US2255653A - Sensitized explosive - Google Patents

Description

I tion and desensitization.

Patented Sept. 9, 1941 SENSITIZED EXPLOSIVE John w. Dawson and William M. Dehn, Seattle, Wash.

No Drawing. Application October 31, 1938, Serial No. 237.984

4- Claims.

Our invention relates-generally to the process of sensitizing potentially explosive compositions, and particularly to the use of concentrations of organic polyhalogen compounds for such purposes. The prior art discloses that certain organic halogen compounds have been used in explosives for purposes of freezing-point depression, dispersion of toxic gases, water proofing, demoli- We have found that certain explosives, requiring nitro-glycerine, nitrated aromatic hydrocarbons, aluminum dust or other sensitiz'ers, for uniform detonating eilects,

can advantageously contain organic halogen compounds instead of any of said sensltizers. For example, a main explosive charge, such as can be manufactured by impregnation of wood meal with sodium nitrate (U. S. Patent 1,819,456) cannot be detonated by a. No. 6 cap; however, when carbon tetrachloride is added in certain relatively small percentages, the cap will explode the mixture. Likewise, other organic halogen compounds can be used. to sensitize the impregnated mixture. Furthermore, we have found v that other explosives, requiring sensitizing components, can be detonated by a No. 6 cap provided relatively small percentages of organic halogen compounds, comprising a critical concentration, can be used to sensitize. Thisdiscovery is apparently contradicted by the U. S. Patent 1,336,661, wherein carbon tetrachloride and stearin are recited as diluents and desensitizers I for nitroglycerine. Such desensitization isunderstandable when it is remembered that nitroglycerine is a detonating explosive and these diluents, per se, are not.

We have found that polyhalogen organic compounds containing more than two halogen atoms become detonating when the main explosive composition contains an excess of oxygen and available metallic atoms, whereby either intermediate,

highly-detonating compounds such as halogenated acetylenes, nitrogen halides, etc. are formed or because high heats of formation of metallic low 220 C., such as the polychlorinated derivatives of benzene and naphthalene. However, we do not limit our claims to these, because certain halogen compounds of the other groups also are sensitizers of certain explosives mixtures when blended so as to yield by detonation, the metallic halides.

Substitution of nitroglycerine in detonating compositions by effective sensitizing concentration of halogen-organic compounds avoids the hazardous, freezing and toxic properties of the former. Substitution of a part of the nitroglycerine, in detonating compositions, by halogen organic compounds reduces these properties and also lowers the cost of manufacture.

Biihringer and Stihne (D. R. P. 197,308, Nov. 20, 1906) depressed the freezing pointof nitroglycerine in detonating compositions by addition of chlorhydrin. Other workers in the art used mono-chlor and di-chlor glyceryl nitrates for this purpose. Nowhere in the literature is there any disclosure or recognition. of what we have discovered, to-wit, the sensitizing effects of organic chlorine compounds. Whenever, in the prior art, polyhalogen compounds had been used,

other effects than sensitization were sought and achieved, namely waterproofing and dispersion of toxic halogen compounds-and no sensitization, as revealed in this specification, was ever indicated or ecognized.

Examples of our new process and product are given below:

A mass of 8 parts of finely comminuted plant tissue impregnated'with 72 parts of sodium nitrate is dried and screened for granulation. This is intimately mixed with 10v parts of sulphur, 4 parts of liquid or finely puverized solid organic halogen compound.

A mass of 8 parts of mesh wood meal is fir impregnated with 10 parts of sulphur by mechanically mixing and heating substantially at -140" C. The resulting mass is then impregnated with an aqueous solution of 72 parts of sodium nitrate boiling at 120 C. This mass is then cooled, dried and screened. Finally 8 parts of pulverized poly-. halogen compounds are added and intimately intermixed. The polyhalogen compound. can advantageously be dissolved in carbon tetrachloride for the purpose of dispersion throughout themain mass. The partial or complete evaporation of the carbon tetrachloride is promoted in the subconcentration of it can contribute directly to I solids whose melting points are substantially be- 55 sensitization of the finished explosive.

