Classifications

• • C—CHEMISTRY; METALLURGY
  • C06—EXPLOSIVES; MATCHES
  • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
  • C06B23/00—Compositions characterised by non-explosive or non-thermic constituents
  • C06B23/04—Compositions characterised by non-explosive or non-thermic constituents for cooling the explosion gases including antifouling and flash suppressing agents
• • 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
• • 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
  • C06B31/00—Compositions containing an inorganic nitrogen-oxygen salt
  • C06B31/02—Compositions containing an inorganic nitrogen-oxygen salt the salt being an alkali metal or an alkaline earth metal nitrate
  • C06B31/12—Compositions containing an inorganic nitrogen-oxygen salt the salt being an alkali metal or an alkaline earth metal nitrate with a nitrated organic compound
  • C06B31/22—Compositions containing an inorganic nitrogen-oxygen salt the salt being an alkali metal or an alkaline earth metal nitrate with a nitrated organic compound the compound being nitrocellulose
  • C06B31/24—Compositions containing an inorganic nitrogen-oxygen salt the salt being an alkali metal or an alkaline earth metal nitrate with a nitrated organic compound the compound being nitrocellulose with other explosive or thermic component
• • 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
  • C06B45/12—Compositions or products which are defined by structure or arrangement of component of product having contiguous layers or zones

Definitions

• the invention relates to a powder as drive powder or igniter powder for accelerating projectiles for mortar systems, which is based on nitrocellulose and contains a crystalline energy carrier based on nitramine in 1-30% by weight and an inorganic flash hider, the powder being in the form of grains , and the grains optionally have an inert plasticizing additive on their surface.
• the invention also relates to a method for producing such a powder.
• the WO 2011/153655 A2 discloses a drive system for projectiles which does not contain nitroglycerine and is suitable for small-caliber and mortar projectiles.
• the composition of the grain consists of nitrocellulose, a nitramine-based energy carrier and one or more inert plasticizers, which preferably have an increased concentration in an area near the surface.
• the EP 1 857 429 A1 (Nitrochemie Wimmis AG) describes a drive for accelerating projectiles, which is based on nitrocellulose.
• the drive comprises nitrocellulose as a base, a crystalline energy carrier based on nitramine in an amount of 1 - 25% by weight and at least two inert plasticizing additives, one of the additives being homogeneously distributed in the matrix of the drive and the second additive in one near the surface has an increased concentration.
• This composition results in a drive with a high degree of energy conversion, the drive preferably being in the form of grains.
• the object of the invention is to create a powder belonging to the technical field mentioned above as a drive powder or ignition powder for accelerating projectiles for mortar systems, which has excellent chemical and ballistic stability and can be implemented with a high output.
• a powder is provided as a drive powder or ignition powder for accelerating projectiles for mortar systems, which powder is based on nitrocellulose.
• the powder contains a crystalline energy carrier based on nitramine in 1-30% by weight and an inorganic flash hider in 0.1-10% by weight.
• the powder is in the form of grains.
• the grains have an inert plasticizing additive on their surface.
• the additive is camphor and is present in a range of 0.01-1% by weight.
• the increase in the muzzle velocity with increasing temperature is also relatively small, so that the drive is characterized overall by largely neutral temperature characteristics
• the powder according to the invention has a high degree of energy conversion with a flat pressure profile, which leads to a high internal ballistic performance.
• Mortar systems are generally understood to mean systems that have a relatively short barrel and are fired at relatively steep angles. There are mortars from caliber 37 mm (light mortars) up to 240 mm (super-heavy mortars). The most important are the heavy mortars in calibers 60 - 120 mm. The invention particularly focuses on the mortars and the corresponding drives for systems of calibers 60 mm, 81 mm and 120 mm.
• the powders according to the invention can also be used as igniter powders for mortar applications.
• a kindling powder is housed in the shaft of a mortar shell and is needed to amplify the impulse of the pyrotechnic initial ignition and to transfer it to the drive powder in the surrounding increments (horse shoes).
• the composition of a lighting powder is identical to the composition of a drive powder. However, they can differ in grain size and grain geometry.
• Both the drive powder and the ignition powder are extrudable bulk powders that can be produced in a solvent process and contain nitrocellulose as the main component.
