JP2000185735A - Film-stuck can and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a resin film stuck on the surface of a can body with the aid of an adhesive layer from being released therefrom even when a can is subjected to retort treatment after an opening portion of the can body is diametrally narrowed in a precise manner in case of the necking-in of such a film-stuck can made of a metal, whose can body and can bottom are integrally formed, as to have a printed resin film stuck on the outer surface of the can body. SOLUTION: In such a film-stuck can made of a metal, whose can body and can bottom are integrally formed, as to have a printed resin film stuck on the outer surface of the can body, an organic/inorganic composite formation processing film which has 1 to 7 mg/m2 as an adhesion amount of phosphorus (P) and 5 to 50 mg/m2 as an amount of film carbon (C) and in which the ratio (C/P) of the amount of film carbon to the adhesion amount of the phosphorus is 2 to 10, is formed in advance on a metallic surface of the can, on which a resin film is stuck. A diameter of an opening portion at the top end of the can body is diametrally narrowed so as to be in the range of 79-87% with respect to the diameter of the can body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film sticking method in which a printed resin film is stuck to the outer surface of a metal can body in which a can body and a can bottom are integrally formed. More particularly, the present invention relates to a film-adhered can body in which a top end opening of a can body to which a printed resin film is adhered is neck-in processed so as to be greatly reduced in diameter, and a method of manufacturing the same.

[0002]

2. Description of the Related Art When a desired character or pattern is to be provided to a can body of a can container, a plate-shaped metal plate is rolled and both ends thereof are joined by electric resistance welding or an adhesive. In a three-piece can in which a can lid (canopy) and a can bottom (ground lid) are tightly wound, characters and patterns are printed in advance on a plate-shaped metal plate serving as a blank for a can body. For two-piece cans, in which the can body and can bottom (ground lid) are integrally formed by deep drawing or drawing and ironing from a plate, printing of characters and patterns on the cylindrical can body is performed. Become.

[0003] Therefore, in a three-piece can that prints characters and patterns on a plate-shaped metal plate, overprinting by offset printing and other printing methods can be appropriately and selectively performed. In the case of a two-piece can that prints characters and patterns on a cylindrical can body, it is practically difficult to directly apply overprinting by offset printing. Is used to print characters and designs.

However, in dry offset printing on two-piece cans, inks of all colors are applied using a common blanket, and inks of each color are applied so that they do not overlap. Therefore, the number of colors and the color tone are limited. Because
It is difficult to respond to a case where a more beautiful appearance is required due to diversification of products due to changes in consumption trends and needs.

In order to cope with such a demand, instead of printing directly on the surface of the can body, characters or patterns are printed in advance on a film of a thermoplastic resin such as polyester, and this printing is performed. Various proposals have been made to attach desired characters and designs to the can body by attaching the finished resin film to the can body via the adhesive layer. (For example, see JP-A-3-230
940, JP-A-4-57747, JP-A-7
(See -89552)

[0006] According to such a film-adhered can body, gravure printing and other printing methods other than offset printing can be appropriately selectively performed on a thermoplastic resin film serving as a main layer. Therefore, for example, by printing characters and designs by gravure printing, compared to the case of dry offset printing, the number of colors and the degree of freedom of the color tone can be increased, and more beautiful printing can be performed. It is possible to print many cans continuously on a long thermoplastic resin film instead of printing individually on each can. Can be expected.

On the other hand, when manufacturing cans, in order to reduce the total cost required for cans, the thickness of the metal plate to be used is reduced and the easy-open can lid (easy open end) which becomes a can lid (top lid) is used. Conventionally, reducing the diameter of EOE) has been promoted. For easy opening can lids, for example, in the case of a 350 ml beer can, a so-called 211 can be used.
In a can body having an inner diameter of about 65.8 mm (outer diameter of a can lid winding portion is 2 + 11/16 inches), the can lid to be wound is usually for 211, but the opening of the dry offset printing can body is called Is currently 206 (about 57.4m
m, the outer diameter of the can lid winding part is 2 + 6/16 inch).
In part, 204 (approximately 54.9 mm, outer diameter of the can
+4/16 inch), and 2
02 (approximately 52.3 mm, outer diameter of the can lid winding part is 2 + 2/16
Inches).

[0008]

However, in order to reduce the diameter of the can lid in the above-mentioned can container, the opening of the upper end of the can body must be made closer to the can body (can container body). It is necessary to reduce the diameter to a small diameter (diameter reduction), and by such reduction in diameter of the can body, not only the metal forming the body of the can body but also the organic resin layer covering the surface of the can body Will be subjected to severe processing.

Particularly, in the case of a film-attached can body in which a printed resin film is adhered to a can body, a metal body for a two-piece can having a can body and a can bottom integrally formed by drawing or drawing and ironing. In the conventional chemical conversion treatment of metal surfaces with chemicals mainly composed of zirconium phosphate in can bodies, the adhesion between the resin film and the surface of the can body when the diameter of the upper end of the can body is reduced When the retort treatment is performed after performing severe diameter reduction during neck-in processing, there is a case where the resin film may peel off from the surface of the can body. Further, there is a need for further improving the adhesion of the resin film to the surface of the can body.

An object of the present invention is to solve the above-mentioned problems. More specifically, the present invention relates to a metal can body in which a can body and a can bottom are integrally formed. Even when a resin-adhered can body with a printed resin film attached to it is subjected to severe diameter reduction during neck-in processing and then subjected to retort treatment, it is adhered via an adhesive layer. It is an object of the present invention to prevent the applied resin film from peeling off from the surface of the can body.

[0011]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a resin having at least a top coat layer, a printing ink layer and an adhesive layer formed on a main layer of a thermoplastic resin film. A film-adhered can body in which a film is adhered to the outer surface of a metal can body in which a can body and a can bottom are integrally formed via an adhesive layer of the resin film. The amount of phosphorus (P) attached to the metal surface of the can body to which the resin film is adhered is 1 to 7 mg /
m ² , the film carbon (C) amount is 5 to 50 mg / m ² , and the ratio (C / P) of the film carbon amount to the phosphorus adhesion amount is 2 to 10 mg / m ² .
While forming an organic-inorganic composite chemical conversion coating film, the diameter of the opening at the upper end of the can body is 79-79 with respect to the diameter of the can body.
The diameter is reduced so as to fall within the range of 87%.

