JP2021014312A - Multi-piled bag - Google Patents

Abstract

To provide a chemical solution storage container capable of preventing a stored chemical solution from being contaminated, and enabling making-bag processing to be performed efficiently.SOLUTION: A chemical solution storage container 10 includes: an inner bag 11 for storing a chemical solution 3; an outer bag 12 surrounding the inner bag 11; and a spouting member 15 extending by penetrating the inner bag 11 and the outer bag 12. The inner bag 11 includes an outer layer 11D disposed at a side of the outer bag 12. An arithmetic mean roughness Ra of an outer face 11E of the outer layer 11D is 0.08 μm or more.SELECTED DRAWING: Figure 4

Description

The present invention relates to a chemical solution storage container and a chemical solution storage device for storing a chemical solution such as an electrolytic solution for a lithium ion battery.

Conventionally, a chemical solution such as an electrolytic solution for a lithium ion battery is stored in a canister can (metal can), and the metal can containing the chemical solution is conveyed. Then, if necessary, the chemical solution is taken out from the inside of the metal can and used.

The inside of the metal can from which the chemical solution has been taken out is then washed, and the chemical solution is stored and transported again next time.

By the way, the electrolytic solution for lithium batteries needs to be handled carefully, and even when cleaning the metal can once containing the electrolytic solution for lithium batteries, it is necessary to clean it with high precision, and the cleaning cost of the metal can is high. It has become.

For example, regarding cleaning of canister cans, in addition to removing the contents, it is necessary to organize the process so that there is no residue after cleaning (Patent Document 1).

Japanese Unexamined Patent Publication No. 10-436

When a chemical solution such as an electrolytic solution for a lithium battery is stored in a metal can as described above, it is necessary to clean the inside of the metal can every time the chemical solution is taken out, and this cleaning cost is high.

On the other hand, a chemical storage container is arranged in a metal can, a chemical solution nozzle is provided through the metal can and the chemical solution storage container, and the chemical solution storage in the chemical solution storage container is discharged to the outside through the chemical solution nozzle. Equipment has also been developed. Of these, when the chemical solution storage container has a double bag structure, that is, an inner bag and an outer bag, the inner bag containing the chemical solution is protected by the outer bag, and the chemical solution contamination of the metal can can be reliably prevented. .. When producing such a chemical storage container, the inner bag and the outer bag are aligned and heat-sealed with each other.

However, when both the inner bag and the outer bag are made of synthetic resin, the coefficient of friction between the inner bag and the outer bag tends to be high. In this case, there is a problem that the slipperiness between the inner bag and the outer bag is lowered, it becomes difficult to align the inner bag and the outer bag, and the efficiency of the bag making process is lowered.

On the other hand, it is possible to improve the slipperiness between the inner bag and the outer bag by adding the slip agent to the inner bag and the outer bag, but the slip agent elutes into the chemical solution stored in the inner bag. There is a problem that the chemical solution is contaminated by the slip agent.

The present invention has been made in consideration of such a point, and provides a chemical solution storage container and a chemical solution storage device capable of preventing the stored chemical solution from being contaminated and efficiently performing bag making processing. The purpose is.

In the present invention, in a chemical liquid storage container for storing a chemical liquid, an inner bag for storing the chemical liquid, an outer bag surrounding the inner bag, and an injection member extending through the inner bag and the outer bag are provided. Provided is a chemical storage container, wherein the inner bag includes an outer layer arranged on the outer bag side, and the arithmetic mean roughness Ra of the outer surface of the outer layer is 0.08 μm or more. To do.

In the above-mentioned chemical solution storage container, the arithmetic mean roughness Ra of the outer surface of the outer layer may be 0.1 μm or more.

Further, in the above-mentioned chemical solution storage container, the arithmetic mean roughness Ra of the outer surface of the outer layer may be less than 2.50 μm.

Further, in the above-mentioned chemical solution storage container, the haze of the outer layer may be 80% or less.

Further, in the above-mentioned chemical liquid storage container, the outer layer of the inner bag may be formed by mixing two materials having different molecular weights from each other.

Further, in the above-mentioned chemical solution storage container, the outer layer of the inner bag may be formed by mixing low-density polyethylene and high-density polyethylene.

Further, in the above-mentioned chemical storage container, the mass% of the low-density polyethylene may be smaller than the mass% of the high-density polyethylene.

Further, in the above-mentioned chemical solution storage container, the outer bag includes an inner layer arranged on the inner bag side, and the arithmetic average roughness Ra of the inner surface of the inner layer is 0.08 μm or more. You may.

Further, in the above-mentioned chemical solution storage container, the arithmetic mean roughness Ra of the inner surface of the inner layer may be 0.1 μm or more.

Further, in the above-mentioned chemical solution storage container, the arithmetic mean roughness Ra of the inner surface of the inner layer may be less than 2.50 μm.

Further, in the above-mentioned chemical solution storage container, the haze of the inner layer may be 80% or less.

Further, according to the present invention, in a chemical solution storage container for storing a chemical solution, an inner bag for storing the chemical solution, an outer bag surrounding the inner bag, and an inner bag interposed between the inner bag and the outer bag. The inner bag includes an outer layer arranged on the inner bag side, and the outer bag includes an injection member extending through the inner bag, the inner bag, and the outer bag. The arithmetic average roughness Ra of at least one of the outer surface of the outer layer of the inner bag and the inner surface of the inner bag, which includes the inner layer arranged on the inner bag side, is 0.08 μm or more, and Provided is a chemical storage container characterized in that the arithmetic average roughness Ra of at least one of the outer surface of the inner bag and the inner surface of the inner layer of the outer bag is 0.08 μm or more.

Further, the present invention is the chemical solution storage device for storing the chemical solution, which is the above-mentioned chemical solution storage container and the outer can surrounding the chemical solution storage container, and has an upper opening through which the injection member of the chemical solution storage container penetrates. Provided is a chemical storage device characterized by including an outer can.

Further, the present invention includes an inner layer and an outer layer arranged outside the inner layer in the chemical storage bag for storing the chemical solution, and is one of the inner surface of the inner layer and the outer surface of the outer layer. Provided is a chemical storage bag characterized in that the arithmetic mean roughness Ra of at least one of the above is 0.08 μm or more.

As described above, according to the present invention, it is possible to prevent the stored chemical solution from being contaminated and to efficiently perform the bag making process.

