JP2010536691A5 - - Google Patents

Description

Formation method associated with multi-composition ignition mass

  The present disclosure relates to passive restraint systems, and more particularly, to gas generant ignition materials and methods of manufacturing such materials for use in passive restraint systems.

  The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

  Passive inflatable restraint systems are often used in various applications such as automobiles. One type of passive inflatable restraint system uses an igniting gas generant to activate, for example, an airbag cushion (gas initiator and / or inflator) or to activate a seat belt tensioner (micro gas generator). To minimize occupant injury.

  There is still a desire for improved performance of gas generants. Tuning the performance of the gas generant in an inflatable device system such as an air bag may require a complex design of the hardware system that controls the gas flow as well as the gas generant.

  Often, current gas generants use two or three free ignition materials or different shapes of ignition agents (disc-like or porous) to achieve unique output characteristics for conventional automotive initiators and micro gas generators. It requires dry mixing of grains. Furthermore, the free material can be classified or separated and lead to fluctuations in combustion characteristics.

  Dry mix multiple free ignition materials and / or different shapes of ignition materials to achieve unique and desirable output characteristics (adjusted or fine tunable speed) for conventional automotive initiators and micro gas generators It would be desirable to eliminate or reduce the need. For example, controlled, including adjusting the combustion characteristics of the gas generant to have a sustained output with a slower or faster burn rate or characteristic compared to a typical gas generant mass It would be highly desirable to design an initiator or micro gas generator that has an ignition or modified burn time, thus reducing variability, improving safety and handling, and increasing the performance capability of the ignition material.

  According to various aspects, the present disclosure provides an ignition material for use in a passive restraint system. The material includes a first region having a first igniter composition and a second region having a second igniter composition. The first region forms one or more void regions, the second region is disposed within at least one of the one or more void regions formed by the first region, and the first igniter composition is the second region. A distinction is made from igniter compositions.

  In another aspect, the present disclosure provides an ignition material for use in a passive restraint system. The material includes a first region having a first igniter composition and a second region having a second igniter composition. The first region forms one or more void regions and further has an internal bulk. The second region is disposed in at least one void region in the internal bulk. Furthermore, the first igniter composition is different from the second igniter composition. The first igniter composition and the second igniter composition are fuel, oxidizer, self-ignition agent, binder, slag forming agent, colorant, flow aid, viscosity modifier, dispersion aid, self-igniter, binder. A component independently selected from the group consisting of: slag formers, coolants, flow aids, viscosity modifiers, dispersion aids, desensitizers, excipients, burn rate modifiers, and mixtures and combinations thereof.

  According to another aspect, the present disclosure provides an igniter material for use in a passive restraint system. The material includes a first region having a first igniter composition and a second region having a second igniter composition. The first region is a solid that forms one or more void regions, and the second region is disposed in at least one of the one or more void regions formed by the first region. Furthermore, the surface of the second region is substantially attached to the surface of the first region. Furthermore, the first igniter composition is distinguished from the second igniter composition. Each of the first igniter composition and the second igniter composition includes components independently selected from the group consisting of fuel, oxidant, autoignition agent, binder, and mixtures and combinations thereof.

  According to various aspects, the present disclosure provides a method of forming a multi-composition igniter material that includes filling a slurry into one or more void regions formed by a first solid region. The first solid region includes a first igniter composition, and the slurry includes a second igniter composition that is distinct from the first igniter composition. The slurry disposed within the one or more void regions is dried to form a second solid region, thus forming a multi-composition igniter material.

  In another aspect, the present disclosure provides a method of forming a multi-composition igniter material that includes creating a solid body that includes a first igniter composition. The solid body forms one or more void regions. A second igniter composition is introduced into at least one of the one or more void regions. Also, the first igniter composition is distinguished from the second composition.

  In yet another aspect, the disclosure provides a method of forming a multi-composition igniter material having a first region and a second region that each include a distinct igniter composition. The method includes creating a first region of an igniter material that includes a first igniter composition and creating a second region of an igniter material that includes a second igniter composition. The first igniter composition is distinguished from the second composition. Furthermore, the second region occupies one or more void regions formed by the first region.

  Further areas that can be utilized will become apparent from the description provided herein. The description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

The drawings described herein are for illustrative purposes only and are in no way intended to limit the scope of the present disclosure.
FIG. 1 is a simplified partial side view of an exemplary passive inflatable airbag device system and an exemplary pretensioner system for seat belt restraint in a passenger vehicle. FIG. 2 is an exemplary partial cross-sectional view of an assistant side airbag module including an inflator for an inflatable airbag restraint device. FIG. 3 is an exemplary partial cross-sectional view of a driver side airbag module including an inflator for an inflatable airbag restraint device. FIG. 4 is a cross-sectional view of an exemplary pre-tension system micro gas generator (MGG) used with a pre-tensioner for safety restraint or seat belt systems. FIG. 5 is a plan view of a multi-composition ignition material according to the principles of certain aspects of the present disclosure. FIG. 6 is a cross-sectional view taken along line 6-6 ′ of FIG. 2 shows an exemplary pressure versus time curve for combustion of a multi-composition ignition material. FIG. 8 illustrates another exemplary multi-composition ignition material according to certain principles of the present disclosure. FIG. 9 is an isometric view of a pressed monolith multi-composition gas generant in accordance with certain aspects of the present disclosure. FIG. 10 illustrates an exemplary multi-composition ignition material where the second region can promote the collapse of the ignition material and accelerated combustion in the first region in accordance with certain aspects of the present disclosure.

Description of various aspects

  The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or use. It should be understood that throughout the drawings, corresponding reference numerals indicate similar or corresponding parts and features. The description and specific examples, while indicating various aspects of the disclosure, are intended for purposes of illustration only and are not intended to limit the scope of the disclosure. Furthermore, the description of embodiments having the stated characteristics does not exclude other embodiments having further characteristics or other embodiments containing different combinations of the described characteristics.

