JP2769543B2 - Test method for stability of explosives - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for testing the stability of nitrate ester explosives used in propellants and rocket propellants.

[0002]

2. Description of the Related Art Conventionally, techniques in such a field include:
For example, there is one disclosed in the following literature. (1) Junichi Kimura Journal of the Pharmaceutical Society of Japan “EXPLOSIO
N "Vol. 4, No. 2, 1994, p. 63-6
9 (2) Junichi Kimura Defense Technology July 1992 p.
16 (3) Masao Tanaka, Shoji Koma, Phthalocyanine (Bunshin Publishing) p. 68-p. 76 (4) Japanese Patent Application No. 7-025743 proposed by the inventor of the present application
No. Explosives have an unstable chemical bond (C—N, O—
(N, NN) can be regarded as a self-heating substance. Therefore, spontaneous decomposition occurs without the presence of air even at around normal temperature, generating decomposition gas and heat, sometimes leading to ignition, which may cause a great disaster.

[0003] As an example of an actual disaster, nitrocellulose stored in a drum in a warehouse in Shinagawa, Tokyo in the summer of 1964 in a wet state dries in a hot summer and causes spontaneous ignition.
In some cases, this fire triggered a massive explosion of organic peroxide, resulting in numerous casualties. The problem of spontaneous decomposition in the storage temperature range is a nitrate ester having a weak ON bond and explosives containing this as a main component. Recently, the use of nitrates in the field of industrial explosives has declined due to a significant drop in dynamite production, but in the field of military explosives, almost all propellants and smokeless rocket propellants are still the main players. The component is a nitrate ester. For military personnel, it is necessary to estimate the useful life of stockpiled ammunition and to establish robust disposal standards to ensure safety.

[0004] As a method for testing the stability of nitrate ester explosives, as described in the above-mentioned references (1) and (2), nitrogen oxides generated by decomposition from explosives have been long. The measurement of NOx has been performed by a surveillance test or an Abel test. In the surveillance test, 45 g of a sample was taken in a transparent wide-mouthed bottle (about 50 mm in inner diameter, 140 mm in height).
Store it in a heating tank kept at 5.5 ° C and observe it visually until the concentration of generated NO ₂ red smoke becomes equivalent to that of NO ₂ enclosed in an ampoule. And is being implemented at military ammunition-related facilities.

[0005] In the Abel test, NOx generated from a sample heated to 65.5 ° C is used to visually observe the time required for the reference color (light purple) to appear at the boundary between the wetness of the potassium iodide starch test paper and the dry boundary. And determines whether or not it can be used according to the required time.

[0006]

However, the surveillance test requires a period of several months to several years to obtain a judgment result, and the judgment is performed visually, so that the judgment involves ambiguity. there were. On the other hand, in the Abel test, the judgment can be made in a few minutes, but in this test, the judgment is made visually, and thus there is a problem that the judgment is also accompanied by ambiguity.

As described in the above-mentioned references (1) and (2), surveillance has recently been used to solve such problems and to speed up and standardize the stability test method for nitrate ester explosives. Attempts to replace the test and abel test with a simple NOx meter using a semiconductor photodetector, quantitative analysis of stabilizers by various chromatographs, a calorimetric method with a microcalorimeter, and a chemiluminescent method with an ultra-low light meter It has been done.

However, even these methods have problems that the apparatus is expensive and the measurement procedure is complicated, and has not yet been put to practical use. On the other hand, the present inventors have paid attention to the fact that various gases are adsorbed on the phthalocyanine thin film as shown in the above-mentioned document (3). Then, as shown in the above reference (4), NOx generated due to the decomposition of explosive is detected by using a gas sensor element having phthalocyanines as a sensitive film,
A method for testing the stability of nitrate-based explosives was provided. For example, when an element that measures a change in electric resistance of the sensitive film due to gas adsorption is used as the gas sensor element, by measuring the time until the electric resistance reaches a reference value, or by measuring the electric resistance. Degree of change,
That is, the stability of the explosive can be determined by using the time constant as a parameter.

