PBX composition

Abstract

The invention relates to a cast explosive composition. There is provided a precure castable explosive composition comprising an explosive material, a polymerisable binder, said cross linking reagent comprising at least two reactive groups each of which is protected by a labile blocking group. ##STR00001##

Claims

1. A precure castable explosive composition comprising: an explosive material; a polymerisable binder; and a diisocyanate comprising isocyanate reactive groups blocked by labile blocking groups B, at least one of the labile blocking groups B being (O—N═CR.sup.9R.sup.10), wherein R.sup.9 and R.sup.10 are independently selected from an alkyl, an alkenyl, a branched chain alkyl, a branched chain aryl, or a phenyl, and wherein at least one of R.sup.9 or R.sup.10 is a branched chain alkyl, a branched chain aryl, or a phenyl.

2. The composition according to claim 1, wherein the polymerisable binder is selected, such that it will form a polyurethane, cellulosic material, polyester, polybutadiene, polyethylene, polyisobutylene, PVA, chlorinated rubber, epoxy resin, a two-pack polyurethane system, alkyd/melanine, vinyl resin, alkyd, butadiene-styrene block copolymer, polyNIMMO, polyGLYN, GAP, or a blend, copolymer and/or combination thereof.

3. The composition according to claim 1, wherein the explosive material is selected from RDX, HMX, FOX-7, TATND, HNS, TATB, NTO, HNIW, GUDN, picrite, aromatic nitramine, ethylene dinitramine, nitroglycerine, butane triol trinitrate, pentaerythritol tetranitrate, DNAN trinitrotoluene, inorganic oxidiser, ADN, ammonium perchlorate, energetic alkali metal salt, energetic alkaline earth metal salt, and a combination thereof.

4. The composition according to claim 1, wherein the labile blocking groups B comprise at least one sterically hindered branched chain hydrocarbyl group.

5. The composition according to claim 1, wherein the polymerisable binder and the diisocyanate are partially reacted together to provide a partially polymerised binder-cross linking reagent.

6. The composition according to claim 1, wherein the polymerisable binder is selected, such that it will form polyurethane.

7. The composition according to claim 1, wherein one of the labile blocking groups B is NHR.sup.2R.sup.3, wherein R.sup.2 and R.sup.3 are alkyl, alkenyl, branched-chain alkyl, C(O)R.sup.12, aryl, phenyl, or together form a heterocycle and R.sup.12 is alkyl, alkenyl, branched chain alkyl aryl, phenyl, or R.sup.2 and R.sup.3 together form a lactam.

8. The composition according to claim 1, wherein a defoaming reagent is present in the range of from 0.01-2 wt %.

9. A batch process for filling a munition with a cross linked polymer bonded explosive composition, the process comprising: forming an admixture of precure castable explosive composition, comprising an explosive material, a polymerisable binder, and a diisocyanate comprising at least two reactive groups blocked by labile blocking groups B, at least one of the labile blocking groups B being (O—N═CR.sup.9R.sup.10), wherein R.sup.9 and R.sup.10 are independently selected from an alkyl, an alkenyl, a branched chain alkyl, a branched chain aryl, or a phenyl, and wherein at least one of R.sup.9 or R.sup.10 is a branched chain alkyl, a branched chain aryl, or a phenyl; filling the munition; and causing the removal of the blocking group to furnish said cross linking reagent.

10. The process according to claim 9, further comprising causing the cure of said polymerisable binder to form a polymer bonded cast explosive composition.

11. The process according to claim 9, wherein one of the blocking groups B is NHR.sup.2R.sup.3, wherein R.sup.2 and R.sup.3 are alkyl, alkenyl, branched-chain alkyl, C(O)R.sup.12, aryl, phenyl, or together form a heterocycle and R.sup.12 is alkyl, alkenyl, branched chain alkyl aryl, phenyl, or R.sup.2 and R.sup.3 together form a lactam.

12. A cured explosive product cured from the precure castable explosive composition of claim 1.

13. A munition comprising the cured explosive product of claim 12.

14. The composition according to claim 2 wherein the polymerisable binder comprises cellulosic material, and the cellulosic material is cellulose acetate.

15. The composition according to claim 2, wherein the explosive material is selected from RDX, HMX, FOX-7, TATND, HNS, TATB, NTO, HNIW, GUDN, picrite, aromatic nitramine, ethylene dinitramine, nitroglycerine, butane triol trinitrate, pentaerythritol tetranitrate, DNAN trinitrotoluene, inorganic oxidiser, ADN, ammonium perchlorate, energetic alkali metal salt, energetic alkaline earth metal salt, and a combination thereof.

16. The composition according to claim 3, wherein the explosive material comprises an aromatic nitramine, and the aromatic nitramine is tetryl.

17. The composition according to claim 3, wherein the explosive material comprises an inorganic oxidiser, and the inorganic oxidiser is ammonium nitrate.

Description

(1) An embodiment of the invention will now be described by way of example only and with reference to the accompanying drawings of which:—

(2) FIG. 1 shows a schematic of the fill process

(3) Turning to FIG. 1 there is a general scheme 1, for filling a munition 6. The premix formulation 2, is a mixture of the explosive, HTBP polymerisable binder and other processing aids, and optionally a catalyst. The premix formulation 2 is agitated such as by a stirrer 3. A blocked cross linking reagent 4, (either as a solid or dissolved in a minimal aliquot of solvent), is added to the premix to form the precure formulation 5. The blocked cross linking reagent 4 may be a diisocyanate such as IPDI. The resultant precure admixture 5 is thoroughly mixed and is transferred to a munition 6 or mould (not shown) for later insertion into a munition. The munition 6 when filled with the precure 5 may then be exposed to an external stimuli, such as heat, which removes the thermally labile blocking group on the blocked cross linking reagent 4, furnishing the cross linking reagent. The cross linking reagent and HTPB polymerisable binder may then polymerise and form a polymer bonded explosive 7.

(4) It should be appreciated that the compositions of the invention are capable of being incorporated in the form of a variety of embodiments, only a few of which have been illustrated and described above.