Packaging body

Abstract

The purpose of the present invention is to provide a packaging body including: a container capable of, even if a borazine compound is repeatedly stored therein, safely storing or transporting the borazine compound without deteriorating the borazine compound; and the borazine compound. The packaging body comprises a liquid, a sealed container in which the liquid is stored, and a gas which is filled in a space in the sealed container, the packaging body being characterized in that the liquid contains a borazine compound, the gas is an inert gas, the sealed container has pressure resistance of 0.1 MPa or more and light-shielding properties, the sealed container has a liquid storage part, and the surface roughness (Ra) of an inner surface of the liquid storage part is 1.0 μm or less.

Description

Packaging

[0001] The present invention relates to a package comprising a liquid to be stored or transported, a sealed container for storing the liquid, and a gas filled in the space within the sealed container, and in particular to a package comprising a liquid containing a borazine compound.

[0002] As semiconductor devices become faster and more highly integrated, there is a demand for lowering the dielectric constant of interlayer insulating films to prevent signal delays. For example, Patent Documents 1 and 2 propose borazine compounds having a borazine skeleton in the molecule as materials exhibiting low dielectric constants.

[0003] Conventionally, borazine compounds have been synthesized in small amounts at the laboratory level and typically stored in reagent bottles, but considering future mass production, it will be necessary to transport or store them in larger containers. However, particularly in semiconductor materials, high purity is required from the standpoint of film formation stability and electrical properties, and it is important that the purity of the borazine compound does not decrease even after transportation or storage. Patent Document 3 discloses a method for cleaning a container for storing a borazine compound, as a technique for solving this problem, and is characterized by a step of cleaning the container for storing a borazine compound with pure water and then drying it until the dew point of the nitrogen gas when flowed with nitrogen gas is −30° C. or lower.

[0004] JP 2000-340689 A JP 2003-119289 A JP 2008-110940 A

[0005] Containers for transporting or storing borazine compounds may be reused after cleaning, etc., but solid residues such as polymers of the borazine compound and decomposition products due to trace oxygen may adhere to the inner surface of a container that has once contained a borazine compound. Once these solid residues have adhered to the inside of the container, they are difficult to completely remove by cleaning with ordinary solvents, etc., and repeated use of the container has tended to increase the amount of solid residues adhering to the inner surface.

[0006] The inventors have conducted studies and found that even a small amount of this solid residue may promote polymerization or decomposition of the borazine compound when the borazine compound is stored in the container again, and that with each repeated use, the purity of the stored borazine compound decreases, resulting in the problem that the borazine compound cannot be safely transported or stored.

[0007] Therefore, an object of the present invention is to provide a package including a container and a borazine compound, which can safely store or transport a borazine compound without causing deterioration of the borazine compound even when the borazine compound is repeatedly stored therein.

[0008] The present invention achieves the above-mentioned object as follows: [1] A package comprising a liquid, a sealed container for storing the liquid, and a gas filling the space within the sealed container, wherein the liquid contains a borazine compound, the gas is an inert gas, the sealed container has a pressure resistance of 0.1 MPa or more and light-shielding properties, the sealed container has a liquid storage section, and the surface roughness (Ra) of the inner surface of the liquid storage section is 1.0 μm or less. [2] The package according to [1], wherein the sealed container comprises a container body having the liquid storage section and at least two valves. [3] The package according to [2], wherein, of the two valves, a first valve injects an inert gas into the container body, and a second valve discharges the liquid in liquid or gas form from the container body to the outside. [4] The package according to [3], wherein both the first valve and the second valve are diaphragm valves. [5] The package according to any one of [1] to [4], wherein the liquid storage section has an inner surface that has a surface roughness (Ra) of 1.0 μm or less and is electropolished. [6] The package according to any one of [1] to [5], wherein the liquid contains a borazine compound with a purity of 99% or more. [7] The package according to any one of [1] to [6], wherein the borazine compound is represented by the structural formula (I). [In formula (I), R １1 , R １2 , R １３ , R ２１ , R ２２ and R ２３may be the same or different and are hydrogen atoms or alkyl groups.] [8] The package according to any one of [1] to [7], wherein the gas filling the space within the sealed container is an inert gas including nitrogen gas or argon gas. [9] The package according to any one of [1] to [8], wherein the dew point of the gas filling the space within the sealed container is -70°C or lower.

