JP2019107836A - Barrier film - Google Patents

Abstract

To provide a barrier film capable of maintaining oxygen barrier performance even when force is added by deformation such as elongation.SOLUTION: There is provided a barrier film 1 having a substrate 2, an aluminum oxide layer 3, and a fiber layer 4 containing a cellulose fiber in this order, in which a ratio of oxygen permeation of a barrier film 1 after 4% elongation of the barrier film 1 under atmosphere of temperature of 25°C and humidity of 0%RH to oxygen permeation of the barrier film 1 under atmosphere of temperature of 25°C and humidity of 0%RH of 1.5 or less. There is provided a barrier film 1 having oxygen permeation of the barrier film 1 after 4% elongation under atmosphere of temperature of 25°C and humidity of 0%RH of 0.1 cc/(mday atm).SELECTED DRAWING: Figure 1

Description

  Embodiments of the present disclosure relate to barrier films using cellulose fibers.

  The barrier film is mainly used as a packaging material for food and medicine, etc., in order to prevent the influence of oxygen, water vapor, etc. which causes the quality of the contents to be changed, a liquid crystal display, an EL display, a solar cell etc. Is used as a package material for an electronic device or the like in order to avoid the performance deterioration due to contact with the oxygen or water vapor. In addition, for the purpose of imparting flexibility and impact resistance, studies have been made to use a barrier film in a portion where conventional glass or the like is used.

  The barrier film usually has a barrier layer on at least one surface of the substrate. Moreover, the barrier film by which the inorganic layer and the organic layer were alternately laminated | stacked by the at least one surface of a base material as a structure which expresses high barrier performance is known. The inorganic layer is the layer that contributes most to the barrier performance, and silicon oxide, for example, is widely used as the material of the inorganic layer.

  By the way, in recent years, cellulose nanofibers have attracted attention as a new plant-derived material. Then, applying a cellulose nanofiber in a barrier film is examined (for example, patent document 1).

JP, 2010-125814, A

  Patent Document 1 discloses a gas barrier laminate having a base, a first layer made of an inorganic compound, and a second layer containing a cellulose fiber. In the barrier film, the inorganic layer is generally a vapor-deposited film, and it is difficult to follow deformation such as elongation or bending, and often has brittleness. Therefore, in a barrier film having a base material, an inorganic layer, and a cellulose fiber layer in this order, long-term barrier performance is maintained even when it has been confirmed that sufficient barrier performance can be exhibited. You may not be able to In particular, when a force due to deformation such as elongation is applied to the barrier film, the barrier performance may be degraded even if the barrier film has high initial barrier performance.

  The present invention has been made in view of the above problems, and its main object is to provide a barrier film capable of maintaining oxygen barrier performance even when a force due to deformation such as elongation is applied.

  As a result of repeated researches to solve the above problems, the present inventors have found that, in the barrier film having a base material, an inorganic layer, and a fiber layer containing cellulose fibers in this order, when the barrier film is elongated, Since tensile stress is applied, defects such as micro cracks are easily generated in the inorganic layer, but it has been found that by using aluminum oxide in the inorganic layer, the oxygen barrier performance is maintained, and the present invention has been completed.

  That is, the present disclosure is a barrier film having a base material, an aluminum oxide layer, and a fiber layer containing a cellulose fiber in this order, and the barrier film has a temperature of 25 ° C. and an humidity of 0% RH. The barrier film has an oxygen permeability ratio of 1.5 or less under an atmosphere of 25 ° C. temperature and 0% RH humidity of the barrier film after 4% elongation of the barrier film to oxygen permeability. provide.

  The present disclosure has the effect of being able to provide a barrier film capable of maintaining the oxygen barrier performance even when a force such as elongation is applied.

It is a schematic sectional drawing which shows an example of the barrier film of this indication.

  Hereinafter, the barrier film of the present disclosure will be described in detail.

  In the present specification, the "barrier film" also includes members called "barrier sheets" and the like.

