JP2001121652A - Oxygen absorbing multi layer film and deoxygenating container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oxygen absorbing multi-layer film and a deoxygenating container in which when a lid agent comprising an oxygen absorbing multi-layer film is peeled off from the container, a deoxygenating agent in an oxygen absorbing layer does not adhere to the flange of the container, and the contents can be preserved over a long period. SOLUTION: In an oxygen absorbing multi-layer film having at least three layers of a heat seal layer (layer A) of a thermoplastic resin, an oxygen absorbing layer (layer B) of an oxygen absorbing resin composition in which a deoxygenating agent is added into a thermoplastic resin, and a gas-barrier layer (layer C) of a gas barrier material, the melting point of the thermoplastic resin forming the (layer B) is higher by at least 10 deg.C than that of the thermoplastic resin forming the layer A. A deoxygenating container to which the multi-layer film is fusion-bonded is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an oxygen-absorbing multilayer film. The oxygen-absorbing multilayer film of the present invention is suitable for use as a lid material for a container.

[0002]

2. Description of the Related Art In recent years, as one of the oxygen-absorbing packaging techniques, a container is formed of a multilayer material having an oxygen-absorbing layer made of an oxygen-absorbing resin composition obtained by blending an oxygen-absorbing agent with a thermoplastic resin.
2. Description of the Related Art Packaging containers have been developed in which the gas barrier properties of the containers are improved and the containers themselves have an oxygen absorbing function. Among these, a film-shaped packaging material having an oxygen absorbing function, a so-called oxygen-absorbing multilayer film, is a heat-dissipating agent in which a deoxidizer is dispersed as an intermediate layer in a conventional gas barrier film in which a heat seal layer and a gas barrier layer are laminated. An oxygen-absorbing layer, which is a plastic resin layer, is laminated and used as a function of preventing oxygen permeation from the outside with a function of absorbing oxygen in the container, and is conventionally known as extrusion lamination, co-extrusion lamination, dry lamination, etc. It is manufactured using the manufacturing method described above.

[0003] The oxygen-absorbing multilayer film can be used as a bag of various shapes such as a four-sided seal bag or a standing pouch, or as a lid material of a gas barrier container, depending on the type and purpose of the article to be stored. As the molding method, a conventionally known method can be applied.

However, when an oxygen-absorbing multilayer film having an oxygen-absorbing layer made of a thermoplastic resin layer in which an oxygen scavenger is dispersed is used for a container lid, when opening the container, the container is heat-sealed to the container flange. In order to peel off the lid material from the container, a part of the resin constituting the heat seal layer remains on the container flange after opening, but often a part of the oxygen scavenger remains in this part, which significantly impairs the appearance of the container. Sometimes.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and it is possible to prevent the oxygen scavenger in the oxygen-absorbing layer from adhering to the heat-sealed heat-sealed portion after opening to prevent the appearance from being impaired. In particular, an object of the present invention is to provide an oxygen-absorbing multilayer film suitable as a container lid material and a deoxidizing container using the same.

[0006]

Means for Solving the Problems In view of the above-mentioned problems of the prior art, the present inventors have conducted intensive studies, and as a result, determined the melting point of the thermoplastic resin forming the oxygen absorbing layer and the melting point of the heat sealing layer. When the oxygen-absorbing multilayer film is fused to the container flange by setting at least 10 ° C. higher than the melting point of the thermoplastic resin to be heated, the temperature range in which the thermoplastic resin constituting the heat seal layer is heated and fused. Is reached, the oxygen absorbing layer can be kept in a substantially unmelted state, so that the oxygen scavenger does not migrate into the thermoplastic resin constituting the heat seal layer. Therefore, when peeling the lid material from the obtained container, it was found that the oxygen scavenger did not remain in the container flange portion and the external appearance of the container was not damaged, and the present invention was completed.

That is, the present invention provides a heat-sealing layer (layer A) made of a heat-sealable thermoplastic resin, and an oxygen-absorbing layer (layer B) made of an oxygen-absorbing resin composition obtained by mixing a deoxidizer with a thermoplastic resin. And an oxygen-absorbing multilayer film formed by laminating at least three layers of a gas barrier layer (layer C) made of a gas-barrier material, and an oxygen-absorbing layer (layer B)
Wherein the melting point of the thermoplastic resin constituting the heat-sealable layer is higher than the melting point of the thermoplastic resin constituting the heat sealing layer by 10 ° C. or more.

