JP7082929B2 - Bottle can with cap and its sealing method - Google Patents

Description

The present invention relates to a capped bottle can in which a cap is attached to the mouth of a bottle can for beverages and the like and sealed, and a method for sealing the bottle can.

As a cap that seals the mouth of a bottle-shaped can (bottle can), the gas inside the bottle can is released when the internal pressure rises excessively due to secondary fermentation of the contents after re-plugging the cap once opened. A cap having a so-called explosion-proof function is known, which prevents the bottle can from bursting and the cap from popping out by lowering the internal pressure.
For example, the cap disclosed in Patent Document 1 has a linear knurl slit (vent hole) in which an opening is formed in a knurl recess provided in the knurl of the cap to release internal pressure at the time of opening, and a knurl non-forming region of a cylindrical portion. It is formed and arranged below the nal slit, and has a linear weakening line that opens when a predetermined internal pressure is reached with the bottle can sealed, and this weakening line has a predetermined internal pressure opening value. It can be opened to release the internal gas and release the internal pressure. In this case, as the weakening line, one by a plurality of intermittently formed slits and one by one long slit are disclosed.

Japanese Unexamined Patent Publication No. 2008-63001

In this way, conventionally, when the internal pressure inside the bottle can rises excessively while the cap is attached to the bottle can, the internal pressure is discharged to the outside to prevent the cap from jumping. There is. However, since the weakened portion for explosion prevention opens when a predetermined internal pressure is reached, it is necessary to prevent the weakened portion from opening carelessly except when the internal pressure rises excessively.

The present invention has been made in view of such circumstances, and an object of the present invention is to prevent the occurrence of a phenomenon in which a weakened portion having an explosion-proof function is inadvertently opened.

The bottle can with a cap of the present invention is a bottle can with a cap attached to a male screw portion formed at the mouth of the bottle can and tightly closed, and the cap has a vent hole for releasing internal pressure at the time of opening. A linear weakening line along the circumferential direction that opens when a predetermined internal pressure is reached is provided, and the center position of the weakening line in the length direction is from the opening end of the mouth portion to the thread of the male thread portion. It is provided so as to avoid a region where the distance to the ridgeline is less than 4.90 mm.

In the region where the distance from the open end of the mouth to the ridge of the thread of the male thread is short, the distance between the peripheral wall of the cap and the outer surface of the mouth of the bottle can is large, and when a weakening line is placed in such a region, There is a risk of inadvertent opening in the event of a drop impact. Therefore, the occurrence of leakage can be suppressed by providing the center position of the weakening line in the length direction avoiding a region where the distance from the opening end of the mouth portion to the ridgeline of the screw thread is less than 4.90 mm. ..
Especially in bottle cans where the start end of the male thread cannot be clearly identified and the incomplete thread is formed long in the circumferential direction until the thread reaches a certain height, the position of the weakening line is determined. It is valid.

In the bottle can with a cap of the present invention, the region where the distance is less than 4.90 mm is preferably from the start end portion of the male threaded portion to a position advanced by 80 ° in the circumferential direction along the male threaded portion, and further. The central position of the weakening line in the length direction is provided so as to avoid a region from the start end portion of the male screw portion to a position of 10 ° toward the front along the circumferential direction.

The starting end of the male thread is a part where the shape of the mouth changes along the circumferential direction, and if a linear weakening line is placed near it, it leaks from the weakening line when it is impacted by a drop, for example. May occur. Further, in the first round of the male threaded portion, the gap between the peripheral wall of the cap and the mouth of the bottle can is large at the portion up to a position 80 ° advanced from the start end of the threaded portion, so that the cap is easily deformed at the time of a drop impact.
Therefore, the center position in the length direction of the weakening line should not be arranged in the angle range of 90 ° along the male thread portion from the position of 10 ° in front of the start end portion of the male thread portion, specifically, the position of 10 ° in front of the start end portion. , The occurrence of leakage is suppressed.

