JPH04246478A - Article coated in deep color - Google Patents

Abstract

PURPOSE:To obtain an article coated in deep color and having a high near- infrared-reflecting capability by forming a near-infrared-reflecting surface on the coated surface of the article and forming thereon a deeply colored coating film which absorbs visible light but transmits near infrared rays. CONSTITUTION:A near-infrared-reflecting surface, reflecting pref. 80% or higher of near infrared rays, is formed on the coated surface of an article (e.g. a metal or a plastic plate) and a deeply colored coating film is formed thereon, pref. in a thickness of 80mum or lower. Deep color realized here includes black, dark grey, dark blue, and dark green each of a color value of 4 or lower. An example of a black colorant used as a main or auxiliary one is a perylene-based org. Black pigment of the formula. Since the coating film transmits near infrared rays well, the article has a high near-infrared-reflecting capability.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to dark-colored painted objects.

0002

2. Description of the Related Art An example of a dark-colored painted object is the body of an automobile. In the case of automobile bodies, dark colors such as black or dark blue are applied (usually through a base film) to the metal plate surface (surface to be painted) or plastic plate surface (surface to be painted) that makes up the car body. A colored coating film is provided. In the case of a dark-colored paint film, for example, a black paint film, it is formed by applying a paint containing carbon black, which is a black pigment.

0003

[Problems to be Solved by the Invention] However, the above-mentioned dark-colored painted objects had the following problems. In conventional dark-colored painted objects, the dark-colored paint film absorbs not only visible light but also near-infrared light in sunlight. The absorption of visible light is useful because a dark color appears when visible light is absorbed, but even if near-infrared light is absorbed, it simply turns into heat and does not cause a dark color. Absorption of near-infrared light is actually harmful, rather than being related to its development. The proportion of near-infrared light energy in the total energy of sunlight is quite high, about 50%, and therefore, the amount of thermal energy generated in the dark-colored paint film due to the absorbed near-infrared light is considerable. the result,
The temperature of the dark-colored paint film itself and the internal temperature of the car body on which the dark-colored paint film is installed increases, causing the dark-colored paint film to deteriorate.
This results in the inconvenience of an increased cooling load.

[0004] In view of the above-mentioned circumstances, an object of the present invention is to provide a dark-colored painted product that is highly reflective of near-infrared light.

[0005]

[Means for Solving the Problems] In order to solve the above problems, the dark-colored painted object according to the present invention is provided with a near-infrared light reflecting surface on the surface of the object to be painted, which absorbs visible light but absorbs visible light. A dark-colored paint film that transmits near-infrared light is provided on the reflective surface. Near-infrared light in this invention refers to light in the wavelength range of 780 to 2500 nm.

[0006] The dark colors developed in dark-colored painted objects include black, dark gray, dark blue, and dark green with a lightness of 4 or less. Specific structural examples of the dark-colored painted article of the present invention include the following. The first type, as shown in FIG. 1, is a form in which a dark-colored coating film 2 is provided directly on the near-infrared light reflecting surface of the surface of the object 1 to be painted.

Second, as shown in FIG. 2, a dark-colored coating film 2 is provided directly on the near-infrared light reflecting surface of the surface of the object 1 to be coated.
Furthermore, a clear film (transparent paint film) 3 is placed on top of the dark color paint film 2.
It is a layered structure. Thirdly, as shown in FIG. 3, a base film (for example, a white paint film) 4 with a high reflectance of near-infrared light is first provided on the surface of the object to be coated 1 with a low reflectance of near-infrared light, and then In this configuration, a dark color paint film 2 is provided on the surface, and a clear film 3 is further laminated thereon.

It goes without saying that the dark-colored painted article of the present invention is not limited to the first to third embodiments described above. For dark paint films such as black, dark gray, dark blue, and dark green with a brightness of 4 or less, a coloring pigment containing black pigment as the main pigment is used in the case of black or dark gray. or dark green, a colored pigment is used, which is a combination of green and blue toning pigments with an appropriate amount of black pigment added. In addition to black, it is essential to add a black pigment to produce dark gray, dark blue, and dark green colors with low brightness. In the case of this invention, the essential black pigment (hereinafter referred to as "main black pigment" as appropriate) has good near-infrared light transmittance (transmits near-infrared light without absorbing it)
It is a pigment. Examples of such main black pigments include perylene organic black pigments and azo organic black pigments.

