JP7615224B2 - Hydrogen Sulfide Absorption Film - Google Patents

Description

The present invention relates to a gas absorbing film.

Conventionally, in the fields of food, medicine, electronic parts, precision machinery, recording materials, etc., gas absorbents have been included in the package to prevent quality deterioration. In addition, in order to give the packaging material itself the gas absorption function without putting a separate gas absorbent inside the package, the absorbent is contained in the packaging material itself.

Specifically, Patent Document 1 discloses an oxygen-absorbing packaging material that is characterized by being made up of a polyolefin inner surface, an oxygen-absorbing layer made of a composition of polyolefin and an iron-based oxygen absorber, a polyolefin buffer layer, aluminum foil, and a stretched film or an inorganic vapor-deposited plastic film laminated in that order.

As a packaging material for absorbing sulfide-based gases such as hydrogen sulfide and mercaptan, Patent Document 2 discloses a laminate for absorbing sulfide-based gases, which has a first skin layer containing an olefin-based elastomer and an adsorption layer containing an inorganic adsorbent that adsorbs sulfides and a binder.

As mentioned in this Patent Document 2, it is known to use, as an inorganic adsorbent for adsorbing sulfides, a metal-based chemical absorbent, for example, a compound or salt containing at least one metal selected from copper, iron, zinc, manganese, cobalt, nickel, zirconium, and lanthanoid elements.

JP 2000-343661 A JP 2016-112510 A

Depending on the application, packaging materials using gas absorbing films may be required to have heat resistance that allows them to maintain their shape for long periods in high-temperature environments in addition to gas absorption. In this case, it is preferable to use polypropylene-based resins, which are easy to form into films and have excellent heat resistance. However, the inventors have found that when a gas absorbing film is made using a polypropylene-based resin and a metal-based chemical absorbent and placed in a high-temperature environment, the gas absorbing film becomes brittle in a short period of time, and the heat resistance of polypropylene may not be fully utilized.

Therefore, there is a need to provide a gas absorbing film that contains a metal-based chemical absorbent and is resistant to embrittlement in high temperature environments.

As a result of intensive research, the present inventors have found that the above problems can be solved by the following means, and have completed the present invention. That is, the present invention is as follows:
<Aspect 1> A gas absorbing layer and a first heat resistant layer are provided,
The gas absorbing layer contains an olefin-based thermoplastic resin other than a polypropylene-based resin, and a metal-based chemical absorbent dispersed in the thermoplastic resin, and the first heat-resistant layer is made of a polypropylene-based resin.
Gas absorbing film.
<Aspect 2> The gas absorbing film according to aspect 1, wherein the thermoplastic resin of the gas absorbing layer is a polyethylene-based resin.
<Aspect 3> The gas absorbing film according to aspect 2, wherein the polyethylene resin of the gas absorbing layer is a copolymer of ethylene and an ethylene monomer having a carboxyl group or an ester group.
Aspect 4: The gas absorbing film according to aspect 3, wherein the copolymer of the gas absorbing layer is an ethylene-acrylic acid copolymer, an ethylene-methacrylic acid copolymer, an ethylene-ethyl acrylate copolymer, an ethylene-methyl acrylate copolymer, or an ethylene-vinyl acetate copolymer.
<Aspect 5> The gas absorbing film according to any one of aspects 1 to 4, wherein the metal-based chemical absorbent contains at least one selected from the group consisting of copper, cobalt, manganese, iron, nickel, zinc, silver, calcium, and titanium.
<Aspect 6> The gas absorbing film according to any one of Aspects 1 to 5, further comprising a first buffer layer between the gas absorbing layer and the first heat-resistant layer, the first buffer layer being made of an olefin-based thermoplastic resin other than a polypropylene-based resin.
<Aspect 7> The gas absorbing film according to aspect 6, wherein the thermoplastic resin of the first buffer layer is a polyethylene-based resin.
<Aspect 8> The gas absorbing film according to aspect 7, wherein the polyethylene resin of the first buffer layer is a copolymer of ethylene and an ethylene monomer having a carboxyl group or an ester group.
Aspect 9: The gas absorbing film according to aspect 8, wherein the copolymer of the first buffer layer is an ethylene-acrylic acid copolymer, an ethylene-methacrylic acid copolymer, an ethylene-ethyl acrylate copolymer, an ethylene-methyl acrylate copolymer, or an ethylene-vinyl acetate copolymer.
<Embodiment 10> The gas absorbing film according to any one of embodiments 1 to 9, further comprising a second heat-resistant layer on the side of the gas absorbing layer opposite the first heat-resistant layer.
<Aspect 11> The gas absorbing film according to aspect 10, further comprising a second buffer layer between the gas absorbing layer and the second heat-resistant layer, the second buffer layer being made of an olefin-based thermoplastic resin other than a polypropylene-based resin.
A gas absorbing film according to any one of Aspects 1 to 11, and a substrate layer, the substrate layer being laminated on a side of the gas absorbing layer opposite to the first heat-resistant layer.
Packaging laminates.
<Aspect 13> The packaging laminate according to aspect 12, wherein the base material layer has a barrier layer and a base material resin layer, and further comprises a base material resin layer on the side of the barrier layer opposite the gas absorbing layer.
A packaging laminate according to claim 12 or 13, wherein a part of the first heat-resistant layer side of the packaging laminate is heat-sealed to another part of the packaging laminate or another film to form a bag.
Packaging bag.

