JP2021013959A - Bottle can - Google Patents

Abstract

To improve sealability of a bottle can with which a cap is screwed.SOLUTION: A bottle can has at an outer periphery part of a mouth part a curl part formed into a state that an opening end part is folded outside in a radial direction and a screw part formed at a lower position in a can axis direction of the curl part. The curl part has: an erect part which extends along the can axis direction above the can axis direction of the screw part in a vertical cross section going along the can axis direction; an inner bent part bent inward in the radial direction at an upper end of the erect part; and an apex folding part folded by a curved surface that follows the inner bent part and projects outward. The apex folding part protrudes both inward in the radial direction and outward in the radial direction from the erect part, and its folded lower end is folded into a smaller outer diameter than the maximum outer diameter of the apex folding part.SELECTED DRAWING: Figure 2

Description

The present invention relates to a method for manufacturing a bottle can having a threaded portion into which a cap is screwed.

As a container filled with contents such as beverages, a container in which a metal cap (cap) is screwed into a screw portion formed at an opening of a bottle-shaped can (bottle can) is known. In this type of bottle can, the shape of the threaded portion and the curled portion formed at the mouth portion is important in order to ensure good sealing with the cap.

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 portion so that the cap can be sealed by biting into the packing (liner) on the top surface of the cap when the cap is screwed. Is subjected to curl crushing processing to form a flat surface portion. By this curl crushing process, the top of the curl portion is formed into an arc surface that is slightly convex upward. This threaded metal can has improved sealing performance by making the adhesiveness between the packing and the curl portion firm.

Japanese Unexamined Patent Publication No. 2001-21317

However, with the thinning of the material, further improvement is required to improve the sealing property. The bottle can of Patent Document 1 has a high sealing property, but when the wall thickness of the bottle can is reduced or the hardness of the liner is reduced, the sealing property may be lowered. Especially for bottle cans with caps that are capped by filling thin bottle cans with the contents, the radius of curvature of the top of the curl that has been crushed becomes smaller, and the bite into the liner becomes larger than intended, so the liner runs out. In addition, it was found that a local thin-walled portion of the liner was formed and the liner was hardened after retort sterilization, so that the thin-walled portion was not sufficiently recovered and the sealing property was deteriorated.

The present invention has been made in view of such circumstances, and an object of the present invention is to further improve the sealing property of a bottle can into which a cap is screwed.

In the method for manufacturing a bottle can of the present invention, a curl portion formed on the outer peripheral portion of the mouth portion in a state where the opening end portion is folded outward in the radial direction and a screw formed at a position below the curl portion in the can axial direction. The outer peripheral surface of the curl portion has a portion, and the outer peripheral surface of the curl portion is folded back by a curved surface that is continuous from the upper end of the curl portion and is convex outward in the radial direction in a vertical cross section along the can axis direction. It has a folded portion, an outer bent portion continuous with the folded lower end of the zenith folded portion, and a curled end portion continuous from the outer bent portion, and the curled end portion is smaller than the maximum outer diameter of the zenith folded portion. A method of manufacturing bottle cans formed on the outer diameter.
An opening cylinder is formed at the opening end of the intermediate molded body to be the bottle can along the can axis direction, and the end of the opening cylinder is opened outward in the radial direction to form a folded portion. After that, by pressing the portion of the folded portion below the tip side in the can axis direction from the outside in the radial direction with a roll, the zenith folded portion is formed on the tip side in the can axis direction and pressed by the roll. The outer bent portion and the curled end portion are formed in the formed portion.
According to this manufacturing method, it can be manufactured by a simple process of folding back the end portion of the opening cylinder portion and then pressing the opening cylinder portion from the outside in the radial direction while leaving the tip side in the can axis direction.

