CA1111256A - Water-in-oil emulsion explosive composition - Google Patents

Abstract

WATER-IN-OIL EMULSION EXPLOSIVE COMPOSITION

ABSTRACT OF THE DISCLOSURE
Water-in-oil explosive compositions are provided which are No. 6 cap sensitive in cartridges having diameters of 1.25 inches and less and which contain from about 3.5% to about 8% by weight of a hydrocarbon fuel including an emulsifier, from about 10% to about 22% by weight of water, from about 0.25% to about 15%
by weight of closed cell void containing materials r from about 65%
to about 85% by weight of inorganic oxidizer salt, optionally, up to about 15% by weight of an auxiliary fuel and no explosive ingredients nor detonation catalysts.

Description

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¦l BACKGROUND OF THE INVENTION
This application is a continuation-in-part of Serial No. 740,094, filed November 9, 1976.
l~ This invention relates to water-in-oil emulsion ¦lexplosive compositions. In a specific aspect, tbis invention relates to improved water-in-oil emulsion explosive compositions ,Iwhich are detonable by a No. 6 blasting cap, and are made of ~¦nonexplosive components. -¦¦ Water-in-oil emulsion type blasting agents were first Ijdisclosed by Bluhm in U.S. Patent No. 3,447,978. These emulsion ¦type blasting agents contain an aqueous solution of inorganic ~¦oxidizer salt that is emulsified as the dispersed phase within a continuous carbonaceous fuel phase, and a uniformly distributed gaseous component. Such emulsion type blasting agents have many ¦ advantages over water slurry type blasting agents, but they are ¦ not cap sensitive. Therefore, such materials require a booster in order to effect their detonation.
- Cattermole, et al, in U.S. Reissue Patent No. 28,060 teaches the addition of certain amine nitrate compounds to the ~
~Iwater-ln-oil emulsion compositions in order to assure that once ;;
jtdetonated, the explosion will propagate in a 2 or 3 inch ¦Iborehole. However, the mere addition of amine nitrates to the jlconventional water-in-oil emulsion type blasting agents will ~not render such materials cap sensitive. U.S. 3,770,522 suggests l~that the addition of materials such as trinitrotoluene, ¦~
pentaerythritol tetranitrate, and the like to conventional llwater_in_oil blasting agents will render them cap sensitive.
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However, it is well known that such materials are explosives and are more expensive than conventional ingredients that go into the water-in-oil emulsion blasting agents, and the ~ resulting products do not adequately perform in small diameter llboreholes and are undesirable from other standpoints.
¦~ U.S. 3,715,247 and U.S. 3,765,964 disclose that water-in-oil emulsion explosive compositions can be prepared which retain all the advantages of the emulsion blasting agents i~described above, but are cap sensitive without the use of an ¦ explosive ingredient. These latter two patents disclose the addition of a detonation sensitizer or catalyst, such as an inorganic metal compound of Atomic No. 13 or greater, and strontium compounds.
Therefore, heretofore water-in-oil emulsion type blasting agents have been rendered cap sensitive by the ¦laddition of an explosive ingredient, or a specific detonation catalyst.

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'~UMMARY OF' THE IMVFNTION ~
rn accordallce with an aspect o~ the invention there is provicled a water-in-oil explosive composition that contains no explosive compounds nor detonation catalysts but that is detonable by a No. 6 cap in cartridge diameters of ahout 1.25 inches and less consisting essentially of:
a1 a continuous phase of a earbonaeeous fuel;
b) a discontinuous aqueous phase containing an inorganic oxidizer composed principally of ammonium nitrate;
c) from about 0~5~ to about 2% by weight of the composition of a water-in oil type emulsifier capable of forming said composition; ~ ' d) from 0 to about 15% by weight thereof of an auxiliary fuel; and e) suf~ieient elosed eell void eontaining material to yield a density of said explosive eomposition in the range of from about 0.9 g/ee to about 1.35 g/ee.
Aecording to the invention, improved water-in-oil explosive eompositions are provided that ean be detonated with a No. 6 eap at diameters of 1.25 inches and less and that do not eontain an explosive ingredient nor a detonation eatalyst. The improv~d eap sensitive water-in-oil emulsion of the subjeet invention consists essentially of from about 3.5% to about 8~ by weight of a hydroearbon fuel including -`
an emulsifier; from about 10~ to about 22~ by weight of water; from about 0.25% to about 15% by weight of closed eell void-eontaining materials sufficient to impart a density of from about 0.90 to about 1.35 g/ce to said explosive eom-position; from about 65% to about 85~ by weight of inorganic oxidizer salt; and optionally, up to about 15% by weight of an auxiliary fuel sueh as aluminum. The inoxganie oxidizer salt eomprises principally ammonium nitrate and ean eontain another inorganic nitrate and/or an inorganie perehlorate.

