical aluminum powder contains one or more metals of Ti, Zr, and Cr, and if necessary, By using a composite aluminum powder with a coating layer containing phosphorus, excellent water resistance without sacrificing the metallic luster characteristic of aluminum,
It was found that a novel surface-treated aluminum flake having hydrogen gas generation-preventing property and storage stability can be produced, and the present invention has been completed.

The composite aluminum powder according to the present invention has substantially spherical aluminum particles and is formed on the surface of the aluminum particles.
And a coating film layer containing at least one compound containing at least one metal selected from Zr, Ti and Cr.

The coating layer of the composite aluminum powder of the present invention preferably contains phosphorus. Further, the coating layer of the composite aluminum powder of the present invention is 1 to 1 g per 1 g of the composite aluminum flake.
It is preferable to include 100 mg of the metal and 1 to 100 mg of phosphorus.

The composite aluminum powder of the present invention is crushed and spread to have an average diameter of 5 to 70 μm and 0.0
Composite aluminum flakes having a thickness of 5 to 2 μm can be obtained.

That is, in the method for producing composite aluminum flakes of the present invention, aluminum particles are mixed with Zr ions, T
At least 1 selected from i ion and Cr ion
By contacting with an aqueous treatment liquid containing a seed, thereby, on the surface of the aluminum particles, to form a coating layer containing a compound of the metal to prepare a composite aluminum powder, the composite aluminum powder is subjected to crushing and spreading treatment. Give,
It is characterized by forming composite aluminum flakes.

In the method of the present invention, the aqueous treatment liquid is
It is preferable that a coating layer containing orthophosphate ions and thereby containing at least one compound containing the metal and phosphorus is formed on the surface of the aluminum particles.

In the method of the present invention, the crushing and spreading treatment of the composite aluminum particles is carried out by using saturated fatty acid, unsaturated fatty acid,
It is preferable to carry out the treatment in the presence of a grinding aid comprising at least one selected from these fatty acid derivatives and organic phosphates.

In the method of the present invention, the organic phosphate ester is represented by the following formula (I): OP (OR) _n (OZ) _3-n (I) [wherein, in the above formula (I), R is carbon Represents an alkyl group, an alkenyl group, or an aryl group of the formulas 1 to 24, Z
Represents a hydrogen atom or a chemical species that neutralizes an acid phosphate, n represents an integer 1, 2, or 3, and when n = 2 or 3, 2 or 3 Rs are They may be the same as each other or different from each other].

In the method of the present invention, the aqueous treatment liquid is
It preferably has a pH of 1-4.

[0018]

The aqueous treatment liquid used in the present invention is Zr, Ti.
And a metal ion consisting of one or more selected from Cr ions and, if necessary, an orthophosphate ion. To supply these ions,
Although not particularly limited, examples of the Zr ion source include zirconium chloride, zirconium nitrate, zirconium sulfate, zirconyl chloride, zirconyl nitrate, zirconyl sulfate, zirconyl acetate, zirconium fluoride, ammonium zirconium fluoride, and zirconium fluoride. An alkali metal salt of an acid or the like can be used.

As the Ti ion source, a water-soluble salt such as titanyl sulfate, titanium tetrachloride, fluorotitanic acid, an ammonium salt of fluorotitanic acid, an alkali metal salt of fluorotitanic acid, fluorotitanic acid, or fluorofluoride is used. An ammonium salt of titanium acid, an alkali metal salt of fluorotitanic acid, or the like can be used.

As the Cr ion source, water-soluble trivalent chromium salts such as chromium nitrate, chromium sulfate, chromium chloride, chromium fluoride, and chromium diphosphate, and chromic acid or dichromic acid are known methods. Chromate, chromic acid, dichromic acid, ammonium salt of dichromic acid, hexavalent chromium salt such as alkali metal salt of chromic acid, and the like, which can be obtained by reduction with.

Examples of the orthophosphate ion source include orthophosphoric acid, ammonium salts of phosphoric acid, alkali metal salts of phosphoric acid and the like.

