WO2003053884A1

WO2003053884A1 - Explosive

Info

Publication number: WO2003053884A1
Application number: PCT/JP2002/013222
Authority: WO
Inventors: Toshihiro Ogata; Hiroyuki Taniguchi; Yoshimasa Sato
Original assignee: Nippon Kayaku Kabushiki Kaisha
Priority date: 2001-12-20
Filing date: 2002-12-18
Publication date: 2003-07-03
Also published as: CN1606537A; TWI289547B; AU2002366768A1; KR20040075008A; EP1457474A4; CA2470861A1; CN1291952C; KR100824932B1; TW200301236A; US20050155682A1; EP1457474A1

Abstract

A water-in-oil emulsion explosive characterized by containing an ethylene/vinyl acetate copolymer. It has excellent long-term stability. Even when stored under a load for as long as about one year, the explosive is less apt to suffer a decrease in explosive performance and coagulates only slightly in such a degree that it comes to have weakly coherent partial coagulates which can be easily disaggregated. Even after long-term storage, charging with the explosive can be easily conducted with a charger. Since the explosive has excellent water resistance, it is suitable also for blasting in a water hole.

Description

Explosives Technical field

The present invention relates to explosives. More specifically, it relates to a water-in-oil emulsion explosive used for industrial blasting operations such as tunnel excavation, quarrying, and mining. Background art

Well-known industrial explosives used in blasting operations include dynamite, hydrous explosives, nitrate explosives, and nitrate oil explosives (hereinafter referred to as ANFO explosives). Of these explosives, hydrous explosives are relatively safer than conventional dynamite because they do not contain explosive components in the composition, and have become widely used as industrial explosives. These explosives can be broadly classified into two types: slurry explosives and emulsion explosives. Emulsion explosives are characterized by better moldability and better weatherability. Since this emulsion explosive was published in U.S. Patent No. 3,161,551 as a water-in-oil emulsion explosive, various improvements have been made, and at present water resistance and safety In this regard, some explosives have better performance than conventional explosives.

At the blast site, on the other hand, there is an increasing demand for mechanized explosive charging work from the viewpoint of simplifying the explosive charging work and ensuring safety when handling explosives. In order to carry out mechanical loading of explosives, the explosives used must be safer, and methods of mechanically loading ANFII explosives with loaders and the like have been put to practical use in mines and quarries. However, compared to the water-in-oil emulsion explosive, the AN FO explosive requires a sufficient exhaust system because the residual gas composition after blasting is poor. Also, if water is present in the blast holes, the ANFO explosives will dissolve in the water and the desired explosive performance will not be obtained, making it difficult to use. For this reason, in a blast hole where water is present, discharge the water in the blast hole in advance, insert a polytube, etc., and then charge the ANFO explosive into the polytube. Complicated methods may be performed. In addition, for water-in-oil emulsion explosives, for example, in other countries, as described in the “Study Report on Effective Tunnel Technology” issued by the Japan Tunneling Technology Association, an oil called bulk emulsion explosive is used. A method called the Parque emulsion explosive system, which automatically loads a water-drop type emulsion explosive directly into a blast hole using an air-driven monopump or the like, has already been put into practical use. However, for bulk emulsion explosive systems, the use of high-viscosity water-in-oil emulsion explosives can lead to high costs due to complicated cleaning work after charging and management of residual explosives. . In addition, to load bulk emulsion explosives, expensive loading machinery is required to ensure safety.

Therefore, there is a demand for a highly safe explosive that can be loaded with a relatively simple machine such as an air loading machine and can be used even in a blast hole where a relatively large amount of water exists. As a method for solving these problems, for example, Japanese Patent Application Laid-Open Nos. 7-228388 and 11-2798975 describe a method for dissolving in granules or granular oils. Water-based emulsion explosives are being developed.

However, the granules or granulation method of the water-in-oil emulsion explosive described in the above-mentioned publication is based on crystallizing an aqueous solution of an inorganic oxidizing agent in an emulsion, breaking the emulsion structure, and then granulating. Things.

