Chain-extended poly(bis-azidomethyloxetane), and combustible cartridge cases and ammunition comprising the same

• US 20010047072A1
• Filed: 04/24/2001
• Published: 11/29/2001
• Est. Priority Date: 05/02/2000
• Status: Active Grant

• Current Assignee: Orbital ATK Inc.
• Original Assignee: Alliant Techsystems Incorporated (Northrop Grumman Corporation)
• Inventors: Akester, Jeffrey D., Widener, Jeff F., Edwards, William W., Sanderson, Andrew J., Braithwaite, Paul C.
• Granted Patent: US 6,600,002 B2
• Time in Patent Office: Days
• US Class Current: 528/78
• CPC Class Codes: C08G 18/10 Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
• CPC Class Codes: C08G 18/3206 aliphatic
• CPC Class Codes: C08G 18/5021 having nitrogen
• CPC Class Codes: F42B 30/12 with provision for additional propulsive charges, or for varying the length
• CPC Class Codes: F42B 5/181 consisting of a combustible casing wall and a metal base; Connectors therefor
• CPC Class Codes: F42B 5/192 Cartridge cases characterised by the material of the casing wall cartridge bags F42B5/38

Abstract

A combustible cartridge case is provided that includes at least one energetic thermoplastic homopolymer or copolymer derived from, at least in part, poly(bis-azidomethyloxetane) prepolymer blocks terminated with isocyanate-reactive groups, such as hydroxyl groups. Chain linking of the prepolymer blocks is performed with diisocyanates for end-capping the prepolymer blocks, and a difunctional linking compound for linking the end-capped prepolymer blocks. The energetic thermoplastic is preferably capable of being pressed, extruded, rotational molded, injection loaded, or otherwise shaped into a desired configuration. Also provided is a chain-extended poly(bis-azidomethyloxetane) homopolymer derived from bis-azidomethyloxetane prepolymer blocks, which are terminated with isocyanate-reactive groups and chain extended with at least one diisocyanate end-capping compound and at least one difunctional linking compound.

Claims

1. Chain-extended poly(bis-azidomethyloxetane) homopolymer comprising poly(bis-azidomethyloxetane) prepolymer blocks terminated with isocyanate-reactive groups and chain extended with at least one diisocyanate end-capping compound and at least one linking compound comprising two functional groups which are reactive with isocyanate moieties of said diisocyanate end-capping compound.

2. The chain-extended poly(bis-azidomethyloxetane) homopolymer of

claim 1

, wherein the isocyanate-reactive groups are hydroxyl groups.

3. The chain-extended poly(bis-azidomethyloxetane) homopolymer of

claim 1

, wherein the linking compound is a diol.

4. The chain-extended poly(bis-azidomethyloxetane) homopolymer of

claim 3

, wherein the diol comprises butane diol.

5. The chain-extended poly(bis-azidomethyloxetane) homopolymer of

claim 1

, wherein the diisoyanate end-capping compound comprises 2,4-toluene diisocyanate.

6. A combustible ammunition cartridge case configured with a chamber for receiving a propellant and comprising at least one energetic thermoplastic binder, said energetic thermoplastic binder comprising at least one member selected from the group consisting of a chain-extended poly(bis-azidomethyloxetane) homopolymer and a chain-extended copolymer or terpolymer, wherein:

(a) said chain-extended poly(bis-azidomethyloxetane) homopolymer comprises poly(bis-azidomethyloxetane) prepolymer blocks terminated with isocyanate-reactive groups and chain extended with at least one diisocyanate end-capping compound and at least one linking compound comprising two functional groups which are reactive with isocyanate moieties of said diisocyanate end-capping compound; and

(b) said chain-extended copolymer or terpolymer comprises poly(bis-azidomethyloxetane) prepolymer blocks and one or more additional co-polymerizable prepolymer blocks, said poly(bis-azidomethyloxetane) prepolymer blocks and said additional co-polymerizable prepolymer blocks being terminated with isocyanate-reactive groups and chain extended with each other with at least one diisocyanate end-capping compound and at least one linking compound comprising two functional groups which are reactive with isocyanate moieties of said diisocyanate end-capping compound.

7. The combustible ammunition cartridge case of

claim 6

, wherein said energetic thermoplastic binder comprises said chain-extended poly(bis-azidomethyloxetane) homopolymer.

8. The combustible ammunition cartridge case of

claim 6

, wherein said energetic thermoplastic binder comprises said chain-extended copolymer or terpolymer, and further wherein said additional co-polymerizable prepolymer blocks are derived from at least one oxetane monomer.

9. The combustible ammunition cartridge case of

claim 6

, wherein said additional co-polymerizable prepolymer blocks are derived from at least one oxetane monomer selected from the group consisting of 3-azidomethyl-3-methyloxetane (AMMO) and 3-nitratomethyl-3-methyloxetane (NMMO).

10. The combustible ammunition cartridge case of

claim 6

, wherein said energetic thermoplastic binder comprises said chain-extended copolymer or terpolymer, and further wherein said additional co-polymerizable prepolymer blocks comprise at least one oxirane prepolymer.

11. The combustible ammunition cartridge case of

claim 10

, wherein said oxirane prepolymer comprises at least one member selected from the group consisting of difunctional glycidyl azide polymers and poly(glycidyl nitrate).

