Measuring instrument and measuring method

Abstract

To provide a measuring instrument that can measure gas barrier performance in a simple and low-cost manner and can include a paper-based sheet as a measurement target.SOLUTION: An instrument used for measuring the gas barrier performance of a sheet includes a body part 10 that has an opening part 10h and a hollow space 10a connected to the outside through the opening part 10h, and a lid 20 that can be detachably attached to the opening part 10h of the body part 10 and is held between the opening part 10h of the body part 10 and a top surface 20b with a sheet sandwiched in between. The lid 20 has a connecting opening 20h formed so as to connect the front and back of the top surface 20b. The body part 10 has a first chamber and a second chamber separated by a partition wall and connected in a space above the partition wall in the hollow space 10a.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a measuring device and a measuring method. [Background technology]

[0002] Packaging sheets used in food packaging are required to have the ability to reduce oxygen transmission (oxygen gas barrier performance) and high moisture resistance (water vapor barrier properties) to prevent oxidation and deterioration of the contents.

[0003] Conventionally, the gas barrier performance of the above-mentioned packaging sheets has been measured using the plastic film and sheet gas permeability test method (JIS K 7126-1 (differential pressure method), 2 (constant pressure method): 2006). This test method involves placing a test piece between the chambers of a gas permeation cell, and then evaluating the gas barrier performance of the test piece based on the movement of gas from one chamber to the other.

[0004] Furthermore, Patent Document 1 describes that the oxygen permeability of the sheet is measured using OX-TRAN2 / 21 manufactured by MOCON. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2014-173202 A DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0006] However, the above-mentioned test method based on the JIS standard is intended for plastic sheets, not for sheets with a paper substrate. In addition, the device described in Patent Document 1 also has a problem that, since the measurement target is a plastic sheet, it is difficult to maintain airtightness when measuring a paper substrate. In addition, when any of the above-mentioned methods are used, there are problems such as the need for a gas delivery mechanism, making the device large-scale, and the high cost required for one measurement.

[0007] Therefore, an object of the present invention is to provide a measuring device and a measuring method that can measure gas barrier performance easily and at low cost, and that can also measure sheets whose substrate is made of paper. [Means for solving the problem]

[0008] The measuring instrument of the present invention is an instrument used to measure the gas barrier performance of a sheet, and comprises a main body having an opening and a hollow space connected to the outside through the opening, and a lid which is removably attached to the opening of the main body and holds a sheet between the opening of the main body and a top surface, the lid having a communication port formed in the top surface connecting the front and back, and the main body having a first chamber and a second chamber within the hollow space which are separated by a partition and connected by a space above the partition.

[0009] The measuring method of the present invention is a method for measuring the gas barrier performance of a sheet, and is characterized in that an alkaline aqueous solution and a pyrogallol aqueous solution are placed in a container having an opening and a hollow space communicating with the outside through the opening, in a separated state, a test piece formed of the sheet whose gas barrier performance is to be measured is placed so as to cover the opening of the container, and the test piece is fixed to the container so that air does not enter the container between the container and the test piece to form a measuring device, a pre-reaction container weight of this measuring device is measured, and after measuring the pre-reaction container weight, the alkaline aqueous solution and the pyrogallol aqueous solution are mixed in the container of the measuring device, and then the measuring device is placed in a constant temperature and humidity chamber and left to stand for a predetermined time, and after the predetermined time has elapsed, a post-reaction container weight of the measuring device is measured, and the oxygen permeability of the sheet is calculated based on the difference between the post-reaction container weight and the pre-reaction container weight. Effect of the Invention

[0010] According to the measuring device and measuring method of the present invention, the gas barrier performance of a sheet can be appropriately measured simply and at low cost. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is a schematic perspective view of the measuring instrument 1 of the first embodiment with a test piece S attached thereto. [Diagram 2] FIG. 1 is a schematic exploded explanatory view of a measuring instrument 1 according to a first embodiment. [Diagram 3] 3(A) is a schematic vertical cross-sectional view of FIG. 1, and FIG. 3(B) is a schematic cross-sectional view taken along line BB of FIG. 3(A). [Figure 4] 1 is a schematic explanatory diagram of a method for preparing a mixed liquid R3 in the measurement device 1 of embodiment 1. FIG. [Diagram 5] 10(A) and 10(B) are schematic vertical cross-sectional views showing modified examples of the main body 10 in the measurement instrument 1 of the first embodiment. [Figure 6] FIG. 13 is a diagram showing an example of an experimental result. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The measuring instrument and measuring method of the present invention will be described with examples. However, the present invention is not limited to the following examples. In the following Figs. 1 to 5, the same parts are given the same reference numerals and their description may be omitted. In addition, in the drawings, for convenience of description, the structure of each part may be appropriately simplified and the dimensional ratio of each part may be shown diagrammatically, different from the actual one. In addition, the descriptions of each embodiment can be mutually referenced unless otherwise specified.

[0013] <Embodiment 1: Measuring Instrument> Fig. 1 is a schematic perspective view showing an example of the configuration of the measuring instrument of the present invention in a state where a test piece to be measured is attached. Fig. 2 is a schematic exploded explanatory view thereof, Fig. 3(A) is a schematic vertical sectional view thereof, and Fig. 3(B) is a schematic sectional view taken along line BB in Fig. 3(A). As shown in Figs. 1 to 3, the measuring instrument 1 of this embodiment includes a main body 10, a lid 20, a container 13, and a movement prevention member 14. Note that the presence or absence of the container 13 and the movement prevention member 14 is optional in the measuring instrument 1 of this embodiment, and the measuring instrument 1 does not necessarily have to include them.

