JPH0534234B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for manufacturing an easily open sealed container, and more specifically, the present invention relates to a method for manufacturing an easily open sealed container, and more specifically, the peel strength from the center side of the container is determined by, for example, retort sterilization or dropping. The present invention relates to a method for producing an easily openable sealed container that is strong enough to withstand impact, etc., and whose peel strength from the outside of the container is maintained at an easily openable seal strength so that it can be opened by hand.

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

For heat-sealed packages whose contents are subjected to retort sterilization, the seal 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 this value. When the heat-sealed interface between the two is reached, it is difficult to peel off the heat-sealed interface between the two.

To solve this problem, a heat-sealing inner material layer is provided on the inner surface of the container body, and the inner layer and the inner layer are easily peelable.
A score is provided to cut this inner material layer closer to the center of the container than the heat-sealed part, and the seal strength from the center to the outside is at least 2.3 kg/15 mm width, while making it easy to open from the outside. Heat seal containers have already been proposed.

(Problems to be Solved by the Invention) The above-mentioned easy-to-open heat-sealed container is significant as it provides easy-to-open packaging while maintaining sealing strength of 2.3 kg/15 mm width or more. The problem is that there are restrictions on the structure and manufacturing of the container, such as the need to perform score processing on the container. In addition, in order to score the inside of the area to be heat-sealed, there are restrictions on the container material that can be used (for example, materials that corrode or rust, such as steel foil, are difficult to use) and the container flange must be This increases the area of the container, 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 poor appearance characteristics.

Therefore, an object of the present invention is to provide a container with a high peel strength from the center side, such as 2.3 kg/15 mm width or more, so that it can withstand increased internal pressure during retort sterilization or drop impact. , an easy-to-open sealed container whose peel strength from the outside of the container is maintained at the easy-to-open heat-seal strength at the opening start position is manufactured by providing a specific intermediate film between the container and the lid. This is to provide a way to do so.

Another object of the present invention is to provide a method for producing an easily openable sealed container in which the above-described anisotropy of peel strength is achieved without marking the container or container lid with a score.

Still another object of the present invention is to provide a method in which the intermediate film is reliably and smoothly applied to a portion of a container to be heat-sealed.

(Means for Solving the Problems) According to the present invention, the portion of the single-layer or multilayer cup to be heat-sealed, including at least the opening start position, has a surface whose adhesive strength with the cup is easily peelable. a step of thermally bonding an intermediate film; a step of filling a cup provided with the intermediate film with a content; and an inner surface of the cup filled with the content capable of forming a tight seal with the intermediate film or further with a portion of the cup to be heat sealed. The process consists of applying a lid with a layer and thermally bonding the cup and the lid at the area to be heat-sealed, and thermally bonding the intermediate film to the area to be heat-sealed and bonding the intermediate film to the inner surface layer of the lid. Adhesion,
The inner edge of the seal between the intermediate film and the cup is located closer to the center of the container than the inner edge of the seal between the intermediate film and the lid inner layer, and A method for producing an easily openable sealed container, characterized in that the outer peripheral edge of the sealing portion with the intermediate film is located closer to the center of the container than the outer peripheral edge of the sealing portion with the inner lid layer. is provided.

Further, in the first thermal bonding step of the present invention, it is desirable to apply the intermediate film to the portion of the cup to be heat sealed from a continuous film (original film), and the following method is preferably used for this purpose.

(i) Supplying the intermediate film in the form of a continuous film to the portion of the cup to be heat-sealed, thermally bonding the intermediate film and the portion to be heat-sealed, and applying the intermediate film along the inner and outer contours. A method of separating the unnecessary portion by cutting the cup, or further thermally bonding the cup to the intermediate film on the part to be heat-sealed: (ii) Cutting the continuous intermediate film along the inner circumferential contour. The separated intermediate film is supplied to the part of the cup to be heat-sealed, thermal bonding is performed between the intermediate film and the part to be heat-sealed, and then the intermediate film is stretched along the outer circumferential contour. Method for cutting and separating unnecessary parts: (iii) Hold the continuous intermediate film cut along the inner and outer contours and place it on the part of the cup to be heat sealed. alms,
A method of thermal bonding between the intermediate film and the cup: (iv) A continuous intermediate film is fed above the cup, and the unnecessary part is separated by cutting the intermediate film along the inner circumferential contour. A method in which the separated intermediate film and the cup are brought into contact with each other to thermally bond them together, and then the intermediate film is cut along the outer circumferential contour to separate unnecessary parts: (v) The intermediate film is cut into a continuous film. The intermediate film is supplied only to the opening start part of the heat-sealed part of the cup and its vicinity, and the intermediate film is thermally bonded to the opening start part and cut along the outer circumferential contour of the intermediate film. A method of thermally bonding between the opening part and the opening part.

