JP5734827B2 - Method for inspecting sealing quality of laminated packaging materials including intermediate metal layers - Google Patents

Description

  The present invention relates to a method for inspecting a sealing failure of a packaging material having a laminated structure including an intermediate metal layer, and more particularly to a method for inspecting a sealing failure of a packaging material having a laminated structure including an aluminum layer as a metal layer.

  Packing materials with a laminated structure including an intermediate metal layer can be used for packaging bags, laminated tubes, or instant foods such as retort food, confectionery, instant ramen powder soup and ingredients, chemical products, etc. that require light shielding and airtightness. Often used for container lid sheets.

  The packaging material having a laminated structure including the metal layer has a problem in that a defective seal portion cannot be visually inspected because the metal layer does not transmit light. To deal with this problem, Patent Document 1 discloses, as a conventional example, (1) a sealed container sealed in a vacuum chamber, and the change in the vacuum pressure in the vacuum chamber as air escapes from the sealed container is measured. Method, (2) A method in which a fixed load is applied to the sealed container in the vacuum chamber, and the positional change of the lid or film is detected by a magnetic sensor, etc. (3) Film pinholes and scratches are imaged using an imaging device After listing the method of inspection by processing, etc., the ground electrode is brought into contact with the aluminum foil, while the detection electrode is in contact with or close to the surface of the sealed container, a voltage is applied to determine the seal portion depending on the presence or absence of the discharge current. It is proposed to detect defects.

  Patent Document 2 discloses a method for solving a problem in which a white hair remover cream is discolored when a hair remover cream is filled in a laminate tube containing an aluminum foil layer using an olefin resin as a sealant. Fill the surface active agent, immerse one electrode rod of the tester in the surface active agent in this state, pierce the laminated film containing aluminum layer with the needle connected to the other electrode rod, and measure the resistance with the tester Propose to do.

JP 2004-69458 A JP-A-6-148121

  In the factory management, when the production line is regularly inspected and the newly installed or repaired production facility is commissioned, it is inspected whether the sealed packaging material is properly sealed.

  An object of the present invention is to provide a method capable of visually inspecting the sealing quality of a packaging material having a laminated structure including an intermediate metal layer.

  It is a further object of the present invention to provide an inspection method that does not require a special inspection device when inspecting the quality of the sealing of a packaging material having a laminated structure including an intermediate metal layer.

  Regarding the seal of the packaging material having a laminated structure including the intermediate metal layer, the factor that hinders the visual inspection is the metal layer. If the metal layer is not present, the visual inspection of the seal portion is possible. The inventor of the present application has come up with the present invention by paying attention to this point. That is, a packaging material having a laminated structure including an intermediate metal layer is generally a relatively strong material against acids or bases accessed from the surface of the packaging material because the metal layer is sandwiched between upper and lower synthetic resin layers. be able to. However, when the packaging material is cut and the metal layer is exposed on the cut end face, the metal layer is easily subjected to acid or base attack. The inventor of the present application has devised the present invention by focusing on the end face of the packaging material and focusing on the fact that only the metal layer can be dissolved by attacking with the acid or base from the end face of the packaging material. When many packaging materials are observed from this point of view, the end of the seal portion is often constituted by a cut end. Even if the end of the seal portion is not constituted by a cut end, the metal layer can be easily exposed on the end surface of the seal portion by cutting the end of the seal portion with scissors or a knife.

According to the present invention, the above technical problem is
A method for inspecting the suitability of a sealed portion sealed by thermal welding of a laminated packaging material including an intermediate metal layer,
A seal part of a packaging material having a laminated structure including an intermediate metal layer, wherein the seal part with the metal layer exposed from an end face of the seal part is immersed in an acid solution or a base solution to dissolve the metal layer. This is achieved by providing a method for checking pass / fail.

  The present invention typically further includes the step of accessing the colored liquid to the seal portion in which the metal layer is dissolved. Sealing failure can be easily visually observed when the colored liquid enters the sealing failure location. Moreover, the state of a seal failure can be visually confirmed by the shape of the colored liquid that has entered the seal portion.

