Gas-generating agent for air bag

• US 4,021,275 A
• Filed: 10/29/1975
• Issued: 05/03/1977
• Est. Priority Date: 04/23/1975
• Status: Expired due to Term

• Current Assignee: Daicel Corporation
• Original Assignee: Daicel Corporation
• Inventors: Naganuma, Kazuo, Kishi, Kazuo
• Primary Examiner(s): Padgett, Benjamin R.
• Assistant Examiner(s): Gron, T. S.
• Application Number:
  US05/626,725
• Time in Patent Office: 552 Days
• Field of Search: 149/35, 252/188.3 R, 252/350, 23/281, 280/150 AB, 252/741, 264/3 C, 264/3 E
• US Class Current: 149/35
• CPC Class Codes: C06B 23/001 Fillers, gelling and thickening agents (e.g. fibres) , absorbents for nitroglycerine binders, plasticisers for propellants C06B45/10; crosslinking or curing agents C06B45/10
• CPC Class Codes: C06D 5/06 by reaction of two or more solids

Abstract

A gas-generating agent for inflating air bags comprises finely divided particles of a co-precipitation compound made by the following steps: (1) uniformly mixing in water to form an aqueous solution a composition comprising (a) one or a mixture of two or more alkali metal azides and/or alkaline earth metal azides and (b) an aqueous solution of a composition comprising one or a mixture of two or more nitrates or perchlorates of alkali metals or alkaline earth metals; or mixing (a) and (b) plus (c) finely divided particles of silicon dioxide; or mixing (a), (b) and (c) plus (d) fine glass powder; (2) mixing the resulting solution or suspension with a water-soluble organic solvent; and (3) separating and drying the co-precipitation compound thus obtained. The gas-generating agent will not produce toxic compounds such as sodium metal and sodium peroxide which might injure the car driver and passengers. Further, when low softening glass is added, the maximum temperature of combustion will be lowered.

Claims

1. A gas generating agent consisting essentially of finely divided particles of a co-precipitation product obtained by the steps of

(1) preparing a uniform aqueous solution consisting essentially of (a) an azide component consisting of one or a mixture of two or more azides selected from the group consisting of alkali metal azides and alkaline earth metal azides, and (b) an oxidant component consisting of one or a mixture of two or more oxidants selected from the group consisting of alkali metal nitrates, alkali metal perchlorates, alkaline earth metal nitrates and alkaline earth metal perchlorates;

(2) adding said aqueous solution to water-soluble organic solvent and thereby precipitating a co-precipitation product of (a) and (b) wherein the weight ratio of a/b is in the range of from 95/5 to 50/50;

(3) separating and drying the co-precipitation product.

2. A gas-generating agent as set forth in claim 1 wherein the water-soluble organic solvent is selected from the group consisting of methanol, ethanol, acetone, and iso-propanol.

3. A gas generating agent consisting essentially of finely divided particles of a co-precipitation product obtained by the steps of

(1) preparing a uniform aqueous dispersion consisting essentially of an aqueous solution of (a) an azide component consisting of one or a mixture of two or more azides selected from the group consisting of alkali metal azides and alkaline earth metal azides, and (b) an oxidant component consisting of one or a mixture of two or more oxidants selected from the group consisting of alkali metal nitrates, alkali metal perchlorates, alkaline earth metal nitrates and alkaline earth metal perchlorates, said solution having dispersed therein (c) particles of silicon dioxide selected from the group consisting of (i) a flocculate having an overall flocculate size of 2 to 150 microns and a surface area of 50 to 450 m² /g and consisting of spherical silicon dioxide powder having a particle size of 1 to 100 millimicrons, and (ii) colloidal silica having a particle size of 1 to 100 millimicrons and a surface area of from 22 to 120 m² /g;

(2) adding said aqueous dispersion to water-soluble organic solvent and thereby precipitating a co-precipitation product of (a), (b) and (c), wherein the weight ratio of a/b is in the range of from 95/5 to 50/50 and the weight ratio of a plus b/c is from 97/3 to 55/45;

(3) separating and drying the co-precipitation product.

4. A gas-generating agent as set forth in claim 3 wherein the water-soluble organic solvent is selected from the group consisting of methanol, ethanol, acetone, and iso-propanol.

5. A gas generating agent consisting essentially of finely divided particles of a co-precipitation product obtained by the steps of

(1) preparing a uniform aqueous dispersion consisting essentially of an aqueous solution of (a) an azide component consisting of one or a mixture of two or more azides selected from the group consisting of alkali metal azides and alkaline earth metal azides, and (b) an oxidant component consisting of one or a mixture of two or more oxidants selected from the group consisting of alkali metal nitrates, alkali metal perchlorates, alkaline earth metal nitrates and alkaline earth metal perchlorates, said solution having dispersed therein (c) particles of silicon dioxide selected from the group consisting of (i) a flocculate having an overall flocculate size of 2 to 150 microns and a surface area of 50 to 450 m² /g and consisting of spherical silicon dioxide powder having a particle size of 1 to 100 millimicrons, and (ii) colloidal silica having a particle size of 1 to 100 millimicrons and a surface area of from 22 to 120 m² /g, and (d) particles of glass having a low softening temperature and having a particle size of from 5 to 300 microns;

(2) adding said aqueous dispersion to water-soluble organic solvent and thereby precipitating a co-precipitation product of (a), (b), (c) and (d) wherein the weight ratio of a/b is in the range of from 95/5 to 50/50, the weight ratio of a plus b/c is from 97/3 to 55/45, and containing from 3 to 50 weight percent of (d), based on the total weight of the co-precipitation product;

(3) separating and drying the co-precipitation product.

6. A gas-generating agent as set forth in claim 5 wherein the glass is a low softening glass essentially consisting of 5 to 75% by weight of SiO₂, 0 to 50% by weight of CaO, 1 to 40% by weight of Al₂ O₃, 0 to 25% by weight of B₂ O₃, 0 to 20% by weight of K₂ O, 0 to 20% by weight of Na₂ O, 0 to 15% by weight of MgO, and 0 to 60% by weight of PbO.

7. A gas-generating agent as set forth in claim 5 wherein the water-soluble organic solvent is selected from the group consisting of methanol, ethanol, acetone, and iso-propanol.