Patent Application
20240010578
The present invention relates to non-toxic smoke-producing compositions for producing colored smoke. In particular, the smoke-producing compositions are free from chlorinated compounds and organic dyes from the family of anthraquinone (or derivatives). The smoke-producing compositions can be used to prepare pyrotechnic devices suitable for use in the military and civilian field.
Smoke-producing compositions for producing colored smoke generally comprise an oxidizing/reducing couple and an organic dye in powder form. The production of colored smoke from such compositions is based on a principle of sublimation. During the combustion of the oxidizing/reducing couple, the heat generated by the combustion causes the organic dye to change from the solid state to the gaseous state. Colored smokes are generated when the organic dye condenses in the atmosphere.
A large number of the organic dyes used in smoke-producing compositions are dyes from the family of anthraquinone (or derivatives) (polycyclic aromatic hydrocarbons, PAHs) which allow the generation of yellow, red, blue or green smokes. Some of these derivatives have or may have a risk to the environment or human health. Moreover, when the compositions comprise organic dyes whose decomposition temperature is less than the combustion temperature of the oxidizing/reducing couple, the dye can be destroyed and generate more or less toxic combustion entities. In compositions containing potassium chlorate as a reducing agent, these entities can be associated with chlorine atoms and possibly form molecules of the dioxin type. Dioxins, like polycyclic aromatic hydrocarbons, are classified as persistent organic pollutants (POPs). In order to protect human health and the environment against POPs, manufacturers aim at reducing their unintentional production.
However, the production of smoke-producing compositions that do not have a risk to the environment or to human health remains a challenge. Thus, the simple substitution of a component, the use of which may be controversial, by a component that does not have the aforementioned disadvantages does not prove to be easy given the number of requirements which the components of such compositions must meet in order to allow the production and marketing of high-performance smoke-producing compositions. Thus, the smoke-producing compositions for producing colored smoke must be stable over time and withstand climatic variations, in particular high temperature variations. They must have an acceptable burn time and smoke efficiency. In addition to non-toxicity for humans, they must also meet a large number of environmental requirements (non-toxicity, compliance with REACH regulations, limitation of non-biodegradable inert waste from firing).
Thus, a need remains for the provision of high-performance non-toxic smoke-producing compositions which allow to meet the above requirements and which do not contain organic dyes liable to generate POPs, in particular which do not contain organic dyes from the family of anthraquinone (or derivatives) and which are free from chlorinated compounds.
The present invention relates to a smoke-producing composition comprising, relative to the total weight of the composition:
The present invention also relates to a pyrotechnic device comprising such a smoke-producing composition as well as to its use for civil or military use.
Other aspects of the invention are as described below and in the claims.
The research carried out by the inventors has allowed to develop smoke-producing compositions that meet the need expressed.
The smoke-producing compositions of the present invention comprise
Such smoke-producing compositions have good technical performance: such as good combustion efficiency, good smoke density and pure color. Thus, the smoke-producing compositions of the present invention offer a very good combustion efficiency. Thus, combustion efficiencies above 45% are considered good and above 60% are considered very good. Such efficiencies allow the colored smoke to be visible over 5 km away in calm weather. The smoke density is greater than 5 g/cm3. Thus, the compositions of the present invention allow to obtain excellent smoke densities (greater than 5 g/cm3). The color of the smokes is characterized by measuring the colorimetry (Cylab coordinates) just for information.
Moreover, the smoke-producing compositions of the present invention are advantageously free from components listed to date in Annexes XIV and XVII of the REACH regulations and do not belong to the raw materials classified as toxic (bearing the mentions H314, H318, H300, H310, H311, H330, H331, H370, H372, H334, H350, H340, H360, H410 and H420). The absence of such components, in particular of toxic dyes, limits the risks for users exposed in the shorter or longer term to the smokes generated. Thus, the use of the compositions of the present invention does not have any known risks for human health and the environment.
The absence of dyes from the family of anthraquinone (or derivatives) and the absence of chlorine in the formulation of the smoke-producing compositions of the present invention allows to limit the production of harmful entities during their combustion and the production of non-biodegradable inert waste.
Advantageously, the smoke-producing compositions of the present invention do not comprise chlorinated components. The combustion entities generated therefore do not comprise chlorinated compounds, for example in the form of dioxins.
In the present description, unless explicitly stated otherwise, the term “a” designates one or more.
The smoke-producing compositions of the present invention comprise from 24 to 52% by weight, relative to the total weight of the composition, of potassium nitrate (KNO3) as oxidant. In some embodiments, the smoke-producing compositions comprise from 26 to 48% by weight of potassium nitrate.
The smoke-producing compositions of the present invention comprise from 15 to 40%, or from 18 to 35% by weight, relative to the total weight of the composition, of a reducing agent selected from the group consisting of dextrose, lactose, sucrose, dextrin, starch and mixtures thereof. In some embodiments, the smoke-producing compositions comprise from 18 to 35% by weight of a mixture of reducers. In some embodiments, the reducing agent is sucrose or starch.
