JP2974518B2 - Surface treatment method for imparting durable luster to flaky pigment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pigment surface treatment method for imparting a durable luster to a pigment, especially a flaky pigment. More specifically, the present invention provides that a surface treatment is carried out with an agent comprising an aqueous solution containing at least one selected from zirconium ions, trivalent chromium and hexavalent chromium ions in a limited ratio, and phosphate ions. The present invention relates to a surface treatment method for imparting durable luster to a flaky pigment with excellent water resistance and weather resistance.

[0002]

2. Description of the Related Art Among the quality requirements for exterior coating films for automobiles and the like, it is particularly important that the appearance quality does not deteriorate even when exposed to various outdoor weather conditions for a long period of time.
It has been known that a chalking phenomenon called chalking occurs in a coating film in which titanium dioxide is dispersed and contained in a resin as a pigment. As means for suppressing such properties of titanium dioxide, at least one selected from chromium compounds, silicon compounds, phosphorus compounds, zirconium compounds, etc. is doped into titanium dioxide for pigments or the surface thereof is coated. Stabilization methods have been proposed.

[0003] Paints in which aluminum flake pigments are dispersed and contained in a resin are used for exterior coating for automobiles, and coatings containing such pigments are also applied when exposed to various weather conditions. It is known that the film appearance deteriorates. An outdoor exposure test is known as a method for evaluating the durability against such weather conditions, but other accelerated evaluation methods such as an accelerated weather resistance test, a wet test, and a high-temperature water immersion test are also known. This makes it possible to evaluate the deterioration of the gloss and color tone of the coating film surface.

Heretofore, metal oxides such as titanium oxide and iron oxide have been used alone or in combination with titanium oxide on the surface of flaky pigment powders such as mica flakes and mica-like iron oxide (hereinafter referred to as mica flakes and the like). Combining iron and coating,
It is known to prepare pigments having pearl luster and to use such luster pigments as colorants for paints, inks, plastics and the like. However, when a paint using a gloss pigment obtained by coating a metal oxide such as titanium dioxide on the surface of such mica flakes is applied to the exterior coating of an automobile or the like, the coating film is
Similar to a coating film made of a coating material in which an aluminum flake pigment is dispersed and contained in a resin, the coating film is not suitable for practical use because the glossiness of the coating film deteriorates in a water resistance test such as a high temperature water immersion test.

[0005] As a cause of deterioration of the gloss and color tone of the coating film surface, water molecules penetrate the coating film and reach the pigment surface to form fine blisters. It is considered that fine pores are formed therein, and the pores remarkably scatter light, thereby deteriorating the gloss and color tone of the coating film surface. As a method for preventing the deterioration of the appearance of a coating film containing a mica flake or the like coated with such a metal oxide as a pigment, a surface treatment method applied to titanium dioxide for a pigment is usually applied. Can be easily analogized. However, pearlescent pigments composed of metal oxide-coated mica flakes and the like have properties much more complicated than mere titanium dioxide for pigments. Even when applied to a pearlescent pigment composed of an object-coated mica flake, the effect of improving water resistance cannot be obtained or is insufficient.

On the other hand, as a method for imparting water resistance to titanium dioxide-coated mica flakes, JP-A-47-34527 discloses a pigment obtained by treating the surface of a pigment base with methacrylate chromium chloride and a method for producing the same. Have been. JP-A-54-96534 discloses a method in which a basic substance such as sodium hydroxide is added to a trivalent chromium compound aqueous solution, and a trivalent chromium hydroxide coating layer is formed using a neutralization precipitation reaction. Is disclosed. JP-A-58-69258 and JP-A-58-69259 disclose a protective layer formed of chromium oxide and / or chromium phosphate, and the resulting pigment is calcined to produce a pearlescent pigment. A method and the pearlescent pigment obtained thereby are disclosed. These methods have been found to be effective to some extent in improving the water resistance of pearlescent pigments composed of titanium dioxide-coated mica flakes, but are still not sufficient.

On the other hand, JP-A-58-174449 discloses that
A basic chromium or aluminum compound,
A method for producing a hydrophobic pearlescent pigment using a carboxylic acid containing more than 4 carbon atoms per carboxyl group in the molecule is disclosed. Also, JP-A-59-7
No. 8265 discloses a pearlescent pigment having methacrylate chromium chloride deposited thereon. These methods use special raw materials such as methacrylate and chromium compounds, which are not only economically disadvantageous, but also
It is difficult to say that the obtained durability improving effect is sufficient. Further, Japanese Patent Application Laid-Open Nos.
No. 2067 discloses a method for producing a pearlescent pigment by hydrolyzing a zirconium compound in the presence of hypophosphite and attaching hydrous zirconium oxide to the surface of a pigment substrate. However, these methods require a very complicated process and strict process control, so that a disadvantage in manufacturing cannot be denied.

