JP7775655B2 - Oxygen-absorbing laminate for microwave-safe packaging containers - Google Patents

Description

The present invention relates to an oxygen-absorbing laminate for microwave-compatible packaging containers that generates little odor, inhibits the permeation of oxygen gas from the outside, and inhibits oxygen-induced deterioration of the contents by absorbing oxygen within the contents storage space. It also has an excellent balance of aroma retention, content resistance, interlayer adhesive strength, heat sealability, odor generation amount, and oxygen absorption performance, making it suitable for filling and packaging. It also relates to an oxygen-absorbing packaging material for microwave-compatible packaging containers and a microwave-compatible oxygen-absorbing packaging container made from the oxygen-absorbing laminate for microwave-compatible packaging containers.

Conventional packaging methods to prevent oxygen-induced quality deterioration of contents such as food, medicine, chemical products, and cosmetics have included using packaging materials with high oxygen barrier properties, replacing the gas in the content storage area with an inert gas such as nitrogen gas, or including an oxygen absorber packaged with reduced iron powder or the like. However, these methods have problems such as insufficient performance, increased packaging costs, increased waste, only functioning in moist environments, and the risk of accidental ingestion.
Conventional oxygen-absorbing laminates or oxygen-absorbing packaging materials contain an oxygen absorber, which includes an organic compound or a metal-based oxygen absorber such as iron powder, and the oxygen absorber itself oxidizes to absorb oxygen in the content storage space.
Furthermore, in many cases, the oxygen absorbing layer containing the oxygen absorber is disposed in a layer closer to the contents-accommodating space, for example, in a layer adjacent to the 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 oxygen absorption efficiency.
Furthermore, when the oxygen absorber is a metal-based oxygen absorber, the above-mentioned interference 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 seen, making it impossible to inspect the contents using a metal detector or the like. Although the packaging can be heated in a microwave oven, 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 retorted, but the sealant layer is made of a special highly heat-resistant polyethylene resin that is difficult to obtain, and this has problems with its versatility.
Furthermore, Patent Document 2 also describes the development of a packaging material using a resin that has oxygen absorbing properties and emits little odor. However, this resin is polycyclododecene, which is insoluble in polar solvents and does not have an active hydrogen group, and therefore is 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 using methyltetrahydrophthalic acid as a raw material having oxygen absorbing properties, but it has the drawback of being unstable and having low oxygen absorbing properties.
Patent Document 4 describes an oxygen-absorbing resin that is a thermoplastic resin having a repeating unit consisting of saturated five-membered rings having a substituent containing a carbon-carbon double bond and a —CH═CH— group connecting the saturated five-membered rings. However, the resin has drawbacks such as being difficult to use due to poor solubility in solvents and emitting a strong odor.

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

The objective of the present invention is to provide an oxygen-absorbing laminate for microwave-compatible packaging containers that generates little odor and has excellent oxygen gas barrier properties, oxygen absorption properties, interlayer adhesive strength, and heat sealability, as well as an oxygen-absorbing packaging material for microwave-compatible packaging containers and a microwave-compatible oxygen-absorbing packaging container made from the oxygen-absorbing laminate for microwave-compatible packaging containers, which have excellent resistance to microwave heating, inhibit the permeation of oxygen gas from the outside, and absorb oxygen within the content storage space to inhibit oxygen-induced deterioration and changes in odor and taste of the contents, and have an excellent balance between aroma retention and content resistance.

Therefore, in order to solve the above problem, the inventors discovered that an oxygen-absorbing laminate for a microwave-compatible packaging container, which comprises, in this order, at least a base layer, a specific inorganic oxygen barrier layer, an oxygen-absorbing adhesive layer made of a specific oxygen-absorbing adhesive, a shielding resin layer, and a sealant layer, can solve the above problem.
That is, the present invention is characterized by the following points.
1. An oxygen-absorbing laminate for a microwave-safe packaging container, comprising at least a substrate layer, an inorganic oxygen barrier layer, an oxygen-absorbing adhesive layer, a shielding resin layer, and a sealant layer, in this order,
the inorganic oxygen barrier layer comprises a metal oxide;
the oxygen-absorbing adhesive layer is a layer formed from an oxygen-absorbing adhesive composition,
The oxygen-absorbing adhesive composition contains at least an oxygen-absorbing compound and an oxidation-promoting catalyst,
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,
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 an active hydrogen of an active hydrogen group on each of the five-membered rings or the organic group 1,
the shielding resin layer contains one or more resins selected from the group consisting of nylon-based resins, polyolefin-based resins, and polyester-based resins;
the sealant layer contains a polyolefin resin and an antioxidant,
The polyolefin resin has a softening point of 120°C or higher and 170°C or lower.
2. The oxygen-absorbing laminate for a microwave-safe packaging container according to 1 above, wherein the unsaturated five-membered ring structure or the structure consisting of the unsaturated five-membered ring and organic group 1 is derived from one or more members selected from the group consisting of cyclopentadiene, dicyclopentadiene, norbornene, and derivatives thereof.
3. The oxygen-absorbing laminate for a microwave-safe packaging container according to 1 or 2 above, wherein the organic group 2 contains a structural portion derived from an isocyanate compound, or a combination of an isocyanate compound and a hydroxyl group-containing compound.
4. The oxygen-absorbing laminate for a microwave-safe packaging container according to claim 3, wherein the isocyanate compound is one or more compounds selected from the group consisting of xylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, and derivatives thereof. 5. The oxygen-absorbing laminate for a microwave-safe packaging container according to claim 3 or 4, wherein the hydroxyl group-containing compound is one or more compounds 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. The oxygen-absorbing laminate for a microwave-safe packaging container according to any one of 1 to 5 above, wherein the organic group 2 does not have a crosslinkable functional group.
7. The organic group 2 has one or more crosslinkable functional groups,
6. The oxygen-absorbing laminate for a microwave-safe packaging container according to any one of 1 to 5 above, wherein the crosslinkable functional group is a hydroxyl group and/or an isocyanate group.
8. The oxygen-absorbing laminate for a microwave-compatible packaging container according to any one of 1 to 5 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 (4):
(In the formula, a to e are each a number of 1 or more, and each of R ¹ , R ² , and R ³ is an organic group having 1 or more carbon atoms, containing at least an alkylene and/or phenylene structure, and may further contain a structure derived from one or more members selected from the group consisting of polyhydric alcohols, polyolefin polyols, polyether polyols, polyester polyols, polycarbonate polyols, poly(meth)acrylate polyols, phenoxy resins, and urethane chain-extended polyols thereof.)
9. The oxygen-absorbing laminate for a microwave-safe packaging container according to any one of 1 to 5 above, wherein the oxygen-absorbing compound contains a compound represented by the following formula (5):
(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 and containing 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)acrylate polyols, phenoxy resins, and urethane chain-extended polyols thereof.)
10. The oxygen-absorbing laminate for a microwave-safe packaging container according to any one of 1 to 9 above, wherein the oxidation-promoting catalyst is a peroxide or a compound containing a cation made of a transition metal.
11. The oxygen-absorbing laminate for a microwave-safe packaging container according to any one of 1 to 10 above, wherein the compound containing a cation made of a transition metal is a metal soap made of a transition metal compound capable of releasing a cation or complex made of a transition metal, and an anion or ligand made of a fatty acid.
12. The oxygen-absorbing adhesive composition further contains a modifier,
12. The oxygen-absorbing laminate for a microwave-safe packaging container according to any one of 1 to 11 above, wherein the modifying agent contains an isocyanate compound and/or a hydroxyl group-containing compound.
13. The oxygen-absorbing laminate for a microwave-compatible packaging container according to 12 above, wherein the isocyanate compound is one or more compounds selected from the group consisting of xylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, and derivatives thereof.
14. The oxygen-absorbing laminate for a microwave-safe packaging container according to 12 or 13 above, wherein the hydroxyl group-containing compound comprises one or more compounds selected from the group consisting of polyester polyols, poly(meth)acrylate polyols, polyalkylene ether diols, and urethane chain-extended polyols thereof.
15. The total light transmittance is 80 or more,
The haze value is 40 or less,
15. The oxygen-absorbing laminate for a microwave-safe packaging container according to any one of 1 to 14 above, which is transparent.
16. An oxygen-absorbing packaging material for a microwave-safe packaging container, characterized in that it is produced using the oxygen-absorbing laminate for a microwave-safe packaging container according to any one of 1 to 15 above.
17. A microwave-safe, oxygen-absorbing packaging container, characterized in that it is produced using the oxygen-absorbing packaging material for a microwave-safe packaging container according to 16 above.
18. A microwave-safe, oxygen-absorbing pouch, characterized by being produced using the oxygen-absorbing packaging material for a microwave-safe packaging container according to 16 above.

