JP2024051983A - Oxygen-absorbing packaging material for packaging container corresponding to microwave oven - Google Patents

Abstract

PURPOSE: To provide an oxygen-absorbing packaging material for a packaging container corresponding to a microwave oven which radiates a little amount of smell, is excellent in microwave oven heating resistance, suppresses permeation of oxygen gas from the outside, suppresses deterioration due to oxygen and odor change of a content by absorbing oxygen in a content storage space, and has excellent balance among aroma retention property, content-resistant properties, inter-layer adhesiveness, heat-sealability, oxygen absorbing property, microwave oven resistance, odor change resistance of a liquid content and high drop impact resistance, and to provide an oxygen-absorbing packaging container corresponding to a microwave oven.

SOLUTION: An oxygen-absorbing packaging material for a packaging container corresponding to a microwave oven includes at least a base material layer, a printing ink layer, a specific printing ink shielding resin layer, an oxygen absorbing adhesive agent layer comprising a specific oxygen absorbing adhesive agent, a specific anti-oxydant shielding resin layer, and a specific sealant layer in this order.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to an oxygen-absorbing packaging material for microwave-compatible packaging containers that generates little odor, inhibits the permeation of oxygen gas from the outside, inhibits deterioration of the contents due to oxygen by absorbing oxygen in the content storage space, and has an excellent balance of aroma retention, content resistance, interlayer adhesion, heat sealability, high drop impact resistance, oxygen absorption performance, microwave resistance, amount of odor generated, and resistance to odor and taste changes of liquid contents, and is suitable for filling and packaging, and to a microwave-compatible oxygen-absorbing packaging container made from the oxygen-absorbing packaging material for microwave-compatible packaging containers.

Conventional packaging methods for preventing the deterioration of contents such as food, medical products, chemical products, and cosmetics due to oxygen have included the use of packaging materials with high oxygen barrier properties, gas replacement of the content storage section with an inert gas such as nitrogen gas, and the inclusion of an oxygen scavenger packaged in reduced iron powder or the like. However, there are problems such as insufficient performance, increased packaging costs, increased garbage as waste, only functioning in moist environments, and the risk of accidental ingestion.
Conventional oxygen-absorbing laminates or oxygen-absorbing packaging materials contain an oxygen absorbent, which includes an organic compound or a metal-based oxygen absorbent such as iron powder, and the oxygen absorbent itself oxidizes to absorb oxygen in the content storage space.

Furthermore, in many cases, the oxygen absorbing layer containing the oxygen absorbent is disposed in a layer closer to the contents-accommodating space, for example, in a layer adjacent to a sealant layer, in order to increase the oxygen absorption efficiency.
However, since the sealant layer is the innermost layer that comes into contact with the contents, it generally contains various additives such as antioxidants, lubricants, and antiblocking agents to impart various functionalities, and these additives tend to migrate to the adjacent oxygen absorbing layer.
As a result, when the oxygen absorber is an organic compound, the additive, particularly the antioxidant, that migrates to the oxygen absorbing layer tends to inhibit the oxidation reaction of the oxygen absorber, resulting in a decrease in the oxygen absorption efficiency.

Furthermore, when the oxygen absorber is a metal-based oxygen absorber, the above-mentioned inhibition is unlikely to occur. However, the oxygen absorbing layer is severely colored by the oxygen absorber, and the color of the packaging material is so dark that the contents cannot be visually confirmed, and inspection of the contents using a metal detector or the like is impossible. Heating in a microwave oven is also impossible, and there is a concern that rust may occur due to moisture.
Furthermore, Patent Document 1 proposes a packaging material for medical use that has oxygen absorbing properties and can be boiled or retorted, but the sealant layer is made of a special highly heat-resistant polyethylene resin that is difficult to obtain, and there is a problem with its versatility.

Patent Document 2 also describes the development of a packaging material that uses a resin that has oxygen absorbing properties and emits little odor, but this resin is polycyclododecene, which is insoluble in polar solvents and does not have active hydrogen groups, making it difficult to use as an adhesive raw material for packaging materials made of laminates.

Patent Document 3 proposes a laminating adhesive made of a resin that uses methyltetrahydrophthalic acid as a raw material with oxygen absorbing properties, but it has the disadvantage of being unstable due to its low oxygen absorbing properties.

Patent Document 4 describes an oxygen-absorbing resin that is a thermoplastic resin having a repeating unit composed of a saturated five-membered ring having a substituent containing a carbon-carbon double bond and a -CH=CH- group linking the saturated five-membered rings. However, this resin has drawbacks such as being difficult to use due to its poor solubility in solvents and emitting a strong odor.

Japanese Patent No. 6403999 Patent No. 5873770 Patent No. 5671816 Japanese Patent No. 6505699

The object of the present invention is to provide an oxygen-absorbing packaging material for microwave-compatible packaging containers that generates little odor, has excellent resistance to microwave heating, inhibits the permeation of oxygen gas from the outside, inhibits deterioration and odor/taste changes of the contents due to oxygen by absorbing oxygen in the contents storage space, and has an excellent balance of aroma retention, resistance to contents, interlayer adhesion, heat sealability, oxygen absorption, microwave resistance, resistance to odor/taste changes of liquid contents, and high drop impact resistance, and a microwave-compatible oxygen-absorbing packaging container.

（式中、ａ～ｅの各々は１以上の数、ｆは０以上の数であり、Ｒ¹、Ｒ²、Ｒ³、Ｒ⁴、Ｒ⁵の各々は炭素数１以上の有機基である。また、Ｒ¹、Ｒ²、Ｒ³、Ｒ⁴、Ｒ⁵の各々は、少なくともアルキレンおよび／またはフェニレン構造を含むことができ、多価アルコール類、ポリオレフィンポリオール、ポリエーテルポリオール、ポリエステルポリオール、ポリカーボネートポリオール、ポリ（メタ）アクリル酸エステルポリオール、フェノキシ樹脂、およびこれらのウレタン鎖伸長ポリオールからなる群から選ばれる１種または２種以上に由来する構造を含むことができる。）
６．上記１～５の何れかに記載の電子レンジ対応酸素吸収性包装材からなることを特徴と
する、電子レンジ対応酸素吸収性包装容器。
７．上記１～５の何れかに記載の電子レンジ対応酸素吸収性包装材からなることを特徴とする、電子レンジ対応酸素吸収性包装袋。 Therefore, in order to solve the above-mentioned problems, the inventors have discovered that an oxygen-absorbing packaging material for microwave-compatible packaging containers, which comprises, in this order, at least a base layer, a printed ink layer, a specific printed ink-shielding resin layer, an oxygen-absorbing adhesive layer made of a specific oxygen-absorbing adhesive, a specific antioxidant-shielding resin layer, and a specific sealant layer, can solve the above-mentioned problems.
1. A microwaveable oxygen-absorbing packaging material having, in this order, at least a base layer, a printing ink layer, a printing ink-shielding resin layer, an oxygen-absorbing adhesive layer, an antioxidant-shielding resin layer, and a sealant layer,
The substrate layer and/or the printing ink shielding resin layer includes a metal oxide vapor deposition layer on the surface on the sealant layer side,
The printing ink shielding resin layer includes a polyester-based resin layer,
The oxygen-absorbing adhesive layer is a layer made of an oxygen-absorbing adhesive composition containing at least an oxygen-absorbing compound and an oxidation-promoting catalyst,
The antioxidant-shielding resin layer contains a polyester resin or a polyamide resin,
The sealant layer contains a polyolefin resin and an antioxidant,
The oxygen absorbing compound has one or more unsaturated five-membered rings,
Any bond between the five carbon atoms constituting the unsaturated five-membered ring is a carbon-carbon double bond;
A monovalent and/or divalent or higher electron-donating organic group 1 is bonded to the unsaturated five-membered ring;
When there is one unsaturated five-membered ring, the five-membered ring or the organic group 1 has a functional group having an active hydrogen or a group in which the active hydrogen of the functional group having an active hydrogen is substituted with a monovalent organic group 2,
A microwave-safe oxygen-absorbing packaging material, characterized in that when there are two or more unsaturated five-membered rings, the unsaturated five-membered rings are bonded to each other via a divalent or higher organic group 2 that replaces the active hydrogen of the active hydrogen group on each of the five-membered rings or the organic group 1.
2. The oxygen-absorbing adhesive composition further contains a modifier,
2. The microwave-safe oxygen-absorbing packaging material according to 1 above, wherein the modifying agent contains an isocyanate compound and/or a hydroxyl group-containing compound.
3. The microwave-safe oxygen-absorbing packaging material according to the above item 1 or 2, characterized in that the polyolefin resin is a polypropylene resin.
4. The substrate layer and/or the printing ink shielding resin layer further includes a sol-gel coating layer on the surface of the metal oxide vapor deposition layer facing the sealant layer,
4. The microwave-compatible oxygen-absorbing packaging material according to any one of 1 to 3 above, wherein the sol-gel coating layer is a layer formed from a resin composition containing a metal alkoxide, a water-soluble polymer, a sol-gel catalyst, water, an organic solvent, and the like.
5. The microwave-safe oxygen-absorbing packaging material according to any one of 1 to 4 above, wherein the oxygen-absorbing compound contains one or more compounds selected from the group consisting of compounds represented by the following formulas (1) to (5):

(In the formula, each of a to e is a number of 1 or more, f is a number of 0 or more, and each of R ¹ , R ² , R ³ , R ⁴ , and R ⁵ is an organic group having 1 or more carbon atoms. Each of R ¹ , R ² , R ³ , R ⁴ , and R ⁵ may contain at least an alkylene and/or phenylene structure, and may contain a structure derived from one or more selected from the group consisting of polyhydric alcohols, polyolefin polyols, polyether polyols, polyester polyols, polycarbonate polyols, poly(meth)acrylic acid ester polyols, phenoxy resins, and urethane chain-extended polyols thereof.)
6. A microwave-safe, oxygen-absorbing packaging container, comprising the microwave-safe, oxygen-absorbing packaging material according to any one of 1 to 5 above.
7. A microwave-safe, oxygen-absorbing packaging bag, comprising the microwave-safe, oxygen-absorbing packaging material according to any one of 1 to 5 above.

According to the present invention, it is possible to obtain an oxygen-absorbing packaging material for microwave-compatible packaging containers and a microwave-compatible oxygen-absorbing packaging container that emits little odor, has excellent resistance to microwave heating, inhibits the permeation of oxygen gas from the outside, inhibits deterioration and odor/taste changes of the contents due to oxygen by absorbing oxygen in the content storage space, and has an excellent balance of aroma retention, resistance to contents, interlayer adhesion, heat sealability, oxygen absorption, microwave resistance, resistance to odor/taste changes of liquid contents, and resistance to drop impact.

The oxygen-absorbing packaging material for a microwave oven-safe packaging container of the present invention can shorten the packaging process, reduce costs, and make the packaging container lighter.
The microwave-compatible oxygen-absorbing packaging container of the present invention does not require the inclusion of an oxygen scavenger as was conventionally done, thereby eliminating the risk of accidental ingestion of the oxygen scavenger and reducing waste consisting of oxygen scavenger. Furthermore, since less odor is emitted from the container, changes in the odor and taste of the contents can be minimized.

1 is a cross-sectional view showing an example of the layer structure of an oxygen-absorbing packaging material for a microwave-safe packaging container of the present invention. FIG. 2 is a cross-sectional view showing another example of the layer structure of the oxygen-absorbing packaging material for microwave-safe packaging containers of the present invention. FIG. 2 is a cross-sectional view showing another example of the layer structure of the oxygen-absorbing laminate for a microwave-compatible packaging container of the present invention. FIG. 2 is a cross-sectional view showing another example of the layer structure of the oxygen-absorbing laminate for a microwave-compatible packaging container of the present invention. 1 is an external view showing a microwave-safe oxygen-absorbing pouch, which is one embodiment of the microwave-safe oxygen-absorbing packaging container of the present invention. FIG. 1 is a cross-sectional view of a microwave-safe oxygen-absorbing packaging container according to one embodiment of the present invention, which is a microwave-safe lid part and a microwave-safe bottom part. FIG. 1 is an external view showing a microwave-compatible, oxygen-absorbing retort pouch, which is one embodiment of the microwave-compatible, oxygen-absorbing packaging container of the present invention.

The present invention will be described in more detail below. The following description of the constituent elements is an example of an embodiment of the present invention, and the present invention is not limited to these contents as long as it does not deviate from the gist of the present invention.
In the present invention, the terms film and sheet have the same meaning.
The boiling/retort treatment conditions in the present invention refer to treatment conditions in which the material is heated at 90 to 135° C. under 1 to 3 atmospheric pressure.
Hereinafter, the oxygen-absorbing packaging material for microwave-compatible packaging containers, the microwave-compatible oxygen-absorbing packaging containers, the microwave-compatible oxygen-absorbing lid parts, the microwave-compatible oxygen-absorbing bottom parts, and the microwave-compatible oxygen-absorbing pouch will also be abbreviated to packaging material, oxygen-absorbing packaging material, container, oxygen-absorbing packaging container, oxygen-absorbing lid part, oxygen-absorbing bottom part, and oxygen-absorbing pouch.

<<Oxygen-absorbing packaging material for microwave-safe packaging containers>>
The oxygen-absorbing packaging material for microwave-compatible packaging containers of the present invention has a layer structure including, in this order, at least a base layer, a printed ink layer, a specific printed ink-shielding resin layer, an oxygen-absorbing adhesive layer consisting of a specific oxygen-absorbing adhesive, a specific antioxidant-shielding resin layer, and a specific sealant layer.
The substrate layer or the printing ink blocking resin layer includes a resin layer and a metal oxide vapor deposition layer, and the metal oxide vapor deposition layer is included on the surface of the resin layer facing the sealant layer.
The printing ink-blocking resin layer, the oxygen-absorbing adhesive layer, and the antioxidant-blocking resin layer can be adjacent to each other.
In a microwave-safe oxygen-absorbing packaging container made using an oxygen-absorbing packaging material for a microwave-safe packaging container, the metal oxide vapor deposition layer is positioned outside the oxygen-absorbing adhesive layer, and the sealant layer is heat-sealed to form a sealed container.
By positioning the metal oxide vapor deposition layer on the outer side of the oxygen-absorbing adhesive layer, it is possible to inhibit oxygen from permeating through the packaging material from the outside to the inside of the oxygen-absorbing packaging container.
Furthermore, when the metal oxide vapor deposition layer is a transparent vapor deposition film made of a specific metal oxide such as alumina, the contents inside the oxygen-absorbing packaging container can be visually confirmed, the contents can be inspected using a metal detector, and the contents can be heated in a microwave oven.

The oxygen-absorbing adhesive layer can absorb oxygen attempting to enter the content-containing space from outside the oxygen-absorbing packaging container and oxygen present in the content-containing space, thereby reducing the oxygen concentration in the content-containing space.
Furthermore, since the oxygen-absorbing adhesive layer is not adjacent to the sealant layer and the antioxidant-shielding resin layer is present between the oxygen-absorbing adhesive layer and the sealant layer, the various additives contained in the sealant layer are prevented from migrating into the oxygen-absorbing adhesive layer, and a decrease in the oxygen absorption efficiency of the oxygen-absorbing adhesive layer is prevented.

The migration of printing ink components such as metal oxide pigments contained in the printing ink layer, particularly titanium oxide contained in white ink, to the oxygen-absorbing adhesive layer is inhibited by the printing ink-blocking resin layer that exists between them, thereby inhibiting a decrease in the oxygen absorption efficiency of the oxygen-absorbing adhesive layer.

The oxygen-absorbing adhesive layer is a layer formed from an oxygen-absorbing adhesive composition that contains an oxygen-absorbing compound, which is an organic compound, and an oxidation-promoting catalyst. Since the layer does not contain a metallic oxygen absorbent such as iron powder, there is no dark coloring due to the metallic oxygen absorbent, and there is no risk of rusting due to moisture.

The sealant layer contains a heat-sealable resin, and preferably contains a heat-sealable resin having high heat resistance and resistance to oxidation and deterioration in order to withstand heating and sterilization treatment in a microwave oven, and also preferably contains an antioxidant, etc.
Specifically, the sealant layer preferably contains a polypropylene-based resin and has a softening point of 120° C. or higher and 170° C. or lower.

The oxygen-absorbing packaging material for microwave-safe packaging containers of the present invention is preferably transparent, and more preferably has a total light transmittance of 80 or more and a haze value of 40 or less.

The oxygen-absorbing packaging material for microwave-safe packaging containers can further include various functional layers having various functions, as necessary. Examples of functional layers include an auxiliary barrier layer, an aroma-retaining layer, a light-shielding layer, a reinforcing layer, and a sol-gel coating layer.

Furthermore, an adhesive layer for improving interlayer adhesion may be included between or within each layer. This adhesive layer may be an adhesive layer using a general-purpose adhesive that does not absorb oxygen.
An anchor coat layer may also be included adjacent to the oxygen absorbing adhesive layer or adhesive layers.

