JP6969146B2 - Mirror label and its manufacturing method - Google Patents

Description

The present invention relates to a label applied to a container such as a metal can, and more particularly to a mirror surface label having a mirror surface gloss and beautifully printed by gravure printing and an efficient manufacturing method thereof.

Metal cans made from metals such as aluminum and steel have high impact resistance, do not allow gas such as oxygen to permeate, and have much better storage stability than plastic containers. It has advantages such as lighter weight than glass bottles, and is widely used as a container for carbonated beverages, alcoholic beverages, other beverages and various foods.

In such a metal can, the can body is directly printed and the trademark, manufacturer, other various product information, designs, etc. are displayed, but the curved surface printing on the can body is aesthetically pleasing. Since it is difficult to form an excellent and clear printed image, a method is adopted in which a resin film on which a printed image is formed is separately produced and the resin film is attached to the body of a metal can.
In recent years, it has been desired for metal cans to have a high-class feeling and to have a printed image with excellent decorativeness that can motivate the purchaser, and especially for metal cans, mirror gloss is emphasized. There is.

However, in seamless cans formed by squeezing aluminum alloy plates, surface-treated steel plates, etc. and performing ironing or stretch draw processing, the skin becomes rough due to harsh processing, and sufficient mirror gloss can be obtained. It is difficult, especially for seamless cans molded from resin-coated metal plates, because the metal surface does not come into direct contact with the molding tool, the metal surface under the resin coating has a large rough surface, and aluminum cans that are relatively easy to obtain metallic luster. However, it is not possible to obtain a mirror surface gloss.
From this point of view, a label made of a resin film on which a printed image to be used is wound around a metal can is provided with a brilliant metal foil or a metal vapor deposition layer together with a printing layer to form a label having a mirror glossy feeling. However, in a label can made by attaching these labels to a metal can, a large number of blister is generated, and a satisfactory mirror surface gloss cannot be obtained. ..

The present inventors have stated that such blister generation is caused by the presence of a metal foil or a metal vapor deposition layer in which the gas generated during the curing reaction of the adhesive that adheres the label to the metal can is gas impermeable. We found that it was caused by the fact that it was not dissipated, and proposed a decorative can body that does not generate blister and has excellent mirror gloss by using an adhesive that does not generate such gas (Patent Document 3).
By the way, a mirror glossy label (laminated film) having a metal foil or a metal vapor-deposited layer together with a printing layer used for such a decorative can body is generally a printing film in which the back surface is printed on a resin film and a vapor-deposited layer. A vapor-deposited film having a After winding this once, it is cut to the size of the body of a metal can to make a single-wafer label. After covering the metal can body with this sheet-fed label, a finishing varnish layer is applied, and the finishing varnish layer and the adhesive are cured to form a decorative can body in which the metal can body is coated with a mirror gloss label. It is formed.

Japanese Unexamined Patent Publication No. 11-272172 Japanese Unexamined Patent Publication No. 2005-1676 WO2010 / 016503

The mirror glossy label requires two films, a printing film and a vapor-deposited film, which are laminated and manufactured, and a long-term aging process is required. Therefore, there are many manufacturing processes and production. I am not yet fully satisfied with the sex and economics.
In addition, when attaching a mirror glossy label to a metal can, both ends of the label need to be overlapped, and if two sheets of a printing film and a vapor-deposited film are joined as in the above mirror glossy label, this overcoat is used. Since four films are overlapped in the wrap part, the thickness is large, and in the neck-in processing performed after attaching the mirror gloss label, especially when the can body plate thickness is thin, the neck part near the overlap part is used. I sometimes occurred.

On the other hand, even if the printing layer and the vapor-deposited layer are formed on one base film as a mirror glossy film, the above problem cannot be easily solved. That is, in a single film having such a structure, the printed layer is exposed until it is attached to a metal can and a finishing varnish is applied. As a result, there is a risk that the printed image will be scratched in the manufacturing process, the peeled printing ink will contaminate the manufacturing equipment, or the gas generated from the printing ink when forming the vapor deposition layer will cause uneven vapor deposition. May occur. Therefore, a protective layer is required to protect the print layer. However, while preventing blocking between the adhesive layer and the protective layer when winding a long film, the adhesive layer in the overlapped portion when coated on a metal can. It is not easy to achieve both the proper adhesion of the protective layer and the protective layer.
It is also recognized that when the mirror label is used for a container filled with contents that require retort sterilization, there are problems such as whitening of the printed image and deterioration of the interlayer adhesion of the label, resulting in blister-like film swelling defects. rice field. In the present specification, the interlayer adhesion of the label means the adhesion between the adhesive layer and the protective layer in the overlapped portion.

Therefore, an object of the present invention is to have a beautiful mirror gloss, to enable proper adhesion at the overlap portion when attached to a metal can, and to effectively prevent wrinkles from being generated due to neck-in processing or the like. Is to provide a mirrored label.
Another object of the present invention is to provide a method capable of efficiently producing a mirror glossy label in which a printing layer and a vapor-deposited layer are formed on a single base film without causing the above-mentioned problems. ..
Still another object of the present invention is a mirror surface having retort resistance that does not cause whitening of the gravure printed image or deterioration of the interlayer adhesion of the label even when subjected to retort sterilization treatment, pastry sterilization, or the like. To provide a label.

According to the present invention, a gravure print image is formed on one surface of a metal layer-forming resin film in which a metal layer is formed on one surface of the resin film, and protection in a semi-cured state is formed so as to cover the gravure print image. An adhesive layer is formed on the other surface on which the layer is formed and the gravure print image of the metal layer-forming resin film is not formed , and the protective layer is a urethane isocyanate-based composition or a polycarbonate isocyanate-based composition. Mirror labels are provided characterized by consisting of any of the objects or a mixture thereof.
According to the present invention, a gravure print image is formed on one surface of the metal layer-forming resin film in which a metal layer is formed on one surface of the resin film, and a semi-cured state is formed so as to cover the gravure print image. An adhesive layer is formed on the other surface on which the protective layer is formed and the gravure print image of the metal layer-forming resin film is not formed, and the protective layer is located on the gravure print image side. It is a two-layered protective layer composed of a layer and an upper protective layer formed on the lower protective layer, and the upper protective layer is a polyester isocyanate-based composition, a urethane isocyanate-based composition, or a polycarbonate isocyanate-based. A mirror surface label is provided, which comprises any of the compositions, wherein the lower protective layer is composed of either an epoxy isocyanate-based composition or an epoxy amino-based resin composition.
In the mirror label of the present invention,
1 . A transparent resin film before Symbol resin film, the gravure printing image is formed on the resin film side of the metal layer forming resin film, said adhesive layer is formed on the metal layer side,
2 . The protective layer on at least one of the edges extending in the can height direction of the mirror surface label is 10 to 90% of the thickness of the protective layer in the other portion at a width of 0.5 to 10 mm from the edge. matter,
3 . The upper protective layer of the protective layer is made of a polyester isocyanate-based composition.
4 . The lower protective layer of the protective layer is made of an epoxy isocyanate-based composition.
5 . The base resin of the ink composition used for the gravure printing is an acrylic resin.
Is preferable.

