US3580751A - Tmetn-inorganic nitrate explosives blended with hot inorganic nitrate - Google Patents

Abstract

EXPLOSIVE MIXTURES ARE PROVIDED, BASED ON TRIMETHXXX OLETHANE TRINITRATE AND AN INORGANIC NITRATE, HAVING A HXX RATE OF DETONATION AND DOOS SENSITIVITY DUE TO THE USE XX HOT INORGANITIVE NITRATE IN FORMULATING THE EXPLOSIVE. A PROCESS ALSO IS PROVIDED FOR PREPARING SUCH EXPLOSXXX MIXTURES, BY MIXING THE INORGANIC NITRATE WITH THE METHYOLETHANE TRINITRATE AT A TEMPERATURE WITHIN RANGE FROM ABOUT 100* TO ABOUT 150*F. THE MIXING XX XX BE CARRIED OUT IN THE PRESENCE OF A SMALL AMOUNT OF WAXXX TO FACILITATE THE BLENDING AND CONTROL RATE OF DETONATIXX WITHOUT AFFECTING SENSITIVITY.

Description

3,580,751 Patented May 25, 1971 3,580,751 TMETN-INORGANIC NITRATE EXPLOSIVES BLENDED WITH HOT INORGANIC NITRATE George L. Griflith, Coopersburg, Pa., assignor to Commercial Solvents Corporation, Terre Haute, Ind. No Drawing. Filed Oct. 7, 1968, Ser. No. 765,616 Int. Cl. C06b 19/02 US. Cl. 149-38 8 Claims ABSTRACT OF THE DISCLOSURE Explosive mixtures are provided, based on trimethylolethane trinitrate and an inorganic nitrate, having a high rate of detonation and good sensitivity due to the use of hot inorganic nitrate in formulating the explosive.

A process also is provided for preparing such explosive mixtures, by mixing the inorganic nitrate with the trimethylolethane trinitrate at a temperature within the range from about 100 to about 150 F. The mixing can be carried out in the. presence of a small amount of water, to facilitate the blending and control rate of detonation, without atfecting sensitivity.

This invention relates to explosive mixtures comprising trimethylolethane trinitrate and ammonium nitrate or other inorganic nitrate, having a high rate of detonation and good sensitivity due to the use of hot inorganic nitrate in formulating the explosive, and to a process for manufacturing such explosive mixtures by blending the trimethylolethane trinitrate with ammonium nitrate at a temperature within the range from about 100 to about 150 F., optionally, in the presence of water in an amount less than about Trimethylolethane trinitrate is a liquid explosive having a high rate of detonation and a low sensitivity. It has found use in blending with other explosive sensitizers of high sensitivity, so as to make them safer to handle, without, however, reducing the sensitivity of the other explosive sensitizer to initiation by a detonator, as disclosed in US. Pat. No. 3,344,005, patented Sept. 26, 1967, to Bronstein and Griffith. However, the sensitivity of trimethylolethane trinitrate is such that it has not come into widespread use except in admixture with other explosive sensitizers.

In accordance with the invention, trimethylolethane trinitrate explosive mixtures are prepared, based on an inorganic nitrate oxidizer and trimethyolethane trinitrate as the principal if not the only explosive sensitizer. These explosive compositions have a high rate of detonation and good sensitivity because of the use of hot inorganic nitrate in formulating the explosive.

It has been determined in accordance with the invention that if trimethylolethane trinitrate and the inorganic nitrate are blended at a temperature within the range from about 100 to about 150 F., the resulting explosive mixture has a considerably higher rate of detonation than a mixture of the same composition blended at normal atmospheric temperature, and a good sensitivity.

No explanation can be offered for this remarkable effect of mixing temperature on the sensitivity and rate of detonation of the resulting explosive mixture. Evidently the mixing temperature has an effect on the physical condition of the trimethylolethane trinitrate and the inorganic nitrate in the resulting explosive mixture, resulting perhaps in a more intimate blending of the components. It is also possible that at the elevated temperatures a chemical or molecular association may occur. Whatever the reason, the effect on sensitivity and rate of detonation is striking and unmistakable.

