Energetic plasticized propellant

Abstract

An energetic composition comprising the following components in the following relative proportions:Component A: from 5% to 25% by weight of a polymeric binder;Component B: from 65% to 90% by weight of a highly energetic filler comprising at least one heteroalicyclic nitramine compound; andComponent C: from 1% to 15% by weight of a plasticiser which comprises at least one nitroaromatic compound; the percentages by weight of Components A, B and C adding to 100%.

Description

The present invention relates to energetic materials, particularly polymer bonded explosives and gun propellants and compositions suitable therefor.

Gun propellants have for many years been produced from compositions containing blends of nitrocellulose and nitroglycerine and are therefore known as double base materials. In some cases additional energetic ingredients such as picrite are added and the propellants are known as triple compositions. For high energy applications, e.g. the propulsion of kinetic energy projectiles from an armoured tank gun, highly energetic components such as nitramines have been included in double and triple base compositions.

Double and triple base compositions, particularly for high energy applications, suffer from the disadvantage that they are highly vulnerable to unwanted ignition when subjected in a hostile environment to attack by an energetic projectile, e.g. a projectile comprising a shaped warhead charge.

Recent approaches to the problem of vulnerability have involved the development of compositions which are essentially non-double base or-triple base systems. Although such systems can provide reduced vulnerability this is, in general terms, obtained at the expense of propellant energy.

It is an object of the present invention to provide improved insensitive energetic materials, especially plastic bonded explosives and gun propellant compositions for low vulnerability applications.

According to the present invention there is provided an energetic composition comprising the following components in the following relative proportions:

Component A: from 5% to 25% by weight of a polymeric binder;

Component B: from 65% to 90% by weight of a highly energetic filler comprising at least one heteroalicyclic nitramine compound; and

Component C: from 1% to 15% by weight of a plasticiser which comprises at least one nitroaromatic compound; the percentages by weight of Components A, B and C adding to 100%.

In compositions according to the present invention Component B essentially provides the high energy capability of the composition (although Component C makes and optionally Component A may make a minor contribution), Component A provides the required structural binder properties and Component C provides processibility enabling mixtures to be formed together with Components A and B and which may be worked into a suitable dough-like material which may be pressed or extruded to form suitable products, e.g., propellants. The mutual combination of these components is specially selected in compositions according to the present invention because of the unexpected advantages such a combination provides as follows.

We have found that compositions according to the present invention can be suitably processed to provide energetic materials, e.g., for use propellants which unexpectedly and beneficially can show an improved vulnerability but without a corresponding decrease in energy normally associated with such an improvement.

For example, propellant compositions embodying the present invention generally have a high ignition temperature and possess also the beneficial properties of relatively low flame temperatures for the level of energy involved, thereby affording the possibility of reduced barrel erosion, as well as a relatively low burning rate, the latter property beneficially allowing propellants to be made with small web sizes as described below. The compositions according to the present invention therefore can have a combination of properties which are especially suitable for the formulation of propellants for low vulnerability applications.

Preferably Component A comprises from 10% to 25% by weight, Component B comprises 70% to 90% by weight and Component C comprises 3% to 12% by weight, of the said composition.

Component C preferably comprises one or more compounds which melt at a temperature less than 100.degree. C. and desirably is a liquid at room temperature (20.degree. C.). Preferably, the or each said nitro compound of Component C is a monocyclic nitroaromatic compound; it may be a mono-nitro compound but preferably is a di- or tri-nitro compound or a mixture thereof.

Especially suitable as compounds for use in or as Component C are di- and tri-nitro benzenes or alkyl- or alkoxy-benzenes optionally containing substituent groups in the aromatic ring or in the alkyl or alkoxy group(s). For example, the compound may be a di- or tri-nitro derivative of an optionally substituted alkyl- or alkoxy-benzene containing from 1 to 3 optionally substituted alkyl and/or alkoxy groups each having from 1 to 4 carbon atoms. The compound may for instance be a di- or tri-nitro derivative of an optionally substituted toluene, ethylbenzene, propylbenzene, butylbenzene, xylene, methylethylbenzene, diethylbenzene or mesitylene or one of the other families to which the compounds listed below belong.

