JP2015013441A - Laminate film and packaging container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate film that can be employed to a packaging container, capable of preventing burst in heating at a microwave oven while allowing steaming.SOLUTION: A laminate film 10 includes a heat-fusible internal layer 30 made of a linear low density polyethylene resin, and an external layer 20 laminated on the internal layer. The laminate film 10 further includes a fragile processing part 40 formed by laser irradiation to the external layer 20, and having a depth that at least reaches inside the external layer 20 and does not penetrate the internal layer 30.

Description

  The present invention relates to a laminated film, and more particularly to a laminated film that can be suitably heated by a microwave oven when used in a packaging container, and a packaging bag using the laminated film.

  Conventionally, cooked or semi-cooked food is stored in a packaging container such as a packaging bag so that it can be stored at room temperature, low temperature, or frozen, and heated in a microwave oven without opening to make it ready for eating. ing.

  When the packaging container is heated without being opened, the moisture in the packaging container becomes water vapor and the volume increases. Therefore, if there is no gap through which water vapor can escape, there is a risk of bursting. On the other hand, when the contents are in a semi-cooked state, etc., not only heating but steaming with the generated water vapor may be required. In this case, if the hole through which the steam escapes is excessively large, there is a problem that the steaming is not sufficiently performed and the flavor is lowered.

  Several packaging bags for the above applications are known. In any case, it is generally formed using a laminated film. When the internal pressure is increased, a tear is formed in a part of the laminated film and water vapor is released from the tear, thereby preventing the explosion.

  As a packaging bag that can be steamed when heated by a microwave oven, for example, the one described in Patent Document 1 is known. In this packaging bag, a slit penetrating the outer layer and the inner layer is formed in a part of the laminated film having the outer layer and the inner layer, and then the inner layer is heated and melted, and only the inner layer is closed. When this packaging bag is heated in a microwave oven, the inner layer tears and small holes are formed. Therefore, steam does not escape excessively, and steaming can be performed while preventing bursting.

International Publication No. 2012/086295

  However, although the packaging bag described in Patent Document 1 can be steamed while preventing rupture, the process related to the formation and re-welding of the slits is complicated, which makes the manufacturing process complicated and improves the manufacturing efficiency. There is a problem that it is difficult. There is also a problem that it is difficult to guarantee the sealing quality after re-welding.

This invention is made | formed in view of the said situation, and it aims at providing the laminated film which can be steamed, applying a packaging container, preventing a burst at the time of the heating by a microwave oven.
Another object of the present invention is to provide a packaging container that can be steamed while preventing bursting when heated by a microwave oven.

  A first aspect of the present invention is a laminated film made of a linear low density polyethylene resin, comprising a heat-sealable inner layer and an outer layer laminated on the inner layer, and formed by laser irradiation on the outer layer And a fragile processed portion having a depth that reaches at least the inside of the outer layer and does not penetrate the inner layer.

  The impact fracture mass of the inner layer may be 100 grams or more and 800 grams or less.

The laminated film of the present invention may further include an intermediate layer provided between the inner layer and the outer layer.
At this time, the intermediate layer may be an ink layer that reduces the laminate strength between the inner layer and the outer layer, and may be formed in a region excluding the weakened portion and its periphery in plan view, or the intermediate layer may be the inner layer And a coating layer that improves the laminate strength between the outer layer and the outer layer, and may be formed in a region including both longitudinal sides of the fragile portion in plan view.

  According to a second aspect of the present invention, there is provided a packaging container characterized in that the laminated film of the present invention is provided at least in part, and a plurality of small holes are formed in the fragile processed portion when heated by a microwave oven.

According to the laminated film of the present invention, when applied to a packaging container, it can be steamed while preventing bursting when heated by a microwave oven, and can be easily manufactured.
Further, according to the packaging container of the present invention, steaming can be performed while preventing bursting during heating by a microwave oven, and manufacturing can also be easily performed.

