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Method for making polyolefin microporous membrane

A technology of microporous film and production method, which is applied to flat products, applications, household appliances, etc., can solve the problems of deterioration of air permeability of polyolefin microporous film, achieve the effects of reducing shrinkage, improving air permeability, and excellent air permeability

Active Publication Date: 2010-06-16
康辉南通新材料科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Japanese patents JP 2003-192822, JP2002-284918, etc. directly carry out the subsequent washing and drying process after biaxially stretching the film, and the film will undergo relatively large shrinkage during the drying process after washing, making the final polyolefin microporous The air permeability of the membrane deteriorates

Method used

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  • Method for making polyolefin microporous membrane

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] 24 (% by weight) of high-density polyethylene (weight-average molecular weight 2.7 × 10 5 , melting point 133 ° C), 6 (weight%) UHMWPE (ultra-high molecular weight polyethylene, weight average molecular weight 1.0 × 10 6 , fusing point 138 ℃) drop into twin-screw extruder (diameter 78mm, L / D=48, strong mixing type), add the liquid paraffin (kinematic viscosity 90cst) of 70 (weight %) by side feeding port with metering pump / 40°C), melted and kneaded under the conditions of 200°C and 150 rpm to prepare a polyethylene solution.

[0023] Pass the polyethylene solution through a T-shaped die (die lip opening 1.2 mm, width 260 mm), extrude at a speed of 3 m / min, and cool the cast sheet on a casting roll with a surface temperature of 10 ° C to obtain a 1.0 mm thick Thick slices.

[0024] The thick sheet is subjected to step-by-step biaxial stretching first longitudinally and then transversely, and the stretching ratio is longitudinal × transverse = 5 × 5 times, wherein the ...

Embodiment 2

[0028] During the first heat treatment, the treatment temperature was 120° C., and the other steps were the same as in Example 1.

Embodiment 3

[0030] During the heat treatment for the first time, the treatment time was 5 seconds, and the other steps were the same as in Example 1.

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Abstract

This invention relates to a manufacturing method for polyolefin micro-porous films including the following steps: a, melting the polyolefin resin and a solvent to a uniform solution, b, extruding outthe solution by a mold head of an extrusion machine to be cooled and cast to a thick plate on a roller, c, stretching the plate in dual way and making it to a thin film, e, washing off the solvent from the film to be dried, f, heating it again to get a polyolefin micro-porous film characterizing in carrying out a first heat process to the film stretched in two way under 80-150deg.C for 1-50 secondto form step d.

Description

technical field [0001] The invention relates to a method for making a polyolefin microporous membrane, in particular to a method for making a polyolefin microporous membrane with excellent air permeability and equipped with a secondary heat treatment process. Background technique [0002] Polyolefin microporous membrane is a film-like material containing micropores. It is widely used in the production of non-aqueous electrolyte battery separators, capacitor separators, various separation membranes, and water treatment membranes. [0003] The production methods of polyolefin microporous membranes include solvent method, stretching and opening method, etc., and solvent method is generally used. The known solvent method is to heat, melt and knead polyolefin and solvent to form a homogeneous solution. The solution is extruded through the die of the extruder, and cooled on the casting roll to form a thick sheet. The thick sheet is biaxially stretched into a The film, the solvent...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B29D7/01B29C71/02B29C55/12B29K23/00
Inventor 罗明俊尤臻刘会权何一帆张伟廖凯明
Owner 康辉南通新材料科技有限公司