Inflator for an air bag

• US 20030051630A1
• Filed: 08/07/2002
• Published: 03/20/2003
• Est. Priority Date: 08/10/2001
• Status: Active Grant

• Current Assignee: Daicel Chemical Industries Limited (Daicel Corporation)
• Original Assignee: Daicel Chemical Industries Limited (Daicel Corporation)
• Inventors: Wu, Jianzhou, Katsuda, Nobuyuki, Yabuta, Mikio
• Granted Patent: US 6,854,395 B2
• Time in Patent Office: Days
• US Class Current: 102/531
• CPC Class Codes: B60R 2021/2633 with a plurality of inflation levels
• CPC Class Codes: B60R 2021/2648 comprising a plurality of combustion chambers or sub-chambers
• CPC Class Codes: B60R 21/2644 using only solid reacting substances, e.g. pellets, powder
• CPC Class Codes: C06D 5/06 by reaction of two or more solids

Abstract

The present invention provides an inflator capable of realizing downsizing and weight reduction.

An inflator for an air bag comprising, in a housing having a gas discharging port, a combustion chamber accommodating a molded article of a gas generating composition which is burnt to generate a gas and an ignition means to ignite the molded article of a gas generating composition, wherein the molded article of the gas generating composition contains a metal component and meets the requirement (A) the (theoretical) combustion flame temperature of the molded article of the gas generating composition is 2000° C. or less, and part or the whole of the metal or metal oxide after combustion of the molded article of the gas generating composition has a melting point not lower than the combustion flame temperature, and the requirement (B) bulk combustion residues remain in the combustion chamber at the time of combustion of the molded article of the gas generating composition.

Claims

1. An inflator for an air bag comprising, in a housing having a gas discharging port, a combustion chamber accommodating a molded article of a gas generating composition which is burnt to generate a gas and an ignition means to ignite the molded article of a gas generating composition, wherein the molded article of the gas generating composition contains a metal component and meets the following requirements (A) and (B):

(A) the (theoretical) combustion flame temperature of the molded article of the gas generating composition is 2000°

C. or less, and part or the whole of the metal or metal oxide after combustion of the molded article of the gas generating composition has a melting point not lower than the combustion flame temperature; and

(B) bulk combustion residues remain in the combustion chamber at the time of combustion of the molded article of the gas generating composition.

3. The inflator for an air bag according to claim 1 or 2, wherein the combustion flame temperature in the requirement (A) is 1800°

C. or less.

4. The inflator for an air bag according to claim 1 or 2, wherein the combustion flame temperature in the requirement (A) is 1600°

C. or less.

5. The inflator for an air bag according to claim 1 or 2, wherein the combustion flame temperature in the requirement (A) is 1400°

C. or less.

6. The inflator for an air bag according to claim 1 or 2, wherein the combustion flame temperature in the requirement (A) is 1200°

C. or less.

7. The inflator for an air bag according to any one of claims 1 to 6, wherein the lower limit of the combustion flame temperature in the requirement (A) is 800°

C.

8. The inflator for an air bag according to any one of claims 1 to 6, wherein the lower limit of the combustion flame temperature in the requirement (A) is 900°

C.

9. The inflator for an air bag according to any one of claims 1 to 8, wherein, in the requirement (A), in the metal or metal oxide after combustion of the molded article of the gas generating composition, those having a higher melting point than the combustion flame temperature of the molded article of the gas generating composition is not less than 2% by weight.

10. The inflator for an air bag according to any one of claims 1 to 8, wherein, in the requirement (A), in the metal or metal oxide after combustion of the molded article of the gas generating composition, those having a higher melting point than the combustion flame temperature of the molded article of the gas generating composition is not less than 5% by weight.

11. The inflator for an air bag according to any one of claims 1 to 8, wherein, in the requirement (A), in the metal or metal oxide after combustion of the molded article of the gas generating composition, those having a higher melting point than the combustion flame temperature of the molded article of the gas generating composition is not less than 50% by weight.

