This invention relates to an explosive combination. In a particular aspect this invention relates to a primer adapted to initiating detonation of nitromethane by strong shock.
Nitromethane is a very stable liquid but it can be detonated under extraordinary conditions. When it does detonate, it is extremely powerful and is useful in many special applications. However the difficulty in initiating detonation has long been a problem, often requiring expensive primers and boosters.
It is known from Minnick, U.S. Pat. No. 3,338,165 that insoluble air-entrapping materials, such as resin balloons, can be uniformly suspended in gelled nitromethane and thereby render it sensitive to detonation by strong shock. It is necessary to gel the nitromethane because otherwise the air-entrapping material will segregate whereupon the composition loses its sensitivity to strong shock and does not detonate when the initiator is fired.
The compositions disclosed by Minnick are satisfactory when freshly prepared but they suffer from several disadvantages. For field use, it is inconvenient, if not impossible, to gel the nitromethane at the site of use and uniformly mix in the air-entrapping material. It is possible to prepare the composition ahead of time and transport it to the site, but it has been found that the composition loses its sensitivity on aging, possibly due to displacement of the entrapped air by nitromethane. Also it is risky to transport a shock-sensitive explosive mixture under field conditions. Furthermore, once the composition has been prepared, it cannot be easily desensitized if it is not used promptly.
Accordingly, there is a need for an improved method for detonating nitromethane.