Water vapor transmission rate measurement device and water vapor transmission rate measurement method

Abstract

To provide a water vapor transmission rate measurement device capable of improving measurement accuracy for a waver vapor transmission rate.SOLUTION: A water vapor transmission rate measurement device 1 is an apparatus for measuring a water vapor transmission rate of a film-like sample A, and comprises: a container 10 having a bottom wall 11 and a peripheral side wall 12 extending upward from the peripheral edge of the bottom wall, where a moisture-absorbing material B is arranged in a space surrounded by the bottom wall 11 and the peripheral side wall 12, and a sample A arranged on an upper end surface 13 of the peripheral side wall 12 so as to cover the space; a lid 20 having an opening 28 through which the sample A is exposed, which faces the upper end surface 13 of the peripheral side wall 12, and is fitted to an upper part of an outer peripheral surface of the peripheral side wall 12 of the container 10, where the sample is sandwiched in cooperation with the peripheral side wall 12 of the container 10; and a sealing mechanism 30 that seals an opening 28 of the lid 20.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an apparatus and method for measuring the water vapor transmission rate of a film-like sample. [Background technology]

[0002] Barrier films with low water vapor permeability are used as packaging materials for foods, medicines, electronic components, etc. For example, Non-Patent Documents 1 and 2 and Patent Document 1 disclose techniques for measuring the water vapor permeability of such film (sheet) samples.

[0003] In the moisture permeability test method (cup method) for moisture-proof packaging materials specified in JIS Z 0208:1976 described in Non-Patent Document 1 and ISO 2528:1995 described in Non-Patent Document 2, A cup having a bottom wall and a peripheral side wall, and a ring disposed on the peripheral side wall of the cup, - Moisture absorbent placed inside the cup, The sample piece is sandwiched between the circumferential wall of the cup and the ring. A groove is disposed on the periphery between the peripheral side wall of the cup and the ring, and sealing wax is poured into the groove to seal the periphery of the sample piece; After a specified time has elapsed in a specified humid environment, the mass is measured to measure the amount of moisture that penetrates into the cup through the sample piece and is absorbed by the moisture absorbent.

[0004] In the water vapor permeability measurement method described in Patent Document 1, - Using metal corrosion methods (e.g. calcium corrosion method), A sample is placed on a water vapor permeability measurement unit that contains calcium or the like and has a foil-shaped water vapor detection unit that detects water vapor, and the sample is sealed around the periphery with a sample sealant. After a predetermined time has passed in a predetermined humid environment, the location of corrosion in the water vapor detection part is measured, for example, by image processing, and the water vapor permeability of the sample is measured. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2014 / 119690 [Non-patent literature]

[0006] [Non-Patent Document 1] JIS Z 0208:1976, "Testing Methods for Determination of the Water Vapor Transmission Rate of Moisture-Proof Packaging Materials (Dish Method)", Japan Industrial Standards, March 1, 1976 [Non-patent document 2] ISO 2528:1995, “Sheet materials - Determination of water vapor transmission rate - Gravimetric (dish) method”, International Organization for Standardization, September 1, 1995. Summary of the Invention [Problem to be solved by the invention]

[0007] According to the findings of the present inventors, in the water vapor transmission rate measurement method described in Non-Patent Document 1, if the sample is thick or the surface of the sample is rough, even if the periphery of the sample between the peripheral side wall of the cup and the ring is sealed with sealing wax, the sealing ability of the sealing portion between the peripheral side wall of the cup, the ring, and the sample decreases. As a result, water vapor leaks from this sealing portion, and the measurement accuracy of the water vapor transmission rate of the sample decreases.

[0008] Furthermore, according to the findings of the present inventors, even in the water vapor transmission rate measurement method described in Patent Document 1, if the sample is thick or the surface of the sample is rough, even if the periphery of the sample is sealed with a sample sealant, the sealing ability of the sealed portion between the sample sealant and the sample decreases, resulting in water vapor leaking from the sealed portion and decreasing the measurement accuracy of the water vapor transmission rate of the sample.

[0009] An object of the present invention is to provide a water vapor transmission rate measuring device and a water vapor transmission rate measuring method that improve the accuracy of measuring water vapor transmission rates. [Means for solving the problem]

[0010] The water vapor permeability measuring device of the present invention is a device for measuring the water vapor permeability of a film-like sample, and comprises a container having a bottom wall and a peripheral side wall extending upward around the periphery of the bottom wall, wherein a moisture-absorbing material is placed in the space surrounded by the bottom wall and the peripheral side wall, and the sample is placed on the upper end surface of the peripheral side wall so as to cover the space; a lid having an opening through which the sample is exposed, facing the upper end surface of the peripheral side wall, and fitting with the upper part of the outer circumferential surface of the peripheral side wall of the container, wherein the sample is sandwiched in cooperation with the peripheral side wall of the container; and a sealing mechanism for sealing the opening of the lid.

