JP7725849B2 - Highly heat-resistant, low-odor gas adsorption laminate - Google Patents

Description

The present invention relates to a highly heat-resistant, low-odor gas-adsorbing laminate that adsorbs gases generated by itself and gases from the space in contact with it, and releases only a small amount of gas even when heated, without causing any change in the odor or taste of the contents.

In recent years, packaging materials containing odor adsorbents that adsorb odors have been proposed to prevent contamination, deterioration, and changes in odor and taste of the contents of the package (Patent Document 1). In such packaging materials, odor adsorbents such as synthetic zeolite and activated carbon are kneaded into a resin material.
Packaging materials containing an odor adsorbent made by supporting a chemical adsorbent on an inorganic porous material are also known (Patent Document 2), but the main object of adsorption is only to adsorb odorous components having specific functional groups. In situations where the resin material is not selected appropriately, the amount of organic matter not having functional groups generated cannot be suppressed, and odorous components cannot be sufficiently adsorbed.
Furthermore, hygroscopic packaging materials that suppress the generation of unpleasant odors due to hydrolysis of the contents are also known (Patent Document 3), but although they are effective in suppressing odor generation, the generated odor components remain as they are, so a sufficient odor improvement effect was not obtained. Also, for applications used in high-temperature sterilization processes such as retort sterilization and high-temperature boiling, a lid material film having a functional resin layer containing an oxygen absorber and a gas adsorbent has been proposed to reduce residual odors in the package and improve odors (Patent Document 4), but it is unable to adsorb all of the resin decomposition components that are generated when the oxygen absorption properties are expressed, and furthermore, because it is a lid material film, an easy-peel layer is formed on the inner surface, making it unsuitable for general-purpose use.

Patent No. 2538487 JP 2014-233408 A JP 2006-327690 A Patent No. 5046098

The objective of the present invention is to provide a laminate that has high heat resistance capable of withstanding temperatures from boiling to semi-retort heating (90-110°C), emits little gas from itself, adsorbs gases from the outside that it comes into contact with, and suppresses changes in the taste and odor of the contents.

As a result of extensive investigations, the present inventors have found that the above-mentioned object can be achieved by a laminate having at least a gas barrier substrate layer and a sealant layer containing a specific highly heat-resistant, low-odor resin and a gas adsorbent.
That is, the present invention is characterized by the following points.
1. A highly heat-resistant, low-odor, gas-adsorbing laminate having a gas barrier substrate layer and a highly heat-resistant, low-odor, gas-adsorbing sealant layer,
The gas barrier substrate layer has a substrate layer made of a resin film and a gas barrier layer,
the gas barrier layer comprises one or a combination of two or more selected from the group consisting of a metal foil, a metal vapor-deposited film, and a metal oxide vapor-deposited film;
The high heat resistant, low odor gas adsorption sealant layer contains a high heat resistant, low odor resin having heat sealing properties and a gas adsorbent, and adsorbs gases generated from the high heat resistant, low odor gas adsorption sealant layer itself and gases from the outside of the high heat resistant, low odor gas adsorption sealant layer,
the gas is one or a combination of two or more selected from the group consisting of hydrocarbons, aldehydes, ketones, and carboxylic acids;
The density of the high heat resistance and low odor resin is 0.920 g/cm ^{or more} and 0.960 g/cm or ^less ,
The film made of the highly heat-resistant, low-odor resin has a concentration of elutable total organic carbon (TOC) of 1.5 ppm or more and 250 ppm or less, and is characterized in that it elutes when boiled at 90 to 110°C for 30 minutes and then left to stand at 35°C.
The highly heat-resistant, low-odor gas-adsorbing laminate.
2. 70% by mass or more and 100% by mass or less of the resin contained in the high heat resistant, low odor gas adsorption sealant layer is the high heat resistant, low odor resin,
The gas adsorbent is contained in a layer containing the gas adsorbent in an amount of 0.1 mass% or more and 30 mass% or less.
2. The highly heat-resistant, low-odor gas-adsorbing laminate according to 1 above.
3. The highly heat-resistant, low-odor gas adsorption laminate according to item 1 or 2 above, wherein the highly heat-resistant, low-odor resin is a polyethylene-based resin.
4. The highly heat-resistant, low-odor gas adsorption laminate according to any one of items 1 to 3 above, wherein the highly heat-resistant, low-odor resin is one or a combination of two or more selected from the group consisting of high-density polyethylene, medium-density polyethylene, low-density polyethylene, and linear low-density polyethylene.
5. The highly heat-resistant and low-odor gas adsorbent laminate according to any one of items 1 to 4 above, wherein the gas adsorbent comprises one or a combination of two or more selected from the group consisting of hydrophobic zeolite, molecular sieve, metal-organic framework (MOF), and activated carbon.
6. The high heat resistance, low odor gas adsorption sealant layer has a gas adsorption layer and a heat seal layer,
the gas adsorption layer is a layer containing the high heat-resistant, low odor resin and the gas adsorbent,
the heat seal layer contains the highly heat-resistant, low-odor resin and has heat sealability;
At least the outermost layer of the highly heat-resistant, low-odor, gas-adsorbing sealant layer is a heat seal layer,
The high heat resistant, low odor resin contained in the gas adsorption layer and the high heat resistant, low odor resin contained in the heat seal layer are the same or different.
6. A highly heat-resistant, low-odor gas-adsorbing laminate according to any one of items 1 to 5 above.
7. The heat shrinkage rate when boiled for 10 minutes to 60 minutes at a temperature of 90°C to 100°C is 0% to 10%.
It is characterized by the absence of orange peel-like changes on the surface.
7. A highly heat-resistant, low-odor gas-adsorbing laminate according to any one of items 1 to 6 above.
8. A highly heat-resistant, low-odor, gas-adsorbing packaging material with low gas release properties, produced using the highly heat-resistant, low-odor, gas-adsorbing laminate described in any one of items 1 to 7 above.
9. A highly heat-resistant, low-odor, gas-adsorbing packaging material for boiling sterilization or semi-retort sterilization, which is produced using the highly heat-resistant, low-odor, gas-adsorbing laminate according to any one of items 1 to 7 above.
10. A highly heat-resistant, low gas-releasing, gas-adsorbing package produced using the highly heat-resistant, low gas-releasing, gas-adsorbing packaging material according to 8 or 9 above.

According to the present invention, it is possible to obtain a laminate that has high heat resistance capable of withstanding temperatures (90 to 110°C) from boiling to semi-retort heating treatment, emits little gas from itself, adsorbs gases from the outside that come into contact with it, and suppresses changes in the odor and taste of the contents, as well as a packaging material and a package made using the laminate.

1 is a schematic cross-sectional view showing an example of the layer structure of the highly heat-resistant, low-odor gas-adsorbing laminate or highly heat-resistant, low-odor gas-adsorbing packaging material of the present invention. FIG. 2 is a schematic cross-sectional view showing another example of the layer structure of the highly heat-resistant, low-odor gas-adsorbing laminate or highly heat-resistant, low-odor gas-adsorbing packaging material of the present invention. FIG. 1 is a schematic cross-sectional view showing an example of the layer structure of a highly heat-resistant, low-odor gas-adsorbing sealant film that forms the sealant layer of the highly heat-resistant, low-odor gas-adsorbing laminate or highly heat-resistant, low-odor gas-adsorbing packaging material of the present invention. FIG. 1 is a schematic cross-sectional view showing another example of the layer structure of a highly heat-resistant, low-odor gas-adsorbing sealant film that forms the sealant layer of the highly heat-resistant, low-odor gas-adsorbing laminate or highly heat-resistant, low-odor gas-adsorbing packaging material of the present invention. This is a schematic cross-sectional view showing an example of another embodiment of a highly heat-resistant, low-odor gas-adsorbing sealant film that forms the sealant layer of the highly heat-resistant, low-odor gas-adsorbing laminate or highly heat-resistant, low-odor gas-adsorbing packaging material of the present invention, having a different layer structure.

In each drawing, the size and proportions of the components may be changed or exaggerated for ease of understanding. Also, for clarity, parts that are unnecessary for explanation or repeated reference numerals may be omitted.
Although not shown in the drawings, adhesive layers may be provided between the layers.
Furthermore, if necessary, in order to strengthen the adhesive strength (adhesion strength) between each layer, the laminated surfaces of each layer may be subjected in advance to physical surface treatments such as corona discharge treatment, ozone treatment, plasma treatment, glow discharge treatment, sandblasting treatment, etc., or chemical surface treatments such as oxidation treatment using chemicals.

The highly heat-resistant, low-odor gas-adsorbing laminate, the highly heat-resistant, low-odor gas-adsorbing packaging material, and the highly heat-resistant, low-odor gas-adsorbing packaging body of the present invention will be described in more detail below. Specific examples will be given, but the present invention is not limited thereto.
In the present invention, the terms film and sheet are used synonymously.

