JPS582195B2 - Water-in-oil emulsion explosive composition - Google Patents

Description

Detailed Description of the Invention The present invention uses an oxyethylene oxypropylene block copolymer as an emulsifier to produce a water-in-oil type (hereinafter referred to as W/0 emulsion explosive compositions (referred to as molds).

Conventionally, in order to improve the explosive reactivity (the characteristic value of which is generally represented by the detonation velocity) of general explosives, the following steps have been taken: ■ Selection of each component of the explosive composition, and ■ Mixing of each component of the explosive composition. This has been done by considering each of the following: changing the state.

In the case of (2) above, means to increase the reactivity of the explosive composition include selecting a substance with a high reaction rate, and selecting a substance that generates a large amount of heat during reaction, that is, a substance with high explosion heat.

In addition, in the case of (1) above, the oxidizer and fuel come into contact with each other in the form of fine particles in order to increase the reactivity of the mixed system;
That is, the contact area can be increased by increasing the contact area or by mutually dissolving through water.

Therefore, when a water-containing explosive contains a water-soluble substance and a water-insoluble substance, it is very difficult to bring them into contact through water in a dissolved state. It is necessary to form a mixed system in which both are in the form of particles and have an increased contact area.

Most conventional hydrous explosive compositions are so-called oil-in-water type (hereinafter referred to as O/W type) emulsion explosives, in which the main component, water, envelops water-insoluble substances or residual water-soluble substances that cannot be dissolved in water. It was a composition.

Most of the water-soluble substances in this O/W type emulsion explosive composition are oxidizing agents, such as inorganic oxide salts such as ammonium nitrate, and most of the water-insoluble substances are fuel or sensitizers that also serve as fuel. , such as aluminum, nitromethane, etc.

Generally, in a hydrous explosive composition, its components are divided into a water-insoluble substance (denoted as O) and a water-soluble substance (denoted as W),
Looking at the weight ratio, the O/W is generally 25/75.
It is as follows.

Therefore, if we consider that the particle diameters dispersed in O/W emulsion and W/O emulsion are the same, the contact area between O and W is so-called that the smaller amount of O envelops the larger amount of W. W/O type emulsion is larger than O/W type emulsion.

Therefore, W/0 type emulsions are expected to have improved explosive reactivity, and as a result, it is possible to obtain explosives with less smoke and good aftergas.

Therefore, from the viewpoint of increasing the contact area, W was used instead of the conventional O/W type emulsion explosive composition.
/O type emulsion explosive compositions have been developed and various have been disclosed as patents.

That is, for example, U.S. Patent Nos. 3,161,551, 3,164,503, and 3,212,945.
65 No. 47, No. 3442727, No. 34479
No. 78, No. 3617406, No. 3674578, No. 3765964,! There are specifications such as No. 3770522 and No. 4008108.

In such a W/O emulsion explosive composition, the quality of the W/O emulsion explosive composition is greatly influenced by the selection of the emulsifier necessary to form the W/O emulsion.

Incidentally, Table 1 shows the emulsifiers used in the W/O type emulsion explosive compositions described in the specifications of each of the above-mentioned US patents.

Although it is known that various emulsifiers are used in this way, most emulsifiers other than sorbitan fatty acid ester have poor emulsion stability over time in the W/O emulsion explosive composition. In addition, the explosive reactivity and low-temperature detonability (detonation ability at low temperatures) were insufficient.

In addition, when sorbitan fatty acid ester is used, emulsion stability over time and explosive performance are good, but sorbitan fatty acid ester is not necessarily composed of a single component in general industrial products, but isomers, polycondensation When used in a W/O emulsion explosive composition, it is difficult to obtain stable performance.

As a result of intensive research over a long period of time while taking into consideration the above-mentioned problems, the present inventors discovered that a substance that had not been previously considered as an emulsifier for W/O emulsion explosive compositions is an inorganic oxidizing acid such as ammonium nitrate. It has been discovered that an aqueous solution of a salt (an aqueous oxidizing agent solution) and an oil can be formed into a W/O emulsion, and the W/O emulsion explosive composition obtained thereby has excellent emulsion stability over time,
It was found that it has properties such as explosive reactivity and low-temperature detonability, and the present invention was completed.

That is, the W/O emulsion M composition of the present invention is
(a) ammonium nitrate or ammonium nitrate and other inorganic oxide salts (hereinafter referred to as inorganic oxide salts such as ammonium nitrate), (b) water, (c) oils, and (d) oxyethylene oxypropylene block copolymer. An emulsion composition comprising an emulsifier (hereinafter referred to as oxyethylene oquine propylene block copolymer) having a molecular weight of 3,000 to 20,000 and an ethylene oxide content of 5 to 70% by weight. It is characterized by containing bubbles generated by the addition of a chemical blowing agent.

