WO2010134466A1

WO2010134466A1 - Gas generant composition

Info

Publication number: WO2010134466A1
Application number: PCT/JP2010/058154
Authority: WO
Inventors: 小林正治
Original assignee: ダイセル化学工業株式会社
Priority date: 2009-05-21
Filing date: 2010-05-14
Publication date: 2010-11-25
Also published as: EP2444383B1; EP2444383A1; JP5441497B2; CN102428056B; EP2444383A4; CN102428056A; US20120055593A1; JP2010269969A

Abstract

Disclosed is a gas generant composition containing a fuel and an oxidant, which can be used for an inflator for a vehicle airbag system, or the like. The gas generant composition is characterized in that the oxidant contains a basic copper carbonate, the basic copper carbonate content in the gas generant composition is more than 40% by mass but 60% by mass or less, and the following conditions (a)-(c) are satisfied. (a) The burning rate is not less than 7.0 mm/sec. (b) The gas generation efficiency is not less than 2.30 mol/100 g. (c) The amount of heat generated per 1 mole of the generated gas is not more than 100 kJ/mol.

Description

Gas generant composition

The present invention relates to a gas generant composition that can be used in an inflator for a vehicle airbag device or the like.

In recent years, in order to reduce the size and weight of inflators for vehicle airbag devices, which have been increasingly demanded, it is necessary to lower the combustion temperature of the gas generating agent. However, this may slow down the combustion rate or reduce the amount of gas generated. In order to improve it, a method of increasing the gas generating agent filled in the inflator is conceivable, but there arises a problem that the inflator, which is the original purpose, cannot be reduced in size and weight. In order to solve such a problem, it is desirable to use “a calorific value per mole of generated gas” as an index. Usually, it is desirable to realize an appropriate combustion rate and gas generation efficiency while realizing a calorific value per mol of generated gas of about 100 kJ / mol or less.

JP-A 2004-155645 includes basic copper nitrate, basic cobalt nitrate, basic zinc nitrate, basic manganese nitrate, basic iron nitrate, basic molybdenum nitrate, basic bismuth nitrate and A basic metal nitrate selected from basic cerium nitrate is described, and it is described that the calorific value can be suppressed by adding aluminum hydroxide.

JP-A 2001-220282 includes basic copper nitrate, basic cobalt nitrate, basic zinc nitrate, basic manganese nitrate, basic iron nitrate, basic molybdenum nitrate, basic bismuth nitrate and basic oxidants. It describes that a basic metal nitrate selected from cerium nitrate can be used.

JP-B 3907548 includes metal nitrate, ammonium nitrate, metal perchlorate, ammonium perchlorate, metal nitrite, metal chlorate, basic copper nitrate, basic cobalt nitrate, basic zinc nitrate, basic nitrate. An oxygen-containing oxidant selected from manganese is described.

JP-A 2006-76849 describes a gas generating composition in which the content of basic copper carbonate is more than 20% by weight and not more than 40% by weight. Since the amount is only 22.0% by weight, the effect when the content of basic copper carbonate is 30% by weight or more has not been confirmed.
Summary of the Invention

The present invention can reduce the calorific value per mole of generated gas without impairing the combustion rate and gas generation efficiency, which has not been sufficiently solved by the above-described prior art, and the amount of mist generated during combustion or harmful It is an object of the present invention to provide a gas generant composition that can be used for an inflator for a vehicle airbag device and the like that has no problem in gas concentration.

The present invention 1 is a gas generant composition containing a fuel and an oxidant, wherein the oxidant contains basic copper carbonate, and the content of the basic copper carbonate in the gas generant composition is 40% by mass. And a gas generant composition that satisfies the following requirements (a) to (c).
(A) Combustion rate is 7.0 mm / sec or more (b) Gas generation efficiency is 2.30 mol / 100 g or more (c) The calorific value per mol of generated gas is 100 kJ / mol or less.
Detailed Description of the Invention

The gas generant composition of the present invention can reduce the calorific value per mole of generated gas by using a predetermined range of basic copper carbonate without impairing the combustion rate and gas generation efficiency. Since there is no problem with the amount of mist generated during combustion and the concentration of harmful gases, it is useful for inflators for vehicle airbag devices and the like.

The present invention includes the following preferred embodiments 2 to 6.
2. The gas generant composition according to the present invention, wherein the content of the basic copper carbonate is 42 to 60% by mass.
3. The gas generating composition according to the present invention, wherein the oxidizing agent is a combination of basic copper carbonate and basic metal nitrate and / or nitrate, and the total content of the oxidizing agent is 50 to 80% by mass.
4). The gas generating composition according to the present invention, wherein the oxidizing agent is a combination of basic copper carbonate, basic copper nitrate and / or strontium nitrate, and the total content of the oxidizing agent is 50 to 80% by mass.
5). The gas generant composition according to the present invention, further containing a carboxymethyl cellulose salt as a binder.
6). The gas generant composition according to the present invention, further comprising aluminum hydroxide.

