JP2007001619A - Sealing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing method for sealing a neck part of a container by using a container lid consisting of a thin metal plate shell and a synthetic resin packing, which is capable of enhancing the impact resistance, and preventing the sealing from being damaged even if a considerably large impact is applied to a shoulder area of the shell. <P>SOLUTION: In the sealing method, the shoulder area of the shell is deformed inward and downward in the radial direction at a plurality of pressing parts 68 at circumferential intervals in place of the deformation thereof inward and downward in the radial direction over the entire circumferential direction. At a plurality of the pressing parts, a packing is pressed against an outer circumferential surface at the upper end and the upper surface of a neck part of a container by the deformation of the shell, while, at non-pressed parts 70 between a plurality of pressing parts, a space 72 is present between the shell and the packing. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sealing method for sealing a mouth and neck of a container by attaching a container lid formed of a thin metal shell and a synthetic resin packing to the mouth and neck of the container.

  As is well known, recently, as a container for beverages such as coffee, it has a mouth and neck part in which a curl is formed at the upper end and a male thread and a locking jaw part are formed on the outer peripheral surface. Metal thin plate containers are widely used in practical use. As a container lid particularly suitable for such a metal sheet container, for example, as disclosed in Patent Documents 1 and 2, a container cover composed of a metal sheet shell and a synthetic resin packing is used. ing. The shell has a circular top wall and a skirt wall depending from the periphery of the top wall. The skirt wall is formed with a circumferential break line extending in the circumferential direction, and the skirt wall is divided into a main part above the circumferential break line and a tamper evidence skirt below the circumferential break line. Has been. The packing has a disk shape as a whole.

When sealing the mouth and neck by attaching a container lid to the mouth and neck of the container, the container lid is fitted on the mouth and neck and pressed downward, and the skirt wall extends from the periphery of the top wall of the shell. The shoulder region leading to the upper end of the sleeve is deformed radially inward and downward to bring the packing into close contact with the mouth and neck. While maintaining this state, a female thread is formed in the main part of the skirt wall of the shell corresponding to the male thread of the mouth and neck, and the lower part of the tamper evidence hem is also deformed radially inward. Lock to the jaw of the mouth and neck. When opening the mouth and neck, rotate the container in the opening direction. Thus, since the female thread of the shell is moved along the male thread of the mouth and neck, the container lid is raised with the rotation. However, the tamper evidence hem is prevented from rising because the lower part is locked to the locking jaw of the mouth and neck, and therefore considerable stress is generated in the circumferential break line, and the circumferential break line breaks. As a result, the tamper evidence hem is separated from the main part of the skirt wall. After that, the tamper evidence hem is left in the mouth and neck, the container lid is raised with rotation, is detached from the mouth and neck, and the mouth and neck are opened. If an axial break line is formed at the tamper evidence hem, a portion of the circumferential break line is maintained without breaking, the axial break line is broken, and the tamper evidence skirt is The container lid is developed from an endless annular shape to an end-band shape, and the entire container lid including the tamper evidence skirt is detached from the mouth and neck.
JP 2001-139053 A Japanese Patent Laid-Open No. 2003-175972

  Thus, according to the experience of the present inventors, the container lid composed of the thin metal shell and the synthetic resin packing is mounted on the mouth and neck of the container without being limited to the container lid of the above-described form. When the container's mouth and neck are sealed, for example, when a container with a container lid attached to the mouth and neck is dropped to the floor surface in a substantially inverted state and a considerable impact is applied to the shoulder region in the shell of the container lid It has been found that although the sealing damage is fine, it progresses gradually, and after several weeks, for example, it tends to become clear that the sealing of the mouth and neck is damaged. The phenomenon that it becomes clear that the sealing has been damaged after a relatively long time has passed since the impact was applied is generally referred to as “slow leak” or “micro leak”.

  The present invention has been made in view of the above-mentioned facts, and its main technical problem is to seal the mouth and neck of the container using a container lid composed of a thin metal plate shell and a synthetic resin packing. To improve the impact resistance by improving the method so that the seal is not damaged even if a substantial impact is applied to the shoulder region of the shell.