The present invention provides a gas absorbing film that contains a metal-based chemical absorbent and is resistant to embrittlement in high-temperature environments.

FIG. 1 is a cross-sectional side view of a gas absorbing film of the present invention. FIG. 2 is a cross-sectional side view of the packaging laminate of the present invention.

Gas absorbing film
As shown in FIG. 1(a), the gas absorbing film 10a of the present invention has the following features:
The gas absorbing layer 12 and the first heat resistant layer 14 are included.
The gas absorbing layer 12 contains an olefin-based thermoplastic resin other than a polypropylene-based resin, and a metal-based chemical absorbent dispersed in the thermoplastic resin, and the first heat-resistant layer 14 is composed of a polypropylene-based resin.

The inventors have found that embrittlement of the film is accelerated by placing the film in a high-temperature environment in the presence of oxygen while the polypropylene resin and the metal-based chemical absorbent are in contact with each other. Without wishing to be bound by theory, this is believed to be due to the metal-based chemical absorbent acting as a catalyst to promote the reaction between the easily oxidized polypropylene resin and oxygen, and the high-temperature environment. In response to this problem, the inventors have found that the embrittlement of the film can be suppressed by preventing contact between the polypropylene resin and the metal-based chemical absorbent through the above-mentioned configuration.

The gas absorbing film of the present invention can therefore be used in environments where high temperatures, for example, temperatures of 50°C or higher, 60°C or higher, 70°C or higher, 80°C or higher, or 90°C or higher, and temperatures of 150°C or lower, 140°C or lower, 130°C or lower, 120°C or lower, or 110°C or lower can be reached. The gas absorbing film of the present invention can therefore be used, for example, for packaging all-solid-state lithium ion batteries.

The gas absorbing film of the present invention can absorb various gases, and can be a hydrogen sulfide absorbing film that absorbs hydrogen sulfide particularly well.

In one embodiment of the present invention, as shown in FIG. 1(b), the gas absorbing film 10b of the present invention further comprises a first buffer layer 16 composed of an olefin-based thermoplastic resin other than a polypropylene-based resin between the gas absorbing layer 12 and the first heat-resistant layer 14. This configuration is preferable from the viewpoint of further suppressing embrittlement of the gas absorbing film.

In one embodiment of the present invention, as shown in FIG. 1(c), the gas absorbing film 10c of the present invention further comprises a second heat-resistant layer 14' on the side of the gas absorbing layer 12 opposite to the first heat-resistant layer 14. In this case, as shown in FIG. 1(d), the gas absorbing film 10d of the present invention may further comprise a second buffer layer 16' composed of an olefin-based thermoplastic resin other than a polypropylene-based resin between the gas absorbing layer 12 and the second heat-resistant layer 14'.