It is generally known that when an oxidizing aqueous solution of a water-in-oil emulsion explosive is crystallized, the emulsion breaks from the crystallized portion, making it impossible to maintain sensitivity and performance as an explosive. . Even for such explosives, if the on-site mixing method or a method similar to this is used, the time from explosive production to use is very short, a few hours or a few days, which is a very serious problem. Must not. However, explosives can usually last several months, from as long as six months to nearly a year, from the time they are manufactured until they are used. Therefore, it is required that granules or granular water-in-oil emulsion explosives do not crystallize the oxidizing agent aqueous solution and are stable over time for several months. In particular, it is desirable that the explosive is stable so that the properties of the water-in-oil type emulsion explosive do not change for a long period of time so that the explosive can be used for machine loading. In addition, when a granulated explosive is subjected to a load such as long-term storage or mechanical loading, the drug may agglomerate and may not be loosened during use, making it difficult to use. Therefore, it is desirable to use granular water-in-oil emulsion explosives that do not agglomerate even under heavy loads, such as long-term storage and mechanical loading, or that the agglomerates are easily loosened. Disclosure of the invention

The present inventors have conducted intensive studies in order to solve such problems, and as a result, have replaced or partially substituted the entire or a part of the continuous phase component of the water-in-oil emulsion with an ethylene vinyl acetate polymer. The inventors have found that a solid explosive having appropriate strength and stable for several months or more can be obtained when contained in a continuous phase component to form a water-in-oil type emulsion explosive, thereby completing the present invention.

That is, the present invention provides:

(1) a water-in-oil emulsion explosive characterized by containing an ethylene-vinyl acetate copolymer in a continuous phase,

(2) The emulsion explosive according to the above (1), wherein the content of the ethylene-vinyl acetate copolymer is 0.2 to 8% by mass relative to the total amount of the explosive.

(3) a water-in-oil emulsion explosive characterized by containing an oxidizing agent, oils, an ethylene-vinyl acetate polymer, an emulsifier, and fine hollow spheres;

(4) The emulsion explosive according to the above (3), wherein the minute hollow sphere is a glass microballoon or a resin microballoon.

(5) The emulsion explosion according to the above (3), wherein the proportion of the ethylene-vinyl acetate copolymer is 30% by mass or more based on the total mass of the oils and the ethylene-vinyl acetate copolymer.

(6) The emulsion explosive according to the above (3), wherein the melt flow rate of the ethylene-vinyl acetate copolymer is 10 g / 10 min. Or more.

(7) The emulsion explosive described in (3) above, wherein the number average molecular weight of the ethylene-pinyl acetate copolymer is 100 to 50,000.

(8) The solid according to any one of the above (1) to (7), which is solid. Emulsion explosives,

(9) The explosive according to the above (8), which is formed into a column having a diameter of 3 to 20 mm and a length of 1 to 30 mm,

About. BEST MODE FOR CARRYING OUT THE INVENTION-Hereinafter, the present invention will be described in detail. In the following, “parts” and “%” are based on mass unless otherwise specified.

In the water-in-oil emulsion explosive of the present invention, the continuous phase is an oil phase (fuel phase). Usually, a mixture containing both oils and an ethylene-vinyl acetate copolymer (hereinafter also referred to as EVA resin) is used. preferable. In the present invention, the oil phase, which is a continuous phase, may contain no oils in some cases, and may be formed of an EVA resin or a mixed resin composed of the resin and another resin;

The EVA resin is preferably a resin which has a property of being cured or its viscosity lowered by heat, and which can be injection-molded when mixed with an oxidizing agent, water, an emulsifier, fine hollow spheres and, if necessary, an oil. More specifically, those having a number average molecular weight within the range of about 100 to 60,000 are usually used, and those having a molecular weight of about 100 to 50,000 are preferable. More preferably, the molecular weight is 2,000 or more, more preferably 10,000 or more, and preferably in the range of 40,000 or less. '-The EVA resin used in the present invention may be a copolymer containing other copolymer components as long as it contains an ethylene-vinyl acetate copolymer as a main component. When the EVA resin is a copolymer containing another copolymer component, the proportion of the ethylene vinyl acetate copolymer portion to the whole EVA resin is preferably 30 to 100%; more preferably 50 to 100%. More preferably, it is 70% to 10.0%. Most preferred is an ethylene-vinyl acetate copolymer substantially free of other copolymer components. In the case of an ethylene vinyl acetate copolymer, the ratio of ethylene to pinyl acetate is not particularly limited, but usually, a molar ratio of vinyl acetate: ethylene = 1: 9 to 1:15 is preferable. The content of the ethylene-vinyl acetate copolymer with respect to the entire explosive of the present invention may be any amount as long as the effect of the present invention is exhibited, but is preferably 0.2% or more, more preferably 0.4% or more, and still more preferably. Is 0.6% or more, and 8% or less, more preferably 6% or less, and further preferably 4% or less. Although it depends on the type of the ethylene-vinyl acetate copolymer, the most preferable range is usually about 0.6 to 3%.

