Classifications

• • 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
  • C06B21/0008—Compounding the ingredient
  • C06B21/0025—Compounding the ingredient the ingredient being a polymer bonded explosive or thermic component
• • 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

• a composite explosive with a rubbery binder comprises particles of explosive material dispersed into a rubbery binder.
• the binder is a carboxylic polydiolefin based resin, the proportion of explosive material amounting to not more than 92 percent by weight of the composite explosive.
• To prepare the composite explosive at least one carboxylic polydiolefin and at least one chain extending agent and/or reticulating agent are mixed with the particles of explosive substance.
• Said agent contains in each molecule at least two functional groups capable of reacting with the -COOH groups in the carboxylic polydiolefin.
• the resultant material is then poured.
• the reaction of the carboxylic polydiolefin and the said agent entrains the resin constituting the binder.
• the composite explosive according to the invention is used in applications requiring the use of homogeneous explosives of easy operation.
• the present invention relates to a composite explosive having a rubbery binder especially suited for manufacture by pouring. This invention also relates to its manufacturing process.
• composite explosive is used to connote a mass of any shape having explosive properties and consisting essentially of a homogeneous dispersion of particles of some explosive substance in a possibly latticed binder which can also contain additives modifying the physical or detonatory characteristics.
• the first two are the conventional processes; and they employ pressures which can be very high (2000 bars).
• pressures which can be very high (2000 bars).
• the particles of explosive substance are imbedded in a binder and these particles are then subjected to high pressure at varying temperatures in order to obtain slabs (or cakes) having explosive properties.
• the compression processes use high pressures
• the extrusion processes make use of comparatively low pressure.
• the pouring processes operate without pressure.
• explosive substance such as: cyclonite, trinitrotoluene, pentaerythritol tetranitrate, tetryl, nitroguanidine, picric acid, nitrolactose, mannitol octanitrate and saccharose octanitrate;
• a polymerizable silicone is heated to form a gel having the required consistency, and the explosive substance is mixed into the polysilicone gel to produce the desired composition.
• These processes have the disadvantage of requiring reaction temperatures always higher than 100C and most frequently of the order of 125 to 150C which demand certain precautions in the manufacturing procedure.
• the detonation rates obtained with such explosive compositions are lower than 7000 meters/see, and the polymerizable silicones used are not very cheap raw materials.
• the pouring process employed does not allow the required precise shape and surface finish of the composite to be obtained.
• the present invention aims at remedying, in a simple manner, the above noted drawbacks. It comprehends composite explosives of varied shaped with a binder composition perfectly defined and at the same time compatible to the explosive substance and the pouring method of operation.
• the invention also provides a pouring process for manufacturing these varied forms of composite explosive with said binder composition.
• the composite explosive comprises particles of an explosive substance dispersed into a binder which is a rubbery material.
• the explosive constitutes at most 92 percent by weight of the composite and may be a nitro explosive or an organic nitrate such as octogen, hexogen, penthrite, tetryl or tolite.
• the binder is a resin based on at least one carboxylic polydiolefin.
• the composite may also include an oxidizer (up to 65 percent by weight of the total composite) such as a perchlorate.
• the composite may further include reducing metals, e.g., aluminum or magnesium; a plasticizer; an antioxidant and modifying adjuvants.
• the composite is produced by mixing the explosive substance and the binder with a chain extending or reticulating agent at about 20 to 95C. to form a mass which is poured to the desired shape.
• the composite explosive comprising particles of explosive material dispersed into a binder made up of a rubbery material is characterized by the fact that the binder is a resin having at least one carboxylic polydiolefin base and the proportion of explosive material is at most 92 percent by weight of the total weight of the composite explosive.
• the composite explosives produced according to the invention posses varied degrees of flexibility.
• the binder used is, in fact, a resin of which the composition and latticing rate are varied according to the required result, bearing in mind also the proportion of explosive material used.
• the binder is preferably the reaction product of at least one carboxylic polydiolefin, that is, one containing COOH groups (at least two to each molecule) with at least one chain extending agent and/or reticulating agent.
• the chain extending agent or reticulating agent contains for each molecule at least two functional groups capable of reacting with the COOH groups carried by the carboxylic polydiolefin which latter can, in these circumstances, be a prepolymer.
• the binder can also contain various secondary additives.
• the binder is a carboxylic polybutadiene-based latticed resin.
• the resin making up the binder is the reaction product of at least one carboxylic polybutadiene comprising at least two COOH groups to each molecule, with at least one chain extending agent and/or reciculating agent, such agent containing in each molecule at least two functional groups capable of reacting with the COOH groups borne by the carboxylic polybutadiene.