According to the present invention, there is also provided a mirror surface label metal can having the mirror surface label attached to the mirror surface label, wherein a finishing varnish layer is formed on the mirror surface label. ..
Further, according to the present invention, after the mirror surface label is attached to the body of the metal can, a finish varnish is applied at least on the mirror surface label and cured to form a finish varnish layer. A method for manufacturing a featured mirror-labeled metal can is provided.

According to the present invention, further, a step of forming a gravure print image by gravure printing on one of the resin films on which a metal layer is formed, and forming a semi-cured protective layer so as to cover the gravure print image. to process, the step of forming the adhesive layer by applying an adhesive to the other surface of the gravure printing image is not formed of a resin film wherein the metal layer is formed, seen including, it said protective layer is a urethane isocyanate Provided is a method for producing a mirror surface label, which comprises any of a composition, a polycarbonate isocyanate-based composition, or a mixture thereof.
According to the present invention, a step of forming a gravure print image by gravure printing on one of the resin films on which a metal layer is formed, and forming a semi-cured protective layer so as to cover the gravure print image. The step includes a step of applying an adhesive to the other surface on which the gravure print image of the resin film on which the metal layer is formed is not formed to form an adhesive layer, and the protective layer is on the gravure print image side. It is a two-layered protective layer composed of a lower protective layer located in the lower protective layer and an upper protective layer formed on the lower protective layer, and the upper protective layer is a polyester isocyanate-based composition or a urethane isocyanate-based. Provided is a method for producing a mirror surface label, which comprises either a composition or a polycarbonate isocyanate-based composition, and the lower protective layer is composed of either an epoxy isocyanate-based composition or an epoxyamino-based resin composition. Will be done.
In the method for producing a mirror surface label of the present invention, in the step of forming the protective layer, the protective layer at at least one of the edges of the mirror surface label in the can height direction is 0.5 to 10 mm from the edge. In terms of width, it is preferable that the thickness is 10 to 90% of the thickness of the protective layer of the other portion.

Since the mirror surface label of the present invention has only one resin film even if it has a metal layer, it is a conventional mirror surface glossy label formed by laminating a film having a metal layer and a film having a printed image using an adhesive. Compared to this, it is easy and economical to manufacture, and the thickness of the label itself is thin, so the thickness of the overlapped part when attached to a metal can is reduced, and wrinkles are effectively generated during neck processing. It is prevented.
Further, since the protective layer is formed so as to cover the printed image, it is possible to protect the printed image in the manufacturing process, and the protective layer is maintained in a semi-cured state until it is attached to a metal can or the like. Therefore, the adhesive layer and the protective layer do not block when the long film is wound, and the label is wound around a metal can or the like and heated with the label ends overlapped to adhere to each other. The layer and the protective layer are cured in a state of being in close contact with each other, and the two are firmly bonded to each other, effectively preventing label adhesion failure (blister, peeling, or wrinkling) at the overlapped portion.
Further, as a protective layer, a resin composition comprising any one of an epoxy isocyanate-based composition, a urethane isocyanate-based composition, an acrylic isocyanate-based composition, a polycarbonate isocyanate-based composition, a polyester isocyanate-based composition, or a mixture of two or more thereof. When is used, it is possible to effectively prevent the generation of blister in the overlapping portion when the label is attached to the metal can, and also by reducing the thickness of the protective layer that becomes the overlapping portion. Can be effectively prevented and excellent mirror glossiness can be exhibited.

Further, by making the protective layer a two-layered protective layer consisting of a lower protective layer on the gravure print image side and an upper protective layer formed on the lower protective layer, the lower protective layer and the upper protective layer are formed. It is possible to form with a resin composition that matches the properties required for each of the labels, and even when applied under high temperature and high humidity conditions such as retort sterilization, the interlayer adhesion of the label is reduced and gravure printing is performed. It is possible to effectively prevent whitening of the image.
In particular, by forming the lower protective layer with an epoxy isocyanate-based composition having excellent moisture barrier properties, the amount of moisture reaching the gravure printed image can be reduced, whitening of the gravure printed image can be prevented, and the upper protective layer can be formed. By forming the polyester isocyanate-based composition having excellent adhesiveness to the adhesive layer, the interlayer adhesion after retorting can be improved, and the retort resistance is remarkably improved.
Further, by using an acrylic resin as the base resin of the ink composition used for gravure printing, whitening of the gravure printed image can be prevented, so that the retort resistance is improved.
In addition, the "retort resistance" in the present specification means not only the retort sterilization treatment but also the interlayer adhesion after sterilization and the whitening of the gravure printed image even when it is subjected to other high temperature sterilization treatments such as pastryse sterilization. It means that it can be prevented.

The above-mentioned action and effect of the present invention are also clear from the comparison of the results of Examples and Comparative Examples described later.
That is, in a mirror label formed by joining two sheets of a resin film having a metal layer and a resin film on which a printed image is formed, wrinkles occur in the neck portion when the neck is processed after being attached to a metal can ( Comparative Example 1), or if the protective layer is not formed, blocking or the printed image will be damaged in the manufacturing process (Comparative Example 2). Furthermore, if the finished varnish layer is not formed after the mirror label is attached to the metal can, sufficient gloss is not obtained and the appearance characteristics are inferior (Comparative Example 3).
On the other hand, in the mirror surface label (Examples 1 to 16) of the present invention, blocking is effectively prevented even in a long state wound on a roll. In addition, even when it is attached to the body of a metal can, the printed image is not scratched, there is no blister, peeling, or wrinkles on the overlapped part, and it has excellent mirror gloss. it is obvious.
Further, in a metal can having a two-layered protective layer formed by combining a lower protective layer made of an epoxy isocyanate-based composition and an upper protective layer made of a polyester isocyanate-based composition, each evaluation result before retort sterilization is excellent. Of course, it is clear that the generation of blister in the overlapped portion after retort sterilization is effectively prevented (Examples 13 and 14). Further, it is clear that whitening of the printed image can be prevented by using an acrylic resin as the base resin of the ink composition used for gravure printing (Examples 13 and 16).

It is a figure which shows the layer structure of the mirror surface label of this invention. It is a figure which shows another example of the layer structure of the mirror surface label of this invention. It is a figure which shows another example of the layer structure of the mirror surface label of this invention. It is a figure explaining the cross-sectional structure of the overlap part of the metal can of this invention. It is a figure explaining the cross-sectional structure of the overlap part of the metal can using the mirror surface label shown in FIG. It is a figure which shows the layer structure of the metal can to which the mirror surface label shown in FIG. 1 was attached.

