JP6467867B2 - Transparent gas barrier film - Google Patents

Description

  INDUSTRIAL APPLICABILITY The present invention is suitably used in the field of packaging of food, daily necessities, pharmaceuticals, etc., and in fields such as solar cell-related members and electronic device-related members, particularly when both high gas barrier properties and flex resistance are required. The present invention relates to a transparent gas barrier film.

  Packaging materials used for packaging of food, daily necessities, pharmaceuticals, etc., suppress the alteration of the contents, so that the functions and properties can be maintained even during packaging, oxygen, water vapor, etc. that permeate the packaging material, It is necessary to prevent the influence of the gas that alters the contents, and it is required to have a gas barrier property that blocks these gases.

  As packaging materials having ordinary gas barrier properties, vinylidene chloride resin films or films coated with vinylidene chloride resins that are relatively excellent in gas barrier properties have been often used. However, these packaging materials have high gas barrier properties. Cannot be used for packaging that requires Therefore, when a high gas barrier property is required, a packaging material in which a metal foil such as aluminum is laminated as a gas barrier layer has to be used. A packaging material in which a metal foil such as aluminum is laminated has almost no influence of temperature and humidity and has a high gas barrier property. However, these packaging materials have many disadvantages, such as being unable to see the contents through them, having to be disposed of as non-combustible materials after use, and being unable to use metal detectors to inspect the contents. Had.

  As a packaging material that overcomes these drawbacks, Patent Document 1 discloses that a gas barrier layer is formed by depositing a thin film layer of a transparent inorganic oxide such as silicon oxide, aluminum oxide, or magnesium oxide on a base layer made of a transparent plastic film. In addition, a laminated film obtained by laminating an appropriate gas barrier coating layer thereon is disclosed.

  On the other hand, in recent years, the solar cell market is rapidly expanding with increasing interest in global warming issues. As a solar cell structure, a single solar cell element is not used as it is, and generally several to several tens of elements are wired in series and in parallel, and packaged to protect the element for a long period of time. Is done and unitized. The unit built in this package is called a solar cell module. Generally, the surface that is exposed to sunlight is covered with glass, the gap is filled with a filler made of thermoplastic, and the back is made of a heat-resistant, weather-resistant plastic material, etc. The structure is protected by a sheet.

  Since these solar cell modules are used outdoors, sufficient durability and weather resistance are required in the materials used and their configurations. In particular, the back protective sheet is required to have high gas barrier properties as well as weather resistance. This is because the filler in the unit is peeled off due to the permeation of moisture and the wiring is corroded, which adversely affects the module output itself.

  Conventionally, as this back surface protection sheet for solar cells, a laminated structure in which an aluminum foil is sandwiched from both sides with a white fluorine-based film has been often used. However, this fluorine-based film has a weak mechanical strength, so that the solar cell element and the aluminum foil are short-circuited to adversely affect the battery performance. Further, since the price is high, it is necessary to reduce the price of the solar cell module. There are two obstacles. In order to improve these problems, there is an increasing demand for a gas barrier film having both weather resistance and high gas barrier properties without using an aluminum foil.

  Also, development has been made to make this solar cell module flexible, and in order to achieve this, it is necessary to replace the glass substrate on the surface where the sunlight hits with a sheet made of a plastic material, etc. Similarly to the back protective sheet, weather resistance and high gas barrier properties are required.

  In recent years, as electronic paper and organic EL, which are expected as next-generation flat panel displays (FPD), have been developed, there is a demand to replace glass substrates with plastic films in order to achieve flexibility in these FPDs. It is growing. The glass substrate has a gas barrier property required to suppress deterioration of internal elements due to oxygen and water vapor derived from the environment. However, the above-mentioned gas barrier film for packaging materials does not reach the barrier level, and in electronic paper, organic EL, etc. to which a plastic film can be applied, the gas barrier is 100 to 10,000 times that of a food packaging material barrier film. It is said that sex is necessary.

  In order to realize a plastic film having such a high gas barrier property, dry coating methods such as reactive vapor deposition using electron beam vapor deposition and induction heating vapor deposition, sputtering, and plasma CVD (chemical vapor deposition) are used. The formed inorganic oxide thin film has been studied as one that can be expected to exhibit high gas barrier properties.

