US2131574A - Explosive - Google Patents

Description

Patented Se t. 27, 1938 axrposrya Ralph A. Tapley, McMastel-ville, Quebec, Canada,

p y, W aware assignor to E. I. du Pont de- -Nemonra &'Comin, M, a corporation of Del- No Drawing. "Almlication July 24, 1936, Serial No.92,370. In Canada November 19, 1935 llclaima.

My invention relates a high explosive composition and more particularly to a high explo- "sive composition from which other explosive compositions of diiferent types and strengths can subsequently be made. High explosives of different types, as made at the present time, comprise mixtures of a variety of diflerent ingredients. Among the ingredients used are nitroglycerin and similar nitric esters. gelatinizing agents for the nitroglycerin, various oxygen carrying ingredients, such as ammonium nitrate, sodium nitrate, potassium chlorate, etc... absorbents for the nitroglycerin, such as wood pulp, starch, flour, corn meal and other diil'erent materials of similar composition, anti-acid materials, such as chalk for neutralizing incipient acidity thatmay develop, sulphur, sodium chloride and various other materials.

The materials mentioned above are all used for specific reasons and "according to well defined principles which are familiar to those skilled in the art. By varying the proportions and kinds of the various ingredients used, it is readily pos-- sible to control the strength, density, velocity, sensitiveness, water resistance, fumes and other properties of the explosive to suit the purpose a to which the explosive is-to be applied;

According to the ingredients used in dynaniites and: their properties, various well recognized types of dynamites are produced which are classified by those skilled in the art, into the following general roups:

1. Straight I 2. Ammonia dynamites. g

3. Gelatin dynamites.

. 4. Ammonia gelatins.

5. Permissible dynamites.

It will be seen from the above that there are manytypes of'high explosive compositions and that their properties are the result of formulat- U ingthe powders according to certain definite and well defined principles-e Dynamite manufacture, at the present time, is carried out in plants of considerable size, and must, of necessity, involve many preiiminary operations. Among such operations may bemcntioned the preparation and-mixing of 'nitrating acids, the manufacture of .ammonium nitrate, the preparation and control oi various nonexplosive -ingredients, including their drying, grindingnand screening, as well as the manufacture of nitroglycerin and the disposal of the nitrating waste acids. The above operations are costly and complicated, and require central manufacturing plants. from which the finished ex- Chalk (approximatelyL...

plosives may be shipped. These operationsare' all necessary before the diifei'ent ingredients can be brought together, mixed and packed, to give the diflerent types of dynamites desired. No other method of producing the various explosives required has been possible prior to the present invention.

The manufacture of the finished dynamite at central explosive plants has been necessary because of the fact that it is impossible to tansport safely large quantities of nitroglycerin. Nitroglycerin is a necessary ingredient in all the usual dynamite compositions, and is the most hazardous to produce of the various ingredients. The ship-' ment of nitroglycerinby itself on railroads, for example, is out of the question from a safet point of view. 4 g

The transportation of nitroglycerin after its simple absorption inthe necessary amount of materials such as wood pulp, is comparatively safe provided the mixture does not contain more than percent of nitroglycerin. percent straight dynamite is manufactured but. for reasons of safety, must be transported by water. This is necessary because'of the possibility, of exudation of nitroglycerin from the absorbent causing a dangerous condition.

' It will-be readily apparent to one skilledin the art that only a very limited number of different explosives having very limited properties could be manufactured from these high strength straight d'ynamites. Various high nitroglycerin content gelatins are commonly sold in which the nitroglycerin is fixed by gelatinization with varying amounts of nitrocotton but the proportions usually employed give a gelatin so ilrm that it cannot subsequently be broken'up and mixed with other materials. to form .a satisfactory dynamite. A

U. S. Patent 1,944,910 of Woodbury discloses. a method for rendering nitroglycerin safe for transportation at the same time maintaining it in such mixtures as to;allow of its subsequent use in explosives. This was. accomplished by mixing the nitric esters with nitrocotton, absorbent and chalk within the range of quantities. as given below.-

r Example Percent Nitrog'lycerin 75 Nitmcotton 0.5- 2.5 Absorbentie. g., wood pulp), 23.5-

The patent further discloses that in such mixtures a balance is maintained, with increasing nitroglycerin content, between the two mixing materials, nitrocotton and wood pulp. This-is 5 'doneby increasing the amount of nitrocotton as the nitroglycerin content is increased and the wood pulp content decreased. It is stated that by proceeding thus, a decrease in the amount of absorbent is compensated for by an increase of tained when using the compositions of the patent in subsequent reworking to form explosive compositions of lower strengths are recited.

While the starting compositions shown by the patent are very suitablefor the subsequent production \of straight dynamites, ammonia dynamites and permissible dynamites, I have found them not entirely suitable for gelatin dynamites andgammonia gelatins. Broadly stated, I find them more suitable for explosive compositions of a pulverulent nature than for explosive compositions of a gelatinous nature.

