JP6635033B2 - Water vapor permeability evaluation method and water vapor permeability evaluation device - Google Patents

Description

  The present invention relates to a water vapor permeability evaluation method and a water vapor permeability evaluation device. More specifically, the present invention relates to a water vapor permeability evaluation method for simultaneously evaluating the water vapor permeability of a gas barrier film or the like and the in-plane variation of the water vapor permeability.

  Conventionally, a gas barrier film in which a thin film (a gas barrier layer) containing a metal oxide such as aluminum oxide, magnesium oxide, or silicon oxide is formed on the surface of a plastic substrate or film prevents deterioration due to various gases such as water vapor and oxygen. It is widely used for the purpose of packaging articles that need to shut off various gases for the purpose. In addition to the above-mentioned packaging applications, it is also used for sealing electronic devices such as solar cells, liquid crystal display devices, and organic electroluminescence devices (hereinafter, also referred to as organic EL devices) in order to prevent deterioration due to various gases. It is used. The gas barrier film is excellent in flexibility as compared with a glass substrate, and is advantageous in terms of roll-type production suitability, weight reduction and handleability of an electronic device.

  However, a film substrate made of a transparent plastic or the like has a problem that gas barrier properties are inferior to glass substrates. When a substrate having poor gas barrier properties is used, there is a problem that water vapor and oxygen permeate, for example, deteriorating functions in an electronic device.

As a method of evaluating gas barrier properties, the evaluation of water vapor permeability conventionally used is a cup method (JIS Z 0208-1976), a so-called Mocon method (JIS K 7129-1992 B method), or the like. Among these methods, the water vapor permeability even wider MOCON method of measurable range in the range of ^{5 × 10 -2 ~5 × 10 3} g / m 2 / 24h are subject. However, a liquid crystal substrate, an organic EL substrate, and the like are required to have even higher evaluation of water vapor permeability.

  As a method for evaluating the gas barrier properties of a gas barrier film, in addition to the above method, a calcium corrosion method for measuring the water vapor permeability (hereinafter, also referred to as a calcium method or a Ca method) is known (for example, non-patented). Reference 1).

  Also, methods related to the calcium corrosion method disclosed in Patent Documents 1 and 2 are known. These methods use a water vapor permeability evaluation cell in which a metal layer that reacts with moisture and corrodes is formed on one side of a gas barrier film by a vacuum process, and this surface is sealed with a water vapor impermeable metal. By taking a reflection image of a corroded film sample, and calculating the number of corroded points per unit area, corroded area, corroded color tone, etc., it is calculated from the corroded area of corroded metal and the thickness of corrosive metal layer. This is a method for quantitatively evaluating the amount of water that reacts with the metal from the volume of the metal corrosive.

  These calcium corrosion methods can measure the water vapor permeability with higher sensitivity than the conventional Mokon method or the like, but do not consider how much the metal layer is corroded in the thickness direction at a predetermined time. . In addition, these methods focus on evaluating the water vapor permeability and defect distribution of the entire gas barrier film as a bulk, and do not mention the variation of the water vapor permeability in the gas barrier film plane.

JP 2004-333127 A JP 2005-181300 A

SVC-47th Annual Technical Conference Proceedings, P654 (2004)

  The present invention has been made in view of the above problems and circumstances, and a solution to the problem is a water vapor permeability evaluation method for simultaneously evaluating the water vapor permeability of a gas barrier film and the like and the in-plane variation of the water vapor permeability, and An object of the present invention is to provide a water vapor permeability evaluation device for performing the evaluation method.

  In order to solve the above-mentioned problems, the present inventor, in the course of examining the cause of the above-mentioned problems, uses a water vapor permeability evaluation cell formed of a corrosive metal that reacts with moisture to form a corrosive metal. When evaluating the degree of water vapor, a new method for evaluating water vapor permeability that can simultaneously measure the water vapor permeability in the plane of the gas barrier film and the variation in the water vapor permeability by an evaluation method including a specific step was found.

  That is, the above object according to the present invention is solved by the following means.

1. A method for evaluating water vapor transmission rate using a corrosive metal that corrodes by reacting with moisture, comprising at least the following steps (1) to ( 7 ).
(1) A step of producing a water vapor permeability evaluation cell in which a moisture impermeable substrate, a corrosive metal layer which is corroded by reacting with water, and an evaluation sample are provided in this order.
(2) a step of measuring a change in optical characteristics of the corrosive metal layer by irradiating light from one surface side of the water vapor permeability evaluation cell before and after the exposure to water vapor.
(3) The designated area of the corrosive metal layer is divided into a fixed unit area having a surface area within a range of 0.01 to ³ mm ² into a predetermined number of divisions equal to or more than 10 equal parts, and corresponding to each other. Measuring the amount of change in the optical characteristics of each part.
(4) calculating the volume of the corroded portion from the amount of change in the optical characteristics obtained in the measurement, and calculating the water vapor permeability based on the volume.
(5) calculating an average value and a standard deviation based on the water vapor permeability of each portion obtained in the step (4).
(6) In the step (3), the specified area of the corrosive metal layer is further divided equally by changing the unit area by at least two kinds, and the mutually corresponding portions are divided in a plurality of division numbers. Measuring the amount of change in the optical characteristics of the above, calculating the average value and the standard deviation in steps (4) and (5), and confirming the accuracy of the calculated value.

  2. The first step is that the step (2) is a step in which light is incident from one surface side of the water vapor permeability evaluation cell and an image is obtained by photographing transmitted light emitted from the opposite surface. The water vapor permeability evaluation method described in the section.

3. 3. The method for evaluating water vapor permeability according to claim 1, wherein the surface area of the corrosive metal layer is 1 cm ² or more.

4. The steam according to any one of claims 1 to 3, wherein a plurality of the steam permeability evaluation cells are used so that the total surface area of the corrosive metal layer is 10 cm ² or more. Transmittance evaluation method.

5 . 2. The step (1), wherein the evaluation sample and the moisture-impermeable substrate are bonded to each other with a light-curable adhesive or a thermosetting adhesive to produce a water vapor permeability evaluation cell. 5. The method for evaluating water vapor transmission rate according to any one of items 4 to 4 .

6 . A water vapor permeability evaluation device that performs the water vapor permeability evaluation method according to any one of Items 1 to 6 ,
Means for irradiating the illumination light from one side of the water vapor permeability evaluation cell from an oblique direction or a normal direction,
Means for measuring either reflected light from the water vapor permeability evaluation cell or transmitted light emitted from the opposite surface,
The specified range of the corrosive metal layer is divided into a fixed unit area having a surface area within a range of 0.01 to ³ mm ² into a predetermined number of divisions equal to or more than 10 and divided into corresponding portions. Means for calculating the area and thickness of the corroded portion by analyzing the data from the amount of change in the optical characteristics of the
Means for calculating the water vapor permeability and the variation of the water vapor permeability from the area and thickness of the obtained corroded portion,
A water vapor permeability evaluation device comprising:

  By the above means of the present invention, it is possible to provide a water vapor permeability evaluation method for simultaneously evaluating the water vapor permeability of a gas barrier film or the like and the in-plane variation of the water vapor permeability, and a water vapor permeability evaluation apparatus for performing the evaluation method. it can.

