Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F42—AMMUNITION; BLASTING
  • F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
  • F42B5/00—Cartridge ammunition, e.g. separately-loaded propellant charges
  • F42B5/02—Cartridges, i.e. cases with charge and missile
  • F42B5/18—Caseless ammunition; Cartridges having combustible cases
  • F42B5/192—Cartridge cases characterised by the material of the casing wall
• • C—CHEMISTRY; METALLURGY
  • C06—EXPLOSIVES; MATCHES
  • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
  • C06B21/00—Apparatus or methods for working-up explosives, e.g. forming, cutting, drying
  • C06B21/0091—Elimination of undesirable or temporary components of an intermediate or finished product, e.g. making porous or low density products, purifying, stabilising, drying; Deactivating; Reclaiming
• • C—CHEMISTRY; METALLURGY
  • C06—EXPLOSIVES; MATCHES
  • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
  • C06B23/00—Compositions characterised by non-explosive or non-thermic constituents
  • C06B23/001—Fillers, gelling and thickening agents (e.g. fibres), absorbents for nitroglycerine
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F42—AMMUNITION; BLASTING
  • F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
  • F42B5/00—Cartridge ammunition, e.g. separately-loaded propellant charges
  • F42B5/02—Cartridges, i.e. cases with charge and missile
  • F42B5/18—Caseless ammunition; Cartridges having combustible cases
  • F42B5/188—Manufacturing processes therefor
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S102/00—Ammunition and explosives
  • Y10S102/70—Combustilbe cartridge

