KR102219619B1 - Standard gas barrier film - Google Patents

Abstract

The present invention provides a standard gas barrier film having a ^{water vapor permeability of 10 -6} to 10 ^-3 g/m ^{2 /day.} The standard gas barrier film 10 is used for calibration of a water vapor permeability measuring device. The standard gas barrier film 10 has a substrate 12 having an opening 12a and a barrier layer 14 provided on the substrate 12 so as to cover the opening 12a. The barrier layer 14 contains nanoparticles of Li-type montmorillonite and polyimide. The ratio of the maximum diameter of the opening 12a to the thickness of the barrier layer 14 is 50 to 2000. This standard gas barrier film 10 has a water vapor permeability of 10 ^-6 to 10 ^-3 g/m ² /day at 40°C and 90% relative humidity. The base material 12 is a metal plate having an arithmetic mean roughness Ra of 2 nm or less on the side opposite to the side on which the barrier layer 14 is provided.

Description

Standard gas barrier film

The present invention relates to a standard gas barrier film used for calibration or evaluation of a gas permeability measuring device.

Gas barrier films are used for packaging and sealing of foods and electronic parts, depending on the permeability of water vapor and oxygen. For this reason, it is important to accurately measure the water vapor or oxygen permeability of the gas barrier film. Measurement of water vapor permeability of a gas barrier film can be classified into an isostatic pressure method and a differential pressure method.The cup method, electrode method, calcium method, Mocon method, gas chromatography method, API-MS method, etc. are used for the isostatic pressure method, and the pressure method is used for the differential pressure method. The welding method and the gas permeability measurement described in Patent Literature 1 are provided. Most of the gas permeability measuring devices require a standard gas barrier film for calibration of device constants, comparison of results between different measuring devices, and evaluation of the integrity of the measuring devices.

On the other hand, in an organic EL device or an organic solar cell ^{, a gas barrier film having a water vapor transmittance on the order of 10 -6} g/m ² /day is required as a sealing material for preventing deterioration. However, in the commercially available standard gas barrier film, in the standard gas barrier film traceable by the National Institute of Standards and Technology (NIST), the water vapor transmission rate is the minimum of ^{3.2 × 10 -2} g/m ^{2 /day,} In the developed standard gas barrier film, the water vapor permeability of 8 × 10 ^-3 g/m ² /day is the minimum (Non-Patent Document 1). Various organizations are ^{developing and evaluating the standard gas barrier film on the order of 10 -4} g/m ² /day, but there was a variation of about one digit in the measurement result, and a highly reliable result was not obtained (Non-Patent Document 2 And non-patent literature 3). Therefore, these standard gas barrier films cannot be used for calibration or evaluation of an apparatus for measuring the gas permeability of a gas barrier film on the order of ^{10 -6} g/m ^{2 /day.}

The standard gas barrier film traceable by the National Institute of Standards and Technology (NIST) has a structure in which a plastic film is attached to a metal plate with a hole, and the opening area of the opening of the hole is proportional to the water vapor transmission amount. Are seeking. In this structure, in order to manufacture a standard gas barrier film having a smaller water vapor permeability, there are two methods: a method of reducing the diameter of a hole and a method of attaching a plastic film having a small water vapor permeability.

However, when the diameter of the hole is reduced by the former method, the processing accuracy of punching and the measurement accuracy of the shape measurement of the hole are deteriorated, so the variation in the water vapor transmission rate of the standard gas barrier film increases. In addition, since the ratio of the film thickness of the plastic film to the hole diameter becomes large, there arises a problem in that the concentration distribution of water vapor occurs in the surface of the plastic film, and the opening area of the opening of the hole is not proportional to the water vapor transmission amount. For this reason, a standard gas barrier film with high reliability cannot be produced.

