JP2002166918A - Can body with printed film stuck thereon and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a can body with a printed film stuck thereon comprising a can body whose barrel and base are integrally molded and a printed resin film stuck to an external surface of the barrel wherein an internal surface of the can body can be protected without causing a problem of elution of bisphenol A into contents of the can, the can body can be well molded without using a large quantity of a lubricant or cleaning water in molding the can body, and in addition an appearance is not degraded with the shrinkage of the printed resin film by a post heating treatment for improving adhesion between the film and the can body. SOLUTION: The can body 1 with a printed film stuck thereon comprises a can body 1A having a barrel 2 and a base 3 integrally molded, and a printed resin film 20 stuck to an external surface of the barrel via an adhesive layer. The can body 1A is integrally molded of a covered metal plate formed with a protective coating of a thermoplastic resin formed on a side of an internal surface of the metal plate, and formed with a protective coating of a curable resin formed on a side of an external surface of the can. The printed resin film 20 is stuck by heat-bonding on the protective coating of the curable resin covered on the external surface of the can body 1 via the adhesive layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed film-adhered can body in which a printed resin film is adhered to an outer surface of a body of a can body having a body and a bottom integrally formed. The present invention relates to a method for manufacturing a printed film-adhered can body, and particularly to a printing method in which a can body before applying a printed resin film is integrally formed from a coated metal plate having both surfaces previously coated with a resin protective coating. The present invention relates to a finished film-adhered can body and a method for producing the same.

[0002]

2. Description of the Related Art An appropriate printing method such as gravure printing or overprinting by offset printing can be applied to a three-piece can in which characters and / or patterns are previously printed on a blank for a plate-shaped can body. On the other hand, in the case of a two-piece can in which the body and the bottom are integrally formed, printing is performed on the body of a can body (a two-piece can body) formed in a cylindrical shape with a bottom. Conventionally, dry offset printing is generally applied because overprinting by printing or offset printing is practically impossible, but in this printing method,
Overprinting with inks of different colors is virtually impossible, and the number of colors and color tones are limited. It is impossible to perform luxurious and elegant decorative printing using multicolor inks.

However, with regard to canned products made of two-piece cans, a more beautiful appearance is required due to diversification of products due to changes in consumption trends and needs, and for this reason, for example, Japanese Patent Application Laid-Open No. 9-29539 and Kaiping 1
As described in 1-1147515 and the like,
Rather than directly printing on the outer surface of the body of the can, beautiful multicolor printing characters and patterns are applied to a thermoplastic resin film such as a biaxially oriented polyester resin film by a gravure printing method in advance. At the same time, an adhesive layer of a thermosetting resin is formed on the inner surface side of the printed resin film (the surface in contact with the outer surface of the body of the can), and the printed resin film is coated with the adhesive layer. Conventionally, it is possible to provide a print design of characters and designs by gravure printing or the like to the outer surface of the body of a two-piece can by attaching it to the outer surface of the body of the can via a heat bonding method. And commercial production has actually been done.

On the other hand, bisphenol A, which is a raw material of thermosetting epoxy resin and phenolic resin, which has been widely used as a coating applied as a protective coating on a metal surface of a can body, has recently entered the human body. Since the theory that it acts like a hormone and adversely affects fertility has been published and has become a problem, protection of thermoplastic resins such as polyester resins, polypropylene resins, polyethylene resins, and polyamide resins that do not contain bisphenol A is protected. The coating is laminated on one side of the metal plate (the metal surface on the inner side of the can) or both surfaces, and from this coated metal plate, the two-piece can body (body and bottom) or the three-piece can body (glass cans) ) And can lids (canopy and bottom lid) were proposed, in fact,
2. Description of the Related Art Two-piece can bodies (can bodies) are manufactured from electrolytic chromic acid-treated steel sheets having a polyester resin film (film) laminated on both sides.

However, after a protective film of a thermoplastic resin such as a polyester resin or a polyolefin resin is coated on only one surface of the metal plate (the metal surface on the inner surface side of the can), it is formed into a cup by drawing. In the case of redrawing and forming into a deep drawn can, or redrawing and then further ironing to form a drawn and ironed can, the other surface of the metal plate (with the outer surface of the can) It is necessary to redraw or iron while applying or spraying a large amount of lubricant on the metal surface). Causes the problem that the cup is seized on the redrawing die or ironing die, the body of the cup is damaged or broken, and the can cannot be continuously formed.

Therefore, when only the metal surface on the inner side of the can of the metal plate is coated with the protective coating of the thermoplastic resin and the opposite metal surface is not coated with the protective coating of the thermoplastic resin, both sides of the metal plate are required. A large amount of lubricant is used as compared with a case where the lubricant is coated with a protective coating of a thermoplastic resin, and a large amount of washing is required since a step of degreasing, chemical conversion, and washing with the lubricant is required. Water is needed, and
It is necessary to apply a new spray coating of thermosetting resin or the like as a protective coating on the bottom of the can body that will not be subjected to characters or patterns by direct printing or pasting of a printed resin film later. (If the protective coating is not applied, the bottom metal surface may corrode during storage of the can body or canned product).

