JP4345103B2 - Metallic coating composition, coating film forming method and coating film - Google Patents

Description

  The present invention relates to a metallic paint composition, a coating method using the paint, and a coated article. More specifically, the present invention relates to a method for obtaining a glittering coating film having excellent particle feeling, luminance feeling, flip-flop property and hiding property by selectively using an aluminum flake pigment used for a base coat paint.

Various methods for forming a coating film excellent in particle feeling, brightness feeling, flip-flop property and concealing property using a metallic base coat paint and a clear paint have been tried.
Here, the meaning of the words expressing the appearance of the coating film used in the present invention will be described. “Particle feeling” means that when light is applied to a coating film, each particle of the aluminum flake pigment is reflected by the light and emits a sparkling particle. “Luminous sensation” refers to a lustrous metallic luster. Generally, the larger the particle, the stronger the radiance, the higher the “particle sensation” and the higher the “brightness”. “Flip-flop” refers to a metallic luster with directionality that varies in brightness depending on the viewing angle, with brighter highlights being preferred and darker shades being preferred. “Concealment” refers to the degree of influence of the substrate, and the smaller the influence of the substrate, the better.

As a method of obtaining a coating film appearance excellent in glitter, (A) 100 solid parts by weight of a coating film forming resin, and (B) an average particle diameter D ₅₀
A coating composition containing 0.1 to 30 parts by weight of an aluminum flake pigment having a particle diameter of 20 ± 5 μm, an average particle thickness of 0.5 to 1 μm, and a gradient n in the rosin-Rammler diagram of 2.7 or more. A coating film forming method characterized by top-coating and curing at the same time is known (Patent Document 1: Claims 1 and 2) However, this method is excellent in uniform and dense metallic luster. A coating film can be obtained, and although there are particle feeling, brightness feeling and flip-flop property, there is a drawback that the concealing property is insufficient.
JP-A-8-170034

  In addition, as a method for obtaining an aluminum-like metallic luster having excellent flip-flop properties, a method for forming a multilayer coating film in which a base coat paint (A), a metallic paint (B), and a clear paint (C) are sequentially applied, comprising: A color pigment is used for (A) and the brightness (brightness) of the coating film is set to 0 to 40 in terms of L value, and the thickness is 0.01 to 0.2 μm as the metallic pigment in the metallic paint (B). A method for forming a multilayer coating film characterized by using aluminum flakes having a ratio of 100 to 300 and having a solid content of 400 parts by weight or less of the resin composition per 100 parts by weight of the aluminum flakes is known. However, in this method, at least three coats of base coat, metallic (base coat) and clear are used in this method. There are disadvantages that the cost and productivity are inferior to those of the two coats comprising a base coat and a clear layer.

JP 2000-084483 A

Moreover, it has a coherent property and expresses a deep polychromaticity due to coloring, and a glittering coating film having a design that expresses a high saturation feeling in a highlight portion and a glittering feeling and a high saturation feeling in a shade portion is obtained. As a method, an aluminum flake pigment (1) coated with a vehicle and a metal oxide composite comprising two or more metal elements, and a glittering paint composition containing an aluminum flake pigment (2) other than the above (1) are used. However, in this method, the coating film is colored and a simple silver color is obtained by using an oxide complex composed of a coloring metal element. Not suitable for. Moreover, although it is excellent in radiance, there is a drawback that the concealing property and the flip-flop property are insufficient.
JP 2002-121492 A

In addition, as a method for preventing unevenness in the glitter feeling of the coating film formed by uniforming the orientation of the large particle size glitter material on the surface of the coating film, the first stage for forming the glittering base coating film has an average particle diameter. A coating film forming method using a large particle size scaly glitter material having an average particle diameter of 15 μm or more is known as the second stage for forming a glittering base coating film using a small particle scaly glitter material having a particle size of 10 μm or less. (See Patent Document 4: Claims 1 and 2). However, this method is also a three-coat specification including a first stage glitter base, a second stage glitter base, and a clear, as in Patent Document 2, compared to two coats consisting of a base coat and a clear layer. There is a disadvantage that the cost and productivity are inferior. Further, the average particle diameter of the glitter base of the second stage is larger than the average particle diameter of the glitter base of the first stage, and it is difficult to obtain a stable brightness feeling.
JP 2002-102798 A

