JP2000153576A - Two-piece can body and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a two-piece can body wherein a coating layer of a crystalline polyester film is provided on the outer surface of a can and to produce the same without generating the pollution of working environment caused by the baking of printing. SOLUTION: A polyester film 8 having a printing layer 10 capable of obtaining a proper pattern when a bottomed cylindrical body is molded and a thermosetting adhesive layer 9 is bonded to the surface becoming a can outer surface of a metal panel 2 for a can through the thermosetting adhesive layer 9 and this metal panel is molded into the bottomed cylindrical body. The polyester film 8 having the thermosetting adhesive layer 9 is bonded to the surface becoming a can inner surface of the metal panel 2. The polyester film 8 is a single-layered film comprising crystalline polyester such as PET or the like and the degree of crystallization of at least the range 8a of at least 20% of the whole thickness of the film on the side opposed to the metal panel 2 is 20% or less and the degree of crystallization of the range 8b of at least 5% of the whole thickness of the film from an outer surface is 20% or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-piece can used for food cans, beverage cans and the like, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, as a two-piece can for food and beverage cans, a drawn can made by forming a thin metal plate for a can into a bottomed tubular body by drawing, and a bottomed tubular body by drawing and ironing. Known drawn ironing cans and the like are known.

[0003] Among these, first, the draw can is formed by punching a thin metal plate for a can, such as an aluminum material, a tinned material, a tin-free steel (hereinafter abbreviated as TFS) material, into a disk shape. Draw with a punch and a die to form a bottomed cylindrical body, then trimming and flange processing on the bottomed cylindrical body, forming a neck portion, bead portion, etc. on the body, doming on the bottom And the like.

[0004] The drawn can is a shallow drawn can having a small ratio of the can height to the can diameter, a deep drawn can having a large can height ratio to the can diameter, and a process of extending the body portion and reducing the wall thickness by deep drawing. There is a type such as a body thin-wall deep-drawing can having a larger can height ratio with respect to the can diameter, and the processing becomes more severe as the can height ratio with respect to the can diameter increases. Therefore, in the method for producing a drawn can, on the outer surface side of the can metal plate for the can, an outer surface printing for imparting in advance a cosmetic property for enhancing the willingness to purchase, a product name, a raw material name, and a required display such as a manufacturer is provided. When applied, as the ratio of the can height to the can diameter increases, the drawing on the outer surface is more likely to be damaged by the drawing process, and the aesthetics and required display are more likely to be impaired.

[0005] Next, in the method of manufacturing the drawn and ironed can,
First, a thin metal plate for a can made of the aluminum material or the steel material is punched into a disk shape, formed into a cup shape, and drawn and ironed to form a bottomed cylindrical body. Next, the inner and outer surfaces of the bottomed cylindrical body are degreased and washed with water, a chemical conversion treatment is performed on the surface of the metal material, and the opening end is trimmed. Then, after the trimming, the outer surface of the can is subjected to printing for imparting the aesthetic and required display, the inner surface of the can is painted, and after baking, neck-in processing is performed on the can body and the edge of the can body. Flange processing is performed.

In the method of manufacturing the drawn ironing can described above, since the outer surface printing is performed after the drawing ironing process, there is no possibility that the outer surface printing may damage the aesthetics or required display by the outer surface printing, but the number of steps is large and complicated. Therefore, improvement is desired. Further, in the method for manufacturing the drawn and ironed can, a large amount of lubricating oil is required in the drawn and ironed process, so that degreasing after forming the bottomed cylindrical body and washing with water are indispensable. Requires water. Further, since a large amount of water is required also in the chemical conversion treatment, there is a problem that a large-scale wastewater treatment facility is required.

Further, in the conventional method for manufacturing a two-piece can, the outer surface printing is performed, whether it is a drawn can or a squeezed ironing can. There is a problem that the working environment is polluted by the emitted carbon dioxide and the volatilization of the organic solvent.

In recent years, a polyester film has been laminated on the inner and outer surfaces of a metal plate for a can, and the metal plate covered with the polyester film has been subjected to a stretch draw process to form a bottomed cylindrical body. A production method has been proposed in which printing is performed on a polyester film that covers the outer surface side of the can of the body to give the above-described aesthetics and required display.

However, if the printing is performed after the metal plate for a can is formed into a bottomed cylindrical body, a step of heating and drying the printing is required as in the conventional manufacturing method. There is a disadvantage that contamination of the working environment cannot be prevented. Further, the polyester film has insufficient workability and adhesiveness, and cannot be followed by a large deformation at the time of forming the metal plate for the can into the bottomed cylindrical body, and is damaged or the metal film is deformed. There is a disadvantage that it may peel off from the plate.

[0010]

SUMMARY OF THE INVENTION The present invention solves such inconveniences and provides a coating layer made of a crystalline polyester film on at least the outer surface of the can to prevent contamination of the working environment caused by baking the print in an oven. It is an object of the present invention to provide a two-piece can body and a manufacturing method thereof.

[0011]

In order to achieve the above object, a two-piece can according to the present invention has a printing layer and a laminated layer formed on the printing layer, at least on the side of the metal plate for the can which is to be the outer surface of the can. A polyester film having a thermosetting adhesive layer on one surface, and a printed film-coated metal plate formed by bonding through the thermosetting adhesive layer to a bottomed cylindrical body. .

According to the two-piece can body of the present invention, a printed film-coated metal plate is formed by bonding a polyester film, which has been printed on the outer surface of the can in advance, to a metal plate for a can. The plate is formed into a bottomed cylindrical body. Therefore, it is possible to impart aesthetics and required indications to the outer surface of the can without printing on the outer surface of the can of the bottomed cylindrical body or baking the print in an oven.

[0013] Since the polyester film is bonded to the metal material for a can via the thermosetting adhesive layer provided on the printing layer, the printing layer is formed of the polyester film and the adhesive. It is configured to be sandwiched between layers. As a result, the printing layer is protected by the polyester film, and the aesthetics and required display are not impaired.

Further, since the polyester film is bonded to the metal material for a can via the thermosetting adhesive layer, deformation of forming the printing film-coated metal plate into a bottomed cylindrical body is large. After processing, or filling the contents into a two-piece can obtained from the bottomed cylindrical body, 1
Even if a retort treatment exceeding 00 ° C. is performed, excellent adhesion without peeling from the metal plate can be obtained.

[0015] In the two-piece can body of the present invention, a polyester film having a thermosetting adhesive layer on one surface of the metal plate for a can is provided on the inner side of the can. It is preferable that they are adhered through a gap. By doing so, it is possible to form an inner surface protection layer for protecting the metal surface on the inner surface side of the can without applying a coating for coating the metal surface on the inner surface side of the can of the metal plate for the can.

Further, in the two-piece can of the present invention, the polyester film is a single-layer film made of a crystalline polyester resin, and has a thickness of the entire film from the surface facing the metal plate for the can. At least 2
Preferably, the crystallinity in the range of 0% is 20% or less, and the crystallinity in the range of at least 5% of the total thickness of the film from the outer surface is 20% or more. Since the polyester film is a single-layer film, after the printed film-coated metal plate is formed into a bottomed cylindrical body, delamination may occur as in a multilayer structure film in which a plurality of films having different resin compositions are laminated. There is no.

The polyester film has a crystallinity of 20% or less in a range of at least 20% of the thickness of the entire film from the surface facing the metal plate for a can, and is in an amorphous state or a state close thereto. So that
Excellent adhesion can be obtained by easily following large deformation when the printed film-coated metal plate is formed into a bottomed cylindrical body. In addition, the polyester film has a high degree of crystallinity in a range of at least 5% of the total thickness of the film from the outer surface to at least 20%, and thus has high strength. When the film is formed, damage to the film due to contact with a tool can be reduced.