According to this bottle can, when the cap is screwed, the liner of the cap is pressed and contacted with the upper surface of the zenith folded portion in the curl portion in the can axial direction. Also, during capping, the pressure block draws the peripheral edge of the top surface of the cap, so a load acts inward in the can axial direction and radial direction, but this load is received by the outer peripheral surface of the zenith folding portion. The outer peripheral surface of the zenith folded part also adheres to the liner.
Therefore, the liner can be in close contact with the liner from the upper surface to the outer peripheral surface of the zenith folded portion, and the sealing property can be improved.
The liner of the cap is a sheet-like one, which is a sheet-like one as a whole, but has an outer peripheral portion in contact with the curl portion formed in a thick seal portion, and two seal portions in contact with the curl portion. A form in which parallel ridges are formed along the circumferential direction and the curl portion is fitted between the two ridges can be applied.

The bottle can has a radius of curvature of 0.8 mm or more and 2.5 mm or less on the outer surface of the zenith folded portion.
It is possible to suppress the occurrence of a local thin-walled part of the liner due to the zenith folding part biting into the liner, and maintain the soundness of the liner for a long period of time.

A bottle can with a cap attached to a bottle can manufactured by the production method of the present invention has the bottle can and a cap attached to the bottle can, and the bottle can has an inner surface of the cap. A liner is provided in close contact with the curl portion of the above, and the liner is in close contact with the outer peripheral surface from the upper surface of the zenith folded portion.
Further, the liner may be in close contact with the outer peripheral surface of the outer bent portion and the curl end portion beyond the outer peripheral surface of the zenith folded portion.
Further, the liner is formed with inner ridges inserted inside the curl portion in the radial direction and outer ridges arranged radially outside the curl portion, and these inner ridges and outer ridges are formed. Is extended to a position below the zenith folded portion, and the lower ends of both convex stripes may be arranged at intervals smaller than the width in the direction orthogonal to the can axis direction of the zenith folded portion.

In this bottle can with a cap, the zenith folded portion at the curl portion of the bottle can is fitted between the inner and outer ridges of the liner of the cap, and the zenith folded portion is fitted from the inner peripheral surface to the upper surface and the outer peripheral surface of the zenith folded portion. It adheres to the liner up to the point and can ensure high sealing performance.

According to the bottle can according to the present invention, the sealing property between the curl portion formed in the mouth portion and the cap can be improved.

It is a partial cross-sectional view which shows the bottle can and the cap material of this invention, and is the state before the cap material is capped in the bottle can. (A) is a state before capping, and (b) is a semi-cross-sectional view near the mouth showing the state after capping. It is an enlarged cross-sectional view around the curl portion shown in FIG. 2 (b). It is a vertical cross-sectional view which shows the first half part of the manufacturing process of a bottle can in the order of (a)-(c). It is a vertical cross-sectional view which shows the latter half part of the manufacturing process of a bottle can in the order of (a)-(c). It is an enlarged vertical sectional view which shows the molding process of a curl part in the order of (a) and (b). It is a front view which shows typically the bottle can manufacturing apparatus. It is sectional drawing which follows the AA line of FIG. It is a schematic diagram which shows the main part of a capping device. It is the one to which the cap of the modification is applied, (a) is the state before capping, (b) is the semi-cross-sectional view near the mouth which shows the state after capping. It is an enlarged cross-sectional view around the curl part shown in FIG. 10B.

Hereinafter, embodiments according to the present invention will be described with reference to the drawings.
The bottle can 10 is made of a thin metal plate of aluminum or an aluminum alloy, and as shown in FIG. 1, has a bottomed cylindrical body portion 11 and a diameter reduced so as to bend inward in the radial direction at the upper end of the body portion 11. It is formed of a shoulder portion 12, a tapered cylinder portion 13 whose diameter is gradually reduced upward in the can axis direction from the shoulder portion 12, and a mouth portion 14 continuous with the upper end of the tapered cylinder portion 13. Further, the mouth portion 14 has a bulging portion 15 formed at the upper end of the tapered tubular portion 13, a threaded portion 16 continuous with the upper end of the bulging portion 15, and gradually contracting upward from the upper end of the threaded portion 16. It has a reduced diameter portion 17 having a diameter, and a curled portion 18 formed at the upper end of the reduced diameter portion 17 so that the opening end portion is folded outward in the radial direction. Then, the mouth portion 14 is covered with the cap material 3 as shown in FIG. 2A, the liner 40 on the inner surface of the top surface portion 31 of the cap material 3 is pressed against the curl portion 18, and the cap is capped along the screw portion 16. The cylindrical skirt portion 33 of the material 3 is screwed, and the lower end portion of the skirt portion 33 is locked to the bulging portion 15, so that the cap 30 is formed and the mouth portion 14 is sealed (FIG. 2). (B) and FIG. 3). In the following description, the vertical direction shall be determined in the direction shown in FIG.