[0011] A water vapor transmission rate measuring method according to the present invention is a water vapor transmission rate measuring method using the water vapor transmission rate measuring device described above, and includes a first step of placing the moisture absorbent material in the container, fitting the lid to the container to sandwich the sample between the container and the lid, and measuring a change in mass of the moisture absorbent material after a predetermined time has passed in a predetermined humidity environment, thereby measuring the amount of water vapor transmitted through the sample exposed to the opening of the lid and the amount of water vapor leaking from a sealing portion that is a fitting portion between the lid and the outer peripheral surface of the peripheral side wall of the container; a second step of fitting the lid to the container to sandwich the sample between the container and the lid, further sealing the opening of the lid with the sealing mechanism, and measuring the change in mass of the moisture absorbent material after the predetermined time has elapsed in the predetermined humidity environment, thereby measuring the amount of water vapor permeation leaking from the sealing portion, which is the fitting portion between the lid and the outer peripheral surface of the peripheral side wall of the container; and a third step of subtracting the measurement value of the second step from the measurement value of the first step to obtain the amount of water vapor permeation through the sample, and calculating the water vapor permeability based on the obtained amount of water vapor permeation. [Effects of the Invention]

[0012] According to the present invention, the measurement accuracy of water vapor transmission rate can be improved. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a cross-sectional view showing the configuration of a water vapor transmission rate measuring device according to an embodiment of the present invention. [Figure 2A] FIG. 2 is a diagram showing a first step in the water vapor transmission rate measurement method according to the present embodiment. [Figure 2B] FIG. 3 is a diagram showing a second step in the water vapor transmission rate measurement method according to the present embodiment. [Figure 3] FIG. 10 is a perspective view showing the configuration of a water vapor transmission rate measuring device according to a modified example of the present embodiment. [Figure 4A] FIG. 4 is a diagram showing a first step in a water vapor transmission rate measurement method according to a modified example of the present embodiment. [Figure 4B] FIG. 10 is a diagram showing a second step in the water vapor transmission rate measurement method according to a modified example of the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] An example of an embodiment of the present invention will be described below with reference to the accompanying drawings. The same or equivalent parts in each drawing are designated by the same reference numerals. For convenience, hatching and reference numerals may be omitted. In such cases, reference should be made to other drawings.

[0015] (Water vapor transmission rate measuring device) Fig. 1 is a cross-sectional view showing the configuration of a water vapor transmission rate measuring device according to this embodiment. The water vapor transmission rate measuring device 1 shown in Fig. 1 is a device for measuring the water vapor transmission rate of a film-like sample A. The water vapor transmission rate measuring device 1 includes a container 10, a lid 20, and a sealing mechanism 30.

[0016] The container 10, the lid 20, and the sealing mechanism 30 each have, for example, a circular shape when viewed from above. The container 10, the lid 20, and the sealing mechanism 30 may be made of any material that has a hermetic (sealing) property. Such materials are not particularly limited, but examples thereof include metal, resin, glass, and ceramic.

[0017] The container 10 has a bottom wall 11 and a peripheral side wall 12 extending upward from the periphery of the bottom wall 11. A sample A is placed on an upper end surface 13 of the peripheral side wall 12 so as to cover the space enclosed by the bottom wall 11 and the peripheral side wall 12. A moisture-absorbing material B is also placed in the space enclosed by the bottom wall 11 and the peripheral side wall 12. A fitting portion 15 such as a screw that fits with a lid 20 is provided on the outer periphery of the peripheral side wall 12 on the side of the upper end surface 13.

[0018] The lid 20 faces the upper end surface 13 of the peripheral sidewall 12 of the container 10 and cooperates with the peripheral sidewall 12 of the container 10 to sandwich the sample A. The lid 20 has an opening 28 through which the sample A is exposed. A fitting portion 25 such as a screw that fits with the container 10 is provided at the lower part of the inner peripheral surface of the lid 20. The fitting portion 25 on the inner peripheral surface of the lid 20 fits with a fitting portion 15 on the outer peripheral surface of the peripheral sidewall 12 of the container 10. In addition, a fitting portion 26 such as a screw that fits with a sealing mechanism 30 is provided at the upper part of the outer peripheral surface of the lid 20.