  A laminated packaging material including an intermediate metal layer typically includes an innermost sealant layer, an outer base material layer, and an intermediate metal layer. Aluminum can be cited as a typical metal constituting the metal layer. An aluminum layer is comprised with a vapor deposition film or aluminum foil.

  Examples will be described below.

First embodiment :
A packaging bag of snack food fried in oil was prepared, and this inner bag was immersed in a 6N (normality) aqueous solution of sodium hydroxide (NaOH) to observe changes over time. This packaging bag has a five-layer structure from the innermost layer to the outermost layer. The outermost layer is composed of biaxially oriented polypropylene (OPP), the second outer layer is composed of polyethylene (PE), the intermediate layer is composed of an aluminum foil layer, and the second inner layer is composed of polyethylene (PE), The innermost layer is made of a laminated sheet composed of unstretched polypropylene (CPP).

That is, the structure of the snack food packaging bag is as follows.
(1) Base material layer (outermost layer): biaxially oriented polypropylene (OPP) (thickness 20 μm);
(2) Second outer layer: polyethylene (PE) (thickness 13 μm);
(3) Intermediate metal layer: aluminum foil (thickness 6.5 μm);
(4) Second inner layer: polyethylene (PE) (thickness 13 μm);
(5) Sealant layer (innermost layer): unstretched polypropylene (CPP) (thickness 20 μm).

  The packaging bag is formed by folding the above-mentioned five-layered laminated sheet in two and then heat-sealing the two sides to form a bag with one end open. In the food production line, the snack food is added to the bag with one end open. And then heat-sealing the open ends to make a sealed food bag.

  When the packaging bag sealed with the heat welding machine (sealing device) of the food production line was immersed in 6N-sodium hydroxide aqueous solution and the change of the state was observed, it was as follows. After immersing the packaging bag in an aqueous sodium hydroxide solution, the aluminum layer disappeared from the three sides of the packaging bag, that is, the seal portion, and the seal portion became transparent when two days passed. The layer remained. When 5 days had passed after immersion in the hydrochloric acid solution, the presence of the aluminum layer could not be visually confirmed, and the packaging bag became transparent as a whole and the inside could be observed.

  By removing the aluminum layer from the seal side, the second outer layer located outside and the inner layer located inside are separated from each other. This biaxially stretched polypropylene of the outer layer is printed. However, by removing the aluminum layer, the outer layer is separated from the second inner layer (PE) rather than the aluminum layer. From this, it is possible to visually observe the heat-welded state of the sealant layer from the outside without being obstructed by the printed layer when the seal portion is visually observed. In this visual inspection, it is convenient that the defective portion of the seal portion is colored.

  Intentionally, a poorly sealed packaging bag is made, and this packaging bag is immersed in a 6N sodium hydroxide aqueous solution. This immersion may be at least only the seal portion that seals after the food is put out of the three seal sides. When the immersed seal part became transparent, the packaging bag was taken out from the aqueous sodium hydroxide solution, washed with water, and then the seal part was further immersed in a colored liquid. The red colored liquid penetrates into the seal part that is intentionally incompletely sealed, and the shape of the defective seal is clearly observed with the red colored liquid in the seal part with the defective seal. I was able to.

  The seal part is colored by removing the aluminum layer and then immersing the packaging bag in, for example, a red colored liquid, filling and sealing the colored liquid in advance, putting the colored liquid in the packaging bag from which the aluminum layer has been removed, and the object to be inspected. The colored liquid can enter the poorly sealed part in a short time by making the colored liquid easily accessible from the inside or outside of the sealed part, such as hanging the packaging bag with the sealed part down. .

Second embodiment :
The packaging bag of the first example was prepared, and this packaging bag was immersed in a 6N (normality) hydrochloric acid aqueous solution, and the change with time was observed.