On the other hand, using a coated metal plate whose both surfaces are coated with a protective coating of thermoplastic resin (thermoplastic resin layer), a can body (seamless metal) is drawn and ironed or deep drawn. Can), and applying a printed resin film, which has been subjected to beautiful printing design by gravure printing, to the outer surface side of the body of the can body thus formed by thermal bonding. For example, it is conventionally known, for example, from JP-A-2000-177745.

That is, a high-temperature volatile lubricant (glamor wax) is uniformly applied to a coated metal plate having both surfaces of an aluminum alloy plate coated with a thermoplastic copolyester resin film. At the same time as drawing and ironing, thinning is performed by drawing and ironing, and after forming a deep drawing cup, doming forming is performed according to a conventional method, and then the deep drawing cup is heat-treated to remove processing distortion of the film and wax. It is disclosed in the above-mentioned publication that a can body before the printed resin film is attached is manufactured by volatilizing and removing the resin.

[0009]

By the way, as disclosed in the above publication, a can body is formed from a coated metal plate in which a protective film (thermoplastic resin layer) of a thermoplastic resin is coated on both sides of the metal plate. By integral molding, the amount of lubricant used during molding can be reduced, eliminating the need to use a large amount of washing water to remove the lubricant after molding. It is not necessary to spray a protective coating on the inner surface and outer surface of the can after molding into a squeeze cup. In addition, the protective coating on the inner surface of the can that comes into contact with the contents of the can does not contain bisphenol A thermoplastic. Since the copolyester resin is used, there is an advantage that bisphenol A does not elute into the contents of the can when the can is stored.

On the other hand, as a result of many years of research by the present inventor, it has been found that conventionally known techniques as disclosed in the above publications have the following problems. That is, when the printed resin film is attached to the outer surface of the body of the bottomed cylindrical can body, the can body is previously heated to a temperature equal to or higher than the heat bonding temperature of the adhesive layer formed on the printed resin film. After heating, a printed resin film of the size of each can is placed on the outer surface of the body of the can body, which is attached to the mandrel of the film sticking device, and the adhesive layer side is the body of the can body. The printed resin film is adhered to the can by pressing and adhering with an adhering roll so as to be in contact with the outer surface.

The can body to which the printed resin film is adhered by such a method is usually subjected to neck-in processing for reducing the diameter of the open end side of the cylindrical can body having a bottom by one or more steps, and further to flange processing. Because there is a possibility that the printed resin film stuck during these processes may be peeled off among many can bodies, the printed resin film is adhered to the outer surface of the trunk. After the can body is heated, the activation temperature of the adhesive layer (the activation temperature of the adhesive layer varies depending on the type of resin used in the adhesive layer, but is approximately 15 ° C.).
It is preferable to increase the adhesive strength between the can body and the printed resin film by heating to a temperature of about 0 to 240 ° C.) or more.

However, after the printed resin film is bonded to the can body, the can body is further post-heat treated (for example, 150 ° C.) to increase the adhesive strength between the adhesive layer of the printed resin film and the can body. ~ 240 ° C for about 40 to 240 seconds)
When heated, the printed resin film, in which the printing ink layer, adhesive layer, and lubricant-containing overcoat layer are formed on the surface of the thermoplastic resin (polyester resin) film originally oriented biaxially, is post-heated. When the can is integrally molded from a coated metal plate coated on both sides with a protective coating of a thermoplastic resin (polyester resin), it tends to shrink due to the heat treatment. The protective film of the thermoplastic resin covering the metal surface with the lower layer (layer close to the metal surface) is softened by the post-heating treatment, and the printed resin film on the upper layer is easily softened by the softening of the lower protective film. It will heat shrink.

Therefore, even after the post-heating treatment, the entire cylindrical body of the can body formed into a bottomed cylindrical shape is intended to be covered with the printed resin film. as shown in a), the printed resin film 20 length in the height direction of the can body 1A was L ₁ is when adhered to the can body 1A is, than after the post-heating treatment to a length of L ₂ As shown in FIG. 3B, as a result of heat shrinkage, as a result, between 2 mm and 5 mm from the open end and the lower end of the body of the can 1 </ b> A, respectively (showing the open end of the can Although the outer surface of the can of the metal plate 11 is covered with the protective coating 12 made of a thermoplastic resin, there is a problem that a portion not covered with the printed resin film 20 (a portion where the protective coating 12 is exposed) is formed. . Then, even if it is the open end side, it will not be completely hidden by the can lid tightening portion when the can body is later sealed with the can lid, and will be noticed by the consumer,
At the lower end of the body portion, which is not subjected to any processing that deforms the shape after the printed resin film is adhered, the appearance of the can body is remarkably deteriorated because it can be seen more clearly by consumers.

