JPH07117172A - Emboss decorative steel sheet coated by polyethylene resin - Google Patents

Abstract

PURPOSE:To improve the characteristics, such as an adhesive property of a film, embossing property, workability, and resistance to heat, by a method wherein the surface of a metallic sheet is coated by two kinds or more of different polyethylene resins, made up mainly of polyethylene through an adhesive agent and embossed on the outermost layer. CONSTITUTION:A surface-treated steel sheet is a cold-rolled steel sheet, for example, the surface of which chemically treated by the plating of Zn, Ni, Cr, Al, Cu proper or alloy plating and/or composite plating containing these metals or by chromate treatment or the like. An adhesive layer, made up mainly of polyester or polyethylene resin of dry thickness of 2-20mum, is formed on the steel sheet. An emboss steel sheet coated by polyethylene resin coating, consisting of a polyethylene resin constituent constituted of 40-80wt% of medium density polyethylene, 2-20wt% of high density polythylene and the balance of one kind or more of low density polyethylene resin, polypropylene resin, acrylic resin, vinyl resin and the like, a pigment and an adder upon forming the film, is adhered onto the adhesive layer.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polyethylene resin-coated embossed decorative steel sheet having excellent embossing properties.

[0002]

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

It is mainly used as a decorative steel sheet for home appliances and interiors, but a polyvinyl chloride-coated steel sheet deteriorates the working environment due to plasticizer, hydrochloric acid, etc. generated by heating at the time of manufacture, and burns to the atmosphere. It causes pollution. Polyester is expensive and has poor embossing properties. Polypropylene, like polyester, is expensive and inferior in embossability.

Among them, polyethylene is attracting attention because it is inexpensive and the gas generated during combustion is relatively environmentally friendly.

When a polyethylene film is coated on a steel sheet, low density polyethylene is considered for most of them. However, although it has excellent adhesiveness with a steel sheet, it has not been put to practical use because of its large thermal change in embossing property. Therefore, there is a demand for a decorative steel sheet which is inexpensive, has excellent adhesion to a steel sheet and embossing property, and is environmentally friendly.

[0006] For example, as an example, a method of coating a resin on a steel sheet and laminating a polyolefin resin through a modified polyolefin adhesive (Japanese Patent Application No. 59-27098).
Although 8) has been proposed, the embossing property and heat resistance of the olefin resin are 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. 63-2133).
75) has been proposed, but it is not sufficient in terms of economic efficiency and productivity. Although a polyethylene rubber-coated article and a method of irradiating with an electron beam have been proposed, the designability, particularly the embossability, is not sufficient. Thus, various coated steel sheets of polyolefin resin have been proposed, but have not been put into practical use as decorative steel sheets. Therefore, there is a demand for a decorative steel sheet that is inexpensive, has excellent adhesion to a steel sheet, embossability and workability, and is environmentally friendly.

[0007]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned drawbacks by using a polyethylene resin as a main component,
It is to provide a steel sheet having excellent embossability.

[0008]

The decorative steel sheet of the present invention comprises a surface-treated steel sheet having two layers of an adhesive layer having a dry thickness of 2 to 20 μm and a polyethylene resin layer of 50 to 500 μm as an upper layer thereof. Is a decorative steel sheet that has been embossed.

The present invention will be described in detail below.

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 containing these metals, composite plating or chromate treatment,
A chemical conversion treatment such as a phosphate treatment is included. 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 generally Zn, Sn, Al,
0.5 to 50 g / m ² for Cr plating, Cr, N
0.01-5 g / m ^{2 for} i-plating, and 0.1 for chemical conversion treatment.
01-3 g / m ² is applied.

The above-mentioned surface-treated steel sheet further comprises chromic acid, silicic acid, or a salt thereof in addition to one or more of epoxy, polyester, and acrylic resins having thermosetting properties.
0.1 or more of alumina and phosphate to resin
A composition containing a solution containing 3% by weight as a main component may be applied as a solid content in an amount of 0.1 to 30 g / m ² .

Next, before coating the surface-treated steel sheet with a polyethylene resin, an adhesive is applied on the steel sheet or on the surface layer of the polyethylene resin. The appropriate thickness is 2 to 20 μm. If it is 2 μm or less, no effect is recognized, and if it is 20 μm or more, the effect is saturated and it is not economical.

Polyester or olefin adhesives are suitable as the adhesive used in the present invention. Many are distributed.

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

The embossability is inferior only with a medium density polyethylene resin. The embossability is improved by adding high-density polyethylene. On the other hand, if the amount is 20 parts by weight or more, the embossing property, particularly the adhesiveness, is deteriorated. The low-density polyethylene alone is extremely inferior in embossability. When at least one of low density polyethylene, polypropylene, acrylic, polyester, epoxy, rubber and vinyl is added as the balance, the adhesion and embossability with the steel sheet are further improved.

The surface of the polyethylene-based resin layer (appearance when coated) may be hard-coated in order to improve the scratch resistance. In that case, a urethane-based, polyester-based, acrylic-based resin or the like is applied.

The surface layer of the steel sheet coated with polyethylene resin is embossed. As one method, 1
It can be obtained by heating to 50 to 250 ° C., press-bonding with a roll having an arbitrary embossed pattern to 5 to 100 kg / cm, and immediately cooling.

[0019]

【Example】

Example 1 A 0.5 mm mild steel plate was plated with 20 g / m ² of Zn and further treated with 0.015 g / m ² chromate of Cr, followed by a primer treatment of epoxy 1: polyester 5: chromate 0.1. 01: A water-soluble paint composed of silica 0.03 was applied so as to have a dry thickness of 3 μm, and heat treatment was performed at 120 ° C. for 20 seconds. Next, 0.
An adhesive in which a polyethylene powder having a particle size of 1 to 10 μm is dispersed using a modified polyester resin as a binder is applied to a dry thickness of 5 μm, and after heating at 200 ° C. for 30 seconds, 70% by weight of acrylic acid-modified medium density polyethylene,
High density polyethylene 5% by weight and low density polyethylene 25
50μm film consisting of wt% is laminated and 150 ℃
After heating, the embossing roll having surface gloss of 60 degrees and gloss of 0.5 was pressure-bonded 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: # girder is inserted into the steel plate of the present invention at a depth reaching the steel plate with a cutter knife, and Erichsen 8 mm is placed in the # girder part.
Was projected, and the degree of peeling was evaluated. Embossing property: Surface gloss finished with an embossing roll showing gloss of 0.5 at 60 degree gloss was judged by a gloss meter and the naked eye (the more glossy, the worse the embossing property). Surface condition after embossing: After the steel plate after embossing was kept in an electric oven at 120 ° C. for 2 hours, the surface was compared and judged with a gloss meter and the naked eye, and those having no change were regarded as good. Tables 1 to 4 show the conditions for producing the steel sheet of the present invention, and Tables 5 to 8 show the results of evaluation of film adhesion and embossing property.

[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 polyethylene-based resin-coated embossed decorative steel sheet of the present invention is a decorative steel sheet having excellent adhesion and embossing property with the steel sheet, and can be widely used for home appliances and interiors.

Claims (1)

[Claims] 1. A surface-treated steel sheet having a dry thickness of 2 to 2
Medium-density polyethylene 40 to 8 with an adhesive layer containing 0 μm polyester-based or polyethylene-based resin as a main component
0% by weight and 2 to 20% by weight of high-density polyethylene, or at least one of low-density polyethylene-based, polypropylene-based, acrylic-based, vinyl-based, polyester-based, epoxy-based, and rubber-based resins, and pigments and film formation Embossed decorative steel sheet coated with polyethylene resin containing the above additives.