Gas barrier film and gas barrier laminate

Abstract

To provide a gas barrier film having a structure suitable for recycling, provided with a gas barrier layer containing silicon oxide, while ensuring both transparency and gas barrier functionality.SOLUTION: A gas barrier film 1 comprises a substrate layer 10 and a gas barrier layer 20 which is formed on a first surface 10a of the substrate layer and is composed of a silicon oxide film. The silicon oxide film, as measured by the Karl Fischer method, has a water content per unit film thickness of 1.0 ppm or more and 2.8 ppm or less.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a gas barrier film and a gas barrier laminate. The gas barrier film and gas barrier laminate of the present invention are suitable for packaging food, pharmaceuticals, precision electronic components, etc.

Background Art

[0002] In packaging materials used for packaging contents such as food, non-food, and pharmaceuticals, from the viewpoint of suppressing the deterioration of the contents and maintaining the functions and properties of the contents, oxygen, water vapor, and other gases that deteriorate the contents and permeate through the packaging material are blocked. Gas barrier properties are required. As a packaging material having gas barrier properties, a gas barrier film using a metal foil made of aluminum or the like, which is less affected by temperature, humidity, etc., as a gas barrier layer, is known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, from the viewpoint of suppressing the environmental load, the demand for gas barrier films using a base material layer film made of polyethylene (PE) or polypropylene (PP) has been increasing. Patent Document 1 also provides a laminate excellent in recyclability. However, in the configuration described in Patent Document 1, since there is a layer between the base material layer and the vapor deposition layer, there is an environmental load when manufacturing the gas barrier film, and there is room for further improvement in recyclability from the viewpoint of being a single material.

[0005] Patent Document 2 discloses, as another configuration of the vapor deposition film, a film in which a vapor deposition film of an inorganic oxide such as silicon oxide or aluminum oxide is formed on a base material layer film made of a polymer material by vacuum vapor deposition, sputtering, or the like. These vapor deposition films have transparency and gas barrier properties against gases such as oxygen and water vapor. However, through the inventor's study, it has been found that simply forming a gas barrier layer on a base material layer made of PE or PP is not sufficient to achieve both higher transparency and gas barrier properties.

[0006] In view of the above circumstances, an object of the present invention is to provide a gas barrier film having a structure suitable for recyclability and achieving both transparency and gas barrier properties.

Means for Solving the Problems

[0007] A first aspect of the present invention includes a base material layer and a gas barrier layer formed on a first surface of the base material layer, the gas barrier layer being composed of a silicon oxide film, and the water content per unit film thickness of the silicon oxide film measured by the Karl Fischer method being 1.0 ppm or more and 2.8 ppm or less, a gas barrier film.

[0008] A second aspect of the present invention includes the gas barrier film according to the first aspect and a coating layer formed on the gas barrier layer, the coating layer containing any one of a metal alkoxide, a hydrolyzate of a metal alkoxide, a water-soluble polymer, a polycarboxylic acid-based polymer, a polyvalent metal compound, and a polyvalent metal salt of a carboxylic acid which is a reaction product of a polycarboxylic acid-based polymer and a polyvalent metal compound, a gas barrier laminate.

[0009] A third aspect of the present invention includes the gas barrier film according to the first aspect and a heat seal layer formed on at least one surface side of the gas barrier film, the main component of which is the same as that of the base material layer, a gas barrier laminate.

[0010] The fourth aspect of the present invention is a gas barrier laminate comprising a gas barrier film according to the first aspect, a heat seal layer formed on one surface side of the gas barrier film and having the same main component as the base material layer, and a surface layer formed on the other surface side of the gas barrier film and having the same main component as the base material layer, with a total light transmittance (JIS-K-7361) of 88% or more and a haze of 30% or less.

Advantages of the Invention

[0011] The gas barrier film and gas barrier laminate according to the present invention have a structure suitable for recyclability and achieve both transparency and gas barrier properties.