  As a result of diligent study, the inventors of the present invention, instead of deforming the shoulder region of the shell radially inward and downward over the entire circumferential direction, in a plurality of pressing portions spaced in the circumferential direction in the radial direction It is deformed inward and downward, and the packing is pressed against the upper and outer peripheral surfaces and the upper surface of the mouth and neck of the container by the deformation of the shell in the plurality of pressing parts, but in the non-pressing part between the plurality of pressing parts It has been found that the main technical problem can be achieved by allowing a gap to exist between the shell and the packing.

That is, according to the present invention, as a sealing method for achieving the main technical problem, a sealing method for sealing the mouth and neck by attaching a container lid to the mouth and neck of the container, the container lid is made of metal. In a sealing method comprising a thin plate shell and a synthetic resin packing, the shell having a circular top wall and a skirt wall depending from the peripheral edge of the top wall, the packing having a disk shape as a whole ,
After the container lid is fitted on the mouth and neck, the shoulder region extending from the peripheral edge of the top wall to the upper end of the skirt wall has a radius at a plurality of circumferentially spaced pressing portions. The packing is pressed against the outer peripheral surface and the upper surface of the upper end of the mouth and neck of the container by the deformation of the shell in the plurality of pressing portions. There is provided a sealing method characterized in that a gap exists between the shell and the packing in the non-pressing portion.

  Preferably, the circumferential width W1 of the pressing portion is 1 to 10 times the circumferential width W2 of the non-pressing portion. It is preferable that there are 4 to 12 non-pressing portions. In a preferred embodiment, the container is made of a thin metal plate, and a curl is formed on the upper end of the mouth and neck. The packing is conveniently non-adhering to the shell. Further, it is advantageous that the packing has a disk-shaped main wall portion and an outer seal ring that hangs down from the lower surface of the peripheral edge of the main wall portion and is brought into close contact with the outer peripheral surface of the upper end of the mouth-neck portion.

  According to the sealing method of the present invention, as clearly understood from the examples and comparative examples described later, the impact resistance is improved, and the seal is damaged even if a considerable impact is applied to the shoulder region of the shell. Is sufficiently suppressed or avoided. The reason why the impact resistance is improved by attaching the container lid to the mouth and neck of the container by the sealing method of the present invention is not necessarily clear, but the shell protrudes locally at the plurality of non-pressed parts. And there is a gap between the shell and the packing, so if an impact is applied to the shoulder area of the shell, the shell will be locally deformed in the non-pressed part, thereby buffering the impact. It is estimated that there is.

  Hereinafter, preferred embodiments of a sealing method constructed according to the present invention will be described in more detail with reference to the accompanying drawings.

  FIG. 1 shows a typical example of a container lid used in a preferred embodiment of the sealing method of the present invention. The illustrated container lid, generally indicated by numeral 2, includes a shell 4 formed of a suitable metal thin plate such as an aluminum-based alloy thin plate, and a suitable synthetic resin such as styrene elastomer and polypropylene separately from the shell 4. And a packing 6 made of a blend resin.

  The shell 4 has a circular top wall 8 and a skirt wall 10 that is generally cylindrical and hangs down from the periphery of the top wall 8. The peripheral portion of the top wall 8 is connected to the upper end portion of the skirt wall 10 via a boundary portion having an arc shape in the sectional view. The top wall 8 has a circular central immersive portion 12 that extends substantially horizontally, an intermediate portion 14 having an inverted frustoconical shape, and an outer annular portion 16 that extends substantially horizontally. The peripheral portion of the top wall 8 (ie, the radially outer portion of the outer annular portion 16), the boundary between the top wall 8 and the skirt wall 10, and the upper end of the skirt wall 10 constitute a shoulder region 11 of the shell 4. A circumferential break line 18 is formed in the lower part of the skirt wall 10, and the skirt wall 10 has a main portion 20 above the circumferential break line 18 and a tamper evidence skirt 22 below the circumferential break line 18. It is divided into and. In the illustrated embodiment, an annular bulging portion 24 is formed at the lower portion of the skirt wall 10, and the annular bulging portion 24 is provided with a slit 26 extending in the circumferential direction at intervals in the circumferential direction and between the slit 26. The circumferential direction fracture | rupture line 18 comprised from the bridge part 28 which exists in this is arrange | positioned. An annular groove 30 is formed in the main portion 20 of the skirt wall 10. In addition, a plurality of vent holes 32 are disposed above the annular groove portion 30 at intervals in the circumferential direction. Each of the vent holes 32 forms a lateral slit 34 that extends substantially horizontally at intervals in the circumferential direction, and generates an inward displacement portion 36 by forcing the lower portion of the lateral slit 34 radially inward. It is formed by doing.

