MXPA00002249A - Flares having igniters formed from extrudable igniter compositions - Google Patents

Abstract

The present invention relates to flares and other solid propellant devices, rockets or the like, equipped with an igniter or igniter system which is based in whole in part on an extruded igniter stick. The extruded igniter stick is formed from constituents comprising a water-soluble or water-swellable binder, at least one oxidizing agent, at least one fuel, and optionally, fibers.

Description

BENGALS THAT HAVE IGNITION DEVICES FORMED OF EXTRIBLE COMPOSITIONS OF IGNITION DEVICE BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to extrudable ignition compositions, and to ignition rods extruded therefrom, in combination with flares or other solid propellant devices, such as rockets or the like. 2. Information Background The ignition compositions must satisfy numerous design criteria. When the ignition composition is formed, it must be sufficiently robust to remain operable prior to the development of the device to be ignited, such as a flare or other device. One of the proposed ignition systems commonly uses solid particles consisting of B / KN03 which, when ignited, initiates combustion of the specified gas generating composition. REF. 33007 Other recent efforts in the civilian market have focused on developing alternative ignition compositions effective in terms of costs or ignition compositions which can be manufactured more easily. These efforts have included proposals to use a thermoplastic resin matrix fused by heat together with a particular ignition composition, such as KN03. This effort seeks to join a commercially available heat-melt adhesive, for example one designated for what are called "glue-guns" with a common alkaline metal oxidizer. This effort to improve performance has been less than satisfactory. Extrusion capability and ignition performance prove to be difficult to control and the repeatable ballistic performance that is desired has not yet been demonstrated. Consequently, despite these and other additional efforts, the relevant objectives remain unresolved. A simpler and more cost effective ignition composition for flares and decoys or other devices still remains a wish. In particular, they are still making efforts to provide an ignition composition which avoids the need to heat melt the so-called adhesives, and therefore, the consequent risks associated with the processing of a pyrotechnic material at an elevated temperature, but which be easy to manufacture and be sufficiently robust. Therefore, it would be a significant advance to provide ignition compositions capable of being used as an ignition or ignition device which satisfactorily solves these concerns in the industry.

BRIEF DESCRIPTION AND OBJECTIVES OF THE PRESENT INVENTION The present invention provides flares, solid propellant rockets, decoy devices and the like that incorporate one or more of the ignition rods described herein. The extrudable ignition device is easily manufactured at low cost to obtain a physically robust product. The ignition device can be manufactured without the use of melt mixing or hot melt thermoplastic equipment and thus avoids the potential hazards associated with processing at such elevated temperatures. The extrudable ignition composition from which the ignition rod can be formed is suitably processed at ambient temperatures in robust products which have sufficient relatively selectable ignition characteristics. The ignition bar may have other configurations, with the proviso that the configuration is consistent with the objectives described herein. The exstrudable ignition composition can be used to form a solid or hollow ignition "bar" capable of initiating a light signal or flare or a propellant composition in a flare or other pyrotechnic device.

SHORT DESCRIPTION OF THE DRAWING Figure 1 illustrates an exemplary flare device (a flare type XM212) in longitudinal cross section which includes the ignition or ignition bar formed from an extrudable ignition composition. Figures 2, 3, 4 and 5 illustrate diametral cross-sectional views of flares that are provided with the ignition rods fabricated from the extrudable ignition composition described.

