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Microporous polyolefin film and process for producing the same

A technology of microporous membrane and manufacturing method, applied in chemical instruments and methods, membrane, membrane technology, etc., can solve the problems of deterioration of cycle characteristics, insufficient battery capacity, insufficient compression resistance of microporous membrane, etc. Excellent mechanical strength and compression resistance, large pore diameter, and excellent particle removal performance

Active Publication Date: 2008-04-02
TORAY IND INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the compression resistance of the microporous membranes described in JP-A-6-240036 and WO 2000 / 20492 cannot be said to be sufficient.
When the compression characteristics of the microporous membrane are poor, there is a high possibility that the capacity of the battery will be insufficient (deterioration of the cycle performance) when used as a battery separator

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0081] To by Mw is 2.0×10 6 UHMWPE (Mw / Mn=8) 18% by mass, Mw is 3.0×10 5 HDPE (Mw / Mn=8.6) 82% by mass, Mw / Mn=12.0 PE (melting point: 135°C, crystal dispersion temperature: 100°C), as an antioxidant, add 0.375 parts by mass per 100 parts by mass of PE Tetrakis[methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate]methane to give a PE composition. 32 parts by mass of the obtained PE composition was charged into a twin-screw extruder (inner diameter 58 mm, L / D=42, strong mixing type), and 68 parts by mass of liquid paraffin were supplied from the side feeder of the twin-screw extruder , melt-kneaded under the conditions of 210° C. and 200 rpm, and prepared a PE solution in an extruder. Next, extrude the PE solution from a T-die provided at the head end of the extruder to form a thin sheet with a thickness of 1.4 mm, and form a gelatinous sheet while winding it with a cooling roll whose temperature is adjusted to 40°C. gelatinous form. The obtained gel-like molded product...

Embodiment 2

[0083] The resin concentration in the PE solution is set to 28% by mass, the temperature of the first heat treatment is set to 124°C, the second stretching is carried out at a magnification of 1.2 times along the MD direction, and the temperature of the second heat treatment is set to 131°C, except Except for this, a PE microporous membrane was produced in the same manner as in Example 1.

Embodiment 3

[0085] As shown in Table 1, the Mw used as HDPE is 3.5×10 5 , Mw / Mn is a material of 13.5, the resin concentration in the PE solution is set to 30% by mass, the temperature of the first heat treatment is set to 124°C, the magnification of the second stretch is set to 1.5 times, and the second heat treatment A PE microporous membrane was produced in the same manner as in Example 1 except that the temperature was 128°C.

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PUM

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Abstract

The microporous polyolefin film produced by drawing a gel molding containing a polyolefin and a solvent for film formation in at least a uniaxial direction, performing thermofixing treatment, removing the solvent for film formation and once more drawing the molding in at least a uniaxial direction has large pore diameter and excels in air permeability, mechanical strength and compression resistance.

Description

technical field [0001] The present invention relates to a polyolefin microporous membrane and a method for producing the same, in particular to a polyolefin microporous membrane having a large pore diameter, excellent air permeability, compression resistance, and mechanical strength, and useful as a separator for batteries and various filters and methods of manufacture thereof. Background technique [0002] Polyolefin microporous membranes can be used in various applications such as separators for batteries, separators for electrolytic capacitors, various filters, moisture-permeable waterproof clothing, reverse osmosis filtration membranes, ultrafiltration membranes, and precision filtration membranes. When a polyolefin microporous membrane is used as a separator for a battery, especially a separator for a lithium ion battery, its performance is closely related to battery characteristics, battery productivity, and battery safety. For this reason, excellent permeability, mec...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J9/00B29C55/02
CPCB01D2325/02B01D71/26B29K2023/00B01D2325/24B29K2105/04B01D2325/20B01D69/02B29C55/005C08J5/18C08J2323/02B29K2023/0641B01D67/0027Y10T428/24504Y02E60/10B01D2325/0283C08J5/22C08J9/00C08J9/22C08F10/00
Inventor 泷田耕太郎开米教充中村悌二河野公一
Owner TORAY IND INC
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