| 摘要 |
PURPOSE: To obtain a polyamide ultrafine fiber nonwoven fabric suitable for a liquid filter having a low pressure loss, a battery or a cell separator good in wettability and a lightweight interlining cloth, etc., good in drapeability by melt blowing a polyamide polymer. CONSTITUTION: This polyamide ultrafine fiber nonwoven fabric is obtained by melting a 6-nylon polymer having 1.8-3.0 relative viscosity in a state thereof containing 0.05-1.0% moisture content expressed in terms of mass fraction, discharging the resultant melt at a discharge temperature within the range of (melting point of the polymer +30 deg.C) to (melting point thereof +100 deg.C) so as to provide <=10min residence time into fibers, providing an ultrafine web having 0.5-4.0μm average fiber diameter, <=35% CV% of the fiber diameter and <=0.3 difference in relative viscosity between the fibers and the polymer expressed in terms of absolute value on a collecting unit at 3-25cm distance from a die with an air stream at a temperature of (melting point +30 deg.C) to (melting point +150 deg.C), then applying 0.01-0.3wt.% hydrophilic agent to the web and subsequently carrying out the calendering treatment. The resultant polyamide ultrafine fiber nonwoven fabric has <=5% CV of the basis weight, 0.15-0.80 filling ratio, 1.0-2.5 ratio of the maximum to the average flow rate pore diameters and >=5 cm/30min sucking height of water is obtained. |