12. The inflator for an air bag according to any one of claims 1 to 8, wherein, in the requirement (A), in the metal or metal oxide after combustion of the molded article of the gas generating composition, those having a higher melting point than the combustion flame temperature of the molded article of the gas generating composition is not less than 90% by weight.

13. The inflator for an air bag according to any one of claims 1 to 12, wherein, in the requirement (A), the metal or metal oxide after combustion of the molded article of the gas generating composition is copper, silica, alumina, cobalt oxide, ironoxides (Fe₂O₃, FeO and Fe₃O₄), strontium oxide, barium oxide, calcium oxide, magnesium oxide, titanium oxide, tungsten oxide, or a combination of an alkaline earth metal oxide and silica.

14. The inflator for an air bag according to any one of claims 1 to 13, wherein, in the requirement (B), the shape of the molded article of the gas generating composition is approximate to the shape of bulk combustion residues.

15. The inflator for an air bag according to any one of claims 1 to 14, wherein, in the requirement (B), the ratio (weight ratio) of the bulk combustion residues to the molded article of the gas generating composition before combustion is 10% or more.

16. The inflator for an air bag according to any one of claims 1 to 14, wherein, in the requirement (B), the ratio (weight ratio) of the bulk combustion residues to the molded article of the gas generating composition before combustion is 20% or more.

17. The inflator for an air bag according to any one of claims 1 to 14, wherein, in the requirement (B), the ratio (weight ratio) of the bulk combustion residues to the molded article of the gas generating composition before combustion is 30% or more.

18. The inflator for an air bag according to any one of claims 1 to 17, wherein, in the requirement (B), the upper limit of the ratio (weight ratio) of the bulk combustion residues to the molded article of the gas generating composition before combustion is 60%.

19. The inflator for an air bag according to any one of claims 1 to 18, wherein, in the requirement (B), the ratio (weight ratio) of the bulk combustion residues to the theoretical amount of residues is 50% or more.

20. The inflator for an air bag according to any one of claims 1 to 18, wherein, in the requirement (B), the ratio (weight ratio) of the bulk combustion residues to the theoretical amount of residues is 80% or more.

21. The inflator for an air bag according to any one of claims 1 to 18, wherein, in the requirement (B), the ratio (weight ratio) of the bulk combustion residues to the theoretical amount of residues is 90% or more.

22. The inflator for an air bag according to any one of claims 1 to 18, wherein, in the requirement (B), the ratio (weight ratio) of the bulk combustion residues to the theoretical amount of residues is 95% or more.

23. The inflator for an air bag according to any one of claims 1 to 22, wherein the metal content in the molded article of the gas generating composition is 20 to 50% by weight.

24. The inflator for an air bag according to any one of claims 1 to 22, wherein the metal content in the molded article of the gas generating composition is 20 to 45% by weight.

25. The inflator for an air bag according to any one of claims 2 to 24, wherein the porous dividing member comprises a single-layer body or a laminated body consisting of two or more layers having different functions.

26. The inflator for an air bag according to any one of claims 2 to 25, wherein, when the porous dividing member comprises a single-layer body, the porous dividing member is a supporting member having a first leakage preventing function of preventing leakage of the molded article of the gas generating composition from the gas discharging port at least before and during combustion.

27. The inflator for an air bag according to claim 26, wherein the supporting member has a second leakage preventing function of preventing leakage of the combustion residues from the gas discharging port during and after combustion.

28. The inflator for an air bag according to any one of claims 2 to 27, wherein the porous dividing member comprises a laminated body of two or more layers, the porous dividing member has one, two or three members selected from the group consisting of a retaining member for fixing the supporting member, a protecting member for preventing deformation of the supporting member and a coolant for cooling a combustion gas, in addition to the supporting member having the first leakage preventing function, or having the first and second leakage preventing functions.

29. The inflator for an air bag according to any one of claims 2 to 28, wherein the porous dividing member does not substantially cool a combustion gas.

