JP4575036B2 - Gas generant composition - Google Patents

Description

  The present invention relates to a gas generating agent used for a gas generator for an air bag.

  A gas generating agent used for a gas generator for an air bag is generally composed of a fuel, an oxidant, a binder, and various additives.

  Conventionally, water-soluble cellulose binders (starch, carboxymethyl cellulose, guar gum, etc.) and polyvinyl alcohol are often used as binders because of their good moldability, but most of the fuels and oxidants are water-soluble. Therefore, there is a problem that they are dissolved in the mixing stage, recrystallized after drying, the desired particle size cannot be maintained, and the designed combustion performance cannot be obtained.

  In addition, when cellulosic polymers (starch, carboxymethyl cellulose, guar gum, cellulose acetate butyrate, etc.) are used as a binder for the gas generating agent, these cellulosic polymers generate gas when combined with ammonium nitrate, which is widely used as a fuel. There is a problem of greatly reducing the heat resistance of the agent.

Furthermore, HTPB (Hydroxyl Terminated Polybutadiene) and GAP (Glycidyl Azide Polymer), which are excellent in their own combustion performance, are also known as organic solvent-based binders. Since a recovery process is required, there is a problem in that the manufacturing cost is increased.
WO98 / 9927 USP 5,997,666 WO98 / 23558 JP-A-11-217289 Special table hei 9-501388

  The gas generant composition of Patent Document 1 uses cellulose acetate butyrate as a binder, the gas generant composition of Patent Document 2 uses polyvinyl alcohol as a binder, and the gas generant composition of Patent Document 3. The product uses HTPB and GAP as binders, and each has problems in the above-described prior art.

  Patent Document 4 discloses a hybrid inflator using a propellant including a secondary explosive and a binder system. This propellant has a composition for increasing the gas combustion temperature and realizing the function of breaking the burst disk of the hybrid gas generator in the early stage of combustion. Therefore, the combustion of propellant alone can only be achieved as an inflator exhaust gas by burning in the vaporization stage after the initial combustion of the propellant with a predetermined amount of oxygen in the coexisting high-pressure gas. It is not possible to clean the combustion gas by itself.

  Patent Document 5 also exemplifies polycaprolactam as a binder of a propellant formulation containing a high energy binder. However, in applications such as the propellant formulation, a particularly advanced exhaust gas cleaning is not necessary. Since the composition is not based on the purpose, it is difficult to highly clean the combustion gas with the combination of the disclosed high energy binder, dinitroamide oxidizer, reactive metal, and polyfunctional compound.

  The present invention can obtain the combustion performance as designed, does not react with ammonium nitrate, has a high slag forming ability, can reduce the amount of jetted mist (meaning a metal component in the gas generating agent), and can reduce the combustion gas. It is an object to provide a gas generating agent that can be cleaned.

  As a means for solving the problem, the present invention includes a fuel, an oxidant, and a binder, and the binder is one or more selected from polylactone compounds. Provided is a gas generant composition in which the concentrations of ammonia and nitrogen dioxide are substantially 0 ppm.

  In the present invention, “the concentration of ammonia and nitrogen dioxide is substantially 0 ppm as a result of exhaust gas analysis after combustion” means that the measurement result by the gas detector tube is in the range of 0 to X ppm. Here, X indicates the upper limit value of the error range of the gas detector tube.

  The gas generant composition of the present invention, when mixing a fuel, an oxidant and a polylactone compound as a binder, a small amount of an organic solvent is added or mixed, or a polylactone compound which is heat-melted without a solvent is added and mixed. In addition, since it can be further molded, the particle sizes of the fuel and the oxidant can be maintained at the desired particle sizes, so that a desired burning rate can be obtained.

Since the gas generant composition of the present invention contains a polylactone compound as a binder, the generation amount of NO ₂ , NO, NH ₃ , CO is reduced, the combustion gas becomes clean, and the slag forming ability Therefore, the amount of mist ejected can be reduced.

  In the gas generant composition of the present invention, since the polylactone compound as a binder does not react with ammonium nitrate which is widely used as a fuel, even when used in combination with ammonium nitrate, the heat resistance of the obtained composition is impaired. Does not occur.

  The gas generant composition of the present invention contains one or more selected from a polylactone compound as a fuel, an oxidant, and a binder, and is characterized by using a polylactone compound as a binder. It is what you have.

  Polylactone compounds can be dissolved in organic solvents such as acetone, toluene, xylene, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, isophorone, cellosolve acetate, Solvesso 100 (ExxonMobil Corp.) and trichlene. Since it can also be thermally melted with a solvent, the gas generant composition can be produced in a non-aqueous system. For this reason, the problem of changing the particle size due to dissolution of water-soluble fuel and oxidizer in water and recrystallization, as in the case of using water in the manufacturing stage, is maintained, and the desired particle size is maintained. Therefore, the designed combustion performance (burning rate) can be obtained. The combustion speed is obtained by the method described in the embodiment, but can be determined empirically, so that the combustion speed can be set to a substantially desired value (design value) in advance.