In particular, a white pigment such as titanium dioxide is mixed in a protective coating of a thermoplastic resin covering a metal surface in order to enhance a printing effect by highlighting a printed design printed on a printed resin film. When the printed resin film is shrunk and shortened, the white protective film exposed on the surface becomes considerably noticeable due to the color contrast with the printed resin film, especially the appearance of the can. The sex gets worse.

An object of the present invention is to solve the above-mentioned problems. Specifically, a printed resin film is attached to the outer surface of the body of a can body having a body and a bottom integrally formed. The inner surface of the can is protected without causing problems due to the dissolution of bisphenol A into the contents of the can, and a large amount of lubricant or washing water is used when forming the can. That the can body can be molded well without the need for heat treatment, and that the printed resin film does not shrink due to post-heating treatment to enhance the adhesion between the printed resin film and the can body, and the appearance does not deteriorate. Is the subject.

[0016]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an outer surface of a body of a can body having a body and a bottom integrally formed as described in claim 1 above. In a printed film-adhered can body having a printed resin film adhered thereto via an adhesive layer, the can body has a protective coating of a thermoplastic resin formed on the inner side of the metal plate, It is integrally formed from a coated metal plate having a protective coating of a curable resin formed on the outer surface, and an adhesive layer is formed on the protective coating of the curable resin coated on the outer surface of the can body. Wherein the printed resin film is bonded by thermal bonding.

Further, in the method of manufacturing such a printed film-adhered can body, as described in claim 2, one surface of the metal plate is coated with a protective coating of a thermoplastic resin, and the other surface is coated with a protective coating of a thermoplastic resin. After applying a high-temperature volatile lubricant to both sides of a coated metal plate whose surface is covered with a protective coating of a curable resin, the surface covered with thermoplastic resin becomes the inner surface of the can, and is cured. First, the coated metal plate is punched and formed into a cup by drawing and drawing so that the surface coated with the conductive resin is the outer surface of the can. After being molded, the can body is heat-treated to volatilize the applied lubricant, and then a printed resin film having an overcoat layer formed on the outer surface and an adhesive layer formed on the inner surface The tree on the outer surface of the body of the heated can. The adhesive layer of the film is bonded by pressing, and then the post-heating treatment is performed on the can body to which the printed resin film is bonded, in order to heat the adhesive layer of the printed resin film to an activation temperature or higher. It is characterized in that it is performed.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of a printed film-adhered can body and a method for producing the same of the present invention will be described in detail with reference to the drawings. FIG. 1 shows the appearance of the printed film pasting can body before and after (A) neck flange processing and (B) the state after neck flange processing, respectively, and FIG. 2 shows (A) a coated metal plate. 3A and 3B show the cross-sectional laminated structures of (B) a printed resin film and (C) a body of a printed film-adhered can body. It should be noted that the dimensions of each part shown in the drawings are merely schematically shown regardless of the actual dimensions.

The printed film-adhered can body of this embodiment is a can body (excluding the can lid) of a two-piece can. As shown in FIG. As shown in FIG. 1B, neck and flange processing (neck-in processing and flange processing) is performed from the bottomed cylindrical shape in which the body 2 and the bottom 3 are integrally formed by drawing and ironing. The upper part of the cylindrical body part 2 is reduced in diameter to the neck part 4 and the flange part 5 is formed at the upper end of the neck part 4. Although not shown, the upper end opening of the body is hermetically sealed by filling the can lid (easy open end) around the flange portion 5 after filling the contents.

Such a printed film sticking can 1
Is a bottomed cylindrical can body formed by deep drawing or drawing and ironing, using a coated metal plate in which both surfaces of a metal plate 11 are covered with resin protective coatings 12 and 13 as shown in FIG. And a printed resin film 20 having a top coat layer 21, a thermoplastic resin film layer 22, a printing ink layer 23, and an adhesive layer 24 as shown in FIG. FIG. 2 shows a state in which the body 2 of the can body formed into a bottomed cylindrical shape by thermal bonding via the layer 24 is adhered to the body 2 of the printed film-laminated can body 1.
As shown in FIG. 1 (C), both surfaces of a metal plate (a metal plate thinned and formed into a shape of a trunk portion) 11 are covered with a resin protective coating 1.
On the outer surface side of the can body 1A covered with
3, a printed resin film 20 is stuck on the resin film.

The printed film-sticking can 1 of the present embodiment as described above will be described in more detail.
1A, one surface of a metal plate 11 is covered with a protective coating 12 of a thermoplastic resin and the other surface is a curable resin (a thermosetting resin, an ultraviolet curable resin, an electron beam curable resin, etc.).
Although not shown, the coated metal plate coated with the protective coating 13 is punched and drawn so that the protective coating 12 of the thermoplastic resin is on the inner surface side of the can. Then, the cup is further redrawn and the body wall thinned to form a bottomed cylindrical can before the printed resin film is adhered.

