JPH0151474B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a water-in-oil type (hereinafter referred to as W/O type) emulsion explosive. W/O type emulsion explosive has US patent no.
It was first published in No. 3161551, but its research has progressed rapidly recently, and has been published in Japanese Patent Application Publication Nos. 54-126714, 110308-1980, 95699-1980, and 1982-
100192, JP-A-56-129694, JP-A-58-125681,
Many improved inventions have been made such as JP 58-190890, U.S. Patent No. 4110134, U.S. Patent No. 4218272, U.S. Patent No. 4310364, and U.S. Patent No. 4371408, and it has already been commercially available in Japan since around 1988. It is. The W/O type emulsion explosives according to these inventions are used in a wide variety of applications, ranging from highly sensitive detonator-detonated explosives to low-sensitivity booster-detonated explosives. W/O emulsion explosives contain water in their composition, making them much safer than conventional dynamite, and because they form a fine emulsion, their performance is comparable to that of conventional slurry explosives (water gel). It has been replaced with conventional slurry explosives (water gel) or dynamite because it is dramatically improved compared to conventional slurry explosives (water gel) and can be packaged in paper, which was difficult with conventional slurry explosives (water gel). It is expected that it will be widely used in the market. However, although both the conventional slurry explosive (water gel) and the W/O type emulsion explosive developed by these inventions are significantly safer to handle than dynamite, which is the mainstay of industrial explosives, they are difficult to blast. In some cases, the drawback was that there were many non-explosions and residues. Unexploded or residual particles during blasting, which is the process of crushing rocks, etc., not only means that the intended purpose cannot be achieved, but also that the explosives used do not emit the calculated results, resulting in a large loss in terms of cost. This is a fatal flaw for it to be widely used as a replacement for dynamite. Therefore, it has been a major challenge for those skilled in the art how to reduce the amount of unexploded residual W/O emulsion explosives. In order to solve this problem, the present inventors conducted intensive research and found that unexploded residual W/O type emulsion explosives mainly occur when a blasting method called stage blasting is carried out. It was discovered that this occurs in emulsion explosives. More specifically, in stage-by-stage blasting, the shock wave generated by the blasting of the first stage (in other words, the explosion of the first stage explosive) affects the charge of the second stage, and as a result, the W/O emulsion explosive of the second stage It was discovered that the explosions are more likely to remain unexploded. In other words, it was discovered that the shock wave from the blasting of the first stage compresses and destroys the microscopic hollow bodies contained in the W/O type emulsion explosive of the second stage, resulting in what is called a dead pressure state as those skilled in the art would call it, resulting in non-explosion and residue. be. In order to solve this problem, it is possible to increase the strength of the microscopic hollow spheres contained in the W/O emulsion explosive, but the detonation and conductivity of the W/O emulsion explosive cannot be guaranteed. The so-called sensitivity is generally maintained by the microscopic hollow spheres contained therein, and therefore, simply increasing the strength of the microscopic hollow spheres usually significantly reduces the sensitivity, or performance, of the explosive. can be,
While maintaining sensitivity, i.e. performance, and W/O
It has been extremely difficult to impart impact resistance to type emulsion explosives. In order to solve this problem, the present inventors conducted long-term research and found that microscopic hollow spheres contained in W/O emulsion explosives were measured using the ASTM D3102-72 method and in units of psi (1b/in ² ). If glass microspheres are used in which the ratio r (S/d) between the expressed 10% breaking strength S and the specific gravity d representing the average particle is between 3,000 and 20,000, the sensitivity of the W/O emulsion can be improved. It has been discovered that the impact resistance of W/O emulsion explosives can be significantly improved without degrading performance, and there is almost no misfire or residue. Table 1 shows the true specific gravity d of the 10% breaking strength S of currently commercially available glass micro hollow spheres and the glass micro hollow spheres trial-produced by the present inventors, and the ratio r between the two.