  After 2 days have passed since the packaging bag was immersed in the hydrochloric acid aqueous solution, the aluminum layer disappeared from the three sides of the packaging bag, that is, the seal portion, and the seal portion became transparent. It remained. At the time when 5 days had passed after being immersed in the hydrochloric acid solution, the presence of the aluminum layer could not be visually confirmed, and the packaging bag became entirely transparent and the inside could be observed.

  As a comparative example, a synthetic rubber adhesive was applied to the ends of three seal sides of the same packaging bag, the three seal sides were sealed with a synthetic rubber adhesive, and then immersed in a 6N hydrochloric acid aqueous solution. This comparative example was under the same conditions as the above example except that a synthetic rubber adhesive was applied to the three seal sides. Almost no change was observed when 2 days had passed after the immersion. When 5 days have passed since the immersion, a part of the seal side and the aluminum vapor deposition layer in the central part disappeared, but the disappearance was partial.

  After filling the coloring liquid, a packaging bag with a poor seal was intentionally made and immersed in a 6N hydrochloric acid aqueous solution. When at least three seal sides became transparent, the inner bag was taken out of the hydrochloric acid aqueous solution and washed with water. Later, the seal portion was further immersed in the coloring liquid. The red colored liquid penetrates into the seal part that is intentionally incompletely sealed, and the shape of the defective seal is clearly observed with the red colored liquid in the seal part with the defective seal. I was able to.

  From this comparative example, it can be concluded that in the second embodiment, the aqueous hydrochloric acid solution entered the aluminum layer of the intermediate layer from the end face of the seal side and the aluminum was dissolved.

Third embodiment :
A powder stew packaging bag was prepared, and this packaging bag was immersed in a 6N (normality) aqueous sodium hydroxide solution to observe changes over time. This packaging bag has a four-layer structure from the innermost layer to the outermost layer. The outermost layer is made of nylon (NY), the next second outer layer is made of polyethylene (PE), the next third layer is made of aluminum layer, and the innermost layer is made of polyethylene (PE) It is made from laminated sheets.

That is, the structure of the powder stew packaging bag is as follows.
(1) Base material layer (outermost layer): Nylon (NY) (thickness 15 μm);
(2) Second outer layer: polyethylene (PE) (thickness 13 μm);
(3) Intermediate metal layer: aluminum foil (thickness 6.5 μm);
(4) Sealant layer (innermost layer): polyethylene (PE) (thickness 13 μm).

The packaging bag is formed by folding the above four-layered sheet in two and heat-sealing the two sides to open one end of the bag. In the food production line, a powder stew is applied to the open end of the bag. A sealed stewed powder stew is made by placing and then thermally welding the open ends.

  After being immersed in the sodium hydroxide aqueous solution, when two days passed, the aluminum layer disappeared from the packaging bag, and the packaging bag became entirely transparent so that the inside could be observed.

  As a comparative example, a synthetic rubber adhesive was applied to the seal ends of the three seal edges of the cut-off end of the powder stew packaging bag, and the three seal edges were sealed with the synthetic rubber adhesive. Later, it was immersed in a 6N aqueous solution of sodium hydroxide (NaOH). This comparative example was under the same conditions as the above example except that a synthetic rubber adhesive was applied to the three seal sides. No change was seen in the packaging bag even when 5 days had passed after soaking.

  A packaging bag for powder stew with an unsatisfactory seal is intentionally created, and the packaging bag sealed with 6N-sodium hydroxide aqueous solution is soaked. When at least three seal sides become transparent, the packaging bag is removed. After removing from the hydrochloric acid aqueous solution, rinsing with water and immersing in the red colored liquid for 1 hour, the red colored liquid entered the seal part that was intentionally incompletely sealed. It was possible to observe clearly.

Fourth embodiment :
A packaging bag of the same powder stew as in the third example was prepared, and this packaging bag was immersed in a 6N (normality) aqueous hydrochloric acid solution, and the change with time was observed.

  When two days had passed after immersion in the aqueous hydrochloric acid solution, the aluminum layer disappeared from the packaging bag, and a part of the packaging bag was whitened, but there was no hindrance to the observation of the seal portion.