It is a perspective view which shows the packaging bag formed with the laminated | multilayer film of 1st embodiment of this invention. It is sectional drawing in the AA of FIG. It is a figure which shows a weak processing part when heated with a microwave oven. (A) And (b) is sectional drawing in the modification of the laminated | multilayer film, respectively. (A) It is a fragmentary top view of the laminated film which concerns on 2nd embodiment of this invention, (b) is sectional drawing in the BB line of (a). (A)-(c) is a top view which shows the inner layer in the modification of the laminated | multilayer film, respectively. (A)-(f) is a top view which shows the weak processing part in the Example of the laminated | multilayer film of this invention. It is a perspective view which shows the modification of the packaging container of this invention.

A first embodiment of the present invention will be described with reference to FIGS. 1 to 4B.
FIG. 1 is a perspective view showing a packaging bag (packaging container) 1 of the present embodiment. The packaging bag 1 is formed in a bag shape by using the laminated film 10 of the present invention on which at least one surface can be heat-sealed. The packaging bag 1 according to the present embodiment has both ends in a direction in which the tubular lumen extends after the end 10a and the end 10b of the single laminated film 10 are heat-sealed into a substantially cylindrical shape. It is formed in a bag shape by joining 10c and 10d by thermal fusion.
In the packaging bag of this invention, there is no restriction | limiting in particular in the procedure and method of forming a laminated film in a bag shape. For example, a packaging bag may be formed by arranging two laminated films so as to face each other and joining the peripheral portions by heat fusion, or other methods may be used.

  FIG. 2 is a cross-sectional view of the laminated film 10 taken along the line AA in FIG. The laminated film 10 is configured by laminating an outer layer 20 that forms the outer surface of the packaging bag 1 and an inner layer 30 that forms the inner surface of the packaging bag 1 and can be heat-sealed. Both the outer layer 20 and the inner layer 30 are made of resin.

  The resin for forming the outer layer 20 is preferably a resin having relatively high rigidity from the viewpoint of protecting the contents, for example, polyethylene terephthalate (PET), biaxially oriented polypropylene (OPP), biaxially oriented nylon (ONy), etc. But not limited to these. The outer layer 20 may be subjected to secondary processing such as printing or vapor deposition to enhance designability or display various information. Such secondary processing may be performed on any surface of the outer layer 20.

  The inner layer 30 functions as a so-called sealant layer. As the resin forming the inner layer 30, linear low density polyethylene (LLDPE), which is a heat-sealable thermoplastic resin, is used. The impact fracture mass of the inner layer 30 is preferably 100 g (g) or more and 800 g or less, and more preferably 100 g or more and 700 g or less. In the present invention, the impact fracture mass is defined as a value measured according to JIS K7124 “Plastic film and sheet—impact test method by free-fall dart method”.

  The outer layer 20 and the inner layer 30 are bonded together by performing a known dry lamination process with an adhesive layer (not shown) interposed therebetween. The method for laminating the outer layer and the inner layer is not particularly limited, and may be sandwich lamination or coextrusion with another resin as described later.

  As shown in FIGS. 1 and 2, a weakened portion 40 from which at least a part of the outer layer 20 is removed is provided on a part of the outer surface of the packaging bag 1. The outer layer 20 of the fragile machined portion 40 is removed, for example, in a region having a width w1 of about 150 micrometers (μm) and a length l1 of 40 millimeters (mm), and a groove 40a is formed in the region. In the present embodiment, the fragile processed portion 40 is a portion of the laminated film 10 that is located in the groove 40 a and is thinner than other portions. In the fragile processed portion 40, almost all the outer layer 20 is removed.

There is no particular limitation on the degree of outer layer removal and the processing depth in the fragile processed part. For example, the inner layer may not be exposed due to the thin outer layer remaining over the entire surface of the fragile processed portion, or not only the outer layer but also a part of the inner layer may be removed. However, in order to prevent leakage of the contents before heating by the microwave oven, the fragile processed portion is formed so as not to penetrate the inner layer.
Further, the position where the fragile processed portion 40 is formed may be anywhere as long as it avoids the portions 10a to 10d and the like that are heat-sealed to form the laminated film 10 in a bag shape. It can be formed at an arbitrary position in consideration of the process and the like.