The explosive mixtures of the invention are best formulated as dry or dry-appearing particulate mixtures, which can contain up to 5% water. In particulate mixtures, the trimethylolethane trinitrate although a liquid is wholly absorbed on the solid particles of inorganic nitrate and any other solid components that may be present. Water in an amount in excess of about 1% decreases rate of detonation, but may increase sensitivity and explosive power. Therefore, control of the amount of water affords an opportunity to control rate of detonation, sensitivity, and explosive power. Consequently, the explosive mixtures of the invention can also be formulated as slurn'es or gels, in which the amount of water is more than is absorbed by the solid ingredients, and is enough to slurry the mixture, and can be as much as about 30% by weight, preferably from about 5 to about 25% by weight.

Any inorganic nitrate can be employed as the oxidizer in the compositions of the invention. Ammonium nitrate is the nitrate normally used. However, other inorganic nitrates can be employed, alone or in admixture with the ammonium nitrate. Nitrates of the alkali and alkaline earth metals, such as sodium nitrate, potassium nitrate, calcium nitrate, strontium nitrate, and barium nitrate, are exemplary inorganic nitrates. Mixtures of ammonium nitrate with alkali and/ or alkaline earth metal nitrates in proportions within the range from about 25 to about 95% of ammonium nitrate, and from about to about 5% of the other nitrates, are preferred in many instances, because of their high explosive power. Compositions based on ammonium nitrate as the sole inorganic nitrate are also preferred because of their high power.

Mill and prill inorganic nitrates are quite satisfactory. The inorganic nitrate can be fine, coarse, or a blend of fine and coarse materials.

'In addition to the trimethylolethane trinitrate and the inorganic nitrate, which are the essential ingredients, the explosive mixtures of the invention can include one or more fuels, such as a metal fuel, or a carbonaceous fuel, or both. Illustrative of particulate metals, for example, are aluminum powder, flake aluminum, atomized aluminum, ferrophosphorus, ferromanganese, and ferrosilicon. Aluminum is a preferred fuel, because it tends to increase rate of detonation. A metal fuel when present will usually comprise from about 0.5 to about 30% of the mixture.

Useful carbonaceous materials are powdered coal, coal dust, charcoal, bagasse, dextrin, starch, wood meal, flour, bran, pecan meal or similar nutshell meals, and paraffin and petroleum oil. The carbonaceous fuel when present usually comprises from about 0.5 to about 30% of the mixture. Mixtures of such fuels can also be used in amounts within the range from about 0.5 to about 30%.

Sulfur can also be added. An amount of from about 0.5 to about 5% can increase the rate of detonation.

Stabilizers can be included in an amount within the range from about 0.1 to about 2% of the composition. Zinc oxide, ethyl centralite, diphenylamine, carbazole, calcium carbonate, aluminum oxide and sodium carbonate are useful stabilizers.

Liquid carbonaceous fuels such as petroleum in small amounts can reduce rate of detonation and in larger amounts, in addition, can increase sensitivity and explosive power. If these effects be not desired, a solid carbonaceous fuel should be used.

The relative proportions of inorganic nitrate and trimethylolethane trinitrate as well as any additional explosive sensitizers will depend upon the sensitivity and ex plosive effect desired, and are not critical. These in turn are dependent upon the particular nitrate or nitrates used. For optimum effect, the inorganic nitrate is used in amounts within the range from about 50 to about 90%, and the total explosive sensitizer including the trimethylolethane trinitrate in an amount within the range from about 10 to about 50%. The preferred ratio of nitrate to total explosive sensitizer is from about :1 to about 2:1. However, from about 35 to about 75% inorganic nitrate, and from about 25 to about 65% explosive sensitizer, give quite satisfactory results in the explosive mixtures of the invention.

The sensitizing effect of the hot inorganic nitrate during the blending of the explosive compositions is found with the trimethylolethane trinitrate, but not with the other liquid explosive sensitizers, so far as is presently known. Consequently, the trimethylolethane trinitrate is the major, if not the only, explosive sensitizer, and preferably comprises at least 90% of the explosive sensitizer that is present. However, small amounts of other explosive sensitizers can be used, up to a maximum of 25% of the total explosive sensitizer, of which dinitrotoluene, trinitrotoluene, pentaerythritol tetranitrate, pentolite (an equal parts by weight mixture of pentaerythritol tetranitrate and trinitrotoluene), cyclonite (RDX), Composition B (a mixture of up to 60% RDX, up to 40% TNT, and 1 to 4% wax), cyclotol (Composition B without the wax), nitrostarch, nitrocellulose, tetryl, smokeless powder, and carbine ball powder are exemplary. Nitrocellulose is of particular interest in the formulation of gels, as is described below.