Brief Description of the Drawings

[0012]

Figure 1

Embodiments for Carrying Out the Invention

[0013] Hereinafter, an embodiment of the present invention will be described with reference to FIG. 1. FIG. 1 is a schematic cross-sectional view of a gas barrier laminate 100 according to the present embodiment. The gas barrier laminate 100 shown in FIG. 1 includes a gas barrier film 1, a coating layer 30, a heat seal layer 40, and a surface layer 60. The gas barrier film 1 includes a base material layer 10 and a gas barrier layer 20.

[0014] The base material layer 10 is a resin film mainly composed of any one of polypropylene, polyethylene, a composite of polypropylene and polyethylene, a composite of polypropylene, polyethylene, and α-olefin, polyvinyl alcohol, and ethylene-vinyl alcohol copolymer. The base material layer 10 may be either an unstretched film or a stretched film. When a stretched film is used as the base material layer 10, the stretching ratio is not particularly limited.

[0015] The thickness of the base material layer 10 is not particularly limited. The base material layer 10 may be a single-layer film in consideration of the use of packaging materials and the like, or may be a multi-layer film formed by laminating films with different properties. Considering the workability when forming the gas barrier layer 20 and the coating layer 30 described later, the thickness of the base material layer 10 is preferably in the range of 3 to 200 μm, particularly preferably in the range of 6 to 80 μm, from a practical perspective.

[0016] The base material layer 10 may contain additives that are not resin components. The additives can be appropriately selected from various known additives. Examples of additives include anti-blocking agents (AB agents), heat stabilizers, weather stabilizers, ultraviolet absorbers, lubricants, slip agents, nucleating agents, antistatic agents, anti-fogging agents, pigments, and dyes. The AB agent may be either organic or inorganic. Any one of these additives may be used alone, or two or more of them may be used in combination. The content of the additive in the base material layer 10 can be appropriately adjusted within a range that does not hinder the effects of the present invention.

[0017] The gas barrier layer 20 is formed on the first surface 10a of the base material layer 10. The gas barrier layer 20 is composed of a silicon oxide film and is a layer that exhibits barrier properties against predetermined gases such as oxygen and water vapor. It is desirable that the gas barrier film 1 be transparent after the gas barrier layer 20 is formed. When forming the gas barrier layer 20 on the base material layer 10, the partial pressure of the film formation chamber may be adjusted by introducing water, oxygen, or the like. The transparency can be improved by adjusting the partial pressure of the film formation chamber. The first surface 10a of the base material layer 10 may be subjected to plasma treatment before forming the gas barrier layer 20. The method of plasma treatment is not particularly limited. Plasma treatment that can be performed inline from the perspective of productivity is preferred. The plasma treatment is not particularly limited to glow discharge, arc discharge, ion beam, etc., and a magnet may be used to increase the plasma density. Also, the gas used for plasma treatment can be selected from any one or a plurality of oxygen, nitrogen, and argon.

[0018] The water content per unit film thickness of the silicon oxide film that constitutes the gas barrier layer 20 and is measured by the Karl Fischer method is 1.0 ppm or more and 2.8 ppm or less.

[0019] The thickness of the gas barrier layer 20 varies depending on the type, composition, and film formation method of the components used for the gas barrier layer 20, but generally can be appropriately set within the range of 3 to 300 nm. If the thickness of the gas barrier layer 20 is less than 3 nm, a uniform film may not be obtained or the film thickness may be insufficient. On the other hand, if the thickness of the gas barrier layer 20 exceeds 300 nm, cracks may occur due to external factors such as bending and stretching after film formation, resulting in loss of barrier properties. Also, if the thickness of the gas barrier layer 20 exceeds 50 nm, there is a risk of losing the transparency of the gas barrier layer 20. For this reason, it is more preferable to set the thickness of the gas barrier layer 20 within the range of 6 to 50 nm.

[0020] The method for forming the gas barrier layer 20 is not particularly limited. As the method for forming the gas barrier layer 20, for example, a vacuum evaporation method, a plasma-activated evaporation method, a sputtering method, an ion plating method, an ion beam evaporation method, a plasma chemical vapor deposition method (CVD), etc. can be adopted. By combining a plasma assist method or an ion beam assist method, etc., the gas barrier layer 20 can be formed densely to improve the gas barrier property and adhesion.

