Basic metal nitrate, process for producing the same and gas generating agent composition

Abstract

A basic metal nitrate suitable as an oxidizing agent for a gas generating agent, which is a basic metal nitrate having a good thermal stability and meeting at least one requirement of the following (a) to (d): (a) a particle diameter of 0.5 to 40 μm; (b) a degree of crystallinity having 0.4 deg or less of a half band width of the peak in the X-ray analysis; (c) an initiation temperature of weight loss being 220° C. or higher according to TG-DTA analysis; and (d) an impurity content of 1,000 ppm or less based on Na atom. Also, a gas generating composition which has a low toxicity, a high burning rate, and a low combustion temperature and which is used in a gas generator for an air bag. The gas generating composition comprises (a) tetrazole derivatives, guanidine derivatives or a mixture thereof, (b) a basic metal nitrate, and (c) a binder and/or a slag-forming agent.

1 . A gas generating composition comprising a basic metal nitrate meeting at least one requirement of the following (b) to (d): 
 (b) a degree of crystallinity having 0.35 deg or less of a half band width of the peak in the X-ray diffraction;    (c) an initiation temperature of weight loss being 220° C. or higher according to TG-DTA analysis; and    (d) an impurity content of 1,000 ppm or less based on Na atom.    
   
   
       2 . The gas generating composition as claimed in  claim 1 , wherein the basic metal nitrate is a basic copper nitrate.  
   
   
       3 . A gas generating composition comprising a fuel and the basic metal nitrate as defined in  claim 1 .  
   
   
       4 . A gas generating composition comprising a fuel and a basic metal nitrate, the basic metal nitrate meeting at least one requirement selected from (a-2) or (a-3): 
 (a-2) a specific surface area of particles being 0.4 to 6.0 m 2 /g;    (a-3) a bulk density of particles being 0.4 g/ml or more.    
   
   
       5 . The gas generating composition as claimed in  claim 4 , comprising a fuel and a basic metal nitrate, the basic metal nitrate meeting at least one requirement selected from (a-2) or (a-3) and further (b) to (d): 
 (b) a degree of crystallinity having 0.35 deg or less of a half band width of the peak in the X-ray diffraction;    (c) an initiation temperature of weight loss being 220° C. or higher according to TG-DTA analysis; and    (d) an impurity content of 1,000 ppm or less based on Na atom.    
   
   
       6 . A gas generating composition comprising a fuel and a basic metal nitrate, the basic metal nitrate being in the form of secondary particles of coagulated principal particles, the secondary particles meeting at least one requirement selected from (a-2) or (a-3): 
 (a-2) a specific surface area of particles being 0.4 to 6.0 m 2 /g;    (a-3) a bulk density of particles being 0.4 g/ml or more.    
   
   
       7 . The gas generating composition as claimed in  claim 6 , comprising a fuel and a basic metal nitrate, the basic metal nitrate meeting at least one requirement selected from (a-2) or (a-3) and further the following (b) to (d): 
 (b) a degree of crystallinity having 0.35 deg or less of a half band width of the peak in the X-ray diffraction;    (c) an initiation temperature of weight loss being 220° C. or higher according to TG-DTA analysis; and    (d) an impurity content of 1,000 ppm or less based on Na atom.    
   
   
       8 . The gas generating composition as claimed in  claim 6 , wherein the basic metal nitrate in the form of the secondary particles is formed by coagulating a large number of principal particles having the form of needles to plates and/or spheres to similar shapes thereto.  
   
   
       9 . The gas generating composition as claimed in  claim 4 , wherein the fuel is a nitrogen-containing compound selected from the group consisting of guanidine derivatives, azole derivatives, triazine derivatives and transition metal complexes.  
   
   
       10 . The gas generating composition as claimed in  claim 9 , wherein the fuel is nitroguanidine.  
   
   
       11 . The gas generating composition as claimed in  claim 4 , wherein the basic metal nitrate is a basic copper nitrate.  
   
