High performance explosive containing CL-20

Details High performance explosive containing CL-20 High performance explosive containing CL-20

1998-10-06

2001-04-10

Miller, Edward A. (Department: 3641)

Explosive and thermic compositions or charges

Structure or arrangement of component or product

Solid particles dispersed in solid solution or matrix

C149S092000

Reexamination Certificate

active

06214137

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to high performance explosive compositions that are pressable or extrudable, and to devices and apparatuses using the explosive compositions as an explosive ingredient for high performance, low sensitivity explosive applications. More specifically, this invention relates to high performance explosive compositions comprising CL-20, energetic plasticizers, and high molecular weight non-energetic polymeric binders.
2. Description of the Related Art
Among the litany of high performance explosives that have been used in ordnance and other high impact applications, a relatively new explosive known as CL-20 has been recognized for its superior energy levels that far surpass those of most conventional explosives. CL-20, is referred to commonly as (2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazatetracyclo[5.5.0.0
5,9
.0
3,11
]-dodecane and 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane.
Examples of explosive formulations containing CL-20 as the primary explosive component are disclosed in both U.S. Pat. No. 5,587,553 to Braithwaite et al. and U.S. Pat. No. 5,712,511 to Chan et al. As touched upon in the Chan et al. '511 patent, which relates to explosive compositions for deformable-type warheads and directional ordnances, CL-20 is extremely sensitive to physical impact. Indeed, CL-20 has been associated with high electrical and thermal sensitivities as well. The highly sensitive nature of CL-20 may lead to premature detonation in ordnance applications. The Chan et al. patent apparently compensates for the high sensitivity of CL-20 by incorporating it into high energy shock-insensitive explosive compositions comprised of a relatively low concentration of CL-20, e.g., from about 35 wt % to about 45 wt %.
In contrast, the Braithwaite et al. patent seeks to improve the high performance of the CL-20 explosive by using it in high concentrations and in combination with high molecular weight liquid energetic polymers, especially chain-extended polyglycidyl nitrate (PGN). It has also been known to use CL-20 in combination with other polymers. One such combination commonly known as LX-19 combines CL-20 with ESTANE (C
5.14
H
7.5
N
0.187
O
1.76
). The performance characteristics, e.g., energy levels, exhibited by LX-19 are generally considered to be excellent. However, the impact, electrical, and thermal sensitivities associated with LX-19 and other formulations using CL-20 in combination with energetic binders are considered to be too high for some applications.
It would, therefore, be a significant advancement in the art to provide a plastic bonded explosive formulation that contains a sufficient amount of CL-20 to exhibit equal or better high energy performance than LX-19, yet which has sufficiently low impact, electrical, and thermal sensitivities to permit the formulation to be used for a variety of applications without an unacceptable risk of unintentional or premature detonation.
SUMMARY OF THE INVENTION
It is, therefore, an object of this invention to provide a pressable or extrudable high performance explosive formulation that addresses the aforementioned problems associated with the related art and realizes the advancement expressed above.
In accordance with the principles of this invention, these and other objects are attained by providing an explosive formulation prepared from high molecular weight polymers precipitated onto high performance explosives comprising CL-20. Generally, this formulation includes about 85 wt % to about 95 wt % CL-20, and about 5 wt % to about 15 wt % of a binder system. The binder system comprises at least one non-energetic polymeric binder, preferably cellulose acetate butyrate (CAB), and at least one energetic plasticizer, preferably bis-dinitropropyl acetal/bis-dinitropropyl formal (BDNPA/F). The weight ratio of bis-dinitropropyl acetal to bis-dinitropropyl formal in the BDNPA/F should be selected to provide the plasticizer in a substantially liquid and free flowing state. Preferably, this weight ratio is between about 45:55 and about 55:45, and more preferably about 50:50.
According to a preferred embodiment of the invention, the formulation includes about 94 wt % CL-20, about 2 wt % to about 2.8 wt % non-energetic binder, and about 3.2 wt % to about 4 wt % energetic plasticizer. More preferably, the formulation includes about 94 wt % CL-20, about 2.4 wt % non-energetic binder, and about 3.6 wt % energetic plasticizer.
This invention also relates to articles comprising the above-discussed formulations. The formulation is preferably sufficiently pressable or extrudable to permit it to be formed into grains or billets, for example, suitable for ordnance and similar applications. The principles of the present invention outlined above are applicable to a variety of explosive articles, but have particular applicability to pressed or injection loaded ordnances such as grenades, land mines, missile warheads, and demolition explosives.
These and other objects, features, and advantages of the present invention will become apparent from the accompanying drawing and following detailed description which illustrate and explain, by way of example, the principles of the present invention.


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Wardle et al., “Synthesis of the caged nitramine HNIW (CL-20)”, p. 301, XP 000664704 Chemical Abstracts, vol. 125, No. 14, Sep. 30, 1996.

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