Hereinafter, the present invention will be described in detail. When the heat-sealing layer (layer A) constituting the oxygen-absorbing multilayer film of the present invention is used as a lid material, it serves as a heat-sealing surface with the container flange portion, and also contains articles and an oxygen-absorbing layer (layer B). As an isolating layer that prevents the oxygen absorber incorporated in the container from coming in direct contact with the oxygen absorber in the oxygen absorbing layer (layer B). It has a role as a permeating oxygen permeable layer.

The heat-sealable layer (layer A) can be used without limitation as long as it is a heat-sealable thermoplastic resin capable of fulfilling the above-mentioned role. For example, low density polyethylene, linear low density polyethylene,
Ultra low density polyethylene, medium density polyethylene, high density polyethylene, various polyethylenes such as polyethylene with metallocene catalyst, ethylene-vinyl acetate copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene -Acrylic acid copolymer,
Various ethylene copolymers such as ethylene-methacrylic acid copolymer, ethylene-methyl methacrylate copolymer, propylene homopolymer, propylene-ethylene block copolymer, propylene-ethylene random copolymer, metallocene-catalyzed polypropylene, etc. Examples include various polypropylenes, ethylene-α-olefin copolymers, polymethylpentene, ionomers, polystyrene, thermoplastic elastomers, various easy-peeling resins, and the like, and these can be used alone or in combination.

[0010] In particular, in the present invention, as the heat seal layer,
Various easy-peeling resins and films that can be heat-sealed at a relatively low temperature and are easily peeled from the container are preferably used. Easy peelable resin is a resin composition that, when used as a lid material or a heat seal layer of a container, exhibits sufficient sealing properties to protect the stored items and easy-openability that can be easily opened by hand when opening. For example, a mixture of polyethylene and polypropylene, a mixture of polyethylene or ethylene-vinyl acetate copolymer and polybutene-1, a mixture of polypropylene and polystyrene, and a mixture of ionomer and ethylene propylene copolymer. No. Specifically, the trade names include Dick Therm (manufactured by Dainippon Ink and Chemicals, Inc.), Mersen M (manufactured by Tosoh Corporation), and CMPS
(Manufactured by Du Pont-Mitsui Polychemicals Co., Ltd.), VMX (manufactured by Mitsubishi Chemical Corporation), and the like.
(Manufactured by Denki Kagaku Kogyo Co., Ltd.), Tocello CMPS (manufactured by Tocelo Co., Ltd.), VMX film (manufactured by Wada Chemical Industry Co., Ltd.)
And the like.

Further, additives such as a coloring pigment such as titanium oxide, an antioxidant, a slip material, an ultraviolet ray inhibitor, an antistatic agent and a stabilizer are added to the resin constituting the heat seal layer (layer A).
Fillers such as calcium carbonate, clay, mica, silica, etc.
A deodorant may be added. It may have a multilayer structure in which another thermoplastic resin layer is added between the heat seal layer and the oxygen absorbing layer.

The thickness of the heat seal layer (layer A) is 10 to
It is preferably 100 μm, more preferably 20 to 70 μm. The thickness of the heat seal layer (layer A) is 1
If the thickness is less than 0 μm, it is not preferable because the oxygen scavenger in the oxygen absorbing layer (layer B) may break through the heat seal layer (layer A) and be exposed on the surface during production of the oxygen absorbing multilayer film. On the other hand, when the thickness is more than 100 μm, lamination becomes difficult, the oxygen permeability of the heat seal layer (layer A) is reduced, the oxygen absorbing performance of the oxygen-absorbing multilayer film is reduced, and the cost is further increased. Absent.

The heat sealing layer (layer A) needs to actively transmit oxygen in order for the oxygen scavenger in the oxygen absorbing layer (layer B) to efficiently absorb oxygen. In the present invention, the oxygen permeability of the heat seal layer (layer A) is 500 cc / m ² · atm regardless of the film thickness, the number of layers, and the material composition.
Day (25 ° C., 100% RH) or more, and 700 cc / m ² · atm day (25 ° C.,
(100% RH) or more is more preferable.