   
       12 . The gas generating composition as claimed in  claim 4 , which further comprises an additive.  
   
   
       13 . The gas generating composition as claimed in  claim 12 , wherein the additive is guar gum.  
   
   
       14 . The gas generating composition as claimed in  claim 4 , which has a weight loss ratio of 2.0% by weight or less when it is allowed to stand in an atmosphere of a temperature of 1100 for 400 hours.  
   
   
       15 . The gas generating composition as claimed in  claim 3 , wherein said basic metal nitrate is a basic copper nitrate.  
   
   
       16 . A gas generating composition comprising (a) tetrazole derivatives, guanidine derivatives or a mixture thereof, (b) a basic metal nitrate and (d) a combustion-improving agent.  
   
   
       17 . A gas generating composition comprising (a) tetrazole derivatives, guanidine derivatives or a mixture thereof, (b) a basic metal nitrate, (c) a binder and/or a slag-forming agent, and (d) a combustion-improving agent.  
   
   
       18 . The gas generating composition as claimed in  claim 16 , wherein (d) the combustion-improving agent is at least one selected from the group consisting of silicon nitride, silica, a nitrite, a nitrate, a chlorate or a perchlorate of an alkali metal or an alkaline earth metal (KNO 3 , NaNO 3 , KClO 4 ), iron (III) hydroxide oxide [FeO(OH)], copper oxide, iron oxide, zinc oxide, cobalt oxide and manganese oxide.  
   
   
       19 . The gas generating composition as claimed in  claim 17 , wherein (d) the combustion-improving agent is at least one selected from the group consisting of silicon nitride, silica, a nitrite, a nitrate, a chlorate or a perchlorate of an alkali metal or an alkaline earth metal (KNO 3 , NaNO 3 , KClO 4 ), iron (III) hydroxide oxide [FeO(OH)], copper oxide, iron oxide, zinc oxide, cobalt oxide and manganese oxide.  
   
   
       20 . A gas generating composition comprising (a) tetrazole derivatives, guanidine derivatives or a mixture thereof and (b) a basic metal nitrate and meeting at least one requirement selected from the following (1) to (3): 
 (1) a weight loss ratio of the gas generating composition when the gas generating composition is retained in a closed state at 90° C. for 1,000 hours or at 110° C. for 400 hours is 2.0% or less,    (2) concentrations of trace gases contained in a gas generated by the combustion of the gas generating composition, as values measured in a 2,800-liter tank, 400 ppm or less for CO, 40 ppm or less for NO, 8 ppm or less for NO 2  and 100 ppm or less for NH 3 , and    (3) a maximum internal pressure in a gas generator on the combustion of the gas generating composition is 7,840 to 22,500 kPa.    
   
   
       21 . A gas generating composition comprising (a) tetrazole derivatives, guanidine derivatives or a mixture thereof, (b) a basic metal nitrate and (c) a binder and/or a slag-forming agent and meeting at least one requirement selected from the following (1) to (3): 
 (1) a weight loss ratio of the gas generating composition when the gas generating composition is retained in a closed state at 90° C. for 1,000 hours or at 110° C. for 400 hours is 2.0% or less,    (2) concentrations of trace gases contained in a gas generated by the combustion of the gas generating composition, as values measured in a 2,800-liter tank, 400 ppm or less for CO, 40 ppm or less for NO, 8 ppm or less for NO 2  and 100 ppm or less for NH 3 , and    (3) a maximum internal pressure in a gas generator on the combustion of the gas generating composition is 7,840 to 22,500 kPa.    
   
   
       22 . The gas generating composition as claimed in  claim 16 , wherein component (a) is a tetrazole derivative selected from the group consisting of tetrazole, 5-aminotetrazole, 5,5′-bi-1H-tetrazole, 5-nitroaminotetrazole, zinc salt of 5-aminotetrazole, copper salt of 5-aminotetrazole, bitetrazole, potassium salt of bitetrazole, sodium salt of bitetrazole, magnesium salt of bitetrazole, calcium salt of bitetrazole, diammonium salt of bitetrazole, copper salt of bitetrazole and melamine salt of bitetrazole.  
   