Further, in the method of manufacturing a film-attached can body having such a structure, when the resin film is attached to the outer surface of the can body of the metal can via the adhesive layer,
In a state where the can is heated to 130 to 220 ° C., a resin film is thermally bonded to the outer surface of the cylindrical can body of the can.

According to the film-adhered can body having the above structure, the specific organic-inorganic composite chemical conversion treatment film defined as described above is formed on the metal surface of the can body, so The adhesion of the resin film adhered to the surface of the can body via the agent layer with the can body surface is improved. In particular, the diameter of the opening at the upper end of the can body is 79 to the diameter of the can body. ~ 8
Even when the diameter is reduced at a high diameter reduction ratio so as to be in the range of 7%, the resin film does not peel off from the surface of the can body after the retort treatment.

Further, according to the method for manufacturing a film-attached can body as described above, the film-adhered can body having the above-described structure can be used to improve the adhesion between the resin film and the surface of the can body using an adhesive. , And with excellent appearance without protruding the adhesive.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of a film sticking can according to the present invention will be described in detail.

The film-attached can body of the present embodiment is a metal can body for a two-piece can in which a can body and a can bottom (ground lid) are integrally formed by deep drawing or drawing and ironing.
A printed resin film composed of a top coat layer / a thermoplastic resin film layer / a printing ink layer / an adhesive layer is adhered to the outer surface side of the can body via the adhesive layer by thermal bonding.

In such a film-attached can body, the metal surface of the can body to which the printed resin film is adhered is
From 1 to 7 mg / m ² as phosphorus (P) adhering amount, 5 to 50 mg / m ² as a film of carbon (C) content, and the ratio of the coating amount of carbon and phosphorus deposition amount (C / P) is 2-10 An organic-inorganic composite chemical conversion treatment film is formed by chemical conversion treatment,
A printed resin film is adhered to the outer surface of the can body via the adhesive layer from above the organic-inorganic composite chemical conversion treatment film.

The can body to which the printed resin film is adhered is reduced by neck-in processing so that the diameter of the opening at the upper end is in the range of 79 to 87% of the diameter of the can body. The opening at the upper end of the can body, which has been reduced in diameter and has been subjected to the flange processing together with the neck-in processing, is closed by tightening the easy-open can lid (top lid) after filling the contents.

The details of the film-sticking can body of the present embodiment as described above will be described below. First, a metal can body for a two-piece can is drawn from a steel or aluminum alloy metal disk by drawing and ironing. In the case of a DI can (draw / ironing can) in which a can-shaped can body and a can bottom (ground lid) are integrally formed, the plate thickness is 0.20 mm to 0.2 mm.
Tin adhesion per side of 30 mm thin steel plate is 1.
A steel can made from a tin-plated steel sheet having a thickness of 0 to 6.0 g / m ² , or a sheet thickness of 0.20 mm to 0.32 m
An aluminum can made of a 3004 series aluminum alloy is used.

The thickness of the DI can material as described above is mainly determined by the strength of the can, especially the pressure resistance of the bottom of the can (commonly called bottom pressure), and the thickness is selected by the internal pressure after filling the contents. In the case of internal pressure cans (cans with high internal pressure) for filling and sealing carbonated beverages or beer, the thickness is 0.20 m
m or less, the so-called buckling may cause the bottom of the can to protrude, which is not preferable. However, a steel material having a thickness of 0.30 mm or more, and an aluminum material having a thickness of 0.32 mm or more, has a pressure resistance of Well secured, but substantially over-quality and not economical.

It is to be noted that the phenomenon such as the buckling is determined depending on the mechanical strength of the metal material even if the thickness is the same, and when the mechanical strength is high irrespective of the steel material or the aluminum material. Since the sheet thickness can be reduced, it is desirable to appropriately select the sheet thickness of the metal material in consideration of the strength balance of the entire can.

In the present embodiment, the printed resin film adhered to the outer surface of the can body of the metal can body is, in the present embodiment, a printed film composed of a top coat layer / a thermoplastic resin film layer / an ink layer / an adhesive layer. A resin film is used.

The thermoplastic resin film serving as the main layer of the printed resin film plays a role as a holding portion of the printing ink layer, and the clarity and gloss of the printed finish appearance of characters and patterns to be printed are provided. Since it is necessary to ensure softness, it is basically necessary to use a transparent or translucent material. After filling the contents, sterilization treatment is carried out at 125 ° C. for 30 minutes in the strictest case as a sterilization treatment. Is required to have a heat resistance of at least 130 ° C. or more to withstand this treatment.

For such a reason, a polypropylene resin film, a polyamide (nylon) resin film, a polyester resin film or the like is used as the thermoplastic resin film. The biaxially stretched film oriented and crystallized is most suitable.

Examples of the polyester resin film include homopolymers such as polyethylene terephthalate (PET), polyethylene isophthalate (PEI) and polybutylene terephthalate (PBT), copolymer resins of polyethylene terephthalate and polyethylene isophthalate, and polybutylene terephthalate and polybutylene terephthalate. Various polyester resin films such as copolymer resins such as butylene isophthalate copolymer resin, blend resins of polyethylene terephthalate and polyethylene isophthalate, and blend resins of polyethylene terephthalate and polybutylene terephthalate can be used.

The thickness of the thermoplastic resin film is preferably 8 to 20 μm (preferably 10 to 18 μm) for the following reasons.

That is, the printed resin film is adhered so as to go around the cylindrical can body.
Depending on the printed characters and patterns, the film may be attached to the can body as a longer film than the circumferential length of the can body. In such a case, the overlapping portion (lap portion) between both ends of the film is inevitable. Is generated, and the side of the overlapping portion is apt to become a gap. The gap tends to occur as the film thickness increases, and tends to be large.

