JP2003340958A - Metallic appearance metal band having excellent wiping workability and appearance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metallic metal band for stabilizing wiping workability and metallic appearance. <P>SOLUTION: The metallic appearance metal band comprises a steel sheet, and a thermoplastic resin film containing an aluminum powder of 5 to 50 mass% and having a thickness of 6 to 25 μm and laminated on at least one side surface of the steel sheet. In this band, the content of the aluminum powder having a particle size of exceeding 30 μm is less than 2 mass%, and the powder contains flaky particles of 75 mass% or more having a thickness of 0.1 to 2 μm and a particle size of 5 to 30 μm. 80% or more of the aluminum powder having a particle size exceeding 10 μm of the contained powder desirably has a parallelism within 10° to the surface of the thermoplastic resin film. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal strip for obtaining an ironing can having a stable glossy appearance by using a metal strip having a thermoplastic resin film laminated on at least one surface thereof.

[0002]

2. Description of the Related Art For beverage containers, ironing cans are widely used because they are easy to mass produce at low cost. In order to ensure ironing workability in these cans, it is common to use a tin-plated steel plate or an aluminum steel plate and apply a lubricant to the surface while ironing, but to prevent external rust and ensure internal corrosion resistance. Since it is necessary to coat with iron after ironing, there is a problem that after molding, a low productivity process of removing the lubricant with a detergent such as an alkali, chemical conversion treatment, and painting is required for each can after molding. . As a technique for improving productivity by omitting the low productivity process for each can, a method of previously laminating resin films on both sides of a metal band or coating with a resin-based paint before processing has been proposed in the past. It was

On the other hand, to secure the design on the outer surface of the can,
There was a problem in the conventional technology. This tendency is particularly remarkable in the case of steel plates among metal strips. General ironing can (DI
In the case of tins, there is a problem that even if tin plating is applied, the whiteness of the outer surface side is lower in the case of steel plates than in the case of aluminum plates, and the image clarity when designed is inferior. It was As a technology for improving the design of the outer surface of a can, a can made by forming a steel sheet laminated with a PET film colored in advance in white is generally known. There is a problem that the conversion rate tends to be different in the can height direction, and the whiteness is likely to be uneven. Further, in recent years, metallic appearance has become preferred, and ironing cans with a metallic appearance having a coating film containing a metal powder on the outer surface of the can have been studied, but only by adding a metal powder. However, unevenness in gloss and difference in color tone are likely to occur due to the difference in thinning rate, and it is difficult to stabilize the design and mass-produce it stably.

[0004]

DISCLOSURE OF THE INVENTION As a result of intensive studies to solve the above problems, the present inventors have defined the shape and existence form of aluminum powder contained in a thermoplastic resin film. The inventors have found that ironing workability and appearance are stable, and have reached the present invention. The outline of the invention will be described below.

[0005]

The main points of the present invention are as follows. The metal strip of the present invention comprises: (1) A thermoplastic resin film containing 5 to 50% by mass of aluminum powder and having a thickness of 6 to 25 μm is laminated on at least one surface of a steel plate, and the aluminum powder has a content rate of more than 30 μm. Is less than 2% by mass, and contains 75% by mass or more of scale-like particles having a thickness of 0.1 to 2 μm and a particle diameter of 5 to 30 μm, and is excellent in ironing processability and appearance. Appearance metal strip. (2) Among the aluminum powder contained, 80% or more of the aluminum powder having a particle size of more than 10 μm has a parallelism of 10 degrees or less with respect to the surface of the thermoplastic resin film. The metal strip has a metallic appearance and is excellent in the described ironing workability and appearance.

[0006]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below with reference to the drawings. First, the metal strip of the present invention will be described. FIG. 1 is a view showing a cross section of a metallic-appearing metal strip which is the basis of the present invention. As shown in this figure, a thermoplastic resin film 2 containing aluminum powder 3 is laminated on the surface of a base material steel plate 1 in the cross section of the metal strip. Further, the plate thickness of the metal strip is not particularly specified, but as a specification suitable for a can application, a plate having a thickness of 0.15 mm to 0.35 mm is often used.

The surface of the metal strip is not particularly limited as long as the adhesiveness to the resin and the ironing processability are ensured. It is desirable to pre-treat the surface with chromic acid, dichromic acid, phosphoric acid, organic acid, etc. in order to secure the same. Examples of applications include aluminum, aluminum alloys, tin-free, chrome-plated steel sheets, nickel-plated steel sheets, phosphoric acid-treated steel sheets, organic phosphoric acid resin-treated steel sheets, tin-plated steel sheets, tin-nickel-plated steel sheets.

The thermoplastic resin is not particularly limited, but polyester, polyamide, polyolefin, etc. can be used. From the viewpoint of heat resistance and cost, polyethylene terephthalate or a mixed resin mainly composed of polyethylene terephthalate, and a copolymer resin mainly composed of a basic structure of ethylene terephthalate are preferable. From the viewpoint of moldability, it is desirable to use a mixed resin containing butylene terephthalate or nylon 6 as a main component, a copolymer resin containing these basic structures as a main component, and the like.

The aluminum powder contained in the thermoplastic resin film is preferably aluminum having a purity of 99.5% or more excluding the surface treatment. Content is 5-50% by mass
Is important. If it is less than 5% by mass, it becomes difficult to secure a stable metallic appearance when the can body is molded. This is because if it exceeds 50% by mass, the effect is saturated in securing the metallic appearance, the cost is increased, and the workability as a film becomes unstable.

