Polypropylene microporous membrane with three-layer compound structure and preparation method thereof

A polypropylene microporous film, three-layer structure technology, applied in the field of microporous film, can solve problems such as poor safety and inability to ensure battery safety, achieve low closed-cell temperature, prevent abnormal battery temperature rise, and avoid internal short circuits Effect

Inactive Publication Date: 2014-08-20
昆明云天化纽米科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although these two polypropylene microporous membranes have high porosity and good permeability, they are less safe when used as battery separators. The main manifestations are: due to the high melting point of polypropylene, the micropores melt and close. The temperature is high. When the abnormal reaction of the battery causes the temperature to rise abnormally, the polypropylene microporous membrane cannot melt and close the cells in time to terminate the battery reaction, so that the safety of the battery cannot be guaranteed.

Method used

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  • Polypropylene microporous membrane with three-layer compound structure and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0023] 1) 0.1% by weight of terephthalic acid, 0.1% by weight of barium oxide and 99.8% by weight of homopolypropylene were mixed and extruded to obtain β-crystal homopolypropylene, and its β-crystal content was measured to be 82%, the melt index is 8, the crystallinity is 62%, and the melting point is 165°C.

[0024] 2) 0.1% by weight of terephthalic acid, 0.1% by weight of barium oxide and 99.8% by weight of ethylene-propylene copolymerized polypropylene were mixed and extruded to obtain β-crystal copolymerized polypropylene, and the content of β-crystal form was measured to be 79%, the melt index is 15, the crystallinity is 51%, and the melting point is 141°C.

[0025] 3) The above-mentioned β-crystal homopolypropylene is used as the raw material of the surface layer A and surface layer C, and the above-mentioned β-crystal copolymerized polypropylene is used as the raw material of the core layer B, which are respectively melted and kneaded at 220°C and then compounded by th...

Embodiment 2

[0029] 1) Mix and extrude 0.5% by weight of azelaic acid, 1% by weight of calcium stearate and 98.5% by weight of homopolypropylene to obtain β-crystal homopolypropylene, and measure its β-crystal content It is 89%, the melt index is 7, the crystallinity is 60%, and the melting point is 162°C.

[0030] 2) Mix and extrude 0.5% by weight of azelaic acid, 1% by weight of calcium stearate and 98.5% by weight of ethylene-propylene-butylene ternary copolymerized polypropylene to obtain β-crystalline copolymerized polypropylene, and measure its β-crystalline The molar content is 78%, the melt index is 16, the crystallinity is 44%, and the melting point is 140°C.

[0031] 3) The above-mentioned β-crystal copolymerized polypropylene is used as the raw material of the surface layer A and the surface layer C, and the above-mentioned β-crystal homopolypropylene is used as the raw material of the core layer B, which are respectively melted and kneaded at 210°C and then compounded by three ...

Embodiment 3

[0035] 1) 1% by weight of adipic acid, 2% by weight of calcium carbonate and 97% by weight of homopolypropylene were mixed and extruded to obtain β-crystal homopolypropylene I, and its β-crystal content was measured to be 88%, the melt index is 6.5, the crystallinity is 58%, and the melting point is 163°C. 1.5% by weight of phthalimide, 3% by weight of magnesium oxide and 95.5% by weight of homopolypropylene were mixed and extruded to obtain β-crystal homopolypropylene II, and its β-crystal content was measured It is 85%, the melt index is 7.2, the crystallinity is 60%, and the melting point is 160°C.

[0036] 2) Mix and extrude 1% by weight of adipic acid, 2% by weight of calcium carbonate and 97% by weight of ethylene-propylene-butylene ternary copolymerized polypropylene to obtain β-crystal form copolymerized polypropylene, and measure its β-crystal form content It is 80%, the melt index is 18, the crystallinity is 43%, and the melting point is 138°C.

[0037] 3) The above-...

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Abstract

The invention discloses a polypropylene microporous membrane with a three-layer compound structure and a preparation method of the polypropylene microporous membrane. The polypropylene microporous membrane with the three-layer compound structure comprises surface layers A and C and a core layer B, wherein the surface layers A and C are made from beta crystal form homo-polypropylene and the core layer B is made from beta crystal form co-polypropylene; or, the surface layers A and C are made from beta crystal form co-polypropylene and the core layer B is made from beta crystal form homo-polypropylene. The preparation method comprises the following steps: (1) respectively melting and mixing the beta crystal form homo-polypropylene and the beta crystal form co-polypropylene, carrying out co-extrusion via a three-layer compound die head and cooling the extruded molten membrane; and (2) stretching the three-layer compound beta crystal form polypropylene membrane. The polypropylene microporous membrane with the three-layer compound structure, disclosed by the invention, has high fusing temperature and low closed pore temperature simultaneously and has the advantages that when the membrane is used for battery diaphragms, closed pores can be timely molten to terminate the battery reaction and the internal short caused by fusing can be avoided, so that the safety is greatly increased.

Description

technical field [0001] The invention belongs to the technical field of microporous membranes, in particular to a polypropylene microporous membrane with a three-layer composite structure and a preparation method thereof. Background technique [0002] Microporous membrane is a very versatile filter medium, which can be used for gas separation, reverse osmosis, nanofiltration, ultrafiltration and microfiltration according to the different pore sizes of microporous membranes. Due to its low price, excellent mechanical properties and chemical corrosion resistance, polyolefin microporous membranes are widely used in capacitor separators, battery separators and various separation membranes. In the known technology, the existing preparation methods of polyolefin microporous membranes mainly include melt stretching method and thermally induced phase separation method. The melt stretching method includes melting the polymer, extruding into a film, annealing to increase the lamella ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D69/12B01D71/26B01D67/00
Inventor 谢新春王志春
Owner 昆明云天化纽米科技有限公司
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