JP2002268556A - Label for metal can and metal can with the label for metal can applied thereon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a label for a metal can which can give superior decoration of the appearance, which can be firmly fixed to the outer surface of the cylinder of a metal can, and which does not produce voids or wrinkles even when the metal can is subjected to severe drawing. SOLUTION: The label for a metal can has a heat-resistant transparent label base material, an adhesive layer consisting of a thermosetting resin and a printed layer formed between the transparent label base material and the adhesive layer, and the label is to be adhered by heating to a metal can. The 180 deg. peeling strength between the transparent base material and the printed layer (under the conditions of 200 mm/minute peeling speed and 15 mm width) is >=4.9 N. An anchor coat layer may be formed between the transparent label base material and the printed layer. Or the printed layer side of the transparent label base material may be treated by N2 purge corona discharge.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal can label which is heated and adhered to a metal can, a metal can provided with the metal can label, and in particular, a void can be formed even if the metal can is provided with a label. The present invention relates to a metal can label that is less likely to cause wrinkles and wrinkles, and a metal can equipped with the metal can label.

[0002]

2. Description of the Related Art Metal cans such as beverage cans for filling beverages such as soft drinks and beer and spray cans for filling gas include three-piece cans composed of a can body, a can bottom and a can lid.
There is a two-piece can composed of a can body in which a can bottom and a can body are integrally formed and a can lid. In recent years, a can body having a plurality of steps formed by performing neck-in processing on a neck portion of a can main body has been increasingly used.

[0003] In such metal cans such as two-piece cans and three-piece cans, the product name, manufacturer name, design and other external decorations are applied by directly printing on the outer peripheral surface of the body of the can body. It is generally done. However, the outer peripheral surface of the body of a metal can (2-piece can) serving as a printing surface is usually
Since it is curved in a cylindrical shape, printability is poor as compared with general film printing, and it is difficult to obtain a beautiful finished state. In particular, there are many problems when performing multi-color printing such as photographic printing, which requires a precise process, and there is a limit even if an attempt is made to provide excellent external decoration on a metal can by printing directly on the outer surface of the body. Was.

For this reason, it has been tried to improve the decorativeness by attaching a shrink label to the body of a metal can.
In the neck-in processing portion and the like, there is a problem that shrinkage of the shrink label becomes uneven, and the upper end and lower end of the shrink label are distorted or torn, and the shrink label is peeled off from the metal can. Also, since the shrink label is not adhered to the body surface of the metal can, if the shrink label reaches the tightened part,
There is an inconvenience that the tightening strength is weakened due to the presence of the non-adhered shrink label.

Therefore, as shown in FIG. 7, a printing layer 30 and an adhesive layer 40 made of a thermosetting resin are sequentially formed on a transparent label base material 20 as a metal can label capable of providing excellent appearance decoration. Laminated adhesive labels 10 are being considered. FIG. 8 is a schematic view showing the can main body 50 in a state where such an adhesive label 10 is attached to the can body of a metal can and then subjected to neck-in processing. According to the adhesive label 10, since it can be securely fixed to the surface of the can body of the metal can by heating and bonding, the strength of the tightening does not decrease even when reaching the tightening portion. However, when a severe drawing process (neck-in process) is applied to the neck portion of the can body as described above, the void 60 and the wrinkle 70 are formed in the neck-in processing portion 50c as shown in FIG.
And the problem that appearance is impaired arises.

[0006]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide not only an excellent appearance decoration, but also a reliable fixing to the outer surface of the body of a metal can, and a severe drawing process to the metal can. It is an object of the present invention to provide a metal can label which is less likely to generate voids and wrinkles even if it is used, and a metal can to which such a metal can label is attached.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies in order to achieve the above object, and as a result, voids and wrinkles (wrinkles) generated by neck-in processing have been produced between the transparent label substrate and the printing layer. Has been found as a starting point, and by adjusting the 180 ° peel strength between the transparent label substrate and the printing layer to a specific value or more, it has been found that the generation of the voids and wrinkles can be suppressed or prevented. The present invention has been completed.

That is, the present invention comprises a transparent label substrate having heat resistance, an adhesive layer made of a thermosetting resin, and a printing layer provided between the transparent label substrate and the adhesive layer. A metal can label heated and adhered to a metal can, wherein the 180 ° peel strength (peeling speed: 200 mm / min, width: 15 mm) between the transparent label substrate and the printing layer is 4.9 N or more. Provide labels for cans.

In the present invention, an anchor coat layer may be provided between the transparent label substrate and the printing layer. This anchor coat layer is preferably formed from a thermosetting resin or a medium.

