SPECTRAL PYROTECHNICAL COMPOSITIONS FOR THERMAL COUNTERMEASURES OF FLARE TYPE AND PROCESS FOR PREPARING THE SAME

• Main Authors: CRISTEA VALENTIN, CÂRCEANU IRINA, MARIN ALEXANDRU, BOTIS HORIA-RĂZVAN, EPURE CRISTIANA, TIGANESCU TUDOR VIOREL, IORGA GEORGE OVIDIU, MUNTEANU MIHAIL, FRĂŢILĂ CĂTĂLIN
• Format: Patent
• Language: English; Romanian
• Published: 30.08.2024
• Subjects: CHEMISTRY; EXPLOSIVES; EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; MATCHES; METALLURGY; USE OF SINGLE SUBSTANCES AS EXPLOSIVES

The invention relates to spectral pyrotechnic compositions for making flare-type aerial thermal countermeasures and to a method for preparing them. According to the invention, the pyrotechnic composition consists of the following components, expressed in percentage by weight: a. 35...55% potassium perchlorate with a granulation <90 μm used as oxidant, b. the fuel consists of 20...45% Mg-Al alloy Magnalium with a granulation <63 μm or Al powder with a granulation of 4...5 μm, or a mixture of Mg powder with a granulation <63 μm with Al powder with a granulation of 4...5 mu m mixed in a ratio 50:50, c. 2...8% di-butyl phthalate, di-octyl phthalate, di-isooctyl phthalate, di-isononyl phthalate, di-butyl maleate, di-isobutyl maleate used as plasticizers, d. 10...15% polyurethane binder consisting of polyol based on solvent-free castor oil and aromatic polyisocyanate based on solvent-free di-phenyl-methane-diisocyanate, e. 2...8% halogenated binder which can be Teflon - polytetrafluoroethylene powder (C2F4)2, Viton powder - fluorinated copolymer of hexafluoropropene or tetrafluoroethylene with vinyl or vinylidene fluoride, chlorinated rubber powder with the degree of chlorination between 40...60% - monocomponent system and f. 3...6% acetone of 99.5% purity as organic solvent. According to the invention, the preparation method consists in drying the potassium perchlorate at 80°C for 24 hours, followed by sieving it through a sieve with a mesh size of max. 300 μm, after which a homogeneous mixture of metal powders, organic binder and plasticizer is prepared, over which the potassium perchlorate is added while stirring lightly, then the acetone and the polyurethane binder are added, and the whole mixture is homogenized in a mixer with screws and baffles, the polyurethane binder being prepared separately by mixing the polyol with the polyisocyanate, no later than 15 minutes before addition, after which the resulting homogeneous mixture is poured into moulds where it is stored for 24 hours.