[10] The package according to any one of [3] to [9], wherein the sealed container further includes an injection pipe extending from the first valve and a discharge pipe extending from the second valve, wherein the inert gas injected by the first valve is guided to the end of the injection pipe, and the liquid or gas discharged by the second valve is guided from the end of the discharge pipe.

[11] The package according to any one of [2] to

[10] , wherein the container body has the liquid storage section located at the lower side and a lid located at the upper side, wherein all of the at least two valves are attached to the lid, and the liquid storage section and the lid are pressure-welded via a packing.

[0009] According to the present invention, even when a container for storing a borazine compound is used repeatedly, the borazine compound can be safely stored or transported without deterioration.

[0010] It is a figure which shows the appearance of one embodiment of the package body based on this invention. It is a top view of Figure 1. It is a cross-sectional view of AA of Figure 1. It is a cross-sectional view of one embodiment of the first valve part based on this invention. It is a cross-sectional view of one embodiment of the second valve part based on this invention.

[0011] The present invention provides a package comprising a liquid, a sealed container for storing the liquid, and a gas filling the space within the sealed container, wherein the liquid contains a borazine compound, the gas is an inert gas, the sealed container has a pressure resistance of 0.1 MPa or more and light-shielding properties, the sealed container has a liquid storage section, and the surface roughness (Ra) of the inner surface of the liquid storage section is 1.0 μm or less. According to the package of the present invention, it is possible to prevent solid residues such as polymers of the borazine compound and decomposition products due to trace oxygen from adhering to the inner surface of the liquid storage section, and even if the sealed container is used repeatedly, the liquid containing the borazine compound to be stored or transported will not deteriorate.

[0012] In the present invention, the borazine compound is borazine (B ３ H ６ N ３ ) or a compound in which at least one hydrogen atom bonded to the boron atom or nitrogen atom of borazine is substituted with an organic group.

[0013] The borazine compound is preferably represented by the structural formula (I).

[0014]

[0015] [In formula (I), R １1 , R １2 , R １３ , R ２１ , R ２２ and R ２３ may be the same or different and are a hydrogen atom or an alkyl group.

[0016] The alkyl group is preferably an alkyl group having 1 to 4 carbon atoms, and is preferably a methyl group or an ethyl group.

[0017] In formula (I), R １1 , R １2 , R １３ , R ２１ , R ２２ and R ２３ Preferably, at least one of R is not a hydrogen atom, ２１ , R ２２ and R ２３ is a hydrogen atom, and R １1 , R １2 and R １３ More preferably, R is an alkyl group. ２１ , R ２２ and R ２３ is a hydrogen atom, R １1 , R １2 and R １３ is more preferably an alkyl group having 1 to 4 carbon atoms, further preferably a methyl group or an ethyl group, and most preferably a methyl group (i.e., the borazine compound represented by formula (I) is N,N',N''-trimethylborazine).

[0018] The route of obtaining the borazine compound is not particularly limited. For example, when the borazine compound is commercially available, the purchased borazine compound may be stored in a sealed container, or a borazine compound prepared by oneself may be stored. As a method for preparing the borazine compound, a known method may be adopted, and the borazine compound may be prepared by referring to the description in paragraphs

[0027] to

[0034] of Patent Document 3 mentioned above.

[0019] The liquid containing the borazine compound is usually the borazine compound itself, but it may also contain components other than the borazine compound, such as a solvent, and may also contain the solvent (reaction solvent) used in synthesizing the borazine compound. The borazine compound content in the liquid containing the borazine compound is preferably 95% by volume or more, more preferably 98% by volume or more, and most preferably 100% by volume. That is, the borazine compound content in the liquid containing the borazine compound is preferably 95 to 100% by volume, more preferably 98 to 100% by volume. Examples of the solvent include ether-based solvents such as tetrahydrofuran, monoethylene glycol dimethyl ether (monoglyme), diethylene glycol dimethyl ether (diglyme), triethylene glycol dimethyl ether (triglyme), and tetraethylene glycol dimethyl ether (tetraglyme); hydrocarbon-based solvents such as hexane, toluene, heptane, benzene, and xylene; and chlorine-containing solvents such as dichloromethane, chloroform, and carbon tetrachloride.

