Filtration membrane with improved hydrophilicity

A process for the preparation of a membrane (M) containing a sulfonated polyarylenesulfone polymer (sP) and at least one further polymer (fP) comprising the steps

• i) converting a reaction mixture (RG) comprising
• an aromatic dihalogensulfone component (component (A)) comprising
• at least one sulfonated aromatic dihalogensulfone (component (A1)), and at least one non sulfonated aromatic dihalogensulfone (component (A2)),
• at least one aromatic dihydroxy compound (component (B)),
• at least on carbonate compound (component (C)), and
• at least one aprotic polar solvent (component (D)),
• to obtain a product mixture (PG) comprising the sulfonated polyarylenesulfone polymer (sP), the at least one aprotic polar solvent and at least one inorganic halide compound,
• ii) separating the at least one inorganic halide compound from the product mixture (PG) to obtain a first solution (S1) comprising the sulfonated polyarylenesulfone polymer (sP) and the at least one aprotic polar solvent,
• iii) mixing at least one further polymer (fP) with the first solution (S1) to obtain a second solution (S2),
• iv) separating the at least one aprotic polar solvent from the second solution (S2) to obtain the membrane (M) containing the sulfonated polyarylenesulfone polymer (sP) and the at least one further polymer (fP),
• wherein in step iii) additionally at least one pore forming agent (pA) is mixed with the first solution (S1) to obtain the second solution (S2) and wherein the at least one further polymer (fP) is at least one polyarylenesulfone polymer which may be sulfonated or unsulfonated and wherein the sulfonated polyarylenesulfone polymer (sP) and the at least one further polymer (fP) are different from each other, wherein
• component (A1) comprises at least one compound selected from the group consisting of 4,4′-dichlorodiphenylsulfone-3,3′-disulfonic acid, 4,4′-dichlorodiphenylsulfone-3,3′-disulfonic acid disodium salt, 4,4′-dichlorodiphenylsulfone-3,3′-disulfonic acid dipotassium salt, 4,4′-difluorodiphenylsulfone-3,3′-disulfonic acid, 4,4′-difluorodiphenylsulfone-3,3′-disulfonic acid disodium salt and 4,4′-difluorodiphenylsulfone-3,3′-disulfonic acid dipotassium salt, and
• component (A2) comprises not less than 80 wt % of at least one aromatic dihalogensulfone selected from the group consisting of 4,4′-dichlorodiphenylsulfone and 4,4′-difluorodiphenylsulfone, based on the overall weight of component (A2) in reaction mixture (RG), and
• component (B) is selected from the group consisting of 4,4′-dihydroxybiphenyl, 4,4′-dihydroxydiphenylsulfone, bisphenol A (2,2-bis(4-hydroxyphenyl) propane), 4,4′-dihydroxybenzophenone, hydroquinone and hydrochinone derivatives, and
• in step i) a reaction mixture (RG) is converted comprising
• X mol of an aromatic dihalogensulfone component (component A)) comprising, based on the total molar amount of the aromatic dihalogensulfone component (component A)) in the reaction mixture (RG),
• X1 mol.-% of at least one sulfonated aromatic dihalogensulfone (component (A1)), and
• X2 mol.-% of at least one non sulfonated aromatic dihalogensulfone (component (A2)), wherein
• X1 is in the range of 2 to 70 and
• X2 is in the range of 30 to 98,
• Y mol of at least one aromatic dihydroxy compound (component (B))
• Z mol of at least one carbonate compound (component (C)),
• wherein
• the ratio of X to Y is in the range of 0.95 to 1.08,
• and wherein
• Z is in the range of P to Q,
• wherein P is calculated according to the following equation:
• P
• =
• Y
• *
• (
• 1.05
• +
• X
• 1
• /
• 100
• *
• 1.05
• )
• ,
• and wherein Q is calculated according to the following equation:
• Q
• =
• Y
• *
• (
• 1.05
• +
• X
• 1
• /
• 100
• *
• 1.4
• )
• .