Generally, since the surface of a metal material is covered with an oxide, if the metal material is directly coated without being subjected to a surface treatment, a blistered film called blister is generated due to the influence of moisture, temperature and the like. It is known to have the problem that Amorphous alloys are disclosed in, for example,
In the case of a coating film formed from a paint obtained by dispersing and containing flake-form powder in a resin according to the method described in Japanese Patent No. 87209, similar swelling occurs at the interface between the pigment and the resin. As a result, the appearance of the coating film is significantly impaired, and this is a serious obstacle in practical use.

A pearlescent pigment obtained by using flaky powder such as mica flakes as a pigment base material and coating it with a metal oxide is coated with titanium dioxide. A colored mica titanium pigment or flaky flake obtained as a lower titanium oxide by the method described in JP-A-3-79673 or the like is used as a pigment substrate, and electroless plating from an aqueous solution or vapor deposition plating ( (Eg, sputtering, PVD, CVD, etc.) and the like, and a pigment obtained by forming a metal coating, or, for example, JP-A-1-108267 and JP-A-1-10467.
According to the method described in No. 3, even when a pigment obtained by attaching a metal or an alloy to a part of the surface of a pigment substrate made of flaky powder is dispersed and contained in a resin, the resin and the pigment The same phenomenon as described above occurs at the interface, and there is a problem that the long-term appearance quality of the coating film is deteriorated, which hinders the practical use of the pigment.

[0010]

SUMMARY OF THE INVENTION The present invention provides sufficient durability, that is, long-term durability in color tone and gloss, even when exposed to a variety of harsh natural environments outdoors for a long period of time, such as painting the exterior of an automobile body. An object of the present invention is to provide a surface treatment method capable of producing a flaky pigment having luster.

[0011]

The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, the surface of the flaky pigment powder was selected from zirconium ion, trivalent chromium ion and hexavalent chromium ion. By treating with at least one aqueous solution containing phosphate ions to form a film composed of the zirconium, chromium, and phosphorus on the surface of the pigment particles, the pigment particles have excellent moisture resistance, gloss retention, and dispersibility. It has been found that a scaly pigment having a durable luster can be obtained, and the present invention has been completed.

The surface treatment method for imparting a durable luster to a flaky pigment according to the present invention is characterized in that a film composed of zirconium, chromium and phosphorus is coated on the surface of the flaky pigment particles with respect to 1 g of the pigment. 0.5 to 50 in total
It is characterized by being formed in a weight of mg. The method of the present invention comprises, for example, at least one selected from zirconium ion, trivalent chromium ion and hexavalent chromium ion.
The flaky pigment powder is suspended in an aqueous solution containing seeds and phosphate ions, or the flaky pigment powder is previously dispersed and suspended in water, and zirconium ions are dispersed in the dispersion and suspension. It can be carried out by treating the pigment by adding an aqueous solution containing at least one selected from valent chromium ions and hexavalent chromium ions and phosphate ions in advance.

[0013]

Particularly preferred scaly pigments used in the method of the present invention include the following powder materials: (1) mica flakes, (2) aluminum flakes, (3)
An amorphous alloy flake, (4) a mica-like iron oxide (MIO) powder, (5) a core composed of a granular inorganic material having a scale powder, and covering the surface of the core with metal, alloy and metal oxide A powder composed of at least one selected surface layer, (6) a core composed of a flake powder granular inorganic material, and at least one layer covering the surface of the core and laminated in an arbitrary order A metal or alloy coating layer of at least one
Consisting of a powder composed of a metal oxide film layer and a surface layer composed of a metal oxide film layer, (7) a core body composed of flake powder granular inorganic material, and flake powder granular inorganic material particles, and metal oxide formed on the surface thereof At least one kind of core selected from a composite core consisting of an object film layer and an island-like layer formed on the surface of the core in an island shape and made of at least one type selected from metals and alloys And powders consisting of These powder materials have a scale-like shape, and preferably have a thickness of 0.2 to 5 μm and a diameter (major axis and minor axis) of 5 to 500 μm.

The amorphous alloy flake (3) used in the present invention is, for example, 10% Ni, 10% Cr, 2% M
o, 12% P, 8% C, residual Fe amorphous alloy, or 5
% Ni, 15% Cr, 2% Mo, 11% P, 10% C,
It is preferable to be selected from flakes composed of an amorphous alloy of the remaining Fe.

