JP2969394B2 - Three-piece can with a multi-layer organic coating on the outer surface of the can - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-piece can manufactured by bonding or welding a can container, in particular, a can body, having at least an outer surface of the can body having a printing ink layer bearing a trademark design and a stretch orientation. The present invention relates to a three-piece can having an organic film having a multilayer structure in which an organic film such as a polyester film layer is laminated.

[0002]

2. Description of the Related Art A can container is viewed from the viewpoint of a can manufacturing process.
It is roughly classified into two types. One is a can with a can bottom integrated with a can body, which is usually wrapped with a canopy, and is usually called a two-piece can. A typical can is a D1 can (Draw and ironing) made by drawing and ironing. lroned
Cans) and DrD cans (Draw
and Reddraw cans). The other is a body with a canopy and a canopy wrapped around it, usually called a three-piece can.Typical cans include solder cans, adhesive cans, and welding cans. Cans are the mainstream.

[0003] As materials for three-piece cans, tin-based materials in which a steel plate is subjected to tin plating and chromate treatment; nickel-plated materials in which a steel plate is subjected to nickel plating and chromate treatment; Tin-free steel materials having a layer coating and the like are used. In most cases, these materials are coated on the inner surface of the can from the viewpoint of content retention (corrosion resistance), and the outer surface of the can is printed with a trademark design to indicate the content.

[0004] Such inner surface coating and outer surface printing are performed by cutting the above-described three-piece can material into a cutting plate, and then applying an inner surface coating (first time), an outer surface printing base coating (second time), and a cutting plate coating line. Manufactured by three passes of external printing (third). For applications that require a high degree of corrosion resistance, two internal coatings may be required, and if the external printing is also multicolor printing of five or more colors, two printings may be required. In some cases, the inner and outer surfaces may be painted and printed by four or five passes. Then, it is necessary to heat the cut plate in a baking furnace each time the plate is passed.

In order to streamline such a coating printing process,
It is expected that the so-called coil coating method will be used to consistently and continuously perform the internal coating and white coating for external printing, and even the external printing, but it is difficult to achieve printing accuracy when using a metal base. , Has not been put to practical use. And the can body joint of the steel plate that has been painted and printed by such many times of cutting plate line passing is left uncoated in the case of, for example, a welded can, and after being cut to the can size It is rolled into a cylindrical shape and welded to form a three-piece can body.

The technique of laminating a film on a steel plate has been around for a long time, and has been studied in the field of cans. For example, as shown in JP-A-62-227642 and JP-A-58-82717, the prior art is mainly used for two-piece cans such as squeezing cans and squeezed ironing cans, 18-liter cans and can lids, There is no technology of a three-piece can in which a film on which a product design is printed is laminated on the outer surface of the can as in the present invention.

[0007]

As described above, in the field of current three-piece cans, in order to reduce the cost of making cans,
Efforts have been made to make the plate coating and printing processes continuous, but only coating has been made continuous, but printing has not been made continuous. On the other hand, there is a demand for a can that is cheaper and more vivid than conventional three-piece cans, has a deep printed appearance, and has excellent design and high designability.

[0008] The painting printing process of three-piece cans is as follows:
Poor productivity, (2) long work-in-progress period, (3) a large number of labors, (4) difficulty in improving the printed finish, (5) difficulty in using ultra-thin materials, etc. There were many problems, which reduced the competitiveness of three-piece cans. The present invention drastically transforms this complicated painting and printing process, and enables painting and printing in a coil shape continuously with one pass of a sheet, and also provides a clearer and deeper printing appearance. An object of the present invention is to provide a can having a high product image and an excellent design.

[0009]

That is, the gist of the present invention is to provide a thermosetting adhesive layer / a printing ink layer for displaying a trademark design / a stretching orientation on a steel sheet surface corresponding to the outer surface of a can from the steel sheet side. Polyester film layer / static friction
Lubricant coating layer with coefficient 0.2 and thickness 0.5 to 4 μm , or thermosetting organic coating layer / thermosetting adhesive layer / printing ink layer displaying trademark design / stretching from steel plate side Oriented polyester film layer / Static friction coefficient 0.2
In, and multiple layers Kangaimen, characterized in that the thickness of a multilayer structure organic film of lubricating coat layer of 0.5~4μm structure
In a three-piece can with an organic coating .