In the latter method, a standard gas barrier film in which a plastic film obtained by multilayer coating an inorganic gas barrier layer on an organic film is attached to a substrate is considered. However, even with this method, a highly reliable standard gas barrier film cannot be produced. Since gas barrier properties are expressed by the maze effect, the fluctuation of gas permeability within the surface of the gas barrier film is large, and the water vapor permeability of the standard gas barrier film depends on which location of the gas barrier film is used to produce the standard gas barrier film. This is because is greatly different. In addition, it is because the organic film swells to cause damage to the inorganic gas barrier layer, and thus measurement reproducibility cannot be obtained.

In addition, when a plastic film coated with a multi-layered inorganic gas barrier layer is used as a standard gas barrier film, there is a problem that the behavior of water vapor passing through the multilayer film is complicated, and it is difficult to determine the point at which the water vapor permeability is saturated. In addition, in the case of measuring a high barrier, it is desired to heat and degas the standard gas barrier film to reduce outgassing from the standard gas barrier film itself. However, the standard gas barrier film produced in this way is 100°C or higher. Can't stand baking Further, when the inorganic gas barrier layer is adhered to the plastic film using an adhesive, the water vapor permeability in the adhesive becomes a problem.

International Publication No. 2015/041115 Japanese Patent Publication No. 2007-277078

Kazukiyo Nagai et al., Latest Barrier Technology-Barrier Film, Barrier Container, Current Situation and Development of Sealing Materials and Sealing Materials-, 2011, CMC Publishing Co., Ltd. Giovanni Nisato et al., Organic Electronics, 2014, 15, p.3746-3755 P. J. Brewer et al., Review of scientific instruments, 2012, 83, 075118

The present invention has been made in view of these circumstances, and an object of the present invention is to provide a standard gas barrier film that can be used in an apparatus for measuring the gas permeability of a gas barrier film on the order of ^{10 -6} g/m ^{2 /day.}

The standard gas barrier film of the present invention is used for calibration of a water vapor permeability measuring device, and has a substrate having an opening and a barrier layer provided on the substrate to cover the opening, and the barrier layer is Li-type montmorillonite nanoparticles and polyee It contains mid, and the ratio of the maximum diameter of the opening to the thickness of the barrier layer is 50 to 2000. In the standard gas barrier film of the present invention, it is preferable that the substrate and the barrier layer are directly bonded to each other. The standard gas barrier film of the present invention preferably has a water vapor permeability of 10 ^-6 to 10 ^-3 g/m ² /day at 40°C and 90% relative humidity.

In the standard gas barrier film of the present invention, the base material may be a metal plate having an arithmetic mean roughness Ra of 2 nm or less on the side opposite to the side on which the barrier layer is provided. In the standard gas barrier film of the present invention, the number of openings is 1 to 10, and the maximum diameters of all openings may be 1 to 20 mm. In the standard gas barrier film of the present invention, it is preferable that the mass of polyimide is 20 to 40% with respect to the sum of the masses of Li-type montmorillonite and polyimide.

The manufacturing method of the standard gas barrier film of the present invention is a method of manufacturing a standard gas barrier film, which has a substrate having an opening and a barrier layer provided on the substrate so as to cover the opening, and is used for calibration of a water vapor transmission rate measuring device, A step of obtaining a laminate including a laminated portion of a film body containing Li-type montmorillonite nanoparticles and polyamic acid, and a plastic film, and heating the laminate at a first temperature while pressing the laminate against the substrate so that the film body covers the opening, After that, it is equal to or higher than the first temperature, and has a step of heating at a second temperature at which polyamic acid is imidized. In the method for producing a standard gas barrier film of the present invention, it is preferable that the first temperature is 60 to 150°C and the second temperature is 150 to 350°C.

According to the present invention, a standard gas barrier film having a ^{water vapor permeability of 10 -6} to 10 ^-3 g/m ^{2 /day is obtained.}

1 is a top view of a standard gas barrier film according to an embodiment of the present invention.
2 is a cross-sectional view of a standard gas barrier film according to an embodiment of the present invention.
3 is a cross-sectional view for explaining a method of manufacturing a standard gas barrier film according to an embodiment of the present invention.
4 is a graph showing the results of measuring the ion current of m/z18 of the standard gas barrier films obtained in Examples 1 to 3;
5 is a graph showing the relationship between the m/z18 saturated ion current of the standard gas barrier films obtained in Examples 1 to 3 and the opening area of the opening of the hole.
6 is a graph comparing the saturated ion current of the standard gas barrier films obtained in Examples 1 to 3 with the saturated ion current when water vapor is introduced using a standard conductance element (SCE).