According to the present invention, it is possible to obtain an oxygen-absorbing laminate for a microwave-compatible packaging container that generates little odor and has excellent oxygen gas barrier properties, oxygen absorption properties, interlayer adhesive strength, and heat sealing properties, as well as an oxygen-absorbing packaging material for a microwave-compatible packaging container and a microwave-compatible packaging container that are made from the oxygen-absorbing laminate for a microwave-compatible packaging container, have excellent resistance to microwave heating, inhibit the permeation of oxygen gas from the outside, and inhibit oxygen-induced deterioration of the contents by absorbing oxygen in the content storage space, and have an excellent balance between aroma retention and content resistance.
Furthermore, the oxygen-absorbing laminate for microwave-compatible packaging containers and the oxygen-absorbing packaging material for microwave-compatible packaging containers of the present invention shorten the packaging process, reduce costs, and make the microwave-compatible oxygen-absorbing packaging containers lighter.Since the microwave-compatible oxygen-absorbing packaging containers do not require the inclusion of oxygen absorbers that were previously included, this eliminates the risk of the oxygen absorbers being accidentally ingested and reduces the amount of waste caused by the oxygen absorbers.

1 is a cross-sectional view showing an example of the layer structure of an oxygen-absorbing laminate for a microwave-safe 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. 1 is a cross-sectional view of a microwave-safe oxygen-absorbing packaging container comprising a microwave-safe lid part and a microwave-safe bottom part, which is one embodiment of the microwave-safe oxygen-absorbing packaging container of the present invention. 1 is an external view showing a microwave-safe, oxygen-absorbing retort pouch, which is one embodiment of the microwave-safe, 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 food is heated at 90 to 135° C. under 1 to 3 atmospheres.

<<Oxygen-absorbing laminate for microwave-safe packaging containers>>
The oxygen-absorbing laminate for a microwave-safe packaging container of the present invention has a layer structure including at least a substrate layer, an inorganic oxygen barrier layer, an oxygen-absorbing adhesive layer, a shielding resin layer, and a sealant layer, in this order.
In a microwave-safe oxygen-absorbing packaging container produced using the oxygen-absorbing laminate for a microwave-safe packaging container, the sealant layer is heat-sealed and the inorganic oxygen barrier layer is positioned outside the oxygen-absorbing adhesive layer.
By positioning the inorganic oxygen barrier layer outside the oxygen-absorbing adhesive layer, oxygen is prevented from penetrating the packaging material from the outside, and the efficiency with which the oxygen-absorbing adhesive layer absorbs oxygen in the content storage space and reduces the oxygen concentration can be increased.
Furthermore, since the oxygen-absorbing adhesive layer is not adjacent to the sealant layer, with a shielding resin layer between them, and the migration of various additives contained in the sealant layer to the oxygen-absorbing adhesive layer is suppressed by the shielding resin layer, a decrease in the oxygen absorption efficiency of the oxygen-absorbing adhesive layer is suppressed.
Furthermore, the oxygen-absorbing adhesive layer in the present invention is a layer formed from an oxygen-absorbing adhesive composition containing an oxygen-absorbing compound, which is an organic compound, and an oxidation-promoting catalyst, and is not a layer containing a metallic oxygen absorber such as iron powder, so there is no dark coloring due to the metallic oxygen absorber.When an inorganic oxygen barrier layer of a transparent vapor-deposited film made of a specific metal oxide such as alumina is used, the contents inside the package can be seen, the contents can be inspected using a metal detector, etc., the package can be heated in a microwave oven, and there is no concern about rust due to moisture.
The sealant layer contains a heat-sealable resin. In the case of a packaging material for a microwave-safe packaging container, microwave heating is required for thermal sterilization, so a resin of a grade having high heat resistance and resistance to oxidation and deterioration may be used, or an antioxidant or the like may be added to enhance the heat resistance and resistance to oxidation and deterioration.
Specifically, the softening point of the sealant layer is preferably 120° C. or higher.
The oxygen-absorbing laminate for a microwave-safe packaging container of the present invention preferably has a total light transmittance of 80 or more and a haze value of 40 or less, and is transparent.

The oxygen-absorbing laminate for a packaging container to be heated in a microwave oven may further include various functional layers having various functions, as required, such as an auxiliary barrier layer, an aroma-retaining layer, a light-shielding layer, and a reinforcing layer.
Furthermore, a general-purpose adhesive layer may be included between or within each of the above layers to improve interlayer adhesion.

[Contents]
In the above, examples of contents include, but are not limited to, foods such as coffee beans, tea leaves, cheese, snacks, rice crackers, fresh and semi-fresh sweets, fruits, nuts, vegetables, fruits, fish and meat products, paste products, dried fish, smoked foods, tsukudani (foods boiled in soy sauce), raw rice, cooked rice, rice cakes, baby foods, jam, mayonnaise, ketchup, cooking oil, dressings, sauces, spices, dairy products, pet food, beverages such as beer, wine, fruit juice, green tea, and coffee, pharmaceuticals, cosmetics, shampoos and conditioners, detergents, metal parts, and electronic parts.

<About the layers that make up the oxygen-absorbing laminate for microwave-safe packaging containers>

≪Base material layer≫
The material for the substrate layer can be a commonly known and commonly used resin film that has excellent mechanical, physical, chemical, and other properties, and is particularly strong, tough, and heat-resistant. 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 may be composed of two or more layers of the same or different compositions laminated by any lamination means.
The thickness of the base material 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, the thickness of the base material layer is preferably 5 μm to 100 μm, more preferably 10 μm to 50 μm, and even more preferably 15 to 25 μm.

Specific examples of the resin film include resin films made of tough thermoplastic resins such as polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate, polyolefin resins such as polypropylene, polyamide resins such as nylon, polyaramid resins, polycarbonate resins, polyacetal 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, biaxially oriented PET film and biaxially oriented nylon film are preferably used.

The paper substrate can be one that can impart shapeability, flex resistance, rigidity, etc., and for example, a paper substrate for a paper layer that is bleached or unbleached and has strong sizing properties, or a paper substrate such as pure white roll paper, kraft paper, paperboard, coated paper, processed paper, milk base paper, etc. can be used.
The paper substrate 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 .

If necessary, plastic compounding agents and additives such as lubricants, crosslinking agents, antioxidants, ultraviolet absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, and pigments may be added to the resin film used in the base layer for the purpose of improving or modifying processability, heat resistance, weather resistance, mechanical properties, dimensional stability, antioxidant properties, slip properties, release properties, flame retardancy, mildew resistance, electrical properties, strength, etc., and the amount of these additives may be arbitrarily added depending on the purpose, as long as it does not adversely affect other properties.
The substrate layer can be laminated to another layer 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 comes into contact with the adhesive can be previously subjected 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 oxidation treatment using chemicals.

<Inorganic oxygen barrier layer>
The inorganic oxygen barrier layer is a layer that inhibits oxygen from passing from the outside of the package to the contents-storing section inside the package in a package made using the oxygen-absorbing laminate for a microwave-safe packaging container.
In a microwave-compatible oxygen-absorbing pouch made using an oxygen-absorbing laminate for a microwave-compatible packaging container, the inorganic oxygen barrier layer is positioned outside the oxygen-absorbing adhesive layer, which prevents oxygen from entering from outside the package and enhances the effect of the oxygen-absorbing adhesive layer absorbing oxygen in the content storage section inside the package to reduce the oxygen concentration.
For the inorganic oxygen barrier layer, various oxygen barrier materials can be used, such as inorganic vapor deposition films containing one or more materials selected from the group consisting of metal oxides, metal nitrides, and metal carbides.
Furthermore, the material may be an oxygen barrier material that has barrier properties not only against oxygen but also against water vapor, light blocking properties against sunlight, aroma retention properties for the contents, etc. Alternatively, barrier materials having these barrier properties may be used in combination.

Among the above, metal oxide vapor-deposited films vapor-deposited on a resin film constituting the base layer are particularly preferred because they easily provide excellent barrier properties against oxygen gas, water vapor, light blocking properties, aroma retention properties, etc., and have the advantage of being environmentally friendly in terms of disposal of the container.
Furthermore, in the case of a vapor deposition film made of a specific metal oxide, such as alumina (aluminum oxide), the inorganic oxygen barrier layer and the laminate can be made transparent, which makes it possible to visually check the contents inside the package, inspect the contents using a metal detector, etc., heat the package in a microwave oven, and eliminates the risk of rust due to moisture.

Specific examples of metal elements that make up the inorganic compounds such as the metal oxides, metal nitrides, and metal carbides mentioned above include 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).

