JP2019131265A - Bottle can and method of producing thereof - Google Patents

Abstract

To provide a bottle can where not only a sealing property is high, but also damage of paint of an inner face of a can is few, and phenomena that splits occur in a curl portion at the time of forming are few, and the curl portion is not transformed easily, and the curl portion can be reduced in weight.SOLUTION: In a bottle can having a curl portion formed by folding back an opening end portion outward, in a vertical cross section along the can axis direction though a can axis, an inner connection curve portion, an upper end curve portion, an outer connection curve portion, and an outside curve portion of the curl portion are continuously arranged toward the outside from the inside by turns, when a height along the can axis direction of the curl portion is T mm, and a width along the radial direction is W mm, a ratio W/T is set to 0.8 or more and 1.0 or less, and a curvature radius of the outer connection curve portion is set to 0.5 mm or more and 0.8 mm or less.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a bottle can having a curled portion at an open end where a cap is sealed and a method for manufacturing the same.

  As a container filled with contents such as beverages, a metal cap (cap) liner was pressed against the curled portion formed at the open end of a bottle-shaped can (bottle can), and formed below the curled portion. A container in which a cap is screwed onto a threaded portion is known. In this type of bottle can, in order to ensure good sealing performance with the cap, the shape of the screw part and the curl part formed at the mouth part is important.

  For example, the threaded metal can disclosed in Patent Document 1 has an outer peripheral surface of a curl portion formed at the upper end of the mouth so that when the cap is screwed, the cap can be sealed by biting into a packing (liner) on the top surface of the cap. The crushing process for forming a plane part is given. By this crushing process, the top portion of the curled portion is formed into an arc surface that is slightly convex upward. This threaded metal can improves the sealing performance by solidifying the adhesion between the packing and the curled portion.

  On the other hand, in Patent Document 2, a curled portion of an outer winding in which a cut end portion is wound is formed by folding a portion of a predetermined length from the cut end portion of the opening portion one by one to the outside in order. doing. By this folding process, the entire curl portion is formed in a state of being crushed in the width direction in a state where the metal plates are overlapped in the width direction.

  In contrast to these technologies, Patent Document 3 discloses that the curled portion is formed into a vertically long oval shape in a longitudinal section so that the width of the curled portion is smaller than the height of the curled portion without performing curl crushing. The sealing performance is improved without deteriorating the plug performance. In the curled part of Patent Document 3, the radius of curvature R1 in the part from the upper part of the inner side surface of the curled part to the top of the curled part is about 0.9 mm, the radius of curvature R2 in the top part of the curled part is about 0.5 mm, The radius of curvature R3 in the portion that curls downward from the top of the curled portion to the maximum outer diameter portion of the curled portion is about 0.9 mm, and the radius of curvature R4 in the portion of the maximum outer diameter portion of the curled portion is about 0. The radius of curvature R5 at the portion that curls inward and downward from the maximum outer diameter portion of the curled portion to the tip of the curled portion is about 0.9 mm.

  Patent Document 4 describes that the outer diameter of an outer curl portion formed in a ring shape along the upper opening edge is 2.5 mm.

JP 2001-213417 A JP 2004-154862 A JP 2006-188279 A JP 2001-139053 A

  However, although the bottle can of patent document 1 has high sealing performance, since a curl part is crushed hard by crushing processing, the damage of a coating material is large. For this reason, the choice of the coating material used for the inner surface coating of a bottle can is limited. Depending on the choice of paint, the yield may be reduced due to paint damage.

  Further, in the folding molding of Patent Document 2, processing is severe and cracks are likely to occur in the curled portion. In addition, since the zenith portion has a sharp shape, there is a problem in sealing performance. Furthermore, since it folds in triple, many materials are used, and it is unsuitable for the weight reduction of a bottle can.

  The bottle can of Patent Document 3 has a large radius of curvature R3 of 0.9 mm from the top (curved portion) of the curled portion that curls outwardly from the top of the curled portion to the maximum outer diameter portion. Poor and difficult to seal. The radius of curvature R4 at the curled portion at the maximum outer diameter is small, but in order to obtain a wedge effect, the maximum outer diameter is too far from the top surface, so the cap squeezing amount becomes large and the bottle can lighter Unsuitable for conversion.

The curled portion described in Patent Document 4 has a diameter of 2.5 mm and a radius of curvature as large as 1.25 mm, and thus has a difficulty in sealing performance. Further, the curled portion is easily deformed.
Therefore, there is a need for a curl shape that has high sealing performance, little damage to the inner paint of the can, and can be reduced in weight.