For some purposes, the compositions of the invention can be formulated as slurries, using an inert liquid such as water as the suspending liquid. Petroleum oil affects rate of detonation, sensitivity and explosive power, and if it is used as the slurrying liquid, these effects must be taken into account. The amount of liquid that is used is more than is absorbed by the solid ingredients, and sufiicient to produce a slurry. The slurry can have any desired consistency, from a thin, readily flowable material, to a viscous material of a semi-solid consistency. As little as 5% liquid may suffice. Usually, not more than 30% liquid need be used.

In order to prevent large amounts of unabsorbed liquid from decreasing the consistency unduly, a liquid-soluble or liquid-dispersible thickener can be added to take up the liquid. The particular material employed will depend upon the liquid that is used, water-soluble or water-dispersible thickeners being used when water is the liquid, and oilsoluble or oil-dispersible thickeners being used when the oil is the liquid. Various gums, such as guar gum and crosslinked guar gum, can be used, as well as carboxymethylcellulose, methyl cellulose, psyllium seed mucilage, polyacrylamide, and pregelatinized starches, such as Hydroseal 3B, as well as silica aerogels, finely-divided silicas, inorganic gelling agents such as alumina, attapulgite, bentonite, and like materials.

The explosive mixtures of the invention are prepared by blending in a mixing vessel equipped with a heating jacket for heating the components to a temperature within the range from about 100 to about 150 F. The trimethylolethane trinitrate and inorganic nitrate oxidizer are added to the mixer, and mixing then effected at a temperature within the stated range. Water can be added to facilitate the blending; usually, for this purpose, no more than from 0.5 to 5% is required. It is not necessary to heat the ingredients beyond the time required to ensure thorough mixing, from about fifteen minutes to about onehalf hour.

It is desirable to blend the trimethylolethane trinitrate and the inorganic oxidizer under these conditions without the presence of the other explosive ingredients, so as to ensure an intimate association of the trimethylolethane trinitrate and inorganic nitrate. Since, however, the trimethylolethane trinitrate and inorganic oxidizer usually by far compose the major proportion of the composition, in order to shorten the time of mixing, minor amounts of any other explosive ingredients that are to be present can also be added at the same time. These additional components comprise the fuel, the stabilizer, and any additional explosive sensitizers. Alternatively, after mixing of the trimethylolethane trinitrate and inorganic oxidizer is complete, the other explosive ingredients can be added and thoroughly blended with the mixture. In the case of slurries, the slurrying with the mixture. In the case of slurries, the slurrying liquid is not added in an amount to slurry the mixture (it can be added in an amount to facilitate the blending) until after the trimethylolethane-trinitrateinorganic nitrate have been mixed.

The base explosive mixture of the invention, composed of trimethylolethane trinitrate, inorganic nitrate, and petroleum oil, can be formulated to form a variety of explosives, including dry particulate mixes, such as permissible explosives, and gels, such as gelatin dynamites, ammonia dynamites, and ammonia gels. Various types of formulations are illustrated in the examples.

The compositions of the invention are particularly useful in the form of explosive gels of the trimethylolethane trinitrate in combination with nitrocellulose. The nitrocellulose and trimethylolethane trinitrate are combined with a volatile nitroparaflin solvent in a sufiicient amount to dissolve the nitrocellulose and the trimethylolethane trinitrate. The solvent is then removed from the resulting composition, and as this is done, the solution thickens, and a gel of the trimethylolethane trinitrate and nitrocellulose is obtained eventually. This gel composition is then formulated with additional explosive ingredients, including hot inorganic nitrate, and any other inorganic oxidizers, other sensitizing explosives, and fuels, as described above, and can be brought to any desired consistency or physical condition.

Any type of nitrocellulose can be employed in the formulation of these gels. A fully nitrated trinitrocellulose has the highest nitrogen content (14.14% nitrogen) but the commercially available trinitrocelluloses having from 13.5 to 14% nitrogen are quite satisfactory. Any nitrocellulose having from 0.5 to 3 nitro groups per anhydroglucose unit of the cellulose can be employed, with excellent results. The preferred nitrocelluloses have from about 8% to about 14.14% nitrogen.

The amount of nitrocellulose can be varied over a wide proportion, according to the sensitivity and consistency desired.