   
       23 . The gas generating composition as claimed in  claim 16 , wherein component (a) is a guanidine derivative selected from the group consisting of guanidine, mono-, di- or tri-aminoguanidine nitrate, guanidine nitrate, guanidine carbonate, nitroguanidine, dicyandiamide and nitroaminoguanidine nitrate.  
   
   
       24 . The gas generating composition as claimed in  claim 16 , wherein component (b) is a basic metal nitrate selected from the group consisting of a basic copper nitrate, a basic cobalt nitrate, a basic zinc nitrate, a basic manganese nitrate, a basic iron nitrate, a basic molybdenum nitrate, a basic bismuth nitrate and a basic cerium nitrate.  
   
   
       25 . The gas generating composition as claimed in  claim 24 , wherein component (b) is a mixture of a basic metal nitrate and at least one other oxidizing agent.  
   
   
       26 . The gas generating composition as claimed in  claim 25 , wherein component (b) is a mixture of a basic metal nitrate and at least one other oxidizing agent which includes an alkali metal nitrate.  
   
   
       27 . The gas generating composition as claimed in  claim 26 , wherein when component (b) is a mixture, the alkali metal nitrate contained as at least one other oxidizing agent is potassium nitrate.  
   
   
       28 . The gas generating composition as claimed in  claim 25 , wherein the content of the basic metal nitrate in the mixture is 55 to 99.9% by weight.  
   
   
       29 . The gas generating composition as claimed in  claim 17 , wherein the binder and/or the slag-forming agent as component (c) is not crosslinkable and is at least one member selected from the group consisting of polyacrylic amide, aminated compounds of polyacrylic amide, polyacrylic hydrazide, a copolymer of an acrylic amide and a metal salt of acrylic acid, a copolymer of polyacrylic amide and polyacrylic ester, polyvinyl alcohol, acrylic rubber, guar gum, starch, polysaccharides including starch, silicone, molybdenum disulfide, Japanese acid clay, talc, bentonite, diatomaceous earth, kaolin, calcium stearate, silica, alumina, sodium silicate, silicon nitrate, silicon carbide, hydrotalcite, mica, a metal oxide, a metal hydroxide, a metal carbonate, a basic metal carbonate, and a molybdate.  
   
   
       30 . The gas generating composition as claimed in  claim 29 , wherein component (c) is a metal oxide selected from the group consisting of copper oxide, iron oxide, zinc oxide, cobalt oxide, manganese oxide, molybdenum oxide, nickel oxide, and bismuth oxide, a metal hydroxide selected from the group consisting of cobalt hydroxide and aluminum hydroxide, a metal carbonate or a basic metal carbonate selected from the group consisting of calcium carbonate, cobalt carbonate, a basic zinc carbonate, and a basic copper carbonate, or a molybdate selected from the group consisting of cobalt molybdate and ammonium molybdate.  
   
   
       31 . A gas generating composition which comprises (a) nitroguanidine, and (b) a basic copper nitrate.  
   
   
       32 . The gas generating composition as claimed in  claim 31 , which comprises 30 to 70% by weight of (a) nitroguanidine and 30 to 70% by weight of (b) a basic copper nitrate.  
   
   
       33 . The gas generating composition as claimed in  claim 31 , which comprises (a) nitroguanidine, (b) a basic copper nitrate and (c) sodium carboxymethylcellulose.  
   
   
       34 . The gas generating composition as claimed in  claim 33 , which comprises 15 to 55% by weight of (a) nitroguanidine, 45 to 70% by weight of (b) a basic copper nitrate and 0.1 to 15% by weight of (C) sodium carboxymethylcellulose.  
   
