Gas generant manufacture

• US 6,436,211 B1
• Filed: 07/18/2000
• Issued: 08/20/2002
• Est. Priority Date: 07/18/2000
• Status: Expired due to Fees

• Current Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Original Assignee: Autoliv ASP Incorporated (Autoliv Incorporated)
• Inventors: Taylor, Robert D., Mendenhall, Ivan V., Smith, Robert G.
• Primary Examiner(s): Jordan, Charles T.
• Assistant Examiner(s): FELTON, AILEEN BAKER
• Application Number:
  US09/618,646
• Time in Patent Office: 763 Days
• Field of Search: 149/46, 149/109.6
• US Class Current: 149/109.6
• CPC Class Codes: C06B 31/00 Compositions containing an inorganic nitrogen-oxygen salt
• CPC Class Codes: C06D 5/06 by reaction of two or more solids

Abstract

A method of making a gas generant formulation which contains a transition metal diammine dinitrate is provided wherein a transition metal ammine carbonate is reacted with nitric acid in the presence of water to form a corresponding reaction mixture. A spray dryable precursor to the gas generant formulation is formed including at least a gas generating fuel and a sufficient quantity of water to render the precursor spray dryable. The precursor is subsequently spray dried to form a gas generant powder. The method may also include a relatively mild heat treatment of the dried material, either as a part of the spray drying or subsequent to such spray drying. A phase stabilized ammonium nitrate and a corresponding method of making the same wherein ammonium nitrate is stabilized through the presence of a stabilizing metal diammine dinitrate are also provided.

Claims

1. A method of making a gas generant formulation which contains a transition metal diammine dinitrate, the method comprising the steps of:

combining at least an ammine carbonate of at least one transition metal with nitric acid in the presence of water to form a corresponding reaction mixture;

forming a spray dryable precursor to the gas generant formulation, the precursor comprising the reaction mixture, a gas generant formulation fuel component and a sufficient quantity of water to render the precursor spray dryable; and

spray drying the precursor to form a gas generant powder containing a diammine dinitrate of the at least one transition metal.

2. The method of claim 1 additionally comprising the step of:

heat treating the gas generant powder.

3. The method of claim 2 wherein the heat treating step comprises heating the gas generant powder to a temperature no more than about 135°

C.

4. The method of claim 1 wherein:

the transition metal of the transition metal ammine carbonate is selected from the group consisting of copper, zinc and combinations thereof.

5. The method of claim 4 wherein transition metal ammine carbonate comprises copper diammine carbonate.

6. The method of claim 1 wherein the gas generating fuel component comprises an oxygenated nitrogen-containing organic compound.

7. The method of claim 6 wherein the gas generating fuel oxygenated nitrogen-containing organic compound is selected from the group consisting of guanidine nitrate, aminoguanidine nitrate, triaminoguanidine nitrate, nitroguanidine, nitrotriazalone and mixtures thereof.

8. The method of claim 1 wherein the gas generating fuel component comprises an organic compound with a high nitrogen content.

9. The method of claim 8 wherein the gas generating fuel organic compound with a high nitrogen content is selected from the group consisting of dicyandiamide, triazalone, tetrazoles, triazoles and mixtures thereof.

10. The method of claim 1 wherein the gas generating fuel component comprises a complex of at least one transition metal.

11. The method of claim 10 wherein the gas generating fuel transition metal complex is selected from the group consisting of transition metal complexes of tetrazoles and triazoles, transition metal nitrate complexes of nitrogen containing organic compounds and mixtures thereof.

12. The method of claim 1 wherein the precursor is formed to include the gas generating fuel component in an amount sufficient that the gas generating fuel comprises about 20 wt. % to about 70 wt. % of the transition metal diammine dinitrate-containing gas generant powder.

13. The method of claim 1 wherein the transition metal diammine dinitrate-containing gas generant powder comprises an oxidizer component constituting about 30 wt. % to about 60 wt. % of the formulation.

14. The method of claim 13 wherein the transition metal diammine dinitrate constitutes about 15 wt. % to about 100 wt. % of the oxidizer component.

15. The method of claim 14 wherein the precursor is formed to additionally include ammonium nitrate and wherein the oxidizer component additionally comprises ammonium nitrate.

16. The method of claim 1 wherein the precursor is formed to additionally include at least one performance additive and the transition metal diammine dinitrate-containing gas generant powder additionally includes the at least one performance additive.

17. The method of claim 16 wherein the at least one performance additive is selected from the group of aluminum oxide, silicon dioxide and combinations thereof.