(Function) In manufacturing the sealed container according to the present invention, the cup, the intermediate film, and the lid are formed by forming an easy-to-open heat seal between the intermediate film and the cup, and forming a tight seal between the intermediate film and the inner surface of the lid. The first feature is to select and combine them so that a seal is formed, which increases the seal strength from the center to the outside to 2.3Kg/15, which is called a tight seal.
While maintaining the strength of the width of mm or more, the opening force applied from the outside of the container at the opening start position can be controlled within a range called easy opening.

Next, in the method of the present invention, prior to filling the contents, the portion to be heat-sealed of the cup and the intermediate film are thermally bonded (first step), the contents are filled into the cup (second step), and the intermediate film is bonded. The second feature is that the provided cup and lid are thermally bonded (third step) in this order. By performing thermal bonding between the cup and the intermediate film and thermal bonding between the intermediate film and the lid in separate processes, it is possible to independently define the outline of the easily peelable heat seal area and the outline of the tight seal area. becomes.

That is, according to the present invention, the thermal adhesion between the intermediate film and the portion to be heat-sealed of the cup and the thermal adhesion between the intermediate film and the inner surface layer of the lid are performed so that the inner circumferential edge of the sealing portion between the intermediate film and the cup is connected to the intermediate film. The inner edge of the seal between the intermediate film and the cup is located closer to the center of the container than the inner edge of the seal between the intermediate film and the cup, and the outer edge of the seal between the intermediate film and the cup is located closer to the center of the container than the inner edge of the seal between the intermediate film and the inner layer of the lid. It becomes possible to perform heat sealing by setting the seal portion to be located closer to the center of the container than the outer circumferential edge of the seal portion, which further provides the following advantages.

First, since the peeling force from inside the container acts on the tight seal, a large breaking strength corresponding to the peeling strength of the tight seal can be obtained, but on the other hand, the peeling force from outside the container is easy at the opening start position. Since it acts on the easy-to-open seal part, it can be easily peeled and opened by hand with a relatively small peeling force corresponding to the peel strength of the easy-to-open seal part.

At this time, it is also important to thermally bond the intermediate film to the cup before filling the contents, and to thermally bond the intermediate film to the lid after filling the contents. In conventional heat-sealed containers, where the filling seal surface is the same as the seal surface that peels off when the container is opened, materials are selected with consideration to ease of opening and sealing, and heat-sealing conditions within a narrow range (temperature, pressure,
The sealing must be performed under conditions such as time, etc., making it extremely difficult to control the strength of the seal. Furthermore, when filling the container with contents, the contents may drip or adhere to the surface to be heat-sealed.
Due to the presence of foreign matter at the seal interface, it is difficult to avoid influences such as a decrease in seal strength and sealing performance. In the present invention, since two stages of heat sealing are performed in the above order, the easily peelable sheet seal is reliably made using a material that forms an easily peelable seal under conditions where no foreign matter is mixed in, and under heat sealing conditions that only consider ease of opening. On the other hand, even if the contents adhere to the sealing surface after filling, heat sealing can be performed using a material that forms a tight seal and under heat sealing conditions that take sealing performance into consideration, so there is no risk of foreign matter contamination. It is possible to prevent a decrease in seal strength and sealing performance.

Furthermore, by using the means (i) to (v) above, while supplying the intermediate film in the form of a continuous film (original film), the heat between the cup and the intermediate film is reduced in the first step of thermal bonding. Bonding can be performed smoothly and efficiently.

