Highly asymmetric, hydrophilic, microfiltration membranes having large pore

An asymmetric, microporous technology, applied in filtration separation, membrane, membrane technology, etc., can solve problems such as unsuitable for asymmetric membrane applications

Inactive Publication Date: 2000-05-24
PALL CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the membranes prepared according to the Kraus patent are isotropic and thus not suitable for applications in asymmetric membranes

Method used

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  • Highly asymmetric, hydrophilic, microfiltration membranes having large pore
  • Highly asymmetric, hydrophilic, microfiltration membranes having large pore
  • Highly asymmetric, hydrophilic, microfiltration membranes having large pore

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0110] A homogeneous casting solution was prepared using 9.3% polysulfone polymer (Udel 3500), 19% polyethylene glycol (MW200), 4.3% polyvinylpyrrolidone, 1.8% water, and 65.6% N-methylpyrrolidone. The casting solution was stored at room temperature about 25°C. The casting surface was a moving polyethylene coated paper tape with a 24 mil knife slit. After casting, the casting material was exposed to humid air (relative humidity 65-70%) for 6 seconds, and then quenched in a water bath at a temperature of 40 to 45°C.

[0111] After quenching, the membrane was removed, washed with deionized water, and dried in an oven at about 100°C. Afterwards, the membranes were tested for water flow and average flow pore size. Water flow through the membrane was measured at 10 psid in a standard 47mm disc holder, and a Coulter porometer was used to measure the average flow pore size. The membrane is shown in Figure 1 and has the following properties:

[0112] Water flow (ml / min / 9....

Embodiment 2

[0114] A homogeneous casting solution was prepared using 9.3% polysulfone polymer (Udel 3500), 19% polyethylene glycol (MW200), 4.3% polyvinylpyrrolidone, 1.8% water, and 65.6% N-methylpyrrolidone. The casting solution was stored at room temperature about 25°C. The casting surface was a moving polyethylene coated paper tape with a 19 mil knife gap. After casting, the casting material was exposed to humid air (relative humidity 65-70%) for 9 seconds, and then quenched in a water bath at a temperature of 40 to 45°C.

[0115] After quenching, the membrane was removed, washed with deionized water, and dried in an oven at 100°C. Afterwards, the membranes were tested for water flow and average flow pore size. Water flow through the membrane was measured at 10 psid in a standard 47mm disc holder, and a Coulter porometer was used to measure the average flow pore size. The membrane is shown in Figure 2 and has the following properties:

[0116] Water flow (ml / min / 9.5cm 2 ...

Embodiment 3-6

[0118] Effect of Exposure Time and Humidity

[0119] The method of Example 1 was repeated, except that the exposure time and relative humidity were changed according to Table V. The effect of the changes on the prepared membranes is indicated.

[0120] Example

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Abstract

The present invention relates to the field of synthetic polymeric microfiltration membrane materials that are fabricated to separate liquids from solids contained therein. One aspect of the invention relates to a highly asymmetric, hydrophilic microfiltration membrane with high surface porosity. The membrane is rendered hydrophilic through co-casting the sulfone polymer with a hydrophilic polymer, such as polyvinylpyrrolidone. The membranes of the invention are highly useful in testing devices for the quick detection of properties or components contained in liquid samples, such as diagnostic applications, as well as for other filtration applications that demand relatively large pore sizes, thick membranes, high asymmetry, and / or high lateral wicking speeds.

Description

field of invention [0001] The present invention relates to highly asymmetric, hydrophilic microporous filtration membranes. The surface of the membrane has a minimum pore size greater than about 0.1 μm and progressively increases in pore size throughout the secondary structure of the membrane, up to about 100 μm in the coarsely porous surface. Background technique [0002] Asymmetric or anisotropic membranes are well known in the art. For example, U.S. Patent Nos. 4,629,563 and 4,774,039 to Wrasidlo and U.S. Patent Nos. 5,188,734 and 5,171,445 to Zepf, the disclosures of which are incorporated herein, each disclose asymmetric or anisotropic membranes and methods for their preparation. Each of the Wrasidlo and Zepf patents discloses monolithic, highly asymmetric microporous membranes with high flow rates and excellent retention properties. The films are generally prepared by a modified "phase inversion" method, in which a metastable two-phase liquid dispersion of the polyme...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D39/16B01D67/00B01D69/02B01D71/68B01D71/72B32B5/32C08J9/28
CPCB01D2325/022B01D67/0011B01D2323/12B01D71/68B01D69/12B01D67/0013B01D2325/04Y10T428/2975B01D2323/08B01D69/02Y10T428/249979B01D67/0016Y10T428/249961B01D2325/02Y10T436/255B01D2325/36Y10T428/24998Y10T428/24992Y10T428/249989B01D39/16Y10T436/25375B01D2323/02
Inventor 王易帆理查德·A·莫里斯罗伯特·泽普夫
Owner PALL CORP
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