JP2000238198A - Oxygen absorbable multilayered film and packaging container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oxygen absorbable multilayered film not generating a change in appearance caused by interlaminar peeling even under various use conditions and also excellent in smell. SOLUTION: An oxygen absorbable multilayered film consisting of a heat sealing layer comprising a thermoplastic resin having oxygen permeability, an oxygen absorbing layer comprising a thermoplastic resin having an oxygen scavenger dispersed therein, a low density polyethylene layer comprising high- pressure low density polyethylene, an anchor coat layer and a gas barrier layer is produced through a process wherein a molten high-pressure low density polyethylene resin is laminated on the anchor coat agent applied to the surface of the gas barrier layer. By this constitution, the oxygen absorbable multilayered film excellent not only in interlaminar bonding but also in odorless properties can be utilized as a packing material capable of preserving a housing article such as various foods or medicines over a long period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer film having an oxygen absorbing function, a packaging container, and a manufacturing method. In detail, the anchor coating surface of the gas barrier layer to which the anchor coating agent is applied, and the oxygen absorbing layer surface of the laminated film composed of the heat sealing layer and the oxygen absorbing layer in which the oxygen absorbing agent is dispersed in the thermoplastic resin are made of low-density polyethylene. It has a multilayer structure that is adhered through, and by applying an anchor coating agent, there is no peeling of the gas barrier layer even during long-term storage, and between the anchor coating agent application surface and the oxygen absorbing layer Since the surface is oxidized and the low-density polyethylene layer with increased adhesiveness is laminated, the oxygen absorbing layer can be laminated at a relatively low temperature, so that the oxidation of the oxygen absorber and the oxidative deterioration of the thermoplastic resin are reduced, The present invention relates to an oxygen-absorbing multilayer film characterized in that generation of an unpleasant odor is small, a packaging container comprising the same, and a method for producing the same.

[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 mixing a deoxidizer with a thermoplastic resin.
A packaging container has been developed in which the gas barrier property of the container is improved and the container itself has an oxygen absorbing function.
Of these, an oxygen-absorbing multilayer body having a small total thickness, a so-called oxygen-absorbing multilayer film, is obtained by dispersing a deoxidizer as an intermediate layer in a conventional gas-barrier multilayer 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. Specifically, Japanese Patent Application Laid-Open No. 9-40024
As disclosed in Japanese Patent Application Laid-Open Publication No. H10-260, there is known a method of bonding a multilayer body in which a thermoplastic resin layer, an oxygen absorbing layer, and a heat seal layer are laminated, and a gas barrier film using an adhesive for dry lamination. I have. Also, Japanese Patent Application Laid-Open No. 2-565
As disclosed in Japanese Patent No. 47, there is known a method of laminating an oxygen absorbing layer and a heat sealing layer on a metal foil as a base material by extrusion lamination or co-extrusion lamination.

[0003]

However, in the method of bonding a laminate comprising a thermoplastic resin layer, an oxygen absorbing layer, and a heat sealing layer to a gas barrier film using a dry laminating adhesive, Since the laminating step and the bonding step of the gas barrier layer must be separate steps, the manufacturing step becomes complicated. In addition, a large amount of adhesive must be used to bond the laminate including the gas barrier layer and the oxygen absorbing layer, so that the manufacturing cost increases and a certain period of time is required to remove the solvent contained in the adhesive. Aging was required, and in some cases, the product produced a solvent odor.

In a method of directly laminating a thermoplastic resin layer on a gas barrier film by extrusion lamination or co-extrusion lamination, the adhesive strength is weak, and the gas barrier layer may be peeled off depending on use conditions such as long-term storage after heat treatment. And the appearance of the container may be impaired during use. Also, if the oxygen absorbing layer is extruded and laminated at a high temperature to increase the adhesive strength, the oxygen absorbing agent in the oxygen absorbing layer is oxidized, generating an unusual odor, and the thermoplastic resin is oxidized and deteriorated by the influence of the oxygen absorbing agent. However, the decomposition odor of the resin was sometimes generated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and in particular, has a high adhesive strength between layers and can maintain a good appearance over a long period of time under various use conditions. An object of the present invention is to provide an oxygen-absorbing multilayer film, a packaging container, and a method for producing the same, which have a low off-odor.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies in view of the above-mentioned problems of the prior art, and as a result, after applying an anchor coat agent to a gas barrier film, a low-density polyethylene layer, By laminating the absorption layer and the heat sealing layer, it was found that it was possible to manufacture an oxygen-absorbing multilayer film with a simple manufacturing process, high adhesive strength of each layer, and low off-odor, and completed the present invention. It led to.

