Separation membrane, method of producing the same and separation membrane module using the separation membrane

Patent metadata

Field	Value
Publication number	US-9561478-B2
Application number	US-201314077850-A
Country	US
Kind code	B2
Filing date	Nov 12, 2013
Priority date	Mar 31, 2008
Publication date	Feb 7, 2017
Grant date	Feb 7, 2017

Abstract

A separation membrane includes a membrane comprising a polymer, characterized in that a functional layer is formed on the surface in one side of the membrane, the peak area percentage of carbon derived from ester group measured by the electron spectroscopy for chemical analysis (ESCA) on the surface of the preceding functional layer is 0.1% (by atomic number) or more but not more than 10 (% by atomic number), and the peak area percentage of carbon derived from ester group measured by the electron spectroscopy for chemical analysis (ESCA) on the surface opposite to the functional layer is not more than 10 (% by atomic number). A separation membrane module suffering from little sticking of organic matters, proteins, platelets and so on is provided with the separation membrane as a built-in membrane.

First claim

What is claimed:

1. A separation membrane, comprising a membrane comprising a polymer, wherein
the membrane, has a functional layer in one side surface, the functional layer has a surface showing an ester carbon peak area percentage of 0.1 (at. %) to 10 (at. %) as measured by X-ray electron spectroscopy (ESCA),
the membrane has an opposite surface from the functional layer,
the opposite surface shows an ester carbon peak area percentage of less than 10 (at. %) as measured by X-ray electron spectroscopy (ESCA), a surface of a functional layer has an ester carbon content 10% or more higher than that of an opposite surface from the functional layer,
wherein the separation membrane contains a water-soluble polymer which is polyvinylpyrrolidone, polyethylene glycol, or polyvinyl alcohol, and

wherein the separation membrane contains an insoluble component which remains after the polymer of the separation membrane is dissolved in a good solvent, wherein said insoluble component has a water content of 95% or more.

2. The separation membrane according to claim 1 , wherein the ester in the surface of the functional layer is derived from an ester group-containing polymer.

3. The separation membrane according to claim 2 , wherein the ester group-containing polymer comprises at least one selected from a vinyl carboxylate ester unit, an acrylate ester unit and a methacrylate ester unit.

4. The separation membrane according to claim 2 , wherein the ester group-containing polymer is polyvinyl acetate or a copolymer of vinyl acetate and vinylpyrrolidone.

5. The separation membrane according to claim 1 , wherein the membrane comprises a hydrophobic polymer.

6. The separation membrane according to claim 5 , wherein the hydrophobic polymer is a polysulfone-based polymer.

7. The separation membrane according to claim 1 , wherein the membrane is a hollow fiber membrane.

8. The separation membrane according to claim 1 , wherein the membrane is for use in blood purification.

9. A separation membrane module, comprising the separation membrane according to claim 1 as a built-in element.

10. A method of producing a separation membrane comprising a hydrophobic polymer, wherein a surface of a functional layer has an ester carbon content 10% or more higher than that of an opposite surface from the functional layer, wherein the separation membrane contains a water-soluble polymer which is polyvinylpyrrolidone, polyethylene glycol, or polyvinyl alcohol, wherein the separation membrane contains an insoluble component, which remains after the polymer of the separation membrane is dissolved in a good solvent, wherein said insoluble content has a water content of 95% or more, comprising;
forming a coating of an ester group-containing polymer, wherein the ester group-containing polymer has an adsorption equilibrium constant of 330 pg/(mm 2 ·ppm) to 1,100 pg/(mm 2 ·ppm) on the hydrophobic polymer, and
a solution of the ester group-containing polymer is brought into contact with the hydrophobic polymer under a pressure difference generated between the inside and the outside of the separation membrane.

11. The method according to claim 10 , wherein the step of forming the coating comprises bringing the solution of the ester group-containing polymer into contact with the separation membrane and performing irradiation with radiation and/or heat treatment.

Assignees

• Toray Industries

Inventors

• Ueno Yoshiyuki
• Fujita Masaki
• Sugaya Hiroyuki

Classifications

• B01D2325/38

  Hydrophobic membranes · CPC title

• B01D2323/02

  Hydrophilization · CPC title

• B01D2323/385

  involving radiation · CPC title

• B01D71/68

  Polysulfones; Polyethersulfones · CPC title

• B01D69/02

  characterised by their properties · CPC title