The metal plate 11, which is the base material of the coated metal plate, is a metal plate for canning which has been conventionally used in a two-piece can, that is, an aluminum alloy plate, a nickel-plated steel plate, a tin-plated steel plate, and a metal plate. Selectively use any surface-treated steel sheet that has been subjected to surface treatment with high adhesion to curable resins and thermoplastic resins, such as thin tin plated steel sheets, electrolytic chromic acid-treated steel sheets, galvanized steel sheets, etc. can do.

The thermoplastic resin which covers one surface (the inner surface side of the can) of such a base metal plate 11 as the protective film 12 is a resin not containing bisphenol A, and has a certain processing resistance and The resin is not particularly limited as long as it has heat resistance, water resistance, gas permeation resistance and the like. However, in consideration of availability and cost, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, Polyester resins such as ethylene terephthalate / isophthalate copolymer, ethylene terephthalate / adipate copolymer, butylene terephthalate / isophthalate copolymer, ethylene naphthalate / terephthalate copolymer, polyethylene, polypropylene, ethylene / propylene copolymer, Polyolefins such as modified olefins Fat, polyamide resin, and a mixed resin or the like of two or more thereof are preferred.

The mode of the protective film 12 of the thermoplastic resin is not limited to a single layer, but may be a multi-layer structure combining different types of resins. As a method of coating the metal sheet 12 with the metal sheet 11, a method of directly laminating a thermoplastic resin film on a pre-heated metal sheet, a method of extruding a softened thermoplastic resin on a pre-heated metal sheet from a T-die and laminating the same. A method of forming an adhesive layer on a thermoplastic resin film and laminating it on a pre-heated metal plate, forming an adhesive layer on a metal plate, and forming a T-die on the pre-heated metal plate. An appropriate method such as a method of extruding a thermoplastic resin from the resin and laminating the same can be employed.

When such a metal plate 11 and a protective film 12 of a thermoplastic resin are laminated via an adhesive layer, the adhesive may be epoxy, hydroxyl, amide, ester, carboxyl, urethane, or the like. Adhesives composed of a single or a mixture of polymers having at least one of an acrylic group and an amino group in a molecule, for example, polyester adhesives, melamine adhesives, polyurethane adhesives, epoxy resin adhesives, Polyamide resin-based adhesives, copolyester resin-based adhesives, acid-modified olefin resin-based adhesives, and the like can be used. Particularly, epoxy-phenol-based adhesives, epoxy-amino-based adhesives, epoxy-acrylic-based adhesives, epoxy- Polyester-amino adhesive, epoxy-polyester-melamine adhesive, epoxy-polyester-phenol adhesive Agents, and the like are suitable.

The curable resin which covers the other surface (the outer surface of the can) of the metal plate 11 as the protective film 13 is applied as a paint, and such a curable resin paint is a thermosetting resin. As long as it is a curable resin paint such as a paint, an ultraviolet curable resin paint, or an electron beam curable resin paint, it can be used as appropriate, and is not particularly limited. Epoxy resin paint, thermosetting acrylic resin paint, polyurethane resin paint, phenol resin paint, furan resin paint, melamine resin paint, urea resin paint, alkyd resin paint, etc. can be suitably used. A mixture of a plurality of different resins, for example, phenol-epoxy paint, amino-epoxy paint, acrylic-epoxy paint, melamine-
Phenol paints, acrylic-phenol paints, epoxy-modified vinyl paints, epoxyamino-modified paints, and ethoxyphenol-modified vinyl paints can also be used.

The printed resin film 20 adhered to the outer surface of the body of the can 1A integrally formed from the coated metal plate
In the present embodiment, as shown in FIG.
A laminated film including a top coat layer 21, a thermoplastic resin film layer 22, a printing ink layer 23, and an adhesive layer 24 is used, and the thermoplastic resin film layer 2 serving as a main layer is used.
2, the printing ink layer 23 is formed on the surface on the side opposite to the top coat layer 21. However, the invention is not limited to this, and the printing ink layer 2 is formed on the surface on the same side as the top coat layer 21.
3 may be formed, and the printing ink layer 23 may be covered with the top coat layer 21.

The thermoplastic resin film layer 22 serving as the main layer of the printed resin film 20 plays a role as a holding portion of the printing ink layer 23, and the printed appearance of characters and patterns to be printed is clear. Since it is necessary to ensure the properties and gloss, it is basically preferable to use a transparent or translucent one, and a post-heating treatment applied to increase the adhesive strength between the can body It is necessary to have heat resistance that can withstand, for example,
Polypropylene resin film, polyamide (nylon)
A resin film, a polyester resin film, or the like can be used. In particular, a biaxially stretched film obtained by orienting and crystallizing a polyester resin is optimal from the viewpoint of transparency and heat resistance.

Specific examples of the polyester resin used for the thermoplastic resin film layer 22 include homopolymer resins such as polyethylene terephthalate (PET), polyethylene isophthalate (PEI) and polybutylene terephthalate (PBT), and ethylene terephthalate. / Isophthalate copolymer, copolymer resin such as butylene terephthalate / isophthalate copolymer, blend resin such as blend resin of polyethylene terephthalate and polyethylene isophthalate, blend resin of polyethylene terephthalate and polybutylene terephthalate, etc. is there.