[0015] In the powder materials (5), (6) and (7) used as the substrate in the present invention, the flake powder granular inorganic material used as the core is composed of the powder materials (1), (2) and (2). 3) and (4) can be selected.

Further, in the powder materials (5) to (7), the metal or alloy used for forming the surface layer, the coating layer or the island layer is, for example, gold, silver, copper, palladium, cobalt, aluminum, Nickel-phosphorus alloy, nickel-boron alloy, nickel-cobalt-phosphorus alloy,
It can be selected from nickel-tungsten-phosphorus alloy, gold-silver alloy, cobalt-phosphorus alloy and the like.

Further, in the powder materials (5), (6) and (7), the metal oxide used for forming the surface layer or the coating layer is, for example, titanium dioxide, iron oxide, aluminum hydroxide, You can choose from silicon dioxide, zirconium dioxide, and tin dioxide.

In the powder materials (5) to (7), the weight ratio between the core and the surface layer is preferably 99/1 to 30/70. In the powder material (6), a titanium dioxide film layer is preferably formed on the core, and the outermost surface of the surface layer is preferably formed by a silver film layer. The weight ratio between the layer and the metal oxide film layer is preferably 5/95 to 50/50.

In the above powder material (7), the weight ratio of the scale-like granular inorganic material particles in the composite core to the metal oxide film layer is preferably from 95/5 to 40/60, and The layer has a surface of the core or the composite core of 0.05 to
It is preferable that 95% of the island-like layers are covered, and the island-like layers each have an average particle diameter of 0.01 to 5 μm and are composed of island-like bodies separated from each other.

In the surface treatment method of the present invention, a treatment agent containing necessary components (at least one selected from zirconium ion, trivalent chromium ion and hexavalent chromium ion, and phosphate ion) is prepared as a concentrated aqueous solution. It is also possible to carry out surface treatment by bringing the aqueous solution of the treating agent into contact with a dispersion in which the scaly pigment to be treated is dispersed in water at a fixed ratio (hereinafter referred to as Method A). Alternatively, the flaky pigment is dispersed at a predetermined ratio in an aqueous solution in which a treating agent containing at least one selected from zirconium ion, trivalent chromium ion and hexavalent chromium ion and phosphate ion is dissolved at a predetermined concentration, and the surface is dispersed. It is also possible to perform a process (hereinafter, this is referred to as a B method). Here, there is no particular limitation on the temperature of the processing solution at the time of performing the processing, but it is generally preferable that the temperature be 20 ° C to 90 ° C.

In any of the above methods A and B, the weight of the coating containing zirconium, chromium and phosphorus in the method of the present invention is based on the total amount of the above elements per 1 g of the flake pigment to be treated. 0.5 to 50 mg. In particular, this film is composed of 1 g of scaly pigment which is an object
It is preferable to contain 0.05 to 15 mg of zirconium, 0.1 to 25 mg of chromium, and 0.03 to 10 mg of phosphorus per element conversion.

If the coating amount of zirconium is less than 0.05 mg per 1 g of the flake pigment to be treated, the amount of the surface treatment film on the flake pigment may be insufficient, and the required effect of improving the durability may not be obtained. The zirconium coating amount is 15
Above mg, the above effects reach saturation and are uneconomical.

If the coating amount of chromium is less than 0.1 mg per 1 g of the flake pigment which is an object to be treated, the amount of the surface treatment coating on the flake pigment may be insufficient, and the necessary effect of improving the durability may not be obtained. is there. On the other hand, if the amount of chromium film exceeds 25 mg, the above effects reach saturation, which is uneconomical.

Further, if the coating amount of phosphorus per 1 g of the flake pigment to be treated is less than 0.03 mg, the amount of the surface treatment coating on the flake pigment may be insufficient, and the necessary effect of improving the durability may not be obtained. is there. On the other hand, if the amount of the phosphorus film exceeds 10 mg, the above effect reaches saturation, which is uneconomical.

In each of the methods A and B as described above, the concentration of each component is not particularly limited. However, the ion content of each component in the preferable aqueous solution of the treating agent in the method A is preferably zirconium ion Is 20mg-50g /
It is preferable that at least one selected from the group consisting of liter, trivalent chromium and hexavalent chromium ions is 20 mg to 50 g / liter, and phosphate ion is 1.2 mg to 120 g / liter.