The nitroparaflin employed has an effect on the consistency of the final gel, but the relative proportions of trimethylolethane trinitrate and nitrocellulose do. Inasmuch as the trimethylolethane trinitrate is a liquid, and the nitrocellulose is a solid, the larger the proportion of trimethylolethane trinitrate, the greater the tendency of the final gel to be a thick, semi-fluid, thixotropic or soft gel. Very hard gels can be obtained employing a large proportion of nitrocellulose. In general, the proportions of trimethylolethane trinitrate and nitrocellulose required for a gel of given hardness are best determined by trial and error, because the hardness of the gel depends to a considerable extent upon the nitrogen content of the nitrocellulose.

Satisfactory hard explosive gels are obtained, of high sensitivity and adequate explosive power, when the composition contains from about 10 to about 60 parts of nitrocellulose and from about 40 to about parts of trimethylolethane trinitrate. Soft gels are obtained when the nitrocellulose proportion is from 0.2 to parts, and trimethylolethane trinitrate is from 99.8 to 90 parts. Thus, the proportion of trimethylolethane trinitrate can be varied to a considerable extent, and any proportion within the range from about 40 parts to about 99.8 parts of trimethylolethane trinitrate to from about 0.2 part to about 60 parts of nitrocellulose can be used.

The higher the proportion of nitrocellulose, the higher the sensitivity and explosive power of the composition. The trimethylolethane trinitrate has a desensitizing effect. In general, the upper limit on the amount of trimethylolethane trinitrate will depend upon the exposive power and sensitivity that is desired, and the lower proportion will depend upon the degree of desensitization of the nitrocellulose that is required, for the end use of the composition.

The nitroparafiin that is employed should be sufficiently volatile at atmospheric temperatures, or at a temperature below about 60 C., under vacuum, if necessary, so that it can be removed virtually quantitatively from the composition after the trimethylolethane trinitrate and nitrocellulose have been dissolved therein, so as to form the desired gel. Such nitroparaflins have from one to about six carbon atoms and one nitro group, and include nitromethane, nitroethane, l-nitropropane, 2-nitro propane, l-nitrobutane and l-nitrohexane. These nitroparafiins have a boiling point below about 150 C., but higher boiling nitroparaffins can be used, if they are removed under vacuum. They are not explosive, and can not be exploded with detonating caps, differing in this respect from the trimethylolethane trinitrate. A further distinction is their volatility, despite their high boiling point. Nitromethane, for example, the lowest molecular weight compound of this series, has a boiling point of 10l.2 C., and yet it is quantitatively volatilized from the solution on standing in the atmosphere for from eight hours to three days. The relatively high boiling point is important to the formation of a gel, because it means that the nitroparaffin is only slowly volatilized from the solutions employed as a starting material in the preparation of the nitrocellulose gels. A slow volatilization of the nitroparafiin may facilitate the formation of the final explosive gel.

The amount of nitroparaffin solvent is not critical. A sufficient amount is employed to dissolve the nitrocellulose and trimethylolethane trinitrate. Depending upon the solubility of the nitrocellulose and the trimethylolethane trinitrate, as little as by weight of the composition can be employed. There is no upper limit, inasmuch as all of the nitroparafiin solvent will eventually be removed, but there is obviously no need to employ more than is necessary to dissolve the components, since any excess nitroparaflin must also be evaporated in forming the gel, with a resultant increase in the time required to form the gel, as well as in the cost of its preparation. Thus, the upper limit is normally not in excess of about 500% 'by weight of the nitrocellulose-trimethylolethane trinitrate.

Such gels in accordance with the invention can be employed with hot inorganic nitrate oxidizer in the formation of a wide variety of explosive formulations, including gelatin dynamites, smokeless powders, permissible explo sives, and nitrocarbonitrate explosives.

Gelatin and semigelatin dynamites contain, in addition to the trimethylolethane trinitrate-nitrocellulose gel, the inorganic oxidizer and a combustible material. The following is a general formulation:

Percent by weight Gelatin dynamites can be packaged in block form by filling the solution of trimethylolethane trinitrate-nitrocellulose and any other components in the nitroparaflin solvent into containers of the desired size, and then allowing the solution to gel by removal of the solvent. This can be expedited by warming the containers in a vacuum oven. Then, after the gels have set, the containers are capped and sealed. Stick gelatin dynamites are easily prepared in this way.

