Vinylidene fluoride resin hollow fiber porous membrane and process for producing same

A technology of ethylene difluoride and porous membrane, which is applied in chemical instruments and methods, membranes, membrane technology, etc., and can solve the problems of excessively large average pore size and water permeability maintenance of hollow fiber porous membranes

Inactive Publication Date: 2012-02-08
KUREHA KAGAKU KOGYO KK
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

From this point of view, the average pore size of the hollow fiber porous membrane disclosed in the following patent document 4 is too large, and the hollow fiber porous membrane disclosed in the following patent document 6 has problems in maintaining the permeable amount in the continuous filtration operation of turbid water. question

Method used

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  • Vinylidene fluoride resin hollow fiber porous membrane and process for producing same
  • Vinylidene fluoride resin hollow fiber porous membrane and process for producing same
  • Vinylidene fluoride resin hollow fiber porous membrane and process for producing same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0077] Using a Henschel mixer, the weight average molecular weight (Mw) was 4.12×10 5 The main body polyvinyl difluoride (PVDF) (powder) and Mw is 9.36×10 5 Polyvinylidene fluoride (PVDF) (powder) for modifying the crystallization properties of the polyvinyl difluoride (PVDF) is mixed with a ratio of 95% by weight and 5% by weight respectively, and the obtained Mw is 4.38×10 5 Mixture A.

[0078] An adipic acid-based polyester plasticizer ("PN-150" manufactured by Asahi Denka Co., Ltd.) as an aliphatic polyester and N-methylpyrrolidone (NMP) as a solvent were mixed at 82.5% by weight / 17.5% by weight The ratio is stirred and mixed at room temperature to obtain mixture B.

[0079] Using a co-rotating interlocking twin-screw extruder ("BT-30" manufactured by Plastic Engineering Research Institute, screw diameter 30mm, L / D=48), according to the ratio of mixture A / mixture B=34.4 / 65.6 (weight %) Ratio, the mixture A is supplied from the powder supply part installed at a position ...

Embodiment 2

[0085] A hollow fiber porous membrane was obtained in the same manner as in Example 1 except that the draw ratio of the second intermediate molded product was increased from 2.4 times to 2.8 times.

Embodiment 3

[0087] Except having changed the water bath temperature into 55 degreeC, it carried out similarly to Example 1, and obtained the hollow fiber porous membrane.

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PUM

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Abstract

Disclosed is a vinylidene fluoride resin hollow fiber porous membrane characterized by comprising a vinylidene fluoride resin porous membrane in the form of hollow fibers, and having a ratio of the maximum pore diameter (Pmax) to the average pore diameter (Pm) (i.e., a Pmax / Pm ratio) of 2.0 or less as measured by a half-dry / bubble-point method (ASTM F316 and ASTM E1294), a Pm of 0.13 to 0.25 [mu]m, a coefficient of variation in pore diameter on the outer surface of 70% or less, and a porosity of 75 to 90%. In the hollow fiber porous membrane, the average pore diameter is proper, the pore diameter distribution on the whole and the outer surface is uniform, and the porosity is high. Therefore, the hollow fiber porous membrane has good permeability to pure water, as well as an ability to maintain good permeability during the continuous filtration of muddy water. The hollow fiber porous membrane can be produced by a process comprising melt-extruding a vinylidene fluoride resin together with a plasticizer and a good solvent for the vinylidene fluoride resin into follow fibers, cooling the resulting product, shaping the cooled material into a membrane, extracting the plasticizer and the good solvent from the membrane, and stretching the membrane at a temperature ranging from 80 to 95 DEG C, which is higher and limited compared with the temperatures employed in the conventional processes, without carrying out any heat treatment for crystallization.

Description

technical field [0001] The present invention relates to a hollow-fiber porous membrane made of vinylidene fluoride resin (a hollow-fiber porous membrane) excellent in (filtrated) water treatment performance, and a method for producing the same. Background technique [0002] Since 1,1-vinylidene fluoride resins are excellent in weather resistance, chemical resistance, and heat resistance, their application to porous membranes for separation has been studied. In the case of (filtered) water treatment, especially tap water production or sewage treatment, hollow fiber porous membranes that are easy to increase the membrane area per unit volume of filtration devices are often used, including their manufacturing methods, and it has been proposed Many proposals have been proposed (for example, the following patent documents 1 to 4). [0003] In addition, the present inventors have also found that a hollow fiber can be obtained by melt-extruding a 1,1-vinylidene fluoride resin havi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D71/34B01D69/08C08J9/26D01F6/12
CPCB01D67/002B01D67/0027B01D67/003B01D67/0095B01D69/02B01D69/08B01D71/34B01D2325/02B01D2325/34C02F1/444C02F3/1273Y02W10/10
Inventor 高桥健夫多田靖浩海老原康志
Owner KUREHA KAGAKU KOGYO KK
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