Flame resistant fabric for aviation airbags

Abstract

A flame resistant fabric for the use in the construction of aviation airbags comprises a polyester fiber substrate which is treated with a first flame retardant. A polyurethane coating is applied to the polyester fiber substrate, which has been treated with the first flame retardant, to impart high pressure permeability resistance to the flame resistant fabric. The polyurethane coating comprises a second flame retardant to insure that the flame resistant fabric complies with Federal Aviation Requirement 25.853. The flame resistant fabric further comprises 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 fabric for the construction of an airbag for installation in an aircraft, said fabric comprising: a high tenacity continuous polyester filament yarn, said high tenacity continuous polyester filament yarn comprising: a 500 denier-96 filament polyester fiber substrate; and an amount of phosphate-phosphonate compound in a range of about 0.1%-0.3% by weight; a plain weave utilizing said high tenacity continuous polyester filament yarn, characterized by a count of 49-53 per inch by 49-53 per inch, said plain weave having a first fabric side and a second fabric side, where said plain weave has been heat set to between 340 degrees Fahrenheit to 420 degrees Fahrenheit for a period of time of about 30 to 60 seconds; and a composition comprising polyurethane with flame retardant additives, said composition applied as a coating to the first fabric side and the second fabric side at a coating weight of between 25-50 grams per square meter; wherein said fabric, when subjected to aviation vertical flammability requirements, is 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; and is further characterized as exhibiting 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.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) For a fuller understanding of the nature of the present invention, reference should be had to the following detailed description taken in connection with the accompanying drawings in which:

(2) FIG. 1 presents a table illustrative of the results of vertical flammability testing in accordance with FAR 25.853 for a silicone coated nylon fabric;

(3) FIG. 2 presents a table illustrative of the results of vertical flammability testing in accordance with FAR 25.853 for an uncoated flame resistant polyester fabric;

(4) FIG. 3 presents a table illustrative of the results of vertical flammability testing in accordance with FAR 25.853 for a flame resistant polyester fabric coated with a flame retardant polyurethane in accordance with the present invention;

(5) FIG. 4 presents a table illustrative of the results of high pressure air permeability testing for a flame resistant polyester fabric coated with a flame resistant polyurethane in accordance with the present invention; and

(6) FIG. 5 presents a table illustrative of the results of high pressure air permeability testing for a flame resistant polyester fabric coated with a flame resistant polyurethane in accordance with the present invention.

DETAILED DESCRIPTION

(7) As stated above the present invention is directed to a flame resistant fabric for use in constructing components of an aircraft. In at least one embodiment, the present invention is directed to a flame resistant fabric for the construction of aviation airbags.

(8) At the present time the Federal Aviation Administration (“FAA”) of the United States of America has issued a number of Federal Aviation Requirements (“FAR”) directed to various aspects of aircraft construction and operation. Among these requirements is Federal Aviation Administration FAR 25.853 which includes, among other things, vertical flammability requirements for materials used in many aircraft operated in the United States. More in particular, in accordance with FAR 25.853 a material for use in aircraft in the United States must meet vertical flammability requirements which include, a flame time which is not to exceed fifteen seconds, a burn length, which is not to exceed eight inches, and a drip flame which is not to exceed five seconds.

(9) Once again, as stated above, at the present time there are no fabrics known which meet the stringent requirements of FAR 25.853 for vertical flammability which may utilized for construction of aviation airbags in aircraft operated in the United States. As such, the FAA has indefinitely waived this requirement provided that any fabric utilized for aviation airbags is sufficiently flame resistant to pass the less stringent requirements of a horizontal flame test in accordance with the Federal Motor Vehicle Safety Standard 302.

