JP2001122239A - Transportation container for high purity ammonia water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a container capable of performing a safety handling and capable of keeping high purity quality by restricting expansion of the container caused by increased pressure in the container as much as possible. SOLUTION: There is provided a multi-layered container in which its outer layer is made of stainless steel with a thickness of about 2 to 3 mm and its inner cylinder is made of either polyolefin or fluorine resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transport container for high-purity aqueous ammonia.

[0002]

2. Description of the Related Art In the field of the electronics industry, various high-purity chemicals are used for manufacturing semiconductors and liquid crystal display devices. For example, a high-purity hydrogen peroxide solution, a high-purity ammonia solution, a high-purity tetramethylammonium hydroxide aqueous solution, or the like is used. Since the presence of a small amount of impurities in these chemicals adversely affects the device characteristics of the semiconductor device,
The chemical must be of high purity. At present, the impurity concentration in a chemical solution has reached a level of the order of ppt. The material of the container for filling and transporting such a high-purity chemical solution must be one in which elution of impurities into the chemical solution is suppressed as much as possible. Materials suitable for this purpose include fluororesin and polyethylene such as high-density polyethylene. In particular, high-density polyethylene is widely used because it is inexpensive and less contaminated by the chemical solution, except for the problem of resin deterioration caused by the chemical solution. In addition, when the liquid is drained from a normal drum, the stopper is opened, and this opening may naturally cause contamination from the outside. To prevent this and maintain high purity, a one-touch connector is attached to the drum,
Filling and draining of the chemical solution into the container is performed via a one-touch connector. As a one-touch connector, a draining connector that drains by pumping up through an insertion tube inserted into the container, and clean nitrogen gas is introduced to prevent the container inner cylinder from contracting due to the pump-up force when draining A gas introduction connector and the like can be mentioned. Incidentally, the ammonia content of high-purity aqueous ammonia is usually about 29%. Since this concentration is close to the saturated dissolved amount at normal pressure, high-purity ammonia water has a high vapor pressure (when 28.5% ammonia water is used at 25 ° C
0.713 × 10 ⁵ Pa). Therefore, particularly at a high temperature, in a resin container containing high-purity ammonia water, the pressure of a mixed gas of ammonia gas and air evaporated in the space inside the container increases, and there is a problem in safety and quality. For example, in terms of safety, the expansion and breakage of the container, the resulting leakage of ammonia water and ammonia gas, the change in the shape of the container makes it impossible to stack containers during transportation and storage, and the ammonia gas suddenly blows out when the container is opened. There was such a problem. In terms of quality, there is a problem in that, for example, polyethylene, which is a liquid contact material, expands, and foreign matter is generated from polyethylene, thereby deteriorating the quality of the chemical solution. Further, in order to handle the drug solution in a closed manner, an insertion tube for draining the drug solution is inserted into the container, and this tube is fixed at a height reaching from the top plate to the container bottom. In the case of an ammonia container, the position of the drainage tube in the container moves due to the swelling of the top plate due to the above-mentioned pressure increase in the container, the tube does not reach the bottom of the container, and the ammonia water at the bottom cannot be completely drained. May remain.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to develop a container which enables safe handling and maintains high purity quality by minimizing the expansion of the container due to an increase in pressure in the container. It is in.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, the outer casing is made of stainless steel, the inner cylinder is a multi-layer container of polyolefin or fluororesin, and It has been found that setting the thickness of stainless steel to 2 to 3 mm is extremely effective, and the present invention has been completed. The features of this container are described below. The thicker the outer stainless steel, the heavier the weight of the entire container. On the other hand, the thinner the stainless steel, the sharper the expansion of the container shape due to the increase in the internal pressure of the container. Stainless steel with a thickness of 2-3 mm is preferred because it creates a danger. As described above, when ammonia leaks, there is a risk that even a small amount emits a strong pungent odor. Therefore, it is necessary to prevent leakage as much as possible. Therefore, it is preferable to use a fluororesin elastomer for the connection portion between the container body and the connector and the valve portion in the connector in order to maintain gas sealing inside the container. Examples of the polyolefin in the inner cylinder, which is a liquid contact part of the container, include at least one selected from polyethylene, polypropylene, polybutylene, and a copolymer thereof. High-density polyethylene is particularly preferred as a material that minimizes the elution of contaminants such as eluted and degraded products of the resin into high-purity aqueous ammonia and can be used for a long period of time. Further, the high-density polyethylene preferably contains no additives such as antioxidants and light stabilizers.

[0005] The fluororesin of the inner cylinder which is a liquid contact part of the container includes polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene. Copolymer (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) and the like can be mentioned. As a resin that can minimize the elution of contaminants such as eluted and degraded products of the resin and can be used for a long period of time, particularly, a tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (PFA)
Is preferred.

[0006]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. The measured swelling height of the container top plate was measured by the method shown in FIG. That is, A is the height from the surface of the container top plate immediately after filling to the top of the container periphery, and B is the height from the surface of the container top plate to the top of the container periphery 48 hours after filling, and A The difference (A-B) between B and B was defined as the swelling height.

Embodiment 1 A drum body a shown in FIG. 1 is provided with a liquid-side connector b, a gas-side connector c and an insertion tube d, and has a capacity of 200 liters.
A drum having an inner cylinder made of high-density polyethylene and an exterior made of stainless steel (2 mm thick) was prepared. The drum was filled with 190 liters of high-purity ammonia water e. Then 35 ° C
After standing in the atmosphere for 48 hours, the swelling height of the container top plate was measured in order to measure the degree of expansion of the container shape due to an increase in the pressure inside the container. After observing the external shape and conducting a two-stack test of the drum, high-purity ammonia water is drained. For the remaining liquid that cannot be completely drained, open the drum stopper, invert the drum, and extract the amount. Was measured. Table 1 shows the above results.

Comparative Example 1 Example 1 except that the thickness of the exterior stainless steel was 1 mm.
The same was done. Table 1 shows the results.

[0009]

[Table 1]

[0010]

According to the present invention, the thickness of the stainless steel of the container exterior is set to 2-3.
By setting mm, the expansion of the container due to an increase in pressure inside the container is suppressed as much as possible, and safe handling is enabled, and the drainage of aqueous ammonia can be suitably performed.

[Brief description of the drawings]

Fig. 1 Cross section of drum for high purity ammonia water

FIG. 2 Measurement method of bulge height

[Explanation of symbols]

 a Drum body b Liquid side connector c Gas side connector d Insertion tube e High-purity ammonia water

Continued on the front page (72) Inventor Yasushi Sugawara 2-5-2-2 Marunouchi, Chiyoda-ku, Tokyo F-term (reference) 3R033 AA06 BA08 BA13 BA14 BA15 BB08 DA02 DD01 GA02

Claims (4)

[Claims] 1. A transport container for high-purity ammonia water, wherein the inner cylinder is made of polyolefin or fluororesin, and the exterior is made of stainless steel having a thickness of 2 to 3 mm. 2. The transport container according to claim 1, wherein the polyolefin is high-density polyethylene. 3. The high-purity aqueous ammonia having an ammonia concentration of 2
The transport container for high-purity ammonia water according to claim 1, which has a content of 8 to 30%. 4. The transport container according to claim 1, wherein the fluororesin is a tetrafluoroethylene-perfluoroalkylvinyl ether copolymer.