That is, the present invention provides a heat sealing layer made of a thermoplastic resin having oxygen permeability, an oxygen absorbing layer made of a thermoplastic resin in which an oxygen scavenger is dispersed, a high-pressure low-density polyethylene resin layer, and an anchor coating agent layer. And an oxygen-absorbing multilayer film comprising a gas barrier layer and a method for producing the same. The present invention also provides an oxygen-absorbing layer surface of a laminated film comprising an anchor-coat surface of a gas barrier film coated with an anchor coating agent, and an oxygen-absorbing layer in which a deoxidizer composition is dispersed in a heat seal layer and a thermoplastic resin. But,
The present invention relates to an oxygen-absorbing multilayer film adhered through low-density polyethylene and a method for producing the same. Furthermore, the present invention relates to a packaging container in which part or all of the packaging container is made of the above-described oxygen-absorbing multilayer film.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The heat-sealing layer constituting the oxygen-absorbing multilayer film of the present invention is a portion that becomes a sealant when the oxygen-absorbing multilayer film of the present invention is used for a part or all of a packaging container. In addition, it functions as an isolation layer that separates the stored articles from the oxygen absorbing layer, and as an oxygen permeable layer that efficiently transmits oxygen because oxygen in the packaging container is quickly absorbed by the oxygen scavenger in the oxygen absorbing layer. Has a role.

As the heat-sealing layer constituting the oxygen-absorbing multilayer film of the present invention, any thermoplastic resin having oxygen permeability that can fulfill the above-mentioned role can be used without limitation. . For example, various polyethylenes such as low-density polyethylene, linear low-density polyethylene, ultra-low-density polyethylene, metallocene-catalyzed polyethylene, ethylene-vinyl acetate copolymer, ionomer, ethylene-methyl acrylate copolymer, ethylene-acryl Ethyl acrylate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl methacrylate copolymer, propylene homopolymer, propylene-ethylene block copolymer, propylene-ethylene random copolymer And various metallocene-catalyzed polypropylenes such as polypropylene, polymethylpentene, thermoplastic elastomers, etc., and these can be used alone or in combination.

In particular, in the present invention, it is important to select a material having good oxygen permeability and being fusible with the thermoplastic resin constituting the oxygen absorbing layer, because of the oxygen absorbing performance of the film and the manufacturing process. The above-mentioned various polyethylenes are preferably used because they are preferable in terms of surface. The heat-sealing layer in the oxygen-absorbing multilayer film of the present invention may have a single-layer structure of the above resin or a multilayer structure of two or more layers, and may be laminated by extrusion lamination or various lamination using a film formed in advance. It may be laminated by a method. In addition, the heat seal layer contains coloring pigments such as titanium oxide, additives such as antioxidants, slip agents, antistatic agents and stabilizers, fillers such as calcium carbonate, clay, mica and silica, and deodorants. It may be added.

The thickness of the heat sealing layer constituting the oxygen-absorbing multilayer film of the present invention is 10 to 10 irrespective of the number of layers.
It is preferably 0 μm, more preferably 20 to 60 μm. If the thickness of the heat sealing layer is less than 10 μm, the oxygen absorbing agent of the oxygen absorbing layer is exposed on the surface and the heat sealing strength is undesirably reduced. On the other hand, when the thickness of the heat seal layer is more than 100 μm, it is not preferable because lamination becomes difficult, the oxygen permeability is reduced, the oxygen absorption performance of the film is reduced, and the cost is problematic.

The heat-sealing layer constituting the oxygen-absorbing multilayer film of the present invention must actively transmit oxygen in order for the oxygen absorber in the oxygen-absorbing layer to efficiently absorb oxygen. In the present invention, the oxygen permeability of the heat seal layer is 500 cc / regardless of its thickness, number of layers, and material composition.
m ² · atm · day (25 ° C., 100% RH) or more, preferably 700 cc / m ² · atm · day
(25 ° C., 100% RH) or more is more preferable.
Oxygen permeability is 500cc / m ² · atm · day (25
(° C, 100% RH), the rate of oxygen permeation of the heat-sealing layer is limited by the oxygen absorption performed by the oxygen scavenger in the oxygen-absorbing layer, and a sufficient oxygen-absorbing rate cannot be obtained. .