Further, a fine metal foil (A) having a thickness of 0.08 μm or less and an average particle diameter of 5 to 40 μm, and a non-leafing type having a thickness of 0.1 to 1 μm and an average particle diameter of 1 to 60 μm There is known a coating composition capable of obtaining a coating film having a plating-like appearance, characterized by containing aluminum flakes (B) in a ratio of 1: 0.05 to 1:20 by weight. (Patent Document 5: Refer to Claim 1) However, although this method can obtain a coating film having a metallic appearance, there is a drawback in that the glittering particle feeling of the aluminum flake pigment cannot be obtained.
JP2000-219830

  It is considered very difficult to obtain a metallic coating film that satisfies all of the particle feeling, brightness, flip-flop property, and concealment property in the metallic coating film. The base coat is divided into the first base coat and the second base coat. A three-coating method has been devised.

  An object of the present invention is to obtain a metallic coating film satisfying all of the particle feeling, glitter feeling, flip-flop property and concealing property by a highly productive wet-on-wet 2-coat 1-bake coating method.

That is, the present invention
(A) an average particle diameter _{D 50} of more than 13 .mu.m, 25 [mu] m or less, average 0.4μm or more thickness, 2.5 [mu] m or less aluminum flake pigment (B) the average particle diameter _{D 50} of 4μm or more, 20 [mu] m or less, the average An aluminum flake pigment having a thickness of 0.1 μm or more and less than 0.4 μm;
The solid content mass ratio ((A) / (B)) of the pigment (A) to the pigment (B) is 90/10 to 10/90, and the pigment (A) is 100 mass parts of the metallic paint resin solid content. The total value ((A) + (B)) of the solid content mass of the pigment and the pigment (B) is 5 to 30 parts by mass, and this relates to a metallic coating composition.

The present invention also provides a method for forming a coating film in which the above-described metallic paint is applied, and then the clear paint is applied and cured by wet-on-wet.
Furthermore, this invention provides the coated article obtained by said method by said coating material.

  The coating composition of the present invention has a metallic coating appearance excellent in all of particle feeling, glitter feeling, flip-flop property, and concealment property by a highly productive, low-cost wet-on-wet 2-coat 1-bake coating method. Obtainable.

  In the metallic paint composition and the coating film forming method of the present invention, a metallic base coat paint and a clear paint containing two kinds of aluminum flake pigments are sequentially applied on a substrate by wet-on-wet to form a paint film. .

  The metallic base coat paint used in the method of the present invention is a liquid paint containing a film-forming base resin, a scaly glitter pigment, a solvent, an additive, and a crosslinking agent added as necessary. Examples of the base resin include acrylic resins having a crosslinkable functional group such as hydroxyl group, carboxyl group, silanol group, and epoxy group, polyester resin, alkyd resin, fluororesin, urethane resin, silicone-containing resin, and cellulose resin. Can be mentioned. These base resins can be used individually by 1 type, or can also be used in combination of 2 or more type.

  Examples of the additive include an ultraviolet absorber, a hindered amine light stabilizer, an antioxidant, a rheology control agent, and a surface conditioner. By adding an ultraviolet absorber, a hindered amine light stabilizer, an antioxidant, etc., the weather resistance of the coating film can be improved. By adding a rheology control agent, the coating workability and the coating film appearance can be improved. By adding the surface conditioner, the appearance of the coating film can be improved.