Therefore, when the thickness of the thermoplastic resin film as the main layer of the printed resin film is 20 μm or more, the film peeling from the above-mentioned void portion (delamining).
However, since it is easy to occur particularly at the time of the retort treatment, which is not preferable, a thinner film is more advantageous in order to prevent the peeling of the film from such a void.

On the other hand, when producing a film-attached can body,
In order to attach the printed resin film to each can, a long film with a continuous printing of multiple cans is cut into film sheets for each can. In order to accurately cut the film into the size of each can, the resin film itself must have a certain strength or more, which requires a certain thickness, and the thermoplastic resin film that will be the main layer If the thickness is 8 μm or less, it becomes difficult to cut the size of each can at high speed with high accuracy.

Regarding the top coat layer formed on the surface side of the printed resin film, the resin film is prevented from being damaged due to insufficient slipperiness of the can body, and the physical change of the resin film at the time of retorting, that is, , Provided to prevent changes in crystallinity and optical properties due to water content,
Since all of them are intended to ensure the appearance of the finished print, they need to be a colorless and transparent film layer having good slipperiness and retort resistance.

As such a top coat layer, a thermosetting paint, an electron beam curable paint, an ultraviolet curable paint, or the like is used. Further, in order to further improve the slipperiness, a lubricating material such as silicon or wax is used. An agent may be added.

As the thermosetting paint, a so-called clear paint such as an epoxy-amino resin, an epoxy-melamine resin, or a polyester-amino resin is used. As the electron beam-curable paint, an epoxy acrylate resin or a polyester acrylate resin is used. , Polyurethane acrylate resins, polyether acrylate resins, etc., and these resins may be used alone or as a mixture of two or more.

As the UV-curable paint, the resin raised as the above-mentioned electron beam-curable paint may be added to a monofunctional monomer such as 2-hydroxyethyl acrylate or tetrahydrofurfuryl acrylate, or dicyclobenthenyl acrylate. One or two types of a bifunctional monomer such as 4-butanediol acrylate or a trifunctional monomer such as trimethylolpropane triacrylate as a photopolymerization diluent.
A mixture of more than one kind, and further a paint such as acetophenone, benzophenone or the like as a photopolymerization initiator may be used.

With respect to the slipperiness of the top coat layer, the coefficient of static friction is preferably 0.2 or less, and a coating layer having such a coefficient of friction is preferred. Of course, as the top coat layer, the thermosetting paint, the electron beam-curable paint,
It is also possible to apply UV-curable paint alone,
It is also possible to use two or more kinds in combination, and a method suitable for the equipment may be appropriately employed.

When a thermosetting paint is used as the top coat layer, heat is naturally applied, and the heating conditions, particularly the temperature, are adjusted in consideration of the thermal influence of the thermoplastic resin film as the main layer. Needless to say, it is necessary to select a paint that cures at or below the melting point of an electron beam-curable paint or an ultraviolet-curable paint that does not require heat, or a combination of these paints and a thermosetting paint. preferable.

The thickness of the top coat layer is 1 to 4
μm is optimal from the viewpoint of ensuring slipperiness and retort resistance, and below 1 μm, the uniformity of the coating film is insufficient.
It is not preferable because neither the slip property nor the retort treatment property is secured. On the other hand, when the thickness is 4 μm or more, the uniformity of the coating film is sufficient, and both the slipperiness and the retort treatment resistance are ensured, but the effect is saturated and is not economical.

When a lubricant such as silicon or wax is added to the top coat layer for the purpose of improving the slipperiness, if the thickness is 4 μm or more, if the amount of silicon or wax added is large, the top coat layer is not removed. It is not preferable because irregular reflection of light occurs in the coat layer, which causes a reduction in the sharpness of the design.

The printing ink layer formed on the back side of the thermoplastic resin film is not particularly limited since characters and patterns are applied by printing, but a thermosetting urethane resin is used as a binder. It uses ink, and as its printing method, various printing methods such as gravure printing, flexographic printing, offset printing, etc. can be selected as appropriate, but rich colors and beautiful characters using a large number of colors When it is desired to print patterns or designs, it is preferable to form a printing ink layer by gravure printing.

The adhesive layer provided so as to cover the printing ink layer is basically made of an adhesive which can be easily bonded to the outer surface of the metal can by applying pressure and heat. As the adhesive, a thermosetting adhesive, an electron beam curing adhesive, a combined thermosetting and electron beam curing adhesive, or the like is used.

As the thermosetting adhesive, epoxy resin,
Resin such as polyester resin, copolymer resin of epoxy and polyester as main agent, melamine resin as curing agent,
An adhesive of a resin composition containing a curing agent such as an isocyanate resin is used, and as an electron beam-curable adhesive, a polyester resin or an epoxy resin as a main component, and an ester to which an unsaturated double bond is added as an electron beam sensitive resin. An adhesive of a resin composition obtained by adding a stress relaxation agent to a resin composition containing an oligomer, if necessary, is used.

In addition, as the adhesive of the combined use of heat curing and electron beam curing, a resin composition containing a polyester resin as a main component and an ester oligomer having an unsaturated double bond added as an electron beam sensitive resin may be used, if necessary. Then, an adhesive of a resin composition comprising a curing agent such as a melamine resin and an isocyanate resin is used as a thermosetting agent.

The adhesive forming the adhesive layer is not limited to the above-described adhesive composed of only the resin composition,
An adhesive obtained by further adding a white pigment to such a resin composition is also used. When a white pigment is added, an inorganic pigment such as titanium oxide or mica is used in an amount of 20 to 80 parts by weight based on 100 parts by weight of the resin composition. Parts.

If the amount of the white pigment is less than 20 parts by weight with respect to 100 parts by weight of the resin composition, the concealing ratio is insufficient, and the influence of the spectral reflectance of the underlying metal appears. In some cases, the print appearance becomes bluish tones, and the gloss and clarity of the trademark may be impaired. On the other hand, even if the white pigment is contained in an amount exceeding 80 parts by weight, the concealing rate does not increase and the effect is saturated, so that not only is it not economical, but also the cohesive force of the adhesive itself is reduced, and the result is that the adhesion is rather poor. Become.