  In an electronic device such as a flexible organic EL element, it is necessary to use a gas barrier film having a high gas barrier property against water vapor, and an increase in water vapor permeability due to defects in the gas barrier film causes deterioration of the electronic device. Leads to. The conventional method of evaluating water vapor permeability by the calcium corrosion method measures only the water vapor permeability of the entire film, whereas the method of the present invention, in addition to the evaluation of the water vapor permeability of the entire film, It is possible to simultaneously evaluate the water vapor transmission rate and the in-plane variation of the water vapor transmission rate, and it is possible to more accurately and quantitatively evaluate the quality of the gas barrier property of the gas barrier film by the evaluation.

Schematic diagram of the water vapor permeability evaluation cell according to the present invention Schematic configuration diagram showing an example of a water vapor permeability evaluation system according to the present invention Schematic configuration diagram showing another example of the water vapor permeability evaluation system according to the present invention FIG. 1 is a block diagram showing a main configuration of a water vapor permeability evaluation system according to the present invention. Flow chart showing the flow of the water vapor permeability calculation process Examples measured by the water vapor permeability evaluation method of the present invention

The water vapor permeability evaluation method of the present invention is a water vapor permeability evaluation method using a corrosive metal that reacts and corrodes with moisture, and includes at least the above steps (1) to ( 7 ). This feature is a technical feature common to the inventions according to claims 1 to 6 .

  In the present invention, when measuring and analyzing the change in the optical property of the corrosive metal layer, in addition to the entire part, the part is further subdivided, and the amount of change in the optical property for each part is calculated. The method further includes a step of analyzing the data, calculating the water vapor permeability of the site from the data, and calculating a variation in the water vapor permeability. According to the method of the present invention, for example, it is possible to evaluate the water vapor permeability of the entire gas barrier film as an evaluation sample, and the variation of the water vapor permeability of a minute area and the water vapor permeability of the area, and the quality of the gas barrier property can be more accurately determined. Good quantitative evaluation is possible.

  As an embodiment of the present invention, from the viewpoint of manifesting the effect of the present invention, the step (2) includes the step of: transmitting light from one surface side of the water vapor permeability evaluation cell and transmitting light from the opposite surface. Is preferable in that the corroded thickness of the corrosive metal layer can be accurately evaluated and the calculation accuracy of the volume of the metal reacted with water vapor is improved.

Further, in the present invention, in order to further increase the measurement accuracy, the plurality of the water vapor permeability evaluation cells are set so that the surface area of the corrosive metal layer is 1 cm ² or more, and the total surface area is 10 cm ² or more. And that the equally divided surface area of the corrosive metal layer divided into ten or more equal parts is in the range of 0.01 to ³ mm ² .

  Further, in the step (3), the specified area of the corrosive metal layer is equally divided by changing the unit area by at least two kinds, and the optical characteristics of the mutually corresponding portions in a plurality of division numbers are divided. It is a preferred embodiment that the method includes a step of measuring a change amount of the above, calculating an average value and a standard deviation in the steps (4) and (5), and confirming the accuracy of the calculated value.

  In the step (1), the evaluation sample and the moisture-impermeable substrate may be bonded to each other with a light-curable adhesive or a thermosetting adhesive to form a water vapor permeability evaluation cell. It is preferable from the viewpoint of balancing the transparency of the evaluation cell and the sealing of the corrosive metal layer.

The water vapor permeability evaluation apparatus for performing the water vapor permeability evaluation method of the present invention includes: means for irradiating illumination light from one side of the water vapor permeability evaluation cell with an oblique direction or a normal direction; means for measuring any of the transmitted light emitted from the surface of the reflected light or the opposite side of the cell, the range of the specified corrosive metal layer, the surface area each in the range of from 0.01～3Mm ² Means for dividing an area into a certain number of divisions equal to or greater than 10 in a certain unit area, and analyzing the data of the corroded part from the amount of change in the optical characteristics of each part corresponding to each other to calculate the area and thickness; Means for calculating the water vapor permeability from the obtained area and film thickness of the corroded portion, and calculating an average value and a standard deviation.

  Hereinafter, the present invention, its components, and embodiments and modes for carrying out the present invention will be described in detail. In addition, in this application, "-" is used in the meaning including the numerical value described before and after it as a lower limit and an upper limit.

<< Outline of the water vapor permeability evaluation method of the present invention >>
The water vapor permeability evaluation method of the present invention is a method for evaluating water vapor permeability using a corrosive metal that corrodes by reacting with water, and includes at least the following steps (1) to ( 6 ).
(1) A step of producing a water vapor permeability evaluation cell in which a moisture impermeable substrate, a corrosive metal layer which is corroded by reacting with water, and an evaluation sample are provided in this order.
(2) a step of measuring a change in optical characteristics of the corrosive metal layer by irradiating light from one surface side of the water vapor permeability evaluation cell before and after the exposure to water vapor.
(3) The designated area of the corrosive metal layer is divided into a fixed unit area having a surface area within a range of 0.01 to ³ mm ² into a predetermined number of divisions equal to or more than 10 equal parts, and corresponding to each other. Measuring the amount of change in the optical characteristics of each part.
(4) calculating the volume of the corroded portion from the amount of change in the optical characteristics obtained in the measurement, and calculating the water vapor permeability based on the volume.
(5) calculating an average value and a standard deviation based on the water vapor permeability of each portion obtained in the step (4).
(6) In the step (3), the specified area of the corrosive metal layer is further divided equally by changing the unit area by at least two kinds, and the mutually corresponding portions are divided in a plurality of division numbers. Measuring the amount of change in the optical characteristics of the above, calculating the average value and the standard deviation in steps (4) and (5), and confirming the accuracy of the calculated value.

  With such a configuration, in addition to the water vapor transmission rate of the entire evaluation sample, the water vapor transmission rate of the minute area and the variation of the water vapor transmission rate of the area are simultaneously evaluated, and the quality of the gas barrier property of the evaluation sample is more accurately quantified by the evaluation. It can be evaluated.

  For example, in the gas barrier film, it is desirable that, in addition to the low water vapor permeability of the entire film, the in-plane variation of the water vapor permeability is small. Although the conventional method of evaluating water vapor transmission rate has been aimed at exclusively evaluating the water vapor transmission rate of the entire film, according to the evaluation method of the present invention, in addition to the water vapor transmission rate of the entire film, the in-plane water vapor transmission rate Can easily be evaluated, so that the quality of the gas barrier property can be quantitatively evaluated with higher accuracy. Therefore, the water vapor permeability evaluation method of the present invention can be a powerful evaluation method for supporting the design of a gas barrier film.

<Configuration of water vapor permeability evaluation method of the present invention>
The water vapor permeability evaluation method of the present invention uses a water vapor permeability evaluation cell having a corrosive metal to at least perform the steps (1) to (5) to reduce the water vapor permeability of a gas barrier film and the like and the variation of the water vapor permeability. This is an evaluation method of water vapor permeability to be evaluated.