[Contents]
Examples of contents that can be stored in the microwave-compatible, oxygen-absorbing packaging container of the present invention include, but are not limited to, foods such as coffee beans, tea leaves, cheese, snacks, rice crackers, fresh and semi-fresh confectioneries, fruits, nuts, vegetables, fruits, fish and meat products, paste products, dried fish, smoked foods, tsukudani (food boiled in soy sauce), raw rice, cooked rice, rice cakes, baby foods, jams, mayonnaise, ketchup, edible oils, dressings, sauces, spices, dairy products, pet foods, etc.; beverages such as beer, wine, fruit juice, green tea, and coffee; medicines, cosmetics, shampoos and rinses, detergents, metal parts, electronic parts, etc.

<Base layer>
The substrate layer has a resin layer, and the material of the resin layer of the substrate layer can be a general known resin film having excellent mechanical, physical, chemical, and other properties, particularly strength, toughness, and heat resistance. Furthermore, various paper substrates can be used, and a resin film and a paper substrate can be used in combination.
The substrate layer may be composed of one layer or two or more layers. When composed of two or more layers, the substrate layer may be composed of two or more layers having the same or different compositions and thicknesses, or may be composed of two or more layers laminated by any lamination means.

The substrate layer may also include a metal oxide vapor deposition layer. In this case, it is preferable that the substrate layer includes the metal oxide vapor deposition layer on the surface of the resin layer facing the sealant layer.

The thickness of the base layer can be set as appropriate by those skilled in the art, but in order to provide the packaging material with appropriate strength and stiffness, it is preferably 5 μm to 100 μm, more preferably 10 μm to 50 μm, and even more preferably 12 to 25 μm.

Specific examples of the resin film for the base layer include resin films made of tough thermoplastic resins such as polyester-based resins such as polyethylene terephthalate (PET) and polyethylene naphthalate, polyolefin-based resins such as polypropylene, polyamide-based resins such as nylon, polyaramid-based resins, polycarbonate-based resins, polyacetal-based resins, fluorine-based resins, and others.
The resin film may be either an unstretched film or a uniaxially or biaxially stretched film.
Among the above, a biaxially oriented PET film and a biaxially oriented polyamide resin film are preferably used.

If necessary, plastic compounding agents and additives such as lubricants, crosslinking agents, antioxidants, UV absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, and pigments may be added to the resin film used for the base layer for the purpose of improving or modifying processability, heat resistance, weather resistance, mechanical properties, dimensional stability, oxidation resistance, slipperiness, release properties, flame retardancy, mildew resistance, electrical properties, strength, and the like. The amount of these additives may be arbitrarily added depending on the purpose as long as it does not adversely affect other performance properties.
The substrate layer can be laminated with other layers via an adhesive layer. Furthermore, if necessary, in order to strengthen the adhesive strength between the substrate layer and the adhesive layer, the surface of the substrate layer that contacts the adhesive can be previously subjected to physical surface treatment such as corona discharge treatment, ozone treatment, plasma treatment, glow discharge treatment, sandblasting treatment, etc., or chemical surface treatment such as oxidation treatment using chemicals.

The paper base material can provide shapeability, flex resistance, rigidity, etc., and for example, a strong sizing bleached or unbleached paper base material for a paper layer, or a paper base material such as pure white roll paper, kraft paper, paperboard, coated paper, processed paper, milk base paper, etc. can be used.
The paper base material preferably has a basis weight of about 30 g/m ² to 600 g/m ² , and more preferably has a basis weight of about 50 g/m ² to 450 g/m ² .

<Printing ink layer>
The printed ink layer may consist of only a solid layer, or may consist of a printed ink pattern layer and a printed ink solid layer, and may be provided over the entire surface to be printed, or may be provided only on a part of it.
The printed ink layer may also visually indicate design patterns such as letters, numbers, figures, symbols, pictures, designs, etc. for decoration, indication of contents, indication of expiration date, indication of manufacturer, seller, etc., or for the purpose of imparting aesthetic appeal.
The printed ink layer is preferably formed on the surface of the metal oxide vapor deposition layer by a printing method such as gravure printing or flexographic printing.
The printing ink layer may contain various pigments, for example, metal oxide pigments.
Metal oxide pigments usually tend to inhibit the oxygen absorbing performance of the organic oxygen absorbing compound contained in the oxygen absorbing layer, but the oxygen absorbing laminate of the present invention can be used without problems because it has a printing ink component shielding resin layer.
A specific example of the metal oxide pigment is a titanium oxide white pigment.
The thickness of the printed ink layer can be appropriately set by a person skilled in the art, but in order to impart appropriate durability to the printed ink layer, the thickness is preferably 0.5 g/mm ² to 5 g/mm ² , more preferably 1 g/mm ² to 4 g/mm ² , and even more preferably 2 g/mm ² to 3 g/mm ² .

<Printing ink shielding resin layer>
The printing ink shielding resin layer is a resin layer for suppressing the migration of metal oxide pigments in the printing ink components, particularly titanium oxide contained in white ink, from the printing ink layer to the oxygen absorbing adhesive layer.
The migration of printing ink components such as metal oxide pigments contained in the printing ink layer to the oxygen-absorbing adhesive layer is suppressed by the printing ink-blocking resin layer present in between, thereby suppressing a decrease in the oxygen absorption efficiency of the oxygen-absorbing adhesive layer.

The printing ink blocking resin layer may be composed of one layer, or two or more layers having the same or different composition and thickness and laminated by any lamination means.
The printing ink blocking resin layer may further include a metal oxide vapor deposition layer, in which case it is preferable that the printing ink blocking resin layer includes the metal oxide vapor deposition layer on the surface facing the sealant layer.
The thickness of the printing ink shielding resin layer can be appropriately set by a person skilled in the art, but for the purpose of imparting appropriate strength and stiffness to the laminate, it is preferably 5 μm to 100 μm, more preferably 10 μm to 50 μm, and even more preferably 12 to 25 μm.

The resin contained in the printing ink shielding resin layer is not particularly limited as long as it can suppress the migration of metal oxide pigments, and any commonly known and commonly used resin can be used.
Specific examples of resins for the printing ink shielding resin layer include polyester-based resins such as polyethylene terephthalate (PET) and polyethylene naphthalate, polyamide-based resins such as nylon, and polyolefin-based resins such as polypropylene.
Among the above, polyester-based resins and polyamide-based resins are preferred because they are excellent in flexibility, puncture resistance, pinhole resistance, and the like.
The film made of the above resin may be either an unstretched film or a uniaxially or biaxially stretched film.
Among the above, a biaxially oriented PET film and a biaxially oriented nylon film are preferably used.

If necessary, plastic compounding agents and additives such as lubricants, crosslinking agents, antioxidants, UV absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, and pigments can be added to the resin film used in the printing ink shielding resin layer for the purpose of improving or modifying processability, heat resistance, weather resistance, mechanical properties, dimensional stability, oxidation resistance, slipperiness, release properties, flame retardancy, mold resistance, electrical properties, strength, etc., and the amount of these additives can be freely selected depending on the purpose as long as it does not adversely affect other properties.

The printing ink shielding resin layer may be formed by adhering a pre-prepared resin film for the printing ink shielding resin layer via an adhesive or the like, or may be formed by melt extrusion in which a molten resin composition is laminated on another layer.
The resin film may be produced by melt-extruding one or more resin compositions and forming a film by an inflation method, or by extrusion using a T-die molding or the like, melt-extruding onto a roll and constricting the film to form a resin film. Here, it is preferable to subject one or both sides of the produced resin film to a corona treatment before bonding and laminating.
When forming a printing ink-blocking resin layer by melt extrusion, the resin composition is melted, (co)extruded, and poured onto the layer to be laminated, and the printing ink-blocking resin layer can be formed by an extrusion method using a T-die molding method using a feed block method or a multi-manifold method.
In either method, a single printing ink shielding resin layer or multiple printing ink shielding resin layers using resin compositions of the same or different compositions can be prepared.

The printing ink shielding resin layer can be laminated to other layers via an adhesive layer or an oxygen absorbing adhesive layer. Furthermore, if necessary, in order to strengthen the adhesive strength between the printing ink shielding resin layer and the adhesive layer or the oxygen absorbing adhesive layer, the surface of the printing ink shielding resin layer that contacts the adhesive layer or the oxygen absorbing adhesive layer can be previously subjected to physical surface treatment such as corona discharge treatment, ozone treatment, plasma treatment, glow discharge treatment, sandblasting treatment, etc., or chemical surface treatment such as oxidation treatment using chemicals.
When the printing ink blocking resin layer contains a metal oxide vapor deposition layer, it is preferable to laminate a resin film for the printing ink blocking resin layer having a pre-prepared metal oxide vapor deposition layer by adhesion via an adhesive or the like.

The resin film of the printing ink shielding resin layer on which the metal oxide vapor deposition layer is vapor deposited may be any of the above-mentioned resin films or other resin films.
Examples of the resin film of the printing ink shielding resin layer on which the metal oxide vapor deposition layer is vapor-deposited include polyester-based resin films such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT); polyamide-based resin films such as various nylons; polyolefin films such as polyethylene-based resins, polypropylene-based resins, cyclic polyolefin resins, polystyrene-based resins, acrylonitrile-styrene copolymers (AS resins), acrylonitrile-butadiene-styrene copolymers (ABS resins), and polybutene resin films; and resin films made of resins such as polyvinyl chloride-based resins, polycarbonate-based resins, polyimide-based resins, polyamideimide-based resins, polyarylphthalate resins, silicone-based resins, polysulfone-based resins, polyphenylene sulfide-based resins, polyethersulfone-based resins, polyurethane-based resins, cellulose-based resins, poly(meth)acrylic resins, polyvinylidene chloride films, acetal-based resin films, and fluorine-based resins.
Among the above resins, it is particularly preferable to use a resin film made of a polyester resin, a polyamide resin, or a polypropylene resin.

The resin film of the printing ink shielding resin layer on which the metal oxide vapor deposition layer is deposited may be a resin film made of an oxygen barrier resin, a water vapor barrier resin, a highly aromatic resin, or the like.
Examples of oxygen barrier resins include polyvinylidene chloride resins (PVDC), polyester resins, polyamide resins (particularly aromatic polyamides such as nylon MXD6), ethylene-vinyl alcohol copolymers (EVOH) having an ethylene content of 25 mol % to 50 mol % obtained by fully saponifying an ethylene-vinyl acetate copolymer (vinyl acetate is approximately 79 wt % to 92 wt %), polyvinyl alcohol, polyacrylonitrile, and the like.
The thickness of the resin film of the printing ink shielding resin layer onto which the metal oxide vapor deposition layer is vapor deposited is arbitrary, but is preferably 0.5 μm to 100 μm, more preferably 1 μm to 100 μm, even more preferably 5 μm to 100 μm, particularly preferably 10 μm to 50 μm, and most preferably 12 to 25 μm.
When the metal oxide vapor-deposited layer is adhered to another resin film, it can be laminated by adhering via an oxygen-absorbing adhesive composition or adhesive layer.

<Metal oxide deposition layer>
The metal oxide vapor deposition layer is a layer contained in the substrate layer and/or the printing ink blocking resin layer. When the metal oxide vapor deposition layer is contained in both the substrate layer and the printing ink blocking resin layer, the metal oxide vapor deposition layer contained in each layer may have the same composition and layer structure or may have a different composition and layer structure.
By being located outside the oxygen-absorbing adhesive layer in a microwave-compatible oxygen-absorbing packaging container, the metal oxide vapor deposition layer can suppress the transmission of oxygen from the outside of the container to the content storage section inside the container, thereby enhancing the effect of the oxygen-absorbing adhesive layer in reducing the oxygen concentration in the content storage space.

The metal oxide vapor deposition layer can contain one or more metal oxides.
In addition, the metal oxide vapor deposition layer can improve the barrier properties not only against oxygen but also against water vapor, the light-shielding properties against sunlight, and the aroma retention of the contents, and metal oxide vapor deposition layers suitable for each effect may be used in combination.

Among various inorganic vapor deposition layers, metal oxide vapor deposition layers are preferred because they have the following advantages: they have excellent barrier properties against oxygen gas, water vapor, light blocking properties, transparency, and aroma retention; they are environmentally friendly when it comes to disposing of the container; the contents can be inspected using a metal detector, they can be heated in a microwave oven, and there is no risk of rust due to moisture.

The metal oxide vapor deposition layer is preferably formed by vapor deposition on a resin film, and more preferably formed by vapor deposition on a resin film that has excellent mechanical, physical, chemical and other properties such that it can withstand the vapor deposition processing environment, and that has particularly high strength, toughness and heat resistance.
The resin film on which the metal oxide vapor deposition layer is vapor-deposited may be the resin film of the substrate layer and/or the printing ink blocking resin layer, or it may be a resin film different from the substrate layer and/or the printing ink blocking resin layer.

Furthermore, the resin film including the metal oxide vapor deposition layer has an acid permeability measured in accordance with JIS K7126 under an environment of a temperature of 23° C. and a humidity of 90% RH of preferably 3.0 cc/ ^m2 ·atm·day or less, more preferably 2.0 cc/ ^m2 ·atm·day or less, and even more preferably 1.0 cc/ ^m2 ·atm·day or less. If the oxygen permeability satisfies the above numerical range, the intrusion of oxygen from the outside of the package into the content-accommodating portion inside the package can be sufficiently suppressed.
Furthermore, the resin film including the metal oxide vapor deposition layer has a water vapor permeability measured in accordance with JIS K7129 under an environment of a temperature of 40° C. and a humidity of 100% RH of preferably 3.0 g/ ^m2 ·day or less, more preferably 2.0 g/ ^m2 ·day or less, and even more preferably 1.5 g/ ^m2 ·day or less. If the water vapor permeability is within the above numerical range, the intrusion of water vapor from the outside of the package into the content storage section inside the package can be sufficiently suppressed.

Examples of the resin film on which the metal oxide deposition layer is deposited include polyester-based resin films such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), polyamide-based resin films such as various nylons, polyolefin films such as polyethylene resins, polypropylene resins, cyclic polyolefin resins, polystyrene resins, acrylonitrile-styrene copolymers (AS resins), acrylonitrile-butadiene-styrene copolymers (ABS resins), and polybutene resin films, polyvinyl chloride resins, polycarbonate resins, polyimide resins, polyamideimide resins, polyarylphthalate resins, silicone resins, polysulfone resins, polyphenylene sulfide resins, polyethersulfone resins, polyurethane resins, cellulose resins, poly(meth)acrylic resins, polyvinylidene chloride films, acetal resin films, and resin films made of fluorine-based resins, but are not limited to these examples.
Among the above resin films, resin films made of polyester-based resin, polyamide-based resin, and polypropylene-based resin are particularly preferred.

The resin film on which the metal oxide vapor-deposited layer is deposited may be a resin film made of an oxygen barrier resin, a water vapor barrier resin, a highly aromatic resin, or the like.
Examples of oxygen barrier resins include polyvinylidene chloride resins (PVDC), polyester resins, polyamide resins (particularly aromatic polyamides such as nylon MXD6), ethylene-vinyl alcohol copolymers (EVOH) having an ethylene content of 25 mol % to 50 mol % obtained by fully saponifying an ethylene-vinyl acetate copolymer (vinyl acetate is approximately 79 wt % to 92 wt %), polyvinyl alcohol, polyacrylonitrile, and the like.

The thickness of the resin film on which the metal oxide vapor deposition layer is vapor-deposited is not limited, but is preferably 0.5 μm to 100 μm, more preferably 1 μm to 100 μm, even more preferably 5 μm to 100 μm, particularly preferably 10 μm to 50 μm, and most preferably 12 to 25 μm.
The metal oxide vapor-deposited layer surface of the resin film having the metal oxide vapor-deposited layer is preferably laminated and adhered to another layer via an oxygen-absorbing adhesive composition or a general-purpose adhesive layer.

Specific examples of metal oxides include metal oxides containing metal elements such as aluminum (Al), silicon (Si), magnesium (Mg), calcium (Ca), potassium (K), tin (Sn), sodium (Na), boron (B), titanium (Ti), lead (Pb), zirconium (Zr), yttrium (Y), zinc (Zn), vanadium (V), barium (Ba), and chromium (Cr).

The average composition of the metal oxide is expressed as _MOx (wherein, M represents a metal element, and the value of x varies depending on the metal element), such as _AlOx or _SiOx .
In the above _MOx , the upper limit of the range of x is the value when completely oxidized.
When x=0, it is a metal and is not transparent. Therefore, in the present invention, since _MOx is a metal oxide, the lower limit of the range of the value of x is a value greater than 0.
The upper limit of the value of x is 1.5 when M is aluminum, 2 when M is silicon, 1 when M is magnesium, 1 when M is calcium, 0.5 when M is potassium, 2 when M is tin, 0.5 when M is sodium, 1 when M is boron,
5 for titanium, 2 for lead, 1 for zirconium, 2 for yttrium, and 1.5 for yttrium.
Metal oxides represented by the average composition _MOx can have a value of x between these lower and upper limits.

In the present invention, the metal oxide vapor deposition layer preferably contains alumina (aluminum oxide) or silica (silicon oxide) among the above, and alumina is more preferred because it is capable of forming a transparent metal oxide vapor deposition layer and makes the oxygen-absorbing packaging container transparent, thereby enabling the contents inside the packaging to be visually confirmed.
Aluminum oxide with x ranging from 0.5 to 1.5 and silicon oxide with x ranging from 1.0 to 2.0 are more preferred.
The metal oxide vapor deposition layer may be composed of one or more metal oxides, or may be a mixture of two or more metal oxides. Furthermore, it may be composed of a single layer or multiple layers of the same or different compositions, and in the case of multiple layers, they do not have to be laminated adjacently.

