JPH0147440B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a water-in-oil emulsion explosive (hereinafter abbreviated as W/O emulsion explosive) that does not contain explosives or auxiliary sensitive substances such as ammonium perchlorate or sodium chlorate, Microscopic hollow spheres made of unfoamed thermally expandable resin are mixed uniformly during or immediately after the formation of a W/O emulsion as microscopic hollow spheres as a regulating agent, and are foamed and expanded to the desired tentative specific gravity of the explosive. The method for producing this W/O emulsion explosive is characterized in that a W/O emulsion is produced using conventionally known inorganic micro hollow spheres or micro hollow spheres made of a thermally expandable resin that has already been foamed and expanded. Compared to the manufacturing method of W/O type emulsion explosives, which are mixed after being formed, it is easy to manufacture, small diameter (25
The present invention relates to a method for producing a W/O emulsion explosive which has significantly improved stability over time of detonation sensitivity (mm) and detonation sensitivity at low temperatures and dead pressure resistance. W/O that does not contain explosives and auxiliary sensitive substances such as ammonium perchlorate or sodium chlorate.
Type emulsion explosives have been studied for a long time, and several patents have been disclosed. For example, according to US Pat. No. 4,110,134, glass micro hollow spheres with an apparent specific gravity of 0.15 are mixed as inorganic micro hollow spheres after a W/O type emulsion is formed, and a drug with a diameter of about 1.25 inches (31.8 mm) is prepared. It is stated that 18 to 24 hours after manufacture, it can be completely detonated with a No. 6 detonator to a maximum tentative specific gravity of 1.25 (drug temperature 21.1°C to 26.7°C). Also, in the above specification,
Saran micro hollow spheres made of a thermally expandable resin that has already been expanded and expanded and are sold by the Dow Chemical Company and have a diameter of 30 microns and an apparent specific gravity of approximately 0.032 are used by mixing them after forming a W/O emulsion. It is also stated that this is possible. Also, according to US Pat. No. 4,149,917,
The tentative specific gravity was adjusted to 0.95 using microbubbles without containing any microscopic hollow spheres, and with a diameter of 1.25 inches (31.8mm), it was completely detonated with a No. 6 detonator even after two months had passed since manufacture (drug temperature 21.1℃). ) It is stated that even after 8 months, a No. 8 detonator will cause a complete explosion (chemical temperature 21.1℃). or,
According to JP-A-55-75993, JP-A No. 55-75994, and JP-A No. 55-75995, micro hollow spheres made of inorganic micro hollow spheres and thermally expandable resin that has already been foamed and expanded include glass and shirasu micro hollow spheres. A W/O type emulsion explosive composition in which spheres and phenolic resin micro hollow spheres were mixed after forming a W/O type emulsion was subjected to temperature cycles (0°C for 4 hours and 40°C for 4 hours) without adding explosives or auxiliary sensitive substances. Even after 30 cycles (one cycle per 7 hours), the bomb exploded completely with a No. 6 detonator at -10°C to 20°C. Furthermore, according to an example in JP-A No. 56-100192, 2.5 to 6.0% of Saran micro hollow spheres, which are sold by Dow Chemical Company as micro hollow spheres made of a thermally expandable resin that has already been expanded and expanded, are mixed with W. It is stated that a W/O type emulsion explosive composition mixed after forming a /O type emulsion can be completely detonated with a No. 6 detonator even after 10 months with a tentative specific gravity of the explosive of 0.95 to 1.08. However, as described in the above-mentioned U.S. patent specifications and published patent publications, a W/O emulsion explosive composition is produced by mixing micro hollow spheres made of a thermally expandable resin that has already been foamed and expanded after forming a W/O emulsion. Regarding the method, the micro hollow spheres made of the thermally expandable resin can be made by foaming, but depending on the degree of expansion,