[0021] The gas barrier film 1 of the present embodiment having the above configuration exhibits high gas barrier properties, while the main resin component is polypropylene, and it is also easy to make the ratio of the main resin component in the gas barrier film 1 90% by mass or more. That is, the gas barrier film 1 can be configured as a highly recyclable monomaterial.

[0022] The total light transmittance (JIS-K-7361) of the gas barrier film 1 of the present embodiment is not particularly limited, but may be, for example, 91% or more. Also, the haze of the gas barrier film 1 of the present embodiment is not particularly limited, but may be, for example, 0.9% or less.

[0023] The oxygen transmission rate of the gas barrier film 1 of the present embodiment under 30°C and 70% RH is not particularly limited, but may be, for example, 145 cc / (m 2·day·atm) or less. Also, the water vapor permeability of the gas barrier film 1 of the present embodiment under 40°C and 90% RH is not particularly limited, but for example, it may be 6.2 g / (m 2 ·day) or less.

[0024] The coating layer 30 is formed on the gas barrier layer 20 of the gas barrier film 1 described above. The coating layer 30 protects the gas barrier layer 20 and further enhances the gas barrier property of the gas barrier film 1. The coating layer 30 has an arbitrary configuration and can be omitted, for example.

[0025] As the coating layer 30, a coating layer such as a thermoplastic resin, a thermosetting resin, an ultraviolet curable resin, a metal alkoxide, a water-soluble polymer, a polycarboxylic acid-based polymer, a polyvalent metal compound, or a polyvalent metal salt of a carboxylic acid which is a reaction product of a polycarboxylic acid-based polymer and a polyvalent metal compound can be used. Particularly, a metal alkoxide and a water-soluble polymer having excellent oxygen barrier properties are preferable. This is formed using a coating agent mainly composed of an aqueous solution or a water / alcohol mixed solution containing a water-soluble polymer and one or more metal alkoxides or their hydrolyzates. For example, a coating agent is prepared by mixing a water-soluble polymer dissolved in an aqueous (water or water / alcohol mixed) solvent with a metal alkoxide that has been directly treated or previously hydrolyzed. After applying this coating agent onto the gas barrier layer 20 and drying it, an oxygen barrier film as the coating layer 30 can be formed.

[0026] Each component included in the coating agent for forming the coating layer 30 will be described in more detail. Examples of the water-soluble polymer used in the coating agent include polyvinyl alcohol (PVA), polyvinyl pyrrolidone, starch, methyl cellulose, carboxymethyl cellulose, sodium alginate, and the like. In particular, the use of PVA is preferable because excellent gas barrier properties can be obtained. PVA is generally obtained by saponifying polyvinyl acetate. As PVA, either so-called partially saponified PVA in which several tens of % of acetic acid groups remain or completely saponified PVA in which only several % of acetic acid groups remain can be used. PVA in between the two may also be used.

[0027] The metal alkoxide used in the coating agent is a compound represented by the general formula M(OR)n (M: metal such as Si, Al; R: alkyl group such as CH3, C2H5). Specifically, examples include tetraethoxysilane [Si(OC2H5)4], triisopropoxyaluminum Al[OCH(CH3)2]3, and the like. 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, those having a mercapto group such as 3-mercaptopropyltrimethoxysilane, those having an isocyanate group such as 3-isocyanatopropyltriethoxysilane, and tris-(3-trimethoxysilylpropyl) isocyanurate.

[0028] Examples of the coating method for the coating layer 30 include a casting method, a dipping method, a roll coating method, a gravure coating method, a screen printing method, a reverse coating method, a spray coating method, a kit coating method, a die coating method, a metering bar coating method, a combined chamber doctor coating method, a curtain coating method, and the like.

