JPH10316883A - Metallic pigment having excellent weather resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metallic pigment having excellent brightness and weather resistance. SOLUTION: This metallic pigment has a coating layer composed of an Fe or Ni-based alloy having austenite structure on the surface of a flaky substrate. The Fe or Ni-based alloy is e.g. SUS304, SUS309S, SUS310S, SUS316, Hastelloy B, Hastelloy C or Hastelloy G. The coating layer is preferably formed to a thickness of 50-300 Å by sputtering. The pigment is mixed into a coating material, a printing ink or various molded plastic articles to form a surface having excellent brightness and weather resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to metallic paints and printing inks used for painting automobile bodies and exterior building materials.
The present invention relates to a metallic pigment which is blended in a resin compound or the like and has a surface with excellent glitter.

[0002]

2. Description of the Related Art A coating film formed using a metallic paint has a scaly metallic surface which reflects externally incident light by a flaky metallic pigment contained in the coating film.
The reflection of light, together with each color tone of the coating film, presents a unique appearance excellent in design. Utilizing such characteristics, metallic paints are used for vehicle bodies such as automobiles and motorcycles, and building materials requiring design properties. Metallic pigments such as aluminum flakes, copper flakes, and stainless flakes, mica, and plate-like iron oxide have been conventionally used as metallic pigments mixed with this type of paint. But,
None of these pigments can be said to be metallic pigments having both glitter and weather resistance.

[0003] For example, metal foils exhibit some glitter but are inferior to glass flakes. The difference in glitter is considered to be due to the manufacturing method. Since glass flakes are produced by cooling and solidifying from a liquid state, they have an extremely smooth surface. On the other hand, since the metal foil is manufactured by machining such as a ball mill and a stamp mill, fine irregularities due to the machining remain on the surface and cause irregular reflection. In addition, aluminum flakes and copper flakes have a drawback in that they are slightly inferior in corrosion resistance. On the other hand, non-metallic flakes such as mica and plate-like iron oxide are excellent in corrosion resistance, but they have fine irregularities formed on the surface, so that their glitter is considerably inferior to glass flakes. At present, glass flakes which have been subjected to electroless nickel plating or electroless silver plating are commercially available as metallic pigments having the best glitter. A metallic paint using this glass flake is disclosed in, for example, JP-A-4-359.
937, JP-A-5-17710, and the like.

[0004]

In order for glass flakes coated with Ni or Ag by electroless plating to exhibit sufficient brilliancy, plating of a considerably thick film of 500 to 2000 ° is required. However, expensive materials such as Ni and A
If g is plated thickly, the product cost will be high.
In addition, electroless plating requires a number of steps such as pretreatment, water washing, filtration, and waste liquid treatment, which causes an increase in manufacturing costs. Further, Ag is easily oxidized, and easily discolors to black when reacted with sulfide. Therefore, the weather resistance was insufficient for use as a metallic pigment for exterior building materials. On the other hand, with the deterioration of the environment, high weather resistance has also been required for metallic pigments. For these reasons, there is a strong demand for the development of a highly brilliant metallic pigment having excellent weather resistance for automobile bodies and exterior building materials. However, it is extremely difficult to produce a metallic pigment with improved weather resistance and brilliancy even more than in the prior art. The present invention has been devised to meet such a demand, and by forming a uniform coating layer of an Fe-based alloy or a Ni-based alloy having excellent corrosion resistance on the surface of a flaky substrate by a sputtering method, An object is to provide a metallic pigment having improved weather resistance and excellent glitter.

[0005]

