Classifications

• • 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
• • 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
  • 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
  • C06B25/00—Compositions containing a nitrated organic compound
  • C06B25/34—Compositions containing a nitrated organic compound the compound being a nitrated acyclic, alicyclic or heterocyclic amine
• • 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
  • C06B45/12—Compositions or products which are defined by structure or arrangement of component of product having contiguous layers or zones

Definitions

• the present invention relates to thin composite explosive products (of well-controlled small thickness) that are shapeable (i.e. deformable, by the action of temperature, with conservation of shape) and that are of high performance.
• They contain a large content of energetic charges in a binder of specific nature. They consist in particular in sheets or in products obtained by cutting up such sheets, such as miniature arrays for multipoint initiation of explosive charges, e.g. explosive warheads.
• the present invention also provides a method of preparing such composite explosive products. Said method is particularly easy to perform: at temperatures that are entirely compatible with the sensitivity of the energetic charges present, without using solvent, and including operations of only one type.
• This critical detonation dimension is determined from samples of decreasing size (e.g. cylindrical stepped bars of decreasing section), with detonation being initiated at the end of the sample having the largest dimension (the end of the bar presenting the greatest section).
• a small critical detonation dimension is advantageously less than or equal to 5 millimeters (mm), or indeed less than or equal to 1.5 mm, or even less than or equal to 1 mm.
• Patent U.S. Pat. No. 3,354,010 describes explosive products in the form of flexible sheets (typically having a thickness of 6.3 mm), of composition that contains organic energetic charges of the hexogen (HMX) and/or octogen (RDX) type in a binder (nitrocellulose) that is plasticized (tributyl acetylcitrate).
• HMX hexogen
• RDX octogen
• Those products are obtained a priori by using two methods, both of which are relatively complex to perform: 1) obtaining a mixture comprising a solvent, evaporating said solvent, obtaining granules, and then shaping by extrusion, molding, or rolling; or 2) using hot mixing to obtain a paste comprising ethanol and rolling said paste.
• Elastomers (gums, “uncured” rubbers (i.e. “green” rubbers)) of the polyurethane-polyester type (i.e. of polyurethane nature with flexible segments of polyester type) and/or of polyurethane-polyether type (i.e. of polyurethane nature with flexible segments of polyether type), have also been made commercially available for several years, in particular under the trademark Urepan® from the supplier RheinChemie, and under the trademark Millathane® by the supplier TSE Industries. The present invention provides an original opening for this type of elastomer.
• the inventors have the merit of proposing such a product that is constituted essentially by specific energetic charges (said “highly” energetic charges, i.e. “sensitive charges” being present in the form of fine grains (micrometer size) at a “maximum” content ( ⁇ 85% by weight)) together with a binder of a novel type, said binder making it possible to obtain said product by a method that is particularly easy to perform (not requiring the use of a solvent, the viscosity of the binder not requiring high temperature (dangerous, given the sensitivity of the charges), requiring operations of only one type, in a single type of device (cylinder (roller) mill(s)), or indeed in a single device (cylinder (roller) mill) (see below)). It was not obvious to obtain explosive products having a high content of fine grain size charges, and even less obvious to obtain such products by a method that is easy to perform.
• the present invention thus provides novel composite explosive products.
• Said products which present a critical detonation dimension that is small given their specific composition (composition containing a high content of charges, charges that are “highly” energetic, i.e. “sensitive”, and of fine grain size) thus combine a thickness that is small (although naturally greater than or equal to the critical detonation dimension) to said specific composition.
• the composite explosive products of the invention present:
• the composite explosive products of the invention thus include a large content of charges, organic charges that are “strongly” energetic (“sensitive”) and of fine grain size in a binder of a novel type.
• the composite explosive products of the invention contain 85% to 92%, advantageously 88% to 90% (percentages by weight) of specific organic energetic charges.
• the charges in question are charges that are “strongly” energetic (“sensitive”). They are octogen (HMX) charges, hexogen (RDX) charges, hexanitrohexaazaisowurtzitane (CL20) charges, penthrite (PEEN) charges, or a mixture of such charges.
• HMX octogen
• RDX hexogen
• CL20 hexanitrohexaazaisowurtzitane
• PEEN penthrite
• they are hexogen (RDX) charges, hexanitrohexaazaisowurtzitane (CL20) charges, or a mixture of these two types of charge (the most energetic).
• the charges in question are not present in the form of large and small crystals, they are present in the form of small crystals only. They are charges (fines) that present a grain size distribution with a value for D 90 that is less than 15 ⁇ m and a value for D 50 that is less than or equal to 5 ⁇ m (thus specifying the notions of charges that are “fines” and crystals that are “small”).
