JPH06116509A - Surface treatment method for imparting durable luster to scaly pigment - Google Patents

Abstract

(57) [Abstract] [Purpose] A surface treatment for producing a scaly pigment having a gloss that is durable enough to be exposed to a harsh environment for a long time, such as an exterior coating of an automobile body. Provide a way. [Structure] A coating film containing zirconium, chromium, and phosphorus is formed on the surface of the scaly pigment particles in an amount of 0.5 to 50 mg in terms of the total amount of the elements per 1 g of the pigment.

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 durable luster to pigments, particularly flake pigments. More specifically, in the present invention, the surface treatment is performed with an agent comprising an aqueous solution containing zirconium ions, at least one selected from trivalent chromium and hexavalent chromium ions in a limited ratio, and a phosphate ion. The present invention relates to a surface treatment method for imparting durable luster to a flaky pigment, which is excellent in water resistance and weather resistance.

[0002]

2. Description of the Related Art Of the qualities required for coating films for automobiles and the like, what is particularly important is that the appearance quality does not deteriorate even when exposed to various outdoor weather conditions.
It has been conventionally known that in the case of a coating film in which titanium dioxide is dispersed and contained as a pigment in a resin, a chalking phenomenon called choking occurs. 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. The method of stabilizing by doing so is proposed.

A paint containing aluminum flake pigment dispersed and contained in a resin is used for the exterior coating of automobiles. A coating film containing such a pigment is 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 durability against such weather conditions, and other tests such as an accelerated weather resistance test, a wet test, and a high temperature water immersion test are known as accelerated evaluation methods. Therefore, it is possible to evaluate the deterioration of gloss and color tone of the coating film surface.

Conventionally, metal oxides such as titanium oxide and iron oxide are used alone or on the surface of scale-like pigment powders such as mica flakes and mica-like iron oxides (hereinafter referred to as mica flakes), respectively. Coated with iron,
It is known to prepare pearlescent pigments and to use such lustrous pigments as colorants for paints, inks, plastics and the like. However, when a paint using a luster pigment obtained by coating a metal oxide such as titanium dioxide on the surface of such mica flakes is applied to the outer surface coating of automobiles, etc., the coating film is
Similar to a coating film made of a paint in which an aluminum flake pigment is dispersed and contained in a resin, it deteriorates the gloss of the coating film in a water resistance test such as a high temperature water immersion test and is not suitable for practical use.

As a cause of deterioration of gloss and color tone of the coating film, water molecules permeate the coating film and reach the pigment surface to form fine swelling, and then water evaporates to form a coating film. It is considered that minute pores are formed in the pores and the pores remarkably scatter light to deteriorate the gloss and color tone of the coating film surface. In a coating film containing such mica flakes coated with a metal oxide as a pigment, as a method for preventing the deterioration of its appearance, apply the surface treatment method applied to ordinary titanium dioxide for pigments. Can be easily analogized. However, pearlescent pigments composed of mica flakes coated with metal oxides have much more complicated properties than mere pigmentary titanium dioxide. Therefore, the same method as the surface treatment of pigmentary titanium dioxide is used for metal oxidation. Even if it is applied to a pearl luster pigment composed of a substance-coated mica flakes, its water resistance improving effect is not obtained, or even if it exists, it 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 this pigment substrate with methacrylate chromium chloride and a method for producing the pigment. Has been done. Further, JP-A-54-96534 discloses a method of forming a trivalent chromium hydroxide coating layer by adding a basic substance such as sodium hydroxide to an aqueous solution of a trivalent chromium compound and utilizing a neutralization precipitation reaction. Is disclosed. Further, in JP-A-58-69258 and JP-A-58-69259, a protective layer is formed of chromium oxide and / or chromium phosphate, and the obtained pigment is baked to produce a pearlescent pigment. A method and the pearlescent pigments obtained thereby are disclosed. These methods show some effects in improving the water resistance of pearlescent pigments composed of titanium dioxide-coated mica flakes, but are still not sufficient.

