JP2002126638A - Method for mending multilayer coating film, and automobile or automotive parts - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for mending a multilayer coating film by which a mended part of the coating film and the remaining part are made similar in appearance and look to each other and mending is easily carried out. SOLUTION: The method for mending a multilayer coating film obtained by forming a base coating film and a clear coating film on a substrate comprises a step for exposing a part of the base coating film to be mended by grinding and a step for coating the part to be mended (n) times (n>=2) with coating materials for mending. A coating material for i-th mending (n>=i) has a lower concentration of a pigment than a coating material for (i-1)-th mending.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for repairing a multilayer coating film, and more particularly, to a method for repairing a multilayer coating film in which a base coating film and a clear coating film are formed on a substrate such as an automobile body. The present invention also relates to a method and an automobile or automobile part having a laminated coating repaired by the above-mentioned method for repairing a laminated coating.

[0002]

2. Description of the Related Art As a top coating for automobile bodies and the like,
A paint color called “metallic” is known. Such a “metallic” coating film is generally formed from a metallic base paint containing a glittering pigment such as aluminum powder and mica powder and a clear paint, and the amount of reflected light varies depending on the viewing angle. A coating film having a high design property such as the above can be obtained.

In recent years, in order to further enhance the design of a metallic coating film, studies have been made on improving the properties of the glittering material itself. Above all, glitter pigments with even higher brightness and sharpness, such as aluminum pigments with large particle size and high flip-flop properties and mica powder with strong interference power, are adopted,
There is a demand for a coating film having high design properties by using these glitter pigments at a high concentration.

[0004] In the coating process of an automobile body or the like, if there is a coating abnormality or dust adhered to the above metallic coating, it is necessary to sharpen the necessary repair portion, apply a repair paint, and repair. Becomes Usually, the repair is performed by spray coating such as hand-blown air spray, and the repaired portion of the coating film thus repaired needs to have the same appearance as the coating film other than the repaired portion.

[0005] However, in the case of a metallic coating containing a brilliant pigment having further improved light brightness and sharpness, a ring is likely to occur in the dust portion in the coating of the repaired portion, and the repaired portion and the other portions are not. Had a problem of giving a different appearance. In order to solve this, a special repair paint is provided for each coating color, but it is not sufficient, and repair is difficult even by a skilled worker.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for repairing a laminated coating film in which the appearance and appearance of the coating film are the same between the repaired portion and the coating film other than the repaired portion, and which can be easily repaired. To provide.

[0007]

According to the present invention, there is provided a process for forming a base coating film and a clear coating film on a base material and then grinding the repair target portion of the base coating film. , A method for repairing a laminated coating film comprising a step of applying n repair paints, wherein n is 2 or more, and n ≧
The i-th repair paint, i, is a method for repairing a laminated coating film, which has a lower pigment concentration than the (i-1) -th repair paint.

The present invention is also an automobile or an automobile part having a laminated coating repaired by the above method for repairing a laminated coating. Hereinafter, the present invention will be described in more detail.

The method for repairing a laminated coating film according to the present invention comprises the steps of forming a base coating film and a clear coating film on a base material and then sharpening the portion of the base coating film to be repaired; And a step of applying the repair paint n times.

[0010](1) The process of sharpening the part to be repaired  The method for repairing a laminated coating film of the present invention comprises the steps of:
After forming the clear coating film and repairing the base coating film
It includes a step of sharpening the target portion.

[0011]Base material  In the present invention, the substrate is not particularly limited and examples
For example, metals, glass, plastics, foams and castings
And the like. Preferably, iron, copper, aluminum
Metals such as nickel, tin, and zinc, and
Alloys, specifically, passenger cars, trucks,
Vehicle bodies such as bikes and buses and parts thereof.
These metals are converted in advance with phosphate, chromate, etc.
What is done is especially preferable on rust prevention.

[0012] If necessary, an undercoat film using an electrodeposition paint and an intermediate coat film using an intermediate paint may be formed on the substrate. As the electrodeposition paint, a cationic type and an anion type can be used, but the cationic type electrodeposition paint gives a coating film excellent in anticorrosion properties.

