JPH0768074B2 - Water-in-oil emulsion explosive composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a water-in-oil (hereinafter referred to as W / O) emulsion explosive composition, which has a small diameter by containing a specific carbonaceous fuel. (25 mm diameter) and to a W / O emulsion explosive composition having improved handling such as making the drug substance hard without impairing the stability of initiation sensitivity at low temperature and facilitating loading at the time of blasting.

(Prior Art) Since W / O emulsion explosives were first published by US Pat. No. 3,161,551, various W / O emulsion explosives have been proposed according to their purposes.

The W / O emulsion explosives that have been proposed in the past basically include a continuous phase composed of a carbonaceous fuel, a dispersed phase composed of an aqueous solution of an inorganic oxidic acid salt, an emulsifier and a bubble retaining agent. .

W / O emulsion explosives with a small caliber and improved stability at time of initiation of detonation at low temperature, using a specific emulsifier, for example, a mixture of sorbide fatty acid ester, sorbitan fatty acid ester and sorbitol fatty acid ester in a specific ratio. Is known.
59-207889). The carbonaceous fuel specifically used here is a hydrocarbon oil obtained by refining a petroleum wax such as microcrystalline wax or a lubricating oil fraction such as liquid paraffin.

Also, as a W / O type emulsion explosive with improved stability over time, a specific emulsifier, for example, an emulsifier having a hydrophobic group composed of a long-chain unsaturated fatty acid such as sorbitan monooleate, and 30% or more of a urea non-addition component It is also known to use in combination with petroleum wax such as microcrystalline wax containing paraffin and paraffin wax (Japanese Patent Publication No. 60).
−8998 publication).

Also, as a W / O emulsion explosive with improved stability over time of blasting sensitivity, carbonaceous fuel is selected from epoxy resin, unsaturated polyester resin, polybutene, isobutylene, petroleum resin, and butadiene resin without containing oil. Those using a polymer have also been proposed (JP-A-61-40892).

The petroleum resin used here is a resin obtained by polymerizing the fraction obtained in the naphthalene decomposition process, and is a C ₅ petroleum resin or a C ₉ petroleum resin, preferably having a molecular weight of 1000 to 1400.

Further, for the same purpose as described above, it has been proposed to use a polymer selected from α-olefin polymers and copolymers thereof, pentadiene polymers and copolymers thereof, and alicyclic hydrocarbon resins as carbonaceous fuels. (Japanese Patent Laid-Open No. 61-4089
No. 3 bulletin).

The α-olefin polymer used here has 6 carbon atoms.
To 14 in the general formula CH ₂ ═CH—R (R is an alkyl group)
It is said that a polymer obtained by mainly polymerizing an α-olefin represented by the formula (1) and having a molecular weight of 300 to 100,000 is preferable, and a polymer having a molecular weight of 300 to 3,000 and liquid at room temperature is more preferable. Also in the specific examples, only an α-olefin polymer having a molecular weight of about 700 (manufactured by Lion Oil and Fats, trade name “Repolyp 70” pour point −55 ° C.) is shown, and this is an α-olefin oligomer that is liquid at room temperature.

In addition, as a W / O emulsion explosive with improved stability over time, one of oil components such as gear oil and polyethylene wax having an average molecular weight of 500 to 5,000, polypropylene having an average molecular weight of 5,000 or less, or atactic polypropylene having an average molecular weight of 15,000 or less is used. There has also been proposed one that is used as a carbonaceous fuel in combination with a polymer (Japanese Patent Laid-Open No. 57-1498).
No. 93 bulletin).

The polyethylene wax disclosed in the specific examples of this publication has an average molecular weight of 300,500,2000,5000,8000,
The melting point, the density and the terminal group are not described at all, and the trade names used are not described at all.

On the other hand, for the purpose of hardening the drug quality without impairing the stability over time, a specific emulsifier, that is, a specific amount of fatty acid and fatty acid soap, and sorbide fatty acid ester, sorbitan fatty acid ester and sorbitol fatty acid ester specific ratio There is also known one using a mixture consisting of (JP-A-62-162685). The carbonaceous fuel specifically used here is petroleum wax such as microcrystalline wax and paraffin wax and liquid paraffin.

(Problems to be solved by the invention) In the conventional W / O type emulsion explosive, a combination of a specific emulsifier or a specific emulsifier and a specific petroleum wax is used, but stability with time is improved. There was a problem that the drug quality did not become sufficiently hard.

