JP3091081B2 - Embossed decorative steel sheet coated with polyolefin resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyolefin resin-coated embossed decorative steel sheet having excellent embossability.

[0002]

2. Description of the Related Art In recent years, as a resin-coated decorative steel sheet, many steel sheets coated with a film of polyvinyl chloride, polyester or the like have been used.

[0003] Its use is mainly used as decorative steel sheets for home appliances and interiors. However, polyvinyl chloride coated steel sheets deteriorate the working environment due to plasticizers, chlorine and the like generated by heating during production, and burn due to combustion. May cause contamination. Polyester is expensive and has poor embossability.

[0004] Among them, polyolefin resins, which are inexpensive and whose gas generated during combustion is relatively environmentally friendly, have attracted attention.

[0005] When a polyethylene film is coated on a steel sheet, most of it is simply a laminate of a low-density transparent or colored film, but there is no decorative steel sheet intended for embossing. When a colored film is used, addition of an expensive pigment causes poor economic efficiency.

For example, as one example, a method has been proposed in which a steel sheet is coated with a resin containing a large amount of rust-preventive pigment, and a colored polyolefin resin is laminated via a modified polyolefin-based adhesive (Japanese Patent Application No. 59-270988). However, the embossability of the olefin resin is not sufficient. In addition, a method comprising four layers of an epoxy resin layer, a modified polyethylene resin layer, a polyethylene resin layer, and a top coating resin layer (Japanese Patent Application No.
3-213375) has been proposed, but is not sufficient in terms of economy and productivity. Methods coated with polyethylene rubber and methods of irradiating with an electron beam have also been proposed, but their design properties, especially embossability, are not sufficient. As described above, various coated steel sheets of a polyolefin resin have been proposed, but have not been put to practical use as decorative steel sheets. Therefore, there is a demand for a decorative steel sheet which is inexpensive, has excellent adhesion to steel sheets and embossability, and is environmentally friendly.

[0007]

SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned drawbacks and to provide a steel sheet having a polyolefin resin as a main component and having excellent embossability.

[0008]

The decorative steel sheet according to the present invention comprises a surface-treated steel sheet, a colored layer having a dry thickness of 2 to 40 μm, or an adhesive layer of 1 to 10 μm, and a transparent or translucent layer formed on the adhesive layer. This is an embossed decorative steel sheet comprising two or three layers of a polyolefin resin layer of 10 to 500 μm.

Hereinafter, the present invention will be described in detail.

The surface-treated steel sheet used in the present invention is a cold-rolled steel sheet having a thickness of 0.1 to 2.0 mm.
Ni, Cr, Al, Cu alone or alloy plating, composite plating or chromate treatment containing these metals,
A chemical conversion treatment such as a phosphate treatment and a coating type chemical conversion treatment are included. In addition, these surface treatments may be combined. Of course, the front and back of the steel sheet may have different surface treatments.

The amount of plating or the amount of chemical conversion film is not particularly limited, but is generally Zn, Sn, A
1, 0.5 to 50 g / m ^{2 for} Cu plating, etc.
r, the Ni plating 0.01-5 g / m ^2, the chemical conversion treatment is applied 0.01 to 3 g / m ^2.

In the above-mentioned coating type chemical conversion treatment, chromic acid, silicic acid or a salt thereof, alumina,
A composition containing, as a main component, a solution containing 0.1 to 3% by weight of one or more phosphates with respect to the resin is used as a solid content of 0.1 to 3%.
0 g / m ² may be applied.

Next, before coating the surface-treated steel sheet with a polyolefin-based resin,
The colored paint is coated with 2 to 40 μm. When the thickness is 2 μm or less, no effect as a colored layer is observed, and the embossing property is remarkably inferior when the thickness of the polyolefin resin film laminated on the upper layer is as thin as 10 μm.
If it is 40 μm or more, the effect as a colored layer is saturated, and the economic efficiency is poor. The coloring layer may be a paint type or a film type. However, the hardness of the coloring layer is in the range of 3B to 2H in pencil hardness in any of the types, and the embossing property is inferior for those outside this range.

