JP2021146630A - Moisture absorption and gas absorption laminate film - Google Patents

Abstract

To provide a moisture absorption and gas absorption laminate film which enables checking of discoloration of a gas absorber while having moisture absorption and gas absorption.SOLUTION: A moisture absorption and gas absorption laminate film 10 has a barrier base material layer 12, a transparent moisture absorption layer 14, and a discoloration gas absorption layer 18 in this order or the barrier base material layer 12, the discoloration gas absorption layer 18 and the transparent moisture absorption layer 14 in this order. The transparent moisture absorption layer 14 contains a thermoplastic resin and a moisture absorbent, and the discoloration gas absorption layer 18 absorbs gas and thereby can be discolored.SELECTED DRAWING: Figure 1

Description

The present invention relates to a moisture absorbing and gas absorbing laminated film.

Traditionally, in the fields of foods, pharmaceuticals, medical equipment, medical equipment, electronic parts, precision machinery, recording materials, etc., packaging with water vapor absorption capacity and oxygen absorption capacity has been used to prevent quality deterioration due to moisture and oxygen. Articles are stored and stored in bags, and packaging bags for that purpose have been proposed.

In Patent Document 1, the packaging bag has a heat-sealed portion at an end and is formed into a bag shape by the heat-sealed portion, and the heat-sealed portion has an oxygen absorbing layer, a water vapor absorbing layer, and a barrier layer. However, a packaging bag is disclosed in which the oxygen absorbing layer contains cerium oxide having an oxygen deficiency.

Further, Patent Document 2 describes a film which has extremely high transparency and is useful as a film for encapsulating an organic EL or the like.

Patent Documents 3 and 4 describe methods for producing zeolite having a nano-particle size.

Japanese Unexamined Patent Publication No. 2018-115026 Japanese Unexamined Patent Publication No. 2018-100390 Japanese Unexamined Patent Publication No. 2011-246292 Japanese Unexamined Patent Publication No. 2013-49602

A gas absorbent that discolors due to absorption of gas, for example, cerium oxide having an oxygen deficiency as in Patent Document 1, can determine the presence or absence of inactivation by visually confirming this discoloration. Therefore, there is a need to provide a moisture-absorbing and gas-absorbing laminated film that has hygroscopicity and gas-absorbing property and can confirm discoloration of the gas-absorbing agent.

As a result of diligent studies, 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> The barrier base material layer, the transparent moisture absorbing layer, and the discoloring gas absorbing layer are provided in this order, or the barrier base material layer, the discoloring gas absorbing layer, and the transparent moisture absorbing layer are provided in this order. ,
The transparent hygroscopic layer contains a thermoplastic resin and a hygroscopic agent.
The discolorable gas absorbing layer can be discolored by absorbing the gas.
Moisture-absorbing and gas-absorbing laminated film.
<Aspect 2> The laminated film according to Aspect 1, wherein the thermoplastic resin of the transparent moisture absorbing layer is a polyolefin resin.
<Aspect 3> The laminated film according to Aspect 1 or 2, wherein the hygroscopic agent is zeolite.
<Aspect 4> The laminated film according to Aspect 3, wherein the average particle size D50 of the zeolite of the transparent moisture absorbing layer is 300 nm or less.
<Aspect 5> The laminated film according to any one of aspects 1 to 4, wherein the transparent moisture absorbing layer further contains an ester compound having an HLB value of 5 or less.
<Aspect 6> The laminated film according to any one of aspects 1 to 5, further comprising a transparent skin layer laminated on one side or both sides of the transparent moisture absorbing layer.
<Aspect 7> The laminated film according to any one of aspects 1 to 6, wherein the barrier base material layer is transparent.
<Aspect 8> The laminated film according to any one of aspects 1 to 7, wherein the discoloring gas absorbing layer contains cerium oxide having an oxygen deficiency.
<Aspect 9> One or a plurality of laminated films according to any one of aspects 1 to 8 are provided, and one or a plurality of the laminated films are on the side opposite to the barrier base material layer side. A part of the laminated film is bag-shaped by being heat-sealed with another part of this laminated film or another film.
Packaging bag.
<Aspect 10> The packaging bag according to the ninth aspect, and a packaging bag containing the contents contained in the packaging bag.

