JP7697288B2 - Method for forming a peelable coating film - Google Patents

Description

This disclosure relates to a method for forming a peelable coating film.

There is a technology that applies a peelable paint to the surface of a vehicle such as an automobile to form a coating, thereby protecting the coating of the vehicle during transportation from the factory and/or during storage. The protective coating can be removed from the vehicle with a high-pressure washer or the like before delivery to the user.

Peelable coatings are also used to decorate the exterior of vehicles. Peelable coatings are easier to peel off than regular paints, so the exterior of a vehicle can be easily changed. For example, the exterior of a vehicle can be decorated by applying a paint for peelable coatings to the exterior surface of the vehicle, and then applying a color base paint and/or clear paint on top of that. Furthermore, if you want to change or remove the decoration, you can easily do so by removing the peelable coating with a high-pressure washer, adhesive, etc.

For example, Patent Document 1 discloses a method for protecting the appearance of an automobile body, which continuously protects the appearance of the automobile body after painting is completed from the assembly process to delivery to the user, and is characterized by applying a physically peelable protective coating to the paint film surface of the automobile body.

Japanese Patent Application Publication No. 06-254488

As described above, peelable coatings are used to protect and decorate the exterior surface of a vehicle. Here, peelable coatings for protection and decoration must be sufficiently adhered to the surface of the vehicle until the need arises to intentionally peel them off. For example, a high-pressure washer is used to clean dirt and dust adhering to the surface of a peelable coating, but a peelable coating for protection and decoration is desired to have a characteristic that it cannot be peeled off with the water pressure used in general cleaning, and can only be peeled off when even higher water pressure is applied using a high-performance high-pressure washer for commercial use, etc. In other words, it is desirable for a peelable coating to have a moderate durability that does not peel off at low water pressure but peels off at high water pressure, and it is desired to develop a method for forming a peelable coating that can be adjusted so that the peelable coating has such durability.

Therefore, the present disclosure aims to provide a method for forming a peelable coating film that can adjust the durability of the peelable coating film.

The inventors of the present invention have conducted extensive research to solve the above problems, and have discovered that when forming a peelable coating film on the design surface of a component that constitutes the exterior surface of a vehicle, forming the peelable coating film so that the thickness of the outer edge of the coating film is greater than the thickness of the coating film in other areas can improve durability against pressures such as water pressure from a high-pressure washer, leading to the present disclosure.

Therefore, examples of this embodiment are as follows:

(1) A method for forming a peelable coating film on a design surface of at least one part constituting an exterior surface of a vehicle, comprising the steps of:
A method comprising the step of applying a peelable coating such that the thickness of the outer edge of the peelable coating is greater than the thickness of the coating in other areas.
(2) The method according to (1), wherein the surface of the part is painted.
(3) The method according to (2), wherein the surface of the part is a color base coating or a clear coating.
(4) The method according to any one of (1) to (3), wherein the outer edge of the peelable coating film is disposed near an end of the design surface of the part.
(5) The method according to any one of (1) to (4), further comprising the step of applying a color base coating after the step of applying the peelable coating.
(6) The method according to (5), further comprising the step of applying a clear coating film after the step of applying the color base coating film.
(7) The method according to any one of (1) to (4), further comprising the step of applying a clear coating after the step of applying the peelable coating.
(8) The method according to any one of (1) to (7), wherein the thickness of the outer edge of the peelable coating film is 50 μm or more and 300 μm or less.
(9) The method according to (8), wherein the thickness of the outer edge of the peelable coating film is at least 10 μm greater than the thickness of the coating film in the other portions.
(10) The method according to (8) or (9), wherein the coating film in the other portion has a thickness of 10 μm or more and 40 μm or less.
(11) The method according to any one of (1) to (10), wherein the peelable coating film is formed to decorate the exterior of a vehicle.
(12) The method according to any one of (1) to (10), wherein the peelable coating film is formed to protect the exterior surface of a vehicle.

