POLYIMIDE FIBER MASS, SOUND ABSORBING MATERIAL, HEAT INSULATION MATERIAL, FLAME-RETARDANT MAT, FILTER CLOTH, HEAT-RESISTANT CLOTHING, NONWOVEN FABRIC, HEAT INSULATION/SOUND ABSORBING MATERIAL FOR AIRCRAFT, AND HEAT-RESISTANT BAG FILTER

摘要

A polyimide fiber assembly of the present invention includes polyimide fibers having curved shapes with an average fiber diameter falling within a range of greater than 1 µm to not greater than 100 µm, the polyimide fiber assembly having a bulk density falling within a range of not less than 1 kg/m 3 to not greater than 30 kg/m 3 . This makes it possible to realize a polyimide fiber assembly that is both excellent in thermal insulation performance and sound absorbency and light in weight. The polyimide fiber assembly of the present invention can be obtained by a production method comprising the steps of: (i) discharging a polymeric resin solution obtained by dissolving polyamic acid or polyimide in an organic solvent; and (ii) using external force to cause the polymeric resin solution thus discharged to fly in a direction of the external force, the external force being external force of gas from a direction intersecting with a discharge direction in which the polymeric resin solution is discharged, and then forming a polymeric resin into fibers by spinning while vaporizing the organic solvent contained in the polymeric resin solution.