  The inflatable restraint device preferably generates gas in situ from the reaction of the ignition gas generator contained therein. In accordance with various aspects of the present disclosure, an ignition material is provided that includes a plurality of compositions in a single lump structure that allows the behavior of the ignition material to have superior performance characteristics in an inflatable restraint device.

  In various aspects, the present disclosure provides an igniter material for use in a passive restraint system. Examples of such ignition materials include igniter and / or initiator materials, micro gas generators, and common gas generants.

  By way of background, inflatable restraint systems include seat belt pretensioner systems and airbag module assemblies for automobile vehicles, such as driver side, passenger side, side impact, curtain and carpet airbag assemblies, such as other types of vehicles, such as It has utility for various types of restraint systems used on ships, airplanes, and trains. Although certain exemplary applications of ignition materials are now discussed, such discussion should not be construed as limiting the utility of the principles of the present disclosure.

  FIG. 1 shows an exemplary driver side forward airbag inflatable restraint device 10. Such driver-side inflatable restraint devices typically include an airbag cushion or airbag 12 that is stored in a steering column 14 of a vehicle 16. A gas generant contained in an inflator (not shown) in the steering column 14 creates a rapidly inflating gas 18 that inflates the airbag 12. The airbag 12 is deployed within milliseconds after detecting the deceleration of the vehicle 16 and creates a barrier between the vehicle occupant 20 and the vehicle component 22 to minimize occupant injury.

  Inflatable restraints typically involve a series of reactions that facilitate gas generation and deploy an airbag or actuate a piston. For example, in an airbag system, the airbag cushion must begin to inflate within a few milliseconds upon operation of the entire airbag assembly system.

  FIG. 2 shows a simplified exemplary airbag module 30 with a compartment 34 covered to accommodate an inflator assembly 32 and an airbag 36 of the passenger compartment. Such devices often use a squib or initiator 40 that is electrically ignited when rapid deceleration and / or a collision is detected. The discharge from the squib 40 normally ignites the initiator or igniter material 42, which burns rapidly exothermically and then ignites the gas generant material 50. The gas generant material 50 burns to create the majority of the gas product that is directed to the airbag 36 and causes inflation.

In various embodiments, the gas generant 50 includes an ignition material and may be in the form of solid masses (grains), pellets, tablets, etc., well known to those skilled in the art. The igniter material contains an igniter fuel, an oxidant, and other minor components that, when ignited, rapidly burn to form gas reaction products (eg, CO ₂ , H ₂ O, and N ₂ ). Gas generants are also known in the art and as ignition materials and / or propellants. Thus, the gas generant material contains one or more compounds that are ignited and undergo a rapid combustion reaction to form heat and gas products, i.e., the gas generant 50 burns to the inflatable restraint device. To produce heated expansion gas.

  Often, slag or clinker is formed near the gas generant 50 during combustion. The slag / clinker serves to sequester various particles and other compounds generated by the gas generant 50 during combustion. In some cases, a filter 52 is provided between the gas generating agent 50 and the airbag 36 to remove particulate matter mixed in the gas and lower the gas temperature before entering the airbag 36.

  FIG. 3 shows a simplified exemplary driver side airbag module 60 having a compartment 62 covered for storing an airbag 64. A squib 66 is disposed centrally within an igniter material 68 that rapidly exothermically burns and then ignites the gas generant material 70. A filter 72 is provided to reduce particulates in the effluent gas entering the inflating airbag 64. Other ignition materials can also be used in the vehicle occupant safety system.

  As shown in FIG. 1, the seat belt 24 may include a pretensioner system 26 that is designed to retract and tighten the seat belt around an occupant in the vehicle. Typically, the seat belt is fastened immediately after the sensor detects the occurrence of a vehicle impact and is known in the art as “pretensioning”. The pretensioner 26 often uses a pretensioning system having a micro gas generator that is ignited, for example, by a sensor mechanism that indicates rapid deceleration of the vehicle. This sensor mechanism is sometimes the same sensor used to detect deceleration for airbag deployment. The micro gas generator is a small ignition material used to generate gas pressure that creates work and typically operates a piston (not shown) in the pretensioner system 26. When the micro gas generator is ignited, the piston is driven to move in the cylinder, pressure is applied to the seat belt 24, and the seat belt around the occupant 20 is retracted and tightened.

  FIG. 4 shows a schematic diagram of an exemplary seat belt protection generator system 80. One or more contact pins 82 pass through the header 84. Pin 82 is sealed through header 84, but carries current generated by an external source (not shown) in response to rapid deceleration of the vehicle to a metal bridge wire or similar ignition member, which is appropriate. When excited by a strong signal, it creates a hot arc or spark and initiates an explosion of the initiator material. Although not shown here, the initiator material is accommodated in a cup-shaped holder or internal can 88 attached to the top of the header 84.

  Holder 88 is fastened to base 90 and is typically sealed thereto by an O-ring or other sealing member 92. The assembly of header 84 and base 90 and associated pin 82 is attached to a metal output can 93 (often referred to as a waveguide can), which is the gas pressure output required to ignite the initiator material 88 contained in holder 88. A gas generant material 94 for producing

  The lower portion of the base 90 typically includes one or more recessed areas 98 that engage a portion of the automotive wire harness, which carries the trigger wire from the sensor circuit to the pin 82. The pretension generator system 80 is disposed in a seat belt pretensioner such as 26 shown generally in FIG.

  As will be appreciated by those skilled in the art, various ignitants including gas generant materials (50, 70, 94) and initiator materials (42, 68, 88) used in airbag module assemblies and / or pretension systems. The material is similar, but preferably its intent, such as rapid combustion for initiation or sustained combustion to generate gas at a preselected pressure for a predetermined time Each performance characteristic is tailored to the specific application. As noted above, the selection of gas generants and initiator materials can be done in accordance with current industrial performance specifications, guidelines and standards, safe gas or effluent generation, continued material stability, and cost in manufacturing. Various factors are involved, including efficiency. The igniter composition is preferably safe during handling, storage and disposal. Furthermore, it is preferable that the igniter composition does not contain an azide.