This disclosure provides a method for forming a peelable coating film that allows adjustment of the durability of the peelable coating film.

FIG. 1 is a schematic perspective view showing one embodiment of the present invention. FIG. 1 is a schematic diagram for explaining the positional relationship between a sample consisting of a substrate 1001 and a peelable coating film 1002 and a nozzle 1003 of a high-pressure cleaner in a durability evaluation.

This embodiment is a method for forming a peelable coating film on the design surface of at least one component that constitutes the exterior surface of a vehicle, and includes a step of applying the peelable coating film so that the film thickness of the outer edge of the peelable coating film is greater than the film thickness of the other parts.

In this embodiment, the peelable coating film is formed so that the thickness of the coating film at the outer edge of the peelable coating film is larger than the thickness of the coating film at other parts. In this embodiment, by making the coating film at the outer edge thicker, the durability of the peelable coating film against pressure such as water pressure by a high-pressure washer can be improved. In general, when peeling off a peelable coating film by spraying water or a solvent with a high-pressure washer, the coating film tends to peel off easily from the outer edge of the coating film, where the part between the coating film and the part surface appears. It is thought that the coating film tends to peel off easily from the outer edge because the water or solvent sprayed at high pressure is likely to penetrate into the interface between the coating film and the part surface that appears at the outer edge. Therefore, the inventors of the present invention have studied diligently and found that the durability of the coating film against pressure such as water pressure by a high-pressure washer can be improved by thickening the coating film at the outer edge. The following reasons are speculated as the reason why durability against pressure such as water pressure is improved by increasing the thickness of the coating film at the outer edge. As described above, a peelable coating film tends to peel off when sprayed water or solvent penetrates the interface between the coating film and the surface of the part, which appears at the outer edge of the coating film. If the coating film is thin, the coating film is more likely to deform or break, and the sprayed water or the like is more likely to penetrate the interface. Therefore, by increasing the thickness of the outer edge, the strength of the outer edge is improved, and deformation or breakage of the coating film caused by sprayed water or the like at the outer edge is suppressed, and as a result, the sprayed water or the like can be suppressed from penetrating the interface. Therefore, it is believed that by increasing the thickness of the outer edge, durability against pressure such as water pressure can be improved. Note that this assumption does not limit the present embodiment.

This embodiment is described in detail below.

The forming method according to this embodiment includes a step of applying a peelable coating film so that the film thickness of the outer edge of the peelable coating film is greater than the film thickness of the other parts of the coating film. In other words, the forming method according to this embodiment includes a step of applying paint for the peelable coating film so that the film thickness of the outer edge of the peelable coating film is greater than the film thickness of the other parts of the coating film.

The peelable coating film is formed for the purpose of adhering to the surface of the part until a predetermined timing for protection or decoration, and peeling off as necessary. The peelable coating film is required to be sufficiently adhered to the surface of the vehicle until it becomes necessary to intentionally peel it off. For example, even when dirt and dust attached to the surface of the peelable coating film are washed with a high-pressure washer, it is desired that the coating film has such durability that it will not peel off with the water pressure used in general washing. On the other hand, when peeling off, it is desired that it can be peeled off with high water pressure, such as that obtained by using a high-performance high-pressure washer for commercial use. Therefore, in this embodiment, the coating film is formed so that the film thickness of the outer edge of the peelable coating film is larger than the film thickness of the coating film in other parts. This can improve the durability of the coating film at the outer edge, which tends to peel off easily, and improve the overall resistance of the coating film to peeling off.

The "outer edge" of the peelable coating film is a portion along the outer edge of the peelable coating film. In this embodiment, from the viewpoint of obtaining the durability improvement effect of this embodiment, it is sufficient that the coating film is thick at least in a part of the outer edge. In this embodiment, from the viewpoint of the durability improvement effect, it is preferable that the outer edge portion where the coating film is thick is arranged on more than half of the outer edge of the peelable coating film. Also, in this embodiment, from the viewpoint of the durability improvement effect, it is preferable that the outer edge portion where the coating film is thick is arranged on the entire outer edge of the peelable coating film. In other words, in this embodiment, from the viewpoint of the durability improvement effect, it is preferable that the coating film is thick on the entire outer edge of the peelable coating film. In other words, in this embodiment, it is preferable that the coating film is thick along the entire outer edge of the peelable coating film.