In particular, in order to reduce the diameter of the upper end of the can body during neck-in processing, if the content of the white pigment is too high,
Because the cohesive failure of the adhesive itself causes peeling of the printed resin film, the content of the white pigment must be selected from the balance between whiteness and adhesion,
The above-mentioned concealing property is related to the thickness of the adhesive to be applied, that is, the amount to be described later, so that in order to obtain an adhesive having both whiteness and adhesion, the white pigment is based on 100 parts by weight of the resin composition. , 30 to 70 parts by weight.

Regarding the amount of the adhesive applied to form the adhesive layer, the appropriate amount of the adhesive differs between an adhesive composed of only the resin composition and an adhesive obtained by adding a white pigment to the resin composition. , regardless of the three types of the adhesive, the former is in the range of 10 to 50 mg / dm ^2, in the latter case is in the range of 40~170mg / dm ^2.

That is, the adhesive force to be provided as the adhesive layer naturally depends on the resin composition. However, in the present embodiment, the adhesive layer is formed so as to cover the printing ink layer. If it is less than 10 mg / dm ² , it is difficult to apply the adhesive uniformly, and depending on the type of ink, a part of the adhesive may be absorbed by the printing ink layer, and may not be applied or applied locally. The same phenomenon as in the case of a portion may occur, and so-called delamination in which the printed resin film is locally peeled off may occur. On the other hand, 50m
When the value exceeds g / dm ² , the same phenomenon as in the above-described uncoated or uncoated portion does not occur locally, but the internal stress due to the curing of the adhesive increases, and the resin cannot withstand neck-in processing. It is not preferable because it may be peeled off.

In the case of an adhesive containing a white pigment,
Is 40 mg / dm^Two If less, the adhesion will be ensured but hidden
Whiteness is not secured due to insufficient opacity. On the other hand, 170 mg
/ Dm ^Two Even if it exceeds, the whiteness is saturated and the amount of adhesion is increased
The effect is not economical and cannot be expected.

By the way, the above-mentioned printed resin film (a resin film composed of a top coat layer / a thermoplastic resin film layer / an ink layer / an adhesive layer) is adhered to the outer surface of the can body with good adhesion ( In this embodiment, an organic-inorganic composite chemical conversion coating of phosphoric acid or zirconium phosphate and an organic resin is applied to at least the metal surface of the metal can body (steel can or aluminum can) for lamination. Is formed as a surface treatment film.

The organic-inorganic composite chemical conversion coating film is formed not only on the outer surface side of the can body but also on the inner surface side of the can body, so that the inner surface of the can body is secured for the purpose of ensuring the corrosion resistance of the can body. Good characteristics can be imparted to the coating film adhesion of the applied coating, which does not peel off by neck-in processing with a high diameter reduction rate.

This organic-inorganic composite chemical conversion coating film has a coating amount of phosphorus (P) of 1 to 7 mg / m ² and a coating carbon (C)
The amount is 5 to 50 mg / m ² , and the ratio (C / P) between the amount of carbon film and the amount of attached phosphorus is in the range of 2 to 10.

The film-adhered can body of this embodiment, in which a printed resin film is adhered (laminated) on the outer surface side of the can body via such an organic-inorganic composite chemical conversion treatment film, has an opening at the upper end of the can body. The diameter of the part is reduced by 79-87% from the diameter of a normal can body by neck-in processing, so that it is formed as a so-called reduced diameter can.

In the film-adhered can body of the present embodiment as described above, the amount of phosphorus (P), the amount of carbon (C), and the amount of carbon (C) of the organic-inorganic composite chemical conversion coating formed as a surface treatment coating on the metal surface. Ratio of film carbon amount to phosphorus adhesion amount (C / P)
The meaning of the fact that the diameter of the opening at the upper end of the can body is reduced to 79 to 87% of the diameter of the can body will be described below.

The composite chemical conversion treatment for forming an organic-inorganic composite chemical conversion coating on the metal surface of the can body is a reaction type treatment in which the metal body is dissolved and deposited, and the polymerization reaction of the organic resin is performed by heating and drying after the treatment. Occurs and a polymer film is formed.The organic resin is relatively abundant in the surface layer of the treated film, and the adhesive force with the adhesive or paint is strong. The organic-inorganic composite chemical conversion treatment film works more effectively as the neck-in processing with a high diameter reduction rate is performed.

In order for this organic-inorganic composite chemical conversion coating to work effectively, the amount of phosphorus (P) deposited is 1 to 7 mg / m ² , and the coating carbon (C) is used for the following reasons.
It is necessary that the amount is 5 to 50 mg / m ² and that the ratio (C / P) between the amount of phosphorus attached and the amount of carbon in the coating is in the range of 2 to 10. , Film carbon (C) amount, and the ratio of film carbon amount to phosphorus adhesion amount (C /
With respect to the organic-inorganic composite chemical conversion treatment film in which the range of P) is limited, in particular, the designation 211 (canister inner diameter is about 65.8 mm)
No. 204 (opening inner diameter of about 5)
4.9mm) and name 202 (opening inside diameter about 52.3m)
m), which is effective when neck-in processing with a high diameter reduction ratio is performed.

First, regarding the amount of phosphorus (P) deposited, phosphorus (P) is present in the film as a phosphorus compound, and the bonding of the organic resin during heating and drying is strengthened, and the entire film is tough. It is estimated that. The amount of P attached is the lower limit of 1 mg / m
^If it is less than ² , the bonding strength of the obtained film is inferior, and the printed resin film adhered thereon with an adhesive layer is peeled off when the upper end opening of the can body is reduced in diameter by neck-in processing (commonly known as (Called "delami"), which is not preferable.

