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NITROCHEMIE'S Polymer-Bonded Propellant Approach~From Seat Belt Pretensioners Towards Airbag Applications
Technical Paper
2006-31-0033
Sector:
Event:
Airbag 2006
Language:
English
Abstract
Nitrochemie is a supplier of a family of special nitrocellulose-based propellants for modern car occupant safety systems. Through the consequent pursuit of research and development efforts in partnership with our customers, Nitrochemie is in the position to offer propelling solutions, which are collectively fulfilling the USCAR requirements on thermal stability as well as combustion gas composition. The two polymer-bonded propellant types PB-40 and PB-70 are suitable alternatives to single-base propellants in new seat belt pretensioner applications. After 408 h at 107°C the observed interior ballistic changes in a micro gas generator are found to be within the specified limits of the USCAR. The observed weight losses of 1.6 - 2.2% after 408 h at 107°øC result in a peak pressure reduction of less than 5%. For loading weights of up to 800 mg it was found, that after deploying a micro gas generator in a 60 l tank all effluent levels lie below the applicable USCAR limits. Nitrochemie is currently extending the polymer-bonded approach from seat belt pretensioner applications towards airbag deployment. By adjusting the geometry of the polymer-bonded propellants the desired vivacity for airbag deployment can be achieved; the maximum-peak pressure is reached between 20 - 60 ms. As more energetic material is needed in propellants for airbag applications the requirements on thermal stability and gas effluents after combustion are raised compared to those for seat belt pretensioner. Slight changes in the binder composition and form function resulted in prototype propellants with weight losses below 1% after 408 h at 107°C, acceptable gas effluent levels after combustion and good ignitability. Thus, the adaptability in geometry and composition of Nitrochemie's polymer-bonded propellant approach allows a wide range of pressure time curves reflecting the different requirements of activators, seat belt pretensioners, side and passenger airbags.