JP4716490B2 - Sealed liner structure for threaded can caps - Google Patents

Description

  The present invention relates to the structure of a sealing liner attached to the inner surface of the top plate portion of the cap, and in particular, to the mouth and neck of the can in which the curl portion, the inclined wall, and the screw portion are formed sequentially from top to bottom. With a screw that forms the stepped part by drawing the connection part between the top plate part of the shell and the skirt part when installing it while forming the screw in the skirt part of the shell according to the screw of the neck and neck The present invention relates to a sealing liner structure in a can cap.

  A cap made of a thin metal plate shell with a skirt portion suspended from the periphery of the top plate portion via a connecting portion, and an elastically deformable resin sealing liner attached to the inner surface of the top plate portion of the shell. The top and bottom of the cap is pressed from above by roll-on molding with a capping device (capper), covering the mouth and neck of the can in which the curled portion, the inclined wall and the screw portion are formed sequentially from the top to the bottom. While attaching the cap to the mouth and neck while forming the screw on the skirt of the shell to match the screw on the mouth and neck, the connecting part between the top plate of the cap shell and the skirt is drawn. By forming the stepped portion, pressing the resin liner from the outside to the curled portion of the mouth-and-neck portion strengthens the adhesion between the curled portion and the liner and makes the seal of the can more reliable. Is conventional It has been carried out, et al.

  Regarding the sealing liner structure of such a threaded can cap, Patent Document 1 below can sufficiently secure the sealing performance between the curled portion and the liner without deforming the curled portion when the cap is attached. In addition, a structure for smoothly opening and closing the cap at the time of opening and use after opening is disclosed, and Patent Document 2 below discloses the upper end of the skirt portion of the cap shell. In a cap in which a plurality of vent hole portions are formed in the vicinity in the circumferential direction, when the shower water is allowed to enter the cap from the vent hole portion and the screw portion of the container is washed, water is introduced into the curl portion. A structure for preventing intrusion is disclosed.

That is, in Patent Document 1 below, in order to further improve the sealing performance between the curl portion and the liner, the outer annular rib of the liner is placed more than the curl center of the curl portion with the cap attached to the mouth and neck portion. A structure is disclosed in which contact is made down (lower than the maximum outer diameter portion of the curl portion), and Patent Document 2 prevents water that has entered from the vent hole portion from entering the curl portion. In order to achieve this, a structure is disclosed in which the outer peripheral end of the sealing material (liner) is brought into contact with the outer peripheral surface of the container below the lower end of the curled part of the container (the portion of the inclined wall formed below the curled part). Yes.
JP 2001-139053 A JP 2004-284607 A

  By the way, it is a screwed can that strengthens the adhesion between the curl portion of the mouth and neck and the liner of the cap by forming the connection portion between the top plate portion and the skirt portion of the cap shell at the stepped portion. However, when producing canned products using this, the contents should be hot-filled and sealed, or the contents should be filled and sealed before retort sterilization (for example, 130 ° C. for 30 minutes). In such a case, the sealing performance of the can may be deteriorated because the top plate portion of the cap is displaced up and down due to a change in the internal pressure of the cap and the close contact state between the curl portion and the liner is changed. Also, when the canned product is accidentally dropped with the cap side down during storage and handling of the manufactured canned product, the cap is deformed and the contact area between the liner and the curled portion is reduced. As a result, the sealing performance of the can may be reduced.

  In addition, the above Patent Document 1 discloses a structure in which the outer annular rib of the liner is brought into close contact with the curl center below the curl center (below the maximum outer diameter part of the curl part). Document 2 discloses a structure in which the outer peripheral end portion of the sealing material (liner) is brought into contact with the outer peripheral surface of the container below the lower end of the curled portion of the container (the portion of the inclined wall formed below the curled portion). However, as a result of studies by the present inventor, it has been found that even if such a structure is adopted, there are cases where it is insufficient to reliably solve the above problems.