FIG. 1 is an enlarged view showing a pouring member of the chemical solution storage device according to the present embodiment. FIG. 2 is a perspective view showing a pouring member of the chemical liquid storage device of FIG. FIG. 3 is an overall schematic view showing the chemical liquid storage device of FIG. FIG. 4 is a side view showing the chemical liquid storage container and the pouring member of FIG. FIG. 5A is a cross-sectional view showing a material for an inner bag, and FIG. 5B is a cross-sectional view showing a material for an outer bag. FIG. 6 is a diagram showing a modified example of the chemical solution storage device according to the present embodiment. 7 (a), (b), and (c) are views showing other modifications of the chemical storage device according to the present embodiment. FIG. 8 is a diagram showing a modified example of FIG. 9 (a) is a cross-sectional view showing the material for the inner bag of FIG. 8, FIG. 9 (b) is a cross-sectional view showing the material for the inner bag of FIG. 8, and FIG. 9 (c) is a cross-sectional view. , FIG. 8 is a cross-sectional view showing a material for an outer bag of FIG. FIG. 10 is a diagram showing the surface roughness and the coefficient of static friction obtained in this embodiment. FIG. 11 is a diagram showing the surface roughness and haze obtained in this example.

(Embodiment of the Invention)
Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 to 5 are views showing an embodiment of a chemical solution storage device for storing a chemical solution according to the present invention.

First, the outline of the chemical solution storage device will be described with reference to FIGS. 1 to 3.

As shown in FIGS. 1 to 3, the chemical solution storage device 1 includes a chemical solution storage container 10 for storing a chemical solution such as an electrolytic solution for a lithium ion battery, and a metal outer can (hereinafter, also referred to as a metal can). It has 2 and. Of these, the chemical storage container 10 is arranged inside the metal can 2, and the metal can 2 surrounds the chemical storage container 10. The outer can 2 can be made of synthetic resin as well as metal.

The chemical solution storage container 10 stores a chemical solution such as a solution for a lithium ion battery. In addition to an electrolytic solution for a lithium ion battery, a chemical solution for removing resist, a chemical solution for etching, or other chemicals used in a semiconductor manufacturing process. It can also store chemicals.

Further, the resist removing chemical solution or etching solution used in the lead frame manufacturing process may be stored in the chemical solution storage container 10, or the resist removing chemical solution or etching solution used in the suspension substrate manufacturing process may be stored. Further, the printing ink used in the printing process may be stored.

Examples of the electrolytic solution for a lithium ion battery stored in the chemical solution storage container 10 include an organic electrolytic solution containing Li ions such as LiClO ₄ and LiPF ₆ .

Such organic electrolytes dislike water, halogens, metal ions and the like. Therefore, as described later, it is preferable to use a material that does not contain water, halogen, metal ions, or the like as much as possible in the inner bag 11 that stores the organic electrolytic solution.

As shown in FIG. 1, the metal can 2 has an upper opening 2a, and the upper opening 2a is sealed by a lid 5. The metal can 2 and the lid 5 are made of stainless steel as a whole.

As shown in FIG. 4, the chemical solution storage container 10 includes an inner bag 11 for storing a chemical solution 3 such as an electrolytic solution for a lithium ion battery, an outer bag 12 surrounding the inner bag 11, and an inner bag 11 and an outer bag 12. It has an injection member 15 extending through the bag. Of these, the dispensing member 15 penetrates the upper opening 2a of the metal can 2. The inner bag 11 corresponds to a chemical storage bag in which the arithmetic mean roughness Ra of the outer surface 11E of the outer layer 11D is 0.1 μm or more, and the outer bag 12 corresponds to the arithmetic mean roughness of the inner surface 12E of the inner layer 12B. It corresponds to a chemical storage bag having Ra of 0.1 μm or more. The term "outer" means the direction from the inner bag 11 to the outer bag 12, and the term "inner" is used to mean the direction from the outer bag 12 to the inner bag 11.

Next, the mounting structure of the dispensing member 15 and the lid 5 will be described with reference to FIGS. 1 to 3.

As shown in FIGS. 1 to 3, the dispensing member 15 is fitted in the upper opening 2a of the metal can 2. The lid 5 is provided so as to cover the pouring member 15 and seals the upper opening 2a of the metal can 2. Further, the lid body 5 is bolted and fixed to the peripheral edge of the upper opening 2a of the metal can 2 by a plurality of bolts 6.

The injection member 15 will be further described. The dispensing member 15 has a peripheral flange 21 at its upper end. By fitting the peripheral flange 21 into the upper opening 2a of the metal can 2, the pouring member 15 is positioned in the upper opening 2a of the metal can 2.

Further, the dispensing member 15 is filled with a chemical liquid nozzle space 15A extending through the inside of the chemical liquid nozzle 16 (described later) and a pressurized gas supplied from the pressurized gas supply nozzle 17 described later. A cylindrical partition wall 20 for partitioning the pressurized gas space 15B is provided. That is, a chemical liquid nozzle space 15A through which the chemical liquid nozzle 16 penetrates is formed inside the cylindrical partition wall 20 of the dispensing member 15, and the outer space of the partition wall 20 in the dispensing member 15 is added. The pressure gas space is 15B.

Further, the dispensing member 15 has a bottom surface 22, and a communication hole 22a is formed in the bottom surface 22. Through the communication hole 22a, the pressurized gas space 15B of the dispensing member 15 and the pressurized space 8 formed between the metal can 2 and the chemical solution storage container 10 communicate with each other.

Further, the dispensing member 15 has a connecting port 26 that continuously extends downward from the partition wall 20. At the lower end of the connecting port 26, a seal fixing portion 25 is formed to which the sealed seal portion 13 formed by integrally sealing the inner bag 11 and the outer bag 12 is fixed. The seal fixing portion 25 of the injection member 15 has a substantially elliptical planar shape, whereby the seal fixing portion 25 and the sealed seal portion 13 of the chemical solution storage container 10 can be easily fixed.

As described above, the chemical solution nozzle 16 penetrates into the chemical solution nozzle space 15A of the dispensing member 15, and the pressurized gas is supplied from the pressurized gas supply nozzle 17 into the pressurized gas space 15B. ..