The above-mentioned intermediate coating is formed to conceal underlying defects, to ensure surface smoothness after top coating and to provide chipping resistance, and to use various organic and inorganic coloring pigments and extenders. Contains pigments. As a standard, a gray intermediate coating having carbon black and titanium dioxide as main pigments is often used, but a so-called color intermediate coating obtained by combining various coloring pigments can also be used. The electrodeposition paint and the intermediate coating are not particularly limited, for example,
What has been widely used than before can be mentioned,
These coating films can be formed according to a conventional method.

[0014]Base coating  In the present invention, the base coating film is a metallic base
It is preferably a coating film. That is, light brightness and sharpness
Meta that can be obtained by using an enhanced glitter pigment at a high concentration
Rick-based coatings, especially for repaired parts
Repair part and repair part without dust ring
Exhibits the effect that there is no difference in the appearance of the coating film
Can be However, metallic base coatings
Good appearance even with solid base coatings other than
Can be obtained, the laminated coating of the present invention
Repair methods for the membrane can be applied.

[0015] The base coating film is formed of a base paint. The base paint generally contains a thermosetting resin serving as a binder and a curing agent. When the base coating film is a metallic base coating film, a base coating material further containing a glitter pigment is used.

The binder of the base paint is not particularly limited. Generally, a thermosetting resin such as an acrylic resin, a polyester resin, an alkyd resin, or a fluorine-based resin is crosslinked with an amino resin and / or a blocked polyisocyanate compound. And the like.
Suitable compositions include acrylic resin and amino resin and / or
Or the combination with a block isocyanate compound is mentioned. The solids content of the paint is generally 30 to 70% by weight at the time of production and 10 to 50% by weight at the time of application. The dry film thickness of the base coating film formed is generally 10
About 30 μm.

The glitter pigment used in the base paint is not particularly limited, and may be, for example, a metal such as aluminum, copper, zinc, iron, nickel, tin, aluminum oxide, or an uncolored or colored metal such as an alloy. Brightening agents and mixtures thereof. Further, interference mica pigments, white mica pigments, graphite pigments, and other colored and colored flat pigments may be used in combination. The average particle size (D ₅₀ ) of the glitter pigment is not particularly limited, and is, for example, 5 to 35 μm.
And more preferably about 7 to 30 μm.

The bright pigment content (PW) of the base paint
C) is not particularly limited, and is, for example, 2 to 15% by weight, and more practically 3 to 14% by weight, based on the solid content in the paint. If the amount is less than 2% by weight, a metallic feeling having flip-flop properties may not be sufficiently provided, and if the amount exceeds 15% by weight, the gloss of the obtained coating film tends to decrease.

The coating form of the base coating may be any of an organic solvent type, an aqueous type (water-soluble, water-dispersible, emulsion) and a non-aqueous type. Furthermore, in the base paint,
If necessary, an organic / inorganic coloring pigment and / or extender may be used in combination.

Further, depending on the purpose, it may contain crosslinked resin particles (microgel), a curing catalyst, an ultraviolet absorber, an antioxidant, a surface conditioner and the like. The crosslinked resin particles are insoluble in the paint system and are stably dispersed in the paint system, and are generally used as a viscosity imparting agent.
The content of the crosslinked resin particles is about 0.1 to 15% by weight based on the solid content of the resin in the paint. If it exceeds 15% by weight, the appearance of the coating film tends to decrease. If the amount is less than 0.1% by weight, it is not possible to impart appropriate viscosity.

The method for producing the base paint is not particularly limited, and any method known to those skilled in the art, such as kneading and dispersing a compound such as a pigment using a kneader or a roll, can be used. The coating of the base paint is generally performed by electrostatic coating. Specifically, air atomization (Auto RE
A), those utilizing rotary centrifugal atomization (metabell, microbell, micromicrobell) are used.

In the above electrostatic coating, the amount of paint discharged is large, and the glittering pigment in the metallic base paint is easily oriented in a random state due to the influence of static electricity. Therefore, the flip-flop property in the case of electrostatic painting has a feeling of particles of the brilliant pigment, it is a glittering feeling, compared with the hue in the case of air spray painting used for repair work.
It looks black when viewed from the highlight position and white when viewed from the shade position.

[0023]Clear coating  The clear coating film is formed from a clear paint. Up
The clear paint mainly consists of thermosetting resin and hardener.
Consisting of minutes.

