JP2009236505A - Method for inspecting faulty sealing in container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for inspecting a leak caused by faulty sealing in a container hermetically sealed by a face-bonding sealing part, by which total inspection can be performed without destroying containers by inspection, or in a nondestructive manner. <P>SOLUTION: Two lead wires 3, 4, which are nearly in parallel and do not cross each other, are formed in advance for the bonding part of the sealing part 2 made of non-conductive material. One ends of the two lead wires 3, 4 are exposed to outside the sealing part 2 as a pair of terminals 3a, 4a. As for a hermetically sealed container 1, then, an ammeter 5 is connected to the pair of terminals 3a, 4a exposed to outside the sealing part 2 to inspect the presence or absence of a minute current, thereby inspecting the presence or absence of a leak in the sealing part 2 caused by faulty sealing. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a surface-sealed adhesive such as a heat-sealed portion for a container sealed with a surface-sealed seal portion such as a bag-like container or a cup-shaped container filled with contents such as food and sealed by heat-sealing. The present invention relates to a method for inspecting leakage due to a seal failure at a seal portion, and particularly to a method for inspecting a seal failure of a container capable of non-destructive and 100% inspection.

  In a bag-shaped container called a pouch or a cup-shaped container having a sheet-like lid, the container is sealed by heat sealing after filling the container with contents such as food. When heat-sealing in a container, the filling nozzle touches the heat-sealed part or the content splashes, and the content adheres to the heat-sealed part. There is a possibility that leakage of the contents may occur if the sealing causes a sealing failure or the contents enter the heat seal portion due to a sealing failure due to insufficient heating during heat sealing.

For inspection of the presence or absence of leakage due to poor sealing at the heat seal part in such a bag-like container or cup-like container, the packaging bag filled with the contents is pressed on the following Patent Document 1 to seal the packaging bag By adsorbing the liquid that has oozed from the parts and pinholes to the liquid absorbent sheet, and interposing the contact part of the liquid absorbent sheet with the packaging bag between the electrodes, A technique relating to a bag-like container for inspecting leakage is disclosed, and Patent Document 2 listed below uses a pinhole inspection machine to sandwich the upper surface of the lid and the lower surface of the flange portion of the container with an electrode, so that a high voltage A technology related to a cup-shaped container is disclosed in which the presence or absence of a flashing current due to a seal failure is detected by applying a mist.
JP-A-9-126939 JP 2002-39907 A

  By the way, according to the conventionally known method for inspecting a seal of a container as described above, in the technique described in the above cited document 1, by pressing the container, the technique described in the above cited document 2 is used. Then, since there is a possibility that the container may be destroyed in any case by applying a high voltage, there is a problem that it can only be applied as a sampling inspection and cannot be applied as a 100% inspection.

  An object of the present invention is to solve the above-described problems. Specifically, a method for inspecting leakage due to a sealing failure in a container sealed with a seal portion by surface bonding is performed by inspection. It is an object of the present invention to enable non-destructive inspection of all the containers without destroying the containers.

  In order to solve the above-described problems, the present invention provides a seal portion made of a non-conductive material in advance as a method for inspecting leakage due to a seal failure in a container sealed with a seal portion by surface bonding. Two conductive wire portions that are substantially parallel and do not intersect with each other are formed, and one end side of each of the two conductive wire portions is exposed to the outside of the seal portion as a pair of terminals. After that, the sealed container is connected to a pair of terminals exposed to the outside of the seal part, and an ammeter is connected to inspect for the presence of minute currents. It is characterized by inspecting.

According to the container sealing failure inspection method of the present invention as described above, there is no possibility of destroying the container by connecting an ammeter to the pair of terminals of the conductive wire portion and inspecting for the presence of a minute current. In the absence, it is possible to inspect the presence or absence of leakage due to a seal failure at the seal portion.
That is, when the liquid of the contents such as food is present in the seal portion due to the seal failure, a circuit is formed by shorting the two conductive wire portions, and an electrolyte substance such as a metal atom in the liquid of the content is formed. Since a current of about a small nanoampere flows due to ionization, it is possible to detect the presence or absence of leakage due to a seal failure by detecting the presence or absence of this minute current with an ammeter.

  When carrying out the method of the present invention as described above, the conductive line portion is formed by printing a conductive paint, and the surface on which the conductive line portion is printed is surface-bonded as a seal portion. It is preferable that one end side of the conductive wire portion is exposed to the outside of the seal portion as a pair of terminals by extending the portion further outward than the portion. A pair of terminals can be formed very easily.