As optional substituents for the aromatic ring in addition to nitro group(s) and alkyl or alkoxy group(s) where present in the said nitroaromatic compound(s) of Component C, are preferred groups other than halogens selected from OH, SH, N.sub.3, NR.sub.1 R.sub.2, CO.OR.sub.3 or O.OCR.sub.4 where R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are each independently H or a simple alkyl or alkoxy (containing from 1 to 4 carbon atoms) or phenyl.

Component C may for example comprise one or more of the following known compounds (where M.P./.degree. C. is the melting point in degrees Celsius):

______________________________________CompoundNo. Name M.P./.degree.C.______________________________________1 1-amino-2,4-dimethyl-3-nitrobenzene 81-822 1-amino-3,4-dimethyl-2-nitrobenzene 65-663 1-amino-3,5-dimethyl-2-nitrobenzene 564 2-amino-1,3-dimethyl-4-nitrobenzene 81-825 2-amino-1,5-dimethyl-3-nitrobenzene 766 5-amino-1,2-dimethyl-3-nitrobenzene 74-757 1-amino-2-methoxy-3-nitrobenzene 678 1,3-dihydroxy-2-nitrobenzene 87-889 1,2-dimethoxy-3-nitrobenzene 64-6510 1,2-dimethoxy-4-nitrobenzene 9811 1,3-dimethoxy-2-nitrobenzene 8912 1,4-dimethoxy-2-nitrobenzene 72-7313 2,4-dimethoxy-l-nitrobenzene 76-7714 1,2-dimethyl-3,4-dinitrobenzene 8215 1,2-dimethyl-3,5-dinitrobenzene 7716 1,3-dimethyl-2,5-dinitrobenzene 10117 1,4-dimethyl-2,3-dinitrobenzene 9318 2,3-dimethyl-1,4-dinitrobenzene 89-9019 1,2-dimethyl-4-hydroxy-5-nitrobenzene 8720 1,3-dimethyl-2-hydroxy-4-nitrobenzene 99-10021 1,4-dimethyl-2-hydroxy-3-nitrobenzene 34-3522 1,5-dimethyl-2-hydroxy-3-nitrobenzene 7323 1,5-dimethyl-3-hydroxy-2-nitrobenzene 66-66.524 2,5-dimethyl-1-hydroxy-3-nitrobenzene 9125 1,2-dimethyl-3-nitrobenzene 1526 1,2-dimethyl-4-nitrobenzene 30-3127 1,3-dimethyl-2-nitrobenzene 1328 1,3-dimethyl-5-nitrobenzene 7529 1,4-dimethyl-2-nitrobenzene --30 2,4-dimethyl-1-nitrobenzene 931 1,3-dinitrobenzene 9032 1,3-dinitro-2-ethoxybenzene 59.5-60.533 1,3-dinitro-5-ethoxybenzene 97.534 1,4-dinitro-2-ethoxybenzene 96-9835 2,4-dinitro-1-ethoxybenzene 86-8736 1,3-dinitro-5-isopropyl-4-hydroxy- 55.56-methylbenzene37 1,2-dinitro-4-methoxybenzene 7138 1,3-dinitro-5-methoxybenzene 205.539 1,4-dinitro-2-methoxybenzene 9740 2,4-dinitro-1-methoxybenzene 94.5-95.541 2,4-dinitro-1,3,5-trimethyl-benzene 8642 1-ethoxy-2-nitrobenzene 243 1-ethoxy-4-nitrobenzene 6044 1-ethyl-2-nitrobenzene -2345 1-ethyl-3-nitrobenzene --46 1-ethyl-4-nitrobenzene -1247 1-isobutoxy-2-nitrobenzene (oil)48 4-isopropyl-1-methyl-2-nitrobenzene --49 1-isopropyl-2-nitrobenzene --50 1-isopropyl-4-nitrobenzene --51 1-mercapto-2-nitrobenzene 58.552 1-mercapto-4-nitrobenzene 7953 1-methoxy-2-nitrobenzene 1054 1-methoxy-3-nitrobenzene 38-3955 1-methoxy-4-nitrobenzene 5456 2-methoxy-1,3,5-trinitrobenzene 6957 nitrobenzene 5.758 1-nitro-2-triazobenzene 53-5559 1-nitro-3-triazobenzene 5660 1-nitro-4-triazobenzene 7561 1-nitro-2,3,5-trimethylbenzene 2062 1-nitro-2,4,5-trimethylbenzene 7163 2-nitro-1,3,5-trimethylbenzene 4464 1,2,4-trinitrobenzene 61-6265 1,3,5-trinitrobenzene --66 N-(2-nitrophenyl)-benzamide 9867 2-nitrophenyl benzoate 8568 3-nitrophenyl benzoate 71-7269 4-nitrophenyl benzoate 94-9570 2,4-dinitrotoluene 7171 2,5-dinitrotoluene 5372 2,6-dinitrotoluene 6673 3,4-dinitrotoluene 5874 2,4-dinitro-6-hydroxytoluene 8675 3,5-dinitro-4-hydroxytoluene 8576 2-hydroxy-3,4,5-trinitrotoluene 10277 3-hydroxy-2,4,6-trinitrotoluene 109-11078 2,4,6-trinitrotoluene 82______________________________________

