JP5223598B2 - Method for producing gas barrier sheet - Google Patents

Description

  The present invention relates to a gas barrier sheet and a method for producing the same, and more particularly to a gas barrier sheet having excellent hygroscopicity and thus excellent in gas barrier properties and a method for producing the same.

  Research and development of a gas barrier sheet that exhibits a high gas barrier property by forming an inorganic or organic thin film on a substrate film has been conventionally performed. The gas barrier sheet is used in various applications, and as one of such applications, a sealing film for a display such as an organic EL (Organic Electro-Luminescence) element can be given.

  When a gas barrier sheet is used for a sealing film of a display such as an organic EL element, a high gas barrier performance against water vapor is required for realizing a flexible display or an electronic device. Moreover, even if high gas barrier performance is realized, there is degassing (mainly water vapor) from the sealing material and the base material, and development of a gas barrier sheet having a function of absorbing this gas is also demanded.

  Patent Document 1 discloses that a water vapor barrier film having at least one inorganic gas barrier layer on a polyalkylene naphthalate resin base film has a glass transition point (Tg) of the polyalkylene naphthalate resin within a predetermined range and a predetermined resistance. A water vapor barrier film is described which has at least one conductive layer having. And it is described that the said water vapor | steam barrier film has an at least 2 layer inorganic gas barrier layer, and has a hygroscopic layer which consists of at least one group 2 metal monoxide between inorganic gas barrier layers.

  According to Patent Document 1, the component contained in the inorganic gas barrier layer is particularly preferably a metal oxide selected from Si, Al, Sn, and Ti. In addition, the hygroscopic layer can include a layer composed of a Group 2 metal monoxide, and Mg, Ca, Sr, and Ba are preferable in consideration of cost, availability of high-purity materials, and practicality. From the viewpoint of hygroscopicity and safety, Ca and Sr are preferable, and Sr is most preferable.

  In Patent Document 2, a substrate, a pair of electrodes formed on one surface of the substrate, interposed between the pair of electrodes, and electrons and positive electrodes supplied from these electrodes are arranged. An organic electroluminescent portion including at least an organic light emitting layer that emits light through the holes, a sealing member made of a predetermined transparent substrate, and a predetermined moisture absorbing moisture in the space between the substrate and the sealing member An electrode directed to the sealing member is made of a transparent conductive material, and the porous material layer has an organic electric field so that the light emitted from the organic light emitting layer does not cause a moire phenomenon in the space. An organic EL display is described that is spaced a predetermined distance from the light emitting section.

  According to Patent Document 2, the porous material layer is made of a transparent material, and this material absorbs moisture in the internal space of the sealing member. In addition, the porous material layer may be formed of a porous oxide having a plurality of moisture absorption holes so that the transparency can be maintained even after moisture is absorbed. Furthermore, the porous oxide forming material for forming the porous material layer includes (i) porous silica, (ii) hydrated amorphous alumina, (iii) hydrated amorphous alumina and porous silica, (Iv) 1 selected from the group consisting of hydrated amorphous alumina and alkali metal oxides, alkaline earth metal oxides, metal halides, metal sulfates and metal perchlorates A mixture of two or more components, (v) hydrated amorphous alumina, porous silica, alkali metal oxide, alkaline earth metal oxide, metal halide, metal sulfate and metal perchlorine One or more selected from the group consisting of acid salts and a multi-component mixture of three or more components can be exemplified.

JP 2006-239883 A (Claims 1, 7, 0017 paragraph, 0021 paragraph, 0023 paragraph, 0023 paragraph, 0027 paragraph, 0113 paragraph, 0114 paragraph, and 0131 paragraph) Japanese Patent No. 4001590 (Claim 1, Paragraph 0049, Paragraph 0051, Paragraph 0058)

  In Patent Document 1, it is considered that the sputtering method is the most desirable as the method for forming the hygroscopic layer, and the sputtering method is also used in the examples. In Patent Document 2, as a method for producing a porous material layer, after coating a predetermined mixture, it is aged at room temperature for about 24 hours or at 40 to 50 ° C. for about 5 hours, and then 400 ° C. to form moisture absorption holes. The polymer is heated by baking in an oven for about 2 hours.

  However, according to the study of the present inventor, it has been found that the above method does not necessarily provide a hygroscopic layer excellent in hygroscopicity. That is, according to the study of the present inventor, as a result of applying the vacuum film forming method as it is or processing at a high temperature when forming the hygroscopic layer, the layer structure (for example, density) of the hygroscopic layer does not become favorable. It has been found that the surface roughness of the hygroscopic layer, and thus the gas barrier sheet, becomes very large due to an increase in film stress and cracking of the hygroscopic layer. It has been found that a moisture absorbing layer having such a layer structure cannot provide a gas barrier sheet having good moisture absorption characteristics and consequently gas barrier characteristics. As described above, it has been found that the conventional manufacturing method of the hygroscopic layer has a problem that a hygroscopic layer having a good layer structure and good hygroscopic properties cannot be obtained.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a gas barrier sheet having a hygroscopic layer excellent in hygroscopicity and a method for producing the same.

  As a result of intensive studies on the method of forming the moisture-absorbing layer, the inventor maintains a low temperature state during the formation of the moisture-absorbing layer, more specifically, by keeping the temperature lower than room temperature (25 ° C.), It has been found that the moisture absorption layer is not easily fragile, has a good layer structure, and has a highly flat moisture absorption layer. As a result, it has been found that a gas barrier sheet having excellent moisture absorption characteristics and thus excellent gas barrier properties can be obtained, and the present invention has been completed.

  The gas barrier sheet of the present invention for solving the above problems is a gas barrier sheet having a base material and a hygroscopic layer provided on the base material, wherein the hygroscopic layer is an alkali metal oxide or An alkaline earth metal oxide is contained, and the maximum height difference (Rmax) of the surface of the gas barrier sheet is 1000 nm or less.

  According to this invention, the hygroscopic layer contains an alkali metal oxide or an alkaline earth metal oxide, and the maximum height difference (Rmax) of the surface of the gas barrier sheet is 1000 nm or less, so that the hygroscopic layer has a good layer structure. As a result, a gas barrier sheet having a hygroscopic layer excellent in hygroscopicity can be provided.

  In a preferred embodiment of the gas barrier sheet of the present invention, the alkaline earth metal oxide is at least one selected from the group consisting of magnesium oxide, strontium oxide, and barium oxide.

  According to this invention, since the alkaline earth metal oxide is at least one selected from the group consisting of magnesium oxide, strontium oxide, and barium oxide, a material having good moisture absorption characteristics is used for the moisture absorption layer. As a result, it becomes easy to make hygroscopicity better.