  The present invention has been made in view of such circumstances. Not only is the sealing performance high, but the paint on the inner surface of the can is less damaged, the curl is less likely to crack during molding, and the curl is deformed. It is an object of the present invention to provide a curled portion that is difficult to reduce and can be reduced in weight.

  The bottle can of the present invention is a bottle can having a curled portion formed by folding the opening end portion outward, and the curled portion has an inner connecting curve in a longitudinal section along the can axis direction passing through the can axis. Part, upper end curved part, outer connecting curved part, and outer curved part are arranged from the inside toward the outside in this order, and the height along the can axis direction of the curl part is Tmm, and the width along the radial direction is Wmm. The ratio W / T is 0.8 or more and 1.0 or less, and the radius of curvature of the outer connecting curved portion is 0.5 mm or more and 0.8 mm or less.

  The curled portion has a width / height ratio W / T of 0.8 or more and 1.0 or less, resulting in a curled portion that is nearly circular. In addition, since the radius of curvature of the outer connecting curved portion is 0.5 mm or more and 0.8 mm or less so that the curled portion can be formed small, the curling portion can be easily bitten without the need for strong crushing. It is possible to obtain a bottle can that can be in close contact with the vicinity of the lower end portion thereof, has a large intimate range with the liner, and has good sealing performance. Further, since it is not necessary to perform a strong crushing process, damage to the inner surface paint during molding of the curled portion can be prevented, the selection of the can inner surface paint becomes wide, and it becomes possible to deal with various contents.

  In this case, if W / T is less than 0.8, the longitudinal cross section along the can axis direction of the curled portion becomes a shape that is vertically long and crushed in the radial direction. May occur. When W / T exceeds 1.0, the longitudinal cross section of the curled portion is conversely elongated and the curvature radius of the upper end curved portion and the outer connecting curved portion is increased, so that the cap bites into the liner becomes weaker, There is a risk of impairing the sealing performance. If the radius of curvature of the outer connecting curved portion is less than 0.5 mm, cracks may occur, and if it exceeds 0.8 mm, the sealing performance is poor.

  As a preferred embodiment of the bottle can of the present invention, the curled portion has a height T of 1.2 mm to 1.7 mm, a width W of 1.2 mm to 1.6 mm, and the inner connecting curved portion. The curvature radius may be 0.4 mm or more and 0.7 mm or less, and the curvature radius of the upper-end curved portion may be 0.7 mm or more and 1.2 mm or less.

  Since the curled portion is small and the radius of curvature of the upper end curved portion is also small, the cap bites more into the liner and the sealing performance is high. In addition, the small curled portion has a large deformation strength, and a stable sealing performance can be maintained. Further, the weight of the bottle can can be reduced.

  As a preferred embodiment of the bottle can of the present invention, an outer protrusion that protrudes radially outward by a connecting portion between the outer connecting curved portion and the outer curved portion is provided at a position where the curled portion has the maximum outer diameter. It is good to be formed.

Combined with the small curled portion, the maximum outer diameter portion is disposed at a position relatively close to the top surface, so that the wedge effect can be effectively exhibited.
In this case, as a preferred embodiment of the bottle can of the present invention, the radius of curvature of the outer protrusion is preferably 0.2 mm or more and 0.5 mm or less.

  As a preferred embodiment of the bottle can of the present invention, the outer curved portion is inclined in a direction gradually approaching the can axis as it goes downward in the can axis direction from the outer protrusion, and an inclination angle with respect to the can axis Is 10 ° or more and 30 ° or less, and the height from the top surface of the curled portion to the maximum outer diameter position of the outer protruding portion is 0.30 or more and 0.00 with respect to the height T of the curled portion. The ratio is preferably 45 or less.

The liner of the cap is in close contact with a wide range from the inner connecting curved portion to the upper end curved portion and the outer connecting curved portion, and the lifting of the liner due to an increase in internal pressure is restricted, and the liner is kept in close contact with the curled portion. . For this reason, the sealing performance can be maintained satisfactorily.
In this case, as a preferred embodiment of the bottle can of the present invention, the radius of curvature of the outer curved portion may be 1.5 mm or more and 2.0 mm or less.

As a preferred embodiment of the bottle can of the present invention, the outer curved portion may have a thickness of 0.320 mm or more and 0.355 mm or less.
Since the thickness of the curled portion can be reduced, the thickness of the can body before the curled portion is formed can be reduced, and the weight can be reduced.