The water vapor permeability evaluation apparatus of the present invention is an apparatus capable of sequentially performing the above-mentioned steps (1) to ( 6 ), and is an oblique direction or a normal to one surface of the water vapor permeability evaluation cell. Means for irradiating illumination light from the direction, means for measuring either reflected light from the water vapor permeability evaluation cell or transmitted light emitted from the opposite surface, and a specified range of the corrosive metal layer. Is divided into a certain number of divisions equal to or more than 10 in a certain unit area having a surface area within a range of 0.01 to ³ mm ² , and the corroded portion is determined from the amount of change in the optical characteristics of each corresponding portion. It is preferable to include a means for calculating the area and the thickness by analyzing the data of the above, and a means for calculating the water vapor permeability and the variation of the water vapor permeability from the obtained area and thickness of the corroded portion.

[1] Method for Evaluating Water Vapor Permeability Hereinafter, details of each step will be described.

(1) Step of Producing a Water Vapor Permeability Evaluation Cell This step is to prepare a water vapor permeability evaluation cell in which a moisture impermeable substrate, a corrosive metal layer which reacts with water to corrode, and an evaluation sample are provided in this order. It is a step to do.

  The water vapor permeability evaluation cell according to the present invention (hereinafter, also simply referred to as an evaluation cell) has a corrosive metal layer (hereinafter, also simply referred to as a corrosive metal layer) that reacts with moisture and corrodes therein. .

  FIG. 1 is a schematic diagram showing an example of the water vapor permeability evaluation cell according to the present invention.

  The water vapor permeability evaluation cell F first forms a corrosive metal layer 2 that reacts with water and corrodes on a water impermeable substrate 1.

  The moisture-impermeable substrate 1 according to the present invention is preferably transparent and does not transmit moisture, and is preferably a glass substrate. For example, soda lime glass, silicate glass and the like can be mentioned, and silicate glass is preferable, and specifically, silica glass or borosilicate glass is more preferable. The thickness of the glass substrate is in the range of 0.1 to 2 mm, and it is preferable that the glass substrate is transparent from the viewpoint of not introducing noise when taking an image with transmitted light.

  The corrosive metal according to the present invention is a metal that constitutes a metal layer that is corroded by reacting with moisture, and is preferably a metal whose optical characteristics change.

  Specifically, an alkali metal, an alkaline earth metal or an alloy thereof is preferable, and examples thereof include an alkali metal such as lithium and potassium, and an alkaline earth metal such as calcium, magnesium, and barium. Among them, calcium is preferably inexpensive and relatively easy to form a deposited film.

  Calcium changes to calcium hydroxide by causing a chemical bond with water, and changes from silver to transparent. For example, the degree of corrosion can be analyzed by measuring the change in the light reflectance, light transmittance, or luminance value of calcium, and the water vapor permeability can be measured.

  The formation of the corrosive metal layer 2 is not limited by vapor deposition or coating, but is preferably vapor deposition from the viewpoint of workability and control of the layer thickness. For example, it is performed as follows. Using a vacuum deposition apparatus having a metal deposition source, a metal that reacts with water and corrodes is vapor-deposited on the moisture-impermeable substrate 1 to be evaluated by masking a part other than a part to be vapor-deposited. The use of a vacuum evaporation apparatus is preferable because the corrosive metal layer can be sealed by the adhesive layer 3 as a sealing material described later without being exposed to the atmosphere after the evaporation. Further, the corrosive metal layer 2 may be provided on the evaluation sample 6.

  The thickness of the corrosive metal layer is preferably in the range of 10 to 500 nm. It is preferable that the thickness of the metal layer that is corroded by reacting with moisture formed by vapor deposition be 10 nm or more, because the metal layer is uniformly formed on the moisture-impermeable substrate 1. On the other hand, when the thickness is 500 nm or less, when sealing with an adhesive, the step between the portion where the metal layer that reacts with water and corrodes and the portion where the metal layer is not formed is reduced, so that the boundary portion is reduced. This is preferable because peeling and sealing defects are less likely to occur.

In the step (3) to be described later, the formation surface area of the corrosive metal layer divides the designated area of the corrosive metal layer into a fixed unit area, each of which is divided into a fixed number of equal to or more than 10 equal parts, and corresponds to each other. from the viewpoint of measuring the amount of change in the optical properties of each part that is preferably at 1 cm ² or more, more preferably in the range of 1～1000Cm ^2, in a range of 1～500Cm ² More preferred.

In actual measurement, from the viewpoint of accurately evaluating the water vapor transmission rate of the entire evaluation sample, a plurality of the water vapor transmission rate evaluation cells are provided so that the total surface area of the corrosive metal layer to be evaluated is 10 cm ² or more. It is preferable to obtain the average value of the obtained water vapor permeability.

  After the formation of the corrosive metal layer 2, the mask is removed, and before exposure to the atmosphere, the adhesive layer 3 is sealed with a light-curable adhesive-containing layer or a thermosetting adhesive-containing layer, and then an evaluation sample Laminate with 6.

  The adhesive used for the adhesive layer 3 is not particularly limited, and those usually used as adhesives and pressure-sensitive adhesives, for example, acrylic pressure-sensitive adhesives, rubber-based pressure-sensitive adhesives, polyurethane-based pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives and the like can be used. A photo-curable or thermo-curable adhesive having a reactive vinyl group of an acrylic acid-based oligomer or a methacrylic acid-based oligomer; a thermosetting or chemically curable (two-component mixture) adhesive such as an epoxy-based adhesive; a hot melt Polyamide, polyester, polyolefin, cation-curable ultraviolet-curable epoxy resin adhesive, and the like can be preferably used.

  In the present invention, it is preferable to use an adhesive processed into a sheet.

  When a sheet-type adhesive is used, an adhesive that exhibits non-fluidity at room temperature (about 25 ° C.) and exhibits fluidity at a temperature in the range of 50 to 120 ° C. when heated is used. .

  The thickness of the adhesive layer is not particularly limited and is appropriately selected depending on the use of the adhesive sheet, but is preferably in the range of 0.5 to 100 μm, more preferably in the range of 1 to 60 μm, and still more preferably. It is in the range of 3 to 40 μm. From the viewpoint of adhesive strength, the thickness is preferably 0.5 μm or more, and if it is 100 μm or less, the influence of moisture from the sealing end can be reduced.

The water vapor transmission rate of the adhesive layer at a thickness of 50 μm is preferably 25 g / m ² / day or less, more preferably 10 g / m ² / day or less, and still more preferably 8 g in an atmosphere at 40 ° C. and a relative humidity of 90%. / M ² / day or less. If the water vapor transmission rate is 25 g / m ² / day or less, it is possible to prevent water from entering from the end.