On the other hand, even if the amount of P adhered exceeds the upper limit of 7 mg / m ² , the printed resin film adhered thereon with the adhesive layer may be peeled off by neck-in processing. This is presumed to be due to the distortion at the time of deposition of the coating. If the upper limit of 7 mg / m ² is exceeded, the coating itself cannot withstand neck-in processing and the coating itself is cohesively broken. From this, the P adhesion amount is 1 to 7 mg / m ² (preferably 1. mg / m ² ).
5-6 mg / m ² ).

Next, regarding the amount of carbon (C) in the film, the amount of the film C is measured as a conversion amount of the amount of the organic resin adhered. When the amount of the film C is 5 mg / m ² or less, which is the lower limit, Insufficient adhesion due to poor coverage of the conversion coating on aluminum and steel cans, and local release of the resinous film during neck-in and flange processing after attaching the printed resinous film Even when the resin film is not conspicuous in the neck-in processing or the flange processing, the retort treatment performed after the filling of the contents may cause clear film peeling.

On the other hand, when the amount of the film C is the upper limit of 50 mg / m ^2.
When the diameter exceeds 200, the coatability is good, but the degree of neck-in processing is large (for example, the diameter of the can body of the designation 211 is reduced and the diameter of the opening is designated as the designation 204 or 202). In the processing, as described above for the reason for limiting the amount of P attached, the coating itself may cause cohesive failure and the adhesion may be reduced, whereby the resin film may be peeled off. Therefore, (preferably 10 to 40 mg / m ²⁾ the coating amount of C 5 to 50 mg / m ² is limited in the range of.

Further, the organic-inorganic composite chemical conversion coating film has characteristics such as ensuring adhesion to the adhesive or paint of the organic resin and ensuring the toughness of the entire film by polymerizing the organic resin. The processing adhesion of the coating is affected by the ratio (C / P) of the coating C amount to the P adhesion amount. Therefore, the ratio (C /
P) is limited to the range of 2 to 10 (preferably 3 to 8).

That is, the ratio (C /
When P) is less than 2, the properties of the organic resin, such as adhesion to the adhesive or paint, are not sufficiently exhibited, and the adhered resin film may be peeled off due to neck-in processing for reducing the diameter. And when (C / P) exceeds 10,
When the bonding strength of the film is insufficient and the toughness of the entire film is inferior, the adhered resin film may be peeled off by the neck-in processing for reducing the diameter.

For the above-mentioned organic-inorganic composite chemical conversion coating film, for example, a chemical conversion of zirconium phosphate alone applied to a can body obtained from aluminum drawing and ironing which is currently performed in many cases. Even for the treated film, the diameter reduction rate of neck-in processing [(can body diameter-can body opening end inside diameter)
/ (Can inner diameter) is less than 13%, the adhesion is ensured.

However, when the degree of neck-in processing is increased and the diameter reduction ratio becomes 13% or more, the printed resin film adhered to the can body may be peeled off by retort treatment. When the diameter ratio is about 16%, the probability that the printed resin film is peeled off by the retort treatment is further increased, and the film cannot be used with security.

On the other hand, in the case of the above-mentioned organic-inorganic composite chemical conversion coating film of the present embodiment, a good reduction in the diameter is achieved by exhibiting good adhesion and reducing the diameter of the neck-in process to 13% or more. Even if the processing is performed, the printed resin film works effectively without being separated by the retort treatment. This has been confirmed from the results (Tables 1 to 4) of the respective experimental examples described below.

The effects of the film-sticking can of the present embodiment as described above were confirmed by the following experimental examples. In addition, the evaluation method performed in each experimental example is as follows. (1) The amount of C in the organic-inorganic composite chemical conversion coating is the total organic carbon content (TOC-5000 / SSM-5000A) manufactured by Shimadzu Corporation.
(Solid sample TOC measurement system). (2) The amount of P adhered to the organic-inorganic composite chemical conversion treatment film
It was measured by a line analysis (X-Ray Spectrometer / Rigaku Denki Kogyo). (3) The state of protrusion of the adhesive in the multilayer organic film laminated can was evaluated by visual observation and observation with an optical microscope. The evaluation of the state of protrusion of the adhesive was performed by setting evaluation criteria as follows. 〇: Good without sticking out of adhesive □: Slightly sticking out (practical) △: Sticking out visible to the naked eye (not practical)
×: Many protrusions (impractical) (4) Regarding the state of the printed resin film in the neck-in processing and the flange processing, the peeling state and the crack generation state were evaluated by visual observation and optical microscope observation. The evaluation of the peeling state and the crack generation state was performed by setting evaluation criteria as follows. 〇: Good without peeling or cracking □: Minor cracking (practical) △: Partial peeling or cracking (not practical) ×: Peeling (not practical)

Experimental Example 1 An aluminum plate (3004 alloy) having a thickness of 0.28 mm was drawn and ironed by a known method, and the opening was trimmed.
After preparing a two-piece can for a 350 ml beer can, degreasing is performed by a well-known method, and immediately using a chemical solution containing phosphoric acid and a water-soluble phenol resin as main components by spraying, the amount of the film C, the amount of P attached and the ratio ( (C / P) was changed, and the product was washed with water and dried with hot air. The can thus obtained is coated with a thermosetting adhesive layer (containing a white pigment) having a coating amount of 130 mg / m ² , a printing ink layer, a biaxially oriented polyester resin film layer having a thickness of 12 μm, and a resin having a top coating layer having a thickness of 2 μm. The can was heated by high-frequency induction heating so that the adhesive layer was in contact with the outer surface of the can, the can body temperature was 165 ° C., the linear pressure was 35 kgf / cm, and the speed was 175.
It was stuck (laminated) under the condition of m / min. Thereafter, the inner surface of the can body is spray-coated, dried at 200 ° C. for 60 seconds, and then subjected to multi-stage neck-in processing to make the opening (opening end) a can diameter designation 206 and a can diameter designation 202 to form a reduced diameter can. After the retort treatment was performed at 125 ° C. for 30 minutes, the peeling state of the resin film at the neck processed portion was examined. The results are shown in Table 1 below.

