JP2019031413A - Water-in-oil emulsion explosive - Google Patents

Abstract

To provide a water-in-oil emulsion explosive that accommodates mechanical loading, where the water-in-oil emulsion explosive has excellent load bearing capacity and initiation sensitivity against a time-dependent change.SOLUTION: A water-in-oil emulsion explosive has a coating layer of a cured product (B) of (A) an active energy ray-curable resin on the surface of the water-in-oil emulsion explosive composition. Relative to the total mass of the water-in-oil emulsion explosive, the proportion of the cured product (B) of the active energy ray-curable resin is 0.01-5 mass%.SELECTED DRAWING: None

Description

  The present invention relates to a water-in-oil emulsion explosive widely used in industrial blasting operations such as tunneling, quarrying and mining.

  As explosives used for industrial blasting work, nitrate oil explosives (ANFO explosives), dynamite, Ammon explosives, hydrous explosives, etc. are used. Among these explosives, the hydrous explosive in the form of a water-in-oil emulsion is superior in handling safety compared to conventional colloidal dynamite because the explosive component is not included in the composition. Use is widespread. One of the blasting operations is the blasting of tunnel excavation. At the blasting site, loading of explosives often relies on human power. Since it is a close contact work with a dangerous face where there are many falling rock accidents, etc., the worker may be exposed to danger. In addition, loading work by human power takes time, and the cost performance of the entire blasting work is poor. Therefore, there is an increasing demand for machine loading work in order to reduce the burden on the worker and improve work efficiency by blasting long holes. ANFO explosives have been mechanized for loading by a loading machine (ANFO loader). However, the ANFO is dissolved in water at the place of spring water, so that the prescribed explosive performance cannot be obtained, It has drawbacks such as bad things.

  In the case of granular hydrous explosives, measures are also taken for machine loading. Patent Document 1 discloses a water-in-oil emulsion explosive obtained by emulsifying and dispersing an aqueous oxidizing agent solution and fine hollow spheres in a continuous phase of microcrystalline wax dissolved in an ethylene vinyl acetate copolymer using an emulsifier. ing. In this technique, since the resin is cured by heat, an explosive having an appropriate strength can be obtained and molded into a predetermined shape. However, when a load is applied, the stickiness of wax mainly composed of petroleum hydrocarbons and solidification of explosives due to stickiness are not completely improved.

In Patent Document 2, a water-in-oil emulsion explosive composition comprising a discontinuous phase that is an oxidizing agent, an organic phase that is a continuous phase, and at least one polymer that includes an associative functional group that is soluble in the organic phase. Things are disclosed. However, even if a part of the wax is associated, the solution to the problem still cannot be obtained.
As described above, there is a need for a water-in-oil emulsion explosive that has water resistance, prevents deformation and solidification of the explosive, and has good mechanical loadability.

JP 2003-246694 A European Patent Application No. 0276934

  An object of the present invention is to provide a water-in-oil emulsion explosive with good load resistance and explosive properties due to changes over time as a water-in-oil emulsion explosive compatible with machine loading.

As a result of intensive studies to solve the above problems, the present inventors have found that a water-in-oil emulsion explosive having a coating layer of a cured product of an active energy ray curable resin on the surface solves the above problems. The present inventors have found knowledge and have completed the present invention.
That is, the present invention is the following [1].

[1] A water-in-oil emulsion explosive having a coating layer of a cured product (B) of an active energy ray-curable resin on the surface of a water-in-oil emulsion explosive composition (A), A water-in-oil emulsion explosive in which the ratio of the cured product (B) of the active energy ray-curable resin to the total mass is 0.01 to 5 mass%.

  The water-in-oil emulsion explosive of the present invention is an explosive with improved deformation and solidification of the explosive during long-term storage. As a result, it is possible to cope with machine loading of explosives, reduce the loading work in the vicinity of the dangerous face, reduce the burden on the operator, and satisfy the improvement in work efficiency.

