Porous membrane

Patent metadata

Field	Value
Publication number	US-11033864-B2
Application number	US-201615574305-A
Country	US
Kind code	B2
Filing date	May 27, 2016
Priority date	May 27, 2015
Publication date	Jun 15, 2021
Grant date	Jun 15, 2021

Abstract

A porous membrane comprising a membrane-forming polymer (A) and a polymer (B) containing a methyl methacrylate unit and a hydroxyl group-containing (meth)acrylate (b1) unit. A flux of pure water to permeate the porous membrane is preferably 10 (m 3 /m 2 /MPa/h) or more and less than 200 (m 3 /m 2 /MPa/h). The contact angle of the bulk of the membrane-forming polymer (A) is preferably 60° or more. The membrane-forming polymer (A) is preferably a fluorine-containing polymer. The polymer (B) is preferably a random copolymer.

First claim

The invention claimed is:

1. A porous membrane, comprising:
a membrane-forming polymer (A); and
a polymer (B) comprising a methyl methacrylate unit and from 20 to 60% by mass of a hydroxyl group-containing (meth)acrylate (b1) unit based on the total mass of the polymer (B),
wherein the polymer (B) is a random copolymer.

2. The membrane of claim 1 , wherein a flux of pure water to permeate the porous membrane is 10 (m 3 /m 2 /MPa/h) or more and less than 200 (m 3 /m 2 /MPa/h).

3. The membrane of claim 1 , wherein a contact angle of the bulk of the membrane-forming polymer (A) is 60° or more.

4. The membrane of claim 1 , wherein the membrane-forming polymer (A) is a fluorine-containing polymer.

5. The membrane of claim 1 , wherein the hydroxyl group-containing (meth)acrylate (b1) unit comprises 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, polyethylene glycol (meth)acrylate, and/or polypropylene glycol (meth)acrylate.

6. The membrane of claim 1 , wherein the polymer (B) further comprises a monomer (b2) unit.

7. The membrane of claim 6 , wherein the other monomer (b2) unit is a (meth)acrylate unit comprising nitrogen.

8. The membrane of claim 7 , wherein the (meth)acrylate unit comprising nitrogen is either a unit of dimethylaminoethyl methacrylate or a quaternary salt of dimethylaminoethyl methacrylate.

9. The membrane of claim 6 , wherein the methyl methacrylate unit, the hydroxyl group-containing (meth)acrylate (b1) unit, and the other monomer (b2) unit in the polymer (B) are all methacrylate units.

10. The membrane of claim 6 , wherein the methyl methacrylate unit is from 20 to 60% by mass, and the monomer (b2) unit is from 1 to 60% by mass in the polymer (B).

11. The membrane of claim 6 , wherein a molecular weight of the monomer (b2) constituting the polymer (B) is 300 or less.

12. The membrane of claim 1 , wherein a proportion of the polymer (B) with respect to a sum of the membrane-forming polymer (A) and the polymer (B) in the porous membrane is from 0.1 to 40% by mass.

13. The membrane of claim 1 , wherein a contact angle of an outer surface of the porous membrane to pure water is from 1 to 70°.

14. The membrane of claim 1 , wherein an average pore diameter of a surface of the porous membrane is 300 nm or less.

15. The membrane of claim 14 , wherein an average pore diameter of a surface of the porous membrane is 150 nm or less.

16. The membrane of claim 1 , wherein a shape of the porous membrane is a hollow fiber shape.

17. A water treatment apparatus, comprising the membrane of claim 16 .

18. A method of manufacturing a porous membrane, the method comprising:
coagulating a membrane-forming stock solution comprising a membrane-forming polymer (A), a polymer (B) comprising a methyl methacrylate unit and from 20 to 60% by mass of a hydroxyl group-containing (meth)acrylate (b1) unit based on the total mass of the polymer (B), and a solvent,
wherein the polymer (B) is a random copolymer.

19. The method of claim 18 , wherein the polymer (B) does not comprise a (meth)acrylic acid unit.

20. The membrane of claim 1 , wherein the polymer (B) does not comprise a (meth)acrylic acid unit.

21. The membrane of claim 1 , wherein a flux of pure water to permeate the porous membrane is 10 (m 3 /m 2 /MPa/h) or more and less than 200 (m 3 /m 2 /MPa/h),
wherein a contact angle of the bulk of the membrane-forming polymer (A) is 60° or more, and
wherein an average pore diameter of a surface of the porous membrane is 300 nm or less.

22. The membrane of claim 2 , wherein the polymer (B) further comprises a monomer (b2) unit, and
wherein the methyl methacrylate unit is from 20 to 60% by mass, and the monomer (b2) unit is from 1 to 60% by mass in the polymer (B).

23. The membrane of claim 22 , wherein the other monomer (b2) unit is a (meth)acrylate unit comprising nitrogen.

24. The membrane of claim 1 , wherein the polymer (B) comprises more than 95% of methyl methacrylate, the hydroxyl group-containing (meth)acrylate (b1), and optionally a further monomer (b2),
wherein the further monomer (b2) is ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, isoamyl methacrylate, hexyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, glycidyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, methoxyethyl methacrylate, ethoxyethyl (meth)acrylate, n-butoxyethyl (meth)acrylate, isobutoxyethyl (meth)acrylate, t-butoxyethyl (meth)acrylate, phenoxyethyl (meth)acrylate, nonylphenoxyethyl(meth) acrylate, 3-methoxybutyl (meth)acrylate, methoxypolyethylene glycol methacrylate with a 2 ethylene glycol chain, methoxypolyethylene glycol methacrylate with a 4 ethylene glycol chain, dimethylaminoethyl methacrylate, chloride salt of dimethylaminoethyl methyl methacrylate, methacrylic acid dimethyl amino ethyl methyl sulfate, 3-(methacrylamido)propyltrimethyl ammonium chloride, 3-(methacrylamido)propyltrimethylammonium methyl sulfate, and/or a quaternary salt of dimethylaminoethyl methacrylate.

Assignees

• Mitsubishi Chem Corp

Inventors

• Hikita Shingo
• Teramachi Masashi
• SHINODA Ami
• SUENAGA Naotaka
• Fukuta Hiroki

Classifications

• B01D71/40 Primary

  Polymers of unsaturated acids or derivatives thereof, e.g. salts, amides, imides, nitriles, anhydrides, esters · CPC title

• B01D2325/0283

  Pore size · CPC title

• B01D67/00111

  Polymer pretreatment in the casting solutions · CPC title

• B01D67/0016

  Coagulation · CPC title

• B01D67/0013

  Casting processes · CPC title