JP5046098B2 - Easy-open lid member having functional resin layer and container sealed thereby and having functionality - Google Patents

Description

  The present invention relates to an easily openable lid member having a functional resin layer, and a container having a functionality in which the lid member is sealed by heat sealing, and more specifically, a consumer uses a lid member of a container in which food or the like is stored. An easy-opening lid member having a functional resin layer and a functionally easy-opening property that the functional material of the functional resin layer is not exposed when peeling and does not impair the flavor of stored foods, etc. It relates to the storage container.

Plastic containers have surpassed metal and glass containers in recent years due to their light weight, ease of molding, excellent physical properties and economy, and adaptability to environmental problems. It is widely used.
The slight disadvantage of plastic containers is that the amount of gas permeation through the walls of plastic containers is negligible because plastics have a very small gas permeability compared to metals and glass. Oxygen changes the contents of foods and the like, and oxygen promotes the growth of microorganisms that cause food spoilage in the container, which is a problem in terms of storage stability of foods. Furthermore, the flavor of food is impaired by the action of moisture, or dissipation due to vaporization of important components of pharmaceuticals is derived, and it is important to eliminate such problems in the technical field of plastic containers.

  For this purpose, various measures have been made to compensate for the disadvantages of the gas permeability of plastic containers. Recently, in order to prevent the permeation of gases such as oxygen through the walls of plastic containers, for example, the container walls have a multilayer structure. In order to suppress the intrusion of oxygen from the outside by using a resin having an oxygen shielding property such as an ethylene-vinyl alcohol copolymer for at least one layer, and to remove oxygen in the container, An oxygen-absorbing resin such as an oxygen scavenger is also used, and a method of absorbing oxygen in the container with the oxygen scavenger present in the container wall and keeping the container as oxygen-free as possible is heavily used. (For example, refer to Patent Document 1).

With the recent diversification of eating habits in the general society, the form of foods has also become diversified. As a result, various developments have been made in food packaging materials and containers. The demand for retort-molded containers for finished foods is very high.
In particular, retort-molded container foods are simple foods that contain cooked dishes, sealed and sterilized at high temperatures, and can be eaten immediately by consumers as they are or simply by heating. It has become mainstream in simple foods and is occupying a very important position in the field of plastic containers.

In such molded containers for instant foods and retort-processed molded containers for cooked foods, unlike containers for beverages, the container is not a cap, but a substantially flat lid member that seals the wide-mouth container is used for heat sealing. And sealed to the upper surface of the flange of the container opening.
In order to impart functionality such as oxygen gas absorption and shielding described in paragraph 0003 to the container, it is necessary to impart functionality to one or both of the molded container and the lid member. In a storage container such as food, since it is exclusively in contact with the gas in the upper space of the storage (atmosphere of the head space), it is more important from the viewpoint of the function (function) and efficacy (effect) of the functionality.

Therefore, conventionally, in such a lid member, a functional material such as an oxygen absorbent or a hygroscopic agent is contained in the inner layer portion, and the lid member mainly includes a heat seal layer, an oxygen absorbent-containing resin layer, and a gas barrier. The lid member that is composed of layers and has this functionality is tightly integrated with the upper surface of the flange portion of the container body by heat sealing (see, for example, Patent Documents 2 and 3).
However, in such a lid member, the melting point of the thermoplastic resin of the functional material compounding layer such as an oxygen absorbent is usually close to the melting point of the resin of the heat seal layer. When sealed and tightly integrated, the thermoplastic resin in the functional material blend layer is melted by the heat and pressure at the time of heat sealing, and is compatible or incompatible with the heat seal resin of the molten heat seal layer. In this state, functional materials such as oxygen absorbents are mixed into the heat seal layer, and resin pools are generated.
As a result, when the lid member is peeled off from the container body and the lid member is peeled off in order for the consumer to consume the storage container such as food, the resin of the heat seal layer undergoes interfacial peeling or cohesive fracture dissociation. In addition, a functional material such as an oxygen absorbent is exposed to the outside and adheres to the flange portion, or comes into contact with the stored food inside the container, resulting in a problem of impairing the flavor of the stored food. Reducing metal powders of oxygen absorbers and the like significantly impair the flavor (fragrance and taste), which is an important element of stored foods, and powders with a black color of reducing metal powders are not good for consumers. It also gives rise to a feeling of pleasure and damages the appearance of food.

Therefore, there is a strong demand in the field of functional resin containers to solve such problems in the lid member, and a method for solving the problem has already been proposed.
In the previous Patent Document 2, the melting point of the thermoplastic resin of the functional material blending layer such as an oxygen absorbent is set to be 10 ° C. or more higher than the melting point of the resin of the heat seal layer, and the oxygen scavenger is put on the flange portion of the container. Although it is not allowed to adhere, if the temperature is raised to 10 ° C. or higher, the heat and pressure at the time of heat sealing also melts the thermoplastic resin of the oxygen absorbent compound layer, and is compatible with the heat seal resin of the molten heat seal layer. Alternatively, mixing in an incompatible state cannot be sufficiently prevented.
On the other hand, if the melting point is considerably high, processability is generally deteriorated, dispersibility of an oxygen absorbent or the like is deteriorated, deterioration of the resin occurs, the odor is deteriorated, and the flavor of the contents is deteriorated. Further, the resin used causes a decrease in function due to a decrease in gas permeability. Therefore, in many cases, a thermoplastic resin of the functional material blending layer is a resin having a relatively low melting point such as polypropylene or polyethylene, but these are the same as the resin used for the heat seal layer, and 10 ° C. In order to secure the above melting point difference, the selection range of the resin is very limited.
In the previous Patent Document 3, using a heat seal layer made of an unstretched thermoplastic resin with high oxygen permeability, the layer thickness is 10 μm or more, and the lid member is peeled off inside the surface of the flange portion. Although the oxygen absorber is not exposed, it is difficult to sufficiently prevent the functional material such as the oxygen absorber from being exposed to the outside and adhering to the flange portion.