[0019] The sealing mechanism 30 seals the opening 28 of the lid 20. The sealing mechanism 30 is, for example, a lid that covers the opening 28 of the lid 20. A sealing member 40, for example, in a ring shape, is disposed between the lid serving as the sealing mechanism 30 and the lid 20. The material of the sealing member 40 is not particularly limited, but examples thereof include rubber, metal, silicon, and PTFE. A fitting portion 36, such as a screw, that fits with the lid 20 is provided at the bottom of the inner peripheral surface of the lid serving as the sealing mechanism 30. The fitting portion 36 on the inner peripheral surface of the lid serving as the sealing mechanism 30 fits with the fitting portion 26 on the outer peripheral surface of the lid 20.

[0020] (Water vapor transmission rate measurement method) Next, a water vapor transmission rate measuring method according to this embodiment will be described with reference to Figures 2A and 2B, which uses the above-described water vapor transmission rate measuring device 1. Figure 2A is a diagram showing a first step in the water vapor transmission rate measuring method according to this embodiment, and Figure 2B is a diagram showing a second step in the water vapor transmission rate measuring method according to this embodiment.

[0021] First, as shown in Figure 2A, moisture absorbent material B is placed in container 10, and lid 20 is fitted onto container 10 to sandwich sample A between container 10 and lid 20. Next, after a predetermined time has elapsed in a predetermined humidity environment, the change in mass of moisture absorbent material B is measured (first step). For example, the difference between the mass of container 10 before the predetermined time has elapsed and the mass of container 10 after the predetermined time has elapsed is measured.

[0022] Here, if sample A becomes thicker or the surface of sample A becomes rougher, the sealing property of the sealing portion (sealing portion) between the upper end surface 13 of the peripheral side wall 12 of the container 10, sample A, and the lid 20 at the fitting portion 15-25 between the peripheral side wall 12 of the container 10 and the lid 20 will be reduced.

[0023] In this case, the first step involves measuring the amount of water vapor permeating through sample A exposed to the opening 28 of the lid 20 and the amount of water vapor permeating through the sealing portion at the fitting portion 15-25 between the lid 20 and the peripheral side wall 12 of the container 10 (see arrows).

[0024] Next, as shown in Figure 2B, moisture absorbent material B is placed in container 10, and lid 20 is fitted onto container 10 to sandwich sample A between container 10 and lid 20. Furthermore, opening 28 of lid 20 is sealed with sealing mechanism 30. Next, after a predetermined time has elapsed in a predetermined humidity environment, the change in mass of moisture absorbent material B is measured (second step). For example, the difference between the mass of container 10 before the predetermined time has elapsed and the mass of container 10 after the predetermined time has elapsed is measured.

[0025] Here, the sealing portion (seal portion) at the fitting portions 26-36 between the lid 20 and the sealing mechanism 30 has high sealing performance due to the sealing member 40. As a result, in the second step, only the amount of water vapor permeation leaking from the sealing portion at the fitting portions 15-25 between the lid 20 and the peripheral side wall 12 of the container 10 is measured (see arrows).

[0026] The order of the first and second steps may be reversed, i.e., the second step may be carried out first, followed by the first step.

[0027] Then, the measured value in the second step is subtracted from the measured value in the first step to obtain the amount of water vapor transmitted through sample A, and the water vapor transmission rate is calculated based on the obtained amount of water vapor transmitted (third step).

[0028] As described above, according to the water vapor permeability measuring device 1 and water vapor permeability measuring method of this embodiment, if the thickness of sample A or the surface of sample A becomes rough, the sealing property of the sealing portion between the upper end surface 13 of the peripheral side wall 12 of the container 10, sample A, and the lid 20 at the fitting portion 15-25 between the lid 20 and the peripheral side wall 12 of the container 10 will decrease, and even if water vapor leaks from this sealing portion, the amount of water vapor leaking from the sealing portion can be subtracted to improve the measurement accuracy of the water vapor permeability of the sample.

[0029] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and various changes and modifications are possible.

[0030] (Variation) Fig. 3 is a perspective view showing the configuration of a water vapor transmission rate measuring device according to a modified example of this embodiment. Fig. 4A is a diagram showing a first step in the water vapor transmission rate measuring method according to a modified example of this embodiment, and Fig. 4B is a diagram showing a second step in the water vapor transmission rate measuring method according to the modified example of this embodiment.

[0031] In the water vapor permeability measuring device 1 of the above-described embodiment, the lid 20 has one large-diameter opening 28. As shown in Fig. 3, in a modified water vapor permeability measuring device 1A, the lid 20A may have multiple small-diameter openings 28.

