JPH0747636A - Production of sharp laminated steel panel - Google Patents

Abstract

PURPOSE:To enhance the sharpness of a laminated steeel panel produced by laminating a plasticized polyvinyl chloride resin film and a biaxially stretched polyethylene terephthalate film through an adhesive layer so that the former film is positioned on the side of a steel panel. CONSTITUTION:After a laminated film consisting of a plasticized polyvinyl chloride resin film and a biaxially stretched polyethylene terephthalate film is laminated to a steel panel, the steel panel is reheated to the temp. range from the melting temp. of the former film to below the melting temp. of the latter film to smooth the former film by the thermal shrinkage of the latter film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a laminated film of a plasticized polyvinyl chloride resin film-biaxially stretched polyethylene terephthalate film and laminates the former film on the adhesive layer side. The present invention relates to a method for producing a reflective laminated steel sheet.

[0002]

2. Description of the Related Art In the field of home electric appliances, a pre-coated steel sheet is used for the exterior instead of self-painting to save labor during manufacturing. However, depending on the equipment, a laminated steel sheet may be used. A typical example of this laminated steel sheet is a laminated film of a plasticized polyvinyl chloride resin film (hereinafter referred to as a PVC film) and a polyethylene terephthalate film (hereinafter referred to as a PET film), which is a PVC film on the adhesive layer side. Laminated to become. Here, as the PET film of the laminated film,
Biaxially stretched ones are usually used.

In this steel sheet, an adhesive agent is applied to the steel sheet and heated in an oven. Then, when the temperature of the steel sheet is 170 to 180 ° C., the laminated film is laminated with a rubber laminator roll to attach the PVC film to the adhesive agent. It was manufactured by a method of laminating so as to be on the layer side. However, this method requires P at the time of lamination.
Since it is not a method of melting and adhering the VC film,
The unevenness of the PVC film appears on the surface of the PET film,
The skin becomes orange and the appearance with high image clarity cannot be obtained.

Therefore, in order to improve the yuzu skin, after laminating the laminated film, the laminated film is pressed with a heating type mirror surface metal roll to melt only the PVC film having a low melting point, and the PET film surface is A smoothing method has been proposed (Japanese Patent Laid-Open No. 63-280627). However, in this method, the pressure applied to the laminated film with the metal roll is short and the PVC film is difficult to melt.
The unevenness of the T film was difficult to completely disappear. Also, since the skin of the metal roll is transferred to the PET film,
When foreign matter such as dust or dust adheres to the film, there is a problem that the PET film is depressed due to the depression and the appearance is impaired. In particular, since the PET film is easily charged, foreign matter is likely to adhere to the PET film, and the occurrence of depressions is unavoidable. Further, there is a problem in that when the pressure applied by the roll is changed, the image clarity is different, and a uniform appearance cannot be obtained.

[0005]

Therefore, in the present invention, P
It is intended to provide a method for producing a clear image-laminated steel sheet which completely eliminates the unevenness of the ET film and has no depression.

[0006]

DISCLOSURE OF THE INVENTION According to the present invention, after laminating a laminated film, a biaxially stretched polyethylene terephthalate film having a temperature above the melting temperature of a plasticized polyvinyl chloride resin film is prepared by a heating method in which a heat source does not come into contact with the laminated film. The steel sheet was reheated below the melting temperature of the film.

[0007]

The PET film is biaxially stretched and is heated in a non-contact manner. Therefore, when the PET film is heated to a temperature below the melting temperature, thermal contraction occurs and the contraction tension causes the P film to melt.
The surface of the VC film can be smoothed. This P
The smoothing of the PVC film by the ET film is performed by heating the steel sheet at a melt viscosity of the PVC film of 5 × 10 ⁴ Pa.
If the temperature is as low as s or more, the heating is not sufficiently performed. Therefore, it is preferable to raise the heating temperature of the steel sheet so that the melt viscosity is less than 5 × 10 ⁴ Pa.s.