  The bottle can manufacturing method of the present invention includes a DI step of forming a bottomed cylindrical DI can from an aluminum alloy plate having a plate thickness of 0.300 mm to 0.385 mm by squeezing and ironing, and the DI step after the DI step. A bottle necking step for reducing the diameter of the opening of the DI can, and a mouth forming step for forming a screw portion and a curl portion in the small diameter portion reduced in diameter by the bottle necking step. In the DI step, the DI can The thickness of the thick part on the opening side of the body of the body is 0.180 mm or more and 0.230 mm or less, and the thickness of the thin part on the bottom side of the body is 0.115 mm or more and 0.130 mm or less.

  Because the thickness of the thick part (so-called flange part) on the opening side of the body and the thickness of the thin part (so-called wall part) on the bottom side of the DI can are reduced, and an aluminum alloy plate with a small original plate thickness is used. The bottle can can be reduced in weight. And since the plate | board thickness is small, a small curl part can be shape | molded favorably, without producing a crack etc.

  According to the bottle can according to the present invention, the curl portion having high sealing performance, little damage to the paint on the inner surface of the can, less occurrence of cracks in the curl portion during molding, the curl portion is hardly deformed, and can be reduced in weight. Can be obtained.

It is a fragmentary sectional view which shows the bottle can and cap material of embodiment of this invention, and is the state before capping to the bottle can of a cap material. It is a longitudinal cross-sectional view along the can axial direction of the curl part of the bottle can of embodiment. It is a longitudinal cross-sectional view of the principal part which shows the state which attached the cap to the bottle can of embodiment. It is the elements on larger scale in FIG. It is a longitudinal cross-sectional view which shows a part of manufacturing process of a bottle can in order of (a)-(c). It is a longitudinal cross-sectional view which shows the shaping | molding process of a curl part.

Embodiments according to the present invention will be described below with reference to the drawings.
The bottle can 10 is made of a thin metal plate of an aluminum alloy, and as shown in FIG. 1, a bottomed cylindrical body 11 and a shoulder whose diameter is reduced to bend inward in the radial direction at the upper end of the body 11. It is formed by a portion 12, a tapered tubular portion 13 that gradually decreases in diameter from the shoulder portion 12 toward the upper side in the can axis direction, and a mouth portion 14 that continues to the upper end of the tapered tubular portion 13. The mouth portion 14 includes a bulging portion 15 formed at the upper end of the tapered cylindrical portion 13 via a neck portion 15 a, a screw portion 16 that continues to the upper end of the bulging portion 15, and an upper end from the upper end of the screw portion 16. It has a reduced diameter portion 17 that gradually decreases in diameter as it goes, and a curled portion 18 that is formed at the upper end of the reduced diameter portion 17 so that the opening end is folded outward in the radial direction. The cap member 3 is put on the mouth portion 14, the liner 40 on the inner surface of the top plate portion 31 of the cap material 3 is pressed against the curled portion 18, and the cylindrical skirt portion of the cap material 3 is along the screw portion 16. 33 is threaded, and the lower end portion of the skirt portion 33 is locked to the bulging portion 15, thereby forming the cap 30 and sealing the mouth portion 14. In the following description, the vertical direction is determined in the direction shown in FIG.

  The curled portion 18 of the bottle can 10 is formed continuously with the reduced diameter portion 17 formed above the screw portion 16 at a position below the can axis direction, and as shown in FIG. In the longitudinal cross section along the can axis direction, the inner curve is continuous to the upper end of the reduced diameter portion 17 and is bent from the diagonally lower side in the can axis direction toward the radially inner side and curved inward in the radial direction. The inner connecting curved portion 22, which is continuous to the upper end of the portion 21, the inner curved portion 21, and is curved so as to protrude obliquely upward in the can axis direction from the radially inner side; The upper end curved portion 23 that protrudes upward in the axial direction of the can and the outer peripheral end of the upper end curved portion 23 so as to be folded back from the radially inner side to the radially outer side. Outer bay that is curved so as to protrude outward and obliquely upward in the can axis direction And an outer curved portion 25 that is continuous with the lower end of the outer connecting curved portion 24 and that protrudes obliquely downward in the can axis direction outward in the radial direction, is formed in this order from the inner side toward the outer side. Yes. The upper end curved portion 23 constitutes the top surface of the curled portion 18, and the width (range indicated by X in FIG. 2) in the direction (radial direction) orthogonal to the can axis direction is formed constant in the circumferential direction. A substantially center position in the width direction is disposed at the uppermost end of the curled portion 18.

