JP3014574B2 - Embossed decorative steel sheet coated with polyethylene 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 polyethylene resin-coated embossed decorative steel sheet having excellent embossability.

[0002]

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

[0003] Its application is mainly used as decorative steel sheet for home appliances and interiors. However, polyvinyl chloride coated steel sheet deteriorates the working environment due to plasticizer, hydrochloric acid, etc. generated by heating at the time of manufacturing, and burns to the atmosphere due to combustion. May cause contamination. Polyester is expensive and has poor embossability. Polypropylene is also expensive and inferior in embossability like polyester.

[0004] Among them, attention has been paid to polyethylene, which is inexpensive and whose gas generated during combustion is relatively environmentally friendly.

[0005] When a polyethylene film is coated on a steel sheet, low-density polyethylene is mostly studied. However, although it has excellent adhesion to a steel sheet, it has not been put to practical use because of a large thermal change in embossability. 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.

For example, as an example, a method of coating a steel sheet with a resin and laminating a polyolefin resin via a modified polyolefin adhesive (Japanese Patent Application No. 59-27098)
8) has been proposed, but the embossability and heat resistance of the olefin resin are not sufficient. Further, 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. 63-2133).
75) has been proposed, but it 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. Accordingly, there is a demand for an environmentally friendly decorative steel sheet which is inexpensive, has excellent adhesion to steel sheets, excellent embossability and workability, and is environmentally friendly.

[0007]

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

[0008]

The decorative steel sheet according to the present invention comprises a surface-treated steel sheet having an adhesive layer having a dry thickness of 2 to 20 .mu.m and a polyethylene resin layer having a thickness of 50 to 500 .mu.m on the adhesive layer. Is an embossed decorative steel sheet.

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,
Chemical conversion treatment such as phosphate treatment is included. Of course, the front and back of the steel sheet may have different surface treatments.

Although the amount of plating or the amount of chemical conversion film is not particularly limited, it is generally Zn, Sn, Al,
0.5 to 50 g / m ^{2 for} Cu plating, etc.
0.01 to 5 g / m ^{2 for} i-plating, and 0.1 to 5 g / m ² for chemical conversion treatment.
01 to 3 g / m ² are applied.

[0012] The above-mentioned surface-treated steel sheet is obtained by adding chromic acid, silicic acid or a salt thereof to one or more of epoxy, polyester and acrylic resins having thermosetting properties.
One or more of alumina and phosphate are used in an amount of 0.1 to
In some cases, a composition containing a solution containing 3% by weight as a main component is applied as a solid content of 0.1 to 30 g / m ² .

Next, prior to coating the surface-treated steel sheet with a polyethylene resin, an adhesive is applied to the steel sheet or to the surface layer of the polyethylene resin. Its thickness is suitably from 2 to 20 μm. When the thickness is 2 μm or less, no effect is observed.

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

Next, the polyethylene resin serving as the outermost layer contains a medium density of 40 to 80% by weight, a high density of 2 to 20% by weight, and the balance is low density polyethylene, polypropylene, acrylic, vinyl, or the like. A layer having a thickness of 50 to 500 μm containing at least one of polyester, epoxy, and rubber.

The embossing property is inferior if only a medium density polyethylene resin is used. Embossability is improved by adding high density polyethylene. On the other hand, when the content is more than 20 parts by weight, the embossing property, in particular, the adhesion is reduced. Low-density polyethylene alone has significantly poor embossability. 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 (appearance when coated) 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 polyethylene resin is embossed. One way is to
It can be obtained by heating to 50 to 250 [deg.] C., pressing with a roll having an arbitrary embossed pattern at 5 to 100 kg / cm, and immediately cooling.

[0019]

【Example】

Example 1 A 0.5 mm mild steel sheet was plated with Zn at 20 g / m ² , and further subjected to a chromate treatment of 0.015 g / m ² as Cr. 01: A water-soluble paint composed of 0.03 silica was applied so as to have a dry thickness of 3 μm, and was subjected to a heat treatment at 120 ° C. × 20 seconds. Next, 0.
An adhesive in which polyethylene powder having a particle size of 1 to 10 μm is dispersed with a modified polyester resin as a binder is applied to a dry thickness of 5 μm, heated at 200 ° C. for 30 seconds, and then 70% by weight of acrylic acid-modified medium density polyethylene,
5% by weight of high density polyethylene and 25 of low density polyethylene
A 50 μm film consisting of 50% by weight is laminated at 150 ° C.
And pressed with an embossing roll having a surface gloss of 60 ° gloss and a gloss of 0.5 at 50 kg / cm and immediately cooled with water to produce a steel sheet of the present invention. The steel sheet of the present invention was evaluated for adhesion, workability and embossability with the steel sheet by the following methods. Coating adhesion: The steel plate of the present invention is inserted with a # knife to the depth reaching the steel plate with a cutter knife, and the Erichsen 8 mm is inserted in the # column.
Was stretched out, and the degree of peeling was evaluated. Embossing property: The surface gloss finished with an embossing roll having a gloss of 0.5 at 60 ° gloss was determined with a gloss meter and the naked eye (the more glossy, the worse the embossing property). Surface state after embossing: After the steel sheet after embossing 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 the one with no change was regarded as good. Tables 1 to 4 show conditions for producing the steel sheet of the present invention, and Tables 5 to 8 show evaluation results of film adhesion and embossability.

[0020]

[Table 1]

[0021]

[Table 2]

[0022]

[Table 3]

[0023]

[Table 4]

[0024]

[Table 5]

[0025]

[Table 6]

[0026]

[Table 7]

[0027]

[Table 8]

[0028]

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

Continuation of front page (56) References JP-A-59-68319 (JP, A) JP-A-3-237144 (JP, A) JP-A-4-336113 (JP, A) (58) Fields studied (Int .Cl. ⁷ , DB name) B32B 15/08 103 B32B 7/12

Claims (1)

(57) [Claims] Claims 1. A surface-treated steel sheet has a dry thickness of 2 to 2 mm.
An adhesive layer mainly composed of a polyester-based or polyethylene-based resin having a thickness of 0 μm, and a medium-density polyethylene having a polyethylene-based resin component having a thickness of 50 to 500 μm as an upper layer.
0% by weight and 2 to 20% by weight of high-density polyethylene, or at least one or more of low-density polyethylene, polypropylene, acrylic, vinyl, polyester, epoxy, and rubber-based resins, and the remainder when forming pigments and films Embossed decorative steel sheet coated with a polyethylene-based resin, comprising: