Hollow fiber membrane and method of preparing the same

Patent metadata

Field	Value
Publication number	US-10471395-B2
Application number	US-201715716787-A
Country	US
Kind code	B2
Filing date	Sep 27, 2017
Priority date	Sep 27, 2016
Publication date	Nov 12, 2019
Grant date	Nov 12, 2019

Abstract

A hollow fiber membrane and a method of preparing the same. The hollow fiber membrane has an inner surface and an outer surface, wherein the inner surface has a zebra-stripe pattern in which a dense portion and a porous portion are alternately formed in a longitudinal direction of the hollow fiber membrane.

First claim

What is claimed is:

1. A hollow fiber membrane having an inner surface and an outer surface, wherein the inner surface has a zebra-stripe pattern in which a dense portion and a porous portion are alternately formed in a longitudinal direction of the hollow fiber membrane.

2. The hollow fiber membrane according to claim 1 , wherein the dense portion has no pore having a diameter of about 0.08 μm or more, and the porous portion has about 1 or more pores having a diameter of about 0.1 μm or more per about 5 μm 2 .

3. The hollow fiber membrane according to claim 1 , wherein an apparent area ratio of the porous portion to the dense portion satisfies Equation 1:
about 0.25≤apparent area ratio ( P/D )≤about 2.5

where P denotes an apparent area of the porous portion and D denotes an apparent area of the dense portion.

4. The hollow fiber membrane according to claim 1 , wherein the porous portion has an average pore diameter of about 0.1 μm to about 0.55 μm and the dense portion has an average pore diameter of about 0.001 μm to about 0.05 μm.

5. The hollow fiber membrane according to claim 1 , wherein the hollow fiber membrane has a tensile strength of about 0.6 kgf/fiber or more.

6. The hollow fiber membrane according to claim 1 , wherein the hollow fiber membrane has a water permeability (flux) of about 430 LMH to about 3,000 LMH.

7. The hollow fiber membrane according to claim 1 , wherein the hollow fiber membrane has a membrane index of about 600 or more, as represented by Equation 2:
Membrane index=tensile strength (kgf/fiber)×water permeability (LMH).

8. The hollow fiber membrane according to claim 1 , wherein the hollow fiber membrane is a single membrane.

9. A method of preparing a hollow fiber membrane, comprising:
preparing a spinning solution using a composition comprising a vinylidene fluoride polymer resin and a first plasticizer having a viscosity of about 300 cP to about 4,000 cP;
forming a pre-hollow fiber membrane by bringing the spinning solution into contact with a second plasticizer having a viscosity of about 300 cP to about 4,000 cP in a dual-concentric nozzle, and spraying and coagulating the spinning solution;
extracting the first and second plasticizers from the pre-hollow fiber membrane;
heat treating the pre-hollow fiber membrane; and
stretching the pre-hollow fiber membrane subjected to heat treatment.

10. The method of preparing a hollow fiber membrane according to claim 9 , wherein the first plasticizer and the second plasticizer are the same kind of plasticizer.

11. The method of preparing a hollow fiber membrane according to claim 9 , wherein heat treatment of the pre-hollow fiber membrane is performed at about 80° C. to about 150° C. for about 30 to 200 minutes.

12. The method of preparing a hollow fiber membrane according to claim 9 , wherein stretching of the pre-hollow fiber membrane subjected to heat treatment is performed to an elongation of about 30% to about 200% at about 10° C. to about 50° C.

13. The method of preparing a hollow fiber membrane according to claim 9 , wherein the composition comprises about 10 wt % to about 60 wt % of the vinylidene fluoride polymer resin and about 40 wt % to about 90 wt % of the first plasticizer.

14. The method of preparing a hollow fiber membrane according to claim 9 , wherein the vinylidene fluoride polymer resin comprises at least one of a vinylidene fluoride homopolymer and a vinylidene fluoride copolymer.

15. The method of preparing a hollow fiber membrane according to claim 9 , wherein the first plasticizer or the second plasticizer comprises at least one of a polyester plasticizer, a phthalic acid plasticizer, an adipic acid plasticizer, and a trimellitic acid plasticizer.

16. The method of preparing a hollow fiber membrane according to claim 9 , wherein the composition further comprises a good solvent.

Assignees

• Lotte Chemical Corp

Inventors

• Im Dong Jun
• Park Bum Jin
• Seo Chang Min

Classifications

• B01D69/081 Primary

  characterised by the fibre diameter · CPC title

• B01D69/08

  Hollow fibre membranes (manufacture of hollow fibres D01D5/24, D01F1/08) · CPC title

• C02F1/444

  by ultrafiltration or microfiltration · CPC title

• B01D67/0002

  Organic membrane manufacture · CPC title

• B01D2325/08

  Patterned membranes · CPC title