JP2002211560A - Pull-out type can and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pull-top type can capable of protecting contents stored in a can main body without damaging unsealability by a pull-top mechanism fixed to a lid member, and without producing any hair rings at an outer circumferential part of unsealing segment of the lid member. SOLUTION: There are provided a can main body having its upper part opened and having its inner surface laminated by an organic resin film, and an aluminum lid member press fitted to an opening part of the can main body and having a pull-top mechanism. The lid member is directly coated by a thermal lamination with a thermal bonding organic resin film of thickness of about 5 to 15 μm at its outer surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pull-top can and a method for manufacturing a pull-top can, and more particularly to a pull-top can with an improved lid and a method for manufacturing a pull-top can.

[0002]

2. Description of the Related Art Recently, as a can containing soft drinks, beer, and other seafood, a can having a structure having a lid having a pull-top mechanism that can be easily opened is known.

[0003] A conventional pull-top type can comprises a can body made of steel or aluminum having an open top, and a lid which is caulked to the opening of the can body and has a pull-top mechanism. For example, in the case of a soft drink can, the pull-top mechanism is formed by joining an opening formed by a horseshoe-shaped groove formed on the lid by pressing to a pin on the outside of the lid so as to contact the surface thereof. And tabs. Such a pull-top mechanism is opened by bending the lid portion located inside the horseshoe-shaped opening portion toward the can body side by vertically raising the tab with a finger. The lid is made of soft aluminum so that a cut can be easily formed along the horseshoe-shaped opening of the pull-top mechanism.

For example, an organic resin film such as a polyethylene terephthalate film is laminated on the inner surface of the can body, and the quality of the film deteriorates due to the direct contact of the contents with steel or aluminum as the material of the can body. Has been prevented.

On the other hand, the inner surface of the lid to which the pull-top mechanism is attached is baked and coated with, for example, a submicron-order epoxyphenol-based resin thin film, so that the contents of the lid can be reduced without impairing the openability of the pull-top mechanism. Protection without direct contact with aluminum.

However, the baking coating of the epoxy phenolic resin thin film on the inner surface of the lid not only deteriorates the working environment but also requires a large amount of water for washing after the coating, thereby increasing running costs. Further, there is a problem that the resin thin film baked on the inner surface of the lid has a lower effect of protecting the contents than the organic resin film laminated on the inner surface of the can body.

[0007] Under such circumstances, the present applicant has proposed a pull-top can (JP-A-11-171179) in which the lid is improved. The pull-top can has an open top, a can body having an inner surface laminated with an organic resin film, and an aluminum lid having a pull-top mechanism, which is caulked to the opening of the can body and has a pull-top mechanism. The lid has a structure in which a porous organic resin film having a large number of fine through holes or non-through holes on the outer surface and the inner surface is laminated via an adhesive layer. Another pull-top can has an open top, a can body having an inner surface laminated with an organic resin film, and an aluminum lid having a pull-top mechanism, which is caulked and joined to the opening of the can body. The lid is formed by laminating a porous organic resin film having a large number of fine through holes or non-through holes on an outer surface thereof through an adhesive layer, and laminating an organic resin film on the inner surface thereof through a fragile adhesive layer. It has a structure.

[0008] The above-mentioned pull-top can can prevent hairing around the opening portion of the lid without impairing the openability of the pull-top mechanism attached to the lid. However, when a plurality of pull-top cans were opened by a later study of the present inventors, hairing called an angel mark occurred around the outside of the opening in some pull-top cans.

[0009]

SUMMARY OF THE INVENTION According to the present invention, the outer surface of the lid can be protected without impairing the openability by the pull-top mechanism attached to the lid, and the occurrence of hair ring around the outside after the lid is opened. It is intended to provide a prevented pull-top can.

According to the present invention, there is provided a pull-top type can which can protect the outer surface of the lid without impairing the opening property by the pull-top mechanism attached to the lid, and which prevents the occurrence of hairing around the outside after the lid is opened. It is intended to provide a method that can be manufactured at low cost.

[0011]

SUMMARY OF THE INVENTION A pull-top can according to the present invention has a can body having an open top and an inner surface laminated with an organic resin film, and a pull-top mechanism attached to the opening of the can body. A lid made of aluminum, wherein the lid is directly thermally laminated with a thermally fusible organic resin film having a thickness of 5 to 15 μm on an outer surface thereof.

[0012] Another pull-top can according to the present invention is a can body having an upper opening and an inner surface laminated with an organic resin film, and an aluminum lid attached to the opening of the can body and having a pull-top mechanism. Body, wherein the lid is directly thermally laminated with a porous heat-fusible organic resin film having a large number of at least one hole selected from fine through holes and non-through holes on the outer surface. It is a feature.

[0013] The method of manufacturing a pull-top can according to the present invention comprises a can body having an opening at an upper portion and an inner surface laminated with an organic resin film; and an aluminum body attached to the opening of the can body and having a pull-top mechanism. In manufacturing a pull-top can having a lid, a hot-melt resin is coated on one side of an aluminum thin plate to form a hot-melt resin layer.
After thermally laminating an organic resin film having a thickness of 2 μm, the outer shape processing and the formation of the pull-top mechanism are performed to produce a lid in which the organic resin film is located on the outer surface side.

Another method of manufacturing a pull-top can according to the present invention is directed to a can body having an upper portion opened and an inner surface laminated with an organic resin film, and an aluminum having a pull-top mechanism attached to the opening of the can body. In the manufacture of a pull-top can having a lid made of aluminum, a hot melt resin is coated on one side of an aluminum thin plate to form a hot melt resin layer, and the hot melt resin layer is selected from fine through holes and non-through holes. After thermally laminating a porous organic resin film having a large number of at least one hole, a step of producing a lid in which the porous organic resin film is located on the outer surface side by performing outer shape processing and forming the pull-top mechanism. It is characterized by having.

[0015] Still another method of manufacturing a pull-top can according to the present invention includes a can body having an open upper portion and an inner surface laminated with an organic resin film, and a pull-top mechanism attached to the opening of the can body. In manufacturing a pull-top can equipped with an aluminum lid, a heat-fusible organic resin film is directly thermally laminated on one side of an aluminum thin plate, and a large number of fine non-through holes are formed in the heat-fusible organic resin film. After the perforation, there is provided a step of producing a lid in which the porous heat-fusible organic resin film is located on the outer surface side by performing outer shape processing and forming the pull-top mechanism. .

Another method of manufacturing a pull-top can according to the present invention is directed to a can body having an upper portion opened and an inner surface laminated with an organic resin film, and an aluminum having a pull-top mechanism attached to the opening of the can body. In the manufacture of a pull-top can equipped with a lid made of aluminum, an organic resin film was thermally laminated on one side of an aluminum thin plate via an adhesive layer, and a number of fine non-through holes were formed in the organic resin film. The method further comprises a step of producing a lid in which the perforated organic resin film is positioned on the outer surface side by performing external processing and forming the pull-top mechanism.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A pull-top type can and a method for producing the pull-top can according to the present invention will be described below in detail with reference to the drawings.

(First Embodiment; Pull-Top Can) This pull-top can is attached to a can body having an open upper part and an inner surface laminated with an organic resin film, by caulking, for example, to the opening of the can body. And an aluminum lid having a pull-top mechanism. This lid body is directly thermally laminated with a heat-fusible organic resin film having a thickness of 5 to 15 μm on the outer surface.

The can body is made of, for example, steel or aluminum.

As the organic resin film laminated on the inner surface of the can body, for example, a polyester film,
Oriented polypropylene films and the like can be mentioned. The can body allows an organic resin film such as a polyester film or an oriented polypropylene film to be laminated on the outer surface.

The lid usually has a thickness of 280 to 340 μm.

For example, in the case of a soft drink can, the pull-top mechanism includes an opening portion formed of a horseshoe-shaped groove formed in the lid by pressing, and an outer surface of the lid so as to contact the surface thereof. And a pin-joined tab.

As the heat-fusible organic resin film,
Amorphous non-stretched polyethylene terephthalate film, non-stretched polypropylene film, ionomer resin film, etc. A density polyethylene film or the like can be used. In particular, an amorphous unstretched polyethylene terephthalate film having excellent adhesion to the outer surface of the lid and tearing property upon opening is preferable.

The thickness of the heat-fusible organic resin film is 5
When the thickness is less than μm, it is difficult to protect the outer surface of the lid well. On the other hand, if the thickness of the heat-fusible organic resin film exceeds 15 μm, the opening property by the above-described pull-top mechanism may be impaired.

It is permitted to laminate an easily breakable organic resin film described below on the inner surface of the lid. By laminating such an easily breakable organic resin film on the inner surface of the lid, it is possible to prevent the contents of the can from directly contacting aluminum, which is a material of the lid, and to protect the contents. become.

(1) A form in which a heat-fusible organic resin film having a thickness of 5 to 15 μm is directly thermally laminated on the inner surface of the lid.

The same heat-fusing organic resin film as that laminated on the outer surface of the lid described above can be used.

(2) A mode in which a porous heat-fusible organic resin film having a large number of at least one hole selected from fine through holes and non-through holes is directly laminated on the inner surface of the lid by thermal lamination.

As the heat-fusible organic resin film,
Amorphous non-stretched polyethylene terephthalate film, non-stretched polypropylene film, ionomer resin film, etc. A density polyethylene film or the like can be used. In particular, an amorphous unstretched polyethylene terephthalate film having excellent adhesion to the inner surface of the lid and excellent tearing property upon opening is preferable.

The porous heat-fusible organic resin film preferably has a thickness of 5 to 30 μm. When the thickness of the porous heat-fusible organic resin film is less than 5 μm, there is a possibility that the protection of the contents accommodated in the can cannot be sufficiently achieved. On the other hand, when the thickness of the porous heat-fusible organic resin film exceeds 30 μm, the tearability is reduced even if a large number of fine holes are formed in the heat-fusible organic resin film of this thickness. There is a possibility that the opening property by the above-mentioned pull-top mechanism may be impaired. The thickness of the porous heat-fusible organic resin film is more preferably 9 to 25 μm.

The porous heat-fusible organic resin film is manufactured by making the heat-fusible organic resin film porous by a porous film manufacturing apparatus disclosed in Japanese Patent Publication No. 6-61859. . The manufacturing apparatus includes a supply unit for supplying a long film; a first rotatable roll having a large number of particles having a Mohs hardness of 5 or more (for example, diamond particles) having sharp corners adhered to a surface thereof; And a second roll rotatable in the opposite direction with respect to the first and second rolls are arranged to face each other so that the long film passes between them, A punching unit in which one of the rolls is fixed and the other is movably arranged in the direction opposite to the one of the rolls; provided in the vicinity of both ends of the movable roll of the unit; Pressure adjusting means for adjusting the pressing force on the film.

[0032] In the porous heat-fusible organic resin film, at least one hole selected from a through-hole having an average opening diameter of 0.5 to 100 µm and a non-through-hole has 500 holes.
It is preferable that the hole is formed at a density of not less than the number of holes / cm ² . The porous organic resin film having pores having such an average opening diameter and density has a tear strength sufficiently lower than that of the heat-fusible resin film in a non-porous state, and compared to the same film in a non-porous state. Shows high tearability (breakability). In particular,
From the viewpoint of protecting the contents in the can, it is preferable to use a porous heat-fusible organic resin film having a large number of non-through holes.

The reason why the average opening diameter of the pores in the porous heat-fusible organic resin film is specified is as follows. When the average opening diameter is less than 0.5 μm, when the porous heat-fusible organic resin film is opened by a pull-top mechanism on a lid laminated on the inner surface, it becomes difficult to improve the openability. There is a fear. On the other hand, if the average opening diameter exceeds 100 μm, there is a possibility that the protection of the contents contained in the can cannot be sufficiently achieved. More preferably, the average opening diameter of the holes (through holes, non-through holes, or holes in which the through holes and the non-through holes are mixed) is 2 to 50 μm.

The reason why the density of the pores in the porous heat-fusible organic resin film is specified is as follows. When the density is less than 500 pieces / cm ² , and when the thickness is less than μm, when the lid having the porous heat-fusible organic resin film laminated on the inner surface is opened by a pull-top mechanism, the opening property is improved. This may be difficult. The upper limit of the density is not particularly limited. However, through-holes or non-through-holes having a density of 25,000 / cm ² can be formed in a single treatment by the above-described porous film manufacturing apparatus. More preferably, the density of the holes (through holes, non-through holes or holes in which through-holes and non-through holes are mixed) is 1000 / c.
m ² -5000 / cm ² .

(3) The inner surface of the lid has a thickness of 5 to 12 μm.
Form in which the organic resin film is thermally laminated via an adhesive layer.

In the thermal laminating step, a hot melt resin layer (adhesive layer) is co-extruded onto the organic resin film to form a laminated film, and the laminated film is placed on the inner surface of a lid. This is performed by arranging it so as to be located on the lid side and performing thermal lamination. Further, after a hot melt resin is coated on the inner surface of the lid to form a hot melt resin layer, an organic resin film may be thermally laminated on the hot melt resin layer by a hot roll method or the like.

As the organic resin film, for example, a polyester film such as a polyethylene terephthalate film, a nylon film, an oriented polypropylene film and the like can be used.

If the thickness of the organic resin film is less than 5 μm, there is a possibility that the protection of the contents contained in the can cannot be sufficiently achieved. On the other hand, when the thickness of the organic resin film exceeds 12 μm, there is a possibility that the opening property by the above-described pull-top mechanism is impaired.

As the hot melt resin, general ones applicable to foods can be used, and for example, polyester hot melt resins and nylon hot melt resins can be used. The thickness of the hot melt resin layer is preferably 2 to 5 μm from the viewpoint of tearability and protection of contents.

(4) A mode in which a porous organic resin film having a large number of at least one hole selected from fine through holes and non-through holes is thermally laminated through an adhesive layer on the inner surface of the lid.

In the thermal laminating step, the hot melt resin layer (adhesive layer) is co-extruded with the porous organic resin film to form a laminated film, and the laminated film is coated on the inner surface of the lid with the hot melt resin layer. This is performed by arranging them so as to be located on the lid side and performing thermal lamination. Further, a hot melt resin may be coated on the inner surface of the lid to form a hot melt resin layer, and then a porous organic resin film may be thermally laminated on the hot melt resin layer by a hot roll method or the like.

As the organic resin, for example, polyester such as polyethylene terephthalate, nylon, oriented polypropylene and the like can be used.

The porous organic resin film has a thickness of 5 to 40.
It preferably has a thickness of μm. If the thickness of the porous organic resin film is less than 5 μm, there is a possibility that the protection of the contents accommodated in the can cannot be sufficiently achieved.
On the other hand, if the thickness of the porous organic resin film exceeds 40 μm, even if a large number of fine holes are formed in the organic resin film of this thickness, the tearing property is lowered and the opening property by the pull-top mechanism described above is impaired. There is a possibility that it will be. More preferably, the thickness of the porous organic resin film is 9 to 25 μm.

The porous organic resin film has a thickness of 0.5 to
At least one hole selected from a through-hole and a non-through-hole having an average opening diameter of 100 μm (through-holes, non-through-holes or holes in which through-holes and non-through-holes are mixed) is opened at a density of 500 / cm ² or more It preferably has a perforated form. The porous organic resin film having pores with such an average opening diameter and density has a tear strength sufficiently lower than that of the non-porous organic resin film, and has a higher tearability than the non-porous organic resin film. (Breakability).

The reason why the average opening diameter of the pores of the porous organic resin film is specified is as follows. If the average opening diameter is less than 0.5 μm, it may be difficult to easily open the lid with the porous organic resin film laminated on the inner surface by a pull-top mechanism. On the other hand, if the average opening diameter exceeds 100 μm, there is a possibility that the protection of the contents contained in the can cannot be sufficiently achieved. More preferably, the average opening diameter of the holes (through holes, non-through holes, or holes in which the through holes and the non-through holes are mixed) is 2 to 50 μm.

The reason why the pore density of the porous organic resin film is specified is as follows. When the density is less than 500 pieces / cm ² , it becomes difficult to laminate a porous organic resin film having high tearability on the inner surface of the lid. The upper limit of the density is not particularly limited. However, holes having a density of 25,000 holes / cm ² can be formed by one treatment using the above-described porous film manufacturing apparatus. More preferably, the density of the holes (through-holes, non-through-holes or holes in which through-holes and non-through-holes are mixed) is 1,000 / cm ^{2 to} 5,000 / c
m ² .

As the hot melt resin, general ones applied to foods can be used, and for example, polyester hot melt resins and nylon hot melt resins can be used. The thickness of the hot melt resin layer is preferably 2 to 5 μm from the viewpoint of tearability and protection of contents.

The above-mentioned lid is manufactured, for example, by the following method.