<High heat resistance, low odor gas adsorption laminate>
The highly heat-resistant, low-odor, gas-adsorbing laminate of the present invention is a laminate having a gas barrier substrate layer and a highly heat-resistant, low-odor, gas-adsorbing sealant layer, and has heat-sealing properties, low gas release properties, and the ability to adsorb gases, thereby suppressing changes in the odor and taste of the contents.
The gas barrier substrate layer is a layer that has gas barrier properties and rigidity as a substrate layer.
The high heat resistant, low odor gas adsorption sealant layer contains a high heat resistant, low odor resin with heat sealing properties and a gas adsorbent, and adsorbs gases generated from the high heat resistant, low odor gas adsorption sealant layer itself as well as gases from outside the high heat resistant, low odor gas adsorption sealant layer.
The highly heat-resistant, low-odor gas adsorption laminate of the present invention has high heat resistance that can withstand temperatures from boiling to semi-retort sterilization (90 to 110°C).

The highly heat-resistant, low odor gas adsorption laminate has excellent heat resistance in the above-mentioned applications, low gas release properties and excellent gas adsorption properties after high-temperature treatment, and can suppress changes in the taste and odor of the contents.
The highly heat-resistant, low-odor gas-adsorbing laminate of the present invention can have a thermal shrinkage rate of 0% or more and 10% or less when cut into a size of, for example, 10 cm x 10 cm and boiled or heated at a temperature of 90 to 110°C for 10 to 60 minutes, and can suppress the occurrence of orange peel-like changes on the surface.
Furthermore, in the present invention, the heat resistance of the highly heat-resistant, low-odor gas adsorption laminate does not simply mean that there is little thermal deformation or thermal decomposition at high temperatures, but also includes that even after high-temperature treatment, there is little release of gas components originally contained in the resin, gas adsorption properties are maintained, and changes in the odor and taste of the contents can be suppressed.
For example, even if a package containing contents made using a highly heat-resistant, low-odor gas-adsorbing laminate is subjected to a high-temperature boiling treatment at 90°C to 100°C or a heat treatment such as a semi-retort treatment at 100°C to 110°C, the generation of decomposition odors can be suppressed, and the small amount of decomposition odor that is generated and the oxidized odor of the contents can be adsorbed, thereby suppressing changes in the odor and taste of the contents.

Of the gas released from the packaging material itself into the package, a large amount is released from the sealant layer, and the heat seal layer is present at the interface of the joint part of the laminate by heat sealing, etc., and the sealant layer is in contact with the internal space of the package.
Therefore, the highly heat-resistant, low-odor gas-adsorbing sealant layer of the highly heat-resistant, low-odor gas-adsorbing laminate of the present invention generates a small amount of gas itself, has excellent heat-sealing properties, and adsorbs gas from the space where the highly heat-resistant, low-odor gas-adsorbing sealant layer is in contact, thereby adsorbing gas that penetrates into the interior of the package along the interface of the joint and gas that has permeated through the barrier substrate layer, thereby preventing it from reaching the inside of the package.Furthermore, by adsorbing gas present inside the package, an increase in the gas concentration inside the package is prevented, and adhesion or dissolution of gas to or into the contents is prevented, thereby preventing changes in the odor and taste of the contents.

<Gas barrier substrate layer>
The gas barrier substrate layer in the present invention refers to a substrate layer having gas barrier properties, and may be composed of a single layer such as a gas barrier resin film having gas barrier properties and properties such as rigidity as a substrate, or may have a multilayer structure including a layer having gas barrier properties and a substrate layer having properties as a substrate.
The thickness of the gas barrier substrate layer is preferably 5 μm or more and 100 μm or less, and more preferably 7 μm or more and 75 μm or less. If the thickness is less than the above range, the rigidity and/or gas barrier properties may be insufficient, and if the thickness exceeds the above range, the rigidity may be too high, which may reduce workability.

<Base material layer>
The substrate layer may be a resin film, a paper material, or the like, and may be composed of a single layer or a multilayer structure including two or more layers having the same or different compositions.

The thickness of the substrate layer varies depending on the material, but when it is made of a resin film, it is preferably 5 μm or more and 60 μm or less, more preferably 7 μm or more and 45 μm or less.
The resin film used for the base layer can be a film of a thermoplastic resin, and is preferably a thermoplastic resin that has excellent chemical or physical strength, can withstand the conditions for forming a vapor-deposited film of a metal or metal oxide, and can well maintain the properties of the vapor-deposited film without impairing them.

Examples of such resins include polyolefin resins such as polyethylene resins and polypropylene resins, cyclic polyolefin resins, polystyrene resins, acrylonitrile-styrene copolymers (AS resins), acrylonitrile-butadiene-styrene copolymers (ABS resins), poly(meth)acrylic resins, polycarbonate resins, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polyamide resins such as various nylons, polyurethane resins, acetal resins, and cellulose resins.
In the present invention, the resin is preferably a polyester resin, a polyamide resin, or a polyolefin resin, and particularly preferably polyethylene terephthalate (PET), nylon, or polypropylene (PP).

In the present invention, the thermoplastic resin used for the substrate layer can be formed into a film by various film-forming methods.
For example, there may be mentioned a method of using one type of resin to form a film by a film-forming method such as an extrusion method, a cast molding method, a T-die method, a cutting method, or an inflation method, a method of forming a multilayer film by co-extrusion using two or more types of resins, a method of mixing two or more types of resins before film formation and forming a film by the above-mentioned film-forming method, etc. Furthermore, a film may be uniaxially or biaxially stretched using a tenter system, a tubular system, or the like.

Alternatively, one or more resins may be coated on another resin film by applying and drying, or a molten resin may be laminated by a T-die method or the like.
In the present invention, the resin film is preferably a biaxially oriented PET film, a biaxially oriented nylon film, or a biaxially oriented PP film or sheet.

In addition, when forming the resin film, various plastic compounding agents and additives can be added to the resin film for the purpose of improving or modifying, for example, the processability, heat resistance, weather resistance, mechanical properties, dimensional stability, oxidation resistance, slippage, release properties, flame retardancy, mildew resistance, electrical properties, strength, etc. of the film, and the amount of these additives can be any amount ranging from a trace amount to several tens of percent depending on the purpose.
In the above, examples of common additives that can be used include lubricants, crosslinking agents, antioxidants, ultraviolet absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, pigments, modifying resins, and the like.

In addition, adhesive layers can be provided between each layer constituting the base layer or between other layers to improve adhesion, and a desired surface treatment layer can be provided in advance on the surface of each layer, if necessary.

For example, a corona-treated layer, ozone-treated layer, plasma-treated layer, oxidation-treated layer, etc. can be formed by optionally performing pretreatment such as corona discharge treatment, ozone treatment, low-temperature plasma treatment using oxygen gas or nitrogen gas, glow discharge treatment, or oxidation treatment using chemicals.

Alternatively, various coating layers such as a primer coating layer, an undercoating layer, an anchor coating layer, an adhesive layer, and a vapor-deposited anchor coating layer may be optionally formed on the surface of each layer to form a surface treatment layer.
For the various coating agent layers, for example, a resin composition containing a polyester resin, a polyamide resin, a polyurethane resin, an epoxy resin, a phenol resin, a (meth)acrylic resin, a polyvinyl acetate resin, a polyolefin resin such as polyethylene or polypropylene, or a copolymer or modified resin thereof, a cellulose resin, or the like as the main component of the vehicle can be used.

<Gas barrier layer>
The gas barrier layer is a layer that prevents atmospheric gases from passing through the highly heat-resistant, low-odor gas-adsorbing laminate of the present invention from the outside to the inside of the package, in a package made using the highly heat-resistant, low-odor gas-adsorbing laminate of the present invention.
The gas barrier layer preferably contains one or a combination of two or more selected from the group consisting of a gas barrier resin, a metal foil, a metal vapor-deposited film, and a metal oxide vapor-deposited film, and more preferably contains one or a combination of two or more selected from the group consisting of a metal foil, a metal vapor-deposited film, and a metal oxide vapor-deposited film.
In the above, the gas barrier resin may be a gas barrier resin coating film or a gas barrier resin film.
The metal vapor deposition film or metal oxide vapor deposition film may be deposited on a resin film, and the resin film may be a gas barrier resin film or a resin film that constitutes a base layer.

Preferred gas barrier resin films are resin films made from resins such as PET, polybutylene terephthalate, polyethylene naphthalate, polyamide, polyimide, polyvinyl alcohol, and ethylene-vinyl alcohol copolymer.

The metal foil is preferably aluminum foil with a thickness of 3 μm or more and 15 μm or less.