Examples of the gas generant composition of the present invention or a molded product obtained therefrom include, for example, an inflator for an air bag in a driver seat of various vehicles, an inflator for an air bag in a passenger seat, an inflator for a side air bag, an inflator for an inflatable curtain, 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 from the gas generator comprises a pyrotype in which the gas supply source is only the gas generant, and a hybrid in which both the compressed gas such as argon and the gas generant are used. Any type.

Furthermore, the gas generant composition of the present invention or a molded product obtained from the gas generant composition can also be used as an igniter called enhancer or booster for transmitting the energy of the detonator or squib to the gas generant.

<Fuel>
As the fuel used in the present invention, a known fuel for the gas generant composition can be used, and examples thereof include one or more selected from guanidines, tetrazoles, triazines, purines, or amino acid derivatives.

The guanidine is preferably guanidine nitrate, nitroguanidine, guanylurea dinitramide or the like. The tetrazole is preferably 5-aminotetrazole, bitetrazole diammonium salt or the like. The triazines are preferably melamine, melamine cyanurate, melamine nitrate, melamine perchlorate, trihydrazinotriazine, melamine nitro compounds, and the like. The purines are preferably 8-azaguanine and the like. The amino acid derivative is preferably glycine or the like.

The fuel used in the present invention may be a mixture of two or more types as necessary. A mixture of two or more guanidines or a mixture of guanidines and other types is preferred. For example, in the case of guanidine nitrate alone, the calorific value can be made relatively low, but there are problems with the combustion rate and ignitability. On the other hand, in the case of nitroguanidine alone, there is no problem in combustion speed and ignitability, but there is a problem that gas generation efficiency is relatively low. In response to these problems, by mixing guanidine nitrate and nitroguanidine, it is possible to obtain a fuel in which the drawbacks are overcome while taking advantage of both.

The content of the fuel used in the present invention is preferably 20 to 60% by mass, more preferably 25 to 55% by mass, and further preferably 30 to 50% by mass in the gas generant composition.

<Oxidizing agent>
The oxidizing agent used in the present invention contains basic copper carbonate. The content of basic copper carbonate is more than 40% by mass and not more than 60% by mass, preferably 42 to 60% by mass, in the gas generant composition. When it is 40% by mass or less, the effect of reducing the calorific value is insufficient, and when it exceeds 60% by mass, the ignitability is impaired.

The average particle diameter of basic copper carbonate is preferably 5 μm or less, more preferably 3 μm or less, and even more preferably 1 μm or less. When the average particle size is large, the combustion rate is slow and the ignitability is deteriorated. The average particle size was measured by a particle size distribution method using laser scattered light. The measurement was carried out using a MICROTRAC, Model No. 9320-X100 particle size measuring device manufactured by Neede + Northrop Company, after dispersing the sample in ion-exchanged water and irradiating 50 watts of ultrasonic waves in 60 seconds. The 50% cumulative value of the particle volume was determined, and the average value of two measurements was taken as the average particle diameter.

The oxidizing agent can further contain a known oxidizing agent, and is selected from nitrate, basic metal nitrate, ammonium nitrate, metal perchlorate, ammonium perchlorate, metal nitrite, metal chlorate and the like. More than one type of oxidizing agent can be included.

The basic metal nitrate is selected from basic copper nitrate, basic cobalt nitrate, basic zinc nitrate, basic manganese nitrate, basic iron nitrate, basic molybdenum nitrate, basic bismuth nitrate, basic cerium nitrate, etc. One or more types may be mentioned, and basic copper nitrate is preferable.

Examples of the nitrate include one or more selected from alkaline metal nitrates such as potassium nitrate and sodium nitrate and alkaline earth metal nitrates such as strontium nitrate, and strontium nitrate is preferable.

The total content of the oxidizing agent used in the present invention is preferably 50 to 80% by mass, more preferably 50 to 75% by mass, and further preferably 50 to 70% by mass in the gas generant composition.

<Binder>
The gas generant composition of this invention can contain what is well-known as a binder of a gas generant composition as needed. For example, carboxymethylcellulose (CMC), carboxymethylcellulose sodium salt (CMCNa), carboxymethylcellulose potassium salt (CMCK), carboxymethylcellulose ammonium salt (CMCNH ₄ ), cellulose acetate, cellulose acetate butyrate (CAB), methylcellulose (MC), ethylcellulose (EC), hydroxyethylcellulose (HEC), ethylhydroxyethylcellulose (EHEC), hydroxypropylcellulose (HPC), carboxymethylethylcellulose (CMEC), microcrystalline cellulose, polyacrylamide, polyacrylamide amination, polyacrylhydrazide, acrylamide・ Acrylic acid metal salt copolymer, polyacrylamide ・ polyacrylic acid S Copolymers of Le compounds, polyvinyl alcohol (PVA), acrylic rubber, guar gum, starch, one or more can be mentioned selected from silicone.