On the other hand, Japanese Patent Application Laid-Open No. 58-174449 discloses that
With a basic chromium compound or aluminum compound,
A process for making hydrophobic pearlescent pigments using carboxylic acids containing more than 4 carbon atoms per carboxyl group in the molecule is disclosed. In addition, JP-A-59-7
No. 8265 discloses pearlescent pigments having a methacrylic chromium chloride deposited. These methods use special raw materials such as methacrylate / chromium compounds, which is not only economically disadvantageous, but also
It is hard to say that the durability improvement effect obtained is sufficient. Further, JP-A-63-130673 and JP-A-1-29
No. 2067 discloses a method for producing a pearlescent pigment by hydrolyzing a zirconium compound in the presence of a hypophosphite and depositing hydrous zirconium oxide on the surface of a pigment substrate. However, these methods require a very complicated process and strict process control, and therefore the manufacturing disadvantage cannot be denied.

In general, the surface of a metal material is covered with an oxide. Therefore, when the metal material is directly coated without being surface-treated, a blister called a blister occurs due to the influence of moisture, temperature and the like. Is known to have the problem. Amorphous alloys have been used, for example
Also in the case of a coating film formed from a paint in which flaky powder obtained by the method described in No. 87209 is used as a pigment and dispersed and contained in a resin, similar swelling occurs at the interface between the pigment and the resin. This is a serious obstacle to practical use because it occurs and the appearance of the coating film is significantly impaired.

Further, scaly powder such as mica flakes is used as a pigment base material, and a pearlescent pigment obtained by coating it with a metal oxide, mica flakes are coated with titanium dioxide, and the titanium dioxide coating layer is further applied. , A colored mica titanium pigment obtained as a low order titanium oxide by the method described in JP-A-3-79673, etc., or a flaky flakes is used as a pigment substrate, and an electroless plating method from an aqueous solution or a vapor deposition plating method ( Pigments obtained by forming a metal coating by applying (including sputtering, PVD, CVD, etc.), or, for example, JP-A-1-108267 and JP-A-1-10467.
According to the method described in No. 3, when a pigment obtained by adhering a metal or an alloy to a part of the surface of a pigment base made of flaky powder is dispersedly contained in a resin, The phenomenon similar to the above occurs at the interface, and there is a problem that the long-term appearance quality of the coating film deteriorates, which hinders the practical use of the pigment.

[0010]

DISCLOSURE OF THE INVENTION The present invention provides sufficient durability, that is, long-term durability in terms of color tone and gloss even when exposed to various severe outdoor natural environments such as coating on the outer surface of an automobile body. The present invention is intended to provide a surface treatment method capable of producing a lustrous scaly pigment having the same.

[0011]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have selected the surface of the flaky pigment powder from zirconium ion, trivalent chromium ion and hexavalent chromium ion. By treating with an aqueous solution containing at least one kind and a phosphate ion to form a film composed of zirconium, chromium and phosphorus on the surface of the pigment particles, excellent moisture resistance, gloss retention and dispersibility are achieved. It was 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 the scaly pigment according to the present invention comprises a coating of zirconium, chromium and phosphorus on the surface of the scaly pigment particles, per 1 g of the pigment, of the above elements. 0.5-50 converted to the total amount
It is characterized by being formed with a weight of mg. The method of the present invention comprises at least one selected from, for example, zirconium ion, trivalent chromium ion and hexavalent chromium ion.
The flaky pigment powder is suspended in an aqueous solution containing a seed and a phosphate ion, or the flaky pigment powder is previously dispersed / suspended in water, and zirconium ion, 3 It can be carried out by adding an aqueous solution containing at least one selected from valent chromium ions and hexavalent chromium ions and a phosphate ion in advance to treat the pigment.

[0013]

The following powder materials are particularly preferable for use in the method of the present invention: (1) Mica flakes, (2) Aluminum flakes, (3)
A core made of amorphous alloy flakes, (4) micaceous iron oxide (MIO) powder, and (5) scale powder granular inorganic material, and a surface of the core, and a metal, alloy or metal oxide. At least one layer comprising a powder comprising a surface layer comprising at least one selected from the above, (6) a core body comprising a scale powder granular inorganic material, and the surface of the core body and being laminated in any order. A metal or alloy coating layer, and at least one
Layer consisting of a surface layer composed of a metal oxide film layer of a layer, (7) a core body consisting of scale powder granular inorganic material, and scale powder granular inorganic material particles, and metal oxide formed on the surface thereof At least one kind of core body selected from a composite core body comprising a material film layer, and an island-like layer formed on the surface of the core body in an island shape and comprising at least one kind selected from metals and alloys And a powder consisting of, and the like. It is preferable that these powder materials have a scaly shape and 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 flakes (3) used in the present invention are, 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 preferably selected from flakes made of an amorphous alloy of residual Fe.

