SK285615B6 - Method for brisance modification of explosive in the form of emulsion - Google Patents

Abstract

Method for the brisance modification of the emulsive explosive "water in oil" type by modificative agent consists of macromolecular component comprises pre-polymer or polymer with structural units -[CH2-C (X)=CH-CH2]- in its macromolecule, wherein X is -H or -CH3, which is terminated by hydroxy- or isocya-nate units or polyisobutyl groups. Application of the modificative agent in the emulsive explosive reduces its brisance keeping the same working ability and increasing of the physical stability of this explosive.

Description

The invention relates to the modification of the water-in-oil emulsion explosion by means of a modifying agent consisting of a macromolecular component based on butadiene (liquid rubbers) and / or isobutylene.

BACKGROUND OF THE INVENTION

When we look at water-in-oil emulsion explosives (code name W / O) as a mixture of chemical components, it is an oxidation-reduction system, as with most mixed explosives. The fuel-oxidant mixture is supplemented with a suitable non-explosive sensitizer capable of participating by generating hot cores in the initiation and development of a chemical reaction during detonation.

In most mixed explosives, the basic oxidant is ammonium nitrate, often in combination with other nitrates (eg sodium, potassium, calcium, lithium, etc.), or even perchlorates (sodium or ammonium). A wide, almost opaque palette, especially of carbonaceous compounds of mineral and / or synthetic origin, is used as a fuel (see, e.g., W. Xuguang: Emulsion Explosives. Metallurgical Ind. Press, Beijing, 1994). The most commonly used fuels are paraffin oils and waxes, mineral, petroleum, possibly also vegetable oils, microcrystalline waxes and some petroleum fractions. The choice of a particular fuel or fuel mixture is dictated by the requirements for the rheology of the resulting explosive and its physical and storage stability. In some cases, the fuel phase may also include metal powders (especially aluminum) and individual explosives (demilitarized trinitrotoluene and / or hexogen and demilitarized propulsive explosives).

In conventional W / O emulsion explosives, the oxidation and fuel components are present in a liquid state: the discontinuous oxidant phase in the form of microspheres of a supersaturated solution of oxidants and other water-soluble additives is dispersed in the continuous (oil) phase of the fuel microspheres (oxidant phase). The formation of a continuous and solid interface between the continuous and discontinuous phases is achieved by the addition of lipophilic hydrophilic components to the oil phase, i.e. emulsifiers, of which sorbitan monooleate and / or scsquiol acetate are the most commonly used in the art.

Strengthening of the continuous phase film and thereby enhancing the physical stability of the resulting emulsion (emulsion matrix) can be achieved by adding to the fuel phase some oligomers, polymers and / or copolymers (see e.g. W. Xuguang: Emulsion Explosives. Metallurgical Ind. Press, Beijing, 1994) . In this context, the use of oligomers, polymers and resins based on isobutylene and butadiene is described (see, e.g., Can. Pat. Appl. CA 2,107,966 from 1994, or Jpn. Kokai Tokkyo Koho JP 59,156,991 from 1984): here in particular hydroxy-liquid liquid. polybutadiene has a beneficial effect on enhancing emulsion stability. In the manufacture of these explosives, hydrophilically terminated polyisobutylenes sometimes appear as polymeric emulsifiers, the use of which significantly increases the life of the final product.

The extremely large interfacial interface surfaces in the emulsion explosive matrix ensure perfect contact of both phases, which is the most perfect of all mixed industrial explosives. This corresponds to the short reaction zone in the detonation wave: with suitable sensitivity and initiation, explosives of this type can be considered to be largely equivalent to dynamites, due to the high reactivity of the system, the high utilizable energy yield and the resulting rock disconnection effect.

Compared to dynamites (i.e. explosives containing nitroesters), emulsion explosives have a number of significant advantages, such as insensitivity to mechanical stimuli, flame and sparks, high water resistance and minimal physiological activity not only of the emulsion composition itself, but also of explosion products. Emulsion explosives can, however, be phlegmatized, up to completely numb, by the dynamic shock, in particular a strong compression stress wave, induced by detonation of a near charge in the rock mass. Another disadvantage is the fact that only Category I mining-explosives can be produced on the basis of emulsion explosives. Both of these disadvantages are mainly related to the relatively high brisance (i.e., fragmentation effect) of said type of explosives.

The most widespread principle of designing mining-safe explosives containing nitroesters is to incorporate a cooling additive (most often sodium chloride) or a cooling ion exchange system (e.g., a mixture of ammonium chloride and sodium nitrate) into the explosive mixture. This leads to a decrease in the working ability and the chances of the resulting explosive compared to nitroester explosives without coolants. However, as is apparent from the exemplary part of the present invention, an analogous incorporation of sodium chloride in an amount of max. 10 wt. into an emulsion explosive mixture, while reducing its working ability, but increasing brisance. Thus, the cooling effect of said additive can be eliminated to some extent. The problem of emulsion explosives is a decisive factor in the construction of mining-safe explosives based on them. The data published so far show that a systematic study of the impact of the chemical nature of the components of the redox system of these explosives on their brisance has not been addressed so far.

