Classifications

• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B21/00—Nitrogen; Compounds thereof
  • C01B21/082—Compounds containing nitrogen and non-metals and optionally metals
  • C01B21/087—Compounds containing nitrogen and non-metals and optionally metals containing one or more hydrogen atoms
• • 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
  • 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
  • C06B31/00—Compositions containing an inorganic nitrogen-oxygen salt
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/16—Nitrogen-containing compounds
  • C08K5/32—Compounds containing nitrogen bound to oxygen

Definitions

• the invention relates to a method of producing particles, prills, of ammonium dinitramide (ADN). More specifically, the invention concerns a method of producing in liquid phase ADN prills intended to be mixed with a polymer system.
• ADN ammonium dinitramide
• Ammonium dinitramide is an energetic oxidiser which can be used in many applications.
• One application is that as oxidiser in rocket propellents, which is disclosed in e.g. US 5,498,303.
• Advantages of using ADN in composite propellants instead of ammonium nitrate are described in, for instance, US 5,498,303 and WO 97/06099.
• the product When producing ADN, the product is obtained in the form of crystal aggregates which are not very suited to be directly mixed with a polymer system for producing a composite propellant. It is therefore desirable to produce prills of ADN. Prills allow a simpler handling system and result in a better rheology in mixing with polymer systems.
• prills in liquid phase are previously known.
• the substance is molten and dispersed to droplets in a liquid phase which is inert in relation to the sub- stance.
• the liquid phase is cooled to solidify the droplets into prills, and these are separated from the liquid phase.
• Such a method for prilling of ADN is mentioned in Challenges in Propellants and Combustion - 100 Years after Nobel (Conference Proceedings, 1996, pp 627-635); May Lee Chan et al: ADN Propellant Technology.
• a problem is that the particles must be washed clean with an organic solvent before they can be used in the production of propellants.
• An object of the present invention is to produce ADN prills which can be directly mixed with a polymer system without any preceding washing of the particles. This is achieved by a method as defined in the appended claims.
• the invention comprises melting and dispersion of ADN in a nonpolar medium to obtain droplets of ADN in the medium; cooling of the medium to solidify the droplets into prills and separation of said prills from the medium.
• Characteristic of the invention is that the nonpolar medium essentially consists of a plasticiser which is com- patible with said polymer system.
• the nonpolar medium may contain a polymer for adjusting the viscosity of the medium.
• the polymer can be, for instance, HTPB or some other polymer which is used in composite propellants and plastic-bonded explosives.
• a suitable viscosity of the nonpolar medium is 10-250 mPas.
• a small amount of surfactant can advantageously be added to the nonpolar medium.
• the surfactant makes the prills have a smooth and nice surface.
• the added amount is normally smaller than 5% by weight based on the nonpolar medium.
• Suitable surfactants are, for instance, laurylium sulphate, stearyl alcohol, sodium stearate, octylamine and dodecylamine.
• Suitable plasticisers are DOS, DOA, vacuum oil, transformer oil, K-10, BTTN, M/E- NENA, TMETN, Me-NENA, Et-NENA, WM3, FEFO, BDNPF/A, DANPE, DINA, and GAPA. K-10 up to and including GAPA are all energetic plasticisers.
• the prills can be directly mixed with a polymer system when producing composite propellants and plastic-bonded explosives without the particles first needing to be washed.
• the plasticiser and, where appropriate, the viscosity-controlling polymer are selected in consideration of the polymer system with which the prills are to be mixed.
• the plasticiser also protects the particles from the humidity of the air.
• Prilling was carried out in a 1 -litre stainless steel batch reactor consisting of a cylindrical container with a tight cover.
• the container was provided with a propeller agitator and baffles.
• the container was enclosed by a jacket to be passed by a heating medium and a cooling medium, respectively.
• Through the cover there was arranged a connection for a vacuum pump to evacuate gases from the medium.
• the reactor was supplied with 5 g of ADN, 700 ml of plasticiser (DOS, dioctyl sebacate) as a nonpolar medium and 200 mg of surfactant (laurylium sulphate).
• the reactor was closed and gases were evacuated by means of the vacuum pump.
• the mixture was heated to 96°C and kept at this temperature for 5 min during stirring by means of the propeller agitator at a rate of 60 rpm.
• the mixture was then quickly cooled to 20°C.
• the resulting prills were filtered off by suction filtration on a paper filter.
• the prills had a particle size of about 200 ⁇ m.
• the stirring intensity was increased, whereby prills having a particle size of about 120 ⁇ m were produced.
• prills were mixed with a polymer system (HTPB) without any preceding washing, and propellant elements were prepared.
• HTPB polymer system
• Propellant elements of high strength were obtained after hardening, without any problems.
• Example 1 The reactor according to Example 1 was provided with an anchor agitator instead of the propeller agitator and new prillings were earned out in the same way as in Example 1 , but with the following changes:
• a nonpolar medium use was made of a mixture of DOS and HTPB (Krasol® supplied by Kaucuk A.S.). 24.5 g of HTPB were mixed with DOS to a total volume of 300 ml. 20 g of ADN were added. The stirring rate was 400 rpm.
• Example 3a was repeated with a nonpolar medium consisting of a mixture of 31.5 g of HTPB and DOS to a total volume of 300 ml. The stirring rate was 600 rpm. The product was filtered off and mixed with a polymer system (HTPB) without any preceding washing, and propellant elements were prepared. Propellant elements of high strength were obtained after hardening, without any problems.
• a nonpolar medium consisting of a mixture of 31.5 g of HTPB and DOS to a total volume of 300 ml.
• the stirring rate was 600 rpm.
• the product was filtered off and mixed with a polymer system (HTPB) without any preceding washing, and propellant elements were prepared. Propellant elements of high strength were obtained after hardening, without any problems.
• HTPB polymer system
• Example 3 b was repeated with a stirring rate of 800 rpm. Prills of good quality with a size distributed around 60 ⁇ m were produced.
• Example 3c was repeated with 30 g of ADN in the nonpolar medium. In this case, the prills became smaller than in -Example 3c and were of good quality.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Inorganic Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Processes Of Treating Macromolecular Substances (AREA)
• Peptides Or Proteins (AREA)
• Apparatus Associated With Microorganisms And Enzymes (AREA)

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• 1997
  • 1997-10-28 SE SE9703928A patent/SE512396C2/sv not_active IP Right Cessation
• 1998
  • 1998-10-27 AU AU97716/98A patent/AU9771698A/en not_active Abandoned
  • 1998-10-27 WO PCT/SE1998/001936 patent/WO1999021793A1/sv active Application Filing
  • 1998-10-27 WO PCT/SE1998/001937 patent/WO1999021794A1/sv active Application Filing
  • 1998-10-27 AU AU97715/98A patent/AU9771598A/en not_active Abandoned
  • 1998-10-27 WO PCT/SE1998/001938 patent/WO1999021795A1/en active Application Filing
  • 1998-10-27 AU AU97717/98A patent/AU9771798A/en not_active Abandoned

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