In the present invention, the surface of the transparent label substrate on the printing layer side may be subjected to an N ₂ purge corona discharge treatment.

The present invention also includes a metal can to which the metal can label is attached.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same members and portions are denoted by the same reference numerals.

FIG. 1 is a schematic sectional view showing an example of the metal can label of the present invention. The metal can label 1 is an exterior label that is heated and adhered to the body (can body) of a can body constituting a metal can such as a beverage can such as canned coffee or canned beer or a spray can. A transparent label substrate formed of a heat-resistant synthetic resin film that hardly shrinks at the heating temperature at the time of heating and bonding (substantially does not shrink in appearance due to adhesion to the can body) (hereinafter, “label substrate” 2), an adhesive layer 5, and a print layer 4 provided between the label substrate 2 and the adhesive layer 5. The label substrate 2 and the print layer 4 An anchor coat layer 3 is provided between them.

In the metal can label 1 shown in FIG. 1, a 180 ° peel strength between the label base material 2 and the printing layer 4 (hereinafter, referred to as “the peel strength”).
"Peeling strength" may be referred to as a peeling speed: 20
4.9 under the condition of 0 mm / min, width: 15 mm
N or more (500 gf or more), preferably 5.88 N or more (600 gf or more), more preferably 6.86 N or more (700 gf or more).

In the present invention, the peel strength between the label substrate 2 and the printed layer 4 (peel speed: 200 mm / min, width: 15 m)
m) is 4.9 N or more, and the upper limit thereof is not particularly limited, and the higher the value, the better. For example, label substrate 2
(Peeling speed: 200 mm / mi)
n, width: 15 mm) is 14.7 N (1500 N).
gf), and 9.8 N (1000 g)
f). If the peel strength between the label substrate 2 and the printing layer 4 is greater than the breaking strength of the label substrate 2 or the printing layer 4, the label substrate may be removed before the label substrate 2 and the printing layer 4 are separated. The material 2 or the printed layer 4 may be broken. Therefore, the upper limit value of the peel strength between the label base material 2 and the print layer 4 may not be measured in some cases. It is also possible to define the breaking strength.

As described above, in the present invention, the peel strength between the label substrate 2 and the printing layer 4 is high, and the label substrate 2
And the printing layer 4 have high adhesion. Therefore, even when severe drawing is performed on the metal can to which the metal can label 1 of the present invention is attached, the generation of voids and wrinkles in the metal can label 1 is suppressed or prevented.

On the other hand, in a conventional metal can label in which a printing layer is directly laminated on a label substrate, the peel strength between the label substrate and the printing layer (peeling speed: 200 mm / min,
(180 ° peel strength under the condition of width: 15 mm) is usually about 1.96 to 2.94 N (200 to 300 gf). Therefore, the adhesion between the label substrate and the printing layer is low, and when severe drawing is applied to the metal can, voids and wrinkles are generated.

As described above, in the present invention, the adhesion between the label substrate and the printing layer is improved, that is, the peel strength between these layers (peeling speed: 200 mm / mi).
n, width: 15 mm) to 4.9 N or more,
The generation of voids and wrinkles in a metal can label subjected to neck-in processing is suppressed or prevented.

(Label Substrate) As the label substrate 2, a transparent synthetic resin film having heat resistance enough to withstand the heat when it is adhered to the body of the can body by heating, for example, polyethylene terephthalate, polybutylene terephthalate, A polyester film such as polyethylene naphthalate or a film obtained by laminating a polyester resin can be used. The film may be a non-stretched film, a uniaxially or biaxially stretched film, but a stretched film, particularly a biaxially stretched film is often used. The label substrate 2 is preferably formed of a biaxially stretched polyester resin film having particularly excellent dimensional stability. The thickness of the label substrate 2 can be appropriately selected within a range that does not impair the strength and heat resistance of the substrate, the sticking workability and the appearance when the label is formed, but is generally about 5 to 50 μm, preferably 9 to
It is about 25 μm.

(Anchor coat layer) Anchor coat layer 3
Can be formed by applying an anchor coat agent to the surface of the label substrate 2. The anchor coating agent is not particularly limited, and enhances the adhesion between the label substrate 2 and the printing layer 4 so that the peel strength between them is 4.9 N.
(500 gf) or more can be used. As the anchor coating agent, for example, a resin composition containing a curable resin such as a non-curable resin, a thermosetting resin, or an ultraviolet-curable resin, or a transparent and non-colored ink (medium) can be used. As the anchor coating agent, a thermosetting resin or a medium is preferable. The anchor coating agents can be used alone or in combination of two or more. Note that an adhesive (for example, a thermosetting adhesive) can be used as the anchor coating agent.