Next, the polyolefin-based resin film does not require an adhesive layer if the adhesive strength is sufficient without the use of an adhesive layer, but an adhesive layer of 1 to 10 μm is required if the adhesiveness is poor. . In that case, the adhesive is applied to the surface of the polyolefin resin film or the surface of the colored layer.

As the adhesive used in the present invention, a polyester-based or olefin-based adhesive is suitable. Many are distributed.

Next, the outermost layer contains a polyethylene resin, a polypropylene resin or a medium resin having a medium density of 40 to 80% by weight and a high density of 2 to 20% by weight. This is a layer having a thickness of 10 to 500 μm containing at least one of a resin, a vinyl, a polyester, an epoxy and a rubber.

Next, after the outermost layer of the polyolefin-based resin is laminated on the surface of the colored layer, it is embossed. The embossing is performed by thermocompression bonding using an embossing roll, and any embossing roll having an uneven pattern or a mirror-finished surface is used. When a mirror-finished roll is used, the polyolefin-based resin-coated steel sheet has an appearance with excellent sharpness.

The temperature at the time of embossing is suitably 100 to 140 ° C. in the case of polyethylene. The temperature is 140 to 200 ° C. in the case of polypropylene, and 100 to 200 ° C. in the case of a mixture of polyethylene and polypropylene.

In the case of an olefin resin, the heating temperature at the time of embossing is 100 to 1 with only a medium density polyethylene resin.
It is 20 ° C, and at 130 ° C, the embossing disappears.
When high-density polyethylene is added, the emboss does not disappear even at 130 ° C. When 20% by weight or more of the high-density polyethylene resin is added, the adhesiveness tends to decrease. When at least one of low-density polyethylene, polypropylene, acrylic, polyester, epoxy, rubber, and vinyl is added as the balance, the adhesion to steel sheets and the embossability are further improved.

The surface of the polyethylene resin layer may be subjected to a hard coating treatment in order to improve the scratch resistance.
In that case, a urethane-based, polyester-based, acrylic-based resin, or the like is used.

The surface layer of the steel sheet coated with the polyolefin resin is embossed as described above. As one of the methods, it is heated to 150 to 250 ° C. and pressure-bonded with a roll having an arbitrary embossed pattern by 5 to 100 kg / cm.
It can be obtained by cooling immediately. When a roll having a mirror surface is used, an appearance having sharpness can be obtained.

[0022]

【Example】

Example 1 A 0.5 mm mild steel plate was plated with Zn at 20 g / m ² , and further subjected to a chromate treatment of 0.015 g / m ² as Cr. Next, after applying a colored polyester-based paint at a dry thickness of 20 μm and heating at 220 ° C. for 40 seconds, a 100 μm polyethylene resin film previously subjected to corona discharge treatment was laminated and heated to 130 ° C. ,
An embossing roll having a surface gloss of 60 ° gloss and exhibiting 0.5 was pressed at 50 kg / cm and immediately cooled with water to produce a steel sheet of the present invention. Example 2 10 g / m ² of Zn-2% Co was added to a 0.5 mm mild steel sheet.
Plating was performed, and as a coating-type chemical conversion treatment, a water-soluble paint composed of epoxy 1: polyester 5: chromate 0.01: silica 0.03 was applied at a dry weight of 1 g / m ² ,
A heat treatment was performed at 20 ° C. × 20 seconds. Next, the colored paint is applied at a dry thickness of 20 μm, heated at 220 ° C. for 40 seconds, cooled in the air, and a modified polyethylene powder having a particle size of 0.1 to 10 μm binds the modified polyester resin to the binder. The adhesive dispersed as 2 μm in dry thickness
After applying and heating at 210 ° C. for 35 seconds, a translucent 150
After laminating an olefin film mainly containing medium-density polyethylene having a thickness of μm and heating it to 140 ° C., the emboss is pressed at 50 kg / cm using a surface gloss of 0.5 at 60 ° gloss. And immediately cooled with water to produce a steel sheet of the present invention. After cleaning the surface of the steel sheet 0.6mm which are Zn plated Example _{^{3 90g / m 2, Zn 3}} (PO 4) 2 4H 2 O as 0.9 g /
m ² zinc phosphate treatment. Next, the colored paint is applied at a dry thickness of 15 μm, and heated at 220 ° C. for 40 seconds. Then, an adhesive in which polyethylene powder having a particle diameter of 0.1 to 10 μm is dispersed in advance using a modified polyester resin as a binder is applied. After laminating a 1 μm coated and dried polyethylene-based film and heating to 140 ° C., use embossing rolls having a surface gloss of 60 ° gloss and exhibiting 0.5, pressing at 50 kg / cm and immediately cooling with water. And
A steel sheet of the present invention was prepared. The steel sheet of the present invention was evaluated for adhesion, workability and embossability by the following methods. Film adhesion: A 5 mm wide # girder was inserted into the steel plate of the present invention with a cutter knife at a depth reaching the steel plate, and an Erichsen 8 mm overhang was made on the # girder portion to evaluate the degree of peeling. Embossability: Measured at 60 ° gloss using a digital variable-angle gloss meter manufactured by Suga Test Instruments Co., Ltd., and judged visually. Surface state after embossing: After the steel sheet of the present invention was aged for 2 hours in an electric oven at 120 ° C., the surface was compared and judged with a gloss meter and the naked eye, and a sheet having no change was evaluated as good. Tables 1 to 5 show conditions for producing the steel sheet of the present invention, and Tables 6 to 9 show evaluation results of film adhesion and embossability.

