JP2021109381A - Gas barrier film, laminate using the same, and method for producing gas barrier film - Google Patents

Abstract

To provide a gas barrier film which has high resistance to hot water treatment and also suppresses an environmental load, a laminate using the same, and a method for producing the gas barrier film.SOLUTION: In the gas barrier film according to one embodiment of the present invention, a gas barrier layer and a coating layer are laminated in this order on at least one surface of a substrate comprising a polymer material. The substrate comprises a block copolymer obtained by block copolymerization of propylene and ethylene. The block copolymer has a melting point measured by differential scanning calorimetry of 160°C or higher. The gas barrier film has an oxygen permeability at 30°C and 70% RH of 3 cc/m2 day atm or less and a water vapor permeability at 40°C and 90% RH of 1 g/m2 day or less.SELECTED DRAWING: Figure 1

Description

The present invention relates to a gas barrier film, a laminate using the gas barrier film, and a method for producing a gas barrier film.

In packaging materials used for packaging foods, non-foods, pharmaceuticals, etc., from the viewpoint of suppressing deterioration of the contents and maintaining their functions and properties, oxygen, water vapor, and other gases that change the contents that permeate the packaging materials. Gas barrier properties that block the gas may be required. As a packaging material having a gas barrier property, a gas barrier film using a metal foil such as aluminum, which is less affected by temperature, humidity, etc., as a gas barrier layer is known.

As another configuration of the gas barrier film, a film in which a vapor-deposited film of an inorganic oxide such as silicon oxide or aluminum oxide is formed on a base film made of a polymer material by vacuum vapor deposition, sputtering, or the like is known ( For example, see Patent Document 1.). These gas barrier films have transparency and gas blocking properties such as oxygen and water vapor. As the base film, one made of polyethylene terephthalate (PET) is often used.

In recent years, recycling of plastics used for packaging materials and packaging has become important. In order to enable recycling, the packaging material must be composed of a single material, but currently PET is used as the base material of the barrier film, and polypropylene (PP) or polyethylene (PE) is used as the sealant. In many cases. The barrier film substrate and the sealant substrate must be composed of a single material to allow recycling.

Japanese Unexamined Patent Publication No. 60-49934

In recent years, there has been an increasing demand for gas barrier films using polypropylene (PP) or polyethylene (PE) base films from the viewpoint of suppressing the burden on the environment. Patent Document 1 also describes that a base film made of PP or PE can be used.

However, the inventor's study has revealed that a gas barrier film in which a barrier layer is simply formed on a base film made of PP or PE does not actually have sufficient resistance to hot water treatment such as boiling and retort.

Based on the above circumstances, an object of the present invention is to provide a gas barrier film having high resistance to hot water treatment and suppressing an environmental load, a laminate using the gas barrier film, and a method for producing the same.

The first aspect of the present invention is a gas barrier film in which a gas barrier layer and a coating layer are laminated in this order on at least one surface of a base material made of a polymer material, and the base material is a block copolymer of propylene and ethylene. The block copolymer is composed of a block copolymer having a melting point of 160 ° C. or higher as measured by differential scanning calorimetry, an oxygen permeability of 3 cc / m ² · day · atm or less at 30 ° C. and 70% RH, and a pressure of 40 ° C. and 90% RH. It is characterized in that the water vapor permeability is 1 g / m ^{2 · day or less.}

A second aspect of the present invention is a laminate in which a sealant layer made of a heat-sealable thermoplastic resin is laminated on the coating layer of the gas barrier film.

A third aspect of the present invention is a step of forming a gas barrier layer on at least one surface of a substrate made of a resin having a melting point of 160 ° C. or higher measured by differential scanning calorimetry, which comprises a block copolymer obtained by block copolymerizing propylene and ethylene. This is a method for producing a gas barrier film, which comprises a step of forming a coating layer on the gas barrier layer.

According to the present invention, it is possible to provide a gas barrier film having high resistance to hot water treatment and suppressing environmental load.

It is a schematic cross-sectional view of the gas barrier film which concerns on one Embodiment of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.