The polyester film has a crystallinity of more than 20% or a crystallinity of not more than 20% in a range of at least 20% of the thickness of the entire film from the surface facing the metal plate for a can. When the portion is less than 20% of the thickness of the entire film from the surface on the side facing the metal plate for a can, the film may undergo large deformation when forming the printed film-coated metal plate into a bottomed cylindrical body. It may peel off without being able to follow. Further, the crystallinity in the range of at least 5% of the thickness of the entire film from the outer surface of the polyester film is less than 20% or the portion where the crystallinity is 20% or more is 5% of the thickness of the entire film from the outer surface. %, The film may be seriously damaged by contact with a tool when the printed film-coated metal plate is formed into a bottomed cylindrical body.

A typical example of the crystalline polyester film is a film substantially composed of a single polyethylene terephthalate resin. The polyethylene terephthalate resin is a resin obtained by polymerization of terephthalic acid and ethylene glycol, and is preferably used because the distribution of the crystallinity as described above can be easily achieved. Other components may be included as long as the above crystallinity is maintained without loss. As the other component, a part of the terephthalic acid may be replaced with another dibasic acid, for example, isophthalic acid or naphthalic acid, or a part of the ethylene glycol may be replaced with another dihydric alcohol. . Further, the other component may be a polyester other than polyethylene terephthalate. Further, it is more preferable that the polyethylene terephthalate resin is a biaxially stretched polyethylene terephthalate resin in that it has strength suitable for printing.

In order to obtain strong adhesion between the film made of the polyester resin and the metal plate for a can, a thermosetting adhesive is suitable as the adhesive. Examples thereof include an epoxy resin containing a phenoxy resin, a polyester resin, a urethane-based resin, and an acrylic resin. A modified epoxy resin such as a modified polyester resin can be used as the epoxy resin, and a modified polyester resin can also be used as the polyester resin. The resin used as the main agent can be used alone or in combination. Preferred examples of the curing agent used by blending with the main agent include any one or more of an acid anhydride, an aminoplast, a phenol resin, and a urethane-based curing agent. As the thermosetting resin composition using the main agent and the curing agent, specifically, for example, a resin composition composed of an epoxy resin and an acid anhydride or a phenol resin or a polyester resin and an aminoplast or urethane-based curing agent And a resin composition comprising:

As described above, the polyester film has a crystallinity of at least 20% or more in a range of at least 5% of the thickness of the entire film from the outer surface. Although damage can be reduced when the film is formed into a shape, the outer surface of the film may be slightly roughened by the forming. Therefore, in the two-piece can body of the present invention, an overcoat layer is provided on the surface of the polyester film adhered to the outer surface of the bottomed tubular body. According to the overcoat layer, since the surface of the polyester film is smoothed, when the bottomed tubular body is transported to a subsequent process in a state of being raised, friction due to contact between the bottomed tubular bodies is caused. And troubles can be avoided.

The two-piece can body of the present invention has a printing layer on at least a side of the metal plate for a can which is to be the outer surface of the can, and a printed layer capable of obtaining an appropriate pattern when a bottomed cylindrical body is formed from the metal plate for a can. Bonding a polyester film provided on one surface with a thermosetting adhesive layer laminated on the printing layer via the thermosetting adhesive layer to form a printed film-coated metal plate; Forming a bottomed tubular body from a printed film-coated metal plate.

According to the manufacturing method of the present invention, since the bottomed tubular body is formed from the printed film-coated metal plate obtained by bonding the polyester film having the printing layer, the outer surface of the can of the bottomed tubular body is formed. It is not necessary to perform printing on the side, and it is possible to prevent contamination of the working environment due to combustion waste gas when the print is baked in an oven, carbon dioxide discharged along with the gas, and volatilization of an organic solvent. Since the polyester film is adhered to the metal material for the can via the thermosetting adhesive layer, the polyester film is separated from the metal plate even when the printed film-coated metal plate is formed into a bottomed cylindrical body. No excellent adhesion is obtained.

Further, since the printing layer is sandwiched between the polyester film and the thermosetting adhesive layer as described above, the printing film-covered metal plate is formed into a bottomed cylindrical body. In this case, the printing layer is protected by the polyester film and does not directly contact the tool. Therefore, according to the manufacturing method of the present invention, it is possible to prevent the cosmetics of the print layer and the required display from being damaged due to the contact between the print layer and the tool.

According to the production method of the present invention, there is no need to apply a coating to the inner surface of the can, and it is possible to prevent contamination of the working environment due to baking the coating in an oven.
It is preferable that a step of bonding a polyester film having a thermosetting adhesive layer on one surface thereof to the inner side of the metal plate for a can via the thermosetting adhesive layer is provided.

In the production method of the present invention, the bonding of the polyester film is performed, for example, by pressing the polyester film to the metal plate for a can heated on the surface on which the thermosetting adhesive layer is formed. Done. In addition, the bottomed cylindrical body is formed on the printed film-coated metal plate,
It is formed by performing any one of drawing, deep drawing, and drawing and ironing.

As described above, the polyester film can easily follow a large deformation at the time of forming the printing film-coated metal plate into a bottomed cylindrical body and can obtain excellent adhesion. The crystallinity in a range of at least 20% of the total thickness of the film from the surface opposite to the metal plate for the can is 20% or less so that damage due to contact with a tool can be reduced; A crystallinity of at least 5% of the total thickness of the film from the outer surface is 2
What is 0% or more is used.

In order for the polyester film to have the above-mentioned structure in terms of crystallinity, the production method of the present invention requires a crystalline polyester resin having a crystallinity of 30% or more, for example, a substantially single crystalline polyethylene terephthalate resin. The metal plate for a can to which the single-layer film made of the above is adhered is set to a temperature not lower than the melting point of the polyester resin forming the film and lower than the decomposition temperature. In this case, the polyester film is heated from the side of the metal plate for the can by the metal plate for the can, and at least 20% of the thickness of the entire film from the surface of the film facing the metal plate for the can. In the range of%, the resin having the crystallinity of 30% or more becomes amorphous, and the crystallinity becomes amorphous or close to 20% or less. Further, on the outer surface side of the polyester film, since the amorphization progresses to some extent because it is far from the metal plate for a can, the initial crystallinity of 30% or more is relatively easily maintained. The crystallinity in the range of at least 5% of the total thickness of the film is 20% or more.

Next, in the production method of the present invention, the metal plate for a can, on which the coating layer is formed, is formed into a bottomed cylindrical body. The forming of the bottomed cylindrical body can be performed by any one of drawing, deep drawing, and drawing and ironing.

When the metal plate for a can is formed into a cylindrical body with a bottom, residual stress is generated in the film forming the coating layer. The residual stress causes the coating layer to peel off when the bottomed cylindrical body is further processed in a later step, so that the residual stress is small as in the case of drawing in which the ratio of the can height to the can diameter is extremely small. Unless the stress can be ignored, it is desirable to take measures to release the residual stress.

Therefore, in the production method of the present invention, the first heating for releasing the residual stress generated in the coating layer after the metal plate for a can is formed on the bottomed tubular body after the metal plate for the can is formed into the bottomed tubular body. Perform processing. The first heat treatment can prevent peeling of the coating layer due to the residual stress in a subsequent step, and can improve adhesion of the coating layer to the metal plate for a can.

The first heat treatment is performed by heating the bottomed cylindrical body to a temperature in the range of 160 to 260 ° C. If the temperature of the heat treatment is less than 160 ° C., the effect of releasing the residual stress cannot be sufficiently obtained, and if the temperature of the heat treatment exceeds 270 ° C., the polyester film may be thermally degraded.