[0029] The thickness of the coating layer 30 varies depending on the composition of the coating agent used, coating conditions, etc., and is not particularly limited. However, when the film thickness after drying of the coating layer 30 is less than 0.01 μm, a uniform coating film may not be formed and sufficient gas barrier properties may not be obtained. When the film thickness after drying exceeds 50 μm, cracks are likely to occur in the oxygen barrier film as the coating layer 30. Therefore, a suitable thickness of the coating layer 30 is, for example, in the range of 0.01 to 50 μm. The optimal thickness of the coating layer 30 is, for example, in the range of 0.1 to 10 μm.

[0030] The heat seal layer 40 is a heat-fusible layer. The heat seal layer 40 constitutes at least the outermost surface on one side in the thickness direction of the gas barrier laminate 100. In the gas barrier laminate 100 illustrated in FIG. 1, the heat seal layer 40 is formed on the second surface 10b side (one surface side of the gas barrier film 1) of the base material layer 10, and constitutes the outermost surface of the gas barrier laminate 100 facing the second surface 10b side of the base material layer 10. Note that the heat seal layer 40 may be formed, for example, on the first surface 10a side (the other surface side of the gas barrier film 1) of the base material layer 10 and constitute the outermost surface of the gas barrier laminate 100 facing the first surface 10a side of the base material layer 10. That is, the heat seal layer 40 may be formed, for example, by being laminated on the coating layer 30. Further, the heat seal layer 40 may be formed, for example, on both the first surface 10a side and the second surface 10b side of the base material layer 10.

[0031] The main component of the heat seal layer 40 is the same as that of the base material layer 10 used for the gas barrier film 1. Thereby, the gas barrier laminate 100 can be recycled. The thickness of the heat seal layer 40 can be determined according to the purpose, but can be, for example, about 50 to 200 μm. The heat seal layer 40 may be provided by laminating resin films by dry lamination using an adhesive (not shown), or may be provided by extrusion lamination using a fluid resin. A barrier adhesive resin may be used as the adhesive. When a barrier adhesive is used, the gas barrier properties of the gas barrier laminate 100 can be further enhanced.

[0032] As the adhesive, known adhesives for dry lamination can be used. The adhesives for dry lamination are not particularly limited, and specifically include two-component curable ester-based adhesives, ether-based adhesives, urethane-based adhesives, and the like.

[0033] In the gas barrier laminate 100 including the heat seal layer 40 described above, by heat-sealing two or one folded gas barrier laminate 100 with the heat seal layer 40 facing each other, packaging materials such as packages can be easily produced. Also in this case, by making the main resin component (main ingredient) of the heat seal layer 40 the same as the main resin component (main ingredient) of the base material layer 10 used for the gas barrier film 1, the packaging material can be made into a single material.

[0034] The surface layer 60 is formed on the first surface 10a side of the base material layer 10 (the other surface side of the gas barrier film 1) in the gas barrier laminate 100, and constitutes the outermost surface of the gas barrier laminate 100 facing the first surface 10a side of the base material layer 10. In the gas barrier laminate 100 illustrated in FIG. 1, the surface layer 60 is formed at a position sandwiching the gas barrier film 1 between the heat seal layer 40. Specifically, the surface layer 60 is formed by overlapping on the coating layer 30. The main component of the surface layer 60 is the same as that of the base material layer 10 used for the gas barrier film 1. Thereby, the gas barrier laminate 100 can be recycled. The thickness of the surface layer 60 is not particularly limited, but may be, for example, about 15 to 200 μm. The surface layer 60 may function as a printing substrate for providing, for example, a printing layer described later. When the heat seal layer 40 described above is formed by overlapping on the coating layer 30, the surface layer 60 may be formed on the second surface 10b side of the base material layer 10 (one surface side of the gas barrier film 1). Further, the gas barrier laminate 100 may not include the surface layer 60, for example.