[0020] The inert gas is a gas that does not react with the borazine compound, and in addition to nitrogen gas, rare gases such as helium gas, neon gas, argon gas, krypton gas, and xenon gas can be used. Nitrogen gas or argon gas is preferred, and nitrogen gas is particularly preferred.

[0021] Since the borazine compound may be hydrolyzed by water, the dew point of the gas filled in the space inside the sealed container, i.e., the inert gas, is preferably −30° C. or lower, more preferably −40° C. or lower, even more preferably −50° C. or lower, and particularly preferably −70° C. or lower, and although the lower limit is not particularly limited, it may be −80° C. That is, the dew point of the inert gas is preferably −80 to −30° C., more preferably −80 to −40° C., even more preferably −80 to −50° C., and particularly preferably −80 to −70° C.

[0022] Below, we will explain the packaging body according to the embodiment with reference to the figures, but the present invention is not limited to the embodiment below, and it is of course possible to implement it by making appropriate modifications within the scope that is consistent with the purpose described above and below.

[0023] Fig. 1 is a diagram showing the appearance of a package 1 according to the present invention. As shown in Fig. 1, the package 1 includes a liquid 10 containing a borazine compound, a sealed container 20 for storing the liquid 10, and an inert gas 30 filled in the space of the sealed container 20.

[0024] The sealed container 20 preferably has a container body and at least two valves. Of the two valves, a first valve is for injecting an inert gas into the container body, and a second valve is for introducing an inert gas into the container body or for discharging the liquid in a liquid or gaseous state from inside the container body to the outside by heating the container body from the outside, for example.

[0025] <Explanation of the sealed container 20> Fig. 2 is a top view of the package 1. In Fig. 2, the top plate of the cover has been removed so that the inside can be seen.

[0026] FIG. 3 is a cross-sectional view taken along line AA in FIG.

[0027] 2 and 3, the sealed container 20 is a sealed container that contains a liquid containing a borazine compound, and has a liquid storage section 110, a container body 100, a first valve section 200, and a second valve section 300. In Fig. 3, the container body 100 is cut substantially from the center, and the conduit sections of the first valve section 200 and the second valve section 300 are cut substantially from the center.

[0028] The container body 100 is the remaining part of the sealed container 20 excluding the first valve part 200 and the second valve part 300 .

[0029] The first valve section 200 is an inert gas injection unit used when injecting the inert gas 30 into the container body 100, and is provided with a valve dedicated to the inert gas.

[0030] The second valve section 300 is a unit for discharging the liquid 10 used when discharging the liquid 10 in liquid or gas form from inside the container body 100 to the outside, and is provided with a valve dedicated to the liquid 10 .

[0031] The sealed container 20 has pressure resistance. Specifically, the sealed container 20 preferably has a pressure resistance of 0.1 MPa or more. The pressure resistance of the container may be measured by a method conforming to JIS standards, and is preferably measured by a water pressure test such as JIS B8265 or JIS B8266.

[0032] The pressure resistance (pressure resistance) of the sealed container 20 is preferably 0.1 MPa or more, and more preferably 0.2 MPa or more. On the other hand, the upper limit of the pressure resistance of the container is not particularly limited, but from the viewpoint of ease of handling of the container, it is preferably 5.0 MPa or less, and more preferably 2.0 MPa or less. That is, the pressure resistance of the sealed container 20 is preferably 0.1 to 5.0 MPa, and more preferably 0.2 to 2.0 MPa.

[0033] The sealed container 20 is not only airtight and pressure-resistant, but also light-shielding, and is therefore formed from a light-shielding material. Light-shielding means that the light transmittance is substantially zero. In this embodiment, the entire container body 100 and at least the portions of the first valve section 200 and the second valve section 300 that affect the light-shielding properties are made of stainless steel, thereby achieving high light-shielding properties. The light-shielding material is not particularly limited, and in addition to stainless steel, metal materials such as corrosion-resistant alloys (e.g., Hastelloy (registered trademark), the MAT series and MA series manufactured by MMC Superalloy Corporation, etc.) can also be used.