Specific examples of inorganic compounds include metal oxides, metal nitrides, and metal carbides made of the above metal elements, as well as composite inorganic compounds such as indium tin oxide (ITO) and SiO _x C _y films prepared by chemical vapor deposition or the like.
Specific examples of inorganic compounds for the inorganic vapor deposition layer include silica (silicon oxide), alumina (aluminum oxide), silicon nitride, silicon carbide, etc. Among these, silica and alumina are preferred.

The average composition of inorganic compounds is expressed as _MOx or _MOxCy (wherein M represents a metal element and the values of x and y vary depending on the metal element ₎ , such as _SiOx , _{AlOx , SiOxCy} , etc. In the case of metal oxides, the value of X can range from 0 to 2 for silicon, 0 to 1.5 for aluminum, 0 to 1 for magnesium, 0 to 1 for calcium, 0 to 0.5 for potassium, 0 to 2 for tin, 0 to 0.5 for sodium, 0 to 1.5 for boron, 0 to 2 for titanium, 0 to 1 for lead, 0 to 2 for zirconium, and 0 to 1.5 for yttrium.
In the above MO _x , when x=0, the material is metallic and not transparent, and the upper limit of the range of x is the value when the material is completely oxidized.
In the present invention, silicon oxide and aluminum oxide are preferably used, and silicon oxide having an x value in the range of 1.0 to 2.0 and aluminum oxide having an x value in the range of 0.5 to 1.5 can be used.
The inorganic oxygen barrier layer may be formed of one of these barrier materials, or a combination of two or more of them, or a mixture of two or more of them. It may also 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 need to be laminated adjacently.

Since the resin film supporting the inorganic oxygen barrier layer has a vapor-deposited layer of an inorganic compound formed thereon, it is preferable to use a resin film that has excellent mechanical, physical, chemical, and other properties, and is particularly strong and tough, and has heat resistance.
The resin film supporting the inorganic oxygen barrier layer may be the resin film constituting the substrate layer, or may be another resin film.
When the inorganic oxygen barrier layer is adhered to the resin film, it can be laminated by adhering via an oxygen absorbing adhesive composition or a general-purpose adhesive layer.
When laminating a resin film with an inorganic vapor deposition layer, if necessary, in order to strengthen the adhesive strength with other layers, the surface of the resin film with an inorganic vapor deposition layer may 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 oxidation treatment using chemicals, to form a surface treatment layer.

Specifically, in the present invention, examples of the resin film supporting the inorganic vapor deposition layer 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, 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, fluorine-based resins, and others.
Among the above resins, it is particularly preferable to use a film of a polypropylene-based resin, a polyester-based resin, or a polyamide-based resin.

The resin film supporting the inorganic vapor deposition layer can be an oxygen barrier resin coating film or an oxygen barrier resin film made of an oxygen barrier resin, and can also exhibit gas barrier properties against water vapor and the like, aroma retention properties, and the like.
Examples of oxygen barrier resins that can be used include films or coatings of resins with excellent gas barrier properties, such as polyvinylidene chloride resins (PVDC), polyester resins, polyamide resins (particularly aromatic polyamides such as nylon MXD6), ethylene-vinyl alcohol copolymers (EVOH) with an ethylene content of 25 mol % to 50 mol % obtained by fully saponifying ethylene-vinyl acetate copolymers (vinyl acetate is approximately 79 wt % to 92 wt %), polyvinyl alcohol, polyacrylonitrile, and others.
The thickness of the resin film supporting the inorganic vapor deposition layer is not particularly limited, but is preferably 0.5 μm to 300 μm, and more preferably 1 μm to 100 μm.

The inorganic vapor deposition layer can be formed on a resin film using the inorganic compounds described above as raw materials, for example, by physical vapor deposition (PVD) methods such as vacuum deposition, sputtering, ion plating, and cluster ion beam deposition, or chemical vapor deposition (CVD) methods such as plasma-enhanced chemical vapor deposition, thermal chemical vapor deposition, and photochemical vapor deposition.

More specifically, in the above-mentioned PVD method, for example, a take-up vapor deposition machine is used, and the resin film coming off the unwinding roll in a vacuum chamber is placed in a vapor deposition chamber, where the vapor deposition source heated in a crucible is evaporated. Furthermore, if necessary, an inorganic vapor deposition layer is formed on the resin film on a cooled coating drum through a mask while oxygen or the like is sprayed from an oxygen outlet. The resin film with the inorganic vapor deposition layer formed thereon is then wound up on a take-up roll, thereby producing a resin film with an inorganic vapor deposition layer according to the present invention.

On the other hand, in the above-mentioned CVD method, a resin film is unwound from a winding roll placed in a vapor deposition chamber, and a mixed gas containing, for example, an organic silicon compound as a monomer gas, oxygen gas, an inert gas, etc., supplied from a vapor deposition raw material volatilization supply device is introduced onto the surface of the resin film, which is cooled in the vapor deposition chamber, and onto the circumferential surface of the electrode drum. This produces a resin film on which a vapor deposition layer of silicon oxide is formed by plasma.

In the above, the thickness of the inorganic 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-mentioned PVD method, the thickness of the inorganic 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 inorganic vapor deposition layer made of silicon oxide is preferably 30 Å to 3000 Å, more preferably 100 Å to 300 Å.
If the thickness of the inorganic vapor deposition layer exceeds the above range, cracks or the like may easily occur in the inorganic vapor deposition layer, which may reduce the barrier properties and increase the material cost, which is undesirable. If the thickness is less than the above range, it may be difficult to achieve sufficient oxygen barrier properties, which is undesirable.

Furthermore, the resin film with an inorganic vapor deposition layer has an acid permeability, measured in accordance with JIS K7126 at 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 range, the intrusion of oxygen from the outside of the package into the content-storing section inside the package can be sufficiently suppressed.
Furthermore, the resin film with an inorganic vapor deposition layer has a water vapor permeability, measured in accordance with JIS K7129 at 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 falls within the above range, the intrusion of water vapor from the outside of the package into the content-storing portion inside the package can be sufficiently suppressed.

When forming the inorganic vapor deposition layer, the surface of the resin film to be vapor-deposited can be cleaned by pretreatment such as _SiOx plasma, and polar groups, free radicals, etc. can be generated on the surface, thereby increasing the adhesion between the inorganic vapor deposition layer and the resin film.
Furthermore, when two or more inorganic vapor deposition layers are successively laminated using a plasma enhanced chemical vapor deposition apparatus comprising at least two or more film formation chambers, each layer can be deposited so as to have high gas barrier properties, thereby achieving gas barrier properties that are even higher than those of a single layer. Furthermore, by performing continuous deposition without exposure to the atmosphere, it is possible to prevent foreign matter, dust, etc., which can cause cracks, from being mixed between the inorganic vapor deposition layers, and the gas barrier properties are improved.
Furthermore, if the compositions of the vapor-deposited layers are different, the inorganic vapor-deposited layers are different discontinuous layers, and therefore 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 two or more kinds, and the oxidation-promoting catalyst contained may be one or two or more kinds.
The oxygen-absorbing adhesive composition may further contain a modifier, a diluting solvent, various additives, and the like, as required.

The oxygen-absorbing adhesive composition may be prepared by adding an oxygen-absorbing compound to an existing adhesive composition, or by using an oxygen-absorbing compound as a resin component.
Here, the existing oxygen-absorbing adhesive composition may be a one-component oxygen-absorbing adhesive composition or a two-component oxygen-absorbing adhesive composition.
The oxygen-absorbing adhesive composition and/or the above-mentioned existing adhesive composition may be curable or non-curable. If curable, it may be heat-curable, photo-curable, electron beam-curable, or the like.
The oxygen-absorbing compound may or may not react with components contained in existing adhesive compositions, or may react with itself.
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 that can react as a main 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-component urethane adhesive composition containing an isocyanate compound and a hydroxyl group-containing compound, in which 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 of the oxygen-absorbing adhesive composition 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 restrictions on the solids content in 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 this range, there is a risk that the oxygen absorption will be insufficient. The case of 100% by mass means that the oxygen-absorbing compound can be used as a resin component of the adhesive composition, and that it has sufficient adhesiveness by itself, has a functional group that can be cured by itself, or is used in combination with an oxygen-absorbing compound having a functional group that serves as a main component 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 may become unstable, and the oxygen absorption may be consumed before the microwave-safe oxygen-absorbing packaging container is produced, which may impair the effect of inhibiting deterioration due to oxygen after the microwave-safe oxygen-absorbing packaging container is produced.

