US2338120A - Explosive composition - Google Patents

Description

Patented Jan. 4, 1944 EXPLOSIVE COMPOSITION Robert W. Lawrence, Wilmington, to Hercules Powder Company,

Del, asxlgnor Wilmington,

Del, a corporation oi Delaware No Drawing. Application June 29, 1940, Serial No. 343,163

9 Claims. (Cl. 52-7) This invention relates to explosive compositions and to explosive formulations which have a reduced sensitivity to impact. More particularly, thi invention relates to a method of reducing the impact sensitivity of nitroglycerin without adversely affecting the explosives strength.

Nitroglycerin alone and in admixture with the nitroglycols, the nitrated sugars and the like has been widely used as a constituent of explosive compositions such as the dynamites and gelatine dynamites. Nitroglycerin has also found applicm tion in the liquid form for oil well shooting. However, a serious disadvantage in its use for these purposes is its extremely high degree of sensitivity to impact which causes it to be very dangerous during handling and especially during truck transportation, loading of bombs, lowering into oil wells, and other operations its sensitivity to impact has made its manufacture, compounding, and use extremely hazardous even under favorable conditions, and although the introduction of many safety measures has improved the working conditions many accidents occur which cause damage to property and 10s of life.

Due to the high impact sensitivity, nitroglycerin should not be transported in the liquid state, and even in mixture with oxidizing agents and reducing or carbonaceous materials, special precautions are necessary during transportation. To overcome these hazards it has been suggested that the nitroglycerin be colloided with a high percentage of niirocotton. However such an admixture does not lend itself readily to compound ing into the desired type explosive on. Ithasrurtherbeensnggested byHaleinlLS. 2,004,941, that nitroglycerin be admixed with nitroethyl as these materials will reduce its sensitivity. considerable quantity of the nitroethy not only reduces-the impact sensitivity. but also makes the mixture insensitive to blasting caps. Purthermoretheremaybeatthesametimea. considerable reduction in the explosive strength. It may be noted that even dinitroethy hasthelowoxygenbalanceoi-130% audits explosive energy is low.

Itistheobiectotthisinveniiontom-ovidea material which when with ni reduces its sensitivity to impact without unfavorably ailecfing its strength.

Afurtherobjectofthisinventonistopmvide ni which may be handled with greater safety.

However, the addition oi any 40 A further object oi this invention is to provide explosive compositions which have reduced sensitivity to impact.

A further object or this invention is to provide a liquid explosive adaptable for use in oil well shooting.

A still further object of this invention is to provide explosive compositions which are not sensitive to impact, but which will detonate with a commercial blasting cap.

Other objects will be apparent hereinafter.

In general, the objects of this invention have been accomplished by mixing with the nitroglycerin now known to the art various percentages of nitro. The nitroparamns are insensitive to impact and will not shoot under ordinary confinement when primed with a No. 8 blasting cap, but will when in admixture with nitrogLvcerin develop approximately the same explosive power as an equal weight of the nitroglycerin that it displaces. Thus, by admixing nitroparafflnwithnitroglycerin andusingthese admixtures in various explosive compositions, explosives have been produced which have a reduced sensitivity to impactbut which do not have a decreased explosive power.

More the objects of this invention wereaccomplisbdbyadmixingonepartoinitrogiycerin with one part of nitromethane. The admixture produwd had an oxygen balance of -l8% and the explodve energy of the mixture was equivalent to that of pure nitroglycerin The 50-50 mixture of nitroglycerin and nitromethane was insensitive to impact but was sensitive to detonation by a commercial blasting cap. By varying the percentage of nitromethzme addedtothenitroglycerlmithasbeenfoimdthat about 15% nitromethane markedly reduces the sensitivity of the nitroglycerin and that an additionof over about 50% nitromethane to nitroglycerin reduces the sensitivity of the nitroglycerin toamiintwherenboosterchargeisrequiredto siredluadiingtheretoaproperamountoinitmlnordertoshowmoreth g g ottheadditimofniimpammntonitroglyeerin,

usblelisaivaiinwhichthepropertiesoi'varloua I Hei btoflali oizkg. weight in the U. 8. Bureau oiMinea imp act machine to produce either shots out of trials or 6 lailnres ii trials. First column shows height for 6 shots and second for-5 failures.

I 8 indicates shot, Findicaies (allure when ilring with leommercial blasting cap, either No. 6 or No. 8 in size.

'In the above table the nitroglycerin which was used did not include any of the various materials such as nitroglycol or nitrated sugars that are sometimes added to nitroglycerin. However. the mixing of nitroparamns with nitroglycerin;- containing materials such as the nltroglycols or nitrated sugars etiects a reduction in the sensitlveness similar to the reduction which is efl'ected when the nitroparaflln is added to pure nitroglycerin.