  Examples of polylactone compounds include ε-caprolactone (for example, trade name “Placcel M” sold by Daicel Chemical Industries, Ltd.), 2-methyl and 4-methyl, or 4,4′-dimethyl. And those obtained using a monomer selected from methylation (ε-caprolactone), δ-valerolactone, methylation (δ-valerolactone), β-propiolactone, and the like, Polyε-caprolactone obtained using ε-caprolactone is preferred.

  These monomers may be used alone, or may be used by copolymerizing a plurality of types of monomers, may be copolymerized with other monomers such as polyol or polycarboxylic acid component, or polylactone compounds. And other polymer compounds may be used.

  Other monomers include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, 1,6-hexanediol, and other polyols, glycerin, polyglycerin, triglycerin, and the like. Polyols such as methylolpropane, polytrimethylolpropane, pentaerythritol, polypentaerythritol, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, citric acid, malic acid, tartaric acid, glucaric acid Dicarboxylic acids such as are preferred.

  Examples of other polymer compounds that can be mixed as the polymer alloy include polyacrylic compounds, polyacetals, urea resins, melamine resins, and ketone resins.

  Polyε-caprolactone can be produced by a known method, for example, the method described in the upper left column of page 3 of JP-A No. 62-246927.

  The polylactone compound preferably has a weight average molecular weight in the range of 100 to 100,000, more preferably 500 to 90,000, still more preferably 1000 to 80,000. The weight average molecular weight is obtained by GPC by standard PMMA conversion.

  Examples of the poly-ε-caprolactone compound include trade name “Placcel 205” (weight average molecular weight 530), trade name “Placcel 208” (weight average molecular weight 830), and trade name “Placcel 210” manufactured by Daicel Chemical Industries, Ltd. (Weight average molecular weight 1000), trade name “Placcel 212” (weight average molecular weight 1250), trade name “Placcel 220” (weight average molecular weight 2000), trade name “Placcel 230” (weight average molecular weight 3000), trade name “Placcel” 240 "(weight average molecular weight 4000), trade name" Placcel HIP "(weight average molecular weight 10,000), trade name" Placcel H5 "(weight average molecular weight 50,000), trade name Plaxel H7 (weight average molecular weight 70,000) Etc.) can be used.

  In addition, as long as the problem of the present invention is solved and the effects of the present invention are obtained, other binders can be used in combination, but even in that case, the content of the polylactone compound in the binder is preferably 50% by mass or more, more preferably 70% by mass or more, and still more preferably 80% by mass or more. However, substantially only a polylactone compound is used as a binder. It is particularly preferred to include very small amounts of other binders that do not have any effect.

  The fuel is not particularly limited, and examples thereof include those used in known gas generating agents. Among them, nitrogen-containing organic compounds are preferable.

  As the nitrogen-containing compound, one or more compounds selected from guanidine nitrate, nitroguanidine, 5-aminotetrazole, dicyandiamide, azodicarbonamide, ammonium nitrate, melamine, and glycine can be used. In addition, di- or triaminoguanidine nitrate, guanidine carbonate, nitroaminoguanidine nitrate, bitetazole derivatives such as bitetazole diammonium salt, triazole derivatives such as 4-aminotriazole, triazine derivatives such as trihydrazinotriazine, oxamide, shu Ammonium acid, hydrazodicarbonamide and the like can also be used.

  Among these, guanidine nitrate, nitroguanidine, 5-aminotetrazole, dicyandiamide and ammonium nitrate are preferable.

  The oxidizing agent is not particularly limited, and examples thereof include those used for known gas generating agents. Among them, inorganic oxidizing agents are preferable.

  As the inorganic oxidizing agent, one or more selected from basic copper nitrate, sodium nitrate, potassium nitrate, strontium nitrate, sodium perchlorate, potassium perchlorate, and strontium perchlorate can be used. . Among these, basic copper nitrate, potassium nitrate, strontium nitrate and potassium perchlorate are preferable.

  In the gas generant composition of the present invention, various additives blended with known gas generants can be blended as necessary. Additives include metal oxides such as copper oxide, iron oxide, zinc oxide, cobalt oxide, manganese oxide, molybdenum oxide, nickel oxide, bismuth oxide, silica, and alumina; cobalt carbonate, calcium carbonate, basic zinc carbonate, base Metal carbonates such as basic copper carbonate or basic metal carbonates; complex compounds of metal oxides or hydroxides such as acid clay, kaolin, talc, bentonite, diatomaceous earth, hydrotalcite; sodium silicate, mycamolybdic acid Metal salts such as salts, cobalt molybdate, and ammonium molybdate; one or more selected from molybdenum disulfide, calcium stearate, silicon nitride, and silicon carbide can be used.

