KR20060021321A - Flexible inflator with co-extruded propellant and moisture barrier and gas generating propellant compositions for use therewith - Google Patents

Abstract

A flexible inflator for an inflation assembly and related gas generating propellant compositions are provided. The flexible inflator includes at least one elongated strand of a propellant co-extruded with a moisture barrier. The propellant compositions are adapted for co-extrusion with a plastic sheath which forms the moisture barrier surrounding the propellant and include a binder fuel component effective to render the composition flexible and to impart sufficient adhesive properties such that the propellant composition and the plastic sheath adhere together, and an oxidizer.

Description

FLEXIBLE INFLATOR WITH CO-EXTRUDED PROPELLANT AND MOISTURE BARRIER AND GAS GENERATING PROPELLANT COMPOSITIONS FOR USE THEREWITH}

The present invention relates generally to a general apparatus for producing a gas, such as used for the expansion of an inflatable element, such as in the form of a cushion or curtain included in an inflatable restraint system of a vehicle. More particularly, the present invention relates to a flexible inflator that can be easily applied for placement at various locations inside a vehicle.

It is known to protect a vehicle occupant using a cushion or bag, for example an "airbag cushion", which expands or unfolds with gas when the vehicle experiences a sudden deceleration such as a crash situation. Such airbag restraint systems typically have one or more airbag cushions, housed in unexpanded and folded conditions to minimize the need for space, one or more crash sensors mounted to or on the frame or body of the vehicle to detect sudden deceleration of the vehicle. And an inflator device having an activation system electronically released by the collision sensor and a gas generating compound or propellant whose combustion produces or provides gas to inflate the airbag cushion. In the event of a sudden deceleration of the vehicle, the collision sensor announces an activation system which in turn announces an inflator device that begins to inflate the airbag cushion in milliseconds.

Develop and tailor various types or forms of such inflatable restraint systems to provide the desired vehicle occupant protection, for example, based on one or both of the nature or direction of the vehicle crash and the position or placement of the occupant in the vehicle. come. In particular, in the case of the frontal type of vehicle crash, occupant and passenger inflatable restraint arrangements have found wide utility to provide protection for occupant and front passenger respectively. However, occupant and passenger inflatable restraints generally do not provide as much protection as desired against the impact of the vehicle being applied or imposed from a direction other than the front, i.e., "side impact." In that regard, considerable effort has been made to develop inflatable restraints with special effects in the case of side impacts.

The inflatable curtain restraint device is a relatively new development in the field of inflatable restraint systems. In general, such inflatable curtain restraints are located inside the vehicle frame along the ceiling adjacent to the door frame of the vehicle. Typically such inflatable curtain restraints have an inflatable curtain designed to deploy at least a portion of the door frame and / or above the window of the vehicle to protect the occupant from the impact of the door frame and / or window, in particular a side impact or rollover. Include. Such inflatable curtain restraint devices also typically include an inflatable device for providing an inflatable fluid, typically in the form of a gas, to inflate the inflatable curtain. Articles such as inflatable curtain restraint devices are disclosed in US Pat. No. 5,788,270 to Hland, et al., The disclosure of which is incorporated herein by reference.

Many types or forms of inflator devices have been disclosed in the art for use in inflatable restraint systems. One particularly common type of inflator device is usually referred to as a pyrotechnic inflator. In such an inflator device, the gas used in the expansion of the relevant inflatable element is obtained from the combustion of the flame gas generating material or propellant. However, if the gas generating material or propellant is exposed to shocks and impacts related to moisture or non-collision, the combustion efficiency and thus the effect of the inflatable restraint system can be offset. Therefore, in practice, the gas generating material is typically protected from moisture and shock by placing the material in a separate vessel or housing.

Flame inflator devices, as used for inflating inflatable curtains, are primarily cylindrical in shape and typically have a length greater than the diameter of the inflator device. Indeed, the length / diameter ratio of such inflator devices has been constrained and limited by the general need or desire to ensure relative uniformity of flammability over the length of the inflator device. In particular, even small diameter assemblies have proven difficult to obtain ignition of extended lengths of flame gas generator or propellant material in a uniform manner. In addition, inflatable restraints, such as inflatable curtains commonly designed to provide protection beyond extended zones, are typically required to allow for rapid expansion over relatively extended lengths, as compared to normal frontal impact inflatable restraints. . The provision of an inflation gas, produced by combustion of a flame gas generator or propellant material, preferably along an extended length in a uniform and fast manner, can be particularly challenging to achieve.