The oxygen-absorbing layer (layer B) constituting the oxygen-absorbing multilayer film of the present invention is formed by dispersing an oxygen scavenger in a thermoplastic resin. After melt-kneading the oxygen scavenger and the thermoplastic resin with an extruder, extrude from a strand die, extrude a compound prepared in advance using a method such as pelletizing through a cooling step, or extrude the film onto the film from the extruder, or heat softening It is manufactured by spraying and sandwiching an oxygen scavenger between the formed thermoplastic resin films. The oxygen absorbing layer (layer B) has a role of absorbing oxygen dissolved in the container or the stored article, and a role of absorbing a small amount of oxygen entering from the outside of the container and preventing oxygen from permeating into the container.

[0015] Thermoplastic tree constituting oxygen absorption layer (layer B)
Fat does not interfere with the oxygen absorption reaction of the oxygen absorber
Its oxygen permeability coefficient is 70 cc · mm / m^Two・ Atm
-It is preferably day (25 ° C., 100% RH) or more.
Best, 100cc · mm / m ^Two・ Atm ・ day (2
5 ° C., 100% RH) or more is more preferable. Heatable
Oxygen permeability coefficient of plastic resin is 70cc · mm / m^Two・ At
If it is lower than m · day (25 ° C, 100% RH),
The acid of the thermoplastic resin against the oxygen absorption
Oxygen permeation is reduced and the oxygen absorption rate of the oxygen scavenger decreases
Therefore, it is not preferable.

Examples of the thermoplastic resin constituting the oxygen absorbing layer (layer B) include low-density polyethylene, linear low-density polyethylene, ultra-low-density polyethylene, medium-density polyethylene, high-density polyethylene, and polyethylene with a metallocene catalyst. Various polyethylenes, ethylene-vinyl acetate copolymer, ethylene-methyl acrylate copolymer,
Various ethylene copolymers such as ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl methacrylate copolymer, propylene homopolymer, propylene-ethylene block copolymer Polymers, propylene-ethylene random copolymer, various polypropylenes such as polypropylene with a metallocene catalyst, ethylene-α-olefin copolymer, various modified polyolefins, polymethylpentene,
Examples include ionomers, polystyrenes, and thermoplastic elastomers, which can be used alone or in combination.However, from the viewpoint of good oxygen permeability and versatility, among the various polyethylenes described above, And various polypropylenes are preferably used.

When the oxygen-absorbing multilayer film as a cover material is heat-sealed to the container, when the heat-sealing layer and the oxygen-absorbing layer are simultaneously melted and mixed, the oxygen scavenger moves into the heat-sealing layer. The appearance deteriorates due to the attachment of the oxygen scavenger. In the present invention, it is preferable to use a thermoplastic resin constituting the oxygen absorbing layer having a melting point higher than that of the thermoplastic resin constituting the heat sealing layer by 10 ° C. or more so that this does not occur. 20 ° C
It is more preferable to use one having a higher melting point. Conventional oxygen-absorbing multilayer film is usually the case where the thermoplastic resin constituting the heat-sealing layer and the thermoplastic resin constituting the oxygen-absorbing layer adjacent thereto are a combination of thermoplastic resins having the same or almost the same melting point. When a container is manufactured by heat sealing using this as a lid material, the heat sealing layer and the oxygen absorbing layer are simultaneously melted by heat at the time of heat sealing, and the oxygen absorbing agent in the oxygen absorbing layer partially loses the heat sealing layer. Move to. When the lid material is peeled off from the container body when opening the container thus manufactured, there is a problem that the heat seal layer mixed with the oxygen scavenger is cohesively broken and remains on the container flange, which significantly impairs the appearance of the container.

The oxygen absorbing agent dispersed in the oxygen absorbing layer (layer B) is limited as long as it can cause an oxygen absorbing reaction and can be dispersed in a thermoplastic resin. Can be used without
An oxygen scavenger composed of a combination of an oxidizable main agent and an auxiliary agent is used. A preferred base material is iron powder, and a substance that promotes the oxygen absorption reaction of the base material, for example, a metal halide or an alkali agent is used as the auxiliary agent.

As the iron powder used as the main agent, any iron powder capable of causing an oxygen absorption reaction can be used without any particular limitation on its purity and the like. For example, a part of the surface may be already oxidized. May be contained.
The iron powder is preferably in the form of particles. For example, iron powder such as reduced iron powder, sprayed iron powder, electrolytic iron powder and the like, pulverized and ground products of various irons such as cast iron and steel are used. The average particle size is
In consideration of handling properties and preventing oxygen absorption as much as possible, the thickness is preferably in the range of 1 to 100 µm, and particularly preferably in the range of 1 to 80 µm.