Preferably, at least 50% by weight of Component C comprises one or more alkyl substituted monocyclic dinitrobenzenes, e.g. selected from dinitrotoluenes, dinitroethylbenzenes and dinitropropylbenzenes.

Nitroaromatic compounds as described above have been found to provide energetic plasticisers which are compatible with nitramine energetic fillers and are highly suitable for use in processing mixtures of such fillers with polymeric binders. Preferably, the nitroaromatic plasticiser has an ignition temperature greater than 200.degree. C.

Nitroaromatic compounds as described above are known or may be made by well known methods.

For example, in the production of nitro derivatives of alkylbenzenes the appropriate alkylbenzene is treated with concentrated nitric and sulphuric acid at a temperature less than 40.degree. C. Where the product obtained is a mixture of nitro compounds, e.g. containing dinitro- and trinitro derivatives, such a mixture may itself be suitable for use in or as Component C.

Although Component C desirably comprises one or more monocyclic nitroaromatic compounds, e.g. so that the monocyclic nitro compound(s) forms at least 50 per cent by weight of Component C, it may also include one or more nitroaromatic compounds containing more than one aromatic ring, e.g. one or more of the 2-ring esters listed above or one or more nitro derivatives of biphenyl, naphthalene diphenylmethane, bibenzyl or stilbene preferably containing two or three nitro groups in each ring. An example is 2,2',4,4',6,6'-hexanitrostilbene.

Although Component C is preferably constituted entirely by nitroaromatic compounds as described above it could also include other energetic and non-energetic plasticisers as optional additives. For example, Component C may additionally include a quantity of one or more known energetic plasticisers such as GAP (glycidyl azide polymer), BDNPA/F (bis-2,2-dinitropropylacetal/formal), dimethylmethylene dinitroamine, bis(2,2-dinitropropyl)formal, bis(2,2,2-trinitroethyl)formal, bis(2-fluoro-2,2-dinitroethyl)formal, diethylene glycol dinitrate, glycerol trinitrate, glycol trinitrate, triethylene glycol dinitrate, tetrethylene glycol dinitrate, trimethylolethane trinitrate, butanetriol trinitrate, or 1,2,4-butanetriol trinitrate. Alternatively, or in addition, Component C may include one or more known non-energetic plasticisers such as dialkyl esters of adipic or phthalic acid, e.g., dibutyl phthalate, or diethyl phthalate, triacetin, tricresyl phosphate, polyalkylene glycols and their alkyl ether derivatives, e.g. polyethylene glycol, polypropylene glycol, and diethylene glycol butylether. However, preferably at least 50% desirably at least 75% by weight of Component C is constituted by one or more nitroaromatic compounds.

In the composition according to the present invention Component A may be any suitable polymer binder. It may comprise an inert binder material, an energetic binder material or a blend of inert and energetic binder materials. However, generally speaking, increasing the energetic nature of the binder increases the sensitiveness and-explosiveness of the energetic material formed therefrom. Therefore employed binders which are energetic are desirably not highly energetic. For example where the binder comprises a blend of inert and energetic materials the inert material preferably forms at least 50% by weight of the binder.

Examples of suitable inert or non-energetic binder materials are cellulosic materials such as esters, e.g. cellulose acetate, cellulose acetate butyrate, polyurethanes, polyesters, polybutadienes, polyethylenes, polyvinyl acetate and blends and/or copolymers thereof.

Examples of suitable energetic binder materials are nitrocellulose, polyvinyl nitrate, nitroethylene, nitroallyl acetate, nitroethyl acrylate, nitroethyl methacrylate, trinitroethyl acrylate, dinitropropyl acrylate, C-nitropolystyrene and its derivatives, polyurethanes with aliphatic C- and N- nitro groups, polyesters made from dinitrocarboxylic acids and dinitrodiols.