DETAILED DESCRIPTION OF THE INVENTION The extruded ignition bars can be characterized because they have a configuration designed for rapid high-temperature deflagration when ignited. When igniting an ignition bar, it is capable of igniting another pyrotechnic composition. In flares, such as flare XM212, the ignition rods are sized to be capable of complete end-to-end ignition, for example complete flame transition, in a short time, for example less than 10 milliseconds. Ignition compositions which are capable of being extruded are characterized in that they can be obtained from a combination of a binder, a soluble or water dispersible oxidizing agent, a fuel soluble or dispersible in water and a selected amount of water. Preferably, the extrudable compositions are essentially homogeneous in composition. The binder, by its current preference, is a water-soluble binder, although binder materials expandable in water are not excluded provided that the remaining solid constituents of the ignition or ignition device are homogeneously distributable substantially sufficiently in the same. Typical binders used in the present ignition composition include, by way of example, water-soluble binders such as poly-N-vinylpyrrolidone, polyvinyl alcohols and copolymers thereof, polyacrylamide, sodium polyacrylates, copolymers based on acrylamide or acrylate. sodium, gums and gelatin. These water-soluble binders include naturally occurring gums, such as guar gum, acacia gum, modified celluloses and starches. A detailed discussion of "gums" is provided by C.L. Mantell, The Water-Soluble Gums, Reinhold Publishing Corp., 1947, which is incorporated herein by reference. It is currently considered that water-soluble binders improve mechanical properties or provide improved compressive strength. Although water-immiscible binders can be used in the present invention, it is presently preferred to use water-soluble binders in combination with fuels and / or oxidants suitable for use in the formulation of an ignition device. Suitable fuels and oxidants can be soluble or insoluble in water. Suitable fuels and oxidants can be inorganic or organic. In the formulation from which the extruded ignition rod is formed, the concentration of binder is such that a sufficiently robust extrudate is obtained mechanically. The extrudate, such as an ignition rod, may be able to retain its shape, for example maintaining its integrity, before ignition. Preferably, the extruded ignition bar is capable of being received (inserted) into a pyrotechnic composition, for example a properly configured perforation (for example a central perforation) in a propellant composition, and fragmentation or fracture when ignited. In general, the binder may be in the range, for example, from about 2% by weight to about 10% by weight, and more particularly about 3% by weight to about 7% by weight, based on the dry ingredients in the formulation. The binder can be made up of more than one binder material. The ignition composition includes at least one oxidant, which preferably is soluble in water or at least dispersible in water. Therefore, the oxidant may be organic or inorganic, although inorganic oxidants are currently preferred. The organic oxidants which are dispersible in a binder so that a sufficiently homogeneous ignition composition can be obtained include salts of amine nitrate, nitro compounds, nitramine, nitrate esters and amine perchlorates, of which the methylammonium nitrate and the methylammonium perchlorate are exemplary. Other candidates include RDX and HMX, CL-20 and PETN. Inorganic oxidants include oxidizing ionic species such as nitrates, nitrites, chlorates, perchlorates, peroxides and superoxides. The typing of these inorganic oxidants are metal nitrates such as potassium nitrate or strontium nitrate, ammonium nitrate, metal perchlorates such as potassium perchlorate and metal peroxides such as strontium peroxide. In general, the oxidant is usually present in an amount effective to ensure oxidation of at least the fuel in the ignition or ignition device, and may be in the range, for example, from about 40% by weight to about 90. % by weight, and more particularly about 70% by weight to about 85% by weight, relative to the dry ingredients in the formulation. The ignition composition can be formulated with an additional fuel, assuming that the binder may be able to function as a secondary, non-primary fuel for the ignition composition. These additional fuels include powdered metals such as powdered aluminum, zirconium, magnesium and / or titanium, among others.; metal hydrides such as zirconium or titanium hydride; and the so-called metalloids such as silicon and boron, which are capable of being sufficiently "dispersible" in the binder. Water-soluble or water-dispersible fuels include, for example, guanidine nitrate, cyano compounds, nitramines (RDX and / or HMX), CL-20, tetranitrocarbazoles, organic nitro compounds and, if desired, can be "multimodal" in the particle size distribution. Water dispersible materials can be added in a substantially uniform particle size distribution or in multimodal distributions, depending on the desired ignition characteristics.

The water dispersible fuels, as current preference, are used in fine particulate form, such as powder or crushed to fine enough particles to ensure adequate distribution during the manufacturing process. Preferably, at least one substantially uniform distribution is desired in the resulting extrudable ignition composition. In general, the fuel is in powder form, for example as 100 μ or less, such as, for example, from about 1 μ to 30 μ. The materials in powder form can have, if desired, a smaller particle size range, for example from about 1 to 20 μ, or even smaller, such as 1 to about 5 μ. The amount of fuel - other than the binder - may be in the range, for example from about 5 to about 30% by weight, and more particularly from about 10% by weight to about 20% by weight relative to the dry ingredients in the formulation. The present ignition rods can incorporate, if desired, a reinforcement. Suitable reinforcements can be obtained with fibers, such as combustible fibers, which serve to reinforce the extruded ignition rod and, upon proper selection of the reinforcement, can improve the operation of the ignition device. The present ignition rods and related grains may incorporate, if desired, a reinforcement. Suitable reinforcement can be obtained with fibers, such as combustible fibers, which can serve to reinforce the extruded ignition bar and, upon appropriate selection of the reinforcement, improve ignition performance. The fibers are preferably of shorter overall length (low dimensional ratio). The fibers incorporated in the extrudable ignition formulations include, for example, polyolefin fibers, polyamide fibers, polyester fibers and poly (2, 2- (-phenylene) -5,5-b-benzimidazole fibers ("PBI"). The polyolefin fibers include polyethylene ("PE") fibers, such as PE fibers having an outer diameter of about 0.005 mm and greater, such as about 0.8 mm, and a length in the range of 0.1 mm to about 3.2 mm, of which Allied-Signal's Spectra 900 polyethylene brand is illustrative.Appropriate polyamide fibers such as nylon 6 fibers, can suitably have a selected diameter, such as 19 micrometers, and a length of 1.5 mm to about 6.4 mm Suitable polyester fibers include high tenacity polyester fibers having lengths from about 1.5 mm to about 6.4 mm, and a suitable diameter of about 25 microns. s PBI include those that have lengths in the order of 0.8 mm to 3.2 mm. The representative reinforced ignition rods and the formulations for the same are reported in the examples.