Some hard gelatin dynamites can be prepared by first mixing the nitrocellulose, nitroparafiin, and trimethylolethane trinitrate, and then allowing the nitroparaffin to evaporate, forming a viscous liquid or gel. The viscous liquid or gel is then blended with the hot inorganic oxidizer, fuels and any additional sensitizers desired forming a damp granular mixture, in which the liquid or gel is coated or absorbed on the solid components. The mixture is then packaged in cartridges, using conventional dynamite pack machines.

Smokeless powders are in particulate form, and are based on the trimethylolethane trinitrate-nitrocellulose gel as one component, in combination with the usual components to control the rate of burning. The types of smokeless powders that can be formulated, using the gels and hot inorganic nitrate in accordance with the invention, include double base powders and ball grain powders. Typical general formulations are as follows:

Double base powder: Percent by weight Polyol polynitrate 5-60 Nitrocellulose 5-95 Inorganic oxidizer (blended hot) 0-50 Combustible material or fuel 0-5 Ball grain powder:

Polyol polynitrate 5-60 Nitrocellulose -40 Inorganic oxidizer (blended hot) 0-20 Combustible material or fuel 0-15 Gelled pellets of smokeless powder can be prepared by stirring the solution composed of trimethylolethane trinitrate, nitroparafiin solvent and nitrocellulose rapidly with hot water, heating the mixture at an elevated temperature in order to remove the nitroparafiin and set the gel particles, While at the same time dispersing the solution into small droplets, so that the gel particles are formed in finely-divided dispersed form in the water. The particles can then be separated from the water by screening and drying. The resulting composition is a pelleted smokeless powder, the size of whose pellets depends upon the degree of dispersion and the mesh size of the screen through which the composition is passed.

The explosive mixtures of the invention are sufliciently sensitive so that frequently they can be detonated with an ordinary initiator or blasting cap. However, when not, the compositions can be fired with the aid of a small booster charge. Combinations of the explosive mixtures as powders together with an initiator and/or booster in the same container can be prepared and marketed as a combined blasting agent. The explosive compositions and the booster or initiator can be separately packaged as a composite in a single container, and can also be marketed in this form. Any conventional initator or booster charge available in the art can be employed. Pentaerythritol tetranitrate, pentolite, tetryl and cyclonite, preferably in cast form, are exemplary booster charges.

The following examples in the opinion of the inventor represents the best embodiments of the invention.

The power of the explosives of the examples was determined using the standard tests for determining sensitivity, density, rate of detonation, and stick weight.

EXAMPLES 1 TO 4 A group of eight compositions was prepared, having the formulation set out in Table I. Four were mixed cold,

TABLE 1 Parts by weight Control Example Control Example Example Example Mixing temperature, F 70 130 70 130 130 130 Composition:

Trimethylolethane trinitratc 15. 15. 00 15. 00 15. 00 15. 00 15. 00 Ammonium nitrate ground 80. 00 80. 00 80. O0 Ammonium nitrate, grained 80. 00 80. 00 80. 00 Nut meal 5. 00 5. 00 5. 00 5. O0 5. 00 5. 00 Sulfur 2. 00 2. 00 2. O0 2. 00 2, 00 Water 1. 00 1. 00 1. 00 1. 00 2. 00 3. 00

Total 103. 00 103. 00 103. 00 103. 00 102. 00 105. 00

Test results:

Sand density (g./cc.) 1. 06 0.955 1. 195 0. 885 0. 895 O. 975 Stick weight (g.) (1% inches x 8 inches). 148 134 166 125 128 137 Sensitivity (1 inch x 4 inches) Rate of detonation (1% inches x 8 inches) (meters/second) 2, 329 2, ll 2, 230 2, 252 2, 102 2, 074

1 No. 1 cap. 2 cap. 3 No.6 cap.

Control formulations A and B are to be compared with Examples 1 and 3, respectively. The four compositions have identical formulations, and difier only in the temperatures at which the formulations were mixed.

In all cases, the trimethylolethane trinitrate and amamples 5 and 6 compared to Controls E and F show the increase in rate of detonation (as comparable composition densities) that is obtained when ammonium nitrate is mixed with the trimethylolethane trinitrate at 130 F. instead of at 70 F. The sensitivity of Examples 5 and 6 monium nitrate were mixed thoroughly for fifteen minwas good. utes at the temperature indicated in Table I. The remaining ingredients of the compositions were then added, and thoroughly blended in the mixture in another fifteen minutes of mixing.