The pH of the treatment aqueous solution is not particularly limited, but it is preferably adjusted to 1 to 4 in terms of reactivity and economy. That is, if the pH is less than 1, the reaction of metal ions and phosphate ions with respect to the pigment is insufficient, and if it exceeds 4, unnecessary precipitation is likely to occur, resulting in waste of chemicals and is not economical. . In order to adjust the pH to 1 to 4, inorganic acids such as phosphoric acid, sulfuric acid, nitric acid, hydrofluoric acid, and hydrochloric acid, and carboxylic acids such as formic acid, acetic acid, oxalic acid, and benzoic acid, and tartaric acid, citric acid, Organic acids such as oxycarboxylic acids of lactic acid, phenols such as carboxylic acid, tannic acid and the like can be used.

Further, in order to improve the stability of the treatment aqueous solution (prevention of precipitation of metal ions), a complexing agent composed of an organic compound having 6 or less carbon atoms may be added to the treatment aqueous solution. Examples of such complexing agents include polyhydroxy compounds such as gluconic acid, gluconate, sorbitol, mannitol, dextrose, ethylene glycol, and glycerin.

The total content of one or more metal ions selected from Zr, Ti, and Cr in the treatment aqueous solution is preferably 0.1 to 50 g / liter, and the orthophosphate ion content is 0.15 g / liter. Content is 0.1-50g
/ Liter is preferable. When the content of each of these ions is less than the above lower limit value, a sufficient amount of film cannot be obtained to obtain a desired effect, and when the amount exceeds these upper limits, the film forming reaction is saturated, which is economically disadvantageous. Is.

In the film formed on the surface of aluminum particles, Zr, Ti, and
The content of one or more metal compounds selected from Cr and Cr is preferably 1 to 100 mg in terms of metal, and the content of phosphoric acid is 1 to 100 mg in terms of P.
Is preferred. If it is less than the above lower limit, the desired effect cannot be obtained, and if it exceeds the upper limit, the effect of improving the water resistance is saturated, and conversely, the gloss is reduced and the color tone is changed, which is not preferable.

Next, the method for producing the surface-treated composite aluminum flakes of the present invention will be specifically described.
Aqueous acidic treatment solution of pH 1 to 4 prepared as described above,
Heated to a temperature of 100 ° C. or less, and a powder composed of substantially spherical aluminum particles (atomized powder, shredder powder, etc., having an average particle size of 1 to 50 μm)
Throw in. The amount of the aluminum powder to be added may be an amount capable of uniformly dispersing the aluminum powder in the treatment liquid, and generally 3 to 30% by weight based on the weight of the treatment aqueous solution is suitable. After charging, aluminum powder is uniformly dispersed in the treatment liquid, and Zr, Ti, C
A coating layer containing at least one metal selected from r and at least one compound further containing phosphorus if necessary is formed. After the aluminum powder is added to the aqueous treatment liquid, the required treatment liquid temperature and treatment time are appropriately determined depending on industrial profitability and equipment specifications.

Next, the surface-coated composite aluminum powder is collected by filtration, washed with water, and then dried at a temperature of 150 ° C. or lower.

The composite aluminum powder thus prepared is subjected to a crushing and spreading step. This crushing and spreading is to apply a force for expanding and refining the composite aluminum, for example, a stamp mill method,
By using a dry method such as the HAMETAG method or a wet method such as a Hall method, the approximately spherical composite aluminum particles are flattened into scales, and the aluminum composite particles are torn and finely divided. By this crushing and spreading, from the almost spherical aluminum particles having an average particle diameter of 1 to 50 μm, an average diameter of 5 to 70 μm
Flake-like flakes having a thickness of 0.05 to 2 μm are formed.

The surface of the aluminum flake particles obtained by the pulverization and spreading has a total amount of 1 to 100 mg of metal selected from Zr, Ti, and Cr per 1 g of aluminum flake, It is coated with a film containing 1 to 100 mg of phosphorus.