In any of the above embodiments, the layers constituting the gas absorbing film may be laminated directly to each other, and in particular may be fused together.

Each component of the present invention is described below.

<Gas absorbing layer>
The gas absorbing layer contains an olefin-based thermoplastic resin other than a polypropylene-based resin, and a metal-based chemical absorbent dispersed in the thermoplastic resin.

The content of the metal-based chemical absorbent in the gas absorbing layer is preferably 1 mass% or more, 3 mass% or more, 5 mass% or more, 7 mass% or more, or 10 mass% or more based on the mass of the entire gas absorbing layer from the viewpoint of ensuring good absorption capacity, and is preferably 70 mass% or less, 65 mass% or less, 60 mass% or less, 55 mass% or less, or 50 mass% or less from the viewpoint of ensuring good film formability.

The thickness of the gas absorbing layer is preferably 1 μm or more, 2 μm or more, 3 μm or more, 5 μm or more, 10 μm or more, 20 μm or more, or 30 μm or more in terms of ensuring good absorption capacity, and is preferably 100 μm or less, 90 μm or less, or 80 μm or less in terms of ensuring the flexibility of the film.

(Olefin-based thermoplastic resin)
The olefin-based thermoplastic resin is an olefin-based thermoplastic resin other than a polypropylene-based resin. An example of the olefin-based thermoplastic resin is a polyethylene-based resin. Although the polyethylene-based resin has poor heat resistance, it is preferable because it has excellent processability.

In this specification, a polyethylene-based resin is a resin that contains more than 50 mol%, 60 mol% or more, 70 mol% or more, or 80 mol% or more of repeating ethylene groups in the main chain of the polymer. As such a polyethylene-based resin, polyethylene such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), etc. may be used, or a copolymer of ethylene and an ethylene-based monomer having a carboxyl group or an ester group may be used.

Examples of the copolymer that can be used include ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate copolymer (EMA), ethylene-methyl methacrylate copolymer (EMMA), and ethylene-vinyl acetate copolymer (EVA).

The thermal properties of the above-mentioned olefin-based thermoplastic resin, for example, when its melt mass flow rate is measured in accordance with JIS K6922-1 using polyethylene conditions, may be preferably 0.1 g/10 min or more, 0.5 g/10 min or more, 1.0 g/10 min or more, 3.0 g/10 min or more, or 5.0 g/10 min or more, and may be 200 g/10 min or less, 100 g/10 min or less, 50 g/10 min or less, or 30 g/10 min or less. For example, when the melt mass flow rate is measured in accordance with JIS K7210 using polypropylene conditions, it is preferably 0.1 g/10 min or more, 0.5 g/10 min or more, 1.0 g or more, 3.0 g/10 min or more, 5.0 g/10 min or more, or 10 g/10 min or more, and may be 200 g/10 min or less, 100 g/10 min or less, 50 g/10 min or less, or 30 g/10 min or less.

(Metal-based chemical absorbents)
The metal-based chemical absorbent may contain at least one selected from the group consisting of copper, cobalt, manganese, iron, nickel, zinc, silver, calcium, and titanium, and may be in the form of a simple substance or a compound thereof, particularly a salt thereof, and more particularly a silicate thereof.

Particularly preferred metal-based chemical absorbents are metal silicates containing at least one metal selected from copper, zinc, manganese, cobalt, and nickel, and more preferably have an elemental composition (molar) ratio of metal to silicon in the range of metal/silicon = 0.60 to 0.80. Such inorganic adsorbents can be produced by reacting a metal salt with an alkali silicate. As the metal salt, inorganic salts such as sulfuric acid, hydrochloric acid, and nitric acid, and/or organic salts such as formic acid, acetic acid, and oxalic acid, of at least one metal selected from copper, zinc, manganese, cobalt, and nickel can be used. Among these, preferred metals are copper (I), copper (II), and zinc (I). As the silicate, an alkali silicate of the formula M ₂ O.nSiO _{2.xH 2} O (wherein M represents a monovalent alkali metal, n is 1 or more, and x is 0 or more) can be mentioned. The most preferred metal silicate is copper(II) silicate, which is a reaction product of copper(II) sulfate and sodium silicate, and is described, for example, in JP 2011-104274 A. For example, a copper(II) silicate-based adsorbent available from Toagosei Co., Ltd. under the name Kesmon NS-20C can be used. In particular, when this metal-based chemical absorbent is used, hydrogen sulfide can be absorbed well, as mentioned in Patent Document 2.