Hereinafter, a standard gas barrier film and a method for producing a standard gas barrier film of the present invention will be described based on embodiments and examples with reference to the drawings. In addition, the drawings schematically show a standard gas barrier film and each member constituting the same, and the dimensions and dimensional ratios of the actual products do not necessarily coincide with the dimensions and dimensional ratios in the drawings. In addition, redundant description is appropriately omitted. In addition, when a numerical range is indicated by describing "to" between two numerical values, these two numerical values are also included in the numerical range.

1 schematically shows an upper surface of a standard gas barrier film 10 according to an embodiment of the present invention. FIG. 2 schematically shows a cross section of the standard gas barrier film 10 when cut along the line A-A in FIG. 1. The standard gas barrier film 10 is used for calibration of a water vapor permeability measuring device. The standard gas barrier film 10 includes a substrate 12 and a barrier layer 14. The substrate 12 is an original plate and is made of metal, for example stainless steel. In the present embodiment, the substrate 12 is an original plate, but the shape of the substrate is not particularly limited, and may be a polygonal plate or an elliptical plate. In addition, although the base material 12 is a metal plate in this embodiment, the material of the base material is not particularly limited as long as the portion in contact with the barrier layer 14 or its periphery does not transmit water vapor. The substrate may be made of ceramic or resin.

The substrate 12 has a columnar opening 12a. In the present embodiment, the opening 12a is cylindrical, but as long as the water vapor transmission rate of the standard gas barrier film 10 can be set to a predetermined value, the shape of the opening 12a is not particularly limited, and a polygonal column, an elliptical column, and a truncated cone Etc. may be used. It is preferable that the maximum diameter of the opening 12a is 1 to 20 mm. This is because the water vapor permeability of the standard gas barrier film 10 can be reduced. In addition, this is because the precision and tolerance of punching machining of the opening 12a that affects the water vapor transmission rate can be sufficiently reduced. Further, the number of openings 12a is preferably 1 to 10. The barrier layer 14 is provided on the base 12 so as to cover the opening 12a. Moreover, the barrier layer 14 contains nanoparticles of Li-type montmorillonite and polyimide.

Montmorillonite is a type of clay called smectite. Montmorillonite is a plate-like crystal with a thickness of 1 nm, and is used as a functional filler added to plastics. When a small amount of montmorillonite is uniformly added to the plastic, gas barrier properties are improved. Montmorillonite, purified from natural minerals, is widely distributed. A film having a high water vapor barrier property can be produced by molding the mixed material containing montmorillonite as a main component to which a binder is added (Patent Document 2). A method for producing a film having high water vapor barrier properties will be described below.

First, Li-type montmorillonite is prepared. Montmorillonite has exchangeable ions, and these exchangeable ions are generally Na or Ca. By ion exchange, it is possible to exchange Na or Ca, which are exchangeable ions in montmorillonite, for Li. Montmorillonite obtained by exchanging exchangeable ions for Li by ion exchange is Li-type montmorillonite. Subsequently, for example, 20 parts by mass of Li-type montmorillonite and, for example, 80 parts by mass of water are mixed to produce a uniform gel (hereinafter sometimes referred to as “Li-type montmorillonite gel”).