• the value for D 10 is not specified insofar as it is not critical in any way. It can be understood that the finer the charges (i.e. the lower the value for D 10 (e.g. a value of 100 nanometers (nm) or even smaller)), the more advantageous the products in question.
• This grain size data (D 90 , D 50 (and D 10 )) is measured using photon correlation spectroscopy-diffusion light scattering (PCS-DLS) grain size measurement using a procedure defined in standard NF 11-666. They correspond respectively to the diameter at which the cumulative volume percentage (of particles of charge) is equal to 90%, 50% (median diameter) (and 10%).
• PCS-DLS photon correlation spectroscopy-diffusion light scattering
• Such fine charges are generally obtained by grinding “large” crystals.
• the person skilled in the art knows numerous grinding methods that are suitable for the sensitivity of the charges in question. In entirely non-limiting manner, mention may be made of the possibility of using Sweco® grinders.
• the Applicant has also described in French patent application FR 14/00669, published under the U.S. Pat. No. 3,018,807 (on Sep. 25, 2015), an original grinding method for obtaining CL20 charges having submicrometer monomodal grain size. That method comprises continuously grinding a charge of CL20 crystals of grain size greater than one micrometer (D 50 >1 ⁇ m), in suspension in a liquid; said grinding being performed, with cooling, by multiple passes of the suspension through a horizontal axis flow attrition grinder with stirred grinding media.
• D 50 >1 ⁇ m micrometer
• organic energetic charges (present in quantities, of nature, and of grain size, as specified above) are thus to be found in the composition of composite explosive products of the invention within a binder that is original.
• Said binder is a polymer gum:
• the products of the invention can be shaped insofar as said gum is shapeable. When raised to an appropriate temperature, it can be shaped and subsequently conserve the shape it has been given. This shape can be modified only by a further action of temperature.
• the inventors have the merit of identifying (selecting) this type of binder, which is entirely suitable for the purposes of the invention.
• Other types of binder have been tested and have not given satisfactory results (as to the possibility of obtaining the mixture, of working at low temperature, and/or as to the properties of the final product of small thickness).
• the binder of products of the invention generally consists in a polyurethane-polyester gum or a polyurethane-polyether gum, however it is possible to use mixtures of at least two gums (at least two polyurethane-polyester gums, at least two polyurethane-polyether gums, or at least one polyurethane-polyester gum and at least one polyurethane-polyether gum; such mixtures of gums (gums in the meaning of the invention) constituting a gum in the meaning of the invention) presenting the required properties (set out above)).
• Said binder advantageously consists in a polyurethane-polyester gum.
• composition of pyrotechnic composite products of the invention may further include at least one plasticizer selected from energetic plasticizers, non-energetic plasticizers, and mixtures thereof; it may further include generally up to 4% by weight of at least one such plasticizer.
• at least one plasticizer at least one energetic plasticizer, at least one non-energetic plasticizer, or at least one energetic plasticizer and at least one non-energetic plasticizer
• Said at least one plasticizer is thus selected from non-energetic plasticizers (e.g. dioctyl azelate (DOZ), di-2-ethylhexyl sebacate (DOS), di-n-octyl phthalate (DOP), triacetin, and mixtures thereof), energetic plasticizers (advantageously of nitrate or nitramine type, e.g.
• DEGDN diethylene glycol dinitrate
• TAGDN triethylene glycol dinitrate
• BTTN butanetriol trinitrate
• TMETN trimethylolethane trinitrate
• 2,4-dinitro-2,4-diaza-pentane 2,4-dinitro-2,4-diaza-hexane
• 3,5-dinitro-3,5-diaza-heptane and most particularly DNDA 5,7
• nitrato ethyl nitramines and in particular methyl-2-nitratomethyl nitramine (methylNENA) and ethyl-2-nitratoethyl nitramine (ethylNENA)
• methylNENA methyl-2-nitratomethyl nitramine
• ethylNENA ethyl-2-nitratoethyl nitramine
• the composition of composite pyrotechnic products of the invention includes, as a plasticizer, triethylene glycol dinitrate (TEGDN).
• TAGDN triethylene glycol dinitrate
• composition of composite explosive products of the invention thus contains:
• organic energetic charges being selected from charges of octogen (HMX), hexogen (RDX), hexanitrohexaazaisowurtzitane (CL20), penthrite (PETN), and mixtures thereof, and b) presenting a grain size distribution with a value for D 90 less than 15 ⁇ m and a value for D 50 less than or equal to 5 ⁇ m; and
• a polymer gum selected from polyurethane-polyester gums, polyurethane-polyether gums, and mixtures thereof, of number average molecular weight greater than 20,000 g/mol (advantageously greater than 35,000 g/mol, most advantageously greater than 75,000 g/mol) and of Mooney viscosity lying in the range 20 to 70 ML (5+4) at 100° C.;
• a plasticizer selected from energetic plasticizers, non-energetic plasticizers, and mixtures thereof;
• composition generally consists in the specified ingredients.
