JP7475990B2 - vehicle - Google Patents

Description

The present invention relates to a vehicle.

For example, the paint on the surface of vehicles such as automobiles and trains needs to be protected from the adhesion of foreign matter, sunlight, physical damage, etc. during transportation and storage from manufacture to use.

As a method for protecting such coatings, for example, a technique has been proposed in which a protective film is formed on the coating surface using an aqueous dispersion of a peelable coating agent containing an acrylic copolymer emulsion (see, for example, Patent Document 1).

The above technology is expected to provide a protective film with an appropriate level of adhesion, which is expected to protect the vehicle's paint while achieving both adhesion during transportation and storage and peelability during use.

Japanese Patent Application Laid-Open No. 9-286934

When a protective film is formed on a paint film using the conventional techniques described above, the purpose can generally be achieved if the storage period is relatively short, such as about one year. However, under long-term storage conditions (especially in high-temperature, high-humidity environments) of more than one year, water vapor in the air can penetrate the protective film and alter the paint film, causing blisters and stains, or the protective film itself can deteriorate due to exposure to sunlight, etc., resulting in a loss of appropriate adhesion (adhesion and peelability).

The present invention was made based on the above circumstances, and its purpose is to provide a vehicle coated with a paint (protective film) that has excellent moisture impermeability and appropriate adhesion (adhesion and peelability) over the long term.

One aspect of the present disclosure is
A vehicle having a painted part on its surface,
The coating section includes:
A metal structure;
A first coating film provided on the metal structure;
a second coating film provided on the first coating film;
The second coating film has an inner layer arranged so as to be in contact with a surface of the first coating film, and an outer layer arranged on the opposite side of the first coating film with the inner layer interposed therebetween,
the outer layer includes a resin and filler particles;
The inner layer contains a resin but does not contain filler particles.

The present invention can provide a vehicle coated with a coating (protective film) that has excellent moisture impermeability and adequate adhesion (adhesion and peelability) over the long term.

1 is a schematic cross-sectional view of a coating film showing a first embodiment. FIG. 2 is a schematic cross-sectional view showing an enlarged outer layer of the second coating film in FIG. 1 . FIG. FIG. 4 is a schematic cross-sectional view of a coating film showing a second embodiment. FIG. 2 is a schematic cross-sectional view of the coating film of Comparative Example 1. FIG. 2 is a schematic cross-sectional view of the coating film of Comparative Example 2. FIG. 1 is a diagram showing the measurement results of relative moisture permeability. FIG. 1 is a diagram showing the measurement results of relative peel strength.

The vehicle disclosed herein is a vehicle having a painted part whose surface is painted, the painted part comprising a metal structure, a first paint film provided on the metal structure, and a second paint film provided on the first paint film, the second paint film having an inner layer disposed so as to be in contact with the surface of the first paint film, and an outer layer disposed on the opposite side of the inner layer to the first paint film, the outer layer containing resin and filler particles, and the inner layer containing resin but not containing filler particles.

The following describes first and second embodiments of the present invention with reference to the drawings, but the present invention is not limited to the embodiments shown in the drawings. In addition, the configuration of the vehicle other than the painted parts is the same as the configuration of vehicles related to publicly known technology, so detailed description thereof will be omitted.

[First embodiment]
Fig. 1 is a schematic cross-sectional view of a paint film showing a first embodiment. The vehicle 1 has a painted portion 101 whose surface is painted, and the painted portion 101 is generally composed of a metal structure 11, a first paint film 21, and a second paint film 31 as shown in Fig. 1.

The metal structure 11 is made, for example, of sheet metal made of metal material shaped to fit the shape of the target object.

There is no particular limitation on the metal material that constitutes the metal structure 11. Examples of the metal material include steel, aluminum alloy, stainless steel, duralumin, and CFRP (carbon reinforced plastic).

The first paint film 21 is a paint film provided on the metal structure 11. The first paint film 21 is disposed on the outermost surface (the portion in contact with the outside air g) when the vehicle 1 is in use (when the second paint film 31 described later is peeled off). The first paint film 21 can be configured to have, for example, a paint having an anticorrosive function for preventing corrosion of the metal structure 11, or a base paint such as putty applied relatively thickly to correct the uneven shape of the surface of the metal structure 11, and a paint having a smooth and vivid color formed on the base paint. The first paint film 21 may be configured as a single layer or multiple layers.

The first coating film 21 is firmly attached to the metal structure 11 so that it does not easily peel off from the metal structure 11. The first coating film 21 can be configured to have a peel strength of 4 N/cm or more between the metal structure 11, for example, in a peel test using an adhesive tape peeling method that conforms to the adhesion test (cross-cut method) specified in JIS-K5600.