  As a means for forming the fragile processed portion 40, laser processing by laser irradiation is suitable. When laser processing is used, the shape and processing depth of the fragile processed portion can be adjusted relatively easily by adjusting the output of the laser head and the scanning speed. However, the forming means is not limited to laser processing, and other methods can be used.

  By forming the laminated film 10 in which the fragile processed portion 40 is formed at an arbitrary position in a substantially bag shape leaving the open end, and filling the contents from the open end, the open end is heat-sealed, The packaging bag 1 filled with the contents is completed. When the packaging bag 1 of the present embodiment filled with the contents is placed in a microwave oven and heated, the moisture contained in the contents expands as water vapor, and the internal pressure of the packaging bag 1 increases.

  As the internal pressure rises, a crack occurs in the fragile processed part, and a hole is formed through the laminated film in the thickness direction. However, the inventors of the present invention increase the internal pressure of the packaging bag 1 when heated by a microwave oven. It was discovered that the fragile processed portion 40 did not tear all over, and a plurality of small holes 41 separated from each other were formed as shown in FIG.

  This phenomenon is basically that the fragile processed portion 40 is easily deformed in the longitudinal direction of itself, but in the direction perpendicular to the longitudinal direction, it is close to the portion joined to the outer layer 20 and is not easily deformed. It is considered that the stress is concentrated at several points separated from each other in the processed portion 40. The reason why the rift does not spread so as to connect the formed small holes 41 is considered to be that the water vapor escapes from the small holes 41 and the internal pressure decreases.

The inventors have also found that when the fragile portion 40 is formed by laser processing, a large number of small holes 41 are formed at relatively short regular intervals along the longitudinal direction of the fragile portion 40. This is because a deep portion and a shallow portion are repeatedly formed in the groove formed when forming the fragile processed portion due to periodic fluctuations in the output of the laser beam, and the deeper portion of the groove, that is, the thinner portion in the fragile processed portion is earlier. This is presumably due to tearing and formation of small holes.
The LLDPE forming the inner layer 30 is flexible and easily stretched, and has high impact strength. Therefore, even after the small holes 41 are formed, the LLDPE can withstand the internal pressure acting on the laminated film, and the small holes communicate with each other and break. Is prevented.

  Since a plurality of small holes 41 are formed in the fragile processed portion 40, the water vapor generated inside the packaging bag 1 does not escape to the outside of the packaging bag 1 at a stretch, but escapes to the extent that it prevents bursting as the internal pressure increases. to continue. Thereby, steaming by the water vapor | steam which does not raise | generate a burst etc. also at the time of the heating with a microwave oven and remains in the packaging bag 1 is performed suitably.

  As described above, according to the packaging bag 1 provided with the laminated film 10 of the present embodiment, a plurality of small holes 41 are formed in the fragile processed portion 40 when heated by a microwave oven. The steaming can be suitably performed while keeping a part of the water vapor in the packaging bag.

  Further, in providing the fragile processed portion 40, a manufacturing process can be simplified because a process of separating the inner layer with a slit and then re-bonding is not necessary. Therefore, the packaging bag 1 can be manufactured easily.

  Further, the fragile processed portion 40 can be formed anywhere in the laminated film except for the end where the inner layers 30 are heat-sealed, and the degree of freedom in designing the packaging bag is high. Therefore, even when a plurality of types of packaging bags having different formation positions of the fragile processed portions according to the types of contents are manufactured, it can be easily handled by changing the laser irradiation position, for example.

  In the present embodiment, the outer layer and the inner layer are not necessarily a single layer. 4A, the outer layer 20A has a first layer 21 made of a first resin and a second layer 22 made of a second resin different from the first resin. doing. 4B, the inner layer 30A joined to the outer layer 20A includes an upper layer 31 made of LLDPE and a lower layer 32 made of LLDPE having physical properties different from those of the upper layer 31. . In the configuration as shown in FIG. 4B, the laminated film 10B can be formed without using an adhesive layer by bonding the outer layer 20A and the lower layer 32 with a third resin by a sandwich lamination method.