As shown in FIGS. 1 to 3, the chemical solution nozzle 16 extends in the chemical solution nozzle space 15A of the injection member 15 and is firmly held by the lid 5. The chemical solution nozzle 16 is for pouring out the chemical solution 3 in the chemical solution storage container 10 and discharging it to the outside, but it can also be used for the purpose of filling the chemical solution 3 in the chemical solution storage container 10.

Also, the pressurized gas supply nozzle 17 is firmly held by the lid member 5 is filled from a pressurized gas supply nozzle 17 an inert gas such as N ₂ gas to the pressurized gas space 15B of the pouring member 15 be able to. The inert gas filled in the pressurized gas space 15B from the pressurized gas supply nozzle 17 is then added between the metal can 2 and the chemical storage container 10 from the pressurized gas space 15B through the communication hole 22a. It is sent into the pressure space 8. Then, by supplying the inert gas into the pressurized space 8, the chemical solution storage container 10 can be pressurized from the outside, and the chemical solution 3 in the chemical solution storage container 10 can be discharged to the outside from the chemical solution nozzle 16. ..

Further, the lid 5 is provided with a pressure gauge 18 for detecting the pressure in the pressurized gas space 15B. Furthermore, a connector 16a connected to an external line (not shown) is provided at the tip of the chemical solution nozzle 16 attached to the lid 5, and an external line is provided at the tip of the pressurized gas supply nozzle 17. A connector 17a connected to (not shown) is provided.

The above-mentioned injection member 15 is made of synthetic resin as a whole.

Next, the chemical storage container 10 will be described with reference to FIGS. 4 and 5. The inner bag 11 constituting the chemical solution storage container 10 is obtained by preparing a pair of films made of the material 11A for the inner bag and heat-sealing the peripheral edges of the pair of films to form the heat-sealing portion 11a ( See FIG. 5 (a)).

The inner bag 11 has a laminated structure including an outer layer 11D arranged on the side of the outer bag 12. Of these, the arithmetic mean roughness Ra of the outer surface 11E of the outer layer 11D is 0.1 μm or more. Here, the arithmetic mean roughness Ra is defined by JIS B0601-2001.

In the form shown in FIG. 5A, the inner bag 11 has an inner layer 11B arranged inside, an intermediate layer 11C, and an outer layer 11D arranged outside, and has a three-layer structure. It has become. The intermediate layer 11C is arranged between the inner layer 11B and the outer layer 11D.

The inner layer 11B, the intermediate layer 11C, and the outer layer 11D are all made of synthetic resin, and for example, low-cost and flexible polyolefin materials such as polyethylene (PE) and polypropylene (PP) can be used. .. In particular, it is preferable to use polyolefin to which no slip agent is added for each of the layers 11B, 11C, and 11D.

Since the inner layer 11B is a portion that comes into direct contact with the chemical solution 3, a material that contains as little water, halogen, and metal ions as possible, which is disliked by the electrolytic solution for lithium ion batteries, for example, a material having low water content, low halogen, and low metal ions should be used. Is preferable. As a result, it is possible to prevent the chemical solution 3 stored in the inner bag 11 from being deteriorated or being adversely affected by the inner bag 11.

As the material used for the inner layer 11B, linear low-density polyethylene or low-density polyethylene is preferably used, and it is preferably selected according to the type of the chemical solution 3 stored in the inner bag 11. Further, the material of the inner layer 11B may be formed of a single material, or may be formed by mixing linear low-density polyethylene and low-density polyethylene. In the latter case, the inner layer 11B can be easily formed into a film.

The intermediate layer 11C is preferably formed of linear low density polyethylene (L-LDPE). In this case, the strength of the intermediate layer 11C can be increased. Examples of the materials used for the intermediate layer 11C include UMERIT 125FN and Evolu SP0511 (manufactured by Prime Polymer Co., Ltd.). These materials are preferably used alone. If there is no problem with the strength of the inner bag 11, the intermediate layer 11C can be omitted.

The outer layer 11D contains two materials having different molecular weights from each other, and these materials are mixed and formed. As a result, when the material 11A for the inner bag is produced, the surface roughness of the outer surface 11E of the outer layer 11D can be roughened. That is, the fluidity of the molten material can be reduced during film formation, whereby the material is cooled and solidified with irregularities remaining on the surface of the material. In this way, the arithmetic mean roughness Ra on the outer surface 11E of the outer layer 11D can be set to 0.1 μm or more.

More specifically, the outer layer 11D contains low-density polyethylene (LDPE) and high-density polyethylene (HDPE), and is preferably formed by mixing low-density polyethylene and high-density polyethylene. Examples of the material used for the outer layer 11D include Suntech HD Creolex K4125 (manufactured by Asahi Kasei Chemicals Co., Ltd.) as high-density polyethylene and Sumikasen G201-F (manufactured by Sumitomo Chemical Co., Ltd.) as low-density polyethylene. it can. Further, the mass% of the low density polyethylene is preferably smaller than the mass% of the high density polyethylene.

Further, although the chemical solution 3 is stored in the inner bag 11, the inner bag 11 is not damaged even if pressure is applied from the chemical solution 3 to the inner surface of the inner bag 11 during transportation. The corner portion 11b on the inner surface of 11 has a curved surface.

That is, the chemical solution storage container 10 having the inner bag 11 in which the chemical solution 3 is stored is arranged in the metal can 2 to obtain the chemical solution storage device 1, but when the chemical solution storage device 1 is conveyed, it is contained in the inner bag 11. It is also conceivable that pressure is applied to the inner surface of the inner bag 11 from the stored chemical solution 3.

In such a case, when the corner portion 11b of the inner surface of the inner bag 11 has a polygonal shape, when pressure is applied to the inner surface of the inner bag 11 from the chemical solution 3, a local stress is applied to the corner portion 11b of the polygonal shape. It is also conceivable that the inner bag 11 will be damaged in the vicinity of the corner portion 11b.

On the other hand, according to the present embodiment, since the corner portion 11b of the inner surface of the inner bag 11 is formed of a curved surface, even if pressure is applied to the inner surface of the inner bag 11 from the chemical solution 3 during transportation, the curved surface is used. No local stress is generated in the corner portion 11b, and damage to the inner bag 11 in the vicinity of the corner portion 11b can be prevented.

The corner portion 11b of the inner bag 11 having such a curved surface is obtained by forming the heat-sealed portion 11a so that the corner portion 11b has the curved surface when the inner bag 11 is manufactured.

