Classifications

• • 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
• • 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
  • C06B21/0008—Compounding the ingredient
  • C06B21/0025—Compounding the ingredient the ingredient being a polymer bonded explosive or thermic component
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21K—NON-ELECTRIC LIGHT SOURCES USING LUMINESCENCE; LIGHT SOURCES USING ELECTROCHEMILUMINESCENCE; LIGHT SOURCES USING CHARGES OF COMBUSTIBLE MATERIAL; LIGHT SOURCES USING SEMICONDUCTOR DEVICES AS LIGHT-GENERATING ELEMENTS; LIGHT SOURCES NOT OTHERWISE PROVIDED FOR
  • F21K5/00—Light sources using charges of combustible material, e.g. illuminating flash devices
  • F21K5/02—Light sources using charges of combustible material, e.g. illuminating flash devices ignited in a non-disrupting container, e.g. photo-flash bulb

Definitions

• the invention relates to a process for the production of plastic-bound explosives from crystalline explosives and / or crystalline inorganic oxidizers, energy-providing additives and a polyurethane binder applied from aqueous dispersion without the use of organic solvents, and to the explosives obtained in the process.
• Polyurethanes have the advantage that, in addition to good mechanical properties, they provide the explosives with above-average shock and bullet resistance and low mechanical sensitivity. described in the Encyclopedia of Explosives and Related Items explosives with a polyurethane content of 2.5 to 10%.
• the crystalline explosives are mixed with the polyurethane binder in most cases by the slurry method, in which the polyurethane binder is dissolved in a solvent and added to an aqueous dispersion of the explosive provided with protective colloids.
• the solvent is distilled off from the mixture, granules of the desired size can be produced.
• the reactive processes are known to start from liquid, hydroxy-terminated polyesters, ethers and butadienes which are crosslinked with isocyanates.
• the latter method is mainly used when one wants to obtain pourable explosive mixtures.
• Explosives are known from US Pat. No. 3,173,817 which are produced from an aqueous dispersion using a polyacrylate.
• the plastic dispersion is coagulated by adding inorganic salts and the resulting explosive granules are mechanically separated from the water and dried.
• the disadvantage of the process is the poor thermal stability of the acrylates and the risk of including inorganic coagulants, which have a negative effect on the stability of the explosive.
• the reproducible granulate formation, i.e. the production of a defined granulate, for pressing purposes is difficult.
• the granules have to be hot-pressed to ensure the desired properties of the compact.
• hot pressing is technically and economically very complex.
• the invention thus relates to a process for the production of plastic-bound explosives, the binder being applied from aqueous dispersions, which is characterized in that polyurethanes applied with the exclusion of organic solvents are used and the granules obtained are dried.
• novel, aqueous, aliphatic and / or aromatic polyurethane dispersions with a solids content of 30 to 40% are used.
• Such polyurethane dispersions are commercially available. They have particle sizes in the range from 0.1 to 0.4 ⁇ m and specific weights in the range from 0.9 to 1.2, preferably 1.1.
• the pH of these dispersions can vary and is generally in the range from 5 to 8. However, the pH of the polyurethane dispersions depends on their preparation and is for the invention. Process of no importance. Transparent, approximately 0.1 to 0.2 mm thick films produced from such commercially available aqueous dispersions have elongations at break, determined according to DIN 53504, more than 500% and also have high tensile strengths.
• Such aqueous polyurethane dispersions dry irreversibly to form highly elastic films which adhere perfectly to the explosive crystals.
• the thermal stability and the compatibility with explosives of the polymers according to the invention is comparable to that of the polyurethanes used to date, so that the advantages of the polyurethanes can be exploited without having the disadvantages of the complicated processing.
• the explosives obtained with the polymers according to the invention are already at pressures of less than 2000 bar very good cold press.
• the mechanical properties of the polymers can, if necessary, be adjusted in a simple manner by using highly polymeric, water-soluble plasticizers or reinforcing resins which are dissolved in the water of the dispersion in the manner according to the invention and filmed with the polyurethane.
• Polymeric plasticizers are therefore used to avoid the migration phenomena of the plasticizer observed in polymers plasticized with low molecular weight plasticizers.
• plasticizers e.g. Polyethylene glycols, polypropylene glycols, polyvinyl pyrollidone and polyvinyl methyl ether, but preferably polyethylene glycols with a molecular weight of at least 5000, which are water-soluble but not hygroscopic, and polyvinyl ether.
• Water-soluble reinforcing resins are epoxy resins, such as 3,4-epoxicyclohexylmethyl and 3,4-epoxicyclohexane carboxylate and the reaction product of pentaerythritol and epichlorohydrin, polymethoximelamines, polyethylene-maleic anhydride copolymers, polyacrylamide and phenolic resins.
• the mode of action of the reinforcement resins is different. While the epoxy resins are cured with a water-soluble hardener in parallel with the physical drying and film formation process of the polyurethane, the polyethylene-maleic anhydride copolymer co-films with the polyurethane to form films with increased mechanical strength.
• the polymethoximelamines, phenolic resins and the polyacrylamide are dissolved in the dispersion, but at the temperatures prevailing in the process during drying from 40 to 50 ° C. they become insoluble, crosslinked products which increase the strength.
• the proportion of plasticizers in the binder should be 0 to 30%, but preferably 5 to 15%, and that extrudable, elastoplastic explosive compositions can be produced within these limits.
