| 摘要 |
PROBLEM TO BE SOLVED: To easily form a nonwoven fiber aggregate and to obtain a heat- resistant filter material having excellent heat resistance and chemical stability by constituting the nonwoven fiber aggregate of a mixture of a polytetrafluoroethylene fiber and an aromatic polyimide fiber. SOLUTION: This heat-resistant filter material consists of a base cloth 1 comprising a woven fabric produced by plain weaving of glass fiber multifilament, and a pair of nonwoven fiber aggregates 2, 3 laminated on both surfaces of the base cloth 1 entangled and integrated by needling. The glass fiber multifilament which constitute the base cloth 1 are coated with a polytetrafluoroethylene resin so as to suppress damages during needling. The nonwoven fiber aggregates 2, 3 consist of a mixture of polytetrafluoroethylene fiber and an aromatic polyimide fiber. The compounding proportions of the polytetrafluoroethylene fiber and the aromatic polyimide fiber are preferably controlled to about 60 to 90 wt.% and about 5 to 40 wt.%, respectively. |