  An object of the present invention is to solve the above-described problems. Specifically, in a sealing liner structure of a cap for a screwed can, the top plate portion of the cap is displaced up and down due to a change in can internal pressure. Even if the cap is deformed by dropping, it is an object to ensure sufficient sealing performance of the can by the curl portion of the mouth-neck portion and the liner of the cap.

In order to solve the above problems, the present invention is attached to a shell made of a thin metal plate in which a skirt portion is suspended from a peripheral edge of a top plate portion via a connection portion, and an inner surface of the top plate portion of the shell. A shell made of an elastically deformable resin liner is shelled in accordance with the screw of the mouth and neck against the mouth and neck of the can where the curled part, the inclined wall and the screw part are formed sequentially from top to bottom. In a cap for a threaded can that is formed in a stepped portion by drawing the connecting portion between the top plate portion of the shell and the skirt portion when the screw is attached to the skirt portion of the shell, the cap is connected to the mouth and neck. In a state where the resin liner is mounted, the resin liner is in close contact with the curled portion having a curved surface that bulges outward, and is in close contact with the lower inclined wall of the curled portion, and until below the shoulder of the stepped portion between the top plate portion and a skirt portion With close contact with the E le, near the upper end of the skirt portion of the shell of the cap, the vent hole portion which opens above the cut portion recessed inward are formed at a plurality of locations along the circumferential direction, the cap The resin liner is configured to come into contact with the upper end portion recessed inward of each vent hole portion in a state in which is attached to the mouth and neck portion .

According to the sealing liner structure of the threaded can cap of the present invention as described above, the liner extends to a position lower than the shoulder portion of the step portion between the top plate portion and the skirt portion with the cap mounted on the mouth and neck portion. Is in close contact with the shell, so that the liner can be attached at the close contact portion of the liner that is in close contact with the curl portion below the maximum outer diameter portion of the curl portion or at the close contact portion of the liner that is in close contact with the inclined wall below the curl portion. As a result, even if the top plate of the cap is displaced up and down due to changes in the internal pressure of the can, or even if the cap is deformed due to dropping or the like, the curled portion of the mouth and neck and the cap The can can be sufficiently sealed with the liner.

Further, in the vicinity of the upper end of the skirt portion of the shell of the cap, the vent hole portion which opens above the cut portion recessed inwardly with respect to what is formed at a plurality of locations along the circumferential direction, the cap When the top plate of the cap swells outward due to the internal pressure of the can, the resin liner is brought into contact with the upper end of the vent hole that is recessed inward while attached to the mouth and neck. In addition, the liner can be more securely fixed and held by the vent hole part, and gas leakage from the vent hole part can be prevented by the liner, so that deterioration of the sealing performance can be surely prevented and the cap is slightly opened. It is possible to prevent loosening of the screwing with the mouth and neck by rotating in the direction by contact friction between the liner and the vent hole, and reliably preventing deterioration of the sealing performance due to loosening of the screwing of the cap. To do It can be.

In addition, in the pilfer proof cap in which the lower end portion of the skirt portion of the cap shell is a pilfer proof ring, the cap attached to the mouth and neck in an unopened state is intentionally slightly opened in the direction of opening. By turning, there is a risk of mischief such as leaking gas in the can without breaking the weakened part of the pill fur proof ring. It is difficult to intentionally rotate the cap slightly by making it abut against the vent hole. (If the force is weak, the cap will not rotate at all. If force is applied, the weakened part of the pilfer proof ring will break. As a result, such mischief can be prevented and the pilfer proof effect can be enhanced.

