JP2006192384A - Multiple layer coating film forming method and coating film structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for forming a multiple layer coating film which has an excellent weather resistance, and an excellent bright appearance of little yellow. <P>SOLUTION: In the method for forming the multiple layer coating film comprising a process of forming a colored base coating film (A), a luster base coating film (B) and a clear coating film (C) on a substrate progressively, the method for forming the multiple layer coating film in which the luster base coating film (B) comprises a luster pigment (a) and a fluorescent white pigment (b), and a coating film structure are provided. The fluorescent white pigment (b) is one or two or more kinds selected from fluorescent materials where alkaline earth metal aluminate fluorescent material is a host crystal, and europium, dysprosium or neodymium is a potentiated agent. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a method for forming a multilayer coating film excellent in weather resistance and design properties, and a coating film structure.

The purpose of applying the paint is to protect the material and impart aesthetics. In recent years, consumer demands have been diversifying, particularly in the fields of automobile skins and home appliances. In addition to conventional solid paint colors, metallic tones using bright pigments such as aluminum pigments and mica pigments are used. A lot of paint colors and pearl color have come into use.

  Among these metallic tone paint colors and pearl tone paint colors, the so-called white pearl paint color having a high whiteness is particularly popular for luxury cars. White pearl coating is usually a multi-layer coating consisting of three layers: a base coating containing a titanium dioxide pigment, a metallic base coating containing a glittering pigment with a scaly substrate coated with titanium dioxide, and a top clear coating. Consists of a membrane. Here, there is a slight yellowishness of the titanium dioxide pigment, a yellow color complementary to the interference color from the glitter pigment, a yellowish resin, etc., and this yellowness impairs the high-class feeling of the coating film. Hated.

  The use of a fluorescent brightening agent as a countermeasure against yellowing is disclosed (for example, see Patent Document 1). The fluorescent whitening agent is a kind of dye, which absorbs ultraviolet rays (wavelength around 380 nm) and converts it into visible blue visible light (wavelength around 440 nm; referred to as fluorescence) and emits it. For this reason, when it is used for a yellowish coating film, blue light is added and the effect of appearing white as if shining is achieved. However, fluorescent brighteners are generally poor in weather resistance, and there is a problem that the effect of brighteners diminishes rapidly over time, and there is concentration quenching, so the amount used is limited and sufficient effects are exhibited. Difficult to do.

  On the other hand, a fluorescent organic white pigment composition having excellent concealability is disclosed as a white pigment having a high degree of whiteness (see, for example, Patent Document 2). However, there is a problem that it is too expensive to use as a substitute for the titanium dioxide pigment used in the white base coating film, and when it is added in a large amount until the whiteness exceeds the conventional white base, the weather resistance is lowered. There is a problem of coming.

Japanese Patent Laid-Open No. 1-313575 JP-A-11-130975

The objective of this invention is providing the formation method of the multilayer coating film which is excellent in a weather resistance, and has the external appearance excellent in the glittering feeling with little yellowishness.

The present invention
1. A glittering base coating (B) and a clear coating (C) comprising a color base coating (A), a glittering pigment (a) and a fluorescent white pigment (b) are sequentially formed on a substrate. A method for forming a multilayer coating film, wherein the fluorescent white pigment (b) is a phosphor having an alkaline earth metal aluminate phosphor as a base crystal and europium, desprosium or neodymium as an activator. A multilayer coating film forming method, characterized in that it is one or more selected from among the above,
2. Item 1. The glittering base coating film (B) comprises two layers of a coating film (B1) containing the glittering pigment (a) and a coating film (B2) containing the fluorescent white pigment (b). The multilayer coating film forming method according to the description,
3. The glitter pigment (a) is obtained by coating a scaly substrate with titanium dioxide, and the scaly substrate is one of mica, glass flakes, artificial mica, silica flakes, and alumina flakes. The method for forming a multilayer coating film according to item 1 or 2,
4). Any one of 1 to 3 which contains a glitter pigment (a) in the range of 0.1-30 weight part with respect to 100 weight part of resin components in a glitter base coating film (B). The method for forming a multilayer coating film according to claim 1,
5. Any of 1 to 4 which contains fluorescent white pigment (b) within the range of 0.1-200 weight part with respect to 100 weight part of resin components in a glittering base coating film (B). It relates to the coating-film structure obtained by the multilayer coating-film formation method of any one of clauses 6.1-5.