  The light transmittance of the adhesive is preferably 80% or more, more preferably 85% or more, even more preferably 90% or more in total light transmittance. If the total light transmittance is less than 80%, the loss of the incident light increases, which hinders the evaluation. The total light transmittance can be measured according to JIS K 7375: 2008 “Plastics—How to determine total light transmittance and total light reflectance”.

  Although the evaluation sample 6 is not particularly limited, a gas barrier film may be mentioned as a sample to which the present invention can be preferably applied, and the gas barrier layer 5 formed on the base film 4 as the gas barrier film may be a In the evaluation cell according to the invention, it is preferable that the evaluation cell is disposed on the surface side of the corrosive metal layer 2.

  Hereinafter, the present application will be described on the assumption that a gas barrier film is used as an evaluation sample.

  In addition, in order to suppress the influence of moisture and the like remaining in the adhesive and the gas barrier film, it is preferable that the water vapor permeability evaluation cell be pretreated. In particular, in the case of a Ca cell structure in which the adhesive and the corrosive metal come into direct contact, the residual moisture content of the adhesive is preferably in the range of 0 to 2000 ppm, and more preferably in the range of 10 to 1000 ppm. .

  When it is larger than this range, the influence of the reaction between the corrosive metal and the moisture of the adhesive becomes large, and the evaluation is hindered. On the other hand, when it is small, it takes an extremely long processing time, which is not practical. As a method for measuring the residual water content, a known method such as the Karl Fischer method or the GC-MASS method can be used.

  In addition, since the residual moisture content may vary depending on the location and the corrosive metal part of the produced Ca cell may be uneven, it is preferable to perform the pretreatment even when the residual moisture content is within a predetermined range. .

The pretreatment is performed by exposing to a vacuum or a low moisture concentration environment. The treatment temperature and time may be appropriately determined depending on the heat resistance of the film and the heat resistance and curing conditions of the adhesive. For example, in a room temperature environment, it is desirable to expose to a vacuum or a low moisture concentration environment for 4 hours or more.
(2) a step of measuring a change in the optical properties of the corrosive metal layer Step (2) includes, before and after exposure to water vapor, light incident on one surface of the water vapor permeability evaluation cell to enter the corrosive metal layer. This is a step of measuring a change in optical properties of the layer, and a step of measuring a change in optical properties of a corroded portion of the corrosive metal layer by using an illumination device and a measurement device of a water vapor permeability evaluation device described later.

  As the means for measuring, a photomultiplier tube or a spectroscope can be used.

  When a spectroscope is used, light is incident from one surface side of the water vapor permeability evaluation cell, and the change in the optical property of the corrosive metal layer is measured while moving in a spot manner by reflected light or transmitted light. Is preferred.

  When an image of the specified range of the corroded metal layer is taken as an image, light is incident from one surface side of the water vapor permeability evaluation cell, and reflected light or transmitted light is converted into an area type or a line sensor type CCD. Or a CMOS camera, and among them, it is preferable to use an area-type CCD or CMOS camera.

  Step (2) is a step of measuring a change in optical characteristics of the corrosive metal layer by irradiating light from one surface side of the water vapor permeability evaluation cell before and after exposure to water vapor. There is a case where the reflected light of the light incident on the light source is measured and a case where the transmitted light is measured. If the gas barrier film is transparent, it is preferably a step of measuring transmitted light.

  This is because, in the present invention, the change in the optical characteristics of the corroded portion is measured, the amount of change in the optical characteristics of the corroded portion is determined, and the volume of the corroded metal is calculated from the area and thickness of the corroded portion by data processing. It is a preferred embodiment to measure transmitted light which is less affected by noise and the like due to reflected light from the device.

  The measurement is preferably performed every predetermined time after exposure to water vapor. In this way, it is possible to make data on how corrosion progresses over time.

  “Exposing to water vapor” means that the evaluation cell is stored in, for example, a thermo-hygrostat to be brought into contact with water vapor. The temperature and humidity conditions of the constant temperature and humidity chamber are appropriately selected. For example, the temperature is preferably in the range of room temperature to 90 ° C., and the relative humidity is preferably in the range of 40 to 90% RH. preferable. The storage time in the constant temperature and humidity chamber is not particularly limited, but is preferably selected from about 10 to 2,000 hours, and the evaluation cells are taken out once at appropriate intervals during the storage time and evaluated. Is also good.

(3) Step of Measuring Optical Property Change by Data Processing In the step (3), the specified range of the corrosive metal layer is divided into a fixed unit area and a fixed number of divisions equal to or more than 10 equal parts. Then, this is a step of measuring the amount of change in the optical characteristics of each part corresponding to each other.

And certain unit area, equally divided surface areas of corrosion metal layer divided into the 10 least equal parts is Ru der range of 0.01~3mm ^2. More preferably, it is in the range of 0.1 to ² mm ² . This is because if the division area is 3 mm ² or less, the data is not discrete and the variation can be sufficiently expressed. On the other hand, if the division area is 0.01 mm ² or more, the corrosive metal layer disappears due to corrosion. This is because the influence of the portion becomes small and there is no problem in calculating the variation.
As described above, the optical characteristics are the light reflectance, transmittance, or luminance value of the corrosive metal layer, and the amount of change in these characteristics within a predetermined time is obtained from data analysis. Data analysis is controlled by a CPU (Central Processing Unit), and is performed in a dedicated data processing unit 14 described later.

Further, Step (3) Te odor, further, within the range specified in the corrosive metal layer, aliquoted by changing the unit area of two or more, a plurality of the division number of each portion corresponding to the cross There is a step (6) of measuring the amount of change in the optical characteristics, calculating the average value and the standard deviation in steps (4) and (5) described later, and confirming the accuracy of the calculated value .

(4) Water Vapor Permeability Calculation Step In the step (4), a data processing unit (water vapor permeability calculation unit 14b), which will be described later, calculates the thickness of the corroded portion from the amount of change in the optical characteristics obtained by the data processing. , Calculating the volume of the corroded portion by multiplying the area of the corroded portion, and calculating the water vapor permeability based on the data.

For example, in step (1), the surface area of the corrosive metal layer is formed to be 1 cm ² , and the image data taken in step (2) is divided into 100 equal parts so that the area becomes 1 mm ² each, Calculate the thickness of the corrosive metal layer converted from the change in the optical characteristics (light reflectance, light transmittance or brightness value) of each part corresponding to each other before and after exposure, and corrode by multiplying the area. The volume of the metal layer is calculated.

  The thickness of the corroded metal layer is determined based on the amount of change because the amount of change in optical characteristics (light reflectance, light transmittance or luminance value) is proportional to the amount of water vapor chemically bonded to the corrosive metal. It is possible.

  Specifically, the optical characteristics of the corrosive metal layer formed beforehand are measured before being exposed to water vapor, and then, while being corroded by being exposed to water vapor in a model under the temperature and humidity conditions in the evaluation of the present invention, the optical characteristics are measured. Trace the change of the characteristic. At the same time, while monitoring the thickness of the corroded metal layer with an optical microscope etc., analyze the relationship between the measured amount of change in optical characteristics and the corresponding thickness of the corroded metal layer, and create a calibration curve. deep.