The oxygen-absorbing layer constituting the oxygen-absorbing multilayer film of the present invention is obtained by dispersing an oxygen scavenger in a thermoplastic resin. After melt-kneading the oxygen absorber and the thermoplastic resin by an extruder, the extruder is extruded from a strand die, and is manufactured by extruding a previously prepared compound into a film from an extruder using a method such as pelletizing through a cooling step. . The oxygen absorbing layer 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 permeation into the inside of the container.

The thermoplastic resin constituting the oxygen absorbing layer of the present invention has an oxygen permeability coefficient of 70 cc · mm / m ² · atm · d so as not to hinder the oxygen absorbing reaction of the oxygen absorber.
ay (25 ° C., 100% RH) or more, and 100 cc · mm / m ² · atm · day (25 ° C., 1% RH).
(00% RH) or more. The oxygen permeability coefficient of the thermoplastic resin is 70 cc · mm / m ² · atm · day
If the temperature is lower than (25 ° C., 100% RH), the rate of oxygen permeation of the thermoplastic resin is limited with respect to the oxygen absorption performed by the oxygen absorber, and the oxygen absorption rate of the oxygen absorber decreases.
Not preferred.

Since the oxygen-absorbing layer constituting the oxygen-absorbing multilayer film of the present invention is laminated with a low-density polyethylene layer, it is necessary to use a thermoplastic resin which is fusible with low-density polyethylene as its constituent material. Is preferred. As the thermoplastic resin, for example, various polyethylenes exemplified by low-density polyethylene, linear low-density polyethylene, ultra-low-density polyethylene, polyethylene catalyzed by a metallocene catalyst, ethylene-vinyl acetate copolymer, ionomer, ethylene-methyl acrylate copolymer Polymer, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer,
Ethylene-methacrylic acid copolymer, ethylene-methyl methacrylate copolymer, thermoplastic elastomers, and the like, and these can be used alone or in combination. Among them, various polyethylenes are particularly preferably used.

The oxygen-absorbing agent dispersed in the oxygen-absorbing layer constituting the oxygen-absorbing multilayer film of the present invention is capable of causing an oxygen-absorbing reaction, and may be dispersed in a thermoplastic resin. It can be used without limitation as long as it is possible, but preferably, an oxygen scavenger composed of a combination of an oxidizable main agent and an auxiliary agent is used. Iron powder is preferably used as the main agent, and a chemical substance that promotes the oxygen absorption reaction of the main agent, for example, a metal halide or an alkali agent is used as the auxiliary agent.

As the iron powder 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, It may contain a metal. Also,
The iron powder is preferably granular, and for example, iron powder such as reduced iron powder, sprayed iron powder, electrolytic iron powder and the like, and crushed or ground iron products such as cast iron and steel are used. The average particle size is preferably in the range of 1 to 100 μm in consideration of handleability and reducing the thickness of the oxygen absorbing layer and preventing as much as possible the unevenness of the oxygen scavenger appearing on the film appearance, In particular, the thickness is preferably in the range of 1 to 80 μm.

In the case of an oxygen scavenger composition containing 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, chlorides, bromides, iodides of alkali metals or alkaline earth metals are used, and lithium, sodium, potassium, magnesium,
Calcium or barium chloride or iodide is preferably used. The compounding amount of the metal halide is iron powder 10
0.1 to 20 parts by weight, preferably 0.1 to 5 parts by weight, per 0 parts by weight.

The metal halide is used together with the iron powder as an essential component of the oxygen-absorbing composition containing iron powder as a main component.
It is preferable to mix and add them in advance so that they do not easily separate from the iron powder. For example, a method of mixing a metal halide and iron powder using a ball mill, a speed mill, or the like,
Method of embedding metal halide in irregularities on the surface of iron powder, method of attaching metal halide to the surface of iron powder using a binder, mixing metal halide aqueous solution and iron powder, drying and halogenating the surface of iron powder A method of attaching a metal or the like can be employed. A preferred oxygen scavenger composition 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 adhered to iron powder.

The amount of the oxygen scavenger in the oxygen-absorbing layer constituting the oxygen-absorbing multilayer film of the present invention is 10-70.
% By weight, preferably 10 to 60% by weight.
Is more preferable. 10% by weight of oxygen absorber
If it is lower, the oxygen absorbing ability is insufficient, which is not preferable. If it is higher than 70% by weight, it is difficult to form an oxygen absorbing layer, which is not preferable.