In this embodiment, the peelable coating film is formed on the design surface of at least one component that constitutes the exterior surface of the vehicle. The design surface may be flat or curved.

In this specification, "exterior surface of a vehicle" means the surface of a vehicle that is exposed to the outside when all openings, such as doors, of a vehicle such as an automobile are closed. In this specification, "at least one part constituting the exterior surface of a vehicle" means a part at least a portion of which is exposed to the exterior surface of the vehicle, and there may be one or more parts on which a peelable coating film is formed. In this specification, "design surface of a part" means the surface of a part that is visible from outside the vehicle, and may also be referred to as the exterior surface of the part.

The parts constituting the exterior surface of the vehicle are not particularly limited as long as at least a part of them is exposed to the exterior surface of the vehicle. Examples of parts constituting the exterior surface of the vehicle include a bonnet, a roof, a fender, a front pillar, a rear pillar, a center pillar, a front door, a rear door, a side panel, an outside door handle, a front bumper, a rear bumper, a tire wheel, a door mirror, a trunk, a quarter panel, an emblem, and the like. In general, a coating film is applied to the surface of the parts constituting the exterior surface of the vehicle. The surface of the parts constituting the exterior surface of the vehicle may be a glass member, and examples of the glass member include a window glass or a light glass. Examples of the window glass include a front glass, a side glass, or a rear glass. Examples of the light glass include a headlight glass, a small light glass, a turn signal glass, a tail light glass, a brake light glass, or a fog light glass. As described above, in this embodiment, the part on which the peelable coating film is formed may be one or more.

Examples of parts as objects to be coated include metal materials (iron plates, steel plates, aluminum, stainless steel, etc.) or resin materials that have been coated with paint. For example, when coating, a primer layer is formed on the metal material or resin material, and a color base paint and/or clear paint is applied on the primer layer. The primer layer is a paint or resin film, and can be formed on the surface of the part by electrocoating. The primer layer has the role of ensuring corrosion resistance and adhesion with the color base paint or clear paint. Unlike the peelable coating film formed in this embodiment, these coating films are not intended to be peeled off in the future. The paint is not particularly limited, but usually contains a resin and a hardener. The resin that is the main element of the coating film is not particularly limited, but is preferably an aqueous resin. The aqueous resin may be a water-soluble resin that can be dissolved in water or a water-dispersible resin that can be dispersed in water. Examples of resins contained in the paint include epoxy resins, epoxy ester resins, polyester resins, acrylic resins (including methacrylic resins), acrylic silicone resins, polyester resins, polyurethane resins, alkyd resins, urethane resins, vinyl resins, urea-based resins, styrene-butadiene-latex (SBR), and NBR. The aqueous resins may be used alone or in combination of two or more.

In this embodiment, it is preferable to form a peelable coating film on a painted part. The peelable coating film may be formed to protect the paint on the part, or may be formed to decorate the part surface. In one embodiment, a peelable coating film is formed on the color base coating film and/or the clear coating film. In one embodiment, a peelable coating film is formed on the color base coating film. In one embodiment, a peelable coating film is formed on the clear coating film. Examples of resins used in the clear paint include acrylic resins, polyester resins, alkyd resins, urethane resins, and epoxy resins. The resins may be used alone or in combination of two or more. The clear paint may also contain a crosslinking agent. Examples of crosslinking agents include polyisocyanates, melamine resins, and urea resins. The crosslinking agents may be used alone or in combination of two or more. The clear paint may be, for example, a paint in which a resin, a crosslinking agent, and an additive are dissolved or dispersed in an organic solvent or water. In addition, from the standpoint of transparency or reinforcing properties, it is preferable that the clear coating contains acrylic resin and/or polyester resin as a binder component.