In the present invention, the continuous phase is preferably a mixture containing an oil described below and an ethylene-vinyl acetate copolymer. The resin contained in the continuous phase may be an EVA resin alone, but may contain a resin other than the ethylene-vinyl acetate copolymer as long as the effects of the present invention are exhibited. Other resins preferably exhibit oil solubility or compatibility with oils.

Examples of the other resin include a thermosetting resin, a thermoplastic resin, and a synthetic rubber. Specifically, vulcanized rubber, petroleum resin, phenolic resin, AAS resin, ABS resin, PET resin, urea resin, melamine resin, epoxy resin, unsaturated polyester resin, polyurethane resin, polyvinyl chloride, polyvinyl acetate, Examples thereof include a polyamide resin, a polyimide resin, and a polyethylene resin, but a resin that does not react with other components is preferable in order to maintain the stability of the water-in-oil emulsion. Further, a thermosetting resin having a liquid or low melting point at room temperature or a thermoplastic resin which is solid at room temperature and exhibits fluidity when heated is preferable. Specific examples include phenol resin, petroleum resin, polyethylene, polypropylene, polybutylene, polyisobutylene, ethylene-vinyl acetate copolymer resin, polybutadiene, styrene-butadiene rubber, etc., and petroleum resin or ethylene-vinyl acetate copolymer resin preferable. Further, petroleum resins among these may or may not be hydrogenated Teatsu, for example aliphatic or G petroleum resin G fraction of the cracked oil fraction and the raw material, the C ₉ fraction material use the aromatic or C ₉ petroleum resin, both have a like GC ₉ copolymer petroleum resins in the raw material within. Of these, resins made from the C5 fraction are, for example, copolymers such as isoprene, piperylene, and 2-methylbutene-1 and 2, and conjugated diolefins often have a cyclized structure. What is possessed is a typical example.

(In the formula, m and n represent the number of repetitions.)

The resin made from the G fraction is, for example, a copolymer containing styrene, vinyltoluene, a-methylstyrene, indene, or the like as a main component. It is. + ·.

(In the formula, n represents the number of repetitions.)

Hereinafter, in this specification, the term "oil mixture" means a mixture of EVA resin and oil or / and EVA resin unless otherwise specified.

In the present invention, the continuous phase is formed in an oil mixture. The ratio of the EVA resin to the total amount of the oils and the EVA resin is not particularly limited as long as the effects of the present invention are achieved, but is usually 10% or more, preferably 20% or more. All may be EVA resin. More preferred, however, is when the EVA resin is 30-80% of the total oil mixture. When other resins are used in combination, it is preferable to use them together so that the EVA resin is contained in the above-mentioned lower limit or more and the total amount of the EVA resin and the other resin is not more than the above-mentioned upper limit. The preferred content of the EVA resin will vary slightly depending on the molecular weight of the EVA resin, A relatively small amount may be used, and a relatively high amount tends to be better for a low molecular weight. For example, when the number average molecular weight is greater than 10,000, preferably 12,000 or more, more preferably 20,000 or more, the content may be 60% or less, preferably 25% or less, based on the total amount described above. About 50%. In the case of a low molecular weight EVA resin having a number average molecular weight of about 2,000 to 3,000, its content is at least 50%, more preferably about 60 to 80%.

In the production process of the water-in-oil emulsion explosive of the present invention, since the EVA resin is usually used in a molten state, it is preferable that the EVA resin melt at the production temperature. For example, an EVA resin having a melt flow rate of 10 gZl 0 min or more, preferably 15 g / 1 Omin or more, measured based on the “Flow Test Method for Thermoplastics” described in JISK 7210. It is desirable to use

Also, when a resin other than the EVA resin is used in combination, the same can be said for the other resin as well as the EVA resin.

The number average molecular weight of the resin can be measured, for example, by gel permeation chromatography or the like.