As the thermosetting resin, for example, a thermosetting isocyanate resin, a thermosetting epoxy resin,
A resin such as a thermosetting polyester resin or a resin composition containing a mixture thereof can be suitably used.

When the anchor coating agent is composed of, for example, a thermosetting resin, the anchor coating layer 3 is formed by coating the thermosetting resin with a conventional coating or printing means such as a gravure coater or a reverse coater. It can be formed by coating or printing on the label base material 2 and curing by heat.

When the anchor coat layer 3 is made of an ultraviolet curable resin, an oligomer (photopolymerizable prepolymer), a photopolymerization initiator and, if necessary, a monomer (photopolymerizable diluent) are used. An ultraviolet curable composition containing a sensitizer, a non-reactive resin, a filler, and other additives is applied to the label substrate 2 using a conventional coating or printing means such as a gravure coater or a reverse coater. After being applied or printed on the substrate, dried, and then cured by irradiating ultraviolet rays, the anchor coat layer 3 can be formed.

When the anchor coat layer 3 is made of a thermosetting resin or an ultraviolet curable resin, when the metal can label 1 is adhered to a metal can by heating, or during retort treatment (heating hot water treatment) in a coffee can or the like. In this case, the softening of the anchor coat layer 3 can be prevented by heat.

In the anchor coating agent, the medium (transparent non-colored ink) is not particularly limited, and the adhesion between the label base material 2 and the printing layer 4 is increased to increase the peel strength between them. What is necessary is just to be able to adjust to 9N (500 gf) or more. The medium is a transparent ink containing a large amount of resin components (binder components) and containing a minimum of additives contained in ordinary inks. As the medium, for example, a medium obtained by removing a coloring agent (pigment) from ordinary ink can be used. Therefore, since the medium is an ink, the adhesion between the anchor coat layer 3 and the printing layer 4 is good, and the medium contains a large amount of resin components, so that the adhesion between the anchor coat layer 3 and the label substrate 2 is excellent. ing. In particular, when the resin in the medium and the resin of the print layer 4 are the same type of resin, the adhesion between the anchor coat layer 3 and the print layer 4 is further enhanced. Therefore, the adhesiveness between the label substrate 2 and the printing layer 4 can be increased.

The thickness of the anchor coat layer 3 can be appropriately set within a range that does not impair the adhesion to the label base material 2 or the print layer 4, and is generally about 0.3 to 3 μm (preferably 0.5 to 2 μm). Degree). That is, the anchor coat layer 3 is a thin film as compared with the label base material 2 and the like.

The printing layer 4 is formed on the surface of the anchor coat layer 3 by using a known printing technique such as gravure printing, flexographic printing, offset printing or the like using an ink containing a transparent or opaque coloring pigment. In particular, gravure printing is performed using a heat-resistant ink (further, a two-component curable ink) such as a one-component or two-component curable ink containing a urethane-based resin component. desirable. The thickness of the printing layer 4 is, for example, about 1 to 8 μm, and preferably about 2 to 5 μm.

The adhesive layer 5 is made of a thermosetting resin. Examples of the thermosetting resin include, for example, an epoxy resin, a phenol resin, an aminoplast resin, a thermosetting polyester resin, a urethane resin, or a simple substance or a mixture (for example, an epoxy phenol resin or a polyester / isocyanate resin). No. Among these, epoxy resins and thermosetting polyester resins are preferable in terms of heat resistance, adhesion, workability, and the like, and thermosetting polyester resins are particularly preferable in terms of sticking workability. The adhesive layer 5 is formed by coating a solution containing such a thermosetting resin composition as a main component with a dry coating of, for example, 0.5 to 0.5 μm using a conventional coating technique such as gravure coating.
It can be formed by coating on the print layer 4 to have a thickness of 20 μm.

As described above, in FIG. 1, by providing the anchor coat layer 3 between the label substrate 2 and the printing layer 4, the peel strength between the label substrate 2 and the printing layer 4 is increased, Improve the quality. In the present invention, the adhesion between the label base material 2 and the print layer 4 is increased to increase the peel strength to 4.9 N (50 N).
0 gf) or more, the method is not particularly limited. For example, a method of performing a nitrogen-substituted corona discharge treatment (N ₂ purge corona discharge treatment) on the surface of the label substrate 2 on the print layer 4 side can be adopted.