  As a comparative example, a synthetic rubber adhesive was applied to the seal ends of the three seal edges of the cut-off end of the powder stew packaging bag, and the three seal edges were sealed with the synthetic rubber adhesive. Later, it was immersed in a 6N aqueous hydrochloric acid solution. This comparative example was under the same conditions as the third example except that a synthetic rubber adhesive was applied to the three seal sides. After immersion, the aluminum layer disappeared locally from the second day, and after five days, the aluminum layer disappeared, but the base material layer nylon (NY) was whitened because it was weak against acid.

  Create a packaging bag for powder stew that is intentionally poorly sealed, immerse the sealed packaging bag in 6N-hydrochloric acid aqueous solution, and take out the packaging bag from the aqueous hydrochloric acid solution when at least three seal sides become transparent After being washed with water and immersed in a red colored liquid for 1 hour, the red colored liquid penetrates into the seal part that was intentionally incompletely sealed, and the state of poor sealing is clearly observed from the shape of the colored liquid. I was able to.

Example 5 :
A packaging bag of instant noodle powder soup was prepared, and this packaging bag was immersed in a 6N (normality) aqueous hydrochloric acid solution, and the change over time was observed. This packaging bag has a four-layer structure from the innermost layer to the outermost layer. Laminated structure where the outermost layer is made of polyethylene terephthalate (PET), the next second outer layer is made of polyethylene (PE), the next intermediate layer is made of aluminum, and the innermost layer is made of polyethylene (PE) Made from sheets.

That is, the structure of the powder soup packaging bag is as follows.
(1) Base material layer (outermost layer): polyethylene terephthalate (PET) (thickness 12 μm);
(2) Second outer layer: polyethylene (PE) (thickness 13 μm);
(3) Intermediate metal layer: aluminum foil (thickness 6.5 μm);
(4) Sealant layer (innermost layer): polyethylene (PE) (thickness 13 μm).

  A packaging bag is formed by folding a sheet of the above four-layer structure into two, and heat-welding the two sides to form a bag with one end open. In a food production line, powder soup is placed in the bag with one end open. A powdered soup in a sealed bag is made by placing and then thermally welding the open ends.

  After being immersed in hydrochloric acid aqueous solution, when two days have passed, the aluminum layer disappears from the portion excluding the central portion of the packaging bag, and all of the three sealing pieces of the packaging bag are transparent and the seal portion can be observed. It became so.

  As a comparative example, a synthetic rubber adhesive was applied to the seal ends of the three seal sides of the cut-off end of the packaging bag for powder soup, and the three seal sides were sealed with a synthetic rubber adhesive. Later, it was immersed in a 6N aqueous hydrochloric acid solution. This comparative example was under the same conditions as the above example except that a synthetic rubber adhesive was applied to the three seal sides. No change was seen in the packaging bag even when 5 days had passed after soaking.

  Create a packaging bag for powder soup that is intentionally poorly sealed, immerse the sealed packaging bag in 6N-hydrochloric acid aqueous solution, and remove the packaging bag from the hydrochloric acid aqueous solution when at least three seal sides become transparent After being washed with water and immersed in red colored liquid for 1 hour, the red colored liquid entered the seal part that was intentionally incompletely sealed, and what kind of seal failure occurred at the seal part with the defective seal. It was possible to observe clearly with a red coloring liquid.

Example 6 :
A packaging bag of the same instant noodle powder soup as in Example 5 was prepared, and this packaging bag was immersed in a 6N (normality) aqueous solution of sodium hydroxide (NaOH), and the change over time was observed.

  After being immersed in the aqueous solution of sodium hydroxide, the aluminum layer disappears from the portion excluding the central portion of the packaging bag when two days have passed, and all of the three sealing pieces of the packaging bag are transparent and the sealing portion is It became possible to observe. At the time when 5 days had passed since the immersion, all of the aluminum layer disappeared from the packaging bag.