   
       35 . The gas generating composition as claimed in  claim 31 , which comprises (a) nitroguanidine, (b) a basic copper nitrate, (c-1) sodium carboxymethylcellulose, and (c-2) a member selected from the group consisting of polyacrylic amide, aminated compounds of polyacrylic amide, polyacrylic hydrazide, a copolymer of an acrylic amide and a metal salt of acrylic acid, a copolymer of polyacrylic amide and polyacrylic ester, polyvinyl alcohol, acrylic rubber, guar gum, starch, polysaccharides including starch, silicone, molybdenum disulfide, Japanese acid clay, talc, bentonite, diatomaceous earth, kaolin, calcium stearate, silica, alumina, sodium silicate, silicon nitrate, silicon carbide, hydrotalcite, mica, a metal oxide, a metal hydroxide, a metal carbonate, a basic metal carbonate, and a molybdate.  
   
   
       36 . The gas generating composition as claimed in  claim 35 , which comprises 15 to 50% by weight of (a) nitroguanidine, 30 to 65% by weight of (b) a basic copper nitrate, 0.1 to 15% by weight of (c-1) sodium carboxymethylcellulose and 1 to 40% by weight of (c-2).  
   
   
       37 . The gas generating composition as claimed in  claim 31 , which comprises (a) nitroguanidine, (b) a basic copper nitrate, and (c) guar gum.  
   
   
       38 . The gas generating composition as claimed in  claim 37 , which comprises 20 to 60% by weight of (a) nitroguanidine, 35 to 75% by weight of (b) a basic copper nitrate and 0.1 to 10% by weight of guar gum.  
   
   
       39 . The gas generating composition as claimed in  claim 37 , which comprises (a) nitroguanidine, (b) a basic copper nitrate, (c-1) guar gum, and (c-2) a member selected from the group consisting of polyacrylic amide, aminated compounds of polyacrylic amide, polyacrylic hydrazide, a copolymer of an acrylic amide and a metal salt of acrylic acid, a copolymer of polyacrylic amide and polyacrylic ester, polyvinyl alcohol, acrylic rubber, guar gum, starch, polysaccharides including starch, silicone, molybdenum disulfide, Japanese acid clay, talc, bentonite, diatomaceous earth, kaolin, calcium stearate, silica, alumina, sodium silicate, silicon nitrate, silicon carbide, hydrotalcite, mica, a metal oxide, a metal hydroxide, a metal carbonate, a basic metal carbonate, and a molybdate.  
   
   
       40 . The gas generating composition as claimed in  claim 39 , which comprises 20 to 60% by weight of (a) nitroguanidine, 30 to 70% by weight of (b) a basic copper nitrate, 0.1 to 10% by weight of (c-1) guar gum, and 0.1 to 10% by weight of (c-2).  
   
   
       41 . The gas generating composition as claimed in  claim 17 , which comprises (a) nitroguanidine, (b) a basic copper nitrate, (c) guar gum, and (d) a combustion-improving agent.  
   
   
       42 . The gas generating composition as claimed in  claim 41 , which comprises 20 to 60% by weight of (a) nitroguanidine, 35 to 75% by weight of (b) a basic copper nitrate, 0.1 to 10% by weight of (c) guar gum and 0.1 to 15% by weight of (d) a combustion-improving agent.  
   
   
       43 . The gas generating composition as claimed in  claim 41 , wherein (d) the combustion-improving agent is silica.  
   
   
       44 . The gas generating composition as claimed in  claim 31 , which comprises a mixture of a basic copper nitrate and potassium nitrate as component (b).  
   
   
       45 . A gas generating composition which comprises (a) dicyandiamide and (b) a basic copper nitrate.  
   
   
       46 . The gas generating composition as claimed in  claim 45 , which comprises 15 to 30% by weight of (a) dicyandiamide and 70 to 85% by weight of (b) a basic copper nitrate.  
   