• a product of the invention presents a (single) thickness (e), a thickness (e) that is uniform and constant (well-controlled): 0.4 mm ⁇ e ⁇ 5 mm, advantageously 1 mm ⁇ e ⁇ 2 mm. Most advantageously, they present a thickness: e ⁇ 1.5 mm.
• the composite pyrotechnic products of the invention may be of any type of shape, and in particular they may be:
• the cutting in question is conventional cutting, performed using conventional mechanical means (advantageously cutting by waterjet(s), with two parallel blades, or with a cutter die).
• composite pyrotechnic products of the invention may consist in particular:
• an explosive sheet usable as demolition material, as cutting material, as metal-forming material, (see point a) above);
• V-groove in an explosive bar with a V-groove (usable as an element forming part of a detonating cutter cord, said V-groove being aimed to be covered with a metal coating or with a coating loaded with metal particles) (see point b) above); or
• the channels of the miniaturized array naturally present a section that is at least equal to the critical detonation dimension of the composition in question. They may present changes of direction with large angles, up to 90° (given the small values of said critical dimensions). They are generally square or rectangular in section.
• Such arrays of the invention are particularly advantageous. Their shapeability (inherent to the nature of the binder present in their composition and to their small thickness) enable them to be used both on surfaces that are plane (it is possible to initiate a charge of cylindrical shape in conventional manner using such an array positioned on one of the bases of the charge) and on surfaces that are curved (such unconventional positioning can be particularly advantageous for increasing the speed of shrapnel in one direction).
• the invention provides a method of preparing (obtaining) composite pyrotechnic products of the invention, as described above.
• said method is based on using at least one cylinder mill (or roller mill).
• it comprises incorporating charges in the binder in a cylinder mill. More precisely, it comprises:
• plasticizer or additive involved is also incorporated in the gum in the cylinder mill.
• a cylinder mill (or roller mill) is a device that is itself known.
• the present invention relies on selecting the binder in association with selecting the method, this double selection making it possible not only to obtain products of the invention (products loaded with a large content of fine sensitive charges) (where the feasibility of said method was not clear in advance), but to do so under working conditions that are simple.
• the mixture is made up in the cylinder mill in conventional manner, with the cylinders rotating in opposite directions at different speeds.
• the gum When the gum is present in the form of granules, it is initially worked coarsely in a roll mill in order to obtain a thin strip (thickness 1 mm to a few millimeters).
• Said gum is generally initially introduced into the cylinder mill while its cylinders are raised to a temperature (T) of at least 50° C. (less than 120° C., generally less than 100° C.), advantageously in the range 60° C. to 80° C. (60° C. ⁇ T ⁇ 80° C.), e.g. 70° C. Thereafter, the charges and any other ingredient(s) (optional plasticizer(s) and additive(s)) are introduced, either separately or in a mixture.
• a charges+ingredient(s) mixture is prepared beforehand when such at least one ingredient is involved, and it is the mixture that is introduced into the mill. Charges may advantageously be introduced in a plurality of sequences after adjusting the spacing of the cylinders.
• the coating that builds up around the faster-turning cylinder can be recovered (cut away with a cutter), folded, and reintroduced between the cylinders (in order to make the distribution of the charges more uniform), in the usual manner for this method.
• said sheet is calendared in a cylinder mill (the cylinders of said cylinder mill then rotate in the same direction, at the same speed, with the spacing between them being adjusted to the desired thickness value, or to a smaller value since there are two phenomena that might occur: the material might force the cylinders apart, and the products might relax after being rolled).
• the successive steps of the method of the invention obtaining the mixture in the form of a product of small thickness (sheet) and calendaring—are performed most advantageously with the same cylinder mill.
• mixing, rolling, and calendaring are all performed; thus, at a single station, it is possible to obtain a sheet type product of the invention directly (the desired product or the product suitable for use in preparing other desired products of the invention, in particular by being cut).
• the method of the invention may thus further include cutting the calendared and loaded sheet, advantageously by waterjet(s), using two parallel blades, or a cutter die.
• Cut-out elements are thus obtained as specified above. Said cut-out elements can also be worked, as mentioned above.
• the cutting of the sheets can be facilitated by heating said sheets beforehand to a temperature in the range 40° C. to 50° C.
