Fire retarded aramid fiber-based honeycomb

A honeycomb for use in making aircraft panels wherein said honeycomb has walls comprising a resin-coated paper material that has a self-extinguishing time of less than 10 seconds and a self-extinguishing burn length of less than 12 inches when exposed to a 12 second vertical flame in accordance with the vertical burn test requirements set forth in 14 C.F.R. Part 25.583, said resin-coated paper material comprising:

• a. layer of paper comprising from 30 to 50 weight percent para-aramid fibers and para-aramid pulp, based on the total weight of said paper, and from 50 to 70 weight percent non-aramid fibers and non-aramid pulp, based on the total weight of said paper, said non-aramid fibers being selected from the group consisting of polyester fibers and acrylic fibers and said non-aramid pulp comprising, cellulose fibers;
• and
• a fire retarded phenolic resin comprising a phenol formaldehyde resin and a sufficient amount of a phosphorous-containing fire retardant so that said fire retarded phenolic resin contains from 2 to 6 weight percent phosphorous, wherein the amount of said fire retarded phenolic resin in said resin-coated paper material is sufficient to so that said resin-coated paper material has a self-extinguishing time of less than 10 seconds and a self-extinguishing burn length of less than 12 inches when exposed to a 12-second vertical flame in accordance with the vertical burn test requirements set forth in 14 C.F.R. Part 25.583.