JPH09188830A - Highly bright metallic pigment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pigment for metallic coating which exhibits a high-grade metallic feel and, in the form of a coating, has good adhesion. SOLUTION: This metallic pigment comprises a glass flake having an average particle diameter o5 10 to 300μm and an average thickness of 1 to 20μm and a 50 to 200Å-thick metallic thin layer formed by sputtering. The metallic thin layer comprises Au, Ag, Cu, Al or an alloy thereof. Therefore, even when the thickness of the metallic thin layer is small, it is possible to provide a coating surface having satisfactory metallic feel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metallic pigment blended with a paint for forming a metallic paint film on furniture, automobile bodies, home appliances and the like.

[0002]

2. Description of the Related Art A coating film using a metallic paint shines when the incident light from the outside is reflected on the scale-like metallic pigment contained in the coating film and shines in combination with various color tones of the coating film. It has an excellent appearance. By taking advantage of this unique surface appearance, metallic paints are widely adopted for car bodies such as automobiles and motorcycles. Aluminum foil as metallic pigment,
Metal foils such as tin foil and stainless steel foil, mica foil, and plate-shaped iron oxide are used. Recently, glass flakes plated with electroless nickel or electroless silver are commercially available as metallic pigments exhibiting excellent glitter. Using this metallic pigment, a metallic paint (Japanese Patent Laid-Open No.
No. 359937, Japanese Unexamined Patent Publication No. 5-17710, etc.), retroluminescent paint (see Japanese Unexamined Patent Publication No. 5-179174), adhesive tape excellent in sparkling effect (see Japanese Unexamined Patent Publication No. 5-320588), etc. Being manufactured.

[0003]

SUMMARY OF THE INVENTION In order to develop good glitter, it is necessary to perform silver plating as thick as 500 to 2,000 Å, which consumes a large amount of expensive silver. Moreover, when Ag coating is performed by electroless plating, many steps such as pretreatment, washing with water, filtration, and waste liquid treatment are required, resulting in high manufacturing cost. Recently, in order to further improve the designability, development of a metallic pigment having more excellent luster is desired. However, it has been extremely difficult to produce a metallic pigment having higher luster by the conventional method. Furthermore, the conventional metallic pigments are almost achromatic colors such as white and gray, which is also a problem from the viewpoint of improving the design. On the other hand,
Along with the diversification of tastes, highly bright metallic pigments colored in gold or red have been desired. The present invention has been devised to meet such requirements, by applying a metal thin film to the glass flakes by a sputtering method, exhibiting excellent glitter compared to conventional metallic pigments, and at low cost. It is an object to provide a metallic pigment that can be colored.

[0004]

The highly bright metallic pigment of the present invention has an average particle size of 10 in order to achieve its object.
The surface of the glass flakes having an average thickness of 1 to 20 μm and a thickness of 50 to 200 μm is coated with a metal thin film having a thickness of 50 to 200 Å by a sputtering method. Au, Ag, Cu, Al or alloys thereof are used as the metal thin film.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The glass flakes used in the present invention are scaly particles having an average particle size of 10 to 300 μm and an average thickness of 1 to 20 μm. If the average particle size is less than 10 μm, it is difficult to orient in a certain direction in the coating film, and it is difficult to produce a bright feeling. However, if the average particle diameter exceeds 300 μm, a fine metallic feeling cannot be obtained. Generally, 20-100μ
The range of m is a preferable average particle size. It is difficult to manufacture glass flakes having an average thickness of less than 1 μm.
If the average thickness exceeds μm, it becomes close to the thickness of the coating film and deteriorates the smoothness of the coated surface. The average thickness of the glass flakes is preferably in the range of 5 to 10 μm.

The glass flakes include elemental glass, hydrogen-bonded glass, oxide glass, fluoride glass, chloride glass, sulfide glass, carbonate glass, nitrate glass,
Sulfate glass or the like can be used. From the viewpoint of price and performance, oxide glasses such as silicate glass, alkali silicate glass, soda lime glass, lead glass, barium glass and borosilicate glass are preferable. The metal coated on the surface of the glass flakes may be of any type as long as it can form a uniform thin film. For example, Au, Ag, Cu, Al or alloys thereof are listed. Among them, Ag exhibits the most excellent light ray reflection property. When Au or Cu is used, a colored metallic pigment is obtained.

In the present invention, since the metal thin film is coated by the sputtering method, it is possible to easily coat various alloys which are difficult by the electroless plating method. For example, a 60% Au-40% Ag alloy is used as a low-cost material that retains the same corrosion resistance as Au.
The 80% Ag-20% Sn alloy forms a thin film of tin oxide and exhibits excellent resistance to sulfidation and discoloration. 60% Cu-40%
The Zn alloy has excellent corrosion resistance and can be colored gold. 95% Al-5% Si alloy hardens the film,
Improves wear resistance. This metallic pigment is added to the coating film to form a metallic coating film,
It can be mixed with printing ink and used as a reflection tape, display material, signboard, etc. It can also be mixed with various plastic products and used as a weld line prevention material.

