Method for preparing tubular micro-porous filter membrane

A microporous membrane and tubular technology, applied in the field of membrane science, can solve the problems of low membrane support strength, uneven membrane thickness, and poor integrity, and achieve stable membrane performance, uniform pore size distribution, and good integrity

Active Publication Date: 2014-09-10
JIANGSU KAIMI MEMBRANE TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a method for preparing a tubular microporous membrane to solve the problems of poor integrity, low membrane support strength, uneven membrane thickness and structural defects existing in the existing tubular microporous membrane

Method used

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Examples

Experimental program
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Effect test

preparation example Construction

[0028] A kind of preparation method of tubular microporous membrane of the present invention comprises the following steps:

[0029] (1) Preparation of basement membrane casting solution: mix polymer, additives, and solvent, stir at 50-80°C for 12-48 hours until all components are completely dissolved, leave in vacuum and defoam to obtain high-concentration Basement membrane casting solution;

[0030] The mass fractions of each component in the basement membrane casting solution are:

[0031] Polymer 18~30%, additive 1~15%, solvent 55~81%;

[0032] The polymer is polyvinylidene fluoride, nitrocellulose, polysulfone, polyacrylonitrile, polyvinyl acetate or a mixture of two or more mixed in any proportion; the additive is polyvinylpyrrolidone, polyethylene Diol, hydroxyethyl methacrylate, polyvinyl alcohol, lithium chloride, ammonium chloride, or a mixture of two or more in any proportion; the solvent is selected from N,N-dimethylformamide , N,N-dimethylacetamide, dimethyl su...

Embodiment 1

[0044] (1) Preparation of basement membrane casting solution: put 18% polyvinylidene fluoride, 8% polyvinylpyrrolidone, 4% polyethylene glycol, and 70% N,N-dimethylformamide in a tube In the batching tank of the type film forming machine, stir at a stirring speed of 300r / min and a constant temperature of 65°C for 18 hours until the components are completely dissolved, then seal and stand for 48 hours under vacuum conditions, and obtain a high-concentration casting of the base film after complete defoaming. Membrane fluid;

[0045] (2) Preparation of separation layer casting solution: put 12% polyvinylidene fluoride, 4% polyoxyethylene, and 84% N,N-dimethylformamide in the other part of the tubular film forming machine in mass percentage. In the batching tank, stir at a stirring speed of 300r / min and a constant temperature of 65°C for 18h until each component is completely dissolved, then seal and stand for 24h under vacuum conditions, and obtain a low-concentration casting sol...

Embodiment 2

[0049] (1) with embodiment 1;

[0050] (2) Preparation of the separation layer casting solution: the mass percentage is composed of 15% polyvinyl acetate, 4% polyethylene glycol, and 81% acetone in another batching tank of the tubular film forming machine, with 300r / Min stirring speed, 65 ℃ constant temperature stirring for 18 hours, until each component is completely dissolved, sealed and left for 24 hours under vacuum conditions, after complete defoaming, a low-concentration casting solution of the separation layer is obtained;

[0051] (3) with embodiment 1;

[0052] (4) Preparation of tubular microporous membrane: Squeeze out the separation layer casting solution obtained in step (2) from the central metal tube, and evenly coat it in step (3) at a coating speed of 0.8m / min. On the inner surface of the prepared base membrane, let stand in the air for 300s, soak in pure water at 35° C. for 48 hours, solidify to form a membrane, and obtain a tubular microporous membrane.

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Abstract

The invention discloses a method for preparing a tubular micro-porous filter membrane. The method comprises the following steps: (1) preparing a base membrane casting solution, namely mixing a polymer, an additive and a solvent until each component is completely dissolved, standing in vacuum, and defoaming, thereby obtaining the base membrane casting solution; (2) preparing a separation layer casting membrane solution, namely mixing a polymer, an additive and a solvent until each component is completely dissolved, standing in vacuum, and defoaming, thereby obtaining the separation layer casting membrane solution; (3) preparing a base membrane, namely coating by placing the base membrane casting solution prepared in the step (1) and a non-woven fabric on a tubular coating machine, thereby obtaining the base membrane; and (4) preparing the tubular micro-porous filter membrane, namely putting the separation layer casting membrane solution prepared in the step (2) on the tubular coating machine, uniformly coating the inner surface of the base membrane prepared in the step (3) with the separation layer casting membrane solution to form a polymer seepage filter layer with concentration gradient, standing in air, immersing in a coagulating bath, and performing phase inversion separation. The prepared tubular micro-porous filter membrane is uniform in thickness, uniform in pore size distribution and complete without defects.

Description

technical field [0001] The invention belongs to the field of membrane science and technology, and in particular relates to a preparation method of a tubular microporous membrane. Background technique [0002] Ultra / microfiltration technology is a kind of membrane separation technology. The membrane is mostly porous and asymmetric structure. It is a separation process based on the pressure difference on both sides of the membrane as the mass transfer power and the principle of mechanical sieving. It has normal temperature operation, The process has no phase change, low energy consumption, and high separation precision. It has been widely used in industrial water treatment, beverage, food, medicine, environmental protection, chemical industry, metallurgy, petroleum, etc. [0003] At present, the membrane preparation methods mainly include melt stretching method, dry-wet immersion non-solvent-induced phase inversion method, thermal phase separation method, etc. For the same mem...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D69/04B01D71/34B01D71/20B01D71/68B01D71/42B01D71/48B01D67/00
Inventor 云金明王怀林关晓琳岑彩荣尹燕亓时良晶
Owner JIANGSU KAIMI MEMBRANE TECH
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