DE3733551A1 - Practice detoxification agent for practicing the decontamination of vehicles and equipment contaminated with chemical warfare substances - Google Patents

Abstract

The disadvantages of the practice detoxification agents known hitherto are their instability in dispersion and the fact that they very rapidly give residues which are difficult to remove. The practice detoxification agent proposed is composed of chalk, surfactant, thickener and water. The procedures of mixing, spray application and washing off enable outstanding simulation but with minimal environmental pollution.

Description

For the decontamination of chemical warfare contaminated Vehicles and equipment are mainly used in the military field u. a. Emulsions of perchlorethylene, calcium hypochlorite, emulsifier and water used. Composition and preparation of such emulsions are z. In TL (Technical Delivery Condition) 6850-0039 described the German Bundeswehr.

For exercise purposes, such emulsions may be environmentally relevant not used.

It therefore results in the task, an exercise detoxification agent to develop, with the one hand, the mixing, spraying and washing process the original emulsion can be simulated, and especially in open terrain, preferably no environmental damage caused.

There are already practice detoxifying agents for practicing decontamination known. In the "Technical Terms of Delivery" (TL 6850-0034) the German Bundeswehr is z. B. describes an aqueous suspension, the talc, titanium dioxide, sodium bisulfate, sodium carbonate and methylcellulose.

This suspension not only has the disadvantage of instability, but There are also problems with the rinsing process after use on. Especially dried residues are difficult or impossible do not remove with cold water. In addition, such Mixture can not be described as "environmentally friendly".

These disadvantages can be avoided by providing a Exercise detoxifying agent for practicing the decontamination of with chemical warfare agents contaminated vehicles and equipment, consisting of  

1.5 to 25.0 percent by weight chalk,
0.1 to 5.0 weight percent surfactant,
0.5 to 2.5 weight percent thickener and
67.5 to 97.9 weight percent water.

In a preferred embodiment, the exercise detoxification agent out

3.0 to 8.0 weight percent chalk,
From 0.5 to 3.0% by weight of surfactant,
0.6 to 1.5 weight percent thickener and
87.5 to 95.9 weight percent water,

wherein the components add up to 100 percent by weight.

The inventive dispersion hardly differs optically from the "real" emulsion. It can do all the work of decontamination can be optimally simulated because the exercise dispersion with respect their handling during storage in different containers, the mixing procedure and the spraying process in the TL 6850-0039 adapted "true" emulsion described.

In addition, this dispersion has very little impact on the environment, because the used components readily biodegradable or without harmful Side effects are or in the case of the used chalk the hyperacidity counteract the soil.

As chalk (calcium carbonate) are all (commercially available) finely ground Types with a particle size <100 microns suitable. Especially good results are obtained with types whose mean particle diameter is about 5 microns.

Below are guideline values for the chemical and physical properties such a commercial product:

CaCO₃ | 99.1% AgO 0.5% Al₂O₃ 0.1% Fe₂O₃ 0.04% SiO₂ 0.08% loss on ignition 43.8% Insoluble in HCl 0.1%

Humidity, max. 0.2% (DIN 53 198) Spec. Wt. 2.7 g / cm³ (DIN 53 193) Special surface 2.5 m² / g (BET / Blaine) tamped volume 80 ml / 100 g (DIN 53 194) tamped density 1.3 g / ml (DIN 53 194) bulk weight 670 g / l (after Böhme) Hardness to Mohs 3 Average particle diameter 5 μm Sieve residue 40 μm 0.1% max. (DIN 53 195) PH value ± 9 (DIN 53 200)

As surfactants are essentially all biodegradable, water-soluble Types with good wetting properties, including mixtures thereof, too use. Examples are: Na-n-dodecylbenzenesulfonate, Na paraffin sulfonates based on 10 paraffins to 18 C-atoms, Na-alkyl ether sulfates based on alcohols with 10 to 18 C atoms and an ethylene oxide content of 1.5 to 4.5 moles / Mol, alkylpolyethylene glycol ethers having 6 to 20 carbon atoms in the branched or straight-chain alkyl group which is saturated or may be unsaturated and 4 to 18 moles of ethylene oxide / mole and Fettsäurepolyethylenglykolester, either by addition of 4 to 18 moles of ethylene oxide with fatty acids, including hydroxy fatty acids, with 8 bis 20 C atoms, which may be saturated or unsaturated or by Esterification of said fatty acids with polyethylene glycols with  average molecular weights of 200 to 1000 in the molar ratio 1: 1 to 2: 1 are produced.

Particularly stable dispersions with very good washing results are with oxethylates of higher alcohols having 8 to 18 carbon atoms and 6 to 14 moles of ethylene oxide as surfactants. Very good Results can be obtained with a Isotridecylalkoholoxethylat with 9 Molen ethylene oxide achieve. - On the use of Alkylphenoloxethylaten as surfactants was omitted for environmental reasons.

