Gas-generating pyrotechnic compound and production process

Abstract

The present invention provides pyrotechnic gas generator compounds and a method of obtaining them. Said compounds have a composition which comprises: an oxidizing charge which comprises at least one inorganic perchlorate and which does not comprise a chlorine scavenger; and a crosslinked, oxygen-containing hydrocarbon binder obtained by crosslinking an elastomer in the presence of at least one crosslinking agent and at least one oxygen-containing plasticizer for said elastomer; said elastomer having a molecular weight of more than 200 000 and being preferably selected from polyesters and polyacrylates; said at least one oxygen-containing plasticizer being composed of a plasticizer of which the molecular weight is greater than 350 g/mol and the oxygen balance equal to or greater than −230 %, of a mixture of such plasticizers with one another or of a mixture of at least one such plasticizer with at least one other oxygen-containing plasticizer. Said compounds can be obtained continuously by extrusion.

1 . A pyrotechnic gas generator compound whose composition comprises:
 an oxidizing charge which comprises at least one inorganic perchlorate; and   a crosslinked, oxygen-containing hydrocarbon binder obtained by crosslinking an elastomer in the presence of at least one crosslinking agent and at least one oxygen-containing plasticizer for said elastomer; said elastomer having a molecular weight of more than 200 000 and being preferably selected from polyesters and polyacrylates;   
       wherein:
 said oxidizing charge does not contain a chlorine scavenger; and 
 said at least one oxygen-containing plasticizer is composed of a plasticizer of which the molecular weight is greater than 350 g/mol and the oxygen balance equal to or greater than −230%, of a mixture of such plasticizers with one another or of a mixture of at least one such plasticizer with at least one other oxygen-containing plasticizer. 
 
     
     
         2 . The pyrotechnic compound of  claim 1 , wherein said plasticizer or plasticizers of which the molecular weight is greater than 350 g/mol and the oxygen balance equal to or greater than −230% are selected from diesters having ether functions. 
     
     
         3 . The compound of  claim 1 , wherein said at least one oxygen-containing plasticizer is selected from:
 dibutoxyethoxyethyl adipate,   dibutoxyethoxyethoxyethyl adipate,   dibutoxyethoxyethoxyethyl glutarate,   dibutoxyethoxyethoxyethyl phthalate,   bis(ethylene glycol monobutyl ether) adipate,   bis(ethylene glycol monobutyl ether) phthalate   mixtures of said diesters with one another, and   mixtures of at least one of said diesters with dioctyl adipate and/or dioctyl azelate.   
     
     
         4 . The compound of  claim 1 , wherein said oxidizing charge represents 64% to 94% by weight, advantageously 72% to 82% by weight, of the total weight of said compound. 
     
     
         5 . The compound of  claim 1 , wherein said oxidizing charge comprises ammonium perchlorate; in that advantageously said oxidizing charge is composed of ammonium perchlorate. 
     
     
         6 . The compound of
   claim 1 , wherein said crosslinked, oxygen-containing hydrocarbon binder represents 6% to 20% by weight, advantageously 8% to 16% by weight, of the total weight of said compound.   
     
     
         7 . The compound of  claim 1 , wherein said at least one elastomer and said at least one crosslinking agent represent from 3% to 10% by weight, advantageously from 4% to 8% by weight, of the total weight of said compound; and/or, advantageously, and,
 said at least one plasticizer represents from 3% to 10% by weight, advantageously from 4% to 8% by weight, of the total weight of said compound.   
     
     
         8 . The compound of  claim 1 , wherein its composition further comprises at least one organic nitro compound of which the oxygen balance is greater than −30%; in that its composition advantageously further comprises at least one organic nitro compound selected from nitrogenous nitrates and dinitramides. 
     
     
         9 . The compound of  claim 1 , wherein its composition further comprises at least one ballistic catalyst, advantageously selected from copper oxide, iron oxide, manganese oxide, and cobalt oxide. 
     
     
         10 . The compound of  claim 1 , wherein its composition further comprises at least one wetting agent selected from organosilanes and titanates, advantageously selected from vinyltris(2-methoxyethoxy)si lane, tris(3-trimethoxysilylpropyl) isocyanurate, γ-glycidyloxypropyltrimethoxysilane, diethoxydiacetoxysilane, diacetoxydiethoxysilane, and dibutoxyethoxymethylsilane. 
     
     
         11 . The compound of  claim 1 , wherein its composition comprises, expressed in percentages by weight:
 64% to 94%, advantageously 72% to 82%, of an oxidizing charge;   6% to 20%, advantageously 8% to 16%, of at least one crosslinked, oxygen-containing hydrocarbon binder;   0% to 10%, advantageously 3% to 8%, of at least one organic nitro compound of which the oxygen balance is greater than −30%;   0% to 6%, advantageously from 1% to 2%, of at least one ballistic catalyst; and   0% to 4%, advantageously 0.2% to 3%, of at least one wetting agent.   
     
     
         12 . The compound of  claim 1 , of monolithic type, which is solid or mono- or multi-perforated. 
     
     
         13 . A method of obtaining a compound of  claim 1 , wherein it comprises:
 continuously implementing a solventless mixing of said oxidizing charge, said elastomer, said at least one crosslinking agent, and said at least one plasticizer and also, optionally, said at least one organic nitro compound of which the oxygen balance is greater than −30% and/or said at least one ballistic catalyst and/or said at least one wetting agent, and an extrusion of the paste resulting from said mixing;   heat-treating said extruded paste to carry out the crosslinking of said elastomer.   
     
     
         14 . The method of  claim 13 , wherein said mixing and said extruding are implemented in a twin-screw mixer-extruder. 
     
     
         15 . The method of  claim 13 , wherein it comprises cutting the extruded paste into charges and heat-treating said charges.