A nitroglycerin composition which comprised 42% nitroglycerin, 41% nitroglycol and 17% aucroseoctanitrate was mixed with varying portions of nitromethane and the oxygen balance and sensitiveness or the admixture determined. The

results are given in Table 2.

Table 2 mm "N. 0." ig Banaitlvcneas I o 100 -o. 1 s No. 0. so -n.o BNoJc b. so 00 l5.s Fblo.8cap.

Table 3 fig g "N. o." ai- Sensitivanees o 100 +aa s No. a. $0 70 -0. 8 B No. 6 cap. 40 co -l4.0 e No. a. so so --is. s r m. a cap.

From the foregoing results it will be seen that nitromethane aifects the nitroglycerin alone or in admixture with other of the nitric esters and,

therefore, wherein. this specification and claims is used the term nitroglycerin, it should be understood that by the term, the compound by itself or with addition or partial substitution of any of the commonly used freezing point depressants such as, for example, ethylene glycol dinitrate, nitrat ed polymerized glycerin, nitrated sugars, nitrated chlorhydrins and the like is contemplated. The

asseneo term nitroglycerin as here described is well known and accepted in the art. It has also been found that the nitrobaramns will reduce the sensitiveness of the above mentioned nitric esters when they are used alone.

It will be observed that sensitiveness of the hitroglycerin as shown in the abov tables has been materially decreased by the addition of as little as 16% of nitromethane. and that by the time the percentage of nltromethane has been raised to about 80%, the mixture has become quite insensitive to impact; and, that on further raising of the percentage of nitromethane, the admixture becomes less sensitive until it will no lonser detonate with a No. 8 blasting cap. Detonation of the insensitive composition may be effected by boosters; e. g., such as a half stick of 40% dynamite, or a charge of TNT or tetryl. The use of such boosters is oftentimes desirable and is to be understood as contemplated by this invention.

In addition to the reduction of sensitivity which is effected by the addition of nitromethane to the nitroglycerin, the nitromethane also, due to its low molecular weight and its low freezing point, efle'ctlvely lowers the freezing point of nitroglycerin. Since the nitromethane added to the nitroglycerin lowers the freezing point, it is unnecessary to include with the nitroglycerin high percentages of freezing point depressants such as, nitrated glycols and nitrated sugars. This is advantageous since nitration of the mixtures may sometimes present diiilculties not experienced when nitrating glycerin alone.

The liquid explosives comprising mixtures of nitroglycerin and nltromethane in accordance with this invention are highly desirable in oil well shooting. Thus, for example, a mixture of nitroglycerin and nitromethane, 15-25, is very much safer to handle in the liquid state than pure nitroglycerin and actually provides a means of using a high explosive composition safely. The use of mixtures 01 nitroglycerin containing as much as 50% nitromethane for shooting oil wells has been found advantageous by the inclusion of a booster charge of TNT or tetryl. The handling and loading of the 50-430 mixture of nitroglycerin and nitromethane even with the inclusion of the booster charge is relatively safe because the assembly is not sensitive to impact.

The sensitivity of various explosive compositions containing nitroglycerin, oxidizing salts and carbonaceous materials may be reduced by the addition of nitromethane to the composition either by adding it to the nitroglycerin before the nitroglycerin is compounded with the other ingredients or by adding it to the explosive composition after the mixing procedure is under way.

Thus the nitroparailin may be added to the explosive composition at any time during the preparation thereof, or tcthe individual ingredients. Any of the various explosive compositions now containing nitroglycerin may be reduced in sensitivity by the addition 01 nitromethane without reducing their explosiv power and by this addition increased safety is obtained in the compounding. P cking and use of the various explosives. The hazard of handling the explosives is materially reduced and in particular the hazard accompanying the packing of ordinary nitroglycerin explosives into cartridges manufactured of paper, plastics or metal is substantially decreased.

To show the various type explosives which may be compounded by the use of nitromethane, Table 4 is given which lists a dynamite, an ammonium nitrate dynamite, a gelatin dynamite, and an extra gelatin dynamite composition that includes as an ingredient nitromethane:

Table 4 A ll i l) Dymb Ammonium Gelatin tgm' mile "vi gelatin ymmu an e dynamite Nitroglyccrin 20 I 25. 0 2n. n Nltl'omlthamil 20 5 25. 0 l0. 0 Nitrocellulose 2.0 11,.- Sodiu m lllirnli 4s 23 R0. 0 1&2. n Ammonium niirate... m 'ZILO Mnnioc meal 7 Wood flour. T 4.0 1.0 asseh 4 4.0 1.0 Starch... l. 7.5 Suliur.... 4 Ln (-hnlk. l l Lo Lo I00. 0 100. 0 HXLU 100.0

From the above table, it is obvious that the nitromethane of this invention may be compound ed with most 01' the various explosive compositions now known to the art. The addition or nitromethane to these explosive compositions, materiaily decreases the sensitivity of the composition. The advantage of this invention lies in the fact that the sensitivity of various explosive compositions may be reduced without the reduction of their explosive power.