Further, some carbonaceous fuels using a specific polymer have a high viscosity and a large adhesiveness, and there is a problem in terms of manufacturability of a W / O emulsion explosive. In addition, the manufactured explosive has a problem that the drug quality is not sufficiently hard even if it is improved in storage stability.

Also, as the carbonaceous fuel, the one using an α-olefin oligomer which is liquid at room temperature can improve the stability of the detonation sensitivity with time, but like the above, the problem of adhesiveness and the chemical quality do not become sufficiently hard. There was a problem.

Also, as a carbonaceous fuel, even with polyethylene wax used in combination with oil, if the number average molecular weight is less than 350, there is no effect of improving the drug quality, and if it exceeds 1,000, the stability of detonation sensitivity with time decreases. There was a problem. Further, even in the case of polyethylene wax having an average molecular weight of 350 to 1000, depending on the polar group at the terminal, for example, when the terminal is a carboxyl group, the emulsification is difficult and there is a problem in terms of manufacturability.

Furthermore, the one containing a specific amount of fatty acid or fatty acid soap and using an emulsifier consisting of a mixture in a specific ratio has a problem that it is difficult to always obtain a stable performance because the emulsifier is not a single component, Moreover, there was a problem that there was a limit in terms of drug quality and it was still insufficient.

As a carbonaceous fuel, by mixing a large amount of high melting point or high softening point oils or emulsifiers or adjusting the ratio of them, it is possible to manufacture those with a medicinal hardness to a certain degree, but oils with high viscosity or There has been a problem that increasing the amount of emulsifier deteriorates the stability of detonation sensitivity over time.

If the W / O emulsion explosive has a soft quality, it may be difficult to load because it may be deformed during transportation or deformed when it is loaded into the perforation, especially for products with a small diameter. It also became a cause of accidental residue.

On the other hand, the W / O type emulsion explosive must have good stability over time because the time after production is long for about 6 months to 1 year after use.

However, a W / O type emulsion explosive that fully satisfies both characteristics has not been proposed yet, and it is becoming a big problem to be solved.

Therefore, the present inventors have focused on carbonaceous fuels in consideration of manufacturability, product stability, and the like, and as a result of long-term research on various waxes and polymers, as a result, a specific low molecular weight polyethylene was used as a carbonaceous fuel. The present invention has been completed based on the finding that the use can solve the above technical problems.

(Means for Solving the Problem) The present invention is a W / O emulsion explosive containing a continuous phase composed of a carbonaceous fuel, a dispersed phase composed of an aqueous solution of an inorganic oxidic acid salt, an emulsifier and a bubble-retaining agent. The carbonaceous fuel has a melting point or softening point of 40 to 120 ° C, a number average molecular weight of 350 to 1000, a carbon number of 20 to 80, and a density of 0.9.
0 to 0.96 g / cc, low molecular weight polyethylene with no polar group at the end, and explosive penetration hardness of 10 to 20 mm
Or 5% by weight or more of this low-molecular-weight polyethylene, having a melting point of 40 ° C. or higher and containing 10% by weight or more of isoparaffin, selected from the group consisting of mineral waxes, animal and plant waxes, petroleum waxes, and synthetic waxes 1 It is a water-in-oil emulsion explosive composition characterized by containing 95% by weight or less of one kind or two or more kinds of wax and having a penetration hardness of 10 to 20 mm.

The carbonaceous fuel used in the present invention is a specific low molecular weight polyethylene as described above or a combination of this low molecular weight polyethylene and a specific natural wax and / or synthetic wax.

This low-molecular-weight polyethylene is completely different from an oligomer polymerized mainly with an α-olefin represented by the general formula ([CH ₂ ═CH—R] R is an alkyl group) which is conventionally known, and is solid at room temperature. Is.

In the present invention, the melting point or softening point of the low molecular weight polyethylene exceeds 120 ° C. or the number average molecular weight is 1000.
If it exceeds 80 (carbon number) or the density exceeds 0.96 g / cc, the viscosity becomes high and a hard drug substance is obtained, but on the other hand, the stability of detonation sensitivity with time deteriorates and the manufacturability also deteriorates.

Further, if the melting point or softening point is less than 40 ° C, the number average molecular weight is less than 350 (carbon number 20), or the density is less than 0.90, the viscosity is low, but the manufacturability is good, but the chemical quality becomes soft and continuous. The physical strength as a phase becomes weak, and the stability of detonation sensitivity with time also deteriorates. Particularly, the stability over time of the detonation sensitivity at low temperatures with a small diameter (25 mm) deteriorates. here,
The melting point or softening point is preferably 60 to 100 ° C in consideration of the manufacturability and the hardness of the drug substance.