  In another preferred embodiment of the gas barrier sheet of the present invention, the arithmetic average roughness (Ra) of the surface of the gas barrier sheet is 1 nm or more, and the maximum height difference (Rmax) is 30 nm or more.

  According to this invention, since the arithmetic mean roughness (Ra) of the surface of the gas barrier sheet is 1 nm or more and the maximum height difference (Rmax) is 30 nm or more, it is possible to obtain a moisture absorbing layer having an appropriate surface roughness. As a result, it becomes easy to make the moisture absorption property better.

  In another preferred embodiment of the gas barrier sheet of the present invention, the gas barrier sheet has a total light transmittance of 80% or more and a yellowness (YI) of 5 or less.

  According to this invention, since the total light transmittance of the gas barrier sheet is 80% or more and the yellowness (YI) is 5 or less, it becomes a gas barrier sheet with good transparency, and as a result, the gas barrier sheet of the present invention. Can be easily applied to a display application such as an organic EL element.

  In another preferred embodiment of the gas barrier sheet of the present invention, a gas barrier layer is provided between the substrate and the moisture absorbing layer.

  According to this invention, since the gas barrier layer is provided between the base material and the hygroscopic layer, the gas barrier sheet can be further provided with gas barrier properties (for example, moisture and oxygen blocking properties), and as a result, the hygroscopic property. And it becomes easier to obtain a gas barrier sheet having excellent gas barrier properties.

  The method for producing a gas barrier sheet of the present invention for solving the above-described problem is the method for producing a gas barrier sheet of the present invention, wherein the moisture absorbent layer is formed at a temperature lower than room temperature (25 ° C.). It has the process.

  According to this invention, since it has a hygroscopic layer forming step of forming the hygroscopic layer at a temperature lower than room temperature (25 ° C.), a hygroscopic layer having a good layer structure can be obtained, and as a result, the hygroscopic property is excellent. The manufacturing method of the gas barrier sheet | seat which has a moisture absorption layer can be provided.

  In a preferred embodiment of the method for producing a gas barrier sheet of the present invention, the hygroscopic layer is formed at a temperature of 0 ° C. or lower.

  According to this invention, since the hygroscopic layer is formed at a temperature of 0 ° C. or less, the layer structure of the hygroscopic layer is easily made better, and as a result, it becomes easy to obtain a hygroscopic layer with better hygroscopic properties.

  In another preferred embodiment of the method for producing a gas barrier sheet of the present invention, the moisture absorbing layer is formed by a vacuum film forming method.

  According to the present invention, since the moisture absorption layer is formed by a vacuum film formation method, high temperature particles tend to be deposited on the film formation surface and the layer structure of the moisture absorption layer tends to be brittle. By cooling and forming at a temperature lower than room temperature (25 ° C.), the significance of controlling the layer structure of the hygroscopic layer is increased, and as a result, a hygroscopic layer having a good layer structure can be easily obtained.

  In another preferred embodiment of the method for producing a gas barrier sheet of the present invention, the vacuum film forming method is an ion plating method or an electron beam evaporation method.

  According to this invention, since the vacuum film formation method is an ion plating method or an electron beam evaporation method, high energy particles tend to deposit on the film formation surface and the layer structure of the moisture absorption layer tends to be more fragile. Therefore, it is more meaningful to control the layer structure of the moisture absorption layer by cooling the film formation surface or the like and forming it at a temperature lower than room temperature (25 ° C.). As a result, the moisture absorption layer having a good layer structure It will be easier to get.

  In another preferred embodiment of the method for producing a gas barrier sheet of the present invention, a hygroscopic layer surface treatment step for treating the surface of the hygroscopic layer is provided after the hygroscopic layer formation step.

  According to the present invention, after the moisture absorption layer forming step, since it has a moisture absorption layer surface treatment step for treating the surface of the moisture absorption layer, the surface roughness of the moisture absorption layer can be increased to increase the surface area. As a result, the moisture absorption characteristics are more likely to be improved.

  In another preferable aspect of the method for producing a gas barrier sheet according to the present invention, the surface treatment of the moisture absorbing layer in the moisture absorbing layer surface treatment step includes an oxygen plasma method, an atmospheric pressure plasma method, a dry etching method, and a glow discharge method. Done by either.

  According to the present invention, the surface treatment of the moisture absorbing layer in the moisture absorbing layer surface treatment step is performed by any one of the oxygen plasma method, the atmospheric pressure plasma method, the dry etching method, and the glow discharge method. And it becomes possible to perform the surface treatment as a whole in a vacuum, and as a result, it becomes easier to improve the productivity of the gas barrier sheet.

  ADVANTAGE OF THE INVENTION According to this invention, the gas barrier sheet | seat which has a moisture absorption layer excellent in moisture absorption can be provided.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the gas barrier sheet | seat which has a moisture absorption layer excellent in moisture absorption can be provided.

  Next, embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the gist of the present invention.

[Gas barrier sheet]
FIG. 1 is a schematic cross-sectional view showing an example of the gas barrier sheet of the present invention. The gas barrier sheet 1A has a substrate 2 and a moisture absorbing layer 3 provided on the substrate 2, and the moisture absorbing layer 3 contains an alkali metal oxide or an alkaline earth metal oxide, and has a gas barrier property. The maximum height difference (Rmax) of the surface of the sheet 1A is 1000 nm or less. Thereby, it becomes the moisture absorption layer 3 which has a favorable layer structure, As a result, the gas barrier sheet 1A having the moisture absorption layer 3 having excellent moisture absorption can be provided. In the gas barrier sheet 1 </ b> A, the moisture absorbing layer 3 is provided in contact with the substrate 2, but other layers may be appropriately provided between the substrate 2 and the moisture absorbing layer 3. .

  In the gas barrier sheet 1A, the maximum height difference (Rmax) of the surface of the gas barrier sheet is controlled to 1000 nm or less while using an alkali metal oxide or an alkaline earth metal oxide for the moisture absorption layer 3. Specifically, as will be described later, when the hygroscopic layer is formed, the layer structure of the hygroscopic layer is controlled by forming it at a temperature lower than room temperature (25 ° C.) to ensure the predetermined surface roughness. doing. The specific method for controlling the temperature lower than room temperature during film formation will be described below in terms of the manufacturing method described later, and the surface roughness of the gas barrier sheet 1A can be controlled by film formation at a low temperature. Will be explained.