[0014] The main body 10 is a container having an opening 10h at one end (the upper end in Figs. 1 to 3) and has a hollow space (hereinafter referred to as "storage space 10a") inside that is connected to the outside through this opening 10h. That is, the main body 10 has a structure that allows an object to be placed in the storage space 10a through the opening 10 formed at one end. An opening 12 having an opening 10h at the upper end is provided at one end of the main body 10. This opening 12 is a portion to which the lid 20 is attached, and may have a male screw 12b formed on the side surface, for example.

[0015] The shape of the main body 10 is not particularly limited as long as it has an opening and a hollow space that communicates with the outside through the opening.

[0016] The lid 20 is detachably attached to the main body 10. The lid 20 has a communication port 20h formed on the top surface 20b to communicate the front and back. The lid 20 may have, for example, a side wall 20a continuing from the periphery of the top surface 20b, and a female thread 20c formed on the inner surface of the side wall 20a. With this configuration, when the lid 20 is placed over the opening 12 of the main body 10 and rotated, the male thread 12b of the opening 12 is engaged with the female thread 20c of the side wall 20a, and the lid 20 can be attached to the opening 12. When the lid 20 is rotated in the opposite direction, the male thread 12b of the opening 12 is disengaged from the female thread 20c of the side wall 20a, and the lid 20 can be removed from the opening 12.

[0017] The communication opening 20h is formed so as to be located at a position corresponding to the opening 10h of the main body 10 when the lid 20 is attached to the opening 12 of the main body 10. That is, the communication opening 20h is formed so that the storage space 10a of the main body 10 communicates with the outside through the communication opening 20h of the lid 20 and the opening 10h of the main body 10 when the lid 20 is attached to the opening 12 of the main body 10. The communication opening 20h may be formed so as to be smaller in size than the opening 10h (see FIG. 3). Specifically, the communication opening 20h may be formed so that the top surface 20b is located near the outer edge of the lid 20 and at a position corresponding to the upper edge 12t of the opening 10h of the main body 10 when the lid 20 is attached to the opening 12 of the main body 10.

[0018] The cover 20 can hold a sheet to be measured between the opening 10h and the top surface 20b of the main body 10. In the present invention, the sheet to be measured is not particularly limited and can include various sheets whose gas barrier performance is to be measured. For example, a sheet that is required to have a function of reducing oxygen transmission (oxygen gas barrier performance) to prevent oxidation or deterioration of the contents when wrapped in a specific object can be used as the sheet for measuring the gas barrier performance in the present invention. Examples of such sheets include resin sheets made of polyethylene, polypropylene, etc., laminated paper in which a polyethylene film or the like is laminated on paper, and barrier-coated paper in which a gas barrier layer having a gas barrier function is provided on paper. In addition, the measuring instrument of the present invention mainly measures oxygen permeability (oxygen gas barrier performance), but can also be used to measure the permeability of other gases such as water vapor.

[0019] Barrier-coated paper is generally a sheet member having a gas barrier layer having a gas barrier function provided on the surface of a paper base material, that is, the barrier-coated paper is a sheet-like member having gas barrier properties even though the base material is made of paper.

[0020] The method for forming the gas barrier layer of the barrier-coated paper and its components are not particularly limited. For example, the gas barrier layer can be formed by applying a liquid containing a water-dispersible barrier coating agent (e.g., one or more compounds selected from water-dispersible polyolefin resins, acrylic resins, styrene resins, etc.) to the surface of the paper substrate.

[0021] 1 to 3 show a test piece S made of a sheet to be measured. Details of the test piece S will be described later.

[0022] The size of the opening 10h of the main body 10 is not particularly limited. By increasing the area of ​​the opening 10h, the area for measuring the gas barrier performance of the test piece S becomes larger, and therefore the measurement accuracy can be improved. However, it is preferable to keep the area of ​​the opening 10h within a range in which the load on the test piece S is not too large. Specifically, it is preferable to adjust the area of ​​the opening 10h so that the force applied to the test piece S due to the pressure difference between the inside and outside of the storage space 10a of the main body 10 is not greater than the fixing force by the lid 20 (for example, a maximum of 10 kgf). The area of ​​the opening 10h is, for example, 5 cm 2 More than 80cm 2 Below, 5cm 2 More than 50cm 2 Below, 10cm 2 More than 50cm 2 For example, the load applied to the test piece S can be calculated by the following formula. W = {(P0-P) / P0} × A × T W: Load applied to test piece S (kgf) P0: Atmospheric pressure (1kgf / cm 2 ) P: Pressure inside the main body 10 (kgf / cm 2 ) A: Area of ​​the opening 10h of the main body 10 (cm 2 ) T: Atmospheric pressure (1kgf / cm 2 )

[0023] For example, if the pressure difference is 0.21 atm (0.21 kgf / cm 2 ), and the pressure inside the main body 10 is 0.79 kgf / cm 2 , the area of ​​the opening 10h is 13.2cm 2 In this case, the load W applied to the test piece S is 2.77 kgf. Also, assuming other conditions are the same, the area of ​​the opening 10h is 78.5 cm 2 In this case, the load W applied to the test piece S is 16.5 kgf.