<First heat-resistant layer>
The first heat-resistant layer is a layer made of a polypropylene-based resin. By providing the first heat-resistant layer separately from the gas absorbing layer, direct contact between the polypropylene-based resin and the metal-based chemical absorbent can be suppressed, and as a result, embrittlement of the gas absorbing film can be suppressed.

(Polypropylene resin)
In this specification, a polypropylene-based resin is a resin containing more than 50 mol%, 60 mol% or more, 70 mol% or more, or 80 mol% or more of repeating units of propylene groups in the main chain of the polymer. Examples of such polypropylene-based resins include polypropylene (PP) homopolymer, random polypropylene (random PP), block polypropylene (block PP), chlorinated polypropylene, carboxylic acid-modified polypropylene, and derivatives thereof, and mixtures thereof.

The first buffer layer
The first buffer layer is a layer made of an olefin-based thermoplastic resin other than a polypropylene-based resin. By providing such a first buffer layer between the heat-resistant layer and the absorbing layer, direct contact between the metal-based chemical absorbent and the polypropylene-based resin can be prevented, and as a result, embrittlement of the gas absorbing film can be further suppressed.

As the thermoplastic resin, for example, the olefin-based thermoplastic resins mentioned in relation to the gas absorbing layer can be used.

<Second heat-resistant layer>
The second heat-resistant layer is a layer composed of a polypropylene-based resin. The polypropylene-based resin constituting the second heat-resistant layer and the thickness of the second heat-resistant layer may be the same as or different from those of the first heat-resistant layer.

The second buffer layer
The second buffer layer is a layer composed of an olefin-based thermoplastic resin other than a polypropylene-based resin. The thermoplastic resin constituting the second buffer layer and the thickness of the second buffer layer may be the same as or different from those of the first buffer layer.

<<Method for manufacturing gas absorbing film>>
The gas absorbing film of the present invention can be produced by melt-kneading the materials constituting each layer of the gas absorbing film as necessary, forming the films, and laminating the layers.

Melt mixing can be carried out using, for example, a batch mixer such as a kneader, a Henschel mixer, or a mixing roll, or a continuous mixer such as a twin-screw mixer.

Film formation can be carried out, for example, by the inflation method, T-die method, calendar method, casting method, heat press molding, extrusion molding, or injection molding.

Lamination can be performed by extrusion lamination methods such as sand lamination, heat sealing, heat press molding, etc.

Also, film formation and lamination may be performed simultaneously by coextrusion methods such as the coextrusion inflation method and the coextrusion T-die method.

<<Packaging laminate>>
As shown in FIG. 2, the packaging laminates 100a and 100b of the present invention are
The gas absorbing film 10 a , 10 d and the substrate layer 20 are included, and the substrate layer 20 is laminated on the gas absorbing layer 12 on the side opposite to the first heat-resistant layer 14 .

Here, "the base layer is laminated on the side of the gas absorbing layer opposite the first heat-resistant layer" means that the base layer, gas absorbing layer, and first heat-resistant layer are present in this order in the layer configuration of the packaging laminate, and other layers may or may not be present between these layers. For example, as shown in FIG. 2(a), the base layer 20, gas absorbing layer 12, and first heat-resistant layer 14 may be laminated directly in this order.

Also, as shown in FIG. 2(b), the base layer 20, the gas absorbing layer 12, and the first heat-resistant layer 14 may be indirectly laminated in this order. Specifically, the base layer may be laminated to the gas absorbing layer via the second heat-resistant layer and/or the second buffer layer, and/or the first heat-resistant layer may be laminated to the gas absorbing layer via the first buffer layer.