  Among them, a silicon oxide thin film formed by a plasma CVD method using an organosilane compound has been studied as a barrier layer exhibiting high gas barrier properties, and has been put into practical use in the food packaging field. Patent Document 2 reports that adhesion and transparency are improved by controlling the carbon concentration and the composition of the silicon oxide thin film.

Japanese Patent Laid-Open No. 7-164591 Japanese Patent Laid-Open No. 11-322981

  However, since the laminated film described in Patent Document 1 uses a biaxially stretched polypropylene (OPP) film as a base film, compared to a polyethylene terephthalate (PET) film generally used as a gas barrier base material. Since the gas barrier property is inferior and the surface is inactive, there is a problem in improving the adhesion with the inorganic oxide thin film laminated thereon. Therefore, this configuration is not suitable for applications requiring high gas barrier properties.

  Moreover, the transparent barrier film described in Patent Document 2 is not intended for FPD applications such as electronic paper and organic EL that require high gas barrier properties, and there is a problem with these applications.

  The present invention is excellent in oxygen barrier properties and water vapor barrier properties, such as the backside and surface protective sheets of solar cell modules, protective sheets for FPDs such as electronic paper and organic EL, which were insufficient with conventional gas barrier films, An object is to provide a transparent gas barrier film.

As means for solving the above-mentioned problems, the invention described in claim 1 is represented by a transparent first gas barrier layer made of a metal oxide and a chemical formula SiO _x C _y on a transparent film substrate surface. As a set of composite gas barrier layers composed of a transparent second gas barrier layer in which x of silicon oxide is 1.5 or more and 2.0 or less and y of carbon is 0.2 or more and 0.5 or less, A transparent gas barrier film formed by laminating two or more gas barrier layers, wherein the thickness of the first gas barrier layer is 1 nm or more and 3 nm or less, and the thickness of each of the second gas barrier layers is 1 nm or more and 4 nm or less. In addition, the transparent gas barrier film is characterized in that the total thickness of the laminated composite gas barrier layer is 10 nm or more.

  The invention described in claim 2 is the transparent gas barrier film according to claim 1, wherein the second gas barrier layer is formed by a plasma CVD method.

  According to a third aspect of the present invention, in the transparent gas barrier according to the first or second aspect, the first gas barrier layer is made of any one of silicon oxide, aluminum oxide, titanium oxide, and magnesium oxide. It is a sex film.

  The invention described in claim 4 is the transparent gas barrier film according to any one of claims 1 to 3, wherein the first gas barrier layer is formed by a vacuum deposition method.

The invention according to claim 5 is characterized in that the arithmetic average roughness Ra of the surface of the transparent film substrate on which the first gas barrier layer is formed is 1 nm or less. The transparent gas barrier film according to any one of the above.

  According to the present invention, on the transparent film substrate surface, a transparent first gas barrier layer made of a metal oxide, and x of silicon oxide represented by the chemical formula SiOxCy is 1.5 or more and 2.0 or less, and y of carbon Is a transparent gas barrier film formed by laminating two or more layers of the composite gas barrier layers in this order as a pair of composite gas barrier layers composed of a transparent second gas barrier layer having a thickness of 0.2 to 0.5 The thickness of each of the first gas barrier layer and the second gas barrier layer is 1 nm or more and 5 nm or less, and the total thickness of the laminated composite gas barrier layer is 10 nm or more. A transparent gas barrier film superior in oxygen barrier property and water vapor barrier property can be provided. Due to such excellent gas barrier properties, it can be used as a transparent member for solar cell modules and FPDs.

It is sectional drawing of 1st Embodiment of the transparent gas barrier film which concerns on this invention. It is sectional drawing of 2nd Embodiment of the transparent gas barrier film which concerns on this invention.

  Hereinafter, the present invention will be specifically described with reference to the drawings.