I have found that in making the starting composition for explosives of a gelatinous nature, the Y workability of the starting composition and more particularly the workability of the subsequently formed lower strength explosive is considerably improved by the addition of materials having the effect of reducing the friction between the am particles in the mixing operation. The addition of such lubricating materials is preferablymade in both the mixing of the starting composition and in the subsequent remixing of such compositions with other materials to form lower strength explosives. The lubricatingmaterials which I.

employ in the starting composition comprisematerials which are substantially insoluble in water and nitroglycerin and possess lubricating properties in gelatinous, explosives: such asstarchy glo -carbohydrates, wax impregnated combustibles such as those described in U, S. 1,828 788, but preferably sulphur. The materials'which I prefer for addition in the subsequent remixing are liquid aromatic nitrocompounds but preferably liquid dinitrotoluene or ortho nitrotoluene. While I- have stated that these lubricating materials have the eflect of reducing friction between the particles in the mixture I do not intend to be Q limited to such a theory.

"In the preferred method for carrying out my invention 1 substitute finely diyided sulphur for a'portion of the wood pulp referred to in the compositions disclosed in the above mentioned patent,

substitution being in direct rant and within the limits of 2.0-10.5% of sulphur. 'This substitution. is made in preparing the starting composition. 7 In the subsequent reworking of this starting composition to form lower strength explosives I add so a small percentage (within the limits of 0.2-5%) or liquid dinitrotoluene. Starting compositions which are very suitablejor carrying out my in- J vention are mixtures within the following ranges:

i From such starting compositions many possible combinations may be made for subsequent re working with additional ingredients to form lower aisns'ze viscosity. ,The numerous advantages to be obnitroglycerin. or other liquid nitric ester, together position have been added.v n The materials are strength explosives but my preferred starting composition is: k

Percent Nitroglycerin 85.0 Nltrocotton 1.5 Wood 9 11; 10.3 V Sulphur 2.2 Chalk 1.0

Explosive compositions of the five general m classes referred to may be made from the above starting composition but such a starting composition is more particularly adaptable to forming explosives er, a gelatinous nature for example,

gelatin dynamites or ammonia gelatins. If I wished to produce 40%, ammonia gelatin for example, using the above starting composition, I

would'use the following ingredients per 100 lbs. of finished explosive.

K in Pounds 20- Starting composition 27.7 Ammonium nitrate 6.3. Sodium nitrate 54.7 Ivory nut mea 1.1 Sulphur 5.6 Cornstarch c 1.0 Chalk -i 0.1 Liquid dinitrotoluene 3.5

i This composition is given only by way of example and I do not intend to be limited thereby. The preparation of both the starting composition and the subsequent reworking is preferably done in a nixer, comprising a bowl of non-sparkingmetal or wood, in which the intimate incorpo-' ration of the ingredients is effected by the passage of revolving wheels through and over the material. In preparing my starting composition I place the 40 with the required quantity of nitrocotton, in a pregelatinlzing bowl. This' bowl consists generally of an open vessel of suitable'material with heating means such as a hot water jacket and agitating means such as compressed air. s gelatinized mixture is then run into a mixer such as described in the foregoing and to which the other required ingredients of my starting comthen mixed until a doughy homogeneous product 50 is obtained. This product is suitable for reworking with additional non-explosive ingredients to produce a finished explosive composition.

The method has beenonly briefly described since this method per se does not form a part of my invention and the mixing of the compositions according to my invention could obviously be carried out in any suitable mixing equipment.

I The starting material is then mixed with the my additional non-explosive ingredients and a quantity of dlnitrotoluene or other liquid nitrobody chosen from within the limits given above. Mixing may be by any known method for mixing explosive compositions but as before I-prefer the use of a mixer in which the ingredients are incorporated under wheels. Preferably I add the non-explosive ingredients and the dinitrotoluene to the mixing bowl and after a slight preliminary mixing add therequired quantity of the starting w composition,

It is to be understood that various minor changes may be made the compositions without departing from th spirit of my invention; For an. in place'of nitroglycerin alonertliis '15 compound may be used mixed with various similar materials such as are frequently used for the depression of its freezing point. Such materials comprise nitrated polymerized glycerin, nitrated sugar, ,nitroglycol, nitrated chlorohydrin, etc. and my reference to nitroglycerin in the follow ing claims is intended to include that compound itself and/0r such mixtures: Similarly,'in place of wood pulp, other carbonaceous combustible materials of relatively high absorption value may be used, such as, for example, balsa wood, bagasse V examples or description except as indicated in the following patent claims:

I claim:

1. An explosive composition capable of being subsequently combined with additional ingredients to form nitroglycerin high explosives o1 thegelatinous type which composition comprises between '75 and 90 per cent of at least one liquid nitric ester containing at least two nitrate groups, between 0.5 and 3.0% of a gelatinizing agent, between 13.0 and 2.5 per cent of a combustible absorbent material and between 2.0 and 10.5 per cent of a material substantially insoluble in water and possessing lubricating properties in gelatinous explosives.