Many of today's vehicles have rounded or contoured chassis to promote aerodynamic performance and improved fuel efficiency. As a result, the position in the vehicle where the inflatable curtain restraint device is typically disposed is correspondingly contoured or curved. The inflatable curtain restraint device, therefore, comprising an inflator device and preferably individual components, is advantageously flexible so that the inflator device fits a wide variety of contours of the vehicle.

In addition to the above challenges, manufacturing, assembly, and cost reduction benefits are continuing major objectives to be considered to be achieved in the design and development of assemblies and components and components and modern vehicles contained therein.

Therefore, there is a need and desire for a flexible inflator device that is easier to manufacture and assemble and that can be easily adapted to various locations within various vehicles of a vehicle. There is also a need and desire for an inflator device that displays sufficient stability beyond the system life inside the vehicle. There is further a need and desire for an inflator device that is balanced for use with an inflatable curtain that provides effective combustion of the propellant component and a uniform inflator of the inflatable curtain. There is still further a need and desire for an inflator device that can be employed in a variety of vehicle sizes and types and / or a variety of vehicle interior orientations and locations and is flexible.

It is a general object of the present invention to provide an improved inflator device for the expansion of inflatable elements, such as airbag cushions or inflatable curtains included in inflatable restraint systems for vehicle occupants.

A more specific object of the present invention is to overcome one or more of the problems described above.

A general object of the present invention can be reached, at least to some extent, through a flexible inflator comprising at least one component of a co-extruded propellant and a moisture barrier.

The prior art generally fails to provide a flexible inflator for use in an inflatable restraint system of a vehicle that can be easily adapted for deployment at various locations inside various vehicles. In addition, typical inflators of the prior art include two components, a gas generator or propellant compound and a container or housing, which are manufactured separately and later assembled, thus leading to additional manufacturing and assembly steps and expenses. In addition, many of the propellant composites commonly used in inflatable restraint systems allow the inflator device used in the inflatable curtain safety restraint system to be contoured at various locations inside various vehicles without offsetting the ignition and gas evolution properties of the propellant. Lack of adequate flexibility

The invention further includes a gas generating propellant composite applied for co-extrusion with a plastic sheath useful for forming a strand comprising a propellant and a moisture barrier that can be used in a flexible expander. The propellant composite attaches the propellant composite and plastic sheath together, including a binder fuel component and an oxidant that are effective for the propellant composite to be flexible and impart sufficient adhesion.

The present invention still further comprises an extrudable gas generating propellant composite comprising a composite weight ratio binder fuel component of about 5 to about 20 effective to make the composite flexible and a composite weight ratio oxidant of about 5 to about 80.

The present invention additionally includes a gas generating propellant compound adapted for coextrusion with a plastic sheath, wherein the propellant compound is about 5 to about 20 effective to make the composite flexible and to impart sufficient adhesive properties to adhere the propellant compound and the plastic sheath together. A composite weight ratio binder fuel component of about 5 to about 80, a composite weight ratio oxidizing agent, and a composite weight ratio plasticizer of about 5 to about 30, wherein the binder fuel component comprises polyvinyl chloride, polyester, polyurethane Propellant composites comprising a polymer selected from the group.

Reference herein to a material or composite with “gas evolution” produces or forms at least about 2.5 moles of gas per 100 grams of composite and preferably produces at least about 3.0 moles of gas per 100 grams of composite It will be understood to refer to a material or composite, such as when forming or forming and burning with a standard oxidant such as sodium nitrate.

As used herein, reference to “burn front” or “flame front” begins at the inner axial surface of the central bore formed in the propellant core and proceeds from the first lateral end to the longitudinally opposite second lateral end. It will be understood to refer to the essentially linear ignition of the propellant core of the coextruded strand. This propagation in front of the combustion must meet a minimum propagation rate to ensure the expansion of the associated airbag cushion or curtain with proper ignition and inflation gas of the propellant core.

Other objects and advantages will become apparent to those skilled in the art from the following detailed description considered in conjunction with the appended claims and drawings.