More specifically, peryogen black (PA
LIOGEN BLACK L0084 (manufactured by BASF).

0010

[Chemical formula 1]

[0011] Also, as the azo organic black pigment, Chromofine Black A-110 of the following chemical formula (Chemical formula 2) is used.
3 (manufactured by Dainichiseika Co., Ltd.).

0012

[Case 2]

[0013] However, R1, R2, R3 in the above formula
is a hydrogen atom, a halogen atom, a methyl group, a methoxy group, an ethoxy group, a methoxycarbonyl group or an ethoxycarbonyl group, X is a -CONH- or -NHCO- group, and Y is an atomic group forming a benzocarbazole ring. be. In the case of dark blue and dark green, blue pigments, green pigments, etc. are used together as toning pigments, but these toning pigments do not show good transparency to near-infrared light and do not absorb it. Since some pigments exhibit brightness, we use pigments for toning that exhibit good reflectivity against near-infrared light (hereinafter referred to as "glitter pigments").
It is preferable to suppress the increase in near-infrared light absorption of the dark-colored paint film. Examples of bright pigments include titanium white (white type), Ti-Zn-Ni-Co fired composite oxide (green type - Dainichiseika Co., Ltd. Dipyroxide Green),
Examples include Co--Al calcined composite oxide (blue type - Dipyroxide Blue manufactured by Dainichiseika Co., Ltd.). In addition, yellow lead (yellow type) or the like can also be used as a bright pigment for toning. Unlike absorbing pigments, glitter pigments can be added in large amounts, so even dark colors can be easily adjusted.

The pigment content of the dark painted film is usually about 3 to 30% by weight based on the total weight (100% by weight) of the film. If the amount is too small, it will be difficult to provide a sufficiently deep color, and if it is too large, it will be difficult to ensure near-infrared light transmittance, and the gloss of the coating film will decrease. The dark-colored paint film may contain an ultraviolet absorber or an antioxidant to improve weather resistance. Of course, ultraviolet absorbers and antioxidants are used that do not impair appropriate dark color development or good near-infrared light transmittance in the dark-colored paint film. Specifically, examples of the ultraviolet absorber include ultrafine zinc oxide particles, bendotrisol compounds, and the like, and examples of the antioxidant include hindered amine compounds, hindered phenol compounds, and the like. It is usually added and used at the paint stage.

When a protective clear film is laminated, the ultraviolet absorber and antioxidant may be included in the clear film, or may be included in both the dark color paint film and the clear film. Good too. Regarding the degree of near-infrared light transmittance of the dark-colored paint film itself, the near-infrared light reflectance r when measured as follows is 80% or more, more preferably 85%.
% or more is preferable.

The spectral reflectance R(
λ) is measured using a white reference plate made of primary barium sulfate powder as a reference. Then, the near-infrared reflectance r is calculated by applying the measured spectral reflectance R(λ) to the following formula (Equation 1).

In measuring the spectral reflectance R(λ), the measurement light is irradiated at an angle of 7° to the normal to the measurement surface of the sample attached to the integrating sphere. This measurement method is generally known as diffuse reflectance measurement. An example of a spectrophotometer that can be used to measure the spectral reflectance R(λ) is a spectrophotometer UV3100 manufactured by Shimadzu Corporation.

The above-mentioned sample for near-infrared light reflectance measurement uses the same dark-colored paint film provided on the dark-colored painted object of the present invention as a near-infrared light reflectance of 95 to 98%. It is provided on a reflective surface (for example, the surface of an aluminum plate). The spectral reflectance R (λ) of the dark-colored paint film surface of this sample was measured as described above, and the near-infrared light reflectance r was determined using the following formula, and this value was 8
It is sufficient that it is 0% (near-infrared light reflectance r80%) or more, more preferably 85% (near-infrared light reflectance r85%) or more.

The amount of reflected near-infrared light is proportional to the degree of near-infrared light transmittance of the dark-colored paint film (the larger the amount of reflected light, the better the transmittance). This allows the degree of transparency to be appropriately defined.

[0020]

[Math 1]

S(λ) in the above formula (Equation 1) is the sunlight spectral irradiation intensity [AM(1.5)]. In addition, AM (
1.5) means ASTM Global AM1.5
Spectral irradiance data
It is. The thickness of the dark paint film is usually 10 μm or more, 3
It is in the range of 0 μm or less. If it is too thin, it will be difficult to achieve sufficient coloring with an appropriate pigment content or to ensure the necessary film strength, and if it is too thick, it will be difficult to ensure sufficient near-infrared light transmittance. In addition, the thickness of the clear film is usually 3~
It is about 10 μm.