The multilayer coating film obtained by using the multilayer coating film forming method of the present invention comprises a fluorescent white pigment and is compared with a general fluorescent whitening agent having an effect of increasing whiteness in the same manner. Thus, it is excellent in weather resistance and has an excellent appearance with less yellowness and brightness, and is particularly useful in fields that require a high-grade appearance such as automobile outer panels and home appliances.

In the method of the present invention, the base material is a metal such as iron, zinc, aluminum, magnesium, an alloy containing these, a molded product plated or vapor-deposited with these metals, and glass, plastic, foam, etc. A molding etc. can be mentioned. Depending on these materials, it can be appropriately degreased or surface treated to form a substrate. Furthermore, an undercoat film or an intermediate coat film can be formed on the substrate to form a substrate, and these are particularly preferable.

  The undercoat film is formed to conceal the surface of the material or impart anticorrosion and rustproofness to the material, and can be obtained by applying an undercoat paint, drying and curing. it can. The type of the undercoat paint is not particularly limited, and examples thereof include an electrodeposition paint and a solvent-type primer.

  The intermediate coating film is formed to conceal the surface of the material or the undercoating film, or to impart adhesion or chipping resistance. It can be obtained by applying a paint and drying and curing. The type of intermediate coating is not particularly limited, and known ones can be used. For example, an organic solvent-based or water-based intermediate coating containing a thermosetting resin composition and a color pigment as essential components can be preferably used. .

  In the case where an undercoat film or an intermediate coat film is formed as the substrate, the undercoat film or the intermediate coat film can be heated, and a coating material for the next step described later can be applied after crosslinking and curing. Or the coating material of the next process can also be applied in a state where the undercoat film and / or the intermediate coat film are uncured.

  The method for forming a multilayer coating film of the present invention comprises forming a colored base coating film (A), a glittering base coating film (B), and a clear coating film (C) in this order on the substrate as described above. .

  The colored base coating film (A) of the method of the present invention is usually formed from a thermosetting paint containing a base resin, a crosslinking agent and a color pigment. The thermosetting paint can be used without particular limitation, such as an organic solvent type, an aqueous type, and a powder type.

  Examples of the base resin include acrylic resins having a crosslinkable functional group such as a hydroxyl group, an epoxy group, a carboxyl group, and a silanol group, a polyester resin, and an alkyd resin.

  Examples of the crosslinking agent include amino resins such as melamine resins and urea resins, polyisocyanates, block polyisocyanates, polyepoxides, and polycarboxylic acids. The polyepoxide or polycarboxylic acid may be a polymer such as a copolymer.

  These base resin and crosslinking agent are used by dissolving or dispersing in an organic solvent and / or a solvent such as water.

  Further, as the color pigment, one or a combination of two or more conventionally known pigments can be used for ink and paint. Specific examples of color pigments include metal oxide pigments such as titanium oxide and iron oxide, composite metal oxide pigments such as titanium yellow, carbon black, azo pigments, quinacridone pigments, diketopyrrolopyrrole pigments, and perylene pigments. Perinone pigments, benzimidazolone pigments, isoindoline pigments, isoindolinone pigments, metal chelate azo pigments, phthalocyanine pigments, indanthrone pigments, dioxane pigments, indigo pigments, and the like. . In particular, it is preferable to use a combination of titanium dioxide, which is a white metal oxide pigment, and a small amount of a phthalocyanine pigment or a carbon black pigment. The colored pigment is preferably in the form of fine particles having an average particle size of 1 μm or less. The blending amount of the color pigment is not particularly limited, but from the viewpoint of the hue of the coating film and the finish, usually, the total is preferably about 1 to 200 parts by weight per 100 parts by weight of the resin component including the crosslinking agent, particularly preferably, 10 to 150 parts by weight.

  If necessary, the above-mentioned thermosetting paint further includes a solvent such as water or an organic solvent, a rheology control agent, a pigment dispersant, an anti-settling agent, a curing catalyst, an antifoaming agent, an antioxidant, and an ultraviolet absorber. Various additives, extender pigments and the like can be contained.

  In the present invention, in order to sufficiently exhibit the effect of the fluorescent white pigment described later, the color of the colored base coating film (A) is preferably a pale color, and particularly those having high whiteness are suitable.

