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Title:
METHOD AND DEVICE FOR INSPECTING WELDING STRENGTH OF PACKAGING CONTAINER CAP
Document Type and Number:
WIPO Patent Application WO/2021/122244
Kind Code:
A1
Abstract:
After a predetermined time following completion of welding to a cap, temperatures in regions on the surface of the cap corresponding to a plurality of leg portions of a linking portion for linking an inner cover and the cap are measured, and when all of the temperatures are within a predetermined range in which sufficient welding strength is demonstrated for the inner cover to be released from the packaging container at the same time as the cap, the welding strength is deemed to be sufficient, and when said temperatures are outside said temperature range, the welding strength is deemed to be insufficient.

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Inventors:
MORIYAMA YASUYUKI (JP)
Application Number:
PCT/EP2020/085373
Publication Date:
June 24, 2021
Filing Date:
December 09, 2020
Export Citation:
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Assignee:
TETRA LAVAL HOLDINGS & FINANCE (CH)
International Classes:
B29C65/82; B29C65/36; B29C65/56; B29C65/72; G01M3/00; G01N25/72; B65D51/22
Domestic Patent References:
WO2014178056A12014-11-06
Foreign References:
EP2886479A12015-06-24
EP3214005A12017-09-06
JP2017504534A2017-02-09
JP2002318213A2002-10-31
Attorney, Agent or Firm:
TETRA PAK - PATENT ATTORNEYS SE (SE)
Download PDF:
Claims:
CLAIMS [Claim 1]

Inspection method used in an unsealing device provided on a packaging container, said unsealing device comprising: an inner cover formed flush with the packaging container at the bottom portion of a spout protruding from the packaging container; a cap which mates with the outer circumference of the spout; a laminate comprising an aluminium foil layer and a plastic layer bonded to a bottom surface of the cap; and a linking portion comprising a plurality of leg portions which are formed as a single piece with the inner cover and extend from the inner cover in the direction of the cap, and an annular portion which is linked to said plurality of leg portions and abuts the laminate, the inner cover being joined to the cap via the linking portion by fusing the plastic layer to the cap by means of induction heating of the aluminium foil layer, and said unsealing device having a function with which, when the cap is opened, the inner cover is also released from the packaging container at the same time, wherein said inspection method comprises: a step in which, after a predetermined time following completion of the welding, temperatures in respective regions on the surface of the cap corresponding to the plurality of leg portions are measured; and a step in which, when the temperatures in all of the regions corresponding to the plurality of leg portions are within a predetermined temperature range, the welding strength is deemed to be sufficient, and when said temperatures are outside said temperature range, the welding strength is deemed to be insufficient.

[Claim 2]

Method for inspecting welding strength according to Claim 1, wherein the predetermined temperature range is determined on the basis of pre-measured temperature data relating to a plurality of unsealing devices in which the inner cover is also opened at the same time as the cap.

[Claim 3]

Method for inspecting welding strength according to Claim 1 or 2, wherein a temperature distribution obtained by imaging the whole surface of the cap using an infrared camera is divided into at least three regions, namely the predetermined temperature range, a temperature range higher than the predetermined temperature range, and a temperature range lower than the predetermined temperature range, and it is determined whether all of the temperatures in the respective regions corresponding to the plurality of leg portions are within the predetermined temperature range. [Claim 4]

Method for inspecting welding strength according to Claim 1 or 2, wherein the temperatures on the surface of the cap at the positions of the plurality of leg portions are measured by means of an infrared radiation thermometer, and it is determined whether all of the measurement temperatures are within the predetermined temperature range.

[Claim 5]

Inspection device for inspecting welding strength of an annular portion and a cap of an unsealing device comprising: an inner cover which is formed from plastic on a bottom portion of a plastic spout protruding from a packaging container filled with a beverage or a liquid food and hermetically sealed, the inner cover being flush with the packaging container; a cap which is mated with the outer circumference of the spout; a laminate comprising an aluminium foil layer and a plastic layer bonded to a bottom surface of the cap; and a linking portion comprising a plurality of leg portions which are formed as a single piece with the inner cover and extend from the inner cover in the direction of the cap, and an annular portion which is linked to said plurality of leg portions and abuts the laminate, the inner cover being joined to the cap via the linking portion by fusing the plastic layer to the cap by means of induction heating of the aluminium foil layer, and said unsealing device having a function with which, when the cap is opened, the inner cover is also released from the packaging container at the same time, wherein said inspection device includes: a means for measuring temperatures in respective regions on the surface of the cap corresponding to the plurality of leg portions, after a predetermined time following completion of the welding; a memory unit for pre-storing a predetermined temperature range in which the welding strength of the annular portion and the cap is sufficient for the inner cover to be released from the packaging container at the same time as the cap; a comparison unit for comparing the measured temperatures in the regions corresponding to the plurality of leg portions, and the predetermined temperature range; and a determination unit for determining that the welding strength is sufficient when all of the temperatures in the regions corresponding to the plurality of leg portions are within the predetermined temperature range, and for determining that the welding strength is insufficient when said temperatures are outside said temperature range.

