Separation membrane

Patent metadata

Field	Value
Publication number	US-2017296984-A1
Application number	US-201515515761-A
Country	US
Kind code	A1
Filing date	Sep 30, 2015
Priority date	Sep 30, 2014
Publication date	Oct 19, 2017
Grant date	—

Abstract

The present invention provides a separation membrane having excellent separation performance and permeation performance, having high membrane strength, and mainly including a cellulose-based resin. The present invention relates to a separation membrane containing a cellulose ester and having a tensile elasticity of 1,500 to 6,500 MPa.

First claim

1 . A separation membrane containing a cellulose ester and having a tensile elasticity of 1,500 to 6,500 MPa and a salt rejection of 90.0% or more.

2 . The separation membrane according to claim 1 , having a shape of a hollow fiber and having a tensile elasticity in a lengthwise direction of 1,500 to 6,500 MPa.

3 . The separation membrane according to claim 2 , wherein the hollow fiber has an outer diameter of 20 to 200 μm.

4 . The separation membrane according to claim 1 , having a degree of orientation of 1.05 to 2.50 in a lengthwise direction of the separation membrane.

5 . The separation membrane according to claim 1 , having a crystal melting heat amount (ΔHm) of 4 to 20 J/g in a temperature rise measurement with a differential scanning calorimeter (DSC).

6 . The separation membrane according to claim 1 , having a positron annihilation life of 2.2 to 3.0 ns.

7 . The separation membrane according to claim 1 , wherein the cellulose ester is at least one of cellulose acetate propionate and cellulose acetate butyrate.

8 . The separation membrane according to claim 1 , containing a polyalkylene glycol having a number average molecular weight (Mn) of 2,000 to 1,000,000.

9 . The separation membrane according to claim 1 , which is any one selected from a nanofiltration membrane, a reverse osmosis membrane and a forward osmosis membrane.

10 . A method for producing a hollow fiber, the method comprising: discharging from a spinneret a polymer obtained by kneading at least 50% to 95% by weight of a cellulose ester and 5% to 50% by weight of a polyalkylene glycol, followed by winding at a draft ratio of 200 or more while cooling with cooling air.

11 . A method for producing a hollow fiber membrane, the method comprising: eluting a polyalkylene glycol from a hollow fiber containing a cellulose ester at a ratio of 50% to 95% by weight and the polyalkylene glycol at a ratio of 5% to 50% by weight.

12 . A hollow fiber membrane module comprising:
a case; and the separation membrane according to claim 2 , which is filled in the case.

13 . A water production method comprising: a step of feeding mixed liquid containing water to the separation membrane according to claim 1 at a pressure of 0.3 to 6.0 MPa.

Assignees

• Toray Industries

Inventors

• Yamamura Gohei
• Takada Koichi
• Hiranabe Ryuichiro
• Tomioka Hiroki

Classifications

• C02F1/44 Primary

  by dialysis, osmosis or reverse osmosis {(general membrane separation processes B01D61/00, membrane modules B01D63/00, electrodialysis C02F1/4693, combination of membrane modules and bioreactors C02F3/1268)} · CPC title

• B01D69/08

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

• B01D71/18 Primary

  Mixed esters, e.g. cellulose acetate-butyrate · CPC title

• C02F2103/08

  Seawater, e.g. for desalination · CPC title

• B01D2325/24

  Mechanical properties, e.g. strength · CPC title