[Method of forming a metal oxide vapor deposition layer]
The metal oxide deposition layer can be formed on a resin film using the above-mentioned metals or metal oxides as raw materials, for example, by utilizing a physical vapor deposition method (Physical Vapor Deposition method, PVD method) such as a vacuum deposition method, a sputtering method, an ion plating method, a cluster ion beam method, or a chemical vapor deposition method (Chemical Vapor Deposition method, CVD method) such as a plasma chemical vapor deposition method, a thermal chemical vapor deposition method, a photochemical vapor deposition method, or the like.

To explain more specifically, in the above-mentioned PVD method, for example, a winding-type deposition machine is used, and the resin film coming off the unwinding roll in a vacuum chamber is placed in a deposition chamber, where the deposition source heated in a crucible is evaporated, and further, if necessary, a metal oxide deposition layer is formed through a mask on the resin film on a cooled coating drum while blowing oxygen or the like from an oxygen outlet, and then the resin film with the metal oxide deposition layer formed thereon is wound up on a winding roll, thereby producing a resin film having a metal oxide deposition layer.

On the other hand, in the above-mentioned CVD method, a resin film on which a vapor deposition layer of silicon oxide is formed by plasma can be produced by introducing a mixed gas containing, for example, a monomer gas consisting of an organic silicon compound, oxygen gas, an inert gas, etc. from a vapor deposition raw material volatilization supply device onto the surface of a resin film unwound from a winding roll placed in a vapor deposition chamber, on the peripheral surface of a cooling electrode drum in the vapor deposition chamber.

In the above, the thickness of the metal oxide vapor deposition layer is preferably 30 Å to 3000 Å, more preferably 40 Å to 2500 Å, and even more preferably 50 Å to 2000 Å, in order to obtain sufficient oxygen barrier properties.
More specifically, in the above PVD method, the thickness of the metal oxide vapor deposition layer made of aluminum oxide is preferably 30 Å to 1000 Å, and more preferably about 50 Å to 500 Å.
In the above CVD method, the thickness of the metal oxide vapor deposition layer made of silicon oxide is preferably 30 Å to 3000 Å, and more preferably 100 Å to 300 Å.
If the thickness of the metal oxide vapor deposition layer is greater than the above range, there is a risk that the metal oxide vapor deposition layer is more susceptible to cracks, resulting in a decrease in oxygen barrier properties, and there are problems such as an increase in material costs, which is undesirable. Also, if the thickness is less than the above range, it is undesirable because it is easily difficult to achieve sufficient oxygen barrier properties.

When forming the above-mentioned metal oxide vapor deposition layer, the surface of the resin film to be vapor deposited can be cleaned by pretreatment using _SiOx plasma or the like, and polar groups, free radicals, etc. can be generated on the surface, thereby increasing the tight adhesion between the metal oxide vapor deposition layer and the resin film.
When two or more metal oxide deposition layers are successively laminated, it is preferable to use a plasma enhanced chemical vapor deposition apparatus having at least two deposition chambers.
By using such a plasma enhanced chemical vapor deposition apparatus, each metal oxide deposition layer can be deposited so as to have high gas barrier properties, and even higher gas barrier properties can be obtained than in the case of a single layer.
Furthermore, since deposition can be carried out continuously without exposure to the atmosphere, foreign matter, dust, etc. that may cause cracks can be prevented from being mixed between the metal oxide deposition layers, and the gas barrier properties are improved.
Furthermore, since two or more metal oxide vapor-deposited layers having different compositions can be laminated in succession, the permeation of oxygen gas, water vapor, etc. can be more efficiently suppressed.

<Oxygen-absorbing adhesive layer>
The oxygen-absorbing adhesive layer is a layer formed using an oxygen-absorbing adhesive composition, and is a layer that absorbs oxygen.

Oxygen-absorbing adhesive composition
The oxygen-absorbing adhesive composition of the present invention contains at least an oxygen-absorbing compound and an oxidation-promoting catalyst.
The oxygen absorbing compound contained may be one or more kinds, and the oxidation-promoting catalyst contained may be one or more kinds.
The oxygen-absorbing adhesive composition may further contain a modifier, a diluting solvent, various additives, and the like, as necessary.

The oxygen-absorbing adhesive composition may be prepared by adding an oxygen-absorbing compound to an existing adhesive composition, or the oxygen-absorbing adhesive composition may be prepared using an oxygen-absorbing compound as a resin component.
Here, the existing oxygen-absorbing adhesive composition may be a one-liquid oxygen-absorbing adhesive composition or a two-liquid oxygen-absorbing adhesive composition.
The oxygen absorbing adhesive composition and/or the above-mentioned existing adhesive composition may be curable or non-curable. If it is curable, it may be any of heat curable, photocurable, electron beam curable, etc.

The oxygen absorbing compound may or may not react with components contained in existing adhesive compositions, or may react with other oxygen absorbing compounds.
Depending on the presence or absence of the above reaction and the type of reaction, one or more oxygen-absorbing compounds can be selected and used from among those having no functional group, those having a (co)polymerizable functional group, and those having a functional group capable of reacting as a base agent or a curing agent.

Specifically, for example, an oxygen absorbing compound without a functional group and/or an oxygen absorbing compound with a functional group can be added to a two-liquid urethane adhesive composition containing an isocyanate compound and a hydroxyl group-containing compound. In this case, the functional group is preferably an isocyanate group and/or a hydroxyl group.

For example, the oxygen-absorbing adhesive composition can be prepared by combining the main component and curing agent with an isocyanate compound and an oxygen-absorbing compound having a hydroxyl group, with a hydroxyl group-containing compound and an oxygen-absorbing compound having an isocyanate group, or with an oxygen-absorbing compound having a hydroxyl group and an oxygen-absorbing compound having an isocyanate group.
The oxygen absorbing adhesive composition is preferably a urethane-based oxygen absorbing adhesive composition.

There are no particular limitations on the solid content of the oxygen-absorbing adhesive composition, but it is preferably 20% by mass or more and 100% by mass or less.

The content of the oxygen absorbing compound in the solids excluding the oxidation-promoting catalyst in the oxygen absorbing adhesive composition is preferably 40% by mass or more and 100% by mass or less. If it is less than the above range, there is a risk that the oxygen absorption will be insufficient. When it is 100% by mass, it means that the oxygen absorbing compound can be used as a resin component of the adhesive composition, and it has sufficient adhesiveness on its own, has a functional group that can be cured on its own, or is used in combination with an oxygen absorbing compound having a functional group that serves as a main agent and an oxygen absorbing compound having a functional group that serves as a curing agent.

The content of the oxidation-promoting catalyst in the oxygen-absorbing adhesive composition is preferably 10 ppm or more and 6000 ppm or less relative to the oxygen-absorbing compound.
If the content is less than the above range, the oxygen absorption may be insufficient, and if the content is more than the above range, the oxygen absorption is likely to become unstable, and the oxygen absorption may be consumed before the microwave-compatible oxygen-absorbing packaging container is produced, which may impair the effect of inhibiting deterioration due to oxygen after the microwave-compatible oxygen-absorbing packaging container is produced.

[Oxygen-absorbing compound]
The oxygen absorbing compound in the present invention has oxygen absorbing properties, generates little odor, and can be used alone or as a mixture with a resin or a resin composition.
The oxygen-absorbing compound of the present invention is an unsaturated five-membered ring-containing compound having one or more unsaturated five-membered rings, in which any bond between five carbon atoms constituting the unsaturated five-membered ring is a carbon-carbon double bond, and a monovalent and/or divalent or higher electron-donating organic group 1 is bonded to the unsaturated five-membered ring.

When there is one unsaturated five-membered ring, the five-membered ring or the organic group 1 has a functional group having active hydrogen, or a group in which the active hydrogen of the functional group having active hydrogen is substituted with a monovalent organic group 2, and when there are two or more unsaturated five-membered rings, the unsaturated five-membered rings are bonded to each other via a divalent or higher organic group 2 that substitutes the active hydrogen of the active hydrogen group on each of the organic groups 1.
When one molecule contains two or more such unsaturated five-membered rings, the unsaturated five-membered rings are bonded to each other via a structure in which an active hydrogen of a functional group having an active hydrogen on each of the five-membered rings or organic group 1 is substituted with a divalent or higher organic group 2.

The unsaturated five-membered ring, organic group 1, and organic group 2 present in one molecule may be one or more types, and the number may be one or more. The number of organic groups 1 bonded to one unsaturated five-membered ring may be one or more. Furthermore, the oxygen-absorbing compound may be a mixture of molecules having two or more structures in which the types and numbers of the unsaturated five-membered ring, organic group 1, and organic group 2 present in one molecule are different, as described above.

Organic group 1 donates electrons to the unsaturated five-membered ring, thereby increasing the electron density of the carbon-carbon double bond portion of the unsaturated five-membered ring, thereby increasing the reactivity with oxygen and improving the oxygen absorbency.
It is preferable that no electron-withdrawing group is bonded to the unsaturated five-membered ring, because the electron-withdrawing group bonded to the unsaturated five-membered ring reduces the electron density of the carbon-carbon double bond portion of the unsaturated five-membered ring, lowering the reactivity with oxygen and decreasing the oxygen absorption ability.
Specific molecular structures of the oxygen-absorbing compound include, for example, one unsaturated five-membered ring bonded to a monovalent or divalent organic group 1, one unsaturated five-membered ring bonded to a monovalent or divalent organic group 1 and a monovalent organic group 2 in that order, two unsaturated five-membered rings bonded via a divalent organic group 1 and a divalent organic group 2, and three unsaturated five-membered rings bonded via a divalent organic group 1 and a trivalent organic group 2.

In addition, the oxygen absorbing compound does not have to have a crosslinkable functional group, but can have one.
The crosslinkable functional group may be a functional group that was possessed by the compound from which the organic group 2 is derived, or may be a functional group that has been added by chemical modification.
Because the oxygen-absorbing compound has a crosslinkable functional group, when the oxygen-absorbing compound is mixed with a resin or a resin composition, the oxygen-absorbing compound has increased compatibility with the resin or the resin composition or becomes part of the crosslinked structure of the resin or the resin composition, making it less likely to bleed from the resin or the resin composition or the cured product of the resin composition, and the content of the oxygen-absorbing compound in the resin or the resin composition can be increased.

Specific examples of the crosslinkable functional group include an aliphatic hydroxyl group, an aromatic hydroxyl group, an isocyanate group, an amino group, an epoxy group, a (meth)acrylic group, etc. Among these, an isocyanate group and an aliphatic hydroxyl group are preferred.
In the case where the oxygen-absorbing compound has a crosslinkable functional group, the number of the crosslinkable functional group contained in one molecule is preferably 1 or 2 or more. In addition, the number of types of the crosslinkable functional group contained in one molecule may be 1 or 2 or more.
The functional group equivalent of the crosslinkable functional group is not particularly limited, but is preferably 500 to 20,000, more preferably 1,000 to 15,000, and even more preferably 1,500 to 10,000.

The number average molecular weight of the oxygen absorbing compound is preferably 100 to 10,000, more preferably 200 to 5,000, and even more preferably 300 to 2,500. If the number average molecular weight is smaller than the above range, it is likely to precipitate when mixed with a resin or resin composition. If the number average molecular weight is larger than the above range, it is likely to require the inclusion of a large amount of dilution solvent when mixed with a resin or resin composition because the viscosity of the mixture increases, making it difficult to obtain a thick film or layer and reducing suitability for coating.

The oxygen absorbing action of the oxygen absorbing compound of the present invention can be accelerated by heating or adding a catalyst.

(Unsaturated five-membered ring)
The unsaturated five-membered ring of the oxygen-absorbing compound has a carbon-carbon double bond within the unsaturated five-membered ring. Here, the carbon-carbon double bond is any bond between the five carbon atoms constituting the unsaturated five-membered ring, and there may be one or two carbon-carbon double bonds within one unsaturated five-membered ring.
The carbon-carbon double bond reacts with oxygen molecules in the air and captures the oxygen molecules, thereby allowing the oxygen absorbing compound to exhibit its oxygen absorbing properties.

Examples of compounds from which the above-mentioned unsaturated five-membered ring or the unsaturated five-membered ring to which the electron-donating organic group 1 is bonded include cyclopentadiene, dicyclopentadiene, norbornene, and derivatives thereof. The oxygen-absorbing compound can have an unsaturated five-membered ring derived from one or more of these selected from the group consisting of these.
The concentration of the unsaturated five-membered ring in the oxygen absorbing compound is not particularly limited, but is preferably 1 mass % or more and 70 mass % or less, and more preferably 5 mass % or more and 60 mass % or less. If the concentration is lower than the above range, the oxygen absorbing property is likely to be insufficient, it is difficult to obtain an oxygen absorbing compound having a property higher than the above range, and the balance between various physical properties is likely to be poor.

(Electron-donating organic group 1)
Specific examples of the organic group 1 include an alkyl group, an alkylene group, a cyclic alkylene group, etc. Among these, a cyclic alkylene group is preferable, and one which constitutes an aliphatic bicyclic alkylene group together with the unsaturated five-membered ring is more preferable.
Specific examples of the cyclic alkylene group include a cyclopropylene group, a cyclobutylene group, a cyclopentylene group, a cyclohexylene group, a cycloheptylene group, a cyclooctylene group, etc. Among these, a cyclopentylene group is more preferable.

(Electron-withdrawing organic group)
Specific examples of the electron-withdrawing group include a phenyl group, a phenylene group, a carbonyl group, and a halogen.
Indenes and coumarones in which only these electron-withdrawing groups are bonded to an unsaturated five-membered ring have a low electron density at the carbon-carbon double bond portion of the unsaturated five-membered ring, resulting in low reactivity with oxygen and low oxygen absorption.

(Functional group having active hydrogen)
A functional group having an active hydrogen is chemically reactive.
Specific examples of the functional group having an active hydrogen include a primary amino group, a secondary amino group, an aliphatic hydroxyl group, an aromatic hydroxyl group, an imino group, a carboxyl group, a urethane group, and a urea group. Among these, a primary amino group, a secondary amino group, an aliphatic hydroxyl group, and an aromatic hydroxyl group are preferred, and an aliphatic hydroxyl group is more preferred.

(Organic Group 2)
Organic group 2 is a monovalent and/or divalent or higher group which substitutes an active hydrogen of a functional group having an active hydrogen on the five-membered ring or organic group 1 and is bonded to the five-membered ring or organic group 1.
When there are two or more such unsaturated five-membered rings in one molecule, the unsaturated five-membered rings are bonded to each other via a structure in which the active hydrogen of a functional group having an active hydrogen is substituted with a divalent or higher organic group 2.
As a specific example, a functional group having an active hydrogen on organic group 1 reacts with an isocyanate group of an isocyanate compound having a structural portion from which organic group 2 is derived, and the active hydrogen is substituted for organic group 2, resulting in bonding via a urethane group.

By bonding organic group 2, the oxygen absorbing compound can have two or more of the unsaturated five-membered rings in one molecule, and furthermore, when mixed with a resin or a resin composition to prepare a mixture, the compatibility, dispersibility, and reactivity can be improved. Furthermore, the mixture or the cured product of the mixture can be adjusted to be soft.

The organic group 2 may be an aliphatic group, an aromatic group, or may have both an aliphatic group and an aromatic group.
The organic group 2 present in one molecule of the oxygen-absorbing compound may be of one type or of two or more types.
The organic group 2 is preferably a group containing a structural portion derived from an isocyanate compound and/or a hydroxyl group-containing compound. Here, the structural portion derived from an isocyanate compound and/or a hydroxyl group-containing compound includes a structural portion derived from a reaction product of an isocyanate compound and a hydroxyl group-containing compound.

(Isocyanate compounds)
Examples of isocyanate compounds from which the organic group 2 is derived include tetramethylene diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, norbornane diisocyanate, xylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, phenylene diisocyanate, diphenylether diisocyanate, hydrogenated diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, and their trimethylolpropane adducts, biuret forms, allophanate forms, isocyanurate forms (trimers), and various derivatives thereof. Among these, biuret forms of toluene diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate are preferred.

In the present invention, one or more types selected from the group consisting of these isocyanate-based compounds can be used as the origin of the structural portion of the monovalent and/or divalent or higher hydrocarbon group. When two or more types are used, two types may be used in the same molecule of the oxygen-absorbing compound, or molecules of the oxygen-absorbing compound having different types may be mixed.

The number average molecular weight of the isocyanate compound is preferably 100 to 10,000, more preferably 160 to 5,000. If the number average molecular weight is smaller than the above range, it is likely to precipitate when mixed with a resin or resin composition. If the number average molecular weight is larger than the above range, it is likely to require the inclusion of a large amount of dilution solvent when mixed with a resin or resin composition because the viscosity of the mixture increases, making it difficult to obtain a thick film or layer and reducing coating suitability.

