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Method for preparing polyvinylidene fluoride microporous filtering film

A technology of polyvinylidene fluoride and microporous membrane, which is applied in chemical instruments and methods, membrane technology, semi-permeable membrane separation, etc., can solve the problem of low performance and mechanical strength, uneven pore structure in the membrane, uneven With the separation membrane structure and other problems, it can reduce the harm to the environment and human body, have good penetration and high pure water flux.

Active Publication Date: 2008-08-06
SHUANGJIE HIGH TECH DEV JILIN CITY
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the membrane made with the above-mentioned diluent has uneven pore structure and loosely packed spherulites, which does not have an ideal separation membrane structure.
In addition, the performance and mechanical strength of the film are not very high, and phthalates, cyclohexanone and γ-butyrolactone are all toxic to a certain extent, and the diluent that acts as a pore in the film needs to be organic. Solvent extraction is harmful to the environment and people

Method used

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  • Method for preparing polyvinylidene fluoride microporous filtering film
  • Method for preparing polyvinylidene fluoride microporous filtering film
  • Method for preparing polyvinylidene fluoride microporous filtering film

Examples

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preparation example Construction

[0025] The preparation method of the polyvinylidene fluoride microporous filter membrane of the present invention is carried out according to the following steps:

[0026] (1) Mix the polyvinylidene fluoride resin with the diluent. The content of the polyvinylidene fluoride resin in the mixture is 10-60% by weight, preferably 20-40% by weight; the above-mentioned mixture is sealed in a stirring container filled with nitrogen, Raise the temperature to 140~220℃ (below the boiling point of the diluent), mechanically stir or use twin-screw shear stirring to form a homogeneous polymer solution;

[0027] (2) Spread the homogeneous polymer solution obtained above uniformly on a mold for casting (with a scraper if necessary), and cool down naturally in the air or put it in a certain medium directly to quench it, so that the film-forming liquid will have phases. Separation and solidification of polyvinylidene fluoride;

[0028] (4) Use water as the extractant to extract the diluent in the ...

Embodiment 1

[0033] Example 1. Preparation of Microporous Membrane by Polyvinylidene Fluoride and Ethylene Glycol Ether Acetate System

[0034] Mix the polyvinylidene fluoride resin (weight average molecular weight 226,000) with a mass percentage of 20% and ethylene glycol ethyl ether acetate with a mass percentage of 80%, and then add polyvinylidene fluoride with a mass percentage of 3%. Ethylene glycol (molecular weight 400) into the above mixture; then, the mixture was sealed in a stirring container filled with nitrogen, heated to 140 ℃, fully dissolved to a homogeneous solution; 6 hours later, stand at a constant temperature, degassing, The obtained homogeneous polymer solution is uniformly spread on a mold at the same temperature for molding. Naturally cool to 25°C. After cooling, put the mold into water to extract ethylene glycol ethyl ether acetate and polyethylene glycol. Change the water every 12 hours for a total of 3 to 4 times. After that, the formed membrane is taken out of the mo...

Embodiment 2

[0036] Example 2: Preparation of microporous filter membrane by polyvinylidene fluoride and ethylene glycol ethyl ether acetate system

[0037] Mix 30% by mass polyvinylidene fluoride (weight average molecular weight 226,000) and 70% by mass ethylene glycol ethyl ether acetate, and then add 3% polyvinylidene fluoride by mass. Diol (molecular weight 400) was added to the above mixture; then, the mixture was sealed in a stirring vessel filled with nitrogen, and the temperature was raised to 140° C. to fully dissolve to a homogeneous solution. After 6 hours, let it stand at a constant temperature and defoam, and spread the obtained homogeneous polymer solution evenly on a mold at the same temperature for molding. Quench in water to 25°C to solidify and form, and extract ethylene glycol ethyl ether acetate and polyethylene glycol. Change the water every 12 hours for a total of 3 to 4 times. After that, the formed membrane is taken out of the mold, and soaked in absolute ethanol for 2 t...

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Abstract

The invention discloses a method for preparing the micro-porous filter membrane of polyvinylidene fluoride, which includes the following steps: 1) polymer homogeneous phase solution is evenly spreaded on the die to be formed by casting; cooling makes the polyvinylidene fluoride to crystallize and solidify into the membrane; the polymer homogeneous phase solution contains the polyvinylidene fluoride and the diluent; 2) The diluent in the extraction disks is washed and dried to prepare the micro-porous membrane of polyvinylidene fluoride; wherein, the diluent is ethylene glycol monoethyl ether acetate or / and diacetine. The micro-porous membrane of polyvinylidene fluoride prepared by the invention has evenly distributed pore diameter and various pore structure with good penetration, thus avoiding the formation of the loose pore structure in membrane; the micro-porous membrane of polyvinylidene fluoride prepared by the invention also has high porosity rate and the surface does not have the obvious densification cortex with high pure water flux which can be widely applied to the areas such as chemical industry, environmental protection, biochemical pharmacy, medical health and industry water purification treatment.

Description

Technical field [0001] The invention relates to a preparation method of a polyvinylidene fluoride microporous filter membrane, in particular to a method for preparing a polyvinylidene fluoride microporous filter membrane by applying a thermally induced phase separation method. Background technique [0002] In the past ten years, the separation technology of microporous membranes has been widely used in the fields of chemical industry, environmental protection, biochemical pharmacy, medical and health, and industrial water purification treatment. The current production methods of microporous membranes include nuclear track etching, melt stretching, and non-solvent induced phase separation (NIPS). The nuclear track etching method is only suitable for the production of small-area flat membranes with an average pore diameter greater than 0.2μm; the pore size distribution of the membrane obtained by the melt stretching method is very wide, which affects its separation function; the no...

Claims

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Application Information

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IPC IPC(8): B01D71/34
Inventor 张强施艳荞陈观文
Owner SHUANGJIE HIGH TECH DEV JILIN CITY
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