Preferably, the resin film with a metal vapor deposition layer or a metal oxide vapor deposition layer is one in which an aluminum vapor deposition film, a silica vapor deposition film, or an aluminum oxide vapor deposition film is formed on at least one side of the above-mentioned base resin film. Commercially available resin films with an aluminum oxide vapor deposition film include, for example, alumina-vaporized IB-PET-PIR (thickness 12 μm) and silica-vaporized IB-ON-UB (thickness 15 μm) manufactured by Dai Nippon Printing Co., Ltd., which are PET films with alumina vapor-deposited on one side by the PVD method.

The resin film with the metal foil, metal or metal oxide vapor-deposited layer for the gas barrier layer can be bonded to other layers using a dry lamination adhesive.
Alternatively, by using a resin film for the substrate layer as the resin film of the resin film with a metal or metal oxide vapor-deposited layer, it is possible to omit laminating the resin film to the substrate layer.

<Adhesive layer>
The highly heat-resistant, low-odor gas-adsorbing laminate of the present invention can be laminated by providing adhesive layers between the constituent layers and between layers within each layer.
Furthermore, before forming the adhesive layer, an anchor coat layer may be formed in advance on the surface of the layer to be adhered in order to improve adhesiveness.

The adhesive (adhesive composition) that forms the adhesive layer may be heat-curable, ultraviolet-curable, electron beam-curable, or other type, and may be in any form, such as aqueous, solution, emulsion, or dispersion. Its form may be film/sheet, powder, or solid, and its adhesive mechanism may be any of chemical reaction, solvent evaporation, thermal melting, or thermal pressure.

Examples of such adhesives include polyvinyl acetate adhesives such as polyvinyl acetate and vinyl acetate-ethylene copolymers, polyacrylic acid adhesives made from copolymers of polyacrylic acid and polystyrene, polyester, polyvinyl acetate, etc., cyanoacrylate adhesives, ethylene copolymer adhesives made from copolymers of ethylene and monomers such as vinyl acetate, ethyl acrylate, acrylic acid, and methacrylic acid, cellulose adhesives, polyurethane adhesives, polyester adhesives, polyamide adhesives, polyimide adhesives, polyolefin adhesives, amino resin adhesives made from urea resin or melamine resin, phenol resin adhesives, epoxy adhesives, reactive (meth)acrylic adhesives, elastomer adhesives made from chloroprene rubber, nitrile rubber, styrene-butadiene rubber, etc., silicone adhesives, and inorganic adhesives made from alkali metal silicates, low-melting point glass, etc.
When a laminate is formed by co-extrusion and film formation using an inflation method, polyester-based and polyolefin-based adhesives are preferred among the above.

In one embodiment of the present invention, the adhesive layer may be a layer made of any of an adhesive for EC (extrusion coating), an adhesive for dry lamination, an adhesive for non-solvent lamination, and the like.
When an EC adhesive is used, there are no particular limitations, but for example, the adhesive is first heated and melted, expanded and stretched in the required width direction using a T-die or the like, and extruded in a curtain shape, allowed to flow down onto the layer to be adhered, and then sandwiched between a rubber roll and a cooled metal roll, thereby simultaneously forming an adhesive layer and adhering and laminating to the layer to be adhered.

In another embodiment, the adhesive layer may be formed by sand lamination. In this case, any resin that can be heated and melted and applied in an extruder can be used for the adhesive layer. Specifically, the resins listed above as thermoplastic resins with heat sealability can be preferably used.

When using a dry laminating adhesive, the adhesive dispersed or dissolved in a solvent is applied to one film and dried, and then the other film is placed on top of it and laminated. After that, the adhesive is cured by aging at 30 to 120°C for several hours to several days, allowing the two films to bond and laminate.

When using a non-solvent laminating adhesive, the adhesive itself is applied to the layer to be adhered without being dispersed or dissolved in a solvent and allowed to dry. The film that will form the other layer is then laminated on top of it, and the adhesive is then cured and laminated by aging at 30-120°C for several hours to several days.

The adhesive for dry lamination or the adhesive for non-solvent lamination can be used by coating, for example, by roll coating, gravure roll coating, kiss coating, etc., and the coating amount is preferably 0.1 to 10 g/m ² (dry state). By setting the coating amount within the above range, good adhesion can be obtained.

(Anchor coat layer)
The anchor coat layer can be formed from any anchor coat agent.
Examples of anchor coating agents that can be used include organic titanium-based, isocyanate (urethane-based), polyethyleneimine-based, acid-modified polyethylene-based, polybutadiene-based, polyacrylic-based, polyester-based, epoxy-based, polyvinyl acetate-based, cellulose-based, and other anchor coating agents.

<Highly heat-resistant, low-odor, gas-absorbing sealant layer>
The highly heat-resistant, low-odor, gas-adsorbing sealant layer contains a highly heat-resistant, low-odor resin with heat-sealing properties and a gas adsorbent, and therefore has excellent heat-sealing properties and high heat resistance that can withstand temperatures from boiling to semi-retort heating treatment (90 to 110°C), has little thermal shrinkage, inhibits the occurrence of citrus peel, and emits only a small amount of gas (including elution of gas components) from the outside.It can adsorb gases that come into contact with the outside and inhibit changes in the taste and odor of the packaged contents due to these gases.

The highly heat-resistant, low-odor, gas-adsorbing sealant layer may have a single layer structure or a multi-layer structure of two or more layers.
For example, it may be composed of a single layer of a gas adsorption layer containing a highly heat-resistant, low-odor resin and a gas adsorbent, or it may be composed of two layers of a gas adsorption layer containing a highly heat-resistant, low-odor resin and a gas adsorbent and a heat-seal layer containing a highly heat-resistant, low-odor resin, or it may be composed of three layers in which a gas adsorption layer is sandwiched between two heat-seal layers.

The content of the high heat-resistant, low odor resin in the total resin contained in the high heat-resistant, low odor gas-adsorbing sealant layer is preferably 70% by mass or more and 100% by mass or less, more preferably 80% by mass or more and 100% by mass or less, and even more preferably 90% by mass or more and 100% by mass or less. If the content is less than the above range, the low gas release properties of the high heat-resistant, low odor gas-adsorbing sealant layer may be insufficient, while if the content is more than the above range, it may be difficult to balance various physical properties and workability, but the low gas release properties will not be significantly improved.

The content of the gas adsorbent in the layer containing the gas adsorbent is preferably 0.1% by mass or more and 30% by mass or less, and more preferably 0.5% by mass or more and 28% by mass or less. If the content is less than the above range, the gas adsorption effect may be insufficient, and if the content is more than the above range, the film formability may be deteriorated.
Here, the layer containing the gas adsorbent refers to the entire high heat resistant, low odor gas adsorbing sealant layer when the high heat resistant, low odor gas adsorbing sealant layer is composed of only one layer, and refers to, for example, the gas adsorbing layer when the high heat resistant, low odor gas adsorbing sealant layer is a multi-layer structure having a gas adsorption layer, a heat seal layer, etc.

When the highly heat-resistant, low-odor gas-adsorbing sealant layer of the present invention has a multilayer structure having a gas adsorption layer, a heat-sealing layer, etc., in order to improve heat-sealing properties and lamination properties, it is preferable that the outermost layer on at least one side of the highly heat-resistant, low-odor gas-adsorbing sealant layer be a heat-sealing layer, and it is more preferable that the outermost layers on both sides be heat-sealing layers.
Furthermore, the highly heat-resistant, low-odor resin contained in the gas adsorption layer and the highly heat-resistant, low-odor resin contained in the heat seal layer may be the same or different.

The highly heat-resistant, low-odor, gas-adsorbing sealant layer is preferably a layer made of a low-outgassing, gas-adsorbing sealant film having the composition and layer structure described above.

The high heat resistance, low odor, gas adsorption sealant layer can adjust its gas adsorption and low gas release properties by adjusting the layer thickness.
The thickness of the highly heat-resistant, low-odor, gas-adsorbing sealant layer is preferably 25 μm or more and 150 μm or less, more preferably 30 μm or more and 100 μm or less, in order to achieve a balance between good heat-sealing properties, gas adsorption properties, and low gas release properties. If the thickness is thinner than the above range, the heat-sealing properties and/or gas adsorption properties may be insufficient, and if the thickness is thicker than the above range, the low gas release properties may be inferior.

The high heat resistant, low odor, gas adsorption sealant layer may further contain small amounts of slip agents, antiblocking agents, antioxidants, solvents, and other additives.
The highly heat-resistant, low-odor, gas-adsorbing sealant layer preferably contains an antioxidant to suppress the generation of gases released due to resin deterioration in high-temperature environments. Conversely, it is preferable to limit the use of additives that may increase the amount of gas released at high temperatures.

