JP2998042B2 - Steel plate for three-piece cans with a striped multilayer organic coating - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION This invention can container, in particular relates to a coil-shaped three-piece steel sheet for cans performed by gluing or welding the joint of the can body, having a predetermined width direction of the coiled steel sheet
A plurality of strips continuously extending in the longitudinal direction at an interval
And has a stripe-shaped multilayer organic coating. More specifically, a thermosetting coating film and / or a thermoplastic resin film are provided on the surface corresponding to the inner surface of the can.
Trademark design has been printed film, a plurality of non-coated part of 1~10mm width in the width direction of the coil-like steel plate (non-film contact
The present invention relates to a steel plate for a three-piece can having a stripe-shaped multilayer organic film, which is continuously coated in the longitudinal direction of the coil-shaped steel plate across the attachment portion) .

[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 called a two-piece can, which is usually called a two-piece can, in which the can bottom is integrated with the can body, and is a typical can and is a DI can (Drawn and Ironed can) made by drawing and ironing.
And DrD cans (Draw)
and Reddraw cans). Another is a can body with a canopy wound around a canopy, usually called a three-piece can. Typical cans include solder cans, adhesive cans, and welding cans. And welding cans are the mainstream.

As materials for three-piece cans, tin plating, nickel plating, chromium plating and other materials 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.
The inner surface coating and outer surface printing are performed by cutting the above-mentioned 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 an outer surface printing (third time) at a cutting plate coating line. )). For applications requiring a high degree of corrosion resistance, the inner surface may be coated twice, and the outer surface may be printed twice for multicolor printing of five or more colors, resulting in four passes. In some cases, painting and printing for the inner and outer surfaces of the can may be performed by a plate or a five-pass plate. Then, each time the sheet is passed, the cutting plate needs to be heated in a baking furnace.

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 internal coating, white coating for external printing, and even external printing, but it is difficult to achieve printing accuracy when using a metal base. , Has not been put to practical use. The technology of laminating a film on a steel plate has been around for a long time,
The field of cans has also been studied in the past.
For example, Japanese Patent Application Laid-Open Nos.
As can be seen in JP-A-82717, the prior art mainly deals with two-piece cans such as drawn cans and drawn ironing cans and 18 l
There is no example of a coil steel plate for a three-piece can for use in cans and can lids, in which a film printed with a trademark design is laminated as in the present invention.

[0005]

As described above, currently used three-piece cans are manufactured through complicated painting and printing processes, and have poor productivity, long finishing periods, and a large number of manual operations. In short, it is difficult to upgrade the appearance of the printed finish, it is difficult to use ultra-thin steel sheets,
Due to such problems, the cost of cans has increased, which has caused a decline in competitiveness. Further, for a three-piece can, a trademark image with a beautiful printed appearance and a high-quality feel is required in the market, and further improvement in print quality on the outer surface of the can is considered necessary.

The present invention makes it possible to manufacture and supply coated steel sheets for three-piece cans in a coil state, and further enhances the corrosion resistance of the inner surface of the can and the decorativeness of the outer surface of the can to further enhance the three-piece image of the product. This makes it possible to provide painted steel plates for cans.

[0007]

It is a gist of the present invention SUMMARY OF] is on one surface of the coiled steel plate (can inner equivalent), slightly more width corresponding to the can diameter (circumferential length of the can) A plurality of narrow thermosetting coating layer and / or thermoplastic resin film layer, extending continuously in the longitudinal direction of the steel sheet and at an interval of 1 to 10 mm in the width direction of the steel sheet , The steel
On the other side of the plate (corresponding to the outer surface of the can), a thermoplastic resin film layer having a printing ink layer displaying a trademark design is provided.
Continuously in the longitudinal direction of the steel sheet and 1 to 1 in the width direction of the steel sheet
It extends a plurality of lines at intervals of 10 mm, and
Thermoplastic resin film layer having ink layer and thermosetting
In a three-piece cans steel sheet having a stripe-shaped multilayer organic coating, characterized in that the coating layer and / or a thermoplastic resin film layer is on the front and back corresponding positions.

[0008] The basic idea of the present invention, by direct continuous printing to the coiled steel sheet is subjected to continuous printing on to difficult film is continuously laminated printed film coiled steel sheet, coil This makes it possible to indirectly perform continuous printing on shaped steel plates. In the manufacturing process of the three-piece can, both surfaces of the surface-treated steel sheet are coated with an organic film for the inner surface of the can and for the outer surface of the can, and cut into a size equivalent to the size of the can.
Repair painting of the body and can body joints by welding or bonding,
Necked-in processing, ground cover tightening, filling of contents, and canopy winding are performed. After filling, high-temperature sterilization processing (retort processing) is further performed.

