JPH0530706B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an easily openable sealed container, and more specifically, the container can be reliably and stably opened from the outside by hand, and The present invention relates to an easily openable sealed container that has a peel strength from the center of the container that is large enough to withstand an increase in internal pressure due to retort sterilization, sterilization of bolts, etc., and drop impact.

(Prior art and its problems) Conventionally, heat-seal packaging bodies have been widely used in many fields such as food packaging, and in particular those that can be peeled off at the heat-seal interface are easy to open or peelable heat-seal lids. It is still widely used as.

In a peelable type container, sealing performance and unsealing performance are in a contradictory relationship, and if the sealing performance is designed to withstand an increase in internal pressure during retort sterilization, the unsealing performance will be impaired. For example, in Japan, for heat-sealed packages whose contents have been subjected to retort sterilization, the sealing strength of the heat-sealed part is required to be at least 2.3 kg/15 mm width, and the seal strength between the container body and lid must be at least 2.3 kg/15 mm width. When the seal strength reaches this value, it becomes difficult to manually peel off the heat-sealed interface between the two.

As a solution to this problem, JP-A-62-
Publication No. 251363 states, ``In a peel container consisting of a multilayer container body formed of a multilayer sheet and a top film adhered at the flange portion of the container body, the interlayer adhesive force between the inner and outer layers of the container body is determined by A "simple peel container" is provided, characterized in that the container is constructed such that the adhesive strength is smaller than the adhesive force between the flange part and the top film, and a notch is provided in the inner layer of the flange part on the side of the container opening.

The above-mentioned container has a heat seal strength of 2.3 kg/15 mm width or more from the center of the container to the outside.
Although it is significant because it allows easy opening from the outside, peeling after opening is a problem. Generally, many people peel off the lid in the same direction from the beginning to the end of the opening, and this tendency seems to be particularly strong when opening a container that is easy to start. When the container described above is opened in the same direction from when the lid is peeled off to when it is removed, the peak opening force at the end of opening (secondary opening force) is higher than the peak opening force at the beginning of opening (primary opening force). ) is larger. Therefore, even if the lid can be easily peeled off at the beginning of opening, a large amount of force is required at the final stage to remove the lid from the container, causing the problem that the contents may fly out from the container. be. This problem becomes particularly noticeable when the contents are liquid.

Another problem with the above-mentioned containers is that they are subject to restrictions on the structure and manufacture of the containers, such as the need to perform score processing on the containers. In order to perform scoring on the inside of the peripheral area for heat sealing, there are restrictions on the container material used. For example, in laminated containers with an intermediate layer of metal foil such as steel foil, it is difficult to prevent rust from forming in the scoring area. In addition, in order to provide the above score, the area of the container flange inevitably increases, which is undesirable from the viewpoints of an increase in the amount of container material used, an increase in the bulk of the package, and appearance characteristics. .

Additionally, in general, in easily openable heat-sealed containers, simply having an easily peelable seal on the heat-sealed portion does not necessarily mean that the unsealing will be easy. It is necessary to effectively concentrate stress at the opening initiation portion of the easily peelable seal portion.

(Object of the Invention) Therefore, the present invention provides an easy-to-open package in which both the primary opening force and the secondary opening force are reduced without marking a score, and the container can be opened from the outside reliably and stably by hand. The purpose of the present invention is to provide a heat-sealable sealed container.

In addition, the present invention provides an easy-to-open heat seal that has a high peeling or breaking strength from the center of the container, for example, 2.3 kg/15 mm width or more, and can withstand increased internal pressure due to retort sterilization and the impact of dropping. The purpose is to provide a container.