First, the above-mentioned thin heat-fusible organic resin film is directly thermally laminated on one surface (the outer surface in the state of a lid) of an aluminum thin plate. Subsequently, the easily breakable organic resin film of the above-described forms (1) to (4) is laminated on the other surface (the inner surface in the state of the lid) of the aluminum thin plate. The aluminum thin plate is punched into a circular shape, pressed on the first surface to form an unsealed portion formed of a horseshoe-shaped groove, and the like, and a tab is joined to the first surface with a pin.

Next, the pull-top can of the first embodiment will be described more specifically with reference to the drawings.

FIG. 1 is a top view of a pull-top can for soft drinks of the first embodiment, FIG. 2 is a front view of the pull-top can of FIG. 1, and FIG. 3 is a lid used for the pull-top can of FIG. FIG. 4 is a cross-sectional view of a shoulder of the pull-top can of FIG. 2, and FIG. 5 is an enlarged cross-sectional view of the lid of FIG.

The can body 1 made of, for example, steel having an open upper portion has an organic resin film 2 such as a polyethylene terephthalate film laminated on the inner surface. An organic resin film such as a polyethylene terephthalate film (not shown) is also laminated on the outer surface of the can body 1.

The aluminum lid 3 is connected to the can main body 1.
Is crimped to the opening. The thermally fusible organic resin films 4 and 5 having a size of 5 to 15 μm are directly thermally laminated on the outer surface and the inner surface of the lid 3 as shown in FIGS.

The pull-top mechanism 6 is formed on the lid 3. As shown in FIGS. 1 and 3, the pull-top mechanism 6 is formed by pressing a shoe-shaped dent 7 formed on the outer surface of the lid 3 by pressing and a curved surface area of the dent 7. An unsealing portion 8 formed of a horseshoe-shaped groove in which a cut is formed at the time of unsealing, and a recess 9 on the opposite side to the unsealing portion 8 are joined by a pin 9 located near the center, and are attached to the surface of the recess 7. And an elongated tab 10 having two holes that abut.

The inner surface of the lid 3 is not limited to the structure shown in FIG. 5, but may have the following structure.

For example, as shown in FIG. 6, a porous heat-fusible organic resin film having a large number of at least one hole selected from the fine through-holes and the non-through-holes described in the above (2) (for example, a heat-fusible organic resin film). A porous heat-fusible organic resin film 13) having a large number of fine non-through holes 12 formed in the adhesive organic resin film 11 may be directly thermally laminated on the inner surface of the lid 3.

As shown in FIG. 7, the thin organic resin film 14 having a thickness of 5 to 12 μm described in the above (3) is thermally laminated on the inner surface of the lid 3 via the hot melt resin layer (adhesive layer) 15. You may.

As shown in FIG. 8, a porous organic resin film having a large number of at least one hole selected from the fine through-holes and the non-through holes described in the above (4) (for example, a large number of fine The porous organic resin film 18 having the through holes 17 may be thermally laminated on the inner surface of the lid 3 via a hot melt resin layer (adhesive layer) 15.

The pull-top can according to the first embodiment described above has a can body with an open top and at least an inner surface laminated with an organic resin film, and is attached to the opening of the can body by caulking, for example. An aluminum lid having a mechanism. The lid has a thermally fusible organic resin film having a thickness of 5 to 15 μm directly thermally laminated on an outer surface thereof.

In the pull-top can having such a structure, as shown in FIGS. 9 and 10, the can main body 1 is held by one hand (not shown), and the finger of the other hand (not shown) is used. When the tab 10 of the pull-top mechanism 6 is erected vertically, the end of the dove 10 near the joint of the pin 9 is located on the inside of the horseshoe-shaped opening 8 as shown in FIG. The surface is pressed toward the can body 1 side. When the end of the tab 10 is pressed, the heat-fusible organic resin film 4 having a thickness of 5 to 15 μm is directly thermally laminated on the outer surface of the lid 3. For this reason, notches are formed along the grooves of the horseshoe-shaped opening 8 not only in the lid 3 but also in the heat-fusible organic resin 4, as shown in FIGS. 9 and 10. The lid 3 inside the opening 8 is bent toward the inside of the can body 1 and opened.
At this time, the lid 3 can be opened without any hair ring called an angel mark on the outside of the lid 3.

More specifically, when the end of the tub 10 presses the lid 3 inside the horseshoe-shaped opening 8, the thermally fusible organic resin film 4 directly thermally laminated on the outer surface of the lid 3 is pressed. Since the thickness is as thin as 5 to 15 μm, a cut is formed along the groove of the unsealing portion 8 located around the pressing portion at the initial stage of the pressing as shown in FIGS. A cut is also formed in the heat-fusible organic resin film 4 along the groove of the opening 8. Further, when the tab 10 is raised upright, the pressing stroke on the lid 3 located inside the horseshoe-shaped opening 8 becomes longer. For this reason, the groove of the opening 8 is cut long together with the heat-fusible organic resin film 4, and the cover 3 inside the horseshoe-shaped opening 8 is bent toward the inside of the can body 1. Then, the lid 3 can be opened without any hair ring called an angel mark on the outside of the lid 3.

By the way, the present inventor studied a mechanism of causing hairing in the pull-top type can disclosed in Japanese Patent Application Laid-Open No. 11-171179 described in the prior art. As a result, when a porous organic resin film is laminated on the outer surface of the lid of the pull-top can, a heat-fusible adhesive (for example, a two-component polyester polyurethane-based adhesive) is co-extruded onto the porous organic resin film. The laminated film is placed on the outer surface of the lid so that the adhesive layer is positioned on the lid side and is subjected to thermal lamination. Therefore, the thickness of the adhesive layer is not controlled, and the laminated film is partially improper. It has been clarified that the uniformity is obtained and that the stretchability of the adhesive layer is higher than that of the porous organic resin film. That is, when the lid portion located inside the horseshoe-shaped opening portion is bent toward the inside of the can main body at the time of pressing the tab end described above, the porous organic resin film is easily broken. This causes a layer separation failure at the boundary of the adhesive layer (particularly at the position of the adhesive layer having a small thickness) so that the adhesive layer extends without following the breakage of the porous organic resin film. It has been found that hairing called the angel mark occurs at the position (1).

In view of the above, by directly thermally laminating a heat-fusible organic resin film 4 having a thickness of 5 to 15 μm on the outer surface of the lid 3, the tab 1
When the lid 3 located inside the horseshoe-shaped opening 8 is bent toward the inside of the can body 1 by pressing the 0 end, the heat-fusible organic resin film 4 is closed by the lid. Without causing layer separation destruction near the interface of the outer surface of the body 3,
Lid 3 easily broken and using an adhesive layer
Can be opened without any hair ring called an angel mark on the outer surface of the cover.

The inner surface of the lid 3 has the same thickness 5 as the outer surface.
By directly thermally laminating a heat-fusible organic resin film 5 having a thickness of about 15 μm,
At the time of opening, it is possible to prevent the occurrence of hair ring called feathering on the inner surface side of the lid 3 without impairing the opening property. In addition, as shown in FIGS. 6 to 8 described above, even in a structure in which an easily breakable organic resin film is laminated on the inner surface of the lid 3, when the pull-top mechanism 6 is opened, the openability is not impaired. Body 3
It is possible to prevent the occurrence of hair ring called feathering on the inner surface side.

Therefore, the pull-top type can of the first embodiment is provided with a heat-fusible organic resin film having a thickness of 5 to 15 μm directly laminated on the outer surface of the lid without impairing the openability of the pull-top mechanism. In addition, it can be easily opened without causing hairing called an angel mark that impairs the appearance. In addition, the outer surface of the lid can be protected from the outside by directly thermally laminating the outer surface of the lid with a heat-fusible organic resin film.

Also, by thermally laminating an organic resin film on the inner surface of the can body and directly thermally laminating a thin heat-fusible organic resin film on the inner surface of the lid body, the contents in the can can be reduced by the can body and the can body. The quality can be maintained for a long period of time by preventing oxidation or the like caused by direct contact with a material such as aluminum of the lid.

Further, since the heat-fusible organic resin film on the outer surface and the inner surface of the lid can be coated by a laminating method, a washing step requiring an enormous amount of water after coating as in the conventional baking coating is omitted. As a result, running costs can be significantly reduced.

(Second Embodiment; Pull-Top Can) This pull-top can has an opening at the top and an inner surface laminated with an organic resin film, and is attached to the opening of the can body by caulking, for example. An aluminum lid having a mechanism. This lid is
A porous heat-fusible organic resin film having a large number of at least one hole selected from fine through holes and non-through holes on the outer surface is directly thermally laminated.

The can body is made of, for example, steel or aluminum.

The lid usually has a thickness of 280 to 340 μm.

For example, in the case of a soft drink can, the pull-top mechanism includes an opening portion formed of a horseshoe-shaped groove formed in the lid by pressing, and an outer surface of the lid so as to contact the surface thereof. And a pin-joined tab.

The porous heat-fusible organic resin film is produced by making the heat-fusible organic resin film porous by a porous film production apparatus disclosed in Japanese Patent Publication No. 6-61859. .

Examples of the heat-fusible organic resin film to be made porous include amorphous materials such as Okura Kogyo's Oster Copolyester film, which is an inflation film of Eastman's Ooster Copolyester (amorphous polyester). Unstretched polyethylene terephthalate film, unstretched polypropylene film, ionomer resin film, low density polyethylene film and the like can be used. In particular, an amorphous unstretched polyethylene terephthalate film having excellent adhesion to the outer surface of the lid and tearing property upon opening is preferable.

The porous heat-fusible organic resin film preferably has a thickness of 5 to 30 μm. If the thickness of the porous heat-fusible organic resin film is less than 5 μm, it may be difficult to effectively protect the outer surface of the lid. On the other hand, when the thickness of the porous heat-fusible organic resin film exceeds 30 μm, even if a number of fine through holes or non-through holes are formed in the organic resin film of this thickness, the above-described pull-top mechanism is used. Opening properties may be impaired. More preferably, the thickness of the porous heat-fusible organic resin film is 9 to 25 μm.

In the porous heat-fusible organic resin film, at least one hole selected from a through-hole having an average opening diameter of 5 to 100 μm and a non-through-hole is 500 / hole.
It is preferable that the pores are formed at a density of not less than cm ² . The porous organic resin film having pores having such an average opening diameter and density has a tear strength sufficiently lower than that of the heat-fusible resin film in a non-porous state, and compared to the same film in a non-porous state. Shows high tearability (breakability). In particular, from the viewpoint of enhancing tearability, it is preferable to use a porous heat-fusible organic resin film having a large number of through holes.

The reason why the average opening diameter of the holes in the porous heat-fusible organic resin film is specified is as follows. If the average opening diameter is less than 5 μm, it may be difficult to easily open the lid with the porous heat-fusible organic resin film laminated on the outer surface by a pull-top mechanism. On the other hand, if the average opening diameter exceeds 100 μm, moisture and the like easily penetrate, causing corrosion at the rib portion with the main body, and it may be difficult to effectively protect the lid. More preferably, the average opening diameter of the holes (through holes, non-through holes or holes in which the through holes and the non-through holes are mixed) is 5 to 50 μm.

The pore density in the porous heat-fusible organic resin film is defined for the following reason. When the density is less than 500 pieces / cm ² , it is difficult to laminate a porous heat-fusible organic resin film having a high tearing property on the outer surface of the lid.
The upper limit of the density is not particularly limited. However, through-holes or non-through-holes having a density of 25,000 / cm ² can be formed in a single treatment by the above-described porous film manufacturing apparatus. More preferably, the density of the holes (through-holes, non-through-holes or holes in which through-holes and non-through-holes are mixed) is from 1,000 / cm ^{2 to} 5000 / cm ² .

In the case where the porous heat-fusible organic resin film has a large number of non-through holes, even if thermal lamination is performed so that the openings of the large number of non-through holes are located on the outer surface side of the lid, Thermal lamination may be performed so that the opening of the non-through hole is located on the side opposite to the outer surface of the lid.

It is permissible to laminate the easily breakable organic resin film of (1) to (4) described in the first embodiment on the inner surface of the lid. By laminating such an easily breakable organic resin film on the inner surface of the lid, it is possible to prevent the contents of the can from directly contacting aluminum, which is a material of the lid, and to protect the contents. become.

The above-mentioned lid is manufactured, for example, by the following method.

First, a porous heat-fusible organic resin film having a large number of at least one hole selected from the above-mentioned fine through-holes and non-through-holes on one surface (the outer surface in the state of a lid) of an aluminum thin plate. Directly thermal laminate. Subsequently, an easily breakable organic resin film having the above-described forms (1) to (4) is laminated on the other surface (the inner surface in the state of the lid) of the aluminum thin plate. This aluminum thin plate is punched into a circular shape, pressed on the one surface to form an unsealed portion formed of a horseshoe-shaped groove, and then a tab is joined to the one surface by a pin.

Next, the pull-top can of the second embodiment will be described more specifically with reference to the drawings. FIG.
FIG. 14 is a cross-sectional view of a shoulder of a pull-top can for soft drinks according to the second embodiment, and FIG. 14 is an enlarged cross-sectional view of the lid of FIG. 13. 13 and 14 described above with reference to FIGS.
The same members as those described above are denoted by the same reference numerals and description thereof is omitted.

The aluminum lid 3 is caulked to the opening of the can body 1 as shown in FIG. As shown in FIG. 13, the porous heat-fusible organic resin films 21 and 22 are directly thermally laminated on the outer surface and the inner surface of the lid 3, respectively. The porous heat-fusible organic resin 2 directly thermally laminated on the outer surface of the lid 3
1 has a structure in which a large number of fine through holes 24 are uniformly formed in the heat-fusible organic resin 23 as shown in FIG.
As shown in FIG. 14, the porous heat-fusible organic resin 22 directly thermally laminated on the inner surface of the lid 3 has a large number of fine non-through holes 25 uniformly formed in the heat-fusible organic resin 23. It has a perforated structure. The porous heat-fusible organic resin film 22 is directly thermally laminated such that the bottom portion (remaining thin film) of the non-through hole 25 is located on the inner surface side of the lid 3.

The pull-top mechanism is formed on the lid 3 and has the structure shown in FIGS. 1 and 3 described above.

The inner surface of the lid 3 is not limited to the structure shown in FIG. 14, but may have the following structure.

For example, as shown in FIG. 15, the thermally fusible organic resin film 26 having a thickness of 5 to 15 μm described in (1) of the first embodiment is directly thermally laminated on the inner surface of the lid 3. Good.

As shown in FIG. 16, the organic resin film 27 having a thickness of 5 to 12 μm described in (3) of the first embodiment is provided on the inner surface of the lid 3 via the hot melt resin layer (adhesive layer) 28. May be subjected to thermal lamination.

As shown in FIG. 17, a porous organic resin film (for example, organic resin film 29) having a large number of at least one hole selected from the fine through holes and the non-through holes described in (4) of the first embodiment. Alternatively, a porous organic resin film 31) having a large number of fine through holes 30 may be thermally laminated on the inner surface of the lid 3 via a hot melt resin layer (adhesive layer) 28.

The pull-top can according to the second embodiment described above has a can body with an open top and at least an inner surface laminated with an organic resin film, and is attached to the opening of the can body by caulking, for example. An aluminum lid having a mechanism. The lid is directly thermally laminated with a porous heat-fusible organic resin film having a large number of at least one hole selected from fine through holes and non-through holes on its outer surface.

In the pull-top can having such a structure, as shown in FIGS. 9 and 10 described above, the can main body 1 is held by one hand (not shown), and the other hand (not shown) is used. When the tab 10 of the pull-top mechanism 6 is erected vertically with a finger, the end of the dove 10 near the joint of the pin 9 is located inside the horseshoe-shaped opening 8 as shown in FIG. The surface of the part is pressed toward the can body 1 side. When the tab end is pressed, a porous heat-fusible organic resin film 21 having a large number of through holes 24 and easily tearable is directly laminated on the outer surface of the lid 3 as shown in FIGS. Have been. For this reason, notches are formed not only in the lid 3 but also in the porous heat-fusible organic resin 21 along the groove of the horseshoe-shaped opening portion,
As shown in FIGS. 9 and 10 described above, the lid 3 inside the horseshoe-shaped opening 8 is bent toward the inside of the can body 1 and opened. At this time, the lid 3 can be opened without any hair ring called an angel mark on the outside of the lid 3.