However, it has not been clarified until now what parameters can be used to determine the explosive stability most quickly, accurately and with good reproducibility. Therefore, the present invention eliminates the above problems, a phthalocyanine as a sensitive film, using a gas sensor element that measures the change in electrical resistance of the sensitive film due to gas adsorption, by detecting NOx generated from explosives,
In a method for testing the stability of a nitrate ester explosive,
An object of the present invention is to provide an explosive stability testing method capable of quickly and accurately determining the stability of an explosive with good reproducibility.

[0010]

In order to achieve the above object, the present invention provides: (1) a phthalocyanine as a sensitive film, using a gas sensor element for measuring a change in electric resistance of the sensitive film due to gas adsorption; A method for testing the stability of a nitrate-based explosive by detecting NOx generated from the explosive,
Immediately after exposing the gas sensor element to NOx generated from an explosive, the electric resistance value of the gas sensor element becomes 1 / A (A is 1
(A larger real number).

Therefore, the stability of the explosive can be quickly and accurately determined with good reproducibility. (2) In the explosive stability test method according to the above (1), the gas sensor element measures a change in electric resistance of the sensitive film using a comb-shaped electrode.

Therefore, the stability of the explosive can be determined quickly, accurately and reproducibly with a small and simple gas sensor element. (3) In the method for testing the stability of explosives according to the above (1), when exposing the gas sensor element to the NOx,
The NOx is introduced and flown into the installation location of the gas sensor element by a carrier gas.

Therefore, it is possible to prevent the concentration of NOx exposed to the gas sensor element from changing with time and the change in electric resistance of the gas sensor element from becoming unstable.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings. Using a phthalocyanine as a sensitive film, using a gas sensor element that measures the change in electrical resistance of the sensitive film due to gas adsorption, for NOx,
When the rate of change at which the electric resistance becomes 1 / A (A is a real number greater than 1) was measured immediately after exposing the gas sensor element to the NOx, it was found that the rate of change was dependent on the NOx concentration. Further, they have found that the rate of change does not depend on the variation of the initial resistance value of the gas sensor element.

Therefore, the present invention uses a phthalocyanine as a sensitive film, and uses a gas sensor element for measuring a change in the electric resistance of the sensitive film due to gas adsorption.
In the method for testing the stability of a nitrate-based explosive by detecting x, the gas sensor element is exposed to the NOx immediately after the gas sensor element has an electric resistance value of 1
By measuring the rate of change to / A (A is a real number greater than 1), the stability of the explosive can be determined quickly and accurately and with good reproducibility.

Further, in the present invention, it is preferable to use a gas sensor element which measures a change in electric resistance of the phthalocyanine-sensitive film using a comb-shaped electrode. Further, in the present invention, when exposing the gas sensor element to NOx, it is preferable that the NOx be introduced and flown into the gas sensor element installation location by a carrier gas so that the concentration of NOx does not fluctuate with time.

[0017]

FIG. 1 is a plan view of a gas sensor element showing a first embodiment of the present invention. As shown schematically in this figure, a gold thin-film electrode was deposited on a glass substrate 11 having a size of 10 mm × 15 mm and a thickness of 1 mm.
A comb-shaped electrode 13 having 0 μm and a comb tooth width of 50 μm is formed,
A gas sensor element 10 having a copper phthalocyanine sensitive film 14 in which copper phthalocyanine (manufactured by Toyo Ink Co., Ltd.) was vacuum-deposited on the glass substrate 11 on which the comb-shaped electrode 13 was formed was used. The deposition of the phthalocyanine sensitive film 14
0 mg was placed in an alumina crucible, and the crucible was heated by resistance wire. The substrate was not heated or cooled, and a sensitive film having a thickness of 0.2 μm was formed at a vacuum degree of 10 ⁻³ Pa or less at a deposition rate of 0.5 to 2.0 ° / sec. Reference numeral 12 denotes a connection terminal of the comb-shaped electrode.