Next, the outer bag 12 will be described. The outer bag 12 surrounds the inner bag 11 from the outside and is arranged inside the metal can 2, protects the inner bag 11 from the outside, and the impact from the metal can 2 is directly applied to the inner bag 11. It works so that it is not transmitted.

The outer bag 12 has a laminated structure including an inner layer 12B arranged on the side of the inner bag 11. Of these, the arithmetic mean roughness Ra of the inner surface 12E of the inner layer 12B is 0.1 μm or more.

In the form shown in FIG. 5B, the outer bag 12 has an inner layer 12B arranged inside, an intermediate layer 12C, and an outer layer 12D arranged outside, and has a three-layer structure. It has become. The intermediate layer 12C is arranged between the inner layer 12B and the outer layer 12D. The outer layer 12D is arranged on the metal can 2 side when the chemical storage container 10 is arranged in the metal can 2.

The inner layer 12B preferably has a heat-sealing property with respect to the inner bag 11, and is preferably formed of, for example, a polyolefin such as PE or PP. In particular, it is preferable to use polyolefin to which no slip agent is added for the inner layer 12B.

The inner layer 12B contains two materials having different molecular weights from each other, and these materials are mixed and formed. Thereby, the surface roughness of the inner side surface 12E of the inner layer 12B of the outer bag 12 can be roughened in the same manner as the outer layer 11D of the inner bag 11 described above.

More specifically, the inner layer 12B contains low-density polyethylene and high-density polyethylene, and is formed by mixing low-density polyethylene and high-density polyethylene, similarly to the outer layer 11D of the inner bag 11. preferable. Examples of the material used for the inner layer 12B include Suntech HD Creolex K4125 as the high-density polyethylene and Sumikasen G201-F as the low-density polyethylene. Further, the mass% of the low density polyethylene is preferably smaller than the mass% of the high density polyethylene.

The intermediate layer 12C preferably functions as a gas barrier layer, and is preferably formed of, for example, aluminum (Al). As a result, it is possible to prevent the outside atmosphere from entering the chemical solution 3 in the inner bag 11.

The outer layer 12D preferably has impact resistance, and is preferably formed of, for example, polyethylene terephthalate (PET) or stretched nylon (ON).

As described above, the material 12A for the outer bag 12 has excellent impact resistance and gas barrier property as a whole as compared with the material 11A for the inner bag 11, while the material 11A for the inner bag 11 is for the outer bag 12. It is formed of a material having a low water content, a low halogen content, and a low metal ion content as compared with the material 12A of.

By the way, the outer bag 12 is obtained by preparing a front surface film, a back surface film, and a pair of gusset films made of the material 12A for the outer bag 12, and heat-sealing the peripheral edges thereof to form the heat-sealing portion 12a.

In particular, by increasing the area of the heat seal portion 12a at the bottom portion 12e of the outer bag 12, the outer bag 12 can have a gusset-shaped outer shape. The outer bag 12 having such a gusset-shaped outer shape can stand on its own at the bottom portion 12e of the metal can 2.

By making the outer bag 12 having a gusset-shaped outer shape self-supporting in the metal can 2 in this way, the chemical solution storage container 10 can be stably arranged in the metal can 2 as a whole. Therefore, during transportation, the chemical solution storage container 10 does not shake or shift in the metal can 2, and the chemical solution 3 stored in the inner bag 11 can be stably conveyed.

Next, the operation of the present embodiment having such a configuration will be described.

First, a method for manufacturing the chemical storage device 1 will be described.

As shown in FIG. 4, the inner bag 11 is inserted into the outer bag 12 having a gusset-shaped outer shape from the upper opening of the outer bag 12 and arranged. At this time, the inner bag 11 and the outer bag 12 are aligned so as to be heat-sealed in a desired positional relationship.

Next, the injection member 15 is inserted into the inner bag 11 from the upper opening of the inner bag 11.

After that, the upper opening of the inner bag 11 and the upper opening of the outer bag 12 are aligned and heat-sealed integrally. As a result, the upper opening of the inner bag 11 and the upper opening of the outer bag 12 are integrally sealed to form the sealed seal portion 13. At the same time, the seal fixing portion 25 of the dispensing member 15 is also heat-sealed integrally with the inner bag 11 and the outer bag 12, and the dispensing member 15 is fixed to the inner bag 11 and the outer bag 12 by the sealed sealing portion 13 (FIG. 4).

In this way, the chemical solution storage container 10 having the inner bag 11 and the outer bag 12 and to which the injection member 15 is attached can be obtained. On the other hand, a lid 5 to which the chemical solution nozzle 16, the pressurized gas supply nozzle 17, and the pressure gauge 18 are attached is prepared in advance. Next, the chemical solution nozzle 16 is inserted into the chemical solution nozzle space 15A formed by the partition wall 20 of the dispensing member 15, and the chemical solution storage container 10, the lid 5, and the dispensing member 15 are integrally combined. To.

Next, the chemical storage container 10 is inserted into the metal can 2 from the upper opening 2a, and the injection member 15 is fitted into the upper opening 2a of the metal can 2. In this case, the peripheral flange 21 of the dispensing member 15 is fitted into the upper opening 2a of the metal can 2, and the lid 5 is bolted to the peripheral edge of the upper opening 2a of the metal can 2 by a bolt 6 provided on the peripheral edge thereof. To. Further, the pressurized gas supply nozzle 17 attached to the lid 5 is inserted into the pressurized gas space 15B of the injection member 15.

In use, the chemical solution nozzle 16 is connected to an external supply mechanism (not shown) via the connector 16a, and the chemical solution 3 is supplied into the inner bag 11 from this supply mechanism.

Next, the connector 16a of the chemical solution nozzle 16 is sealed by a cap (not shown), and the chemical solution storage device 1 having the chemical solution storage container 10 having the inner bag 11 and the outer bag 12 and the metal can 2 is the destination. Will be transported to. After that, the cap is removed from the connector 16a of the chemical solution nozzle 16 at the transport destination, and the connector 16a of the chemical solution nozzle 16 is connected to the discharge mechanism (not shown).