  FIG. 1 shows a cross-sectional view of a transparent gas barrier film obtained by laminating a first gas barrier layer and a second gas barrier layer twice on one surface of a transparent film substrate as a first embodiment. Indicates. Specifically, the first gas barrier layers 2 and 4 made of metal oxide and an oxidation represented by the chemical formula SiOxCy (x is 1.5 or more and 2.0 or less, y is 0.2 or more and 0.5 or less) The second gas barrier layers 3 and 5 made of silicon are sequentially laminated.

As a second embodiment, FIG. 2 shows a cross-sectional view of a transparent gas barrier film obtained by laminating a first gas barrier layer and a second gas barrier layer three times. Specifically, it is represented by the first gas barrier layers 2, 4, 6 made of a metal oxide and the chemical formula SiOxCy (x is 1.5 or more and 2.0 or less, y is 0.2 or more and 0.5 or less). The second gas barrier layers 3, 5, 7 made of silicon oxide are sequentially laminated.

  In the transparent gas barrier film according to the present invention, the transparent film substrate 1 is made of a transparent plastic film. For example, polyester films such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyolefin films such as polyethylene and polypropylene, polyether sulfone (PES), polystyrene film, polyamide film, polyvinyl chloride film, polycarbonate film, polyacrylic Examples thereof include nitrile films, polyimide films, biodegradable plastic films such as polylactic acid, and the like.

  The transparent film substrate 1 may be either stretched or unstretched, but is preferably excellent in mechanical strength and dimensional stability. In particular, polyethylene terephthalate stretched in the biaxial direction is preferably used from the viewpoints of heat resistance and dimensional stability. Further, the transparent film substrate 1 may contain additives such as an antistatic agent, an ultraviolet ray preventing agent, a plasticizer, and a lubricant. Further, in the transparent film substrate 1, the surface on the side where other layers are laminated may be subjected to corona treatment, low temperature plasma treatment, ion bombardment treatment, chemical treatment, solvent treatment, etc. in order to improve adhesion. Good.

  The thickness of the transparent film substrate 1 is not particularly limited. However, in consideration of suitability as a packaging material and workability when other layers are laminated, the thickness is practically in the range of 6 μm to 100 μm. In particular, a range of 9 μm to 25 μm is preferable. Further, the thickness of the base material layer 1 is not particularly limited when used in a surface protection sheet or a back surface protection sheet of a solar cell, or even in electronic paper or an organic EL. In consideration of processing suitability in the subsequent process of the gas barrier laminated film according to the above, it is practically desirable to be in the range of 12 μm to 200 μm, particularly in the range of 12 μm to 125 μm.

  The smoothness of the transparent film substrate 1 is not particularly limited, but is one of the important characteristics for the first gas barrier layer and the second gas barrier layer to exhibit high gas barrier properties. This is because the smoother the surface of the transparent film substrate 1 is, the more dense a gas barrier layer can be formed from the vicinity of the surface, and a uniform film thickness can be easily obtained. It is considered that the arithmetic average roughness Ra indicating the smoothness of the surface is 5 nm or less as a necessary condition for developing a high gas barrier property. However, the gas barrier laminate film of the present invention is characterized in that the film thickness of the first gas barrier layer and the second gas barrier layer is as thin as 1 nm or more and 5 nm or less as described later. Roughness Ra is required to be further smoother than 5 nm or less, and Ra needs to be 1 nm or less.

  In the transparent gas barrier film according to the present invention, the first gas barrier layer is made of an inorganic oxide, and the formation method is not particularly limited, but the first gas barrier layer made of an inorganic oxide has a high gas barrier property. In order to achieve this, vacuum film formation capable of forming a gas barrier layer in a vacuum is suitable. Among these, the vacuum deposition method is the best when laminating at a higher speed.

  In the current vacuum vapor deposition method, the electron source heating method, the resistance heating method, the induction heating method, or the like is preferable as the heating means for the evaporation source material in the vacuum vapor deposition apparatus. In order to improve the adhesion between the transparent film substrate 1 and the second gas barrier layer, it is possible to use a plasma assist method, an ion beam assist method, or the like. Further, in order to improve transparency, reactive vapor deposition may be performed by blowing oxygen gas or the like.