In any of the above embodiments, as shown in FIG. 2, the substrate layer 20 may have a barrier layer 22 and a substrate resin layer 24.

The lamination of the base layer and the gas absorbing film, and the lamination of the following layers that can constitute the base layer, can be performed, for example, via an adhesive layer. As the adhesive layer, for example, a dry lamination adhesive, an anchor coat adhesive, a hot melt adhesive, a water-soluble adhesive, an emulsion adhesive, a non-solvent lamination adhesive, and a thermoplastic resin for extrusion lamination can be used.

The packaging laminate of the present invention can be used for various packaging applications, for example, as a laminate film for all-solid-state batteries.

<Base layer>
The substrate layer may have a barrier property, and may include a barrier layer and a substrate resin layer.

(Barrier Layer)
The barrier layer may be made of a material capable of suppressing the permeation of moisture, organic gases, and inorganic gases such as oxygen from the outside into the gas absorbing layer. The barrier layer may be made of, but is not limited to, a metal foil such as an aluminum foil or an aluminum alloy, an inorganic vapor deposition film such as an aluminum vapor deposition film, a silica vapor deposition film, an alumina vapor deposition film, or a silica-alumina binary vapor deposition film, or an organic coating film such as a polyvinylidene chloride coating film or a polyvinylidene fluoride coating film. In particular, from the viewpoint of easily achieving both barrier properties and ease of handling, it is preferable to use an aluminum foil as the barrier layer.

The thickness of the barrier layer is preferably 7 μm or more, 10 μm or more, or 15 μm or more from the viewpoint of ensuring strength and barrier properties, and is preferably 45 μm or less, 40 μm or less, or 35 μm or less from the viewpoint of improving handleability.

(Base resin layer)
As the base resin layer, a thermoplastic resin having excellent impact resistance, abrasion resistance, etc., such as polyolefin, vinyl polymer, polyester, polyamide, etc., can be used alone or in a multi-layer structure of two or more types. This base resin layer may be a stretched film or a non-stretched film. In addition, this base resin layer may be present on one or both sides of the barrier layer. This base resin layer can protect the barrier layer.

Examples of polyolefins include polyethylene-based resins and polypropylene-based resins. As the polyethylene-based resins, the polyethylene-based resins listed for the gas absorbing layer can be used, and as the polypropylene-based resins, the polypropylene-based resins listed for the first heat-resistant layer can be used.

Examples of vinyl polymers include polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), polychlorotrifluoroethylene, polytetrafluoroethylene, polyacrylonitrile (PAN), etc.

Examples of polyester include polyethylene terephthalate (PET) and polybutylene terephthalate.

Examples of polyamides include nylons such as Nylon (registered trademark) 6 and Nylon MXD6.

The thickness of the base resin layer is preferably 7 μm or more, 10 μm or more, or 15 μm or more from the viewpoint of providing good protection for the barrier layer, and is preferably 55 μm or less, 50 μm or less, or 45 μm or less from the viewpoint of improving handleability.

Packaging Bags
The packaging bag of the present invention comprises one or more of the above-mentioned packaging laminates, and is formed into a bag shape by heat-sealing a part of the first heat-resistant layer side of the one or more packaging laminates to another part of the packaging laminate or another film. Here, the other film may be another packaging laminate or may be a film other than the packaging laminate.

The packaging bag of the present invention can be a content-containing packaging bag that contains the contents.

<Contents>
The contents are not limited as long as they are items that can deteriorate when exposed to outside air, and examples of the contents include medicines, food, cosmetics, medical instruments, medical equipment, electronic parts, precision machinery, recording materials, etc. Furthermore, medicines include pharmaceutical preparations, cleaning agents, agricultural chemicals, etc.

In particular, when the contents are electronic components, particularly all-solid-state lithium-ion batteries that use a sulfide-based solid electrolyte, the packaging bag of the present invention is particularly useful because it requires heat resistance to withstand heat generated during use and the ability to process hydrogen sulfide generated by the sulfide-based solid electrolyte.