  Examples of the crosslinking agent include melamine resin, polyisocyanate compound or block polyisocyanate compound, epoxy resin or epoxy compound, carboxyl group-containing resin or compound, acid anhydride, alkoxysilane group-containing resin or compound, and the like. These crosslinking agents can be used alone or in combination of two or more.

Aluminum flake pigment of metallic base coating composition used in the present invention the method is (A) an average particle diameter _{D 50} of more than 13 .mu.m, 25 [mu] m or less, an average thickness of 0.4μm or more, 2.5 [mu] m or less of aluminum flake pigment (B) Mean particle diameter _{D 50} of 4μm or more and 20 [mu] m or less, an average thickness of 0.1μm or more, and also contains an aluminum flake pigment of less than 0.4 .mu.m,
In the solid content mass ratio of the aluminum flake pigment, A / B is 90/10 to 10/90, and (A + B) is 5 to 30 parts by mass with respect to 100 parts by mass of the resin solids.

The properties of each particle described in the present invention can be determined by the following measuring method.
The average particle diameter D ₅₀ indicates the 50% value of the particle size distribution measured by laser diffraction particle size distribution measuring apparatus. The average particle thickness (μm) is a value determined by the formula [4000 / water surface coverage (cm ² / g)], and the measurement method is, for example, “Aluminum Handbook” (9th edition, issued on April 15, 1972). , Association of Light Metals; Asakura Shoten), page 1243.

(A) an average particle diameter _{D 50} of more than 13 .mu.m, 25 [mu] m or less, average 0.4μm or more thickness, 2.5 [mu] m or less of the aluminum flake pigment, to give graininess to the coating film, the brightness sensation, the flip-flop property However, it has the feature of being inferior in concealment. Examples of commercially available aluminum pigments include “Alpaste 56-501”, “Alpaste TCR-3040”, and “Alpaste 51-148B” manufactured by Toyo Aluminum Co., Ltd.

Aluminum flake pigment (A) has an average particle diameter _{D 50.} 13 to 25 [mu] m, an average thickness of 0.4～2.5Myuemu. When the average particle diameter D ₅₀ exceeds 25 μm and / or the average thickness exceeds 2.5 μm, the appearance of the coating film is deteriorated. Preferably, the average thickness of (A) is 2.0 μm or less, and particularly preferably the average thickness is 1.5 μm or less.

(B) the average particle diameter _{D 50} of 4μm or more and 20 [mu] m or less, an average thickness of 0.1μm or more, the aluminum flake pigment of less than 0.4μm is in the coating film, the flip-flop property, the particles and brightness sensation increases There is a feature that concealment can be given to the extent that it is not impaired. Examples of commercially available aluminum pigments include “Alpaste 6340NS” manufactured by Toyo Aluminum Co., Ltd. and “SAP 550N” manufactured by Showa Aluminum Co., Ltd.

Aluminum flake pigment (B) has an average particle diameter _{D 50.} 4 to 20 [mu] m, a mean thickness of less than 0.1 to 0.4 [mu] m. If this average particle diameter D ₅₀ is more than 20 [mu] m, the poor hiding properties of the paint film.
In addition, when the average thickness of the pigment (B) is less than 0.1 μm, it is not possible to obtain a sparkling particle feeling. From this viewpoint, it is more preferable that the average thickness of the pigment (B) is 0.15 μm or more. Further, the average thickness of the pigment (B) is less than 4.0 μm, more preferably 0.38 μm or less, and further preferably 0.35 μm or less.

  The mass ratio (A / B) of the aluminum flake pigment (A) and the aluminum flake pigment (B) is 10/90 to 90/10. When (A / B) is larger than 90/10, the concealability is insufficient and the substrate is easily affected by the substrate, and a stable silver color cannot be obtained. When (A / B) is smaller than 10/90, the brightness is insufficient, the metallic luster is poor, and the flip-flop property is also lowered. From this viewpoint, (A / B) is preferably 10/90 to 80/20, and more preferably 10/90 to 70/30.