[0024] Figures 1 to 3 show an example in which the lid portion 20 is attached to the main body portion 10 by a screw connection, but the configuration for attaching the lid portion 20 to the main body portion 10 may be any configuration that can hold the test specimen S between the two and maintain a certain degree of airtightness between the inside and the outside of the storage space 10a of the main body portion 10 while holding the test specimen S, and for example, a configuration having a commercially available crimper structure may be adopted.

[0025] There is no particular limitation on the area of ​​the communication port 20h of the lid 20. The present invention is intended to measure the amount of gas (which may include moisture in the air) that permeates the test piece S, and since the movement of this gas through the test piece S is very slow, the amount of gas to be measured is unlikely to be affected by the area of ​​the communication port 20h.

[0026] The size of the communication opening 20h may be determined, for example, in relation to the opening 10h of the main body 10. The number of communication openings 20h is not particularly limited, and may be one or more as shown in Figures 1 and 2. The shape of the communication opening 20h is also not particularly limited, and may be circular as shown in Figures 1 and 2, or may be other shapes such as elliptical or rectangular.

[0027] The main body 10 and the lid 20 may be produced, for example, by forming the communication opening 20h in the lid of a glass jar such as a commercially available jam jar.

[0028] As shown in FIGS. 1 to 3, the measuring device 1 of this embodiment further includes a container 13 and a movement prevention member 14 that are accommodated in the accommodation space 10a of the main body portion 10. As shown in FIG.

[0029] As shown in Figs. 1 to 3, the container 13 is a bottomed cylindrical container having an opening at the top end, and has a function of storing liquid in its internal space 13c. The container 13 is large enough to be placed in the storage space 10a through the opening 10h of the main body 10, and can be arranged upright with its bottom surface 13b in contact with the inner bottom surface of the main body 10. As shown in Fig. 4 described later, the container 13 is large enough to be tilted in the storage space 10a. Specifically, when the main body 10 is placed on a horizontal table or the like, the container 13 is large enough to be arranged upright in the storage space 10a without spilling liquid in the space 13c of the container 13. The container 13 is large enough that when the main body 10 is tilted while it is stored in the storage space 10a, the container 13 can be tilted or turned over in the storage space 10a, and the liquid in the space 13c can be supplied from the opening at the top end into the storage space 10a. In this example, space 13c of container 13 corresponds to the first chamber in the measuring instrument of the present invention, the space other than the space occupied by container 13 in storage space 10a corresponds to the second chamber in the measuring instrument of the present invention, and the outer wall of container 13 corresponds to the partition in the measuring instrument of the present invention.

[0030] As shown in Figs. 2 and 3, the movement prevention member 14 is disposed on the inner bottom surface of the storage space 10a of the main body 10. The movement prevention member 14 is provided to restrict the movement of the container 13 along the inner bottom surface of the storage space 10a of the main body 10. That is, the movement prevention means 14 is provided to prevent the container 13 from sliding and moving on the inner bottom surface of the main body 10 when the main body 10 is tilted in a state in which the container 13 is stored, and to cause the container 13 to tilt (see Fig. 4). For example, as shown in Figs. 1 to 3, when a bar is used as the movement prevention member 14, it can be inserted into the storage space 10a through the opening 10h of the main body 10 and laid on the inner bottom surface, and further, a bar having a length such that both ends of the bar come into contact with the inner side surface of the storage space 10a when the main body 10 is tilted and the movement stops can be used as the movement prevention member 14. If such a movement prevention member 14 is placed in the accommodation space 10a of the main body 10 together with the container 13 and the main body 10 is tilted, even if the container 13 moves along the inner bottom surface of the accommodation space 10a of the main body 10, the movement prevention member 14 can prevent the container 13 from moving and tilt the container 13. That is, if the container 13 comes into contact with the movement prevention member 14, the container 13 can be brought from an inverted state (the state in FIG. 4(A)) to a lying state (the state in FIG. 4(B) and FIG. 4(C)) with the contact point as a fulcrum. The shape, size, etc. of the movement prevention member 14 are not particularly limited as long as it can perform the above-mentioned function.

[0031] As mentioned above, in the measuring instrument 1 of this embodiment, the presence or absence of the movement prevention member 14 is optional, and if it is possible to tilt the container 13 without the movement prevention member 14, it is not necessary to provide the movement prevention member 14.

[0032] In the measuring device 1 of this embodiment, instead of providing the container 13 and the movement prevention means 14 in the accommodation space 10a of the main body 10, a partition wall 14 may be provided to divide the lower part of the accommodation space 10a of the main body 10 in two as shown in Fig. 5(A). In this example, one side of the partition wall 14 (e.g., the left side in Fig. 5(A)) corresponds to the first chamber in the measuring device of the present invention, and the other side (e.g., the right side in Fig. 5(A)) corresponds to the second chamber in the measuring device of the present invention. Note that, as shown in Fig. 5(B), one surface of the partition wall 14 (the left surface in Fig. 5(B)) may be an inclined surface.

[0033] The measuring device 1 of this embodiment can be manufactured simply and at low cost by, for example, forming a communication port 20h in the lid of a commercially available jam jar as described above to prepare the main body 10 and the lid 20, and then arranging a container 13 in the storage space 10a of the main body 10 as shown in Figures 1 to 3, or by providing a partition wall 14 in the storage space 10a of the main body 10 as shown in Figure 5 to form a first chamber and a second chamber in the storage space 10a of the main body 10. Moreover, it has been demonstrated in the examples described later that the measuring device 1 of this embodiment can measure the gas barrier performance of a sheet, including a sheet whose base material is made of paper, simply and at low cost without requiring a gas delivery mechanism or the like.

