KR100449162B1 - Emulsion explosive with improved properties for impact resistance and storage stability - Google Patents

Abstract

The present invention relates to emulsion explosives used in the open-air and tunnel blasting site, to enhance the impact resistance by external impact and to improve the stability by long-term storage, the foam support agent used in the emulsion explosives is flexible and elastic Provides an emulsion explosive applied to plastic microspheres that are not broken, have excellent chemical resistance, and have a thicker shell.

Description

EMULSION EXPLOSIVE WITH IMPROVED PROPERTIES FOR IMPACT RESISTANCE AND STORAGE STABILITY

The present invention relates to emulsion explosives used in the open-air and tunnel blasting site, and more particularly, it is flexible and flexible foam support agent used in emulsion explosives in order to enhance impact resistance by external impact and improve stability by long-term storage. It is an emulsion explosive applied to a plastic shell (Thick shell Plastic Micro Balloon: hereinafter referred to as "PMB") that is elastic, not easily broken, excellent in chemical resistance and thickened.

Bubble preservatives are materials that form a space in the gunpowder with air or other gas.Sensitizer that generates high heat by adiabatic compression when explosives explode and keeps explosives stable. Do it. That is, the emulsion that emulsifies the oxidant solution composed of ammonium nitrate, sodium nitrate, water, etc., and the fuel solution composed of wax, mineral oil, etc. with an emulsifier has no detonation. There are two ways to add bubbles to the emulsion explosive. One is to add a pre-made spherical bubble support agent and the other is to add a substance that generates gas by chemically reacting. Typical examples of the former include glass micro balloons (called "GMB"), perlite, and plastic microspheres (PMB).

The reason why the emulsion explosives should be strengthened the impact resistance by the external impact is to prevent the explosive force of the explosives exploded at the time of delayed blasting affecting the explosives of the adjacent holes to prevent dead pressure and unexplosion. This phenomenon mainly occurs in tunnel blasting where space gap is relatively narrow. The reason why the emulsion explosives remain unexploited due to external impacts is, firstly, the dead-pressure phenomenon caused by the breakdown of the bubble retaining agent due to impact, gas pressure, and rock pressure. Pressure can precede the explosive velocity of explosives, which can be divided into channel effect which impacts unreacted explosives and destroys the bubble retainer. The increase in the proportion of them, the loss of detonation.

Conventionally, there is a method of using a high-strength foam retainer, a method of adding a preservative, a method of adding a buffer, and a method of adding a lot of foam retainers as a method for solving the problem of fire caused by dead pressure. The method of using high-strength foam support was published in the journal "Rugged Emulsion Explosive Formulation # 37" (Thomas C. Rue and Michael S. Wieland), a paper published by the International Society of Explosives Engineers (ISEE), with 0.15 GMB The impact resistance was further enhanced by increasing the strength by increasing the strength of the bulbs by increasing the thickness from -0.20 g / cc to 0.25 g / cc. However, in this method, due to the nature of the emulsion explosives, the density of which must be lowered to maintain the sensitivity of the detonation, the use of a large amount of GMB is inevitable, which leads to an increase in the manufacturing cost. Can be reduced. A method of adding a preservative has been disclosed in US Pat. No. 5,53,665,71 (November 22, 1994) and the like, and the impact resistance is enhanced by adding a pretreatment agent of a nitro compound or an ester compound such as monomethylamine nitrate (MMAN) and hydrazine nitrate (HN). . However, in this method, although the sensitivity decrease due to precompression is relatively small, safety problems may occur when using the preservative in the manufacturing process. The method of adding a buffer material was disclosed in Japanese Patent No. 6-37344 (May 18, 1994), and the impact resistance was enhanced by inserting a buffer material having a large absorbing effect of impact energy. However, this means that these buffers are predominantly carbonaceous, which means that additional fuel is added in addition to the continuous and fuel wax, which is limited to specific applications and may not be suitable for general blasting applications. There is this.

In addition, a method of adding a large amount of foam retaining agent was disclosed in Japanese Patent No. 8-295589 (November 12, 1996). The low-strength microspheres have a compressive strength of 200 to 300 psi and at least 4% of them in the explosive composition. Increased compression resistance and enhanced impact resistance.

However, this method has a disadvantage in that the explosive effect is lowered because the useful energy of the explosive is lowered by lowering the specific gravity of the explosive.

Emulsion explosives, on the other hand, must maintain adequate long-term storage stability, taking into account expiration dates.

The glass micro-balloon (GMB) is the best among the existing bubble support agents, and has a storage stability of about 1 to 2 years. However, existing PMBs have long-term storage properties. It has been used only in bulk emulsions which can be used immediately due to its low long term storage stability of 1 to 6 months. The reason why GMB has excellent storage stability is that the component is silicon oxide (glass main component), which is an inorganic substance of inert substance. However, PMB is an organic substance composed of carbon, hydrogen, oxygen, etc., which is weak in physical (heat, etc.) and chemically, and thus the degree of change is easier.

The present invention has been made in view of the above problems, the vinyl diene chloride (VDC), acrylonitrile (ACN), methyl methacrylate containing 50% or more of acrylonitrile (ACN) excellent in chemical resistance of the material of PMB A copolymer of acrylate (MMA) or polymer of acrylonitrile (ACN) was used, and the average thickness of the shell was increased from 0.1 micron to 0.2 micron or more to enhance the impact resistance of the explosive, as well as the long term. It is to provide explosives that increase storage stability from one to six months to more than one year.

