Classifications

• • 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
• • C—CHEMISTRY; METALLURGY
  • C06—EXPLOSIVES; MATCHES
  • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
  • C06B25/00—Compositions containing a nitrated organic compound
  • C06B25/32—Compositions containing a nitrated organic compound the compound being nitrated pentaerythritol
• • C—CHEMISTRY; METALLURGY
  • C06—EXPLOSIVES; MATCHES
  • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
  • C06B45/00—Compositions or products which are defined by structure or arrangement of component of product
• • C—CHEMISTRY; METALLURGY
  • C06—EXPLOSIVES; MATCHES
  • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
  • C06B45/00—Compositions or products which are defined by structure or arrangement of component of product
  • C06B45/04—Compositions or products which are defined by structure or arrangement of component of product comprising solid particles dispersed in solid solution or matrix not used for explosives where the matrix consists essentially of nitrated carbohydrates or a low molecular organic explosive
  • C06B45/06—Compositions or products which are defined by structure or arrangement of component of product comprising solid particles dispersed in solid solution or matrix not used for explosives where the matrix consists essentially of nitrated carbohydrates or a low molecular organic explosive the solid solution or matrix containing an organic component
  • C06B45/10—Compositions or products which are defined by structure or arrangement of component of product comprising solid particles dispersed in solid solution or matrix not used for explosives where the matrix consists essentially of nitrated carbohydrates or a low molecular organic explosive the solid solution or matrix containing an organic component the organic component containing a resin

Definitions

• the present invention relates to a novel, self-supporting explosive composition whose density and velocity of detonation may be readily varied by mechanical means, and to a method of fabricating the composition. More particularly, the present invention relates to a deformable self-supporting explosive composition in fibrous form of controllable density and velocity of detonation comprising an intimate mixture of a cap-sensitivecrystalline high-explosive with an elastomeric composition.
• the detonation velocity desired may be as low as 2000 meters per second, as high as 7000 meters per second, or some specific value between these limits.
• the composition should be capable of sustaining a detonation without confinement even in relatively thin cross sections.
• the mechanism for regulating the velocity of detonation of the composition should be one which does not require changes in the formulation of the composition itself.
• a novel, fibrous self-supporting explosive composition in which the detonati'on velocity may be regulated by mechanical means may be formulated from an intimate mixture of 50 to 85% of a cap-sensitive crystalline high-explosive compound with 1 5 to 50% of an elastomer.
• the compositions of this invention may be prepared conveniently and safely by forming a solution of the explosive and the elastomer in a suitable solvent, precipitating the mixture of explosive and elastomer in .fibrous form by introducing the solution into a liquid which is miscible with the solvent but is not a solvent for either the explosive or the elastomer, separating and drying the fibrous precipitate, and mechanically cutting and pressing the composition to the requisite configuration and density.
• a normally fibrous material such as paper pulp, strand-s, or fibers
• the precipitating liquid so that the explosive-elastomer mixture precipitates as a deposit on the normally fibrous material.
• the composition thus formed tends to have a higher tensile strength than does the fibrous, explosiveelastomer composition without the supporting fiber matrix.
• the amount of extraneous fibrous material may constitute up to about 30% by weight of the final composition.
• the suspension of extraneous fibrous material may contain a substantial quantity of finelydivided explosive to impart increased explosive content in the precipitated explosive-elastomer composition.
• the fibrous compositions thus obtained may be mechanically formed, for example by felting techniques, into useful shapes, such as sheets and tubes, and will be self-supporting in any shape or configuration into which they are formed.
• the resultant forms have the cohesiveness, flexibility, and degree of resilience as well as the requisite explosive strength and other properties for use as an explosive.
• the novel explosive compositions are relatively water-resistant and stable under norpreferred embodiment.
• the cap-sensitive high explosive constitutes 5085% of the final composition. It greater amounts of the explosive component are utilized, the final compositions lack the desired degree of cohesiveness and have a tendency to crack, whereas the use of lesser amounts of the high explosive. results in. products which have unreliable detonation characteristics.
• the compositions of the present invention can be initiated in sheet form, or otherwise, by commercially available blasting caps and will. detonate at velocities which may be varied from 1500 to 7500 meters per second. The velocity of the composition will vary directly with the density of the fibrous material, which can be regulated by mechanical means.