The near-infrared light reflecting surface on which the dark-colored paint film is provided has a near-infrared light reflectance r of 8 as measured as described above.
A suitable content is 5%, more preferably 90% or more. Specific examples of near-infrared light reflecting surfaces include the following. The first is the metal surface. Examples include the surface of a metal base material such as an aluminum base material, an iron base material, a tin base material, and the surface of a metal plating film. Specifically, the surface of a metal part of an automobile body is exemplified.

The second is the surface of the plastic base material. For example, the surface of urethane-based, vinyl chloride-based, styrene-based, or epoxy-based resin base materials (plastic sheets, plastic plates, etc.) that have increased reflectance of near-infrared light by blending titanium white, aluminum scale powder, etc. Can be mentioned. Again, the surface of a resin portion of an automobile body is exemplified. The third is the surface of the paint film. Examples include coating film surfaces formed using urethane-based, vinyl chloride-based, styrene-based, and epoxy-based paints that have enhanced near-infrared light reflectivity by blending titanium white, aluminum scale powder, and the like. of course,
In this case, it goes without saying that the coating film itself on which the dark-colored coating film is to be laminated is provided on some kind of base material.

[0024] The degree of near-infrared light reflectivity of the dark-colored painted product of the present invention is determined by the degree of near-infrared light transmittance of the dark-colored paint film and the near-infrared light of the near-infrared light reflecting surface. It is desired that the near-infrared light reflectance r measured as described above is 80%, more preferably 85% or more.

[0025]

[Operation] The dark-colored coated object according to the present invention has excellent near-infrared light reflectivity. This is because the dark-colored paint film has good near-infrared light transmittance, so most of the incident near-infrared light is not absorbed by the dark-colored paint film and is reflected by reaching the near-infrared light reflecting surface. This is because the reflected near-infrared light is then emitted without being absorbed by the dark-colored paint film. Of course, dark painted items,
Appropriate deep color develops. This is because dark-colored paint films absorb visible light.

Therefore, in the dark-colored coated article of the present invention, the problem of temperature rise of the dark-colored coated film and the dark-colored coated article is solved. In contrast, conventionally, carbon black has been used as a black pigment, and since carbon black absorbs near-infrared light very well, dark-colored painted objects using carbon black have poor near-infrared light reflectivity. It was extremely bad, and a noticeable temperature rise occurred in the dark-colored paint film and the dark-colored painted object.

[0027] The near-infrared light reflectance of the near-infrared light reflecting surface is 85%.
If the above is favorable, or if the thickness of the dark-colored paint film is 30 μm or less, the amount of near-infrared light absorbed by the object to be coated will be reduced, and the reflectivity for near-infrared light will be more sufficient. becomes. Since the protective clear film on the dark-colored paint film is transparent, it does not interfere with the development of the dark color and serves to prevent the underlying dark-colored paint film from being damaged.

[0028]

[Examples] Examples, reference examples, and comparative examples of dark-colored coated products according to the present invention will be described below. The dark-colored coated objects of Examples, Reference Examples, and Comparative Examples each have a coated object and a dark-colored coated film (and clear film) as shown in Tables 1 and 2, respectively. However, the objects to be painted, the dark-colored paint film, and the clear film are as follows.

-Object to be painted- Object to be painted■ Alkyd melamine coating film (thickness: 30 μm) containing 30% by weight of titanium white (TiO2).
...The near-infrared light reflecting surface is the paint film surface. Object to be painted ■ Two-component urethane paint film containing 30% by weight of titanium white (thickness 30 μm)...The near-infrared light reflecting surface is the paint film surface.

Object to be painted ■ 20 pieces of aluminum scale powder
Alkyd melamine paint film (thickness 30% by weight) containing
μm)...The near-infrared light reflecting surface is the coating film surface. Object to be painted ■ Vinyl chloride resin plate (thickness 2 mm) containing 10% by weight of titanium white...The near-infrared light reflecting surface is the surface of the plastic base material. Object to be painted ■ Aluminum plate (JIS H 4000
Equivalent product (thickness: 1 mm) ...The near-infrared light reflecting surface is a metal surface.

