US3208890A - Gelatinized explosive - Google Patents

Description

United States Patent 3,208,890 GELATINIZED EXPLOSIVE Carl Torsten Edlund and Gustav Allan Wetterholm,

Gyttorp, Sweden, assignors to Nitroglycerin Aktiebolaget, a company of Sweden No Drawing. Filed Feb. 27, 1963, Ser. No. 261,521

Claims priority, application Sweden, Feb. 28, 1962,

5 Claims. (Cl. 149-47) The present invention generally relates to a novel explosive of the gelatinized type having improved physiological acceptance and a low sensitivity to impact. More specifically the present invention pertains to an explosive comprising an oxygen-delivering inorganic salt and an explosive oil consisting of propylene-glycol dinitrate or a mixture of propylene-glycol dinitrate with no more than 50 percent of nitroglycerine.

glycol dinitrate unless one or the other of these individual compounds is especially intended) are known substances having properties which render them suitable as explosives.

Both compounds have been suggested as ingredients in explosive along with oxygen-delivering inorganic salts. Such explosives are as a rule highly insensitive to impact. Due to being considerably under-balanced with respect to oxygen, they have not, however, obtained any practical importance up to the present.

It is known that propylene-glycol dinitrate-containing highly underbalanced explosives are highly insensitive to impact. It is also known that highly overbalanced as well as underbalanced explosives are generally insensitive to impact, but that the sensitivity to impact will increase on oxygen-balancing, so that mixtures of considerable sensitivity will be obtained. It has now surprisingly been found that propylene-glycol dinitrate-containing explosives can be produced which maintain their high insensitivity to impact even after oxygen-balancing.

In comparison with explosives containing nitroglycol (the dinitrate of ethylene glycol) as an additive to nitroglycerine, our novel oxygen-balanced explosives present considerable advantages. The use of nitroglycol is, as known, connected with physiological drawbacks. When admixed with nitroglycerine, the nitroglycol will increase the vasodilatory effect on the blood veins of man which is particularly manifested as headache and indisposition. Another reason why mixtures of nitroglycol with nitroglycerine are physiologically disadvantageous is ascribed to the poisonous effect of the nitroglycol itself. In this connection, reference is made to the cases of sudden collapses which will frequently happen among workers of explosive factories who come into contact with this substance, usually a couple of days after leaving work. Pro pylene-glycol dinitrate-containing explosives are decidedly more acceptable from a physiological viewpoint and do not possess the disadvantages above referred to.

The better physiological acceptability of propyleneglycol dinitrate may be explained by the fact that the substance has relatively little solubility in the blood of man. The solubility of the propylene-glycol dinitrates in water, as compared with nitroglycerine and nitroglycol (the dinitrate'of ethylene glycol), is evident from the following table. The values set forth relate to the solubility at 20 C.

Percent Nitroglycerine 0.18 Nitroglycol 0.63 1-,3-propylene-glycol dinitrate 0.24 1,2-propylene-glycol dinitrate 0.13

3,208,890 Patented Sept. 28, 1965 THE PRESENT INVENTION The present invention relates to an explosive having an improved physiological acceptance and a low sensitivity to impact, consisting of or containing propylene-glycol dinitrate, and one or more inorganic oxygen-delivering salts. One important characterizing feature of the explosive according to the invention is that the oxygen-delivering inorganic salt or salts are present in a suflicient amount to substantially oxygen-balance the explosive.

Because the explosives according to the invention possess a combination of high insensitivity to impact with an excellent physiological acceptance, they represent a valuable advance in the field of explosives.

A further feature of the invention is that the explosive contains 370% propylene-glycol dinitrate and 10-95% oxygen-delivering inorganic salt.

