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
  • C06B45/00—Compositions or products which are defined by structure or arrangement of component of product
  • C06B45/04—Compositions or products which are defined by structure or arrangement of component of product comprising solid particles dispersed in solid solution or matrix not used for explosives where the matrix consists essentially of nitrated carbohydrates or a low molecular organic explosive
  • C06B45/06—Compositions or products which are defined by structure or arrangement of component of product comprising solid particles dispersed in solid solution or matrix not used for explosives where the matrix consists essentially of nitrated carbohydrates or a low molecular organic explosive the solid solution or matrix containing an organic component
  • C06B45/10—Compositions or products which are defined by structure or arrangement of component of product comprising solid particles dispersed in solid solution or matrix not used for explosives where the matrix consists essentially of nitrated carbohydrates or a low molecular organic explosive the solid solution or matrix containing an organic component the organic component containing a resin
  • C06B45/105—The resin being a polymer bearing energetic groups or containing a soluble organic explosive

Definitions

• the present invention relates to the use of beta-octogenes with a polymodal grain size distribution with an average grain diameter of less than 50 ⁇ m in blowing agents.
• octogen is known to mean 1.3.5.7-tetranitro-1.3.5.7-tetrazacylooctane or cyclotetramethylene tetranitramine.
• This compound is also known as HMX (High Melting Explosive of His Majesty's Explosive).
• HMX High Melting Explosive of His Majesty's Explosive.
• Four crystal modifications of this compound are known, namely the orthorhombic alpha form, the monoclinic beta form, the monoclinic gamma form and the hexagonally crystallizing delta form.
• the use of the beta form is described in the context of the present invention.
• This form is the common modification, the quality control of which is described in Military Specification MIL-H-45444 B (PA), Amendment 1.15 July 1975. A distinction is made between purity levels A and B.
• beta-octogen has been used in the prior art as the sole explosive in passivated form, as a booster charge, in mixtures with TNT (octols) and others, and as an explosive in rocket propellants or in gun propellants.
• TNT octols
• the known areas of application thus relate to both detonative and explosive implementations or deflagrations.
• Detonative is known to mean reactions that take place significantly below the speed of sound in the material. The reactions propagate through the heat of reaction released. The reaction products flow opposite to the direction of propagation. In contrast, the detonative implementation of an explosive is known to be coupled with a shock wave when it reacts.
• the combustion of a propellant powder is a deflagration process.
• the determination of the burning rate can be used as a suitable measurement variable.
• the linear burning rate of a propellant is the rate at which the chemical reaction proceeds from the point of ignition. It depends on the composition, pressure, temperature, the physical state of the blowing agent and its shape.
• the physical state of the blowing agent in this sense includes in particular the porosity, compression and the grain size and grain size distribution of the components.
• Such dependencies are described in the literature when beta-octogen is used as an energy source for blowing agents.
• the Technical Memorandum 33-801 with the title "Nitramine Propellant Research” of the Jet Propulsion Laboratory, Pasadena CA, October 15, 1976, the internal ballistics of fine-grained beta-octogen is examined. over the dependence of the linear burning speed on the muzzle pressure is reported (in German translation): "The use of fine grain size should be an effective step in postponing the occurrence of breakpoints," noticeable by a sudden sharp increase in muzzle pressures, "with nitramine propellants.
• the breaking point of the 20 ⁇ m particles occurs at 280 bar (4000 psi), that of the 10 ⁇ m particles at 420 bar (6000 psi) and that of the 5 ⁇ m particles at 1380 bar (20,000 psi).
• the effects of the 10 ⁇ m and 20 ⁇ m particles are greater than their low concentration (a total of 17%) could be expected, because of their deep penetration during combustion on the surface structure of the propellant.
• a real blowing agent would show an extended transition instead of a step-like transition. From this it follows that, if appropriate procedures are followed, coarse particles in the batches have to be sieved out in order to obtain fine octogen. This is of greater importance with blowing agents containing inert binders than with blowing agents containing active binders because of the moderate combustion of the blowing agents by active binders.
• the slope of the pressure exponent can be determined from the curves measured in this way.
• an excessively steep pressure rise is undesirable. From studies by the German-French Research Institute, St. Louis, it is known that the following applies to nitramine powders based on hexogen: the finer the grain, the lower the pressure exponent of the burning rate and the burning rate itself.
• the grain size of the hexogen is from 4 to 15 ⁇ m a pressure exponent ⁇ 1 is reached.
• the maximum pressures of more than 6000 bar are too high.
• DE 36 14 173 C1 discloses a granulated beta-octogen with a grain size of less than 50 ⁇ m, which is coated with plastics.
• the object of the present invention was to find an octogen with a suitable grain shape, grain size and grain size distribution to prevent the jumps in the curves of the linear burning speed against the pressure.
• the pressure exponent of the burning rate should be ⁇ 1.
• the object of the present invention was to reduce the pressure rise gradient and the maximum pressure in the cartridge chamber compared to the prior art.
• the above-mentioned object is achieved by the use of beta-octogenes with a polymodal grain size distribution with an average grain diameter of less than 50 ⁇ m in blowing agents made from explosives, inert and active binders.
• Polymodal grain size distribution in the sense of the present invention means a grain size spectrum, as can be represented in particular by a Gaussian distribution curve.
• the production of particularly fine-grained beta-octogen is known from DE 36 17 408 C1. After that, a solution of beta-octogen in a gamma-lactone in the temperature range between 5 and 15 ° C with Toluene treated, the desired fine and very fine beta-octogen crystals precipitate in high purity.