The thermosetting resin is not particularly limited, and for example, a film-forming resin such as an acrylic resin, a polyester resin, an epoxy resin, and a urethane resin can be used. Alternatively, it is used in combination with a curing agent such as a blocked isocyanate resin. In terms of transparency and acid etching resistance, etc., a combination of an acrylic resin and / or a polyester resin and an amino resin, or an acid / epoxy-cured acrylic resin and / or
Alternatively, it is preferable to use a polyester resin or the like.

The solid content in the clear coating is 2
It is 0 to 60% by weight, preferably 35 to 55% by weight. The solid content at the time of application is 10 to 50% by weight, preferably 20 to 50% by weight.

The dry film thickness of the clear coating film is generally 1
It is preferably about 0-60 μm, more preferably 20-5 μm.
It is about 0 μm. If it exceeds 60 μm, inconveniences such as splashes and sagging may occur at the time of coating.

Since the clear coating is applied wet-on-wet with the base coating, it is preferable to contain a viscosity controlling agent such as a non-crosslinked or crosslinked resin or particle utilizing the interaction of a polar group.

The amount of the viscosity control agent to be added to the above clear coating composition is 0.1 to 100 parts by weight of the resin solid content of the coating composition.
0.01 to 15 parts by weight, preferably 0.02 to 10 parts by weight, more preferably 0.03 to 8 parts by weight. If the amount is more than 15 parts by weight, the appearance of the resulting coating film will be reduced. If the amount is less than 0.1 part by weight, the effect of controlling the viscosity cannot be obtained, and it will cause the layer to adapt or reverse.

As the form of the clear paint used in the present invention, a solution type is preferably used. If the solution type is a solution type, an organic solvent type, an aqueous type (water-soluble, water-dispersible, emulsion), a non-aqueous type Either may be used. If necessary, a curing catalyst, a surface preparation agent and the like can be used. The application of the clear coating can be generally performed by electrostatic coating or spray coating.

[0030]Parts to be repaired  In the present invention, the base coating film and the coating
After forming the rear coating, the repair target part of the base coating is
Be sharpened. The part to be repaired is sharpened on the substrate
After the base coat and clear coat are formed on the
Normal or dust is formed on or below the base coating layer
Is performed when it is recognized in the intermediate coating layer etc.
is there. In the present invention, the base coating film and the clear
-Not only when sharpening the coating film,
The intermediate coating film, base coating film and clear coating film
When sharpening, electrodeposition coating (undercoat), intermediate coating
When sharpening the base coat, clear coat and base coat
Including. That is, when the part to be repaired of the base coating is sharpened
It is sufficient that at least the base coating is sharpened.
Is meant. The part to be repaired is
Means the area containing the part that needs to be repaired,
Concept that requires that the part to be repaired be in the base coating
is not.

When the above-mentioned sharpening is performed only on the clear coating film, a good laminated coating film can be formed by performing the sharpening and further applying the same clear coating film thereon. Therefore, the problem that dust ring occurs does not occur. Therefore, in the present invention,
At least the base coating needs to be sharpened.

The above-mentioned sharpening is performed by so-called water sharpening using, for example, an abrasive such as sandpaper. It is preferable that the repair be performed with a gentle gradient until the intermediate coating film is exposed.

[0033](2) Repair coating process  The method for repairing a laminated coating film of the present invention, the repair target portion,
This includes a step of applying the repair paint n times. Up
Note that n is 2 or more. Preferably, it is three or more. n
Is 1, the boundary between the part to be repaired and the other part
Dusty ring in the part, giving a distinctly different appearance
The Rukoto. n is larger, that is, the repair paint is applied.
The more parts to be repaired, the more parts to be repaired and other parts
The feeling of incompatibility is eliminated, and a coating film with good appearance is obtained.
However, the operation becomes complicated. Furthermore, paint color, repair target part
Since the suitable n can change depending on the area of the minute, etc.,
It is preferable to determine n according to these factors.

In the present invention, the i-th repair paint with n ≧ i has a lower pigment concentration than the (i-1) -th repair paint. That is, in the present invention, the repair paint is applied n times, but the repair paint used at any i-th one of the n paints is the repair paint used at the (i-1) -th time immediately before the i-th paint. The pigment concentration is lower than that of the pigment. By successively using the repair paint in which the pigment concentration is reduced stepwise, the boundary between the repair target portion and the other portion is not clear, so that a dust coating does not occur and a good coating film is formed. Appearance can be obtained.

In the present invention, the repair paint used for the first time is preferably the same as the base paint forming the base coating film. The same base paint that forms the base coating has a high hiding power at the sharpened part,
The number of times n that the repair paint is applied can be reduced.