The explosive of the present invention usually contains oils. Oils that are commonly used in water-in-oil emulsion explosives can be used. Oils increase the emulsifiability of the emulsion and form a continuous phase with the EVA resin. Oils include petroleum oils such as light oil, kerosene, mineral oil, lubricating oil, heavy oil, petroleum waxes such as paraffin wax and microcrystalline wax, other hydrophobic vegetable oils, vegetable oils, animal oils, etc. Animal waxes can be used, and these can be used alone or in combination of two or more.

In the present invention, the oil mixture containing the oil is contained in the explosive in an amount of usually 0.1 to 20%, preferably 1 to 10%. In a preferred embodiment of the present invention, when a resin having a number average molecular weight of 100 to 50,000 is used, the amount of the oil mixture used is usually 0.1 in the explosive based on the total amount. % Or more, preferably 0.5% or more, more preferably 1% or more, and still more preferably 1.5% or more. The upper limit is usually about 10%, preferably 7% or less. A particularly preferred range is about 2 to 5%. Examples of the emulsifier used in the explosive of the present invention include emulsifiers commonly used in water-in-oil emulsion explosives, for example, those having 15 to 30 carbon atoms such as alkali metal stearate, ammonium stearate or calcium stearate. Degree of fatty acid salt

(Preferably, alkali metal salts, earth metal salts and ammonium salts, etc.), polyoxyethylene ethers, fatty acid esters, preferably fatty acid esters having 15 to 30 carbon atoms, such as sorbitan fatty acid esters And solzetol fatty acid esters. These are used as one kind or as a mixture of two or more kinds. The content of the emulsifier in the explosive is 0.1% or more, preferably 0.5% or more, more preferably 1% or more, and the upper limit is usually about 10%, preferably 7%. % Or less, more preferably 5% or less.

The oxidizing agent used in the explosive of the present invention is preferably used as an aqueous solution thereof. Examples of the oxidizing agent include nitrates and perchlorates.Specific examples include alkali metal nitrates such as sodium nitrate, alkaline earth metal nitrates such as calcium nitrate, ammonium nitrate, ammonium nitrate, and sodium chlorate. Alkaline earth metal chlorates such as alkali metal chlorate, calcium chlorate, alkali metal perchlorates such as potassium perchlorate, alkaline earth metal perchlorates such as calcium perchlorate, And ammonium perchlorate. These can be used alone or in combination. Particularly preferred among these oxidizing agents are ammonium nitrate and sodium nitrate. As described later, the oxidizing agent content in the oxidizing agent aqueous solution is preferably adjusted so that the crystallization temperature of the aqueous solution is 30 to 90 ° C. depending on the purpose of use and the like. Therefore, although it varies depending on the type of the oxidizing agent, it is usually 60 to 95%, preferably 70 to 93%, more preferably 85 to 92%.

The aqueous solution of the oxidizing agent used in the present invention may, if desired, contain a water-soluble amine nitrate such as monomethylamine nitrate, monoethylamine nitrate, hydrazine nitrate or dimethylamine dinitrate, or a water-soluble alcohol such as methanolamine nitrate or ethanolamine nitrate. It is possible to add, as auxiliary sensitizers, nitrolamine nitrates and water-soluble ethylene glycol mononitrate.

Preferably, the oxidizing agent aqueous solution used in the present invention is suitably adjusted so that the crystal precipitation temperature is 30 to 90 ° C. The water content in the oxidizing agent aqueous solution is It is used in a proportion of usually 5 to 40%, preferably 7 to 30%, particularly preferably 8 to 15%, based on the total amount of the solution. A water-soluble organic solvent such as methyl alcohol, ethyl alcohol, formamide, ethylene glycol, and dalyserin can be used as an auxiliary solvent to lower the crystallization temperature of the oxidizing agent aqueous solution. In the explosive of the present invention, the oxidizing agent aqueous solution (which may contain an auxiliary solvent) is the remainder of the explosive of the present invention except for the content of other components, and is preferably 60 to 97% based on the total amount. , More preferably in the range of 80-95%.