FIG. 1 is a schematic cross-sectional view of the gas barrier film 1 according to the present embodiment. The gas barrier film 1 includes a base material 10, a pretreatment layer 10a, a gas barrier layer 30, a coating layer 40, an adhesive layer 50, and a sealant layer 60.

The base material 10 contains a film made of a block copolymer obtained by block copolymerizing propylene and ethylene. The base material 10 may be either an unstretched film or a stretched film. When a stretched film is used, the stretch ratio is not particularly limited. The thickness of the base material 10 is not particularly limited. As the base material 10, a single-layer film or a multilayer film in which films having different properties are laminated can be used in consideration of the use of the packaging material and the like. Considering the processability when forming the gas barrier layer 30, the coating layer 40, and the like, the thickness of the base material 10 is practically preferably in the range of 3 to 200 μm, and particularly preferably 6 to 30 μm.

Each layer formed on the base material 10 may be formed on both sides of the base material 10. A layer containing various well-known additives and stabilizers such as antistatic agent, ultraviolet ray inhibitor, antioxidant, plasticizer, lubricant and the like may be provided on one side or both sides of the base material 10.

The ratio of propylene to ethylene constituting the block copolymer is not particularly limited. It is appropriately selected according to the application such as heat resistance, low temperature impact resistance, transparency, and heat sealability.

As the block copolymer constituting the base material 10, one having a melting point of 160 ° C. or higher is used. The melting point and calorific value of melting can be measured with a differential scanning calorimeter (DSC measurement). DSC measurement is a method of measuring the temperature difference between the sample and the reference material as a function of temperature while changing the temperature of the sample part and the reference material by a certain program. The glass transition temperature, melting point, and crystallization of the sample. The temperature, heat of fusion, etc. can be obtained. By using a block copolymer of polypropylene and ethylene having a melting point of 160 ° C. or higher as measured by differential scanning calorimetry as the base material 10, the resistance of the gas barrier film to hot water treatment can be improved.

It is preferable that the base material 10 has little dimensional change after hot water treatment. The dimensional change in the MD and TD directions after the hot water treatment is preferably 2% or less. If it exceeds 2%, the gas barrier layer may be cracked, which may reduce the gas barrier property or the adhesion in the gas barrier film.

The base material 10 preferably contains fine particles as an AB (anti-blocking) agent. When the base material 10 contains fine particles, the number of fine particles protruding from the surface is 80 or less in a square region of 135 μm square, and the average height of the portion protruding from the surface is 5 μm or less. preferable. When the number of AB agents exceeds 80 or the average height exceeds 5 μm, the barrier property may be lowered due to defects in the barrier layer, and sufficient barrier properties may not be obtained.

Further, it is preferable that the average surface roughness (Sa) of the base material 10 is 10 nm or less and the average length (RSm) of the elements is 600 nm or less. If the average surface roughness (Sa) of the surface of the base material exceeds 10 nm, the barrier property may be lowered due to defects in the barrier layer, and sufficient barrier property may not be obtained.

Before forming the gas barrier layer, a coating layer such as a thermoplastic resin, a thermosetting resin, or an ultraviolet curable resin, a corona treatment, a plasma treatment, an ozone treatment, or a flame is used as the pretreatment layer 20 to improve the barrier property and adhesion. Processing or the like may be performed. The method for forming the pretreatment layer is not particularly limited. From the viewpoint of productivity, plasma treatment that can be performed in-line is preferable. The plasma treatment is not particularly limited to glow discharge, ion beam, etc., and a magnet may be used to increase the plasma density. The gas used for the plasma treatment can be selected from one or more of oxygen, nitrogen and argon.

The gas barrier layer 30 is a layer containing any one of metallic aluminum, aluminum oxide, silicon oxide, and silicon oxide containing carbon as a main component, and exhibits a barrier property against a predetermined gas such as oxygen and water vapor. The gas barrier layer 30 may be transparent or opaque.