[Oxygen-absorbing compound]
The oxygen-absorbing compound of the present invention has oxygen-absorbing properties, generates little odor, and can be used alone or mixed 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 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; 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 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 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 each be one or two or more types, and the number may be one or two or more. Furthermore, the number of organic groups 1 bonded to one unsaturated five-membered ring may be one or two 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 rings, organic groups 1, and organic groups 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 absorbability.
It is preferable that no electron-withdrawing group is bonded to the unsaturated five-membered ring, because the electron-withdrawing group bonded thereto reduces the electron density of the carbon-carbon double bond portion of the unsaturated five-membered ring, thereby reducing the reactivity with oxygen and 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.

The oxygen absorbing compound may or may not have a crosslinkable functional group.
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.
When 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 out 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.
When 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. Furthermore, the number of types of crosslinkable functional groups 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 lower than the above range, precipitation is likely to occur when mixed with a resin or resin composition. If the number-average molecular weight is higher than the above range, the viscosity of the mixture increases when mixed with a resin or resin composition, which often requires the addition of a large amount of diluent solvent, making it difficult to obtain a thick film or layer and reducing coatability.

In addition, the oxygen absorption activity of the oxygen-absorbing compound of the present invention can be accelerated by heating or the addition of 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 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 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 unsaturated five-membered rings 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, and it is difficult to obtain an oxygen-absorbing compound with a higher concentration than the above range, which tends to result in a poor balance between various physical properties.

(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 preferred, and one which, together with the unsaturated five-membered ring, constitutes an aliphatic bicyclic alkylene group is more preferred.
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 preferred.

(Electron-withdrawing organic group)
Specific examples of the electron-withdrawing group include a phenyl group, a phenylene group, a carbonyl group, and a halogen atom.
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, which reduces the reactivity with oxygen and results in 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 that substitutes the active hydrogen of the 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 part from which organic group 2 is derived, and the active hydrogen is substituted by organic group 2, resulting in bonding via a urethane group.
By bonding the organic group 2, the oxygen-absorbing compound can have two or more unsaturated five-membered rings in one molecule, and further, when mixed with a resin or a resin composition to prepare a mixture, the compatibility, dispersibility, and reactivity can be improved.Furthermore, the mixture and 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 moiety derived from an isocyanate compound and/or a hydroxyl group-containing compound. Here, the structural moiety derived from an isocyanate compound and/or a hydroxyl group-containing compound also includes a structural moiety 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, diphenyl ether diisocyanate, hydrogenated diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, and their trimethylolpropane adducts, biuret derivatives, allophanate derivatives, isocyanurate derivatives (trimers), and various derivatives thereof. Among these, biuret derivatives of toluene diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate are preferred.
In the present invention, one or more compounds selected from the group consisting of these isocyanate compounds can be used as the origin of the structural moiety of the monovalent and/or divalent or higher hydrocarbon group. When two or more compounds are used, two compounds may be used in the same molecule of the oxygen-absorbing compound, or molecules of the oxygen-absorbing compound having different compounds may be mixed.

The number average molecular weight of the isocyanate compound is preferably 100 to 10,000, more preferably 160 to
A number-average molecular weight of 5000 is more preferable. If the number-average molecular weight is smaller than the above range, precipitation is likely to occur when mixed with a resin or a resin composition. If the number-average molecular weight is larger than the above range, the viscosity of the mixture increases when mixed with a resin or a resin composition, which often requires the inclusion of a large amount of diluent solvent, making it difficult to obtain a thick film or layer and resulting in poor coating suitability.

(Hydroxy 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)acrylate 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 terminal hydroxyl group are preferred because they are more readily available, but they do not necessarily have to be at the terminal.
In the present invention, one or more 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 containing 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, precipitation is likely to occur when mixed with a resin or resin composition. If the number-average molecular weight is larger than the above range, the viscosity of the mixture increases when mixed with a resin or resin composition, which often requires the inclusion of a large amount of diluent solvent, making it difficult to obtain a thick film or layer and reducing coatability.

Polyhydric alcohols Polyhydric alcohols are monomers having two or more hydroxyl groups.
Specific examples of polyhydric alcohols include diols such as ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 1,6-hexanediol, cyclohexanedimethanol, 1,8-octanediol, 1,9-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, as well as 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 whose main skeleton 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, and ethylene-propylene copolymer, and which also have a hydroxyl group.
Among these, those having an ethylene-vinyl acetate copolymer or 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 hydroxyl groups.
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 of various polycarboxylic acids or derivatives thereof with 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 containing two or more polyhydric alcohols and two or more polycarboxylic 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 moiety in the main skeleton, and this polyol-derived moiety may be derived from the above-mentioned polyhydric alcohols, polyolefin polyol, polyether polyol, polyester polyol, or the like.
Among these, polycarbonate polyols containing two or more polyhydric alcohols in combination are preferred in order to reduce crystallinity.

Poly(meth)acrylic acid ester polyol Poly(meth)acrylic acid ester polyol is a (meth)acrylic acid ester (co)polymer having two or more hydroxyl groups.
Poly(meth)acrylic acid ester polyols 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 that does not have a hydroxyl group.
The diol used in synthesizing the (meth)acrylic acid ester having a hydroxyl group may be the above-mentioned diols, polyolefin polyol, polyether polyol, or the like.
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 between an aromatic hydroxyl group and an epoxy group.
Phenoxy resins obtained by reacting bisphenols with diglycidyl etherified bisphenols are readily available and are common.
Examples of polyhydric phenol compounds include bisphenol A and bisphenol F, and examples of polyepoxy compounds 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 diisocyanate compounds are preferred.

(Specific Examples of Oxygen-Absorbing Compounds)
Specific examples of oxygen-absorbing compounds 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.

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, thereby substituting the active hydrogen of the hydroxyl group and bonding a number of 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 members selected from the group consisting of polyhydric alcohols, polyolefin polyols, polyether polyols, polyester polyols, polycarbonate polyols, poly(meth)acrylate polyols, phenoxy resins, and urethane chain-extended polyols thereof.)

The oxygen-absorbing compound represented by formula (5) is an oxygen-absorbing compound in which a=2 in formula (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 includes a structural part 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 and containing 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)acrylate polyols, phenoxy resins, and urethane chain-extended polyols thereof.)

The oxygen-absorbing compound represented by formula (3) 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 moiety formed by the reaction of the two, and contains hydroxyl groups as residual excess hydroxyl groups or as a result of chemical modification.
(In the formula, b and c are each 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 members selected from the group consisting of polyhydric alcohols, polyolefin polyols, polyether polyols, polyester polyols, polycarbonate polyols, poly(meth)acrylate polyols, phenoxy resins, and urethane chain-extended polyols thereof.)

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 moiety formed by the reaction of the two, and contains an isocyanate group as a result of residual excess isocyanate groups or chemical modification.
(In the formula, d and e are each a number of 1 or more, and ^R3 is an organic group having 1 or more carbon atoms, which contains at least an alkylene and/or phenylene structure, and which may further contain a structure derived from one or more members selected from the group consisting of polyhydric alcohols, polyolefin polyols, polyether polyols, polyester polyols, polycarbonate polyols, poly(meth)acrylate 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 oxidation-promoting catalysts 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.
The transition metal is preferably cobalt, manganese, iron, nickel, copper, etc., and the anion or ligand is preferably anion or ligand formed from stearic acid, naphthenic acid, octylic acid, acetylacetonate, etc.
The oxidation-promoting catalyst may be a metal soap formed by combining a cation of one or more transition metals selected from the group consisting of the above-mentioned transition metals with an anion of one or more fatty acids selected from the group consisting of the above-mentioned long-chain fatty acids. Specific examples of the compound include cobalt octylate, cobalt(II) acetylacetonate, cobalt(III) acetylacetonate, manganese(III) acetylacetonate, and iron(III) acetylacetonate.

[Modifier]
The modifying agent 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, adjust the content of the oxygen-absorbing compound in the oxygen-absorbing adhesive composition, and 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 NCO/OH equivalent ratio 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 oxygen-absorbing adhesive composition may not cure sufficiently, and sufficient lamination strength (adhesion 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 compounds for use as modifiers)
The isocyanate compound used as the modifier can be the same 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. Furthermore, in order to ensure that the oxygen-absorbing adhesive composition cures, it is preferable for the compound to have two or more isocyanate groups per molecule. However, an isocyanate compound having one isocyanate group per molecule can also be used in combination, as long as the sufficient effect of the oxygen-absorbing adhesive composition is not impaired.
As the isocyanate compound having two or more isocyanate groups in one molecule, a biuret form of hexamethylene diisocyanate is particularly preferred.

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

(Hydroxyl-containing compounds for use as modifiers)
The hydroxyl group-containing compound used as the modifier can be the same hydroxyl group-containing compound used in the synthesis of the oxygen-absorbing compound, and any of aromatic hydroxyl group-containing compounds, aliphatic hydroxyl group-containing compounds, and urethane chain-extended polyols thereof can be used. Furthermore, in order to ensure that the oxygen-absorbing adhesive composition cures, compounds having two or more hydroxyl groups per molecule are preferred. However, a hydroxyl group-containing compound having one hydroxyl group per molecule can also be used in combination, as long as it does not impair 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 preferred.