The thickness of the first coating film 21 can be appropriately selected depending on the type of the first coating film 21, etc. For example, if the first coating film 21 is a coating film intended to prevent rust and improve the design of the metal structure, it may have a thickness of 10 μm to 1000 μm.

The second paint film 31 is a paint film provided on the first paint film 21. The second paint film 31 is, for example, a protective film for protecting the first paint film 21, and is formed to cover the first paint film 21 when the vehicle 1 is manufactured. The second paint film 31 is peeled off from the first paint film 21 when the vehicle 1 is used.

The second coating film 31 can be composed of two or more layers, including an outer layer and an inner layer. In this embodiment, the second coating film 31 is exemplified as being composed of two layers, an outer layer 31A and an inner layer 31B.

The outer layer 31A is a layer containing resin a1 and filler particles b. The outer layer 31A is disposed so as to be located on the opposite side of the first coating film 21, sandwiching the inner layer 31B described below.

The resin a1 contained in the outer layer 31A may be, for example, a resin that has been hardened using an emulsion of an acrylic copolymer or the like.

Examples of the acrylic copolymer emulsion include:
a copolymer emulsion of one or more alkyl acrylic esters and/or one or more alkyl methacrylic esters and one or more vinyl monomers copolymerizable with these alkyl acrylic esters and/or alkyl methacrylic esters, such as vinyl acetate or hydroxyl group-containing vinyl monomers such as hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, and allyl alcohol, epoxy group-containing vinyl monomers such as glycidyl acrylate and glycidyl methacrylate, and aromatic vinyl monomers such as styrene, methyl styrene, dimethyl styrene, ethyl styrene, butyl styrene, and benzyl styrene;
Examples of the copolymer include emulsions of copolymers of a carboxyl group-containing vinyl monomer such as acrylic acid, methacrylic acid, itaconic acid, citraconic acid, crotonic acid, etc., and one or more vinyl monomers copolymerizable with the above-mentioned acrylic acid esters and/or methacrylic acid esters.

By using a resin a1 that has been cured using an acrylic copolymer emulsion, the filler particles b can be reliably bonded to each other. In addition, when forming the resin a1, it is preferable to cure it using a high-temperature treatment. The above polymers can be used alone or in combination of two or more kinds.

Filler particles b are particles dispersed in resin a1. The shape of filler particles b can be, for example, plate-like, spherical, or irregular.

Filler particles b are preferably formed of a material that is impermeable to moisture. Examples of materials constituting filler particles b include metal materials such as silver; ceramic materials such as alumina; and mineral materials such as mica.

Among these, mica is preferred. By forming the filler particles b from the above material, the moisture impermeability and light blocking properties of the outer layer 31A, which will be described later, can be further improved.

Here, we will explain why the outer layer 31A contains filler particles b. The reason why the outer layer 31A contains filler particles b is to improve moisture impermeability and light blocking properties.

First, we will explain how the outer layer 31A exhibits moisture impermeability. It is believed that the moisture impermeability of the outer layer 31A is related to the surface effect and internal effect described below.

The surface effect is an effect that prevents external moisture (such as humidity in the outside air g) from penetrating the outer layer 31A. The outer layer 31A is in a state in which the resin a1 and the filler particles b are mixed, for example, randomly. Therefore, since the filler particles b occupy at least a portion of the surface s31 of the outer layer 31A, moisture is prevented from penetrating into the outer layer 31A in proportion to the occupancy rate, and this outer layer 31A exhibits moisture impermeability.

The internal effect is an effect that prevents moisture that has penetrated the outer layer 31A from penetrating into the interior of the outer layer 31A. Since the outer layer 31A contains filler particles b, the penetrated moisture cannot penetrate linearly toward the inner layer 31B due to the obstruction of the filler particles b. Therefore, when moisture penetrates toward the inner layer 31B, the moisture penetration path L1 through which the moisture passes becomes longer than in linear penetration (see the solid line in the outer layer 31A in Figure 1), and as a result, the penetration of the moisture is suppressed.

In this way, it is believed that the presence of the outer layer 31A provides excellent moisture impermeability due to the surface and internal effects described above.

Next, we will explain how the outer layer 31A exhibits light-blocking properties. The outer layer 31A contains filler particles b, which reflect and absorb external light such as sunlight. This prevents light from reaching the inner layer 31B, and prevents deterioration of the resin a2 in the inner layer 31B, which will be described later, and therefore maintains an appropriate adhesion (adhesion and peelability) for a long period of time.

