To increase a permeation flow rate higher than before while keeping a high particle trapping property in a porous multi-layered hollow fiber membrane having a filtration layer of a porous sheet on the outer surface.
The tube for supports to be provided includes a porous stretched polytetrafluoroethylene tube having an IPA bubble point, which is a substituting property of pore diameter, of 2 to 12 kPa and a large pore diameter and high porosity as high as 75 to 90%. A method of manufacturing the tube for supports involves mixing a liquid-type lubricant with a polytetrafluoroethylene fine powder having a number average molecular weight (Mn) of 1,000,000 to 3,000,000 and extrusion-molding the mixture, or mixing 24 parts or more of an auxiliary agent with a powder having a number average molecular weight (Mn) of 600 to 10,000,000, obtaining a tube by extruding the mixture at a high speed, thereafter, stretching the tube in the axial direction by 20 to 400%, further stretching the tube in the axial direction by 60 to 560% in total stretching ratio of 400 to 700%, and also sintering the tube.
OKUDA TAKETSUGU
KAWABE SHINSUKE
| JP2006007224A | 2006-01-12 | |||
| JPH0431443A | 1992-02-03 | |||
| JP2008119662A | 2008-05-29 | |||
| JPH09263611A | 1997-10-07 |
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