In the manufacturing method of the present invention, when the process of forming the metal plate for a can into a cylindrical body with a bottom is a drawing process in which the ratio of the can height to the can diameter is relatively small, the coating layer is formed. When forming the metal plate for a can into a bottomed tubular body, a flange is formed at the open end of the bottomed tubular body, and the outer peripheral portion of the flange is trimmed to form the bottom. A flange is formed at the opening end of the bottom cylindrical body. Then, the residual stress is released by performing the first heat treatment on the bottomed cylindrical body on which the flange portion is formed.

In this case, following the first heat treatment, the bottomed cylindrical body having the flange portion is given a predetermined shape as additional processing as desired. Processing may be applied. Examples of the processing for imparting the predetermined shape include a body processing for forming a bead on the body, a bottom processing for forming a dome on the bottom, and the like. Residual stress is generated again in the film.

Therefore, the manufacturing method of the present invention comprises a step of performing a process of giving a predetermined shape to the bottomed cylindrical body on which the flange portion is formed, and a step of providing the coating layer after the process of providing the predetermined shape. Performing a second heat treatment for releasing the generated residual stress. By performing the second heat treatment, the residual stress generated by the process of imparting a predetermined shape to the bottomed cylindrical body is released, and the adhesion of the coating layer to the metal plate for a can is further improved. Can be

In the manufacturing method of the present invention, the process of forming the metal plate for a can into a cylindrical body with a bottom may be a deep drawing process or a drawing ironing process in which the ratio of the can height to the can diameter is relatively large. After trimming the open end of the bottomed tubular body to make the can height from the can bottom uniform, a process of giving a predetermined shape to the bottomed tubular body is performed. However, if the trimming is performed on the bottomed tubular body immediately after being formed from the metal plate for a can, the coating layer may be peeled off due to the residual stress. Examples of the processing for providing the predetermined shape include a flange processing for forming a flange portion at the opening end, a body processing, a bottom processing, and the like.
When these processes are performed, residual stress is generated again in the film forming the coating layer.

Therefore, the manufacturing method of the present invention comprises a step of trimming the open end of the bottomed cylindrical body subjected to the first heat treatment, and a step of trimming the trimmed bottomed cylindrical body. The method includes a step of giving a shape, and a step of performing a second heat treatment for releasing a residual stress generated in the coating layer by the process of giving the predetermined shape.

When the trimming is performed as described above, the residual stress generated in the film forming the coating layer after the bottomed cylindrical body is formed from the metal plate for a can in the bottomed cylindrical body. Since it has been released by the first heat treatment,
The coating layer can be prevented from peeling off by the trimming. According to the second heat treatment,
Following the trimming, the residual stress generated by the processing for imparting the predetermined shape to the bottomed cylindrical body is released, and the adhesion of the coating layer to the can metal plate is further improved. be able to.

Therefore, when any one of the second heat treatments further processes the bottomed cylindrical body in a later step, for example, when the retort treatment after canning is performed, the residual heat is removed. The peeling of the coating layer due to the stress can be prevented.

Each of the second heat treatment is performed by the first heat treatment.
For the same reason as the heat treatment of
It is performed by heating to a temperature in the range of 0 to 260 ° C.

Further, in the production method of the present invention, the printed film-coated metal plate is provided with an overcoat layer on the surface of the polyester film adhered to the outer surface of the can of the bottomed cylindrical body. The surface of the film that has been roughened when it is formed into a film can be smoothed. The overcoat layer may be provided at the film stage, or may be provided after the can body is formed, but by providing after the trimming is performed on the bottomed cylindrical body, the portion to be removed by the trimming is provided. Until then, waste of forming the overcoat layer can be eliminated.

[0042]

Next, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. FIG. 1 is an explanatory cross-sectional view showing one configuration example of the two-piece can body according to the present invention, and FIG. 2 is a partial cross-sectional view showing an enlarged part of the two-piece can body shown in FIG. 3 is an explanatory view showing the structure of the polyester film shown in FIG. 2, and FIGS.
5 is a flowchart showing a method for manufacturing a two-piece can according to the present invention.

As shown in FIG. 1, the two-piece can of this embodiment has a coating made of a film of a substantially single polyethylene terephthalate (hereinafter abbreviated as PET) resin which is a crystalline polyester resin on both sides. A can body 3 obtained by forming a metal plate for a can 2 having layers 1a and 1b into a bottomed cylindrical body by drawing and ironing, and a can attached to an open end 4 of the can body 3 And a lid (not shown). The can body 3
After trimming the opening end of the bottomed cylindrical body 5 obtained by the above processing and adjusting it to a predetermined height, the opening end is subjected to neck-in processing and flange processing to form a neck-in part 6 and a flange part. The can lid is wound around the flange 7 after filling the contents.

The coating layers 1a and 1b are, as shown in FIG.
It is formed by bonding a PET film 8 to the metal plate for a can 2 via a thermosetting adhesive layer 9. Here, the coating layer 1a on the outer surface of the can has a configuration in which a printing layer 10 is provided on a PET film 8 and a thermosetting adhesive layer 9 is further provided on the printing layer 8; Coating layer 1
b has a configuration in which only the thermosetting adhesive layer 9 is provided on a plain PET film 10.

As shown in FIG. 3, both of the PET films 8 forming the coating layers 1a and 1b have a range 8a that is at least 20% of the total thickness of the PET film 8 from the surface facing the metal plate 2 for a can. Has a crystallinity of 20% or less, and a range 8b of at least 5% of the total thickness of the PET film 8 from the outer surface has a crystallinity of 20% or more.

Next, a method for manufacturing the two-piece can of this embodiment will be described with reference to FIG. In addition, metal plate 2 for cans
Can be formed into a cylindrical body with a bottom by any one of drawing, deep drawing and drawing and ironing, but drawing and ironing is the most severe in terms of material processing. Therefore, in the present embodiment, a case of drawing and ironing will be described as an example unless otherwise specified.

In the manufacturing method of this embodiment, the biaxially stretched P having a crystallinity of 30% or more and a thickness of 5 to 20 μm is used.
A printing layer 10 is formed on one surface of the ET film 8, and a thermosetting adhesive layer 9 is formed on the printing layer 10. And
As shown in FIG. 4, the PET film 8 on which the thermosetting adhesive layer 9 is formed is adhered to the outer surface of the metal plate 2 via the thermosetting adhesive layer 9 to form the coating layer 1a. Form.

Simultaneously with the formation of the coating layer 1a, a thermosetting adhesive layer 9 is formed on one surface of the same PET film 8 as the PET film 8 forming the coating layer 1a.
By bonding the T film 8 to the inner surface of the metal plate 2 via the thermosetting adhesive layer 9 to form the coating layer 1b,
The structure shown in FIG. 2 including the coating layers 1a and 1b is obtained.

As the metal plate 2, a metal plate generally used for a two-piece can can be used.
004, 5052, 5049, 5182, 50
82-sheet aluminum plate, tin-plated steel plate, island-shaped tin-plated steel plate (TNS), tin-free steel plate (TF
A steel sheet such as S) can be used. When the aluminum plate is used in the manufacturing method of the present embodiment, since the proof stress is reduced by the heat treatment described below, it is desirable to select a material in anticipation of the decrease in the proof stress.