Then, a Li-type montmorillonite gel is dispersed in a solvent such as N-methyl-2-pyrrolidone or dimethylacetamide, and the polyamic acid is further mixed with a solution dissolved in this solvent, and formed into a film on a plastic film. . Subsequently, by drying the solvent, a handleable structure is obtained. Then, by peeling the plastic film from the structure and heat-treating the remaining film, the polyamic acid is chemically changed to polyimide, and a film having high water vapor barrier property is obtained. This film is a nanocomposite barrier layer of Li-type montmorillonite and polyimide. It is preferable that the mass of the polyimide relative to the sum of the masses of Li-type montmorillonite and the polyimide is 20 to 40%. This is because the water vapor permeability of the produced barrier layer can be on the order of ^{10 -3} g/m ^{2 /day.}

In addition, from the two viewpoints of eliminating the gap between the substrate 12 and the barrier layer 14 and reducing the outgas from the substrate 12 that affects the measurement of water vapor permeability, the surface of the substrate 12 is It is desirable to be smooth. In particular, when the surface roughness of the surface opposite to the surface on which the barrier layer 14 is provided is large, the amount of water vapor adsorbed to the substrate 12 increases. Since the water vapor adsorbed on the substrate 12 is gradually desorbed during the water vapor permeability measurement, the background of the water vapor measurement becomes large, and as a result, it becomes difficult to measure the water vapor permeability of the high barrier film. Therefore, by using electrolytic polishing, chemical polishing, electrolytic composite polishing, or the like, it is preferable to set the arithmetic mean surface roughness Ra of at least the surface on which the barrier layer is provided on the substrate to be 2 nm or less.

In addition, from the viewpoint of proportioning the water vapor permeability of the standard gas barrier film to the opening area of the opening, the ratio of the maximum diameter of the opening 12a to the thickness of the barrier layer 14, that is, "maximum diameter of the opening 12a/barrier It is preferable that the thickness of the layer 14 is 50 or more. When the water vapor transmittance is measured with the surface on which the barrier layer 14 is provided as the exposure side of water vapor, water vapor that has passed through the barrier layer 14 is released from the opening 12a. For this reason, the water vapor concentration inside the barrier layer 14 at the portion in contact with the opening 12a is lower than the water vapor concentration inside the barrier layer 14 at the portion in contact with the substrate 12. Accordingly, in-plane diffusion of water vapor occurs from the barrier layer 14 at the portion in contact with the substrate 12 to the barrier layer 14 at the portion in contact with the opening 12a. When the influence of the in-plane diffusion of the water vapor is relatively large, the water vapor transmission rate of the standard gas barrier film 10 is not proportional to the opening area of the opening 12a.

The influence of the in-plane diffusion of water vapor becomes negligible as the ratio of the maximum diameter of the opening 12a to the thickness of the barrier layer 14 increases, and becomes sufficiently small at 50 or more. In addition, in this embodiment, by setting the ratio of the maximum diameter of the opening 12a to the thickness of the barrier layer 14 to 50 to 2000, the water vapor transmission rate is 10 ^-6 to 10 ^-3 g/m ² /day. The gas barrier film 10 is prepared. The water vapor permeability of the standard gas barrier film 10 can be measured even by using a water vapor permeability measuring device using either an isostatic pressure method or a differential pressure method. In the case of measuring the water vapor permeability of the standard gas barrier film 10 using an apparatus using the differential pressure method, it is necessary to make the surface on which the barrier layer 14 is provided on the exposed side (high pressure side). This is because if the side opposite to the surface on which the barrier layer 14 is provided is on the exposure side (high pressure side), the barrier layer 14 may be peeled off from the substrate 12.

3 shows the manufacturing process of the standard gas barrier film 10. The standard gas barrier film 10 is manufactured in the following procedure. First, as shown in (a) of FIG. 3, a mixed solution containing Li-type montmorillonite and polyamic acid is applied on a plastic film 16, and dried at 60°C to form the membrane body 13 and the plastic film 16. To obtain a laminate (18) of. More specifically, after mixing Li-type montmorillonite, polyamic acid, and an organic solvent, it is passed through a sieve to remove insoluble lumps to obtain a liquid mixture containing Li-type montmorillonite and polyamic acid.

Then, this mixed solution is applied on the plastic film 16 and heated at a temperature at which the organic solvent is evaporated to obtain the laminate 18. As the plastic film 16, for example, PFA (tetrafluoroethylene/perfluoroalkyl vinyl ether copolymer), PTFE (polytetrafluoroethylene), and PET (polyethylene terephthalate) can be used.