According to the hygroscopic and gas-absorbing laminated film of the present invention, discoloration of the gas absorbent can be confirmed while having hygroscopicity and gas absorption.

FIG. 1 is a schematic cross-sectional view of an embodiment of the moisture-absorbing and gas-absorbing laminated film of the present invention.

<< Moisture-absorbing and gas-absorbing laminated film >>
As shown in FIG. 1, the moisture-absorbing and gas-absorbing laminated film 10 of the present invention is
Whether the barrier base material layer 12, the transparent moisture absorbing layer 14, and the discoloring gas absorbing layer 18 are provided in this order (FIG. 1 (a)), or the barrier base material layer 12, the discoloring gas absorbing layer 18, and the transparent The moisture absorbing layer 14 is provided in this order (FIG. 1 (b)).
The transparent moisture absorbing layer 14 contains a thermoplastic resin and a hygroscopic agent.
The discolorable gas absorbing layer 18 can be discolored by absorbing the gas.

Here, in the present invention, "transparent" means that the contents are sufficiently transparent to be visually recognized, and for example, the total light transmittance is 50% or more, 60% or more, and 70%. 75% or more, 80% or more, 85% or more, 90% or more, 95% or more, or 100%, and the haze value is 50% or less, 45% or less, 40% or less, 35% or less, 30%. Hereinafter, it means that it is 25% or less, 20% or less, 15% or less, or 10% or less.

As shown in FIG. 1, the moisture-absorbing and gas-absorbing laminated film 10 of the present invention may further have a transparent skin layer 16 laminated on one side or both sides of the transparent moisture-absorbing layer. Further, the transparent skin layer 16 may be laminated on one side or both sides of the discoloring gas absorbing layer 18.

According to the above configuration, discoloration of the gas absorbent can be confirmed while having hygroscopicity and gas absorption.

Hereinafter, each component of the present invention will be described.

<Barrier base material layer>
The barrier base material layer is a base material having a barrier property. The barrier base material layer may be a single barrier layer, or may be a layer having a barrier layer and a base material resin layer. In this case, an adhesive layer may be present between the barrier layer and the base resin layer. When the barrier base material layer is a transparent barrier base material layer, the discoloration of the discoloring gas absorbing layer is visible from both surfaces of the laminate.

(Barrier layer)
The barrier layer may be a transparent barrier layer or an opaque barrier layer. When the barrier layer is a transparent barrier layer, the barrier base material layer can be a transparent barrier base material layer.

(Barrier layer: Transparent barrier layer)
As the transparent barrier layer, a material that is transparent and capable of suppressing the permeation of moisture, organic gas, and inorganic gas from the outside into the transparent moisture absorbing layer can be used. Examples of the transparent barrier layer include an inorganic vapor deposition film such as a silica vapor deposition film, an alumina vapor deposition film, or a silica-alumina binary vapor deposition film, a polyvinylidene chloride coating film, a polychlorotrifluoroethylene coating film, or a polyvinylidene fluoride coating film. An organic coating film such as a film can be used. Further, the above-mentioned barrier resin layer can also be used as a transparent barrier layer.

When an inorganic vapor-deposited film is used as the transparent barrier layer, the thickness of the transparent barrier layer is 100 nm or more, 200 nm or more, 300 nm or more, 500 nm or more, 700 nm or more, or 1 μm or more from the viewpoint of ensuring strength and barrier properties. Therefore, it is preferably 5 μm or less, 4 μm or less, 3 μm or less, or 2 μm or less from the viewpoint of improving the handleability as a packaging bag.

When a barrier resin layer or an organic coating film is used as the transparent barrier layer, the thickness of the transparent 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. It is preferably 100 μm or less, 80 μm or less, 60 μm or less, 55 μm or less, 50 μm or less, 45 μm or less, 40 μm or less, or 35 μm or less from the viewpoint of improving the handleability as a packaging bag.