[0023]

[Table 1]

[0024]

[Table 2]

[0025]

[Table 3]

[0026]

[Table 4]

[0027]

[Table 5]

[0028]

[Table 6]

[0029]

[Table 7] ：: No peeling of polyolefin film

[0030]

[Table 8]

[0031]

[Table 9]

[0032]

The embossed steel sheet coated with a polyolefin resin according to the present invention is a decorative steel sheet having excellent adhesion to a steel sheet and embossability, and can be widely used for home appliances and interiors.

──────────────────────────────────────────────────の Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B32B 15/08 103 B29C 59/04

Claims (4)

(57) [Claims] 1. A dry steel sheet having a dry thickness of 2 to 4
0 μm colored layer, and the upper layer
m, a polyolefin-based resin-coated embossed steel sheet coated with a resin layer obtained by mixing a transparent or translucent polyethylene-based resin and a polypropylene-based resin. 2. A dry thickness of 2 to 4 is applied to the surface-treated steel sheet.
0 μm colored layer, and the upper layer
m, a resin obtained by mixing 40 to 80% by weight of a medium-density polyethylene and 2 to 20% by weight of a high-density polyethylene in a transparent or translucent polyethylene-based resin component, or a low-density polyethylene, a polypropylene, an acrylic, A polyolefin resin-coated embossed decorative steel sheet coated with a resin layer obtained by mixing at least one of vinyl-based, polyester-based, epoxy-based, and rubber-based resins. 3. A dry thickness of 2 to 4 on a surface-treated steel sheet.
A colored layer of 0 μm is coated, and the upper layer is coated with a polyester or polyolefin resin as a main component.
μm of an adhesive layer, and furthermore, a further 10 to 50
A polyolefin resin-coated embossed decorative steel sheet coated with a resin layer of a mixture of a 0 μm transparent or translucent polyethylene resin and a polypropylene resin. 4. A dry thickness of 2 to 4 on a surface-treated steel sheet.
A colored layer of 0 μm is coated, and the upper layer is coated with a polyester or polyolefin resin as a main component.
μm of an adhesive layer, and furthermore, a further 10 to 50
0 μm, a transparent or translucent polyethylene resin component which is a mixture of 40 to 80% by weight of medium density polyethylene and 2 to 20% by weight of high density polyethylene, or low density polyethylene, polypropylene, acrylic, A polyolefin resin-coated embossed decorative steel sheet coated with a resin layer obtained by mixing at least one of vinyl-based, polyester-based, epoxy-based, and rubber-based resins.