EP0446085B1 - Process for fabricating high temperature resistant fragmentable propellant charges, the charges thus obtained and their constituent powders - Google Patents

Process for fabricating high temperature resistant fragmentable propellant charges, the charges thus obtained and their constituent powders Download PDF

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Publication number
EP0446085B1
EP0446085B1 EP19910400319 EP91400319A EP0446085B1 EP 0446085 B1 EP0446085 B1 EP 0446085B1 EP 19910400319 EP19910400319 EP 19910400319 EP 91400319 A EP91400319 A EP 91400319A EP 0446085 B1 EP0446085 B1 EP 0446085B1
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Prior art keywords
powder
dinitropolystyrene
grains
weight
solvent
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EP19910400319
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German (de)
French (fr)
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EP0446085A1 (en
Inventor
Jacques Boileau
Louis Leneveu
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EURENCO FRANCE S.A.
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Societe Nationale des Poudres et Explosifs
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    • C—CHEMISTRY; METALLURGY
    • C06—EXPLOSIVES; MATCHES
    • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
    • C06B45/00—Compositions or products which are defined by structure or arrangement of component of product
    • C06B45/02—Compositions or products which are defined by structure or arrangement of component of product comprising particles of diverse size or shape
    • C—CHEMISTRY; METALLURGY
    • C06—EXPLOSIVES; MATCHES
    • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
    • C06B21/00—Apparatus or methods for working-up explosives, e.g. forming, cutting, drying
    • C06B21/0033—Shaping the mixture
    • C06B21/0041—Shaping the mixture by compression
    • C—CHEMISTRY; METALLURGY
    • C06—EXPLOSIVES; MATCHES
    • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
    • C06B21/00—Apparatus or methods for working-up explosives, e.g. forming, cutting, drying
    • C06B21/0083—Treatment of solid structures, e.g. for coating or impregnating with a modifier
    • C—CHEMISTRY; METALLURGY
    • C06—EXPLOSIVES; MATCHES
    • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
    • C06B45/00—Compositions or products which are defined by structure or arrangement of component of product
    • C06B45/18—Compositions or products which are defined by structure or arrangement of component of product comprising a coated component