In order to achieve the object, a metallic pigment of the present invention has a scale-like substrate and an Fe-containing austenitic structure covering the surface of the scale-like substrate.
It is characterized by comprising a coating layer of a base alloy or a Ni base alloy. The scaly substrate has an average particle size of 10 μm to 300 μm,
Pearl mica or glass flakes having an average thickness of 0.1 μm to 20 μm are used. For example, austenitic stainless steel is used for the Fe-based alloy. As the Ni-based alloy, an alloy containing 50% by weight or more of Ni is used.
The Fe-based or Ni-based alloy is formed on the surface of the scaly substrate as a coating layer having a thickness of 50 to 300 ° by a sputtering method.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The scaly substrate used in the present invention includes:
There are pearl mica, glass flake, aluminum flake, graphite, molybdenum disulfide, plate-like iron oxide and the like. Above all, the average particle size is 10 μm to 300 μm, and the average thickness is 0.1 μm.
Pearl mica and glass flakes of 1 μm to 20 μm are preferred. A scaly substrate having an average particle size of less than 10 μm is not easily oriented in a certain direction in the coating film, and does not exhibit a sufficient glitter. The average particle size of the scaly substrate is generally preferably in the range of 20 μm to 100 μm in consideration of availability. Incidentally, pearl mica which is commercially available as a paint pigment has a thickness of 0.1 to 1 μm, and glass flakes which are used as a filler for plastic molded products often have a thickness of 1 to 20 μm.

In the present invention, the surface of the scaly substrate is coated with an Fe-based alloy or Ni-based alloy having an austenitic structure. The outermost layer of the coating layer of the Fe-based or Ni-based alloy is covered with a thin passive film of several tens of atomic layers that is naturally generated by contact with air. By the effect of this passivation, chromium hydroxide treatment, zirconia hydroxide treatment, silica treatment,
Even without post-treatment such as alumina treatment, corrosion resistance and weather resistance are significantly improved while maintaining high gloss. Such a post-treatment is usually performed by a wet method using an acid-alkali reaction, but it is difficult to control the concentration of the solution and the reaction temperature in order to obtain a stable quality product. Many processes such as filtration, drying, classification, and waste liquid treatment are required. Therefore, the elimination of post-processing leads to a significant reduction in manufacturing costs.

[0008] Examples of Fe-based alloys having an austenitic structure include SUS304, SUS309S, and SUS310.
S, SUS316, SUS317, SUS321, SU
S347 and the like are used. The type of these alloys is selected depending on the desired corrosion resistance, heat resistance, and the like. In addition,
Other austenitic stainless steels including C, N, Si, Al, Ti, Mo, etc. can also be used. Examples of Ni-based alloys having an austenitic structure include Hastelloy B, Hastelloy C, Hastelloy G, Hastelloy H, Hastelloy N,
Hastelloy X, Hastelloy XR, an Inconel-based Ni-based alloy, or the like is used. Fe with austenitic structure
System or Ni-based alloy is 50 to 300 ° (preferably 10 to 300 °).
0 to 200 °) on the surface of the scaly substrate.
If the film thickness is less than 50 °, the scale-like substrate cannot be uniformly coated, and sufficient glitter cannot be obtained. Conversely, 30
A thick film thickness exceeding 0 ° can completely cover the surface of the scaly substrate, but does not show improvement in weather resistance, brilliancy, etc. corresponding to the increase in the film thickness, and rather increases the production cost.

The coating layer of the Fe-based alloy or the Ni-based alloy can be formed by a sputtering method, an ion plating method or the like. Among them, the powder sputtering method developed by the present inventors is optimal. On the other hand, a coating layer of an alloy having an austenitic structure cannot be formed by electroless plating.
Further, in the vacuum evaporation method, since the melting points and vapor pressures (under high vacuum conditions) of the metals constituting the alloy are different from each other, it is extremely difficult to obtain a coating having a constant composition. A CVD method or the like in which the temperature at the time of coating exceeds 600 ° C. is not preferable because the glass flake itself softens. The coating layer of the alloy having the austenitic structure is easily formed on the surface of the scaly substrate when the powder sputtering device developed by the present inventors is used. For example, an apparatus (JP-A-2-153068) for sputtering metal onto a fluidized bed formed by rotating a container containing powder is used.

[0010] Sputtering is usually performed in an Ar atmosphere. At this time, the introduction of N ₂ containing gas during sputtering, N ₂ gas is austenite elements dissolved in the above thermal equilibrium, austenite is further promoted. At this point, the atmosphere during sputtering is 1-1.
It is preferable to introduce an Ar gas containing 0% by volume of N ₂ gas. In general, it is said that if the coating is not thickened to some extent, the unevenness of the surface is large, and the glitter is reduced. For example, in the electroless plating method, it is said that the entire surface of the powder cannot be uniformly coated unless the coating is made as thick as 1000 ° or more. On the other hand, in the sputtering method, even if less than 300 °, the entire surface can be uniformly coated, so that more excellent glitter is imparted. The obtained metallic pigment is mixed with a paint and used for metallic coating. It can also be mixed with printing ink and used for reflective tapes, various display materials, signboards, road signs and the like. Furthermore, it can be kneaded into various plastic molded products and applied as an agent for preventing the generation of weld lines.