The apparent specific gravity is around 0.03 to 0.20, so it is extremely bulky, and the difference in specific gravity from normal W/O emulsions (1.20 to 1.60) is too large, making it difficult to mix uniformly in a short time, making it difficult to manufacture. It's bad. Furthermore, if the stirring efficiency is increased or the stirring time is lengthened in order to achieve uniform mixing, the micro hollow spheres made of the thermally expandable resin that have already been foamed and expanded or the ideally formed W/O emulsion will be destroyed. Therefore, the inventors conducted a temperature cycle test that well reflected the aging of detonation sensitivity at room temperature (0°C to 30°C) at low temperatures with a small diameter (25 mm), as well as detonation waves from adjacent holes, combustion gas, etc. According to the dead pressure resistance test, which shows the resistance to the non-explosion phenomenon (commonly called the "dead pressure phenomenon"), which is based on the destruction of micro hollow spheres and W/O type emulsions due to the action of , which has improved manufacturability and a small diameter (25
There has been a desire for a W/O emulsion with excellent stability over time of detonation sensitivity in mm) and dead pressure resistance of a W/O type emulsion. Therefore, as a result of long-term intensive research in order to solve the above-mentioned problems, the inventors of the present invention have developed a known W/O emulsion in which micro hollow spheres made of a thermally expandable resin after foaming and expansion are mixed after forming a W/O type emulsion. Compared to the method for producing /O-type emulsion explosives, the desired method can be achieved by mixing microscopic hollow spheres made of a thermally expandable resin before foaming during or immediately after forming a W/O-type emulsion, and adjusting the ambient temperature and action time. The manufacturing method in which the explosive is expanded to a temporary specific gravity (0.8 to 1.35) is not only easy to manufacture, but also has stable detonation sensitivity over time at small diameters (25 mm) and low temperatures. The inventors have now completed the present invention by discovering that the properties and dead pressure resistance are significantly improved. That is, the method for producing a W/O emulsion explosive of the present invention includes (a) preparing an oxidizing agent aqueous solution containing ammonium nitrate as a main component, and (b) preparing a combustible agent mixture consisting of an emulsifier and an oil. (c) emulsifying and mixing the oxidizing agent aqueous solution and the flammable agent mixture to form a W/O emulsion; and (d) mixing micro hollow spheres into the water-in-oil emulsion. , (e) A method for producing a W/O emulsion explosive, which comprises a subsequent packaging step,
W/ unfoamed thermally expandable resin as micro hollow spheres
The tentative specific gravity of the desired explosive (0.80
It is characterized by foaming and expanding up to 1.35). A more detailed explanation of the method for producing the W/O emulsion explosive of the present invention is as follows, for example. That is, ammonium nitrate or a mixture of ammonium nitrate and other inorganic oxide salts is heated at about 90°C to
Obtain an oxidizing agent aqueous solution dissolved in water at 150°C. On the other hand, a combustible mixture is obtained by melt-mixing a known emulsifier and oil at 90°C to 150°C. Next, first put the combustible mixture in a heat-insulating container with a certain volume, and gradually add the oxidizing agent aqueous solution, using a commonly used propeller blade stirrer, at about 1600 rpm for about 2 to 3 minutes.
Mix and stir for 3 minutes to obtain a W/O emulsion at a temperature of about 90°C to 150°C. Next, micro hollow spheres made of unfoamed thermally expandable resin are mixed into the above W/O emulsion and stirred for an additional 2 to 3 minutes at about 1600 rpm to form a W/O emulsion at about 85°C to 140°C. Get explosives. Thereafter, by adjusting the ambient temperature and action time, the micro hollow spheres made of thermally expandable resin are foamed to an apparent specific gravity of 0.01 to 0.50, and the tentative specific gravity of the W/O emulsion explosive is adjusted to 0.8 to 0.50.