(N ₂ Purge Corona Discharge Treatment) FIG. 2 is a schematic sectional view showing another example of the metal can label of the present invention. The metal can label 11 also has a body (can body) of a can body constituting a metal can, such as a beverage can or a spray can, such as canned coffee or canned beer, like the metal can label 1 according to FIG. This is an exterior label that is heated and adhered to the surface. The metal can label 11 according to FIG. 2 is made of a heat-resistant synthetic resin film that hardly shrinks at the heating temperature at the time of heating and bonding to the can main body (substantially does not shrink in appearance due to adhesion to the can main body). A transparent label base material (hereinafter, sometimes referred to as a “corona-treated label base material”) 21 having an inner surface subjected to an N ₂ purge corona discharge treatment, and an adhesive layer 5
And a printing layer 4 provided between the corona-treated label substrate 21 and the adhesive layer 5.

In the example of FIG. 2, the outermost transparent label substrate 2
1 has N ₂ on its inner surface (that is, the surface on the printing layer side).
It is the same as the label base material 2 according to FIG. 1 except that the purge corona discharge treatment is performed. The adhesive layer 5 and the print layer 4 are respectively the adhesive layer 5 and the print layer 4 shown in FIG.
The same as for the print layer 4.

As described above, the inside of the transparent label substrate 21 is
N (the print layer side) _TwoPurge corona discharge
By performing the treatment, a corona-treated label base material 21,
Adhesion with the printing layer 4 can be increased. That
In the metal can label 11 shown in FIG.
Peel strength between the physical label substrate 21 and the printed layer 4 (peeling speed
Degree: 200 mm / min, width: 15 mm
180 ° peel strength) can be adjusted to 4.9N or more.
Wear.

As described above, in the present invention, the N ₂ purge corona discharge treatment is performed by providing the anchor coat layer between the transparent label base material and the printing layer, or on the surface of the transparent label base material on the printing layer side. By applying, the peel strength between the label substrate and the printing layer (peeling speed: 200 mm / min, width:
180 ° peel strength under the condition of 15 mm) is 4.9 N
The above can be adjusted. Therefore, the adhesion between the label substrate and the printing layer is excellent, and even if the metal can label having such a configuration is attached to the metal can and severe drawing is performed on the metal can, voids and wrinkles are completely eliminated. Or almost never occurs.

In the present invention, a layer such as a metal deposition layer may be provided. The metal deposition layer is, for example, the printing layer 4
And the adhesive layer 5. An anchor coat layer may be provided between these layers in order to enhance the adhesion between the printing layer and the metal deposition layer. In addition,
Aluminum, chromium, silver,
Metals such as copper and tin can be employed.

The metal can to which the metal can label 1 having such a configuration is attached can be manufactured as follows. In addition,
3 is a partially cutaway sectional view showing an example of the can body as it is, FIG. 4 is a side view showing the can body with the metal can label shown in FIG. 1 attached, and FIG. FIG. 6 is a side view showing a metal can in which a can lid is attached to the can main body of FIG. 5.
In these figures (FIGS. 3 to 6), reference numeral 7 denotes an overcoat layer.

First, as shown in FIG. 3, a can body 6 in which a can bottom 6a and a cylindrical can body 6b are integrally formed by deep drawing and ironing a surface-treated aluminum plate.
Is heated to, for example, about 80 to 180 ° C., and the metal can label 1 is placed on the outer peripheral surface of the can body portion 6b of the can body 6 in a state where the adhesive layer 5 is located inside as shown in FIG. Winding, pressing and bonding, further applying an overcoat agent, performing a curing treatment, and if necessary, curing the adhesive layer 5 by heating, so that the outer peripheral surface of the can body 6b
The metal can label 1 and the overcoat layer 7 can be sequentially laminated and attached to the can body 6.

At this time, the upper end of the metal can label 1 may be aligned with the upper end of the can body 6b. Since the tightening may be hindered, the upper end of the metal can label 1 is 0.1 to 3 mm above the upper end of the can body 6b.
It is preferable that the bonding is performed so as to be located below about 0 mm (preferably about 0.2 to 2.0 mm). Also, the lower end of the metal can label 1 may be made to coincide with the lower end of the can body 6b similarly to the upper end, but the lower end of the metal can label 1 is 0.1 to 3 mm lower than the lower end of the can body 6b. It is preferable that the adhesive is adhered so as to be positioned above about 0.0 mm (preferably about 0.2 to 0.8 mm), but slightly toward the bottom of the can (for example, about 0.0 mm).
(About 1 to 3 mm) may be extended. Further, at this time, a double winding portion (overlapping portion) X in which the winding end portion is overlapped within a range of several millimeters is formed at the winding start end portion of the metal can label 1, and the body of the can body 6 is securely formed. The entire peripheral surface of the portion 6b is covered with the metal can label 1.