SUMMARY OF THE INVENTION

According to the present invention, the water-in-oil emulsion explosive is modified by adding to the oil phase of the modifying agent which forms macromolecular components based on butadiene or isobutylene, prepolymer or polymer with building units - [CH ₂ -C (X) = CH-CH ₂ ] - in its macromolecule, wherein X is -H or -CH ₃ , which is terminated by hydroxyl or isocyanate groups or polyisobutylene groups. The advantage is that the relatively small addition of said macromolecular components (0.50 to 1.80% by weight based on the weight of the resulting explosive) will significantly reduce brisance while maintaining the working ability of the emulsion explosive, while significantly increasing its stability and modifying the consistency of the resulting explosive. that, if the coolant is incorporated into its composition, it will provide a Category I mine safety explosive. Another advantage of the brisance modification of the present invention is the availability of these macromolecular components which are manufactured industrially for the needs of the plastics and / or rubber industry, as well as for the production of special types of explosives.

The use of butadiene or isobutylene-based macromolecular components to modify the emissivity of an emulsion explosive according to the present invention has not been described in the literature and is documented by the following examples, which in no way exclude the possible variability of applications.

BRIEF DESCRIPTION OF THE DRAWINGS

The graph illustrates the graphical dependence of the relative working ability (RPS) of the emulsion explosives of Example 1 and Example 2 on their performance, represented by the product of the specific charge mass and the square of the detonation velocity, ie the expression p * D ² .

DETAILED DESCRIPTION OF THE INVENTION

Example 1

A solution of ammonium nitrate (AN) and optionally sodium nitrate (SN) and / or calcium nitrate (CN) and / or sodium perchlorate (SP) in water, having a temperature of 85-100 ° C, optionally containing other water-soluble components such as sodium chloride (SN), glycol, and the like, is impregnated into an emulsifier, in which an intensively mixed (agitator at 1000 to 1500 rpm) oil phase 80-85 ° C warm, consisting of a mineral oil (having a specific weight) 910 kg.m ' ³ , pour point max. -5 ° C and flash point min. 66 ° C) and / or slack wax (pour point 39 ° C, flash point 220 - 260 ° C and oil content about 1.5 % sorbitan monooleate (M) and / or sorbitan sesquioleate (S), optionally also macromolecular components. After the inlet of the aqueous salt solution is complete, the mixture is stirred for a further 5 minutes. The emulsion matrix thus obtained is sensitized in the homogenizer by the addition of silicate microballoons (MB) of an average particle size pm, optionally also by the addition of solid sodium chloride (NaCl) of an average grain size of 80 pm. The resulting explosive mixtures are then loaded into plastics casings to prepare charges of 32 mm diameter and weight of 400 g at which the specific charge mass (p), detonation velocity (D, initiation by detonator No. 8) and relative working ability (RPS) are determined. An overview of the composition of the individual mixtures prepared according to this procedure is given in the table of Example I, which also includes the respective p, D and RPS values.

The following macromolecular components of the oil phase are used:

- liquid polybutadiene rubber (LBH) with hydroxyl end groups having an average molar mass of 2400 - 3100, a polydispersity index of approximately 1.1 and a hydroxyl content of approximately 0.7 mmol.g · ', in which the number of structural units of its macromolecule - [CH ₂ - CH = CH-CH ₂ ] - is about 44 to 57.

- liquid isocyanate prepolymer (LBD - terminated by isocyanatotolylene groups) with a basic polybutadiene chain of an average molar mass of 3200 - 3800, a polydispersity index of about 1.3 and a functionality of about 2.2, in which the number of structural building units of its macromolecule - [CH ₂ -CH = CH-CH ₂ ] -is also about 44 to 57.

- polyisobutadiene (PIB) solid copolymer with 2 mol. isoprene of an average molar mass of 200 000 of the general structural formula:

- [- (CH 2 CH 2 -CH 2 -CH 3 -CH 2 CH 2 CH-CHrkde min.).

In some LBD-containing emulsion mixtures, namely mixtures 1.1, 1.3 and 1.4 of the table, a crosslinking catalyst is used to obtain plastic, well-formable matrices capable of being filled with crystalline additives up to 50% by weight. without losing the coherence of the final mixture. The subject macromolecular additives also increase the lifetime of emulsion explosives containing them (min. 6 months) compared to emulsion explosives without their contents (lifetime 3 6 months).

Example 2 (comparative)

It proceeds according to MS. U. S. Pat. 229745 (1982): a solution of ammonium nitrate (AN) and sodium (SN) 80-90 ^° C warm is introduced into an emulsifying apparatus, to which is added a solution of oleic acid in mineral oil and then an aqueous solution of sodium hydroxide. The mixture is stirred until an emulsion is formed which is sensitized in the homogenizer by the addition of expanded perlite. An emulsion explosive having a composition of 62.9 wt. 13 wt. SN, 12 wt. % water, 2.5% sodium hydroxide, 2.8% wt. % oil, 2.8 wt. % oleic acid and 4 wt. of expanded perlite, which is declared as Emsit. Its specific charge weight is 1.06 g.cm &^lt; ³ &^gt;, its detonation velocity D = 4817 m.s < -1 > and its relative working ability RPS = 69.5%.

