JP7550282B1 - Packaging - Google Patents

Abstract

[Problem] The objective is to provide a package including a container and a borazine compound that can safely store or transport a borazine compound without deteriorating the borazine compound even if the borazine compound is repeatedly stored in the container. [Solution] The package includes a liquid, a sealed container for storing the liquid, and a gas filling the space inside the sealed container, the liquid containing a borazine compound, the gas being an inert gas, the sealed container having a pressure resistance of 0.1 MPa or more and a light-shielding property, the sealed container having a liquid storage section, and the surface roughness (Ra) of the inner surface of the liquid storage section being 1.0 μm or less. [Selected Figure] Figure 3

Description

The present invention relates to a package that includes a liquid to be stored or transported, a sealed container for storing the liquid, and a gas filling the space inside the sealed container, and in particular to a package that includes a liquid that contains a borazine compound.

As semiconductor elements 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 that have a borazine skeleton in the molecule as materials that exhibit a low dielectric constant.

Conventionally, borazine compounds have been synthesized in small quantities 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. In particular, materials for semiconductors require high purity in terms 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. As a technology to solve this problem, Patent Document 3 discloses a method for cleaning a container for storing borazine compounds, which is characterized by having a step of cleaning the container for storing borazine compounds 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.

JP 2000-340689 A JP 2003-119289 A JP 2008-110940 A

Containers for transporting or storing borazine compounds may be reused after cleaning, but solid residues such as polymerized products of the borazine compounds or decomposition products caused by trace amounts of oxygen may adhere to the inner surface of the container once it has been used to store the borazine compounds. Once these solid residues adhere to the inside of the container, they are difficult to completely remove by cleaning with ordinary solvents, and the amount of solid residues adhering to the inner surface tends to increase with repeated use of the container.

The inventors' investigations revealed that even a small amount of this solid residue can 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.

The present invention aims to provide a package including a container and a borazine compound that can safely store or transport the borazine compound without causing deterioration of the borazine compound even when the borazine compound is repeatedly stored therein.

［式（Ｉ）中、Ｒ^１1、Ｒ^１2、Ｒ^１３、Ｒ^２１、Ｒ^２２及びＲ^２３は同一であっても異なっていてもよく、水素原子またはアルキル基である。］
［８］前記密閉容器内の空間に充填された気体が、窒素ガスまたはアルゴンガスを含む不活性ガスである［１］～［７］のいずれかに記載の梱包体。
［９］前記密閉容器内の空間に充填された気体の露点が－７０℃以下である請求項［１］～［８］のいずれかに記載の梱包体。
［１０］前記密閉容器は、更に前記第１バルブから伸びた注入パイプと、前記第２バルブから伸びた吐出パイプとを含み、
前記第１バルブにより注入される前記不活性ガスは、前記注入パイプの先へ導かれ、
前記第２バルブにより吐出される前記液体または気体は、前記吐出パイプの先から導かれる［３］～［９］のいずれかに記載の梱包体。
［１１］前記容器本体は、下側に位置する前記液体収納部と、上側に位置する蓋部とを有し、
前記蓋部には、前記少なくとも２個のバルブの全てが取付けられており、
前記液体収納部と前記蓋部とは、パッキンを介して圧接されている［２］～［１０］のいずれかに記載の梱包体。 The present invention which achieves the above object is as follows.
[1] A package including a liquid, a sealed container for storing the liquid, and a gas filled in a space within the sealed container,
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 a light-shielding property,
The sealed container has a liquid storage section,
A package characterized in that the surface roughness (Ra) of the inner surface of the liquid storage section is 1.0 μm or less.
[2] The package described in [1], wherein the sealed container has a container body having the liquid storage section and at least two valves.
[3] A packaging body as described in [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 gaseous form from inside the container body to the outside.
[4] The packaging body described in [3], wherein the first valve and the second valve are both diaphragm valves.
[5] A package according to any one of [1] to [4], wherein the inner surface of the liquid storage section, which has a surface roughness (Ra) of 1.0 μm or less, is subjected to electrolytic polishing.
[6] The package according to any one of [1] to [5], wherein the purity of the borazine compound contained in the liquid is 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 ²³ may be the same or different and each represents a hydrogen atom or an alkyl group.]
[8] The package described in any one of [1] to [7], wherein the gas filled in the space within the sealed container is an inert gas including nitrogen gas or argon gas.
[9] The package according to any one of claims [1] to [8], wherein the dew point of the gas filled in the space within the sealed container is -70°C or lower.
[10] 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 tip of the injection pipe,
The package according to any one of [3] to [9], wherein the liquid or gas discharged by the second valve is guided from the end of the discharge pipe.
[11] The container body has the liquid storage section located on the lower side and a lid section located on the upper side,
The at least two valves are all attached to the lid,
The packaging body according to any one of [2] to [10], wherein the liquid storage section and the lid section are pressure-welded via a packing.