Definitions

• the base is then treated with a binding agent to facilitate forming.
• a crystalline explosive is added to the dispersion and the item is formed and dried. Prior to the addition of the explosive, it is treated with a cationic charge-inducing agent to facilitate bonding to the fibrous base.
• This invention relates to a combustible cartridge or case for use in munitions and a method of making the same.
• the cartridge or case, prepared in accordance with this invention is for use as a container for the high energy ingredients of a munition such as propellants, igniters, and pyrotechnic compositions.
• Disposable containers for munitions such as cartridges and cases have been prepared in the past. However, these have not possessed all that is desired of such containers in the field. For instance, such containers, cartridges or cases are not completely combustible. Further, lack of strength of such containers leads to many problems in the field as does lack of imperviousness to water and moisture. Also, problems in fabrication and cost have been quite vexing.
• one of the methods of fabricating a combustible cartridge or case is the felting technique.
• the difficulties with the technique include the danger of handling dry nitrocellulose. Also, the ultimate physical properties and combustibility of the case depend on the amount of lacquer utilized and its uniform distribution through the dried case.
• the subject invention answers the needs of the art with special emphasis on a combustible cartridge or case and method of making the same.
• the cartridge or case of this invention which is easily ignitable, possesses improved physical and chemical properties including a controllable burning rate and a more complete degree of combustion.
• the process of this invention is based entirely upon an aqueous system which leads to a more uniform dispersion of binder and a more complete coating of fibers.
• such system is more highly preferable from the standpoint of safety including the elimination of potential fire and health hazards arising from the handling of volatile solvents and dry nitrocellulose.
• An object of the present invention is to provide a combustible cartridge having a fibrous base containing a multitude of voids or interstitial openings wherein are deposited a mass of crystalline explosive and a method of making the same.
• Another object is to provide a process of making a combustible container for munitions having improved physical and chemical properties.
• Another object is to provide a fibrous combustible base containing a crystalline explosive for use in the fabrication of a cartridge or case for munitions.
• the structure of this invention comprises a fibrous base having a multitude of voids or interstitial openings wherein is deposited a mass of crystalline explosive.
• the latter explosive is held in position in the fibrous structure by means of an attraction between differing charges on the fibrous structure and the explosive.
• the process of this invention includes the step of dispersing a fibrous base material in an aqueous solution. Subsequently, an additive is added to disperse and condition the fibrous base for the reception of a crystalline explosive which is hereinafter added to the slurry as will be more fully described below. At this point, a binder is added to the slurry to give structural integrity to the item formed from the slurry. The crystalline explosive mentioned above is now added to the slurry in the desired amount. Prior to the addition of the crystalline explosive, it is treated with an electrolyte to condition it for adherence to the fibers of the item. The fibers are now formed into the desired shape and dried to give a combustible item.
• the chemically degenerated and inherently weak and thermally unstable nitrocellulose of the art is replaced by a high energy, heat resistant and thermally stable crystalline ingredient such as pentaerythritol tetranitrate (PETN), cyclotetramethylene tetranitramine (HMX), cyclotrimethylene trinitramine (RDX), diaminotrinitrobenzene (DATB), and triaminodinitrobenzene (TADB), and 2,4,6-trinitrophenylmethylnitramine (tetryl).
• PETN pentaerythritol tetranitrate
• HMX cyclotetramethylene tetranitramine
• RDX cyclotrimethylene trinitramine
• DATB diaminotrinitrobenzene
• TADB triaminodinitrobenzene
• tetryl 2,4,6-trinitrophenylmethylnitramine
• the fibers possess an improved anionic charge induced thereon by sodium carboxymethylcellulose and the crystalline explosive possesses an improved cationic charge induced thereon by means of an electrolytic solution.
• the charges are attracted to each other and the explosive is bonded to the fibers at the site of deposition.
• any feltable and combustible fibrous material may be utilized in the construction of the combustible cartridge of this invention.
• fibrous material includes cellulose fibers in the form of kraft or spun filaments, and synthetic fibers such as those of the polyamide or polyester type.
• the fibrous material should be dispersed in an amount between about 8 and 50 percent, but optimum results have been achieved when 25 percent of fibrous material is utilized in the process. However, if an amount below about 8 percent is used, the final end item will be inherently weak. Also, it has been found that the combustible cartridge will not possess the properties desired if the end item is composed of more than 50 percent of fibrous material.
• the additive which is used to disperse and condition the fibrous slurry is sodium carboxymethylcellulose.
• This material is added to the slurry in order to coat the fibers and thereby give such fibers a propensity for eventual electrical bonding to the crystalline explosive which is subsequently added in the process.
• Such sodium carboxymethyl cellulose is added to the slurry in an amount between about 2 and 10 percent, but the maximum effect is achieved when it is added in an amount between about 3.5 and 4.4 percent.
• an amount below about 2 percent is added, the fibers in the slurry are not uniformly dispersed throughout the slurry, nor is the slurry of sufiicient anionic character to insure the desired amount of electrical bonding between the crystalline explosive and the fibers in the end item. Further, hardly any improvement is achieved in electrical propensity when an amount above 10 percent is utilized in the process.
