JPH0530707B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to an easily openable sealed container.
More specifically, heat sealing after filling is performed under a relatively wide range of heat sealing conditions, the peel strength from the center of the container is high enough to withstand retort sterilization, and the container cannot be opened from the outside. The present invention relates to an easily openable sealed container having a heat-sealing structure that can be reliably and stably sealed 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 have been subjected to retort sterilization, the sealing strength of the heat-sealed part must be at least 2.3 kg/15mm width, and the sealing strength between the container body and lid must be When this value is reached, it becomes difficult to manually peel off the heat-sealed interface between the two. To solve this problem, Plastics, Vol. 38, No. 5, Page 65 (1987) provided a heat-sealable inner material layer on the entire inner surface of the container body, and In addition to providing an easily peelable seal between the two layers and a tight seal between the inner material layer and the lid, a score is provided to cut the inner material layer closer to the center than the heat-sealed part, and heat is applied from the center to the outside. A heat-sealed container has already been proposed that has a seal strength of 2.3 kg/15 mm or more and can be easily opened from the outside. Japanese Patent Application No. 62-121185 proposed by the present inventors discloses that an intermediate material is inserted between the flange and the lid of a cup-shaped container, and one side of the intermediate material has an easily peelable seal and the other side has an easily peelable seal. By forming a tight seal on the side of the container and locating the inner peripheral edge of the easily peelable seal part closer to the center of the container than the inner peripheral edge of the tight seal part, the peel strength from the center of the container can be reduced. It has been proposed to increase the peel strength from the outside. (Problems to be Solved by the Invention) Among the above-mentioned easy-to-open heat-sealed containers, the former is significant because it imparts easy-to-open properties to the package while maintaining sealing strength of 2.3 kg/15 mm or more. However, the problem is that there are restrictions on the structure and manufacture of the container, such as the need to perform score processing on the container. In addition, in order to score 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 expose the metal at the score area. To avoid this, it is necessary to make the resin layer inside the metal foil layer thicker. Furthermore, even if a metal foil layer is not included, in order to provide the above score, the area and thickness of the container flange inevitably increase, which increases the amount of container material used, increases the bulk of the package, and reduces the appearance characteristics. I don't like it either. On the other hand, in the case of the latter container, which forms a tight seal and an easily peelable seal through the aforementioned intermediate material, it has the advantage of not being subject to the above restrictions, but the seal strength varies depending on the heat sealing conditions. I still have the problem of doing so. For example, in the case of easily peelable seals, it is generally difficult to maintain a constant seal strength regardless of changes in heat seal temperature, and as the seal temperature increases, the seal strength tends to increase. In addition, in this heat seal structure, for example, heat sealing is performed in advance between the container flange and the intermediate material, and after the contents are filled into the container, heat sealing (filling seal) is performed between the intermediate material and the lid. This is necessary. In this case, the seal strength of the previously heat-sealed part (for example, easily peelable seal)
This results in the problem of being affected by subsequent heat sealing. In general, in the case of two-stage sealing via an intermediate material, it is preferable to use an easily peelable seal because heat sealing between the intermediate material and the flange can be operated with strict control of sealing conditions; ,
It is desirable that the seal between the intermediate material and the lid after filling with the contents be a tight seal, as it is necessary to ensure complete sealing even if foreign objects such as dripping contents exist at the sealing interface. . However, forming such a tight seal causes the resin layer of the inner lid material or the intermediate material to flow out to the outside, resulting in thinning of the lid.