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

1 is a diagram showing the appearance of one embodiment of a package according to the present invention; FIG. 2 is a top view of FIG. 1 . 2 is a cross-sectional view taken along line AA of FIG. 1. FIG. 2 is a cross-sectional view of an embodiment of a first valve portion of the present invention. FIG. 2 is a cross-sectional view of an embodiment of the second valve portion of the present invention.

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

In the present invention, the term "borazine compound" is used to include 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.

The borazine compound is preferably 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 each represents a hydrogen atom or an alkyl group.]

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

In formula (I), it is preferable that at least one of R ¹¹ , R ¹² , R ¹³ , R ²¹ , R ²² and R ²³ is not a hydrogen atom, and it is more preferable that R ²¹ , R ²² and R ²³ are hydrogen atoms and R ¹¹ , R ^{12 and R 13 are alkyl groups. When R 21 , R 22 and R 23 are} hydrogen atoms, R ¹¹ , R ¹² and R ¹³ are more preferably alkyl groups having 1 to 4 carbon atoms, further preferably methyl groups or ethyl groups, and most preferably methyl groups (i.e., the borazine compound represented by formula (I) is N,N',N''-trimethylborazine).

There are no particular limitations on the route by which the borazine compound can be obtained. For example, if the borazine compound is commercially available, it may be purchased and stored in a sealed container, or it may be prepared by the user and stored. The method for preparing the borazine compound may be a known method, and the borazine compound may be prepared by referring to the description in, for example, [0027] to [0034] of the above-mentioned Patent Document 3.

The liquid containing the borazine compound is usually the borazine compound itself, but may contain components such as a solvent other than the borazine compound, and may contain the solvent (reaction solvent) used in synthesizing the borazine compound. The content of the borazine compound 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 or more. 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.

The inert gas is a gas that does not react with the borazine compound. 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.

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 there is no particular limit, it may be -80°C.

The following describes the packaging body according to the embodiment with reference to the drawings, but the present invention is not limited to the embodiment described below, and it is of course possible to make appropriate modifications within the scope of the purpose described above and below.

Figure 1 is a diagram showing the appearance of a package 1 according to the present invention. As shown in Figure 1, the package 1 includes a liquid 10 containing a borazine compound, a sealed container 20 that contains the liquid 10, and an inert gas 30 that fills the space of the sealed container 20.

It is preferable that the sealed container 20 has a container body and at least two valves. Of the two valves, it is preferable that the first valve injects an inert gas into the container body, and the second valve introduces an inert gas into the container body or heats the container body from the outside to discharge the liquid in liquid or gas form from inside the container body to the outside.

<Description 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.

Figure 3 is a cross-sectional view of A-A in Figure 1.

As shown in Figures 2 and 3, the sealed container 20 is a sealed container that contains a liquid containing a borazine compound, has a liquid storage section 110, and is equipped with a container body 100, a first valve section 200, and a second valve section 300. Note that in Figure 3, the container body 100 is cut approximately from the center, and the conduit sections of the first valve section 200 and the second valve section 300 are cut approximately from the center.

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

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 equipped with a valve dedicated to inert gas.

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

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

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, etc., it is preferably 5.0 MPa or less, and more preferably 2.0 MPa or less.

The sealed container 20 is not only airtight and pressure resistant, but also has light-shielding properties, and is therefore formed from a material with light-shielding properties. Having light-shielding properties means that the light transmittance is substantially zero. In this embodiment, the entire container body 100 and at least the first valve section 200 and the second valve section 300 parts that affect the light-shielding properties are made of stainless steel, thereby achieving high light-shielding properties. There are no particular limitations on the material with light-shielding properties, and in addition to stainless steel, metal materials such as corrosion-resistant alloys (e.g., Hastelloy (registered trademark), MAT series and MA series manufactured by MMC Superalloy Co., Ltd.) can also be used.