(Structure of the Invention) That is, according to the present invention, a cup-shaped container having a heat-sealing flange and a lid are sealed by heat sealing, and the sealing portion is interposed between the flange, the lid, and the lid. It has a laminated structure with an intermediate film, and the intermediate film extends inward from the sealing part at least near the opening end of the circumferential sealing part and the opening inside the sealing part, and is not bonded to the lid and the container. There is a tight seal between the intermediate film and the lid, and an easily peelable seal between the intermediate film and the flange, and the inner peripheral edge of the easily peelable seal part is a tight seal. The intermediate film is located inside the container than the inner peripheral edge of the container, and at the opening start position, the intermediate film protrudes from the flange together with the lid as a gripping part, or the outer peripheral edge of the easily peelable seal part is tight. There is provided an easily openable container characterized in that the seal portion is located at the same level as the outer circumferential edge of the seal portion or further inside the container.

(Function) Hereinafter, the function of the present invention will be explained in detail based on specific examples shown in the accompanying drawings.

In FIG. 1 showing an example of the container of the present invention, this container is composed of a cup-shaped container body 2 having a heat-sealing flange 1 and a lid 3, with an intermediate portion between the flange 1 and the lid 3. A film 4 is provided.

An example of the planar structure of this intermediate film 4 is shown in the second-
Shown in Figure A.

That is, the intermediate film 4 has a circumferential sealing portion 10.
and an opening 12 formed through an extension 11 extending from the sealing part 10 toward the center of the container. The intermediate film 4 is heat-sealed between the flange 1 and the lid 3 at the sealing portion 10, and the film 4 is not bonded to the lid 3 and the container body 2 at the extension portion 11.

In addition, the opening 12 provides an easy-to-open seal in which the force generated inside the container during the sterilization process of a retort or the like or during a fall collision acts on the lid 3 through the opening 12 and directly acts on the intermediate film 4. This serves to prevent damage caused by peeling off from the portion 31. Furthermore, when filling the container body 2 with the contents after attaching the intermediate film 4 to the container body 2, the opening 12 becomes a filling port for filling the contents into the container body 2.

In the present invention, it is sufficient that the extension part 11 exists at least near the unsealing end part 20, and as long as such an extension part 11 is formed, for example, as shown in FIG. 2-A, The opening 12 is not limited to the form concentrically formed, and the second
- The opening 12 may be formed eccentrically toward the opening start part 21 as shown in Figure B, and the second
As shown in Fig. C, the opening 12 may be formed by a cut such as a cross cut. Furthermore, it may be a combination of hole-like openings and cuts, or a mesh shape.

This extension part 11 serves to prevent the sealing part 10 from being contaminated by the contents filled in the container when the lid 3 is heat-sealed onto the sealing part 10 on the periphery of the intermediate film 4. have.

Therefore, especially when the filling contents are liquid, it is desirable that the extension part 11 is formed over the entire inner circumference of the sealing part 10, as shown in FIG. 2-A.

Further, according to the present invention, since the extension portion 11 is formed in the vicinity of the opening end portion 20, the lid 3 is finally peeled off by a small secondary opening force. This effect will be described later.

Returning to FIG. 1 again, a tight seal 30 is formed between the intermediate film 4 and the lid 3, while an easy-to-open seal 31 is formed between the intermediate film 4 and the flange 1. .

In the present invention, the inner circumferential edge 32 of the easy-to-open seal 31 is the inner circumferential edge 3 of the tight seal 30.
It is important that it is located inside the container rather than No. 3.

That is, in FIG. 3 showing a state in which a peeling force P is applied from inside the container, the intermediate film 4 is not bonded to the lid 3 at a portion inside the inner circumferential edge 33 of the tight seal 30; Easy-peel seal 3
It is in a state where it is adhered to the flange 1 via 1.
Therefore, the force generated during a sterilization process such as a retort or during a fall collision acts on the tight seal 30 through the opening 12 of the intermediate film 4, and as a result, a large heat seal strength (for example, 2.3 kg/15 mm width or more) is achieved. sealing performance), and can withstand increased internal pressure due to retort sterilization and the impact of dropping.