• the explosive substance is a very high explosive selected from among the nitro explosives and the organic nitrates, the proportion of explosive material advantageously being at least equal to 19 percent by weight of t the composite explosive.
• octogen homocyclonite or cyclotetramethylenetetranitramine of the formula: (CH N N hexogen cyclonite or cyclotrimethylenetrinitramine:
• the explosive compound further contains a powerful oxidizer, the said oxidizer forming at most 65 percent by weight ofthe composite explosive.
• This powerful oxidizer can be a perchlorate such as potassium perchlorate or ammonium perchlorate. These perchlorates can be used either alone or mixed. The use of these oxidizers offers the advantage of effecting a significant saving.
• the proportion of the binder according to the invention is greater than 8 percent by weight of the composite explosive and lies preferably between 8 and percent. It is thus possible to obtain extremely powerful composite high explosives.
• the composite explosive advantageously contains a finely divided metal of very high reducing power, the said finely divided metal being intended to produce a luminous effect, a blasting effect or an incendiary action.
• the finely divided metal is powdered aluminum or powdered magnesium.
• the proportion of said finely divided metal of very high reducing power is at most 65 percent by weight of the composite explosive.
• the binder composition according to the invention advantageously contains a plasticizer.
• the conventional polyolefin plasticizers such as:
• esters such as dioctyl azelate
• liquid polybutadienes and the like are used.
• the proportion of the plasticizer is at most 60 percent by weight of the binder.
• THe binder preferably contains an antioxidant.
• the conventional rubber antioxidants such as, for example: phenols and phosphites are used.
• Polygard nonyl phenyl phosphate
• MBP'5 which is 2,2'-bismethylene (4- methyl-6-tertiobutylphenol), and IONOL, which is 2,6-di-tertisobutyl-p-cresol
• the composite explosive according to the invention advantageously further contains adjuvants for modifying its physical and/or detonating properties (detonation velocity), for example minimum (Pb O,).
• adjuvants for modifying its physical and/or detonating properties for example minimum (Pb O,).
• the process for manufacturing the composite explosive according to the invention comprising particles of explosive material dispersed in a binder formed of rubbery material
• the process comprises mixing at least one carboxylic polydiolefin and at least one chain extending agent and/or reticulating agent with the particles of explosive substance, the said agent containing, in each molecule, at least two functional groups capable of reacting with the COOH groups carried by the said carboxylic polydiolefin, and'pouring the resultant mass.
• the reaction of the carboxylic polydiolefin and the said agent induces the formation of the latticed resin which forms the binder.
• the purpose of this process is to obtain directly, with the composition of the binder according to the invention, pieces of perfectly defined shape and in all sizes, having the desired surface finish and a density equal at all points to the theoretical density and not requiring subsequent machining.
• carboxylic polydiolefins whose molecular weights are in the range 1000 to 8000 and which contain between 0.2 and 3.0 gram-milliequivalents of -COOH are used. These carboxylic polydiolefins possess at least two COOH groups in each molecule and their viscosities are from to 800 poises at a temperature of 25C.
• the polydiolefin preferably possesses only two COOH groups per molecule attached to the ends of its main chain.
• a prepolymer of this kind, called carboxytelechelic, is used for obtaining products having the best elastic properties.
• the chain extending agent and/or reticulating agent is selected from the group formed by the polyepoxides. These compounds contain substituted or nonsubstituted epoxy groups.
• the characteristic feature of these epoxy groups is to open up by the addition of COOH groups without yielding light (small) molecules which have the tendency to consequently migrate or form gaseous occulsions within the composite explosive.
• the mechanical characteristics of the binder lattice can be considerably changed by altering the molecular bulk of the carboxylic polydiolefm as well as the functional state of the said agent (number of epoxy groups per molecule) and its molecular mass.
• the elasticity and pliancy of the binder lattice depends of course on the mean molecular weight of the chains bounded by the lattice nodes.
• Such polydiolefins, known, as previously mentioned, as carboxytelechelic prepolymers are therefore those tending to yield products having the best elastic properties.
• the pliancy of the composite explosive depends not only on the properties of the binder but also on the amount of explosive substance. It is thus possible to get lumps and slabs of composite explosive having various degrees of pliancy.
• the final properties of the rubbery lattice are determined by the latticing rate of the carboxylic polydiolefinbased resin. That rate can be changed by altering the relative proportions of bifunctional and multifunctional reticulating agents employed. The greater the mean number of reacting functional groups of the reticulating agent molecule, the closer the lattice and the stiffer the composite explosive obtained. Thus 0.8 to 1.3 epoxy groups is used for each COOH group. This figure represents the stoichiometric ratio of the epoxy groups of the polyepoxide relative to the COOH groups of the carboxylic polydiolefin. By changing the stoichiometric ratio around the value of unity, the latticing of the rubbery binder is altered and consequently its elasticity and pliancy characteristics.