The graphical dependence of the relative working ability (RPS) of the emulsion explosives of Example 1 and Example 2 from their brisance, represented by the product of the specific charge mass and the square of the detonation velocity, is constructed, ie p * D ² . It follows from this dependence that the macromolecular components of the oil phase in Example 1 significantly reduce the brisance of the respective emulsion explosives compared to explosives in which these components are not used (including Emsit of Example 2). This effect is significant in the production of mining-safe explosives. The graphical dependence also shows that for both groups of emulsion explosives the increasing solids content of higher molar mass in detonation products corresponds to a decrease in RPS values and an increase in brisance (this also applies to the mineral sensitizer content).

The explosive mixture 1.7 of the table of Example 1, in the form of 32 mm diameter charges, at a detonation rate of 1050 g does not ignite a 9% by volume methane air mixture and 1200 g of coal dust with air concentration of 300 g.m ³ dust. The determined limit charge (diameter 32 mm) of this explosive is 1241 ± 72 g. The gaseous products of its detonation do not contain nitrogen oxides.

Industrial usability

A water-in-oil emulsion matrix suitable for finalizing an emulsion explosive with suppressed fragmentation and retained sliding effect, for example explosives with increased mining safety.

SK 285615 Β6

Table for Example 1

mark Content of individual components in% by weight. Detonainé characteristics mixtures Water AN SN CN SP NaCl wax oil polymer glycol emulsifier MB p focm · ³ ] O (m.s') RPS [%] 1.1 6.86 63.6 13.4 6.7 - - - 3.53 1.57 1.90 (S) 1.96 1,181 3,768.0 71.0 1.2 10,0 65.0 15.5 - - 3.9 0.5 (PIB) - 2,0 (S) 3.0 1,100 4,186.0 67.0 1.3 6.2 58.3 - 24.85 3.3 1.55 (LBD) 0.97 1.94 (S) 2.9 1,067 4,260.0 66.0 1.4 9.3 60.0 20.9 - - 3.4 1.55 (LBD) 1.94 2.9 1,090 4,380.0 63.5 1.5 12.4 53.7 15.5 9.3 3.2 - 0.7 LBD 2,10 (S) 3.1 1,120 4,456.0 61.5 1.6 10,0 57.3 15.0 - 9.0 1.0 2.0 0.7 LBD 2.0 (M) 3.0 1,150 4,463.0 62.0 1.7 10,0 52.8 • 19.0 10.0 3.0 - 0.7 LBD 2,0 (S) 2.5 1,202 4,376.0 61.5 1.8 10,0 58.0 / 15.0 - 8.0 3.3 .. 0.7 LBD 2.0 (M) 3.0 1,150 4,509.6 60.0 1.9 12.4 53J 15.5 - 9.3 3.2 0.7 LBD 2.1 (M) 3.1 1,160 4,567.0 60.5 1.10 9.0 60.0 14.2 7.0 2.0 1.0 1.0 (LBH) 1.8 (M) 4.0 1,130 4,580.0 58.5 1.11 12.0 79.9 - - - 3.1 2.0 (M) 3.0 1.031 4,166.7 76.0 1.1.2 10,0 65.0 - - 15.7 - - 4.3 - 2.0 (M) 3.0 1,055 4,273.5 73.0 1.13 10,0 65.0 - 15.5 - - 4.5 2.0 (M) 3.0 1,085 4,237.3 71.0 1.14 10.0 65.0 15.5 • - - 4.5 - 2.0 (M) 3.0 1,130 4,385.0 70.5

Explanation:

AN - ammonium nitrate SN - sodium nitrate CN - calcium nitrate SP - sodium perchlorate NaCl - sodium chloride MB - glass microballoons LBD - isocyanate-termed polybudadiene P1B - polyisobutylene

LBH - hydroxyterminated polybutadiene

S - sorbitan sesquioleate M - sorbitan monooleate p - density D - detonation rate RPS - relative working ability

Claims (2)

Process for modifying the explosion brisance in the form of a water-in-oil emulsion comprising an oil phase and a discontinuous phase which consists of an aqueous solution of inorganic nitrates and / or perchlorates, or other components of inorganic or organic nature, to which an explosive oil phase is added a modifying agent, characterized in that prepolymers or polymers with building units - [CH ₂ -C (X) = CH-CH ₂ J- in their macromolecule, where X is -H or -CH ₃ which is terminated with hydroxyl or isocyanate groups or polyisobutylene groups, in an amount of 0.5 to 1.8% by weight of the explosive emulsion, the discontinuous phase of which may further comprise a cooling component of the inorganic chloride group. The emulsion-like explosive brisance modification process according to claim 1, wherein the modifying agent is preferably used in an amount of 0.6 to 1.57% by weight of the explosive emulsion.