Object to be painted ■ Alkyd melamine black coating film (thickness 30 μm) containing 5% by weight of carbon black (MA100 manufactured by Mitsubishi Carbon Co., Ltd.) Note that the near-infrared light reflecting surface of the objects to be painted (■ to ■) above Near-infrared light reflectance r
are shown in Table 3. -Dark Paint Film- Dark Paint Film A Alkyd melamine black paint film containing 5% by weight of Paliogen Black Dark Paint Film B Dark paint film C Palio Alkyd melamine black paint film dark color paint film D containing 20% by weight of Genblack Alkyd melamine black paint film containing 33% by weight Palyogen Black Dark color paint film E 20% by weight Palyogen Black, 5 weight% Dipyroxide Green % containing alkyd melamine dark blue paint film (thickness 25μm) Dark color paint film F Alkyd melamine black paint film containing 20% by weight Palyogen Black and 5% by weight ultrafine zinc oxide particles (ultraviolet absorber) (thickness 25μm) Dark paint film G
20% by weight of Chromofine Black A-1103
Alkyd melamine black paint film containing dark paint film H
Carbon black (MA1 manufactured by Mitsubishi Carbon Co., Ltd.)
00) Alkyd melamine black paint film containing 5% by weight - Clear film - Clear film Alkyd melamine transparent paint film containing 10% by weight ultrafine zinc oxide particles (ultraviolet absorber) (thickness 5μ
m)

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

[Table 3]

Table 4 shows the total reflectance rt, near-infrared reflectance r, and brightness of the dark-colored painted objects of Examples, Reference Examples, and Comparative Examples.
It is shown in Table 5. Note that the total reflectance was measured in the same manner as in the measurement of the near-infrared light reflectance r, except that the measurement wavelength range was 260 to 2500 nm and the following formula (Equation 2) was used.

[0036]

[Math 2]

[0037] Tables 4 and 5 also show the measurement results of the surface temperature under conditions of outdoor exposure during sunny weather in summer. The environmental temperature at the time of surface temperature measurement was 32.5°C, and the measurement time was 2:00 pm.

[0038]

[Table 4]

[0039]

[Table 5]

It can be clearly seen that all of the dark-colored painted objects of the examples have high near-infrared light reflectivity, and that increases in surface temperature can be suppressed. In Comparative Example 1, which is a conventional dark-colored painted product, the black pigment is carbon black, so the near-infrared reflectance of the dark-colored painted film is extremely low, and the surface temperature is extremely high. Comparing the near-infrared light reflectances of Examples 3 and 13 and Reference Example 1, we can see that the dark paint films of Examples 3 and 13 (that is, the black pigments Paliogen Black and Chromofine Black A- 1103) has excellent transmittance to near-infrared light.

[0041]

[Effects of the Invention] As described above, in the dark-colored painted object according to the present invention, the near-infrared light transmittance of the dark-colored paint film provided on the near-infrared light reflecting surface is good. Therefore, it is highly reflective of near-infrared light. The dark-colored painted article according to claim 2 has a good near-infrared light reflectance of the near-infrared light reflecting surface, so that the near-infrared light reflectivity is more sufficient.

[0042] In the dark-colored coated article according to the third aspect, since the dark-colored coating film has good transmittance to near-infrared light, near-infrared light reflectivity is more sufficient. In the dark-colored painted object according to claim 4, since the clear film is laminated, the dark-colored painted film is not easily damaged.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing a specific example of the structure of a dark-colored painted article of the present invention.

FIG. 2 is a schematic cross-sectional view showing a specific example of the structure of the dark-colored painted article of the present invention.

FIG. 3 is a schematic cross-sectional view showing a specific example of the structure of the dark-colored painted article of the present invention.

[Explanation of symbols]

1 Object to be painted 2 Dark paint film 3 Clear film 4 Base film

Claims (4)

[Claims] Claim 1: A near-infrared light reflecting surface is provided on the surface of the object to be painted, and a dark-colored paint film that absorbs visible light but transmits near-infrared light is provided on the reflective surface. A dark painted object. 2. The dark-colored painted article according to claim 1, wherein the near-infrared reflectance of the reflective surface is 80% or more. 3. The dark-colored painted product according to claim 1 or 2, wherein the thickness of the dark-colored painted film is 30 μm or less. 4. The dark-colored painted product according to claim 1, wherein a clear film is laminated on the dark-colored painted film.