Hereinafter, the present invention will be described in detail. An object of the present invention is to laminate a film on which a trademark design is printed in advance on the surface of a steel plate and obtain a three-piece can manufactured from the steel plate. The reason why the can of the present invention requires the above-mentioned multilayer structure is as follows. First, a polyester film layer having a stretch orientation is used as a carrier for a printing ink layer and a top coat layer. In other words, direct continuous printing on steel sheet is difficult, so continuous printing on film is performed, and continuous printing on steel sheet is indirectly enabled by continuously laminating printed films on the steel sheet surface. It is.

The printing ink layer is for displaying the contents of the can, brand, etc., and for displaying the trademark design. The first purpose of the lubricating film layer is to prevent surface flaws in a high-speed can-making line, but it is also required to ensure appearance such as sharpness. The thermosetting adhesive layer has a sufficient adhesive strength that the pre-printed film is laminated on the entire surface of the can with sufficient adhesive strength, and does not peel off during can manufacturing or heat sterilization after filling the contents. Is to ensure.

The thermosetting organic coating layer is used to secure the sharpness of the printed design. In many cases, a coating containing a white pigment is used, but a coating containing no pigment is used to improve the adhesion. Is sometimes used. The present invention includes a case where the thermosetting organic coating layer is not required. next,
Each layer of the multilayer organic coating layer applied to the can of the present invention will be described.

At present, the mainstream of the three-piece can body is of both the adhesive and the welding type. However, especially in the case of the welding can by the welding method, the welding is performed in an unpainted state, so the repair painting is performed from the viewpoint of the corrosion resistance after the welding. Is required. This repair coating is also in the direction of baking for a short time in terms of productivity, and the maximum temperature may reach 280 ° C. locally. If the melting point of the film is low, the influence of the heat may cause local melting or change of the crystal state, thereby deteriorating the design of the trademark design. Furthermore, after the cylinder is made, the canopy is tightened, the contents are filled, and the ground is rolled. ) Is performed. At this time, if the crystal structure of the resin film changes,
This leads to a reduction in the appearance described above.

In the case of a polyester resin film, a high melting point of about 260 ° C. can be obtained by selecting an alcohol component and an acid component. Since it is possible to secure the same, the applicability is wide and preferable. Even a polyester film having a structure having no orientation has a crystal structure with poor workability or corrosion resistance in a can making process or a filling process and is not practical.

Next, the thickness of the film applied to the present invention will be described. In the present invention, the film thickness is 20 μm
The following applies. If it is less than 5 μm, if the film is scratched in the canning process, it may cause rust spots,
It is not preferable because the appearance is deteriorated. On the other hand, the upper limit is restricted in terms of rust resistance and appearance. In order to ensure the rust resistance of the outer surface of the can, a thicker film is more advantageous,
If the thickness is too large, a step is formed between the film laminated portion and the non-laminated portion (in the vicinity of the welded portion), which may cause a problem such as deterioration of a touch feeling or damage to the film. Therefore, the thickness of the laminated film is 8 to 2
It can be said that the range of 0 μm is preferable.

As the adhesive used in the present invention, it is necessary to select an adhesive which does not cause wrinkling or film peeling by baking or retort treatment of the above-mentioned repair coating, and in this sense, urethane-based, polyester-based, etc. It is necessary to use a thermosetting adhesive. The thickness of the adhesive layer is 0.5 to 4 μm. If it is less than 0.5 μm, the adhesive strength is not sufficiently secured, and if it exceeds 4 μm, the effect is saturated. Preferably it is in the range of 1 to 3 μm.

The outermost lubricating film is a film having a static friction coefficient of 0.2 or less, which is provided from the viewpoint of preventing the film from being damaged in the can making process and passing through the plate.
A material in which Si-based fine particles or an organic lubricant is added to a polyester-based paint or the like is applied. 0.5 ~ 4μ thickness
m. If it is less than 0.5 μm, the coefficient of friction does not decrease and no effect is observed. If it exceeds 4 μm, the effect is saturated without further reduction of the friction coefficient.

The ink layer used in the present invention is for printing a trademark design, and uses an ink having excellent heat resistance and retort resistance using a urethane resin as a main binder. It is determined that gravure printing is preferable from the viewpoint of improving the print appearance, which is an important object of the present invention.
It goes without saying that the thickness of the ink layer varies depending on the design of the trademark and is basically not limited.

