Sk Innovation Co., Ltd.

Sk Energy Co., Ltd.

Sk Ie Technology Co., Ltd.

Sk Corporation

In Hwa Jung

Young Keun Lee

Jang Weon Rhee

Byoung Cheon Jo

Jung Moon Sung

Chol Ho Lee

Won Young Cho

Byung Rae Jung

Jang-weon Rhee

Gwi Gwon Kang

Gwig Won Kang

Provided are a polyethylene microporous membrane, a method for manufacturing the same, and a separator including the microporous membrane. According to an embodiment, a polyethylene microporous membrane which has a thickness of 3 μm to 30 μm, a puncture strength of 0.15 N/μm or more, a shrinkage rate in the transverse direction of 5% or less as measured after being allowed to stand at 121° C. for 1 hour, and a PS index represented by the following Equation 1 of 110 or more is provided:PS index=[gas permeability (×10Darcy)×porosity (%)]+[shrinkage rate (%) in the transverse direction at 121° C.].   [Equation 1]

Polyethylene microporous membrane, method for manufacturing the same, and separator including microporous membrane

Provided is a porous multi-layer film having two or more layers that is used as a separator for battery. In the film, more than 2 layers have different porosities and pore sizes. The film has a thickness of 9 to 50 &#x3bc;m, a machine direction (MD) loop stiffness of 0.008 mg/&#x3bc;m or more, puncture strength of 0.15 N/&#x3bc;m or more, permeability of 1.5&#xd7;10Darcy or more, shut-down temperature of 140&#xb0; C. or less, melt-down temperature of 170&#xb0; C. or more, a transverse direction (TD) maximum shrinkage of 25% or less in Thermomechanical Analysis (TMA) under a load of 1 mN/(1 &#x3bc;m&#xd7;6 mm), and melt down temperature of 160&#xb0; C. or more. Since the porous multi-layer film shows excellent thermal stability at high temperature and electrolyte retaining property due to a dual pore structure, the film shows a superior effect when used as a separator for high-capacity/high-power lithium ion battery.

Porous multi-layer film with improved thermal properties

Provided is a method of manufacturing a microporous polyolefin film useable as a battery separator, which is easy to control strength, permeability and shrinking properties of the microporous film and embodies excellent quality uniformity and production stability in fabricating the microporous film.

Method for preparing microporous polyolefin film with improved productivity and easy control of physical properties

A microporous polyolefin multilayer film which is used as a separator for a battery is a 3 layer microporous film which is prepared by a wet process to have both surface layers containing polyethylene of 95 wt % or more having a melting temperature of 125&#xb0; C. or higher, and an inner layer containing polypropylene of 50 to 90 wt % having a melting temperature of 160&#xb0; C. or higher and polyethylene of 10 to 50 wt % having a melting temperature of 125&#xb0; C. or higher. A thickness of the film is 9-50/M, a puncture strength is 0.15N//M or more, a permeability is 1.5&#xd7;10Darcy or more, a multiplication of the puncture strength and the permeability is 0.4&#xd7;10Darcy&#xb7;N/&#x3bc;m or more, a shrinkage in a transverse direction at 120&#xb0; C. for 1 hour is 15% or less, and a melt fracture temperature of 160&#xb0; C. or higher.

Microporous polyolefin multi layer film

Disclosed is a microporous high density polyethylene film for a battery separator and a method of producing the same. The microporous high density polyethylene film includes high density polyethylene with a weight average molecular weight of 2&#xd7;10-5&#xd7;10, containing 5 wt % or less molecule with a molecular weight of 1&#xd7;10or less. The microporous high density polyethylene film has tensile strengths of 1,100 kg/cmor more in transverse and machine directions respectively, a puncture strength of 0.22 N/&#x3bc;m or more, a gas permeability (Darcy's permeability constant) of 1.3&#xd7;10Darcy or more, and shrinkages of 5% or less in machine and transverse directions, respectively. Particularly, the microporous high density polyethylene film has an excellent extrusion-compoundabiliy and stretchability and a high productivity, and can improve the performances and stability of a battery produced using the same.

Method of producing microporous high density polyethylene film

Disclosed is a microporous polyethylene film for a battery separator and a method of producing the same. The microporous polyethylene film comprises a resin mixture, which includes 100 parts by weight of composition containing 20-50 wt % polyethylene with a weight average molecular weight of 5&#xd7;10-3&#xd7;10(component I) and 80-50 wt % diluent (component II), 0.1-2 parts by weight of peroxide (component III), and 0.05-0.5 parts by weight of anti-oxidant (component IV). The microporous polyethylene film has a puncture strength of 0.22 N/&#x3bc;m or more and a gas permeability (Darcy's permeability constant) of 1.3&#xd7;10Darcy or more. The present invention increases production efficiency of the microporous film, and improves performances and stability of the battery when the microporous polyethylene film is used in a battery separator.

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Cheonan-si, South Korea

In Hwa Jung