JP5426062B2 - Foam ignition materials used in automotive airbag inflator devices - Google Patents

Description

  The present invention relates generally to ignition compositions for use in inflator devices for inflatable restraint systems. More particularly, the present invention relates to a foamable ignition composition that forms a foam ignition material when heated to a predetermined temperature.

  It is well known to protect an occupant with a gas inflated cushion or bag, such as an “airbag cushion” when the vehicle suddenly decelerates, such as in a collision. Such airbag restraint systems are typically attached to one or more airbag cushions that are stored in an uninflated and collapsed state to minimize the footprint and to the vehicle frame or body. One or more crash sensors that detect when the car is suddenly decelerated, a starter system that is electronically started by the crash sensor, and an inflator device that generates or supplies gas to inflate the airbag cushion And. When the car suddenly decelerates, the crash sensor starts the starting system, which in turn starts the inflator device and begins to inflate the airbag cushion within a few milliseconds.

  Many types of inflator devices are known in the prior art for use in inflating one or more airbag cushions of an inflatable restraint system. Conventional inflator devices include a solid form of a gas generating material that, when burned, generates or forms gas that is used to inflate the associated airbag cushion.

  In such an inflator device, it is common to cause a series of reactions to the material (for example, pyrotechnics) contained therein to generate or generate an expansion medium, for example, an expansion gas, and to expand the airbag cushion. Is. For example, such devices typically use an ignition device or detonator that ignites electronically when a collision is detected. The discharge from the igniter generally ignites igniter material located near the igniter. It is desirable for the ignition material to burn relatively quickly to produce a large amount of heat and to ignite the gas generant material uniformly. The gas generating material then burns to generate or form gas and is sent to the associated airbag cushion to inflate the airbag cushion. In general, the impact properties of a gas generant material are determined by the shape of the gas generant material (usually a tablet or wafer) and the burning rate.

  As will be appreciated, the ability of the gas generant to ignite quickly and repeatedly can ignite the air bag cushion associated with the passive restraint system of the person riding the vehicle in a very short time. It is extremely important to provide an inflator device that can be spread reliably. For example, inflator designers are generally required to ensure that gas is released from the inflator within 3 milliseconds of operating the system.

  Inflator designs have been found to be mostly unsuccessful when attempting to incorporate spark powder simply by blending or mixing gas generating tablets, wafers or other forms of gas generating particles. In particular, in the inflator having such a design, the ignition powder tends to escape from the ignition device and the gas generating particles as time passes. As a result, an inflator with such a design may cause unacceptable delays and occupant protection may not be optimal.

  In view of the above, conventional inflator devices have some form of ignition material so that the ignition material is properly positioned within the inflator device so that the ignition and reaction of the accompanying gas generant material occurs as desired. It is common to package with. More particularly, inflator devices typically contain powdered igniter material packaged in separate containers near the igniter and gas generant particles. With such a configuration, the ignition device can quickly ignite the ignition powder, and as a result, the gas generating material ignites quickly.

  In practice, if the packaging of such igniting material is relatively easy and simple, for example, the igniting material is placed in a small canister, such as an aluminum canister, at the center of a donut driver inflator device When packaging is relatively complicated, for example, the ignition material is placed in a tubular device, and the tubular device is placed inside a gas generating wafer stack included in a passenger inflator device that is generally cylindrical. Insert into. Regardless of the design, it is generally necessary to incorporate extra parts to accommodate the powder igniter material in the inflator device, which not only increases weight but also increases assembly and manufacturing costs.

  As another approach, the ignition composition can be applied to the surface of the gas generant material, or the surface of the gas generant material can be coated with the ignition composition. For example, to deposit the ignition composition on the outer surface of the gas generant material in the form of a wafer or tablet, spray the ignition composition onto the wafer or tablet, or place the wafer or tablet into a bath containing the ignition composition. It is good to soak. Coating the gas generant material, regardless of the application method, generally increases manufacturing costs and requires quality control to ensure that the wafer or tablet is uniformly and well coated with the ignition composition.