In the present invention, the non-painted portion of 1 to 10 mm (f)
The reason for providing the film non-adhesive portion is that the center of the portion is cut to a size corresponding to the can size to provide a joint wrap margin (overlapping portion) for the cylinder. The joint wrap allowance for the cylinder can be slightly different between the welding can and the adhesive can, but is, for example, about 0.5 mm in the case of a welding can. Therefore, in a strict sense, a non-painted portion (film non-adhesion portion) of about 1 mm may be provided, but in the case of a cylinder made by welding, heat is generated at the time of welding, while in the case of a cylinder made by adhesion, heat is applied. Since it is affected by the heat, it is necessary to make sure that the heat effect does not reach the laminated film as much as possible by any means. In this sense, non-painted parts (film non-adhesive
Part) is 1 to 10 mm, preferably 2 to 10 mm.
4mm is optimal.

[0010] The width of the painted portion (film laminated portion) is the length equivalent to the can diameter after cutting, including the unpainted portion (film non-adhered portion) , and it is necessary to make various lengths according to the can size. There is. Non-painted parts (film non-adhesion)
Part)) , when manufacturing a coiled steel sheet having a film lamination method, generally, the coiled steel sheet is slit into a strip having a required dimension width, and a film narrower than the prepared steel sheet width is formed thereon. A method of laminating while leaving both ends of the coiled steel sheet is adopted, but this method provides a technically reliable manufacturing method, but it is necessary to cut out the coiled steel sheet and the film to the required dimensions in advance, and It is unsatisfactory in terms of productivity because they are manufactured one by one.

According to the present invention, it is possible to realize a coating and printing process with excellent productivity by laminating a film on a stripe on the entire surface in the width direction without previously slitting the coiled steel sheet in a strip shape. is there. Hereinafter, the role of each layer constituting the film of the present invention will be described. The resin film on the outer surface of the can serves as a base for performing continuous printing as described above. Mainly through the substrate film, the coil creates a composite film having a multilayer structure of the adhesive layer / printing ink layer / base film layer / lubrication film layer or an adhesive layer / base film layer / printing ink layer / lubricating film layer laminating Jo steel sheet surface.

[0012] Among the constituent layers of the composite film, the printing ink layer displays a brand name and the like, and has a trademark design printed thereon. The lubricating film layer is provided for the purpose of preventing the film from being damaged in a high-speed can-making line, and is necessary for securing appearance such as sharpness. The adhesive layer is required for the pre-printed film to be laminated with sufficient adhesion.

A thermosetting organic coating layer may be used as a base to ensure the sharpness of the printed appearance of the composite film applied to the outer surface of the can or to assist the adhesion. The film for the inner surface of the can is intended to maintain the contents (corrosion resistance), and as described above, the inner surface may need to be coated twice for applications requiring high corrosion resistance. The lamination method can be used for all applications by changing the thickness and the type of resin.

Next, each of the multilayer organic coating layers used in the present invention will be described. Although the manufacturing process of the three-piece can has been outlined above, in particular, repair painting of the can body joint is an essential item in the case of a welded can, and various repair paintings are performed depending on the contents to be filled. This repair coating is in the direction of baking for a short time in terms of productivity, and may reach a temperature of 280 ° C. in some cases. The retort treatment is usually performed at a temperature of 110 to 130 ° C for 20 to 60 minutes. Therefore, it is needless to say that the film laminated on the inner and outer surfaces of the can must withstand these steps, and is limited in terms of heat resistance and water resistance.

The film applied to the present invention is a thermoplastic resin film such as a polyester film, a polypropylene film and a nylon film. The main purpose of the laminated film for the inner surface is to secure corrosion resistance to the contents, but if the heat resistance at the time of baking of the repair coating is not sufficient, it will melt locally, and if it is severe, defects will occur, impairing the coating property and remarkably corrosion resistance Poor results may occur. Therefore, it is needless to say that it is necessary to use a film suitable for the above-mentioned baking conditions for repair painting of the joint.

Since the melting point of the polypropylene film is about 165 ° C., the baking temperature of the repair coating is 16
Useful for applications below 0 ° C. In the case of a nylon film, since the melting point is about 225 ° C., it can be applied when the baking temperature of the repair coating is 220 ° C. or less. In the case of a polyester film, a high melting point of about 265 ° C. can be obtained by selecting an alcohol component and an acid component, and heat resistance can be ensured.