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DETAILED DESCRIPTION OF THE INVENTION
Thus, I have discovered that water-in-oil emulsion ,explosive compositions can be made and detonated with a No. 6 cap llat diameters of 1.25 inches and less by the utilization of l~hydrocarbon fuels, water, oxidizer salts, closed cell Ivoid-containing materials, and optionally, aluminum or the like in ! the percentages set forth above and in the absence of explosive ¦icompositions or detonation catalysts. It is necessary that the llproportions of the constituents be held in the ranges set forth 1 above and that closed cell void-containing materials be utilized.
The water-in-oil explosive emulsions of the subject invention should preferably contain as the continuous phase thereof from about 3.5~ to about 8~ by weight of a carbonaceous fuel component including an emulsifier. The carbonaceous fuel component utilizable within the scope of this invention can include most hydrocarbons, for example, paraffinic, olefinic, naphthenic, aromatic, saturated or unsaturated hydrocarbons. In general, the carbonaceous fuel is a water immiscible emulsifiable ~ -Ifuel that is either liquid or li~uefiable at a temperature up to labout 200 degrees F, and preferably between about 110 degrees F
and about 160 degrees F. At least 2.5~ by weight of the total composition should be either a wax or oil, or mixture thereof. It , is preferable that the carbonaceous fuel include a combination of I`ia wax and an oil. Preferably, the wax content will range from llabout 2.5% to about 4.5% by weight and the oil content will range ~`from about 0.5~ to about 5.5% by weight of the total emulsion.
WaXes having melting points of at least 80 degrees F, such as petrolatum wax, microcrystalline wax, and paraffin wax, ! - -mineral waxes such as ozocerite and montan wax, animal waxes such l -as spermacetic wax, and insect waxes such as beeswax and Chinese i wax can be used in accordance with the present invention. ¦ -¦IPreferred waxes include waxes identified by the trade designations I,INDRA 1153, INDRA 5055-G, INDRA 4350-E, INDRA 2126-E and INDRA
~2119 sold by Industrial Raw Materials Corporation, and a similar ¦ -~
wax sold by Mobil Oil Corporation under the trade designation j ! MOBIL 150. Other suitable waxes are WITCO 110X and WITCO ML-445, ¦
which are marketed by Witco Chemical Co., Inc. The most preferred Iwaxes are a blend of microcrystalline waxes and paraffin such as the wax sold under the trade designation IN~RA 2119 identified above. In this regard, field testing has shown that more shelf stable emulsions can be obtained by using a blend o~
Imicrocyrstalline wax and paraffin rather than microcrystalline or paraffin wax alone.
Examples of suitable oils include the various petroleum oils, vegetable oils, and various grades of dinitrotoluene; a highly refined mineral oil sold by Atlantic Refining Company under the trade designation ATREOL; a white mineral oil sold by Witco Chemical Company, Inc. under the trade designation KAYDOL; and the like.
¦¦ The carbonaceous fuel component will also include the emulsifier which is used within the scope of the invention. The llemulsifier is a water-in-oil emulsifier such as those derivable l¦from sorbitol by esterification with removal of one molecule of llwater such as sorbitan fatty acid esters, for example, sorbitan monolaurate, sorùltan monooleate, sorbitan monopalmitate, rorbitrn

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B5954C ~l ~onostearate, and sorbitan tristearate. Other useful materials ~comprise mono- and diglycerides of fat-forming fatty acids, as well as polyoxyethylene sorbitol esters, such as polyethylene sorbitol beeswax derivative materials and polyoxyethylene(4)1auryl ether, polyoxyethylene(2)ether, polyoxyethylene(2)stearyl ether, polyoxyalkylene oleate, polyoxyalkylene laurate, oleyl acid phosphate, substituted oxazolines and phosphate esters, mixt~res thereof and the like. In general, the emulsifiers should be present in an amount ranging from about 0.5% to about 2~0~ by ~ weight of the total composition, and preferably from about 0.8%
to about 1.2% by weight of the total composition ~hile its presence is not necessary, the emulsions of the subject invention can also contain up to about 15~ by weight l,of an auxiliary fuel, such as aluminum, aluminum alloys, ' magnesium, and the like. Particulate aluminum is the preferred such auxiliary fuel.
The discontinuous aqueous phase of the subject emulsion should contain inorganic oxidizer salts dissolved in from about l! 10% to about 22% water, by weight of the total emulsion.
1~ The inorganic oxidizer salt generally comprises from ~'about 65~ to about 85% by weight of the emulsion. The inorganic ¦
oxidizer salt should consist principally of ammonium nitrate, although up to about 20% by weight of the total composition can comprise either another inorganic nitrate such as an alkali or '~alkaline earth metal nitrate, or an inorganic perchlorate such as ammonium perchlorate or an alkali or alkaline earth metal perchlorate, or a mixture thereof. Preferably, the inorganic '', I ~' ., ~