[0034] As shown in Fig. 1 and Fig. 3, in the measuring instrument 1 of this embodiment, after the lid part 20 is attached to the main body part 10, a sealing tape T may be wrapped around the lid part 20 and the main body part 10 to connect them. By wrapping the sealing tape T, it is possible to prevent air from entering between the lid part 20 and the main body part 10. The material of the sealing tape T is not particularly limited, but it is preferable that the sealing tape T has high gas barrier performance and adhesion. For example, the sealing tape T may be made of polytetrafluoroethylene.

[0035] In the measuring instrument 1 of the present embodiment, since it is desirable to keep the test piece S airtight when the test piece S is sandwiched between the lid part 20 and the main body part 10, a leak prevention means 30 may be provided to further increase airtightness. The leak prevention means 30 may be, for example, a ring-shaped seal member 30a disposed between the lid part 20 and the upper end edge 12t of the opening 12 of the main body part 10, as shown in Figs. 2 and 3. By providing such a leak prevention means 30, air leakage can be effectively suppressed when the test piece S is sandwiched between the lid part 20 and the main body part 10. The leak prevention means 30 is preferably a member that can be elastically deformed when an external force is applied. Examples of the leak prevention means 30 (seal member 30a) include packing made of nitrile rubber (NBR), polyvinyl chloride, fluororesin, polyamide resin, polyethylene resin, butyl rubber (IIR), silicone rubber (VMQ), fluororubber (FKM), ethylene propylene diene rubber (EPDM), urethane rubber, and the like. It is also possible to form a layered leak prevention means 30 by applying liquid polyvinyl chloride or the like to the inner wall peripheral portion of the lid portion 20 and the upper edge 12t of the opening 12 by coating or the like. In the case where a commercially available glass bottle such as a jam jar is used as the main body portion 10 and the lid portion 20 and the glass bottle has the above-mentioned layered polyvinyl chloride or the like, this may be used as the leak prevention means 30.

[0036] In addition, when the test piece S is made of barrier-coated paper or laminated paper, it is desirable to provide the leak prevention means 30 so as to be in contact with the paper substrate. In the case of barrier-coated paper or laminated paper, compared with resin sheets such as polyfilm, the paper substrate has voids due to its structure, so that gas can easily pass through the inside of the paper substrate. Therefore, if the leak prevention means 30 is brought into contact with the paper substrate so that the pressing force when attaching the lid part 20 to the main body part 10 is applied to the paper substrate, this pressure may cause the structure of the paper substrate to become dense, thereby maintaining airtightness.

[0037] Furthermore, when the test piece S is made of barrier-coated paper or laminated paper, it is preferable to arrange the test piece S so that the coated surface coated with the gas barrier layer does not come into contact with the leak prevention means 30 (sealing member 30a). In other words, it is preferable to arrange the leak prevention means 30 (sealing member 30a) so that it comes into contact with the paper substrate of the test piece S. Then, when the test piece S and the leak prevention means 30 (sealing member 30a) are arranged in order from the bottom between the lid part 20 and the main body part 10 in a state where the lid part 20 is attached to the main body part 10, it is preferable to arrange the test piece S so that the coated surface of the test piece S is located downward (the lower side in FIG. 1) and the paper substrate of the test piece S faces upward (the upper side in FIG. 1, i.e., the lid part 20 side).

[0038] <Embodiment 2: Measurement method> Next, with reference to Fig. 4, an example of the measurement method of the present invention will be described using the measurement device shown in Fig. 1 to Fig. 3. However, the measurement method of the present invention is not limited to this example, and may be carried out using, for example, a measurement device other than the measurement device shown in Fig. 1 to Fig. 3.

[0039] First, a test piece S is formed from the sheet to be measured. The test piece S is desirably formed so that it has a shape similar to the opening 10h of the main body 10 and is slightly larger than the opening 10h of the main body 10. Specifically, for example, the test piece S is formed to a size that allows the opening 10h of the main body 10 to be completely covered by the test piece S when the test piece S is placed on the upper edge 12t of the opening 12.

[0040] Next, the container 13 containing the pyrogallol aqueous solution R2 is placed in the storage space 10a of the main body 10, and then the movement prevention member 14 is placed on the inner bottom surface of the storage space 10a of the main body 10. Next, an alkaline aqueous solution R1 such as potassium hydroxide is placed in the storage space 10a of the main body 10. At this time, care should be taken not to let the alkaline aqueous solution R1 enter the container 13. Note that the operation of placing the container 13 containing the pyrogallol aqueous solution R2 and the movement prevention member 14 in the storage space 10a of the main body 10 and the operation of putting the alkaline aqueous solution into the storage space 10a of the main body 10 may be performed in the reverse order from that described above.

[0041] The alkaline aqueous solution R1 may be any liquid as long as it is capable of exhibiting an oxygen absorbing function when mixed with the pyrogallol aqueous solution R2. For example, the alkaline aqueous solution may be an aqueous solution of potassium hydroxide, an aqueous solution of sodium hydroxide, an aqueous solution of calcium hydroxide, an aqueous solution of barium hydroxide, an aqueous solution of sodium carbonate, etc.