(Barrier layer: Opaque barrier layer)
As the opaque barrier layer, for example, a single metal foil layer such as copper foil or aluminum foil, an alloy foil layer such as stainless steel foil, or the like can be used.

The thickness of the opaque 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 45 μm or less, 40 μm or less, or 35 μm or less for handleability. It is preferable from the viewpoint of improving.

(Base resin layer)
As the base resin layer, a thermoplastic resin having excellent impact resistance, abrasion resistance, etc., for example, a thermoplastic resin such as a polyolefin resin, a vinyl polymer, polyester, or a polyamide is used alone or in combination of two or more kinds. It can be used in multiple layers. By using these resins, the base material resin layer can be a transparent base material resin layer. The base resin layer may be a stretched film or a non-stretched film. Further, the base resin layer may be present on one side or both sides of the barrier layer. The barrier layer can be protected by this base resin layer.

Examples of the polyolefin-based resin include polyethylene-based resins and polypropylene-based resins.

In the present specification, the polyethylene-based resin is a resin containing a repeating unit of an ethylene group in the main chain of a polymer in an amount of more than 50 mol%, 60 mol% or more, 70 mol% or more, or 80 mol% or more, for example, low density. Polyethylene (LDPE), Linear low density polyethylene (LLDPE), Medium density polyethylene (MDPE), High density polyethylene (HDPE), Ethylene-acrylic acid copolymer (EAA), Ethylene-methacrylic acid copolymer (EMAA) , Ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate copolymer (EMA), ethylene-vinyl acetate copolymer (EVA), carboxylic acid-modified polyethylene, carboxylic acid-modified ethylene vinyl acetate copolymer, ionomer , And derivatives thereof, and mixtures thereof.

In the present specification, the polypropylene-based resin is a resin containing a repeating unit of a propylene group in the main chain of a polymer in an amount of more than 50 mol%, 60 mol% or more, 70 mol% or more, or 80 mol% or more, for example, polypropylene (PP). Examples include homopolymers, random polypropylene (random PP), block polypropylene (block PP), chlorinated polypropylene, acid-modified polypropylene, derivatives thereof, and mixtures thereof.

Examples of the vinyl polymer include polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), polychlorotrifluoroethylene, polytetrafluoroethylene, polyacrylonitrile (PAN) and the like.

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

Examples of the polyamide include nylon 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 satisfactorily protecting the transparent barrier layer, and 55 μm or less, 50 μm or less, or 45 μm or less. It is preferable from the viewpoint of improving the handleability as a packaging bag.

<Transparent moisture absorbing layer>
The transparent hygroscopic layer is a layer that is transparent and has a hygroscopic agent. In this case, the hygroscopic agent may be dispersed in the thermoplastic resin. As the thermoplastic resin, the thermoplastic resins mentioned for the base resin layer can be used, and among them, it is preferable to use a polyolefin resin, particularly a polyethylene resin, from the viewpoint of processability and the like.

The melt flow rate of the resin composition constituting the transparent moisture absorbing layer when measured in accordance with JIS K7210 under the conditions of a temperature of 190 ° C. and a load of 21.18 N is 0.3 g / 10 min or more and 30 g / 10 min or less. It is preferable from the viewpoint that molding into a film by the T-die method or the inflation method is relatively easy. The melt flow rate may be 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, 20 g / 10 min or less, or 15 g / 10 min or less. It may be 10 g / 10 min or less, 8.0 g / 10 min or less, or 5.0 g / 10 min or less. For example, this melt flow rate may be 0.5 g / 10 min or more and 10 g / 10 min or less.

The haze of the resin composition constituting the transparent moisture-absorbing layer when measured in accordance with JIS K7136 with a film having a thickness of 100 μm before moisture absorption is preferably 80% or less, preferably 70% or less, 60% or less. , 50% or less, 40% or less, 30% or less, 20% or less, or 15% or less, and may be 1% or more, 3% or more, or 5% or more. Here, in the present specification, the "film before moisture absorption" means a film immediately after melting the resin composition and forming a film thereof.

As the hygroscopic agent, a physical hygroscopic agent such as hydrophilic zeolite or silica gel, or a chemical hygroscopic agent such as calcium oxide, magnesium sulfate, calcium chloride, calcium oxide or aluminum oxide can be used. Above all, it is preferable to use hydrophilic zeolite.