1 is a perspective view of a flexible inflator according to any embodiment disclosed herein.

FIG. 2 is a longitudinal sectional view of the flexible expander of FIG. 1. FIG.

3 is a perspective view of the flexible expander of FIG. 1 after ignition.

4 is a perspective view of a flexible inflator showing yet another embodiment of the present invention.

5 is a perspective view of a flexible inflator according to any additional embodiment.

6 is a cutaway schematic diagram illustrating a structure underneath an inflatable restraint system disposed inside a vehicle that includes a flexible inflator of the present invention.

As described in more detail below, the present invention provides a flexible inflator, such as for the expansion of an inflatable element, such as an inflatable curtain or airbag cushion provided in a vehicle inflatable restraint system. More particularly, the present invention is directed to providing or supplying an inflation gas through the combustion of a gas generating propellant compound in one or both of a more suitable manner or effectively distributed more uniformly or over an extended length. Any application that provides a flexible inflator comprising at least one strand of co-extruded propellant and a moisture barrier and wherein at least any expandable curtain restraint system may be desirable to utilize or employ such a flexible inflator. May be preferred. The present invention further provides a propellant composite applied for co-extrusion with a plastic sheath that may be used or used to form like a flexible expander device.

As will be appreciated, the invention can be practiced in a variety of other structural varieties. Referring to Figure 1, there is shown a flexible inflator, which is the generally illustrated invention. The flexible inflator 10 includes a fragile joint generally designated by reference numeral 36 and is generally applied for use in connection with an inflatable restraint system, as described in more detail below. In FIG. 1, the flexible inflator 10 is shown in a static or rest state. The flexible inflator 10 includes at least one propellant-containing strand 12 having a generally elongated tubular shape in which the propellant forms an extruded core 14 with an outer axial surface 16. The flexible inflator 10 further includes a coextruded plastic sheath 18 externally adjacent the outer axial surface 16 of the propellant core 14 to form a barrier that protects the propellant core from moisture. Propellant core 14 includes a central bore 20 extending coaxially of central longitudinal axis 22 through propellant core 14 to form an inner axial surface 24. The central bore 20 may have a generally circular cross section, as shown in FIG. 1, or may have another suitable cross section, as taught by the teachings provided herein and as apparent to those skilled in the art.

Suitably, the propellant core 14 comprises a gas generating propellant composite adapted to be extrudable and coextruded with the plastic sheath 18. Such propellant composites typically include a binder fuel component and an oxidant. In general, the propellant composite of the present invention may advantageously include a composite weight ratio binder fuel component of about 5 to about 20 and a composite weight ratio oxidant of about 5 to about 80.

Useful Propellant Synthetic oxidants include alkali, alkaline earth and ammonium nitrate, nitrate and perchlorate, metal oxides and basic metal oxides. Transition metal complexes of ammonium nitrate, and combinations thereof. The oxidant content of the propellant composite can be varied to optimize combustion rate, impact, friction and electrostatic (ESD) conductivity and thermal stability of the propellant composite and thus propellant core 14. Advantageously, the oxidant is selected to provide and result in a propellant compound that achieves high combustion rates and gas emissions efficiently upon combustion. Specific examples of suitable oxidants include potassium perchlorate and ammonium perchlorate.

Advantageously, the binder fuel component is efficient to make the propellant composite and thus the propellant core 14 flexible and impart sufficient adhesion so that the propellant composite is attached to the coextruded plastic sheath 18. Suitable examples of binder fuel components include silicones, polybutadiene, polyvinyl chloride, polyamide, polyurethane, polyacryl, polyacrylamide ( polyacrylamide) and combinations thereof.

In one aspect, the binder fuel composite imparts adhesion of the propellant core 14 to the coextruded plastic sheath 18 through physical or chemical bonding at the surface boundaries of the core and sheath, and binds the product composite into the solid homogeneous material. Binder fuel composites that impart cohesion and undergo a curing reaction to crosslink the polymer include polymers such as crosslinkable silicone, polybutadine, polyurethane, or combinations thereof. Crosslinkable polymers can have a range of molecular weights, and the crosslinking of the polymers can be performed at various grades to achieve the desired mechanical properties. One particularly suitable crosslinkable binder fuel component includes silicone.