The overcoat layer 7 may be provided as needed, and is not necessarily provided. The overcoat layer 7 can be formed by applying an overcoat agent so as to cover the entire surface of the metal can label 1 and performing a curing treatment. In this application, the can body 6b
Has an open end 6x (can body 6) at its upper end side or lower end side.
b) has a portion that is not covered by the metal can label 1), the overcoat is applied to the can body 6
It is preferable that the coating is applied to the open end of b so as to cover the entire surface of the metal can label 1. In this way, by covering the open end of the can body 6b with the overcoat layer together with the entire surface of the metal can label 1, the metal can label 1 can be made hard to peel off. When the overcoat layer 7 is provided on the open end 6x, the open end 6
It is not always necessary to provide it on the entire surface of x. That is, the overcoat layer 7 can be provided at least at a portion near the upper end or the lower end of the metal can label 1 at the open end 6x. In the present invention, the overcoat layer 7 is preferably provided on the entire open end 6x. Also,
The overcoat layer 7 is preferably provided also at the tip of the can flange portion.

The overcoat agent is not particularly limited, and a known overcoat agent can be used. Specifically, examples of the overcoat agent include a thermosetting transparent resin-based varnish (varnish), an ultraviolet curable resin composition, and an electron beam curable resin composition.
As the overcoat agent, a thermosetting transparent resin varnish is particularly suitable. As the thermosetting resin composition used in such a thermosetting transparent resin varnish,
For example, an acrylic thermosetting resin, an amino thermosetting resin, an epoxy thermosetting resin, an ester thermosetting resin, and the like can be given. In the present invention, a thermosetting resin composition containing an acrylic resin as a main component or an ultraviolet curable resin composition containing an ultraviolet curable resin as a main component can be suitably used. Such an overcoat agent (such as a thermosetting transparent resin-based varnish) may be water-based or a solvent-based (organic solvent-based).

As the curing treatment of the applied overcoat agent, for example, when the overcoat agent is varnish, baking and curing by heating with hot air at a temperature of 100 to 220 ° C. or more for several seconds to several tens minutes. Processing methods can be employed. In this baking hardening process, the overcoat agent can be hardened to form the overcoat layer 7 and the adhesive layer 5 can be completely hardened. When the overcoat agent is an ultraviolet curable resin or an electron beam curable resin, the curing treatment can be performed by irradiation with ultraviolet light or an electron beam. In this case,
100-220 ° C or more with hot air at a temperature of several seconds or more
By heating for several tens of minutes, the adhesive layer 5 can be completely cured.

Next, as shown in FIG. 5, the metal can label 1 is heated and adhered to the can body 6b, and a neck is formed on the top of the can body 6b after the overcoat layer 7 is formed by curing. The neck-in processing section 6c having a diameter reduced to one or more steps is formed by performing an in-process.

The neck body 6 thus subjected to neck-in processing is shipped to a factory for manufacturing contents such as soft drinks, where the contents are filled into the can body 6, and then as shown in FIG. Then, the separately prepared can lid 8 is firmly integrated with the end of the neck-in processing section 6c by a winding process,
A closed metal can 9 is formed. The can lid 8 is usually processed (not shown) for forming a drinking port such as a pull tab.

A metal can provided with the metal can label 11 can be manufactured in the same manner.

The metal can 9 formed as described above is
The neck-in process is performed after the metal can label 1 (or 11) provided with the printing layer 4 and, if necessary, an overcoat layer (such as a burnish layer) are attached to the outer peripheral surface of the can body 6. Therefore, it is possible to easily provide a more precise and beautiful appearance decoration than a conventional metal can that directly prints on the surface of the curved can body 6.

Since the metal can label 1 (or 11) is completely adhered to the surface of the can body 6, the metal can label 1 is fastened to the winding portion 6 so that the background of the can body 6 is not visible.
d, the metal can 9 having excellent appearance and decoration and good sealing performance without lowering the tightening strength.
Is obtained.

In particular, since the adhesion between the label substrate 2 (or 21) of the label 1 (or 11) and the printing layer 4 is excellent, the can body 6 to which the label 1 (or 11) is attached is provided. Even when severe drawing is performed or when the contents of the can body 6 are filled and retorted, the label 1 (or 11) hardly generates voids and wrinkles.

In particular, in the present invention, the label 1 for a metal can is
When the entire surface is covered with the overcoat layer 7, excellent slipperiness can be obtained and scratches can be prevented. In particular, when the overcoat layer 7 covers the open end 6x of the can body 6b of the metal can beyond the metal can label 1, the end of the metal can label 1 is exposed. Not
Since it is completely covered by the overcoat layer 7,
It is hard to come off.