Next, the connector 17a of the pressurized gas supply nozzle 17 is connected to the N ₂ gas supply mechanism (not shown), and N from the pressurized gas supply nozzle 17 into the pressurized gas space 15B of the pouring member 15. ₂ Gas is supplied. The N ₂ gas in the pressurized gas space 15B is sent from the communication hole 22a of the injection member 15 into the pressurized space 8 between the metal can 2 and the chemical liquid storage container 10, and the chemical liquid storage container 10 is sent from the outside. Pressurize. As a result, the chemical solution 3 stored in the inner bag 11 of the chemical solution storage container 10 can be discharged from the chemical solution nozzle 16 to the discharge mechanism side. During this time, the supply amount of N ₂ gas can be adjusted while observing the pressure of the N ₂ gas as shown in the pressure gauge 18.

As described above, according to the present embodiment, the arithmetic mean roughness Ra of the outer surface 11E of the outer layer 11D of the inner bag 11 is 0.1 μm or more. As a result, the slipperiness between the inner bag 11 and the outer bag 12 can be improved. Therefore, when manufacturing the chemical solution storage container 10, the inner bag 11 and the outer bag 12 can be easily aligned, and the bag making process can be efficiently performed. Further, as described above, by setting the arithmetic average roughness Ra of the outer surface 11E to 0.1 μm or more, it is possible to prevent the formation of wrinkles during the bag making process and greatly improve the bag making processability. it can. Further, according to the present embodiment, the slipperiness between the inner bag 11 and the outer bag 12 can be improved without adding a slip agent to the inner bag 11. Therefore, it is possible to prevent the slip agent from being eluted into the chemical solution 3 stored in the inner bag 11 and contaminating the chemical solution 3.

Further, according to the present embodiment, the outer layer 11D of the inner bag 11 is formed by mixing two materials having different molecular weights from each other. As a result, the fluidity of the molten material can be reduced during film formation, whereby the material can be cooled with irregularities remaining on the surface thereof. Therefore, the surface roughness of the outer surface 11E of the outer layer 11D can be roughened. In particular, when the outer layer 11D is formed by mixing low-density polyethylene and high-density polyethylene, the surface roughness of the outer surface 11E of the outer layer 11D can be roughened and the strength of the inner bag 11 is improved. be able to. Further, when the mass% of the low-density polyethylene is smaller than the mass% of the high-density polyethylene, the impact resistance of the inner bag 11 can be improved.

Further, according to the present embodiment, the arithmetic average roughness Ra of the inner side surface 12E of the inner layer 12B of the outer bag 12 is 0.1 μm or more. As a result, the slipperiness between the inner bag 11 and the outer bag 12 can be further improved, and the bag making process can be performed more efficiently. Further, as described above, by setting the arithmetic average roughness Ra of the inner side surface 12E to 0.1 μm or more, it is possible to prevent the formation of wrinkles during the bag making process and greatly improve the bag making processability. it can. Further, the slipperiness between the inner bag 11 and the outer bag 12 can be further improved without adding a slip agent to the outer bag 12. Therefore, even if the inner bag 11 is unexpectedly damaged and the chemical solution 3 leaks from the inner bag 11, it is possible to prevent the slip agent from being eluted into the chemical solution 3 and contaminating the chemical solution 3.

Further, according to the present embodiment, the inner bag 11 in which the chemical solution 3 is stored is surrounded by the outer bag 12. As a result, the chemical solution storage container 10 can have a double bag structure. Therefore, the inner bag 11 in which the chemical solution 3 is stored is protected by the outer bag 12, and the inner bag 11 can be prevented from being damaged. Further, even if the inner bag 11 is unexpectedly damaged, the chemical solution 3 can be confined in the outer bag 12 and the metal can 2 can be prevented from being contaminated with the chemical solution.

Further, according to the present embodiment, the chemical solution storage device 1 for storing the chemical solution is arranged in the metal can 2 and the metal can 2, and has an inner bag 11 and an outer bag 12 for storing the chemical solution 3. It is equipped with 10. Therefore, as compared with the case where the chemical solution 3 is directly stored in the metal can 2, it is not necessary to clean the metal can 2 frequently, and the expensive cleaning cost can be reduced.

Furthermore, a lid 5 is provided to cover the pouring member 15 and seal the upper opening 2a of the metal can 2, and the lid 5 has a chemical nozzle 16 penetrating the pouring member 15 and a pressurized gas supply. The nozzle 17 is attached in advance. Therefore, the injection member 15 is attached to the chemical solution storage container 10 in advance, the chemical solution nozzle 16 is further passed through the injection member 15, and the lid 5 is fitted and fixed in the upper opening 2a of the metal can 2. The chemical solution nozzle 16 and the pressurized gas supply nozzle 17 can be easily and easily installed.

Although the embodiment of the present invention has been described in detail above, the chemical storage container and the chemical storage device according to the present invention are not limited to the above-described embodiment, and are not deviated from the gist of the present invention. Various changes are possible.

For example, in the above embodiment, an example is shown in which the dispensing member 15 is provided with a cylindrical partition wall 20 for partitioning the inside of the dispensing member 15 into a chemical solution nozzle space 15A and a pressurized gas space 15B. The present invention is not limited to this, and the cylindrical partition wall may be extended from the lower surface of the lid 5 and integrally formed with the lid 5 without providing the cylindrical partition wall 20 on the pouring member 15.

(Modification example 1)
Next, a modified example of the chemical solution storage container according to the present embodiment will be described with reference to FIG.

In the modified example shown in FIG. 6, the outer bag of the chemical solution storage container only has a three-way seal structure, and other configurations are substantially the same as those of the embodiments shown in FIGS. 1 to 5. In the modified example shown in FIG. 6, the same parts as those in the embodiments shown in FIGS. 1 to 5 are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 6, the chemical solution storage container 10 includes an inner bag 11 for storing the chemical solution 3 such as an electrolytic solution for a lithium ion battery, and an outer bag 12 surrounding the inner bag 11. In addition, in FIG. 6, for convenience, the chemical solution storage container 10 from which the injection member 15 has been removed is shown.

The outer bag 12 is obtained by folding a single film made of the material 12A for the outer bag 12 and heat-sealing both side edges to form the heat-sealing portion 12a. That is, the outer bag 12 has a three-way seal structure. It is preferable that the film for the outer bag 12 has a laminated structure as shown in FIG. 5 (b).

Since the outer bag 12 has a three-way seal structure as described above, the number of seal portions can be reduced, and thereby the strength of the outer bag 12 can be improved.

(Modification 2)
Next, with reference to FIG. 7, another modification of the chemical solution storage container according to the present embodiment will be described.

