US1454414A - Progressive nitrocellulose powder containing nitroguanidine - Google Patents

Description

Patented May S, 'lQZ3.

UNHTED @TATES assert areas care.

JOHN M. SKILLING, OF WILMINLGTON, DELAWARE, ASSIGNOR TO E. I. no JPONT DE NMOURS -& COMPANY, OF WILMINGTON, DEAWARE, A CORPORATION OF DELAWARE.

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This invention relates to progressive nitrocellulose powders containing a substantial proportion of nitroguanidine, and to a process of making such powders.

The object of my invention is to surfaceimpregnate with deterrent materials the surface of smokeless powder grains made from a composition in which a substantial proportion of the nitrocellulose is replaced by nitroguanidine. The substitution of nitroguanidine for a portion of the nitrocellulose gives a powder with lower temperature of combustion and consequently a powder which produces less erosion. This improvement alone constitutes a very substantial improvement over existing powders made of nitrocellulose alone or a mixture of nitrocellulose and nitroglycerine as a base. I

' have found that still further ballistic im- I copending application,

provement is possible by impregnating the surface of the powder grains with deterrent materials having at least some solvent action on the nitrocellulose portion of the powder grains whereby the initial combustion of the powder is retarded and the powder burns more progressively as is characteristic of nitrocellulose powders thus treated.

The powder which I surface impregnate with deterrent materials may be made according to the procedure prescribed in my U. S. Serial No. 535,315, filed February 9, 1922, such a powder containing from 30 to 80% nitrocellulose, and from 70 to 20% nitroguanidine. For example, I may make up a powder composed of parts nitrocellulose, having a nitrogen content in the neighborhood of 13.0% and a solubility in a mixture of 2 parts ethyl ether to 1 part ethyl alcohol in the neighborhood of 40%, and 40 parts finely divided nitroguanidine and 0.5 parts of diphenylamine, as a stabilizing agent, to 100 parts of composition and with or without the addition of nitrohydrocarbons and other ingredients added for various pur oses, such as reducing the hygroscopic qua ities of the composition. I

Application filed June 15, 1922. Serial No. 568,597.

may colloid such a composition, with a, mixture of 2 parts ethyl ether to 1 part ethyl alcohol, and press through a die with an external diameter of .05" provided with centralpin .015" in diameter. The strings of colloid from the above die, I may granulate 1n any convenient length, such as 1/11.

The granulated powder is thenplaced in solvent recovery for several days for the urpose of recovering ether and alcohol. he powderis then dried, preferably at a temperature below C. until the residual alcohol and ether remaining in the powder is.

reduced to the amount desired, generally below 2.0%.

I then take the powder prepared in the abovemanner and surface impregnate it with a deterrent material, such as dinitrot0luene- (1-2-4). As the nitroguanidine component of the powder grain is appreciably soluble in water and the solubility increases with the temperature of the water, I prefer to use a surface impregnating treatment which does not remove a substantial amount of nitro-,

guanidine from the powder. For example, 100 partsof the powder grains to be surface impregnated may be placed in a rotatingpan or bowl. From 3.5 to 5 parts of finely divided 1, 2, 4-dinitrotoluene are then added and the container rotated until the powder grains and dinitrotoluene are thoroughly mixed. A jet of live steam is then directed into the rotating container, gradually .raising the temperature of the mixture of dinitrotoluene and powder until the dinitrotoluene is melted and caused to impregnate the surface of the powder grains because-of its solvent action on the nitrocellulose. Care is taken during this treatmentto prevent excessive cond'ensationof steam, as I desire to prevent as far as possible the extraction of the nitroguanidine component of the powder grain. A small excess of the amount to be incorporated is usually added to the mixing vessel to take care of mechanical losses; thus 4.1 parts may be added when it is intended to have the resulting powder contain 4 parts of deterrent.

The effect of surface impregnating the pow der grains with the dinltrotoluene is illnsamount of dinitrotoluene use of 'dinitrotoluene with a weight of charge of 47.0 grains, an instrumental velocity at 78 feet of 2380 f. s. with a mean pressure of 48,140 pounds per square inch. After surface impregnating the powder grains with approximately 4 parts dinitrotoluene to 100 parts of powder, the impregnated powder, with a weight of charge of 51.0 grains, gave an instrumental velocity at 78 feet of 2459 f. s. with a mean pressure of 46,280 pounds per square inch.

While I have described only one composition, it will be understood by those familiar with the art that the proportions of nitroguanidine and nitrocellulose varied. While I have described simply the and specifically the 1, 2, 4-derivative, it will also be understood that I may use any deterrent material or mixture/of deterrent materials having an appreciable solvent action on the nitrocellulose of (the powder grain under the prevailing conditions. Deterrent materials which aresuitable alone or in admixture are very numerous, but I will name only a few, such as mononitronaphthalene, dinitrotoluene, trinitrotoluene, diethyldiphenylurea, etc.

I claim:

1. As a new propellant, a nitrocellulose powder containing nitroguanidine and having its surfaces impregnated with a deterrent material.

2. As a new propellant, a nitrocellulose powder containing nitroguanidine and having its surfaces impregnated with substantially pure 1, 2, 4-dinitrotoluene.

3. As a new propellant, a nitrocellulose powder containing nitroguanidine and having its surfaces impregnated with 3, nitrohydrocarbon.

4. As a new propellant, a nitrocellulose powder containing nitroguanidine and having its surfaces impregnated with a material having a solvent action on the nitrocellulose component of the powder grain.

can be widely.

vdine, the surfaces of said 5. As a new propellant, a nitrocellulose powder containing nitrocellulose and nitroguanidine'and having its surface impregnated with a deterrent material, each 100 parts of nitrocellulose and nitroguanidine taken together comprising from about 30 to 80 parts of nitrocellulose, and from 70 to 20 parts of nitroguanidine.

' 6. As a new' propellant, a nitrocellulose powder containing nitrocellulose and nitroguanidine and having its surface impregnated with dinitrotoluene, each 100 parts of nitrocellulose and nitroguanidine taken together comprising from about 30 to 80 parts of nitrocellulose, and from 70 to 20 parts of nitroguanidine.

As a new propellant, nitrocellulose powder grains containing about parts of nitrocellulose, about 40 parts of nitrog'uanidine, and a deterrent material atthe surface of said grains. I

8. As a new propellant, nitrocellulose powder grains containing about 60 parts of nitrocellulose, about 40 parts of nitroguanidine, and dinitrotoluene at the surface of said grains.

9. As a new propellant, a nitrocellulose powder containing nitrocellulose of about 13% nitrogen content and nitroguanidine and having its surface impregnated with a deterrent material, each 100 parts of nitrocellulose and nitroguanidine taken together comprising from about 30 to 80 parts of nitrocellulose, troguanidine.

10. As a new propellant, nitrocellulose and from to 20 parts of nipowder grains containing nitrocellulose of about 13 0 nitrogen content and nitroguanigrains being impregnated with a deterrent material having a solvent action on the nitrocellulose component of said grains.

In testimony whereof I afiix my si nature. JOHN M. SKIL ING.