Definitions

  • the present invention relates to the field of propellant charges for small and medium caliber tube weapons. More specifically, the invention relates to a process for the production of temperature-resistant fragmentable propellant charges as well as the powders and charges obtained by this method.
  • a fragmentable charge is obtained by compression of grains of propellant powder.
  • This compression is generally carried out on grains of powder impregnated with a nitrocellulose plasticizer or with a crosslinkable binder as described for example in US Patents 3,655,836 or FR 2,374,278.
  • thermoplastic binder A particularly interesting energetic thermoplastic binder is found to be polyvinyl nitrate.
  • a first possibility described for example in French patent 2 411 817, consists in carrying out the hot compression of a mixture of grains of powder and grains of binder composition based on polyvinyl nitrate.
  • a second possibility described for example in French patent 2,436,766, consists in carrying out the hot compression of grains of powder coated with a film based on polyvinyl nitrate.
  • the powder grains are coated by a coating operation during which a powder solution of polyvinyl nitrate in a volatile solvent is sprayed onto the powder grains.
  • Fragmentable charges obtained from propellant powder compressed in the presence of polyvinyl nitrate are effectively energetic and fragment very well at the time of firing but they have a limit of use linked to the poor temperature resistance of polyvinyl nitrate which softens from 70 ° C.
  • many current munitions have specifications for use which require good mechanical strength at least up to 100 ° C.
  • the object of the invention is precisely to propose such fragmentable propellant charges as well as a process for manufacturing these charges.
  • the invention therefore relates to a method for manufacturing fragmentable propellant charges for ammunition without a cartridge from propellant powder in grains, characterized in that in a first step, said grains of powder first undergo a coating operation during which a mixture containing at least one dinitropolystyrene, a stabilizer and a derivative of polvinyl alcohol chosen from the group consisting of polyvinyl nitrate and polyvinyl acetate is sprayed onto the powder grains, said mixture being in solution in a medium solvent, and in that, after evaporation of said solvent medium, in a second step, the powder grains thus obtained are compressed at a temperature between 100 ° C and 140 ° C.
  • the weight ratio between the dinitropolystyrene and the dinitropolystyrene unit-derivative of polyvinyl alcohol is between 25% and 75%.
  • part of the derivative of polyvinyl alcohol is replaced by cellulose acetate.
  • said solvent medium comprises at least one solvent for dinitropolystyrene chosen from the group consisting of cyclohexanone, tetraalkylureas such as tetramethylurea, nitrobenzene, butyrolactone and tetramethylene sulfone.
  • the invention also relates to the fragmentable propellant charges for ammunition without a cartridge obtained by the method according to the invention.
  • the invention relates in particular to the loadings in which the propellant powder in grains is a single nitrocellulose base powder.
  • the invention also relates to the propellant powder grains obtained at the end of the first step of the process according to the invention which are characterized in that said grains are coated with a film of a mixture containing at least one dinitropolystyrene, a stabilizer and a derivative of polyvinyl alcohol chosen from the group consisting of polyvinyl nitrate and acetate polyvinyl.
  • the method according to the invention therefore consists in a first step of coating grains of propellant powder with a film of an energetic thermoplastic material and in a second step of hot pressing the grains of powder thus coated.
  • propellant powder it is possible to use in the context of the present invention most of the propellant powders known to those skilled in the art. It is thus possible in particular to use powders with a simple nitrocellulose base or so-called “composite" powders constituted mainly by a nitramine such as hexogen or octogen and by an organic binder such as a polyurethane, a polyester, an acetobutyrate. cellulose alone or in admixture with nitrocellulose and triethyl citrate acetate.
  • composite powders constituted mainly by a nitramine such as hexogen or octogen and by an organic binder such as a polyurethane, a polyester, an acetobutyrate. cellulose alone or in admixture with nitrocellulose and triethyl citrate acetate.
  • powders containing nitroglycerin or more generally a nitrated oil such as so-called “double base” powders constituted by a mixture of nitrocellulose and nitroglycerine or powders called “multibase” constituted by nitrocellulose, nitroglycerin and one or more nitro energetic compounds such as nitroguanidine, hexogen, octogen, pentrite, dinitroglycolurile, etc ...
  • double base powders constituted by a mixture of nitrocellulose and nitroglycerine or powders called “multibase” constituted by nitrocellulose, nitroglycerin and one or more nitro energetic compounds such as nitroguanidine, hexogen, octogen, pentrite, dinitroglycolurile, etc ...
  • the Applicant recommends not using powders with a nitroglycerin or nitrated oil content greater than 25% by weight. For most shipments intended for small and medium caliber weapons, single nitrocellulose-based powders will usually be used
  • the geometry of the powder grain will depend on the dimensions and properties desired for the fragmentable load.
  • the powder grains, smoothed or unsmoothed, are therefore coated with a film of an energetic thermoplastic material.
  • this material is typically constituted by the mixture of at least one dinitropolystyrene, a stabilizer, and a derivative of polyvinyl alcohol chosen from the group consisting of polyvinyl nitrate and l polyvinyl acetate.
  • the weight ratio between the dinitropolystyrene and the assembly constituted by the dinitropolystyrene and the derivative (s) of polyvinyl alcohol must be between 25% and 75%.
  • Dinitropolystyrene is an organic polymer with the formula in which the symbols C, H, O, N represent carbon, hydrogen, oxygen and nitrogen respectively and n represents an integer.
  • dinitropolystyrenes of different molecular weights can be used, but those whose softening temperature is higher than 260 ° C. are preferred.
  • Dinitropolystyrene is advantageously obtained by nitration of polystyrene according to the techniques described, for example, in the following works: Mémorial des Poudres, volume 35, 1953, pages 41 to 50 (Boniau, Pujo, Lang), Encyclopedia of Explosives and Relative Items, volume 8, 1978, pages 143-144, or even in US patent 3,715,323.
  • stabilizer of the mixture conventional stabilizers of nitro compounds such as diphenylamine or 2-nitro-diphenylamine can be used, however the preferred stabilizer is 2-nitro-diphenylamine.
  • This stabilizer will be present in the mixture at a rate of approximately 2% by weight of the total weight of the dinitropolystyrene assembly and derivatives of polyvinyl alcohol.
  • the mixture coating the powder grains therefore contains at least one derivative of polyvinyl alcohol chosen from the group consisting of polyvinyl nitrate and polyvinyl acetate. It can simultaneously contain these two derivatives.
  • part of the derivatives of polyvinyl alcohol can be replaced by cellulose acetate but, and this is an important condition for implementing the invention, cellulose acetate cannot completely replace polyvinyl alcohol derivatives.
  • the derivatives of polyvinyl alcohol, polyvinyl nitrate and / or polyvinyl acetate must represent at least one third by weight of the total weight of the cellulose acetate + derivatives of polyvinyl alcohol.
  • the solvent medium comprises at least one dinitropolystyrene solvent chosen from the group consisting of cyclohexanone, tetramethylurea, nitrobenzene, butyrolactone and tetramethylene sulfone still known under the trade name SULFOLANE®, so as to ensure good dissolution of the dinitropolystyrene .
  • the preferred solvents for dinitropolystyrene in the context of the invention are cyclohexanone, tetramethylurea and tetramethylene sulfone.
  • said solvent is used in admixture with an auxiliary solvent which is a good solvent for derivatives of polyvinyl alcohol and cellulose acetate.
  • Acetone is a preferred auxiliary solvent in the context of the present invention.
  • the amount of coating material deposited on the powder grains should be about two percent of the weight of the powder.
  • This deposition is carried out by spraying the solution of coating material onto the powder grains, for example in a rotating bezel as for a conventional smoothing operation. After spraying the solution, the solvent medium is removed by air drying, optionally supplemented by drying in an oven, at atmospheric pressure or under vacuum.
  • the powder grains thus coated are then compressed to the shape and dimensions of the desired fragmentable load.
  • This compression is advantageously carried out at a temperature between 100 ° C and 140 ° C.
  • a pressure close to 100 bars, or 10 replenish Pa, is generally sufficient for the usual loads intended for small and medium-caliber weapons.
  • This second step of the process can take place either immediately after the first step or later in time as explained later in the description.
  • the invention also relates to the fragmentable propellant charges thus obtained.
  • load is meant in the sense of the present application either the propellant load in its entirety if it consists of a single element, or an element constituting the load if the latter consists of a plurality of elements.
  • loads obtained by agglomeration of powder grains coated according to the invention have good mechanical strength when cold and still retain a certain mechanical strength at 100 ° C., in contrast to the loads obtained by agglomeration of powder grains coated only with polyvinyl nitrate . Furthermore, the loads according to the invention have ballistic properties comparable to those of traditional loads and in particular exhibit, on combustion, a perfectly correct fragmentation.
  • the propellant charges according to the invention obtained from propellant powder with a simple nitrocellulose base will advantageously be used, this powder being the most common and the most common today. economic.
  • the invention also relates to the powders constituting the loads according to the invention. More specifically, the invention relates to the propellant powder grains obtained at the end of the first step of the process according to the invention after evaporation of the solvent medium. These powder grains are coated with a film of a mixture containing at least one dinitropolystyrene, a stabilizer and a derivative of polyvinyl alcohol chosen from the group consisting of polyvinyl nitrate and polyvinyl acetate.
  • the invention particularly relates to the coated grains obtained from a single-base nitrocellulose powder. Such powder grains keep well over time and can be easily transported. They thus make it possible to dissociate, in time and even in space, the two stages of the method according to the invention, according to the needs.
  • the powder used is a conventional powder based on nitrocellulose in cylindrical grains having a central hole, web (thickness to be burned) 0.25 mm. At the start, the powder is not smoothed and not graphitized and its potential is 4,034 joules / g, ie 965 cal / g.
  • the powder is coated as follows: 5 kg of powder, 2.5 g of graphite are introduced into a bezel heated to 25 ° C. and a coating solution is sprayed, the overall composition of which is the next one : - polyvinyl nitrate 2% of the weight of the powder - acetone 20% of the weight of the powder - ethanol 4% of the weight of the powder - 2-nitro diphenylamine 0.04% by weight of the powder
  • the temperature of the coating solution is 60 ° C, the temperature of the pan being 25 ° C.
  • Solid fragmentable cylindrical blocks 22 mm high and 12.6 mm in diameter are thus obtained, having the following characteristics: potential 3,840 joules / g or 918 cal / g aspect correct crush resistance + 21 ° C: 0.60 kN / cm2 + 100 ° C: mechanical strength too weak to be able to be measured.
  • Fragmentable charges according to the invention were made from propellant powder in grains coated with a mixture of polyvinyl nitrate (NPV) and dinitropolystyrene (DNPS) in the presence of 2-nitro diphenylamine (2-NDPA) as a stabilizer.
  • NPV polyvinyl nitrate
  • DNPS dinitropolystyrene
  • 2-NDPA 2-nitro diphenylamine
  • Example 2 The powder used was the same as that of Example 1 and the coating was carried out as described in Example 1 with coating solutions whose overall compositions were as follows: EX 2 EX 3 EX 4 EX 5 EX 6 NPV 1% 0.5% 1% 1.2% 1.5% DNPS 1% 1.5% 1% 0.8% 0.5% cyclohexanone 18% 18% 7% 5.6% 4% acetone 0% 0% 15% 18% 18% 2-NDPA 0.04% 0.04% 0.04% 0.04% 0.04% 0.04% 0.04% 0.04% 0.04% 0.04% 0.04% 0.04% 0.04% 0.04% 0.04% 0.04% 0.04% 0.04% 0.04%
  • the percentages are expressed by weight relative to the total weight of the powder.
  • the dinitropolystyrene used had a nitrogen content of 14.81%, an average molecular weight of 500,000 and a softening point above 260 ° C. It is this dinitropolystyrene which was used in all the examples.
  • the compression of the coated grains was carried out in a similar manner to that described in Example 1, the compression temperature being 130 ° C.
  • the residual percentage of cyclohexanone is expressed by weight relative to the total weight of the load.
  • a fragmentable charge according to the invention was made from propellant powder in grains coated with a mixture of polyvinyl acetate (AcPV) and dinitropolystyrene (DNPS) in the presence of 2-nitro diphenylamine (2-NDPA) as stabilizer.
  • AcPV polyvinyl acetate
  • DNPS dinitropolystyrene
  • 2-NDPA 2-nitro diphenylamine
  • the powder used is the same as that of Example 1.
  • the coating is carried out as follows: into a bezel heated to 25 ° C. 5 kg of powder, 2.5 g of graphite are introduced and sprayed in four times a coating solution whose overall composition is as follows: - AcPV 1% of the weight of the powder - DNPS 1% of the weight of the powder - cyclohexanone 10% of the weight of the powder - acetone 10% of the weight of the powder - 2-NDPA 0.04% by weight of the powder
  • the temperature of the coating solution was 60 ° C. After spraying, the pan was left to rotate for 5 minutes with the doors open, then the powder was put to dry in an oven for 16 hours at 60 ° C. The coated powder was then introduced into a mold heated to 130 ° C., the powder was left in the mold for 5 minutes and was compressed for 1 minute at 107 Pa, ie 100 bars. Solid cylindrical fragmentable blocks 22 mm high and 12.6 mm in diameter were thus obtained, having the following characteristics: aspect correct potential 3,770 joules / g or 902 cal / g crush resistance + 21 ° C: 1.01 kN / cm2 + 100 ° C: 0.86 kN / cm2
  • a fragmentable charge according to the invention was made from propellant powder in grains coated with a mixture of dinitropolystyrene (DNPS), polyvinyl nitrate (NPV) and polyvinyl acetate (AcPV) in the presence of 2-nitro diphenylamine (2-NDPA) as a stabilizer.
  • DNPS dinitropolystyrene
  • NPV polyvinyl nitrate
  • AcPV polyvinyl acetate
  • 2-NDPA 2-nitro diphenylamine
  • Example 7 The procedure was as described in Example 7 with a coating solution whose overall composition was as follows: - DNPS 0.67% of the weight of the powder - NPV 0.67% of the weight of the powder - AcPV 0.67% of the weight of the powder - 2-NDPA 0.04% by weight of the powder - cyclohexanone 10% of the weight of the powder - acetone 10% of the weight of the powder
  • Fragmentable blocks were thus obtained having the following characteristics: aspect correct potential 3,860 joules / g or 924 cal / g crush resistance + 21 ° C: 0.66 kN / cm2 + 100 ° C: 0.44 kN / cm2
  • Examples 7 and 8 demonstrate that polyvinyl acetate can replace polyvinyl nitrate in all proportions in the context of the present invention.
  • a fragmentable charge according to the invention was made from propellant powder in grains coated with a mixture of dinitropolystyrene (DNPS), polyvinyl nitrate (NPV) and cellulose acetate (AcCell) in the presence of 2-nitro diphenylamine (2-NDPA) as a stabilizer.
  • DNPS dinitropolystyrene
  • NPV polyvinyl nitrate
  • AcCell cellulose acetate
  • 2-NDPA 2-nitro diphenylamine
  • Example 7 We proceeded as described in Example 7 with a solution coating whose overall composition was as follows: - DNPS 0.67% of the weight of the powder - NPV 0.67% of the weight of the powder - AcCell 0.67% of the weight of the powder - cyclohexanone 10% of the weight of the powder - acetone 10% of the weight of the powder - 2-NDPA 0.04% by weight of the powder
  • Fragmentable blocks were thus obtained having the following characteristics: aspect correct potential 3,854 joules / g or 922 cal / g crush resistance + 21 ° C: 0.24 kN / cm2 + 100 ° C: 0.23 kN / cm2
  • Example 7 The procedure was as described in Example 7 with a coating solution whose overall composition was as follows: - DNPS 1% of the weight of the powder - AcCell 1% of the weight of the podure - 2-NDPA 0.04% by weight of the powder - cyclohexanone 10% of the weight of the powder - acetone 10% of the weight of the powder
  • a fragmentable charge according to the invention was made from propellant powder in grains coated with a mixture of dinitropolystyrene (DNPS) and polyvinyl nitrate (NPV) in the presence of 2-nitro diphenylamine (2-NDPA) as stabilizer and using nitrobenzene as solvent.
  • DNPS dinitropolystyrene
  • NPV polyvinyl nitrate
  • Example 7 The procedure was as described in Example 7 with a coating solution whose overall composition was as follows: - DNPS 1% of the weight of the powder - NPV 1% of the weight of the powder - 2-NDPA 0.04% by weight of the powder - nitrobenzene 15% of the weight of the powder
  • Fragmentable blocks were thus obtained having the following characteristics: aspect correct potential 3,460 joules / g or 828 cal / g crush resistance + 21 ° C: 0.49 kN / cm2 + 100 ° C: 0.23 kN / cm2
  • a fragmentable charge according to the invention was made from propellant powder in grains coated with a mixture of dinitropolystyrene (DNPS) and polyvinyl nitrate (NPV) in the presence of 2-nitro diphenylamine (2-NDPA) as stabilizer and using tetramethylurea as a solvent.
  • DNPS dinitropolystyrene
  • NPV polyvinyl nitrate
  • Example 7 The procedure was as described in Example 7 with a coating solution whose overall composition was as follows: - DNPS 1% of the weight of the powder - NPV 1% of the weight of the powder - 2-NDPA 0.04% by weight of the powder - tetramethylurea 15% of the weight of the powder
  • Fragmentable blocks were thus obtained having the following characteristics: aspect correct potential 3,680 joules / g or 880 cal / g crush resistance + 21 ° C: 1.89 kN / cm2 + 100 ° C: 1.04 kN / cm2
  • a fragmentable charge according to the invention was made from propellant powder in grains coated with a mixture of dinitropolystyrene (DNPS) and polyvinyl nitrate (NPV) in the presence of 2-nitro diphenylamine (2-NDPA) as stabilizer and using butyrolactone as solvent.
  • DNPS dinitropolystyrene
  • NPV polyvinyl nitrate
  • Example 7 The procedure was as described in Example 7 with a coating solution whose overall composition was as follows: - DNPS 1% of the weight of the powder - NPV 1% of the weight of the powder - 2-NDPA 0.04% by weight of the powder - butyrolactone 15% of the weight of the powder
  • Fragmentable blocks were thus obtained having the following characteristics: aspect correct potential 3,106 joules / g or 743 cal / g crush resistance + 21 ° C: 0.85 kN / cm2 + 100 ° C: 0.29 kN / cm2
  • a fragmentable charge according to the invention was made from propellant powder in grains coated with a mixture of dinitropolystyrene (DNPS) and polyvinyl nitrate (NPV) in the presence of 2-nitro diphenylamine (2-NDPA) as stabilizer and using tetramethylene sulfone as solvent.
  • DNPS dinitropolystyrene
  • NPV polyvinyl nitrate
  • Example 7 The procedure was as described in Example 7 with a coating solution whose overall composition was as follows: - DNPS 1% of the weight of the powder - NPV 1% of the weight of the powder - acetone 12% of the weight of the powder - tetramethylene sulfone 6% of the weight of the powder - 2-NDPA 0.04% by weight of the powder
  • Fragmentable blocks were thus obtained having the following characteristics: aspect correct potential 3,712 joules / g or 886 cal / g crush resistance + 21 ° C: 1.1 kN / cm2 + 100 ° C: 0.6 kN / cm2
  • a fragmentable charge was made according to the invention using a composite powder, the composition of which was as follows: - hexogen (coated with 2% by weight of dioctyl phthalate) 80 parts by weight - centrality 0.4 parts by weight - nitrocellulose (nitrogen content 11.8%) 4 parts by weight - cellulose acetate butyrate 9.6 parts by weight - ATEC 6 parts by weight
  • ATEC designates triethyl citrate acetate of formula:
  • the potential of this powder was 3,595 joules / g or 860 cal / g.
  • a coating solution whose overall composition was as follows: - polyvinyl nitrate 0.67% of the weight of the powder - polyvinyl acetate 0.67% of the weight of the powder - dinitropolystyrene 0.67% of the weight of the powder - cyclohexanone 10% of the weight of the powder - acetone 10% of the weight of the powder
  • Fragmentable blocks were thus obtained having the following characteristics: aspect correct potential 3,574 joules / g or 855 cal / g crush resistance + 21 ° C: 0.89 kN / cm2 + 100 ° C: 0.59 kN / cm2