The present cc% sg > otion in extrudable form can be easily obtained, for example, by mixing the binder, the fuel, the oxidant and a selected water * for a period of time to obtain an at least substantially uniform distribution of the fuel, it is used, and an oxidant through the binder The method involves mixing a water-soluble binder and a selected amount of water to form a premix, and mixing the premix with: (a) first the fuel and then the oxidant, or (b) the oxidant and then the fuel, or (c) a combination of the oxidant and the fuel.The amount of water is generally such that the resulting product has a consistency which is extrudable, but preferably does not drip. They can use larger amounts of water but there may be some manufacturing concerns, including an increase in waste water thrown up with varying amounts of water. pyrotechnic ecies (fuel, oxidant, etc.). The ignition composition formed in this way is capable of being extruded to the desired physical geometry. The ignition rods can be used in combination with solid propellant rockets or other devices which require ignition of solid propellant. Other devices include, without limitation, flares. Among the suitable flares are those known to those skilled in the art as rocketing flares of which the flare MJU-10 is exemplary. Other flares such as the M-206 flares (which may or may not be spectrally incident) or a near-IR flare, such as the M-278 flare, are also properly combined with one or more ignition rods. Suitable flares are not restricted to the flares mentioned above MJU-10, M-206 or M-278. For example, what is called a standard 70mm (2.75 inch) flare (diameter in cross section) includes visible lighting flares, and is adequately provided with at least one ignition bar. Non-commercial flare variants of the standard flare have not been adequately provided, such as the M-257 type flare with one or more ignition rods. Advantageously, the ignition bar lowers costs, decreases manufacturing time and simplifies the design of the flares, including the ignition system for a propeller flare such as the MJU-10 flare. The ignition rods can be used in a large number of decoy devices which include decoy flares which are deployed to defend against incoming hazards, and particularly against heat-directed missiles. The ignition bar or bars improve the reliability of flare ignition by decreasing the first off-site fire and the safety of manufacturing flares by eliminating the use of flammable solvents commonly used when the first traditional fires are applied. Suitable flares and / or flare compositions for combination with at least one igniter bar are described in Encyclopedia of Chemical Technology, 20: 80-697 (4th ed, 1996), which includes the reference mentioned herein, full description of which is incorporated herein by reference. Ignition rods can be used with larger solid propellant launch vehicles, such as solid propellant rockets. In these larger and more complex systems, the ignition bar can be used as part of an ignition system, for example as the initiator in the pyrotechnic train to propagate or initiate the propagation of the ignition. Solid propellant rockets which can be equipped with at least one ignition bar are at least part of the ignition system and include those described in Solid Rocket Proplsion Technology (Pergamon Press, lst Edition 1993), and Rocket Proplsion Elements ( Wiley Interscience, 4th Edition 1976), whose full descriptions are incorporated by reference. The well-known Jane's Handbook describes flares and other solid propellant devices used properly in combination with ignition rods. Extrusion and extruders are generally described in Encyclopedia of Polymer Science and Engineering, 16: 570-ß3t * _ (ed. Edition 1996), which includes references mentioned herein, the full disclosure of which is incorporated herein by reference. Figure 1 illustrates, in cross-section, a type of flare known as flare XM212. In a longitudinal cross-sectional view, the cover is a suitable pressure enclosure made of steel or other material capable of being used for a flare application. The cartridge cover 18 may have a housing 17 with ventilation. A closed end is defined by the front enclosure 19. The opposite end of flare XM212 includes a front lock 212, spacers 13, an ignition system with ignition device 15, a protective cover 10 and a piston 11. In a preferred embodiment, a solidified (extruded) ignition bar 16, which may be solid or hollow, extends longitudinally (fully or partially) ) through the propellant grain as shown in Figure 1. The ignition rod can be formed by extruding the extrudable ignition composition described above, allowing the extrudate to solidify, and inserting it into a propellant grain (preferably before it is cured). ). A selected propellant composition 14 surrounds the ignition bar. If desired, what is referred to as a rapid deflagration rope, for example, loosely covered within a hollow ignition bar can be placed longitudinally. But not It is illustrated, if desired, to use more than one ignition bar. The "diametral" cross-sectional views of flare cartridges with propellant and ignition rods are shown in Figures 2-5. In the diametral cross-sectional view of Figure 2, the flare cartridge 28, if desired, may have a foam layer 22 (eg, a foamed nitrocellulose coating) sprayed onto its inner surface before the propellant is charged 24. A central bore having a preselected geometry 26 surrounds the hollow ignition bar 20 (in its extreme view such as a quargum binder / B / KN03). In the diametral cross-sectional view of Figure 3, the flare cartridge 38 has been loaded with the propellant 34 and is provided with a centrally placed hollow ignition bar 36. Optionally, additional solid or hollow ignition rods 32 can be provided. In the diametral cross-sectional view of Figure 4, the flare cartridge 48 is loaded with the propellant 44 and a perforation in the centrally placed shape of the preselected geometry. The centrally placed perforation can have an ignition bar 42 with ignition bars 46 (in the form of a strip) placed radially in the grooves from the perforation. They are located inside the slots and preferably loose. In the diametral view of Figure 5, the flare cartridge 58 is shown loaded with a propellant 54 and a centrally placed ignition bar having axial bore holes therein. The ignition bar, if desired, can be placed with a release liner / sleeve prior to insertion into the propellant grain. This can protect the ignition bar during the manufacturing process or during storage before use. The ignition rods are preferably inserted into the propellant grain before the latter is cured. The ignition compositions are described in the full application of the United States copendiente number filed on July 21, 1998 (file 97-08-SE-01), whose full description is incorporated herein by reference. The invention is further described with reference to the following non-limiting examples.

