Process for making membranes

Patent metadata

Field	Value
Publication number	US-10906012-B2
Application number	US-201615758641-A
Country	US
Kind code	B2
Filing date	Sep 7, 2016
Priority date	Sep 17, 2015
Publication date	Feb 2, 2021
Grant date	Feb 2, 2021

Abstract

Process for making membranes M comprising the following steps: a) providing a dope solution D comprising at least one polymer P and at least one solvent S, b) adding at least one coagulant C to said dope solution D to coagulate said at least one polymer P from said dope solution D to obtain a membrane M, wherein said at least one solvent S comprises more than 50% by weight of at least one compound according to formula (I) (I), wherein R 1 and R 2 are independently C 1 to C 20 alkyl, R 3 is selected from H or an aliphatic rest, 20 R 4 is selected from H or an aliphatic rest, AO represents at least one alkylene oxide, n is a number from 0 to 100.

First claim

The invention claimed is:

1. A process for making membranes M, comprising:
a) providing a dope solution D comprising at least one polymer P and a solvent S, wherein the at least one polymer P is selected from the group consisting of poly(vinylidene fluoride) (PVDF), polysulfone (PSU), polyphenylenesulfone (PPSU), polyethersulfone (PESU), and mixtures thereof; and
b) adding at least one coagulant C to the dope solution D to coagulate the at least one polymer P from the dope solution D to obtain membrane M,
wherein the solvent S is N,N-dimethyl-2-hydroxypropanoic amide or N,N-diethyl-2-hydroxypropanoic amide.

2. The process according to claim 1 , wherein the at least one coagulant C comprises water or water vapor.

3. The process according to claim 1 , wherein the dope solution D further comprises 0.1 to 10% by weight, based on a weight of the of the dope solution, of additives selected from polyvinylpyrrolidone, and polyalkylene oxides.

4. The process according to claim 1 , wherein after a) and b) the membrane M is subjected to an oxidative treatment.

5. The process according to claim 1 , wherein the membrane M is an ultrafiltration membrane, a microfiltration membrane or a component of a reverse osmosis or forward osmosis membrane.

6. A membrane obtained according to the process according to claim 1 .

7. A membrane element comprising membranes obtained in the process according to claim 1 .

8. A membrane module comprising membranes obtained in the process according to claim 1 .

9. A filtration system comprising the membrane modules according to claim 8 .

10. A filtration system comprising the membrane elements according to claim 7 .

11. The process according to claim 1 , further comprising after a) and b), washing the membrane with water.

Assignees

• Basf Se

Inventors

• Gronwald Oliver
• Weber Martin
• Rittig Frank
• Heijnen Martin
• Urch Henning

Classifications

• B01D61/002

  Forward osmosis or direct osmosis · CPC title

• B01D67/0009

  by phase separation, sol-gel transition, evaporation or solvent quenching · CPC title

• B01D67/00111

  Polymer pretreatment in the casting solutions · CPC title

• B01D69/02 Primary

  characterised by their properties · CPC title

• B01D71/68 Primary

  Polysulfones; Polyethersulfones · CPC title