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. 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 normal cleaning, making it possible to stably store the borazine compound without deterioration.

In this invention, "surface roughness (Ra)" refers to the arithmetic mean roughness defined in JIS B0601 ('01).

It is preferable that the inner surface of the liquid storage section, the surface roughness of which is adjusted to the above range, is subjected to electrolytic polishing. By subjecting the inner surface of the container to 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 adopted, and the treatment conditions may be appropriately set so as to achieve the desired surface roughness (Ra).

The liquid containing the borazine compound is preferably filled in an amount of 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.

The sealed container 20 may have at least two valves, one dedicated to the inert gas and one dedicated to the liquid containing the borazine compound, but other valves may be added to increase the number of valves to more than two. For example, if the number of valves is increased to more than two, valves of different diameters or shapes can be used depending on the application, or the number of valves to be used can be changed depending on the amount of use. The connection part of the valve dedicated to the inert gas and the connection part of the valve dedicated to the liquid 10 may be made to have different shapes that are incompatible with each other to prevent incorrect connection. A check valve may be added to the first valve section 200 to prevent the inert gas 30 and the liquid 10 from leaking from inside the container body 100 to the outside. A check valve may be added to the second valve section 300 to prevent the liquid 10 from flowing back or to prevent outside air from entering the container body 100 from the outside.

Furthermore, in addition to the two or more valves, the sealed container 20 may have a configuration in which one or more ports are opened in the container body 100 (not shown). Using this port, it is possible to easily fill the container with liquid or clean the container. The diameter of the port is not particularly limited, but it is preferable that the port is 5 mm or larger in size from the viewpoint 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 the cap has a screw-type closure to ensure pressure resistance and airtightness.

<Detailed Description of Container Body 100>
Next, one embodiment of the container body 100 is 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. When more than two valves are used, all of the valves are attached to the lid section 120.

In one embodiment of the container body 100, the liquid storage section 110 and the lid section 120 are pressed together via a packing, and are pressed together via a rounded packing 122. The liquid storage section 110 and the lid section 120 may be integrated together like a seamless container without a flange. In addition, a glove box (not shown) may be filled with an inert gas, and the liquid storage section 110 and the lid section 120 may be separated within the glove box to fill the liquid storage section 110 with liquid or to drain the liquid from the liquid storage section 110.

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, but does not necessarily have to have the neck portion 114. 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 molded by drawing, the skirt portion 113 and the neck portion 114 can be molded by welding one short side and the other short side of a rectangular metal plate, and the ring flange 115 can be molded by punching or cutting the metal plate.

The upper mirror plate 111 is mirror-finished and has a specified line engraved on it, which indicates the height of the liquid level when a specified amount is stored. Here, "the height of the liquid level when a specified amount is stored" refers to the height of the liquid level in the container when a specified amount of liquid 10 is stored, which is determined by pre-determining 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 1/2 the height of the container body 100.

The operator must fill the 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 from the second valve section 300 without separating the liquid storage section 110 and the lid section 120. In this case, however, the actual liquid level cannot be visually observed, so the liquid is filled until the specified weight is reached while measuring the total mass. In addition, for example, the liquid storage section 110 and the lid section 120 can be separated in a glove box filled with inert gas, and the liquid 10 can be filled from a hole in the top of the liquid storage section 110. In this case, the liquid can be filled while visually observing the actual liquid level and the specified line.

The lower head plate 112 is also inclined, with the center being at the lowest position (A in Figure 3) and gradually increasing in position 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 there is only a little left.

The lid part 120 is composed of a lid flange 121, a round packing 122, a lid joint member 123, a cover 124, a butterfly bolt 125, a valve support 126, a valve support joint member 127, a first valve joint member 128, and a second valve joint member 129. The lid flange 121 is a disk-shaped plate having a joint surface with the ring flange 115. The round packing 122 is sandwiched between the ring flange 115 and the lid flange 121 to maintain airtightness when joined. The lid joint member 123 (six sets of bolts, nuts, and spring washers) presses the ring flange 115 and the lid flange 121 with the round packing 122 sandwiched between them. The cover 124 protects the first valve part 200 and the second valve part 300. The butterfly bolts 125 (three pieces) are metal fittings for attaching the cover 124 to the lid flange 121 in a detachable manner 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. The valve support connecting member 127 (two sets of bolts and flat washers) fixes the valve support 126 to the lid flange 121. The first valve connecting member 128 (two sets of bolts and flat washers) fixes the first valve section 200 to the valve support 126. The second valve connecting member 129 (two sets of bolts and flat washers) fixes the second valve section 300 to the valve support 126.

