DE102005044604A1 - Heat stable gas-forming agent for use in externally-installed airbag systems on vehicles especially comprises a propellant and an oxidation agent - Google Patents

Abstract

A gas-forming agent for a gas generator in an airbag system installed externally of a vehicle cabin for protection of one individual in a collision shows a weight loss of less than 1% after 400 hours storage in a sealed system at 130[deg]C.

Description

technical area

The The invention relates to a gas generating agent for a Gas generator used in an airbag system to protect a single Person who crashes into a vehicle.

technical background

In addition to Airbag systems for protection The occupants of an automobile are recently anxious to have an airbag system to protect of individual persons (pedestrians and Like.) To develop a collision (impact) with an automobile suffer.

There the gas generator in a pedestrian protection airbag system outside the vehicle cabin (the interior of the automobile in which the occupants is installed, it is the influences of the external environment and influences, such as e.g. the heat the automotive engine or the like. Suspended, so it required is, countermeasures against these influences to take.

In WO-A-96/27574 describes a gas-forming composition, which is a combination of nitroguanidine and phase-stabilized Ammonium nitrate. This gas-forming composition is thermal stable and has a melting point of not less than 100 ° C. The Ammonium nitrate described in the examples of this document has a phase transition at 120 and 130 ° C and therefore there are volume changes when it is exposed to these high temperatures, so that the gas-forming composition impossible their original one Can maintain shape.

In WO-A-98/04507 is a thermally stable azide-free gas-forming Agent described that a combination of nitroguanidine, tetrazoles and triazoles as propellant (fuel) with phase-stabilized ammonium nitrate or ammonium perchlorate as the oxidizing agent. But when a phase-stabilized ammonium nitrate is added the ammonium nitrate phase changes at 120 and 130 ° C and it occur significant volume changes when it is exposed to these high temperatures, so it impossible is that the gas-forming composition is its original Maintains shape. Furthermore Tetrazoles and triazoles react at 100 ° C with phase-stabilized Ammonium nitrate and decompose, thereby forming ammonia gas becomes. Ammonium perchlorate is for the use in airbag systems not suitable because during the Burning big Amounts of gases such as hydrogen chloride and chlorine are formed.

In WO-A-03/011 798 is a very heat-resistant, strongly cohesive gas-forming agent containing a cationic polymer and an anionic polymer as well as a binder. At the salaries of specific additives However, the operating temperature range for the gas-forming agent to a Value of -40 up to 120 ° C limited and in the examples of this document, only a high-temperature storage test at 107 ° C for 400 h and a heat shock test at -40 up to 100 ° C for 200 Cycles performed.

The heat resistance the gas-forming agents disclosed in the above mentioned documents WO-A-96/27574, WO-A-98/04507 and WO-A-03/011 798 are therefore insufficient, when the gas generator is installed in a place where he easily the thermal effects emanating from an automobile is exposed, for example around the engine compartment.

description the invention

The The present invention relates to a gas generating agent for the gas generator in an airbag system for the protection of a single person who collides with a vehicle, wherein the gas-forming agent is particularly excellent in heat resistance having.

The subject of the present invention is a gas generating agent for a gas generator for an airbag system, which is installed at least outside the vehicle cabin and which is a single person which collides with the vehicle, the gas generating agent having a mass loss rate of not more than 1% after storing in a sealed system at 130 ° C for 400 hours.

The The present invention relates to the above-described gas-forming Agent housed in a gas generator of an airbag system that's at least outside a vehicle cabin is installed.

object The invention is also the use of the above-described gas-forming agent for a Gas generator of an airbag system that is at least outside a vehicle cabin is installed.

The Gas-forming invention Agent includes a propellant (fuel) and an oxidizer and the melting point or decomposition point of the blowing agent (fuel) may preferably not be less than 250 ° C.

The Oxidizing agent of the gas-forming agent of the invention can at least one, selected from the group of basic copper nitrate, sodium nitrate, potassium nitrate, Strontium nitrate, sodium perchlorate, potassium perchlorate and strontium perchlorate, be.

The Gas-forming invention Agent is suitable for the use in a pyrotechnic inflator in which only one Combustion gas as a means for inflating (deploying) the airbag but it can also be used when both a combustion gas as well as a compressed gas (a gas at the argon, helium, nitrogen gas are filled under a high pressure) used as airbag inflating devices or if only a compressed gas is used (in this case, the gas-forming Agent used to break the break plate leading to formation a sealed system is used to control the interior of the Keep inflators under high pressure).

by virtue of its very high heat resistance is the gas-forming invention Agent opposite thermal influences from the outside environment stable and as a result, it can retain the original features of the gas-forming agent for a period of at least 10 years, the life of a Vehicle comply maintained.