The thickness of the metal plate 2 is an aluminum plate,
It is suitable for both steel sheets to be in the range of 0.15 to 0.30 mm, and more desirably in the range of 0.15 to 0.26 mm. If the thickness of the metal plate 2 is less than 0.15 mm, the metal plate 2 itself may be damaged by drawing and ironing described below. Moreover, since the bottom of the can is thin, the strength may be insufficient. On the other hand, the thickness of the metal plate 2 is 0.30
If it exceeds mm, the ironing rate must be set high in order to obtain a two-piece can body having a can body of an appropriate thickness by the drawing ironing process described below, and the processing for the PET film 8 becomes severe. . Therefore, the thickness of the metal plate 2 is P
It is preferable that the thickness be 0.26 mm or less so that the treatment of the ET film 8 is not severe.

Further, when the metal plate 2 is drawn and ironed, the original thickness of the metal plate 2 remains at the bottom of the two-piece can body. Therefore, when a thin plate is used, the strength of the bottom decreases. However, it is possible to further reduce the thickness by taking measures such as filling the can with liquid nitrogen to increase the positive pressure. Therefore, the thickness of the metal plate 2 is specifically set to 0.20 mm or less. preferable.

When the PET film 8 is adhered to the metal plate 2 to form the coating layers 1a and 1b, the initial crystallinity of the PET film 8 is set to obtain a mechanical strength that can withstand drawing and ironing described later. Must be at least 30%,
Further, it is preferably at least 40%.

The PET film 8 has a thickness of 5 to 20 μm. If the thickness of the PET film 8 is less than 5 μm, the metal film 2 for a can to which the PET film 8 is adhered may be damaged or a pinhole may be formed when the PET metal film 8 is formed into a bottomed cylindrical body 5 as described later. In some cases, sufficient barrier properties to prevent corrosion of the can body and elution of metal from the contents of the can may not be obtained. When the thickness of the PET film 8 exceeds 20 μm, the residual stress increases when the metal plate for a can 2 to which the PET film 9 is adhered is formed into the bottomed cylindrical body 5 as described later.

As the adhesive used in the present invention, a thermosetting adhesive is suitable, and an adhesive made of a thermoplastic resin is not suitable because it cannot satisfy the severe quality requirements of the present invention.

The adhesive for forming the thermosetting adhesive layer 9 includes at least one resin such as an epoxy resin including a phenoxy resin, a polyester resin, a urethane resin, an acrylic resin, an acid anhydride, an aminoplast, and the like. And a resin composition comprising a curing agent such as a urethane-based curing agent. The adhesive is obtained by dissolving the resin composition in a solvent and bonding the PET film 8 to the PET film 8 adhered to the inner surface of the can.
In the case of the PET film 8 to be adhered to the T film 8 and to the outer surface of the can, the PET film 8 is applied to the printing layer 10 provided on one side of the PET film 8 and heated at a temperature lower than the curing temperature of the adhesive. Thus, the solvent is removed to form the thermosetting adhesive layer 9.

PET having the thermosetting adhesive layer 9 formed thereon
It is preferable that the thermosetting adhesive layer 9 has a tack-free property so that the film 8 can be wound up and stored when it is long. As the adhesive capable of obtaining the tack-free property, specifically, a resin composition composed of an epoxy resin containing a phenoxy resin and an acid anhydride or a resin composition composed of a polyester resin and an aminoplast or urethane-based curing agent There is.

The printing layer 10 is suitable for imparting cosmetics and required display to the outer surface of the can when the metal plate 2 for a can to which the PET film 8 is adhered is formed into a bottomed cylindrical body 5 by drawing and ironing. It is printed so that a perfect pattern can be obtained. The printing is performed by multicolor printing in which the printing ink is laminated for each color by gravure printing using a printing ink composed of a resin composition containing pigments of required colors.

The resin constituting the printing ink includes:
For example, a resin composed of one or more of polyurethane resin, polyester resin, polyester polyurethane resin, epoxy resin, epoxy butyral resin, vinyl resin, cellulose resin, polyisocyanate resin and the like can be mentioned. The resin constituting the printing ink is desirably selected according to the type of the resin constituting the thermosetting adhesive layer 9. For example, the thermosetting adhesive layer 9 is formed of a phenoxy resin and an acid anhydride-based curing agent. When it consists of, it is preferable to consist of an epoxy butyral resin or a polyester polyurethane resin and a polyisocyanate resin. The PET film 8 is formed by using a printing ink comprising the resin and a pigment for the thermosetting adhesive layer 9 comprising the phenoxy resin and the acid anhydride-based curing agent.
Is adhered to the metal plate for a can 2 via the thermosetting adhesive layer 9, a strong adhesive force is obtained by heating at a high temperature for a short period of time. It is also possible to prevent the PET film 8 from peeling off from the metal plate 2 during the retort sterilization treatment after filling with.

The printed layer 10 may be a printed pattern in which a portion that does not require aesthetic or required display, such as the bottom of the bottomed cylindrical body 5, is colored.

The PE on which the thermosetting adhesive layer 9 is formed
The adhesion of the T film 8 to the metal plate 2 is performed, for example, by pressing the PET film 8 to the surface of the heated metal plate 2 on the surface on which the thermosetting adhesive layer 9 is formed.

Next, in the manufacturing method of this embodiment, as shown in FIG. 4, the metal plate 2 on which the PET film 9 is adhered and the coating layer 1 is formed is heated by induction heating or the like.
By maintaining itself at 270 ° C or higher for a short time, PE
The T film 9 is heated from the inner surface side facing the metal plate 2 for a can, and the portion closer to the surface of the surface facing the metal plate 2 becomes amorphous (amorphized) and the crystallinity decreases.

As a result, as shown in FIG. 3, the PET film 8 has a crystallinity of 20% or more in a range 8b of at least 5% of the entire thickness of the PET film 8 from its outer surface, PE from the surface facing the metal plate 2
A range 8a of at least 20% of the total thickness of the T film 8
Has a crystallinity of 0 to 20%.

The time for keeping the metal plate 2 at the above-mentioned temperature is set so that the crystallinity in the above range 8b is kept at 20% or more. In addition, the crystallinity is lower as the surface of the surface facing the metal plate 2 is closer, and is formed with a gradient closer to the crystallinity of the starting level as the surface is closer to the outer surface. Is not clear.

Next, in the manufacturing method of the present embodiment, as shown in FIG. 4, the metal plate 2 on which the coating layer 1 having the crystallinity is formed is punched into a disk having a predetermined diameter, and After forming into a bottom, a drawing and ironing process is performed at an ironing rate of 67% or less to form a bottomed cylindrical body 5 shown in FIG. The drawing and ironing can be performed according to a conventional method using a punch and a die.

The ironing rate is obtained by calculating the original thickness of the metal plate 2 by t.
_{1. When} the thickness after drawing and ironing is t ₂ , the amount is expressed by the following equation. If the thickness exceeds 67%, the processing of the PET film 8 becomes severe and may cause damage or pinholes. In addition, since the metal plate 2 itself may be damaged, the ironing rate is preferably set to 67% or less. In particular, when the workability of the film and the metal material must be considered, the content is more preferably 60% or less.

Ironing rate (%) = (t ₁ −t ₂ ) / t ₁ × 100 Next, in the manufacturing method of the present embodiment, as shown in FIG. By performing the first heat treatment at a temperature of 160 to 270 ° C., the residual stress generated in the PET film 8 by the drawing and ironing process is released.

Next, in order to make the bottomed cylindrical body 5 have a predetermined height, trimming is performed to trim the opening end, and neck-in processing and flange processing are performed on the opening end to form the opening. The end portion is reduced in diameter to form a neck-in portion 6, and a flange portion 7 for winding a can lid around the reduced-diameter opening end portion is formed. As a result, the can body 3 shown in FIG. 1 is formed.