More specifically, when the end of the tub 10 presses the lid 3 inside the horseshoe-shaped opening 8, a porous heat-fusible organic resin directly thermally laminated on the outer surface of the lid 3. A large number of fine through holes 24 are formed in the film 21, and these through holes 24 act as tearing starting points (rupture starting points). Therefore, FIG.
8, as shown in FIG. 19, a cut is formed along the groove of the unsealing portion 8 located around the pressing portion, and at the same time, the porous heat-fusible organic resin film 21 directly thermally laminated Cuts are formed along the multiple through holes 24. Further, when the tab 10 is vertically erected, the pressing stroke on the lid 3 located inside the horseshoe-shaped opening 8 becomes longer. For this reason, the groove of the opening portion 8 is cut long together with the porous heat-fusible organic resin film 21, and the horseshoe-shaped opening portion 8 is cut.
The inner lid 3 is bent toward the inside of the can body 1 and can be opened without any hair ring called an angel mark on the outside of the lid 3.

By the way, the present inventor has studied the mechanism of the occurrence of hairing in the pull-top type can disclosed in JP-A-11-171179 described in the prior art. As a result, when a porous organic resin film is laminated on the outer surface of the lid of the pull-top can, a heat-fusible adhesive (for example, a two-component polyester polyurethane-based adhesive) is co-extruded onto the porous organic resin film. The laminated film is placed on the outer surface of the lid so that the adhesive layer is positioned on the lid side and is subjected to thermal lamination. Therefore, the thickness of the adhesive layer is not controlled, and the laminated film is partially improper. It has been clarified that the uniformity is obtained and that the stretchability of the adhesive layer is higher than that of the porous organic resin film. That is, when the lid portion located inside the horseshoe-shaped opening portion is bent toward the inside of the can main body at the time of pressing the above-described tab end portion, although the porous organic resin film is easily broken, This causes a layer separation failure at the boundary of the adhesive layer (particularly at the position of the adhesive layer having a small thickness) so that the adhesive layer extends without following the breakage of the porous organic resin film. It has been found that hairing called the angel mark occurs at the position (1).

Thus, by directly laminating a porous heat-fusible organic resin film 21 on the outer surface of the lid 3, the aforementioned horseshoe-shaped opening portion is pressed by pressing the end of the tab 10. 8, when the lid 3 is bent toward the inside of the can body 1 and opened, the porous heat-fusible organic resin film 21 undergoes layer separation near the interface of the outer surface of the lid 3. A hair ring called an angel mark is generated on the outer surface of the lid 3 as in the case where an adhesive layer is used, which is easily broken by using the large number of through holes 24 as break points without breaking. Can be opened without.

In particular, the porous heat-fusible organic resin film has a thickness of 5 to 30 μm, and has a thickness of 5 to 100 μm.
A highly rigid amorphous unstretched polyethylene terephthalate film in which at least one hole selected from a fine through hole having an average opening diameter of μm and a non-through hole is opened at a density of 500 / cm ² or more. By using such a porous heat-fusible organic resin film, it is possible to more reliably prevent the occurrence of hair ringing on the outer surface side of the lid when the pull-top mechanism is opened.

Further, by using a porous heat-fusible organic resin film 21 having a large number of fine through-holes 24 formed therein, the direct thermal lamination on the outer surface of the lid 3 allows the The air remaining at the interface of the heat-fusible organic resin film 21 can escape from the large number of through holes 24 to remove the air. As a result, the outer surface of the lid 3 and the porous heat-fusible organic resin film 21 can be uniformly and uniformly laminated, and the breakability of the porous heat-fusible organic resin film 21 can be further stabilized. Becomes possible.

Further, by directly thermally laminating a porous heat-sealable organic resin film 22 similar to the outer surface on the inner surface of the lid 3, the openability of the pull-top mechanism can be maintained without impairing the openability. It is possible to prevent the occurrence of hairing called feathering on the inner surface side of the lid 3. In addition, as shown in FIGS. 15 to 17 described above, even in a structure in which an easily breakable organic resin film is laminated on the inner surface of the lid 3, when the pull-top mechanism is opened, the lid can be opened without impairing the opening property. 3 It is possible to prevent the occurrence of hair ring called feathering on the inner surface side.

Therefore, the pull-top type can of the second embodiment is provided with a porous heat-fusible organic resin film directly thermally laminated on the outer surface of the lid without impairing the openability of the pull-top mechanism and the appearance. It can be easily opened without generating a hair ring called an angel mark that impairs. In addition, the outer surface of the lid can be protected from the outside by directly thermally laminating the outer surface of the lid with a porous heat-fusible organic resin film.

Further, a porous heat-fusible organic resin film is directly laminated on the inner surface of the can body by thermal lamination (or FIG. 1).
5 to 17) by laminating the easily breakable organic resin film shown in FIG. 17 to prevent oxidation or the like caused by the contents in the can coming into direct contact with the material such as aluminum of the can body and the lid. Quality can be maintained for a long time.

Further, since the heat-fusible organic resin film on the outer surface and the inner surface of the lid can be coated by a laminating method, a washing step requiring an enormous amount of water after coating as in the conventional baking coating is omitted. As a result, running costs can be significantly reduced.

(Third Embodiment; Method for Manufacturing Pull Top Can) First, a hot melt resin is coated on one surface of an aluminum thin plate to form a hot melt resin layer. Subsequently, a thin organic resin film having a thickness of 5 to 12 μm is thermally laminated on the hot melt resin layer. Subsequently, the aluminum thin plate on which the organic resin film is laminated is formed into a circular outer shape by, for example, punching, and is pressed from the coating surface (outer surface) side of the organic resin film to form a horseshoe-shaped groove in the aluminum thin plate. After forming an opening portion and the like, a lid is manufactured by forming a pull-top mechanism by pin-joining a tab to the coating surface side of the organic resin film.

Next, a lid having the above-mentioned pull-top mechanism is attached to an upper opening of a can body made of, for example, aluminum or steel having an organic resin film laminated on its inner surface, for example, by caulking to produce a pull-top can.

The aluminum thin plate is usually 280
It has a thickness of 340 μm.

The hot melt resin desirably has high rigidity in a state where the hot melt resin layer is formed, and for example, a polyester hot melt resin or a nylon hot melt resin can be used. In particular, from the viewpoint of preventing layer separation destruction at the boundary between the hot melt resin layer and the porous organic resin film at the time of opening by the pull-top mechanism, it is preferable to use the same resin material as the hot melt resin and the organic resin film. preferable.

The hot-melt resin layer has a thickness of 2 to 5 μm mainly from the viewpoint of tearability (especially prevention of generation of hair).
m.

As a means for coating the hot melt resin, for example, a hot melt resin is dissolved in a liquid medium such as an organic solvent or water, and this solution is applied to a thin aluminum plate by dipping, spraying, or roll coating. Alternatively, a method in which the hot melt resin is melted and the melt is coated on an aluminum thin plate by a roll coater method or the like can be employed. Usually, a hot melt resin layer is formed by performing a drying treatment after coating with such a hot melt resin.

As the organic resin film, for example, a polyester film such as a polyethylene terephthalate film, nylon, an oriented polypropylene film and the like can be used.

If the thickness of the organic resin film is less than 5 μm, it may be difficult to effectively protect the outer surface of the lid. On the other hand, when the thickness of the organic resin film is 12
If it exceeds μm, there is a possibility that the opening property by the above-mentioned pull-top mechanism is impaired.

As means for thermally laminating the organic resin film to the hot melt resin layer, for example, a hot roll method can be employed.

It is allowed to further laminate an easily breakable organic resin film described below on the surface of the aluminum thin plate which is on the inner surface side in the cover state. By laminating such an easily rupturable organic resin film on the surface of the aluminum thin plate on the inner surface side in the lid state, a lid body was prepared from this thin plate, and in a pull-top can manufactured by incorporating the same, It is possible to prevent the contents from directly contacting aluminum, which is the material of the lid, and to protect the contents.

(1) A thermally fusible organic resin film having a thickness of 5 to 15 μm is directly thermally laminated on the surface of the aluminum thin plate which is on the inner surface side in the cover state.

As the heat-fusible organic resin film, the same film as that laminated on the outer surface of the lid described in the first embodiment can be used.

(2) A porous heat-fusible organic resin film having a large number of at least one hole selected from fine through holes and non-through holes is directly formed on the surface of the aluminum thin plate which is the inner surface side in the state of the lid. Perform thermal lamination.

As the heat-fusible organic resin film,
Amorphous non-stretched polyethylene terephthalate film, non-stretched polypropylene film, ionomer resin film, etc. A density polyethylene film or the like can be used. In particular, a non-stretched PET film having good printability is preferable. In particular, an amorphous unstretched polyethylene terephthalate film having excellent adhesion to the inner surface of the lid and excellent tearing property upon opening is preferable.

The porous heat-fusible organic resin film has a thickness of 5 to 30 μm, more preferably 9 to 25 μm, for the same reason as described in (2) of the first embodiment. Is desirable.

The porous heat-fusible organic resin film is manufactured by making the heat-fusible organic resin film porous by a porous film manufacturing apparatus disclosed in Japanese Patent Publication No. 6-61859. .

The porous heat-fusible organic resin film has a thickness of 0.5 to 100 μm, more preferably 2 to 50 μm, for the same reason as described in (2) of the first embodiment.
At least one hole selected from through holes and non-through holes having an average opening diameter of μm is 500 holes / cm ² or more, more preferably 1000 holes / cm ^{2 to} 5000 holes / cm 2.
It is desirable that holes are formed at a density of In particular, from the viewpoint of protecting the contents in the can, it is preferable to use a porous heat-fusible organic resin film having a large number of non-through holes.

(3) A mode in which an organic resin film having a thickness of 5 to 12 μm is thermally laminated through an adhesive layer on the surface of the aluminum thin plate which is on the inner side in the state of the lid.

In the thermal laminating step, a hot melt resin layer (adhesive layer) is co-extruded onto the organic resin film to form a laminated film, and the laminated film is laminated on the surface of the aluminum thin plate. Thermal lamination is performed by arranging it so as to be located on the thin plate surface side. Further, a hot melt resin may be coated on the surface of the aluminum thin plate to form a hot melt resin layer, and then an organic resin film may be thermally laminated on the hot melt resin layer by a hot roll method or the like.

As the organic resin film, for example, a polyester film such as a polyethylene terephthalate film, a nylon film, an oriented polypropylene film and the like can be used.

The thickness of the organic resin film is specified for the same reason as described in (3) of the first embodiment.

As the hot melt resin, general ones applicable to foods can be used, and for example, polyester hot melt resins and nylon hot melt resins can be used. The thickness of the hot melt resin layer is preferably 2 to 5 μm from the viewpoint of tearability and protection of contents.

(4) A porous organic resin film having a large number of at least one hole selected from fine through-holes and non-through-holes is formed on the surface of the aluminum thin plate which is the inner surface side in the state of the lid via an adhesive layer. Perform thermal lamination.

In the thermal laminating step, a laminated film is formed by extruding a hot melt resin layer (adhesive layer) onto the porous organic resin film, and the laminated film is laminated on the surface of the aluminum thin plate with the hot melt resin. This is performed by arranging the layers so that the layers are located on the sheet surface side and performing thermal lamination. Alternatively, a hot melt resin layer may be formed by coating the surface of the aluminum thin plate with a hot melt resin, and then a porous organic resin film may be thermally laminated on the hot melt resin layer by a hot roll method or the like.

As the organic resin, for example, polyester such as polyethylene terephthalate, nylon, oriented polypropylene and the like can be used.

The above-mentioned porous organic resin film comprises
5 to 4 for the same reason as described in the embodiment (4).
It is desirable to have a thickness of 0 μm, more preferably 9-25 μm.

The porous organic resin film is formed of the first organic resin film.
For the same reason as described in the embodiment (4), 0.5
500 at least one hole (through-hole, non-through-hole or a mixture of through-holes and non-through-holes) selected from through-holes and non-through-holes having an average opening diameter of １００100 μm, more preferably 2 to 50 μm / Cm ² or more, more preferably 1000 holes / cm ^{2 to} 5000 holes / cm ² . The porous organic resin film having pores with such an average opening diameter and density has a tear strength sufficiently lower than that of the non-porous organic resin film, and has a higher tearability than the non-porous organic resin film. (Breakability).

As the hot melt resin, a general hot melt resin can be used, and for example, a polyester hot melt resin and a nylon hot melt resin can be used. The thickness of the hot melt resin layer is preferably 2 to 5 μm from the viewpoint of tearability and protection of contents.

(5) An organic resin film is thermally laminated directly or via an adhesive layer on the surface of the aluminum thin plate which is the inner surface side in the state of the lid, and a large number of fine non-through holes are formed in the organic resin film. I do. When an organic resin film is laminated via an adhesive layer, it is permissible to form through holes or holes in which through holes and non-through holes are mixed in the organic resin film.

Examples of the organic resin film directly thermally laminated on the surface of the aluminum thin plate include Ea
Amorphous unstretched polyethylene terephthalate film such as Okura Kogyo Co., Ltd.'s Oster Copolyester film, which is an inflation film of stman's Auster copolyester (amorphous polyester), unstretched polypropylene film, ionomer resin film,
A heat-fusible organic resin film such as a low-density polyethylene film can be used. It is desirable that this heat-fusible organic resin film has a thickness of 5 to 40 μm, more preferably 9 to 25 μm.

The organic resin thermally laminated on the surface of the aluminum thin plate via an adhesive layer includes:
For example, polyester such as polyethylene terephthalate, nylon, oriented polypropylene and the like can be used. This organic resin film preferably has a thickness of 5 to 30 μm, more preferably 9 to 25 μm.

In the thermal laminating step of laminating the organic resin film via an adhesive layer, a hot melt resin layer (adhesive layer) is co-extruded on the organic resin film to form a laminated film. The hot-melt resin layer is arranged on the surface of the thin plate so as to be positioned on the thin-plate surface side, and is subjected to thermal lamination. Further, a hot melt resin may be coated on the surface of the aluminum thin plate to form a hot melt resin layer, and then an organic resin film may be thermally laminated on the hot melt resin layer by a hot roll method or the like.

As the hot melt resin, general ones applicable to foods can be used, and for example, polyester hot melt resins and nylon hot melt resins can be used. The thickness of the hot melt resin layer is preferably 2 to 5 μm from the viewpoint of tearability and protection of contents.

The step of forming a large number of non-through holes in the heat-fusible organic resin film (or the organic resin film) may be performed, for example, by using a porous film manufacturing apparatus disclosed in Japanese Patent Publication No. 6-61859. Can be. When drilling this non-through hole, 0.5 to 100 μm,
More preferably, the number of fine non-through holes having an average opening diameter of 2 to 50 μm is 500 or more / cm ² , more preferably 10 / cm ² or more.
00 pieces / cm ^2, it is desirable to opening at a density of 5000 cells / cm ^2. A porous heat-fusible organic resin film (or organic resin film) having pores with such an average opening diameter and density has a tear strength sufficiently lower than that of a non-porous organic resin film, and a non-porous organic resin film. It shows higher tearing property (breakability) than the organic resin film in the hole state.

The can body is made of, for example, steel or aluminum.

Next, a method for manufacturing a pull-top can according to the third embodiment will be described more specifically with reference to the drawings.

First, as shown in FIG. 20A, a hot melt resin melt is roll-coated on both surfaces of an aluminum thin plate 41 and dried to form a hot melt resin layer. Subsequently, as shown in FIG. 20B, an organic resin film having a thickness of 5 to 12 μm
b is hot-pressed on the hot melt resin layers 42 on both surfaces of the aluminum thin plate 41, respectively, and thermally laminated.

Next, organic resin films 43a,
43b is punched out in a circular shape from the aluminum thin plate 41 thermally laminated, and pressed from the organic resin film 43a side (the outer surface in the state of the lid) to form the thin plate 41 and the organic resin films 43 on both surfaces.
After forming an opening portion or the like formed of a horseshoe-shaped groove in each of a and 43b, a lid 52 having a pull-top mechanism 51 shown in FIG. Made. As shown in FIG. 21, the pull-top mechanism 51 has a shoe-shaped depression 53 formed on the outer surface of the lid 52 by pressing, and is formed by pressing on a curved surface area of the depression 53, and is opened. Opening portion 5 consisting of a horseshoe-shaped groove where a cut is formed
4 and an elongated tab 56 having two holes that are joined to a recess 53 on the opposite side of the unsealing portion 54 by a pin 55 located near the center, and that abut on the surface of the recess 53. ing.

Next, the lid 52 having the pull-top mechanism 51 is caulked and joined to the upper opening of the can body 58 having the organic resin film 57 laminated on the inner surface (the outer surface as necessary) of FIGS. The pull-top can 59 for soft drink shown in FIG. Here, FIG. 22 is a top view of the pull-top can, FIG. 23 is a front view of the pull-top can of FIG. 22, FIG. 24 is a cross-sectional view of the shoulder of the pull-top can of FIG. It is an expanded sectional view of a body.

The step of laminating an organic resin film on both sides of the aluminum thin plate 41 is the same as that of FIG.
The method is not limited to the steps 0 (a) and (b), and the organic resin film may be laminated by the following method, for example.