  Another approach is to compress the igniter material into particles of the same size as the gas generant material, and intentionally place the igniter particles in a mass of gas generant material near the igniter. Is. Specific examples of this method include an ignition material wafer located at the end of the gas generation wafer stack adjacent to the ignition device, or an ignition material wafer periodically disposed along the length direction of the gas generation wafer stack, Among the side impact inflators, the ignition material tablet located at the end of the ignition device consisting of the gas generation tablet floor, the ignition material tablet placed in the gas generation wafer laminate, and the donut-shaped driver inflator device The ignition material tablet located at the center of the gas generating tablet floor, and the same idea other than these are mentioned. Unfortunately, compressed ignited particles generally have a much smaller surface area compared to the same mass of ignited powder. As will be appreciated, as the surface area of the igniter material decreases, the rate of energy release during combustion generally decreases, which can cause undesirable ignition delays in the airbag inflator device. In addition, the ignited particles compressed in this way can become brittle, and thus are subject to breakage or decomposition over time when exposed to shock and / or vibration and / or thermal changes. Such breakage or decomposition can cause the ignition material to exit the igniter and / or gas generating material, resulting in an undesirable delay in ignition time.

  In view of the above, there is a need and demand for an ignition material that is resistant to breakage, has the same size as the gas generant particles, and has the same surface area as the powder ignition material.

  One general object of the present invention is to provide an improved igniter material and a method for producing such an igniter material in connection therewith.

  One more specific object of the present invention is to solve one or more of the above problems.

  The general above objective of the present invention is, at least in part, a foamable igniter composition effective to form a foamed igniter material comprising a fluoropolymer bound oxidant and a flexible fluoropolymer bound oxidant. A plasticizer effective to form a metal fuel that reacts with a fluoropolymer-bound oxidant, a foaming agent effective to make the foamable ignition composition porous, and a structurally stable foam ignition material Realized by a foamable ignition composition, characterized in that the foamable ignition composition forms the foamed ignition material when heated to a predetermined temperature. Is done.

  In the prior art, a foamed ignition material that is generally the same size as the gas generating particles but has a surface area similar to that of the powder ignition material in use has not been realized. The prior art generally does not provide a foamable ignition material that can be extruded or molded and that can form a foamed ignition material having a predetermined shape when heated to a predetermined temperature. Further, the prior art has not realized a foamable ignition composition that is generally applicable to surfaces and forms a foamed ignition coating with improved elasticity and impact resistance when heated to a predetermined temperature.

  The present invention provides a method for producing a foamed ignition material, comprising a fluoropolymer-bound oxidant, a plasticizer effective to soften the fluoropolymer-bound oxidant, and a metal fuel that reacts with the fluoropolymer-bound oxidant. A foamable ignition composition comprising: a foaming agent effective to make the foamable ignition composition porous; and a crosslinking agent effective to structurally stabilize the foamed ignition material. Also included is a method comprising heating to a temperature effective to at least partially decompose the igniter to foam the ignition composition and crosslinking the resulting foamed igniter composition to form a foamed igniter material.

The present invention further includes a foamable ignition composition effective to form a foamed ignition material comprising:
From about 10 to about 60% by weight of the composition of a fluoropolymer bound oxidant;
About 1 to about 40% by weight of a plasticizer effective to soften the fluoropolymer bound oxidant;
About 10 to about 50% by weight of a metal fuel that reacts with the fluoropolymer-bound oxidant;
From about 0.1 to about 30% by weight blowing agent effective to make the foamable ignition composition porous;
About 0.5 to about 5 weight percent of a crosslinker effective to structurally stabilize the foam ignition material and when heated to a predetermined temperature, the foamable ignition composition forms the foam ignition Also included are foamable ignition compositions characterized in that they form a material.

  The present invention, according to one preferred embodiment thereof, further includes a damper pad cushion for use in an automotive airbag inflator device formed of a foamable ignition composition. The present invention, according to another preferred embodiment thereof, further includes a hybrid gas storage container including a foamed ignition material adhered to the inner surface of the container. The present invention, according to yet another preferred embodiment thereof, includes a foamed ignition material of a predetermined shape, such as a cylindrical or stick shape, formed from an extruded foamable ignition composition.

  Objects and advantages other than those described above will become apparent to those skilled in the art from the following detailed description, taken in conjunction with the accompanying claims and drawings.

  The present invention provides a foamable ignition composition for use in an inflator device of an inflatable restraint system. More particularly, the present invention provides a foamable ignition composition that forms a foam ignition material when heated to a predetermined temperature.