In the case of a deoxidizing agent using iron powder as a main component and a metal halide as an auxiliary, the metal halide as an auxiliary catalytically acts on the oxygen absorption reaction of the main agent. As the metal halide, for example, chloride, bromide or iodide of an alkali metal or alkaline earth metal is used, and chloride or iodide of lithium, sodium, potassium, magnesium, calcium or barium is preferably used. The compounding amount of the metal halide is preferably 0.1 to 20 parts by weight per 100 parts by weight of iron powder, particularly 0.1 to 5 parts by weight.
Parts by weight are preferred.

The metal halide is used together with iron powder as an essential component of the oxygen scavenger containing iron powder as a main component, but it is preferable to add the metal halide in advance so that the metal halide adheres to the iron powder and is not easily separated. . For example, a method of mixing a metal halide and iron powder using a ball mill, a speed mill, or the like, a method of embedding a metal halide in irregularities on the surface of the iron powder, a method of attaching a metal halide to the surface of the iron powder using a binder Alternatively, a method of mixing a metal halide aqueous solution and iron powder, drying the mixture, and then attaching the metal halide to the surface of the iron powder can be employed. The preferred oxygen scavenger is an iron powder-based composition containing iron powder and a metal halide, and particularly preferably a metal halide-coated iron powder-based composition in which a metal halide is attached to iron powder.

The amount of the oxygen absorbing agent in the oxygen absorbing layer (layer B) is from 10 to 70 in the resin composition constituting the oxygen absorbing layer.
% By weight, preferably 10 to 60% by weight.
Is more preferable. 10% by weight of oxygen absorber
If it is lower than this, the oxygen absorbing ability is insufficient, which is not preferable. If it is higher than 70% by weight, it becomes difficult to form the oxygen absorbing layer (layer B) or the oxygen absorbing layer is caused by the oxygen scavenger on the gas barrier layer side. This is not preferable because unevenness is transferred or the adhesive strength between the oxygen absorbing layer (layer B) and the gas barrier layer (layer C) is greatly reduced.

The thickness of the oxygen absorbing layer (layer B) is preferably in the range of 20 to 100 μm, particularly preferably in the range of 30 to 80 μm, regardless of the constituent materials. If the thickness of the oxygen absorbing layer (layer B) is less than 20 μm, it becomes difficult to form a film or the amount of the oxygen scavenger per unit area of the film becomes small, so that sufficient oxygen absorbing ability cannot be obtained. On the other hand, when the thickness is more than 100 μm, the total thickness of the film becomes large, which may cause inconvenience in handling properties and cause a problem in cost.

In the oxygen absorbing layer (layer B), various additives such as a coloring pigment such as titanium oxide, an antioxidant, a slip agent, an ultraviolet ray inhibitor, an antistatic agent and a stabilizer may be added, if necessary. Fillers such as clay, mica, silica, calcium carbonate, calcium sulfate, barium sulfate, and alumina, deodorants, and adsorbents such as activated carbon and zeolite may be added.

The gas barrier layer (layer C) of the present invention has a role of blocking oxygen entering from outside the container. Materials constituting the gas barrier layer (layer C) include, for example, metal foils such as aluminum foil, inorganic oxide deposited films such as aluminum-deposited films and silica-deposited films, polyvinylidene chloride, and saponified ethylene-vinyl acetate copolymer. And polyamides such as MX nylon and amorphous nylon. These can be used alone or in combination. Further, these stretched films may be used.

Depending on the purpose, a protective layer may be laminated on the outside of the gas barrier layer (layer C), or the oxygen absorbing layer (layer B)
An intermediate layer or a buffer layer can be laminated between the gas barrier layer (layer C) and the gas barrier layer (layer C). Examples of the material constituting these layers include various polyethylenes, various polypropylenes, polyamides such as nylon 6, nylon 66, and polyesters such as polyethylene terephthalate, and these can be used alone or in combination. These stretched films may be used. Further, the gas barrier layer (layer C) may be subjected to printing in order to improve the appearance of the container.