The propylene-glycol dinitrate can either be the only liquid ingredient of the explosive oil, or it can be admixed with other liquid ingredients. If the explosive oil is a mixture of different substances, may contain up to about 50 percent of nitroglycerine. It is natural that the explosive must not contain any substantial amounts of nitro- GELATINIZING OF THE EXPLOSIVE OIL An explosive oil, consisting of propylene-glycol dinitrate or at least mainly of this substance, does not form a gel with nitrocellulose at usual temperatures. In order to attain gelatinizing, increased temperatures Will be required. In this connection, that, especially if subjected to alternating freezing and thawing, rgels produced at high temperatures will gradually release their oil. It may be noted that amounts as high as 14 percent of nitrocellulose have been suggested to obtain an acceptable gel. According to a further embodiment 'of the invention, this amount can be decreased considerably if there is added to the ex-- plosive oil an agent capable of facilitating the gelatinizing (i.e., a gelatinizing aid) in an amount of 02-10 percent, preferably 0.57 percent, based on the total weight of the explosive oil. There is thus obtained the important elfect that the explosive oil will gelatinize at normal temperatures and, furthermore, the amount 'of gelatinizing agent (nitrocellulose) which is an expensive product, can be decreased without any essential drawbacks resulting. A fully acceptable gelatinizing of propyleneglycol dinitrate can be attained by less than 8 percent of nitrocellulose in the explosive oil. Usually, only 3-5 percent is required to attain this result.

As gelatinizing aids may generally be mentioned hydrogen bond-forming substances. Such aids will be effective in proportion to their ability to form such bonds. As examples of such substances there may be mentioned:

Alc0h0ls.Aliphatic monohydric primary, secondary and tertiary alcohols, containing from 1 to 10 carbon atoms, for example methanol, ethanol, isopropylalcohol, n-propylalcohol, the butyl alcohols, the amyl alcohols, n-decanol and nonyl carbinol, aliphatic polyhydric alcohols such as ethylene-glycol, diethylene-glycol, the propylene-glycols and glycerol;

Ketones.Aliphatic ketones such as acetone, methylit has been proved the content of which may be 8 percent or less.

ethyl-ketone, methylisobutyl-ketone and up to the decanones as well as the bicyclic ketone camphor;

Esters.Esters of aliphatic alcohols with formic acid, acetic acid, and propionic acid, for example ethyl acetate and butyl acetate, polyhydric alcohols partially esterified with acetic acid or nitric acid such as the partial esters of ethylene-glycol, diethylene-glycol, the propyleneglycols and glycerol with acetic aaid and nitric acid, such as mononitroglycerine, mononitroglycol and dinitroglycerine;

Eth'ers.With lower alkyls monosubstituted ethyleneglycol and diethylene-glycol in which the lower alkyls may be methyl, ethyl, propyl and butyl, such as glycolmonomethylether and glycol-monoethylether.

Other gelatinizing aids are monoand di-nitrosubstituted derivatives of benzene and toluene. If an explosive oil, containing propylene-glycol dinitrate, is free from nitroglycerine, the latter substance may be added as a gelatinizing aid up to amounts of 8 percent, for example.

THE OXYGEN-DELIVERING INORGANIC SALT TABLE Oxygeitbalaneed mixture Oxygen-deliveriug-salt Percent salt Percent Ammonium nitrate NH4NO3 Sodium nitrate NaNO;

Potassium chlorate K Sodium chlorate NaClO3 Potassium perchlorate KClO4 Ammonium perchlorate NH4ClO4 OTHER INGREDIENTS The explosive according to the invention may contain high brisant explosives such as trotyl, pentyl, hexogen etc. Furthermore, it may contain usual oxygen-consuming substances such as saw duct, flours of different kinds and metal powders, and usual fillers such as kieselguhr.

TYPES OF EXPLOSIVE INVOLVED The gelatinized explosives according to the invention may be produced'in different forms, namely, as powders or in plastic or semiplastic conditions. These explosives may also contain as an ingredient finely divided metals This especially applies to powder explosives, but also the plastic and semiplastic explosives may contain low amounts of finely divided metals.

EXAMPLES The following examples are illustrative of preferred embodiments of the present invention. It should be understood that these examples are not intended to limit the invention and that obvious changes may be made by those skilled in the art without changing the essential characteristics and the basic concept of the invention.

