JP2002012986A - Metal can body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal can body for drink, having a superior corrosion resistance, a flavor nature, an economical efficiency, and safety. SOLUTION: This metal can body is obtained by forming a two piece can from a metal sheet laminated with an organic resin at least on the one side, and dry coating preferably one or more kinds of a carbon film of 0.1-10 μm thick, an amorphous carbon film, a diamond carbon film, a silica film, or a silicon oxide film, on the inside and/or outside of the can, and a manufacturing method therefor is also provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a beverage can having excellent corrosion resistance, flavor, economy, and stability.

[0002]

2. Description of the Related Art At present, as a metal can for beverages, a two-piece can (a can body consisting of a part where a bottom lid is integrated with a body and an upper lid) is used.
And three-piece cans (can bodies consisting of a body, a bottom cover, and a top cover) have been put to practical use. The two-piece can and the three-piece can differ greatly in the method of making them. 0.15-0.3m for 2-piece cans
Draw and ironing (DI) or draw and redraw (DRD)
Processing) or draw stretch processing (DTR processing)
It is made by doing. The cans formed by these processes are called DI cans, DRD cans, and DTR cans, respectively.
Many of the two-piece cans are DI cans. In any of the can bodies, the thickness of the body of the can body is smaller than the original thickness by these processes. In particular, in the case of the DI can, the thickness of the can wall is 0 at a thin place. .1 mm or less.

[0003] After DI processing, DI cans are manufactured by performing continuous processes from degreasing of lubricating oil, chemical conversion treatment, washing, outer coating, printing, inner coating by spraying, and neck processing in a continuous process. ing. Thereafter, the empty can is shipped to a beverage maker and filled with the beverage. On the other hand, a 3-piece can is painted and printed on a steel plate with a thickness of 0.15 to 0.25 mm, sheared to a predetermined size, processed into a cylindrical shape, and the overlapping portions of the steel plate are glued or welded. By joining, the body of the can is manufactured. Subsequently, neck processing is performed, a lid is attached, and an empty can is manufactured. Then, like the DI can, it is shipped to a beverage maker. The three-piece can has no reduction in sheet thickness due to can-making unlike the two-piece can.

[0004] Since the strength of the wall portion of the two-piece can is weak, the internal pressure is generated inside the can with a beverage containing gas, so that the can strength necessary for practical use is ensured. That is, the two-piece can is mainly filled with carbonated beverages such as beer, cola, and soda water. In recent years, a technique has been developed in which liquid nitrogen is dropped after filling a beverage to secure the internal pressure with nitrogen gas.
Sports drinks and health drinks are also being filled.
The three-piece can has a stronger can wall portion than the two-piece can. Therefore, non-internal pressure beverages without internal pressure, such as coffee, tea and fruit tree juice, are filled.

In recent years, corrosion resistance,
Aggressive measures have been required to improve flavor, economy, and safety, and to further reduce the burden on the global environment. For such a trend, do not use paint,
Laminating cans for laminating a PET film instead of painting (Japanese Patent Application Laid-Open Nos. Hei 7-2241 and Hei 7-1956)
No. 19, Japanese Patent Application Laid-Open No. 8-244750).
It has been put to practical use and is penetrating the market. The two-piece laminated cans are different from the conventional two-piece can making method in which a painted coating is applied. That is, first, a PET film is laminated on both sides or one side of a steel plate or an aluminum plate (in the case of one side, the side which becomes the inner surface of the can after molding). From this laminated plate, DI processing, DRD processing, and DTR processing are performed, and respective can bodies are manufactured. Subsequently, a design print or a printed film is laminated on the outer surface side of the can body, a neck process is performed, and an empty can is manufactured.

[0006] Also, a can body processed into a bottle shape as a new two-piece can has been put to practical use. This can body is PE
DI processing is performed on the metal plate on which the T film is laminated. Thereafter, the bottom of the can is drawn into an elongated shape, threaded, an opening is provided, a cap is attached, and a bottle-shaped empty can is manufactured. Three-piece laminated cans do not differ significantly from conventional manufacturing methods. That is, first, a plain PET film is laminated on the side of the steel sheet can that becomes the inner surface, and a printed film is laminated on the side of the steel sheet can that becomes the outer surface, and sheared to a predetermined size. It is processed into a cylindrical shape, and the overlapping portions of the steel plates are welded to produce the body of the can. Subsequently, neck processing is performed, a lid is attached, and an empty can is manufactured.

[0007]

Recently, with the spread of the Internet, as seen in the dioxin and environmental hormone problems, the fluidity of information has increased at a stretch, and the corrosion resistance, flavor, economy, safety, Interest in the global environmental load has become extremely large, and beverage cans have been required to have even higher corrosion resistance, flavor, economy, and safety.