In method A, if the zirconium ion concentration is less than 20 mg / l, a sufficient zirconium coating amount may not be obtained, and if it exceeds 50 g / l, the effect reaches saturation and it is not economical. If the concentration of at least one selected from trivalent chromium ions and hexavalent chromium ions is less than 20 mg / liter, a sufficient amount of chromium film may not be obtained, and if it exceeds 50 g / liter, the effect reaches saturation. Not economic. If the concentration of phosphate ions is less than 1.2 mg / liter, a sufficient amount of the phosphorus film may not be obtained, and if it exceeds 120 g / liter, the effect reaches saturation and is not economical.

The same phenomenon as described above also occurs in the method B in the present invention. That is, the preferable content of at least one selected from zirconium ion, trivalent chromium ion and hexavalent chromium ion and phosphate ion in the aqueous solution in method B is 0.5 mg or less of zirconium ion.
10 g / liter, at least one selected from trivalent chromium ions and hexavalent chromium ions is 0.5 mg to 10
g / liter and phosphate ion of 0.3 mg to 40 g /
Liters. 0.5mg zirconium ion concentration
If the amount is less than 1 g / liter, a sufficient amount of zirconium film may not be obtained. If the amount exceeds 100 g / l, the effect reaches saturation and it is not economical. If the concentration of at least one selected from trivalent chromium ions and hexavalent chromium ions is less than 0.5 mg / l, a sufficient amount of chromium film may not be obtained, and if it exceeds 10 g / l, the effect is saturated. Reached, not economical. If the concentration of phosphate ions is less than 0.3 mg / liter, a sufficient amount of the phosphorus film may not be obtained, and if it exceeds 40 g / liter, the effect reaches saturation and is not economical.

The dispersion concentration of the flaky pigment used in the surface treatment in the method B in water is not particularly limited, but is preferably from 10 to 500 g per liter of the aqueous solution. When the weight of the flaky pigment per liter of the aqueous solution is less than 10 g, the ratio to the aqueous solution to be used is small, and the treatment efficiency is low, which is uneconomical. Aqueous solution 1
If the weight of the flaky pigment per liter exceeds 500 g, the ratio to the aqueous solution to be used becomes high, and the stirrer required for maintaining a suitable dispersed state becomes large, which is disadvantageous in equipment.

The source of each component to be used is not particularly limited. Examples of the source of zirconium ion include zirconium fluoride, ammonium salts of zirconium fluoride and alkali metals of zirconium fluoride. One or more selected from salts can be used. Examples of the source of trivalent chromium ion and hexavalent chromium ion include a water-soluble organic acid salt, an inorganic acid salt of trivalent chromium, a partially reduced product of an aqueous solution of chromic anhydride, and dichromic acid, and an ammonium salt of dichromic acid. And one or more selected from alkali metal salts. As a supply source of phosphate ions, various supply forms are possible, but from the viewpoint of economy, ease of acquisition, etc.,
One or more kinds selected from phosphoric acid, ammonium salts of phosphoric acid, and alkali metal salts of phosphoric acid can be used.

In each of Method A and Method B, the scaly pigment-treated solution prepared as described above was stirred and heated to a temperature of 20 ° C. to 90 ° C. while maintaining the dispersion state.
A film is formed on the surface of the pigment particles, and the obtained surface-treated pigment is collected (filtered), washed with water, and then dried. This makes it possible to obtain a flaky pigment having a durable gloss excellent in moisture resistance, gloss retention and dispersibility. The processing temperature and the processing time of the processing solution required for processing the flaky inorganic pigment powder should be determined by industrial profitability, whereby the required processing temperature and the processing time can be appropriately determined. .

Although the form of the zirconium, chromium, and phosphorus films deposited on the surface of the pigment particles by the above treatment according to the present invention is not clear, according to XPS (X-ray photoelectron spectroscopy), hexavalent zirconium. It is presumed to be in the form of an oxide or a complex of hydroxide and phosphate.

In the present invention, the presence or absence and the temperature of the flaky pigment obtained by the above treatment after filtration and washing with water are not particularly specified. It is not preferable because the color tone of the obtained flaky pigment may be changed.

The scaly pigment having a durable luster obtained in this manner is suitable for use by being mixed with a coating composed of a thermosetting resin or a lacquer type resin by a known method. The coating layer obtained by applying the flaky pigment-containing resin subjected to such a surface treatment to metal, plastic, wood, concrete, glass, or the like, exhibits satisfactory durable gloss under outdoor conditions. In particular, it retains a sufficiently satisfactory water resistance as a coloring agent for exterior paints for automobiles. In addition, the surface-treated pigment obtained by the method of the present invention has excellent dispersibility, and can be used as a paint exhibiting excellent design properties without impairing the color tone and gloss originally possessed by the pigment.

