| 摘要 |
PROBLEM TO BE SOLVED: To provide a cylindrical filter having a high filtration speed and a long filtration life. SOLUTION: The cylindrical filter is a cylindrical filter obtained by rolling filter mediums on the circumference of a porous cylinder, wherein as the filter mediums a filter medium A made of an anti-static nonwoven fabric and a filter medium B selected from a group consisting of a melt blow type nonwoven fabric, a spun-bond type nonwoven fabric, and wet nonwoven fabric are rolled and the filter medium A is rolled downstream of the filter medium B in the flow direction of a filtrate. The fragile ventilation rate of the anti-static nonwoven fabric is 10 cm<SP>3</SP>/cm<SP>2</SP>/sec or lower per 15 g/m<SP>2</SP>weight basis. COPYRIGHT: (C)2007,JPO&INPIT
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