A comparison of Control A with Example 1 and of Control B with Example 2 shows that the compositions mixed hot had a higher rate of detonation than the compositions mixed cold, which is the more significant because of the lower density of the mixed hot compositions. Consequently, the stick weights were less, but even so, Examples 1 and 2 were superior to Controls A and B. Examples 1 and 2 also had better sensitivity than the controls; in fact, the improvement in sensitivity between Control B and Example 2 (No. 6 v. /2 cap) is quite remarkable. Mixing temperature, F n 130 130 130 Examples 3 and 4 show the efiect of water in excess 25 EXAMPLES 7 TO 9 A group of three formulations was prepared, containing flake aluminum as a metal fuel in addition to the carbonaceous fuel and the other components. The ammonium nitrate, trimethylolethane trinitrate and other ingredients were all mixed together at the temperature indicated for twenty minutes. These compositions had the following formulation:

35 TABLE III Parts by weight Example Example Example 7 8 9 Composition:

of 1% on rate of detonation, in compositions having com- Trimethylolethane trlni trate i 15, 0o 15. 0o 15, 00 parable densities and stick weights. The Example 3 comgmiii u r n figgtifi i i R1ZT 31%?) 35% %33 position has a considerably lower rate of detonation than Nut meal 5. 00 5100 5100 Example 2. Example 4 shows that increasing water to 3% Water tfl 00 -g further decreases rate of detonation. It is evident from a Total 103. 00 103.00 105.00 comparison of Examples 1 and 2 with 3 and 4 that in- Test results: corporating an amount of water exceeding 1% provides Sand density (g./cc.) 0.885 0. 992 0. 94 a way of obtaining a lower rate of detonation. 125 139 E MP E 5 AND 6 21 .302.12.232.ilhiilttsrr 0 inches) (meters/second) 2, 749 2, 782 2, 364

A group of four explosive mixtures was prepared having the formulation shown below. 16

TABLE II Parts by weight Control Example Control Example Mixing temperature, F 130 70 130 Composition: I

Trimethylolethane trlnitrate Y 15. 00 15. 00 15. 00 15. 00 Ammonium nitrate, grained- 80. 00 80. 00 80. 00 80. 00 5. 00 5. 00 5. 00 5. 00 Sulfur 2. 00 2. 00

Total 100. 00 100. 00 102. 00 172. 00

Test results:

Sand density (g./cc.) 0. 955 0. 955 0. 955 0. 955 Stick weight (g.) (1% inches x 8 inches) 134 134 134 134 Sensitivity (1 inch x 4 inches) Rate of detonation (1% inches x 8 inches) (meters/second) 2, 488 2, 556 2, 584 2, 651

In preparing these formulations, the trimethylolethane 70 trinitrate, ammonium nitrate, nut meal and sulfur were all mixed together at the temperature indicated in the Table.

Example 6 as compared to Example 5 shows that the It is evident from a comparison of Examples 7, 8 and 9 with Examples 1, 2 and 4 that the addition of aluminum considerably increased the rate of detonation, even when water was present. Adjustment of the relative proportions of aluminum and water makes it possible to obtain any addition of sulfur increases the rate of detonation. Exdesired rate of detonation, for these compositions.

9 EXAMPLES 10 TO 12 A group of six formulations was prepared, having the following composition.

10 EXAMPLES 13 TO 15 Three formulations were prepared, having amounts of trimethylolethane trinitrate ranging from 10% to 20%.

TABLE IV Parts by weight Control Example Control Example Control Example G 10 H 11 I 12 Mixing temperature, F 70 130 70 130 70 130 Composition:

Trimethylolethane trinitrate 5. 5. 00 10. 00 10. 00 15. 00 15. 00 Ammonium nitrate, grained. 95. 00 95. 00 85. 00 85. 00 80. 00 80. 00 Nut meal 5. 00 5. 00 5. 00 5. 00

TotaL- 100. 00 100. 00 100. 00 100. 00 100. 00 100. 00

Test results:

Sand density (g./cc.) 0.88 0.88 0.885 0. 885 0. 955 0.955 Stick weight (g.) (1% inches X 8 inches) 123 123 125 125 134 134 Sensitivity (1 inch x 4 inches) Rate of detonation (1% inches x 8 inches) (meters/second)-.. 1, 412 1, 300 2, 102 2, 074 2, 515 2, 556

1 5-1 cap. 2 N o. 1 cap. 8 cap.

