Process for producing microporous polyolefin film and microporous polyolefin film

Active Publication Date: 2008-03-26
TORAY IND INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the microporous membrane obtained by this production method cannot be said to have sufficient compression resistance.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0076] To by Mw is 2.0×10 6 UHMWPE (Mw / Mn=8) 20% by mass, Mw is 3.5×10 580% by mass of HDPE (Mw / Mn=13.5), Mw / Mn=16 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 obtain a PE composition. 30 parts by mass of the obtained PE composition was charged into a twin-screw extruder (inner diameter 58mm, L / D=42, strong mixing type), and 70 parts by mass of liquid paraffin was 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 make it into a sheet with a thickness of 1.1 mm. gelatinous form. The obtained gel-like molded product was simultaneously biaxially stretched 5×5 times at a temperature of 114° C. using a tenter stretch...

Embodiment 2

[0078] In addition to holding the secondary stretched film on the tenter, a combination of heat setting and thermal relaxation was performed at 124°C to shrink the length in the TD direction to 110% of that before secondary stretching. , except that the heat setting treatment was performed at 124° C. for 30 seconds, a PE microporous membrane was produced in the same manner as in Example 1.

Embodiment 3

[0080] A PE microporous membrane was produced in the same manner as in Example 1 except that the secondary stretching ratio was set to 1.2 times and the temperature of the heat setting treatment was set to 124°C.

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PUM

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Abstract

A microporous polyolefin membrane having excellent compression resistance is obtained by stretching a gel molding comprising a polyolefin and a membrane-forming solvent, removing the membrane-forming solvent, and stretching the resultant membrane again at least uniaxially at a speed of 3% / second or more at a temperature equal to or lower than the crystal dispersion temperature +20°C.

Description

technical field [0001] The present invention relates to a method for producing a polyolefin microporous membrane excellent in compression resistance and useful as a battery separator, and to the microporous membrane. 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. Therefore, excellent permeability, mechanical properties, heat shrinkage resistance, shutdown properties, melting properties, and the like are required. [0003] As a method of improving the physical properti...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J9/00B29C55/02H01M50/403H01M50/406H01M50/417H01M50/426H01M50/491H01M50/494
CPCB29K2023/06B01D67/0027C08J2323/06H01M10/4235B01D71/26H01M2/1653H01M10/052Y02E60/12C08J5/18B29K2023/0641B01D2325/24B29K2105/04B01D69/02B01D2325/20C08J2323/02B01D2323/08B29C55/005H01M2/145Y02E60/10H01M50/403H01M50/417H01M50/406H01M50/491H01M50/494H01M50/426B29C55/02C08J5/22
Inventor 泷田耕太郎山田一博开米教充中村悌二河野公一
Owner TORAY IND INC
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