(Example) In FIGS. 1 and 2 for explaining the manufacturing process of the present invention, in the first step A, a cup 1
A circumferential intermediate film 3 is thermally bonded to the flange part (part to be heat sealed) 2 of the intermediate film 3.
The flange portion 2 and the easily peelable seal 4 are formed.
In this case, it is preferable that the outer peripheral edge 5 of the intermediate film 3 protrudes slightly outward from the outer peripheral edge of the flange portion 2. In the embodiment shown in FIG. 1, the inner circumferential edge 6 of the intermediate film 3 is provided so as to extend beyond the flange portion 2 and reach above the cup side wall portion toward the center. In the specific example shown in , the inner circumferential edge 6 of the intermediate film 3 is located on the flange portion 2 .

In the second step B, the contents 7 are filled hot or cold into the cup 1 to which the intermediate film 3 is thermally bonded.

Next, after replacing the atmosphere with steam or nitrogen as necessary, in a third step C, a lid 9 with an inner surface layer 8 is applied to the upper part of the cup 1, and the inner surface layer 8 and the intermediate film 3 are thermally bonded to bond them together. A tight seal 10 is formed between them. 1 and 2, the outer peripheral edge of the tight seal portion 10 is located outward from that of the easily peelable seal portion 4, and the inner peripheral edge of the easily peelable seal portion 4 is a tight seal. It will be understood that it is located closer to the center than that of the section 10.

In the present invention, in order to form a tight seal between the intermediate film and the lid and an easy-to-open seal between the intermediate film and the cup, it is necessary to Take advantage of the difference between

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 cup is made of polypropylene and other polymers, such as polyethylene, ethylene-vinyl acetate copolymer, Eylene-propylene rubber, ethylene-α
- If it is made of a blend such as an olefin copolymer, an easily peelable seal will be formed. Furthermore, if the intermediate film is made of a laminated structure of a polypropylene layer and the blend layer, and the inner surface of the lid and the inner surface of the cup are both made of polypropylene, the polypropylene layer side has a tight seal and the blend layer side has easy-to-open properties. A seal will form. These examples also apply to heat-sealable resins such as polyethylene, polyester, polyamide, polycarbonate, and the like.

It is also known that polyolefine films have heat-sealing properties for certain coating films. That is, polyolefin film exhibits excellent heat sealability compared to coating films in which oxidized polyethylene or acid-modified olefin resin is dispersed. By providing this coating on the inner surface of the lid or the cup, 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 an easy-to-open seal on the other side. This tendency also applies to resins such as polyester and polyamide that exhibit heat sealability with paints.

The intermediate film is generally 15 to 1000 μm, especially
Preferably, it has a thickness of 30 to 100 μm. A particularly suitable intermediate film for applications such as heat sterilization is a coextruded laminated film of a polypropylene blend having a polypropylene layer 11 on the lid side and a blend layer 12 on the container side, as shown in FIG.
In the blend layer 12, polyethylene, ethylene-vinyl acetate copolymer,
Ethylene polymers such as ethylene-propylene rubber and ethylene-α-olefin copolymer are 5 to 50
It is preferably contained in an amount of 10 to 40% by weight. The thickness of the blend layer is generally in the range of 2 to 50%, particularly 5 to 20% of the total thickness.

The cup used may be a single-layer or multi-layer cup made of container-forming materials which are known per se.
Suitable cups are those made of a resin having heat-sealing properties at least on the inner surface, such as low-medium-high density polyethylene, isotactic polypropylene, ethylene-propylene copolymer,
Olefin resin such as olefin resin graft-modified with ethylene-vinyl acetate copolymer, ethylenically unsaturated carboxylic acid or its anhydride: Polyamide or copolyamide resin with relatively low melting point or low softening point: Relatively low melting point It is made of polyester or copolyester resin having a low softening point.

The cup may be a container formed from these resins alone, or may be a laminated container containing a metal foil such as aluminum foil, steel foil, or tin foil as an intermediate layer. Furthermore, the cup may contain a high oxygen barrier resin such as ethylene vinyl alcohol copolymer, vinylidene chloride resin, or nylon resin as an intermediate layer instead of metal foil or the like. From the viewpoint of heat sterilization, the suitable cup has a thickness of 10 to 500 μm.
It is a multilayer cup with inner and outer polypropylene layers having a thickness of 5 to 200 μm, especially 20 to 100 μm, and an intermediate layer of metal foil having a thickness of 5 to 200 μm, especially 20 to 100 μm. Various methods can be used to form the cup depending on the material, such as press molding, solid state drawing, plug-assisted melt pressure or vacuum molding, injection molding, and the like. The shape of the cup is not limited to a cup shape, but may be in various shapes such as a tray shape.