~ - 7 -oxidizer salt will include up to about 10% of another inorganic nitrate and up to about 10% of an inorganic perchlorate, by weight of the total composition. The ammonium nitrate should preferably ~comprise from about 50% to about 70% by weight of the total composition, and will more preferably comprise from about 57~ to about 70% by weight of the total composition. Furthermore, relative minor amounts of other oxidizer salts can also be present in the emulsions of the subject invention. When ano~her inorganic l'nitrate is present in the oxidizer, it is preferred that the Initrate be sodium nitrate, although potassium nitrate and calcium ¦nitrate can also be used, for example. When a perchlorate is ¦present, it is preferred that ammonium or sodium perchlorate be used even though potassium and calcium perchlorate can be used, l Eor example.
¦ In compositions of the subject invention wherein the lloxidizer salt comprises ammonium nitrate and another inorganic ¦ nitrate with no perchlorate, it is preferred that at least about ¦ 2.5~ and up to about 20% by weight of the total emulsion be the !i other said inorganic nitrate. In such case, it is most preferable ,that from about 5% to about 10~ by weight of the total emulsion comprise the other inorganic nitrate. Also, in this case, it is preferred that the ratio of ammonium nitrate to the other , inorganic nitrate be in the range of from about 5-7:1. Further-!!
''more, when the oxidizer salt consists of ammonium nitrate and a ~perchlorate salt, it is preferred that perchlorate be present in 'an amount in the range of from about 3% to about 20~ by weight of ~the total emulsion and more preferably from about 5% to about 10%

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by wei~ht of the total emulsion. Again it is preferred that the ratio of ammonium nitrate to perchlorate be in the range of from about 5-7:1. In the most preferred emulsions of the subject invention, it is preferred that ammonium nitrate, another nitrate ,(preferably sodium nitrate), and a perchlorate be present in relative amounts of about 5-6:1:1 to about 6-7:1:0.5, respectively.
The closed cell void containing material which is used in the scope of the subject invention is herein meant to encompass any particulate material which comprises closed cell, hollow cavities. Each particle of the material can contain one or more closed cells, and the cells can contain a gas, such as air, or can ~be evacuated or partially evacuated. Sufficient closed cell llyoid containing ma~erial should be utilized to yield a density in ¦
,~the resulting emulsion of from about 0.90 to about 1.35 g/cc. In general~ for any emulsion explosive composition made according to the ranges described herein, the maximum density will vary from about 1.35 to about 1.00 g/cc as the water content varies from about 10% to about 22% by weight. Thus, if the fuel and inorganic ,oxidizer salt content are held constant, the maximum density will i decrease from about 0.01 to about 0.04 g/cc for each 1% increase ~in the water content of the emulsion in the range from about 10 weight percent to about 22 weight percent thereof. The term "maximum density" as used herein refers to the maximum density at i -~
iwhich any emulsion explosive composition formulated within the ~`
prescribed ranges can be detonated by a No. 6 cap at a cartridge ,`diameter of 1.25 inches at 70-80 degrees F and from 18 to 24 hours after the composition is made. Furthermore, for any specified , !