Further, the repair paint used in the second and subsequent times is preferably one obtained by mixing the base paint and the correction clear paint containing no pigment. In the present specification, the correction clear paint is used by being mixed with the above-mentioned base paint, and means a paint used for adjusting the pigment concentration of the repair paint.

The above-mentioned correction clear paint contains a thermosetting resin and a curing agent as a binder, and further contains, according to the purpose, crosslinked resin particles (microgel), a curing catalyst, an ultraviolet absorber, an antioxidant, and a surface conditioner. , Silica particles and other additives. Since the above-mentioned correction clear paint is used for lowering the pigment concentration of the repair paint by being mixed with the base paint, it is preferable that the paint does not contain a pigment. As each component contained in the correction clear, those exemplified for the base paint can be exemplified.

In the present invention, it is preferable that the correction clear coating composition be substantially the same as the base coating composition except for the pigment in the base coating composition, for the purpose of wet-on-wet coating. The fact that the composition other than the pigment in the base paint is substantially the same as the base paint means that the compounding ratio between the film-forming resin serving as a binder and the curing agent, and the resin solid content and the purpose are added according to the purpose. The mixing ratio with the additive and the solid content in the paint were 10% and 10%, respectively.
It means that the difference is not more than% by weight. In this case, it is preferable that the types of the film-forming resin, the curing agent, and the additives added according to the purpose to be used are the same as those in the base paint. In any case, the application of the repair paint can be performed by wet-on-wet spray coating.

The present invention includes a step of applying the repair paint to the portion to be repaired n times and then finally applying a clear paint. As the clear paint, the above-mentioned clear paint which is the same as that on which the repaired coating film is formed, or a clear paint dedicated to repair can be used. There is no particular limitation as long as it does not hinder the design properties of the repair coating film as a base, but it is possible to use the same clear paint as that which formed the repair coating film to make the appearance and physical properties of the whole substrate uniform. It is preferable from the point of formation.

Next, the thus-obtained laminated coating film is simultaneously cured by heating under predetermined conditions. Curing conditions vary depending on the type of resin used for each coating material.
Can be heated for 30 minutes.

The method for repairing a laminated coating film of the present invention can be suitably used for automobiles or automobile parts requiring an excellent appearance of the coating film. The automobile or automobile part having the laminated coating repaired by the method for repairing a laminated coating according to the present invention has a repaired portion and a repaired portion in which the appearance and appearance of the coating are repaired without dulling occurring in the portion to be repaired. It can be made the same in other coating films.

[0042]

FIG. 1 is a sectional view of a portion to be repaired which has been repaired according to a preferred embodiment of the present invention. In FIG. 1, after forming an intermediate coating film 2, a base coating film 3, and a clear coating film 4 on a substrate 1 on which an electrodeposition coating film is formed, a repair target portion 5 is sharpened. In the present invention, the repair target portion 5 is sharpened so as to reach at least the base coating film.

Using the same paint as the base paint on which the base paint film 3 was formed as the first repair paint, the above-mentioned repair target portion 5 was spray-coated over a slightly wider range than the base paint sharpening range 6. A second repair coating 7 is formed.
Next, the base paint on which the base coating film 3 is formed and the correction clear paint are mixed to prepare a second repair paint having a reduced pigment concentration. This second repair paint is spray-coated on the first repair paint film 7 by wet-on-wet to form a second repair paint film 8. Further, the base paint on which the base coating film 3 is formed and the correction clear paint are mixed to prepare a third repair paint in which the pigment concentration is lower than that of the second repair paint. Apply this third repair paint in 2
The third repair coating film 9 is formed by wet-on-wet spray coating on the third repair coating film 8.

For the second repair coating, for example, a mixture of the base coating and the correction clear coating not containing pigment at a volume ratio of 1: 1 to reduce the pigment concentration to 1/2 is used. As the third repair paint, for example, a paint having a pigment concentration of 1/3 by mixing at a volume ratio of 1: 2 may be used, and the repair paint can be easily prepared.

Further, it is preferable that the first repair paint having a high hiding power is applied to a narrow area only of the sharpened portion, and that the second and subsequent repair paints are successively applied by increasing the paint area. As described above, the step of applying the repair paint n = 3 times can be performed. FIG. 1 shows the case where the repair paint is applied three times, but it is also possible to apply more paints.

