Pyrotechnic composition for use as advanced ignition means

Abstract

A pyrotechnic composition, in particular for use in safety devices for motor vehicles, has an auto-ignition temperature between 140 and 180 degrees C., and comprises at least 3-nitro-1,2,4-triazol-5-one (NTO) in a proportion of 20 to 60% by weight. The NTO is stabilized by at least one of the following measures: (a) the NTO has an average grain size of 200 to 600 □m; and (b) the composition comprises an oil in an effective quantity for stabilizing the NTO. The pyrotechnic composition is adapted for use in a safety device, in particular in a safety device in motor vehicles.

1 . A pyrotechnic composition having an auto-ignition temperature between about 140 and 180 degrees C., said pyrotechnic composition comprising 3-nitro-1,2,4-triazol-5-on (NTO) in a proportion of 20 to 60% by weight, wherein said NTO is stabilized, said stabilized NTO comprising at least one of: 
 (a) said NTO having an average grain size of between about 200 to 600 □m; and    (b) an oil admixed to said composition in an effective quantity for reducing a reactivity of said NTO.    
   
   
       2 . The pyrotechnic composition according to  claim 1 , wherein said stabilized NTO comprises an oil admixed to said composition, said composition comprising said oil in a proportion of additively 0.1 to 3% by weight.  
   
   
       3 . The pyrotechnic composition according to  claim 1 , wherein said oil is selected from the group consisting of natural and synthetic mineral oils, plant and animal oils and also essential oils and mixtures thereof.  
   
   
       4 . The pyrotechnic composition according to  claim 3 , wherein said mineral oil is one of a functionalized and non-functionalized silicone oil.  
   
   
       5 . The pyrotechnic composition according to  claim 1 , wherein said composition additionally comprises a guanidine compound.  
   
   
       6 . The pyrotechnic composition according to  claim 5 , wherein said guanidine compound is selected from the group consisting of guanidine nitrate, aminoguanidine nitrate, diaminoguanidine nitrate, triaminoguanidine nitrate, nitroguanidine and mixtures thereof.  
   
   
       7 . The pyrotechnic composition according to  claim 5 , wherein said composition comprises said stabilized NTO in a proportion of 20 to 50% by weight, said guanidine compound in a proportion of 30 to 50% by weight and from 0 to 50% by weight of an inorganic oxidizer selected from the group consisting of alkali metal nitrates and alkaline earth metal nitrates.  
   
   
       8 . The pyrotechnic composition according to  claim 7 , wherein said composition comprises said stabilized NTO in a proportion of 30 to 50% by weight, guanidine nitrate in a proportion of 30 to 50% by weight and sodium nitrate in a proportion of 0 to 40% by weight.  
   
   
       9 . The pyrotechnic composition of  claim 7 , wherein said stabilized NTO comprises said oil admixed to said composition in an amount of additively between about 0.1 and 3% by weight.  
   
   
       10 . The pyrotechnic composition of  claim 9 , wherein said stabilized NTO has an average grain size of between about 200 μm and 600 μm.  
   
   
       11 . The pyrotechnic composition according to  claim 1 , wherein said composition further comprises conventional processing aids in a proportion of additively 0 to 2% by weight.  
   
   
       12 . A gas generator for use in a safety device, in particular in a vehicle occupant restraint system, comprising a pyrotechnic propellant, an igniter for activating said pyrotechnic propellant, and an auto-ignition means associated with at least one of said pyrotechnic propellant and said igniter, said auto-ignition means consisting of a pyrotechnic composition having an auto-ignition temperature of between about 140 and 180 degrees C., said pyrotechnic composition comprising at least 3-nitro-1,2,4-triazol-5-on (NTO) in a proportion of about 20 to 60% by weight, wherein said NTO is stabilized, said stabilized NTO comprising at least one of: 
 (a) said NTO, having an average grain size of about 200 to 600 □m; and    (b) an oil admixed to said pyrotechnic composition in an effective quantity for reducing a reactivity of said NTO.    
   
   
       13 . The gas generator according to  claim 12 , wherein said pyrotechnic propellant and said auto-ignition means are present in a mixture which is stable with regard to storage.  
   
   
       14 . A method of activating a gas generator of an occupant restraint system in vehicles under vehicle fire conditions, said gas generator comprising a pyrotechnic propellant, an igniter for activating said pyrotechnic propellant and an auto-ignition means associated with at least one of said pyrotechnic propellant or said igniter, said method comprising the step of self-igniting said auto-ignition means at a temperature between about 140 to 180° C. thereby triggering a reaction of said pyrotechnic propellant, wherein said auto-ignition means consists essentially of a pyrotechnic composition comprising at least 3-nitro-1,2,4-triazol-5-on (NTO) in a proportion of 20 to 60% by weight, wherein said NTO is stabilized, said stabilized NTO comprising at least one of: 
 (a) said NTO, having an average grain size of about 200 to 600 □m; and    (b) an oil admixed to said pyrotechnic composition in an effective quantity for reducing a reactivity of said NTO.