Subsequently, as shown in Fig. 3(b), the laminate 18 is heated at a first temperature while pressing the laminate 18 against the substrate 12 so that the membrane body 13 covers the opening 12a of the substrate 12. , The substrate 12 and the laminate 18 are integrated. More specifically, the substrate 12 and the laminate 18 are integrated by raising the temperature from room temperature to a first temperature, for example, 150° C. while pressing the laminate 18 against the substrate 12. Further, after the membrane body 13 is peeled from the plastic film 16, the membrane body 13 may be heated at a first temperature while pressing the base material 12 to integrate the base material 12 and the membrane body 13 together. At this time, it is preferable to integrate the barrier layer 14 so that the maximum diameter of the opening 12a with respect to the thickness of the barrier layer 14 is 50 to 2000. This is to reduce the water vapor transmission rate of the obtained standard gas barrier film 10 and make the water vapor transmission rate proportional to the opening area of the opening 12a.

And, after peeling the plastic film 16 from the membrane body 13, as shown in FIG. 3(c), heat treatment at a second temperature that is equal to or higher than the first temperature and at which the polyamic acid is imidized is performed, and the barrier layer ( 14) to form. More specifically, the plastic film 16 is peeled from the membrane body 13, and the temperature is raised from room temperature to a second temperature, for example, 350°C to obtain a standard gas barrier film 10. At this time, it is preferable that the first temperature is 60 to 150°C, and the second temperature is 150 to 350°C. This is to reliably attach the barrier layer 14 to the substrate 12 and to imidize the polyamic acid.

Further, even if the barrier layer 14 obtained by heat treatment of the membrane body 13 at the second temperature was heated while being pressed against the substrate 12, the barrier layer 14 could not be adhered to the substrate 12. In addition, the method of adhering the barrier layer 14 obtained by heat-treating the membrane body 13 at a second temperature to the substrate 12 using an organic adhesive or the like increases the amount of water vapor passing through the inside of the adhesive to a negligible degree. Therefore, it cannot be applied. _{The water vapor transmission rate W S} (g/m ² /day) of the standard gas barrier film thus produced is the water vapor transmission rate of the barrier layer itself W _B (g/m ² /day), and the diameter of the circular opening 12a Let d, the effective diameter of the gas permeability measuring device to be calibrated is D,

W _S =W _B ×(d/D) ² (Equation 1)

It is represented by For example, if W _B is 2.0 × 10 ^-3 (g/m ² /day), d is 2 mm, and D is 90 mm, the water vapor transmission W _S of the standard gas barrier film is 1.0 × 10 ^-6 (g/m ² /day).

The variation in the water vapor permeability of each standard gas barrier film when mass-produced the standard gas barrier film is the difference in the permeability of water vapor permeability W _B of the barrier layer 14 within the film surface or from lot to lot, and the opening area of the opening 12a. Depends on _{The variation in the water vapor permeability W B} of the barrier layer 14 within the film surface or from lot to lot is about 10%. When the diameter of the opening is 1 mm and the processing accuracy is ±0.05 mm, the variation of the opening area of the opening 12a is about 10%. Even if the diameter of the opening 12a is increased to 20 mm, the processing accuracy is not changed to ±0.05 mm. Accordingly, when the diameter of the opening 12a is set from 1 mm to 20 mm, the variation in the opening area of the opening 12a can be reduced compared to the variation within the membrane surface _{of the barrier layer or for each rod of the water vapor transmission rate W B.}

Finally, it is possible to mass-produce a standard gas barrier film having the same water vapor permeability W _{S with a variation of 15% or less.} As described above, the standard gas barrier film 10 has a small individual difference, excellent reproducibility of water vapor permeability measurement, and since the barrier film 14 is a single layer, the behavior of water vapor transmission is simple, and it can withstand heating of 350°C. , Since the barrier film 14 can be adhered to the substrate 12 without using an adhesive, the reliability is high.