For example, as shown in FIG. 26A, one surface of the aluminum thin plate 41 (the surface which becomes the outer surface in the state of the lid)
Then, a hot melt resin melt is roll-coated and dried to form a hot melt resin layer 42. Subsequently, as shown in FIG.
An organic resin film 43 having a thickness of 2 μm is hot-pressed on the hot melt resin layer 42 on one side of the aluminum thin plate 41 and thermally laminated.
The thin heat-fusible organic resin film 44 having a thickness of 5 to 15 μm described in the above (1) is directly thermally laminated on the surface on the opposite side (the surface which becomes the inner surface in the state of the lid) by hot pressing. At this time, even if the heat-fusible organic resin film 44 is thermally laminated first, the organic resin film 4
3 and the heat-fusible organic resin film 44 may be simultaneously thermally laminated.

As shown in FIG. 27A, one side of the aluminum thin plate 41 (the surface which becomes the outer surface in the state of the lid) is roll-coated with a hot melt resin melt and dried to form a hot melt resin layer 42. To form Subsequently, as shown in FIG. 27B, the thin organic resin film 43 is placed on the hot melt resin layer 4 on one side of the aluminum thin plate 41.
2 and then subjected to thermal laminating, and the surface opposite to the aluminum thin plate 41 (the surface that becomes the inner surface in the state of the lid) is selected from the fine through holes and the non-through holes described in (2) above. A porous heat-sealable organic resin film having a large number of at least one hole (for example, a porous heat-sealable organic resin film in which a large number of fine non-through holes 36 are formed in a heat-sealable organic resin film 45) 47) is directly thermally laminated by a hot press. At this time, the porous heat-fusible organic resin film 47 may be thermally laminated first, or the organic resin film 43 and the porous heat-fusible organic resin film 47 may be simultaneously thermally laminated.

As shown in FIG. 28A, a hot-melt resin melt is roll-coated on both sides of an aluminum thin plate 41 and dried to form a hot-melt resin layer. Subsequently, as shown in FIG. 28 (b), the thin organic resin film 43 is coated with the hot melt resin layer 4 on one surface of the aluminum thin plate 41 (the surface which becomes the outer surface in the state of the lid).
2 and hot-laminated, and then the hot melt resin layer 42 on the opposite side of the aluminum thin plate 41 (the surface that becomes the inner surface in the state of the lid) has the fine through-holes described in (4) above. A porous organic resin film having a large number of at least one hole selected from non-through holes (for example, a porous organic resin film 50 having a large number of fine through holes 49 formed in an organic resin film 48) is thermally laminated by hot pressing. . At this time, the porous organic resin film 50 may be thermally laminated first, or the organic resin film 43 and the porous organic resin film 50 may be simultaneously thermally laminated.

Further, a hot melt resin melt is roll-coated on one side of the aluminum thin plate (the surface that becomes the outer surface in the state of the lid) and dried to form a hot melt resin layer. Subsequently, a thin organic resin film is hot-pressed on the hot melt resin layer on one side of the aluminum sheet and thermally laminated, and then heat-sealed to the opposite side of the aluminum sheet (the surface that becomes the inner surface in the state of the lid). The organic resin film is directly thermally laminated by hot pressing. Thereafter, the heat-fusible organic resin film is made porous by a porous film manufacturing apparatus disclosed in Japanese Patent Publication No. 6-61859, whereby the porous structure having the structure shown in FIG. A heat-fusible organic resin film is formed on the inner surface of the aluminum thin plate in the state of the lid.

Further, a hot melt resin melt is roll-coated on both sides of the aluminum thin plate and dried to form a hot melt resin layer. Subsequently, the organic resin film is hot-pressed on the hot melt resin layer of the aluminum thin plate, respectively, and thermally laminated. Thereafter, the organic resin film, which is the inner surface side in the state of the lid, is made porous by the porous film manufacturing apparatus disclosed in Japanese Patent Publication No. 6-61859, and this is shown in FIG. A porous organic resin film having a structure is formed on an inner surface in a state of the lid of the aluminum thin plate.

In the method for manufacturing a pull-top can according to the third embodiment described above, a can body having an opening at the top and an inner surface laminated with an organic resin film is attached to the opening of the can body by, for example, caulking. In producing a pull-top can having an aluminum lid having a pull-top mechanism, a hot-melt resin layer is formed by coating a hot-melt resin on one surface of an aluminum thin plate, and the hot-melt resin layer has a thickness of 5 to 5 mm. After the organic resin film having a thickness of 12 μm is thermally laminated, the outer shape processing and the formation of the pull-top mechanism are performed, thereby providing a step of producing a lid in which the organic resin film is located on the outer surface side.

In the pull-top type can manufactured by such a method, as shown in FIGS. 29 and 30, the can main body 1 is held by one hand (not shown), and the other hand (not shown). When the tab 56 of the pull-top mechanism 51 is vertically erected by the finger of the user, as shown in FIG.
The end of the dove 56 near the joint of the cover 52 presses the surface of the lid 52 located inside the horseshoe-shaped opening portion 54 toward the can main body 58 side. When pressing the end of the tab 56,
On the outer surface of the lid 52, a hot melt resin layer 42 in which a thin organic resin film 43A having a thickness of 5 to 12 μm is formed in advance.
Through thermal lamination. For this reason, notches are formed not only in the lid 52 but also in the organic resin 43 along the groove of the horseshoe-shaped opening portion 54, and FIG.
9. As shown in FIG. 30, the lid 52 inside the horseshoe-shaped opening portion 54 is bent toward the inside of the can main body 58 and opened. At this time, the lid 52 can be opened without any hair ring called an angel mark on the outside of the lid 52.

More specifically, when the end of the tab 56 presses the lid 52 inside the horseshoe-shaped opening 54, the lid is thermally laminated via the hot melt resin layer 42 formed on the outer surface of the lid 52 in advance. Organic resin film 43
Since a is as thin as 5 to 12 μm in thickness, a cut is formed along the groove of the unsealing portion 54 located around the pressing portion at the initial stage of pressing as shown in FIGS. Cuts are formed in the hot melt resin layer 42 and the organic resin film 43a thermally laminated on the hot melt resin layer 42 along the groove of the opening portion 54. Further, when the tab 56 is vertically erected, the pressing stroke on the lid 52 located inside the horseshoe-shaped opening portion 54 becomes longer. For this reason, the groove of the opening portion 54 is cut long together with the organic resin film 43a, and the lid 52 portion inside the horseshoe-shaped opening portion 54 is bent toward the inside of the can main body 58 so that the lid portion is bent. 52
Can be opened without any hair ring called an angel mark on the outside of the box.

By the way, the present inventor has studied the mechanism of the occurrence of hairing in the pull-top can described in Japanese Patent Application Laid-Open No. 11-171179 described in the prior art. As a result, when a porous organic resin film is laminated on the outer surface of the lid of the pull-top can, a heat-fusible adhesive (for example, a two-component polyester polyurethane-based adhesive) is co-extruded onto the porous organic resin film. The laminated film is placed on the outer surface of the lid so that the adhesive layer is positioned on the lid side and is subjected to thermal lamination. Therefore, the thickness of the adhesive layer is not controlled, and the laminated film is partially improper. It has been clarified that the uniformity is obtained and that the stretchability of the adhesive layer is higher than that of the porous organic resin film. That is, when the lid portion located inside the horseshoe-shaped opening portion is bent toward the inside of the can main body at the time of pressing the tab end described above, the porous organic resin film is easily broken. This causes a layer separation failure at the boundary of the adhesive layer (particularly at the position of the adhesive layer having a small thickness) so that the adhesive layer extends without following the breakage of the porous organic resin film. It has been found that hairing called the angel mark occurs at the position (1).

In view of the above, when manufacturing the lid, as shown in FIGS. 20A and 20B, one surface of the aluminum thin plate 41 as the lid material (the surface which becomes the outer surface in the lid state). ) Is coated with a hot melt resin to form a hot melt resin layer 42 having a uniform thickness, and the hot melt resin layer 42 is coated with an organic resin film 43a having a thickness of 5 to 12 μm.
When the lid 52 located inside the horseshoe-shaped opening portion 54 is bent toward the inside of the can body 58 when the end of the tab 56 is pressed, the hot-melt resin The layer separation destruction of the hot melt resin layer 52 at the boundary of the lid 52 due to the uneven thickness of the layer 42 can be prevented. Therefore, the organic resin film 43a and the hot melt resin layer 42
Are easily broken and can be opened without any hair ring called an angel mark on the outer surface of the lid 52.

Further, an organic resin film 43b having a thickness of 5 to 12 μm is thermally laminated on a surface opposite to the aluminum thin plate 41 (a surface which becomes an inner surface in a state of the lid) via a hot melt resin layer 42 formed in advance. By
At the time of opening the pull-top mechanism 56 of the lid 52 made of this thin plate, without impairing the openability thereof,
It is possible to prevent hairing called feathering from occurring on the inner surface side of the lid 52. 26 to FIG.
As shown in FIG. 28, an easily breakable organic resin film is laminated on the surface on the opposite side of the aluminum thin plate 41 (the surface that becomes the inner surface in the state of the lid), and the lid 5 made from this thin plate is laminated.
Also in 2, when opening the pull-top mechanism 56, it is possible to prevent the occurrence of hair ring called feathering on the inner surface side of the lid 52 without impairing the opening property.

Therefore, the pull-top type can manufactured by the method of the third embodiment is made of an organic resin film having a thickness of 5 to 12 μm, which is thermally laminated on the outer surface of the lid via a hot melt resin layer previously formed. The pull-top mechanism can be easily opened without obstructing the openability of the pull-top mechanism and without causing hair ring called angel mark which impairs the appearance. In addition, by thermally laminating an organic resin film on the outer surface of the lid via a hot melt resin layer, the outer surface of the lid can be protected from the outside.

Also, by laminating an organic resin film on the inner surface of the can body by thermal lamination and laminating an easily breakable organic resin film on the surface of the aluminum thin plate which is the inner surface in the lid state when the lid is made, The content in the can is prevented from being oxidized due to the direct contact with the material such as aluminum of the can body and the lid, and the quality can be maintained for a long time.

Further, at the time of producing the lid, an organic resin film was thermally laminated on one side of the aluminum thin plate (the surface which becomes the outer surface in the state of the lid) via a hot melt resin layer, and the surface opposite to the aluminum thin plate (the lid was closed). Laminating an easily breakable organic resin film on the surface that becomes the inner surface in the body state), that is, the organic resin film can be coated on both sides of the aluminum thin plate by the lamination method, so that a huge amount of water is applied after painting like the conventional baking coating The required cleaning step can be omitted, and the running cost can be greatly reduced.

(Fourth Embodiment; Method for Manufacturing Pull Top Can) First, a hot melt resin is coated on one surface of an aluminum thin plate to form a hot melt resin layer. Subsequently, a porous organic resin film having at least one hole selected from many fine non-through holes and through holes is thermally laminated on the hot melt resin layer. Subsequently, the aluminum thin plate on which the porous organic resin film is laminated is externally processed into a circular shape by, for example, punching, and is pressed from the coating surface side of the porous organic resin film to form a thin aluminum plate through a horseshoe-shaped groove. After forming the unsealing portion or the like, a lid is manufactured by forming a pull-top mechanism by pin-joining a tab to the covering surface of the porous organic resin film.

Next, the lid having the above-mentioned pull-top mechanism is attached to the upper opening of the can body having the organic resin film laminated on the inner surface (and the outer surface as necessary) by, for example, caulking and attached, whereby a pull-top can is manufactured. I do.

The aluminum thin plate is usually 280
It has a thickness of 340 μm.

The hot melt resin desirably has high rigidity in a state where the hot melt resin layer is formed, and for example, a polyester hot melt resin and a nylon hot melt resin can be used. Particularly, from the viewpoint of preventing layer separation destruction at the boundary between the hot melt resin layer and the porous organic resin film at the time of opening by the pull-top mechanism, use the same resin material as the hot melt resin and the porous organic resin film. Is preferred.

The hot-melt resin layer has a thickness of 2 to 5 μm mainly from the viewpoint of tearing property (especially prevention of hair ringing).
m.

As a means for coating the hot melt resin, for example, a hot melt resin is dissolved in a liquid medium such as an organic solvent or water, and this solution is applied to an aluminum thin plate by dipping, spraying, or a roll coater method. Alternatively, a method may be employed in which the hot melt resin is melted, and the melt is coated on a thin aluminum plate by a roll coater method or the like. Usually, a hot melt resin layer is formed by performing a drying treatment after coating with such a hot melt resin.

The porous organic resin film is manufactured by making the organic resin film porous using a porous film manufacturing apparatus disclosed in Japanese Patent Publication No. 6-61859.

As the organic resin film to be made porous, for example, a polyester film such as a polyethylene terephthalate film, nylon, an oriented polypropylene film and the like can be used.

The porous organic resin film has a thickness of 5 to 40.
It preferably has a thickness of μm. If the thickness of the porous organic resin film is less than 5 μm, it may be difficult to effectively protect the outer surface of the lid. On the other hand, if the thickness of the organic resin film exceeds 40 μm, even if many fine holes are formed, the tearing property may be reduced and the opening property by the above-mentioned pull-top mechanism may be impaired. More preferably, the thickness of the porous organic resin film is 9 to 25 μm.
It is.

The porous organic resin film has a thickness of from 0.5 to
It is desirable that at least one hole selected from a non-through hole and a through hole having an average opening diameter of 100 μm is formed at a density of 500 holes / cm ² or more. The porous organic resin film having pores with such an average opening diameter and density has a tear strength sufficiently lower than that of the non-porous organic resin film, and has a higher tearability than the non-porous organic resin film. (Breakability).

The reason why the average opening diameter of the pores of the porous organic resin film is specified is as follows. If the average opening diameter is less than 0.5 μm, it may be difficult to easily open the lid on which the porous organic resin film is laminated by the pull-top mechanism. On the other hand, when the average opening diameter exceeds 100 μm, moisture and the like easily penetrate into the porous organic resin film on the outer surface of the lid, causing corrosion at the rib portion with the main body to effectively protect the lid. May be difficult. More preferably, the average opening diameter of the holes is 2 to 50 μm.

The pore density of the porous organic resin film is defined for the following reasons. If the density is less than 500 / cm ² , it will be difficult to laminate a porous organic resin film having high tearability on the outer surface of the lid. The upper limit of the density is not particularly limited. However, through-holes having a density of 25,000 / cm ² can be formed by one treatment using the above-described porous film manufacturing apparatus. More preferably, the density of the holes is from 1000 holes / cm ^{2 to} 5000 holes / cm ² .

As a means for thermally laminating the porous organic resin film on the hot melt resin layer, for example, a hot roll method or the like can be adopted.

The main body of the can is made of, for example, steel or aluminum.

It is permissible to further laminate an easily breakable organic resin film by the method (1) to (5) described in the third embodiment on the surface of the aluminum thin plate which is on the inner surface side in the cover state. I do. By laminating such an easily breakable organic resin film on the surface of the aluminum thin plate on the inner surface side in the lid state,
A lid is made from this thin plate, and in a pull-top can manufactured by incorporating the same, the content can be prevented from directly contacting aluminum, which is a material of the lid, and the content can be protected. .

Next, a method of manufacturing a pull-top can according to the fourth embodiment will be described more specifically with reference to the drawings.

First, as shown in FIG. 33 (a), a hot melt resin melt is roll-coated on both sides of an aluminum thin plate 61 and dried to form a hot melt resin layer 62. Subsequently, as shown in FIG. 33B, a porous organic resin film having a large number of at least one hole selected from fine non-through holes and through holes in the organic resin film (for example, a large number of fine Two porous organic resin films 6 each having a through hole 64 formed therein.
5, 66) are prepared, and the porous organic resin films 65, 66 are hot-pressed on the hot melt resin layers 62 on both surfaces of the aluminum thin plate 61, respectively, and thermally laminated.

Next, the porous organic resin film 6 was formed on both sides.
5 and 66 are punched in a circular shape from the aluminum thin plate 61 on which the thermal lamination is performed, and are pressed from the side of the porous organic resin film 65 (the side that becomes the outer surface in the state of the lid) to form the porous plate of the thin plate 61 and both sides. After forming an opening or the like formed of a horseshoe-shaped groove in the porous organic resin films 65 and 66, the covering surface (outer surface) of the organic resin film 65 is formed.
A lid 52 having a pull-top mechanism 51 shown in FIG. As shown in FIG. 34, the pull-top mechanism 51 includes a shoe-shaped recess 53 formed on the outer surface of the lid 52 by pressing.
And an opening portion 54 formed of a horseshoe-shaped groove formed by pressing in the curved surface region of the recess portion 53 and having a notch formed at the time of opening. Elongate tab 5 having two holes that are joined by a pin 55 and that abut against the surface of the recess 53.
6 is comprised.