At the same time, it tends to have a serious thermal effect on the easily peelable seal, and furthermore, it tends to cause problems in that the double seal structure is disturbed. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an easy-to-remove seal between an intermediate member and a container flange, and a tight seal between an intermediate member and a lid, in which the above-mentioned drawbacks are overcome and a tight seal is reliably and stably maintained between the intermediate member and the lid. An object of the present invention is to provide an openable sealed container and a method for manufacturing the same. Another object of the present invention is that the filling seal between the intermediate material and the lid is performed as a tight seal at a relatively low and wide temperature range, and as a result, the easy peeling formed between the intermediate material and the container flange is To provide an easily openable sealed container and a method for manufacturing the same, in which the influence of heat on the seal is significantly reduced, and leakage and thinning of the inner lid material and the intermediate material during filling and sealing are prevented. (Means for Solving the Problems) According to the present invention, a cup-shaped container having a heat-sealing flange, a lid having a resin inner surface material,
It has a laminated heat seal structure with a resin intermediate material inserted at least in the opening start part between the flange and the lid, and an easily peelable seal and a lid inner material and the resin intermediate material are provided between the flange and the intermediate material. A tight seal is formed between the lid inner material and the resin intermediate material, and at least one of the lid inner material and the resin intermediate material has a melting point lower than the melting point of the lid inner material and the resin intermediate material, whichever is lower, on the interface side between the two. Provided is an easily openable sealed container having a low-temperature sealing resin layer having a melting point, the inner edge of the easily peelable seal being located further inside the container than the inner edge of the tight seal. Ru. According to the present invention, the step of heat-sealing a resin intermediate material to the flange portion of a cup-shaped container having a heat-sealing flange to form an easily peelable seal, and after filling the container with contents,
The process consists of applying a lid having a resin inner surface material and heat-sealing the lid inner surface material and an intermediate material to form a tight seal. A material with a low-temperature sealing resin layer having a melting point lower than the lower of the melting point of the material and the melting point of the resin intermediate material is used to heat seal the intermediate material and the cup flange, and to seal the intermediate material and the lid inner material. heat seal,
The inner edge of the easy-to-open seal is positioned further inside the container than the inner edge of the tight seal, and the inner edge of the lid and the intermediate material are heat-sealed by heat conduction from the lid side. Provided is a method for manufacturing an easy-to-open sealed container. (Function) In the container of the present invention, an intermediate material is interposed between the flange and the lid at least at the opening start part, an easily peelable seal is provided between the flange and the intermediate material, and an easily peelable seal is provided between the lid inner material and the intermediate material. A tight seal is formed, but at least one of the lid inner material (A) and the intermediate material (B), and moreover on the interface side between the two, has a melting point of the lid inner material (M _A ) and the intermediate material (M _B ). A remarkable feature lies in the provision of a low-temperature sealing resin layer _C having a melting point (MC) lower than the lower melting point of the lower melting point. That is, the low-temperature sealing resin layer C used in the present invention
has a melting point that satisfies both the formulas M _C < M _A ... (1) and M _C < M _B ... (2), and as a matter of course, the low-temperature sealing resin layer C is on the inner surface of the lid. It must be able to be heat-sealed to material A as well as to intermediate resin B. When considering heat sealing between the intermediate material and the lid inner material, at least one of the two resins is melted by heating, and the two are pressed together to form a heat seal. Naturally, as both resins are heated, the easily peelable seal portion provided between the intermediate material and the flange is also heated due to heat conduction. In this case, when we actually measure the temperature rise over time at the interface between the intermediate material and the inner lid material, and the temperature rise over time at the interface between the intermediate material and the flange, we find that the former interface The rate of temperature increase at the latter interface is greater than that at the latter interface, and saturates at the melting point of the lower melting point of the two resins or at a temperature slightly higher than that (T _t ). There is a tendency to saturate at a certain corresponding temperature (T _p ) lower than this saturation temperature depending on the thermal conductivity or temperature gradient. In addition, when heating the intermediate material and the lid inner material,
Beyond the vicinity of each melting point, the lid inner surface material or the intermediate material flow, causing protrusion to the outside of the heat-sealed portion. Further, as the lid inner surface material or the intermediate material becomes thinner due to this protrusion, the thermal influence on the easily peelable seal portion becomes stronger. In the present invention, by interposing a low-temperature sealing resin layer having a melting point ( _M The saturation temperature (T _t ) can be set lower than the melting point (M _B ) of the intermediate material and the melting point (M B ) of the intermediate material, and the saturation temperature (T _{P )} of the easily peelable seal portion can be lowered accordingly. Therefore, it is possible to prevent thinning due to leakage of the inner lid material and intermediate material.