As a coating method, besides the sputtering method, an ion plating method, a vacuum vapor deposition method and the like are possible, but the powder sputtering method developed by the present inventors is the most suitable. Generally, it is said that the thicker the coating, the larger the surface irregularities and the lower the glitter. For example, in the electroless plating method, the entire surface of the powder cannot be uniformly coated unless the coating is thicker than 1,000 Å.
Even a thin film of less than 0Å can be uniformly coated on the entire surface. Therefore, by the sputtering method, it becomes possible to impart more excellent glitter. Moreover, since the amount of Ag coating can be reduced, the manufacturing cost can be reduced.

In the sputtering method, since the metal atoms excited to the plasma state repeatedly collide with the surface of the glass flakes at a high speed, the density of nuclei generated during the formation of the metal film becomes extremely high, and the glass flakes with a small amount of metal. The surface of can be uniformly coated. In this regard, in the electroless plating method,
The surface of the glass flakes is previously activated with palladium or the like, and the portion where the palladium is attached becomes a point of generation of nuclei for forming a metal film during electroless plating. It is presumed that the attachment density of palladium, which is a physical adsorption phenomenon, is much smaller than the collision density of metal atoms excited in the plasma state in the sputtering method. Due to this difference, the thin metal film necessary for uniformly covering the entire surface of the glass flake can be thinned by the sputtering method.

After uniformly coating the surface of the glass flakes with a metal by the sputtering method, stearic acid and oleic acid are used to improve the dispersibility in the paint, the adhesion to the resin, the discoloration of the coating film and the corrosion resistance. Surface treatment may be carried out with various fatty acids such as and various chelating agents such as benzotriazole and triazinethiol, or various coupling agents. Specific examples of the coupling agent include γ-
Aminopropyltriethoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, titanium-based coupling agent , Zirconia-based coupling agents, aluminum-based coupling agents and the like. The glass flakes coated with a metal thin film are compounded in the resin at a ratio of 0.1 to 30% by weight based on 100 parts by weight of the vehicle component (solid content). If this blending amount is too large, it becomes difficult to obtain a deep and high-grade metallic feeling. The upper limit of the amount used is not particularly limited, but is appropriately determined depending on the type of resin, the required physical properties of the molded product, etc., and is usually up to 20% by weight, preferably up to 5% by weight To be done.

As the vehicle component, a curable resin composition containing a base resin and a crosslinking agent as main components is preferable. The base resin includes acrylic resin, polyester resin, alkyd resin having a crosslinkable functional group, and a transparent resin is preferable as much as possible. As the cross-linking agent, a methylol- or alkyl-etherified melamine resin, a urea resin, and a polyisocyanate compound are preferable. Self-curing resin and thermosetting resin can also be used as the base resin. It is also possible to use a resin colored with a dye or pigment. Further, the pigment is mixed with the resin using an organic solvent for paint, water or the like. For the sputtering method of coating various metals on the glass flake surface,
The powder sputtering apparatus developed by the present inventors is preferably used. For example, a rotating container containing powder is rotated to form a fluidized bed inside the rotating container. An apparatus for sputtering the fluidized bed (see Japanese Patent Application Laid-Open No. 2-153068), an apparatus for sputtering a repeated falling flow of powder (Japanese Patent Application Laid-Open No. 62-250172) and the like are used.

[0012]

【Example】

Example 1 In this example, a powder sputtering apparatus having the equipment configuration shown in FIG. 1 was used, and the average particle size was 10 μm.
A transparent soda lime glass flake having an average thickness of 1 μm was coated with a 50 Å-thick Au coating. In this device,
Rotating drum 1 with inner diameter of 200 mm and axial length of 200 mm
Is supported by two rolls 2, and one of the rolls 2 is
It is rotating at. Inside the rotating drum 1, the frequency 1
Magnetron type with 3.56MHz and output of 1.5KW
Two Au sputtering sources 4 targeting 99.9% by weight of Au are arranged, and Au is sputtered on the introduced transparent glass flakes 5.