We prefer cellulosic materials for Component A comprising 0 to 60 per cent by weight of nitrocellulose, e.g., containing 12 to 14 per cent by weight N, and 100 to 40 per cent by weight of an inert cellulose ester, e.g., cellulose acetate, or cellulose acetate butyrate.

Preferably, Component B comprises a solid granular or powdered material which can be uniformly incorporated in Component A.

Preferably at least 75% desirably at least 90% by weight of Component B is constituted by one or more heteroalicyclic nitramine compounds. Nitramine compounds are those containing at least one N-NO.sub.2 group. Heteroalicyclic nitramines bear a ring containing N-NO.sub.2 groups. Such ring or rings may contain for example from two to ten carbon atoms and from two to ten ring nitrogen atoms. Examples of preferred heteroalicyclic nitramines are RDX (cyclo -1,3,5-trimethylene-2,4,6-trinitramine, cyclonite or Hexagen), HMX (cyclo -1,3,5,7-tetramethylene -2,4,6,8-tetranitramine, Octogen) or TATND (tetranitro-tetraminodecalin) and mixtures thereof.

Preferably, Component B comprises from 50% to 100% by weight of RDX. Desirably, for propellants, the composition includes from 70 to 80 per cent by weight of RDX.

Other highly energetic filler materials may be added to the nitramine(s) of Component B, the non-nitramine component(s) providing up to 25 per cent by weight of Component B. Examples of suitable known highly energetic materials include picrite (nitroguanidine), TAGN, aromatic nitramines such as tetryl, ethylene dinitramine, and nitrate esters such as nitroglycerine (glycerol trinitrate), butane triol trinitrate or pentaerythrital tetranitrate.

Various known additives may be added to the compositions according to the present invention comprising Components A, B and C as specified above. Preferably, the additive content comprises no more than 10 per cent by weight, desirably less than 5 per cent by weight, of the combined mixture when formed into a propellant.

The additive may for example comprise one or more stabilisers, e.g. carbamite or PNMA (para-nitro-methylmethoxyaniline); and/or one or more ballistic modifiers, e.g. carbon black or lead salts; and/or one or more flash suppressants, e.g. one or more sodium or potassium salts, e.g. sodium or potassium sulphate or bicarbonate.

Preferred compositions embodying the invention for use as gun propellants comprise:

______________________________________nitrocellulose 8 to 10 per cent by weightcellulose acetate butyrate 6 to 12 per cent by weightRDX 70 to 80 per cent by weightnitroaromatic plasticiser 5 to 10 per cent by weightcarbamite diethyl-diphenyl-urea 1 per cent by weightstabiliser______________________________________

In this composition, the nitroaromatic plasticiser is preferably selected from one of the following:

______________________________________(a) a mixture of dinitroethylbenzene and trinitroethylbenzene containing: dinitroethyl- 50-64 per cent by weight benzene trinitroethylbenzene 36-50 per cent by weight;(b) 2,4-dinitrotoluene;(c) 4,6-dinitro-o-cresol;(d) 2,4-dinitro-m-xylene;______________________________________

Compositions according to the present invention may be processed into products such as propellants by techniques which are known to those skilled in the art. The plasticiser comprising Component C is added to and absorbed by the polymer of Component A to swell and soften the polymer. If Component C includes a solid it may be melted and then added to Component A or added in a suitable solvent, e.g. acetone or ethyl acetate. Component B, preferably in a paste with an organic solvent, is blended with a mixture of Components A and C in a suitable kneader to form a homogeneous composition. Eventually, the composition produced is pressed or extruded in the form of a dough-like material through suitably shaped extrusion dies. The extrusion may be carried out using a co-rotating twin screw extrusion machine.

The product obtained by extrusion of compositions according to the present invention may be obtained in any suitable form. For example, where the product is a gun propellant, it may be obtained in the form of sticks or granules of known shape. Sticks are usually formed by cutting to a suitable length rods or strands extruded through suitable dies giving a shape including a longitudinal slot. Granules are usually similarly formed by cutting to much shorter lengths rods or sticks obtained by extrusion. Normally such granules have small holes, e.g. seven holes running lengthwise therethrough to provide suitable burning surfaces.

