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Method of manufacturing a microporous polyethylene film

A technology of polyethylene film and manufacturing method, applied in the direction of final product manufacturing, sustainable manufacturing/processing, flat products, etc., can solve problems such as damage to film quality, and achieve the effect of excellent balance of air permeability

Inactive Publication Date: 2014-03-26
TORAY IND INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

If the former is used, when there is foreign matter attached to the surface of the roll or the film, it is easy to cause the problem of damaging the film quality due to surface defects such as pinholes.

Method used

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  • Method of manufacturing a microporous polyethylene film

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1）

[0090] (1) Preparation of a mixture of polymer and solvent for film formation

[0091] The mixture of polymer and film-making solvent is prepared by mixing liquid paraffin with a blend of polyethylene 1 (PE1), polyethylene 2 (PE2). The polymer blend used (a) has a Mw of 3.0 x 10 5 , MWD is 4.05, the amount of unsaturated end groups is 0.14 / 1.0×10 4 Carbon atoms, 95% by mass of PE1 with a melting point Tm of 136.0°C, (b) Mw of 2.0×10 6 , PE2 5% by mass having a melting point of 136.0°C. Here, mass % is based on the weight of the polymers mixed.

[0092] (2) Manufacture of membrane

[0093] A mixture of polymer and film-forming solvent is fed into an extruder and extruded from a sheet-forming die into a sheet-like extrudate. The mold temperature was 210°C. The extrudate was cooled with chill rolls at 20°C. After the cooled extrudate was stretched to 1.4 times at 115°C, it was simultaneously biaxially stretched at 117°C at a stretching ratio of 5 times in both TD and MD wi...

Embodiment 1

[0095] In Example 1, after stretching to 1.8 times at 120°C, simultaneous biaxial stretching was performed with a tenter at a stretching ratio of 5 times in both TD and MD at 123°C. 1 A microporous polyethylene film was obtained in the same manner. Table 1 shows film formation conditions and measurement results.

Embodiment 3）

[0097] After removing the liquid paraffin, a microporous polyethylene film was obtained in the same manner as in Example 1 except that stretching was not performed. Table 1 shows film formation conditions and measurement results.

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Abstract

This method of manufacturing a microporous polyethylene film involves mixing polyethylene and a film-forming solvent, stretching the sheet formed by extrusion from a die, and removing said film-forming solvent. Said stretching involves a step for stretching in the longitudinal direction with a stretch ratio of 1.1-2.0, and a step for stretching in the longitudinal direction and the width direction simultaneously with an surface area magnification ratio of 4-50. Provided is a method of manufacturing a microporous polyethylene film which, when made into a battery, has uniform properties in the winding direction and excellent balance between longitudinal stiffness, air permeability and thermal shrinkage.

Description

technical field [0001] The present invention relates to a method for producing a microporous membrane widely used as a separation membrane used for separation of substances, selective permeation, etc., and as an electrochemical reaction device for alkali metals, lithium secondary batteries, fuel cells, capacitors, etc. spacer material etc. In particular, it relates to a method for producing a polyolefin microporous membrane suitable for use as a separator for lithium ion batteries. Background technique [0002] Polyolefin microporous membranes are widely used as separation membranes, diaphragms, and the like used in separation and selective filtration of various substances. For example, polyolefin microporous membranes are used as microfiltration membranes, separators for fuel cells, separators for capacitors, and the like. Among them, the polyolefin microporous film is particularly suitable as a separator for lithium ion batteries widely used in notebook computers, mobile...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J9/28B29C47/14C08J9/00B29K23/00B29K105/04B29L7/00H01G9/02H01M2/16B29C48/305H01M50/403H01M50/406H01M50/417H01M50/491H01M50/494
CPCY02E60/12H01M10/0525B29K2105/041B29C47/8845C08J2323/02B29C47/0021H01M2/145Y02E60/13B29C47/0057H01G11/52H01M8/1023H01M8/0269H01M2/1653C08J5/2218B29C48/08B29C48/0018B29C48/91B29C48/914Y02P70/50Y02E60/50Y02E60/10H01M50/403H01M50/417H01M50/491H01M50/406H01M50/494C08J9/28H01G9/02B29K2023/00B29K2105/04B29L2007/00H01M50/411
Inventor 伊藤达也河野公一
Owner TORAY IND INC
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