The lid is made of metal foil such as aluminum foil, tin foil, steel foil, or tin foil, ethylene vinyl alcohol copolymer,
The base material is a high oxygen barrier resin film such as vinylidene chloride resin or nylon resin, a thermoplastic resin film such as biaxially oriented polyethylene terephthalate film, biaxially oriented nylon film, or polycarbonate film, various papers, or laminates thereof, etc. A material in which the above-mentioned heat-sealable resin layer is laminated as an inner material is preferably used. A lid material suitable for heat sterilization uses a metal foil and an inner layer made of polypropylene.

Although any method can be used to apply the intermediate film to the cup container, the means (i) to (v) above are preferably employed. This will be explained below.

Example 1 The process of applying the intermediate film to the entire circumference of the cup flange will be explained based on FIG. 4. The figure shows a method of temporarily adhering the intermediate film as it is to the cup, cutting off unnecessary portions of the intermediate film, and then performing the final adhesion. The shape of the cup is round.

The cup 1 is fixed on a pedestal 13 and is intermittently conveyed from left to right in the figure. First, the intermediate film 14 is unwound from the roll 15 and is temporarily bonded to the cup 1 by the heat seal head 16. Temporary gluing takes place on the flange flat part 2 of the cup 1. The adhesive strength at this time needs to be strong enough to withstand the next cutting process. Specifically, it depends on the adhesive width, but it is desirable to have a width of 0.2 kg/15 mm or more.

Next, the blades 17 and 18 rotate at high speed,
The unnecessary parts 19 and 20 of the intermediate film are cut off from the cup 1. The inner unnecessary part 19 is sucked upward, and the outer unnecessary part 20 is wound up on a roll 21.

Finally, the intermediate film 3 is permanently bonded by the heat-sealing head 22 from the flange flat of the cup 1 to its inner part 6.

The above steps of temporary adhesion, cutting out, and main adhesion are performed intermittently during cup transportation.

Example 2 The process of applying the intermediate film to the entire circumference of the cup flange will be explained based on FIG. 5. The figure shows a method in which an unnecessary portion on the inside of the intermediate film is cut off and then adhered to a cup, and then an unnecessary portion on the outside is cut off from the cup. The shape of the cup is round.

The cup 1 is fixed on a pedestal 13 and is intermittently conveyed from left to right in the figure. First, the intermediate film 14 is unwound from the roll 15, and the unnecessary inner portion 19 is cut off by the blade 17 rotating at high speed. The unnecessary portion 19 is sucked out to the right.

Next, the raw material from which unnecessary inner parts have been cut out is aligned with the cup, and the heat seal head 22
It is glued to cup 1 by. The bonding takes place on the flange flat 2 of the cup 1.

Finally, the outer unnecessary portion 20 is cut off from the cup 1 by the blade 18 rotating at high speed, and the roll 2
1. When the shape of the cup is other than round, a saw blade corresponding to the outer peripheral shape of the intermediate film is moved up and down.

The above-described cutting and gluing steps are performed intermittently during cup transportation.

Example 3 In Example 2, there were technical difficulties in terms of complete alignment between the cup and the original fabric from which the inner part was cut out. A method for improving this problem will be explained using FIG. 6. The figure shows a method in which the unneeded portion of the intermediate film is transported synchronously while facing the cup, the unnecessary inner portion is cut off, the unnecessary portion is then glued to the cup, and the unnecessary outer portion is then cut off from the cup. It shows. The shape of the cup is round.