  The barrier film of the present disclosure has a base material, an aluminum oxide layer, and a fiber layer containing a cellulose fiber in this order, and the oxygen permeability of the barrier film in an atmosphere of 25 ° C. and 0% RH. The ratio of the oxygen permeability of the barrier film in an atmosphere of 25 ° C. and 0% RH is 1.5 or less, after the barrier film is elongated by 4%.

  In the present specification, “oxygen permeability in an atmosphere with a temperature of 25 ° C. and a humidity of 0% RH” of the barrier film is referred to as “initial oxygen permeability”, and “the barrier film is elongated by 4%” The oxygen permeability of the barrier film at a temperature of 25 ° C. and an humidity of 0% RH may be referred to as “oxygen permeability after 4% elongation”. In addition, “The barrier film has a temperature of 25 ° C. and a humidity of 0% RH, and the barrier film has a temperature of 25 ° C. and a humidity of 0% RH after stretching the barrier film by 4% with respect to the oxygen permeability The ratio of oxygen permeability may be referred to as "deterioration of oxygen permeability after 4% elongation".

The barrier film of the present disclosure will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view showing an example of the barrier film of the present disclosure. As shown in FIG. 1, the barrier film 1 has a base material 2, an aluminum oxide layer 3 and a fiber layer 4 containing cellulose fibers in this order. And, the deterioration degree of the oxygen permeability after 4% elongation of the barrier film 1 is 1.5 or less.

  The barrier film of the present disclosure has a high oxygen barrier since defects such as cracks and pinholes generated in the aluminum oxide layer can be covered with the cellulose fibers contained in the fiber layer by having the aluminum oxide layer and the fiber layer in this order. Performance can be expressed.

Here, even in the case of a barrier film having a high initial barrier performance, the oxygen barrier performance may be lowered when a force due to deformation such as elongation is applied. In a barrier film having a base material, an inorganic layer, and a fiber layer containing cellulose fibers in this order, the reduction in oxygen barrier performance is the generation of defects such as micro cracks in the inorganic layer when the barrier film is elongated. It is considered to be attributable. The inorganic layer used for the barrier film is generally a vapor-deposited film, and it is often difficult to follow deformation such as elongation or bending and the like to be fragile. When the barrier film is stretched, a tensile stress is applied to the inorganic layer, so micro cracks are easily generated in the inorganic layer.
Therefore, for example, when processing the barrier film, such as printing, laminating, bag-making, filling and packaging, sealing, molding, etc., when the force due to deformation such as elongation is applied to the barrier film, the inorganic layer may And the oxygen barrier performance of the barrier film as a whole may be degraded. In particular, when the barrier film is applied to a molded product, it is considered that a large force is applied to the barrier film and the elongation becomes large.
In addition, the oxygen barrier performance of the barrier film as a whole is obtained even when the barrier film is subjected to a force due to deformation or the like when transporting the product including the barrier film at the time of transportation of the packaging material or transportation of packaging articles. It may decrease.
Furthermore, the base material used for the barrier film is generally a resin base material, and when the barrier film is exposed to a high temperature for a long time, the base material thermally expands and contracts. When the base material is stretched, tensile stress is applied to the inorganic layer, so defects such as micro cracks are easily generated in the inorganic layer. Therefore, even when a barrier film or a product including the barrier film is used in a high temperature environment, the oxygen barrier performance may be deteriorated with time.
When a defect such as a micro crack occurs in the inorganic layer constituting the barrier film, the defect spreads with time, and the oxygen barrier performance may be deteriorated with time. In this case, the oxygen barrier performance falls short of the design value.

  On the other hand, in the present disclosure, the barrier film has a base material, an aluminum oxide layer, and a fiber layer containing cellulose fibers in this order, and the oxygen permeability of the barrier film after 4% elongation. When the degree of deterioration is within the predetermined range, high oxygen barrier performance can be maintained even when a force such as elongation is applied.

