3,208,890 United States Patent Office Patented Sept. 28, 1965 2 3,208,890 From the table, it is thus evident that the two propyl GELATNIZED EXPLOSIVE ene glycol dinitrates, and especially the 1,2-compound, Carl Torsten Edlund and Gustav Allan Wetterholm, Gyttorp, Sweden, assignors to Nitroglycerin Aktiebola are decidedly less soluble in water than nitroglycol, where get, a company of Sweden by they are absorbed by the blood to a less degree. No Drawing. Filed Feb. 27, 1963, Ser. No. 261,521 Claims priority, application Sweden, Feb. 28, 1962, THE PRESENT INVENTION 2,232/62 The present invention relates to an explosive having an 5 Claims. (Cl. 149-47) improved physiological acceptance and a low sensitivity to impact, consisting of or containing propylene-glycol di The present invention generally relates to a novel ex 0. nitrate, and one or more inorganic oxygen-delivering plosive of the gelatinized type having improved physio salts. One important characterizing feature of the ex logical acceptance and a low sensitivity to impact. More plosive according to the invention is that the oxygen-de specifically the present invention pertains to an explosive livering inorganic salt or salts are present in a sufficient comprising an oxygen-delivering inorganic salt and an ex amount to substantially oxygen-balance the explosive. plosive oil consisting of propylene-glycol dinitrate or a 15 Because the explosives according to the invention mixture of propylene-glycol dinitrate with no more than possess a combination of high insensitivity to impact with 50 percent of nitroglycerine. an excellent physiological acceptance, they represent a BACKGROUND valuable advance in the field of explosives. A further feature of the invention is that the explosive 1,2-propylene-glycol dinitrate and 1,3-propylene-glycol 20 contains 3-70% propylene-glycol dinitrate and 10-95% dinitrate (hereinafter simply referred to as "propylene oxygen-delivering inorganic salt. glycol dinitrate” unless one or the other of these individual The propylene-glycol dinitrate can either be the only compounds is especially intended) are known substances liquid ingredient of the explosive oil, or it can be admixed having properties which render them suitable as explosives. with other liquid ingredients. If the explosive oil is a Both compounds have been suggested as ingredients in ex mixture of different substances, it may contain up to about plosive along with oxygen-delivering inorganic salts. 50 percent of nitroglycerine. It is natural that the ex Such explosives are as a rule highly insensitive to impact. plosive must not contain any substantial amounts of nitro Due to being considerably under-balanced with respect to glycol, because otherwise the two abovementioned essen oxygen, they have not, however, obtained any practicalim tial advantages of the explosive would be lost. If nitro portance up to the present. 30 glycol is present in the explosive oil serving as the basic It is known that propylene-glycol dinitrate-containing ingredient of an explosive, the content thereof should highly underbalanced explosives are highly insensitive to preferably not exceed about 2 percent. impact. It is also known that highly overbalanced as well as underbalanced explosives are generally insensitive GELATINIZING OF THE EXPLOSIVE OL to impact, but that the sensitivity to impact will increase on oxygen-balancing, so that mixtures of considerable sensi An explosive oil, consisting of propylene-glycol dini tivity will be obtained. It has now surprisingly been trate or at least mainly of this substance, does not form found that propylene-glycol dinitrate-containing explosives a gel with nitrocellulose at usual temperatures. In can be produced which maintain their high insensitivity order to attain gelatinizing, increased temperatures to impact even after oxygen-balancing. 40 will be required. In this connection, it has been proved In comparison with explosives containing nitroglycol that, especially if subjected to alternating freezing and (the dinitrate of ethylene glycol) as an additive to nitro thawing, gels produced at high temperatures will gradu glycerine, our novel oxygen-balanced explosives present ally release their oil. It may be noted that amounts considerable advantages. The use of nitroglycol is, as as high as 14 percent of nitrocellulose have been sug known, connected with physiological drawbacks. When 45 gested to obtain an acceptable gel. According to a admixed with nitroglycerine, the nitroglycol will increase further embodiment of the invention, this amount can the vasodilatory effect on the blood veins of man which be decreased considerably if there is added to the ex is particularly manifested as headache and indisposition. plosive oil an agent capable of facilitating