The composite aluminum flakes produced by such a method of the present invention have excellent water resistance (hydrogen gas generation-preventing property, storage stability) without impairing the metallic luster characteristic of aluminum pigments.

Further, in the method of the present invention, when the composite aluminum powder is crushed and spread to form water resistant composite aluminum flakes, 0.1 to 20 parts by weight per 100 parts by weight of the composite aluminum powder is used as a grinding aid. Parts, preferably 0.1 to 10 parts by weight of saturated or unsaturated fatty acids such as stearic acid and oleic acid, aliphatic amines (preferably having 6 to 18 carbon atoms), or other fatty acid derivatives, or phosphoric acid. Alcohol,
By using one kind or two or more kinds selected from organic phosphates such as mono-, di-, and triesters with phenols and the like, surface-treated aluminum flakes having further excellent water resistance can be obtained.

The organic phosphoric acid ester used here is not particularly limited, but examples thereof include the organic phosphoric acid ester represented by the following chemical formula (I). OP (OR) _n (OZ) _3-n [wherein, in the formula (I), Z is a hydrogen atom or a chemical species that neutralizes the acid phosphate, such as Li, Na, K, ammonium, triethylamine, and morpholine. Inorganic and organic basic species such as, dibutylamine, monoethanolamine, diethanolamine and triethanolamine, with R being 1-24, preferably 6-18.
An alkyl group or alkenyl group having 4 carbon atoms,
Or an aryl group and represents an integer of n = 1, 2 or 3, and when n = 2 or 3, two or three R groups may be the same or different from each other. Good. ]

Such an organic phosphate ester is not only used as a grinding aid, but is also added when the composite aluminum flakes obtained from the composite aluminum particles having a coating layer of the present invention are added to the water-based paint when kneading. Is obtained.

The form of the film formed and adhered on the surface of the aluminum flakes by the method of the present invention is amorphous, and therefore cannot be identified. However, compounds of Zr, Ti and Cr,
In particular, when phosphorus is contained, it is presumed that phosphate compounds of these metals are predominant. In addition, this film is a film that is hardly soluble in water generated in an acidic aqueous solution, and since aluminum flakes are covered by this film, the activity of aluminum in the water-based paint is suppressed, and practical water resistance ( Gas resistance, storage stability, etc.) are considered to have been obtained.

On the other hand, the appearance of the film may be affected by the film formation such as a decrease in gloss and discoloration, but the aluminum flakes of the present invention have no such effect. The reason for this is that the Zr, Ti, and Cr compounds, especially the phosphate compound coating is colorless and transparent, and that the coating layer is formed on the aluminum particles by the method of the present invention, and then a known method is used. When crushed (expanded) by crushing (expanding), it is considered that the aluminum particles are expanded and the film is expanded at the same time, and a uniform film layer is formed on the surface of the obtained composite aluminum flake pigment.

Further, the water resistance is further imparted by using the organic phosphoric acid ester as the grinding aid,
It is presumed that the water resistance is further improved by adsorbing these grinding aids on the active sites of aluminum that the metal compound film of the present invention could not suppress.

[0037]

EXAMPLES The effects of the present invention will be described more specifically with reference to the following examples, but the present invention is not limited thereto.

Example 1 Treatment liquid A (0.45 g / liter of fluorozirconic acid in terms of zirconium, 0.48 g / liter of phosphoric acid, 0.33 g / liter of sodium gluconate, 1.9 g / nitric acid) 1 liter adjusted to pH 3.0 with aqueous ammonia) 2 liters are placed in a glass beaker and kept at 40 ° C.
Then, 110 g of aluminum atomized powder having an average particle size of 10 μm was charged and dispersed. After completely dispersed, 4
Hold at 0 ° C for 30 minutes. Thereafter, the obtained composite aluminum powder was collected by filtration, washed with water and methanol, and dried at 110 ° C. for 2 hours. To 100 g of the composite aluminum atomized powder thus obtained, 6 g of stearic acid and 200 ml of mineral spirit were added and kneaded, and this was crushed and spread by a ball mill for 3 hours (Hall method). After crushing, the slurry is poured out with mineral spirits and passed through a 325 mesh filter, followed by solid content separation,
An aluminum flake cake having a solid content of 95% was obtained. The resulting composite aluminum flakes have a thickness of about 0.5μ.
m, the average diameter was about 18 μm, and Zr and P were quantified by using XRF (fluorescent X-ray analyzer). As a result, Zr of 7.2 mg and P of 1.5 mg were attached to 1 g of the composite aluminum flake. It was