  In accordance with the present invention, a foamable ignition composition includes a fluoropolymer-bound oxidant, a plasticizer effective to soften the fluoropolymer-bound oxidant, a metal fuel that reacts with the fluoropolymer-bound oxidant, Includes a blowing agent effective to make the foamable igniter composition porous and a crosslinking agent effective to structurally stabilize the foamed igniter material. Generally, a foamable ignition composition foams and crosslinks to form a foamed ignition material when heated to a predetermined temperature. The foamable ignition composition preferably foams and crosslinks when heated to a predetermined temperature to form an elastic foam ignition material. The foam ignition material retains the desired shape and surface area due to its resistance to breakage or decomposition, and effectively ignites the accompanying gas generant material.

  In general, it is desirable for the fluoropolymer-bound oxidant to react sufficiently with the metal fuel to sufficiently burn the foamed igniter material formed from the foamable ignition composition of the present invention. In addition, it is desirable that the fluoropolymer bound oxidant be crosslinked to structurally sufficiently stabilize the foamed igniter material formed from the foamable igniter composition of the present invention. It is desirable that the fluoropolymer-bonded oxidant provides adhesive properties to the foamable ignition composition and effectively adheres the foamed ignition material formed from the foamable ignition composition of the present invention to a given surface.

  Various fluoropolymer binders have been found that are suitable for use as oxidants in the foamable ignition compositions of the present invention. One such fluoropolymer binder material is, for example, a fluoropolymer elastomer material available from DuPont Dow Elastomers L.L.C. under the registered trademark VITON. More specifically, suitable fluoropolymer bound oxidizers for use in foamable ignition compositions include dipolymers of vinylidene fluoride and hexafluoropropene, vinylidene fluoride, hexafluoropropene and tetrafluoroethene. Examples include terpolymers, and combinations thereof. In certain preferred embodiments, the foamable igniter composition comprises a dipolymer of hexafluoropropene and vinylidene fluoride.

  In general, foamable igniter compositions contain a sufficient amount of a fluoropolymer-bound oxidant to completely burn the composition. The foamable igniter composition preferably comprises from about 10 to about 60% by weight of a fluoropolymer bound oxidant.

  In the present invention, a variety of plasticizers that are effective to soften the fluoropolymer bound oxidant can be used. Suitable plasticizers include fluorocarbon oils. A particularly suitable plasticizer is polytrifluorochloroethylene.

  Generally, the foamable igniter composition includes a sufficient amount of plasticizer to soften the fluoropolymer bound oxidant. In general, foamable ignition compositions contain from about 1 to about 40% by weight of the plasticizer of the composition.

  The foamable igniter composition also includes a metal fuel that reacts with the fluoropolymer bound oxidant. In general, it has been found that certain metals react with fluoropolymer materials to form metal fluorides, releasing a relatively large amount of heat. Metals that react with the fluoropolymer include, but are not limited to, aluminum, barium, beryllium, boron, calcium, lithium, sodium, strontium, titanium, zirconium, and mixtures or alloys of these metals. Suitable metal fuels that will react with the fluoropolymer in the practice of this invention include aluminum, magnesium, alloys of aluminum and magnesium, and combinations thereof. In certain preferred embodiments, the metallic fuel that reacts with the fluoropolymer is metallic magnesium.

  In general, the foamable ignition composition of the present invention includes an amount of metal fuel that reacts with the fluoropolymer sufficient to effectively ignite the combined gas generant material. More specifically, the foamable igniter composition of the present invention comprises from about 10 to about 50 weight percent of a metal fuel that reacts with a fluoropolymer bound oxidant.

  The foamable igniter composition of the present invention preferably also includes a blowing agent effective to render the composition porous. It is preferable that the foaming agent can be provided in the form of particles, solid, or liquid. Suitable blowing agents for practicing the present invention generally include blowing agents that decompose into gas species when heated. In practice, a blowing agent that is at least partially decomposed by heat and becomes a gas at a temperature lower than the autoignition temperature of the combined ignition composition is preferred. In general, since such decomposition temperatures are below 350 ° C, the foamed ignition material need only be heated to a temperature below 350 ° C. A blowing agent that decomposes at least in part at 100 ° C. to 300 ° C. is believed to be most useful and desirable for practicing the present invention to make the foamable ignition composition porous.