Regarding the sealing liner structure of the cap for threaded cans, even if the top plate of the cap is displaced up and down due to changes in the internal pressure of the cap, or the cap deforms due to falling, the curled part of the mouth and neck and the cap As shown in the following embodiment as the best mode, the skirt portion is connected from the peripheral edge of the top plate portion through the connecting portion, in order to ensure sufficient sealing performance of the can by the liner of the present invention. A cap made of a thin metal plate shell and an elastically deformable resin liner attached to the inner surface of the top plate portion of the shell, and a curled portion, an inclined wall, and a screw portion are sequentially arranged from top to bottom. When attaching the formed can to the mouth and neck of the shell while forming the screw on the skirt of the shell in accordance with the screw of the mouth and neck, the connection between the top plate and the skirt of the shell is squeezed. Processed to form a step In such a can cap with a screw, the resin liner adheres below the maximum outer diameter portion of the curled portion having a curved surface that bulges outward with the cap mounted on the mouth and neck. In close contact with the inclined wall below the curled portion, and in close contact with the shell below the shoulder portion of the step between the top plate portion and the skirt portion, and near the upper end of the skirt portion of the shell of the cap, Bent hole parts that are recessed inward and open at the upper notch are formed at multiple locations along the circumferential direction, and with the cap attached to the mouth and neck, resin liners are attached to each vent. This is realized by a configuration in which the upper end of the hole is recessed inward .

Examples of the sealing liner structure of the cap for a threaded can according to the present invention will be described below. In this embodiment , as shown in FIGS. 1 and 4, the cap 1 hangs a substantially cylindrical skirt portion 13 from a peripheral edge of a substantially disc-shaped top plate portion 11 via a curved connection portion 12. A pilfer proof cap comprising a thin metal sheet shell (cap body portion) 10 and a resin sealing liner 20 attached to the inner surface of the top plate portion 11 of the shell 10. The screwed can 2 to be mounted is a bottle-shaped can made of a thin metal plate in which the mouth-and-neck portion 3 is integrally erected upward from the shoulder portion 4.

  In the unused cap 1 before being attached to the mouth and neck portion 3 of the can 2, the central portion of the skirt portion 13 of the shell 10 is a cylindrical portion 15 in which a screw is formed when the cap is attached. When the cap 1 is attached to the mouth / neck portion 3, a screw is formed so as to match the screw 33 of the mouth / neck portion 3 by pressing a roll against the cylindrical portion 15 from the side. Further, a weakened portion 16 formed of a plurality of bridges and slits is formed below the cylindrical portion 15 of the skirt portion 13, and a pilfer proof ring 17 is formed below the weakened portion 16. When the cap 1 attached to the mouth / neck portion 3 is first opened and opened, if the cap 1 is rotated in the opening direction, the bridge of the weakened portion 16 is broken, and the pilfer proof ring 17 becomes the skirt of the cap 1. It is cut off from the part 13 and remains in the mouth and neck part 3 of the can 2.

  In addition, about the specific structure of the pilfer proof (tamper evidence) function for preventing mischief such as unauthorized use by clearly showing the opened state, the weakened portion 16 with a plurality of bridges and slits as described above. For example, the weakened portion 16 may have a score (marked line) with a thin plate thickness, or the ring portion when the plug is opened. Can be implemented with an appropriate structure, such as a structure in which the structure is broken in the longitudinal direction at a plurality of locations at intervals in the circumferential direction.

  In the mouth and neck 3 of the can 2 to which the cap 1 is attached, an outer curled portion 31 formed in a ring shape along the upper end opening edge in order from the top to the bottom, and a lower portion from the curled portion 31 and An inclined wall 32 extending outward, a screw part 33 extending downward from the inclined wall 32, a bead part 34 continuing below the screw part 33, and a small-diameter cylindrical part 35 provided below the bead part 34 are integrated. Is formed.

  The bead portion 34 and the small-diameter cylindrical portion 35 below the cap portion 1 are covered with the cap 1 and the cylindrical portion 15 of the skirt portion 13 of the cap 1 is screw-formed by a capping device (capper). However, when attaching to the mouth-and-neck portion 3, the capper roller enters the small-diameter cylindrical portion 35, deforms the lower end portion of the pill fur proof ring 17 of the cap 1, and this portion is connected to the bead portion 34 and the small-diameter cylindrical portion 35. The pilfer proof ring 17 is locked and fixed to the mouth-and-neck portion 3 by being squeezed so as to be pressed against the stepped portion therebetween.

