Патент USA US2405104код для вставки
July 3%, 19416. ~ W; E_ ‘MYDANS _ 2,405,104 ORDNANCE POWDER BAG ' Filed Aug. 7, 1941 " /1 IN VEN TOR. W; “Ram Mydahfi Patented July 30, 1946 2,405,104 ‘UNl’TED STATES PATENT OFFICE 2,405,104 ORDNANCE POWDER BAG William E. Mydans, Cambridge, Mass. Application August 7, 1941, Serial No. 405,879 1 Claim. (Cl. 102-97) (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) 1 2 The invention described herein may be manu factured and used by or for the Government for in contact with pyrocellulose and other mixed governmental purposes, without the payment to me of any royalty thereon. This invention relates to ordnance powder bags 5. The containers or bags should have mechan ical strengthadequate to retain the powder and to permit‘the reasonably rough handling that may be required under the pressure of battle. 6. The powder bag material should introduce or containers. In large caliber guns it is customary to load a projectile into a, gun through an opened breach, propellents. no new defects or hazards such as the holding then to insert propellent powder in an amount to of static electric charges or the release of acrid give the desired range. Finally, the detonator is 10 or toxic vapors which might affect men within a gun turret housing. inserted and the breach closed. The propellent powder, which is usually a pyrocellulose or mixed In addition to the foregoing properties, these pyrocellulose-nitroglycerine composition formed materials should also possess the following ad into grains varying in size with the gun caliber vantages which, however, are not prerequisites for and containing perforations to control the rate 15 a satisfactory and acceptable powder bag. or" burning, is contained in a sack or bag. One 7. The materials should have properties which important and necessary characteristic of the are well-known. These materials should be able material from which these bags is made is that to be readily worked or prepared on equipment ‘following the explosion, whatever residue re which has already‘ been developed and is readily mains must cease immediately to burn, glow, or 20 available. smoulder and so make possible the immediate in 8. The materials should be light in weight and troduction of the next charge with safety. This so add little to transport di?iculties. They should property is lacking in all ?bers of vegetable origin. be low in bulk and so require no changes in the For many years, powder bags for large caliber volume or design of the present gun barrels. ordnance have been made from a natural silk 25 9. The containers made from these materials cloth. Silk has the desired property of no “after should be waterproof and watertight, thus per glow” but is expensive-and is obtainable only from mitting the use of component parts of the pro foreign sources. pellent charge which are sensitive to water. An object of this invention is to devise ord The above and other features of my invention nance powder bags or containers made chie?y 30 may be best understood from the following de from other than naturally occurring animal or scription of exempli?cations thereof, reference vegetable ?bers. being had to the accompanying drawing wherein Another object is to devise such powder‘ba‘gs the single ?gure represents a cross-section from materials which, in addition to the attri through a powder bag incorporating my inven butes of silk, possess the advantages of being inex tion. pensive, readily available, and highly stable dur I may construct my novel powder bags of a. ing long periods of storage. ntirocellulose composition. Such a material pos In accordance with my invention, it is desir sesses in great measure all of the advantages out able to construct ordnance powder‘ bags from lined above. Since the major component of the synthetic organic ‘materials which have the fol 40 propellent charge is nitrocellulose (usually pyro lowing desirable properties: cellulose of between 12 and 13.4% nitrogen) a 1. These materials should burn or be consumed nitrocellulose bag introduces a material not dis during the explosion of thepropellent powder and if any residue remains at the termination of similar to the propellent charge. However, for the powder bags, I prefer to use a nitrocellulose of such explosion, said residue should immediately ' 45 somewhat lower nitrogen content than pyrocellu cease to burn, glow or‘ smoulder. lose, such as a plastic or coating grade of nitro 2. These materials should burn with the least cellulose, i. e., of about 10 to 12% nitrogen. possible residue, thus minimizing gun fouling; The nitrocellulose may be employed in the and further, any residue which remains should formation of powder bags in a number of ways. neither contain nor generate substances corro 50 For example, nitrocellulose may'?rst be dissolved sive to the gun barrel. in suitable solvents. 