For example, as shown in FIG. 4, contrary to the present invention,
When the inner edge 32 of the easily peelable seal 31 is located outside the container than the inner edge 33 of the tight seal 30, the film 4, which is not bonded to the flange 1, Since the inner circumferential portion is adhered to the lid 3 via the tight seal 30, the peeling force or breaking force P applied to the lid 3 from the inside of the container acts on the easily peelable seal 31, and as a result, the main It will be understood that the large peeling or breaking strength as in the invention cannot be obtained.

Further, in the present invention, the intermediate film 4 is integrated with the lid 3 at the opening start part 21 to form a grip part 40, and is in a state of protruding further to the outside of the container than the flange 1 (see FIG. 1).

That is, when the grip part 40 is held in the hand and pulled upward, force acts directly on the easily peelable seal 31, resulting in a peel strength of, for example, 2 kg/15 mm width or less, making it possible to reliably and stably peel and open the seal by hand. easily done.

In this case, instead of protruding the intermediate film 4 to the outside of the container beyond the flange 1 to form the gripping part 40, the outer peripheral edge 41 of the easily peelable seal 31 is
It may be located at the same position as the outer circumferential edge 42 of the tight seal 30 (see Fig. 5-A), or may be located inside this (see Fig. 5-B).

Even in this embodiment, if the grip part 40 is held in the hand and lifted upward, the peeling force acts on the easily peelable seal 31, so that the seal can be opened easily. In particular, in order to effectively concentrate the peeling force on the outer peripheral edge 41 of the easily peelable seal portion 31,
Preferably, the embodiment shown in FIG. 5-B is better than the embodiment shown in FIG. 5-A.

Further, according to the present invention, as described above, in the vicinity of the unsealing end portion 20, the extension portion 11 is formed on the inner peripheral side of the intermediate film 4, and is not bonded to the flange 1 and the lid 3. Also in this portion 20, the inner circumferential edge 33 of the tight seal 30 and the inner circumferential edge 32 of the easily peelable seal 31 have the positional relationship shown in FIGS. 1 and 3.

A state in which an unsealing force is applied to this unsealing end portion 20 is shown in FIGS. 6-A and 6-C.

That is, as the lid 3 is peeled off from the unsealing start part 21, peeling progresses from the easily peelable seal 31, as explained in relation to FIG.
0, as shown in FIGS. 6-A and 6-C, the extension part 11 in the free state is attached to the lid 3.
As a result, an opening force (secondary opening force) is applied to the easy-open seal 31, making it possible to easily peel off the lid 3 together with the intermediate film 4.

In this case, when the free extension 11 is not formed, the secondary opening force acts on the tight seal 30 as shown in FIGS. 6-B and 6-D, so that the lid 3 is finally closed. An extremely large amount of force is required to peel it off. At this time, the secondary opening force is determined by the distance between the inner peripheral edges 32 and 33 of the easy-open seal portion 31 and the tight seal portion 30, the adhesive strength of the easy-open seal portion 31, and the material properties of the intermediate film 4. Although it varies depending on conditions such as the shape of the container and the shape of the container, it is generally 1.5 times the primary opening force.
The value will be 2.5 times higher. Furthermore, depending on the above conditions, the intermediate film 4 may break near the inner peripheral edge 33 of the tight seal portion 30 where stress is likely to be concentrated, and a portion of it may remain on the flange 1 after opening. There is.

As described above, according to the present invention, the secondary opening force is also reduced, making it possible to finally peel off the lid 3 with a small force, and the intermediate film 4 can be removed without a portion remaining on the flange 1. Since it can be completely peeled off together with 3, the appearance of the container will not be damaged.

(Preferred Embodiment of the Invention) In the present invention, in order to form a tight seal on one side of the intermediate film and an easily peelable seal on the other side, the intermediate film and the inner lid material,
Alternatively, use the difference in heat seal strength with the container inner material.