[0034] In the package of the present invention, the sealed container 20 has a liquid storage section 110, and the surface roughness (Ra) of the inner surface of the liquid storage section 110 is 1.0 μm or less, preferably 0.8 μm or less, and more preferably 0.5 μm or less, with the lower limit being, for example, 0.01 μm or 0.05 μm. That is, the surface roughness (Ra) of the inner surface of the liquid storage section 110 is preferably 0.01 to 1.0 μm, more preferably 0.05 to 0.8 μm, and even more preferably 0.05 to 0.5 μm. This reduces the unevenness of the inner surface of the liquid storage section, making it possible to suppress adhesion of solid residues to the inner surface of the container, and even if they do adhere, they can be easily and reliably removed by ordinary cleaning, resulting in the borazine compound being able to be stored stably without deterioration.

[0035] The "surface roughness (Ra)" referred to in the present invention means the arithmetic mean roughness defined in JIS B0601 ('01).

[0036] The inner surface of the liquid storage section, the surface roughness of which is adjusted to the above range, is preferably subjected to electrolytic polishing. By performing electrolytic polishing, the surface roughness (Ra) of the inner surface of the container can be easily controlled to the above range. The electrolytic polishing method is not particularly limited, and for example, a known electrolytic polishing treatment method may be used, and the treatment conditions may be appropriately set so as to achieve the desired surface roughness (Ra).

[0037] The liquid containing the borazine compound preferably fills 40 to 80% by volume of the total volume of the liquid storage section of the sealed container. The volume of the liquid storage section is, for example, about 1 to 10 L.

[0038] Furthermore, the sealed container 20 is required to have at least two valves, one dedicated to the inert gas and one dedicated to the liquid containing the borazine compound, as a minimum. However, other valves may be added to increase the number of valves to more than two. For example, increasing the number of valves to more than two allows valves of different diameters or shapes to be used depending on the application, or the number of valves to be used to change depending on the amount of use. Furthermore, the connection portions of the valve dedicated to the inert gas and the valve dedicated to the liquid 10 may be of different, incompatible shapes to prevent incorrect connection. Furthermore, a check valve may be added to the first valve unit 200 to prevent leakage of the inert gas 30 or the liquid 10 from inside the container body 100 to the outside. Furthermore, a check valve may be added to the second valve unit 300 to prevent backflow of the liquid 10 or to prevent outside air from entering the container body 100 from the outside.

[0039] Furthermore, in addition to the two or more valves, the sealed container 20 may have one or more ports (not shown) opened in the container body 100. This port can be used to easily fill the container with liquid or clean the container. The diameter of the port is not particularly limited, but is preferably 5 mm or larger in terms of ease of handling during filling and cleaning. The port may also be designed to maintain its airtightness with a cap. The cap is not particularly limited, but it is preferable that it has a screw-type closure to ensure pressure resistance and airtightness.

[0040] <Detailed Description of Container Body 100> Next, one embodiment of the container body 100 will be shown. As shown in Fig. 3, the container body 100 has a cup-shaped liquid storage section 110 that substantially holds the liquid 10, and a lid section 120 that is in pressure contact with the liquid storage section 110 via a packing. In the container body 100, the liquid storage section 110 is located on the lower side, and the lid section 120 is located on the upper side. Here, a first valve section 200 and a second valve section 300 are attached to the lid section 120. Note that if more than two valves are used, all of the valves are attached to the lid section 120.

[0041] In one embodiment of the container body 100, the liquid storage portion 110 and the lid portion 120 are pressure-welded via a gasket, and are pressure-welded via a rounded top gasket 122. The liquid storage portion 110 and the lid portion 120 may be integrated into one body like a seamless container without a flange. Alternatively, a glove box (not shown) may be filled with an inert gas, and the liquid storage portion 110 and the lid portion 120 may be separated within the glove box to fill the liquid storage portion 110 with liquid or to drain the liquid from the liquid storage portion 110.