In this embodiment using the cap 1 and the mouth and neck portion 3 of the can 2 as described above, when the seal by the liner 20 is released on the upper portion of the skirt portion 13 of the shell 10 of the cap 1 as shown in FIG. Further, vent holes 19 for effectively degassing the can are formed at a plurality of locations along the circumferential direction so as to prevent slipping when the cap 1 is rotated. In the state where the cap 1 is attached to the mouth-and-neck portion 3, as shown in FIGS. 3 and 4, the outer annular rib 24 of the liner 20 has the top plate portion 11 and the skirt portion with respect to the shell 10 of the cap 1. The maximum outer diameter portion of the curled portion 31 (which is in close contact with the shoulder portion 18b of the step portion 18 between 13 and below and has a curved surface that bulges outward from the mouth neck portion 3 of the can 2). The outer peripheral surface of the curled portion 21 at the height of the curl center O) is in close contact with the inclined wall 32 below the curled portion 31, and is recessed inward and opened at the upper cut portion. The vent hole portion 19 is in contact with an upper end portion 19a that is recessed inwardly.

  The sealing resin liner 20 attached to the inner surface (back surface) of the top plate portion 11 of the shell 10 of the cap 1 is made of a synthetic resin material injected in a molten state on the inner surface of the top plate portion 11 of the cap 1. The liner 20 made of a well-known synthetic resin material such as a polyethylene resin or a polypropylene resin, which can be elastically deformed, is integrally formed by a well-known embossing molding method. A plate-like thin flat portion 21 is formed, and two annular ribs 22 and 24 arranged concentrically with an annular flat surface 23 in between are formed on the periphery thereof. The liner 20 is not limited to a disk-like one as a whole having a disk-like flat part 21 at the center, but includes two annular ribs 22 and 24 and an annular flat surface 23 in the peripheral part. The whole may be annular.

  In such a state that the unused cap 1 is simply put on the mouth and neck portion 3 of the can 2, as shown in FIG. 2, it can be pressed against the curled portion 31 at the upper end of the mouth and neck portion 3 from above. The two annular ribs 22, 24 of the liner 20 that is not elastically deformed are crested in a longitudinal section with the outer wall 22 a of the inner annular rib 22 and the inner wall 24 a of the outer annular rib 24 as the top of the annular flat surface 23. In order to form a mold, each of them is inclined symmetrically. When viewed from the curl center O of the curled portion 31, the outer annular rib 24 is located radially outward and the inner annular rib 22 is radially inward. The curled portion 31 is surrounded by the annular ribs 22 and 24 and the annular flat surface 23 from both sides.

  When the cap 1 is attached to the mouth / neck portion 3 from the state in which the cap 1 is simply put on the mouth / neck portion 3 in such a manner, a known capping device (capper) is used and 1274 to a maximum from above. Applying a vertical load of about 1372 N to the cap 1 and pressing the cap 1 from above, the curved connection portion 12 from the peripheral portion of the top plate portion 11 to the upper portion of the skirt portion 13 (knurl portion 14) Drawing is performed so as to squeeze inward, and a screw is formed on the cylindrical portion 15 of the skirt portion 13 by a roll in accordance with the screw of the screw portion 33 of the mouth-and-neck portion 3. Further, the pilfer proof ring 17 The pill fur proof ring 17 is locked and fixed to the mouth-and-neck portion 3 by narrowing the lower end portion of the neck portion 35 into the small-diameter cylindrical portion 35 of the mouth-and-neck portion 3 with a roll.

By the way, in the state where the cap 1 is mounted on the mouth neck portion 3 of the can 2 as described above, the liner 20 attached to the inner surface of the top plate portion 11 of the shell 10 as shown in FIGS. The inner annular rib 22 and the annular flat surface 23 are in close contact with the curled portion 31. Further, the connecting portion 12 between the top plate portion 11 and the skirt portion 13 of the shell 10 is formed in a step portion 18 including a reduced diameter portion 18a and a shoulder portion 18b by drawing. The outer annular rib 24 of the liner 20 is the largest outer diameter portion of the curled portion 31 having a curved surface that bulges outward with respect to the neck 3 (the outer peripheral surface of the curled portion 31 at the height of the curl center O). ) To the lower side of the curled portion 31, and to the inclined wall 32 below the curled portion 31, and to the shell 10 of the cap 1, the step portion 18 between the top plate portion 11 and the skirt portion 13. Is closely attached to the lower side of the shoulder 18b.