Further, even if the low molecular weight polyethylene satisfies the above conditions,
If it has a polar group at its end, for example, if it has a carboxyl group or the like, it is difficult to emulsify, and W / which has excellent stability over time.
Cannot obtain O type emulsion explosive.

The measuring method of the melting point, softening point, number average molecular weight and density of low molecular weight polyethylene is a commonly used measuring method.

Low molecular weight polyethylene used in the present invention No. 1
Although specific examples are shown in the table, it goes without saying that the present invention is not limited to these commercial products.

None of these low molecular weight polyethylenes have a polar group at the end.

Further, in the present invention, a specific wax may be used in combination with the low molecular weight polyethylene, but the melting point of each of the mineral wax, animal and plant wax, petroleum wax, and synthetic wax is 40.
If it is less than ℃, the productivity is good because the viscosity is low, but
The drug quality becomes soft, the physical strength as a continuous phase becomes weak, and the stability with time deteriorates.

Further, if the content of isoparaffin is less than 10% by weight, since there are many chain components represented by normal paraffin, the crystallinity is high and the drug substance becomes hard, but the connection with the emulsifier is weak, and the continuous phase The physical strength becomes weak and the stability with time deteriorates.

Specific examples of the mineral wax, animal and plant wax, petroleum wax, and synthetic wax used in the present invention are shown in Table 2, but it goes without saying that they are not limited to these commercially available products.

The low molecular weight polyethylene used in the present invention is one or two.
It is used as a mixture of two or more kinds, and each of mineral wax, animal and plant wax, petroleum wax, and synthetic wax is also used as one kind or a mixture of two or more kinds.

The blending ratio of each of the mineral wax, animal and plant wax, petroleum wax, and synthetic wax to the low molecular weight polyethylene is usually 95% (weight basis, the same applies hereinafter) or less, preferably 80% or less.

If the mixing ratio of mineral, animal and plant waxes, petroleum waxes, and synthetic waxes to low molecular weight polyethylene exceeds 95%, the medicinal properties will become soft.

A carbonaceous fuel composed of low molecular weight polyethylene used in the present invention or carbon containing 95% or less of one or more waxes selected from the group consisting of mineral wax, petroleum wax and synthetic wax in this low molecular weight polyethylene. Quality fuel w /
The mixing ratio to the O-type emulsion explosive composition is usually 1 to 1.
It is 0%, preferably 2 to 5%.

When the blending amount of the carbonaceous fuel of the present invention is less than 1%, the W / O emulsion explosive tends to have poor stability over time in the small-diameter and low-temperature detonation sensitivity, which tends to deteriorate the drug quality. On the other hand, if it exceeds 10%, the oxygen balance tends to be poor, and the explosiveness and post gas tend to be poor.

The aqueous solution of the inorganic oxidic acid salt used in the present invention contains conventionally known ammonium nitrate as a main component, and optionally contains other inorganic oxidic acid salt. Other inorganic oxides are alkali metal or alkaline earth metal nitrates. In addition, water-soluble amine nitrates such as alkali metal or alkaline earth metal perchlorates, chlorates, etc., monomethylamine nitrates, monoethylamine nitrates, hydrazine nitrates, dimethylamine dinitrates, ethylenediamine dinitrates and methanolamine nitrates. ,
A water-soluble alkanolamine nitrate such as ethanolamine nitrate or a water-soluble ethylene glycol mononitrate can be used as an auxiliary sharpening agent.

A particularly preferred auxiliary sharpening agent is hydrazine nitrate, which has a large effect of promoting the dissolution of the inorganic oxide salt.

By using the auxiliary sharpening agent, the detonation reliability and the low temperature detonability can be improved.

The compounding amount of ammonium nitrate is generally 36 to 95%, and if necessary, other inorganic oxidic acid salt or the like can be contained in 40% or less of the total inorganic oxidic acid salt containing ammonium nitrate. When an auxiliary sharpening agent is used, its content is generally 40% or less, preferably 30% or less, and particularly preferably 20% or less based on the whole amount. If it exceeds 40%, the handling risk may increase.

The water used for the aqueous solution of the inorganic oxide is usually 5 to 25
%.