On the outer periphery of the cup holder 13, an intermediate film support 23 is provided coaxially with the cup holder 13.
can be raised and lowered into the intermediate film support 23, and the upper surface of the intermediate film support 23 is located above the flange portion 2 of the cup 1 supported by the cup holder. In this state, the cup is intermittently conveyed from left to right in the figure. Intermediate film material 14
is unwound from the roll 15 and supplied onto the intermediate film support 23, and is bonded to the upper surface of the intermediate film support by the heat seal head 16a for position fixation. The unnecessary portion 19 inside is cut off by the blade 17 rotating at high speed, and the unnecessary portion 19 is sucked upward. Next, the cup holder 13 is raised, the intermediate film 3 and the cup flange 2 are brought into contact with each other, and the intermediate film 3 and the flange 2 are thermally bonded by the heat seal head 22. Finally, the outer unnecessary portion 20 is cut off from the cup 1 by a blade 18 rotating at high speed and wound onto a roll 21.

The above-described cutting and gluing steps are performed intermittently during cup transportation.

Example 4 The process of applying the intermediate film to the entire circumference of the cup flange will be explained based on FIG. 7. The figure shows that after cutting the intermediate film into the final shape from the original film, aligning the intermediate film with the cup,
Shows how to glue. The shape of the cup is round.

The cup 1 is fixed on a pedestal 13 and is intermittently conveyed from left to right in the figure. First, the original film 14 of the intermediate film is unwound from the roll 15, and the jig 2
4, it is fixed by suction. Thereafter, the intermediate film 3 is cut out by blades 17 and 18 that rotate at high speed.

Next, the cut out intermediate film 3 is held in a jig 24.
The intermediate film 3 is conveyed to the cup 1 while being fixed to the cup 1 by the horizontal, rotational, and vertical movements of the jig 24, and the intermediate film 3 and the cup 1 are aligned and placed on the cup. Thereafter, the jig 24 returns to its original position by vertical movement, rotational movement, and horizontal movement.

Finally, the intermediate film 3 is glued to the cup 1 by means of a heat seal head 22. The bonding takes place from the flange flat 2 of the cup 1 to its inside.

The above intermediate film conveyance and adhesion process is as follows:
This is done when the cup is being transported intermittently.

Example 5 The process of applying the intermediate film only to the opening start portion of the cup flange will be explained based on FIG. 8. The figure shows a method for cutting the original fabric from the cup after adhering the tip of the intermediate film to the opening start part of the cup.

The cup 1 is fixed on a pedestal 13 and is intermittently conveyed from left to right in the figure. First, the raw fabric 14 slit to the required width is unwound from the roll 15, and is projected by the roll 25 to the opening starting portion 2a of the cup as much as necessary. Thereafter, the intermediate film 3 is temporarily bonded to the cup 1 using a heat seal head 16. Temporarily adhere to the flange flat part 2 of cup 1.
The adhesive strength at this time must be strong enough to withstand the subsequent cutting process. Specifically, it depends on the adhesive width, but it is desirable to have a width of 0.2 kg/15 mm or more.

Next, the intermediate film is held on the pedestal 1 by the holding plate 26.
3, and the original fabric is cut from the cup by the saw blade 17.

Finally, the intermediate film 3 is permanently bonded by the heat-sealing head 22 from the flange flat part 2a of the cup 1 to its inner part 6.

The steps of temporary adhesion, cutting, and final adhesion are performed intermittently during the transportation of the cup.

In Examples 1 to 5 above, main adhesion may be performed by heat sealing once, but may be performed multiple times. Also, the flat part of the flange and the inner part thereof may be sealed separately using different heat sealing heads. In addition to cutting the intermediate film with a rotating blade or a saw blade, there are also methods using a blade that moves along the outer and inner contours of the area to be heat sealed, a hot plate, an impulse cutter, a burner, etc. Various methods can be applied, such as a method using fusing using a laser or the like.

(Effects of the Invention) According to the present invention, as for the cup, the intermediate film, and the lid, an easy-to-open heat seal is formed between the intermediate film and the cup, and a tight seal is formed between the intermediate film and the lid. In addition, the intermediate film and the cup are thermally bonded before filling the contents, and the intermediate film is thermally bonded to the lid after the contents are filled, and further,
By regulating the positions of the inner peripheral edge and the outer peripheral edge of each of the seal parts, a predetermined difference is provided between the peel strength from the center of the container and the peel strength from the outside of the container. , without compromising sealing reliability.
It can be opened easily by hand. Also,
It has become possible to prevent deterioration of heat sealing and sealing performance even if foreign matter enters the heat-sealed surface, maintain seal strength at 2.3Kg/15mm width or higher, and provide easy-open performance.