(Mirror label)
[Layer structure]
The layer structure of the mirror label of the present invention will be described with reference to FIGS. 1, 2 and 3.
As shown in FIG. 1, in the mirror surface label of the present invention whose whole is shown by 1, a resin film 10 is used as a base film, and a printed image 11 by gravure printing is formed on one surface of the resin film 10, and further. A semi-cured protective layer 12 is provided so as to cover the printed image 11. Further, on the other surface of the resin film 10, a metal layer 13 made of a metal vapor deposition layer or a metal foil, which will be described later, is formed, and an adhesive layer 14 is further formed on the metal layer 13.
Further, in the mirror surface label of another aspect of the present invention shown in FIG. 2, a metal layer 13 made of a metal vapor deposition layer or a metal foil is formed on one surface of the resin film 10, and gravure printing is performed on the metal layer 13. A printed image 11 is formed, and a semi-cured protective layer 12 is provided so as to cover the printed image 11. Further, the adhesive layer 14 is formed on the other surface of the resin film 10.
Further, in the mirror surface label of another aspect of the present invention shown in FIG. 3, the protective layer 12 is formed on the lower protective layer 12a and the lower protective layer 12a so as to cover the printed image 11 by gravure printing. It has a two-layer structure of the upper protective layer 12b in a semi-cured state formed in.
All of these mirror labels are attached so that the gravure print image side is the outer surface side and the adhesive layer 14 side is the metal can side.

[Resin film]
The resin film to be the base film of the mirror surface label of the present invention is a thermoplastic resin known per se, for example, low density polyethylene, high density polyethylene, polypropylene, poly 1-butene, poly 4-methyl-1-pentene or ethylene. Random or block copolymers of α-olefins such as propylene, 1-butene, 4-methyl-1-pentene, and olefin-based resins such as cyclic olefin copolymers; ethylene / vinyl acetate copolymers, ethylene / Ethylene-vinyl copolymer resin such as vinyl alcohol copolymer, ethylene / vinyl chloride copolymer; styrene resin such as polystyrene, acrylonitrile / styrene copolymer, ABS, α-methylstyrene / styrene copolymer; Vinyl-based resins such as polyvinyl chloride, polyvinylidene chloride, vinyl chloride / vinylidene chloride copolymer, methyl polyacrylate, polymethyl methacrylate, etc .; nylon 6, nylon 6-6, nylon 6-10, nylon 11, nylon 12 Such as amide resin; polyester resin such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate; polycarbonate; polyphenylene oxide; biodegradable resin such as polylactic acid; and the like.
The resin film 10 is not limited to this, but is preferably transparent.
In general, it has excellent transparency and at the same time has good heat resistance to heat treatment for heat curing performed when manufacturing this mirror surface label, and further, a semi-cured state of the protective layer. A polyester resin such as polyethylene terephthalate is preferably used in that it is insoluble in the organic solvent used for determining (this point will be described later).

The thickness of the resin film is not particularly limited, but if it is excessively thick, the mirror surface label will be thicker than necessary, and when the label is attached to a metal can, the thickness of the overlap portion will be thicker, and neck wrinkles due to neck-in processing will occur. May occur and the appearance of the metal can may be impaired. The specific thickness cannot be unconditionally specified because it varies depending on the size of the metal can and the like, but in the case of a general metal can for beverages, the thickness of the resin film is about 8 to 20 μm. The resin film may be uniaxially or biaxially stretched, and particularly biaxially stretched ones can be preferably used.

[Metal layer]
In the mirror surface label of the present invention, a metal layer is formed on one surface of the resin film. Examples of the metal layer include a metal vapor deposition layer and a metal foil such as an aluminum foil.
The metal vapor deposition layer is formed by depositing a metal on the above-mentioned resin film by a conventionally known method such as a vacuum vapor deposition method. Examples of the metal used for the thin-film deposition layer include aluminum, copper, chrome, and silver. Among them, aluminum, copper, chrome, silver, and the like have a decorative effect of having a silver-like metallic color and excellent mirror gloss, and are cost effective and versatile. From the point of view, aluminum is most preferably used.
The thickness of the thin-film deposition layer is preferably in the range of 200 to 800 Å, preferably in the range of 300 to 600 Å. If the thickness of the thin-film deposition layer is less than 200 Å, sufficient mirror gloss cannot be obtained and the hiding power is inferior. ..
Further, as the metal foil, in addition to the aluminum foil, a simple substance such as copper, silver, zinc, nickel or the like or a thin alloy can be used. The thickness of the metal foil is about 3 to 10 μm, and it is laminated on the resin film via an adhesive layer.

[Gravure print image]
In the present invention, the printed image formed on the resin film or the metal layer formed on the resin film is formed by gravure printing which can be printed in large quantities at high speed and can be printed in rich color and beautifully. NS. Conventionally known inks can be used as the ink for gravure printing, and specifically, thermosetting inks using a thermosetting resin such as acrylic, urethane, or polyester as a base resin can be preferably used. can. When a urethane resin is used as the base resin, it is preferable to blend a vinyl chloride-vinyl acetate copolymer resin.
In particular, when the mirror label of the present invention is used in a container filled with contents that require retort sterilization treatment, it is possible to use an ink composition using an acrylic resin as a base resin that can improve retort resistance. desirable. That is, since the acrylic resin has high hydrophilicity, it is considered that even when water invades by the retort sterilization treatment, the water is suppressed from becoming bubbles and whitening of the printed image can be effectively prevented.
Even if whitening occurs in the dark-colored printed image, it is not noticeable and its existence is not recognized. Therefore, for the transparent or light-colored printed image, a printing ink composition using an acrylic resin as a base resin is used. In other parts, a printing ink composition using a urethane resin or the like as a base resin can be used, and the base resin can be changed depending on the color of the ink.

The gravure printing ink may contain a metal powder pigment such as aluminum powder, silver powder, or copper powder, or a pearl pigment obtained by coating the surface of thin plate-shaped mica particles with titanium dioxide, iron oxide, or the like. This makes it possible to further improve the decorativeness. Conventionally known metal powder pigments, pearl pigments, and the like can be used, but those having a particle size in the range of a maximum of 100 nm are preferably used.
Further, a transparent anchor coat layer may be formed on the resin film prior to gravure printing. As the anchor coat layer, a conventionally known one can be used. For example, a coating liquid obtained by dispersing or dissolving a thermosetting acrylic resin, an epoxy resin, a polyurethane resin or the like in a predetermined solvent is applied and dried. It can then be formed by heating. The thickness of the anchor coat layer is usually about 0.1 to 2.0 μm.

[Protective layer]
It is important that the protective layer formed to protect the gravure printed image is kept in a semi-cured state in the state of the label, and also an epoxy isocyanate-based composition, a urethane isocyanate-based composition, and an acrylic isocyanate-based composition. It is preferably composed of any one of a composition, a polycarbonate isocyanate-based composition, a polyester isocyanate-based composition, or a mixture of two or more thereof. The protective layer is preferably colorless and transparent.
That is, any one of an epoxy isocyanate-based composition, a urethane isocyanate-based composition, an acrylic isocyanate-based composition, a polycarbonate isocyanate-based composition, and a polyester isocyanate-based composition used for forming a protective layer, or two or more of these. Since the mixture in the above produces less gas in the curing reaction and gradually releases the gas even during storage at room temperature, blister may be generated in the overlapped portion when it is attached to a metal can. It can be effectively prevented.
Further, since the protective layer is adhered to the adhesive layer of the label at the overlapping portion, in order to improve the adhesiveness between the labels, a resin made of the same type as the resin forming the adhesive layer should be selected. For example, when a polyester isocyanate-based adhesive composition described later is used as the adhesive layer, the protective layer is also made of the polyester isocyanate-based composition, so that the retort resistance is improved.