[0042] The amounts of the alkaline aqueous solution R1 and the pyrogallol aqueous solution R2 are not particularly limited, and may be any amount that allows the gas barrier performance of the test piece S to be appropriately measured, and it is desirable that the total amount of the two when mixed is an amount that does not come into contact with the test piece S. For example, in accordance with JIS K 0301:2016 "Method for analyzing oxygen in exhaust gas," an equal volume of 60 g of potassium hydroxide dissolved in 100 ml of water and an equal volume of 12 g of pyrogallol dissolved in 100 ml of water may be used. In this case, the molar ratio of pyrogallol:alkali (potassium hydroxide) is 1:11.3.

[0043] Next, the test piece S is placed on the upper edge 12t of the opening 12 so as to completely cover the opening 10h of the main body 10.

[0044] Next, the lid 20 is placed over the opening 12 of the main body 10 and then rotated to attach the lid 20 to the opening 12. The test specimen S is then held in a sandwiched state between the top surface 20b of the lid 20 and the upper edge 12t of the opening 12. That is, the storage space 10a of the main body 10 is airtightly isolated from the outside by the test specimen S. Note that the phrase "the storage space 10a of the main body 10 is airtightly isolated from the outside by the test specimen S" used here means that the storage space 10a is airtightly isolated within the range of the gas barrier performance of the test specimen S.

[0045] Next, sealing tape T is wound around the cover portion 20 to connect the cover portion 20 and the main body portion 10. In this manner, the measurement tool 1 is prepared (see FIG. 4(A)).

[0046] Next, the weight (pre-reaction container weight) of the prepared measuring instrument 1 is measured. In this example, the pre-reaction container weight is the total weight of the main body 10 and the cover 20 of the measuring instrument 1, the container 13, the movement prevention member 14, the test piece S, the alkaline aqueous solution R1, the pyrogallol aqueous solution R2, the sealing tape T, and the air in the storage space 10a of the main body 10.

[0047] The instrument used for weight measurement is not particularly limited, and for example, a commercially available electronic balance may be used. If an instrument capable of measuring to a minimum unit of about 0.1 mg is used, more accurate measurements can be achieved.

[0048] Next, as shown in FIG. 4(B), the measuring tool 1 is tilted to tilt the container 13, and the pyrogallol aqueous solution R2 is supplied from the container 13 to the storage space 10a. Then, as shown in FIG. 4(C), the alkaline aqueous solution R1 and the pyrogallol aqueous solution R2 in the storage space 10a are mixed to prepare a mixed solution R3. Even if a measuring tool having a main body 10 configured as shown in FIG. 5(A) and (B) is used instead of the measuring tool 1 shown in FIG. 1 to FIG. 3, the alkaline aqueous solution R1 and the pyrogallol aqueous solution R2 in the storage space 10a can be mixed by tilting the measuring tool to prepare a mixed solution R3. In particular, if one surface of the partition wall 14 is made an inclined surface as shown in FIG. 5(B), the alkaline aqueous solution R1 and the pyrogallol aqueous solution R2 in the storage space 10a can be easily mixed when the measuring tool is tilted.

[0049] Next, the measuring instrument 1 is placed in a thermostatic chamber and left to stand. The temperature in the thermostatic chamber can be appropriately determined within a range of, for example, 10°C to 40°C. The relative humidity in the thermostatic chamber can be appropriately determined within a range of, for example, 0% to 90%. For example, the temperature and relative humidity in the thermostatic chamber may be 23°C and 50%, which are standard conditions for paper testing. The standing time is not particularly limited, but from the viewpoint of measurement accuracy, it is, for example, 4 hours to 24 hours, 6 hours to 24 hours, or 8 hours to 24 hours.

[0050] In the measuring instrument 1 placed in the thermo-hygrostat, the following phenomenon occurs. First, the prepared mixed liquid R3 absorbs oxygen present in the gas phase space in the accommodation space 10a of the main body 10. Since the oxygen concentration in air is 21%, the air pressure in the accommodation space 10a of the main body 10 is 0.21 atm (0.21 kgf / cm) higher than the outside (i.e., inside the thermo-hygrostat). 2) is lowered. When the air pressure inside the storage space 10a is lowered, the external gas (i.e., the gas inside the thermo-hygrostat) passes through the test piece S due to the pressure difference and enters the storage space 10a. Then, the oxygen contained in the gas that has passed through the test piece S is absorbed into the mixed liquid R3, so that the air pressure inside the storage space 10a corresponds to the amount of gas that has passed through the test piece S and the amount of absorbed oxygen. Then, an amount of gas that corresponds to the difference between the air pressure inside the storage space 10a and the external air pressure passes through the test piece S and enters the storage space 10a, and the oxygen in the invaded gas is absorbed into the mixed liquid R3.

[0051] Furthermore, the thermostatic chamber allows air to move between its interior and exterior, and even if gas inside the thermostatic chamber enters the storage space 10a through the test piece S, the air pressure inside the thermostatic chamber is kept constant.

[0052] After a predetermined time has elapsed, the measuring device 1 is removed from the thermo-hygrostat and its weight (post-reaction container weight) is measured. This post-reaction container weight is the total weight of the pre-reaction container weight and the weight of oxygen absorbed by the mixed liquid R3.

[0053] Next, the oxygen permeability of the test piece S is calculated based on the difference between the weight of the container after the reaction and the weight of the container before the reaction. The oxygen permeability of the test piece S is calculated, for example, as the weight oxygen permeability (g / m 2 24hr). Weight oxygen permeability (g / m 2 ·24hr)=(Wa1-Wa0)×(24 / ta)×1 / Sa Wa0: Weight of container before reaction (g) Wa1: Weight of vessel after reaction (g) ta: Standing time (hr) Sa: Area of ​​the opening 10h of the main body 10 (m 2 )

[0054] When the measuring tool 1 is placed in the thermo-hygrostat, some of the water in the mixed liquid R3 may turn into water vapor and evaporate to the outside through the test piece S. Therefore, the evaporation of water vapor may affect the weight difference. Therefore, the gravimetric oxygen transmission rate (g / m 2 ·24hr) may be corrected for water vapor transmission rate.