[Various additives]
The oxygen-absorbing adhesive composition may contain various additives as needed.
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, adhesion aids, tackifiers, leveling agents, ultraviolet absorbers, and defoamers may also be added.

(Curing accelerator)
The curing accelerator can be any accelerator that accelerates the curing reaction of the oxygen-absorbing adhesive composition without any particular limitations.
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, and one or more types selected from the group consisting of these can be used.

(Cure adjuster)
When the pot life of an 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 selected from the group consisting of these can be used.
The amount of reaction modifier added is preferably 200 ppm to 400 ppm 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 will be inhibited.

(antioxidant)
The oxygen-absorbing adhesive composition may contain an antioxidant to suppress deterioration of oxygen absorption properties during storage or use of the oxygen-absorbing adhesive composition, and also 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 antioxidants include phenol-based, lactone-based, thioether-based, gallic acid-based, ascorbic acid, erythorbic acid, catechin, dibutylhydroxytoluene, tocopherol, citric acid, butylhydroxyanisole, phosphite ester, hindered amine, and aromatic amine-based antioxidants, and one or more selected from the group consisting of these can be used.
Furthermore, when it is assumed that heat or light is used as a trigger for the development of oxygen absorbing properties, it is preferable to use an antioxidant with low heat resistance and light resistance, such as ascorbic acid or tocopherol, and it is not preferable to use an antioxidant with high heat resistance and light resistance, such as a phenolic antioxidant.
The amount of 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, the oxygen-absorbing property may be reduced.

(Adhesion aid)
As an adhesion aid for improving 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, and one or more selected from the group consisting of these may be used.

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

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

(Antifoaming agent)
The antifoaming agent may be a surfactant, polyether-modified silicone oil, or the like, and one or more 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 constituent components, such as the oxygen-absorbing compound, the oxidation-promoting catalyst, and, if necessary, a modifier, a 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, a modifier, a 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 methods and mixing orders used in preparing general adhesive compositions can be applied.
Specific mixing methods include dissolving the components in a solvent and mixing them together, and melt-kneading. In this case, it is preferable to adjust the heating temperature to improve 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 general adhesive method can be used.
For example, a non-solvent lamination method in which the coating is heated to obtain an appropriate viscosity, or a dry lamination method in which a diluting solvent or other compounded adhesive is added to adjust the coating viscosity to an appropriate level, can be used.
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, sufficient oxygen absorption may not be obtained, and if the coating amount is more than the above range, the oxygen absorption does not change significantly, leading to cost disadvantages, and therefore is not preferred.

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

<About objects that can be glued>
There are no particular limitations on the objects to which the oxygen-absorbing adhesive composition can be bonded, and it can be bonded to, for example, resin molded products, resin films, paper, inorganic vapor-deposited film surfaces, and inorganic oxide vapor-deposited film surfaces.

Specific examples of resins for the resin film include polyester resins such as polyethylene terephthalate (PET), polyamide resins such as various nylons, polyethylene resins, polypropylene resins, cyclic polyolefin resins, polystyrene resins, polyolefin resins such as acrylonitrile-styrene copolymers (AS resins), acrylonitrile-butadiene-styrene copolymers (ABS resins), and 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 paper 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 in the inorganic vapor deposition layer 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.

<Shielding resin layer>
The shielding resin layer is a resin layer for preventing the migration of various additives, particularly antioxidants, from the sealant layer to the oxygen-absorbing adhesive layer, and may be composed of one layer or two or more layers.
The resin contained in the shielding resin layer is not particularly limited as long as it can block the migration of various additives, particularly antioxidants. Specific examples include polyester-based resins, nylon-based resins, polyolefin-based resins, etc.
Among the above, polyester resins and nylon resins are preferred because they are excellent in flexibility, puncture resistance, pinhole resistance, and the like.

The shielding resin layer may be formed by adhering a pre-prepared resin film for the shielding resin layer via an adhesive or the like, or by melt extrusion in which a molten resin composition is laminated onto another layer.
The resin film may be produced by melt-extruding one or more resin compositions and forming them into a film by an inflation method, or by extrusion using a T-die or the like, by melt-extruding onto a roll and constricting the extrusion. 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 shielding resin layer by melt extrusion, the resin composition is melted, (co)extruded, and poured onto the layer to be laminated, and the shielding 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, it is possible to prepare a single shielding resin layer or multiple shielding resin layers using resin compositions of the same or different compositions.

<Sealant layer>
The sealant layer is heat-sealed when the package is produced, and therefore preferably contains a heat-sealable resin.
Since the package is exposed to high temperatures during retort treatment, it is preferable that the sealant layer contains an antioxidant to improve heat resistance and resistance to oxidation degradation.
The content of the antioxidant in the sealant layer is preferably 0.01% by mass or more and 1% by mass or less. If the content is less than this range, the antioxidant effect is likely to be insufficient, and if the content is more than this range, the improvement in the antioxidant effect will plateau and the antioxidant may easily reach the oxygen-absorbing adhesive layer, thereby inhibiting oxygen absorption.
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.
The thickness of the sealant layer is preferably 10 μm to 200 μm, more preferably 30 μm to 100 μm.

The sealant layer may also contain any additives other than antioxidants, as long as they do not significantly impair the effects of the present invention. Examples of additives include various resin additives commonly used to improve the moldability and productivity of resin films and to adjust various physical properties, such as antiblocking agents, slip agents, pigments, flow control agents, flame retardants, fillers, UV absorbers, and surfactants.

[Heat-sealable resin]
Generally, the heat-sealable resin may be a polyolefin resin, an acid-modified polyolefin resin obtained by graft polymerization or copolymerization of a polyolefin resin with an unsaturated carboxylic acid or an anhydride thereof, such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, or itaconic acid, a polyvinyl acetate resin, a poly(meth)acrylic resin, a polyvinyl chloride resin, or the like. These resins may be used alone or in combination.
In the case of a packaging material for a microwave-compatible packaging container, in order to withstand microwave processing, a microwave-compatible heat-sealable resin of a high grade having a high softening point, heat resistance, resistance to oxidation and deterioration may be used, or an antioxidant or the like may be contained to enhance the heat resistance and resistance to oxidation and deterioration.
Here, the antioxidant suppresses oxidation of the heat-sealable resin by eliminating radicals that are generated over time or when heated to form the sealant layer or the resin film for the sealant layer.
For example, polypropylene is very susceptible to oxidation and deterioration, so it is difficult to use it without adding an antioxidant, and it also has the drawback of being poor in durability.
Polyethylene is relatively easy to use without adding antioxidants because it is not easily degraded by oxidation, but because it has low heat resistance, it must be made highly heat resistant through a special compounding process.
In the present invention, from the viewpoint of the balance between heat sealability, heat resistance, and resistance to oxidation and deterioration, among the above, microwave-compatible polyolefin-based resins having a softening point of 120°C or higher and 170°C or lower are preferred, and among microwave-compatible polyolefin-based resins, microwave-compatible polypropylene-based resins are more preferred.
It is further preferred to use a microwave-safe polypropylene resin together with an antioxidant.
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 resin and an antioxidant.

(Polyolefin resin)
Specific examples of polyolefin resins that are heat-sealable 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, ethylene-acrylic acid copolymers, ethylene-methacrylic acid copolymers, and cyclic olefin (co)polymers such as polynorbornene. The copolymers may be random or block copolymers.

Polyolefin resins are classified into 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 "polyolefin resin" is used as a general term for various types of polyethylene, and polyethylene resins are 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, and polyhexene-based resins, respectively.
Common polymerization methods include, for example, a high-pressure method for low-density polyethylene, and a low-pressure polymerization method (gas phase polymerization using a Ziegler-Natta catalyst or liquid phase polymerization using a metallocene catalyst), a slurry method, a solution method, a gas phase polymerization method, etc. for linear low-density polyethylene.

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

<Method for forming sealant layer>
The method for forming the sealant layer is not particularly limited, and any conventionally known method for laminating sealant layers can be applied.
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 the other layers constituting the laminate via an adhesive, etc. The sealant film may be prepared by melt-extruding one or more resin compositions and forming them into a film by an inflation method, or by extrusion using a T-die or the like, by melt-extruding the composition onto a roll and constricting it into a film.
Here, it is preferable to subject one side of the produced sealant film to a corona treatment, and then to adhere and laminate the film with the corona-treated side facing the side to be laminated.
Alternatively, the resin composition for forming the sealant layer may be melted, melt (co)extruded, and poured onto the layer to be laminated, and a sealant layer consisting of one or more layers may be laminated onto the other layers that make up the laminate by an extrusion method using a T-die molding method using a feed block method or a multi-manifold method.
In either method, a multi-layer sealant film can be produced by co-melt extrusion using resin compositions of the same or different compositions.