  Although the reason for this is not clear, it is presumed as follows. That is, in the barrier film of the present disclosure, an aluminum oxide layer is used as the inorganic layer, and the adhesion between the aluminum oxide layer and the fiber layer is good. Therefore, when a force such as elongation is applied, aluminum oxide is used. The fiber layer can easily follow the layer. For this reason, even if defects such as micro cracks are generated in the aluminum oxide layer due to stress due to deformation such as elongation, the increase in oxygen permeability is suppressed by filling the defects with cellulose fibers contained in the fiber layer, It is believed that good oxygen barrier performance can be maintained.

  On the other hand, in a barrier film having a base material, an inorganic layer, and a fiber layer containing cellulose fibers in this order, when the adhesion between the inorganic layer and the fiber layer is poor, a force such as elongation is applied. Peeling occurs at the interface between the inorganic layer and the fiber layer, which may lower the oxygen barrier performance.

  Thus, the gas barrier film of the present disclosure can maintain high oxygen barrier performance even when a force such as elongation is applied. Therefore, the gas barrier film of the present disclosure can maintain good oxygen barrier performance for a long time. That is, the gas barrier film of the present disclosure can maintain the oxygen barrier performance as designed.

  Hereinafter, each structure of the barrier film of this indication is demonstrated.

1. Properties of Barrier Film (1) Oxygen Permeability of Barrier Film In the present disclosure, the barrier after 4% elongation of the barrier film with respect to the oxygen permeability in an atmosphere of 25 ° C. temperature and 0% RH humidity. The ratio of oxygen permeability in an atmosphere of film temperature 25 ° C. and humidity 0% RH is 1.5 or less. In the present disclosure, when the degradation degree of the oxygen permeability after 4% elongation of the barrier film is in the above range, the oxygen permeability can be maintained low even when a force due to deformation such as elongation is applied. . Therefore, the oxygen barrier performance can be maintained for a long time.

The oxygen permeability of the barrier film of the present disclosure in an atmosphere with a temperature of 25 ° C. and a humidity of 0% RH can be 0.1 cc / (m ² · day · atm) or less, and more preferably 0.05 cc / (m ²⁾ -It is preferable that it is below day atm). When the initial oxygen permeability of the barrier film is in the above range, a barrier film having high oxygen barrier performance can be obtained.

In addition, after 4% elongation of the barrier film of the present disclosure, the oxygen permeability of the barrier film in an atmosphere with a temperature of 25 ° C. and a humidity of 0% is set to 0.1 cc / (m ² · day · atm) or less. It is preferable that it is less than 0.06 cc / (m ² · day · atm). When the oxygen permeability after 4% elongation of the barrier film is in the above range, a barrier film having high oxygen barrier performance can be obtained.

  The oxygen permeability of the barrier film at the initial stage and after 4% elongation is JIS K 7126-2: 2006 (plastic-film and sheet-gas permeability test method-part 2: equivalent pressure method, Appendix A: electrolysis Measuring the condition of carrier gas and test gas under the condition of temperature 25 ° C and humidity 0% RH using oxygen gas permeability measuring device with reference to test method of oxygen gas permeability by sensor method) Can. As an oxygen gas permeability measuring device, for example, "OXTRAN Model 2/21 10X" manufactured by MOCON Co., USA can be used.

For the measurement of initial oxygen permeability, a test piece prepared by cutting the barrier film to a desired size is prepared, the test piece is mounted in the apparatus, and the carrier area is approximately 50 cm ² (permeation area: circle with a diameter of 8 cm). Adjust the gas and test gas conditions to a temperature of 25 ° C and a humidity of 0% RH. At the time of the measurement, the carrier gas is supplied into the device at a flow rate of 10 cc / min for 60 minutes or more for purging. The carrier gas may be nitrogen gas containing about 5% hydrogen. After purge, a test gas is flowed into the above-mentioned apparatus, and measurement is performed after securing 12 hours as the time from the start of flow to the time to reach equilibrium. The test gas uses at least 99.5% dry oxygen.

