PLASTIC-BONDED PYROTECHNICAL MIXTURE FOR PRODUCING ALKALI METAL CHLORIDE OR EARTH ALKALI METAL CHLORIDE AEROSOLS AS SMOKESCREEN

Abstract

A plastic-bonded pyrotechnical mixture is provided that includes at least one oxidatizer, one carbonate and/or phosphate from the group of alkali metals or earth alkali metals, a chlorinated rubber and a softener. An additional bonding agent and/or graphite can be added thereto as needed. The oxidatizer can be a perchlorate or a mixture of perchlorates from the group of alkali metals or earth alkali metals, or alternatively, ammonium perchlorates can also be integrated as an oxidatizer. The softener is an organic substance or substance mixture from the group of adipates or phthalates, or can be an organic phosphoric acid ester or a phosphoric acid ester mixture. As an additional bonding agent, an organic titanate or an organic titanate mixture is preferred. All components are mixed with one another at such a ratio that a neutral smoke in the pH range of 5-7 (bases on aerosol) is created.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the generation and release of alkali metal chloride and alkaline earth metal chloride aerosols with smokescreen effect through the reaction of plastic-bound active pyrotechnic compositions, especially in the context of smoke grenades.

2. Description of the Background Art

Pyrotechnic mixtures for generating inorganic aerosols for military screening purposes often contain toxicologically objectionable substances. For simulation and training purposes, therefore, it is preferred to employ practice systems which release aerosols that are of low toxicity and are as far as possible pH-neutral (pH 5-7).

In the case of practice systems for smoke hand grenades, moreover, a requirement is that for a effective training they should not only generate a smoke of low toxicity but also should have the geometry and mass of the corresponding deployment versions.

In the case of grenades which generate a spontaneous smoke, the active pyrotechnic smoke composition is ignited by a break-up charge and delivered. A corresponding rapid smoke hand grenade based on a pyrotechnic charge which comprises red phosphorus is published in the form of DE 195 48 436 C1, which corresponds to U.S. Pat. No. 5,700,971.

For practice systems, in the case of the above-recited rapid smoke grenades, the active pyrotechnic compositions can be switched relatively easily for finely ground inorganic substance/mineral mixtures, which are then delivered via the break-up charge. For realistic training, in the area of the rapid smoke hand grenades, the compositions of the respective applications can be simulated well via the bulk density of the powderous substance/mineral mixtures and/or their compression in the prevailing volume.

In the case of nonspontaneous smoke grenades that generate condensation aerosols, the inorganic substances with smokescreen effect are generated from the active pyrotechnic composition present, after ignition. One such active pyrotechnic composition is published in the form, for example, of DE 27 43 363, which corresponds to U.S. Pat. No. 4,376,001.

For practice systems of the above-described smoke grenades which generate nonspontaneous condensation aerosols, pyrotechnic colored smoke charges or pyrotechnic charges with heating beds containing metal powder are used for expelling, for example, alkali metal chlorides, see DE 10 2008 010 942, which corresponds to US 20090211672, which is incorporated herein by reference. A problem which arises here in the area of hand grenades is that with the corresponding application systems it is possible to produce effective simulation only of those smoke hand grenades that have masses of more than 300 g.

With colored smoke devices or application systems in which, for example, alkali metal chlorides are expelled via heating beds containing metal powder, the specific construction means that the aerosols are blown out only in one direction, and this can lead to reduced output by the application systems under diverse climatic and geographical conditions; for example, the blowing-out of the aerosol in snow causes it to condense rapidly, resulting in a reduced smoke output.

The burning characteristics of active pyrotechnic smoke compositions which generate the inorganic substances that, in conjunction with atmospheric moisture, are effective as smoke, and do so only through reaction of these inorganic substances in the form of condensation aerosols, can be simulated only to a limited degree by application systems which utilize pyrotechnic heating beds for the sublimation of organic substances (colored smoke) or inorganic substances (e.g., alkali metal chlorides).

DETAILED DESCRIPTION OF THE INVENTION

The idea on which an embodiment of the invention is based, in analogy to the known condensation aerosol mist-generating active pyrotechnic compositions, is that of using a plastic-bound pyrotechnic mixture with which alkali metal chloride and/or alkaline earth metal chloride aerosols, which are of comparatively low toxicity and produce a smokescreen effect, are generated in situ by reaction. In addition to the corresponding perchlorates as a source of alkali metal chloride and/or alkaline earth metal chloride, the reaction of the proposed pyrotechnic mixtures comprising the chlorinated rubber present in conjunction with the alkali metal and/or alkaline earth metal carbonates and/or phosphates present additionally generates the corresponding alkali metal and/or alkaline earth metal chloride. All of the components are blended in a proportion to one another such that a neutral smoke in the range of pH 5-7 (based on aerosol) is formed.