Thickeners are all inorganic and organic substances in question, which are able to absorb water, thereby swelling and thus the viscosity of water or an aqueous Phase to increase, cf. Rompps Chemie-Lexikon, 7th edition, Franckhsche Verlagshandlung Stuttgart, page 3792, right column.

Except organic natural thickeners such as agar-agar, tragacanth, Gum arabic, alginates, pactin, starch and gelatin come especially preferably organic modified natural substances in question, such as carboxymethyl cellulose and cellulose ethers, e.g. B. hydroxyethyl cellulose and hydroxypropyl cellulose.

It is also possible to use organic fully synthetic thickeners such as As polyacrylates, polyimines or polyether use, however Attention should be paid to their biodegradability when selecting them become.

Further, inorganic thickening agents are also suitable, such as Bentonites, montmorillonites or zeolites.

The quality of the water is irrelevant. Even high salinity water (eg, seawater) readily provides practice emulsions of the invention. It can, for. B. drinking water of any quality can be used. If necessary, part of the water can be added by adding a corrosion inhibitor (eg, alkanolamide).  

The practice dispersion according to the invention can be prepared so that into the bulk of the water while stirring the thickener slowly interspersed and stirring is continued until a clear, viscous solution is formed (approach A), the surfactant in the residual amount Add water and add the chalk in small portions with stirring and stirring is continued until a homogeneous mass has formed is (approach B). Then, approach B can slowly into the thickened approach A are stirred.

But it is also possible, the dispersion of the invention thereby to prepare a calcium carbonate / surfactant premix in solid Form used. For this, the chalk is in a spray mixer treated with the surfactant (approach D).

To the required similarity of the processing of the exercise dispersion to achieve with the actual decontamination emulsion, The approach D should be pre-mixed with water for practice purposes become (approach E). This approach E can be used in the premix of the thickener be stirred with water.

The invention is further illustrated by the following examples and Comparative Examples:

example 1

This gives a stable, slightly viscous white dispersion, both can be applied to surfaces by brushing as well as spraying, with very good adhesive properties even on vertical surfaces. you is particularly characterized by the fact that even after 24 hours Stand still no particulate matter has separated and after application, even after drying, effortlessly with cold water through Cumshot can be removed again. If you use instead of Drinking water of the North Sea, one receives a dispersion with comparable Properties.

example 2

The procedure is as in Example 1, but stores the approaches A and B 8 days separated at room temperature in closed vessels. After that, as described in Example 1, batch B and A combined. This gives a dispersion with comparable properties of the Example 1 described.

Example 3

This dispersion behaves essentially as in Example 1 described. A slightly worse Wasserabspülbarkeit will here consciously accepted; the significantly lower amount of surfactant means at the same time lower environmental impact, especially when used in the open Terrain. Is used instead of the Hydroxiethylcellulose a Carboximethylcellulose, gives a comparable dispersion.

example 4

The procedure is as in Example 1, but instead of Isotridecylalkoholethoxylates a Na-fatty alcohol ether sulfate based on a native C _12-14 alcohol with 2.5 moles of ethylene oxide per mole of alcohol used. This gives a dispersion with comparable properties.

example 5

The procedure is as in Example 1, but instead of Isotridecylalkoholethoxylates following surfactant mixture used:  

Na n-dodecylbenzenesulfonate | (61.8%) Na lauryl ether sulfate (2.5 EO) (16.6%) C _12-14 fatty alcohol ethoxylate (10 EO) (16.6%) coconut fatty acid diethanolamide (5.0%)

This gives a dispersion with comparable properties.

Example 6 (comparative experiment)

(previous practice emulsion of the DBW)

This gives a greyish-white unstable dispersion, which already after short standing (30 minutes) distinct settling of the suspended Shows solid particles so that they are on before applying Surfaces must be homogenized again. Particularly disadvantageous is that an effortless spraying with water only immediately after application is possible; a dried or dry film of this Dispersion is virtually impossible to remove with cold water. In addition, the solids used (TiO₂, talc, sodium carbonate and sodium hydrogen sulfate) are not as environmentally friendly as those of the exercise detoxifying agent according to the invention.

Claims (2)

1. Exercise detoxification agent for practicing the decontamination of vehicles and equipment contaminated with chemical warfare agents, consisting of:
1.5 to 25.0 percent by weight chalk,
0.1 to 5.0 weight percent surfactant,
0.5 to 2.5 weight percent thickener,
67.5 to 97.9 weight percent water and
optionally minor additives, such as corrosion inhibitors,
wherein the components add up to 100 percent by weight. 2. exercise detoxifying agent according to claim 1, consisting of:
3.0 to 8.0 weight percent chalk,
From 0.5 to 3.0% by weight of surfactant,
0.6 to 1.5 weight percent thickener,
87.5 to 95.9 weight percent water and
optionally minor additives, such as corrosion inhibitors,
wherein the components add up to 100 percent by weight.