In this case, each connecting portion, that is, a connecting portion between the upper end of the reduced diameter portion 17 and the lower end of the inner curved portion 21, a connecting portion between the upper end of the inner curved portion 21 and the lower end of the inner connecting curved portion 22, and the inner connecting curved portion. 22, a connection portion between the upper end of the upper end bending portion 23 and the inner peripheral end of the upper end bending portion 23, a connection portion between the outer peripheral end of the upper end bending portion 23 and the upper end of the outer connection bending portion 24, and a lower end of the outer connection bending portion 24 and the outer bending portion 25. The connecting portion with the upper end is continuous with a smooth curved surface.
Further, the connecting portion between the lower end of the outer connecting curved portion 24 and the upper end of the outer curved portion 25 protrudes to protrude outward in the radial direction, and constitutes an outer protruding portion 26. The outer protruding portion 26 is a portion that smoothly connects the lower end of the outer connecting curved portion 24 and the upper end of the outer curved portion 25, and thus is curved in a slight range and has a width along the can axis direction. It is formed in a constant manner, and its substantially central position in the can axis direction protrudes most outward in the radial direction. The position of the protruding end (outer peripheral end) that protrudes most outward in the radial direction is the position that becomes the outermost diameter of the curled portion 18.

  The height along the can axis direction of the curled portion 18 (the height from the top surface of the upper end curved portion 23 to the lower end of the outer curved portion 25) is Tmm, and the width along the radial direction of the curled portion 18 (inner connected curved portion). The radial distance from the inner peripheral edge of 22 to the outer peripheral edge of the outer protrusion 26 is Wmm, and the height T is 1.2 mm or more and 1.7 mm or less, and the width W is 1.2 mm or more and 1.6 mm or less. The ratio W / T is 0.8 or more and 1.0 or less. Therefore, the overall cross-sectional shape is nearly circular.

The radius of curvature of each portion is the radius of curvature of the outer surface of the curled portion 18, and the radius of curvature r0 of the inner curved portion 21 is 1.2 mm or more and 2.3 mm or less, and the radius of curvature r1 of the inner connecting curved portion 22 is 0.1. 4 mm or more and 0.7 mm or less, the curvature radius r2 of the upper end curved portion 23 is 0.7 mm or more and 1.2 mm or less, the curvature radius r3 of the outer connecting curved portion 24 is 0.5 mm or more and 0.8 mm or less, and the curvature of the outer curved portion 25. The radius r4 is not less than 1.5 mm and not more than 2.0 mm. Further, the radius of curvature r5 of the outer protrusion 26 is not less than 0.2 mm and not more than 0.5 mm.
Further, as a whole, the outer curved portion 25 is inclined toward the direction (radially inward) gradually approaching the can shaft C as it goes downward from the outer protrusion 26 in the can shaft direction. The inclination angle θ with respect to C is set to 10 ° or more and 30 ° or less. The inclination angle θ of the outer curved portion 25 may be set as an angle formed by the tangent at the intermediate position in the length direction and the can axis C because the length of the outer curved portion 25 is short.

Further, the radius of curvature r5 of the outer protruding portion 26 is 0.2 mm or more and 0.5 mm or less, and the height Y from the top surface of the curled portion 18 to the outermost diameter position of the outer protruding portion 26 is the height of the curled portion 18. The thickness T is set to be a ratio of 0.30 or more and 0.45 or less.
Further, the thickness tc of the outer curved portion 25 is not less than 0.320 mm and not more than 0.355 mm. The inner curved portion 21, the inner connecting curved portion 22, the upper end curved portion 23, and the outer connecting curved portion 24 constituting the curled portion 18 other than the outer curved portion 25 have a thickness of 0.320 mm or more and 0.355 m or less. Is within the range.

  If the dimensions of the bottle can 10 other than the curled portion 18 are also described, the bottom plate 20 side of the trunk portion 11 is formed by an aluminum alloy plate having a former plate thickness t0 of 0.300 mm or more and 0.380 mm or less before molding. The thickness t1 of the thin portion 11a (a thin portion 53a of a DI can to be described later, so-called wall portion) is 0.115 mm or more and 0.130 mm or less, and the outer diameter of the body portion 11 is 64.24 mm or more and 68.24 mm or less. It is. Moreover, the outer diameter of the thread part 16 is 30.4 mm or more and 34.3 mm or less.