Japanese Examined Patent Publication No. 62-1824 (claim 1) JP 2001-121652 (Summary and paragraph 0017) JP 2003-335367 A (Abstract and paragraphs 0009, 0023)

As described in the background art paragraphs 0006 to 0007, it has functions such as oxygen absorption and moisture absorption, and is composed of a heat seal layer (easy-opening seal layer), a functional material-containing resin layer, and a gas barrier layer. The lid member is tightly integrated with the upper surface of the flange portion of the container body by heat sealing. In such a lid member, since the melting point of the thermoplastic resin of the functional material compounding layer such as the oxygen absorbent is close to the melting point of the resin of the heat seal layer, heat sealing is usually performed on the flange upper surface of the container body. If they are tightly integrated, the heat and pressure at the time of heat sealing will also melt the thermoplastic resin of the functional material compounding layer, which is compatible or incompatible with the heat sealing resin of the molten heat sealing layer As a result, functional materials such as oxygen absorbents are also mixed into the heat seal layer, or the thermoplastic resin in the functional material blending layer is pushed out to form a resin pool. As a result, when the lid member is peeled off from the container body by the fingertip so that the consumer can consume the storage container for food or the like, the functional material such as the oxygen absorbent is exposed to the outside when the lid member is peeled off. The problem which adheres to a part or impairs the flavor of the foodstuff stored inside a container will arise.
And in the field of functional synthetic resin container lid members, a solution to such a problem has already been proposed, but the present situation is that a sufficient solution has not yet been obtained.

  In view of such a situation, when the lid member that has been heat-sealed is peeled off from the container body and the lid member is peeled off, the functional material such as an oxygen absorbent is exposed to the outside and the flange portion of the container is exposed. It is an object of the present invention to sufficiently prevent the phenomenon of adhering or impairing the appearance and flavor of the stored food inside the container by a simple means.

In order to solve the above-mentioned problems, the inventors of the present invention have a flange member in which a main part is composed of a heat seal layer (easy-opening seal layer), a functional material-containing resin layer, and a gas barrier layer. Conditions for heat sealing to the upper surface and the compatibility and melting point of the heat sealing resin and the functional material compounded resin, or the selection of the resin material of each layer and the layer thickness of each layer, as well as the peeling phenomenon in the heat seal layer, etc. An experimental examination was conducted after considering and taking into account.
In that process, the thermoplastic resin of the functional material compound layer is also melted by the heat and pressure at the time of heat sealing, and mixed with the heat seal resin of the molten heat seal layer in a compatible or incompatible state. To suppress this, simply increasing the melting point of the thermoplastic resin in the functional material-containing layer will cause deterioration of the resin, deterioration of the function and deterioration of the flavor. A thermoplastic resin layer having a higher melting point is interposed between the heat seal layer and the functional resin layer, and in particular, a temperature difference in melting point with respect to both the thermoplastic resin of the heat seal layer and the functional resin layer. When the temperature is set to 30 ° C. or higher, the inventors have found that the above problems can be solved easily and effectively, and have created the present invention.

  Thus, the basic requirement of the present invention is formed by a laminated film material provided with at least a barrier layer, a functional resin layer, and a heat seal layer, and the melting point between the functional resin layer and the heat seal layer, in particular, both layers. An easily openable lid member having a functional resin layer, wherein a high melting point resin layer having a difference of 30 ° C. or more is provided.

As a more specific embodiment, the lid member further has a base material layer. This base material layer is a heat resistant resin, and printing is performed on the inner surface or the outer surface as necessary.
As the barrier layer, a metal foil layer, a film having a metal vapor deposition layer or an inorganic oxide vapor deposition layer on one or both sides, or an ethylene-vinyl alcohol copolymer or polyvinylidene chloride as an oxygen shielding resin layer is used. .
As the functional resin layer, a polyolefin resin is used as a synthetic resin in which a functional material is blended.
The heat seal layer varies depending on the resin in the heat seal part on the molding container side, but is required to be a thermoplastic resin, and among them, a polyolefin-based resin is preferably used.
The function of the functional resin layer is preferably any of oxygen absorbability, moisture absorbability, odor absorbability, and various gas absorbabilities. In the functional resin layer, preferably, the oxygen absorption is by a reducing metal material or a self-oxidizing synthetic resin, the water absorption is by zeolite, the odor absorption and various gas absorptions are by high silica type zeolite, Each functionality is demonstrated. These functional materials are dispersed and used in the synthetic resin of the functional resin layer.

As an incidental invention, an easily openable lid having a functional resin layer in a flange portion of a container having a flange portion formed of a laminate having at least a barrier layer and having an upper surface of the flange portion having heat sealability The member is heat-sealed and integrated, and an easy-open container having the functionality sealed by the above-described easy-open lid member can be used.
Even if the upper surface of the flange portion is flat, it is sealed without any problem and good easy-openability and sealing performance can be obtained. However, a protruding portion may be provided on the entire upper surface of the flange portion. It is easier to adjust the seal strength and provide higher adhesive strength and easier opening by providing a heat seal protrusion (also called a protrusion or protrusion) on the flange surface of the opening of the container and heat sealing the lid member on the upper surface. Properties, sealing properties, and resistance to biting and sealing can be obtained.
In addition, a resin reservoir is formed inside the protrusion on the upper surface of the flange portion, and the resin reservoir is covered with a heat-sealable resin to increase the peel strength of the lid member.

  Further, incidentally, a flange portion may be provided in the heat seal portion of the flange surface, and a peeling tab allowance portion may be provided in the lid member. As a preferred application mode, food is stored in the container and is subjected to retort sterilization. Has been processed.

By the way, the present invention is basically a laminated film material having at least a barrier layer, a functional resin layer, and a heat seal layer, and in particular, between the functional resin layer and the heat seal layer, in particular, the functional resin layer and the heat seal layer. An easily openable lid member having a functional resin layer, wherein a high melting point resin layer having a melting point difference from the resin forming the layer of 30 ° C. or more is provided.
With this configuration, when the heat-sealed lid member is peeled off from the container body and the lid member is peeled off, a functional material such as an oxygen absorbent is exposed to the outside and adheres to the flange portion of the container, or inside the container. Although it has become possible to sufficiently suppress the phenomenon that impairs the appearance and flavor of the stored food by simple means, such a configuration and its effect are not described in the above Patent Documents 1 to 3. They cannot be found even if other related patent documents are scrutinized.
In addition, Patent Document 2 describes that another thermoplastic resin layer may be interposed between the functional resin layer and the easy-open seal layer (paragraph 0011). There is no description of the melting point or the function thereof, and it does not suggest the present invention.

In the above, the present invention has been generally described as means for solving the problems along the basic configuration and features of the present invention.
Here, when overviewing the present invention as a whole, the present invention is composed of the following invention unit group, and the invention of [1] is a basic invention, and the inventions below that embody or embody the basic invention. The embodiment is to be realized. (The invention group as a whole is collectively referred to as “the present invention”.)