  In this method, the thickness of the corroded metal layer corresponding to the amount of change in the optical properties can follow Lambert-Beer's law, and can be approximated by a linear function within a certain range. .

  Further, from the obtained thickness of the corroded metal layer, it can be obtained as the following corrosion rate (%), and when the volume of the corroded metal layer is obtained, the corrosion rate can be used.

Corrosion rate (%) = (thickness of corroded metal layer / thickness of preformed corrosive metal layer) × 100
In the model experiment, although it is not limited, since it is necessary to accurately measure the amount of change in the optical characteristics, it is not necessary to consider the influence (noise) of the measurement environment due to light reflection or the like. It is preferable to use a method of capturing transmitted light to obtain an image.

  Therefore, since the thickness of the corroded metal layer can be known from the calibration curve obtained by the above model experiment, it is calculated from the corroded area and the thickness of the corroded metal in the water vapor permeability evaluation cell subjected to the constant temperature and constant humidity treatment. By observing the total volume of the corroded metal object with time, the amount of water reacted with the corrosive metal is calculated, so that the water vapor permeability of the evaluation sample can be quantitatively evaluated.

  Corrosive metals change into metal hydroxides by reacting with moisture. As shown in the following formula (1), 1 mol of a metal having a valence a reacts with amol of water to generate 1 mol of a metal hydroxide.

(Equation _{1) M + aH 2 O →} M (OH) a + (a / 2) H 2
Therefore, the amount of water vapor permeated depends on the temperature and humidity treatment time, the surface area of the corrosive metal layer of the water vapor permeability evaluation cell and the corroded metal surface area after the treatment, the thickness of the corroded metal layer, the corroded portion of the corrosive metal. (Equation 3) from the thickness correction coefficient and the density of the metal hydroxide after corrosion.

Molar amount of metal hydroxide after constant temperature and humidity treatment (X):
(Equation 2) X = (δ × t × d _(MOH) ) / M _(MOH)
Water vapor permeability (g / m ² / day):
(Equation 3) Water vapor transmission rate (g / m ² / day) = X × 18 × m × (10 ⁴ / A) × (24 / T)
Constant temperature and humidity treatment time: T (hour)
Surface area of corrosive metal layer: A (cm ² )
Thickness of corroded corrosive metal layer: t (cm)
Corroded metal surface area: δ (cm ² )
Metal hydroxide molecular weight after corrosion: M _(MOH)
Density of metal hydroxide after corrosion: d _(MOH) (g / cm ³ )
Valence of corrosive metal: m
Here, the thickness of the corroded corrosive metal layer is obtained by calculating the corrosion rate from the amount of change in the optical characteristics and converting it to a thickness.

(5) Step of Calculating Average Value and Standard Deviation of Water Vapor Permeability In the step (5), each divided into a certain number of divisions equal to or more than 10 in a certain unit area obtained in the step (4). This is a step of calculating an average value and a standard deviation in a data processing unit (water vapor permeability distribution calculating unit 14c) described later based on the data of the water vapor permeability of the portion. Both the average value and the standard deviation can be determined by an ordinary method, and the average value is an arithmetic average value. Further, since it is preferable to use a histogram to represent the variation, it is also preferable to create a histogram in the data processing unit (water vapor permeability distribution calculation unit 14c).

(How to find standard deviation)
The standard deviation is calculated from the value obtained by converting the value of the water vapor permeability into a logarithm by the following method.

次に、上で求めた母平均 ｍを使って下記数式２で分散を求める。N pieces of data x1, x2,. . . , XN as a population, and an arithmetic mean (population average) m of the population is obtained by the following equation 1:

Next, the variance is obtained by the following equation 2 using the population mean m obtained above.

この分散（σ^２）の正の平方根σを、標準偏差とする。

The positive square root σ of this variance (σ ² ) is defined as a standard deviation.

  For example, the water vapor permeability of the entire gas barrier film can be determined by calculating the average value of the data of each of the divided portions. It is preferable to employ the following method.

Using a plurality of the water vapor permeability evaluation cells, the image data obtained from them is combined into one image so that the total surface area of the corrosive metal layer is 10 cm ² or more, and the water vapor permeability of each cell is synthesized. It is preferable to calculate the arithmetic average value of the values and determine the water vapor permeability of the entire film, and further calculate the standard deviation of the water vapor permeability at a location divided by a fixed unit area in each cell to calculate the variation of the entire film. Such a processing flow can also be performed by the data processing unit (water vapor permeability distribution calculation unit 14c). Alternatively, data of each part divided by each water vapor permeability evaluation cell may be calculated, and the data may be combined to calculate a standard deviation.

  By adding a plurality of water vapor permeability evaluation cells, not only the variation of each evaluation cell but also the characteristics of the whole film can be expressed.

[2] Water Vapor Permeability Evaluation Apparatus and System Hereinafter, an example of a preferable water vapor permeability evaluation apparatus and system for the present invention will be described.

[2-1] Configuration of Water Vapor Permeability Evaluation Apparatus and System The water vapor permeability evaluation apparatus of the present invention is an apparatus capable of sequentially performing the steps (1) to (5), and includes a water vapor permeability evaluation cell. Means for irradiating the illumination light from one direction to the oblique direction or the normal direction, and means for measuring either reflected light from the water vapor permeability evaluation cell or transmitted light emitted from the opposite surface. , The designated area of the corrosive metal layer is divided into a fixed unit area having a surface area within a range of 0.01 to ³ mm ² into a predetermined number of divisions equal to or more than 10 equal parts, and Means to calculate the area and thickness by analyzing the data of the corroded part from the amount of change in the optical characteristics of the part, and calculate the water vapor permeability and the variation of the water vapor permeability from the obtained area and thickness of the corroded part Means for performing Preferred.

  Hereinafter, an apparatus and a system for evaluating water vapor transmission rate will be described by taking, as an example, an imaging apparatus using a CCD camera, which is a preferred measuring means in the present invention, and image processing using an image captured by the imaging apparatus.

  FIG. 2A shows an example of the configuration of the water vapor permeability evaluation device and the water vapor permeability evaluation system of the present invention, and FIG. 2B shows another example. FIG. 3 shows a functional block diagram of the water vapor permeability evaluation system 100.

  As shown in FIG. 2A, the water vapor permeability evaluation system 100 used in the water vapor permeability evaluation method of the present invention includes a data processing device 10, an imaging adjustment device 20, an imaging device 30, a test piece observation table 40, an external output device 50, and illumination. Preferably, it comprises a device 60.

  The imaging device 30 and the illumination device 60 may irradiate one surface of the evaluation cell from an oblique direction and measure the reflected light. In this case, the arrangement of the imaging device 31 and the illumination device 61 shown in FIG. It is preferred that

[Data processing device]
The data processing device 10 is communicably connected to the imaging adjustment device 20 and the imaging device 30. Hereinafter, each configuration of the data processing device 10 will be described.