On the other hand, the cap 30 is made of a thin plate metal of aluminum or aluminum alloy. In the cap material 3 having a shape before being attached to the mouth portion 14 of the bottle can 10, the disc-shaped top plate portion 31 and the top plate portion 31 are formed. A skirt portion 33 extending vertically downward from the outer peripheral edge of the outer peripheral edge of the upper plate 31 and a liner 40 provided on the inner surface of the top plate portion 31. Further, the skirt portion 33 is provided with a knurled recess 34 for applying a frictional force to the hand at the time of opening and a vent hole 35 for releasing the internal pressure at the time of opening at a position close to the top plate portion 31 at the upper portion thereof. And the liner 40 is disposed between the upper piece and the top plate portion 31 to prevent the vent hole 35 from being pulled out. The
A slit 36 is intermittently formed in the lower end portion of the skirt portion 33 in the circumferential direction, and the skirt portion 33 is divided into a cylinder upper portion 33 a and a cylinder lower portion 33 b through the slit 36, and between the slits 36. A plurality of bridges 37 are formed to connect the cylinder upper part 33a and the cylinder lower part 33b.

  The liner 40 is entirely formed of a synthetic resin in a disc shape, and is installed to be freely rotatable with respect to the cap material 3. Specifically, the liner 40 is formed of an elastomer resin or the like and has a sealing layer 41 having a sealing function, and has a higher hardness than the sealing layer 41 and is formed of polypropylene or the like, and the top plate portion of the cap material 3. 31 and a slidable sliding layer 42 are provided. The sealing layer 41 has an outer diameter smaller than that of the sliding layer 42, and a thick seal portion 43 is formed in an annular shape on the outer peripheral portion. The seal portion 43 is a portion that is in close contact with the curled portion 18 of the bottle can 10.

Next, the manufacturing method of the bottle can 10 is demonstrated. The bottle can 10 includes a DI process for forming a bottomed cylindrical DI can by drawing and ironing from an aluminum alloy plate having a thickness t0 of 0.300 mm to 0.285 mm, and an opening of the DI can after the DI process. A bottle necking step for reducing the diameter of the portion, and a mouth forming step for forming a screw portion and a curl portion in the small diameter portion reduced in diameter by the bottle necking step.
These steps will be described in order.

<DI process>
First, the aluminum plate material is punched and drawn to form a shallow cup 51 having a relatively large diameter as shown in FIG. 5A (cup forming step). Next, the die 51 with a small outer diameter is used for the cup 51, and the drawing and ironing processing (DI processing) is performed again with a DI press to form a bottomed cylindrical body having a predetermined height, and the upper end is trimmed. Thus, the DI can 52 shown in FIG. 5B is manufactured.

  The DI can 52 obtained by this DI process has its bottom 20 shaped into the shape of the bottom 20 as the final bottle can 10, and the body 53 is formed in a cylindrical shape. The body 53 of the DI can 52 is formed with a thick portion from the opening end to a predetermined height, and is formed with a thin portion in the vicinity of the bottom 20 below it. The thick portion 53b near the opening end is referred to as a flange portion, and the thin portion 53a on the bottom 20 side is referred to as a wall portion.

In this DI process, the thickness t2 of the thick portion 53b of the body 53 is set to 0.180 mm or more and 0.230 mm or less, and the thickness t1 of the thin portion 53a on the bottom side (from the bottom portion 19 to the predetermined height). Is 0.115 mm or more and 0.130 mm or less. Further, the step in the thickness direction between the thick portion 53b and the thin portion 53a (difference (t1-t2) between the thickness t1 and the thickness t2) is preferably 0.100 mm or less.
If the thickness t1 of the thin wall portion 53a is less than 0.115 mm, the can body may buckle in the bottle necking process described later. In addition, if the thickness t2 of the thick wall portion 53b is less than 0.180 mm, the cap portion 14 of the bottle can 10 may be buckled or deformed when the cap is attached in the capping process after filling beverage or the like. There is a possibility that the torque at the time of resealing after the stopper is increased. Further, when the thickness t1 of the thin portion 53a exceeds 0.130 mm or the thickness t2 of the thick portion 53b exceeds 0.230 mm, the bottomed portion formed from the metal plate having the thin original plate thickness t0 as described above. There is a possibility that a necessary height cannot be obtained in the cylindrical body, or a trim margin is insufficient.
Furthermore, if the step between the thick portion 53b and the thin portion 53a exceeds 0.100 mm, there is a risk that a punching defect may occur in the DI process, or a barrel cut or buckling may occur. Further, in the bottle necking process, stress due to the molding load is concentrated on the stepped portion, which may cause buckling or deformation.

<Bottle necking process>
Next, the upper end portion of the DI can 52 is reduced in diameter by a bottle necking process, and as shown in FIG. 5C, the shoulder portion 12, the tapered cylindrical portion 13, and the small diameter portion 54 are formed on the cylindrical body portion 11. Form. In this bottle necking step, while using a plurality of necking dies (not shown) having different diameters of the molding part in order of increasing diameter, the necking die is used to reduce the diameter while pressing the upper end of the DI can 52 in the can axis direction. This is a so-called die necking process. Let the can obtained by this bottle necking process be the bottle necking can 55.