[Claim 6]

Device for inspecting cap welding strength according to Claim 5, wherein the predetermined temperature range is determined on the basis of pre-measured temperatures relating to a plurality of unsealing devices in which the inner cover is also opened at the same time as the cap, and stored in the memory unit in said inspection device.

[Claim 7]

Inspection device according to Claim 5 or 6, wherein the means for measuring temperature includes: an infrared camera for imaging the whole surface of the cap; and an image processing device which performs imaging by dividing a distribution of the measured temperatures into at least three regions, namely the predetermined temperature range, a temperature range higher than the predetermined temperature range, and a temperature range lower than the predetermined temperature range.

[Claim 8]

Inspection device according to Claim 5 or 6, wherein the means for measuring temperature includes an infrared radiation thermometer for measuring the temperature on the surface of the cap at the positions of the plurality of leg portions.

Description:
[Title of the Invention] METHOD AND DEVICE FOR INSPECTING WELDING STRENGTH OF PACKAGING CONTAINER CAP

[Technical Field]

[0001]

The present invention relates to a method and a device for inspecting the welding strength of a cap in an unsealing device of the type in which an upper surface of a linking portion, which is formed as a single piece with an inner cover formed flush with a packaging container that has been filled with a beverage or liquid food and hermetically sealed, and a cap, which is mated with the outer circumference of a spout protruding from the packaging container, are welded, and when the cap is opened, the inner cover is also opened at the same time in conjunction therewith.

[Background Art]

[0002]

A large number of beverages and liquid foods such as tea, fruit and vegetable juices, milk and sauces are made commercially available by enclosing them in packaging containers formed from a sheet-like packaging material made of sterilized paper. Unsealing devices for extracting contents to the outside from the sterilized packaging containers must maintain a sterile interior state until the time of unsealing, and must also be easily unsealable with a small force at the time of unsealing. Unsealing devices with various structures comprising a lid, a spout and a linking portion, etc. have therefore been proposed.

[0003]

For example, a packaging container which has been conventionally used, comprising a pull-ring formed by moulding plastic on the packaging material and a lid which is mated with a spout enclosing the periphery of the pull-ring, has a structure in which, after the lid has been initially taken off, the pull-ring is pulled with a finger to remove an inner cover, thereby forming a hole in the packaging material. With this structure, however, there are times when the contents are accidentally ejected because of a reaction movement of the packaging container when the pull-ring is removed from the packaging material. In order to avoid this, the applicant of this case proposed an unsealing device of the type in which opening of a cap also opens the inner cover at the same time. (Patent Publication 1)

[0004]

Fig. 1 shows a cross section of the above unsealing device 1 in the direction of an axis A. A plastic spout 11 and a plastic linking portion 12 are preformed as a single piece at a forming position of the unsealing device 1 of a sheet-like packaging container 10, in such a way that a bottom portion thereof is flush with the packaging container 10. An annular groove 13 is formed at this bottom portion between an inner wall of the spout 11 and the linking portion 12 and has a smaller thickness than that of the surrounding portion, and a circular region enclosed by the annular groove 13 constitutes an inner cover 14. The linking portion 12 comprises two or more leg portions 15, a lower side of which is formed continuously with the inner cover 14, and an annular portion 16 which is contiguous with an upper end portion of said leg portions 15. A helical groove 22 mating with helical projections 21 provided on the outer circumference of the plastic spout 11 is formed on an inner circumferential surface of a cap 20, and an unsealing indication ring 23 which readily separates from a lid main body as a result of rotation of the cap 20 is formed at a bottommost portion of the cap 20. Furthermore, a laminate 19 comprising, from above, an aluminium foil layer and a layer of plastic such as polyethylene is fixed to a bottom surface of the cap 20. An upper surface of the annular portion 16 abuts the plastic layer of the laminate 19 when the cap 20 is closed. Fig. 2 is an exploded outline diagram to make the configuration of the unsealing device 1 clearer.