Hereinafter, the present invention will be described in detail.
The water-in-oil emulsion explosive of the present invention has a coating layer of a cured product (B) of an active energy ray-curable resin on the surface of a water-in-oil emulsion explosive composition (A).
(Water-in-oil emulsion explosive composition (A))
The water-in-oil emulsion explosive composition (A) used as a conventionally well-known water-in-oil emulsion explosive can be used for the water-in-oil emulsion explosive of this invention without a restriction | limiting. Specifically, it contains, as essential components, a continuous phase composed of oils, a dispersed phase composed of an oxidizing agent aqueous solution, an emulsifier that emulsifies oils and an oxidizing agent aqueous solution, and micro hollow spheres that improve explosive sensitivity.

<Oil>
The oils include all those used in conventionally known water-in-oil emulsion explosives, and are not particularly limited as long as they are water-insoluble. For example, paraffinic hydrocarbons, olefinic hydrocarbons, naphthenic hydrocarbons, aromatic hydrocarbons, saturated or unsaturated hydrocarbons, petroleum refined mineral oils, lubricating oils, hydrocarbons such as liquid paraffin, carbons such as nitro hydrocarbons Waxes such as hydrogen derivatives, fuel oil and petroleum-derived unrefined or refined microcrystalline wax, paraffin wax, mineral wax montan wax, animal wax, whale wax, insect wax, beeswax, etc. Examples thereof include polyethylene wax which is a synthetic wax. These oils can be used individually or in mixture of 2 or more types. If necessary, polybutene, polyisobutylene, vinyl acetate and the like can be added.

  The blending ratio of oils in the water-in-oil emulsion explosive composition (content, in the case of a composition containing fine hollow spheres, is a numerical value that excludes this and is 100% by mass) is usually 0. 0.1 to 10% by mass, preferably 1 to 5% by mass. When the blending ratio of the oil is less than 0.1% by mass, the stability of the water-in-oil emulsion explosive composition is deteriorated. On the other hand, when the blending ratio of oils exceeds 10% by mass, the explosion power tends to decrease.

<Oxidizing agent aqueous solution>
As the oxidizing agent aqueous solution, all those used in conventionally known water-in-oil emulsion explosives can be used without particular limitation. Oxidizing agents include alkali metals such as ammonium nitrate, sodium nitrate, and calcium nitrate, nitrates of alkaline earth metals, inorganic perchlorates such as ammonium perchlorate and sodium perchlorate, hydrazine nitrate, monomethylamine nitrate, etc. And a functional amine nitrate. These oxidizing agents can be used alone or in admixture of two or more. Of the above oxidizing agents, ammonium nitrate alone or a mixture of ammonium nitrate and another oxidizing agent is preferred because it has a low melting temperature and a large amount of dissolution.

  The mixing ratio of the oxidizing agent in the water-in-oil type emulsion explosive composition (content, in the case of a composition containing fine hollow spheres, is a numerical value that excludes this is 100% by mass) is usually 65. It is -90 mass%, Preferably it is 75-85 mass%. When the blending ratio of the oxidizing agent is less than 65% by mass, the explosion power becomes weak. On the other hand, if the blending ratio of the oxidizing agent exceeds 90% by mass, the temperature when forming the water-in-oil emulsion explosive becomes high, which is not suitable for on-site production.

  The oxidizing agent aqueous solution is prepared by dissolving the oxidizing agent in water to form an oxidizing agent aqueous solution. The aqueous oxidizer solution is dispersed in oils as a continuous phase when the water-in-oil emulsion explosive composition is produced, and becomes fine dispersed droplets. Thereby, the specific surface area of oxidizing agent aqueous solution increases, and a contact area with oil becomes large. The content of water only excluding the oxidizer is not particularly limited as long as it functions as a water-in-oil emulsion explosive, but considering the reactivity of the water-in-oil emulsion explosive composition, the crystal of the aqueous oxidizer solution It is preferable to add so that the precipitation temperature is 70 to 95 ° C. In this case, the water content may be 5 to 15% by mass in the water-in-oil emulsion explosive composition. Moreover, the mixture ratio (content) which occupies in the water-in-oil emulsion explosive composition as oxidizing agent aqueous solution is 70-98 mass% normally, Preferably it is 85-95 mass%.