30. The inflator for an air bag according to any one of claims 2 to 29, wherein the pressure loss, of the combustion gas, to the porous dividing member, is 10 kPa or less in the atmosphere at 20°

C. to 1000 L/min of air stream.

31. The inflator for an air bag according to any one of claims 2 to 29, wherein the pressure loss, of the combustion gas, to the porous dividing member, is 5 kPa or less in the atmosphere at 20°

C. to 1000 L/min of air stream.

32. The inflator for an air bag according to any one of claims 2 to 29, wherein the pressure loss, of the combustion gas, to the porous dividing member, is 1 kPa or less in the atmosphere at 20°

C. to 1000 L/min of air stream.

33. The inflator for an air bag according to any one of claims 2 to 29, wherein the pressure loss, of the combustion gas, to the porous dividing member, is 0.1 kPa or less, or there is substantially no pressure loss in the atmosphere at 20°

C. to 1000 L/min of air stream.

34. The inflator for an air bag according to any one of claims 2 to 33, which has a gap between the porous dividing member and the gas discharging port.

35. The inflator for an air bag according to any one of claims 1 to 34, wherein the molded article of the gas generating composition containing a metal component comprises a non-azide, gas generating agent containing (a) a fuel and (b) a metal-containing oxidizing agent.

36. The inflator for an air bag according to claim 35, wherein the (a) fuel is a nitrogen-containing compound.

37. The inflator for an air bag according to claim 35 or 36, wherein the (a) fuel is a triazine derivative, a triazole derivative, a tetrazole derivative, a guanidine derivative, an azodicarbonamide derivative or a hydrazine derivative.

38. The inflator for an air bag according to claim 37, wherein the triazine derivative is a member selected from the group consisting of triazine, melamine, trihydrazinotriazine, trimethylol melamine, alkylated methylol melamine, ammeline, ammelide, ammeland, cyanuric acid, a cyanuric acid derivative, melam, melem, melamine nitrate, melamine perchlorate and nitrated melamine.

39. The inflator for an air bag according to claim 37, wherein the triazole derivative, tetrazole derivative, guanidine derivative, azodicarbonamide derivative and hydrazine derivative are 5-oxo-1,2,4-triazole, tetrazole, 5-aminotetrazole, 5,5′

-bi-1H-tetrazole, guanidine, nitroguanidine, cyanoguanidine, triaminoguanidine nitrate, guanidine nitrate, guanidine carbonate, burette, azodicarbonamide, carbohydrazide, carbohydrazide nitrate complexes, dihydrazide oxalate and hydrazine nitrate complexes.

40. The inflator for an air bag according to any one of claims 36 to 39, wherein the (b) metal-containing oxidizing agent contained in the molded article of the gas generating composition is an oxygen-containing oxidizing agent.

41. The inflator for an air bag according to any one of claims 36 to 40, wherein the (b) metal-containing oxidizing agent contained in the molded article of the gas generating composition is at least one member selected from an oxy acid salt, a metal oxide, a metal complex oxide, a metal peroxide and a basic metal nitrate.

42. The inflator for an air bag according to claim 41, wherein the basic metal nitrate is at least one member selected from the group consisting of basic copper nitrate, basic cobalt nitrate, basic zinc nitrate, basic manganese nitrate, basic iron nitrate, basic molybdenum nitrate, basic bismuth nitrate and basic cerium nitrate.

43. The inflator for an air bag according to any one of claims 36 to 41, wherein the content of the (a) component in the molded article of the gas generating composition is 5 to 60% by weight, and the content of the (b) component therein is 40 to 95% by weight.

44. The inflator for an air bag according to any one of claims 36 to 42, wherein the molded article of the gas generating composition further comprises at least either of (c) a binder and (d) an additive.