Next, the response characteristics of the gas sensor element 10 thus manufactured to various concentrations of NO ₂ were measured as follows. First, after the gas sensor element 10 is fixed to a measuring chamber having a capacity of about 0.2 L, NO ₂ gas is introduced into the measuring chamber at a rate of about 1.0 L / min and caused to flow to change the electric resistance of the gas sensor element. Was measured by an insulation resistance meter. The NO ₂ concentration was adjusted by mixing and diluting NO ₂ gas from a standard cylinder (24.36 ppm) at a predetermined ratio with N ₂ gas.

With the above configuration, the following can be demonstrated. FIG. 2 is a circuit diagram showing the structure of the first embodiment of the present invention.
FIG. 5 is a diagram showing a change in electric resistance of a gas sensor element due to pmNO ₂ , in which electric resistance is shown on a logarithmic scale. In this figure, the vertical axis represents electric resistance (Ω), and the horizontal axis represents time (minute). As is apparent from this figure, the electric resistance of the gas sensor element 10 greatly decreased immediately after the introduction of NO ₂ , and thereafter gradually approached a constant rate.

Next, the same measurement was performed by changing the NO ₂ concentration. FIG. 3 shows the result of measuring the rate of change (that is, the slope of the curve in FIG. 2) at which the electric resistance becomes 1/10 with respect to the change in the electric resistance (initial resistance) immediately after the introduction of NO ₂ . FIG. 3 is a diagram showing the change speed of the electric resistance immediately after the introduction of NO _{2 according} to the first embodiment of the present invention. In this figure, the vertical axis indicates the resistance change rate (/ min), and the horizontal axis indicates the NO ₂ concentration (ppm).

[0021] (see line indicated by ●) As is apparent from this figure, the rate of change of electrical resistance immediately after NO ₂ introduction, which became larger in proportion to the NO ₂ concentration. On the other hand, the rate of change in the latter period (that is, the slope of the curve in FIG. 2) is NO ₂
It was constant irrespective of the concentration (see the line marked with ▲). This relationship was maintained regardless of the element. That is,
The same measurement was performed for 20 different gas sensor elements. As a result, the initial resistance value varied (5 × 10 ⁸ Ω to 5 × 10 ⁹ Ω), but the change rate of the electric resistance was represented by a symbol. (●, ▲).

[0022]

Second Embodiment FIG. 4 is a block diagram of an explosive stability testing apparatus according to a second embodiment of the present invention. As shown in this figure,
6 g of a double base explosive 22 as a sample was placed in a sample bottle 21, immersed in a thermostatic water bath 23, and heated at 65 ° C. And NOx generated from the double base explosive 22
, Dry air and carrier gas 2
As No. 4, the gas sensor element 10 shown in FIG. 1 was introduced into a fixed measuring container 25, and a change in electric resistance of the gas sensor element 10 was measured by an insulation resistance meter 26. The change in the electric resistance can be recorded on the recorder 27.

It should be noted that, as in the prior art, N
When exposing the gas sensor element to Ox, the gas sensor element was fixed in a sample bottle sealed with an explosive and was not sealed.
In this case, the gas sensor element 10 is introduced and flowed at the installation location because the concentration of NOx exposed to the gas sensor element 10 changes with time and the gas sensor element 10
This is to prevent the change in the electric resistance from becoming unstable.

Further, the generated NOx gas was introduced into the NOx meter 28 (manufactured by Shimadzu Corporation) consisting of commercially available NO ₂ -NO converter 28A and the NOx detector 28B using chemiluminescence simultaneously, to measure the concentration . The above measurement was performed for double base explosives having different storage periods (A, B, C: new in this order).

