Mitsubishi Plastics, Inc.

Toru Terakawa

Takeyoshi Yamada

Yasushi Usami

Miho Yamamoto

This polyolefin resin porous film can be easily produced, and when used as a non-aqueous electrolyte cell separator, can suppress clogging and can evince a high cell output. The polyolefin resin porous film is a porous film having a polyolefin resin as the primary component and is characterized by the average flow diameter pressure (P) being 1500-2500 kPa, the bubble point pressure (P) being 300-1500 kPa, and the ratio (Pa/P) of the air permeability (Pa) and the bubble point pressure (P) being no greater than 0.35 sec/(100 ml&#xb7;kPa).

Polyolefin resin porous film, and non-aqueous electrolyte cell separator using same

Provided is a porous polypropylene film having both air permeability properties and puncture strength. A porous polypropylene film which has an air permeability of 700 seconds/100 ml or less and a puncture strength of 1.5 N or greater, and has &#x3b2; activity can be obtained when the porous polypropylene film is made to have a tensile strength in the machine direction of the film, E, of 100 MPa or greater, a tensile strength in the transverse direction to the machine direction, E, of less than 100 MPa, and a ratio of Eand E, E/E, of 1.5 to 10.

Porous polypropylene film

Provided is a laminated porous film having excellent shutdown characteristics and breakdown characteristics, good tearing strength and dimensional stability, and B activity. The laminated porous film comprises layer A, the main component of which is a polypropylene resin, and layer B which contains a polyethylene resin, and the ratio of the rearing strength (H) in the machine direction (MD) of the laminated porous film and the tearing strength (H) in the transverse direction (TD) of the laminated porous film with respect to the machine direction (H) (H) is 0.08 to 2.0.

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Nagahama, Japan

Toru Terakawa