'Such solvents, which may 3. The materials should be readily available from domestic sources and be low in cost. be employed singly or in various combinations, include the following types: Alcohols, aldehydes, ketones, chlorinated hydrocarbons, ethers, esters, 4. The materials should be stable when sub jected to moisture, light, and ‘storage even when 55 nltropara?ins, ‘hydroxyaldehycles, hydroxyke 2,405,104. 4 3 tones, and the like. Aliphatic, aromatic and alicyclic hydrocarbons may be employed as dil uen s. The speci?c solvents or combination of solvents chosen will depend on a number of fac tors which include the boiling or evaporation ranges desired, the degree if nitration of the nitro cellulose employed, the viscosity characteristics desired in the solution to be cast or coated, the solubility characteristics of the plasticizers, res shown at 4, the material may be stitched prefer ably with silk thread or may be cemented with the cementing compositions already described. Instead of using two layers of nitrocellulose ?lm, one or both of said layers may be replaced by a ?lm of other suitable material such as ethyl ‘cellulose; cellulose acetate, 0 ein or other pro > tein-p-lastic ?lm in order to secure lower in?am mability in handling and transportation, reduced inous materials, cellulose ethers, and the like, l0 tendency toward accumulation of static electric charges or other modi?ed physical properties. which may be incorporated, the ?ammability of Since the physical properties thus enumerated are the solvent mixture, the ease of solvent recovery, usually desirable for the external surface of the resistance to ?lm blushing, etc. bag, preferably such material will be substituted The nitrocellulose solution thus prepared may be cast in the form of a ?lm or may be used to coat a fabric backer as will be described below. for the nitrocellulose layer 2 as shown in the drawing. One method of producing the laminated struc ies may be incorporated in the solution before the , V ture as shown in the drawing is to pass the light weight textile materials enumerated above in a ?lm is castso as to impart to the ?lm the desired degree of flexibility and strength. '20 continuous web under, a spray of or through the nitrocellulose plasticized lacquer solutions to pro Among the plasticizers that may be used, singly duce thereon a continuous ?lm. In order to se or in various combinations to give plasticity or cure sufficient thickness multiple coats may be suppleness to the ?lm are the following types; As already stated plasticizers and resinous bod camphor, triaryl and trialkyl phosphates, phthal ate esters, aryl and alkyl sulfonamides, butyl phthalyl-butyl-glycollate and related materials, castor oil, blown and heat-bodies vegetable oils, methyl abietate, tartaric acid esters, citric acid , esters, lactic acid esters, and the like. Where a minimum of ash and corrosive products are de sired, it is preferable to avoid the use of plasticiz ers containing inorganic constituents, such as tri cresyl phosphate and chlorinated diphenyls. Among the resinous materials that may be em ployed, singly or in various combinations to add body, stiffness, stability, or other modifying prop erty to the ?lm are: Alkyd resins, preferably in the “B” or soluble stage, rosin, rosin esters, tolu ene sulfonamide-formaldehyde resins, furfural ketone resins, dammar, terpene resins, urea formaldehyde resin solutions in butanol, mela required with drying of the ?lm with each appli 25 cation. If desired the ?nal coating may be of some other film forming material such as ethyl cellu lose, cellulose acetate, isobutene polymer, casein, zein, etc., in order to secure modi?cation of the 30 physical properties, especially as it relates to ?ammability during handling and transportation and reduced tendency toward the accumulation of static electrical charges. The use of low viscosity nitrocellulose in the above process will permit the building up of coat ings of appreciable thickness with a minimum number of applications. Comparatively thick sheets of nitrocellulose ?lms may be applied to the fabric web from aqueous emulsions by dipping or under a doctor knife with the advantages of re duced solvents, elimination of solvent recovery systems, lowered ?re hazard and ease of applica tion. Nitrocellulose ?lm, especially in the thicker rials having a nitrogen content range of 10 to 45 gauges, may be deep-drawn by the application of heat and pressure to make seamless containers of 12%. The viscosity properties may likewise be high mechanical strength and water resistance selected to secure a coating or casting