Lubricants such as paraffin wax, polyethylene wax, and silicon wax can be blended in the resin composition constituting the protective layer in the range of 0.005 to 5% by weight, whereby the resin composition is wound into a long shape. The effect of preventing blocking with the adhesive layer can be improved even when the mirror surface labels cut according to the size of the metal can are stacked and stored in a state or after being wound up.

In addition, it is important that the protective layer is in a semi-cured state in the state of the label for the following reasons. That is, as shown in FIG. 4 or 5, the mirror surface label 1 sown on the body of the metal can 20 has a protective layer 12 (upper protective layer 12b in FIG. 5) and an adhesive layer 14 at the overlap portion X. In the contacted state, the adhesive layer 14 is thermally cured to adhere the label 1 to the metal can 20, but when the protective layer 12 is completely cured, the protective layer 12 and the adhesive layer 14 are adhered to each other. This is not possible, and the label is peeled off at the overlap portion X, which significantly reduces the commercial value of the metal can.
On the other hand, in the present invention, since the protective layer 12 is held in the semi-cured state in the state of the label, the protective layer 12 can be cured at the same time as the heat curing of the adhesive layer 14, so that the overlapping portion X Then, a cross-linking bond is formed between the two to firmly bond them, and it is possible to effectively prevent the occurrence of label peeling as described above.

The semi-cured state of the protective layer can be evaluated by the EtOH rubbing method using ethyl alcohol (EtOH) as a solvent, as shown in Examples described later. This evaluation value is displayed by the number of rubbing performed in a state where the semi-cured product is moistened with EtOH. The larger this value is, the more the curing is progressing, and the smaller this value is, the more the uncured state is. Is shown. In the present invention, it is preferable that this value is in the range of 5 to 90 times. That is, if this value is too large, the curing progresses too much, and it becomes difficult to bond the protective layer and the adhesive layer at the time of sticking to the metal can, and the space between the labels at the overlap portion X becomes difficult. It becomes difficult to prevent peeling. On the other hand, if the evaluation value is smaller than the above range, the curing becomes insufficient and the protective layer becomes sticky, and when it is wound into a long shape or after being wound, it becomes the size of a metal can. When the single-wafer labels cut together are stacked and stored, they may be blocked, and the protective layer or adhesive layer may be partially peeled off, resulting in insufficient decorativeness or poor adhesion to metal cans. be.
The protective layer in the semi-cured state is formed when the coated layer of the resin composition coated so as to cover the printed image is not completely cured and the adhesive layer is formed first. Heat treatment at low temperature for a short time so as not to cure the adhesive layer, specifically, a method of semi-curing at 40 ° C. to 200 ° C. for about 1 to 300 seconds, or a curing agent for the main agent of the protective layer resin composition. It can be carried out by a method of reducing the ratio of the above to a semi-cured state.

The thickness of the protective layer in such a semi-cured state is usually about 0.1 to 10 μm, particularly 0.4 to 10 μm, for the thickness of the covering portion existing on the printed image (usually about 0.1 to 10 μm). It is better to set it to about 5 μm. If this thickness is too thin, the protective performance of the protective layer will be low, and if it is made thicker than necessary, it will only increase the cost.
Further, particularly when the mirror surface label of the present invention is used for a metal can, the thickness of the protective layer of the portion constituting the overlap portion is compared with that of other portions in order to reduce the thickness of the label in the overlap portion. It is preferable to make it thinner.
That is, in the present invention, the protective layer is any one of an epoxy isocyanate-based composition, a urethane isocyanate-based composition, an acrylic isocyanate-based composition, a polycarbonate isocyanate-based composition, a polyester isocyanate-based composition, or two or more of these. Although the mixture is used in a semi-cured state, these compositions generate a small amount of gas during curing. Therefore, by reducing the thickness of the protective layer at the overlapping portion, gas is generated. It is desirable to reduce the amount and make it easier for gas to escape.

The thickness of the protective layer is reduced by at least one edge in the can height direction of the label that is the overlap portion, and in particular, the thickness of one edge that is the container side of the overlap portion is thin. desirable. In the case of a general metal can, it is preferable to reduce the thickness of the protective layer at least in a portion having a width of 0.5 to 10 mm, and the thickness thereof is 10 to 90% of the thickness of the protective layer other than the overlap portion. Is preferable.
Further, it is preferable that the surface roughness (Ra) of the protective layer is 0.2 μm or less due to the arithmetic mean roughness. That is, the glossiness of the label can be improved by smoothing the unevenness due to the gravure print image by the protective layer, and the glossiness of the metal can body after the finishing varnish is provided is also improved, and the mirror surface by the metal layer is improved. Combined with gloss, it is possible to provide labels with excellent design.
Further, an anti-blocking agent can be added to the protective layer as long as the transparency of the protective layer is not impaired. This makes it possible to prevent blocking with the adhesive layer when the product is wound into a roll.
Examples of such anti-blocking agents include conventionally known inorganic anti-blocking agents such as silica-based, calcium carbonate-based, alumina-based, silica-alumina-based, titanium-based, clay-based, and zeolite-based, crosslinked polystyrene particles, and crosslinked polyacrylate particles. Examples of organic antiblocking agents such as crosslinked resin particles such as those having an average particle size of 0.1 to 10 μm can be contained in an amount of 0.1 to 50% by weight.

In the present invention, between the above-mentioned protective layer (hereinafter referred to as "upper protective layer") and the gravure printed image, another protective layer (hereinafter referred to as "lower protective layer") is provided so as to cover the gravure printed image. Can also be formed. As a result, in combination with the presence of the upper protective layer, the protection of the gravure printed image is more reliable, the thickness of the upper protective layer can be reduced, and the generation of blister in the overlapped portion is further suppressed. Will be possible.
The resin constituting such a lower protective layer is not particularly limited, and various resins can be used, and the resin is not limited to this, but is the same as the epoxy amino resin composition or the above-mentioned protective layer. In particular, an epoxy isocyanate-based resin composition can be exemplified.
Further, the upper protective layer needs to be in a semi-cured state in the state of a label, but the degree of curing of the lower protective layer is not particularly limited. It is preferable that the EtOH rubbing is 100 times or more, and the cured state is more than the EtOH rubbing times of the upper protective layer. As a result, the thickness of the upper protective layer in the semi-cured state can be reduced, and the generation of blister in the overlapped portion can be further suppressed. Further, when the upper protective layer is in the semi-cured state where the number of EtOH rubbing is small, the lower protective layer is in the cured state, so that the gravure printed image can be effectively protected.

The thickness of the lower protective layer is the same as that of the case where only the upper protective layer is provided, that is, the thickness of the entire protective layer combined with the upper protective layer is about 0.1 to 10 μm, particularly about 0.4 to 5 μm. The thickness is preferably set, and the thickness ratio between the upper protective layer and the lower protective layer is preferably in the range of 80:20 to 20:80.
The lower protective layer may be partially formed so as to cover only the portion where the gravure printed image is formed, for example, but it is preferably a layer (solid layer) that uniformly covers the entire layer.
Further, since the lower protective layer is formed on the gravure printed image, it is preferable that the lower protective layer is transparent and colorless in order to ensure the sharpness of the image.
When the mirror label of the present invention is used in a container filled with contents requiring retort sterilization treatment, as described above, the upper protective layer is made of a polyester isocyanate-based composition and the lower protective layer is an epoxy isocyanate-based composition. It is desirable to consist of a composition.

