Classifications

• • 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
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L1/00—Compositions of cellulose, modified cellulose or cellulose derivatives
  • C08L1/08—Cellulose derivatives
  • C08L1/16—Esters of inorganic acids
  • C08L1/18—Cellulose nitrate, i.e. nitrocellulose
• • 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
  • C06B21/0066—Shaping the mixture by granulation, e.g. flaking
• • 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
  • C06B25/18—Compositions containing a nitrated organic compound the compound being nitrocellulose present as 10% or more by weight of the total composition

Definitions

• the invention relates to a method for producing shaped nitrocellulose as well as explosive substances and propellants according to the preamble of claim 1 , to a method for producing a varnish made from a substantially water-free explosive substance, or a varnish made from an explosive substance having a defined water content, according to the preamble of claim 8 , to use of a varnish made from a water-free explosive substance according to the preamble of claim 10 , and to a varnish made from nitrocellulose according to the preamble of claim 11 .
• explosive substances is understood to mean explosive and/or potentially explosive, in particular solid, liquid, and gelatinous, substances and substance mixtures that are used as explosive agents, propellants, detonating agents, or pyrotechnic devices, or for the manufacture of same.
• Explosive substances are used for numerous applications, particularly in the munitions sector. For efficient and effective use, as a rule it is necessary for the explosive substances to be present in a specific geometry, for example in a spherical shape. This allows explosive substances, in the form of propellant charges, for example, to be loaded into shell casings. To ensure homogeneous and uniform combustion of the explosive substances, it is necessary that the explosive substances have a defined structure and defined geometry, the latter being achievable, for example, when the explosive substances are present in uniform sizes, preferably as spherical or spheroidal particles. Nitrocellulose as well as the previously described explosive substances may also represent a raw material for varnish production. Spherical nitrocellulose as raw material for varnish production offers the advantages that in this form it is stabilized, even without moistening agents, is easy to handle, and allows for the incorporation of additives.
• spheroidal propellant charge powder One application in the area of explosive substances is the production of spheroidal propellant charge powder.
• shaping was accomplished by dissolving water-moistened nitrocellulose in ethyl acetate and then distributing this organic phase in an aqueous phase by intensive stirring.
• basically particles with very irregular sizes are formed.
• the particles are very susceptible to enlargement by coalescence, since the varnish for this type of particle formation must have only a very low viscosity, which in turn facilitates coalescence.
• the solvent is evaporated with stirring, and the nitrocellulose remains in the aqueous phase in the form of rounded particles.
• Another method for producing spherical nitrocellulose particles uses an underwater granulator for formation of the particles.
• the organic phase is pressed through a perforated disk into the aqueous phase, and the strands exiting the orifices in the perforated disk are broken up into particles by a rotating blade on the exit side. It is necessary to screen the formed particles in this method as well.
• Further disadvantages of this method are that the organic phase for use in the underwater granulator must have such a high consistency that the cylindrical particles which primarily result in the normal stirring process are no longer round. They must therefore be conveyed through long pipes having small cross sections, thereby imparting roundness by the intensive contact with the pipe walls.
• High throughputs in the device require high rotational speeds for the blade.
• the increasing speed of the rotating blade also increases the hydraulic shear forces, which very quickly result in diminished quality due to further uncontrolled size reduction of the particles.
• the rotational speed of the cutting blade which is thereby greatly limited from above, significantly restricts the efficiency of the device.
• the particles are hardened by stripping the solvent, as in the previously described method.
• the particles produced by both methods contain undefined quantities of dispersed water which create an undefined porosity in the finished particle.
• this is a key quality feature for the product, since the porosity greatly influences the combustion of the product.
• minimal to high porosities may be desirable, which however must have a precisely defined consistency.
• the water content has been adjusted by dewatering prior to hardening of the particles. This was generally achieved by making use of the osmotic effect created by the addition of sodium sulfate to the aqueous dispersion. The extent of dewatering was controlled by the salt concentration, the length of the reaction, and the temperature. This dewatering process is very difficult to control and produces unsatisfactory results.
• the object of the invention is to provide a method and a substance for producing shaped explosive substances by which the aforementioned disadvantages, in particular porosity, water and salt content, non-uniform particle size, and environmental impacts, are avoided.
• the method for producing shaped explosive substances, in particular propellant charge powder such as spheroidal propellant charge powder, for example, from an explosive substance stabilized in particular with water comprises the following steps according to the invention:
• stabilizing substance is understood to mean for example water, or also a salt or other organic or inorganic non-reactive or inert substances such as alcohol or softeners, for example.
• the stabilizing substance in particular water
• the water is removed by azeotropic distillation.
• the water may be removed from the explosive substance efficiently, effectively, and safely.
• the solvent is returned to the explosive substance.
• a varnish made from explosive substance having a predefined viscosity, the viscosity being adjustable by the type and/or quantity of solvent as well as by the use of auxiliary agents.
• Surface-active substances, wetting agents, or separating agents, for example, may be used as auxiliary agents.
• the stabilizing substance is a solid, salt, or other substance difficult to distill
• the invention provides that this substance is extracted with suitable solvents.
• a solid phase extraction or precipitation for example, is also possible if this is compatible with the type of explosive substance, in particular the density and solubility thereof. Extraction by sublimation is also possible, provided that this can be performed safely.
• the shaping of nitrocellulose and/or explosive substance particles is carried out or initiated by jet cutting, in which a jet, preferably a full jet, of an explosive substance-solvent mixture or an explosive substance-solvent solution, in particular a varnish made from an explosive substance, is subdivided by use of a separating device into jet segments having a defined and/or adjustable length which fall into a fluid, preferably a fluid in motion, in which the explosive substance-solvent mixture, in particular varnish made from an explosive substance, is poorly soluble and/or essentially insoluble.
• This method is extremely well suited for producing spheroidal particles of approximately equal particle size for processing explosive substance-solvent mixtures.
• the organic phase of the fluid to be processed and from which the particles are to be produced is pressed in the form of a full jet at high velocity from a nozzle.
• a rotating cutting tool composed of short wires which are preferably held in a mounting and point outward, which breaks up the fluid jet into cylindrical segments. As these segments continue to fall, as a result of the surface tension of the fluid they form spherical particles which are collected in a solvent, in particular water.
• the size of the particles produced is adjustable as a function of the nozzle diameter, the volumetric flow through the nozzle, the number of cutting wires, and the rotational speed of the cutting tool, and according to the invention lies in the range of 0.1 mm to 10 mm, preferably in the range of 0.2 mm to 2 mm, and particularly preferably in the range of 0.5 mm to 1.5 mm.
• the jet cutting ensures that it is possible to produce only particles which have a desired size and are adjustable using the aforementioned parameters, and that the explosive substance particles produced essentially contain only explosive substance and solvent, but none, or a precisely defined quantity, of a stabilizing substance.
• the advantages of the jet cutting method are described below.
• the inclination of the cutting plane with respect to the jet axis enables substantially cylindrical particles, which are already approximately spherical, to be cut from the moving jet.
• the cutting device operates in air, thereby permitting very high cutting frequencies and therefore high throughputs.
• the cutting tool does not make contact with the exit orifice.
• losses due to a non-homogeneous particle distribution may be reduced to less than 3%, in particular to less than 2%, of the explosive substance-solvent mixture used.
• An explosive substance which is sufficiently viscous and is capable of being handled safely without solvent may be used directly in the jet cutting method.
• a further significant advantage of the invention is that explosive substance particles having a defined porosity can be produced, the rate of porosity being adjustable by, for example, introduction of suitable substances, in particular water, into the varnish made from an explosive substance.
• suitable substances in particular water
• substances are preferably used which can be diffused or dissolved out of the explosive substance particle, thereby leaving a cavity in the explosive substance particle.
• salts or similarly non-reactive substances which remain in solid form in the explosive substance particle.
• the speed and temperature of combustion, and thus the speed of detonation of the explosive substance may be advantageously influenced.
• multilayer explosive substance particles whereby in the jet cutting process various varnishes made from an explosive substance may be introduced through one central nozzle and one or more annular nozzles. It is thus possible to produce, for example, an explosive substance having an inwardly increasing speed of combustion, whereby for this purpose an outer layer contains, for example, an appropriate quantity of a stabilizing substance or a slow-combusting explosive substance.
• water-containing nitrocellulose is used as stabilizing [sic; stabilized] 1 explosive substance and ethyl acetate is used as solvent.
• This explosive substance-solvent system is extremely well suited for producing spherical, water- and salt-free nitrocellulose particles which in particular are optimally suited for producing spheroidal propellant charge powder.
• the object of the invention is further achieved by a method for producing a varnish made from a substantially water-free explosive substance, or a varnish made from an explosive substance having a defined water content, in particular nitrocellulose varnish, from an explosive substance stabilized in particular with water, whereby the method comprises the following steps:
• the significant advantage of this aspect of the invention is based on the fact that a varnish made from a substantially water-free explosive substance is suitable for producing water-free and also salt-free explosive substance particles, since according to the method, before being used for the varnish made from an explosive substance these particles have been removed from a matrix from which the particles were produced.
• the solvent is returned to the explosive substance before and/or after the distillation.
• auxiliary agents such as in particular surface-active substances, wetting agents, separating agents, and agents for adjusting the viscosity, may be used.
• wetting and/or separating agents By the use of wetting and/or separating agents it is possible, for example, to optimally match the varnish made from an explosive substance with the materials with which the varnish is combined in the production process, so that, for example, contamination resulting from adhesion of the explosive substance to the equipment used is minimized or completely eliminated.
• contamination resulting from adhesion of the explosive substance to the equipment used is minimized or completely eliminated.
• such measures contribute to handling and operational safety in the production of explosive substances.
• the object is further achieved by use of a varnish made from a substantially water-free explosive substance, in particular a nitrocellulose varnish, for producing shaped, in particular spherical or spheroidal, explosive substances.
• the object of the invention is further achieved by a nitrocellulose varnish composed of at least nitrocellulose and a solvent, the nitrocellulose varnish being substantially water-free.
• the nitrocellulose varnish has a viscosity which allows, in particular by use of the jet cutting method, particles having a predefinable particle size in the range of 0.1 mm to 10 mm, preferably in the range of 0.2 mm to 2 mm, and particularly preferably in the range of 0.5 mm to 1.0 mm, to be shaped.
• the nitrocellulose varnish preferably contains auxiliary agents, in particular surface-active substances, wetting agents or separating agents, and agents for adjusting the viscosity.
• the nitrocellulose varnish is substantially salt-free.
• nitrocellulose cellulose nitrate with a N content of approximately 12.5%
• nitrocellulose cellulose nitrate with a N content of approximately 12.5%
• the mixture was azeotropically distilled, the azeotrope removed by distillation being dewatered and the ethyl acetate being continuously returned to the distillation.
• this solution was supplied to a jet cutting method, using separating wires with a thickness of 0.05 mm.
• the resulting particles were collected in water; the water, which may contain a separating agent, was kept in motion by a stirrer.
• the water-particle mixture was concentrated under simultaneous application of a vacuum until the particles were essentially solvent-free in the water. Due to the hydrophobicity of the particles, there is no risk of diffusion of water into the particles. After the distillative concentration the resulting particles were filtered from the particle-water mixture. The particle size obtained was 0.8 mm diameter. The yield relative to the nitrocellulose used was 98.5%.
• nitrocellulose cellulose nitrate with a N content of approximately 13.2%
• nitrocellulose cellulose nitrate with a N content of approximately 13.2%
• the mixture was azeotropically distilled, the azeotrope removed by distillation being dewatered and the ethyl acetate being continuously returned to the distillation.
• 100 g metriol trinitrate dissolved in 200 g ethyl acetate was added to the mixture.
• the resulting varnish made from explosive substance was then supplied to the jet cutting process and further processed, as previously described.
• nitrocellulose cellulose nitrate with a N content of approximately 12.2%
• nitrocellulose cellulose nitrate with a N content of approximately 12.2%
• the mixture was azeotropically distilled, the azeotrope removed by distillation being dewatered and the ethyl acetate being continuously returned to the distillation.
• 20 g dibutyl phthalate dissolved in 200 g ethyl acetate was added to the mixture.
• the resulting nitrocellulose varnish was then supplied to the jet cutting process and further processed, as previously described. It should be noted here that all the sections described above, singly or in any combination, are claimed as essential to the invention. Those skilled in the art are familiar with modifications thereto.

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• Chemical & Material Sciences (AREA)
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• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
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• Processes Of Treating Macromolecular Substances (AREA)
• Paints Or Removers (AREA)
• Cosmetics (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)

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• 2001
  • 2001-10-24 DE DE10152396A patent/DE10152396A1/de not_active Withdrawn
• 2002
  • 2002-10-23 AU AU2002346869A patent/AU2002346869A1/en not_active Abandoned
  • 2002-10-23 WO PCT/EP2002/011850 patent/WO2003035581A2/de not_active Application Discontinuation
  • 2002-10-23 US US10/493,367 patent/US20050000610A1/en not_active Abandoned
  • 2002-10-23 CN CNA028208064A patent/CN1703385A/zh active Pending
  • 2002-10-23 KR KR10-2004-7005814A patent/KR20040060942A/ko not_active Application Discontinuation
  • 2002-10-23 EP EP02782986A patent/EP1438274A2/de not_active Withdrawn
• 2004
  • 2004-04-05 ZA ZA2004/02643A patent/ZA200402643B/en unknown

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