As a result, the influence of heat on the easily peelable seal portion during filling and sealing can be significantly reduced. It is also important to use a low-temperature sealing resin layer separately from the lid inner material and the resin intermediate material, and if the entire lid inner material is made of low-temperature sealing resin, the temperature should be slightly lower than the filling seal temperature at which a tight seal begins to form. When the temperature becomes high, the lid inner surface material flows and becomes thinner, and as a result, the influence of heat on the easily peelable seal portion increases. Furthermore, since the inner lid material has become fluid and thinner, peeling occurs between the inner lid material and the base material with a relatively small force when opening the package. Furthermore, when the entire resin intermediate material is made of a low-temperature sealing resin, the resin flows and becomes thinner during heat sealing, and the influence of heat on the easily peelable seal portion increases. According to the present invention, it is thus possible to completely heat-seal the container and the lid while also reliably achieving a tight seal and an easily peelable seal. Moreover, in the present invention, by performing heat sealing so that the inner edge of the easily peelable seal is located inside the container than the inner edge of the tight seal,
Since the peel force from inside the container acts on the tight seal portion, a large breaking strength corresponding to the peel strength of the tight seal portion can be obtained. Of course, when opening the package, the peelable seal portion can be peeled off to facilitate manual opening. (Preferred Embodiment of the Invention) In FIG. 2, which shows the easy-open sealed container of the present invention disassembled with each part to be heat-sealed, the sealed container is composed of a container body 1, a lid 2, and an intermediate material 3. Ru. The container body 1 has a heat-sealing flange 4, and the lid 2 is composed of a base material 5a and a resin inner material 5. In this specific example, the intermediate material 3 has a cohesive failure sealing resin layer 7 for forming an easily peelable seal portion between the intermediate material body 6 and the flange 4.
and a laminate of a low-temperature sealing resin layer 8. In FIG. 3 showing a state in which sealing is performed between each member of the container shown in FIG. A seal 9 is performed, and a tight seal 10 is performed between the lid 2 and the intermediate material 3 via a low-temperature sealing resin layer 8. The inner edge 11 of the easily peelable seal part 9 is located inside the container than the inner edge 12 of the tight seal part 10, and the outer edge 14 of the easily peelable seal part 9 is tight at the opening start position 13. Seal part 10
It is located inside the container than the outer edge 15 of the container, or is located at the same position as the outside edge 15 of the container. In FIG. 4, which shows a state in which a peeling force is applied from the inside to this sealing part, the inner edge 11 of the easily peelable sealing part 9 is closer to the inside of the container than the inner edge 12 of the tight sealing part 10. Therefore, a peeling force or breaking force P from the inside acts on the tight seal portion 10, and a large peeling or breaking strength of, for example, 2.3 kg/15 mm width or more is obtained. On the other hand, in FIG. 5, which shows a state in which a peeling force P' from the outside is applied to the opening start position 13 of the sealing part, when the end 17 of the lid 2 is grasped and pulled upward, the peeling force P' is concentrated on the outer edge 14 of the easily peelable seal portion 9, and opening by hand can be performed reliably and stably, and the peel strength from the outside is also reduced by 2.
Kg/15mm width or less easily removable seals can be used. In addition, the form of the container for reliably and stably opening the container is not limited to the form shown in Fig. 5, but also the form shown in Fig. 8, in which the intermediate material is used as a gripping part and protrudes together with the lid, and the form shown in Fig. 8, which is easy to peel. A configuration shown in FIG. 9 in which a score 18 for cutting the flange is cut on the outer surface of the flange inside the outer edge 14 of the seal is preferably applied. In FIG. 2, instead of providing the low-temperature sealing resin layer 8 on the intermediate material 3, a heat-sealing resin layer 8a may be provided on the inner lid material 5 as shown in FIG. 6, or as shown in FIG. Alternatively, the heat-sealing resin layers 8a and 8b may be provided on both the lid inner material 5 and the intermediate material 3. Incidentally, the cohesive failure sealing resin layer 7 is not necessarily necessary, and the point is that the intermediate material 3 and the flange 4
An easy-to-open seal within the range described above may be formed between the two. 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 have at least the inner surface made of an intermediate material and a resin having heat-sealing properties, such as, but not limited to, low-medium-high-density polyethylene, isotactic polypropylene, Olefin resins such as propylene-ethylene copolymers, ethylene-vinyl acetate copolymers, olefin resins graft-modified with ethylenically unsaturated carboxylic acids or their anhydrides; polyamides or copolymers with relatively low melting or softening points; Polyamide resin; polyester or copolyester resin having a relatively low melting point or softening point; polycarbonate resin, etc. 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, or tin 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, or biaxially oriented polyethylene terephthalate film. , a biaxially stretched nylon film, a thermoplastic resin film such as a polycarbonate film, various papers, or a laminate thereof as a base material, on which the heat-sealable resin layer A described above is laminated as an inner material.