[0008] The above-mentioned laminated can certainly has improved corrosion resistance, flavor, economy, and safety as compared with cans using a conventional coating. However, a two-piece laminated can has a large thickness reduction after lamination.
Since I processing, DRD processing, and DTR processing are performed, the laminated PET film may be damaged by these processing. Cans with damaged film can be removed by inspection equipment, resulting in reduced yield. Further, since the bottle-shaped can is further subjected to the bottle-like processing after the DI processing, the can is easily damaged more than the DI processing. Also, the three-piece laminated cans are not processed like the two-piece cans, so there is no damage to the film. Has not been reached.

[0009]

Means for Solving the Problems The present inventors have intensively studied the above-mentioned problems in order to improve the corrosion resistance, flavor, economy and safety of two-piece and three-piece laminated cans. went. As a result, after the completion of the molding process to drastically avoid damage to the can body surface film due to the can manufacturing process, the surface of the can body is coated,
Instead of using the spray used for the manufacture of two-piece cans, the coating utilizes a dry process that can coat diamond-like carbon (DLC) even on cans of complex shapes. The solution has been reached.

That is, the present invention provides: (1) A metal can body characterized in that a dry coating is applied to the inner surface of the can and / or the outer surface of the can. (2) A two-piece can molded from a metal plate having at least one surface laminated with an organic resin, wherein the inner surface of the can or /
A metal can body having a dry coating on the outer surface of the can. (3) A three-piece can molded from a metal plate having at least one surface laminated with an organic resin, wherein the inner surface of the can or /
A metal can body having a dry coating on the outer surface of the can. (4) When the film provided by dry coating is 0.1
The metal can according to any one of (1) to (3), wherein one or two or more of a carbon film, an amorphous carbon film, a diamond-like carbon film, a silica film, and a silicon oxide film having a thickness of 10 μm to 10 μm are provided.

(5) The film applied by dry coating is formed by chemical vapor deposition (CVD), physical vapor deposition (PVD),
The metal can according to any one of (1) to (4), which is any one of plasma coating. (6) The metal can according to any one of (1) to (5), wherein the can has one or two openings. (7) The metal can according to (1) to (6), wherein the material is aluminum or / and steel. (8) An object of the present invention is to provide the metal can according to any one of (2) to (7), wherein the organic resin is a film mainly made of polyethylene terephthalate (PET) and having a thickness of 80 μm or less. .

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a metal can body which is excellent in corrosion resistance, flavor, economy, and safety, which are functions of the present invention, and a method for producing the same will be described in detail. The metal used for the metal can used in the present invention is not particularly limited, and a conventionally used steel plate or aluminum plate is used. In some cases, the surface treatment applied to these metal plates is not particularly limited. However, it is economically disadvantageous to perform the surface treatment. Therefore, it is preferable not to perform the surface treatment.

[0013] If necessary, use a PET
A film is laminated on at least the inner surface of the can. The type of the PET film is not particularly limited, and a film mainly composed of PET (polyethylene terephthalate) may be used. Even if the PET film has a multilayer structure or is coated with an adhesive, the essential point of the present invention is not affected. If the thickness of the PET film is too large, not only is it economically disadvantageous, but it also hinders DI processing and DTR processing due to the inflow of materials, and makes it difficult to perform processing smoothly. Therefore, when attaching a PET film, it is desirable that the thickness be 80 μm or less. Needless to say, it is economically desirable not to laminate the PET film.

The metal plate is processed by a conventional can-making method to produce a can body. There is no particular limitation on the method of manufacturing the can. That is, in the case of a two-piece can, a can body is manufactured from this metal plate by DI processing or DTR processing. After that, a film printed on the outer surface or printed on the outer surface is laminated, and in the case of a neck processing and a three-piece can, this metal plate is sheared to a predetermined size, processed into a cylindrical shape, and the overlapping portions of the steel plate are removed. The body of the can is manufactured by bonding with an adhesive or welding. Subsequently, neck processing is performed, a lid is attached, and a can body is manufactured.

After these cans have been manufactured, coating is performed, which is the essence of the present invention. From the viewpoint of ensuring corrosion resistance, flavor, and safety, the film applied by coating is a carbon film, an amorphous carbon film,
A diamond-like carbon film, a silica film, and a silicon oxide film. Since all of these films are chemically stable and have gas flavor properties, these films are applied to the inner surface of the can to prevent corrosion caused by the beverage as a content, and to enhance the flavor property of the content. And safety can be ensured. Further, by providing these coatings on the outer surface of the can, excellent rust resistance can be ensured.