Example 2 Treatment liquid B (using an aqueous solution of chromium biphosphate, diluted with deionized water to 4 g / liter in terms of Cr. PH is 1.5.
2 liters) was placed in a glass beaker, and 110 g of aluminum atomized powder having an average particle size of 15 μm was added and dispersed. After being completely dispersed, it was heated to 70 ° C. and kept at that temperature for 30 minutes. Then, the surface-treated composite aluminum powder was collected by filtration, washed with water and washed with methanol,
It was dried at ° C for 2 hours. 100 g of the composite aluminum atomized powder thus obtained was mixed with 6 parts of stearic acid.
g, 200 ml of mineral spirits were added, kneaded, and crushed and spread by a ball mill for 2 hours and 30 minutes (Hall method). After crushing, drain the slurry with mineral spirits, 3
After passing through a 25-mesh filter, solid content was separated to obtain an aluminum flake cake having a solid content of 96%. The obtained composite aluminum flakes have a thickness of about 0.7.
The average diameter was about 28 μm, and Cr and P were quantified using XRF (fluorescent X-ray analyzer). As a result, 1 mg of composite aluminum flake had 55 mg of Cr and 2 P.
0.2 mg was attached.

Example 3 Treatment liquid C (an aqueous solution containing zirconium ammonium fluoride in an amount of 3.9 g / liter in terms of Zr, chromium fluoride in an amount of 5 g / liter in terms of chromium and 5.2 g / liter of monosodium phosphate). To the glass beaker, 2 liters of nitric acid was added to adjust the pH to 1.8) and the mixture was heated to 75 ° C. Aluminum atomized powder 1 with an average particle size of 20 μm
10 g was added and dispersed. After completely dispersing, the state was maintained for 60 minutes. Then, the surface-treated composite aluminum powder was collected by filtration, washed with water and washed with methanol, and then at 110 ° C for 2
Dried for hours. To 100 g of the composite aluminum atomized powder thus obtained, 6 g of oleic acid and 200 ml of mineral spirit were added, kneaded, and crushed and spread for 3 hours by a ball mill (Hall method). After crushing, the slurry was poured out with mineral spirits and passed through a 325-mesh filter, followed by solid content separation to obtain a solid content of 95.
% Aluminum flake cake was obtained. The obtained composite aluminum flakes had a thickness of about 0.6 μm and an average diameter of about 47 μm, and when Zr, Cr and P were quantified using XRF (fluorescent X-ray analyzer), 1 g of composite aluminum flakes Zr 7.1 mg, Cr 8
3.1 mg and 30.2 mg of P were attached.

Example 4 Treatment liquid D (fluoric titanic acid was added to an aqueous solution in which chromic acid was reduced to 20% of hexavalent chromium by a methanol reduction method, and the total amount of chromium was 10.4 g / liter, and the amount of Ti was converted to 2.1 g / liter, monoammonium phosphate 24.8 g
/ Liter aqueous solution adjusted to pH 2.2 with sulfuric acid. ) 2 liters were placed in a glass beaker and heated to 75 ° C. To this, 110 g of aluminum atomized powder having an average particle size of 15 μm was added and dispersed. After completely dispersed,
The state was maintained for 60 minutes. Thereafter, the surface-treated composite aluminum particles were collected by filtration, washed with water and methanol, and dried at 110 ° C. for 2 hours. To 100 g of the composite aluminum atomized powder thus obtained, 3 g of stearic acid, 0.5 g of lauryl phosphate and 200 ml of mineral spirit were added and kneaded.
It was crushed and spread for an hour (Hall method). After the completion of the pulverization, the slurry was poured out with mineral spirit and passed through a 325 mesh filter, and then the solid content was separated to obtain a composite aluminum flake cake having a solid content of 94%. The obtained composite aluminum flakes had a thickness of about 0.5 μm and an average diameter of about 36 μm, and Ti, Cr, and P were quantified using XRF (fluorescent X-ray analyzer). , Ti was 7.1 mg, Cr was 31.7 mg, and P was 91.5 mg.