18. The method of claim 1 wherein the precursor is formed to contain between about 30 wt. % and about 35 wt. % water.

19. A method of making a gas generant formulation which contains a gas generant fuel component and an oxidizer component comprising at least one transition metal diammine dinitrate selected from the group consisting of copper diammine dinitrate, zinc diammine dinitrate and combinations thereof, the method comprising the steps of:

combining an ammine carbonate of at least one transition metal elected from the group consisting of copper, zinc and mixtures thereof with nitric acid in the presence of water and in relative amounts to form a corresponding reaction mixture containing nitric acid in no more than a stoichiometric amount for reaction of the ammine carbonate and the nitric acid to form a corresponding diammine dinitrate;

forming a precursor to a spray dryable gas generant formulation, the precursor comprising the aqueous reaction mixture, additional gas generant formulation components including at least one gas generating fuel material and at least one performance additive selected from the group of aluminum oxide, silicon dioxide and combinations thereof, and a sufficient quantity of water to form a spray dryable gas generant formulation precursor slurry; and

spray drying the gas generant formulation precursor slurry to form a gas generant powder; and

heating the gas generant powder to a temperature in the range of about 125°

C. to about 135°

C. to form a gas generant formulation which contains a gas generant fuel component and an oxidizer component comprising a diammine dinitrate of the at least one transition metal.

20. The method of claim 19 wherein the at least one gas generating fuel material is selected from the group consisting of oxygenated nitrogen-containing organic compounds, organic compounds with a high nitrogen content, complexes of at least one transition metal and combinations thereof.

21. The method of claim 19 wherein the precursor is formed to include the gas generating fuel component in an amount sufficient that the gas generating fuel comprises about 20 wt. % to about 70 wt. % of the gas generant formulation.

22. The method of claim 19 wherein the gas generant formulation comprises an oxidizer component constituting about 30 wt. % to about 60 wt. % of the formulation.

23. The method of claim 22 wherein the transition metal diammine dinitrate constitutes about 15 wt. % to about 100 wt. % of the oxidizer component.

24. The method of claim 19 wherein the precursor is formed to additionally include ammonium nitrate and wherein the oxidizer component additionally comprises ammonium nitrate.

25. The method of claim 19 wherein the precursor is formed to contain between about 30 wt. % and about 35 wt. % water.

26. A method of making a gas generant formulation which contains a gas generant fuel component and an oxidizer component comprising at least one transition metal diammine dinitrate selected from the group consisting of copper diammine dinitrate, zinc diammine dinitrate and combinations thereof, the method comprising the steps of:

combining at least one ammine carbonate of a transition metal elected from the group consisting of copper, zinc and mixtures thereof with a quantity of nitric acid in the presence of water and in relative amounts to form a corresponding reaction mixture wherein no free nitric acid remains after reaction of the at least one ammine carbonate with the nitric acid;

forming a precursor to a spray dryable gas generant formulation, the precursor comprising the reaction mixture, additional gas generant formulation components including a sufficient amount of at least one gas generating fuel material selected from the group consisting of oxygenated nitrogen-containing organic compounds, organic compounds with a high nitrogen content, complexes of at least one transition metal and combinations thereof whereby about 20 wt. % to about 70 wt. % of the gas generant formulation constitutes such fuel material, at least one performance additive selected from the group of aluminum oxide, silicon dioxide and combinations thereof, and a sufficient quantity of water to form a spray dryable gas generant formulation precursor slurry containing between about 30 wt. % to about 35 wt. % water;

spray drying the gas generant formulation precursor slurry to form a gas generant powder; and

heating the gas generant powder to a temperature in the range of about 125°

C. to about 135°

C. to form a heat treated gas generant powder comprising about 30 wt. % to about 60 wt. % of an oxidizer component, wherein the transition metal diammine dinitrate constitutes about 15 wt. % to about 100 wt. % of the oxidizer component.

27. The method of claim 26 wherein the oxidizer component additionally comprises ammonium nitrate and wherein the precursor is formed to include ammonium nitrate.

28. A method of making a phase stabilized ammonium nitrate, the method comprising:

drying and heat treating an aqueous slurry containing ammonium nitrate and a combination of at least one transition metal ammine carbonate and nitric acid, the nitric acid present in more than a stoichiometric amount relative to the at least one transition metal ammine carbonate for formation of the a corresponding transition metal diammine dinitrate, to form a phase stabilized ammonium nitrate.

29. The method of claim 28 wherein the drying comprises spray drying.

30. The method of claim 28 wherein the phase stabilized ammonium nitrate contains at least about 10 wt. % of a diammine dinitrate of the at least one transition metal.

31. The method of claim 30 wherein the phase stabilized ammonium nitrate contains at least about 15 wt. % of a diammine dinitrate of the at least one transition metal.

32. A phase stabilized ammonium nitrate made by drying and heat treating an aqueous slurry containing ammonium nitrate and a combination of at least one transition metal ammine carbonate and nitric acid, present in no more than a stoichiometric amount relative to the at least one transition metal ammine carbonate for formation of a corresponding transition metal diammine dinitrate, to form a phase stabilized ammonium nitrate.