[0005]

In order to complete the unsealing device 1, from the state in fig. 3, the cap 20 is rotated fully onto the spout 11 to close same, after which an induction heating device 30 is placed in contact with an upper surface of the cap 20 and an electrical current is applied, at which point the aluminium foil layer of the laminate 19 on the bottom of the cap 20 generates heat as a result of electromagnetic induction, the plastic layer therebelow melts, and the bottom portion of the cap 20 and the annular portion 16 are welded and fixed as a result (fig. 4). When the cap 20 is rotated and opened after having been37 fixed, the linking portion 12 in which the annular portion 16, leg portions 15 and inner cover 14 are formed as a single piece can be detached from the container together with the cap 20, and the contents can be poured to the outside (fig. 5).

[0006]

However, variations in welding strength are produced in the welding process afforded by induction heating of the cap 20 and the annular portion 16, depending on the situation during production, and there are times when the linking portion 12 remains on the container even after removal of the cap 20, meaning that the inner cover does not open or only a portion of the inner cover opens. There are therefore times when it is desirable to inspect each individual packaging container for bonding strength of the unsealing device after the welding process.

[0007]

Furthermore, according to other prior art, Patent Publication 2 describes a method in which a bottom surface of a cap and an upper surface of a spout are welded by means of induction heating using a laminate comprising an aluminium foil layer and a plastic layer, the extent of welding and uniformity of the welded state are acquired as an infrared thermal image by means of an infrared camera, and said thermal image is compared with a thermal image of a favourable bonding state by an image inspection processing device so as to inspect whether the state of sealing of the cap is favourable. It is concluded in that document that if a thermal image of the surface of the cap shows a clean doughnut-shaped pattern at an upper end portion of the spout welded to the cap, then this constitutes a favourable sealing condition.

[Prior Art Documents]

[0008]

[Patent Publication 1] JP 2017-504534 A [Patent Publication 2] JP 2002-318213 A [Summary of the Invention]

[Problems to be Solved by the Invention]

[0009]

However, in an unsealing device to which the present invention is applied, the linking portion is provided between the inner cover and the cap, and the inner cover linked to the cap must also be removed by means of the linking portion at the same time as the cap is opened, so greater welding strength than in the case of Patent Publication 2 is needed between the upper surface of the linking portion and the cap which have been welded, and the cap and the inner cover must be linked with greater precision. Furthermore, the resin bottle cap according to Patent Publication 2 and the unsealing device for a packaging container formed from a sheet-like packaging material made of paper according to Patent Publication 1 belong to completely different technical fields, so the inspection method according to Patent Publication 2 cannot be used unmodified in an unsealing device to which the present invention is applied, as will be described later. [0010]

The aim of the present invention lies in providing a method for reliably and easily inspecting the welded state of an unsealing device of the type in which an upper surface of a linking portion formed as a single piece with an inner cover and a cap are welded, and when the cap is opened, the inner cover is also opened at the same time in conjunction therewith, and also in providing an inspection device.

[Means for Solving the Problems]

[0011]

In the method for inspecting the welding strength of an unsealing device according to the present invention, an aluminium foil/plastic laminate fixed to a bottom surface of a cap is caused to generate heat by electromagnetic induction in the aluminium foil layer by means of an electromagnetic induction heating device arranged on an upper side of the cap, and the plastic underlayer and an annular portion on the very top of a linking portion are welded, after which a temperature distribution on the surface of the cap in the region of the annular portion is acquired as an infrared thermal image using an infrared camera, and this thermal image is displayed in colour as a temperature distribution on the surface of the cap by means of an image processing device. As a result of detailed investigations into the relationship between temperature distribution on the surface of the cap and welding strength, the present inventor found that it is possible to determine the welding strength of the cap by means of a temperature pattern in the region of the annular portion, in particular in the region of leg portions mechanically linking the annular portion and the inner cover.