In order to ensure the excellent properties of these carbon films, amorphous carbon films, diamond-like carbon films, silica films, and silicon oxide films, it is necessary that the surface of the can be uniformly coated, Alternatively, if a large amount of the non-coated portion remains, the effect of the original coating film is not exhibited. That is, if the film thickness is too thin, the coating is not sufficiently applied. Therefore, in practical use, the film thickness substantially covers the surface of the can body and exhibits the effect of the coating.
The above is necessary. When the film thickness is increased, the effect of improving corrosion resistance and flavor properties is increased. However, when the film thickness is too large, the adhesion of the film itself may be deteriorated and the film may be peeled off. Therefore, the film thickness is desirably 10 μm or less. . Also, 10 μm
In the above, the processing time becomes long, and it is economically disadvantageous.
For the above reasons, the thickness of the film to be coated is
It is highly desirable that the thickness be 0.1 μm to 10 μm.

The coating of this film is usually applied to the inner surface of the can or the outer surface of the can, but the inner surface and the outer surface of the can body may be separately coated, or the same film may be applied simultaneously to the inner and outer surfaces. Alternatively, a multi-layer coating may be applied.
These treatments are desirably performed by chemical vapor deposition (CVD), physical vapor deposition (PVD), or dry coating by plasma coating, from the viewpoint of sufficiently securing economic productivity and quality stability. In the present invention, the dry coating apparatus is not particularly limited. In addition, there is no particular restriction on handling when processing can bodies. For example, when coating the inner surface, it can be performed by a plasma coating method or a CVD method in which a gas adjusted to a predetermined component is blown into the inner surface of a can body one by one to generate plasma and coat the inside. A predetermined component may be coated by a PVD method by depressurizing the inner surface. Also, when coating the outer surface of the can, put hundreds to thousands of cans in a vacuum container and batch-
Can be coated.

[0018]

EXAMPLES Examples and comparative examples of the present invention will be described below. Test samples were manufactured by the methods described in the following (A) to (F). The evaluation of the prepared sample is (1)-
It carried out by the method described in (III). Table 1 shows the results. (A) From a 160 mm square steel plate having a thickness of 0.24 mm and a PET film having a thickness of 10 μm laminated on one side,
DI processing with PET film side inside the can
External printing was performed and neck processing was performed to produce a can body.
Attachment with several nozzles was attached as if to cover the opening of the can, and the pressure was reduced. Then, acetylene gas was sprayed and heated to generate plasma, and the film thickness was 0.05 μm (No. 1). ), 0.4 μm (No. 2),
1.2 μm (No. 3), 7 μm (No. 4), 14 μm
m (No. 5) of diamond-like carbon was coated on the inner surface of the can.

(B) From a 160 mm square steel plate having a plate thickness of 0.24 mm, DI processing was performed, external printing was performed, and neck processing was performed to manufacture a can body. Attachment with several nozzles was attached to the opening of the can as if it were covered with a lid, the pressure was reduced, then acetylene gas was sprayed and heated to generate plasma, and the film thickness was 0.05 μm (No.
6), 0.4 μm (No. 7), 1.2 μm (No.
8), 7 μm (No. 9) and 14 μm (No. 10) diamond-like carbon were coated on the inner surface of the can.

(C) From a 180 mm square aluminum plate having a thickness of 0.27 mm, DI processing was performed, a film having an outer surface printed thereon was laminated, and neck processing was performed to produce a can body. Attachment with several nozzles was attached as if to cover the opening of the can, pressure was reduced, then acetylene gas was sprayed and heated to generate plasma, and the film thickness was 0.05 μm (No. 11). ), 0.4 μm (No. 1)
2), 1.2 μm (No. 13), 7 μm (No. 1)
4) 14 μm (No. 15) diamond-like carbon was coated on the inner surface of the can.

(D) A 160 mm square plate thickness 0.24 mm in which a PET film having a thickness of 10 μm is laminated on one side.
DT with the PET film surface inside the can from the steel plate of
R processing was performed to produce a can. The can is batch type C
It was inserted into a VD apparatus, and hexamethyldisiloxy acid gas was inserted to generate plasma.
6), 0.4 μm (No. 17), 1.2 μm (No. 17).
18), 7 μm (No. 19), 14 μm (No. 2)
The silica coating of 0) was coated on the inner and outer surfaces of the can.

(E) Using a steel plate having a thickness of 0.18 mm laminated with a film having a printed surface on one side, a 200 ml-sized welding can with the film side outward is manufactured.
Neck processing was performed, and a lid was attached to one side to produce a can body. Attachment with several nozzles was attached as if to cover the opening of the can, pressure was reduced, then acetylene gas was sprayed and heated to generate plasma, and the film thickness was 0.05 μm (No. 21). ), 0.4 μm (No. 2)
2), 1.2 μm (No. 23), 7 μm (No. 2)
4) 14 μm (No. 25) diamond-like carbon was coated on the inner surface of the can.