Example 5 Treatment liquid E (contains 1.8 g / liter of titanyl sulfate in terms of Ti equivalent, 6.2 g / liter of diammonium phosphate, 2.2 g / liter of sodium gluconate, pH with acetic acid)
2 liters (adjusted to 3.2) were placed in a glass beaker, and 110 g of aluminum atomized powder having an average particle size of 10 μm was added and dispersed therein. After completely dispersed,
This was heated to 45 ° C. and kept in that state for 250 minutes.
Then, the surface-treated composite aluminum powder was collected by filtration, washed with water and methanol, and dried at 110 ° C. for 2 hours. 100 g of the obtained composite aluminum atomized powder
Then, 4 g of stearyl phosphate, 5 g of lauryl phosphate, and 200 ml of mineral spirit were added and kneaded, and pulverized and spread by a ball mill for 3 hours (Hall method). After the completion of the pulverization, the slurry was poured out with a mineral spirit and passed through a 325 mesh filter, and then the solid was separated to obtain a composite aluminum flake cake having a solid content of 95%. The obtained composite aluminum flakes had a thickness of about 0.3 μm and an average diameter of about 25 μm, and when Ti and P were quantified using XRF (fluorescent X-ray analyzer), 1 g of this composite aluminum flake was Ti. Is 2
4.6 mg and 12.6 mg of P were attached.

Comparative Example 1 Aluminum atomized powder 100 having an average particle size of 15 μm
g, stearic acid 6 g, mineral spirits 200 ml
Was added and kneaded, and pulverized and spread for 3 hours by a ball mill (Hall method). After the completion of the pulverization, the slurry was poured out with mineral spirit and passed through a 325 mesh filter, and then the solid content was separated to obtain an aluminum flake cake having a solid content of 95%. The obtained aluminum flakes had a thickness of about 0.5 μm and an average diameter of about 32 μm.

Comparative Example 2 To 100 g of aluminum flake cake produced in the same manner as in Comparative Example 1, 6 g of diammonium phosphate described in JP-B-34-9729 was added and kneaded.

Comparative Example 3 To 100 g of aluminum flake cake produced in the same manner as in Comparative Example 1, 6 g of lauryl phosphate described in JP-B-60-8057 was added and kneaded.

Comparative Example 4 Aluminum atomized powder 100 having an average particle size of 15 μm
g, stearylamine 6g, mineral spirits 20
0 ml was added and kneaded, and pulverized and spread by a ball mill for 3 hours (Hall method). After crushing, drain the slurry with mineral spirits and pass through a 325 mesh filter.
Solids were separated and aluminum flake cake with 95% solids was dried. The obtained aluminum flakes had a thickness of about 0.5 μm and an average diameter of about 39 μm. Treatment liquid F obtained by heating 100 g of the obtained cake to 80 ° C.
(What is disclosed in Japanese Patent Publication No. 1-54386:
250 ml of chromic anhydride (including 20 g / liter of n-butyl glycol and 100 g / liter) were added and dispersed, and the state was maintained at a liquid temperature of 80 ° C. for 25 minutes. Then, the surface-treated composite aluminum particles were collected by filtration, washed sufficiently with water, and the solid content was separated to obtain a cake having a solid content of 90%.