The smoke-producing compositions of the present invention comprise from 6 to 60% by weight, relative to the total weight of the composition, of a non-salified sublimable organic dye in powder form. In some embodiments, the smoke-producing compositions comprise from 10 to 45% by weight of a non-salified sublimable organic dye in powder form.
The term “sublimable organic dye” refers to the ability of a dye to transition directly from the solid state to the gaseous state.
The term “non-salified” indicates that the organic dye is not in the form of a salt, such as a dye in monosodium or disodium form.
The sublimable organic dyes suitable for use in the context of the present invention must have a decomposition temperature higher than the combustion temperature of the smoke-producing composition. Their decomposition temperature must also be higher than their sublimation temperature.
The combustion temperatures of the smoke-producing compositions of the present invention vary according to the oxidizing/reducing couple selected. Thus, the combustion temperatures of the smoke-producing compositions may be as follows:
Organic dyes therefore have a decomposition temperature higher than 300° C. or higher than 350° C. or higher than 450° C.
The sublimable organic dye comes in the form of a powder. Preferably, the particles making up the powder are not nanoparticles, they do not have a nanometric size (1 to 100 nm). The absence of nanoparticle organic dyes limits the health risks for users exposed to the smokes generated. Preferably, the size of the particles does not exceed 200 μm. Such particles provide better dispersion in the smoke cloud.
Thus, preferably, the sublimable organic dye is in the form of a powder whose particles have a size greater than 1 μm, generally a size varying from 6 to 200 μm as measured by counting under a microscope (zoom ×84). It is understood that, within this range, the average particle size may vary depending on the organic dye selected.
The examples of specific dyes useful in the present invention are referred to by their generic name as referenced in the “Color Index International” database (2020).
An example of dyes from the thioxanthene family, suitable for use in the context of the present invention includes the dye Solvent Yellow 98.
Examples of dyes from the nitrobenzamine family, suitable for use in the context of the present invention include the dyes Pigment Yellow 65 and Pigment Green 8.
An example of dyes from the perylene family, suitable for use in the context of the present invention includes the dye Solvent Green 5.
Examples of dyes from the benzimidazole family, suitable for use in the context of the present invention include the dyes Solvent Red 196 and Pigment Red 194.
Examples of dyes from the naphthol family, suitable for use in the context of the present invention include the dyes Solvent Yellow 14, Solvent Red 24, Solvent Red 25, Solvent Red 26, Solvent Red 27, Pigment Red 1, Solvent Red 164, Solvent Yellow 56 and Pigment Red 170.
Examples of dyes from the terephthalate family, suitable for use in the context of the present invention include the dyes Solvent Yellow 155 and Pigment Yellow 175.
Examples of dyes from the phthalocyanine family, suitable for use in the context of the present invention include the dyes Solvent Blue 70 and Solvent Blue 67.
Examples of dyes from the violanthrone family, suitable for use in the context of the present invention include the dyes Vat blue 20, Vat green 1, Vat blue 16 and Vat green 2 (also called Pigment Green 54).
An example of a dye from the xanthene family, suitable for use in the context of the present invention includes the dye Solvent Green 4.
Examples of dyes from the pyrazolinone family, suitable for use in the context of the present invention include Vat Blue 5, Solvent Yellow 16, Pigment Yellow 154, Pigment Yellow 175 and Solvent Yellow 93.
Examples of dyes from the azobenzene family, suitable for use in the context of the present invention include Solvent Yellow 14, Solvent Red 24, Solvent Red 25, Solvent Red 26, Solvent Red 27, Pigment Red 1, Solvent Yellow 56 and Solvent Red 164.
Thus, in some embodiments, the non-salified sublimable organic dye is selected from the group consisting of Solvent Green 4, Pigment Yellow 65, Pigment Green 8, Solvent Green 5, Solvent Red 196, Pigment Red 194, Solvent Yellow 14, Solvent Red 24, Solvent Red 25, Solvent Red 26, Solvent Red 27, Pigment Red 1, Solvent Yellow 56, Solvent Red 164, Pigment Red 170, Solvent Yellow 155, Pigment Yellow 175, Solvent Yellow 98, Solvent Blue 70, Solvent Blue 67, Vat Blue 20, Vat Green 1, Vat Green 2, Vat Blue 16, Vat Blue 5, Solvent Yellow 16, Pigment Yellow 154, Pigment Yellow 175, Solvent Yellow 93, Pigment Blue 66, Solvent Blue 2, Solvent Red 179 and mixtures thereof.
