| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a separator for a nonaqueous secondary battery achieving an excellent balance between air permeability and mechanical strength and causing only a small amount of dust fall, a separator for a nonaqueous secondary battery, and a nonaqueous secondary battery. <P>SOLUTION: When the components of a separator for a nonaqueous secondary battery containing a polypropylene resin and at least one kind of air permeability enhancing agent are heated to 280°C, the air permeability enhancing agent is in a compatible state. The air permeability enhancing agent is precipitated in a nonspherical shape during a temperature drop of the components of the separator for a nonaqueous secondary battery from the compatible state at 280°C to 100°C at -10°C/min. In the process of manufacturing the separator for a nonaqueous secondary battery, the draw ratio at the extrusion into a film is in the range of 50 to 500. The method for manufacturing the separator for a nonaqueous secondary battery includes at least two drawing steps in the film making direction, and the temperature during the second drawing is higher than the temperature during the first drawing. <P>COPYRIGHT: (C)2012,JPO&INPIT |