The emulsifier used in the present invention is a conventionally known W /
O are all emulsifiers that form emulsions. For example, sorbitan fatty acid ester, glycerin fatty acid ester, polyoxyalkylene sorbitol fatty acid ester, oxazoline derivative, imidazoline derivative, phosphoric acid ester, alkali metal salt or alkaline earth metal salt of fatty acid, primary, secondary and tertiary amines or them Nitrate or acetate. These emulsifiers are used alone or as a mixture of two or more.

The emulsifier content is generally 0.1 to 7%. It is preferably 0.5 to 4%.

Further, the W / O emulsion explosive composition of the present invention has a temporary specific gravity of 0.80 to 1.35 (preferably 1.00 to 1.
20) is adjusted.

The bubble-retaining agent is a conventionally known fine hollow sphere, a fine bubble or a bubble aggregate in which a large number of bubbles are aggregated to form primary particles (see JP-A-60-90887).

Examples of the hollow microspheres include glass, shirasu, silica sand,
Inorganic micro hollow spheres obtained from sodium silicate, etc., carbonaceous micro hollow spheres obtained from coal, etc., synthetic resin micro hollow spheres obtained from phenolic resin, polyvinylidene chloride, etc., or those treated from the surface Is. The content of the micro hollow spheres is generally 0.01 to 10%. Examples of the fine bubbles include fine bubbles obtained by foaming by containing a chemical foaming agent, or fine bubbles obtained by mechanically blowing air or other gas during or after the formation of the W / O emulsion. Air bubbles. The chemical foaming agent is, for example, an inorganic chemical foaming agent such as alkali metal borohydride or a combination of sodium nitrite and urea, or N, N′-dinitrosopentamethylenetetramine, azobisisobutyronitrile. Such as organic chemical foaming agents. The compounding amount of the chemical foaming agent is generally 0.
It is from 01 to 2%.

As the cell aggregate, polystyrene, ABS, polyethylene, polypropylene, polyvinyl chloride, cellulose acetate, a thermoplastic resin such as an acrylic resin, a natural rubber, a rubber such as a synthetic rubber and the like, or, or copolymerization of these various resins or A cell aggregate having a cell aggregate structure or a sponge-like cell aggregate structure obtained by adding various foaming agents such as an inorganic foaming agent, an organic foaming agent, and a foaming agent such as a low boiling point hydrocarbon to the modified resin. The compounding amount of the bubble aggregate is generally 0.05 to 15
%. These micro hollow spheres, chemical foaming agents and cell aggregates are used alone or as a mixture of one or more kinds.

In the present invention, when the cell aggregate is used as the cell retainer, there is no possibility that a part of the microscopic hollow sphere will be destroyed by pumping or the like at the time of production, so that the explosion as designed. It is possible to obtain performance and obtain an explosive which is also excellent in terms of stability over time.

Further, by using a combination of the micro hollow spheres and the cell aggregates as the cell retaining agent, the problem of breaking the micro hollow spheres can be solved.

In addition to the components described above, emulsion stabilizers that have been conventionally known,
For example, water or oil-insoluble powder having a size of 1 μm or less can be added. (See Japanese Patent Publication No. 58-15467). Further, a water-soluble phosphate as a stabilizer (see JP-A-59-78995) and a chelating agent may be added depending on the above components.

In particular, when hydrazine nitrate or the like is used as an auxiliary sharpening agent, it is advantageous to use a chelating agent such as sodium ethylenediaminetetraacetate because decomposition of hydrazine nitrate can be prevented.

Further, when it is used for coal mining, a conventionally known halide such as sodium chloride can also be added.

A brief example of the production of the above W / O emulsion explosive is described. Aqueous solution of inorganic oxidate is melted at 90 ℃, specific carbonaceous fuel and emulsifier are melted and mixed at 90 ℃, and the oxidate aqueous solution and the carbonaceous fuel are stirred and emulsified under heating at 90 ℃ The agent is added to obtain a W / O type emulsion explosive.

The hardness of the W / O emulsion explosive of the present invention thus obtained has a penetration hardness of 10 to 20 mm. Penetration hardness here means a 133g conical (30 °) iron cone 45mm
It is the depth of penetration when dropped from the height of.

(Effect of the invention) Since the W / O type emulsion explosive composition of the present invention contains a specific carbonaceous fuel, it has a small diameter (25 mm) as compared with a conventional W / O type emulsion explosive composition which does not contain it. (Diameter) It has an effect that the drug substance can be hardened without impairing the stability with time at low temperature, and the handleability such as easy loading at the time of blasting can be improved. Further, when the specific carbonaceous fuel of the present invention is used, the viscosity and the tackiness at the time of production are excellent and the productivity is excellent, and W / a specific emulsifier is mixed in a specific ratio for improving the drug quality.
Compared with the O-type emulsion field drug, the present invention has an effect that a product of constant quality can be obtained because a single emulsifier is used.