Description

La présente invention se rapporte au domaine des chargements propulsifs pour armes à tube de petit et moyen calibre. Plus précisément l'invention concerne un procédé de fabrication de chargements propulsifs fragmentables résistant à la température ainsi que les poudres et chargements obtenus par ce procédé.The present invention relates to the field of propellant charges for small and medium caliber tube weapons. More specifically, the invention relates to a process for the production of temperature-resistant fragmentable propellant charges as well as the powders and charges obtained by this method.

Dans le but de disposer du maximum d'énergie propulsive dans les munitions pour armes à tube de petit et moyen calibre, on cherche à augmenter la densité du chargement en l'agglomérant. Au moment de la combustion un tel chargement aggloméré doit, sous l'effet de la montée en pression, se fragmenter pour redonner les grains constitutifs de la poudre de départ et brûler comme un chargement en vrac. Les chargements agglomérés se révèlent particulièrement intéressants dans le cas où, toujours pour disposer du maximum d'énergie, on cherche en plus à s'affranchir de la douille pour obtenir des munitions dites "télescopées" comme décrites par exemple dans le brevet français 2 357 854.In order to have the maximum propulsive energy in ammunition for small and medium caliber tube weapons, we seek to increase the density of the load by agglomerating it. At the time of combustion, such an agglomerated load must, under the effect of the pressure increase, fragment to give back the grains constituting the starting powder and burn as a bulk load. The agglomerated loadings prove to be particularly interesting in the case where, still in order to have the maximum of energy, one seeks in addition to dispense with the socket to obtain so-called "telescoped" ammunition as described for example in French patent 2,357 854.

Fondamentalement un chargement fragmentable est obtenu par compression de grains de poudre propulsive.Basically a fragmentable charge is obtained by compression of grains of propellant powder.

Cette compression est en général effectuée sur des grains de poudre imprégnés par un plastifiant de la nitrocellulose ou par un liant réticulable comme décrit par exemple dans les brevets US 3 655 836 ou FR 2 374 278.This compression is generally carried out on grains of powder impregnated with a nitrocellulose plasticizer or with a crosslinkable binder as described for example in US Patents 3,655,836 or FR 2,374,278.

Néanmoins pour des questions de faisabilité industrielle on préfère éviter les plastifiants ou les liants liquides et par ailleurs, dans le but d'accroître l'énergie du chargement, on cherche à utiliser des liants énergétiques. Ce double impératif a conduit l'homme de métier à s'orienter vers une compression à chaud des grains de poudre en présence d'un liant thermoplastique énergétique. Un liant thermoplastique énergétique particulièrement intéressant se trouve être le nitrate de polyvinyle. Il existe deux possibilités d'utilisation de ce liant en vue de la fabrication de chargements propulsifs agglomérés fragmentables. Une première possibilité, décrite par exemple dans le brevet français 2 411 817, consiste à effectuer à chaud la compression d'un mélange de grains de poudre et de grains de composition liante à base de nitrate de polyvinyle. Une seconde possibilité, décrite par exemple dans le brevet français 2 436 766, consiste à effectuer à chaud la compression de grains de poudre enrobés par une pellicule à base de nitrate de polyvinyle.However, for industrial feasibility reasons, it is preferable to avoid plasticizers or liquid binders and, moreover, with the aim of increasing the loading energy, we seek to use energy binders. This double imperative led the skilled person to move towards hot compression of the grains of powder in the presence of an energetic thermoplastic binder. A particularly interesting energetic thermoplastic binder is found to be polyvinyl nitrate. There are two possibilities of using this binder for the manufacture of fragmentable agglomerated propellant charges. A first possibility, described for example in French patent 2 411 817, consists in carrying out the hot compression of a mixture of grains of powder and grains of binder composition based on polyvinyl nitrate. A second possibility, described for example in French patent 2,436,766, consists in carrying out the hot compression of grains of powder coated with a film based on polyvinyl nitrate.

L'enrobage des grains de poudre se fait par une opération d'enrobage au cours de laquelle on pulvérise sur les grains de poudre une solution de nitrate de polyvinyle dans un solvant volatil.The powder grains are coated by a coating operation during which a powder solution of polyvinyl nitrate in a volatile solvent is sprayed onto the powder grains.

Les chargements fragmentables obtenus à partir de poudre propulsive comprimée en présence de nitrate de polyvinyle sont effectivement énergétiques et se fragmentent très bien au moment du tir mais ils présentent une limite d'utilisation liée à la mauvaise tenue en température du nitrate de polyvinyle qui se ramollit à partir de 70°C. Or de nombreuses munitions actuelles ont des spécifications d'utilisation qui exigent une bonne tenue mécanique au moins jusqu'à 100°C.Fragmentable charges obtained from propellant powder compressed in the presence of polyvinyl nitrate are effectively energetic and fragment very well at the time of firing but they have a limit of use linked to the poor temperature resistance of polyvinyl nitrate which softens from 70 ° C. However, many current munitions have specifications for use which require good mechanical strength at least up to 100 ° C.

Il existe donc à l'heure actuelle un réel besoin en chargements propulsifs fragmentables qui présentent les mêmes propriétés balistiques que les chargements connus obtenus à partir de poudre propulsive en grains et de nitrate de polyvinyle mais qui soient plus résistants en température.There is therefore currently a real need for fragmentable propellant charges which have the same ballistic properties as the known charges obtained from propellant powder in grains and polyvinyl nitrate but which are more resistant in temperature.

Le but de l'invention est précisément de proposer de tels chargements propulsifs fragmentables ainsi qu'un procédé de fabrication de ces chargements.The object of the invention is precisely to propose such fragmentable propellant charges as well as a process for manufacturing these charges.

L'invention concerne donc un procédé de fabrication de chargements propulsifs fragmentables pour munitions sans douille à partir de poudre propulsive en grains, caractérisé en ce que dans une première étape lesdits grains de poudre subissent d'abord une opération d'enrobage au cours de laquelle on pulvérise sur les grains de poudre un mélange contenant au moins un dinitropolystyrène, un stabilisant et un dérivé de l'alcool polvinylique choisi dans le groupe constitué par le nitrate de polyvinyle et l'acétate de polyvinyle, ledit mélange étant en solution dans un milieu solvant, et en ce que, après évaporation dudit milieu solvant, dans une seconde étape on comprime les grains de poudre ainsi obtenus à une température comprise entre 100°C et 140°C.The invention therefore relates to a method for manufacturing fragmentable propellant charges for ammunition without a cartridge from propellant powder in grains, characterized in that in a first step, said grains of powder first undergo a coating operation during which a mixture containing at least one dinitropolystyrene, a stabilizer and a derivative of polvinyl alcohol chosen from the group consisting of polyvinyl nitrate and polyvinyl acetate is sprayed onto the powder grains, said mixture being in solution in a medium solvent, and in that, after evaporation of said solvent medium, in a second step, the powder grains thus obtained are compressed at a temperature between 100 ° C and 140 ° C.

