Toray Battery Separator Film Co., Ltd.

Tonen Chemical Corporation

Toray Tonen Specialty Separator Godo Kaisha

Tonen Corporation

Tonen Chemical Company

Kawabi & Associates

Toray Industries, Inc.

Kotaro Takita

Shintaro Kikuchi

Koichi Kono

Norimitsu Kaimai

Hidehiko Funaoka

Shigeaki Kobayashi

Kazuhiro Yamada

Sadakatsu Suzuki

Kohtaro Kimishima

Tetsuro Nogata

Soichiro Yamaguchi

Kotaro Kimishima

Kenji Miyasaka

Kenkichi Okamoto

Teiji Nakamura

Yoichi Matsuda

Junko Takita, Legal Representative

Tatsuya Takashima

A method of producing microporous membranes includes stretching a multi-layer layer extrudate having first and second layers, the first layer including a first polyolefin and a first diluent, and the second layer including a second polyolefin and a second diluent, the second polyolefin including polypropylene in an amount of 1.0 wt. % to 40.0 wt. %, the polypropylene having an Mw&#x3e;0.9&#xd7;10and a &#x394;Hm&#x2267;100.0 J/g; removing at least a portion of the diluents to produce a dried membrane having a first length and a first width; stretching the membrane by a first magnification factor of 1.1 to 1.5 and stretching the membrane by a second magnification factor of 1.1 to 1.3; and reducing the width.

Methods of producing and using microporous membranes

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 twin screw extruder for preparing a polymeric solution. The extruder includes an elongated housing having an inlet end, an outlet end, an extruder shaft length L and a pair of interconnecting bores disposed within the housing, a pair of elongated extruder shafts, each having an axis of rotation, the pair of elongated extruder shafts disposed within the pair of interconnecting bores and drivable in at least one direction of rotation, a plurality of extruder screw segments positioned along the pair of elongated extruder shafts in a fixed angular relationship therewith, the plurality of extruder screw segments selected to form multiple extruder stages. The invention also relates to a process for extruding a mixture of polymer and diluent.

Extruder and process for preparing a mixture of polymer and diluent

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.

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

A microporous membrane  comprising (a) from 40 to 60% of a first polyethylene resin having a weight average molecular weight of from 3&#xd7;10to 3.5&#xd7;10and a molecular weight distribution of from 5 to 50, (b) from 20 to 40% of a first polypropylene having a weight average molecular weight of from 0.9&#xd7;10to 1.1&#xd7;10, a molecular weight distribution of from 1 to 50, and a heat of fusion of from to 120 J/g, (c) from 10 to 25% of a second polypropylene having a weight average molecular weight of from 5.7 to 10to 6.6&#xd7;10, a molecular weight distribution of from 5 to 50, and a heat of fusion of from 80 to 120 J/g, and (d) from 0 to 10% of a second polyethylene resin having a weight average molecular weight of from 1&#xd7;10to 3&#xd7;10and a molecular weight distribution of from 5 to 50, percentages based on the mass of the membrane.

Growing community of inventors

Nasushiobara, Japan

Kotaro Takita