[0066]

[Table 1]

From Table 1 above, it can be seen that Test Nos. 2 to 6
It can be seen that (Examples of the present invention) had better adhesion than Test Nos. 1 and 7 (Comparative Examples). In particular, it can be seen that this is effective for a diameter reduction process such as a neck-in process of forming the opening diameter of the can body of the designation 211 to the designation 202. In addition, the protrusion of the adhesive was not seen in all the chemical conversion treatment samples, and was good.

[Experimental Example 2] A tin-coated steel sheet having a sheet thickness of 0.24 mm and having a tin adhesion of 2.8 g / m ^{2 on} both sides was drawn and ironed by a known method, and the opening was trimmed. After preparing a two-piece can for a 350 ml beer can with a nominal diameter of 211, degreasing is performed by a well-known method, and immediately using a chemical solution containing phosphoric acid and a water-soluble phenol resin as main components, the amount of the film C and the amount of P deposited by a spray method. And a chemical conversion treatment in which the ratio (C / P) was changed, washed with water and dried with hot air. With respect to the can thus obtained, a thermosetting adhesive layer (containing a white pigment) having a coating amount of 130 mg / m ² , a printing ink layer, and a thickness of 12 μm
a biaxially stretched polyester resin film layer having a thickness of 2 m and a top coat layer having a thickness of 2 μm, and heating the can body by high frequency induction heating so that the adhesive layer is in contact with the outer surface of the can body. Body temperature 165 ° C, linear pressure 35kgf / c
m and a speed of 175 m / min. Thereafter, the inner surface of the can body is further spray-painted,
After drying at 0 ° C. for 60 seconds, the opening is subjected to multi-stage neck-in processing to make a can diameter designation 206 and a can diameter designation 202, respectively, to reduce the diameter of the can, and then a retort treatment is performed at 125 ° C. for 30 minutes. The state of peeling of the resin film at the neck processing portion was examined. The results are shown in Table 2 below.

[0069]

[Table 2]

Referring to Table 2 above, Test Nos. 9 to 12
It can be seen that (Each Example of the present invention) has better adhesion than Test Nos. 8 and 13 (Comparative Example). In addition, the protrusion of the adhesive was not seen in all the chemical conversion treatment samples, and was good.

[Experimental Example 3] An aluminum plate (3004 alloy) having a thickness of 0.28 mm was drawn and ironed by a known method, and the opening was trimmed.
After preparing a two-piece can for a 350 ml beer can, degreasing is performed by a well-known method, and immediately using a chemical solution containing phosphoric acid and a water-soluble phenol resin as main components by spraying, the amount of the film C, the amount of P attached and the ratio ( (C / P) was changed, and the product was washed with water and dried with hot air. The can thus obtained is coated with a thermosetting adhesive layer (containing a white pigment) having a coating amount of 130 mg / m ² , a printing ink layer, a biaxially oriented polyester resin film layer having a thickness of 12 μm, and a resin having a top coating layer having a thickness of 2 μm. The can was heated by high-frequency induction heating so that the adhesive layer was in contact with the outer surface of the can, the can body temperature was 165 ° C., the linear pressure was 35 kgf / cm, and the speed was 175.
It was stuck (laminated) under the condition of m / min. Thereafter, the inner surface of the can was spray-coated, dried at 200 ° C. for 60 seconds, and subjected to multi-stage neck-in processing to make the opening into a can diameter designation 206 and a can diameter designation 202, respectively, to obtain reduced diameter cans. After performing the retort treatment at 125 ° C. for 30 minutes, the state of peeling of the resinous film at the neck processed portion was examined. The results are shown in Table 3 below.

[0072]

[Table 3]

Referring to Table 3 above, test Nos. 15-1
8 (each Example of the present invention) has better adhesion than Test Nos. 14 and 19 (comparative examples). In addition, the protrusion of the adhesive was not seen in all the chemical conversion treatment samples, and was good.

[Comparative Example] An aluminum plate (3004 alloy) having a plate thickness of 0.28 mm was drawn and ironed by a known method, the opening was trimmed, and a two-piece for a 350 ml beer can having a can body diameter of 211 was designated. After the can was prepared, degreasing was performed by a well-known method, and a chemical conversion treatment was immediately performed using a commonly used chemical solution containing zirconium phosphate containing no organic resin by a spray method, followed by washing with water and hot-air drying.
The Zr content of the chemical conversion coating on the obtained can was 15 mg /
m ² . (The C content in the film is 0 mg / m ^2. ) With respect to the can thus obtained, the resin film used in Experimental Example 1 was placed so that the adhesive layer was in contact with the outer surface of the can. Then, the can body is heated by high frequency induction heating, and the can body temperature is set to 1
It was pasted (laminated) under the conditions of 65 ° C., a linear pressure of 35 kgf / cm, and a speed of 175 m / min. Thereafter, the inner surface of the can was spray-coated, dried at 200 ° C. for 60 seconds, and subjected to multi-stage neck-in processing to make the opening into a can diameter designation 206 and a can diameter designation 202, respectively, to obtain reduced diameter cans. After performing the retort treatment at 125 ° C. for 30 minutes, the state of peeling of the resinous film at the neck processed portion was examined. As a result, the evaluation of the peeling state in the neck processed portion reduced in diameter to the can diameter designation 206 is 〜 to □, which is good as in each example of the present invention and has practicality in terms of adhesion. , Can diameter designation 202
The evaluation of the peeling state in the neck processing part with a reduced diameter is as follows.
×, the results were inferior to the examples of the present invention.

An example of a method of manufacturing the film-adhered can body of the present embodiment, the effect of which has been confirmed by each of the experimental examples described above, will be described below.

As for the can before the printed resin film is attached, the metal plate is subjected to deep drawing or drawing and ironing to form a bottomed cylindrical metal can for a two-piece can. The upper end opening of the cylindrical can body is cut and trimmed so as to have a predetermined can height, and the metal can body after trimming is degreased, and then an organic-inorganic composite chemical conversion treatment is performed as a surface treatment of the metal surface. It should be noted that the can body manufacturing technology before performing the organic-inorganic composite chemical conversion treatment is based on a well-known technology currently used by can manufacturers and is not particularly limited.