The total thickness of the lid inner material is 25 to 25 mm.
100μm, especially those in the range of 30 to 80μm,
Commonly used. The intermediate material main body B is a film made of one or more layers of the heat-sealable resin described above, and its thickness must be at least strong enough to withstand the forces associated with opening, sterilization process, dropping impact, etc. Generally, a thickness in the range of 15 to 300 μm, particularly 30 to 100 μm is desirable. As already mentioned, the low-temperature sealing resin layer C has a melting point lower than the lower of the melting points of the resins A and B. In particular, when using a resin layer C having a melting point lower by at least 10° C. in relation to general heat sealing conditions that take into consideration the possibility of interfering sealing, etc., the effects of the present invention become remarkable. Resin layer C
The melting point of the resin can be adjusted by selecting the polymerization method or copolymerization method when producing the resin, or by selecting the amount of comonomer. Generally, the lower the density of a polymer, the lower the melting point, examples being high density polyethylene (HDPE) and low density polyethylene (LDPE). Additionally, a copolymer made by copolymerizing a certain amount of comonomer with a homopolymer has a lower melting point; an example of this is propylene-ethylene copolymer (PPE) compared to homopolypropylene (PP). . Furthermore, even if the copolymers are the same, a random copolymer has a lower melting point than a block copolymer; examples thereof include propylene-ethylene block B copolymer and random R copolymer.
Of course, the low-temperature sealing resin used in the present invention must satisfy the condition that it can form a tight seal. Examples of suitable inner material/low temperature sealing resin/intermediate material include, but are not limited to, the following. HPP or BPPE/R-PPE/HPP or BPPE,
HDPE or MDPE/LDPE, LLDPE, EVA,
EAA, IONOMER or EMA/HDPE or
MDPE; Here, MDPE is medium density polyethylene,
LLDPE stands for linear low density polyethylene, EVA stands for ethylene-vinyl acetate copolymer, EAA stands for ethylene-acrylic acid copolymer, and EMA stands for ethylene-methyl methacrylate copolymer. As a method for providing a low-temperature sealing resin layer on the inner lid material or intermediate material, there is generally a method of co-extruding a low-temperature sealing resin when forming the inner lid material or intermediate material, or a method of coextruding a low-temperature sealing resin layer on the inner lid material or intermediate material that has been formed in advance. A method of heat lamination or extrusion coating of a low-temperature sealing resin on the intermediate material is preferably applied. The low-temperature sealing resin layer should have a small thickness relative to the inner lid material, generally 1 to 50 μm,
In particular, 5 to 30 μm and 1/2 or less of the inner lid material,
In particular, it is preferable to have a thickness of 2/5 or less. As the cohesive failure sealing resin layer, for example, a blend of a plurality of resins is used, such as a blend of polypropylene resin with polyethylene and, if necessary, a rubber compatibilizer such as EPR. Of course, the heat seal structure in which an intermediate material is inserted in the present invention may be provided over the entire sealed portion between the container and the lid, but in the heat seal structure, once a certain length of peeling is performed, It should be understood that since subsequent peeling progresses relatively easily, it may be provided only at the portion of the sealing portion where peeling begins. Furthermore, it should be understood that the container in the present invention is not limited to a cup-shaped container, and that the present invention can also be applied to a bag-shaped sealed container, a so-called retort pouch. (Effects of the Invention) According to the present invention, at least one of the lid inner material and the resin intermediate material has a melting point lower than the lower of the melting point of the lid inner material and the resin intermediate material so as to be located on the interface side between the two. Furthermore, by providing a low-temperature sealing resin layer with a low melting point, an easy-to-open seal is created in which an easily peelable seal is maintained between the intermediate material and the container flange, and a tight seal is reliably and stably maintained between the intermediate material and the lid. A sealed container was provided. In addition, the filling seal between the intermediate material and the lid is performed as a tight seal at a relatively low temperature, and as a result, the thermal effect on the easily peelable seal formed between the intermediate material and the container flange is significantly reduced. Moreover, the leakage and thinning of the intermediate material caused by filling and sealing were also prevented. Furthermore, because we heat-sealed the inner edge of the easily peelable seal so that it was positioned further inside the container than the inner edge of the tight seal, the peeling force from inside the container would act on the tight seal. , a large breaking