Here, the lid portion 120 can be formed by casting or molding. For example, the lid flange 121 can be formed by punching or cutting a metal plate.

<Detailed Description of First Valve Section 200>
FIG. 4 is a cross-sectional view of the first valve section 200.

As shown in FIG. 4, the first valve section 200 includes a first valve 201 and an injection pipe 202.

The first valve 201 is a valve dedicated to inert gas, and injects the inert gas 30 into the container body 100. The first valve 201 is preferably a diaphragm valve. The injection pipe 202 may be a conduit extending to a position inside the container body 100 that is higher than 1/2 the height of the container body (B in FIG. 3). Here, the inert gas 30 injected by the first valve 201 is guided to the end of the injection pipe 202, and when the inert gas 30 is guided to a position higher than 1/2 the height of the container body at the end of the injection pipe 202 (C in FIG. 3), it is difficult for the liquid containing the borazine compound to be discharged from the first valve 201.

<Detailed Description of Second Valve Section 300>
FIG. 5 is a cross-sectional view of the second valve section 300.

As shown in FIG. 5, the second valve section 300 includes a second valve 301 and a discharge pipe 302.

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. It is preferable that the second valve 301 is a diaphragm valve.

The discharge pipe 302 may be a conduit that extends to a position within the container body 100 that is lower than 1/2 the height of the container body (B in FIG. 3). Here, the liquid containing the borazine compound discharged by the second valve 301 is guided to the end of the discharge pipe 302, and when the liquid is guided from the discharge pipe 302 (D in FIG. 3) that is lower than 1/2 the height of the container body, the liquid containing the borazine compound is easily discharged from the second valve section 300. Furthermore, if the end of the discharge pipe 302 (D in FIG. 3) extends above the lowest point of the bottom part (A in FIG. 3), the contents can be discharged smoothly until only a small amount remains.

In addition, the liquid storage section of the sealed container in the present invention is filled with a liquid containing a borazine compound, and used 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, and with a liquid filling amount of 40 to 80% by volume of the total volume of the liquid storage section), and then the liquid containing the borazine compound filled in the liquid storage section is once extracted and washed. This operation can be repeated, and even if the sealed container is filled with a liquid containing a borazine compound again after repeated use in this way, 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 discharging it, an ultrasonic cleaning method, a shower cleaning method, or a soaking method. Examples of cleaning liquids used in these cleaning methods include organic solvents such as hydrocarbon solvents and alcohol solvents, or water. Examples of hydrocarbon solvents include normal hexane, toluene, and xylene, and normal hexane is particularly preferred. Examples of alcohol solvents include ethanol and isopropyl alcohol, and isopropyl alcohol is particularly preferred. The water used for cleaning 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. Pure water can be produced using a normal water purification device.

The preferred cleaning method is to fill the liquid storage section with cleaning liquid and then drain it. More specifically, the preferred method is to fill the liquid storage section with cleaning liquid with a volume 0.8 to 1.2 times the volume of the liquid containing the borazine compound that was filled in the liquid storage section, hold it for about 1 second to 30 minutes, and then drain it. It is more preferred to wash 1 to 3 times with a hydrocarbon solvent using this method, then wash 1 to 3 times with an alcohol solvent, and then wash 1 to 2 times with water.

Regardless of which cleaning method is used, it is preferable to dry the liquid storage section after all cleaning steps are completed, and it is preferable to dry it at 40 to 60°C for about 30 to 70 hours.

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. In addition, the content of particles with a particle diameter 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. Solid residues (polymerized products, decomposition products, etc.) may adhere to the inside of a container storing a borazine compound, and 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 tendency for the purity of the borazine compound to decrease. However, by storing a liquid containing a borazine compound in the sealed container of the present invention for 30 days and repeating the above-mentioned washing and drying operations once or twice or more, 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 (for example, the concentration of the borazine compound in the liquid is 99% or higher, preferably 99.3% or higher, or the purity of the borazine compound in the liquid is 97% or higher of the initial purity).

