US1808613A - Propellant explosive - Google Patents

Description

Patented June 2, 1931 WALTER. O. SNELLING, OI ALLENTO WN,

PENNSYLVANIA, ASSIGNOIB. TO TROJAN POWDER. COMPANY, OF NEW YORK, N. Y A CORPORATION OF NEW YORK PBOPELLANI. EXPLOSIVE Il'o Drawing.

My invention relates to propellant explosives, of the smokeless powder type, and its object is to produce an improved smokeless and flashless pro ellant containing nitrostarch. This app ication is a continuation in part of my application Serial No. 47 9,097 for improvements in propellant explosives filed June 20, 1921.

Efforts have heretofore been made to prepare smokeless powder from nitrostarch by colloidization, the nitrostarch being dissolved in a suitable solvent to form a colloid mass, and this colloid mass being then admixed with suitable inorganic oxidizin agents, such as nitrate of soda, nitrate o ammonia, and the like. I have discovered that valuable smokeless powders may be made from nitrostarch, desensitized sufiicientl to be non-detonating, but preserving the s1ze and shape of the original starch granules. I have found further that in employing nitrostarch in the form of' individual grains, I may successfully employ in connection therewith a compound which at the moment of burning will reduce the flame temperature, rendering the explosive substantially flashless. I have found also that.

certain organic or inorganic nitrates, partic ularl guanidine nitrate, when present in sufiicient amounts are satisfactory temperature-reducing agents.

As an illustration of one method of preparing an explosive embodying my invention, I instance the following procedure:

To parts of nitrated starch in the form of the separate nitrated grains of a vegetable starch, I add 37 parts of guanidine nitrate in the form of a fine crystal meal or of fine particles obtained by grinding, and thoroughly mix. I then bring about surface colloidization of the nitrostarch granules in the manner set forth in U. S. Letters Patent No. 1,310,969, issued to me, as as signer, July 22, 1919, employing as the colloiding agent, say, 37- parts of commercial liquid trinitrotoluene. By this procedure, I obtain an intimate mixture of the desensitized nitrostarch 'ranules in their original physical form, a mixed with the temperature-reducing agent, which product I Application filed February 19, 1926. Serial No. 89,418.

can then press in molds to secure grains of the sizes and shapes used in the reparation of ordinary smokeless powder. hese grains may at first be somewhat friable, but after standing for some hours, the grains ain in strength and become quite tough. I desired, this period of aging may be materially shortened by a special hardening treatment, the grains being exposed to a temperature of or higher, for from thirty minutes to an hour.

I have also employed as a colloidin agent a mixture of liquid trinitrotoluene an nitroglycerin. In this instance, I proceed as described in the foregoing paragraph and prefer to use the ingredients in the following proportions: 60 parts of nitrostarch 20 parts of guanidine nitrate, 10 parts of liquid trinitrotoluene, and 10 parts of nitroglycerin.

Instead of desensitizing the nitrostarch granules by surface colloidization, I may employ oil or wax as a desensitizing agent. For example, I may take 15 parts of nitrated starch and mix with this 2 parts of molten paraflin wax, thereafter thoroughly incorporating the desensitized nitrostarch so produced with 83 parts of a suitable temperature-reducing agent, such as 'guanidine nitrate. As the wax has agglomerating as .Well as desensitizing properties, the product may be pressed into grains or particles of any desired size or shapes. In this case, as in that previously given, the nitrostarch granules are sufliciently desensitized to be rendered non-detonating, and the result is a highly satisfactory smokeless and flashless propellant explosive.

Instead of paraffin wax as the desensitizing agent, I may desensitize the nitrostarch with a suitable oil, such, for example, as a mineral oil, and add an agglutinant, such as shellac or coumarone resin,-in suflicient quantity to bind together the granules of starch and the particles of the nitrate to form a coherent mass and permit moldi 'g into grains. Suflicient oil is used to render the nitrostarch non-detonating. For example, I have obtained satisfactory results by using an'amount of oil equal to] 10% of the weight of the ,nitrostarch used, but I do stearic acid, Japan wax, or other equivalent not wish to be limited to this proportion, material,- Vegetable, animal or mineral oil as the proportions are capable o variation or oily, materials may be employed as the So also with agglutinant, various propordesensitizing agent. The colloiding agent, tions may be used. \Vith coumarone resin, I where used, may be other organic nitrates have successfully employed an amount thereor organic nitro bodies than the trinitrotolof equal to by weight of the finished uene and nitroglycerin mentioned, such for duct, example as dinitrotoluene, nitrobenzene, and