  A second embodiment of the present invention will be described with reference to FIGS. 5 (a) to 6 (c). The difference between the laminated film 51 of the present embodiment and the laminated film 10 forming the packaging bag 1 of the first embodiment is that an intermediate layer is provided between the outer layer and the inner layer. In the following description, components that are the same as those already described are assigned the same reference numerals and redundant description is omitted.

  Fig.5 (a) is a fragmentary top view of the laminated | multilayer film 51 of this embodiment, FIG.5 (b) is sectional drawing in the BB line of Fig.5 (a). As shown in FIG. 5B, in the laminated film 51, an ink layer (intermediate layer) 52 is formed between the outer layer 20 and the inner layer 30. The ink layer 52 is for improving the design of the packaging container or providing various displays related to products, and can be formed using various known inks.

  In general, the lamination strength between the outer layer 20 and the inner layer 30 decreases due to the presence of the ink layer 52. However, when the laminating strength of the fragile processed portion 40 and its periphery decreases, small holes may not be formed well during heating. Therefore, in this embodiment, as shown in FIG. 5A, such a situation is prevented by not forming the ink layer 52 around the fragile processed portion and the periphery thereof. The range in which the ink layer 52 is not formed around the fragile processed portion 40 can be appropriately set. For example, a rectangle including a position separated by 5 mm on both sides in the longitudinal direction and 2.5 mm on both sides in the width direction with the fragile processed portion 40 as the center. Range.

When the laminate strength between the outer layer and the inner layer is not originally high due to the compatibility of materials, the laminate strength may be improved by providing an intermediate layer. FIG. 6 shows such a modification.
FIG. 6A to FIG. 6C are partial plan views showing the laminated film in the modified example except for the outer layer. Of the inner layer 55, a strong laminate layer (intermediate layer) 56 is formed by applying medium on the surface to be joined to the outer layer. In the portion where the strong laminate layer 56 is formed, the outer layer and the inner layer are separated from each other. The laminate strength is improved over other parts. As shown in FIG. 6A, when the strong laminate layer 56 is formed on both sides in the longitudinal direction of the weakened portion 40 (the weakly processed portion is formed exclusively in the outer layer, and is indicated by a broken line), The action of stress in the fragile processed portion 40 becomes non-uniform, and a small hole 41 is formed in a portion P where the extension line of the fragile processed portion 40 and the strong laminate layer 56 intersect.

  Therefore, the strong laminate layer 56 in this modification may be formed at least on both sides in the longitudinal direction of the fragile processed portion 40, and as long as this condition is satisfied, as shown in FIG. It may be formed entirely, or as shown in FIG. 6C, it may be formed so as to cover all the longitudinal sides of the fragile portion. Although not shown, a strong laminate layer may be formed on the entire surface.

  Similarly to the laminated film 10 of the first embodiment, the laminated film 51 of the present embodiment is suitable for steaming while suitably preventing rupture due to an increase in internal pressure when heated by a microwave oven by being applied to a packaging container. Can be done.

  In addition, since there is an intermediate layer between the outer layer and the inner layer, the fragile processed part and the surrounding laminate strength are appropriately adjusted, so that even when more various materials are used as the outer layer and the inner layer, the fragile processed part is heated. A small hole can be suitably formed.

  Furthermore, if the intermediate layer is an ink layer, it is possible to easily impart designability to a packaging bag formed of a laminated film or display product information or the like.