  Also, the oxygen permeability after 4% elongation is measured in the following procedure. That is, first, a barrier film is cut into a rectangle having a width of 100 mm and a length of 150 mm to collect a test piece. Next, the specimen is stretched 4%. Thereafter, the oxygen permeability of the obtained test piece is measured in the same method and conditions as the above-mentioned measurement method and conditions.

(2) Haze Value of Barrier Film The haze value of the barrier film of the present disclosure is preferably 3.0% or less. When the initial haze value of the barrier film is in the above range, a highly transparent barrier film can be obtained.

  Furthermore, the barrier film of the present disclosure preferably has a haze value of 3.0% or less after 4% elongation of the barrier film. When the haze value after 4% elongation of the barrier film is in the above range, a highly transparent barrier film can be obtained.

In addition, the haze value after the initial stage and 4% elongation of a barrier film can be respectively measured using a haze meter based on JISK7136 (how to obtain | require the haze of a plastics-transparent material). As the haze meter, for example, "HM-150" manufactured by Murakami Color Research Laboratory can be used.
The haze value after 4% elongation is measured in the following procedure. That is, first, a barrier film is cut into a rectangle having a width of 100 mm and a length of 150 mm to collect a test piece. Next, the specimen is stretched 4%. Then, the haze value of the obtained test piece is measured by the above-mentioned measurement method.

2. Fiber Layer The fiber layer in the present disclosure is a member containing cellulose fibers.

  Cellulose fibers used in the present disclosure include, for example, those derived from wood, rice, cotton, hemp, kenaf and the like, and those derived from organisms such as bacterial cellulose, valonia cellulose and squirt cellulose. In addition, regenerated cellulose, cellulose derivatives and the like can also be used.

  In order to sufficiently improve the oxygen barrier performance, the cellulose fiber is preferably as fine as possible, and specifically, cellulose nanofibers are preferable.

  The average fiber diameter of the cellulose fiber is preferably on the order of nanometers, and can be, for example, 1000 nm or less, preferably 500 nm or less, more preferably 100 nm or less, and 50 nm or less More preferable. When the average fiber diameter is in the above range, the oxygen barrier performance can be improved and the transparency can be enhanced. On the other hand, the lower limit of the average fiber diameter is about 1 nm in consideration of the productivity of cellulose fibers.

  In addition, the average fiber length of the cellulose fiber can be on the nanometer order or on the micrometer order, and can be, for example, 100 nm or more, and can be 100 μm or less.

  The cellulose fiber preferably has an aspect ratio (average fiber length / average fiber diameter), which is the ratio of average fiber diameter to average fiber length, of 10 or more, and more preferably 50 or more, and more preferably 100 or more. When the aspect ratio is in the above range, the oxygen barrier performance can be improved and the transparency can be enhanced.

  Cellulose fibers can be obtained by cleaving and microfibrillating cellulose fibers. As a means to micro-fibrillate, various grinding devices, such as a ball mill, a millstone grinder, a high pressure homogenizer, a mixer etc., can be mentioned, for example. As the cellulose fiber, a commercial product of an aqueous dispersion of microfibrillated cellulose fiber may be used.

  Moreover, in the manufacturing process of the fiber product which uses a cellulose fiber as a cellulose fiber, the aggregate | assembly of the cellulose fiber taken out as a waste thread can also be used. The process of producing a textile product may include spinning, weaving, non-woven fabric production, and processing of textiles. The aggregate of these cellulose fibers is one in which the cellulose fibers are scraped after passing through these steps, so the cellulose fibers become finer.

  Alternatively, bacterial cellulose produced by bacteria can be used as the cellulose fiber. Examples of bacterial cellulose include those produced as acetic acid bacteria of the genus Acetobacter as producing bacteria. Plant cellulose is formed by convergence of cellulose molecular chains, and very thin microfibrils are formed in bundles. On the other hand, cellulose produced from acetic acid bacteria is originally in the form of a ribbon having a width of about 20 nm to about 50 nm, and forms a very thin network as compared to plant cellulose. Bacterial cellulose may coexist with acetic acid as the bacteria produce acetic acid with the cellulose. In that case, it is preferable to replace the solvent with water.