For example, if the intermediate film is a polypropylene film and the inner surface of the lid is made of polypropylene, a tight seal will be formed. In addition, the inner surface of the container is made of polypropylene and other polymers, such as polyethylene, ethylene-vinyl acetate copolymer,
If it is made of a blend of ethylene-propylene rubber or the like, an easily peelable seal will be formed.

Further, if the intermediate film is made of a laminated structure of polypropylene and the blend layer, and both the inner surface of the lid and the inner surface of the container are formed of polypropylene, if the blend layer of the intermediate film is made to face the container side, the container An easily peelable seal is formed on the inner surface, and a tight seal is formed on the lid.

Examples of these are polyethylene, polyester,
This also applies to heat-sealable resins such as polyamide.

It is also known that polyolefine films have heat-sealing properties for certain coatings. That is, polyolefin film exhibits excellent heat sealing properties compared to coating films in which oxidized polyethylene or acidic olefin resin is dispersed. By providing this coating on the inner surface of the lid or container, and adjusting the amount of dispersed polyethylene oxide or acid-modified olefin resin, or the amount of third component that inhibits heat-sealing properties, it is possible to coat one side of the polyolefin film. A tight seal can be formed on the other side and a peelable seal can be formed on the other side. This tendency also applies to resins such as polyester and polyamide that exhibit heat sealability with paints.

Macroscopically, peeling at the easily peelable seal part appears to be due to interfacial peeling between the intermediate material and the inner surface material of the container, but microscopically, it is due to interfacial peeling at the heat seal interface and this interface. Failure phenomena such as cohesive failure or delamination in the vicinity may occur singly or in combination.

The positions of the inner and outer edges of the easily peelable seal part and the inner and outer edges of the tight seal part can be controlled by any means. Most simply, by controlling the shape and position of the heat-sealing head when heat-sealing the intermediate material to the lid or container flange, the positions of the inner and outer edges thereof can be controlled.

Alternatively, a non-adhesive coating that defines the inner and outer edges of the heat-sealed portion may be applied to the flange surface, inner surface of the lid, or By applying it to the intermediate film, it is possible to control the position of the inner and outer edges of the heat-sealed portion.

In the present invention, heat-sealing surfaces with different adhesion strengths such as a tight seal portion and an easily peelable seal portion are provided via an intermediate film, and the positions of their inner and outer edges are regulated, or By protruding the film to the outside of the container as a gripping portion, it is possible to provide a predetermined difference between the peeling or breaking strength from the center of the container and the peeling strength from the outside of the container. Furthermore, this difference can be set arbitrarily by appropriately selecting conditions such as the adhesive strength of the tight seal part and the easily peelable seal part, the positional relationship between the inner and outer edges of each seal part, and the material strength of the intermediate film. be done. For example, in order to achieve both good sealing performance and unsealing performance, the difference in adhesive strength between the tight seal part and the easily peelable seal part should be large, for example, the tight seal part should be 2.5 kg/15 mm or more, preferably 3Kg
The above is 0.2Kg/15mm for the easily peelable seal part.
More than 2Kg/width less than 15mm, preferably 0.4Kg/15mm
The above should be 1.5 kg/15 mm or less, and the positional deviation of the inner edge of each seal part should be 0.5 mm or more, preferably 1 mm or more, and practically 5 mm or less. In addition, in order to reduce the secondary opening force at the time of opening, the intermediate film should have material properties or thickness that are difficult to stretch and break. In other words, by selecting such a material, the intermediate film follows the lid and is easily lifted up when the opening is completed, and the secondary opening force is effectively reduced.

Furthermore, the length of the extended portion formed on the intermediate film at the unsealing end portion, that is, the portion that is not bonded to the lid and container, is at least 1 mm, particularly 3 mm.
It is preferable to set it to mm or more.