  In the state where the cap 1 is attached to the mouth / neck portion 3, the lower end of the close contact portion of the outer annular rib 24 that is in close contact with the curl portion 31 has a maximum outer diameter of the curl portion 31 due to the balance between sealing performance and openability. It is preferable that the distance L in the horizontal direction (mouth neck radial direction) is in the range of 0.1 to 0.4 mm inward from the part, and if it is smaller than 0.1 mm, the sealing performance is inferior. When it is larger than 0.4 mm, the opening performance is inferior.

Further, regarding the hardness of the liner 20, when the hardness of the resin is too high in view of the general stoppering pressure when the cap is attached to the bottle-type can and the buckling strength of the can, the state shown in FIG. 3 and 4 , it becomes difficult to elastically deform the liner 20. On the other hand, if the hardness of the resin is too soft, even if the liner 20 is elastically deformed to the state shown in FIGS. Since it becomes difficult to maintain the sealing performance when the internal pressure of the can is increased or when it is dropped, it is preferable to set the hardness within the range of D hardness (ASTM D2240) 5-15.

According to the sealing liner structure of the threaded can cap of the present embodiment as described above, the outer annular rib 24 of the liner 20 is in close contact with the shell 10 below the shoulder portion 18b of the step portion 18. Thus, the liner 20 is firmly fixed and held at the close contact portion that is in close contact with the curled portion 31 below the maximum outer diameter portion, and the close contact portion that is in close contact with the inclined wall 32 below the curl portion 31 to ensure a close contact state. As a result, even if the top plate portion 11 of the cap 1 is displaced up and down due to a change in the internal pressure of the can or when the cap 1 is deformed due to dropping or the like, the liner 20 and the neck portion of the cap It is possible to sufficiently secure the sealing performance of the can by the three curled portions 31.

In addition, the outer annular rib 24 of the liner 20 and the upper end portion 19a of the vent hole portion 19 are in contact with each other in a state where the cap 1 is attached to the mouth-and-neck portion 3, so that the top plate portion of the cap 1 is caused by the internal pressure of the can. The outer annular rib 24 of the liner 20 can be more securely fixed and held by the upper end portion 19a of the vent hole portion 19 when the bulge 11 is bulged outward, and gas leakage from the vent hole portion 19 can be prevented. The outer annular rib 24 can prevent the deterioration of the sealing performance, and the cap 1 can be slightly rotated in the opening direction to loosen the threaded engagement with the mouth and neck portion 3. This can be prevented by contact friction between the outer annular rib 24 and the upper end portion 19a of the vent hole portion, and it is possible to reliably prevent deterioration of the sealing performance due to loosening of the screw connection between the cap 1 and the mouth neck portion 3. .

Further, in the cap (pill fur proof cap) 1 in which the lower end portion of the skirt portion 13 is the pill fur proof ring 17, the cap 1 attached to the mouth neck portion 3 in an unopened state is intentionally opened. By slightly turning in the direction, there is a risk of mischief such as leaking gas in the can without breaking the weakened portion 16 of the pill fur proof ring 17, whereas the liner 20 of the cap 1 By bringing the outer annular rib 24 into contact with the upper end portion 19a of the vent hole portion 19 of the mouth-and-neck portion 3, the cap 1 is intentionally turned slightly in the opening direction with respect to the mouth-and-neck portion 3 by contact friction between the two. It becomes difficult to move (the cap 1 does not rotate at all when the force is weak, and the cap rotates until the weakened portion 16 of the pilfer proof ring 17 breaks when the force is applied). Et al, the result, it is possible to prevent such mischievous, can increase the pilfer-proof effect.