In the present invention, there are cases where a thermosetting organic coating layer is required between the steel sheet and the adhesive, and cases where it is not required. When a thermosetting organic coating layer is not required, a four-layer coating consisting of a thermosetting adhesive layer, a printing ink layer for displaying a trademark design, a polyester film layer having a stretch orientation, and a lubricating coating layer from the steel plate side. Become. On the other hand, when a thermosetting organic coating layer is required, the configuration is as follows: from the steel plate side, a thermosetting organic coating layer / thermosetting adhesive layer / printing ink layer for displaying a trademark design / stretch orientation. It has a five-layer film of polyester film layer / lubricating film layer.

The thermosetting organic coating layer referred to in the present invention includes an epoxy coating, an acrylic coating, a polyester coating,
Refers to a resin coating such as a phenolic paint, and is a heat-curable type. As described above, a white pigment such as titanium oxide may be added to the thermosetting organic coating layer in order to ensure sharpness of printing. 1-30% by weight of pigment
Is selected. The thickness of the coating layer containing no white pigment may be 1 to 3 μm, and the thickness of the coating layer containing the white pigment may be 5 to 5 μm.
15 μm.

The steel sheet used in the present invention is made of Al, Cr,
A surface-treated steel sheet plated with Ni, Sn or the like and having a thickness of 0.10 to 0.25 mm is often used. Specifically, after the tin plating coating weight 0.5 to 3.0 g / m ^2, tin-plated steel sheet subjected to chemical conversion treatment, Ni deposition amount 0.3 to 2.0 g / m ²
Nickel-plated steel sheet subjected to a chemical conversion treatment after nickel plating, and Sn and Ni adhesion amounts of 0.5 to 2.0, respectively.
g / m ^2, after plating the 0.1 to 0.5 g / m ² Ni, in the order of Sn, chemical Sn / Ni plated steel sheet subjected to the treatment, a metal chromium coating weight 50~120mg / m ^2, chrome oxide coating weight 5-2
0 mg / m ² of normal TFS (Tin Free Steel
1) a chromium-chromate treated steel plate or the like.

The can of the present invention can be prepared by a dry lamination method in which a film on which a lubricating film is applied and a trademark design is printed in advance is laminated on a steel plate coated with an adhesive, or a lubricating film and a trademark design are applied to the film in advance. After printing, a method of applying an adhesive to the ink layer surface and laminating the dried film on a heated steel plate, etc., can be used to form a steel plate having a multilayer organic film thus obtained into a normal welding can, an adhesive can, etc. Can be made by three-piece can body making means.

Hereinafter, the effects of the present invention will be specifically described with reference to examples.

[0024]

【Example】

Example 1 A 10 μm biaxially stretched polyester film was coated with a 2 μm thermosetting polyester paint containing a silicone lubricant.
m After coating and drying, the opposite side was gravure-printed with a four-color trademark design, and a 1.5 μm urethane-based adhesive was applied on the printing ink and dried. The total thickness of the produced printed film was 16 μm. On the other hand, S of 0.16mm
Sn / N with 1.0 g / m ^{2 of} deposited n and 0.3 g / m ² of deposited Ni
After i-plating, an epoxy ester-based paint containing a white pigment was applied to a chromate-treated steel plate at 5 μm, and when the temperature reached 200 ° C. by induction heating, the printed film was thermocompression-bonded (Sample 1).

Printed film having the same specifications as above
The sample was laminated at 200 ° C. on a steel sheet having an epoxy ester-based coating film containing a 3 μm white pigment (sample 2). In any of the prototype laminated steel sheets, the crystal orientation of the biaxially stretched polyester film remains without any problem,
It had the structure intended by the present invention. From the thus obtained organic laminated steel sheets having a multilayer structure of Sample 1 and Sample 2, 2
A 50ml juice can body is manufactured by welding, the welded part is repair-painted, and the maximum temperature (local temperature of the repair-painted part) is 250.
Dry at ℃.

The can bodies obtained from Samples 1 and 2 had good gloss and no color unevenness, and the sharpness was better than the current three-piece can. The thus obtained can body is subjected to necked-in processing, and further, a canopy is wound around one end, and then the contents are filled, and the ground cover is wound and sealed, followed by retorting at 125 ° C. for 30 minutes. When the appearance change and the adhesion of the film were examined, no change was observed and the film had a good appearance.

Example 2 A 9 μm biaxially stretched polyester film was coated with 1.5 parts of a thermosetting polyester paint containing a silicone lubricant.
After coating and drying, a 6-color trademark design was gravure printed on the opposite surface, and a 2.0 μm urethane-based adhesive was applied and dried on the printing ink. The total thickness of the produced print film was 15.5 μm. Epoxy paint containing no white pigment on the same plated steel sheet as in Example 1 was 6 μm
It was applied and dried, and the above-mentioned film was laminated thereon at 195 ° C. (Sample 3).