In em loying nitrostarch desensitized by mononitronaphthalene. Amylacetate, acemeans of oil, it is not absolutely essential tone or the like, may also be used. It will that a special agglutinant be'employed. For also be understood that I ma use anyecusexample, using 12 parts oil-desensitized nitomary stabilizing agent, suc as dip nyltrostarch and 88 parts guanidine nitrate, the amine, urea or urethane. latter in redient being in slightly moist con- The compacting of my product into grains dition, t e mixture can be compressed at a may be brought about either through the high pressure to form dense grains, and action of pressure alone (as in the manufacserve as an embodiment of my invention. ture of ordinary black powder) or through The proportions of the ingredients may the agglutinating effect of superficial colbe varied within wide limits, particularly loidization, as described in my Patent No. with reference to the relative percentages 1,310,969, heretofore referred to, or through of nitrostarch and guanidine nitrate. The the addition of a specific agglutinant as nitrostarch should preferably constitute hereinbefore described. In any case, the from 10% to of the finished powder, nitrostarch granules are rendered non-detbut for some purposes it is conceiva le that onating, are preserved in their original satisfactory results may be obtained outside form, and are employed with a suitable of this range. I prefer to use from 50% to oxidizing agent to obtain the smokeless and 90% of guanidine nitrate, but in some flashless propellant as described. instances less could be used. The examples I claim: heretofore given indicate preferred percent- 1. A propellant explosive comprising ages of colloiding desensitizing' and agnitrostarch, desensitized by surface colloidiglutinizing agents, but these also may be zation, and guanidine nitrate. varied in amount, the quantities required in 2. A smokeless and flashless powder comany particular case being sufficiently indi- ,prising desensitized nitrostarch and a temcated to the explosives chemist by the purperature-reducing agent, the latter being an poses pointed out above. addition product of an amine and nitric For the specific ingredients hereinabove acid. specified, equivalents may be substituted. 3. A smokeless and fiashlesspowder com- As the temperature-reducing agent, instead prising desensitized nitrostarch and an orof guanidine nitrate, I may employ other ganic temperature-reducing agent, the latter nitrates, organic or inorganic, such, for being an addition product of an amine and example, as urea nitrate or ammonium ninitric acid. trate. The structural formulae of these ni- 4. A smokeless and flashless powder comtrates are: prising desensitized nitrostarch and a re- Guanidine nitrate NH: C(NH .HNO action product of guanidine and nitric acid.

Urea nitrate O: C(NH .HNO3 Ammonium nitrate NH .HNO Thus, it will be seen that these compounds may be considered to be addition products 5. A smokeless and flashless powder comprising'desensitized nitrostarch and guanidine nitrate.

' 6. The process of rendering nitrostarch of ammonia or an amine and nitric acid. smokeless and flashless, which comprises For the purposes of the claims, these comthoroughly mixing nitrostarch with guanipounds and their equivalents will be defined dine nitrate in the form of fine particles, as addition products of an amine and nitric and thereafter adding a desensitizing agacid, within which phrase the addition prodglutinant and compressing the mixture into net of ammonia and nitric acid (ammonium grains of the desired form. nitrate) is included. Nitroguanidine is also 7, The process of rendering nitrostarch applicable as a temperature-reducing g n smokeless and flashless, which comprises 1 formula is 2- 2, and thoroughly mixing nitrostarch granules therefore both nitrogllanidine an .gllaniwith guanidine nitrate, and thereafter dine nitrate will be defined in the l im flbringing about surface colloidization of the reaction products of guanidine and nitric nitrostarch granules and compressing the i.

acid. Hydrocellulose may e be used mass into grains of the desired form. place of the other temperature-reducing 8. A smokeless and flashless powder comcompounds with satisfactory results. prising desensitized nitrostarch and a tem- As agglutinants, I may use Waxy mateperature-reduci'ng agent selected from the rials, such as those heretofore indicated, or following group,-guanidine nitrate, am- 1.-

anonium nitrate, urea nitrate, nitroguanime. I

,9. The process of rendering nitrostarch smokeless and fias hless, which comprises thoroughly mixing nitrostarch with a material selected from the following group,- guanidine nitrate, ammonium nitrate, urea nitrate, nitroguanidine,-and thereafter adding a desensitizing agglutinant and compressing the mixture into grains of the desired form.

10. The process of rendering nitrostarch smokeless and flashless, which comprises sired form.

thoroughly mixing nitrostarch granules with a material selected from the following group,-guanidine nitrate, ammonium n1- trate, urea nitrate, nitroguanidine,and

thereafter bringing about surface colloid-' ization of the nitrostareh granules and compressing the mass into grains of the de- WALTER O. SNELLING.-