<Mouth molding process>
The mouth portion forming step is divided into a screw portion forming step and a curl portion forming step.
(Thread part forming process)
In the thread portion forming step, the neck portion 15a, the bulging portion 15 and the thread portion 16 are formed by processing the small diameter portion 54 of the bottle necking can 55 formed at the upper end portion in the bottle necking step. In this case, a cylindrical portion is formed by expanding the diameter of the portion that forms the screw portion 16 while leaving the upper end portion of the small diameter portion 54, and an inner piece is inserted into the cylindrical portion, and an outer piece is placed outside the cylindrical portion. (None of them are not shown in the figure) Press and place one part in the circumferential direction of the cylindrical part between these inner and outer pieces, and roll the inner and outer pieces around the cylindrical part in this state. By doing so, the threaded portion 16 is formed.
When this threaded portion 16 is molded, a small-diameter cylindrical portion 56 is formed above the threaded portion 16 via the reduced diameter portion 17 (see FIG. 6).

(Curl part molding process)
The curled portion forming step is performed on the upper portion of the screw portion 16 to form the curled portion 18.
The curl portion forming step will be described in more detail. For forming the curl portion 18, a forming tool having a folding die and a shaping die is used. The folding mold and the shaping mold are each formed in a roll shape, and are rotatably supported by a rotating body. In FIG. 6, the folding tool and the shaping mold are schematically illustrated as the molding tool 60 without being distinguished from each other, but actually, a plurality of folding molds and molding molds are alternately arranged. They are arranged at intervals in the circumferential direction.
Then, while both the folding mold and the shaping mold are swung along the cylindrical part 56, the cylindrical part 56 is pushed radially outward by pushing the upper part of the cylindrical part 56 downward from the upper end of the cylindrical part 56 by the folding mold. Then, the folded portion is folded back and pushed by a shaping mold so as to be shaped into a substantially circular curl shape. Thereby, a curled portion 18 continuous from the upper end of the reduced diameter portion 17 is formed.
It should be noted that the outer peripheral portion of the curled portion 18 may be slightly pressed inward in the radial direction to perform a slight crushing process.

The cap material 3 is put on the mouth portion 14 of the bottle can 10 manufactured in this way, is capped, and the cap material 3 is attached.
In this case, as shown by a chain line in FIG. 4, the top plate portion 31 of the cap material 3 is pressed in the can axis direction by the cap press 61, and the peripheral portion of the top plate portion 31 is drawn by the pressure block 62, The stepped portion 31a is formed, and the cap screw portion 38 is formed on the skirt portion 33 by the thread roller while pressing inwardly from the outside in the radial direction by the thread roller and the skirt roller (both not shown). The cylindrical lower portion 33b is wound around the bulging portion 15 and fixed by the skirt roller (see FIG. 3).
By capping in this way, the seal portion 43 of the sealing layer 41 of the liner 40 in the cap 30 is pressed against the curled portion 18 of the bottle can 10 to seal the inside.

  In the bottle can 10 configured as described above, the liner 40 of the cap 30 is in close contact with the upper end curved portion 23 of the curled portion 18 and the upper portion of the outer curved portion 25. In this case, the curled portion 18 is close to a circle with a ratio W / T of the width W to the height T of 0.8 or more and 1.0 or less, and has a small vertical cross-sectional shape. It is close in a wide range and has excellent sealing performance. In particular, since the radius of curvature r3 of the outer connecting curved portion 24 of the curled portion 18 is as small as 0.5 mm or more and 0.8 mm or less, the outer connecting curved portion 24 bites into the liner 40, and high sealing performance can be secured. it can. For this reason, even if it does not use strong crushing processing as shown in patent documents 1, since the bite into the liner 40 of the cap 30 is good and the sealing performance is excellent, damage to the inner surface paint is prevented when the curled portion 18 is formed. It is possible to use various types of inner surface paints, and the range of selection is widened, so that it is possible to deal with various contents.

