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1. (WO2019042749) MEMBRANE MANUFACTURING WITH A COSOLVENT IN THE POLYMER DOPE SOLUTION
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Claims

A process for making a nonionic membrane M comprising the following steps:

providing a dope solution D comprising

a polymer P selected from polyphenylenesulfone or mixtures of

polyphenylenesulfone with nonionic polyarylene ethers,

a first solvent selected from aprotic polar solvents, and

a cosolvent selected from C2-C8 alkanediol, C3-C8 alkanetriol, polyethylene glycol, or mixtures thereof; and

preparing the membrane by bringing the dope solution D into contact with a coagulating agent.

The process according to claim 1 wherein the weight ratio of the first solvent to the cosolvent is in the range from 30:1 to 1 :2, preferably from 10:1 to 1 :1 , and in particular from 8:1 to 5:1.

The process according to claim 1 or 2 wherein the dope solution D comprises 1 to 30 wt%, preferably 2 to 20 wt%, and in particular 5 to 15 wt% of the cosolvent.

The process according to any of claims 1 to 3 wherein the dope solution D comprises at least 35 wt%, preferably at least 45 wt%, and in particular at least 55 wt% of the first solvent.

The process according to any of claims 1 to 4 wherein the first solvent is selected from high-boiling ethers, esters, ketones, asymmetrically halogenated hydrocarbons, anisole, dimethylformamide, dimethyl sulfoxide, sulfolane, N-methyl-2-pyrrolidone, N-ethyl-2-pyrro- lidone, or mixtures thereof.

The process according to any of claims 1 to 5 wherein the first solvent is selected from N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, or mixtures thereof.

The process according to any of claims 1 to 6 wherein the cosolvent is selected from C2-C4 alkanediol, C3-C4 alkanetriol, polyethylene glycol with a molar mass of 100 to 1000 g/mol, or mixtures thereof.

8. The process according to any of claims 1 to 7 wherein the cosolvent is selected from 1 ,2- propandiol, 1 ,3-propandiol, glycerin, polyethylene glycol with a molar mass of 300 to 600 g/mol or mixtures thereof.

9. The process according to any of claims 1 to 8 wherein said polymer P is selected from polyphenylenesulfone and mixtures of polyphenylenesulfone with polyethersulfone or polysulfone.

The process according to any of claims 1 to 9 wherein said polymer P is selected from polyphenylenesulfone.

The process according to any of claims 1 to 10 wherein the polymer P comprises at least 60 wt%, preferably at least 80 wt%, and in particular at least 95 wt% of the

polyphenylenesulfone.

12. The process according to any of claims 1 to 1 1 wherein said at least one coagulating agent comprises water.

13. The process according to any of claims 1 to 12 further comprising a step of adding to the dope solution D a solution S which comprises a copolymer C in solvent L, wherein said copolymer C comprises blocks of at least one polyarylene ether A and blocks of polyalkylene oxide PAO, wherein the content of polyalkylene oxide PAO in copolymer C is 30 to 90 % by weight.

14. A nonionic membrane M obtainable in the process according to any of claims 1 to 13.

15. A use of the nonionic membrane M obtainable in the process according to any of claims 1 to 13 for filtering an aqueous liquid through the membrane.