2. An explosive composition capable of being subsequently combined with additional ingredients to form nitroglycerin high explosives oi. the gelatinous type which composition comprises between 75 and 90 per cent of nitroglycerin, between 0.5 and 3.0 per cent of a gelatinizing agent for the nitroglycerin, between 13.0 and 2.5 per cent of a combustible absorbent material and be-' tween 2.0 and 10.5 per cent of a material selected from the group consisting of sulphur and starch.

3. An explosive composition capable of being subsequently. combined with additional ingredients to form nitroglycerin high explosives of the gelatinous type which composition comprises between 75 and 90 per cent nitroglycerin, between 0.5 and 3.0 per cent nitrocotton, between 13.0 and 2.5 per cent of a combustible absorbent material and between 2.0 and 10.5 per cent of a material selected from the group consisting of sulphur and starch.

4. An explosive composition capable of being subsequently combined with additional ingredients to form nitroglycerin high explosives of the gelatinous type which composition comprises between 75 and 90 per cent nitroglycerin, between 0.5 and 3.0 per cent nitrocotton, between 13.0 and 2.5 per cent wood pulp and between 2.0 and 10.5 per cent sulphur.

5. An explosive composition capable of subsequently combined with additional ingredients to form nitroglycerin high explosives of the gelatinous type which composition comprises about 85 per cent nitroglycerin,'about 1.5 per cent nitrocotton, about 10.3 per cent wood pulp, about 2.2 per cent sulphur and about 1.0 per cent chalk.

6. A method of manufacturing a balanced explosive composition which comprises preparing a, substantially unbalanced explosive composition comprising nitroglycerin and less than the normal amount cinch-explosive dope ingredients required to produce a finished explosive composition, compensating for the decrease in the amount of absorbent by introducing a small amount of nitrocotton so as to increase the viscosity and gelatinization of the product to hold the nitroglycerin in place against leakage, thereby producing a composition having physical characteristics rendering it safe for handling and transportation and subsequently combining therewith the dope ingredients and an amount of a liquid aromatic nitrocompound between 0.2 and 5.0 per cent of the finished explosive to produce a balanced explosive composition of lower nitroglycerin content.

7. A method of manufacturing a balanced ex;

piosive composition which comprises preparing an unbalanced explosive composition substantially free of oxygen yielding salts comprising between 75.0 and 90.0 per cent nitroglycerin, between 0.5 and 3.0 per cent nitrocotton, between 13.0 and 2.5 per cent of a combustible absorbent v material and between 2.0 and 10.5 per cent of a material substantially insoluble in water and nitroglycerin and possessing lubricating properties when used in gelatinous explosives, thereby producing a composition having characteristics rendering it safe for handling and transportation and subsequently combining themwith the dope ingredients and a liquid aromatic nitrocompound in amount between 0.2 and 5.0 per cent of the finished explosive to produce a balanced explosive composition of lower nitroglycerin content.

8. A method according to claim 6 in which the amount of nitrocotton does not exceed 3.0 per cent of the unbalanced explosive composition.

9. A method of manufacturing a balanced explosive composition which comprises preparing an unbalanced explosive composition substan-' tially free of oxygen yielding salts comprising between 75.0 and 90.0 per cent nitroglycerin, between 0.5 and 3.0 per cent nitrocotton, between 13.0 and 2.5 per cent wood pulp and between 2.0 and 10.5 per cent of sulphur thereby producing a composition having characteristics rendering it safe for handling and transportation and subsequently combining therewith the dope ingredients and liquid dinitrotoluene in amount between 0.2 and 5.0 per cent of the finished explosive to produce a balanced explosive composition of lower nitroglycerin content.

10. A method of manufacturing a balanced ex- 'plosive composition which comprises preparing an unbalanced explosive composition substantially free of oxygen yielding salts comprising approximately 85.0 per cent nitroglycerin, approximately 1.5 percent nitrocotton, approximately 10.3 per cent wood pulp, approximately 2.2 per cent sulphur and approximately 1.0 per cent chalk, thereby producing a composition having characteristics rendering it safe for handling and transportation combining therewith the dope ingredients and liquid dinitrotoluene in amount of 3.5 per cent of the finished explosive to produce a balanced explosive composition of lower nitroglycerin content. 1

11. The method of claim 7 in which the combustible absorbent material is a combustible taken from a group consisting of wood pulp. starch, flour, vegetable piths and a cereal product.

RALPH A. TAPLIY.

and subsequently