Toray Battery Separator Film Co., Ltd.

Toray Tonen Specialty Separator Godo Kaisha

Toray Industries, Inc.

Tonen Chemical Corporation

Shintaro Kikuchi

Kotaro Takita

Kazuhiro Yamada

Koichi Kono

Hideto Mitsuoka

Toshiya Saito

Kotaro Kimishima

Junko Takita, Legal Representative

Teiji Nakamura

A biaxially stretched microporous film includes band-like polyethylene material having a film width of not less than 300 mm wherein distribution of physical properties in the film width direction and the thickness variation is less than 1.00 &#x3bc;m and air permeability variation is not greater than 50 seconds/100 mL. The polyethylene microporous film has excellent planarity and uniformity of physical properties required when used in a large-area configuration as a separator film of a lithium ion battery for automobiles or consumer electronics.

Biaxially stretched microporous film

A polyolefin multilayer microporous membrane includes at least first microporous layers which form both surface layers of the membrane and at least a second microporous layer disposed between the both surface layers, wherein static friction coefficient of one of the surface layers of the polyolefin multilayer microporous membrane against another surface layer in a longitudinal direction (MD) is 1.1 or less, and wherein pore density calculated from an average pore radius measured by mercury porosimetry method and porosity, according to Formula (1) is 4 or more:Pore density=()&#xd7;10&#x2003;&#x2003;(1)wherein A represents the average pore radius (nm) measured by mercury porosimetry method and P represents the porosity (%).

Multilayered microporous polyolefin film

A polyethylene microporous membrane has a Gurley air permeability of 1 to 1,000 sec/100 mL/25 &#x3bc;m, wherein the total length of waviness widths in the width direction of the polyethylene microporous membrane is not more than one-third of the overall width of the microporous membrane. The polyethylene microporous membrane has excellent planarity without compromising any other important physical property such as permeability.

Polyethylene microporous membrane and process for manufacturing same

A multi-layer, microporous polyolefin membrane comprising a polypropylene layer and a polyethylene resin layer and having well-balanced permeability, mechanical strength, heat shrinkage resistance, shutdown properties and meltdown properties can be obtained by (1) forming a sheet comprising a gel-like polypropylene layer containing a membrane-forming solvent or a polypropylene layer containing no membrane-forming solvent and a gel-like polyethylene resin layer containing a membrane-forming solvent, stretching the sheet at two-stage temperatures, and then removing the membrane-forming solvent, or (2) forming a gel-like polypropylene sheet containing a membrane-forming solvent or a polypropylene sheet containing no membrane-forming solvent, and a gel-like polyethylene resin sheet containing a membrane-forming solvent, stretching them at two-stage temperatures, removing the membrane-forming solvent, and then laminating the resultant microporous polypropylene membrane and the resultant microporous polyethylene membrane.

Method for producing multi-layer, microporous polyolefin membrane

A multi-layer, microporous polyolefin membrane having at least three layers, which comprises first microporous layers made of a polyethylene resin for constituting at least both surface layers, and at least one second microporous layer comprising a polyethylene resin and polypropylene and disposed between both surface layers, the heat of fusion (&#x394;H) of the polypropylene measured by differential scanning calorimetry being 90 J/g or more, and the polypropylene content in the second microporous layer being 50% or less by mass based on 100% by mass of the total of the polyethylene resin and the polypropylene.

Multi-layer microporous polyolefin membrane and battery separator

A multi-layer, microporous polyolefin membrane comprising first microporous layers constituting at least both surface layers, and at least one second microporous layer disposed between both surface layers, the first microporous layer comprising a first polyethylene resin containing 8% or more by mass of ultra-high-molecular-weight polyethylene having a weight-average molecular weight of 1&#xd7;10or more, the second microporous layer comprising a second polyethylene resin containing 7% or less by mass of the ultra-high-molecular-weight polyethylene, and having a structure in which a pore diameter distribution curve obtained by mercury intrusion porosimetry has at least two peaks, and the total thickness of the first microporous layers being 15-60% per 100% of the total thickness of the first and second microporous layers.

Multi-layer, microporous polyolefin membrane, its production method, battery separator, and battery

The invention relates to microporous polymeric membranes suitable for use as battery separator film. The invention also relates to a method for producing such a membrane, batteries containing such membranes as battery separators, methods for making such batteries, and methods for using such batteries.

Microporous membranes and methods for producing and using such membranes

(1) a combination of a microporous layer made of a polyethylene resin and a microporous layer made of polypropylene and a heat-resistant resin having a melting point or a glass transition temperature of 170&#xb0; C. or higher, or (2) a combination of a microporous layer made of a polyethylene resin and a microporous layer made of polypropylene and inorganic filler having an aspect ratio of 2 or more provides a multi-layer, microporous polyolefin membrane with well-balanced permeability, mechanical strength, heat shrinkage resistance, shutdown properties and meltdown properties.

