Polyethylene microporous film and preparation method and application thereof

A polyethylene microporous film and polyethylene resin technology, applied in the field of microporous film, can solve problems such as extremely poor air permeability

Active Publication Date: 2019-08-23
乐凯胶片股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When the microporous membrane obtained by the current preparation method has a large transverse width, the air permeability in the transverse direction is still relatively large, which is far from meeting the actual production needs.

Method used

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  • Polyethylene microporous film and preparation method and application thereof
  • Polyethylene microporous film and preparation method and application thereof
  • Polyethylene microporous film and preparation method and application thereof

Examples

Experimental program
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preparation example Construction

[0024] The preparation method of the present invention comprises the steps:

[0025] 1) Blending polyethylene resin and diluent paraffin oil into a twin-screw extruder, and then rapidly cooling it through a casting roll to make it phase-separated rapidly, and obtaining a thick sheet with a semi-elliptical cross-section, such as Figure 4 shown in (a); rather than thick slices with regular triangular cross-sections, undulating wavy lines, triangular protrusions or triangular depressions, respectively, as shown in Figure 4 (b), (e), (c) and (d) in. The extreme difference in thickness / width of the slab is controlled at 100-300um / 500mm;

[0026] 2) The thick sheet is stretched longitudinally (MDO) by means of gradient increasing speed, and the roll speed ratio of two adjacent stretching rolls is controlled at 1.1-1.2;

[0027] 3) Both sides of the film after longitudinal stretching are fixed with clamps, and the first transverse stretching (TDO1) is carried out, and the stretching ...

Embodiment 1

[0031] 1) Polyethylene resin and thinner paraffin oil are blended into a twin-screw extruder according to a mass ratio of 28:72, and the average molecular weight of the polyethylene resin is 500,000, and are transported to the extrusion die through a metering pump. The head temperature was set at 200°C. Afterwards, the casting roll is extremely cold to make it phase-separate rapidly, and a thick sheet is obtained. The thickness of the thick sheet is extremely poor / width is controlled at 140um / 500mm;

[0032] 2) The thick sheet is stretched longitudinally (MDO) in a manner of gradient increase in speed, the stretching temperature is 110°C, and the roll speed ratio of two adjacent stretching rolls is controlled at 1.11;

[0033] 3) Then both sides of the film are fixed with clamps, and the first transverse stretching (TDO1) is carried out, the transverse stretching ratio is 7 times, and the stretching temperature is 123°C;

[0034] 4) The obtained microporous oil film is extrac...

Embodiment 2

[0038] 1) Polyethylene resin and diluent paraffin oil are blended into a twin-screw extruder according to the mass ratio of 30:70, and the average molecular weight of the polyethylene resin is 700,000, and are transported to the extrusion die through a metering pump. The head temperature was set at 200°C. Afterwards, the casting roller is extremely cold to make it phase-separated rapidly, and a thick sheet is obtained, and the thickness of the thick sheet is extremely poor / width is controlled at 130um / 500mm;

[0039] 2) The slab is longitudinally stretched (MDO) in a manner of gradient increasing speed, and the stretching temperature is 120°C. In the longitudinal stretching mode, the roll speed ratio of the stretching roller is 1.13;

[0040] 3) Then both sides of the film are fixed with clamps, and the first transverse stretching (TDO1) is carried out, the transverse stretching ratio is 7.6 times, and the stretching temperature is 122°C;

[0041] 4) The obtained microporous...

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Abstract

The invention relates to a polyethylene microporous film and a preparation method and an application thereof. The preparation method comprises steps that the polyethylene resin is melt and blended with diluent; the melt blended treated product is subjected to molding and cooling treatment to obtain a sheet having a predetermined-shape cross section; the sheet is subjected to longitudinal stretching treatment and transverse stretching treatment to obtain a base film; the base film is post-treated to obtain a polyethylene microporous film, and longitudinal stretching treatment is performed by means of a gradient increasing speed, roller speed ratios of adjacent two stretching rolls are equal and are in a range of 1.1-1.2, transverse stretching treatment is performed at the temperature of 120-130 DEG C, and a ratio of the thickness difference to the width of the sheet is (100~300 mum)/500 mum. The preparation method is advantaged in that the prepared polyethylene microporous film has gaspermeability difference of 30 s/100 cc in the transverse width (3 to 5 m) direction, and the qualification rate is high.

Description

technical field [0001] The present invention relates to the field of microporous membranes. Specifically, the present invention relates to polyethylene microporous membranes and their preparation methods and applications. More specifically, the present invention relates to the preparation methods of polyethylene microporous membranes, polyethylene microporous membranes and lithium ion Battery. Background technique [0002] When the microporous membrane is prepared by wet heat-induced phase separation method, it includes four stages of casting, longitudinal drawing MDO, first transverse drawing TDO1 and second transverse drawing heat setting (TDO2). Among them, casting sheet, longitudinal drawing MDO and the first horizontal stretching TDO1 are mainly at the stage of microporous membrane pore formation, and the second horizontal stretching heat setting (TDO2) is mainly to restore the microporous state of horizontal stretching. The process that causes the extreme difference i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/14H01M2/16H01M10/0525
CPCH01M10/0525H01M50/403H01M50/411Y02E60/10
Inventor 王月勤千昌富胡玉涛周世蛟王莉李茜茜柳青
Owner 乐凯胶片股份有限公司
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