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percentage of water within the prescribed range, the maximum density of the emulsion will also vary as a function of the fuel ,and inorganic oxidizer salt content. Although the emulsion explosives of the present invention will preferably comprise at least about 2~5 weight percent wax, substituting oil for wax in i ~ I
I the carbonaceous fuel phase will decrease the maximum density of !~
, the emulsions from about 0.005 to about 0.015 g/cc for each weight;
percent of oil so substituted.
Il Substituting an inorganic nitrate other than ammonium ''nitrate for the inorganic perchlorate component of the subject emulsions will decrease their maximum density from about 0.008 ¦to about 0.01 g/cc for each weight percent of inorganic nitrate so substituted. Substituting an inorganic perchlorate for the llother lnorganic nitrate will increase the maximum density from l,about 0.008 to about 0.01 g/cc for each weight percent of inorganic perchlorate substituted. I
Substituting ammonium nitra~e for either the other i! inorganic nitrate or the inorganic perchlorate component of the ' s ¦iformulations will decrease its maximum density from about 0.002 'to about 0.01 g/cc for each weight percent of ammonium nitrate ,so substituted. On the other hand, substituting ammonium nitrate ¦
for both the other inorganic nitrate and the inorganic perchlorate¦
'components will leave the maximum density of the resulting `emulsion explosive substantially unchanged, although the explosive power and low temperature sensitivity of the emulsion will be diminished.
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The maximum density for any formulation of the subject invention can be easily determined. In essence, all formulations ' of the subject invention can be detonated by a No. 6 cap in 1.25 I,inch diameters at densities of 0.9 grams per cubic centimeter and i ~ higher. The maximum density, however, will vary as generally described above. This maximum de~sity can be determined by merely~
increasing the density of any formulation of the subject invention by varying the content of the closed cell void containing material 'luntil detonation fails to occur by a No. 6 cap in a cartridge Idiameter of 1.25 inches for samples with densities from 0.01 to about 0.02 grams per cubic centimeter apart. Following the guidelines set forth above, no more than 2 to 4 samples need be made for each matrix in order to determine the maximum density of that particular formulation.
The preferred compositions of the subject invention have densities in the range of from about 1.1 to about 1.3 g/cc. In general, the water-in-oil emulsions of the subject invention can ¦contain from about 0.25% to about 15~ by weight of the closed cell void containing material. The preferred closed cell void . 20 1I containing materials which can be utilized within the scope of the-llsubject invention are discrete glass spheres having a particle Ijsize within the range of about 10 to about 175 microns. In ~general, the bulk density of such particles can be within the llrange of about 0.1 to about 0.4 g/cc. Some preferred glass ',microbubbles which can be utilized within the scope of the subject jinvention are the microbubbles sold by 3M Company and which have ¦la particle si~e distribution in the range of from about 10 to 5Ç~
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. I , B5954C ~i about 160 microns and a nominal size in the range of about 60 to 70 microns, and densities in the range of from about 0.1 to about 0.4 g/cc. The most preferred of such microbubbles sold by 3M
,Company are distributed under the trade designation B15/250.
, Other preferred such glass microbubbles are sold under the trade designation of Eccospheres by Emerson & Cumming, Inc., and ¦
generally have a particle size range from about 4~ to about 175 microns at a bulk density of about 0.15 to about 0.4 g/cc. Other !! .
,'suitable microbubbles include the inorganic microspheres sold i¦under the trade designation of Q-CEL by Philadelphia Quartz Company. In general the water-in-oil emulsions of the subject linvention can contain from about 0.9% to about 15% by weight of ¦Ithe glass microbubbles.
¦ The closed cell void containing material can be made of I,inert or reducing materials. For example, phenol-formaldehyde ¦Imicroballoons can be utilized within the scope of this invention. ¦
It is noted, however, that if the phenol-formaldehyde microballoons are utilized, the microballoons themselves are a ¦! ~uel component for the explosive and their fuel value should be Itaken into consideration when designing a water-in-oil emulsion explosive composition. Another closed cell void containing material which can be used within the scope of the subject invention is the saran microspheres sold by Dow Chemical Company.
The saran microspheres have a diameter of about 30 microns and a particle density of about 0.032 g/cc. Because of the low bulk ~density of the saran microspheres, it is preferred that only from about 0.25% to about 1~ by we`ight thereof be used in tlle ~water-in-oil emulsions of the subject invention.
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, 1~ - 12 -B5954C j In general, I have found that merely imparting the same , density to compositions which would otherwise fall within the ~scope of the subject invention by entrained air bubbles or by ~ porous glass agglomerates and the llke, rather than the closed 5 ll cell void containing material, will~not yield No. 6 cap sensitive explosives that will detonate in io25 inches and smaller diameter ~ -cartridges. Thus, it was quite unexpected that the use of the glass microbubbles described above in the water-in-oil emulsion l formulations of the subject invention would contribute to form a ' cap sensitive explosive, especially in view of the fact that glass ¦microbubbles and other closed cell void containing materials have ~been utilized in conventional water gel explosives and they do not~
produce the same effect in such water gels as they do in my Iemulsion formulations.
ll The general criteria for cap sensitivity is that the explosive be sensitive to a No. 6 blasting cap at a cartridge diameter of 1.25 inch under normal temperature conditions. The Icap sensitive explosive emulsions of the subject invention are ¦shelf stable, which means they exhibit shelf stability of at least ~6 months and typically 1 year or more. The explosives of the ¦Isubject invention should not desensitize during normal operation, ,e.g., due to adverse weather conditions or should not be readily ; ) subject to dead pressing. Dead pressing occurs when the shock I! wave propagated from an explosion in one borehole co~presses the '~explosive in an adjacent borehole so that its density is 1~ .
,lincreased to such an extent that it is no longer detonable.