Moreover, after oxidizing cellulose fiber in presence of a N-oxyl compound as a cellulose fiber, you may use oxidized cellulose fiber obtained by passing through water washing and disintegration.
As the N-oxyl compound, for example, 2,2,6,6-tetramethyl-1-piperidine-N-oxyl (hereinafter referred to as TEMPO), 4-acetamido-TEMPO, 4-carboxy-TEMPO, 4- Phosphonooxy-TEMPO etc. can be used. The addition of these N-oxyl compounds is sufficient at a catalytic amount, and can usually be in the range of 0.1% by mass or more and 10% by mass or less based on the cellulose fiber (absolutely dry basis).
First, such an N-oxyl compound is added to the reaction aqueous solution in a catalytic amount range. Sodium hypochlorite or sodium chlorite is added to the aqueous solution as a co-oxidant, and the reaction is allowed to proceed by adding an alkali metal bromide. In the oxidation reaction of cellulose fiber, the pH is maintained at around 10 by adding an alkaline compound such as an aqueous solution of sodium hydroxide, and the reaction is continued until no change in pH is observed. The reaction temperature can be room temperature. After the reaction, it is preferable to remove the N-oxyl compound remaining in the system. For washing, various methods such as filtration and centrifugation can be adopted. After that, using various pulverizing apparatuses as described above, it is possible to obtain finely divided oxidized cellulose fibers through physical disintegration.

The fiber layer may contain other components as long as the properties thereof are not significantly impaired. Examples of other components include water-soluble polymers, saccharides, coupling agents, inorganic compounds and the like. Furthermore, as another component, additives, such as a dispersing agent, a stabilizer, a viscosity modifier, and a coloring agent, are mentioned, for example.
In addition, a fiber layer does not need to contain components other than the component which may be mixed in the manufacturing process of a cellulose fiber. In this case, the process of forming the fiber layer can be simplified.

  The thickness of the fiber layer can be, for example, 100 nm or more, preferably 300 nm or more, and more preferably 500 nm or more. The thickness can be 10 μm or less, preferably 5 μm or less, and more preferably 1 μm or less. When the thickness of the fiber layer is in the above range, high oxygen barrier performance and transparency can be realized.

  As a formation method of a fiber layer, the method of apply | coating the composition containing a cellulose fiber on an inorganic layer is mentioned, for example.

The composition comprising cellulose fibers can contain a solvent. As a composition containing cellulose fiber, for example, an aqueous dispersion of cellulose fiber can be used.
The aqueous dispersion of cellulose fiber is obtained by dispersing cellulose fiber in water. The content of cellulose fibers in the aqueous dispersion can be, for example, in the range of 0.01% by mass or more and 50% by mass or less.
The aqueous dispersion of cellulose fiber can be obtained, for example, by stirring purified water and cellulose fiber with a mixer or the like.
Moreover, when using bacterial cellulose as a cellulose fiber, you may use what carried out solvent substitution by immersing bacterial cellulose in purified water as a water dispersion of cellulose fiber.

  It does not specifically limit as a coating method of the composition containing a cellulose fiber, A well-known coating method can be employ | adopted suitably.

  Moreover, after applying the composition containing a cellulose fiber, you may dry as needed. The drying method is not particularly limited, and a known drying method can be appropriately adopted.

3. Aluminum oxide layer The aluminum oxide layer in the present disclosure is a member composed of aluminum oxide.

  The aluminum oxide layer preferably has transparency. As mentioned above, it is because it can be set as the barrier film which has transparency.

  The aluminum oxide layer is preferably a vapor deposited film. It is because the vapor deposition film of aluminum oxide has high adhesiveness with a base material, and can exhibit high barrier performance.