Selon une réalisation préférée de l'invention le rapport pondéral entre le dinitropolystyrène et l'ensemble dinitropolystyrène-dérivé de l'alcool polyvinylique est compris entre 25 % et 75 %.According to a preferred embodiment of the invention, the weight ratio between the dinitropolystyrene and the dinitropolystyrene unit-derivative of polyvinyl alcohol is between 25% and 75%.

Selon une première variante, une partie du dérivé de l'alcool polyvinylique est remplacée par de l'acétate de cellulose.According to a first variant, part of the derivative of polyvinyl alcohol is replaced by cellulose acetate.

Selon une seconde variante, ledit milieu solvant comprend au moins un solvant du dinitropolystyrène choisi dans le groupe constitué par la cyclohexanone, les tétraalkylurées comme la tétraméthylurée, le nitrobenzène, la butyrolactone et la tétraméthylène sulfone.According to a second variant, said solvent medium comprises at least one solvent for dinitropolystyrene chosen from the group consisting of cyclohexanone, tetraalkylureas such as tetramethylurea, nitrobenzene, butyrolactone and tetramethylene sulfone.

L'invention concerne également les chargements propulsifs fragmentables pour munitions sans douille obtenus par le procédé selon l'invention.The invention also relates to the fragmentable propellant charges for ammunition without a cartridge obtained by the method according to the invention.

L'invention concerne en particulier les chargements dans lesquels la poudre propulsive en grains est une poudre à simple base à la nitrocellulose.The invention relates in particular to the loadings in which the propellant powder in grains is a single nitrocellulose base powder.

Enfin l'invention concerne également les grains de poudre propulsive obtenus à l'issue de la première étape du procédé selon l'invention qui sont caractérisés en ce que lesdits grains sont enrobés par une pellicule d'un mélange contenant au moins un dinitropolystyrène, un stabilisant et un dérivé de l'alcool polyvinylique choisi dans le groupe constitué par le nitrate de polyvinyle et l'acétate de polyvinyle.Finally, the invention also relates to the propellant powder grains obtained at the end of the first step of the process according to the invention which are characterized in that said grains are coated with a film of a mixture containing at least one dinitropolystyrene, a stabilizer and a derivative of polyvinyl alcohol chosen from the group consisting of polyvinyl nitrate and acetate polyvinyl.

On donne ci-après une description détaillée de l'invention.A detailed description of the invention is given below.

Le procédé selon l'invention consiste donc dans une première étape à enrober des grains de poudre propulsive par une pellicule d'un matériau thermoplastique énergétique et dans une seconde étape à comprimer à chaud les grains de poudre ainsi enrobés.The method according to the invention therefore consists in a first step of coating grains of propellant powder with a film of an energetic thermoplastic material and in a second step of hot pressing the grains of powder thus coated.

Comme poudre propulsive on peut utiliser dans le cadre de la présente invention la plupart des poudres propulsives connues de l'homme de métier. On peut ainsi en particulier utiliser les poudres à simple base à la nitrocellulose ou les poudres dites "composites" constituées principalement par une nitramine comme l'hexogène ou l'octogène et par un liant organique tel qu'un polyuréthanne, un polyester, un acétobutyrate de cellulose seul ou en mélange avec de la nitrocellulose et de l'acétate de triéthylcitrate.As propellant powder, it is possible to use in the context of the present invention most of the propellant powders known to those skilled in the art. It is thus possible in particular to use powders with a simple nitrocellulose base or so-called "composite" powders constituted mainly by a nitramine such as hexogen or octogen and by an organic binder such as a polyurethane, a polyester, an acetobutyrate. cellulose alone or in admixture with nitrocellulose and triethyl citrate acetate.

On peut également dans le cadre de la présente invention utiliser des poudres contenant de la nitroglycérine ou plus généralement une huile nitrée comme les poudres dites à "double base" constituées par un mélange de nitrocellulose et de nitroglycérine ou les poudres dites "multibases" constituées par de la nitrocellulose, de la nitroglycérine et par un ou plusieurs composés énergétiques nitrés comme la nitroguanidine, l'hexogène, l'octogène, la pentrite, le dinitroglycolurile, etc...
Toutefois, pour ces poudres la demanderesse déconseille l'utilisation de poudres à fort taux de nitroglycérine pour éviter les risques de migration dans le temps de la nitroglycérine dans la pellicule d'enrobage des grains de poudre, phénomène qui risque de perturber la fragmentation du chargement au moment du tir. Dans la pratique la demanderesse recommande de ne pas utiliser de poudres dont la teneur en nitroglycérine ou en huile nitrée est supérieure à 25 % en poids.
Pour la plupart des chargements destinés aux armes de petit et moyen calibre on utilisera habituellement les poudres à simple base à la nitrocellulose.It is also possible in the context of the present invention to use powders containing nitroglycerin or more generally a nitrated oil such as so-called “double base” powders constituted by a mixture of nitrocellulose and nitroglycerine or powders called “multibase” constituted by nitrocellulose, nitroglycerin and one or more nitro energetic compounds such as nitroguanidine, hexogen, octogen, pentrite, dinitroglycolurile, etc ...
However, for these powders the applicant advises against the use of powders with a high level of nitroglycerin to avoid the risks of migration over time of nitroglycerine in the coating film of the powder grains, phenomenon which is likely to disturb the fragmentation of the load. when fired. In the In practice, the Applicant recommends not using powders with a nitroglycerin or nitrated oil content greater than 25% by weight.
For most shipments intended for small and medium caliber weapons, single nitrocellulose-based powders will usually be used.

La géométrie du grain de poudre dépendra des dimensions et des propriétés voulues pour le chargement fragmentable.The geometry of the powder grain will depend on the dimensions and properties desired for the fragmentable load.

Les grains de poudre, lissés ou non lissés, sont donc enrobés par une pellicule d'un matériau thermoplastique énergétique. Selon l'invention ce matériau est, de manière caractéristique, constitué par le mélange d'au moins un dinitropolystyrène, d'un stabilisant, et d'un dérivé de l'alcool polyvinylique choisi dans le groupe constitué par le nitrate de polyvinyle et l'acétate de polyvinyle. Selon l'invention le rapport pondéral entre le dinitropolystyrène et l'ensemble constitué par le dinitropolystyrène et le ou les dérivés de l'alcool polyvinylique doit être compris entre 25 % et 75 %.The powder grains, smoothed or unsmoothed, are therefore coated with a film of an energetic thermoplastic material. According to the invention, this material is typically constituted by the mixture of at least one dinitropolystyrene, a stabilizer, and a derivative of polyvinyl alcohol chosen from the group consisting of polyvinyl nitrate and l polyvinyl acetate. According to the invention, the weight ratio between the dinitropolystyrene and the assembly constituted by the dinitropolystyrene and the derivative (s) of polyvinyl alcohol must be between 25% and 75%.

Le dinitropolystyrène est un polymère organique de formule

Figure imgb0001

dans laquelle les symboles C, H, O, N représentent respectivement le carbone, l'hydrogène, l'oxygène et l'azote et n représente un nombre entier.Dinitropolystyrene is an organic polymer with the formula
Figure imgb0001
in which the symbols C, H, O, N represent carbon, hydrogen, oxygen and nitrogen respectively and n represents an integer.

Dans le cadre de la présente invention on peut utiliser des dinitropolystyrènes de différentes masses moléculaires mais on préfèrera ceux dont la température de ramollissement est supérieure à 260°C.In the context of the present invention, dinitropolystyrenes of different molecular weights can be used, but those whose softening temperature is higher than 260 ° C. are preferred.

Cette condition est réalisée avec les dinitropolystyrènes dont la masse moléculaire est voisine de 500 000, ce qui correspond à un indice de polymérisation n voisin de 2 000.This condition is achieved with dinitropolystyrenes whose molecular mass is close to 500,000, which corresponds to a polymerization index n close to 2,000.

Le dinitropolystyrène est avantageusement obtenu par nitration du polystyrène selon les techniques décrites, par exemple, dans les ouvrages suivants : Mémorial des Poudres, volume 35, 1953, pages 41 à 50 (Boileau, Pujo, Lang), Encyclopedia of Explosives and Relative Items, volume 8, 1978, pages 143-144, ou encore dans le brevet US 3 715 323.Dinitropolystyrene is advantageously obtained by nitration of polystyrene according to the techniques described, for example, in the following works: Mémorial des Poudres, volume 35, 1953, pages 41 to 50 (Boileau, Pujo, Lang), Encyclopedia of Explosives and Relative Items, volume 8, 1978, pages 143-144, or even in US patent 3,715,323.

Comme stabilisant du mélange on peut utiliser les stabilisants traditionnels des composés nitrés comme la diphénylamine ou la nitro-2 diphénylamine, néanmoins le stabilisant préféré est la nitro-2 diphénylamine. Ce stabilisant sera présent dans le mélange à raison d'environ 2 % en poids du poids total de l'ensemble dinitropolystyrène et dérivés de l'alcool polyvinylique.As stabilizer of the mixture, conventional stabilizers of nitro compounds such as diphenylamine or 2-nitro-diphenylamine can be used, however the preferred stabilizer is 2-nitro-diphenylamine. This stabilizer will be present in the mixture at a rate of approximately 2% by weight of the total weight of the dinitropolystyrene assembly and derivatives of polyvinyl alcohol.