1.35 and then packaging it using a known packaging method. Why is it that mixing micro hollow spheres made of a thermally expandable resin that has already been foamed and expanded after forming a W/O type emulsion is better than mixing micro hollow spheres made of an unfoamed thermally expandable resin during or during the formation of a W/O type emulsion? A manufacturing method in which the explosives are immediately mixed and expanded to reach the desired tentative specific gravity of the explosive is not only easier to manufacture, but also significantly improves the stability over time of detonation sensitivity and dead pressure resistance at small diameters (25 mm) and low temperatures. can be considered as follows. In other words, micro hollow spheres made of thermally expandable resin that have already been foamed and expanded have an apparent specific gravity of about 0.03 to 0.20, depending on the degree of foaming and expansion, so they are extremely bulky and easily scattered, so they cannot be stored or stored. It is difficult and expensive to transport, and the difference in specific gravity (1.20 to 1.60) from ordinary W/O emulsions is too large, making it difficult to mix uniformly in a short time. Also, if you try to improve the stirring efficiency or lengthen the stirring time in order to mix uniformly, the micro hollow spheres made of the thermally expandable resin that has already expanded and expanded, and the ideally formed W/O emulsion morphology will be destroyed. Therefore, the various performances mentioned above are considered to be deteriorated. On the other hand, micro hollow spheres made of unfoamed thermally expandable resin have an apparent specific gravity of 1.00 to 1.50, so their specific gravity with respect to W/O emulsions is small, and their bulk and scattering are small. In order to uniformly mix the O-type emulsion, there is no need to improve the stirring efficiency or to lengthen the stirring time, so uniform mixing can be easily achieved in a short time. Therefore, there is extremely little destruction of the micro hollow spheres made of thermally expandable resin and the W/O type emulsion that has already been ideally formed, which not only improves manufacturability but also stabilizes detonation sensitivity over time at small diameters (25 mm) and low temperatures. It is considered that the properties and dead pressure resistance have been significantly improved. The oxidizing agent aqueous solution used in the present invention contains ammonium nitrate as a main component and contains other inorganic oxidizing acid salts as necessary. Here, the other inorganic oxide salts are, for example, nitrates of alkali metals or alkaline earth metals such as sodium nitrate and calcium nitrate. In addition, auxiliary sensitizers such as perchlorates and chlorates of alkali metals or alkaline earth metals, or sensitizers such as monomethylamine nitrate are not essential components in terms of stability over time of detonation sensitivity and dead pressure resistance. There is no problem even if it is mixed. These inorganic oxidized acid salts may be used alone or as a mixture of two or more. The blending amount of ammonium nitrate is generally 48% to 94.7% (by weight, the same applies hereinafter) of the total amount, and if necessary, other inorganic oxide salts may be included at 40% or less of the total amount of inorganic oxide salts including ammonium nitrate. It's okay. If the amount of ammonium nitrate is less than the lower limit, the oxygen balance (the relationship between excess and deficiency of oxygen between the oxidizing agent and the combustible agent) will be too poor (oxygen deficiency), resulting in poor explosiveness and aftergas. If the upper limit is exceeded, the minimum dissolution temperature of ammonium nitrate in water becomes too high, resulting in poor productivity, and the explosive reactivity of ammonium nitrate becomes poor, resulting in poor detonation sensitivity. Regarding the other inorganic oxide salts mentioned above, by adding a small amount, the amount of oxygen supplied can be increased and the minimum dissolution temperature in water can be lowered, so explosiveness and manufacturability can be improved, but the amount exceeds 40%. This increases the amount of solid residue after the explosion, resulting in lower power and disadvantages in terms of economy. Note that the amount of water used in the oxidizing agent aqueous solution is, in principle, 5% to 25%. If it is less than 5%, the minimum melting temperature of ammonium nitrate or ammonium nitrate and other inorganic oxide salts becomes too high, resulting in poor productivity and poor detonation sensitivity due to poor explosive reactivity. If it exceeds 25%, the minimum melting temperature of ammonium nitrate or ammonium nitrate and other inorganic oxide salts will be lowered, which will improve productivity, but the amount of gas produced after the explosion, amount of heat, etc. will be reduced, resulting in poor detonation sensitivity.