The thickness of the oxygen-absorbing layer constituting the oxygen-absorbing multilayer film of the present invention is 20 to 10 regardless of the constituent materials.
It is preferably in the range of 0 μm, particularly preferably 3 μm.
The range is from 0 to 80 μm. The thickness of the oxygen absorbing layer is 20μ
When the thickness is smaller than m, film formation becomes difficult, or the amount of the oxygen scavenger per unit area of the film decreases, so that sufficient oxygen absorption performance 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 of the present invention, if necessary, various additives such as coloring pigments such as titanium oxide, antioxidants, slip agents, antistatic agents, stabilizers, clay, mica, silica And fillers such as calcium carbonate, calcium sulfate and barium sulfate, deodorants, and adsorbents such as activated carbon and zeolite.

The low-density polyethylene layer constituting the oxygen-absorbing multilayer film of the present invention is a layer for bonding the oxygen-absorbing layer and the gas barrier layer, and is made of a high-pressure polyethylene resin having a density of 0.90 to 0.94. Layer. Low pressure process low density polyethylene layers such as linear low density polyethylene are excluded. The high-pressure low-density polyethylene constituting this layer is not particularly limited as long as it can be extruded and laminated, and various brands can be used.
Preferably, the melt index is 4 to 12 g / 10 min (190 ° C, 2.16 kg), and the melting point is 100 to 120 ° C.
Is a low density polyethylene. In addition, since the low-density polyethylene layer of the present invention is a layer having a role as an adhesive layer, a filler or a pigment that reduces the adhesiveness, an antioxidant or a slip that reduces the adhesive strength over time, or the like is used. Agent,
It is preferable that additives such as dispersants are not added to the low density polyethylene layer as much as possible.

By extruding the heat-melted high-pressure low-density polyethylene resin onto the anchor coat agent layer in a molten state, the resin surface is oxidized by air to produce polar functional groups such as carbonyl groups, and The bonding strength between the layers when bonded is improved. For this reason, the oxygen absorbing layer can be stacked at a relatively low temperature, and the oxidative deterioration and the like of the resin constituting the oxygen absorbing layer are reduced, and the generation of an unusual odor is suppressed. Preferred high pressure low density polyethylene resins are low density polyethylene resins having a branched chemical structure. When a low-density polyethylene resin with a branched chemical structure is used as the resin layer laminated on the anchor coat agent layer, it adheres to the gas barrier layer compared to when a linear low-density polyethylene resin or high-density polyethylene resin is used. The bonding strength between the layers at the time of this is improved.

The thickness of the low density polyethylene layer in the present invention is preferably in the range of 10 to 40 μm, particularly preferably 20 to 30 μm. If the thickness is less than 10 μm, it is not preferable because lamination becomes difficult or the adhesiveness may decrease. When the thickness is more than 40 μm, the total thickness of the oxygen-absorbing multilayer film becomes large, which may cause inconvenience in handling, which is not preferable.

The gas barrier layer constituting the oxygen-absorbing multilayer film of the present invention has a role of blocking oxygen entering from outside the container when the packaging container is formed from the film. Materials constituting the gas barrier layer include metal foils such as aluminum foil, polyvinylidene chloride, saponified ethylene-vinyl acetate copolymer, polyamides such as nylon 6, nylon 66, MX nylon, amorphous nylon, and polyethylene terephthalate. Polyester, an inorganic oxide-deposited film such as an aluminum-deposited film or a silica-deposited film, or the like can be used alone or in combination. The oxygen permeability of the gas barrier layer is preferably as small as possible due to workability and cost, and 100 cc / m ² · atm · day (25 ° C., 50%
RH) or less, more preferably 5
0 cc / m ² · atm · day (25 ° C., 50% RH) or less. By doing so, when a packaging container is manufactured using the oxygen-absorbing multilayer film according to the present invention,
The amount of oxygen entering from the outside can be reduced, and the storage stability of the stored articles can be further improved.

It is preferable to provide a protective layer on the outside of the gas barrier layer constituting the oxygen-absorbing multilayer film of the present invention, if necessary. As the protective layer, polyester such as polyethylene terephthalate, polyamide such as nylon 6, and polyolefin such as polypropylene and polyethylene can be used, and these stretched films may be used. The protective layer can have a single layer structure of the thermoplastic resin or a multilayer structure of two or more layers, and the film thickness is
It is preferable to set the thickness in the range of 10 to 50 μm regardless of the number of layers so that the film thickness is not increased more than necessary.