In another aspect, the binder fuel component may comprise a polymer that is extrudable by dissolution extrusion or through solvation with a solvent. Suitably, the polymer imparts adhesion of the propellant core 14 to the extruded plastic sheath 18 simultaneously through physical or chemical bonding at the surface boundaries of the core and sheath and bonds the product components together with a solid homogeneous mass. It is solvated at elevated temperatures with a plasticizer to form a liquid phase which gives upon cooling and floats and evenly mixes the components of the propellant product.

In practice, the propellant composite includes a composite weight ratio binder fuel component of about 5 to about 20 and a composite weight ratio plasticizer of about 5 to about 30 for solvating the binder fuel component. In particular, suitable binder fuel components include silicones, polybutadienes, polyesters, polyvinyl chlorides, polyamides, polyurethanes, polyacrylates, polyacrylamides and combinations thereof. Examples of suitable plasticizers include esters of dioctyl adipate or phthalic acid, esters of dicarboxylic acids such as sebacic or malonic acid. Silicone oils are also used to plasticize silicone polymers.

If desired, the propellant component of the present invention may employ auxiliary fuels in the range of up to about 20 compound weight ratios. Advantageously, the auxiliary fuel is a cool combustion, nitric acid containing organic fuel. Examples of such materials include, but are not limited to, guanidine, strands, ureas, tetratrazoles, related derivatives thereof, and combinations thereof.

The propellant composite of the present invention may also advantageously comprise a coolant. In practice, the propellant composite according to the invention preferably utilizes such coolant in an amount effective to achieve low flame temperatures, such as between about 1226 ° C. (1500K) and about 2726 ° C. (3000K), without adversely inhibiting combustion of the propellant compound. It may include. In general, the propellant composite may include up to about 30 composite weight ratio coolants. Examples of such coolants include alkali, alkaline earth and transition metal carbonates and oxilates, basic metal carbonates and combinations thereof.

If desired, the propellant composite of the present invention may further comprise an auxiliary oxidant in an amount effective to optimize the composite properties with desired parameters related to the end use of the composite properties composite, such as burn rate, impact and ESD charge and thermal stability. Suitably, the propellant composite of the present invention may comprise such auxiliary oxides in an amount up to a composite weight ratio of about 60. Examples of suitable auxiliary oxidants include, but are not limited to, alkalis, alkaline earth metal perchlorate, nitrates and nitrites.

Advantageously, the propellant composite according to the invention may comprise at least one or both of a relatively small proportion of coolant or auxiliary oxidant. As will be appreciated, the combustion of such propellant composites, especially oxidants, can produce unwanted byproducts such as, for example, hydrochloric acid fumes. Using both or both coolant and auxiliary oxidant in the propellant composite provides a technique for cleaning hydrochloric acid from a gas stream through the formation of filterable metal halides during combustion of the propellant core 14. For example, a propellant composite comprising a binder fuel material and an oxidant such as ammonium perchlorate may be used as an aid such as sodium nitrate in an amount sufficient to be cleaned or reacted with virtually all hydrochloric acid formed or released during combustion of the oxidant. It may preferably comprise an oxidizing agent. Suitably, the propellant composite according to the invention comprises up to about 5 parts per million hydrochloric acid or up to 7.5 mg / m ³ and also comprises a certain amount of one or both of a coolant or auxiliary oxidant effective to cause an effluent or swelling gas. can do.

Additional additives such as burn rate catalysts or processing aids may also be included in the propellant composite to catalyze the burn rate and improve the composite process capability. In general, such additives may be included in the propellant compound at relatively low concentrations, such as up to about 10 compound weight ratios.

The invention is described in more detail in connection with the following examples of illustrating or simulating the various aspects included in the practice of the invention. In addition, all changes that fall within the spirit of the invention are intended to be protected, and therefore the invention is not to be construed as limited by these examples.

One example of a propellant composite suitable for use in the present invention is a composite weight ratio silicone binder fuel component of about 5 to about 20, a composite weight ratio ammonium perchlorate oxidant of about 5 to about 75, and a composite weight ratio of about 60 Up to an amount of auxiliary oxidant and up to about 30 compound weight ratios of coolant.

Another example of a propellant composite of the present invention is a polyvinyl chloride binder fuel component of about 5 to about 20, a plasticizer in the composition weight ratio of about 5 to about 30, and potassium perchlorate in the composition weight ratio of about 50 to about 80 An oxidant and a coolant of a size up to a composite weight ratio of about 30.