[0035] A printing layer (not shown) can be provided on the base material layer 10, heat seal layer 40, and surface layer 60 where the adhesive is provided. Generally, the printing layer is provided at a position visible from the outside of the gas barrier laminate 100 for the purpose of displaying information regarding the contents, identifying the contents, or improving the design of the packaging bag. The printing method and printing ink are not particularly limited, and are appropriately selected from known printing methods and printing inks in consideration of printability on the film, design properties such as color tone, adhesion, and safety as a food container. As the printing method, for example, a gravure printing method, an offset printing method, a gravure offset printing method, a flexographic printing method, an inkjet printing method, etc. can be used. Among them, the gravure printing method can be preferably used from the viewpoints of productivity and high definition of the pattern. Note that the printing layer may be provided as appropriate according to the intended use, or may not be provided.

[0036] In order to enhance the adhesion of the printing layer, various pretreatment such as corona treatment, plasma treatment, frame treatment, etc., or a coating layer such as an easy adhesion layer may be provided on the surface of the layer forming the printing layer.

[0037] In the gas barrier laminate 100 of the present embodiment having the above configuration, since the main components constituting the base material layer 10, heat seal layer 40, and surface layer 60 are the same, it is also easy to set the ratio of the main resin component in the gas barrier laminate 100 to 90% by mass or more. That is, the gas barrier laminate 100 can be configured as a highly recyclable monomaterial.

[0038] The total light transmittance (JIS-K-7361) of the gas barrier laminate 100 of the present embodiment is not particularly limited, but may be, for example, 88% or more. Also, the haze of the gas barrier laminate 100 of the present embodiment is not particularly limited, but may be, for example, 30% or less.

[0039] The oxygen transmission rate of the gas barrier laminate 100 of the present embodiment at 30°C and 70% RH is not particularly limited, but may be, for example, 3.2 cc / (m 2·day·atm) or less. Also, the water vapor transmission rate of the gas barrier laminate 100 of the present embodiment at 40°C and 90% RH is not particularly limited, but for example, it may be 1.9 g / (m 2 ·day) or less.

[0040] As described above, in the gas barrier film 1 of the present embodiment, the gas barrier layer 20 is made of a silicon oxide film, and the water content per unit film thickness of the silicon oxide film measured by the Karl Fischer method is 1.0 ppm or more and 2.8 ppm or less. Thereby, it is possible to provide a gas barrier film 1 having a structure suitable for recyclability and achieving both transparency and gas barrier properties.

[0041] Also, in the gas barrier film 1 of the present embodiment, the total light transmittance (JIS-K-7361) is 91% or more, and the haze is 0.9% or less. Thereby, the transparency of the gas barrier film 1 can be sufficiently ensured.

[0042] Also, in the gas barrier film 1 of the present embodiment, the oxygen transmission rate at 30°C and 70% RH is 145 cc / (m 2 ·day·atm) or less, and the water vapor transmission rate at 40°C and 90% RH is 6.2 g / (m 2 ·day) or less. Thereby, the gas barrier property of the gas barrier film 1 can be sufficiently ensured.

[0043] Also, in the gas barrier laminate 100 of the present embodiment, the total light transmittance (JIS-K-7361) is 88% or more, and the haze is 30% or less. Thereby, the transparency of the gas barrier laminate 100 can be sufficiently ensured.

[0044] Also, in the gas barrier laminate 100 of the present embodiment, the oxygen transmission rate at 30°C and 70% RH is 3.2 cc / (m 2 ·day·atm) or less, and the water vapor transmission rate at 40°C and 90% RH is 1.9 g / (m 2 ·day) or less. Thereby, the gas barrier property of the gas barrier laminate 100 can be sufficiently ensured.

[0045] The gas barrier film of this embodiment will be further described using examples and comparative examples. The present invention is not limited in any way by the specific contents of the examples and comparative examples.

[0046] (Example 1) As the base material layer 10, a biaxially stretched polypropylene film (ME-1 manufactured by Mitsui Chemicals Toagosei Co., Ltd.) was used, and the partial pressure of m / z18 measured by a manometer during film formation in the film formation chamber was adjusted to 0.004 Pa. A gas barrier layer 20 (film thickness: 28.8 nm) made of silicon oxide was formed by electron beam evaporation. Thus, the gas barrier film according to Example 1 was produced.