solution of with low weight and bulk. Such a container, the desired properties. Where proper considera e. g., a cylinderwith bottom integrally formed and tion is given to the plasticizers Or other materials present in the solution, scrap nitrocelullose ?lm or 50 having a diameter to ?t snugly into the gun barrel can be ?lled with the powder charge and the top other waste nitrocellulose products may be em sealed by crimp-?tting or cementing in place a ployed. ' circular disc of the same material. Such a The ?lm may be formed in any suitable man method of processing lends itself readily to mass ‘her, as by casting and drying in the usual way. ’ The ?lm is then formed into bags or sacks by 55 production technique. Instead of making the powder bags of nitrocel stitching, as with silk thread, or by cementing lulose ?lm, the powder bags may be made in fab‘ with resinous or nitrocellulose composition adhe ric form from spun nitrocellulose yarn that has sives or with ‘medium-boiling nitrocellulose sol vents such as the monoethyl ether of diethylene not been denitri?ed, i. e., treated to hydrolyze .o? glycol. ‘ 60 some of the nitrate groups and thus reduce its in?ammability. Such nitrocellulose fabrics can Instead of constructing the powder bag of a easily be made by nitrating puri?ed cotton fabric single thicknessof ?lm as described above, the of the correct weight and weave in batch nitra bag maybe made of laminated material as shown tions or even in continuous process nitration. in the drawing. The inter-layer I may be of Conventional nitrating mixtures of nitric and sul some light weight fabric such as silk “mummy” furic acids are used with carefully controlled tem cloth, which is a silk cheesecloth having a very peratures. Thereafter the nitrated' fabric is low weight of silk per square yard. Likewise this washed, stabilized by boiling in dilute acid'solu~ interlayer may be of wool, cellulose acetate, syn tions, then in water, then in dilute alkaline solu thetic casein or soy bean ?ber cloth, nitrocellulose fabric which may be prepared as described below, 70 tions, and then again in water to remove hemi celluloses, cellulose sulfates and low nitrate esters and such other synthetic fabrics as represented that contribute to instability. The» material is by ‘-‘nylon.” On each side of the interlayerv l is then dried. Y , formed the ?lms 2 and 3 cast, coated or cemented In batch nitrations the foregoing process could on said interlayer. Where the edges of the lami be carried out either on the piece goods or on the nated material forms a seam as, for example, is mine-formaldehyde resins, and the like. The nitrocellulose which is dissolved as de scribed above is preferably selected from mate 2,405,104 5 complete cotton bags after cutting and sewing. Under carefully controlled conditions of nitration, the ‘cotton fabric not only does not lose its me chanical strength but such strength may be in respect. Tests on commercial ethyl cellulose and cast ethyl cellulose ?lm have shown the mate rial to have a very low degree of flammability, and ?lms once lighted have no tendency to con tinue to burn, glow or smoulder when‘ the ignit creased. In this form, nitrocellulose of any de ing flame is removed. Ethyl cellulose ?lm may gree of nitration between 9% and 14% nitrogen may be employed although I prefer to use a collo_ be made in a variety of ?lm-thicknesses, widths and in combination with a variety of plasticizers, dion stage with nitrogen content of about 10% resins and waxes to give ?lms having a wide to 12%. variety of physical characteristics. In addition Were the powder bags to -be made of nitrocel to using ethyl cellulose in a laminated material, lulose yarn, it is desirable to nitrate the cotton the ethyl cellulose ?lm itself may be utilized. cloth or the completed bags as described above Powder bags can be formed from such ?lm by in order to eliminate the necessity of looming so stitching or cementing. Ethyl cellulose is- com inflammable material as nitrocellulose yarn. In‘ the arrangement as shown in the drawing 15 patible with nitrocellulose and may be used in the interlayer i may be made of a light weight combination with nitrocellulose, together with plasticizers and resins if desired, to give ?lms cotton cloth nitrated as described above. Such having modi?ed physical properties, such as the 'nitrated cloth as 'I have described abovec'may be" rate of burning, decreased ?ammability during modi?ed by immersion in solvents, ‘in solvent plasticizer mixtures, in solvent-plasticizer-resin 20 handling and transportation, and increased flex solutions, all with or without the addition of non-solvent diluents, e. g., hydrocarbons. By such treatment over controlled periods of time, partial or