摘要 |
A filtration filter including a cartridge, which contains a crystalline polymer microporous membrane having a plurality of pores, where the average pore diameter of a first surface of the crystalline polymer microporous membrane is larger than that of a second surface thereof, and the average pore diameter of the crystalline polymer microporous membrane continuously changes from the first surface thereof to the second surface thereof, wherein at least part of the crystalline polymer microporous membrane forming the cartridge is subjected to surface modification after the crystalline polymer microporous membrane is formed into the cartridge.
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