[0047] A coating agent obtained by mixing the following liquid (1) and liquid (2) at a weight ratio of 6:4 was applied onto the gas barrier layer of the gas barrier film by a gravure coating method and dried to form a coating layer 30 with a thickness of 0.4 μm. (1) Liquid: 89.6 g of hydrochloric acid (0.1 N) was added to 10.4 g of tetraethoxysilane and stirred for 30 minutes for hydrolysis to obtain a hydrolysis solution with a solid content of 3 wt% (in terms of SiO2). (2) Liquid: A 3 wt% aqueous / isopropyl alcohol solution of polyvinyl alcohol (weight ratio of water:isopropyl alcohol 90:10) Furthermore, a biaxially stretched polypropylene film (ME-1 manufactured by Mitsui Chemicals Toagosei Co., Ltd.) was laminated onto the coating layer 30 using a two-component curable polyurethane-based adhesive to provide a surface layer 60. Also, an unstretched polypropylene film (thickness: 70 μm) was provided as a heat seal layer 40 on the second surface 10b side of the base material layer 10 by dry lamination using a two-component curable polyurethane-based adhesive. Thus, the gas barrier laminate according to Example 1 was produced.

[0048] (Example 2) A gas barrier film and a gas barrier laminate of Example 2 were produced in the same manner as in Example 1, except that the partial pressure of m / z18 measured by a manometer during film formation in the film formation chamber was adjusted to 0.011 Pa.

[0049] (Comparative Example 1) A gas barrier film and a gas barrier laminate of Comparative Example 1 were produced in the same manner as in Example 1, except that the partial pressure of m / z 18 measured with a manometer during film formation in the film formation chamber was adjusted to 0.002 Pa.

[0050] (Comparative Example 2) A gas barrier film and a gas barrier laminate of Comparative Example 1 were produced in the same manner as in Example 1, except that the partial pressure of m / z 18 measured with a manometer during film formation in the film formation chamber was adjusted to 0.04 Pa.

[0051] The following evaluations were performed on the gas barrier films and gas barrier laminates of Examples 1 and 2 and Comparative Examples 1 and 2.

[0052] (Evaluation of water content rate of gas barrier layer) The water content rate (unit: %) of the gas barrier film produced by the above procedure was measured. A Karl Fischer moisture meter (AQ-2100ST, EV-2000, manufactured by Hiranuma Sangyo Co., Ltd.) was used for the measurement. The measurement temperature was evaluated at 200 °C. The value obtained by subtracting the water content rate of the base material layer from the measured water content rate of the gas barrier film was defined as the water content rate of the gas barrier layer.

[0053] (Evaluation of optical properties of gas barrier film and gas barrier laminate) The total light transmittance (unit: %) and haze (unit: %) of the gas barrier film and gas barrier laminate produced by the above procedure were evaluated. These optical property evaluations were measured using NDH2000 manufactured by Nippon Denshoku Industries Co., Ltd. in accordance with JIS K 7361-1.

[0054] (Evaluation of gas barrier properties of gas barrier film and gas barrier laminate) The water vapor transmission rate (WVTR) (unit: g / m 2 ·day, measurement conditions: 40 °C - 90% RH) of the gas barrier film and gas barrier laminate produced by the above procedure was evaluated. Mocon's PERMATRAN-W3 / 34 was used for the measurement. Also, the oxygen transmission rate (OTR) (unit: cc / m2 ·day·atm, measurement conditions: 30°C - 70% RH) were evaluated. For the measurement, OX-TRAN Model 2 / 21L manufactured by Mocon was used. The above results are shown in Table 1.

[0055]

Table 1

[0056] In Examples 1 and 2, the moisture content of the gas barrier layer was 1.0 ppm or more and 2.8 ppm or less in both cases. Also, in the gas barrier films of Examples 1 and 2, the total light transmittance was 91% or more, the haze was 0.9% or less, and the oxygen transmission rate was 145 cc / (m 2 ·day·atm) or less, and the water vapor transmission rate at 40°C and 90% RH was 6.2 g / (m 2 ·day) or less. From this, it was confirmed that the gas barrier films of Examples 1 and 2 achieved both transparency and gas barrier properties.

