Method of making a flame resistant airbag suitable for use in aviation applications
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.
1. A method of making a flame resistant aviation airbag suitable for use in 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;
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 onto said fabric and 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 aviation airbag utilizing said fabric, whereby said aviation 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, and adequately conforms pursuant to Federal Aviation Requirements 25.853 which is characterized as:
being self-extinguishing when tested vertically in accordance with Federal Aviation Requirement 25.853, Appendix F, Part I (b)(4) or other equivalent means;
having an average burn length not exceeding 8 inches when tested vertically in accordance with Federal Aviation Requirement 25.853, Appendix F, Part I (b)(4) or other equivalent means;
having an average flame time after removal of the flame source not exceeding 15 seconds when tested vertically in accordance with Federal Aviation Requirement 25.853, Appendix F, Part I (b)(4) or other equivalent means; and
having drippings that do not continue to flame for more than 5 seconds after falling when tested vertically in accordance with Federal Aviation Requirement 25.853, Appendix F, Part I (b)(4) or other equivalent means.
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 is performed on a pin tenter that shrinks and sets said fabric to 45-53 ends and 45-53 picks.