As the binder, water-soluble cellulose derivatives (CMC, CMCNa, CMCK, CMCNH ₄ , MC, EC, HEC, EHEC, HPC, CMEC), microcrystalline cellulose, PVA, guar gum, and starch which are water-soluble binders are preferable. Among these, a water-soluble cellulose derivative is preferable, CMC, CMCNa, CMCK, and CMCNH ₄ are more preferable, and CMCNa is still more preferable.

The content of the binder used in the present invention is preferably 0.5 to 30 parts by mass, more preferably 1 to 20 parts by mass, and further preferably 2 to 15 parts by mass with respect to 100 parts by mass in total of the fuel and the oxidant.

<Additives>
The gas generant composition of the present invention can contain, as necessary, known additives such as a combustion catalyst, an endothermic agent, a slag forming agent, and a lubricant as additives for the gas generant composition. Known additives include copper oxide, iron oxide, zinc oxide, cobalt oxide, manganese oxide, molybdenum oxide, nickel oxide, bismuth oxide, silica, metal oxides including alumina; aluminum hydroxide, cobalt hydroxide, hydroxide Metal hydroxide such as iron and magnesium hydroxide; metal carbonate or basic metal carbonate containing cobalt carbonate, calcium carbonate, basic zinc carbonate; acid clay, kaolin, talc, bentonite, diatomaceous earth, hydrotalcite Metal oxide or hydroxide composite compound containing; metal diacid salts such as ammonium dihydrogen phosphate, ammonium polyphosphate, sodium silicate, mica molybdate, cobalt molybdate, ammonium molybdate, silicone, molybdenum disulfide, Calcium stearate, silicon nitride, silicon carbide, boric acid, On the other hand acid, and boric anhydride and the like.

The content of the additive used in the present invention is not limited so long as it has a great influence on the calorific value, gas generation efficiency, and combustion rate, which are the effects of the present invention. 0.5 to 30 parts by mass is preferable, 1 to 25 parts by mass is more preferable, and 2 to 20 parts by mass is even more preferable.

The gas generant composition of the present invention satisfies all of the following requirements (a) to (c), and preferably further satisfies the requirement (d).
(A) Combustion rate is 7.0 mm / second or more, preferably 7.4 mm / second or more (b) Gas generation efficiency is 2.30 mol / 100 g or more, preferably 2.37 mol / 100 g or more (c) 1 mol of generated gas The amount of heat generated per unit is 100 kJ / mol or less, preferably 90 kJ / mol or less. (D) The combustion temperature is preferably 2000 K or less, more preferably 1800 K or less.

The composition of the present invention can be molded into a desired shape, and can be formed into a columnar shape, a single-hole columnar shape, a porous columnar shape, or a pellet shape.

These molded products are prepared by adding water or an organic solvent to the composition, mixing and extrusion molding (cylindrical, single-hole cylindrical, porous cylindrical molded body), or compression molding using a tableting machine or the like. It can be manufactured by (pellet-shaped molded body).
Example

<Measurement of burning rate>
[Method for creating measurement strand]
Each component of the gas generant composition was sufficiently mixed at the ratio shown in Table 1, and then 30 g was weighed. 6 g of water was added thereto and mixed in an antistatic vinyl bag for 5 minutes or more. The resulting mass was made into small pieces, dried at 110 ° C. for 2 hours, and then pulverized in a mortar to obtain a powder. 1.7 to 2.2 g of this powder was charged into a mold, and a pressure of about 220 MPa (2250 kgf / cm ² ) was applied with a hydraulic pump and held for 5 seconds, and then a cylindrical strand (outer diameter 9.55 mm, length) 12.70 mm) was obtained.

〔Measuring method〕
The measurement strand obtained above was allowed to stand at 110 ° C. for 16 hours to remove moisture, and then the epoxy resin adhesive “Bond Quick 30” was applied twice to the side and one side so as to ignite and burn only from the end face. Applied. It was placed in a SUS sealed bomb (internal volume 1 L) and pressurized to 7 MPa while the inside of the bomb was replaced with nitrogen. After the internal pressure of the bomb was stabilized, a voltage of 12 V was applied to the nichrome wire brought into contact with the end face of the measurement strand, and ignition and combustion were performed by the fusing energy. The value calculated by dividing the length of the measurement strand before combustion by the elapsed time from the start of combustion to the pressure rise peak was taken as the burning rate.
[Calculation of gas generation efficiency, calorific value per mol of generated gas, and combustion temperature]
The gas generation efficiency, the calorific value per mole of the generated gas, and the combustion temperature were calculated by simulation using a thermochemical equilibrium calculation program “NEWWP P”.