[0042] The liquid storage section 110 preferably comprises an upper head plate 111 located on the side, a lower head plate 112 located at the bottom, a skirt portion 113 that serves as a foot for supporting the liquid storage section 110, a neck portion 114 that forms the upper opening, and a ring flange 115 that is a ring-shaped plate having a joint surface with the lid portion 120; however, the neck portion 114 may not be included. The liquid storage section 110 can be formed by casting or molding, or by welding or bonding separately manufactured parts. For example, the upper head plate 111 and the lower head plate 112 can be integrally formed by drawing, the skirt portion 113 and the neck portion 114 can be formed by welding one short side to the other short side of a rectangular metal plate, and the ring flange 115 can be formed by punching or cutting the metal plate.

[0043] The upper head plate 111 is mirror-finished and has a specified line engraved on it to indicate the liquid level when a specified amount is stored. Here, the "liquid level when a specified amount is stored" refers to the liquid level in the container when the specified amount of liquid 10 is stored, which is determined in advance as the limit of the amount of liquid 10 that can be stored within a range that is sufficiently safe for use. In this embodiment, the specified line is engraved at half the height of the container body 100.

[0044] The operator must fill the container with liquid 10 while paying attention to ensure that the actual liquid level does not exceed this specified line. For example, the liquid 10 can be filled through the second valve unit 300 without separating the liquid storage unit 110 and the lid unit 120. However, in this case, the actual liquid level cannot be visually confirmed, so the liquid is filled until the specified weight is reached while measuring the total mass. Alternatively, for example, the liquid storage unit 110 and the lid unit 120 can be separated in a glove box filled with inert gas, and the liquid 10 can be filled through a hole in the top of the liquid storage unit 110. In this case, the liquid can be filled while visually checking the actual liquid level and the specified line.

[0045] The bottom end plate 112 is also inclined, with the center being at the lowest position (A in Figure 3) and the position gradually increasing as it moves away from the center. By inclining the bottom of the container in this way, pressure resistance can be increased, and by removing the contents from near the lowest point, the contents can be removed efficiently even when they are low in content.

[0046] The lid 120 comprises a lid flange 121, a round packing 122, a lid connecting member 123, a cover 124, a butterfly bolt 125, a valve support 126, a valve support connecting member 127, a first valve connecting member 128, and a second valve connecting member 129. The lid flange 121 is a disk-shaped plate having a connecting surface with the ring flange 115. The round packing 122 is sandwiched between the ring flange 115 and the lid flange 121 to maintain a tight seal when they are joined. The lid connecting member 123 (six sets of bolts, nuts, and spring washers) presses the ring flange 115 and the lid flange 121 together with the round packing 122 sandwiched between them. The cover 124 protects the first valve unit 200 and the second valve unit 300. The butterfly bolts 125 (three pieces) are metal fittings for detachably attaching the cover 124 to the lid flange 121 without using tools. The valve support 126 is a mounting bracket for fixing the first valve section 200 and the second valve section 300 to the lid flange 121. A valve support connecting member 127 (two sets of a bolt and a flat washer) fixes the valve support 126 to the lid flange 121. A first valve connecting member 128 (two sets of a bolt and a flat washer) fixes the first valve section 200 to the valve support 126. A second valve connecting member 129 (two sets of a bolt and a flat washer) fixes the second valve section 300 to the valve support 126.

[0047] The lid 120 can be formed by casting or molding. For example, the lid flange 121 can be formed by stamping or cutting a metal plate.

[0048] <Detailed Description of First Valve Section 200> FIG. 4 is a cross-sectional view of the first valve section 200. As shown in FIG.

[0049] As shown in FIG. 4 , the first valve unit 200 includes a first valve 201 and an injection pipe 202 .

[0050] First valve 201 is a valve dedicated to inert gas, and injects inert gas 30 into container body 100. It is desirable that first valve 201 be a diaphragm valve. Injection pipe 202 may be a conduit that extends to a position within container body 100 that is higher than half the height of the container body (B in FIG. 3 ). Here, inert gas 30 injected by first valve 201 is guided to the end of injection pipe 202, and when inert gas 30 is guided to the end of injection pipe 202 (C in FIG. 3 ), which is higher than half the height of the container body, it is difficult for the liquid containing the borazine compound to be discharged from first valve 201.