Further, as a method other than the vacuum vapor deposition method, the deposition rate for forming the gas barrier layer is not as fast as the vacuum vapor deposition method, but the plasma CVD method is preferable as a method that easily exhibits higher gas barrier properties. Examples of the plasma generator include low-temperature plasma generators such as direct current (DC) plasma, low frequency plasma, high frequency plasma, pulse wave plasma, tripolar plasma, and microwave plasma.

  In the transparent gas barrier film of the present invention, the first gas barrier layer is not particularly limited as long as it is an inorganic oxide that is transparent and exhibits gas barrier properties. At present, it is desirable to use any composition of silicon oxide, aluminum oxide, titanium oxide, and magnesium oxide as an inorganic oxide that can achieve both transparency and high gas barrier properties against oxygen, water vapor, and the like.

  The thickness of these first gas barrier layers is not less than 1 nm and not more than 5 nm. In general, since the gas barrier property can be improved by increasing the thickness of the gas barrier layer, a thick film is used as one method for improving the gas barrier property in a transparent gas barrier film that requires a high gas barrier property. May be. However, since the gas barrier layer exhibiting high gas barrier properties is a dense film, the flexibility is poor, and it is preferable to make the film thickness as thin as possible in order to keep the gas barrier layer flexible. However, the gas barrier property that is insufficient when the film thickness is reduced is compensated by stacking four or more gas barrier layers and setting the total thickness of all the gas barrier layers to be 10 nm or more.

  For these reasons, the upper limit of the film thickness of the first gas barrier layer is preferably 5 nm or less, although it depends on the method of forming the gas barrier layer and the film composition. As for the lower limit of the film thickness, if the film thickness is less than 1 nm, there are places where the film is not formed, and the function as a gas barrier material cannot be achieved. Therefore, the film thickness is desirably 1 nm or more. As for the film formation method, continuous film formation by a winding method utilizing the characteristics of the transparent film substrate 1 is possible. Therefore, a winding type vacuum deposition film forming apparatus or a winding type plasma CVD film formation method is possible. It is preferable to use an apparatus.

  In the gas barrier laminate film according to this embodiment, the second gas barrier layer is made of silicon oxide represented by the chemical formula SiOxCy (x is 1.5 or more and 2.0 or less, y is 0.2 or more and 0.5 or less). . By controlling the content of the carbon component to be contained, not only the gas barrier property as the second gas barrier layer but also the flexibility is expressed, so the buffer layer is formed between the first gas barrier layers. As an effect. That is, if the y value indicating the carbon content is less than 0.2, the flexibility is insufficient, and if the y value exceeds 0.5, the flexibility is high, but a dense film is obtained. As a result, the gas barrier properties are reduced. Therefore, the y value needs to be 0.2 or more and 0.5 or less, and controlling this y value is one of important points in the transparent gas barrier film of the present invention.

  In the transparent gas barrier film of the present invention, the method for forming the second gas barrier layer is not particularly limited. However, as described above, the y value of the second gas barrier layer represented by SiOxCy is 0.2 or more. In order to make it 0.5 or less, plasma CVD method is preferable at present. Moreover, as a plasma generator, low temperature plasma generators, such as direct current (DC) plasma, low frequency plasma, high frequency plasma, pulse wave plasma, tripolar structure plasma, and microwave plasma, can be considered.

The thickness of the second gas barrier layer is not less than 1 nm and not more than 5 nm. In general, since the gas barrier property can be improved by increasing the thickness of the gas barrier layer, a thick film is used as one method for improving the gas barrier property in a transparent gas barrier film that requires a high gas barrier property. May be. However, since the gas barrier layer exhibiting high gas barrier properties is a dense film, the flexibility is poor, and it is preferable to make the film thickness as thin as possible in order to keep the gas barrier layer flexible. However, for the gas barrier properties that are insufficient by reducing the film thickness, as will be described later, it is possible to stack four or more gas barrier layers and to make the total thickness of all the gas barrier layers to be 10 nm or more. I make up for it.

  For these reasons, the upper limit of the thickness of the second gas barrier layer is preferably 5 nm or less, although it depends on the method of forming the gas barrier layer and the film composition. As for the lower limit value of the film thickness, if the film thickness is less than 1 nm, there is a portion where the film is not formed, and the function as a gas barrier material cannot be achieved. Since the flexibility expected of the gas barrier layer cannot be exhibited, the film thickness is desirably 1 nm or more.