(Example) Next, the present invention will be specifically described with reference to Examples and Comparative Examples.

The present invention is not limited to the examples below. All parts in each example are by weight.

Example 1 A W / O emulsion explosive having the composition shown in Table 3 was produced as follows.

Ammonium nitrate 75.5 parts, sodium nitrate 5.0 parts water 12.
In addition to 2 parts, it melt | dissolved completely at 90 degreeC and the inorganic oxidizing agent aqueous solution was obtained. On the other hand, low molecular weight polyethylene (manufactured by Mitsubishi Kasei Co., Ltd., Dialene 30) as the carbonaceous fuel specified in the present invention 3.
A mixture of 0 parts and 1.7 parts of sorbitan monooleate as an emulsifier was melt-mixed at 90 ° C. to obtain a mixture of combustible agents. 92.7 parts of the above-mentioned oxidizing agent aqueous solution was slowly added thereto, and the mixture was stirred and emulsified at 90 ° C. while heating at 650 rpm. 18 minutes for 3 more minutes after emulsification
The mixture was stirred at 00 rpm to obtain 97.4 parts of W / O emulsion. 2.6 parts of glass micro hollow spheres (manufactured by The PQ Co., Ltd., glass micro hollow spheres Q-cel # 500) as a cell-holding agent, and the above W
After mixing and kneading 97.4 parts of / O type emulsion at 60-80 ° C,
Weighed 0 g each, molded into a cylinder with a diameter of 25 mm, and wrapped in viscose paper to obtain a W / O emulsion explosive.

As a performance test, (a) measurement of temporary specific gravity one day after production,
(B) Keep the test drug package at -40 ℃ for 2 hours, then at + 30 ℃
After carrying out a forced deterioration storage test in which the temperature cycle was maintained for 22 hours and repeating this cycle as one cycle, a detonation test was conducted at -15 ° C using a No. 6 detonator to determine the number of temperature cycles that could be completed. Sensitivity time stability test, (c) Sample medicine package
Hold at 50 ° C for 72 hours, then store at room temperature (0-30 ° C) for storage (1 year) and then detonate at low temperature. Low temperature detonation sensitivity test, (d) Penetration hardness (mm) measurement. I.e. 133g
The depth of penetration (mm) was measured when the iron cone (30 °) was dropped from a height of 45 mm.

The results of the various tests described above are shown in Table 3.

Examples 2 to 10 Based on Example 1, each compounding composition shown in Table 3 was used.
A W / O type emulsion explosive was obtained. The same test as in Example 1 was conducted for each W / O emulsion explosive. The test results are shown in Table 3.

Comparative Examples 1-8 Based on Example 1, each W / O type emulsion explosive was obtained with the compounding composition shown in Comparative Examples 1-8 of Table 3. The same performance test as in Example 1 was conducted for each W / O type emulsion explosive. The test results are shown in Table 3.

In Table 3, the carbonaceous fuels are shown below.

Wax Rex 602: Microcrystalline wax, melting point 81 ° C (manufactured by Mobil Sekiyu KK).

Hi-Mic 2045: Microcrystalline wax, melting point
60 ℃ (made by Nippon Seiro Co., Ltd.).

Dialene 208: Low molecular weight polyethylene, melting point or softening point 38 ° C, number average molecular weight 318 (carbon number 23), density 0.9
6g / cc (manufactured by Mitsubishi Kasei).

High Wax 200: Low molecular weight polyethylene, melting point or softening point 113 ° C, number average molecular weight 2000 (carbon number 143), density 0.97g / cc (Mitsui Petrochemical Co., Ltd.).

Polywax 2000: Low molecular weight polyethylene, melting point or softening point 125 ° C, number average molecular weight 2000 (carbon number 143),
Density 0.96g / cc (made by Petrolite).

Polybis 10N: polybutene, number average molecular weight 1000 (manufactured by NOF CORPORATION).

Evaflex 210: Vinyl acetate copolymer, 40% vinyl acetate content, softening point 85 ° C (Mitsui Polychemical Co., Ltd.).

Lipolube 70: α-olefin oligomer, number average molecular weight 700 (manufactured by Lion Yushi Co., Ltd.).