[Adhesive layer]
The adhesive layer is a layer provided for attaching the mirror label of the present invention to a metal can or the like, and is a specific example shown on the surface of the metal can or the like by heating and pressurizing, for example, FIGS. 4, 5 and 6. Then, a mirror label is attached to the resin coating layer 20b on the metal plate 20a constituting the metal can 20. In the present invention, as the adhesive resin (adhesive) forming the adhesive layer, a polyester isocyanate-based adhesive composition, particularly one in which a polyisocyanate having an internal block type as a curing agent component is used can be preferably used. ..
That is, in a mirror label in which a metal layer is indispensable for imparting mirror gloss, since the metal layer is formed on one surface of the resin film, if an adhesive resin that releases gas during heat curing is used, it adheres. The gas generated when the layer is heat-cured and attached to the body of the metal can is blocked by the metal layer and is not discharged to the outside of the label, so that the mirrored label is partially removed from the surface of the body of the metal can. A blister phenomenon that floats up may occur.
Therefore, in the present invention, a gas-non-releasing polyester isocyanate-based adhesive resin in which a thermosetting polyester resin is used as a thermosetting resin component and an internal block type polyisocyanate is used as a curing agent component is used. do. In this gas-non-releasing polyester isocyanate-based adhesive resin, an internal block-type isocyanate used as a curing agent is formed by a reaction between isocyanate groups to form uretdione groups and uretoimine groups, whereby the isocyanates are blocked and cured. The stability in front can be ensured. That is, when the internal block type isocyanate is used as a curing agent component, the isocyanate groups are blocked (internal block) by the mutual reaction between the polyisocyanates, so that they are formed by the mutual reaction of the isocyanate groups by heat curing. The uretdione group and the uretoimine group dissociate into the isocyanate group and do not generate the low molecular weight compound that is the cause of gas generation. Therefore, the blister phenomenon due to the generation of gas as described above can be effectively prevented.

The internal block type polyisocyanate as described above is known by itself, and for example, JP-A-2005-154443, JP-A-2006-169243 and the like disclose its manufacturing method and the like. The thermosetting resin containing the internal block type polyisocyanate is commercially available by Toyobo Co., Ltd. under the trade name of Byron 670.
The adhesive layer is formed by applying an adhesive solution obtained by dispersing or dissolving such a gas-free polyester isocyanate-based adhesive resin in various solvents by roller coating or the like and drying the adhesive layer. The thickness of the adhesive layer is preferably in the range of 1 to 10 μm.
Further, it is preferable that the adhesive layer contains a pigment such as titanium oxide. Since the adhesive layer contains a pigment, it is possible to effectively prevent heat shrinkage of the adhesive layer when the mirror label is wrapped around the body of a metal can and attached by heating, and a printed image due to heat shrinkage. Distortion and the like can be effectively prevented. Such pigments are preferably contained in the adhesive layer in an amount of 10 to 90% by weight.

[Other layers]
The mirror surface label of the present invention has the above-mentioned layer structure as a basic structure, but other layers may be added in order to improve the decorativeness of the mirror surface label.
For example, a hologram pattern can be formed between the above-mentioned gravure printed image and the metal layer, whereby the metallic luster and the mirror surface label of the printed image can be synergistically decorated with a three-dimensional decorative effect. can.
The hologram pattern can be formed by a conventionally known method, and in the present invention, it may be formed on either the surface of the resin film on which the gravure printed image is formed or the surface on which the metal layer is formed.
Further, it may have an inkjet print image together with the gravure print image, and may be formed either after or before the formation of the gravure print image.
Further, a pigment-containing paint layer such as a bright pigment or a white coat layer can be formed entirely or partially between the metal layer and the gravure print image to improve the decorativeness of the gravure print image. Especially when there are characters in gravure printing, the characters can be made clearer by forming a white coat layer.

[Manufacturing method of mirror label]
The mirror surface label of the present invention having the above-mentioned layer structure is a step of forming a gravure print image by gravure printing on one of the base resin films on which a metal layer is formed, and a protective layer so as to cover the gravure print image. It can be manufactured by a manufacturing method including at least a step of forming an adhesive layer and a step of applying an adhesive to the other surface on which the gravure print image of the resin film on which the metal layer is formed is not formed. It is preferable to form each layer in this order, but it can be appropriately changed as long as it does not adversely affect the formation of other layers.
That is, a resin film having the above-mentioned metal layer formed on one surface of the resin film is prepared. When the metal layer is a metal vapor deposition layer, the metal vapor deposition layer is directly formed on the resin film by a conventionally known vapor deposition method, and when the metal layer is a metal foil such as aluminum foil, the resin film is formed via an adhesive layer. Laminate metal foil and the like. For the adhesion between the metal foil and the resin film, conventionally known adhesives such as urethane-based adhesives, epoxy-based adhesives, and acid-modified olefin-based adhesives can be used.
The resin film may be subjected to a conventionally known surface treatment such as corona treatment or plasma treatment prior to the formation of the metal layer or gravure printing.

Next, gravure printing is performed on one surface of the resin film on which the metal layer is laminated, preferably on the resin film side, and then the printed image is dried or cured.
Any one of epoxy isocyanate-based composition, urethane isocyanate-based composition, acrylic isocyanate-based composition, polycarbonate isocyanate-based composition, polyester isocyanate-based composition, or a mixture of two or more thereof on the formed gravure printed image. Form a protective layer consisting of. It is important that the protective layer is in a semi-cured state at least when it is wound into a roll, and the protective layer may be heated and dried immediately after being applied with the resin composition forming the protective layer to be in a semi-cured state. However, it is also possible to make the adhesive layer semi-cured at the same time as heating and drying.
The semi-cured protective layer can be formed by heat treatment at a low temperature in a short time, specifically, by semi-curing at 40 to 200 ° C. for about 1 to 300 seconds.
In the mirror surface label of the present invention, as described above, the amount of gas released from the resin composition forming the protective layer is reduced, the release thereof is facilitated, and the increase in thickness at the overlap portion is reduced. Therefore, the thickness of the protective layer of at least one edge, specifically, the edge having a width of 0.5 to 10 mm in the case of a metal can, which is the overlapping portion of the mirror surface label, is 10 as compared with the other portion. It is desirable to adjust the coating amount so as to reduce the thickness by ~ 90%.

Further, it is preferable to prepare a mirror label by applying and drying a non-gassing polyester isocyanate-based adhesive composition constituting the adhesive layer on a metal layer or a resin film on the opposite side of the protective layer.
When applying the polyester isocyanate adhesive composition, use an ester solvent such as ethyl acetate and butyl acetate, a ketone solvent such as acetone and methyl ethyl ketone, and a solvent such as aromatic hydrocarbons such as toluene and xylene. Can be done.
The thickness of the adhesive layer is generally preferably in the range of 1 to 6 μm, particularly preferably 2 to 5 μm.