(Hydroxyl Group-Containing Compound)
The hydroxyl group-containing compound is a compound from which the above organic group 2 is derived, and has two or more hydroxyl groups.
Examples of the hydroxyl group-containing compound include polyhydric alcohols, polyolefin polyols, polyether polyols, polyester polyols, polycarbonate polyols, poly(meth)acrylic acid ester polyols, phenoxy resins, and urethane chain-extended polyols thereof. Among these, polyether polyols and polyolefin polyols are preferred.
In order to prevent odor generation, the hydroxyl group-containing compound is preferably one that does not have a double bond in the aliphatic chain of the main skeleton or one that has two hydroxyl groups. Compounds that have a hydroxyl group at the terminal are preferred in that they are easily available, but it is not necessary to have a hydroxyl group at the terminal.

In the present invention, one or more of these selected from the group consisting of these can be used as the hydroxyl group-containing compound from which the organic group 2 is derived. When two or more types are used, two types may be used in the same molecule of the oxygen absorbing compound, or molecules of the oxygen absorbing compound having different types may be mixed.

The number average molecular weight of the hydroxyl group-containing compound is preferably 500 to 10,000, more preferably 750 to 5,000, and even more preferably 1,000 to 3,000. If the number average molecular weight is smaller than the above range, it is likely to precipitate when mixed with a resin or resin composition. If the number average molecular weight is larger than the above range, it is likely to require the inclusion of a large amount of dilution solvent when mixed with a resin or resin composition because the viscosity of the mixture increases, making it difficult to obtain a thick film or layer and reducing coating suitability.

Polyhydric alcohols Polyhydric alcohols are monomers having two or more hydroxyl groups.
Specific examples of polyhydric alcohols include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 1,6-hexanediol, cyclohexanedimethanol, 1,8-octanediol, 1,9-
Examples of the diols include nonanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol, 2,2,4-trimethyl-1,3-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,12-octadecanediol, and 2,2'-oxydiethanol; glycerin, mannitol, and sorbitol.
Among the above, ethylene glycol is preferred in terms of oxygen absorption.

Polyolefin polyol Polyolefin polyol is a polyolefin resin having two or more hydroxyl groups.
Specific examples of polyolefin polyols include those having a main skeleton that is a polyolefin, such as polyethylene, polypropylene, polybutylene, polybutadiene, hydrogenated polybutadiene, polyisoprene, hydrogenated polyisoprene, ethylene-vinyl acetate copolymer, ethylene-ethyl (meth)acrylate copolymer, ethylene-(meth)acrylic acid copolymer, or ethylene-propylene copolymer, and having a hydroxyl group.
Among these, ethylene-vinyl acetate copolymers and those having hydrogenated polyisoprene as the main skeleton are particularly preferred.

Polyether polyol Polyether polyol is a polyether resin having two or more hydroxyl groups.
Polyether polyols are obtained, for example, by dehydration condensation of the above-mentioned polyhydric alcohols or polyolefin polyols, and have a polyether structure in the main skeleton and a hydroxyl group.
Specific examples of polyether polyols include diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene ether diol, polypropylene ether diol, polybutylene ether diol, glycerin-modified polyether polyols, etc. Among these, polypropylene ether diol is particularly preferred.

Polyester Polyol Polyester polyol is a polyester resin having two or more hydroxyl groups.
The polyester polyols are obtained, for example, by esterification reaction between various polyvalent carboxylic acids or derivatives thereof and the above-mentioned polyhydric alcohols, polyolefin polyols, polyether polyols, etc., and have a polyester structure in the main skeleton and hydroxyl groups.

Specific examples of polycarboxylic acids include adipic acid, phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, succinic acid, oxalic acid, malonic acid, pimelic acid, azelaic acid, sebacic acid, suberic acid, glutaric acid, 1,4-cyclohexanedicarboxylic acid, and trimellitic acid. Derivatives of these polycarboxylic acids include esters, acid anhydrides, and acylation products.
Among the above, polyester polyols using two or more kinds of polyhydric alcohols and two or more kinds of polyvalent carboxylic acids in combination are preferred in order to reduce crystallinity.

Polycarbonate polyol Polycarbonate polyol is a polycarbonate resin having two or more hydroxyl groups.
Polycarbonate has a polyol-derived portion in the main skeleton, and this polyol-derived portion may be derived from the above-mentioned polyhydric alcohols, polyolefin polyol, polyether polyol, polyester polyol, or the like.
Among these, polycarbonate polyols using two or more kinds of polyhydric alcohols in combination are preferred in order to reduce crystallinity.

Poly(meth)acrylate polyol Poly(meth)acrylate polyol is a (meth)acrylate (co)polymer having two or more hydroxyl groups.
Poly(meth)acrylic acid ester polyol can be obtained, for example, by using a hydroxyl group-containing monomer such as 2-hydroxyethyl methacrylate or a (meth)acrylic acid ester having a hydroxyl group synthesized from one (meth)acrylic acid or a derivative thereof and one diol, and polymerizing the hydroxyl group-containing monomer with itself or copolymerizing it with a (meth)acrylic acid ester not having a hydroxyl group.
As the diol used in synthesizing the (meth)acrylic ester having a hydroxyl group, the above-mentioned diols, polyolefin polyols, polyether polyols, etc. can be used.
Among these, poly(meth)acrylic acid ester copolymers using 2-hydroxyethyl methacrylate are preferred.

Phenoxy resin is a resin obtained by reacting a polyhydric phenol compound with a polyhydric epoxy compound, and has a structure in which an aliphatic hydroxyl group is generated at the bond formed by the reaction of an aromatic hydroxyl group with an epoxy group.
As the phenoxy resin, those obtained by reacting a bisphenol with a diglycidyl etherified bisphenol are readily available and are common.
Examples of the polyhydric phenol compound include bisphenol A and bisphenol F, and examples of the polyhydric epoxy compound include bisphenol A diglycidyl ether and bisphenol F diglycidyl ether.
Among these, phenoxy resins using bisphenol A are preferred.
The terminal of the phenoxy resin may be an aromatic hydroxyl group or an epoxy group.

Urethane Chain-Extended Polyol The urethane chain-extended polyol is a polyol having two or more hydroxyl groups, obtained by extending the above-mentioned hydroxyl group-containing compound with a urethane chain.
The urethane chain-extended polyol can be obtained, for example, by polymerizing the above-mentioned various hydroxyl group-containing compounds with the above-mentioned isocyanate-based compounds to extend the urethane chain. If necessary, diamines or amino alcohols may be used in combination for polymerization.
Among the above, urethane chain-extended polyols obtained by reacting the above-mentioned various hydroxyl group-containing compounds having hydroxyl groups at both ends with a diisocyanate compound are preferred.

(Specific Examples of Oxygen Absorbing Compounds)
Specific examples of the oxygen-absorbing compound are given below.
3a,4,5,6,7,7a-hexahydro-4,7-methano-1H-indenol represented by formula (1), 3a,4,5,6,7,7a-hexahydro-4,7-methano-1H-indenamine represented by formula (1-b), and 3a,4,5,6,7,7a-hexahydro-4,7-methano-1H-inden-1-ol represented by formula (1-c) are examples of oxygen-absorbing compounds each having one unsaturated five-membered ring and one organic group 1, the organic group 1 having a hydroxyl group or an amino group as a functional group having active hydrogen.

（式中、ａは１以上の数であり、Ｒ¹は、炭素数１以上の有機基であり、少なくともアルキレンおよび／またはフェニレン構造を含み、さらに、多価アルコール類、ポリオレフィンポリオール、ポリエーテルポリオール、ポリエステルポリオール、ポリカーボネートポリオール、ポリ（メタ）アクリル酸エステルポリオール、フェノキシ樹脂、およびこれらのウレタン鎖伸長ポリオールからなる群から選ばれる１種または２種以上に由来する構造を含むことができる。） The oxygen-absorbing compound represented by formula (2) is an oxygen-absorbing compound that can be obtained, for example, by reacting a hydroxyl group, which is a functional group having an active hydrogen on organic group 1 of the oxygen-absorbing compound represented by formula (1), with an isocyanate group of R ¹ (NCO) _a , which is an isocyanate compound from which organic group 2 is derived, to substitute the active hydrogen of the hydroxyl group and bond a unsaturated five-membered rings and organic group 1 via R ¹ .

(In the formula, a is a number of 1 or more, ^R1 is an organic group having 1 or more carbon atoms, contains at least an alkylene and/or phenylene structure, and can further contain a structure derived from one or more selected from the group consisting of polyhydric alcohols, polyolefin polyols, polyether polyols, polyester polyols, polycarbonate polyols, poly(meth)acrylic acid ester polyols, phenoxy resins, and urethane chain-extended polyols thereof.)

（式中、ｆは０以上の数であり、Ｒ⁴とＲ⁵の各々は、炭素数１以上の有機基であり、少な
くともアルキレンおよび／またはフェニレン構造を含む有機基であり、さらに、多価アルコール類、ポリオレフィンポリオール、ポリエーテルポリオール、ポリエステルポリオール、ポリカーボネートポリオール、ポリ（メタ）アクリル酸エステルポリオール、フェノキシ樹脂、およびこれらのウレタン鎖伸長ポリオールからなる群から選ばれる１種または２種以上に由来する構造を含むことができる。） The oxygen-absorbing compound represented by formula (5) is an oxygen-absorbing compound represented by formula (2) in which a=2 and R ¹ is a group derived from, for example, an isocyanate compound OCN-R ⁴ -NCO or a hydroxyl group-containing compound HO-R ⁵ -OH, and containing a structural portion formed by the reaction of the two.

(In the formula, f is a number of 0 or more, and each of ^R4 and ^R5 is an organic group having one or more carbon atoms, which is an organic group containing at least an alkylene and/or phenylene structure, and which may further contain a structure derived from one or more selected from the group consisting of polyhydric alcohols, polyolefin polyols, polyether polyols, polyester polyols, polycarbonate polyols, poly(meth)acrylic acid ester polyols, phenoxy resins, and urethane chain-extended polyols thereof.)

（式中、ｂとｃの各々は１以上の数であり、Ｒ²は、炭素数１以上の有機基であり、少なくともアルキレンおよび／またはフェニレン構造を含み、さらに、多価アルコール類、ポリオレフィンポリオール、ポリエーテルポリオール、ポリエステルポリオール、ポリカーボネートポリオール、ポリ（メタ）アクリル酸エステルポリオール、フェノキシ樹脂、およびこれらのウレタン鎖伸長ポリオールからなる群から選ばれる１種または２種以上に由来する構造を含むことができる。） The oxygen-absorbing compound represented by formula (3) is an oxygen-absorbing compound represented by formula (2), for example, in which R ¹ is derived from an isocyanate compound and a hydroxyl group-containing compound, contains a structural part generated by the reaction of the two, and contains a hydroxyl group as a result of residual excess hydroxyl groups or chemical modification.

(In the formula, each of b and c is a number of 1 or more, ^R2 is an organic group having 1 or more carbon atoms, contains at least an alkylene and/or phenylene structure, and can further contain a structure derived from one or more selected from the group consisting of polyhydric alcohols, polyolefin polyols, polyether polyols, polyester polyols, polycarbonate polyols, poly(meth)acrylic acid ester polyols, phenoxy resins, and urethane chain-extended polyols thereof.)

（式中、ｄとｅの各々は１以上の数であり、Ｒ³は、炭素数１以上の有機基であり、少なくともアルキレンおよび／またはフェニレン構造を含み、さらに、多価アルコール類、ポリオレフィンポリオール、ポリエーテルポリオール、ポリエステルポリオール、ポリカーボネートポリオール、ポリ（メタ）アクリル酸エステルポリオール、フェノキシ樹脂、およびこれらのウレタン鎖伸長ポリオールからなる群から選ばれる１種または２種以上に由来する構造を含むことができる。） The oxygen-absorbing compound represented by formula (4) is an oxygen-absorbing compound in which, for example, R ¹ in formula (2) is derived from an isocyanate compound and a hydroxyl group-containing compound, contains a structural part generated by the reaction of the two, and contains an isocyanate group as a result of residual excess isocyanate group or chemical modification.

(In the formula, each of d and e is a number of 1 or more, ^R3 is an organic group having 1 or more carbon atoms, contains at least an alkylene and/or phenylene structure, and can further contain a structure derived from one or more selected from the group consisting of polyhydric alcohols, polyolefin polyols, polyether polyols, polyester polyols, polycarbonate polyols, poly(meth)acrylic acid ester polyols, phenoxy resins, and urethane chain-extended polyols thereof.)

[Prooxidation catalyst]
The oxidation-promoting catalyst is a compound that promotes the action of the oxygen-absorbing compound absorbing oxygen molecules and being oxidized.
Examples of the oxidation-promoting catalyst include peroxides and compounds containing cations of transition metals.
Specific examples of the peroxide include hydrogen peroxide.
The compound containing a cation made of a transition metal is preferably a metal soap made of a transition metal-containing compound capable of releasing a cation or complex of a transition metal atom and an anion or ligand made of a fatty acid.
As the transition metal, cobalt, manganese, iron, nickel, copper, etc. are preferred, and as the anion or ligand, anion or ligand formed of stearic acid, naphthenic acid, octylic acid, acetylacetonate, etc. are preferred.
The oxidation-promoting catalyst may be a metal soap formed by combining a cation made of one or more transition metals selected from the group consisting of the above transition metals with an anion made of one or more fatty acids selected from the group consisting of the above long-chain fatty acids. Specific compounds include cobalt octylate, cobalt acetylacetone (II), cobalt acetylacetone (III), manganese acetylacetone (III), and iron acetylacetone (III).

[Modifier]
The modifier is a compound having a functional group that reacts with the oxygen absorbing compound when the oxygen absorbing compound has a functional group, and various reactive monomers and resins can be used.
By including a modifier in the oxygen-absorbing adhesive composition, it is possible to bond the oxygen-absorbing compound to other components in the oxygen-absorbing adhesive composition, to adjust the content of the oxygen-absorbing compound in the oxygen-absorbing adhesive composition, and to adjust the hardness of the cured product of the oxygen-absorbing adhesive composition.

For example, when the oxygen absorbing compound has a hydroxyl group or an isocyanate group, a modifying agent made of an isocyanate compound and/or a hydroxyl group-containing compound can be used.
When the oxygen-absorbing adhesive composition is a urethane-based one, the equivalent ratio NCO/OH of the oxygen-absorbing adhesive composition is preferably 0.5 or more and 8 or less. If it is less than the above range, the curing of the oxygen-absorbing adhesive composition may be insufficient, and sufficient lamination strength (adhesive strength) may not be obtained, whereas if it is greater than the above range, the pot life of the oxygen-absorbing adhesive composition may be too short.

(Isocyanate-based compounds for use as modifiers)
The isocyanate compound for the modifier can be the isocyanate compound used in the synthesis of the oxygen absorbing compound, and any of aromatic isocyanates, aliphatic isocyanates, and urethane chain-extended isocyanates thereof can be used. In addition, in order for the oxygen absorbing adhesive composition to harden, it is preferable to use one having two or more isocyanate groups in one molecule. However, it is also possible to use an isocyanate compound having one isocyanate group in one molecule in the range that does not inhibit the sufficient effect of the oxygen absorbing adhesive composition.
As the isocyanate compound having two or more isocyanate groups in one molecule, a biuret form of hexamethylene diisocyanate is particularly preferred.

Specific examples of isocyanate compounds include tetramethylene diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, norbornane diisocyanate, xylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, phenylene diisocyanate, diphenylether diisocyanate, polymethylene polyphenyl polyisocyanate, and their trimethylolpropane adducts, biuret forms, allophanate forms, isocyanurate forms (trimers), and various derivatives thereof. Among these, the biuret forms of toluene diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate are preferred.

(Hydroxyl-containing compound for use as a modifier)
The hydroxyl group-containing compound for the modifier can be the hydroxyl group-containing compound used in the synthesis of the oxygen absorbing compound, and can be any of aromatic hydroxyl group-containing compounds, aliphatic hydroxyl group-containing compounds, and urethane chain-extended polyols thereof. In addition, in order for the oxygen absorbing adhesive composition to harden, it is preferable to have two or more hydroxyl groups in one molecule. However, it is also possible to use a hydroxyl group-containing compound having one hydroxyl group in one molecule in the range that does not inhibit the sufficient effect of the oxygen absorbing adhesive composition.
As the hydroxyl group-containing compound having two or more hydroxyl groups in one molecule, either an aromatic hydroxyl group-containing compound or an aliphatic hydroxyl group-containing compound can be used, and either an alcohol-based or a phenol-based compound can be used.
As the isocyanate compound having two or more isocyanate groups in one molecule, polyalkylene ether diols and urethane chain extended polyols of polyalkylene ether diols are particularly preferred.

[Dilution solvent]
The dilution solvent is not particularly limited as long as it uniformly dissolves or disperses the oxygen-absorbing compound and the oxidation-promoting catalyst, makes the oxygen-absorbing adhesive composition uniform, and is compatible with the dry lamination process. For example, an ester-based dilution solvent, a ketone-based dilution solvent, a hydrocarbon-based dilution solvent, etc. can be used.
Specific examples of ester-based diluent solvents include ethyl acetate, butyl acetate, etc., specific examples of ketone-based diluent solvents include methyl ethyl ketone, etc., and specific examples of hydrocarbon-based diluent solvents include toluene, etc. Among these, ethyl acetate is easy to use and is preferable.