The same film was directly laminated at 195 ° C. on the same plated steel sheet as in Example 1 without applying a base coat (Sample 4). As a result of analyzing the polyester resin film structures of Samples 3 and 4 produced as trials, the crystal orientation of the biaxially stretched polyester film remained without any problem, and had the structure intended by the present invention.

From the thus obtained multilayer laminated organic steel sheets of Samples 3 and 4, a 250 ml juice can body was manufactured by welding so that the multilayer structure coating surface became the outer surface of the can, and the weld was repair-painted. It was dried at a maximum temperature of 230 ° C. The obtained can bodies had good gloss and no color unevenness, and the sharpness was better than the current three-piece can. After necked-in processing and further tightening the canopy at one end, filling the contents, sealing and sealing the ground lid, and then retorted at 125 ° C. for 30 minutes. No problem occurred in the adhesion.

Example 3 A nickel-plated steel sheet having a thickness of 0.15 mm was subjected to Ni plating with an adhesion amount of 0.6 g / m ² , and a chromate-treated steel sheet was coated with an epoxy ester paint containing a white pigment of 8 μm, heated and dried. After 8
Cooled to 0 ° C.

On the other hand, a 12 μm biaxially stretched polyester film is coated with 1 μm of a thermosetting polyester paint containing a silicone lubricant, dried, and then 1.8 μm is applied to the opposite surface with a gravure-printed five-color trademark design.
A urethane-based adhesive was applied with a solvent, the solvent was removed, and the adhesive was laminated on the steel sheet surface in a tacky state (Sample 5).

From the thus-obtained multilayer organic coated steel sheet of Sample 5, 2
A 50 ml juice can body was produced by welding, the weld was repaired and dried at a maximum temperature of 250 ° C. The can body obtained from Sample 5 had good gloss, no color unevenness, and sharpness was better than the current three-piece can. After necked-in processing and further tightening the canopy at one end, filling the contents, sealing the ground canopy,
The film appearance and adhesion after retort treatment at 25 ° C. for 30 minutes were also good.

[0033]

The invention guarantees a number of advantages. In other words, by using a special multi-layer structure, continuous coating printing using coil products can be performed at a high speed while maintaining a wide width, and productivity more than twice as high as that of a cutting plate coating line can be secured. it can. Since a large number of line passing operations are not required, the in-process period can be shortened. The use of the coil product also has an advantage that even if the thickness of the material plate becomes extremely thin, no great handling problem occurs. The problems in the conventional painting and printing process for steel plates for three-piece cans, such as labor saving by omitting the process, can be solved at once.

In addition, by employing gravure printing, it is possible to print with sharpness and depth compared to the current external printing cans, and it is possible to supply three-piece cans that meet the diversification and high-grade of consumers. Yes, there is something of great social significance.

Continued on the front page (72) Inventor Tomohiko Hayashi 20-1 Shintomi, Futtsu-shi, Chiba Nippon Steel Corporation Central Research Division (56) References JP-A-5-96627 (JP, A) (58) Survey Field (Int.Cl. ⁶ , DB name) B65D 23/00-25/56 B32B 15/08 104

Claims (3)

(57) [Claims] 1. A steel sheet surface corresponding to the outer surface of a can, a thermosetting adhesive layer / a printing ink layer for displaying a trademark design / a polyester film layer having a stretch orientation / static rubbing from the steel sheet side.
A lubricating coating layer having a friction coefficient of 0.2 and a thickness of 0.5 to 4 μm , or a thermosetting organic coating layer / thermosetting adhesive layer / printing ink layer displaying a trademark design from the steel plate side / Polyester film layer having stretch orientation / static friction coefficient
2. A three-piece can having a multi-layer organic coating on the outer surface of the can, characterized by having a multi-layer organic coating having a lubricating coating layer having a thickness of 0.5 to 4 μm . 2. The three-piece can according to claim 1, wherein the thermosetting organic coating layer contains a white pigment. 3. The total film thickness of the thermosetting adhesive layer / printing ink layer displaying a trademark design / polyester film layer having stretch orientation / lubricating film layer is 20 μm or less. 3. A three-piece can having a multilayer organic film on the outer surface of the can according to 1.