[Table] The present inventors have found that sensitivity and performance can be improved by preparing a W/O emulsion explosive using glass micro hollow spheres with r values in the range of 3000 to 20000 as shown in Table 1. Conventional W/
It has been found that the occurrence of unexploded and residual materials, which could not be improved with O-type emulsion explosives, can be extremely reduced. Conventional W/O type emulsion explosives do not take into consideration the matters mentioned in the present invention, and are used only for the purpose of improving the sensitivity of the explosive. It was customary to use glass microscopic hollow spheres with a value of 3000 or less. For example, in JP-A-54-126714, E22X with r=2270
(Product name), in JP-A-54-110308, r=1670.
B15/250, Q- of r=1250 in JP-A-55-95699
cell200, r=2270 in JP-A-55-167198
E22X, B28/ of r=2680 in JP-A-56-100192
750, B28/ of r=2680 in JP-A-56-109890
750, B28/ of r=2680 in JP-A-56-129694
750, C15/ of r=1670 in JP-A-58-125681
250, B15/ of r=1670 in JP-A-58-190890
250, in U.S. Pat. No. 4,110,134, B15/ with r=1670
250 and r=1250 Qcell200 in U.S. Pat. No. 4,218,272, B15/250 with r=1670 in U.S. Pat. B15/
250 were used, and it can be seen from these examples that no consideration was given to using glass micro hollow spheres with r = 3000 to 20000 as described in the present invention. It's obvious. The glass micro hollow spheres used in the W/O emulsion explosive of the present invention are made of silicon dioxide (SiO ₂ ).
The main component is alkali metal oxides such as Na ₂ O, and other alkaline earth metal oxides such as boric acid.The average particle size d is
10 to 500μ, preferably 30 to 200μ is used. Also, the cell thickness is 0.1 to 10μ, preferably
Those in the range of 0.3 to 5μ are used. In the present invention, glass micro hollow spheres having a ratio r of 10% breaking strength to average particle specific gravity of 3,000 to 20,000 can be used, but preferably r is 5,000 to 20,000.
15,000 are used. The amount of glass micro hollow spheres used in the W/O type emulsion explosive of the present invention varies over a wide range depending on the use of the explosive, and also depends on the specific gravity of the hollow spheres, so it cannot be determined with certainty. Usually, the amount used is such that the specific gravity of the explosive is 1.40 g/cc or less, and preferably 1.3 g/cc or less. The oxidizing agent aqueous solution used in the present invention includes ammonium nitrate, alkali metal nitrates, alkaline earth metal nitrates, alkali metal chlorates, alkaline earth metal chlorates, alkali metal perchlorates, and alkaline earth metal nitrates. Chlorates and ammonium perchlorate are dissolved in water, either alone or as a mixture. In addition, water-soluble amine nitrates such as monomethylamine nitrate, hydrazine nitrate, dimethylamine dinitrate, water-soluble alkanolamine nitrates such as methanolamine nitrate, ethanolamine nitrate, etc. Ethylene glycol mononitrate can be used as a co-desensitizing agent. The water content in the oxidizing agent aqueous solution is preferably used within a range where the crystal precipitation temperature of the oxidizing agent aqueous solution is 30 to 90°C, and usually 5% to 90°C.
~40% by weight, preferably 7-30% by weight
is used. In the oxidizing agent aqueous solution, a water-soluble organic solvent such as methyl alcohol, ethyl alcohol, formamide, ethylene glycol, or glycerin can be used as an auxiliary solvent in order to lower the crystal precipitation temperature. In the present invention, the oxidizing agent aqueous solution is 50%
Used in the range of ~90% by weight. Oils used in the present invention include petroleum oils such as light oil, kerosene, mineral oil, lubricating oil, and heavy oil, petroleum waxes such as paraffin wax and microcrystalline wax, and other hydrophobic waxes. One or a mixture of two or more of vegetable oil, vegetable wax, animal oil, and animal wax may be used. In addition, the above-mentioned oils include epoxy resin, unsaturated polyester resin, polybutene,
Polyisobutylene, petroleum resin, butadiene resin,
Oils modified by blending resins such as ethylene vinyl acetate copolymer and polyethylene resin can also be used. The amount of oil used in the present invention ranges from 1 to 10% by weight, preferably from 2 to 8% by weight. The emulsifier used in the present invention is generally W/
The emulsifier used to form the O-type emulsion is selected. For example, alkali metal salts or ammonium salts of stearic acid, polyoxyethylene alkyl ethers, fatty acid glycerides, polyethylene glycol fatty acid esters, oxadoline derivatives, sorbitan fatty acid esters, etc. may be used alone or in combination.