A mass of 8 parts of finely divided combustible matter is first impregnated with 10 parts of sulphur: and 4 parts of organic halogen compounds, by the process of mechanically mixing and heating substantially at 120-l40 C. This mass is then impregnated with an aqueous solution of 72 parts of a metallic nitrate. After cooling, drying and screening, this explosive is a gray inodorous mas.

A mass of 9.5 parts of starch, 2 parts of sulphur, 5 parts of a mixture of aromatic polyhalogen compounds, 67.5 parts of ammonium nitrate, 16 parts of a metallic nitrate and 6 to 10 parts of water is heated to 100 C. for the time necessary for gelatinization of the starch. It is then subjected to reduced pressure for the purpose of rendering the entire mam porous: the cooled mass is then easily granulated and dried.

A mass of 9.5 parts of starch, 2 parts of sulphur, 5 parts of a mixture of aromatic polyhalogen compounds, 67.5 parts of ammonium nitrate, 16 parts of potassium nitrate and 6 to 10 parts of water is heated to 100 C. for the time necessary ,for gelatinization of the starch. It is then subjected to reduced pressure for the purpose of rendering the entire mass porous. The cooled mass is then easily granulated and dried. This ers of explosive compositions by critical concentrations'of organic halogen compounds. In certain cases, uniformity of detonation of the explosives is promoted by polyhalogen compounds in accordance with the process disclosed in this specification.

In the above described explosives, we have indicated concentrations of 5% to 10% of the or ganic halogen compounds. Although we do not limit ourselves to these concentrations, we recognize that certain relatively low critical concentrations are necessary, otherwise it overruns its application as a sensitizing component. Furthermore, larger concentrations of the polyhalogen compounds tends to cause excessive adherence of the materials, with loss of granulation and sensitization.

Many other organic halogen derivatives have been tested not only for their sensitizing eifects, but also for their qualities as freezing point depressors of nitroglycerine. not demonstrated any advantage 7 over hexachloronaphthalene as sensitizers, it was found that certain mixtures of hexachloropropylene and nitrcglycerine did not freeze above -70 C.

Measurements of disruptive effects by the sand test gave us the following data wherein it is observed that 6-10% of hexachloronaphthalene yields maxima of sensitization. A comparison of 4 and 5 demonstrates that nitroglycerine can be displaced in certain explosives by an equal Although they have amount of hexachloronaphthalene without a loss of power.

Percentages of- Grams sand N tm crushed Sensi- 8111- 1 Wood 8 NaNO; tizer phur meal explosive 3. 0 l4. 0 so. 0 29. 40 8. 0 13. 0 71. 0 36. 00 15. 0 l0. 0 60. 0 28. 40 12. 5 7. 0 68. 0 38. 00 12. 5 1. 0 I 68. 0 as. 10

sensitization both inexplosives having no sensitizer and also in explosives containing as much as 6% of nitroglycerine. A comparison of 3 and 4 further demonstrates the practicability of using KNOa, in preference to NaNOa, to obtain an increase of sensitization.

Percentages of- Materisls used in grams phur Hexachloronapbthalene N itroglycerine Detonation by influence . l neg.

3. A potentially detonating explosive containing an alkali metal compound having an excess of combined oxygen, said explosive being sensitized with a relatively small percentage of a polyhalogen organic compound containing more than two halogen atoms, said compound being a non-odorous solid whose. melting point is substantially below 220 degrees centigrade.

4. A potentially detonating explosive containing an alkali metal compound having an excess of combined oxygen, said explosive being sensitized with a relatively small percentage of a mixture of polyhalogenated' naphthalenes containing more than two halogen atoms.

JOHN w. DAWSON. WILLIAM M. DEHN.