An important feature of certain propellant products is the web size of the product shape or configuration. This parameter, well known to those skilled in the propellants art, is the minimum thickness of propellant to be burnt through from one surface to another. For example, for a propellant product having simple tube configuration, the web thickness is the outer to inner wall thickness of the cross-sectional annulus of the tube. Web sizes of propellant products incorporating compositions embodying the invention may vary over a range according to the specific application, e.g. from 0.5 mm to 4.0 mm, although the more desirable web sizes at the lower end of this range, e.g. from 0.5 mm to 2.0 mm, will generally be suitable for most applications because the compositions generally have a low burning rate.

Examples of compositions embodying the invention and their use in the production of propellant materials will now be described.

In the following examples the appropriate Components A, B and C (as defined above) are prepared by known methods. These components are then formed into propellant products in the following general way which is known per se. The solid components comprising Component A and any minor additives, e.g. stabiliser and/or flame suppressant, are loaded as a powder into an incorporator (blender) whose blades have previously been moistened with an organic solvent. The viscous liquid comprising Component C is added to a solvent and the mixture is poured into the incorporator to which further solvent is then added. The mixture is then incorporated together for 30 minutes after which further solvent is added and the mixture is subsequently further blended for 4 hours. Cold water is continuously run through the incorporator during blending.

After processing in the incorporator the mixture formed is dried in an oven at a temperature of typically 50.degree.-90.degree. C. for a period of several hours and subsequently pressed or extruded into strands of the required shape and web size which or cut into appropriate lengths as will be readily apparent to those skilled in the art.

Products embodying the present invention comprising compositions of the following components may be made in the manner described above. In the following compositions "Nitrocellulose" means nitrocellulose containing 12.6% by weight N.

__________________________________________________________________________ Percentage Ingredient by weight__________________________________________________________________________Composition 1Component A Cellulose acetate 20Component B RDX 71Component C 2,4-dinitrotoluene 8 Carbamite 1Compositions 2 to 75Component A Cellulose acetate 20Component B RDX 71Component C 2,4-dinitrotoluene 4 Compound X* 4 Carbamite 1Composition 76Component A Cellulose acetate butyrate 15 Nitrocellulose 5Component B RDX 71Component C1 9wherein Component C1 comprises:2,6-dinitrotoluene 10 pbw2,4-dinitrotoluene 45 pbw2,4,6-trinitrotoluene 45 pbw(where pbw = parts by weight)Composition 77Component A Cellulose acetate butyrate 15 Nitrocellulose 5Component B RDX 71Component C2 9wherein Component C2 comprises: 2,6-dinitrotoluene 2 pbw 2,4-dinitrotoluene 54 pbw 2,4,6-trinitrotoluene 44 pbwComposition 78Component A Cellulose acetate butyrate 15 Nitrocellulose 5Component B RDX 71Component C3 9wherein Component C3 comprises:2,6-dinitrotoluene 2 pbw2,4-dinitrotoluene 64 pbw2,4,6-trinitrotoluene 34 pbwComposition 79Component A Cellulose acetate butyrate 15 Nitrocellulose 5Component B RDX 71Component C4 9wherein Component C4 comprises:2,6-dinitro-1-ethylbenzene 10 pbw2,4-dinitro-1-ethylbenzene 45 pbw2,4,6-trinitro-1-ethylbenzene 45 pbwComposition 80Component A Cellulose acetate butyrate 15 Nitrocellulose 5Component B RDX 71Component C5 9wherein Component C5 comprises:2,6-dinitro-1-ethylbenzene 2 pbw2,4-dinitro-1-ethylbenzene 54 pbw2,4,6-trinitro-1-ethylbenzene 44 pbwComposition 81Component A Cellulose acetate butyrate 15 Nitrocellulose 5Component B RDX 71Component C6 9wherein Component C6 comprises:2,6-dinitro-1-ethylbenzene 2 pbw2,4-dinitro-1-ethylbenzene 64 pbw2,4,6-trinitro-1-ethylbenzene 34 pbwComposition 82Component A Cellulose acetate butyrate 15 Nitrocellulose 5Component B RDX 71Component C7 9wherein Component C7 comprises:1-isopropyl-2,6-dinitrobenzene 10 pbw1-isopropyl-2,4-dinitrobenzene 45 pbw1-isopropyl-3,4,6-trinitrobenzene 45 pbwComposition 83Component A Cellulose acetate butyrate 15 Nitrocellulose 5Component B RDX 71Component C8 9wherein Component C8 comprises:1-isopropyl-2,6-dinitrobenzene 2 pbw1-isopropyl-2,4-dinitrobenzene 54 pbw1-isopropyl-3,4,6-trinitrobenzene 44 pbwComposition 84Component A Cellulose acetate butyrate 15 Nitrocellulose 5Component B RDX 71Component C9 9wherein Component C9 comprises:1-isopropyl-2,6-dinitrobenzene 2 pbw1-isopropyl-2,4-dinitrobenzene 64 pbw1-isopropyl-3,4,6-trinitrobenzene 34 pbwComposition 85Component A Cellulose acetate butyrate 12 Nitrocellulose 8.2Component B RDX 73.8Component C6 5Component D Carbamite 1wherein Component C6 is as defined above.Composition 86Component A Cellulose acetate butyrate 12 Nitrocellulose 8.2Component B RDX 73.8Component C10 5Component D Carbamite 1wherein Component C10 comprises:2,6-dinitro-1-ethylbenzene 2 pbw2,4-dinitro-1-ethylbenzene 48 pbw2,4,6-trinitro-1-ethylbenzene 50 pbwComposition 87Component A Cellulose acetate butyrate 8 Nitrocellulose 10Component B RDX 72Component C10 9Component D Carbamite 1wherein Component C10 is as defined above.Composition 88Component A Cellulose acetate butyrate 6 Nitrocellulose 8Component B RDX 77Component C10 8.5Component D Carbamite 0.5wherein Component C10 is as defined above.Composition 89Component A Cellulose acetate butyrate 12 Nitrocellulose 8.2Component B RDX 73.8Component C 4,6-dinitro-o-cresol 5Component D Carbamite 1Composition 90Component A Cellulose acetate butyrate 12 Nitrocellulose 8.2Component B RDX 73.8Component C 2,4-dinitrotoluene 5Component D Carbamite 1Composition 91Component A Cellulose acetate butyrate 12 Nitrocellulose 8.2Component B RDX 73.8Component C 2,4-dinitro-m-xylene 5Component D Carbamite 1__________________________________________________________________________ *wherein X is successively 1 to 68 and 70 to 75 as listed above