  The best method for inspecting leaks due to defective seals in containers sealed with seals by surface bonding is to ensure that all inspections can be performed in a non-destructive manner without destroying the containers. As specifically shown in the following embodiments as a form, two conductive wire portions that are substantially parallel and do not intersect with the bonded portion of the seal portion made of a non-conductive material are formed in advance. Then, one end side of each of the two conductive wire portions is exposed to the outside of the seal portion as a pair of terminals, and then the pair of terminals exposed to the outside of the seal portion with respect to the sealed container This was achieved by connecting the ammeter and inspecting for the presence of a minute current, thereby inspecting for the presence of leakage due to a seal failure at the seal.

  In addition, for a container to which the method of the present invention is applied, that is, a container sealed with a seal portion by surface bonding, for example, a bag-like container called a pouch or a cup-like container having a sheet-like lid In these containers, the contents such as food are filled in the containers and sealed by heat sealing. Each Example about such a bag-shaped container and a cup-shaped container is demonstrated below.

  The method of the present embodiment relates to a bag-like container called a pouch, and can be heat-sealed on a single-layer film made of a thermoplastic synthetic resin capable of heat-sealing, or at least on the inner surface side (adhesion surface side). A multilayer film provided with a thermoplastic synthetic resin layer is used as a raw material, and a container manufactured in the form of a bag from the single thin film sheet is the object of inspection.

  When manufacturing a bag-like container to be inspected by the method of this embodiment, as shown in FIG. 2, the center of one elongate film sheet 10 is folded into a mountain shape, and the front wall continues before and after the folded portion 11. 13 and the back wall 14 are encased and overlapped so as to sandwich the chevron of the folding part 11, and both sides of the front wall 13 and the back wall 14 and the folding part 11 are sandwiched between heat sealing molds. It is sealed.

  A semi-circular cutout portion 12 is formed at substantially the center of both sides of the mountain-shaped folding portion 11, and the front wall 13 and the back wall 14 are enclosed so as to sandwich the folding portion 11. By heat-sealing as described above in the overlapped state, the front wall 13 and the folded portion 11 are heat-sealed, the back wall 14 and the folded portion 11 are heat-sealed, and the front wall 13 and the back wall 14 are further sealed. The bottom portion of the bag-like container is formed by heat sealing at the cutout portion 12.

  By the way, although it is not illustrated with respect to the container formed in the bag shape by joining the both sides of the front wall 13 and the back wall 14 as mentioned above, on the opposite side to the bottom, After the contents are filled from the opened opening, the bag-like container is sealed by heat-sealing the openings (the upper ends of the front wall 13 and the back wall 14). When the filling nozzle touches the opening of the container or the contents bounce and the contents adhere to the inside of the opening, the opening is heat sealed and the container is sealed. When the contents are caught in the heat seal portion, there is a possibility that a sealing failure may occur and leakage may occur.

  In order to inspect the presence or absence of such a sealing failure, in the method of the present embodiment, as shown in FIG. 2, the heat seal of the opening is preliminarily applied to the film sheet 10 for forming the bag-like container. However, in this embodiment, the two conductive wire portions 3 that are substantially parallel and do not intersect with the inner surface of the upper end portion of the back wall 14, may be used. 1 and one end of each of the two conductive wire portions 3 and 4 is heat sealed as a pair of terminals 3a and 4a as shown in FIG. The part 2 is exposed to the outside.

  In the method of this embodiment, the two conductive wire portions 3 and 4 are formed by printing on the sheet surface with a conductive paint blended with metal powder that is harmless to the human body in the state of a film sheet. ing. About the space | interval of the two conductive wire parts 3 and 4, although depending on the width | variety of the heat seal part 2, and the state (viscosity etc.) of the content, about 2-3 mm is suitable, The width is desirably up to about 1 mm so as not to lower the sensitivity.

  Further, in order to expose one end side of the conductive wire portions 3 and 4 as a pair of terminals 3a and 4a to the outside of the heat seal portion 2, in the method of the present embodiment, one end of each of the conductive wire portions 3 and 4 is used. Are inclined so as to reach the corner of the film sheet, and the radius of curvature of the corner of the wall (back wall 14) on which the conductive wire portions 3 and 4 are printed is set to the wall (front surface) facing it. In the container 1 sealed by heat sealing by making the radius of curvature of the corners of the wall 13) smaller than the radius of curvature, the conductive wire portions 3 and 4 are printed on the side of the wall portion (back wall 14). An extended portion extending outward from the heat seal portion 2 is formed so that the ends of the conductive wire portions 3 and 4 are exposed as a pair of terminals 3a and 4a on the surface of the extended portion. I am doing so.