Next, by subjecting the can body 3 to a second heat treatment at a temperature of 160 to 270 ° C., the residual stress generated in the PET film 8 by the neck-in processing and the flange processing is released.

After the can body 3 is filled with the contents, the can 7 is prepared by winding a separately prepared can lid (not shown) around the flange 7.

Next, examples and comparative examples of the present invention will be described.

[0071]

Embodiment 1 In this embodiment, first, a single layer of a single PET
A printing layer 10 is formed on one surface of a long biaxially stretched PET film 8 having a crystallinity of 45% and a thickness of 12 μm made of resin, and a thermosetting adhesive layer 9 is further formed on the printing layer 10. To form a printed PET film 8. The printing layer 10 is formed by laminating a plurality of printing inks composed of an epoxy butyral resin and a polyisocyanate resin and including a resin composition containing a pigment of a required color for each color by gravure printing, thereby forming a four-color printing ink. It is formed by performing color printing. The printing layer 10 has an appropriate pattern that imparts aesthetics and required display to the outer surface of the can when the metal plate 2 for a can to which the printing film is adhered is formed into a bottomed cylindrical body 5 by drawing and ironing. Is printed so as to obtain The thermosetting adhesive layer 9 is formed by applying an adhesive solution obtained by dissolving a resin composition containing a phenoxy resin and an acid anhydride at a weight ratio of 95/5 in a solvent onto the print layer 10, By heating at a temperature lower than the thermosetting temperature of the agent to remove the solvent, a film having a thickness of 1 μm is formed. The thermosetting adhesive layer 9 formed as described above is uncured and has tack-free properties.

Next, a long biaxially stretched PET composed of a single layer of a single PET resin and having a crystallinity of 45% and a thickness of 12 μm is used.
On one surface of the film 8, a thermosetting adhesive layer 9 is applied,
After forming, a plain PET film 8 was produced. The thermosetting adhesive layer 9 used for the plain PET film 8 includes:
The thermosetting adhesive layer 9 of the plain PET film 8 is the same as that used for the printed PET film 8.
Is also uncured and tack free.

Next, a long aluminum plate 2 (aluminum 3004 material) having a thickness of 0.25 mm was heated to 190 ° C., and the printed PET film 8 was placed on the outer surface of the can of the aluminum plate 2. On the inside of the can, the plain PE
The thermosetting adhesive layer 9 is cured and bonded by pressing the T film 8 with a roll via the thermosetting adhesive layer 9, respectively, and the coating layer 1 made of the PET film 8 is bonded.
The aluminum plate 2 provided with a and 1b was manufactured.

Next, the aluminum plate 2 is heated to 270 to 320 ° C. by induction heating and held for a short time.
Quenched from the outside. As a result, both the printed or plain PET films 8 are PET from the outer surface.
The crystallinity in the range 8b of 5% of the total thickness of the film 8 is 3
0% or more, and from the surface of the surface facing the aluminum plate 2 to 7% of the total thickness of the PET film 8.
The crystallinity in the range 8a of 0% was 20% or less, and the aluminum plate 2 covered with the PET films 8 was obtained.

Next, the aluminum plate 2 was punched into a disk shape having a diameter of about 140 mm using a lubricant, formed into a cup shape, and then drawn and ironed in accordance with a standard method to obtain a bottomed iron having an ironing rate of approximately 64%. A cylindrical body 5 was formed. Next, after the lubricant adhering to the bottomed tubular body 5 is removed by washing, the bottomed tubular body 5 is subjected to a heat treatment of heating at a temperature of 220 ° C. for 1 minute, The residual stress generated in the PET film 8 by the drawing and ironing process was released.

Next, after trimming the opening end of the bottomed cylindrical body 5, neck-in processing and flange processing are performed on the opening end to form a neck-in part 6 and a flange part 7. 200g of can body 202 diameter, flange 200 diameter
A can body 3 for a two-piece can body was formed. Next, the can body 3 was subjected to a heat treatment of heating at a temperature of 220 ° C. for 1 minute to release the residual stress generated in the PET film 8 by the neck-in processing and the flange processing.

Table 1 shows the results of evaluating the properties of the PET film 8 in the can body 3 of the present example, together with the structure of the can body 3. “Crystallinity A” in the column of “Configuration of Can Body” in Table 1 means 20% of the thickness of the entire PET film 8 from the surface of each PET film 8 on the inside and outside of the can facing the metal plate 2. % Indicates a crystallinity in a range 8a, and “crystallinity B” indicates a crystallinity in a range 8b of 5% of the total thickness of the PET film 8 from the surface on the side facing the metal plate 2.
Further, the “film appearance” in the column of “outer surface film” and “inner surface film” in Table 1 refers to the bottomed cylindrical body 5.
Shows the presence or absence of scratches and peeling of each PET film 8 on the inner and outer surfaces of the can immediately after formation.
The adhesiveness of each PET film 8 to the metal plate 2 immediately after formation, the “film adhesiveness B” refers to the adhesiveness of each PET film 8 to the metal plate 2 immediately after trimming, and the “film adhesiveness C” refers to the neck. The adhesion of each PET film 8 to the metal plate 2 immediately after the in-processing and the flange processing is shown.

Next, the can body 3 obtained in this example was filled with coffee as a content, and a small amount of liquid nitrogen for applying a positive pressure was injected into the can, and then separately manufactured. Seal using a can lid covered with PET film on the inner surface,
A positive pressure can was prepared, and a retort treatment (heat sterilization treatment) of heating at 125 ° C. for 30 minutes was performed. Immediately after the retort treatment, the can was opened, and the adhesion of the PET film 8 after the retort treatment was evaluated.

After storing the cans at 37 ° C. for 6 months, the cans were opened and the properties of the film and the contents were evaluated.
The results are shown in Table 1. "Retort resistance" in the column of canned in Table 1 means the film adhesion of the PET film 8 on the inner surface side of the can after retort treatment, the presence or absence of peeling, the presence or absence of whitening,
The "Film adhesion D" indicates the overall judgment of the presence or absence of lifting, and the "film adhesion D" refers to the adhesion of the PET film 8 on the outer surface of the can to the metal plate 2 after retort processing.
Means PE on the inner surface of the can with respect to the metal plate 2 after retort processing
The adhesion of the T film 8 is shown.

The evaluation of each item was visually performed according to the following criteria. (1) Film appearance ：: There is no scratch or peeling of the film.

Δ: Slight scratches and peeling of the film are observed.

×: There are scratches and peeling of the film. (2) Film adhesion ○: No peeling of the film.

Δ: Slight peeling of the film was observed.

×: The film is remarkably peeled. (3) Contents ○: No abnormality in flavor.

Δ: Very slightly abnormal flavor.

X: Flavor is abnormal.

[0087]

Embodiment 2 In this embodiment, the aluminum 3 of Embodiment 1 is used.
In place of the aluminum plate 2 made of 004 material, the plate
A can body 3 was formed in exactly the same manner as in Example 1 except that an aluminum plate 2 made of a 25 mm aluminum 5182 material was used. Table 1 shows the results of evaluating the properties of the PET film 8 in the can body 3 of the present example, together with the configuration of the can body 3.

Next, using the can body 3 obtained in the present example, a positive pressure can was produced in exactly the same manner as in Example 1. The cans were opened immediately after the retort treatment, and the results of evaluating the adhesion of the PET film 8 after the retort treatment and the properties of the film and the contents were evaluated by storing the cans at 37 ° C. for 6 months and then opening the cans. Table 1 also shows the evaluation results.