• PETN penentaerythritol tetranitrate
• RDX cyclotrimethyl enetrinitramine
• other cap-sensitive crystalline explosives such as other organic nitrates, e.g., nitromannite, and other nitramines, e.g., HMX (cyclotetramethylenenitramine), tetryl, and ethylenedinitramine
• HMX cyclotetramethylenenitramine
• tetryl tetryl
• ethylenedinitramine also can be used.
• a mixture containing such compounds e.g., a mixture of PET-N and TNT or RDX, or a mixture of PETN and a less sensitive compound such. as ammonium nitrate, are suitable.
• a portion or all of'the cap-sensitive explosive used in preparing the fibrous'lcomposition of the presentinvention may be added as a suspension in the precipitating liquid in a superfine state, i.e., the maximum dimension of.-the particles are Within the range of 0.1- microns, the average maximum crystalline dimension beingwithin the range of 0.1 and 2 microns.
• the use of the superfine material increases the impact and cap sensitivity of the fibrous mass, for example, as determined: by thestandard drop test with a S-kg. weight or the minimum primer test.
• the non-explosive binding material consists of the elastomer and, if desired, the extraneous fibrousmaterial. Increasing the proportion of elastomer Within certain limits increases the resilience of the explosive composition. However, if the elastomer constitutes more than 50% by weight of'the composition, the product mass will not reliably propagate a detonation. On the other hand, the use of less than 15% of the b inding materials gives a composition which is difiicult to form and lacks the desired strength and cohesiveness.
• Any elastomeric material such as natural or synthetic rubbers, rubbery plastics andpo lymers and the like which are chemically inert with the system and soluble in a solventfiorthe explosive and insoluble in the solvent-miscible precipitating liquid may be used in preparing the composition of the present invention.
• the elastomer must not contain elements or compounds, such as allcaline constitu ents, aliphatic or aromatic amines, or strong mineral acids, which will react with the explosive composition to effect a degradation thereof nor must it be of a nature to react with thesolvent medium atthe expense of its elastomeric properties so that a friable or hard precipitate is formed by the reaction.
• Ketone e.
• elastomeric materials are especially convenient and represent a much Exemplary elastomeric materials include butadiene-acrylonitrile copolymers available as Hyoar (manufactured by the B. F. Goodrich Co.) or as aracril (rruanufactured .by the Naugatuck Chemical Division of the U. S. Rubber Co.); :cop'olymers of vinylidene fluoride and hexafiuo-ropropylene (commercially available as Viton, manufactured by E. I. du Pont de Nemours and 00.); chloroprene polymers (commercially available as neoprene, manufactured !by E. I.
• the elastomeric material is used for its rubbery nature and not because of any chemical property lOI' characteristic. So long as the elastomeric material is substantially chemically inert to the system (i.e., will not react with the explosive to desensitize it, will not degenerate or degrade in solution, etc.), it is satisfactory for purposes of the present invention regardless of its chemical structure.
• plasticizers or modifiers such as ⁇ as cellulose acetate, vinyl chloride-vinyl acetate copolymers and the like may be added to the composition to the extent that the additive is chemically inert with the system.
• a normally fibrous material which may constitute 05-30% by weight of the fully tormul-ated composition, usually enhances the tensile strength of the composition.
• concentration of the normally fibrous material is more than 30%, the detonation characteristics of the'composition may deteriorate.
• any suit-able techniques being satisfactory, e.g., pressing with a mechanical or hydraulic press or rolling, etc.
• the method described in the examples is simple and reliable, i.e., precipitating a fibrous mass comprised of the high explosive, an elastomer, and, if desired, a fibrous material, collecting the fibrous mass on a filter to produce the desired explosive weight per unit area, drying the filter cake to a desired moisture content '(bone" dry or slightly moist to minimize springback), and compacting the fibrous mass to a desired density, e.g., by pressing with a mechanical or hydraulic press :or by rolling.
• a thin layer of a pressure-sensitive adhesive may he applied to the surface of the finished product, e.g. the
• sheets may be formed from the composition, the sheets dried, and
• sile strength may reduce its flexibility until, at an amount in excess of 30%, the loss of flexibility'rnay curtail the used, e.g., cotton, rayon, nylon, polyesters, or acrylic I resins, etc.
• any solvent which will dissolve both the explosive component and the elastomeric component and which is miscible with a non-solvent for these components may he used to form these unique explosive compositions.
• the watermiscible solvents such as acetone, methyl ethyl ketone, or dimethyl 'formamide are especially convenient.