  The thickness of the aluminum oxide layer is not particularly limited as long as the desired barrier performance can be exhibited, and can be, for example, 5 nm or more, preferably 10 nm or more, and particularly preferably 15 nm. It is preferable that it is more than. Further, the thickness can be 100 nm or less, preferably 50 nm or less, and particularly preferably 30 nm or less. If the thickness of the aluminum oxide layer is too thin, the film formation may be insufficient and the desired barrier performance may not be exhibited. Moreover, when the said thickness is too thick, it is because there exists a possibility that a crack may occur easily.

  The aluminum oxide layer may be subjected to surface treatment such as corona discharge treatment from the viewpoint that barrier performance and adhesion with the fiber layer can be improved.

  As a formation method of an aluminum oxide layer, the dry film forming method is mentioned, for example, A physical vapor deposition (PVD) method can be used specifically ,. Note that chemical vapor deposition (CVD) may be used.

4. Substrate The substrate in the present disclosure is a member supporting the above-described aluminum oxide layer and fiber layer.

  The substrate is preferably a transparent substrate. As mentioned above, it is because it can be set as the barrier film which has transparency.

  As a base material, a resin base material can be used, for example. The resin substrate may be unstretched or uniaxially or biaxially stretched.

  The resin used for the substrate is not particularly limited, and, for example, a polyolefin resin such as polyethylene and polypropylene, a polyester resin such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate (PBT), Cyclic polyolefin resin, polystyrene resin, acrylonitrile-styrene copolymer (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), poly (meth) acrylic resin, polycarbonate resin, ethylene-vinyl ester copolymer and the same It is possible to use various resins such as saponified products, various polyamide resins such as nylon, polyimide resins, polyurethane resins, acetal resins, and cellulose resins.

  The substrate may contain various plastic additives, additives and the like. Examples of the additive include a lubricant, a crosslinking agent, an antioxidant, an ultraviolet light absorber, a light stabilizer, a filler, a reinforcing agent, an antistatic agent, a pigment, a resin for modification, and the like.

  The substrate may be subjected to surface treatment. It is because adhesion with an aluminum oxide layer can be improved. Examples of the surface treatment include oxidation treatment, roughening treatment (roughening treatment), easy adhesion coating treatment, and the like disclosed in JP-A-2014-180837.

  In addition, the base material may be a single layer, or may be a laminate in which a plurality of resin layers are laminated. Each resin layer in the laminate may be made of different resins, or may be made of the same resin.

  The thickness of the substrate is not particularly limited, but can be, for example, 10 μm or more. The thickness can be set to 1000 μm or less, preferably 500 μm or less, and more preferably 100 μm or less.

5. Barrier Film The barrier film of the present disclosure may have a substrate, an aluminum oxide layer and a fiber layer in this order, for example, may have an aluminum oxide layer and a fiber layer in order on one side of the substrate. An aluminum oxide layer and a fiber layer may be sequentially provided on both sides of the substrate.

  Moreover, the barrier film of this indication may have another member in the range which does not impair the effect of this invention other than a base material, an aluminum oxide layer, and a fiber layer as needed. As another member, the protective layer which protects an aluminum oxide layer and a fiber layer, the heat-welding layer which can be heat-sealed etc. can be mentioned, for example.

  The present disclosure is not limited to the above embodiment. The above-described embodiment is an exemplification, which has substantially the same configuration as the technical idea described in the claims of the present disclosure, and exhibits the same operation and effect as the present invention. It is included in the technical scope of the disclosure.

  Examples and comparative examples are shown below, and the present disclosure is described in more detail.