Le mélange enrobant les grains de poudre contient donc au moins un dérivé de l'alcool polyivnylique choisi dans le groupe constitué par le nitrate de polyvinyle et l'acétate de polyvinyle. Il peut contenir simultanément ces deux dérivés. Selon une variante de réalisation de l'invention une partie des dérivés de l'alcool polyvinylique peut être remplacée par de l'acétate de cellulose mais, et il s'agit là d'une condition importante de mise en oeuvre de l'invention, l'acétate de cellulose ne peut pas remplacer en totalité les dérivés de l'alcool polyvinylique. Les dérivés de l'alcool polyvinylique, nitrate de polyvinyle et/ou acétate de polyvinyle, doivent représenter au moins un tiers en poids du poids total de l'ensemble acétate de cellulose + dérivés de l'alcool polyvinylique.The mixture coating the powder grains therefore contains at least one derivative of polyvinyl alcohol chosen from the group consisting of polyvinyl nitrate and polyvinyl acetate. It can simultaneously contain these two derivatives. According to an alternative embodiment of the invention, part of the derivatives of polyvinyl alcohol can be replaced by cellulose acetate but, and this is an important condition for implementing the invention, cellulose acetate cannot completely replace polyvinyl alcohol derivatives. The derivatives of polyvinyl alcohol, polyvinyl nitrate and / or polyvinyl acetate, must represent at least one third by weight of the total weight of the cellulose acetate + derivatives of polyvinyl alcohol.

En cas de remplacement partiel des dérivés de l'alcool polyvinylique par de l'acétate de cellulose, la condition générale relative à la composition pondérale du mélange d'enrobage demeure en se généralisant de la manière suivante :

Figure imgb0002

[DNPS]
= poids de dinitropolystyrène
[NPV]
= poids de nitrate de polyvinyle
[AcPV]
= poids d'acétate de polyvinyle
[AcCELL]
= poids d'acétate de cellulose,
avec pour mémoire :
Figure imgb0003
L'enrobage proprement dit des grains de poudre se fait au cours d'une opération d'enrobage durant laquelle on pulvérise sur les grains de poudre le mélange d'enrobage mis en solution dans un milieu solvant.In the event of partial replacement of the polyvinyl alcohol derivatives with cellulose acetate, the general condition relating to the weight composition of the coating mixture remains generalized as follows:
Figure imgb0002
[DNPS]
= weight of dinitropolystyrene
[NPV]
= weight of polyvinyl nitrate
[AcPV]
= weight of polyvinyl acetate
[AcCELL]
= weight of cellulose acetate,
with for memory:
Figure imgb0003
The actual coating of the powder grains is carried out during a coating operation during which the coating grains sprayed in solution in a solvent medium are sprayed onto the powder grains.

Le milieu solvant comprend au moins un solvant du dinitropolystyrène choisi dans le groupe constitué par la cyclohexanone, la tétraméthylurée, le nitrobenzène, la butyrolactone et la tétraméthylène sulfone encore connue sous la marque de commerce SULFOLANE® , de manière à assurer une bonne dissolution du dinitropolystyrène. Les solvants préférés du dinitropolystyrène dans le cadre de l'invention sont la cyclohexanone, la tétraméthylurée et la tétraméthylène sulfone.The solvent medium comprises at least one dinitropolystyrene solvent chosen from the group consisting of cyclohexanone, tetramethylurea, nitrobenzene, butyrolactone and tetramethylene sulfone still known under the trade name SULFOLANE®, so as to ensure good dissolution of the dinitropolystyrene . The preferred solvents for dinitropolystyrene in the context of the invention are cyclohexanone, tetramethylurea and tetramethylene sulfone.

Selon une variante de réalisation de l'invention, ledit solvant est utilisé en mélange avec un solvant auxiliaire qui est un bon solvant des dérivés de l'alcool polyvinylique et de l'acétate de cellulose. L'acétone est un solvant auxiliaire préféré dans le cadre de la présente invention. Cette solution offre en outre l'avantage de ne pas trop abaisser le potentiel de la poudre par l'opération d'enrobage.According to an alternative embodiment of the invention, said solvent is used in admixture with an auxiliary solvent which is a good solvent for derivatives of polyvinyl alcohol and cellulose acetate. Acetone is a preferred auxiliary solvent in the context of the present invention. This solution also offers the advantage of not lowering the potential of the powder too much by the coating operation.

La quantité de matériau d'enrobage déposé sur les grains de poudre doit représenter environ deux pour cents du poids de la poudre. Ce dépôt est effectué par pulvérisation de la solution de matériau d'enrobage sur les grains de poudre, par exemple dans un drageoir tournant comme pour une opération classique de lissage. Après pulvérisation de la solution, on assure l'élimination du milieu solvant par essorage à l'air éventuellement complété par un séchage en étuve, à pression atmosphérique ou sous vide.The amount of coating material deposited on the powder grains should be about two percent of the weight of the powder. This deposition is carried out by spraying the solution of coating material onto the powder grains, for example in a rotating bezel as for a conventional smoothing operation. After spraying the solution, the solvent medium is removed by air drying, optionally supplemented by drying in an oven, at atmospheric pressure or under vacuum.

Les grains de poudre ainsi enrobés sont alors comprimés à la forme et aux dimensions du chargement fragmentable désiré. Cette compression est avantageusement effectuée à une température comprise entre 100°C et 140°C. Une pression voisine de 100 bars, soit 10⁷ Pa, est en général suffisante pour les chargements usuels destinés aux armes de petit et moyen calibre.The powder grains thus coated are then compressed to the shape and dimensions of the desired fragmentable load. This compression is advantageously carried out at a temperature between 100 ° C and 140 ° C. A pressure close to 100 bars, or 10 soit Pa, is generally sufficient for the usual loads intended for small and medium-caliber weapons.

Cette deuxième étape du procédé peut intervenir soit immédiatement après la première étape soit ultérieurement dans le temps comme il est expliqué plus loin dans la description.This second step of the process can take place either immediately after the first step or later in time as explained later in the description.

L'invention concerne également les chargements propulsifs fragmentables ainsi obtenus.The invention also relates to the fragmentable propellant charges thus obtained.

Par "chargement" on entend au sens de la présente demande soit le chargement propulsif dans sa totalité s'il est constitué d'un seul élément, soit un élément constitutif du chargement si ce dernier est constitué par une pluralité d'éléments.By "load" is meant in the sense of the present application either the propellant load in its entirety if it consists of a single element, or an element constituting the load if the latter consists of a plurality of elements.

Ces chargements obtenus par agglomération de grains de poudre enrobés selon l'invention présentent une bonne tenue mécanique à froid et conservent encore une certaine tenue mécanique à 100°C, contrairement aux chargements obtenus par agglomération de grains de poudre enrobés seulement par du nitrate de polyvinyle. Par ailleurs les chargements selon l'invention présentent des propriétés balistiques comparables à celles des chargements traditionnels et notamment présentent, en combustion, une fragmentation tout à fait correcte.These loads obtained by agglomeration of powder grains coated according to the invention have good mechanical strength when cold and still retain a certain mechanical strength at 100 ° C., in contrast to the loads obtained by agglomeration of powder grains coated only with polyvinyl nitrate . Furthermore, the loads according to the invention have ballistic properties comparable to those of traditional loads and in particular exhibit, on combustion, a perfectly correct fragmentation.

Ils trouvent une application intéressante dans les munitions sans douille, notamment pour armes à grande cadence de tir.They find an interesting application in ammunition without cartridge case, in particular for weapons with high rate of fire.

Pour les armes à grande cadence de tir et à petit ou moyen calibre, on utilisera avantageusement les chargements propulsifs selon l'invention obtenus à partir de poudre propulsive à simple base à la nitrocellulose, cette poudre étant aujourd'hui la plus courante et la plus économique.For weapons with a high rate of fire and of small or medium caliber, the propellant charges according to the invention obtained from propellant powder with a simple nitrocellulose base will advantageously be used, this powder being the most common and the most common today. economic.

Enfin l'invention concerne aussi les poudres constitutives des chargements selon l'invention. Plus précisément l'invention concerne les grains de poudre propulsive obtenus à l'issue de la première étape du procédé selon l'invention après évaporation du milieu solvant. Ces grains de poudre sont enrobés par une pellicule d'un mélange contenant au moins un dinitropolystyrène, un stabilisant et un dérivé de l'alcool polyvinylique choisi dans le groupe constitué par le nitrate de polyvinyle et l'acétate de polyvinyle. L'invention concerne particulièrement les grains enrobés obtenus à partir d'une poudre à simple base à la nitrocellulose.
De tels grains de poudre se conservent bien dans le temps et peuvent être facilement transportés. Ils permettent ainsi de dissocier, dans le temps et même dans l'espace, les deux étapes du procédé selon l'invention, en fonction des besoins.Finally, the invention also relates to the powders constituting the loads according to the invention. More specifically, the invention relates to the propellant powder grains obtained at the end of the first step of the process according to the invention after evaporation of the solvent medium. These powder grains are coated with a film of a mixture containing at least one dinitropolystyrene, a stabilizer and a derivative of polyvinyl alcohol chosen from the group consisting of polyvinyl nitrate and polyvinyl acetate. The invention particularly relates to the coated grains obtained from a single-base nitrocellulose powder.
Such powder grains keep well over time and can be easily transported. They thus make it possible to dissociate, in time and even in space, the two stages of the method according to the invention, according to the needs.

Les exemples qui suivent illustrent certaines possibilités de mise en oeuvre de l'invention sans en limiter la portée.The examples which follow illustrate certain possibilities for implementing the invention without limiting its scope.

Exemple 1 - Exemple de référence Example 1 - Reference example

Pour cet exemple de référence on a fabriqué un chargement fragmentable à partir de poudre propulsive en grains enrobée par du seul nitrate de polyvinyle selon la technique décrite dans le brevet français 2 436 766.For this reference example, a fragmentable charge was made from propellant powder in grains coated with polyvinyl nitrate alone according to the technique described in French patent 2,436,766.

La poudre utilisée est une poudre classique à simple base à la nitrocellulose en grains cylindriques comportant un trou central, de web (épaisseur à brûler) 0,25 mm. Au départ la poudre est non lissée et non graphitée et son potentiel est de 4 034 joules/g soit 965 cal/g.The powder used is a conventional powder based on nitrocellulose in cylindrical grains having a central hole, web (thickness to be burned) 0.25 mm. At the start, the powder is not smoothed and not graphitized and its potential is 4,034 joules / g, ie 965 cal / g.