In some embodiments, the organic dye is selected from the group consisting of Solvent green 5, Pigment Red 194, Solvent Red 24, Solvent Red 25, Solvent Red 26, Solvent Red 27, Solvent Yellow 56, Solvent Yellow 14, Vat Green 2, Solvent Yellow 98, Solvent Yellow 16, Solvent Yellow 93, Pigment Blue 66, Solvent Red 179 and mixtures thereof. Such organic dyes have a decomposition temperature higher than the combustion temperature of the smoke-producing composition and higher than their sublimation temperature. Such organic dyes do not have toxicity. Thus, the smoke-producing compositions comprising such dyes do not represent a danger for humans exposed in the shorter or longer term to the generated smokes.
The smoke-producing compositions of the present invention may further comprise additives commonly employed in the technical field, such as binders, phlegmatizers, moisture absorbers, combustion regulators, flame inhibitors and mixtures thereof.
In some embodiments, the smoke-producing compositions comprise from 0.5 to 10%, preferably from 5 to 10%, by weight relative to the total weight of the composition, of a phlegmatizer and/or from 0.5 to 8%, preferably from 1 to 3%, relative to the total weight of the composition, of a binder and/or from 0.5 to 10% by weight, preferably from 5 to 10%, relative to the total weight of the composition, of a flame inhibitor.
The smoke-producing compositions of the present invention may comprise from 1 to 18% by weight of optional additives relative to the total weight of the composition. The sum of the percentages by weight of oxidant, reducer, organic dye and optional additives is then equal to 100%.
Examples of binders suitable for use in the context of the present invention include gum arabic, epoxy resin, shellac and polyethylene wax.
Examples of phlegmatizers suitable for use in the context of the present invention include talc, kaolin (white clay made from aluminum silicate), kieselguhr, micronized silica and realgar.
Examples of combustion regulators suitable for use within the context of the present invention include hydrated alumina, paranitraniline, graphite and auramine N65.
Examples of flame inhibitor suitable for use in the context of the present invention include sodium hydrogencarbonate and calcium carbonate.
The person skilled in the art, on the basis of his technical knowledge, will be able to select the components and proportions of the components of the composition in order, for example, to reconcile chemical compatibility, volume ratio between pyrotechnic composition (oxidant, reducer and additives) and dyes (depending on the density of the dyes) and/or combustion rate. In particular, the person skilled in the art will be able to select the reducer/oxidant/dye combination delivering the best performance.
In some embodiments, the dye Solvent Yellow 93 will preferably be used in combination with starch as a reducing agent.
In some embodiments, the smoke-producing compositions of the present invention comprise:
The proportions of oxidant, reducer, organic dye and additives are chosen so that the sum of the percentages is equal to 100%.
In some embodiments, the smoke-producing compositions of the present invention comprise:
In these embodiments, the sublimable organic dye can be as described above.
The smoke-producing compositions of the present invention can be produced according to methods well known to the person skilled in the art. Thus, the method described in the “Examples” section can easily be transposed on a large scale.
The smoke-producing compositions of the present invention can be used to produce pyrotechnic devices generating colored smoke, such as colored smoke grenades, signaling smokes (for example SNCF signals), training smokes, etc.
Thus, the present invention also relates to pyrotechnic devices comprising a smoke-producing composition according to the present invention.
The smokes generated can be yellow, red, blue or green depending on the use and the needs.
Pyrotechnic devices can be used in the civilian (for example paintball, demonstration, football match, . . . ) or military field.
They can allow to make position marking, to alert or to inform according to the color of the smoke.
The following examples are given for illustrative purposes, but should in no way be considered as limiting the present invention.
The technical performance of the smoke-producing compositions, such as the density of the smoke, the duration of combustion, the combustion efficiency and the intensity of the color of the smoke are evaluated at room temperature (20-25° C.) in an experimental device comprising:
The produced models are weighed before and after combustion, thus allowing to determine the mass of the composition before combustion (masscomposition before combustion) and the mass of the composition after combustion (masscombustion residue).
The smoke density (d), expressed in grams per cubic centimeter, is determined by the following relationship:
The combustion time is measured by means of the camera.
The combustion efficiency, expressed as a percentage, is determined by the following relationship:
Colorimetry allows to characterize a color by numerical values L*a*b* (CIELAB). L*a*b* color space (CIELAB) is a system adopted by the International Commission on Illumination in 1976.
L* a* b* are measured in the space
The evolution or color difference (DE) can be followed by the relationship:
DE=[(DL*)2+(Da*)2+(db*)2]1/2
where DL*, Da*, db* are the color difference values between the sample and the reference.
The color intensity is measured by a colorimeter disposed directly on the fume recovery filter (sublimated dye deposition on the filter).
The smoke-producing compositions were produced from the following raw materials:
The formulations of the smoke-producing compositions produced are as presented in Table 1. The percentages indicated are percentages by weight expressed relative to the total weight of the smoke-producing composition.
33%
35%
37%
The smoke-producing compositions were produced according to the detailed protocol presented below.
The performance of the smoke-producing compositions was evaluated according to the methods described above. The results are shown in Table 2.
The smoke-producing compositions of the present invention are non-toxic and effective.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2012672 | Dec 2020 | FR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/FR2021/052208 | 12/3/2021 | WO |