In the present embodiment, the outer wall 22a and the outer annular rib 24 of the inner annular rib 22 are simply covered with the cap 1 on the mouth and neck 3 of the can 2 (the state before being attached to the mouth and neck 3). The inner side wall 24a is inclined so as to have a mountain shape in the longitudinal section with the annular flat surface 23 therebetween as a top, and the inner annular rib 22 is radially inward from the curl center O of the curled portion 31 of the mouth and neck portion 3. Is located, and the outer annular rib 24 is located radially outward. In such a state, only the inner wall 24 a of the outer annular rib 24 is in contact with the curled portion 31, but in some cases, only the inner wall 22 a of the inner annular rib 22 is in contact with the curled portion 31. Alternatively, both the inner wall 24a of the outer annular rib 24 and the inner wall 22a of the inner annular rib 22 may be brought into contact with the curled portion 31.

Having described an embodiment of a sealing liner structure of threaded cans cap of the present invention, the sealing liner structure of such a threaded cans cap of the present invention, the present as shown in FIGS. 3 and 4 When the internal pressure of the can was changed using the example and each comparative example as shown in FIGS. 5 to 7 (FIG. 5 = Comparative Example 1, FIG. 6 = Comparative Example 2, FIG. 7 = Comparative Example 3). An instantaneous pressure resistance test was conducted as an inspection of the sealing performance of the test piece, and a falling weight test was conducted as an inspection of the sealing performance when the can container was inverted and dropped. In addition, each Example and each comparative example differ only in the shape of each liner as shown in figure, and the material and hardness of resin of each liner are all the same.

For the instantaneous pressure resistance test, 9 kg at a speed of 0.35 kg / cm ² / s after the cap was attached to the mouth and neck master jig created in the same shape as the mouth and neck of the bottle-shaped can After pressurizing up to / cm ² and storing at room temperature (RT) and 60 ° C respectively for 1 day, 6 days, and 15 days, check for leaks, and determine that there is a leak. The ratio of the number of defects in the number of samples in each sample was investigated. The results are as shown in Table 1 below.

Be seen from Table 1 above, embodiments of the present invention as shown in FIGS. 3 and 4, as compared with the comparative example as shown in FIGS. 5 to 7 (Comparative Examples 1 to 3), the can internal pressure It can be seen that it has excellent sealing properties when changed.

For the drop weight test, while dropping liquid nitrogen into a bottle-shaped aluminum can (500 ml) with an outer diameter of the mouth and neck of about 28 mm, the internal pressure of the can is about 0.098 Mpa (1 kg / cm ² ) at room temperature. Adjusted], capped with hot water at 90 ° C., and capped with a test cap (capping load 883N, pressure block drawing diameter × drawing depth: φ26.35 mm × 2.2 mm, using Shibazaki # 501 capper), After retort sterilization at 125 ° C and / or 130 ° C for 30 minutes and cooling, after dropping from 10cm, 20cm, and 30cm height on an iron surface of 10 ° and 20 °, check for leakage The ratio of the number of defects in the number of samples in each sample was investigated. The results are as shown in Table 2 below.

Be seen from Table 2 above, embodiments of the present invention as shown in FIGS. 3 and 4, as compared with the comparative example as shown in FIGS. 5 to 7 (Comparative Examples 1-3), the can container It can be seen that it has excellent sealing performance when it is inverted and dropped.

