Thermally stable nonazide automotive airbag propellants

• US 6,306,232 B1
• Filed: 05/05/1997
• Issued: 10/23/2001
• Est. Priority Date: 07/29/1996
• Status: Expired due to Term

• Current Assignee: Automotive Systems Laboratory, Incorporated (Ningbo Junsheng Investment Group Co., Ltd.)
• Original Assignee: Automotive Systems Laboratory, Incorporated (Ningbo Junsheng Investment Group Co., Ltd.)
• Inventors: Burns, Sean P., Khandhadia, Paresh S.
• Primary Examiner(s): Carone, Michael J.
• Assistant Examiner(s): Palo, Francis T.
• Application Number:
  US08/851,503
• Time in Patent Office: 1,632 Days
• Field of Search: 149/47, 149/36, 149/46
• US Class Current: 149/22
• CPC Class Codes: C06D 5/06 by reaction of two or more solids

Abstract

Thermally stable gas generant compositions incorporate a combination of nitroguanidine, one or more nonazide high-nitrogen fuels, and phase-stabilized ammonium nitrate or a similar nonmetallic oxidizer that, upon combustion, result in a greater yield of gaseous products per mass unit of gas generant, a reduced yield of solid combustion products, and acceptable burn rates, thermal stability, and ballistic properties. These compositions are especially suitable for inflating air bags in passenger-restraint devices.

Claims

1. A gas generant composition consisting of a hydrated or anhydrous mixture of:

nitroguanidine and at least one nonazide high-nitrogen fuel selected from the group consisting of guanidines, tetrazoles, triazoles, salts of tetrazoles, and salts of triazoles; and

phase stabilized ammonium nitrate as an oxidizer,

wherein said composition has a melting point of at least 115°

C., the ammonium nitrate is phase stabilized by coprecipitating with potassium nitrate, said nitroguanidine comprises 1%-26% by weight of said mixture;

said at least one nonazide high-nitrogen fuel comprises 4%-40% by weight of said mixture, said nitroguanidine in combination with said at least one nonazide high nitrogen fuel comprises 15%-60% by weight of said mixture, and, said phase stabilized ammonium nitrate comprises 40%-85% by weight of said mixture.

2. A gas generant composition as claimed in claim 1 further comprising:

a burn rate modifier selected from the group consisting of alkali and alkaline earth metal nitrates and nitrites, dicyandiamide, alkali and alkaline earth metal salts of dicyandiamide, alkali and alkaline earth borohydrides, and mixtures thereof, wherein said bum rate modifier comprises not more than 10% by weight of said mixture.

3. A gas generant composition as claimed in claim 1 further comprising:

a combination slag former and coolant selected from the group consisting of clay, silica, glass, alumina, and mixtures thereof.

4. The composition of claim 1 wherein said at least one nonazide high nitrogen fuel is selected from the group consisting of 5-nitrotetrazole, 5,5′

-bitetrazole, nitroaminotriazole, and 3-nitro-1,2,4 triazole-5-one.

5. A gas generant composition consisting of a hydrated or anhydrous mixture of:

nitroguanidine and at least one nonazide high-nitrogen fuel selected from the group consisting of monoguanidinium salt of 5,5′

-Bis-1H-tetrazole, diguanidinium salt of 5,5′

-Bis-1H-tetrazole, monoaminoguanidinium salt of 5,5′

-Bis-1H-tetrazole, diaminoguanidinium salt of 5,5′

-Bis-1H-tetrazole, monohydrazinium salt of 5,5′

-Bis-1H-tetrazole, dihydrazinium salt of 5,5′

-Bis-1H-tetrazole, monoammonium salt of 5,5′

-bis-1H-tetrazole, diammonium salt of 5,5′

-bis-1H-tetrazole, mono-3-amino-1,2,4-triazolium salt of 5,5′

-bis-1H-tetrazole, di-3-amino-1,2,4-triazolium salt of 5,5′

-bis-1H-tetrazole, diguanidinium-5,5′

-azotetrazolate, monoammonium salt of 3-nitro-1,2,4-triazole, monoguanidinium salt of 3-nitro-1,2,4-triazole, diammonium salt of dinitrobitriazole, diguanidinium salt of dinitrobitriazole, and monoammonium salt of 3,5-dinitro-1,2,4-triazole; and

phase stabilized ammonium nitrate as an oxidizer,

wherein the ammonium nitrate is phase stabilized by coprecipitating with potassium nitrate, said nitroguanidine comprises 1%-26% by weight of said mixture, said at least one nonazide high-nitrogen fuel comprises 4%-40% by weight of said mixture, said nitroguanidine in combination with said at least one nonazide high nitrogen fuel comprises 15%-60% by weight of said mixture, and, said phase stabilized ammonium nitrate comprises 40%-85% by weight of said mixture.