• the latticing is accelerated by means of catalyzers such as organometallic compounds like the acetylacetonates (tautomeric acetylacetone salts), alkylmetallic derivatives, resorcylic acid salts, salts of lauric acid, of Z-ethyl hexanoic acid, of a naphthenic acid (essentially alkylcyclopentanc-acetic acid), the metals being iron, lead, tin or cobalt.
• organometallic compounds like the acetylacetonates (tautomeric acetylacetone salts), alkylmetallic derivatives, resorcylic acid salts, salts of lauric acid, of Z-ethyl hexanoic acid, of a naphthenic acid (essentially alkylcyclopentanc-acetic acid), the metals being iron, lead, tin or cobalt.
• a wetting agent is preferably incorporated, selected from following group of products:
• phosphatides such as lecithin
• Operation is preferably at temperatures between ambient termperature (about 20C. and C.
• ambient termperature about 20C. and C.
• the mix can advantageously be oscillated during pouring or after pouring. This operation, which can be done under vacuum, is for degassing the paste.
• the baking of the product at the end of the process is effected at a temperature allowing hardening within a suitable time (temperature less than 95C).
• the manufacturing process according to the invention therefore comprises in general the following operations:
• the baking (hardening) time is several days.
• the vacuum degassing of the mix with oscillation is a very important stage of the process since it contributes greatly to preventing gaseous occlusions in the composite explosive and allows the desired surface finish to be obtained, which is an indisputable advantage over the prior arts of pouring with composite explosives with rubbery binder.
• the purpose of the pouring process according to the invention is the direct procurement, with the binder composition made up of carboxylic polydiolefin-based resin, of pieces of perfectly defined shape and of all dimensions, having identical density at all points equal to 99.5 percent of the theoretical density as against the average 96 97 percent obtained by the former processes. These pieces do not split or fissure and they can be stuck directly onto the walls of the capacities into which they are poured, since they occupy the defined volume perfectly, whatever it may be, the polymerization contraction being negligible.
• the composite explosives so obtained are very homogeneous and not very porous, contrary to those obtained by the compression processes. Their mechanical properties are similar to those of loaded rubber. They are not fragile. They possess excellent resilience and a very good aging behavior. Their surface finish after pouring is greatly superior to the results obtained by conventional pouring processes which most freqntly require costly machining operations in order to obtain the precise form and finish required.
• the composite explosives of this invention can reach very high detonation velocities.
• the range of detonation velocities extends from 4000 to 8600 meters/sec.
• the following table displays the detonation velocities in terms of the relative proportions of explosive substance (octogen) and binder.
• carboxytelechelic polybutadienes of molecular weights 2000 and 4000 are used in these examples.
• liquid epoxy resins having 2.5 epoxy groups per kilogram
• Epon 812 which is a liquid epoxy resin having 6.5
• a kneader capable of working under vacuum. and the temperature of which can be adjusted between ambient temperature and 100C. is
• the product is vacuum oscillated until degassing is complete. Perfect degassing is thus secured contributing largely to avoiding the presence of gas occlusions in the composite explosive lump. By this means the surface finish required is obtained.
• the poured product is baked at the final kneading temperature; for this purpose the mold is placed in a zone kept at C.
• Binder F l5 Composition of Binder:
• the resulting lump is very flexible.
• Carhoxylic polyhutadiene 4000 1921 g Epoxy resin (25 epoxy groups per kg) 1.03 Stoichiometric ratio Dioctyl azelate 457 g Lead naphthenate 27 g lonol (2.6-di-tertisonutylp-cresol) 27 g Detonation velocity 7750 m/s.
• the resulting lump is very flexible.
• Example 6 all the constituents are also vacuum kneaded, but the work is done at a temperature of 45C.
• Example 2 the kneading is effected at 80C and first only the binder constituents are kneaded.
• Examples 1-15 the mix is oscillated before being poured; after that vacuum degassing with oscillation is obtained and the product is finally baked while working at a temperature lower in every case than C.
• a composite explosive as claimed in claim 4 wherein the perchlorate is potassium or ammonium perchlorate.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Dispersion Chemistry (AREA)
• Molecular Biology (AREA)
• Crystallography & Structural Chemistry (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Epoxy Resins (AREA)
• Casting Or Compression Moulding Of Plastics Or The Like (AREA)
• Heating, Cooling, Or Curing Plastics Or The Like In General (AREA)
• Processes Of Treating Macromolecular Substances (AREA)

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Citations (12)

• 1970
  • 1970-04-13 FR FR7013194A patent/FR2086881A5/fr not_active Expired
• 1971
  • 1971-01-01 AR AR234940A patent/AR203983A1/es active
  • 1971-03-22 CH CH416871A patent/CH532541A/fr not_active IP Right Cessation
  • 1971-04-05 ES ES389906A patent/ES389906A1/es not_active Expired
  • 1971-04-05 BE BE765268A patent/BE765268A/xx not_active IP Right Cessation
  • 1971-04-09 US US00132873A patent/US3839106A/en not_active Expired - Lifetime
  • 1971-04-13 BR BR2181/71A patent/BR7102181D0/pt unknown
  • 1971-04-13 DE DE2117854A patent/DE2117854C3/de not_active Expired
  • 1971-04-13 ZA ZA712298A patent/ZA712298B/xx unknown
  • 1971-04-13 JP JP2338271A patent/JPS5536637B1/ja active Pending
  • 1971-04-19 GB GB1297756D patent/GB1297756A/en not_active Expired

Patent Citations (12)

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