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Il Furthermore, explosives of the subject invention are 'Inot so sensitive that they will cause hole-to-hole propagation.
Hole-to-hole propagation occurs when one hole goes off and the l percusslon wave from that explosion sets orf an explosive in an ,`adjacent borehole. When this occurs, you get a simultaneous ¦lexplosion in all boreholes. The simultaneous explosions resulting from hole-to-hole propagation can build up huge shock waves and intense vibrations that are detrimental to buildings, roads, bridges, or other structures often located adjacent to the lo l! blasting site. I
I ThereEore, the cap sensitive explosive emulsions of ¦lthe subject invention survive use in a variet~y of environments including mines which are cold and damp, wet and dry boreholes, ~ trenching operations in developed areas, underwater usage such as ditching under rivers and lakes, and quarrying operations.
In general, the water-in-oil emulsion explosive compositions of the subject invention are sensitive at 20 degrees F and lower and have excellent storage stability. Emulsions I designed to be utilized under frlgid conditions or stored more ¦jthan six months should preferably contain the inorganic ¦¦perchlorate as a component of the inorganic oxidizer salt portion 1, of the emulsion.
!, The improved emulsions of the subject invention are ¦Ipreferably made by premixing the water and the inorganic oxidizer ! salts in a first premix, and the carbonaceous fuel and emulsifier i¦in the second premix. The two premixes are heated, if necessar~v.

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i B5954C li ' The first premix is generally heated until the salts are ~ ~
completely dissolved (about 120 to 205 degrees F), and the second ~premix is heated~ if necessary, until the carbonaceous fuel has l liquefied (generally about 120 degrees F or more if wax materials , are utilized). The premixes are then blended together and emulsified, and thereafter the glass microbubbles are added until the density is lowered to the required range. In the continuous manufacture of the emulsion compositions, it is preferred to ' l prepare an aqueous solution containing the oxidizers in one tank land to prepare a mix of the organic fuel components (excluding the ilemulsifier) in another tank. The two liquid mixes and the emulsifier are then pumped separately into a mixing device wherein Ithey are emulsified. The emulsion is next pumped to a blender ¦Iwhere the glass microbubbles and auxiliary fuel, if desired, are ¦ladded and uniformly blended to complete the water-in-oil emulsion.l !, The resulting emulsion is then proce~sed through a Bursa filler or !
other conventional device into packages of desired diameters.
¦For exampler theremulsion explosives can be packaged in spiral ,wound or convolutes polymer laminated paper cartridges.
I` The following examples are given to better facilitate ¦,the understanding of the subject invention but are not intended to limit the scope thereof.
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i EXAMPLE 1 The compositions set forth in Table 1 below were prepared by mixing a premix of water and the inorganic oxidizers 'lat 160 degrees F, and a second premlx of the carbonaceous fuel and Ithe emulsifier at 130 degrees F. The first premix was then slowlyl lladded to the second premix with agitation to obtain a water-in-oil !
¦lemulsion Thereafter, the glass microbubbles and aluminum (when I , desired) were blended into the emulsion to form the final ¦composition.
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~ 2 ~3 l i l ~i TABLE 1 !~ Compositions Ingredients 1 _ 2 3 _ 4 I,waxl 3 2.85 3.0 2.85 "oil 1 0.95 1.0 0.95 'emulsifier3 ' 1 0.95 1.0 0.95 ~water 12 11.4012.0 11.40 ~ammonium nitrate 61 57.9567.6 64.22 l,sodium nitrate 10 9.5 3.0 2.85 ilammonium perchlorate10 9.5 0.0 0.0 sodium perchlorate 0 0.010.4 9.88 llglass microbubbles4 2 1.90 2.0 1.90 ¦I,aluminum5 0 5.00 0.0 5.00 ¦lldensity (g/cc) 1.15 1.171.15 1.17 Il I
jll ~ Paraffin wax sold under the trade designation INDRA 2119 by Industrial Raw Materials Corporation 2 - Kaydol Oil U.S.P. sold by Witco Chemical Co., Inc. ¦

3 - Sorbitan monooleate sold by ICI-U.S. under the trademark SPAN

1i 4 - Microbubbles sold by 3M Company under the trade designation Il 5 - Aluminum powder sold by Reynolds Aluminum Company under the ; ¦~ trade designation HPS-10 l All of the compositions set forth in Table 1 were ,~extruded or tamped into paper tubes having a one-half inch I -~
: ¦,diameter, sealed and then detonated with a conventional No. 6 ,~electric blasting cap. Furthermore, emulsions having the same i,makeup as compositions 1-4 have been stored for periods of up to ¦
I itwo years without loss of sensitivity.

