Microporous membrane, method for producing same, and battery separator using same

A technology of a microporous membrane and a manufacturing method, which is applied in battery pack components, power system fuel cells, circuits, etc., can solve problems such as membrane characteristics decline and molecular weight reduction, and achieve the effects of low shutdown temperature and high safety.

Active Publication Date: 2013-09-25
TORAY IND INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

On the other hand, the harsh mixing conditions are caused by the reduction of molecular weight due to molecular chain scission, which degrades the membrane properties.

Method used

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  • Microporous membrane, method for producing same, and battery separator using same
  • Microporous membrane, method for producing same, and battery separator using same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0143] (1) Preparation of a mixture of polymer and film-making solvent

[0144] The mixture of polymer and film-making solvent was prepared by mixing liquid paraffin with a blend of PMP1, PP1, PE1, PE2. The polymer blend uses: (a) 20wt% polymethylpentene PMP1 (Mitsui Chemicals TPX MX002) (its MFR is 21dg / min, melting point Tm is 222°C); (b) 20wt% Mw is 1.1 ×10 6 , MWD is 8.0, ΔHm is the polypropylene (PP1) of 114J / g; (c) 30wt% Mw is 5.6×10 5 , MWD is 4.05, the amount of unsaturated end groups is 0.14 / 1.0×10 4 Carbon atom, melting point Tm is polyethylene (PE1) of 136.0 ℃; (d) Mw of 30.0wt% is 1.9×10 6 , Polyethylene (PE2) with a melting point of 136.0°C. Here, wt% is based on the weight of the mixed polymer.

[0145] (2) Manufacture of film

[0146] The mixture of polymer and film-forming solvent is fed into the extruder and extruded as a sheet-like extrudate from a sheet-forming die. The mold temperature was 210°C. The extrudate was cooled with chill rolls at 20°C. T...

Embodiment 2～5、 comparative example 1

[0148] Except for the items described in Table 1, a microporous membrane was produced in the same manner as in Example 1. The raw materials and process conditions are as described in Table 1.

[0149] [Table 1]

[0150] 【Table 1】

[0151]

Embodiment 6、7 and comparative example 2、3

[0153]A microporous membrane was produced in the same manner as in Example 1 except for those described in Table 2. In addition, in the comparative example, as described in Table 2, the following PMP was used.

[0154] (a) PMP2 (Mitsui Chemicals TPX DX820, MFR=180dg / min, Tm=236°C), PMP3 (Mitsui Chemicals TPX DX310, MFR=100dg / min, Tm=223°C)

[0155] [Table 2]

[0156] 【Table 2】

[0157]

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Abstract

The present invention is a microporous membrane which contains (a) a polymethyl pentene, (b) a polyethylene and (c) a polypropylene and which has a meltdown temperature of 180 DEG C or more, a TD thermal shrinkage at 170 DEG C of 35% or less, and a thickness variation rate per membrane thickness of 10% or less. The purpose of the present invention is to provide a microporous membrane that has high meltdown temperature, low shutdown temperature and resistance to thermal shrinkage at high temperatures, which have not been achieved by conventional technology.

Description

technical field [0001] The present invention relates to a microporous membrane that has a high melt down temperature and is resistant to thermal shrinkage at high temperatures. The film thickness change rate (film thickness standard deviation) per unit film thickness of the microporous film of the present invention is 10% or less, obtained by the following method: within the range of mixing energy of 0.1 to 0.65KWh / kg, the mixture containing A mixture of polymethylpentene (a), polyethylene (b), and polypropylene (c) film-forming solvent and polymer is melt-extruded, the extruded mixture is stretched, and the film-forming solvent is removed, thereby production. The microporous membrane can be used as a battery separator and the like, and is particularly preferably used for a lithium ion battery. Background technique [0002] Microporous membranes are known to be useful as battery separators (hereinafter referred to as BSF) for primary and secondary batteries. Examples of t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J9/28H01M2/16H01M50/403H01M50/406H01M50/417H01M50/489H01M50/491
CPCH01M2250/20C08L23/10C08J5/18C08J2423/04C08J2423/10C08J2423/20Y02T90/40Y02E60/50Y02E60/10H01M50/403H01M50/417H01M50/406H01M50/491H01M50/489H01G11/52C08L23/04C08L23/20C08J9/28C08L23/00H01M50/411
Inventor 石原毅河野公一
Owner TORAY IND INC
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