  In accordance with various aspects of the present disclosure, the igniter material used in the passive restraint system is a second igniter that is distinct from the first region having the first igniter composition and the first igniter composition. A second region having the composition is included. The first region forms one or more void regions. In some embodiments, the first region is a solid or grain formed from the first igniter composition. The second igniter composition is introduced into and disposed within at least one of the one or more void regions to form a second region of an integrated single multi-component igniter material.

  In some embodiments, the solid in the first region has an internal bulk region, and at least one of the void regions extends into the internal bulk of the first region solid, and is optionally disposed substantially therein. . Thus, if second regions are introduced into one or more of such void regions, these second regions are also substantially disposed within the internal bulk of the solid.

  In certain embodiments, the surface of the first region contacts the surface of the second region, and is preferably substantially attached to that surface. Thus, the surface of the first region is integrated with the surface of the second region to provide a physical bond that allows storage and use of the ignitant material without separating the first region from the second region. To bring.

  As mentioned herein, the igniter material has first and second regions, but as will be appreciated by those skilled in the art, multiple regions with different compositions are contemplated. Thus, in some embodiments, the first region forms one or more void regions that can be filled with various igniter material compositions. Thus, as will be appreciated by those skilled in the art, when the first region forms a plurality of void regions, each of these void regions has a plurality of distinct compositions (eg, two The above distinguished igniter composition) can be filled.

  In some embodiments, the first region of the multi-composition igniter (“MCP”) material is pressed or extruded in a general manner to form a porous mass, with a primary shape surrounded by an adjustable inner core or profile. It can be formed by forming concentric or eccentric masses. Typical ignition materials are formed into discs, tablets, wafers, grains, and the like. The first region can be further processed and oven dried before filling with the slurry igniter composition. In another aspect, the first and second regions can be formed simultaneously. The first and second regions of igniter material can be formed in either a batch or continuous process.

  As described above, the first region forms one or more void regions that can be filled with a second igniter composition that solidifies to form a second region that is structurally integrated with the first region. . Non-limiting examples of void areas include cavities, perforations, through-holes, grooves, holes, pockets, channels, etc., which are cylindrical, rectangular, cone-shaped, as described in more detail below. Various shapes including a pyramid shape can be taken in the first region. The void region can also have an irregular shape. In some embodiments, the solid body of the first region can be formed in various shapes having a center or eccentricity, a circle, a square, a star, a cross, or multiple pockets. Accordingly, one or a plurality of void regions are formed by the shape of the first region. Thus, the second region of the igniter material comprising the second igniter composition forms part of the body of the igniter material, unlike a mere coating on the surface of the igniter material, It is structurally integrated.

  It should be noted that the second igniter composition can be introduced into the first igniter material to form void regions during processing and simultaneous fabrication of both materials. Therefore, the void region is not necessarily formed in advance before the introduction of the second composition. For example, the void area is formed by co-extrusion of the first and second igniter compositions or by introducing (e.g., by pouring) the second composition into the first composition prior to solidification of the first composition. Can be done. In any case, the second composition of the various embodiments is integrated with one or more regions of the first region of the igniter material.

  In accordance with the principles of the present disclosure, a unique multi-composition or multi-density or extruded perforated igniter solid mass is formed when the void region is filled with additional igniter material, as described in detail below. The In some embodiments, the igniter material is self-adhesive and achieves desired performance characteristics such as incremental surface area exposure, combustion profile, combustion time, combustion pressure, etc., and more difficult PTC curve (pressure versus time curve) requirements A single multi-composition igniter mass is created that allows easy fine tuning. In some embodiments, any number of suitably shaped central holes (CP) can be created for a desired PTC. Thus, the introduction of several distinct igniter compositions into a single multi-composition mass gives the freedom to adjust or fine-tune the igniter behavior without the need for a variety of separate materials. It is done. In this regard, the multi-component igniter material can provide two or three free ignitions to achieve unique output characteristics (tuned or fine tunable speed) relative to conventional automotive initiators and micro gas generators. Eliminates the need for dry mixing materials or differently shaped ignition materials (eg, discs or multi-perforated masses).

  The principles of the present disclosure allow for the design of igniter materials (eg, initiators, gas generants, or micro gas generators) that have a controlled onset or fast burn time based on the inclusion of the second igniter composition. The first igniter composition has a different composition than the second igniter composition, designs the combustion characteristics of a single igniter material, and further integrates separate materials into a single igniter material structure Both have the advantage of enabling. In this way, any number of different igniter compositions can be selected for the first and second compositions, as will be appreciated by those skilled in the art. The examples provided in this disclosure are merely illustrative and not limiting. In some embodiments, for example, the first igniter composition has a slower burning rate than the second igniter composition. In other embodiments, the second igniter composition has a lower autoignition temperature than the first igniter composition.

  The method of forming such a multi-composition ignition material results in a substantially homogeneous and uniform mixture of materials. Variations often occur when mixing free bulk shapes or providing various material combinations. As previously described, free material is classified or separated, potentially leading to fluctuating combustion characteristics. The disclosed method reduces the variability and has the effect of certain types of agglomerates, such as extrusion or press lumps, that allow for sustained output at slower or more incremental burn rates. This design also fills a single multi-composition mass for various combinations of free ignition materials while still having safety advantages including reducing storage and handling of free dry ignition agents. In order to reduce labor and overhead costs, it is possible to reduce costs by simplifying the process. This method also reduces the need for inspection, individual weight inspection for each combination and ratio completeness, thus achieving improved production / process capability. In various embodiments, the multi-composition igniter mass can be processed continuously to eliminate the complicated drying and slow line speeds of the current overlapping process of the manufacturing process.

  In a broad sense, in various aspects, a method for producing a multi-composition igniter material is provided. The multi-component igniter material is formed by making a first region of the igniter material with the first igniter composition and making a second region of the igniter material with the second igniter composition. The first igniter composition is distinguished from the second igniter composition, and the second region occupies one or more void regions formed by the first region.