In the conventional method of pressing the laminated film with the heating type mirror surface metal roll, the laminated film is also heated, so that the PET film is also heated. In this case, the PET film is also heated.
The film is pressed by the roll, and the PVC film is melted only for a short time while being pressed by the roll, so that heat shrinkage does not occur and the shrinkage tension of the PET film causes The smoothing function does not work. Therefore, the smoothing of the laminated film is performed only by the mirror surface skin transfer action of the roll.

The method of reheating the steel sheet by a heating method in which the heat source does not come into contact with the laminated film is not particularly limited, but a method of passing through a hot air oven or an induction heating oven, lamination of steel sheets It is possible to use a method in which a plurality of heating rolls are arranged on the side opposite to the film laminate side, and the rolls are passed while supporting the opposite side of the steel sheet.

The laminated steel sheet according to the present invention is produced by forming an adhesive layer on the steel sheet, laminating the laminated film with a laminator roll after heating, and then reheating. In forming the adhesive layer, a pretreatment such as degreasing treatment or chemical conversion treatment is usually performed before forming the adhesive layer, but this may be omitted depending on the surface properties of the steel sheet. In addition, a primer layer may be formed after the pretreatment and before the formation of the adhesive layer in order to improve the adhesion and the corrosion resistance. If desired, a rust preventive pigment, a coloring pigment, an extender pigment or the like may be added to this primer layer. The steel sheet may be a cold rolled steel sheet, a galvanized steel sheet, an aluminum plated steel sheet, a composite plated steel sheet, a stainless steel sheet, or the like.

As the adhesive, one used for laminating a PVC film on a steel plate can be used. The adhesive is not particularly limited as long as it can bond the PVC film even if it is a one-component type or a two-component type, and may be, for example, an acrylic type adhesive, a polyester type adhesive, or a polyurethane type adhesive. Further, a rust preventive pigment, a coloring pigment, an extender pigment or the like may be added to the adhesive.

[0012] As the PVC film of the laminated film,
A vinyl chloride resin composition comprising a polyvinyl chloride resin, a plasticizer, a stabilizer, a pigment, and other additives (for example, an ultraviolet absorber) formed into a film by a calendaring method or an extrusion method. as,
Monomers copolymerizable with vinyl chloride homopolymers and vinyl chloride monomers such as vinyl acetate and ethylene.
However, the plasticizer, stabilizer, pigment, etc. are not particularly limited. On the other hand, the PET film is biaxially stretched and transparent. The thickness of these films is preferably about 50 to 200 μm for a PVC film and about 10 to 50 μm for a PET film.

The laminated film may be printed with a pattern for enhancing the design. In this printing, either PVC film or PET film is patterned by gravure printing, and then the printed surface is laminated on the other film with an adhesive so that the patterned pattern exists in the laminated film. The printing ink may be acrylic-based, polyester-based, polyurethane-based base resin mixed with a pigment or various additives.

The lamination of the laminated film to the steel plate is P
Although the VC film is on the adhesive layer side, it is preferable that the laminated film side is made of rubber for the laminator roll. This is because, when made of metal, a depression is generated due to the foreign matter being pushed in as described above. It is preferable that the temperature of the steel sheet during the lamination is about 20 ° C. lower than the temperature at which the melt viscosity of the PVC film is 1 × 10 ⁵ Pa.s. When the temperature is higher than this temperature, the viscosity of the PVC film becomes too low, so that the surface shape of the laminar roll is transferred, or a dent easily occurs due to a foreign substance attached to the surface of the roll.