L'enrobage de la poudre se fait de la manière suivante : dans un drageoir chauffé à 25°C on introduit 5 kg de poudre, 2,5 g de graphite et on pulvérise en trois fois une solution d'enrobage dont la composition globale est la suivante : - nitrate de polyvinyle 2 % du poids de la poudre - acétone 20 % du poids de la poudre - éthanol 4 % du poids de la poudre - nitro-2 diphénylamine 0,04 % du poids de la poudre The powder is coated as follows: 5 kg of powder, 2.5 g of graphite are introduced into a bezel heated to 25 ° C. and a coating solution is sprayed, the overall composition of which is the next one : - polyvinyl nitrate 2% of the weight of the powder - acetone 20% of the weight of the powder - ethanol 4% of the weight of the powder - 2-nitro diphenylamine 0.04% by weight of the powder

La température de la solution d'enrobage est de 60°C, la température du drageoir étant de 25°C.The temperature of the coating solution is 60 ° C, the temperature of the pan being 25 ° C.

Après pulvérisation on laisse tourner le drageoir pendant 5 minutes portes ouvertes. La poudre enrobée est alors introduite dans un moule chauffé à 110°C, on laisse la poudre dans le moule pendant 5 minutes et on comprime pendant 1 minute sous 10⁷ Pa soit 100 bars. On obtient ainsi des blocs fragmentables cylindriques pleins de hauteur 22 mm et de diamètre 12,6 mm présentant les caractéristiques suivantes : potentiel 3 840 joules/g soit 918 cal/g aspect correct résistance à l'écrasement + 21°C : 0,60kN/cm² + 100°C : tenue mécanique trop faible pour pouvoir être mesurée. After spraying, the bezel is left to rotate for 5 minutes with the doors open. The coated powder is then introduced into a mold heated to 110 ° C., the powder is left in the mold for 5 minutes and it is compressed for 1 minute under 10⁷ Pa, ie 100 bars. Solid fragmentable cylindrical blocks 22 mm high and 12.6 mm in diameter are thus obtained, having the following characteristics: potential 3,840 joules / g or 918 cal / g aspect correct crush resistance + 21 ° C: 0.60 kN / cm² + 100 ° C: mechanical strength too weak to be able to be measured.

Exemples 2 à 6Examples 2 to 6

On a fabriqué des chargements fragmentables selon l'invention à partir de poudre propulsive en grains enrobée par un mélange de nitrate de polyvinyle (NPV) et de dinitropolystyrène (DNPS) en présence de nitro-2 diphénylamine (2-NDPA) comme stabilisant. La poudre utilisée était la même que celle de l'exemple 1 et on a procédé pour l'enrobage comme décrit dans l'exemple 1 avec des solutions d'enrobage dont les compositions globales étaient les suivantes : EX 2 EX 3 EX 4 EX 5 EX 6 NPV 1 % 0,5 % 1 % 1,2 % 1,5 % DNPS 1 % 1,5 % 1 % 0,8 % 0,5 % cyclohexanone 18 % 18 % 7 % 5,6 % 4 % acétone 0 % 0 % 15 % 18 % 18 % 2-NDPA 0,04 % 0,04 % 0,04 % 0,04 % 0,04 % Fragmentable charges according to the invention were made from propellant powder in grains coated with a mixture of polyvinyl nitrate (NPV) and dinitropolystyrene (DNPS) in the presence of 2-nitro diphenylamine (2-NDPA) as a stabilizer. The powder used was the same as that of Example 1 and the coating was carried out as described in Example 1 with coating solutions whose overall compositions were as follows: EX 2 EX 3 EX 4 EX 5 EX 6 NPV 1% 0.5% 1% 1.2% 1.5% DNPS 1% 1.5% 1% 0.8% 0.5% cyclohexanone 18% 18% 7% 5.6% 4% acetone 0% 0% 15% 18% 18% 2-NDPA 0.04% 0.04% 0.04% 0.04% 0.04%

Les pourcentages sont exprimés en poids par rapport au poids total de la poudre.
Le dinitropolystyrène utilisé avait un taux d'azote de 14,81 %, une masse moléculaire moyenne de 500 000 et un point de ramollissement supérieur à 260°C. C'est ce dinitropolystyrène qui a été utilisé dans tous les exemples.
La compression des grains enrobés a été faite de manière analogue à celle décrite dans l'exemple 1, la température de compression étant de 130°C.
On a obtenu des blocs analogues à ceux de l'exemple 1 et présentant les caractéristiques suivantes : EX 2 EX 3 EX 4 EX 5 EX 6 Potentiel (joules/g) 3 400 3 436 3 920 3 915 3 929 Potentiel (cal/g) 815 822 938 937 940 cyclohexanone 4 % 3,7 % 0,9 % 0,5 % 0,35 % aspect du bloc correct correct correct correct correct résistance à l'écrassement à 21°C en kN/cm² 0,50 0,55 0,90 0,56 0,60 résistance à l'écrassement à 100°C en kN/cm² 0,40 0,55 0,70 0,53 0,20 The percentages are expressed by weight relative to the total weight of the powder.
The dinitropolystyrene used had a nitrogen content of 14.81%, an average molecular weight of 500,000 and a softening point above 260 ° C. It is this dinitropolystyrene which was used in all the examples.
The compression of the coated grains was carried out in a similar manner to that described in Example 1, the compression temperature being 130 ° C.
Blocks similar to those of Example 1 and having the following characteristics were obtained: EX 2 EX 3 EX 4 EX 5 EX 6 Potential (joules / g) 3,400 3,436 3,920 3,915 3,929 Potential (cal / g) 815 822 938 937 940 cyclohexanone 4% 3.7% 0.9% 0.5% 0.35% block appearance correct correct correct correct correct resistance to crushing at 21 ° C in kN / cm² 0.50 0.55 0.90 0.56 0.60 resistance to crushing at 100 ° C in kN / cm² 0.40 0.55 0.70 0.53 0.20

Le pourcentage résiduel de cyclohexanone est exprimé en poids par rapport au poids total du chargement.The residual percentage of cyclohexanone is expressed by weight relative to the total weight of the load.

On constate que tous les chargements selon l'invention ont encore une certaine résistance à l'écrasement à + 100°C alors que le chargement de référence (exemple 1) n'a plus aucune résistance mécanique à cette température.It is noted that all the loadings according to the invention still have a certain resistance to crushing at + 100 ° C. whereas the reference load (example 1) no longer has any mechanical resistance at this temperature.

Par ailleurs, en vue de conserver des potentiels élevés on a intérêt à utiliser la cyclohexanone en mélange avec l'acétone (exemples 4, 5 et 6) plutôt que seule (exemples 2 et 3).Furthermore, in order to conserve high potentials, it is advantageous to use cyclohexanone in admixture with acetone (examples 4, 5 and 6) rather than alone (examples 2 and 3).

Enfin tous les tirs en bombe manométrique au moment de la détermination des potentiels, ont montré une très bonne fragmentation des chargements selon l'invention.Finally all the manometric bomb shots at the time of the determination of the potentials, have shown a very good fragmentation of the loadings according to the invention.

Example 7Example 7

On a fabriqué un chargement fragmentable selon l'invention à partir de poudre propulsive en grains enrobée par un mélange d'acétate de polyvinyle (AcPV) et de dinitropolystyrène (DNPS) en présence de nitro-2 diphénylamine (2-NDPA) comme stabilisant.A fragmentable charge according to the invention was made from propellant powder in grains coated with a mixture of polyvinyl acetate (AcPV) and dinitropolystyrene (DNPS) in the presence of 2-nitro diphenylamine (2-NDPA) as stabilizer.

La poudre utilisée est la même que celle de l'exemple 1. L'enrobage se fait de la manière suivante : dans un drageoir chauffé à 25°C on introduit 5 kg de poudre, 2,5 g de graphite et on pulvérise en quatre fois une solution d'enrobage dont la composition globale est la suivante : - AcPV 1 % du poids de la poudre - DNPS 1 % du poids de la poudre - cyclohexanone 10 % du poids de la poudre - acétone 10 % du poids de la poudre - 2-NDPA 0,04 % du poids de la poudre The powder used is the same as that of Example 1. The coating is carried out as follows: into a bezel heated to 25 ° C. 5 kg of powder, 2.5 g of graphite are introduced and sprayed in four times a coating solution whose overall composition is as follows: - AcPV 1% of the weight of the powder - DNPS 1% of the weight of the powder - cyclohexanone 10% of the weight of the powder - acetone 10% of the weight of the powder - 2-NDPA 0.04% by weight of the powder

La température de la solution d'enrobage était de 60°C. Après pulvérisation on a laissé tourner le drageoir pendant 5 minutes portes ouvertes puis on a mis la poudre à sécher en étuve pendant 16 heures à 60°C. La poudre enrobée a alors été introduite dans un moule chauffé à 130°C, on a laissé la poudre dans le moule pendant 5 minutes et on a comprimé pendant 1 minute sous 10⁷ Pa soit 100 bars. On a ainsi obtenu des blocs fragmentables cylindriques pleins de hauteur 22 mm et de diamètre 12,6 mm présentant les caractéristiques suivantes : aspect correct potentiel 3 770 joules/g soit 902 cal/g résistance à l'écrasement + 21°C : 1,01 kN/cm² + 100°C : 0,86 kN/cm² The temperature of the coating solution was 60 ° C. After spraying, the pan was left to rotate for 5 minutes with the doors open, then the powder was put to dry in an oven for 16 hours at 60 ° C. The coated powder was then introduced into a mold heated to 130 ° C., the powder was left in the mold for 5 minutes and was compressed for 1 minute at 10⁷ Pa, ie 100 bars. Solid cylindrical fragmentable blocks 22 mm high and 12.6 mm in diameter were thus obtained, having the following characteristics: aspect correct potential 3,770 joules / g or 902 cal / g crush resistance + 21 ° C: 1.01 kN / cm² + 100 ° C: 0.86 kN / cm²

Exemple 8Example 8

On a fabriqué un chargement fragmentable selon l'invention à partir de poudre propulsive en grains enrobée par un mélange de dinitropolystyrène (DNPS), de nitrate de polyvinyle (NPV) et d'acétate de polyvinyle (AcPV) en présence de nitro-2 diphénylamine (2-NDPA) comme stabilisant.A fragmentable charge according to the invention was made from propellant powder in grains coated with a mixture of dinitropolystyrene (DNPS), polyvinyl nitrate (NPV) and polyvinyl acetate (AcPV) in the presence of 2-nitro diphenylamine (2-NDPA) as a stabilizer.