The filler particles b preferably contain plate-shaped particles. As shown in FIG. 2, the long side direction of the plate-shaped filler particles b tends to be generally oriented in the same direction as the surface direction of the surface s31 (the surface opposite the first coating film 21) of the second coating film 31. This increases the length of the moisture penetration path L1 through which moisture from the outside passes, thereby improving moisture impermeability.

In such a case, it is more preferable that the plate-shaped filler particles b contain particles whose long sides are 0.1 μm or more and 1000 μm or less and whose short sides are 1/10 or less of the long sides. This ensures that the length of the moisture penetration path L1 is secured, and effectively increases moisture impermeability.

The concentration of filler particles b in the outer layer 31A is preferably 1% by mass or more and 50% by mass or less. By setting the concentration of filler particles b in the above range, sufficient moisture impermeability can be ensured and the filler particles b can be reliably bonded to each other.

The thickness of the outer layer 31A is not particularly limited. The thickness of the outer layer 31A may be, for example, 10 μm or more and 1000 μm or less.

The inner layer 31B is a layer that contains resin a2 but does not contain filler particles b. The inner layer 31B is disposed so as to be in contact with the surface s21 of the first coating film 21.

The resin a2 constituting the inner layer 31B may be, for example, the same resin as that exemplified as the resin a1 contained in the outer layer 31A. Note that the resin a2 constituting the inner layer 31B and the resin a1 constituting the outer layer 31A may be the same resin or different resins. In this embodiment, the resin a1 and the resin a2 are made of the same material.

This allows both adhesion and peelability between the first coating film 21 and the second coating film 31. The above polymers can be used alone or in combination of two or more.

Here, the reason why the inner layer 31B does not contain filler particles will be explained. The reason why the inner layer 31B does not contain filler particles is to improve the adhesion between the first coating film 21 and the second coating film 31 and the ability to follow the surface shape. Specifically, since the inner layer 31B does not contain filler particles, the inner layer 31B itself is easily deformed, and even if the surface s21 of the first coating film 21 has uneven parts (steps, etc.) or the surface s21 of the first coating film 21 is distorted due to temperature changes, the resin a2 of the inner layer 31B follows the shape of the surface s21 of the first coating film 21 (improved surface shape followability). In addition, since the filler particles b do not directly contact the first coating film 21, the adhesion between the inner layer 31B and the first coating film 21 can be improved compared to a coating film in which the filler particles are in contact with the first coating film (for example, see FIG. 5).

The thickness of the inner layer 31B is not particularly limited. The thickness of the inner layer 31B may be, for example, 10 μm or more and 1000 μm or less.

The thickness ratio between the outer layer 31A and the inner layer 31B is not particularly limited as long as it does not impair the effects of the present invention.

The peel strength between the first coating film 21 and the second coating film 31 is preferably 0.1 N/10 mm or more and 4 N/10 mm or less in accordance with "General coating test methods - Part 5 - Section 6: Adhesion (cross-cut method)" as specified in JIS K-5600-5-6. This allows both adhesion and peelability between the first coating film 21 and the second coating film 31 to be achieved. The lower limit of the peel strength is preferably 0.3 N/10 mm, and more preferably 0.5 N/10 mm. By setting the lower limit of the peel strength to the above value, the adhesion between the first coating film 21 and the second coating film 31 can be improved. The upper limit of the peel strength is preferably 3 N/10 mm, and more preferably 2 N/10 mm. By setting the upper limit of the peel strength to the above value, the peelability of the second coating film 31 from the first coating film 21 can be more reliably expressed.

When peeling the second coating film 31 from the first coating film 21, it is preferable that the second coating film 31 can be peeled continuously at the interface K with the first coating film 21. Specifically, for example, when the end of the second coating film 31 to be peeled is pinched and the second coating film 31 is peeled along the peeling direction at a speed of 10 cm/sec to 10 m/sec, it is preferable that the second coating film 31 can be peeled continuously from the first coating film 21 without being torn. This allows the second coating film 31 to be peeled smoothly without excessive effort.

Next, we will explain how to form the painted part 101 of the vehicle 1.

First, a metal structure 11 formed into a predetermined shape is prepared, and then a first coating film 21 and a second coating film 31 are formed on the metal structure 11 in that order.

The method for forming the first coating film 21 can be appropriately applied using known techniques depending on its configuration (type, function, etc.).