Next, regarding water resistance, it is desirable to use a resin film having a water absorption of 1% or less, for example. 1
%, When a film having a water absorption rate of more than 1% is applied, corrosion of the base steel sheet easily occurs during the retort treatment described above,
It is not preferable because the content may be deteriorated.
Accordingly, the polyester film, the polypropylene film, and the polyethylene film all have a water absorption of 1% or less, which is not a problem. However, when a nylon film is used, it is necessary to avoid using a film such as nylon 6.

Next, in the present invention, the film thickness on the inner surface of the can is 5 to 50 μm. The reasons for limiting the film thickness to 5 to 50 μm are as follows. That is, a thickness of less than 5 μm is not sufficient for assuming film damage in the can making process and ensuring sufficient preservation of the contents. on the other hand,
Even if it exceeds the upper limit of 50 μm, the effect is saturated in terms of corrosion resistance,
Economically disadvantageous. The thickness of the inner film to be laminated is preferably 12 to 40 μm, more preferably 16 to 40 μm.
30 μm is preferred.

The thickness of the film on the outer surface of the can is 5 to 25 μm.
Applies. If the lower limit is less than 5 μm, if the film is damaged in the can making process, it causes rust spots,
It is not preferable because the appearance is deteriorated. On the other hand, the upper limit 2
Even if it exceeds 5 μm, the effect is saturated in terms of rust generation, which is economically disadvantageous. Preferably, the thickness is 8 to 20 μm. As the film bonding method in the present invention, a heat bonding method or an adhesive application method is employed. Polyester film and nylon film are heat-bondable resin films themselves, so they can be directly heat-bonded to the surface of a heated steel plate. To the extent that there is no problem, a method of modifying with, for example, maleic acid or maleic anhydride to enable thermal bonding is employed.

As the adhesive application method, a method in which a urethane or polyester adhesive containing a curing agent is applied and dried is used. The thickness of the adhesive layer is 1 to 5 μm. 1
If it is less than μm, sufficient adhesive strength cannot be ensured. Also 5μm
The effect saturates even if it exceeds. Preferably 1.5-4 μm
It is. Also, when applying an organic film to the inner surface of the can, epoxy, epoxy phenol, epoxy ester,
Epoxy urea, acrylic, polyester paint, etc.
What is currently used as a paint for the inner surface of a can is applied. The coating amount may be 5 to 10 μm as a dry film thickness, and a current roll coating method or the like can be adopted as a coating method.

When a thermosetting organic coating film is applied to the outer surface of the can as a base material of the laminated film, an epoxy-based, acrylic-based, polyester-based paint or the like is used, and a titanium oxide-based white pigment is contained in an amount of 0 to 30%. The lower limit of 0% means no addition. However, when a white pigment is added, the effect of whitening is small at 1% or less, and the effect of whitening is almost saturated at more than 30% and the coating film is coated. The properties tend to deteriorate, and preferably 30% or less. A more desirable range is 10 to 2
The range is 5%.

The thickness of the thermosetting organic coating layer is 1 to 15 μm.
However, when the white pigment is not contained, the thickness of the coating layer is 1
The thickness of the coating film is preferably from 5 to 15 .mu.m when a hue due to a white pigment is expected. Next, the lubricating film layer and the printing ink layer on the outer surface of the can will be described. The lubricating film of the outermost layer of the film is applied from the viewpoint of preventing the film from being damaged and passing through the plate in the can making process, and a film having a static friction coefficient of 0.2 or less is advantageous. A film in which Si-based fine particles or an organic lubricant is contained in a paint is applied. 0.1 ~
5 μm. If it is less than 0.1 μm, the coefficient of friction does not decrease and no effect is observed. If it exceeds 5 μm, the effect will be saturated without further reduction of the friction coefficient. The thickness of the lubricating film on the film is preferably 1 to 4 μm.

The printing ink layer applied to the present invention is for printing a trademark design, and is printed with an ink having excellent heat resistance and retort resistance using a urethane resin as a main binder. It is judged that gravure printing is preferable in order to ensure the sharpness of the trademark design, which is an important object of the present invention. The thickness of the ink layer varies depending on the trademark design, and is basically not limited.

On the surface of the steel plate corresponding to the outer surface of the can of the present invention,
A dry lamination method in which a film previously printed with a lubricating film and a trademark design is laminated on a steel plate coated with an adhesive, or after a lubricating film and a trademark design are printed on the film in advance, the adhesive is applied to the ink layer surface. multilayer organic coating from <br/> the method in which laminated to the heated was coated and dried film steel is subjected. The steel sheet having the multilayer organic film thus obtained can be made by a three-piece can body making means such as a normal welding can or an adhesive can.