12. The combustible ammunition cartridge case of

claim 6

, further comprising polyethylene.

13. The combustible ammunition cartridge case of

claim 6

, further comprising at least one energetic filler selected from the group consisting of cyclotetramethylene tetranitramine (HMX), cyclotrimethylene trinitramine (RDX), 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazatetracyclo[5.5.0.0^5,9.0^3,11]-dodecane (CL-20), 4,10-dinitro-2,6,8,12-tetraoxa-4,10-diazatetracyclo[5.5.0.0^5,9,0^3,11]dodecane (TEX), and nitroguanidine (NQ).

14. The combustible ammunition cartridge case of

claim 6

, further comprising at least one oxidizer selected from the group consisting of ammonium perchlorate (AP), ammonium nitrate (AN), hydroxylammonium nitrate (HAN), ammonium dinitramide (ADN), potassium nitrate (KN), potassium dinitramide (KDN), and potassium perchlorate (KP).

15. The combustible ammunition cartridge case of

claim 6

, wherein said binder constitutes from about 70% by weight to about 100% by weight of said combustible ammunition cartridge shell.

16. The combustible ammunition cartridge case of

claim 6

, wherein said poly(bis-azidomethyloxetane) prepolymer blocks constitute from about 50% by weight to about 100% by weight of said binder.

17. Ammunition comprising:

a combustible ammunition cartridge case configured with a chamber and comprising an energetic composition;

propellant received within said chamber of said combustible ammunition cartridge case; and

a projectile in operative relation with the combustible ammunition cartridge case to receive a propulsive force upon ignition of said combustible ammunition cartridge case and said propellant,

said energetic composition comprising at least one energetic thermoplastic binder, said energetic thermoplastic binder comprising at least one member selected from the group consisting of a chain-extended poly(bis-azidomethyloxetane) homopolymer and a chain-extended copolymer or terpolymer, wherein;

(a) said chain-extended poly(bis-azidomethyloxetane) homopolymer is derived from poly(bis-azidomethyloxetane) prepolymer blocks terminated with isocyanate-reactive groups and chain extended with at least one diisocyanate end-capping compound and at least one linking compound comprising two functional groups which are reactive with isocyanate moieties of said diisocyanate end-capping compound; and

(b) said chain-extended copolymer or terpolymer is derived from poly(bis-azidomethyloxetane) prepolymer blocks and one or more additional co-polymerizable prepolymer blocks, said poly(bis-azidomethyloxetane) prepolymer blocks and said additional co-polymerizable prepolymer blocks being terminated with isocyanate-reactive groups and chain extended with each other with at least one diisocyanate end-capping compound and at least one linking compound comprising two functional groups which are reactive with isocyanate moieties of said diisocyanate end-capping compound.

18. The ammunition of

claim 17

, wherein said ammunition is a mortar round.

19. The ammunition of

claim 17

, wherein said ammunition comprises direct-fire or indirect-fire ammunition.

20. The ammunition of

claim 17

, wherein said energetic thermoplastic binder comprises said chain-extended poly(bis-azidomethyloxetane) homopolymer.

21. The ammunition of

claim 17

, wherein said energetic thermoplastic binder comprises said chain-extended copolymer or terpolymer, and further wherein said additional co-polymerizable prepolymer blocks comprise at least one oxetane prepolymer.

22. The ammunition of

claim 21

, wherein said additional co-polymerizable prepolymer blocks are derived from at least one oxetane monomer selected from the group consisting of 3-azidomethyl-3-methyloxetane (AMMO) and 3-nitratomethyl-3-methyloxetane (NMMO).

23. The ammunition of

claim 17

, wherein said energetic thermoplastic binder comprises said chain-extended copolymer or terpolymer, and further wherein said additional co-polymerizable prepolymer blocks comprise at least one oxirane prepolymer.

24. The ammunition of

claim 23

, wherein said oxirane prepolymer comprises at least one member selected from the group consisting of difunctional glycidyl azide polymers and poly(glycidyl nitrate).

25. The ammunition of

claim 17

, further comprising polyethylene.

26. The ammunition of

claim 17

, further comprising at least one energetic filler selected from the group consisting of cyclotetramethylene tetranitramine (HMX), cyclotrimethylene trinitramine (RDX), 2,4,6,8,10,12 hexanitro 2,4,6,8,10,12 hexaazatetracyclo[5.5.0.0^5.9.0^3,11]-dodecane (CL-20), 4,10-dinitro-2,6,8,12-tetraoxa -4,10-diazatetracyclo[5.5.0.0^5,9,0^3,11]dodecane (TEX), and nitroguanidine (NQ).

27. The ammunition of

claim 17

, further comprising at least one oxidizer selected from the group consisting of ammonium perchlorate (AP), ammonium nitrate (AN), hydroxylammonium nitrate (HAN), ammonium dinitramide (ADN), potassium nitrate (KN), potassium dinitramide (KDN), and potassium perchlorate (KP).

28. The ammunition of

claim 17

, wherein said binder constitutes from about 70% by weight to about 100% by weight of said combustible ammunition cartridge shell.

29. The ammunition of

claim 17

, wherein said poly(bis-azidomethyloxetane) prepolymer blocks constitute from about 50% by weight to about 100% by weight of said binder.