Further, the total amount of the aluminum flake pigment (A) (B), based on resin solids 100 parts by weight and 5-30 parts by weight. When the total amount of the aluminum flake pigments (A) and (B) is less than 5 parts by mass, the concealability is insufficient, and when it exceeds 30 parts by mass, the appearance is deteriorated.

In the present invention, a mica pigment can be used as necessary. The shape and type of the mica pigment are not particularly limited, and examples thereof include white mica pigment, interference mica pigment, and colored mica pigment. Mica pigments in which the surface of mica powder is coated with metal oxides such as TiO ₂ , SnO ₂ , ZrO ₂ , Fe ₂ O ₃ , ZnO ₂ , Cr ₂ O ₃ , CoO, V ₂ O ₅ , and their hydrates. Can be suitably used because it is excellent in glitter and pearl. As a commercial product of white mica pigment, for example, “Iriodin 103WNT” manufactured by Merck Japan Co., Ltd., and as a commercial product of interference mica pigment, for example, “Iriodin 225WNT” manufactured by Merck Japan Co., Ltd. Examples of the commercially available products include “Iriodin 504WII” and “Iriodin New GP Blue Green WNT” manufactured by Merck Japan Co., Ltd.

  In the method of the present invention, the method for applying the metallic base coat paint is not particularly limited, and for example, it can be applied by air spray coating, airless spray coating, low-pressure atomizing spray coating (HVLP), electrostatic coating, or the like. Although there is no restriction | limiting in particular in the thickness of a coating film, It is preferable that the cured coating film thickness is 5-20 micrometers.

  The clear coating used in the method of the present invention is a coating that forms a colorless transparent or colored transparent coating film. By sequentially applying the metallic base coat paint and the clear paint by wet on wet, the design properties, finished appearance, weather resistance, chemical resistance, water resistance, moisture resistance and the like of the coating film can be further improved. There are no particular restrictions on the clear coating used, for example, acrylic resins, polyester resins, alkyd resins, fluororesins, urethane resins, silicone-containing resins having crosslinkable functional groups such as hydroxyl groups, carboxyl groups, silanol groups, and epoxy groups. Thermosetting comprising a base resin and a crosslinking agent such as melamine resin, polyisocyanate compound or block polyisocyanate compound, epoxy resin or epoxy compound, carboxyl group-containing resin or compound, acid anhydride, alkoxysilane group-containing resin or compound The organic solvent type coating material which has a resin composition, a solvent, various additives, etc. as a component can be mentioned.

  In the method of the present invention, the clear coating method is not particularly limited, and for example, it can be applied by air spray coating, airless spray coating, electrostatic coating or the like. Although there is no restriction | limiting in particular also in the thickness of a coating film, It is preferable that cured coating film thickness is 10-50 micrometers.

  In the method of the present invention, the metallic base coat paint and the clear paint are sequentially applied by wet on wet. That is, if necessary, a metallic base coat paint is applied onto a substrate on which an undercoat film or an intermediate coat film has been formed, and a clear paint is applied before the metallic base coat paint is sufficiently dried. Crosslink and cure the paint and clear paint. By applying wet-on-wet, energy can be saved, the coating process can be simplified, and the cost for forming the glitter coating can be reduced.

  After coating by wet-on-wet, it is possible to cure by crosslinking in the range from room temperature to 180 ° C. From room temperature to 100 ° C., the use of a two-component urethane paint is preferred, and at 100 ° C. to 180 ° C., for example, the use of a one-pack type acrylic melamine resin is preferred, but it is not particularly limited thereto.

  When the material such as plastic having low heat resistance or the intermediate coating is a two-component urethane coating, the curing temperature is more preferably 70 to 120 ° C. In addition, when the material such as a metal having high heat resistance or the intermediate coating is a one-component melamine coating, the curing temperature is more preferably 120 to 160 ° C. The curing time varies depending on the curing temperature, and 10 to 50 minutes is appropriate at a curing temperature of 70 to 120 ° C, and 10 to 40 minutes is appropriate at a curing temperature of 120 to 160 ° C.