[0011]

In the sputtering method, a phenomenon in which a plurality of metal atoms constituting an alloy excited to a plasma state collide with the surface of the flaky substrate at high speed is repeated. Oxides such as TiO ₂ , SiO ₂ and Al ₂ O ₃ constituting pearl mica and glass flakes react with Fe-based or Ni-based alloy due to the collision energy, and Fe-Ti-
Compounds such as O, Ni-Si-O and Cr-Al-O are formed. As a result, the formed coating layer has excellent adhesion to the scaly substrate. In addition, the generated compound layer becomes a nucleus serving as a starting point for forming the coating layer, and a large number of nuclei are formed at an extremely high density. Therefore, a small amount of F
The surface of the scaly substrate can be uniformly coated with an e-based or Ni-based alloy, and the formed coating layer also has a dense structure without defects.
As a result, excellent weather resistance and glitter are imparted. On the other hand, in the electroless plating method, a pretreatment for activating the surface of the scaly substrate with palladium or the like in advance is performed. The palladium-adhered portion serves as a nucleation point for film formation during electroless plating. However, since palladium is attached by a physical adsorption phenomenon, the adhesion strength is lower than that of the sputtering method. Moreover, the adhesion density of palladium is much smaller than the collision density of metal atoms excited into a plasma state. Therefore, the formed coating layer tends to be rough,
From this, it is presumed that the glitter is inferior.

[0012]

【Example】

Example 1: Using the powder sputtering apparatus shown in FIG.
SUS is applied on the surface of silver pearl mica pigment (Mal Co., average particle size: 10 μm, average thickness: 0.1 μm)
304 alloy (74% by weight Fe-18% by weight Cr-8% by weight Ni) was coated to form a coating layer having a thickness of 200 °. The powder sputtering equipment has an inner diameter of 200 mm,
A rotary drum 1 having a length of 200 mm in the axial direction is
, And one of the rolls 2 is rotated by a motor 3. Inside the rotating drum 1, two SUS304 alloy sputtering sources 4 (frequency 13.
5MH _Z, output magnetron type 1.5KW) are arranged, the pearl mica pigment 5 was charged SUS304
The alloy is sputtered.

Above the rotary drum 1, a decompression processing chamber 7 having a heating coil 6 on its outer periphery is arranged. The bottom of the decompression chamber 7 is connected to the rotary drum 1 via a supply pipe 9 having a valve 8. A gas supply pipe 10 having a double pipe structure is inserted into the supply pipe 9 at a position below the valve 8. The gas supply pipe 10 is inserted into the inside of the rotary drum 1 from a side surface, and has a tip extending to the bottom of the rotary drum 1. A branch pipe 11 is provided in the supply pipe 9 at a position below the valve 8, and a tip of the branch pipe 11 is connected to the fluid jet mill 12. The outlet side of the fluid jet mill 12 is connected to the upper part of the decompression processing chamber 7 via the circulation pipe 13. A valve 14 and a valve 15 are incorporated in the branch pipe 11 and the circulation pipe 13, and a solid-gas separation device 16 is connected to the circulation pipe 13.

The rotating drum 1 is filled with 10 pearl mica pigments 5
0 g, and the pressure reduction chamber 7 was set to 3.0 × 10^-3Reduced pressure to Pa
After that, 14 cm of Ar gas was supplied from the gas introduction pipe 10.^Three /
Minutes, N _Two 1cm of gas^Three / Min flow rate. Pearl
The mica pigment 5 is divided into a branch pipe 11, a fluid jet mill 12, and
In the decompression processing chamber 7 via the circulation pipe 13,
It was heated to 00 ° C. for 30 minutes, dried and degassed. Then, times
Drop the pearl mica pigment 5 onto the transfer drum 1
While rotating the system 1 at a rotation speed of 5 rpm, 3.0 ×
10^-1Under the reduced pressure of Pa, the sputtering source 4
Taling. Stop sputtering after 10 minutes,
The pressure in the vacuum processing chamber 7 is reduced, and the gas introduction pipe 10
r and N_Two Of pearl mica pigment 5
Suction returned to the decompression processing chamber 7 via the body jet mill 12,
The pearl mica pigment 5 that has been lumped during sputtering
The individual particles were loosened as much as possible. Return to decompression chamber 7
5 m thick SUS30
Four alloy coating layers were formed. This sputtering operation
By repeating the operation 40 times, the SUS304 alloy
After growing the coating layer to a thickness of 200 mm, a solid-gas separator
Collected from 16.