  The moisture absorption layer contains an alkali metal oxide or an alkaline earth metal oxide. The present inventor has examined the mechanism of film formation of such a moisture absorption layer, and it is preferable that the moisture absorption layer contains as little moisture as possible immediately after the film formation. Is preferably carried out at a high temperature. From such a viewpoint, conventionally, a hygroscopic layer has been formed by a vacuum film forming method such as a sputtering method or a method of firing after applying and drying the composition. However, as a result of further studies by the inventor, it has been observed that the moisture absorption layer tends to be brittle due to high-temperature film formation, and in some cases, the moisture absorption layer cracks and the surface of the moisture absorption layer becomes rough. I found out that Further, it was found that even when the crack of the moisture absorption layer was not observed, the deterioration of the surface roughness, which seems to be caused by the microscopic crack of the moisture absorption layer accompanying the film formation at a high temperature, was observed. These phenomena are presumed to be due to an increase in the film stress of the hygroscopic layer. Although the cause of the observation of such a phenomenon is unknown, it is presumed that there is a cause in the growth method of the material when the film is formed. That is, when alkali metal oxide or alkaline earth metal oxide is used as the material of the moisture absorption layer, these materials tend to grow in islands on the film formation surface (the surface of the substrate 2 in FIG. 1). It seems. The island-like growth is presumed to be due to the affinity for the film formation surface and the strength of the bonding force between the materials, but when the film is formed at a high temperature, the bonding force between the materials becomes stronger, It seems that the bonding strength of each of the islands growing on the film formation surface becomes stronger (the density tends to increase). However, on the other hand, it seems that the bonding strength between adjacent island regions tends to be weak. Therefore, it is thought that the tendency for the moisture absorption layer to become brittle appears as a result of the weakening of the bonding strength between the adjacent island regions.

  From the above viewpoint, it is preferable that the moisture absorption layer 3 contains as little moisture as possible immediately after film formation, but it is necessary to suppress deterioration of surface roughness due to fragility. From this point of view, it is necessary to control the deterioration of the surface roughness that is presumed to be caused by cracks or microscopic cracks that accompany the moisture absorption layer 3 becoming brittle. For this reason, the maximum height difference (Rmax) on the surface of the moisture absorbing layer 3 and thus the gas barrier sheet 1A is set to 1000 nm or less, preferably 700 nm or less, more preferably 500 nm or less. Further, from the same viewpoint and prevention of peeling due to the fragility of the moisture absorption layer 3, the arithmetic average roughness (Ra) of the surface of the gas barrier sheet 1A is preferably 30 nm or less, more preferably 20 nm or less, More preferably, it is 15 nm or less. Regarding the surface roughness of the gas barrier sheet 1A (moisture absorbing layer 3), as described later, it is preferable that the surface of the moisture absorbing layer 3 is surface-treated to be slightly rough from the viewpoint of moisture absorption characteristics. However, the surface roughness is controlled to be within the range. As described above, in the present invention, the hygroscopic layer 3 is formed at a low temperature in order to improve the layer structure of the hygroscopic layer 3 and control the surface roughness of the gas barrier sheet 1A within a predetermined range. However, the means for controlling the surface roughness is not limited to this, and other appropriate methods for controlling the surface roughness are used in place of or in combination with the above-described method of forming the hygroscopic layer 3 at a low temperature. be able to.

  Another parameter related to the layer structure (film quality) of the hygroscopic layer 3 is a refractive index. That is, as described above, when a film is formed at a high temperature, it seems that a tendency that the bonding force of each island growing on the film formation surface is increased (density increases) is observed. Therefore, when film formation is performed at a high temperature, the density of the moisture absorption layer 3 tends to increase and the refractive index tends to increase. From such a viewpoint, it is preferable to reduce the refractive index by suppressing the density of the moisture absorption layer 3. Specifically, the refractive index of the moisture absorption layer 3 is preferably 1.8 or less, more preferably 1.6 or less, further preferably 1.5 or less, and 1.45 or less. It is particularly preferable to set it to 1.4 or less. On the other hand, the refractive index is usually 1.2 or more, preferably 1.3 or more, more preferably 1.35 or more.

  The refractive index in the moisture absorption layer 3 can be measured by a conventionally known method, for example, an ellipsometer. In the present invention, the refractive index is measured by UVISELTM manufactured by JOBIN YVON. The measurement is performed using a xenon lamp as a light source, an incident angle of −60 °, a detection angle of 60 °, and a measurement range of 1.5 eV to 5.0 eV.

  The moisture absorption layer 3 contains an alkali metal oxide or an alkaline earth metal oxide. Although there is no restriction | limiting in particular as an alkali metal oxide, It is preferable to use sodium oxide and potassium oxide from viewpoints, such as stability and moisture absorption performance. The alkaline earth metal oxide is not particularly limited, but is preferably at least one selected from the group consisting of magnesium oxide, strontium oxide, and barium oxide. As a result, a material having good hygroscopic properties is used for the hygroscopic layer 3, and as a result, the hygroscopic property is easily improved. Although the moisture absorption layer 3 may contain materials (for example, additives and impurities) other than alkali metal oxides and alkaline earth metal oxides, it is formed of alkali metal oxides or alkaline earth metal oxides. It is preferable. Of the alkaline earth metal oxides, strontium oxide or barium oxide is more preferably used, and strontium oxide is more preferably used from the viewpoint of further improving moisture absorption characteristics. However, since Ba used for barium oxide is a deleterious substance, it must be handled with care.

  The thickness of the hygroscopic layer 3 is usually 1 nm or more, preferably 5 nm or more, more preferably 10 nm or more, from the viewpoint of ensuring a predetermined hygroscopicity. Further, from the viewpoint of ensuring productivity, ensuring the layer structure, etc., it is usually 1000 nm or less, preferably 500 nm or less, more preferably 300 nm or less.

  It is preferable that the surface of the moisture absorbing layer 3 and the gas barrier sheet 1A has an arithmetic average roughness (Ra) of 1 nm or more and a maximum height difference (Rmax) of 30 nm or more. Thereby, the moisture absorption layer which has moderate surface roughness can be obtained, As a result, it becomes easy to make a moisture absorption characteristic more favorable. Ra is preferably 3 nm or more, more preferably 5 nm or more, and Rmax is preferably 40 nm or more, more preferably 50 nm or more. As a result of improving the layer structure by forming the hygroscopic layer 3 at a low temperature, the hygroscopic layer 3 and thus the surface roughness of the gas barrier sheet 1A can be reduced. In the present invention, the hygroscopic properties are further improved. From this point of view, it is also preferable to control the moisture absorption layer 3 to the above numerical range by surface-treating the surface slightly rough. Details of the surface treatment of the moisture absorption layer 3 will be described later.

  For the measurement of Ra and Rmax on the surface of the hygroscopic layer 3 (gas barrier sheet 1A), a conventionally known method may be appropriately used. In the present invention, an atomic force microscope (AFM), Nanopics-1000 manufactured by Seiko Instruments Inc. is used, and in accordance with JIS B0601, arithmetic mean roughness (Ra) and in the range of 10 μm. The maximum protrusion length (Rmax) is measured.