On a procédé comme décrit dans l'exemple 7 avec une solution d'enrobage dont la composition globale était la suivante : - DNPS 0,67 % du poids de la poudre - NPV 0,67 % du poids de la poudre - AcPV 0,67 % du poids de la poudre - 2-NDPA 0,04 % du poids de la poudre - cyclohexanone 10 % du poids de la poudre - acétone 10 % du poids de la poudre The procedure was as described in Example 7 with a coating solution whose overall composition was as follows: - DNPS 0.67% of the weight of the powder - NPV 0.67% of the weight of the powder - AcPV 0.67% of the weight of the powder - 2-NDPA 0.04% by weight of the powder - cyclohexanone 10% of the weight of the powder - acetone 10% of the weight of the powder

On a ainsi obtenu des blocs fragmentables présentant les caractéristiques suivantes : aspect correct potentiel 3 860 joules/g soit 924 cal/g résistance à l'écrasement + 21°C : 0,66 kN/cm² + 100°C : 0,44 kN/cm² Fragmentable blocks were thus obtained having the following characteristics: aspect correct potential 3,860 joules / g or 924 cal / g crush resistance + 21 ° C: 0.66 kN / cm² + 100 ° C: 0.44 kN / cm²

Les exemples 7 et 8 démontrent que l'acétate de polyvinyle peut remplacer, en toutes proportions, le nitrate de polyvinyle dans le cadre de la présente invention.Examples 7 and 8 demonstrate that polyvinyl acetate can replace polyvinyl nitrate in all proportions in the context of the present invention.

Exemple 9Example 9

On a fabriqué un chargement fragmentable selon l'invention à partir de poudre propulsive en grains enrobée par un mélange de dinitropolystyrène (DNPS), de nitrate de polyvinyle (NPV) et d'acétate de cellulose (AcCell) en présence de nitro-2 diphénylamine (2-NDPA) comme stabilisant.A fragmentable charge according to the invention was made from propellant powder in grains coated with a mixture of dinitropolystyrene (DNPS), polyvinyl nitrate (NPV) and cellulose acetate (AcCell) in the presence of 2-nitro diphenylamine (2-NDPA) as a stabilizer.

On a procédé comme décrit dans l'exemple 7 avec une solution d'enrobage dont la composition globale était la suivante : - DNPS 0,67 % du poids de la poudre - NPV 0,67 % du poids de la poudre - AcCell 0,67 % du poids de la poudre - cyclohexanone 10 % du poids de la poudre - acétone 10 % du poids de la poudre - 2-NDPA 0,04 % du poids de la poudre We proceeded as described in Example 7 with a solution coating whose overall composition was as follows: - DNPS 0.67% of the weight of the powder - NPV 0.67% of the weight of the powder - AcCell 0.67% of the weight of the powder - cyclohexanone 10% of the weight of the powder - acetone 10% of the weight of the powder - 2-NDPA 0.04% by weight of the powder

On a ainsi obtenu des blocs fragmentables présentant les caractéristiques suivantes : aspect correct potentiel 3 854 joules/g soit 922 cal/g résistance à l'écrasement + 21°C : 0,24 kN/cm² + 100°C : 0,23 kN/cm² Fragmentable blocks were thus obtained having the following characteristics: aspect correct potential 3,854 joules / g or 922 cal / g crush resistance + 21 ° C: 0.24 kN / cm² + 100 ° C: 0.23 kN / cm²

Exemple 10Example 10

On a essayé de fabriquer un chargement fragmentable à partir de poudre propulsive en grains enrobée par un mélange de dinitropolystyrène (DNPS) et d'acétate de cellulose (AcCell) en présence de nitro-2 diphénglamine (2-NDPA) comme stabilisant.We tried to make a fragmentable charge from propellant powder coated with a mixture of dinitropolystyrene (DNPS) and cellulose acetate (AcCell) in the presence of 2-nitro diphenglamine (2-NDPA) as stabilizer.

On a procédé comme décrit dans l'exemple 7 avec une solution d'enrobage dont la composition globale était la suivante : - DNPS 1 % du poids de la poudre - AcCell 1 % du poids de la podure - 2-NDPA 0,04 % du poids de la poudre - cyclohexanone 10 % du poids de la poudre - acétone 10 % du poids de la poudre The procedure was as described in Example 7 with a coating solution whose overall composition was as follows: - DNPS 1% of the weight of the powder - AcCell 1% of the weight of the podure - 2-NDPA 0.04% by weight of the powder - cyclohexanone 10% of the weight of the powder - acetone 10% of the weight of the powder

Si l'enrobage des grains de poudre ne pose aucun problème, il s'avère par contre impossible d'obtenir par compression un bloc qui se tienne à partir des grains de poudre ainsi enrobés.If the coating of the powder grains poses no problem, it turns out to be impossible to obtain by compression a block which is held from the powder grains thus coated.

La comparaison des exemples 9 et 10 montre qui si l'acétate de cellulose peut remplacer en partie les dérivés de l'alcool polyvinylique, il ne peut pas les remplacer en totalité dans le cadre de la présente invention.The comparison of Examples 9 and 10 shows that if cellulose acetate can partially replace the polyvinyl alcohol derivatives, it cannot completely replace them in the context of present invention.

Exemple 11Example 11

On a fabriqué un chargement fragmentable selon l'invention à partir de poudre propulsive en grains enrobée par un mélange de dinitropolystyrène (DNPS) et de nitrate de polyvinyle (NPV) en présence de nitro-2 diphénylamine (2-NDPA) comme stabilisant et en utilisant le nitrobenzène comme solvant.A fragmentable charge according to the invention was made from propellant powder in grains coated with a mixture of dinitropolystyrene (DNPS) and polyvinyl nitrate (NPV) in the presence of 2-nitro diphenylamine (2-NDPA) as stabilizer and using nitrobenzene as solvent.

On a procédé comme décrit dans l'exemple 7 avec une solution d'enrobage dont la composition globale était la suivante : - DNPS 1 % du poids de la poudre - NPV 1 % du poids de la poudre - 2-NDPA 0,04 % du poids de la poudre - nitrobenzène 15 % du poids de la poudre The procedure was as described in Example 7 with a coating solution whose overall composition was as follows: - DNPS 1% of the weight of the powder - NPV 1% of the weight of the powder - 2-NDPA 0.04% by weight of the powder - nitrobenzene 15% of the weight of the powder

On a ainsi obtenu des blocs fragmentables présentant les caractéristiques suivantes : aspect correct potentiel 3 460 joules/g soit 828 cal/g résistance à l'écrasement + 21°C : 0,49 kN/cm² + 100°C : 0,23 kN/cm² Fragmentable blocks were thus obtained having the following characteristics: aspect correct potential 3,460 joules / g or 828 cal / g crush resistance + 21 ° C: 0.49 kN / cm² + 100 ° C: 0.23 kN / cm²

Exemple 12Example 12

On a fabriqué un chargement fragmentable selon l'invention à partir de poudre propulsive en grains enrobée par un mélange de dinitropolystyrène (DNPS) et de nitrate de polyvinyle (NPV) en présence de nitro-2 diphénylamine (2-NDPA) comme stabilisant et en utilisant la tétraméthylurée comme solvant.A fragmentable charge according to the invention was made from propellant powder in grains coated with a mixture of dinitropolystyrene (DNPS) and polyvinyl nitrate (NPV) in the presence of 2-nitro diphenylamine (2-NDPA) as stabilizer and using tetramethylurea as a solvent.

On a procédé comme décrit dans l'exemple 7 avec une solution d'enrobage dont la composition globale était la suivante : - DNPS 1 % du poids de la poudre - NPV 1 % du poids de la poudre - 2-NDPA 0,04 % du poids de la poudre - tétraméthylurée 15 % du poids de la poudre The procedure was as described in Example 7 with a coating solution whose overall composition was as follows: - DNPS 1% of the weight of the powder - NPV 1% of the weight of the powder - 2-NDPA 0.04% by weight of the powder - tetramethylurea 15% of the weight of the powder

On a ainsi obtenu des blocs fragmentables présentant les caractéristiques suivantes : aspect correct potentiel 3 680 joules/g soit 880 cal/g résistance à l'écrasement + 21°C : 1,89 kN/cm² + 100°C : 1,04 kN/cm² Fragmentable blocks were thus obtained having the following characteristics: aspect correct potential 3,680 joules / g or 880 cal / g crush resistance + 21 ° C: 1.89 kN / cm² + 100 ° C: 1.04 kN / cm²

Exemple 13Example 13

On a fabriqué un chargement fragmentable selon l'invention à partir de poudre propulsive en grains enrobée par un mélange de dinitropolystyrène (DNPS) et de nitrate de polyvinyle (NPV) en présence de nitro-2 diphénylamine (2-NDPA) comme stabilisant et en utilisant la butyrolactone comme solvant.A fragmentable charge according to the invention was made from propellant powder in grains coated with a mixture of dinitropolystyrene (DNPS) and polyvinyl nitrate (NPV) in the presence of 2-nitro diphenylamine (2-NDPA) as stabilizer and using butyrolactone as solvent.

