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Vinylidene fluoride resin hollow filament porous membrane, water filtration method using the same, and process for producing said vinylidene fluoride resin hollow filament porous membrane

A technology of ethylene difluoride and porous membrane, which is applied in the field of 1, and can solve the problem that the hollow fiber porous membrane has not been developed.

Inactive Publication Date: 2008-02-06
KUREHA KAGAKU KOGYO KK
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] However, the existing reality is that a 1,1-vinylidene fluoride-based resin hollow fiber porous membrane suitable for regeneration by air washing has not been developed yet.

Method used

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  • Vinylidene fluoride resin hollow filament porous membrane, water filtration method using the same, and process for producing said vinylidene fluoride resin hollow filament porous membrane

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0101] The weight average molecular weight (Mw) is 4.12×10 5 The main body of polyvinyl difluoride (PVDF) (powder) with Mw is 9.36×10 5 Polyvinylidene fluoride (PVDF) (powder) is used for the modification of the crystallization characteristics of 95% by weight and 5% by weight respectively, and is mixed with a Henschel mixer to obtain a Mw of 4.38×10 5 Mixture A.

[0102] 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 The ratio of % by weight was stirred and mixed at room temperature to obtain a mixture B.

[0103] Using a co-rotating intermeshing twin-screw extruder ("BT-30" manufactured by Plastic Engineering Research Institute, screw diameter 30mm, L / D=48), the powder is supplied from the position 80mm from the most upstream part of the cylinder. Mixture A was supplied from the upper part, and mixture B heated to a temperatu...

Embodiment 2

[0110] The main body PVDF and the modified PVDF were mixed at a ratio of 90% by weight and 10% by weight respectively to obtain a Mw of 4.64×10 5 Mixture A.

[0111] Using this mixture A, increase the discharge rate from the nozzle of the molten mixture of mixture A and mixture B to 13.6 g / min, increase the flow rate of air supplied to the center of the nozzle to 4.8 ml / min, and then melt extrude into Hollow fiber, introduced into a cooling bath at 10°C, allowed to cool and solidify to obtain the first intermediate molded body, except that the draw ratio of the second intermediate molded body was changed to 1.8 times, and the other operations were the same as in Example 1. , to obtain a hollow fiber porous membrane.

Embodiment 3

[0113] In addition to using the main body PVDF and PVDF for modification, they were mixed at a ratio of 85% by weight and 15% by weight, and the Mw was 4.91×10 5 Except for the mixture A, the others were the same as in Example 2 to obtain a hollow fiber porous membrane.

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Abstract

A hollow-fiber porous membrane, comprising a hollow fiber-form porous membrane in a network texture of vinylidene fluoride resin showing a pore size distribution in a direction of its membrane thickness including an outer surface-average pore size P1 as measured by a scanning electron microscope and a membrane layer-average pore size P2 as measured by half-dry method giving a ratio P1 / P2 of at least 2.5. The hollow-fiber porous membrane is excellent in long-term water filtration performance including efficiency of regeneration by air scrubbing. The hollow-fiber porous membrane is produced through a process, wherein a mixture of vinylidene fluoride resin, a plasticizer and a good solvent for vinylidene fluoride resin, is melt-extruded in a hollow-fiber film and cooled and formed into a solidified film within a cooling medium containing at least a certain proportion of a good solvent for vinylidene fluoride resin.

Description

technical field [0001] The present invention relates to a hollow fiber porous membrane made of 1,1-vinylidene fluoride resin (hollow fiber porous membrane), a water filtration method using the same, and a production method thereof. The hollow fiber porous membrane not only has excellent mechanical strength, but also has Furthermore, it is excellent in long-term water treatment performance including regeneration efficiency. 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. When used in water treatment applications, especially in water preparation or sewage treatment applications, hollow fiber porous membranes are often used which tend to increase the membrane area per volume unit of a filtration device. [0003] The hollow fiber porous membrane used in the filtration operation is undoubtedly required to have a ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D71/34B01D65/02B01D69/08C02F1/44D01F6/12
CPCB01D2323/20B01D2325/022B01D2325/24B01D71/34B01D69/02B01D69/08B01D67/0018B01D2325/0233
Inventor 高桥健夫多田靖浩铃木贤一日野雅之谷口慎吾水野斌也
Owner KUREHA KAGAKU KOGYO KK