*. EXAMPLES Example 1 In a 3.8-liter (one gallon) Baker-Perkins planetary mixer, 1170 g (78%) of 35 micron potassium nitrate and 105 g (7%) of Cytex Cyanamer1 ^ N-300 brand polyacrylamide (15 molecular weight) are added. millions) . These ingredients are then mixed remotely in the dry state for one minute. To this mixture, 217.5 g are added (14.5 parts per 100 of ignition device formulation) of water, and mixed for five minutes. The blades of the mixture and the inner surface of the mixing bowl are scraped with Velostat spatulas (conductive plastic) followed by an additional 15 minutes of mixing. To the resulting thick white paste is added 225 g (15%) of amorphous boron powder (purity of 90-92%) and mixed remotely for five minutes. While the approved protective fabric is being prepared for wear, the blades and bowl are again "scraped" manually and the formulation mixed for an additional ten minutes. The resulting brown material, similar to dough, is granulated to a ~ 4 mesh and fed to an extruder 'single screw Haake 25 mm. The ignition device formulation is extruded through a 12-point star-shaped die with a maximum diameter of 8.4 mm (0.33") and a minimum diameter of 7.6 mm (0.30"). The die includes a bolt with a central diameter of 2 mm (0.080"), thus producing a hollow rod-like configuration.The ignition formulation is cut into lengths of 18 cm (7"). Before drying, a length of 19 cm (7.5") and 1.8 mm (0.07") in diameter. Teledyne RDC (fast deflagration rope) is inserted into the 2 mm (0.08") diameter bore.The ignition rods are dried at 74 ° C (165 ° F) overnight.The ignition rods are tested for evaluate its operation as an ignition device in an inflator which is designed for automotive safety bags on the passenger side.The ignition bars work satisfactorily.

