| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a microporous polypropylene film where film formability is improved in accordance with a β-crystal technique which allows microporous films to be continuously produced at a low cost, of which the film specific gravity is further reduced, and which film has significantly high permeability, and to provide a method for producing these microporous polypropylene films. <P>SOLUTION: There is provided a microporous polypropylene film containing in the polypropylene a polypropylene where the relationship between the melt strength (MS) and the melt flow rate (MFR), measured at 230°C, satisfies log(MS)>-0.61 log(MFR)+0.8, and/or the melt strength (MS) measured at 230°C is less than 5 cN and the relationship between the MS and the melt flow rate (MFR) satisfies log(MS)>-0.9 log(MFR)+0.6. <P>COPYRIGHT: (C)2012,JPO&INPIT |