<Emulsifier>
The emulsifier is not particularly limited as long as it includes all conventionally used water-in-oil emulsion explosives and is a nonionic surfactant. Nonionic surfactants include, for example, sorbitan monolaurate, sorbitan monooleate, sorbitan monopalmitate, sorbitan monostearate, sorbitan sesquioleate, sorbitan diolate, sorbitan trioleate, sorbitan fatty acid esters, stearic acid monoglyceride, etc. And mono- or diglycerides of fatty acids such as polyoxyethylene sorbitan fatty acid esters, oxazoline derivatives, imidazoline derivatives, phosphate esters, fatty acid alkali metal salts or alkaline earth metal salts, primary, secondary or tertiary amine salts, etc. . These emulsifiers can be used alone or in admixture of two or more. Of the emulsifiers, sorbitan fatty acid esters are preferred from the viewpoint of the stability of the emulsion structure.

  The blending ratio of the emulsifier in the water-in-oil emulsion explosive composition (content, in the case of a composition containing fine hollow spheres, is a numerical value with 100% by mass excluding this). It is 7 mass%, Preferably it is 1.5-4 mass%. When the blending ratio of the emulsifier is less than 1% by mass, formation of the emulsion structure becomes difficult. On the other hand, if the blending ratio of the emulsifier exceeds 7% by mass, the explosion power may be reduced.

<Micro hollow sphere>
As the micro hollow spheres, all those conventionally used in known water-in-oil emulsion explosives can be used without particular limitation. Examples of the fine hollow sphere include inorganic fine hollow spheres obtained from glass, alumina, shale, shirasu, quartz sand, volcanic rock, sodium silicate, borax, pearlite, obsidian, etc., carbonaceous matter obtained from pitch, coal, etc. Examples include micro hollow spheres, and synthetic resin micro hollow spheres obtained from phenol resin, polyvinylidene chloride, polystyrene, urea resin, and the like. These micro hollow spheres can be used alone or in admixture of two or more.

  The average particle diameter of the micro hollow sphere is usually 0.5 to 100 μm, preferably 10 to 80 μm, more preferably 30 to 70 μm. Further, the blending ratio of the fine hollow spheres in the water-in-oil emulsion explosive composition (the content is a numerical value that makes the composition excluding the fine hollow spheres 100 mass%) is the fine hollow spheres to be used. Although it depends on the specific gravity and the like, it is usually 0.1 to 7% by mass, preferably 1 to 6% by mass. If the average particle size or content of the fine hollow spheres is out of the above range, the explosion sensitivity may be reduced or the explosion power may be reduced.

<Exothermic agent>
As mentioned above, although the essential compounding component was demonstrated in this invention, the exothermic agent (reducing agent) for improving an explosion power can also be added as another additive. As the exothermic agent, all conventionally used water-in-oil emulsion explosives can be used without any particular limitation. For example, metal powder such as aluminum or magnesium having an average particle diameter of usually 10 to 1000 μm. Is mentioned. These exothermic agents can be used alone or in admixture of two or more. In this case, the blending ratio (content) of the exothermic agent in the water-in-oil emulsion explosive composition is usually 0.01 to 30% by mass, preferably 1 to 10% by mass. The greater the amount of the exothermic agent added, the more the explosion power tends to be improved. However, when the proportion of the exothermic agent exceeds 30% by mass, there is a possibility that the explosive power may be lowered.

(Cured product of active energy ray curable resin (B))
The water-in-oil emulsion explosive of the present invention can be obtained by molding into a predetermined shape, coating the surface of the explosive with an active energy ray curable resin, and curing it. By adopting a shape that can be sent out by air and loaded into the drilling hole, it becomes possible to cope with mechanization of loading work.
Water-in-oil emulsion explosives are soft and clay-like in nature and are easily sticky because they are covered with oil. Therefore, when a load is applied to the explosive, deformation and solidification occur due to softness and stickiness, and the explosives agglomerate. As a result, mobility and loadability are affected, such as not passing through the loader hose. Moreover, since the collapse of the emulsion structure is promoted by the load, the explosive performance is lowered. Therefore, it is necessary to coat the explosive surface in some way to protect the explosive and suppress solidification and deformation.