Further, in the powder materials (5), (6) and (7) used as the substrate in the present invention, the scale-like granular inorganic material used as the core body is the powder materials (1), (2) and ( It can be selected from 3) and (4).

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

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

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

In the surface treatment method of the present invention, a treatment agent containing necessary components (zirconium ion, at least one selected from trivalent chromium ion and hexavalent chromium ion, and phosphate ion) in advance as a concentrated aqueous solution. Alternatively, it is also possible to contact the aqueous solution of the treatment agent with a dispersion liquid in which a scaly pigment to be treated is dispersed in water at a constant ratio to perform surface treatment (hereinafter, referred to as method A). Alternatively, the scaly pigment is dispersed at a constant ratio in an aqueous solution in which a treatment agent containing at least one selected from zirconium ions, trivalent chromium ions and hexavalent chromium ions and a phosphate ion is dissolved in a target concentration, and the surface is dispersed. It is also possible to perform processing (hereinafter, this is referred to as method B). There is no particular limitation on the temperature of the treatment liquid when performing the treatment here, but it is generally preferable to set the temperature to 20 ° C to 90 ° C.

In any of the above methods A and B, the weight of the film containing zirconium, chromium and phosphorus in the method of the present invention is the total amount of the above elements per 1 g of the scale-like pigment which is the object to be treated. And 0.5 to 50 mg. In particular, this film is 1 g of scale-like pigment which is the object to be treated.
Therefore, 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 in terms of elements.

If the coating amount of zirconium is less than 0.05 mg per 1 g of the flaky pigment to be treated, the amount of the surface-treated coating on the flaky pigment may be insufficient and the required effect of improving durability may not be obtained. The zirconium film amount is 15
When the amount exceeds mg, the above effect reaches saturation, which is uneconomical.

If the coating amount of chromium is less than 0.1 mg per 1 g of the flaky pigment to be treated, the amount of the surface-treated coating on the flaky pigment will be insufficient and the required effect of improving durability will not be obtained. is there. On the other hand, if the amount of chromium coating exceeds 25 mg, the above effect reaches saturation, which is uneconomical.

Further, if the coating amount of phosphorus is less than 0.03 mg per 1 g of the scaly pigment to be treated, the amount of the surface-treated coating on the scaly pigment will be insufficient and the required effect of improving durability will not be obtained. is there. On the other hand, if the coating amount of phosphorus 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, but the preferable content of each component ion in the treatment agent aqueous solution in the method A is zirconium ion. 20 mg to 50 g /
It is preferable that at least one selected from 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 / liter, a sufficient amount of zirconium film may not be obtained, and if it exceeds 50 g / liter, 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 economical. If the concentration of phosphate ions is less than 1.2 mg / liter, a sufficient phosphorus film amount may not be obtained, and if it exceeds 120 g / liter, the effect reaches saturation and it is not economical.

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

The dispersion concentration of the scaly pigment used in the surface treatment in Method B in water is not particularly limited, but it is preferably 10 to 500 g per liter of the aqueous solution. If the weight of the scaly pigment per liter of the aqueous solution is less than 10 g, the ratio to the aqueous solution used is small and the treatment effect rate is low, which is uneconomical. Aqueous solution 1
If the weight of the scaly pigment per liter exceeds 500 g, the ratio to the aqueous solution used becomes high, and the stirring device required to maintain a suitable dispersed state becomes large, which is disadvantageous in terms of equipment.

The source of each component to be used is not particularly limited, but as the source of zirconium ions, zirconium fluoride, ammonium zirconate fluoride, and alkali metal fluoride zirconate can be used. One or more selected from salts can be used. As a source of trivalent chromium ions and hexavalent chromium ions, a water-soluble organic acid salt of trivalent chromium, an inorganic acid salt, or a partially reduced product of an aqueous solution of chromic anhydride, and dichromic acid, an ammonium salt of dichromic acid. One or more selected from alkali metal salts can be appropriately used. As a source of phosphate ions, various supply forms are possible, but from the viewpoint of economical efficiency, easy availability, etc.,
One or more selected from phosphoric acid, ammonium salt of phosphoric acid and alkali metal salt of phosphoric acid can be used.