Subsequently, the present invention will be further described using examples.
(Example 1 group)
The Example 1 group is an example in which the outer layer and the inner layer are each composed of a single layer.
In Examples 1-1 to 1-3, a PET film having a thickness of 12 μm was used as the outer layer, and LLDPE having a thickness of 30 μm or 40 μm was used as the inner layer. The outer layer and the inner layer are joined by dry lamination using an aliphatic ester-based dry laminating adhesive, and a fragile processed part having a width of 150 μm and a length of 40 mm and a depth substantially penetrating the outer layer is formed by laser irradiation. A laminated film was produced.
In Examples 1-4 to 1-6, PET having a thickness of 16 μm was used as the outer layer, and LLDPE having a thickness of 30 μm or 40 μm was used as the inner layer. Thereafter, bonding was performed in the same manner.
In Comparative Examples 1-A to 1-C, a PET film having a thickness of 12 μm was used as the outer layer, and low density polyethylene (LDPE) or unstretched polypropylene (CPP) (both had a thickness of 40 μm) was used as the inner layer.
The films of Examples and Comparative Examples were formed into a bag shape to form a packaging bag.

A heating experiment using a microwave oven was performed on the packaging bags of each Example and each Comparative Example according to the following procedure.
At the time of forming the packaging bag, 50 cc of water contained in a cloth and frozen was placed as a content in the packaging bag, and then the end was closed and sealed. The packaging bag containing the contents was heated for 2 minutes at an output of 600 watts using a microwave oven, and the presence or absence of rupture and the state of steaming were observed. The definition of rupture was defined as a state in which either a portion other than the fragile processed portion in the packaging bag was torn or a fragile processed portion was torn, but a rift extended to a portion other than the fragile processed portion. Regarding the steaming, the one in which the packaging bag was kept in the expanded state by water vapor during the heating was marked with ◯, and the others were marked with x. Table 1 shows the results of Examples 1-1 to 1-7 and Comparative Examples 1-A to 1-C.

As shown in Table 1, in the packaging bag of the example, the inner layer is easily stretched by using LLDPE for the inner layer, and a plurality of small holes are formed in the fragile processed portion formed by laser irradiation, and steam is generated without causing rupture. Escaped outside the packaging bag. Moreover, the expansion | swelling state of the packaging bag was hold | maintained and it was able to perform steaming suitably.
In contrast, in the comparative example, since the resin forming the inner layer is not LLDPE and the elongation rate is low, the entire fragile processed portion is greatly opened and steaming is insufficient, or on the extension line of the fragile processed portion or heat Rupture occurred at the end of the fused film.

(Example 2 group)
The example 2 group is an example in which at least one of the outer layer and the inner layer is composed of a plurality of layers.

(Example 2-1)
A PET film having a thickness of 12 μm and an ONy film having a thickness of 15 μm were used as the outer layer, and an LLDPE film having a thickness of 40 μm was used as the inner layer. The PET film and the ONy film, and the outer layer and the inner layer are joined by dry lamination using an aliphatic ester-based dry laminating adhesive, and by laser irradiation, the width is 150 μm, the length is 40 mm, and the depth of the outer layer is substantially penetrated. A fragile processed part was formed to produce a laminated film of Example 2-1.
The laminated film of Example 2-1 was formed into a bag shape by the same method as in Example 1-1 to obtain a packaging bag of this example.

(Example 2-2)
The configurations of the outer layer and the inner layer were the same as those in Example 2-1.
After the outer layer films were joined by dry lamination, sandwich lamination using LDPE as a sand layer was performed to join the outer layer and the inner layer. This produced the laminated film of Example 2-2 in which the outer layer and the inner layer were bonded via an adhesive layer (thickness 13 μm) made of LDPE. The laminated film of Example 2-2 was formed into a bag shape by the same method as in Example 1-1 to obtain a packaging bag of this example.

  Table 2 shows the results of a heating experiment using a microwave oven performed on the packaging bags of Examples 2-1 and 2-2 under the same conditions as in Example 1 group.

  As shown in Table 2, in Examples 2-1 and 2-2, a plurality of small holes were formed in the fragile processed part during heating, and steam was released outside the packaging bag without causing rupture. Moreover, the expansion | swelling state of the packaging bag was hold | maintained and it was able to perform steaming.