A decompression processing chamber 7 having a heating coil 6 on the outer periphery is arranged above the rotary drum 1, and the bottom of the decompression processing chamber 7 is connected to the rotary drum 1 by a supply pipe 9 equipped with a valve 8. ing. The portion of the supply pipe 9 on the side closer to the valve 8 is a double pipe in which an Ar gas introduction pipe 10 is inserted. The supply pipe 9 is inserted inside from the side surface of the rotary drum 1 and has a tip extending to the bottom of the rotary drum 1.
A branch pipe 11 is provided below the valve 8 of the supply pipe 9, and the tip of the branch pipe 11 is connected to a fluid jet mill 12. Further, the outlet side of the fluid jet mill 12 is connected to the upper portion of the decompression processing chamber 7 via a circulation pipe 13. Valves 14 and 15 are attached to the branch pipe 11 and the circulation pipe 13, respectively, and the solid-gas separation device 1 is attached to the circulation pipe 13.
6 are connected.

100 glass flakes 5 on the rotary drum 1
g, and the decompression chamber 7 was decompressed to 3.0 × 10 ⁻³ Pa, and then Ar gas was introduced from the Ar gas introduction pipe 10 at 15 cm ³ /
Introduced at a flow rate of minutes, transparent glass flakes 5 branch pipe 1
1, suction-transferred to the decompression processing chamber 7 via the fluid jet mill 12 and the circulation pipe 13. Then, it was heated to 200 ° C. for 30 minutes by the heating coil 6 in the decompression processing chamber 7, and dried and degassed. Then, after completely replacing the atmosphere of the rotating drum 1 with Ar gas, the transparent glass flakes 5 in the decompression processing chamber 7 are dropped from the supply pipe 9 to the rotating drum 1 while rotating the rotating drum 1 at a rotation speed of 5 rpm. , 3.0 x 1
Sputtering was performed by the sputtering source 4 in a reduced pressure atmosphere of 0 ⁻¹ Pa. After 10 minutes, the sputtering was stopped, the decompression chamber 7 was decompressed, Ar gas was introduced into the rotary drum 1 from the Ar gas introduction pipe 10, and the transparent glass flakes 5 were passed through the fluid jet mill 12 to decompress the chamber 7. Then, the transparent glass flakes 5 agglomerated during sputtering were loosened into individual particles. The transparent glass flakes 5 returned to the decompression processing chamber 7 had a thickness of 10Å
Of Au was coated. This sputtering operation
By repeating the process once, the Au film was made to have a thickness of 50 Å and then collected from the solid-gas separation device 16.

Examples 2 to 8: By the same procedure as in Example 1, 60% Au-40% Ag alloy, Ag, 80% Ag-
20% Sn alloy, Cu, 60% Cu-40% Zn alloy,
Al, 95% Al-5% Si alloy 50Å, 1 respectively
00Å, 100Å, 150Å, 150Å, 200Å, 2
The surface of the transparent glass flakes was coated to a thickness of 00Å. Comparative Example 1: By the same procedure as in Example 1, the average particle size was 5 μm.
The surface of transparent soda-lime glass flakes having an average thickness of m and an average thickness of 1 μm was coated with Ag to a thickness of 30Å. Comparative Example 2: By the same procedure as in Example 1, an average particle size of 40
The surface of transparent soda-lime glass flakes having a thickness of 0 μm and an average thickness of 30 μm was coated with Ag to a thickness of 300 Å.

Comparative Example 3: On the surface of transparent soda-lime glass flakes having an average particle size of 100 μm and an average thickness of 5 μm, 2
Ag was electrolessly plated to a thickness of 00Å. In electroless plating, stannous chloride 40g / l, hydrochloric acid 40g / l
500 g of transparent glass particles was added to 1 liter of an aqueous solution containing 1 and sensitizing was performed by stirring at 60 ° C. for about 20 minutes, and then the transparent glass particles were thoroughly washed with deionized water. Next, palladium chloride 2g / l, hydrochloric acid 20g / l
The transparent glass particles were added to 1 liter of an aqueous solution containing a, and stirred at room temperature for about 20 minutes. After this activation treatment, it was washed again with deionized water, and then electroless Ag plating was performed using the following two types of solutions. (1) Preparation of Ag ammonia solution: 100 m of deionized water
8 g of silver nitrate was added to and dissolved in 10 l of deionized water.
A solution prepared by dissolving 4 g of potassium hydroxide in 0 ml was mixed. The resulting solution tended to gradually turn brown.
Further, about 80 ml of ammonium hydroxide was added, and the mixture was stirred until the color of the solution became transparent.

(2) Preparation of reducing solution: deionized water 200
18 ml of table sugar was added to and dissolved in ml. About 4 ml of concentrated nitric acid was added to this solution, and the resulting solution was boiled for another 30 minutes to convert table sugar into invert sugar. And
A reducing solution was prepared by cooling the solution to room temperature. Into 300 ml of silver ammonia solution, add 500 g of pretreated transparent glass particles and stir at room temperature for 25 hours.
The transparent glass particles were electroless silver plated by adding 200 ml of the reducing solution at a slow rate of drops / minute.
After the silver plating was completed, the transparent glass particles were thoroughly washed with water and dried. As a result, a 200 Å-thick Ag film was formed on the surface of the transparent glass particles.