In the above embodiment, a two-piece aluminum can formed from a surface-treated metal plate has been described. However, it is needless to say that the present invention can be applied to cans of various materials in addition to a normal DI can or a steel can. Nor.
That is, in the present invention, the material of the metal can is not particularly limited. The shape or structure of the metal can is not particularly limited, and may be a two-piece can, a monoblock can, or a three-piece can.
It may be a can of three or more pieces such as a piece can.

It is preferable to use a metal can formed of a surface-treated metal plate (eg, a surface-treated aluminum plate). When the metal can is surface-treated, the adhesion with the metal can label can be increased,
The metal can label can be attached to the periphery of the can body of the metal can with higher adhesion. As such a surface treatment method, for example, an acidic treatment liquid (pH: about 1.0 to 4.0) containing zirconium, titanium or a compound containing any of these, and a phosphate and a fluoride is used. In addition to the method of forming a chemical conversion coating layer (coating amount: 3 to 15 mg / m ² ) containing zirconium and / or titanium phosphate as a main component (zirconium surface treatment method, titanium surface treatment method, etc.), chromium An acid chromate conversion treatment method or a phosphoric acid chromate conversion treatment method may, for example, be mentioned. In the present invention, as the surface treatment method, the method of forming a chemical conversion coating layer containing the zirconium phosphate as a main component (zirconium surface treatment method) is preferable from the viewpoint of adhesion to a metal can label (film). .

The present invention is particularly suitable for beverage cans and spray cans.

[0051]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention.

Example 1 One side of a biaxially stretched polyethylene terephthalate (PET) film having a thickness of 12 μm was
As an anchor coating agent, a medium mainly composed of a two-component curable urethane-based resin is applied or printed with a thickness of 1 μm by a gravure coater, and subsequently, 3 to 4 μm is coated on the anchor coating layer by the anchor coating agent. Gravure printing was performed with a thickness, characters and designs were formed, and a printing layer was formed. Further, a polyester-based thermosetting adhesive was applied at a thickness of 1.8 g / m ² on the printed layer to form an adhesive layer, thereby producing a metal can label.

A can body of an aluminum metal can having a zirconium surface treatment, in which a can bottom and a can body are integrally formed, is heated to a temperature of 130 ° C. or more, and the body is obtained by the metal can obtained above. The label was stuck to the adhesive layer surface of the label for application. After the label is applied, the thermosetting resin composition containing an acrylic resin as a main component as an overcoat agent is not covered with the entire surface of the metal can label and the label in the vertical direction of the can body of the aluminum metal can. The coating was applied to the entire open end and the tip of the can flange. After applying the overcoat agent, the can temperature is 180 ° C
After heating the can to hold it for 30 seconds, and then coating the inner surface of the can with an aqueous epoxy acrylic resin paint, heating the can to keep it at 200 ° C for 1 minute to cure the overcoat agent and bond it. The layer and the anchor coat layer were cured to prepare a metal can (aluminum metal can) in which the metal can label and the overcoat layer were laminated and mounted on the can body of the metal can in this order.

In the aluminum metal can, the 180 ° peel strength between the label base material and the printed layer was measured at a peeling speed of 20.
It was 8.72 N (890 gf) when measured under the conditions of 0 mm / min and width: 15 mm. In the present invention, the 180 ° peel strength (N) of the metal can label was measured after being mounted on a metal can (such as an aluminum metal can) and then cut to a width of 15 mm.

Thereafter, neck-in processing was performed on the upper part of the can body of the aluminum metal can, but no void or wrinkle was generated on the label.

(Example 2) A biaxially stretched polyethylene terephthalate (PET) film having a thickness of 12 μm and having one surface subjected to an N ₂ purge corona discharge treatment, a thickness of 3 to 4 μm was formed on the corona discharge treated surface. Do gravure printing,
Printed layers were formed by forming letters and designs. Further, a polyester-based thermosetting adhesive was applied at a thickness of 1.8 g / m ² on the printed layer to form an adhesive layer, thereby producing a metal can label.

A can body of an aluminum metal can having a zirconium surface treatment, in which a can bottom and a can body are integrally formed, is heated to a temperature of 130 ° C. or more, and the body is obtained by the metal can obtained above. The label was stuck to the adhesive layer surface of the label for application. After the label is applied, the thermosetting resin composition containing an acrylic resin as a main component as an overcoat agent is not covered with the entire surface of the metal can label and the label in the vertical direction of the can body of the aluminum metal can. The coating was applied to the entire open end and the tip of the can flange. After applying the overcoat agent, the can temperature is 180 ° C
After heating the can to hold it for 30 seconds, and then coating the inner surface of the can with an aqueous epoxy acrylic resin paint, heating the can to keep it at 200 ° C for 1 minute to cure the overcoat agent and bond it. Cure the layer,
The metal can label and the overcoat layer were laminated on the can body of the metal can in this order to prepare a mounted metal can (aluminum metal can).

