HIGH PEFORMANCE GAS GENERATING COMPOSITIONS

• US 20090255611A1
• Filed: 11/12/2008
• Published: 10/15/2009
• Est. Priority Date: 04/10/2008
• Status: Active Grant

• Current Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Original Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Inventors: Lund, Gary K., Bradford, Roger
• Granted Patent: US 8,815,029 B2
• Time in Patent Office: Days
• US Class Current: 149/45
• CPC Class Codes: C06B 21/0066 by granulation, e.g. flaking
• CPC Class Codes: C06D 5/06 by reaction of two or more solids

Abstract

Compositions and methods relating to gas generants used in inflatable restraint systems. The gas generant grains formed via spray drying techniques of the present disclosure provide superior performance, including high burn rates and high gas yields. Further, processing of the gas generant grain products can be streamlined. Such gas generants include by way of non-limiting example, guanidine nitrate, basic copper nitrate, and a secondary oxidizer, such as potassium perchlorate.

Claims

1. A method for making a gas generant comprising:

spray drying an aqueous mixture to produce a powder, wherein said aqueous mixture comprises guanidine nitrate, basic copper nitrate, and about 1% to about 30% by weight of a secondary oxidizer; and

pressing the powder to produce a gas generant grain.

2. The method of claim 1, wherein the aqueous mixture includes about 1% to about 15% by weight of said secondary oxidizer.

3. The method of claim 1, wherein the secondary oxidizer is a perchlorate salt.

4. The method of claim 1, wherein the secondary oxidizer comprises potassium perchlorate.

5. The method of claim 1, wherein the secondary oxidizer comprises a compound selected from the group consisting of:

ammonium perchlorate, potassium nitrate, strontium nitrate, sodium nitrate, and combinations thereof.

6. The method of claim 1, wherein the aqueous mixture further comprises at least one additive.

7. The method of claim 6, wherein the additive is a metal oxide.

8. The method of claim 7, wherein the metal oxide comprises a compound selected from the group consisting of:

cupric oxide, molybdenum oxide, iron oxide, bismuth oxide, and combinations thereof.

9. The method of claim 1, wherein the aqueous mixture further comprises less than or equal to about 5% by weight of a slag promoting agent.

10. The method of claim 9, wherein the slag promoting agent comprises a compound selected from the group consisting of:

silicon dioxide, zinc oxide, aluminum oxide, cerium oxide, and combinations thereof.

11. The method of claim 1, further comprising adding less than or equal to about 5% by weight of a slag promoting agent to the powder prior to the pressing.

12. The method of claim 11, wherein the slag promoting agent comprises a compound selected from the group consisting of:

silicon dioxide, zinc oxide, aluminum oxide, cerium oxide, and combinations thereof.

13. A gas generant grain made according to the method of claim 1, wherein the gas generant grain has a burning rate at least about 20% greater than a comparative burn rate of a comparative gas generant grain having substantially the same composition and produced by a process selected from the group consisting of:

roll compacting, milling, and/or mechanical mixing.

14. The method of claim 1, wherein the method further comprises prior to spray drying, forming a mixture comprising the guanidine nitrate, the basic copper nitrate, and the about 1% to about 30% by weight of said secondary oxidizer, by adding the guanidine nitrate to an aqueous medium;

adding the basic copper nitrate and secondary oxidizer to the aqueous medium; and

mixing the aqueous medium to form the aqueous mixture.

15. The method of claim 14, wherein the aqueous medium comprises water.

16. A gas generant made according to the method of claim 15.

17. The method of claim 1, wherein said spray drying of the aqueous mixture to produce the powder is performed using a single orifice fountain nozzle.

18. A gas generant made according to the method of claim 17.

19. The method of claim 1, wherein the pressing of the powder forms gas generant grains having a shape selected from tablets or cylinders.

20. The method of claim 1, further comprising adding a pressing agent to the powder prior to the pressing to form the gas generant grains.

21. The method of claim 20, wherein the pressing agent is selected from the group consisting of calcium stearate, magnesium stearate, graphite, molybdenum disulfide, tungsten disulfide, boron nitride, and combinations thereof.

22. A gas generant made according to the method of claim 1.

23. A gas generant grain comprising:

guanidine nitrate, basic copper nitrate, and about 1% to about 30% by weight of a secondary oxidizer comprising potassium perchlorate, wherein the gas generant grain has an average linear burn rate of greater than or equal to about 1.5 inches per second (about 38.1 mm per second) at a pressure of about 3,000 pounds per square inch (about 20,685 kPa).

24. A gas generant of claim 23 having a gas yield greater than or equal to about 3 moles/100 g of the gas generant.

25. A method for making a gas generant comprising:

spray drying an aqueous mixture via a single orifice fountain nozzle to produce a powder, wherein said aqueous mixture comprises guanidine nitrate, basic copper nitrate, and about 1% to about 30% by weight of a secondary oxidizer; and

pressing the powder to produce a gas generant grain having an average linear burn rate of greater than or equal to about 1.5 inches per second (about 38.1 mm per second) at a pressure of about 3,000 pounds per square inch (about 20,685 kPa).