US 11,728,100 B2
Polyolefin porous film, separator for energy storage device, and energy storage device
Takanobu Mimura, Sakai (JP); and Ryou Sakimoto, Sakai (JP)
Assigned to UBE CORPORATION, Ube (JP)
Filed by UBE CORPORATION, Ube (JP)
Filed on Mar. 27, 2020, as Appl. No. 16/831,906.
Claims priority of application No. 2019-068600 (JP), filed on Mar. 29, 2019.
Prior Publication US 2020/0313136 A1, Oct. 1, 2020
Int. Cl. H01M 50/417 (2021.01); H01G 11/52 (2013.01); H01M 10/0525 (2010.01); H01M 50/449 (2021.01); H01M 50/489 (2021.01); H01M 50/411 (2021.01)
CPC H01G 11/52 (2013.01) [H01M 10/0525 (2013.01); H01M 50/411 (2021.01); H01M 50/417 (2021.01); H01M 50/449 (2021.01); H01M 50/489 (2021.01)] 7 Claims
 
1. A polyolefin porous film, comprising a polyethylene-based resin and a polypropylene-based resin,
the polyolefin porous film has a pair of polypropylene-based resin layers comprising the polypropylene-based resin on both surfaces of a polyethylene-based resin layer comprising the polyethylene-based resin,
the polyolefin porous film has a film thickness of 8 to 40 μm,
a Gurley value of the polyolefin porous film is 65 to 230 seconds/100cc,
a ratio of the Gurley value of the polyethylene-based resin layer to the Gurley value of the polyolefin porous film is 20% or less,
wherein a weight average molecular weight of the polyethylene-based resin is 450,000 or less,
a molecular weight distribution of the polyethylene-based resin is 6 to 13,
a content of a high molecular weight component having a molecular weight of 1,000,000 or more in the polyethylene-based resin is in a range of 5 to 11% by mass,
a melt flow rate of the polyethylene-based resin is in a range of 0.1 to 10 g/10 minutes, and
a weight average molecular weight of the polypropylene-based resin is 500,000 to 1,000,000.