JP7377406B2 - laminated film - Google Patents

Description

The present invention relates to a laminated film used as a lid material for containers for foods, medicines, etc.

Packaging containers for foods such as liquid beverages, liquid foods, syrups, and liquid medicines, pharmaceuticals, etc. are known to consist of a container body with a flange and a sheet-like lid material that is joined to the top surface of the flange of the container body. It is being The lid material is usually a composite film consisting of an upper layer film with barrier properties and a lower layer film that seals the opening of the container containing the contents, and the lower layer film is connected to the upper layer film and the flange of the container body. Joined. When the upper film is bonded to the lower film, the lower film is closed by the upper film, so it does not come into contact with the outside air and maintains hygiene. When in use, the upper film is peeled off from the lower film, a tube such as a straw is passed through the surface of the lower layer, and the contents can be utilized through the tube.

Various types of laminated films are used as lids for packaging containers for packaging products such as foods and pharmaceuticals. The characteristics and functionality required for packaging containers include ``easy opening'' so that consumers can easily access the contents of the container during use, and ``easy to open'' so that consumers can easily access the contents inside the container. (after), it is desirable that the layer interface between the upper layer film and the lower layer film maintains hygiene, and that it is also provided with barrier properties to prevent the contents from deteriorating during distribution and storage. .

According to the invention proposed in Patent Document 1, the lid material is made of a composite film in which an upper layer (barrier layer)/separation layer/lower layer (ventilation layer) are laminated in order from the outside, The layer is composed of an easily peelable layer and an adhesive resin layer, and is devised so that the easily peelable layer cohesively peels off when peeled off.

However, with this mechanism, the easily peelable layer, the adhesive resin layer, and in some cases each layer migrates and both remain at the peeling interface after peeling. As a result, it is hygienically unsuitable for food and pharmaceutical applications when used through a peeling interface.

In addition, Patent Document 2 describes a lid material that can be sealed with a one-step seal with the flange portion of a packaging container and that can be separated into an upper layer and a lower layer, and that can be easily peeled off from the packaging container by peeling off the lid material from a pull tab. A lid material that can be separated into an upper layer and a lower layer has been proposed.
This lid material is a lid material made of a composite film in which an upper layer (base material), a separation layer, and a lower layer (ventilation layer) are sequentially laminated from the outside, and is characterized in that the separation layer is made of a single polymer alloy layer. It is a separable lid material.

However, in this lid material, a half-cut line that penetrates only the lower layer must be provided between the outer periphery of the seal and the outer periphery of the flange, which is a trigger for peeling, at the pull tab base that becomes the peeling boundary, and this process is troublesome. .

JP2003-237811A Japanese Patent Application Publication No. 2006-131233

The present invention has been made in view of the above circumstances, and is a laminated film used as a lid material for packaging containers for packaging products such as foods and pharmaceuticals, which comprises an upper layer film having barrier properties, and a material that protects the contents. This is a composite film consisting of a lower layer film that seals the opening of a container containing a product, and the upper layer film can be easily peeled off from the lower layer film during use, and the peeling interface can be kept sanitary. Take it as a challenge.

The invention according to claim 1 is a laminated film used for a lid material that covers the opening of a flanged molded container and is hermetically sealed with a flange portion at the periphery of the molded container, the lid material having two layers, an upper layer and a lower layer. The lower layer has a first layer and a polyethylene terephthalate layer, and the upper layer has an extruded ethylene-methacrylic acid copolymer film, at least a portion of which is bonded to the non-corona-treated surface of the polyethylene terephthalate layer. This is a laminated film including a combined layer and a second layer.

Next, the invention according to claim 2 is a laminated film used for a lid material that covers the opening of a flanged molded container and is hermetically sealed with a flange portion at the periphery of the molded container, the lid material comprising an upper layer and a lower layer. The lower layer has a first layer and an extruded ethylene/methacrylic acid copolymer layer, and the upper layer has at least a portion of the uncorona-treated surface made of the extruded ethylene/methacrylic acid copolymer. A laminated film comprising a polyethylene terephthalate layer bonded to a copolymer layer and a second layer.