The method for sealing a bottle can with a cap of the present invention is a method in which a cap is attached to a male screw portion formed at the mouth of the bottle can to seal the bottle, and a vent hole for releasing the internal pressure at the time of opening and a predetermined internal pressure. In the cap forming step of forming a cap having a linear weakening line along the circumferential direction of opening, and the center position of the weakening line in the length direction from the opening end of the mouth portion to the thread of the male thread portion. A sealing step of sealing the cap to the male threaded portion of the bottle can mouth portion is provided so as to avoid a region where the distance to the ridgeline is less than 4.90 mm .
In the method for sealing a bottle can with a cap of the present invention , preferably, the region where the distance is less than 4.90 mm is from the start end portion of the male threaded portion to a position advanced by 80 ° in the circumferential direction along the male threaded portion. Further, in the sealing step, the center position of the weakening line in the length direction is arranged so as to avoid a region from the start end portion of the male screw portion to a position of 10 ° toward the front along the circumferential direction. The cap is sealed in the male screw portion.

As one embodiment of these sealing methods, in the sealing step, the cap is positioned at the center position of the weakening line of the cap so as to avoid the region, and the cap is placed on the mouth of the bottle can. After covering the cap, the cap-side threaded portion of the cap is formed and sealed while following the male threaded portion.

As another embodiment, in the cap forming step, a cap-side threaded portion that can be screwed into the male-threaded portion of the bottle can is formed in the cap, and the cap-side threaded portion is screwed into the male-threaded portion. The weakening line is formed so that the center position of the weakening line in the length direction is arranged so as to avoid the region, and in the sealing step, the cap is rotated to the mouth portion of the bottle can. The cap-side screw portion may be screwed into the male screw portion while allowing the screw to be screwed.

According to the present invention, since the position of the weakening line for explosion prevention is arranged so as to avoid a specific region, it is possible to prevent the phenomenon that the weakened portion is inadvertently opened.

It is a partial cross-sectional view which shows the bottle can with a cap of embodiment of this invention, (a) is the state before winding a cap into a bottle can, (b) is after winding a cap into a bottle can. Shows the state of a bottle can with a cap. It is a front view in the state before winding a cap into a bottle can. It is a bottom view of a cap. It is a front view of a bottle can. It is a cross-sectional view of the mouth of a bottle can. It is sectional drawing of the main part for demonstrating the sealing method by a capping device. It is a vertical cross-sectional view of two places different in the circumferential direction of the mouth of a bottle can.

Hereinafter, embodiments of a bottle can with a cap according to the present invention will be described with reference to the drawings.
As shown in FIG. 1 (b), the cap 10 used for the capped bottle can 100 of the present embodiment is attached to the mouth 21 of an aluminum or aluminum alloy (metal) bottle can 20 having a diameter of 38 mm, for example. It becomes a pilfer proof cap (hereinafter, also referred to as PP cap) that is closely attached.
The cap 10 is formed by molding a plate material made of aluminum or an aluminum alloy into a cup shape, and includes a top surface portion 41 and a cylindrical portion 42 substantially hung from the peripheral edge of the top surface portion 41 as shown in FIG. It has a cap main body 40 and a liner 50 provided on the inner surface of the top surface portion 41 of the cap main body 40.

As shown in FIG. 4, the mouth portion 21 of the bottle can 20 to which the cap 10 is mounted has a bulging portion 22 protruding outward in the radial direction at the lower end portion thereof, and a male screw portion 23 and a male screw above the bulging portion 22. A curl portion 24 having an open end rounded is formed above the portion 23. A tapered surface 25 is formed between the lower end of the curl portion 24 and the upper edge of the thread for the first round of the male thread portion 23 to gradually increase the diameter from the lower end of the curl portion 24 toward the upper edge of the male thread portion 23. Has been done.
In the cap 10 covered on the mouth portion 21 of the bottle can 20, the cap side screw portion 13 screwed to the male screw portion 23 is formed on the cylindrical portion 42, and the lower end portion of the cylindrical portion 42 is on the lower surface of the bulging portion 22. Locked, the liner 50 is pressed against the curl portion 24, and the bottle can 20 is sealed to form a capped bottle can 100.