  Furthermore, although it is generally preferred to use a blowing agent that decomposes all into gas species, the resulting solid decomposition product does not substantially inhibit the combustion of the foamable ignition composition or is a foamable ignition composition. The broader scope of the present invention need not be narrowly limited unless it is detrimental to combustion. Examples of useful blowing agents that generally produce gaseous products include aminoguanidine bicarbonate, ammonium oxalate, azodicarbonamide, ammonium carbonate, ammonium carbamate, ammonium bicarbonate, 4,4'-oxydibenzene hydrazide , P-toluenesulfonyl semicarbazide, organic acids and the like. Other useful blowing agents that generally decompose to only gaseous products include, but are not limited to, solvents such as acetone, ethyl acetate, butyl acetate, amyl acetate, and the like. Other useful blowing agents that generally decompose and leave some solids include alkali metal and alkaline earth metal carbonates or bicarbonates such as basic copper carbonate, metal amine carbonates such as copper carbonate diamine, Examples include metal amine salts of organic acids such as copper diamine oxalate and metal salts of organic acids. In certain preferred embodiments, the blowing agent included in the foamable igniter composition is p-toluenesulfonyl semicarbazide.

  In general, it is desirable in the practice of the present invention that the foamable igniter composition includes from about 0.1 to about 30% by weight of the composition of the blowing agent.

  The foamable igniter composition further includes a crosslinker. The cross-linking agent is effective in structurally stabilizing the foamed ignition material, and it is desirable that the porous structure formed when the foaming agent is decomposed is retained in the foamed ignition material. More specifically, the cross-linking agent reacts with the fluoropolymer bond oxidant to form a chemical bond or cross-link to cure the foamable igniter composition foamed by heating to a porous foam igniter. It is desirable. Such bonds or crosslinks are resistant to breakage or destruction due to sudden shocks or vibrations that occur during storage in the combined inflator device, while the foam igniter material burns. It is desirable that the surface area of the foamed ignition material be further increased by being relatively easily broken.

  In general, crosslinkers that can structurally stabilize the foam igniter without adversely affecting the desired performance of the foam igniter are suitable for use in the present invention. However, in certain preferred embodiments, the crosslinker comprises at least one bifunctional crosslinker and at least one peroxide crosslinker. For example, the cross-linking agent can include the bifunctional cross-linking agent trimethylol propane trimethacrylate alone or in combination with a peroxide cross-linking agent such as benzoyl peroxide.

  In practice, the foamable igniter composition can include from about 0.5 to about 5 weight percent of a suitable crosslinker. More specifically, the foamable igniter composition can include about 0.5 to about 5.0% by weight of a bifunctional crosslinker and about 0.5 to about 5.0% by weight of a peroxide crosslinker.

  The foamable igniter composition may further comprise up to about 65% by weight of an auxiliary oxidant. Suitable auxiliary oxidants according to certain preferred embodiments of the invention include alkali metal and alkaline earth metal nitrites, nitrates, chlorates and perchlorates, ammonium nitrate, ammonium perchlorate; transition metal One or more of oxides, hydroxides, carbonates, nitrates and perchlorates, transition metal complex nitrates, nitrites and perchlorates, and the like.

  The present invention also includes a method for preparing a foamed ignition material comprising the foamable ignition composition described above. In particular, according to certain preferred embodiments, the foamed ignition material causes the ignition composition to foam by heating at least a portion of the blowing agent by heating the foamable ignition composition of the present invention to a predetermined temperature. And then foaming the foamed composition to form a foam ignition material. In general, foamable igniter compositions become porous by at least partially decomposing the blowing agent upon heating to a predetermined temperature between about 160 ° C and about 200 ° C.

  Depending on the desired end use, before heating, the foamable igniter composition can be applied to the surface to be coated with the foamed igniter material, extruded to the desired shape, or the desired shape The mold can be filled and pressure can be applied during heating.

  In practice, the foamable ignition composition of the present invention comprises a precursor solution comprising a fluoropolymer-bonded oxidizer, a plasticizer, and at least one crosslinker, such as a bifunctional crosslinker. It can be prepared by mixing with a precursor blend comprising a metal fuel that reacts with the agent and a blowing agent. The precursor solution can be prepared by solvating a fluoropolymer bound oxidant, a plasticizer, and a crosslinker with a solvent, such as acetone. Thereafter, the precursor blend can be added to the precursor solution and stirred to disperse the precursor blend in the precursor solution to form a foamable ignition composition.

  Depending on the desired end use of the foamable ignition composition, some or substantially all of the solvent can be removed from the foamable ignition composition. For this purpose, the desired consistency is achieved, for example, by sprinkling the mixture with a stream of air prior to heating.

  For example, according to one preferred embodiment, the foamable ignition composition of the present invention can be made into a particulate material by, for example, spraying the composition with an air stream until substantially all of the solvent is removed. it can. This particulate material can be molded into the desired shape. For this purpose, for example, the granular material is filled in a mold and pressure is applied during heating. This foamable ignition composition is used, for example, to form foam damper pads, cushions used in inflator devices, and the combined gas generant material deteriorates when subjected to vibrational energy or physical shock. It is good to prevent it from being damaged.