As the hydrophilic zeolite, for example, A-type, X-type, or LSX-type zeolite can be used. These may be used alone or in combination.

When a hydrophilic zeolite is used as the hygroscopic agent, the average particle size D50 of the zeolite is preferably 300 nm or less from the viewpoint of imparting appropriate transparency to the composition. Here, the average particle size D50 of zeolite is a cumulative value of 50% in the particle size distribution based on the number of particles obtained by measuring the long axis of 100 randomly selected particles using a scanning electron microscope (SEM). Means the particle size at. The average particle size D50 of the zeolite may be 250 nm or less, 200 nm or less, 150 nm or less, or 100 nm or less. The average particle size D50 of the zeolite may be 10 nm or more, 30 nm or more, 50 nm or more, or 100 nm or more. For example, the average particle size D50 of zeolite may be 10 nm or more and 300 nm or less, or more than 100 nm and 250 nm or less.

When a hydrophilic zeolite is used as the hygroscopic agent, the pore (absorption port) diameter of the zeolite may be 0.3 nm or more and 1 nm or less, and may be 0.3 nm or more and 0.5 nm or less.

When a hydrophilic zeolite is used as a hygroscopic agent, the value of the atomic ratio (Si / Al) of Si and Al in the zeolite is arbitrary, for example, 1 or more, 2 or more, 3 or more, 5 or more, 10 or more, or It may be 15 or more, for example, 80 or less, 60 or less, 50 or less, 40 or less, or 30 or less.

The zeolite used in the present invention is preferably hydrophilic from the viewpoint of hygroscopicity, and it is particularly preferable to use Na-A type zeolite.

The zeolite used in the present invention can be produced, for example, by a method as described in Patent Documents 3 and 4. Such zeolite may be used with its bulk density adjusted as described in Patent Document 2.

The content of the hygroscopic agent is 1% by mass or more, 3% by mass or more, 5% by mass or more, 7% by mass or more, or 10% by mass based on the mass of the entire moisture absorbing layer from the viewpoint of ensuring good moisture absorbing capacity. It is preferably 50% by mass or less, 45% by mass or less, 40% by mass or less, 35% by mass or less, or 30% by mass or less from the viewpoint of ensuring good transparency and film forming property. Is preferable.

It is preferable that the transparent moisture absorbing layer further contains an ester compound having an HLB value of 5 or less from the viewpoint of improving transparency. Here, the HLB value is an index indicating whether it is hydrophilic or lipophilic. When the HLB value of the ester compound is 5 or less, it means that the ester compound has high lipophilicity, and is a numerical value of a region used as an antifoaming agent or an emulsifier of an emulsion, for example. The HLB value may be, for example, 4.5 or less, 4.0 or less, or 3.5 or less, and may be, for example, 2.0 or more, 2.5 or more, or 3.0 or more.

The ester compound is, for example, a monoester compound of a polyhydric alcohol and a fatty acid. The polyhydric alcohol may be, for example, glycerin, alkylene glycol or the like. The fatty acid may be, for example, a saturated or unsaturated fatty acid having 12 or more and 24 or less carbon atoms.

The ester compound may be, in particular, a monoester of an alkylene glycol having 2 or more and 6 or less carbon atoms and a fatty acid having 15 or more and 24 or less carbon atoms. The alkylene glycol may be, for example, ethylene glycol, propylene glycol, diethylene glycol or the like. The above and fatty acids having 15 or more and 24 or less carbon atoms may be saturated or unsaturated, and may be, for example, stearic acid, behenic acid, or the like.

Specifically, the ester compound may be, for example, propylene glycol monostearate, propylene glycol monobehenate, or the like.

The content of the ester compound in the transparent moisture absorbing layer is not particularly limited as long as it can give the advantageous effects of the present invention. For example, the content of the ester compound may be 2.0% by mass or more and 15% by mass or less, and may be 2.5% by mass or more, 3.0% by mass or more, or 5.0% by mass or more. It may be mass% or less, 10 mass% or less, 8.0 mass% or less, or 6.0 mass% or less. For example, the content of the ester compound may be 2.5% by mass or more and 12% by mass or less, or 3.0% by mass or more and 10% by mass or less.