As shown in FIG. 2, the cylindrical portion 42 of the cap body 40 has a cylinder upper portion 43 and a cylinder lower portion 44 which are vertically divided via a slit 17 formed intermittently in the circumferential direction at the lower end portion thereof. The upper cylinder 43 and the lower cylinder 44 are connected by a plurality of bridges 17a formed between the slits 17 adjacent to each other in the circumferential direction.

Further, in the vicinity of the top surface portion 41 of the cylindrical portion 42, as shown in FIG. 2, a plurality of knurled recesses 31 which are concave inward in the radial direction and slit-shaped openings are formed in the circumferential direction to form an internal pressure at the time of opening. A plurality of vent holes (vent holes of the present invention) 32 for opening are provided side by side at intervals in the circumferential direction. The vent hole 32 is provided with an upper protrusion 33 and a lower protrusion 34 formed by bending the end of the upper opening and the end of the lower opening inward in the radial direction of the cylindrical portion 42. Further, along with these knurl recesses 31 and vent holes 32, when the cap body 40 is attached to the mouth portion 21 of the bottle can 20 and a predetermined internal pressure (for example, 700 kPa) is reached, the cap body 40 forms a linear shape along the circumferential direction of opening. One formed internal pressure opening slit (weakening line of the present invention) 35 is provided.

As shown in FIG. 2, the internal pressure opening slit 35 is formed in a linear slit longer than the vent hole 32 extending linearly in the circumferential direction of the cylindrical portion 42, and is the same as the vent hole 32. It is located at a height or below the vent hole 32. Then, when the internal pressure of the bottle can 20 rises excessively due to fermentation of the contents or the like, the internal pressure opening slit 35 opens at a predetermined internal pressure opening value (for example, 700 kPa) to release the internal gas. It serves as a so-called explosion-proof function.

The longer the length of the internal pressure opening slit 35, the lower the internal pressure opening value can be. For example, if the cap body 40 (cylindrical portion 42) is formed to have a length of 8% or more of the peripheral length, the cap 10 can be effectively suppressed from popping out. On the other hand, if the length of the internal pressure opening slit 35 is made too long, the rigidity is lowered and the internal pressure opening value becomes too low, and deformation during capping is likely to occur. In addition, if the internal pressure release value is too low, the internal pressure may be released at an unintended timing (for example, during sterilization of the contents), so it is necessary to stabilize the internal pressure release value and control it to an appropriate value. .. The preferable length of the internal pressure opening slit is 8% or more and 15% or less of the peripheral length of the cap body. The peripheral length of the vent hole 32 is set to be sufficiently shorter than the length of the internal pressure opening slit 35, and the lower protrusion 34 is pushed inward in the radial direction to widen the gap between the slits and individually. While forming a relatively large opening area, it has the effect of increasing the rigidity of that portion.

The knurled recess 31, the upper protrusion 33, and the lower protrusion 34 have a concave shape on the outer peripheral surface of the cylindrical portion 42, and by arranging them at intervals, an uneven surface is formed on the outer peripheral surface of the cylindrical portion 42. Is formed, and the frictional resistance between the finger holding the cap 10 at the time of opening can be increased. This makes it possible to grip the cap 10 without slipping the hand, and it is possible to easily open the cap 10.

Further, the vent hole 32 is formed by being sheared in the circumferential direction of the cylindrical portion 42, and when the cap 10 attached to the bottle can 20 is rotated upward while breaking the bridge 17a, the inside of the bottle can 20 is formed. Gas is released to the outside.
Further, the tip of the upper protrusion 33 of the vent hole 32 is located inward in the radial direction from the outer peripheral edge of the liner 50 when inserted, and is at the same position in the radial direction as the tip of the lower protrusion 34. It is located radially outside the tip. Further, the tip portion of the upper protrusion 33 is further bent downward so that the tip surface is directed downward.

