| 摘要 |
PROBLEM TO BE SOLVED: To provide a nonwoven fabric for separation membranes which is different in the density between the front and back surfaces, producible through a process, free of parts of an excessively high density interrupting the permeation of the filtrate water, in the central part of the fabric, and causes no excessive permeation to the back surface when a cast solution is applied to the fabric during manufacture of a separation membrane. SOLUTION: The nonwoven fabric for separation membranes is a spun-bond long-fiber nonwoven fabric and is different in the density between in the front and back surfaces. The density (A) in the part of one half of the thickness from one side surface and the density (B) in the part of the other half of the thickness from the other side surface, in the cross-section of the fabric, meet the condition of A:B=1:0.90 to 1:0.20. There is practically no high-density layer part having a density 2.0 times or higher than the density (A) and no low-density layer part having a density a half or lower than the density (B). COPYRIGHT: (C)2009,JPO&INPIT
|