• the very fine beta-octogen can be slurried in water after being separated from the toluene and the solution, suspension or emulsion of a polymer can be added at temperatures between 30 and 60 ° C. with stirring. A coating with the polymer takes place.
• beta-octogen grain Another method for producing the very fine beta-octogen grain consists in comminuting a commercially available product as classified according to MIL-H-45444 B.
• the grain sizes range from about 45 ⁇ m to a few hundred ⁇ m.
• the crushing of the crystals by grinding encounters great difficulties, however, since beta-octogen is extremely sensitive to friction and impact. This process can therefore only be carried out under special safety precautions in appropriate devices.
• Another method for producing a particularly fine-grained beta-octogen consists in the separation of the desired grain fractions.
• the starting product can come from normal production or from the comminution reaction described above.
• the separation methods are known per se.
• the advantage of a granulation according to the present invention is the use of hydrocyclones. It goes without saying that a particularly fine grain size makes up only a fraction of the mass used, which makes the process itself more expensive.
• the particular advantage of the direct production of fine grain size is that the crystals from the crystallization are intact compared to those from the crushing process.
• a preferred active binder for the purposes of the present invention is polynitrophenylene.
• nitrocellulose can also be used as an active binder.
• beta-octogen according to the present invention is to use it in blowing agents which contain hexogen, guanidine nitrate, hexanitrodiphenylamine, dipicrylsulfone, hexanitrostilbene and / or tetranitrodibenzo-1,3a-4,6a-tetraazapentalene as further explosives.
• Propellants according to the invention contain not only active but also inactive binders. This includes in particular those based on plastics. Since, in addition to reducing the detonation sensitivity, the use of binders also entails solidification of the crystal powder, good adhesive properties and good dimensional stability in the temperature range from -40 ° C. to +70 ° C. are desirable. In addition, the binders should be halogen-free and should give little solid combustion products.
• Preferred binders are those based on polyurethanes, polymethylacrylates, polyvinyl acetates, silicone and polyvinyl alcohols, in particular partially or fully acetalized polyvinyl alcohols with C1 to C5 aldehydes, which are commercially available per se.
• the polyvinyl butyral resin, which is commercially available, is of particular importance here.
• the Art and the amount of binder depends on the desired application, in particular for controlling the internal ballistics according to the shape.
• the amount of active and inert binder is in each case independently of one another 5 to 15% by weight, based on the blowing agent.
• blowing agents obtainable with the aid of the invention can also contain plasticizers, lubricants and / or stabilizers known per se in the prior art.
• blowing agents can be used in loose or compressed form. According to the invention, blowing agents are preferably used in compressed form.
• beta-octogen in explosives, inert and active binders is not critical.
• beta-octogen can be used in the above-mentioned blowing agents without further aftertreatment.
• a particular embodiment of the present invention consists, however, in coating the crystals of beta-octogen with thermoplastic polymers before use in the blowing agents mentioned.
• beta-octogen with an average grain size of less than 50 ⁇ m is to be used according to the present invention, it is particularly preferred that at least 95% of the beta-octogen have an average grain size of less than 100 ⁇ m.
• the invention is illustrated by the following examples and comparative examples.
• the propellant was processed into cartridges. Neither the heat of explosion of the propellant nor its mass nor the ignition system of the cartridge were changed compared to the comparative example. The bombardment results were determined with a gas pressure meter. The propellant powder mass was 1.61 g in each case. Table I below shows the data obtained. Table I Example No. See.
• Table II below shows the grain size spectrum of the beta-octogen with an average grain size of 23 ⁇ m.
• Table II Particle size distribution beta-octogen, average particle size 23 ⁇ m. ⁇ 10 ⁇ m 6.5% by weight 10 - 20 ⁇ m 46.5% by weight 20 - 30 ⁇ m 27.0% by weight 30 - 40 ⁇ m 10.0% by weight 40 - 50 ⁇ m 4.0% by weight 50 - 60 ⁇ m 2.5% by weight 60 - 80 ⁇ m 3.5% by weight 100% by weight
• the composition of the blowing agents from Examples 5 and 6 was identical except for the difference in the octogen grain sizes of 23 and 9 ⁇ m.
• the latter has a grain size distribution similar to that of the octogen with an average grain size of 23 ⁇ m.
• the manufacture of the cartridges, their propellant masses, dimensions and the ignition systems were identical.
• the results are averages from 10 rounds.
• the bombardment result makes it clear that, despite the same energy content, the pressure rise gradient when using an average beta-octogen grain size of 9 ⁇ m is clearly below that for 23 ⁇ m.
• a blowing agent with the same proportion of energy source but here consisting of beta-octogen with an average grain size of 6 microns, inert and active binders were mixed in the same composition and cartridges were produced from this mixture using the same method with an identical ignition system .
• Table V The results of 30 rounds in the same gas pressure meter as used for Examples 1 to 4 and the comparative example, with a propellant powder mass of 1.64 g, are shown in the following Table V, which contains the averaged results: Table V Max. Pressure (bar) 2570 Standard dev. (bar) 556 Shot time (milli-s) 7.2 Bullet speed (m / s) 766

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• Agricultural Chemicals And Associated Chemicals (AREA)
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• 1991
  • 1991-08-15 DE DE4126981A patent/DE4126981C1/de not_active Expired - Fee Related
• 1992
  • 1992-08-17 DE DE59204051T patent/DE59204051D1/de not_active Expired - Lifetime
  • 1992-08-17 EP EP92113959A patent/EP0528392B1/de not_active Expired - Lifetime
• 2000
  • 2000-12-12 US US09/733,963 patent/US20010023727A1/en not_active Abandoned

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