[0032] In the water vapor transmission rate measuring device 1 of the above-described embodiment, the sealing mechanism 30 is a lid. As shown in Fig. 3, in a modified water vapor transmission rate measuring device 1A, the sealing mechanism 30A may be an adhesive film that seals the multiple openings 28 of the lid 20. The adhesive film is not particularly limited, and any known adhesive film having hermetic (sealing) properties can be used.

[0033] 4A, in the modified water vapor transmission rate measurement method using the modified water vapor transmission rate measurement device 1A, moisture absorbent material B is placed in container 10, and lid 20A is fitted to container 10 to sandwich sample A between container 10 and lid 20A. Then, after a predetermined time has elapsed in a predetermined humidity environment, the change in mass of moisture absorbent material B is measured (first step). As a result, in the first step, the amount of water vapor permeating through sample A exposed to opening 28 in lid 20A and the amount of water vapor permeating leaking from the sealed portion at fitting portion 15-25 between lid 20A and peripheral side wall 12 of container 10 are measured (see arrows).

[0034] 4B, moisture-absorbent material B is placed in container 10, and lid 20A is fitted to container 10 to sandwich sample A between container 10 and lid 20A. Opening 28 of lid 20A is then sealed with sealing mechanism 30A. After a predetermined time has elapsed in a predetermined humidity environment, the change in mass of moisture-absorbent material B is measured (second step). This allows the amount of water vapor permeating through the sealed portion at fitting portion 15-25 between lid 20A and peripheral side wall 12 of container 10 to be measured (see arrows).

[0035] Then, the measured value in the second step is subtracted from the measured value in the first step to obtain the amount of water vapor transmitted through sample A, and the water vapor transmission rate is calculated based on the obtained amount of water vapor transmitted (third step).

[0036] Even in this modified water vapor permeability measuring device 1A and water vapor permeability measuring method, if sample A becomes thicker or the surface of sample A becomes rougher, the sealing property of the sealing portion between the upper end surface 13 of the peripheral side wall 12 of the container 10, sample A, and lid 20A at the fitting portion 15-25 between the lid 20A and the peripheral side wall 12 of the container 10 will decrease, and even if water vapor leaks from this sealing portion, the amount of water vapor leaking from the sealing portion can be subtracted to improve the measurement accuracy of the water vapor permeability of the sample. [Explanation of symbols]

[0037] 1,1A Water Vapor Transmission Rate Measuring Device 10 containers 11 Bottom wall 12 Peripheral wall 13 Upper end surface 15 Fitting part 20,20A lid 25,26 Mating part 28 Aperture 30,30A sealing mechanism 36 Fitting part 40 Sealing member Sample A B Moisture absorbing material

Claims

1. An apparatus for measuring the water vapor transmission rate of a film-like sample, a container having a bottom wall and a peripheral side wall extending upward from the periphery of the bottom wall, wherein a moisture-absorbing material is disposed in a space surrounded by the bottom wall and the peripheral side wall, and the sample is disposed on an upper end surface of the peripheral side wall so as to cover the space; a lid having an opening through which the sample is exposed, facing the upper end surface of the peripheral side wall, and fitting with an upper portion of the outer circumferential surface of the peripheral side wall of the container, the lid cooperating with the peripheral side wall of the container to sandwich the sample; a sealing mechanism that seals the opening of the lid; A water vapor transmission rate measuring device comprising:

2. 2. The water vapor transmission rate measuring device according to claim 1, wherein the sealing mechanism is a lid that covers the opening of the lid and fits onto an upper portion of the outer circumferential surface of the lid.

3. A method for measuring water vapor transmission rate using the water vapor transmission rate measuring device according to claim 1, a first step of placing the moisture absorbent material in the container, fitting the lid to the container to sandwich the sample between the container and the lid, and measuring a change in mass of the moisture absorbent material after a predetermined time has passed in a predetermined humidity environment, thereby measuring the amount of water vapor permeating through the sample exposed at the opening of the lid and the amount of water vapor leaking from a sealing portion that is a fitting portion between the lid and the outer peripheral surface of the peripheral side wall of the container; a second step of placing the moisture absorbent material in the container, fitting the lid to the container to sandwich the sample between the container and the lid, sealing the opening of the lid with the sealing mechanism, and measuring the amount of water vapor permeating through a sealing portion, which is a fitting portion between the lid and the outer peripheral surface of the peripheral side wall of the container, by measuring a change in mass of the moisture absorbent material after the predetermined time has elapsed in the predetermined humidity environment; a third step of subtracting the measured value of the second step from the measured value of the first step to obtain the amount of water vapor transmitted through the sample, and calculating the water vapor transmission rate based on the obtained amount of water vapor transmitted; A method for measuring water vapor transmission rate, comprising:

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