(gas to be adsorbed)
The gas components to be adsorbed in the present invention are mainly gas components originally contained in the highly heat-resistant, low-odor gas adsorption laminate of the present invention, particularly the highly heat-resistant, low-odor gas adsorption sealant layer, and gas components consisting of resin decomposition products generated by decomposition of the resin in the highly heat-resistant, low-odor gas adsorption laminate due to heating such as heat sealing or irradiation with UV or EB, etc.
Here, the gas components originally contained in the highly heat-resistant, low-odor gas adsorption laminate include gas components contained in the raw materials constituting each layer, and gas components generated due to the thermal history, etc., when producing the highly heat-resistant, low-odor gas adsorption laminate.
In particular, examples of such gas components include those originally contained in the highly heat-resistant, low-odor, gas-adsorbing sealant layer, those contained in the raw materials that constitute the highly heat-resistant, low-odor, gas-adsorbing sealant layer, and those gas components that are generated due to the thermal history, etc., when forming the low-gas-releasing, gas-adsorbing sealant layer or the low-gas-releasing, gas-adsorbing sealant film.

Specific examples of gases to be adsorbed include organic substances with relatively small molecular weights.
The organic matter is a gas component derived from a layer containing an organic matter in the highly heat-resistant, low-odor, gas-adsorbing laminate, particularly a highly heat-resistant, low-odor, gas-adsorbing sealant layer. Many of the gas component compounds have 1 to 16 carbon atoms, and examples of the gas component include hydrocarbons, aldehydes, ketones, and carboxylic acids.

Specific examples of hydrocarbons include propane, propene, butane, isobutane, 2-methylbutane, butene, isobutene, 2-methylpentane, 3-ethylpentane, 2,2-dimethylpentane, 3,3-dimethylpentane, hexane, cyclohexane, 2-methylhexane, 3-methylhexane, 2,5-dimethylhexane, heptane, 2-methylheptane, 3-methylheptane, 3-ethylheptane, 2,2,4,6,6-pentamethylheptane, 3-ethyl-3-methylheptane, 3-methylheptene, octane, 2-methyloctane, 4-ethyloctane, nonane, 3-methylnonane, decane, and dodecane.

Specific examples of aldehydes include formaldehyde, acetaldehyde, 2-methylpropanal, and 3-methylbutanal.

Specific examples of ketones include acetone, MEK, MIBK, and 3,3-dimethyl-2-butanone.

Specific examples of carboxylic acids include acetic acid, isovaleric acid, 2-methylpropanoic acid, and 2,2-dimethylpropanoic acid.

Hydrocarbons, aldehydes, ketones, and carboxylic acids often originate from the thermal history of the highly heat-resistant, low-odor gas-adsorbing sealant layer.

[Gas adsorption layer]
The gas adsorption layer is a layer containing a gas adsorbent and having high gas adsorption properties, and preferably further contains a highly heat-resistant, low-odor resin as a binder resin to maintain low gas release properties. However, other resins and various additives such as antioxidants can be contained within a range that does not significantly impair the gas adsorption properties and low gas release properties.
The highly heat-resistant, low odor gas-adsorbing sealant layer may contain one gas-adsorbing layer or two or more layers having the same or different compositions.

To ensure good gas adsorption, the thickness of the gas adsorption layer is preferably 5 μm or more and 80 μm or less, and more preferably 7 μm or more and 75 μm or less. If the thickness is thinner than this range, gas adsorption may be insufficient. If the thickness is thicker than this range, gas adsorption may not improve significantly, and the high-heat-resistant, low-odor gas adsorption laminate may become too rigid, reducing workability.

[Heat seal layer]
The heat seal layer is a layer containing a highly heat-resistant, low-odor resin and has high heat sealability. In order to have high heat sealability, it is preferable that the heat seal layer does not contain a gas adsorbent.
In order to achieve both high heat-sealing properties and low gas release properties, the heat-sealing resin contained therein is preferably a highly heat-resistant, low-odor resin.
However, various additives such as gas adsorbents, other resins, and antioxidants may be contained within the range that does not significantly impair the heat sealability and low gas release properties.
The highly heat-resistant, low-odor, gas-adsorbing sealant layer may contain one heat-sealing layer or two or more layers having the same or different compositions.

To ensure good heat sealing properties, the thickness of the heat seal layer is preferably 3 μm or more and 30 μm or less, and more preferably 5 μm or more and 20 μm or less. If the thickness is thinner than this range, the heat sealing properties may be insufficient. If the thickness is thicker than this range, the heat sealing properties may not be significantly improved, and the rigidity of the high heat resistance, low odor gas adsorption laminate may become too weak, resulting in reduced workability.

[High heat resistant low odor resin]
High heat resistance and low odor resin is a resin that has high heat resistance and emits a small amount of gas, and the amount of gas emitted varies depending on the shape and thermal history of the resin.
By incorporating a high heat-resistant, low odor resin with heat sealing properties into a high heat-resistant, low odor gas-adsorbing sealant layer, the high heat-resistant, low odor gas-adsorbing sealant layer is endowed with heat sealing properties, the amount of gas released is reduced, and the passage and release of gas can be suppressed.

The amount of gas released from a highly heat-resistant, low-odor resin is highly correlated with the concentration of elutable total organic carbon (TOC) contained in the highly heat-resistant, low-odor resin, which elutes during boiling or semi-retort treatment.
TOC is the concentration of the total amount of organic matter (organic carbon) in water that can be oxidized, expressed as a carbon concentration. It is used as one of the representative water quality indicators and is standardized by JIS K0805 (Total Organic Carbon (TOC) Automatic Meter) etc.

The concentration of extractable total organic carbon (TOC) contained in the film made of the high heat resistance, low odor resin of the present invention is preferably 1.5 ppm or more and 250 ppm or less, and more preferably 5 ppm or more and 200 ppm or less. It is difficult to prepare a film with a concentration lower than this range, and it is difficult to demonstrate a significant difference in practical effect. If the concentration is higher than this range, the gas release properties of the high heat resistance, low odor resin may be insufficient.

The reason why the concentration of elutable TOC in the high heat resistant, low odor resin as a single raw material is measured in a film state rather than in the state of raw material pellets, etc., is that the high heat resistant, low odor resin may be subjected to various thermal histories, etc., during the formation of the high heat resistant, low odor gas adsorption sealant layer or during the production of the high heat resistant, low odor gas adsorption sealant film, which may increase the amount of eluted TOC.
The concentration of extractable total organic carbon (TOC) contained in the film made of the above-mentioned highly heat-resistant, low-odor resin can be measured as follows.
For example, a film made of the highly heat-resistant, low-odor resin of the present invention is placed in a gas sampling bag, filled with distilled water as the filling water, boiled to elute organic carbons, cooled, and then stored, after which the TOC concentration of the filled water is measured.The TOC concentration of the filled water before filling is subtracted as a blank to calculate the increase in TOC concentration, and the concentration of leachable TOC contained in the film made of the highly heat-resistant, low-odor resin can be further calculated.

Specific conditions include a boiling temperature of 90°C to 100°C, a boiling time of 10 to 60 minutes, a storage temperature of 25°C to 50°C, and a storage period of 1 day to 4 weeks. It is preferable to measure the TOC concentration of the filled water using a total organic carbon meter or HS-GC.

The density of the high heat resistance, low odor resin is preferably 0.920 g/cm or ^more and 0.960 g/cm or ^less , and more preferably 0.925 g/cm ^{or more} and 0.955 g/cm or ^less . If the density is within the above range, the amount of gas released can be reduced.

The MFR (melt flow rate) of the high heat resistance, low odor resin is preferably 0.2 g/10 min or more and 10 g/10 min or less, and more preferably 0.5 g/10 min or more and 7 g/10 min or less.
If the FR is within the above range, even when mixed with other resins or gas adsorbents, the resin can maintain a good MFR and exhibit good film-forming properties and adhesive properties.

As the highly heat-resistant, low-odor resin, a polyethylene-based resin (low gas-releasing polyethylene-based resin) is preferred because it has excellent heat-sealing properties, resistance to UV or EB irradiation and heating, and resistance to decomposition.
Low gas release polyethylene resins originally contain a small amount of gas that can be released, and are resistant to UV or EB irradiation and heating and are not easily decomposed, so that the amount of gas released can be reduced.

Specific examples of polyethylene types in low-gassing polyethylene resins include, but are not limited to, low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl methacrylic acid copolymer, ethylene-propylene copolymer, and other low-gassing copolymers, as well as mixtures of these resins.

Among the above, one or a combination of two or more selected from the group consisting of HDPE, MDPE, LDPE and LLDPE is preferred.
The LLDPE is preferably one or a combination of two or more selected from the group consisting of C4-LLDPE, C6-LLDPE, and C8-LLDPE, and C6-LLDPE is more preferred.