EXAMPLE 2 A series of extruded stick bar formulations containing boron, potassium nitrate and water-soluble binder, and optionally fibers for reinforcement are prepared. These formulations are reported in Table I. The formulations are first mixed on a 10 g scale and after 30 g to determine their sensitivity to stimuli that include impact, friction, electrostatic discharges and heat (Table II). In general, carbohydrate-based binders show the highest sensitivity with respect to ABL friction. Formulations containing methylcellulose, guar gum and locust bean gum as the binder are also used to prepare the ignition rods. The remaining formulations are mixed at a 325 g scale in a Baker-Perkins planetary mixer of 473 ml (one pint). The potassium nitrate and the respective water-soluble binder are combined remotely in the dry state for one minute. To this combination, the respective amount of water is added (table III) and the suspension is mixed for five minutes. As in example 1, the bowl and the blades are "scraped". At this point, the fibers are added to the formulations containing fiber and the dough is mixed for an additional five minutes. All formulations are mixed for an additional ten minutes before adding boron. Half of the boron is added at this point followed by five minutes of mixing. The remaining boron is then added followed by an additional five minutes of mixing. After a "scraping" at the end, the formulation is mixed for an additional ten minutes. The resulting dough-like, coffee-like material is granulated to ~4 mesh and fed into a 25 mm Haake single screw extruder. The ignition formulation is extruded through a twelve-point star die with a maximum diameter of 8.4 mm (0.33") and a minimum diameter of 7.7 mm (0.305"). The die includes a centrally located 2mm (0.80") diameter bolt.The extruded ignition formulation is cut into 17.8cm (7") lengths. Before drying, Teledyne RDC (rapid deflagration rope) of length 7.5 inches and 1.8 mm (0.07 inches in diameter) is extruded, ten additional lengths of 5.1 mm (2 inches) are extruded. They are dried at 74 ° C (165 ° F) overnight.The important factors for determining useful formation include grain quality after drying, actual operation as an ignition device and drying rate.Leaching of a mixture of KN03 and Binder to the surface of the grain may occur for some formulations during drying.Lapper leaching is not desired.Lexylation is found to be less important in formulations containing tragacanth gum, Cyanamer ™ A-370 and Cyanamer * P-21 (Table III) The ignition rods from formulations containing Cyanamer * A-370 and Cyanamer ™ P-21 are evaluated in content with an inflator device Relative drying rates of 10: 1.7: 1 are calculated for formulations containing Cyanamer ™ N-300, Cyanamer * P-21 and Cyanamer ™ A-370, respectively. Therefore, the formulation containing Cyanamerm A-370 is shown to dry quickly, with minimal leaching of KN03, which produces a grain that ignites generant gas with minimal ignition delay.

It is important to || p? ¡ß.ar extruded ignition rods for flares and other solid propellant devices that withstand decades of shock and vibration while stagnating service before deployment. Therefore a durability test méfegjjp was developed for the extruded ignition bars. The durability tests were carried out in 3-point bending, with the load applied in the middle part. The bending is selected since the compression and cutting tension forces are present. In addition, a configuration demonstrates itself and leads to this type of load. A 38 mm (1.5 inch) offset is used with the applied loads using pin bolts from 3.2 mn to 6.4 mm (1 / 8-1 / 4 inch). A nominal preload of 318 g (0.7 pounds) is applied. The sample is then subjected to 1, 000 charging cycles with the following conditions: cyclical amplitude of 0.076? Tm (0.0003 inches), frequency 10 hertz. After cyclic loading, the samples are tested to determine faults at a displacement speed of 5.1 mm (0.2 inches) per minute. The durability of each sample is reported as the area under the load-displacement curve. For simplicity, the units are maintained as they are calibrated (load in pounds-force, displacement in thousandths of an inch.) Therefore, the durability reported has units of thousandths of an inch-pounds.All the tests were performed at ambient laboratory temperature ( 24 ° C + 2.8 ° C (75 ° + 5 ° F) The results of the durability test indicate improved durability of formulations of extruded ignition system containing fibers, for example formulations # 13 and # 15 in the table III. t t L? o Ul O Ü1 Table 1 Ejenplos of ignition formulations designed for extrusion with water t > J 1Cyanamer is a registered trademark of Cytec Industries Inc., for specialty polymers of polyacrylamide, sodium polyacrylate or copolymers thereof.

Table 2 Safety characteristics of extruded ignition formulations to to H Ul or Ul O Ul t Ul 1The units are in centimeters 2The units are in pounds to o H Ul Ul Table III Summary of test results for extruded ignition devices t 'Parts per 100 of water added to the formulation necessary to allow efficient extrusion by simple thyme. 2The units are in one thousand inches-pounds 3The percentage of blocked holes is determined from six or more bars of 8.4 mm (0.33") outside diameter, 2 m (0.08") inside diameter, and t . 1 cm (2") in length 4 Formulation 9 does not extrude very well A series of firing devices containing fibers are formulated with the purpose of improving the durability of the extruded ignition rods, as shown in Table IV. All the formulations show favorable safety characteristics. 325 g samples of each formulation are mixed in a 453 ml Baker-Perkins mixer (clamp) with 13.5 parts / 100 of water. After drying by combined KN03 and Cyanamer "A-370 for one minute, water is added followed by mixing for five minutes.The fiber is then added in two increments and the boron in three increments with three minutes of mixing after each addition. After a final "scraping", the formulation is mixed for an additional ten minutes.The resulting brownish-like mass material is granulated to -4 mesh and fed into a 25 mm Haake single screw extruder. Ignition is extruded through a 12-pin star die with a maximum diameter of 8.4 mm (0.33") and a minimum diameter of 7.7 mm (0.305"). The die includes a centrally placed 3.8 mm (0.15") bolt. ) diameter. The extruded ignition formulation is cut into 17.8 cm (7") lengths, and ten additional 5.1 cm (2") lengths are extruded. The ignition bars are dried at 74 ° C (165 ° F) overnight.