Moreover, the invention according to claim 3 is the laminated film according to claim 1 or 2, which includes a peel initiation part where the polyethylene terephthalate layer and the extruded ethylene methacrylic acid copolymer layer are not joined.

Further, the invention according to claim 4 is the laminated film according to claim 3, wherein the peeling start part is such that one edge of the polyethylene terephthalate layer and the extruded ethylene methacrylic acid copolymer layer protrudes from the other edge. be.

The invention according to claim 5 is the laminated film according to any one of claims 1 to 4, wherein the first layer includes a sealant layer.

By using the laminated film of the present invention as a lid material for packaging containers for foods, medicines, etc., the upper layer can be easily peeled off from the lower layer during use, and the peeled interface can be kept sanitary.

FIG. 2 is a perspective view of a package using the lid material of the embodiment. FIG. 2 is a sectional view taken along the line X-X in FIG. 1. FIG. 3 is a cross-sectional view of the laminated film of FIG. 2 in the middle of delamination. FIG. 2 is a cross-sectional view of another type of laminated film taken along the line XX in FIG. 1. FIG. 3 is a cross-sectional view of the laminated film of FIG. 2 in a state in which delamination has been completed and the contents are in use. FIG. 3 is a diagram showing the layer structure of Example 1. FIG. 7 is a diagram showing the layer structure of Example 2. FIG. 3 is a diagram showing the layer structure of Comparative Example 1. FIG. 3 is a diagram showing the layer structure of Comparative Example 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of an embodiment of the present invention will be specifically described below based on the drawings. The package 1 shown in FIG. 1 includes a container 10 and a lid 20 that closes the opening 12 of the container 10, and the lid 20 is composed of the laminated film 30 of the present invention. The laminated film 30 consists of two laminated films, a lower layer film 40 and an upper layer film 50. The type of container 10 can be selected arbitrarily. In FIG. 1, the container 10 is a bottle, but it may also be a tray, a cup, or a bag. The contents 100 contained in the container 10 can be arbitrarily selected. Examples of contents 100 are medicines and foods. An example of a pharmaceutical product is powdered sodium. An example of a food product is yogurt. The state of the contents 100 contained in the container 10 is liquid or solid.

The material constituting the container 10 can be selected arbitrarily. In a preferred example, the container 10 is constructed of a material that can be easily heat-sealed with the first layer 41 of the lower film 40 that constitutes the laminated film 30. An example of a material constituting the container 10 is polyethylene. The container 10 includes a storage section 11 that accommodates the contents 100, and an opening 12 through which the contents 100 pass.

The lid 20 is joined to the top surface 12A of the opening 12 so as to close the opening 12. The connection form between the lid 20 and the container 10 can be selected from various forms. In the first example, the lid 20 and the container 10 are joined by heat sealing. In the second example, the lid 20 and the container 10 are joined by adhesion. In the third example, the lid 20 and the container 10 are joined by adhesive.

<Layer configuration of laminated film 30>
(Embodiment 1)
The lid 20 is composed of a laminated film 30. The laminated film 30 shown in FIG. 2 is a film in which a lower layer film 40 and an upper layer film 50 are joined by an extrusion lamination method. An example of an extrusion lamination method is a sandwich lamination method. The laminated film 30 is configured such that the upper film 50 can be easily peeled off (hereinafter referred to as "delamination") from the lower film 40. Further, when the laminated film 30 is delaminated, no adhesive or the like is present at the peeling interface 30A of the lower film 40. Therefore, the sanitary state of the contents 100 contained in the container 10 is maintained.

The lower film 40 has, for example, a three-layer structure in which a first layer 41, an intermediate layer 42, and a polyethylene terephthalate layer 43 are laminated. The first layer 41 is joined to the top surface 12A of the container 10. In one example, the first layer 41 is joined to the entire surface of the top surface 12A. The first layer 41 includes a sealant layer 41A.

