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Production of polyolefin microporous membrane

A technology of microporous membrane and production method, which is applied in the direction of chemical instruments and methods, membrane technology, semipermeable membrane separation, etc., can solve the problems of uneven overall thickness, uneven transverse thickness, and poor surface flatness of thick slices, and achieve The effect of smooth appearance, improved flatness and uniform strength

Active Publication Date: 2008-02-13
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

[0005] Japanese patents JP2001-200082, JP2001-81221, etc. disclose the method of direct casting, the overall thickness of the thick sheet can be controlled by the die lip, but the flatness of the surface is poor, especially when the viscosity of the polyolefin solution is small, During the extrusion process, it is easy to form fine longitudinal stripes (slight fluctuations in the transverse thickness of the thick sheet), so that the biaxially stretched film produces longitudinal stripes, that is, the transverse thickness is uneven
The method of Japanese patent JP2002-367590 can improve the smoothness of the surface of the thick sheet, but it is calendered at a large ratio on the calender, which may easily cause the overall thickness of the thick sheet to be uneven

Method used

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  • Production of polyolefin microporous membrane
  • Production of polyolefin microporous membrane
  • Production of polyolefin microporous membrane

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] 24 (% by weight) of high-density polyethylene (weight-average molecular weight 2.7 × 10 5 , melting point), 6 (weight%) UHMWPE (weight average molecular weight 1.0×10 6 , melting point) into the twin-screw extruder (diameter 78mm, L / D=48, strong mixing type), add 70 (weight %) liquid paraffin (kinematic viscosity 90cst / 40 ℃), melt kneading under the conditions of 160 ℃ and 150 rpm to prepare a polyethylene solution.

[0029] 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. The thick sheet was preheated in an infrared preheating box at 120°C for 20 seconds, and then entered into a three-roll calender for calendering. The temperature of the pressing rolls was 100°C, and the thickness reduction ratio was 5%.

[0030] Stepwise biaxially stretch the thick sheet after calendering, a...

Embodiment 2

[0032] During the calendering process of the three-roll calender, the thickness reduction ratio of the slab was 8%, and the other steps were the same as in Example 1. The thickness uniformity of the polyolefin microporous membrane in this example is shown in Figure 2.

Embodiment 3

[0034] During the calendering process of the three-roll calender, the temperature of the press rolls was 110° C., and the other steps were the same as in Example 1. The thickness uniformity of the polyolefin microporous membrane in this example is shown in Fig. 3 .

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Abstract

A process for preparing the millipore polyolefin membrane includes such steps as fusing polyolefin resin, mixing it with solvent, extruding out, cooling to become thick sheet, preheating, calendaring, bi-directional stretching to obtain film, eluting out solvent and heat treating.

Description

technical field [0001] The invention relates to a production method of a polyolefin microporous membrane, in particular to a production method of a polyolefin microporous membrane capable of effectively improving the thickness uniformity of the polyolefin microporous membrane. 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 mix polyolefin and solvent to form a homogeneous solution. The solution is extruded through the die head of the extruder, and cooled on the casting roll to form a thick sheet, and the thick sheet is biaxially stretched into...

Claims

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Application Information

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IPC IPC(8): B01D71/26
Inventor 罗明俊尤臻刘会权张伟何一凡彭海生
Owner 康辉南通新材料科技有限公司