The top coat layer 21, which is the uppermost layer of the printed resin film 20, prevents the resin film from being damaged due to insufficient slipperiness of the can body, and prevents the resin film from undergoing a physical change during retort treatment, that is, the crystallinity. It is provided to prevent changes in optical characteristics due to changes in water content.
In any case, since the purpose is to ensure the finished appearance of the print, it is necessary not only to have good slipperiness and retort resistance, but also to be a colorless and transparent film layer.

As such a top coat layer 21,
In some cases, a thermosetting resin paint, an electron beam curable resin paint, an ultraviolet curable resin paint, or the like is used, and a lubricating agent such as silicone or wax is further added to further improve the slipperiness. Thermosetting resin paints that can be used as the top coat layer 21 include epoxy-amino resin, epoxy-
There are so-called clear paints such as melamine resin and polyester-amino resin, and as the electron beam-curable resin paint, there are epoxy acrylate resin, polyester acrylate resin, polyurethane acrylate resin, polyether acrylate resin and the like. Not only one kind but also a mixture of two or more kinds can be used.

The UV-curable resin paint is different from the above-mentioned electron beam-curable resin paint.
Monofunctional monomers such as 2-hydroxyethyl acrylate and tetrahydrofurfuryl acrylate, difunctional monomers such as dicyclobenthenyl acrylate and 1,4-butanediol acrylate, and trifunctional monomers such as trimethylolpropane triacrylate As a photopolymerization diluent, one or a mixture of two or more thereof, and further, as a photopolymerization initiator, a coating material of one or more of acetophenone, benzophenone, or the like can be used.

The printing ink layer 23 formed on the back side of the thermoplastic resin film layer 22 is not particularly limited since characters and designs are applied by printing, but a thermosetting urethane resin is used. Ink used as a binder is generally used, and as a printing method,
Various printing methods such as gravure printing, flexo printing, offset printing, etc. can be selected as appropriate, but if you want to print rich colors and beautiful characters and designs using a large number of colors,
Printing is preferably performed by a gravure printing method.

The adhesive layer 24 provided on the lowermost layer of the printed resin film 20 so as to cover the printing ink layer 23 is basically easily adhered to the outer surface of the body of the can body by applying pressure and heat. With an adhesive that can be used, for example,
As the thermosetting adhesive, unsaturated polyester resin, isocyanate resin, amino resin, polyurethane resin, epoxy resin, acrylic resin and the like can be used.
Polyester-epoxy-amino adhesive, epoxy-
Phenol-based adhesives and epoxy-amino-based adhesives can be suitably used, and an electron beam-curable adhesive, a combination of heat curing and electron beam curing, and the like can also be used.

The adhesive forming the adhesive layer 24 is not limited to the above-mentioned adhesive of the resin composition alone, but may be further added to such a resin composition by an inorganic pigment such as titanium oxide or mica. However, if the added amount of the white pigment is too small, the hiding factor becomes insufficient and the influence of the spectral reflectance of the underlying metal appears, so the whiteness is insufficient. While the print appearance becomes bluish color and impairs glossiness and clarity, if the amount of white pigment added is too large, the hiding ratio does not increase and the effect is saturated, so it is not economical, and the adhesive itself is not economical Result in reduced cohesive strength, and rather poor adhesion.

The manufacturing method of the printed film-adhered can body 1 of the present embodiment having the above-described materials as constituent elements will be described below. First, the coated metal plate used as the material of the can body will be described. While laminating a thermoplastic resin film on one side of the strip-shaped metal plate,
By applying a coating of a curable resin (thermosetting resin, ultraviolet curable resin, electron beam curable resin, etc.) on the other surface and curing it, one surface of the metal plate is made of thermoplastic resin. A strip-shaped coated metal plate coated with a protective coating and the other surface coated with a protective coating of a curable resin is manufactured and prepared.

On the other hand, for the printed resin film to be adhered to the body of the can body, a top coat is applied to one side of the belt-shaped thermoplastic resin film serving as the main layer, and then dried, whereby the top coat is dried. While forming a layer,
After applying the desired print design by the appropriate printing method on the opposite side from the top coat application surface and drying to form the printing ink layer, apply and dry the adhesive so as to cover the printing ink layer and bond it By forming the agent layer, a belt-shaped printed resin film is manufactured and prepared.

In the production of a printed resin film, it is preferable that the printing ink layer is sufficiently dried. However, the adhesive layer becomes the adhesive surface on the outer surface of the body of the can body afterwards. In the case of a thermosetting adhesive or an adhesive in which a thermosetting adhesive and an electron beam curable adhesive are used in combination, it is preferable that the adhesive is not completely cured.