The mirror label of the present invention generally uses a roll-shaped resin film, and as described above, a metal layer, a gravure printed image, a protective layer, and an adhesive layer are formed and then wound up in a roll shape. In, since the protective layer is held in a semi-cured state, the protective layer and the adhesive layer do not block even if they are wound into a roll.
The long label wound into a roll shape thus produced is unwound when attached to a metal can or the like, cut into a blank shape of an appropriate size, and is a mirror surface label of the present invention. Completed as.

(Container to which a mirror label is attached)
The mirror label of the present invention can be used not only for metal cans, which will be described later, but also for plastic containers, pouches and the like.
Conventionally known plastic containers and pouches can be used without limitation, and the plastic container is not limited to this, but is a hollow container made by extrusion blow molding or injection blow molding of an olefin resin such as polyethylene or polypropylene. Examples of conventionally known plastic containers such as a biaxially stretched blow-molded bottle made of a polyester resin such as polyethylene terephthalate, or a cup-shaped container made by vacuum-molding a sheet made of a thermoplastic resin can be exemplified, in the case of a metal can. Similarly, it can be used by being attached to these bodies.
The pouch is not limited to a conventionally known pouch, for example, a pouch formed by heat-sealing a laminate such as an inner layer made of a heat-sealing resin / an oxygen-blocking intermediate layer such as aluminum foil / an outer layer made of a stretched plastic resin. It can be used, in which case it can be used by attaching a mirror label to the side surface of the pouch.

(Mirror label metal can)
The mirrored label of the present invention can be particularly suitably used as a label for a metal can, is wrapped around the body of a metal can (heated if necessary), heated to a predetermined temperature with the ends overlapped, and then heated to a predetermined temperature. By curing the adhesive layer and the semi-cured protective layer, it is attached to the surface of the body of the metal can. In the mirror surface label of the present invention, since the protective layer is attached to the metal can while being held in the semi-cured state, both layers are firmly fixed by curing the adhesive layer and the protective layer at the overlapping portion. It can be adhesively fixed and peeling off at the overlapped portion is effectively prevented.
FIG. 6 is a diagram showing a cross-sectional structure of an example of the mirror surface label metal can of the present invention, and the metal can 30 to which the mirror surface label of the present invention is attached is a resin coating layer 20b on a metal plate 20a constituting the metal can. The adhesive layer 14 of the mirror label is located above, and the finishing varnish layer 21 is formed on the protective layer 12. The mirror-labeled metal can on which the finishing varnish layer is formed is completed by being subjected to neck-in processing and flange processing.
By forming the finishing varnish layer, the mirror glossiness of the mirror surface label stands out, and the decorativeness is further improved.

As the finishing varnish, thermosetting resin such as polyester resin, acrylic resin and epoxy resin, and as a curing agent, amino resin such as melamine, phenol resin, isocyanate resin and the like are used at 0.1 to 10 parts by weight of the thermosetting resin. Conventionally known finishing varnish, which is contained in an amount of about a part by weight, can be used.
Further, as the finishing varnish, a lubricant such as paraffin wax, polyethylene wax, silicon wax and the like may be blended in an amount of 0.1 to 3% by weight.
The thickness of the finishing varnish layer is preferably in the range of 0.1 to 10 μm, particularly 0.5 to 5 μm.
The formation of the finishing varnish layer is generally carried out by heating at a temperature of 170 to 230 ° C. for 0.5 to 2 minutes.

The metal can to which the mirror surface label of the present invention is attached is not particularly limited, and various metal plates such as aluminum plates, aluminum alloy plates, surface-treated steel plates such as tin-free steel, tin plates, chrome-plated steel plates, and aluminum-plated steel plates are used. , Nickel-plated steel plate, tin nickel-plated steel plate, and other various alloy-plated steel plates, seamless cans formed by drawing, squeezing, re-drawing, bending and stretching (stretch draw processing), welded cans, etc. Various types of metal cans are used. Further, the metal plate may be a resin-coated metal plate having a surface coated with a resin film such as a polyester film, a nylon film, or a polypropylene film, and is particularly obtained by a harsh molding process such as a seamless can. Then, it is preferable to use a resin-coated metal plate. Further, in the case of steel cans, a white pigment such as titanium oxide may be blended in this resin coating.

The present invention will be described with reference to the following experimental examples.
In the evaluation of the mirror-labeled metal can (hereinafter, may be referred to as a mirror-labeled can), the mirror-surfaced label obtained in the examples can be used for the can body including the neck corresponding portion of the seamless can with a diameter of 52.5 mm. After sticking to, the diameter was reduced to 50.5 mm by single-neck die-neck processing, and then flange-processed was used. The seamless can was formed by laminating a thermoplastic polyethylene terephthalate resin on both sides of an electrolytic chromic acid-treated steel sheet having a plate thickness of 0.185 mm and performing a known stretch draw process.

(Evaluation method and measurement method)
<Evaluation of coil blocking property>
The prepared long coil was once wound up, unwound, and then the surface of the coil was visually inspected to evaluate the blocking property. The evaluated blocking means that the protective layer (gravure printed image in Comparative Example 2) and the adhesive layer adhere to each other when the coil is wound, so that a part of the layer is peeled off and adhered to another layer when the coil is unwound. It is a defect that becomes a state.
The area equivalent to 1000 can blanks was evaluated according to the following criteria.
◯: No peeling on blanks equivalent to all cans.
Δ: Peeling with a diameter of less than 0.5 mm is less than a blank equivalent to 10 cans. It is within the permissible range as a product.
X: Peeling with a diameter of less than 0.5 mm is in the blank equivalent to 10 cans or more, or peeling with a diameter of 0.5 mm or more is in the blank equivalent to 1 can or more.

<Evaluation of print image scratches>
The printed image of 1000 mirror-labeled cans was visually inspected for scratches. The scratches were evaluated as scraping (peeling) of the printed image due to rubbing between the transport guide and the can body.
◯: No scratches (printed image peeling) on all cans.
Δ: There are scratches (printed image peeling) with a diameter of less than 0.5 mm in less than 10 cans. It is within the permissible range as a product.
X: There are scratches (printed image peeling) with a diameter of less than 0.5 mm in 10 cans or more, or scratches with a diameter of 0.5 mm or more (printed image peeling) in 1 can or more.

<Evaluation of blister on the processing overlap>
The overlap portion (OL portion) of the obtained mirror-finished label can that had been die-necked was visually observed. When the adhesion between the protective layer and the adhesive layer is insufficient and peeling occurs between the films due to the die neck processing, it is observed as a blister-like film swelling defect in the neck portion. 1000 mirror-labeled cans were evaluated.
○: No swelling in all cans.
Δ: There is a swelling with a diameter of less than 0.5 mm in less than 10 cans. It is within the permissible range as a product.
X: There are swellings with a diameter of less than 0.5 mm in 10 cans or more, or swellings with a diameter of 0.5 mm or more in 1 can or more.

<Evaluation of can body overlap part blister>
The overlapping portion (OL portion) of the obtained mirror surface label can body was visually observed. When gas is generated during curing of the protective layer composition or the adhesive layer resin of the overlapping portion sandwiched between the metal layers, it is observed as a blister-like film swelling defect in the OL portion of the can body. 1000 mirror-labeled cans were evaluated.
○: No swelling in all cans.
Δ: There is a swelling with a diameter of less than 0.5 mm in less than 10 cans. It is within the permissible range as a product.
X: There are swellings with a diameter of less than 0.5 mm in 10 cans or more, or swellings with a diameter of 0.5 mm or more in 1 can or more.

