JP2000233470A - Pet film laminated steel panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a PET film laminated metal panel having both of matte appearance and pearl appearance and excellent in bending processability and antistaining properties. SOLUTION: A PET film laminated steel panel is obtained by successively laminating a colored resin layer, an adhesive layer, a printing ink layer and a PET film on the surface of a steel panel. In this case, the printing ink layer contains a pearl pigment and the arithmetic mean deviation of profile not being in contact with the adhesive layer of the PET film is set to 0.05-0.5 μm and that of the surface being in contact with the printing ink layer of the PET film is set to 0.02 μm or less. The PET film may contain at least one kind of a pigment among titanium oxide, alumina and silica in its surface not coming into contact with the printing ink layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a PET film-laminated steel sheet having a matte appearance and a pearl appearance, and having excellent bending workability and stain resistance.

[0002]

2. Description of the Related Art A biaxially stretched polyethylene terephthalate resin film (hereinafter referred to as a PET film) has excellent mechanical properties, smoothness, high transparency, chemical resistance, and stain resistance. These are used for applications such as home appliance exterior panels and interior wall materials. The PET film has a higher tensile strength than plasticized polyvinyl chloride resin film, acrylic resin film, polyolefin resin film and the like, and is excellent in printing workability. Because of its print design properties, it is positioned as a high-grade coated steel sheet with a combination of an arbitrary design and a high gloss surface appearance.

[0003] On the other hand, "matte appearance" is preferred for interior wall materials and some home appliance exterior panels. The present inventors have disclosed in
Japanese Patent Publication No. 0-34822 discloses a printed PET film-laminated steel sheet having a deep embossed appearance by adjusting the surface properties of a printing surface and the viscosity of an adhesive.

[0004]

However, this printing PE
With the T film laminated steel sheet, the matte appearance described above cannot be obtained. As a result of examining the mechanism of "matting",
"Image sharpness (sharpness)", which is a measure of reflecting an image like a mirror, depends on the macroscopic smoothness of the surface of the object, that is, the degree of specular reflection in a strict sense, Is not affected by macroscopic irregularities such as embossing,
Microscopic smoothness was found to dominate that value. This indicates that it is not possible to develop microscopic irregularities on the surface of the printed PET film-laminated steel sheet by devising the printing surface provided on the back side of the highly rigid PET film.

[0005] Further, the present inventors have disclosed in Japanese Patent Application No. 10-75049.
By defining the center line average surface roughness of the surface of the PET film-laminated steel sheet that is not in contact with the adhesive layer to 0.05 to 0.5 μm, a matte appearance can be obtained without impairing general characteristics. Proposed that. With a higher level of print design required, a combination with "matte appearance" and "pearl appearance" has come to be required. In order to obtain a “pearly feeling”, various studies were conducted based on the patent application, but none of them exhibited both a “matte appearance” and a “pearl appearance”.

The present invention has been devised in order to solve such a problem. By adjusting the center line average surface roughness of the surface of the PET film which is not in contact with the printing ink layer and the surface which is in contact with the printing ink layer, the gloss is improved. An object of the present invention is to provide a PET film-laminated steel sheet having an erased appearance and a pearl appearance, and having excellent bending workability and stain resistance.

[0007]

Means for Solving the Problems The present invention provides a PET film-laminated steel sheet having a colored resin layer, an adhesive layer, a printing ink layer, and a PET film laminated in this order on the surface of the steel sheet, in order to achieve the object. The center line average surface roughness of the surface of the PET film that is not in contact with the printing ink layer is 0.05 to
0.5 μm, the printing ink layer contains a pearl pigment, and the center line average surface roughness of the surface in contact with the printing ink layer is 0.02 μm.
m or less. A resin layer containing at least one pigment of titanium oxide, alumina, and silica may be provided on the surface of the PET film that is not in contact with the printing ink layer.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The matte appearance depends on the microscopic unevenness of the outermost layer as described above, and can be exhibited by adjusting the surface morphology of the surface of the PET film that is not in contact with the printing ink layer. . That is, the center line average surface roughness of the surface of the PET film that is not in contact with the printing ink layer is 0.05 to
By setting the thickness to 0.5 μm, a matte appearance and bending workability can be imparted. The reason why the center line average surface roughness of the present invention is limited to 0.05 to 0.5 μm is that a matte appearance cannot be obtained if the thickness is less than 0.05 μm, and P
This is because the ET film breaks (film cracks) starting from unevenness during severe molding.