The means for laminating the film on the steel sheet surface corresponding to the inner and outer surfaces of the can in the present invention is as described for the inner and outer surfaces, respectively. Therefore, the dimensional accuracy and shape of the laminated film are important. As the heating means for the steel sheet, an electric heating method, a high-frequency induction heating method, a hot air heating method, an infrared heating method or the like can be used alone or in combination.

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, the adhesion amount 0.5 to 3.0 g / m ² after tin plating, tin-plated steel sheet subjected to chemical conversion treatment, after the nickel coating weight 0.3 to 2.0 g / m ^2, the chemical conversion treatment Nickel plated steel sheet, Sn and Ni adhesion amount of 0.5 to 2.0 g /
After plating m ² , 0.1 to 0.5 g / m ² in the order of Ni and Sn,
Sn / Ni plated steel sheet subjected to chemical conversion treatment, metal Cr deposition amount 50~120mg / m ^2, Cr oxide adhesion amount 5 to 20 mg / m ²
And a chromium-chromate treated steel plate which is usually called TFS (Tin Free Steel).

[0027]

EXAMPLES The effects of the present invention will be specifically shown in the following examples. Example 1 Sn / Ni with a tin adhesion of 1.0 g / m ² and a nickel adhesion of 0.3 g / m ^{2 on} the surface of a steel plate having a thickness of 0.20 mm and a width of 832 mm.
After plating and chromate treatment, an 8 μm thermosetting epoxy ester-based paint containing a white pigment was applied on a surface corresponding to the outer surface of the can with a roll coater to a width of 162.0 mm and uncoated portions 1.9 mm on both ends. (Total 165.8 mm), and five coatings were continuously performed in the width direction of the plate.

Next, the steel sheet is heated in a hot air oven to cure the paint. When the sheet temperature reaches 180 ° C., the low melting point adhesive layer is formed on the inner surface of the can so as to correspond to the position of the coating film. A biaxially stretched polyester film having a thickness of 16 μm and a width of 162 mm having 5
Heated to ° C. When the plate temperature reaches 200 ° C., a thickness of 12 μm having a printing ink layer and a lubricating film layer is obtained.
m biaxially stretched polyester film, thickness 2.5μm
After being continuously adhered to the outer surface of the can with just the same width and directly above the white coating surface with the urethane-based adhesive, the mixture was quenched.

A steel sheet having a striped multilayer organic film wound in a coil shape has a width of 165.8 mm (can diameter of 5 mm).
2.6mm equivalent, 1.9mm unpainted parts at both ends), 136.2mm long (equivalent to can height), cut out blanks per can and welded so that the printing surface is the outer surface of the can The can body was manufactured on line. The outer surface of the obtained can body has good gloss,
No color unevenness occurred. Also, the sharpness of the trademark design was better than three-piece cans directly printed on current steel plates.

The thus obtained can body is subjected to necked-in processing at the existing can-making line, and after further tightening the ground cover,
% Saline solution, the canopy was tightly wound, and retorted at 125 ° C. for 30 minutes. As a result, the coating layer on the outer surface of the can has no peeling, good adhesion, and no change in appearance,
The sharpness was ensured. On the other hand, no corrosion of the body of the can was observed on the inner surface of the can. For the inside of the can,
Thereafter, after storage for one month at 38 ° C., a reexamination was carried out, but no corrosion of the can body was found again. Example 2 A 25 μm biaxially stretched polyester film having a low melting point adhesive layer on one side of a Ni-plated steel sheet (chromate treatment) having a thickness of 0.18 mm, a width of 832 mm and an adhesion of 0.53 g / m ^{2 was} prepared by using 162. A non-painted portion (film non-adhesion portion) of 1.9 mm (165.8 mm in total) was provided at both ends with a width of 0 mm, and five films were thermally bonded in the width direction of the plate at a plate temperature of 180 ° C and further at 200 ° C. Until heated. When the sheet temperature reached 200 ° C., a polyester-based lubricating film containing Si-based fine particles was applied to a 15 μm biaxially stretched polyester film by 2 μm.
m After coating and drying, a film with a gravure printed trademark design on the opposite side is continuously coated with a 1.5 μm-thick urethane-based adhesive in a positional relationship corresponding to the front and back sides of the previously laminated 25 μm biaxially stretched polyester film. Adhesively,
It was quenched, dried, and wound into a coil.