Each of these formulations was mixed fifteen minutes at the temperature indicated in the table, with the trimethylolethane trinitrate, ammonium nitrate and nut meal all being added together before mixing.

It is evident from the results that in order to obtain the beneficial effect of mixing at an elevated temperature, it is important to have at least 10% by weight of trimethylolethane trinitrate. At the level of 5% trimethylolethane trinitrate, the rate of detonation is very low, and there is no advantage in hot mixing. At the 10% level, the rates of detonation of the hot mixed and cold mixed material are nearly equal, and at the level, the hot mixed material has a higher rate of detonation than the cold mixed material. This demonstrates that the effect of the mixing is due to some interaction between the trimethylolethane trinitrate and the ammonium nitrate,

' and not due to an effect on the ammonium nitrate alone,

because if this were the case, the increased rate of detonation would also have been observed in Example 10. r

All three compositions of the invention had good sensitivity.

These formulations had the following composition.

TAB LE V Parts by weight Example Example Exarnpha 13 14 15 Mixing temperature, F 120 120 3 5 Composition:

Trimethyloiethane trinitrate 10.00 15.00 20. 00 Ammonium nitrate grained 75. O0 70. 00 59. Sodium nitrate 10. 00 10. 00 10. 00 Alrneg -30 aluminum (granules) 1. 00 1. 00 2. 00 Flake aluminum 1. 00 1. O0 Sulfur 2. 00 2. 00 2. 50 40 Wheat flour 5. 00 Water 1. 00 1.00 1.00

Total 100. 00 100. 00 100. 00

Test results:

Sand density (g./cc.) 0.935 0.975 1. 23 Stick weight (g.) (1% inches x 8 4 5 inches) 127 132 165 Sensitivity (1 inch x 4 inches) Rate of detonation (1% inches x 8 inches) (meters/second) 2, 200 2, 425 2, 482

cap.

These compositions had good rates of detonation. and good sensitivities.

EXAMPLES 16 TO 19 A group of four formulations was prepared. These formulations were as follows:

TABLE VI Parts by weight Example Example Example Example 16 17 18 19 Mixing temperature, F 120 120 120 Composition:

Trimethylolethane trinitrate- 20. 00 20. 00 20. 00 20. 00 Ammonium nitrate, grained- 63. 00 63. 00 63. 00 63. 00 Sodium nitrate, mill 10. 00 10. 00 10. 00 10. 00 Flake aluminum 2. 00 2. 00 2. 00 2. 00 Wheat flour 5. 00 5. 00 5. 00 5. 00 Oil No. 5 0. 30 1. 00 2. 00

Total 100. 00 100. 30 101. 00 102. 00

Test results:

Sand density (g.lcc.) 1.19 1.19 1.19 1.19 Stick weight (g.) (1% inches x 8 inches) 160 160 160 Sensitivity (1 inch x 4 inches Rate of detonation (1% inches x 8 inches) (meters/sec0nd) 4, 112; 3, 908 3, 867 2, 866 1, 954

1 cap. 2 No. 6 cap.

The trimethylolethane trinitrate, sodium nitrate and ammonium nitrate were blended with the other ingredients simultaneously, and the mixing time at 120 F. was onehalf hour. The results show the effect of oil on rate of detonation of aluminum-containing formulations. At com- 12 the aluminum particles should be relatively fine, in the range of -325 mesh up to -l20 mesh (flakes), for a high rate of detonation.

In the claims and in the specification, all proportions, percentages and parts are by weight.

parable densities, rate of detonation is reduced, without Having regard to the forgoing disclosure, the follow affecting sensitivity, until 2% by weight of oil is added. ing is claimed as the inventive and patentable embodi Thus, adjustment of the relative proportions of aluminum ments thereof: Oil makes it POssible to Vary Tam of detonation as 1. A process for forming a trimethylolethane trinitrate deslredexplosive composition having a high rate of detonation EXAMPLES TO 24 and good sensitivity, comprising blending trimethylolethane trinitrate and an inorganic nitrate oxidizer at a A group of five formulations was prepared u ing alumitemperature within the range from about 100 to about 1mm in v rio powdered particle forms, ranging from 150 F., until an intimately associated mixture is formed powder to atomiz d aluminump e 6 i included, 5 in which the trimethylolethane trinitrate is wholly abfor comparison with mill flake aluminum. These formulasorbed on the solid particles of inorganic nitrate oxidizer. tions had the following composition: 2. A process in accordance with claim 1, in which the TABLE VII Parts by weight Example 16 Example 20 Example 21 Example 22 Example 23 Example 24 Mixing temperature, F