[1] Functionality formed by a laminated film material provided with at least a barrier layer , a functional resin layer having oxygen absorbability, moisture absorbability, odor absorbability, and various gas absorbability functions and a heat seal layer. A functional resin layer, wherein a high melting point resin layer having a melting point higher by 30 ° C. or more than the melting point of the resin forming the functional resin layer and the heat seal layer is provided between the resin layer and the heat seal layer. An easily openable lid member.
[2] In the functional resin layer, the oxygen absorption is reduced by a reducing metal material or a self-oxidizing synthetic resin, the moisture absorption is by zeolite, the odor absorption and various gas absorptions are by high silica type zeolite, The easy-open lid member having the functional resin layer according to [1], wherein the functionality is made.
[3] In a flange portion of a container that is formed of a laminate having at least a barrier layer and has a flange portion, and the upper surface of the flange portion has heat sealability, the functional resin layer in [1] or [2] An easy-open container having functionality and sealed by an easy-open lid member, wherein the openable lid member is heat-sealed and integrated.
[4] A projecting part is provided on the entire upper surface of the flange part. The easy-opening container having functionality sealed in [3] by an easy-opening lid member.
[5] The easy-open container having functionality, sealed with an easy-open lid member in [3] or [4], wherein the food is stored in the container and retort sterilized.

  In the present invention, it has functionalities such as oxygen absorption and moisture absorption, is composed of a heat seal layer, a functional material-containing resin layer, and a gas barrier layer, and is tightly integrated with the upper surface of the flange portion of the container body by heat seal. In the lid member, when the consumer peels off the heat-sealed lid member from the container body and peels off the lid member, the functional material such as an oxygen absorbent is exposed to the outside and the flange portion of the container It is possible to sufficiently suppress the phenomenon of adhering to the surface or impairing the appearance and flavor of the stored food inside the container by simple means.

  The present invention has been described in accordance with the basic configuration of the present invention as a means for solving the problems, but in the following, embodiments of the invention of the present invention group described above will be described with reference to the drawings. The details will be described in detail.

1. Easy-open lid member having a functional resin layer (1) Functional lid member Generally, a functional lid member is a plastic molded container, particularly the top surface of the mouth of a functional multilayer molded container. It is a member that is sealed by means of heat sealing at the part, and is usually cut according to the shape of the mouth of the container after heat-sealing the laminated sheet material to the flange part.
The schematic perspective view is illustrated in FIG. 1, and the functional lid member (12) is hermetically integrated with the multilayer molded container (11). Preferably, the consumer peels off the lid member at the end of the lid member. The knob part (13) for this is formed as a protrusion piece.

(2) Functionality of the lid member The functionality of the lid member is any of oxygen absorbability, moisture absorbability, odor absorbability, various gas absorbabilities, and the like conventionally employed. A plurality of these functions may be provided, and this can be achieved by using a functional material having a plurality of functions or using a multilayer functional material layer.

a. Oxygen-absorbing function Oxygen-absorbing function is, for example, the ability of oxygen to chemically change the contents of food and the like, and oxygen promotes the growth of microorganisms that cause food spoilage in the container. This is a function to prevent oxygen from being damaged, and absorbs oxygen in the container, particularly oxygen in a space (head space) above the stored item in the container to keep the container as oxygen-free as possible.
As the oxygen-absorbing functional material, a normal reducing metal material or a self-oxidizing synthetic resin is mainly used.

As the reducing metal material, an iron-based oxygen scavenger excellent in oxygen absorption and economy is typically used. The iron-based oxygen absorber provides a strong oxygen absorbing action due to its excellent reducibility (deoxygenation from surrounding substances).
In addition, as an iron-type oxygen absorber, what was conventionally used for this kind of application can be used, for example, reducing iron, ferrous oxide, iron tetroxide, iron carbide, silicon iron , Iron carbonyl, iron hydroxide and the like. These can be used singly or in combination of two or more.

The normal particle size and density are also suitable. If a material having an excessively large average particle size is used, fish eyes and the like may be generated during forming into a multilayer sheet, and the appearance of the lid member may be impaired. Usually, the particle size is preferably about 1 to 100 μm, and the shape is spherical, flat, etc., and the flat shape is particularly desirable from the viewpoint of adhesion between the oxygen absorbing layer and the adjacent layer.
In general, the iron-based oxygen scavenger is preferably 1 to 200% by weight, particularly 10 to 100% by weight per resin. If the amount of the iron-based oxygen scavenger is lower than the above range, it will be difficult to control the oxygen concentration in the container below the concentration suitable for the growth of microorganisms. Not only is there no particular effect in terms of concentration reduction, but there is a tendency to be disadvantageous in terms of formability and price.

Examples of other reducing metal-based materials include reducing zinc and reducing tin powder.
If necessary, a metal halide, a hydroxide of an alkali metal or an alkaline earth metal, or the like can be used in combination with the reducing metal material as a reduction reaction promoter.

  As the self-oxidizing synthetic resin, a normal self-oxidizing polyolefin resin is used. Specifically, for example, an oxygen-absorbing resin composition comprising a thermoplastic resin having an ethylene structure in a molecular structure, a transition metal catalyst, and a trigger styrene-based resin described in JP-A-2006-176755 (abstract) Things.

b. Moisture absorption function Moisture (moisture) absorption function is adopted, for example, to prevent food from becoming wet and its flavor from being damaged by the action of moisture. This function is, for example, silica gel, which is a normal desiccant. Although it is made of calcium chloride or the like, zeolite fine powder is preferably used.