There are no signs of the KN03 / binder leaching out of the ignition device grains after drying. The beads are ignited by an ignition plume of an ES013 detonator directed to the MlPineral bore of 3.8 mm (0.15") ID (internal diameter) in the grain The ignition grain is held in a 10 mm (0.4") wall ) ID, 12 mm (0.49"), cylindrical placement with approximately 95 holes evenly distributed of 2.8 mm (0.109") ID drilled along its length and diameter. The times necessary for the front of the flame to reach the opposite end of the grain after ignition by the detonator are reported in table V. The times are determined from a video of 1000 frames / second. Generally, some milliseconds are required. The durability of grains 5.1 cm (2") long is determined as described in example 2. The results are reported in table V. By far, the formulation containing 2% polyethylene fibers show the greatest durability. The ignitions are carried out using ignition grains from the formulations # 3 and # 19 with RDC inserted in a perforation of 3.8 mm (0.15"). Formulation # 19 with polyethylene fibers produces the least amount of delay before the pyrotechnic composition is ignited.

Table IV Ignition device formulations containing Cyanamer14 * A- 370 and selected fugaras Table V Summary of test results for potential extruded ignition devices containing fibers 1 Formulation 3 with grains that have 3.2 mm (0.125") ID instead of 3.8 mm (0.15") of nominal ID. 2Time required for the front of the flame in a grain of 18 cm (7") turn on one end to reach the opposite end.The time is in milliseconds.The data is acquired as described in example 3. 3As the foot of note 1, but the cured epoxy material blocks the perforation 3.8 mm (0.15") ID at the opposite end from where the ignition started. 4The units are in mil-pounds.

In the formulations 16, 17, 18, 19 and 20, respectively, "identification of fibers" can be characterized as carbon fiber, alumina fiber, aluminosilicate, polyethylene and polybenzimidazole.

EXAMPLE 4 An extrudable ignition composition is obtained by forming a premix of guar (5.0% by weight, 0.25 grams) and water (deionized, 15.0% by weight, 1.75 grams); combine the premix with potassium nitrate (average particle size of approximately 26 microns, 75% by weight, 3.75 grams); and add to the same fuel, boron (amorphous, 20.0% by weight, 1.00 grams) EXAMPLE 5 An extrudable ignition composition is obtained as in Example 4, but 20.0% by weight of water is used.

EXAMPLE 6 An extrudable ignition composition is prepared as in Example 4, except that the amount of fuel and boron is increased to 22.0% by weight (1.10 grams) and the amount of binder, guar gum, is reduced to 3.0% by weight (0.15). grams).

EXAMPLE 7 An extrudable ignition composition is prepared according to the procedure of Example 4, except that the binder is polyacrylamide (Cyanamer ™ "N-300" from American Cyanamid, 5.0 wt.%, 0.25 grams). ... i .-? * »? Prepare an extrudable ignition mixture at SLf-add 210 grams of potassium nitrate and a polyacrylamide (14 grams; Cyanamer "" N-300"from American Cyanamid) to a bowl, 44.8 grams of water are added to the bowl and mixed during 1 minute; Boron (amorphous, 56.0 grams) is added thereto, followed by mixing for approximately four minutes.

EXAMPLE 9 An extrudable ignition composition is prepared as in example 8, except that the amount of water is 50.4 grams, the nitrate potassium and the binder are first dry combined together, before adding water and mixed for 1 minute. The pulverized boron is subsequently added and the mixture is continued for four minutes.

EXAMPLE 10 The ignition device composition prepared according to Example 8 is granulated, dried and pressed into shots of 13 mm (1/2 inch) in diameter by 2.54 cm (1 inch) in length. The granules are then inhibited on all but one face, and are combusted in a vessel 70, 140 and 211 kg / cm2 (1000, 2000 and 3000 psi) via ignition of the non-inhibited face. Burning speeds of 4.16 ips, 4.32 ips and 4.42 ips respectively are observed.