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The compositions set forth in Table 2 below were ,~-prepared by the same method which was utilized to prepare the .
; compositions 1~4 in Table 1.

Compositions In~redients 5 6 7 8 wax 2.71 2.660 3 2.85 .
," 0.90 0.885 1 0.95 emulsifier3 0.90 0.885 1 0.95 water 10.84 10.62 12 11.40 I'ammonium nitrate 55.09 59.60 66 62.70 1 sodium nitrate 9.03 8.85 10 9.50 1 ~:
ammonium perchlorate9.03 5.00 5 4.75 Il , I,glass microbubbles41.50 1.50 2 1.90 ~aluminum5 10.00 10.00 0 5.00 density (g/cc) 1.25 1.25 1.15 1.17 , :
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1 - a paraffin and microcrystalline wax blend sold by Witco '~ Chemical Co. under the trademark Witco 110X. i ~,2 - Kaydol Oil U.S.P. sold by Witco Chemical Co., Inc.
;3 - Mono- and ~iglycerides of fa~ forming fatty acids sold by ICU-U.S. under the trademark ATMOS 300

4 - Microbubbles sold by 3M Company under the trade designation

5 - Aluminum powder solder by Reynolds Aluminum Company under the `. trade designation HPS-10 i ~ ~
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Compositions 5 and 6 set forth in Table 2 were extruded or tamped into paper tubes having diameters of 1.25 inches;
compositions 7 and 8 were extruded or tamped into paper tubes llhaving a 1 inch diameter, and all were sealed and detonated with a ,conventional No. 6 electric blasting cap.

A series of emulsion explosive compositions was made by ¦
adding various amounts of B15/250 microbubbles described in l Example 2, and water to an emulsion matrix formulation set forth ¦ in Table 3 below.

ngredient Weight % Used in Matr1x wax 1.71 - 1.78 l wax3 1.71 - 1.78 15 l oil4 1.16 - 1.22 emulsifier5 1.15 - 1.22 ¦ ammonium nitrate 78.46 - 78.61 ` ~ `
sodium nitrate 3.44 - 3.54 sodium perchlorate 12.06 - 12.13 I ~
IlThe actual weights of the ingredients used within the various ¦ test specimens varied no more than set forth in the ranges in Table 3.
A microcrystalline wax sold under the trade designation of Witco X145A by Witco Chemical Company.
,, A paraffin wax sold under the trade designation of Aristo 143 ¦ by Witco Chemical Company.
! A white mineral oil sold under the trade designation of Atreol 34 by Atlantic Refining Company.
, A sorbitan monooleate emulsifier sold under the trademark of ¦ Glycomul "O" by Glyco Chemicals Inc.
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I, Samples were prepared using the above ingredients, but ;varying the water content from 10~ to 22~ by weight. The emul-sions were packaged in 1~25 x 8 inch paper cartridges and tested 'with a No. 6 cap about 18 to 24 hours after being made. Maximum .! .
~densities were then determined for each water content by varying the content of the above described microbubbles to vary the density until a detonation and failure occurred for samples with densities G.01 to 0.02 g/cc apart. The results of those tests are, ,tabulated in Table 4 below. I

il WEIGHT % WATER MAXIMUM DETONATION
IN PRODUC__MATRIX DENSITY (g/cc) 10.0 1.32 ll 12.2 1.30 i 14.0 1.28 16.0 1.26 18.0 1.20 20,Q 1.14 1 22.0 1.07 1' EXAMPLE 4 ~! A series of emulsion explosive compositions was prepared¦
with differing wax:oil ratios in the carbonaceous fuel phase and ammonium nitrate:sodium nitrate:sodium perchlorate ratios in the discontinuous aqueous phase. Five different matrices containing ¦
'the same amount of water were first made by mixing a premix of water and the inorganic oxidizers at 160F, and a second premix of the carbonaceous fuel and emulsifier at 130F. The first premix was then slowly added to the second premix with agitation to ' I