The organic-inorganic composite chemical conversion treatment performed after the metal can is degreased includes phosphoric acid or phosphoric acid, zirconium fluoride, and a water-soluble organic resin (eg, a water-soluble phenol resin, a water-soluble acrylic resin, etc.). Spraying the treatment solution with hydrofluoric acid and polyphosphoric acid added to the aqueous solution as necessary to promote the reactivity, and spray-coating on the can body in the same manner as the conventional chemical treatment method, then washing with water and drying to cure After the can body is immersed in the treatment liquid, it is washed with water, dried and cured. Also, as a drying and curing method,
Conventional methods such as drying with hot air and drying in an electric furnace can be applied. The temperature is 150 ° C. to 250 ° C., and the drying time is 10 seconds to 2 seconds.
Minutes.

On the other hand, in the production of a printed resin film, first, a top coat is applied to one side of a thermoplastic resin film to be a main layer and dried to form a top coat layer. On the opposite surface, an ink is printed and dried to form a printing ink layer, and then an adhesive is applied so as to cover the printing ink layer and dried to form an adhesive layer.

It is preferable that the printing ink layer is sufficiently dried. However, the adhesive layer becomes the surface to be adhered to the outer surface side of the metal can body later. In the case of a combined use of a mold adhesive and an electron beam-curable adhesive, it is important to make the semi-dry state without curing.

For the coating of the top coat and the adhesive,
Gravure coating or flat roll coating may be used, but the application method may be changed between the top coat layer and the adhesive layer. That is, if the printed resin film attached to the can body is attached slightly longer than the circumferential length of the can body so that the characters and designs of the printed resin film are not cut in the middle of the can body, the resin film A lap portion will be formed so that both end portions of the will slightly overlap, in which case the adhesive is applied to the entire surface,
The top coat needs to be applied short so as not to be applied to the wrap portion in consideration of the wrap margin.

When the printed resin film is adhered so as to have the same length as the circumferential length of the can body or to be slightly shorter, both ends of the resin film are abutted. Therefore, the top coat and the adhesive are applied over the entire surface of one can.

When the resin film is attached (laminated) to the outer surface of the can body of the metal can body for a two-piece can and the printed resin film manufactured as described above, a flat metal plate is used. Unlike the case where a resin film is adhered to the outer surface of a can body formed into a cylindrical shape, that is, a curved surface, the temperature, pressure, and speed, which are important requirements for the bonding conditions, are different from those in the case where a resin film is bonded. It is difficult to secure a sufficient pressing force within. Therefore, in order to sufficiently wet the adhesive on the metal surface, it is necessary to lower the viscosity (melt viscosity) of the adhesive at the temperature at the time of bonding.

The printed resin film is adhered over the entire circumference of the cylindrical can body. However, as described above, the printed resin film is longer than the circumferential length of the can body so that characters and designs are not cut off in the middle. When the wrap is formed by sticking it a little longer, the inside of the overlap of the wrap tends to become a gap, and it is better for the adhesive to protrude and enter this gap. A lower melt viscosity is advantageous.

However, if the melt viscosity of the adhesive is too low, a phenomenon occurs in which the adhesive protrudes from the printed resin-made film, and if this protrudes severely, the printed appearance is impaired, which is not preferable.

Although the melt viscosity of the adhesive varies depending on the molecular weight of the resin constituting the adhesive and the degree of curing of the adhesive, the above-mentioned protrusion is caused by the fact that the adhesive condition for sticking the printed resin film is determined. Glass transition temperature (T
g) is almost determined. For this reason, the adhesive preferably has a glass transition temperature (Tg) in the range of 0 to 40 ° C, and more preferably 10 to 40 ° C. (Note that, in the case of a thermosetting adhesive or an adhesive which is a combination of a thermosetting adhesive and an electron beam-curing adhesive as described above, the semi-dry state in which the adhesive is not cured means such a meaning. Including.)

The temperature and pressure conditions for sticking the printed resin film are as follows.
Heat to 220 ° C, pressure is 20-60kgf / c at linear pressure
m.

That is, the can is inserted and held in the mandrel, and is heated by indirect heating such as heating the mandrel to propagate heat to the can, direct heating such as high-frequency induction heating, or a combination thereof, and the can body temperature ( The surface temperature of the can is 130 to 220 ° C., but if the temperature is lower than 130 ° C., the temperature is not enough, and even if the pressure is increased, the adhesive is not sufficiently wetted to the can and the adhesion is insufficient. Therefore, peeling is likely to occur, which is not preferable.

On the other hand, when the temperature of the can exceeds 220 ° C., even if the pressure is lowered, sufficient wetting of the can is ensured, but the above-mentioned adhesive overflows too much and the printed resin film is formed. In the wrap portions (overlap portions) at both ends of the above, the adhesive force is advantageous, but the print appearance is impaired, which is not preferable.

In order to avoid the above-mentioned phenomenon, if the pressure is applied at a pressure lower than 20 kgf / cm, an uneven pressure distribution may occur overall, or a poor adhesion may occur locally, This is not preferable because peeling may occur during the retort treatment.

For the reasons described above, the temperature and pressure conditions for sticking (laminating) the printed resin film are as follows: the temperature of the can is heated to 130 to 220 ° C .; Optimally, it is ６０60 kgf / cm. This is also confirmed by the following Experimental Example 4.

[Experimental Example 4] Using a chemical conversion can having the same coating C amount of 19 mg / m ² as in Test No. 4 of Experimental Example 1, the lamination conditions were as follows: pressure 50 kgf / cm, speed 160 m.
The printed resin film used in Experimental Example 1 was adhered (laminated) at a rate of / min only by changing the can body temperature. The external appearance of the adhesive of the film-attached can thus obtained was examined. After that, the inner surface of the can was further spray-painted and dried at 200 ° C. for 60 seconds.
After performing a multi-stage neck-in process to make the can into a reduced diameter can, the retort process was performed at 125 ° C. for 30 minutes, and the state of peeling of the resin film at the neck processed portion was examined.
The results are shown in Table 4 below.