• Sufiicient solvent must be used to completely dissolve all of the explosive and all of the elastomer to be precipitated. More than the minimum amount may be used to modify the physical nature of the precipitate, if desired.
• any non-solvent for the exlPlOSlVC land the elastomer which also is miscible with the solvent used may be employed. Because of its [low cost, water is preferred if the solvent is water-miscible. The quantity required is that which will dilute the solvent sufli- "ciently to precipitate out essentially all of the explosive and the elastomer.
• the fibrous precipitate may be recovered from the slurry by conventional means, such as filtration, and dried.
• dry fibrous composition can be used without rfurther treat ment.
• the composition In this loose, unpressed state, the composition has its lowest density and its minimum (or initial) detonation velocity. Compressing the composition to densify it increases the velocity of detonation of the composition.
• Auxiliary agents such as reinforcing :agents, pigments, dyes, and the like may be incorporated in the explosive compositions of this invention to the extent that the composition is not unduly impaired with respect to its density or detonation velocity.
• the sheet could he initiated by'a I No. 6 electric blasting cap and the velocity of detonation i electric blasting cap, the velocity of detonation was 7260 meters per second.
• EXAMPLE 2 pressed c-ake initially prepared in Example 1.
• the sheet had a density of 0.58 gram per cubic centimeter.
• the sheet was initiated by a No. 6 electric blasting cap and 'had a detonation velocity of 3815 meters per second.
• EXAMPLE 3 A solution of 19.8 parts of the vinylidene fluoride-hexafiuoropropylene copolymer of Example 1 and 46 par-ts of PETN in 198 parts of acetone was poured into a beaker containing 350 parts Water with stirring. The flocculent precipitate which formed was collected on a 9% inch diameter Biichner funnel and the precipitate air dried :at 100 F. The fibrous dry sheet was approximately 0.6 centimeter thick, weighed 0.94 gram per square inch, and had a density of 0.24 gram per cubic centimeter. When a portion of the sheet was initiated by a conventional No. 6 electric blasting cap, the velocity of detonation was 2160 meters per second.
• EXAMPLE 4 A fibrou ssheet comprising a 50/ 50 mixture of PETN and the vinylidene fiuoride-hexafluoropropylene copoly- .mer of Example 1 was prepared by the method described EXAMPLE 5 A mixture of 80 parts PETN, 15 parts butadie-ne-acrylonitrile copolymer having anintermediate acrylonitrile content (approximately 25 a specific gravity of 0,97 and a Mooney viscosity of 50-60 (Paracri1 BI) and 5 parts cellulose acetate wasdissolved in acetone, and the resulting solution was jetted through a capillary tube into a Waring Blendor containing 400 parts water revolving at low speed.
• EXAMPLE 5 A mixture of 80 parts PETN, 15 parts butadie-ne-acrylonitrile copolymer having anintermediate acrylonitrile content (approximately 25 a specific gravity of 0,97 and a Mooney viscosity of 50-60 (
• the precipitate which formed was filtered onto a 4 /zinch diameter Biichner funnel and the filter cake dried at 100 F. to form a sheet which weighed 1 gram per square inch and had a densi-ty of 0.22 gram per cubic centimeter.' The sheet was strong and flexible and detonated at 2350 meters per second.
• EXAMPLE 6 A solution of 27.8 parts of PETN and 12.85 parts of a low-temperature polymerized acrylonitrile-bu-tadiene elastomer containing a high percentage (approximately 40%) of :acrylonitrile and having a specific gravity of 1.00, Mooney viscosity of 70-95 (Hycar 1041) in and flexible and could be bent around apipe of /2 inch radius without breaking. The sheet could be initiated by a No. 6 electric blasting cap, and the velocity of detonation was 2615 meters per second.
• EXAMPLE 7 A number of compositions were prepared by the method of Example 6 from PETN, a low-temperature polymerized acrylonitr-ilebutadiene elastomer of Example 6 (Hycar 1041) and the paper pulp. In these compositions the proportion of paper pulp was varied while the ratio of PETN to elastomer was maintained at 12/36. The following table summarizes the properties of the sheets prepared from these mixes.