[0051] <Detailed Description of Second Valve Section 300> FIG. 5 is a cross-sectional view of the second valve section 300. As shown in FIG.

[0052] As shown in FIG. 5 , the second valve unit 300 includes a second valve 301 and a discharge pipe 302 .

[0053] The second valve 301 is a valve dedicated to the liquid 10, and discharges the liquid containing the borazine compound from inside the container body 100 to the outside. The second valve 301 is preferably a diaphragm valve.

[0054] Discharge pipe 302 may be a conduit that extends to a position within container body 100 that is lower than half the height of the container body (B in FIG. 3). Here, the liquid containing the borazine compound that is discharged by second valve 301 is led to the tip of discharge pipe 302, and when led from a position of discharge pipe 302 (D in FIG. 3) that is lower than half the height of the container body, the liquid containing the borazine compound is easily discharged from second valve portion 300. Furthermore, if the tip of discharge pipe 302 (D in FIG. 3) extends above the lowest point of the bottom portion (A in FIG. 3), the contents can be discharged smoothly until only a small amount remains.

[0055] In the present invention, the liquid storage section of the sealed container is filled with a liquid containing a borazine compound, and after use for storage or transportation (for example, at a temperature of about 5 to 40°C, for a period of about 10 days to 4 months, with a liquid volume of 40 to 80% by volume of the total volume of the liquid storage section), the liquid containing the borazine compound stored in the liquid storage section is temporarily removed and washed. This procedure can be repeated. Even if the sealed container is refilled with a liquid containing a borazine compound after repeated use, the borazine compound can be stably stored or transported without deterioration. The liquid storage section of the sealed container can be cleaned by a method of filling the liquid storage section with a cleaning liquid and then draining it, ultrasonic cleaning, shower cleaning, immersion, or the like. The cleaning liquid used in these cleaning methods includes organic solvents such as hydrocarbon solvents and alcohol solvents, or water. Examples of hydrocarbon solvents include normal hexane, toluene, and xylene, with normal hexane being particularly preferred. Examples of alcohol solvents include ethanol and isopropyl alcohol, with isopropyl alcohol being particularly preferred. The water used for washing is preferably pure water, and pure water means water having an electrical conductivity of 1 μS / cm or less at 25°C. The electrical conductivity is preferably 0.5 μS / cm or less, more preferably 0.1 μS / cm or less, and even more preferably 0.05 μS / cm or less, and the lower limit may be about 0.01 μS / cm. That is, the electrical conductivity of pure water at 25°C is preferably 0.01 to 1 μS / cm, more preferably 0.01 to 0.5 μS / cm, even more preferably 0.01 to 0.1 μS / cm, and even more preferably 0.01 to 0.05 μS / cm. Pure water can be produced using a conventional water purification apparatus.

[0056] A preferred cleaning method is a method in which a cleaning liquid is filled into the liquid storage section and then discharged. More specifically, a method in which a cleaning liquid is filled in a volume that is 0.8 to 1.2 times the volume of the liquid containing the borazine compound filled into the liquid storage section, and the liquid is retained for about 1 second to 30 minutes and then discharged is preferred. It is more preferred that, after washing with a hydrocarbon solvent by this method, the liquid is washed with an alcohol solvent one to three times, and then washed with water (preferably pure water having the above-mentioned electrical conductivity) one to two times.

[0057] Furthermore, regardless of which cleaning method is adopted, it is preferable to dry the liquid storage section after completing all cleaning steps, and it is preferable to dry it at 40 to 60°C for about 30 to 70 hours.