By adding an appropriate amount of a low-density bulking agent, preferably a fine hollow sphere, to the water-in-oil emulsion explosive of the present invention, the sensitivity performance of the explosive ranges from primer detonation to booster detonation. Can be adjusted. The density of the low density extender is usually 0.8 g / cc or less, preferably 0.5 g / cc or less, more preferably 0.3 gZc c or less, and in the case of an organic low density extender, 0.3 g / cc. / cc or less, and in some cases 0.05 g / cc or less can be used. As the low-density extender, any inert low-density one may be used, but a micro hollow sphere is preferable in order to obtain stable explosive performance. As the micro hollow sphere, for example, one or a mixture of two or more inorganic hollow spheres such as glass micro balloons and shirasu balloons, and organic hollow spheres such as expanded styrene and resin micro balloons are used. Resin microphone balloons are preferred, and glass microballoons are particularly preferred. The amount of the low-density extender varies widely depending on the application of the explosive and depends on the specific gravity of the micro hollow sphere, so it cannot be specified unconditionally, but usually the density of the explosive is 0.8 g / cc. As described above, the amount is preferably 0.9 g / cc or more, more preferably 1 gZcc or more, and is preferably used in an amount of 1.4 gZcc or less, preferably 1.3 g / cc or less. The preferred range of the compounding amount is about 0.1 to 10%, more preferably 1 to 8%, more preferably 1 to 6%, and in some cases, the optimal range is 2 to 5% based on the total amount of the explosive of the present invention. It is. In the case of the glass microballoon, which is a preferred embodiment of the present invention, the preferable blending amount is 1% or more, and in some cases, 2% or more, 8% or less, and more preferably 5% or less.

The water-in-oil emulsion explosive of the present invention may contain metal powders such as aluminum powder and magnesium powder, and organic powders such as wood powder and starch. These are added Depending on the type of substance and the purpose of addition, it is usually contained in explosives in the range of 0 to 10%.

The explosive of the present invention is manufactured, for example, as follows.

That is, the oxidizing agent and, if necessary, the auxiliary sensitizing agent are dissolved in water at about 85 to 95 ° C. to obtain an oxidizing agent aqueous solution. Further, the oil mixture component (eg, EVA resin and oils, if necessary, a resin other than EVA resin, etc.) and the emulsifier are sufficiently mixed with heat to obtain an oil mixture containing the emulsifier. Next, the above-mentioned oxidizing agent aqueous solution is gradually added to the oil mixture heated to about 85 to 95 ° C. with sufficient stirring to obtain a water-in-oil emulsion base material. Then, while maintaining this temperature, a low-density bulking agent, for example, fine hollow spheres, and other additives as necessary, are added to the water-in-oil emulsion, and the mixture is mixed with a kneading machine. Emulsion explosives can be obtained. The obtained explosive can be obtained as a molded explosive of the present invention by transferring it to a molding machine while molding it in a state of fluidity or cooling it to room temperature and molding it.

Here, when obtaining the water-in-oil type emulsion, a part of the oil mixture component may be added when adding the microscopic hollow spheres. For example, first, an oil and an emulsifier are mixed to form a water-in-oil emulsion, and EVA resin is added and mixed when adding minute hollow spheres to the emulsion. Emulsions may be used, and oils may be added and mixed when the micro hollow spheres are added.However, usually, as described above, the oil mixture component and the emulsifier are mixed to form an oil mixture containing the emulsifier. It is preferable to obtain a water-in-oil emulsion and add micro hollow spheres to it.

The water-in-oil emulsion explosive of the present invention thus obtained is preferably used after being formed into an appropriate shape by a conventional method. The shape of the formed explosive of the present invention is not particularly limited, and the explosive may be formed into an arbitrary shape by a molding machine which can be used in any of spherical, columnar, disk-like, and prismatic shapes. It may be formed into any shape, but the size is preferably such that the maximum length (the length of the longest side or the maximum length) in the shape is 30 mm or less, more preferably 20 mm or less. The shortest length (the length of the shortest side or the shortest length) is preferably 1 mm or more, more preferably 3 mm or more. Examples of the method for producing the explosive of the present invention include a method using an extruder generally used, and a method in which a water-in-oil emulsion explosive is pulverized by a pulverizer or the like and then granulated by a granulator or the like. Can be However, since the latter method complicates the process, extrusion molding is preferred. Specifically, for example, a water-in-oil emulsion explosive is extruded through a perforated plate or screen to form a water-in-oil emulsion explosive into a rod shape, and then cut into appropriate lengths with a knife, wire, etc. Of the molded product. In the molded explosive of the present invention, if the molded article is too large, the porosity increases when the explosive is charged into the blast hole, and the explosive charge as an explosive is reduced. The length is l ~ 30mm, preferably about 5 ~ 10mm in diameter and about 3 ~ 20mm in length.