Example 1 A plastic explosive was made up by mixing together the following ingredients:

Gap test (24 mm. cartridge), mm. at 20 C. l30 Impact sensitivity test according to Kast, 2 kg.

fall weight, percent detonation per cm. fall height 0/60 The mixture was prepared by first mixing together the propylene-glycol dinitrate and the nitrocellulose, whereupon the methanol was added to the mixture obtained. Gelatinizing took place satisfactorily without heating the mixture. Then the salt mixture was added and finally the wood flour together with the chalk.

Example 2 A plastic explosive was made up by mixing together the following ingredients:

g. 1,2-propylene-glycol dinitrate 37.0 Nitrocellulose 1.4 Ethyl diglycol 0.4 Ammonium nitrate 41.3 Sodium nitrate 18.85 Cork flour 1.0 Chalk 0.05

The oxygen-balance of the explosive was +40%.

The properties of the explosive were the following:

Volume weight 1.45 Gap test (25 mm. cartridge), mm. at 20 C. -180 Impact sensitivity test according to Kast, 2 kg.

fall weight, percent detonation per cm. fall weight 0/06 Example 3 A plastic explosive was made up by mixing together the following ingredients:

g. 1,2-propylene-glycol dinitrate 37.5 Nitrocellulose 1.3 Methanol 0.4 Camphor 0.4 Ammonium nitrate 41.1 Sodium nitrate 18.75 Wood fiour 0.5 Chalk 0.05

The oxygen-balance of the explosive was +33%.

The properties of the explosive were the following:

Volume weight 1.49 Gap test (25 mm. cartridge), mm. at 20 C. 80-100 Impact sensitivity test according to Kast, 2 kg.

fall weight, percent detonation per cm. tall weight 0/ 60 In the following table, there are listed further examples for the composition of the explosive according to the invention and an example of a composition, containing ethylene-glycol dinitrate, given for purpose of comparison.

TABLE Powder Semiplastic explosive explosive with nitrowith nitrocellulose cellulose 1,2-propylene-glycoldinitrate. 6. 3 23. Dinitrotoluene 2. 0 Methylethy1ketone 0. 5 Trotyl 11. 0 Nitrocellulose 0. 1 Ammonium nitrate 69. 1 Sulfur Sodium nitrate. 7. 0 Aluminiunn 2. 0 Wood flour... 2. 7 Kieselguhr- 1. 1 Paraffin 0. 2

Oxygen-balance, percent +0. 6 +1. 8 Properties:

Volume weight 1. 1 1. 46 Detonation velocity, kITL/S 4. 7 2. 75 Gap test (25 mm. cartridge) mm. at

20 C 0-10 0-10 Impact sensitivy test according to Kast, by 2 kg. fall weight, percent detonation per cm. tall height 0/60 0/60 Plastic explosives- With propylene-glycol With dinitrate ethyleneglycoldinitrate 1,2-propylene-glyco1 dinitrate 37. 0 54. 0 30. 0 1,3

' 30. 0 Nitroglycerine 7. 5 2. 0 20. 0 Ethylene-glycol dinitrate 20. 0 Dinitrotoluene 3. 0 3. 0 1. 0 3. 5 Nitrocellulose 1. 3 1. 3 1. 5 l. 0 1. 5 Monoacetin 0. 5 2. 0 Amrnonium nitrate. 29. 55 23. 61. 0 53. 95 Sodium nitrate 27. 6 33. 85 3. 95 Ammonium perchlorate. 40. 0 Wood flour 1. 0 1. 0 3.0 1. 0 Chalk 0. 05 0. 05 0. 05 0. 05

Oxygen-balance, percent +4. 5 +4 1 4 Properties:

Volume weight 1. 5O 1. 55 1. 45 Detonatation velocity, km./s 4. 0 3. 2 6. 1 Gap test (25 mm.

cartridge) mm. at

C 180-200 150-200 230 Impact sensitivity test according to Kast, percent detonation per cm. fall helght 0/60 0/60 0/60 0/60 10/30 As is evident from the above examples, the novel explosive according to the present invention has a very low sensitivity to impact. This is especially apparent when comparing the fall heights of the explosives according to the present invention (Examples 1 to 9) with what occurs to the nitroglycol-containing explosive according to Example 10. While in the last mentioned case, the percent of detonations amounted to 10 percent even for 300 mm. fall height, none of the nine compositions of explosives according to the present invention gave any detonation even for a fall height as high as 600 mm.