In Table 3, the air bubble-holding agents are as follows.

GMB (Q-cel # 500): Glass micro hollow sphere (The
Made by PQ).

SMB (SPW-7): Shirasu micro hollow body (Kushiro Coal Carbon Distillation Co., Ltd.).

RMB (Expancel DE): Polyvinylidene chloride resin balls (made by Chemanode Plastics).

Styrofoam pre-expanded beads: Styrofoam beads manufactured by Mitsubishi Yuka Birdish Co., Ltd., which were pre-expanded with beads of 0.2 mm or less (bulk specific gravity 0.3, average particle size 0.6 mm) From the relationship between the above Examples and Comparative Examples, The W / O type emulsion explosive composition using a specific number molecular weight polyethylene as the carbonaceous fuel (Examples 1 to 10) does not use W / O.
Compared with the type emulsion explosive compositions (Comparative Examples 1 to 8), the qualitatively harder without deteriorating the stability over time, the handleability is good even in the small-diameter products, and the blasting effect is preferable. It was confirmed that

Examples 11 to 18 Based on Example 1, each compounding composition shown in Table 4 was used.
A W / O type emulsion explosive was obtained. The same test as in Example 1 was conducted for each W / O emulsion explosive. The test results are shown in Table 4.

Comparative Examples 9 to 15 Based on Example 1, each of the compounding compositions shown in Table 4 was used.
A W / O type emulsion explosive was obtained. The same test as in Example 1 was conducted for each W / O emulsion explosive. The test results are shown in Table 4.

In Table 4, the carbonaceous fuels are shown below.

The same numbers as in Table 3 indicate the same items.

115 ° F paraffin: paraffin wax, melting point 46
℃, isoparaffin content 0% (manufactured by Nippon Seiro Co., Ltd.) OX-WISSEN-8: low molecular weight polyethylene, softening point 84
° C, number average molecular weight 950 (carbon number 67), density 0.94 g / cc, having a carboxyl group at the end (manufactured by Nippon Seiro Co., Ltd.). In Table 4, the air bubble-retaining agent is the same as in Table 3.

From the relationship between the above examples and comparative examples, specific low molecular weight polyethylene as a carbonaceous fuel, specific mineral-based, animal and plant-based, petroleum-based, synthetic wax 95% or less W /
The O-type emulsion explosive composition (Examples 1 to 18) is a W / O-type emulsion explosive composition not using it (Comparative Examples 9 to 1).
It was confirmed that, compared with 4), it became qualitatively hard without sacrificing stability over time, was easy to handle even for products with a small diameter, and had a favorable blasting effect.

Moreover, it was confirmed that even low molecular weight polyethylene as a carbonaceous fuel cannot be emulsified with a terminal having a polar group such as a carboxyl group (Comparative Example 15).

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Akihiro Tanaka 65-2 Gono, Uenoma, Mihama-cho, Chita-gun, Aichi (56) References JP-A-59-162194 (JP, A) JP-A-57-149893 (JP, A)

Claims (2)

[Claims] 1. A water-in-oil emulsion explosive which comprises a continuous phase composed of a carbonaceous fuel, a dispersed phase composed of an aqueous solution of an inorganic oxidic acid salt, an emulsifier and a bubble-retaining agent, wherein It has a melting point or softening point of 120 ° C, a number average molecular weight of 350 to 1000, a carbon number of 20 to 80, and a density of
0.90 to 0.96 g / cc, low molecular weight polyethylene with no polar group at the end, and explosive penetration hardness of 10 to 20
mm in water-in-oil emulsion explosive composition. 2. A water-in-oil emulsion explosive containing a continuous phase composed of a carbonaceous fuel, a dispersed phase composed of an aqueous solution of an inorganic oxidic acid salt, an emulsifier and a bubble-retaining agent, wherein the carbonaceous fuel is 40 to 120. It has a melting point or softening point of ° C, a number average molecular weight of 350 to 1000, a carbon number of 20 to 80, and a density of 0.9.
0 to 0.96 g / cc, 5% by weight or more of low molecular weight polyethylene having no polar group at the end, a melting point of 40 ° C. or more and 10% by weight or more of isoparaffin, mineral-based, animal-plant-based, petroleum-based, One or two or more waxes selected from the group consisting of synthetic waxes are mixed in an amount of 95 wt% or less, and the penetration hardness of the explosive is 10 to 20 mm. Water-in-oil emulsion explosive composition.