Composition:

Trimethylolethane trinitrate Ammonium nitrate Sodium nitrate- Wheat flour Mill flake aluminunu Almeg 90-18 aluminum powder, 18-19 mesh. M- aluminum powder, 30 mesh Atomized 12120 aluminum 100 P aluminum powder, 100 mesh Alcoa 606 aluminum fine flake Total 100. 00 100. 00 100. 000 100. 00 100. 00 100. 00

Test results: Sand density (g./cc.) .a 1. I9 1. 11 1. l1 1. ll 1. ll 1. 19 Stick weight (g.) (1% inches x 8 inches) 160 150 150 150 150 160 Sensitivity (1 inch x 4 inches) (r) (1) (1) Rate of detonation (1% inches x 8 inches) (meters/second) 4, 112; 3, 908 3, 503 3, 105 3,111 3, 427 3, 750

1 Cap.

These formulations were mixed at 130 F. for one-half hour. The trimethylolethane trinitrate and ammonium nitrate and sodium nitrate were blended with the alumimum and the wheat flour, and the entire mixture was heated at 130 F. for the full mixing time.

All six compositions had good sensitivity, and exceptionally high rates of detonation.

EXAMPLE 25 A trimethylolethane trinitrate-nitrocellulose gel was prepared by dissolving 4 parts of nitrocellulose (12.5% N) in 120 parts of nitromethane. To this was added with stirring 16 parts of trimethylolethane trinitrate. The mixture was then spread in a thin layer in a tray, allowing the nitromethane to evaporate, leaving a pliable, clear gel.

A gelatin dynamite was prepared from this gel, having the following formulation:

The ammonium nitrate was brought to 130 F. and mixed hot with the gel. The remaining ingredients were then mixed in. This composition had a good sensitivity, a high density, and a low rate of detonation.

It is evident that the form of the aluminum has a considerable effect upon the rate of detonation. The highest rate of detonation is obtained with flake aluminum, and the lowest with atomized aluminum. This shows that blending is carried out in the presence of water, in an amount not exceeding about 5%.

3. A process in accordance with claim 1, wherein the inorganic nitrate is ammonium nitrate.

4. A process in accordance with claim 1, wherein the inorganic nitrate is a mixture of ammonium nitrate and sodium nitrate.

5. A process in accordance with claim 1, which includes blending a carbonaceous fuel with the blend of inorganic nitrate and trimethylolethane trinitrate in an amount of from about 0.5 to about 30%.

6. A process in accordance with claim 1, which includes blending a metal fuel with the blend of the inorganic nitrate and trimethylolethane trinitrate in an amount of from about 0.5 to about 30%.

7. A process in accordance with claim 1, wherein the blending is continued for from fifteen minutes to onehalf hour.

8. A trimethylolethane trinitrate explosive composition having a higher rate of detonation than a cold-mixed explosive of like composition, and good sensitivity, comprising an intimately associated hot-mixed mixture of an inorganic nitrate oxidizer and trimethylolethane trinitrate as the principal explosive sensitizer prepared by the process of claim 1.

References Cited UNITED STATES PATENTS 2,821,466 1/1958 Russel 149-8 3,344,005 9/1967 Bronstein et al. 14988X 3,423,256 1/ 1969 Grifiith 14947X 3,489,623 1/1970 Griffith et a1. 14991X BENJAMIN R. PADGETT, Primary Examiner S. J. LECHERT, JR., Assistant Examiner US. Cl. X.R.

5222 33 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,580,751 Dated Mag 25, 1971 George L. Griffith Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

' I Column 4, line 58, "an" should be --no-. Column 5, line 13, "exposive" should be --explosive--. Column 6, line 60, "initator" should be -initiator-. Column 7, Table II, Example 6, line 65, 172.00" should be --102.00--. Column 8, Table III, Example 8, line 44, "1.00" should be --2.00-; line 46, "103.00" should be IO LOO Example 9, line 42, "15,00" should be --15.00--. Column 12, line 65, Patent No. 2,821,466 "Russel" should be ---Russell--. I n

Signed and sealed this 25th day of January 1972.

(SEAL Attest: v..

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attagting Officer Commissioner of Patents