  The second gas barrier layer made of silicon oxide, which is stacked by the plasma CVD method, can be formed using a silane compound having carbon in the molecule and oxygen gas as raw materials, and is formed by adding an inert gas to the raw materials. You can also Examples of silane compounds having carbon in the molecule include tetraethoxysilane (TEOS), tetramethoxysilane (TMOS), tetramethylsilane (TMS), hexamethyldisiloxane (HMDSO), tetramethyldisiloxane, methyltrimethoxy. Relatively low molecular weight silane compounds such as silane are conceivable. One or more of these silane compounds may be selected. Considering the film forming pressure and the vapor pressure, among these silane compounds, TEOS, TMOS, TMS, HMDSO, tetramethylsilane and the like are preferable.

  In film formation by the plasma CVD method, a silane compound vaporized and mixed with oxygen gas is introduced between the electrodes, and plasma is generated by applying power with a low-temperature plasma generator, and is laminated on the surface of the first gas barrier layer. can do. In the plasma CVD method, the film quality of the second gas barrier layer made of silicon oxide can be changed by various methods. For example, changes in the silane compound and gas type, mixing ratio of the silane compound and oxygen gas, increase / decrease in applied power, and the like can be considered.

  In addition, the transparent gas barrier film according to the present invention can be laminated with other films and used in the field of packaging of food, daily necessities, pharmaceuticals, etc., and the fields of solar cell related members and electronic equipment related members. For example, in the packaging field, the transparent gas barrier film according to the present invention may be used as the outermost layer, and an intermediate film layer, a heat seal layer, or the like may be laminated via an adhesive. In addition, a transparent gas barrier film is used in the middle, an outer film layer or the like is laminated on one side of the film with an adhesive, and a heat seal layer or the like is laminated on the other side of the film with an adhesive. May be.

  Examples of intermediate film layer or outer film layer include polyester films such as polyethylene terephthalate and polyethylene naphthalate, polyolefin films such as polyethylene and polypropylene, polyamide films, polycarbonate films, polyacrylonitrile films, polyimide films, etc. A transparent film layer can be considered.

  Examples of heat seal layers include polyethylene, polypropylene, ethylene vinyl acetate copolymer, ethylene / methacrylic acid copolymer, ethylene / methacrylic acid ester copolymer, ethylene / acrylic acid copolymer, ethylene / acrylic acid ester copolymer Synthetic resins such as coalescence and cross-linked products of these metals are used.

The thicknesses of the intermediate film layer, the outer film layer, and the heat seal layer are determined according to the purpose, but are generally in the range of 15 μm to 200 μm. Examples of the adhesive include a one-component curable type or two-component curable polyurethane adhesive. In order to laminate these layers through an adhesive, a dry laminating method or the like can be used. In addition, as another method for laminating the heat seal layer, a method (extrusion lamination) in which the synthetic resin of the heat seal layer is hot melt extruded can be used.

  Hereinafter, although the transparent gas barrier film of the present invention will be described in detail with reference to examples, it is not actually limited to the following examples. In the following Examples 1 and 2, as shown in FIG. 2, the first gas barrier layer 2, the second gas barrier layer 3, and the first gas barrier are formed on one surface of the base material layer 1. A gas barrier laminate film in which the layer 4, the second gas barrier layer 5, the first gas barrier layer 6, and the second gas barrier layer 7 were sequentially laminated was produced.

<Example 1>
A biaxially stretched polyethylene terephthalate (PET) film having a thickness of 25 μm is prepared as the transparent film substrate 1 and is set in a vacuum film forming apparatus, and metal aluminum is evaporated by an electron beam heating method. Oxygen gas was introduced, and a first gas barrier layer 2 made of aluminum oxide having a thickness of 3 nm was laminated on the surface of the transparent film substrate 1.