Seventh embodiment :
A packaging bag of molded snack food was prepared, and this packaging bag was immersed in a 6N (normality) aqueous hydrochloric acid solution, and the change over time was observed. This packaging bag has a five-layer structure from the outermost layer to the innermost layer.

  The laminated packaging material of this packaging bag has an outermost layer made of biaxially oriented polypropylene (OPP), a second outer layer made of polyethylene (PE), an intermediate layer made of an aluminum vapor deposition layer, and a second inner layer. Are made of polyethylene (PE), and the innermost layer is made of a laminated sheet made of unstretched polypropylene (CPP). In addition, the aluminum vapor deposition layer which is a metal layer is comprised with the film (VMPET) which vapor-deposited aluminum to polyethylene terephthalate.

That is, the structure of the packaging bag of molded snack food is as follows.
(1) Base material layer (outermost layer): biaxially oriented polypropylene (OPP) (thickness 20 μm);
(2) Second outer layer: polyethylene (PE) (thickness 13 μm);
(3) Intermediate metal layer: Aluminum vapor deposited film (VMPET) (thickness 12 μm);
(4) Second inner layer: polyethylene (PE) (thickness 13 μm);
(5) Sealant layer (innermost layer): unstretched polypropylene (CPP) (thickness 20 μm).

  The packaging bag is formed by folding both sides of the above-mentioned five-layered sheet and heat-welding each other at the center part on the back, and then heat-welding one end to form a snack food. After forming the packaging bag which accommodates, and putting the molded snack food from the open end of the packaging bag, the molded snack food containing the sealed bag is made by thermally welding the open end.

  After being immersed in hydrochloric acid aqueous solution, when two days have passed, the aluminum layer disappears from the portion excluding the central portion of the packaging bag, and all of the three sealing pieces of the packaging bag are transparent and the seal portion can be observed. It became so.

  A packaging bag for molded snack food with a poor seal is intentionally made, and the packaging bag is immersed in a 6N-hydrochloric acid solution under the same conditions as in the above example, and packaging is performed when at least three seal portions become transparent. After removing the bag from the aqueous hydrochloric acid solution, washing it with water and immersing it in the red colored liquid for 1 hour and observing the seal part, the red colored liquid entered the seal part that was intentionally incompletely sealed. It was possible to clearly observe the state of the sealing failure visually by the outline shape.

  The embodiment of the present invention has been described above. However, when the metal layer is not exposed from the end surface of the seal side, the metal layer is removed from the end surface of the seal side by cutting the edge of the seal side with a knife or scissors. After the pretreatment, the seal side may be immersed in a base or acid solution. Further, as can be easily understood by those skilled in the art from the above description, the present invention can be effectively applied to the inspection of a sealing failure of a packaging material having a laminated structure including a metal layer. The present invention can be applied to materials. Specifically, it is not limited to the above-described sealed bag, but may be in the form of a tube, or may be an instant food lid sheet that can be eaten simply by pouring hot water.

Claims (4)

A method for inspecting the suitability of a sealed portion sealed by thermal welding of a laminated packaging material including an intermediate metal layer,
A seal part of a packaging material having a laminated structure including an intermediate metal layer, wherein the seal part with the metal layer exposed from an end face of the seal part is immersed in an acid solution or a base solution to dissolve the metal layer. A method to check pass / fail.   The method for inspecting the quality of the sealing portion of the packaging material having a laminated structure including the intermediate metal layer according to claim 1, further comprising a step of allowing a colored liquid to access the sealing portion in which the metal layer is dissolved.   The laminated structure including the intermediate metal layer according to claim 1 or 2, wherein the packaging material includes an innermost sealant layer positioned inside the metal layer and a base material layer positioned outside the metal layer. To check the quality of the sealing part of the packaging material.   The method to test | inspect the quality of the seal | sticker part of the packaging material of the laminated structure containing the intermediate metal layer as described in any one of Claims 1-3 whose said packaging material is a bag for accommodating a foodstuff.