In each of Method A and Method B, the scaly pigment treatment liquid prepared as described above is 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 scaly pigment having a durable luster excellent in moisture resistance, gloss retention and dispersibility. The treatment temperature and treatment time of the treatment liquid required for treating the scaly inorganic pigment powder particles should be determined by industrial profitability, whereby the necessary treatment temperature and treatment time can be appropriately determined. .

Although the film form of zirconium, chromium and phosphorus deposited on the surface of the pigment powder by the above treatment according to the present invention is not clear, according to XPS (X-ray photoelectron spectroscopy analysis), hexavalent zirconium / trivalent chromium. It is presumed that it has a complex form of oxide or hydroxide / phosphate.

In the present invention, whether or not the scale-like pigment obtained by the above treatment is collected by filtration, dried after washing with water, and the temperature are not particularly specified, but when dried at a temperature higher than 300 ° C., It is not preferable because it may cause a change in the color tone of the obtained flaky pigment.

The thus obtained scaly pigment having a durable luster is suitable for use by mixing in a coating material composed of a thermosetting resin or a lacquer type resin by a known method. The coating layer obtained by applying the scaly pigment-containing resin that has been subjected to such surface treatment to metal, plastic, wood, concrete, glass, etc., exhibits satisfactory durability and gloss under outdoor conditions. In particular, it retains sufficient water resistance as a coloring agent for exterior coatings for automobiles. Moreover, the surface-treated pigment obtained by the method of the present invention has excellent dispersibility and can be used as a paint exhibiting excellent designability without impairing the original color tone and gloss of the pigment.

[0034]

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 to these experimental conditions.

Example 1 Fluorinated zirconic acid was converted into zirconium ions in an amount of 0.
Containing 0.03 g / liter of trivalent chromium ions (produced by the tannic acid reduction method and using an aqueous solution of chromium chromate containing about 20% of trivalent chromium ions based on total chromium ions). And 1 liter of an aqueous solution containing 0.03 g / liter of phosphoric acid was prepared. Mica flakes are used as a base material, and aluminum is attached to a part of the base material by a sputtering method, and the grain size is 10 to 6
10 g of 0 μm metal-coated mica flakes were dispersed in the above aqueous solution with stirring, heated to 60 ° C. with continuous stirring, and kept at this temperature for about 30 minutes. The dispersion is then filtered, the solid product is filtered off, washed with water and washed with 110
It dried at 5 degreeC for 5 hours. The film formed on the pigment has 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 an alloy composition of Ni (10 atomic%), Cr (10 atomic%), Mo (2 atomic%), P.
(12 atom%), C (8 atom%), the balance Fe and inevitable impurities, and had a powder shape. The thickness of this powder is 1 to 4 μm, the aspect ratio (ratio of major axis to thickness) is 10 to 100, and the ratio of minor axis to major axis is 1 to 5,
The dimensions of the short diameter and the long diameter were 10 to 400 μm. Separately, an aqueous solution containing 2.5 g / liter of zirconium fluoride in terms of zirconium ion, 25 g / liter of chromium nitrate in terms of trivalent chromium ion, and 175 g / liter of phosphoric acid was prepared. Add to the powder dispersion and heat to 90 ° C while continuing to stir for approximately 3
Hold for 0 minutes. The dispersion was then filtered, the solid product was filtered off, washed with water and dried at 160 ° C. for 3 hours. Pigment 1
The film formed on the pigment per g is Zr: 0.033 m
g, Cr: 0.33 mg, P: 0.56 mg.

Example 3 200 g of a flake of metal oxide coated mica was dispersed in 900 ml of water. The mica flakes are coated with titanium dioxide in an amount of about 20% by weight of the mica flakes and have a particle size of 10 to 50 μm.
Met. Fluorozirconic acid is 0.8 g / liter in terms of zirconium ion and trivalent chromium ion is 1.5
% Aqueous solution of chromium chromate containing 2% / liter in terms of trivalent chromium ion and 1.5 g / liter of phosphoric acid, 100 ml of which is added to the above metal-coated mica flakes dispersion and stirring is continued. It was heated to 70 ° C. and kept for about 30 minutes. The dispersion was then filtered, the solid product was filtered off, washed with water and dried at 140 ° C. for 3 hours. The film formed on the obtained pigment was Z per 1 g of the pigment.
It was composed of r: 0.25 mg, Cr: 33 mg, P: 0.16 mg.

