METHOD OF MAKING A FLAME RESISTANT AIRBAG SUITABLE FOR USE IN AVIATION APPLICATIONS

Abstract

A method of making a flame resistant airbag suitable for use in aviation applications is discussed. A flame resistant fabric for the use in the construction of aviation airbags is woven from a high tenacity continuous polyester fiber substrate. A polyurethane coating is applied to the woven fabric, which has been treated with a flame retardant, to impart high pressure permeability resistance to the flame resistant fabric. The resulting fabric complies with Federal Aviation Requirement 25.853 as well as exhibits sufficient high pressure permeability resistance which is measured as a pressure of not less than about 198 kPa after five seconds from an initial inflation and pressurization to about 200 kPa, such as may be encountered in and during an inflation of aviation airbag assemblies.

Claims

1. A method of making a flame resistant fabric suitable for use in the construction of airbags for aviation applications, said method comprising the steps of: providing a high tenacity continuous polyester filament yarn, said high tenacity continuous polyester filament yarn having a polyester fiber substrate and a phosphate-phosphonate compound; weaving said high tenacity continuous polyester filament yarn into a plain weave pattern fabric; heat setting said plain weave pattern fabric; coating said plain weave pattern fabric with a coating composition; and testing said plain weave pattern fabric against aviation-specific performance requirements.

2. The method of claim 1, where said high tenacity continuous polyester filament yarn has a 500 to 600 denier-90 to 100 filament polyester film substrate.

3. The method of claim 1, where said high tenacity continuous polyester filament yarn has phosphorous levels in the range of 3000 to 7000 ppm.

4. The method of claim 1, where said high tenacity continuous polyester filament yarn has phosphorous levels in the range of 1000 to 3000 ppm.

5. The method of claim 1, where said high tenacity continuous polyester filament yarn has a tenacity of at least 3 to 7 grams per denier.

6. The method of claim 1, where said high tenacity continuous polyester filament yarn is woven into said plain weave on a water jet loom where the filling yarn and the warp yarn are the same said high tenacity continuous polyester filament yarn.

7. The method of claim 1, where said heat setting occurs between 340 degrees Fahrenheit to 420 degrees Fahrenheit for a period of time of about 30 to 60 seconds.

8. The method of claim 1, where said heat setting is performed on a pin tenter that shrinks and sets said fabric to 45-53 ends and 45-53 picks.

9. The method of claim 1, further comprising the steps of: providing a coating composition comprising polyurethane with flame retardant additives; and applying said coating composition to said heat set plain weave pattern fabric to achieve a coat weight of between 25-50 grams per square meter.

10. The method of claim 1, where said aviation-specific performance requirements include vertical flammability requirements that are characterized as: being self-extinguishing; having an average burn length not exceeding 8 inches; having an average flame time after removal of the flame source not exceeding 15 seconds; and having drippings that do not continue to flame for more than 5 seconds after falling.

11. The method of claim 1, where said aviation-specific performance requirements include a high pressure permeability resistance characterized as a pressure of not less than 198 kPa after five seconds from an initial inflation and pressurization to 200 kPa.

12. An airbag made using the flame resistant fabric resulting from the process of claim 1.

13. A method of making a flame resistant airbag suitable for use in aviation applications, said method comprising the steps of: providing a fabric, said fabric comprising a plurality of high tenacity continuous polyester filament yarn woven into a plain weave pattern characterized by a count of 49-53 per inch by 49-53 per inch; heat setting said fabric to between 340 degrees Fahrenheit to 420 degrees Fahrenheit for a period of time of about 30 to 60 seconds; providing a coating composition, said coating composition comprising a flame retardant and a polyurethane; applying said coating composition to the fabric to achieve a coat weight of between 25-50 grams per square meter; and constructing an airbag utilizing said fabric, whereby said airbag exhibits a high pressure permeability resistance characterized as a pressure of not less than 198 kPa after five seconds from an initial inflation and pressurization to 200 kPa, as well as, vertical flammability performance characterized as: being self-extinguishing; having an average burn length not exceeding 8 inches; having an average flame time after removal of the flame source not exceeding 15 seconds; and having drippings that do not continue to flame for more than 5 seconds after falling.

14. The method of claim 13 where said high tenacity continuous polyester filament yarn has a 500 to 600 denier-90 to 100 filament polyester film substrate.

15. The method of claim 13 where said high tenacity continuous polyester filament yarn has phosphorous levels in the range of 3000 to 7000 ppm.

16. The method of claim 13, where said high tenacity continuous polyester filament yarn has phosphorous levels in the range of 1000 to 3000 ppm.

17. The method of claim 13, where said high tenacity continuous polyester filament yarn has a tenacity of at least 3 to 7 grams per denier.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where:

[0031] FIG. 1 shows samples of current automotive airbag fabrics and the fabric made by the claimed method, after being subjected to the FAA′ vertical bur test.

DESCRIPTION

[0032] In the Summary of the Invention above, in the Description and appended Claims below, and in the accompanying drawings, reference is made to particular features of the invention. It is to be understood that the disclosure of the invention in this specification includes all possible combinations of such particular features. For example, where a particular feature is disclosed in the context of a particular aspect or embodiment of the invention, or a particular claim, that feature can also be used, to the extent possible, in combination with and/or in the context of other particular aspects and embodiments of the invention, and in the invention generally.