The hygroscopic agent preferably has an average particle size of 5 to 70 μm. If the particle size is smaller than 5 μm, aggregation tends to occur and secondary particles having a large diameter are formed, the surface area becomes smaller and the hygroscopic property becomes worse. Since it becomes small and the hygroscopic action becomes small, it is not preferable.
The blending amount of the hygroscopic agent is 0.1 to 90% by weight, particularly preferably 0.1 to 60% by weight, based on the resin material. If it exceeds 1, the hygroscopicity is too large and foaming is liable to occur, and the roughness of the film increases, which is not preferable.

c. Odor absorption function (and gas absorption function)
The odor absorbing function, for example, removes odor (gas) that adversely affects the flavor of stored food, activated carbon, metal oxide, metal salt, metal, green tea component, chlorophyll, flavonoid, phytoncide, silica gel, zeolite Etc. are used.
Preferably, a high silica type zeolite containing an alkali metal or the like as an exchange cation described in JP-A-2006-28496 (summary) is used, for example, generated from the inside of a storage container or containing an oxygen absorbent It supplements odors such as ketones, aldehydes and alcohols, which are oxidation by-products from the resin layer.
As the high silica type zeolite, ZSM-5 type zeolite is particularly preferable. Further, if the high silica type zeolite has a cage-like structure in which fine particles are aggregated, the adsorption surface area increases, and it effectively acts on an organic compound having a size larger than expected from a simple zeolite pore.
The zeolite preferably has an average particle size of 0.5 to 10 μm. The content in the thermoplastic resin is preferably 0.1 to 50% by weight, and more preferably 0.5 to 25% by weight.

When a polyester resin is used as the laminated material, a trace amount of aldehydes generated by hydrolysis or thermal decomposition during polymerization or molding of the polyester resin impairs the flavor of the stored food. Therefore, a metaxylylene group-containing polyamide (so-called Aldehyde reducing agents such as MXD6-nylon) may be used.
As described above, the odor absorbing function can be said to be a gas absorbing function other than oxygen and moisture.

(3) Laminated structure of functional lid member a. Layer structure As shown in the laminated cross-sectional structure diagram of FIG. 2, the conventional lid member has a base material layer (24), a barrier layer (23), a functional resin layer (22), It is comprised by the heat seal layer (21).
On the other hand, the lid member having functionality in the present invention is, as illustrated in the laminated sectional structure diagram of FIG. 3, from the top, the base material layer (35), the barrier layer (34), and the functional resin layer (33). , A high melting point resin layer (32), and a heat seal layer (31).
The thickness of the base material layer is about 3 to 50 μm as a thickness necessary for fulfilling the strength as the base material to be printed or the like or the function as the metal protective layer.
The thickness of the barrier layer varies greatly depending on the aspect such as the vapor deposition layer, the aluminum foil, and the barrier resin, and is appropriately set from the range of 0.005 to 50 μm.
The thickness of the functional resin layer is about 5 to 100 μm as a thickness that satisfies the functional requirements required for the container and takes into consideration suitability as a lid.
The thickness of the high-melting point resin layer is about 5 to 50 μm as a thickness necessary for separating the heat-seal layer and the functional resin layer and performing a function required when the lid member is peeled off.
The thickness of the heat seal layer is determined from the thickness that can be easily opened and heat sealed, and is about 5 to 100 μm.

b. Difference in action due to layer structure As described in paragraph 0009, the lid member having conventional functionality has functionalities such as oxygen absorbability and moisture absorbability, and a heat seal layer (easy-open seal layer) and The lid member having the functional material-containing resin layer and the gas barrier layer is closely integrated with the upper surface of the flange portion of the container body by heat sealing. In such a lid member, since the melting point of the thermoplastic resin of the functional material compounding layer such as the oxygen absorbent is close to the melting point of the resin of the heat seal layer, heat sealing is usually performed on the flange upper surface of the container body. If they are tightly integrated, the heat and pressure at the time of heat sealing will also melt the thermoplastic resin of the functional material compounding layer, which is compatible or incompatible with the heat sealing resin of the molten heat sealing layer As a result, functional materials such as oxygen absorbers are also mixed into the heat seal layer. Therefore, in order for consumers to consume storage containers such as food, when the lid member is peeled off from the container body with a fingertip and the lid member is peeled off, the interface seal or cohesive peeling is performed, the oxygen absorbent from the heat seal layer, etc. The functional material is exposed to the outside, and the functional material adheres to the flange portion or comes into contact with the stored food inside the container, resulting in a problem of impairing the appearance and flavor of the stored food.

On the other hand, the functional lid member according to the present invention is provided between the functional resin layer (33) and the heat seal layer (easy-opening seal layer) (31) as illustrated in the laminated sectional view of FIG. In particular, a high-melting point resin layer (32) having a melting point difference of 30 ° C. or more with the functional resin layer and the heat seal layer is formed. Even if the thermoplastic resin of the resin layer is melted, this layer is mixed with the heat seal resin of the melted heat seal layer in a compatible or incompatible state, and a functional material such as an oxygen absorbent is used in the heat seal layer. It can be sufficiently prevented from getting mixed in.
Therefore, when the consumer peels off the heat-sealed lid member from the container body and peels off the lid member, a functional material such as an oxygen absorbent is exposed to the outside and adheres to the flange portion of the container. It is possible to sufficiently prevent a phenomenon that comes into contact with the stored food and damages the appearance and flavor of the stored food by a simple means.

c. Material structure of each layer The material structure of each layer in the easy-open lid member having the functional resin layer of the present invention is not particularly limited, but basically, the base material layer is a heat-resistant resin, and the barrier layer is A metal foil, a film having a metal vapor-deposited layer or an inorganic oxide vapor-deposited layer on one or both sides, or an oxygen shielding resin, the synthetic resin of the functional resin layer is a polyolefin resin, and the high melting point resin layer is a polypropylene resin Or a polyamide resin or a polyester resin, and the easy-open sealing layer is a polyolefin resin.

  A base material layer is a layer which mainly bears the mechanical strength and heat resistance from the outside in a lid member, or plays the role of a protective layer of metal foil. Specifically, as the thermoplastic resin of the base material layer, a polyester resin and a polyamide resin are suitable, and a polypropylene resin is also used. These resins are excellent in mechanical properties such as impact resistance and chemical properties such as chemical resistance, have excellent moldability and economy, and are preferably used as a thermoplastic resin for the outer layer. Moreover, as a protective layer of metal foil, the heat resistant resin used as a coating material is preferable.

  Specifically, examples of the polyester film include polyethylene terephthalate, polybutylene terephthalate, and polynaphthalene phthalate, examples of the polyamide film include nylon 6, nylon 6, 6, and the like, examples of the polyolefin film include polypropylene, polyethylene, and the like. Tactic polypropylene, ethylene-propylene copolymer, propylene-butene-1 copolymer, and blends thereof are used. In addition, as the protective layer of the metal foil, various polyesters, epoxy resins, urea resins, melamine resins or combinations thereof used as paints are used.