Here, C4-LLDPE is a linear low-density polyethylene made from a copolymer of ethylene and 1-butene, C6-LLDPE is a linear low-density polyethylene made from a copolymer of ethylene and 1-hexene and/or 4-methyl-1-pentene, and C8-LLDPE is a linear low-density polyethylene made from a copolymer of ethylene and 1-octene.
Each of these molecular structures has an ethylene-derived LLDPE main chain with side chains of 4, 6, and 8 carbon atoms derived from 1-butene, 1-hexene and/or 4-methyl-1-pentene, and 1-octene, respectively.

In order to keep the amount of released gas contained in the resin low, for example, it is effective to reduce the amount of unreacted raw materials, low-molecular-weight products, and by-products, or to remove the polymerization catalyst when producing the resin. Specifically, methods include improving the purity of raw materials, precisely controlling conditions such as reaction temperature and pressure, removing unreacted raw materials, low-molecular-weight products, by-products, and polymerization catalyst by distillation or washing, and preventing oxidation due to exposure to oxygen in the air at high temperatures.
Another method is to limit the use of additives that may increase the amount of outgassing when the resin is pelletized or filmed, thereby preventing oxidation due to high temperatures. Specific additives include lubricants, antioxidants, antiblocking agents, solvents, etc.

[Gas adsorbent]
In the present invention, the gas adsorbent preferably contains one or a combination of two or more selected from the group consisting of hydrophobic zeolite, molecular sieve, metal organic framework (MOF), and activated carbon.

(Hydrophobic Zeolite)
In the present invention, the hydrophobic zeolite used as the gas adsorbent preferably has a SiO ₂ /Al ₂ O ₃ molar ratio of 2/1 to 10,000/1, more preferably 30/1 to 2,000/1. When the molar ratio is within the above range, an excellent balance between hydrophobicity and pore size is achieved, and good gas adsorption properties can be achieved.
Hydrophobic zeolite can be preferably used because it maintains its gas component adsorption effect even when exposed to temperatures of 230° C. or higher.
The hydrophobic zeolite may have any external shape such as a sphere, a rod, an ellipse, or the like, and may be in any form such as a powder, a lump, or a granule. However, from the viewpoints of uniform dispersibility, kneading properties, film-forming properties, and the like when dispersed in a resin, a powder form is preferred.

In the present invention, the average particle size of the hydrophobic zeolite can be selected appropriately depending on the application, but the average particle size is preferably 0.01 μm or more and 30 μm or less, and more preferably 0.1 μm or more and 20 μm or less. Here, the average particle size is a value measured by dynamic light scattering.
If the average particle size is smaller than the above range, the hydrophobic zeolite tends to aggregate and the dispersibility tends to decrease, whereas if the average particle size is larger than the above range, the film-forming properties of the layer containing the hydrophobic zeolite tend to be poor, making it difficult to add a large amount of hydrophobic zeolite, and furthermore, the surface area is reduced, which may result in insufficient gas adsorption effect.

Because hydrophobic zeolites are hydrophobic, they have difficulty adsorbing highly polar molecules such as water molecules. Conversely, they have a high affinity for low-polarity organic gases, and a high affinity for other low-polarity gas components, hydrophobic gases, and lipophilic gases (including solvent-based gases), making them easy to adsorb. In other words, they excel at adsorbing gas components that do not have functional groups. Furthermore, when alkali metals or alkaline earth metals such as Ca, Na, and K are present on the zeolite surface, the zeolite surface exhibits basicity, making it easy to adsorb acidic gases through a neutralization reaction.

(molecular sieve)
Molecular sieves are a type of hydrophilic zeolite that adsorb highly polar molecules into their porous pores, particularly water (water vapor) molecules.
Molecular sieves are designated as 3A, 4A, 5A, or 13X depending on the type of raw zeolite, with the number indicating the approximate pore diameter (angstroms) and the capital letter indicating the type of zeolite, with A representing LTA zeolite and X representing FAU zeolite.
3A is suitable for adsorbing acetonitrile and ethanol, 5A is suitable for adsorbing aromatic compounds, and 13X is suitable for adsorbing large molecules such as long-chain tertiary amines.

(Metal-organic framework (MOF))
For metal organic frameworks (MOFs), salts composed of metal ions and organic ligands are preferably used.
The metal-organic framework can have a porous structure with a smaller pore diameter and a larger specific surface area compared to common activated carbon or zeolite.
Specific examples of the metal organic framework include aluminum fumarate, zirconium fumarate, copper trimesate, aluminum trimesate, zirconium trimesate, iron trimesate, aluminum terephthalate, zirconium terephthalate, 2-methylimidazole zinc, magnesium formate, zinc benzene-1,3,5-tribenzoate, zinc 2,6-naphthalene-dicarboxylate, aluminum aminobenzene-1,4-dicarboxylate, magnesium 2,5-dioxidobenzene-1,4-dicarboxylate, magnesium 4,4-dioxidobiphenyl-3,3-dicarboxylate, and the like, and one or a combination of two or more selected from this group can be used.

The pore diameter of the metal organic framework is preferably 0.3 nm or more and 3.0 nm or less, and more preferably 0.3 nm or more and 2.0 nm or less. Examples of pore diameters include 1.1 nm and 0.6 nm for 2-methylimidazole zinc salt, 0.90 nm or 0.3 nm and 0.5 nm for copper trimesate, 0.8 nm and 0.5 nm for aluminum terephthalate, 1.1 nm and 0.5 nm for aluminum fumarate, 0.7 nm and 0.6 nm for aluminum trimesate, 0.46 nm, 1.15 nm, and 1.8 nm for zirconium trimesate, 0.3 nm and 0.4 nm for magnesium formate, and 2.5 nm and 2.9 nm for iron trimesate.

The specific surface area of the metal organic framework can be expressed as a BET specific surface area or a Langmuir specific surface area, and in the case of a BET specific surface area, it is preferably 400 m ² /g or more and 4000 m ² /g or less, and more preferably 900 m ² /g or more and 2100 m ² /g or less.
The Langmuir specific surface area is preferably 500 m ² /g or more and 5000 m ² /g or less, and more preferably 1200 m ² /g or more and 2400 m ² /g or less.

Examples of BET specific surface areas are 1350 ^{m 2} /g for zinc 2-methylimidazole, 1500 ^{m 2} /g for copper trimesate, 950 ^{m 2} /g for aluminum terephthalate, 1000 ^{m 2} /g for aluminum fumarate, 1100 m ² /g for aluminum trimesate, 2060 ^{m 2} /g for zirconium trimesate, 400 m ² /g for magnesium formate, and 3600 ^{m 2} /g for zinc benzene-1,3,5-tribenzoate.
Examples of Langmuir specific surface areas are 1800 ^{m 2} /g for zinc 2-methylimidazole, 2000 ^{m 2} /g for copper trimesate, 1500 ^{m 2} /g for aluminum terephthalate, 1200 ^{m 2} /g for aluminum fumarate, 1500 m ² /g for aluminum trimesate, 2390 ^{m 2} /g for zirconium trimesate, 500 ^{m 2} /g for magnesium formate, and 5000 m ² /g for zinc benzene-1,3,5-tribenzoate.

The above metal organic frameworks can absorb gases in amounts corresponding to their molecular size and specific surface area, depending on their pore diameter. For example, 2-methylimidazole zinc salt is excellent at absorbing lower hydrocarbons and carbon dioxide, copper trimesate is excellent at absorbing lower hydrocarbons (especially methane) and carbon dioxide, aluminum terephthalate is excellent at absorbing methane, water vapor, and carbon dioxide, aluminum fumarate and zircon trimesate are excellent at absorbing water vapor, and aluminum trimesate is excellent at absorbing lower hydrocarbons (especially methane) and water vapor.

In the present invention, it is preferable to use one or a combination of two or more of the above metal-organic frameworks selected from the group consisting of 2-methylimidazole zinc salt, copper trimesate, and aluminum terephthalate.

(activated carbon)
Activated carbon is a porous substance that is primarily composed of carbon and also contains oxygen, hydrogen, calcium, etc., and has been chemically or physically processed. Because it is porous, it has a large surface area relative to its volume, and therefore has the ability to adsorb many substances.
Because the surface of activated carbon is non-polar, it has a low adsorption capacity for polar molecules and is therefore more likely to selectively adsorb granular organic matter that is smaller than the pores of activated carbon.

(Improved dispersion by making gas adsorbent into a masterbatch)
The gas adsorbent may be directly mixed and melt-kneaded with the other components of the high heat-resistant, low odor gas adsorption sealant layer. However, it is preferable to improve the dispersibility of the gas adsorbent in the high heat-resistant, low odor gas adsorption sealant layer by using a so-called masterbatch method, in which the gas adsorbent is mixed at a high concentration with a thermoplastic resin and then melt-kneaded (melt blended) to prepare a masterbatch, and this is then mixed with the other components of the high heat-resistant, low odor gas adsorption sealant layer in a ratio corresponding to the target content, and melt-kneaded.
By adopting the masterbatch method, even when a gas adsorbent that is prone to aggregation is used, the gas adsorbent can be efficiently and uniformly dispersed in the highly heat-resistant, low-odor gas adsorption layer sealant film.