<General-purpose adhesive layer>
A general-purpose adhesive layer or anchor coat layer may be included between each layer constituting the oxygen-absorbing laminate for a microwave-safe packaging container.
For example, a sealant film for the sealant layer can be adhered via a general-purpose adhesive layer or anchor coat layer to form the sealant layer.
The general-purpose adhesive layer may be, for example, a layer (extruded resin layer) formed by a (co)extrusion lamination method in which an adhesive resin composition is melt-extruded, a T-die (co)extrusion method, or the like, or may be a layer (dry laminate layer) formed by dry lamination using a dry laminate adhesive.
Examples of resins that can be contained 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 anhydrides such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, and itaconic acid, polyvinyl acetate resins, poly(meth)acrylic resins, polyvinyl chloride resins, and other resins. These resins can be used alone or in combination.

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 copolymers may be random or block copolymers.
Polyolefin resins are classified into 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 "polyolefin resin" is used as a general term for various types of polyethylene, and polyethylene resins are 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, and polyhexene-based resins, respectively.

The general-purpose adhesive layer may contain additives such as antioxidants, ultraviolet absorbers, light stabilizers, antistatic agents, antiblocking agents, flame retardants, crosslinking agents, and colorants, as long as the additives do not impair the properties of the present invention.
The thickness of the general-purpose adhesive layer is not particularly limited, but is preferably 1 g/m or ^more and 20 g/m 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.
Furthermore, examples of adhesives that can be used for dry lamination that constitute the general-purpose 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.

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 resistance temperature of 135° C. or higher, such as a vinyl-modified resin, an epoxy resin, a urethane resin, a polyester resin, or polyethyleneimine.
Among the above, curable anchor coating agents are particularly preferred, which contain a polyacrylic or polymethacrylic resin (polyol) having two or more hydroxyl groups per molecule as the base agent and an isocyanate compound as the 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-shielding layer, and a reinforcing layer.

[Auxiliary Barrier Layer]
The auxiliary barrier layer is a layer made of a resin that enhances oxygen gas resistance and provides barrier properties against 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, and resins in which part of the ethylene component and/or terephthalate component is copolymerized or modified with other di- or higher polyhydric alcohol components or dicarboxylic acid components; 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 resins that have both aroma retention and barrier properties against oxygen gas or water vapor. Specifically, it is preferable to use resins 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 low adsorption of flavoring ingredients contained in the contents to be filled and packaged, has excellent aroma-retaining properties, and further has the property of not causing any strange taste or unpleasant odor.

[Light blocking layer]
The light-shielding layer is made of a light-shielding material and prevents ultraviolet light and/or visible light from reaching the contents, thereby preventing the contents from being altered by light.
The light-shielding layer can be formed using white ink mainly composed of titanium oxide or the like, black ink mainly composed of carbon black or the like, gray ink mainly composed of aluminum paste, colorant-colored resin film made light-shielding by adding pigments or dyes or the like, metal foil, metal vapor deposition film, or the like.
As described above, when a metal foil such as an aluminum foil is used as the barrier layer, the barrier layer can also serve as a light-shielding layer.
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.
In the case of aluminum foil, the thickness is preferably 5 μm to 30 μm, in the case of a metal vapor deposition film, the thickness is preferably 50 Å to 3000 Å, more preferably 100 Å to 1000 Å, and in the case of a colorant-colored resin film, the thickness is preferably 5 μm to 300 μm, more preferably 10 μm to 100 μm.

[Reinforcing layer]
The reinforcing layer is a layer that imparts mechanical strength, deformation resistance, drop impact resistance, pinhole resistance, heat resistance, airtightness, quality maintenance, workability, sanitation, and the like to the laminate.
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-based resin, polyvinyl chloride-based resin, polyvinyl acetate-based resin, polyvinylidene chloride-based resin, vinyl chloride-vinylidene chloride copolymer, poly(meth)acrylic resin, polyacrylonitrile-based resin, polystyrene-based resin, acrylonitrile-styrene copolymer (AS-based resin), acrylonitrile-butadiene-styrene copolymer (ABS-based resin), polyester-based resin, polyamide-based resin, polycarbonate-based resin, polyvinyl alcohol-based resin, saponified ethylene-vinyl acetate copolymer, fluorine-based resin, diene-based resin, polyacetal-based resin, polyurethane-based resin, cellulose, nitrocellulose, and other known resins.
The resin film may be unstretched or uniaxially or biaxially stretched.
The thickness of the reinforcing layer is not particularly limited, but can be selected from the range of several μm to about 300 μm.

<Method for producing oxygen-absorbing laminate for microwave-safe packaging container>
A method for producing an oxygen absorbing laminate for a microwaveable packaging container using the above-mentioned materials will be described. The production method shown below is an example and does not limit the present invention.
The lamination of each layer constituting the oxygen-absorbing laminate for a microwave-safe packaging container can be carried out by any lamination method 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 laminate for a microwave-safe packaging container of the present invention can also be subjected to secondary processing in order to impart 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, adhesive, printing, metallizing (plating, etc.), mechanical processing, surface treatment (antistatic treatment, corona discharge treatment, plasma treatment, photochromism treatment, physical vapor deposition, chemical vapor deposition, coating, etc.), etc. The laminate of the present invention can also be subjected to lamination (dry lamination or extrusion lamination), bag making, and other post-processing.

If necessary, the surfaces of each layer can be pretreated, for example, by corona treatment or ozone treatment, during the lamination process. Additionally, anchor coating agents such as isocyanate (urethane), polyethyleneimine, polybutadiene, and organic titanium anchor coating agents, as well as laminating adhesives such as polyurethane, polyacrylic, polyester, epoxy, polyvinyl acetate, cellulose, and others, can be used.

As long as the substrate layer, inorganic oxygen barrier layer, oxygen-absorbing adhesive layer, shielding resin layer, and sealant layer are laminated in this order, the order in which each layer is formed and laminated may be arbitrary.
For example, an example will be described in which an oxygen-absorbing laminate for a microwave-safe packaging container is produced, having a layer structure of substrate layer/inorganic oxygen barrier layer/oxygen-absorbing adhesive layer/shielding resin layer/sealant layer.
For example, first, an oxygen-absorbing adhesive composition is applied to the inorganic vapor deposition surface of a resin film with a one-sided inorganic vapor deposition layer, which is a film having a base layer and an inorganic oxygen barrier layer, and dried to form an oxygen-absorbing adhesive layer, and then a resin film for the shielding resin layer is adhered and laminated.
Next, a general-purpose adhesive for dry lamination is applied to the surface of the shielding resin layer, dried, and a sealant film for the sealant layer is adhered and laminated.
Then, an aging treatment is performed as necessary.
In this manner, an oxygen-absorbing laminate for a microwave-safe packaging container can be obtained.

<<Oxygen-absorbing packaging material for microwave-safe packaging containers>>
The oxygen-absorbing packaging material for a microwave-safe packaging container is a packaging material produced from the oxygen-absorbing laminate for a microwave-safe packaging container of the present invention.
The oxygen-absorbing packaging material for a microwave-safe packaging container may have the same layer structure as the oxygen-absorbing laminate for a microwave-safe packaging container, and may further include layers having various functions, as necessary.

<<Microwave-safe oxygen-absorbing packaging container>>
The microwave-safe oxygen-absorbing packaging container is a microwave-safe packaging container made from the oxygen-absorbing packaging material for microwave-safe packaging containers of the present invention.
Specific examples of microwave-compatible oxygen-absorbing packaging containers include microwave-compatible oxygen-absorbing pouches, microwave-compatible oxygen-absorbing containers consisting of a microwave-compatible oxygen-absorbing lid part and a microwave-compatible oxygen-absorbing bottom part, molded containers, squeeze containers for ham, etc. In addition, added value can be added by various shape designs and printed decorations.
In addition, oxygen-absorbing packaging containers made using conventional iron powder-based oxygen-absorbing films are darkly colored, making it impossible to visually check the contents, making it impossible to inspect the contents using a metal detector or the like, making it impossible to heat in a microwave oven, and raising concerns about rust due to moisture.In contrast, the microwave-compatible oxygen-absorbing packaging container of the present invention does not contain an iron powder-based oxygen absorber, and therefore the pouch is colorless and/or transparent, the contents can be visually checked, 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 concern about rust due to moisture.