Used as a mixture of more than one species. The emulsifier used in the present invention can be used in a range of 0.5 to 7.0% by weight. Depending on the purpose, the W/O emulsion explosive according to the present invention may be made of hollow spheres other than glass, such as shirasu balloons or perlite, or explosive substances such as TNT or pentrites, or chemical blowing agents, aluminum powder, or magnesium. It is also possible to add metal powders such as powder, or powdered organic substances such as wood flour and starch. The present invention will be described in detail below with reference to Examples. Example 1 Wax Rex 140 (Mobil Oil Company) 2.5
Weight% and polyisobutylene (manufactured by Etsuo Chemical Co., Ltd.,
Product name: Vistanetx LMMS) 1.0% by weight at 90℃
A W/O type emulsion was prepared by heating and dissolving the mixture and adding more than 2.8% by weight of sorbitan monooleate as an emulsifier. For 100 parts of this emulsion, the ratio r of 10% breaking strength (S) and average particle specific gravity (d)
4.0 parts by weight of glass micro hollow bodies (A20/1000) manufactured by 3M Company, USA having a particle diameter of 5000 were added and mixed with stirring to obtain a W/O type emulsion explosive having a specific gravity of 1.12. Example 2 7.8 parts of glass micro hollow bodies (A32/2500) manufactured by 3M Company in the United States having a ratio r of 10% breaking strength to average particle specific gravity of 7810 were added to 100 parts of an emulsion prepared by the same method and composition as in Example 1. was added and mixed with stirring to obtain a W/O emulsion explosive having a specific gravity of 1.12. Example 3 8.8 parts of glass micro hollow bodies (B37/2000) manufactured by 3M Company in the United States having a ratio r of 10% breaking strength to average particle specific gravity of 5410 were added to 100 parts of an emulsion prepared by the same method and composition as in Example 1. Add and stir to mix, and check the specific gravity.
A W/O type emulsion explosive of 1.12 was obtained. Example 4 8.2 parts of glass micro hollow sphere sample 2 (listed in Table 1) having a ratio r of 10% breaking strength to average particle specific gravity of 11430 was added to 100 parts of an emulsion prepared by the same method and composition as in Example 1. Add, stir to mix, and check the specific gravity.
A W/O type emulsion explosive of 1.12 was obtained. Comparative Example 1 3.0 parts of glass micro hollow spheres (B15/250) manufactured by 3M Company in the United States having a ratio r of 10% breaking strength and average particle specific gravity of 1670 were added to 100 parts of an emulsion prepared by the same method and composition as in Example 1. was added and mixed with stirring to obtain a W/O emulsion explosive having a specific gravity of 1.12. Comparative Example 2 6.5 parts of glass micro hollow spheres (B28/750) manufactured by 3M Company in the United States and having a ratio r of 10% breaking strength to average particle specific gravity of 2680 were added to 100 parts of an emulsion prepared by the same method and composition as in Example 1. was added and mixed with stirring to obtain a W/O emulsion explosive having a specific gravity of 1.12. Comparative Example 3 Glass micro hollow sphere sample 3 manufactured by Central Glass Co., Ltd. with a ratio r of 10% breaking strength and average particle specific gravity of 21250 was added to 100 parts of an emulsion prepared by the same method and composition as in Example 1 (listed in Table 1). Add 10.0 parts,
A W/O emulsion explosive with a specific gravity of 1.12 was obtained. The W/O emulsion explosives of Examples 1 to 4 and Comparative Examples 1 to 3 were subjected to two types of tests: the explosive sensitivity test method (A) and the explosive impact resistance test method (B), which are detailed below. was carried out. Sensitivity test method A: Pack the W/O type emulsion explosive to be tested into a paper tube with a diameter of 30 mm to make a 100 g explosive cartridge. The medicine packet is cooled to the desired temperature overnight using a suitable cooling device. The test explosive package that has been sufficiently cooled to a constant temperature is taken out and detonated using a commercially available No. 6 detonator to see if the test explosive package explodes. Perform three tests at the same temperature, and if all three explosions occur, repeat the test at a lower temperature. The experiment was conducted in this way, and the lowest temperature at which it exploded (limit detonation temperature) was reached in all three tests.