The liner 50 inserted into the cap body 40 abuts on the curl portion 24 of the bottle can 20 when the cap 10 is closed, and is formed so as to be able to seal the inside of the bottle can 20 as shown in FIG. 1 (a). The contact surface with the curl portion 24 is provided flat in the state before capping. In this way, by forming the portion (contact surface) where the liner 50 contacts the curl portion 24 flat in the state before capping, the liner 50 is formed on the curl portion 24 after the cap 10 is attached to the curl portion 24. Although the cap 10 is pressed against the 24 and slightly deformed, the liner 50 is provided substantially flat when the cap 10 rotates in the circumferential direction and a slight gap is provided between the liner 50 and the curl portion 24. Since the opening flow path of the internal pressure inside the bottle can 20 is directly secured toward the vent hole 32 between the surface of the bottle can 20 and the curl portion 24, the internal pressure can be smoothly released.

Specifically, as shown in FIG. 1, such a liner 50 includes a sealing layer 51 formed of an elastomer resin or the like and having a sealing function, and polypropylene or the like having a hardness higher than that of the sealing layer 51. It is possible to use a disk-shaped top surface portion 41 formed of the above in which the inner surface and the sliding sliding layer 52 are laminated. In this case, the sealing layer 51 is provided to have a smaller outer diameter than the sliding layer 52, and the tip of the upper protrusion 33 is located radially inward with respect to the outer peripheral edge of the sliding layer 52 of the liner 50, and the lower portion thereof. The tip of the protrusion 34 is located radially outward of the outer peripheral edge of the sealing layer 51. Then, the surface (contact surface) of the sealing layer 51 in which the liner 50 contacts the mouth portion 21 is provided flat.

Next, as shown in FIG. 1 (b), a capped bottle can 100 in which the mouth portion 21 of the bottle can 20 is covered with a cap 10 and sealed tightly will be described.
In the cap 10 covered on the mouth portion 21 of the bottle can 20, the peripheral edge portion of the top surface portion 41 is drawn, and the cap side threaded portion 13 along the outer diameter of the male threaded portion 23 is formed on the cylinder upper portion 43 and swells. By forming the pilfer proof portion 14 along the lower portion of the protruding portion 22 in the lower portion 44 of the cylinder, it is adhered to the mouth portion 21 of the bottle can 20. Further, the liner 50 of the cap 10 is in close contact with the curl portion 24, so that the opening 20a of the bottle can 20 is sealed.

In the bottle can 100 with a cap configured in this way, the internal pressure release slit (weakening line) is located at a position of 10 ° toward the front from the start end portion 23a of the male screw portion 23 of the bottle can 20 along the circumferential direction, and the start end portion thereof. It is provided so as to avoid the region C partitioned between the position 23a and the position advanced by 80 ° in the circumferential direction along the male screw portion 23.

FIG. 7 shows a vertical cross-sectional shape of a portion (a portion shown by A in FIG. 4) including the start end portion 23a of the male screw portion 23 in (a), and FIG. 7 (b) is a portion in front of the portion (B in FIG. 4). It is a vertical cross-sectional shape of the part (indicated by). As is clear from FIG. 7, the distance in the can axis direction from the upper end (open end) of the curl portion 24 to the ridgeline of the thread of the male thread portion 23 changes as the bottle can 20 is directed toward the circumferential direction. The start end portion 23a of the male threaded portion 23 is formed as short as L1, and the portion in front of the male threaded portion 23, that is, near the end portion of the first round, is formed as long as L2. Further, at the portion before the start end portion 23a of the male screw portion 23, that is, at the end portion of the first round of the male screw portion 23, the tapered surface 25 between the upper edge of the male screw portion 23 and the lower end of the curl portion 24 (FIG. 7B). ) Is a steeper inclined surface than the tapered surface 25 (FIG. 7 (a)) between the upper edge of the start end portion 23a of the male screw portion 23 and the lower end of the curl portion 24, and is formed on the tapered surface 25 at the end portion of the first round. On the other hand, the starting end portion 23a of the male threaded portion 23 is in a state of greatly protruding outward in the radial direction.