[0034]

EXAMPLES The effects of the present invention will be described more specifically with reference to examples, but the present invention is not particularly limited to these experimental conditions.

Example 1 Fluorinated zirconate was converted to zirconium ion in an amount of 0.1%.
And 0.03 g / liter of trivalent chromium ions (produced by a tannic acid reduction method and using an aqueous solution of chromium chromate containing about 20% of trivalent chromium ions based on the total chromium ions). And 1 liter of an aqueous solution containing 0.03 g / liter of phosphoric acid. A mica flake was used as a substrate, and aluminum was adhered to a part of the substrate by a sputtering method.
10 g of a 0 μm metal-coated mica flake was dispersed in the above aqueous solution with stirring, heated to 60 ° C. while stirring, and kept at this temperature for about 30 minutes. The dispersion is then filtered and the solid product is collected by filtration, washed with water,
Dry at 5 ° C. for 5 hours. The film formed on the pigment was as follows: Zr: 1.85 mg, Cr: 1.80 mg, P:
It consisted of 0.64 mg.

Example 2 500 g of amorphous alloy flakes were dispersed in 990 ml of water. This alloy flake has Ni (10 atomic%), Cr (10 atomic%), Mo (2 atomic%), P
(12 at%), C (8 at%), residual Fe and unavoidable impurities, and had a powder form. The thickness of this powder is 1 to 4 μm, the aspect ratio (the ratio of the major axis to the thickness) is 10 to 100, the ratio of the minor axis to the major axis is 1 to 5,
The minor axis and major axis dimensions were 10 to 400 μm. Separately, an aqueous solution containing 2.5 g / l of zirconium fluoride in terms of zirconium ion, 25 g / l of chromium nitrate in terms of trivalent chromium ion, and 175 g / l of phosphoric acid was prepared. Add to the powder dispersion and heat to 90 ° C.
Hold for 0 minutes. The dispersion was then filtered, the solid product was collected by filtration, washed with water and dried at 160 ° C. for 3 hours. Pigment 1
The film formed on the pigment per g was Zr: 0.033 m
g, Cr: 0.33 mg, P: 0.56 mg.

Example 3 200 g of metal oxide-coated mica flakes were dispersed in 900 ml of water. This mica flake is coated with titanium dioxide at about 20% of the weight of the mica flake and has a particle size of 10 to 50 μm.
Met. 0.8 g / l of zirconium ion in terms of zirconium ion and 1.5 parts of trivalent chromium ion
% Of an aqueous chromium chromate solution containing 2% by weight of trivalent chromium ion and 1.5 g / liter of phosphoric acid, and 100 ml of the aqueous solution is added to the above metal-coated mica flake dispersion while stirring. The mixture was heated to 70 ° C. and kept for about 30 minutes. Next, this dispersion was filtered, and the solid product was collected by filtration, washed with water, and dried at 140 ° C. for 3 hours. The film formed on the obtained pigment was Z / g of pigment.
r: 0.25 mg, Cr: 33 mg, P: 0.16 mg.

Example 4 Ammonium fluoride zirconate was 0.9 g / l in terms of zirconium ion, chromium nitrate was 0.2 g / l in terms of trivalent chromium ion, and phosphoric acid was 0.1 g / l.
1000 ml of an aqueous solution containing 4 g / l was prepared.
Separately, titanium dioxide is coated on a substrate composed of mica flakes at about 46% by weight, and a metal oxide / metal bilayer coating obtained by coating a part of the substrate with aluminum by sputtering. Mica flake (grain size 5-20 μm) 1
00g was dispersed in the above aqueous solution, which was heated to 90 ° C. with stirring and maintained for about 10 minutes. Next, the dispersion was filtered, and the solid product was collected by filtration, washed with water, and dried at 140 ° C. for 2 hours. The film formed on the pigment is
Zr: 7.2 mg, Cr: 1.3 mg, P: 0.96 mg.

Example 5 100 g of metal oxide-coated mica flakes obtained by coating mica flakes on a substrate and coated with about 60% by weight of iron oxide and having a particle size of 5 to 20 μm were dispersed in 500 ml of water. Separately, ammonium fluoride zirconate is 180 mg / l in terms of zirconium ion, chromium fluoride is 54 mg / l in terms of trivalent chromium ion, and phosphoric acid is 4 mg / l.
Prepare an aqueous solution containing 8 mg / l, and add 500 ml
Was added to the above metal-coated mica flake dispersion, and the mixture was heated to 90 ° C. and kept for about 10 minutes while stirring. The dispersion is then filtered, the solid product is filtered, washed with water and
Dried for hours. The film formed on the pigment was 0.47 mg of Zr, 0.081 mg of Cr, and 0.1% of P per 1 g of the pigment.
It consisted of 065 mg.