[Method for measuring friction sensitivity and drop sensitivity]
About each powder raw material which comprises a gas generant composition, it measured so that the mass of a gas generant composition might be 1 g, and it mixed sufficiently. Friction sensitivity and drop sensitivity were measured for the obtained powder samples based on the explosives performance test method of Japanese Industrial Standard (JIS) K4810-1979.

[Method of measuring decomposition temperature]
Using the same gas generant composition as the method for measuring the friction sensitivity and the drop sensitivity, thermal mass measurement (Thermogravimetry) was performed using a thermobalance (TGDTA6300 manufactured by Seiko Epson Corporation), and the temperature at which mass reduction was started was defined as the decomposition temperature. .

[Measurement method of exhaust gas concentration]
The measurement strand (outer diameter 9.55 mm, mass 2.00 g) obtained by the same method as described above was left at 110 ° C. for 16 hours to remove moisture, and then the inside of the SUS sealed bomb (internal volume 1 L) The pressure was increased to 7 MPa while the inside of the bomb was replaced with nitrogen. After the pressure inside the bomb was stabilized, a predetermined current was applied to the nichrome wire brought into contact with the end face of the measurement strand, and ignition and combustion were performed by the fusing energy. After the elapse of 60 seconds, the generated exhaust gas is collected, and a gas detector (GV-100S manufactured by Gastec) and a gas detector tube (No.10: manufactured by Gastech Co., No., No. 3L and 3M: NH ₃ detected) The gas concentration was measured by No. 1L: for CO).
Examples and Comparative Examples

Each measurement shown in Table 1 was performed for each composition shown in Table 1.

GN: Guanidine nitrate
NQ: Nitroguanidine
GUDN: Guanylurea dinitramide
Mel: Melamine
MC: Melamine cyanurate
BCC: Basic copper carbonate (average particle size approx. 1μm)
BCN: Basic copper nitrate
SrN: Strontium nitrate
CMCNa: Carboxymethylcellulose sodium salt
Al (OH) ₃ : Aluminum hydroxide

In all of Examples 1 to 23, although a large amount of basic copper carbonate having a large endothermic effect (greater than 40% by mass and less than 60% by mass) is used, a practical burning rate (7.0 mm) is used. It is recognized that the calorific value per mole of the generated gas is sufficiently suppressed (100 kJ / mol or less) without impairing the gas generation efficiency (2.30 mol / 100 g or more). On the other hand, in any of Comparative Examples 1 to 8, it is considered that either the gas generation efficiency or the combustion rate is insufficient and there is a problem in practicality.

Each measurement shown in Table 2 was performed for each composition shown in Table 2.

From Table 2, the friction sensitivity is JIS grade, the safest grade 7, or the grade 6 that can be handled safely enough. In addition, the drop sensitivity is the safest grade 8 in the JIS grade. Furthermore, the decomposition start temperature is 150 ° C. or higher, which is a decomposition start temperature region that can withstand welding during manufacture of the inflator. From the above, it is recognized that all have low risk, can be manufactured safely, and have practicality.

Each measurement shown in Table 3 was performed for each composition shown in Table 3.

From Table 3, it is recognized that there is no problem in the exhaust gas concentrations of NO, NH ₃ and CO which are harmful gases.

Claims

A gas generant composition containing a fuel and an oxidant, wherein the oxidant contains basic copper carbonate, and the content of the basic copper carbonate in the gas generant composition exceeds 40% by mass and 60% by mass A gas generating composition that satisfies the following requirements (a) to (c):
(A) Combustion rate is 7.0 mm / second or more (b) Gas generation efficiency is 2.30 mol / 100 g or more (c) Heat generation per mole of generated gas is 100 kJ / mol or less
The gas generating composition according to claim 1, wherein the content of the basic copper carbonate is 42 to 60% by mass.
The gas generating composition according to claim 1 or 2, wherein the oxidizing agent is a combination of basic copper carbonate and basic metal nitrate and / or nitrate, and the total content of the oxidizing agent is 50 to 80% by mass.
The gas generating composition according to claim 1 or 2, wherein the oxidizing agent is a combination of basic copper carbonate, basic copper nitrate and / or strontium nitrate, and the total content of the oxidizing agent is 50 to 80% by mass.
The gas generant composition according to any one of claims 1 to 4, further comprising a carboxymethyl cellulose salt as a binder.
The gas generating composition according to any one of claims 1 to 5, further comprising aluminum hydroxide.