In this way, in the vicinity of the start end portion 23a of the male screw portion 23 of the bottle can 20, the start end portion 23a of the male screw portion 23 is formed so as to rise from the tapered surface 25, and the shape of the mouth portion 21 of the bottle can 20 is in the circumferential direction. It changes greatly toward.
Further, at the start end portion 23a of the male screw portion 23, the distance L1 from the upper end of the curl portion 24 to the ridgeline of the screw thread is small, and the screw thread protrudes greatly outward in the radial direction. As shown in FIG. 7A, a large space portion X is formed between the outer surface of the mouth portion 21 of the bottle can 20 and the inner surface of the peripheral wall of the cap 10.
The internal pressure opening slit 35 is provided in a portion where the shape of the mouth portion 21 of the bottle can 20 changes significantly, or in a portion where the distance L1 from the upper end of the curl portion 24 to the ridgeline of the screw thread is small and a large space portion X is formed. If arranged, the internal pressure opening slit 35 may be inadvertently opened at the time of a drop impact or the like. On the other hand, in the portion before the start end portion 23a of the male screw portion 23, the tapered surface 25 is a steeply inclined surface as described above, and the distance L2 from the upper end of the curl portion 24 to the ridgeline of the thread of the male screw portion 23 is long. As shown in FIG. 7B, the peripheral wall of the attached cap 10 is also arranged close to the outer surface of the mouth portion 21. Therefore, the deformation of the cap 10 at the time of a drop impact is also reduced.
Since the above-mentioned state in which the large space portion X is formed continues for a while from the vicinity of the start end portion 23a of the male screw portion 23 along the male screw portion 23, the range is within 10 ° in front of the start end portion 23a of the male screw portion 23. The internal pressure opening slit 35 is not arranged in the range from the start end portion 23a to the position advanced by 80 ° in the circumferential direction.

In this case, since the internal pressure opening slit 35 has a length along the circumferential direction of the cap 10, at least the intermediate position in the length direction of the internal pressure opening slit 35 is along the circumferential direction from the start end portion 23a of the male screw portion 23. It is provided so as to avoid the region C defined between the position 10 ° in front of the surface and the position advanced by 80 ° in the circumferential direction from the starting end portion 23a along the male screw portion 23.
In addition, in the case of a bottle can having a diameter of 38 mm, the position advanced by 80 ° in the circumferential direction from the starting end portion 23a of the male threaded portion 23 is the thread of the male threaded portion 23 from the open end (upper end of the curl portion 24) of the mouth portion 21. Since the distance to the ridgeline is about 4.85 mm as described later, the range of 10 ° in front of the start end portion 23a of the male threaded portion 23 and the distance from the open end of the mouth portion 21 to the ridgeline of the thread of the male threaded portion 23. It is preferable that the center position of the internal pressure opening slit 35 in the length direction is arranged so as to avoid the region where the height is less than 4.90 mm.

In the bottle can 100 with a cap, in order to arrange the internal pressure opening slit 35 so as to avoid the region C, a cap 10 having a cylindrical portion 42 is formed as shown in FIGS. 1 (a) and 2 (a). Put the cap on the mouth 21 of the bottle can 10 in a state where the center position of the internal pressure opening slit 35 of the cap 10 is positioned with respect to the bottle can 10 so as to avoid the region C. After that, the capping device shown in FIG. 6 is used for sealing (sealing step).

In this sealing step, the top surface 41 of the cap 10 is pressed in the can axis direction of the screwed bottle can 10 by the pad 81, and at the same time, the peripheral edge of the top surface 41 is drawn by the annular block 82, and capping is performed in this state. The cylindrical portion 42 is pressed against the male threaded portion 32 of the base portion 23 by the roll 83 to form the cap side threaded portion 13 on the cylindrical portion 42 along the male threaded portion 32, and the cylindrical portion 42 is formed on the bulging portion 33 by the skirt roller 84. Wrap the lower end of the.

To position the cap 10 and the bottle can 20, the bottle can 20 and the cap 10 are installed at separate stations before the cap 10 is placed on the bottle can 20, and the bottle can 20 is rotated about the axis of each. The start end portion 23a of the male screw portion 23 is detected by the sensor, and the internal pressure opening slit 35 is detected by the sensor for the cap 10. When the start end portion 23a of the male screw portion 23 and the internal pressure opening slit 35 are detected, the rotation of the bottle can 20 and the cap 10 is stopped in a posture in which they face a predetermined direction, and the center position of the internal pressure opening slit 34 of the cap 10 is the bottle. Capping may be performed by covering the can 20 so as to avoid the region C of the male screw portion 23.

