IMPROVEMENTS IN OR RELATING TO CASELESS PROPELLENT CHARGES

A lay compressed loads, consisting of slow burning or explosion proof instrument, does not produces detonation, as nitrocellulose, polyvinyl nitrate, nitroguanidine, nitrourea the, etc, or mixtures thereof, preferably to charge industrial use, for example in working machines insertion of bolts, impact tools, control elements, fast switches, andc."

Also important are the advantages that of [...] such powder charges compressed due to the absence of the usual cartridge, is encountered however the significant drawback that the surface of the pressed bodies is not protected and remains responsive, which may yield their ignition flammability easy due to the explosives used for their manufacture or by unintentional manipulation. This cannot therefore storing and using such loads that with particular precautions.

Furthermore, the exposed surface of body absorbs explosive tablets ^ as a result of the nature of the used and [...] of the structure substantially [...] moisture, for example water or other liquids, and soils, such as grease, oil or the dross.

In addition to safety precautions thereby treat the body is to be particularly careful for avoiding the drawbacks often harsh handling practice.

The aim of the invention is to avoid the disadvantages indicated above. This is achieved by covering the pressed bodies of a protective layer, preferably thin, which prevents an ignition and/or nuisance combustion and the soiling or moisture absorption.

According to a preferred embodiment of the invention, the protective layer is produced on the surface of the tablets by denitration body of the surface, that is say by reducing the nitro groups or nitrate present in the surface. Ge result is obtained in a simple manner by treating the pressed bodies in a bath of appropriate chemicals * .such as sulphide or [...] etc, and by washing out the cleavage products.

In addition to this surface treatment, or in its place, can be used in an embodiment of the invention, for

bad original form the layer [...]. es synthetic resins, as polyurethanes, [...], etc, is soluble resin, for example polyvinyl acetate or copolymers, polyacrylates, and dispersions base polybutadienes, polyvinyl acetate or polyacrylates. Alternatively, can be used for forming the protective layer other products such as methylcellulose, glycolates the cellulose and the like, ,

The application of the protective layer may be achieved according to the material used dip, [...] or precipitation from a solution,. For the soaking and 1' [...] bone can use polyurethane lacquers, which can be used to the prepolymerized state with subsequent crosslinking that as lacques [...], and also aromatic ethers [...][...], mixed polymers of polyethylene and polyvinyl acetate, polyacrylic esters, of dispersions of polyvinyl acetate, of mixed polymerizates [...] at polyacrylates. For the precipitation are advantageously used, e.g., glycolates of [...]

When there is an ignition charge or when such a load is provided, the protective layer may cover and optionally be used to secure it. Because the method of the present invention avoid any modifications in the porous structure of the compressed bodies that the protective layer can therefore remain very thin, the sensitivity of the ignition of the compressed body is not compromised, but the danger of handling is reduced to a tolerable size. Furthermore, contamination is avoided and large is improved resistance to friction and mechanical loads, without producing significant residue*

Is produced from a fibrous nitrocellulose, moistened with water, of a title of 12.6 ¢ nitrogen, mixed with 3p of[...] and 0.5 $of [...], and in a hydraulic press with a suitable matrix tablets of 6 mm in diameter and 5 mm thickness d *" It bears on one of the surfaces a hollow, inclined 2 mm depth d^{8 a diameter of} 4 m. to the upper part. The pellets have a smooth surface and mechanical strength so that they do not disrupt during its

BAD ORIGINAL bV [...][...]/ [...] of a normal handling " © The structure [...] unreacted results in the droplets of liquids are still be easily absorbed. Es tablets is dried prior to subsequent processing. A in the hollow 5 mg of a load of wet [...], is then dried the tablets to removal of moisture. They are then passes into a bath with:

20,4 parts of a polyglycol having a molecular weight fi® 1200,6 parts tolylene diisocyanate

3 parts do [...] ds phthalate is

70 parts ds d © methylene chloride.

On the surface it remains aae film^{s M} "i" do place from which the solvent evaporates fast present *" member. Subsequent heating consolidates the coating and thin layer is obtained and secured ©, which protects all sides of the body of powder does not and night to the sensitivity d^{9 ~ [...] Al} tablets. When firing, is observed for any-hensive * residues.