JP5422096B2 - Gas generant composition - Google Patents

Description

  The present invention relates to a gas generant composition suitable for an airbag restraint system such as an automobile.

The gas generant composition used in airbag restraint systems for automobiles, etc. has a low amount of nitrogen oxides and carbon monoxide in the generated gas, a low amount of mist in the generated gas, and a reduction in combustion temperature. There are various requests such as what can be done.
JP 2001-220282 A JP 2004-67424 A JP 11-343192 A JP 2006-76849 A

  Among the prior arts, the gas generant composition disclosed in the inventions of Patent Documents 1 and 2 has a low amount of nitrogen oxides, carbon monoxide, and the like in the generated gas, and is used for cooling by reducing the combustion temperature. This is excellent in that the amount of the coolant filter can be reduced. However, the gas generant compositions disclosed in the inventions of Patent Documents 1 and 2 have room for further improvement in terms of ignitability in a situation where the temperature is low such as in winter.

  The present invention provides a gas generant composition having good ignitability in a wide range of temperatures from low temperature to high temperature, a low combustion temperature, and a small amount of nitrogen oxide, carbon monoxide and the like in the generated gas. Let it be an issue.

As a means for solving the problems, the present invention provides a gas generant composition containing melamine containing a fuel and an oxidant and having a particle diameter (D ₅₀ ) of 35 μm or less as measured by a laser scattering method. .

The gas generating composition according to claim 1, further comprising guanidine nitrate as a fuel as another means for solving the problem;
The gas generant composition according to claim 1 or 2, comprising basic copper nitrate and / or basic copper carbonate as an oxidizing agent;
The basic copper nitrate and the basic copper carbonate are used in combination as an oxidizing agent, and the ratio in that case is 1 to 100 parts by mass of the basic copper carbonate with respect to 100 parts by mass of the basic copper nitrate. Any one of the gas generant compositions;
Furthermore, the gas generating composition in any one of Claims 1-4 containing aluminum hydroxide is provided.

  Since the gas generant composition of the present invention contains melamine having a small particle size as a fuel component, it has good ignitability despite a low combustion temperature, clean gas generation, nitrogen oxide, ammonia The content of carbon monoxide has been reduced.

The gas generant composition of the present invention contains melamine (hereinafter referred to as “fine powdered melamine”) having a particle size (D ₅₀ ) of 35 μm or less measured by a laser scattering method as a fuel. The particle diameter (D ₅₀ ) of the fine melamine is preferably 20 μm or less, and more preferably 10 μm or less. The fine melamine having such a particle size has good ignitability in a range from a low temperature (for example, −40 ° C.) to a high temperature (for example, 80 ° C.) despite the low combustion temperature.

  The gas generating composition of the present invention may use only the fine melamine described above as a fuel, but may also use the above-mentioned fine melamine and other known nitrogen-containing compounds in combination. When the fine melamine and other known nitrogen-containing compounds are used in combination, the content of the fine melamine is preferably 1% by mass or more, and more preferably 3% by mass or more.

  Other known nitrogen-containing compounds include: tetrazole compounds including 5-aminotetrazole and bitetrazole ammonium salts; guanidine compounds including nitroguanidine, guanidine nitrate and dicyandiamide; trimethylol melamine, alkylated methylol melamine, ammelin and ammeland Melamine nitrate, melamine perchlorate, trihydrazinotriazine, or one or more selected from triazine compounds including melamine nitrated compounds. Among these, guanidine compounds including nitroguanidine, guanidine nitrate, and dicyandiamide are preferable, and in particular, combined with the melamine described above, suppresses an excessive decrease in the combustion temperature of the gas generant composition and adjusts to a suitable range. Guanidine nitrate is preferred because it can.

  The ratio in the case of using the above-mentioned fine melamine and guanidine nitrate in combination is preferably 10 to 1500 parts by mass, more preferably 25 to 1000 parts by mass, and further 50 to 750 parts by mass with respect to 100 parts by mass of fine melamine. preferable.

  In the gas generant composition of the present invention, the fuel content is preferably 5 to 50% by mass, more preferably 7.5 to 45% by mass, and still more preferably 10 to 40% by mass.

  The gas generant composition of the present invention preferably contains at least one of basic copper nitrate and basic copper carbonate as an oxidizing agent, but if necessary, a known oxidizing agent may be used in combination. Also good. Basic copper nitrate and basic copper carbonate can be used individually, but when basic copper nitrate and basic copper carbonate are used in combination, the combustion temperature of the gas generant composition may be lowered. This is preferable because the amount of nitrogen oxides, carbon monoxide and the like in the generated gas can be reduced.

