US2079105A - Explosive - Google Patents

Description

Patented May 4, 1937 UNITED STATES PATE'NT OFFICE EXPLO SIVE No Drawing.

Application August 20, 1934,

Serial No. 740,635

3 Claims.

This invention relates to an improved explosive characterized by stability to temperature changes or protracted exposure to high temperatures, ease and cheapness of manufacture, and

its ability to propagate and detonate with great efficiency.

- It is acknowledgedthat for a great many years attempts have been made to produce explosives containing chlorates and nitrates and although numerous mixtures capable of detonating have been made, none of'them have been adapted for actual commercial manufacture and use. In addition to detonating. ability, an explosive must fulfill a number of separate'and distinct require- 5 ments, among-them the following: the explosive should not freeze or become insensitive at low temperatures; it should not bleed or liberate a liquid constituent upon exposure to high temperatures; it should not harden with age; it 2 should maintain a relatively sticky, moldable constituency capable of being. rammed into upwardly directed holes without, falling out; it should not liberate noxious fumes upon explosion; it should be capable of withstanding per- 5 cussion, blows and rough handling; upon being ignited in the open, it should not burn with great rapidity or with explosive force; it should not be subject to ignition by a sputtering fuse; upon being detonated in a hole, additional sticksof 3 the explosive separated more than one inch from the original stick, should also detonate instantaneously.

Explosives answering individual requirements have been made heretofore but none of the explosives of the prior art answered all of these requirements. This invention, however,-is' di rected to a combination of specific ingredients in specific proportions which result in an explosive answering all of the above requirements.

Generally stated, the invention relates to an explosive consisting of 28% to 31% of potassium chlorate and 10% to 14% ofdisintegrated wood, combined" with sodium nitrate and a mixture of isomers of dinitrotoluene. The specific require- 5 ments, characteristics and properties of the various ingredients used'will be explained in greater detail hereinafter.

An object of this invention, therefore, is to disclose and provide an explosive of great power, 59 said'explosive being characterized by an absence of noxious fumes upon explosion. Anotherob-ject is to disclose and provide an explosive which maintains a moldable or plastic form upon storage and exposure to varying temperatures and which will not harden.

A still further object is to disclose and provide a method of compounding an explosive which is substantially free from' nitrocellulose 60 andnitrated glycerine.

These and other objects, advantages and adaptations of this invention will became apparent to those skilled in the art from the following detailed description of the ingredients, their manner of compounding, and the proportions in which they are combined.

Generally stated, the explosive consists essentially of potassium chlorate, sodium nitrate, and ground but fibrous wood, and a mixture of isomers of dinitrotoluene. The inorganic elements, such as potassium chlorate and sodium nitrate, need not be described as ordinary commercial grades are eminently suited for use in the explosive of this invention. The sodium nitrate may be either Chilean or natural nitrate or synthetic. It has been found, however, that the other two major ingredients have to be carefully selected so as to answer certain requirements.

.The ground wood should preferably be an uncooked, finely divided but fibrous wood consisting essentially of particles varying from about to of an inch in length. This relatively coarse wood should pass a 20 mesh screen but be practically completely retained on a mesh screen. Not more than about 5% should pass the 60 mesh screen. As will be apparent to those skilled in the art, this ground wood differs greatly from the wood flour or very finely ground wood or pulp ordinarily used in the manufacture of dynamite and other explosives. As a matter of fact, the very finely divided wood flour can not be successfully used in the composition of this invention. It has been found that although any wood may be ground to the required size, ground spruce appears to produce better results. The moisture content of the wood should be relatively low and preferably all of the ingredients should be in a dry state.

The mixture of isomers of dinitrotoluene which is capable of being successfully used in thisexplosive has'a low crystallizing temperature. Ordinarily, it is a liquid having a specific gravity of about 1.3. Crystallization should begin to be observed at temperatures below 60 F. and pref erably at temperatures of about 52 F. Mixtures having crystallization temperatures of between 40 F. and 60 F. have been successfully used. Most of the mixture should consist of the 1-2-4 and 1-2-6 isomers of dinitrotoluene with but a minor proportion of meta isomers. of isomers should be free from sulfonic acids or free acids. The mixture, furthermore, should contain not more than about 2%3% of compounds or substances volatile at C. The presence of some toluene is not objectionable, however. Preferably, the explosive contains from 10% to 14% by weight ofthe ground wood and from about 14.5% to 16.5% of the mixture of isomers of dinitrotoluene. The preferred explo- The mixture sive, therefore, contains the following ingredients:

The ingredients above described are preferably mixed in the following manner: the chlorate and nitrate are first intimately mixed together, the ground wood being then added and the mixing continued. After the wood has been thoroughly incorporated, the liquid dinitrotoluene mixture is added and the mixing continued until the entire mass becomes homogeneous. This mass is then of a consistency capable of retaining its shape when pressed between the fingers. It will be found to have a weight per cubic foot in loose condition of between 38 and 42 pounds.

