US1627861A - Propellant powder and process for making same - Google Patents

Description

Patent ay 10, 127.

Amazon. s. ONEIL, or Essa." Amen, ILLINOIS, ASSIGNOB. T WESTERN CARTRIDGE 'coaaremr, or EAST ALTON, ILLINOIS,'A CORPORATION or DELAWAR PEOPELLANT POWDER AND PROCESS FOR MAKING SAME.

- No Drawing.

This invention relates to propellant powders, and more particularly to nitro-cellu-- lose powders adapted for use in and suitable for cylinder guns and small arms.

Smokeless powder having a nitrocellulose base, adapted for rifle fire arms and more particularly for use .as military ammunition,

The nitrocellulose is then dehydrated by displacing the water with alcohol in a. dehydrating press. The dehydrated product has then added thereto ethyl-ether together with a stabilizer, such as diphenylamin, and the whole mixed or incorporated so as to form a colloid. This colloid is then formed smoke, while both have a corrosive action into blocks, pressed through dies to form strings and the strings :can be cut to form the grains. The grains'are then placed in a solvent recovering apparatus to recover the solvent and are then dried. i

The above process forms a dense nitrocellulose colloid which burns progressively, that is, in layers until completely consumed. While it is, therefore, peculiarly adapted for rifle arms where the projectile seals the bore, it is not suitable for cylinder uns and small arms. In powders for cylinder guns, it is necessar that the initial burning be at a more rapit rate, due to the fact thatthe bore of the gun is not sealed by the projectile. Accordingly if the pressure is not rapidly developed, incomplete burning results, since the rapidity ofburning de ends directly upon pressure. According y, where a dense nitrocellulose powder is employed in a cylinder gun, the result will be unburnt powder and escape of the gases around the wads, thereby reducing the ballistic efliciency. I A

In the preparation of nitrocellulose powder for use as military ammunition, it has Application filed February 10, 1923. Serial No. 618,888@

further been the practice to ubject the dense nitrocellulose colloid to surface treatment by coating or impregnating the same with a suitable .nitro-hydrocarbon, thereby producing'a so-called progressive powder having. a. still lower initial pressure without, however, lowering the velocity of the projectile. The function of the solvent, however, is to act as a deterrent, as this solvent is'not only less explosive and less readily ignitable' than the dense nitrocellulose colloid, but it acts as a seal; it will, therefore, be seen that this surface treatment goes still I further inthe opposite direction than the requirements and characteristics desiredin a-powder suitable'for use incylinder guns and small arms.

In order to produce a smokeless powder having a nitrocellulose base, ithas been the practice heretoforeto either mix with the ;nitrocellulose, metallic nitrates or a more 'violent explosive ingredient, such as nitroglycerin. The. former, however, produces on the'bore of the gun. It has also been the practice to employ weak solvents so as to only partially gelatinize the nitrocellulose, or to employ ingredients with thenitro-'- cellulose while in-a plastic state which are subsequently extracted. These, however, are open to the objection that they do not provide stable and uniformly burning grains It has also been proposed to incorporate with smokeless powder, either by mixing therewith or as a supplementary priming charge,

black powder or to cause the black powder to adhere to the nitrocellulose powder grains by a binder. These, however, are not only open to the objection that they introduce smoke forming and corrosive constituents,

but the black powder'is liable'to segregate during shipment, thereby causing 'a given charge to beununifornl.

' One of the objects of this invention, therefore, is to provide a propellant owder and more particularly one having a ense nitrocellulose colloid as a base, together with a process of making the same, whereby the surface of the powder grain is so modified that itwill approach the rate of burning of the so-called bulk powders, and in order that this rate of burnng may he so accelerated that the initial pressure is developed at the rate required to enable its utilization and render it suitable for cylinder guns and small arms.

There are at the present time large quantities of military ammunition, both surface treated and untreated, which have no present use. It isnot economical to keep such powder in storage, especially since it deteriorates and it is entirely unsuitable for peace and economic purposes.

Another object of this invention, therefore, is to provide a process adapted for the treatment of military smokeless powders so as to permit their utilization in and render them suitable-for cylinder guns and small arms, and to so modify such military powder" that the rate of burning is accelerated in order that the pressure may be developed more readily. The process is not, however, restricted to the treatment of dense military powders which have been salvaged, but it is adapted to the treatment of freshly prepared dense nitrocellulose powders.

Further objects will appear from the detail description in which are given a number of examples illustrating embodiments of this invention.

In accordance with this invention. the powder grain is modified so as to form a dense core surrounded by a less dense and porous envelope. This is accomplished by swelling the .surface of the grain to the desired depth of penetration and the swollen envelope so formed is then fixed. Thisfixing is accomplished in such a manner as to cause not only interruption of the swelling in order to secure an envelope of the desired depth, but also to break up the surface in order to leave an open and porous envelope which is readily ignitable.