[0055] The water vapor permeability can be calculated based on measurements made by forming an instrument for measuring water vapor permeability (water vapor permeability measuring instrument) by applying the measuring instrument 1. Specifically, a measuring instrument holding a test piece S is prepared in the same manner as described above, and this is used as the water vapor permeability measuring instrument. However, in the water vapor permeability measuring instrument, only water is contained in the containing space 10a of the main body 10. This water vapor permeability measuring instrument is placed in a constant temperature and humidity chamber together with the measuring instrument 1, and the weights of the container before and after the reaction are measured in the same manner as described above, and the gravimetric water vapor permeability (g / m) is calculated based on the weight difference according to the following formula: 2 24hr). Weight water vapor permeability (g / m 2 ·24hr)=(Wb1-Wb0)×(24 / ta)×1 / Sa Wb0: Weight of the container before reaction of the water vapor transmission rate measuring device (g) Wb1: Weight of the container after reaction of the water vapor transmission rate measuring device (g) ta: Standing time (hr) Sa: Area of ​​the opening 10h of the main body 10 (m 2 )

[0056] Weight water vapor permeability (g / m 2 After obtaining the 24-hour time, measure the weight oxygen permeability (g / m 2 24hr) is corrected as follows: Corrected weight oxygen permeability (g / m 2 24hr) = Uncorrected weight oxygen permeability (g / m 2 24hr) + (-1 × weight water vapor permeability (g / m 2 24 hours) (In the formula, the weight water vapor permeability (g / m 2 If the value of 24hr is negative, the gravimetric water vapor transmission rate (g / m 2 24hr) is set to "0 (zero)".

[0057] The oxygen permeability may be expressed in terms of volume. Specifically, the weight oxygen permeability (g / m 2 Based on the 24hr time, the volumetric oxygen permeability (cc / m 2 24hr). Volumetric oxygen permeability (cc / m 2 24hr) = (corrected weight oxygen permeability (g / m 2 24hr)) / 32×V×1000 (In the formula, R is the gas constant, the volume of an ideal gas at 0°C is 22.4 l / mol, V is the volume of 1 mol of oxygen at the measurement temperature of the ideal gas (23°C), V = R(T + 273) / 273. T is the measurement temperature (23°C). The molecular weight of oxygen is 32 g per mol.) EXAMPLES

[0058] The present invention will be described in detail with reference to examples. However, the present invention is not limited to the following examples. In addition, unless otherwise specified, parts and % indicate parts by mass and % by mass.

[0059] In this experiment, the gas barrier performance of the barrier-coated paper was measured by the following method.

[0060] The experiment was carried out using a measuring device having the configuration shown in FIGS. The measuring device used was a glass bottle (a commercially available jam jar) with a screw-cap lid. This glass bottle was a hollow cylindrical glass bottle (capacity approximately 90 ml) with an opening at the top, and the distance from the inner bottom to the opening was 55.4 mm. The opening of the glass bottle had an outer diameter of 48.8 mm, an inner diameter of 41 mm, and an area of ​​13.2 cm. 2The lid had a top diameter of 56 mm and a communication hole with a diameter of 30 mm was formed in the center of the top surface. In the experiment, the pyrogallol solution was placed in a polyethylene or polypropylene container and placed in a glass bottle with dimensions of 32.7 mm in height, 25 mm in outside diameter, 31.8 mm in distance from the inside bottom to the top, 0.9 mm in sidewall thickness, 23.2 mm in diameter at the opening, and approximately 13.4 ml in capacity. In addition, a glass rod having a length of 50 mm and a diameter of 6 mm was placed in the glass bottle as a movement prevention member. The test specimens used were made by cutting a circle from the barrier-coated paper so as to have a diameter of 53 mm. A rubber sheet packing made of nitrile rubber (NBR) was placed between the test specimen and the top surface of the lid as a leak prevention means. This packing is a ring-shaped member with an outer diameter of 53 mm, an inner diameter of 38 mm, and a thickness of 0.5 mm.

[0061] The pyrogallol aqueous solution used was prepared by dissolving 1.2 g of pyrogallol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., special grade reagent, model number 165-05445) in 10 ml of water. 10.8 ml of this pyrogallol aqueous solution was placed in a container and placed in a glass bottle. The alkaline aqueous solution used was prepared by dissolving 6 g of potassium hydroxide (potassium hydroxide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., special grade reagent, model number 168-21815)) in 10 ml of water. 12 ml of this potassium hydroxide aqueous solution was placed in a glass bottle.

[0062] The weight of the measuring equipment (weight of the container before the reaction and weight of the container after the reaction) was measured using an electronic balance (manufactured by A&D Co., Ltd., model number GR-200, maximum measurement 210 g, minimum unit 0.1 mg).

[0063] In the experiment, the weight of the container before the reaction of the measuring device was measured, then the glass bottle was tilted to prepare a mixture of pyrogallol aqueous solution and potassium hydroxide aqueous solution, the measuring device was placed in a thermo-hygrostat and left to stand for 6 hours, and then the weight of the container after the reaction was measured to calculate the oxygen permeability and water vapor permeability. Note that the water vapor permeability was measured using the measuring device described above with only water in the glass bottle.