While throughout the foregoing examples I have used nitromethane, I have also found that other nitroparaflins such as, for example, dinitroethane, dinitropropane may be substituted for the nitromethane or may be admixed therewith in order to obtain the decreased sensitivity desired. The nitroparafllns with materially lower oxygen balances, such as, nitroethane, nitropropane, and nitrobutane may also be used provided they are mixed with nitromethane to give a mixture with an oxygen balance greater than about 100%.

It will be understood that the details and examples hereinbeiore set forth are illustrative only. and that the invention as broadly described and claimed is in no way limited thereby.

What I claim and desired to protect by Letters Patent is:

1. A dynamite including an oxidizing salt, a carbonaceous material, and an explosive ingredient, said ingredient comprising an admixture of a liquid explosive nitric ester and at least 15% by weight of a nitroparafiin composition selected from the group consisting of nitromethane, dlnitroethane, dinitropropane. mixture of nitroethane and nitromethane, mixture of nitropropane and nitromethane, and mixture of nitrobuteas and nitromethane. said dynamite being characterized by a much lower sensitivity to shock than a corresponding dynamite in which the nitroparaflin has been replaced by an equal weight of explosive nitric ester.

2. A dynamite including an oxidizing salt, a carbonaceous material, and an explosive ingredlent, said ingredient comprising an admixture of a liquid explosive nitric ester and at least 15% by weight 01' a nitroparamn composition selected from the group consisting of nitromethane. dinitroethane, dinitropropane, mixture oi nitmethane and uitroaiethaue, mixture 01' ultrourm pane and nitromethane, and mixture of nitrobutane and nitromethane, said dynamite being characterized by being insensitive to a blow from a 2 kg. weight dropped from a height 'of at least 15 cm. when tested on the U. 8. Bureau of Mines impact machine.

3. A dynamite including an oxidizing salt, a carbonaceous material, and an explosive ingredient, said ingredient comprising an admixture of a liquid explosive nitric ester and at least 15% by weight of nitromethane, said dynamite being characterized by being insensitive to a blow from a 2 kg. weight dropped from a height of at least 15 cm. when tested on the U. S. Bureau of Mines impact machine.

4. A dynamite including an oxidizing salt, a carbonaceousmaterial, and an explosive ingredient, said ingredient comprising an admixture oi a liquid explosive nitric ester and at least 15% by weight of dinitroethane, said dynamite being characterized by being insensitive to a blow from a 2 kg. weight dropped from a height oi at least 15 cm. when tested on the U. S. Bureau of Mines impact machine.

5. A dynamite including an oxidizing salt, a carbonaceous material, and an explosive ingredient, said ingredient comprising an admixture of a liquid explosive nitric ester and at least 15% by weight of dinitrcpropane, said dynamite being characterized by being insensitive to a blow from a 2 kg. weight dropped from a height of at least 15 cm. when tested on the U. S. Bureau of Mines impact machine.

6. A dynamite including an oxidizing salt, a

carbonaceous material, and an explosive ingredient, said ingredient comprising an admixture of nitroglycerin and at least 15% by weight oi mtrometnane, said dynamite being characterized by being insensitive to a blow irom a 2 kg. weight dropped from a height of at least 15 cm. when tested on the U. S. Bureau of Mines impact machine.

I. A gelatin dynamite including an oxidizing salt, a. carbonaceous material, and an explosive ingredient, said ingredient comprising an admixture of nitroglycerin, nitrocellulose and at least 15% by weight of nitromethane, said gelatin dynamite being characterized by being insensitive to a blow from a 2 kg. weight dropped from a height of at least 15 cm. when tested on the U. 8. Bureau or Mines impact machine.

8. A dynamite including an oxidizing salt, a carbonaceous material, and an explosive ingredient, said ingredient comprising an admixture oi mtroglycerin and at least 15% by weight of dinitroethane, said dynamite being characterized by being insensitive to a blow from a 2 kg. weight dropped from a height of at least 15 cm. when tested on the U. S. Bureau of Mines impact machine.

9. A dynamite including an oxidizing salt, a carbonaceous material, and an explosive ingredient, said ingredient comprising an admixture of nitroglycerin and at least 15% by weight of dlnitropropane, said dynamite being characterized by being insensitive to a blow from a 2 kg.- weight dropped from a height 01 at least 15 cm. when tested on the U. S. Bureau of Mines impact machine.

ROBERT W. LAWRENCE.

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