[0057] In Comparative Example 1, the moisture content of the gas barrier layer was less than 1.0 ppm. Also, in the gas barrier film of Comparative Example 1, the oxygen transmission rate was 145 cc / (m 2 ·day·atm) or less, and the water vapor transmission rate at 40°C and 90% RH was 6.2 g / (m 2 ·day) or less. Therefore, the gas barrier film of Comparative Example 1 had good gas barrier properties. However, in the gas barrier film of Comparative Example 1, the total light transmittance was lower than 91% and the haze was greater than 0.9%. For this reason, the gas barrier film of Comparative Example 1 had low transparency and was insufficient.

[0058] In Comparative Example 2, the moisture content of the gas barrier layer was greater than 2.8 ppm. Also, in the gas barrier film of Comparative Example 2, the total light transmittance was 91% or more and the haze was 0.9% or less. Therefore, the gas barrier film of Comparative Example 2 had good transparency. However, in the gas barrier film of Comparative Example 2, the oxygen transmission rate was 145 cc / (m 2·day·atm), and the water vapor transmission rate at 40 °C and 90% RH was greater than 6.2 g / (m 2 ·day). Therefore, the gas barrier film of Comparative Example 2 had low gas barrier properties and was insufficient.

[0059] As described above, one embodiment and examples of the present invention have been explained. However, the specific configuration is not limited to this embodiment, and modifications and combinations of configurations within the scope not departing from the gist of the present invention are also included.

Explanation of Reference Numerals

[0060] 1 Gas barrier film 10 Base material layer 10a First surface 10b Second surface 20 Gas barrier layer 30 Coating layer 40 Heat seal layer 60 Surface layer 100 Gas barrier laminate

Claims

1. A base material layer, and a gas barrier layer formed on a first surface of the base material layer, wherein the gas barrier layer is made of a silicon oxide film, and a water content per unit film thickness of the silicon oxide film measured by the Karl Fischer method is 1.0 ppm or more and 2.8 ppm or less, a gas barrier film.

2. The total light transmittance (JIS-K-7361) is 91% or more, and the haze is 0.9% or less, the gas barrier film according to Claim 1.

3. The oxygen permeability at 30 °C and 70% RH is 145 cc / (m ２ ·day·atm) or less, The water vapor permeability at 40 °C and 90% RH is 6.2 g / (m ２ ·day) or less, The gas barrier film according to Claim 1 or Claim 2.

4. The base material layer is mainly composed of any one of polypropylene, polyethylene, a composite of polypropylene and polyethylene, a composite of polypropylene, polyethylene and α-olefin, polyvinyl alcohol and ethylene-vinyl alcohol copolymer, the gas barrier film according to Claim 1 or Claim 2.

5. The gas barrier film according to Claim 1 or Claim 2, and a coating layer formed on the gas barrier layer, wherein the coating layer contains any one of a metal alkoxide, a hydrolyzate of a metal alkoxide, a water-soluble polymer, a polycarboxylic acid-based polymer, a polyvalent metal compound, and a polyvalent metal salt of a carboxylic acid which is a reaction product of a polycarboxylic acid-based polymer and a polyvalent metal compound, a gas barrier laminate.

6. The gas barrier film according to Claim 1 or Claim 2, and a heat seal layer having the same main component as the base material layer and formed on at least one surface side of the gas barrier film, a gas barrier laminate.

7. The gas barrier film according to Claim 1 or Claim 2, a heat seal layer having the same main component as the base material layer and formed on one surface side of the gas barrier film, and a surface layer having the same main component as the base material layer and formed on the other surface side of the gas barrier film, wherein the total light transmittance (JIS-K-7361) is 88% or more, and the haze is 30% or less, a gas barrier laminate.

8. The oxygen transmission rate at 30°C and 70% RH is 3.2 cc / (m ２ ·day·atm) or less, The water vapor permeability at 40 °C and 90% RH is 1.9 g / (m ２ ·day) or less, The gas barrier laminate according to Claim 5.

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