In this embodiment, the outer edge of the peelable coating film is preferably positioned near the edge of the design surface of the part. By positioning the outer edge of the peelable coating film near the edge of the design surface of the part, the protection range or decoration range of the design surface of the part can be widened. In this embodiment, the outer edge of the peelable coating film is preferably positioned in contact with the edge of the design surface of the part.

Figure 1 is a schematic perspective view showing one embodiment of this embodiment. The vehicle 100 shown in Figure 1 has a painted bonnet 10, and a peelable coating film 1 is applied onto the bonnet 10. The peelable coating film 1 has an outer edge portion 1a and an inner portion 1b corresponding to the inside of the outer edge portion, and is formed so that the film thickness of the outer edge portion 1a is greater than the film thickness of the inner portion 1b. In addition, the outer edge portion 1a is located near the edge of the design surface of the bonnet 10, and specifically, the outer edge of the peelable coating film is formed to fit along the edge of the design surface of the bonnet 10.

In FIG. 1, a painted bonnet 10 is shown as an example of a part to which a peelable coating film is applied, but this embodiment is not limited to this. For example, the peelable coating film may be applied to at least one part selected from the bonnet, roof, fender, front pillar, rear pillar, center pillar, front door, rear door, side panel, outside door handle, front bumper, rear bumper, tire wheel, door mirror, trunk, quarter panel, and emblem.

In this embodiment, from the viewpoint of effectively improving durability, the outer edge where the coating film is thickened is preferably 5 mm or more from the outer edge, and preferably 10 mm or more from the outer edge. Furthermore, from the viewpoint of reducing the amount of coating film used and costs such as labor, the outer edge where the coating film is thickened is preferably 50 mm or less from the outer edge, preferably 40 mm or less from the outer edge, and preferably 30 mm or less from the outer edge. The upper and/or lower limit values of these numerical ranges can be arbitrarily combined to define a preferred range.

The film thickness of the outer edge is preferably 50 μm or more, preferably 55 μm or more, preferably 60 μm or more, preferably 65 μm or more, preferably 70 μm or more, and preferably 75 μm or more. By increasing the film thickness of the outer edge, the durability of the coating film against pressure such as water pressure from a high-pressure washer can be improved. In addition, the film thickness of the outer edge is preferably 300 μm or less, preferably 250 μm or less, preferably 200 μm or less, and preferably 150 μm or less. The upper and/or lower limits of these numerical ranges can be arbitrarily combined to define a preferred range.

The thickness of the coating at the outer edge is preferably at least 10 μm larger than the thickness of the coating other than the outer edge, and more preferably at least 20 μm larger.

The film thickness other than the outer edge is preferably 40 μm or less, preferably 35 μm or less, and preferably 30 μm or less. By setting the film thickness other than the outer edge within this range, the coating film can be easily peeled off after the coating film on the outer edge has peeled off, and the amount of paint used and labor costs can be effectively reduced. Furthermore, the film thickness other than the outer edge is preferably 10 μm or more, preferably 15 μm or more, and preferably 20 μm or more. By setting the film thickness other than the outer edge within this range, the durability of the coating film other than the outer edge can be improved. The upper and/or lower limits of these numerical ranges can be arbitrarily combined to define a preferred range.

The paint for the peelable coating film is not particularly limited, and any paint used for forming a coating film intended to be peeled off can be used. The paint for the peelable coating film is, for example, a resin-containing liquid in which at least a resin is dissolved or dispersed in a solvent. Examples of the solvent include water and organic solvents. Specifically, the paint for the peelable coating film is, for example, a resin-containing liquid in which at least a resin is dissolved or dispersed in an organic solvent. The paint for the peelable coating film is, for example, a water-dispersed resin composition in which at least a resin is dissolved or dispersed in water. As the water-dispersed resin composition, one in which a resin is dispersed in the presence of a surfactant is usually used, but as long as the resin is dispersed in water, one in which the resin is self-dispersed in water and becomes an aqueous dispersion can be used. The water-dispersed resin composition may be an emulsion, and is preferably an emulsion-type resin composition using a polymer emulsion obtained by emulsion polymerization.