In the oxygen-absorbing multilayer film of the present invention, the oxygen-absorbing layer and the gas barrier layer are bonded to the low-density polyethylene resin layer via an anchor coat agent. By adopting this configuration, the adhesive strength between the gas barrier layer and the oxygen absorbing layer is improved, and even when the film is used as a packaging container and stored for a long time, the peeling between the gas barrier layer and the oxygen absorbing layer does not occur. The appearance can be maintained.

The anchor coating agent used in the oxygen-absorbing multilayer film of the present invention is applied on the gas-barrier layer in order to enhance the interlayer adhesion between the gas-barrier layer and the oxygen-absorbing layer. As the anchor coating agent, various anchor coating agents such as an organotitanium anchor coating agent, an isocyanate anchor coating agent, a polybutadiene anchor coating agent, and a polyethyleneimine anchor coating agent can be used. Among these, an isocyanate-based anchor coating agent is preferably used, because it is excellent and can store various articles when the oxygen-absorbing multilayer film of the present invention is used as a packaging container.

The isocyanate anchor coating agent includes
One-pack type such as triisocyanate having an isocyanate group at the terminal obtained by reacting tolylene diisocyanate with a polyhydric alcohol such as trimethylolpropane, and a type of polycondensation after mixing tolylene diisocyanate with polyester and then polycondensing In particular, in the present invention, since the cured film is flexible, when high adhesive strength is required, it can be adjusted according to the purpose such as increasing the amount of the anchor coating agent applied. Therefore, a two-pack type isocyanate anchor coating agent is more preferably used.

The isocyanate-based anchor coating agent is, like the urethane-based dry laminating adhesive, a solid component exhibiting an adhesive function dissolved in an organic solvent. On the other hand, the anchor coat agent plays a role of improving adhesion between a film serving as a base material and a thermoplastic resin film extruded in a molten state.
Therefore, the concentration of the solid component for improving the adhesiveness is much lower than that of the adhesive for dry lamination, and the amount of the applied solid component can be very small. Generally, the adhesive for dry lamination has a solid concentration in a solution of 20 to
It is used under the condition that the solid content after removal of the solvent is as high as 30% by weight and the solid content is 2.5 to 4.5 g / m ² ,
The anchor coat agent has a solid content concentration of 4 to 6% in the solution, and the solid content application amount after removing the solvent is 0.1 to 0.1%.
It is used under the condition of 3 g / m ² . With respect to the coating amount of the anchor coating agent in the present invention, the coating amount of the anchor coating agent is slightly larger than the normal coating amount in order to prevent peeling of the oxygen absorbing layer due to volume increase accompanying oxidation of the oxygen scavenger composition. It is preferable to increase the number. Preferably to the solid coating amount of 0.1 to 0.5 g / m ² in the present invention, more preferably as long as 0.2-0.5 g / m ^2.

As a preferred method for producing the oxygen-absorbing multilayer film of the present invention, a method is preferred in which an anchor coating agent is applied to a gas barrier film, dried, and then low density polyethylene is extruded and laminated on the coated surface.
When a protective layer is required outside the gas barrier layer, by a conventionally known laminating method such as dry lamination,
It is preferable that a protective layer is previously laminated on the back side of the gas barrier layer, and the process proceeds to a step of applying an anchor coat agent. As a method of applying an anchor coat agent on a gas barrier film, a direct roll coat system, a direct gravure roll system, a bar coat system can be used, and preferably, a direct roll capable of adjusting the amount of the anchor coat agent applied A coating method or a direct gravure roll method is used. After applying the anchor coat agent, the process proceeds to a drying step for removing the solvent. As the drying device, a hot air jet / drum support type or a hot air jet arch type is used.

After the drying step, a low-density polyethylene resin is extruded and laminated in a molten state on the surface to which the anchor coating agent is applied. For the extrusion lamination of the low-density polyethylene resin, a conventionally known extrusion lamination apparatus including an extruder, a feed block, a T-die, a chill roll, a nip roll, a take-up machine, and the like can be used. When extruding and laminating low-density polyethylene, the resin temperature immediately below the T-die is maintained at about 300 to 325 ° C., and the air gap is set to 50 to 1 in order to increase the adhesiveness.
It is preferable to set it to about 30 mm. The low-density polyethylene resin extruded in a molten state on the anchor coating agent layer formed on the gas barrier layer exhibits high adhesion to the anchor coating agent. This is presumably because the surface of the low-density polyethylene resin extruded in the molten state is oxidized to generate a polar group and chemically bond with the anchor coating agent. The application and drying of the anchor coating agent on the gas barrier layer and the lamination process of the low-density polyethylene layer are preferably performed in a continuous process in consideration of blocking or the like caused by the anchor coating agent.