FIG. 5 is a diagram showing a change in electric resistance of the gas sensor element with respect to the explosive C according to the second embodiment of the present invention.
In this figure, the vertical axis indicates electric resistance (Ω), and the horizontal axis indicates time (minute). That is, FIG. 5 shows a change in electric resistance of the gas sensor element 10 shown in FIG. As is clear from this figure, the gas sensor element 10
The electrical resistance greatly decreased immediately after the introduction of NOx generated from the explosive, and then gradually approached a certain rate.

FIG. 6 shows explosive A according to a second embodiment of the present invention.
FIG. 9 is a diagram showing a change speed at which the electric resistance becomes 1/10 with respect to the electric resistance change immediately after introducing NOx generated from B and C. In this figure, the electrical resistance change rate and the vertical axis (/ min) shows a concentration of NO _x (ppm) and the horizontal axis. That is, the electric resistance is reduced to 1/1 with respect to the electric resistance change immediately after the introduction of NOx generated from the explosives A, B, and C.
The result of measuring the rate of change to zero (ie, the slope of the curve in FIG. 5) was plotted against the NOx concentration measured by the NOx meter. As is clear from this figure, the concentration of NOx generated from the explosive increases with the age of the explosive, and the rate of change in electrical resistance immediately after the introduction of NOx also increases in proportion to the NOx concentration.

On the other hand, the rate of change in the latter period (ie, the slope of the curve in FIG. 5) was constant irrespective of the explosive (ie, irrespective of the concentration of NOx generated). This relationship was maintained regardless of the gas sensor element. That is, 20
As a result of performing the same measurement for the different gas sensor elements, the initial resistance value varied, but the change rate of the electric resistance (5 × 10 ⁸ Ω to 5 × 10 ⁹ Ω) was all represented by the symbol ( ●, ▲).

Next, as a comparative example, potash iodide starch test paper for an abel test was used in place of the gas sensor element.
The discoloration rate (reciprocal of the time until discoloration appeared) was measured. FIG. 7 is a diagram showing the relationship between the color change speed immediately after NOx introduction and the electric resistance change speed of the gas sensor element according to the second embodiment of the present invention. In this figure, the vertical axis shows the color change speed (/ min), and the horizontal axis shows the electric resistance change speed (/ min).

As is clear from this figure, a good correlation is seen between them, but the discoloration rate of the test paper is
It can be seen that the electric resistance change speed of the gas sensor element is about one order of magnitude slower. In addition, the discoloration speed of the test paper varied greatly depending on the measurer. The figure also shows the standard deviation when 20 different operators performed similar measurements.

[0030]

Third Embodiment FIG. 8 is a plan view of a gas sensor element showing a third embodiment of the present invention. In the present embodiment, a comb-shaped electrode substrate similar to that shown in FIG. 1 is used, and lead phthalocyanine (manufactured by Dojin Chemical Co., Ltd.) is vacuum-deposited on the comb-shaped electrode substrate in the same manner as in the first embodiment. Sensitive membrane 3
1 was used.

Next, using the apparatus shown in FIG. 4, in the same manner as described above, NOx
The gas sensor element 30 was exposed to a gas, and the change in its electric resistance was measured. With the configuration described above, the following can be verified. The above measurement was performed for the double base explosives A, B, and C having different storage periods, as in the example of the second example. As a result, similarly to the second embodiment, the electric resistance of the gas sensor element 30 greatly decreased immediately after the introduction of NOx generated from the explosive, and thereafter gradually approached a constant rate.

FIG. 9 is a diagram showing the relationship between the NOx concentration and the resistance change speed according to the third embodiment of the present invention. In this figure, the vertical axis electric resistance change rate (/ min), the horizontal axis represents the NO _X concentration (ppm). That is, FIG.
The result of measuring the change rate at which the electric resistance becomes 1/10 with respect to the electric resistance change immediately after the introduction of NOx generated from the explosives A, B and C is measured by the NOx meter.
Plotted against concentration. As is clear from this figure, the concentration of NOx generated from the explosive is larger for the older explosive, and the rate of change of the electric resistance immediately after the introduction of NOx is higher than that of the NOx.
It increased in proportion to x concentration.

