Classifications

• • C—CHEMISTRY; METALLURGY
  • C06—EXPLOSIVES; MATCHES
  • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
  • C06B25/00—Compositions containing a nitrated organic compound
  • C06B25/34—Compositions containing a nitrated organic compound the compound being a nitrated acyclic, alicyclic or heterocyclic amine
• • C—CHEMISTRY; METALLURGY
  • C06—EXPLOSIVES; MATCHES
  • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
  • C06B21/00—Apparatus or methods for working-up explosives, e.g. forming, cutting, drying
  • C06B21/0033—Shaping the mixture
  • C06B21/005—By a process involving melting at least part of the ingredients
• • C—CHEMISTRY; METALLURGY
  • C06—EXPLOSIVES; MATCHES
  • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
  • C06B25/00—Compositions containing a nitrated organic compound
  • C06B25/04—Compositions containing a nitrated organic compound the nitrated compound being an aromatic

Definitions

• the technical field of the invention is that of fusible / pourable explosive compositions.
• TNT trinitrotoluene
• TNT is most often used in admixture with another more energetic solid explosive, for example hexogen or octogen.
• MURAT attenuated risks
• These composite explosives are used by pouring the explosive mixed with the binder and a polymerization additive. Solidification is obtained by cooking the load.
• the cooking is long (several days). It therefore consumes a lot of energy and therefore cannot be used for large quantities of ammunition.
• ammunition with a composite explosive charge is difficult to demilitarize. Indeed, it is not possible to melt the load to remove it from its envelope.
• the only possible solutions are chemical destruction or detonation, which are costly and harmful to the environment.
• this composition can be used by casting. It also has the advantageous property of being very insensitive to the main vulnerability tests as defined for example by the operating methods described by AFNOR NFT standards 70510 to 70515 or the UN tests 7d) i, 7e), 7g), 7h ), 7j) and 7k).
• TNT melting point of TNT being too low (80.6 ° C), this results in poor resistance of the ammunition to storage under severe thermal stresses.
• TNT can refuse and exude out of the ammunition, all the more since it contains impurities (dinitrotoluene ...) implying the formation of eutectics in combination with TNT (the melting point of eutectics is much lower than 80 ° C).
• the uniformity of the load is no longer ensured, and its detonating characteristics, in particular its low vulnerability, are no longer guaranteed.
• Patents US-A-5,431,756 and DE-A-2,310,217 describe explosive compositions which are liquid at 90 ° C or 100 ° C.
• the first composition being based on TNT and the second based on pentryl and tetryl.
• US-A-3 994 756 proposes an explosive composition which can be poured at 121 ° C. and whose fusible matrix is formed from a mixture of trinitrobenzene and 2,4,6 trinitro-m-xylene.
• Patent FR-A-1,535,427 finally describes an explosive composition based on Trinitromethylaniline.
• the composition proposed by the invention has a sensitivity to heating (slow or rapid), to impact and to detonation by influence which is at least equal to that of known composite explosives. But it can be implemented in a simple and economical industrial way by casting / melting.
• the subject of the invention is a fusible / flowable explosive composition and with reduced vulnerability, and comprising on the one hand a fusible part formed of at least one fusible explosive, at least one phlegmatizer, and at least one phlegmatizer emulsifier in the fusible explosive and on the other hand a solid part comprising at least one solid explosive with reduced vulnerability, composition characterized in that the fusible explosive is a nitrated aromatic whose melting temperature is greater than 100 ° C., the phlegmatizer having a melting temperature substantially equal to that of the fusible explosive and the proportion of phlegmatizer being at least equal to 3% of the total mass of the composition, the assembly having a reaction temperature above 185 ° C.
• the merit of the inventors was to discover that it was possible to design a fusible / pourable explosive using other explosives than TNT.
• These explosives will be chosen with a melting point above 100 ° C., which will ensure the best resistance of the composition to thermal stresses.
• the invention proposes various criteria for choosing explosives which make it possible to obtain a composition with reduced vulnerability which makes it possible to successfully undergo the main standardized tests.
