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 cross-linking reagent having at least a first reactive group protected by a first labile blocking group and a second reactive group protected by a second labile blocking group, the first and second labile blocking groups independently selected from (i) NHR.sup.2R.sup.3, wherein R.sup.2 and R.sup.3 are an alkyl, an alkenyl, a branched-chain alkyl, C(O)R.sup.12, an aryl, a phenyl, or together form a heterocycle, wherein R.sup.12 is an alkyl, an alkenyl, a branched chain alkyl, a branched chain aryl, a phenyl, or R.sup.2 and R.sup.3 together form a lactam; or (ii) 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, an 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 precure castable explosive composition of claim 1, wherein the cross-linking reagent comprises a polyisocyanate.

3. The precure castable explosive composition of claim 2, wherein the cross-linking reagent comprises a diisocyanate.

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

5. The composition according to claim 4, wherein the polymerisable binder is selected, such that it will form polyurethane.

6. The composition according to claim 4, wherein the polymerisable binder comprises polybutadiene.

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

8. The composition according to claim 7, further comprising a metal powder selected from aluminum, magnesium, tungsten, alloys of these metals, or a combination thereof.

9. The composition according to claim 1, wherein the polymerisable binder and the cross linking reagent are partially reacted together to provide a partially polymerised binder-cross linking reagent, wherein at least one of the first and second reactive groups of the cross linking reagent is protected by the respective first or second labile blocking group.

10. The composition according to claim 1, further comprising a defoaming reagent present in the range of from 0.01-2 wt %.

11. A precure castable explosive composition comprising: an explosive material; a polymerisable binder; and a polyisocyanate comprising a first reactive group protected by a first labile blocking group and a second reactive group protected by a second labile blocking group, the first and second labile blocking groups independently selected from (i) NHR.sup.2R.sup.3, wherein R.sup.2 and R.sup.3 are an alkyl, an alkenyl, a branched-chain alkyl, C(O)R.sup.12, an aryl, a phenyl, or together form a heterocycle, wherein R.sup.12 is an alkyl, an alkenyl, a branched chain alkyl, a branched chain aryl, a phenyl, or R.sup.2 and R.sup.3 together form a lactam; or (ii) 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, an 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.

12. The composition according to claim 11, wherein at least one of the first and second labile blocking groups comprises at least one sterically hindered branched chain hydrocarbyl group.

13. The composition according to claim 11, wherein the explosive material is selected from RDX, HMX, FOX-7, TATND, HNS, TATB, NTO, HNIW, GUDN, picrite, an aromatic nitramine, ethylene dinitramine, nitroglycerine, butane triol trinitrate, pentaerythritol tetranitrate, DNAN trinitrotoluene, an inorganic oxidiser, ADN, ammonium perchlorate, an energetic alkali metal salt, an energetic alkaline earth metal salt, and a combination thereof.

14. The composition according to claim 11, wherein the explosive material comprises an aromatic nitramine, and the aromatic nitramine is tetryl.

15. The composition according to claim 11, wherein the explosive material comprises ammonium nitrate.

16. The composition according to claim 11, wherein the polymerisable binder and the polyisocyantate are partially reacted together such that the precure castable explosive composition includes partially polymerised binder-polyisocyanate, and wherein at least one of the first and second reactive groups of the cross linking reagent is protected by the respective first or second labile blocking group.

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.