Oriented beta-polypropylene base membrane, polypropylene microporous membrane and method for manufacturing same

A technology of polypropylene microporous film and polypropylene base film, which is applied in the field of microporous film, can solve the problems of poor micropore distribution uniformity, difficult industrial production, and insufficient relative content of β crystals, etc., and achieve uniform deformation mode and high orientation degree , the effect of narrow pore size distribution

Active Publication Date: 2015-11-25
CHENGDU WISEDONE TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the uniformity of the pore size distribution of the polypropylene microporous membrane has been improved, the relative content of β-crystal in the base film is not high enough, and the farther the distance from the polypropylene fiber is, the lower the degree of orientation of the β-crystal is. The uniformity of micropore distribution in the porous film is still poor; at the same time, because this method needs to introduce polypropylene fibers to induce crystallization in the state of the melt standing still, it is difficult to achieve continuous industrial production

Method used

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  • Oriented beta-polypropylene base membrane, polypropylene microporous membrane and method for manufacturing same
  • Oriented beta-polypropylene base membrane, polypropylene microporous membrane and method for manufacturing same
  • Oriented beta-polypropylene base membrane, polypropylene microporous membrane and method for manufacturing same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] In this example, an oriented β-polypropylene base film was prepared, and a polypropylene microporous film was further prepared from the base film, and the steps were as follows:

[0032](1) After mixing raw material polypropylene and β crystal form nucleating agent calcium pimelate, a mixture is formed, and the content of calcium pimelate in the mixture is 0.1wt%, and the mixture is added to a twin-screw extruder Medium-melt plasticization, the temperature of the five sections of the twin-screw extruder from the hopper to the die is set to 160°C, 200°C, 240°C, 240°C, and 230°C, and the melt obtained by melting and plasticizing is set at a screw speed of 30rpm Extrude through an annular die with a diameter of 1.5mm to form a tube blank, and at the same time supply air to the annular die to inflate the tube blank to form a film tube. The film tube is cooled and flattened to obtain an oriented β-polypropylene base film.

[0033] (2) The oriented β-polypropylene base film ...

Embodiment 2

[0037] In this example, an oriented β-polypropylene base film was prepared, and a polypropylene microporous film was further prepared from the base film, and the steps were as follows:

[0038] (1) After mixing raw material polypropylene and β crystal form nucleating agent calcium pimelate, a mixture is formed, and the content of calcium pimelate in the mixture is 0.2wt%, and the mixture is added to a twin-screw extruder Medium-melt plasticization, the temperature of the five sections of the twin-screw extruder from the hopper to the die is set to 160°C, 200°C, 240°C, 240°C, and 230°C, and the melt obtained by melting and plasticizing is set at a screw speed of 30rpm Extrude through an annular die with a diameter of 1.5mm to form a tube blank, and at the same time supply air to the annular die to inflate the tube blank to form a film tube. The film tube is cooled and flattened to obtain an oriented β-polypropylene base film.

[0039] (2) The oriented β-polypropylene base film...

Embodiment 3

[0043] In this example, an oriented β-polypropylene base film was prepared, and a polypropylene microporous film was further prepared from the base film, and the steps were as follows:

[0044] (1) raw material polypropylene is mixed with beta crystal form nucleating agent calcium suberate to form compound, the content of calcium suberate in this compound is 0.3wt%, described compound is added twin-screw extruder Medium-melt plasticization, the temperature of the five sections of the twin-screw extruder from the hopper to the die is set to 160°C, 200°C, 240°C, 240°C, and 230°C, and the melt obtained by melting and plasticizing is set at a screw speed of 30rpm Extrude through an annular die with a diameter of 1.5mm to form a tube blank, and at the same time supply air to the annular die to inflate the tube blank to form a film tube, control the inflation ratio to 6, and the height of the condensation line to be 5cm, and then pass through the chill roll. The film tube is cooled ...

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Abstract

The invention belongs to the field of microporous membranes, and provides an oriented beta-polypropylene base membrane, a polypropylene microporous membrane and a method for manufacturing the same. The oriented beta-polypropylene base membrane comprises polypropylene and beta-crystal nucleating agents. Plate beta-crystals are distributed on membrane substrates and are oriented along directions perpendicular to an extrusion direction of the base membrane, F values of orientation degrees are 0.5-0.8, K values of relative contents of the plate beta-crystals in the base membrane are 0.7-0.95, the thickness of the base membrane is 30-50 micrometers, and the base membrane is manufactured in a blow molding membrane forming mode. The base membrane is subjected to longitudinal-transverse step-by-step bidirectional stretching and heat setting to obtain the polyethylene microporous membrane. The thickness of the microporous membrane is 8-15 micrometers, the average aperture of the microporous membrane is 20-60nm, and the porosity of the microporous membrane is 40%-50%. The oriented beta-polypropylene base membrane, the polypropylene microporous membrane and the method have the advantages that micropores are uniformly formed in the microporous membrane, the microporous membrane is narrow in aperture distribution range and is applicable to products such as lithium ion batteries and power batteries, accordingly, the uniformity of medium transmission density of battery products can be improved, and the thicknesses of the battery products can be reduced.

Description

technical field [0001] The invention belongs to the field of microporous membranes, in particular to an orientation beta-polypropylene base membrane, a polypropylene microporous membrane and a preparation method thereof. Background technique [0002] Microporous membrane is a plastic film with numerous interpenetrating micropores, and its pore size is between 0.01 and 10 μm. It is widely used in sewage treatment, gas separation and battery diaphragm and other fields. Polypropylene is currently one of the main materials for preparing polymer microporous membranes due to its high mechanical properties, good chemical corrosion resistance and low production cost. In the prior art, the polypropylene microporous membrane is mainly prepared by double-stretching in a dry method. This method needs to prepare a β-polypropylene base film first, and the polypropylene microporous membrane can be obtained after the base film is unidirectionally or biaxially stretched. [0003] At present...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08L23/12C08K5/098C08K5/3437C08K5/20C08J5/18B29C55/28
CPCB29C55/28C08J5/18C08J2323/12C08K5/098C08K5/20C08K5/3437C08L2203/16C08L2205/242C08L23/12
Inventor 吴桐
Owner CHENGDU WISEDONE TECH
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