The laminate comprising the gas barrier layer, the anchor coat agent layer and the low-density polyethylene resin obtained by the above steps may be subsequently laminated by extrusion lamination of the oxygen absorbing layer using a tandem laminator. Alternatively, it may be wound up once in a roll shape and an oxygen absorbing layer may be separately laminated.

Since the low-density polyethylene layer is appropriately oxidized to form a polar group on the surface of the low-density polyethylene layer, the oxygen-absorbing layer may be laminated by extrusion at a relatively low resin temperature of 270 to 300 ° C. Can demonstrate sufficient adhesive strength,
Furthermore, oxidation of the oxygen scavenger dispersed in the oxygen absorbing layer,
Oxidation degradation of the thermoplastic resin due to the oxygen scavenger is reduced, and when the film of the present invention is used as a packaging container, an unpleasant odor due to decomposition of the resin and oxidation of the oxygen scavenger is reduced.

The heat seal layer may be laminated on the oxygen absorbing layer by separate extrusion lamination, or may be laminated together with the oxygen absorbing layer using a co-extrusion laminator. When extruding and laminating the oxygen-absorbing layer, those formed into films in advance may be laminated by various laminating methods to form a heat seal layer.

The oxygen-absorbing multilayer film of the present invention can be used as a material for various packaging containers such as a three-sided sealed bag, a four-sided sealed bag, a bag-like container such as a standing pouch, and a lid material for a gas barrier container. it can. The packaging container using the oxygen-absorbing multilayer film of the present invention for at least a part or all of the container absorbs oxygen in the container, in addition to oxygen slightly entering from outside the container, and stores oxygen in the container. Prevents deterioration due to oxygen and enables long-term storage of stored articles.

The packaging container using the oxygen-absorbing multilayer film of the present invention includes, for example, liquid drinks such as milk, juice, sake, whiskey, shochu, coffee, tea, jelly drink, health drink, seasoning liquid, sauce, Soy sauce, dressing,
Liquid stocks, seasonings such as mayonnaise, miso, grated spices, pasty foods such as jam, cream, chocolate paste, liquid foods such as liquid soups, boiled foods, pickled vegetables, liquid processed foods such as stews, and buckwheat , Udon, Ramen and other raw noodles and boiled noodles, rice before cooking such as milled rice, moisturized rice, unwashed rice, cooked cooked rice, gomoku rice, red rice, processed rice products such as rice porridge, powdered soup, High moisture foods represented by powder seasonings such as soup stock, other solid and solution chemicals such as pesticides and pesticides, liquid and pasty pharmaceuticals, lotions, cosmetic creams, cosmetic emulsions, and hair styling It can store various items such as hair dyes, hair dyes, shampoos, soaps, detergents, etc., and oxygen does not enter from the outside of the container, and oxygen inside the container is absorbed by the oxygen scavenger composition. From the thing Oxidation corrosion is prevented, thereby enabling long-term better quality retention.

[0039]

Examples of the present invention will be described below. Note that the present invention is not limited to these examples. Production Example 1 30 parts by weight of a granular coated iron powder-based oxygen absorber composition obtained by mixing and drying an aqueous solution containing 3 parts by weight of calcium chloride with 100 parts by weight of reduced iron powder having an average particle diameter of 30 μm, Low density polyethylene resin (Mitsui Chemicals Co., Ltd., trade name: Mirason 18SP, melt index = 7 g / 1)
0 minutes (2.16 kg, 190 ° C.), melting point = 110 ° C., 69 parts by weight of calcium oxide and 1 part by weight of calcium oxide are blended and extruded with a 35 mm twin screw extruder, and a net belt with a blower is blended. After cooling with, an oxygen-absorbing compound was obtained through a pelletizer.