[Various additives]
The oxygen-absorbing adhesive composition may contain various additives as necessary.
For example, curing accelerators, curing regulators for extending the pot life, antioxidants for suppressing a decrease in oxygen absorption during storage or use of the oxygen-absorbing adhesive composition and before the contents are placed in a package, adhesive assistants, tackifiers, leveling agents, ultraviolet absorbers, and defoamers may also be added.

(Cure Accelerator)
There are no particular limitations on the curing accelerator that can be used so long as it accelerates the curing reaction of the oxygen-absorbing adhesive composition.
Specific examples of the curing accelerator include metal-containing compounds such as dibutyltin dilaurate, dibutyltin diacetate, dioctyltin dilaurate, dibutyltin dimaleate, tetrabutyl titanate, and tetraisopropyl titanate, and tertiary amines such as 1,8-diaza-bicyclo(5,4,0)undecene-7, 1,5-diazabicyclo(4,3,0)nonene-5, and triethanolamine. One or more types selected from the group consisting of these can be used.

(Cure adjuster)
When the pot life of the oxygen-absorbing adhesive composition is shortened due to the oxidation-promoting catalyst contained therein, the pot life can be extended by using a cure regulator in combination.
Specific examples of the hardening regulator include phosphoric acids, such as orthophosphoric acid, metaphosphoric acid, polyphosphoric acid, and ester derivatives thereof. One or more types selected from the group consisting of these can be used.
The amount of reaction regulator added is preferably 200 ppm or more and 400 ppm or less relative to the resin component of the oxygen-absorbing adhesive composition. If the amount is less than this range, it is difficult to obtain the effect of extending the pot life, and if the amount is more than this range, there is a risk that the curing of the oxygen-absorbing adhesive composition is inhibited.

(Antioxidant)
The oxygen-absorbing adhesive composition may contain an antioxidant in order to suppress deterioration of oxygen absorption properties during storage or use of the oxygen-absorbing adhesive composition, and even in processes before a package made using the oxygen-absorbing adhesive composition contains contents, and to maintain high oxygen absorption properties after the contents are contained.
Specific examples of the antioxidant include phenols, lactones, thioethers, gallic acid, ascorbic acid, erythorbic acid, catechin, dibutylhydroxytoluene, tocopherol, citric acid, butylhydroxyanisole, phosphite, hindered amine, and aromatic amines. One or more types selected from the group consisting of these can be used.

In addition, when it is assumed that heat or light is used as a trigger for expressing oxygen absorbing ability, it is preferable to use an antioxidant having low heat resistance and light resistance, such as ascorbic acid or tocopherol, and it is not preferable to use an antioxidant having high heat resistance and light resistance, such as a phenol-based antioxidant.
The amount of the antioxidant added is preferably 10 ppm or more and 10,000 ppm or less relative to the oxygen absorbing compound. If the amount is less than the above range, the antioxidant effect is likely to be insufficient, and if the amount is more than the above range, there is a risk that the oxygen absorbing property will decrease.

(Adhesive assistant)
As an adhesion aid for aiding adhesive strength, a silane coupling agent is preferred.
Examples of the silane coupling agent include γ-glycidoxypropyltrialkoxysilane, γ-methacryloxypropyltrialkoxysilane, γ-glycidoxypropylmethyldialkoxysilane, β-(3,4-epoxycyclohexyl)ethyltrialkoxysilane, γ-aminopropyltrialkoxysilane, γ-aminopropylmethyldialkoxysilane, N-(β-aminoethyl)-γ-aminopropyltrialkoxysilane, N-(β-aminoethyl)-γ-aminopropylmethyldialkoxysilane, N-butyl-3-amino-2-methylpropyltrialkoxysilane, γ-mercaptopropyltrialkoxysilane, and γ-mercaptopropylmethyldialkoxysilane. The alkoxy group is preferably a methoxy group or an ethoxy group, and one or more selected from the group consisting of these can be used.

(Tackifier)
Examples of the tackifier include paraffin wax, polyethylene wax, rosin, rosin glycerin ester, terpene, and alkylphenol. One or more types selected from the group consisting of these can be used.

(Leveling Agent)
The leveling agent may be an acrylic polymer-based agent, a modified silicone-based agent, an acetylene diol-based agent, or the like. One or more types selected from the group consisting of these may be used.

(Ultraviolet absorber)
Examples of the ultraviolet absorbing agent include benzotriazole-based, hydroxyphenyltriazine-based, and hindered amine-based agents, and one or more types selected from the group consisting of these may be used.

(Antifoaming agent)
The antifoaming agent may be a surfactant, a polyether-modified silicone oil, or the like. One or more kinds selected from the group consisting of these may be used.

<<Method for preparing oxygen-absorbing adhesive composition>>
The oxygen-absorbing adhesive composition can be produced by mixing all of the components, such as the oxygen-absorbing compound, the oxidation-promoting catalyst, and, if necessary, the modifier, the diluting solvent, various additives, etc. Alternatively, the oxygen-absorbing adhesive composition can be produced by mixing the oxygen-absorbing compound, the oxidation-promoting catalyst, and, if necessary, the modifier, the diluting solvent, various additives, etc., with an existing adhesive composition.
The method for carrying out the above mixing and the order in which the components are mixed are not particularly limited, and the method and mixing order used in preparing a general adhesive composition can be applied.
Specific mixing methods include a method of dissolving in a solvent and mixing, and a melt-kneading method. In this case, it is preferable to adjust the heating temperature in order to increase the solubility and dispersibility.

<<Method of using the oxygen-absorbing adhesive composition>>
There are no particular limitations on the method of using the oxygen-absorbing adhesive composition, and any method for using it as an adhesive can be used.
For example, there may be mentioned a non-solvent type lamination method in which the coating is heated to obtain an appropriate viscosity, and a dry lamination method in which a dilution solvent or other compounded adhesive is added to adjust the coating viscosity to an appropriate level.
When forming an oxygen-absorbing adhesive layer using the oxygen-absorbing adhesive composition, the coating amount is preferably 2 to 5 g/m ² , and more preferably 3 to 5 g/m ^2. If the coating amount is less than the above range, there is a risk that sufficient oxygen absorption cannot be obtained, and if the coating amount is more than the above range, the oxygen absorption does not change significantly, which leads to cost disadvantages, and is therefore not preferred.

The oxygen-absorbing packaging material for retort packaging containers obtained by forming and bonding an oxygen-absorbing adhesive layer using the oxygen-absorbing adhesive composition is preferably aged at 20°C or higher and 50°C or lower for 2 days or higher and 5 days or lower.
In addition, when aging, in order not to decrease the oxygen absorbing property of the oxygen absorbing packaging material for a microwave oven compatible packaging container, it is preferable to carry out the aging at as low a temperature as possible or in an inert gas atmosphere.
When storing the oxygen-absorbing packaging material for microwave-compatible packaging containers thus produced, it is preferable to store it at 10°C or below or in an inert gas atmosphere in order to prevent a decrease in the oxygen absorption properties of the oxygen-absorbing packaging material for microwave-compatible packaging containers.

About objects that can be glued
There are no particular limitations on the objects to which the oxygen absorbing adhesive composition can be adhered, and for example, it is possible to adhere to resin molded products, resin films, paper, inorganic vapor deposition film surfaces, and inorganic oxide vapor deposition film surfaces.

Specific examples of resins for resin films to which the oxygen-absorbing adhesive composition can be adhered include polyester resins such as polyethylene terephthalate (PET), polyamide resins such as various nylons, polyethylene resins, polypropylene resins, cyclic polyolefin resins, polystyrene resins, acrylonitrile-styrene copolymers (AS resins), acrylonitrile-butadiene-styrene copolymers (ABS resins), polyolefin resins such as polybutene resins, polyvinyl chloride resins, polycarbonate resins, polyimide resins, polyamideimide resins, diallyl phthalate resins, silicone resins, polysulfone resins, polyphenylene sulfide resins, polyethersulfone resins, polyurethane resins, cellulose resins, poly(meth)acrylic resins, polyvinylidene chloride resins, acetal resins, and fluorine-based resins.

Specific examples of papers to which the oxygen-absorbing adhesive composition can be bonded include, for example, strong sizing bleached or unbleached paper base materials for paper layers, or paper base materials such as pure white roll paper, kraft paper, paperboard, coated paper, processed paper, milk base paper, and the like.
Specific examples of inorganic oxides of the inorganic vapor deposition layer to which the oxygen-absorbing adhesive composition can be adhered include silica, alumina, indium tin oxide, zinc oxide, tin oxide, titanium oxide, zirconium oxide, vanadium oxide, barium oxide, chromium oxide, silicon nitride, silicon carbide, etc. Among these, silica and alumina are preferred.

<Antioxidant shielding resin layer>
The antioxidant-shielding resin layer is a resin layer for suppressing the migration of various additives, particularly antioxidants, from the sealant layer to the oxygen-absorbing adhesive layer.
The migration of various additives contained in the sealant layer, particularly the antioxidant, into the oxygen-absorbing adhesive layer is inhibited by the antioxidant-shielding resin layer present in between, thereby inhibiting a decrease in the oxygen absorption efficiency of the oxygen-absorbing adhesive layer.
The antioxidant-shielding resin layer may be composed of one layer or two or more layers. In the case of two or more layers, the two or more layers may have the same or different compositions and thicknesses and may be laminated by any lamination means.
The thickness of the antioxidant-shielding resin layer is preferably 5 μm to 100 μm, more preferably 10 μm to 50 μm, and even more preferably 12 to 25 μm, for the purposes of providing an antioxidant-shielding effect and appropriate strength and stiffness to the packaging material.
If the thickness is thinner than the above range, there is a risk that the antioxidant shielding effect, strength, and stiffness will be insufficient, and if the thickness is thicker than the above range, there will be no significant change in the antioxidant shielding effect, but the stiffness will be too high and it may become difficult to handle.

The resin contained in the antioxidant-shielding resin layer is not particularly limited as long as it can suppress the migration of various additives, particularly the antioxidant, and any commonly known and commonly used resin can be used.
There are no particular limitations on the resin contained in the antioxidant-shielding resin layer, so long as it can suppress the migration of various additives, particularly the antioxidant.

Specific examples of the resin for the antioxidant-shielding resin layer include polyester-based resins such as polyethylene terephthalate (PET) and polyethylene naphthalate, polyamide-based resins such as nylon, and polyolefin-based resins such as polypropylene.
Among the above, polyester-based resins and polyamide-based resins are preferred due to their excellent flexibility, puncture resistance, pinhole resistance, and the like, and polyamide-based resins are more preferred.
The film made of the above resin may be either an unstretched film or a uniaxially or biaxially stretched film.
Among the above, a biaxially oriented PET film and a biaxially oriented polyamide film are preferably used, and a biaxially oriented polyamide film is more preferably used.

If necessary, plastic compounding agents and additives such as lubricants, crosslinking agents, antioxidants, ultraviolet absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, and pigments can be added to the resin film used in the antioxidant-shielding resin layer for the purpose of improving or modifying processability, heat resistance, weather resistance, mechanical properties, dimensional stability, antioxidant properties, slipperiness, releasability, flame retardancy, mildew resistance, electrical properties, strength, etc. The amount of addition is within a range that does not adversely affect other performances, depending on the purpose.
It can be added optionally.

The antioxidant-shielding resin layer may be formed by laminating a pre-prepared resin film for the antioxidant-shielding resin layer by adhesion via an adhesive or the like, or may be formed and laminated by melt-extruding a molten resin composition onto another layer.
The resin film for the antioxidant-shielding resin layer may be prepared by melt-extruding one or more resin compositions and forming a film by an inflation method, or by extrusion using a T-die molding or the like to melt-extrude onto a roll and narrow the film to form a resin film. Here, it is preferable to subject one or both sides of the prepared resin film to a corona treatment before bonding and laminating.
When forming the antioxidant-shielding resin layer by melt extrusion, the resin composition is melted, (co)extruded, and poured onto the layer to be laminated, and the antioxidant-shielding resin layer can be formed by an extrusion method using a T-die molding using a feed block method or a multi-manifold method.
In either method, a single antioxidant-shielding resin layer or multiple antioxidant-shielding resin layers using resin compositions of the same or different compositions can be prepared.

The antioxidant-shielding resin layer can be laminated to other layers via an adhesive layer or an oxygen-absorbing adhesive layer. Furthermore, if necessary, in order to strengthen the adhesive strength between the antioxidant-shielding resin layer and the adhesive layer or the oxygen-absorbing adhesive layer, the surface of the antioxidant-shielding resin layer that comes into contact with the adhesive layer or the oxygen-absorbing adhesive layer can be subjected in advance to a physical surface treatment such as corona discharge treatment, ozone treatment, plasma treatment, glow discharge treatment, sandblasting treatment, etc., or a chemical surface treatment such as an oxidation treatment using chemicals.

<Sealant layer>
The heat seal layer in the present invention preferably has a good balance of softening point, heat resistance, resistance to oxidation and deterioration, etc., so as to withstand high temperatures during microwave oven treatment and to exhibit excellent heat sealability.
For this reason, the sealant layer preferably contains a highly heat-resistant heat-sealable resin and an antioxidant.
As the highly heat-resistant heat-sealable resin, polyolefin-based resins are preferred, and polypropylene-based resins are more preferred, in view of the balance between heat-sealability, heat resistance, and resistance to oxidative deterioration.
The softening point of the sealant layer is preferably 120°C or higher and 170°C or lower, more preferably 125°C or higher and 165°C or lower, and even more preferably 130°C or higher and 160°C or lower.
The softening point of the sealant layer does not necessarily coincide with that of the highly heat-resistant heat-sealable resin, but varies depending on the types and contents of the resin, antioxidant, other additives, etc., contained at the same time.
When the softening point of the sealant layer is within the above range, it is easy to obtain an excellent balance between heat sealability, heat resistance, and resistance to oxidative deterioration.
The antioxidant can suppress oxidative deterioration of the resin in the sealant layer by eliminating radicals that occur over time or when heated to form the sealant layer or a resin film for the sealant layer.

Polypropylene-based resins have higher resistance to oxidation and deterioration than polyethylene-based resins, but when used as is, the resistance to oxidation and deterioration of the sealant layer is likely to be insufficient. However, by simultaneously incorporating an antioxidant, the resistance to oxidation and deterioration of the sealant layer is improved, and it is possible to achieve an excellent balance of softening point, heat resistance, resistance to oxidation and deterioration, etc.

The content of the antioxidant in the sealant layer is preferably 100 ppm or more and 10,000 ppm or less, more preferably 500 ppm or more and 7,000 ppm or less, and even more preferably 1,000 ppm or more and 5,000 ppm or less. If it is less than the above range, the antioxidant effect is likely to be insufficient. Also, if it is more than the above range, the improvement of the antioxidant effect will reach a plateau, and the antioxidant will easily reach the oxygen absorbing adhesive layer, which may hinder the oxygen absorbing property.

The sealant layer may also contain other heat-sealable resins within the range that does not impair the excellent balance of properties such as softening point, heat resistance, and resistance to oxidative deterioration.
The sealant layer may be composed of a single layer, or may be composed of two or more layers having the same or different compositions and thicknesses.
The thickness of the sealant layer is preferably from 10 μm to 200 μm, and more preferably from 30 μm to 100 μm.

The sealant layer may contain any additive other than the antioxidant, provided that the additive does not significantly impair the effects of the present invention. Examples of the additive include various resin additives that are generally used to adjust the moldability, productivity, and various physical properties of the resin film, such as antiblocking agents, slip agents, pigments, flow control agents, flame retardants, fillers, ultraviolet absorbers, and surfactants.
Furthermore, it is particularly preferable to form the sealant layer from a CPP film (biaxially oriented polypropylene film) produced using a resin composition containing a microwave-safe polypropylene-based resin and an antioxidant.

[Heat sealable resin]
Generally, the heat-sealable resin may be a polyolefin resin, a polyvinyl acetate resin, a poly(meth)acrylic resin, a polyvinyl chloride resin, etc. These resins may be used alone or in combination.

(Polyolefin resin)
Examples of polyolefin-based resins include polyolefins obtained by polymerizing olefin-based monomers, and modified polyolefin-based resins obtained by graft polymerization, block polymerization, random polymerization, or the like, or by copolymerization, using an olefin-based monomer in combination with various polymerizable monomers.
Polyolefin resins are classified into, for example, polyethylene resins and polypropylene resins depending on the skeleton of the monomer used in the synthesis of the polyolefin, and may be copolymers. In the present invention, the term "polyethylene resin" is added as a general term for various types, and for example, polyethylene resin is also used as a general term for various types of polyethylene.
Polyolefins produced by polymerizing α-olefins such as ethylene, propene, 1-butene, 1,3-butadiene, and 1-hexene as raw materials are called polyethylene-based resins, polypropylene-based resins, polybutylene-based resins, polybutadiene-based resins, polyhexene-based resins, and the like, respectively.
Resins modified using unsaturated carboxylic acids or their anhydrides, such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, and itaconic acid, are also called acid-modified polyolefin resins.

Specific examples of polyolefin resins include polyethylene, low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, ethylene-α-olefin copolymers polymerized using a metallocene catalyst, polypropylene resins, ethylene-vinyl acetate copolymers, ethylene-vinyl alcohol copolymers, ionomer resins, ethylene-acrylic acid copolymers, ethylene-ethyl acrylate copolymers, ethylene-methacrylic acid copolymers, ethylene-methyl methacrylate copolymers, ethylene-propylene copolymers, methylpentene (co)polymers, butene (co)polymers, polyisoprene, ethylene-acrylic acid copolymers, ethylene-methacrylic acid copolymers, and cyclic olefin (co)polymers such as polynorbornene. The copolymer may be any of graft polymers, block polymers, random polymers, and the like.