In order to develop a pearl (pearl luster) appearance, the center line average surface roughness of the surface of the PET film in contact with the printing ink layer must be 0.02 μm or less. The pearly feeling is based on the regular arrangement of pearl pigments, and the pearl appearance is not exhibited unless the PET film surface is smooth. Pearl pigments generally used in printing inks are obtained by coating flaky natural mica with a thin film layer of titanium dioxide. The pearl appearance is manifested by the interference of light by aligning the scale surfaces of the scaly pearl pigment. Therefore, if the surface of the PET film on which the printing ink layer is provided is uneven, the scale surface of the pearl pigment also exhibits a disordered direction, no interference light is obtained, and no pearl appearance is exhibited.

As the PET film, not only a general biaxially stretched polyethylene terephthalate resin film but also a copolymer resin film of an acid component of terephthalic acid and isophthalic acid can be used. To facilitate film lamination,
Those having a thickness of 10 to 50 μm are preferred. If the film thickness is less than 10 μm, the workability is poor.
If the thickness exceeds m, the internal stress of the film during bending becomes large, and the film is easily peeled.

As a method for adjusting the center line average surface roughness of the surface of the PET film not in contact with the printing ink layer to 0.05 to 0.5 μm, only the surface of the PET film not in contact with the printing ink layer is sandblasted. For example, a resin layer containing at least one pigment of titanium oxide, alumina, and silica is provided on the surface. The sandblasting may be performed by a known method. For example, carborundum (silicon carbide powder), metal particles, and the like are strongly sprayed on the surface of the PET film together with compressed air, and the object can be achieved by washing and drying. The control of the center line average surface roughness of the PET film by sandblasting can be performed by the particle size of the particles to be sprayed and the processing amount (processing frequency per area). The larger the particle size of the particles, the larger the processing amount. Indeed, the center line average surface roughness of the PET film surface increases.

When a colored resin layer containing at least one pigment of titanium oxide, alumina, and silica is provided on the surface of the PET film, the matrix resin is not particularly limited, but polyester resin, polyurethane resin, acrylic resin, epoxy resin, etc. A resin (for example, ESCA paint: manufactured by Kansai Paint Co., Ltd.) made of an acrylic resin containing a silanol group, an epoxy group, or a hydroxyl group and a metal chelate such as an aluminum chelate can also be used. In addition, 0.01 to 3.0 parts by weight of a polyfluorocarbon chain-containing compound and 0.01 to 3.0 parts by weight of silicone oil are blended with 100 parts by weight of the matrix resin solids to impart non-adhesiveness. You can also.

The center line average surface roughness (resin layer) of the PET film which is not in contact with the printing ink layer can be adjusted by the particle size and the amount of the pigment to be compounded. For example, when 0.5 to 5 parts by weight of a pigment having a particle size of 1 to 10 μm is blended, a “matte appearance” is exhibited. The pigment has a large particle size,
As the blending amount increases, the center line average surface roughness also increases. The surface of the PET film that is in contact with the adhesive layer or the surface where the resin layer is provided is preferably subjected to a corona discharge treatment or an easy adhesion treatment such as coating the surface of the PET film with an acrylic resin or a polyester resin.