  Examples of the active energy ray curable resin used in the present invention include ene / thiol type, urethane acrylate type, epoxy acrylate type, silicon acrylate type, acrylic acrylate type and ester acrylate type, preferably ene / thiol type and urethane acrylate type. , Epoxy acrylate type, and silicon acrylate type. However, the present invention is not limited to this, and all substances that can be cured by irradiation with active energy rays can be used. According to the present invention, the active energy ray-curable resin is cured by irradiation with active energy rays to form a film, and has toughness and flexibility. Moreover, since the thickness of the film | membrane after hardening increases by adjusting the quantity of resin, a shape is hold | maintained even if a load is applied. By coating such a resin on the surface of a water-in-oil emulsion explosive, load resistance is provided. As a result, solidification and deformation of the explosive can be suppressed.

<Manufacturing method>
As a method for producing a water-in-oil emulsion explosive, all methods conventionally used as a method for producing this type of water-in-oil emulsion explosive can be used without particular limitation. Specifically, an oxidizing agent aqueous solution is obtained by dissolving an oxidizing agent in water at about 85 to 95 ° C. Next, an aqueous oxidizer solution is gradually added to a mixture of oils and emulsifier heated to about 85 to 95 ° C. with sufficient stirring to form a water-in-oil emulsion. Next, other components such as micro hollow spheres are added to the obtained water-in-oil emulsion and mixed with a mixer to obtain a water-in-oil emulsion explosive composition.

The water-in-oil emulsion explosive composition is formed into a predetermined shape while being extruded by an extrusion molding machine or the like, and then an active energy ray curable resin is applied, and the resin is cured by irradiating active energy rays. . All methods for obtaining the water-in-oil emulsion explosive can be used without particular limitation.
In the present invention, the ratio of the cured product (B) of the active energy ray-curable resin to the total mass of the water-in-oil emulsion explosive is 0.01 to 5% by mass, preferably 0.05 to 3% by mass. Preferably it is 0.1-2 mass%. When the ratio is too small, the strength of the film after curing is weak, so that the load resistance becomes poor. If it is too much, the gas becomes worse. The “ratio of the cured product (B) of the active energy ray curable resin” in the present invention means a numerical value calculated by the application amount of the active energy ray curable resin.

  The coating method is not particularly limited, and any known method such as a roll coating method, a spin coating method, a dip coating method, a spray coating method, a bar coating method, a knife coating method, a die coating method, an ink jet method, a gravure coating method, etc. Can also be adopted. The type of active energy ray is not particularly limited, but it is preferable to use ultraviolet rays from the viewpoint of convenience and the like.

The water-in-oil emulsion explosive thus obtained may be used after being formed into an appropriate shape. Specific examples include the following (a) or (b).
(A) A spherical shape having a diameter of 5 to 30 mm and an explosive weight per piece of 0.08 to 20 g.
(B) Explosive weight per piece in a columnar shape having a length of 10 to 200 mm, a cross-sectional diameter of 10 to 30 mm, and a ratio of the length to the cross-sectional diameter (length / cross-sectional diameter) of 0.3 to 20 Is 0.8 to 170 g.
In the case of a spherical shape, the size and weight of the explosive per piece are preferably 11 to 30 mm in diameter, and 0.75 to 17 g per explosive weight, more preferably 15 to 30 mm in diameter. The explosive weight per piece is 1.9 to 17 g.
On the other hand, in the case of a cylindrical shape, the size and weight of explosive per piece are preferably 30 to 170 mm in length, 11 to 30 mm in cross section diameter, and ratio of length to cross section diameter (length / cross section diameter). Is 1 to 15.5, the explosive weight per piece is 3 to 145 g, more preferably the length is 35 to 150 mm, the cross-sectional diameter is 15 to 30 mm, and the ratio of the length to the cross-sectional diameter (length / The diameter of the cross-section) is 1.1 to 10, and the explosive weight per piece is 6 to 130 g. Here, the “cross section” means a cross section perpendicular to the length direction.