The curl portion 18 is continuously formed in the reduced diameter portion 17 formed at the lower position in the can axial direction, and as shown in FIGS. 2 and 3, the curled portion 18 has a reduced diameter in the vertical cross section along the can axial direction. An upright portion 21 that bends at the upper end of the portion 17 and extends along the can axis direction, an inner bent portion 22 that bends inward in the radial direction at the upper end of the upright portion 21, and a continuous outward bending portion 22. A zenith folded portion 23 that is folded back by a curved surface that is convex toward the can, an outer bent portion 24 that bends in the can axis direction at the folded lower end of the zenith folded portion 23, and an outer bent portion 24 that extends in the can axis direction. It has a curl end portion 25 facing the outer peripheral surface of the upright portion 21.

In this case, as shown in FIG. 6B, the zenith folded portion 23 is formed so that the lower end of the folded portion (at a position substantially the same as the outer bent portion 24) has an outer diameter D2 smaller than the maximum outer diameter D1 of the zenith folded portion 23. (Substantially, it is also the outer diameter D2 of the curl end 25). Further, the width (distance from the inner peripheral edge of the zenith folding portion 23 to the outer peripheral edge) W1 in the direction orthogonal to the can axis direction is the radial distance W2 from the inner peripheral surface of the upright portion 21 to the outer peripheral surface of the curl end portion 25. Is formed larger than. Therefore, the inner peripheral portion of the zenith folded portion 23 protrudes inward in the radial direction from the inner peripheral surface of the upright portion 21, and the outer peripheral portion of the zenith folded portion 23 protrudes outward in the radial direction from the outer peripheral surface of the curl end portion 25. ing. The zenith folded portion 23 is formed so that the radius of curvature R of its outer surface is 0.8 mm or more and 2.5 mm or less. The radius of curvature R of the upper surface of the zenith folding portion 23 may be a single radius of curvature, or arcs having a plurality of different radii of curvature may be continuous. Further, although some tubular surfaces 23a and 23b are formed on the inner peripheral surface and the outer peripheral surface of the zenith folded portion 23, the tubular surfaces 23a and 23b are not formed, and the curved surface having the radius of curvature R described above as a whole is not present. It may be formed in.

In the bottle can 10 having such a shape, other dimensions are not necessarily limited, but for example, the thickness of the body portion 11 is made of an aluminum alloy plate having a base plate thickness of 0.300 mm or more and 0.380 mm or less. (Wall thickness) is 0.110 mm or more and 0.125 mm or less, the thickness from the screw portion 16 to the curl portion 18 is 0.210 mm or more and 0.230 mm or less, and the outer diameter of the curl portion 18 (maximum outer diameter of the zenith folded portion 23). ) D1 is formed to be 32.0 mm or more and 35.0 mm or less, the width W1 is formed to be 1.5 mm or more and 3.0 mm or less, and the height H of the zenith folding portion 23 in the can axis direction is formed to be 2.0 mm or more and 4.0 mm or less. ..