Generally, polymerization methods include high-pressure methods for low-density polyethylene, low-pressure polymerization methods (gas-phase polymerization using a Ziegler-Natta catalyst or liquid-phase polymerization using a metallocene catalyst) for linear low-density polyethylene, slurry methods, solution methods, and gas-phase polymerization methods.

[Antioxidant]
Examples of the antioxidant contained in the sealant layer include phenol-based, hindered phenol-based, lactone-based, thioether-based, gallic acid-based, ascorbic acid, erythorbic acid, catechin, dibutylhydroxytoluene, tocopherol, citric acid, butylhydroxyanisole, phosphite, hindered amine, and aromatic amine-based antioxidants. One or more types selected from the group consisting of these antioxidants may be used.

<Method of forming sealant layer>
The method for forming the sealant layer is not particularly limited, and any conventionally known method for laminating a sealant layer can be used.
For example, a sealant film consisting of one or more layers for the sealant layer may be prepared in advance, and the sealant film may be laminated by adhering it to other layers constituting the packaging material via an adhesive, etc. The method for preparing the sealant film may involve melt-extruding one or more resin compositions and forming them into a film by an inflation method, or melt-extruding onto a roll and constricting it by an extrusion method using a T-die molding or the like to form a film.
Here, it is preferable that one side of the prepared sealant film is corona-treated, and the corona-treated side is placed opposite the side to be laminated, and then laminated by adhesion.

Alternatively, the resin composition for forming the sealant layer may be melted, melt (co)extruded, and poured onto the layers to be laminated, and a sealant layer consisting of one or more layers may be laminated onto other layers constituting the packaging material by an extrusion method using a T-die molding method using a feed block method or a multi-manifold method, to form a sealant layer.
In either method, multiple sealant layers can be produced by co-melt extrusion using resin compositions of the same or different compositions.

<Adhesive layer>
The adhesive layer may be, for example, any of a layer (extruded resin layer) formed by a (co)extrusion lamination method or a T-die (co)extrusion method in which an adhesive resin composition is melt-extruded, a layer (coated layer) formed by applying a liquid adhesive resin composition, and a layer (dry laminate layer) formed by dry lamination using a dry laminate adhesive.

Examples of resins that can be used in the adhesive resin composition include polyolefin resins, acid-modified polyolefin resins obtained by acid-modifying polyolefin resins by graft polymerization or copolymerization with unsaturated carboxylic acids or their anhydrides, such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, etc., polyvinyl acetate resins, poly(meth)acrylic resins, polyvinyl chloride resins, and other resins. These resins can be used alone or in combination of two or more.

Examples of polyolefin-based resins include polyolefins obtained by polymerizing olefin-based monomers, and modified polyolefin-based resins obtained by graft polymerization, block polymerization, random polymerization, or the like, or by copolymerization, using an olefin-based monomer in combination with various polymerizable monomers.
Polyolefin resins are classified into, for example, polyethylene resins and polypropylene resins depending on the skeleton of the monomer used in the synthesis of the polyolefin, and may be copolymers. In the present invention, the term "polyethylene resin" is added as a general term for various types, and for example, polyethylene resin is also used as a general term for various types of polyethylene.
Polyolefins produced by polymerizing α-olefins such as ethylene, propene, 1-butene, 1,3-butadiene, and 1-hexene as raw materials are called polyethylene-based resins, polypropylene-based resins, polybutylene-based resins, polybutadiene-based resins, polyhexene-based resins, and the like, respectively.
Resins modified using unsaturated carboxylic acids or their anhydrides, such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, and itaconic acid, are also called acid-modified polyolefin resins.

Specific examples of polyolefin resins used in the adhesive layer include polyethylene, low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, ethylene-α-olefin copolymers polymerized using a metallocene catalyst, polypropylene resins, ethylene-vinyl acetate copolymers, ethylene-vinyl alcohol copolymers, ionomer resins, ethylene-acrylic acid copolymers, ethylene-ethyl acrylate copolymers, ethylene-methacrylic acid copolymers, ethylene-methyl methacrylate copolymers, ethylene-propylene copolymers, methylpentene (co)polymers, butene (co)polymers, polyisoprene, ethylene-acrylic acid copolymers, ethylene-methacrylic acid copolymers, and cyclic olefin (co)polymers such as polynorbornene. The copolymers may be any of graft polymers, block polymers, random polymers, etc.

The adhesive layer may contain additives such as antioxidants, ultraviolet absorbers, light stabilizers, antistatic agents, antiblocking agents, flame retardants, crosslinking agents, and colorants, provided the additives do not impair the properties of the present invention.
The thickness of the adhesive layer is not particularly limited, but is preferably 1 g/ ^m2 or more and 20 g/ ^m2 or less, or 1 μm or more and 20 μm or less. By setting the thickness of the extruded resin layer within the above numerical range, stable adhesive strength can be obtained.
In addition, examples of adhesives that can be used for dry lamination that constitute the adhesive layer formed by dry lamination include two-component curing urethane adhesives, polyester urethane adhesives, polyether urethane adhesives, acrylic adhesives, polyester adhesives, polyamide adhesives, polyvinyl acetate adhesives, epoxy adhesives, rubber adhesives, and others.

<Anchor coat layer>
The anchor coat layer is a layer formed by applying and drying an anchor coat agent, and can improve the adhesion between adjacent layers.
The anchor coating agent may be any resin having a heat resistant temperature of 135° C. or higher, such as a vinyl modified resin, an epoxy resin, a urethane resin, a polyester resin, or a polyethyleneimine.
Among the above, a curable anchor coating agent is particularly preferred which contains a polyacrylic or polymethacrylic resin (polyol) having two or more hydroxyl groups in one molecule as a base agent and an isocyanate compound as a curing agent.
A silane coupling agent may also be used in combination, and nitrocellulose may also be used in combination to improve heat resistance. The thickness of the anchor coat layer is not particularly limited, but is preferably, for example, 0.05 μm or more and 1 μm or less.

<Functional Layer>
Examples of the functional layer include an auxiliary barrier layer, a fragrance retaining layer, a light blocking layer, and a reinforcing layer.

[Auxiliary Barrier Layer]
The auxiliary barrier layer is a layer made of a resin having a barrier property against oxygen gas, water vapor, and the like.
Specific examples of the resin that can be used include polyacrylic resins, polymethacrylic resins, polyacrylonitrile resins, polymethacrylonitrile resins, polystyrene resins, polycarbonate resins, polyethylene terephthalate resins, or resins in which a part of the ethylene component and/or terephthalate component is copolymerized or modified with another di- or higher polyhydric alcohol component or dicarboxylic acid component, or polyester resins such as polyethylene naphthalate resins, polyamide resins, saponified ethylene-vinyl acetate copolymers, polyvinyl alcohol resins, polyvinyl chloride resins, polyvinylidene chloride resins, and other resins.

Among the above resins, it is preferable to use a resin that has both aroma retention and barrier properties against oxygen gas or water vapor. Specifically, it is preferable to use a resin with excellent aroma retention and barrier properties, such as saponified ethylene-vinyl acetate copolymer, polyamide resin, polyacrylonitrile resin, or polyester resin.

[Fragrance-retaining layer]
The aroma retaining layer is a layer that has excellent aroma retaining properties, such as little absorption of flavoring ingredients contained in the contents to be filled and packaged, and further has properties such as not causing any strange taste or unpleasant odor.

[Light-shielding layer]
The light-shielding layer is made of a light-shielding material and prevents ultraviolet light and/or visible light from reaching the contents and causing deterioration of the contents due to light.
The light-shielding layer can be formed using a white ink mainly composed of titanium oxide or the like, a black ink mainly composed of carbon black or the like, a gray ink mainly composed of aluminum paste, or a colorant-colored resin film made light-shielding by adding a pigment or dye or the like.
These light-shielding materials can be used alone or in combination of two or more.
When white ink, black ink or gray ink is used, the thickness of the light-shielding layer is preferably 4 μm or more and 12 μm or less, and more preferably 5 μm or more and 9 μm or less.

[Reinforcement layer]
The reinforcing layer is a layer that imparts mechanical strength, deformation resistance, pinhole resistance, heat resistance, sealability, quality maintenance, workability, sanitation, and the like to the packaging material.
The reinforcing layer may be formed from any of an extrusion-formed or inflation-formed resin film, a resin coating film, synthetic paper, and the like.

Specific examples of the resin contained in the reinforcing layer include low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid or methacrylic acid copolymer, methylpentene polymer, polybutene resin, polyvinyl chloride resin, polyvinyl acetate resin, polyvinylidene chloride resin, vinyl chloride-vinylidene chloride copolymer, poly(meth)acrylic resin, polyacrylonitrile resin, polystyrene resin, acrylonitrile-styrene copolymer (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), polyester resin, polyamide resin, polycarbonate resin, polyvinyl alcohol resin, saponified ethylene-vinyl acetate copolymer, fluorine resin, diene resin, polyacetal resin, polyurethane resin, cellulose, nitrocellulose, and other known resins can be used.
The above resin film may be either unstretched or uniaxially or biaxially stretched.
The thickness of the reinforcing layer is not particularly limited, but may be selected from the range of several μm to about 300 μm.

[Sol-gel coating layer]
The sol-gel coating layer is a layer provided adjacent to the metal oxide vapor deposition layer, and can improve the gas barrier properties against oxygen gas, water vapor, and the like.
The sol-gel coating layer is a layer formed from a resin composition containing a metal alkoxide, a water-soluble polymer, a sol-gel catalyst, water, an organic solvent, and the like.
The resin composition contains a hydrolysate and/or a hydrolysis condensate of a metal alkoxide produced by a sol-gel method, and the sol-gel coating layer contains a product resulting from further polycondensation by the sol-gel method.

The sol-gel coating layer may be a composite polymer layer consisting of one layer or two or more layers. The thickness of the sol-gel coating layer after drying is preferably in the range of 0.01 to 100 μm, and more preferably 0.1 to 50 μm. If the thickness after drying is less than 0.01 μm, the effect of improving the gas barrier properties may be insufficient, and if it is more than 100 μm, cracks may easily occur in the sol-gel coating layer.

(Metal alkoxide)
As the metal alkoxide, one or more compounds represented by the following general formula can be preferably used.
^R1nM ( _OR2 ⁾ _m
(In the formula, R ¹ and R ² represent an organic group having 1 to 8 carbon atoms, M represents a metal atom, n represents an integer of 0 or more, m represents an integer of 1 or more, and n+m represents the atomic valence of M.)
Here, the metal atom M may be silicon, zirconium, titanium, aluminum, or the like.
R ¹ and R ² may be the same or different. In addition, in the same molecule, multiple R ^2s may be the same or different.
Specific examples of R ¹ and R ² include alkyl groups selected from the group consisting of methyl, ethyl, n-propyl, i-propyl, n-butyl and i-butyl groups.

Examples of such metal alkoxides include tetramethoxysilane Si( _OCH3 ) ₄ , tetraethoxysilane Si( _OC2H5 ) ₄ , tetrapropoxysilane Si( _OC3H7 ) ₄ , _{tetrabutoxysilane} Si( _OC4H9 ) _{4 ,} and silane coupling agents having functional groups that bond with organic substances. These may be used _alone or in combination of two or more.
As the silane coupling agent, known organoalkoxysilanes containing an organic reactive group can be used, and one or more of them can be used in combination.
In particular, organoalkoxysilanes having an epoxy group are suitable, and for example, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, or the like can be used.

In the present invention, the silane coupling agent as described above can be contained in an amount of about 1 to 20 parts by mass per 100 parts by mass of the total amount of metal alkoxide.

(Water-soluble polymer)
As the water-soluble polymer, polyvinyl alcohol resin, ethylene-vinyl alcohol copolymer, etc. are preferable.
Examples of commercially available ethylene-vinyl alcohol copolymers include EVAL EP-F101 (ethylene content: 32 mol %) manufactured by Kuraray Co., Ltd., and Soarnol D2908 (ethylene content: 29 mol %) manufactured by Nippon Synthetic Chemical Industry Co., Ltd.

In addition, examples of commercially available polyvinyl alcohol-based resins include RS polymer RS-110 (saponification degree = 99%, polymerization degree = 1,000) manufactured by Kuraray Co., Ltd., Kuraray Poval LM-20SO (saponification degree = 40%, polymerization degree = 2,000) manufactured by the same company, and Gohsenol NM-14 (saponification degree = 99%, polymerization degree = 1,400) manufactured by Nippon Synthetic Chemical Industry Co., Ltd.
The content of the water-soluble polymer is preferably 5 to 500 parts by mass relative to 100 parts by mass of the metal alkoxide. If it is less than 5 parts by mass, the film formability of the sol-gel coating layer tends to be poor and the brittleness tends to increase, and the weather resistance tends to decrease, while if it exceeds 500 parts by mass, the effect of improving the gas barrier property tends to decrease.

(Sol-gel catalyst)
As the sol-gel catalyst, an amine compound or an acid is preferable.
As the amine compound, a tertiary amine that is substantially insoluble in water and soluble in an organic solvent is preferable. Specifically, for example, N,N-dimethylbenzylamine, tripropylamine, tributylamine, tripentylamine, etc. can be used. In particular, N,N-dimethylbenzylamine is preferable.
The content of the amine compound is preferably, for example, 0.01 to 1.0 part by mass, particularly 0.03 to 0.3 part by mass, per 100 parts by mass of the metal alkoxide. If the content is less than 0.01 part by mass, the catalytic effect is too small, whereas if the content is more than 1.0 part by mass, the catalytic effect is too strong, causing the reaction rate to become too fast and tending to become non-uniform.
As the acid, for example, mineral acids such as sulfuric acid, hydrochloric acid, nitric acid, etc., and organic acids such as acetic acid, tartaric acid, etc. can be used.
The content of the acid is preferably 0.001 to 0.05 mol %, more preferably 0.01 to 0.03 mol %, based on the total molar amount of the alkoxy groups in the metal alkoxide. If the content is less than 0.001 mol %, the catalytic effect is too small, whereas if the content is more than 0.05 mol %, the catalytic effect is too strong, causing the reaction rate to become too fast and tending to become non-uniform.

(Organic solvent)
As the organic solvent, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butanol, etc. can be used.
The sol-gel coating layer can be formed by applying a coating solution consisting of the resin composition once or multiple times by a conventionally known means such as roll coating using a gravure roll coater or the like, spray coating, spin coating, dipping, brushing, bar coding, applicator, or the like, and drying the applied solution.
The packaging material on which the coating liquid has been applied and dried is then heated at 20 to 250° C., preferably 50 to 220° C., for 1 second to 10 minutes.

<Method of manufacturing oxygen-absorbing packaging material for microwave-safe packaging containers>
The method for producing the oxygen absorbing packaging material for a microwave oven-safe packaging container of the present invention using the above-mentioned materials will be described below. The production method shown below is one example and does not limit the present invention.
The lamination of each layer constituting the oxygen-absorbing packaging material for microwave-compatible packaging containers of the present invention can be carried out by any of the lamination methods used in the production of ordinary packaging materials, such as wet lamination, dry lamination, solventless dry lamination, extrusion lamination, T-die coextrusion molding, coextrusion lamination, inflation molding, and the like.
The oxygen-absorbing packaging material for microwave-compatible packaging containers of the present invention can also be subjected to secondary processing for the purpose of imparting surface functions such as chemical functions, electrical functions, magnetic functions, mechanical functions, friction/wear/lubrication functions, optical functions, thermal functions, and biocompatibility.
Examples of secondary processing include embossing, painting, adhesives, printing, metallizing (plating, etc.), machining, surface treatments (antistatic treatments, corona discharge treatments, plasma treatments, photochromic treatments, physical vapor deposition, chemical vapor deposition, coatings, etc.), and the like.
The oxygen-absorbing packaging material for a microwave oven-safe packaging container of the present invention can also be subjected to lamination (dry lamination or extrusion lamination), bag making, and other post-treatments.

When carrying out the above lamination, the surface of each layer can be pretreated, for example, by corona treatment or ozone treatment, as necessary. In addition, anchor coating agents such as isocyanate (urethane), polyethyleneimine, polybutadiene, and organic titanium, or lamination adhesives such as polyurethane, polyacrylic, polyester, epoxy, polyvinyl acetate, cellulose, and others, can be used as desired.