The container body and lid may be made of any container-forming material known per se, such as resin, metal, paper, glass, ceramic, or a laminate thereof. Suitable container bodies and lids are made of at least the inner surface of an intermediate film and a resin having heat-sealing properties, such as, but not limited to, low-medium, high-density polyethylene, isotactic polypropylene, Propylene-
Olefin resins such as olefin resins graft-modified with ethylene copolymers, ethylene-vinyl acetate copolymers, ethylenically unsaturated carboxylic acids or their anhydrides; polyamide or copolyamide resins with relatively low melting points or softening points; It is made of polyester or copolyester resin with a relatively low melting point or low softening point; polycarbonate resin, etc. Moreover, these resins may be blended with an inorganic filler.

The container body may be a container formed from these resins alone, or may be a laminated container including a metal foil such as aluminum, steel, tin plate, etc. as an intermediate layer. Further, it may be a so-called well-known metal container in which these metal materials are coated with a resin known per se such as a thermosetting resin or a thermoplastic resin.

The lid body is made of metal foil such as aluminum foil, tin foil, steel foil, or tin foil, high oxygen barrier resin film such as ethylene-vinyl alcohol copolymer, vinylidene chloride resin, or nylon resin, biaxially oriented polyethylene terephthalate film, The base material may be a biaxially stretched nylon film, a thermoplastic resin film such as a polycarbonate film, various papers, or a laminate thereof, and the heat-sealable resin layer described above may be laminated thereon as an inner material.

The intermediate film is a film made of one or more layers of the above-mentioned heat-sealable resin, and its thickness is at least the same as that for opening, retort sterilization, and retort sterilization.
It must be able to withstand the force associated with falling impact, etc., and generally varies depending on the material, but is generally 15 to
A thickness of 300 μm, particularly in the range of 30 to 100 μm, is desirable.

Any method may be used to manufacture the intermediate film, and if the intermediate film is a single layer, the in-die extrusion method and compression molding method are also possible, but if thickness variations are taken into consideration,
A casting method or an inflation method is preferable. In addition, if the intermediate film is multi-layered, it may be possible to use a co-extrusion method using a multi-layer die, a method of extruding and coating the necessary layers on a pre-formed base material, or a method of heat lamination or sand lamination between the base materials. Examples include a method of laminating.

The present invention is particularly useful for applications in which the contents are sterilized by retort or boiling, or by hot filling.In this case, from the standpoint of heat resistance, the inner material of the container and lid may be made of polypropylene resin. is common. Particularly suitable intermediate films for this application have a thickness of 15 to 300 μm, especially 30 to 300 μm.
A polypropylene layer in the range of 100 μm and an ethylene content of 10 with a thickness of 1 to 100 μm, in particular 3 to 50 μm.
% of a crystalline propylene-ethylene random copolymer and a layer of a 90:10 to 50:50 blend of polyethylene.

The polypropylene layer is preferably made of homopolypropylene, or may be made of a propylene-ethylene block copolymer with an ethylene content of 10% or less. Alternatively, it is particularly desirable to have a crystalline propylene-ethylene random copolymer layer with an ethylene content of 10% or less on the outside of this layer in order to improve the heat-sealability of the surface that forms a tight seal. Further, different components may be blended in the polypropylene layer to the extent that the physical properties of the film are not deteriorated, and the blend layer may also contain propylene-ethylene rubber or the like as a third component.

(Effects of the Invention) According to the present invention, an intermediate film is interposed between the lid and the container, a tight seal is formed between the film and the lid side, and a tight seal is formed between the film and the container flange side. forming an easily peelable seal part,
By regulating the positions of these inner and outer edges or by making the film protrude as a gripping part, it is possible to peel the container from the center side without carving a score on the container or lid. Alternatively, it has become possible to provide a predetermined difference between the breaking strength and the peeling strength from the outside of the container.

Furthermore, at the beginning and end of unsealing, a peeling force is applied to the easily peelable seal part to facilitate the final peeling off of the lid at the beginning and end of unsealing.
It has become possible to do this reliably and stably.

Further, in the present invention, since the intermediate film is completely peeled off together with the lid, the appearance of the container after opening is not damaged.

The invention is illustrated by the following example.