  The description will be continued with reference to FIG. 1. The packing 6 has a disc shape as a whole, and has a central immersive portion 38 that extends substantially horizontally, an intermediate portion 40 having an inverted frustoconical shape, and a peripheral edge portion 42. The upper surface of the peripheral edge portion 42 extends substantially horizontally outward in the radial direction, and then extends radially outward and downward in an arc shape in the cross-sectional view. Two annular seal rings, that is, an annular outer seal ring 44 and an annular inner seal ring 46 are formed on the lower surface of the peripheral edge 42 of the packing 6. The outer portion of the peripheral edge portion 42 of the packing 6 is increased in thickness, and the outer seal ring 44 is extended downward from the outer portion where the thickness is increased. An annular receiving surface 48 that extends substantially horizontally is defined radially outward of the outer seal ring 44. An inner seal ring 46 that is spaced radially inward with respect to the outer seal ring 44 extends downward from the inner side of the peripheral edge 42. Such a packing 6 is inserted into the shell 4, and the outer peripheral edge of the packing 6 is elastically deformed so that the annular receiving surface 48 passes through the inward displacement portion 36 in the shell 4 and is positioned above it. It is done.

  FIG. 2 also shows the mouth / neck portion 50 of the container to which the container lid 2 is applied together with the container lid 2 described above. The mouth / neck portion 50 of the container, which can be formed from a chromic acid-treated steel sheet, an aluminum-based alloy sheet, or a tin sheet, has a substantially cylindrical shape as a whole, and a male thread 52 is formed at the center in the axial direction. A locking jaw 54 having an annular bulging shape is formed below the male thread 52. The upper part of the mouth-and-neck part 50 has a truncated cone shape whose diameter gradually decreases upward, and an outer curl 56 is formed at the upper end of the mouth-and-neck part 50. The curl 56 extends upward in the cross-sectional view, extends in an arc shape upward and radially outward, extends in an arc shape downward and radially outward, extends downward, and downwards and radially inward. It extends in a circular arc shape and further extends in a circular arc shape upward and inward in the radial direction. Since the metal container itself provided with such a mouth-and-neck part 50 is well known, detailed description of the metal container itself is omitted in this specification.

  A preferred embodiment of the sealing method of the present invention, that is, a preferred embodiment of the sealing method for sealing the mouth and neck 50 by attaching the container lid 2 to the mouth and neck 50 of the container is as follows. When the contents to be filled in the container are coffee, normally, after filling the container with coffee, nitrogen gas is introduced into the container to remove the air in the upper space of the container from the container. At the same time, water vapor is introduced into the container, and then the container lid 2 is fitted onto the mouth-and-neck portion 50. When the water vapor is liquefied due to the temperature drop, the inside of the container fitted with the container lid 2 is decompressed, and the container lid 2, particularly its packing 6, is sucked by this decompression, and as shown in FIG. The inner seal ring 46 is advanced into the mouth-and-neck portion 50, and thus the mouth-and-neck portion 50 is temporarily sealed. In such a state, the packing 6 is raised relative to the shell 4, and the upper surface of the peripheral edge 42 of the packing 6 is brought into contact with the inner surface of the outer annular portion 16 in the top wall 8 of the shell 2.

  Next, as shown in FIG. 3, the pressing tool 58 is applied to the container lid 2 to press the container lid 2 downward, and the shoulder region 11 of the shell 4 is deformed radially inward and downward, thus the packing 6. Is brought into close contact with the mouth-neck portion 50 of the container. In the sealing method of the present invention, the shoulder region 11 of the shell 4 is not deformed radially inward and downward over the entire circumferential direction, but the shell 4 is pressed at a plurality of circumferentially spaced pressing portions. The shoulder region 11 of the shell 4 is deformed radially inward and downward to press the punkin 6 against the mouth-and-neck portion 50, but the shoulder region 11 of the shell 4 is deformed in the non-pressed portion existing between the plurality of pressed portions. It is important to leave a gap between the shell 4 and the punkin 6 without or reducing the degree of deformation.