Further examples of propellant composites applied for co-extrusion with plastic sheaths include polyesters in a composite weight ratio of about 5 to about 20, plasticizers in a composite weight ratio of about 5 to about 30, and to promote effective combustion of the propellant composite. An oxidant of a size effective to and a coolant of a size up to a composite weight ratio of about 30.

Plastic sheath 18 may include any material capable of forming a flexible moisture barrier for propellant core 14 and capable of acting as a pressure containment mechanism to enhance ignition of propellant core 14. Advantageously, the plastic sheath 18 is resistant to rupture or breakdown, is resistant and extends when the propellant core 14 is ignited. In other words, the plastic sheath 18 may act as a mechanism for directing the generated inflation gas without breaking into pieces or particulates when the propellant core 14 is ignited. In addition, the plastic sheath 18 may comprise any material that completely bonds to the propellant composite and together facilitates coextrusion. Advantageously, the plastic sheath 18 may have the same chemical structure as the binder fuel component of the propellant composite.

Strand 12 is center bore 20 to facilitate propagation of the flame or combustion front from first lateral end 28 to second lateral end 30 disposed opposite the length of strand 12. May advantageously include the amount of ignition enhancer 26 disposed along at least one portion of the inner shaft surface 24 formed by. In general, effective infestation of the flame or combustion front is such that the propellant core 14 ignites substantially along the entire length of the core and uniformly inflates the cushion or curtain associated with the airbag cushion and, in particular, the inflation gas associated with the inflatable curtain. It is desirable to ensure delivery along the total length of the flexible inflator 10. Advantageously, the ignition enhancer 26 is disposed along the inner axial surface 24 during the extrusion of the strand 12.

In practice, the ignition enhancer 26 may include any product that is effective to facilitate ignition of the propellant composite. Such ignition enhancers may include, for example, a mixture of aluminum and nitramine fuel. Such nitramine fuels may include cyclotrimethylenetrinitramine (RDX), cyclotetramethylenetetranitramine (HMX) and combinations thereof.

The strand 12 is advantageously sealed adjacent to at least the first lateral end of the strand to further limit the pressure created during combustion of the propellant core and to protect the propellant core 14 from moisture. FIG. 2 is a strand 12 of FIG. 1 including at least a first end seal, generally designated at 32, connected to either the first lateral end 28 or the second lateral end of the strand 12. ). The end seal 32 may be connected to the lateral end of the strand 12 via any suitable technique that provides a seal that restricts moisture penetration into the strand, particularly the propellant core 14. Such techniques include, but are not limited to, ultrasonic welding and / or solvent or adhesive bonds. As shown in FIG. 2, such a technique properly connects the end seal 32 to the plastic sheath 18 at least in position 34. Advantageously, the end seal 32 is connected to the plastic sheath 18 with continuous welding or bonding near the periphery of the plastic sheath.

In practice, the end seal 32 may be formed from a variety of suitable materials that may be connected to the plastic sheath 18 to form a seal against moisture and a pressure resistant seal at the first lateral end of the strand 12. Advantageously, the end seal 24 has the same chemical structure as the plastic sheath 18.

Suitably, the flexible inflator comprises a system in which the associated airbag cushion is inflated uniformly or the inflatable curtain extrudes and directs the inflation gas formed by combustion of the propellant core 14. With reference to FIG. 1, one such system includes a fragile joint 36 extending longitudinally along at least a portion of the plastic sheath 18. Advantageously, at least a portion of the fragile joint 36 is designed to rupture when the internal pressure of the strand 12 resulting from combustion of the propeller core 14 exceeds a predetermined level and the exterior of the plastic sheath 18. Disposed on the axial surface 38. Such brittle joints 36 may include notches 40 formed in the plastic sheath 18. As shown in FIG. 3, when the inflator device 10 is activated to both the plastic sheath 18 and the propellant core 14, the inflation gas generated by combustion of the propellant core 14 causes the expansion of the strands 12 to occur. The propellant core 14 may be appropriately ruptured adjacent to the brittle junction 36 so as to be substantially released along its total length.