  And in the method of a present Example, as shown in FIG. 1, the two conductive wire parts 3 and 4 are formed in the heat seal part 2, The one end side of the heat seal part 2 is made into a pair of terminals 3a and 4a. An ammeter 5 is connected to a pair of terminals 3a and 4a exposed to the outside of the heat seal portion 2 with respect to the sealed container 1 exposed to the outside, and the presence or absence of a minute current is detected by the ammeter 5. By inspection, when a minute current is detected, it is determined that there is a seal failure, and when a minute current is not detected, it is determined that there is no seal failure.

  The method of the present embodiment relates to a cup-shaped container comprising a container body having a flange portion and a sheet-like lid, and the shape of the cup-shaped container is a round cup-shaped container. However, in any case, a container in which the lid body is heat-sealed and sealed on the flange portion of the container main body is the object of inspection.

  The container body of the cup-shaped container may be an injection molding method in which a molten synthetic resin is injected into a cup mold, or a sheet material (a single-layer sheet made of a thermoplastic synthetic resin that can be heat-sealed, A pneumatic molding method in which a sheet softened by heat is pressed against a cup mold with compressed air using a multilayer sheet with a thermoplastic synthetic resin layer that can be heat-sealed at least on the inner surface side (adhesive surface side). Alternatively, it is manufactured by an appropriate method such as a vacuum forming method in which a vacuum is applied between the softened sheet and the mold and the sheet is sucked into a cup-shaped mold.

  The sheet-like lid that is heat-sealed to the flange of the container body can be a single layer of thermoplastic synthetic resin that can be heat-sealed, or thermoplastic that can be heat-sealed at least on the inner surface side (adhesion surface side) This is a multilayer sheet material having a synthetic resin layer, and has the same shape as the outer edge shape of the flange portion, and is provided with a tab portion as a clue when the lid is peeled off from the flange portion.

  In the cup-shaped container to be inspected by the method of the present embodiment, as shown in FIG. 4, the barrel 22 rises from the outer edge of the bottom 21 of the container body 20, and is flanged outward from the upper end of the barrel 22 in the horizontal direction. The portion 23 extends, and a sheet-like lid 24 is bonded to the flange portion 23 of the container body 20 by heat sealing.

  By the way, in the cup-shaped container 1 as described above, after the container body 20 is filled with contents such as food, the lid body 24 is heat-sealed to the flange portion 23 of the container body 20, whereby the container 1 However, when filling the contents, if the filling nozzle touches the flange part 23 or the contents bounces and the contents adhere to the upper surface of the flange part 23, the flange part When the lid 24 is heat sealed to 23 and the container is sealed, the contents are bitten into the heat seal portion (bonded portion between the flange portion 23 and the lid 24), resulting in a seal failure and leakage. There is a risk of getting up.

  In order to inspect the presence or absence of such a sealing failure, in the method of the present embodiment, as shown in FIG. 3, the peripheral portion of the lid 24 (within the range of the width of the flange portion 23 to be heat-sealed). The two conductive wire portions 3 and 4 that are substantially parallel and do not intersect with each other are formed in advance, and one end side of each of the two conductive wire portions 3 and 4 extends to the tab portion 24a of the lid 24. Although not shown in the figure, in a state where the lid body 24 and the flange portion 23 are bonded by heat sealing, the heat sealing portion (bonded portion of the flange portion 23 and the lid body 24) is used as the pair of terminals 3a and 4a. ) To be exposed to the outside.

  And in the method of a present Example, the two conductive wire parts 3 and 4 are formed in the heat seal part (adhesion part of the flange part 23 and the cover body 24) in the state which carried out double wrapping, and the one end side is formed. The sealed cup-shaped container exposed to the outside of the heat seal portion as the pair of terminals 3a and 4a is exposed to the outside of the heat seal portion in the same manner as in the first embodiment (first embodiment). By connecting an ammeter to the pair of terminals 3a and 4a and inspecting the presence or absence of a minute current with this ammeter, if a minute current is detected, it is determined that there is a seal failure. If it is not detected, it is determined that there is no sealing failure.