When the diameter of the opening 12a is smaller than 1 mm, the effect of the processing precision of the hole on the water vapor transmission rate of the standard gas barrier film increases. For example, when the diameter of the opening 12a is 0.5 mm and the processing accuracy is ±0.05 mm, the fluctuation of the opening area of the opening 12a is 21%, and the fluctuation of the water vapor transmission rate of the standard gas barrier film increases. . In addition, by using wire electric discharge machining or the like, it is possible to make the diameter machining precision of the opening portion ±0.05 mm or less, but it is not preferable to use wire electric discharge machining or the like for mass-produced products from the viewpoint of manufacturing cost. Further, when the diameter of the opening 12a is smaller than 1 mm, it becomes difficult to measure the inner diameter.

Hereinafter, the present invention will be described in more detail by examples. The content of the present invention is not limited to these examples. In addition, "%" represents "mass%" unless otherwise specified. In addition, the water vapor permeability of various samples was measured using the gas permeability measuring apparatus described in Patent Document 1.

Example

(Example 1)

First, 50 g of a homogeneous gel obtained by mixing 20 parts by mass of Li-type montmorillonite and 80 parts by mass of water (hereinafter sometimes referred to as “Li-type montmorillonite 20% gel”), and 105 g of N-methyl-2-pyrrolidone , After mixing 29.9 g of an 18% N-methyl-2-pyrrolidone solution of polyamic acid, it was passed through a sieve having a mesh of about 53 μm. Subsequently, the resulting mixed solution was applied on a PET film using a casting knife, and then dried at 60° C. to obtain a film body containing Li-type montmorillonite and polyamic acid, and a laminate composed of a PET film. On the other hand, a stainless steel plate (outer diameter 120 mm, thickness 0.5 mm) having both sides electropolished was prepared as a substrate. In this stainless steel plate, a cylindrical hole having a diameter of 20 mm (tolerance ±0.05 mm) was formed in the center. In addition, the electropolishing area was circular with a diameter of 120 mm.

Then, this laminate was hot pressed against the stainless steel plate so that the center of the stainless steel plate and the center of the laminate were substantially coincident in the direction in which the film body was in contact with the electropolished region. That is, the layered product was heated at a first temperature of 150° C. while pressing the layered product against the stainless steel plate so that the membrane body covered the openings, and the stainless steel plate and the layered product were integrated. At this time, the force applied to the laminate was 5 to 10 N, and the temperature of the stainless steel plate and the laminate was raised from room temperature to 150°C over 1 hour or more.

Next, the temperature of the stainless steel plate and the laminate was lowered to room temperature, the PET film was peeled off from the membrane body, and heat treatment was performed at a second temperature of 350°C. At this time, the temperature of the stainless steel plate and the membrane body was raised from room temperature to 350°C over 20 hours or more. In this way, a disk-shaped barrier layer having a diameter of about 30 mm and a thickness of about 30 μm is provided in the center, the diameter of the opening is 20 mm, and the mass of polyimide is 35% based on the sum of the masses of Li-type montmorillonite and polyimide. A gas barrier film was obtained. The ratio of the maximum diameter of the opening of the stainless steel plate to the thickness of the barrier layer was 20 mm/30 µm = 667. In addition, the water vapor permeability of the barrier layer itself was measured with a water vapor permeability measuring device (Technolox, Delta Palm) and found to be 2.0 x 10 ^-3 g/m ² /day. Therefore, when measured with a water vapor permeability measuring apparatus having an effective diameter of 90 mm, the water vapor permeability of this standard gas barrier film is 1.0 × 10 ^-4 g/m ² /day.

(Example 2)

A standard gas barrier film was prepared in the same manner as in Example 1, except that the diameter of the hole of the stainless steel plate was 6.5 mm (tolerance ±0.05 mm). A standard gas barrier film having a disk-shaped barrier layer having a diameter of about 30 mm and a thickness of about 30 µm was obtained in the center. The ratio of the maximum diameter of the opening of the stainless steel plate to the thickness of the barrier layer was 6.5 mm/30 µm = 217. When measured with a water vapor permeability measuring device having an effective diameter of 90 mm, the water vapor permeability of this standard gas barrier film is 1.1 × 10 ^-5 g/m ² /day.