[0012]

The method for inspecting welding strength of an unsealing device according to the present invention is used in an unsealing device comprising: an inner cover which is formed on a bottom portion of a spout protruding from a packaging container filled with a beverage or a liquid food and hermetically sealed, the inner cover being flush with the packaging container; a cap which is mated with the outer circumference of the spout; a laminate comprising an aluminium foil layer and a plastic layer bonded to a bottom surface of the cap; and a linking portion comprising a plurality of leg portions which are formed as a single piece with the inner cover and extend from the inner cover in the direction of the cap, and an annular portion which is linked to said plurality of leg portions and abuts the laminate, the inner cover being joined to the cap via the linking portion by fusing the plastic layer to the cap by means of induction heating of the aluminium foil layer, and said unsealing device having a function with which, when the cap is opened, the inner cover is also released from the packaging container at the same time, wherein said inspection method includes: a step in which, after a predetermined time following completion of the welding, temperatures in respective regions on the surface of the cap corresponding to the plurality of leg portions are measured; and a step in which, when the temperatures in all of the regions corresponding to the plurality of leg portions are within a predetermined temperature range, the welding strength is deemed to be sufficient, and when said temperatures are outside said temperature range, the welding strength is deemed to be insufficient. It should be noted that the predetermined temperature range according to the present invention is a temperature range in which sufficient welding strength is demonstrated for the inner cover to be released from the packaging container at the same time as the cap.

[0013]

Furthermore, the abovementioned temperature range is determined from pre measured temperature data relating to a plurality of unsealing devices in which the inner cover is also opened at the same time as the cap.

[0014]

When the temperatures in the regions on the surface of the cap corresponding to the leg portions are measured, a temperature distribution obtained by imaging the whole surface of the cap using an infrared camera is divided into at least three regions, namely the predetermined temperature range, a temperature range higher than the predetermined temperature range, and a temperature range lower than the predetermined temperature range, and it is determined whether all of the temperatures in the respective regions corresponding to the plurality of leg portions are within the predetermined temperature range.

[0015]

Alternatively, the temperatures on the surface of the cap at the positions of the plurality of leg portions are measured by means of an infrared radiation thermometer, and it is determined whether all of the measurement temperatures are within the predetermined temperature range.

[0016]

The present invention also provides an inspection device for determining the welding strength of a cap.

The inspection device comprises, as a means for measuring temperature, an infrared camera for imaging the whole surface of the cap, and includes an image processing device which performs imaging by dividing a distribution of the measured temperatures into at least three regions, namely the predetermined temperature range, a temperature range higher than the predetermined temperature range, and a temperature range lower than the predetermined temperature range.

Alternatively, an infrared radiation thermometer for measuring the temperatures on the surface of the cap at the positions of the plurality of leg portions is provided as a means for measuring the temperature.

[0017]

Furthermore, the inspection device according to the present invention includes: a memory unit for storing a predetermined temperature range which is defined in advance on the basis of measured temperature data relating to a plurality of unsealing devices in which the inner cover is also opened at the same time as the cap; a comparison unit for comparing whether all of the temperatures in the respective regions corresponding to the plurality of leg portions are within the predetermined temperature range; and a determination unit for determining the welding strength as a result.

[Advantage of the Invention]

[0018]

The inspection method according to the present invention makes it possible to reliably and easily inspect the quality of welding strength between a cap and an inner cover. Additionally, the inspection method according to the present invention makes it possible to omit image processing outside of the leg portion regions because it is sufficient for the temperature in the leg portion regions to be measured, so it is possible to conduct the inspection more rapidly, and to simplify and reduce the size of the inspection device compared with the prior art.

[Brief Description of the Drawings]

[0019]

[Fig. 1] Fig. 1 is a view in longitudinal section of an unsealing device of a packaging container to which the present invention is applied.

[Fig. 2] Fig. 2 is an exploded diagram showing the configuration of the unsealing device.

[Fig. 3] Fig. 3 is an outline diagram showing a state before a cap of the unsealing device is closed.

[Fig. 4] Fig. 4 shows a state after the cap of the unsealing device has been closed, where an electromagnetic induction heating device is placed in contact therewith to provide heating. A cross section of only the unsealing device portion is shown.

[Fig. 5] Fig. 5 is an external view showing a state in which the cap has been opened after a linking portion of the unsealing device has been welded.

[Fig. 6] Fig. 6 schematically shows temperature distributions obtained by imaging an upper surface of the cap by means of an infrared camera, after the linking portion of the unsealing device has been welded.

