US2083143A - Explosives - Google Patents

Description

Patented June 8, 1937 EXPLO SIV'ES Laud S. Byers, Glendale, Calif., asslgnor, by

mesne assignments, to Halafax Explosives Coml any, Los Angeles, Calif., a corporation of Delaware No Drawing. Application August 20, 19 34,

\ Serial No. 740,636

'7 Claims.

This invention relates to a method of compounding ingredients for use in explosive com POSltlOI'lSflIld to combinations of specified ingredients in particular proportions whereby an explosive characterized by stability to temperature changes, or protracted exposure to high temperatures, ease and cheapness of manufacture, water resistance, and ability to propagate and detonate with great efiiciency is obtained. q

Although there are numerous compounds and compositions which may be termed to b explosives because they will detonate when set off with a fulminating cap, very few of such compositions or compounds are adapted for actual commercial manufacture and use. In addition to detonating ability, an explosive must fulfill a number of separate and distinct requirements, 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 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 explo- 25 sion; it should be capable of withstanding percussion, 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 sticks of 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 directed to a combination of specific ingredients inspec'ific proportions which result in an explosive. answering all of the above requirements. p

, Nitrated cellulose varies in nitrogen content andthis invention contemplates the use of nitrated cellulose containing 12% or more of nitrogen.- r

More specifically stated, theinvention in part relates to a method whereby more nitrated cellulose, containing more than 12% of nitrogen, may be mixed together into stable solution in a liquid mixture of isomers of dinitrotoluene, a result which has not been attained heretofore; The solution thus obtained is e'minently suited for use in various explosives; particularlyin explosives coml C taining chlorates' and nitrates. The resulting 5 solution increases the efficiency of the final explo= sive compound whereas suspensions or dispensions of nitrocellulose in such mixture of isomers has a tendency to deaden and reduce the propagating and detonating characteristics of an explosive compound.

A still further object of the present invention is to disclose and provideaco mplete explosive compound in which a relatively shredded woodis used instead of the customary ground wood flour or wood pulp. Heretofore, the art has believed that in order to produce an efiicient explosive it was necessary to grind arid combine the ingredients in a very extreme state of fineness so as to obtain a perfectly homogeneous uniform mixture of all of the ingredients. I have found; on the other hand, that whencertain of the ingredients, such as the wood, are ground very fine or are used in .the form of fiourjeffects of much lower efllciency are obtained than is the case when the wood is shredded and has an appreciable and definite size.- The shredded particles of wood have, a tendency to inter-weave with each other, increasing the plastic moldability of the explosive compound, thus holding it in place when packed into upright orvertical drill holes. I

It is an object of this invention, therefore, to 25 disclose and provide an explosive of great power, said explosive being characterized by an absence of noxious fumes upon explosion and by its ability to-maintain a moldable plastic form upon storage or exposure to varying temperatures.

Another object of the invention is to disclose and provide an explosive composition which is water-resistant and which may be used in wet holes without impairment of its detonating, rende ing and disruptive effects.

A further object is to disclose and provide as an ingredient for use in explosivecompositions a stable solution of nitrocellulose containing more than-12% ofnitrogen in a mixture of isomers of dinitrotoluene. p c H A still further object of the invention is to disclose and provide a method of dissolving nitrocellulose containing more than 12% ofnitrogen in aliquid mixture of isomers of dinitrotoluene. l These and other obj ects usesa'nd advantages of the invention will be apparent to-those skilled in the art from the following detailed description of the ingredients,their manneriof compounding, I and the proportions in which they are to be combined.

As stated hereinabove, the highly nitratedcottons'are not solublein solvents whereas cottons of, low nitration, 'such ascollodion cotton'contaming less than'10%'of 'nltrogenis soluble. The 55 physical properties of a solution of nitrated cotton in a solvent diifer greatly from the physical properties of a suspension of nitrated cotton in the same solvent. Highly nitrated cotton, for example, is not soluble in a liquid mixture of isomers of dinitrotoluene but instead results in the formation of a suspension. This suspension is of increased vicosity but has the property of absorbing appreciable quantities of water. As a result, explosive compounds containing such suspension are not water-resistant. It has been discovered that if nitrated cotton, that is nitrocellulose containing more than about 12% of nitrogen, is first dissolved in a volatile solvent, such as ethyl acetate, acetone, amyl acetate, and the like, and the solution thus obtained then incorporated and mixed with the liquid mixture of isomers of dinitrotoluene with which such nitrocellulose-solvent mixture is miscible, then upon evaporation of the volatile solvent, such as amyl acetate, it will be found that the nitrocellulose is retained in stable solution (or colloidal solution) in the liquid mixture of isomers. The physical properties of the product prepared in this manner are entirely difierent from a product prepared by simply adding nitrocellulose to the isomers. Whereas the latter absorbs large quantities of water, the product of this invention absorbs inappreciable and negligible quantities of water. The product of this invention effectively renders explosive compounds water-resistant whereas the product made by a simple. mixture does not; the product of this invention enhances the disrup- 0 ting, detonating and explosive characteristics of a compound, whereas the product of a simple mixture detracts from these qualities and deaden the compound.

In preparing the product of this invention, a solution is first made containing say 20 to 40 percent of nitrated cellulose (more than about 12% nitrogen content) in a suitable volatile solvent, preferably acetone. This-solution is then mixed with a mixture of DNT isomers in quantity sufficient to introduce from about to 10% of nitrated cellulose. The mixture is then slowly agitated and, if desired, heated to above the boiling point of the original solvent, the vapors of the solvent being carried off and separately condensed for reuse in cyclic operation of the process. In order to produce a product eminently suited for use in explosives, from about 1 to 2 percentof nitrogen content should be thus incorporated in the mixture of DNT isomers.