Using the strip-shaped coated metal plate manufactured as described above, first, a high-temperature volatile lubricant is uniformly applied to both surfaces of the coated metal plate prior to processing, and then a thermoplastic resin is used. A band-shaped coated metal plate is punched out into a disk of the size of each can and drawn into a cup so that the coated surface is the inner surface of the can and the surface coated with the curable resin is the outer surface of the can. After forming, the cup was further redrawn and thinned (drawing, ironing, stretching, etc.) to form a bottomed cylindrical can, while the cup was manufactured as described above. The strip-shaped printed resin film is cut into a width corresponding to one can, wound up on a reel, and cut into a film sheet of a size corresponding to each can immediately before sticking to a can body.

Next, the high temperature volatile lubricant is volatilized and removed by heating the bottomed cylindrical can body.
In some cases, after further washing with washing water and drying, a conventionally known appropriate film sticking device prints a heated can body on a sheet of the size of each can. The resin film is adhered by pressing the side of the adhesive layer formed on the lowermost layer against the outer surface of the body of the can body, and thereafter, the can further has the printed resin film adhered to the body. The body is subjected to a post-heating treatment for heating to a temperature higher than or equal to the activation temperature of the adhesive layer of the printed resin film, so that the adhesion strength between the can body and the printed resin film is improved. A printed resin film is adhered to the outer surface of the body.

The can body to which the printed resin film is adhered as described above is usually subjected to neck-in processing to reduce the diameter of the open end side of the bottomed cylindrical can body by one or more steps.
Furthermore, since it is subjected to flange processing, there is a possibility that the resin film adhered during these processing may peel off among many can bodies, so it is printed on the outer surface of the trunk as described above The can body after the resin film is adhered is heated to the activation temperature of the adhesive layer (the activation temperature of the adhesive layer varies depending on the type of resin used in the adhesive layer, but is approximately 15 ° C.).
By heating at a temperature of about 0 to 240 ° C. or higher, the adhesive strength between the can body and the resin film is improved.

[0042]

EXAMPLES Specific examples of the method for producing the above-described printed film-adhered can body will be described below. [Example 1] Thickness 0.3 previously heated to 260 ° C
A 1 mm thick aluminum alloy strip for drawing and ironing can has a thickness of 20 made from a polyester resin in which a polybutylene terephthalate resin and a polyethylene terephthalate resin are mixed at a mixing ratio of 60:40 on one surface.
After the biaxially oriented film of μm is continuously applied while being pressed by an application roller, after the temperature of the aluminum alloy strip becomes 50 ° C. or less, the unsaturated polyester resin based After the coating is applied by a roll and dried by passing through an oven, the temperature is further raised to 260 to 270 ° C., and then immediately passed through water to be quenched, whereby the polyester resin layer becomes amorphous. Qualify.

A known high-temperature volatile lubricant (for example,
Normal butyl stearate, dioctyl sebacate,
Liquid paraffin, polyethylene wax, petrolatum, palm oil, etc.) is applied thinly using a gravure roll, and then the coated aluminum alloy strip is punched and sent to a pressing device for squeezing. A cup is formed so that the surface covered with the film is the inner surface of the can, and then a re-drawing device is used to apply re-drawing and stretching to a smaller-diameter cup, followed by an ironing device. Is ironed to a thickness of about 0.12 mm, and the bottom is projected in a dome shape toward the inner surface of the can by a dormer to form a bottomed cylindrical can body.

The bottomed cylindrical can body thus formed is fed into an oven in an inverted state and heated to volatilize and remove the lubricant. At this time, it is preferable that the polyester resin layer is heated to a temperature equal to or higher than the melting point of the polyester resin coating the inner surface of the can and then rapidly cooled (air-cooled) to make the polyester resin layer amorphous.

Next, in order to adjust the length of the can body to a predetermined size, the opening side of the body is trimmed, and then the can body is passed through a hot-air heating furnace with a conveying screw to remove the can body from 130 to 130 mm.
After preheating to a temperature of 180 ° C., it is crowned on the mandrel of the film sticking device. When this mandrel passes through the induction heating device, the surface side is preheated to a temperature of 180 to 220 ° C., so that the canned body is heated to a temperature of 150 to 200 ° C. by the heat of the mandrel. Is done.

Next, the mandrel with the can body mounted thereon is moved to the sticking station of the film sticking apparatus, and the printed biaxially oriented polyethylene terephthalate film formed into the size of each can is adhered to the mandrel. In a state where the agent layer is on the outer side of the body of the can body, the adhesive is adhered by being gradually wound from the end of the printed resin film to the outer surface of the body of the can body by the pressing force of the application roll.

Then, the can body having the printed resin film adhered to the outer surface of the body is passed through an oven in an inverted state, and the can body is post-heat-treated at about 260 ° C. for about 60 seconds. After the printed resin film is completely heat-bonded to the outer surface of the body of the can body, it is immediately quenched to amorphize the polyester resin layer covering the inner surface side of the can body.