• the binder which is utilized to adhere the fibrous mat as a unit on the mold includes polyamides. This includes the reaction product of polyethyleneimine with dibasic acids such as oxalic acid, maleic acid, malonic acid, adipic acid, and sebacic acid. These products should then be subsequently treated with epichlorohydrin prior to use.
• the binder prepared as described should be added in an amount between 2 and percent, however, an excellent degree of structural integrity of the fibrous item is achieved when about 12 percent of the binder is utilized in the process. If less than 2 percent of the binder is used to form the item, the adherence of the fibers to each other will be rather weak and the structural integrity of the item will be greatly deminished. However, if an amount greater than 20 percent is used, the combustible nature of the item will be in jeopardy.
• the crystalline explosive which is used to form the combustible mat includes PETN, HMX, RDX, DATB and TADB and tetryl. Up to 70 percent of the crystalline explosive may be used to form the combustible item but between about 45 and 70 percent is preferred. Below about 45 percent, the cartridge will not combust as well as desired but above 70 percent, the mat is structurally weak and rather dangerous to handle.
• the crystalline explosives listed above should be coated with a water dispersible cationic material such as derivatives of acrylonitride or polyvinyl pyrrolidone.
• a water dispersible cationic material such as derivatives of acrylonitride or polyvinyl pyrrolidone.
• the use of these materials tend toward the establishment of additional bond strength between the cellulose molecule, which is anionic, and the crystalline explosive which is cationic in character.
• the coatings although only utilized in the process in small amounts, is sufiicient to decrease the impact sensitivity of the crystalline explosive and this is accomplished by an improvement of the heat stability of the item.
• These water dispersible cationic materials may be considered as acting as pacifiers by satisfying electrical charges known to exist at the surfaces of these high energy nitrated additives. Such additives should be used in an amount between about 2 and 10 percent by weight based on the weight of the crystalline explosive.
• the pH of the process may be maintained between about 5 and 6 during processing in order to facilitate improved bonding between the fibers, which have been conditioned with an anionic charge by sodium carboxymethylcellulose, and the crystalline explosive, which has been coated with a cationic charge-inducing electrolyte.
• EXAMPLE I (A) 3.6 lbs. of kraft cellulose having a freeness of 20 was dispersed in 22.5 gallons of water contained in a tank equipped with a variable speed stirrer. Sodium carboxymethylcellulose, in the amount of 0.45 lb., was added to the slurry as a 5 percent aqueous solution. Subsequently, 0.45 lb. of a binder resin of the polyamide type in the form of a 10 percent aqueous solution was added to the slurry and the slurry was maintained under agitation for 20 minutes.
• a cartridge of this invention was then formed by dipping a mold under vacuum into the tank. After the felted cartridge was formed on the mold, it was forced free by reverse pressurization. Subsequently, the formed cartridge was then lifted from the tank and dried at F. for 8 hours.
• PETN is to be preferred because the excess oxygen available in this molecule is of assistance in. the combustion of the inert portion of the case.
• Other ingredients such as RDX, HMX, and tetryl are to be preferred in the cartridge or case is intended for use at higher temperature.
• DATB and TADB should be used. The quantities of the above materials may be easily adjusted so as to attain the desired physical properties of the product.
• a crystalline explosive positioned and securely adhered in said voids by electrostatic forces, said crystalline explosive being selected from the group consisting of pentaerythritol tetranitrate, cyclotetramethylene tetuanitramine, cyclotrimethylene trinitramine, diaminotrinitrobenzene, triaminodinitrobenzene and 2,4,6-trinitrophenylmethylnitramine.
• a crystalline explosive positioned and securely adhered in said voids by electrostatic forces, said crystalline explosive selected from the group consisting of pentaerythritol tetranitrate, cyclotetramethylene tet'anitramine, cyclotrimethylene trinitramine, diaminotrinitrobenzene, tri aminodinitrobenzene and 2,4,6-trinitrophenylmethylnitramine, said explosive present in an amount between about one and about seventy percent by weight based on the weight of said container.
• a crystalline explosive positioned and securely adhered in said voids by electrostatic forces, said crystalline explosive selected from the group consisting of pentaerythritol tetranitrate, cyclotetramethylene tetranitramine, cyclotrimethylene trinitramine, diaminotrinitrobenzene, triaminodinitrobenzene and 2,4,6-trinitrophenylmethylnitramine, said explosive present in an amount between about fortyfive to about seventy percent by weight based on the weight of said container.

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• Engineering & Computer Science (AREA)
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• Organic Chemistry (AREA)
• General Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
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• Compositions Of Macromolecular Compounds (AREA)

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Cited By (8)

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Citations (7)

• 1968
  • 1968-03-14 US US712913A patent/US3504630A/en not_active Expired - Lifetime
• 1969
  • 1969-02-18 BE BE728570A patent/BE728570A/xx not_active IP Right Cessation
  • 1969-02-21 CH CH265769A patent/CH501205A/fr not_active IP Right Cessation
  • 1969-02-24 IL IL31686A patent/IL31686A/en unknown
  • 1969-02-26 DE DE19691909701 patent/DE1909701A1/de not_active Withdrawn
  • 1969-02-27 NL NL6903035A patent/NL6903035A/xx unknown
  • 1969-03-05 FR FR6905961A patent/FR2003848A1/fr not_active Withdrawn
  • 1969-03-13 NO NO1031/69A patent/NO125291B/no unknown
  • 1969-03-14 GB GB00889/69A patent/GB1268931A/en not_active Expired

Patent Citations (7)

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