Ultrathin high-strength polyolefin microporous film and preparation method thereof

A polyolefin microporous film, polyolefin technology, applied in the direction of coating, can solve the problems of easy thermal oxidation, mechanical degradation, lower yield, easy carbonization of polyolefin resin, etc., to ensure anti-oxidation effect, easy process flow The effect of simple operation and process flow

Active Publication Date: 2014-07-16
SHENZHEN SENIOR TECH MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the molecular chain of polyolefin resin is relatively long and it is a non-polar crystalline polymer. In the stage of melting and heating, due to the effect of high temperature and strong shear, the molecular chain of polyolefin is easy to be thermally oxidized and mechanically degraded, which makes the chemical bonds of the molecular chain Break into active free radicals and hydroperoxides, and hydroperoxides are further decomposed to produce alkoxyl radicals and hydroxyl radicals, leading to a series of free radical chain reactions that cause fundamental changes in the structure and properties of polyolefin resins

Method used

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  • Ultrathin high-strength polyolefin microporous film and preparation method thereof
  • Ultrathin high-strength polyolefin microporous film and preparation method thereof

Examples

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Example Embodiment

[0026] A preparation method of ultra-thin high-strength polyolefin microporous membrane, which uses polyolefin resin as a raw material and adopts the principle of thermally induced phase separation to prepare a polyolefin porous membrane, including the following steps:

[0027] a. Polyolefin swelling and dissolution: Dissolve the antioxidant in the diluent in a kneader, add polyolefin resin powder to the diluent, stir uniformly, and under the protection of nitrogen, heat up to 80°C-150°C to keep swelling to obtain Swelling polyolefin; under the protection of nitrogen, add diluent to the swelling polyolefin and dissolve at 100-400℃ to form a mixture;

[0028] b. Casting: The mixture obtained in the previous step is fed into the extruder by a gear pump, the extruder is used to plasticize the mixture to form a polyolefin solution, and the obtained polyolefin solution is extruded from the die under the control of the metering pump , To obtain a polyolefin melt;

[0029] c. Polyolefin ca...

Example Embodiment

[0039] Example 1

[0040] (1) Under the protection of nitrogen, first dissolve the antioxidant in the diluent, and then add the polyolefin resin and diluent to the kneader to swell and dissolve. The mass ratio of antioxidant to polyolefin resin is 1:8000, the mass ratio of polyolefin to diluent is 1:3, the swelling temperature is 100°C, and the dissolving temperature is 250°C.

[0041] In this embodiment, the antioxidant is dioctadecyl pentaerythritol bisphosphite, the polyolefin resin is an ultra-high molecular weight polyethylene resin with a weight average molecular weight of 2 million, and the diluent is paraffin oil.

[0042] (2) The swelling and dissolving mixture is fed into the extruder by a gear pump, and a uniform melt is obtained through mixing, dispersion and shearing. The quench roll is cooled to form a sheet, and the product is made into a polyethylene microporous film after biaxial stretching, extraction and drying. The temperature of the extruder is 100-300°C, and t...

Example Embodiment

[0043] Example 2

[0044] (1) Under the protection of nitrogen, first dissolve the antioxidant in the diluent, and then add the polyolefin resin and the diluent to the kneader to swell and dissolve. The mass ratio of antioxidant to polyolefin resin is 1:8000, the mass ratio of polyolefin to diluent is 1:3, the swelling temperature is 100°C, and the dissolving temperature is 250°C.

[0045] In this embodiment, the antioxidant is dioctadecyl pentaerythritol bisphosphite, the polyolefin resin is an ultra-high molecular weight polyethylene resin with a weight average molecular weight of 5 million, and the diluent is paraffin oil.

[0046] (2) The swelling and dissolving mixture is fed into the extruder by a gear pump, and a uniform melt is obtained through mixing, dispersion and shearing. The quench roll is cooled to form a sheet, and the product is made into a polyethylene microporous film after biaxial stretching, extraction and drying. The temperature of the extruder is 100-300°C, a...

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Abstract

The invention discloses a preparation method of an ultrathin high-strength polyolefin microporous film. Polyolefin resin is used as a raw material, and the polyolefin microporous film is prepared by a thermally induced phase separation principle. The method comprises the following steps: a. polyolefin swelling dissolving; b. sheet casting; c. stretching a polyolefin cast film once; and d. stretching the polyolefin cast film secondarily. The invention also discloses the polyolefin microporous film prepared by the method. The method has the advantages of semi-continuous production convenience, simple process flow and simplicity in operation.

Description

technical field [0001] The invention relates to a lithium-ion secondary battery, in particular to a preparation method of an ultra-thin high-strength polyolefin microporous membrane capable of convenient semi-continuous production and simple and easy-to-operate process flow and the polyolefin microporous membrane. Background technique [0002] Due to the good chemical stability and excellent physical properties of polyolefin, its microporous membrane separator is widely used in the fields of batteries, capacitors, water treatment, water desalination, biomedical and medical applications, especially as a separator for lithium-ion batteries. In the prior art, methods for preparing polyolefin microporous membranes include dry process (uniaxial stretching and biaxial stretching) and wet process (thermally induced phase separation method). Compared with other methods, the wet process can produce thinner microporous membranes with uniform thickness and excellent physical properties...

Claims

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Application Information

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IPC IPC(8): B29C69/00B29C47/00B29C55/12B29C41/26C08L23/06C08K5/524
Inventor 王郗肖武华刘瑞高东波
Owner SHENZHEN SENIOR TECH MATERIAL
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