| 摘要 |
PROBLEM TO BE SOLVED: To provide a cylindrical filter having a long filtration life and manufacturable with preferable workability. SOLUTION: This cylindrical filter of the present invention comprises main filtration nonwoven fabric consisting of meltblown nonwoven fabric, and wet nonwoven fabric having an average flow pore diameter larger than the main filtration nonwoven fabric, substantially not fibrillated, manufactured of fibers of a fiber diameter of less than 20μm. The fiber includes ultrafine fibers of a fiber diameter of less than 4μm and bonded adhesive fibers of a fiber diameter of 8-20μm. The cylindrical filter includes auxiliary filtration nonwoven fabric consisting of wet nonwoven fabric with a maximum hole diameter less than twice of the average flow rate hole diameter. The main filtration nonwoven fabric and auxiliary filtration nonwoven fabric are disposed around the porous cylinder in an adjacently layered state. COPYRIGHT: (C)2008,JPO&INPIT
|