Further, the method for producing the W/O emulsion explosive composition of the present invention includes (a) an oxidizing agent aqueous solution in which all or a part of an inorganic oxidizing acid salt such as ammonium scathate is dissolved in water at 55 to 75°C; (b) An oil emulsifier phase solution prepared by mixing oils and the above-mentioned oxyethylene oxypropylene block copolymer (emulsifier) at a temperature of 55 to 75°C, and (c) mixing and stirring at a temperature of 55 to 75°C. As an emulsion composition,
Next, if there is any remaining inorganic oxide salt such as ammonium nitrate that was not added to the oxidizing agent aqueous solution, it is mixed therein, and (e) micro hollow spheres and/or a chemical blowing agent are mixed therein. When added, air bubbles are added to adjust the tentative specific gravity to obtain the desired W/O emulsion explosive composition.

Specific examples of each component used in the present invention are as follows.

That is, other inorganic oxide salts used together with ammonium nitrate include, for example, nitrates such as sodium nitrate and calcium nitrate, chlorates such as sodium chlorate, and perchlorates such as sodium perchlorate.

Examples of the oil include liquid oils such as light oil and heavy oil, and solid oils such as paraffin, and these can be used in various blending ratios depending on the hardness of the desired explosive composition.

The oxyethylene oxypropylene block copolymer as an emulsifier can be obtained by the following method.

That is, an alkali catalyst is added to a predetermined amount of ethylene glycol, heated, and a predetermined amount of ethylene oxide is added dropwise in an autoclave to produce an adduct of ethylene oxide, and then a predetermined amount of propylene oxide is charged to produce propylene oxide. After that, a predetermined amount of ethylene oxide is charged again to obtain an oxyethylene oxypropylene block copolymer.

The molecular weight and ethylene oxide content of the oxyethylene oxypropylene block copolymer can be adjusted by adjusting the amounts of ethylene oxide and propylene oxide charged.

The molecular weight of the oxyethylene oxypropylene block copolymer used in the present invention is 3,000 to 20,000, and the ethylene oxide content is 5 to 70% by weight.

When the molecular weight and the ethylene oxide content are out of this range, the stability over time, low-temperature detonability, and explosive reactivity of the W/O emulsion explosive composition deteriorate.

As the oquine ethylene oxypropylene block copolymer within the above range, there is, for example, the trade name "Pronon 204" manufactured by NOF Corporation.

The molecular weight of the preferred oxyethylene oxypropylene block copolymer is 7,000 to 15,000, and the content of ethylene oxide is 10 to 40% by weight.Also, it can be used as micro hollow spheres and/or a chemical blowing agent (hereinafter referred to as temporary specific gravity adjuster). The following can be used:

Examples of micro hollow spheres include glass micro hollow spheres, synthetic resin micro hollow spheres, silica micro hollow spheres, and shirasu micro hollow spheres. 500 as diameter
Can be used up to the roughness of μ.

Examples of chemical blowing agents include inorganic ones such as alkali metal borohydrides, those using a combination of sodium nitrite and urea, N,N'-dinitrosopentamethylenetetramine, azodicarbonamide azobisisobutyro The blending ratio of each of these components, including nitrile, in a W/O emulsion explosive composition should be determined in consideration of oxygen balance, explosive power, drug quality, manufacturability, etc.

Usually, inorganic oxide salts such as ammonium nitrate have 50 to 9
0% (by weight, same below) Water is 5-20%, oil is 2%
~7%, emulsifier 1-5%, micro hollow spheres 1-10%
The chemical blowing agent is blended in a range of 0.1 to 2%.

Next, the present invention will be specifically explained using Examples and Comparative Examples.

Note that all parts and ratios in each example are based on weight.

In addition, the W/O emulsion explosive compositions obtained in each example were evaluated by temperature cycle aging tests for emulsion stability over time, and detonation tests and explosion velocity measurements for low-temperature detonation and explosive reactivity. I went there.

The method is as follows.

Temperature cycle aging test was kept at 0℃ for 4 hours, then 4 hours.
The temperature was raised to 0° C. and maintained for 7 hours, which was defined as one cycle, and the number of times the emulsion was broken was recorded.

Next, for the detonation test and detonation velocity measurement method, a polyethylene tube with a diameter of 25 mm and a length of 200 mm was loaded with the sample emulsion composition, the end was tightened, the sample was placed in a cryostat, the temperature was adjusted to the test temperature, and the probe was was inserted and detonated with a No. 6 electric detonator on the sand in an open state, and the detonation speed was measured using a digital counter.