Compositions 1 to 91 show energy levels which are in the approximate range of 1100-1300 Joules per gram. As noted above double base compositions generally show a lower ignition temperature and lower vulnerability at the same respective energy levels.

Examples of the properties of some of the above compositions are given in Table 1 as follows, wherein

E=propellant energy in KJ per Kg, T=propellant flame temperature in degrees Kelvin, d=density in grammes per cm.sup.3. TABLE 1______________________________________Properties of Examples of CompositionsCompositionNo. E T d______________________________________85 1178 3088 1.68986 1182 3143 1.68987 1216 3241 1.69188 1279 3453 1.70689 1170 3092 1.68690 1174 3123 1.67191 1168 3054 1.671______________________________________

Compositions 1 to 91 show ignition temperatures which are 20-30 degrees Celsius or more above those of known double base and triple base compositions of the same energy level.

For example, a composition comprising:

______________________________________nitroglycerine 32% by weightnitrocellulose 32% by weightpicrite 35% by weightcarbamite 1% by weight______________________________________ has a similar energy level to that of Composition 85, but its ignition temperature, 161.degree. C., is significantly lower than the ignition temperature, 226.degree. C., of Composition 85.

Claims

1. An energetic composition comprising the following components in the following relative properties:

Component A: from 5% to 25% by weight of a polymeric binder;

Component B: from 65% to 90% by weight of a highly energetic filler comprising at least one heteroalicyclic nitramine compound; and

Component C: from 1% to 15% by weight of a plasticiser which comprises two or more nitroaromatic compounds; the percentages by weight of Components A, B and C adding to 100%.

2. An energetic composition comprising the following components in the following relative proportions:

Component A: from 5% to 25% by weight of a polymeric binder;

Component B: from 65% to 90% by weight of a highly energetic filler comprising at least one heteralicyclic nitramine compound; and

Component C: from 1% to 15% by weight of a plasticizer which comprises:

a mixture of dinitroethylbenzene and trinitroethylbenzene containing:

dinitroethylbenzene 50 to 64 percent by weight

trinitroethylbenzene 36 to 50 percent by weight;

the percentages by weight of Components A, B and C adding to 100%.