strength corresponding to the peel strength of the tight seal portion can be obtained. Of course, when opening the package, the peelable seal portion can be peeled off to facilitate manual opening. The invention is illustrated by the following example. (Example) On the aluminum side of the base material, a 12 μm biaxially stretched polyethylene terephthalate film and a 7 μm soft aluminum foil are laminated with a urethane adhesive, and a single or multilayer film is applied as a heat-sealable inner material using a urethane adhesive. A lid material shown in Table 1 was prepared. As 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 with a urethane adhesive, and then the 70 μm film side becomes the heat-sealing surface of this laminate. A circular container with a depth of 30 mm was prepared by deep drawing as described above and further formed with a heat sealing flange (outer diameter 75 mm, inner diameter 65 mm). As an intermediate material, a film shown in Table 2 having a cohesive failure sealing layer made of a propylene-ethylene random copolymer with an ethylene content of 4% blended with 35% by weight of linear low density polyethylene was prepared. The cup-shaped container, the lid material shown in Table 1, and Table 2
Using the intermediate materials shown in Table 3, sealed containers were produced using the combinations shown in Table 3 according to the following procedure. First, a circumferential film that can cover the heat-sealing flange surface of the cup-shaped container is cut from a raw film as an intermediate material, and the heat-sealing flange surface of the container and the cohesive failure sealing layer are heated at 180°C for 1.0 seconds. Thermal bonding (easily peelable seal) was performed under the following conditions. Six meatballs were filled in the container thus obtained, and a lid material to be applied to the container was heat-sealed. The heat sealing conditions during filling and sealing are a heat sealing time of 1.5 seconds and a heat sealing pressure of 100 kg.
And so. In addition, regarding the heat sealing temperature (temperature of the heat sealing head), determine in advance the temperature at which the seal strength between the intermediate material and the lid material becomes a tight seal after one heat sealing, in this case, the temperature at which the seal strength is 2.3 kg/15 mm width. , two conditions were set: this temperature and a temperature 10°C higher than this. Note that heat sealing was performed twice. The easily peelable seal part and the tight seal part were heat-sealed by regulating the shape and position of the heat-sealing head so that they were concentric with the outer diameter of the circular heat-sealing flange. At this time, the inner and outer diameters of the easily peelable seal portion were 66 mm and 73 mm, and the inner and outer diameters of the tight seal portion were 69 mm and 75 mm. Further, at the opening start part, the intermediate film was made to protrude together with the lid to serve as a grip part. The opening force (maximum opening strength at the initial stage of opening) and the sealing strength from the inside of the container (peel strength to breaking strength) of the sealed filled container obtained in this way were measured at 120°C -
After 30 minutes of retort sterilization, measurements were taken using a tensile tester. To measure opening strength, place the container in the crosshead.
Fix it at an angle of 45 degrees, and simultaneously hold the grip for opening the lid and intermediate material on the upper chuck (the angle between the top surface of the container and the grip is 45 degrees), 300 mm/
I pulled it up and down at a speed of 1 minute. Also, the seal strength is measured perpendicular to the direction of the heat seal.
Cut out a 15mm wide strip, and place the lid side of the strip into the upper chuck and the side wall side of the cup into the lower chuck.
It was pulled up and down at a speed of 300mm/min. Regarding the opening force, there was little variation in the values, so
Table 3 shows the average values. In addition, the ratio Pd of peeling between the aluminum foil of the lid and the inner material after opening, the ratio Pb of the lid breaking when opening,
Table 3 shows the percentage Ps where the seal strength was 2.3 kg/15 mm width or less. In Examples 2 to 7 where △T is sufficiently large, the opening force is
In addition to showing a value of around 2.0Kg, even if the heat sealing temperature was different by 10℃, the difference in opening force was as small as 0.1Kg. As a result, it was found that the heat sealing temperature may vary somewhat within a practical range. △T
When compared with Comparative Example 1, Example 1 in which the opening force was relatively small exhibited the effect of the present invention of reducing the opening force, but the effect against fluctuations in heat sealing temperature was weakened. On the other hand, in the comparative example, the opening force was high, and the difference due to the difference in heat sealing temperature was 0.2 to 0.4 kg, which showed a strong influence. Among them, lid material A is used, in which the lid inner material is made of a single block copolymer layer, and intermediate material L does not have a low-temperature sealing resin layer.