After performing the step of applying the repair paint, the clear paint is spray-coated wet-on-wet to form the repair clear coating film 10. It is preferable to use the same clear paint as the clear paint on which the clear coating film 4 is formed. Thereafter, baking hardening is performed to complete the entire repair process.

[0047]

EXAMPLES The present invention will be described in detail with reference to specific examples, but the present invention is not limited to the following examples. Parts and% mean parts by weight and% by weight, respectively.

Preparation Example 1 Preparation of repair paint 1 Silver metallic base paint 10 having the composition shown in Table 1
To 0.00 parts by weight, 35.23 parts by weight of the corrected clear (VS 42.84%) having the composition shown in Table 1 was mixed.
A repair paint 1 having a PWC of 7.50% was prepared. PWC (pigment concentration) in Table 1 is the total concentration of the coloring component and the glitter.

In Table 1, the thermosetting acrylic resin had a hydroxyl value of 45, an acid value of 15, a number average molecular weight of 21,000, and a solid content of 50% by weight, and the melamine resin was Euban 20N6.
0 (butylated melamine resin manufactured by Mitsui Toatsu Co., solid content 60% by weight), aluminum pigment paste was Alpaste 91
-0562 (Toyo Aluminum Co., Ltd., average particle size 16μ)
m, solid content 72%), and the blue pigment is Shanin Blue G-
314 (manufactured by Sanyo Dye Co., solid content 100%); carbon black pigment: Monarch 1400 (manufactured by Cabot Corporation; solid content: 100%); violet pigment: Hostaperm Violet RL NFNFVP336 (manufactured by Hoechst Japan Co., Ltd .;
Solid content 100%), and the crosslinked resin particles have an average particle size of 55n.
m, a solid content of 20% was used.

[0050]

[Table 1]

Preparation Example 2 Preparation of Repair Paint 2 100.00 parts by weight of the silver metallic base paint was mixed with 105.69 parts by weight of the correction clear, and PW
A repair paint 2 of C5.00% by weight was prepared.

Example 1 (Preparation of Evaluation Coating Film) A repair coating film for evaluation was prepared by the following procedure. 0.8mm thick, zinc phosphate treated, 15
A cationic electrodeposition paint “Power Top U-80” (Nippon Paint Co., Ltd., cationic electrodeposition paint) is electrodeposited on a dull steel plate of cm × 30 cm so as to have a dry film thickness of 20 μm. For 30 minutes to form an electrodeposition coating film. Next, on the obtained electrodeposition coating film, a gray intermediate coating material “Olga P-2 Gray” (manufactured by Nippon Paint Co., Ltd., polyester / melamine resin-based coating material) was applied with a dry film thickness of 40 μm.
m and sprayed at 140 ° C. for 20 minutes to form an intermediate coating film.

Hereinafter, description will be made with reference to FIG. The silver metallic base paint shown in Table 1 was electrostatically applied on the obtained intermediate coating film 2 in two stages of a microbell and a metalbell so that the dry film thickness became 18 μm. After an interval of 5 minutes, spray a clear paint "Macflow O-1331 Clear" (Nippon Paint Co., Ltd., acid / epoxy curable acrylic resin paint) with a wet-on-wet so that the dry film thickness becomes 35 [mu] m. It was coated and baked at 140 ° C. for 20 minutes to form a metallic base coating film 3 and a clear coating film 4.

Next, the area 5 of the portion to be repaired is sharpened with water using sandpaper # 600 to form a sharpened portion until the intermediate coating film 2 in the repaired portion is sharpened. The metallic base coating film 3 and the clear coating film 4 were removed.

Using the silver metallic base paint shown in Table 1, the first repaired coating film 7 was formed by spraying the area 5 of the repaired portion, which was wider than the base sharpening range 6, by hand spraying.

After setting for 10 minutes, a second repair coating film 8 was formed using the repair coating material 1 prepared in Preparation Example 1 to a range beyond the area where the first repair coating film 7 was applied. Further, after setting for 10 minutes, the third repair coating film 9 was prepared using the repair paint 2 prepared in Preparation Example 2 in a manner wider than the range of the second repair coating film 8.
Was formed.

Next, the clear paint "Macflow O-1" was used.
331 clear "was spray-coated to form a repair clear coating film 10. The paint dust scattered in the area other than the repaired portion was wiped off with a solvent, and then left for 10 minutes for setting. Thereafter, baking was performed at 140 ° C. for 20 minutes to complete the repair coating film.