In the aluminum metal can, the 180 ° peel strength between the label base material and the printed layer was measured at a peel speed of 20.
It was 5.98 N (610 gf) when measured under the conditions of 0 mm / min and a width of 15 mm.

Thereafter, neck-in processing was performed on the upper part of the can body of the aluminum metal can, but no void or wrinkle was generated on the label.

Example 3 One side of a biaxially stretched polyethylene terephthalate (PET) film having a thickness of 12 μm was
Using a thermosetting adhesive mainly composed of a polyester resin as an anchor coating agent, gravure printing was performed to a thickness of 1 μm to form an anchor coating layer. Thereafter, gravure printing was performed to a thickness of 3 to 4 μm on the anchor coat layer to form letters and designs, thereby forming a print layer. Further, a polyester-based thermosetting adhesive was applied at a thickness of 1.8 g / m ² on the printed layer to form an adhesive layer, thereby producing a metal can label.

A can body of an aluminum metal can having a zirconium surface treatment, in which a can bottom and a can body are integrally formed, is heated to a temperature of 130 ° C. or more, and the body is heated to a temperature of 130 ° C. or more. The label was stuck to the adhesive layer surface of the label for application. After the label is applied, the thermosetting resin composition containing an acrylic resin as a main component as an overcoat agent is not covered with the entire surface of the metal can label and the label in the vertical direction of the can body of the aluminum metal can. The coating was applied to the entire open end and the tip of the can flange. After applying the overcoat agent, the can temperature is 180 ° C
After heating the can to hold it for 30 seconds, and then coating the inner surface of the can with an aqueous epoxy acrylic resin paint, heating the can to keep it at 200 ° C for 1 minute to cure the overcoat agent and bond it. The layer and the anchor coat layer were cured to prepare a metal can (aluminum metal can) in which the metal can label and the overcoat layer were laminated and mounted on the can body of the metal can in this order.

In the metal can label, the 180 ° peel strength between the label substrate and the printed layer was measured by measuring the peeling speed: 200 mm.
/ Min, width: 15 mm.
It was 8.33N (850gf).

Thereafter, neck-in processing was performed on the upper part of the main body of the aluminum metal can, but no void or wrinkle was generated on the label.

Example 4 A steel metal can with a zirconium surface treatment was used instead of an aluminum metal can with a zirconium surface treatment.
In the same manner as in Example 1, a metal can (steel metal can) to which a metal can label was attached was produced. In the steel metal can, the 180 ° peel strength between the label substrate and the printed layer was measured under the conditions of a peeling speed of 200 mm / min and a width of 15 mm, and it was 8.82 N (900 gf).

Thereafter, neck-in processing was performed on the upper part of the can body of the steel metal can, but no void or wrinkle was generated on the label.

Example 5 A steel metal can having a zirconium surface treatment was used instead of an aluminum metal can having a zirconium surface treatment.
In the same manner as in Example 2, a metal can (steel metal can) to which a metal can label was attached was produced. In the steel metal can, the 180 ° peel strength between the label substrate and the printed layer was measured under the conditions of a peeling speed of 200 mm / min and a width of 15 mm, and was 5.88 N (600 gf).

Thereafter, neck-in processing was performed on the upper part of the can body of the steel metal can, but no void or wrinkle was generated on the label.

Example 6 A steel metal can having a zirconium surface treatment was used instead of an aluminum metal can having a zirconium surface treatment.
In the same manner as in Example 3, a metal can (steel metal can) to which a metal can label was attached was produced. In the steel metal can, the 180 ° peel strength between the label substrate and the printed layer was measured under the conditions of a peeling speed of 200 mm / min and a width of 15 mm, and was found to be 8.33 N (850 gf).

Thereafter, neck-in processing was performed on the upper part of the main body of the steel metal can, but no void or wrinkle was generated on the label.

Comparative Example 1 One side of a biaxially stretched polyethylene terephthalate (PET) film having a thickness of 12 μm was
Gravure printing was performed to a thickness of 3 to 4 μm to form characters and designs, and a printing layer was formed. Further, on the printed layer, a polyester-based thermosetting adhesive was applied at 1.8 g /
An adhesive layer was formed by coating with a film thickness of m ² to produce a metal can label.