Power is low. The oils used in the present invention are, for example, fuel oils, waxes, etc., and the fuel oils are hydrocarbons, such as paraffinic hydrocarbons, olefinic hydrocarbons, naphthenic hydrocarbons, aromatic hydrocarbons, saturated or unsaturated. Hydrocarbons, petroleum, refined mineral oils, lubricants, liquid paraffin, etc. and hydrocarbon derivatives, such as nitrohydrocarbons. Waxes include microcrystalline waxes derived from petroleum, petrolatum, paraffin waxes, mineral waxes such as montan wax and ozokerite, animal waxes such as whale wax, and insect waxes such as beeswax. It is. These oils may be used alone or as a mixture of two or more. Further, the amount of oil blended is generally 0.1% to 10%. If the oil content is less than 0.1%, the stability of the W/O emulsion explosive composition will be poor, and if it exceeds 10%, the oxygen balance will be too poor, resulting in poor explosiveness and aftergassing. The emulsifier used in the present invention is not particularly limited, and includes all conventionally known emulsifiers that form W/O emulsions. For example, sorbitan fatty acid esters, glycerin fatty acid esters, polyoxyalkylene fatty acid esters, oxazoline derivatives, imidazoline derivatives,
These include phosphoric acid esters, alkali metal salts or alkaline earth metal salts of fatty acids, primary, secondary, and tertiary amines, or nitrates or acetates of primary, secondary, and tertiary amines. These emulsifiers may be used alone or as a mixture of two or more. The amount of emulsifier added is generally 0.1% to 7%. Preferably 0.5% to 4
%. If these various emulsifiers are less than 0.1%,
The W/O type emulsion explosive composition has poor detonation sensitivity over time and dead pressure resistance at small diameters and low temperatures, and when it exceeds 7%, the oxygen balance deteriorates, resulting in poor explosiveness and aftergassing, resulting in poor economic efficiency. disadvantageous in terms of The micro hollow spheres made of the thermally expandable resin used in the present invention have a shell wall made of, for example, a copolymer of vinylidene chloride, acrylonitrile, and an acrylic ester, or a copolymer of acrylonitrile and an acrylic ester, and contain a low-boiling hydrocarbon. do. The particle size after thermal expansion after foaming expansion is 50 to 60 microns and the apparent specific gravity
It has an apparent specific gravity of 0.01 to 0.5, preferably 0.02 to 0.30. The micro hollow spheres made of these thermally expandable resins are used alone or in a mixture of two or more, and the blending ratio is 0.01 to 7% by weight of the total amount of the W/O emulsion explosive composition, preferably 0.02 to 7% by weight.
It is 5% by weight. The micro hollow spheres made of a thermally expandable resin which is a ternary copolymer of vinylidene chloride, acrylonitrile, and methacrylic acid ester are manufactured by Matsumoto Yushi, for example, under the trade names of "Micropearl F-20 and Micropearl F-30".