(Example 3)

A standard gas barrier film was prepared in the same manner as in Example 1, except that the diameter of the hole of the stainless steel plate was 3.5 mm (tolerance ±0.05 mm). A standard gas barrier film having a disk-shaped barrier layer having a diameter of about 30 mm and a thickness of about 30 µm was obtained in the center. The ratio of the maximum diameter of the opening to the thickness of the barrier layer was 3.5 mm/30 µm = 117. When measured with a water vapor permeability measuring device having an effective diameter of 90 mm, the water vapor permeability of this standard gas barrier film is 3.1 × 10 ^-6 g/m ² /day.

(Example 4)

A standard gas barrier film was prepared in the same manner as in Example 1, except that the diameter of the hole of the stainless steel plate was 2.0 mm (tolerance ±0.05 mm). A standard gas barrier film having a disk-shaped barrier layer having a diameter of about 30 mm and a thickness of about 30 µm was obtained in the center. The ratio of the maximum diameter of the opening to the thickness of the barrier layer was 2.0 mm/30 μm=67. When measured with a water vapor permeability measuring device having an effective diameter of 90 mm, the water vapor permeability of this standard gas barrier film is 1.0 × 10 ^-6 g/m ² /day.

(Example 5)

In order to shorten the measurement time of the standard gas barrier film, it is effective to make the barrier layer thin. A standard gas barrier film was prepared in the same manner as in Example 1, except that the thickness of the barrier layer was about 10 μm. The ratio of the maximum diameter of the opening of the stainless steel plate to the thickness of the barrier layer was 20 mm/10 µm=2000. When measured with a water vapor permeability measuring device having an effective diameter of 90 mm, the water vapor permeability of this standard gas barrier film is 3.0 × 10 ^-4 g/m ² /day.

(Example 6)

A standard gas barrier film was prepared in the same manner as in Example 4, except that the diameter of the hole of the stainless steel plate was 1.2 mm (tolerance ±0.05 mm). The ratio of the maximum diameter of the opening of the stainless steel plate to the thickness of the barrier layer was 1.2 mm/10 µm = 120. When measured with a water vapor permeability measuring device having an effective diameter of 90 mm, the water vapor permeability of this standard gas barrier film is 1.1 × 10 ^-6 g/m ² /day.

From Examples 1 to 6, the ratio of the maximum diameter of the opening of the substrate to the thickness of the barrier layer is 67 to 2000, and when measured with a water vapor transmission rate measuring device having an effective diameter of 90 mm, the water vapor transmission rate of the standard gas barrier film is 1.0. A ^{standard gas barrier film of x10 -6} to 3.0 x 10 ^-4 g/m ² /day could be produced.

The effective diameter D of a commercially available water vapor permeability measuring device is 40 to 120 mm. In order to manufacture a standard gas barrier film having a small _{water vapor transmission rate W S} for a water vapor transmission rate measuring device having a small effective diameter D without changing the moisture vapor transmission rate W _{B of the barrier layer itself, the opening of the stainless steel plate is} It is necessary to reduce the diameter d. For a water vapor permeability measuring apparatus having an effective diameter D of 40 mm, when the diameter d of the opening of the stainless steel plate is 1 mm, and a standard gas barrier film is produced in the same manner as in Example 1, the water vapor transmission rate W _S is 1.3 × 10 ^-6 g A standard gas barrier film of /m ² /day can be produced.

(Verification experiment)

4 shows the result of measuring the water vapor signal of the standard gas barrier films obtained in Examples 1 to 3, that is, the ion current of m/z18 by the method described in Patent Document 1. In Fig. 4, the horizontal axis represents the elapsed time from when water vapor having a relative humidity of 90% at 40°C is introduced into the exposure side of the standard gas barrier film, and the vertical axis represents the ion current of m/z18 of the quadrupole mass spectrometer, That is, it is a signal of the amount of water vapor transmitted through the standard gas barrier film. This measurement was performed with a water vapor permeability measuring apparatus (Orwell Corporation, Omega Trans) having an effective diameter of 90 mm. In addition, the value of the background in the measurement is removed.