  As shown in FIG. 3, the data processing device 10 includes a control unit 11, a recording unit 12, a communication unit 13, a data processing unit 14 (a local water vapor transmission rate calculation unit 14a, a water vapor transmission rate calculation unit 14b, and a water vapor transmission rate distribution calculation unit). 14c), an operation display unit 15, and the like.

The control unit 11 includes a CPU (Central Processing Unit) 11a that integrally controls the operation of the data processing device 10, and a RAM (Random) that functions as a work memory for temporarily storing various data when the CPU 11a executes a program.
Access Memory) 11b, a program memory 11c in which programs read and executed by the CPU 11a and fixed data are stored. The program memory 11c is configured by a ROM or the like.

  The recording unit 12 stores, in addition to the image data captured by the imaging device 30, data of various thresholds used in the data processing unit, irradiation condition data of the lighting device 60, the value of the water vapor transmission rate actually measured in the evaluation, Data related to the method for evaluating water vapor permeability of the present invention, such as thickness conversion data of a corrosive metal layer in a corroded portion, is stored and recorded.

  The communication unit 13 includes a communication interface such as a network I / F, and transmits the measurement condition input from the operation display unit 15 to the imaging adjustment device 20 via a network such as an intranet. Further, the communication unit 13 receives image data sent from the imaging device 30.

  The data processing unit 14 analyzes the amount of change in the optical characteristics of the whole and the finely divided portion from the image data of the corrosive metal layer received by the communication unit 13 and captured by the imaging device 30.

  The data processing unit 14 includes a local water vapor transmission rate calculation unit 14a, a water vapor transmission rate calculation unit 14b, and a water vapor transmission rate distribution calculation unit 14c used in step (3), step (4), and step (5).

The local water vapor transmission rate calculating unit 14a stores the surface area of the corrosive metal layer in the specified range of the images obtained by the photographing before and after the exposure to the water vapor in steps (3) and (4) of 0.01 to 0.01 , respectively. It is divided into a certain number of divisions equal to or more than 10 in a certain unit area within a range of 3 mm ^{2, and} the amount of change in the optical characteristics of each part corresponding to each other is measured, and the optical characteristics obtained by the measurement are measured. Is a means for calculating the volume of the corroded portion from the amount of change and calculating the water vapor permeability based on the volume.

  The water vapor permeability calculating unit 14b and the water vapor permeability distribution calculating unit 14c are means for calculating an average value and a standard deviation based on the water vapor permeability data of each part obtained in the step (5). .

  The operation display unit 15 may include, for example, an LCD (Liquid Crystal Display), a touch panel provided to cover the LCD, various switches and buttons, ten keys, operation keys, and the like (not shown). The operation display unit 15 receives an instruction from a user and outputs an operation signal to the control unit 11. Further, the operation display unit 15 displays, on the LCD, an operation screen for displaying various setting screens for inputting various operation instructions and setting information, various processing results, and the like, in accordance with a display signal output from the control unit 11.

[Imaging adjustment device]
The imaging adjustment device 20 adjusts the imaging device 30 based on the measurement conditions received from the data processing device 10.
More specifically, the imaging adjustment device 20 determines the imaging device based on the measurement conditions received from the data processing device 10, for example, the position (height) from the water vapor permeability evaluation cell, the shooting interval, the moving speed, the imaging magnification, and the like. 30 can be adjusted.

[Imaging device]
The illumination device 60 is arranged in the normal direction of the water vapor permeability evaluation cell F, the illumination light is applied to the water vapor permeability evaluation cell F, and the transmitted light is photographed by the imaging device 30. The positions of the lighting device 60, the water vapor permeability evaluation cell F, and the image pickup device 30 are set in order to image the change in transmitted light due to corrosion of the water vapor permeability evaluation cell F with high sensitivity.

  When the evaluation is performed based on the reflected light from the water vapor transmission rate evaluation cell F, as shown in FIG. The light is applied to the cell F, and the reflected light is photographed by the imaging device 31. The positions of the lighting device 61, the water vapor permeability evaluation cell F, and the imaging device 31 are set in order to image the change in transmitted light due to corrosion of the water vapor permeability evaluation cell F with high sensitivity. That is, the incident angle of light from the lighting device 61 to the water vapor transmission rate evaluation cell F and the reflection angle from the water vapor transmission rate evaluation cell F to the imaging device 31 are made equal.

  As the imaging device 30, an area type or line sensor type CCD camera can be used. When the measurement target range of the water vapor permeability evaluation cell F can be covered by photographing within several times, the area type is used, and when it is necessary to photograph a wider range, the line sensor type is used. Preferred in terms of surface.

  An area-type camera is preferably used. In the case of an area-type camera, it is desirable to determine the lens and photographing conditions so that one pixel is 50 μm or less in order to obtain a preferable variation.

[Lighting device]
The illumination device 60 needs to have a sufficient area for capturing the reflected light or the transmitted light with the imaging device 30, and it is preferable that the luminance is as uniform as possible.

  Although the light source of the lighting device 60 is not particularly limited, a fiber-type light source using a deuterium lamp, a halogen lamp, or an LED (Light Emitting Diode) lamp as a light source, or a fluorescent lamp, an LED, or an OLED (Organic Light Emitting). (Diode) can be used. Preferably, it is a surface light source.

[Specimen observation table]
It is preferable that the test piece observation table 40 includes, for example, a test piece fixing table 41, a two-axis electric stage 42, and an apparatus frame 43. When capturing the transmitted light, the test piece fixing table 41 needs to have a hollow or transparent portion so as not to block the transmitted light.

  Specifically, the test piece observation table 40 fixes the water vapor permeability evaluation cell F by the test piece fixing table 41. Even when the water vapor permeability evaluation cell F serving as a sample is wound in a roll, for example, the short axis direction is fixed by the test piece fixing table 41, and the biaxial electric stage is moved at a predetermined speed. By moving and moving the water vapor permeability evaluation cell F in the long axis direction, the imaging device 30 can measure a wider range than the test piece observation table 40.

  Note that the test piece observation table 40 may be communicably connected to the data processing device 10. The speed at which the water vapor permeability evaluation cell is moved may be set by the data processing device 10 by connecting the data processing device 10 and the test piece observation table 40 so that they can communicate with each other.

[External output device]
The data processing device 10 may include an external output device 50 communicably connected to the data processing device 10. The external output device 50 may be a general PC (Personal Computer), an image forming apparatus, or the like. Further, the external output device 50 may function as an operation display unit instead of the operation display unit 15 of the data processing device 10.

[2-2] Flowchart of Water Vapor Permeability Calculation Method Next, a measurement example of the water vapor permeability calculation method will be described with reference to the flowchart shown in FIG. In the following description, the evaluation sample shows an example using a gas barrier film.

  The input data includes data such as an imaging condition, a measurement mode (transmitted light system or reflected light system), and image division parameter settings such as an image division area and the number of divisions (S1). It is also preferable that several types of image division parameters are set at the same time so that the evaluation results can be compared as needed.

  Image data of a corroded portion on the gas barrier film surface is obtained from the input data (S2). The local water vapor permeability calculating unit 14a performs image processing for obtaining the amount of change in the optical characteristics of each of the divided portions of the corroded metal layer captured (S3).