Examples and Comparative Examples As a lid material, a 12 μm biaxially stretched polyethylene terephthalate film and a 7 μm soft aluminum foil were laminated with a urethane adhesive on the aluminum side of the base material, and as a heat seal layer, a 70 μm film with an ethylene content of 4% was used. A coextruded film (thickness ratio 7:3) consisting of a propylene-ethylene block copolymer and a propylene-ethylene random copolymer with an ethylene content of 4% is laminated with a urethane adhesive so that the random copolymer side becomes the heat sealing surface. prepared.

To make a cup-shaped container, a 75 μm surface-treated steel foil is laminated with a 40 μm unstretched polypropylene film on one side and a 70 μm unstretched polypropylene film on the other side using a urethane adhesive, and then this laminate is placed so that the 70 μm film side becomes the heat-sealing surface. A circular container with an outer diameter of 75 mm was prepared by deep drawing and forming a flange for heat sealing with a width of 5 mm.

The following two types of intermediate films were prepared. One is a 56 μm homogeneous polypropylene layer (layer A),
Consisting of a 4 μm blend layer (layer B) made by blending a propylene-ethylene random copolymer with an ethylene content of 4%, 36% by weight of linear low density polyethylene, and 2% by weight of ethylene-propylene rubber.
This is a two-layer coextruded film (film A). Also, one is 10μm ethylene content 4%
propylene-ethylene random copolymer layer (A
layer), a 45 μm homogeneous polypropylene layer, and a propylene-ethylene random copolymer with 4% ethylene content and 35% by weight linear low-density polyethylene.
This is a three-layer coextruded film (film B) consisting of a 5 μm blend layer (layer B).

A sealed container of the type shown in FIG. 1 was produced using these lid materials, cup-shaped containers, and intermediate films. As for the production order, first the intermediate film B
The layer side was thermally bonded (easily peelable seal) to the heat-sealing flange surface of the cup-shaped container at 200° C. for 0.8 seconds, and a filling opening was provided inside this thermally bonded area. Note that the filling opening is of the type shown in Figure 7-A in which the opening is provided in the center of the container, the type shown in Figure 7-B in which the opening is eccentric, and the type shown in Figure 7-C with a notch. It was of the type shown in the figure. Further, as for the type shown in Fig. 7-A, the size of the opening and the intermediate film were changed. 15 containers were made for each condition. After this, the container was filled with water to approximately 90% of its total volume, and the A layer side of the intermediate film and the inner surface of the lid were heat sealed (tight seal) at 195°C for 1.5 seconds twice to seal the container. .

Note that heat sealing was performed by regulating the shape and position of the heat seal head so that the easily peelable seal portion and the tight seal portion were concentric with the outer shape of the circular heat seal flange. At this time, the inner diameter and outer diameter of the easily peelable seal part are 66 mm and 73 mm, and the inner diameter and outer diameter of the tight seal part are 69 mm and 75 mm.
mm. Furthermore, the shapes of the pedestal and the heat seal head were devised so that the intermediate film and the gripping part of the lid were bonded to each other on the outside of the flange at the opening start part.

The peel strength and unsealing strength of the thus obtained sealed and filled container were measured using a tensile tester after retort sterilization at 120°C for 30 minutes. To measure peel strength, cut out a 15 mm wide strip perpendicular to the direction of the heat seal, place the lid side of the strip between the top chuck and the side wall of the cup between the bottom chuck, and cut it up and down at a speed of 300 mm/min. I dragged myself along. In addition, the opening strength is determined by fixing the container at a 45° angle to the cross head.
At the same time, hold the gripping part for opening the lid and intermediate film in the upper chuck (the angle between the top surface of the container and the gripping part of the lid is 45°) and pull it up and down at a speed of 300 mm/min. I held out. Table 1 shows the average values of peeling or breaking strength from the inside of the container, peeling strength from the outside at the beginning of opening, and opening strength.
Furthermore, FIG. 8 shows an example of a measurement chart of the opening strength of Example 1 and Comparative Example 1.