  There is no particular limitation on the substrate on which the metallic coating film is formed by the method of the present invention, and for example, it can be applied to various substrates such as wood, metal, glass, cloth, plastic products, plastic foams, The present invention can be particularly suitably applied to a metal product capable of cationic electrodeposition. Examples of plastic products include molded products such as polypropylene, ABS, polyester, nylon, and the like. Specifically, automobile parts such as passenger cars, trucks, motorcycles, buses, personal computers, mobile phones, etc. An industrial product etc. can be mentioned. Examples of metal products that can be cationically electrodeposited include iron, copper, aluminum, tin, zinc, and the like, and alloys containing these metals. Specifically, such as passenger cars, trucks, motorcycles, buses, etc. Car bodies can be mentioned.

  In the method for forming a metallic coating film of the present invention, an undercoating film or an intermediate coating film can be formed on a substrate. As a method for forming the undercoat film, it is preferable to apply a cationic electrodeposition paint having excellent anticorrosive properties as the undercoat film after chemical conversion treatment with phosphate, chromate or the like on the metal substrate. In addition, an undercoating material can be applied to the plastic substrate as necessary. For example, it is preferable to apply a chlorinated polyolefin resin-based paint or the like to a low-polarity base material such as a polypropylene base material.

  In the method of the present invention, by forming an intermediate coating film on the substrate, the underlying defects are concealed, the surface smoothness after the top coating is secured, the appearance is improved, and the impact resistance and chipping resistance are increased. The coating film performance such as can be imparted. The intermediate coating used for forming the intermediate coating film can be composed of organic or inorganic color pigments, extender pigments, and the like, and a film-forming thermosetting resin, a solvent, a crosslinking agent, and the like.

  There is no restriction | limiting in particular in the coating-film formation thermosetting resin used for intermediate coating, For example, an acrylic resin, a polyester resin, an alkyd resin, an epoxy resin, a urethane resin etc. can be mentioned. Moreover, as a crosslinking agent, a melamine resin, a polyisocyanate compound, a block polyisocyanate compound etc. can be mentioned, for example.

  It is also possible to apply the metallic base coat paint in an uncured state after applying the intermediate paint on the base material that has been primed. In order to cure the intermediate coating, it is preferable to heat to a curing temperature of 60 to 180 ° C. If the curing temperature is less than 60 ° C, curing may not proceed sufficiently. When the curing temperature exceeds 180 ° C., the coating film may be deteriorated in physical properties such as yellowing of the coating film and becoming hard and brittle. When the material such as plastic with low heat resistance or the intermediate coating is a two-component urethane paint, it can be cured from room temperature to 180 ° C., but the curing temperature should be 70 to 120 ° C. More preferred. In addition, when the material such as a metal having high heat resistance or the intermediate coating is a one-component melamine coating, the curing temperature is more preferably 120 to 160 ° C. The curing time varies depending on the curing temperature, and 10 to 50 minutes is appropriate at a curing temperature of 70 to 120 ° C, and 10 to 40 minutes is appropriate at a curing temperature of 120 to 160 ° C.

  Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

In Examples and Comparative Examples, evaluation was performed by the following method.
(1) Particle Feeling Evaluate the degree to which glittering aluminum flake pigments are radiated by light irradiation of the test plate with the naked eye.
3- The above-mentioned particle-like brightness was clearly expressed.
2- The above-mentioned granular shine was almost expressed.
1—The above-mentioned particle brightness is insufficient.
(2) Luminance sensation From the highlight position of the test plate, the degree of appearance of a design with a high glossy metallic luster is visually evaluated.
3- The above design was clearly expressed.
2- The above design was almost developed.
1- The design is not sufficiently developed.
(3) Flip-flop property The degree of high change is visually evaluated from the highlight and shade positions of the test plate.
3- Expressed a clear change.
2- The change was almost expressed.
1—Insufficient expression of change.
(4) Concealment property Using a tin plate as a base material, a concealment rate test paper conforming to JIS K5600-4-1 4.1.2 Method B (Concealment rate test paper) is placed, and the base coat paint is continuously sprayed. After coating and baking so as to change the film thickness, the film thickness of the tin plate at the same site where the transparency of the white background and the black background of the concealment rate test paper was not known was measured to obtain the concealment film thickness. For the film thickness measurement, Deltascope MP30 manufactured by Fisher Instruments Co., Ltd. was used. In addition, as for the concealment film thickness, if it is 20 μm or less, it meets the object of the present invention, but it is more preferable as the concealment film thickness becomes smaller.
(5) Appearance of coating film 3-No problem.
2- No problem in practical use.
1- Inhalation or ticking is easily seen.

Example 1
Acrylic resin “LB-9020” (manufactured by NOF BASF Coatings Co., Ltd., 35% by mass of heating residue, hydroxyl value 56 mgKOH / g), rheology control agent “LC-0988” (NOF BASF coating Made by Su Co., Ltd., inorganic, heating residue 10% by mass) 3.5 parts by weight, aluminum flake pigment (A), Toyo Aluminum Co., Ltd. “Alpaste TCR3040” (heating residue 80% by mass, average Particle size (D ₅₀ ) 17 μm, average thickness 0.8 μm 1.75 parts by mass, aluminum flake pigment (B), “Alpaste 6340NS” manufactured by Toyo Aluminum Co., Ltd. (heating residue 71%, average particle size (D ₅₀ ) 13 μm, average thickness 0.29 μm) 7.89 parts by mass, melamine resin “Uban 122” (Mitsui Chemicals, Inc. butylated melamine) Resin, heating residue 60% by mass) 14 parts by mass, surface modifier “Modaflow” (manufactured by Monsanto Co., Ltd., acrylic copolymer, heating residue 100% by mass) 0.2 parts by mass, xylene 10 parts by mass and acetic acid 27.03 parts by mass of butyl was mixed and stirred with a disper for 10 minutes to make uniform, thereby preparing a metallic base coat paint.

  Next, on the tin plate degreased with isopropyl alcohol, a polyester one-component melamine paint “HIEIPICO No.500 intermediate coat” (manufactured by NOF BASF Coatings Co., Ltd.) is used as the intermediate coat. Air spray coating was carried out to set, and after setting for 10 minutes, it was cured by heating at 140 ° C. for 20 minutes to prepare an intermediate coating plate.

  On the intermediate coating plate, the viscosity was adjusted with a diluted thinner (butyl acetate / xylene = 70/30 (mass ratio)) so that the viscosity of the coating was 12 seconds at “Ford Cup # 4” (25 ° C.). The metallic base coat paint was air-sprayed so that the dry film thickness was 20 μm and flashed off for 1 minute. In addition, an acrylic one-component melamine paint “BELCOAT No6200 Clear” (manufactured by NOF BASF Coatings Co., Ltd.) as a clear paint is wet-on-wet and air spray painted so that the dry coating thickness is 30 μm. went. Then, after leaving it indoors for 10 minutes, it heat-dried at 140 degreeC for 20 minutes, and observation evaluation was performed 24 hours afterward. The evaluation results are shown in Table 1.

(Examples 2 to 5, Reference Examples 1 to 5 )
In the same manner as in Example 1, a metallic base coat was prepared with the coating composition shown in Tables 1 and 2, and a test plate was prepared and evaluated in the same manner as in Example 1. The evaluation results are shown in Tables 1 and 2.

