| 摘要 |
PROBLEM TO BE SOLVED: To provide a filter base material that has an excellent pleating characteristic, excellent capability of preserving pleat configuration, and durability at the same time while maintaining a filtration capacity, and a filter employing the same.SOLUTION: The filter base material is constituted of a nonwoven fabric which is formed of a long fiber of birefringence of 0.04 to 0.09 and fineness of 1 to 5 dtex composed of a polyester (component A) of a glass transition temperature of not lower than 60°C as the main component and a small amount of a thermoplastic resin (component B) of a glass transition temperature of from 120 to 160°C incompatible with the main component, has an apparent density of 0.30 to 0.60 g/cm, a basis weight of 150 to 400 g/m, bending resistance in the longitudinal direction of 25 to 60 mN, tensile strength retention of 70 to 100% after 10,000 times of bending by a MIT bending test, and heat shrinkage in a dry state at 180°C of not higher than 5%, and is not subjected to an entangling treatment; wherein the efficiency of collecting particles not smaller than 0.3 μm and not greater than 0.5 μm is not lower than 25% and the QF value is not lower than 0.03 mmAq. The filter employs the filter base material. |