The material constituting the sealant layer 41A can be arbitrarily selected. In a preferred example, the material that makes up the sealant layer 41A is the same material that makes up the container 10, or a material that can be heat-sealed to the container 10. Therefore, the first layer 41 can be easily heat-sealed to the container 10 or the like.

The intermediate layer 42 is laminated between the first layer 41 and the polyethylene terephthalate layer 43. The material constituting the intermediate layer 42 can be selected arbitrarily. In a preferred example, the intermediate layer 42 is constructed of a material that increases the strength of the first film 40 so that the underlying film 40 does not rupture when the laminated film 30 is delaminated. An example of a material constituting the intermediate layer 42 is biaxially oriented polypropylene.

The polyethylene terephthalate layer 43 is joined to the upper extruded ethylene/methacrylic acid copolymer layer 60 by an extrusion coat lamination method on the surface that has not been subjected to corona treatment. The polyethylene terephthalate layer may be corona-treated on only one side, or may be corona-treated on both sides. Corona treatment involves applying corona discharge to the surface of the film, which causes the main chains and side chains of polymer bonds on the film surface to be separated, and oxygen radicals, ozone, etc. in the discharge atmosphere to bond therewith, and to form hydroxyl groups (OH). Polar functional groups such as carbonyl and carbonyl groups (CO) are formed, imparting hydrophilicity. This improves wettability and improves printability and adhesive coating properties. Polyethylene terephthalate films sold for general laminating purposes are corona-treated, and corona-treated polyethylene terephthalate films have a surface wettability of about 50 to 60. The wettability of polyethylene terephthalate film without corona treatment is around 40. Further, if barrier properties are required, the intermediate layer 42 is made of a material having water vapor barrier properties or oxygen barrier properties. An example of a material having oxygen barrier properties or water vapor barrier properties is a transparent vapor-deposited film in which aluminum oxide or silicon dioxide is vapor-deposited.

The upper film 50 has, for example, a four-layer structure in which an extruded ethylene/methacrylic acid copolymer layer 60, a first intermediate layer 51, a second intermediate layer 52, and a second layer 53 are laminated. In addition, as another embodiment, a configuration that does not include the first intermediate layer 51 and the second intermediate layer 52 is also possible. The first intermediate layer 51 is laminated between the extruded ethylene/methacrylic acid copolymer layer 60 and the second intermediate layer 52 . The material constituting the first intermediate layer 51 can be selected arbitrarily. In a preferred example, the first intermediate layer 51 is made of polyethylene so that the second intermediate layer 52 and the extruded ethylene/methacrylic acid copolymer layer 60 are strongly bonded.

The second intermediate layer 52 is laminated between the first intermediate layer 51 and the second layer 53. The material constituting the second intermediate layer 52 can be selected arbitrarily. In a preferred example, the second intermediate layer 52 is made of a material that increases the strength of the upper layer film 50 so that the upper layer film 50 does not break when the laminated film 30 is delaminated. An example of a material constituting the second intermediate layer 52 is polyethylene terephthalate.

The material constituting the second layer 53 can be selected arbitrarily. In a preferred example, the second layer 53 is made of a material having oxygen barrier properties and water vapor barrier properties so as to protect the contents 100 contained in the container 10 during the distribution process of the package 1 . An example of a material having oxygen barrier properties or water vapor barrier properties is a transparent vapor-deposited film in which aluminum oxide or silicon dioxide is vapor-deposited.

FIG. 3 shows a cross-sectional view of a state where the polyethylene terephthalate layer 43 on the uppermost surface of the lower film and the extruded ethylene/methacrylic acid copolymer layer 60 on the lowermost surface of the upper film are delaminated at the interface.