The lamination of the heat sealing layer (layer A), oxygen absorbing layer (layer B), and gas barrier layer (layer C) constituting the oxygen-absorbing multilayer film of the present invention includes extrusion lamination, co-extrusion lamination, and dry lamination. And the like, using a conventionally known laminating method. The oxygen-absorbing multilayer film of the present invention preferably has a thickness of 50 to 200 μm, more preferably 80 to 160 μm.

The oxygen-absorbing multilayer film of the present invention can be suitably used as a material for oxygen-absorbing bags of various shapes such as a four-side seal bag, a three-side seal bag, and a standing pouch, or as a lid material for an oxygen-absorbing container. Has performance particularly suitable as a material of a bag or a container which is opened by peeling, for example, a lid material of the container. The type of the thermoplastic resin constituting the heat seal layer (layer A) of the oxygen-absorbing multilayer film needs to consider the heat-fusibility with the container body bonding surface. The container body to which the lid member is bonded is made of a gas barrier material. In the container body, gas barrier properties such as gas-barrier multilayer containers having metal-foil resins or metal foils such as saponified ethylene-vinyl acetate copolymer or MX nylon in the middle layer or surface layer, and gas barrier properties of metal containers and glass containers Preferably, a container is used. A preferable container body uses a gas barrier material whose flange surface to which the lid member is bonded is made of a heat-sealable thermoplastic resin. As the gas barrier container body, a container body made of a deoxidized multilayer body can also be used. In this case, it is preferable to use a container body made of the oxygen-desorbed multilayer film of the present invention.

When the oxygen-absorbing multilayer film of the present invention is heat-sealed to the opening of the gas barrier container, a conventionally used heat sealer can be used. At that time, if the pressure and temperature of the heat sealer are set higher than necessary, the heat seal layer will melt and the viscosity will decrease, it will protrude from the heat seal part to the side, and the oxygen absorbing layer will melt and mix with the heat seal layer Care must be taken because the oxygen scavenger may remain on the container flange. A preferable heat sealing temperature is a temperature higher than the melting point of the thermoplastic resin forming the heat sealing layer and not exceeding the melting point of the thermoplastic resin forming the oxygen absorbing layer.

The packaging container using the oxygen-absorbing multilayer film of the present invention is not limited. For example, milk, juice,
Liquid drinks such as sake, whiskey, shochu, coffee, tea, jelly drinks, health drinks, etc., seasonings, sauces, soy sauce, dressings, liquid stocks, seasonings such as mayonnaise, miso, ground spices, jams, creams, chocolate pastes Such as pasty foods, liquid soups, boiled foods, pickles,
Liquid foods represented by liquid processed foods such as stews, raw noodles such as soba, udon, ramen and boiled noodles, rice before cooking such as polished rice, moisture-conditioned rice, unwashed rice, cooked cooked rice, and gomeshi , Red rice, processed rice products such as rice porridge, powdered soup, high-moisture foods represented by powder seasonings such as soup stock, and other solid or solution chemicals such as pesticides and pesticides, liquids and Paste medicine, lotion, makeup cream, lotion,
Various items such as hair styling, hair dye, shampoo, soap, detergent, etc. can be stored, and no oxygen enters from outside of the container, and oxygen inside the container is absorbed by the oxygen scavenger. , Prevent oxidation and corrosion of goods,
Good quality can be maintained for a long time.

[0031]