  4 and FIG. 5 together with FIG. 3, the illustrated pressing tool 58 includes a horizontal pressing surface 60 extending substantially horizontally, and radially outward from the outer peripheral edge of the horizontal pressing surface 60. A main inclined pressing surface 62 that is inclined downward, a vertical pressing surface 64 that extends substantially vertically downward from an outer peripheral edge of the inclined pressing surface 62, and an inclined downward extending radially outward from the lower end of the vertical pressing surface 64. An outer inclined pressing surface 65 is provided. However, as clearly understood from FIG. 4, the main inclined pressing surface 62, the vertical pressing surface 64, and the outer inclined pressing surface 65 do not continuously extend in the circumferential direction. It is interrupted by eight notches 66 positioned at equal angular intervals. Accordingly, the shoulder region 11 of the shell 4 is displaced radially inward and downward in the pressing portion 68 corresponding to the eight portions other than the notch portion 66 of the pressing tool 58, and in the pressing portion 68, the shell 4 is displaced. The shoulder region 11 is brought into intimate contact with the packing 6, and the packing 6 is pressed against the mouth-and-neck portion 50, particularly the outer peripheral surface and upper surface of the upper end thereof. However, in the non-pressing portion 70 corresponding to the eight notches 66, the shoulder region 11 of the shell 4 is not deformed radially inward or downward, so that the shoulder region 11 of the shell 4 and the packing 8 are not deformed. A gap 72 is left between them. The circumferential width W1 of the pressing portion 68 is 1 to 10 times the circumferential width W2 of the non-pressing portion 70, and it is preferable that there are 4 to 12, and particularly 6 to 10, non-pressing portions 70.

  When the container lid 2 is attached to the mouth-and-neck portion 50 of the container, as shown in FIG. 3, a thread forming tool 74 is further applied to the skirt wall 10 of the shell 4 so that the annular groove portion 30 (FIG. 1). A female thread 76 is formed along the male thread 52 of the mouth-and-neck section 50 from the bottom to the bottom. Further, a locking tool 78 is applied to the lower part of the tamper evidence skirt 22 of the skirt wall 10 to force the lower part of the tamper evidence skirt 22 radially inward to lock the jaws of the mouth and neck 50. 54. The configuration of the thread forming tool 74 and the locking tool 78, and also the capping by them may be in a form well known to those skilled in the art, and therefore a detailed description thereof will be omitted in this specification. As described above, in a state where the container lid 2 is mounted on the mouth / neck portion 50 of the container, the upper edge of the inward displacement portion 36 formed on the skirt wall 10 of the shell 4 and the annular receiving surface 48 of the packing 6. There is an interval Y (FIG. 5) that is preferably about 0.3 to 3.5 mm between them, and the outer peripheral edge of the annular receiving surface 48 of the packing 6 is the upper edge of the inward displacement portion 36 of the shell 4. It is positioned radially outward by a distance Z (FIG. 5) that may be about 0.1 to 1.0 mm from the minimum inner peripheral edge.

  Continuing the description with reference to FIG. 6 illustrating the state in which the container lid 2 is attached to the mouth / neck portion 50 as required, if the content filled in the container is coffee, it is usually as described above. After attaching the container lid 2 to the mouth and neck part 50, the container is heated to about 130 ° C. under a pressure of 0.13 MPa, for example, and sterilized by retort. To do. The cooling water sprayed into the container enters the shell 4 through the vent holes 32 formed in the skirt wall 10 of the shell 4, but the upper surface of the peripheral edge 42 of the packing 6 is the outer annular portion of the top wall 8 of the shell 4. Since it is in close contact with the inner surface of 16, the cooling water is reliably prevented from entering between the central immersive portion 12 of the top wall 8 of the shell 4 and the central immersive portion 38 of the packing 6.