45. The inflator for an air bag according to claim 44, wherein the binder as the (c) component contained in the molded article of the gas generating composition is at least one member selected from the group consisting of carboxymethyl cellulose, carboxymethyl cellulose sodium salt, carboxymethyl cellulose potassium salt, carboxymethyl cellulose ammonium salt, cellulose acetate, cellulose acetate butyrate, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, ethyl hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl ethyl cellulose, fine crystalline cellulose, polyacrylamide, aminated polyacrylamide, polyacryl hydrazide, acrylamide-metal acrylate copolymers, polyacrylamide-polyacrylate copolymers, polyvinyl alcohol, acrylic rubber, guar gum, starch and silicone.

46. The inflator for an air bag according to claim 44, wherein the additive as the (d) component contained in the molded article of the gas generating composition is at least one selected from the group consisting of a metal oxide selected from copper oxide, iron oxide, zinc oxide, cobalt oxide, manganese oxide, molybdenum oxide, nickel oxide, bismuth oxide, silica and aluminum, a metal hydroxide selected from the group consisting of aluminum hydroxide, cobalt hydroxide and iron hydroxide, a metal carbonate or a basic metal carbonate selected from cobalt carbonate, calcium carbonate, basic zinc carbonate and basic copper carbonate, a complex compound of metal oxide or metal hydroxide selected from the group consisting of Japanese acid clay, kaolin, talc, bentonite, diatomaceous earth and hydrotalcite, a metal acid salt selected from the group consisting of sodium silicate, mica, molybdate, cobalt molybdate and ammonium molybdate, silicone, molybdenum disulfide, calcium stearate, silicon nitride, silicon carbide and a catalyst having ruthenium carried on alumina or silica.

47. The inflator for an air bag according to any one of claims 43 to 46, wherein the content of the (c) component in the molded article of the gas generating composition is 0.1 to 15% by weight, and the content of the (d) component therein is 0.1 to 20% by weight.

48. The inflator for an air bag according to any one of claims 35 to 47, wherein the (a) component in the molded article of the gas generating composition is melamine, and the (b) component therein is basic copper nitrate.

49. The inflator for an air bag according to any one of claims 43 to 47, wherein the molded article of the gas generating composition comprises (a) 10 to 25% by weight of melamine, (b) 60 to 80% by weight of basic copper nitrate, (c) 0.1 to 10% by weight of carboxy methyl cellulose sodium salt, and (d) 1 to 15% by weight of aluminum hydroxide or (d) 1 to 10% by weight of cobalt oxide.

50. The inflator for an air bag according to any one of claims 43 to 47, wherein the molded article of the gas generating composition comprises (a) 10 to 25% by weight of trihydrazinotriazine, (b) 60 to 80% by weight of basic copper nitrate, (c) 0.1 to 10% by weight of carboxy methyl cellulose sodium salt, and (d) 1 to 15% by weight of aluminum hydroxide or (d) 1 to 10% by weight of cobalt oxide.

51. The inflator for an air bag according to any one of claims 1 to 50, wherein the molded article of the gas generating composition is in the form of a cylinder, a single-perforated cylinder, a perforated cylinder, a doughnut or a pellet.

52. An airbag apparatus including an inflator for an air bag, an impact sensor which, upon sensing impact, actuates the inflator, an airbag expanding by introducing a gas generated in the inflator into the airbag, and a module case accommodating the airbag, wherein the inflator for an air bag is an inflator for an air bag described in any one of claims 1 to 51.

2. An inflator for an air bag comprising, in a housing having a gas discharging port, a combustion chamber accommodating a molded article of a gas generating composition which is burnt to generate a gas and an ignition means to ignite the molded article of a gas generating composition, wherein a porous dividing member is arranged between the gas discharging port and the molded article of the gas generating composition, the combustion gas is discharged via the dividing member from the gas discharging port, and the molded article of the gas generating composition contains a metal component and meets the following requirements (A) and (B):

(A) the (theoretical) combustion flame temperature of the molded article of the gas generating composition is 2000°

C. or less, and part or the whole of the metal or metal oxide after combustion of the molded article of the gas generating composition has a melting point not lower than the combustion flame temperature; and

(B) bulk combustion residues remain in the combustion chamber at the time of combustion of the molded article of the gas generating composition.