(Evaluation of Repaired Coating Film) The appearance of the coating film having the repaired portion and the unrepaired portion prepared as described above was visually compared, and evaluated according to the following criteria. 1: large discomfort 2: discomfort 3: slight discomfort 4: slight discomfort 5: no discomfort Table 2 shows the evaluation results.

[0059]

[Table 2]

Comparative Example 1 A repair coating film was formed and evaluated in the same manner as in Example 1, except that a silver metallic base paint was used instead of the repair paints 1 and 2. Table 2 shows the evaluation results.

From the results shown in Table 2, the repair coating film of Example 1 was
Since the repair paint with the pigment concentration lowered gradually was used,
There was no discomfort in the appearance of the part to be repaired and other parts. In the repair coating film of Comparative Example 1, the repair paint having a high pigment concentration was used in the three repairs, and therefore, the appearance of the portion to be repaired and that of the other portion were uncomfortable.

[0062]

In the method for repairing a laminated coating film of the present invention, by using a repair coating material in which the pigment concentration is reduced step by step, the appearance of the coating film between the repair target portion and the other portions is not discomfort. An excellent repair coating film can be obtained. This effect can be remarkably obtained especially when the base coating film is a metallic base coating film. The cause of the difference between the paint film obtained by applying the above-mentioned metallic base paint electrostatically and the paint film obtained by spray painting lies in the discharge amount of paint and the effect of static electricity. The brilliant pigment in the medium is easily oriented in a random state, whereas the amount of the paint discharged is extremely small when applied by spray coating (for example, about 1/4 of the discharge amount of electrostatic coating). Therefore, the glitter pigment is easily oriented in the coating film in a state parallel to the substrate.

Accordingly, with respect to flip-flop properties, the electrostatically applied coating film had a brilliant pigment particle feeling and a glittering feeling, was black when viewed from the highlight position, and was viewed from the shade position. It looks white in some cases. On the other hand, a spray-painted film looks like a solid aluminum powder, becomes white as the brightness increases when viewed from the highlight position, and when viewed from the shade position Becomes black. It is presumed that such a difference in the orientation of the brilliant pigment causes a difference in appearance between the coating film obtained by electrostatically coating the metallic base paint and the coating film obtained by spray coating in the repairing process. However, according to the method for repairing a laminated coating film of the present invention, since a repair paint having a gradually reduced pigment concentration is used, even when applied by hand-blown air spray, the orientation of the glitter pigment is the same as the random state. It is possible to make the appearance of the metallic base coating film in the repaired portion and the unrepaired portion not uncomfortable.

Further, the method for repairing a laminated coating film of the present invention can perform repair work with no variation in finish, and can be repaired even by a person who is not skilled in repair work. In addition, when a paint obtained by mixing a base paint and a correction clear paint is used as a repair paint, there is no need to prepare a special repair paint for each paint color in advance, and it is used for any paint color. Uses a highly versatile correction clear paint that eliminates the need for complicated toning work and preparation.
Repair work can be performed easily.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a laminated coating repaired according to a preferred embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate on which electrodeposition coating film was formed 2 Intermediate coating film 3 Base coating film 4 Clear coating film 5 Repair target portion 6 Base coating sharpening range 7 First repair coating film 8 Second repair coating film 9 3 The first repair coating 10 The repair clear coating

Claims (5)

[Claims] 1. A step of forming a base coating film and a clear coating film on a base material, then sharpening a repair target portion of the base coating film, and applying a repair paint n times to the repair target portion. A method for repairing a laminated coating film comprising a step of coating, wherein n is 2 or more and n ≧ i, the i-th repair paint is more pigment-based than the (i-1) -th repair paint. A method for repairing a laminated coating film having a low concentration. 2. The method according to claim 1, wherein n is 3 or more. 3. The method according to claim 1, wherein the base coating film is a metallic base coating film. 4. The first repair paint is the same as the base paint forming the base coating film, and the second and subsequent repair paints comprise the base paint and the correction clear paint containing no pigment. 3. The composition of claim 1, which is obtained by mixing.
Or the method for repairing a laminated coating film according to item 3. 5. An automobile or an automobile part having a laminated coating repaired by the method for repairing a multilayer coating according to claim 1, 2, 3, or 4.