  A method for forming the moisture absorption layer 3 will be described later.

  Next, the base material 2 used for the gas barrier sheet 1A will be described. Various base materials can be used as the base material 2, and mainly a sheet shape, a film shape, or a take-up roll shape is used. However, depending on a specific application or purpose, a non-flexible substrate is used. Alternatively, a flexible substrate can be used. For example, non-flexible substrates such as glass substrates, hard resin substrates, wafers, printed substrates, various cards, resin sheets, etc. may be used. For example, polyethylene terephthalate (PET), polyamide, polyolefin, polyethylene naphthalate (PEN) Using flexible substrates such as polycarbonate, polyacrylate, polymethacrylate, polyurethane acrylate, polyethersulfone, polyimide, polysilsesquioxane, polynorbornene, polyetherimide, polyarylate, amorphous cyclopolyolefin, cellulose triacetate Also good. In the case where the substrate 2 is made of resin, the resin exemplified above may be appropriately mixed and used as the resin to be used. Moreover, when the base material 2 is resin, what has heat resistance of 100 degreeC or more preferably 150 degreeC or more is suitable suitably.

  As such a resin base material 2, specifically, an amorphous cyclopolyolefin resin film (for example, ZEONEX (registered trademark) or ZEONOR (registered trademark) of Nippon Zeon Co., Ltd., ARTON of JSR Corporation, etc.), Polycarbonate film (for example, Teijin Kasei Co., Ltd. Pure Ace), polyethylene terephthalate film (for example, Teijin Kasei Co., Ltd.), cellulose triacetate film (for example, Konica Minolta Opto Konica Katak KC4UX, KC8UX, etc.) And commercially available products such as polyethylene naphthalate film (for example, Teonex (registered trademark) of Teijin DuPont Films Ltd.).

  The thickness of the substrate 2 is usually 10 μm or more, preferably 50 μm or more, and usually 200 μm or less, preferably 150 μm or less, from the viewpoints of flexibility and shape retention.

  When the base material 2 is used as a substrate of a light emitting element such as an organic EL display that requires transparency, the base material 2 is preferably colorless and transparent. By making the other films such as the moisture absorption layer 3 colorless and transparent together with the base material 2, the gas barrier sheet 1A can be made transparent. More specifically, for example, it is preferable that the substrate 2 has a transparency with an average light transmittance of 80% or more within a range of 400 nm to 700 nm. Since such light transmittance is influenced by the material and thickness of the base material 2, both are considered.

  The surface of the substrate 2 is preferably smooth. Specifically, the arithmetic average roughness (Ra) of the surface of the substrate 2 is usually set to 0.3 nm or more. If it is this range, moderate surface roughness can be provided to the base material 2, and when the base material 2 is used as a take-up roll, slippage hardly occurs on the contact surfaces of the base materials 2 that are in contact with each other. The arithmetic average roughness (Ra) of the surface of the substrate 2 is usually 100 nm or less, preferably 50 nm or less, more preferably 30 nm or less. If it is this range, the smoothness of the base material 2 will improve and it will become easy to exhibit the advantage which can suppress the short circuit which may generate | occur | produce when producing display elements, such as an organic EL display. The arithmetic average roughness (Ra) may be measured according to JIS B 0601-2001 (based on ISO 4287-1997).

  It is preferable that the base material 2 is not easily deformed by heat. This is because when the gas barrier sheet 1A is applied to an organic EL display, it is required that the gas barrier sheet 1A is not deformed even by heating / cooling stress such as a heat cycle test. Specifically, the linear expansion coefficient of the base material 2 is usually 5 ppm / ° C. or more, usually 80 ppm / ° C. or less, preferably 50 ppm / ° C. or less. The linear expansion coefficient may be measured using a conventionally known method, for example, a TMA method (thermomechanical analysis method). As a measuring apparatus used for the TMA method, for example, Rigaku CN8098F1 which is a differential expansion type thermomechanical analyzer can be used.

  When a resin-made material is used as the substrate 2, the production method thereof can also be produced by a conventionally known general method. Moreover, when using resin-made base material 2, you may use a stretched film. The stretching method may be a conventionally known general method. Although a draw ratio can be suitably selected according to resin used as the raw material of the base material 2, it is preferable to set it as 2-10 times in a vertical axis direction and a horizontal axis direction, respectively.

  The surface of the substrate 2 is subjected to surface treatment such as corona treatment, flame treatment, plasma treatment, glow discharge treatment, roughening treatment, heat treatment, chemical treatment, UV irradiation treatment, atmospheric pressure plasma treatment, and easy adhesion treatment. May be. As a specific method of such surface treatment, a conventionally known method can be appropriately used.

  FIG. 2 is a schematic cross-sectional view showing another example of the gas barrier sheet of the present invention. In the gas barrier sheet 1 </ b> B, the gas barrier layer 4 is provided between the substrate 2 and the moisture absorption layer 3 provided on the substrate 2. That is, the gas barrier sheet 1 </ b> B is provided with the gas barrier layer 4 between the base material 2 and the moisture absorption layer 3. Thereby, gas barrier property (for example, moisture and oxygen barrier properties) can be further imparted to the gas barrier sheet 1B, and as a result, the gas barrier sheet 1B having excellent hygroscopicity and gas barrier properties can be obtained more easily. That is, if oxygen, moisture, or the like to enter the gas barrier sheet 1B through the base material 2 is primarily blocked by the gas barrier layer 4 and the moisture that still enters is secondarily captured by the moisture absorbing layer 3. It becomes easy to ensure higher gas barrier performance as the gas barrier sheet 1B. In the gas barrier sheet 1 </ b> B, the gas barrier layer 4 is provided in contact with the substrate 2, but other layers may be appropriately provided between the substrate 2 and the gas barrier layer 4. . Further, in the gas barrier sheet 1B, the moisture absorption layer 3 is provided on the gas barrier layer 4, but another layer may be appropriately provided between the gas barrier layer 4 and the moisture absorption layer 3. .

  Since the base material 2 and the moisture absorption layer 3 used for the gas barrier sheet 1B may be the same as those of the gas barrier sheet 1A shown in FIG. 1, the description here is omitted to avoid duplication of explanation.