In addition to the above ingredients, normal antacids, such as calcium carbonate, etc., can be added. A very minute quantity of manganese dioxide or powdered alumina may be added whenever it is desired to increase the sensitiveness of the compound.

When it is desired to produce an explosive of stickier or pastier consistency, a small proportion of dextrin may be incorporated. The dextrin may amount up to 20% of the mixture of isomers or up to about 3% by weight of the entire compound. When dextrin is used, the small quantities of ground wood are to be used, namely, in the neighborhood of 10% or 11% instead of 13% or 14%. In order to increase the plasticity, the dextrin should be first incorporated in the mixture of isomers of dinitrotoluene by agitation and slight warming, if necessary. This causes the mixture of isomers to assume a liquid but viscous consistency. This viscous liquid is then added to the intermixture of the other ingredients and the resulting explosive will be found to be much more plastic than that first described hereinabove.

An explosive made in accordance with this invention and tested and approved by the United States Bureau of Explosives contained the ingredients in the following proportions:

Per cent Potassium chlorate 29 Sodium nitrate 41 Ground wood 10.5 Isomers of DNT 15.5 Dextrin 2.5 Manganese dioxide 0.75 Antacid 0.75

The explosives coming within the scope of this invention can be used for general blasting, quarrying and mining purposes. The fumes evolved are innocuous and as a result, miners can reenter shafts and drifts within a few minutes after detonation without experiencing undesirable physiological effects. The eight inch sticks of the explosive will propagate an air gap of 1%; inches. Weight for weight, the above explosive will exert a greater force than standard 50% nitroglycerine dynamite. No hardening or deterioration takes place even upon exposure of the sticks to extreme temperature conditions for a period of six months.

Because of the relatively low weight of the explosive, ordinary 1%; x 8 inch sticks will weigh in the neighborhood of 6 ounces apiece instead of the customary 8 ounces which normal dynamite sticks of the same size weigh. A stick of the explosive of this invention exerts a greater explosive force than a stick of standard 50% nitroglycerine dynamite. As explosives are sold by the pound (in 50 pound cases), a case of the explosive of this invention will contain from 130 to 145 sticks, thereby permitting the user to obtain 30% more explosive effect per case than is the case with dynamite.

The explosive can be used in Wet holes, the oily mixture of dinitrotoluene isomers (particularly when partly thickened by the aid of dextrin or other substance capable of producing the same effect) preventing rapid absorption of water by the mixture. When a cut and exposed end of a stick of this explosive is submerged in water, the water will permeate to a depth of only about 1 inch at the end of 30 minutes. Water does not appear to pass into the mixture by capillary attraction to any material extent.

In the event the explosive is to be used at very low temperatures, such as temperatures below 30 F., or to be stored at very low temperatures for a protracted period of time, it may be desirable to incorporate from 0.5% to 2% of toluene. The incorporation of this ingredient is preferably made by mixing the toluene with the isomers of dinitrotoluene. In this relation the toluene appears to exert a crystallization-retarding effect upon the isomers of dinitrotoluene which may have a tendency to crystallize out at such low temperatures, thereby causing the mass to become more firm. Sticks of the explosive have been maintained at temperatures of 28 F. for protracted periods of time and their explosive force was. not deleteriously affected even at such temperature. The explosive, therefore, is nonfreezing, thereby distinguishing from normal nitroglycerine dynamite.

The mixture of dinitrotoluene isomers referred to hereinabove appears essential for the successful preparation of the explosive and other nitrated hydrocarbons, such as nitrobenzene, can not be substituted therefor.

I claim:

1. A non-freezable plastic explosive characterized by its ability to explode without the formation ofnoxious gases, consisting of 28% to 31% of potassium chlorate, 38% to 42% of sodium nitrate, 14.5% to 16.5% of a liquid mixture of 1-2-4 and 1-2-6 isomers of dinitrotoluene having an initial crystallization temperature between 35 F. and 60 F. and 10% to 14% by weight of ground wood, said wood consisting essentially of particles passing a 20 mesh screen and remaining on a 60 mesh screen.

2. A non-freezable plastic explosive characterized by its ability to explode without the formation of noxious. gases, consisting of 28% to 31% of potassium chlorate, 38% to 42% of sodi-,

um nitrate, 14.5% to 16.5% of a liquid mixture of isomers of dinitrotoluene having an initial crystalline temperature of between 35 F. and 60 F., and 10% to 14% by weight of ground wood passing a 20 mesh screen but retained on a 60 mesh screen.

3. A chlorate-nitrate explosive containing from about 66% to 73% of a mixture of alkali chlorate and alkali nitrate, the proportion of nitrate exceeding the proportion of chlorate in said mixture, and also containing a liquid mixture of isomers of dinitrotoluene having an in- P itial crystallizing temperature between about 35 F. and 60 F. and from about 10% to 14% of ground wood substantially passing a 20 mesh screen and retained on a 60 mesh screen.

LAUD S. BYERS.