Gas-generating agent for air bag

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 m.sup.2 /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 m.sup.2 /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.

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 m.sup.2 /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 m.sup.2 /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.