[Mode for Implementing the Invention]

[Exemplary Embodiment 1]

[0020]

After production of an unsealing device 1 has been completed by automatically attaching a cap 20 to a spout 11 comprising a linking portion 12, an electrical current is made to flow to an internal coil in a state in which an electromagnetic induction heating device 30 is placed in contact from an upper surface of the cap 20 or in a state of non- contact so that heat is generated by an aluminium foil layer by means of electromagnetic induction, and a plastic underlayer and an annular portion 16 on the very top of the linking portion 12 are welded. In the following stage, after a predetermined short time, a temperature distribution on the surface of the cap 20 is acquired as an infrared thermal image using a commercially-available infrared camera, and this thermal image is displayed on a display with the temperature distribution being shown in predetermined colours by means of an image processing device. When colour is applied to the image, temperature ranges are divided into at least three stages, namely an optimum temperature range, a temperature range higher than the optimum temperature range, and a temperature range lower than the optimum temperature range. As will be described later, the optimum temperature range is a temperature range in which sufficient welding strength can be achieved, and other ranges are temperature ranges in which only insufficient welding strength can be achieved.

[0021]

Fig. 6 schematically shows patterns of temperature distributions on the surface of the cap 20 imaged in this way. Differences in temperature are not represented by colours in fig. 6, rather by differences in shading of cross-hatching. The dotted lines show the outer circumference of the cap 20 and locations corresponding to leg portions 15. [0022]

As shown in fig. 6(A)-(E), regions corresponding to the annular portion 16 had a higher temperature than a surrounding region, and a ring-shaped high-temperature region could be seen to reflect this. Non-uniformity was apparent in the temperature of the annular portion when a laminate 19 was cracked, when foreign material was pinched between the laminate 19 and the cap 20, or when the positions of the laminate 19 and the cap 20 were misaligned, etc. However, it was understood that even if the temperature in the region of the annular portion 16 was virtually uniform, there might still be variations in the actual temperature, as shown in (A)-(E). This is believed to be due to differences in adhesion between the aluminium foil/plastic laminate 19 and the cap 20, or the strength with which the cap 20 is fastened to the spout 11. Furthermore, the portion within the region of the annular portion 16 corresponding to locations in which the leg portions 15 were present tended to have a lower temperature than other portions of the ring shape. This is due to the fact that heat escapes more readily than in other regions because the leg portions 15 are present.

[0023]

According to the present invention, measurements were taken of temperature distribution patterns and temperatures therein of the abovementioned ring portion in a large number of conforming samples in which an inner cover 14 is also released from a packaging container 10 at the same time as the cap 20 is opened, i.e., conforming samples having sufficient welding strength, and the relationship between that data and the welding strength was investigated. According to the results obtained, sufficient welding strength was achieved in the case of fig. 6(A), fig. 6(B) and fig. 6(C), whereas the welding strength was insufficient in the case of fig. 6(D) and fig. 6(E). That is to say, however uniform the temperature of the ring portion, the welding strength was insufficient when the temperature in the leg portion regions was not within the abovementioned optimum temperature range, as in fig. 6(D) and fig. 6(E). In contrast to this, when the temperature of the leg portion regions was within the optimum temperature range, as in fig. 6(A), fig. 6(B) and fig. 6(C), sufficient welding strength was achieved even if the temperature in other regions of the ring portion was outside the optimum temperature range or there was non-uniformity in the temperature. Accordingly, in the inspection method according to the present invention, it is determined whether the temperature in two narrow regions (the regions enclosed by the dotted lines positioned at the top and bottom of the ring portions in fig. 6(A)-(E)) corresponding to the plurality of (two in this exemplary embodiment) leg portions 15 contained in a region corresponding to the annular portion 16, rather than the overall temperature of that region, is within the optimum temperature range. The temperature range in which sufficient welding strength is achieved which was obtained on the basis of the abovementioned experiment is the optimum temperature range, and this is pre-stored in a memory unit in the image processing device as a predetermined temperature range, and a determination may be made during the inspection by comparing the temperatures in the leg portion regions with the predetermined temperature range, without the need to make a determination by comparing the temperature distribution pattern of the whole of the ring portion with a pre-stored reference pattern.