The transparent moisture absorbing layer may or may contain an oxide (excluding zeolite) of one or more elements selected from Al, Si, Ti, and Zr having an average particle diameter D50 of 100 nm or less. It does not have to be. The content of such an oxide may be, for example, 5% by mass or less, 3% by mass or less, 1% by mass or less, or 0% by mass.

The transparent moisture-absorbing layer is obtained by kneading the resin composition constituting the transparent moisture-absorbing layer using, for example, a batch kneader such as a kneader, a Banbury mixer, or a mixing roll conical mixer, or a continuous kneader such as a twin-screw kneader. Then, the kneaded resin can be produced by molding it into a film by an extrusion molding method such as an inflation method or a T-die method. When the transparent skin layer is present on one side or both sides of the transparent moisture absorbing layer, the transparent skin layer and / or the transparent non-adsorption layer and / or the transparent skin layer and / or the transparent non-adsorption layer and / or It may be laminated with a transparent easily peelable layer.

<Discoloring gas absorption layer>
The discoloring gas absorbing layer is a layer containing a thermoplastic resin and a discoloring gas absorbing agent. The discoloring gas absorber may be dispersed in the thermoplastic resin.

(Thermoplastic resin)
As the thermoplastic resin, the thermoplastic resins mentioned for the base resin layer can be used, and among them, it is preferable to use a polyolefin resin, particularly a polyethylene resin, from the viewpoint of processability and the like.

(Discoloring gas absorber)
A discoloring gas absorbent is an absorbent that can discolor by absorbing gas. As the discoloring gas absorber, for example, a metal oxide having an oxygen deficiency such as cerium oxide having an oxygen deficiency and titanium oxide having an oxygen deficiency can be used. These oxygen-deficient metal oxides can be discolored by absorption of oxygen.

A metal oxide having an oxygen deficiency will be described more specifically. In the oxygen deficiency of the metal oxide (MO ₂ ), oxygen is forcibly extracted from the crystal lattice of the metal oxide as represented by the following formula (1) by the reduction treatment in a strongly reducing atmosphere. It is brought about by the oxygen deficiency state (MO _2-x , 0 <x <2). The reduction treatment can be performed, for example, by heat treatment at a high temperature of 1000 ° C. or the like in a reducing atmosphere such as hydrogen gas.
MO ₂ + xH ₂ → MO _2-x + xH ₂ O ・ ・ ・ (1)

Then, as shown in the following formula (2), the oxygen-deficient portion reacts with oxygen to exert its effect as an inorganic oxygen absorber.
MO _2-x + (x / 2) O ₂ → MO ₂ ... (2)

The value of x above can be a positive number of 1.0 or less, and more preferably 0.7 or less. As shown in the above formula (2), the metal oxide does not require the presence of water in the atmosphere in the reaction with oxygen. Therefore, using a metal oxide having an oxygen deficiency as an inorganic oxygen absorber is particularly effective for contents that dislike water.

Further, as the discoloring gas absorber, a simple substance metal such as copper or silver can also be used.

The content of the discoloring gas absorber in the discoloring gas absorbing layer is 1% by mass or more, 3% by mass or more, and 5% by mass or more based on the mass of the entire absorbing layer from the viewpoint of ensuring good absorption capacity. , 7% by mass or more, or 10% by mass or more, and from the viewpoint of ensuring good film-forming property, 70% by mass or less, 65% by mass or less, 60% by mass or less, 55% by mass or less, or It is preferably 50% by mass or less.

<Transparent skin layer>
The transparent skin layer is a layer that contains a resin for a transparent skin layer and can be present on the surface of the transparent moisture absorbing layer opposite to the transparent barrier base material layer. The transparent skin layer may be further present on the surface of the transparent moisture absorbing layer on the transparent barrier base layer side. Further, the transparent skin layer may be fused to the transparent moisture absorbing layer.