The method of forming the second coating film 31 is, for example, to apply a composition (without filler particles) containing the polymer (or polymer and crosslinking agent) used to form the resin a2 and a solvent onto the first coating film 21, and heat-curing it at a predetermined temperature for a predetermined time to form the inner layer 31B. Next, a composition containing the polymer (or polymer and crosslinking agent) used to form the resin a1, filler particles b, and a solvent is applied onto the obtained inner layer 31B, and heat-curing it at a predetermined temperature for a predetermined time to form the outer layer 31A. The above temperature and heating time can be appropriately selected depending on the polymer, etc. used to form the second coating film 31.

As described above, the painted portion 101 of the vehicle 1 has the above-mentioned configuration, and therefore can maintain excellent moisture impermeability and appropriate adhesion (adhesion and peelability) for a long period of time. As a result, it is possible to prevent the deterioration of the inner layer 31B of the second paint film 31 from causing a loss of appropriate adhesion with the first paint film 21, and to prevent the first paint film 21 from blisters or stains.

Second Embodiment
Fig. 3 is a schematic cross-sectional view of a paint film showing the second embodiment. As shown in Fig. 3, the painted portion 102 of the vehicle 2 is generally composed of a metal structure 11, a first paint film 22, and a second paint film 32. In this embodiment, the configurations of the first paint film 22 and the second paint film 32 are different from those of the first embodiment. Since the configuration of the metal structure 11 is the same as that of the first embodiment, the same parts are given the same reference numerals and detailed description thereof is omitted. In addition, the configuration other than the configurations of the first paint film 22 and the second paint film 32 shown below, and the method of forming the painted portion 102 are the same as those of the first embodiment.

The first coating film 22 is a coating film provided on the metal structure 11. The second coating film 32 is a coating film provided on the first coating film 22. The second coating film 32 has an inner layer 32B arranged so as to be in contact with the surface s22 of the first coating film 22, and an outer layer 32A arranged on the opposite side of the inner layer 32B to the first coating film 22. The outer layer 32A contains resin a1 and filler particles b, and the inner layer 32B contains resin a2 and does not contain filler particles.

The surface s22 (the surface in contact with the inner layer 32B of the second paint film 32) of the first paint film 22 in the painted portion 102 of the vehicle 2 has a step p. The second paint film 32 is layered on the first paint film 22 so as to fill the step p. Specifically, the surface of the inner layer 32B of the second paint film 32 facing the first paint film 22 is formed so as to be in close contact with the surface s22 of the first paint film 22 along the step p. The outer layer 32A of the second paint film 32 is formed on the inner layer 32B so that the surface s32 is flat.

As described above, the painted portion 102 of the vehicle 2 is configured such that the inner layer 32B of the second paint film 32 contains resin a2 but does not contain filler particles. Therefore, even when the second paint film 32 is formed on the first paint film 22 having the step p, the second paint film 32 can be tightly attached without creating a gap between them, and excellent moisture impermeability and appropriate adhesion (adhesion and peelability) can be maintained for a long period of time.

That is, thermal strain occurs near the step p due to the temperature difference between day and night, but the inner layer 32B, which does not contain filler particles, is in contact with the interface K. Because the inner layer 32B is a coating film made of resin a2, it can deform to eliminate the thermal strain, and no peeling or cracks occur in the second coating film 32 at the interface K. Therefore, even on the surface of the vehicle 2 with the step p (surface s22 of the first coating film 22), the first coating film 22 and the second coating film 32 adhere to each other, forming a highly reliable coating part 102.

The present invention is not limited to the configuration of the above-described embodiment, but is intended to include all modifications within the scope of the claims and meaning equivalent to the claims.

For example, in the first and second embodiments described above, the second paint film 31, 32 is exemplified as being composed of two layers, an outer layer 31A, 32A and an inner layer 31B, 32B. However, the second paint film of the vehicle only needs to have a specific inner layer arranged so as to be in contact with the surface of the first paint film, and a specific outer layer arranged on the opposite side of the first paint film with the inner layer in between. That is, although not shown, for example, the second paint film may have one or more other layers between the inner layer and the outer layer. Also, the second paint film may have another layer arranged on the opposite side of the inner layer with the outer layer in between.