The barrier layer is a layer for preventing oxygen gas and moisture from entering the container from the outside, and a metal foil, an inorganic material vapor deposition film, and an oxygen blocking resin are used.
More specifically, as the metal foil, for example, an aluminum foil, an iron foil, a copper foil, and a metal foil such as nickel or titanium are used.
Further, a thermoplastic resin film provided with a metal vapor deposition layer on one side or both sides thereof is used, and the base film is polyethylene terephthalate, polybutylene terephthalate, polynaphthalene phthalate, polyamide, nylon 6, nylon 6, 6, polypropylene. Polyethylene, and may be uniaxially or biaxially stretched. For example, aluminum vapor deposition is performed on one side of these thermoplastic resin base films. As a metal to be deposited, metals such as copper, titanium, tin, etc. can be used in addition to aluminum. More preferably, there is a coat layer for improving adhesion between the vapor deposition layer and the thermoplastic resin.
Moreover, the thermoplastic resin film which provided the inorganic oxide vapor deposition layer on the single side | surface or both surfaces is also used. The same film as described above is suitable for the substrate. As the oxide for depositing the inorganic oxide, one or more of alumina, silicon oxide, titanium oxide, tin oxide and the like are used.

Examples of the oxygen shielding resin for the barrier layer include an ethylene-vinyl alcohol copolymer, polyvinyl chloride, polyvinylidene chloride, and a polyamide-based resin that have high gas shielding properties. Among these, an ethylene-vinyl alcohol copolymer is preferably used because of its excellent oxygen shielding properties. Specifically, an ethylene-vinyl acetate copolymer has a saponification degree of 96 mol% or more, particularly 99. A saponified copolymer obtained by saponification so as to be at least mol% is used. Examples of the polyamide-based resin include a nylon multilayer film including at least one layer of an ethylene-vinyl alcohol copolymer, a nylon multilayer film including at least one layer of MXD6 and a layer thereof, a polyvinylidene chloride film, and a polyacrylonitrile film. .
The examples given as these barrier layers may be used alone, or two or more of them may be used in combination.

As the resin for the functional resin layer, a polyolefin-based resin having a certain degree of gas permeability for absorbing gas such as oxygen inside the container is preferably used.
Specifically, ultra-low-, low-, medium-, and high-density polyethylene, linear low-density polyethylene, isotactic polypropylene, propylene / ethylene copolymer, polybutene-1, and ethylene / propylene copolymer , Ethylene / butene-1 copolymer, propylene / butene-1 copolymer, ethylene / vinyl acetate copolymer, ion-crosslinked olefin copolymer (ionomer), poly-4-methylpentene-1, maleic anhydride modified polypropylene And maleic anhydride-modified polyethylene, ethylene-methacrylic acid copolymer, ethylene-acrylic acid copolymer, ethylene propylene rubber (EPR), ethylene propylene diene rubber (EPDM), and the like.
Moreover, the multilayer structure which added thermoplastic resin layers, such as a cushion layer, between the functional resin layer and the barrier layer may be sufficient. Examples of the thermoplastic resin include polyolefin, polyester, and polyamide resin, which may be uniaxially or biaxially stretched.

  Polyolefin having a certain degree of gas permeability for absorbing gas such as oxygen inside the container as a high melting point resin having a melting point difference of 30 ° C. or more with the resin of the high melting point resin layer, particularly the functional resin and the heat seal layer Resin such as polypropylene resin, poly-4-methylpentene-1, high density polyethylene, and linear low density polyethylene are used, and polyamide resins and polyester resins, particularly stretched resins thereof are also preferably used because of their high melting point function. Is done. Examples of the polyamide resin include nylon 6, nylon 6,6 and copolymers thereof, MXD6, and examples of the polyester resin include polyethylene terephthalate (PET), polybutylene phthalate (PBT), and polynaphthalene phthalate (PEN).

In addition, engineering plastics can be used as a high melting point resin. Specific examples include polysulfone, cycloolefin polymer, cycloolefin copolymer, polyimide, polycarbonate, polyphenylene sulfide (PPS), and polyetherimide, which may be uniaxially or biaxially stretched.
Moreover, although these films may be a single layer, one or more resins may be used to further combine with an adhesive layer to form a multilayer. The adhesive layer is selected and used depending on modified polyethylene, modified polypropylene, polyester, epoxy resin, tackifier resin, and other appropriate resin configurations.
Of these, polyamide resins and polyester resins are particularly suitable. These resins have a high gas barrier property under normal use conditions, and there is a risk that the oxygen (and odor components) in the headspace will not reach the functional resin layer. Since the permeability increases, the function of the functional resin layer is greatly exerted. Furthermore, after that, the barrier property is lowered by moisture from the contents in the distribution process, and the oxygen permeability is maintained, so that its function is sufficiently maintained.

Various heat-sealable resins are used as the resin for the heat seal layer. Polyolefin resins, particularly polyethylene resins and polypropylene resins, have gas permeability, easy heat seal properties, and easy peeling (easy). Peelability: easy opening) is also preferable.
Specifically, as with the resin of the functional resin layer, low-, medium-, and high-density polyethylene, linear low density polyethylene, isotactic polypropylene, propylene / ethylene copolymer, polybutene-1, Ethylene / propylene copolymer, ethylene / butene-1 copolymer, propylene / butene-1 copolymer, ethylene / vinyl acetate copolymer, ion-crosslinked olefin copolymer (ionomer), poly-4-methylpentene-1 , Maleic anhydride modified polypropylene, maleic anhydride modified polyethylene, ethylene-methacrylic acid copolymer, ethylene-acrylic acid copolymer, and other thermoplastic elastomers of ethylene propylene rubber (EPR) and ethylene propylene diene rubber (EPDM) These may be used alone or as a mixture. Such as those used is exemplified.
Moreover, you may form an easy-peelable heat seal layer as a multilayer which combined the resin layer which used the said resin individually or in mixture of 2 or more types.

In addition, the resin constituting the base material layer, the barrier resin layer, the functional resin layer, the heat seal layer, and the resin of the intermediate layer of these layers provided as necessary include coloring pigments such as titanium oxide, mica, You may add well-known additives, such as fillers, such as a silica, clay, and calcium carbonate, antioxidant, a slip agent, and an ultraviolet-ray inhibitor.
An adhesive layer may be provided between the above-described layers as necessary. As the adhesive layer, a modified polyolefin resin, such as maleic anhydride-modified polypropylene, maleic anhydride-modified polyethylene, maleic anhydride-modified polystyrene, ethylene-acrylic acid copolymer, ionomer, other resins such as polyurethane, epoxy, polyester, etc. You may use it in combination with a hardening | curing agent.