  In certain embodiments, the creation of the first region and the creation of the second region can occur simultaneously, eg, the first region and the second region are coextruded with each other and subsequently dried. In other embodiments, the method of creating the first region and the second region is continuous, and first the first region is formed, for example, in solid form, which occurs prior to the creation of the second region. The second region can then be made by introducing the second igniter composition into the void region formed by the first region.

  Accordingly, in one aspect, a method of forming a multi-component igniter material includes filling a slurry into one or more void regions formed by a first solid region. The first solid region includes a first igniter composition, and the slurry includes a second igniter composition that is distinct from the first igniter composition. The slurry disposed within the one or more void regions is dried to form a second solid region, thereby forming a multi-composition igniter material.

  "Slurry" means a fluid or pumpable mixture of fine (relatively small particle size), substantially insoluble particulate solids suspended in a vehicle or carrier. A mixture of solid materials suspended in a carrier is also conceivable. In some embodiments, the slurry comprises particles having an average maximum particle size of less than about 500 μm, in some cases no more than about 200 μm, and in some embodiments no more than about 100 μm.

  Thus, the slurry preferably comprises suspended igniter solids and other materials that are flowable and / or pumpable in the carrier. Suitable carriers include common organic solvents as well as aqueous solvents. In certain embodiments, the carrier may comprise an azeotrope, meaning a mixture of two or more liquids, such as water and certain alcohols, that evaporate at a certain stoichiometric proportion and at a certain temperature and pressure. The carrier is compatible with the components selected to be included in the second igniter composition to avoid adverse reactions and to maximize the solubility of several igniter components of the second composition forming the slurry. It must be selected in consideration of sex. Non-limiting examples of suitable carriers include water, isopropyl alcohol, n-propyl alcohol, or combinations thereof.

  As will be appreciated by those skilled in the art, the viscosity of the slurry of the second igniter composition is controlled by injection, pumping, extrusion, and doctor blade operation as it is introduced into the void region formed by the first region. Or the thing which can be smoothed is preferable. In some embodiments, the viscosity is relatively high and has a thickened or pasty consistency to retain the slurry in the void region. However, the viscosity need not be high, for example, by intentional sealing or sealing of the void area or the nature or shape of the void area within the first area (e.g., the void area completely fills the bulk of the solid first area). In situations where there is no unwanted leakage or discharge and the void area can hold the slurry, the void area may be filled with a lower viscosity liquid slurry, and then dried in the void area. May be. Examples of introducing the slurry into the void area include pumping the slurry, injecting slurry under pressure, extruding the slurry into the desired void area, filling the void area with a doctor blade, and the like.

  In various embodiments, the slurry typically contains about 15 wt% or more; preferably about 20 wt% or more; in some embodiments about 30 wt% or more; in some embodiments about 40 wt% or more. Has water. In some embodiments, the water content of the slurry is from about 15% to about 85% by weight. As the water content increases, the viscosity of the slurry decreases, thus facilitating pumping and handling, while holding the slurry in the void space becomes more difficult.

  Without limitation, in certain embodiments, the slurry introduced into the void region has a suitable viscosity in the range of about 50000 to about 250,000 centipoise. Such a viscosity allows the slurry to flow under the applied pressure, but also has the appropriate rheological properties to maintain the slurry in place stably once applied to one or more void areas prior to drying. It is thought to bring about.

  The slurry (second composition) occupying one or more void regions is then dried, where the slurry forms a second region within the first region, as described above. The drying of the first and / or second zone is usually performed at a temperature ranging from 75 ° C. to over 150 ° C. for a time ranging from 10 minutes to several hours, depending on the desired final moisture content of the solid igniter material. Is done. In another aspect, the first and second regions can be formed simultaneously by co-extruding the first igniter composition with the second composition to form the first and second regions simultaneously.

  In some embodiments, the first region (solid body) having the first igniter composition has a pre-fill density of less than about 70% prior to introducing the second igniter composition into the one or more void regions. Have. The packing density is the actual volume of the igniter material (here the first igniter composition forming the first region) divided by the total volume available for the shape. In other words, there must be a substantial void region formed within the shape of the igniter material that can form the second region. In this regard, the prefill density is less than 100%, preferably significantly less than 100%, indicating that there is sufficient void area in the body shape to form the second area therein. In some embodiments, the prefill density of the first region of igniter material is about 65% or less, in some cases about 50% or less, and in some cases about 40% or less.

  The final packing density of the multi-composition igniter material is the ignitant actually occupied (including the volume of both the first and second regions) after adding the second region to the first region and forming the final igniter material. It is the volume of the material divided by the total volume available for the shape. The final packing density is preferably relatively high in that the void area formed by the first igniter composition is filled with the second igniter composition forming the second area. According to various aspects of the present disclosure, the packing density for the igniter material is preferably about 60% or more, and even more preferably about 70% or more. In some embodiments, the multi-composition igniter material has a packing density greater than about 75%, and in some cases greater than about 80%.

  Thus, in some embodiments, it is not necessary to fill every void region with the second composition, but the second region of the igniter material may optionally be about 5% or more of the total volume of the igniter material shape, preferably about It accounts for more than 10%. In some embodiments, the second region of igniter material comprises about 15% or more of the total volume, and in some cases more than about 25% of the total volume of igniter material.

  The impact (ballistic) characteristics of an igniter material, such as gas generant 50, 70, or 94 shown in FIGS. 2, 3 and 4, typically igniter material composition, shape and surface area, and material combustion. Controlled by speed. Under certain circumstances, it may be desirable to have a void area that does not fill the second area to increase the surface area for combustion of the material in the first area. As noted above, the igniter material can take a variety of shapes and configurations, as will be appreciated by those skilled in the art.

For illustrative purposes, FIGS. 5 and 6 show an exemplary multi-composition igniter material 100. The first region 102 is formed from a first igniter composition, such as a gas generant material containing an igniter fuel and an oxidant. The first region 102 is formed in an annular disc. The inner diameter forms a central void region 112. This void area 112 is first external surface face 104, extending to the second external surface surface 116 opposite the first side 104. The void region 112 was filled with a second igniter composition that subsequently forms the second region 118. In this regard, the multi-composition igniter material has a “bone-medullary” or concentric structure comprising two distinct igniter compositions. Alternatively, the first and second regions 102, 118 can be simultaneously formed into such a structure by co-extrusion of the first and second compositions.