  The content ratio of each component in the gas generant composition of the present invention can be selected from the following ranges.

  The fuel is preferably 5 to 80% by mass, more preferably 10 to 70% by mass, and still more preferably 20 to 60% by mass in the composition.

  In the composition, the oxidizing agent is preferably 10 to 90% by mass, more preferably 20 to 80% by mass, and still more preferably 30 to 60% by mass.

  In order to solve the problems of the present invention and obtain the effects of the present invention, the polylactone compound as a binder is preferably 0.1 to 30% by mass, more preferably 0.5 to 20% by mass in the composition. More preferably, it is 3 to 10% by mass.

  In addition, when an additive is blended as necessary, it may be blended in an amount of 0.01 to 20 parts by mass with respect to a total of 100 parts by mass of the fuel, the oxidant, and the binder.

  The gas generant composition of the present invention can be formed into a desired molded body such as a disk, a column, a single-hole column, a porous column, or a pellet.

  Since the gas generant composition of the present invention uses a polylactone compound as a binder, each component can be mixed and molded in a non-aqueous system as described in the Examples. As a molding method, an extrusion molding method (single-hole columnar or porous columnar molded body) or a compression molding method using a tableting machine (pellet-shaped molded body) can be applied. The method described in Japanese Patent No. 342091 can also be applied.

  The gas generating composition of the present invention includes, for example, an air bag inflator (gas generator) for a driver's seat of various vehicles, an air bag inflator, a side air bag inflator, an inflatable curtain inflator, and a knee bolster. The present invention can be applied to inflators, inflators for inflatable seat belts, inflators for tubular systems, and inflators for pretensioners.

  The gas generant composition of the present invention can be used as a gas generant composition for an inflator (gas generator), and an enhancer agent (or an agent for transmitting energy of a detonator or a squib to the gas generant composition (or It can also be used as an igniter called a booster.

  The measuring method in an Example and a comparative example is shown. In the following, “part” means “part by mass”.

(1) Preparation method of cylindrical strands Powders of compositions of Examples and Comparative Examples (mixed powder for molding. Examples 1 to 3 and Comparative Example 2 are non-aqueous as shown in Table 1) are given gold. The mold was filled into the mortar side, compressed from the end face on the heel side with a hydraulic pump at a pressure of 14.7 MPa for 5 seconds, taken out, and molded into a cylindrical strand having an outer diameter of 9.55 mm and a length of 12.70 mm. After applying “Bond Quick 30” manufactured by Konishi Co., Ltd., an epoxy resin-based chemical reaction adhesive on the side of this cylindrical molded body, it is cured at 110 ° C. for 16 hours, and does not ignite from the side, but ignites and burns only from the end surface. Samples that were made to perform (single-surface moving combustion) were used.

(2) Measuring method of burning rate The cylindrical strand used as a sample was installed in a 1 L SUS sealed bomb, and the pressure was stabilized to 7 MPa while completely replacing the inside of the bomb with nitrogen. After that, a predetermined current was passed through the nichrome wire brought into contact with the end face of the strand, and ignition and combustion were performed by the fusing energy. 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.

(3) Gas concentration measurement method Cylindrical strand (mass 2.00 g) as a sample is placed in a 1 L SUS sealed bomb and pressurized to 7 MPa while the bomb is completely purged with nitrogen. Stabilized. After that, a predetermined current was passed through the nichrome wire brought into contact with the end face of the strand, and ignition and combustion were performed by the fusing energy. After waiting 60 seconds and the gas in the bomb becomes uniform, connect the opening part of the tedlar bag with a predetermined stopper to the bomb gas discharge part and sample by transferring the combustion gas in the bomb. By using a gas detector gas detector tube (for NO ₂ and NO detection: No. 10, for NH ₃ detection: No, 3L, for CO detection: No, 1L) using a detector GV-100S, NO ₂ , NO, NH ₃ and CO concentrations were measured.

(4) Mass of recovered residue After completion of the above “(3) Gas concentration measurement method” test, the internal state of the bomb was visually observed and the internal residue was recovered and dried at 110 ° C. for 16 hours. The mass of was measured.

(5) Mass reduction rate The columnar strand (mass 2.00 g) used as a sample is left to stand at 110 degreeC for 400 hours in a thermostat, Then, it calculates | requires from following Formula.
Mass reduction rate (%) = (mass before test−mass after test) × 100 / mass before test.

