Composite polypropylene microporous membrane, and preparation method and application thereof

A technology of compounding polypropylene and microporous film, applied in the field of microporous film, can solve the problems of poor fit, poor wettability, low surface energy and so on

Inactive Publication Date: 2019-03-05
BEIJING NORMAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When the diaphragm prepared by the method is used as a lithium-ion battery diaphragm, since polypropylene is a non-polar material with low surface energy, the infiltration of the non-polar polypropylene diaphragm by the carbonate polar electrolyte in the battery poor sex
At the same time, during the battery assembly process, the non-polar polypropylene separator and the battery pole piece are also prone to poor bonding due to polarity differences

Method used

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  • Composite polypropylene microporous membrane, and preparation method and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0124] The homopolypropylene resin whose melt index is 2.5g / 10min is mixed with the polypropylene beta crystal nucleating agent N,N-dicyclohexyl-2,6 naphthalene diamide accounting for 0.03wt% of the homopolypropylene resin, and passed The feeder 1 is fed into the single-screw extruder 2. After melting at a temperature of 160-230°C, it is metered by the metering pump 3. After passing through the filter 4, it enters the T-shaped die head 6 through the second melt pipeline 5. out, and cooled on the casting roll 7 to obtain a polypropylene film containing a β-crystal nucleating agent. The thickness of the polypropylene membrane containing β-crystal nucleating agent is 140 microns.

[0125] The film passes through the film thickness gauge 9 and enters the longitudinal stretching system 10, and is subjected to 4.5 times longitudinal stretching at 100° C. to obtain a longitudinal stretched film.

[0126] The longitudinally stretched film is coated on both sides with an aqueous polym...

Embodiment 2

[0130] Embodiment 2 is the same as Embodiment 1, and the only difference is that the longitudinal stretch film is coated with Nafion solution (purchased from DuPont) on one side surface through the coating system (II), and the thickness of the coating after drying is 3 microns. Stretching to obtain a single-sided coated composite polypropylene microporous membrane of Nafion with a non-porous compact structure on one side surface.

[0131] The thickness of the coating layer is 1.0 micron; the thickness of the composite polypropylene microporous membrane is 19 micron.

[0132] When the composite polypropylene microporous membrane prepared above is used as a lithium-sulfur battery separator, since the Nafion layer on the surface has a non-porous and compact structure, polysulfides dissolved in the electrolyte cannot be transported through the separator, while lithium ions can Combined with the sulfonate in Nafion for transport, the composite polypropylene microporous membrane can...

Embodiment 3

[0134] Embodiment 3 is the same as Embodiment 1, the difference is only that the xylene solution of polydimethylsiloxane is coated on one side of the longitudinally stretched film through the second coating system, and the thickness of the coating after drying is 6 microns. A composite polypropylene microporous membrane coated on one side of polydimethylsiloxane with non-porous compact structure is obtained through transverse stretching.

[0135] The thickness of the coating layer is 2 microns; the thickness of the composite polypropylene microporous membrane is 20 microns.

[0136] The composite polypropylene microporous membrane prepared above is used as a gas separation membrane to separate ethanol / water solution by pervaporation, and a good separation effect is obtained.

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Abstract

The invention discloses a composite polypropylene microporous membrane, and a preparation method and application thereof, and provides a device for preparing the composite polypropylene microporous membrane. According to the preparation method, a coating layer is introduced to the surface of one side or both sides of a membrane slice by a coating system during preparation of a biaxially oriented polypropylene microporous membrane, and the coating layer is stretched in both longitudinal and transverse directions or only in the transverse direction to achieve the preparation of the composite polypropylene microporous membrane. The method simplifies the production process of the composite polypropylene microporous membrane and improves the performance of the polypropylene microporous membrane. The composite polypropylene microporous membrane is used in a lithium battery, and since the coating layer is a polymer or a composition capable of forming a gel with an electrolyte, the cycle and safety performance of the lithium battery can be improved. The composite polypropylene microporous membrane is used for gas separation, and separation and enrichment of different gases can be achieveddue to different permeability coefficients of the coating layer to different gases.

Description

technical field [0001] The invention belongs to the technical field of microporous membranes, and in particular relates to a composite polypropylene microporous membrane and its preparation method and application. Background technique [0002] Polyolefin microporous membrane is a kind of polymer membrane, which is a porous membrane with a pore size between 5nm and 1000nm. It is widely used in breathable materials such as diapers, medical dressings, clothing linings, etc., and materials for liquid separation. , ultrafiltration materials, membrane filtration materials, and supercapacitor and battery diaphragm materials and other fields. [0003] There are mainly two methods for preparing polyolefin microporous membranes, one is melt extrusion stretching method (dry method), and the other is thermally induced phase separation method (TIPS, wet method). Among them, the dry stretching process can also be divided into a uniaxial stretching process and a biaxial stretching process...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J7/04C08J5/18C08L23/12C08K5/20H01M2/14H01M2/16H01M50/403H01M50/417H01M50/457H01M50/489
CPCC08J5/18C08J2323/12C08J2433/12C08J2483/04C08J7/0427H01M50/403H01M50/411H01M50/449Y02E60/10
Inventor 周建军李林胡志宇
Owner BEIJING NORMAL UNIVERSITY
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