(Embodiment 2)
In an embodiment, if the interface to be delaminated is the joint surface between the non-corona-treated surface of the polyethylene terephthalate layer 43 and the extruded ethylene/methacrylic acid copolymer layer 60, the layer remaining in the container 10 after delamination (hereinafter referred to as The peel-off remaining layer) may be either the polyethylene terephthalate layer 43 or the extruded ethylene/methacrylic acid copolymer layer 60. In the case of Embodiment 1, the extruded ethylene/methacrylic acid copolymer layer 60 is a peeling layer that is removed when the layers are peeled off, and the polyethylene terephthalate layer 43 is the peeling remaining layer.

As a second embodiment, it is also possible to configure the polyethylene terephthalate layer 43 to be a release layer and the extruded ethylene/methacrylic acid copolymer layer 60 to be a release layer. FIG. 4 shows the layer structure of Embodiment 2.

The laminated film 30 shown in FIG. 4 is a film in which a lower layer film 40 and an upper layer film 50 are joined by an extrusion lamination method. The lower film 40 has, for example, a three-layer structure in which a first layer 41, an intermediate layer 42, and an extruded ethylene/methacrylic acid copolymer layer 60 are laminated.

The first layer 41 includes a sealant layer 41A and is a material that can be heat-sealed to the container 10. The intermediate layer 42 is laminated between the first layer 41 and the extruded ethylene/methacrylic acid copolymer layer 60. An example of a material constituting the intermediate layer 42 is polyethylene terephthalate. The extruded ethylene/methacrylic acid copolymer layer 60 is bonded to the non-corona-treated surface of the polyethylene terephthalate layer by an extrusion coat lamination method.

Further, if barrier properties are required, the intermediate layer 42 is made of a material having water vapor barrier properties or oxygen barrier properties. An example of a material having oxygen barrier properties or water vapor barrier properties is a transparent vapor-deposited film in which aluminum oxide or silicon dioxide is vapor-deposited.

The upper film 50 has, for example, a four-layer structure in which a polyethylene terephthalate layer 43, a first intermediate layer 51, a second intermediate layer 52, and a second layer 53 are laminated. In addition, as another embodiment, a configuration that does not include the first intermediate layer 51 and the second intermediate layer 52 is also possible.

The first intermediate layer 51 is laminated between the polyethylene terephthalate layer 43 and the second intermediate layer 52. In a preferred example, the first intermediate layer 51 is made of polyethylene so that the second intermediate layer 52 and the polyethylene terephthalate layer 43 are strongly bonded.

The second intermediate layer 52 is laminated between the first intermediate layer 51 and the second layer 53. In a preferred example, the second intermediate layer 52 is made of a material that increases the strength of the upper layer film 50 so that the upper layer film 50 does not break when the laminated film 30 is delaminated. An example of a material constituting the second intermediate layer 52 is polyethylene terephthalate.

In a preferred example, the second layer 53 is made of a material having oxygen barrier properties and water vapor barrier properties so as to protect the contents 100 contained in the container 10 during the distribution process of the package 1 . An example of a material having oxygen barrier properties or water vapor barrier properties is a transparent vapor-deposited film in which aluminum oxide or silicon dioxide is vapor-deposited.

<Delamination strength>
The peel strength (hereinafter referred to as "interlayer peel strength") between the polyethylene terephthalate layer 43 and the extruded ethylene/methacrylic acid copolymer layer 60 is set so that the layer can be easily peeled off. Delamination strength is the peel strength measured by the T-peel strength test. The shape of the laminated film 30 used in the T-peel strength test is square. The length of one side of the laminated film 30 is 15 mm. The peeling speed is 300 mm/min. The peeling mode is a mode in which the upper layer film 50 is peeled from the lower layer film 40.