The mass ratio of gas adsorbent to thermoplastic resin in the masterbatch is not particularly limited, but is preferably 3/97 or more and 50/50 or less, and more preferably 5/95 or more and 40/60 or less.
As a method for kneading the gas adsorbent and the thermoplastic resin, various kneading methods can be applied.
The thermoplastic resin used in the masterbatch can be of a type and content within a range that does not significantly adversely affect the heat sealability, film formability, gas adsorption, or low gas release properties of the entire high heat resistant, low odor gas adsorption sealant layer, but a resin that is highly compatible with other resins, such as the heat sealable resin and the high heat resistant, low odor resin contained in the high heat resistant, low odor gas adsorption sealant layer, and has comparable heat sealability is preferred, and the resin may be the same as or different from these. For example, it may be a high heat resistant, low odor resin.

Specific examples of thermoplastic resins used in masterbatches include general-purpose polyethylene, polypropylene, methylpentene polymers, acid-modified polyolefin resins, and other polyolefin resins, as well as mixtures of these resins. However, the resins are not limited to these, and any type of thermoplastic resin can be selected according to the purpose.

The MFR (melt flow rate) of the thermoplastic resin used in the masterbatch is preferably 0.2 g/10 min or more and 10 g/10 min or less. An MFR within this range facilitates melt-kneading with the gas adsorbent, makes it easier to disperse the gas adsorbent in the high heat-resistant, low odor, gas-adsorbing sealant layer, and helps maintain the film-forming properties of the high heat-resistant, low odor, gas-adsorbing sealant layer and high heat-resistant, low odor, gas-adsorbing sealant film.

[Method for producing a highly heat-resistant, low-odor gas-adsorbing laminate]
The manufacturing method described below is an example and does not limit the present invention.
The layers constituting the highly heat-resistant, low-odor gas-adsorbing laminate can be formed by any method, such as wet lamination, dry lamination, solventless dry lamination, extrusion lamination, T-die coextrusion molding, coextrusion lamination, inflation molding, or the like.
The obtained highly heat-resistant, low-odor gas-adsorbing laminate can 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, adhesives, printing, metallizing (plating, etc.), machining, and surface treatments (antistatic treatment, corona discharge treatment, plasma treatment, photochromism treatment, physical vapor deposition, chemical vapor deposition, coating, etc.).

As an example, the following describes the production of a highly heat-resistant, low-odor, gas-adsorbing laminate (reduced-pressure packaging material) having a layer structure of gas barrier substrate layer [substrate layer 1/adhesive layer/substrate layer 2/adhesive layer/gas barrier layer]/adhesive layer/highly heat-resistant, low-odor, gas-adsorbing sealant layer [heat seal layer 1/gas adsorption layer/heat seal layer 2].

(Method for producing a highly heat-resistant, low-odor, gas-adsorbing sealant film)
For example, a gas adsorption layer resin composition for the gas adsorption layer and a high heat resistance, low odor resin for the heat seal layer are separately prepared and prepared, and then a high heat resistance, low odor gas adsorption sealant film having the following layer structure can be obtained by an inflation method.
Layer structure: heat seal layer 1/gas adsorption layer/heat seal layer 2
Alternatively, the gas adsorption layer resin composition for the gas adsorption layer and the highly heat-resistant, low-odor resin for the heat seal layer may be extruded or coextruded onto a release film by extrusion coating, and then the release film may be removed. In the case of the extrusion coating method, lamination may be performed via an adhesive layer, if necessary.

(Preparation of Highly Heat-Resistant, Low-Odor Gas-Adsorbing Laminate)
Next, the low outgassing gas adsorption sealant film obtained above for the high heat resistance, low odor gas adsorption sealant layer, the substrate film 1 for the substrate layer 1, the substrate film 2 for the substrate layer 2, and the aluminum foil for the gas barrier layer are bonded together in this order by dry lamination (coating amount: 3.5 g/m2, drying temperature: 70°C) using a DL adhesive for the adhesive layer to obtain a high heat resistance, low odor gas adsorption laminate having the above layer configuration.

<High heat resistance, low odor, gas adsorption packaging material>
The highly heat-resistant, low-odor gas-adsorbing packaging material of the present invention is a packaging material made from the highly heat-resistant, low-odor gas-adsorbing laminate of the present invention, and may be the same as the highly heat-resistant, low-odor gas-adsorbing laminate, and may further include various functional layers, printed layers, etc., as necessary.
Due to the above characteristics, the highly heat-resistant, low odor, gas-adsorbing packaging material is suitable as a packaging material for vacuum packaging, similar to the highly heat-resistant, low odor, gas-adsorbing laminate of the present invention.
The highly heat-resistant, low-odor, gas-adsorbing packaging material of the present invention can also be subjected to lamination (dry lamination or extrusion lamination), bag-making, and other post-treatments.
Specific examples of the highly heat-resistant, low-odor, gas-adsorbing packaging material of the present invention include, for example, gas-adsorbing packaging materials with low gas release for various vacuum packaging applications.
Specific examples of vacuum packaging include packaging materials for fresh foods (such as cheese, salami, and sausages that are not sterilized after vacuum packing) and boiled and retort foods (which are sterilized after vacuum packing) in food applications, and packaging materials for heat insulating panels and rust-preventive packaging materials for metal parts or metal equipment in industrial applications.

<Highly heat-resistant, low-odor, gas-absorbing packaging>
The highly heat-resistant, low-odor, gas-adsorbing packaging body of the present invention is a packaging body made using the highly heat-resistant, low-odor, gas-adsorbing packaging material of the present invention, and specific examples include food packaging bodies, heat-insulating panels, and rust-proof packaging bodies.

<Measurement of heat resistance of highly heat-resistant, low-odor gas adsorption laminate>
The highly heat-resistant, low-odor gas-adsorbing laminate of the present invention can have a thermal shrinkage rate of 0% or more and 10% or less when cut into a size of, for example, 10 cm x 10 cm and boiled or heated at a temperature of 90 to 110°C for 10 to 60 minutes, and can suppress the occurrence of orange peel-like changes on the surface.
The thermal shrinkage rate is the rate of change in length, and may be, for example, the average value of the thermal shrinkage rates of the lengths of each side.
In addition, in the present invention, heat resistance does not simply refer to little thermal deformation or thermal decomposition at high temperatures, but also includes little release of gas components originally contained in the resin and maintaining gas adsorption properties.
For example, even if a package containing contents made using a highly heat-resistant, low-odor gas-adsorbing laminate is subjected to a high-temperature boiling treatment at 90°C to 100°C or a heat treatment such as a semi-retort treatment at 100°C to 110°C, the generation of decomposition odors can be suppressed, and the small amount of decomposition odor that is generated and the oxidized odor of the contents can be adsorbed, thereby suppressing changes in the odor and taste of the contents.

<High heat resistance, low odor resin film, high heat resistance, low odor gas adsorption laminate, elutable TO contained in
C concentration measurement and calculation>
The concentration of leachable total organic carbon (TOC) contained in the above-mentioned highly heat-resistant, low-odor resin film and highly heat-resistant, low-odor gas-adsorbing sealant film can be measured and calculated as follows.
The highly heat-resistant, low-odor resin film and the highly heat-resistant, low-odor gas-adsorbing laminate are collectively referred to as test piece film.
First, the test piece film is placed in a gas sampling bag, which is filled with distilled water as filling water and then sealed.
The water is then boiled to elute the organic carbon, and the water is then cooled to room temperature (about 35° C.) and left to stand for a certain period of time, after which the TOC concentration in the water is measured.
Next, the TOC concentration of the filling water before filling is subtracted as a blank to calculate the increase in TOC concentration, and the concentration of elutable TOC contained in the test piece film is calculated.
The gas sampling bag may be a SMART BAG manufactured by GL Sciences, and the filling water may be distilled water for high performance liquid chromatography.
The TOC concentration of the filling water can be measured using a total organic carbon meter or HS-GC, for example, a TOC-L total organic carbon meter (manufactured by Shimadzu Corporation, etc.).

Specific conditions include a boiling temperature of 90°C to 100°C, a boiling time of 10 to 60 minutes, a storage temperature of 25°C to 50°C, and a storage period of 1 day to 4 weeks. When the test piece film is a resin film made of a highly heat-resistant, low-odor resin, the boiling conditions are preferably 90°C for 30 minutes and the storage conditions are 35°C for 2 weeks.
When the test piece film is a highly heat-resistant, low-odor gas-adsorbing laminate, the boiling conditions are preferably 90° C. for 30 minutes and the storage conditions are preferably room temperature (35° C.) for 2 weeks.