Example 4 Ammonium fluorozirconate was converted to zirconium ions at 0.9 g / liter, chromium nitrate was converted to trivalent chromium ions at 0.2 g / liter, and phosphoric acid was adjusted to 0.
1000 ml of an aqueous solution containing 4 g / l was prepared.
Separately, titanium dioxide is coated on a base material composed of mica flakes in an amount of about 46% based on the weight thereof, and a part of the base material is further coated with aluminum by a sputtering method to obtain a metal oxide / metal two-layer coating. Mica flakes (grain size 5 to 20 μm) 1
00 g was dispersed in the above aqueous solution, which was heated to 90 ° C. with stirring and held for about 10 minutes. Next, this dispersion was filtered, and a solid product was collected by filtration, washed with water, and dried at 140 ° C. for 2 hours. The film formed on the pigment is
It consisted of 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 about 60% by weight of iron oxide with mica flakes as a substrate and having a particle size of 5 to 20 μm, were dispersed in 500 ml of water. Separately, ammonium fluorozirconate was converted to zirconium ion at 180 mg / liter, chromium fluoride was converted to trivalent chromium ion at 54 mg / liter, and phosphoric acid was added at 4 mg / liter.
Prepare an aqueous solution containing 8 mg / l, 500 ml
Was added to the above-mentioned metal-coated mica flakes dispersion, and the mixture was heated to 90 ° C. with stirring and kept for about 10 minutes. The dispersion is then filtered and the solid product is filtered off, washed with water and dried at 150 ° C. for 2 hours.
Dried for hours. The film formed on the pigment contained Zr: 0.47 mg, Cr: 0.081 mg, P: 0.
It consisted of 065 mg.

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

EXAMPLE 7 A titanium dioxide / low order titanium oxide-coated mica flakes (particle size: 10 to 50 μm) coated with about 40% by weight of titanium dioxide and about 9% of low order titanium oxide on the basis of the mica flakes as a substrate.
m) 200 g were dispersed in 9000 ml of water. Separately, 100 ml of an aqueous solution containing 16 g / l of ammonium fluorozirconate 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 was added to the above metal-coated mica flakes dispersion. In addition, continue to stir and heat to 75 ° C for about 2
Hold for 0 minutes. The dispersion was then filtered, the solid product was filtered off, washed with water and dried at 110 ° C. for 4 hours. The film formed on the pigment has a Zr content of 5.2 mg, C per 1 g of the pigment.
It was composed of r: 1.2 mg and P: 2.9 mg.

Example 8 Obtained by coating the surface of a mica flake with about 45% by weight of titanium dioxide based on its weight, and further coating the surface with about 10% of metallic titanium by a sputtering method.
100 g of metal oxide / metal bilayer-coated mica flakes having a particle size of 10 to 20 μm were dispersed in 900 ml of water. Separately, 0.4 g of zirconium fluoride in terms of zirconium ion
/ Liter, chromic anhydride is 1 in terms of hexavalent chromium ion
An aqueous solution containing g / liter and 0.75 g / liter of phosphoric acid was prepared, and 100 ml of the aqueous solution was added to the above-mentioned metal oxide / metal bilayer-coated mica flakes dispersion, and the mixture was stirred at 60
It was warmed to ° C and held at this temperature for about 30 minutes. Next, this dispersion was filtered, and a 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 is Zr: 0.26 mg, Cr: 0.65 mg,
P: 0.15 mg.

Comparative Example 1 100 g of a metal oxide-coated mica flakes having a particle size of 10 to 50 μm, obtained by coating a substrate composed of mica flakes with about 20% by weight of titanium dioxide, was slurried with 1700 ml of distilled water. , Its pH is 6.0 by adding 2N sulfuric acid dropwise.
Adjusted to. Separately, 5% Chromium Chloride (CrCl ₃ )
32 ml of the aqueous solution was diluted with 100 ml of distilled water, and this solution was added to the above slurry at a constant rate for about 30 minutes. During the step of adding the aqueous solution of chromium (II) 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 to the slurry, the resulting slurry was filtered and the surface-treated pigment obtained was washed with water and dried at 110 to 120 ° C. for 1 hour. The film formed on the pigment has Zr: 0 mg, Cr: 0.04 per 1 g of the pigment.
mg, P: 0 mg.