[0058] In the present invention, the purity of the borazine compound contained in the liquid (the concentration of the borazine compound in the liquid) is preferably 99% or more, more preferably 99.3% or more, and the upper limit of the purity is most preferably 100%, but may be, for example, about 99.8%. That is, the purity of the borazine compound contained in the liquid is preferably 99 to 100%, more preferably 99.3 to 99.8%. Furthermore, the content of particles having a particle size of 0.5 μm or more contained in the liquid is preferably 100 particles / ml or less, more preferably 50 particles / ml or less, and even more preferably 20 particles / ml or less, and the lower limit is most preferably 0 particles / ml, but may be 1 particle / ml or 2 particles / ml. That is, the content of particles having a particle size of 0.5 μm or more contained in the liquid is preferably 0 to 100 particles / ml, more preferably 1 to 50 particles / ml, and even more preferably 2 to 20 particles / ml. Solid residues (polymers, decomposition products, etc.) may adhere to the inside of a container storing a borazine compound. If the borazine compound is stored in a container with such solid residues attached, the solid residues may have an adverse effect, causing the borazine compound to polymerize, resulting in the generation of particles and a decrease in the purity of the borazine compound. However, by repeating the procedure of storing a liquid containing a borazine compound in a sealed container of the present invention for 30 days and then performing the above-mentioned washing and drying once or twice or more times, the purity of the liquid containing the borazine compound after storing it in the sealed container for three months can be made to be a predetermined level or higher. Specific purity values ​​are, for example, a concentration of the borazine compound in the liquid of 99% or higher, preferably 99.3% or higher, with an upper limit of, for example, 99.8% (i.e., 99 to 99.8% is preferred, and 99.3 to 99.8% is more preferred), or the purity of the borazine compound in the liquid may be 97% or higher of the initial purity, with an upper limit of 99.8%.

[0059] The purity of the borazine compound can be determined, for example, by an internal standard method using gas chromatography. The particle content can be measured, for example, using a known particle counter, by measuring particles having a particle size of 0.5 μm or more.

[0060] This application claims the benefit of priority based on Japanese Patent Application No. 2023-140437, filed on August 30, 2023. The entire contents of the specification of Japanese Patent Application No. 2023-140437, filed on August 30, 2023, are incorporated herein by reference.

[0061] The present invention will be described in more detail below with reference to examples. The present invention is not limited to the following examples, and can of course be practiced with appropriate modifications within the scope of the above and below-described aims, all of which are included in the technical scope of the present invention.

[0062] <Preparation of Sealed Containers> A light-shielding sealed container (electropolished container A) made of stainless steel (SUS316) with the inner surface of the liquid storage section subjected to electropolishing, and a light-shielding sealed container (non-electropolished container B) made of stainless steel without the inner surface subjected to electropolishing were prepared. The volume of the liquid storage section of container A and container B was 2 L. The surface roughness (Ra) of "electropolished container A" was measured in accordance with JIS B0601 ('01), and the surface roughness Ra of container A was 0.1 μm, and the surface roughness Ra of container B was 1.2 μm. In addition, the pressure resistance of both container A and container B was 0.2 MPa.

[0063] Example 1 and Comparative Example 1 Each of the sealed containers, "Electropolished Container A" (Example 1) and "Unelectropolished Container B" (Comparative Example 1), was filled with N,N',N"-trimethylborazine in an amount equivalent to 60% by volume of the total capacity of the container together with nitrogen gas (dew point: -75°C), and stored at 25°C for one month. Thereafter, the filled liquid was once removed, and the inside of each container was washed twice with the same amount of normal hexane, then twice with the same amount of isopropyl alcohol, and subsequently washed for 30 minutes with ultrapure water (electrical conductivity at 25°C: 0.05 μS / cm. The same applies to ultrapure water hereinafter). After washing, each container was dried in an oven at 50°C for two days, and then again filled with N,N',N"-trimethylborazine in an amount equivalent to 60% by volume of the total capacity of the container together with nitrogen gas (dew point: -75°C), and stored at 25°C for one month.

[0064] The filled solution after storage was then removed, and the inside of each container was washed twice with the same amount of normal hexane, then twice with the same amount of isopropyl alcohol, and then washed for 30 minutes with ultrapure water. After drying each washed container in an oven at 50°C for 2 days, the containers were again filled with N,N',N"-trimethylborazine in an amount equivalent to 60% by volume of the total capacity of the container together with nitrogen gas (dew point -75°C), and stored at 25°C for 3 months.

[0065] After three months, the liquid in each container was analyzed by gas chromatography (GC) to determine its purity (GC purity), and the residual rate (%) of N,N',N"-trimethylborazine was calculated using the following formula, with the results shown in Table 1. Furthermore, after three months, the liquid in each container was measured for the content of particles having a particle size of 0.5 μm or more using a particle counter (LIQUIL AZ-SO2-HF, manufactured by Particle Measuring Systems Inc. (PMS)) that utilizes laser light scattering, and the increase in the number of particles was calculated from the corresponding value in the liquid before filling, and is also shown in Table 1. The purity (initial purity) of N,N',N"-trimethylborazine at the time of filling was 99.8%, and the content (initial particle number) of particles having a particle size of 0.5 μm or more was 12 particles / ml.