In particular, the transparent skin layer can prevent the hygroscopic agent contained in the transparent hygroscopic layer from falling off and coming into contact with the contents. Further, in this case, the transparent skin layer may be a layer that does not contain a hygroscopic agent.

The thickness of the transparent skin layer can be 1 μm or more, 3 μm or more, 5 μm or more, or 7 μm or more, and can be 50 μm or less, 40 μm or less, 30 μm or less, 20 μm or less, or 15 μm or less. When a plurality of transparent skin layers are present, the thickness of each transparent skin layer may be the same or different.

(Resin for transparent skin layer)
As the resin for the transparent skin layer, the thermoplastic resins mentioned for the base resin layer can be used alone or in combination, and among them, the polyolefin-based resin, particularly the polyethylene-based resin, is used from the viewpoint of processability and the like. Is preferable. When skin layers are present on both sides of the transparent moisture absorbing layer, the transparent skin layer resins constituting the transparent skin layers may be the same or different.

<Other layers>
The transparent hygroscopic laminate may have other optional layers. Examples of the other layer include an adhesive layer existing between the layers.

《Packaging bag》
The packaging bag of the present invention includes one or more of the above-mentioned moisture-absorbing and gas-absorbing laminated films, and is on the side opposite to the barrier base material layer side of the one or more moisture-absorbing and gas-absorbing laminated films. A part is bag-shaped by being heat-sealed with another part of this moisture-absorbing and gas-absorbing laminated film or another film. Here, the other film may be another moisture-absorbing and gas-absorbing laminated film, or may be another film other than the moisture-absorbing and gas-absorbing laminated film.

The packaging bag of the present invention can be a packaging bag containing the above-mentioned packaging bag and the contents contained in the packaging bag.

<Contents>
The contents are the contents stored in the packaging bag. The contents are not limited as long as they can be deteriorated by contact with the outside air, and include foods, cosmetics, medical instruments, medical devices, electronic members, precision machines, recording materials, etc. in addition to drugs. Can be done. Further, the drug includes a cleaning agent, a pesticide and the like in addition to a pharmaceutical preparation.

The present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

<< Preparation of a film having an opaque barrier substrate layer >>
<Example 1>
(Making a transparent moisture absorbing film)
A transparent skin layer, a transparent moisture absorbing layer, and a transparent skin layer were arranged in this order by a multi-layer film forming machine, and a two-kind three-layer transparent moisture absorbing film was produced by a coextrusion T-die method. Linear low density polyethylene (LLDPE) is used as the transparent skin layer, and ethylene-vinyl acetate copolymer (EV150, Mitsui DuPont Polychemical Co., Ltd.) 48 parts by mass, Na-A type is used as the transparent moisture absorbing layer. A resin prepared by melting and kneading 32 parts by mass of zeolite (average particle size D50: 50 nm) and 5 parts by mass of an ester compound (propylene glycol monobehenate, HLB value 3.4) at a temperature of 160 ° C. for 10 minutes with a Banbury mixer. The composition was used. The thickness of each layer was 10 μm for the transparent skin layer, 40 μm for the transparent moisture absorbing layer, and 10 μm for the transparent skin layer.

(Preparation of discolorable gas absorbing film)
In a multi-layer film forming machine, the transparent skin layer, the discoloring gas absorption layer (oxygen absorption layer), and the transparent skin layer are arranged in this order, and the discoloration property of 2 types and 3 layers is performed by the coextrusion inflation method. A gas absorbing film was prepared. Linear low-density polyethylene (LLDPE) is used as the transparent skin layer, and cerium oxide CeO _2-x (x = 0.5) 55 parts by mass having oxygen deficiency and low density as the discoloring gas absorbing layer. A resin composition prepared by melting and kneading 45 parts by mass of polyethylene (LDPE) with a Banbury mixer at a temperature of 160 ° C. for 10 minutes was used. The thickness of each layer was 20 μm for the transparent skin layer, 35 μm for the discoloring gas absorbing layer, and 20 μm for the transparent skin layer.