  In the method of the present invention, the glittering base coating film (B) is formed on the colored base coating film (A). The glittering base coating film is a coating film containing the glittering pigment (a) and the fluorescent white pigment (b), but the coating film (B1) containing the glittering pigment (a) and the fluorescent white pigment. It may consist of two layers of the coating film (B2) containing the pigment (b). In the case of two layers, even if the coating film (B2) is formed on the coating film (B1), the coating film (B1) is formed on the coating film (B2). May be.

  The paint used for forming the glitter base coating film (B) is preferably a thermosetting paint containing a base resin and a crosslinking agent. The thermosetting paint is not particularly limited, and the same thermosetting paint as that forming the colored base coating film (A) can be used.

  Examples of the glitter pigment (a) contained in the glitter base coating film (B) include flaky metal pigments such as aluminum, copper, nickel alloys, and stainless steel, flaky metal pigments whose surfaces are coated with metal oxides, and surfaces Scale-like metal pigments with colored pigments chemically adsorbed on, scale-like aluminum pigments with an aluminum oxide layer formed by causing an oxidation-reduction reaction on the surface, aluminum solid solution plate-like iron oxide pigments, glass flake pigments, metal surfaces Or glass flake pigment coated with metal oxide, glass flake pigment with a colored pigment chemisorbed on the surface, interference mica pigment coated with titanium dioxide on the surface, reduced mica pigment reduced by interference mica pigment, colored pigment on the surface Colored mica pigments that are chemically adsorbed or coated with iron oxide on the surface, graphite pigments that are coated with titanium dioxide on the surface, Silica flakes or alumina flake pigment coated with titanium dioxide, disk-shaped iron oxide pigments, holographic pigments, synthetic mica pigments, cholesteric liquid crystal polymer pigments having a helical structure, and the like oxy bismuth pigments chloride. Of these, those obtained by coating scaly substrates such as mica, glass flakes, artificial mica, silica flakes, and alumina flakes with titanium dioxide are preferable in order to exhibit the effect of the fluorescent white pigment (b) described later.

  In addition, the fluorescent white pigment (b) used in the present invention absorbs ultraviolet rays (wavelength around 380 nm), changes it into visible blue visible light (wavelength around 440 nm; referred to as fluorescence), and emits fluorescent whitening. A pigment having an effect, specifically, a phosphor having an alkaline earth metal aluminate phosphor as a base crystal and europium, desprosium or neodymium as an activator can be preferably used. The alkaline earth metal is not particularly limited, and examples thereof include strontium and barium.

  The fluorescent white pigment preferably has a water content of 1.0% by weight or less. The average primary particle diameter is preferably 5 μm or less at a 50% median diameter and 10 μm or less at a 90% median diameter.

  The content of the glitter pigment (a) and the fluorescent white pigment (b) is such that the glitter pigment (a) is 0.1 to 30 weights per 100 parts by weight of the resin component in the glitter base coating film (B). Parts, particularly 1 to 15 parts by weight, and that the fluorescent white pigment (b) is in the range of 0.1 to 10 parts by weight, particularly 2 to 8 parts by weight, the balance between brightness, weather resistance and whiteness Suitable from

  When the glittering base coating film (B) is composed of two layers of a coating film (B1) containing the glittering pigment (a) and a coating film (B2) containing the fluorescent white pigment (b), The glitter pigment (a) is preferably in the range of 0.1 to 30 parts by weight, particularly 1 to 15 parts by weight, based on 100 parts by weight of the resin solid content of the film (B1), and the resin solid content of the coating film (B2) The fluorescent white pigment (b) is preferably in the range of 0.1 to 200 parts by weight, particularly preferably 1 to 150 parts by weight, and more preferably 3 to 120 parts by weight with respect to 100 parts by weight.

  In particular, when the coating film (B2) containing the fluorescent white pigment (b) is formed in a lower layer than the coating film (B1) containing the glitter pigment (a), the resin solids of the coating film (B2) The fluorescent white pigment (b) is preferably in the range of 50 to 150 parts by weight per 100 parts by weight of the minute.

  In the method of the present invention, the paint used for forming the clear coating film (C) is a colorless or colored transparent comprising a resin component and a solvent as main components, and further containing other paint additives as required. It is a liquid or powder paint that forms a coating film.