Comparative Example 2 100 g of a metal oxide-coated mica flakes having a particle size of 5 to 20 μm obtained by coating a substrate composed of mica flakes with about 60% by weight of iron oxide was slurried with 1700 ml of distilled water. The pH was adjusted to 6.0 by adding 2N sulfuric acid dropwise. Separately, a 5% chromium chloride (CrCl ₃ ) solution 32
The ml was diluted with 100 ml of distilled water and this solution was added to the above slurry at a constant rate for about 30 minutes. During this addition operation of chromic chloride, its 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 has a Zr: 0 content per 1 g of the pigment.
mg, Cr: 0.04 mg, P: 0 mg.

Comparative Example 3 Comparative Example 1 was prepared by using 100 g of scaly powder obtained by precipitating silver in an island shape by electroless plating on the same titanium dioxide-coated mica flakes as the pigment used in Example 6. The same process was performed. The film formed on the pigment is Z per 1 g of pigment.
It was composed of r: 0 mg, Cr: 0.04 mg and P: 0 mg.

Comparative Example 4 The same treatment as in Comparative Example 2 was carried out using 100 g of the same metal oxide / metal double layer coated mica flakes as the pigment used in Example 7. The film formed on the pigment is Z per 1 g of pigment.
It was composed of r: 0 mg, Cr: 0.04 mg and P: 0 mg.

Comparative Example 5 Mica flakes coated with titanium dioxide and a lower titanium oxide having a particle size of 10 to 50 μm, which are the same as those of the pigment used in Example 3, were washed with water to prepare 1
It was 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-Based Base Paint 13 types of surfaces obtained in Examples 1 to 8 and Comparative Examples 1 to 5 Thermosetting acrylic melamine resin (manufactured by Dainippon Ink, trademark: Acridic 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 mixture of 34 parts by weight of Trademark: Super Beckamine L117-60 manufactured by Dainippon Ink Co., Ltd. to prepare 13 kinds of coating materials.

(B) Thermosetting acrylic melamine resin-based clear paint Trademark made by Dainippon Ink: Acridic A-310 (14)
0 part by weight) and a trademark of Dainippon Ink and Co., Ltd .: Super Beckamine L117-60 (50 parts by weight) were mixed to prepare a thermosetting acrylic melamine resin-based clear paint.

(C) Two-Component Curing Acrylic Urethane Resin-Based Base Coating The 13-component surface-coated pigments obtained in Examples 1 to 8 and Comparative Examples 1 to 5 were treated with a two-component curing acrylic urethane resin (Dainippon Ink Made, trademark: Acridic 54-480,10
0 part by weight, manufactured by Mitsui Toatsu, trademark: Orestar NP-10
15 parts by weight were added to 85 parts by weight of a solid content of the mixture (00, 20 parts by weight) to prepare 13 kinds of coating materials.

(D) Two-component curing type acrylic urethane resin-based clear paint Trademark made by Dainippon Ink: Acridic 54-480 (1
00 parts by weight) and a trademark manufactured by Mitsui Toatsu: Olester NP-
1000 (20 parts by weight) was mixed to prepare a two-component curable acrylic urethane resin clear paint.

(2) Preparation of performance test plate A cold-rolled steel plate (size = 70 × 150 mm) was subjected to a pretreatment for automobile coating, followed by cation electrodeposition and intermediate coating to obtain 52 intermediate coated plates. It was made. 26 of them next
Further, 13 kinds of acrylic melamine resin-based base paint (A), which was made into a paint 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-we
Acrylic melamine resin-based clear paint by the t method (B)
To a dry film thickness of 35 μm,
Two kinds of 13 kinds of test plates were prepared by heating and curing for 0 minutes. Similarly, 13 kinds of acrylic urethane resin-based base coating material (C) were applied so as to have a dry film thickness of 15 μm, respectively, and then acrylic urethane resin-based clear coating material (D) was dried by a wet-on-wet method to a dry film thickness of 35 μm.
And heat it at 80 ℃ for 30 minutes to cure it.
Two pieces of each of three types of test plates were produced.

(3) Performance test conditions [High temperature water resistance test] Half of the 26 types of test plates (12 types of coating system A / B and 12 types of coating system C / D) manufactured as described above in the longitudinal direction were heated at 80 ° C. After being immersed in warm water for 24 hours, the change in the coated surface between the immersed portion and the non-immersed portion was visually determined.