EXAMPLE 11 A portion of the wet ignition composition prepared as described in Example 9 is placed in a 5.1 cm (2 inch) diameter ram extruder and is used through an appropriate die so as to provide a cylindrical extruded perforated the center approximately 7.6 mm (0.3 inches) in diameter with a perforation with a diameter of approximately 1.5 mm (0.06 inches). This extrudate is partially punched and cut into lengths of 18 cm (7 inches) until final drying. The resulting ignition rods are subsequently tested in a gas generating device consisting of a tubular metal cylinder approximately 20 cm (8 inches) long by approximately 5.1 cm (2 inches) in diameter at both ends and provided with radial holes. One of the end enclosures is further provided with an initiation detonator. The ignition bar is retained in the center of the tube and a rapid deflagration rope (RDC) of 18 cm (7 inches) in length is placed in the central bore of the bar. gas generator is then filled with a load of gas generating grits and with the ignition bar in jßffrcraste with that obtained with a conventional ignition train in which a perforated metal tube filled with an equal amount of ignition powder and RDC replaces the ignition bar / RDC combination. In all cases, the ignition of the gas generating shot occurs within the next 8 msec.

EXAMPLE 12 An amount of two mixtures of 50 grams formulated from 20 percent boron, 75 percent potassium nitrate, 5 percent Cytec Cyanamer * N-300 brand polyacrylamide (molecular weight 15 million) and 17.5 percent 100 percent by weight of water are produced. The mixtures are combined and then loaded into a 5.1 cm (2.0 inch) diameter RAM extruder. The RAM is pressurized to 21 kg / cm2 (300 psi) to extrude the ignition rods. The ignition composition is originally extruded in solid bars of 2.54 mm (0.100 inches) in diameter and also in a diameter of 2.54 mm (0.100 inches) with a central perforation of 0.8 mm (0.30 inches) in diameter. The ignition rods are cut into lengths of 15 cm (6 inches) and dried at 57 ° C (135 ° F) overnight before the ignition rods drilled in the center successively in a decoy flare XM-212. Two XM 212 grains are made. One with the first fire of susp < | 3gÜj > n traditional and the other with three bars of ignition drilled in the center. Figure 1 shows a flare configuration with an ignition bar.

EXAMPLE 13 The ignition bars are also incorporated into the main ignition system of a MJU-10 decoy flare. The MJU-10 flare requires a larger ignition device than the XM-212 flare. Therefore, the ignition device formulation is extruded through a 12-pin star die having a maximum diameter of 8.4 mm (0.33 inches) and a minimum diameter of 7.6 mm (0.30 inches). The extrusion die also includes a 20 mm bolt (0.80 inches) in diameter used to produce a perforated grain. Extruded bars of ignition are cut into lengths of 13 cm (5.0 inches) and dried at 57 ° C (135 ° F) for 24 hours. The ignition rods are then inserted into the central bore of the MJU-10 flare grain. The MJU-10 flare is successfully ignited with the ignition bar.

In view of I above, the ignition bar will lower the cost, decrease the manufacturing time and simplify the design of *? «J! _? ignition system for the MJU-10 propulsive flare. In view of the examples, ignition rods or ignition device rods can be used in a large number of decoy flare devices. They will add and improve the reliability of flare ignition by decreasing the first off-site fire, and also improve the safety of flare manufacture by eliminating the use of flammable solvents commonly used when the first traditional fires are applied. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects or products to which it refers.

Claims (24)

Having described "J" the foregoing, it is claimed as property 14 > held in the following claims:

1. A flare comprising a cartridge, a propellant contained within the cartridge, an ignition system for igniting the propellant, the ignition system includes an extruded ignition element positioned within the propellant, the extruded ignition element is characterized in that it is formed from of a composition comprising, prior to drying the composition, at least one water-soluble binder dissolved in a solvent comprising water, at least one oxidizing agent, at least one fuel and optionally fibers.

2. The flare according to claim 1, characterized in that the water-soluble binder comprises at least one member selected from the group consisting of poly-N-vinylpyrrolidone, polyvinyl alcohol, copolymers of poly-N-vinylpyrrolidone and polyvinyl alcohol, polyacrylamide and sodium polyacrylates.

3. The conformance with claim 2, characterized in that the water-soluble binder comprises poly-N-vinyljjá-krolidone.

4. The flare according to claim 2, characterized in that the water-soluble binder comprises polyvinyl alcohol.

5. The flare according to claim 2, characterized in that the water-soluble binder comprises gum.

6. The flare according to claim 2, characterized in that the water-soluble binder comprises polyacrylamide.

7. The flare according to claim 1, characterized in that the oxidant is present in an amount of about 40% by weight to about 90% by weight relative to the dry ingredients used in the formulation of the extrudable ignition element.