seek. The lower the temperature, the more sensitive the test explosive is, and the higher the temperature, the less sensitive it is. Impact test method B The underwater impact test described in the paper published in Journal of Industrial Explosives Association, Vol. 43, No. 5, 1982, pages 317 to 312 was applied to the impact test. This test is a method suitable for investigating the pressure-resistant properties of the explosive in the first stage of stage blasting, and the inventors used W/O of Example 1 as the exciter.
A type emulsion explosive (30 mm diameter x 100 g) equipped with a No. 6 instantaneous electric detonator was used. In addition, a test explosive package (30 mm diameter x 100 g) equipped with a DS-2 stage electric detonator that detonated with a delay of 250 milliseconds was used as the explosive charge. A donor agent (exciter) and an acceptor agent (detonator) are placed in water at a depth of 1 meter, separated by a predetermined distance, as described in the paper.
energize the donor and acceptor electric detonators;
Determine whether the acceptor completely explodes without being affected by the shock wave from the donor. The test is conducted three times at the same distance, and the minimum distance at which the acceptor detonates completely three times is determined as the critical detonation distance. The shorter this distance, the more resistant it is to donor impact. In other words, the impact resistance is strong, or the explosive is difficult to reach dead pressure. On the other hand, the longer the distance, the less resistant the explosive is to impact from the donor, in other words, the impact resistance is weak or the explosive is susceptible to dead pressure. Table 2 shows the test results of Examples 1 to 4 and Comparative Examples 1 to 3.
summarized in.

[Table] Considering the use of W/O type emulsion explosives in winter, the limit detonation temperature is at least -5℃.
It is necessary that the following is true. Considering this point, Comparative Example 3, in which the ratio r of the 10% breaking strength to the average particle specific gravity is extremely large, is a glass hollow sphere that is clearly lacking in practicality. Examples 1 to 4 and Comparative Examples 1 to 2 have sensitivity sufficient to withstand use in winter, but there is a limit at which the risk of unexploded residue occurring in all types of rocks is extremely low in actual stage blasting. According to research by the present inventors, the explosion distance is 1.0 m, and Comparative Examples 1 and 2 have a drawback in practicality in this respect. On the other hand, the critical explosion distance shown in Examples 1 to 4 is 1.0 m or less. It can be seen that the impact resistance is clearly improved compared to the comparative example. In addition, the limit detonation temperature is low, so there is no problem with its practicality in winter. Example 5 3.5% by weight of liquid paraffin was dissolved by heating at 90°C,
To this, 14.1% by weight of water, 70.0% by weight of ammonium nitrate, 5.0% by weight of sodium nitrate, and 4.6% by weight of sodium perchlorate were added in advance as an oxidizing agent aqueous solution.
A W/O emulsion was prepared by heating and dissolving the mixture at 90° C. and adding 2.8% by weight of polyglycerin linoleic acid ester as an emulsifier. To 100 parts of this emulsion, 3.8 parts of glass micro hollow spheres (A32/2500) manufactured by 3M Company in the United States having a ratio r of 10% breaking strength to average particle specific gravity of 7810 were added and mixed by stirring.