The printing ink layer can be provided on a part or the entire surface of the PET film. When a printing ink layer is provided in a part, a printing ink layer containing a pearl pigment,
Printing design is exhibited by a combination of an adhesive layer and a colored resin layer which form the lower layer. When the printing ink layer is provided on the entire surface, a printing ink containing a pearl pigment is used, or a pearl pigment is used in at least one layer when a solid printing layer is provided on the entire surface of a single or multiple pattern printing layers. Can be considered. By combining these with an adhesive layer and a colored resin layer, it is possible to develop a printing design with a matte and pearly feeling.

As the printing ink, one obtained by mixing a pigment and various additives with a base resin such as a vinyl chloride-vinyl acetate copolymer, an acrylic resin, a polyester resin, and a polyurethane resin is used. Further, printing (for example, gravure printing) and drying on a PET film can be repeatedly laminated. The pearl pigment to be mixed with the printing ink is a pigment having a pearl luster, and is composed of natural mica (Al ₂ O ₃ .K ₂ O.Si
In addition to O ₂ ) and fish scales, there are also compounds such as bismuth and lead. Generally, scaly natural mica coated with titanium dioxide in a thin film layer is used.

The colored resin layer is made of a mixture of an epoxy resin, a polyester resin, a polyurethane resin, a linear high-molecular polyester resin, a vinyl chloride resin, a polyolefin resin, and the like, with a coloring pigment, an extender pigment, a rust preventive pigment, and other additives. Used. The colored resin layer may be a single layer or a laminate of a plurality of layers. When the colored resin layer is formed by coating with a paint, the dry coating film thickness is preferably 2 to 20 μm. When the colored resin layer is a resin film, the film thickness is 5 μm.
It is preferably from 0 to 300 μm.

In the case where the colored resin layer is formed by coating a paint, an adhesive for laminating the PET film provided with the printing ink layer and the colored resin layer is a one-component or two-component polyester resin adhesive. And a polyurethane resin-based adhesive. If necessary, a coloring pigment, a rust-preventive pigment, an extender pigment, and the like may be added to the adhesive. The adhesive layer may be provided on a PET film with a printing ink layer provided thereon. Before the colored resin layer is provided on the surface of the steel sheet, a primer layer such as an epoxy resin or a polyester resin may be provided. If necessary, a coloring pigment, a rust-preventive pigment, an extender pigment, or the like may be added to the primer.

When the colored resin layer is a resin film made of a vinyl chloride resin, a polyolefin resin, or the like, a PET film provided with a printing ink layer and a colored resin film are laminated in advance, and the obtained composite film is interposed via an adhesive layer. To be laminated on a steel plate. In this case, the adhesive between the steel sheet and the composite film is also a one-component or two-component polyester resin-based adhesive, a polyurethane resin-based adhesive, and the like. If necessary, a coloring pigment, a rust-preventive pigment, an extender pigment, and the like may be used. It may be added. Before providing the adhesive layer on the surface of the steel sheet, a primer layer made of an epoxy resin, a polyester resin or the like may be provided. The above-mentioned various pigments and the like may be added to the primer as needed.

The steel sheet is prepared by subjecting various types of plated steel sheets such as Zn-plated steel sheets, Zn-Al-plated steel sheets, Al-plated steel sheets, and stainless steel sheets to a pretreatment such as a phosphate treatment and a coating type chromate treatment as required. Is used. When the colored resin layer is formed by coating with a paint, the colored resin paint is applied to a steel sheet by a known coating method such as a roll coating method or a curtain coating method, then dried and baked, and then an adhesive layer is formed in the same manner. Then, a PET film provided with a printing ink layer on its upper surface is laminated and immediately cooled to produce a PET film-laminated steel sheet. When a plurality of colored resin layers are used, painting and drying may be repeated.