The gas barrier layer 4 has gas barrier properties that function to block moisture, oxygen, and the like. Examples of the material used for the gas barrier layer 4 include oxides such as silicon oxide, aluminum oxide, magnesium oxide, indium oxide, calcium oxide, zirconium oxide, titanium oxide, boron oxide, hafnium oxide, barium oxide, tin oxide, and zinc oxide. A nitride such as silicon nitride, aluminum nitride, boron nitride, and magnesium nitride; a carbide such as silicon carbide, a sulfide, and the like. Moreover, you may use 2 or more types of composite_body | complex chosen from them. Examples of such composites include composite oxides using two or more oxides, composite metal oxynitrides using two or more oxides and nitrides, inorganic oxynitrides containing oxygen and nitrogen, and carbon Inorganic oxide carbides, inorganic nitride carbides, inorganic oxynitride carbides, etc., containing More specifically, inorganic oxide (MO _x ), inorganic nitride (MN _y ), inorganic carbide (MC _z ), inorganic oxide carbide (MO _x C _z ), inorganic nitride carbide (MN _y C _z ), inorganic Among oxynitrides (MO _x N _y ) and inorganic oxynitride carbides (MO _x N _y C _z ), preferable M is a metal element such as Si, Al, or Ti. Among them, a film made of M and Si and made of silicon oxide is preferably used because it has high transparency and good gas barrier properties, whereas silicon nitride exhibits higher gas barrier properties. Particularly preferred is a composite of silicon oxide and silicon nitride (inorganic oxynitride (SiO _x N _y )). When the content of silicon oxide is large, the transparency is improved, and when the content of silicon nitride is large, the gas barrier property is improved. Moreover, since the easy to ensure the flexibility and adhesion of the layer by the inclusion of carbon, it is also preferable to use an inorganic oxide carbide (SiO x _{C z).} In addition, examples of composite oxides using two or more oxides include MaMbO _x and MaMbMcO _x . Furthermore, examples of the composite metal oxynitride using two or more kinds of oxides and nitrides include MaMbO _x N _y and MaMbMcO _x N _y . Here, Ma, Mb, and Mc represent different metal elements, and examples thereof include Sn, Zn, Si, Al, and Ti. Further, the gas barrier layer 4 may contain a predetermined amount of predetermined additives and impurities in addition to the above-described materials.

  The thickness of the gas barrier layer 4 is usually 10 nm or more, preferably 30 nm or more, and usually 200 nm or less, preferably 150 nm or less. When the thickness of the gas barrier layer 4 is within the above range, it is easy to ensure the gas barrier property and also to ensure the productivity.

  A method for forming the gas barrier layer 4 will be described later.

  As described above, the gas barrier sheets 1A and 1B have been described as specific examples of the gas barrier sheet 1. However, the layer configuration of the gas barrier sheet 1 is not limited to these specific examples, and variations relating to lamination are within the scope of the gist of the present invention. It can be performed appropriately. Specifically, in addition to the substrate 2, the moisture absorption layer 3, and the gas barrier layer 4, for example, a transparent conductive layer that functions as an electrode, a hard coat layer that has a protective function against scratches, and the like, and has heat dissipation Examples include a heat dissipation layer, an antireflection layer, an antistatic layer, and an antifouling layer. Among these, the antireflection layer, the antistatic layer, and the antifouling layer may be bonded to the gas barrier sheet 1 via an adhesive.

  The gas barrier sheet 1 preferably has a total light transmittance of 80% or more and a yellowness (YI) of 5 or less. Thereby, it becomes the gas barrier property sheet 1 with favorable transparency, and as a result, it becomes easy to apply the gas barrier property sheet 1 to a use of a display such as an organic EL element. From the viewpoint of ensuring higher transparency, the total light transmittance is more preferably 90% or more, and YI is more preferably 2 or less.

  The total light transmittance and YI of the gas barrier sheet 1 can be measured by appropriately using a conventionally known method. In the present invention, the total light transmittance and YI are measured using an SM color computer SM-C (manufactured by Suga Test Instruments). ing. The measurement is performed according to JIS K7105.

  The gas barrier sheet 1 can be used for various devices. Examples of such devices include solar cells, liquid crystal displays, OLED (Organic light-emitting diode) displays, and OLED lighting.

[Method for producing gas barrier sheet]
The method for producing a gas barrier sheet of the present invention includes a hygroscopic layer forming step of forming the hygroscopic layer at a temperature lower than room temperature (25 ° C.). Thereby, the moisture absorption layer which has a favorable layer structure can be obtained, and as a result, the manufacturing method of the gas barrier sheet | seat which has a moisture absorption layer excellent in moisture absorption can be provided.

  As described above, the method for producing a gas barrier sheet of the present invention includes a hygroscopic layer forming step, but other steps may be appropriately selected and used depending on the layer structure of the gas barrier sheet to be produced. Specifically, when manufacturing the gas barrier sheet 1A having the layer structure of the substrate 2 / the moisture absorption layer 3 shown in FIG. 1, the substrate preparation step → the moisture absorption layer forming step → (if necessary, the surface of the moisture absorption layer When a gas barrier sheet 1B having a layer structure of base material 2 / gas barrier layer 4 / moisture absorption layer 3 shown in FIG. 2 is manufactured, the base material preparation step → Manufacture is performed through a gas barrier layer forming step → a hygroscopic layer forming step → (performing a hygroscopic layer surface treatment step if necessary). What is necessary is just to select the process used in this way suitably. Therefore, each step will be described below.

(Base material preparation process)
The base material preparation step is a step of preparing a base material. About the manufacturing method of a base material, in the detailed description about the base material 2 shown in FIG. 1, it is as having demonstrated the case where the resin-made base materials 2 are used as an example. Therefore, in order to avoid duplication of explanation, explanation here is omitted.

(Hygroscopic layer forming step)
The hygroscopic layer forming step is a step of forming the hygroscopic layer at a temperature lower than room temperature (25 ° C.). The formation of the hygroscopic layer at a low temperature results in a good layer structure, and as a result, a hygroscopic layer (gas barrier sheet) having a predetermined surface roughness can be obtained as described above. That is, by forming the film at a low temperature, it is easy to suppress the film stress and prevent the moisture absorption layer from cracking. And the effect that it becomes easy to improve the film-forming speed | rate (productivity), promoting the island-like growth of a thin film is also show | played.

  In the hygroscopic layer forming step, the hygroscopic layer is preferably formed at a temperature of 10 ° C. or lower, more preferably 5 ° C. or lower, still more preferably 0 ° C. or lower, and particularly preferably −5 ° C. or lower. Thereby, it becomes easy to make the layer structure of a moisture absorption layer more favorable, As a result, it becomes easy to obtain the moisture absorption layer with a more favorable moisture absorption characteristic. The lower the formation temperature of the hygroscopic layer, the better. However, in consideration of actual use, the temperature during the formation of the hygroscopic layer is usually −30 ° C. or higher.