The thickness of the gas barrier layer 30 varies depending on the type, composition, and film forming method of the inorganic compound used, but is generally set appropriately within the range of 3 to 300 nm. If the thickness of the gas barrier layer 30 is less than 3 nm, a uniform film may not be obtained or the film thickness may not be sufficient, and the function as the gas barrier layer may not be sufficiently exhibited. If the thickness of the gas barrier layer 30 exceeds 300 nm, the gas barrier layer 30 becomes hard, and there is a possibility that the gas barrier layer 30 may be cracked and lose its barrier property due to external factors such as bending and pulling after the film formation. The thickness of the gas barrier layer 30 is preferably in the range of 6 to 150 nm.

The method for forming the gas barrier layer 30 is not limited, and for example, a vacuum deposition method, a sputtering method, an ion plating method, an ion beam method, a plasma vapor deposition method (CVD), or the like can be used. By combining the plasma assist method and the ion beam assist method, the gas barrier layer can be formed densely to improve the barrier property and the adhesion.

The coating layer 40 further enhances the barrier property of the gas barrier layer 30. The coating layer 40 is formed by using an aqueous solution containing a water-soluble polymer and one or more metal alkoxides or a hydrolyzate thereof, or a coating agent containing a water / alcohol mixed solution as a main component. For example, a coating agent is prepared by dissolving a water-soluble polymer in an aqueous (water or water / alcohol mixed) solvent and directly or preliminarily hydrolyzing the metal alkoxide. The coating layer 40 can be formed by applying this coating agent on the gas barrier layer 30 and then drying it.

Each component contained in the coating agent for forming the coating layer 40 will be described in more detail. Examples of the water-soluble polymer used in the coating agent include polyvinyl alcohol (PVA), polyvinylpyrrolidone, starch, methyl cellulose, carboxymethyl cellulose, sodium alginate and the like. In particular, PVA is preferable because excellent gas barrier properties can be obtained. PVA is generally obtained by saponifying polyvinyl acetate. As the PVA, either a so-called partially saponified PVA in which several tens of percent of acetic acid groups remain, or a complete PVA in which only a few percent of acetic acid groups remain can be used. PVA in between the two may be used.

The metal alkoxide used in the coating agent is a compound represented by the general formula, M (OR) n (metal of M: Si, Al, alkyl group of _{R: CH 3,} C ₂ H _{5, etc.).} Specific examples thereof include tetraethoxysilane [Si (OC ₂ H ₅ ) ₄ ] and triisopropoxyaluminum Al [OCH (CH ₃ ) ₂ ] ₃ . Examples of the silane coupling agent include those having an epoxy group such as 3-glycidoxypropyltrimethoxysilane, those having an amino group such as 3-aminopropyltrimethoxysilane, and mercapto groups such as 3-mercaptopropyltrimethoxysilane. Examples thereof include those having an isocyanate group of 3-isocyanatepropyltriethoxysilane, tris- (3-trimethoxysilylpropyl) isocyanurate, and the like. The coating method is not limited, and conventionally known methods such as a dipping method, a roll coating method, a screen printing method, a spray method, and a gravure printing method, which are usually used, can be appropriately selected.

The thickness of the coating layer 40 varies depending on the composition of the coating agent, coating conditions, and the like, and is not particularly limited. However, if the film thickness of the coating layer 40 after drying is 0.01 μm or less, the coating film may not be uniform and sufficient gas barrier properties may not be obtained. If the film thickness after drying exceeds 50 μm, cracks are likely to occur in the coating layer 40. Therefore, the suitable thickness of the coating layer 40 is, for example, in the range of 0.01 to 50 μm. The optimum thickness of the coating layer 40 is, for example, in the range of 0.1 to 10 μm.

The sealant layer 60 is a layer that is joined by heat fusion when forming a bag-shaped package or the like using the gas barrier film 1. Materials for the sealant layer 60 include polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-methacrylate copolymer, ethylene-methacrylate copolymer, ethylene-acrylic acid copolymer, and ethylene-acrylic acid ester. Examples of resin materials such as polymers and their metal crosslinked products can be exemplified. The thickness of the sealant layer 60 is determined according to the purpose, and is, for example, in the range of 15 to 200 μm.