On a procédé comme décrit dans l'exemple 7 avec une solution d'enrabage dont la composition globale était la suivante : - DNPS 1 % du poids de la poudre - NPV 1 % du poids de la poudre - 2-NDPA 0,04 % du poids de la poudre - butyrolactone 15 % du poids de la poudre The procedure was as described in Example 7 with a coating solution whose overall composition was as follows: - DNPS 1% of the weight of the powder - NPV 1% of the weight of the powder - 2-NDPA 0.04% by weight of the powder - butyrolactone 15% of the weight of the powder

On a ainsi obtenu des blocs fragmentables présentant les caractéristiques suivantes : aspect correct potentiel 3 106 joules/g soit 743 cal/g résistance à l'écrasement + 21°C : 0,85 kN/cm² + 100°C : 0,29 kN/cm² Fragmentable blocks were thus obtained having the following characteristics: aspect correct potential 3,106 joules / g or 743 cal / g crush resistance + 21 ° C: 0.85 kN / cm² + 100 ° C: 0.29 kN / cm²

Exemple 14Example 14

On a fabriqué un chargement fragmentable selon l'invention à partir de poudre propulsive en grains enrobée par un mélange de dinitropolystyrène (DNPS) et de nitrate de polyvinyle (NPV) en présence de nitro-2 diphénylamine (2-NDPA) comme stabilisant et en utilisant la tétraméthylène sulfone comme solvant.A fragmentable charge according to the invention was made from propellant powder in grains coated with a mixture of dinitropolystyrene (DNPS) and polyvinyl nitrate (NPV) in the presence of 2-nitro diphenylamine (2-NDPA) as stabilizer and using tetramethylene sulfone as solvent.

On a procédé comme décrit dans l'exemple 7 avec une solution d'enrobage dont la composition globale était la suivante : - DNPS 1 % du poids de la poudre - NPV 1 % du poids de la poudre - acétone 12 % du poids de la poudre - tétraméthylène sulfone 6 % du poids de la poudre - 2-NDPA 0,04 % du poids de la poudre The procedure was as described in Example 7 with a coating solution whose overall composition was as follows: - DNPS 1% of the weight of the powder - NPV 1% of the weight of the powder - acetone 12% of the weight of the powder - tetramethylene sulfone 6% of the weight of the powder - 2-NDPA 0.04% by weight of the powder

On a ainsi obtenu des blocs fragmentables présentant les caractéristiques suivantes : aspect correct potentiel 3 712 joules/g soit 886 cal/g résistance à l'écrasement + 21°C : 1,1 kN/cm² + 100°C : 0,6 kN/cm² Fragmentable blocks were thus obtained having the following characteristics: aspect correct potential 3,712 joules / g or 886 cal / g crush resistance + 21 ° C: 1.1 kN / cm² + 100 ° C: 0.6 kN / cm²

Exemple 15Example 15

On a fabriqué un chargement fragmentable selon l'invention en utilisant comme poudre propulsive une poudre composite dont la composition était la suivante : - hexogène (enrobé avec 2 % en poids de phtalate de dioctyle) 80 parties en poids - centralite 0,4 parties en poids - nitrocellulose (taux d'azote 11,8 %) 4 parties en poids - acétobutyrate de cellulose 9,6 parties en poids - ATEC 6 parties en poids A fragmentable charge was made according to the invention using a composite powder, the composition of which was as follows: - hexogen (coated with 2% by weight of dioctyl phthalate) 80 parts by weight - centrality 0.4 parts by weight - nitrocellulose (nitrogen content 11.8%) 4 parts by weight - cellulose acetate butyrate 9.6 parts by weight - ATEC 6 parts by weight

L'abréviation ATEC désigne l'acétate de triéthylcitrate de formule :

Figure imgb0004

Le potentiel de cette poudre était de 3 595 joules/g soit 860 cal/g. Avec cette poudre on a procédé comme décrit dans l'exemple 7 avec une solution d'enrobage dont la composition globale était la suivante : - nitrate de polyvinyle 0,67 % du poids de la poudre - acétate de polyvinyle 0,67 % du poids de la poudre - dinitropolystyrène 0,67 % du poids de la poudre - cyclohexanone 10 % du poids de la poudre - acétone 10 % du poids de la poudre The abbreviation ATEC designates triethyl citrate acetate of formula:
Figure imgb0004
The potential of this powder was 3,595 joules / g or 860 cal / g. With this powder we proceeded as described in Example 7 with a coating solution whose overall composition was as follows: - polyvinyl nitrate 0.67% of the weight of the powder - polyvinyl acetate 0.67% of the weight of the powder - dinitropolystyrene 0.67% of the weight of the powder - cyclohexanone 10% of the weight of the powder - acetone 10% of the weight of the powder

On a ainsi obtenu des blocs fragmentables présentant les caractéristiques suivantes : aspect correct potentiel 3 574 joules/g soit 855 cal/g résistance à l'écrasement + 21°C : 0,89 kN/cm² + 100°C : 0,59 kN/cm² Fragmentable blocks were thus obtained having the following characteristics: aspect correct potential 3,574 joules / g or 855 cal / g crush resistance + 21 ° C: 0.89 kN / cm² + 100 ° C: 0.59 kN / cm²

Claims (13)

  1. Process for the manufacture of fragmentable propellent charges for cartridge-less ammunition from propellent powder in grain form, characterized in that in a first stage the said grains of powder are first of all subjected to a coating operation during which the grains of powder are sprayed with a mixture containing at least one dinitropolystyrene, a stabilizer and a polyvinyl alcohol derivative chosen from the group consisting of polyvinyl nitrate and polyvinyl acetate, the said mixture being in solution in a solvent medium and in that, after evaporation of the said solvent medium, in a second stage the powder grains thus obtained are compressed between approximately 100°C and 140°C.
  2. Process according to Claim 1, characterized in that the weight ratio of the dinitropolystyrene to the combination of dinitropolystyrene and the polyvinyl alcohol derivative is between 25 % and 75 %.
  3. Process according to Claim 2, characterized in that the said dinitropolystyrene has a softening point higher than 260°C.
  4. Process according to Claim 2, characterized in that the said stabilizer is 2-nitrodiphenylamine.
  5. Process according to Claim 2, characterized in that a proportion of the polyvinyl alcohol derivatives is replaced with cellulose acetate.
  6. Process according to any one of Claims 1 to 5, characterized in that the said solvent medium includes at least one solvent for dinitropolystyrene, chosen from the group consisting of cyclohexanone, tetramethylurea, nitrobenzene, butyrolactone and tetramethylene sulphone.
  7. Process according to Claim 6, characterized in that the said solvent for dinitropolystyrene is mixed with at least one auxiliary solvent which is a solvent for polyvinyl alcohol derivatives and for cellulose acetate.
  8. Process according to Claim 7, characterized in that the said auxiliary solvent is acetone.
  9. Process according to Claim 8, characterized in that the said solvent for dinitropolystyrene is cyclohexanone.
  10. Fragmentable charges of propellent powder in grain form, characterized in that they are obtained by the process according to any one of Claims 1 to 9.
  11. Charges according to Claim 10, characterized in that the said propellent powder in grain form is a single-base powder containing nitrocellulose.
  12. Propellent powder in grain form characterized in that the said grains are coated with a film of a mixture containing at least one dinitropolystyrene, a stabilizer and a polyvinyl alcohol derivative chosen from the group consisting of polyvinyl nitrate and polyvinyl acetate.
  13. Powder according to Claim 12, characterized in that the said propellent powder in grain form is a single-base powder containing nitrocellulose.
EP19910400319 1990-02-21 1991-02-11 Process for fabricating high temperature resistant fragmentable propellant charges, the charges thus obtained and their constituent powders Expired - Lifetime EP0446085B1 (en)

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FR9002092A FR2658505B1 (en) 1990-02-21 1990-02-21 METHOD FOR MANUFACTURING FRAGMENTABLE PROPULSIVE LOADS RESISTANT TO TEMPERATURE, CONSTITUENT POWDERS AND LOADS THUS OBTAINED.
FR9002092 1990-02-21

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EP0633236A1 (en) * 1993-06-30 1995-01-11 Alliant Techsystems Inc. Energetic gun propellant coating
DE19907809C2 (en) * 1999-02-24 2002-10-10 Nitrochemie Gmbh Process for the production of one-, two- or three-base propellant charge powders for gun ammunition
FR2899228B1 (en) * 2006-03-31 2012-01-13 Commissariat Energie Atomique SYNTHESIS OF BENZENIC COMPOUNDS SUBSTITUTED WITH NITRO AND VINYL GROUPS, 1,3-DINITRO-4,6-DIVINYLBENZENE AND ITS APPLICATIONS

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BE475809A (en) * 1946-09-04
US3154448A (en) * 1961-11-28 1964-10-27 Borden Co Dinitropolystyrene explosive composition
US3655836A (en) * 1968-06-26 1972-04-11 Hercules Inc Process for preparation of molded propellant charges from smokeless powder and nonvolatile binders
FR2166614A5 (en) * 1971-12-31 1973-08-17 Poudres & Explosifs Ste Nale Explosive compsn - with nitrated binder
FR2436766A1 (en) * 1978-09-21 1980-04-18 Poudres & Explosifs Ste Nale FRAGMENTABLE LOADS OF PROPULSIVE POWDER COATED WITH POLYVINYL NITRATE AND THEIR MANUFACTURING METHOD
DE3027361C1 (en) * 1980-07-18 1984-05-30 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V., 8000 München Explosives, in particular for shaped charges
FR2587328B1 (en) * 1985-09-19 1991-06-14 Poudres & Explosifs Ste Nale HIGH TEMPERATURE RESISTANT MIXED PROPELLANT LOADS

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DE69111097T2 (en) 1996-04-04

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