the gelatinizing Another reason why mixtures of nitroglycol with nitro (i.e., a gelatinizing aid) in an amount of 0.2-10 percent, glycerine are physiologically disadvantageous is ascribed 50 preferably 0.5-7 percent, based on the total weight of to the poisonous effect of the nitroglycol itself. In this the explosive oil. There is thus obtained the important connection, reference is made to the cases of Sudden col effect that the explosive oil will gelatinize at normal lapses which will frequently happen among workers of temperatures and, furthermore, the amount of gelatiniz explosive factories who come into contact with this Sub 55 ing agent (nitrocellulose) which is an expensive product, stance, usually a couple of days after leaving work. Pro can be decreased without any essential drawbacks re pylene-glycol dinitrate-containing explosives are decided Sulting. A fully acceptable gelatinizing of propylene ly more acceptable from a physiological viewpoint and do glycol dinitrate can be attained by less than 8 percent not possess the disadvantages above referred to. of nitrocellulose in the explosive oil. Usually, only 3-5 The better physiological acceptability of propylene percent is required to attain this result. glycol dinitrate may be explained by the fact that the sub 60 As gelatinizing aids may generally be mentioned hy stance has relatively little solubility in the blood of man. drogen bond-forming substances. Such aids will be ef The solubility of the propylene-glycol dinitrates in water, fective in proportion to their ability to form such bonds. as compared with nitroglycerine and nitroglycol (the di As examples of such substances there may be mentioned: nitrate of ethylene glycol), is evident from the following Alcohols.-Aliphatic monohydric primary, secondary table. The values set forth relate to the solubility at 65 and tertiary alcohols, containing from 1 to 10 carbon 20° C. atoms, for example methanol, ethanol, isopropylalcohol, Percent n-propylalcohol, the butyl alcohols, the amyl alcohols, Nitroglycerine ------------------------------- 0.18 n-decanol and nonyl carbinol, aliphatic polyhydric al Nitroglycol --------------------------------- 0.63 cohols such as ethylene-glycol, diethylene-glycol, the 1,3-propylene-glycol dinitrate ------------------ 0.24 70 propylene-glycols and glycerol; 1,2-propylene-glycol dinitrate ------------------- 0.13 Ketones.-Aliphatic ketones such as acetone, methyl 3,208,890 3. 4. ethyl-ketone, methylisobutyl-ketone and up to the deca those skilled in the art without changing the essential nones as well as the bicyclic ketone camphor; characteristics and the basic concept of the invention. Esters.-Esters of aliphatic alcohols with formic acid, Example I acetic acid, and propionic acid, for example ethyl acetate and butyl acetate, polyhydric alcohols partially esterified A plastic explosive was made up by mixing together With acetic acid or nitric acid such as the partial esters the following ingredients: of ethylene-glycol, diethylene-glycol, the propylene 9. glycols and glycerol with acetic aaid and nitric acid, such 1,2-propylene-glycol dinitrate ---------------- 37.0 as mononitroglycerine, mononitroglycol and dinitro Nitrocellulose ------------------------------ 1.3 glycerine; O Methanol --------------------------------- 0.4 Ethers-With lower alkyls monosubstituted ethylene Ammonium nitrate -------------------------- 41.5 glycol and diethylene-glycol in which the lower alkyls Sodium nitrate ----------------------------- 18.75 may be methyl, ethyl, propyl and butyl, such as glycol Wood flour -------------------------------- 1.0 monomethylether and glycol-monoethylether. Chalk ------------------------------------ 0.05 Other gelatinizing aids are mono- and di-nitrosubsti The oxygen-balance of the explosive was -4.0%. tuted derivatives of benzene and toluene. If an ex The properties of the explosive were as following: plosive oil, containing propylene-glycol dinitrate, is free from nitroglycerine, the latter substance may be added as Volume weight -------------------------- 1.53 a gelatinizing aid up to amounts of 8 percent, for ex Gap test (24 mm. cartridge), mm. at 20° C. -- 120-130 20 Impact sensitivity test according to Kast, 2 kg. ample. fall weight, percent detonation per cm. fall THE OXYGEN-DELIVERING INORGANIC SALT height -------------------------------- 0/60 As examples of suitable oxygen-delivering inorganic The mixture was prepared by first mixing together salt may especially be mentioned nitrates and/or per the propylene-glycol dinitrate and the nitrocellulose, chlorates of ammonium, alkali-metals and alkaline whereupon the methanol was added to the mixture ob earth metals, such as sodium nitrate, potassium nitrate, tained. Gelatinizing took place satisfactorily