(Laminate)
The prepared discolorable gas absorbing film was laminated on the AL foil side of the laminated body of PET // AL foil as the barrier base material layer using a dry laminate adhesive, and then the discolorable gas absorbing film was laminated. The prepared transparent moisture-absorbing film was laminated with a dry-laminated adhesive to prepare the laminated film of Example 1.

<Comparative example 1>
Instead of the transparent moisture-absorbing layer of the example, 40 parts by mass of the above ethylene-vinyl acetate copolymer, 40 parts by mass of hydrophilic zeolite (Molecular Sieve 3A, Union Showa Co., Ltd.) and 5 parts by mass of the above ester compound are melt-kneaded. A laminated film of Comparative Example 1 was prepared in the same manner as in Example 1 except that an opaque moisture absorbing layer was used.

"evaluation"
<Visibility>
Visibility was evaluated according to the following evaluation criteria:
〇: The discoloration of the discoloring gas absorbing layer can be observed from the side where the AL foil does not exist. ×: The discoloration of the discoloring gas absorbing layer cannot be observed from the side where the AL foil does not exist.

<Hygroscopicity>
The produced laminated film was cut into 100 mm squares and weighed with an electronic balance. The laminated film was exposed for 6 hours in an environment with a temperature of 60 ° C. and a relative humidity of 100% RH. Then, the seasoning was performed for 24 hours in an environment of a temperature of 23 ° C. and a relative humidity of 50% RH, weighed with an electronic balance, the mass change was calculated, and this was converted into the mass change per ^{1 m 2.}

The evaluation criteria are as follows.
〇: The amount of moisture absorbed was 1 g / m ² or more.
X: The amount of moisture absorbed was less than ^{1 g / m 2.}

<Oxygen absorption>
The prepared laminated film was cut into 100 mm squares, sealed in an aluminum bag having a volume of 15 ml with air for the volume, and left to stand for 7 days.

After leaving it to stand, the measuring needle of an oxygen measuring machine (Pack Master RO-103, Iijima Electronics Co., Ltd.) was pierced into this aluminum bag to measure the oxygen concentration, and the oxygen absorption amount per ^{1 cm 2 was calculated from this oxygen concentration.} ..

The evaluation criteria are as follows:
◯: The amount of oxygen absorbed was 0.02 ml / cm ² or more.
X: The amount of oxygen absorbed was less than ^{0.02 ml / cm 2.}

Table 1 shows the configurations and evaluation results of Examples and Comparative Examples.

From Table 1, it is confirmed that the laminated film of Example 1 having the barrier base material layer, the transparent moisture absorbing layer, and the discoloring gas absorbing layer has the moisture absorbing property and the gas absorbing property, and the discoloration of the gas absorbing agent is confirmed. You can understand that you can.

<< Preparation of a film having a transparent barrier base material layer >>
<Example 2>
The above transparent moisture-absorbing film is laminated on a transparent silica vapor-deposited PET film (GX film, relief printing company, thickness 12 μm) as a transparent barrier substrate using a dry laminate adhesive, and then this transparent moisture-absorbing film is laminated. The above-mentioned discolorable gas absorbing film was laminated with a dry laminate adhesive to prepare a laminated film of Example 2.

<Comparative example 2>
Instead of the transparent hygroscopic layer of Example 2, 40 parts by mass of the above ethylene-vinyl acetate copolymer, 40 parts by mass of hydrophilic zeolite (Molecular Sieve 3A, Union Showa Co., Ltd.) and 5 parts by mass of the above ester compound are melted. Using the resin composition prepared by kneading, the laminated film of Comparative Example 2 was prepared in the same manner as in Example 2 except that an opaque moisture absorbing layer was used.

"evaluation"
<Visibility>
Visibility was evaluated according to the following evaluation criteria:
〇: Discoloration of the discoloring gas absorbing layer can be observed from both sides ×: Discoloration of the discoloring gas absorbing layer cannot be observed from the barrier substrate layer side

<Hygroscopic and oxygen absorptive>
Hygroscopicity and oxygen absorption were evaluated in the same manner as above.

Table 2 shows the configurations and evaluation results of Examples and Comparative Examples.

