Gas generating material

• US 4,698,107 A
• Filed: 12/24/1986
• Issued: 10/06/1987
• Est. Priority Date: 12/24/1986
• Status: Expired due to Fees

• Current Assignee: TRW Vehicle Safety Systems Incorporated (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: TRW Automotive Products, Inc. (Northrop Grumman Corporation)
• Inventors: Hamilton, Brian K., Goetz, George W.
• Primary Examiner(s): Lechert, Jr., Stephen J.
• Application Number:
  US06/946,705
• Time in Patent Office: 286 Days
• Field of Search: 149/7, 149/35, 149/61, 149/41, 102/531, 102/286, 280/728
• US Class Current: 149/7
• CPC Class Codes: B60R 21/2644 using only solid reacting substances, e.g. pellets, powder
• CPC Class Codes: C06B 45/16 the layer or zone containing at least one inorganic component from the group of azide, fulminate, phosphorus and phosphide
• CPC Class Codes: C06D 5/06 by reaction of two or more solids

Abstract

Structure for generating nitrogen gas for inflating an air bag vehicle occupant restraint comprises a grain made of an azide based material which generates gas upon combustion. The grain has an ignition enhancing coating thereon consisting essentially of 20 to 50% by weight of an alkali metal azide, 25 to 35% by weight of an inorganic oxidizer, 10 to 15% by weight of a fluoroelastomer binder, 15 to 25% by weight of magnesium, and 1 to 3% by weight of fumed silicon dioxide. The coating may also include 1 to 6% by weight of graphite as a roughening agent.

Claims

1. Structure for generating gas, said structure comprising:

a grain made of an azide based material which generates gas upon combustion;

said grain having an ignition enhancing coating thereon comprising;

20 to 50% by weight of an alkali metal azide,

25 to 35% by weight of an inorganic oxidizer,

10 to 15% by weight of a fluoroelastomer binder,

15 to 25% by weight of magnesium, and

1 to 3% by weight of fumed silicon dioxide.

2. The structure defined in claim 1 wherein said alkali metal azide is sodium azide and said inorganic oxidizer is sodium nitrate.

3. The structure defined in claim 1 further including 1-6% by weight of graphite fiber.

4. The structure defined in claim 1 wherein said coating comprises;

about 43% by weight of sodium azide,

about 28% by weight of sodium nitrate,

about 2% by weight of fumed silicon dioxide,

about 10% by weight of a fluoroelastomer, and

about 16% by weight of magnesium.

5. The structure defined in claim 1 wherein said coating weight comprises from about 1 to about 4 percent of the weight of the uncoated grain.

6. The structure as defined in claim 1 wherein said grain has opposite axial ends and passages which extend axially through the grain and intersect said opposite axial ends.

7. The structure as defined in claim 1 wherein said grain comprises a gas generating material which contains from about 2 to about 6% by weight of graphite fibers, said graphite fibers having a diameter of 3-15 microns and an average length of 40 to 125 thousandths of an inch.

8. The structure as defined in claim 6 wherein said material further includes:

61-68% by weight of sodium azide,

0-5% by weight of sodium nitrate,

0-5% by weight of bentonite,

23-28% by weight of iron oxide, and

1-2% by weight of fumed silica.