A colored resin layer is formed by applying a paint,
When the adhesive layer is provided on the PET film side, a colored resin paint is formed on a steel plate by the above-mentioned known coating method, and then a printing ink layer and an adhesive layer are sequentially provided so that the adhesive layer is in contact with the colored resin layer. The laminated PET film is immediately cooled and a PET film laminated steel sheet is manufactured. The colored resin layer is a resin film, and the P is provided with a printing ink layer.
When laminating a composite film in which an ET film and a colored resin film are laminated in advance on a steel plate via an adhesive layer, after forming an adhesive on the steel plate by the above-described known method, the composite film is laminated on the upper surface thereof, and immediately. After cooling, a PET film laminated steel sheet is manufactured. When a primer layer is provided between the steel sheet and the adhesive layer, the primer layer may be formed in the same manner as the adhesive.

[0021]

Example 1 A hot-dip galvanized steel sheet having a thickness of 0.5 mm and a basis weight per side of 45 g / m2 was subjected to a coating type chromate treatment, and a linear high molecular polyester resin-based ivory paint was dried to a film thickness. Is applied with a bar coater so as to have a thickness of 15 μm, and is heated and dried in an oven for 60 seconds so that the maximum attained plate temperature becomes 230 ° C., and then a two-component polyester resin-based adhesive (curing agent: isocyanate) is dried. And heated and dried in an oven for 60 seconds so that the maximum attained plate temperature was 210 ° C., and immediately thereafter, a printed PET film was laminated on the upper surface and cooled with water.
The printed PET film at this time was a 25 μm thick PET film sandblasted on one side with carborundum (center line average surface roughness: 0.008 μm for the surface in contact with the printing ink layer, and 0 for the surface not in contact with the printing ink layer. .35
μm) and a pearl pigment (scale natural mica coated with titanium dioxide in a thin film layer) is printed with an abstract pattern of a polyurethane resin printing ink.

Example 2 The conditions were the same as in Example 1 except that the printed PET film was as follows. Printing PET
The film was prepared by blending 10% by weight of silica having an average particle size of 3 μm on the surface of a PET film having a thickness of 38 μm, and mixing ESCA paint (manufactured by Kansai Paint Co .; 100 parts by weight of an acrylic resin and a metal chelate resin with a polyfluorocarbon chain). 6 μm of a colored resin layer made of [DS-101 manufactured by Daikin Industries, Ltd.] and 0.2 part by weight of an organically modified silicone oil [SF8428 manufactured by Dow Corning Toray Co., Ltd.] (not in contact with the printing ink layer) Center line average surface roughness of the surface: 0.23 μm) and the opposite surface (center line average surface roughness of the surface in contact with the printing ink layer: 0.007 μm)
A polyurethane resin printing ink containing a pearl pigment is printed with an abstract pattern, and a light ivory polyurethane resin printing ink is solid-printed on the upper surface thereof.

Example 3 SUS43 having a thickness of 0.45 mm
Chromate treatment is applied to a steel sheet, and a phenoxy resin-based primer containing a rust-preventive pigment is applied using a bar coater so as to have a dry film thickness of 5 μm.
Heat and dry at 15 ° C for 40 seconds, then apply a high-molecular polyester resin-based white paint with a bar coater so that the dry film thickness becomes 15 µm, and use an oven so that the maximum attained plate temperature becomes 230 ° C. After heating and drying for 60 seconds, a printed PET film was laminated on the upper surface and cooled with water. At this time, the printed PET film was coated with a two-component polyester resin-based adhesive (curing agent: isocyanate) on the upper surface of the printing ink layer using the same film as in Example 2 so as to have a dry film thickness of 3 μm, and dried. Things.

Example 4: SUS43 having a thickness of 0.45 mm
A steel plate is subjected to a coating type chromate treatment, and a phenoxy resin-based primer containing a rust-preventive pigment is applied by a bar coater so that a dry film thickness becomes 5 μm.
After heating and drying at 15 ° C. for 40 seconds, a two-component polyurethane resin-based adhesive was applied with a bar coater so that the dry film thickness became 5 μm.
The film was dried by heating to 10 ° C. for 60 seconds, a composite film was laminated on the upper surface, and cooled with water. In this case, the composite film used was the same PET film as in Example 1, and the surface provided with the printing ink layer and a dark blue plasticized polyvinyl chloride resin film having a thickness of 100 μm were combined with a one-component polyester resin. It is a film laminated using an adhesive.