Example 1 Biaxially stretched polyethylene terephthalate film (manufactured by Toyobo Co., Ltd .; trade name; Espet T4100;
ET) and aluminum foil are laminated by dry lamination using a urethane adhesive, and PET (12 μm)
/ A gas barrier film made of aluminum foil (9 μm) was produced. Next, this gas barrier film is installed in a direct gravure roll type anchor coating agent coating device, a film feeding device of a tandem type extrusion laminator equipped with a drying device, and an isocyanate anchor coating agent on the aluminum foil side of the gas barrier film. (Toyo Morton Co., Ltd., trade name; Adcoat EL
-443A / hardener EL-443B) in a solid content of 0.5 g
/ M ^2, and after a drying step, a high-pressure low-density polyethylene resin (manufactured by Mitsui Chemicals, Inc., trade name: Mirason 18SP) in a molten state is extruded from an extruder at a resin temperature immediately below the die of 320 ° C. It was extruded and laminated with an air gap of 90 mm. Next, LD of the obtained laminated body
The PE layer and titanium oxide fed from the feeding machine
0% by weight of white high-pressure low-density polyethylene resin (trade name: Mirason 18SP, manufactured by Mitsui Chemicals, Inc.)
Production example 1 from the other extruder between the films
The oxygen-absorbing compound obtained in
Extruded and laminated under the conditions of 0 ° C. and air gap of 90 mm, PET (12 μm) / aluminum foil (9 μm) /
An oxygen-absorbing multilayer film 1 having a constitution of isocyanate-based anchor coating agent (coating amount: solid content 0.5 g / m ² ) / LDPE (20 μm) / oxygen absorbing layer (30 μm) / white LDPE (40 μm) was obtained.

Next, the obtained oxygen-absorbing multilayer film 1
Then, a four-sided seal bag having an inner size of 18 cm × 15 cm was prepared, filled with 200 cc of distilled water, and sealed by heat sealing so that the space inside the bag was about 5 cc. After subjecting this package to heat treatment at 85 ° C. for 30 minutes, 3
It was stored for 1 month in a thermo-hygrostat at 5 ° C. and 60% RH.
Thereafter, the appearance of the packaging bag was observed to investigate the occurrence of delamination of the oxygen-absorbing multilayer film. The bag was opened and the odor of distilled water was investigated. Table 1 shows the results.

Example 2 PET was carried out in the same manner as in Example 1 except that the solid content of the anchor coating agent was adjusted to 0.2 g / m ^2.
(12 μm) / Aluminum foil (9 μm) / Isocyanate anchor coating agent (coating amount: solid content 0.2 g / m ² ) /
An oxygen-absorbing multilayer film 2 having a configuration of LDPE (20 μm) / oxygen absorbing layer (30 μm) / white LDPE (40 μm) was obtained. Next, in the same manner as in Example 1, a packaging bag made of the oxygen-absorbing multilayer film 2 was filled with distilled water, sealed, heat-treated, stored for one month, and then checked for occurrence of delamination and distilled water. An odor study was conducted. Table 1 shows the results.

Comparative Example 1 PET (12 μm) / aluminum foil (9 μm) in the same manner as in Example 1 except that the anchor coating agent was not applied.
An oxygen-absorbing multilayer film 3 having a configuration of / LDPE (20 μm) / oxygen absorbing layer (30 μm) / white LDPE (40 μm) was obtained. Next, in the same manner as in Example 1, a packaging bag made of the oxygen-absorbing multilayer film 3 was filled with distilled water,
After sealed and heat-treated and stored for one month, the presence or absence of delamination and the odor of distilled water were investigated. Table 1 shows the results
Shown in

Comparative Example 2 Using a tandem laminator, a linear low-density polyethylene film (trade name; TUX-TC; abbreviated as LLDPE film) manufactured by Tocelo Co., Ltd.
On the top, the oxygen-absorbing compound obtained in Production Example 1 was extruded and laminated at a resin temperature of 320 ° C. directly below the die with an air gap of 90 mm to form an oxygen-absorbing layer, and then white LDPE was extruded from the other extruder into a resin immediately below the die. Temperature 32
It was extruded and laminated at 0 ° C. with an air gap of 90 mm and wound up by a winder.

Next, the aluminum foil side of the gas barrier film having the structure of PET / aluminum foil and the LL
The DPE film side is adhered by dry lamination using a urethane-based adhesive, and has a structure of PET (12 μm) / aluminum foil (9 μm) / LLDPE film (30 μm) / oxygen absorbing layer (30 μm) / white LDPE (40 μm). An oxygen-absorbing multilayer film 4 was obtained. Next, in the same manner as in Example 1, a packaging bag made of the oxygen-absorbing multilayer film 4 was filled with distilled water, sealed, heat-treated, stored for one month, and then checked for occurrence of delamination, and distilled water. An odor study was conducted. Table 1 shows the results.