Multi-layer, microporous polyolefin membrane, its production method, and battery separator

The invention relates to a polyolefin composition. The polyolefin composition can be in the form of a multi-layer, microporous polyolefin membrane comprising a first microporous layer containing 7% or less by mass of ultra-high-molecular-weight polyethylene having a weight-average molecular weight of 1&#xd7;10or more, and having a structure in which a pore size distribution curve obtained by mercury intrusion porosimetry has at least two peaks, and a second microporous layer containing 8% or more by mass of the ultra-high-molecular-weight polyethylene.

Polyolefin composition, its production method, and a battery separator made therefrom

A microporous polyethylene membrane made of a polyethylene resin having a ratio (mass-average molecular weight/number-average molecular weight) of 5 to 300 and comprising 1% or more by mass of ultra-high-molecular-weight polyethylene having a mass-average molecular weight of 7&#xd7;10or more, the microporous polyethylene membrane comprising (a) a coarse-structure layer having an average pore diameter of more than 0.04 &#x3bc;m, which is formed on at least one surface, and (b) a dense-structure layer having an average pore diameter of 0.04 &#x3bc;m or less, an area ratio of the coarse-structure layer to the dense-structure layer in a membrane cross section being 0.1 to 0.8.

Microporous polyethylene membrane, its production method, and battery separator

A multi-layer, microporous polyethylene membrane comprising (a) a first microporous layer made of a polyethylene resin, and (b) a second microporous layer comprising a polyethylene resin, and a heat-resistant polymer having a melting point or a glass transition temperature of 170&#xb0; C. or higher, the heat-resistant polymer being dispersed in the form of fine particles in the polyethylene resin, and the second microporous layer having pores containing fine particles of the heat-resistant polymer as nuclei from which the cleavage of polyethylene resin fibrils starts, the multi-layer microporous polyethylene membrane having well-balanced shutdown properties, meltdown properties, permeability, mechanical strength, heat shrinkage resistance and compression resistance.

Multi-layer, microporous polyethylene membrane, battery separator formed thereby and battery

The invention relates to a particular multi-layer microporous membrane having a good balance of important properties, including excellent electrochemical stability and low heat shrinkage, while maintaining high permeability and heat resistance, with good mechanical strength, compression resistance and electrolytic solution absorption. Of particular importance when used as a battery separator, the present multi-layer microporous membrane exhibits excellent heat shrinkage, melt down temperature and thermal mechanical properties, i.e. low maximum shrinkage in the molten state. The multi-layer microporous membrane of the present invention is manufactured by layering, such as for example by coextrusion, one or more microporous membrane first layers and one or more microporous membrane second layers, such as on one or both sides of a first layer. The invention further relates to battery separators comprising the multi-layer microporous membrane and batteries utilizing the battery separators.

Multi-layer microporous membrane, battery separator and battery

The invention relates to a microporous membrane which comprises polyethylene, the microporous membrane having a differential pore volume curve with an area under the curve over the range of pore diameters of from about 100 nm to about 1,000 nm that is 25% or more of a total area under the curve over the range of pore diameters of from about 10 nm to about 1,000 nm.

Microporous polymer membrane

A process of producing a membrane includes extruding diluent and polymer to form an extrudate, the polymer includes a first polyethylene having an Mw&#x3c;1.0&#xd7;10, a second polyethylene having an Mw&#x2267;1.0&#xd7;10, and a polypropylene having an Mw&#x2267;5.0&#xd7;10and a &#x394;Hm&#x2267;80.0 J/g; wherein the sum of the polypropylene having an Mw&#x2267;5.0&#xd7;10and a &#x394;Hm&#x2267;80.0 J/g and the second polyethylene is &#x2267;15.0 wt. % and processing the extrudate into a membrane having a thickness &#x2266;12.0 &#x3bc;m by stretching the extrudate in at least one planar direction at about 108.0 to 116.0&#xb0; C. after removing the solvent to a magnification factor of &#x2266;1.1 and excludes any stretching of the extrudate after removing the solvent at a magnification factor or &#x3e;1.1 and removing at least a portion of the diluent from the extrudate.

Methods of producing the membranes and the uses of membranes as battery separator films

The invention relates to polyolefin membranes and membrane precursors comprising polyethylene and polypropylene. The polyolefin membrane can be a microporous polyolefin membrane comprising a first microporous layer and at least one second microporous layers where the first and second layers contain polypropylene and polyethylene, and the amount of polyethylene in the first layer is at least about 80 wt. % and the amount of polyethylene in the second layer is at least about 50 wt. %. The amount of polyethylene is higher in the first microporous layer than in the second microporous layer, and the total amount of the polyethylene in the first and second microporous layers is at least about 61 wt. %, based on the weight of the multi-layer, microporous polyolefin membrane.

Growing community of inventors

Saitama, Japan

Shintaro Kikuchi