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

<Preparation of painting part>
The materials used in the examples and comparative examples are shown below.
[A] Metal structure (A-1) Metal material: aluminum alloy (A5052), thickness: 3 mm, surface shape: flat (no steps)
[B] First coating film (B-1) Solution-based paint Fluoropolymer paint (manufactured by Nippon Paint Co., Ltd.)
[C] Second coating film (C-1) Acrylic copolymer emulsion (alkyl acrylic acid ester) (manufactured by Rinrei Co., Ltd., model number: PA-2)
(C-2) Filler particles: plate-like mica particles (Kinsei Matec Co., Ltd., average particle size 60 μm)
(C-3) Solvent: distilled water

[Example 1]
The solution-based paint (B-1) was applied onto a metal material (A-1) as a metal structure, and the coating was heated at 50° C. to form a first coating film having a thickness of 50 μm.
Next, a composition containing 0.4 parts by mass of acrylic copolymer emulsion C-1 and 0.6 parts by mass of solvent C-3 was applied onto the first coating film, and then heat-treated at 80°C for 10 minutes to form an inner layer having a thickness of 250 µm.
Next, a composition containing 0.4 parts by mass of acrylic copolymer emulsion C-1, 0.4 parts by mass of filler particles C-2, and 0.6 parts by mass of solvent C-3 was applied onto the inner layer, and then heat-treated at 80° C. for 10 minutes to form an outer layer having a thickness of 250 μm (the inner layer and outer layer constitute a second coating film), thereby obtaining Example 1 (see FIG. 1 ).

[Comparative Example 1]
A composition (without filler particles) containing 0.4 parts by mass of acrylic copolymer emulsion C-1 and 0.6 parts by mass of solvent C-3 was applied onto the first coating film formed in the same manner as in Example 1, and then heat-treated at 80°C for 10 minutes to prepare a coating film having a thickness of 500 μm (see coating film 3100 in Figure 4), thereby obtaining Comparative Example 1.

[Comparative Example 2]
A composition containing 0.4 parts by mass of acrylic copolymer emulsion C-1, 0.2 parts by mass of filler particles C-2, and 0.6 parts by mass of solvent C-3 was applied onto a first coating film formed in the same manner as in Example 1, and then heat-treated at 80°C for 10 minutes to prepare a coating film having a thickness of 500 μm (see coating film 3200 in Figure 5), thereby obtaining Comparative Example 2.

<Evaluation>
The moisture impermeability and adhesion (adhesion and peelability) were evaluated, and the results are shown in FIG. 6 and FIG.

[Water impermeability]
For each of Example 1 and Comparative Examples 1 and 2, an accelerated test was performed by exposing the samples to an environment of 60° C. temperature and 90% humidity for 100 hours, and then the moisture permeability was measured in accordance with the moisture permeability test method (cup method) for moisture-proof packaging materials specified in JIS Z0208, and the measured value was used as an index of moisture impermeability.
As shown in FIG. 6, the relative moisture permeability of the embodiment was smaller by 30% than that of Comparative Example 1 and by about 10% than that of Comparative Example 2, and the moisture impermeability was good.

[Adhesion strength (adhesion and peelability)]
For each of Example 1 and Comparative Example 2, an accelerated test similar to the accelerated test for [moisture impermeability] was conducted, and then a 180° peel test was conducted by the adhesive tape peeling method in accordance with the adhesion test (cross-cut method) specified in JIS-K5600, and the measured value (peel strength) was used as an index of adhesion.
7, Example 1 had a relative peel strength 30% greater than Comparative Example 2, and better adhesion was obtained than Comparative Example 2. Furthermore, the peel strength of Example 1 was 0.97 N/10 mm, and when the second coating film was peeled off from the first coating film at a speed of 10 cm/sec to 10 m/sec along the peeling direction, the second coating film could be peeled off continuously from the first coating film without tearing, and good removability was obtained.

Reference Signs List 1, 2 Vehicle 11 Metal structure 21, 22 First paint film 31, 32 Second paint film 31A, 32A Outer layer 31B, 32B Inner layer 101, 102 Painted portion a1, a2 Resin b Filler particle

Claims (5)

A vehicle having a painted part on its surface,
The coating section includes:
A metal structure;
a first coating film provided on the metal structure;
a second coating film provided on the first coating film;
The second coating film is formed so as to be continuously peeled off at the interface with the first coating film,
The second coating film has an inner layer arranged so as to be in contact with a surface of the first coating film, and an outer layer arranged on the opposite side of the first coating film with the inner layer interposed therebetween,
the outer layer includes a first resin and filler particles, the filler particles being mica;
The vehicle, wherein the inner layer contains a second resin and does not contain filler particles. 2. The vehicle according to claim 1,
A vehicle, wherein the concentration of the filler particles in the outer layer is 1% by mass or more and 50% by mass or less. 2. The vehicle according to claim 1,
A vehicle in which the peel strength between the first paint film and the second paint film is 0.1 N/10 mm or more and 4 N/10 mm or less. 2. The vehicle according to claim 1,
The first resin and the second resin are the same or different resins that are cured using an acrylic copolymer. 2. The vehicle according to claim 1 ,
The filler particles include particles having a long side of 0.1 μm or more and 1000 μm or less and a short side of 1/10 or less of the long side.