  As a result of the image processing, an optical change amount of the corrosive metal layer according to the input measurement mode is obtained as an output (S4). The thickness of the corroded portion is determined based on the calibration curve of the optical change amount and the thickness of the corroded metal layer, which is created in advance from the change amount, and the corrosion rate of each portion is calculated (S5).

  Next, in the case of the measurement of the reflection system, the water vapor transmission rate is calculated by the following formula (i) in the water vapor transmission rate calculating section 14b (S6).

In the formula, WVTR is an abbreviation for Water Vapor Transmission Rate. A is a constant calculated in advance, and A = (3.3445 × 10 ⁻²⁾ .

(I) Reflected WVTR (g / m ² / day) = A × corrosion metal layer thickness due to reflected light: 0 hr) (nm) × corrosion rate (%) / measurement time (hr)
In the case of the transmission system, the thickness of the corroded metal layer due to the transmitted light is calculated, and from the obtained thickness of the corroded metal layer due to the transmitted light, the transmission WVTR is similarly calculated from the following formula (ii) (S8).

(Ii) Transmitted WVTR (g / m ² / day) = A × Thickness of corroded metal layer by transmitted light: 0 hr
) (Nm) × corrosion rate (%) / current measurement time (hr)
Using the water vapor permeability data for each pixel (equally divided portion) obtained above, the water vapor permeability distribution calculator 14c calculates the average value and the standard deviation of the reflected WVTR or the transmitted WVTR (S7). . At this time, a histogram of the water vapor transmission rate for each pixel can be created.

  The data of the water vapor permeability described above is reflected in the database of the recording unit 12.

Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited thereto.
<Equipment and evaluation sample used in the water vapor permeability evaluation method>
1. Evaporator: Vacuum evaporator JEE-400 manufactured by JEOL Ltd.
2. Constant temperature and humidity oven: Yamato Humic Chamber IG47M
3. Gas barrier film The gas barrier film used for evaluation was produced by the following method.

(Formation of gas barrier layer)
On a polyethylene terephthalate (PET) substrate (Cosmoshine A4300, manufactured by Toyobo Co., Ltd.) having a thickness of 100 μm and easily bonded to both surfaces, perhydropolysilazane and an amine catalyst solution were spin-coated using a spin coater. After drying, the surface was irradiated with vacuum ultraviolet light (excimer modification treatment) to modify the polysilazane-containing layer to form a gas barrier layer. At that time, the gas barrier film used for evaluation was produced by changing the modification conditions.

4. Metal that corrodes by reacting with moisture: calcium (granular)
<Example 1>
Calcium (Ca: corrosive metal) is vapor-deposited on a 25 mm square glass with an area of 10 mm square using a vacuum evaporator JEE-400 manufactured by JEOL Ltd. with an adhesive (three bond). 1655) was sealed with a gas barrier film (gas barrier film A, gas barrier film B and gas barrier film C) to which a gas barrier film for evaluating the water vapor permeability of the gas barrier film was produced. The gas barrier film to which the adhesive was bonded was left in a glove box (GB) for 24 hours to remove moisture of the adhesive and adsorbed water on the surface of the gas barrier film.

  As shown in FIG. 2A, light was incident from the normal direction on the glass surface side, and transmitted light was photographed from the opposite surface side of the produced evaluation cell using an area CCD camera. Thereafter, the evaluation cell was left in a constant temperature / humidity chamber (Yamato Humidic Chamber IG47M) of 85 ° C. and 85% RH for 98 hours, and similarly photographed with a CCD camera.

From the obtained image, 8 mm square at the center was cut out, and the brightness value of the whole cut out image was obtained, and the calcium film thickness was calculated from the brightness value prepared in advance and a calibration curve of the calcium film thickness. From the obtained calcium film thickness, the change in film thickness before and after being put in a thermo-hygrostat was calculated, and the water vapor permeability (WVTR) of the entire cell was calculated from the data. 7 × 10 ⁻³ g / m ² / day, gas barrier film B was 8 × 10 ⁻³ g / m ² / day, and gas barrier film C was 5 × 10 ⁻³ g / m ² / day.

Further, the cut-out image of 8 mm square was divided into 64 so as to have a size of 1 mm ² , the luminance value of each divided portion was obtained, and the calcium film thickness and water vapor permeability (WVTR) were calculated. When the standard deviation (σ) was calculated from the value obtained by converting the obtained 64 water vapor permeability (WVTR) values into logarithms, the gas barrier film A was 0.21, the gas barrier film B was 0.17, and the gas was 0.17. The barrier film C was 0.04.

  The above data is shown in FIG. According to the data shown in FIG. 5, the gas barrier film A has slightly better water vapor permeability (WVTR) than the gas barrier film B, but the distribution (standard deviation) of the in-plane water vapor permeability is inferior. On the other hand, the gas barrier film C is superior to the samples A and B in that the water vapor permeability (WVTR) of the whole film is excellent and the distribution of the water vapor permeability in the plane (standard deviation σ) is significantly small. Among the three, it can be evaluated as a gas barrier film having the most desirable gas barrier properties.

<Example 2>
Calcium (Ca: corrosive metal) is vapor-deposited on a glass of 25 mm square with an area of 12 mm square using a vacuum evaporation system JEE-400 manufactured by JEOL Ltd. with an adhesive (three bond). 1655) was sealed with a gas barrier film (gas barrier film D and gas barrier film E) to which a gas barrier film for evaluating the water vapor permeability of the gas barrier film was produced. The gas barrier film to which the adhesive was bonded was left in a glove box (GB) for 24 hours to remove moisture of the adhesive and adsorbed water on the surface of the gas barrier film.

  As shown in FIG. 2A, light was incident from the normal direction on the glass surface side, and transmitted light was photographed from the opposite surface side of the produced evaluation cell using an area CCD camera. After that, the evaluation cell was left for 100 hours in a constant temperature and humidity chamber (Yamato Humidic Chamber IG47M) of 85 ° C. and 85% RH, and similarly photographed with a CCD camera.

10 mm square at the center was cut out from the obtained image, and the luminance value of the whole cut out image was obtained. The calcium film thickness was calculated from the luminance value prepared in advance and the calibration curve of the calcium film thickness. From the obtained calcium film thickness, the change in film thickness before and after being put in a thermo-hygrostat was calculated, and the water vapor permeability (WVTR) of the entire cell was calculated from the data. Both were 2 × 10 ⁻³ g / m ² / day.

In addition, the cut-out 10 mm square image was divided into 100 parts so as to have a size of 1 mm ² , the luminance value of each part was obtained, and the calcium film thickness and the water vapor permeability (WVTR) were calculated. When the standard deviation (σ) was calculated from the logarithmically converted values of the obtained 100 water vapor permeability (WVTR) values, the gas barrier film D was 0.14 and the gas barrier film E was 0.45. Was.