Generally stated which, upon penetration into the grain,

causes an envelope to be formed which is less dense than the body of the dense colloid,

and the solvent action is continued until the desired depth of penetration and the desired envelope thickness has been obtained. The action is then interrupted in such a manner as to not only limit the penetration, but so as to also produce an envelope which is not. only less dense than the core which it suras a base material a dense colloided nitrocellulose powder, such as standard untreated the dense nitrocellulosecolloidis subjected to the action of a solvent The powder 1s ground or cut up in any suitable apparatus to the state of division desired and it is then screened to the desired size. This powder is then intimately mixed with a solid nitro-hydrocarbon, such as dinitro-toluene, in the proportion of ninetyeight (98)'parts of the powder and two (2) parts of the solvent, although the-proportions may be-varied within limits to suit requirements. The mixture is then introduced into a tank provided with a stirring mechanism, or into a tumbling barrel, which .tank or barrel has been previously filled with water and raised to a temperature of to 100 (1, depending upon the nature of the solvent used. The temperature is maintained (by supplying live steam or water to a jacket or by thedirect action of steam) for a suitable period, in case where dinitrotoleune is used for a period of about two hours, while the powder and the solid solvent are rumbledtogether in the water. The solvent under the influence of heat melts and distributes itself uniformly .over the grain. Now dinitro-toluene (as well as other solid nitro-hydrocarbon solvents) under the influence of heat is a solvent and a colloiding agent for nitrocellulose.

Accordingly the solvent penetrates the powder grain, the depth of penetration depending upon the period of heating, the quantity of the solvent, andthe temperature of the heat applying vehicle. It is essential that the penetration takes place rather rapidly, otherwise little or no swelling of the grain takes'plaee. It is also essential" that the temperature be maintained until the desired penetration takes place.

swelling action has progressed as far as de-' sired, cold water is admitted to the mixture in order to rather suddenly chill the contents of thetank or barrel. This causes the dinitro-toluene to chill, thereby partially recrystallizing and losing its solvent properties so that the solvent action is interrupted. At

, the same time, a portion.of the nitrocellulose is partially precipitated from. the colloid, while the dinitro-toluene is also partially precipltated. Accordingly the envelope,

which before the chilling consisted of nitrocellulose colloided with dinitro-toluene, will become partially decolloided. The chilling dense colloid core while the envelope is less I dense than the core and porous. The porous formation of the surface not only causes the powder grain to ignite more readily but the particles of precipitated nitrocellulose are more readily ignitable than 'was the original dense colloid. The structure of the envelope is, therefore, such that it is not only readily ignitable, but it will continue to burn at a higher rate under a reduced pressure, so that if the burning of the envelope supplies the necessary temperature and pressure to afford complete combustion of the balance of the grain. This rate of combustion canbe regulated by variation ofthe thickness of the envelope, which can readily be controlled by extending the penetration period of the solvent.

It will, of course, be understood that after chilling the treated grains are removed from the water and dried in the usual manner.v

This drying will not, however, cause contraction of the envelope to the original-colloid density, but this envelo willremain in a porous condition since t e drying will rather. enhance than detract from the porosity. The drying can be accomplished in any suitable manner asusual in the art.

If a coatedpowder is desired, additional dinitro-toluene may be added after chilling, the water reheated until the solvent is melted and distributed over the surface and chilling P again proceeded with. v

While in the above described embodiment of the process dinitro-toluene has been described as a solvent, it is understood that other solid solvents may be used, such as dinitro-benzene, nitro-naphthalene or othersolid ntro-hydrocarbons. The procedure when using such solvents is similar to that described above. V

It is also ossible to obtain improved results by emp oying diluted volatile solvents, such as acetone, ketones, wood alcohol, etc.

When using volatile solvents, however, the

dense powder is subjected to the actionpf the volatile solvents, either in waterprin the presence of another liquid which Is indiffercut to nitro-cellulose. The action ofthis solvent causes the grains to swell and; in-

crease in volume, and the treatment is continued until the desired penetration has been effected. The treated grains are then quickly immersed in hot water which causes violent expulsion of the solvent; thegrams so treated may then be chilled by dropping is not necessarily limited thereto.

them in cold water. The grains may then be dried 'in any suitable manner.

' It will thus be seen that the invention accomplishes its objects. A powder is obtained which comprises a core of a dense nitrocellulose colloid which is enveloped by a less dense and porous envelope, which envelope being further decolloided, and arts of the broken and porous surface containing uncolloided nitrocellulose which is readily ignitable, and an uncolloided combustible solvent. The result, therefore, is a powder grain whose surface is readily ignitable, so that its combustion is not only started at low pressure, but the envelope supplies and so maintains the necessary heat and pressure to secure and maintain the requirements for complete combustion of the dense core.

'Moreover the character and formation of grains. It will further be noted that the desired result is obtained without the mixture of smoke formin or corroding. ingredients, since the'resulta 1'. grain is itself modified by modifying the density, porosity and chariictgr of the surface of the nitrocellulose col- While in the specification and claims the term grain is used, it is to be understood that it is intended as a Word of eneral description and not of limitation, ut to include the various forms in which powder is roduced for use. It will be further understood that while theories of formation and operation have been advanced, the invention It will further be obvious that various changes maybe made in details without departing from the spirit of this invention; it is, therefore, to be understood that this invention is not to be limited to the specific details described.