   
       47 . The gas generating composition as claimed in  claim 45 , which comprises (a) dicyandiamide, (b) a basic copper nitrate, and (c) sodium carboxymethylcellulose.  
   
   
       48 . The gas generating composition as claimed in  claim 47 , which comprises 15 to 25% by weight of (a) dicyandiamide, 60 to 80% by weight of (b) a basic copper nitrate, and 0.1 to 20% by weight of (c) sodium carboxymethylcellulose.  
   
   
       49 . The gas generating composition as claimed in  claim 31 , which comprises (a) dicyandiamide, (b) a basic copper nitrate, (c-1) sodium carboxymethylcellulose, and (c-2) a member selected from the group consisting of polyacrylic amide, aminated compounds of polyacrylic amide, polyacrylic hydrazide, a copolymer of an acrylic amide and a metal salt of acrylic acid, a copolymer of polyacrylic amide and polyacrylic ester, polyvinyl alcohol, acrylic rubber, guar gum, starch, polysaccharides including starch, silicone, molybdenum disulfide, Japanese acid clay, talc, bentonite, diatomaceous earth, kaolin, calcium stearate, silica, alumina, sodium silicate, silicon nitrate, silicon carbide, hydrotalcite, mica, a metal oxide, a metal hydroxide, a metal carbonate, a basic metal carbonate, and a molybdate.  
   
   
       50 . The gas generating composition as claimed in  claim 49 , which comprises 15 to 25% by weight of (a) dicyandiamide, 55 to 75% by weight of (b) a basic copper nitrate, 0 to 10% by weight of (c-1) sodium carboxymethylcellulose, and 1 to 20% by weight of (c-2).  
   
   
       51 . The gas generating composition as claimed in  claim 45 , which comprises a mixture of a basic copper nitrate and potassium nitrate as component (b).  
   
   
       52 . A gas generating composition comprising (a) guanidine nitrate, (b) a basic copper nitrate, and (c) sodium carboxymethylcellulose.  
   
   
       53 . The gas generating composition as claimed in  claim 52 , which comprises 15 to 60% by weight of (a) guanidine nitrate, 40 to 70% by weight of (b) a basic copper nitrate, and 0.1 to 15% by weight of (c) sodium carboxymethylcellulose.  
   
   
       54 . A gas generating composition comprising (a) guanidine nitrate, (b) a basic copper nitrate, (c-1) sodium carboxymethylcellulose, and (c-2) a member selected from the group consisting of polyacrylic amide, aminated compounds of polyacrylic amide, polyacrylic hydrazide, a copolymer of an acrylic amide and a metal salt of acrylic acid, a copolymer of polyacrylic amide and polyacrylic ester, polyvinyl alcohol, acrylic rubber, guar gum, starch, polysaccharides including starch, silicone, molybdenum disulfide, Japanese acid clay, talc, bentonite, diatomaceous earth, kaolin, calcium stearate, silica, alumina, sodium silicate, silicon nitrate, silicon carbide, hydrotalcite, mica, a metal oxide, a metal hydroxide, a metal carbonate, a basic metal carbonate, and a molybdate.  
   
   
       55 . The gas generating composition as claimed in  claim 54 , which comprises 15 to 55% by weight of (a) guanidine nitrate, 25 to 60% by weight of (b) a basic copper nitrate, 0.1 to 15% by weight of (c-1) sodium carboxymethylcellulose, and 1 to 40% by weight of (c-2).  
   
   
       56 . The gas generating composition as claimed in  claim 52 , which comprises a mixture of a basic copper nitrate and potassium nitrate as component (b).  
   
   
       57 . A molded article in the form of a single-perforated cylinder, a perforated (porous) cylinder or pellets, the molded article being obtained from the gas generating composition as claimed in  claim 1 .  
   
   
       58 . An inflator for an air bag using the gas generating composition as claimed in  claim 1 .  
   
   
       59 . An inflator for an air bag using the molded article as claimed in  claim 57.