Examples 2 to 7: In the same procedure as in Example 1,
As shown in Table 1, the following F
An e-based and Ni-based alloy coating layer was formed. SUS309S alloy (66 wt% Fe-22 wt% Cr
-12% by weight Ni) SUS310S alloy (55% by weight Fe-25% by weight Cr)
-20% by weight Ni) SUS316 alloy (67.5% by weight Fe-18% by weight C)
r-12 wt% Ni-2.5 wt% Mo Hastelloy B alloy (67 wt% Ni-28 wt% Mo-
Hastelloy C alloy (58% Ni-22% Cr-
13% by weight Mo-4% by weight Fe-3% by weight W) Hastelloy G alloy (51.5% by weight Ni-22% by weight C)
r-19.5 wt% Fe-7 wt% Mo) Comparative Example 1: As in Example 1, an Ag coating layer having a thickness of 200 ° was formed on the surface of the pearl mica pigment.

Example 8: In the same manner as in Example 1, as shown in Table 2, a transparent glass flake (average particle size: 300 μm, average thickness: 20 μm, manufactured by Barotini Co.) was coated on the surface with a film thickness of 2 μm.
A coating layer of SUS304 alloy (74 wt% Fe-18 wt Cr-8 wt% Ni) was formed. Examples 9 to 14: In the same manner as in Example 1, the following iron-based and Ni-based alloy coating layers were formed on the surface of the same transparent glass flake as shown in Table 2. SUS309S alloy (66 wt% Fe-22 wt% Cr
-12% by weight Ni) SUS310S alloy (55% by weight Fe-25% by weight Cr)
-20% by weight Ni) SUS316 alloy (67.5% by weight Fe-18% by weight C)
r-12 wt% Ni-2.5 wt% Mo Hastelloy B alloy (67 wt% Ni-28 wt% Mo-
Hastelloy C alloy (58% Ni-22% Cr-
13% by weight Mo-4% by weight Fe-3% by weight W) Hastelloy G alloy (51.5% by weight Ni-22% by weight C)
(r-19.5% by weight Fe-7% by weight Mo) Comparative Example 2: As in Example 1, an Ag coating layer having a thickness of 200 ° was formed on the surface of the transparent glass flake.

Using the samples obtained in Examples 1 to 14 and Comparative Examples 1 and 2, coated plates were prepared under the following conditions.
8 parts by weight of toluene was added to 10 parts by weight of the sample and stirred, and the sample was uniformly dispersed in toluene. To the obtained dispersion, 60 parts by weight of a thermosetting acrylic resin varnish (Almatex 448-O manufactured by Mitsui Toatsu Chemicals, Inc.) and a melamine resin varnish (Uban 20N-6 manufactured by Mitsui Toatsu Chemicals, Inc.)
0) 12 parts by weight and 15 parts by weight of a solvent (a mixed solvent of 65% toluene and 35% n-butanol) were added, and the mixture was stirred with a disper for 30 minutes to prepare a coating material. A polished steel plate having a thickness of 0.8 mm was cut into a width of 300 mm and a length of 500 mm to obtain a coating original plate. After pre-treating the coating base plate using a zinc phosphate treatment liquid (Granodine SD5000 manufactured by Nippon Paint Co., Ltd.), electrodeposition coating was performed using a cationic electrodeposition paint (Powertop U-30 manufactured by Nippon Paint Co., Ltd.) 1
Heating was performed at 60 ° C. for 30 minutes to form an undercoat film having a dry film thickness of 20 μm. Then, an intermediate coating (Nippon Paint Co., Ltd. Olga P-2 Gray) was applied, and at 140 ° C., 3
Heating was performed for 0 minutes to form an intermediate coating film having a dry film thickness of 30 μm.