When the W / T of the curled portion 18 is less than 0.8, the longitudinal section along the can axis direction of the curled portion 18 has a shape that is vertically long and crushed in the radial direction. There is a risk of cracking. When W / T exceeds 1.0, the longitudinal section of the curled portion 18 becomes a horizontally long shape, and the radii of curvature r2 and r3 of the upper end curved portion 23 and the outer connecting curved portion 24 are increased. The bite into 40 becomes weak, and there is a risk of impairing the sealing performance.
If the radius of curvature r3 of the outer connecting curved portion 24 is less than 0.5 mm, the processing becomes severe and cracking may occur, and if it exceeds 0.8 mm, the biting into the liner 40 becomes shallow and the sealing performance is poor. Further, since the outer protruding portion 26 (maximum outer diameter portion) having a small radius of curvature r5 continuous to the outer connecting curved portion 24 is disposed at a position relatively close to the top surface, the wedge effect on the liner 40 is also effectively exhibited. be able to.
Furthermore, such a small curled portion 18 has a large deformation strength and can maintain a stable sealing performance. Moreover, weight reduction of the bottle can 10 can also be achieved.

In addition, the present invention is not limited to the configuration of the above-described embodiment, and various modifications can be made in the detailed configuration without departing from the spirit of the present invention.
In FIG. 4, the seal portion 43 of the liner 40 is in close contact with the radially outer portion from the upper end curved portion 23, but the seal portion 43 is pressed to the upper portion of the inner connecting curved portion 22 on the radially inner side. Also good.

Next, examples of the present invention will be given to demonstrate the effects of the present invention. Thousands of bottomed cylindrical DI cans 52 with various changes in the original thickness t0 of the metal plate, the thickness t2 of the thick portion 53b of the DI can 52, the thickness t1 of the thin portion 53a and the step t2-t1. The moldability (DI moldability) with a DI press was confirmed. A straight punch was used for this DI molding. The dimension variation of the molded DI can was within 0.01 mm. Moreover, the mass of DI can was measured.
Of these, 100 DI cans 52 are formed into bottle necking cans 55 in the bottle necking process, the dimensions of each part are measured, the necking formability (BN formability) at that time is confirmed, and further in the capping process. After capping, the cap was opened, and the sealing performance was confirmed by measuring the reseal torque when the cap 3 was screwed into the mouth again and resealed, and a drop strength test was performed.
Sample 3 was formed with a curl portion having a substantially circular longitudinal section, and Samples 1, 2, 4, and 5 were deformed by applying a slight crushing process in the radial direction.
These results are shown in Table 1.

Here, the evaluation of the DI moldability is based on the case where all of the 1,000 DI cans to be molded could be DI press molded without causing buckling, deformation, torso cut, punch omission, etc. "If the DI press machine is stopped once due to buckling, deformation, torso cutting, etc., up to 1 out of 1000," △ "is indicated. If the DI press machine is stopped more than once," X "is indicated. It was.
The mass of the DI can is the average value of any 5 cans.

In addition, the evaluation of the BN moldability is performed by molding the shoulder, the tapered cylindrical portion, and the mouth in the bottle necking step and the mouth forming step in 100 DI cans that can be formed according to the predetermined dimensions in the DI step. By visually observing these, “◯” indicates that all can be molded to the predetermined dimensions without causing buckling, etc., and “△” indicates that buckling or the like has occurred up to one piece. A case where buckling or deformation occurred in more than one piece was designated as “x”.
In addition, the dimension of each part of a bottle can is an average value of arbitrary 10 cans.

  Furthermore, a cap material having a diameter of 33 mm having a top plate portion and a skirt portion is put on the mouth portions of ten bottle cans formed without causing buckling or the like in the bottle necking step and the mouth portion forming step. , By applying a vertical load (top pressure) in the can axis direction of 1000N with a cap made by CSI Japan Co., Ltd., forming the stepped portion by drawing the outer periphery of the top surface, roll set diameter 39.0 mm, thread roller A cap screw portion is formed so as to follow the screw portion by applying a load to the top surface side of the skirt portion in the radial direction with respect to the can shaft by a thread roller with a torque of 3.8 N · m. 0mm, skirt roller torque 3.0N ・ m, and the skirt roller is opposite the top of the skirt. It was tightened around the neck of the bulging portion the lower end (skirt winding) by applying a load in the radial direction inner side with respect to the can axis in the cylindrical lower portion.

  Here, the thread roller torque and the skirt roller torque are respectively the magnitude of the load applied to the skirt portion when the thread roller forms the cap screw portion on the cap material, and the skirt roller bulges the hem winding portion of the cap material. This is a substitute value of the magnitude of the load applied to the tail winding portion when tightening around the neck at the lower end of the portion, that is, the torque value of the drive arm for pressing each roller against the radially inner peripheral side with respect to the can shaft. In addition, the roll set diameter is the distance between the edges on the radially inner peripheral side of the facing rollers when these rollers are at the initial setting position farthest from the can axis (of the rollers facing each other around the can axis). From the roll set diameter, thread roller torque, and skirt roller torque, the tip load of each roller at the time of thread portion molding and tail winding can be calculated.