Example 6 A scaly powder (particle size) obtained by coating titanium dioxide on a substrate composed of mica flakes in an amount of about 46% based on the weight thereof and further depositing silver in an island shape by electroless plating. 5 to 20 μm)
200 g were dispersed in 600 ml of water. Separately, 400 ml of an aqueous solution containing 0.9 g / l of fluorinated zirconate in terms of zirconium ion, 72 mg / l of chromium sulfate in terms of trivalent chromium ion, and 0.56 g / l of phosphoric acid was added to the above amorphous alloy. The mixture was added to the powder dispersion, heated to 60 ° C. while stirring, and maintained for about 30 minutes.
Next, this dispersion was filtered, the solid product was collected by filtration, washed with water, and dried at 120 ° C. for 3 hours. The film formed on the pigment was composed of 0.93 mg of Zr and 0.0 of Cr per 1 g of the pigment.
72 mg, P: 0.56 mg.

EXAMPLE 7 Using mica flakes as a substrate, titanium dioxide / lower titanium oxide-coated mica flakes coated with about 40% by weight of titanium dioxide and about 9% of lower titanium oxide (particle size: 10 to 50 μm)
m) 200 g were dispersed in 9000 ml of water. Separately, 100 ml of an aqueous solution containing 16 g / l of ammonium fluoride zirconate in terms of zirconium ion, 3.6 g / l of chromium sulfate in terms of trivalent chromium ion, and 28 g / l of phosphoric acid are mixed with the above metal-coated mica flake dispersion. And heated to 75 ° C while stirring continuously for about 2
Hold for 0 minutes. Next, the dispersion was filtered, and the solid product was collected by filtration, washed with water, and dried at 110 ° C. for 4 hours. The film formed on the pigment had a Zr of 5.2 mg / g of pigment / g of pigment.
r: 1.2 mg, P: 2.9 mg.

Example 8 The surface of mica flakes was obtained by coating the surface with about 45% by weight of titanium dioxide and further coating the surface with about 10% of titanium metal by sputtering.
100 g of a metal oxide / metal bilayer coated mica flake having a particle size of 10 to 20 μm was dispersed in 900 ml of water. Separately, 0.4 g of zirconium ion in terms of zirconium fluoride
Per liter of chromic anhydride in terms of hexavalent chromium ion
g / L and an aqueous solution containing 0.75 g / L of phosphoric acid was prepared, and 100 mL of the aqueous solution was added to the above-mentioned metal oxide / metal bilayer-coated mica flake dispersion.
C. and kept at this temperature for about 30 minutes. The dispersion was then filtered, the solid product was collected by filtration, washed with water and dried at 120 ° C. for 3 hours. The film formed on the pigment per 1 g of the pigment was Zr: 0.26 mg, Cr: 0.65 mg,
P: It consisted of 0.15 mg.

COMPARATIVE EXAMPLE 1 100 g of a metal oxide-coated mica flake obtained by coating a substrate comprising mica flakes with about 20% by weight of titanium dioxide and having a particle size of 10 to 50 μm was slurried with 1700 ml of distilled water. The pH was adjusted to 6.0 by dropwise addition of 2N sulfuric acid.
Was adjusted. Separately, 5% chromic chloride (CrCl ₃ )
32 ml of the aqueous solution was diluted with 100 ml of distilled water and this solution was added at a constant rate to the slurry over a period of about 30 minutes. During the step of adding the aqueous solution of chromic chloride, the pH was maintained at 6.0 by adding a 10% sodium hydroxide solution. After the entire amount of the chromic chloride solution was added to the slurry, the resulting slurry was filtered, and the obtained surface-treated pigment was washed with water and dried at 110 to 120 ° C for 1 hour. The film formed on the pigment had a Zr of 0 mg and a Cr of 0.04 per gram of the pigment.
mg, P: 0 mg.

COMPARATIVE EXAMPLE 2 100 g of a metal oxide-coated mica flake obtained by coating a substrate composed of mica flakes with about 60% by weight of iron oxide and having a particle size of 5 to 20 μm was slurried with 1700 ml of distilled water. The pH was adjusted to 6.0 by dropwise addition of 2N sulfuric acid. Separately, a 5% chromic chloride (CrCl ₃ ) solution 32
ml was diluted with 100 ml of distilled water and this solution was added at a constant rate to the slurry over a period of about 30 minutes. During the addition of chromic chloride, the pH was maintained at 6.0 by adding 10% sodium hydroxide solution. After the entire amount of the chromic chloride solution was added, the slurry was filtered, and the obtained surface-treated pigment was washed with water and dried at 110 to 120 ° C for 1 hour. The film formed on the pigment was Zr: 0 per gram of the pigment.
mg, Cr: 0.04 mg, P: 0 mg.

