Polyolefin microporous membrane and preparation method thereof

A technology of polyolefin microporous membrane and microporous membrane, which is applied in the direction of electrical components, electrochemical generators, circuits, etc., can solve the problem of low surface tension coefficient, failure to meet the requirements of use, and inability to effectively increase the surface tension coefficient, etc. problems, to achieve the effect of improving the surface tension coefficient, ensuring safety and energy density

Active Publication Date: 2018-12-21
HEFEI XINGYUAN NEW ENERGY MATERIAL CO LTD
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  • Abstract
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  • Application Information

AI Technical Summary

Problems solved by technology

[0005] However, the preparation of polyolefin microporous membranes by the wet process also has many disadvantages: the polyolefin microporous membranes prepared by the wet process need to be coated (such as coating ceramic powder) or have good wettability with the electrolyte to meet the requirements of lithium ionization. The safety and energy density of ion batteries, due to the low surface tension coefficient of polyolefin microporous membranes, are prone to two problems. The wettability of the polyolefin microporous membrane and the electrolyte is poor during use, and these two problems seriously affect the safety and energy density of lithium-ion batteries
Corona treatment can improve the surface tension coefficient of polyolefin microporous membrane to a certain extent, but the discharge generated by high output corona will break down the polyolefin microporous membrane or destroy the microporous structure, which will affect the lithium ion The safety of the battery, and the discharge generated by the corona with low output power cannot effectively increase the surface tension coefficient, which cannot meet the requirements of use

Method used

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  • Polyolefin microporous membrane and preparation method thereof
  • Polyolefin microporous membrane and preparation method thereof
  • Polyolefin microporous membrane and preparation method thereof

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preparation example Construction

[0028] The invention provides a method for preparing a polyolefin microporous membrane, which includes the following steps:

[0029] (1) The polyolefin resin and diluent are melted and blended in a twin-screw extruder, extruded from the die, and the cast sheet is cooled by the casting roll, and then biaxially stretched, extracted, and dried to prepare Microporous membrane A;

[0030] (2) In the presence of the photosensitizer, use a low-pressure mercury lamp to irradiate the surface of the microporous membrane A to obtain the microporous membrane B;

[0031] (3) The microporous membrane B is subjected to transverse heat setting treatment to obtain the microporous membrane C;

[0032] (4) The microporous film C is corona treated with a corona treatment machine to obtain a polyolefin microporous film.

[0033] Preferably, the weight ratio of the polyolefin resin to the diluent is 1:1-9, and more preferably, the weight ratio of the polyolefin resin to the diluent is 1:2-6.

[0034] Prefera...

Embodiment 1

[0045] (1) UHMWPE with a weight ratio of 1:3 (average molecular weight of 2×10 6 ) And paraffin oil are melted and blended in a twin-screw extruder at an extrusion temperature of 190℃, extruded from a die, and the cast sheet is cooled by a casting roll at a temperature of 40°C, and the cast sheet is biaxially stretched , Where the stretching ratio is longitudinal × transverse = 5 × 7 times, and then subjected to extraction post-drying treatment in heptane at 25°C to obtain microporous membrane A;

[0046] (2) In the presence of benzophenone, the surface of the microporous membrane A is irradiated with ultraviolet light with a wavelength of 254nm generated by a low-pressure mercury lamp for 1 min to obtain microporous membrane B, where the gap between the low-pressure mercury lamp and the microporous membrane A Is 200mm;

[0047] (3) The microporous film B was heat-set at a rate of 1.2 in a transverse stretching oven at 140°C to obtain the microporous film C;

[0048] (4) The micropo...

Embodiment 2

[0050] (1) UHMWPE with a weight ratio of 1:2 (average molecular weight of 3×10 5 ) And diisobutyl adipate are melted and blended in a twin-screw extruder with an extrusion temperature of 160°C, extruded from a die, and the cast sheet is cooled by a casting roll at a temperature of 10°C, and the cast sheet Perform biaxial stretching, where the stretching ratio is longitudinal × transverse = 3 × 5 times, and then perform extraction and post-drying treatment in acetone at 15° C. to obtain microporous membrane A;

[0051] (2) In the presence of benzophenone, irradiate the surface of the microporous membrane A with ultraviolet light with a wavelength of 180nm generated by a low-pressure mercury lamp for 2 minutes to obtain microporous membrane B. The gap between the low-pressure mercury lamp and the microporous membrane A Is 100mm;

[0052] (3) The microporous film B is heat-set at a rate of 1 in a transverse stretching oven at 100°C to obtain the microporous film C;

[0053] (4) The mic...

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Abstract

The invention discloses a preparation method of polyolefin microporous membrane. The method comprises the following steps that polyolefin resin and a diluent are subjected to fusion and blending in atwin-screw extruder, extrudate is extruded from a die head, through a casting roll, a casting piece is cooled, and then after two-way stretching, extraction and drying are conducted, microporous membrane A is prepared; in the presence of a photosensitizer, a low pressure mercury lamp is used for conducting irradiation on the surface of the microporous membrane A to obtain microporous membrane B; the microporous membrane B is subjected to transverse thermoforming treatment to obtain microporous membrane C; the microporous membrane C is subjected to corona treatment by means of a corona treaterto obtain the polyolefin microporous membrane. After the polyolefin resin is subjected to wet processing, before a rolling procedure, through ultraviolet light irradiation and corona, the polyolefin microporous membrane is subjected to two-time surface treatment, under a condition of not destructing a polyolefin microporous membrane microporous structure, a surface tension coefficient of the microporous membrane is increased, and the polyolefin microporous membrane with a high surface tension coefficient is prepared, so that the safety and the energy density of a lithium battery are improved.

Description

Technical field [0001] The invention relates to the technical field of microporous membrane production, in particular to a polyolefin microporous membrane and a preparation method thereof. Background technique [0002] With the process of economic globalization and the massive use of fossil fuels, the problems of environmental pollution and energy shortages have become increasingly prominent. In order to reduce pollution from the use of fossil fuels, the development of sustainable renewable energies for wind, light, and electricity, new power batteries and high-efficiency energy storage systems, and realizing the reasonable allocation of renewable energy are essential for improving resource utilization efficiency, solving energy crises and protecting the environment. Has important strategic significance. [0003] The deterioration of the environment and the energy crisis have caused widespread concern around the world. The new energy industry represented by the new energy automob...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J7/12C08J5/18C08L23/06C08L91/06C08K5/12C08K5/01C08K5/11H01M2/14H01M2/16H01M10/0525H01M50/403H01M50/417H01M50/489
CPCH01M10/0525C08J5/18C08J7/123C08J2323/06C08J2491/06C08K5/12C08K5/11C08K5/01H01M50/403H01M50/411Y02E60/10
Inventor 李旦王郗林敬
Owner HEFEI XINGYUAN NEW ENERGY MATERIAL CO LTD
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