(Example 3 group)
Example 3 group is an example in which an ink layer for reducing the laminate strength is provided as an intermediate layer.
(Example 3-1)
A PET film having a thickness of 12 μm was used as the outer layer, and an LLDPE film having a thickness of 40 μm was used as the inner layer. An ink layer was formed on one surface of the PET film by printing with white ink, but spread in a width of 2.5 mm on all four sides of the linear fragile processed portion (the dimensions and the forming method are the same as in Example 1-1). An ink layer was not formed in the substantially band-shaped region. The laminated film of Example 3-1 is formed by joining the surface provided with the ink layer of the outer layer and the inner layer by dry lamination using an aliphatic ester-based dry laminate adhesive and forming a fragile processed portion by laser irradiation. Was made.
The laminated film of Example 3-1 was formed into a bag shape by the same method as in Example 1-1 to obtain a packaging bag of this example.

(Example 3-2)
Example 3-2 is different from Example 3-1 in that the LLDPE film having a thickness of 30 μm was used and the shape of the fragile processed portion in plan view. The fragile processed part was formed in a broken line shape by laser irradiation. The shape of the broken line was obtained by repeating a groove having a length of 1 mm 30 times with an interval of 0.1 mm.
(Examples 3-3 to 3-8)
Examples 3-3 to 3-8 differ from Example 3-1 only in the shape of the fragile machined portion in plan view. FIGS. 7A to 7F show the planar view shapes of the fragile portions in Examples 3-3 to 3-8, respectively.

(Example 3-9)
A laminated film and a packaging bag of Example 3-9 in the same procedure as Example 3-1, except that the ink layer was formed on the entire surface of the PET film (that is, there was no region where no ink layer was formed). Was made.

  Table 3 shows the results of a heating experiment using a microwave oven performed on the packaging bags of Examples 3-1 to 3-9 under the same conditions as in Example 1 group.

As shown in Table 3, in Examples 3-1 to 3-3 in which the ink layer was not formed around the fragile processed portion, a plurality of small holes were formed in the fragile processed portion during heating without causing rupture. Steam escaped outside the packaging bag. Moreover, the expansion | swelling state of the packaging bag was hold | maintained and it was able to perform steaming. Further, in Examples 3-2 to 3-8, the weakly processed portion has a characteristic shape that is not a mere straight line, so that a wound, a pinhole, or the like that is unintentionally formed in the manufacturing process of the packaging bag It became easier to distinguish.
On the other hand, in Example 3-9, steaming could be performed while suppressing rupture, but the number of small holes formed in the fragile processed portion was smaller than in other examples, and steam spouted from the packaging bag. The phenomenon was seen. Therefore, when providing an ink layer, it was shown that it is preferable to avoid the periphery of a weakly processed part.

(Example 4 group)
The Example 4 group is an example in which a strong laminate layer for increasing the laminate strength is provided as an intermediate layer.

(Example 4-1)
A PET film having a thickness of 12 μm was used as the outer layer, and an LLDPE film having a thickness of 40 μm was used as the inner layer. A 10 mm × 5 mm medium coat layer (strong laminate layer) was formed by printing on both sides in the longitudinal direction of the region where the fragile portion was formed. Of the outer layer, the surface on which the medium coat layer is provided and the inner layer are joined by dry lamination using an aliphatic ester-based dry laminating adhesive, and a depth of 150 μm in width and 40 mm in length that substantially penetrates the outer layer by laser irradiation. The fragile processed part was formed so as to be positioned between the two medium coat layers in plan view, thereby producing a laminated film of Example 4-1. In the laminated film of Example 4-1, the laminate strength between the outer layer and the inner layer in the media coat layer was 3 N / 15 mm.
The laminated film of Example 4-1 was formed into a bag shape by the same method as that of Example 1-1 to obtain a packaging bag of this example.

(Example 4-2)
Example 4-1 except that the medium coat layer was formed on the entire surface of the PET film except for the unformed region of 50 mm × 5 mm, and the fragile processed part was formed so as to be located in the unformed region in plan view. A laminated film and a packaging bag were produced in the same procedure as described above. The laminate strength of the outer layer and the inner layer in the medium coat layer was 3 N / 15 mm.