In a preferred example, the delamination strength is determined based on the relationship between the difficulty of delamination during the distribution stage of the package 1 and the ease of delamination during the use stage of the package 1. An example of the maximum value of the delamination strength is 2.0 N/15 mm. When the delamination strength is 2.0 N/15 mm or less, the user can easily delaminate the laminated film 30 when the package 1 is used. An example of the minimum value of the interlayer strength is 0.1 N/15 mm. When the delamination strength is 0.1 N/15 mm or more, unintended delamination is unlikely to occur even if an impact is applied to the package 1 during the distribution stage of the package 1. The preferred range of interlayer peel strength is 0.1 N/15 mm to 2.0 N/15 mm.

<Peeling start part>
As shown in FIG. 2, the laminated film 30 is provided with a peel initiation portion 30B where the polyethylene terephthalate layer 43 and the extruded ethylene/methacrylic acid copolymer layer 60 are not joined. Therefore, the work of peeling off the polyethylene terephthalate layer 43 and the extruded ethylene/methacrylic acid copolymer layer 60 can be easily carried out. In the peeling starting portion 30B, one edge of the polyethylene terephthalate layer 43 and the extruded ethylene/methacrylic acid copolymer layer 60 protrudes from the other edge. In the example shown in FIG. 2, in the peeling start portion 30B, the edge 60A of the extruded ethylene/methacrylic acid copolymer layer 60 protrudes from the edge 43A of the polyethylene terephthalate layer 43. In the example shown in FIG. 4, the edge 43A of the polyethylene terephthalate layer 43 protrudes from the edge 60A of the extruded ethylene/methacrylic acid copolymer layer 60 in the peeling start portion 30B. Since the peeling starting portion 30B is easy to grasp, the work of peeling off the polyethylene terephthalate layer 43 and the extruded ethylene/methacrylic acid copolymer layer 60 can be carried out even more easily.

An example of how to use the package 1 will be described with reference to FIGS. 3 and 5. The package 1 is distributed in a state in which the upper film 50 including the second layer 53 having barrier properties is joined to the lower film 40. At the stage of using the package 1, the user grasps the peeling start part 30B of the laminated film 30 and peels the extruded ethylene/methacrylic acid copolymer layer 60 from the lower film 40, as shown in FIG. After the delamination of the laminated film 30 is completed, as shown in FIG. 5, the user pierces the lower film 40 with a straw-shaped jig 70 for injecting dilution water. Since no adhesive or the like is present at the peeling interface 30A, foreign matter is less likely to enter the accommodating portion 11 when the jig 70 is passed through the lower film 40. By pouring dilution water into the container 11 via the jig 70, the sodium chloride agent, which is an example of the contents 100, is diluted.

According to Package 1, the following functions and effects can be obtained. When the non-corona-treated surface of the polyethylene terephthalate layer 43 and the extruded ethylene/methacrylic acid copolymer layer 60 are joined by extrusion coat laminate, the polyethylene terephthalate layer 43 and the extruded ethylene/methacrylic acid copolymer layer 60 are bonded together. It was confirmed that it could be easily peeled off.

The inventor of the present application conducted a test to confirm the relationship between the layer structure of the laminated film 30 and the interlayer peel strength using samples of Examples 1 and 2 and Comparative Examples 1 and 2. Table 1 shows the results of the test. In the following description, for convenience of explanation, the same reference numerals are given to parts of the sample of the comparative example that are common to the sample of the example. The sample of the example is a laminated film 30 having the layer structure of the embodiment. The sample of the comparative example is a laminated film 30 having a different layer structure from the laminated film 30 of the example.