[0089]

Example 3 In this example, a polyester resin and a urethane-based curing agent were used in place of the resin composition containing the phenoxy resin and the acid anhydride in a weight ratio of 95/5 in Example 1 and 90/50.
The can body 3 was formed in exactly the same manner as in Example 1 except that the thermosetting adhesive layer 9 was formed using a resin composition containing the resin composition in a weight ratio of 10. Table 1 shows the results of evaluating the properties of the PET film 8 in the can body 3 of the present example, together with the configuration of the can body 3.

Next, using the can body 3 obtained in this example, a positive pressure can was produced in exactly the same manner as in Example 1. The cans were opened immediately after the retort treatment, and the results of evaluating the adhesion of the PET film 8 after the retort treatment and the properties of the film and the contents were evaluated by storing the cans at 37 ° C. for 6 months and then opening the cans. Table 1 also shows the evaluation results.

[0091]

[Embodiment 4] In this embodiment, the aluminum 3 of Embodiment 1 is used.
Aluminum plate 2 made of 004 material and having a thickness of 0.25 mm
The can body portion 3 was formed in exactly the same manner as in Example 1 except that a TFS (tin-free steel) plate having a plate thickness of 0.21 mm was used instead. Table 1 shows the results of evaluating the properties of the PET film 8 in the can body 3 of the present example, together with the configuration of the can body 3.

Next, using the can body 3 obtained in the present example, a positive pressure can was produced in exactly the same manner as in Example 1. The cans were opened immediately after the retort treatment, and the results of evaluating the adhesion of the PET film 8 after the retort treatment and the properties of the film and the contents were evaluated by storing the cans at 37 ° C. for 6 months and then opening the cans. Table 1 also shows the evaluation results.

[0093]

Fifth Embodiment In this embodiment, the aluminum 3 of the first embodiment is used.
Aluminum plate 2 made of 004 material and having a thickness of 0.25 mm
A can body portion 3 was formed in exactly the same manner as in Example 1 except that a tin-plated steel sheet having a thickness of 0.18 mm and tin distributed in an island shape was used instead. PET in the can body 3 of this embodiment
Table 1 shows the results of evaluating the properties of the film 8 together with the configuration of the can body 3.

Next, using the can body 3 obtained in this example, a positive pressure can was produced in exactly the same manner as in Example 1. The cans were opened immediately after the retort treatment, and the results of evaluating the adhesion of the PET film 8 after the retort treatment and the properties of the film and the contents were evaluated by storing the cans at 37 ° C. for 6 months and then opening the cans. Table 1 also shows the evaluation results.

[0095]

Embodiment 6 In this embodiment, a two-piece can was manufactured by drawing. Next, a method for manufacturing a two-piece can according to the present embodiment will be described with reference to FIG.

In this embodiment, first, a single layer of a single PET
A printing layer 10 is formed on one surface of a long biaxially stretched PET film 8 having a crystallinity of 45% made of resin and a thickness of 20 μm, and a thermosetting adhesive layer 9 is further formed on the printing layer 10. To form a printed PET film 8.

The printing layer 10 is formed by laminating a plurality of printing inks composed of a resin composition containing an epoxy butyral resin and a polyisocyanate resin and containing pigments of required colors for each color by gravure printing. It is formed by performing multicolor printing of colors. Further, the printing layer 10 has an appropriate pattern that imparts aesthetics and required display to the outer surface of the can when the metal plate 2 for a can to which the printing film is adhered is formed into a bottomed cylindrical body 5 by drawing. It is printed so that it can be obtained, and the bottom of the bottomed tubular body 5 is a printed picture with a color removed. The thermosetting adhesive layer 9 is formed by applying an adhesive solution obtained by dissolving a resin composition containing a phenoxy resin and an acid anhydride at a weight ratio of 95/5 in a solvent onto the print layer 10, By heating at a temperature lower than the thermosetting temperature of the agent to remove the solvent, a film having a thickness of 1 μm is formed. The thermosetting adhesive layer 9 formed as described above is uncured and has tack-free properties.

Next, a long biaxially stretched PET composed of a single layer of a single PET resin and having a crystallinity of 45% and a thickness of 20 μm is used.
On one surface of the film 8, a thermosetting adhesive layer 9 is applied,
After forming, a plain PET film 8 was produced. The thermosetting adhesive layer 9 used for the plain PET film 8 includes:
The thermosetting adhesive layer 9 of the plain PET film 8 is the same as that used for the printed PET film 8.
Is also uncured and tack free.

Next, as shown in FIG. 5, the printed or plain PET film 8 was adhered to both surfaces of the metal plate 2. In this embodiment, the metal plate 2 has a thickness of 0.18 mm.
Using a long TFS plate 2 (DR-8C material)
The plate 2 was heated to 190 ° C., and the printed PET film 8 was placed on the outer surface of the TFS plate 2 and the plain PET film 8 was placed on the inner surface of the can. Then, the thermosetting adhesive layer 9 was cured and adhered by pressing with a roll through the, and the TFS plate 2 provided with the coating layers 1 a and 1 b made of the PET film 8 was manufactured.

Next, as shown in FIG.
Was heated and then rapidly cooled to form a predetermined crystallinity distribution in the PET film 8. Specifically, the treatment was performed by heating the TFS plate 2 to 270 to 320 ° C. by induction heating, holding the TFS plate 2 for a short time, and then rapidly cooling it from the outer surface. As a result, both the printed or plain PE
The T film 8 is a PET film 8 from the outer surface.
The degree of crystallinity in the range 8b of 5% of the total thickness is maintained at 30% or more, and the crystal in the range 8a of 70% of the total thickness of the PET film 8 from the surface facing the TFS plate 2 The TFS plate 2 having a degree of conversion of not more than 20% and being covered with the PET films 8 was obtained.

Next, as shown in FIG. 5, the TFS plate 2 was punched out into a disk shape having a diameter of about 132 mm using a lubricant, and then drawn into a cup shape according to a standard method. At this time, a flange is formed in the opening at the same time, and the outer periphery of the flange is trimmed to leave a flange.
A two-piece can body having a length of 4 mm and a can height of 38 mm and having a flange at the opening was formed. Next, as shown in FIG. 5, by subjecting the bottomed cylindrical body to a first heat treatment of heating at a temperature of 220 ° C. for one minute, the residual stress generated in the PET film 8 by the drawing process is released. I was sorry.

In the two-piece can of this embodiment, the flange portion is formed by trimming from the flange portion left at the opening end of the bottomed cylindrical body during drawing as described above. The second heat treatment shown in FIG. 4 is unnecessary. However, if desired, additional processing such as body processing, bottom processing, etc. may be performed to impart a predetermined shape to the bottomed cylindrical body on which the flange portion is formed. Performs a second heat treatment after the additional processing. The second heat treatment can be performed in a manner similar to that of the first heat treatment.

Table 1 shows the results of evaluation of the properties of the PET film 8 in the can body of this example, together with the structure of the can body.

Next, as shown in FIG. 5, the can body obtained in this example was filled with water and salmon fillets as contents.
A separately manufactured inner surface was sealed using a can lid in which a PET film was coated to form a can, and a retort treatment (heat sterilization treatment) of heating at 110 ° C. for 80 minutes was performed. Immediately after the retort treatment, the can was opened, and the adhesion of the PET film 8 after the retort treatment was evaluated.

The cans were stored at 37 ° C. for 6 months, opened, and the properties of the film and the contents were evaluated.
The results are shown in Table 1.

[0106]

[Embodiment 7] In this embodiment, the plate thickness of the embodiment 6 is 0.18 m.
Example 6 except that an aluminum plate (GF14-H19) having a thickness of 0.25 mm was used instead of the TFS plate 2 having a thickness of 0.2 m.
The aluminum plate 2 covered with the printed PET film 8 on the outer surface of the can and the plain PET film 8 on the inner surface of the can was obtained in exactly the same manner.