In the same process as in Example 1, a welding can was manufactured, filled with coffee, and then subjected to a retort treatment at 120 ° C. for 15 minutes. The appearance of the obtained can was excellent in gloss and no occurrence of color unevenness was observed. Also, the sharpness of the trademark design was better than the current three-piece can. On the other hand, no corrosion of the body of the can was observed on the inner surface of the can.
The inner surface of the can was then re-examined after storage at 38 ° C. for 3 months, but again no corrosion of the can body was confirmed.

Example 3 Using the same steel plate as in Example 1, an epoxy paint having a thickness of 5 μm was coated on one side, and a thermosetting polyester paint having a thickness of 10 μm containing a white pigment was coated on the other side. 162.0mm painted part, 1.9mm unpainted part on both ends
(Total 165.8 mm), and five strips of coil coating were continuously performed in the board width direction. Next, the coated steel sheet is heated and dried in a hot air oven, and a multilayer structure including an adhesive layer / printing ink layer / film layer / lubricating film layer is formed on a thermosetting polyester paint used as an outer surface of the can. Film
The layers were stacked so as to overlap a width of 162.0 mm. 162.0mm
Films having a width were laminated simultaneously in five rows in the width direction.

In the same process as in Example 1, a welding can was manufactured, and after filling with tomato juice, a retort treatment was performed at 125 ° C. for 30 minutes. The appearance of the obtained can was excellent in gloss and no occurrence of color unevenness was observed. Also, the sharpness of the trademark design was better than the current three-piece can. on the other hand,
No corrosion of the body of the can was observed on the inner surface of the can. The inner surface of the can was then re-examined after storage at 38 ° C. for 3 months, but again no corrosion of the can body was confirmed.

[0034]

The invention guarantees a number of advantages. By using a wide coil, it is possible to perform continuous coating printing on a high-speed line, and it is possible to secure about twice the productivity as compared with the conventional plate coating line. Secondly, the in-process period can be shortened because a large number of line passing operations are not required. 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. It is possible to solve at once the problems in the conventional painting printing process of steel plates for three-piece cans, such as upgrading the appearance of printing by gravure printing and saving labor by omitting the process.

────────────────────────────────────────────────── ─── Continued on the front page (72) Tomohiko Hayashi 20-1 Shintomi, Futtsu City, Chiba Prefecture Nippon Steel Corporation Central Research Division (56) References JP-A-63-270581 (JP, A) Kaihei 3-8533 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B32B 15/08 B05D 7/14 B65D 8/16 B65D 25/14

Claims (5)

(57) [Claims] 1. One surface of a coiled steel plate (corresponding to the inner surface of a can)
The thermosetting slightly narrower width than the width corresponding to the can diameter coating layer and / or a thermoplastic resin film layer, steel
1 to 10 continuously in the longitudinal direction of the plate and in the width direction of the steel plate.
The steel sheet extends a plurality of lines at intervals of mm , and a thermoplastic resin film layer having a printing ink layer indicating a trademark design is provided on the other surface (corresponding to the outer surface of the can) of the steel sheet in a longitudinal direction of the steel sheet.
1-10mm interval in the width direction of the steel sheet continuously in the width direction
With the printing ink layer
Thermoplastic resin film layer and the thermosetting coating film layer and
And / or a thermoplastic resin film layer at a position corresponding to the front and back, a steel sheet for a three-piece can having a striped multilayer organic film. 2. The stripe according to claim 1, wherein the film laminated on the surface of the steel plate corresponding to the inner surface of the can is a thermoplastic resin film such as a polypropylene film, a nylon film or a polyester film having a thickness of 5 to 50 μm. Steel sheet for three-piece cans with a multi-layered organic coating. 3. A film laminated on a steel plate surface corresponding to an outer surface of a can comprises an adhesive layer / printing ink layer / polyester resin.
Multilayer of film layer / lubricating film layer with static friction coefficient of 0.2 or less
The three-piece steel sheet for a three-piece can having a striped multilayer organic film according to claim 1 or 2 , having a structure . 4. A film laminated on the surface of a steel sheet corresponding to the outer surface of a can comprises an adhesive layer / a polyester resin film layer / a mark.
Multi-layer printing ink layer / lubricating film layer with a static friction coefficient of 0.2 or less
The three-piece steel sheet for a three-piece can having a striped multilayer organic film according to claim 1 or 2 , having a structure . 5. A thermoplastic resin having a thermosetting coating film containing 0 to 30% by weight of a pigment on the surface of a steel sheet corresponding to the outer surface of a can, and a printing ink layer for displaying a trademark design on the thermosetting coating film. The three-piece steel sheet for cans having a striped multilayer organic film according to claim 1, further comprising a film layer.