Further, as another sealing method, the cap side screw portion 13 may be formed in advance on the cap 10 in the cap forming step. At that time, the internal pressure opening slit 35 is formed so that the center position of the internal pressure opening slit 35 in the length direction is arranged avoiding the region B when the cap side screw portion 13 is screwed into the male screw portion 23.
Then, in the sealing step, a capping device having a mechanism for rotating the cap 10 around the axis and a skirt roller similar to the above-mentioned skirt roller 84 is used, and the cap 10 is put on the mouth portion 21 of the bottle can 20 while rotating. , The cap side screw portion 13 may be screwed into the male screw portion 23 of the bottle can 20, and then the lower end portion may be wound around the bulging portion 33 with a skirt roller.
In this sealing method, positioning in the circumferential direction is not required when the cap 10 is put on the mouth portion 21 of the bottle can 20.

By the way, in the manufacturing process, the male screw portion 23 of the bottle can 20 sandwiches the can body between the core inserted inside the can and the outer element arranged outside the can body, and rotates these cores and outer elements. It is formed by revolving around the axis of the can body while allowing it to revolve. The start end portion 23a of the male screw portion 23 is generally formed at a position where the core and the outer core start to sandwich the can body.
However, depending on the bottle can, the core and the outer element gently pinch the can body, and as a result, the start end of the male threaded portion cannot be clearly identified, and the incomplete threaded portion is formed long in the circumferential direction. There are also bottle cans that have been made.
Even in the case of a bottle can in which the start end of the male thread cannot be clearly identified, the internal pressure release slit should not be placed within the range until the distance from the upper end of the curl to the ridge of the thread of the male thread reaches a predetermined dimension. Need to be.
In the case of such a bottle can, as described above, the length of the internal pressure opening slit 35 avoids the region where the distance from the open end of the mouth portion 21 to the ridgeline of the thread of the male thread portion 23 is less than 4.90 mm. It is preferable that the center position in the direction is arranged. In this bottle can, since the starting end portion does not clearly appear on the male screw portion 23, it is not necessary to consider the portion in front of the starting end portion 23a as in the above-described embodiment.

In the embodiment, the weakening line is an internal pressure opening slit composed of linear slits, but if the weakening line is linear along the circumferential direction of opening when a predetermined internal pressure is reached, a plurality of intermittently formed slits. It may be due to a single long slit, or a groove-shaped notch may be formed in the peripheral wall of the cap to make it thinner than the thickness of the other portion, and the score may be broken when the internal pressure is released. ..

Next, a bottle can with a cap was actually manufactured and a drop impact test was conducted.
As each bottle can, an aluminum bottle can having an internal capacity of 390 ml and having a mouth portion having a diameter of 38 mm was used. Further, in each cap, an internal pressure opening slit having a length of 10 mm was formed in the aluminum cap body together with a knurl recess and a vent hole.
Then, the bottle can was filled with 390 ml of water and the cap was attached. At this time, various bottle cans with caps having different circumferential distances between the internal pressure opening slit of the cap and the starting end of the male screw portion of the bottle can were manufactured.
In the drop impact test, the product is dropped in an inverted (vertical) posture so that the outer peripheral portion of the top surface on which the internal pressure opening slit is formed collides with the iron plate inclined by 10 ° from a height of 30 cm, and then placed upright. I left it for a day. Then, the internal pressure before and after the drop was measured, and the number of the internal pressure decreased (leakage) was confirmed.
The results are shown in Table 1. The angle column is an angle along the circumferential direction to the center position in the length direction (circumferential direction) of the internal pressure opening slit of the cap with the position of the starting end of the male screw portion as a reference (0 °). The angle range is shown in the lower row. The upper row is less than the stated value, and the lower row is more than the stated value.