The present invention will be specifically described below with reference to examples.
First, the evaluation method in each example is shown.

[Load resistance]
About 20 kg of the water-in-oil emulsion explosive obtained in each Example and Comparative Example was placed in a cardboard box and allowed to stand at room temperature for 1 year. The deformation of the explosive after storage for one year was confirmed. Moreover, the test which confirms load resistance simply was implemented. 400 g of the water-in-oil emulsion explosive obtained in each of the examples and comparative examples was put in a transparent container with an inner diameter of φ80 mm, and a constant load of 0.02 kg / cm ² was applied from the top and left in a constant temperature bath at 40 ° C. for 1 week. did. One week later, the container was taken out, and the deformation of the explosive was confirmed.
○ “No deformation” △ “With or without deformation”
[Low-temperature initiation sensitivity test]
The temperature of the water-in-oil emulsion explosive obtained in the examples and comparative examples is adjusted to −25 ° C., and a No. 6 instantaneous electric detonator is attached to the booster for initiation. Whether or not the explosive has been completely detonated is determined by the presence or absence of a hole in the evidence board, using an evidence board to leave a trace of the detonation reaction. Judgment criteria are as follows.
○ “It was completely detonated” × “It was unexplosive”

<Preparation of water-in-oil emulsion explosive composition>
A water-in-oil emulsion explosive composition was prepared with the composition shown in Table 1.
As a method for producing a water-in-oil emulsion explosive composition, all methods conventionally used as a method for producing this type of water-in-oil emulsion explosive composition can be used without particular limitation. Specifically, an oxidizing agent aqueous solution is obtained by dissolving an oxidizing agent in water at about 85 to 95 ° C. Next, an aqueous oxidizer solution is gradually added to a mixture of oils and emulsifier heated to about 85 to 95 ° C. with sufficient stirring to form a water-in-oil emulsion. Next, micro hollow spheres are added to the obtained water-in-oil emulsion and mixed with a mixer to obtain a water-in-oil emulsion explosive composition. In addition, in order to obtain the water-in-oil type emulsion explosive, the emulsion explosive composition is cut into a predetermined shape while being extruded by an extrusion molding machine or the like, and an active energy ray curable resin is applied to the surface of the explosive composition. It is obtained by irradiating a wire to cure the resin. Moreover, not only the said manufacturing method but all the methods of obtaining the active energy ray hardening resin-coated water-in-oil emulsion explosive shape | molded by the predetermined shape can be especially used without a restriction | limiting.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples and comparative examples, but the present invention is not limited to these examples. The basic composition of the water-in-oil emulsion explosive composition excluding the fine hollow spheres is 100 parts by mass, and the fine hollow spheres are externally divided.

Example 1
First, it melt | dissolved by adding in addition to 77.1 mass parts of ammonium nitrate and 5.67 mass parts of sodium nitrate, and 11.78 mass parts of water as an oxidizing agent, and obtained about 90 degreeC oxidizing agent aqueous solution. On the other hand, 2.71 parts by mass of a wax composed of petroleum hydrocarbons having a melting point of 80 ° C. as oils, and sorbitan monooleate having a hydrophilic / lipophilic balance (HLB) of 4 as an emulsifier (non-water for water-in-oil emulsions) 2.74 parts by mass of ionic surfactant) was heated and melt-mixed to obtain a combustible mixture.