(Example 6 )
Acrylic resin “LB-9020” (manufactured by NOF BASF CO., LTD., Heating residue 55% by mass, hydroxyl value 56 mgKOH / g) 42.74 parts by mass, rheology control agent “LC-0988” (NIPPON FATS BASF COATING Made by Su Co., Ltd., inorganic, heating residue 10% by mass) 3.5 parts by weight, aluminum flake pigment (A), Toyo Aluminum Co., Ltd. “Alpaste TCR3040” (heating residue 80% by mass, average Particle size (D ₅₀ ) 17 μm, average thickness 0.8 μm 1.75 parts by mass, aluminum flake pigment (B), “Alpaste 6340NS” manufactured by Toyo Aluminum Co., Ltd. (heating residue 71%, average particle size (D ₅₀ ) 13 μm, average thickness 0.29 μm)
7.89 parts by mass, “Sumijour N75” (manufactured by Sumitomo Bayer Urethane Co., Ltd., polyisocyanate resin, nonvolatile content = 75%, isocyanate content = 16.5%), 5.99 parts by mass as polyisocyanate resin Surface modifier “Modaflow” (manufactured by Monsanto Co., Ltd., acrylic copolymer, 100% by mass of heating residue) 0.2 parts by mass, xylene 10 parts by mass and butyl acetate 27.93 parts by mass were mixed with a disper 2 A metallic base coat paint was prepared by stirring for a minute to make it uniform.

  Next, dilute thinner (butyl acetate / xylene = 70/30 (mass) so that the coating viscosity becomes 11 seconds at “Ford Cup # 4” (25 ° C.) on the intermediate coating plate prepared in the same manner as in Example 1. Ratio)), the above-mentioned metallic base coat paint whose viscosity was adjusted was air-sprayed so that the dry film thickness was 20 μm and flashed off for 1 minute. Further, a two-component polyurethane paint “High Urethane No 6500 Clear” (manufactured by NOF BASF Coatings Co., Ltd.) was applied as a clear paint by air spray coating so that the dry coating thickness was 30 μm by wet on wet. Thereafter, the samples were left in the room for 3 days for evaluation, and the evaluation results are shown in Table 2.

(Comparative Examples 1 to 4)
In the same manner as in Example 1, a metallic base coat paint was prepared with the paint composition shown in Table 3, and a test plate was prepared and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 3.

In Tables 1 to 3, each product number of the pigment indicates the following: (1) Product name “Alpaste TCR-3040” manufactured by Toyo Aluminum Co., Ltd., 80% heat residue, average particle size D ₅₀
17 μm, average thickness 0.8 μm
(2) Product name “Alpaste 56-501” manufactured by Toyo Aluminum Co., Ltd., 70% heat residue, average particle size D ₅₀ 28 μm, average thickness 1.0 μm
(3) Product name “Alpaste 51-148B” manufactured by Toyo Aluminum Co., Ltd., 65% heat residue, average particle size D ₅₀ 37 μm, average thickness 0.62 μm
(4) Product name “Alpaste 6340NS” manufactured by Toyo Aluminum Co., Ltd., 71% heat residue, average particle size D ₅₀ 13 μm, average thickness 0.29 μm
(5) Product name “SAP 550N” manufactured by Showa Aluminum Powder Co., Ltd., heating residue 66%, average particle diameter D ₅₀ 21 μm, average thickness 0.24 μm
(6) Product name “Metalure”
Made by AVERY DENNISON, heating residue 10%, average particle size D ₅₀ 13 μm, average thickness 0.05 μm

  In Examples 1-4, the case where the ratio of the aluminum pigment (A) and the aluminum pigment (B) was changed was shown. In all cases, a coating film excellent in glittering particle feeling, brightness feeling, flip-flop property, coating film appearance property and concealing property is obtained. Among Examples 1 to 4, particularly excellent results were obtained in Examples 1 and 2. In Example 3, A / B is 75/25, but the concealing film thickness is slightly larger. In Example 4, A / B is 85/15, but the concealment film thickness is slightly increased.