[Accelerated weathering test] Test plate 2 similar to the above
Four types of accelerated weather resistance tests were performed for 1000 hours with a sunshine weather ohmmeter, and the gloss retention rate (Δ
G) and color difference (ΔE) were measured.

The results of the high temperature water resistance test and the accelerated weather resistance test are shown in Table 1.

[0056]

[Table 1]

As is apparent from Table 1, all of the scaly 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,
Also in the manufacturing process, Comparative Examples 1 to 5 require complicated chemical solution management, while Examples 1 to 8 according to the present invention have the advantage that good products can be obtained by a simple method. Is.

[0058]

EFFECTS OF THE INVENTION The scaly pigment surface-treated by the method of the present invention has extremely excellent high-temperature water resistance and weather resistance and has a durable luster, and is suitable for use in the exterior coating of automobile bodies and other applications. It is useful. Further, according to the method of the present invention, it is possible to efficiently carry out a surface treatment for imparting durable gloss to the flaky pigment.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mikio Asai 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Corporation (72) Inventor Hiroshi Ito 1 Toyota Town, Aichi Prefecture, Toyota Motor Corporation

Claims (6)

[Claims] 1. 1 g of this pigment on the surface of scaly pigment particles
A surface treatment method for imparting durable luster to a scaly 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 elements. 2. To form the surface film, the flaky pigment is dispersed in water at a rate of 10 to 500 g per liter of water, and 20 mg to 50 g of zirconium ion is added to an aqueous dispersion of the pigment. 20 liters of at least one selected from trivalent chromium ion and hexavalent chromium ion
mg to 50 g / liter, and phosphate ion 1.2 mg
An aqueous solution of a treating agent containing ˜120 g / liter is added at a rate of 1 to 250 ml per liter of an aqueous dispersion of the pigment, and the scaly pigment is brought into contact with the treating agent to collect the surface-treated pigment obtained. Collecting, washing with water, and drying.
The surface treatment method described in. 3. To form the surface coating, 0.5 mg to 10 g / liter of zirconium ion and 0.5 mg to 10 g / liter of at least one selected from trivalent chromium ion and hexavalent chromium ion. 10 to 500 g of the scaly pigment per 1 liter of an aqueous treatment agent solution containing 0.3 mg to 40 g / liter of phosphate ions
The surface treatment method according to claim 1, wherein the surface-treated scale pigments obtained by dispersing at a ratio of 1 are collected from the aqueous solution by filtration, washed with water, and dried. 4. The scaly pigment comprises (1) mica flakes, (2) aluminum flakes, (3) amorphous alloy flakes, (4) micaceous iron oxide (MIO) powder, and (5) scaly powder granules. A powder comprising a core body made of an inorganic material and a surface layer coating the surface of the core body and made of at least one selected from metals, alloys and metal oxides. And a surface layer that covers the surface of the core and is laminated in any order, and is composed of at least one metal or alloy film layer and at least one metal oxide film layer. And (7) a core body made of a scale powder granular inorganic material, and a composite core body made of a scale powder granular inorganic material particles and a metal oxide film layer formed on the surface thereof. At least one core 4. The powder according to claim 1, which is formed on the surface of the core body in an island shape and is composed of at least one kind selected from a powder consisting of an island layer composed of at least one kind selected from metals and alloys. The surface treatment method according to item 1. 5. The zirconium ion is supplied from at least one selected from fluorozirconic acid, ammonium salt of fluorozirconic acid or alkali metal salt, and selected from trivalent chromium ion and hexavalent chromium ion. At least one is a water-soluble organic acid salt of trivalent chromium, an inorganic acid salt, or a partially reduced product of an aqueous solution of chromic anhydride, and dichromic acid, an ammonium salt of dichromic acid,
2. The compound 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, ammonium salts of phosphoric acid, and alkali metal salts of phosphoric acid. 5. The surface treatment method according to any one of 1 to 4. 6. The coating containing zirconium, chromium, and phosphorus has a zirconium content of 0.05 to 15 mg and a chromium content of 0.1 per 1 g of the pigment in terms of element weight.
The surface treatment method according to claim 1, containing -25 mg and 0.03-10 mg of phosphorus.