• nitrocellulose has been the most important raw material for the production of single-, double- and tri-base propellant powders. It is obtained through the nitration of cellulose (cotton linters, cellulose), is available in large quantities at low cost and is available in a wide range of different chemical-physical properties offered.
• Nitrocellulose varies e.g. B. with regard to the nitrogen content, molecular weight or viscosity and, due to these differences, can be processed into the various homogeneous propellant powder types. The energy content of nitrocellulose is adjusted via the nitrogen content. In single-base formulations, nitrocellulose is the sole energy carrier, which means that the energy density of nitrocellulose is relatively high compared to other synthetic binder polymers.
• the present powders are based on nitrocellulose. This preferably has an average nitrogen content of 12.6-13.25%.
• the other key components contained in the grain matrix are a crystalline energy carrier and an inorganic flash hider.
• the crystalline energy carrier increases the energy content of the powder and is used in a concentration in the range from 1 to 30% by weight. With these proportions in a base made of nitrocellulose, it is achieved that the mean distances between the individual crystals of the crystalline energy carrier are sufficiently large so that the individual crystals do not touch each other for the most part. This ensures that when external mechanical stimuli are applied, the shock pulse cannot be passed on from an explosive crystal to the neighboring crystals. In this way, a primarily acting shock pulse is not multiplied and transmitted over the entire amount of powder. On the other hand, with higher weight proportions of crystalline energy carriers, the individual crystals are statistically too close to one another, which greatly increases the vulnerability of the powder.
• the inorganic flash hider is used in a concentration in the range of 0.1-10% by weight.
• an inorganic flash hider By adding an inorganic flash hider, the conversion of unburned gases such as hydrogen or carbon monoxide in the area of the gun muzzle is suppressed so that they do not ignite or only ignite to a very lesser extent.
• the muzzle flash is reduced, which on the one hand reduces the dazzling effect of the fire for the shooter and also makes it more difficult to locate the shooter.
• the crystalline nitramine-based energy carrier is preferably at least one compound from the group comprising hexogen (RDX) and octogen (HMX).
• RDX hexogen
• HMX octogen
• RDX is preferably used as a crystalline energy carrier. Compared to HMX, it is cheaper and safer to manufacture. HMX is more expensive than RDX, but offers no particular advantages. Other nitramine compounds (such as NIGU etc.) have relatively little performance compared to RDX. For stabilization, active ingredients known per se, such as. B. Akardit II can be used
• the crystalline nitramine compound particularly preferably has a defined mean grain size. So z. B. RDX is preferably used with an average grain size of 4-8 micrometers, in particular 6 micrometers.
• the homogeneous particle size of the crystalline energy carrier enables powders to be produced that have relatively constant chemical and ballistic properties.
• nitrate esters are less chemically stable.
• nitramine compounds Hexanitroisowurtzitan (CL-20, CAS # 14913-74-7 ), Nitroguanidine (NIGU, NQ, CAS # 70-25-7 , N-methylnitramine (tetryl, N-methyl-N, 2,4,6-tetranitrobenzolamine, CAS # 479-45-8 ) as well as nitrotriazolone (NTO, CAS # 932-64-9 ) and triaminotrinitrobenzene (TATB, CAS # 3058-38-6 ). All of these energetic connections can be used individually or in combination with one another.
• the proportion of the crystalline energy carrier is particularly preferably 5-25% by weight.
• powders are favored which contain crystalline energy carriers in proportions of 10-20% by weight.
• proportions by weight below 25% by weight, in particular up to 20% by weight, the individual crystals of the energy carrier are spaced from one another in such a way that the The powder's vulnerability is at a very low level.
• the use of an inert plasticizing additive can somewhat reduce the vulnerability of the powder with a relatively high proportion by weight of the crystalline nitramine compound. It is thereby easily possible to use high proportions of the crystalline nitramine compound.
• RDX In addition to its property as a crystalline energy carrier, RDX also has certain stabilizing properties that come into play from approx. 1% by weight and increase only insignificantly with increasing proportion.
• the inorganic flash hider is preferably at least one compound from the group of alkali salts such as. B. Potassium Nitrate and Potassium Sulphate. In addition to reducing the muzzle flash, these compounds can also accelerate the burn and thereby reduce the formation of residues, which further increases the degree of energy conversion.