Referring now to FIG. 4, there is shown a flexible inflator device in accordance with another preferred embodiment of the present invention, generally designated 110. The flexible inflator 110 includes a propellant containing strand 112 comprising an externally coextruded plastic sheath 18 and an extruded propellant core 114. Advantageously, propellant core 114 includes a central bore 118 extending longitudinally. Suitably, flexible inflator 110 includes a plurality of inflation gas discharge ports 120 spaced at a distance from each other along the length of strand 112 including propellant. As will be appreciated, the inflation gas discharge port 120 is preferably adapted to release or direct the inflation gas generated by combustion of the propellant core 114 to uniformly and effectively inflate relevant inflatable elements such as inflatable curtains or airbag cushions. Play a role. Suitably, the inflation gas discharge port 120 opens when the internal pressure generated by combustion of the propellant core 114 of the strand 112 reaches a specified level, and the weakened area or seal of the plastic sheath 116 is closed. Open when ruptured In one aspect, the inflation gas discharge port 120 may extend through at least a portion of the thickness of the plastic sheath 116 and form the outer axial surface 122 of the strand 112 such that a weak and rupturable zone is formed.

Advantageously, the center bore 118 may include a connected side channel 124 corresponding to the inflation gas discharge port 120. Such a channel acts to direct the expansion gas towards the expansion gas discharge port 120 by facilitating the release of the expansion gas along the length of the strand and the bursting of the plastic sheath 116 in the region corresponding to the expansion gas port 120. can do.

Inflator device 110 may also include a metallized outer layer 126. Such metallized outer layer 126 may serve to protect the strand 112 from premature rupture or cracking of the plastic sheath 116, as well as provide additional pressure resistance and moisture barrier properties. According to one preferred embodiment of the present invention, the metallized outer layer 126 is steam disposed in an outer vicinity of the outer axial surface 128 of the plastic sheath 116. However, guided by the teachings provided herein and those skilled in the art, the broader implementation of the invention need not necessarily be limited to other suitable ways in which, for example, metallized outer layers can be combined or merged to be used. I will understand that.

Referring now again to FIG. 5, a preferred embodiment in connection with the present invention is a fusible expander, generally designated 210, with reference numeral 212 disposed inside a flexible housing, generally designated 214. It is shown to include a plurality of propellant-containing strands as shown generally. As shown in FIG. 5, each strand 212 includes a longitudinal center bore 220 extending through the length of the strand 212 and a propellant core 216 coextruded with the plastic sheath 218. Ignition enhancer 222 may be disposed on at least a portion of inner axial surface 224 of central bore 220. Although FIG. 5 shows seven strands 212 disposed inside flexible housing 214, those skilled in the art and guided by the teachings provided herein and disposed within flexible housing 214 are skilled in the art. It will be appreciated that the number of strands 212 can vary depending on the desired performance and / or expansion gas output.

Indeed, the flexible housing 214 extends through at least a portion of the thickness of the flexible housing 214 forming a weakened region in the housing and is formed on the outer axial surface 228 of the flexible housing 214. Gas discharge port 226 is suitably included. Suitably, the inflation gas discharge port 226 has a weakened area of the housing 214 corresponding to the port 226 due to the pressure generated by the generation of inflation gas during combustion of the propellant core 216 of the strand 212. Open when ruptured. Advantageously, the inflation gas discharge port 226 serves to direct the inflation gas along the length of the flexible inflator to uniformly fill the associated airbag cushion or inflatable curtain.

Referring now to FIG. 6, a flexible expander according to any preferred embodiment of the present invention, generally designated by reference numeral 310, as implemented within an expansion assembly disposed inside a vehicle and designated generally by reference 312. Shown. Flexible inflator 310 may be used in inflation assembly 312 to inflate at least one associated inflatable airbag cushion, such as inflatable curtain 314. Such inflation assembly 310 includes one or more flexible inflators 312 disposed within inflatable curtain 314 that are not folded and unfolded. Indeed, the expansion assembly 312 may be disposed inside the motor vehicle 316, such as along the ceiling contour 318 adjacent to the side window 320, and the flexible expander 310 may be placed inside the arcuate motor vehicle. Is placed.