Comparative Example 4: By the same procedure as in Comparative Example 3,
An Ag thin film having a thickness of 1,000 liters was electrolessly plated on the surface of the transparent glass flakes. A total of 12 samples of metallic pigments obtained in each of the above examples were used to prepare coated steel sheets under the following conditions. To 10 parts by weight of each metallic pigment, 8 parts by weight of toluene was added to uniformly disperse the pigment in toluene. Next, a thermosetting acrylic resin varnish (Mitsui Toatsu Chemical Co., Ltd. Almatex 44
8-O) 60 parts by weight, melamine resin varnish (Mitsui Toatsu Chemical Co., Ltd. Uban 20N-60) 12 parts by weight and 65% toluene-35% n-butanol mixed solvent 15 parts by weight are added, and the mixture is stirred with a disper for 30 minutes. Then, the paint was prepared.

Plate thickness 0.8 mm, width 300 mm, length 50
After pretreatment of 0 mm polished steel plate with phosphate treatment, electrodeposition coating is performed using cationic electrodeposition coating (Nippon Paint Co., Ltd., Power Top U-30), heating at 160 ° C. for 30 minutes and drying. An undercoat coating film having a film thickness of 20 μm was formed. Then, an intermediate coating material (Olga P-2 Gray manufactured by Nippon Paint Co., Ltd.) was applied according to a conventional method and heated at 140 ° C. for 30 minutes to form an intermediate coating film having a dry film thickness of 35 μm. Dry film thickness of 15 μm on the formed intermediate coating film
A paint containing a metallic pigment was applied by electrostatic spraying with a spray gun. The metallic paint is a paint thinner (Nippe 29 manufactured by Nippon Paint Co., Ltd.).
It was diluted with 8) and the viscosity was adjusted to 20 seconds at 15 ° C. in a No. 4 Ford cup. After applying metallic paint, clear paint is wet on wet (Nippon Paint Co., Ltd. Super Rack 128M-
1) was applied and heated at 140 ° C. for 30 minutes to give a dry total film thickness of 140 μm.

In this way, coated steel sheets were prepared using the paint containing the metallic pigment prepared in each example. With respect to each coated steel sheet, the metallic feeling and the adhesion to the resin forming the coating film were investigated by the following methods. The metallic feeling was investigated by using a digital variable angle gloss meter (UGV-5K manufactured by Suga Test Instruments Co., Ltd.) as a 60-degree specular reflectance. The adhesiveness was evaluated by observing the appearance of the coating film after immersing it in warm water of 40 ° C. for 10 days with the naked eye and checking for discoloration or blistering. As can be seen from the investigation results in Table 1, the coated steel sheets obtained using the metallic pigments of Examples 1 to 8 according to the present invention are compared with the coated steel sheets using the metallic pigments of Comparative Examples 1 to 4. As a result, the surface state showed practically sufficient adhesion and exhibited an extremely excellent metallic feeling. Further, it was confirmed that a metallic feeling superior to that of Comparative Example 4 in which Ag was thickly coated was obtained, and Ag consumption could be reduced.

[0021]

[Table 1]

[0022]

As described above, the metallic pigment of the present invention is a glass flake coated with a metal thin film by a sputtering method, and even if the film thickness is thin, the entire surface of the glass flake can be uniformly coated. it can. Therefore, even if the metal thin film is thin, a high quality metallic feeling can be obtained. This metallic pigment imparts an extremely excellent metallic feel by being mixed with a paint and applied on a steel plate. Therefore, it is used in a wide range of fields such as furniture, car bodies, and painting of home appliances. Further, it can be mixed with printing ink and used as a reflection tape, a display material, a signboard, or the like, and can be kneaded into various plastic products to be used as a weld line generation preventing material.

[Brief description of the drawings]

FIG. 1 is a powder sputtering apparatus used in this example.

[Explanation of symbols]

1: rotating drum 2: roll 3: motor
4: Sputtering source 5: Transparent glass flakes 6: Heating coil
7: Decompression treatment chamber 8: Valve 9: Supply pipe 10: Ar gas introduction pipe 11: Branch pipe 12: Fluid jet mill 13: Circulation pipe 1
4, 15: valve 16: solid-gas separation device

Claims (2)

[Claims] 1. A glass flake having an average particle size of 10 to 300 μm and an average thickness of 1 to 20 μm is coated with 50 to 20 μm.
A high-brightness metallic pigment formed by coating a 0Å metal thin film by sputtering. 2. The metal thin film according to claim 1, wherein the metal thin film is Au, Ag,
A highly bright metallic pigment which is Cu, Al or an alloy thereof.