About one Example of the sealing liner structure of the cap for screwed cans of this invention, The cap (the unused state before mounting | wearing) to which the liner was attached, and the mouth-and-neck part of the screwed can to which this cap is mounted | worn The partial cross section side view shown. 1 is an enlarged cross section showing the relationship between the cap liner and the can neck of the can in a state where the cap shown in FIG. Figure. The expanded sectional view which shows the relationship between the liner of a cap and the mouth neck of a can in the state which mounted | wore the mouth and neck of a screwed can with the cap shown in FIG. 1 by the longitudinal cross-section which does not pass the part of a vent hole part . The expanded sectional view which shows the relationship between the liner of a cap and the mouth neck of a can in the state which mounted | wore the mouth neck of a screwed can with the cap shown in FIG. 1 by the longitudinal cross section which passes through the part of a vent hole part. The expanded sectional view which shows the relationship between the liner of a cap and the mouth neck part of a can in the state which mounted | wore the cap neck part of the screwed can about the comparative example (comparative example 1) with respect to this invention. The expanded sectional view which shows the relationship between the liner of a cap and the mouth neck part of a can in the state which attached the cap to the mouth neck part of a threaded can about the comparative example (comparative example 2) with respect to this invention. The expanded sectional view which shows the relationship between the liner of a cap, and the mouth neck part of a can in the state which mounted | wore the cap neck part of the screwed can about the comparative example (comparative example 3) with respect to this invention.

DESCRIPTION OF SYMBOLS 1 Cap 2 Can 3 Mouth neck part 10 Shell 11 Top plate part 12 (Between a top plate part and a skirt part) Connection part 13 Skirt part 16 Weakening part 17 Pilfer proof ring 18 (Between a top board part and a skirt part ) Step
18a (stepped portion) shoulder 19 vent hole portion 19a upper end portion (of vent hole portion) 20 liner 22 (inner liner) inner annular rib 22a inner annular rib outer wall 23 (in liner) annular flat surface 24 (in liner) ) Outer annular rib 24a Inner side wall of outer annular rib 31 Curled portion 32 Inclined wall 33 Screw portion

Claims (5)

A cap made of a thin metal plate shell with a skirt portion suspended from the periphery of the top plate portion via a connecting portion, and an elastically deformable resin liner attached to the inner surface of the top plate portion of the shell, When the shell is mounted on the mouth and neck of the can in which the curled part, the inclined wall, and the screw part are formed in order from the bottom to the bottom of the shell, the screw is formed in the skirt part of the shell in accordance with the screw of the mouth and neck part. In a cap for a screwed can that is formed in a stepped part by drawing the connecting part between the top plate part and the skirt part, the resin liner is placed outward with the cap attached to the mouth and neck part. The curled part has a curved surface that bulges to the lowermost diameter of the curled part, adheres to the inclined wall below the curled part, and from the shoulder part of the step between the top plate part and the skirt part. together also in close contact with the shell to the lower, the cap shell script In the vicinity of the upper end of the seat portion, vent hole portions that are recessed inwardly and opened at the upper cut portion are formed at a plurality of locations along the circumferential direction, and with the cap attached to the mouth and neck portion, A sealed liner structure for a threaded can cap, characterized in that a resin liner is configured to come into contact with an indented upper end portion of each vent hole portion .   The resin liner has two annular ribs arranged concentrically across an annular flat surface, and the cap is placed on the mouth and neck before the cap is attached to the mouth and neck. Then, the outer wall of the inner annular rib and the inner wall of the outer annular rib are inclined so as to form a mountain shape in the longitudinal section with the annular flat surface therebetween as the top, and the radius from the curl center of the curl portion of the mouth and neck portion 2. The sealing liner structure for a threaded can cap according to claim 1, wherein an inner annular rib is located on the inner side in the direction and an outer annular rib is located on the outer side in the radial direction.   With the cap attached to the mouth and neck, the lower end of the close contact portion of the liner that is in close contact with the curl portion below the maximum outer diameter portion of the curl portion is 0.1 to 0.4 mm in the horizontal distance. The sealing liner structure of the cap for screwed cans according to claim 1 or 2, wherein the sealing liner structure is in the range of.   4. The sealed liner structure for a cap with a screw according to claim 1, wherein the hardness of the resin liner is in the range of D hardness (ASTM D2240) 5-15. Cap is a pilfer proof cap, the lower end portion of the skirt portion of the shell of the cap, in any one of claims 1 to 4, characterized in that has a pilfer-proof ring having a weakened portion breakable The sealing liner structure of the cap for threaded cans as described.

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