2. Container Body The container body sealed by the easy-open lid member of the present invention is a container having at least one barrier layer. Since the easy-opening lid member has an easy-to-open property having a functional resin layer, the container body member is required to have a barrier property that blocks the outside air and contents, and functions to demonstrate functionality in cooperation with the lid member. May have a functional resin layer. It is also necessary to have heat sealability. For example, molded containers in which ethylene-vinyl alcohol copolymer, polyvinylidene chloride, MXD6 nylon is used as a barrier layer, polyolefin resin such as polypropylene is used as a heat seal layer and an outer layer, and an adhesive layer is provided therebetween, aluminum foil and iron foil inside and outside A specific example is a molded container in which a polyolefin film such as a polypropylene film is laminated on a layer, molded into a cup shape, and further formed with a flange.

(1) Container structure The outline of the container structure is schematically illustrated in FIG. 1. The container structure is formed of a laminate having at least a barrier layer, has a flange portion, and the upper surface of the flange portion has heat sealability. In the flange part of the container, an easily openable lid member having a functional resin layer is heat-sealed and integrated.

(2) Layer configuration The container is basically composed of a laminate composed of at least a barrier layer and a heat seal layer. Usually, an outer layer is provided for the same purpose as the base material layer of the lid member, and a functional resin layer may be included in the laminate in order to further improve the functionality of the container. Similar to the lid member, an adhesive layer may be provided between the layers as necessary.
The outer layer resin is the same resin as the lid member resin described in paragraph 0036, and the functional resin layer resin is the same resin as the lid member resin described in paragraph 0040. The resin described in paragraph 0043 is also used for the heat seal layer. The material described in paragraph 0038 is also used for the barrier layer. The resin described in paragraph 0044 is also used for the adhesive layer.
Similarly to the lid member, the resin constituting each of the above layers includes a coloring pigment such as titanium oxide, a filler such as mica, silica, clay and calcium carbonate, an antioxidant, a slip agent, and an ultraviolet ray inhibitor. It may be added.
Specific examples of the layer configuration are illustrated in FIG. 4 as an outer layer (41), a barrier layer (42), a functional resin layer (43), and a heat sealable resin layer (44) in the flange portion.

(3) Other features In order to narrow the heat seal width or to form a resin reservoir, as illustrated in FIG. 4 as a cross-sectional view of the flange portion of the container, A heat seal protrusion (45) is provided, and a heat sealable lid member is heat sealed to the protrusion to seal the container.
The size of the projecting portion can be set as appropriate, but is preferably about 0.5 to 5 mm together with the height and width in terms of easy adjustment of heat sealability.

Further, inside the protruding portion on the upper surface of the flange portion, as illustrated in FIG. 5 as a cross-sectional view of the heat seal portion, a resin reservoir (52) is preferably formed in the flange portion (51), and the resin The pool is covered with the heat-sealable resin (53), and the peel strength of the lid member is increased. (54) shows a base material layer and a functional resin layer in the lid member.
In FIG. 5, a part of the thermoplastic resin in the flange portion is melted by heat and pressure during heat sealing, and a resin reservoir is formed at the seal end portion, preferably on the inner side of the container. The resin is covered so as to cover the resin reservoir. Therefore, even if the high temperature and high pressure gas inside the container during retorting causes a peeling action to the outside of the container, the resin reservoir and the covering seal resin layer resist the peeling action, and the sealing performance of the lid member (Adhesive strength) can be fully expressed.
When the lid member is peeled off by the consumer, the lid member is peeled from the outside, so that the adhesive strength does not function and does not hinder easy peelability.

Further, as an optional member, an easy-peeling allowance portion may be provided in the mouth portion and the lid member in the flange portion of the container.
Specifically, as illustrated in FIG. 6 as a cross-sectional plan view of the container opening, the lid member (64) joined to the heat seal part (63) of the flange surface (62) of the container opening (61). In FIG. 5, a peeling tab portion (66) is formed at a position of the mouth opening (65) provided in the container opening. When the consumer peels and removes the lid member, if the picking margin part is picked up and peeled off by the fingertip, easy peelability is improved by the principle of leverage.

3. Easy opening of container lids In general, retort food is prepared by storing cooked food in a container and sealing and bonding the lid material by heat sealing or the like, followed by retort sterilization (usually about 120 to 130 ° C. for 10 to 30 minutes. In this case, high pressure is likely to be generated from the inside of the container, and there is a risk of hot water entering from the outside. On the other hand, when a consumer eats retort food, it is necessary to be able to peel off the lid member with just the fingertips with as little force as possible, and as low an adhesive strength as possible is required at the adhesive sealing portion of the lid member. It is done.
Generally, in retort sterilization treatment, an adhesive strength of about 2.3 kg / 15 mm width or more is required, and for easy opening at the time of consumption, an adhesive strength of about 1.5 kg / 15 mm width or less is required.
In a retort container, there is a severe requirement that conflicts with the adhesive sealing portion of the lid member, and adjustment thereof is important.
In the present invention, the conflicting requirements described above are provided by providing the heat-seal protrusions or resin reservoirs as described above in paragraphs 0048 to 0050, and further, the separation member for peeling off the lid member in the heat-seal part. Is adjusted.

4). Production of Lid Member and Container Main Body The multilayer sheet material used for the lid member and container main body in the present invention can be produced by a method known per se.
For example, it can be obtained by melt-kneading these resin raw materials with an extruder corresponding to each resin layer, and then simultaneously melt-extruding the resin raw material into a predetermined sheet body through a multilayer multiple die such as a T-die or a circular die. It can also be obtained by co-injection or sequential injection into an injection mold after melt-kneading with an injection molding machine corresponding to each resin layer. Furthermore, various lamination methods and lamination molding using an adhesive may be used.

  Molding into a container using a multilayer sheet material is performed by ordinary vacuum forming, pressure forming, or the like, more preferably deep drawing. In this case, the molding temperature varies depending on the melting point or softening point of the resin to be used, but is generally preferably in the range of 165 to 170 ° C.

  The method of heat-sealing the lid member to the flange portion of the container is also performed by a known method using a heat-seal bar or the like, and the heat-sealing conditions are appropriately set, for example, when polypropylene is used for the heat-sealing layer, It takes about 2 seconds.