  As the clear paint, a conventionally known clear paint can be used without limitation. For example, a liquid or powdery coating composition containing a base resin and a crosslinking agent can be applied. Examples of the base resin include acrylic resin, polyester resin, alkyd resin, fluororesin, urethane resin, and silicon-containing resin containing a crosslinkable functional group such as a hydroxyl group, a carboxyl group, a silanol group, and an epoxy group. It is done. As a crosslinking agent, a melamine resin capable of reacting with the functional group of the base resin, urea resin, polyisocyanate compound, block polyisocyanate compound, epoxy compound or resin, carboxyl group-containing compound or resin, acid anhydride, Examples thereof include alkoxysilane group-containing compounds or resins. Moreover, additives, such as solvents, such as water and an organic solvent, a curing catalyst, an antifoamer, and an ultraviolet absorber, can be suitably blended as needed.

  In the multilayer coating film forming method of the present invention, a colored base coating film (A), a glittering base coating film (B), and a clear coating film (C) are sequentially formed on a substrate.

  After the colored base coating (A) coating is applied on the substrate, it is baked as necessary, and the glittering base coating (B) coating is applied on the colored base coating and baked as necessary. A multilayer coating film can be obtained by coating and baking the clear coating film (C) on the glittering base coating film. Baking between the respective stages can be omitted as long as there is no coating surface abnormality such as a mixed layer or an armpit, and is appropriately selected according to the coating system, film thickness, and the like. In addition, when the glittering base coating film (B) is composed of two layers, after coating the first layer, it can be baked as necessary and then the second layer can be coated and baked as necessary. .

  Further, the coating can be usually performed using electrostatic coating, air spray, airless spray, and the like, and the baking condition is not particularly limited as long as the coating film is cured. Bake at a temperature in the range of about 180 ° C., preferably in the range of about 120-160 ° C. for a period of about 10-40 minutes.

  The appropriate thickness of each layer is 10-50 μm for the colored base coating (A), 10-50 μm for the glittering base coating (B), and 10-50 μm for the clear coating (C). When the coating film (B) is one layer, the thickness is particularly preferably about 10 to 30 μm, and when the glittering base coating film (B) is two layers, the total of the two layers is particularly preferably about 15 to 40 μm.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. Hereinafter, both “parts” and “%” are based on weight.
Preparation of base material Degreased and zinc phosphate-treated steel plate (JISG3141, size 400 × 300 × 0.8 mm) and cationic electrodeposition paint “Electron 9400HB” (trade name: manufactured by Kansai Paint Co., Ltd., epoxy resin polyamine cationic resin (Using a block polyisocyanate compound as a curing agent) is electrodeposited so as to have a film thickness of 20 μm based on the cured coating film, and heated at 170 ° C. for 20 minutes to be crosslinked and cured to be electrodeposited. A membrane was obtained.

On the obtained electrodeposition coating surface, an intermediate coating “Lugabek intermediate coating gray” (trade name: manufactured by Kansai Paint Co., Ltd., polyester resin / melamine resin type, organic solvent type) is applied by air spray. Based on the film, it was coated to a film thickness of 30 μm, heated at 140 ° C. for 30 minutes to be crosslinked and cured, and a coated plate on which an intermediate coating film was formed was used as a base material.
Preparation of paint Manufacture of paint for coloring base (Production Example 1)
In a resin composition comprising 70 parts of a hydroxyl group-containing acrylic resin and 30 parts of a butylated melamine resin, 100 parts of “CR-95” (trade name, manufactured by Ishihara Sangyo Co., Ltd., titanium dioxide pigment) are mixed and dispersed together with an organic solvent. By adjusting the viscosity to 15 seconds / Ford Cup # 4, a colored base paint having a solid content concentration of about 30% was obtained.