6. A gas generant composition consisting of a hydrated or anhydrous mixture of:

nitroguanidine and at least one nonazide high-nitrogen fuel selected from the group consisting of nonmetal salts of triazoles substituted at the 1-, 3-, and 5-positions, and nonmetal salts of tetrazoles substituted at the 1- and 5-positions, said salts substituted at each position with a nitrogen-containing group; and

phase stabilized ammonium nitrate as an oxidizer,

wherein the ammonium nitrate is phase stabilized by coprecipitating with potassium nitrate, said nitroguanidine comprises 1%-26% by weight of said mixtures said at least one nonazide high-nitrogen fuel comprises 4%-40% by weight of said mixture, said nitroguanidine in combination with said at least one nonazide high nitrogen fuel comprises 15%-60% by weight of said mixture, and, said phase stabilized ammonium nitrate comprises 40-85% by weight of said mixture.

7. A gas generant composition consisting of a hydrated or anhydrous mixture of:

nitroguanidine and at least one nonazide high-nitrogen fuel selected from the group consisting of 1-, 3-, 5- substituted nonmetal salts of triazoles, and 1-, 5- substituted nonmetal salts of tetrazoles, said salts substituted at each position with a nitrogen-containing compound; and

phase stabilized ammonium nitrate as an oxidizer,

wherein the ammonium nitrate is phase stabilized by coprecipitating with potassium nitrate, said nitroguanidine comprises 1%-26% by weight of said mixture;

said at least one nonazide high-nitrogen fuel comprises 4%-40% by weight of said mixture, said nitroguanidine in combination with said at least one nonazide high nitrogen fuel comprises 15%-60% by weight of said mixture, said phase stabilized ammonium nitrate comprises 40-85% by weight of said mixture.

8. A gas generant composition consisting of a hydrated or anhydrous mixture of:

nitroguanidine and at least one nonazide high-nitrogen fuel selected from the group consisting of guanidines, tetrazoles, triazoles, salts of tetrazoles, and salts of triazoles;

phase stabilized ammonium nitrate as an oxidizer, a burn rate modifier selected from the group consisting of alkali, alkaline earth, and transitional metal salts of tetrazole and triazole, triaminoguanidine nitrate, dicyandiamide, alkali and alkaline earth metal salts of dicyandiamide;

alkali and alkaline earth borohydrides, and mixtures thereof; and

a coolant selected from the group consisting of clay, silica, glass, and alumina, and mixtures thereof;

wherein said composition has a melting point of at least 115°

C., the ammonium nitrate is phase stabilized by coprecipitating with potassium nitrate, said nitroguanidine comprises 1%-26% by weight of said mixture;

said at least one nonazide high-nitrogen fuel comprises 4%-40% by weight of said mixture, said nitroguanidine in combination with said at least one nonazide high nitrogen fuel comprises 15%-60% by weight of said mixture, said phase stabilized ammonium nitrate comprises 40-85% by weight of said mixture, said burn rate modifier comprises 0-10% by weight of said mixture, and said coolant comprises 0-10% by weight of said mixture.

9. A gas generant composition consisting of a hydrated or anhydrous mixture of:

nitroguanidine and at least one nonazide high-nitrogen fuel selected from the group consisting of monoguanidinium salt of 5,5′

-Bis-1H-tetrazole, diguanidinium salt of 5,5′

-Bis-1-tetrazole, monoaminoguanidinium salt of 5,5′

-Bis-1H-tetrazole, diaminoguanidinium salt of 5,5′

-Bis-1H-tetrazole, monohydrazinium salt of 5,5′

-Bis-1H-tetrazole, dihydrazinium salt of 5,5′

-Bis-1-tetrazole, monoammonium salt of 5,5′

-bis-1H-tetrazole, diammonium salt of 5,5′

-bis-1H-tetrazole, mono-3-amino-1,2,4-triazolium salt of 5,5′

-bis-1H-tetrazole, di-3-arnino-1,2,4-triazolium salt of 5,5′

-bis-1H-tetrazole, diguanidinium-5,5′

-azotetrazolate, monoammonium salt of 3-nitro-1,2,4-triazole, monoguanidinium salt of 3-nitro-1,2,4-triazole, diammonium salt of dinitrobitriazole, diguanidinium salt of dinitrobitriazole, and monoammonium salt of 3,5-dinitro- 1,2,4-triazole;