Below is shown an example in which the concentration C of elutable TOC contained in the test piece film is calculated from the increased concentration of TOC in the filling water.
Filled water (distilled water) weight: W1 = 1000 [g]
Test piece film
Density: S [g/cm ³ ]
Size: 15cm x 44cm x 50μm thick, 2 sheets
Weight: W2 = 15 x 44 x 50 x 10 ^-4 x 2 x S = 6.6 x S [g]
Concentration of elutable TOC contained: C [ppm]
Increase in TOC concentration in filling water: X [ppm]
Then,
Total weight of elutable TOC contained in the test piece film = C × W2 [g]
This dissolves in W1 [g] of water, so
X=C×W2/W1=C×6.6×S×10 ^-3 [ppm]
The TOC concentration C of the elutable TOC contained in the test piece film is calculated by the following formula:
C=X/(6.6×S×10 ^-3 ) [ppm]
For example, if the density S of the test piece film is 1.00 [g/cm ³ ] and the increase X in the TOC concentration of the filling water is 0.01 [ppm], then:
C=0.01/(6.6×1.00×10 ^-3 )=1.51 [ppm]
It is calculated as follows:

The elutable TOC concentration in the high heat resistance, low odor gas adsorption laminate measured under the above conditions is preferably 0.01 ppm or more and 1.5 ppm or less, and more preferably 0.02 ppm or more and 1.2 ppm or less. It is difficult to produce a laminate with a concentration lower than the above range, and it is difficult to show a significant difference in practical effect. If the concentration is higher than the above range, the low odor property of the high heat resistance, low odor gas adsorption laminate may be insufficient. From the viewpoint of achieving both cost and performance, the above range is preferable.

Details of the raw materials used in the examples are as follows.
[High heat resistant low odor resin]
High heat resistance, low odor resin 1: Ultzex 3520L manufactured by Prime Polymer Co., Ltd. C6-LLDPE, density 0.931 g/cm ³ , MFR 2.1 g/10 min. Extractable TOC concentration contained in the resin film 42.3 ppm.
High heat resistance, low odor resin 2: Ultzex 4020L manufactured by Prime Polymer Co., Ltd. C6-LLDPE, density 0.937 g/cm ³ , MFR 2.3 g/10 min. Extractable TOC concentration contained in the resin film 32.5 ppm.
High heat resistance, low odor resin 3: Hi-Zex 3300F manufactured by Prime Polymer Co., Ltd. HDPE, density 0.949 g/cm ³ , MFR 1.1 g/10 min. Extractable TOC concentration contained in the resin film 24.4 ppm.

[General-purpose polyethylene]
General-purpose polyethylene 1: Evolue SP4020 manufactured by Prime Polymer Co., Ltd. C6-LLDPE, density 0.937 g/cm ³ , MFR 1.7 g/10 min. TOC concentration in extracted water 2.85 ppm, leachable TOC concentration contained in resin film 461 ppm.
General-purpose polyethylene 2: Evolue SP1520 manufactured by Prime Polymer Co., Ltd. C6-LLDPE, density 0.913 g/cm ³ , MFR 2.0 g/10 min. TOC concentration of tree extract water 3.05 ppm, TOC concentration of elutable contained in resin film 506 ppm.

[Gas adsorbent]
Hydrophobic zeolite 1: Mizusawa Sieves EX-122 hydrophobic zeolite manufactured by Mizusawa Industrial Chemicals, Ltd. SiO ₂ /Al ₂ O ₃ molar ratio=32/1, average particle size 2.5 to 5.5 μm.
Hydrophobic zeolite 2: Silton MT400, a hydrophobic zeolite manufactured by Mizusawa Industrial Chemicals, Ltd. SiO ₂ /Al ₂ O ₃ molar ratio=400/1, average particle size 5 to 7 μm.
Hydrophobic zeolite 3: Silton MT-2000 hydrophobic zeolite manufactured by Mizusawa Industrial Chemicals, Ltd. SiO ₂ /Al ₂ O ₃ molar ratio=2000/1, average particle size 0.8 μm.

[Gas barrier substrate layer film]
Base film 1: PET film manufactured by Toyobo Co., Ltd., Espet T4102, thickness 12 μm.
Base film 2: IB-PET-PIR manufactured by Dai Nippon Printing Co., Ltd. Alumina-deposited PET film with a barrier coating resin layer. Thickness: 12 μm.
Aluminum foil 1: Aluminum foil manufactured by Toyo Aluminum Co., Ltd., 6 μm thick.

[Functional layer film]
Functional film 1: Biaxially oriented nylon film manufactured by Unitika Ltd., Emblem ON, thickness 15 μm. Enhanced toughness, flexibility, and burst resistance.

[glue]
DL Adhesive 1: Adlock RU77T/H7 manufactured by Rock Paint Co., Ltd. A polyester adhesive.

[Preparation of Masterbatch]
The masterbatch used in the gas adsorption layer was prepared as follows.

(Preparation of Masterbatch 1)
High heat-resistant, low-odor resin 1 and hydrophobic zeolite 1 were melt-blended in the following ratio to obtain masterbatch 1 (MB1).
High heat resistant, low odor resin 1 70 parts by mass Hydrophobic zeolite 1 30 parts by mass

[Preparation of Masterbatches 2 to 5]
According to the formulations in Table 1, the raw materials were melt-blended in the same manner as for Masterbatch 1 to obtain Masterbatches 2 to 5 (MB2 to 5).

Example 1
[Preparation of Gas Adsorption Layer Resin Composition]
MB1 and high heat-resistant, low odor resin 1 were dry-blended in the following ratio to obtain gas adsorption layer resin composition 1.
MB1 5.6 parts by mass High heat resistant, low odor resin 1 94.4 parts by mass [Preparation of high heat resistant, low odor gas adsorption sealant film]
Using the gas adsorbing layer resin composition 1 and the high heat resistance, low odor resin 1 obtained above, a high heat resistance, low odor gas adsorbing sealant film 1 having the following layer structure was obtained by an inflation method.
The obtained highly heat-resistant, low odor, gas-adsorbing sealant film 1 was used to evaluate film formability.
Layer structure of high heat resistant, low odor gas adsorption sealant film 1: Heat seal layer 1/gas adsorption layer/heat seal layer 2 = high heat resistant low odor resin 1 (10 μm thick)/gas adsorption layer resin composition 1 (30 μm thick)/high heat resistant, low odor resin 1 (10 μm thick)

[Preparation of Highly Heat-Resistant, Low-Odor Gas-Adsorbing Laminate]
Next, the high heat resistance, low odor gas adsorption sealant film 1 obtained above, the base film 1, and the aluminum foil 1 were bonded together by dry lamination using DL adhesive 1 (dry application amount: 3.5 g/ ^m2 , drying temperature: 70°C) to obtain a high heat resistance, low odor gas adsorption laminate 1 having the following layer structure.
Configuration of high heat-resistant, low odor gas-adsorbing laminate 1: gas barrier substrate layer [substrate layer/adhesive layer/gas barrier layer]/adhesive layer/heat-resistant, low odor gas-adsorbing sealant layer [heat-seal layer 1/gas-adsorbing layer/heat-sealing layer 2] = gas barrier substrate layer [substrate film 1 (12 μm thick)/DL adhesive 1 (3.5 g/m ² )/aluminum foil 1 (7 μm thick)]/DL adhesive 1 (3.5 g/m ² )/heat-resistant, low odor gas-adsorbing sealant film 1 [high heat-resistant, low odor resin 1 (10 μm thick)/gas-adsorbing layer resin composition 1 (30 μm thick)/high heat-resistant, low odor resin 1 (10 μm thick)]
The obtained highly heat-resistant, low-odor gas adsorption laminate 1 was subjected to various evaluations.

<Examples 2 to 10, Comparative Examples 1 to 4>
Using the raw materials shown in Tables 2 to 4, the same procedures as in Example 1 were carried out to obtain a highly heat-resistant, low-odor, gas-adsorbing sealant film and a highly heat-resistant, low-odor, gas-adsorbing laminate, which were then evaluated in the same manner.

<Evaluation method>
[Film forming property]
The appearance of the highly heat-resistant, low-odor, gas-adsorbing sealant film and the highly heat-resistant, low-odor, gas-adsorbing laminate was observed and evaluated sensorily. The evaluation criteria were as follows:
○: Film formation is possible without wrinkles or bumps.
×: Numerous wrinkles and bumps occur, making film formation difficult.