Particle size 30 contained in aluminum powder to be contained
Particles of more than μm are less than 2% by mass and have a thickness of 0.1 to
It is important that the scaly particles having a particle size of 2 μm and a particle size of 5 to 30 μm account for 75% by mass or more. If particles with a particle size of more than 30 μm are contained in an amount of more than 2% by mass, they will be the starting points of processing defects during ironing and cause skin defects called galling on the film.

Next, aluminum powder having a prescribed shape and particle size is
It must be contained in an amount of 5 mass% or more. The aluminum powder contains fine particles generated in the process of processing into a scale shape, but if the aluminum powder having the specified shape and particle size is less than 75% by mass, the ironing processability becomes poor and the metallic appearance deteriorates. To do. If the thickness is less than 0.1 μm, it is difficult for the shape to be a flat shape, the metallic feeling is deteriorated, and the appearance is dark and dull.
On the other hand, if the thickness exceeds 2 μm, the surface area of the aluminum powder per unit weight decreases, and the area that can cover and hide the coating decreases, which is disadvantageous in terms of cost. Further, since the weight per particle increases, sedimentation easily occurs when mixed with the resin, which causes a problem.

The particle diameter means the average value of the short diameter and the long diameter when it is assumed to be elliptically shaped. If the particle size is less than 5 μm, the metallic feel is reduced and the appearance is dark and dull. If the particle size exceeds 30 μm, the workability is deteriorated. Large-diameter particles become the starting point of processing defects during ironing and cause skin defects called galling on the film. Further, it is important that the thickness of the thermoplastic resin film containing aluminum powder is 6 to 25 μm. If the thickness is less than 6 μm, the film becomes too thin, causing many troubles in the step of laminating the metal strip, which is unsuitable for industrial production. This is because if it exceeds 25 μm, the ironing workability decreases. The cause of this is not clear,
It seems that the elastic effect of the resin film has a great influence as the thickness increases.

Further, it is desirable that 80% or more of the aluminum powder having a particle size of more than 10 μm among the contained aluminum powder have a parallelism within 10 degrees with respect to the surface of the thermoplastic resin film. When aluminum powder having a large particle size exists at a large angle with respect to the film surface, it often becomes a starting point of a processing defect during ironing molding, and in many cases, skin marks called galling on the film occur during the ironing molding process. The parallelism of the aluminum powder with respect to the film surface can be measured by microscopic observation after polishing the cross section.

[0014]

EXAMPLES Examples of the present invention will be described below. The metallic appearance metal strip was manufactured in the following steps. A metal band is preliminarily heated to a temperature above the melting point of the thermoplastic resin, a thermoplastic resin film containing aluminum powder is pressure bonded to the metal band, and the thermoplastic resin is completely melted and then rapidly cooled in water to prepare. did. Table 1 shows examples and comparative examples. In addition,
As an evaluation method, the appearance was judged by visually observing the body of the can after ironing. Also, the ironing workability is a blank diameter of 142 m.
A m-φ85 cup was molded and redrawn by the body maker and ironed three times to mold a can of φ66.7 mm and height 130 mm.

[0015]

[Table 1]

[0016]

As described above, according to the present invention, it is possible to easily manufacture an ironing can having a metal appearance coating film on the outer surface side of the can and having a stable can gloss appearance after ironing.

[Brief description of drawings]

FIG. 1 is a view showing a cross section of a metallic appearance metallic strip which is the basis of the present invention.

[Explanation of symbols]

1 Base material steel plate 2 Thermoplastic resin film 3 aluminum powder

Continued front page    (72) Inventor Toru Chiyagi             No. 1-1 Tobata-cho, Tobata-ku, Kitakyushu, Fukuoka             Nippon Steel Co., Ltd., Yawata Works (72) Inventor Hirokazu Yokoya             No. 1-1 Tobata-cho, Tobata-ku, Kitakyushu, Fukuoka             Nippon Steel Co., Ltd., Yawata Works F-term (reference) 4F100 AB03A AB10B AB10C AK01B                       AK01C AK07B AK07C AK42B                       AK42C AK46B AK46C BA02                       BA03 BA06 BA10B BA10C                       DE02B DE02C GB16 JB16B                       JB16C JL01 JN24 YY00B                       YY00C                 4J002 BB001 CF061 CF071 CL011                       DA096 FA016 FD096 GF00                       GG01                 4K044 AA02 AB02 BA06 BA10 BA15                       BA17 BA21 BB02 CA31

Claims (2)

[Claims] 1. An aluminum powder 5 to at least one surface of a steel plate.
A thermoplastic resin film containing 50% by mass and having a thickness of 6 to 25 μm is laminated, the content of the aluminum powder having a particle diameter of more than 30 μm is less than 2% by mass, and the thickness is 0.1 to 2
A metallic appearance metallic strip having excellent ironing workability and appearance, characterized by containing 75% by mass or more of flaky particles having a particle diameter of 5 μm and a particle diameter of 5 to 30 μm. 2. The particle diameter of the aluminum powder contained is 10 μm.
The metallic appearance metal strip excellent in ironing workability and appearance according to claim 1, wherein 80% or more of the aluminum powder having a size of more than m has parallelism within 10 degrees with respect to the surface of the thermoplastic resin film. .