FIG. 7 shows an exemplary pressure versus time curve (PTC). Under the use of a micro gas generator, a high initial pressure is required. Often, this high initial pressure is difficult to achieve with typical gas generants alone, especially because of the small mass and volume available in such systems. As shown in FIG. 7, the desired high initial pressure is the second of the multi-composition igniter material (eg, having a shape similar to that shown in FIGS. 5 and 6), as discussed in detail below. This can be achieved by selecting a second igniter composition, such as THPP or BKNO ₃ , which has a faster burning rate and higher initial pressure for the region than the first composition. . This region of combustion is labeled “A” in FIG. A typical gas generant material for a micro gas generator is provided in the first region and provides sustained combustion and pressure at a relatively slow burning rate, as shown in FIG.

  FIG. 8 shows another alternative structure that includes the igniter material 150. The first region 152 has a first outer surface 154 and a second outer surface 156. A plurality of void regions 158 are formed by the first region 152. The main void region 160 forms a central through hole that extends from the first outer surface 154 to the second outer surface 156. A second igniter composition is disposed there to form a second region 164. The first region 152 does not extend through the inner bulk region 168 of the first region, but begins with either the first surface 154 or the second outer surface 156 and protrudes only partially into the inner bulk region 168. The secondary void region 162 is further included. These secondary void regions 162 may be filled with additional distinct igniter compositions in some cases, but in FIG. 8 are filled with the second composition and are structurally integrated with the first region to form a single unit. It is shown that a further second region 164 ′ is formed which forms the igniter material structure 150.

  In another aspect, for illustrative purposes, FIG. 9 is a US patent application to Mendenhall et al. Entitled “Monolithic Gas Generating Mass” filed June 21, 2006, which is hereby incorporated by reference in its entirety. A single press-formed monolithic gas generant mass shape 210 similar to that disclosed in 11/472260 is shown.

  The combustion pressure resulting from the combustion of the monolithic annular disk mass shape 210 as shown in FIG. 9 is distinguished from that of a typical pellet (cylindrical) or wafer (toroidal ring shape). FIG. 9 shows a first region 210 forming a monolithic mass shape in the form of an annular disc. Exemplary dimensions of the bulk shape of the first region 210 are an inner diameter “a” of about 14 mm, an outer diameter “b” of 41 mm, and a height “c” of about 22 mm. The plurality of through holes 214 extend from the bulky first outer surface 216 of the first region 210 to the second side 218, and thus extend through the body 220 of the first region mass 210 that forms a plurality of void regions 222. Providing an open channel. The inner diameter defined by “a” also forms part of the void region 222. In some cases, some or even all of these void regions 222 are then filled with a second igniter composition that forms the second region 224. As shown in FIG. 9, only some of the void area 222 is filled with the second igniter composition that forms the second area 224.

  As shown, each through hole 214 has a diameter “d” of about 3 mm. The illustrated first region mass 210 has thirty through holes 214, but different structures, dimensions, and amounts of the through holes 214 are also contemplated. The number, size, and location of the through holes 214 can vary as they relate to the desired initial surface area and specific burn rate of the gas generant material. Similarly, the disk dimensions (a, b, and c) can also vary, as will be appreciated by those skilled in the art. For example, if multiple disks are used as the gas generant, the height “c” can be reduced. Thus, the volume that the second region 224 is filled can be selected based on the desired burn time and other performance characteristics, where only a void region 222 is shown in the second region, as shown. 224 is filled.

  The gas generant monolithic mass shown in FIG. 9 preferably has a ratio (L / D) of the length of each through-hole to a diameter of about 3.5 to about 9. In the particular embodiment shown in FIG. 9, the L / D ratio of each through hole is about 7.3. The L / D ratio of the plurality of through holes is related to the increase in the surface area of the gas generant and the overall behavior of combustion. The number of through holes and the L / D ratio of each through hole is related to the shape or profile of the combustion pressure curve of the gas generant material.

  The monolithic shape of the first region gas generant mass 210, similar to that shown in FIG. 9, is long controlled to the desired level, which is important for improved inflator spillage characteristics and occupant safety during airbag cushion deployment. Resulting in a controlled combustion pressure that provides a sustained and maintained combustion pressure.

  In some embodiments, the shape of the void region (ie, the second region) that is filled with the second igniter composition is incrementally created by creating a first region that collapses during combustion to expose additional surface area. Can promote combustion profile. This is conceptually demonstrated in FIG. 10 having an ignitant material 300 that includes a first region 302 formed from a first composition and forming a plurality of conical and / or pyramidal void regions 304. These void regions 304 are filled with the second composition to form second regions 306. The shape of the mass formed by the first region 302 is designed to force structural breakdown of the first region 302 and to allow increased exposed surface area during the combustion process that allows modification of the combustion profile. Can do.

The first region includes fuels, oxidants, autoignition materials , binders, slag formers, coolants, flow aids, viscosity modifiers, dispersion aids, desensitizers, excipients, burning rate modifiers, and mixtures thereof. Having a first igniter composition comprising an igniter component selected from the group consisting of combinations; The general characteristics of each of the classes of igniter components described herein may vary, but there may be some common characteristics, and any given material may serve multiple purposes in two or more of such classes of igniter active ingredients. It is understood that Thus, the classification or discussion of materials in this disclosure as having particular utility is for convenience only and is subject to the classification herein when the material is used in any given composition. Do not make the inference that it must function or must function exclusively. Such igniter components typically improve the functionality and / or stability of the igniter material during storage; modify the burning rate or combustion profile of the gas generant composition; remain after the gas generant material burns Improves slag handling or other material properties; functions to improve the ability to handle or process igniter raw materials.