A smoke charge having the above features of the invention contains for example: 56.7% by weight potassium perchlorate; 19.8% by weight potassium carbonate; 15.0% by weight polychloroisoprene; and/or 8.5% by weight plasticizer

In a development of the invention, the smoke effect of the active compositions can be enhanced by admixing ammonium perchlorate with the correspondingly required amounts of alkali metal and/or alkaline earth metal carbonates and/or phosphates. This effect is based on the additional release of steam, which promotes smoke condensation. In this way it is possible to respond to customer requirements with regard, among other things, to smoke performance, toxicity, and pH-neutrality of the aerosol, in a simple way.

A smoke charge in a development of the invention contains for example: 50.6% by weight potassium perchlorate; 11.6% by weight ammonium perchlorate; 14.3% by weight lithium carbonate; 15.0% by weight polychloroisoprene; and/or 8.5% by weight plasticizer

The heat released on the reaction of the active pyrotechnic composition serves for the sublimation of the aerosol-active alkali metal and/or alkaline earth metal chlorides.

The plastic-bound pyrotechnic mixture therefore, in accordance with the invention, comprises at least one oxidizer, a carbonate and/or phosphate and/or a mixture of carbonates and/or phosphates from the group of the alkali metals and/or alkaline earth metals, a chlorinated rubber, and a plasticizer. Added thereto, optionally, may be a further binder and/or graphite. The oxidizer ought preferably to be a perchlorate or a mixture of perchlorates from the group of the alkali metals and/or alkaline earth metals. Additionally or alternatively, ammonium perchlorate can be incorporated as an oxidizer. The plasticizer, in contrast, is preferably an organic substance or a substance mixture from the group of the adipates, citrates or phthalates. Alternatively the plasticizer may be an organic phosphoric ester or a phosphoric ester mixture. An additional binder used with preference is an organic titanate or an organic titanate mixture.

Consequently, a plastic-bonded active pyrotechnic composition is proposed which through a variation in its constitution is suitable for generating smokescreens, going as far as smokescreens of low toxicity for practice purposes. The plastic-bound active pyrotechnic composition, like other active smoke compositions, can be employed as well in grenades/munitions, hand grenades or fixed application systems.

The proposed plastic-bound active composition is especially suitable for use as a caseless element, thus allowing, among other things, hand grenades having masses of up to 300 g to be made available, and in comparison to colored smoke application systems, for example, said grenades being more powerful.

Caseless hand grenades based on the proposed plastic-bound pyrotechnic mixtures are equal in terms of geometry, mass, burning characteristics, and burning time, virtually, to the corresponding, likewise plastic-bound, NT active smoke composition application system, whose active smoke component is zinc chloride or complexed zinc chloride (NT-Nebel, see http:/www.brandschutz-passin.de/download/Merkblatt NT Nebelkörper.pdf). This allows realistic training with a reduction in potential toxicity at the same time—in other words, in conjunction with the NT active smoke composition, the plastic-bound active compositions proposed allow the provision of a deployment and practice system for smoke hand grenades that is complete in respect of handling, etc.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.

Claims

1. A plastic-bound pyrotechnic mixture comprising at least one oxidizer, a carbonate and/or phosphate or a mixture of carbonates and/or phosphates from the group of the alkali metals and/or alkaline earth metals, a chlorinated rubber, and a plasticizer.

2. The plastic-bound pyrotechnic mixture of claim 1, wherein all of the components are blended in a ratio to one another such that a neutral smoke in the range pH 5-7,relative to the aerosol is formed.

3. The plastic-bound pyrotechnic mixture of claim 1, wherein a further binder and/or a graphite is incorporated.

4. The plastic-bound pyrotechnic mixture of claim 1, wherein the oxidizer is a perchlorate or a mixture of perchlorates from the group of the alkali metals and/or alkaline earth metals.

5. The plastic-bound pyrotechnic mixture of claim 1, wherein, alternatively or additionally, ammonium perchlorate is incorporated as the oxidizer.

6. The plastic-bound pyrotechnic mixture of claim 1, wherein the plasticizer is an organic substance or substance mixture from the group of the adipates, citrates or phthalates.

7. The plastic-bound pyrotechnic mixture of claim 1, wherein the plasticizer is an organic phosphoric ester or a phosphoric ester mixture.

8. The plastic-bound pyrotechnic mixture of claim 2, wherein the additional binder is an organic titanate or an organic titanate mixture.

9. Caseless and encased smoke grenades or munitions, smoke hand grenades, and fixed smoke application systems, wherein a plastic-bound pyrotechnic mixture according to claim 1 is incorporated therein.