, . - 20 -25~i ¦jobtain a water-in-oil emulsion. Thereafter the maximum densities for each matrix were determined in the manner set forth in Example 3. The compositions and maximum densities of the five basic l,,matrices are set forth in Table 5 below.
¦I TABLE 5 Il MATRICES
¦i (Compositions Expressed in Wt. %) ~INGREDIENTS _ 1 2 _ 3 4 _5 I'waxl 1.5 1.5 liwax 1.5 1.5 -- -- --oil3 1.0 1.0 4.0 4.1 4.0 emulsifier4 1.0 1.0 1.0 1.0 1.0 lammonium nitrate67.6 67O6 67.6 65.9 81.0 !sodium nitrate 3.0 13,~4 3.0 15.0 --¦sodium perchlorate10.4 ~-- 10.4 -- --lwater 14.0 14 0 14.0 14.0 14.0 maximum density (g/cc)1.28 1 18 1.25 1.21 1.25 IIlA microcrystalline wax sold under the trade designation of WITCO
Il X145A by Witco Chemical Company.
~2A paraffin wax sold under the trade designation of Aristo 143 ;
by Wi tco Chemical CompanyO
,3A white mineral oil sold under the trade designation of Atreol ¦1 34 by Atlantic Refining Company.
~, A Sorbitan monooleate emulsifier sold under the trademark of li Glycomul "O" by Glyco Chemicals Inc.
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B5954C ~i The above examples illustrate that extremely sensitive explosives which are made in the form of water-in-oil type emulsions can be made in accordance with the subject invention.
The water-in-oil emulsions of the subject invention are sensitive S to conventional No. 6 blasting caps and are suitable for detonation in small diameters of about 1.25 inches and less.
Furthermore, the explosives are suitable as primers for other less sensitive explosives.
~ The sub~ect water-in-oil emulsions are sensitized ~l~without the use of conventional high explosives and without the ¦luse of special initiation or detonation catalysts, but yet possess ¦lall the advantages of the conventional water-in-oil type emulsion blasting agents. They will not produce headaches; they possess l~water resistance as an intrinsic property of their physical form; ;
~Ithey are safe from initiation by fire, rifle bullet, impact, l,friction or static electricity; they lend themselves to continuous !
ilprocessin~ and can be extruded durin~ manufacture; and they are ~noncorrosive, that is, they are not severely acidic or basic.
1~ While this invention has been described in relation to ¦
1'l its preferred embodiments, it is to be understood that various l,modifications thereof will be apparent to those of ordinary skill ¦
; "in the art upon reading this specification and it is intended to cover all such modifications as fall within the scope of the appended claims.

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Claims (41)

WHAT IS CLAIMED IS:

1. A water-in-oil explosive composition that is detonable by a No. 6 cap in cartridge diameters of about 1.25 inches and less consisting of:
a) a continuous phase of a carbonaceous fuel;
b) a discontinuous aqueous phase containing an inorganic oxidizer composed principally of ammonium nitrate;
c) from about 0.5% to about 2% by weight of the composition of an emulsifier selected from sorbitan fatty esters, glycerides of fat-forming fatty acids, polyoxyethylene sorbitol esters, polyoxyethylene ethers, polyoxyalkylene oleate, polyoxyalkylene laurate, oleyl acid phosphate, substituted oxazolines and phosphate esters thereof;
d) up to about 15% by weight thereof of an auxiliary fuel; and e) sufficient closed cell void containing material to yield a density of said explosive composition in the range of from about 0.90 g/cc to about 1.35 g/cc.

2. The explosive composition of Claim 1 wherein from about 2.5% to about 20% by weight of said composition is an inorganic nitrate other than ammonium nitrate.

3. The explosive composition of Claim 2 wherein from about 5% to about 10% by weight of said composition is an inorganic nitrate other than ammonium nitrate.

4. The explosive composition of Claim 2 wherein said inorganic nitrate is selected from alkali metal and alkaline earth metal nitrates.

5. The explosive composition of Claim 4 wherein said inorganic nitrate is sodium nitrate.

6. The explosive composition of Claim 1 comprising from about 3% to about 20% by weight of an inorganic perchlorate.

7. The explosive composition of Claim 6 comprising from about 5% to about 10% by weight of an inorganic perchlorate.

8. The explosive composition of Claim 6 wherein said inorganic perchlorate is selected from ammonium, alkali metal and alkaline earth metal perchlorates.

9. The explosive composition of Claim 1 wherein said carbonaceous fuel comprises water immiscible emulsifiable material selected from the group consisting of petrolatum, microcrystalline, paraffin, mineral, animal, and insect waxes, petroleum oils, and vegetable oils.

10. The explosive composition of Claim 9 wherein up to about 5.5% by weight thereof is an oil.

11. The explosive composition of Claim 9 wherein up to about 4.5% by weight thereof is a wax.

12. The explosive composition of Claim 11 wherein the wax comprises a blend of microcrystalline wax and paraffin wax.

13. The explosive composition of Claim 1 wherein said auxiliary fuel is particulate aluminum.

14. The explosive composition of Claim 1 wherein said closed cell void containing material is present in an amount of from about 0.25% to about 15% by weight of said composition.

15. The explosive composition of Claim 14 wherein said closed cell void containing material is glass microbubbles ranging from about 0.9% to about 15% by weight of the total composition.