The mixture 6f isomers of dinitrotoluene which is capable of being successfully used in this explosive 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 preferably 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. The mixture of isomers should be .iree 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.

A complete explosive which has been found to have exceptionally good detonation, propagation, water-resistance and plasticity, may be made by combining the following ingredients in the proportions stated:

I Percent Sodium nitrate 19-23 Potassium chlorate 38-41 Shredded wood 13-14 Liquid DNT isomers 23 Ar-2'7 /z Nitrocellulose (more than about 12% nitrogen content) l /.;--2

It is to be understood that the nitrocellulose is incorporated with the liquid DNT isomers in the manner described above before being added to Obviously, some small quantity or proportion of the wood may be slightly coarser and also slightly finer in particle size, but at least 60% of the wood should be of a size between 20 and 30 mesh. A wood shredded to pass a 14 mesh sieve and be retained on a 35 mesh sieve can be used.

The explosives coming within the scope of this invention can be used for general blasting, quarrying and mining purposes, but are particularly adaptable for mining use. The fumes involved are innoxious and as a result miners can be reentering shafts and drifts within a few minutes after detonation without experiencing undesirable physiological effects. The explosive is rather bulky, weighing about 42 pounds per cubic foot, loose weight. In stick form a 50 pound case, net weight, of 8 by 1 inch sticks will contain about 145 sticks instead of the sticks of similar size contained in a 0 pound case of ammonia dynamite or nitroglycerine dynamite. .In explosive and breaking effect, the explosive of this invention is equivalent to the stardard 50%-60% ammonia or nitroglycerine dynamite. :I'he standard 8 inch sticks of the explosive will propagate through an air gap of at least 1 inch and as much as 2 inches when a stick is cut in half, the ends longitudinally spaced and a cap inserted in one half only. No loss in sensitiveness takes place upon storage of the explosive for a prolonged period of time.

The explosive composition may be subjected to the action of water for several hours without becoming saturated and without losing its explosive characteristics. No hardening or deterioration takes place even upon exposure of the sticks to extremely high temperatures to degrees F., or below 22 F.) for protracted periods of time. No bleeding, separation, or hardening takes place upon exposure to sudden or radical changes of temperature.

In the event the explosive is to be used at very low temperatures, such as temperatures below 20 F., it may be desirable to incorporate from 0.5% to 2% toluene. 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.

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. An industrial explosive consisting essentially of about 38% to 41% of potassium chlorate, 19% to 23% of sodium nitrate, 13% to 14% of shredded wood and 23.25% to 27.5% of a liquid mixture of dinitrotoluene isomers having an initial crystallization temperature of between 25 F. and 60 F., said liquid dinitrotoluene mixture containing from about 0.5% to 2.5% of nitrated cellulose having a nitrogen content of over 12%.

2. An industrial explosive consisting essentially of about 38% to 41% of potassium chlorate, 19% to 23% of sodium nitrate, 13% to 14% of shredded wood and 23.25% to 27.5% of a liquid mixture of dinitrotoluene isomers having an initial crystallization temperature of between 25 F. and 60 F., said liquid dinitrotoluene mixture containing from about 0.5% to 2.5% of nitrated cellulose having a nitrogen content of over 12%, said explosive being characterized by its ability to retain its explosive characteristics upon storage for protracted periods of time.

3. An industrial explosive consisting essentially of about 38% to 41% of potassium chlorate, 19% to 23% of sodium nitrate, 13% to 14% of shredded wood and 23.25% to 27.5% of a liquid mixture of dinitrotoluene isomers having an initial crystallization temperature of between 25 F.-

wood, these ingredients being in progressively decreasing proportions in the order stated, said industrial explosive being characterized by the presence of from about 0.5% to about 2.5% of nitrated cellulose of about 12% nitrogen content in solution in said liquid mixture of dinitrotoluene isomers, said liquid mixture of dinitrotoluene isomers having an initial crystallization temperature of between F. and 60 F.

5. In a method of producing industrial ex- -plosives having water resisting properties and capable of being stored for protracted periods of time without, loss of sensitiveness, the steps of: dissolving nitrated cellulose containing more than about 12% nitrogen in acetone, mixing said solution with a liquid mixture of isomers of dinitrotoluene, said hquid mixture having an initial crystallization temperature of between 35 F. and 60 F., evaporating the major portion of the acetone and incorporating the solution of nitrocellulose in said liquid dinitrotoluene in a mixture of chlorate, nitrate and shredded wood to from an industrial explosive.

6. In a method of producing industrial explosives having water resisting properties and capable of being stored for protracted periods of time without loss of sensitiveness, the steps of 2 dissolving nitrated cellulose containing more than about 12% nitrogen in acetone, mixing said solution with a liquid mixture of isomers of dinitrotoluene, said liquid mixture having an initial crystallization temperature of between 35 F. and

. 60 F., evaporating the major portion of the acetone, and then incorporating from about 23.25% to 30% by weight of said solution in a mixture of potassium chlorate, sodium nitrate and shredded wood. g

'7. An industrial explosive of the character defined in claim 6, in which the major portion of the shredded wood passes a ZO-mesh sieve and is retained on a 30-mesh sieve.

LAUD S. BYERS.