Next, the aluminum plate 2 is set to a diameter of about 15 mm.
After punching into a 0 mm disk shape, a cup-shaped drawing process is performed according to a standard method, and at the same time, a neck-out portion and a flange-shaped portion are formed in the opening, and the can bottom diameter is 76 mm, the opening diameter is 8 mm.
A can body (a drawn can) was formed in exactly the same manner as in Example 6 except that a tapered bottomed cylindrical body having a flange height of 3 mm and a cannula was left at the opening. Table 1 shows the results of evaluating the properties of the PET film 8 in the can body of this example, together with the configuration of the can body.

Next, using the can body obtained in this example, a can was prepared in exactly the same manner as in Example 6. The can is opened immediately after the retort treatment and the PE after the retort treatment is opened.
The result of evaluating the adhesion of the T film 8 and the above
After storing at 7 ° C. for 6 months, the can was opened and the results of evaluating the properties of the film and the contents are shown in Table 1.

[0109]

Embodiment 8 In this embodiment, a two-piece can was manufactured by deep drawing. Next, a method for manufacturing a two-piece can according to the present embodiment will be described with reference to FIG.

In the present embodiment, firstly, a printed pattern is obtained on the outer surface of the can which can provide an appropriate pattern for imparting aesthetics and required display when formed into a bottomed cylindrical body by deep drawing. Is the printed P, exactly as in Example 6.
An ET film 8 and a plain PET film 8 were prepared.

Next, as shown in FIG. 6, the printed or plain PET film 8 is adhered to both surfaces of the metal plate 2 in exactly the same manner as in Example 6, and the printed PET film is formed on the outer surface of the can. The TFS plate 2 covered with the film 8 and the plain PET film 8 on the inner surface side of the can was obtained.

Next, as shown in FIG. 6, the TFS plate 2 was punched out into a disk shape having a diameter of about 180 mm using a lubricant, and then subjected to deep drawing according to a standard method. In the deep drawing, first, the TFS plate 2 punched into a disk shape is subjected to shallow drawing in a cup shape, and then to the bottom portion, while performing a redrawing process in which the body portion is stretched so as to be thinned. Was performed. As a result, the can diameter was 66 mm.
Was obtained. Next, as shown in FIG. 6, by subjecting the bottomed cylindrical body 5 to a heat treatment of heating at a temperature of 220 ° C. for 1 minute, the residual stress generated in the PET film 8 by the deep drawing is released. Was.

Next, as shown in FIG.
After trimming the opening end of the above, the opening end is subjected to neck-in processing and flange processing to form a neck-in part 6 and a flange part 7, and a can body part for a two-piece can body having a can height of 122 mm. 3 (deep drawn can) was formed.

[0114] Next, as shown in FIG.
By performing a heat treatment of heating at a temperature of 00 ° C. for 1 minute, the residual stress generated in the PET film 8 by the neck-in processing and the flange processing was released.

Table 1 shows the results of the evaluation of the properties of the PET film 8 in the can body 3 of this example, together with the structure of the can body 3.

Next, as shown in FIG. 6, the can body 3 obtained in this embodiment is filled with coffee as a content, and a small amount of liquid nitrogen for applying a positive pressure is injected into the can. After that, a separately manufactured SOT with an inner surface covered with a PET film
(Stay-on-tab) The container was sealed using a can lid, made into a positive pressure can, and subjected to a retort treatment (heat sterilization treatment) of heating at 125 ° C. for 30 minutes. Immediately after the retort treatment, the can was opened, and the adhesion of the PET film 8 after the retort treatment was evaluated.

Further, the cans were stored at 37 ° C. for 6 months, opened, and the properties of the film and the contents were evaluated.
The results are shown in Table 1.

[0118]

[Embodiment 9] In this embodiment, except that an overcoat layer (not shown) was provided on the bottomed cylindrical body 5 obtained in Embodiment 8, the can body 3 was formed in exactly the same manner as in Embodiment 8. Was formed. The above-mentioned overcoat layer is formed on the surface of the PET film 8 adhered to the outer surface of the can before trimming the bottomed cylindrical body 5 obtained in Example 8 and then performing neck-in processing and flange processing. An overcoating agent made of a thermosetting polyester resin was applied and baked at 205 ° C. for 30 seconds to form. The result of evaluating the properties of the PET film 8 in the can body 3 of the present example is
Table 1 shows the configuration of the can body 3.

Next, using the can body 3 obtained in this example, a positive pressure can was produced in exactly the same manner as in Example 8. The cans were opened immediately after the retort treatment, the results of the evaluation of the adhesion of the PET film 8 after the retort treatment, and the cans were stored at 37 ° C. for 6 months, and then opened. Table 1 also shows the evaluation results.

[0120]

COMPARATIVE EXAMPLE 1 In this comparative example, a can body was formed in exactly the same manner as in Example 1 except that a thermoplastic polyester resin-based adhesive layer was formed instead of the thermosetting adhesive layer 8 of Example 1. 3 was formed. Table 1 shows the results of evaluating the properties of the PET film 8 in the can body 3 of this comparative example, together with the configuration of the can body 3.

In the can body part 3 obtained in this comparative example, the PET film 8 shows a certain degree of adhesion to the aluminum plate 2 at the point after the drawing and ironing, but its appearance is It was determined that the ironing process was severely damaged and that it was unusable. Therefore, for the can body 3 obtained in this comparative example, processing after the drawing and ironing,
The evaluation of the treatment was discontinued.

[0122]

Comparative Example 2 In this comparative example, the distribution of the crystallinity of the PET film 8 of Example 1 was replaced with a range of at least 20% of the total thickness of the PET film 8 from the surface facing the aluminum plate 2. A can body 3 was formed in exactly the same manner as in Example 1 except that the crystallinity of 8a was set to 40% or more.
Table 1 shows the results of evaluating the properties of the PET film 8 in the can body 3 of this comparative example, together with the configuration of the can body 3.

Next, using the can body 3 obtained in this comparative example, a positive pressure can was produced in exactly the same manner as in Example 1. The cans were opened immediately after the retort treatment, and the results of evaluating the adhesion of the PET film 8 after the retort treatment are also shown in Table 1.
Shown in

The canned product obtained in this comparative example was inferior in retort resistance, and the PET film 8 was peeled off from the aluminum plate 2 immediately after the retort treatment, and it was judged that the canned product was not usable for canning. . Therefore, the canned product obtained in this comparative example was not stored as in Example 1,
The evaluation was discontinued immediately after the retort treatment.

[0125]

Comparative Example 3 In this comparative example, the degree of crystallinity 45 of a single PET resin was changed in place of the PET film 8 of Example 1.
%, Except that a film having a two-layer structure was formed by laminating an amorphous copolyester film having a thickness of 3 μm on one surface of a long biaxially stretched PET film having a thickness of 12 μm. The can body 3 was formed in exactly the same manner as in the above. Table 1 also shows the results of evaluating the properties of the PET film 8 in the can body 3 of this comparative example.

The canned product obtained in this comparative example was inferior in retort resistance, and the PET film 8 was peeled off from the aluminum plate 2 immediately after the retort treatment, and it was judged that the PET film 8 was not usable for canning. . Therefore, the canned product obtained in this comparative example was not stored as in Example 1,
The evaluation was discontinued immediately after the retort treatment.