extensive swelling or “colloidizing” of the‘ nitrated ?ber may be accomplished, together with absorption by the ?ber of such plasticizers and/or resins that have solvent power or affinity ibility. Other cellulose ethers, such as benzyl cellulose, have similar properties and may be substituted for ethyl cellulose in these applications. Ethyl cellulose is soluble in a wide variety of solvents, particularly in mixed solvents, and is compatible with a wide variety of plasticizers, resins, waxes, raw, blown or heat-bodied oils, for nitrocellulose. Dyes, which, for example may be used to characterize the type of powder to be bituminoussubstances, etc., making possible the contained in the bag, may be incorporated at this 30 formation of ?lm having a wide variety of physi cal properties. stage. On subsequent drying, such treatment Cellulose acetate, mentioned as a component will serve to cement adjoining ?bers together to part of the laminated material from which my give a more impervious and stiffer fabric, though novel powder bags may be made, also has prop the latter may be modi?ed Widely by the choice of plasticizers and/or resins that may be em 35 erties suitable for this purpose. Flame tests on commercial cellulose acetate ?lm have shown that ployed. The solvents, plasticizers and resins al the material burns and also fuses readily, but the ready listed above are suitable for this purpose. films once lighted have no tendency to continue The nitrocellulose of which my novel powder to burn, glow or smoulder when the igniting bags are made may be employed mixed with cellu lose ethers such as ethyl cellulose in order to con 40 ?ame is removed. Cellulose acetate is available in the form of yarn and in a great variety of trol its various physical properties such as rate woven and knitted fabrics, and also in the form of burning, stiffness, melting or softening point. of ?lm in a variety of widths, thicknesses. and The ?nished nitrocellulose bag or container plasticizer-resin compositions having a wide vari may be given a coating of graphite in a thin lacquer or other suitable adhesive or binder in 45 ety of physical properties. In addition to the use of cellulose acetate as one or more of the order to facilitate the ready dissipation of any layers of the laminated structure as shown inthe static electrical charges that may accumulate. drawing, powder bags may be made by knitting The same end may be achieved by coating the cellulose acetate yarn or by cutting and stitching bags with very thin ?lms of hygroscopic or mois ture-retaining material such as gelatin-glycerol 50 suitable cellulose acetate fabrics into the desired shapes. The ?nished fabric container may be water combinations, with or without the incor poration of graphite. coated with ?lms of nitro-cellulose to accelerate burning during the combustion of the charge or “Nylon,” which I have mentioned above, is to make the container more impervious to mois formed by the condensation of aliphatic dicar boxylic acids with aliphatic diamines. It is a 55 ture transfer. The cellulose acetate ?lm, especially in the molecularly oriented, high-molecular weight thicker gauges, may be deep-drawn by the appli polyamid and as such bears a close chemical rela cation of heat and pressure to form seamless con tionship to silk and wool. It melts at a lower tainers of high mechanical strength. Such a con temperature than does silk, but fails to burn when exposed to a free ?ame, even when a thin fabric 60 tainer, e. g., a cylinder with an integrally formed bottom and having a diameter snugly ?tting the of this material is held directly in a ?ame. This gun barrel can be ?lled with the powder charge material, drawn into ?laments suitable for knit ting or spinning, can be formed into powder bags and the top sealed by crimp-?tting or cementing or sacks that will show no after-glow following in place a circular disc of the same material. the combustion of the explosive charge. Alter natively, the material can be extruded through a slit and stretched before cooling to yield a strong, durable, light-weight ?lm that may be formed into powder containers by stitching or cement 65 Such a processing method lends itself readily to mass production technique. Similarly, as detailed above in the application of nitrocellulose and ethyl cellulose to this prob lem, cellulose acetate ?lm can be formed into ing. As already stated, thin “nylon” fabrics may 70 bags by stitching or cementing, or composite ?lm of high mechanical strength can be produced by serve as the interlayer I of the laminated mate rial as shown in the drawing. . laminating two cellulose acetate ?lms to a rein forcing interlayer of suitable fabric. Or, for one Ethyl cellulose, which I have indicated