• the inorganic flash hider is present in a proportion of 0.1-5% by weight.
• the surface of the powder grain is preferably treated with graphite and ethanol.
• the extruded powder grains are preferably subjected to a surface treatment with ethanol and graphite.
• the surface is treated with camphor as an inert plasticizing additive.
• the inert plasticizing additive penetrates into the near-surface zones of the powder grain and remains there, ie it is localized and does not distribute itself in the grain matrix.
• the inert plasticizing additive has a penetration depth of a few 100 micrometers, e.g. B. a maximum of 400 micrometers, preferably 100-300 Micrometer. This means that at least 95% by weight of the inert plasticizing additive is contained up to this depth.
• the applied graphite preferably remains on the surface of the powder grain.
• the surface treatment i.e. the application of ethanol, graphite and the inert plasticizing additive to the surface of the extruded powder grain, has a positive influence on the properties of the powder grain.
• a temperature-neutral behavior and the bulk density i.e. how much powder can be accommodated in a given container volume
• the pressure level i.e. the ratio of peak gas pressure to muzzle velocity
• the grain matrix does not contain more inert compounds than necessary, and can therefore have the greatest possible amount of energetic compounds.
• a surface treatment with a combination of these substances can achieve the greatest possible effect.
• the inert plasticizing additive is preferably present on the surface of the grain in not more than 0.1% by weight, in particular in a range of 0.01-0.1% by weight. It is precisely with these quantities of the inert plasticizing additive that the change in the muzzle velocity and also the increase in pressure on transition to high temperatures are relatively small. With significantly larger amounts of the inert plasticizing additive, the possibility of achieving temperature-neutral behavior decreases.
• the grains for the drive preferably have a circular cylindrical geometry with longitudinal channels in the axial direction.
• the number of channels is arbitrary, often one grain has one channel, 7 or 19 channels.
• Such a propellant charge powder, also called hole powder, is consequently pourable or free-flowing, and can thus be industrially filled into tubes.
• the ratio of length (L) to diameter (D) of the cylindrical grain has a value L / D - 0.25-5.
• the length of the circular cylinder is z. B. in the range of 0.3-10 mm and the diameter in the range of 0.3-10 mm.
• the invention is designed as a multi-hole powder, a geometry with a small pitch circle and thus a greater external wall thickness is preferred.
• the individual longitudinal channels of a drive powder have a hole diameter of 0.1-0.5 mm.
• the grain dimensions are typically smaller than when used for the drive. In addition, they often have a circular cylindrical geometry with a central longitudinal channel. You have z. B has an outside diameter of 1.3-1.7 mm, a length of 1.5-2.0 mm, an average wall thickness of 0.6-0.8 mm and a hole diameter of approx. 0.10 mm.
• the material for the powders can be in the form of strips or extruded directly into a specific shape suitable for guns. In this form it is particularly suitable for large-caliber ammunition.
• This typically includes shapes in which the width is much smaller (e.g. at least 5 times or at least 10 times) than the length and the thickness is in turn much smaller (e.g. at least 5 times or at least 10 times) than the width.
• the thickness is e.g. B. 1-2 mm, the width at z. B. 10 mm or more and the length at z. B. 100 - 150 mm.
• shaped bodies i.e. hollow cylindrical shapes for ammunition, in which the case is missing or has been replaced by the "shaped body” arranged behind the ignition, are also conceivable.
• the grain matrix can optionally contain further additives known per se.
• Sodium hydrogen carbonate CAS #: 144-55-8
• Calcium carbonate CAS #: 471-34-1
• Magnesium oxide CAS #: 1309-48-4
• Akardite II CAS #: 724-18-5
• Centralit I CAS #: 90-93-7
• Centralit II CAS #: 611-92-7
• 2-nitrodiphenylamine CAS #: 836-30-6
• diphenylamine CAS #: 122-39-4
• Additives such as lime, manganese oxide, magnesium oxide ( CAS #: 1303-48-4 ), Molybdenum trioxide ( CAS #: 1313-27-5 ), Magnesium silicate ( CAS #: 14807-96-6 ), Calcium carbonate ( CAS #: 471-34-1 ), Titanium dioxide ( CAS #: 13463-67-7 ), Tungsten trioxide ( CAS #: 1314-35-8 ) serve to protect the pipes.