On the other hand, the rate of change in the latter period was constant irrespective of the explosive. This relationship was maintained regardless of the gas sensor element. That is, as a result of performing the same measurement for 20 different gas sensor elements, the initial resistance value varied, but the electrical resistance (10 ⁸ Ω to 10 ⁹ Ω) was observed.
Were all within the symbols (●, ▲).

[0034]

Fourth Embodiment FIG. 10 is a plan view of a gas sensor element showing a fourth embodiment of the present invention. In this embodiment, a comb-shaped electrode substrate similar to that shown in FIG. 1 is used, and a cobalt phthalocyanine (manufactured by Kanto Chemical Co.) is vacuum-deposited on the comb-shaped electrode substrate in the same manner as in the first embodiment. A gas sensor element 40 having 41 was used.

Next, by using the apparatus shown in the second embodiment (FIG. 4), the gas sensor element 40 is exposed to NOx generated from the double base explosive in the same manner as described above, and the change in the electric resistance is measured. did. With the configuration described above, the following can be verified. The same as the embodiment shown in the second embodiment (FIG. 4), the double base explosive A having a different storage period,
The above measurements were performed on B and C. As a result, similarly to the embodiment shown in FIG. 4, the electric resistance of the gas sensor element 40 greatly decreased immediately after the introduction of NOx generated from the explosive, and thereafter gradually approached a constant rate.

FIG. 11 shows a NOx according to a fourth embodiment of the present invention.
FIG. 4 is a diagram showing a relationship between the concentration of the chromium and the resistance change speed.
In this figure, the vertical axis indicates the electric resistance change rate (/ min),
The horizontal axis represents the NO _X concentration (ppm). FIG. 11 shows the result of measuring the change rate at which the electric resistance becomes 1/10 with respect to the electric resistance change immediately after the introduction of NOx generated from explosives A, B, and C, and the NOx concentration measured by the NOx meter. Plotted against As is clear from this figure,
The concentration of NOx generated from gunpowder is larger for older gunpowder,
The rate of change in electrical resistance immediately after the introduction of NOx also increased in proportion to the NOx concentration.

On the other hand, the rate of change in the latter period was constant irrespective of the explosive. This relationship was maintained regardless of the gas sensor element. That is, as a result of performing similar measurements on 20 different gas sensor elements, the initial resistance value varied, but the electrical resistance (5 × 10 ⁸ Ω to 5 × 1
( ^{9 9} Ω) were all within the symbols (●, ▲).

The present invention further has the following modes of use. In the above embodiment, the case where copper phthalocyanine, lead phthalocyanine, and cobalt phthalocyanine were used as the sensitive film was described.However, the present invention is not limited to this. A similar effect can be obtained even with metals such as zinc and magnesium.

Although the speed at which the electric resistance changes to 1/10 is used as the electric resistance change speed of the gas sensor element, the present invention is not limited to this.
A speed that changes to e may be used. Further, a container for sealing the explosive and a container for fixing the gas sensor element are separately provided. However, when exposing the gas sensor element to NOx, the same container may be used if NOx is caused to flow to the installation location of the gas sensor element by the carrier gas. May be used.

It should be noted that the present invention is not limited to the above embodiment, and various modifications can be made based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

[0041]

As described above, according to the present invention, the following effects can be obtained. (1) According to the first aspect of the present invention, a phthalocyanine is used as a sensitive film, and a gas sensor element for measuring a change in electric resistance of the sensitive film due to gas adsorption is used to detect NOx generated from an explosive to detect nitric acid. In a method for testing the stability of an ester explosive, NOx generated from the explosive is used.
Immediately after the gas sensor element is exposed to the gas sensor, the speed at which the electric resistance value of the gas sensor element changes to 1 / A (A is a real number greater than 1) is measured.

