Composite pyrotechnic product with non-crosslinked binder and method for preparing same

Abstract

A composite pyrotechnic product, especially a propellant powder for barrel weapons, has a composition, expressed as weight percentages, that contains from 78% to 90% of organic energetic charges, and from 10% to 22% of a polymeric gum, chosen from polyurethane-polyester gums, polyurethane-polyether gums and mixtures thereof, the number-average molecular weight of which is greater than 20 000 g/mol and the Mooney viscosity of which is between 20 and 70 ML (5+4) at 100° C.

1 . A composite pyrotechnic product whose composition, expressed as weight percentages, contains:
 from 78% to 90% of organic energetic charges, and   from 10% to 22% of a polymeric gum, chosen from polyurethane-polyester gums, polyurethane-polyether gums and mixtures thereof, a number-average molecular weight of which is greater than 20 000 g/mol and a Mooney viscosity of which is between 20 and 70 ML (5+4) at 100° C.   
     
     
         2 . The composite pyrotechnic product as claimed in  claim 1 , wherein said organic energetic charges consist of hexogen, octogen, nitroguanidine, ethylene dinitramine, N-guanylurea dinitramide, 1,1-diamino-2,2-dinitroethylene, bis(triaminoguanidinium) 5,5′-azotetrazolate, dihydrazinium 5,5′-azotetrazolate, 5,5′-bis(tetrazolyl)hydrazine, bis(2,2-dinitropropyl)nitramine, a nitropyrazole, or a mixture of such charges. 
     
     
         3 . The composite pyrotechnic product as claimed in  claim 1 , wherein said organic energetic charges contain ethylene dinitramine charges. 
     
     
         4 . The composite pyrotechnic product as claimed in  claim 1 , wherein said polymeric gum has a number-average molecular weight of greater than 50 000 g/mol. 
     
     
         5 . The composite pyrotechnic product as claimed in  claim 1 , wherein said gum is a polyurethane-polyester gum or a polyurethane-polyether gum. 
     
     
         6 . The composite pyrotechnic product as claimed in  claim 1 , wherein the composition also contains at least one energetic or non-energetic plasticizer; said plasticizer representing from 2% to 8% by weight of the composition of said pyrotechnic product. 
     
     
         7 . The composite pyrotechnic product as claimed in  claim 6 , wherein said at least one plasticizer is an energetic plasticizer of nitrate and/or nitramine type. 
     
     
         8 . The composite pyrotechnic product as claimed in  claim 7 , wherein said at least one plasticizer is chosen from diethylene glycol dinitrate, triethylene glycol dinitrate, butanetriol trinitrate, trimethylolethane trinitrate, a mixture of 2,4-dinitro-2,4-diazapentane, 2,4-dinitro-2,4-diazahexane and 3,5-dinitro-3,5-diazaheptane, nitratoethylnitramines, and mixtures thereof. 
     
     
         9 . The composite pyrotechnic product as claimed in  claim 1 , wherein the composition also contains from 0.1% to 2% by weight of at least one additive. 
     
     
         10 . The composite pyrotechnic product as claimed in  claim 1 , wherein the composite pyrotechnic product consists of a propellant powder for barrel weapons. 
     
     
         11 . A process for preparing at least one composite pyrotechnic product as claimed in  claim 1 , the process comprising:
 a) providing the ingredients below:   
       organic energetic charges, 
       a polymeric gum, chosen from polyurethane-polyester gums, polyurethane-polyether gums and mixtures thereof, a number-average molecular weight of which is greater than 20 000 g/mol and a Mooney viscosity of which is between 20 and 70 ML (5+4) at 100° C.;
 b) mixing the ingredients in suitable proportions relative to the desired composition of the final product, to produce a pasty mixture; and 
 c) producing, from said pasty mixture, said at least one composite pyrotechnic product in a desired form. 
 
     
     
         12 . The process as claimed in  claim 11 , further comprising providing at least one energetic or non-energetic plasticizer and/or at least one additive, and mixing of said charges and gum with said at least one plasticizer and/or said at least one additive to obtain a pasty mixture. 
     
     
         13 . The process as claimed in  claim 11 , wherein said mixture is prepared with a twin-screw extruder or a two-roll mill. 
     
     
         14 . The process as claimed in  claim 11 , wherein said mixture is prepared at a temperature of between 60° C. and 120° C. 
     
     
         15 . The process as claimed in  claim 11 , wherein said at least one composite pyrotechnic product is obtained by spinning or calendering. 
     
     
         16 . The composite pyrotechnic product as claimed in  claim 1 , wherein the composition, expressed as weight percentages, contains from 80% to 86% of organic energetic charges. 
     
     
         17 . The composite pyrotechnic product as claimed in  claim 3 , wherein said organic energetic charges contain hexogen charges and ethylene dinitramine charges. 
     
     
         18 . The composite pyrotechnic product as claimed in  claim 4 , wherein said polymeric gum has a number-average molecular weight of greater than 75 000 g/mol. 
     
     
         19 . The composite pyrotechnic product as claimed in  claim 5 , wherein said gum is a polyurethane-polyester gum. 
     
     
         20 . The composite pyrotechnic product as claimed in  claim 6 , wherein the composition further contains an energetic plasticizer.