Example 2 In order to laminate a biaxially oriented film (protective film) of a polyester resin on one surface of an aluminum alloy strip (metal plate) for a drawn and ironed can, Although a biaxially oriented film of polyester resin is continuously applied to one surface of an aluminum alloy strip for a drawn and ironed can preheated to 260 ° C. while being pressed by an application roller, On the other hand, in Example 2, the adhesive strength between the polyester resin and the aluminum alloy plate was increased on one side of the aluminum alloy strip for a drawn and ironed can which had been heated to 260 ° C. in advance, and the inner side of the can was removed. In order to improve the corrosion resistance of, for example, an adhesive such as an epoxy-phenol adhesive,
A biaxially oriented film of polyester resin is adhered. Although this embodiment differs from the first embodiment only in this point, all other conditions are the same as those in the first embodiment.

With respect to the printed film sticking cans manufactured in each of the above embodiments, the outer surface of the body of ten cans was visually inspected in each embodiment. No shrinkage of the printed resin film was observed. In addition, for the printed film-sticking can body manufactured according to each of the above-described embodiments, a four-stage neck-in process is performed on the opening end side of the body portion for each of the embodiments, and then, a flange process is performed. After performing the above, the polymerized portion of the printed resin film stuck on the ten cans was visually inspected, but no peeling of the printed resin film was observed on any of the cans. Further, about 10 of these can bodies, the can bodies were cut open and the inner surface thereof was visually inspected, but no damage or peeling was observed on the polyester resin layer as the protective film on the inner surface side.

Comparative Examples In each of the above examples, a biaxially oriented film of a polyester resin was laminated on one side of an aluminum alloy strip, and an unsaturated polyester resin-based coating was formed on the other side. On the other hand, in this example, a polyester obtained by mixing the polybutylene terephthalate resin and the polyethylene terephthalate resin used in Example 1 on both surfaces of an aluminum alloy strip was used. A biaxially oriented resin film is laminated. Only in this regard, the first embodiment described above.
However, all other conditions are the same as in the first embodiment.

The outer surfaces of the body of 10 cans were visually inspected for the printed film-adhered cans manufactured according to the comparative examples described above, and shrinkage of the printed resin film was observed in all of them. Was done. (Specifically, the printed resin films on the opening end side and the bottom side of the can body shrunk by 2 to 3 mm in a direction away from each end side.)

According to the printed film-adhered can of the present embodiment as described above, the inner surface of the can is covered with a protective coating of a thermoplastic resin containing no bisphenol A (that is, the contents). The innermost layer in contact with the can is a thermoplastic resin layer containing no bisphenol A), so that bisphenol A does not elute in the contents filled in the can body, and the printed resin adhered thereto Since the protective coating on the outer surface of the can body, which is the lower layer of the film, is a non-thermoplastic curable resin coating, post-heating treatment is performed after the printed resin film is bonded to improve the bonding strength. Even if it is applied, the heat shrinkage of the printed resin film is not promoted as it is by the softening of the lower protective coating during the post-heating treatment, and the printed resin film shrinks by heat. The underlying protective coating does not like to expose widely.

As a result, by pre-printing the resin film to be adhered to the outer surface of the body of the can body, it is possible to perform overprinting using a gravure printing method or the like. Characters and designs to be applied to the outer surface can be provided as beautiful decorative prints that can also express subtle color changes, and the printed resin film on which such characters and designs are printed almost shrinks. In a state in which the can is not covered, a predetermined range on the outer surface of the body of the can is securely covered without widely exposing the lower protective coating, so that the appearance of the can is excellent. .

According to the manufacturing method of the present embodiment for manufacturing such a printed film-adhered can body, a protective coating of resin is laminated on both sides of a metal plate (one side is covered with heat). (A plastic resin layer is laminated and a curable resin layer is laminated on the other surface.) The can body is integrally formed from the coated metal plate, so that the high temperature applied to both sides of the coated metal plate in forming the can body Even when a relatively small amount of volatile lubricant is used, it can be thinned by forming a cup by punching and drawing, then drawing the cup and stretching it during ironing or drawing. The resin of the protective coating laminated on both sides of the metal plate also serves as a lubricant in forming into a can by processing, so that it is possible to avoid burning and scratching due to the generation of heat. Also, when removing the lubricant after molding, the lubricant is able to eliminate the most only volatile by heat treatment for a small amount, it is not necessary to use a large amount of washing water.

Further, since the printed resin film is bonded to the can body and then post-heated to a temperature higher than the activation temperature of the adhesive layer, the printed resin film and the outer surface of the body of the can body are in contact with each other. The adhesive strength of the resin film is improved, and there is no danger that the printed resin film will peel off from the can body in the subsequent neck / flange processing. Since it is a non-thermoplastic curable resin, the lower protective coating layer hardly softens during the post-heating treatment, so that the upper printed resin film is less likely to thermally contract (the printed resin film tends to thermally contract). The curable resin layer of the protective coating adhered to the printed resin film resists the force.) As a result, the printed resin film undergoes a large heat shrinkage due to post-heating treatment. Allowed is avoided that worsen the appearance of the can body.