The organic solvent is not particularly limited, but examples thereof include the following: Alcohol-based solvents such as methanol, ethanol, propanol, butanol, pentanol, hexanol, octanol, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, and diethylene glycol monoethyl ether. Aliphatic hydrocarbon-based solvents such as pentane, hexane, octane, decane, and cyclohexane. Aromatic hydrocarbon-based solvents such as benzene, toluene, xylene, ethylbenzene, mesitylene, cumene, pseudocumene, tetralin, and chlorobenzene. Ester-based solvents such as ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, ethylhexyl lactate, amyl lactate, isoamyl lactate, ethoxyethyl propionate, and γ-butyrolactone. Examples of the organic solvent include ketone-based solvents such as methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, and cyclohexanone. Halogenated aliphatic hydrocarbon-based solvents such as methylene chloride and chloroform. Ether-based solvents such as 1,4-dioxane, tetrahydrofuran, ethylene glycol dimethyl ether, diisopropyl ether, diisobutyl ether, cyclopentyl methyl ether, anisole, and diphenyl ether. Examples of the organic solvent include aprotic polar solvents such as dimethyl sulfoxide, sulfolane, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, acetonitrile, and propionitrile. These organic solvents may be used alone or in combination.

As the resin, various resins can be used, and there is no particular limitation. For example, silicone-based resins, acrylic-based resins, polystyrene-based resins, rubber-based resins, polyurethane-based resins (urethane-based resins), vinyl alkyl ether-based resins, polyvinyl alcohol-based resins, polyvinylpyrrolidone-based resins, polyacrylamide-based resins, cellulose-based resins, polyester-based resins, fluorine-based resins, etc. are listed. Among these, silicone-based resins, acrylic-based resins, and polystyrene-based resins are preferred. The resins may be used alone or in combination of two or more. The content of the resin component in the resin-containing liquid is preferably 5 to 95% by mass, preferably 10 to 90% by mass, preferably 15 to 80% by mass, preferably 20 to 70% by mass, and preferably 25 to 60% by mass.

The resin-containing liquid may contain a release agent, a film-forming aid, or a crosslinking agent.

A release agent is an additive that adjusts the adhesive strength of the formed coating film and helps it to be peeled off from the adherend. By including a release agent, the coating film formed by the water-dispersed resin composition and the surface of the part to be protected (e.g., the coating film) tend to have a moderate adhesion. As the release agent, at least one compound selected from surfactants, polyhydric alcohols, and waxes can be suitably used. These can be used in either the form dissolved or dispersed in water, or in the form of a powder. Examples of surfactants include anionic surfactants, nonionic surfactants, and amphoteric surfactants. Examples of polyhydric alcohols include ethylene glycol, propylene glycol, glycerin, catechol, butanediol, pentanediol, erythritol, glycerin monoalkyl ester, polyethylene glycol, and polypropylene glycol. Specific examples of waxes include plant-based waxes such as candelabra wax, carnauba wax, rice wax, Japan wax, and jojoba oil; animal-based waxes such as beeswax, lanolin, and spermaceti; mineral-based waxes such as montan wax, ozokerite, and ceresin; petroleum-based waxes such as paraffin wax, microcrystalline wax, and petrolatum; synthetic hydrocarbon-based waxes such as Fischer-Tropsch wax, oxidized polyethylene wax, polyethylene wax, and acrylic-ethylene copolymer wax; modified wax-based waxes such as montan wax derivatives, paraffin wax derivatives, and microcrystalline wax derivatives; hydrogen-based waxes; hydrogenated castor oil, hydrogenated castor oil derivatives, and others; 12-hydroxystearic acid, stearic acid amide, phthalic anhydride imide, bisamide, amide, glycerin ester, sorbitan ester, higher alcohols (C12 or more, preferably C16 or more), and higher fatty acids (C12 or more, preferably C16 or more). These may be used alone or in combination of two or more.

