KDNP – A LEAD STYPHNATE REPLACEMENT

Lead Styphnate

Environmentally friendly KDNP is conveniently prepared from inexpensive reactants and may be easily recrystallized to a particle size appropriate for use in a variety of systems. It may be tailored for use as either a (small particle) component of a bridgewire slurry or a (large particle) constituent of a stab primer.

Lead styphnate (LS) is a primary explosive widely used in ordnance systems as a component of initiation trains. These applications include non-corrosive percussion primers, stab initiated devices, bridgewire initiated compositions, and detonators. For example, LS based compositions are widely used in military percussion primers such as the PVU-12/A and stab primers such as the MK102. It is used in nearly all U.S. commercial primer applications as well. In addition, LS is widely used in military hot-wire application (electric initiators) wherein the LS accepts the transfer of heat from a bridgewire, deflagrates, and initiates energetic trains/outputs. Examples of these uses include TOW missile initiators and the CCU-63 impulse cartridge. Lead styphnate has been widely used in ordnance systems for many years. It is a reliable explosive material and because it has been studied extensively, properties and manufacturing processes are well defined. However, despite being a useful energetic material, LS contains lead, a toxic heavy metal that is released to the environment during production and use. Environmental health and safety regulations on lead containing materials are quite extensive and are likely to increase in severity in the future, along with compliance costs. The manufacture, use, demilitarization and disposal of LS (and ordnance containing them) are deeply impacted by these regulations, and lead-free alternatives to LS have been sought for a number of years.

No Toxic or Environmentally Undesirable Elements

Pacific Scientific Energetic Materials Company (PacSci EMC) in Chandler, AZ, in conjunction with chemists at NSWC-IH, has been involved since 1999 in a program to develop existing or new materials which would serve as a drop-in replacement for LS and which incorporate no toxic or environmentally undesirable elements. We investigated a wide variety of chemically distinct materials in order to find a green replacement for LS with suitable sensitivity and output characteristics and selected 4,6-dinitro-7-hydroxy benzofuroxan, potassium salt (KDNP). KDNP completed 8020.5C evaluation testing in 2007 and, based on the results (NSWC Contract #N00174-06-C-0079), Naval Sea Systems Command qualified KDNP as a primary explosive in accordance with the requirements of NAVSEAINST 8020.5C and identified it as a safe and suitable for service use, and qualified for weapons development.

KDNP Performance and Compatibility

In addition to qualification testing, KDNP has been successfully evaluated against LS for performance in a variety of applications such as the CCU-63, TOW missile initiator and PVU-12/A percussion primer. KDNP has compatibility which is equal to or greater than LS with a variety of ordnance materials and has substantially greater output on a weight basis in pressure-time (closed bomb) testing. Significantly, KDNP may be conveniently recrystallized to a particle size appropriate for use in a variety of systems so may be tailored for use as either a (small particle) component of a bridgewire slurry or a (large particle) constituent of a stab primer.

References

“KDNP – A Lead Free Replacement for Lead Styphnate”, J. W. Fronabarger, M. D. Williams, W. B. Sanborn, D. A. Parrish and M. Bichay, Propellants, Explosives, Pyrotechnics, 36, 459 (2011).

U.S. Patents: 8,062,443, 8,216,401.