The modified example shown in FIG. 7 is different in that the inner bag and the outer bag of the chemical solution storage container are formed of a cylindrical film, and other configurations are substantially the same as those of the embodiments shown in FIGS. 1 to 5. .. In the modified example shown in FIG. 7, the same parts as those in the embodiments shown in FIGS. 1 to 5 are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 7, the chemical solution storage container 10 has an inner bag 11 for storing the chemical solution 3 such as an electrolytic solution for a lithium ion battery, and an outer bag 12 surrounding the inner bag 11, and the inner bag 11 A dispensing member 15 extending through the outer bag 12 is provided.

Then, the seal fixing portion 25 of the dispensing member 15 is heat-sealed by the sealing sealing portion 13 formed by integrally sealing the inner bag 11 and the outer bag 12, and the dispensing member 15 is the inner bag 11 and the outer bag 12. It is stuck to.

The inner bag 11 and the outer bag 12 are formed by using a cylindrical film having upper openings 11f and 12f and lower openings 11g and 12g, both of which do not include a sealing portion. The cylindrical film for the inner bag 11 has a laminated structure as shown in FIG. 5 (a), and the cylindrical film for the outer bag 12 has a laminated structure as shown in FIG. 5 (b). It is preferable to do so.

In manufacturing the inner bag 11 and the outer bag 12, first, the inner bag 11 made of a cylindrical film is arranged in the outer bag 12 (see FIG. 7A). At this time, the cylindrical film for the inner bag 11 and the cylindrical film for the outer bag 12 are aligned so as to be heat-sealed in a desired positional relationship. Next, the lower openings 11g and 12g of the inner bag 11 and the outer bag 12 are integrally heat-sealed. As a result, the lower openings 11g and 12g of the inner bag 11 and the outer bag 12 are sealed to form the bottom seal portion 14 (see FIG. 7B).

Next, the injection member 15 is inserted into the inner bag 11 from the upper opening 11f of the inner bag 11.

After that, the upper opening 11f of the inner bag 11 and the upper opening 12f of the outer bag 12 are aligned and heat-sealed integrally. As a result, the upper opening 11f of the inner bag 11 and the upper opening 12f of the outer bag 12 are integrally sealed to form the sealed seal portion 13. At the same time, the seal fixing portion 25 of the dispensing member 15 is also heat-sealed integrally with the inner bag 11 and the outer bag 12, and the dispensing member 15 is fixed to the inner bag 11 and the outer bag 12 by the sealed sealing portion 13.

As described above, since the inner bag 11 and the outer bag 12 are both formed of a cylindrical film, the inner bag 11 is inserted into the outer bag 12, and the inner bag 11 and the outer bag 12 are aligned to form a lower opening 11 g. , 12 g and the upper openings 11f and 12f are heat-sealed, so that the chemical liquid storage container 10 can be easily obtained.

Further, in the above-described embodiment, an example in which the arithmetic mean roughness Ra of the inner surface 12E of the inner layer 12B of the outer bag 12 is 0.1 μm or more has been described. However, the arithmetic mean roughness Ra of the inner surface 12E of the inner layer 12B of the outer bag 12 is not limited to this. That is, the arithmetic mean roughness Ra of the inner surface 12E may be less than 0.1 μm. Also in this case, since the arithmetic mean roughness Ra of the outer surface 11E of the outer layer 11D of the inner bag 11 is 0.1 μm or more, the slipperiness between the inner bag 11 and the outer bag 12 is improved. And the bag making process can be performed efficiently. In this case, the material of the inner layer 12B of the outer bag 12 may be formed of a single material such as polyolefin, and may be arbitrary as long as it can have heat-sealing property to the inner bag 11. ..

Further, in the above-described embodiment, an example in which the inner layer 12B of the outer bag 12 uses polyolefin to which a slip agent is not added has been described. However, the present invention is not limited to this, and a material to which a slip agent is added may be used. Even in this case, since the chemical solution 3 is stored in the inner bag 11, it is possible to prevent the slip agent from eluting into the chemical solution 3 and improve the slipperiness between the inner bag 11 and the outer bag 12. ..

Further, in the above-described embodiment, an example has been described in which the outer layer 11D of the inner bag 11 contains two materials having different molecular weights from each other and is formed by mixing these materials. However, the present invention is not limited to this, and if the arithmetic average roughness Ra of the outer surface 11E of the outer layer 11D of the inner bag 11 is 0.1 μm or more, the material forming the outer layer 11D is limited. There is no. The same applies to the inner layer 12B of the outer bag 12.

Further, in the above-described embodiment, an example in which the arithmetic mean roughness Ra of the outer surface 11E of the outer layer 11D of the inner bag 11 is 0.1 μm or more has been described. However, the present invention is not limited to this, and the arithmetic mean roughness Ra of the outer surface 11E of the outer layer 11D may be 0.08 μm or more. That is, if the arithmetic mean roughness Ra of the outer surface 11E of the outer layer 11D is 0.08 μm or more even if it is less than 0.1 μm, the slipperiness between the inner bag 11 and the outer bag 12 is improved. Can be done. Similarly, the arithmetic mean roughness Ra of the inner surface 12E of the inner layer 12B of the outer bag 12 is not limited to 0.1 μm or more, and may be 0.08 μm or more.

Further, in the above-described embodiment, the arithmetic mean roughness Ra of the outer surface 11E of the outer layer 11D of the inner bag 11 is preferably less than 2.50 μm. As a result, it is possible to suppress a decrease in the transparency of the outer layer 11D due to an increase in the arithmetic mean roughness Ra of the outer surface 11E. That is, when the transparency of the outer layer 11D is lowered, it may be difficult to visually recognize whether or not the chemical solution is stored in the inner bag 11, and there is a problem that the handleability of the operator may be lowered. Occurs. In addition, this may cause the operator to accidentally spill the chemical solution, and in this case, if the chemical solution is harmful, it may cause a safety problem.

However, as described above, by setting the arithmetic mean roughness Ra of the outer surface 11E of the outer layer 11D to less than 2.50 μm, it is possible to suppress a decrease in the transparency of the outer layer 11D. Therefore, it is possible to visually recognize whether or not the chemical solution is stored in the inner bag 11, and it is possible to improve the handleability of the operator and ensure safety.