The cylindrical explosive of the present invention can be manufactured by a method as simple as a conventional water-in-oil emulsion explosive. Example

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1

An aqueous solution of oxidizing agent consisting of 75.0 parts of ammonium nitrate, 4.8 parts of sodium nitrate and 6.6 parts of water at 90 ° C consisting of 1.5 parts of microcrystalline wax, 1.5 parts of microcrystalline wax, ethylene-vinyl acetate copolymer resin (Mitsui DuPont Polypropylene) Made by Chemical Co., Ltd., trade name: Evaflexs P-2807; number average molecular weight 20000-30000, melt flow rate 15 g / 10min, 1.4 parts, sorbitan monooleate 2. 9 parts mixture In addition, the mixture was sufficiently stirred and mixed to obtain a water-in-oil emulsion. To this, 3.8 parts of glass micro balloon (specific gravity 0.25 ((:)) as a minute hollow sphere was added and stirred and mixed to obtain a water-in-oil emulsion explosive of the present invention. The type emulsion explosive was molded by an extruder with a die of 8 mm in diameter and cut with a knife so as to have a length of 1 Omm to obtain the explosive of the present invention. Met. Example 2.

A 90 ° C oxidizing agent solution consisting of 75.0 parts of ammonium nitrate, 4.8 parts of sodium nitrate and 10.6 parts of water was added to 1.5 parts of microcrystalline wax, 1.5 parts of ethylene vinyl acetate copolymer resin (Tosoichisha Co., Ltd.) Product name: Ultracene 720; number average molecular weight approx. 37,000, melt flow rate: 150 g / 10 min.) 1. 4 parts, sorbitan monooleate 2. Add to 9 parts of the mixture, mix well and mix well Thus, a water-in-oil emulsion was obtained. Glass microballoons 3.8 as micro hollow spheres

(Specific gravity: 0.25 g / cc) and mixed by stirring to obtain a water-in-oil emulsion explosive of the present invention. This water-in-oil type emulsion explosive was molded by an extruder having a die of 8 mm in diameter and cut with a knife so as to have a length of 1 Omm to obtain the explosive of the present invention. The specific gravity of the obtained explosive was 1.17. Comparative Example 1

A 90 ° C aqueous solution of an oxidizing agent consisting of 75.0 parts of ammonium nitrate, 4.8 parts of sodium nitrate and 10.6 parts of water was added to a mixture of 3.8 parts of microcrystalline wax and 2.0 parts of sorbitan monooleate. After sufficiently stirring and mixing, a water-in-oil emulsion was obtained. To this, 3.8 parts (specific gravity: 0.25 g / cc) of the same glass microballoons as in the example as micro hollow spheres were added and mixed by stirring to obtain a water-in-oil type emulsion explosive for comparison. This water-in-oil type emulsion explosive was molded by an extruder with a die of 8 mm in diameter, and cut with a knife to a length of 1 Omm to obtain a comparative explosive. The specific gravity of the obtained explosive was 1.17. Table 1 shows the composition ratios of the water-in-oil emulsion explosives obtained in Examples 1 to 3 and Comparative Example 1. Composition ratio

Example 1 Example 2 Comparative Example 1

Ammonium nitrate 75.0 75.0 75.0

Sodium nitrate 4.8 4.8 4.8

Water 10.6 10.6 10.6

Microstalin wax 1.5 1.5 3.8

Sorpitan monopole 2.9 2.9 2.0

Evaflex P-2807 1.4

Ultracene 720 1.4

Glass microphone mouth balloon 3.8 3.8 3.8 Test example

The explosives obtained in Examples 1 to 2 and Comparative Example 1 were charged into a steel pipe having an inner diameter of 48 mm, a length of lm, and a thickness of 5 mm using an air-loading machine. It was detonated using 50 g of a water-containing explosive (trade name: Artex) manufactured by K.K., and the detonation velocity was measured by the Doritish method. After the same steel pipe was filled with water in advance, each explosive was loaded using an air-spotting machine in the same manner as above, and the detonation velocity in the water hole was measured. In addition, as a aging test, the molded explosive obtained above was stored in a vinyl bag so as to have a thickness of about 15 to 20 cm, and stored at room temperature for 6 months and 1 year. The detonation rate was measured in the drying hole and the water hole in the same manner as above. The results are shown in Table 2.