A film-forming aid is an additive that aids in the formation of a coating film. After a coating film is formed, the film-forming aid evaporates relatively quickly, providing a temporary plasticizing function that improves the strength of the coating film. An organic solvent with a boiling point of 110 to 200°C is preferably used. For example, when the water-dispersed resin composition is an emulsion containing a resin component, by adding a film-forming aid, film formation becomes possible in a room temperature environment even for resin components whose MFT (minimum film forming temperature) is room temperature (15 to 35°C) or higher, and a highly uniform coating film can be obtained. Specific examples include Texanol, propylene glycol monobutyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol monobutyl ether, ethylene glycol mono-normal-butyl ether, diethylene glycol diethyl ether, dipropylene glycol monopropyl ether, carbitol, butyl carbitol, dibutyl carbitol, N-methyl-2-pyrrolidone, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, and benzyl alcohol. Among these, Texanol and ethylene glycol mono-normal-butyl ether are particularly preferred because they have a high film-forming auxiliary effect even in small amounts. The film-forming auxiliary may be used alone or in combination of two or more types.

Examples of crosslinking agents include photocuring agents such as photocuring monomers and photocuring oligomers, isocyanate-based crosslinking agents, epoxy-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, carbodiimide-based crosslinking agents, and metal chelate-based crosslinking agents. These crosslinking agents react with functional groups such as hydroxyl groups and carboxyl groups introduced into the base polymer to form a crosslinked structure. As the crosslinking agent, a photocuring monomer, a photocuring oligomer, or an isocyanate-based crosslinking agent is preferred because it has high reactivity with the hydroxyl groups and carboxyl groups of the base polymer and is easy to introduce a crosslinked structure. Only one type of crosslinking agent may be used alone, or two or more types may be used in combination.

The resin-containing liquid may contain oil. Examples of oil include silicone oil, liquid paraffin, surfactants, liquid hydrocarbons, fluorinated oils, wax, petrolatum, animal fats, and fatty acids. One type of oil may be used alone, or two or more types may be used in combination. When the resin-containing liquid contains such oil, the antifouling effect of the coating film may be more fully exerted, and adhesion of dirt may be effectively prevented for a long period of time.

The resin-containing liquid may contain other additives. Examples of such other additives include thickeners, colorants, UV absorbers, light stabilizers, antibacterial agents, antioxidants, defoamers, biological repellents, and fillers.

Fillers and the like can be added to the resin-containing liquid to improve strength. Examples of fillers include silica, titanium oxide, alumina, calcium carbonate, magnesium hydroxide, mica, kaolin, talc, carbon black, layered silicates, clay minerals, diatomaceous earth, and the like. By adjusting the particle size within the above range, sufficient strength can be imparted to the coating film, and the particles can be uniformly dispersed in the coating film, making it less likely for cracks to occur when the coating film is subjected to impact.

The resin-containing liquid can be applied to the surface of the part and dried to form a coating film. After the resin-containing liquid is applied to the surface of the part, the applied coating may be heated as necessary. The heating may be for the purpose of drying or for the purpose of hardening.

The application method is not particularly limited, and can be any known application method such as spray, brush, roller, curtain flow, roll, dip, coater, etc.

One example of a method for coating a peelable coating so that the outer edge of the coating is thicker than the rest of the coating is to first apply paint to the design surface of the part to form a uniform coating, and then apply more paint to the outer edge while using a mask or guard to prevent the paint from adhering to other parts.

The thickness of the peelable coating can be measured, for example, with an electromagnetic coating thickness meter (manufacturer: Fischer, product number: DELTA SCOPE FMP10). The coating thickness can be, for example, the average value of multiple locations (e.g., 10 locations).