Next, the lid 52 having the pull-top mechanism 51 is swaged to the upper opening of the can body 58 in which the organic resin film 57 is laminated on the inner surface (the outer surface if necessary) in the same manner as in the third embodiment. By joining, a pull-top can 59 for soft drink shown in FIGS. 35 and 36 is manufactured. FIG. 35 is a sectional view of a shoulder of the pull-top can, and FIG. 36 is an enlarged sectional view of the lid of FIG.

The step of laminating an organic resin film on both sides of the aluminum thin plate 61 is performed in the same manner as in FIG.
The process is not limited to the steps 3 (a) and (b), and the organic resin film may be laminated by the following method, for example.

For example, as shown in FIG. 37A, one surface of the aluminum thin plate 61 (the surface which becomes the outer surface in the state of the lid)
Then, a hot melt resin melt is roll-coated and dried to form a hot melt resin layer 62. Subsequently, as shown in FIG. 37 (b), the porous organic resin film 65 described above is hot-pressed on the hot melt resin layer 62 on one side of the aluminum thin plate 41 and thermally laminated. (The surface which becomes the inner surface in the state of the lid) of the third embodiment (1)
The heat-fusible organic resin film 67 having a thickness of 5 to 15 μm described in (1) is directly thermally laminated by a hot press.
At this time, the heat-fusible organic resin film 67 may be thermally laminated first, or the porous organic resin film 65 and the heat-fusible organic resin film 67 may be simultaneously thermally laminated.

As shown in FIG. 38 (a), one side of the aluminum thin plate 61 (the surface which becomes the outer surface in the state of the lid) is roll-coated with a hot melt resin melt and dried to form a hot melt resin layer 62. To form Subsequently, as shown in FIG. 38 (b), the porous organic resin film 65 is hot-pressed on the hot melt resin layer 62 on one side of the aluminum thin plate 61 to be thermally laminated, and then, on the opposite side of the aluminum thin plate 61. A porous heat-fusing property having a large number of at least one hole selected from the fine through holes and the non-through holes described in (2) of the third embodiment on the surface (the surface that becomes the inner surface in the state of the lid) An organic resin film (for example, a porous heat-fusible organic resin film 70 in which a number of fine non-through holes 69 are formed in the heat-fusible organic resin film 68) is directly thermally laminated by hot pressing. At this time, even if the porous heat-fusible organic resin film 70 is thermally laminated first, the porous heat-fusible organic resin film 7
0 may be thermally laminated at the same time.

As shown in FIG. 39 (a), a hot melt resin melt is roll-coated on both sides of an aluminum thin plate 61 and dried to form a hot melt resin layer 62. Subsequently, as shown in FIG. 39 (b), the porous organic resin film 65 described above is hot-pressed on the hot melt resin layer 62 on one side of the aluminum thin plate 61 (the outer surface in the state of the lid). After laminating, the organic resin film 7 described in (3) of the third embodiment is applied to the hot melt resin layer 62 on the surface on the opposite side of the aluminum thin plate 61 (the surface that becomes the inner surface in the state of the lid).
1 is thermally laminated by a hot press. At this time,
The organic resin film 71 may be thermally laminated first, or the porous organic resin film 65 and the organic resin film 71 may be simultaneously thermally laminated.

Also, a hot melt resin melt is roll-coated on one side of the thin aluminum plate (the surface that becomes the outer surface in the state of the lid) and dried to form a hot melt resin layer. Subsequently, after the porous organic resin film is hot-pressed on the hot melt resin layer on one surface of the aluminum thin plate and thermally laminated, the surface on the opposite side of the aluminum thin plate (the surface which becomes the inner surface in the state of the lid) is heated. The fusible organic resin film is directly thermally laminated by a hot press. Thereafter, the heat-fusible organic resin film is made porous by using a porous film manufacturing apparatus disclosed in Japanese Patent Publication No. 6-61859.
A porous heat-fusible organic resin film having the structure shown in FIG. 8B is formed on the inner surface of the aluminum thin plate in the state of the lid.

Further, a hot melt resin melt is roll-coated on both sides of the aluminum thin plate and dried to form a hot melt resin layer. Subsequently, the porous organic resin film and the organic resin film are respectively hot-pressed on the hot melt resin layer of the aluminum thin plate and thermally laminated. After this, 6-6
No. 1859, the porous organic resin film having the structure shown in FIG. 33 (b) described above is made porous by making the organic resin film on the inner surface side in the state of the lid by the porous film manufacturing apparatus disclosed in Japanese Patent No. 1859. Is formed on an inner surface in the state of the lid of the aluminum thin plate.

In the method of manufacturing a pull-top can according to the fourth embodiment described above, a can body having an upper opening and an inner surface laminated with an organic resin film is attached to the opening of the can body by, for example, caulking. In manufacturing a pull-top can having an aluminum lid having a pull-top mechanism, a hot-melt resin is coated on one side of an aluminum thin plate to form a hot-melt resin layer. The method includes a step of thermally laminating a porous organic resin film having at least one hole selected from a non-through hole and a through hole, and then performing outer shape processing and forming the pull-top mechanism to produce a lid.

In the pull-top can manufactured by such a method, as shown in FIGS. 29 and 30, the can main body is held by one hand (not shown), and the other hand (not shown) is used. The tab 56 of the pull-top mechanism 51 is
29, the end of the dove 56 near the joint of the pin 55 is positioned on the inside of the horseshoe-shaped opening portion 54 as shown in FIG. Press toward 58 side. When the end of the tab 56 is pressed, as shown in FIGS.
For example, a porous organic resin film 65 having a large number of through holes 64 and easily tearable is thermally laminated on the two outer surfaces via a hot melt resin layer 62 formed in advance.
For this reason, notches are formed along the grooves of the horseshoe-shaped opening portion 54 not only in the lid 52 but also in the porous organic resin film 65, and as shown in FIGS. The lid 52 inside the portion 54 is the can body 5
8 is folded inward and opened. At this time,
The lid 52 can be opened without any hair ring called an angel mark on the outside of the lid 52.

More specifically, when the end of the tab 56 presses the lid 52 inside the horseshoe-shaped opening 54, the lid 52 is thermally laminated via the hot melt resin layer 62 formed on the outer surface of the lid 52 in advance. The porous organic resin film 65 has a large number of fine through-holes 64 formed therein, and these through-holes 64 act as tearing starting points (rupture starting points). Therefore, in the initial stage of the pressing, a cut is formed along the groove of the unsealing portion 54 located around the pressing portion as shown in FIGS.
Also, a cut is formed along the groove of the opening portion 54 in the porous organic resin film 65 thermally laminated thereon. Further, when the tab 56 is vertically erected, the pressing stroke on the lid 52 located inside the horseshoe-shaped opening portion 54 becomes longer. For this reason, the groove of the opening portion 54 is cut long together with the porous organic resin film 65, and the horseshoe-shaped opening portion 54
The inner lid 52 is bent toward the inside of the can body 58 and can be opened without any hair ring called an angel mark on the outside of the lid 52.

By the way, the present inventor has studied the mechanism of the occurrence of hairing in the pull-top can described in Japanese Patent Application Laid-Open No. 11-171179 described in the prior art. As a result, when a porous organic resin film is laminated on the outer surface of the lid of the pull-top can, a heat-fusible adhesive (for example, a two-component polyester polyurethane-based adhesive) is co-extruded onto the porous organic resin film. The laminated film is placed on the outer surface of the lid so that the adhesive layer is positioned on the lid side and is subjected to thermal lamination. Therefore, the thickness of the adhesive layer is not controlled, and the laminated film is partially improper. It has been clarified that the uniformity is obtained and that the stretchability of the adhesive layer is higher than that of the porous organic resin film. That is, when the lid portion located inside the horseshoe-shaped opening portion is bent toward the inside of the can main body at the time of pressing the tab end described above, the porous organic resin film is easily broken. This causes a layer separation failure at the boundary of the adhesive layer (particularly at the position of the adhesive layer having a small thickness) so that the adhesive layer extends without following the breakage of the porous organic resin film. It has been found that hairing called the angel mark occurs at the position (1).

For this reason, when manufacturing the lid, as shown in FIGS. 33 (a) and (b), one surface of the aluminum thin plate 61 (the surface which becomes the outer surface in the lid state) as shown in FIGS. ) Is coated with a hot-melt resin to form a hot-melt resin layer 62 having a uniform thickness, and a porous organic resin film 65 is thermally laminated on the hot-melt resin layer 62 to press the end of the tab 56 described above. In some cases, when the lid 52 located inside the horseshoe-shaped opening portion 54 is bent toward the inside of the can body 58, the lid 52 caused by the uneven thickness of the hot melt resin layer 62 is formed. At the boundary of the hot melt resin layer 62 can be prevented.

If a porous organic resin film having a large number of fine through-holes is used, thermal lamination on the hot-melt resin layer on the outer surface of the lid is possible.
Air remaining at the interface between the hot melt resin layer and the porous organic resin film can escape from the large number of through holes to release the air. As a result, since the porous organic resin film can be more uniformly and uniformly laminated on the hot melt resin layer, the lid positioned inside the horseshoe-shaped opening when the tab end is pressed as described above. When the portion is bent toward the inside of the can main body, layer separation destruction at the boundary between the hot melt resin layer and the porous organic resin film can be prevented.

Accordingly, both the porous organic resin film 65 and the hot melt resin layer 62 are easily broken, and can be opened without any hair ring called an angel mark on the outer surface of the lid 52.

Also, a porous organic resin film 66 is thermally laminated on a surface opposite to the aluminum thin plate 61 (a surface which becomes an inner surface in a state of a lid) via a hot melt resin layer 62 formed in advance. When opening the pull-top mechanism 56 of the lid 52 made of a thin plate, it is possible to prevent the occurrence of hair ring called feathering on the inner surface side of the lid 52 without impairing the opening property. As shown in FIGS. 37 to 39 described above, an easily breakable organic resin film was laminated on the surface on the opposite side of the aluminum thin plate 61 (the surface which becomes the inner surface in the state of the lid), and the aluminum thin plate 61 was manufactured from this thin plate. Also in the lid 52,
At the time of opening the pull-top mechanism 56, it is possible to prevent the occurrence of hair ring called feathering on the inner surface side of the lid 52 without impairing the opening property.

As described above, the pull-top type can manufactured by the method of the fourth embodiment is opened with the porous organic resin film thermally laminated via a hot-melt resin layer previously formed on the outer surface of the lid. It can be easily opened without impairing the properties and without causing hairing called an angel mark which impairs the appearance. In addition, since the porous organic resin film is thermally laminated on the outer surface of the lid via the hot melt resin layer, the outer surface of the lid can be protected from the outside.

Further, by laminating an organic resin film on the inner surface of the can body by thermal lamination and, when producing the lid, laminating an easily breakable organic resin film on the surface of the aluminum thin plate which is the inner surface in the lid state, The content in the can is prevented from being oxidized due to the direct contact with the material such as aluminum of the can body and the lid, and the quality can be maintained for a long time.

Further, a porous organic resin film was thermally laminated on one side of the aluminum thin plate (the surface that becomes the outer surface in the state of the lid) via a hot-melt resin layer when the lid was manufactured, and the surface on the opposite side of the aluminum thin plate was formed. (A surface that becomes the inner surface in the state of the lid) is laminated with an easily breakable organic resin film, that is, a porous organic resin film and an organic resin film can be coated on both sides of an aluminum thin plate by a laminating method. As described above, the washing step that requires an enormous amount of water after painting can be omitted, and the running cost can be greatly reduced.

(Fifth Embodiment; Method of Manufacturing Pull-Top Can) First, a heat-fusible organic resin film is directly thermally laminated on one surface of an aluminum thin plate, or an organic resin film is thermally laminated via an adhesive layer. . Subsequently, a large number of fine non-through holes are formed in the heat-fusible organic resin film or the organic resin film. Subsequently, this porous heat-fusible organic resin film (porous heat-fusible organic resin film) or an aluminum sheet laminated with an organic resin film (porous organic resin film) is formed into a circular shape by, for example, punching. After processing the outer shape and pressing the porous heat-fusible organic resin film or the porous organic resin film from the coating surface side to form an opening portion or the like formed of a horseshoe-shaped groove in the aluminum thin plate, A lid is manufactured by forming a pull-top mechanism by pin-joining a tab to a coating surface of a porous heat-fusible organic resin film or a porous organic resin film.

Next, a lid having the above-mentioned pull-top mechanism is caulked and joined to the upper opening of the can body having an organic resin film laminated on the inner surface to produce a pull-top can.

The aluminum thin plate is usually 280
It has a thickness of 340 μm.

Examples of the heat-fusible organic resin film include:
For example, an amorphous unstretched polyethylene terephthalate film such as Okura Kogyo Co., Ltd.'s Oster Copolyester film made from Eastman's Ooster Copolyester (amorphous polyester) as an inflation film, an unstretched polypropylene film, an ionomer resin film, A heat-fusible organic resin film such as a low-density polyethylene film can be used. In particular, an amorphous unstretched polyethylene terephthalate film having excellent adhesion to the outer surface of the lid and tearing property upon opening is preferable. The heat-fusible organic resin film preferably has a thickness of 5 to 40 μm, more preferably 9 to 25 μm. If the thickness of the heat-fusible organic resin film is less than 5 μm, it may be difficult to effectively protect the outer surface of the lid. On the other hand, when the thickness of the heat-fusible organic resin film is 4
If it exceeds 0 μm, it becomes difficult to impart sufficient tearability even if a large number of fine non-through holes are opened, and there is a possibility that the openability by the pull-top mechanism described above may be impaired.

As the organic resin film, for example, a polyester film such as polyethylene terephthalate, a nylon film, an oriented polypropylene film and the like can be used. This organic resin film is 5
It preferably has a thickness of 40 μm, more preferably 9-25 μm. The thickness of this organic resin film is 5μ
If it is less than m, it may be difficult to effectively protect the outer surface of the lid. On the other hand, if the thickness of the organic resin film exceeds 40 μm, it becomes difficult to impart sufficient tearability even when a large number of fine non-through holes are opened, and the opening property by the above-described pull-top mechanism is impaired. There is a fear.

In the thermal laminating step of laminating the organic resin film via an adhesive layer, a hot melt resin layer (adhesive layer) is co-extruded on the organic resin film to form a laminated film. The hot-melt resin layer is arranged on the surface of the thin plate so as to be positioned on the thin-plate surface side, and is subjected to thermal lamination. Further, a hot melt resin may be coated on the surface of the aluminum thin plate to form a hot melt resin layer, and then an organic resin film may be thermally laminated on the hot melt resin layer by a hot roll method or the like.

The hot melt resin desirably has high rigidity in a state where the hot melt resin layer is formed, and for example, a polyester hot melt resin or a nylon hot melt resin can be used. Particularly, from the viewpoint of preventing layer separation destruction at the boundary between the hot melt resin layer and the porous organic resin film at the time of opening by the pull-top mechanism, use the same resin material as the hot melt resin and the porous organic resin film. Is preferred.

The hot-melt resin layer has a thickness of 2 to 5 μm mainly from the viewpoint of tearability (especially prevention of generation of hairing).
m.

As the means for coating the hot melt resin, for example, a hot melt resin is dissolved in a liquid medium such as an organic solvent or water, and this solution is applied to a thin aluminum plate by dipping, spraying or roll coating. Alternatively, a method may be employed in which the hot melt resin is melted, and the melt is coated on a thin aluminum plate by a roll coater method or the like. Usually, a hot melt resin layer is formed by performing a drying treatment after coating with such a hot melt resin.

The step of perforating a large number of non-perforated holes in the organic resin film can be performed, for example, by using a porous film manufacturing apparatus disclosed in Japanese Patent Publication No. 6-61859. When drilling this unpenetrated hole, 0.5 to
It is desirable that fine non-through holes having an average opening diameter of 100 μm, more preferably 2 to 50 μm are opened at a density of 500 or more / cm ² or more. A porous heat-fusible organic resin film or organic resin film having pores with such an average opening diameter and density has a tear strength that is lower than that of a non-porous heat-fusible organic resin film or organic resin film. And exhibit sufficiently high tearability (breakability) as compared with a non-porous heat-fusible organic resin film or an organic resin film.

Here, the non-through hole means a hole having a remaining portion of the film at the bottom of the hole. The remaining portion (remaining thin film) preferably has a thickness of 2 to 5 μm.