Embodiments of the present invention will be described below.
Note that the present invention is not limited to these examples. Example 1 An aqueous solution containing 100 parts by weight of reduced iron powder having an average particle diameter of 30 μm, 3 parts by weight of calcium chloride, and calcium sulfate 0.5
The parts by weight were mixed and dried to obtain a granular salt-coated iron powder-based oxygen scavenger. 30 parts by weight of the obtained oxygen scavenger, 10 parts by weight of titanium oxide, propylene-ethylene random copolymer (manufactured by Chisso Corp., trade name; Chissopolypro F8090, melting point 1)
(53 ° C.) 60 parts by weight are mixed, melt-kneaded with a 35 mm twin screw extruder, made into a strand through a strand die, cooled with a net belt with a blower, and then pelletized with a pelletizer to obtain an oxygen-absorbing compound 1. Was.
Next, using an extruder, an extruder equipped with a T-die, an extruder laminator equipped with a cooling roll, a winder, and the like, a polypropylene film (made by Toyobo Co., Ltd., trade name: Pyren film P1)
128, hereinafter abbreviated as CPP), the oxygen-absorbing compound 1 was extruded and laminated from the first extruder to obtain a laminate A composed of CPP (30 μm) / oxygen absorbing layer (30 μm). Next, an easy-peelable sealant film (manufactured by Tocelo Co., Ltd., trade name: Tocello CMPS011C, melting point 9) was formed on the oxygen absorbing layer surface of the laminate A.
9 ° C., 123 ° C., hereinafter abbreviated as CMPS) is dry-laminated via a urethane-based adhesive, and is CPP (30 μm).
A laminate B composed of / oxygen absorbing layer (30 μm) / CMPS (30 μm) was obtained. Next, polyethylene terephthalate (hereinafter abbreviated as PET) is provided on the CPP surface of the laminate B.
/ Printing ink / Gas barrier biaxially stretched nylon 6 / MX
The super barrier surface of a gas barrier film made of nylon / nylon 6 film (manufactured by Mitsubishi Kagaku Kojin Pax Co., Ltd., trade name: Super Neal SP, hereinafter abbreviated as Super Neal) is dry-laminated via a urethane-based adhesive. An oxygen-absorbing multilayer film 1 comprising PET (12 μm) / printing ink / super neal (15 μm) / CPP (30 μm) / oxygen absorbing layer (30 μm) / CMPS (30 μm) was obtained. Next, a tray-shaped gas barrier container main body (layer constitution; polypropylene / adhesive resin / saponified ethylene vinyl acetate copolymer / adhesive resin / polypropylene), inner dimensions: 15 cm long × 9 cm wide × 3 cm deep,
Cooked rice was placed in a flange width of 10 mm) and overlapped so that the heat-sealing layer surface of the oxygen-absorbing multilayer film 1 faced the polypropylene surface of the container body, and the flange portion was heat-sealed at 140 ° C. After storing at 20 ° C. for 10 days, the oxygen-absorbing multilayer film 1 was peeled from the container, the peeling surface of the container flange portion was observed, and the preserved state of the color and taste of cooked rice was evaluated organoleptically. Table 1 shows the results.

Comparative Example 1 Metallocene polyethylene (trade name, manufactured by Dow Chemical Co., Ltd.) instead of the propylene-ethylene random copolymer
An oxygen-absorbing compound 2 was produced in the same manner as in Example 1 except that affinity PT1450, melting point: 100 ° C.) was used. Next, using two extruders, an extruder equipped with a T-die, an extruder laminator equipped with a cooling roll, a winder, and the like, PET / printing ink / super neal / low density polyethylene fed from the unwinder ( The oxygen-absorbing compound 2 was extruded and laminated between the LDPE surface of the LDPE (hereinafter abbreviated as LDPE) and the CMPS film, and PET (12 μm) / printing ink / super neal (15 μm) / LDPE (20 μm)
m) / oxygen absorbing layer (30 μm) / heat sealing layer (30
μm) was obtained. Next, in the same manner as in Example 1, the heat-sealing layer surface of the oxygen-absorbing multilayer film 2 and the polypropylene surface of the container body face each other on the tray-shaped gas barrier container body, and the flange portion is heat-sealed at 140 ° C. did. 1 at 20 ° C
After storage for 0 days, the oxygen-absorbing multilayer film 2 was peeled off from the container, the peeled surface of the container main body flange portion was observed, and the preserved state of the color and taste of the cooked rice was evaluated organoleptically. Table 1 shows the results.

[0033]

[Table 1] (1) The attachment of an oxygen scavenger to the peeled surface of the container body flange was observed.

As is clear from the results shown in Table 1, the oxygen-absorbing multilayer film of the present invention in which the melting point of the thermoplastic resin forming the oxygen absorbing layer is higher than the melting point of the thermoplastic resin forming the heat sealing layer by 10 ° C. or more. Since the oxygen-absorbing layer and the heat-sealing layer can be heat-sealed with sufficient adhesive strength to the container body without melting and mixing even when heat-sealing, the oxygen absorber The oxygen-absorbing agent did not transfer to the layer, and the oxygen-absorbing agent did not remain on the heat-sealing trace of the container body flange even when the lid made of the oxygen-absorbing multilayer film was peeled off from the container body. On the other hand, in Comparative Example 1 in which a lid made of a deoxidizing multilayer film in which the melting point of the thermoplastic resin forming the oxygen absorbing layer is almost the same as the melting point of the thermoplastic resin forming the heat sealing layer, heat sealing was performed. When performed, the thermoplastic resin constituting the oxygen-absorbing layer is also melted, and the two layers are mixed to partially transfer the oxygen-absorbing agent to the heat-sealing layer. Therefore, the lid made of the oxygen-absorbing multilayer film is obtained from the obtained container. On the flange portion of the container main body after the material was peeled off, the oxygen scavenger adhered to the trace of the heat seal, which deteriorated the appearance of the container.