• Compounds such as phthalic acid esters, citric acid esters or adipic acid esters are common plasticizers.
• the green grain that is to say the powder that is still untreated per se, can contain other known additives in the matrix, e.g. B. to improve the ignition behavior and to modulate the combustion behavior.
• a method for producing a powder according to the invention is characterized in that a solvent-containing powder dough based on nitrocellulose and a crystalline energy carrier based on nitramine in 1-30% by weight and an inorganic flash hider is produced.
• the solvent-based powder dough is then extruded into a green grain.
• the solvent is removed from this green grain and the surface of the green grain is treated with camphor as an inert plasticizing additive. Finally, the surface-treated green grain is dried.
• a powder according to the invention can be produced on existing production plants.
• the solid formulation components can, for example, be mixed with a solvent mixture.
• the resulting solvent-moist kneading dough can be kneaded in a kneader and then extruded to the desired geometry in a press.
• the extruded strands can be pre-dried and cut to the desired grain length.
• the solvent can then be removed from the grain.
• the grain is with the inert surface-treated plasticizing additive and can optionally be subjected to a finishing.
• the green grain is preferably surface-treated with ethanol and graphite, i.e. graphitized.
• the graphitization can be carried out as a single process step. However, it is also possible to apply graphite and ethanol to the green grain together with the inert plasticizing additive.
• the solvent is particularly preferably removed from the green grain using a moist air process.
• the green grain obtained by extrusion contains an inorganic flash hider in the grain matrix.
• the green grain should not be subjected to a bathing process in order to remove the solvent from the grain matrix, since otherwise the water-soluble inorganic flash hider would be washed out of the grain matrix.
• the solvent that was used in the manufacturing process is therefore removed by means of a humid air process.
• the solvent-moist green grain is flowed through for 10-60 hours with a stream of air at temperatures between 20-70 ° C, which is saturated with water vapor, at high flow rates of several hundred m 3 per hour.
• the proportion of solvent is reduced to ⁇ 1%, while the water-soluble flash hider is not removed from the grain matrix, but remains there.
• finishing is carried out. This means in particular the careful drying and sieving of the surface-treated grain.
• various additives are added to the powder dough, which is based on nitrocellulose, ie the additives are evenly distributed in the matrix.
• the total amount of these additives is 0-10% by weight compared to nitrocellulose, preferably 2-7% by weight.
• the total amount of the crystalline nitramine compound, which is typically RDX, is 1-30% by weight of the amount of nitrocellulose.
• the crystalline nitramine compound may have to be subjected to a pretreatment to improve the connection to the matrix before it is added to the powder dough.
• the green grain is extruded through a die.
• the water and the solvent are then removed, preferably by means of moist air drying.
• the green grain is subjected to a surface treatment in which the inert plasticizing additive and preferably other additives such as graphite are applied in the presence of ethanol (impregnation + coating).
• the extruded strands are short pre-dried in air, cut to the desired length, and the green grain thus obtained fine mesh screens designed uniformly the green grain is then for 30 hours with a water-saturated air stream of 200 m 3 / h and a temperature of 30 ° C and then flowed through for 30 hours with an air stream of 400 m 3 / h and a temperature of 65 ° C (moist air drying).
• 0.05% by weight of graphite and 1.2 liters of ethanol are then added to 60 kg of the green grain heated to 60 ° C. in a copper polishing drum heated to 55 ° C., then allowed to act for 1 hour while rotating continuously.
• the powder is spread out on metal sheets and dried at 60 ° C. for 24 hours.
• Example 2 - drive powder 2 (FM 4650/22)
• a powder dough according to Example 1 is pressed (i.e. extruded) through a die with 7-hole geometry and 4.8 mm strand cross-section.
• the extruded strands are briefly pre-dried in the air, cut to the desired length, and the green grain thus obtained is subjected to moist air drying (as described in Example 1).
• 60 kg of the green grain are preheated to 60 ° C. and transferred to a copper polishing drum heated to 55 ° C. 0.05% of graphite and a solution of 1% by weight of camphor in 1.2 kg of ethanol are added to the green grain and it is continuously rotated for 1 hour.