The reason why the average opening diameter of the non-through holes is specified at the time of the perforating operation is as follows.
If the average opening diameter is less than 0.5 μm, it may be difficult to easily open the lid formed by laminating the porous heat-fusible organic resin film or the organic resin film by a pull-top mechanism. On the other hand, when the average opening diameter exceeds 100 μm, moisture and the like easily penetrate into the porous heat-fusible organic resin film or the porous organic resin film on the outer surface of the lid, and corrosion occurs at the rib portion with the main body. And it may be difficult to effectively protect the lid. More preferably, the average opening diameter of the non-through holes is 2 to 50 μm.

The reason for defining the density of the non-through holes at the time of the perforating operation is as follows. When the density is less than 500 pieces / cm ² , it becomes difficult to form a porous heat-fusible organic resin film or an organic resin film having high tearability on the outer surface of the lid. The upper limit of the density is not particularly limited. However, through-holes having a density of 25,000 / cm ² can be formed by one treatment using the above-described porous film manufacturing apparatus. More preferably, the density of the through holes is 10
The number is from 00 pieces / cm ^{2 to} 5000 pieces / cm ² .

It is permissible to further laminate an easily breakable organic resin film on the surface of the aluminum thin plate which is on the inner surface side in the lid state by the methods (1) to (5) described in the third embodiment. I do. By laminating such an easily breakable organic resin film on the surface of the aluminum thin plate on the inner surface side in the lid state,
A lid is made from this thin plate, and in a pull-top can manufactured by incorporating the same, the content can be prevented from directly contacting aluminum, which is a material of the lid, and the content can be protected. .

The can body is made of, for example, steel or aluminum.

Next, a method for manufacturing a pull-top can according to the fifth embodiment will be described more specifically with reference to the drawings.

First, as shown in FIG. 42 (a), a heat-fusible organic resin film 92 is directly thermally laminated on one side of the aluminum thin plate 91 (the surface which becomes the outer surface in the state of the lid). Then, a heat-fusible organic resin film 93 having a thickness of 5 to 15 μm is directly thermally laminated on the surface on the opposite side (the surface which becomes the inner surface in the state of the lid) to produce a laminated aluminum thin plate 94. At this time, either of the heat-fusible resin films 92 and 93 may be thermally laminated first or simultaneously.

Next, FIG. 44 and FIG.
No. 61859, the laminated aluminum thin plate 94 is placed between the first roll 111 and the second roll 112 of the apparatus for manufacturing a porous film, and the heat-fusible organic resin film 92 is located on the first roll 111 side. From below. Here, the first roll 111
As shown in FIG. 45, a large number of diamond particles 115 are electrodeposited via an electrodeposition layer 116 on the surface of a metal roll 114 on which a rotating shaft 113 is axially attached. The second roll 112 includes a metal roll 118 on which a rotating shaft 117 is mounted.
Consists of After inserting the laminated aluminum thin plate 94 from below between the first roll 111 and the second roll 112, the first and the second rolls are pressed by a pressing means (not shown).
By rotating the first and second rolls 111 and 112 as shown in FIG. 44 in a state where the second rolls 111 and 112 are pressed so as to approach each other, as shown in FIG. A large number of fine non-through holes 95 are formed in the adhesive organic resin film 92 to form a porous heat-fusible organic resin film (porous heat-fusible organic resin film) 96.

Next, the aluminum thin plate 91 having a porous heat-fusible organic resin film 96 formed on one surface and a porous heat-fusible organic resin film 92 formed on the other surface is punched into a circular shape. The thin plate 91 and both sides of the porous heat-fusible organic resin film 96 and the heat-fusible organic resin are pressed from the side of the porous heat-fusible organic resin film 96 (the side that becomes the outer surface in the state of the lid). After forming an unsealing portion formed of a horseshoe-shaped groove in the film 92, a tab is pin-joined to the coating surface (outer surface) of the porous heat-fusible organic resin film 96, thereby forming the pull-top mechanism 5 shown in FIG.
1 was manufactured. As shown in FIG. 43, the pull-top mechanism 51 is formed by pressing a shoe-shaped dent 53 formed on the outer surface of the lid 52 by pressing and forming a curved surface area of the dent 53 by pressing. Opening portion 54 consisting of a horseshoe-shaped groove where a cut is formed sometimes
And an elongated tab 56 having two holes that are joined to the concave portion 53 on the opposite side of the unsealing portion 54 by a pin 55 located near the center and that comes into contact with the surface of the concave portion 53. I have.

Next, the lid 52 having the pull-top mechanism 51 is swaged to the upper opening of the can body 58 in which the organic resin film 57 is laminated on the inner surface (the outer surface as necessary) as in the third embodiment. By joining, the pull-top can 59 for soft drink shown in FIGS. 46 and 47 is manufactured. Here, FIG. 46 is a cross-sectional view of the shoulder portion of the pull-top can, and FIG. 47 is an enlarged cross-sectional view of the lid of FIG.

The process of laminating an organic resin film on the aluminum thin plate 91 and perforating the non-through holes is not limited to the processes of FIGS. 42A and 42B described above. An organic resin film may be laminated by the methods (1) to (7), and a non-through hole may be formed.

(1) As shown in FIG. 48 (a), a heat-fusible organic resin film 92 is directly thermally laminated on one surface (a surface which becomes an outer surface in the state of a lid) of an aluminum thin plate 91, and A heat-fusible organic resin film 97 is directly thermally laminated on the surface opposite to the surface 91 (the surface that becomes the inner surface in the state of the lid) to form a laminated aluminum thin plate 9.
4 is produced. At this time, the heat-fusible resin film 9
2, 97 may be thermally laminated first or simultaneously.

Next, the laminated aluminum thin plate 94 is inserted from below into the space between the first roll 111 and the second roll 119 of the apparatus for manufacturing a porous film shown in FIG. Here, the first roll 111 has a rotating shaft 113.
A large number of diamond particles 115 are electrodeposited via a electrodeposition layer (not shown) on the surface of a metal roll 114 on which is attached. In the second roll 119, a large number of diamond particles 120 are electrodeposited on a surface of a metal roll 118 on which a rotating shaft 117 is axially attached via an electrodeposition layer (not shown). Thus, the first roll 111 and the second roll 11
9, after inserting the laminated aluminum thin plate 94 from below, the first and second rolls 111 and 119 are pressed by pressing means (not shown) so as to approach each other. 111 and 119 in FIG.
As shown in FIG. 48B, a large number of fine non-through holes 95 and 98 are formed in the heat-fusible organic resin films 92 and 97 to make the heat-fusible organic resin porous. Resin film (porous heat-sealable organic resin film) 9
6,99 are formed.

(2) As shown in FIG. 50 (a), one side of the aluminum thin plate 91 (the surface which becomes the inner surface in the state of the lid) is roll-coated with a melt of a hot melt resin and dried to obtain a hot melt. The resin layer 100 is formed. Subsequently, as shown in FIG. 50 (b), a heat-fusible organic resin film 92 was directly hot-laminated on the opposite surface of the aluminum thin plate 91 (the surface which becomes the outer surface in the cover state) by hot pressing. Thereafter, a thin organic resin film 101 having a thickness of 5 to 12 μm is hot-pressed and thermally laminated on the hot melt resin layer 100 to produce a laminated aluminum thin plate 94. At this time, the organic resin film 1
01 may be thermally laminated first, or the heat-fusible organic resin film 92 and the organic resin film 101 may be simultaneously thermally laminated.

Next, the first roll 111 and the second roll 112 of the porous film manufacturing apparatus disclosed in Japanese Patent Publication No. 6-61859 shown in FIGS.
The laminated aluminum thin plate 94 is inserted from below so that the heat-fusible organic resin film 92 is positioned on the first roll 111 side, and the first and second rolls 111 and 112 are pressed by a pressing means (not shown). The first and second rolls 111 and 1 are pressed in a state where
44 is rotated as shown in FIG. 44 to form a plurality of fine non-through holes 95 in the heat-fusible organic resin film 92 as shown in FIG. Resin film (porous heat-sealable organic resin film)
Form 96.

(3) As shown in FIG. 51 (a), one surface of the aluminum thin plate 91 (the surface which becomes the inner surface in the state of the lid) is roll-coated with a hot melt resin melt and dried to obtain a hot melt. The resin layer 100 is formed. Subsequently, as shown in FIG. 51 (b), the heat-fusible organic resin film 92 was directly hot-laminated on the opposite surface (the surface that becomes the outer surface in the lid state) of the aluminum thin plate 91 by hot pressing. Thereafter, the organic resin film 102 is hot-pressed on the hot melt resin layer 100 and thermally laminated to produce a laminated aluminum thin plate 94. At this time, the organic resin film 102 may be thermally laminated first, or the heat-fusible organic resin film 92 and the organic resin film 102 may be simultaneously thermally laminated.

Next, the first roll 111 and the second roll 1 of the porous film manufacturing apparatus shown in FIG.
19, the laminated aluminum thin plate 94 is inserted from below, and the first and second rolls 111 and 119 are pressed by pressing means (not shown) so as to approach each other. , 119 are rotated as shown in FIG. 49 to form fine non-through holes 95 in the heat-fusible organic resin film 92 as shown in FIG.
And a porous heat-fusible organic resin film (porous heat-fusible organic resin film) 96 formed by perforating a large number of fine through-holes 103 in the organic resin film 102 and a porous organic resin film. A resin film (porous organic resin film) 104 is formed.

(4) As shown in FIG. 52 (a), one side of the aluminum thin plate 91 (the surface that becomes the outer surface in the state of the lid) is roll-coated with a hot melt resin melt and dried to obtain a hot melt. The resin layer 100 is formed. Subsequently, as shown in FIG. 52 (b), a heat-fusible organic resin film 93 having a thickness of 5 to 15 μm is hot-pressed on the surface on the opposite side of the aluminum thin plate 91 (the surface which becomes the inner surface in a lid state). After direct thermal lamination, the organic resin film 105 is hot-pressed on the hot melt resin layer 100 and thermally laminated to produce a laminated aluminum thin plate 94. At this time, the organic resin film 102
Or the organic resin film 102 may be thermally laminated at the same time.

Next, the first roll 111 and the second roll 112 of the apparatus for manufacturing a porous film disclosed in Japanese Patent Publication No. 6-61859 shown in FIGS.
In between, the laminated aluminum thin plate 94 is inserted from below so that the organic resin film 105 is positioned on the first roll 111 side, and the first and the first are pressed by pressing means (not shown).
By rotating the first and second rolls 111 and 112 as shown in FIG. 44 in a state where the second rolls 111 and 112 are pressed so as to approach each other, an organic resin is formed as shown in FIG. Fine non-through hole 1 in film 105
06 are perforated to form a porous organic resin film (porous thermal organic resin film) 107.

(5) As shown in FIG. 53 (a), one side of the thin aluminum plate 91 (the surface which becomes the outer surface in the state of the lid) is roll-coated with a melt of a hot melt resin and dried to obtain a hot melt. The resin layer 100 is formed. Subsequently, as shown in FIG. 53 (b), a heat-fusible organic resin film 97 was directly hot-laminated on the opposite surface of the aluminum thin plate 91 (the inner surface in the cover state) by hot pressing. After that, the organic resin film 105 is hot-pressed on the hot melt resin layer 100 and thermally laminated to produce a laminated aluminum thin plate 94. At this time, the organic resin film 105 may be thermally laminated first, or the heat-fusible organic resin film 97 and the organic resin film 105 may be simultaneously thermally laminated.

Next, the first roll 111 and the second roll 1 of the porous film manufacturing apparatus shown in FIG.
19, the laminated aluminum thin plate 94 is inserted from below, and the first and second rolls 111 and 119 are pressed by pressing means (not shown) so as to approach each other. , 119 are rotated as shown in FIG. 49 to form a large number of fine non-through holes 106 in the organic resin film 105 as shown in FIG. An organic resin film (porous organic resin film) 107 and a porous heat-fusible organic resin film (porous heat-fusible organic resin film) 99 which are made porous by forming a large number of non-through holes 98 are respectively formed. Form.

(6) As shown in FIG. 54 (a), a hot melt resin melt is roll-coated on both sides of an aluminum thin plate 91 and dried to form a hot melt resin layer 100. Then, FIG. 54 (b)
As shown in FIG. 3, an organic resin film 105 is hot-pressed and thermally laminated on one side (the side which becomes the outer surface in the lid state) of the aluminum thin plate 91, and then the hot-melt resin layer 100 on the opposite side is formed. The organic resin film 101 having a thickness of 5 to 12 μm is hot-pressed and thermally laminated to form a laminated aluminum sheet 9
4 is produced. At this time, the thin organic resin film 10
Alternatively, the organic resin films 105 and 101 may be thermally laminated at the same time.

Next, the first roll 111 and the second roll 112 of the porous film manufacturing apparatus disclosed in Japanese Patent Publication No. 6-61859 shown in FIGS.
In between, the laminated aluminum thin plate 94 is inserted from below so that the organic resin film 105 is positioned on the first roll 111 side, and the first and the first are pressed by pressing means (not shown).
By rotating the first and second rolls 111 and 112 as shown in FIG. 44 in a state where the second rolls 111 and 112 are pressed so as to approach each other, an organic resin is formed as shown in FIG. Fine non-through hole 1 in film 105
06 are perforated to form a porous organic resin film (porous thermal organic resin film) 107.

(7) As shown in FIG. 55 (a), a hot melt resin melt is roll-coated on both sides of an aluminum thin plate 91 and dried to form a hot melt resin layer 100. Then, FIG. 54 (b)
As shown in FIG. 3, an organic resin film 105 is hot-pressed and thermally laminated on one side (the side which becomes the outer surface in the lid state) of the aluminum thin plate 91, and then the hot-melt resin layer 100 on the opposite side is formed. The organic resin film 102 is hot-pressed and thermally laminated to produce a laminated aluminum thin plate 94. At this time, the organic resin film 102 may be thermally laminated first, or the organic resin films 105 and 102 may be simultaneously thermally laminated.

Next, the first roll 111 and the second roll 1 of the porous film manufacturing apparatus shown in FIG.
19, the laminated aluminum thin plate 94 is inserted from below, and the first and second rolls 111 and 119 are pressed by pressing means (not shown) so as to approach each other. , 119 are rotated as shown in FIG. 49 to form a large number of fine non-through holes 106 in the organic resin film 105 as shown in FIG. A large number of perforated organic resin films (porous organic resin films) 107 and porous organic resin films (porous organic resin films) 104 are formed.

In the method of manufacturing a pull-top can according to the fifth embodiment described above, a can body having an open top and an inner surface laminated with an organic resin film is attached to the opening of the can body by, for example, caulking. In producing a pull-top can having an aluminum lid having a pull-top mechanism, a heat-fusible organic resin film is directly thermally laminated on one side of an aluminum thin plate, or the organic resin film is interposed through an adhesive layer. After thermal lamination, after piercing a large number of fine non-through holes in the heat-fusible organic resin film or the organic resin film,
The method includes a step of forming an external shape and a lid in which the porous heat-fusible organic resin film or the organic resin film is located on the outer surface side by performing the outer shape processing and the formation of the pull-top mechanism.

In the pull-top type can manufactured by such a method, as shown in FIGS. 29 and 30, the can main body is held by one hand (not shown), and the other hand (not shown). The tab 56 of the pull-top mechanism 51 is
29, the end of the dove 56 near the joint of the pin 55 is positioned on the inside of the horseshoe-shaped opening portion 54 as shown in FIG. Pressed toward 58 side. At the time of pressing the end of the tab 56, as shown in FIGS. A porous heat-fusible organic resin film 96 that is easily torn is formed. For this reason, notches are formed along the grooves of the horseshoe-shaped opening portion 54 not only in the lid 52 but also in the porous heat-sealable organic resin film 96, as shown in FIGS.
0, the lid 52 inside the horseshoe-shaped opening portion 54
The portion is bent toward the inside of the can body 58 and opened. At this time, the lid 52 can be opened without any hair ring called an angel mark on the outside of the lid 52.

More specifically, when the end of the tab 56 presses the lid 52 inside the horseshoe-shaped opening portion 54, the heat-fusing organic resin film 92 directly thermally laminated on the outer surface of the lid 52 is pressed. In the porous heat-fusible organic resin film 96 formed by perforating a large number of the non-through holes 95, the non-through holes 95 function as tearing starting points (rupture starting points). Therefore, in the initial stage of the pressing, a cut is formed along the groove of the unsealing portion 54 located around the pressing portion as shown in FIGS. 56 and 57, and at the same time, the porous heat-fusible organic resin film 96 is cut. Also, a cut is formed along the groove of the opening portion 54. Further, when the tab 56 is vertically erected, the pressing stroke on the lid 52 located inside the horseshoe-shaped opening portion 54 becomes longer.
For this reason, the groove of the opening portion 54 is cut long together with the porous heat-fusible organic resin film 96, and the lid 52 inside the horseshoe-shaped opening portion 54 faces the inside of the can main body 58. The lid 52 can be opened without any hair ring called an angel mark on the outside of the lid 52.