In Comparative Example 1 in which the sealant was used, the heat-sealing temperature had to be set high, and the opening force was the highest. In addition, there were cases where the lid material broke when the package was opened. This is thought to be due to the fact that the material strength of the lid material was insufficient due to the increased seal strength of the easily peelable seal portion and the thinner lid inner surface material. In addition, in Comparative Examples 2 and 3 in which the lid inner material was made of a single random copolymer layer, the lid material aluminum foil and the inner surface material were likely to separate,
Pd and Ps showed high values. When we observed the cross section of the seal, we found that the thickness of the inner lid material was 1/4
In addition to the following thinning, the intermediate material also became thinner. Intermediate material K whose main material layer is made of random copolymer
In Comparative Examples 4 and 5 using
The percentage Ps of 2.3Kg/15mm width or less was high. Definition of melting point In the present invention, melting point refers to heating rate conditions per minute.
Means the melting peak temperature obtained by differential scanning calorimetry (DSC) at 10°C. Furthermore, when the target resin is a blend, the melting peak temperature of the resin forming the matrix is taken as the melting point of the resin. Furthermore, when the same resin has two or more melting peak temperatures, the peak temperature with the widest melting peak area is taken as the melting point.

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[Table]

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【table】 [Brief explanation of drawings]

FIG. 1 is a diagram illustrating temperature changes during filling and sealing at the interface between the inner lid material and the intermediate material and the interface between the intermediate material cup, and FIG. 2, FIG. 6, and FIG. FIG. 3 is an exploded view of the removable sealed container into the lid material, the intermediate material, and the cup-shaped container;
The figure is a diagram illustrating a state in which the member shown in FIG. 2 is sealed, and FIG. 4 is a diagram illustrating a state in which a peeling force is applied from the inside to the sealed portion of the container shown in FIG. , FIG. 5 is a diagram illustrating a state in which an opening force is applied to the container, and FIGS. 8 and 9 are diagrams illustrating the form of the container applied to the present invention. Reference number 1 is the container body, 2 is the lid, 3 is the intermediate material,
4 is a heat sealing flange, 5a is a lid base material, 5
is the lid inner material, 6 is the intermediate material main body, 7 is the cohesive failure sealing layer, 8 is the low temperature sealing resin layer, 9 is the easily peelable sealing part, 10 is the tight sealing part, 13 is the opening start position, 17 is the opening 18 indicates a score for opening.

Claims (1)

[Scope of Claims] 1 Laminated heat sealing of a cup-shaped container having a heat-sealing flange, a lid having a resin inner surface material, and a resin intermediate material inserted at least at the opening start part between the flange and the lid. a structure, an easily peelable seal is formed between the flange and the intermediate material, and a tight seal is formed between the lid inner material and the resin intermediate material, and at least one of the lid inner material and the resin intermediate material, On the interface side between the two, there is a low-temperature sealing resin layer having a melting point lower than the lower of the melting point of the inner lid material and the melting point of the resin intermediate material, and the inner edge of the easily peelable seal is the same as that of the tight seal. An easily openable sealed container characterized by being located further inside the container than the inner edge. 2. A step of heat-sealing a resin intermediate material to the flange portion of a cup-shaped container having a heat-sealing flange to form an easily peelable seal, and after filling the container with contents, a lid having a resin inner material. and heat sealing the lid inner material and the intermediate material to form a tight seal, and as at least one of the lid inner material and the intermediate material, the melting point of the lid inner material and the resin intermediate material are added to the interface between the two. The material has a low-temperature sealing resin layer with a melting point lower than the lower of the melting points of The inner edge of the tight seal is positioned further inside the container than the inner edge of the tight seal, and the inner edge of the lid and the intermediate material are heat-sealed by heat conduction from the lid side. A method for manufacturing an easy-to-open sealed container.