Therefore, the present invention provides a flexible inflator comprising a propellant core that is protected from moisture absorption by a coextruded flexible plastic sheath forming a moisture barrier. The present invention also provides a gas generating propellant composite applied for co-extrusion with a protective plastic sheath. The present invention also provides a flexible inflator that can be manufactured and / or assembled at reduced cost and in fewer steps. The present invention further provides a fusible expander adapted to fit various contours inside various vehicles. The present invention further provides a flexible inflator comprising a mechanism for promoting effective ignition of the propellant core along the length of the inflator. The present invention further provides a flexible inflator that can be used to effectively and uniformly inflate relevant inflatable airbag cushions, such as inflatable curtain airbag cushions.

Although the flexible inflator of the present invention has particular utility in relation to an inflated assembly that includes an inflatable curtain airbag cushion, such a flexible inflator is useful for all types of inflator assemblies, including occupant, passenger and side impact inflator assemblies. You have to understand. In addition, the propellant compositions of the present invention can be used in many applications that include or require gas generating propellants.

The invention disclosed herein may be suitably practiced without any strands, parts, steps, components not specifically disclosed herein.

In the foregoing Detailed Description, the present invention has been described in terms of numerous purposes for purposes of illustration and in connection with any preferred embodiment, but the invention further allows further embodiments and the specific description set forth herein describes the basic principles of the invention. It will be apparent to those skilled in the art that these can be varied considerably within.

Claims (45)