  When using basic copper nitrate and basic copper carbonate together, it is preferable to reduce the content ratio of basic copper carbonate, and 1 to 80 parts by mass of basic copper carbonate with respect to 100 parts by mass of basic copper nitrate. Preferably, 2.5-60 mass parts is more preferable, and 5-50 mass parts is still more preferable.

  Other oxidizing agents include metal nitrate, ammonium nitrate, metal perchlorate, ammonium perchlorate, metal nitrite, metal chlorate, basic cobalt nitrate, basic zinc nitrate, basic manganese nitrate, etc. Can do.

  In the gas generant composition of the present invention, the content of the oxidizing agent is preferably 40 to 95% by mass, more preferably 45 to 90% by mass, and still more preferably 50 to 85% by mass.

  The gas generant composition of the present invention can further contain aluminum hydroxide. By containing aluminum hydroxide, the amount of nitrogen oxides, carbon monoxide and the like in the generated gas can be reduced, which is preferable.

  In the gas generant composition of the present invention, the content of aluminum hydroxide is preferably 0.1 to 20% by mass, more preferably 0.2 to 15% by mass, and still more preferably 1 to 10% by mass.

  The gas generant composition of the present invention can further contain a binder. Examples of the binder include carboxymethylcellulose, carboxymethylcellulose sodium salt, carboxymethylcellulose potassium salt, carboxymethylcellulose ammonium salt, cellulose acetate, cellulose acetate butyrate, methylcellulose, ethylcellulose, hydroxyethylcellulose, ethylhydroxyethylcellulose, hydroxypropylcellulose, carboxymethylethylcellulose, fine Crystalline cellulose, polyacrylamide, polyacrylamide amination, polyacryl hydrazide, acrylamide / metal acrylate copolymer, polyacrylamide / polyacrylate copolymer, polyvinyl alcohol, acrylic rubber, guar gum, starch, Examples include silicone.

  In the gas generant composition of the present invention, the binder content is preferably 0.5 to 30% by mass, more preferably 1 to 20% by mass, and still more preferably 2 to 10% by mass.

  The gas generant composition of this invention can contain the well-known additive mix | blended with a gas generant composition as needed. Known additives include copper oxide, iron oxide, zinc oxide, cobalt oxide, manganese oxide, molybdenum oxide, nickel oxide, bismuth oxide, silica, metal oxides including alumina; cobalt hydroxide, iron hydroxide, hydroxide Metal hydroxide such as magnesium (except aluminum hydroxide); Cobalt carbonate, calcium carbonate, basic zinc carbonate, metal carbonate including basic copper carbonate or basic metal carbonate; acid clay, kaolin, talc , Bentonite, diatomaceous earth, hydrotalcite-containing metal oxides or hydroxide composite compounds; metal silicates such as sodium silicate, mica molybdate, cobalt molybdate, ammonium molybdate, silicone, molybdenum disulfide, Calcium stearate, silicon nitride, silicon carbide, boric acid, metaboric acid, anhydrous boric acid It can be mentioned.

  The gas generant composition of the present invention can be molded into a desired shape, and can be formed into a single-hole cylindrical, porous cylindrical, or pellet-shaped molded body. These molded products are prepared by adding water or an organic solvent to the gas generating composition, mixing and extruding (single-hole cylindrical or porous cylindrical molded body) or compression molding using a tableting machine or the like. It can be manufactured by (pellet-shaped molded body).

  The gas generant composition of the present invention or a molded product obtained therefrom includes, for example, an air bag inflator for various vehicles, an air bag inflator for a passenger seat, a side air bag inflator, an inflatable curtain inflator, and a knee bolster. It can be applied to an inflator for an inflator, an inflator for an inflatable seat belt, an inflator for a tubular system, and a gas generator for a pretensioner.

  The inflator using the gas generant composition of the present invention or a molded product obtained therefrom is a hybrid in which the gas supply is a pyrotype only from the gas generant, and a compressed gas such as argon and the gas generant. Any type.

  Furthermore, the gas generant composition of the present invention or a molded product obtained therefrom can be used as an igniting agent called an enhancer (or booster) for transmitting the energy of the detonator or squib to the gas generant.

  The measuring method in the following is as follows.