From this, the haze of the outer layer 11D of the inner bag 11 is preferably 80% or less. Here, the haze is defined by JIS K7136. The inner layer 11B and the intermediate layer 11C of the inner bag 11 are preferably formed and laminated using a synthetic resin material that can ensure visibility, and are generally used. From this, the transparency of the film forming the inner bag 11 can be relatively greatly affected by the haze of the outer layer 11D. Therefore, as described above, by setting the haze of the outer layer 11D to 80% or less, it is possible to suppress a decrease in the transparency of the film of the inner bag 11, improving the handleability of the operator and improving safety. Can be secured.

In order to suppress the decrease in transparency of the outer bag 12, the intermediate layer 12C of the outer bag 12 is preferably formed of aluminum oxide or silicon oxide, and is low in ethylene vinyl alcohol or polyamide. It may be formed of a resin layer having gas permeability. In this case, the intermediate layer 12C can function as a gas barrier layer and can ensure the transparency of the chemical solution in the inner bag 11 so that it can be visually recognized.

In the outer bag 12, as in the inner bag 11, the arithmetic mean roughness Ra of the inner surface 12E of the inner layer 12B is preferably less than 2.50 μm, and the haze of the inner layer 12B is It is preferably 80% or less.

Further, in the above-described embodiment, an example in which the chemical solution storage container 10 includes an inner bag 11 and an outer bag 12 has been described. However, it is not limited to this. For example, as shown in FIGS. 8 and 9, the chemical storage container 10 may have a triple bag structure.

That is, the chemical storage container 10 shown in FIGS. 8 and 9 includes an inner bag 11, an outer bag 12, and an inner bag 30 interposed between the inner bag 11 and the outer bag 12. The inner bag 30 is obtained by preparing a pair of films made of the material 30A for the inner bag and heat-sealing the peripheral edges of the pair of films to form the heat-sealing portion 30a. Here, as shown in FIG. 9B, the inner bag 30 shows an example in which the inner bag 30 is composed of a single layer film. The dispensing member 15 extends through the inner bag 11, the inner bag 30, and the outer bag 12.

In the embodiment shown in FIGS. 8 and 9, at least one of the outer surface 11E of the outer layer 11D of the inner bag 11 and the inner surface 30B (the surface on the side of the inner bag 11) of the inner bag 30 has an arithmetic mean roughness Ra. , 0.08 μm or more. Further, the arithmetic average roughness Ra of at least one of the outer surface 30C (the surface on the outer bag 12 side) of the inner bag 30 and the inner surface 12E of the inner layer 12B of the outer bag 12 is 0.08 μm or more. There is.

Here, when the arithmetic mean roughness Ra of the inner surface 30B of the inner bag 30 is 0.08 μm or more, or when the arithmetic mean roughness Ra of the outer surface 30C of the inner bag 30 is 0.08 μm or more, the middle bag 30 is medium. The bag 30 can be formed of the same material as the outer layer 11D of the inner bag 11 (or the inner layer 12B of the outer bag 12). When the inner bag 30 has a laminated structure, for example, an inner layer (not shown) arranged on the inner bag 11 side and an outer layer (not shown) arranged on the outer bag 12 side are shown. The inner layer and the outer layer of the inner bag 30 can be formed of the same material as the outer layer 11D of the inner bag 11 (or the inner layer 12B of the outer bag 12, respectively). In this case, another layer may be formed between the inner layer and the outer layer of the inner bag 30.

According to the chemical storage container 10 as shown in FIG. 8, the slipperiness between the inner bag 11 and the inner bag 30 can be improved, and the slipperiness between the inner bag 30 and the outer bag 12 is improved. The inner bag 11, the inner bag 30, and the outer bag 12 can be easily aligned, and the bag making process can be efficiently performed. In particular, by setting the arithmetic mean roughness Ra of both the outer surface 11E of the inner bag 11 and the inner surface 30B of the inner bag 30 to 0.08 μm or more, the slipperiness between the inner bag 11 and the inner bag 30 is further improved. It can be further improved. Similarly, by setting the arithmetic mean roughness Ra of both the outer surface 30C of the inner bag 30 and the inner surface 12E of the outer bag 12 to 0.08 μm or more, the slipperiness between the inner bag 30 and the outer bag 12 is increased. It can be further improved. The chemical storage container 10 is not limited to having a triple bag structure as shown in FIGS. 8 and 9, and has an arithmetic average roughness Ra of at least one of the surfaces of the adjacent bags. If it is 0.08 μm or more, the number of bags is not limited, such as a quadruple bag structure.

Based on the above-described embodiment, an inner bag 11 as a chemical storage bag was prepared, and the arithmetic mean roughness Ra of the outer surface 11E of the outer layer 11D of the inner bag 11 was measured. Here, a single-layer film corresponding to the outer layer 11D of the inner bag 11 was formed, and the arithmetic mean roughness Ra was measured.

(Example 1)
The outer layer 11D of the inner bag 11 was formed by mixing 20% by mass of low density polyethylene and 80% by mass of high density polyethylene. Specifically, the outer layer 11D of the inner bag 11 is made of inflation by mixing 20% by mass of Sumikasen G201-F (low density polyethylene) and 80% by mass of Suntech HD Creolex K4125 (high density polyethylene). Obtained by filming. Inflation film formation was performed by setting the die diameter to 1060 mm, the feed rate to 18 m / min, and the film formation temperature to 170 to 175 ° C.

The arithmetic mean roughness Ra of the outer surface 11E of the outer layer 11D of the inner bag 11 obtained as described above was measured. The results are shown in Table 1 and FIG. A non-contact surface shape measuring instrument (New View 6300, manufactured by Zygo Co., Ltd.) was used to measure the arithmetic mean roughness Ra.

As shown in Table 1 and FIG. 10, the outer layer 11D of the inner bag 11 is formed by mixing 20% by mass of Sumikasen G201-F and 80% by mass of Suntech HD Creolex K4125 to form an arithmetic mean roughness. It was confirmed that Ra was increased to 0.1 μm or more.

Further, the coefficient of static friction μs on the outer surface of the inner bag 11 was measured and shown in Table 1 and FIG. A friction measuring instrument (TR-2, manufactured by Toyo Seiki Co., Ltd.) was used for measuring the static friction coefficient. The coefficient of static friction was measured by rubbing the film to be measured against a stainless steel reference plate. Further, in FIG. 10, the coordinates indicating the static friction coefficient are logarithmic coordinates.

