REINFORCED THERMOPLASTIC ARTICLES, COMPOSITIONS FOR THE MANUFACTURE OF THE ARTICLES, METHODS OF MANUFACTURE, AND ARTICLES FORMED THEREFROM

1 . A composition for the manufacture of a porous, compressible article, the composition comprising a combination of:

a plurality of reinforcing fibers;

a plurality of polyimide fibers; and

a plurality of polymeric binder fibers;

wherein the polymeric binder fibers have a melting point lower than the polyimide fibers.

2 . The composition of claim 1 , comprising:

from 30 to 65 wt. % of the reinforcing fibers;

from 30 to 65 wt. % of the polyimide fibers; and

from 2 to 20 wt. % of the polymeric binder fibers, each based on the combined weight of the reinforcing fibers, the polyimide fibers, and the polymeric binder fibers.

3 . The composition of claim 1 , wherein the plurality of reinforcing fibers comprise metal fibers, metallized inorganic fibers, metallized synthetic fibers, glass fibers, graphite fibers, carbon fibers, ceramic fibers, mineral fibers, basalt fibers, polymer fibers having a melt temperature at least 150° C. higher than the polyimide, or a combination thereof.

4 . The composition of claim 1 , wherein the reinforcing fibers comprise glass fibers.

5 . The composition of claim 1 , wherein the polyimide comprises a polyetherimide.

6 . The composition of claim 1 , wherein the polymeric binder comprises a polysiloxane, polysiloxane-polyestercarbonate copolymer, polyester, polyester-polyetherimide blend, bicomponent fiber of any of the foregoing, or a combination thereof.

7 . The composition of claim 6 , wherein the polysiloxane-polyestercarbonate copolymer comprises

polysiloxane units comprising from 4 to 50 siloxane units, wherein the siloxane units are present in an amount of 0.2 to 10 wt % of the total weight of the polysiloxane-polyestercarbonate copolymer, and

polyester-polycarbonate units comprising, based on the polyester-polycarbonate units

from 50 to 100 mole percent of arylate ester units,

from more than 0 to less than 50 mole percent aromatic carbonate units,

from more than 0 to less than 30 mole percent resorcinol carbonate units, and

from more than 0 to less than 35 mole percent bisphenol carbonate units; and

wherein the polysiloxane-polyestercarbonate copolymer composition has a 2 minute integrated heat release rate of less than or equal to 65 kilowatt-minutes per square meter (kW-min/m 2 ) and a peak heat release rate of less than 65 kilowatts per square meter (kW/m 2 ) as measured using the method of FAR F25.4, in accordance with Federal Aviation Regulation FAR 25.853 (d).

8 . The composition of claim 7 , wherein the arylate ester units are isophthalate-terephthalate-resorcinol ester units.

9 . The composition of claim 1 , wherein

the average fiber length of the reinforcing fibers is from 5 to 75 millimeters and the average fiber diameter of the reinforcing fibers is from 5 to 125 micrometers;

the average fiber length of the polyimide fibers is from 5 to 75 millimeters, and the average fiber diameter of the polyimide fibers is from 5 to 125 micrometers; and

the average fiber length of the polymeric binder fibers is from 2 millimeters to 5 millimeters, and the average fiber diameter of the polymeric binder fibers is from 5 to 50 micrometers.

10 . The composition of claim 1 , further comprising an aqueous solvent.

11 . A method for forming a porous article, the method comprising:

forming a layer comprising a suspension of the composition of claim 1 in liquid;

at least partially removing the liquid from the suspension to form a web;

heating the web under conditions sufficient to remove any remaining liquid from the web and to melt the polymeric binder fibers but not the polyimide; and

cooling the heated web to form the porous mat, wherein the porous article comprises a network of the reinforcing fibers and the polyimide fibers in a matrix of the polymeric binder.

12 . The method of claim 11 , wherein forming the web comprises

depositing the composition dispersed in an aqueous suspension onto a forming support element to form the layer; and

evacuating the aqueous solvent to form the web.

13 . The method of claim 12 , wherein the heating is at a temperature from 130 to 170° C.

14 . The method of claim 13 , wherein the heating comprises heating in an oven at a temperature from 130 to 150° C., then infrared heating at a temperature from 150 to 170° C.

15 . A porous article comprising:

a network of a plurality of reinforcing fibers and a plurality of polyimide fibers; and

a matrix deposited on the network comprising melted and cooled polymeric binder fibers, wherein the polymeric binder has a melt temperature lower than the polyimide fibers.

16 . The porous article of claim 15 , having an areal weight of from 90 to 500 g/m 2 .