On the other hand, the cap 30 is made of a thin metal plate of aluminum or an aluminum alloy, and the cap material 3 having a shape before being attached to the mouth portion 14 of the bottle can 10 is a circle as shown in FIGS. 1 and 2 (a). It has a plate-shaped top surface portion 31, a skirt portion 33 extending vertically downward from the outer peripheral edge of the top surface portion 31, and a liner 40 provided on the inner surface of the top surface portion 31. Further, in the skirt portion 33, a knurl 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 are provided in the circumferential direction at a position close to the top surface portion 31 above the skirt portion 33. A plurality of them are formed, and the upper piece 35a of the vent hole 35 is formed in a state of being pushed inward in the radial direction, so that the liner 40 is arranged between the upper piece 35a and the top surface portion 31 and is prevented from coming off. To.
A slit 36 is formed intermittently in the circumferential direction at the lower end of the skirt portion 33, and the skirt portion 33 is divided into a cylinder upper portion 33a and a cylinder lower portion 33b through the slit 36, and between the slits 36. The upper part of the cylinder 33a and the lower part of the cylinder 33b are connected by a plurality of bridges 37 formed in the above.

The liner 40 is entirely made of synthetic resin and is formed in a disk shape, and is freely rotatably installed on the cap material 3. Specifically, the liner 40 has a sealing layer 41 formed of an elastomer resin or the like and having a sealing function, and has a hardness higher than that of the sealing layer 41, and is formed of polypropylene or the like and has a top surface portion 31 of the cap material 3. And a slidable sliding layer 42 are laminated. The outer diameter of the sealing layer 41 is smaller than that of the sliding layer 42, and a thick sealing portion 43 is formed in an annular shape on the outer peripheral portion. The seal portion 43 is a portion that comes into close contact with the curl portion 18 of the bottle can 10.

In order to manufacture the bottle can 10, first, an aluminum plate material is punched out and drawn to form a relatively large diameter and shallow cup 1 as shown in FIG. 4A, and then the cup 1 is recombined. Drawing and ironing (DI processing) are added to form a tubular body 2 having a predetermined height as shown in FIG. 4 (b), and the upper end thereof is trimmed and aligned. By this DI processing, the bottom portion of the tubular body 2 is formed into the shape of the bottom portion 10a as the final bottle can 10.

Next, the bottle can 10 is manufactured by the bottle can manufacturing apparatus 50 shown in FIGS. 7 and 8. The bottle can manufacturing apparatus 50 will be described below. The bottle can manufacturing apparatus 50 is for processing the tubular body 2 formed as described above into a bottle can 10 having a final shape, and the shape of the can changes according to the progress of the processing. However, in the following, when the shape of the can is not particularly limited between the cylinder 2 and the bottle can 10, the intermediate molded body 4 will be described.

The bottle can manufacturing apparatus 50 includes a work holding portion 51 that holds a plurality of intermediate molded bodies 4 in a horizontally arranged can axis direction, and a plurality of molding tools 52 that perform various molding processes on the intermediate molded bodies 4. A tool holding unit 53 for holding the tool and a driving unit 54 for driving both the holding units 51 and 53 are provided. The work holding side of the work holding portion 51 that holds the intermediate molded body 4 and the tool holding side of the tool holding portion 53 that holds the molding tool 52 are arranged so as to face each other.

The work holding portion 51 has a configuration in which a plurality of holding devices 57 for holding the intermediate molded body 4 are arranged in an annular shape along the circumferential direction on the surface of the disk 56 supported by the support shaft 55 facing the tool holding portion 53. Has been done. The disk 56 is intermittently rotated around the support shaft 55 by the drive unit 54, so that the bottom portion of the intermediate molded body 4 supplied from the supply unit 58 via the supply side star wheel 59 is set to the holding device 57 by 1. Each piece is held and conveyed in the circumferential direction of the disk 56. The intermediate molded body 4 is molded by each molding tool 52 of the tool holding portion 53 during transportation by the disk 56, and then is sequentially discharged to the discharge portion 61 via the discharge side star wheel 60 as a bottle can 10 after molding. ..