Example 1
10 g of bleached softwood kraft pulp was disintegrated with water and immersed in a total of 500 mL of water. To this, 0.1 g of 2,2,6,6-tetramethyl-1-piperidine-N-oxyl (TEMPO) previously dissolved in 70 mL of water and 1 g of sodium bromide were added. Here, 70 mL of sodium hypochlorite was added dropwise to initiate the reaction. The pH of the system was maintained at 10 with a 0.5 N aqueous solution of sodium hydroxide. When the pH fluctuation subsided, it was washed repeatedly with water repeatedly. Distilled water was added to the washed pulp to a solid content concentration of 1%, and a transparent cellulose dispersion was prepared using a high-speed rotation homogenizer and an ultrasonic homogenizer.

Next, a polyethylene terephthalate (hereinafter referred to as PET) film with a thickness of 12 μm is used as a base material, and AlO ₂ (aluminum oxide) is used as a deposition source on the upper surface to form an aluminum oxide layer with a thickness of 20 nm by PVD. , Alumina deposited film was obtained. Subsequently, the above-mentioned cellulose dispersion was applied by an applicator on the upper surface of the aluminum oxide layer to form a fiber layer having a dry film thickness of about 600 nm, thereby producing a barrier film.

Comparative Example 1
The alumina vapor deposition film used in Example 1 was used as the barrier film of Comparative Example 1.

Comparative Example 2
First, in the same manner as in Example 1, a cellulose dispersion was prepared.
Next, a polyethylene terephthalate (hereinafter referred to as PET) film with a thickness of 12 μm was used as a substrate, and SiO ₂ (silicon oxide) was used as a deposition source on the top surface to form a silicon oxide layer with a thickness of 20 nm by PVD. . Subsequently, the above-mentioned cellulose dispersion was applied by an applicator on the upper surface of the silicon oxide layer to form a fiber layer having a dry film thickness of about 600 nm, thereby producing a barrier film.

[Evaluation]
(Oxygen permeability)
The initial oxygen permeability of the barrier film of Example 1 and Comparative Examples 1 and 2 is in accordance with JIS K 7126-2: 2006, and an oxygen gas permeability measuring apparatus (OXTRAN Model 2/21 10X, manufactured by MOCON, USA) The conditions of the carrier gas and the test gas were adjusted and measured at a temperature of 25 ° C. and a humidity of 0% RH. The measurement conditions were as described in “1. Characteristics of barrier film (1) Oxygen permeability of barrier film”.

  Further, the barrier films of Example 1 and Comparative Examples 1 and 2 are cut into rectangles with a width of 100 mm and a length of 150 mm to collect test pieces, and after the test pieces are elongated by 4%, the above-mentioned measurement method and measurement conditions The oxygen permeability after 4% elongation was measured.

(Adhesiveness)
The adhesion of the barrier films of Example 1 and Comparative Example 2 was evaluated by the cross cut method (JIS K 5600-5-6). The judgment criteria were as follows.
○: no peeling (JIS K 5600-5-6 Class 0)
:: With peeling (JIS K 5600-5-6 Class 1, 2 or 3)
X: Exfoliated (JIS K 5600-5-6 Class 4 or 5)

(Haze value)
The haze value of the barrier film of Example 1 and Comparative Examples 1 and 2 was measured according to JIS K 7136 using a haze meter (manufactured by Murakami Color Research Laboratory, trade name: HM-150).

1 ... barrier film 2 ... base material 3 ... aluminum oxide layer 4 ... fiber layer

Claims (3)

A barrier film comprising a substrate, an aluminum oxide layer, and a fiber layer containing cellulose fibers in this order,
The barrier film has a temperature of 25 ° C. and a humidity of 0% RH after the barrier film is stretched by 4% with respect to the oxygen permeability in the atmosphere of a temperature of 25 ° C. and a humidity of 0% RH. Barrier film, wherein the ratio of oxygen permeability is 1.5 or less. The oxygen permeability of the barrier film under an atmosphere of a temperature of 25 ° C. and a humidity of 0% is 0.1 cc / (m ² · day · atm) or less after 4% elongation of the barrier film. Item 2. The barrier film according to item 1.   The barrier film according to claim 1 or 2, wherein the haze value of the barrier film after 4% elongation of the barrier film is 3.0% or less.

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