Thin composite explosive products and preparation thereof

Abstract

A composite explosive product, wherein its composition expressed as percentages by weight includes 85% to 92% of organic energetic charges; the organic energetic charges a) 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 D90 less than 15 μm and a value for D50 less than or equal to 5 μm; and 7% to 12% of 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 and of Mooney viscosity lying in the range 20 to 70 ML (5+4) at 100° C.; and wherein the composite explosive product has a thickness lying in the range 0.4 mm to 5 mm.

1 . A composite explosive product, wherein:
 its composition expressed as percentages by weight comprises:
 +85% to 92% of organic energetic charges; said organic energetic charges a) 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 μm and a value for D 50  less than or equal to 5 μm; and 
 +7% to 12% of 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 and of Mooney viscosity lying in the range 20 to 70 ML (5+4) at 100° C.; and 
   wherein the composite explosive product presents a thickness lying in the range 0.4 mm to 5 mm.   
     
     
         2 . The composite explosive product according to  claim 1 , wherein said energetic charges are selected from charges of hexogen (RDX), of hexanitrohexaazaisowurtzitane (CL20), and mixtures thereof, 
     
     
         3 . The composite explosive product according to  claim 1 , wherein said polymer gum is a polyurethane-polyester gum or a polyurethane-polyether gum. 
     
     
         4 . The composite explosive product according to  claim 1 , wherein said polymer gum presents a number average molecular weight greater than 35,000 g/mol. 
     
     
         5 . The composite explosive product according to  claim 1 , wherein its composition further includes at least one plasticizer, selected from energetic plasticizers, non-energetic plasticizers, and mixtures thereof; said at least one plasticizer generally being present at a content of 1% to 4% by weight. 
     
     
         6 . The composite explosive product according to  claim 1 , wherein its composition further includes at least one additive; said at least one additive generally being present at a content of 0.1% to 1% by weight. 
     
     
         7 . The composite explosive product according to  claim 1 , wherein the composite explosive product is in the form of a sheet or of an element cut out from a sheet without cutting out holes passing through the thickness of said sheet, or in the form of an element cut out from a sheet with through hole(s) being cut out in the thickness of said sheet. 
     
     
         8 . The composite explosive product according to  claim 7 , wherein the composite explosive product consists in an explosive sheet, an explosive bar with a V-groove, or in a miniaturized array for multipoint initiation of explosive charges. 
     
     
         9 . The composite explosive product according to  claim 1 , wherein the composite explosive product it consists in a miniaturized array for multipoint initiation of explosive charges suitable for use on a plane surface or on a curved surface of said explosive charges. 
     
     
         10 . A method for obtaining a composite explosive product according to  claim 1 , the method comprising:
 incorporating said charges in said gum raised to a temperature of at least 50° C.; said incorporating being performed in a cylinder mill; and   calendaring the resulting loaded sheet in a cylinder mill.   
     
     
         11 . The method according to  claim 10 , the method further comprising:
 cutting up the calendared loaded sheet.   
     
     
         12 . The composite explosive product according to  claim 1 , wherein its composition comprises 88% to 90% of organic energetic charges. 
     
     
         13 . The composite explosive product according to  claim 1 , wherein its composition comprises 8% to 10% of the polymer gum. 
     
     
         14 . The composite explosive product according to  claim 1 , wherein the composite explosive product presents a thickness lying in in the range 1 mm to 2 mm. 
     
     
         15 . The composite explosive product according to  claim 3 , wherein said polymer gum is a polyurethane-polyester gum. 
     
     
         16 . The composite explosive product according to  claim 4 , wherein said polymer gum presents a number average molecular weight greater than 75,000 g/mol. 
     
     
         17 . The composite explosive product according to  claim 5 , wherein said at least one plasticizer is present at a content of 2% by 3% by weight. 
     
     
         18 . The method according to  claim 10 , wherein the temperature is in the range 60° C. to 80° C. 
     
     
         19 . The method according to  claim 11 , wherein the cutting up is performed with waterjet(s), with two parallel blades, or with a cutter die.