In the present invention, the base layer, the printing ink layer, the printing ink shielding resin layer, the oxygen absorbing adhesive layer, the antioxidant shielding resin layer, and the sealant layer are laminated in this order, the printing ink shielding resin layer, the oxygen absorbing adhesive layer, and the antioxidant shielding resin layer are adjacent to each other, and the metal oxide vapor deposition layer is included on the surface of the base layer or the printing ink shielding resin layer facing the sealant layer, so long as this is the case, the order of formation and lamination of each layer may be arbitrary.
For example, an example will be described in which an oxygen-absorbing packaging material for a microwave-compatible packaging container is produced having a layer structure of a substrate layer [resin film layer/metal oxide vapor deposition layer]/printed ink layer/printed ink-shielding resin layer/oxygen-absorbing adhesive layer/antioxidant-shielding resin layer/sealant layer.
1) A printing ink is printed by gravure printing or the like on the metal oxide vapor deposition surface of a resin film for a base layer on which a metal oxide vapor deposition layer has been deposited, to form a printing ink layer.
2) An adhesive is applied to the surface of the formed printed ink layer and dried to form an adhesive layer, and a resin film for the printing ink shielding resin layer is attached to form the printing ink shielding resin layer.
3) An oxygen-absorbing adhesive composition is applied to the surface of the printing ink-shielding resin layer formed above, and dried to form an oxygen-absorbing adhesive layer. A resin film for the antioxidant-shielding resin layer is then attached to form an antioxidant-shielding resin layer.
4) An adhesive is applied to the surface of the formed antioxidant-shielding resin layer and dried to form an adhesive layer, and a sealant film for the sealant layer is attached to form a sealant layer.
5) If necessary, perform aging treatment.
In this manner, an oxygen-absorbing packaging material for a microwave-safe packaging container can be obtained.

<<Microwave-safe oxygen-absorbing packaging container>>
The microwave-safe oxygen-absorbing packaging container of the present invention is a packaging container made from the oxygen-absorbing packaging material for microwave-safe packaging containers of the present invention.
Specific examples of the microwave-compatible oxygen-absorbing packaging container include pouches, containers consisting of a lid part and a bottom part, molded containers, squeezed containers for ham, etc. In addition, these can be given added value by various shape designs and printing decorations.

Conventional oxygen-absorbing packaging containers made using iron powder-based oxygen-absorbing films are darkly colored by the iron powder-based oxygen absorbent, making it difficult to visually check the contents, making it impossible to inspect the contents using a metal detector or the like, and they cannot be heated in a microwave oven, and there is a concern that moisture may cause rust.
In contrast, the microwave-safe oxygen-absorbing packaging container of the present invention does not contain an iron powder-based oxygen absorber, and therefore the pouch can be made colorless and/or transparent, the contents can be visually confirmed, the contents can be inspected using a metal detector or the like, and the container can be heated in a microwave oven, and there is no need to worry about rust caused by moisture.

Microwave-safe oxygen-absorbing pouch
The microwave-compatible oxygen-absorbing pouch of the present invention is one embodiment of the microwave-compatible oxygen-absorbing packaging container of the present invention, and has a bag-like shape and may be a packaging bag of various shapes. In addition, added value can be added by various shape designs and printing decorations.
Pouches can be made using less material than bottles, making them effective in conserving resources.
Specific examples of the shape of the microwave-compatible oxygen-absorbing pouch include a basic flat pouch, a gusset-type pouch in which the bottom of the pouch spreads out, for example, into a square shape so that the pouch can stand on its own, a refill pouch, a pouch for a small liquid sachet, a pouch for a bag-in-box, a pouch for an infusion bag, a pouch for stick packaging, a spouted pouch in which the spout is attached to the center or upper corner of the pouch, and the like. The addition of a zipper or spout can increase the convenience of inserting and removing the contents and of storing the pouch, but it is preferable for the pouch to have a steam mechanism (46) as shown in FIG. 7.
The flat pouch is a pouch having a flat shape, in which the peripheral portion of the wall film (11a, 11b) is a sealed portion (12), as shown in Fig. 5. It may have one or two notches (13a, 13b).

[Method of making a microwave-safe oxygen-absorbing pouch]
Microwave-safe oxygen-absorbing pouches can be made in a variety of shapes, for example, by folding an oxygen-absorbing packaging material for microwave-safe packaging containers in half, stacking it to encase the contents, or stacking two sheets of oxygen-absorbing packaging material for microwave-safe packaging containers with the sealant layer surfaces facing each other, and then heat-sealing the peripheral edges in various configurations.
Examples of the heat seal type include a side seal type, a two-sided seal type, a three-sided seal type, a four-sided seal type, an envelope seal type, a palm seal type (pillow seal type), a pleated seal type, a flat bottom seal type, a square bottom seal type, and a gusset type.
Examples of the heat sealing method include bar sealing, rotary roll sealing, belt sealing, impulse sealing, high frequency sealing, ultrasonic sealing, and flame sealing.
The microwave-compatible oxygen-absorbing pouch is sealed by heat sealing, so that it has airtightness suitable for heating treatment using a microwave oven.

<Microwave-compatible oxygen-absorbing packaging container comprising a microwave-compatible lid part and a microwave-compatible bottom part>
The microwave-compatible oxygen-absorbing packaging container of the present invention may be, for example, a packaging container made by combining a microwave-compatible oxygen-absorbing lid part and a microwave-compatible oxygen-absorbing bottom part having a recess, as shown in Figure 6.
In a container consisting of a lid part, a bottom part, etc., the sealant layers of the lid part and the bottom part are heat-sealed to face each other and in contact with each other at their fringes.

A recess within the container is capable of receiving contents.
After the contents are placed inside, the flange portion of the bottom part and the film-like lid part are airtightly sealed by heat sealing or bonding with an adhesive, thereby protecting the contents.
By peeling off the cover, the contained contents can be easily removed.

[Microwave-safe oxygen-absorbing lid part]
The oxygen-absorbing lid part for a microwave oven-compatible packaging container of the present invention is a lid part for a microwave oven-compatible packaging container made from the oxygen-absorbing packaging material for a microwave oven-compatible packaging container of the present invention. In addition, added value can be added by various shape designs and printing decorations.
The lid part is in the form of a film, and the oxygen-absorbing packaging material for the lid part of the present invention may have a shape that is approximately identical to the outer periphery of the heat-sealed portion of the bottom part to be combined with it, a shape that is slightly larger than the outer periphery, or a shape that partially protrudes from the outer periphery.

[Microwave-safe oxygen-absorbing base part]
The oxygen-absorbing bottom part for a microwave oven according to the present invention is a bottom part for a microwave oven-compatible packaging container, which is made from the oxygen-absorbing packaging material for a microwave oven-compatible packaging container according to the present invention. In addition, added value can be added by various shape designs and printing decorations.
The base part may be, for example, in the form of a tray having a recess for accommodating the contents and a flange for being heat-sealed to the lid part.

<<Method for producing a microwave-safe oxygen-absorbing packaging container consisting of a lid part and a bottom part>>
The microwave-compatible oxygen-absorbing packaging container of the present invention, which is composed of a microwave-compatible oxygen-absorbing cover part and a microwave-compatible oxygen-absorbing bottom part, can be produced, for example, by the following production method.
The following example is merely one example of a method for producing a microwave-safe oxygen-absorbing packaging container, and the present invention is not limited thereto.
To manufacture the container shown in FIG. 6, first, a tray-shaped bottom part is prepared.
The lid part is then placed on the bottom part with the sealant layer facing the bottom part, and the area where it overlaps with the flange of the bottom part is heat sealed.

Here, when placing the lid part on the base part, one lid part may be placed on one bottom part and heat sealed, or one lid part may be placed over two or more bottom parts and heat sealed. Furthermore, the two or more bottom parts may be cut separately or connected.
In the above, the heat sealing can be performed by a known method such as bar sealing, rotary roll sealing, belt sealing, impulse sealing, high frequency sealing, ultrasonic sealing, flame sealing, etc.

When one lid part is placed on one base part, the lid part may be shaped to match the outer periphery of the flange portion of the base part, may be shaped slightly larger than the outer periphery, or may protrude partially beyond the outer periphery.
In addition, when one lid part is placed over two or more bottom parts, the lid part may be cut into a shape that matches the outer periphery of the flange portion of the bottom parts, a shape that is slightly larger than the outer periphery, or a shape that partially protrudes beyond the outer periphery.
Then, for each individual container, the lid part is cut into a shape that matches the flange portion of the base part and the outer periphery of the lid part.
When contents are to be placed in the container, it is preferable to place the contents in the recess of the bottom part before the above-mentioned heat sealing, and then perform the above-mentioned sheet sealing.

The present invention will be explained in more detail below with reference to examples and comparative examples.

The present invention will be described in more detail with reference to the following examples and comparative examples, but the present invention is not limited to these examples.

<Ingredients>
The main raw materials used in the examples are as follows:
[Raw material for oxygen absorbing compounds]
Polypropylene ether diol 1: SANNIX PP-1000 manufactured by Sanyo Chemical Industries, Ltd. Number average molecular weight: 1000.
Polypropylene ether diol 2: SANNIX PK-400 manufactured by Sanyo Chemical Industries, Ltd. Number average molecular weight: 400.
Hydroxyl-terminated polyisoprene 1: Poly ip, manufactured by Idemitsu Kosan Co., Ltd. Number average molecular weight: 2,500.
Hydroxyl-terminated polybutadiene 1: Poly bd R15HT manufactured by Idemitsu Kosan Co., Ltd. Number average molecular weight: 1200. Hydroxyl-terminated 1,2-addition polymer of 1,3-butadiene.
Toluene diisocyanate 1: Coronate T-65, manufactured by Tosoh Corporation.
Oxygen absorbing compound 1: 3a,4,5,6,7,7a-hexahydro-4,7-methano-1H-inden-6-ol.
- Oxidation promotion catalyst solution 1: Octope AE, manufactured by Hope Pharmaceutical Co., Ltd. A 4% ethyl acetate solution of cobalt octylate, an oxidation promotion catalyst.
- Pro-oxidation catalyst solution 2: Acetop Mn(III) manufactured by Hope Pharmaceutical Co., Ltd. A 10% ethyl acetate solution of manganese acetylacetonate (III), which is a pro-oxidation catalyst.

[glue]
DL Adhesive 1: Two-component curing polyester polyurethane adhesive for dry lamination, Ru-004/H-1, manufactured by Rock Paint Co., Ltd.

[Film for base layer, film for printing ink shielding resin layer]
Transparent vapor-deposited PET film 1: IB-PET manufactured by Dai Nippon Printing Co., Ltd. Transparent one-sided alumina vapor-deposited PET film, 12 μm thick.
PET film 1: Emblet PCBC manufactured by Unitika Ltd., 12 μm thick.

[Printing ink]
Printing ink 1: Rio Alpha R631 white manufactured by Toyo Ink Co., Ltd.

[Antioxidant shielding resin layer film]
Polyamide (nylon) was used to prepare the following polyamide films 1 and 2 by extrusion molding and biaxial stretching.
Polyamide film 1: Biaxially oriented polyamide film, 15 μm thick.
Polyamide film 2: Biaxially oriented polyamide film, 25 μm thick.
PET film 2: E5202 manufactured by Toyobo Co., Ltd., 12 μm thick.

[Antioxidant]
Antioxidant 1: Hindered phenol-based antioxidant Iragnox 1010 manufactured by BASF Japan Ltd.

[Film for sealant layer]
Antioxidant 1 was added by dry blending to polypropylenes having different softening points, and the following CPP films 1, 2, and 3 were produced by extrusion molding.
CPP film 1: Unstretched CPP film. Antioxidant 1 added amount 1000 ppm, thickness 70 μm, softening point 125° C.
CPP film 2: Unstretched CPP film. Antioxidant 1 added amount 1500 ppm, thickness 70 μm, softening point 145° C.
CPP film 3: Unstretched CPP film. Antioxidant 1 added amount 2000 ppm, thickness 70 μm, softening point 165° C.

<<Preparation and Evaluation of Oxygen-Absorbing Adhesive Composition>>
<Preparation of raw material solutions>
(Synthesis of polyol 1 and preparation of polyol solution 1)
The following raw materials were added to a flask equipped with a nitrogen inlet tube, a stirrer, a rectification column, and a condenser, and dehydration condensation was carried out at an internal temperature of 180 to 200° C. with stirring.
Ethylene glycol 53.8 parts by mass Neopentyl glycol 180.3 parts by mass 1,6-hexanediol 204.6 parts by mass Isophthalic acid 287.8 parts by mass Adipic acid 273.5 parts by mass When the acid value of the reaction liquid solid content reached 15 mg KOH/g, the dehydration reaction was further allowed to proceed at 200 to 240° C. while blowing in nitrogen.
When the acid value of the solid content of the reaction liquid became 10 mgKOH/g or less, the internal pressure was reduced to 30 Torr to continue the reaction.
When the acid value of the solid content of the reaction liquid became 3 mgKOH/g or less, the reaction was terminated and the liquid was cooled to room temperature, thereby obtaining Polyol 1.
The number average molecular weight of the resulting polyester polyol, Polyol 1, was 2,000.
Next, polyol 1 was dissolved in ethyl acetate to prepare a polyol solution having a solid content of 60% by mass.

(Synthesis of polyol 2 and preparation of polyol solution 2)
The following raw materials were charged into a flask equipped with a nitrogen inlet tube, a stirrer, and a condenser, and the mixture was heated with stirring to carry out a reflux reaction for 6 hours.
Polypropylene ether diol 1 300.0 parts by mass Polypropylene ether diol 2 250.0 parts by mass Toluene diisocyanate 1 104.0 parts by mass Ethyl acetate 163.5 parts by mass After confirming that the absorption of isocyanate groups had completely disappeared by infrared absorption spectroscopy, the synthesis was terminated and the mixture was cooled to obtain Polyol 2.
The number average molecular weight of the resulting urethane chain extended polyol, Polyol 2, was 2,000.
Next, polyol 2 was dissolved in ethyl acetate to prepare a polyol solution having a solid content of 60% by mass.

(Preparation of Polyisocyanate Solution 1)
The following raw materials were added to a flask equipped with a nitrogen inlet tube, a stirrer, and a condenser and stirred to obtain a polyisocyanate solution 1 having a solids content of 60% by mass.
Hexamethylene diisocyanate (biuret form) 100.0 parts by mass Ethyl acetate 66.7 parts by mass

<Synthesis of oxygen absorbing compound and preparation of oxygen absorbing compound solution>
[Oxygen-absorbing compound 2]
First, the following raw materials were added to a flask equipped with a nitrogen inlet tube, a stirrer, and a condenser, and the mixture was reacted at an internal temperature of 80 to 90° C. for 8 hours with stirring.
Oxygen absorbing compound 1 100.0 parts by mass Isophorone diisocyanate 74.0 parts by mass After confirming that the absorption of isocyanate groups had completely disappeared in the infrared absorption spectrum, the synthesis was terminated and the mixture was cooled, whereby oxygen absorbing compound 2 was obtained.
Then, the oxygen absorbing compound 2 was dissolved in ethyl acetate to prepare an oxygen absorbing compound solution 2 having a solid content of 80 mass %.

[Oxygen-absorbing compound 3]
First, the following raw materials were added to a flask equipped with a nitrogen inlet tube, a stirrer, and a condenser, and the mixture was reacted at an internal temperature of 80 to 90° C. for 8 hours with stirring.
Oxygen absorbing compound 1 100.0 parts by mass Polyisocyanate solution 1 212.5 parts by mass After confirming that the content of NCO groups in the solid content of the reaction liquid by the amine equivalent method reached approximately 0.64% by mass, the synthesis was terminated, the liquid was cooled, and the solvent was removed, thereby obtaining oxygen absorbing compound 3.
Then, the oxygen absorbing compound 3 was dissolved in ethyl acetate to prepare an oxygen absorbing compound solution 3 having a solid content of 60 mass %.

[Oxygen-absorbing compound 4]
First, the following raw materials were added to a flask equipped with a nitrogen inlet tube, a stirrer, and a condenser, and the mixture was reacted at an internal temperature of 80 to 90° C. for 8 hours with stirring.
Oxygen absorbing compound 1 100.0 parts by mass Polyol solution 1 682.3 parts by mass Polyisocyanate solution 1 265.6 parts by mass After confirming that the absorption of the isocyanate group had completely disappeared by infrared absorption spectroscopy, the synthesis was terminated, and the mixture was cooled and the solvent was removed to obtain oxygen absorbing compound 4.
Then, the oxygen absorbing compound 4 was dissolved in ethyl acetate to prepare an oxygen absorbing compound solution 4 having a solid content of 60 mass %.

[Oxygen-absorbing compound 5]
Oxygen absorbing compound 5 was obtained in the same manner as in the above-mentioned oxygen absorbing compound 4, except that polyol solution 2 was used instead of polyol solution 1.
Then, the oxygen absorbing compound 5 was dissolved in ethyl acetate to prepare an oxygen absorbing compound solution 5 having a solid content of 60 mass %.

[Oxygen-absorbing compound 6]
The following raw materials were charged into a flask equipped with a nitrogen inlet tube, a stirrer, and a condenser, and the reaction was carried out for 6 hours at an internal temperature of 80 to 90° C. with stirring.
Hydroxyl-terminated polyisoprene 1 100.0 parts by mass Isophorone diisocyanate 4.7 parts by mass After confirming that the absorption of the isocyanate groups had completely disappeared by infrared absorption spectroscopy, the synthesis was terminated and the mixture was cooled to obtain oxygen-absorbing compound 6, which was a urethane polyol.
The oxygen-absorbing compound 6 thus obtained had a number average molecular weight of 7,000.
Then, the oxygen absorbing compound 6 was dissolved in ethyl acetate to prepare an oxygen absorbing compound solution 6 having a solid content of 60 mass %.

The compositions of the reaction solutions used in synthesizing oxygen-absorbing compounds 2 to 6 are shown in Table 2.
The compositions of oxygen-absorbing compound solutions 2 to 6 are summarized in Table 3.