An object of the present invention is to provide an easy-to-open sealed container that can withstand internal pressure increase or drop impact during retort sterilization, and can be opened easily, reliably and stably from the beginning to the end. However, as can be seen from Table 1, the peeling or breaking strength from the inside of the container is 2.3Kg/15mm width or more, which is strong enough to withstand the increase in internal pressure during retort sterilization, and the peeling strength from the outside is around 1Kg/15mm width. This is an easy-to-open seal, and the primary opening force indicates a value that allows for easy opening. However, the secondary opening force is high in Comparative Examples 1 and 2, and it can be seen that it is reduced by protruding the intermediate film inside the container as in Examples 1 to 7. Regarding the containers of Comparative Example 2, 5 out of 15 had a portion of the intermediate film remaining on the flange surface at the end of the unsealing.

Furthermore, when these containers were actually opened by five panelists, two panelists spilled the contents upon completion of opening the container in Comparative Example 1, and four panelists spilled the contents in the container in Comparative Example 2. In addition, some of the containers of Comparative Example 2 had a portion of the intermediate film remaining on the flange surface of the unsealed end.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional structural diagram illustrating an easily openable sealed container of the present invention, and FIGS. 2-A, 2-B, and 2-C are perspective views showing examples in which an intermediate film is applied to the main body. 3 and 4 are cross-sectional views showing a state in which a peeling force is applied from the inside to the inner sealing part of the container, and FIGS. 5-A and 5-B are sectional views of the container. It is a cross-sectional view at the opening start part of the sixth
-A and 6-B are perspective views showing the state at the end of unsealing, and Fig. 6-C is a sectional view showing the state near the end of unsealing in Fig. 6-A. Figure D is a cross-sectional view showing the state near the end of opening in Figure 6-B, and Figures 7-A, 7-B, and 7-C are of the containers used in Examples or Comparative Examples. FIG. 8 is a plan view showing an application example of the intermediate film, and FIG. 8 is a graph illustrating changes in opening force from the start to the end of opening of the containers used in Example 1 and Comparative Example 1. The stamped number 1 is the heat-sealing flange, 2 is the container body, 3 is the lid, 4 is the intermediate film, 11 is the extension of the intermediate film that protrudes inward from the sealing part of the container, and 12 is provided on the intermediate film. Aperture,
20 is an opening end part, 21 is an opening start part, 30 is a tight seal part, 31 is an easy-to-open seal part, 32 is an inner edge of the easy-to-open seal part, 33 is an inner edge of the tight seal part, Reference numeral 41 indicates an outer peripheral edge of the easily openable seal portion, and reference numeral 42 indicates an outer peripheral edge of the tight seal portion.

【table】

Claims (1)

[Scope of Claims] 1. A cup-shaped container having a heat-sealing flange and a lid sealed by heat sealing, wherein the sealing portion is a lamination of the flange, the lid, and an intermediate film interposed between them. The intermediate film has a circumferential sealing portion, an opening inside the circumferential sealing portion, and an extension portion that extends inward from the sealing portion at least near the opening end portion and is not bonded to the lid or the container. However, there is a tight seal between the intermediate film and the lid, and an easily peelable seal between the intermediate film and the flange, and the inner edge of the easily peelable seal part is the inner edge of the tight seal part. The intermediate film is located inside the container from the rim, and at the opening start position, the intermediate film protrudes from the flange to the outside of the container together with the lid as a gripping part, or the outer peripheral edge of the easily peelable seal part is on the outer peripheral side of the tight seal part. An easy-to-open container characterized by being located at the same level as the edge or further inside the container. 2. The container according to claim 1, wherein the extension portion is provided over the entire inner circumference of the sealing portion. 3. The container according to claim 1, wherein the opening is a notch provided in the intermediate film. 4. A food package obtained by filling the easily openable container according to claim 1 with food and sealing the container in a sterilized or sterilized state.