[0024]

As one example of the present invention, the optimum temperature range obtained by actual measurement was 55-60 (°C). “Optimum temperature” represents this region in the exemplary shading shown on the bottom right of fig. 6, “> Optimum temperature” denotes a temperature range of 55 (°C) or greater, and “< Optimum temperature” denotes a temperature range of 60 (°C) or less. Moreover, the surface temperature of the cap 20 decreases together with elapsed time Tm after welding, so the optimum temperature range is necessarily dependent on Tm. Tm at the time of sample measurement therefore needs to be the same as Tm from after welding until measurement in the actual process. In this exemplary embodiment, the measurement was made at Tm=2 seconds. Furthermore, the optimum temperature range depends on the material and size, etc. of the unsealing device. The determination of conformity or non-conformity of the unsealing device will be described in greater detail here. In the case of fig. 6(A), the narrow regions in two locations corresponding to the leg portions 15 are within the optimum temperature range, so the welding strength is deemed to be sufficient, in other words the unsealing device is deemed to be conforming. Moreover, in the case of fig. 6(A), the other portions of the ring are within the optimum temperature range. In the case of fig. 6(B), the narrow regions in two locations corresponding to the leg portions 15 are within the optimum temperature range, and although the other portions of the ring have a temperature distribution beyond the optimum temperature, the welding strength is deemed to be sufficient, as mentioned above, in other words the unsealing device is deemed to be conforming. In the case of fig. 6(C), the narrow regions in two locations corresponding to the leg portions 15 are within the optimum temperature range, and the other portions of the ring have a temperature distribution below the optimum temperature, but the welding strength is deemed to be sufficient, as mentioned above, in other words the unsealing device is deemed to be conforming. Furthermore, the welding strength is deemed to be insufficient, in other words the unsealing device is deemed to be non- conforming when the regions in two locations corresponding to the leg portions 15 are beyond the optimum temperature or below the optimum temperature, even if the other portions of the ring are within the optimum temperature range, although this is not depicted.

[0025]

The inspection device for inspecting the strength of welding to the cap 20 of the unsealing device 1 in which the inner cover 14 is welded to the cap 20 via the linking portion 12 comprises: the infrared camera (not depicted) for acquiring, as two- dimensional distribution data, the wavelength and intensity of infrared radiation emitted from the surface of the cap 20; and the image processing device (not depicted) for imaging the temperature distribution on the surface of the cap from the two-dimensional wavelength distribution data. Commercially-available devices may be used for the infrared camera and the image processing device. Furthermore, in the inspection according to the present invention, it is necessary to identify the positions of the leg portions 15 which join the inner cover 14 and the cap 20 in the image of the surface of the cap, but in production processes in which the positions of the leg portions 15 vary on each container, it is necessary to use an optical means or the like, for example, to detect in advance the positions of the leg portions before the cap 20 is closed, and to supply the detected positions as auxiliary data to the image processing device. Such a position detection means is not required when the orientation of the unsealing device 1 attached is constant in the production process and the positions of the leg portions 15 are fixed. [Exemplary Embodiment 2]

[0026]

Instead of using the infrared camera to measure the temperature distribution on the surface of the cap from the two-dimensional wavelength data so as to determine the temperatures at the positions of the leg portions 15, it is equally possible to measure a plurality of temperatures at the positions of the leg portions using an infrared radiation thermometer capable of measuring the temperature in a narrow circular region, and to determine the conformity or non-conformity of the welding strength according to whether all of those temperatures are within the predetermined temperature range. The positions of the leg portions 15 are preferably constant in individual containers in this method. When the plurality of leg portions 15 are measured at the same time, a plurality of infrared radiation thermometers should be prepared correspondingly with the number of leg portions 15.

[0027]

The present invention was described above with reference to exemplary embodiments, but the present invention is not limited to the abovementioned mode of embodiment. Various improvements or design modifications may be made to the present invention within a scope that does not depart from the essential point of the present invention based on the knowledge of a person skilled in the art, and the present invention also includes any of the various improvements or design modifications.

[0028]

Furthermore, the content disclosed in Patent Document 1 which is a patent application of the applicant of this case is cited herein in regard to general concepts outside the characterizing sections of the present invention.

[Key to Symbols]

[0029]

I Unsealing device

10 Packaging container

I I Spout

12 Linking portion

13 Annular groove

14 Inner cover

15 Leg portion

16 Annular portion

19 Aluminium foil/plastic laminate

20 Cap Helical projection Helical groove Unsealing indication ring Electromagnetic induction heating device