Co., Ltd. and the product sold by Kemanode under the trade name "Expancel" can be used. Microscopic hollow spheres made of a thermally expandable resin which is a binary copolymer of acrylonitrile and acrylic acid ester are, for example, "Micropearl F-
50, F-60'' sold by Matsumoto Yushi Co., Ltd. can be used. If the amount of these micro hollow spheres made of thermally expandable resin is less than 0.01% by weight or if the tentative specific gravity of the W/O emulsion explosive composition exceeds 1.35, the detonation sensitivity will be poor and the explosion will be difficult. The explosion speed is low and the gas after firing is poor. In addition, if the amount of micro hollow spheres made of thermally expandable resin exceeds 7% by weight or if the tentative specific gravity of the explosive composition is less than 0.8, the detonation sensitivity is good but the detonation velocity is low, resulting in low power and Or, the oxygen balance tends to become negative, resulting in poor aftergas. The micro hollow spheres made of thermally expandable resin used in the present invention are prepared by adjusting the ambient temperature to 80°C to 150°C and
Foaming expansion is completed by heating for 10 seconds to several minutes, and then by rapidly cooling to below the softening point,
It is possible to obtain micro hollow spheres made of a thermally expandable resin whose apparent specific gravity is reduced to 0.01 to 0.50. Although it depends on the heating time, if the ambient temperature is less than 80℃,
Sufficient foam expansion is not carried out, and if the temperature exceeds 150℃, the foam expansion is too rapid, causing rupture and contraction, making it difficult to adjust to the desired temporary specific gravity, resulting in poor detonation sensitivity and low detonation velocity even if it explodes. Gas is bad after a hit. Also, although it depends on the temperature, if the heating time is less than a few tens of seconds, the foaming expansion will not be sufficient, and if the heating time is longer than a few minutes, the foaming expansion will be excessive, which will easily cause breakage and shrinkage, making it impossible to adjust the tentative specific gravity to the desired value. Because there is no such problem, the same problem as above occurs. Next, the method for producing the W/O type emulsion explosive of the present invention will be specifically explained with reference to Examples and Comparative Examples. Note that all parts and percentages in each example are based on weight. Example 1 A W/O emulsion explosive having the composition shown in Table 1 was produced as follows. First, 78.36% ammonium nitrate and 4.70% sodium nitrate were added to 11.3% water and heated to obtain an oxidizing agent aqueous solution at about 100°C. On the other hand, a mixture of 1.79% sorbitan oleate monoester and 3.50% microcrystalline wax was heated and melted to obtain a combustible mixture at about 100°C. Next, first put the combustible mixture in a heat-insulating container, and while gradually adding the oxidizing agent aqueous solution, use a propeller blade stirrer to mix and stir at about 1000 rpm for 2 minutes to bring the temperature to about 95℃. I got an emulsion.
Next, “Micro Pearl
30'' (0.30%) was mixed with the above W/O emulsion and stirred for an additional 3 minutes at about 1000 rpm to obtain a W/O emulsion explosive at about 90°C. This W/O type emulsion explosive was heated to approximately 120°C for 3 minutes to approx.
After completing the foaming of the thermally expandable resin while stirring at 600 rpm, it was rapidly cooled to 40-50℃, and then
mm, length of about 170 mm, drug amount 100 gr, and packaged with viscose processed paper and pouches W/
An O-type emulsion explosive was obtained. This explosive was subjected to various performance tests. As a performance test, (a) Measurement of provisional specific gravity one day after production
(b) Keep the test drug package at 60℃ for 24 hours, then at -15℃ for 24 hours.
After conducting a forced deterioration storage test in which the temperature cycle is repeated for a certain period of time and this is considered as one cycle, the number of temperature cycles that can cause a complete detonation is determined when a detonation test is performed at -5℃ using a No. 5 detonator. , the number of such cycles is estimated as the number of months of storage for complete detonation when stored at room temperature (0 to 30°C) (estimated based on the experimental confirmation that one temperature cycle is equivalent to approximately one month when stored at room temperature) (c) provisional specific gravity measurement during the detonation test described in (b) above, and (d) drug packaging wrapped in viscose-treated paper (drug amount
100g) and 50gr dynamite are suspended at a certain distance, and 1 second after the 50gr dynamite is fully detonated, the test drug is detonated, and the maximum underwater pressure (Kg/cm ² ) for complete detonation is determined from the minimum distance for complete detonation. A converted dead pressure resistance test was conducted. The results are shown in Table 1. Examples 2 to 3 A W/O emulsion explosive having a composition as shown in Table 1 was used instead of "Micropearl F-30" which is a microscopic hollow sphere made of a thermally expandable resin in Example 1. -50” and “Expancel”
It was manufactured according to Example 1 using the formulation compositions of Examples 2 and 3 shown in Table 1, except that . Example 1 These W/O type emulsion explosives
The product was packaged in the same manner as the product and tested on the same items. The results are shown in Table 1. Examples 4 to 6 W/O type emulsion explosives having the composition shown in Table 1 were used except that polyoxyethylene (6) sorbitol oleate tetraester was used instead of sorbitan monooleate in Examples 1 to 3. is the first
Example 1 with the formulation composition of Examples 4 to 6 shown in the table.