  The cooling method in the hygroscopic layer forming step is not particularly limited. For example, a metal plate is installed on the back surface of the base material, a coolant is allowed to flow inside the metal plate, and the metal plate is cooled with cold air to form the hygroscopic layer. Temperature control may be performed. When forming the moisture-absorbing layer, it is preferable to control the substrate temperature and the like so that the moisture-absorbing layer is stably formed at a constant temperature.

  In the hygroscopic layer forming step, the hygroscopic layer is preferably formed by a vacuum film forming method. As a result, high temperature particles tend to be deposited on the film formation surface and the layer structure of the moisture absorption layer tends to be brittle. Therefore, the film formation surface and the like are cooled to form a temperature lower than room temperature (25 ° C.) This increases the significance of controlling the layer structure of the moisture absorption layer, and as a result, it becomes easier to obtain a moisture absorption layer having a good layer structure. More specifically, when the gas barrier sheet 1A shown in FIG. 1 is manufactured, the hygroscopic layer 3 is directly provided on the substrate 2, but when the vacuum film forming method is used, the hygroscopic layer 3 is provided. Therefore, the particles constituting the hygroscopic layer 3 are rapidly cooled when they are deposited by cooling the substrate 2. This suppresses the moisture absorption layer 3 from becoming brittle. Further, when the gas barrier sheet 1B shown in FIG. 2 is manufactured, the hygroscopic layer 3 is provided directly on the gas barrier layer 4, but the substrate 2 and the gas barrier are formed in the same manner as in the manufacture of the gas barrier sheet 1A. The layer structure of the moisture absorption layer 3 is controlled by cooling the laminate with the layer 4.

  In the hygroscopic layer forming step, when the hygroscopic layer is formed by a vacuum film forming method, the vacuum film forming method is preferably an ion plating method or an electron beam evaporation method. As a result, high energy particles tend to be deposited on the film formation surface and the layer structure of the moisture absorption layer tends to be more fragile. Therefore, the film formation surface or the like is cooled to a temperature lower than room temperature (25 ° C.). By forming, the significance of controlling the layer structure of the hygroscopic layer becomes greater, and as a result, it becomes easier to obtain a hygroscopic layer having a good layer structure.

  The ion plating method is a combined technique of vacuum vapor deposition and plasma, and is a method of forming a thin film by activating a part of evaporated particles as ions or excited particles using gas plasma in principle. In the ion plating method, reactive ion plating in which a reactive gas plasma is combined with evaporated particles to synthesize a compound film is effective. Since the operation is in plasma, the first condition is to obtain a stable plasma. In many cases, low-temperature plasma using weakly ionized plasma in a low gas pressure region is used. For this reason, it is preferably used when a mixture or a complex oxide is formed. The means for generating a discharge is roughly classified into a direct current excitation type and a high frequency excitation type. In addition, a hollow cathode or an ion beam may be used for the evaporation mechanism. As described above, in the ion plating method, the vapor deposition particles (particles constituting the hygroscopic layer) are irradiated with plasma, and the vapor deposition particles tend to have high energy, so that moisture in the vapor deposition particles can be easily removed while high temperature is high. The layer structure of the hygroscopic layer tends to be fragile. For this reason, it becomes easy to exhibit the effect of the cooling at the time of moisture absorption layer formation more notably.

  The electron beam evaporation method is a method of forming a solid thin film on a film formation surface by irradiating an electron beam to vapor deposition particles and evaporating the particles. As the electron beam evaporation method, a conventionally known method can be used. Even in the electron beam evaporation method, the vapor deposition particles (particles constituting the moisture absorption layer) are irradiated with an electron beam, and the vapor deposition particles tend to have high energy. It becomes a film and the layer structure of the hygroscopic layer tends to be fragile. For this reason, it becomes easy to exhibit the effect of the cooling at the time of moisture absorption layer formation more notably.

  In the hygroscopic layer forming step, when the hygroscopic layer is formed by using the vacuum film forming method, it is necessary to finally release the vacuum to return to the atmospheric pressure. In this case, it is preferable to adopt a method of returning to atmospheric pressure while replacing with an inert gas (for example, nitrogen or argon) from the viewpoint of maintaining and ensuring the moisture absorption characteristics of the moisture absorption layer. Thereby, when returning to atmospheric pressure, it becomes easy to suppress that a moisture absorption layer absorbs the moisture in the air.

(Hygroscopic layer surface treatment process)
In the method for producing a gas barrier sheet of the present invention, it is preferable to have a moisture absorption layer surface treatment step for treating the surface of the moisture absorption layer after the moisture absorption layer forming step. Thereby, the surface roughness of the moisture absorption layer can be increased to increase the surface area, and as a result, the moisture absorption characteristics can be improved more easily. More specifically, the apparent adsorption amount can be increased by increasing the surface area. In addition, the surface treatment tends to increase the moisture absorption rate.

  The surface treatment of the moisture absorbing layer in the moisture absorbing layer surface treatment step is not particularly limited, but is preferably performed by any one of an oxygen plasma method, an atmospheric pressure plasma method, a dry etching method, and a glow discharge method. As a result, the film formation and surface treatment of the hygroscopic layer can be performed in a vacuum, and as a result, the productivity of the gas barrier sheet can be further improved. The conditions of the oxygen plasma method, the atmospheric pressure plasma method, the dry etching method, and the glow discharge method may be appropriately controlled according to the film quality of the moisture absorption layer. Specifically, the hygroscopic layer tends to be brittle, so the surface treatment conditions are set weak, such as weakening the power, increasing the pressure, decreasing the flow rate of argon, and adjusting the processing time. It is preferable. Other than these conditions, conventionally known methods can be appropriately employed.

(Gas barrier layer formation process)
In the gas barrier layer forming step, a gas barrier layer is formed. The formation of the gas barrier layer is not particularly limited, but usually a vacuum film forming method is used. As such a vacuum film forming method, for example, a vacuum deposition method, a sputtering method, an ion plating method, a Cat-CVD method, a plasma CVD method, an atmospheric pressure plasma CVD method, or the like may be used. Such a formation method may be selected in consideration of the type of film forming material, easiness of film formation, process efficiency, and the like. Some of these forming methods are described below.

  The vacuum deposition method is a method for obtaining a gas barrier layer by heating and evaporating the material contained in the crucible by resistance heating, high frequency induction heating, beam heating such as an electron beam or an ion beam, and attaching the material to a substrate or the like. . At that time, the heating temperature and the heating method can be changed depending on the composition of the gas barrier layer, and a reactive vapor deposition method that causes an oxidation reaction or the like during film formation can also be used.