The present invention will be specifically explained using examples and comparative examples, but the present invention is not limited to these.

<<Preparation of gas absorbing film>>
Comparative Example 1-1
(Preparation of gas absorbing layer sheet)
90 parts by mass of polypropylene (Novatec FL02A, Japan Polypropylene Corporation) as a thermoplastic resin and 10 parts by mass of a copper (II) silicate adsorbent (Kesmon NS-20C, Toagosei Co., Ltd.) as a gas absorbent were kneaded in a Banbury mixer, cut into pieces of a predetermined mass, and hot-press molded (press temperature 190° C., pressure 60 MPa, press time 2 minutes) to produce a gas absorbent layer sheet having a thickness of 60 μm.

(Preparation of heat-resistant layer sheet)
A predetermined mass of polypropylene (Novatec FL02A, Japan Polypropylene Corporation) was weighed out and subjected to hot press molding (press temperature 190° C., pressure 60 MPa, press time 5 minutes) to produce a sheet for a heat-resistant layer having a thickness of 30 μm.

(Preparation of Gas Absorbing Film)
A heat-resistant layer sheet was superimposed on each side of the prepared gas absorbing layer sheet, and the resultant was hot-press molded (press temperature 150° C., pressure 10 MPa, press time 10 seconds) to prepare a gas absorbing film of Comparative Example 1-1.

Comparative Examples 1-2 to 1-3 and Examples 1-1 to 1-9
The gas absorbing films of Comparative Examples 1-2 to 1-3 and Examples 1-1 to 1-9 were produced in the same manner as in Comparative Example 1-1, except that the type and content of the thermoplastic resin in the gas absorbing layer was changed as shown in Table 1 and the heat press temperature was adjusted within the range of 150 to 190°C depending on the melting point of the thermoplastic resin used.

As the thermoplastic resin for the gas absorbing layer, the following resin was used:
Low density polyethylene (LDPE): Petrothene 202R (Tosoh Corporation, MFR 5.0 g/10 min)
Ethylene-ethyl acrylate copolymer (EEA): Rexpearl (registered trademark) A6200 (Japan Polyethylene Co., Ltd., MF: 20.0 g/10 min)
Ethylene-methyl acrylate copolymer (EMA): Rexpearl EB440H (Japan Polyethylene Co., Ltd., MFR 18.0 g/10 min)
Ethylene-methyl methacrylate copolymer (EMMA): Acryft (registered trademark) WH401-F (Sumitomo Chemical Co., Ltd., MFR 20.0 g/10 min)

Next, we will discuss gas absorbing films with buffer layers.

Example 2-1
A predetermined mass of polypropylene (Novatec FL02A, Japan Polypropylene Corporation) as a thermoplastic resin was weighed out and subjected to hot press molding (press temperature 190°C, pressure 60 MPa, press time 2 minutes) to produce a buffer layer sheet having a thickness of 30 μm.

A gas absorbing film of Example 2-1 was produced in the same manner as in Example 1-1, except that a buffer layer sheet was placed between the gas absorbing layer sheet and each heat-resistant layer sheet, and this was hot-press molded (press temperature 170°C, pressure 20 MPa, press time 1 minute), and the thickness of the heat-resistant layer sheet was set to 60 μm.

<Examples 2-2 to 2-8>
Except for changing the type of thermoplastic resin used in the buffer layer sheet as shown in Table 2, gas absorbing films of Examples 2-2 to 2-8 were produced in the same manner as in Example 2-1.