  As for sealing performance, the reseal torque is measured when the cap formed from the cap material in the capping step and attached to the mouth is once opened and then re-sealed by screwing into the mouth again. The case where the value of 20 N · cm or more was 0 can, “◯”, the case of 1 can was “Δ”, and the case of 2 cans or more was “x”. If the mouth portion buckles or deforms due to the molding load in the capping step, the frictional resistance between the screw portion of the can body and the cap screw portion of the cap increases, and the reseal torque also increases.

  In the drop strength test, 10 cans were dropped from various heights on a steel plate tilted 10 ° from a horizontal plane with the caps facing downward, and the presence or absence of leakage was confirmed. The presence or absence of leakage was measured by measuring the weight before and after the drop test, and when the difference was 20 mg or more, the leakage can was measured, and the drop height when one leakage can occurred was measured.

  These evaluation results are shown in Table 2.

  It can be seen that the bottle cans of Samples 1 to 5 have good DI moldability and necking moldability, and are excellent in sealing performance and drop strength. Also, no paint damage was observed.

DESCRIPTION OF SYMBOLS 3 Cap material 10 Bottle can 11 Trunk part 12 Shoulder part 13 Tapered cylinder part 14 Mouth part 15 Expansion part 15a Neck part 16 Screw part 17 Reduced diameter part 18 Curl part 30 Cap 21 Inner curved part 22 Inner connection curved part 23 Upper end curved part 24 outer connecting curved portion 25 outer curved portion 26 outer protruding portion 31 top plate portion 31a step portion 33 skirt portion 33a upper portion 33b lower portion 34 knurl recess 35 vent hole 36 slit 37 bridge 38 cap screw portion 40 liner 41 sealing layer 42 sliding Dynamic layer 43 Sealing part 52 DI can 53 Body 53a Thin part 53b Thick part 55 Bottle necking can 56 Tube part 62 Pressure block

Claims (8)

  A bottle can having a curled portion formed by folding an opening end portion outward, and in a longitudinal section along a can axis direction passing through the can shaft, the curled portion includes an inner connecting curved portion, an upper end curved portion, and an outer portion. The connecting curved portion and the outer curved portion are arranged in this order from the inner side to the outer side. When the height along the can axis direction of the curled portion is T mm and the width along the radial direction is W mm, the ratio W / T is The bottle can characterized by being 0.8 or more and 1.0 or less, and a curvature radius of the outer connecting curved portion being 0.5 mm or more and 0.8 mm or less.   The curled portion has a height T of 1.2 mm to 1.7 mm, a width W of 1.2 mm to 1.6 mm, and a curvature radius of the inner connecting curved portion of 0.4 mm to 0.7 mm. The bottle can according to claim 1, wherein a radius of curvature of the upper-end curved portion is 0.7 mm or more and 1.2 mm or less.   The outer projecting portion that protrudes radially outward is formed by a connecting portion between the outer connecting curved portion and the outer curved portion at a position where the curled portion has a maximum outer diameter. The bottle can according to 1 or 2.   The bottle can according to claim 3, wherein a radius of curvature of the outer protrusion is not less than 0.2 mm and not more than 0.5 mm.   The outer curved portion is inclined in a direction gradually approaching the can shaft as it goes downward in the can axis direction from the outer protrusion, and an inclination angle with respect to the can shaft is 10 ° or more and 30 ° or less, and The height from the top surface of the curled portion to the maximum outer diameter position of the outer protruding portion is a ratio of 0.30 to 0.45 with respect to the height T of the curled portion. The bottle can according to claim 3.   The bottle can according to any one of claims 1 to 5, wherein a radius of curvature of the outer curved portion is 1.5 mm or more and 2.0 mm or less.   The bottle can according to any one of claims 1 to 6, wherein a thickness of the outer curved portion is 0.320 mm or more and 0.355 mm or less.   A DI step of forming a bottomed cylindrical DI can from an aluminum alloy plate having a thickness of 0.300 mm to 0.385 mm by squeezing and ironing, and a bottle net for reducing the diameter of the opening of the DI can after the DI step And a mouth forming step of forming a screw portion and a curled portion in the small diameter portion reduced in diameter by the bottle necking step, and in the DI step, the thick portion on the opening side in the body of the DI can A thickness of 0.180 mm to 0.230 mm and a thickness of the thin portion on the bottom side of the body is set to 0.115 mm to 0.130 mm.

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