[0035]

As described above, the oxygen-absorbing multilayer film of the present invention has a certain melting point difference between the thermoplastic resin constituting the heat-sealing layer and the thermoplastic resin constituting the oxygen-absorbing layer. This prevents the oxygen scavenger from migrating into the heat-sealing layer, does not impair the appearance of the container after opening, and allows the contents to be stored for a long period of time. Thus, the oxygen-absorbing multilayer film of the present invention is extremely useful as a practically useful packaging material that enables long-term storage of stored articles such as various foods and pharmaceuticals. In the oxygen-absorbing multilayer film of the present invention, as the thermoplastic resin constituting the oxygen-absorbing layer and the thermoplastic resin constituting the heat-sealing layer, the melting point of the thermoplastic resin constituting the oxygen-absorbing layer constitutes the heat-sealing layer. By using a combination in which the melting point of the thermoplastic resin is higher than 10 ° C. or higher, preferably 20 ° C. or higher, the oxygen-absorbing container obtained by heat-sealing the thermoplastic resin by heat-sealing is In addition, the heat seal layer to which the oxygen scavenger has migrated does not remain on the container body flange portion, and the container appearance is not impaired.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) B65D 81/26 B65D 81/26 L // C08K 3/08 C08K 3/08 3/16 3/16 C08L 23/02 C08L 23/02 (72) Inventor Sotaro Hiramatsu 5-6-2 Higashi-Hachiman, Hiratsuka-shi, Kanagawa Prefecture F-term in Hiratsuka Research Laboratory, Mitsui Gas Chemical Co., Ltd. EE32 EE33 GB13 4F100 AA06 AA07 AB02 AK01A AK01B AK01C AK07 AK42 AK47 AK48 AK51G AK64 AK69 BA03 BA06 BA10A BA10C BA15 CA09B CB00 CB03 J DA01 DA03 DE01 EC03 EC032 EC182 EH15 GB16 EB18 GB18 EJ38 GB18 YY00B 4J002 BB031 BB051 BB061 BB071 BB081 BB121 BB151 BB161 BB231 BC031 BP021 GG01

Claims (3)

[Claims] 1. A heat-sealing layer (layer A) made of a heat-sealing thermoplastic resin, an oxygen-absorbing layer (layer B) made of an oxygen-absorbing resin composition obtained by mixing a deoxidizer with a thermoplastic resin, and gas barrier properties. An oxygen-absorbing multilayer film in which at least three layers of a gas barrier layer (layer C) made of a material are laminated, wherein the melting point of the thermoplastic resin constituting the oxygen-absorbing layer (layer B) is the heat of the heat-sealing layer. An oxygen-absorbing multilayer film, which is higher by at least 10 ° C. than the melting point of the plastic resin. 2. The container according to claim 1, wherein the oxygen-absorbing multilayer film according to claim 1 is used as a lid, and the surface to which the lid is adhered is made of a gas barrier material made of a heat-sealable thermoplastic resin. Deoxygenated container fused. 3. A heat-sealing layer (layer A) made of a heat-sealable thermoplastic resin, an oxygen-absorbing layer (layer B) made of an oxygen-absorbing resin composition obtained by mixing a deoxidizer with a thermoplastic resin, and gas barrier properties. An oxygen-absorbing multilayer film in which at least three layers of a gas barrier layer (layer C) made of a material are laminated, wherein the melting point of the thermoplastic resin constituting the oxygen-absorbing layer (layer B) is the heat of the heat-sealing layer. A cover member made of an oxygen-absorbing multilayer film higher than the melting point of the thermoplastic resin by 10 ° C. or more, and a gas barrier container body made of a heat-sealable thermoplastic resin with a surface to which the cover member is adhered, A method for producing a deoxygenating container, comprising heat-sealing at a temperature higher than the melting point of the thermoplastic resin and not exceeding the melting point of the thermoplastic resin constituting the oxygen absorbing layer.