The following resins are used as the thermoplastic resin for the buffer layer:
Linear low density polyethylene (LLDPE): EVOLUE (registered trademark) SP2520 (Prime Polymer Co., Ltd., MFR 1.9 g/10 min)
Low density polyethylene (LDPE): Petrothene 342 (Tosoh Corporation, MFR 8.0 g/10 min)
Ethylene-ethyl acrylate copolymer (EEA): Rexpearl A4250 (Japan Polyethylene Co., Ltd., MFR 5.0 g/10 min)
Ethylene-methyl acrylate copolymer (EMA): Rexpearl EB140F (Japan Polyethylene Co., Ltd., MFR 2.6 g/10 min)
Ethylene-methacrylic acid copolymer (EMAA): Nucrel AN4221C (Mitsui DuPont Polychemicals Co., Ltd., MFR 10.0 g/10 min)
Ethylene-methyl methacrylate copolymer (EMMA): Acryft (registered trademark) WH206-F (Sumitomo Chemical Co., Ltd., MFR 2.0 g/10 min)
Ethylene-vinyl acetate copolymer (EVA): Ultrathene 625 (Tosoh Corporation, MFR 14.0 g/10 min)

Embrittlement test
The gas absorbing film thus produced was placed in an oven at 100° C., and the film was taken out at predetermined intervals and bent 180° to check for the presence or absence of cracks or breakage. In Tables 1 and 2, the evaluation criteria are shown below according to the time until cracks or breakage occur:
A: 30 days or more B: 17 days or more but less than 30 days C: 12 days or more but less than 17 days D: 7 days or more but less than 12 days E: Less than 7 days

The gas absorbing films of Comparative Examples 1-1 to 1-3 and Examples 1-1 to 1-9 were subjected to the same test using an oven at 120° C. In Tables 1 and 2, the evaluation criteria are shown below according to the time until cracks and fractures occur:
A: 3 days or more B: 1 day or more but less than 3 days C: 0.5 days or more but less than 1 day D: Less than 0.5 days

The configurations and evaluation results of the examples and comparative examples are shown in Tables 1 and 2.

From Table 1, it can be seen that the gas absorbing films of Examples 1-1 to 1-9, which use a polyethylene-based resin as the thermoplastic resin of the gas absorbing layer, can effectively suppress cracks and breaks in the film compared to the gas absorbing films of Comparative Examples 1-1 to 1-3, which use a polypropylene-based resin. In particular, when the film is heated at 100°C, it can be seen that the gas absorbing films of Examples 1-1 to 1-3, which use polyethylene as the thermoplastic resin of the gas absorbing layer, can effectively suppress cracks and breaks in the film. In addition, it can be seen that when the film is heated at 120°C, the gas absorbing films of Examples 1-4 to 1-9, which use a copolymer of ethylene and an ethylene-based monomer having a carboxyl group or an ester group as the thermoplastic resin of the gas absorbing layer, can effectively suppress cracks and breaks in the film.

It can also be seen from Table 2 that the gas absorbing films of Examples 2-2 to 2-8, which use a polyethylene-based resin as the thermoplastic resin in the buffer layer, can effectively suppress cracks and breaks in the film, compared to the gas absorbing film of Example 1-1, which does not use a buffer layer, and the gas absorbing film of Example 2-1, which uses a polypropylene-based resin as the buffer layer. In particular, it can be seen that the gas absorbing films of Examples 2-4 to 2-8, which use a copolymer of ethylene and an ethylene-based monomer having a carboxyl group or an ester group as the thermoplastic resin in the buffer layer, can effectively suppress cracks and breaks in the film.

REFERENCE SIGNS LIST 10a, 10b, 10c, 10d Gas absorbing film 12 Gas absorbing layer 14 First heat resistant layer 14' Second heat resistant layer 16 First buffer layer 16' Second buffer layer 20 Base material layer 22 Barrier layer 24 Base material resin layer 100a, 100b Packaging laminate

Claims (12)