  In the following, the present invention will be described in more detail with reference to the drawings in comparison with comparative examples, and the rationality and significance of the configuration in the present invention and the superiority over the prior art will be demonstrated. .

[Example by illustration]
Examples of an easily openable lid member having a functional resin layer and a heat seal structure in the present invention are illustrated in FIGS.
In FIG. 3, the lid member having functionality in the present invention is illustrated as a laminated cross-sectional structure diagram. It is comprised from the upper part by the base material layer (35), the barrier layer (34), the functional resin layer (33), the high melting point resin layer (32), and the heat seal resin layer (31).
In FIGS. 4-6, the example of the protrusion part provided in the container flange part upper surface, the resin pool in a seal | sticker edge part, and the knob part of a cover member is illustrated.

[Measurement of melting point of each layer]
The melting point was measured by DSC (Differential Scanning Calorimeter) at a rate of temperature increase of 10 ° C./min, and the maximum peak temperature was taken as the melting point. When a plurality of melting point peaks appear, the temperature of the peak with the largest area is taken as the melting point of the layer.

[Example 1]
(Manufacture of a lid member having a functional resin layer)
* Production of oxygen-absorbing resin Steel balls were placed in a vibration mill with a capacity of 3.0 liters of a total of 1.5 kg of oxygen absorbent containing 100 parts by weight of reducing iron powder and 2 parts by weight of sodium chloride (NaCl). The mixture was then pulverized by vibration for 10 hours to attach NaCl to the iron surface to obtain an oxygen absorbent having a specific surface area of 1.8 m ² / g, an apparent density of 1.5 g / m ³ , and an average particle size of 23 μm.
As the oxygen-absorbing resin, the oxygen absorbent, titanium oxide, and ethylene-propylene random copolymer (melting point: 141 ° C.) were blended at a weight ratio of 15:10:75, and melt-kneaded with a twin-screw extruder to prepare pellets.

* Manufacture of multi-layer film for lid member A 12μm thick biaxially stretched polyethylene terephthalate (PET) film (base material layer) and a 15μm thick aluminum foil (barrier layer) are laminated with a urethane two-component adhesive, and Similarly, an ethylene-propylene block copolymer film (cushion layer) having a thickness of 30 μm was laminated on the aluminum side with a urethane two-component adhesive. Next, the oxygen-absorbing resin layer 25 μm (functional resin layer) was formed on the ethylene-propylene block copolymer (melting point 164 ° C.) film by extrusion lamination. Next, the oxygen-absorbing resin layer and biaxially stretched nylon (melting point: 220 ° C.) are coated with urethane adhesive, and the ethylene-propylene block copolymer is coated on the biaxially stretched nylon film (high melting point resin layer) with urethane adhesive. A polymer film (heat seal layer) was laminated to produce a multilayer film for a lid member.

(Manufacture of multilayer container body)
A sheet composed of an outer layer (300 μm polypropylene), an adhesive layer (15 μm maleic anhydride modified polypropylene), a barrier layer (30 μm EVOH), and an adhesive layer (15 μm maleic anhydride modified polypropylene) inner layer (500 μm polypropylene) was formed into a sheet by multilayer extrusion. After that, deep drawing is performed with a normal vacuum pressure forming machine that can form a heat seal ridge on the flange surface of the container opening, and the outer diameter is 78 mm, the flange width is 8 mm, the height is 54 mm, and the inner volume is 180 ml. Deep drawn containers were formed.

(Manufacture of retort food containers)
The cooked food is stored in the container body, the lid member is heat sealed at 190 ° C for 2 seconds, punched into a predetermined shape, retort sterilized at 120 ° C for 30 minutes, sealed and stored And the sealing property at the time of retort, the easy-opening property of a cover member, exposure of the functional material at the time of peeling of a cover member, and the preservation | save property of the flavor of stored food / beverage products were measured.

[Example-2]
The same operation as in Example 1 was performed except that the multilayer film for a lid member in Example 1 was produced as follows.
A 12 μm thick biaxially stretched polyethylene terephthalate (PET) film (base material layer) and a 15 μm thick aluminum foil (barrier layer) are laminated with a urethane-based two-component adhesive, and the aluminum foil side has a thickness of 30 μm. Similarly, an ethylene-propylene block copolymer film (cushion layer) was laminated with a urethane two-component adhesive. Next, an oxygen-absorbing resin layer 25 μm (functional resin layer) of paragraph 0058 was formed on this ethylene-propylene block copolymer (melting point 164 ° C.) film by extrusion lamination, and at the same time modified with ethylene-propylene block copolymer / maleic anhydride PP / 6 nylon (melting point: 220 ° C.) / Maleic anhydride modified polypropylene / ethylene-propylene block copolymer (melting point: 163 ° C.) multilayer film (layer thickness: 50 μm, each layer: 15: 5: 10: 5: 15 μm, innermost outer layer (Ethylene-propylene block copolymer of 10% titanium oxide) was sandwich-laminated. Thus, the multilayer film for lid members was produced.

[Example-3]
In Example 1, the material used for the high melting point resin was changed to poly-4-methylpentene-1 (melting point: 232 ° C.), and the measurement was carried out.
[Comparative Example-1]
In Example-1, the measurement was carried out in the same manner as in Example-1 under the condition that the high melting point resin layer was not used.
[Comparative Example-2]
In Example-1, the high melting point resin layer was changed to a resin having the same melting point as the heat seal resin, and the measurement was performed in the same manner as in Example-1.

[Example-4]
(Manufacture of a lid member having a functional resin layer)
* Production of oxygen-absorbing resin Steel balls were placed in a vibration mill with a capacity of 3.0 liters of a total of 1.5 kg of oxygen absorbent containing 100 parts by weight of reducing iron powder and 2 parts by weight of sodium chloride (NaCl). The mixture was then pulverized by vibration for 10 hours to attach NaCl to the iron surface to obtain an oxygen absorbent having a specific surface area of 1.8 m ² / g, an apparent density of 1.5 g / m ³ , and an average particle size of 23 μm.
As the oxygen-absorbing resin, the above-mentioned oxygen absorbent, ethylene-propylene random copolymer, linear low-density polyethylene, and maleic anhydride-modified polypropylene resin are blended at a weight ratio of 1: 7: 1: 1, and pellets are obtained. It was created.