(1) Combustion test A gas generating agent that generates 0.9 mol of gas was sealed in a thick chamber having an inner diameter of 75 mm and an inner height of 28 mm. In the center of the thick chamber, there is an inner tube having a diameter of 20 mm, and 1.45 g of B / KNO ₃ additive and initiator are arranged in the inner tube. In addition, a plurality of nozzles having a diameter of 2 mm were opened on the peripheral wall of the thick chamber. By adjusting the number of the nozzles, the internal pressure of the thick chamber when burning at normal temperature (23 ° C.) was adjusted to around 12 MPa. The thick chamber was placed in a low temperature (−40 ° C.) atmosphere, and a current was passed through the initiator to ignite the gas generating agent. The ignition state at that time was determined according to the following criteria.
Good: The gas generating agent ignited within 10 ms after the initiator ignited.
Bad: The gas generating agent did not ignite even after 10 ms from the ignition of the initiator.

(2) Combustion temperature, generated gas efficiency This is based on theoretical calculations. In the generated gas efficiency, the unit mol / 100 g represents the number of moles of generated gas per 100 g of the composition.

(3) Combustion rate The powdery composition is filled on the die side of a predetermined mold, and is compressed and held at a pressure of 14.7 MPa for 5 seconds from the end surface on the heel side, then taken out, and the outer diameter is 9.6 mm. And formed into a cylindrical strand having a length of 12.70 mm. The molded body was dried at 110 ° C. for 16 hours, and then the strand density was calculated from the strand weight, strand diameter, and height. Furthermore, after applying “bond quick 30” manufactured by Konishi Co., Ltd., an epoxy resin chemical reaction adhesive on the side surface and one end surface of this cylindrical molded body, it is cured at room temperature for 2 hours or more and used as a sample.

  A cylindrical strand as a sample was placed in a SUS sealed bomb having an internal volume of 1 L, and pressure was stabilized to 6.86 MPa while the bomb was completely purged with nitrogen. Thereafter, a predetermined current was passed through the nichrome wire brought into contact with the end face of the strand, and the energy was ignited and burned. The time-dependent pressure behavior in the bomb is confirmed on the chart of the recorder, the elapsed time from the start of combustion to the pressure rise peak is confirmed from the scale on the chart, and the strand length before combustion is divided by this elapsed time. The calculated value was taken as the burning rate.

(4) Gas concentration measurement method Cylindrical strands (mass 2.00 g) prepared by the same method as (3) above were placed in a 1 L internal SUS sealed bomb, and the inside of the bomb was completely replaced with nitrogen. The pressure was stabilized up to 7 MPa. Thereafter, a predetermined current was passed through the nichrome wire brought into contact with the end face of the strand, and the ignition energy was burned and burned by the fusing energy. After waiting 60 seconds and the gas in the bomb becomes uniform, sampling is performed by connecting the opening part of the tedlar bag with a predetermined stopper to the bomb gas discharge part, and introducing the combustion gas in the bomb. ) made of a gas detecting tube (NO ₂ and NO detection: No.10, NH ₃ detection: No.3L, CO detection: by _Nanba1L), was measured _{NO 2, NO, NH 3,} CO concentration .

The components of the gas generant composition used below are as follows:
Fine melamine: particle diameter (D ₅₀ ) measured by laser scattering method is 35 μm or less Melamine: particle diameter (D ₅₀ ) measured by laser scattering method is 35-50 μm GN: guanidine nitrate BCN: basic copper nitrate BCC: Basic copper carbonate CMCNa: Carboxymethylcellulose sodium salt Example 1 and Comparative Example 1
A combustion test was performed on the gas generant composition having the composition shown in Table 1. The results are shown in Table 1.

Examples 2-4
Each measurement was performed on the gas generant composition having the composition shown in Table 2. The results are shown in Table 2.

Examples 5-8
Each measurement was performed on the gas generant composition having the composition shown in Table 3. The results are shown in Table 3.

Examples 9-12
Each measurement was performed on the gas generant composition having the composition shown in Table 4. The results are shown in Table 4.

Examples 13-17
Each measurement was performed on the gas generant composition having the composition shown in Table 5. The results are shown in Table 5.

Examples 18-24
Each measurement was performed on the gas generant composition having the composition shown in Table 6. The results are shown in Table 6.

Claims (4)

A gas generant composition containing a fuel and an oxidant, and containing melamine having a particle size (D50) measured by a laser scattering method of 35 μm or less as a fuel , wherein the oxidant is basic copper nitrate and / or Alternatively, a gas generating composition containing basic copper carbonate .   The gas generant composition according to claim 1, further comprising guanidine nitrate as a fuel. As an oxidizing agent, a basic copper nitrate and basic copper carbonate in combination, the ratio of the case is, according to claim 1 or 2 wherein the basic copper carbonate is 1 to 100 parts by mass with respect to basic copper nitrate 100 parts by Gas generant composition. Furthermore, the gas generating composition in any one of Claims 1-3 containing aluminum hydroxide.