As shown in Table 1, leakage was observed in the range where the angle along the circumferential direction of the center position in the length direction of the internal pressure release slit of the cap from the start end of the male screw portion was 355 ° or more and less than 80 °. No leakage was observed in the range of 80 ° or more and less than 355 °.
From this result, the center position of the internal pressure release slit in the length direction is 10 ° toward you from the start end of the male screw portion along the circumferential direction, and the position advanced by 80 ° in the circumferential direction from the start end along the male screw portion. It can be seen that the occurrence of leakage can be prevented by providing the area avoiding the area partitioned between the and.
The distance from the open end (upper end of the curl part) of the mouth of the bottle can to the ridgeline of the thread of the male thread is the shortest at the start of the male thread, about 4.42 mm, from the start of the male thread. It was about 4.85 mm at a position of 70 ° or more and less than 80 °. Then, the distance gradually increases as the distance advances to 80 ° or more. Therefore, in the case of a bottle can in which the starting end of the male thread cannot be clearly identified, the distance from the open end (upper end of the curl) of the mouth of the bottle can to the ridgeline of the thread of the male thread is less than 4.90 mm. It is preferable that the center position in the length direction of the internal pressure release slit is arranged so as to avoid the region where the internal pressure is released.

10 Cap 13 Cap side threaded part 14 Pilfer proof part 17 Slit 17a Bridge 20 Bottle can 21 Mouth part 22 Swelling part 23 Male threaded part 24 Curled part 31 Nar recess 32 Vent hole 35 Internal pressure opening slit (weakening line)
40 Cap body 41 Top surface 42 Cylindrical part 43 Cylinder upper part 44 Cylinder lower part 50 Liner 100 Bottle can with cap (bottle can with cap)

Claims (6)

A bottle can with a cap that is tightly closed by attaching a cap to the male threaded part formed at the mouth of the bottle can. A linear weakening line is provided along the direction, and the distance from the opening end of the mouth portion to the ridgeline of the thread of the male thread portion is less than 4.90 mm at the center position of the weakening line in the length direction. A bottle can with a cap, which is characterized by being provided avoiding the area where it becomes. The region where the distance is less than 4.90 mm is from the start end portion of the male threaded portion to a position advanced by 80 ° in the circumferential direction along the male threaded portion.
Further, claim 1 is characterized in that the central position of the weakening line in the length direction is provided so as to avoid a region from the start end portion of the male screw portion to a position of 10 ° toward the front along the circumferential direction. The listed bottle can with cap. It is a method of attaching a cap to the male threaded part formed at the mouth of the bottle can and sealing it tightly. A vent hole that releases the internal pressure when the bottle is opened and a linear weakening along the circumferential direction that opens when the internal pressure reaches a predetermined level. A cap forming step of forming a cap having a line and a region where the center position of the weakened line in the length direction is less than 4.90 mm from the opening end of the mouth portion to the ridgeline of the thread of the male thread portion. A method for sealing a bottle can with a cap, which comprises a sealing step of sealing the cap to a male screw portion of the bottle can mouth portion so as to avoid the above. The region where the distance is less than 4.90 mm is from the start end portion of the male threaded portion to a position advanced by 80 ° in the circumferential direction along the male threaded portion.
Further, in the sealing step, the male screw is arranged so that the center position in the length direction of the weakening line is arranged so as to avoid a region from the start end portion of the male screw portion to a position of 10 ° toward the front along the circumferential direction. The method for sealing a bottle can with a cap according to claim 3, wherein the cap is sealed in a portion. In the sealing step, the center position of the weakening line of the cap is positioned so as to avoid the region, the cap is put on the mouth portion of the bottle can, and then the cap is imitated by the male screw portion. The method for sealing a bottle can with a cap according to claim 3 or 4, wherein a screw portion on the cap side of the cap is formed and sealed. In the cap forming step, a cap-side threaded portion that can be screwed into the male-threaded portion of the bottle can is formed in the cap, and the length of the weakening line is formed when the cap-side threaded portion is screwed into the male-threaded portion. The weakening line is formed so that the center position in the radial direction is arranged so as to avoid the region. The method for sealing a bottle can with a cap according to claim 3 or 4, wherein the side screw portion is screwed.

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