A flexible inflator comprising a moisture barrier and at least one elongated strand of co-extruded propellant. The flexible inflator of claim 1, wherein the propellant forms an extruded core having an outer axial surface. 3. The flexible expander of claim 2 wherein the moisture barrier is externally coextruded adjacent to the extruded propellant core outer shaft surface. 4. The flexible expander of claim 3 wherein the metallized outer layer is externally vapor deposited adjacent to the outer axial surface of the extruded moisture barrier. 3. The flexible inflator of claim 2 wherein the extruded propellant core includes a longitudinally extending center bore forming an inner axial surface. 6. The flexible inflator of claim 5 wherein the amount of ignition enhancer is disposed along at least a portion of the inner axial surface of the longitudinally extending central bore. 7. The flexible expander of claim 6 wherein at least a portion of the amount of ignition enhancer is disposed along the inner axial surface of the central bore extending longitudinally during extrusion of the strand. 7. The flexible inflator of claim 6 wherein the ignition enhancer comprises a mixture of aluminum and nitramine fuel. The flexible inflator of claim 8, wherein the nitramine fuel comprises cyclotrimethylenetrinitramine. The flexible inflator of claim 1 wherein the moisture barrier includes a fragile joint extending longitudinally along at least a portion of the moisture barrier. The flexible inflator of claim 10 wherein the moisture barrier includes an outer shaft surface and at least a portion of the fragile junction is disposed on the moisture barrier outer shaft surface. 12. The flexible inflator of claim 10 wherein said fragile junction comprises a notch formed in a moisture barrier. The flexible strand of claim 1, wherein the elongated strand has first and second lateral ends disposed oppositely, and the flexible expander further comprises a first end seal connected to at least the first lateral end. Inflator. The flexible inflator of claim 1, wherein the moisture barrier includes an outer shaft surface having a plurality of spaced apart expansion gas release ports. The flexible expander of claim 1, comprising a plurality of elongated strands of moisture barrier and co-extruded propellant, wherein the flexible expander further comprises a flexible housing disposed with a plurality of strands. 16. The flexible inflator of claim 15 wherein the flexible housing includes an outer axial surface having a plurality of spaced apart expansion gas release ports. The flexible inflator of claim 1, wherein the propellant comprises a binder fuel selected from the group consisting of silicone, polybutadie, polyester, polyamide, polyurethane polyacryl, polyacrylamide, and mixtures thereof. An inflatable assembly comprising the flexible inflator of claim 1 and at least one airbag cushion in communication with the inflator. 19. The inflatable assembly of claim 18 wherein the at least one airbag cushion is an inflatable curtain airbag cushion. 19. The expansion assembly of claim 18 wherein the flexible expander is disposed within the motor vehicle and the flexible expander is disposed within the arcuate motor vehicle. A gas generating propellant compound applied for co-extrusion with a plastic sheath, the propellant compound having a binder fuel component effective to impart sufficient adhesive properties and make the composite flexible to adhere the composite and plastic sheath together; A gas generating propellant composite comprising an oxidant. 22. The gas generating propellant composite of claim 21, wherein said binder fuel component comprises the same polymer as the polymer of the plastic sheath. 22. The gas generating propellant composite of claim 21, wherein said binder fuel component comprises a crosslinkable polymer. 22. The gas generating propellant composite of claim 21, further comprising a plasticizer effective to make the binder fuel component flexible. 22. The gas generating propellant composite of claim 21, further comprising a coolant. 22. The gas generating propellant composite of claim 21, further comprising an auxiliary fuel. 22. The gas generating propellant composite of claim 21, further comprising an auxiliary oxidant. A flexible inflator device containing the propellant compound of claim 1 co-extruded with a plastic sheath, An inflation assembly comprising at least one airbag cushion in inflation fluid communication with the inflator. 29. The inflatable assembly of claim 28 wherein said at least one airbag cushion is an inflatable curtain airbag cushion. 29. The expansion assembly of claim 28 wherein the flexible expander device is disposed inside a motor vehicle and the flexible expander device is disposed inside an arcuate motor vehicle. A composite weight ratio binder fuel component of about 5 to about 20 effective to make the composite flexible; An extrudable gas generating propellant composite comprising a composite weight ratio oxidant of about 5 to about 80. 32. The extrudable propellant composite as defined in claim 31, wherein the binder fuel component imparts sufficient adhesive properties to the propellant composite such that the composite adheres to the coextruded plastic sheath. 32. The binder fuel component of claim 31, wherein the binder fuel component comprises a polymer selected from the group consisting of silicone, polybutadine, polyester, polyvinyl chloride, polyamide, polyurethane, polyacryl, polyacrylamide and mixtures thereof. Extrudeable propellant composite. 32. The extrudable propellant composite according to claim 31, wherein said oxidant is selected from the group consisting of alkali, alkaline earth and ammonium nitrates, nitrates and perchlorates, metal oxides, basic metal nitrates, transition metal composites of ammonium nitrate and mixtures thereof. 32. The extrudable propellant composite of claim 31, further comprising a plasticizer in an amount of about 5 to about 30 composite weight ratios effective to solvate the binder fuel component. 32. The extrudable propellant composite according to claim 31, further comprising a coolant in an amount up to a composite weight ratio of about 30. 32. The extrudable propellant composite according to claim 31, further comprising an auxiliary oxidant in an amount up to a composite weight ratio of about 60. 32. The composition of claim 31, wherein the composite weight ratio silicone binder fuel component is from about 5 to about 20, Compound weight ratio of about 5 to about 80 with ammonium perchlorate oxidant An extrudable propellant composite comprising an amount of sodium nitrate auxiliary oxidant effective to obtain an inflation gas comprising up to about 5 parts per million hydrochloric acid. A gas generating propellant compound adapted for coextrusion with a plastic sheath, the propellant compound comprising: A composite weight ratio binder fuel component of about 5 to about 20 effective to make the composite flexible and to impart sufficient adhesive properties to adhere the composite and plastic sheath together; A composite weight ratio oxidant of about 5 to about 80, A propellant composite comprising a composite weight ratio plasticizer of about 5 to about 30, wherein the binder fuel component is selected from the group consisting of polyvinyl chloride, polyester, polyurethane. 40. The propellant compound of claim 39, wherein said oxidant is selected from the group consisting of alkali, alkaline earth and transition metal synthesis of ammonium nitrate, nitrate and perchlorate, metal oxides, basic metal nitrates, ammonium nitrate and mixtures thereof. 40. The propellant composite of claim 39, wherein the plasticizer is selected from the group consisting of dioctyl adipate, dioctyl phthalic acid, dioctyl sebacic and combinations thereof. 40. The propellant formulation of claim 39, further comprising a coolant in an amount up to a composite weight ratio of about 30. 40. The propellant composite of Claim 39, wherein said binder fuel component is a binder fuel component comprising polyester. 40. The composition of claim 39, wherein the composite weight ratio polyvinyl chloride binder fuel component is about 5 to about 20, A composite weight ratio potassium perchlorate oxidant from about 50 to about 80, A propellant composite comprising a composite weight ratio plasticizer of about 5 to about 30. 45. The propellant composite of Claim 44, further comprising a coolant in an amount up to a composite weight ratio of about 30.

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