The Gas-forming invention Agent can therefore be used for Gas generators are used in airbag systems for protection of individual persons (pedestrians and Like.), which have a collision with a Vehicle suffer, be used.

embodiments the invention

Mass loss rate

One gas-forming according to the invention Agent has a mass loss rate of not more than 1%, preferably not more than 0.8%, and more preferably not more than 0.6%, each after holding at a temperature for 400 hours of 130 ° C in a sealed system. This mass loss rate refers on mass loss, determined using the test method is, as described in the examples below becomes. The individual components of the gas-forming agents, which have the reported mass loss rate, are described below.

components of the gas-forming agent

The Gas-forming invention Agent comprises (a) a propellant (a fuel) and (b) an oxidizing agent and, if necessary, it may contain (c) a binder and / or (d) an additive.

The Propellant component (a) preferably has a melting point or decomposition point of at least 250 ° C. Such a propellant For example, at least one representative selected from among Components of Tables 1 to 5 given below, and the listed below Plastic materials and rubber materials.

In The tables next to the type of blowing agent and its melting point (F.).

Table 1

Table 2

Table 3

Table 4

Table 5

Plastic materials

Phenol-formaldehyde resins, Urea-formaldehyde resins, melamine-formaldehyde resins, unsaturated polyesters, polydiallyl phthalates, Epoxy resins, polyurethanes, polyimides, polyethylenes, polypropylenes, Polystyrenes, acrylonitrile / butadiene / styrene copolymers, polyamides, polymethylmethacrylates, Polyoxymethylenes, polycarbonates, polyethylene terephthalates, silicone resins, Diallyl phthalate resins, dicyclopentadiene resins, polyphenylene ethers, liquid crystal polymers, Polyarylates, polyetherketones, polyamideimides, polyetherimides or the like.

rubber materials

natural Rubber, isoprene rubbers, butadiene rubbers, butyl rubbers, styrene / butadiene rubbers, Nitrile rubbers, urethane rubbers, ethylene / propylene rubbers, Acrylic rubbers, silicone rubbers or the like

The Oxidizing agent component (b) may be, for example, at least a representative selected from the group of basic copper nitrate, sodium nitrate, potassium nitrate, Strontium nitrate, sodium perchlorate, potassium perchlorate and strontium perchlorate. Potassium perchlorate, basic copper nitrate, sodium nitrate and potassium nitrate from the viewpoint of attaining the object of the present invention from the perspective of the above-mentioned representatives.

In the gas-forming invention Agent may, if necessary, a binder as component (c) be used within the range in which the objective of the present Invention is achieved.

When Binders usable are at least one member selected from the group carboxymethylcellulose (CMC), sodium carboxymethylcellulose (CMCNa), potassium carboxymethylcellulose, ammonium carboxymethylcellulose, Cellulose acetate, cellulose acetate butyrate, methylcellulose, ethylcellulose, Hydroxyethylcellulose, ethylhydroxyethylcellulose, hydroxypropylcellulose, Carboxymethylethylcellulose, microcrystalline cellulose, polyacrylamide, aminated polyacrylamide, polyacrylhydrazide, acrylamide / metal acrylate copolymer, polyacrylamide / polyacrylic ester copolymer, Polyvinyl alcohol, acrylic rubber, guar gum, starch, silicone or the like.

In the gas-forming invention Agent can if necessary, various additives as component (d) within a range in which the objective of the present Invention can be achieved.

These Additives can for example, be at least one representative selected from the group of metal oxides, such as copper oxide, iron oxide, zinc oxide, Cobalt oxide, manganese oxide, molybdenum oxide, Nickel oxide, bismuth oxide, gallium oxide, silica, alumina or the like; metal carbonates or basic metal carbonates, such as Cobalt carbonate, calcium carbonate, magnesium carbonate, basic zinc carbonate, basic copper carbonate or the like, metal oxide or metal hydroxide composite compounds such as e.g. Acidic Japanese clay, kaolin, talc, bentonite, diatomaceous earth, Hydrotalcite or the like; the metal acid salts, e.g. Sodium silicate, mica molybdate, Cobalt molybdate, ammonium molybdate or the like; molybdenum disulfide, Calcium stearate, silicon nitride and silicon carbide.

proportions of the components in the gas-forming agent

In the case where the gas generating agent of the present invention contains two components, (a) a propellant (fuel) and (b) an oxidizing agent, the following proportions are preferable in terms of achieving the object of the present invention:
the proportion of the blowing agent (a) is preferably 5 to 65% by mass, more preferably 8 to 60% by mass, and most preferably 10 to 50% by mass; and
the proportion of the oxidizing agent (b) is preferably 35 to 95% by mass, more preferably 40 to 92% by mass, and most preferably 50 to 90% by mass.

In the event that the gas-forming agent of the invention contains three components, (a) a propellant, (b) an oxidant and (c) a binder, the following proportions are preferred in achieving the object of the present invention:
the proportion of the blowing agent (a) is preferably 5 to 60% by mass, more preferably 8 to 55% by mass, and most preferably 10 to 50% by mass;
the proportion of the oxidizing agent (b) is preferably 35 to 95% by mass, more preferably 40 to 92% by mass, and most preferably 50 to 90% by mass; and
the proportion of the binder (c) is preferably 0.1 to 15% by mass, more preferably 1 to 12% by mass, and most preferably 2 to 10% by mass.