[0064] The temperature in the thermo-hygrostat was 23° C. and the relative humidity was 50%. The oxygen concentration in the thermo-hygrostat was kept constant by circulating and supplying indoor air from outside.

[0065] After leaving it to stand for 6 hours, the measuring device was taken out from the thermo-hygrostat, and the weight of the measuring device in this state (post-reaction container weight) was measured using the electronic balance.

[0066] Next, the oxygen permeability and water vapor permeability were calculated based on the post-reaction container weight of the measuring tool taken out of the thermo-hygrostat and the pre-reaction container weight of the measuring tool before the reaction was started. The oxygen permeability and water vapor permeability of the test piece S were calculated by the method described above in the second embodiment.

[0067] In the experiment, the amount of oxygen and water vapor that a mixture of an aqueous solution of pyrogallol and an aqueous solution of potassium hydroxide could absorb in six hours was also measured. That is, with the glass bottle open (i.e., without the lid, test piece, or packing attached), about 10.8 ml of an aqueous solution of pyrogallol was placed in the container and 12 ml of an aqueous solution of potassium hydroxide was placed in the glass bottle, and the two were mixed. To measure the amount of water vapor, 20 ml of water was placed in a separate container and allowed to stand in a constant temperature and humidity chamber (23°C, relative humidity 50%) (sample name: "No sample (open)").

[0068] Next, the oxygen permeability and water vapor permeability of each test piece were measured. In the experiment, barrier coated papers (barrier coated papers A to E) were prepared by coating the surface of the paper substrate with a gas barrier layer, and test pieces (sample names: barrier coated papers A to E) were cut from these barrier coated papers. In addition, heat seal paper (heat seal paper F and G) was prepared by coating the paper substrate with a heat seal agent, and test pieces (sample names: heat seal paper F and G) were cut from these heat seal papers.

[0069] As comparative examples, the oxygen permeability and water vapor permeability were also determined for test pieces (sample names: uncoated paper A and uncoated paper B) cut from the paper base material of the barrier-coated paper.

[0070] The results obtained are shown in Table 1. [Table 1]

[0071] Next, the oxygen permeability and water vapor permeability of the resin sheets (referred to as "films" in Table 2 below) were determined. The composition and other details of each resin sheet (each film) are as shown in the supplementary film explanation column in Table 2 below.

[0072] The results obtained are shown in Table 2. [Table 2]

[0073] From the results shown in Tables 1 and 2, it was confirmed that according to the present invention, it is possible to properly measure the oxygen permeability and water vapor permeability of coated papers based on paper, such as resin sheets, barrier coated papers, and heat seal papers, as well as laminated papers in which these are bonded to resin sheets.

[0074] Next, the relationship between the actual measured oxygen permeability and water vapor permeability values ​​and the calculated oxygen permeability and water vapor permeability values ​​based on a formula was confirmed for the barrier coated papers (barrier coated papers D and E) and heat seal papers (heat seal papers F and G).

[0075] The results are shown in Table 3. Table 3(A) shows the oxygen permeability and water vapor permeability (calculated values) calculated based on the theoretical formula described below (theoretical formula based on the relational equation for the gas permeability coefficient (gas permeability) of the laminated system) when the polyethylene film (LLDPE film) in Table 3(B) is laminated to the barrier coated paper (barrier coated paper D and E in Table 1) and heat seal paper (heat seal paper F and G in Table 1). The oxygen permeability and water vapor permeability (1) in Table 3(A) are values ​​calculated based on the relationship between the actual measured values ​​and film thickness of the LLDPE film in Table 3(B) based on the theoretical formula described below (theoretical formula based on the gas permeability coefficient (gas permeability) relationship formula for the laminated system). The oxygen permeability and water vapor permeability (2) in Table 3(A) are the actual measured values ​​of the oxygen permeability and water vapor permeability of the barrier coated papers D and E and the heat seal papers F and G shown in Table 1.

[0076] Table 3(C) shows the relationship between the actual measured values ​​and the calculated values ​​calculated in Table 3(A) for packaging sheets laminated with the polyethylene film in Table 3(B) (LLDPE film in Table 3(B)) for barrier coated paper (barrier coated paper D and E in Table 3(A)) and heat seal paper (heat seal paper F and G in Table 3(A)). FIG. 6 shows the relationship between the calculated values ​​in Table 3(C) and the actually measured values.

[0077] [Table 3]

[0078] The theoretical formula used to calculate the oxygen permeability and water vapor permeability is as follows. TIFF2025035828000005.tif96150

[0079] From the results shown in Table 3 and Figure 6, it was confirmed that according to the present invention, if measured values ​​of oxygen permeability and water vapor permeability are obtained for a resin sheet alone, a barrier coated paper alone, and a heat seal paper alone, these values ​​can be used to accurately calculate predicted values ​​of oxygen permeability and water vapor permeability of a sheet (laminate sheet) in which a resin sheet and a barrier coated paper are bonded together.