Having thus described the invention, what is claimed is:

. 1. A propellant powder grain comprising, a dense core surrounded by a porous envelope.

2. A propellant powder grain comprising, a dense colloid, the surface of which is porous.

3. A propellant powder grain comprising, a dense colloid, the surface of which is partially decolloided.

4. A propellant powder grain comprising, a dense colloid, the surface of which is colloided. with a solvent so as to provide an envelope which is less dense than the core.

5. A propellant powder grain comprising,

Int)

a dense colloid, the surface of which is colloided with a solvent so as to provide a porous envelo e.

6. A propell a dense colloid, the surface of .which is partially decolloided and contains a combustiwith a solvent and is less dense than'thecore.

12. A powder gram of dense colloided nitrocellulose, the surface of which is porous so as to be readily ignitable.

13. A powder grain of dense colloided nitrocellulose, the surface of which is colloided with a solvent and chilled. v

14. A powder grain of dense colloided nitrocellulose having a chilled colloided surface.

15. A powder grain 'of dense colloided nitrocellulose, the surface of which contains a precipitated nitro-hydrocarbon.-

16. A powder grain of dense colloided nitrocellulose, the surface of which contains precipitated nitrocellulose.

I 17. A powder grain of dense colloided nitrocellulose, the surface of which contains precipitated nitrocellulose and a nitro-hydrocarbon solvent.

. 18. In the art of making propellant powder, the rocess comprising, swelling the surface of t e grain and fixing the envelope so formed.

19. In the art of making propellant powder, the process comprising, swelling the surface. of the grain and chilling the envelope so formed. y

20. In the art of making propellant powder, the process comprising, subjecting the grain to the action of a solvent for the grain material and -precipitating the solvent.

21. In -the-art of'making propellant powder, the process comprising, subjecting the surface of the grain to the action of a solvent for the grain material and expelling the solvent.

22. In the art of making propellant powder, the process comprising, heating a grain, the surface of which contains a solvent and chilling the grain.

23. In the art of making propellant powder, the process comprising, swelling the surant powder grain comprising,

face of a dense nitrocellulose colloid and fixing the envelope so formed.

24. Inthe art of making propellant powder, the process comprising, swelling the surface of a dense nitrocellulose colloid .and' chilling. the envelope so formed. r 25. In. the art of making propellant powder, the rocess comprising, partially decolloiding tlie surface of a dense nitrocellulose colloid.

26. In the art of making propellant powder, the process comprising, subjecting a dense nitrocellulose colloid to the action of a swelling medium and interrupting the swelling so as to fix the envelope so formed.

27. In the art of making'propellant powder, the process comprising, subjecting a dense nitrocellulose colloid to the action of a solvent and interrupting the solvent action so as to fix the envelope so formed.

28. In the art of making propellant powder, the process comprising, subjecting a dense nitrocellulose colloid to the action of a swelling medium and expelling the medium from the envelope so formed.

29. In the art of making propellant powder, the process comprising, treatin a dense nitrocellulose colloid with a solvent or nitrocellulose and precipitating the solvent.

30. In the art of making propellant powder, the process comprising, colloiding the surface of a dense nitrocellulose colloid with a solvent for nitro-cellulose and fixing the envelope so formed.

31. ,In the art of making propellant powder, the process comprising, colloiding the surface of a dense nitrocellulosecolloid with a solvent and partially decolloiding the envelope so formed.

32. In the art of making propellant powder, the process com rising, heating a dense nitrocellulose colloi in the presence of a solvent and chilling the envelope so formed.

33. In the art ofmaking propellant powder, the process comprising, heating a dense nitrocellulose colloid in the presence of a nitro-hydrocarbon solvent and chilling the envelope so formed.

34. In the art of making propellant powder, the process comprising, heating a dense nitrocellulose colloid in the presence of a solvent and a vehicle and chilling the enve lope so formed.

35. In the art of making propellant powder, the process comprising, heating a dense nitrocellulose colloid in the presence of a nitro-hydrocarbon in water and chilling the envelope so formed.

36. In the art of making propellant powder, the process comprising, treating a dense nitrocellulose colloid with a nitro-hydrocarbon first in hot water and then in cold water.

37. In the art ofmaking propellant powder, the process comprising, treating a dense nitrocellulose colloid with a solid nitrohydrocarbon first in hot water and then in der, the process comprising, rumbling a dense cold water. nitrocellulose colloid with a solid solvent in 38. In the art of making propellant powhot water and then'treating the resulting l0 der, theprocess comprising, rumbling a dense colloid with cold water. 5 nitrocellulose colloid 'with a solid solvent in In testimony whereof I affix my signature hot water. this 31st day of J anuary, 1923.

39. In the art of making propellant pow- ARTHUR S. ONEIL'