The adhesive layer 50 joins the sealant layer 60 and the coating layer 40. By using the adhesive layer 50, the resin film to be the sealant layer 60 and the base material 10 on which the gas barrier layer 30 and the coating layer 40 are formed can be bonded by dry lamination. As the material of the adhesive layer 50, a two-component curable polyurethane-based adhesive can be exemplified.

A method for producing the gas barrier film 1 of the present embodiment having the above configuration will be described.

First, the gas barrier layer 30 is formed on one surface of the base material 10 (first step). Next, the above-mentioned coating agent is applied onto the gas barrier layer 30 and dried to form a coating layer 40 on the gas barrier layer (second step). Further, an adhesive is applied on the coating layer 40, and a resin film to be the sealant layer 60 is attached (third step). The gas barrier film 1 is completed through the above steps.

The gas barrier film 1 according to the present embodiment has high resistance to hot water treatment by using the above-mentioned block copolymer as the base material 10. Specifically, the oxygen permeability (30 ° C. 70% RH) of the gas barrier film 1 before hot water treatment is 3 cc / m ² · day · atm or less, and the water vapor permeability (40 ° C. 90% RH) is 1 g / m. if ² · day or less, sufficient oxygen barrier property and water vapor barrier properties can be obtained.

The gas barrier film of the present embodiment will be further described with reference to Examples and Comparative Examples. The present invention is not limited to the specific contents of Examples and Comparative Examples.

(Example 1)
As the base material 10, a film (thickness 20 μm) made of a resin obtained by block-copolymerizing propylene and ethylene and adjusted so that the height of the AB agent on the surface of the base material was 2.0 μm or less was used. In the vacuum apparatus, aluminum was evaporated to form a gas barrier layer 30 (thickness 50 nm) made of metallic aluminum by an electron beam vapor deposition method.

On the gas barrier layer 30, a coating agent obtained by mixing the following liquids (1) and (2) at a weight ratio of 6: 4 was applied by a gravure coating method and dried to form a coating layer 40 having a thickness of 0.4 μm. ..
Solution (1) Solution: Hydrolyzed solution (2) _{with a solid content of 3 wt% (SiO 2} equivalent) obtained by adding 89.6 g of hydrochloric acid (0.1N) to 10.4 g of tetraethoxysilane and stirring for 30 minutes to hydrolyze. 3 wt% water / isopropyl alcohol solution of polyvinyl alcohol (water: isopropyl alcohol weight ratio 90:10)

Finally, a stretched polypropylene film (thickness 70 μm) to be the unsealant layer 60 is bonded onto the coating layer 40 by dry laminating using a two-component curable polyurethane adhesive to form the gas barrier laminate of Example 1. Obtained.

(Example 2)
The gas barrier laminate of Example 2 was produced in the same manner as in Example 1 except that the vapor deposition material was Al and oxygen was introduced to form a gas barrier layer 30 having a thickness of 10 nm made of aluminum oxide.

(Example 3)
The gas barrier laminate of Example 2 was produced in the same manner as in Example 1 except that the vapor deposition material was SiO and a gas barrier layer 30 having a thickness of 30 nm made of silicon oxide was formed.

(Example 4)
The gas barrier film of Example 4 was produced in the same manner as in Example 1 except that the vapor deposition material was HMDSO and a gas barrier layer 30 having a thickness of 30 nm made of silicon oxide containing carbon formed by plasma was formed.

(Example 5)
The gas barrier laminate of Example 5 was produced in the same manner as in Example 1 except that the vapor deposition materials were SiO and Al and a gas barrier layer 30 having a thickness of 30 nm made of SiAlOx was formed.

(Example 6)
The gas barrier laminate of Example 6 was produced in the same manner as in Example 1 except that the vapor deposition material was SiO and a gas barrier layer 30 having a thickness of 30 nm made of silicon oxynitride containing nitrogen formed by plasma was formed.

(Example 7)
A gas barrier laminate of Example 7 was prepared in the same manner as in Example 1 except that the base material was subjected to plasma treatment with Ar gas as a pretreatment to continuously form aluminum.

(Example 8)
A gas barrier laminate of Example 8 was prepared in the same manner as in Example 2 except that the base material was subjected to plasma treatment with Ar gas as a pretreatment to continuously form aluminum oxide.