In the tool holding portion 53, a plurality of various molding tools 52 are arranged in an annular shape along the circumferential direction on the surface of the disk 63 supported by the support shaft 62 facing the work holding portion 51, and the disk 63 is supported by the driving unit 54. It is configured to move forward and backward in the axial direction of the shaft 62. The support shaft 62 is provided coaxially inside the support shaft 55.

The tool holding portion 53 is formed with a plurality of necking molds for reducing the diameter (neck-in processing) of the opening of the intermediate molded body 4, a screw forming tool for forming the screw portion, and a curl portion 18. A plurality of molding tools 52 for performing machining according to each machining stage, such as the curl portion molding tool of the above, are provided. These molding tools 52 are arranged in a ring shape on the disk 63 in the order of processes and arranged in the circumferential direction.

The intermittent rotation stop position of the work holding portion 51 (disk 56) centered on the axis of the support shaft 55 is such that the can shaft of each intermediate molded body 4 with the opening facing the tool holding portion 53 side is each molding tool. It is set so as to coincide with the central axis of 52. Then, by the intermittent rotation of the disk 56 by the drive unit 54, each intermediate molded body 4 is rotationally moved to a position facing each molding tool 52 for the next process, and the next stage of processing is performed.

That is, when the tool holding portion 53 advances and the work holding portion 51 and the tool holding portion 53 approach each other, each molding tool 52 performs processing according to each process on the intermediate molded body 4, and both holding portions 51. When the parts and 53 are separated from each other, the work holding portion 51 is rotationally moved so that the molding tool 52 of the next step faces each intermediate molded body 4. In this way, the shoulder portion 12, the tapered cylinder portion 13, and the mouth portion 14 are sequentially formed on the intermediate molded body 4 by repeating the operations of the two holding portions 51 and 53 processing in close proximity to each other, separating and rotating. The bottle can 10 is formed.

In this case, first, as shown in FIG. 4C, an intermediate molded body 4 having a straight cylindrical portion 5 at the upper end portion is formed.
Then, as shown in FIG. 5A, the diameter of the cylindrical portion 5 is expanded again from a position slightly above the upper end of the tapered tubular portion 13, and then the diameter of the upper portion is reduced again except for the lower end portion of the expanded portion. The tubular portion 6 before screwing is formed by such means. Next, the tubular portion 6 is threaded to form the threaded portion 16 as shown in FIG. 5 (b). In the state where the threaded portion 16 is formed, on the threaded portion 16, a diameter-reduced portion 17 that gradually reduces in diameter as it goes upward, and a straight opening tube portion 8 that is connected to the threaded portion 16 and follows the can axis direction It is formed.
Then, the opening cylinder portion 8 is folded outward in the radial direction to form a folded portion 19 whose tip is directed toward the bottom of the can (FIG. 5 (c)).

The processing of the folded-back portion 19 is performed by two steps of a folding step of folding back the opening cylinder portion 8 so as to make a U-turn and a zenith folding portion forming step of forming the zenith folding portion 23 from the folded-back portion formed thereby. ..
First, in the folding step, the expanding die 52A and the folding die 52B shown by the alternate long and short dash line in FIG. 5B are used as the forming tool 52. Each of the expansion die 52A and the folding die 52B is formed in a roll shape, is rotatable as shown by an arrow, and is supported so as to be rotatable along the circumferential direction of the opening cylinder portion 8. By pressing the opening cylinder 8 toward the bottom of the can while turning, the opening cylinder 8 is opened outward by the expanding die 52A, and then folded back by the folding die 52B.