As noted above, it is preferred that the second igniter composition forming the second region has a composition that is distinct from the first igniter composition so as to desirably provide separate performance characteristics. “Distinguished” means that the first composition differs from the second composition by at least one component and preferably exhibits material differences in ignitant properties. Although the overall composition differs from one another because of such distinct materials, the first igniter composition and the second igniter composition are generally known to those skilled in the art as described herein. Individually and individually selected from the ignition materials. Therefore, the second igniting agent composition forming the second region is also a fuel, an oxidant, an auto-ignition material , a binder, a slag forming agent, a coolant, a flow aid, a viscosity modifier, a dispersion aid, a desensitizing agent, and a shaping agent. An igniter component selected from the group consisting of an agent, a burn rate modifier, and mixtures and combinations thereof. It should be noted that the present disclosure contemplates various igniter compositions known or developed in the art and is not limited to the specific examples described below.

  A typical gas generant material includes at least one fuel. Depending on whether the fuel is fully / autooxidized or underoxidized, the generator may require additional oxidants. Many different ignition materials can be used in the practice of this disclosure. Non-limiting examples of typical igniter fuels suitable for use in either the first or second igniter composition include tetrazole and its salts (eg, aminotetrazole, tetrazole mineral salts), bitetrazole 1,2,4-triazol-5-one, guanidine nitrate, nitroguanidine, aminoguanidine nitrate, metal nitrate and the like. Such fuels are generally classified as gas generant fuels because of their relatively low burning rates. Such fuels typically also require the inclusion of an oxidant.

  In one aspect, a gas generant composition having an appropriate burning rate, density, and gas yield for inclusion in an ignition material of the present disclosure is disclosed in US Patents by Mendenhall et al., The entire disclosure of which is hereby incorporated by reference. Including those described in No. 6958101. US Pat. No. 6,958,101 discloses a suitable fuel for the ignition material of the present disclosure and includes non-azide compounds having substituted basic metal nitrates.

  The substituted basic metal nitrate can include a reaction product formed by reacting an acidic organic compound with a basic metal nitrate. The reaction is thought to occur between acidic hydrogen and basic metal nitrate so that the hydroxyl group of the nitrate compound is partially substituted, but the structural integrity of the basic metal nitrate is compromised by the substitution reaction. There is no. The gas generating agent optionally includes a material containing a substituted basic metal nitrate that is a reaction product of a nitrogen-containing heterocyclic acidic organic compound and a basic metal nitrate.

  Examples of suitable acidic organic compounds include, but are not limited to, tetrazole, imidazole, imidazolidinone, triazole, urazole, uracil, barbituric acid, orotic acid, creatinine, uric acid, hydantoin, pyrazole, derivatives and mixtures thereof. Particularly suitable acidic organic compounds include tetrazole, imidazole, derivatives and mixtures thereof. Examples of such acidic organic compounds include 5-aminotetrazole, bitetrazole dihydrate, and nitroimidazole. According to certain embodiments, preferred acidic organic compounds include 5-aminotetrazole.

  In general, suitable basic metal nitrate compounds include basic metal nitrates, basic transition metal nitrate hydroxy double salts, basic transition metal nitrate layered double hydroxides, and mixtures thereof. Suitable examples of basic metal nitrates include, but are not limited to, basic copper nitrate, basic zinc nitrate, basic cobalt nitrate, basic iron nitrate, basic manganese nitrate and mixtures thereof. In one preferred embodiment, the basic metal nitrate of the replacement compound comprises basic copper nitrate.

  Thus, in one embodiment, the improved burn rate gas generant composition disclosed in US Pat. No. 6,958,101 includes basic metal nitrates such as basic copper, zinc, cobalt, iron and manganese nitrates, basic Transition metal nitrate hydroxy double salts, reaction products of basic transition metal nitrate layered double hydroxides, and mixtures thereof reacted with acidic organic compounds such as tetrazole, tetrazole derivatives, and mixtures thereof.

  Substituted basic metal nitrate reaction products formed include 5-aminotetrazole substituted basic copper nitrate, bitetrazole dihydrate substituted basic copper nitrate, nitroimidazole substituted basic copper nitrate, all disclosed It is a suitable fuel to be used for ignition materials.

  As will be appreciated by those skilled in the art, such fuel compositions can be combined with further components in a gas generant such as, for example, an auxiliary fuel. For example, in one embodiment, the gas generant composition contains a substituted basic metal nitrate as described above and a nitrogen-containing auxiliary fuel. A suitable example of a nitrogen-containing auxiliary fuel is guanidine nitrate. The desirability of using various auxiliary fuels such as guanidine nitrate as part of the fuel in the igniter composition is, for example, burning rate, cost, stability (eg, thermal stability), availability and suitability ( Generally based on a combination of factors such as compatibility with other standard or useful igniter composition components).

  In some embodiments, the gas generant composition comprises from about 5 to about 95% by weight of the substituted basic metal nitrate compound. For example, an improved burn rate gas generant composition may comprise from about 5 to about 95% by weight of 5-aminotetrazole substituted basic copper nitrate. In some embodiments, the igniter gas generant composition comprises about 5 to about 60% by weight of auxiliary fuel. One particular gas generant composition comprises from about 5 to about 60% by weight guanidine nitrate co-fuel and from about 5 to about 95% by weight substituted basic metal nitrate.

  In general, various types of igniter fuels, such as any of those discussed above, are either the first or second igniter composition in an amount of about 5% to about 95% by weight of each igniter composition. Can exist.

Certain igniter fuels have faster burning times, higher reaction rates, and / or lower ignition temperatures and are considered initiators or igniters . In some embodiments, such initiators or igniters are particularly suitable for inclusion in the second igniter composition of the multi-composition igniter material. Such booster materials include ethyl cellulose, nitrocellulose, metal hydride ignition materials such as potassium perchlorate zirconium hydride (ZHPP) and potassium perchlorate titanium hydride (THPP), potassium zirconium perchlorate (ZPP), potassium nitrate. Boron (BKNO ₃ ), cis-bis- (5-nitrotetrazolato) tetraamine cobalt (III) perchlorate (BNCP), and mixtures thereof are included. Some of these igniters , such as ethylcellulose, may require the inclusion of an oxidant. Such booster or initiator fuel may be present in an amount up to about 50% by weight of either the first or second igniter composition.