• Urepan® 643 G sold by the supplier RheinChemie (product of polyaddition of diphenyl-methane diisocyanate and a polyester). It presents the following characteristics:
• Urepan® 600 sold by the supplier RheinChemie (product of polyaddition of toluene diisocyanate and a polyester). It presents the following characteristics:
• Step a) of the method pasty mixtures were obtained using a cylinder mill, in known manner.
• the gum in question was initially introduced between the rollers and raised to a temperature of 70° C. That softened it. Thereafter, a mixture of charges plus plasticizer, previously prepared in a container, was added. In Example 8, only the charges were added. Once all of the charges were incorporated in the gum, the milling was continued for about 15 minutes (min). At this stage (see Example 1), it was possible to incorporate small quantities (0.3% in said Example 1) of candellila wax very progressively in order to lubricate the loaded gum and the cylinders. After incorporating the wax, milling was continued for five minutes. By then, one of the cylinders was coated.
• Step b) of the method calendaring was performed to adjust and/or make more uniform the thickness of the sheets that were obtained. Said sheets were passed between the two cylinders of the same cylinder mill, set at the desired spacing, and rotating in the same direction, at the same speed. This time, the sheets did not wind around a cylinder. Calendaring was performed. Once the calendaring stage was terminated, the product obtained in the form of a sheet was uniform and presented constant thickness (of 2 mm, 1.5 mm, or 1 mm).
• Step c) of the method the sheet was cut into channels of various sections using specific tooling, made up essentially of two parallel blades of spacing guaranteed by washers of calibrated thicknesses. The sheets were cut up after being raised to a temperature of 45° C.
• compositions of Examples 1, 2, and 3 containing RDX charges are particularly advantageous in that they present a critical detonation section that is less than or equal to 1 mm 2 .
• compositions of Examples 6 and 7, containing CL20 charges present critical detonation sections that are larger (the critical detonation section of the composition of Example 6 is greater than 1.5 mm 2 and the critical detonation section of the composition of Example 7 lies in the range 1 mm 2 to 1.5 mm 2 ) than the critical detonation sections of Examples 1, 2, and 3 containing RDX charges.
• the increase in the charge content leads logically to a decrease in the critical detonation section (the charge content of the composition of Example 6 is 86% whereas the charge content of the composition of Example 7 is 87%).
• Binder hydroxyl-terminated polybutadiene (HTPB) (sold by the supplier Cray Valley under the name R45HT) of number average molecular weight 2800 g/mol (binder conventionally used in the context of composite energetic products).
• HTPB hydroxyl-terminated polybutadiene
• a1 Very viscous pastes were obtained by milling using said binder (20% by weight) and RDX charges (80% by weight), referenced M3c from Eurenco, presenting a grain size distribution with a D 10 value of 1 ⁇ m, a D 50 value of 4 ⁇ m, and a D 90 value of 9 ⁇ m (see above). They were cast, with difficulty, (at small thickness) in molds made of polymethyl methacrylate (PMMA) (stepped test pieces) and they were tested within said molds (any unmolding would involve degradations) in order to evaluate their critical sections. The critical sections were about 3 mm 2 .
• a curing agent diisocyanate
• Binder lauryl methacrylate.
• This binder which is very liquid, made it possible to incorporate a high content of small charges therein. It must nevertheless necessarily be cured.
• Pastes containing 14% by weight of lauryl methacrylate (+curing agent: diisocyanate) and 86% by weight of CL20 (of grain size distribution presenting a D 10 value of 0.5 ⁇ m, a D 50 value of 4.7 ⁇ m, and a D 90 value of 12.2 ⁇ m (see above)) were prepared. They were cast in molds in order to be in the form of sheets of small thicknesses. Said sheets were subjected to heat treatment to cure the lauryl methacrylate. The shrinkage that occurred during curing meant that it was not possible to control the thickness of the cured sheets. Specifically, in order to obtain sheets of controlled small thickness (e.g. 2 mm), it was initially necessary to proceed as follows: obtain sheets of substantial thickness (e.g. 10 mm) by molding, subject them to heat treatment, and then machine them to said controlled small thickness.

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• 2014
  • 2014-11-21 FR FR1402626A patent/FR3028852B1/fr not_active Expired - Fee Related
• 2015
  • 2015-11-20 CA CA2968255A patent/CA2968255A1/fr not_active Abandoned
  • 2015-11-20 EP EP15804911.4A patent/EP3221283B1/de active Active
  • 2015-11-20 US US15/527,932 patent/US20180346393A1/en not_active Abandoned
  • 2015-11-20 WO PCT/FR2015/053158 patent/WO2016079453A1/fr active Application Filing
• 2017
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