  According to another embodiment, the foamable ignition composition of the present invention has a consistency putty-like material or paste material by sprinkling the composition with a stream of air until the desired amount of solvent is removed. It can be made to be comparable. The resulting foamable igniter composition can be extruded into a predetermined shape, such as a cylinder or a stick.

  According to yet another embodiment, the foamable ignition composition of the present invention can be applied to the surface by methods such as spraying, dipping, rolling, brushing and the like. The foamable ignition composition can then be heated to a predetermined temperature to form a coating of foamed ignition material.

  As will be appreciated by those skilled in the art, the foamable ignition composition of the present invention can be utilized in a variety of ways in a variety of inflator devices. For example, the foamable ignition composition described above can be used in a single stage inflator device to prevent the gas generant material from being damaged or decomposed by vibration or impact.

  Referring to FIG. 1, a single stage inflator device 110 has a generally cylindrical outer contour and includes a housing 112. The housing 112 is formed of, for example, two structural members: a lower shell or base 114 and an upper shell or diffusion cap 116. Desirably, these members can be joined or sealed together in any suitable manner.

  The housing 112 is generally structured to define a cylindrical chamber, which is represented here by reference numeral 118. The chamber 118 contains a gas generating material 120 in a desired selected shape, such as a pyrotechnic known in the prior art. A filter group 122 surrounds the gas generating material 120.

  The inflator device 110 includes a holder 124, a diffusion damper pad cushion 126, and a base damper pad cushion 128, and these members do not require the gas generating material 120 inside the inflator device 110. Prevents noise and contact. In practice, as already explained, the diffusion damper pad cushion 126 and / or the base damper pad cushion 128 may be formed by molding a foamable ignition composition and heating it to a predetermined temperature under pressure. It can be composed of a foamed ignition material.

  The inflator device 110 further includes an ignition assembly, generally designated by reference numeral 130. The ignition assembly 130 includes, for example, an ignition device 132 and an adapter or holder 134 for the ignition device. The igniter 132 is attached or fitted to the housing 112 through the attachment opening 136 and comes to a position in the chamber 118.

  Activation of the igniter 132 ignites the foamed igniter material of the diffusion damper pad cushion 126 and / or the base damper pad cushion 128. The product obtained by this ignition comes into direct contact with the gas generating material 120 accommodated in the chamber 118 through a predetermined configuration. For example, the gas generating material 120 is ignited to start a reaction. The gas produced by this reaction exits the inflator device 110 and enters a combined airbag cushion (not shown).

  It will be appreciated that the inflator device 110 does not require parts such as an ignition cup or an ignition tube. Such unnecessary parts can actually reduce the weight and / or size of the inflator device and improve the reliability of the performance, so that the inflator device can be manufactured and / or attached, And / or the costs associated with the operation can be significantly changed, i.e. reduced.

  In certain preferred embodiments, the foamable ignition composition described above can be used to form a foamed ignition material that adheres to the inner surface of the inflator device. For example, referring to FIG. 2, a hybrid inflator device, generally designated 210, includes a foamable igniter composition that is applied to at least one inner surface thereof.

  The hybrid inflator device 210 includes a pressure vessel 212 having a storage chamber 214. The storage chamber 214 is generally filled with an inert gas, such as argon, helium, nitrogen, or a reactive gas, such as nitrous oxide, that is pressurized to about 2000 psi to about 4000 psi. The hybrid inflator device 210 also includes a diffuser 216 and an ignition assembly 218. Desirably, these members can be joined or sealed together in any suitable manner. The diffuser 216 includes a rupture disk (burst disk) 240. The rupturable plate 240 has a role of sealing and separating the gas contained in the storage chamber 214 from the diffuser 216.

  The hybrid inflator device 210 further includes a filling port 220 used for gas pressurization. The filling port 220 is integrated with the pressure vessel 212 and is appropriately sealed by ball welding 222 or the like after being pressurized.

  The hybrid inflator device 210 further includes a foam igniter coating 224 that contacts at least a portion of the inner surface of the pressure vessel 212. In practice, as previously described, the foamable ignition composition of the present invention is applied to at least a portion of the selected inner surface of the pressure vessel 212 and then heated to a predetermined temperature to provide the foamed ignition material coating 224. It is desirable to form.