Production of paint for glitter base (Production Example 2)
At the time of coating, 8 parts of “Iriodin 103W2” (trade name, manufactured by Merck & Co., titanium dioxide-coated mica pigment) are mixed and dispersed together with an organic solvent in a resin composition comprising 70 parts of a hydroxyl group-containing acrylic resin and 30 parts of a butylated melamine resin. By adjusting the viscosity to 15 seconds / Ford Cup # 4, a glittering base paint TB1 having a solid content concentration of about 25% was obtained.
(Production Example 3)
At the time of coating, 8 parts of “Iriodin 225W2” (trade name, manufactured by Merck & Co., titanium dioxide-coated mica pigment) are mixed and dispersed with an organic solvent in a resin composition comprising 70 parts of a hydroxyl group-containing acrylic resin and 30 parts of a butylated melamine resin. By adjusting the viscosity to 15 seconds / Ford Cup # 4, a glittering base paint TB2 having a solid content concentration of about 25% was obtained.
(Production Example 4)
A resin composition comprising 70 parts of a hydroxyl group-containing acrylic resin and 30 parts of butylated melamine resin, 8 parts of “Iriodin 103W2” and a fluorescent white pigment (manufactured by Nemoto Special Chemical Co., Ltd., europium-activated alkaline earth aluminate phosphor, wavelength 365 nm) (Excited with near ultraviolet light, visible light near 452 nm wavelength; emitted by changing to blue) 5 parts with organic solvent are mixed and dispersed, adjusted to a viscosity of 15 seconds during coating / Ford Cup # 4, and the solid content concentration is about 25% of a glittering base paint TB3 was obtained.
(Production Example 5)
Resin composition comprising 70 parts of hydroxyl group-containing acrylic resin and 30 parts of butylated melamine resin, 8 parts of “Iriodin 225W2” and fluorescent white pigment (manufactured by Nemoto Special Chemical Co., Ltd., europium activated alkaline earth aluminate phosphor, wavelength 365 nm (Excited with near ultraviolet light, visible light near 452 nm wavelength; emitted by changing to blue) 5 parts with organic solvent are mixed and dispersed, adjusted to a viscosity of 15 seconds during coating / Ford Cup # 4, and the solid content concentration is about 25% of a glittering base paint TB4 was obtained.
(Production Example 6)
A resin composition comprising 70 parts of a hydroxyl group-containing acrylic resin and 30 parts of a butylated melamine resin is excited with a fluorescent white pigment (manufactured by Nemoto Special Chemical Co., Ltd., europium-activated alkaline earth aluminate phosphor, ultraviolet light having a wavelength of about 365 nm, Visible light near 452 nm wavelength; emitted in blue) 100 parts are mixed and dispersed with an organic solvent, adjusted to a coating viscosity of 15 seconds / Ford Cup # 4 and a solid content concentration of about 25%. TB5 was obtained.
(Production Example 7)
In Production Example 4, instead of fluorescent white pigment, “Uvitex OB” (trade name, manufactured by Ciba Specialty Chemicals, Inc., fluorescent whitening agent) was used in the same manner as in Production Example 4 except that 0.5 parts was used, and coating By adjusting the viscosity to 15 seconds per hour / Ford Cup # 4, a glittering base paint TB6 having a solid concentration of about 25% was obtained.
(Production Example 8)
In Production Example 4, production was carried out in the same manner as in Production Example 4 except that 0.5 parts of “Hostalux KS” (manufactured by Clariant, Inc., fluorescent whitening agent) was used instead of the fluorescent white pigment, and the viscosity at coating was 15 seconds / Ford By adjusting to cup # 4, a glittering base paint TB7 having a solid concentration of about 25% was obtained.
(3) Creation of multilayer coating film Example 1
The colored base paint produced in Production Example 1 is applied to the base material prepared in (1) by air spray so that the dry film thickness is 15 μm, and left at room temperature for 10 minutes, and then baked at an ambient temperature of 140 ° C. for 30 minutes. Drying was performed. The glittering base paint TB3 obtained in Production Example 4 was applied onto the obtained colored base coating film by air spray so that the dry film thickness was 15 μm, and allowed to stand at room temperature for 10 minutes. "(Acrylic / melamine resin clear paint manufactured by Kansai Paint Co., Ltd.) was applied by air spray so that the dry film thickness was 35μm, left at room temperature for 10 minutes, then baked and dried at ambient temperature of 140 ° C for 30 minutes. A multilayer coating film was obtained.

Example 2
In Example 1, a multilayer coating film was obtained in the same manner as in Example 1 except that the glitter base paint TB4 produced in Production Example 5 was used instead of the glitter base paint TB3.