[0066] N,N',N"-trimethylborazine residual rate (%) = (GC purity after 3 months / GC purity at time of filling) x 100

[0067] The gas chromatography measurement conditions were as follows: Apparatus: GC-2014 manufactured by Shimadzu Corporation Column: Ultra Alloy-1 manufactured by Frontier Labs Carrier gas: Nitrogen Carrier gas flow rate: 3.0 mL / min Sample injection temperature: 200°C Detector temperature: 280°C Sample injection amount: 0.2 μL Column temperature: 50°C (4 min), heated to 280°C at a heating rate of 20°C / min, and 280°C (15 min)

[0068]

[0069] In the electropolished container A, which had a small surface roughness inside the container, the trimethylborazine residual rate remained almost unchanged and the increase in the number of particles in the solution was also small. On the other hand, in the unelectropolished container B, which had a large surface roughness inside the container, the trimethylborazine residual rate decreased and the increase in the number of particles in the solution also increased. From the above, it was found that high-purity borazine compounds can be stored stably for long periods in a container with a small surface roughness that has been electropolished, even when a container that has been repeatedly filled and cleaned is used.

[0070] REFERENCE SIGNS LIST 1 Package 10 Liquid 20 Sealed container 30 Inert gas 100 Container body 110 Liquid storage section 111 Upper head plate 112 Lower head plate 113 Skirt section 114 Neck section 115 Ring flange 120 Lid section 121 Lid flange 122 Rounded top packing 123 Lid connecting member 124 Cover 125 Butterfly bolt 126 Valve support 127 Valve support connecting member 128 First valve connecting member 129 Second valve connecting member 200 First valve section 201 First valve 202 Injection pipe 300 Second valve section 301 Second valve 302 Discharge pipe

Claims

1. A package comprising a liquid, a sealed container for storing the liquid, and a gas filling the space within the sealed container, wherein the liquid contains a borazine compound, the gas is an inert gas, the sealed container has a pressure resistance of 0.1 MPa or more and light-blocking properties, the sealed container has a liquid storage section, and the surface roughness (Ra) of the inner surface of the liquid storage section is 1.0 μm or less.

2. The package according to claim 1, wherein the airtight container has a container body including the liquid storage portion and at least two valves.

3. A package as described in claim 2, wherein of the two valves, the first valve is for injecting an inert gas into the container body, and the second valve is for discharging the liquid in liquid or gas form from within the container body to the outside.

4. The package according to claim 3, wherein the first valve and the second valve are both diaphragm valves.

5. A package according to claim 1 or 2, wherein the inner surface of the liquid storage section, which has a surface roughness (Ra) of 1.0 μm or less, is electrolytically polished.

6. A package according to claim 1 or 2, wherein the purity of the borazine compound contained in the liquid is 99% or more.

7. The package according to claim 1 or 2, wherein the borazine compound is represented by the structural formula (I). [In formula (I), R １1 , R １2 , R １３ , R ２１ , R ２２ and R ２３ may be the same or different and are a hydrogen atom or an alkyl group.

8. The package according to claim 1 or 2, wherein the gas filled in the space within the sealed container is an inert gas containing nitrogen gas or argon gas.

9. The package according to claim 1 or 2, wherein the dew point of the gas filled in the space within the sealed container is -70°C or lower.

10. A package as described in claim 3 or 4, wherein the sealed container further includes an injection pipe extending from the first valve and a discharge pipe extending from the second valve, the inert gas injected by the first valve is guided to the end of the injection pipe, and the liquid or gas discharged by the second valve is guided from the end of the discharge pipe.

11. A package as described in claim 2 or 3, wherein the container body has the liquid storage section located at the bottom and a lid section located at the top, all of the at least two valves are attached to the lid section, and the liquid storage section and the lid section are pressure-welded via a gasket.

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