(F) A 160 mm square plate thickness of 0.22 mm in which a PET film having a thickness of 10 μm is laminated on one side.
From the steel sheet of the above, with the PET film surface facing the inner and outer surfaces of the can.
I processing was performed, and the bottom of the can was further drawn to form a bottle-shaped can body, the tip was cut, and a screw cap was attached. Thereafter, external printing was performed, and neck processing was performed on the processed portion to produce a can. Attachment with several nozzles was attached to the opening of the can as if it were covered, and the pressure was reduced. Then, acetylene gas was sprayed and heated to generate plasma, and the film thickness was 0.05 μm (No. 2).
6), 0.4 μm (No. 27), 1.2 μm (No. 27).
28), 7 μm (No. 29), 14 μm (No. 3)
0) Diamond-like carbon was coated on the inner surface of the can.

(I) Corrosion resistance test on inner surface of can: In order to investigate the corrosion resistance of the inner surface of the can, a commercially available carbonated beverage is filled in the manufactured can, a lid is attached, and the can is stored at 55 ° C. for 3 months. went. After the test, the corrosion status was evaluated in four stages (◎:
No corrosion is observed. ○: Very slight corrosion is observed to the extent that there is no practical problem. Δ: Partial corrosion is observed.
X: severe corrosion was observed in most cases) and comprehensively evaluated.

(II) Corrosion resistance test on the outer surface of the can: In order to investigate the rust resistance of the outer surface of the can, the manufactured can was stored in a humidity chamber at a humidity of 90% and a temperature of 55 ° C. for one week, and a rust test was performed. . After completion of the test, the rusting was evaluated in four stages (（: no rusting was observed, ：: very slight rusting was observed without practical problems, Δ: partial rusting was observed, ×: Rust was observed in most cases) and comprehensively evaluated.

(III) Flavor property: The produced can was filled with distilled water, a lid was attached, and retort treatment was performed at 125 ° C. for 30 minutes. Open the lid, transfer distilled water to a glass container, and measure the odor and taste in four stages according to a sensory test (◎: no odor or taste is recognized, ○: very slight odor or taste of practically no problem, Δ: odor or taste was recognized, x: unpleasant odor or taste was recognized), and the flavor was evaluated.

(IV) Adhesion: The prepared can was filled with water, dropped from a height of 50 cm, and the state of peeling of the film on the deformed portion of the can was observed. , ：: Extremely slight peeling to the extent that there is no practical problem was observed, Δ: Partial peeling was observed, and X: Vigorous peeling was observed). As shown in Table 1, it was revealed that the present invention can provide a beverage can having excellent corrosion resistance, flavor, economy, and safety.

[0028]

[Table 1]

[0029]

As described above, according to the present invention, it has become possible to provide a beverage can having extremely excellent corrosion resistance, flavor, economy and safety.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C23C 16/26 C23C 16/26 16/40 16/40 F term (Reference) 3E033 AA06 BA08 BA09 BA18 EA10 3E061 AA16 AB05 AB08 AB13 AC01 AC07 AC09 AD01 BA02 4K029 AA26 BA34 BA46 BB10 BC01 BD00 CA00 FA07 4K030 BA27 BA44 BB05 CA02 CA11 DA02 FA01 LA01 LA24 4K044 AA02 AA06 AB03 BA21 BB03 BC02 CA14 CA31

Claims (8)

[Claims] 1. A metal can body having a dry coating applied to the inner surface of the can and / or the outer surface of the can. 2. A two-piece can molded from a metal plate having at least one surface laminated with an organic resin, wherein the inner surface of the can and / or the outer surface of the can are dry-coated. 3. A three-piece can molded from a metal plate having at least one surface laminated with an organic resin, wherein the inner surface of the can and / or the outer surface of the can are dry-coated. 4. The method according to claim 1, wherein the thickness of the film provided by the dry coating is at least one of a carbon film, an amorphous carbon film, a diamond-like carbon film, a silica film, and a silicon oxide film having a thickness of 0.1 to 10 μm. Claim 1 to claim
3. The metal can according to 3. 5. The metal can body according to claim 1, wherein the coating applied by dry coating is any one of chemical vapor deposition (CVD), physical vapor deposition (PVD), and plasma coating. . 6. The metal can body according to claim 1, wherein one or two openings are provided in the can body. 7. A metal can according to claim 1, wherein the material is aluminum or / and steel. 8. The metal can according to claim 2, wherein the organic resin is a film mainly composed of polyethylene terephthalate (PET) and having a thickness of 80 μm or less.