Comparative Example 3 The same procedure as in Comparative Example 2 was carried out except that the conditions for laminating the oxygen-absorbing layer by extrusion were set such that the resin temperature immediately below the die was 280 ° C.
(12 μm) / aluminum foil (9 μm) / LLDPE film (30 μm) / oxygen absorbing layer (30 μm) / white LDP
An oxygen-absorbing multilayer film 5 having a configuration of E (40 μm) was obtained. Next, in the same manner as in Example 1, the packaging bag made of the oxygen-absorbing multilayer film 5 was filled with distilled water, sealed, heat-treated, and stored for one month.
And odor investigation of distilled water was carried out. Table 1 shows the results.

[0047]

[Table 1] Presence or absence of delamination (peeled part) Off-flavor in container ────────────────────────────────── ── Example 1 None ○ Example 2 None ○ Comparative Example 1 Yes (aluminum foil / LDPE) ○ Comparative Example 2 None × (resin odor and iron odor) Comparative Example 3 Yes (LLDPE / oxygen absorbing layer) ○ ───評 価 Evaluation of off-flavor in container ○: No abnormality △; Slight off-odor ×: Clear Has a bad smell

As is evident from Table 1, the oxygen-absorbing multilayer films of the present invention shown in Examples 1 and 2 maintain their appearance without delamination even after filling and storing the contents. Also, when the container was opened, there was no off-flavor.
On the other hand, in Comparative Example 1, since the gas barrier layer was not bonded via the anchor coat agent, the appearance was observed after storage for one month from the heat treatment, and the aluminum foil and the low-density polyethylene layer were partially peeled off. I was In Comparative Examples 2 and 3, no delamination of the gas barrier layer was observed because the gas barrier layer was adhered by dry lamination. However, in Comparative Example 2, the oxygen absorption layer was extruded at a high temperature. A resin odor due to oxidative deterioration of the LDPE constituting the layer and an oxidized odor of the iron powder constituting the oxygen scavenger composition were generated. In Comparative Example 3, since the oxygen absorbing layer was extruded at a low temperature, there was no off-odor as in Comparative Example, but the adhesive strength with the LLDPE film serving as the base material was weak, and the LLDPE film and the oxygen absorbing layer were stored after storage for one month. Partially peeled off.

[0049]

The oxygen-absorbing multilayer film of the present invention and the oxygen-absorbing multilayer film produced by the method of the present invention are a low-density polyethylene resin having a gas barrier layer comprising a high-pressure low-density polyethylene via an anchor coat agent. It is strongly bonded to the layer and the oxygen absorbing layer, and has excellent interlayer adhesive strength and excellent odorlessness. The packaging container comprising the oxygen-absorbing multilayer film of the present invention retains its initial appearance even when stored for a long period of time, and does not give off odor in the packaging container. Enable.

 ────────────────────────────────────────────────── ─── Continuing on the front page F term (reference) 3E067 AA03 AA04 AA11 AB19 AB21 AB26 AB28 AB81 AB96 BA02A BA12A BB14A BB15A BB22A BB25A BB26A BC07A CA03 CA04 CA24 EA08 EA09 EE25 EE32 EE35 GB13 AE10 ABKA AR00B AR00D BA04 BA05 BA07 BA10A BA10D BA10E BA26 CA09B CB01 CB03 DA01 GB23 GB66 JB16A JC00 JD02D JD03A JD14 JD14B JK06 JL11A

Claims (5)

[Claims] 1. A heat sealing layer made of a thermoplastic resin having oxygen permeability, an oxygen absorbing layer made of a thermoplastic resin in which an oxygen scavenger is dispersed, a low density polyethylene resin layer made of a high density low density polyethylene resin, and an anchor coat. An oxygen-absorbing multilayer film comprising an agent layer and a gas barrier layer. 2. The oxygen-absorbing multilayer film according to claim 1, wherein the anchor coating agent is an isocyanate-based anchor coating agent. 3. The oxygen-absorbing multilayer film according to claim 1, wherein the coating amount of the anchor coating agent is 0.1 to 0.5 g / m ² in solid content. 4. A packaging container comprising the oxygen-absorbing multilayer film according to claim 1 or a part of the packaging container. 5. A heat seal layer made of a thermoplastic resin having oxygen permeability, an oxygen absorption layer made of a thermoplastic resin in which an oxygen scavenger is dispersed, a low density polyethylene resin layer made of a high density low density polyethylene resin, and an anchor coat. A method for producing a multilayer film comprising a laminated structure of an agent layer and a gas barrier layer, comprising laminating a high-pressure low-density polyethylene resin in a molten state on an anchor coating agent applied to the surface of a gas barrier layer. A method for producing an oxygen-absorbing multilayer film.