Comparative Example 3 100 g of flaky powder obtained by depositing silver in the form of islands on the same titanium dioxide-coated mica flakes as the pigment used in Example 6 by electroless plating was used. The same processing was performed. The film formed on the pigment has a Z
r: 0 mg, Cr: 0.04 mg, P: 0 mg.

Comparative Example 4 The same treatment as in Comparative Example 2 was carried out using 100 g of a mica flake coated with the same metal oxide and metal as the pigment used in Example 7. The film formed on the pigment has a Z
r: 0 mg, Cr: 0.04 mg, P: 0 mg.

Comparative Example 5 A titanium dioxide / lower titanium oxide-coated mica flake having the same particle size of 10 to 50 μm as the pigment used in Example 3 was washed with water and
Dried at 20 ° C. for 3 hours. No film was formed.

[Test Method] High-Temperature Water Resistance Test: (1) Preparation of Paint (A) Thermosetting Acrylic Melamine Resin Base Paint 13 types of surfaces obtained in Examples 1 to 8 and Comparative Examples 1 to 5 Each of the coated pigments is made of a thermosetting acrylic melamine resin (manufactured by Dainippon Ink and trademark: Acrydik A-32
15 parts by weight were added to 85 parts by weight of a solid content of 2,160 parts by weight and a solid content of Dainippon Ink and trade name: Super Beckamine L117-60, 34 parts by weight) to prepare 13 kinds of paints.

(B) Thermosetting acrylic melamine resin-based clear paint Trade name: Acridic A-310 (14) manufactured by Dainippon Ink.
(0 parts by weight) and Dainippon Ink Ink's trademark: Super Beckamine L117-60 (50 parts by weight) were mixed to prepare a thermosetting acrylic melamine resin clear paint.

(C) Two-component curable acrylic urethane resin-based base paint The 13 types of surface-coated pigments obtained in Examples 1 to 8 and Comparative Examples 1 to 5 were coated with a two-component curable acrylic urethane resin (Dainippon Ink Made, trademark: Acrydik 54-480,10
0 parts by weight, manufactured by Mitsui Toatsu, trademark: Olestar NP-10
15 parts by weight were added to 85 parts by weight of the solid content of the mixture (00, 20 parts by weight) to prepare 13 kinds of paints.

(D) Two-component curable acrylic urethane resin-based clear coating: Acrylic 54-480 (1)
00 parts by weight) and a trademark made by Mitsui Toatsu: Orester NP-
1000 (20 parts by weight) to prepare a two-part curable acrylic urethane resin clear coating.

(2) Preparation of Performance Test Plate After cold-rolled steel plate (size = 70 × 150 mm) was subjected to automotive pre-treatment, cation electrodeposition and intermediate coating were sequentially performed to obtain 52 intermediate coated plates. Produced. Next is 26 of them
Further, 13 kinds of acrylic melamine resin-based base paints (A) formed as described above were applied to each of the plates so as to have a dry film thickness of 15 μm, and then wet-on-wet.
Acrylic melamine resin clear paint (B) by t method
Is applied to a dry film thickness of 35 μm.
The mixture was heated and cured for 0 minute to prepare 13 types of test plates, two each. Similarly, 13 types of acrylic urethane resin-based base paints (C) were applied so that each had a dry film thickness of 15 μm, and then an acrylic urethane resin-based clear paint (D) was dried by a wet-on-wet method to a dry film thickness of 35 μm.
And then heat and cure at 80 ° C for 30 minutes.
Two test plates were prepared for each of the three types.

(3) Performance test conditions [High-temperature water resistance test] Half of the 26 kinds of test plates (12 types of coating A / B, 12 types of coating C / D) prepared as described above were subjected to half of the longitudinal direction at 80 ° C. After immersion in warm water for 24 hours, the change in the painted surface between the immersed portion and the unimmersed portion was visually determined.

[Accelerated weathering test] Test plate 2 similar to the above
The four types were subjected to an accelerated weather resistance test with a sunshine weatherometer for 1000 hours, and the gloss retention before and after the test (Δ
G) and color difference (ΔE) were measured.

Table 1 shows the results of the high-temperature water resistance test and the accelerated weather resistance test.