The present invention for achieving the above object,

In water-in-oil emulsion explosives consisting of aqueous oxidant solution, carbonaceous solution, emulsifier, and microspheres, the specific gravity is 0.04-0.1 g / cc, the average particle diameter is 20-100 micron, the average thickness is 0.2-10 micron It consists of a water-in-oil emulsion explosive containing plastic microspheres containing active or inert gas.

The aqueous oxidant solution is composed of ammonium nitrate, sodium nitrate, sodium chlorate, sodium perchlorate, monomethylamine nitrate, hydrazine nitrate, water, and the like. The carbonaceous solution is selected from the group consisting of wax, mineral oil, and diesel oil. . Alternatively, a chemical preservative and Al may be used. The chemical preservative may use a nitro compound or ester compound, such as monomethylamine nitrate (MMAN), hydrazine nitrate (HN). As an emulsifier, SMO (Sorbitan monoleate), PIBSAamine salt (Amine salt of Polyisobutylene succinicanhydride) and the like can be used conventionally, there is no particular limitation.

In the microspheres, the microspheres are required to be polymerized with monomers having excellent chemical resistance in order to enhance impact resistance and improve long-term storage. For such excellent chemical resistance, vinyl diene chloride (VDC), acrylonitrile (ACN), a copolymer of methyl methacrylate (MMA), or a homopolymer of acrylonitrile (ACN) may be used. In a copolymer, it is preferable to contain 50 weight% or more of acrylonitrile.

In addition, for the above impact resistance and long-term storage, it is preferable that the thickness of the shell of the foamed PMB is thicker than the conventional GMB. More preferably, the average thickness of the PMB is 0.2 to 0.4 microns. If the thickness is low, impact resistance and storage stability are lowered. The PMB for chemical resistance and storage stability has a specific gravity of 0.04-0.1 g / cc for the role of hot spot (hot spot: sustained explosion by adiabatic compression) when used as bubble support agent, and the average diameter of particles is 20- It is more preferable to use 100 microns.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples. The following Examples are only described to facilitate the practice of the present invention, and are not described to limit the invention.

EXAMPLE

Hereinafter, an embodiment of the present invention will be described as follows, and the composition and technology for forming an emulsion by emulsifying the oxidizing agent solution and the fuel solution with the emulsifier are generalized, and thus it will be omitted. However, the impact resistance and long-term storage stability are enhanced. Only test results based on the amount of PMB used to make these measurements will be presented.

｝ Composition of Example｝

Note 1 PMB1 in the above table is a foam of 0.1 micron of VDC, ACN, MMA copolymer containing 40% of ACN, and PMB2 is 0.2% of copolymer of ACN, VDC, MMA containing 50% or more of ACN. It is foamed with micron and PMB3 is foamed with 0.3 micron thickness of ACN polymer.

<Note 2> Underwater Waning Distance Test Method

28 mm dynamite (dose 125g) and emulsion explosives (32mm, 250g) made in the composition of the test example were placed in parallel at a distance of 2m depth, and then installed in parallel with a delay time of 20ms, 100ms, 200ms and 500ms. When explosives are used, the distance where the explosives of the emulsion explode is not unexploded even in the pressure of dynamite (3 times in all three times) is considered as the underwater full distance. This underwater descent distance indicates the degree of impact resistance of the explosive, and the closer it is, the better the impact resistance is.

When using GMB K-25 (product of 3M's true specific gravity of 0.25), long-term storage stability is excellent for more than 12 months, but the impact resistance is insufficient at 20,100,200,500ms at 0.4, 0.4, 1.0, 1.0m, respectively. PMB1 has better impact resistance than GMB (K-25) only at 200,500ms but no difference at 20,100ms. Shelf life is too short with a long-term storage stability of 6 months or less, so it can be used for other than bulk emulsion. Is very difficult. On the other hand, PMB2 and PMB3 have not only good impact resistance but also long term storage stability of more than 1 year.

The above is a summary of the underwater waning distance and long-term storage stability according to the bubble preservation system.

As described above, the present invention using PMB provides a water-in-oil emulsion explosive having a high impact resistance in the blast extraction of a tunnel having a short space distance and having a long shelf life in consideration of the expiration date.

Claims (5)

In water-in-oil emulsion explosives consisting of oxidizing agent solution, carbonaceous solution, emulsifier, and microspheres, The microspheres have a specific gravity of 0.04-0.1 g / cc, an average particle diameter of 20-100 microns, an average thickness of 0.2-10 microns, and are plastic microspheres containing active or inert gas therein. Water-in-oil emulsion explosives. The method of claim 1, wherein the plastic micro-spheres are copolymers of vinyl diene chloride (VDC), acrylonitrile (ACN), methyl methacrylate (MMA) containing at least 50% by weight of acrylonitrile (ACN) or A water-in-oil type emulsion explosive, characterized in that it is a foamed plastic comprising a polymer of acrylonitrile (ACN). The water-in-oil emulsion of claim 1, wherein the oxidant aqueous solution is at least one selected from the group consisting of water, ammonium nitrate, sodium nitrate, sodium chlorate, sodium perchlorate, monomethylamine nitrate, and hydrazine nitrate. Explosives. The water-in-oil emulsion explosive according to claim 1, wherein the carbonaceous solution is selected from the group consisting of wax, mineral oil and light oil. The water-in-oil emulsion emulsion according to claim 1, wherein the water-in-oil emulsion explosive further comprises a chemical preservative or Al.