Gas generating system

Abstract

The present invention generally relates to gas generant compositions for inflators of occupant restraint systems, for example. A gas generating composition 12 formed in accordance with the present invention includes a carboxyl alkyl cellulosic binder. A vehicle occupant protection system 180, and other gas generating systems, incorporate the compositions of the present invention.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional Application Ser. No. 60 / 557,473 filed on Mar. 30, 2004.TECHNICAL FIELD [0002] The present invention relates generally to gas generating systems, and to gas generant compositions employed in gas generator devices for automotive restraint systems, for example. BACKGROUND OF THE INVENTION [0003] The present invention relates to nontoxic gas generating compositions that upon combustion rapidly generate gases that are useful for inflating occupant safety restraints in motor vehicles and specifically, the invention relates to thermally stable nonazide gas generants having not only acceptable burn rates, but that also, upon combustion, exhibit a relatively high gas volume to solid particulate ratio at acceptable flame temperatures. [0004] The evolution from azide-based gas generants to nonazide gas generants is well-documented in the prior art. The advantages of nonazide gas generant comp...

AI Technical Summary

Benefits of technology

[0012] In sum, the present invention includes gas generant compositions that optimize the production of gas combustion products and minimize solid combustion products while retaining other design requirements such as reduced hygroscopicity, thermal stability, production safety, and reduced environmental impact. These and other advantages will be apparent upon a review of the detailed description.

Problems solved by technology

One of the disadvantages of known nonazide gas generant compositions is the amount and physical nature of the solid residues formed during combustion.

Further, gas generant compositions incorporating phase stabilized or pure ammonium nitrate sometimes exhibit poor thermal stability, and produce unacceptably high levels of toxic gases, CO and NOx for example, depending on the composition of the associated additives such as plasticizers and binders.

Accordingly, these types of binders result in compositions that often have poor thermal stability, and in particular with compositions containing preferred oxidizers such as phase stabilized ammonium nitrate.

Nevertheless, these compositions typically have poor oxygen balance thereby inhibiting the addition of energetic fuels.

Furthermore, the use of organic solvents when manufacturing compositions containing these binders complicates production from a safety standard due to the flammability and volatility of solvents such as ethyl acetate, propyl acetate, and butyl acetate.

Images