  Oxidants for igniter compositions are well known in the art and non-limiting examples include alkali, alkaline earth and ammonium nitrates, nitrites and perchlorates, metal oxides, basic Metal nitrates, transition metal complexes of ammonium nitrate and combinations thereof are included. Advantageously, the oxidizer is selected to yield or produce a propellant composition that achieves an effective high burn rate and gas yield from the ignition material upon combustion. Specific examples of suitable oxidizers include potassium perchlorate, ammonium perchlorate or oxidants that do not contain perchloric acid, eg, basic metal nitrates such as basic copper (II) nitrate. Basic copper nitrate (II) has a high metal to oxygen ratio and good slag forming ability. Such oxidizer may be present in an amount up to about 50% by weight of each first or second igniter composition of the igniter material.

The igniter composition optionally contains an autoignition material . Self-igniting agents are a potential explosion, collapse, or rupture of an air bag inflator upon sudden failure in a preselected temperature, preferably a gas generant system, such as extreme heat exposure that exceeds normal operating condition temperatures. It is a material that burns naturally at a lower temperature than can be reached. In current systems, these temperatures can range from about 135 ° C to above about 200 ° C. The autoignition material ignites the booster / initiator composition and / or the gas generant, resulting in safe functionalization of the gas generant at high temperatures. Thus, the gas generant can be ignited by two separate paths including an igniter and an auto- igniter, allowing safe gas generant deployment in abnormal conditions. Such autoignition materials can also be used to increase the combustion of the gas generant during normal operating conditions and actually act as a booster composition. Furthermore, autoignition materials can improve the coupling of certain ignition materials to each other.

The autoignition material may contain a single autoignition agent or mixture of agents that is formulated to autoignite at the desired preselected temperature. Some examples of suitable autoignition materials known in the art include silver nitrate and smokeless gunpowder, such as those sold by DuPont under the trade name IMR4895. Other examples of suitable auto-ignition material is in its entirety by reference is incorporated herein, the auto-ignition material comprising a mixture of azodicarbonamide (ADCA) fuel and basic copper nitrate (II) (BCN) oxidizing agent Including those disclosed in US Patent Application Publication No. 2006/0102259 to Mendenhall et al.

  Binders are commonly used in igniter compositions to preserve the shape of the gas generant solids, particularly when they are formed by extrusion and / or molding, and to prevent crushing during storage and use. The Further, in this application, the binder second composition can function to adhere to the first composition, thereby forming a structural bond between the first region and the second region. For example, a dry mix of various igniter components can be mixed with a liquid binder resin, extruded, and cured. Alternatively, the solid polymer binder mass can be dissolved in a solvent or heated to the melting point and then mixed with other igniter components and extruded or molded. As described above, in certain embodiments, the first igniter composition may optionally not include a binder, but in certain embodiments, both the first and second may be added to increase adhesion and bonding therebetween. It may be desirable to provide a binder in the igniter composition. In various embodiments, a binder in the second igniter composition is desirable.

  Suitable binders, such as polymeric binders, include organic film formers, inorganic polymers, thermoplastic and / or thermosetting polymers. Examples of common polymeric binders include, but are not limited to, natural rubber, cellulosic esters, polyacrylates, polystyrene, silicones, polyesters, polyethers, polybutadienes, and mixtures and combinations thereof.

  Other suitable ignition additives include slag formers, flow aids, viscosity modifiers, press aids, dispersion aids, or desensitizers. Non-limiting examples of slag formers such as refractory compounds are aluminum oxide and / or silicon dioxide. In general, such slag formers may be included in each igniter composition in an amount of 0 to about 10% by weight.

  A coolant to lower the gas temperature, such as basic copper carbonate or other suitable carbonate, may be added to the igniter composition at 0 to about 20% by weight. Similarly, press aids used during compression processing include lubricants and / or mold release agents such as graphite, magnesium stearate, calcium stearate and may be present in the igniter composition from 0 to about 2%. . In some embodiments, the ignition material may optionally include low levels of certain binders or excipients to improve crush strength without significantly harming spill and combustion characteristics. Such excipients include, by way of example, microcrystalline cellulose, starch, carboxyalkylcellulose, such as carboxymethylcellulose (CMC). When present, such excipients may be included in each igniter composition at less than 10% by weight, preferably less than about 5% by weight, more preferably less than about 3%.

  Also, certain components can be added to change the combustion profile of the igniter fuel material by changing the pressure sensitivity of the slope of the combustion rate. One such example is copper bis-4-nitroimidazole. Agents having such an effect are referred to herein as pressure sensitive modifiers and they can be present in any igniter composition from 0 to 10% by weight of the agent. Such additives are described in more detail in US Patent Application No. 11/385376 to Mendenhall et al. Entitled “Gas Formation with Copper Complexed Imidazole and Derivatives,” the entire disclosure of which is incorporated herein by reference. Yes. Other additives that are conventionally known or developed for ignition materials are also for use in various embodiments of the present disclosure, as long as they do not unduly impair the desired combustion profile characteristics of the ignition material. Can think.

  Other advantages of the present disclosure include hardware simplification in an airbag module or pretensioner assembly. As can be appreciated, combining several different types of materials into a single igniter composition potentially eliminates the need for separate initiators and / or multiple (ie, two-stage) driver inflators. . The two drive inflators have two distinct gas generants that are staged into the inflator device to achieve the desired combustion and combustion profile. In a two-stage inflator, the first gas generant provides sufficient gas product to inflate the airbag cushion during the first combustion period, but during the required time over the entire period of impact / impact. Insufficient combustion rate and gas yield to maintain cushion pressure. Thus, a second gas generant (often having a different composition) is ignited in the second stage, providing a pressurized gas product to the bag for a second period of impact. Such staging can also be used to respond in proportion to the impact force during a collision, depending on the severity of the collision. However, two-stage drivers have complex mechanical hardware and control systems and are costly. Furthermore, dual gas generants can cause uncontrolled sympathetic ignition reactions.