[0056]

[Table 1]

As is clear from Table 1, the flaky pigments having luster obtained in Examples 1 to 8 of the present invention showed remarkably good results in the high-temperature water resistance test and the accelerated weather resistance test. . On the other hand, the pigments of Comparative Examples 1 to 5 are significantly inferior to the Examples in the high-temperature water resistance test and the accelerated weather resistance test and cannot be used under severe conditions such as the outer surface coating of automobile bodies. Met. further,
Even in the production process, Comparative Examples 1 to 5 require complicated chemical liquid management, whereas Examples 1 to 8 according to the present invention have the advantage that a good product can be obtained by a simple method. It is.

[0058]

The flaky pigment surface-treated by the method of the present invention has extremely high temperature water resistance and durable luster having weather resistance, and is suitable for use as an external paint for automobile bodies and other uses. It is useful. Further, according to the method of the present invention, a surface treatment for imparting a durable gloss to the flaky pigment can be efficiently carried out.

Continuation of the front page (51) Int.Cl. ⁶ Identification code FI C09C 1/62 C09C 1/62 (72) Inventor Mikio Asai 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Ito Hiroshi 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (58) Field surveyed (Int. Cl. ⁶ , DB name) C09C 3/06 B22F 1/02 C08K 9/02 C09B 67/08

Claims (6)

(57) [Claims] 1 g of this pigment is applied to the surface of the flaky pigment particles.
A surface treatment method for imparting durable luster to a flaky pigment, characterized in that a coating containing zirconium, chromium, and phosphorus is formed in a weight of 0.5 to 50 mg in terms of the total amount of the above elements. 2. For the formation of the surface film, the flaky pigment is dispersed in water at a rate of 10 to 500 g per liter of water, and zirconium ions are added to the aqueous dispersion of the pigment in an amount of 20 mg to 50 g / l. Liter, at least one selected from trivalent chromium ions and hexavalent chromium ions
mg to 50 g / liter, and 1.2 mg of phosphate ion
An aqueous solution of the treating agent containing 1 to 250 g per liter of an aqueous dispersion of the pigment is added at a ratio of 1 to 250 ml per liter of an aqueous dispersion of the pigment to bring the scaly pigment into contact with the treating agent, and the resulting surface-treated pigment is captured. 2. Collecting, washing and drying.
Surface treatment method according to 1. 3. The method for forming the surface film, wherein zirconium ion is 0.5 mg to 10 g / l, at least one selected from trivalent chromium ion and hexavalent chromium ion is 0.5 mg to 10 g / l. 10 to 500 g of the flaky pigment is added per liter to an aqueous solution of the treating agent containing 0.3 mg to 40 g / liter of phosphate ions.
The surface treatment method according to claim 1, wherein the surface-treated scale pigment is dispersed from the aqueous solution, washed with water, and dried. 4. The scaly pigment is (1) mica flake, (2) aluminum flake, (3) amorphous alloy flake, (4) mica-like iron oxide (MIO) powder, (5) flake powder granular Powder consisting of a core made of an inorganic material and a surface layer covering the surface of the core and made of at least one selected from metals, alloys and metal oxides; And a surface layer comprising at least one metal or alloy coating layer and at least one metal oxide coating layer, which cover the surface of the core body and are laminated in an arbitrary order. And (7) a core composed of flake powder granular inorganic material, and a composite core composed of flake powder granular inorganic material particles and a metal oxide film layer formed on the surface thereof At least one type of core The powder according to any one of claims 1 to 3, wherein the powder is formed on the surface of the core in the form of islands and is composed of at least one kind of island-like layer selected from metals and alloys. The surface treatment method according to claim 1. 5. The zirconium ion is supplied from at least one selected from zirconium fluoride, an ammonium salt or an alkali metal salt of zirconium fluoride, and is selected from the trivalent chromium ion and the hexavalent chromium ion. At least one of a water-soluble organic acid salt, an inorganic acid salt of trivalent chromium, and a partially reduced product of an aqueous solution of chromic anhydride, and dichromic acid, an ammonium salt of dichromic acid;
The phosphate ion is supplied from at least one selected from alkali metal salts, and the phosphate ion is supplied from at least one selected from phosphoric acid, an ammonium salt of phosphoric acid, and an alkali metal salt of phosphoric acid. 5. The surface treatment method according to any one of items 1 to 4. 6. A coating containing zirconium, chromium and phosphorus, wherein 0.05 to 15 mg of zirconium and 0.1 to 0.1% of chromium are converted into element weight per 1 g of pigment.
The surface treatment method according to claim 1, wherein the surface treatment composition contains ２５25 mg and 0.03３10 mg of phosphorus.