[0033] The term “comprises” and grammatical equivalents thereof are used herein to mean that other components, ingredients, steps, etc. are optionally present. For example, an article “comprising” (or “which comprises”) components A, B, and C can consist of (i.e., contain only) components A, B, and C, or can contain not only components A, B, and C but also one or more other components.

[0034] The term “at least” followed by a number is used herein to denote the start of a range beginning with that number (which may be a range having an upper limit or no upper limit, depending on the variable being defined). For example “at least 1” means 1 or more than 1. The term “at most” followed by a number is used herein to denote the end of a range ending with that number (which may be a range having 1 or 0 as its lower limit, or a range having no lower limit, depending upon the variable being defined). For example, “at most 4” means 4 or less than 4, and “at most 40%” means 40% or less than 40%. When, in this specification, a range is given as “(a first number) to (a second number)” or “(a first number)-(a second number),” this means a range whose lower limit is the first number and whose upper limit is the second number. For example, 25 to 100 mm means a range whose lower limit is 25 mm, and whose upper limit is 100 mm.

[0035] While the specification will conclude with claims defining the features of embodiments of the invention that are regarded as novel, it is believed that the invention will be better understood from a consideration of the following description in conjunction with the figures, in which like reference numerals are carried forward.

[0036] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein. Specifically, component names, types, and values, as depicted in the exemplary schematic diagrams, are not intended to limit the scope of the present invention and are presented only as possible embodiments.

[0037] As stated above, the present invention is directed to methods of making flame resistant fabric for use in constructing airbags for installation and use an aircraft.

[0038] In a preferred embodiment, a method of making a flame resistant fabric suitable for use in the construction of airbags for aviation applications begins with providing a high tenacity continuous polyester filament yarn. The high tenacity continuous polyester filament yarn preferably has a polyester fiber substrate and a phosphate-phosphonate compound. Air bag fabrics require high tenacity continuous filament yarn to achieve the strength properties required for performance.

[0039] Other flame resistant fabrics in the art utilize fibers as opposed to continuous filaments. The addition of components such as this dramatically reduces the strength of the yarn due to the disruption and molecular alignment of the polymer chain by the introduction of the fibers. The use of the continuous filament yarn, as disclosed here, avoids the disruption of the continuity of the polymer chain and alignment of the polymer chains created by the impact on the chain length and crystallization impacted by the use of fiber additives as is currently known in the art.

[0040] The high tenacity continuous polyester filament yarn is woven into a plain weave pattern fabric and heat set.

[0041] The heat set fabric is then coated with a coating composition and tested against aviation-specific performance requirements.

[0042] In embodiments, the high tenacity continuous polyester filament yarn may also have a 500 to 600 denier-90 to 100 filament polyester film substrate and phosphorous levels in the range of 1000 to 7000 ppm. The yarn is also characterized as having a tenacity of at least 3 to 7 grams per denier.

[0043] In a preferred embodiment, the high tenacity continuous polyester filament yarn is optimally a 560 denier, 96 filament polyester yarn with a phosphorous level of 5200-6500 ppm and a tenacity of 6.5 grams per denier.

[0044] The yarn is woven into a plain weave on a water jet loom where the filling yarn and the warp yarn are the same said high tenacity continuous polyester filament yarn.

[0045] The woven fabric is dried via heat setting, where said heat setting occurs between 340 degrees Fahrenheit to 420 degrees Fahrenheit for a period of time of about 30 to 60 seconds. The heat setting is performed on a pin tenter that shrinks and sets said fabric to 45-53 ends and 45-53 picks.

[0046] The heat set fabric is now dimensionally stable but does not yet meet the air permeability requirements for an aviation airbag. A coating composition comprising polyurethane with flame retardant additives is then applied to achieve a coat weight of between 25-50 grams per square meter.

[0047] The resultant fabric can now be cut and sewn as required to form an airbag that meets both the flammability and air permeability performance requirements for an aviation airbag.

[0048] In yet another embodiment, a flame resistant fabric in accordance with the present invention having a polyester fiber which is treated with a phosphate-phosphonate compound and subsequently heat set and is then coated with a flame retardant polyurethane exhibits a high pressure permeability resistance which is measured as a pressure of not less than about 198 kPa after five seconds from an initial inflation and pressurization to about 200 kPa, such as may be encountered in and during an inflation of aviation airbag assemblies.

[0049] Since many modifications, variations and changes in detail can be made to the described embodiments of the invention, it is intended that all matters in the foregoing description and shown in the accompanying figures be interpreted as illustrative and not in a limiting sense. Thus, the scope of the invention should be determined by the appended claims and their legal equivalents.

[0050] It will be appreciated that the methods, processes, devices, apparatus, and systems described above are set forth by way of example and not of limitation. Numerous variations, additions, omissions, and other modifications will be apparent to one of ordinary skill in the art.

[0051] While particular embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that various changes and modifications in form and details may be made therein without departing from the spirit and scope of the invention as defined by the following claims. The claims that follow are intended to include all such variations and modifications that might fall within their scope, and should be interpreted in the broadest sense allowable by law.

[0052] In light of the foregoing description, it should be recognized that embodiments in accordance with the present invention can be realized in numerous configurations contemplated to be within the scope and spirit of the claims. Additionally, the description above is intended by way of example only and is not intended to limit the present invention in any way, except as set forth in the claims.