  When the container neck 50 is opened and the contents are consumed, the shell 4 of the container lid 2 is rotated in the opening direction, that is, counterclockwise as viewed from above in FIG. Thus, the shell 4 is raised along with the rotation by the cooperation of the male thread 52 of the mouth and neck portion 50 and the female thread 76 of the shell 4. However, the tamper-evidence skirt portion 22 of the shell 4 is locked to the locking jaw portion 54 of the mouth-and-neck portion 50, so that the rise is prevented, and the circumferential direction formed on the skirt wall 10 of the shell 4 thereby. A considerable stress is generated in the bridging portion 28 of the breaking line 18, and the circumferential breaking line 18 is broken. When the circumferential break line 18 is broken, the packing 6 that is in close contact with the mouth and neck portion 50 is formed separately from the shell 4, and therefore is in close contact with the mouth and neck portion 50. Since only the shell 4 can be rotated without accompanying rotation of the packing 6, the circumferential break line 18 can be broken sufficiently easily without requiring excessive torque.

  After the circumferential break line 18 is broken, the tamper evidence skirt 22 remains, and the top wall 8 of the shell 4 and the main portion 20 of the skirt wall 10 are raised with rotation. When the top surface wall 8 of the shell 4 and the main portion 20 of the skirt wall 10 are raised over the distance Y, the upper edge of the inward displacement portion 36 generated in the shell 4 becomes an annular receiving surface 48 of the packing 6. It can be brought into contact. After that, the packing 6 is also lifted as the top surface wall 8 of the shell 4 and the main portion 20 of the skirt wall 10 are lifted, so that the packing 6 is separated upward from the mouth-and-neck portion 50 and the mouth-and-neck portion. 50 is released, and the packing 6 is detached from the mouth and neck portion 50 together with the top surface wall 8 of the shell 4 and the main portion 20 of the skirt wall 10, and the mouth and neck portion 50 is opened. The packing 6 is separated upward from the mouth-and-neck part 50 and the sealing of the mouth-and-neck part 50 is released. The circumferential break line 18 in the shell 4 is broken, and the main wall 8 and the skirt wall 10 of the shell 4 are broken. After the portion 20 is raised over the interval Y, the sealing of the mouth-and-neck portion 50 is not released prior to the breaking of the circumferential break line 18.

  When only a part of the contents of the container is consumed, the packing 6 held therein together with the top surface wall 8 of the shell 4 and the main portion 20 of the skirt wall 10 separated from the mouth-and-neck portion 50 are placed in the mouth-and-neck. The female thread 76 of the shell 4 is screwed onto the male thread 52 of the mouth and neck part 50 again, and thus the mouth and neck part 50 can be temporarily sealed.

  In the above-described embodiment, when opening the mouth-and-neck portion 50, the circumferential break line 18 formed in the skirt wall 10 of the shell 4 is broken over the entire circumferential direction, and the tamper-evident skirt portion 22 is formed. It is completely separated from the main part 20 of the skirt wall 10, but when desired, when one or more axial break lines are provided at the tamper evidence skirt 22 and the mouth and neck part 50 is opened. The circumferential rupture line is not completely ruptured, but part of it remains, and the axial rupture line is ruptured so that the tamper evidence hem is developed from an endless annular shape to an end band shape. The entire shell 4 including the hem portion can be detached from the mouth-and-neck portion 50.

Next, examples and comparative examples of the present invention will be described.
EXAMPLE A container lid having the form shown in FIG. 1 was produced. The produced container lid is a container lid for containers with a nominal diameter of 38 mm for the neck and neck, the shell is formed from an aluminum thin plate with a thickness of 0.25 mm, and the packing is a blend resin of styrene elastomer and polypropylene Formed from.

  A container sold by Toyo Seikan Co., Ltd. under the trade name “TEC200” (having a mouth-and-neck portion in the form as shown in FIG. 2, having a nominal diameter of 38 mm and a nominal volume of 200 ml, Filled with 190 ml of 90 ° C. water in a chrome sun-treated steel sheet container with a thermoplastic resin coating on both sides), and further supplies nitrogen and water vapor to the remaining space of the container (so-called head space) to replace the air, And the container lid was mounted | worn with the mouth-and-neck part of the container by the mounting | wearing style as illustrated in FIG. 3, and the mouth-and-neck part was sealed. At this time, a force of 1400 N was applied to the pressing tool. The filling amount of water vapor is such that the theoretical reduced pressure value in the container when the water vapor is cooled to room temperature is 35 to 40 kPa. The pressing tool is formed with eight notches at equiangular intervals in the circumferential direction, the circumferential width W2 of each notch (and hence the non-pressing part) is 3 mm, and between the notches (and thus the pressing part). The circumferential width W1 was 12 mm.