By the way, the present inventor has studied the mechanism of the occurrence of hairing in the pull-top can described in JP-A-11-171179 described in the prior art. As a result, when a porous organic resin film is laminated on the outer surface of the lid of the pull-top can, a heat-fusible adhesive (for example, a two-component polyester polyurethane-based adhesive) is co-extruded onto the porous organic resin film. The laminated film is placed on the outer surface of the lid so that the adhesive layer is positioned on the lid side and is subjected to thermal lamination. Therefore, the thickness of the adhesive layer is not controlled, and the laminated film is partially improper. It has been clarified that the uniformity is obtained and that the stretchability of the adhesive layer is higher than that of the porous organic resin film. That is, when the lid portion located inside the horseshoe-shaped opening portion is bent toward the inside of the can main body at the time of pressing the tab end described above, the porous organic resin film is easily broken. This causes a layer separation failure at the boundary of the adhesive layer (particularly at the position of the adhesive layer having a small thickness) so that the adhesive layer extends without following the breakage of the porous organic resin film. It has been found that hairing called the angel mark occurs at the position (1).

For this reason, in manufacturing the lid, as shown in FIGS. 42A and 42B, one surface of the aluminum thin plate 91 as the lid material (the surface which becomes the outer surface in the lid state). ) Is directly thermally laminated with a heat-fusible organic resin film 92,
A large number of minute non-through holes 95 are formed so that the lid 52 located inside the horseshoe-shaped opening portion 54 when the end of the tab 56 is pressed is directed toward the inside of the can body 58. At the time of bending, the heat-fusible organic resin film 92 does not cause layer separation destruction near the interface of the outer surface of the lid 52, and is easily broken with the large number of non-through holes 95 as breaking points to form an adhesive layer. It can be opened without any hair ring called an angel mark on the outer surface of the lid 52 as when used.

[0230] In particular, when the method of directly laminating a porous heat-fusible organic resin film in which holes such as through-holes have already been perforated in the above-described second embodiment to an aluminum thin plate is adopted, the perforated layer may be used. The quality heat-fusible organic resin film may be affected by heat and the rupture property due to the pores may be reduced. On the other hand, the fifth
In the embodiment, a heat-fusible organic resin film 92 is directly thermally laminated on one surface (a surface which becomes an outer surface in a lid state) of an aluminum thin plate 91, and fine non-through holes 95 are formed in the heat-fusible organic resin film 92. By forming a large number of holes, there is no thermal effect in the non-through holes 95, so that the breakability caused by the non-through holes 95 can be effectively exhibited. As a result, it is possible to open the lid 52 more effectively while preventing the generation of hair ring called an angel mark on the outer surface of the lid 52. In the production of the lid, FIGS.
From (c) to (a) to (c) of FIG. 55, one surface (a surface which becomes an outer surface in a lid state) of an aluminum thin plate 91 as a lid material is coated with a hot melt resin to have a uniform thickness. The hot-melt resin layer 100 is formed, an organic resin film 105 is thermally laminated on the hot-melt resin layer 100, and a large number of fine non-through holes 106 are formed in the organic resin film 105. When the lid 52 located inside the horseshoe-shaped opening portion 54 is bent toward the inside of the can body 58 due to the pressing of the portion, the thickness of the hot melt resin layer 100 is caused to be non-uniform. When the hot melt resin layer 100 is easily broken at the boundary between the lid 52 and the plurality of non-through holes 105 as break points without using the adhesive layer, Can open without referred hair ring and Angel mark the outer surface of the cover 52 such that at all occur.

Also, as shown in FIGS. 42A and 42B, a thin heat-fusible organic resin film 93 is directly applied to the surface opposite to the aluminum thin plate 91 (the surface which becomes the inner surface in the state of the lid). By thermal lamination, when the pull-top mechanism 56 of the lid 52 made of this thin plate is opened, hair ring called feathering occurs on the inner surface side of the lid 52 without impairing the opening property. Can be prevented. 48, 50 to 5 described above.
As shown in FIG. 5, an easily breakable organic resin film is laminated on the surface on the opposite side of the aluminum thin plate 61 (the surface that becomes the inner surface in the state of the lid), and the lid 52 made of this thin plate also has At the time of opening the mechanism 56, it is possible to prevent the occurrence of hair ring called feathering on the inner surface side of the lid 52 without impairing the opening property.

Therefore, the pull-top can manufactured by the method of the fifth embodiment can be either directly thermally laminated with a heat-fusible organic resin film on one side of an aluminum thin plate or bonded with an organic resin film when manufacturing the lid. Thermal lamination through an agent layer, and by perforating a large number of fine non-through holes in the heat-fusible organic resin film or the organic resin film, without impairing the openability of the pull-top mechanism, and appearance. It can be easily opened without causing a hair ring called an angel mark that impairs the image quality. In addition, since a porous heat-fusible organic resin or organic resin film is thermally laminated on the outer surface of the lid, the outer surface of the lid can be protected from the outside.

Further, by laminating an organic resin film on the inner surface of the can body by thermal lamination and laminating an easily breakable organic resin film on the surface of the aluminum thin plate which is the inner surface in the state of the lid when preparing the lid. The content in the can is prevented from being oxidized due to the direct contact with the material such as aluminum of the can body and the lid, and the quality can be maintained for a long time.

Further, when producing the lid, a heat-fusible organic resin film was directly thermally laminated on one side of the thin aluminum plate (the surface which becomes the outer surface in the state of the lid), or the organic resin film was laminated with an adhesive layer. Thermal lamination and laminating an easily breakable organic resin film on the opposite side of the aluminum thin plate (the surface that becomes the inner surface in the state of the lid). In addition, a washing step that requires an enormous amount of water after painting as in conventional baking painting can be omitted, and the running cost can be greatly reduced.

[0235]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings.

Example 1 A 9 μm-thick amorphous polyester film (Ostar Copolyester film manufactured by Okura Kogyo Co., Ltd.) was directly applied to both sides of a 280 μm-thick aluminum thin plate using a hot roll at a temperature of 170 ° C. Thermal lamination was performed. Subsequently, the aluminum sheet was punched out in a circular shape and pressed from the amorphous polyester film side (the side that becomes the outer surface in the state of the lid) to form a horseshoe-shaped sheet on the sheet and the amorphous polyester film on both sides. After forming an opening portion formed of a groove and the like, a tab was joined to the covering surface (outer surface) of the amorphous polyester film with a pin to produce, for example, the above-described lid body 52 having the pull-top mechanism 51 shown in FIG. The lid having the pull-top mechanism was caulked and joined to the upper opening of a steel can body having a polyethylene terephthalate film laminated on the inner surface and the outer surface, thereby producing a pull-top can shown in FIGS. 22 and 23, for example.

(Example 2) A 15 μm-thick amorphous polyester film (Ostar Copolyester film manufactured by Okura Kogyo Co., Ltd.) on both sides of a 280-thick aluminum thin plate
Were directly subjected to thermal lamination using a hot roll at a temperature of 170 ° C. Subsequently, this laminated aluminum thin plate is processed in the same manner as in the first embodiment to produce, for example, the lid 52 having the above-described pull-top mechanism 51 shown in FIG. For example, a pull-top can shown in FIGS. 22 and 23 was manufactured by caulking and joining to the opening.

Comparative Example 1 An amorphous polyester film having a thickness of 20 μm (Ooster Co. polyester film manufactured by Okura Kogyo Co., Ltd.) was directly applied to both sides of an aluminum sheet having a thickness of 280 μm using a hot roll at a temperature of 170 ° C. Thermal lamination was performed. Subsequently, the laminated aluminum thin plate is processed in the same manner as in the first embodiment, and the lid 52 having the pull-top mechanism 51 shown in FIG.
Then, the lid is caulked and joined to the upper opening of the can body in the same manner as in Example 1 to obtain, for example, FIGS.
Was manufactured.

Comparative Example 2 An amorphous polyester film having a thickness of 20 μm (Ooster Co. polyester film manufactured by Okura Kogyo Co., Ltd.) was directly applied to both sides of an aluminum sheet having a thickness of 280 μm using a hot roll at a temperature of 170 ° C. Thermal lamination was performed. Subsequently, the laminated aluminum thin plate is processed in the same manner as in the first embodiment, and the lid 52 having the pull-top mechanism 51 shown in FIG.
Then, the lid is caulked and joined to the upper opening of the can body in the same manner as in Example 1 to obtain, for example, FIGS.
Was manufactured.

(Example 3) A porous amorphous polyester film having a thickness of 15 µm was directly thermally laminated on both surfaces of an aluminum thin plate having a thickness of 280 µm using a hot roll at a temperature of 170 ° C. The porous amorphous polyester film located on the outer surface side in a lid state has an Oster Copolyester film manufactured by Okura Kogyo Co.
5000 through holes / c having an average opening diameter of 80 μm
It has a structure in which a large number of holes are uniformly opened at a density of m ² .
The porous amorphous polyester film positioned on the inner surface side in a lid state is obtained by forming an Oster Copolyester film manufactured by Okura Kogyo Co., Ltd. at a density of 5,000 non-through holes having an average opening diameter of 70 to 80 μm at 5000 / cm ² . It has a structure with many and uniformly opened holes. Subsequently, this laminated aluminum thin plate is processed in the same manner as in the first embodiment to produce, for example, the lid 52 having the above-described pull-top mechanism 51 shown in FIG. For example, a pull-top can shown in FIGS. 22 and 23 was manufactured by caulking and joining to the opening.

(Example 4) A porous amorphous polyester film having a thickness of 25 µm was directly thermally laminated on both surfaces of an aluminum thin plate having a thickness of 280 µm using a hot roll at a temperature of 170 ° C. The porous amorphous polyester film located on the outer surface side in a lid state has an Oster Copolyester film manufactured by Okura Kogyo Co.
5000 through holes / c having an average opening diameter of 80 μm
It has a structure in which a large number of holes are uniformly opened at a density of m ² .
The porous amorphous polyester film positioned on the inner surface side in a lid state is obtained by forming an Oster Copolyester film manufactured by Okura Kogyo Co., Ltd. at a density of 5,000 non-through holes having an average opening diameter of 70 to 80 μm at 5000 / cm ² . It has a structure with many and uniformly opened holes. Subsequently, this laminated aluminum thin plate is processed in the same manner as in the first embodiment to produce, for example, the lid 52 having the above-described pull-top mechanism 51 shown in FIG. For example, a pull-top can shown in FIGS. 22 and 23 was manufactured by caulking and joining to the opening.

(Example 5) A melt of polyester hot melt resin (trade name, manufactured by Toyobo Co., Ltd .; Byron GM-400) was roll-coated on both sides of a thin aluminum plate having a thickness of 280 μm, and dried to a thickness of 3 μm. Was formed. Subsequently, a 9 μm-thick general-purpose polyester film was thermally laminated on each of these hot melt resins using a hot roll at a temperature of 150 ° C., respectively. Subsequently, the laminated aluminum thin plate is processed in the same manner as in the first embodiment to produce, for example, the above-described lid 52 having the pull-top mechanism 51 shown in FIG. For example, a pull-top can shown in FIGS.

Example 6 A 280 μm-thick aluminum thin plate was roll-coated on both sides with a melt of a polyester hot melt resin (trade name: Byron GM-400, manufactured by Toyobo Co., Ltd.) and dried to a thickness of 3 μm. Was formed. Subsequently, two porous polyester films were prepared, in which a large number of uniform through holes having an average opening diameter of 70 to 80 μm were formed at a density of 5000 / cm ² on a general-purpose polyester film having a thickness of 12 μm. These porous polyester films were applied to the hot melt resin layers on both sides of the aluminum thin plate, respectively.
Thermal lamination was performed by hot pressing at 50 ° C. Subsequently, this laminated aluminum sheet was used in Example 1
For example, a lid 52 having the above-described pull-top mechanism 51 shown in FIG. 21 is manufactured in the same manner as in FIG. The pull-top can shown in FIG. 23 was manufactured.

(Comparative Example 3) Polyester hot melt resin having a thickness of 3 μm (trade name, manufactured by Toyobo Co., Ltd .; Byron GM)
-400) are prepared by laminating two general-purpose polyester films having a thickness of 9 μm, and laminating these laminated polyester films on both surfaces of an aluminum thin plate having a thickness of 280 μm such that the hot melt resin is located on the aluminum thin plate side. The layers were stacked and thermally laminated using a hot roll at a temperature of 150 ° C. Subsequently, this laminated aluminum thin plate is processed in the same manner as in the first embodiment to produce, for example, the lid 52 having the above-described pull-top mechanism 51 shown in FIG. For example, a pull-top can shown in FIGS. 22 and 23 was manufactured by caulking and joining to the opening.

(Comparative Example 4) A melt of a polyester hot melt resin (trade name, manufactured by Toyobo Co., Ltd .; Byron GM-400) was roll-coated on both sides of a 280 μm-thick aluminum thin plate and dried to a thickness of 3 μm. Was formed. Subsequently, a general-purpose polyester film having a thickness of 25 μm was thermally laminated on each of the hot melt resins using a hot roll at a temperature of 150 ° C. Subsequently, this laminated aluminum thin plate was processed in the same manner as in Example 1 and, for example, FIG.
A lid 52 having a pull-top mechanism 51 shown in FIG.
This lid was caulked and joined to the upper opening of the can body in the same manner as in Example 1 to produce, for example, a pull-top can shown in FIGS.

(Example 7) An amorphous polyester film having a thickness of 15 µm (Ooster Copolyester film manufactured by Okura Kogyo Co., Ltd.) was formed on one surface (a surface which becomes an outer surface in the state of a lid) of an aluminum thin plate having a thickness of 280 µm. A 9 μm-thick amorphous polyester film (Ooster Co. polyester film manufactured by Okura Kogyo Co., Ltd.) is directly applied to the other surface (the surface that becomes the inner surface in the state of the lid) using a hot roll at a temperature of 170 ° C. Thermal lamination was performed.

Next, the laminated aluminum thin plate is connected to the above-mentioned Japanese Patent Publication No. 6-61859 shown in FIGS.
No. 6,098,098, the first and second rolls 11 are inserted from below into a first roll 111 and a second roll 112 of the porous film manufacturing apparatus disclosed in
When the first and second rolls 111 and 112 are rotated as shown in FIG. 44 while the first and second rolls 112 and 112 are pressed close to each other, the state of the lid as shown in FIG. Thickness 1 laminated on the outer surface
12 μm depth on 5 μm amorphous polyester film 92
m, non-through hole 95 having an average opening diameter of 70 to 80 μm
Were perforated at a density of 5000 / cm ² to form a porous amorphous polyester film 96.
Subsequently, an aluminum thin plate in which the porous amorphous polyester film is laminated on one side and the thin amorphous polyester film is laminated on the other side is processed in the same manner as in Example 1 and, for example, the pull top shown in FIG. Mechanism 5
1, a lid 52 having the porous amorphous polyester film laminated on the outer surface is manufactured, and the lid is caulked and joined to the upper opening of the can body in the same manner as in Example 1, for example. The pull-top can shown in FIGS. 22 and 23 was manufactured.

(Example 8) A melt of a polyester-based hot melt resin (trade name: Byron GM-400, manufactured by Toyobo Co., Ltd.) on one surface of a thin aluminum plate having a thickness of 280 μm (the surface that becomes the outer surface in the state of a lid). Was roll-coated and dried to form a hot-melt resin layer having a thickness of 3 μm. Subsequently, a 15 μm-thick general-purpose polyester film was thermally laminated on the hot melt resin by using a hot roll at a temperature of 150 ° C., and then the other surface of the aluminum thin plate (the surface which became an inner surface in a lid state) was thickened. 9μ
m of an amorphous polyester film (Ooster Co. polyester film manufactured by Okura Industry Co., Ltd.) was directly thermally laminated using a hot roll at a temperature of 170 ° C.

Next, the laminated aluminum thin plate is connected to the above-mentioned Japanese Patent Publication No. 6-61859 shown in FIGS.
No. 6,098,098, the first and second rolls 11 are inserted from below into a first roll 111 and a second roll 112 of the porous film manufacturing apparatus disclosed in
When the first and second rolls 111 and 112 are rotated as shown in FIG. 44 while the first and second rolls 112 and 112 are pressed close to each other, the state of the lid as shown in FIG. Thickness 1 laminated on the outer surface
12 μm depth on 5 μm polyester film 105,
A number of non-through holes 106 having an average opening diameter of 70 to 80 μm were perforated in a large number at a density of 5000 / cm ² to form a porous polyester film 107. Subsequently, an aluminum thin plate in which the porous polyester film is laminated on one surface and a thin amorphous polyester film is laminated on the other surface is processed in the same manner as in Example 1, and for example, the pull-top mechanism 51 shown in FIG. A lid 52 having the above-mentioned porous amorphous polyester film laminated on the outer surface is manufactured, and the lid is caulked to the upper opening of the can main body in the same manner as in Example 1 to obtain, for example, FIG. The pull-top can shown in FIG. 23 was manufactured.