• this family of explosives has a chemical stability analogous to that of TNT, which makes it possible to guarantee a behavior in detonation tests by influence and impact of projectiles which is close to that of TNT.
• the explosives having the highest values low from the point of view of the impact and heating sensitivity coefficients are those belonging to the family of nitro aromatics.
• a suitable phlegmatizer will be combined with such a nitrated aromatic, the melting temperature of which will be substantially equal to that of the explosive (to within plus or minus 2 ° C.), the proportion of phlegmatizer being chosen to be greater than 3%.
• the phlegmatizer will incorporate an emulsifier which will be chosen to ensure the best fused / phlegmatizing explosive interface.
• the phlegmatizer will both promote the dispersion of the powdery constituents and stabilize the emulsion obtained.
• An inert phlegmatizer and emulsifier will be chosen (emulsifiers based on nitrocellulose in particular will be avoided).
• composition will be formulated so that its reaction temperature is above 185 ° C.
• TNMA 2,4,6-trinitro-N-Methylaniline
• Nitrated aromatic explosives have a basic structure consisting of at least one aromatic nucleus comprising at least three NO2 radicals and three other radicals designated for example R, R 'and R ".
• radicals R, R 'and R may be chosen from the radicals: -H, -CH3, -NHCH3, -OH, -NH2 and their combinations.
• the inventors studied the molecular and electronic structures of the various nitro aromatic explosives and chose a number of explosives having both a high melting temperature and good behavior in the aforementioned impact tests by bullet, slow or rapid heating and detonation by influence.
• the explosives selected by the inventors as having a low vulnerability are (in addition to 2,4,6-trinitro-N-Methyl Aniline or TNMA):
• the structure of this body is as follows:
• the fusable part will advantageously constitute between 20% and 40% by mass of the composition.
• the phlegmatizer may be a polyolefin wax and the emulsifier a copolymer of vinyl pyrrolidone.
• the solid explosive with reduced vulnerability may be chosen from the following explosives: oxynitrotriazol (ONTA), triaminotrinitrobenzene (TATB), Nitroguanidine (NGu).
• ONTA oxynitrotriazol
• TATB triaminotrinitrobenzene
• NGu Nitroguanidine
• the composition will advantageously be formulated so that its thermal diffusivity is at least 3.5 10 -7 m 2 / s between 30 and 47 ° C, thus improving the behavior of the composition in the heating tests.
• This thermal diffusivity can be obtained by means of a dispersion of aluminum powder.
• composition comprising:
• the emulsifier is mixed with the phlegmatizer.
• the proportion of emulsifier is chosen to be between 2 and 3% of the total mass of phlegmatizer used.
• 2,4,6-trinitro-N-Methyl Aniline or TNMA is a known explosive, although not used industrially. It is described in particular by patent FR1535427. It is easy to manufacture and has a melting point of 113 ° C to 119 ° C depending on its degree of purity.
• the phlegmatizer selected is a polyethylene wax (a particular type of polyolefin) which is produced under the reference PED121 by the company Hoechst Wachs. Its melting temperature is close to 115 ° C (drop point from 113 to 118 ° C), which corresponds substantially to the melting temperature of TNMA.
• This wax is usually used in the food industry for coating citrus fruits.
• the emulsifier used for this wax is a vinyl pyrrolidone copolymer, which is sold under the name Antaron WP660 by the company International Specialty Products.
• This wax allows the production of a homogeneous and stable emulsion with TNMA and the emulsifier.
• composition was carried out according to the following process:
• the TNMA is melted in a kneader, at a temperature of 125 ° C., under atmospheric pressure.
• the phlegmatizer and the emulsifier are mixed with TNMA while stirring.
• ONTA is then incorporated in the form of a mixture of two different particle sizes and in equal mass proportions.
• a class 2 particle size is used for which the grain size is between 200 and 800 micrometers, and a class 3 particle size for which the average grain diameter is 50 micrometers.
• This combination of particle sizes ensures optimal loading of the composition while retaining good flowability properties.
• the aluminum powder is incorporated with an average particle size equal to 10 micrometers.