A W/O type emulsion explosive with a specific gravity of 1.25 was obtained. Example 6 4.0 parts of glass micro hollow spheres (D32/4500) manufactured by 3M Company in the United States having a ratio r of 10% breaking strength and average particle specific gravity of 14060 were added to 100 parts of an emulsion prepared by the same method and composition as in Example 5. Add, stir to mix, and check the specific gravity.
A W/O type emulsion explosive of 1.25 was obtained. Example 7 To 100 parts of an emulsion prepared in the same manner and with the same composition as in Example 5, glass micro hollow sphere sample 1 manufactured by Central Glass Co., Ltd. with a ratio r of 10% breaking strength and average particle specific gravity of 6670 (listed in Table 1) was added. 3.2 parts of 3.2 parts of 1.0% of the mixture was added and mixed with stirring to obtain a W/O type emulsion explosive with a specific gravity of 1.25. Comparative Example 4 To 100 parts of an emulsion prepared in the same manner and with the same composition as in Example 5, glass micro hollow spheres Qcell 200 manufactured by Freidelphi Quartz Co., Ltd. in the United States having a ratio r of 10% breaking strength and average particle specific gravity of 1250 were added by weight of 2.0 parts. %
In addition, the mixture was stirred and mixed to obtain a W/O type emulsion explosive having a specific gravity of 1.25. Comparative Example 5 To 100 parts of an emulsion prepared in the same manner and with the same composition as in Example 5, 5.5 parts of glass micro hollow sphere sample 3 manufactured by Central Glass Co., Ltd. with a ratio r of 10% breaking strength and average particle specific gravity of 21250 was added and stirred. Mix, W/
An O-type emulsion explosive was obtained. The specific gravity of the finished explosive is
It was 1.23. The W/O emulsion explosives prepared in Examples 5 to 7 and Comparative Examples 4 to 5 were tested using the sensitivity test method (C) and the impact test method (D), which are detailed below. Sensitivity Test Method C The W/O type emulsion explosive to be tested was filled into a synthetic resin film tube with a diameter of 40 mm to form an explosive cartridge weighing 500 g. The capsule is cooled in the same manner as Sensitivity Test Method A. The test cartridge, which has been sufficiently cooled to a constant temperature, is detonated with 20 gr of pentolite, an explosive consisting of 50:50 TNT/PETN, and the critical explosion temperature is determined in the same manner as sensitivity test method A. Impact resistance test method D The principle is the same as the impact resistance test method B described above, but a sensitivity test method is applied to the detonation part of the acceptor charge (30 mm diameter, 100 g), which is the cartridge of the W/O emulsion explosive to be tested. TNT/PETN used in C: 50:50
Attach 20g of explosives (pentolite) and place it inside this
The method is to install a DS-2 stage electric detonator.
Other than that, the critical explosion distance is determined using exactly the same method as impact resistance test method B. The critical detonation temperatures and critical detonation distances of the W/O emulsion explosives prepared in Examples 5 to 7 and Comparative Examples 4 to 5 were determined according to the above-mentioned test method, and are listed in Table 3.

[Table] Regarding the W/O type emulsion explosives detonated by pentolite in Examples 5 to 7 and Comparative Examples 4 to 5, implementation according to the present invention is possible if both detonation sensitivity and impact resistance in winter are considered. It is clear that the example is significantly superior to the comparative example.

Claims (1)

[Claims] 1. In a water-in-oil emulsion explosive consisting of an oxidizing agent aqueous solution, an oil, an emulsifier, and micro hollow spheres, the micro hollow spheres account for 10% expressed in psi [lb/in2].
Ratio r (S/d) of breaking strength S and average particle specific gravity d
A water-in-oil emulsion explosive characterized by comprising glass microscopic hollow spheres having a particle diameter in the range of 3,000 to 20,000.