<Preparation of oxygen-absorbing adhesive composition>
(Preparation of oxygen-absorbing adhesive composition A1)
The following raw materials were mixed at room temperature and homogenized to obtain an oxygen-absorbing adhesive composition A1, which was then subjected to various evaluations.
Oxygen absorbing compound solution 2 100 parts by weight Polyol solution 1 100 parts by weight Polyisocyanate solution 1 10 parts by weight Oxidation promoting catalyst solution 1 1 part by weight Ethyl acetate 140 parts by weight

(Preparation of oxygen-absorbing adhesive compositions A2 to A9, B1 to B2)
According to the formulations in Table 4, oxygen-absorbing adhesive compositions A2 to A9 and B1 to B2 were obtained in the same manner as in the preparation of oxygen-absorbing adhesive composition A1.

<Evaluation of oxygen-absorbing adhesive composition>
A test laminate film was produced using each of the oxygen-absorbing adhesive compositions obtained above, and a simple evaluation of the oxygen-absorbing adhesive composition was carried out.

[Preparation of test laminate film]
The oxygen-absorbing adhesive composition was applied to a PET film 1 using a bar coater so that the dry coating amount was 5.0 g/ ^m2 , and then dried. An LLDPE film 1 was then laminated thereto, nipped on a hot plate at 60°C, and aged at 25°C for 2 days to obtain a laminate film for test specimens.

[Oxygen absorption amount]
The test laminate film was folded in half and three sides were heat sealed to make a packaging bag with inner dimensions of 130 mm x 70 mm. An oxygen sensor chip (Precision Sensing non-destructive oxygen sensor chip) was placed in the packaging bag, and the packaging bag was sealed.
Then, 26 cc of air was injected into the packaging bag using a syringe and the injected part was repaired with adhesive tape. The oxygen concentration was measured at the time of injection and after 14 days of storage in a thermostatic chamber at 25° C., and the amount of oxygen absorbed was calculated.

[Lamination strength]
A rectangular test piece having a width of 15 mm was prepared from the test laminate film obtained above, and the laminate strength between the PET film 1 and the LLDPE film 1 was measured using a tensile tester at a pulling speed of 50 mm/min.

[Odor]
After the oxygen absorbency was measured, the packaging bag was opened and the odor was evaluated sensorily according to the following evaluation criteria.
Evaluation criteria:
0: No odor 1: Faint odor 2: Weak odor 3: Medium odor 4: Strong odor

<<Production and evaluation of oxygen-absorbing packaging materials>>

<Evaluation method for oxygen absorbing packaging materials>
[Heat sealability]
Two pieces of packaging material measuring 100 mm x 100 mm were cut out from the obtained packaging material, and these were overlapped with the sealant layer surfaces facing each other. Using a heat seal tester (TP-701-A manufactured by Tester Sangyo Co., Ltd.), an area of 10 mm x 100 mm was heat sealed under the following conditions, and a test piece for peel strength was prepared in which the ends were not heat sealed or bonded and were divided into two.
This test piece was cut into a strip of 15 mm width, and each bifurcated end was attached to a tensile tester to measure the peel strength (N/15 mm) under the conditions described below, and the pass/fail judgment was made according to the pass/fail judgment criteria described below.
Heat sealing conditions Temperature: 200°C
Pressure: 1 kgf/ ^cm2
Time: 1 second Test conditions Test speed: 300 mm/min Load range: 50 N
Pass/fail criteria: ◯: 15N/15mm or more, passed.
×: Less than 15N/15mm, failure.

[Interlayer Adhesion]
A rectangular test piece measuring 15 mm x 100 mm was cut out from the obtained packaging material, and the adhesive strength between the layers sandwiching the oxygen-absorbing adhesive layer was measured using a tensile tester at a pulling speed of 50 mm/min.
Pass/fail criteria: ◯: 3N/15mm or more, passed.
×: Less than 3N/15mm, not acceptable.

[Dissolved oxygen content]
A pouch with inner dimensions of 110 mm x 150 mm was made from the obtained packaging material, and 180 mL of drinking water and an oxygen sensor chip (non-destructive oxygen sensor chip manufactured by Precision Sensing) were sealed inside the pouch. The amount of dissolved oxygen in the pouch immediately after boiling and retorting treatment (121°C, 30 minutes) was measured using a non-destructive oxygen concentration meter (non-destructive oxygen concentration meter manufactured by Presence: FIBOX4 OXYGEN METER) to determine whether it passed or failed.
Pass/fail criteria: ◯: 3 ppm or less, passed.
×: Exceeds 3 ppm and is unacceptable.

[Microwave resistance]
A pouch with an inner dimension of 110 mm x 150 mm was made from the obtained packaging material, and the pouch was filled with water and heated in a microwave oven at 600 W for 2 minutes, and the presence or absence of holes in the pouch was detected visually. The meanings of the descriptions in the table are as follows.
○: No holes, passed.
×: Holes present, failure.

[Changes in odor and taste of liquid contents]
After the above-mentioned measurement of the amount of dissolved oxygen, the drinking water inside the pouch was subjected to a sensory evaluation of the odor and taste according to the following evaluation criteria.
Evaluation criteria:
0: Tasteless and odorless 1: Faint odor 2: Weak odor 3: Medium odor 4: Strong odor

[Example 1]
On the metal oxide vapor-deposited layer surface of transparent vapor-deposited PET film 1, printing ink 1 was printed by gravure printing so as to give a dry coating amount of 2 g/m ² to form a printed ink layer.
Next, DL adhesive 1 was applied to the printed ink layer surface so that the dry coating amount was 4 g/m ² and dried, and then PET film 1 was laminated thereon by a dry lamination method to obtain laminated film 1.
Then, oxygen-absorbing adhesive composition A1 was applied to the PET film 1 surface of the obtained laminated film 1 so that the dry coating amount was 4 g/ ^m2 and dried, and then PET film 2 was bonded thereto by a dry lamination method to obtain laminated film 2.
Next, DL adhesive 1 was applied to the PET film 2 surface of the obtained laminated film 2 so that the dry coating amount was 4 g/ ^m2 and dried, and then CPP film 1 was laminated by a dry lamination method and aged at 40°C for 3 days to obtain an oxygen-absorbing packaging material for microwave-compatible packaging containers having the following layer structure, and various evaluations were carried out.
Layer structure: transparent vapor-deposited PET film 1 (12 μm thick) [PET film layer/transparent alumina vapor-deposited layer]/printing ink layer (2 g/m ² )/DL adhesive 1 (4 g/m ² )/PET film 1 (12 μm thick)/oxygen-absorbing adhesive composition A1 (4 g/m ² )/PET film 2 (12 μm thick)/DL adhesive 1 (4 g/m ² )/CPP film 1 (70 μm thick)

[Example 2]
Printing ink 1 was printed on PET film 1 by gravure printing so that the dry coating amount was 2 g/m ² to form a printed ink layer.
Next, DL adhesive 1 was applied to the printed ink layer surface to a dry coating amount of 4 g/ ^m2 and dried, and then the PET surface of transparent vapor-deposited PET film 1 was bonded thereto by dry lamination to obtain laminated film 1.
Next, oxygen-absorbing adhesive composition A1 was applied to the metal oxide vapor deposition layer surface of the obtained laminated film 1 so that the dry coating amount was 4 g/ ^m2 and dried, and then PET film 2 was bonded thereto by a dry lamination method to obtain laminated film 2.
Next, DL adhesive 1 was applied to the PET film 2 surface of the obtained laminated film 2 so that the dry coating amount was 4 g/ ^m2 and dried, and then CPP film 1 was laminated by a dry lamination method and aged at 40°C for 3 days to obtain an oxygen-absorbing laminate for a microwave-compatible packaging container having the following layer structure, and various evaluations were carried out.
Layer structure: PET film 1 (12 μm thick)/printed ink layer (2 g/m ² )/DL adhesive 1 (4 g/m ² )/transparent vapor-deposited PET film 1 (12 μm thick) [PET film layer/transparent alumina vapor-deposited layer]/oxygen-absorbing adhesive composition A1 (4 g/m ² )/PET film 2 (12 μm thick)/DL adhesive 1 (4 g/m ² )/CPP film 1 (70 μm thick)

[Example 3]
An oxygen absorbing laminate for a microwave oven compatible packaging container was obtained in the same manner as in Example 1, except that the PET film 2 in Example 1 was changed to the polyamide film 1, and various evaluations were similarly carried out.
Layer structure: transparent vapor-deposited PET film 1 (12 μm thick) [PET film layer/transparent alumina vapor-deposited layer]/printing ink layer (2 g/m ² )/DL adhesive 1 (4 g/m ² )/PET film 1 (12 μm thick)/oxygen-absorbing adhesive composition A1 (4 g/m ² )/polyamide film 1 (15 μm thick)/DL adhesive 1 (4 g/m ² )/CPP film 1 (70 μm thick)

[Example 4]
A laminate was obtained in the same manner as in Example 3, except that the polyamide film 1 in Example 3 was changed to the polyamide film 2, and various evaluations were similarly carried out.
Layer structure: transparent vapor-deposited PET film 1 (12 μm thick) [PET film layer/transparent alumina vapor-deposited layer]/printing ink layer (2 g/m ² )/DL adhesive 1 (4 g/m ² )/PET film 1 (12 μm thick)/oxygen-absorbing adhesive composition A1 (4 g/m ² )/polyamide film 2 (25 μm thick)/DL adhesive 1 (4 g/m ² )/CPP film 1 (70 μm thick)

[Example 5]
Except for changing CPP film 1 in Example 1 to CPP film 2, an oxygen absorbing laminate for a microwave oven compatible packaging container was obtained in the same manner as in Example 1, and various evaluations were carried out in the same manner. Layer structure: transparent vapor-deposited PET film 1 (12 μm thick) [PET film layer/transparent alumina vapor-deposited layer]/printing ink layer (2 g/m ² )/DL adhesive 1 (4 g/m ² )/PET film 1 (12 μm thick)/oxygen absorbing adhesive composition A1 (4 g/m ² )/PET film 2 (12 μm thick)/DL adhesive 1 (4 g/m ² )/CPP film 2 (70 μm thick)

[Example 6]
A laminate was obtained in the same manner as in Example 1, except that CPP film 1 in Example 1 was changed to CPP film 3, and various evaluations were similarly carried out.
Layer structure: transparent vapor-deposited PET film 1 (12 μm thick) [PET film layer/transparent alumina vapor-deposited layer]/printing ink layer (2 g/m ² )/DL adhesive 1 (4 g/m ² )/PET film 1 (12 μm thick)/oxygen-absorbing adhesive composition A1 (4 g/m ² )/PET film 2 (12 μm thick)/DL adhesive 1 (4 g/m ² )/CPP film 3 (70 μm thick)

[Comparative Example 1]
A laminate was obtained in the same manner as in Example 1, except that the oxygen-absorbing adhesive composition A1 in Example 1 was replaced with DL adhesive 1, and various evaluations were similarly carried out.
Layer structure: transparent vapor-deposited PET film 1 (12 μm thick) [PET film layer/transparent alumina vapor-deposited layer]/printing ink layer (2 g/m ² )/DL adhesive 1 (4 g/m ² )/PET film 1 (12 μm thick)/DL adhesive 1 (4 g/m ² )/PET film 2 (12 μm thick)/DL adhesive 1 (4 g/m ² )/CPP film 1 (70 μm thick)

[Comparative Example 2]
On the metal oxide vapor-deposited layer surface of transparent vapor-deposited PET film 1, printing ink 1 was printed by gravure printing so as to give a dry coating amount of 2 g/m ² to form a printed ink layer.
Next, oxygen-absorbing adhesive composition A1 was applied to the surface of the printed ink layer to a dry coating amount of 4 g/ ^m2 and dried, after which CPP film 1 was attached by dry lamination and aged at 40°C for 3 days to obtain a laminate having the layer structure described below, and various evaluations were similarly performed.
Layer structure: transparent vapor-deposited PET film 1 (12 μm thick) [PET film layer/transparent alumina vapor-deposited layer]/printed ink layer (2 g/m ² )/oxygen-absorbing adhesive composition A1 (4 g/m ² )/CPP film 1 (70 μm thick)

<Summary of results>
The oxygen-absorbing packaging materials for microwave-compatible packaging containers of all the Examples of the present invention exhibited an excellent balance of heat sealability, interlayer adhesion, oxygen absorption, microwave resistance, and resistance to changes in odor and taste of the liquid contents.
On the other hand, the packaging material of Comparative Example 1, which did not include an oxygen-absorbing adhesive layer, the packaging material of Comparative Example 2, which did not include a printing-ink-shielding resin layer, the packaging material of Comparative Example 3, which had a poor effect of the printing-ink-shielding resin layer, and the packaging material of Comparative Example 4, which had a poor effect of the antioxidant-shielding resin layer, showed poor oxygen absorption properties.

1 Oxygen-absorbing packaging material for microwave-compatible packaging container 2 Base layer 2a Resin film layer 2b Metal oxide vapor deposition layer 3 Printing ink layer 4 Printing ink shielding resin layer 4a Resin film layer 4b Metal oxide vapor deposition layer 5 Oxygen-absorbing adhesive layer 6 Antioxidant shielding resin layer 7 Sealant layer 8 Adhesive layer 10 Microwave-compatible oxygen-absorbing flat pouch 11a, 11b Wall film 12 Sealed portion 13a, 13b Notch 20 Microwave-compatible oxygen-absorbing packaging container 21 Microwave-compatible oxygen-absorbing bottom part 22 Contents-accommodating recess 23 Flange portion 24 Microwave-compatible oxygen-absorbing lid part 40 Microwave-compatible oxygen-absorbing retort pouch 41a, 41b Wall film 42 Heat-sealed portion 43 Bottom gusset portion 44 Opening 45 Notch for opening 46 Steam mechanism 46a Unheat-sealed portion 46b Separation heat-sealed portion

Claims (7)

A microwaveable oxygen-absorbing packaging material having, in this order, at least a base layer, a printing ink layer, a printing ink-shielding resin layer, an oxygen-absorbing adhesive layer, an antioxidant-shielding resin layer, and a sealant layer,
The substrate layer and/or the printing ink shielding resin layer includes a metal oxide vapor deposition layer on the surface on the sealant layer side,
The printing ink shielding resin layer includes a polyester-based resin layer,
The oxygen-absorbing adhesive layer is a layer made of an oxygen-absorbing adhesive composition containing at least an oxygen-absorbing compound and an oxidation-promoting catalyst,
The antioxidant-shielding resin layer contains a polyester resin or a polyamide resin,
The sealant layer contains a polyolefin resin and an antioxidant,
The oxygen absorbing compound has one or more unsaturated five-membered rings,
Any bond between the five carbon atoms constituting the unsaturated five-membered ring is a carbon-carbon double bond;
A monovalent and/or divalent or higher electron-donating organic group 1 is bonded to the unsaturated five-membered ring;
When there is one unsaturated five-membered ring, the five-membered ring or the organic group 1 has a functional group having an active hydrogen or a group in which the active hydrogen of the functional group having an active hydrogen is substituted with a monovalent organic group 2,
A microwave-safe oxygen-absorbing packaging material, characterized in that when there are two or more unsaturated five-membered rings, the unsaturated five-membered rings are bonded to each other via a divalent or higher organic group 2 that replaces the active hydrogen of the active hydrogen group on each of the five-membered rings or the organic group 1. The oxygen absorbing adhesive composition further contains a modifier,
2. The microwave-safe oxygen-absorbing packaging material according to claim 1, wherein the modifying agent contains an isocyanate compound and/or a hydroxyl group-containing compound. The microwave-safe oxygen-absorbing packaging material according to claim 1, characterized in that the polyolefin resin is a polypropylene resin. The substrate layer and/or the printing ink shielding resin layer further includes a sol-gel coating layer on a surface of the metal oxide vapor deposition layer facing the sealant layer,
2. The microwave-safe oxygen-absorbing packaging material according to claim 1, wherein the sol-gel coating layer is a layer formed from a resin composition containing a metal alkoxide, a water-soluble polymer, a sol-gel catalyst, water, an organic solvent, and the like. 2. The microwave-safe oxygen-absorbing packaging material according to claim 1, wherein the oxygen-absorbing compound contains one or more compounds selected from the group consisting of compounds represented by the following formulas (1) to (5):

(In the formula, each of a to e is a number of 1 or more, f is a number of 0 or more, and each of R ¹ , R ² , R ³ , R ⁴ , and R ⁵ is an organic group having 1 or more carbon atoms. Each of R ¹ , R ² , R ³ , R ⁴ , and R ⁵ may contain at least an alkylene and/or phenylene structure, and may contain a structure derived from one or more selected from the group consisting of polyhydric alcohols, polyolefin polyols, polyether polyols, polyester polyols, polycarbonate polyols, poly(meth)acrylic acid ester polyols, phenoxy resins, and urethane chain-extended polyols thereof.) A microwave-safe oxygen-absorbing packaging container, comprising the microwave-safe oxygen-absorbing packaging material according to any one of claims 1 to 5. A microwave-safe oxygen-absorbing packaging bag, characterized in that it is made of the microwave-safe oxygen-absorbing packaging material described in any one of claims 1 to 5.

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