[0127]

[Table 1]

From Table 1, it can be seen that the can body obtained in each embodiment according to the present invention and the two-piece can obtained from the can body were as follows.
It is clear that the PET film 8 has excellent adhesion to the metal plate 2. In addition, in the two-piece can body obtained in each of the examples according to the present invention, the appearance of the PET film 8 with respect to the metal plate 2 is excellent, and therefore, the outer surface of the can has PE.
The printed layer 10 formed between the T film 8 and the thermosetting adhesive layer 9 is protected by the PET film 8, and an excellent appearance quality sufficient to provide aesthetics and required display is obtained. It is clear that.

On the other hand, in the can body 3 of Comparative Example 1 using a thermoplastic polyester resin adhesive, as described above, the PET film 9 was already drawn after the drawing and ironing process.
Is severely damaged in appearance. Further, the cans of Comparative Example 2 in which the crystallinity of the PET film 9 on the side facing the metal plate 2 exceeds 20% and Comparative Example 3 in which a laminated film composed of the PET film and the non-crystalline copolyester film is used According to the torso part 3, the adhesion of the PET film 9 to the metal plate 2 is inferior at each stage after the drawing and ironing processing, the trimming processing, the neck-in processing and the flange processing, and the PET film 9 is made of metal after the retort processing. Board 2
It is clear that none of them can withstand use as cans.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view showing one configuration example of a two-piece can body according to the present invention.

FIG. 2 is a partial sectional view showing a part of the two-piece can body shown in FIG. 1 in an enlarged manner.

FIG. 3 is an explanatory view showing a configuration of the polyester film shown in FIG. 2;

FIG. 4 is a flowchart showing a method for manufacturing a two-piece can body of the present invention.

FIG. 5 is a flowchart showing a method for manufacturing a two-piece can according to the present invention.

FIG. 6 is a flowchart showing a method for manufacturing a two-piece can according to the present invention.

[Explanation of symbols]

2: metal plate for cans, 5: tubular body with bottom, 8: polyester film, 9: thermosetting adhesive layer, 10: printing layer.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B32B 5/14 B32B 5/14 B65D 25/34 B65D 25/34 Z C09J 163/02 C09J 163/02 (72 ) Inventor Koji Matsushima 4-5-15 Ueno, Iwatsuki-shi, Saitama F-term in the Technology Division of Hokkai Seikan Co., Ltd. AK51C AK53C AK54C AL05C BA04 BA05 BA07 BA10A BA10D BA42 CA02C CB00C CB00G CC00E DA01 DB09 EC182 EH012 EH46 EH462 EJ172 EJ263 EJ422 EK172 GB16 GB23 HB31B JA11D JB13C JB13G JE04 E02D01 001 001 001 MB03 MB05 NA06

Claims (21)

[Claims] 1. A polyester film provided with a printing layer and a thermosetting adhesive layer laminated on the printing layer on at least one side of a metal plate for a can which is to be an outer surface of the can. A two-piece can body formed by molding a printed film-coated metal plate adhered via an adhesive layer into a bottomed cylindrical body. 2. A polyester film having a thermosetting adhesive layer on one surface of the metal plate for a can on the side serving as the inner surface of the can, the polyester film being bonded via the thermosetting adhesive layer. The two-piece can according to claim 1, wherein 3. The polyester film is a single-layer film made of a crystalline polyester resin, and has a thickness of at least 20% of the total thickness of the film from the surface facing the metal plate for a can. At least 5% of the total thickness of the film from the outer surface
3. The two-piece can according to claim 1, wherein the degree of crystallinity in the range is 20% or more. 4. The two-piece can according to claim 3, wherein said polyester film is substantially made of a single polyethylene terephthalate resin. 5. The thermosetting adhesive is a resin composition comprising an epoxy resin containing a phenoxy resin and an acid anhydride or a resin composition comprising a polyester resin and an aminoplast or urethane-based curing agent. The two-piece can according to any one of claims 1 to 4, characterized in that: 6. The method according to claim 1, wherein an overcoat layer is provided on the surface of the polyester film adhered to the outer surface of the can of the bottomed cylindrical body. Two-piece can. 7. A printing layer having an appropriate pattern when a bottomed tubular body is formed from the metal plate for a can, at least on a side of the metal plate for the can which is to be the outer surface of the can, and a printing layer laminated on the printing layer. Bonding a polyester film provided with the thermosetting adhesive layer on one surface thereof through the thermosetting adhesive layer to form a printed film-coated metal plate; and Forming a bottom tubular body. 8. A method for adhering a polyester film having a thermosetting adhesive layer on one surface thereof to the inner side of a metal plate for a can through the thermosetting adhesive layer. The method for producing a two-piece can according to claim 7, wherein: 9. The polyester film having a crystallinity of 3
A single-layer film of 0% or more of a crystalline polyester resin, wherein the metal plate for a can to which the film is adhered is set to a temperature equal to or higher than the melting point of the polyester resin forming the film and lower than the decomposition temperature; The film is heated from the side of the metal plate for a can by the metal plate for a can, and the crystallinity of the film is at least 20% of the total thickness of the film from the surface of the film facing the metal plate for the can. 9. The method according to claim 7, further comprising the step of setting the crystallinity in the range of at least 5% of the total thickness of the film from the outer surface to not less than 20%. 2
A method for manufacturing a piece can. 10. The method for manufacturing a two-piece can according to claim 9, wherein said polyester film is substantially made of a single polyethylene terephthalate resin. 11. The bottomed tubular body is formed by subjecting the printed film-coated metal plate to one of drawing, deep drawing, and drawing and ironing. The method for producing a two-piece can according to any one of claims 7 to 10. 12. A method according to claim 1, wherein said bottomed tubular body is subjected to a first heat treatment for releasing a residual stress generated in said coating layer after forming said metal plate for a can into said bottomed tubular body. The method for producing a two-piece can according to any one of claims 7 to 11. 13. The method for manufacturing a two-piece can according to claim 12, wherein in the first heat treatment step, the bottomed cylindrical body is heated to a temperature in the range of 160 to 260 ° C. 14. When forming the metal plate for a can on which the coating layer is formed into a cylindrical body with a bottom, a flange-like part is formed at an open end of the cylindrical body with a bottom, and the flange-like part is formed. The method for manufacturing a two-piece can according to any one of claims 7 to 13, wherein an outer peripheral portion of the portion is trimmed to form a flange portion at an open end of the bottomed tubular body. . 15. A step of applying a predetermined shape to the bottomed cylindrical body on which the flange portion is formed, and a step of releasing a residual stress generated in the coating layer after the step of applying the predetermined shape. The method for producing a two-piece can according to claim 14, further comprising the step of: 16. The method for producing a two-piece can according to claim 15, wherein the processing for imparting the predetermined shape is a body processing or a bottom processing. 17. A step of trimming an open end of the bottomed cylindrical body subjected to the first heat treatment, and performing a process of imparting a predetermined shape to the trimmed bottomed cylindrical body. 14. The method according to claim 12, further comprising the step of: performing a second heat treatment for releasing a residual stress generated in the coating layer by the processing for imparting the predetermined shape.
A method for manufacturing a piece can. 18. The method for manufacturing a two-piece can according to claim 17, wherein the processing for imparting the predetermined shape is at least one of flange processing, body processing, and bottom processing. . 19. The two-piece can according to claim 15, wherein in the second heat treatment step, the bottomed cylindrical body is heated to a temperature in the range of 160 to 260 ° C. Manufacturing method. 20. The method according to claim 7, further comprising the step of providing an overcoat layer on a surface of the polyester film adhered to the outer surface of the bottomed cylindrical body.
The method for producing a two-piece can according to any one of the above items. 21. The method according to claim 20, wherein the step of providing an overcoat layer on the bottomed tubular body is performed after the trimming is performed on the bottomed tubular body.