• the powder is spread out on metal sheets and dried at 60 ° C. for 24 hours.
• the resulting drive powder 2 with the designation FM 4650/22 has the following physical properties: 3.42 mm outside diameter, 3.45 mm length, 0.71 mm mean wall thickness and 0.19 mm hole diameter, 4152 J / g heat content and 1002 g / l bulk density. Chemical stability: Deflagration temperature - 172 ° C. Heat flow calorimetry according to STANAG 4582 - 47 J / g resp. 30.9 ⁇ W (rement according to standard STANAG 4582: maximum heat development ⁇ 114 ⁇ W).
• a powder dough according to Example 1 is extruded through a die with 7-hole geometry and 5.1 mm strand cross-section.
• the extruded strands are briefly pre-dried in the air, cut to the desired length, and the green grain thus obtained is subjected to moist air drying (as described in Example 1).
• 120 kg of the green grain are preheated to 60 ° C. and transferred to a copper polishing drum heated to 55 ° C.
• the green grain is mixed with 0.05% graphite and a solution of 0.1% by weight camphor in 2.4 kg of ethanol and rotated continuously for 1 hour.
• the powder is spread out on metal sheets and dried at 60 ° C. for 24 hours.
• Example 4 Ignition powder 1 (FM 4483/21)
• a powder dough according to Example 1 is pressed (ie extruded) through a die with 1-hole geometry and 2.1 mm strand cross-section.
• the extruded strands are briefly pre-dried in the air, cut to the desired length and the resulting green grain is subjected to moist air drying (as described in Example 1).
• 20 kg of the green grain are preheated to 60 ° C and placed in a polishing drum heated to 55 ° C transferred from copper.
• 0.3% by weight of graphite and 0.3 kg of ethanol are added to the green grain, after which it is left to act for 1 hour while rotating continuously.
• the powder is spread out on metal sheets and dried at 60 ° C. for 24 hours.
• Example 5 Ignition powder 2 (FM 4483/22)
• a powder dough according to Example 1 is pressed (i.e. extruded) through a die with 1-hole geometry and 2.1 mm strand cross-section.
• the extruded strands are briefly pre-dried in the air, cut to the desired length, and the green grain thus obtained is subjected to moist air drying (as described in Example 1).
• 20 kg of the green matter are preheated to 60 ° C. and transferred to a copper polishing drum heated to 55 ° C. 0.3% by weight of graphite, 0.5% by weight of camphor and 0.15 kg of ethanol are added to the green grain, and the mixture is then left to act for 1 hour while rotating continuously.
• the powder is spread out on metal sheets and dried at 60 ° C. for 24 hours.
• the presence of 0.5% by weight of camphor in the ignition powder 2 according to the invention reduces the peak gas pressure at 21 ° C., which can be advantageous for certain applications.
• the igniter powder 2 with 0.5% by weight of camphor shows a higher pressure increase than that without camphor.
• the optimal amount of camphor must be carefully weighed so that the system requirements specified by the application can be met as best as possible.
• the M48 ball powder that has been introduced has the highest gas pressure at 21 ° C. The pressure increase from 21 ° C. to 63 ° C. is significantly higher with the introduced M48 ball powder of approx. 2300 psi compared to the two ignition powders 1 and 2 according to the invention.
• nitrocellulose-containing powders according to the invention are suitable as drive powders or igniter powders, which contain a crystalline energy carrier based on nitramine and an inorganic flash hider, and have small amounts of an inert plasticizing additive on the surface, for accelerating projectiles for mortar systems show a temperature-independent behavior and can therefore be used regardless of climatic conditions.

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• 2013
  • 2013-01-29 US US14/760,643 patent/US20150321969A1/en not_active Abandoned
  • 2013-01-29 WO PCT/CH2013/000017 patent/WO2014117280A1/de active Application Filing
  • 2013-01-29 EP EP13704344.4A patent/EP2951137B1/de active Active
  • 2013-01-29 CA CA2899260A patent/CA2899260C/en active Active
  • 2013-01-29 JP JP2015555513A patent/JP6165269B2/ja active Active
  • 2013-01-29 PL PL13704344T patent/PL2951137T3/pl unknown
  • 2013-01-29 ES ES13704344T patent/ES2872299T3/es active Active
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