  For example, a typical configuration for a dual stage driver includes nesting a second igniter system within the first igniter system. Dual igniters create duplication for various hardware components including storage devices, electrical wiring, initiators, shorting clips, staged cups, lids, more complex bases, and so on. In addition, other gas generant filling stations are required for further stages of the generant. During operation, control of the combustion pressure during the second stage of ignition is difficult because the first stage may still be ignited and / or the surrounding area is already heated with pressurized gas. The flow area between the lid and cup may not be constant and it may be difficult to control the combustion pressure from the second stage. Further, complexity can potentially arise due to combustion gas leakage from the first stage to the second stage where unintended combustion of the second stage generator can occur. Thus, by providing two gas generant compositions in a single gas generant mass, the need for such complex hardware is potentially eliminated.

Similarly, the need for large igniter systems can be reduced or eliminated by including a booster material in the gas generant. Similarly, the inclusion of autoignition material in a single mass of ignitant material can simplify the structure of the system device by eliminating the need for separate storage of the autoignition material . Thus, the flexibility afforded by the principles of the present disclosure allows for the further potential avoidance of safety and performance complications through the use of improved ignition materials in a single unified structure according to various embodiments of the present disclosure. Providing the possibility to reduce and / or eliminate complex hardware and staging systems. In addition, such materials allow for favorable designs including improved burn rates, combustion timing, combustion profiles, and spillability to tune the performance of various igniter materials.

  Embodiments of the present disclosure can be further understood by the specific examples contained herein. Specific examples are provided to illustrate how to make the compositions of the present disclosure and how to use the methods of the present disclosure, and unless otherwise stated, It is not intended that the described embodiments be implemented or not practiced, or produced or tested.

Example 1
In one example, a 5-aminotetrazole substituted basic copper (II) nitrate fuel for a gas generant is formed by the exemplary substitution reaction (1) described above. 72.7 lb of 5-aminotetrazole is placed in 42 gallons of warm water to form a 5-aminotetrazole solution. Slowly add 272.9 lbs of basic copper (II) nitrate to the 5-aminotetrazole solution. 5-aminotetrazole and basic copper (II) nitrate are reacted at 90 ° C. until the reaction is substantially complete. To the reaction mixture is added 139.95 lb guanidine nitrate and 14.45 lb silicon dioxide. The slurry mixture is then spray dried.

A release agent (inert carbon, ie, graphite) and 20.83 lb of basic copper carbonate (coolant) are dry mixed with the spray dried composition. The mixed powder is placed in a pre-molded mold having a desired shape, such as an annular disk shape having a plurality of through holes or void areas as shown in FIG. The mold and powder are placed in a large high tonnage hydraulic press capable of exerting pressures exceeding 50 tons. The raw material is pressed to form a monolithic gas generant solid.
The slurry is prepared by mixing 24.4 g water, 75 g BKNO ₃ and 0.6 g hydroxypropyl methylcellulose binder for 8 minutes. The slurry has a viscosity of approximately 25000 to 35000 cP. The slurry is applied on top of a monolithic solid and the pores are filled with the slurry. The doctor blade compresses the material and removes excess material. The monolithic mass having through holes filled with the slurry is dried at 165 ° C. for 1 hour to form a solid multi-composition igniter solid mass.

  The present disclosure still further provides an igniter composition that is economical to manufacture. The present disclosure also provides an igniter material with improved combustion rate that overcomes one or more of the limitations of conventional gas generants.

  While specific embodiments have been described in the specification and shown in the drawings, various modifications can be made to the members and equivalents can be made without departing from the scope of the present teachings as set forth in the claims. It will be understood by those skilled in the art. Further, the combination or matching of features, components and / or functions between the various embodiments is expressly contemplated herein, and one skilled in the art, unless otherwise stated, is one embodiment. It will be understood from the present teachings that the features, members and / or functions may be incorporated into other embodiments as appropriate. In addition, modifications may be made to adapt a particular situation or material to the present teachings without departing from the essential scope thereof. Accordingly, the present teachings are not limited to the specific embodiments shown in the drawings and described in the specification as the best presently contemplated mode for carrying out the teachings, and the scope of the present disclosure is It may be intended to include any embodiments within the scope of the claims.

Claims (11)

A first region having a first ignition composition comprises a second region having a second ignition composition, the first igniting agent composition Ru is distinguished from the second ignition composition, passive restraint In the ignition mass used in the system ,
-The first region has a first outer surface and a second outer surface opposite the first outer surface ;
The first region has a plurality of void regions formed by a plurality of through holes extending from the first outer surface to the second outer surface , and a portion of the plurality of void regions is Filled with the second igniter composition to form the second region,
An ignition mass characterized by that . The ignition mass according to claim 1, wherein the first igniter composition includes a gas generant fuel, and the second igniter composition includes an igniter . The ignition lump according to claim 1, wherein the first igniter composition includes a gas generant fuel, and the second igniter composition includes an auto-ignition material . A method of forming an ignition mass according to any one of claims 1 to 3 ,
Creating a first region of the ignition mass with a first igniter composition;
To produce a second region of the ignition mass in the second ignition composition; wherein the first igniting agent composition Ru is distinguished from the second composition, methods. The production of the first region includes forming a solid of the first igniter composition before the production of the second region, and the production of the second region comprises the plurality of the first solid region The method according to claim 4 , further comprising introducing the slurry into the part of the void regions , and then drying the slurry. The method of claim 5 , wherein the slurry has a water content of 15 wt% or more. The method according to claim 5 or 6 the slurry has a viscosity of from 5 0000 2 50000 centipoise. The method of claim 5, wherein the slurry comprises at least two compounds that form an azeotrope . The method of claim 5, wherein the slurry comprises particles having an average maximum particle size of less than 500 μm . The method according to claim 4, wherein the production of the first region and the production of the second region are performed simultaneously . The method of claim 10, wherein the first region and the second region are coextruded with each other and subsequently dried .