In this embodiment, another film may be provided on the peelable coating film. Specifically, a color base coating film and/or a clear coating film may be further formed on the peelable coating film. That is, the forming method according to this embodiment may include a step of applying a color base coating film after a step of applying a peelable coating film. Also, the forming method according to this embodiment may include a step of applying a clear coating film (e.g., the above-mentioned one) after a step of applying a color base coating film. Also, the forming method according to this embodiment may include a step of applying a clear coating film after a step of applying a peelable coating film. By forming a color base coating film and/or a clear coating film, the protective strength can be further improved or further decoration can be performed.

The present embodiment will be described below using examples. Note that the following examples do not limit the present embodiment.

(Base material/material)
The substrate used was a stainless steel plate (thickness: 5 mm, size: 300 mm×300 mm) having a clear coating applied to its surface.

The main components of the paint used for the peelable coating were xylene, ethylbenzene, antioxidant, methyl ethyl ketone, silica reactant, and silicone resin containing titanium oxide (nanoparticles).

[Example 1]
The above-mentioned peelable coating paint was uniformly applied onto the above-mentioned substrate, and the peelable coating paint was then applied again to the surface edge (within a range of 10 mm from the outer periphery) of the substrate to form a peelable coating film so that the film thickness near the surface edge of the substrate was greater than the film thickness in other surface parts, thereby obtaining sample E1. The coating was performed by a spray method, and when the paint was applied again to a predetermined part, it was sprayed while being protected so that the paint was not applied to other parts. This formed a coating film having an outer edge part with a large film thickness.

The resulting peelable coating had a film thickness (10-point average) of 60 μm at the outer edge, and a film thickness of the other parts (film thickness of the inner part of the outer edge, 10-point average) of 20 μm. The film thickness was measured using an electromagnetic film thickness meter (manufacturer: Fischer, product number: DELTA SCOPE FMP10).

[Comparative Example 1]
The above-mentioned peelable coating material was uniformly applied onto the clear coating film of the above-mentioned substrate to form a peelable coating film, thereby obtaining a sample C1. The application was performed by a spray method.

The resulting peelable coating had a thickness (average of 10 points) of 20 μm.

[evaluation]
The durability of samples E1 and C1 against water pressure from a high-pressure washer was evaluated by the following method.

Figure 2 is a schematic diagram for explaining the positional relationship between a sample consisting of a substrate 1001 and a peelable coating film 1002 and a nozzle 1003 of a high-pressure washer in a durability evaluation. In the durability evaluation, the durability of the peelable coating film 1002 formed on the substrate 1001 against the water pressure of a high-pressure washer was examined by applying water pressure at a predetermined nozzle pressure to the side of the sample plate from an obliquely upward direction for 10 seconds as shown in Figure 2, and examining the nozzle pressure when the coating film peeled off. The nozzle pressure was set to 7 MPa or 9 MPa. In addition, the location to which the water pressure was applied was changed each time the water pressure was applied. The spray angle was set so that the angle between the spray direction and the plane of the sample plate was about 45°, and the spray distance was set so that the distance from the interface edge between the substrate 1001 and the peelable coating film 1002 to the spray nozzle of the nozzle 1003 was 10 cm. The results are shown in Table 1.

As shown in Table 1, in Comparative Example 1, in which the peelable coating film was formed with a uniform thickness of 20 μm, peeling occurred at a nozzle pressure of 9 MPa. On the other hand, in Example 1, in which the peelable coating film was formed so that the thickness of the inner part was 20 μm as in Comparative Example 1 and the thickness of the outer edge was 60 μm, peeling did not occur even at a nozzle pressure of 9 MPa. This shows that the nozzle pressure required for peeling can be increased by increasing the thickness of the outer edge. Although the durability of the coating film may be improved even if the peelable coating film is formed thick all over, forming the peelable coating film thick all over leads to an increase in the amount of coating, an increase in labor and time, etc., which leads to an increase in costs, and also requires the application of high pressure all over the peelable coating film. On the other hand, in this embodiment, the overall durability of the peelable coating film can be improved by simply increasing the thickness of only the outer edge, so that an increase in the amount of coating, an increase in labor and time, etc. can be suppressed, and once the outer edge is peeled off, the remaining part of the film can be easily peeled off.