Microwave-safe oxygen-absorbing pouch
The microwave-safe oxygen-absorbing pouch is one embodiment of the microwave-safe oxygen-absorbing packaging container of the present invention, and has a bag-like shape. It may be a packaging bag of various shapes. In addition, added value can be added by various shape designs and printed decorations.
Pouches can be made using less material than bottles, making them effective in saving resources.
Specific examples of the shape of the microwave-compatible oxygen-absorbing pouch include a basic, flat, planar pouch, a gusseted 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 small liquid pouches, a pouch for bag-in-box use, a pouch for infusion bags, a pouch for stick packaging, and a pouch with a spout in the center or at the upper corner of the pouch. The addition of a zipper or spout can increase convenience in putting contents in and out and in storing the pouch, but it is preferable that the pouch have a steam mechanism (46) as shown in FIG. 4.
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. 2. It may have one or two notches (13a, 13b).

[Method for producing a microwave-safe oxygen-absorbing pouch]
Microwave-compatible oxygen-absorbing pouches can be produced in various shapes, for example, by folding an oxygen-absorbing packaging material for a microwave-compatible packaging container in half, stacking it to encase the contents, or stacking two sheets of oxygen-absorbing packaging material for a microwave-compatible packaging container with the sealant layer surfaces facing each other, and then heat-sealing the peripheral edges in various ways.
Examples of heat seal forms include side seal type, two-sided seal type, three-sided seal type, four-sided seal type, envelope seal type, palm seal type (pillow seal type), pleated seal type, flat bottom seal type, square bottom seal type, and gusset type.
Examples of heat sealing methods include bar sealing, rotary roll sealing, belt sealing, impulse sealing, high frequency sealing, ultrasonic sealing, and flame sealing.
The microwave-safe 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-safe oxygen-absorbing packaging container of the present invention may be, for example, a microwave-safe packaging container made by combining a microwave-safe oxygen-absorbing lid part and a microwave-safe oxygen-absorbing bottom part having a recess, as shown in Figure 3.
Hereinafter, the oxygen-absorbing retort packaging container will be abbreviated as the container, the oxygen-absorbing retort lid part will be abbreviated as the lid part, and the oxygen-absorbing retort bottom part will be abbreviated as the bottom part.
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 together at the fringe portions so as to face each other.

Contents can be placed in the recess within the container, and this placement is done before the lid and bottom components are heat-sealed together. After the contents are placed inside, the flange of the bottom component is bonded to the film-like lid component by heat sealing or adhesive, protecting the contents with an airtight seal. The contents can then be removed by peeling off the lid component.

[Microwave-safe oxygen-absorbing lid parts]
The oxygen-absorbing microwave-safe closure part of the present invention is a closure part for a microwave-safe packaging container made from the oxygen-absorbing packaging material for a microwave-safe 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 base part of the present invention is a base part made from the oxygen-absorbing packaging material for a microwave-safe packaging container of the present invention. In addition, added value can be added by various shape designs and printing decorations.
The bottom 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 comprising a lid component and a bottom component>>
The microwave-safe oxygen-absorbing packaging container of the present invention, which comprises a lid part and a bottom part, can be produced, for example, by the following production method.
The following examples are merely examples of methods for producing a microwave-safe oxygen-absorbing packaging container, and the present invention is not limited thereto.
To manufacture the container shown in FIG. 3, first, a tray-shaped bottom part shown in FIG. 3 is prepared.
Then, the lid part is 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 on two or more bottom parts and heat-sealed, and the two or more bottom parts may be cut separately or connected.
In the above, the heat sealing can be carried out by a known method such as bar sealing, rotary roll sealing, belt sealing, impulse sealing, high frequency sealing, ultrasonic sealing, or flame sealing.

When one lid part is placed on one bottom part, the lid part may be shaped to match the outer periphery of the flange portion of the bottom part, or slightly larger than the outer periphery, or may partially protrude beyond the outer periphery.
Furthermore, when one lid part is placed on 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 part, 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 bottom 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 heat sealing and then perform the sheet sealing.

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

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

<Raw materials>
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: 1,000.
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: 1,200. 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-promoting catalyst solution 1: Octope AE, manufactured by Hope Pharmaceutical Co., Ltd. A 4% ethyl acetate solution of cobalt octylate, an oxidation-promoting catalyst.
Pro-oxidation catalyst solution 2: Acetop Mn(III) manufactured by Hope Pharmaceutical Co., Ltd. A 10% ethyl acetate solution of manganese acetylacetonate (III), a pro-oxidation catalyst.

[General-purpose adhesive]
DL Adhesive 1: Ru-004/H-1, a two-component curing polyester polyurethane general-purpose adhesive for dry lamination, manufactured by Rock Paint Co., Ltd.

[Film for base layer]
Transparent vapor-deposited PET film 1: IB-PET manufactured by Dai Nippon Printing Co., Ltd. One-sided transparent alumina vapor-deposited PET film. 12 μm thick. The alumina vapor-deposited layer functions as an inorganic oxygen barrier layer.

[Film for shielding resin layer]
PET film 1: E5202, a biaxially oriented PET film manufactured by Toyobo Co., Ltd., corona treated on both sides, 12 μm thick. Nylon film 1: ONBC, a biaxially oriented nylon film manufactured by Unitika Ltd., 15 μm thick.

[Sealant layer film]
CPP film 1: Unstretched CPP film, ZK99S, manufactured by Toray Advanced Film Co., Ltd., 60 μm thick. Contains microwave-safe polypropylene and antioxidants.

<Preparation of raw material solution>
(Synthesis of Polyol 1 and Preparation of Polyol Solution 1)
The following raw materials were placed in 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 solid content of the reaction liquid reached 15 mgKOH/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 and the reaction was allowed to continue.
When the acid value of the solid content of the reaction liquid became 3 mgKOH/g or less, the reaction was terminated and the reaction 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 1 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 the isocyanate groups had completely disappeared by infrared absorption spectroscopy, the synthesis was terminated and the mixture was cooled to obtain Polyol 2.
The resulting urethane chain-extended polyol, Polyol 2, had a number average molecular weight of 2,000.
Next, polyol 2 was dissolved in ethyl acetate to prepare a polyol solution 2 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.
Biuret form of hexamethylene diisocyanate 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 while stirring.
Oxygen-absorbing compound 1 100.0 parts by mass Isophorone diisocyanate 74.0 parts by mass After confirming that the absorption of the isocyanate group had completely disappeared in the infrared absorption spectrum, the synthesis was terminated and the mixture was cooled to obtain oxygen-absorbing compound 2.
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 while stirring.
Oxygen-absorbing compound 1 100.0 parts by mass Polyisocyanate solution 1 212.5 parts by mass The synthesis was terminated upon confirming that the content of NCO groups in the solid content of the reaction liquid, as determined by the amine equivalent method, had reached approximately 0.64% by mass, and the reaction 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 while 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 in the infrared absorption spectrum, the synthesis was terminated, and the mixture was cooled and the solvent was removed, thereby obtaining 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 preparation of 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 mixture was reacted at an internal temperature of 80 to 90° C. for 6 hours 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 in the infrared absorption spectrum, 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 to synthesize oxygen-absorbing compounds 2 to 6 are summarized 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 to homogenize, to obtain an oxygen-absorbing adhesive composition A1, which was then subjected to various evaluations.
Oxygen absorbing compound solution 2 100 parts by mass Polyol solution 1 100 parts by mass Polyisocyanate solution 1 10 parts by mass Oxidation promoting catalyst solution 1 1 part by mass Ethyl acetate 140 parts by mass

(Preparation of oxygen-absorbing adhesive compositions A2 to A9, B1 and 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>
Using each of the oxygen-absorbing adhesive compositions obtained above, a test laminate film was produced, 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. After that, an LLDPE film 1 was laminated to the PET film 1, and the film was 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 heat-sealed on three sides 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 15 mm wide strip test piece 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 rate of 50 mm/min.

[Odor]
After measuring the oxygen absorbency, 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 Laminate>
[Example 1]
An oxygen-absorbing adhesive A1 was applied to the vapor-deposited surface of the transparent vapor-deposited PET film 1 so that the dry coating amount was 3 g/ ^m2 and dried, and then the PET film 1 was bonded to the vapor-deposited surface by dry lamination to obtain a laminated film.
Next, DL adhesive 1 was applied to one surface of the PET film of the obtained laminated film so that the dry coating amount was 3 g/ ^m² and dried, and then CPP film 1 was attached 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: transparent vapor-deposited PET film 1 (12 μm thick) [PET film layer/transparent alumina vapor-deposited layer]/oxygen-absorbing adhesive composition A1 (3 g/m ² )/PET film 1 (12 μm thick)/DL adhesive 1 (3 g/m ² )/CPP film 1 (60 μm thick)

[Example 2]
An oxygen-absorbing laminate for a microwave-safe packaging container was obtained in the same manner as in Example 1, except that PET film 1 was replaced with Nylon Film 1, and evaluation was carried out in the same manner.