In addition, in order to investigate the solidification properties of the granular emulsion explosives under load and the ease of solidification, etc., 20 kg of the explosives obtained in Examples 1-2 and Comparative Example 1 were actually wrapped (put in a bag and put on a cardboard box). Storage at room temperature for 6 months and 1 year. The state of explosives after storage for 6 months and 1 year was observed and evaluated. Table 2 shows the test results. Table 2 '' Performance test results

Regarding the performance test results: As shown in Table 2, the explosive of the present invention did not harden after storage for one year and had the initial performance when stored at room temperature under no load. In contrast, the explosive of the comparative example could measure the detonation speed immediately after production, but even after storage for 6 months at room temperature under non-weighted conditions, it became a lump, as shown in Table 2. Detonation velocity measurement was not possible.

As for the solidification property under load, in the case of the present invention, light partial solidification was observed after 6 months and 1 year, but it was easily disintegrated by applying a slight impact. There was no problem in loading the explosives with the loading machine. However, in the case of the comparative example, after 6 months and 1 year, it became a dumpling-like mass, it was difficult to eliminate the solidified state, and it was difficult to load with the loading machine. Example 3

From 75.0 parts of ammonium nitrate, 4.8 parts of sodium nitrate and 10.6 parts of water A 90 ° C aqueous solution of an oxidizing agent is added to 2.0 parts of microcrystalline wax, ethylene vinyl acetate copolymer resin (manufactured by Tosoh Corporation, trade name: Ultracene 722; Meltoff mouth—rate 400 gZl 0 min.) 0 9 parts, sorbitan monooleate 2.9 parts were added to the mixture and mixed well with stirring to obtain a water-in-oil emulsion. To this, 3.8 parts of glass microballoons (specific gravity 0.25 g / cc) as minute hollow spheres were added and mixed by stirring to obtain an oil-in-water-drop emulsion explosive of the present invention. This water-in-oil emulsion explosive was molded by an extruder with a die having a diameter of 8 mm and cut with a knife so as to have a length of 1 Omm to obtain the explosive of the present invention. The specific gravity of the obtained explosive was 1.17.

The obtained explosives were tested for detonation speed, solidification, and ease of solidification in the same manner as in the test examples. Table 3 shows the results. Table 3

Industrial applicability

The water-in-oil emulsion explosive of the present invention is hardly deformed or agglomerated by a load, and can be easily disintegrated to the extent that it causes light partial solidification even under long-term storage of half a year to one year under a load. It has long-term stability over time and has excellent water resistance. Therefore, when the explosive of the present invention is appropriately molded, it can be used for air charging or the like. It can be easily loaded into blast holes using a loading machine, and can be used in water holes without deteriorating explosive performance. The residual gas composition after blasting is also better than that of ANF II explosives.

Claims

Scope of claim

1. A water-in-oil emulsion explosive characterized by containing an ethylene-pinyl acetate copolymer in a continuous phase.

2. The emulsion explosive according to claim 1, wherein the content of the ethylene-pinyl acetate copolymer is 0.2 to 8% by mass relative to the total amount of the explosive.

3. A water-in-oil emulsion explosive characterized by containing an oxidizing agent, oils, an ethylene-pinyl acetate polymer, an emulsifier, and fine hollow spheres. ·

4. The emulsion explosive according to claim 3, wherein the micro hollow sphere is a glass micro balloon or a resin micro balloon.

5. The emulsion according to claim 3, wherein the proportion of the ethylene vinyl acetate copolymer is 30% by mass or more based on the total mass of the oils and the ethylene vinyl acetate copolymer.

6. The emulsion explosive according to claim 3, wherein the ethylene vinyl acetate polymer has a melt flow rate of lOgZlOmin. Or more.

7. The emulsion explosive according to claim 3, wherein the number average molecular weight of the ethylene vinyl acetate polymer is 100 to 50,000. .

8. The emulsion explosive according to any one of claims 1 to 7, which is a solid.

9. The explosive according to claim 8, wherein the explosive is formed into a column having a diameter of 3 to 20 mm and a length of 1 to 30 mm. '