FIG. 6A shows the folded-back portion 19 formed in this way, in which the tip portion in the can axial direction is formed in an arc surface whose tip portion is convex upward, and the remaining portion of the opening cylinder portion 8 is formed below the arc surface. The portion and the end portion 19a of the folded portion 19 are arranged substantially in parallel. The arc surface that is convex upward at the tip portion in the can axis direction forms the upper surface of the zenith folded portion 23.
Next, in the zenith folding portion forming step, as the molding tool 52, as shown by the alternate long and short dash line in FIG. 6A, the inner roll 52C inserted into the opening formed by the folding portion 19 and the folding portion 19 The folded-back portion 19 is processed by using the outer roll 52D arranged on the outer side in the radial direction of the above. Specifically, by bringing both rolls 52C and 52B close to each other, the lower end portion of the opening cylinder portion 8 and the lower end portion 19a of the folded portion 19 remaining below the folded portion 19 are crushed from both sides in the plate thickness direction. As shown in FIG. 6B, the zenith folded-back portion 23 is formed above the sandwiched portion by pressing and sandwiching the zenith. The inner bent portion 22 and the upright portion 21 are formed in the portion pressed by the inner roll, and the outer bent portion 24 and the curl end portion 25 are formed in the portion pressed by the outer roll. As a result, the molding of the curl portion 18 is completed. The lower end of the curl end portion 25 is formed in a slightly bent state due to molding marks when the tip end of the opening cylinder portion 8 is expanded by the expansion mold 52A described above.

In order to attach the cap material 3 to the mouth portion 14 of the bottle can 10 manufactured in this manner and perform the capping process, for example, a capping device provided with a plurality of capping heads 70 as shown in FIG. 9 is used. Then, the cap material 3 is adhered to the bottle can 10 by the capping head 70.
The capping head 70 includes a pressure block 62 having a cap retainer 61, a first roll 63 as an RO roll (roll-on-roll), and a second roll 64 as a PP roll (pilfer-proof roll). .. The lower end of the pressure block 62 is formed in a tubular shape, and can move relative to the cap retainer 61 arranged inside the pressure block 62 in the can axis direction, and a spring 65 is provided between the pressure block 62 and the cap retainer 61. ing. Further, the first roll 63 and the second roll 64 are supported so as to be rotatable around the pressure block 62 and movable in the can axis direction.

Then, with the cap material 3 covering the mouth portion 14 of the bottle can 10, the cap retainer 61 presses the top surface portion 31 of the cap material 3 of the cap material 3, and in that state, the pressure block 62 is placed on the outer peripheral portion of the top surface portion 31. The step portion 31a is formed by performing draw forming. Further, the cap screw portion 38 is formed on the cap material 3 by the first roll 63, and the lower portion 33b of the cylinder is wound around the bulging portion 15 and fixed by the second roll 64.
By being capped in this way, the liner 40 in the cap 30 is pressed against the mouth 14 of the bottle can 10 to seal the inside.

In the bottle can 10 configured as described above, the entire outer surface of the zenith folding portion 23 in the curl portion 18 is formed on a curved surface that is convex outward, so that the load in the can axis direction at the time of cappings is formed. As a result, the liner 40 is brought into close contact with the curved upper surface of the zenith folded portion 23, and the peripheral edge of the top surface 31 of the cap 30 is drawn by the pressure block 62, so that the liner 40 is also drawn on the outer peripheral surface of the zenith folded portion 23. Is in close contact. Since the outer surface of the zenith folded portion 23 is formed by a curved surface, the curved surface bites into the liner 40, but since the radius of curvature R is formed to be 0.8 mm or more and 2.5 mm or less, it depends on the bite. The generation of locally thin-walled portions of the liner 40 is suppressed, and the soundness of the liner 40 can be maintained for a long period of time.

In this way, since the liner 40 is in close contact with the liner 40 in a wide range from the upper surface to the outer peripheral surface of the zenith folding portion 23, the pressure of the contents in the positive pressure state (beverage containing carbon dioxide gas, beverage filled with nitrogen gas, etc.) is increased. Even if the top surface portion 31 of the cap 30 rises and deforms in the direction of bulging upward in the can axis direction together with the liner 40, the liner 40 is caught on the outer peripheral surface of the zenith folding portion 23, and the liner 40 is lifted due to the increase in internal pressure. It is regulated and the state of close contact of the outer peripheral surface of the zenith folded portion 23 is maintained. Therefore, good sealing performance can be maintained.

