Sk Innovation Co., Ltd.

In-Hwa Jung

Young-Keun Lee

Jang-weon Rhee

Je-An Lee

Gwi-Gwon Kang

Byoung-Cheon Jo

Jung-Moon Sung

Chol-Ho Lee

Disclosed in the present invention are a microporous polyethylene film and a method of manufacture thereof. The polyethylene microporous film manufactured according to the present invention may contribute to an increased productivity of stable products as its extrusion and stretching may be done readily. And thus manufactured product may be used for battery separators and various filters owing to its high gas permeability, superior puncture strength, and small ratio of shrinkage.

Microporous polyethylene film manufactured according to liquid-liquid phase separation and method of producing the same

The present invention is related to microporous polyolefin films that may be used for battery separators and the methods of manufacturing the same. These microporous polyolefin films are characterized by being manufactured in a method comprising the steps of melt-extruding a composition, comprised of 20-50 weight % of a resin composition, comprised of 90-98 weight % of polyethylene (Component I) having a weight average molecular weight of 2&#xd7;10&#x2dc;4&#xd7;10and less than 5 weight % of molecules of which molecular weight is less than 1&#xd7;10and less than 5 weight % of molecules of which molecular weight is greater than 1&#xd7;10, and 2-10 weight % of polypropylene (Component II) of which weight average molecular weight is 3.0&#xd7;10&#x2dc;8.0&#xd7;10and the peak of the melting point is higher than 145&#xb0; C., and 80-50 weight % of a diluent (Component III), to mold in the form of sheets; stretching the above sheets to the form of films; extracting the diluent from the above films; and heat-setting the above films. They are also characterized by having a puncture strength of greater than 0.14 N/&#x3bc;m, Darcy's permeability constant of greater than 1.5&#xd7;10Darcy, shut-down temperature of microporous films of lower than 140&#xb0; C., and melt-down temperature of higher than 160&#xb0; C. They can enhance the performance and stability of batteries using them as well as the productivity of microporous films owing to their high thermal stability and superior extrusion compoundability and physical properties.

Microporous polyolefin film with improved meltdown property and preparing method thereof

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Cheonan, South Korea

In-Hwa Jung