Patent ID: 9721728
Date: 2017-08-01
CPC Classifications: B29C,B29K,B32B,C08J,H01G

Claim:
1. A biaxially orientated polypropylene film comprising protrusions on both surfaces thereof, the biaxially orientated polypropylene film having a thickness (t1) of 1 to 3 μm, having a ten point average roughness (SRz) of 50 nm or more and less than 500 nm on both surfaces, and meeting equations (1) and (2) where one surface and another surface are referred to as a surface A and a surface B, respectively: wherein Pa denotes number of protrusions per 0.1 mm 2 on the surface A and Pb denotes number of protrusions per 0.1 mm 2 on the surface B, wherein the biaxially orientated polypropylene film meets both of equations (3) and (4): wherein Pa50-250 denotes number of protrusions with a height of 50 nm or more and less than 250 nm per 0.1 mm 2 on the surface A and Pb50-250 denotes number of protrusions with a height of 50 nm or more and less than 250 nm per 0.1 mm 2 on the surface B.