| 摘要 |
PROBLEM TO BE SOLVED: To provide a filter not forming a large hole and generating no chlorine gas even if exposed to a flame. SOLUTION: Bulky carbon fibers, multicomponent synthetic fibers comprising polymers having different melting points and zero third fibers or a plurality of kinds of third fibers are mixed and entangled and the multicomponent synthetic fibers are thermally fused to the other constitutional fibers to obtain a flame-resistant filter comprising a nonwoven fabric. Pref, curled carbon fibers using coal pitch as a raw material are used and, as the multicomponent synthetic fibers, a core/sheath type composite fiber wherein a sheath comprises a low m.p. polymer and a core comprises a high m.p. polymer is pref. The voids of the nonwoven fabric are desirably set to at least 95%. A suction fan is attached to the flame-resistant filter on a downstream side in a mutually detachable manner to be widely usable as a ventilation fan. |