phase stabilized ammonium nitrate as an oxidizer,

a burn rate modifier selected from the group consisting of alkali, alkaline earth, and transitional metal salts of tetrazole and triazole, triaminoguanidine nitrate, dicyandiamide, alkali and alkaline earth metal salts of dicyandiamide;

alkali and alkaline earth borohydrides, and mixtures thereof; and

a coolant selected from the group consisting of clay, silica, glass, and alumina, and mixtures thereof;

wherein the ammonium nitrate is phase stabilized by coprecipitating with potassium nitrate, said nitroguanidine comprises 1%-26% by weight of said mixture, said at least one nonazide high-nitrogen fuel comprises 4%-40% by weight of said mixture, said nitroguanidine in combination with said at least one nonazide high nitrogen fuel comprises 15%-60% by weight of said mixture, said phase stabilized ammonium nitrate comprises 40%-85% by weight of said mixture, said burn rate modifier comprises 0-10% by weight of said mixture, and said coolant comprises 0-10% by weight of said mixture.

10. A gas generant composition consisting of a hydrated or anhydrous mixture of:

nitroguanidine and at least one nonazide high-nitrogen fuel selected from the group consisting of nonmetal salts of triazoles substituted at the 1-, 3-, and 5-positions, and nonmetal salts of tetrazoles substituted at the 1- and 5-positions, said salts substituted at each position with a nitrogen-containing group;

phase stabilized ammonium nitrate as an oxidizer,

a bum rate modifier selected from the group consisting of alkali, alkaline earth, and transitional metal salts of tetrazole and triazole, triaminoguanidine nitrate, dicyandiamide, alkali and alkaline earth metal salts of dicyandiamide;

alkali and alkaline earth borohydrides, and mixtures thereof; and

a coolant selected from the group consisting of clay, silica, glass, and alumina, and mixtures thereof;

wherein the ammonium nitrate is phase stabilized by coprecipitating with potassium nitrate, said nitroguanidine comprises 1%-26% by weight of said mixture, said at least one nonazide high-nitrogen fuel comprises 4%-40% by weight of said mixture, said nitroguanidine in combination with said at least one nonazide high nitrogen fuel comprises 15%-60% by weight of said mixture, said phase stabilized ammonium nitrate comprises 40-85% by weight of said mixture, said burn rate modifier comprises 0-10% by weight of said mixture, and said coolant comprises 0-10% by weight of said mixture.

11. A gas generant composition consisting of a hydrated or anhydrous mixture of:

nitroguanidine and at least one nonazide high-nitrogen fuel selected from the group consisting of 1-, 3-, 5-substituted nonmetal salts of triazoles, and 1-, 5-substituted nonmetal salts of tetrazoles, said salts substituted at each position with a nitrogen-containing compound;

phase stabilized ammonium nitrate as an oxidizer,

a burn rate modifier selected from the group consisting of alkali, alkaline earth, and transitional metal salts of tetrazole and triazole, triaminoguanidine nitrate, dicyandiamide, alkali and alkaline earth metal salts of dicyandiamide;

alkali and alkaline earth borohydrides, and mixtures thereof; and

a coolant selected from the group consisting of clay, silica, glass, and alumina, and mixtures thereof;

wherein the ammonium nitrate is phase stabilized by coprecipitating with potassium nitrate, said nitroguanidine comprises 1%-26% by weight of said mixture;

said at least one nonazide high-nitrogen fuel comprises 4%-40% by weight of said mixture, said nitroguanidine in combination with said at least one nonazide high nitrogen fuel comprises 15%-60% by weight of said mixture, said phase stabilized ammonium nitrate comprises 40-85% by weight of said mixture, said burn rate modifier comprises 0-10% by weight of said mixture, and said coolant comprises 0-10% by weight of said mixture.

12. A gas generant composition consisting of a hydrated or anhydrous mixture of:

nitroguanidine,

diammonium salt of 5,5′

-bis-1H-tetrazole,

phase stabilized ammonium nitrate as an oxidizer,

wherein the ammonium nitrate is phase stabilized by coprecipitating with potassium nitrate, said nitroguanidine comprises 1%-26% by weight of said mixtures said diammonium salt of 5,5′

-bis-1H-tetrazole comprises 4%40% by weight of said mixture, said nitroguanidine in combination with said diammonium salt of 5,5′

-bis-1H-tetrazole comprises 15%-60% by weight of said mixture, and, said phase stabilized ammonium nitrate comprises 40-85% by weight of said mixture.