<Example 1>
The layer structure of the laminated film 30 of Example 1 is shown in FIG. This is a film in which a lower layer film 40 and an upper layer film 50 are joined by an extrusion lamination method. The lower film 40 has a three-layer structure in which a first layer 41, an intermediate layer 42, and a polyethylene terephthalate layer 43 (PET) are laminated. The first layer 41 is a polyethylene layer (PE). The intermediate layer 42 is laminated between the first layer 41 and the polyethylene terephthalate layer 43. Intermediate layer 42 is biaxially oriented polypropylene (OPP). The non-corona-treated surface of the polyethylene terephthalate layer 43 is bonded to an extruded ethylene/methacrylic acid copolymer layer 60 (extruded EMAA) by an extrusion coat lamination method. The upper film 50 has a four-layer structure in which an extruded ethylene/methacrylic acid copolymer layer 60, a first intermediate layer 51, a second intermediate layer 52, and a second layer 53 are laminated. The first intermediate layer 51 is a polyethylene layer (PE). The second intermediate layer 52 is a polyethylene terephthalate layer (PET). The second layer 53 is a transparent vapor-deposited film in which aluminum oxide having oxygen barrier properties and water vapor barrier properties is vapor-deposited.

<Example 2>
The layer structure of the laminated film 30 of Example 2 is shown in FIG. The laminated film 30 of Example 2 is
This is a film in which a lower layer film 40 and an upper layer film 50 are joined by an extrusion lamination method. The lower film 40 has a three-layer structure in which a first layer 41, an intermediate layer 42, and an extruded ethylene/methacrylic acid copolymer layer 60 (extruded EMAA) are laminated. The first layer 41 is a polyethylene layer (PE). The intermediate layer 42 is laminated between the first layer 41 and the extruded ethylene/methacrylic acid copolymer layer 60. Intermediate layer 42 is a polyethylene terephthalate layer (PET). The extruded ethylene/methacrylic acid copolymer layer 60 is bonded to the non-corona-treated surface of the polyethylene terephthalate layer 43 by an extrusion coat lamination method. The upper film 50 is composed of two layers: a polyethylene terephthalate layer 43 (PET) and a second layer 53. The second layer 53 is a transparent vapor-deposited film on which aluminum oxide having oxygen barrier properties and water vapor barrier properties is vapor-deposited.

<Comparative example 1>
The layer structure of the laminated film 30 of Comparative Example 1 is shown in FIG. The laminated film 30 of Comparative Example 1 is bonded to the extruded ethylene/methacrylic acid copolymer layer 60 (extruded EMAA) on the corona-treated surface of the polyethylene terephthalate layer 43 of the lower film 40 by an extrusion coat lamination method. It differs from the laminated film 30 of Example 1 in this respect, and has the same configuration as the laminated film 30 of Example 1 in other respects.

<Comparative example 2>
The layer structure of the laminated film 30 of Comparative Example 2 is shown in FIG. The laminated film 30 of Comparative Example 2 differs from the laminated film 30 of Example 1 in that it includes an extruded polyethylene layer 60 (extruded PE) instead of the extruded ethylene/methacrylic acid copolymer layer 60, and is different from the laminated film 30 of Example 1 in that it includes an extruded polyethylene layer 60 (extruded PE) instead of the extruded ethylene/methacrylic acid copolymer layer 60. It has the same configuration as the laminated film 30 of Example 1.

Table 1 shows the measurement results of interlayer peel strength. To measure the interlayer peel strength, the laminated film 30 was cut to a width of 15 mm, peeled 90 degrees at a speed of 300 mm/min, and the peel strength was measured. Further, "○" in the item of measurement of interlayer peel strength in Table 1 indicates the case where the interlayer peel strength is within the range of 0.1 N/15 mm to 2.0 N/15 mm. "x" in the item of measurement of interlayer peel strength in FIG. 5 indicates a case where the interlayer peel strength is 0.1 N/15 mm or less or 2.0 N/15 mm or more. The item "before sealing" in Table 1 indicates the delamination strength of the laminated film 30 when the laminated film 30 is not bonded to the container 10. The item "after sealing" in Table 1 indicates the interlayer peel strength of the laminated film 30 when the first layer 41 of the laminated film 30 is joined to the container 10 by heat sealing. Heat sealing conditions include temperature, pressure, time, and number of times. The temperature condition is 190°C. The pressure condition is 0.4 MPa. The time condition is 2.5 seconds. The condition for the number of times is 3 times.