COMPARATIVE EXAMPLE 1 A printed PET film was prepared by adding a base PET film (thickness: 25 μm) to an average particle size of 4.2.
The conditions were the same as in Example 1 except that a center line average surface roughness (front and back) of 0.27 μm containing 0.8% by weight of titanium oxide of μm was used. Comparative Example 2: A printed PET film having the same base as that of Example 1 and having a center line average surface roughness of 0.87 μm on a surface not in contact with the printing ink layer and a center line average surface on a surface in contact with the printing ink layer The conditions are the same as in Example 2 except that a surface having a roughness of 0.008 μm is used.

Comparative Example 3 When the printed PET film is PET
Use a film having no colored resin layer on the film surface (center line average surface roughness of the surface in contact with the printing ink layer: 0.00
The conditions are the same as in Example 2 except for the thickness of 7 μm. Comparative Example 4: A printing PET film in which silica was not added to the colored resin layer provided on the surface of the PET film (center line average surface roughness of the surface not in contact with the printing ink layer:
Except for 0.015 μm), the conditions were the same as in Example 2. Comparative Example 5: Composite film having the same base as Comparative Example 1
The conditions are the same as in Example 4 except that an ET film is used.

The appearance, bending workability, and stain resistance of the obtained PET film-laminated steel sheet were examined. As shown in the test results in Table 1, each of the present inventions has excellent characteristics, the matte property has a 60 ° reflection gloss value of 40 or less, and exhibits an appearance having both matte and pearl luster. 180
The bending workability by close contact bending was also good, and it was confirmed that the PET film did not crack. The stain resistance is also good. The oil resistance of the ink stain is as follows. Apply the oil ink to the surface of the PET film-laminated metal plate with a red oil felt pen, let it stand for 24 hours, and then wipe off the oil ink with gauze impregnated with ethanol. I evaluated whether I can do it,
It could be wiped off without a trace. It was found that the comparative PET film-laminated steel sheet could not exhibit matte and pearly feeling, or was poor in bending workability and stain resistance.

[0028]

[Table 1]

[0029]

As described above, the PET film-laminated steel sheet of the present invention has a matte and pearl appearance, and is excellent in bending workability and stain resistance, so there is calmness in the outer panel of home appliances and the interior wall material. It is suitably used for members requiring a heavy texture.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Kenichi Okubo 1st day new steelmaking at 7 Takayashinmachi, Ichikawa-shi, Chiba Coating and Composite Materials Research Dept., R & D Co., Ltd. (72) Inventor Kenji Koshiishi Ichikawa-shi, Chiba Shin-ichi Steel Co., Ltd., 7th Takatani Shinmachi Co., Ltd. Coating and Composite Materials Research Dept., Research Laboratory Co., Ltd. F-term (Reference) 4F100 AA19E AA20E AA21E AB03A AB18 AK01B AK41G AK42D AR00C AR00E BA04 BA05 BA07 BA10A BA10D BA10E CA13E CB00 CC00C DD71E EJ69 GB08 GB48 HB31C JL01 JL06 JL10B YY00D

Claims (2)

[Claims] 1. A PET film-laminated steel sheet having a colored resin layer, an adhesive layer, a printing ink layer, and a biaxially stretched polyethylene terephthalate resin film laminated on a steel sheet surface in this order. The center line average surface roughness of the surface not in contact with the layer is 0.05 to 0.5 μm, the printing ink layer contains a pearl pigment, and the center line average surface roughness of the surface in contact with the printing ink layer is 0.02 μm or less. A PET film laminated steel sheet. 2. The PET film-laminated steel sheet according to claim 1, wherein the biaxially stretched polyethylene terephthalate resin film has a resin layer containing at least one pigment of titanium oxide, alumina and silica on a surface not in contact with the printing ink layer. .