  Next, in the same vacuum film-forming apparatus, a mixed gas of 5 sccm of hexamethyldisiloxane (HMDSO) / 50 sccm of oxygen is introduced between the electrodes, and a high frequency of 13.56 MHz is applied by 0.5 kW to form plasma. On the surface of the gas barrier layer 2, a second gas barrier layer 3 made of silicon oxide represented by SiOxCy having a thickness of 4 nm was laminated. At this time, the x value was 1.8 and the y value was 0.3.

  Next, in the same vacuum film forming apparatus, metal aluminum is evaporated by an electron beam heating method, oxygen gas is introduced therein, and the surface of the second gas barrier layer 3 is made of aluminum oxide having a thickness of 3 nm. A first gas barrier layer 4 was laminated.

  Next, in the same vacuum film-forming apparatus, a mixed gas of 5 sccm of hexamethyldisiloxane (HMDSO) / 50 sccm of oxygen is introduced between the electrodes, and a high frequency of 13.56 MHz is applied by 0.5 kW to form plasma. On the surface of the gas barrier layer 4, a second gas barrier layer 5 made of silicon oxide represented by SiOxCy having a thickness of 4 nm was laminated. At this time, the x value was 1.8 and the y value was 0.3.

  Next, in the same vacuum film forming apparatus, metal aluminum is evaporated by an electron beam heating method, oxygen gas is introduced therein, and the surface of the second gas barrier layer 5 is made of aluminum oxide having a thickness of 3 nm. A first gas barrier layer 6 was laminated.

  Next, in the same vacuum film-forming apparatus, a mixed gas of 5 sccm of hexamethyldisiloxane (HMDSO) / 50 sccm of oxygen is introduced between the electrodes, and a high frequency of 13.56 MHz is applied by 0.5 kW to form plasma. On the surface of the gas barrier layer 6, a second gas barrier layer 7 made of silicon oxide represented by SiOxCy having a thickness of 4 nm was laminated. At this time, the x value was 1.8 and the y value was 0.3. In this way, a transparent gas barrier film was produced.

<Example 2>
The first gas barrier layer 2 laminated on the surface of the transparent film substrate 1 was evaporated into silicon oxide by an electron beam heating method to form a gas barrier layer made of silicon oxide having a thickness of 3 nm. Furthermore, the first gas barrier layer 4 laminated on the surface of the second gas barrier layer 3 was vaporized by the same electron beam heating method to form a gas barrier layer made of silicon oxide having a thickness of 3 nm. Furthermore, the first gas barrier layer 6 laminated on the surface of the second gas barrier layer 5 was vaporized by the same electron beam heating method to form a gas barrier layer made of silicon oxide having a thickness of 3 nm. Other conditions were the same as in Example 1 to produce a transparent gas barrier film.

<Comparative Example 1>
A biaxially stretched polyethylene terephthalate (PET) film having a thickness of 25 μm is prepared as the transparent film substrate 1 and is set in a vacuum film forming apparatus, and metal aluminum is evaporated by an electron beam heating method. Oxygen gas was introduced, and a first gas barrier layer 2 made of aluminum oxide having a thickness of 9 nm was laminated on the surface of the base material layer 1.

  Next, in the same vacuum film-forming apparatus, a mixed gas of 5 sccm of hexamethyldisiloxane (HMDSO) / 50 sccm of oxygen is introduced between the electrodes, and a high frequency of 13.56 MHz is applied by 0.5 kW to form plasma. On the surface of the gas barrier layer 2, a second gas barrier layer 3 made of silicon oxide represented by SiOxCy having a thickness of 12 nm was laminated to produce a transparent gas barrier film. At this time, the x value was 1.8 and the y value was 0.3.

<Comparative example 2>
When the second gas barrier layer 3, the second gas barrier layer 5 and the second gas barrier layer 7 are laminated, a mixed gas of hexamethyldisiloxane (HMDSO) 5 sccm / oxygen 100 sccm is placed between the electrodes in the vacuum film forming apparatus. Introduced and converted into plasma by applying a high frequency of 13.56 MHz to 0.5 kW, x of the second gas barrier layer 3, the second gas barrier layer 5 and the second gas barrier layer 7 made of silicon oxide represented by the chemical formula SiOxCy The value was 1.9, and the y value was 0.05. Other conditions were the same as in Example 1 to produce a transparent gas barrier film.