(6) Weight average molecular weight by GPC It calculated | required by standard PMMA conversion. Showa Denko Co., Ltd. Shodex GPC HFIP-800P, HFIP-805P, HFIP-804P, HFIP-803P was used as the column, Shimadzu RID-6A was used as the detector, and HFIP was used as the eluent. The measurement was performed at a temperature of 50 ° C. and a flow rate of 1.0 ml / min.

Example 1
42.44 parts of guanidine nitrate, 30.76 parts of ammonium nitrate, and 21.80 parts of potassium perchlorate were rubbed twice through a SUS sieve having a mesh size of 300 μm to prepare particles, which were mixed to obtain a mixed powder.

  As a polylactone compound, a product name “Placcel 240” (weight average molecular weight 4000) 5 parts manufactured by Daicel Chemical Industries, Ltd. was mixed with 40 parts of acetone and dissolved while heating at 60 ° C. Added to 95 parts of the mixed powder and mixed well. Then, after drying at 110 degreeC for 1 hour and obtaining the composition of this invention, it shape | molded into the cylindrical strand further by said method. The measurement results are shown in Table 1.

Example 2
Example using 51.35 parts of guanidine nitrate, 43.65 parts of potassium perchlorate, and 5 parts of the trade name “Placcel HIP” (weight average molecular weight 10,000) manufactured by Daicel Chemical Industries, Ltd. as a polylactone compound. After obtaining the composition of the present invention in the same manner as in No. 1, it was further molded into a cylindrical strand by the above method. The measurement results are shown in Table 1.

Example 3
42.44 parts of guanidine nitrate and 21.80 parts of potassium perchlorate were rubbed twice through a SUS sieve having a mesh size of 300 μm to prepare grains, and mixed to obtain a mixed powder.

  As a polylactone-based compound, a product name "Placcel H5" (weight average molecular weight 50,000) manufactured by Daicel Chemical Industries, Ltd. dissolved in 80 parts while being heated to 80 ° C is added to 95 parts of the mixed powder. Then, after thoroughly mixing, dried at 110 ° C. for 1 hour to obtain the composition of the present invention, and further molded into a cylindrical strand by the above method. The measurement results are shown in Table 1.

Comparative Example 1
After rubbing 42.44 parts of guanidine nitrate, 28.36 parts of ammonium nitrate and 18.10 parts of potassium perchlorate twice through a 300 μm mesh SUS sieve, the particles were aligned and mixed to obtain a composition. Molded into a cylindrical strand by the above method. The measurement results are shown in Table 1.

Comparative Example 2
Rub 42.44 parts of guanidine nitrate, 30.76 parts of ammonium nitrate, 21.80 parts of potassium perchlorate, and 5.00 parts of carboxymethyl cellulose through a 300 μm mesh SUS screen twice to prepare and mix the grains. After obtaining the product, it was further molded into a cylindrical strand by the above method. The measurement results are shown in Table 1.

  The burning rates of Examples 1 to 3 were similar to the initial design values. This is because in the mixing stage, acetone is added or mixed, or a polylactone compound that has been heat-melted without solvent is added and mixed, and then molded, so that the raw material particle size (screening particle size) of the fuel and oxidant is maintained. It means that Even when acetone is used, the solvent recovery and removal operation is easier than when an organic solvent is used as a binder.

  As apparent from the residue masses of Examples 1 and 2, since the slag forming ability is high, the amount of mist ejected can be reduced.

As is apparent from the comparison of the mass reduction ratios of Example 1 and Comparative Examples 1 and 2, Example 1 was excellent in heat resistance despite containing ammonium nitrate.

Claims (4)

A gas generant composition containing a fuel, an oxidant, and a binder ,
The binder Ri one or more of what Der selected from polylactone compound,
The fuel is one or more nitrogen-containing organic compounds selected from guanidine nitrate, nitroguanidine, 5-aminotetrazole, dicyandiamide, azodicarbonamide, ammonium nitrate, melamine, and glycine;
A gas generating composition for use in an air bag gas generator, wherein the concentration of ammonia and nitrogen dioxide is substantially 0 ppm as a result of exhaust gas analysis after combustion. The gas generant composition used for a gas generator for an air bag according to claim 1, wherein the polylactone compound has a weight average molecular weight of 100 to 100,000. The gas generant composition used for a gas generator for an air bag according to claim 1 or 2, wherein the polylactone compound is polyε-caprolactone . Inorganic oxidizing agents, basic copper nitrate, sodium nitrate, potassium nitrate, strontium nitrate, sodium perchlorate, potassium perchlorate, claim 1-3 is from the perchlorate strontium least one selected gas generating composition for use in a gas generator for an air bag according to any one of.