• the proportion of reinforcing resins is primarily limited by their compatibility with the polyurethane and by their water solubility. The proportion should be 0 to 50%, but preferably 2 to 20%.
• Crystalline explosives that can be processed with the binder according to the invention must above all be water-insoluble. Therefore, all known crystalline, water-insoluble primary and secondary explosions substances to be used, such as, for example, hexogen, octogen, nitroguanidine, potassium and guanidine picrate, tetryl, diamino and triaminotrinitrobenzene, benzotrifuroxane, diaminohexanitrobiphenyl, hexanitrostilbene and pentaerythritol tetranitrate, the list not being a limitation.
• all known crystalline, water-insoluble primary and secondary explosions substances to be used such as, for example, hexogen, octogen, nitroguanidine, potassium and guanidine picrate, tetryl, diamino and triaminotrinitrobenzene, benzotrifuroxane, diaminohexanitrobiphenyl, hexa
• the proportion of the crystalline explosive in the total mass can be between 50 and 99.8% depending on the intended use, i.e. even the smallest amounts of binder can be applied without difficulty.
• Two methods can be used to produce the explosives according to the invention.
• Either the aqueous polyurethane dispersion is placed with the plasticizers or reinforcing resins and the water-moist explosive is mixed in a suitable mixer.
• This process is suitable for binder proportions of up to 8%, with the water component being controlled by adding water for smaller binder components.
• the moist explosive mass can now be safely granulated and dried. This process is known per se. With higher binder proportions, the mass becomes so pasty that mechanical granulation is eliminated. In this case, the binder and explosives are dispersed in a larger amount of water and the binder is coagulated. Granules are formed which are separated from the water and dried.
• the coagulation is carried out in such a way that, in order to avoid contamination by inorganic salts, coagulation is carried out with the polyvinyl methyl ether already described as a plasticizer.
• This material has the property of precipitating out of the aqueous solution in fine particles when heated and thus breaking the polyurethane dispersion.
• coagulation time can be set precisely by the proportion of phenolic resin, thereby achieving a controlled formation of granules. It is particularly advantageous that the grain size of the crystalline explosives and additives is not critical. For example, nitroguanidine with a grain size of 1 to 2 ⁇ m can be processed without difficulty into compressible granules, so that the use of complex, uncrystallized nitroguanidine can be dispensed with.
• the main advantage of the process according to the invention is that the process control and the mechanical equipment are simple and the safety is ensured by processing in the aqueous phase.
• Rubber-elastic compacts in the pressure range of 800 to 2500 bar can be produced with the same binder content, but with a different plasticizer content.
• the process is not limited to the production of the binder / explosive mixtures described, but also explosives can be produced from the binder according to the invention, organic crystalline explosives and inorganic salts as well as energy-supplying metal powders.
• These known salts can be perchlorates such as potassium perchlorate, nitrates such as barium nitrate, heavy metal oxides such as lead, iron and copper oxides.
• Metal powders can be aluminum, aluminum-magnesium alloys, silicon, titanium, zircon and tungsten.
• the binder can be adjusted so that the mixtures can be extruded cold or at a moderately elevated temperature and no solvents are required.
• Example 2 The granules from Example 1 were pressed at 1500, 2000 and 2500 bar at 20 ° C. to give shaped articles with a diameter of 30 mm.
• the density was 1.68, 1.71 and 1.735 g / cm 3 (98% of theoretical density).
• Example 2 The granules from Example 1 were subjected to a stability test at 120 ° C. (weight 2.5 g).
• the explosive has good thermal stability.
• the detonation speed was measured from compacts from Example 3. At a density of 1735 g / cm 3 , 8360 received m / sec.
• a nitroguanidine with an average grain size of 1.8 ⁇ m was processed according to the procedure of Example 1. Because of the low bulk density, the nitroguanidine was mixed in in three parts and an additional 6% water (in the total amount) was added.
• the mass obtained was excellent to granulate.
• the compressed density of the explosive reached at 2000 bar was 95% of theory at 1.6 g / cm 3 . Th.
• a suspension of 820 g of hexogen, 18 g of PEG 20,000 and 405 g (16.2%) of the aqueous polyurethane dispersion according to the invention was prepared by the procedure of Example 6. After adding 50 g of a 10% strength aqueous solution of polyvinyl methyl ether, the mixture was heated to 45 ° C. The dispersion coagulated and granules with a grain size of 1 to 2 ⁇ m were formed. The dried, very elastic granules were able to retain their shape at 50 ° C. Bodies are extruded.
• compositions of the invention are to be used as smokeless propellants.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Dispersion Chemistry (AREA)
• General Engineering & Computer Science (AREA)
• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Molecular Biology (AREA)
• Crystallography & Structural Chemistry (AREA)
• Processes Of Treating Macromolecular Substances (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Graft Or Block Polymers (AREA)
• Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)

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Publications (3)

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Cited By (10)

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• 1980
  • 1980-03-15 DE DE3010052A patent/DE3010052C2/de not_active Expired
• 1981
  • 1981-02-13 AT AT81101016T patent/ATE6497T1/de not_active IP Right Cessation
  • 1981-02-13 EP EP81101016A patent/EP0036481B1/fr not_active Expired
  • 1981-02-13 DE DE8181101016T patent/DE3162454D1/de not_active Expired
  • 1981-03-05 US US06/240,909 patent/US4405534A/en not_active Expired - Lifetime

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