17 . A method of forming a dual matrix composite, the method comprising:

heating and compressing at least one of the porous articles of claim 9 disposed on a carrier layer under conditions sufficient to melt the polyimide fibers and consolidate the network;

cooling the heated, compressed article and carrier layer under pressure to form the dual matrix composite comprising

a network comprising a plurality of reinforcing fibers; and

a matrix comprising melted and cooled polyimide fibers and melted and cooled polymeric binder fibers, wherein the polymeric binder has a melt temperature lower than the polyimide.

18 . The method of claim 17 , comprising heating and compressing a stack comprising two or more of the porous mats.

19 . The method of claim 18 , comprising heating and compressing a stack comprising two to ten of the porous mats.

20 . A dual matrix, thermoformable composite, comprising:

a network comprising a plurality of reinforcing fibers; and

a matrix comprising melted and cooled polyimide fibers and melted and cooled polymeric binder fibers, wherein the polymeric binder has a melt temperature lower than the polyimide, and

wherein the dual matrix composite has a minimum degree of loft of greater than or equal to three.

21 . The dual matrix composite of claim 20 , wherein the loft of the dual matrix composite is within one sigma, over the entirety of the dual matrix composite.

22 . The dual matrix composite of claim 20 , wherein the loft of the dual matrix composite is within 30%, over the entirety of the dual matrix composite.

23 . The dual matrix composite of claim 20 , having a porosity that is less than about 4 volume % of the porosity of the porous article.

24 . The dual matrix composite of claim 20 , having a melting point of at least 205° C.

25 . The dual matrix composition of claim 20 , wherein a thermoformed article made from the dual matrix composite has:

a peak heat release of less than 65 kW/m 2 , as measured by FAR 25.853 (OSU test);

a total heat release at 2 minutes of less than or equal to 65 kW*min/m 2 as measured by FAR 25.853 (OSU test); and

an NBS optical smoke density of less than 200 when measured at 4 minutes, based on ASTM E-662 (FAR/JAR 25.853).

26 . The dual matrix composite of claim 20 , further having a toxic gases release of less than or equal to 100 ppm based on Draeger Tube Toxicity test (Airbus ABD0031, Boeing BSS 7239).

27 . The dual matrix composite of claim 20 , wherein the dual matrix composite does not include a flame retardant, wherein the flame retardant is a perfluoroalkyl sulfonate salt, a fluoropolymer encapsulated vinylaromatic copolymer, potassium diphenylsulfone-3-sulfonate, sodium trichlorobenzenesulfonate, or a combination comprising at least one of the foregoing flame retardants.

28 . The dual matrix composite of claim 20 , further comprising a thermal stabilizer, an antioxidant, a light stabilizer, a gamma-irradiation stabilizer, a colorant, an antistatic agent, a lubricant, a mold release agent, or a combination thereof.

29 . A method of forming an article, the method comprising:

thermoforming the dual matrix composite of claim 20 to form the article.

30 . The method of claim 29 , wherein the thermoforming is match metal thermoforming.

31 . An article, comprising:

a thermoformed dual matrix composite of claim 20 .

32 . The article of claim 31 , having a porosity from 30 to 75 volume % less than the porosity of the dual matrix composite.

33 . The article of claim 32 , in the form of an aircraft interior panel.

34 . A dual matrix composite, comprising:

a network comprising a plurality of reinforcing fibers selected from metal fibers, metallized inorganic fibers, metallized synthetic fibers, glass fibers, graphite fibers, carbon fibers, ceramic fibers, mineral fibers, basalt fibers, polymer fibers having a melt temperature at least 150° C. higher than the polyimide, and combinations thereof; and

a matrix comprising (a) melted and cooled polyimide fibers and (b) melted and cooled polymeric binder fibers, wherein the polymeric binder has a melt temperature lower than the polyimide, and

wherein the dual matrix composite has a minimum degree of loft of greater than or equal to three and the loft of the dual matrix composite is within 30% over the entirety of the dual matrix composite.

35 . An article comprising a thermoformed dual matrix composite of claim 34 , wherein the composite exhibits

a time to peak release, as measured by FAR 25.853 (OSU test),

a 2 minute total heat release as measured by FAR 25.853 (OSU test), and

an NBS optical smoke density of less than 200 at 4 minutes, determined in accordance with ASTM E-662 (FAR/JAR 25.853).

36 . The article of claim 35 , wherein the dual matrix composite does not include a flame retardant, wherein the flame retardant is a perfluoroalkyl sulfonate salt, a fluoropolymer encapsulated vinylaromatic copolymer, potassium diphenylsulfone-3-sulfonate, sodium trichlorobenzenesulfonate, or a combination comprising at least one of the foregoing flame retardants.