Comparative Example 1 A W/O type emulsion explosive composition having the composition shown in Table 2 was manufactured in the following manner according to the manufacturing method described above.

First, 160 parts of ammonium nitrate, 40 parts of sodium nitrate
40 parts of calcium nitrate were added to 36 parts of water and dissolved by heating to prepare an aqueous oxidizing agent solution at about 65°C.

On the other hand, 8 parts of butyl stearate and 14 parts of No. 2 light oil were mixed by heating to prepare an oil emulsifier compatible solution at about 65°C.

Next, the oxidizing agent aqueous solution was gradually poured into the oil emulsifier compatible solution and stirred at about 300 rpm using a commonly used propeller blade type stirrer.
By stirring at pm, an emulsion composition having a temperature of about 65°C was obtained.

Subsequently, 24 parts of glass micro hollow spheres as a temporary specific gravity adjuster were added and mixed to produce a W/O emulsion explosive composition.

The thus obtained W/O type emulsion explosive composition was subjected to a temperature cycle aging test and a detonation test.

The results were as shown in Table 2. Comparative Examples 2 to 9 W/O emulsion explosive compositions having the compositions shown in Table 2 were manufactured according to the manufacturing method described above and in accordance with Comparative Example 1. Temperature cycle aging tests and detonation tests were conducted only on those that had formed emulsions.

However, Comparative Examples 2, 5, and 6 failed to form an emulsion.
, 7, and 9, glass micro hollow spheres were not added (the blending ratio of micro hollow spheres shown in Table 2 was planned to be added at the time of emulsion formation).

Example 1 A W/O emulsion explosive composition having the composition shown in Table 2 was prepared by adding 160 parts of ammonium nitrate, 40 parts of sodium nitrate, and 40 parts of calcium nitrate to water according to the manufacturing method described above. An aqueous oxidizing agent solution of about 65° C. was prepared by adding 36 parts of the oxidizing agent and dissolving it by heating.

On the other hand, oxyethylene oxypropylene block copolymer (molecular weight 7000, ethylene oxide content 30%) 8
and 14 parts of No. 2 diesel oil were mixed by heating to prepare an oil emulsifier compatible solution at about 65°C.

Next, the oxidizing agent aqueous solution was gradually poured into the oil emulsifier compatible solution, and stirred at about 300 rpm using a commonly used propeller blade type stirrer.
The emulsion composition was obtained at about 65° C. by stirring at pm.

Subsequently, 24 parts of glass micro hollow spheres as a temporary specific gravity adjuster were added and mixed to obtain a W/O emulsion explosive composition.

Examples 2 to 7 W/O emulsion explosive compositions having the composition shown in Table 2 were manufactured according to the above manufacturing method (Examples 2 to 7) according to Example 1, and subjected to temperature cycle aging tests. Detonation tests and detonation velocity measurements were conducted.

The results were as shown in Table 2. For Carrying Example 4, after sample preparation, the sample was heated in a constant temperature bath at about 50° C. for 2 hours to decompose and foam the chemical blowing agent (dunitrosopentamethylenetetramine) and to lower the tentative specific gravity.

Note-1) The chemical names of substances (■ to ■) listed in the conventional emulsifier section are as follows.

■ Butyl stearate ■ Potassium stearate ■ Polyoxyethylene octadecylamine ■ Alkyl (coconut oil) phosphate ester ■ Polyoxyethylene monooleate ■ Polyoxyethylene cetyl ether ■ Dodecylbenzenesulfonic acid ■ Alkyl (coconut oil) alkylolamide (2) Phorioxyethylene alcohol Note 2) The chemical names of the substances (1) to (2) described in the section of the emulsifier of the present invention and their manufacturing methods are as follows.

■ It is an oxyethylene oxypropylene block copolymer (molecular weight 7000, ethylene oxide content 30% by weight), which is prepared by adding 5 g of an alkali catalyst (KOH) to 1 mole of ethylene glycol, heating it to 120°C, and placing it in an autoclave. First, 24 moles of ethylene oxide was added dropwise while monitoring the pressure inside the thread, and the mixture was aged for 1 hour to produce an ethylene oxide adduct. Next, 84 moles of propylene oxide was similarly charged and aged for 1 hour to produce propylene. An adduct of ethylene oxide was prepared, and finally, 24 moles of ethylene oxide was added in the same manner as before and aged for 1 hour to produce an adduct of ethylene oxide.■ Oxyethylene oxypropylene block copolymer (molecular weight 10,000, ethylene oxide content 40% by weight), which was produced according to the method (2) above.