  The ignition assembly 218 includes an ignition device 226 and an ignition device adapter or holder 228. The igniter adapter 228 is suitably attached or fitted to the ignition assembly 218 through the mounting opening 230. The ignition assembly 218 also includes a pyrotechnic filling 232 contained in a container 234 adjacent to the orifice 236. Orifice 236 is sealed by a rupture plate 238 attached to the ignition assembly 218.

  In operation, the igniter 226 ignites the pyrotechnic filling 232 contained in the container 234. The pyrotechnic filling 232 pierces the vessel 234 and the rupture disc 238 to produce a reaction product containing a sufficient amount of hot flame and gas. The released gas and hot flame pass through orifice 236 and ignite foam igniter coating 224. The product obtained by this ignition comes into direct contact with the gas contained in the chamber 214 through a predetermined configuration. When the gas is heated, the pressure in the storage chamber 214 rises to a sufficient level and breaks through the rupturable plate 240. As such, the heated gas is released into the diffuser 216 and passes through the hybrid inflator device 210 into the associated airbag cushion (not shown).

  As will be appreciated by those skilled in the art from the description herein, the hybrid inflator device 210 does not require parts of the gas heater assembly, such as a gas generation cup or associated hardware. Such unnecessary parts can actually reduce the weight and / or size of the inflator device and improve the reliability of the performance, so that the inflator device can be manufactured and / or attached, And / or the costs associated with the operation can be significantly changed, i.e. reduced.

  In another preferred embodiment, the foamable igniter composition described above can be utilized to form a foamed igniter material having a predetermined shape, such as a cylindrical or stick shape. For example, the airbag inflator device 310 shown in FIG. 3 includes a housing 312 that is elongated and generally cylindrical. The housing 312 is made of a metal such as steel or aluminum and has a cylindrical side wall 314. Around the side wall 314, a plurality of gas ports or gas holes 316 are provided at appropriate intervals for releasing a gas for inflating an associated airbag (not shown) when the inflator device 310 is operated. Yes.

  The housing 312 becomes a circular end wall 318 integrated with the housing and is closed at one end. At the center of the end wall 318 is an outwardly projecting mounting pin 320 that is used to secure the inflator device 310 to a selected, suitable location, such as the back of an automotive instrument panel or dashboard. The opposite end of the housing 312 is closed by an annular end wall 322. The annular end wall 322 has an opening in the center, and an igniter 324 is inserted therein for initiating the gas generation process and inflating the associated airbag cushion. The annular end wall 322 is formed by any one of metal bending, rolling, and inertia welding in a state where all the components housed in the inflator device 310 are placed in a predetermined position and held in the predetermined position. The housing 312 is sealed by a formed annular deformed end flange 326.

  Inside the housing 312, a plurality of washer-like annular gas generating wafers 328 are accommodated as elongated cylindrical laminates 329 and extend between both end walls 318 and 322. The expansion gas is rapidly generated when the plurality of washer-like annular gas generating wafers 328 are ignited and burned. The wafer 328 is formed of a solid material made of sodium azide or other type of gas generating material and generates a large amount of relatively inert gas when the wafer is ignited. Each wafer 328 includes a central opening 330 or a core passage. The central opening 330 forms one short section of an elongated central passage 332 that extends through the entire wafer stack 329 extending between both end walls 318 and 322 within the housing 312. Wafers 328 at both ends of stack 329 are separated from adjacent housing end walls 318 or 322 by annular spacers 334 or 336, respectively. A central core or central passage 334a is formed in the spacer 334, and a central core or central passage 336a is formed in the spacer 336, forming a partition at both ends of an elongated central passage 332 formed by a plurality of wafers 328. .

  A cylindrical laminate 329 composed of a plurality of solid gas generation wafers 328 is surrounded by an elongated hollow tubular filter 338. The filter 338 cools the hot gas generated when the gas generating wafer 328 reacts and filters out the hot particles so that the hot particles are otherwise expanded out of the gas discharge port 316 and expanded. Prevents damage to the bag and its immediate environment. The filter 338 can be a number of layers 340 made of metal screen material or other types of filter media. The gas port 316 is sealed by adhering a thin metal foil 342 to the inner surface of the side wall 314 of the housing so as to prevent contaminants from entering the inside of the housing 312. When the gas generating wafer 328 is ignited, the metal foil 342 is easily broken by the gas pressure in the housing 312, so that the generated gas flows freely from the gas discharge port 316 and the accompanying airbag cushion is inflated.