• a fibrous composition comprising a 70/33.5/7.5 mixture of PETN/low-ternperature polymerized acrylonitrilebutadiene elastomer containing 35-40% of 2083 meters per second. Portions of the original sheet 700 parts acetone was jetted into a suspension of 27.8
• EXAMPLE 9 i A solution containing 24 parts PETN and 5.6 parts of a low-temperature polymerized acrylonitrile-butadiene elastomer containing 35-40% acrylonitrile (Hycar" 1041) in 400 parts acetone was allowed to drip into a stirred suspension of 2.4 parts paper pulp in 2 liters of water. The precipitated fibrous mass was collected on a :4 /2 inch diameter Biichner funnel and the filter cake dried at F. The fibrous sheet formed weighed 2 grams per square inch and had a density of 0.33 gram. per cubic centimeter.
• Hycar low-temperature polymerized acrylonitrile-butadiene elastomer containing 35-40% acrylonitrile
• Thesheet was cut into five segments and tour of these segments were compressed by using a conventional mechanical press (an Arbor press) to thicknesses corresponding to the densities shown in the following 7 table. Each of the five segments was initiated by a No. 6 cap and the velocity of detonation measured.
• EXAMPLE 12 An acetone solution of 2.0 parts of the acrylonitrilebutadiene copolymer of Example 5 (Par-acril BI) and 0.8 part cellulose acetate was jetted into an aqueous dispersion of 12 parts superfine PETN and 1.2 parts paper pulp stirred at high speed, and the fibrous precipitate formed was filtered onto :a Biichner funnel and dried at ambient temperature to give a felt-like sheet which had a density of 0.39 gram per cubic centimeter. In the standard drop test (5 kg. weight), the detonation point of the sheet was 6 inches. The detonation velocity of the sheet was 2670 meters per second and the sheet could be initiated by a No. 6 cap.
• EXAMPLE 13 A number of mixes were prepared by the method described in Example 12 from PETN and a mixture of paper pulp, the acrylonitrile-butadiene copolymer of Example 5 (Paracril BJ), and cellulose acetate. I In these mixes, the proportions of superfine PETN (suspended in water slurry) to PETN in acetone solution were varied as shown in the following table which summarizes the Properties of the sheets prepared from these mixes.
• EXAMPLE 1s A slurry of 6 parts superfine PETN and 1.2parts paper pulp in 70 .parts water was mixed with tan acetone solution of 6 parts- PETN, 2.7 parts of the acrylo-nitrile/butadiene elastomer of Example 6 (Hycar 1041) and 1 part of a polyether plasticizer, di butoxyethoxyethyl formal (commercially available as TP- --B, manufacturedqby Thiokol Chemicals) in a. Waring Blendor at slow The precipitate obtained was collected on a 4 /2 inch Biichner funnel and dried at" F. The sheet prepared had a density of 0.44 gram percubic centimeten'and had an impact sensitiveness as determined by the standard drop test (5 kg.
• the sheet could be initiated by-ia No. 6 electric blasting .jcap, and the'velocity of detonation was 2820 meters/second".
• the velocity of'detonation when the sheet was initiated by a No. 6 cap was 6350 meters per second.
• the sheet was flexible even at temperatures as low as 15 F. v r
• EXAMPLE 18 A solution of 52.5 parts RDX and 12.25 parts of the acrylonitrile-butadiene elastomer of Example 6 in 1000 parts acetone was jetted into a suspension of 5 .25 parts paper pulp dispersed in 2000 .parts of Water with agitation. The precipitate was filtered :onto a 9% inch Biichner funnel, excess liquid removed by suction and the filter cake dried at 100 F. The dry filter cake was approximately 0.12 inch in thickness, had a density of 0.52 gram per cubic centimeter and weighed 1.005 grams per square inch. The sheet was strong and flexible and detonated at 2810 meters per second when it was initiated by a No. 6 electric blasting cap.
• EXAMPLE 19 A solution of 52.5 parts HMX and 12.25 parts of the elastomer of Example 6 in 2670 parts acetone was added in a small stream to 5000 parts water with stirring simultaneously with a dispersion of 5.25 parts paper pulp in 2000 parts water. The flocculent precipitate was collected on a Biichner funnel and dried at 100 F. The resulting filter cake was 0.31 cm. thick and had a density of 0.48 gram per cubic centimeter. The sheet was strong and flexible. When the sheet was initiated by a No. 6
• EXAMPLE 20 A solution of 52.5 parts PETN and 12.25 parts of a low temperature polymerized acrylonitrile-butadiene elastorner of Example 6 in 1000 parts acetone was dripped into 5000 parts of water with stirring. While simultaneously, a parallel stream of a suspension of 5.25 grams of unbleached kraft paper pulp in 2000 parts of Water was added to the water. Approximately one-third of the flocculent precipitate (formed was poured onto a 24-cm. diameter Biichne-r funnel, suction was applied, and the solvent removed to produce a soft solid mass.