The bottle can configured as described above can be applied to a cap 30 having a liner 44 molded as shown in FIGS. 10 and 11 in addition to the above-mentioned cap having a substantially sheet-shaped liner. it can. In the following description and FIGS. 10 and 11, the same reference numerals are given to the parts common to the above-described embodiment, and the description thereof will be omitted.
10A and 10B are a vertical cross-sectional view of a state in which the cap material 3 is covered with the bottle can 10, and FIG. 10B is a vertical cross-sectional view of the state after the cap 30 is wound around the bottle can 10.
In the liner 44, the inner ridges 46 and the outer ridges 47 are formed in a concentric double ring shape on the outer peripheral portion of the sealing layer 45, and a concave groove portion 48 is formed between the two ridges 46 and 47. The seal portion 49 composed of the inner ridge 46, the outer ridge 47, and the concave groove portion 48 is formed in an annular shape.

When the cap material 3 is put on the curl portion 18 of the bottle can 10, the curl portion 18 is inserted into the concave groove portion 48 of the seal portion 49 as shown in FIG. 10A. Then, as shown in FIGS. 10B and 11, the bottom surface of the concave groove portion 48 is in close contact with the upper surface of the zenith folded portion 23, and the pressure block 62 causes the outer peripheral side of the top surface portion 31 of the cap material 3 to be in the can bottom direction. By drawing while being pressed against, a stepped portion 31a is formed on the peripheral edge portion of the top surface portion 31, and the outer ridge 47 of the liner 44 is pressed against the outer peripheral surface of the zenith folded portion 23. Further, as the outer ridge 47 is deformed, the inner ridge 46 is attracted to the curl portion 18, and the outer peripheral surface of the inner ridge 46 comes into close contact with the inner peripheral surface of the zenith folded portion 23.

In this case, the length L of the double ridges 46 and 47 in the can axis direction is larger than the height H of the zenith folded portion 23 (see FIG. 6B), and is between the inner surfaces of the double ridges 46 and 47. The distance, that is, the width W3 in the direction orthogonal to the can axis direction of the concave groove portion 48 is set to be the same as or smaller than the width W1 of the zenith folding portion 23 (see FIG. 6B).
By setting in this way, when the zenith folding portion 23 is fitted in the concave groove portion 48, the distance between the two convex stripes 46 and 47 is expanded at the initial stage of the fitting, but the zenith folding portion 23 When the upper surface bites into the bottom surface of the concave groove portion 48, the lower ends of the double ridges 46 and 47 that reach below the zenith folding portion 23 tend to approach each other due to the pressing force of the capping and the elastic force of the seal portion 49. The interval is narrowed. Further, a drawing action by the pressure block 62 also occurs at the peripheral edge portion 31a of the top surface portion 31 of the cap 3. Therefore, as shown in FIGS. 10B and 11, from the downward curved surface of the zenith folded portion 23 to the inner peripheral surface of the inner bent portion 22, the outer peripheral surface of the outer bent portion 24, and further upright below them. The ridges 46 and 47 are also in close contact with the inner peripheral surface of the portion 21 and the outer peripheral surface of the curl end portion 47. As a result, in the bottle can 10, the double ridges 46, 47 and the concave groove portion 48 are formed by applying the cap 30 to the cap 30 provided with the liner 44 having the double ridges 46, 47 and the concave groove portion 48. It adheres to a wide area of the inner surface, and high sealing performance can be obtained.

3 Cap material 4 Intermediate molded body 5 Cylindrical part 6 Cylindrical part 8 Small cylinder part 10 Bottle can 14 Mouth part 15 Swelling part 16 Threaded part 17 Reduced diameter part 18 Curled part 21 Upright part 22 Inner bent part 23 Climax folded part 23a , 23b Cylindrical surface 24 Outer bending part 25 Curl end part 30 Cap 31 Top surface part 31a Step part 33 Skirt part 33a Cylinder upper part 33b Cylinder lower part 34 Nar recess 35 Vent hole 35a Upper piece 36 Slit 37 Bridge 38 Cap screw part 40, 44 Liner 41, 45 Sealing layer 42 Sliding layer 43, 49 Sealing part 46 Inner ridge 47 Outer ridge 48 Concave groove 52A Expansion mold 52B Folding mold 52C Inner roll 52D Outer roll 62 Pressure block 63 First roll 64 2nd roll 65 Spring 70 Capping head

The present invention relates to a bottle can having a threaded portion which cap is screwed.

