Cast explosive composition

Patent metadata

Field	Value
Publication number	US-11001540-B2
Application number	US-201615742432-A
Country	US
Kind code	B2
Filing date	Jul 6, 2016
Priority date	Jul 7, 2015
Publication date	May 11, 2021
Grant date	May 11, 2021

Abstract

The invention relates to a cast explosive composition, particularly to a pre-cure castable explosive composition comprising an explosive material, a polymerisable binder, a microencapsulated cross linking reagent, said microencapsulated cross linking reagent, comprising a cross linking agent encapsulated in a microcapsule.

First claim

The invention claimed is:

1. A pre-cure castable explosive composition comprising an explosive material, a polymerisable binder, and a microencapsulated cross linking reagent, said microencapsulated cross linking reagent comprising a cross linking reagent encapsulated in a microcapsule, wherein the microcapsule includes a shell wall polymer comprising at least one labile linkage.

2. The composition according to claim 1 , wherein the polymerisable binder is selected, such that it will form with the cross linking reagent one or more of: a polyurethane, a cellulosic material, a cellulose acetate, a polyester, a polybutadiene, a polyethylene, a polyisobutylene, a PVA, a chlorinated rubber, an epoxy resin, a two-pack polyurethane system, an alkyd/melanine, a vinyl resin, an alkyd, a butadiene-styrene block copolymer, a polyNIMMO, a polyGLYN, a GAP, and 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 nitramines such as tetryl, 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 combinations thereof.

4. The composition according to claim 1 , wherein the microcapsule comprises a shell wall polymer selected from polyurethane, cellulose acetate, a polyester, a polybutadiene, a polyethylene, a polyisobutylene, PVA, chlorinated rubber, an epoxy resin, a two-pack polyurethane system, an alkyd/melanine, a vinyl resin, an alkyd, a butadiene-styrene block copolymer, polyNIMMO, polyGLYN, GAP, and blends, copolymers and/or combinations thereof.

5. The composition according to claim 4 , wherein the microcapsule shell wall polymer and the polymerisable binder are selected from substantially the same polymer.

6. The composition according to claim 1 , wherein the at least one labile linkage is a thermally labile linkage.

7. The composition according to claim 1 , wherein the labile linkage is selected from an acetal, a blocked isocyanate, and a diels alder linkage.

8. The composition according to claim 7 wherein the blocked isocyanate is selected from an aromatic heterocycle, a secondary amine, a substituted phenol, an oxime, and an amide.

9. An organic microcapsule shell suitable for encapsulating an organic payload reagent, wherein the microcapsule shell comprises a shell wall polymer, said shell wall polymer comprising at least one thermally labile linkage, wherein the thermally labile linkage comprises a blocked isocyanate of Formula X

wherein R and R 1 are terminal end groups of a monomer or polymer forming the backbone of the microcapsule wall, and B is a reversible blocking group selected from an amide or phenol.

10. A process for making a munition with a homogenous cross linked polymer bonded explosive composition, the process comprising:
forming an admixture of pre-cure castable explosive composition, said composition comprising an explosive material, a polymerisable binder, and a microencapsulated cross linking reagent, wherein the microencapsulated cross linking reagent comprises a cross linking reagent encapsulated in a microcapsule, wherein the microcapsule includes a shell wall polymer comprising at least one labile linkage;
filling the munition with the admixture; and
causing the microcapsule to release said cross linking reagent.

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

12. The process according to claim 10 , wherein the at least one labile linkage includes a thermally labile linkage.

13. The process according to claim 10 , wherein causing the microcapsule to release said cross linking includes applying at least one chemical stimulus and/or physical stimulus.

14. A munition comprising a cured polymer bonded explosive composition and ruptured microcapsules.

15. The composition according to claim 4 , wherein the shell wall polymer comprises polyurethane, the explosive material comprises RDX, and the polymerizable binder comprises HTPB.

16. The composition according to claim 15 , wherein the at least one labile linkage includes a thermally labile linkage.

17. The composition according to claim 16 , wherein the thermally labile linkage comprises a blocked isocyanate of Formula X

wherein R and R 1 are terminal end groups of a monomer or polymer forming the backbone of the microcapsule wall, and B is a reversible blocking group oxime.

18. The composition according to claim 17 , wherein at least one of R and R1 comprises a polyurethane.

19. The composition according to claim 18 , wherein the cross linking reagent is a diisocyanate.

20. The composition according to claim 1 , wherein thermal release of the labile linkage occurs at a temperature from 50° C. to 150° C., wherein the temperature is below an ignition temperature of the explosive material.

Assignees

• Bae Systems Plc

Inventors

• Stephens Rebecca Elizabeth
• Arthur Richard
• Hayes Wayne Cord
• Budd Michael

Classifications

• B01J13/14

  Polymerisation; cross-linking · CPC title

• C06B21/0058 Primary

  by casting a curable composition, e.g. of the plastisol type · CPC title

• C06B45/10 Primary

  the organic component containing a resin · CPC title