[0080] Next, the gas permeability coefficients (oxygen permeability coefficient and water vapor permeability coefficient) of the barrier coated papers (barrier coated papers A to E) and the heat seal papers (heat seal papers F and G) were determined. The results are shown in Table 4. The oxygen permeability and water vapor permeability in Table 4 are actual measured values, and are the same as the measurement results in Table 1. The oxygen permeability coefficient and water vapor permeability coefficient were calculated based on these values ​​using the following formula. TIFF2025035828000006.tif47150

[0081] [Table 4]

[0082] From the results shown in Table 4, it can be seen that the oxygen permeability can be estimated based on the oxygen permeability coefficient when the thickness of the coating layer is changed. It can also be confirmed that the water vapor permeability can be estimated in a similar manner.

[0083] Next, the gas permeability coefficients (oxygen permeability coefficient and water vapor permeability coefficient) of the resin sheet were determined. The results are shown in Table 5(A). The oxygen permeability and water vapor permeability in Table 5(A) are actual measured values, and are the same as the measurement results in Table 2. The oxygen permeability coefficient and water vapor permeability coefficient were calculated based on these values ​​using the formulas shown in the explanation of Table 4. The oxygen permeability and water vapor permeability of the aluminum thermal deposition layer in Table 5(A) were calculated from the actual measured values ​​of the VMPET film, the actual measured values ​​of the PET film, and values ​​calculated from a theoretical formula based on the film thickness when the thickness of the aluminum vapor deposition layer was 50 nm, as shown in Table 5(B).

[0084] [Table 5]

[0085] From the results shown in Tables 4 and 5, it was confirmed that the gas barrier performance of packaging sheets can be measured based on the oxygen permeability coefficients of resin sheets, barrier coated papers (barrier coated papers A to E) and heat seal papers (heat seal papers F and G), and aluminum vapor deposition layers. Furthermore, from the results shown in Table 5, it was confirmed that the gas barrier performance (i.e., oxygen permeability and water vapor permeability) can be estimated based on the oxygen permeability coefficient and water vapor permeability coefficient when forming multilayer packaging sheets such as packaging sheets made by laminating a resin film onto a resin sheet, barrier coated paper, or heat seal paper, and aluminum-vapor-deposited packaging sheets.

[0086] From the above experimental results, it was confirmed that the gas barrier performance (oxygen permeability and water vapor permeability) of a packaging sheet can be measured by using the measuring device and measuring method of the present invention. Moreover, it was confirmed that the gas barrier performance can be properly measured even for packaging sheets having a paper substrate, which was difficult to measure by the conventional official method. Furthermore, it was confirmed that the measuring device of the present invention does not require the use of a gas delivery mechanism or special precision measuring equipment used in the official method, and therefore the gas barrier performance of a packaging sheet can be measured very easily. [Explanation of symbols]

[0087] 1. Measuring Instruments 10 Main body 10a Storage space 10h Opening of the main body 12 Opening 13 Container 14 Anti-movement parts, partitions 20 Lid 20b Top surface of the lid 20h Lid connection port 30 Leak prevention measures S test piece

Claims

1. An apparatus used to measure the gas barrier performance of a sheet, comprising: a main body having an opening and a hollow space communicating with the outside through the opening; a cover portion that is detachably attached to the opening of the main body portion and that sandwiches and holds a sheet between the opening of the main body portion and a top surface, The lid portion is A communication port is formed on the top surface that connects the front and back. The main body portion is The hollow space includes a first chamber and a second chamber that are separated by a partition wall and communicate with each other in the space above the partition wall. A measuring instrument characterized by:

2. The second chamber is A hollow space in the main body portion, The first chamber is a space within a bottomed cylindrical container having an opening at an upper portion and disposed in the second chamber, The container comprises: The second chamber is sized to be tiltable within the second chamber.

2. The measuring device of claim 1.

3. and a leak prevention means disposed between the lid and the body.

3. A measuring instrument as claimed in claim 1 or 2.

4. A method for measuring the gas barrier performance of a sheet, An alkaline aqueous solution and a pyrogallol aqueous solution are separately contained in a container having an opening and a hollow space communicating with the outside through the opening, a test piece formed of a sheet for measuring gas barrier performance is placed so as to cover an opening of the container, and the test piece is fixed to the container so as not to allow air to enter the container through a gap between the container and the test piece, thereby forming a measuring device; Measure the pre-reaction container weight of this measuring device, After measuring the weight of the container before the reaction, the alkaline aqueous solution and the pyrogallol aqueous solution are mixed in the container of the measuring tool, and then the measuring tool is placed in a constant temperature and humidity chamber and allowed to stand for a predetermined time; After a predetermined time has elapsed, the weight of the container after the reaction of the measuring device is measured, The oxygen permeability of the sheet is calculated based on the difference between the weight of the container after the reaction and the weight of the container before the reaction. A measuring method comprising:

5. a container having an opening and a hollow space communicating with the outside through said opening, is filled with water, a test piece formed of a sheet for measuring gas barrier performance is placed so as to cover the opening of said container, and said test piece is fixed to said container so as not to allow air to enter said container through a gap between said container and said test piece, thereby forming a water vapor transmission rate measuring device; Measure the weight of the container before the reaction of the water vapor transmission rate measuring device, After measuring the weight of the container before the reaction, the water vapor transmission rate measuring device is placed in the same thermo-hygrostat as the measuring device and left for the same period of time as the measuring device; After a predetermined time has elapsed, the weight of the container after the reaction of the water vapor transmission rate measuring device is measured, The water vapor permeability of the sheet is calculated based on the difference between the weight of a container of the water vapor permeability measuring device before the reaction and the weight of the container of the water vapor permeability measuring device after the reaction. The oxygen permeability of the sheet is corrected based on the water vapor permeability of the sheet.

5. The method according to claim 4,

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