As other examples and comparative examples, samples were prepared by applying a color base paint and a clear paint on the peelable coating of the above samples E1 and C1, and the durability was evaluated by the above method. As with the results obtained in Example 1 and Comparative Example 1, the nozzle pressure required for peeling could be increased by increasing the film thickness at the outer edge of the peelable coating. This confirmed that even when applying a color base paint and/or clear paint for the purpose of decoration, the durability of the peelable coating can be improved by increasing the film thickness at the outer edge.

The upper and/or lower limit values of the numerical ranges described in this specification can be arbitrarily combined to define a preferred range. For example, the upper and lower limit values of the numerical ranges can be arbitrarily combined to define a preferred range, the upper limit values of the numerical ranges can be arbitrarily combined to define a preferred range, and the lower limit values of the numerical ranges can be arbitrarily combined to define a preferred range.

The claims following this written disclosure are expressly incorporated herein into this written disclosure, with each claim standing on its own as a separate embodiment. The present disclosure includes any substitution of an independent claim with its dependent claim. Furthermore, any additional embodiments derived from the independent claim and the subsequent dependent claims are also expressly incorporated into this written specification.

Those skilled in the art can use the above description to make the most of the present disclosure. The claims and embodiments disclosed herein are merely descriptive and exemplary and should not be construed as limiting the scope of the present disclosure in any way. With the aid of the present disclosure, changes can be made to the details of the above embodiments without departing from the basic principles of the present disclosure. In other words, various modifications and improvements of the embodiments specifically disclosed in the above specification are within the scope of the present disclosure.

Although this embodiment has been described in detail above, the specific configuration is not limited to this embodiment, and any design changes that do not deviate from the gist of this disclosure are included in this disclosure.

1 Peelable coating film 1a Outer edge of peelable coating film 1b Inner part of peelable coating film 10 Bonnet 100 Vehicle 1001 Substrate 1002 Peelable coating film 1003 Nozzle of high pressure washer

Claims (12)

A method for forming a peelable coating film by spraying water or a solvent onto a design surface of at least one component constituting an exterior surface of a vehicle, comprising the steps of:
The method includes a step of applying the peelable coating film so that the thickness of the outer edge of the peelable coating film is greater than the thickness of the coating film in other portions,
A method wherein the outer edge of the peelable coating is no more than 50 mm from the outer edge of the coating . The method of claim 1, wherein the surface of the part is painted. The method according to claim 2, wherein the surface of the part is a color base coating or a clear coating. The method of any one of claims 1 to 3, wherein the outer edge of the peelable coating is disposed near an edge of a design surface of the part. The method of any one of claims 1 to 4, further comprising the step of applying a color base coating after the step of applying the peelable coating. The method according to claim 5, further comprising the step of applying a clear coat after the step of applying the color base coat. The method of any one of claims 1 to 4, further comprising the step of applying a clear coat after the step of applying the peelable coating. The method according to any one of claims 1 to 7, wherein the outer edge of the peelable coating has a thickness of 50 µm or more and 300 µm or less. The method according to claim 8, wherein the thickness of the outer edge of the peelable coating is at least 10 μm greater than the thickness of the coating in the remaining portions. The method according to claim 8 or 9, wherein the thickness of the coating film in the other portion is 10 μm or more and 40 μm or less. The method according to any one of claims 1 to 10, wherein the peelable coating is formed to decorate the exterior of a vehicle. The method of any one of claims 1 to 10, wherein the peelable coating is formed to protect the exterior surface of a vehicle.

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