In the case where the gas generating agent of the present invention contains four components, (a) a blowing agent, (b) an oxidizing agent, (c) a binder, and (d) an additive, from the viewpoint of achieving the object of the present invention the following proportions are preferred:
the proportion of the blowing agent (a) is preferably 5 to 60% by mass, more preferably 8 to 55% by mass, and most preferably 10 to 50% by mass;
the proportion of the oxidizing agent (b) is preferably 35 to 95% by mass, more preferably 40 to 92% by mass, and most preferably 50 to 90% by mass;
the proportion of the binder (c) is preferably 0.1 to 15% by mass, more preferably 1 to 12% by mass, and most preferably 2 to 10% by mass; and
the proportion of the additive (d) is preferably 0.1 to 10% by mass, more preferably 0.5 to 7% by mass and most preferably 1 to 5% by mass.

The Gas-forming invention Agent can be made by shaping in any desired shape and it can become a shaped body be shaped, for example, the shape of a simple perforated Cylinder, a porous one Cylinder or a pellet. These shaped bodies can be produced by Mixing water or an organic solvent with the gas-forming Agent, to which the extrusion molding (extruding) (in the case of of moldings in the form of a simply perforated cylinder and a porous cylinder) or molding under pressure using a pelletizer or the like. (In the case of a molded article in the form of a pellet).

The Gas-forming invention Agent (or a molded body produced therefrom) is called gas-forming Agent for a gas generator used in an airbag system for protection is used by individuals who are in clash with one Vehicle are exposed, but it can also be used together with general known inflators for Airbags for the driver side, for the passenger side, for Side airbags, for inflatable curtains, for knee pads, inflatable seat belts and tubular systems and as gas generators for auditioning facilities (Straffer) be used.

In addition, can the gas-forming invention Agent or a molded body produced therefrom also as an ignition agent, known as an amplifier (or booster), for the transfer the energy of an ignition device or a detonator capsule on a gas-forming agent.

Mass loss rate

Immediately after introducing 40.0 ± 0.1 g of a well-balanced gas-forming agent (in powder form) into a container (inner volume 118 mL) fitted with a SUS fracture plate (0.2 mm aluminum plate, bursting pressure about 12 kg / cm ² ), the container was sealed. The interior of the container was isolated from the external atmosphere. The container was placed in a thermostat set at 130 ° C and taken out after standing for 400 hours. Then the gas generating agent was again accurately weighed and the mass loss rate was calculated using the following formula: Mass Loss Rate (%) = (initial mass - mass after test) × 100 / initial mass (The terms "initial mass" and "mass after test" refer to the mass of the gas-forming agent).

combustion rate

It a gas-forming composition was prepared and made into a Strand with a diameter of about 9.6 mm and a height of about 12.7 mm shaped. The burning rate was in one nitrogen atmosphere measured at a pressure of 6860 kPa.

example 1

It a gas-forming agent having a composition was prepared the melamine-formaldehyde resin / potassium perchlorate / sodium carboxymethylcellulose (CMCNa) in mass percentage 24.1 / 70.9 / 5 mass percent included. The mass loss rate and the Burning rates were measured using this gas-forming Agent determined. The result was a mass loss rate of 0.3 %, which gives excellent heat resistance points. The burning rate was 14 mm / s, the one represents usable combustion power in practice.

Example 2

A molded article of a gas-forming agent having the composition polyamide-6 / potassium perchlorate in a mass percentage ratio of 16.4 / 83.6 was prepared. The mass loss rate and the burning rate were determined using the shaped body of the gas-forming agent. The result was a mass loss rate of 0.4%, indicating excellent heat resistance. The burning rate was 7.5 mm / s, which is a practical combustion power displays.

Example 3

It became a shaped body from a gas-forming agent with the composition vinylmethyl silicone rubber / potassium perchlorate (Mass percent ratio 21.2 / 78.8). The mass loss rate and the combustion speed were made using the shaped body from the gas-forming Agent determined. The result was a mass loss rate of 0.6 % indicating excellent heat resistance. The burning rate was 18 mm / s, one in the Practice indicates usable combustion performance.

Claims (5)

Gas-forming agent for a gas generator for an airbag system, that at least outside a vehicle cabin is installed and that a single person protects the a collision with a vehicle is exposed, wherein the gas-forming agent after 400 hours Storage in a sealed system at 130 ° C a mass loss rate of not more than 1%. A gas generating agent according to claim 1, which is a propellant (a fuel) and an oxidizing agent, wherein the melting point or decomposition point of the propellant (fuel) at least 250 ° C. A gas generating agent according to claim 2, wherein the oxidizing agent at least one representative selected from the group of basic copper nitrate, sodium nitrate, potassium nitrate, Strontium nitrate, sodium perchlorate, potassium perchlorate and strontium perchlorate, is. A gas-forming agent according to claim 1 or 2, which in a gas generator of an airbag system is arranged, the at least outside a vehicle cabin is installed. Use of the gas-forming agent according to claim 1 or 2 for a gas generator of an airbag system that is at least outside a vehicle cabin is installed.