<Evaluation of overlapping neck wrinkles>
With respect to the obtained 10 mirror-surfaced label cans, the degree of neck wrinkles in the overlap portion (OL portion) was visually observed from the appearance.
◯: There are no obvious neck wrinkles on all cans.
Δ: There are very few neck wrinkles in one can or less. It is within the permissible range as a product.
X: There are obvious neck wrinkles in one or more cans, or very slight neck wrinkles in two or more cans.

<Evaluation of can body gloss>
The body of the obtained mirror label can was cut out, and the glossiness of the outer surface was evaluated with a gloss meter (IG-410 manufactured by HORIBA).
◯: Gross is 70 or more.
Δ: Gross is 40 or more and less than 70.
X: Gross is less than 40.

<Measurement of degree of curing of protective layer>
For the obtained mirror surface label, the degree of curing of the protective layer was measured as follows. Cover the tip of a patterned hammer weighing 1 kg with gauze, infiltrate the gauze with ethyl alcohol (EtOH), hold the hammer in one hand, apply a damp gauze part to the outer surface of the protective layer, and keep a distance of 10 cm at a constant speed. I made it go back and forth. The speed was one round trip per second. The number of round trips until the protective layer was peeled off was counted and used as the number of rubbing.

<Evaluation after retort sterilization>
The obtained mirror-finished label can was filled with water, the lid was double-wound, and the three cans were tied together to bring the cans into contact with each other, and a steam-type static retort treatment was performed under the condition of 130 ° C. for 30 minutes. After that, it was cooled.
The obtained retort-treated mirror-surfaced label can was evaluated by the method described in the above [Evaluation of processed overlap portion blister].
In addition, the degree of whitening of the transparent gravure ink portion at the contact portion between the cans of the obtained retort-treated mirror label can was evaluated by visual inspection. The scores were based on the following criteria.
◯: No whitening Δ: There is slight whitening, but it is within the product allowable range.
X: Whitening is large and out of the product allowable range.

(Example 1)
<Making a mirror label>
An aluminum-deposited layer (thickness 500 Å) was formed on one side of a long transparent biaxially stretched polyethylene terephthalate film (PET film) having a thickness of 12 μm, and a printed image was formed on the other side by gravure printing and dried. At this time, the gravure printed image was formed not only in the center corresponding part of the can body of the can but also in the overlapping corresponding part. The gravure printing ink used was a blend of a urethane resin and a vinyl chloride-vinyl acetate copolymer resin as a base resin. Subsequently, the composition for forming a protective layer, in which an isocyanate-based curing agent was blended with an epoxy resin and polyethylene wax was blended in an amount of 0.5% by weight, was placed on a gravure printed image with a thickness corresponding to the center of the can blank. After coating so that the thickness of the lower film edge corresponding to the can blank overlap is 0 μm and the thickness is 2.0 μm, it is baked in a hot air blowing type heating oven at 130 ° C for 8 seconds. This was done to form a semi-cured protective layer. Next, an adhesive containing an isocyanate-based curing agent and titanium oxide (50% by weight in the dry resin) mixed with a polyester-based resin was coated on the metal-deposited layer with a gravure coater to a thickness of 5 μm, and at 130 ° C. × 8 seconds. After drying, it was wound as a coil with a take-up roller.

<Making mirror-labeled metal cans>
After unwinding the long label prepared above, cut it according to the size of the metal can to make a single-wafer mirror surface label, and wind it while applying pressure to the outer surface of the seamless can heated to 160 ° C. The overlapping portions were adhered by overlapping both ends of the mirror label, and the protective layer and the adhesive were baked and cured by baking at 200 ° C. for 1 minute in an oven. Next, a finishing varnish made by blending an amino-based curing agent with an epoxy resin was applied and baked and cured at 215 ° C. × 80 seconds to form a finishing varnish layer. Then, the opening side was necked and then flanged to produce a mirror-labeled metal can. The width of the overlap portion was set to 5 mm. The internal volume of the seamless can was 200 ml. The above-mentioned evaluation was performed on the obtained mirror surface label and mirror surface label metal can.
Table 1 shows the specifications of the mirror surface label, the specifications of the protective layer, the metal can specifications, the coil blocking property evaluation result, and the can body evaluation results obtained as described above.

(Example 2)
A mirror label and a mirror label metal can were prepared and evaluated in the same manner as in Example 1 except that wax was not added to the protective layer forming composition. The results are shown in Table 1.

(Example 3)
A mirror label and a mirror label metal can were produced in the same manner as in Example 1 except that the urethane isocyanate-based composition was used instead of the epoxy isocyanate-based composition of Example 1 as the protective layer forming composition. Evaluation was performed. The results are shown in Table 1.

(Example 4)
A mirror label and a mirror label metal can were produced and evaluated in the same manner as in Example 1 except that the thickness of the overlapping portion of the protective layer was 100% of the other portions (that is, solid coating). The results are shown in Table 1.

(Example 5)
A mirror label and a mirror label metal can were produced and evaluated in the same manner as in Example 1 except that the thickness of the overlapping portion of the protective layer was set to 10% of the other portions. The results are shown in Table 1.

(Example 6)
A mirror label and a mirror label metal can were produced and evaluated in the same manner as in Example 1 except that the degree of curing of the protective layer (degree of semi-cured state) was 90 times for EtOH rubbing. The results are shown in Table 1.

(Example 7)
A mirror label and a mirror label metal can were produced and evaluated in the same manner as in Example 1 except that the degree of curing of the protective layer (degree of semi-cured state) was set to 5 times for EtOH rubbing. The results are shown in Table 1.

(Example 8)
A mirror label and a mirror label metal can were produced in the same manner as in Example 1 except that the polycarbonate isocyanate-based composition was used instead of the epoxy isocyanate-based composition of Example 1 as the composition for forming the protective layer. Evaluation was performed. The results are shown in Table 1.

(Example 9)
As the metal layer, a mirror surface label and a mirror surface label metal can were produced in the same manner as in Example 1 except that an aluminum foil (thickness 7 μm) was laminated via an adhesive (urethane resin system) instead of the aluminum vapor deposition layer. And evaluated. The results are shown in Table 1.

(Example 10)
Example 1 except that a printed image was formed by gravure printing on the aluminum vapor-deposited layer of the long transparent biaxially stretched PET film on which the aluminum-deposited layer was formed, and an adhesive layer was formed on the PET film surface. In the same manner as above, a mirror label and a metal can with a mirror label were prepared and evaluated. The results are shown in Table 1.

(Example 11)
Instead of the protective layer in Example 1, an epoxyamino-based composition was solidly applied and dried as a lower protective layer (hereinafter referred to as “lower layer”) so as to have a dry film thickness of 2 μm, and an upper protective layer (hereinafter referred to as “lower layer”) was applied on the upper surface thereof. A mirror label and a mirror label metal can are produced and evaluated in the same manner as in Example 1 except that the polyester isocyanate-based composition (hereinafter referred to as “upper layer”) is solidly coated and dried so as to have a dry film thickness of 2 μm. Was done. The results are shown in Table 1.