  Next, the following drop impact resistance test (this drop impact resistance test is an extremely severe test) was performed. A container lid was attached, the container was turned upside down, allowed to freely fall 30 cm through a vertical drop path, and collided with an iron cylindrical member whose upper surface was an inclined surface with an inclination angle of 10 degrees. Then, the mouth and neck of the container was immersed in a solution in which 13.2 g of methyl violet was mixed with 1000 ml of 2-butoxyethanol, and an external pressure of 0.1 MPa was applied for 30 minutes. Subsequently, the mouth and neck of the container was taken out of the solution and dried at room temperature and normal humidity for 24 hours (one day). Thereafter, the container lid was removed from the mouth and neck, the mouth and neck were opened, and the water in the container was observed. The solution is bluish purple, and when the solution is slightly sucked into the container, the water in the container is bluish purple. As a result of performing the drop impact resistance test as described above for 10 container lids, the water in the containers was bluish purple for 2 container lids, but the water in the containers was colorless for 8 container lids. It was confirmed that the sealing was not damaged by the drop impact.

  There is no notch in the pressing tool used to attach the container lid to the container neck and neck, so the shoulder area of the shell is deformed radially inward and downward over the entire circumferential direction. When the drop resistance test similar to that of the example was performed on 10 container lids, it was confirmed that the water in the containers was blue-violet in all 10 container lids, and the sealing was damaged by the drop impact. .

The front view which shows a part of typical example of the container lid used for the sealing method of this invention with sectional drawing. FIG. 2 is a front view partially showing a cross-sectional view of a state in which the container lid of FIG. The front view which shows a mounting | wearing mode which mounts the container lid of FIG. 1 on the mouth neck part of a container according to suitable embodiment of the sealing method of this invention, and seals a mouth neck part in sectional drawing. The bottom view of the pressing tool shown in FIG. The elements on larger scale which expand and show a part of mounting | wearing style shown in FIG. The front view which shows a state with which the container neck shown in FIG. 1 was mounted | worn to the mouth neck part of the container, and the mouth neck part was sealed, partially in sectional drawing.

Explanation of symbols

2: Container lid 4: Shell 6: Packing 8: Shell top wall 10: Shell skirt wall 50: Container neck and neck 58: Press tool 60: Press tool notch 68: Press part 70: Non-press part

Claims (6)

A sealing method in which a container lid is attached to a mouth and neck of a container to seal the mouth and neck. The container lid includes a thin metal shell and a synthetic resin packing, and the shell is a circular ceiling. A sealing method comprising a face wall and a skirt wall depending from the peripheral edge of the top wall, wherein the packing is generally disc-shaped;
After the container lid is fitted on the mouth and neck, the shoulder region extending from the peripheral edge of the top wall to the upper end of the skirt wall has a radius at a plurality of circumferentially spaced pressing portions. The packing is pressed against the outer peripheral surface and the upper surface of the upper end of the mouth and neck of the container by the deformation of the shell in the plurality of pressing portions. A sealing method, wherein a gap exists between the shell and the packing in the non-pressing portion.   The sealing method according to claim 1, wherein the circumferential width W1 of the pressing portion is 1 to 10 times the circumferential width W2 of the non-pressing portion.   The sealing method according to claim 1, wherein there are 4 to 12 non-pressing portions.   The sealing method according to any one of claims 1 to 3, wherein the container is made of a thin metal plate, and a curl is formed at an upper end of the mouth and neck.   The sealing method according to claim 1, wherein the packing is non-adhered to the shell.   6. The packing according to claim 1, wherein the packing has a disk-shaped main wall portion and an outer seal ring that hangs down from the lower surface of the peripheral edge of the main wall portion and is in close contact with the outer peripheral surface of the upper end of the mouth-neck portion. The sealing method as described.

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