Each of the undercoated base plates was metallic-coated under the following conditions. The paint prepared as described above was diluted with a paint thinner (Nippe 298, manufactured by Nippon Paint Co., Ltd.) so that the viscosity (20 ° C.) was 15 seconds with a No. 4 Ford cup. The diluted paint was electrostatically spray-coated on the intermediate coat with a spray gun so as to have a dry film thickness of 15 μm. Next, wet-on-wet clear paint (Nippon Paint Co., Ltd.)
Paint super rack 128M-1)
Heating was performed for 0 minutes to form a coating film having a total dried film thickness of 140 μm.

The glitter and weather resistance of each of the obtained coated plates were investigated by the following methods. Regarding the glitter, a 60-degree specular reflectance was measured using a digital variable-angle gloss meter (UGV-5K manufactured by Suga Test Instruments Co., Ltd.). For weather resistance,
Investigated in a 1000 hour QUV test. In the QUV test, after turning on the ultraviolet lamp at about 60 ° C for 4 hours, non-lighting for 4 hours with moisture or moisture condensation is regarded as one cycle,
This is a test method in which this cycle is repeated three times in 24 hours. The coated plate was exposed to the QUV test, periodically removed from the tester, and the change in appearance was measured with a color difference meter and a digital variable gloss meter. The amount of change before and after the test was determined as the color difference ΔE and the gloss retention%. Tables 1 and 2 collectively show the results of the investigation regarding the glitter and weather resistance. As is clear from Tables 1 and 2, in the coated plate using the metallic pigment of the present invention, the appearance change after the QUV test is extremely small, and excellent glitter and weather resistance are maintained over a long period of time. You can see that. On the other hand, in the coated plates of Comparative Examples 1 and 2, the color difference ΔE and the gloss retention were significantly reduced, and it was shown that the appearance was deteriorated by irradiation with sunlight or the like.

[0020]

[0021]

[0022]

As described above, the metallic pigment of the present invention has a coating layer of an Fe-based or Ni-based alloy on the surface of a scaly substrate such as pearl mica or glass flake. Since the coating layer of the Fe-based or Ni-based alloy has an austenitic structure with excellent weather resistance, a passivation film having high corrosion resistance is formed on the outermost surface, and the weather resistance of the metallic pigment is significantly improved. A surface that maintains excellent glitter is obtained. Further, the coating layer formed by the sputtering method has high adhesion to the flaky substrate,
Since the scaly substrate can be uniformly coated even with a small film thickness, a high-performance metallic pigment can be obtained with a small coating amount. This metallic pigment can be used for reflective tapes, display materials, signboards, road signs, etc. by mixing it with printing ink in addition to its use as a metallic paint. It can also be applied as an inhibitor.

[Brief description of the drawings]

FIG. 1 shows an apparatus for forming an Fe-based or Ni-based alloy coating layer on a scaly substrate by sputtering.

[Explanation of symbols]

1: rotating drum 2: roll 3: motor
4: Sputtering source 5: Pearl mica or glass flake 6: Heating coil 7: Decompression processing chamber 8: Valve 9: Supply pipe 10: Gas introduction pipe 1
1: branch pipe 12: fluid jet mill 13: circulation pipe 14: valve 15: valve 16: solid-gas separation device

Claims (5)

[Claims] 1. A scaly substrate and an Fe-based alloy or Ni having an austenite structure covering the surface of the scaly substrate
Excellent weather resistance metallic pigment consisting of a coating layer of a base alloy. 2. The scaly substrate according to claim 1, wherein said scaly substrate has an average particle size of 1.
A metallic pigment excellent in weather resistance, which is pearl mica or glass flake having a thickness of 0 μm to 300 μm and an average thickness of 0.1 μm to 20 μm. 3. A metallic pigment excellent in weather resistance, wherein the coating layer according to claim 1 is austenitic stainless steel. 4. A metallic pigment excellent in weather resistance, wherein the coating layer according to claim 1 is an alloy containing 50% by weight or more of Ni. 5. The coating layer according to claim 1, which has a thickness of 50 to 30.
A metallic pigment excellent in weather resistance which is formed by sputtering at 0 °.