The water vapor signal gradually increased from about 120 hours, and showed a saturation tendency at 400 hours. The saturated ion current of the standard gas barrier film obtained in Example 1 was 1.5 × 10 ^-11 A. The saturated ion current of the standard gas barrier film obtained in Example 2 was 1.9 × 10 ^-12 A. The saturated ion current of the standard gas barrier film obtained in Example 3 was 3.7 × 10 ^-13 A.

5 is a diagram in which the saturated ion current of the standard gas barrier films obtained in Examples 1 to 3 is plotted against the opening area of the opening 12a. The saturated ion current of the standard gas barrier film was changed in proportion to the opening area of the opening 12a. If the result of Fig. 5 is fitted with a straight line passing through the origin,

I _sat =4.79×10 ^-8 ×A (Equation 2)

Was obtained. The difference between the saturated ion current I _sat calculated from this (Equation 2) and each measurement point in Examples 1 to 3 was 25% or less.

6 shows a comparison between the measurement result of FIG. 5 and the calibration result by the method described in Patent Document 1. The water vapor exposure conditions for the standard gas barrier film were a temperature of 40°C and a relative humidity of 90%. The method described in Patent Document 1 is a flow rate of water vapor introduced through a stainless steel porous sintered body ``Standard Conductance Element (SCE)'' whose molecular conductance is calibrated, and an ion current of m/z18 measured by a quadrupole mass spectrometer, that is, It is a method of comparing and correcting the signal of water vapor.

In Fig. 6, an ion current of m/z18 was plotted against the water vapor flow rate introduced through the SCE and the corresponding water vapor permeability obtained from the effective diameter of the device. The water vapor flow rate by SCE was adjusted by changing the upstream pressure of SCE. The water vapor permeability of the standard gas barrier films obtained in Examples 1 to 3 is located on a straight line of the calibration result by the method described in Patent Document 1. Therefore, it was confirmed that a standard gas barrier film having ^{a water vapor permeability of 10 -4} g/m ² /day or less at a temperature of 40°C and a relative humidity of 90% could be produced.

10… Standard gas barrier film
12... materials
12a... Opening
13... Membrane
14... Barrier layer
16... Plastic film
18... Laminate

Claims (8)

It is a standard gas barrier film used for calibration of water vapor permeability measuring devices,
A substrate having an opening,
A barrier layer provided on the substrate to cover the opening
Have,
The barrier layer contains Li-type montmorillonite nanoparticles and polyimide,
A standard gas barrier film in which the ratio of the maximum diameter of the opening to the thickness of the barrier layer is 50 to 2000. The standard gas barrier film according to claim 1, wherein the substrate and the barrier layer are directly bonded to each other. The standard gas barrier film according to claim 1 or 2, wherein the water vapor permeability at 40°C and 90% relative humidity is 10 ^-6 to 10 ^-3 g/m ^{2 /day.} The standard gas barrier film according to claim 1 or 2, wherein the substrate is a metal plate having an arithmetic mean roughness Ra of 2 nm or less on a surface opposite to the surface on which the barrier layer is provided. The standard gas barrier film according to claim 1 or 2, wherein the number of the openings is 1 to 10, and the maximum diameter of all the openings is 1 to 20 mm. The standard gas barrier film according to claim 1 or 2, wherein the mass of the polyimide relative to the sum of the masses of the Li-type montmorillonite and the polyimide is 20 to 40%. It is a method for producing a standard gas barrier film used for calibration of a water vapor transmission rate measuring apparatus, having a substrate having an opening and a barrier layer provided on the substrate so as to cover the opening,
A step of obtaining a laminate including a laminate of a film body containing Li-type montmorillonite nanoparticles and polyamic acid, and a plastic film, and
Heating the laminate at a first temperature while pressing the laminate against the substrate so that the membrane body covers the opening, and then heating at a second temperature equal to or higher than the first temperature and at which the polyamic acid is imidized
Method for producing a standard gas barrier film having. The method of claim 7, wherein the first temperature is 60 to 150°C, and the second temperature is 150 to 350°C.

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