JPH04362006A - Method for molding chemical oxygen-generating agent - Google Patents

Abstract

PURPOSE:To uniformly mold even a substance of relatively large size and in the complex shape without the danger of ignition by friction, etc., and to make do with only one pressurization-depressurization operation even for a candle of plural layers construction to simplify a manufacturing process. CONSTITUTION:A rubber mold 2 is filled with a powder component, 1 such as that containing a compound having the danger of ignition by friction with a metal mold while applying vibration. After the mold 2 is closed, it is pressurized in a solution 4 whose main component is water to mold it into the specified shape, causing a chemical oxygen-generating agent, such as a chlorate candle to be molded.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a method for molding a chemical oxygen generating agent for use in oxygen generators, and in particular to a method for molding a chemical oxygen generator for use in oxygen generators connected to individual breathing masks in aircrafts in the event of an aircraft depressurization accident. This invention relates to a molding method for safely producing oxygen generating agents that are relatively large in size and have complex shapes and layer structures in the production of oxygen generating agents such as chlorate candles that serve as oxygen generating sources.

0002

[Prior Art] Chlorate candles, which serve as the oxygen generation source for aircraft oxygen generators, are usually made of alkali metal chlorate as the main ingredient, transition metal powder as fuel, a catalyst that accelerates the thermal decomposition of chlorate, and chloric acid. It is obtained by molding into a cylindrical shape a powder component containing a metal oxide or peroxide to capture chlorine released during thermal decomposition of salt.

[0003] Chlorate candles are molded without using a binder so as not to generate toxic gases during use, and there are two methods for molding: wet and dry. The wet method is a method in which a powder component moistened with a highly volatile solvent such as trichlorofluoroethane is extruded into a predetermined shape by casting, and then dried at high temperature to remove the solvent. With this method, chlorate candles could only be molded with uniform dimensions, and it was also not possible to create a two-layered structure with a buried starting part that supplies the necessary amount of heat for thermal decomposition of the body during the initial stage of combustion. Furthermore, if the wetting solvent is incompletely removed, there is a risk of producing toxic gases during use.

[0004] Therefore, dry molding is often used, which usually involves filling a cylindrical cavity mold with powder, then sliding a compression ram into it and compressing it by applying a force of several tens of tons. . Compression is normally performed by applying force in the long axis direction, but if the candle size is large or the shape is complex, compression may be applied in the short axis direction. However, when compressing in the short axis direction, it is difficult to mold into a layered structure of two or more layers as described above due to the charging of raw materials, and after molding the main body part first, the combustion starting part is lengthened again. The actual situation is that they are compressed in the axial direction and buried.

[0005]

[Problems to be Solved by the Invention] As mentioned above, chlorate candles have been produced by filling powder into a metal cavity mold and compression-molding it by applying several tens of tons of force in the major or minor axis direction. However, depending on the size, shape, and structure of the candle, it had to be manufactured in multiple steps. For example, according to the example of Japanese Patent Publication No. 51-17152, after the main body part is molded, a part of it is removed and a combustion starting part that supplies the amount of heat necessary to start thermal decomposition of the main body is press-fitted. ing. Further, when the candle size becomes long, it is difficult to mold the candle to a uniform density by compression in the long axis direction, so there is also a literature in which compression molding is performed by applying force in the short axis direction. However, in this case as well, since the sample is filled into a lying cavity mold, it is difficult to fill it in a layered structure, and the combustion starting part must be press-fitted after the main body part has been molded.

Furthermore, since oxygen generators used in aircraft require a relatively large amount of oxygen within the first few minutes of use, the shape of the candles used is shaped like cylinders of different sizes connected together. Become. Furthermore, in the case of an oxygen generator for 2 to 5 people, the diameter of the candle will inevitably be large in order to supply the required amount of oxygen. In such a case,
With conventional pressing methods, it is difficult to obtain uniform molded products even when force is applied from the short axis direction. Moreover, the cavities and compression rams commonly used in conventional presses are made of metal, which creates friction between the sample and the cavity or ram during pressurization and depressurization, causing the sample to become self-combustible. There was a possibility that this could cause an accident such as a fire.

The purpose of the present invention is to solve these problems and provide a method for safely manufacturing oxygen generating agents such as chlorate candles, which are relatively large in size and have a complicated structure and shape, in a single process. That is.

[0008]

[Means for Solving the Problems] The present inventors have made extensive studies to solve the above problems, and as a result, have completed the present invention. That is, the present invention is a chemical method characterized in that a powder component is filled into a rubber mold while being vibrated, and after the mold is sealed, the powder component is pressurized in a solution mainly composed of water and molded into a predetermined shape. This relates to a method for molding a commercially available oxygen generating agent.

In the present invention, the solution containing water as a main component may be water alone or water mixed with a small amount of a rust-preventing agent or synthetic oil. The method of the present invention is a method for molding so-called chlorate candles in a cylindrical or block shape filled with a powder component containing a compound, such as sodium chlorate, which has a risk of ignition due to friction with a metal mold. It is suitable as Therefore, the present invention will be explained below using a chlorate candle as an example.