Further, according to the present invention, it has become possible to reliably and smoothly thermally bond the intermediate film to the portion of the cup to be sealed with the intermediate film accurately positioned.

[Brief explanation of the drawing]

FIGS. 1 and 2 are explanatory diagrams showing each step of the method of the present invention, in which A shows the step of thermally bonding the intermediate film, B shows the step of filling the contents, C shows the step of thermally bonding the lid, and FIG. FIG. 3 is a cross-sectional view showing the cross-sectional structure of the intermediate film suitably used in the present invention.
, FIG. 5, FIG. 6, FIG. 7, and FIG. 8 respectively represent Example 1, Example 2, Example 3, Example 4,
FIG. 7 is an explanatory diagram of an intermediate film thermal adhesion process in Example 5. 1 is the cup, 2 is the flange part (the part to be heat sealed),
3 is an intermediate film, 4 is an easily peelable seal, 5 is an outer peripheral edge, 6 is an inner peripheral edge, 7 is a content, 8 is an inner surface material, 9 is a lid, 10 is a tight seal, 13 is a cup receiver. 14 is the original fabric, 17 and 18 are blades, 16 and 22 are heat seal heads, and 19 and 20 are unnecessary parts, respectively.

Claims (1)

[Scope of Claims] 1. A step of thermally adhering an intermediate film having a surface whose adhesion to the cup is easily peelable to a portion of the single-layer or multilayer cup that is scheduled to be heat-sealed and includes at least the unsealing start position; filling the cup provided with the intermediate film with a content; applying a lid to the cup filled with the content, the lid having an inner surface layer capable of forming a tight seal with the intermediate film or further with the portion to be heat-sealed of the cup; It consists of a process of thermally bonding the cup and the lid in the area where the heat sealing is planned.
The inner edge of the sealing area between the intermediate film and the cup is the sealing area between the intermediate film and the lid inner layer. is located closer to the center of the container than the inner edge of the cup, and at the opening start position, the outer edge of the seal between the intermediate film and the cup is the outer edge of the seal between the intermediate film and the lid inner layer. A method for manufacturing an easy-to-open and sealed container, characterized in that the manufacturing method is performed so that the container is located closer to the center of the container. 2. Dimensions in which the inner peripheral edge of the intermediate film reaches above the cup side wall part that is closer to the center than the cup heat-sealing area, and the outer peripheral edge protrudes outward beyond the cup heat-sealing area. 2. The manufacturing method according to claim 1, wherein the intermediate film and the cup are bonded by heat. 3. Supply the intermediate film in the form of a continuous film to the part to be heat-sealed of the cup, heat bonding between the intermediate film and the part to be heat-sealed, and cut the intermediate film along the inner and outer contours. Claim 1, in which the unnecessary portion is separated, or the intermediate film on the portion to be heat-sealed of the cup is further thermally bonded to the cup.
Manufacturing method described in section. 4 Cut the continuous intermediate film along the inner circumference side contour to separate unnecessary parts, supply the separated intermediate film to the part of the cup to be heat-sealed, and connect the intermediate film and the part to be heat-sealed. Perform thermal bonding between the
2. The manufacturing method according to claim 1, wherein the intermediate film is then cut along the outer circumferential contour to separate unnecessary portions. 5 Cut a continuous intermediate film along the inner and outer contours, hold the cut circumferential intermediate film and apply it to the area of the cup to be heat sealed, and seal the intermediate film and the cup. 2. The manufacturing method according to claim 1, wherein thermal bonding is performed between the two. 6 A continuous intermediate film is supplied above the cup, this intermediate film is cut along the inner circumferential contour to separate unnecessary parts, and the separated intermediate film and the cup are bonded and the heat between them is removed. Perform gluing,
2. The manufacturing method according to claim 1, wherein the intermediate film is then cut along the outer circumferential contour to separate unnecessary portions. 7. Supply the intermediate film in the form of a continuous film only to the opening start part of the heat-sealing part of the cup and its vicinity, heat bonding between the intermediate film and the opening start part, and cut along the outer peripheral side contour. 2. The manufacturing method according to claim 1, further comprising performing thermal bonding between the intermediate film and the opening initiation portion.