  Even in the method of this embodiment, the two conductive wire portions 3 and 4 are printed with a conductive paint containing a metal powder that is harmless to the human body as in the case of the embodiment (Example 1). In this way, the periphery of the lid body 24 is formed so as to go around twice. In this way, the two conductive wire portions 3 and 4 are double-circulated, so that the detection portion can be set on the entire heat seal portion (bonded portion of the flange portion 23 and the lid body 24). When inspecting with an ammeter as described below, even a small biting of the contents can be detected.

  According to the container sealing failure inspection method according to each of the embodiments (Examples 1 and 2) as described above, in either case, the contents are bitten into the heat seal part or the heat seal is performed. In the case where the seal is defective due to insufficient heating at the time, and the contents enter the heat seal portion, the conductive wire portion 3 and the conductive wire portion 4 are short-circuited by the liquid of the content that has entered the heat seal portion. If a circuit is formed and the content liquid contains 0.1% sodium chloride, etc., the electrolyte sodium contained in the content liquid is ionized, resulting in a current of about a small nanoampere. Flows. The presence or absence of this minute current is detected by an ammeter to inspect the sealing failure. By doing so, it is possible to detect a bite of 10 μm or more and a gap into which the content has entered.

  On the other hand, a defect that does not come into contact with the other conductive wire portion 3 even if the contents that have entered the heat seal portion come into contact with one conductive wire portion 4 is a minor defect and causes leakage. However, in such a case, according to the method of each of the above embodiments, the conductive wire portion 3 and the conductive wire portion 4 are not short-circuited, and a circuit is formed. Therefore, such defects are not detected, and as a result, minor defects that are not substantially problematic can be overlooked, thereby improving the product yield.

  As mentioned above, although each Example of the seal | sticker defect inspection method of the container of this invention was demonstrated, this invention is not limited only to the specific method as shown in each said Example, For example, test | inspection As for the sealing part, the sealing part is not limited to heat sealing as long as it is a surface-sealing sealing part, and may be a sealing part adhered by an adhesive or the like. It is not limited to a cup-shaped container, and other containers may be used, and the conductive wire portion (and a pair of terminals on one end thereof) can be easily formed by printing with a conductive paint. It is possible, but not necessarily limited to such.

  Moreover, when forming a conductive wire part, in the Example (Example 1) of a bag-shaped container, it forms so that it may print in advance on the film sheet used as the material of a container, but it heat-seals in a bag making process. In the embodiment (Example 2) of the cup-shaped container, the conductive line portion is formed on the lid side, but the side of the flange portion of the container may be formed. The conductive wire portion may be formed in the case, and in that case, an extended portion may be provided outward from the flange portion, and a pair of terminals of the conductive wire portion may be formed in the extended portion. Needless to say, it can be changed as appropriate.

The front view which shows the state which connected the ammeter to a pair of terminal exposed outside from the sealing part of a bag-shaped container about one Example (Example 1) of the inspection method of this invention. The perspective view which shows the state when folding the one elongate film sheet into a bag shape about the bag-shaped container shown in FIG. The bottom view of the cover body which shows the state by which the conductive wire part and the terminal were formed in the cover body of a cup-shaped container about other Example (Example 2) of the inspection method of this invention. The partial cross section side view which shows the cross section of the half of the cup-shaped container sealed with the cover body shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Container 2 Heat seal part 3 Conductive wire part 3a Terminal 4 Conductive wire part 4a Terminal 5 Ammeter

Claims (2)

  As a method for inspecting leakage due to poor sealing in a container sealed with a surface-sealed seal part, in advance, two parts that are substantially parallel and do not intersect with the adhesive part of the seal part made of a non-conductive material. A conductive wire portion is formed, and one end side of each of the two conductive wire portions is exposed to the outside of the seal portion as a pair of terminals, and then the sealed portion is sealed against the sealed container. Sealing failure of a container characterized by connecting a current meter to a pair of externally exposed terminals and checking for the presence of leakage due to sealing failure at the seal part Inspection method.   The conductive line portion is formed by printing a conductive paint, and the surface on which the conductive line portion is printed is extended outward from the portion to be surface-bonded as a seal portion. 2. The container seal failure inspection method according to claim 1, wherein one end side is exposed to the outside of the seal portion as a pair of terminals.

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