(Example 12)
A mirror label and a mirror label metal can were produced and evaluated in the same manner as in Example 11 except that the degree of curing of the upper layer of the protective layer was set to 5 times for EtOH rubbing. The results are shown in Table 1.

(Example 13)
Instead of the lower layer in Example 11, the epoxy isocyanate-based composition was solidly applied and dried so as to have a dry film thickness of 2 μm, and the gravure printing ink used was a gravure printing ink using an acrylic resin as a base resin. , A mirror label and a mirror label metal can were produced and evaluated in the same manner as in Example 11. The results are shown in Table 1.

(Example 14)
A mirror label and a mirror label metal can were produced in the same manner as in Example 13 except that the gravure printing ink used was a blend of a urethane resin and a vinyl chloride-vinyl acetate copolymer resin as a base resin. Evaluation was performed. The results are shown in Table 1.

(Example 15)
A mirror label and a mirror label metal can were produced and evaluated in the same manner as in Example 14 except that the degree of curing of the upper layer of the protective layer was set to 5 times for EtOH rubbing. The results are shown in Table 1.

(Example 16)
A mirror label and a mirror label metal can were produced and evaluated in the same manner as in Example 11 except that the gravure printing ink using an acrylic resin as a base resin was used as the gravure printing ink. The results are shown in Table 1.

(Comparative Example 1)
A printing film having a gravure printed image formed on one side of a biaxially stretched PET film having a thickness of 12 μm was produced. Further, an aluminum vapor deposition layer (500 Å) was formed on one side of the same biaxially stretched PET film to prepare a vapor deposition film.
A transparent adhesive made of polyester polyurethane resin was laminated on the printing ink surface side of the printing film with the PET film side of the vapor-deposited film, and heat treatment was performed at 60 ° C. for 3 days to prepare a laminated film.
A mirror surface label was produced by applying an adhesive to the vapor-filmed layer side of the prepared laminated film in the same manner as in Example 1 to form an adhesive layer.
In the same manner as in Example 1, it was attached to a metal can to form a finishing varnish layer to prepare a mirror-labeled metal can, and the evaluation was performed. The results are shown in Table 1.

(Comparative Example 2)
A mirror label and a mirror label metal can were produced and evaluated in the same manner as in Example 1 except that the protective layer was not formed. The results are shown in Table 1.

(Comparative Example 3)
A mirror label and a mirror label metal can were produced and evaluated in the same manner as in Example 1 except that the finishing varnish layer was not formed. The results are shown in Table 1.

The mirror surface label of the present invention has a beautiful mirror surface gloss, and when attached to a metal can, peeling of the overlap portion, generation of blister, or generation of wrinkles of the neck portion is effectively prevented, and the appearance characteristics are excellent. Therefore, it can be suitably used for metal cans used for food and drink and cosmetics. Further, since the protective layer has a two-layer structure of a lower protective layer and an upper protective layer made of a specific composition, and printing ink using an acrylic resin as a base resin is used, the retort resistance is also improved. It can also be suitably used for a container filled with contents that require sterilization treatment.

1 mirror label, 10 resin film, 11 gravure print image, 12 protective layer, 12a lower protective layer, 12b upper protective layer, 13 metal layer, 14 adhesive layer, 20 metal can, 21 finish varnish layer, 30 mirror label metal can ..

Claims (12)

Metal layer formation with a metal layer formed on one surface of the resin film A gravure printed image is formed on one surface of the resin film, and a semi-cured protective layer is formed so as to cover the gravure printed image. At the same time, an adhesive layer is formed on the other surface on which the gravure printed image of the metal layer-forming resin film is not formed .
A mirror label characterized in that the protective layer is made of any one of a urethane isocyanate-based composition, a polycarbonate isocyanate-based composition, or a mixture thereof. Metal layer formation with a metal layer formed on one surface of the resin film A gravure printed image is formed on one surface of the resin film, and a semi-cured protective layer is formed so as to cover the gravure printed image. At the same time, an adhesive layer is formed on the other surface on which the gravure-printed image of the metal layer-forming resin film is not formed, and the protective layer is a lower protective layer located on the gravure-printed image side and the lower protective layer. It is a two-layered protective layer composed of an upper protective layer formed on the layer, and the upper protective layer is composed of any one of a polyester isocyanate-based composition, a urethane isocyanate-based composition, and a polycarbonate isocyanate-based composition. A mirror surface label , wherein the lower protective layer is made of either an epoxy isocyanate-based composition or an epoxy amino-based resin composition. The mirror surface according to claim 1 or 2, wherein the resin film is a transparent resin film, the gravure printed image is formed on the resin film side of the metal layer forming resin film, and the adhesive layer is formed on the metal layer side. label. The protective layer on at least one of the edges extending in the can height direction of the mirror label is 10 to 90% of the thickness of the protective layer in the other portion at a width of 0.5 to 10 mm from the edge. The mirror surface label according to any one of claims 1 to 3. The mirror surface label according to any one of claims 2 to 4, wherein the upper protective layer is made of a polyester isocyanate-based composition. The mirror surface label according to any one of claims 2 to 5, wherein the lower protective layer is made of an epoxy isocyanate-based composition. The mirror surface label according to any one of claims 1 to 6 , wherein the base resin of the ink used for the gravure printing is an acrylic resin. A mirror label metal can having the mirror label according to any one of claims 1 to 7, wherein a finishing varnish layer is formed on the mirror label. After the mirror surface label according to any one of claims 1 to 7 is attached to the body of the metal can, a finish varnish is applied on at least the mirror surface label and cured to form a finish varnish layer. A method for manufacturing a mirror-labeled metal can, which is characterized by being formed. A step of forming a gravure print image by gravure printing on one of the resin films on which a metal layer is formed.
A step of forming a semi-cured protective layer so as to cover the gravure printed image.
A step of applying an adhesive to the other surface on which the gravure printed image of the resin film on which the metal layer is formed is not formed to form an adhesive layer.
Only including,
The method for producing a mirror label according to claim 1 , wherein the protective layer is made of any one of a urethane isocyanate-based composition, a polycarbonate isocyanate-based composition, or a mixture thereof. A step of forming a gravure print image by gravure printing on one of the resin films on which a metal layer is formed.
A step of forming a semi-cured protective layer so as to cover the gravure printed image.
A step of applying an adhesive to the other surface on which the gravure printed image of the resin film on which the metal layer is formed is not formed to form an adhesive layer.
Including
The protective layer is a two-layered protective layer composed of a lower protective layer located on the gravure print image side and an upper protective layer formed on the lower protective layer, and the upper protective layer is , Polyester isocyanate-based composition, Urethane isocyanate-based composition, Polycarbonate isocyanate-based composition, and the lower protective layer is composed of any of epoxy isocyanate-based composition and epoxy amino-based resin composition. The method for manufacturing a mirror surface label according to claim 2, wherein the mirror surface label is manufactured. In the step of forming the protective layer, the protective layer at at least one of the edges extending in the can height direction of the mirror surface label is formed, and the thickness of the protective layer at the other portion is 0.5 to 10 mm from the edge. The method for manufacturing a mirror surface label according to claim 10 or 11 , wherein the thickness is 10 to 90% of that of the above.

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