[Comparative Example 1]
DL adhesive 1 was applied to the vapor-deposited surface of transparent vapor-deposited PET film 1 so that the dry coating amount was 3 g/m ² and dried, and then nylon film 1 was laminated thereon by dry lamination to obtain a laminated film.
Next, oxygen-absorbing adhesive composition A1 was applied to the PET film surface of the obtained laminated film so that the dry coating amount was 3 g/ ^m2 and dried, and then CPP film 1 was attached using the dry lamination method and aged at 40°C for 3 days to obtain a laminate with the following layer structure, which was evaluated in the same manner as in Example 1.
Layer structure: transparent vapor-deposited PET film 1 (12 μm thick) [PET film layer/transparent alumina vapor-deposited layer]/DL adhesive 1 (3 g/m ² )/nylon film 1 (15 μm thick)/oxygen-absorbing adhesive (3 g/m ² )/CPP film 1 (60 μm thick)

<Evaluation method>
[Laminate transparency]
The transparency of the resulting laminate was judged visually.
○: Transparent ×: Opaque

[Heat sealability]
Two 100 mm x 100 mm laminates were cut out from the obtained laminate, 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.), a 10 mm x 100 mm area was heat-sealed under the following conditions, and a test piece for peel strength was prepared in which the edges were not heat-sealed or bonded, and were divided into two.
This test piece was cut into a 15 mm wide strip, and each bifurcated end was attached to a tensile tester to measure the peel strength (N/15 mm) under the following conditions, and the result was judged as pass/fail according to the following pass/fail criteria.
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 15 mm x 100 mm strip test piece was cut out from the obtained laminate, and the interlayer adhesive strength sandwiching the oxygen-absorbing adhesive layer was measured using a tensile tester at a pulling rate of 50 mm/min.
Pass/fail criteria: ◯: 3N/15mm or more, passed.
×: Less than 3N/15mm, unacceptable.

[Dissolved oxygen content]
A pouch with an inner dimension of 110 mm x 150 mm was prepared from the obtained laminate, 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 microwave treatment (600 W, 2 minutes) was measured using a non-destructive oxygen concentration meter (non-destructive oxygen concentration meter manufactured by Presence: FIBOX3 OXYGEN METER).

[Microwave resistance]
A pouch with an inner dimension of 110 mm x 150 mm was prepared from the obtained laminate, 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 delamination of the pouch was detected visually. The meanings of the descriptions in the table are as follows.
○: No delamination ×: Delamination

[Sensory evaluation of odor and taste]
After measuring the amount of dissolved oxygen as described above, the drinking water inside the pouch was subjected to a sensory evaluation of the taste and odor according to the following evaluation criteria.
Evaluation criteria:
0: Tasteless and odorless 1: Faint odor 2: Weak odor 3: Medium odor 4: Strong odor

<Summary of results>
The oxygen-absorbing laminates for microwave-safe packaging containers of all Examples of the present invention exhibited better oxygen absorption than the laminate of Comparative Example 1, which did not have a shielding resin layer. They also exhibited an excellent balance of heat sealability, interlayer adhesion, oxygen absorption, microwave resistance, and low odor.

1 oxygen-absorbing laminate for microwave-safe packaging container 2 substrate layer 3 inorganic oxygen barrier layer 4 oxygen-absorbing adhesive layer 5 shielding resin layer 6 sealant layer

10 Microwave-safe oxygen-absorbing flat pouch 11a, 11b Wall film 12 Seal portion 13a, 13b Notch

20 Microwave-compatible oxygen-absorbing packaging container 21 Microwave-compatible oxygen-absorbing bottom part 22 Content-accommodating recess 23 Flange part 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 Opening notch 46 Steam mechanism 46a Unheat-sealed portion 46b Isolated heat-sealed portion

Claims (18)

An oxygen-absorbing laminate for a microwave-safe packaging container, comprising at least a substrate layer, an inorganic oxygen barrier layer, an oxygen-absorbing adhesive layer, a shielding resin layer, and a sealant layer in this order,
the inorganic oxygen barrier layer comprises a metal oxide;
the oxygen-absorbing adhesive layer is a layer formed from an oxygen-absorbing adhesive composition,
The oxygen-absorbing adhesive composition contains at least an oxygen-absorbing compound and an oxidation-promoting catalyst,
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,
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 an active hydrogen of an active hydrogen group on each of the five-membered rings or the organic group 1,
the shielding resin layer contains one or more resins selected from the group consisting of nylon-based resins, polyolefin-based resins, and polyester-based resins;
the sealant layer contains a polyolefin resin and an antioxidant,
The polyolefin resin has a softening point of 120°C or higher and 170°C or lower. The oxygen-absorbing laminate for a microwave-safe packaging container according to claim 1, characterized in that the unsaturated five-membered ring structure or the structure consisting of the unsaturated five-membered ring and organic group 1 is derived from one or more members selected from the group consisting of cyclopentadiene, dicyclopentadiene, norbornene, and derivatives thereof. The oxygen-absorbing laminate for a microwave-safe packaging container according to claim 1 or 2, wherein the organic group 2 includes a structural portion derived from an isocyanate compound or an isocyanate compound and a hydroxyl group-containing compound. The oxygen-absorbing laminate for a microwave-safe packaging container according to claim 3, wherein the isocyanate compound is one or more compounds selected from the group consisting of xylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, and derivatives thereof. The oxygen-absorbing laminate for a microwave-safe packaging container according to claim 3 or 4, characterized in that the hydroxyl group-containing compound is 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. The oxygen-absorbing laminate for a microwave-safe packaging container according to any one of claims 1 to 5, wherein the organic group 2 does not have a crosslinkable functional group. the organic group 2 has one or more crosslinkable functional groups,
The crosslinkable functional group is a hydroxyl group and/or an isocyanate group.
The oxygen-absorbing laminate for a microwave-safe packaging container according to any one of claims 1 to 5. The oxygen-absorbing laminate for a microwave-safe packaging container according to any one of claims 1 to 5, characterized in that the oxygen-absorbing compound contains one or more compounds selected from the group consisting of compounds represented by the following formulas (1) to (4):
(In the formula, a to e are each a number of 1 or more, and each of R ¹ , R ² , and R ³ is an organic group having 1 or more carbon atoms, containing at least an alkylene and/or phenylene structure, and may further contain a structure derived from one or more members selected from the group consisting of polyhydric alcohols, polyolefin polyols, polyether polyols, polyester polyols, polycarbonate polyols, poly(meth)acrylate polyols, phenoxy resins, and urethane chain-extended polyols thereof.) 6. The oxygen-absorbing laminate for a microwave-safe packaging container according to claim 1, wherein the oxygen-absorbing compound contains a compound represented by the following formula (5):
(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 and containing 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)acrylate polyols, phenoxy resins, and urethane chain-extended polyols thereof.) The oxygen-absorbing laminate for a microwave-safe packaging container according to any one of claims 1 to 9, wherein the oxidation-promoting catalyst is a peroxide or a compound containing a cation made of a transition metal. The oxygen-absorbing laminate for a microwave-safe packaging container according to any one of claims 1 to 10, characterized in that the compound containing a cation made of a transition metal is a metal soap made of a transition metal compound capable of releasing a cation or complex made of a transition metal, and an anion or ligand made of a fatty acid. The oxygen-absorbing adhesive composition further contains a modifier,
12. The oxygen-absorbing laminate for a microwave-safe packaging container according to claim 1, wherein the modifying agent contains an isocyanate compound and/or a hydroxyl group-containing compound. The oxygen-absorbing laminate for a microwave-safe packaging container according to claim 12, characterized in that the isocyanate compound is one or more compounds selected from the group consisting of xylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, and derivatives thereof. The oxygen-absorbing laminate for a microwave-safe packaging container according to claim 12 or 13, characterized in that the hydroxyl group-containing compound comprises one or more compounds selected from the group consisting of polyester polyols, poly(meth)acrylic acid ester polyols, polyalkylene ether diols, and urethane chain-extended polyols thereof. The total light transmittance is 80 or more,
The haze value is 40 or less,
The oxygen-absorbing laminate for a microwave-safe packaging container according to any one of claims 1 to 14, which is transparent. An oxygen-absorbing packaging material for microwave-safe packaging containers, characterized in that it is made using the oxygen-absorbing laminate for microwave-safe packaging containers described in any one of claims 1 to 15. A microwave-safe, oxygen-absorbing packaging container made using the oxygen-absorbing packaging material for microwave-safe packaging containers described in claim 16. A microwave-safe, oxygen-absorbing pouch made using the oxygen-absorbing packaging material for microwave-safe packaging containers described in claim 16.