In the method of the present invention, a powder sample is first uniformly filled into a prescribed candle-shaped rubber mold. The rubber mold is usually made from one of urethane, silicone, natural rubber, etc., and its dimensions are determined by molding a powder sample into a simple shape in advance, and determining the pressure and holding time of the sample. Calculated and determined from the compression ratio. Filling is carried out with vibration on a shaker. This operation can remove air from the sample and achieve a uniform filling state. Chlorate candles usually have a layered structure in which a combustion initiation part containing fuel components at a higher content than the main body is embedded at one end in order to smoothly start thermal decomposition of the main body. After filling the components, a mold with a predetermined shape (dimensions are determined from the compression ratio) is pressed against the surface, giving the surface of the filled main component the same shape as the interface between the two layers, and forming a combustion starting part there. Fill the sample to be used. After filling the specified amount of sample, seal it with a lid made into a specified shape (seal with vinyl tape, etc. if necessary), and press the cold isostatic press filled with a solution whose main component is water. Immerse into the machine's pressure vessel. The system is pressurized using a pressurizing pump, maintained for a predetermined period of time, and then depressurized to remove the molded product. FIG. 1 shows an outline of the pressurization and depressurization of this cold isostatic press machine. That is, a rubber mold 2 filled with a powder sample 1 is placed in a pressure vessel 3 filled with a solution 4 mainly composed of water, the system is pressurized with a pressure pump, and the pressure is reduced after a predetermined period of time. Take out the molded product 5.

[0011] In the method of the present invention, since the inside of the pressure vessel is filled with a solution mainly composed of water, there is no risk of ignition due to friction as in the conventional pressing method using a metal cavity mold. do not have. In addition, as shown in Figure 1, since it is compressed with uniform force from all directions, it is possible to mold relatively large candles for 2 to 5 people, and even objects with complex shapes can be molded uniformly. , the oxygen flow rate of the product can be easily controlled; for example, in order to obtain different flow rates of oxygen in the early and late stages of combustion, candles can be molded with different dimensions at both ends. Furthermore, even in candles that have a multi-layer structure, such as one having a combustion initiation part containing a high percentage of thermal decomposition accelerator at one end, the pressurization and depressurization operations only need to be performed once, which can save labor in the manufacturing process.

0012

[Examples] The present invention will be explained in detail with reference to Examples below, but the present invention is not limited thereto in any way.

Example 1 A chlorate candle body component 6 containing a uniform mixture of sodium chlorate, reduced iron powder, etc. was placed in a mold 7 made of urethane rubber as shown in FIG. 3, and was uniformly mixed with vibration on a shaker. was filled. Thereafter, as shown in FIG. 2(a), vibration is applied again while pressing the stainless steel mold 8 against the main body sample 6, and as shown in FIG. 2(b).
A shape as shown in is attached to the surface of the main body sample 6. As shown in FIG. 4, the combustion starting part component 10 containing a higher proportion of fuel components than the main body sample 6 is gently added so that the surface does not lose its shape.
The container was filled with slight vibration. A stainless steel lid 9 prepared to provide a gap for filling the ignition powder on the surface of the starting part was attached (the ignition powder does not need to be press-fitted under high pressure) and sealed with vinyl tape. This was immersed in the pressure vessel of a cold isostatic press machine (manufactured by Nikkiso Co., Ltd., Model CL-22-60), a pressure of 3000 kgf/cm2 was applied, the pressure was maintained for 1 minute, the pressure was reduced, and the molded product was taken out. Ta. Figure 4 shows the chlorate candle after molding.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining the principle of cold isostatic pressing used in the method of the present invention.

FIG. 2 is a diagram for explaining the formation of layer interfaces in the method of the present invention.

FIG. 3 is a cross-sectional view of the molding rubber mold used in Example 1.

FIG. 4 is a cross-sectional view of the chlorate candle obtained in Example 1.

[Explanation of symbols]

1 Powder sample 2 Rubber mold 3 Pressure vessel 4. Solution whose main component is water 5 Molded products 6 Main body sample 7 Rubber mold 8 Stainless steel mold 9 Stainless steel lid 10　Combustion start part

Claims (5)

[Claims] [Claim 1] A chemical method characterized in that a powder component is filled into a rubber mold while being vibrated, the mold is sealed, and then pressurized in a solution mainly composed of water to mold it into a predetermined shape. Method of molding oxygen generating agent. [Claim 2] Claim 1, wherein the powder component contains a compound that has a risk of ignition due to friction with a metal mold.
Molding method described. [Claim 3] The compound that is at risk of igniting due to friction with the metal mold is mainly composed of sodium chlorate, and the predetermined shape is a cylindrical or block-shaped so-called chlorate candle. Molding method described. 4. The molding method according to claim 3, wherein the chlorate candle has a combustion initiation portion containing a high percentage of a thermal decomposition accelerator at one end. 5. The molding method according to claim 3, wherein the chlorate candle has different dimensions at both ends in order to obtain different flow rates of oxygen at the early and late stages of combustion.