A hydrogen sulfide absorbing film, comprising:
The insulating film has a first heat-resistant layer, a gas-absorbing layer, and a second heat-resistant layer in this order ,
the gas absorbing layer contains a polyethylene-based resin and a metal-based chemical absorbent dispersed in the polyethylene-based resin; and the first and second heat-resistant layers are made of a polypropylene-based resin;
the polyethylene resin of the gas absorbing layer is a copolymer of ethylene and an ethylene monomer having a carboxyl group or an ester group, and the layers constituting the hydrogen sulfide absorbing film are fused to each other;
Hydrogen sulfide absorbing film. The hydrogen sulfide absorbing film according to claim 1, wherein the copolymer of the gas absorbing layer is an ethylene-acrylic acid copolymer, an ethylene-methacrylic acid copolymer, an ethylene-ethyl acrylate copolymer, an ethylene-methyl acrylate copolymer, or an ethylene-vinyl acetate copolymer. A hydrogen sulfide absorbing film, comprising:
The insulating film has a first heat-resistant layer, a first buffer layer, a gas absorbing layer, and a second heat-resistant layer in this order,
the gas absorbing layer contains an olefin-based thermoplastic resin other than a polypropylene-based resin, and a metal-based chemical absorbent dispersed in the olefin-based thermoplastic resin; and the first and second heat-resistant layers are made of a polypropylene-based resin;
The first buffer layer is composed of a copolymer of ethylene and an ethylene-based monomer having a carboxyl group or an ester group, and each layer constituting the hydrogen sulfide absorbing film is fused to each other.
Hydrogen sulfide absorbing film. The hydrogen sulfide absorbing film according to claim 3, wherein the copolymer of the first buffer layer is an ethylene-acrylic acid copolymer, an ethylene-methacrylic acid copolymer, an ethylene-ethyl acrylate copolymer, an ethylene-methyl acrylate copolymer, or an ethylene-vinyl acetate copolymer. The hydrogen sulfide absorbing film according to any one of claims 1 to 4, wherein the metal-based chemical absorbent contains at least one selected from the group consisting of copper, cobalt, manganese, iron, nickel, zinc, silver, calcium, and titanium. The hydrogen sulfide absorbing film according to any one of claims 1 to 5 , further comprising a second buffer layer between the gas absorbing layer and the second heat-resistant layer, the second buffer layer being composed of an olefin-based thermoplastic resin other than a polypropylene-based resin. 7. The hydrogen sulfide absorbing film according to claim 6 , wherein the second buffer layer is composed of a copolymer of ethylene and an ethylene-based monomer having a carboxyl group or an ester group. 8. The hydrogen sulfide absorbing film according to claim 1 , wherein the content of the metal-based chemical absorbent in the gas absorbing layer is 1% by mass or more and 70% by mass or less. A substrate layer and a hydrogen sulfide absorbing film,
the hydrogen sulfide absorbing film comprises a gas absorbing layer and a first heat resistant layer in this order;
the base layer is laminated on the gas absorbing layer on the opposite side to the first heat resistant layer,
The gas absorbing layer contains a polyethylene resin and a metal-based chemical absorbent dispersed in the polyethylene resin; and
The first heat-resistant layer is made of a polypropylene-based resin,
The polyethylene resin of the gas absorbing layer is a copolymer of ethylene and an ethylene monomer having a carboxyl group or an ester group; and
The layers constituting the hydrogen sulfide absorbing film are fused to each other;
Packaging laminates. A substrate layer and a hydrogen sulfide absorbing film,
the hydrogen sulfide absorbing film comprises a gas absorbing layer, a first buffer layer, and a first heat resistant layer in this order;
the base layer is laminated on the gas absorbing layer on the opposite side to the first heat resistant layer,
The gas absorbing layer contains an olefin-based thermoplastic resin other than a polypropylene-based resin, and a metal-based chemical absorbent dispersed in the olefin-based thermoplastic resin; and
The first heat-resistant layer is made of a polypropylene-based resin,
The first buffer layer is composed of a copolymer of ethylene and an ethylene-based monomer having a carboxyl group or an ester group, and
The layers constituting the hydrogen sulfide absorbing film are fused to each other;
Packaging laminates. The packaging laminate according to claim 9 or 10, wherein the substrate layer has a barrier layer and a substrate resin layer, and further comprises a substrate resin layer on the opposite side of the barrier layer to the gas absorbing layer. The packaging laminate according to any one of claims 9 to 11, wherein the packaging laminate is formed into a bag shape by heat-sealing a part of the first heat-resistant layer side of the packaging laminate or the part of the first heat-resistant layer side of the packaging laminate or the part of the first heat-resistant layer side of the packaging laminate or the film.
Packaging bag.

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