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, for example, by measuring particles with a particle size of 0.5 μm or more.

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 modified as appropriate within the scope of the above and below-described aims, and all such modifications are within the technical scope of the present invention.

<Preparing a sealed container>
A light-shielding sealed container made of stainless steel (SUS316) with the inner surface of the liquid storage section subjected to electrolytic polishing (electrolytically polished container A) and a light-shielding sealed container made of stainless steel with the inner surface not subjected to electrolytic polishing (non-electrolytically polished container B) were prepared. The volume of the liquid storage section of container A and container B was 2 L. When the surface roughness (Ra) of "electrolytically polished container A" was measured in accordance with JIS B0601 ('01), 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.

Example 1
Each of the sealed containers of the above "container A subjected to electrolytic polishing" and "container B not subjected to electrolytic polishing" was filled with N,N',N"-trimethylborazine in an amount equivalent to 60% by volume of the total volume 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 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 (electrical conductivity at 25 ° C. is 0.05 μS / cm. The same applies to ultrapure water below). After drying each washed container in an oven at 50 ° C. for two days, N,N',N"-trimethylborazine in an amount equivalent to 60% by volume of the total volume of the container was filled again together with nitrogen gas (dew point: -75 ° C.) and stored at 25 ° C. for one month.

The filled liquid 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 each washed container was dried in an oven at 50°C for two days, it was 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 three months.

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. After three months, the liquid in each container was measured for the content of particles with 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 uses laser light scattering, and the increase in particle number 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 with a particle size of 0.5 μm or more was 12 particles/ml.

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

The measurement conditions for the gas chromatography are as follows:
Equipment: Shimadzu Corporation GC-2014
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 volume: 0.2 μL
Column temperature: 50°C (4 min), heated to 280°C at a heating rate of 20°C/min, 280°C (15 min)

In container A, which had been electrolytically polished and had a small surface roughness inside, the trimethylborazine residual rate remained almost unchanged and the increase in the number of particles in the liquid was also small. On the other hand, in container B, which had not been electrolytically polished and had a large surface roughness inside, the trimethylborazine residual rate decreased and the increase in the number of particles in the liquid also increased. From the above, it was found that high-purity borazine compounds can be stably stored for long periods in a container with a small surface roughness that has been electrolytically polished, even when the container has been repeatedly filled and cleaned.

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 Round-top packing 123 Lid joint member 124 Cover 125 Wing bolt 126 Valve support 127 Valve support joint member 128 First valve joint member 129 Second valve joint member 200 First valve section 201 First valve 202 Injection pipe 300 Second valve section 301 Second valve 302 Discharge pipe

Claims (11)

A package including a liquid, a sealed container for storing the liquid, and a gas filling a space in the sealed container,
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 a light-shielding property,
The sealed container has a liquid storage section,
A package characterized in that the surface roughness (Ra) of the inner surface of the liquid storage portion is 0.5 μm or less. The package according to claim 1, wherein the sealed container has a container body including the liquid storage section and at least two valves. The package according to claim 2, wherein the first valve of the two valves injects an inert gas into the container body, and the second valve discharges the liquid in liquid or gas form from inside the container body to the outside. The package according to claim 3, wherein the first valve and the second valve are both diaphragm valves. 3. The package according to claim 1, wherein the inner surface of the liquid storage section, which has a surface roughness (Ra) of 0.5 μm or less, is electrolytically polished. The package according to claim 1 or 2, wherein the purity of the borazine compound contained in the liquid is 99% or more. 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 each represents a hydrogen atom or an alkyl group.] The package according to claim 1 or 2, wherein the gas filled in the space inside the sealed container is an inert gas containing nitrogen gas or argon gas. The package according to claim 1 or 2, wherein the dew point of the gas filled in the space inside the sealed container is -70°C or lower. 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 tip of the injection pipe,
5. The package according to claim 3, wherein the liquid or gas discharged by the second valve is guided from the end of the discharge pipe. The container body has the liquid storage section located on a lower side and a lid section located on an upper side,
The at least two valves are all attached to the lid,
4. The package according to claim 2, wherein the liquid storage section and the lid section are pressure-welded via a packing.

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