Example 3
The glittering base paint TB5 obtained in Production Example 6 is applied on the colored base paint obtained in the course of the production of the multilayer paint film of Example 1 by air spray so that the dry film thickness is 15 μm. After standing at room temperature for 10 minutes, the glittering base paint TB1 obtained in Production Example 2 was applied by air spray so that the dry film thickness was 15 μm. After standing at room temperature for 10 minutes, “Majicron Clear” (Kansai) Paint (manufactured by Acrylic / Melamine resin-based clear paint) is applied by air spray so that the dry film thickness is 35 μm, left at room temperature for 10 minutes, and then baked and dried at an ambient temperature of 140 ° C. for 30 minutes. A coating film was obtained.

Example 4
In Example 3, a multilayer coating film was obtained in the same manner as in Example 3 except that the glittering base paint TB2 produced in Production Example 3 was used instead of the glittering base paint TB1.

Comparative Example 1
In Example 1, a multilayer coating film was obtained in the same manner as in Example 1 except that the glitter base paint TB1 produced in Production Example 2 was used instead of the glitter base paint TB3.

Comparative Example 2
In Example 1, a multilayer coating film was obtained in the same manner as in Example 1 except that the glitter base paint TB2 produced in Production Example 3 was used instead of the glitter base paint TB3.

Comparative Example 3
In Example 1, a multilayer coating film was obtained in the same manner as in Example 1 except that the glitter base paint TB6 produced in Production Example 7 was used instead of the glitter base paint TB3.

Comparative Example 4
In Example 1, a multilayer coating film was obtained in the same manner as in Example 1 except that the glitter base paint TB7 produced in Production Example 8 was used instead of the glitter base paint TB3.
Evaluation test About the multilayer coating film obtained by the said Example and comparative example, the coating-film performance was evaluated in accordance with the following test method. The obtained results are shown in Table 1.

Test Method Shade Whiteness: The test plate was evaluated by observing the coating film in the shade in the outdoors on a sunny afternoon.
When the shade was pale, the score was 0, and when the shade was yellow, the score was 5 in order of 0 to 5 in order of shade white.

  b * value: Using a variable angle spectrophotometer MA-68II (trade name, manufactured by X-rite), the b * value at the time of 45 ° incident 45 ° light reception was measured. The b value indicates that the smaller the numerical value, the less yellowish coloring peculiar to the pearl paint color and the whiteness.

Water resistance: The test piece was immersed in a constant temperature water bath at 40 ° C. for 10 days and taken out, and then the discoloration, swelling, etc. of the coating film were visually evaluated.
○: No abnormality such as discoloration or swelling is observed in the coating film.
X: Abnormalities such as discoloration and swelling are observed in the coating film.

Accelerated weather resistance: After an accelerated weather resistance test for 1000 hours with a super xenon weatherometer (manufactured by Suga Test Instruments Co., Ltd.), discoloration of the coating film, swelling, etc. were visually evaluated.
○: No abnormality such as discoloration or swelling is observed in the coating film.
X: Abnormalities such as discoloration and swelling are observed in the coating film.

The coating film forming method of the present invention can be applied to various industrial products, particularly to the outer plate of an automobile body.

Claims (6)

A glittering base coating (B) and a clear coating (C) comprising a color base coating (A), a glittering pigment (a) and a fluorescent white pigment (b) are sequentially formed on a substrate. A method for forming a multilayer coating film, wherein the fluorescent white pigment (b) is a phosphor having an alkaline earth metal aluminate phosphor as a base crystal and europium, desprosium or neodymium as an activator. A method for forming a multilayer coating film, comprising one or more selected from among them. The glitter base coating film (B) comprises two layers of a coating film (B1) containing the glitter pigment (a) and a coating film (B2) containing the fluorescent white pigment (b). 2. The method for forming a multilayer coating film according to 1. The glitter pigment (a) is obtained by coating a scaly substrate with titanium dioxide, and the scaly substrate is one of mica, glass flakes, artificial mica, silica flakes, and alumina flakes. The multilayer coating film forming method according to claim 1 or 2. The glitter pigment (a) is contained in a range of 0.1 to 30 parts by weight with respect to 100 parts by weight of the resin component in the glitter base coating film (B). A method for forming a multilayer coating film according to item 1. The fluorescent white pigment (b) is contained within a range of 0.1 to 200 parts by weight with respect to 100 parts by weight of the resin component in the glittering base coating film (B). The method for forming a multilayer coating film according to claim 1. The coating-film structure obtained with the multilayer coating-film formation method of any one of Claims 1-5.