  In accordance with the present invention, the foam igniter material 346 is disposed within the elongated central passage 332. The foamed igniter material 346 has a predetermined shape (for example, a cylindrical shape or a stick shape), and may be disposed in an elongated central passage 332 adjacent to the igniter 324. For example, in some preferred embodiments, the foam igniter material 346 can be disposed in the elongate central passage 332 in contact with and adjacent to the igniter 324. In another preferred embodiment, as shown in FIG. 3, the foamed igniter material 346 is disposed within the elongate central core passage 332 adjacent to the igniter 324 but at a reasonable distance from the igniter 324. can do.

  When the igniter 324 is activated, the foam ignition material 346 is ignited to ignite the gas generating wafer and to start generating expansion gas. The inflation gas generated by this ignition passes through the inflator device and into the associated airbag cushion (not shown).

  As can be appreciated, the inflator device 310 does not require components such as ignition tubes, rapid deflagration or RDC cables. Such unnecessary parts can actually reduce the weight and / or size of the inflator device and improve the reliability of the performance, so that the inflator device can be manufactured and / or attached, And / or the costs associated with the operation can be significantly changed, i.e. reduced.

  The invention will now be described in more detail with reference to the following examples. The following examples illustrate various features related to the practice of the present invention. Any changes within the spirit of the invention are to be protected and therefore the invention is not to be limited to this example.

  Foamable ignition compositions according to the present invention as shown in Table 1 below were prepared. A fluoropolymer binding oxidizer (a dipolymer of vinylidene fluoride and hexafluoropropene, available under the VITON A trademark from DuPont Dow Elastomers LLC) and a plasticizer containing polytrifluorochloroethylene Solvated with the same weight of acetone to form a solution. Next, a bifunctional crosslinker containing trimethylolpropane trimethacrylate was added to the solution to form a precursor polymer solution. A dry blend containing magnesium as the metal fuel, p-toluenesulfonyl semicabazide as the blowing agent, and benzoyl peroxide as the cross-linking agent was mixed to form a precursor blend. This precursor blend was thoroughly mixed into the precursor polymer solution to form a foamable ignition composition.

  The foamable ignition composition prepared as described above had the properties or characteristics shown in Table 2 below.

  The main combustion products produced by ignition of the foamable ignition composition described above include carbon, magnesium fluoride, and hydrogen. Since such combustion products are rich in fuel components, the foamed ignition material of the present invention is used in a hybrid inflator device as a gas generating material having a low fuel component or an additional oxidant such as oxygen, nitrous oxide. It is desirable to increase energy output in combination with.

  Accordingly, the present invention provides a foamable ignition composition that can form a foam ignition material by heating to a predetermined temperature. The resulting foamed ignition material can be used in an inflatable restraint device inflator device. More specifically, according to the present invention, heating to a predetermined temperature forms a porous foam igniter material that is similar in size to a combined gas generating material and has a surface area similar to that of a powder igniter material. A foamable ignition composition is provided. Furthermore, the present invention provides a foamable ignition composition capable of forming a foamed ignition material having a predetermined shape, such as a damper pad cushion shape, by extrusion or molding. The present invention also provides a foamable ignition composition that can be formed on a surface to form a foam ignition material coating.

  In the present specification, the present invention is described for the purpose of explanation. Therefore, the present invention can be appropriately implemented even without elements, portions, steps, parts, and components not specifically disclosed in the present specification.

  Moreover, while the foregoing detailed description has described the invention in connection with certain preferred embodiments and has presented many details for purposes of illustration, those skilled in the art will recognize that the invention It will be apparent that there are other embodiments, and that some of the details described in this specification may be changed significantly without departing from the basic principles of the invention.

1 is a side cross-sectional view of a single stage inflator device including a damper pad cushion formed from a foamable ignition composition. FIG. 1 is a side cross-sectional view of a one-stage hybrid inflator device having an inner surface coated with a foamed igniter according to an embodiment of the present invention. 1 is a side cross-sectional view of a single-stage occupant inflator device including a cylindrical ignition stick formed from a foamable ignition composition, according to one embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 110 Single stage inflator apparatus 112 Housing 114 Base part 116 Diffusion cap part 118 Chamber 120 Gas generating material 130 Ignition assembly

Claims (23)