As shown in Table 1, according to the laminated films 30 of Examples 1 and 2, it was confirmed that the interlayer peel strength was within the preferable range shown in the embodiment before and after sealing. According to the laminated film 30 of Comparative Example 1, it was confirmed that the delamination strength after sealing was not within the preferable range shown in the embodiment. The interlaminar peel strength after sealing of the laminated film 30 of Comparative Example 1 was over 2.0 N/15 mm. According to the laminated film 30 of Comparative Example 2, it was confirmed that the delamination strength both before and after sealing was not within the preferable range shown in the embodiment. The interlayer peel strength of the laminated film 30 of Comparative Example 2 before and after sealing was more than 2.0 N/15 mm.

Note that the above embodiments are illustrative of the forms that the laminated film and package related to the present invention can take, and are not intended to limit the forms. Laminated films and packages related to the present invention may take forms different from those illustrated in the embodiments. As an embodiment, if the interface at which delamination occurs is the joint surface between the polyethylene terephthalate layer 43 and the extruded ethylene/methacrylic acid copolymer layer 60, some of the other components may be replaced, changed, or omitted. A configuration in which a new configuration is added to the embodiment is also possible. It was confirmed that even in these modified forms, the delamination strength showed the same tendency as in the example.

From the above, by using the laminated film of the present invention as a lid material for packaging containers for foods, medicines, etc., the upper layer film (release layer) can be easily delaminated from the lower layer film (remaining layer after peeling) during use, and the peeling can be performed easily. It was confirmed that the interface could be kept sanitary.

1... Package 10... Container 12... Opening 30... Laminated film 30B... Peeling start part 40... Lower layer film 41... First layer 42 laminated on the lower layer film... - Intermediate layer 43 laminated on the lower layer film...Polyethylene terephthalate layer 43A...Edge 50...Upper layer film 51...First intermediate layer 52 laminated on the upper layer film...Laminated on the upper layer film Second intermediate layer 53...Second layer 60 laminated on the upper film...Extruded ethylene/methacrylic acid copolymer layer 60A...Edge 100...Contents

Claims (5)

A laminated film used for a lid material that covers the opening of a flanged molded container and is hermetically sealed with the flange portion at the periphery of the molded container,
The lid material consists of two laminated films, an upper layer and a lower layer ,
The lower layer has a first layer and a polyethylene terephthalate layer ,
The upper layer includes an extruded ethylene methacrylic acid copolymer layer at least partially bonded to the non-corona-treated surface of the polyethylene terephthalate layer, and a second layer,
The peel strength between the polyethylene terephthalate layer and the extruded ethylene/methacrylic acid copolymer layer is 2.0 N/15 mm or less,
The lower layer is a laminated film configured to maintain the opening in a closed state when the upper layer is peeled from the lower layer. A laminated film used for a lid material that covers the opening of a flanged molded container and is hermetically sealed with the flange portion at the periphery of the molded container,
The lid material consists of two laminated films, an upper layer and a lower layer ,
The lower layer has a first layer and an extruded ethylene/methacrylic acid copolymer layer ,
The upper layer includes a polyethylene terephthalate layer having at least a portion of the uncorona-treated surface joined to the extruded ethylene methacrylic acid copolymer layer, and a second layer,
The peel strength between the extruded ethylene/methacrylic acid copolymer layer and the polyethylene terephthalate layer is 2.0 N/15 mm or less,
The lower layer is a laminated film configured to maintain the opening in a closed state when the upper layer is peeled from the lower layer. The laminated film according to claim 1 or 2, comprising a peel initiation portion where the polyethylene terephthalate layer and the extruded ethylene/methacrylic acid copolymer layer are not joined. 4. The laminated film according to claim 3, wherein one edge of the polyethylene terephthalate layer and the extruded ethylene/methacrylic acid copolymer layer protrudes from the other edge of the peel initiation portion. The laminated film according to any one of claims 1 to 4, wherein the first layer includes a sealant layer.

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