(Example 9)
A gas barrier laminate of Example 9 was prepared in the same manner as in Example 3 except that the base material was subjected to plasma treatment with Ar gas as a pretreatment to continuously form silicon oxide.

(Example 10)
A gas barrier laminate of Example 10 was prepared in the same manner as in Example 4 except that the base material was subjected to plasma treatment with Ar gas as a pretreatment to continuously form silicon oxide containing carbon.

(Example 11)
A gas barrier laminate of Example 11 was prepared in the same manner as in Example 1 except that a urethane resin layer was formed on the base material as a pretreatment.

(Example 12)
A gas barrier laminate of Example 12 was prepared in the same manner as in Example 2 except that a urethane resin layer was formed on the base material as a pretreatment.

(Example 13)
A gas barrier laminate of Example 13 was prepared in the same manner as in Example 3 except that a urethane resin layer was formed on the base material as a pretreatment.

(Example 14)
A gas barrier laminate of Example 14 was prepared in the same manner as in Example 4 except that a urethane resin layer was formed on the base material as a pretreatment.

(Example 15)
A gas barrier laminate of Example 15 was prepared in the same manner as in Example 1 except that the average height of the AB agent on the surface of the base material was set to 4 μm.

(Example 16)
The gas barrier laminate of Example 16 was prepared in the same manner as in Example 2 except that the average height of the AB agent on the surface of the base material was set to 4 μm.

(Example 17)
The gas barrier laminate of Example 17 was prepared in the same manner as in Example 3 except that the average height of the AB agent on the surface of the base material was set to 4 μm.

(Example 18)
The gas barrier laminate of Example 18 was prepared in the same manner as in Example 4 except that the average height of the AB agent on the surface of the base material was set to 4 μm.

(Example 19)
The gas barrier laminate of Example 19 was prepared in the same manner as in Example 5 except that the average height of the AB agent on the surface of the base material was set to 4 μm.

(Example 20)
The gas barrier laminate of Example 20 was prepared in the same manner as in Example 6 except that the average height of the AB agent on the surface of the base material was set to 4 μm.

(Example 21)
The gas barrier laminate of Example 21 was prepared in the same manner as in Example 7 except that the average height of the AB agent on the surface of the base material was set to 4 μm.

(Example 22)
The gas barrier laminate of Example 22 was prepared in the same manner as in Example 8 except that the average height of the AB agent on the surface of the base material was set to 4 μm.

(Example 23)
The gas barrier laminate of Example 23 was prepared in the same manner as in Example 9 except that the average height of the AB agent on the surface of the base material was set to 4 μm.

(Example 24)
The gas barrier laminate of Example 24 was prepared in the same manner as in Example 10 except that the average height of the AB agent on the surface of the base material was set to 4 μm.

(Example 25)
The gas barrier laminate of Example 25 was prepared in the same manner as in Example 11 except that the average height of the AB agent on the surface of the base material was set to 4 μm.

(Example 26)
The gas barrier laminate of Example 26 was prepared in the same manner as in Example 12 except that the average height of the AB agent on the surface of the base material was set to 4 μm.

(Comparative Example 1)
A gas barrier laminate of Comparative Example 1 was prepared in the same manner as in Example 1 except that a film made of a resin obtained by randomly copolymerizing propylene and ethylene was used as the base material.

(Comparative Example 2)
A gas barrier laminate of Comparative Example 2 was prepared in the same manner as in Example 2 except that a film made of a resin obtained by randomly copolymerizing propylene and ethylene was used as the base material.

(Comparative Example 3)
A gas barrier laminate of Comparative Example 3 was prepared in the same manner as in Example 3 except that a film made of a resin obtained by randomly copolymerizing propylene and ethylene was used as the base material.

(Comparative Example 4)
A gas barrier laminate of Comparative Example 4 was prepared in the same manner as in Example 4 except that a film made of a resin obtained by randomly copolymerizing propylene and ethylene was used as the base material.