A foamable ignition composition effective to form a foam ignition material,
An oxidant comprising a fluoropolymer elastomer material as a binding material;
A plasticizer effective to soften the oxidizing agent;
A metal fuel that reacts with the oxidant;
A thermally decomposable blowing agent effective to render the foamable ignition composition porous by decomposition;
And a cross-linking agent effective to structurally stabilize the foam ignition material, and the foamable ignition composition forms the foam ignition material when heated to a predetermined temperature. A foamable ignition composition.   The foamable igniter composition of claim 1, wherein the foamable igniter composition forms an elastic foamed igniter material when heated to a predetermined temperature.   2. The foamable ignition of claim 1, wherein the oxidant is selected from the group consisting of vinylidene fluoride and hexafluoropropene dipolymers, vinylidene fluoride, hexafluoropropene and tetrafluoroethene terpolymers, and combinations thereof. Composition.   The foamable ignition composition of claim 1, wherein the plasticizer comprises a fluorocarbon oil.   The foamable ignition composition of claim 1, wherein the metal fuel is selected from the group consisting of aluminum, magnesium, an alloy of aluminum and magnesium, and combinations thereof.   The blowing agent is selected from the group consisting of aminoguanidine bicarbonate, ammonium oxalate, p-toluenesulfonyl semicarbazide, 4,4′-oxydibenzene hydrazide, acetone, ethyl acetate, butyl acetate, amyl acetate and combinations thereof; The foamable ignition composition according to claim 1.   The foamable ignition composition of claim 1, wherein when heated to a predetermined temperature, the cross-linking agent chemically reacts with the oxidizing agent to structurally stabilize the foamed ignition material.   The foamable ignition composition according to claim 1, wherein the crosslinking agent comprises at least one bifunctional crosslinking agent and at least one peroxide crosslinking agent. A hybrid gas storage container used in a car safety restraint system,
The foamable ignition composition of claim 1 attached to the inner surface of the hybrid gas storage container,
When heated to a predetermined temperature, the foamable ignition composition forms a foamed ignition material and adheres to the inner surface of the hybrid gas storage container. A foam ignition material having a predetermined shape,
Comprising the foamable ignition composition of claim 1;
The foamable ignition composition has an effective consistency to allow the ignition composition to be extruded, and when heated to a predetermined temperature, the foamable ignition composition has a predetermined shape. A foam ignition material characterized by forming a foam ignition material having A method for producing a foam ignition material, comprising:
Heating the foamable ignition composition of claim 1 to a temperature effective to at least partially decompose the blowing agent to foam the ignition composition;
A manufacturing method comprising cross-linking the obtained foam ignition composition to form a foam ignition material. The method of claim 11 , wherein the foamable igniter composition is heated to a temperature between 160 ° C. and 200 ° C. during heating. 12. The method of claim 11 , wherein the foamable igniter composition is applied to a surface to be coated with the foamed igniter material prior to heating. 12. The method of claim 11 , further comprising extruding the foamable ignition composition into a predetermined shape prior to heating. The method of claim 11 , further comprising filling the foamable ignition composition into a mold and applying pressure during heating. A foamable ignition composition effective to form a foam ignition material,
10 to 60% by weight of the composition of an oxidant comprising a fluoropolymer elastomer material as a binding material;
1 to 40% by weight plasticizer effective to soften the oxidant;
10-50% by weight of a metal fuel that reacts with the oxidant,
0.1-30% by weight of a thermally decomposable blowing agent effective to render the foamable ignition composition porous by decomposition;
And 0.5-5% by weight of a cross-linking agent effective to structurally stabilize the foamed ignition material, and the foamable ignition composition comprises the foamed ignition material when heated to a predetermined temperature. A foamable ignition composition characterized in that it is formed. 17. The foamable igniter composition of claim 16 , wherein the oxidant is a dipolymer of vinylidene fluoride and hexafluoropropene. 17. The foamable igniter composition of claim 16 , wherein the plasticizer is polytrifluorochloroethylene. 17. The foamable ignition composition according to claim 16 , wherein the metallic fuel is metallic magnesium. 17. The foamable igniter composition of claim 16 , wherein the blowing agent comprises p-toluenesulfonyl semicarbazide. 17. The foamable ignition composition according to claim 16 , wherein the crosslinking agent comprises at least one bifunctional crosslinking agent and at least one peroxide crosslinking agent. The foamable ignition composition of claim 21 , wherein the bifunctional crosslinker is trimethylolpropane trimethacrylate. 24. The foamable igniter composition of claim 21 , wherein the peroxide crosslinking agent is benzoyl peroxide.

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