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
  • C06C—DETONATING OR PRIMING DEVICES; FUSES; CHEMICAL LIGHTERS; PYROPHORIC COMPOSITIONS
  • C06C15/00—Pyrophoric compositions; Flints

Definitions

• the invention relates to illuminating compositions intended for use in pyrotechnic articles such as Bengal lights, signal flares or party devices, such compositions comprising a binder, a solid oxidant, an emissive compound and possibly a fuel. metallic.
• Illuminating pyrotechnic compositions produced from polymerizable organic binders are known and most of these compositions have been formulated in order to obtain an intense luminosity, which requires the use of a high level of a metallic fuel for combustion. bright like magnesium.
• These formulations most often lead to compositions in which the flame emits only an impure coloring, the luminous efficacy of magnesium being greater than the luminous efficacy of emissive salts such as alkali or alkaline earth nitrates, and in which the combustion produces abundant smoke and rigid slag, which is particularly troublesome in certain applications such as the production of Bengal fires.
• the object of the present invention is to obtain an illuminating composition whose flame has a lively and pure coloring while obtaining very slow combustion speeds, less than 1 mm / second, which makes it possible to produce pyrotechnic articles of small bulk which generate a very colorful and very visible flame despite the relative decrease in the value of the luminous efficiency due to the absence of a metal with strong combustion, this decrease in the luminous efficiency being compensated by a more vivid and more pronounced coloring , by the significant reduction in fumes hampering the visibility of the flame, the porosity and the fragility of the slag produced allowing a better distribution of the emissive flame.
• the invention is characterized in that the proportion by weight of the assembly consisting of the solid oxidant and the emissive compound is between 75 and 90% of the total weight of the composition, the weight of the emissive compound being greater than the weight of the solid oxidant and the metal fuel rate being less than 5% of the total weight of the composition.
• the weight of the emissive compound is greater than one and a half times the weight of the solid oxidant.
• the polyurethane binder is produced from at least one triisocyanate reacting on at least one polyhydroxy compound, this compound preferably having no hydroxyl group on aromatic rings. It is possible to use a polyisocyanate and a hydroxylated compound in non-stoichiometric proportions, the excess of hydroxyl groups leading to a more flexible polyurethane, and it is also possible to use a known plasticizer, such as phthalate butyl, to soften the pyrotechnic composition.
• Polyurethanes which are particularly suitable in the context of the invention have been produced from polyisocyanates sold under the name "DESMODUR” which are products of the company BAYER, hydroxylated compounds such as castor oil and / or the product sold under the name "DESMOPHEN” by the company BAYER, making it possible to obtain satisfactory binders after polymerization at room temperature.
• DESMODUR polyisocyanates sold under the name "DESMODUR” which are products of the company BAYER
• hydroxylated compounds such as castor oil and / or the product sold under the name "DESMOPHEN" by the company BAYER
• the solid oxidant is preferably chosen from the group consisting of chlorates and perchlorates of alkaline character, that is to say chlorates and perchlorates of alkali, alkaline earth, or incidentally ammonium, and can be constituted by a single one of these oxidizing compounds or by a mixture of these compounds, the alkaline perchlorates being advantageously used for reasons of safety and efficiency, and potassium perchlorate being industrially the most suitable oxidizing compound.
• the emissive compound is preferably chosen from the group consisting of nitrates and alkali or alkaline earth emissive nitrites, that is to say essentially nitrates and nitrites of sodium, strontium or barium according to the desired coloration, and this emissive compound may consist of only one of these salts or a mixture of these salts.
• the pyrotechnic illuminating compositions according to the invention preferably do not contain metallic fuel such as magnesium, it is however possible to incorporate a small amount of such a metal, provided that the proportion by weight of the whole consisting of the oxidizing agent and the emissive compound is between 75 and 90% of the total weight of the composition, and it is advantageous for this metal with strong combustion to have a very fine particle size.
• composition No. 1 burns faster than composition No. 1 and therefore has a greater instantaneous luminosity, the slightly larger flame always having a bright red coloration.
• This composition has a much greater hardness than the previous compositions and burns with a well-colored yellow flame. Its hardness can be reduced by adding a plasticizer of the butyl phthalate type, but such an addition decreases the rate of combustion and must be limited to 4% by weight, since the composition then becomes too flexible.
• This composition is very flexible and greater hardness can be obtained by reducing the level of binder, such a reduction resulting in a slight increase in the rate of combustion.
• This composition burns with a bright red flame in approximately the same conditions as the previous composition.
• the burning rate is 0.5 mm / second and is therefore of the same order of magnitude as the combustion rate of the composition No. 4, but the flame has a greater coloring, the weight of strontium nitrate being in this case equal to 2.5 times the weight of potassium perchlorate, this more marked coloring being very noticeable as soon as this weight ratio is greater than 2.
• compositions according to the invention can be prepared by the implementation of conventional mixing processes without solvent, then casting or extrusion at low pressure, the polymerization being able to be carried out at room temperature.
• the low pressure extrusion or the injection in particular allow shaping directly inside an inhibitor tube which is deployed under the effect of the push of the injected composition.
• the inhibited cylinders thus obtained can be several meters in length and be cut off or cut into elements of different lengths, one of the sections being able to be subsequently inhibited in order to constitute, for example, a signaling torch or a Bengal light.
• the lighting pyrotechnic compositions according to the invention can be used for the production of all lighting pyrotechnic articles, both in the field of safety and signaling as in the field of fireworks display.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Metallurgy (AREA)
• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Dispersion Chemistry (AREA)
• Molecular Biology (AREA)
• Crystallography & Structural Chemistry (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Air Bags (AREA)

Applications Claiming Priority (2)

Publications (2)

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ID=9232948

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• 1979
  • 1979-12-19 FR FR7931127A patent/FR2471960A1/fr active Granted
• 1980
  • 1980-12-10 DE DE8080401771T patent/DE3065560D1/de not_active Expired
  • 1980-12-10 EP EP19800401771 patent/EP0032080B1/fr not_active Expired
  • 1980-12-15 ES ES497753A patent/ES497753A0/es active Granted

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