(10) The table presented in FIG. 1 is illustrative of the results obtained for a nylon fabric which is coated with 30 grams per square meter (“gsm”) of liquid silicone rubber, as is typical for use in airbag fabrics utilized in automobiles in the United States, when the fabric is subjected to vertical flammability testing in accordance with FAR 25.853. As is readily apparent from the results presented in FIG. 1, a nylon fabric coated with liquid silicone rubber fails to meet the requirements for vertical flammability resistance under 25.853. In accordance with at least one embodiment of the present invention, a flame resistant fabric for aviation airbags comprises the uncoated polyester fiber. In at least one further embodiment, a flame resistant fabric in accordance with the present invention comprises a plurality of 500 denier-96 filament polyester fibers. In yet one further embodiment, the plurality of polyester fibers of the flame resistant fabric of the present invention are woven into a plain weave pattern at a count in a range of about 49 to 53 fibers per inch by about 49 to 53 fibers per inch.

(11) A flame resistant fabric in accordance with one embodiment of the present invention comprises a polyester fiber which has been treated with a flame retardant. In at least one embodiment, a flame resistant fabric comprises a polyester fiber substrate that has been rendered flame retardant by treatment with a phosphate-phosphonate compound having a low volatility and a high phosphorous content. In yet one further embodiment, the polyester fibers comprise an amount of the phosphate-phosphonate compound in a range of about 0.1%-0.3% by weight with respect to the weight of the polyester fiber.

(12) In yet one further embodiment of a flame resistant fabric for aviation airbags in accordance with the present invention, a polyester fiber that has been treated with a phosphate-phosphonate compound and woven into a plain weave pattern, such as, but not limited to a count of 49-53 per inch by 49-53 per inch, is subsequently heat set to impart dimensional stability, as well as to control air permeability. In at least one embodiment, heat setting the polyester fiber comprises exposing the woven polyester fiber to temperatures in a range of about 340 degrees Fahrenheit to 420 degrees Fahrenheit for a period of time of about 30 to 60 seconds.

(13) A flame resistant fabric for aviation airbags in accordance with at least one further embodiment of the present invention comprises a polyester fiber which has been treated with a phosphate-phosphonate compound, such as disclosed above, which is then further coated with polyurethane. In at least one further embodiment, a polyester fiber is coated with a polyurethane that includes a 1:3 flame retardant mixture of antimony trioxide:1,1′-(ethane-1,3-diyl)bis[pentabromobenzene]. In particular, the flame retardant polyurethane coating acts as an effective char former to inhibit flame spread during the course of a vertical flammability test, for example, a vertical flammability test in accordance with FAR 25.853.

(14) Turn next to FIG. 2, the table therein illustrates that a flame retardant polyester fabric prepared in accordance with the present invention as disclosed herein comprises sufficient flame retardant properties which allow it to pass the stringent vertical flammability requirements under FAR 25.853.

(15) Furthermore, and with reference to FIG. 3, a flame retardant polyester fabric prepared in accordance with the present invention as disclosed herein and further coated with a flame resistant polyurethane also exhibits flame resistant properties sufficient for the material to pass the vertical flammability requirements of FAR 25.853.

(16) The application of a polyurethane coating as disclosed above assures a high pressure permeability resistance of the coated flame retardant polyester fibers. However, as is known, a polyurethane coating in and of itself increases the flammability of the material which is coated. As such, in accordance with one embodiment of the present invention, a polyurethane coating comprises a flame retardant. In at least one embodiment, a polyurethane coating in accordance with the present invention comprises a flame retardant mixture of antimony trioxide and 1,1′-(ethane-1,3-diyl)bis[pentabromobenzene], and in at least one further embodiment, a polyurethane coating comprises a mixture of about one part of antimony trioxide to about three parts of 1,1′-(ethane-1,3-diyl)bis[pentabromobenzene].

(17) 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.

(18) The tables presented in FIGS. 4 and 5 demonstrate that a flame retardant polyurethane coating further assures high pressure permeability resistance to the flame retardant polyester fibers prepared in accordance with the present invention as disclosed herein.

(19) Since many modifications, variations and changes in detail can be made to the described embodiment 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.

(20) Now that the invention has been described,