* Manufacture of multi-layer film for lid member A 12μm thick biaxially oriented polyethylene terephthalate (PET) film (base material layer) and a 7μm thick aluminum foil (barrier layer) are laminated with a urethane two-component adhesive, and Similarly, an ethylene-propylene block copolymer film having a thickness of 30 μm was laminated on the aluminum side with a urethane two-component adhesive. After aging this film, an ethylene-propylene resin film containing 5% titanium oxide on the secondary side is disposed on the secondary side, and the oxygen-absorbing resin layer is extruded and laminated by an extrusion coater. To sandwich lamination. Next, a 15 μm thick biaxially stretched nylon (high melting point resin layer) was laminated on the ethylene-propylene resin film by dry lamination, and then a Dainippon Ink ET3800 easy peel film with a thickness of 30 μm was placed on the nylon film. Dry lamination was performed with a liquid urethane adhesive, followed by aging to produce a multilayer film for a lid member, which was used as a test sample.

(Manufacture of multilayer container body)
In the production of the main body container shown in Example 1, the shape is changed to a shape in which the flange portion is flat in the molding die, and the others are molded under the same conditions, and the heat sealing flat is formed on the flange surface of the container opening portion. Deep drawing was performed by a normal vacuum / pressure forming machine capable of forming a part, and a multilayer deep drawing container having a mouth outer diameter of 78 mm, a flange width of 8 mm, a height of 54 mm, and an internal volume of 180 ml was formed.

(Manufacture of retort food containers)
As in Example 1, the cooked food is stored in the container body, the lid member is heat sealed, punched into a predetermined shape, retort sterilized, sealed and stored, and sealed at the time of retort Characteristics, easy opening of the lid member, exposure of the functional material when the lid member was peeled off, and taste of the stored food and drink. As a result of the investigation, there was no problem in any of the sealing performance at the time of retorting, the easy opening of the lid member, the exposure of the functional material when the lid member was peeled off, and the taste of the stored food and drink.

[Example-5]
(Manufacture of a lid member having a functional resin layer)
* Preparation of Multilayer Film for Lid Member A 12 μm PET was formed on the base material layer, a 7 μm AL foil was formed on the barrier layer, and a 70 μm coextruded layer was formed on the functional resin layer. This coextruded layer is 10 μmL DPE / 50 μm hygroscopic layer / 10 μmL DPE, and the hygroscopic layer is a layer in which 10 wt% LDPE is blended with zeolite having a particle size of 30 μm. A high melting point resin layer was laminated with a 15 μm polypropylene film, and a heat seal layer was a 30 μm multilayer easy film E7700T (Difalen, manufactured by Dainippon Ink and Co., Ltd.).

(Manufacture of multilayer container body)
As for the container body, a laminated body in which 50 μm polyethylene film (titanium oxide 5% blend), 75 μm iron foil, and 50 μm polyethylene film (titanium oxide 5% blend) are laminated with a dry laminate is elastically punched. A circular squeezed container was prepared, and the flange edge portion was curled so that the flange portion was 7 mm wide.

(Manufacture of food containers)
As the contents, 10 pieces of 7 cm × 3 cm nori were put, and the functional lid member was heat-sealed at 130 ° C. for 2 seconds. Thereafter, the lid member was opened after being stored for 3 months, but the contents were stored in a well-dried state. Further, no zeolite was seen in the opened flange portion, and the appearance was good.
Table 1 summarizes the results of melting points and performances of the respective layers in the above Examples and Comparative Examples.

[Consideration of results of Examples and Comparative Examples]
By contrasting each of the above examples and comparative examples, in each of the examples, in the highly functional lid member and retort food container of the present invention, the sealing performance at the time of retorting, easy opening of the lid member, functionality It has been clarified that it is excellent in the exposure of the material and the taste function of the stored food.
On the other hand, in Comparative Example 1, a high melting point resin layer is not employed between the functional resin layer and the heat seal layer, and in Comparative Example 2, a resin layer is employed between the functional resin layer and the heat seal layer. However, since it is not a high melting point resin layer, the functional material is exposed at the time of opening, and the taste of the stored food is impaired.

It is a schematic perspective view which illustrates the functional container sealed with the easy-open lid member which has a functional resin layer in a prior art and this invention. It is sectional drawing which illustrates the laminated structure of the easy-open lid member which has a functional resin layer in a prior art. It is sectional drawing which illustrates the laminated structure of the easy-open lid member which has a functional resin layer in this invention. It is sectional drawing which illustrates the laminated structure of a container main body member, and the projection part of a flange part in this invention. It is sectional drawing which illustrates the resin pool of the heat seal edge part in this invention. It is sectional drawing which illustrates the container opening part in this invention.

Explanation of symbols

11: Container body 12: Lid member having a high-functional resin layer 13: Picking part 21: Heat seal layer 22: Functional resin layer 23: Barrier layer 24: Base material layer 31: Heat seal layer 32: High melting point Resin layer 33: Functional resin layer
34: Barrier layer 35: Base material layer 41: Outer layer 42: Barrier layer 43: Functional resin layer 44: Heat seal layer 45: Protruding portion 51: Flange portion 52: Resin pool 53: Heat seal resin 54: Lid member 61: Container opening 62: Flange surface 63: Heat seal part 64: Lid member 65: Mouth part 66: Peeling allowance part for peeling

Claims (5)

At least a barrier layer, and a functional resin layer formed of a laminated film material provided with a functional resin layer and a heat seal layer having oxygen absorbability, moisture absorbability, odor absorbability, and various gas absorbability functions; An easy-opening having a functional resin layer, characterized in that a high melting point resin layer having a melting point 30 ° C. higher than the melting point of the functional resin layer and the resin forming the heat seal layer is provided between the heat seal layers. Sexual lid member. In the functional resin layer, oxygen absorbability is reduced metal-based material or auto-oxidizing synthetic resin, moisture absorbency is zeolite, odor absorbability and various gas absorbencies are high silica type zeolite, each function is An easily openable lid member having a functional resin layer according to claim 1, wherein the easily openable lid member is made. The flange portion of the container which is formed of a laminate having at least a barrier layer and has a flange portion, and the upper surface of the flange portion has heat sealability, has the functional resin layer according to claim 1 or 2. An easy-open container having functionality and sealed by an easy-open lid member, wherein the openable lid member is heat-sealed and integrated. 4. An easily openable container having functionality and sealed by an easily openable lid member according to claim 3, wherein a projecting portion is provided on the entire upper surface of the flange portion. The easy-open container with functionality sealed by an easy-open lid member according to claim 3 or 4, wherein the food is stored inside the container and retort sterilized.

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