  Next, 5.45 parts by mass of a combustible mixture is first put in a container capable of keeping warm, and 94.55 parts by mass of an oxidant aqueous solution is gradually added thereto, while using a commonly used propeller blade type stirrer at about 600 rpm. Mixing and stirring were performed to obtain 100 parts by mass of a coarse emulsion. Subsequently, the rotation speed of the stirrer was increased to about 1600 rpm, and the mixture was stirred for 3 minutes to obtain a water-in-oil emulsion at about 85 ° C. Finally, 4.00 parts by mass of glass microballoons as fine hollow particles and the water-in-oil emulsion are mixed at about 30 rpm using a vertical mixer to obtain a water-in-oil emulsion explosive composition (A ) After extruding the water-in-oil emulsion explosive composition from an extrusion molding machine having a nozzle diameter of 20 mm, it was molded into a spherical shape. An epoxy acrylate-type active energy ray-curable resin is applied to the surface of the water-in-oil emulsion explosive composition so that the amount is 0.1% by mass with respect to the mass of the explosive, and then the resin is cured by irradiating ultraviolet rays. Prepared (Example 1).

(Example 2)
A water-in-oil emulsion explosive composition (A) was obtained under the same conditions and procedures as in Example 1. After extruding the water-in-oil emulsion explosive composition (A) from an extrusion molding machine having a nozzle diameter of φ10 mm, it was cut to a length of 20 mm. The surface of this water-in-oil emulsion explosive composition was prepared by applying 0.5% by mass of a silicon-type active energy ray curable resin to the mass of the explosive, and then irradiating ultraviolet rays to cure the resin (implementation) Example 2).

(Example 3)
A water-in-oil emulsion explosive composition (B) was obtained under the same conditions and procedures as in Example 1 except that 3.00 parts by mass of glass microballoons of fine hollow particles were mixed. After extruding the water-in-oil emulsion explosive composition (B) from an extrusion molding machine having a nozzle diameter of 25 mm, it was cut to a length of 60 mm. On the surface of this water-in-oil emulsion explosive composition, an en-thiol-type active energy ray-curable resin is applied at 1.0% by mass with respect to the mass of the explosive, and then the resin is cured by irradiating ultraviolet rays. (Example 3).

Example 4
A water-in-oil emulsion explosive composition (C) was obtained under the same conditions and procedures as in Example 1 except that 5.50 parts by mass of glass microballoons of fine hollow particles were mixed. After extruding the water-in-oil emulsion explosive composition (C) from an extrusion molding machine having a nozzle diameter of 30 mm, it was cut to a length of 150 mm. After applying a urethane acrylate type active energy ray curable resin to the surface of this water-in-oil emulsion explosive composition so as to be 1.8% by mass with respect to the mass of the explosive, the resin is cured by irradiating with ultraviolet rays. Prepared (Example 4).

(Comparative Example 1)
A water-in-oil emulsion explosive composition (A) was prepared under the same conditions and procedures as in Example 1. After extruding the water-in-oil emulsion explosive composition from an extrusion molding machine having a nozzle diameter of φ20 mm, it was molded into a spherical shape and produced without applying an active energy ray-curable resin (Comparative Example 1).

(Comparative Example 2)
A water-in-oil emulsion explosive composition (B) was obtained under the same conditions and procedures as in Example 3. After extruding the water-in-oil emulsion explosive composition from an extrusion molding machine having a nozzle diameter of φ25 mm, the composition was cut to a length of 60 mm without applying an active energy ray-curable resin (Comparative Example 2).
The composition of each example and comparative example is summarized in Table 1. In addition, the numerical value in Table 1 is a mass part.

  With respect to the water-in-oil emulsion explosives obtained in each of Examples and Comparative Examples, load resistance and initiation properties were confirmed. Each test was tested as follows.

As is apparent from the results in Table 2, Examples 1 to 4 were substantially good in terms of mobility and loadability, with only a little catching in the hose. Solidification of the explosive was remarkably suppressed by the film after curing with the active energy ray curable resin. On the other hand, in Comparative Examples 1 and 2 that were not coated with the active energy ray curable resin, the explosives were significantly solidified and agglomerated. It is thought that it was solidified by the softness and stickiness of the explosive.

Claims (1)

A water-in-oil emulsion explosive having a coating layer of a cured product (B) of an active energy ray-curable resin on the surface of a water-in-oil emulsion explosive composition (A), the total amount of the water-in-oil emulsion explosive A water-in-oil emulsion explosive in which the ratio of the cured product (B) of the active energy ray-curable resin is 0.01 to 5% by mass.