(Comparative Example 5)
A gas barrier laminate of Comparative Example 5 was prepared in the same manner as in Example 5 except that a film made of a resin having a melting point of 130 ° C. was randomly copolymerized with propylene and ethylene as a base material.

(Comparative Example 6)
A gas barrier laminate of Comparative Example 6 was prepared in the same manner as in Example 6 except that a film made of a resin having a melting point of 130 ° C. was randomly copolymerized with propylene and ethylene as a base material.

(Comparative Example 7)
A gas barrier laminate of Comparative Example 7 was prepared in the same manner as in Example 7 except that a film made of a resin having a melting point of 130 ° C. was randomly copolymerized with propylene and ethylene as a base material.

(Comparative Example 8)
A gas barrier laminate of Comparative Example 8 was prepared in the same manner as in Example 8 except that a film made of a resin having a melting point of 130 ° C. was randomly copolymerized with propylene and ethylene as a base material.

(Comparative Example 9)
A gas barrier laminate of Comparative Example 9 was prepared in the same manner as in Example 9 except that a film made of a resin having a melting point of 130 ° C. was randomly copolymerized with propylene and ethylene as a base material.

(Comparative Example 10)
A gas barrier laminate of Comparative Example 10 was prepared in the same manner as in Example 10 except that a film made of a resin having a melting point of 130 ° C. was randomly copolymerized with propylene and ethylene as a base material.

(Comparative Example 11)
A gas barrier laminate of Comparative Example 11 was prepared in the same manner as in Example 11 except that a film made of a resin having a melting point of 130 ° C. was randomly copolymerized with propylene and ethylene as a base material.

(Comparative Example 12)
A gas barrier laminate of Comparative Example 12 was prepared in the same manner as in Example 12 except that a film made of a resin having a melting point of 130 ° C. was randomly copolymerized with propylene and ethylene as a base material.

(Comparative Example 13)
A gas barrier laminate of Comparative Example 13 was prepared in the same manner as in Example 2 except that the average height of the AB agent on the surface of the base material was set to 6 μm.

(Comparative Example 14)
A gas barrier laminate of Comparative Example 14 was prepared in the same manner as in Example 6 except that the average height of the AB agent on the surface of the base material was set to 6 μm.

(Comparative Example 15)
A gas barrier laminate of Comparative Example 15 was prepared in the same manner as in Example 10 except that the average height of the AB agent on the surface of the base material was set to 6 μm.

(Comparative Example 16)
A gas barrier laminate of Comparative Example 16 was prepared in the same manner as in Example 3 except that the average height of the AB agent on the surface of the base material was set to 6 μm.

(Comparative Example 17)
A gas barrier laminate of Comparative Example 17 was prepared in the same manner as in Example 7 except that the average height of the AB agent on the surface of the base material was set to 6 μm.

(Comparative Example 18)
A gas barrier laminate of Comparative Example 18 was prepared in the same manner as in Example 11 except that the average height of the AB agent on the surface of the base material was set to 6 μm.

(Evaluation of gas barrier layer adhesion after hot water treatment)
Two gas barrier laminates of each example were laminated with the sealant layers 60 facing each other, and the three sides were joined by heat fusion to prepare a pouch (packaging container) of each example. After filling the pouches of each example with water as the contents, one open side was sealed by heat fusion. Then, as hot water treatment, retort sterilization treatment (121 ° C. for 30 minutes) was performed.

After hot water treatment, a test piece was cut out from the part in contact with the contents of the pouch of each example in accordance with JIS Z1707, and the peel strength of the gas barrier layer 30 measured using the Orientec Tencilon universal testing machine RTC-1250. Was measured as an index of adhesion. Two types of measurement, T-shaped peeling and 180 ° peeling, were performed under normal conditions (Dry) and measurement site wetness (Wet), respectively.

(Evaluation of gas barrier performance after hot water treatment)
After preparing the pouches of each example prepared by the above procedure and treating them with hot water, the pouches are opened and the oxygen permeability of the gas barrier film (unit: cc / m ² · day · atm, measurement conditions: 30 ° C.-70% RH). ), and water vapor permeability ^{(unit: g} / m 2 · day, measurement conditions: 40 ℃ -90% RH) were evaluated.