The above-described Examples 1 to 8 and Comparative Examples 1 to 4
Each of the 10 pull-top type cans is prepared, and after opening at the position of the pull-top mechanism of these cans, an angel mark (outside of the lid) and a feather ring (inside of the lid) around the opening portion of the lid. The number of occurrences of was observed. The results are shown in Tables 1 and 2 below.

[0251]

[Table 1]

[0252]

[Table 2]

As is clear from Tables 1 and 2, after the pull-top cans of Examples 1 to 8 were opened at the position of the pull-top mechanism, there was no occurrence of angel marks and feathering around the opening of the lid. It shows that the appearance after opening was good.

In the first to eighth embodiments, the pull-top can for soft drinks has been described. However, the same applies to a pull-top can for accommodating seafood and the like whose entire lid is opened from the periphery of the opening of the can body. Can be applied to

It should be noted that the present invention encompasses the claims of the basic application described below, as is clear from the above description.

(1) A can body having an opening at the top and an inner surface laminated with an organic resin film, and an aluminum lid having a pull-top mechanism, which is caulked and joined to the opening of the can body, The lid body is directly thermally laminated with a porous heat-fusible organic resin film having a large number of at least one hole selected from fine through holes and non-through holes on the outer surface, and has fine through holes and non-through holes on the inner surface. A pull-top can, wherein a porous organic resin film having a large number of at least one hole selected from holes is laminated.

In the pull-top can of the above (1), the heat-fusible organic resin film is preferably an amorphous unstretched polyethylene terephthalate film.

In the pull-top can of the above item (1), the porous heat-fusible organic resin film has a thickness of 5 to 30 μm, a fine through-hole having an average opening diameter of 5 to 100 μm, and a fine through-hole. It is preferable that at least one hole selected from the through holes is formed at a density of 500 / cm ² or more.

In the pull-top can of the above (1), it is preferable that the porous organic resin film is laminated on the inner surface of the lid via an adhesive layer.

In the pull-top can of the above (1), the porous organic resin film has a thickness of 5 to 40 μm,
In addition, it is preferable that at least one hole selected from fine through holes and non-through holes having an average opening diameter of 0.5 to 100 μm is formed at a density of 500 / cm ² or more.

(2) A pull-top can having a can body having an open top and an inner surface laminated with an organic resin film, and an aluminum lid having a pull-top mechanism, which is crimped to the opening of the can body. In the production of, after hot-melt resin is coated on both sides of an aluminum thin plate to form a hot-melt resin layer, a porous organic resin film having a large number of fine through holes is thermally laminated on each of these hot-melt resin layers. A process for producing a lid by performing outer shape processing and forming the pull-top mechanism.

In the method (2) for producing a pull-top can, the hot melt resin is preferably of a polyethylene terephthalate type.

In the method (2) for producing a pull-top can, the organic resin film to be made porous is preferably a polyethylene terephthalate film.

In the method for manufacturing a pull-top can of the above (2), the porous organic resin film has a thickness of 5 to 40 μm and a fine through hole having an average opening diameter of 0.5 to 100 μm. It is preferable that holes are formed at a density of not less than pcs / cm ² .

[0265]

As described above in detail, according to the present invention, the openability of the pull-top mechanism attached to the lid is not impaired, and hairing does not occur at all around the opening of the lid. The contents contained in the can body can be protected not only from the body of the can but also from the material of the lid, and the outer surface of the lid can be protected, and thus the quality of the contained soft drinks, beer, other seafood and other contents Can be maintained for a long period of time, and the production cost of the pull-top can can be reduced.

[Brief description of the drawings]

FIG. 1 is a top view of a soft drink pull-top can according to a first embodiment of the present invention.

FIG. 2 is a front view of the pull-top can of FIG.

FIG. 3 is a plan view showing an inner surface of a lid used in the pull-top can of FIG. 1;

FIG. 4 is a sectional view of a shoulder of the pull-top can of FIG. 2;

FIG. 5 is an enlarged sectional view of the lid of FIG. 4;

FIG. 6 is an enlarged sectional view showing another embodiment of the lid.

FIG. 7 is an enlarged sectional view showing still another embodiment of the lid.

FIG. 8 is an enlarged sectional view showing still another embodiment of the lid.

FIG. 9 is a perspective view showing a state in which the pull-top can of FIG. 1 is opened.

FIG. 10 is a perspective view showing the inner surface of the lid of the opened pull-top can of FIG. 9;

FIG. 11 is a perspective view showing the inner surface of the lid of the pull-top can at the initial stage of opening in the pull-top can of FIG. 1;

FIG. 12 is a perspective view of a cross section taken along line XX of FIG. 11;

FIG. 13 is a sectional view of a shoulder of a pull-top can according to a second embodiment of the present invention.

FIG. 14 is an enlarged sectional view of the lid of FIG.

FIG. 15 is an enlarged sectional view showing another form of the lid according to the second embodiment of the present invention.

FIG. 16 is an enlarged sectional view showing still another embodiment of the lid according to the second embodiment of the present invention.

FIG. 17 is an enlarged cross-sectional view showing still another embodiment of the lid according to the second embodiment of the present invention.

FIG. 18 is a perspective view showing the inner surface of the lid of the pull-top can at the initial stage of opening in the second embodiment of the present invention.

19 is a perspective view of a cross section taken along line XX of FIG.

FIG. 20 is a cross-sectional view showing a step of thermally laminating an organic thin film on a thin aluminum plate via a hot-melt resin layer formed in advance in a third embodiment of the present invention.

21 is a plan view showing a lid having a pull-top mechanism manufactured by processing the laminated aluminum thin plate obtained in FIG. 20.

FIG. 22 is a top view showing a soft drink pull-top can manufactured using the lid having the pull-top mechanism of FIG. 21;

FIG. 23 is a front view of the pull-top can of FIG. 22.

FIG. 24 is a sectional view of a shoulder of the pull-top can of FIG. 22;

FIG. 25 is an enlarged sectional view of the lid shown in FIG. 24;

FIG. 26 is a cross-sectional view showing a step of thermally laminating another organic resin film according to the third embodiment of the present invention.

FIG. 27 is a cross-sectional view illustrating a step of thermally laminating another organic resin film according to the third embodiment of the present invention.

FIG. 28 is a cross-sectional view illustrating a step of thermally laminating another organic resin film according to the third embodiment of the present invention.

FIG. 29 is a perspective view showing a state in which the pull-top can of FIG. 23 is opened.

FIG. 30 is a perspective view showing the inner surface of the lid of the opened pull-top can of FIG. 29;

FIG. 31 is a perspective view showing the inner surface side of the lid at the initial stage of opening the pull-top can of FIG. 23;

FIG. 32 is a sectional perspective view taken along line XX of FIG. 31.

FIG. 33 is a cross-sectional view illustrating a step of thermally laminating an organic resin film on a thin aluminum plate via a hot-melt resin layer previously formed according to a fourth embodiment of the present invention.

FIG. 34 is a plan view showing a lid having a pull-top mechanism manufactured by processing the laminated aluminum sheet obtained in FIG. 33.

FIG. 35 is a cross-sectional view of a shoulder in a pull-top can manufactured according to the fourth embodiment of the present invention.

FIG. 36 is an enlarged sectional view of the lid shown in FIG. 35;

FIG. 37 is a sectional view showing a step of thermally laminating another organic resin film according to the fourth embodiment of the present invention.

FIG. 38 is a cross-sectional view showing a step of thermally laminating another organic resin film according to the fourth embodiment of the present invention.

FIG. 39 is a cross-sectional view showing a step of thermally laminating another organic resin film according to the fourth embodiment of the present invention.

FIG. 40 is a perspective view showing the inner surface side of the lid at the initial stage of opening the pull-top can manufactured in the fourth embodiment of the present invention.

FIG. 41 is a sectional perspective view taken along line XX of FIG. 40;

FIG. 42 is a sectional view showing a step of forming an organic resin film on a thin aluminum plate and perforating the same in a fifth embodiment of the present invention.

43 is a plan view showing a lid having a pull-top mechanism manufactured by processing the laminated aluminum sheet obtained in FIG. 42.

FIG. 44 is a perspective view showing a roll structure of an apparatus for making an organic resin film porous.

FIG. 45 is a partially enlarged cross-sectional view of the first roll of FIG. 44.

FIG. 46 is a sectional view of a shoulder of a pull-top can manufactured according to the fifth embodiment of the present invention.

FIG. 47 is an enlarged sectional view of the lid shown in FIG. 46;

FIG. 48 is a cross-sectional view showing another process for forming an organic resin film on an aluminum thin plate and making the same thin and porous in the fifth embodiment of the present invention.

FIG. 49 is a perspective view showing a roll structure of another device for making the organic resin film porous.

FIG. 50 is a cross-sectional view showing another process for forming an organic resin film on a thin aluminum plate and making it porous, according to the fifth embodiment of the present invention.

FIG. 51 is a cross-sectional view showing another process for forming an organic resin film on an aluminum thin plate and making it porous according to the fifth embodiment of the present invention.

FIG. 52 is a cross-sectional view showing another process for forming an organic resin film on an aluminum thin plate and making it porous, according to the fifth embodiment of the present invention.

FIG. 53 is a cross-sectional view showing another process for forming an organic resin film on a thin aluminum plate and making the same thin and porous according to the fifth embodiment of the present invention.

FIG. 54 is a cross-sectional view showing another step for forming an organic resin film on an aluminum thin plate and making it porous, according to the fifth embodiment of the present invention.

FIG. 55 is a cross-sectional view showing another process for forming an organic resin film on an aluminum thin plate and making it porous according to the fifth embodiment of the present invention.

FIG. 56 is a perspective view showing the inner surface side of the lid at the initial stage of opening the pull-top can manufactured in the fifth embodiment of the present invention.

FIG. 57 is a sectional perspective view taken along the line XX of FIG. 56.

[Explanation of symbols]

 1,58: can body, 2, 43a, 57, organic resin film, 3,52 lid, 4 heat-fusible polyester film, 6,51 pull-top mechanism, 8,54 opening part, 10 , 56: tab, 21, 92: porous heat-fusible organic resin film, 24: through hole, 43: porous heat-fusible polyester film, 24, 64: through hole, 65, 107: porous organic resin Film, 95 ... non-through hole,

Claims (20)

[Claims] 1. A can body having an upper part opened and an inner surface laminated with an organic resin film, and an aluminum lid attached to the opening of the can body and having a pull-top mechanism, wherein the lid is provided. Is a pull-top type can, characterized in that a heat-fusible organic resin film having a thickness of 5 to 15 μm is directly thermally laminated on the outer surface. 2. A can body having an open top and an inner surface laminated with an organic resin film, and an aluminum lid attached to the opening of the can body and having a pull-top mechanism, wherein the lid is Is a pull-top can in which a porous heat-fusible organic resin film having a large number of at least one hole selected from fine through holes and non-through holes on its outer surface is directly thermally laminated. 3. The porous heat-fusible organic resin film has at least one hole selected from fine through holes and non-through holes having an average opening diameter of 5 to 100 μm.
3. The pull-top can according to claim 2, wherein holes are opened at a density of 0 / cm ² or more. 4. The pull-top can according to claim 1, wherein the heat-fusible organic resin film is an amorphous polyester film. 5. The pull-top can according to claim 1, wherein the lid further has an easily breakable organic resin film laminated on an inner surface thereof. 6. The easily breakable organic resin film on the inner surface of the lid has a large number of at least one hole selected from a heat-fusible organic resin film having a thickness of 6 to 15 μm or fine through holes and non-through holes. 6. The pull-top can according to claim 5, wherein the can is a porous heat-fusible organic resin film and is directly thermally laminated on the inner surface of the lid. 7. The pull-top can according to claim 6, wherein the heat-fusible organic resin film is an amorphous polyester film. 8. The easily breakable organic resin film on the inner surface of the lid is a porous organic resin film having a thickness of 5 to 12 μm or a large number of at least one hole selected from fine through holes and non-through holes. 6. The pull-top can according to claim 5, wherein the can is a resin film, and is thermally laminated on the inner surface of the lid via an adhesive layer. 9. Manufacture of a pull-top can having a can body having an open top and an inner surface laminated with an organic resin film, and an aluminum lid attached to the opening of the can body and having a pull-top mechanism. A hot melt resin is coated on one side of an aluminum thin plate to form a hot melt resin layer, and an organic resin film having a thickness of 5 to 12 μm is thermally laminated on the hot melt resin layer. A method for producing a pull-top can, comprising a step of forming a lid in which the organic resin film is located on the outer surface side by forming the lid. 10. Manufacture of a pull-top can having a can body having an open top and an inner surface laminated with an organic resin film, and an aluminum lid attached to the opening of the can body and having a pull-top mechanism. A porous organic resin having a hot melt resin on one side of an aluminum thin plate to form a hot melt resin layer, and the hot melt resin layer having a large number of at least one hole selected from fine through holes and non-through holes A method for producing a pull-top can, comprising a step of producing a lid in which the porous organic resin film is located on the outer surface side by performing outer shape processing and forming the pull-top mechanism after thermally laminating the film. . 11. The porous organic resin film according to claim 1, wherein
11. The pull-top according to claim 10, wherein at least one hole selected from a fine through-hole having an average opening diameter of 5 to 100 [mu] m and a non-through-hole is formed at a density of 500 / cm < ² > or more. Manufacturing method of cans. 12. The method according to claim 10, wherein the hot melt resin is a polyester-based resin. 13. A heat-fusible organic resin film having a thickness of 5 to 15 μm or at least one hole selected from fine through-holes and non-through-holes on the surface of the aluminum thin plate which is on the inner side in the state of the lid. The method for producing a pull-top can according to claim 10 or 11, wherein a large number of porous heat-fusible organic resin films of the above are directly thermally laminated. 14. A porous plate having a large number of at least one hole selected from an organic resin film having a thickness of 6 to 12 μm or fine through holes and non-through holes on a surface of the aluminum thin plate which is an inner surface side in the state of the lid. The method for producing a pull-top can according to claim 10 or 11, wherein the porous organic resin film is thermally laminated via an adhesive layer. 15. Manufacture of a pull-top can having a can body having an open top and an inner surface laminated with an organic resin film, and an aluminum lid attached to the opening of the can body and having a pull-top mechanism. In this case, a heat-sealable organic resin film is directly thermally laminated on one side of an aluminum thin plate, and a number of fine non-through holes are formed in the heat-sealable organic resin film.
A method for producing a pull-top can, comprising a step of producing a lid in which the porous heat-fusible organic resin film is located on the outer surface side by forming the pull-top mechanism. 16. Manufacture of a pull-top can having a can body having an open top and an inner surface laminated with an organic resin film, and an aluminum lid attached to the opening of the can body and having a pull-top mechanism. On the other hand, by thermally laminating an organic resin film on one side of an aluminum thin plate via an adhesive layer, forming a number of fine non-through holes in the organic resin film, performing external processing, and forming the pull-top mechanism. A method for producing a pull-top can, comprising a step of producing a lid in which the porous organic resin film is located on the outer surface side. 17. The method according to claim 17, wherein the perforations of the organic resin film are in a range of from 0.1 to 1.0.
The method for producing a pull-top can according to claim 15 or 16, wherein the fine non-through holes having an average opening diameter of 5 to 100 µm have a density of 500 or more / cm ² or more. 18. Further, an organic resin film is thermally laminated on the opposite side of the aluminum thin plate directly or via an adhesive layer, and simultaneously with the organic resin film thermally laminated on one side of the aluminum thin plate. Alternatively, after drilling a large number of fine non-through holes, the outer shape processing, forming the pull-top mechanism to form a lid body in which the porous organic resin film is located on the outer surface side and the inner surface side. The method for producing a pull-top can according to claim 15 or 16, wherein: 19. A heat-fusible organic resin film having a thickness of 5 to 15 μm thin or at least one hole selected from fine through holes and non-through holes on a surface of the aluminum thin plate which is an inner surface side in the state of the lid. 17. The method for producing a pull-top can according to claim 15 or 16, wherein a large number of porous heat-fusible organic resin films of the above are directly laminated. 20. A porous plate having a large number of at least one hole selected from an organic resin film having a thickness of 5 to 12 μm or a fine through hole and a non-through hole on a surface of the aluminum thin plate which is an inner surface side in a state of the lid. 17. The method for producing a pull-top can according to claim 15 or 16, wherein the high-quality organic resin film is thermally laminated via an adhesive layer.