[0092]

[Table 4]

From Table 4 above, it can be seen that the test No. 20 (which is not based on the above-mentioned production method) has no adhesive protrusion and is good, but has poor adhesion. Also,
Test No. 26 (not based on the above manufacturing method)
Although the adhesiveness is relatively good and has practicality, it can be seen that the printing appearance due to the protrusion of the adhesive is inferior. On the other hand, in Test Nos. 21 to 25 (according to the above-described production method), it was found that the adhesive hardly protruded and the adhesion was good.

After the printed resin film is attached (laminated) to the outer surface of the can body of the can body under the above temperature conditions, an electron beam-curable adhesive, or a thermosetting adhesive and an electron beam-curable adhesive are used. In the case of a combined adhesive, the curing of the adhesive is further promoted by irradiating an electron beam. In the case of a thermosetting adhesive,
If necessary, it is further heated to accelerate the curing, but the reheating at this time can be performed again by passing through the same heating furnace (for example, a hot blast furnace). It is also possible to use together with heating performed for other necessity.

Finally, the can body having the printed resin film adhered to the outer surface of the can body as described above is further subjected to neck-in processing for narrowing the opening at the upper end of the can body, and the can lid is tightened. To perform the necessary flange processing,
In the present embodiment, the diameter reduction ratio (working degree) of the upper end portion of the can body by neck-in processing is limited to 79 to 87% with respect to the diameter of the can body. The reason for this is that, as described above, the characteristics of the organic-inorganic composite chemical conversion treatment film are exhibited in such a large-diameter reduction process.

[0096] The method of neck-in processing and flange processing itself is not particularly limited, and a method generally used at present is applicable. For example, in neck-in processing, die neck processing is performed. A processing technique such as spin neck processing or a combination thereof can be applied.

[0097] The embodiment 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, the printed resin film adhered to the can body is not limited to the resin film composed of the top coat layer / thermoplastic resin film layer / printing ink layer / adhesive layer. Any printed resin film having a plastic resin film layer, a printing ink layer, and an adhesive layer may be used. In addition, a printed resin having other layers such as a hologram forming layer and a metal deposition layer formed thereon It is also possible to carry out using a film made.

[0098]

According to the film-attached can body of the present invention as described above, the resin can is printed on the surface of the can body of a metal can body in which the can body and the can bottom are integrally formed. By sticking the film, it is not only possible to simply add printed characters and printed patterns to the can body of the can container, but also to obtain a can container with beautiful printed finish and appearance, and to diversify the contents. In addition to being able to sufficiently respond to the differentiation of the accompanying products, the total cost of the can can be kept low by greatly reducing the diameter of the upper end of the can body. Can effectively prevent the problem of peeling of the resin film at the neck portion which occurs when the diameter of the resin film is reduced. Further, according to the production method of the present invention, the film-attached can body of the present invention having the above-mentioned effects is obtained in a state where the adhesion between the resin film and the surface of the can body is kept good by the adhesive. In addition, the adhesive can be manufactured with an excellent appearance without protruding.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Sachiko Otahara 5-5-1 Nishihashimoto, Sagamihara City, Kanagawa Prefecture Inside Daiwa Seikan Co., Ltd. (72) Inventor Kenichi Uematsu 5-5 Nishihashimoto, Sagamihara City, Kanagawa Prefecture No. 1 Daiwa Seikan Co., Ltd. Research Laboratory (72) Inventor Kiyoshi Hirotsuji 5-5-1 Nishihashimoto, Sagamihara-shi, Kanagawa F-term in the Technology Development Center of Daiwa Seikan Co., Ltd. 3E033 AA07 BA07 BA13 BB08 CA09 CA16 DA01 DA08 EA09 FA01 3E061 AA16 AB04 AC09 AD03 AD09 BA01 BB05 DB01 DB08 3E062 AA04 AC03 DA01 DA02 DA09 JA04 JA08 JB26 JC09 JD10 4K026 AA02 AA09 AA25 BA01 BA03 BB06 BB08 BB10 CA16 CA39

Claims (2)

[Claims] 1. A metal can body in which a can body and a can bottom are integrally formed, at least a top coat layer, a printing ink layer, and an adhesive layer are formed on a main layer of a thermoplastic resin film. In a film-adhered can body in which a resin film is adhered to an outer surface of a can body of the metal can through an adhesive layer of the resin film, a can body to which a resin film is adhered 1 to 7 mg / m ² as phosphorus (P) adhesion amount and 5 to 50 m as coating carbon (C) amount with respect to the metal surface of
g / m ² , and the ratio of the amount of carbon deposited to the amount of phosphorus deposited (C /
An organic-inorganic composite chemical conversion treatment film having P) of 2 to 10 is formed, and the diameter of the opening at the upper end of the can body is reduced to 79 to 87% of the diameter of the can body. A film-adhered can body characterized in that it is formed into a film. 2. A metal can body in which a can body and a can bottom are integrally formed, the upper end of the can body is cut, and the can body is trimmed to a predetermined can height. after degreasing treatment, immediately, from 1 to 7 mg / m ² as phosphorus (P) adhering amount, 5 to 50 mg / m ² as a film of carbon (C) content, and the ratio of the coating amount of carbon and phosphorus deposition amount (C / P ) Is a chemical conversion treatment film for forming an organic-inorganic composite chemical conversion treatment film having a thickness of 2 to 10 on the metal surface of the can body, and then heating the can body to 130 to 220 ° C. A resin film having at least a top coat layer, a printing ink layer, and an adhesive layer formed on the main layer is thermally bonded to the outer surface of a cylindrical can body of the can body via the adhesive layer. After painting and drying the inner surface, the diameter of the opening at the upper end of the can body is 79-87 with respect to the diameter of the can body. %. A method for producing a film-adhered can body, wherein neck-in processing is performed so as to reduce the diameter of the film, and further flange processing is performed.