16. The explosive composition of Claim 14 wherein said closed cell void containing material is saran microspheres ranging from about 0.25% to about 1% by weight of the total composition.

17. The explosive composition of Claim 1 wherein said discontinuous aqueous phase comprises from about 10% to about 22%
water by weight of the total composition.

18. The explosive composition of Claim 1 wherein said continuous phase of carbonaceous fuel including said emulsifier is from about 3.5% to about 8% by weight of said explosive composition.

19. The explosive composition of Claim 1 wherein said inorganic oxidizer is present in an amount of from about 65% to 85% by weight of said emulsion.

20. A water-in-oil explosive composition that contains no explosive compounds nor detonation catalysts but that is detonable by a No. 6 cap in cartridge diameters of about 1.25 inches and less consisting essentially of:
a) a continuous phase of a carbonaceous fuel;
b) a discontinuous aqueous phase containing an inorganic oxidizer composed principally of ammonium nitrate;
c) from about 0.5% to about 2% by weight of the composition of a water-in-oil type emulsifier capable of forming said composition;
d) from 0 to about 15% by weight thereof of an auxiliary fuel; and e) sufficient closed cell void containing material to yield a density of said explosive composition in the range of from about 0.9 g/cc to about 1.35 g/cc.

21. The water-in-oil explosive composition of Claim 20 wherein said continuous phase of a carbonaceous fuel including said emulsifier is present in an amount of the range of from about 3.5% to about 8% by weight of said composition.

22. The water-in-oil explosive composition of Claim 20 wherein the water in said discontinuous aqueous phase is present in an amount ranging from about 10% to about 22% by weight of said composition.

23. The water-in-oil explosive composition of Claim 20 wherein said inorganic oxidizer is present in an amount ranging from about 65% to about 85% by weight of said composition.

24. The explosive composition of Claim 20 wherein said carbonaceous fuel comprises a water immiscible material selected from the group consisting of petrolatum, microcrystalline, paraffin, mineral, animal and insect waxes, petroleum oils and vegetable oils.

25. The explosive composition of Claim 24 wherein from about 0.5% to about 5.5% by weight thereof is an oil.

26. The explosive composition of Claim 24 wherein from about 2.5% to about 4.5% by weight thereof is a wax.

27. The explosive composition of Claim 24 wherein the wax comprises a blend of microcrystalline wax and paraffin wax.

28. The explosive composition of Claim 20 wherein said auxiliary fuel is selected from aluminum, aluminum alloys, and magnesium.

29. The explosive composition of Claim 28 wherein said auxiliary fuel is aluminum.

30. The explosive composition of Claim 20 wherein said emulsifier is selected from sorbitan fatty esters, glycerides of fat-forming fatty acids, polyoxyethylene sorbitol esters, polyoxyethylene ethers, polyoxyalkylene oleate, polyoxyalkylene laurate, oleyl acid phosphate, substituted oxazolines and phosphate esters thereof.

31. The explosive composition of Claim 20 wherein said inorganic oxidizer is ammonium nitrate and an inorganic nitrate selected from alkali metal and alkaline earth metal nitrates.

32. The explosive composition of Claim 31 wherein the ratio of said ammonium nitrate to said inorganic nitrate is in the range of 5-7:1.

33. The explosive composition of Claim 20 wherein said inorganic oxidizer is ammonium nitrate and an inorganic perchlorate selected from ammonium, alkali metal and alkaline earth metal perchlorates.

34. The explosive composition of Claim 33 wherein the ratio of ammonium nitrate to inorganic perchlorate is in the range of from about 5-7:1.

35. The explosive composition of Claim 20 wherein said inorganic oxidizer is ammonium nitrate and another inorganic nitrate selected from alkali metal and alkaline earth metal nitrates, and an inorganic perchlorate selected from ammonium, alkali and alkaline earth metal perchlorates.

36. The explosive composition of Claim 35 wherein the ratio of ammonium nitrate, said inorganic nitrate and said inorganic perchlorate is in the range of from about 5-6:1:1 to about 6-7:1:0.5, respectively.

37. The explosive composition of Claim 35 wherein said other inorganic nitrate is sodium nitrate.

38. The explosive composition of Claim 35 wherein said inorganic perchlorate is ammonium perchlorate.

39. The explosive composition of Claim 35 wherein said inorganic perchlorate is sodium perchlorate.

40. The explosive composition of Claim 20 wherein said closed cell void containing material is glass microbubbles ranging from about 0.9% to about 15% by weight of the total composition.

41. The explosive composition of Claim 20 wherein said closed cell void containing material is saran microspheres ranging from about 0.25% to about 1% by weight of the total composition.