Those skilled in the chemical arts, and particularly in the art to which this invention pertains, will readily appreciate that many modifications of the basic invention set forth here are possible. For example, it would not involve invention to try closely related compounds in view of the present broad disclosure or in trying amounts different than those disclosed. All such obvious modifications would not avoid infringement under the well known doctrine of equivalents.

What we claim is:

1. A plastic explosive consisting of the following ingredients in the following amounts:

G. 1,2-propylene-glycol dinitrate 37.0 Nitrocellulose 1.3 Methanol 0.4 Ammonium nitrate 41.5 Sodium nitrate 18.75 Wood flour 1.0 Chalk 0.05

2. A plastic explosive consisting of the following in gredients in the following amounts:

G. 1,2-propylene-glyco1 dinitrate 37.0 Nitrocellulose 1.4 Ethyl diglycol 0.4 Ammonium nitrate 41.3 Sodium nitrate 18.85 Cork flour 1.0 Chalk 0.05

3. An explosive composition having an improved physiological acceptance and a low sensitivity to impact comprising as its essential ingredients:

(a) 10-95% by weight of an oxygen delivering inorganic salt,

(b) 370% by weight of an explosive oil, said explosive oil being selected from the group consisting of the dinitrate of 1,2-propylene glycol, the dinitrate of 1,3-propylene glycol, and mixtures of one of these dinitrates with up to 50% by weight of nitroglycerme,

(c) 02-10% by weight of gelatinizing aid and a gelatinizer for said explosive oil,

(d) between 0 and 2% of nitroglycol,

said oxygen-delivering inorganic salt being present in an amount to substantially oxygen balance the explosive.

4. An explosive composition according to claim 3 wherein said gelatinizer is nitrocellulose.

5. An explosive composition according to claim 3 wherein said oxygen-delivering inorganic salt is selected from the group consisting of (a) nitrates of ammonium, alkali metals and alkaline earth metals, (b) perchlorates of ammonium, alkali metals and alkaline earth metals and (c) chlorates of alkali metals and alkaline earth metals.

References Cited by the Examiner UNITED STATES PATENTS 1,213,369 1/17 Hibbert 149104 1,307,033 6/19 Barab 149-104 1,485,003 2/24 Woodbury 14947 X 1,637,726 8/27 Bergeim 14947 X 1,640,712 8/27 Moran 14995 1,879,064 9/ 32 Bryan 149104 2,481,795 9/49 Taylor et a1. 14947 2,768,073 10/56 Davidson 14948 'X CARL D. QUARFORTH, Primary Examiner. RUEBEN EPSTEIN, Examiner.

Claims (1)

1. 3. AN EXPLOSIVE COMPOSITION HAVING AN IMPROVED PHYSIOLOGICAL ACCEPTANCE AND A LOW SENSITIVITY TO IMPACT COMPRISING AS ITS ESSENTIAL INGREDIENTS: (A) 10-95% BY WEIGHT OF AN OXYGEN DELIVERING INORGANIC SALT, (B) 3-70% BY WEIGHT OF AN EXPLOSIVE OIL, SAID EXPLOSIVE OIL BEING SELECTED FROM THE GROUP CONSISTING OF THE DINITRATE OF 1,2-PROPYLENE GLYCOL, THE DINITRATE OF 1,3-PROPYLENE GLYCOL, AND MIXTURES OF ONE OF THESE DINITRATES WITH UP TO 50% BY WEIGHT OF NITROGLYCERINE, (C) 0.2-10% BY WEIGHT OF GELATINIZING AID AND A GELATINIZER FOR SAID EXPLOSIVE OIL, (D) BETWEEN 0 AND 2% OF NITROGLYCOL, SAID OXYGEN-DELIVERING INORGANIC SALT BEING PRESENT IN AN AMOUNT TO SUBSTANTIALLY OXYGEN BALANCE THE EXPLOSIVE.