Manufactured in accordance with. These W/O type emulsion explosives were packaged in the same manner as in Example 1 and tested on the same items. The results are shown in Table 1. Example 7 A W/O emulsion explosive having the composition shown in Table 1 was prepared by using an oxidizing agent aqueous solution of ammonium nitrate, sodium nitrate, calcium nitrate, and water instead of the oxidizing agent aqueous solution of ammonium nitrate, sodium nitrate, and water in Example 1. It was produced according to Example 1 using the formulation composition of Example 7 shown in Table 1, except that liquid paraffin was used instead of microcrystalline wax. These W/O type emulsion explosives were packaged in the same manner as in Example 1 and tested on the same items. The results are shown in Table 1. Examples 8-9 W/O type emulsion explosives having the composition shown in Table 1 used the same raw materials as in Example 1, but
It was produced according to Example 1 using the formulation compositions of Examples 8 and 9 shown in Table 1, except that the blending amount of "Micropearl F-30", which is a micro hollow sphere made of a thermally expandable resin, was increased. Example 1 These W/O type emulsion explosives
The product was packaged in the same manner as the product and tested on the same items. The results are shown in Table 1. Comparative Example 1 A W/O emulsion explosive having the composition shown in Table 2 was produced as follows. First, 78.36% of ammonium nitrate and 4.70% of sodium nitrate were added to 11.3% of water and dissolved by heating to obtain an oxidizing agent aqueous solution at about 100°C.
Meanwhile, sorbitan oleate monoester 1.79%
and 3.50% microcrystalline wax was heated and melted to obtain a combustible mixture at about 100°C. Next, first put the combustible agent mixture in a heat-insulating container, and stir it for 5 minutes at about 1000 rpm using a propeller blade stirrer while gradually adding the oxidizing agent aqueous solution to create a W/O emulsion at about 95°C. Obtained. Next, it is sold by The Dow Chemical Company as micro hollow spheres made of a thermally expandable resin that has completed foaming and expansion and has a particle size of about 30 microns. Mix 0.30% of "Saran micro-hollow spheres (Saran Microsphere)" into the above W/O type emulsion and heat the mixture to about 120°C for 10 minutes.
By adjusting the temperature to about 600 rpm and stirring at about 100 rpm.
A W/O type emulsion explosive having a temperature of 0.degree. C. was obtained. This W/
The O-type emulsion explosive was rapidly cooled to 40-50°C, packaged in the same manner as described in Example 1, and subjected to the same performance tests. The result is second
Shown in the table. Comparative Examples 2 to 8 Comparative Examples 2 to 8 shown in Table 2 except that the W/O type emulsion explosives having the composition shown in Table 2 were changed from the emulsifier or micro hollow spheres in Comparative Example 1.
It was manufactured according to Comparative Example 1 with the following composition. Example 1 These W/O type emulsion explosives
The product was packaged in the same manner as the product and tested on the same items. The results are shown in Table 1. Comparative Example 9 A W/O emulsion explosive having a composition as shown in Table 2 contains an oxidizing agent aqueous solution of ammonium nitrate, sodium nitrate, calcium nitrate, and water instead of the oxidizing agent aqueous solution of ammonium nitrate, sodium nitrate, and water in Comparative Example 1. It was produced in accordance with Comparative Example 1 using the formulation composition of Comparative Example 9 shown in Table 2, except that liquid paraffin was used instead of microcrystalline wax. These W/O type emulsion explosives were prepared in Example 1.