may be of the cellulose acetate ?lms in the composite used as a component part of my novel powder bag, has properties which are desirable in this 75 ?lm, other ?lm materials may be substituted, 2,405,104‘ 7 ers that meet the basic requirements of a satis factory powder bag. These materials may be compounded with suitable plasticizers, resinous e.; g., nitrocellulose ?lm to give accelerated burn ing during the combustion of the charge. , _Fabrics may be coated with cellulose acetate > compositions (cellulose acetate, together with materials, waxes, etc., and cast into ?lms, coated suitable plasticizers and resins if desired, homo Cl on fabrics or upon other ?lm material to yield de sirable products for my purpose. The resulting geneously dispersed in suitable solvents) by spraying or immersing the continuous fabric web ?lms may be hardened or cured by treatment with formaldehyde and may be rendered less sensitive to water and more readily inflammable ,Other cellulose esters and mixed esters have similar properties to cellulose acetate and may be 10 during combustion of the charge by a coating of substituted for the latter in Whole or in part to cellulose-nitrate, wax, resin, or similar materials, secure modi?ed physical properties. These in It is desirable to avoid the use of ?xed alkalis clude cellulose acetobutyrate, and cellulose aceto and the like as solubilizers in preparing the pro propionate. tein solutions, or the use of alums, chromic salts Instead of the synthetic cellulose materials al 15 and the like as hardening or curing agents, as with such solutions. ' ready described, isobutene polymers may be used 7 such a practice will lead to a high ash or residue in the construction of powder bags. in the gun after combustion. Urea and various Isobutene polymers are available in different aliphatic amines make suitable protein solubiliz degrees of polymerization ranging from thick ing agents,v though zein is readily dissolved in syrup-like ?uids to rubber-like materials. These 20 80%’ ethanol. Polyhydric alcohols and amides materials have the unique property of volatiliz make suitable plasticizers and rosin, manilla ing without residue when subjected to tempera copal, and shellac are examples of suitable resins tures of 400-500“ F. and higher. These isobu for use in such compositions to add to the body tene polymers are compatible in general with ma— and modify the ?lm properties. These protein terials having very low contained oxygen per centages, e. g., Waxes in general, including paraf ?n and ozokerite waxes, petrolatum, rubber, as 25 ?lm materials have no tendency toward the ac phalts, pitches, rosin, rosin esters, dammar, ter pene resins, and the like. Isobutene polymers can be compounded with various combinations 30 of the above substances and dissolved in aliphatic, aromatic or alicyclic hydrocarbons, terpenes, chlo rinated hydrocarbons, etc. to yield a material cumulation of static electric charges. The term “coating” as used in the appended claim is intended to include applied pre-formed ?lms as well as coverings applied in liquid or plastic form. i What is claimed is: An ordnance powder bag of the type which when ?lled with a propellent powder charge is adapted for insertion into a gun ‘barrel for use as suitable for coating fabrics such as those listed above as reinforcing-interlayers, to yield suitable 35 the propellant for separate loading ammunition, bag or container material or for coating other said bag having its walls formed of a composite sheet or ?lm material to secure modi?cation of sheet-like material formed of a light weight com the physical properties of the latter. Isobutene bustible fabric on each side of which is a ?lm of polymers, suitable for use according to the inven tion, appear on the market under the trade 40 nitrocellulose adhering thereto and having upon the nitrocellulose ?lm exteriorly ‘of the bag a name “Vistanex.” coating of a combustible material which has less The protein-plastic materials mentioned above ?ammability and less tendency to accumulate as being useful in ?lm form as one of the layers static electricity than nitrocellulose, and having of the laminated structure shown in the drawing are also available in fabrics and in woven and 45 upon the last mentioned coating a coating com knitted fabrics. Such protein-plastic materials have been made from puri?ed casein andysoy proteins and also from zein from corn. The chemical nature of these materials bear a close relationship to that of silk and wool and such ma terials may be made into powder bags or contain— prising a material which is a conductor of elec tricity whereby static electric charges accumulat ing'upon the bag may be allowed to escape from the bag. WILLIAM E. MYDANS.