[Heat sealability]
The highly heat-resistant, low-odor gas-adsorbing laminate was cut into 10 cm x 10 cm pieces, and two pieces were overlapped with the highly heat-resistant, low-odor gas-adsorbing sealant layer surfaces facing each other. Using a heat seal tester (TP-701-A manufactured by Tester Sangyo Co., Ltd.), a 1 cm x 10 cm 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 the edges were bifurcated.
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: 160°C
Pressure: 1 kgf/ ^cm2
Time: 1 second Test conditions Test speed: 300 mm/min Load range: 50 N
Pass/fail criteria: ◯: 30N/15mm or more, passed.
×: Less than 30N/15mm, unacceptable.

[Heat shrinkage after boiling]
A highly heat-resistant, low-odor, gas-adsorbing sealant film cut to a size of 10 cm x 10 cm was boiled in hot water at 90 to 100°C for 10 minutes, and the average shrinkage rate of each side after boiling was calculated and judged as pass or fail based on the following criteria.
Good: Heat shrinkage rate is 10% or less. Passed.
×: The heat shrinkage rate is more than 10%, or the film is welded and measurement is impossible.

[With or without yuzu skin after boiling]
The highly heat-resistant, low-odor gas-adsorbing laminate cut into a 10 cm x 10 cm piece was boiled in hot water at 90 to 100°C for 10 minutes, and the appearance was visually inspected to see if any orange peel had developed.
〇: No yuzu skin, passed.
×: Yuzu peel, fail

[Elutable TOC concentration]
A gas sampling bag (GL Sciences, SMART BAG) was filled with the following size of high heat resistance, low odor gas adsorption laminate and water, sealed, boiled at 90°C for 30 minutes, cooled to room temperature, and stored at 35°C for 2 weeks. The TOC concentration of the filled water was then measured to determine the increase in TOC concentration.
Highly heat-resistant, low-odor gas adsorption laminate Size: 15 cm x 44 cm x 50 μm thick x 2 sheets Filling water: Distilled water for high-performance liquid chromatography manufactured by Junsei Chemical Co., Ltd. 1000 g
TOC concentration measuring device: TOC-L total organic carbon meter manufactured by Shimadzu Corporation.
Next, the concentration of elutable TOC contained in the highly heat-resistant, low-odor gas adsorbent laminate was calculated from the increased concentration of TOC in the filling water obtained above using the following formula.
C = X × W1/W2
= X × W1 / (6.6 × S)
C: concentration of elutable TOC contained in the highly heat-resistant, low-odor gas adsorption laminate [ppm]
X: Increased concentration of TOC in the filling water [ppm]
W1: Filled water weight = 1000 [g]
W2: Weight of highly heat-resistant, low-odor gas-adsorbing laminate = 15 x 44 x 50 x 10 ^-4 x 2 x S = 6.6 x S [g]
S: density of the highly heat-resistant, low-odor gas-adsorbing laminate [g/cm ³ ]

[Sensory evaluation of odor and taste]
A pouch (external dimensions: 13 cm x 17 cm) made from a gas sampling bag (GL Sciences, SMART BAG) was filled with two sheets of the highly heat-resistant, low-odor gas-adsorbing laminate cut to 11 cm x 15 cm and 100 ml of water (Japanese natural mineral water, Suntory) as filling water to prepare a liquid package. The liquid package was boiled at 90°C for 30 minutes, and then stored at room temperature for one week, after which a sensory evaluation of the odor and taste of the filled water was conducted.
The evaluation indicators are as follows:
1: Strong odor 2: Odor slightly reduced 3: Odor significantly reduced 4: Same as natural water before filling

<Summary of results>
The highly heat-resistant, low-odor gas-adsorbing laminates of the present invention in all examples showed good film-forming properties, heat-sealing properties, low heat shrinkage after boiling, surface condition after boiling, low eluted TOC concentration, and odor/taste sensory evaluation results.
However, Comparative Examples 1 to 3, which contained an insufficient amount of high heat resistance and low odor resin, showed poor results in any of the properties of film-forming property, heat sealability, low heat shrinkage after boiling, surface condition after boiling, low extractable TOC concentration, and odor/taste sensory evaluation results.
Furthermore, Comparative Example 4, in which the content of the gas adsorbent in the gas adsorption layer was too high, showed good gas adsorption effect, but showed poor results in film formability and heat sealing.

1 High heat resistant, low odor gas adsorption laminate 2 High heat resistant, low odor gas adsorption packaging material 3 High heat resistant, low odor gas adsorption sealant film 4a Gas adsorption layer 4b Gas adsorbent 4c Heat seal layer 7 Gas barrier substrate layer 8 High heat resistant, low odor gas adsorption sealant layer 9 Adhesive layer

Claims (9)

A highly heat-resistant, low-odor, gas-adsorbing laminate having a gas barrier substrate layer, an adhesive layer, and a highly heat-resistant, low-odor, gas-adsorbing sealant layer in this order ,
The gas barrier substrate layer has a substrate layer made of a resin film and a gas barrier layer,
the gas barrier layer comprises one or a combination of two or more selected from the group consisting of a metal foil, a metal vapor-deposited film, and a metal oxide vapor-deposited film;
The adhesive forming the adhesive layer is a thermosetting, ultraviolet-curing, or electron beam-curing type (excluding cases where the adhesive layer contains a deodorizing agent) .
The high heat resistant, low odor gas adsorption sealant layer contains a high heat resistant, low odor resin having heat sealing properties and a gas adsorbent, and adsorbs gases generated from the high heat resistant, low odor gas adsorption sealant layer itself and gases from the outside of the high heat resistant, low odor gas adsorption sealant layer (excluding the case where the high heat resistant, low odor gas adsorption sealant layer contains a slip agent and an antiblocking agent as a friction resistance reducing agent).
the gas is one or a combination of two or more selected from the group consisting of hydrocarbons, aldehydes, ketones, and carboxylic acids;
The density of the high heat resistance and low odor resin is 0.920 g/cm ^{or more} and 0.960 g/cm or ^less ,
The film made of the highly heat-resistant, low-odor resin has a concentration of leachable total organic carbon (TOC) of 1.5 ppm or more and 250 ppm or less, and is leachable by boiling at 90 to 110°C for 30 minutes and by storing the film at 35°C.
The heat shrinkage rate when boiled at a temperature of 90°C or higher and 100°C or lower for 10 minutes or longer and 60 minutes or shorter is 0% or higher and 10% or lower, and no orange peel-like change occurs on the surface.
The highly heat-resistant, low-odor gas-adsorbing laminate. the high heat resistance, low odor gas adsorption sealant layer contains a resin of 70 mass % or more and 100 mass % or less, the high heat resistance, low odor resin;
The gas adsorbent is contained in a layer containing the gas adsorbent in an amount of 0.1 mass% or more and 30 mass% or less.
The highly heat-resistant, low-odor gas-adsorbing laminate according to claim 1 . The highly heat-resistant, low-odor gas adsorption laminate described in claim 1 or 2, characterized in that the highly heat-resistant, low-odor resin is a polyethylene-based resin. The highly heat-resistant, low-odor gas adsorption laminate according to any one of claims 1 to 3, characterized in that the highly heat-resistant, low-odor resin is one or a combination of two or more selected from the group consisting of high-density polyethylene, medium-density polyethylene, low-density polyethylene, and linear low-density polyethylene. The highly heat-resistant, low-odor gas adsorption laminate according to any one of claims 1 to 4, characterized in that the gas adsorbent comprises one or a combination of two or more selected from the group consisting of hydrophobic zeolite, molecular sieve, metal-organic framework (MOF), and activated carbon. the highly heat-resistant, low-odor, gas-adsorbing sealant layer has a gas-adsorbing layer and a heat-sealing layer;
the gas adsorption layer is a layer containing the high heat-resistant, low odor resin and the gas adsorbent,
the heat seal layer contains the highly heat-resistant, low-odor resin and has heat sealability;
At least the outermost layer of the highly heat-resistant, low-odor, gas-adsorbing sealant layer is a heat seal layer,
The high heat resistant, low odor resin contained in the gas adsorption layer and the high heat resistant, low odor resin contained in the heat seal layer are the same or different.
The highly heat-resistant, low-odor gas-adsorbing laminate according to any one of claims 1 to 5. A highly heat-resistant, low-outgassing, gas-adsorbing packaging material made using the highly heat-resistant, low-odor, gas-adsorbing laminate described in any one of claims 1 to 6. A highly heat-resistant, low-gas-emission gas-adsorbing packaging material for boiling sterilization or semi-retort sterilization, made using the highly heat-resistant, low-odor, gas-adsorbing laminate described in any one of claims 1 to 6. A highly heat-resistant, low-outgassing, gas-adsorbing packaging body made using the highly heat-resistant, low-outgassing, gas-adsorbing packaging material described in claim 7 or 8.