The results are shown in Tables 1 and 2.

In the gas barrier films according to Examples 1 to 26, by using a block copolymer of propylene and ethylene having a melting point of 160 ° C. or higher as a base material, deterioration of oxygen permeability and water vapor permeability due to hot water treatment is suppressed. It was excellent in barrier properties of oxygen and water vapor after hot water treatment. Further, in the gas barrier films according to Examples 1 to 24, the dimensional change before and after the hot water treatment was suppressed, and the adhesion between the base material and the sealant after the hot water treatment was also good.

On the other hand, since the gas barrier films according to Comparative Examples 1 to 12 used a random copolymer of propylene and ethylene having a melting point of 130 ° C. as a base material, oxygen after hot water treatment was compared with Examples 1 to 24. And the barrier property of water vapor was inferior. Further, the gas barrier film according to Comparative Examples 1 to 12 had a dimensional change of more than 2% in the MD direction before and after the hot water treatment, which was larger than that of Examples 1 to 24. Further, in the gas barrier films according to Comparative Examples 13 to 18, the average height of the fine particles (AB agent) precipitated from the surface of the base material exceeds 5 μm, so that the water vapor permeability before the hot water treatment and / Alternatively, the oxygen permeability and the water vapor permeability were higher than those in Examples 1 to 24.

The gas barrier film of the present invention is suitable for packaging foods, pharmaceuticals, precision electronic parts and the like.

1 Gas barrier film 10 Base material 10a Pretreatment layer 30 Gas barrier layer 40 Coating layer 50 Adhesive layer 60 Sealant layer

Claims (12)

A gas barrier layer and a coating layer are laminated in this order on at least one surface of a base material made of a polymer material.
The base material is a block copolymer obtained by block copolymerizing propylene and ethylene, and the block copolymer has a melting point of 160 ° C. or higher as measured by differential scanning calorimetry.
Oxygen permeability under 30 ° C. 70% RH after formation of base material, gas barrier layer and coating layer is 3 cc / m ² · day atm or less, and water vapor permeability at 40 ° C. 90% RH is 1 g / m ² · day or less. A gas barrier film characterized by being. The gas barrier film according to claim 1, wherein the dimensional change in the MD and TD directions before and after hot water treatment at a temperature of 90 ° C. or higher for 30 minutes or longer is 2.0% or less. The claim is characterized in that any one of a thermoplastic resin layer, a thermosetting resin layer and an ultraviolet curable resin layer, or a pretreatment layer by plasma treatment is provided on at least one surface of the base material. The gas barrier film according to any one of 1 and 2. Claim 1 is characterized in that the number of fine particles protruding from the surface of the base material is 80 or less in a 135 μm square, and the average height of the fine particles protruding from the surface of the base material is 5 μm or less. The gas barrier film according to any one of ~ 3. The gas barrier film according to any one of claims 1 to 4, wherein the average surface roughness (Sa) of the base material is 10 nm or less, and the average length (RSm) of the elements is 600 nm or less. The gas barrier film according to any one of claims 1 to 5, wherein the gas barrier layer or the coating layer contains at least one of a metal, an inorganic compound, a metal alkoxide, and a water-soluble polymer. The gas barrier film according to any one of claims 1 to 6, wherein the barrier layer contains any one of metallic aluminum, aluminum oxide, and silicon oxide as a main component or a composite component. The gas barrier film according to any one of claims 1 to 7, wherein the coating layer contains either or both of a metal alkoxide and a water-soluble polymer. A laminate characterized by laminating a sealant layer made of a heat-sealable thermoplastic resin on the coating layer of the gas barrier film according to any one of claims 1 to 8. The laminate according to claim 9, wherein the sealant layer is laminated on the coating layer via an adhesive. 9. The laminate described. A step of forming a gas barrier layer on at least one surface of a base material made of a resin having a melting point of 160 ° C. or higher measured by differential scanning calorimetry, which is a block copolymer composed of block copolymers of propylene and ethylene, and a coating layer on the gas barrier layer. A method for producing a gas barrier film, which comprises a step of forming a gas barrier film.

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