The product was packaged in the same manner as , and performance tests were conducted on the same items. The results are shown in Table 2. Comparative Example 10 A W/O emulsion explosive with the composition shown in Table 2 has the same composition as Comparative Example 1, and was heated at approximately 1600 rpm using a propeller blade stirrer while gradually adding an oxidizing agent aqueous solution. The stirring method is the same, but the step of forming a W/O emulsion takes 5 minutes and the step of mixing micro hollow spheres takes 3 minutes.
In terms of minutes, the total time until cooling was shortened to 8 minutes, which is the same as in Example 1. (The total time of Comparative Example 1 was 15 minutes.) Other than that, it was manufactured according to Comparative Example 1 using the compounding composition of Comparative Example 10 shown in Table 2. These W/O type emulsion explosives were prepared in Example 1.
The product was packaged in the same manner as , and performance tests were conducted on the same items. The results are shown in Table 2.

【table】

【table】

【table】

[Table] W/O type obtained by blending minute hollow spheres of unfoamed thermally expandable resin specified in the present invention, uniformly mixing during or immediately after forming a W/O type emulsion, and then foaming and expanding. In the case of emulsion explosives (Examples 1 to 9), use a No. 6 detonator to -
The storage period for complete explosion at 5°C was 12 to 39 months, and the maximum pressure for complete explosion was 137 to 272 kg/cm ² . On the other hand, microscopic hollow spheres made of a thermally expandable resin that has already been expanded and expanded, or inorganic microscopic hollow spheres such as glass microhollow spheres and silica microscopic hollow spheres are mixed after forming a W/O emulsion. W/O type emulsion explosive (Comparative example 1
~10), the storage period for complete detonation at -5℃ using a No. 6 detonator is 5 to 19 months, and the maximum detonation pressure is
It was 33Kg/cm ² to 70Kg/cm ² . As explained above based on each Example and each Comparative Example, micro hollow spheres made of an unfoamed thermally expandable resin defined by the present invention are blended and expanded during the production of a W/O emulsion explosive composition. The W/O type emulsion explosive obtained by this method has a smaller diameter (25 mm diameter) and lower temperature than the W/O type emulsion explosive obtained by a known manufacturing method. It is clear that the stability of the detonation sensitivity over time and the resistance to dead pressure have been greatly improved.

Claims (1)

[Scope of Claims] 1. (a) a step of preparing an oxidizing agent aqueous solution containing ammonium nitrate as a main component, (b) a step of preparing a combustible agent mixture consisting of an emulsifier and an oil, and (c) the above-mentioned oxidation. a step of emulsifying and mixing an aqueous solution of the agent and a combustible agent mixture to form a water-in-oil emulsion, (d) a step of mixing micro hollow spheres into the water-in-oil emulsion, and (v) a subsequent step of packaging. In a method for producing a water-in-oil emulsion explosive, unfoamed thermally expandable resin is uniformly mixed in the form of micro hollow spheres during or immediately after the formation process of a water-in-oil emulsion, and a desired temporary explosive is formed. A method for producing a water-in-oil emulsion explosive characterized by foaming it to a specific gravity. 2 Micro hollow spheres made of thermally expandable resin have a shell wall made of a ternary copolymer of vinylidene chloride, acrylonitrile, and methacrylic acid ester, and contain low-boiling hydrocarbons, and have an apparent specific gravity of 0.01 to 0.01 at 70°C to 140°C.
The method for producing a water-in-oil emulsion explosive according to claim 1, which is a micro hollow sphere characterized by foaming up to 0.50. 3 Micro hollow spheres made of thermally expandable resin have a shell wall made of a binary copolymer of acrylonitrile and methacrylic acid ester, and contain low boiling point hydrocarbons.
The method for producing a water-in-oil emulsion explosive according to claim 1, which is a micro hollow sphere that is foamed at 150°C to an apparent specific gravity of 0.01 to 0.50. 4. The proportion of micro hollow spheres made of thermally expandable resin is 0.01 to 7 in the total amount of water-in-oil emulsion explosive composition.
% by weight. A method for producing a water-in-oil emulsion explosive according to any one of claims 1 to 3.