Polyolefin microporous membrane as well as preparation method and application thereof

Abstract

The invention discloses a preparation method of a polyolefin microporous membrane, the polyolefin microporous membrane prepared by using the preparation method and an application of the polyolefin microporous membrane. According to the preparation method, a polyolefin melt can be rapidly subjected to draft cooling to form a base membrane at a speed of 10-200m / min by adopting a matte chilling roller which has the surface roughness (Ra value) of 0.04-2mu m, the diameter of 200-2000mm and the temperature of 10-100 DEG C, wherein the distance between the melt and the roller surface is 2-200mm. The melt cooling and freezing speed is accelerated by using the matte chilling roller, the influence of air in the casting and cooling process is effectively reduced and wavy patterns are reduced. The polyolefin microporous membrane prepared by adopting the preparation method has better uniformity and can be widely applied to the fields of battery diaphragms, filtering membranes, medicinal membranes or the like.

Description

technical field [0001] The present application relates to the field of polyolefin materials, in particular to a method for preparing a polyolefin microporous membrane, a polyolefin microporous membrane prepared by the method, and applications of the polyolefin microporous membrane. Background technique [0002] Polyolefin microporous membranes are widely used in battery separators, filtration membranes, medical membranes and other fields. Preparation of microporous membranes with good uniformity is a difficult point in the production process. Especially when these microporous membranes are used as battery separators, the importance of uniformity is even more prominent. On the one hand, the uniformity of the battery separator affects the consistency between each battery cell, and on the other hand, it also affects the consistency of charge and discharge between the positive and negative electrodes inside each battery. These will adversely affect the pass rate, safety and li...

AI Technical Summary

Problems solved by technology

During the cooling process of the melt close to the casting roll, the high-speed movement of the casting roll will form an air layer between the melt and the roll, and the fluctuation of the air will cause the melt to cool unevenly and produce waves, which will seriously affect the uniformity of the product. quality and application

At present, in order to avoid the above problems, researchers mainly use positive pressure air knives, negative pressure air knives and edge-holding devices to assist the melt roll, but this auxiliary method cannot completely solve the problem of the diaphragm caused by this fluctuation. Uniformity

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