<Evaluation and method>
The transparent gas barrier films produced in Examples 1 and 2 and Comparative Examples 1 and 2 were evaluated by the following methods. The results are shown in Table 1 below.
(1) Water vapor permeability in a 40 ° C. 90% RH environment Water vapor permeability (g / m ² ) in a 40 ° C. 90% RH environment using a water vapor permeability meter (MOCON PERMATRAN-W3 / 31) manufactured by Modern Control. -Day) was measured.
(2) Oxygen permeability in an environment of 30 ° C. and 70% RH Oxygen permeability (cc / cc) in an environment of 30 ° C. and 70% RH using an oxygen permeability meter (MOCON OX-TRAN-2 / 21) manufactured by Modern Control. m ² · day) was measured.
(3) Water vapor permeability and oxygen permeability after bending test (Gelbo test) A bending test (Gelbo test) is performed under the following conditions, and the water vapor permeability after the test is performed in the same manner as (1) and (2) above. The measurement was performed in an environment of 40 ° C. and 90% RH, and the oxygen permeability after the test was measured in an environment of 30 ° C. and 70% RH.
≪Bending test conditions≫
・ Bending process: 440 degrees twist x 3.5 inch straight advance + 2.5 inch straight advance ・ Bending number: room temperature x 3 times ・ Sample size: 205 mm x 290 mm

<Comparison result>
As can be seen from Table 1, in Example 1, Example 2, Comparative Example 1, and Comparative Example 2, the water vapor permeability and the oxygen permeability before the bending test (Gelbo test) were at the same level. On the other hand, the transparent gas barrier film of Comparative Example 1 in which the film thickness of the first gas barrier layer 2 and the second gas barrier layer 3 is thicker than 5 nm is compared with the transparent gas barrier film of Example 1 and Example 2. The water vapor permeability and oxygen permeability after the bending test were high, and the gas barrier properties were inferior.

Furthermore, the transparent gas barrier film of Comparative Example 2 in which the y value of the first gas barrier layer made of silicon oxide represented by the chemical formula SiOxCy is smaller than 0.2 is the transparent gas barrier film of Examples 1 and 2. Compared with, the water vapor permeability and oxygen permeability after the bending test were high, and the gas barrier properties were inferior.

  The transparent gas barrier film of the present invention requires particularly high gas barrier properties and flex resistance in the fields of packaging such as foods, daily necessities, and pharmaceuticals, and fields such as solar cell-related members and electronic device-related members. Can be suitably used.

DESCRIPTION OF SYMBOLS 1 ... Transparent film base material 2 ... 1st gas barrier layer 3 ... 2nd gas barrier layer 4 ... 1st gas barrier layer 5 ... 2nd gas barrier layer 6 ... 1st Gas barrier layer 7 ... second gas barrier layer 8 ... transparent gas barrier film 9 ... transparent gas barrier film

Claims (5)

On the transparent film substrate surface, a transparent first gas barrier layer made of a metal oxide, x of silicon oxide represented by the chemical formula SiO _x C _y is 1.5 or more and 2.0 or less, and y of carbon is 0.1. A transparent gas barrier film formed by laminating two or more composite gas barrier layers in this order as a set of a composite gas barrier layer composed of a transparent second gas barrier layer of 2 or more and 0.5 or less, The thickness of one gas barrier layer is 1 nm or more and 3 nm or less, the thickness of the second gas barrier layer is 1 nm or more and 4 nm or less, and the total thickness of the stacked composite gas barrier layers is 10 nm or more. A transparent gas barrier film characterized by being.   The transparent gas barrier film according to claim 1, wherein the second gas barrier layer is formed by a plasma CVD method.   The transparent gas barrier film according to claim 1 or 2, wherein the first gas barrier layer is made of any one of silicon oxide, aluminum oxide, titanium oxide, and magnesium oxide.   The transparent gas barrier film according to claim 1, wherein the first gas barrier layer is formed by a vacuum deposition method. The transparent gas barrier film according to any one of claims 1 to 4, wherein an arithmetic average roughness Ra of a surface on which the first gas barrier layer of the transparent film substrate is formed is 1 nm or less.

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