The bottle can of the present invention has a curl portion formed on the outer peripheral portion of the mouth portion in a state where the opening end portion is folded outward in the radial direction, and a screw portion formed at a position below the curl portion in the can axial direction. Have and
The outer peripheral surface of the curl portion is a zenith folded portion formed by a curved surface that is continuously convex from the upper end of the curl portion in the radial direction in a vertical cross section along the can axis direction, and the zenith. The zenith folded portion has an outer bent portion that is continuous with the lower end of the folded portion and bends inward in the radial direction and a curl end portion that is continuous from the outer bent portion , and the maximum outer diameter D1 of the zenith folded portion is 32. It is 0.0 mm or more and 35.0 mm or less, and the curl end portion is formed to have an outer diameter smaller than the maximum outer diameter of the zenith folded portion , and the outer peripheral surface of the curl end portion is convex outward. A bottle can characterized by being bent in a shape.
In order to manufacture this bottle can, an opening cylinder portion is formed at the opening end portion of the intermediate molded body to be the bottle can along the can axis direction, and the end portion of the opening cylinder portion is outward in the radial direction. After forming a folded portion that is opened and folded, the portion below the tip side in the can axis direction of the folded portion is pressed from the outside in the radial direction with a roll, so that the zenith folded portion is on the tip side in the can axis direction. And the outer bent portion and the curl end portion are formed in the portion pressed by the roll.
According to this manufacturing method, it can be manufactured by a simple process of folding back the end portion of the opening cylinder portion and then pressing the opening cylinder portion from the outside in the radial direction while leaving the tip side in the can axis direction.

Bottle cans in the bottle with the cap formed by attaching the cap can have said bottle can, and a cap attached to the bottle can closely to the curl portion of the bottle can in the inner surface of the cap liner Is provided, and the liner is in close contact with the outer peripheral surface from the upper surface of the zenith folded portion.
Further, the liner may be in close contact with the outer peripheral surface of the outer bent portion and the curl end portion beyond the outer peripheral surface of the zenith folded portion.
Further, the liner is formed with inner ridges inserted inside the curl portion in the radial direction and outer ridges arranged radially outside the curl portion, and these inner ridges and outer ridges are formed. Is extended to a position below the zenith folded portion, and the lower ends of both convex stripes may be arranged at intervals smaller than the width in the direction orthogonal to the can axis direction of the zenith folded portion.

Claims (1)

The outer peripheral portion of the mouth portion has a curl portion formed in a state where the opening end portion is folded outward in the radial direction, and a screw portion formed at a position downward in the can axis direction of the curl portion.
The outer peripheral surface of the curl portion is a zenith folded portion formed by a curved surface that is continuously convex from the upper end of the curl portion in the radial direction in a vertical cross section along the can axis direction, and the zenith. It has an outer bent portion that is continuous with the folded lower end of the folded portion and a curl end that is continuous from the outer bent portion.
The curl end is a method for manufacturing a bottle can having an outer diameter smaller than the maximum outer diameter of the zenith folded portion.
An opening cylinder is formed at the opening end of the intermediate molded body to be the bottle can along the can axis direction, and the end of the opening cylinder is opened outward in the radial direction to form a folded portion. Then, by pressing the portion of the folded portion below the tip side in the can axis direction from the outside in the radial direction with a roll, the zenith folded portion is formed on the tip side in the can axis direction and pressed by the roll. A method for producing a bottle can, which comprises forming the outer bent portion and the curled end portion on the formed portion.

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