Example 5 and Reference Examples 1 and 2 are cases in which the ratio of the resin solid content to the total amount of the aluminum pigment (A) and the aluminum pigment (B) was changed. In Example 5, the (A + B) / resin solid content ratio was 15/100, but a coating film excellent in brightness, flip-flop property, coating film appearance property and concealing property was obtained. In Reference Example 1 , the (A + B) / resin solid content ratio was 35/100, but the coating film appearance deteriorated in place of the concealed film thickness becoming smaller. In Reference Example 2 , the ratio of (A + B) / resin solid content was 45/100, but the appearance of the coating film was lowered instead of the concealed film thickness being further reduced.

In Reference Examples 3 and 4 , the average particle diameter D ₅₀ and the average thickness of the aluminum pigment (A) were changed. In Reference Example 3, but the average particle diameter D ₅₀ of the pigment (A) was 28 .mu.m, the coating appearance is lowered as compared with Examples 1 and 2. In Reference Example 4, but the average particle diameter D ₅₀ of the pigment (A) was significantly 37μm slightly, coating film appearance may be lowered as compared with Examples 1 and 2, hiding film thickness became slightly thicker.

In Reference Example 5, although the average particle diameter D ₅₀ of the aluminum pigment (B) was slightly increased to 21 [mu] m, the coating appearance is slightly reduced as compared with Examples 1 and 2, hiding film thickness becomes thicker. Example 6 is a case where the paint type is changed to an acrylic urethane paint. Also in this case, a coating film excellent in brightness, flip-flop property, coating film appearance property and concealing property is obtained.

However, as shown in Table 3, in Comparative Example 1 in which the amount of the aluminum pigment (A) is small (A / B ratio is 5/95), the glitter and flip-flop properties are insufficient. In Comparative Example 2 where the amount of the aluminum pigment (B) is large (A / B ratio is 95/5), the concealment film thickness is greatly increased to 26 μm.
In Comparative Example 3, the aluminum pigment (A + B) was less than the resin solid content, that is, (A + B) / resin solid content = 3/100. In Comparative Example 3, the concealment property is remarkably reduced, and the brightness and flip-flop properties are also affected by the influence of the substrate. In Comparative Example 4, the aluminum pigment (A + B) was increased with respect to the resin solid content, that is, (A + B) / resin solid content = 60/100. In Comparative Example 4, the appearance of the coating film was significantly reduced. Although the comparative example 5 is a case where the aluminum foil which made average thickness less than 0.1 micrometer is used as an aluminum pigment (B), it becomes a metallic tone and a particle feeling is not obtained.

As described above, according to the present invention, the metallic base coating composition is coated with wet-on-wet two-coat one-bake coating so that the appearance of a metallic coating film excellent in particle feeling, glitter feeling, flip-flop property, and concealment property can be achieved. Can be obtained by an inexpensive method.

Claims (3)

A metallic paint composition comprising:
(A) an average particle diameter _{D 50} of more than 13 .mu.m, 25 [mu] m or less, average 0.4μm or more thickness, 2.5 [mu] m or less aluminum flake pigment, and (B) the average particle diameter _{D 50} of 4μm or more, 20 [mu] m or less An aluminum flake pigment having an average thickness of 0.1 μm or more and less than 0.4 μm,
The solid content mass ratio ((A) / (B)) of the pigment (A) to the pigment (B) is 90/10 to 10/90, and the pigment (A ) And the pigment (B) are 5 to 30 parts by mass of the total solid content ((A) + (B)), and the metallic paint composition.   The metallic paint according to claim 1 is applied onto a substrate, and then a clear paint is applied onto the metallic paint composition by a wet-on-wet method, and the metallic paint composition and the clear paint are cured. A method for forming a coating film. A coating film obtained by the method according to claim 2.