  Sputtering is a method in which a target is placed in a vacuum chamber, a high-voltage ionized rare gas element (usually argon) is collided with the target, and atoms on the target surface are ejected to adhere to the substrate, This is a method for obtaining a gas barrier layer. At this time, a reactive sputtering method in which a gas barrier layer is formed by reacting an element ejected from the target with nitrogen or oxygen by flowing nitrogen gas or oxygen gas into the chamber may be used. Examples of the sputtering method include DC dipolar sputtering, RF dipolar sputtering, tripolar and quadrupolar sputtering, ECR sputtering, ion beam sputtering, and magnetron sputtering. Industrially, magnetron sputtering is used. preferable.

  The general description of the ion plating method is as described in the hygroscopic layer forming step.

  The plasma CVD method is a kind of chemical vapor deposition method. In the plasma CVD method, raw materials are vaporized and supplied during plasma discharge, and the gases in the system are mutually activated and radicalized by collision. Therefore, reactions at low temperatures that are impossible only by thermal excitation are possible. It becomes possible. The substrate or the like is heated from behind by a heater, and a film is formed by a reaction during discharge between the electrodes. It is classified into HF (several tens to hundreds of kHz), RF (13.56 MHz), and microwave (2.45 GHz) depending on the frequency used for generating plasma. When microwaves are used, the method is broadly divided into a method of exciting a reaction gas and forming a film in an afterglow, and an ECR plasma CVD in which microwaves are introduced into a magnetic field (875 Gauss) that satisfies the ECR condition. Further, when classified by the plasma generation method, it is classified into a capacitive coupling method (parallel plate type) and an inductive coupling method (coil method).

  The composition of the gas barrier layer can be controlled by appropriately changing the manufacturing conditions while appropriately using the manufacturing method introduced above.

(Other processes)
In the method for producing a gas barrier sheet of the present invention, in addition to the substrate preparation process, the hygroscopic layer forming process, the hygroscopic layer surface treatment process, and the gas barrier layer forming process described above, depending on the laminated structure employed for the gas barrier sheet, These steps can be used. For example, when a transparent conductive layer is provided, a transparent conductive layer forming step may be further performed.

  As described above, according to the present invention, it is possible to provide a method for producing a gas barrier sheet having a hygroscopic layer excellent in hygroscopicity.

  EXAMPLES Next, although an Example demonstrates this invention further more concretely, this invention is not limited to description of a following example, unless the summary is exceeded.

[Example 1]
(Manufacture of gas barrier sheet)
<Base material preparation process>
As the substrate, a polyethylene naphthalate film (Teonex (registered trademark) Q65F, manufactured by Teijin DuPont Films Ltd.) having a thickness of 100 μm was used.

<Hygroscopic layer forming step>
The substrate was placed on a metal plate, and a moisture absorption layer (strontium oxide) having a thickness of 70 nm was formed by an ion plating method under the following film formation conditions while cooling the metal plate. At this time, the surface temperature of the substrate was controlled to be −10 ° C.
Raw material: Strontium oxide Reaction gas: Ar 30 sccm, Oxygen 50 sccm
Power: 300W
Pressure: 0.1Pa

<Hygroscopic layer surface treatment process>
Next, the surface of the moisture absorption layer was treated with oxygen plasma under the following conditions.
RF power supply: 1kW
Oxygen flow rate: 5 sccm
Argon flow rate: 10 sccm
Pressure: about 10Pa
Processing time: 1 minute

(Measurement of refractive index of moisture absorption layer)
The gas barrier sheet thus obtained was measured for the refractive index of the hygroscopic layer. The refractive index was measured using an ellipsometer. Specifically, the refractive index was measured by UVISEL ™ manufactured by JOBIN YVON. The measurement was performed using a xenon lamp as a light source, an incident angle of −60 °, a detection angle of 60 °, and a measurement range of 1.5 eV to 5.0 eV. As a result, the refractive index of the moisture absorption layer was 1.35.

(Measurement of surface roughness of moisture absorption layer)
For the surface roughness of the moisture absorption layer, an arithmetic force roughness (AFM: Atomic Force Microscope) using Nanopics-1000 manufactured by Seiko Instruments Inc. in the range of 10 μm in accordance with JIS B0601 ( Ra) and the maximum protrusion length (Rmax) were measured. As a result, Ra was 8 nm and Rmax was 342 nm.

(Measurement of water vapor transmission rate)
The water vapor transmission rate was measured using a water vapor transmission rate measurement apparatus (manufactured by MOCON, USA, PERMATRAN-W 3/31: trade name) under the conditions of a measurement temperature of 37.8 ° C. and a humidity of 100% Rh. In addition, although the detection limit of the water vapor transmission rate measuring apparatus used for the measurement is 0.05 g / m ² · day, when the water vapor transmission rate is measured, it is 0.05 g / m ² · day or less than the detection limit. Met. The water vapor transmission rate was measured after the gas barrier sheet immediately after production was kept in a desiccator for 1 day.

(Measurement of oxygen permeability)
The oxygen permeability was measured using an oxygen gas permeability measuring device (manufactured by MOCON, USA, OX-TRAN 2/20: trade name) under the conditions of a measurement temperature of 23 ° C. and a humidity of 90% Rh. The detection limit of the oxygen gas permeability measuring device used for the measurement is 0.05 cc / m ² · day · atm, but when the oxygen permeability was measured, it was 0.05 cc / m ² · day · atm. It was below the detection limit. The oxygen permeability was also measured after holding the gas barrier sheet immediately after production in a desiccator for 1 day.

(Measurement of total light transmittance and color (YI))
The total light transmittance and YI of the gas barrier sheet were measured using SM color computer SM-C (manufactured by Suga Test Instruments). The measurement was performed according to JIS K7105. As a result, the total light transmittance was 85.3% and YI was 0.7.

[Example 2]
In the hygroscopic layer forming step, a gas barrier sheet was produced in the same manner as in Example 1 except that the temperature of the substrate surface was controlled to be 0 ° C. Various characteristics were measured in the same manner as in Example 1. The results are shown below.

Refractive index of moisture absorption layer: 1.38
Surface roughness of the hygroscopic layer: Ra is 7 nm, Rmax is 315 nm
Water vapor transmission rate: 0.05g ^/ m 2 · day at the detection limit or less oxygen ^{permeability: 0.05cc / m 2 · day ·} atm at a detection limit or less total light transmittance: 83.5%
Y1: 0.5

[Comparative Example 1]
In the hygroscopic layer forming step, a gas barrier sheet was produced in the same manner as in Example 1 except that the temperature of the substrate surface was controlled to be 25 ° C. When the moisture absorption layer after film formation was observed, cracks were observed on the surface. Various characteristics of the produced gas barrier sheet were measured in the same manner as in Example 1. The results are shown below.