The aluminum pigments obtained in Examples 1 to 5 and Comparative Examples 1 to 4 were subjected to the following tests. Water resistance test: (1) Preparation of water-based paints 10% by weight of nonionic surfactant and 20% by weight based on the solid content of the aluminum flake cakes obtained in Examples 1-5 and Comparative Examples 1-4. IPA was added and kneaded, and pure water was added to each to adjust the solid content concentration to 60% to obtain nine kinds of aluminum flake pigment dispersions.
For each 15 parts by weight of each of the resulting aluminum flake pigment dispersions, an aqueous acrylic emulsion resin (Aromatex E238 manufactured by Mitsui Toatsu Co., Ltd .:
73 parts by weight of solid content 41%) and 12 parts by weight of pure water are mixed and dispersed using a disperser, and dispersed at 1000 rpm for 10 minutes.
A variety of water-based paints were obtained.

(2) Dispersibility and Storage Stability A hiding rate test paper shown in JIS K 5400 Section 6.3 was prepared, and this test paper was placed on a smooth glass plate,
The coating material (pigment dispersion liquid) described in the above item (1) was bar-coated on a test paper with a # 12 bar coater and dried with a dryer to form a coating film. From the appearance of the obtained coating film, the aggregation state of the pigment and the color tone / gloss were visually evaluated. Further, the paint was left for 15 days, 30 days, or 60 days at room temperature, and the same test and evaluation were performed on each elapsed time.

(3) Hydrogen gas generating property As shown in FIG. 1, the coating material 1 described in the above item (1).
Erlenmeyer flask 2 with a capacity of 200 ml
And placed in a constant temperature water bath 3 at 50 ° C., hydrogen gas generated in 15 days was collected in a graduated cylinder 4, and the total amount was measured. The graduated cylinder 4 used for gas collection
The maximum measured amount of was 20 ml.

The test results are shown in Table 1.

[Table 1]

As is clear from Table 1, all of the aluminum flake pigments obtained in Examples 1 to 5 of the present invention have excellent water resistance (storage stability, luster, hydrogen gas generation resistance). While the results are shown, Comparative Examples 1 to 3 are inferior in stability in long-term storage and hydrogen gas generation resistance, and Comparative Example 4 has hydrogen gas generation resistance, but the pigment is yellowish. The result is that the initial glossiness is lowered. That is, the present invention stably provides practical aluminum flakes having water resistance (storability, luster, hydrogen gas generation resistance), which has not been found in the past.

[0052]

INDUSTRIAL APPLICABILITY The present invention has excellent water resistance (storage stability, glossiness, and hydrogen gas generation resistance) and is extremely useful as a coating pigment, and it can stably provide the composite aluminum flake. The present invention provides a simple manufacturing method.

[Brief description of drawings]

FIG. 1 is an explanatory view of an apparatus for measuring hydrogen gas resistance of the composite aluminum flakes of the present invention.

[Explanation of symbols]

 1 ... Test paint 2 ... Erlenmeyer flask 3 ... Constant temperature water tank 4 ... Measuring cylinder

Claims (5)

[Claims] 1. A substantially granular aluminum particle, and a coating film layer formed on the surface thereof and containing at least one compound containing at least one metal selected from Zr, Ti and Cr. Including, composite aluminum powder. 2. The composite aluminum powder according to claim 1, wherein the coating film layer contains phosphorus. 3. A substantially spherical aluminum particle is contacted with an aqueous treatment liquid containing at least one selected from Zn ion, Ti ion, and Cr ion, whereby the aluminum particle is provided with the above-mentioned on the surface thereof. A method for producing a composite aluminum flake, comprising forming a coating layer containing a metal compound to prepare a composite aluminum powder, and subjecting the composite aluminum powder to a crushing and spreading treatment to form a composite aluminum flake. 4. The aqueous treatment liquid further contains orthophosphate ions, whereby a coating layer containing at least one compound containing the metal and phosphorus is formed on the surface of the aluminum particles. Item 3. The method according to Item 3. 5. The pulverized and spread-out treatment of the composite aluminum powder is at least 1 selected from saturated fatty acids, unsaturated fatty acids, derivatives of these fatty acids, and organic phosphate esters.
The method according to claim 3 or 4, which is carried out in the presence of a grinding aid consisting of seeds.