• a layer of cheesecloth having a diameter approximately that of the tunnel was laid on top of the mass, and one-halt of the remaining flocculent-precipitate was poured on top of the cheesecloth and the solvent removbdll
• An-other layer or cheesecloth was placed on top of the partially dried mass and the remaining portion of the fiocoulent precipitate was poured onto the tEunneL Suction was again applied to remove the solvents and the filter cake was dried at 100 F. overnight.
• the dry filter cake weighed 1.06 grams per square inch, was approximately 0.177 inch in thickness and had a density of 0.37 tgramper cubic centimeter. The tensile strength of the sheet was excellent. When initiated by a No. 6 electric blasting cap the sheet detonated at a velocity 2456 meters per second.
• EXAMPLE 22 A solution of 70 parts P-ETN, 20 parts of the acrylonitrile-butadiene elastomer of Example 6, 6 parts cellulose acetate and 4 parts of Ai-inch strands of Dacron in 400 parts of acetone was poured into water in a Waring Blendor. The resulting precipitate was collected on a Biichner funnel and dried overnight at 100 F. The filter cake was strong and had a density of 0.215 gram per cubic centimeter and a velocity of detonation of 2480 meters per second.
• a fibrous, 'felt-like explosive compressible composition having a variable density and detonation velocity comprising about from 50 to by weight of capsensitive, crystalline high explosive selected from the group consisting of organic nitrates and nitramines and about from 15 to 50% by weight of rubbery elastomeric polymeric binding material therefor in fibrous form, said binding material being soluble in a water-miscible solvent and chemically inert with the system.
• a fibrous, felt-like explosive composition comprising about from 50 to 85% by weight of cap-sensitive, crystalline high explosive seleced from the group consisting of organic nitrates and nitra-mines and about from 15 to 50% by weight of elastomeric polymeric binding material therefor in fibrous form, said binding material being chemically inert with the system, soluble in water miscible solvent and selected from the group consisting of natural rubber, buta'diene-acrylomitrile copolymers, vinylidene fluoride-hexafluoropropylene copolymers, chloroprene polymers and methacrylonitrile-butadiene copolymers.
• An explosive composition of claim 2 wherein said cap-sensitive, crystalline high explosive comprises pentaerythritol tetrani-trate.
• An explosive composition of claim 2 wherein said cap-sensitive, crystalline high explosive comprises cyclotrimethylenetrinitramine.
• a non-woven, felt-like sheet of an explosive composition of claim 2 containing additionally about from 0.5 to 30% by weight of a normally fibrous substance selected from the group consisting of natural and synthetic fibers.
• a method of preparing an explosive composition in sheet form which comprises dissolving about from 50 to 85 parts by weight of cap-sensitive, crystalline high explosive selected .from the group consisting of organic nitrates and nitramines and about from 15 to 50 parts by weight of elastomeric polymeric binding material therefor in a mutual solvent miscible with water, said binding material being chemically inert With the system and selected from the group consisting of natural rubber, butadiene-acrylonitrile copolymers, vinylidene fluoridehexafluoropropylene copolymers, chloroprene polymers and methacrylonitrile-butadiene copolymers, dispersing the resulting solution in water to coprecipitate said explosive and elastomeric binding material as a fibrous mass, collecting the fibrous precipitate and compressing said fibrous precipitate into a sheet.
• said water contains about from 0.5 to 30% by weight of a dispersed, watera finely dispersed mixture of said fibrous substance and cap-sensitive, crystalline high explosive having maximum crystallite dimensions in the range of 0.1 to 100 microns,
• the average thereof being within the range of 0.1 to 2 microns.

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Citations (4)

• 1961
  • 1961-03-07 US US93852A patent/US3102833A/en not_active Expired - Lifetime
• 1962
  • 1962-03-05 SE SE2412/62A patent/SE306265B/xx unknown
  • 1962-03-05 GB GB8370/62A patent/GB950144A/en not_active Expired
  • 1962-03-06 LU LU41330D patent/LU41330A1/xx unknown
  • 1962-03-06 BE BE614729A patent/BE614729A/fr unknown
  • 1962-03-07 AT AT189062A patent/AT251460B/de active

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