Refractive index of moisture absorbing layer: 1.42
Surface roughness of the hygroscopic layer: Ra is 31 nm, Rmax is 1100 nm
Water vapor transmission rate: 1.5 g / m ² · day
Oxygen permeability: 0.5cc / m ² · day · atm
Total light transmittance: 84.1%
Y1: 0.8

[Comparative Example 2]
In the hygroscopic layer forming step, a gas barrier sheet was produced in the same manner as in Example 1 except that the temperature of the substrate surface was controlled to be 80 ° C. When the moisture absorption layer after film formation was observed, cracks were observed on the surface and coloring was also observed. Various characteristics of the produced gas barrier sheet were measured in the same manner as in Example 1. The results are shown below.

Refractive index of moisture absorbing layer: 1.45
Surface roughness of the hygroscopic layer: Ra is 35 nm, Rmax is 1500 nm
Water vapor transmission rate: 3.5 g / m ² · day
Oxygen permeability: 3.2 cc / m ² · day · atm
Total light transmittance: 83.0%
Y1: 1.0

[Example 3]
A gas barrier sheet was produced in the same manner as in Example 1 except that the hygroscopic layer surface treatment step was not performed. Various characteristics were measured in the same manner as in Example 1. The results are shown below.

Refractive index of moisture absorption layer: 1.40
Surface roughness of the hygroscopic layer: Ra is 5 nm, Rmax is 50 nm
Water vapor transmission rate: 0.08 g / m ² · day
Oxygen permeability: 0.07 cc / m ² · day · atm
Total light transmittance: 85.1%
Y1: 0.2

[Example 4]
(Manufacture of gas barrier sheet)
<Base material preparation process>
Same as Example 1.

<Hygroscopic layer forming step>
A substrate was placed on a metal plate, and a moisture absorption layer (barium oxide) having a thickness of 15 nm was formed by an ion plating method under the following film formation conditions while cooling the metal plate. At this time, the surface temperature of the substrate was controlled to be −10 ° C.
Raw material: Barium oxide Reaction gas: Ar 10 sccm, Oxygen 30 sccm
Power: 300W
Pressure: 0.1Pa

<Hygroscopic layer surface treatment process>
Next, the surface of the moisture absorption layer was treated with atmospheric pressure plasma under the following conditions.
RF power supply: 0.5kW
Oxygen flow rate: 5 sccm
Argon flow rate: 10 sccm
Pressure: 1atm
Processing time: 5 minutes

  Various characteristics of the gas barrier sheet thus obtained were measured in the same manner as in Example 1. The results are shown below.

Refractive index of moisture absorbing layer: 1.42
Surface roughness of the hygroscopic layer: Ra is 12 nm, Rmax is 65 nm
Water vapor transmission rate: 0.05g ^/ m 2 · day at the detection limit or less oxygen ^{permeability: 0.05cc / m 2 · day ·} atm at a detection limit or less total light transmittance: 84.5%
Y1: 0.5

[Example 5]
(Manufacture of gas barrier sheet)
<Base material preparation process>
Same as Example 1.

<Gas barrier layer formation process>
A gas barrier layer (SiOC) having a thickness of 80 nm was formed on the substrate by plasma CVD under the following film formation conditions.
Raw material: HMDSO (hexamethylenesiloxane) 1 slm
Reaction gas: Ar 1 slm, ammonia 0.5 slm
Power: 1kW
Pressure: 10Pa

<Hygroscopic layer forming step>
Next, the substrate / gas barrier layer laminate was placed on the metal plate, and a moisture absorption layer (magnesium oxide) having a thickness of 50 nm was formed by an ion plating method under the following film formation conditions while cooling the metal plate. . At this time, the surface temperature of the substrate was controlled to be −10 ° C.
Raw material: Magnesium oxide Reaction gas: Ar 30 sccm, oxygen 0.5 slm
Power: 250W
Pressure: 0.15Pa

<Hygroscopic layer surface treatment process>
Subsequently, the surface of the moisture absorption layer was processed by dry etching under the following conditions.
RF power supply: 3kW
Argon flow rate: 20 sccm
Pressure: 10Pa
Processing time: 3 minutes

  Various characteristics of the gas barrier sheet thus obtained were measured in the same manner as in Example 1. The results are shown below.

Refractive index of moisture absorption layer: 1.44
Surface roughness of the hygroscopic layer: Ra is 10 nm, Rmax is 125 nm
Water vapor transmission rate: 0.1 g / m ² · day
Oxygen permeability: 0.1 cc / m ² · day · atm
Total light transmittance: 80.1%
Y1: 0.8

It is a typical sectional view showing an example of the gas barrier sheet of the present invention. It is typical sectional drawing which shows another example of the gas barrier sheet | seat of this invention.

Explanation of symbols

1, 1A, 1B Gas barrier sheet 2 Base material 3 Hygroscopic layer 4 Gas barrier layer

Claims (10)

A substrate, have a, a moisture absorption layer provided on the base material, the moisture layer contains an alkali metal oxide or an alkaline earth metal oxide, the maximum height difference of the surface of the gas barrier sheet (Rmax) is a gas gas barrier sheet manufacturing method is 1000nm or less,
A method for producing a gas barrier sheet, comprising a hygroscopic layer forming step of forming the hygroscopic layer at a temperature lower than room temperature (25 ° C.). The method for producing a gas barrier sheet according to claim 1, wherein the alkaline earth metal oxide is at least one selected from the group consisting of magnesium oxide, strontium oxide, and barium oxide. The method for producing a gas barrier sheet according to claim 1 or 2, wherein the arithmetic average roughness (Ra) of the surface of the gas barrier sheet is 1 nm or more, and the maximum height difference (Rmax) is 30 nm or more. The method for producing a gas barrier sheet according to any one of claims 1 to 3, wherein the gas barrier sheet has a total light transmittance of 80% or more and a yellowness (YI) of 5 or less. The manufacturing method of the gas barrier sheet of any one of Claims 1-4 which provides a gas barrier layer between the said base material and the said moisture absorption layer. The moisture absorption layer is formed at 0 ℃ temperatures below the gas barrier sheet manufacturing method according to any one of claims 1 to 5. The moisture absorption layer is formed by a vacuum deposition method, gas barrier sheet manufacturing method according to any one of claims 1-6. The method for producing a gas barrier sheet according to claim 7 , wherein the vacuum film-forming method is an ion plating method or an electron beam evaporation method. The method for producing a gas barrier sheet according to any one of claims 1 to 8 , further comprising a hygroscopic layer surface treatment step of treating the surface of the hygroscopic layer after the hygroscopic layer formation step. The gas barrier sheet according to claim 9 , wherein the surface treatment of the moisture absorbing layer in the moisture absorbing layer surface treatment step is performed by any one of an oxygen plasma method, an atmospheric pressure plasma method, a dry etching method, and a glow discharge method. Production method.

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