From Table 2, it is confirmed that the laminated film of Example 2 having the barrier base material layer, the transparent moisture absorbing layer, and the discoloring gas absorbing layer has the moisture absorbing property and the gas absorbing property, and the discoloration of the gas absorbing agent is confirmed. You can understand that you can.

In the following, examples of the transparent moisture absorbing layer that can be used in the present invention are shown with reference to reference examples.

<< Reference example: Example of transparent moisture absorbing film >>
<Manufacturing example>
Thermoplastic resin, Na-A type zeolite (average particle size D50: 50 nm), and ester compound (propylene glycol monobehenate, HLB value 3.4) were mixed in the formulations shown in Tables 3 and 4 using a Banbury mixer. Then, the mixture was melt-kneaded at 160 ° C. for 10 minutes to obtain the resin composition of each example.

<evaluation>
(Melt flow rate)
The resin composition of each example was cut to a measurable size. The melt flow rate (MFR) of the cut resin composition was measured using a melt indexer (Techno Seven Co., Ltd.) under the conditions of a temperature of 190 ° C. and a load of 21.18 N in accordance with JIS K7210. ..

(Haze)
The resin composition was cut to a predetermined weight, and a film having a thickness of 100 μm was prepared by hot press molding. Here, the pressing conditions were a temperature of 160 ° C., a pressure of 40 to 60 MPa, and 2 minutes. The film thus obtained was cut into 50 mm squares, and the haze was measured using a haze measuring device (Murakami Color Research Institute Co., Ltd., HR-100) in accordance with JIS K7105. The haze after moisture absorption was measured by allowing the film to stand in an environment of 23 ° C. and 50%, absorbing moisture until the weight change after moisture absorption became constant, and then measuring by the same method as above.

<result>
The configuration and evaluation results of each example are shown in Tables 3 and 4.

With reference to Table 3, it was found that the melt flow rate of the resin composition decreased significantly as the zeolite content increased. This tendency can also be confirmed in Reference Examples 3 and 4. In Reference Comparative Example 1, the melt flow rate was lowered to the extent that it could not be molded by the T-die method or the inflation method.

With reference to Table 4, it was found that as the content of the ester compound decreased, the melt flow rate of the resin composition decreased significantly and the haze increased. In Reference Comparative Example 2, the melt flow rate was lowered to the extent that molding by the T-die method or the inflation method was impossible, and the transparency was also lowered.

10 Moisture-absorbing and gas-absorbing laminated film 12 Barrier base material layer 122 Barrier layer 124 Base material layer 14 Transparent moisture-absorbing layer 16 Transparent skin layer 18 Discoloring gas-absorbing layer

Claims (9)

It has a barrier base material layer, a transparent moisture absorbing layer, and a discoloring gas absorbing layer in this order, or has a barrier base material layer, a discoloring gas absorbing layer, and a transparent moisture absorbing layer in this order.
The transparent hygroscopic layer contains a thermoplastic resin and a hygroscopic agent.
The discolorable gas absorbing layer can be discolored by absorbing the gas.
Moisture-absorbing and gas-absorbing laminated film. The laminated film according to claim 1, wherein the thermoplastic resin of the transparent moisture absorbing layer is a polyolefin resin. The laminated film according to claim 1 or 2, wherein the hygroscopic agent is zeolite. The laminated film according to claim 3, wherein the average particle size D50 of the zeolite in the transparent moisture absorbing layer is 300 nm or less. The laminated film according to any one of claims 1 to 4, wherein the transparent moisture absorbing layer further contains an ester compound having an HLB value of 5 or less. The laminated film according to any one of claims 1 to 5, further comprising a transparent skin layer laminated on one side or both sides of the transparent moisture absorbing layer. The laminated film according to any one of claims 1 to 6, wherein the discoloring gas absorbing layer contains cerium oxide having oxygen deficiency. A part of the laminated film according to any one of claims 1 to 7 on the side opposite to the barrier base material layer side of the one or a plurality of laminated films. Is bag-shaped by being heat-sealed with other parts of this laminated film or with other films.
Packaging bag. The packaging bag according to claim 8, and a packaging bag containing the contents contained in the packaging bag.

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