Therefore, the stability of the explosive can be quickly and accurately determined with good reproducibility. (2) According to the second aspect of the present invention, since the gas sensor element measures the change in electric resistance of the sensitive film by means of a comb-shaped electrode, the gas sensor element has a small and simple structure and is quickly and accurately. In addition, the stability of the explosive can be determined with good reproducibility.

(3) According to the third aspect of the present invention, when exposing the gas sensor element to the NOx,
Since x is introduced and flowed into the installation location of the gas sensor element by the carrier gas, the concentration of NOx exposed to the gas sensor element changes with time, and the electric resistance change of the gas sensor element becomes unstable. Can be avoided.

[Brief description of the drawings]

FIG. 1 is a plan view of a gas sensor element showing a first embodiment of the present invention.

FIG. 2 shows 0.3 ppm NO _{2 according} to a first embodiment of the present invention.
FIG. 4 is a diagram showing a change in electric resistance of the gas sensor element due to the electric resistance on a logarithmic scale.

FIG. 3 is a diagram showing a change speed of electric resistance immediately after NO _{2 is} introduced according to the first embodiment of the present invention.

FIG. 4 is a configuration diagram of an explosive stability testing apparatus according to a second embodiment of the present invention.

FIG. 5 is a diagram showing a change in electric resistance of a gas sensor element with respect to an explosive C according to a second embodiment of the present invention.

FIG. 6 is a diagram showing a change speed at which the electric resistance becomes 1/10 with respect to the electric resistance change immediately after introducing NOx generated from explosives A, B, and C according to the second embodiment of the present invention. .

FIG. 7 is a diagram showing the relationship between the color change speed immediately after NOx introduction and the electric resistance change speed of the gas sensor element according to the second embodiment of the present invention.

FIG. 8 is a plan view of a gas sensor element showing a third embodiment of the present invention.

FIG. 9 is a diagram showing a relationship between a NOx concentration and a resistance change speed according to a third embodiment of the present invention.

FIG. 10 is a plan view of a gas sensor element showing a fourth embodiment of the present invention.

FIG. 11 is a diagram showing a relationship between a NOx concentration and a resistance change speed according to a fourth embodiment of the present invention.

[Explanation of symbols]

10, 30, 40 Gas sensor element 11 Glass substrate 12 Comb electrode connection terminal 13 Comb electrode 14 Copper phthalocyanine sensitive film 21 Sample bottle 22 Double base explosive (sample) 23 Constant temperature water tank 24 Carrier gas 25 Measurement container 26 Insulation resistance meter 27 Recording total 28 NOx analyzer 28A NO ₂ -NO converter 28B NOx detector 31 lead phthalocyanine sensitive film 41 cobalt phthalocyanine sensitive film

Continuing from the front page (72) Inventor Katsuaki Kaibe 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd. (72) Inventor Toyosaku Sato 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric (72) Kunihiko Nono 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd. (56) Reference JP-A-8-220039 (JP, A) (58) ) Surveyed field (Int.Cl. ⁶ , DB name) G01N 27/12 G01N 33/22

Claims (3)

(57) [Claims] 1. Test the stability of nitrate ester explosives by using phthalocyanines as a sensitive film and detecting NOx generated from the explosive by using a gas sensor element for measuring a change in electric resistance of the sensitive film due to gas adsorption. And measuring a speed at which the electric resistance value of the gas sensor element changes to 1 / A (A is a real number greater than 1) immediately after exposing the gas sensor element to NOx generated from the explosive. Stability test method. 2. The explosive stability test method according to claim 1, wherein the gas sensor element measures a change in electric resistance of the sensitive film by means of a comb-shaped electrode. 3. The explosive according to claim 1, wherein when exposing the gas sensor element to the NOx, the NOx is introduced and flown into the gas sensor element installation location by a carrier gas. Stability test method.