  From the above, the gas barrier films D and E have the same gas barrier performance over the entire surface, but the gas barrier film D has a small in-plane variation and the quality of the gas barrier film is high. On the other hand, it was found that the gas barrier film E had a large in-plane variation of the gas barrier layer, the quality of the gas barrier film was low, and defects were scattered.

  Thus, by quantifying the in-plane performance distribution (variation) that could not be expressed conventionally, the quality of the gas barrier film could be expressed quantitatively.

<Example 3>
Using a gas barrier film A with a film formation effective width of 1000 mm, cut out 25 mm squares at 100 mm intervals from the center of the width, and bond with 12 mm square calcium vapor-deposited glass via an adhesive (1655 made by Three Bond). Was carried out to produce a cell for evaluating the water vapor permeability of the gas barrier film. In addition, in order to remove the moisture of the adhesive and the adsorbed water on the surface of the gas barrier film, the gas barrier film and the adhesive were bonded in advance. It was left in a glove box (GB) day and night.

From the image obtained by shooting in the same manner as in Example 1, a central 10 mm square was cut out, and the brightness value of the whole cut out image was obtained. From the brightness value prepared in advance and the calibration curve of the calcium film thickness, the calcium film was obtained. The thickness was calculated. From the obtained calcium film thickness, the amount of change in the film thickness before and after the calcium film was placed in a thermo-hygrostat was calculated, and further, the water vapor permeability (WVTR) of the whole cell was calculated. In addition, the cut-out image of 10 mm square was divided into 100 parts so as to have a size of 1 mm ² , the luminance value of each part was obtained, and the calcium film thickness and water vapor permeability (WVTR) were calculated. Further, a standard deviation (σ) was determined from a value obtained by converting the obtained value of the water vapor permeability into a logarithm.

  The results are shown in Table 1.

  The water vapor transmission rate (WVTR) of the whole cell tended to slightly increase toward the width end, but the variation (standard deviation) of each evaluation cell did not change. Note that the fluctuation of the water vapor permeability (WVTR) of the entire evaluation cell was consistent with the tendency of the wide film thickness distribution, and it was found that the fluctuation was caused by the film forming apparatus.

<Example 4>
In the same manner as in Example 1, the water vapor permeability was evaluated under the following conditions.

Gas barrier film: Gas barrier film C,
Film / glass size: 30 × 190mm,
Calcium deposition area: 10 × 170 mm,
Image size: 9 × 50 mm × 3 places, combined into one image Average value of water vapor transmission rate (WVTR) of each cell: Water vapor transmission rate (WVTR) of entire film
The variation (standard deviation) of the entire film was calculated by combining the values of the water vapor transmission rate (WVTR) of the portions divided into 1 mm ² in each cell.

  By adding a plurality of evaluation cells, not only the variation of each evaluation cell but also the characteristics of the entire film could be expressed.

<Example 5>
In the same manner as in Example 1, the water vapor permeability was evaluated under the following conditions.

Gas barrier film: Gas barrier film C,
Film / glass size: 68mm □,
Calcium deposition area: 50mm □,
Image cropping: 48mm □
Image division number: 2304 divisions (1 mm ² each) and 3291 divisions (0.7 mm ² each) Variations (standard deviations) are calculated and compared with each of the plural division numbers to further increase measurement accuracy. I was able to.

  Since the water vapor permeability evaluation method of the present invention provides an evaluation method for simultaneously measuring the water vapor permeability and in-plane variation of a gas barrier film or the like, it can be suitably used for designing a gas barrier film.

F Water vapor permeability evaluation cell 1 Moisture permeable substrate 2 Corrosive metal layer 3 Adhesive layer 4 Base film 5 Gas barrier layer 6 Evaluation sample 100 Water vapor permeability evaluation system 10 Data processing device 11 Control unit 12 Recording unit 13 Communication unit 14 Data Processing Unit 14a Local Water Vapor Permeability Calculator 14b Water Vapor Permeability Calculator 14c Water Vapor Permeability Distribution Calculator 15 Operation Display 20 Imaging Adjuster 30, 31 Imaging Apparatus 40 Test Piece Observation Table 41 Test Piece Fixing Table 42 Biaxial Electric stage 43 Device frames 60, 61 Lighting device

Claims (6)

A method for evaluating water vapor transmission rate using a corrosive metal that corrodes by reacting with moisture, comprising at least the following steps (1) to ( 7 ).
(1) A step of producing a water vapor permeability evaluation cell in which a moisture impermeable substrate, a corrosive metal layer which is corroded by reacting with water, and an evaluation sample are provided in this order.
(2) a step of measuring a change in optical characteristics of the corrosive metal layer by irradiating light from one surface side of the water vapor permeability evaluation cell before and after the exposure to water vapor.
(3) The designated area of the corrosive metal layer is divided into a fixed unit area having a surface area within a range of 0.01 to ³ mm ² into a predetermined number of divisions equal to or more than 10 equal parts, and corresponding to each other. Measuring the amount of change in the optical characteristics of each part.
(4) calculating the volume of the corroded portion from the amount of change in the optical characteristics obtained in the measurement, and calculating the water vapor permeability based on the volume.
(5) calculating an average value and a standard deviation based on the water vapor permeability of each portion obtained in the step (4).
(6) In the step (3), the specified area of the corrosive metal layer is further divided equally by changing the unit area by at least two kinds, and the mutually corresponding portions are divided in a plurality of division numbers. Measuring the amount of change in the optical characteristics of the above, calculating the average value and the standard deviation in steps (4) and (5), and confirming the accuracy of the calculated value.   The step (2) is a step in which light is incident on one surface side of the water vapor permeability evaluation cell, and transmitted light emitted from the opposite surface is photographed to obtain an image. 2. The method for evaluating water vapor permeability according to 1. The water vapor permeability evaluation method according to claim 1, wherein a surface area of the corrosive metal layer is 1 cm ² or more. The water vapor according to any one of claims 1 to 3, wherein a plurality of the water vapor permeability evaluation cells are used so that the total surface area of the corrosive metal layer is 10 cm ² or more. Transmittance evaluation method. The said step (1) produces the water vapor permeability evaluation cell by bonding the said evaluation sample and the said water impermeable board | substrate with a photocurable adhesive or a thermosetting adhesive. The method for evaluating water vapor permeability according to any one of claims 1 to 4 . It is a water vapor permeability evaluation device which performs the water vapor permeability evaluation method according to any one of claims 1 to 5 ,
Means for irradiating the illumination light from one side of the water vapor permeability evaluation cell from an oblique direction or a normal direction,
Means for measuring either reflected light from the water vapor permeability evaluation cell or transmitted light emitted from the opposite surface,
The specified range of the corrosive metal layer is divided into a fixed unit area having a surface area within a range of 0.01 to ³ mm ² into a predetermined number of divisions equal to or more than 10 and divided into corresponding portions. Means for calculating the area and thickness of the corroded portion by analyzing the data from the amount of change in the optical characteristics of the above, and calculating the water vapor permeability and the variation of the water vapor permeability from the obtained area and thickness of the corroded portion. Means,
A water vapor permeability evaluation device comprising:

Images