As shown in Table 1 and FIG. 10, the outer layer 11D of the inner bag 11 is formed by mixing 20% by mass of Sumikasen G201-F and 80% by mass of Suntech HD Creolex K4125 to form a static friction coefficient μs. It was confirmed that the value was reduced to 0.20 or less.

Here, the threshold value of the static friction coefficient μs is even more preferably 0.20, but the present inventor has found that even if it is 0.40, it has sufficient slipperiness.

In general, the coefficient of static friction can be expressed by the friction angle (the minimum angle at which an object placed on a slope slides out due to its own weight). For example, as in Comparative Example 2 shown in Table 1 described later, when the static friction coefficient is 5.00, the friction angle is about 80 °. In this case, the object starts to slide due to its own weight unless the slope is tilted to 80 °. There is no such thing. Further, for example, when the coefficient of static friction is 1.00, the friction angle is 45 °, and in this case, the object can slide out by tilting the slope to 45 °. On the other hand, when the coefficient of static friction is 0.40, the friction angle is about 22 °. In this case, the more the object starts to slip, the more slippery it becomes just by setting the angle of the slope to 22 °.

If the surface is slippery and has a coefficient of static friction or less corresponding to a friction angle of 22 °, scratches or wrinkles may be formed on the film in the alignment process between the inner bag 11 and the outer bag 12 in the bag making process. The present inventor has found that it is possible to prevent the film from being damaged and to efficiently align the inner bag 11 and the outer bag 12. Therefore, by setting the threshold value of the static friction coefficient to 0.40, the outer layer 11D capable of aligning the inner bag 11 and the outer bag 12 without any inconvenience can be selected. And, as a matter of course, the outer layer 11D according to the first embodiment can satisfy the threshold value of the static friction coefficient. Further, by setting the threshold value of the static friction coefficient to 0.40, the threshold value of the arithmetic mean roughness Ra can be set to 0.08 μm.

In addition, the haze of the outer layer 11D of the inner bag 11 formed as described above was measured and shown in Table 1 and FIG. As shown in Table 1 and FIG. 11, the haze of the outer layer 11D was 80% or less. A haze meter (HM-150, manufactured by Murakami Color Technology Research Institute) was used for the haze measurement. Further, the transparency was visually confirmed, and it was confirmed that the outer layer 11D had a transparency enough to visually recognize the chemical solution in the inner bag 11.

(Example 2)
Further, as Example 2, for SPUM-SL (manufactured by DNP Technopack Co., Ltd.), the arithmetic average roughness Ra, the static friction coefficient μs, and the haze of the outer surface were measured in the same manner as in Example 1, and Table 1 and FIGS. 10 and FIG. 11 show. Unlike Example 1, SPUM-SL is formed of a single material.

As shown in Table 1 and FIG. 10, in the outer layer 11D in Example 2, it was confirmed that the arithmetic mean roughness Ra was 0.08 μm or more and the threshold value could be satisfied. It was also confirmed that the arithmetic mean roughness Ra was less than 2.50 μm. Further, it was confirmed that the static friction coefficient μs was set to 0.40 or less and the threshold value could be satisfied. Further, as shown in Table 1 and FIG. 11, it was visually confirmed that the haze was 80% or less and the chemical solution had a visible transparency.

(Example 3)
Further, as Example 3, for UBE polyethylene B128 (manufactured by Ube-Maruzen Polyethylene Co., Ltd.), the arithmetic mean roughness Ra, the static friction coefficient μs, and the haze of the outer surface were measured in the same manner as in Example 1, respectively. 10 and FIG. 11 are shown. Unlike Example 1, UBE polyethylene B128 is formed of a single material.

As shown in Table 1 and FIG. 10, in the outer layer 11D in Example 3, it was confirmed that the arithmetic mean roughness Ra was 0.08 μm or more and the threshold value could be satisfied. It was also confirmed that the arithmetic mean roughness Ra was less than 2.50 μm. Further, it was confirmed that the static friction coefficient μs was set to 0.40 or less and the threshold value could be satisfied. Further, as shown in Table 1 and FIG. 11, it was visually confirmed that the haze was 80% or less and the chemical solution had a visible transparency.

(Comparison example)
In Table 1 and FIG. 10, as Comparative Example 1, the arithmetic mean roughness Ra when the outer layer 11D was formed of kernel KF273 (linear low-density polyethylene, manufactured by Japan Polyethylene Corporation) and Comparative Example 2 , Evolu SP0511 (Linear low-density polyethylene, manufactured by Prime Polymer Co., Ltd.) was used to measure the arithmetic mean roughness Ra. Further, as Comparative Example 3, the arithmetic mean roughness Ra when the outer layer 11D was formed of Novatec LC602A (manufactured by Japan Polyethylene Corporation) was shown. Further, Table 1, FIG. 10 and FIG. 11 show the static friction coefficient and haze of Comparative Examples 1 to 3. The arithmetic mean roughness Ra, the coefficient of static friction, and the haze were measured in the same manner as in Example 1. In Comparative Example 3, the arithmetic mean roughness Ra was 2700 nm and the haze was 88.2%. Then, it was visually confirmed that the chemical solution was difficult to see. Therefore, Novatec LC602A is treated as Comparative Example 3 in that it is difficult to visually recognize the chemical solution.

1 Chemical storage device 2 Metal can 2a Upper opening 3 Chemical liquid 5 Lid 6 Bolt 8 Pressurized space 10 Chemical storage container 11 Inner bag 11A Material 11B Inner layer 11C Intermediate layer 11D Outer layer 11E Outer side surface 11a Heat seal part 11b Corner 12 Outer bag 12A Material 12B Inner layer 12C Intermediate layer 12D Outer layer 12E Inner side surface 12a Heat seal part 13 Sealed seal part 15 Injection member 15A Chemical solution nozzle space 15B Pressurized gas space 16 Chemical solution nozzle 17 Pressurized gas supply nozzle 20 Cylindrical partition wall 22 Bottom surface 22a Communication hole 25 Seal fixing part 26 Connection port 30 Inner bag 30A Material 30B Inner side surface 30C Outer side surface 30a Heat seal part

Claims (1)

In the chemical storage container for chemical storage
An inner bag for storing chemicals and
The outer bag that surrounds the inner bag and
A dispensing member extending through the inner bag and the outer bag is provided.
The inner bag includes an outer layer arranged on the outer bag side.
A chemical storage container characterized in that the arithmetic average roughness Ra of the outer surface of the outer layer is 0.08 μm or more.

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