[0015]

【Example】

(1) Preparation of laminated film Ba-Zn was added to 100 parts by weight of polyvinyl chloride resin.
3 parts by weight of a system stabilizer, 2 parts by weight of epoxidized soybean oil, 5 parts by weight of TiO ₂ and a predetermined colorant, and a plasticizer (D
OP) was mixed in a predetermined amount shown in Table 1 and then kneaded with a test roll at a predetermined temperature shown in Table 1 for 10 minutes to produce PVC films having various thicknesses. Table 1 shows the temperatures 20 ° C. lower than the temperatures at which the melt viscosity of this PVC film is 5 × 10 ⁴ Pa.s and 1 × 10 ⁶ Pa.s. Next, PET films of various thicknesses shown in Table 1 [Lumira-S manufactured by Toray Industries, Inc.]
Type and T type], a two-pack type polyester adhesive was applied so as to have a dry thickness of 3 μm, baked at 180 ° C., and laminated on the PVC film by a roll.

In Table 1, laminated films Nos. 1, 3 and 5 were patterned by gravure printing on the PVC film side before lamination, and Nos. 2, 4 and 6 were reversed on the PET film side. Was similarly applied. Moreover, the melting temperature of the S type and T type of PET film is 251 each.
And 249 ° C.

[0017]

[Table 1] (Note 1) The melt viscosity of PVC film is 5 × 10 ⁴ Pa.s
The temperature at which (Note 2) The melt viscosity of PVC film is 1 × 10 ⁶ Pa.s
20 ° C lower than the temperature at which

(2) Manufacture of laminated steel sheet Electrogalvanized steel sheet (weight per unit surface: 20 g / m ² , plate thickness: 0.
4 mm) is applied with a coating type chromate treatment to apply a phenoxy resin-based primer to a dry thickness of 5 μm, and then a two-pack type polyester adhesive is applied on the primer layer to a dry thickness. 5 μm was applied and baked so that the maximum reached steel plate temperature was 200 ° C., and immediately the laminated film of Table 1 was applied to the adhesive layer side with the laminated film of Table 1 using a laminator roll made of silicone rubber. Then, the steel sheet was reheated to the temperature shown in Table 2 by a hot air oven of the conveyor type.

Next, the laminae produced as described above
Using the image sharpness measuring device,
And NSIC * were measured. The measured values are shown in Table 2. In addition, NSIC shows a feeling of yuzu skin, and NSIC * shows a feeling of blurring, both of which are expressed in%, and the larger the value, the higher the sharpness. Also, high image clarity means an NSIC value of about 70 or more, N
The SIC * value is 60 or more.

[0020]

[Table 2] (Note) There is no dent in either case.

[0021]

[Comparative Example] Table 3 shows the steel sheet temperature during reheating in Examples.
Outside the present invention as shown in FIG.
C * was measured. The measured values are shown in Table 3.

[0022]

[Table 3] (Note) Laminate roll; surface roughness of metal roll is 1.
The rubber roll has a thickness of 5 μm and is made of silicone rubber.

[0023]

As described above, since the reheating in the present invention heats the steel sheet by a heating method in which the heat source does not contact the laminated film, the heating time is longer than that in the case of heating with a metal roll, Moreover, it is a heating method capable of supplying sufficient heat to the steel sheet. Therefore, the PVC film can be melted sufficiently and P
The unevenness can be completely eliminated by the heat shrinkage of the ET film. In addition, no depression is generated due to the pushing of foreign matter. In addition, P melted by heat shrinkage of the PET film
Since the VC film is made smooth, the image clarity is uniform.

Claims (2)

[Claims] 1. A steel sheet is coated with an adhesive and heated, and then a laminated film of a plasticized polyvinyl chloride resin film and a biaxially stretched polyethylene terephthalate film is laminated on the laminated plastic film by a laminator roll. In the method for producing a laminated steel sheet in which the resin film is laminated so as to be on the adhesive layer side, after laminating the laminated film, a heating method in which the heat source does not contact the laminated film A method for producing a clear image-laminated steel sheet, which comprises reheating the steel sheet to a temperature above the melting temperature and below the melting temperature of the biaxially stretched polyethylene terephthalate film. 2. The image clarity laminate according to claim 1, wherein the steel sheet is reheated to a temperature at which the melt viscosity of the plasticized polyvinyl chloride resin film becomes less than 5 × 10 ⁴ Pa.s. Steel plate manufacturing method.