8. The compliance with claim 1, characterized in that the oxidant comprises an organic oxidant. * "1

9. The flare according to claim 1, characterized in that the oxidant comprises at least one ionic species which is selected from the group consisting of nitrate, nitrite, chlorate, perchlorate, peroxides and superperoxides.

10. The flare according to claim 1, characterized in that the extrudable ignition element contains fibers.

11. The flare according to claim 10, characterized in that the fibers comprise at least one of polyolefin fibers, polyamide fibers, polyester fibers or poly (2, 2 '- (m-phenylene) -5,5 fibers. bisbenzimidazole.

12. The flare according to claim 1, characterized in that: (a) the binder comprises at least one member selected from the group consisting of poly-N-vinylpyrrolidone, polyvinyl alcohol, copolymers of poly-N-vinylpyrrolidone and polyvinyl alcohol , Sodium oxidizing polyacrylates is present in an amount from about 40 wt% to about 90 wt% to the dry ingredients used in the formulation of the extrudable ignition element, and the oxidizer contains at least one ionic species which is selected from the group consisting of nitrate, nitrite, chlorate, perchlorate, peroxides and superperoxides; (c) the extrudable ignition element contains fibers of low dimensional ratio, the fibers comprise at least one of polyolefin fibers, polyamide fibers, polyester fibers and poly (2, 2 '- (m-phenylene) - fibers 5, 5-bisbenzimidazole.

13. A method for forming a flare, characterized in that it comprises a cartridge, propellant contained within the cartridge, an ignition system for igniting the propellant. the ignition system includes an extruded ignition element positioned within the propellant, the method comprising dissolving at least one water-soluble binder in a solvent comprising water, and mixing the dissolved binder with at least one oxidizing agent, at least a fuel and optionally, fibers.

14. The method according to claim 13, characterized in that the water-soluble binder comprises at least one member selected from the group consisting of polyvinyl alcohol, copolymers of poly-N-vinylpyrrolidone and polyvinyl alcohol, polyacrylamide and sodium polyacrylates.

15. The method according to claim 14, characterized in that the water-soluble binder comprises poly-N-vinylpyrrolidone.

16. The method according to claim 14, characterized in that the water-soluble binder comprises polyvinyl alcohol.

17. The method according to claim 14, characterized in that the water-soluble binder comprises gum.

18. The method according to claim 14, characterized in that the water-soluble binder comprises polyacrylamide.

19. The method according to claim 13, characterized in that the oxidant is present in an amount of about 40% by weight to about 90% by weight relative to the dry ingredients used in the formulation of the extrudable ignition element.

20. The method according to claim 13, characterized in that the oxidant comprises an organic oxidant.

21. The method according to claim 13, characterized in that the oxidant comprises at least one ionic species which is selected from the group consisting of nitrate, nitrite, chlorate, perchlorate, peroxides and superperoxides.

22. The method according to claim 13, characterized in that the extrudable ignition element contains fibers.

23. The method according to claim 22, characterized in that the fibers comprise at least one of polyolefin fibers, polyamide fibers, polyester fibers or poly (2, 2 '- (m-phenylene) -5,5 fibers. bisbenzimidazole.

24. The method according to claim 13, characterized in that: (a) the binder comprises at least that it is selected from the group consisting of poly-N-vinylpyrrolidone, polyvinyl alcohol, copolymers of poly-N-vinylpyrrolidone and polyvinyl alcohol, polyacrylates of sodium and gum; (b) the oxidant is present in an amount from about 40 wt% to about 90 wt% relative to the dry ingredients used in the formulation of the extrudable ignition element, and the oxidant contains at least one ionic species that is selects from the group consisting of nitrate, nitrite, chlorate, perchlorate, peroxides and superperoxides; (c) the extrudable ignition element contains fibers of low dimensional ratio, the fibers comprise at least one of polyolefin fibers, polyamide fibers, polyester fibers and poly (2, 2 '- (m-phenylene) - fibers 5, 5-bisbenzimidazole. The pressure with flares and other solid propellant devices, rockets or the like, equipped with an ignition device or an ignition system which is based completely or in part on an extruded ignition bar. The extruded ignition bar is formed of constituents comprising a binder soluble in water or expandable in water, at least one oxidizing agent, at least one fuel and optionally fibers.