However, the initial amount of ethylene oxide charged is 45 moles, the intermediate amount of propylene oxide charged is 103 moles, and the final amount of ethylene oxide charged is 46 moles.■ Oxyethylene oxypropylene block copolymer (molecular weight 15,000, ethylene oxide content 20% by weight), and was produced according to the method (2) above.

However, the initial charge amount of ethylene oxide is 34 moles, the middle charge amount of propylene oxide is 207 moles, and the final charge amount of ethylene oxide is 34 moles. Note 3) Resin micro hollow used here The spheres are phenolic resin micro hollow spheres.

Note-4) Dinitrosopentamethylenetetramine was used as a chemical blowing agent.

Note-5) In the emulsification section, ○ indicates what could be emulsified, and × indicates what could not be emulsified.

Note-6) In the section on temperature cycle change over time, the numbers indicate the number of strokes of the temperature cycle, the ○ symbol indicates that the emulsion is in good condition after that number of temperature cycles, and the × symbol indicates that the emulsion is in good condition after that number of temperature cycles. Indicates that each item has been destroyed.

Note 7) In the section on detonation tests, the upper row indicates the test temperature, the lower row ○ indicates explosion, and × indicates non-explosion.

Note-8) The values in the detonation velocity section are the detonation velocity values obtained when the detonation test in the upper column was conducted.

Next, the results of each comparative example and example will be explained in detail.

Comparative Examples 2, 5, 6, 7, and 9 used potassium stearate, polyoxyethylene monooleate, polyoxyethylene cetyl ether, dodecylbenzenesulfonic acid, and polyoxyethylene alure as emulsifiers, and the manufacturing method was as follows: It was carried out using the manufacturing method described above,
It was not possible to form an emulsion.

Comparative Examples 1, 3, 4, and 8 were carried out by the above-mentioned manufacturing method using butyl stearate, polyoxyethylene octadecylamine, alkyl (coconut oil) phosphate, and alkyl (coconut oil) alkylolamide as emulsifiers. In some cases, an emulsion could be formed.

However, when the above-mentioned temperature cycle aging test was carried out, the emulsion was destroyed after 1 cycle, 1 cycle, and 2 cycles.

When this destroyed emulsion was detonated with a No. 6 detonator at 20°C, it did not explode.

Example 1 was produced by the above-mentioned production method using an oxyethylene oxypropylene block copolymer (molecular weight 7000, ethylene oxide content 30% by weight) as an emulsifier. After running the cycle 30 times, I couldn't find any change in the properties of the emulsion -1
When it was detonated with a No. 6 detonator at 0℃, it exploded with 4230
We were able to obtain a high explosion speed of m/s.

Examples 2, 3, and 4 were produced using the same emulsifier as in Example 1, using resin, each micro hollow sphere of Shirasu, and dinitropentamethylenetetramine as temporary specific gravity adjusters, and using the above-mentioned production method. When temperature cycling was performed on the produced emulsion composition, 30
Even after several times, there was no change in the properties, -10
When it was detonated with a No. 6 detonator at ℃, it exploded and reached 4110 m.
/S, 3510m/S, and 3810m/S were able to be achieved.

The reason why the explosion speed is low when using Shirasu micro hollow spheres is that
This is because the particle size of the whitebait micro hollow spheres is one order of magnitude larger than that of the glass micro hollow spheres.

In Examples 5 and 6, an oxyethylene oxypropylene block copolymer with a molecular weight of 10,000 and an ethylene oxide content of 40% by weight and an oxyethylene oxypropylene block copolymer with a molecular weight of 15,000 and an ethylene oxide content of 20% by weight were used as emulsifiers, respectively. Results equivalent to those of Examples 1 to 4 could be obtained with the products manufactured using the following methods.

In Example 7, the amount of the temporary specific gravity adjuster was reduced, and as a result, the temporary specific gravity of the emulsion explosive composition was naturally high, so the detonation properties at low temperatures were slightly inferior compared to Examples 1 to 6. .

The above Comparative Examples and Examples demonstrate that the composition of the present invention is a W/O emulsion explosive composition that is unprecedented in terms of stability over time, low-temperature detonation properties, and explosive reactivity.

Claims (1)

[Claims] 1 (a) ammonium nitrate or ammonium nitrate and other inorganic oxide salts, (b) water, (c) oils, and (d)
By adding (e) micro hollow spheres and/or a chemical blowing agent to an emulsion composition consisting of an emulsifier that is an oxyethylene oxypropylene block copolymer with a molecular weight of 3,000 to 20,000 and an ethylene oxide content of 5 to 70% by weight. A water-in-oil emulsion explosive composition containing generated air bubbles.