• the mixture is poured into an ammunition envelope maintained at the temperature of 120 ° C.
• the assembly is then gradually cooled in order to avoid porosity and recession.
• the cooling time is around fifteen hours.
• the ammunition envelope containing the composition according to the invention was subjected to a certain number of the tests described by AFNOR standards 70513 and 70515 and the UN tests 7d) i, 7f) and 7j).
• the ammunition casings tested are models conforming to those defined by the GEMO 3L1 operating mode (3 liter casing containing 5 kg of explosive, steel wall 10mm thick, diameter of the explosive block approximately 123mm, length of the explosive block approx. 239 mm).
• a shot is made with a 12.7 mm caliber bullet.
• the impact on the model envelope is located in the axis of this one and halfway up.
• the test is conducted at room temperature (20 ° C) and for an impact speed of 850m / s.
• the criterion for acceptance is the absence of detonation or violent reaction.
• a model as defined above is placed above a fuel tank, its lower generator being 250 mm from the latter.
• the fuel used is kerosene.
• the average flame temperature being greater than or equal to 800 ° C.
• the criterion for acceptance is the absence of detonation or violent reaction.
• the model is placed in the center of an electric oven ensuring a temperature rise of 3.3 ° C per hour.
• the acceptance criterion is the absence of a violent reaction with projection of splinters.
• composition according to the invention has a level of non-vulnerability as good as that of the known composition.
• the detonic characteristics of the composition according to the invention have a performance level at least equivalent to that of the known composition.
• a detonation speed of 6,830 m / s was thus measured with the composition according to the invention, the known composition based on TNT having a speed of 6,770 m / s.
• composition according to the invention has a very low vulnerability while retaining advantageous detonating properties.
• the phlegmatizer used is a consumer product produced in large quantities and for which supply problems do not arise.
• the main function of aluminum powder is to improve the blowing effect of the composition. It also makes it possible to improve the thermal conductivity of the composition. An increase in the mass of aluminum therefore also makes it possible to increase the resistance of the composition to heating (slow or rapid).
• composition another solid explosive than ONTA, for example octogen.
• a proportion of explosive that is not very vulnerable will preferably be left, which will be greater than 20% by mass in order to maintain attractive qualities of low vulnerability.
• CS specific sensitivity criterion
• Explosive compositions CS criteria TNMA 30% / ONTA 40% / Al 20% / wax 10% 73 TNT 30% / ONTA 40% / Al 20% / wax 10% 75 TNMA 36% / ONTA 40% / Al 20% / wax 4% 92 TNMA 37% / ONTA 40% / Al 20% / wax 3% 96 TNMA 38% / ONTA 40% / Al 20% / wax 2% 100 Explosive materials CS criterion TATB 125 HAVE A 133 TNMA 165 TNT 181 Hexogenous 233
• the vulnerability tests conducted were able to show that a composition whose CS was greater than or equal to 100 could not satisfy all the vulnerability tests.
• One of the essential criteria for defining a composition capable of satisfying thermal and mechanical aggression tests is therefore the choice of a percentage of phlegmatizer (wax) greater than or equal to 3%.
• compositions may also be produced, in which the phlegmatizer is each time the wax described above in which the emulsifier is incorporated:
• Hexogen could also be used as a complementary energy explosive.
• compositions can be produced:

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Medicinal Preparation (AREA)
• Manufacturing Of Micro-Capsules (AREA)
• Heat Sensitive Colour Forming Recording (AREA)
• Fire-Extinguishing Compositions (AREA)

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Citations (8)

• 1996
  • 1996-06-19 FR FR9607643A patent/FR2750131B1/fr not_active Expired - Fee Related
• 1997
  • 1997-06-19 EP EP97401425A patent/EP0814069B1/de not_active Expired - Lifetime
  • 1997-06-19 AT AT97401425T patent/ATE215058T1/de not_active IP Right Cessation
  • 1997-06-19 DE DE69711268T patent/DE69711268T2/de not_active Expired - Lifetime
  • 1997-06-20 NO NO972873A patent/NO308595B1/no not_active IP Right Cessation

Patent Citations (8)

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