(Example 4-3)
Except for the point that the medium coat layer was formed on the entire surface of the PET film except for the unformed region having a length of 50 mm and extending in the width direction, and the fragile processed portion was formed so as to be located in the unformed region in plan view. A laminated film and a packaging bag were produced in the same procedure as in 4-1. The laminate strength of the outer layer and the inner layer in the medium coat layer was 3 N / 15 mm.

(Example 4-4)
A laminated film and a packaging bag were produced in the same procedure as in Example 4-1, except that the shape of the fragile processed part was the same as in Example 3-2. The laminate strength of the outer layer and the inner layer in the medium coat layer was 3 N / 15 mm.

  Table 4 shows the results of a heating experiment using a microwave oven performed on the packaging bags of Examples 4-1 to 4-4 under the same conditions as in Example 1 group.

  As shown in Table 4, in Examples 4-1 to 4-4 in which a medium coat layer was provided on both sides in the longitudinal direction of the fragile processed portion, an intersection (2 or more) between the extension line of the fragile processed portion and the medium coated layer during heating. A small hole was formed at the location, and the steam escaped outside the packaging bag without causing rupture. Moreover, the expansion | swelling state of the packaging bag was hold | maintained and it was able to perform steaming.

  The embodiments and examples of the present invention have been described above. However, the technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made to each component without departing from the spirit of the present invention. It is possible to add, delete, or combine the configurations of the embodiments.

  For example, the laminated film of the present invention can be used for packaging containers other than packaging bags. FIG. 8 shows an example of a packaging container 101 in which the laminated film 10 is attached as a lid material to a container body 100 formed of paper or the like. Even if it does in this way, when the packaging container 101 is heated with a microwave oven, steaming can be performed while appropriately releasing steam from the fragile processing portion 40 to prevent bursting and the like.

  In addition, the laminated film of the present invention may be manufactured by a so-called roll-to-roll method while winding the fragile processed portion and forming it into the shape of an original fabric. At this time, the extending direction of the fragile processed portion may be parallel to the winding direction, but if formed so as to be oblique to the winding direction, the fragile processed portion does not exist continuously in the winding direction. Therefore, it can prevent suitably that an unevenness | corrugation arises in the original fabric which wound up the laminated | multilayer film. As a result, storage and transportation can be suitably performed.

  Furthermore, the mode of the fragile processing part can be variously changed in addition to the above. For example, the fragile processed portion may be formed without removing the outer layer by so-called half-cut processing using blade processing such as a rotary die cutter. Further, the shape is not limited to a line segment extending in one direction, and may be formed in a line shape having a bent or curved portion or a plurality of line segments connected.

1 Packaging bag (packaging container)
10, 51 Laminated film 20, 20A Outer layer 30, 30A, 55 Inner layer 40 Fragile processed part 52 Ink layer (intermediate layer)
56 Strong laminate layer (intermediate layer)
101 Packaging container

Claims (6)

A laminated film comprising a linear low density polyethylene resin, comprising an inner layer that can be heat-sealed, and an outer layer laminated on the inner layer,
A laminated film comprising a fragile processed portion formed by laser irradiation on the outer layer, reaching at least the inside of the outer layer, and having a depth that does not penetrate the inner layer.   The laminated film according to claim 1, wherein the inner layer has an impact fracture mass of 100 g or more and 800 g or less.   The laminated film according to claim 1 or 2, further comprising an intermediate layer provided between the inner layer and the outer layer.   The said intermediate | middle layer is an ink layer which reduces the lamination strength of the said inner layer and the said outer layer, and is formed in the area | region except the said weakly processed part and its periphery in planar view.   The laminate according to claim 3, wherein the intermediate layer is a strong laminate layer that improves the laminate strength between the inner layer and the outer layer, and is formed in a region including both longitudinal sides of the fragile processed portion in plan view. the film.   A packaging container comprising at least a part of the laminated film according to any one of claims 1 to 5, wherein a plurality of small holes are formed in the fragile processed portion when heated by a microwave oven.

Images