A can body of an aluminum metal can having a zirconium surface treatment, in which a can bottom and a can body are integrally formed, is heated to a temperature of 130 ° C. or more, and the body is obtained by the metal can obtained above. The label was stuck to the adhesive layer surface of the label for application. After the label is applied, the thermosetting resin composition containing an acrylic resin as a main component as an overcoat agent is not covered with the entire surface of the metal can label and the label in the vertical direction of the can body of the aluminum metal can. The coating was applied to the entire open end and the tip of the can flange. After applying the overcoat agent, the can temperature is 180 ° C
After heating the can to hold it for 30 seconds, and then coating the inner surface of the can with an aqueous epoxy acrylic resin paint, heating the can to keep it at 200 ° C for 1 minute to cure the overcoat agent and bond it. Cure the layer,
The metal can label and the overcoat layer were laminated on the can body of the metal can in this order to prepare a mounted metal can (aluminum metal can).

In the aluminum metal can, the 180 ° peel strength between the label base material and the printed layer was measured at a peeling speed of 20.
It was 3.14 N (320 gf) when measured under the conditions of 0 mm / min and width: 15 mm.

Then, when neck-in processing was performed on the upper part of the can body of the aluminum metal can, many voids and wrinkles as shown in FIG. 8 were generated.

Comparative Example 2 A steel metal can having a zirconium surface treatment was used in place of an aluminum metal can having a zirconium surface treatment.
In the same manner as in Comparative Example 1, a metal can (steel metal can) to which a metal can label was attached was produced. In the steel metal can, the 180 ° peel strength between the label substrate and the printed layer was measured under the conditions of a peel speed of 200 mm / min and a width of 15 mm, and it was 2.74 N (280 gf).

Thereafter, neck-in processing was performed on the upper part of the can body of the steel metal can. As in Comparative Example 1, a large number of voids and wrinkles as shown in FIG.
Had occurred.

According to the present invention, since the 180 ° peel strength between the transparent label substrate and the printing layer is a specific value or more, the transparent label substrate and the printing layer are firmly adhered to each other. ,
Even if neck-in processing is performed on the metal can after the label is attached, no voids or wrinkles are generated.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a metal can label of the present invention.

FIG. 2 is a sectional view showing another example of the metal can label of the present invention.

FIG. 3 is a partially cutaway sectional view showing the can body as it is.

FIG. 4 is a side view showing the can main body in a state where the metal can label shown in FIG. 1 is mounted.

FIG. 5 is a side view showing the can body in a state where neck-in processing has been further performed.

FIG. 6 is a side view showing a metal can in which a can lid is attached to the can main body of FIG. 6;

FIG. 7 is a cross-sectional view showing a conventional metal can label.

FIG. 8 is a schematic view showing an upper portion of a can main body in a state where a conventional metal can label is attached and neck-in processing is performed.

[Explanation of symbols]

1, 11, 12 metal can label 2 label substrate 21 N ₂ Pajikorona discharge treatment label substrate 3 anchor coat layer 4 printed layer 5 adhesive layer 6 cans which subjected the body 6a can bottom 6b can body 6c neck-in processing unit 6d Winding part 7 Overcoat layer 8 Can lid 9 Metal can 10 Label for conventional metal can 60 Void 70 Wrinkle

Continued on the front page (72) Inventor Masakazu Goto 5-3-1-18 Imazukita, Tsurumi-ku, Osaka City Inside Fuji Seal Co., Ltd. (72) Inventor Kenta Kato 1500 Suganuma, Koyamacho, Sunto-gun, Shizuoka Prefecture Mitsubishi Materials Corporation Aluminum can Inside the development center (72) Inventor Takehito Shirasawa 1500 Suganuma, Koyama-cho, Sunto-gun, Shizuoka Prefecture Mitsubishi Materials Corporation Aluminum can development center F-term (reference) 3E062 AA04 AB02 AC03 DA01 DA02 DA07 JA08 JB04 JC02 JD10

Claims (6)

[Claims] 1. A method for heating a metal can, comprising: a transparent label substrate having heat resistance; an adhesive layer made of a thermosetting resin; and a printing layer provided between the transparent label substrate and the adhesive layer. A metal can label to be adhered, comprising: a 180 ° peel strength (peeling speed: 200) between the transparent label substrate and a printing layer.
mm / min, width: 15 mm) is 4.9 N or more. 2. The metal can label according to claim 1, further comprising an anchor coat layer between the transparent label substrate and the printing layer. 3. The metal can label according to claim 2, wherein the anchor coat layer is formed from a thermosetting resin or a medium. 4. The method according to claim 1, wherein the surface of the transparent label substrate on the printing layer side is N ₂
The metal can label according to claim 1, which has been subjected to a purge corona discharge treatment. 5. The metal can label according to claim 1, wherein the transparent label substrate is formed of a polyester resin film. 6. A metal can to which the metal can label according to claim 1 is attached.