CZ242995A3 - Pyrotechnic mixture for generating carbon-containing smokes masking in infrared region of radiation - Google Patents

Abstract

This smoke-producing pyrotechnic mixture contains 50 to 70 % by weight of anthacene or naphthalene and 30 to 50 % by weight of sodium perchlorate, perchlorate potassium or ammonium perchlorate. The mixtures are used to create mask smoke containing particles of carbon which are characterised by their high damping effect in the infrared area of electro-magnetic radiation absorbing infra-red radiation, in particular within the range of 0.78 to 14 micrometers.

Description

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The fuming pyrotechnic composition contains 50 to 70 wt. % anthracene or naphthalene and 30 to 50 wt. % sodium, potassium or ammonium perchlorate, or 70 to 85 wt. % tetrachloronaphthalene, 1 to 15 wt. % magnesium powder and 5 to 15 wt. % polyvinylidene fluoride. The compositions are intended to produce masking fumes containing carbon particles which are characterized by a high damping efficiency in the infrared region of the electromagnetic radiation absorbing infrared radiation, particularly in the range of 3 to 14 .mu.m.

CZ 2429-95 A3

Pyrotechnic mixture for creating carbon masking fumes

in the infrared range i

Technical field

BACKGROUND OF THE INVENTION The present invention relates to a pyrotechnic composition for generating an ointment smoke containing carbon particles with spectral attenuation efficiency in the infrared (IR) region of high-boiling hydrocarbon-based hydrocarbons with an oxidant and additives that absorbs IR radiation, particularly in the range of 3-14 gm.

BACKGROUND OF THE INVENTION

Many smoke-forming mixtures are known which have been used in fumigants in the military to prevent visual observation. With sufficient concentration in the cloud, the fumes produced from them perfectly masked and masked. With the development of modern optoelectronic reconnaissance equipment and high precision weapon guidance systems using IR radiation in the wavelength range from 0.78 to 14 gm, it was necessary to develop substances that would effectively mask and thus mask the smoke cloud objects and troops against them. Such fumes, in addition to their high camouflage properties and appropriate physicochemical properties, had to provide for minimum adverse hygienic and physiological effects.

Over the past two decades, it has been shown that aerodispersion of carbon particles can effectively obscure IR radiation in the art. Carbon aerosols exhibited forty times greater masking capability than fumes from standard pyrotechnic HC compositions producing preferentially zinc chloride aerodispersions. This was explained by a combination of 3-12 µm absorption of carbon on carbon and scattering on relatively large carbon particles.

Carbon aerodispersions can be formed from pyrotechnic compositions by burning them in fume means of suitable construction. In addition, it is possible to generate carbon aerodispersions from pyrotechnic compositions by dispersing suitably treated carbon dust impurities. Among the pyrotechnic compositions, two kinds of compositions are possible, namely high-boiling hydrocarbons and halogenated hydrocarbons. Some of these pyrotechnic compositions used to create black signal smoke (ELLERN, H.: Military and

Civilian Pyrotechnics. Chem. Publ. Comp. New York 1968. McLAIN, J.H .: Pyrotechnics. The Franklin Inst. Press. Phyladelphia 1980.) for marking purposes. Other pyrotechnic styles with halogenated hydrocarbons and with metals or metal oxides were used to create gray fumes for visible-field masking that were not effective in the IR field of radiation (KLUSÁČEK, L, - NAVRÁTIL, P.: Vojenské rozhledy 3, No. 6, 1994) in the wavelength spectrum from 0.78 to 14 µm.

SUMMARY OF THE INVENTION

These drawbacks are overcome by a pyrotechnic composition for generating a fume containing carbon particles with spectral attenuation efficiency in the infrared region of the high-boiling hydrocarbons with oxidant and additives, and the generated smoke absorbs infrared radiation in particular in the range of 3-14 µm.

This mixture contains 50-70 wt. % anthracene or naphthalene and 30-50 wt.% sodium, potassium or ammonium perchlorate, or 70-85 wt. % tetrachloronaphthalene, 1-15 wt. % magnesium powder and 5-15 wt. % polyvinylidene fluoride. The high masking effect of carbon aerodispersions in the wavelength spectrum of 0.78 to 14 µm produced by incomplete combustion of these pyrotechnic compositions is based on the strong absorption and dispersion of penetrating electromagnetic radiation by the particles of these carbon aerodispersions and thus making the masked object unrecognizable in the wavelength band.

The preparation of the smoke-forming pyrotechnic compositions is preferably carried out by mixing and subsequent pressing. This method of preparation ensures the desired homogeneity of the mixtures and allows the desired shape of the moldings. The technology of preparing such mixtures is safe. The pyrotechnic mixtures prepared in this way enable the transformation of fuming agents into an aerodisperse form with a higher efficiency than 85% and a storage stability in a closed state of at least 10 years.

In the compositions according to the invention, the effect of oxidizing agents in the combustion with the necessary heat release is utilized to produce carbon products having the desired properties. The aerodispersions produced are characterized by a mean particle size of 0.6-0.8 μπι and high masking efficiency values in the infrared range of radiation under normal field conditions with low atmospheric variability. Measured values of mean values · of radiation attenuation are shown in the following table.

Table: Average attenuation values L of carbon aerodispersions from pyrotechnic mixtures based on high-boiling hydrocarbons in the IR range under variable conditions

Base Average L (dB) at Áfpml mixture i 0.82 3-5 10.6 Anthracen 39.1 15.5 6.7 Tetrachlor- 39.8 17.2 13.0 naphthalene

The invention is illustrated by the following examples. ¹ j

DETAILED DESCRIPTION OF THE INVENTION

Example i. % potassium perchlorate was mixed with 48 wt. % anhracene. After thorough mixing of the components, the resulting material was pressed into moldings. A dyed-forming pyrotechnic composition was obtained from which the formed carbon aerodispersion exhibited high masking capability in the Infrared spectrum at wavelengths of 0.82, 3-5 and 10.6 µm.

Example 2 wt. % tetrachloronaphthalene was mixed with 12 wt. % magnesium powder and 6 wt. %. polyvinilidene fluoride. After thorough mixing of the components, the resulting material was pressed into segment moldings. A fuming pyrotechnic composition was obtained, from which the formed carbon aerodispersion showed high attenuation properties to radiation in the infrared region of the spectrum at 0.82, 3-5 and 10.6 µm wavelengths and laser wavelengths of this spectral region.

Industrial applicability

AND

The present invention can be used, in particular, in the military in smoke means to produce carbon aerodispersions through the smoke discharge of incomplete combustion products of reaction components of pyrotechnic compositions that mask objects, military equipment and units from the effects of modern optoelectronic reconnaissance and high precision weapon guidance systems its activity in the IR field of radiation in the wavelength spectrum from 0.78 to 14 pm.

Claims (2)

PATENT CLAIMS A fumigant pyrotechnic composition for generating a masking smoke comprising carbon particles with spectral attenuation efficiency in the infrared region of electromagnetic radiation based on high-boiling hydrocarbons or halogenated hydrocarbons with an oxidant and additives, which absorbs IR radiation, in particular in the range of 3-14 pm, characterized by containing 50-70 wt. % of anthracene or naphthalene and 30-50% by weight of sodium, potassium or ammonium chlorite. 2. A smoke-forming pyrotechnic composition according to claim 1, characterized in that it comprises 70-85 wt. % tetrachloronaphthalene, 1-15 wt. % magnesium powder and 5-15 wt. % polyvinylidene fluoride.