Further, since the can body to which the molded and printed resin film is adhered is already coated on both the inner and outer surfaces of the can body with the protective coating of the resin, the inner and outer surfaces of the can body can be either. There is no need to spray a protective coating later on the part, and the manufactured printed film pasting can body is coated on its inner surface with a thermoplastic resin layer containing no bisphenol A. Therefore, there is no possibility that bisphenol A elutes in the contents during storage as a can.

The embodiments of the film-adhered can body and the method for producing the same according to the present invention have been described above.
It is not limited only to the above embodiments,
For example, for a printed resin film to be adhered to the body of a can, a top coat layer, a thermoplastic resin film layer, a printing ink layer, and an adhesive layer are sequentially formed as shown in FIG. Not only the printed resin film, but also a printed resin film in which a printing ink layer and a top coat layer are formed on one surface of the thermoplastic resin film layer and an adhesive layer is formed on the other surface Alternatively, it is also possible to use a printed resin film in which other layers such as a hologram forming layer and a metal deposition layer are appropriately formed.

In the above embodiment, the thermoplastic resin, which is the protective coating on the inner surface of the can, is made amorphous. For example, when the thermoplastic resin is laminated as a protective coating on a metal plate, it is difficult to form the protective coating. Using the axially oriented resin film and laminating so that the oriented crystal part remains, the heating temperature at the time of volatilizing the subsequent lubricant, at the time of attaching the printed resin film, and at the time of post-heating treatment, It can be changed as appropriate, such as leaving the oriented crystal part by setting the melting point to be lower than the melting point of the resin film (it is preferable for the contents requiring high corrosion resistance). Needless to say.

[0059]

According to the present invention as described above, according to the present invention, the protective film can be applied to the inner surface of the can without causing problems due to the dissolution of bisphenol A into the contents of the can. The can body can be formed without using a large amount of lubricant or washing water when the can body is formed from the metal plate. Can be activated to improve the adhesiveness between the printed resin film and the can body, and can effectively prevent the printed resin film from thermally shrinking during the post-heating treatment, Deterioration of the appearance of the can body due to shrinkage of the printed resin film can be avoided.

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view showing the appearance of (A) a state before a neck flange processing and (B) a state after a neck flange processing on a printed film sticking body.

FIG. 2 shows (A) a coated metal plate for manufacturing a can body, (B) a printed resin film, and (C) a printed film regarding the printed film-sticking can body according to one embodiment of the present invention. Sectional drawing which shows the laminated structure in the trunk | drum of a sticking can body, respectively.

FIG. 3 shows a conventional example of a printed film sticking can body.
(A) The side view of a can body which shows the state by which the printed resin film stuck was shrunk, and (B) The enlarged longitudinal cross-sectional view of the upper end part of a can body.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printed film sticking can body 1A Can body (can body except printed resin film) 2 Body 3 Bottom 4 Neck 5 Flange 11 Metal plate 12 Protective coating of thermoplastic resin 13 Protective coating of curable resin Reference Signs List 20 Printed resin film 21 Top coat layer 22 Thermoplastic resin film layer 23 Printing ink layer 24 Adhesive layer

Continued on the front page F-term (reference) 3E033 AA07 BA07 BA13 BA15 BA16 BA21 BB08 CA02 CA05 DA08 DD05 EA04 EA09 EA10 FA10 3E061 AA16 AC09 BA01 3E062 AA04 AB01 AB07 AC03 DA01 DA02 DA09 JA07 JA08 JB04 JC02 JD10 4F01 AB01 AK01 AB01 AK44 AK53 AL05 BA05 BA07 BA10A BA10E CA19 CB00D DA01 EC03 EH46 EH51 EJ19 EJ42 EJ50 GB16 HB31E JB13C JB16A JL04 JL11

Claims (2)

[Claims] 1. A printed film-attached can body, wherein a printed resin film is adhered via an adhesive layer to an outer surface of a body of a can body having a body and a bottom integrally formed, Is formed integrally from a coated metal plate in which a protective coating of a thermoplastic resin is formed on the inner surface of the metal plate and a protective coating of a curable resin is formed on the outer surface of the can. A printed film-adhered can body, characterized in that a printed resin film is adhered by thermal bonding via an adhesive layer on a curable resin protective film coated on its side. 2. A coated metal plate having one surface coated with a protective coating made of a thermoplastic resin and the other surface coated with a protective coating made of a curable resin. After applying the lubricant, the coated metal plate is first punched and drawn into a cup so that the surface coated with the thermoplastic resin is on the inner surface of the can and the surface coated with the curable resin is the outer surface of the can Then, after further forming the cup into a bottomed cylindrical can by re-drawing and body wall thinning, the can is heated and the applied lubricant is volatilized.
A printed resin film having an overcoat layer formed on the outer surface side and an adhesive layer formed on the inner surface side is adhered by pressing the adhesive layer of the resin film on the outer surface side of the body of the heated can body. After that, the can body to which the printed resin film is adhered is subjected to a post-heating treatment for heating the adhesive layer of the printed resin film to an activation temperature or higher. A method for producing a film-sticking can body.