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Gas generant compositionsGas generant compositions description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070277915, Gas generant compositions. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS-REFERENCE TO RELATED APPLICATIONS [0001]This application claims the benefit of U.S. Provisional Application Ser. No. 60/810,006 filed on May 31, 2006. TECHNICAL FIELD [0002]The present invention relates generally to gas generating systems, and to gas generating compositions employed in gas generator devices for automotive restraint systems, for example. BACKGROUND OF THE INVENTION [0003]The present invention relates to gas generant compositions that upon combustion produce a relatively smaller amount of solids and a relatively abundant amount of gas. It is an ongoing challenge to reduce the amount of solids and increase the amount of gas thereby decreasing the filtration requirements for an inflator. As a result, the filter may be either reduced in size or eliminated altogether thereby reducing the weight and/or size of the inflator. Additionally, reduction of combustion solids provides relatively greater amounts of gaseous products per gram or unit of gas generating composition. Accordingly, less gas generant is required when greater mols of gas are produced per gram of gas generant. The result is typically a smaller and less expensive inflator due to reduced manufacturing complexity. [0004]Yet another concern is that the compositions must exhibit burn rates that are satisfactory with regard to use in vehicle occupant protection systems. In particular, compositions containing phase stabilized ammonium nitrate may exhibit relatively lower burn rates requiring various measures to improve the burn rate. Accordingly, the development of energetic fuels is one ongoing research emphasis whereby the less aggressive burn characteristics of preferred oxidizers such as phase stabilized ammonium nitrate are accommodated and compensated. SUMMARY OF THE INVENTION [0005]The above-referenced concerns are resolved by novel gas generant compositions. A fuel constituent or compound is selected from transitional metal salts of 5-aminotetrazole including copper 5-aminotetrazole, nickel 5-aminotetrazole, zinc 5-aminotetrazole. Phase stabilized ammonium nitrate, stabilized in a known manner, is included as a primary oxidizer. [0006]An optional second fuel may be selected from tetrazoles and salts thereof, triazoles and salts thereof, azoles and salts thereof, guanidines and salts thereof, guanidine derivatives, amides, and mixtures thereof. An optional secondary oxidizer is selected from metal and nonmetal nitrates, nitrites, chlorates, perchlorates, oxides, other known oxidizers, and mixtures thereof. [0007]In further accordance with the present invention, a gas generator or gas generating system, and a vehicle occupant protection system incorporating the gas generant composition are also included. BRIEF DESCRIPTION OF THE DRAWINGS [0008]FIG. 1 is a cross-sectional side view showing the general structure of an inflator in accordance with the present invention. [0009]FIG. 2 is a schematic representation of an exemplary vehicle occupant restraint system containing a gas generant composition in accordance with the present invention. DETAILED DESCRIPTION OF THE INVENTION [0010]The present invention provides a gas generant system that includes at least one of the following: improved ability to prevent formation of a low-melting point eutectic, improved effluent quality, enhanced thermal stability, and/or improved burn rates when employing phase-stabilized ammonium nitrate as an oxidizer. Accordingly, gas generant compositions containing a transitional metal salt of 5-aminotetrazole and phase-stabilized ammonium nitrate (PSAN) are provided. The PSAN may for example, contain about 10% potassium nitrate coprecipitated within ammonium nitrate in a known manner. This combination results in gas generant compositions that exhibit a burn rate of 0.8 ips at 1500 psi or 1.5 ips at 5500 psi, and/or, provide thermal stability at 107 C for over 400 hours. [0011]In one embodiment, the copper salt of 5-aminotetrazole is provided as a fuel at about 70% by weight of the total gas generant composition. Phase-stabilized ammonium nitrate is provided at about 30% by weight of the total gas generant composition. In general, a fuel component containing a transitional metal salt of 5-aminotetrazole, including nickel, magnesium, zinc, or copper complexes/salts of 5-AT, may be provided at about 5-70 wt. % of the composition. An oxidizing component, including phase-stabilized ammonium nitrate, may be provided at about 5-70 wt. %. [0012]Secondary fuels include tetrazoles such as 5-aminotetrazole; metal salts of azoles such as potassium 5-aminotetrazole; nonmetal salts of azoles such as diammonium salt of 5,5'-bis-1H-tetrazole: nitrate salts of azoles such as 5-aminotetrazole; nitramine derivatives of azoles such as 5-aminotetrazole; metal salts of nitramine derivatives of azoles such as dipotassium 5-aminotetrazole; metal salts of nitramine derivatives of azoles such as dipotassium 5-aminotetrazole; nonmetal salts of nitramine derivatives of azoles such as monoammonium 5-aminotetrazole and; guanidines such as dicyandiamide; salts of guanidines such as guanidine nitrate; nitro derivatives of guanidines such as nitroguanidine; azoamides such as azodicarbonamide; nitrate salts of azoamides such as azodicarbonamidine dinitrate; and mixtures thereof. If desired, these fuels are provided at about 0.1-25 wt. percent of the total composition. When combined with the transitional metal complex of 5-aminotetrazole, are provided at about 5-70 wt. percent of the total composition. A preferred amount of fuel is about 30 wt. percent of the total composition. [0013]Secondary oxidizers include metal nitrates such as strontium nitrate and potassium nitrate; metal nitrite salts such as potassium nitrite; metal oxides such as iron oxide; non-metal or metal perchlorates or chlorates such as ammonium perchlorate and potassium perchlorate; and other oxidizers recognized by those of ordinary skill. If desired, these oxidizers are provided at about 0.1-25 wt. percent of the total composition. [0014]Processing aids such as fumed silica, boron nitride, and graphite may also be employed. Accordingly, the gas generant may be safely compressed into tablets, or slugged and then granulated. The gas generant may also include binders such as cellulose derivatives, cellulose acetate, and cellulose acetate butyrate, and carboxymethylcellulose, salts of carboxymethylcellulose; silicone; polyalkene carbonates such as polypropylene carbonate and polyethylene carbonate. The processing aid and/or binder is generally provided at about 0-15 wt %, and more preferably at about 0-5 wt %. [0015]Slag formers may also be provided and are selected from silicon compounds such as elemental silicone; silicon dioxide; silicones such as polydimethylsiloxane; silicates such as potassium silicates; natural minerals such as talc, mica, and clay, and other known slag formers or coolants. The slag former is typically provided at about 0-10 wt %, and more preferably at about 0-5 wt %. [0016]The compositions of the present invention are formed from constituents as provided by known suppliers such as the Nippon Carbide, Aldrich, or Fisher Chemical companies. The compositions may be provided in granulated form and dry-mixed and compacted in a known manner, or otherwise mixed as known in the art. The compositions may be employed in gas generators typically found in airbag devices or occupant protection systems, or in safety belt devices, or in gas generating systems such as a vehicle occupant protection system, all manufactured as known in the art, or as appreciated by one of ordinary skill. EXAMPLES [0017]The following examples illustrate the benefits of compositions of the present invention: Continue reading about Gas generant compositions... Full patent description for Gas generant compositions Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Gas generant compositions patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Gas generant compositions or other areas of interest. ### Previous Patent Application: Metal matrix composite energetic structures Next Patent Application: Method and system for manufacture and delivery of an emulsion explosive Industry Class: Explosive and thermic compositions or charges ### FreshPatents.com Support Thank you for viewing the Gas generant compositions patent info. IP-related news and info Results in 0.18196 seconds Other interesting Feshpatents.com categories: Computers: Graphics , I/O , Processors , Dyn. Storage , Static Storage , Printers 174 |
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