Filtration membrane with improved hydrophilicity

Abstract

The present invention relates to a process for preparing a membrane (M) containing a sulfonated polyarylene sulfone polymer (sP) and at least one further polymer (fP), the membrane (M) obtained by the process according to the invention, a filtration (nanofiltration, ultrafiltration or microfiltration) system comprising the membrane (M) and the use of the membrane (M) in a filtration process.

Description

[0001] manual

[0002] The present invention relates to a process for preparing a membrane (M) containing a sulfonated polyarylene sulfone polymer (sP) and at least one further polymer (fP), the membrane (M) obtained by the process of the invention, a filtration (nanofiltration, ultrafiltration or microfiltration) system comprising the membrane (M) and the use of the membrane (M) in a filtration process.

[0003] Polyarylene sulfone polymers are high-performance thermoplastics because they have high heat resistance, good mechanical properties and inherent flame retardancy (EM Koch, H.-M. Walter, Kunststoffe 80 (1990) 1146; E. Kunststoffe 80, (1990) 1149, N. Inchaurondo-Nehm, Kunststoffe 98, (2008) 190). They are highly biocompatible and are therefore used as materials for dialysis membranes (NA Hoenich, KP Katapodis, Biomaterials 23 (2002) 3853) and ultrafiltration (UF) membranes. Ultrafiltration membranes (UF) are believed to have an active filter layer with a molecular weight cutoff of 10 kDa to 100 kDa corresponding to a pore size of 10 nm to 30 nm to effectively remove yeast, bacteria, viruses and macromolecules from water. Since the increased hydrophilicity of the membrane is believed to prevent performance loss by fouling effects (D. Rana et al. "Surface modifications for antifouling membranes", Chemical Reviews, 2010, 110, 2448), sulfonated poly (arylene sulfone) polymers are also considered for membrane applications.

[0004] In addition to being used as engineering plastics, polyarylene sulfone polymers are also used as membrane materials for water treatment.

[0005] The polyarylene sulfone polymers can be formed, inter alia, via the hydroxide process, in which a salt is first formed from a dihydroxy component and a hydroxide, or via the carbonate process.

[0006] General information on the formation of polyarylene sulfone polymers by the hydroxide process is found, inter alia, in RN Johnson et al., J. Polym. Sci. A-1 5 (1967) 2375, while the carbonate process is described in JEMcGrath et al., Polymer 25 (1984) 1827.

[0007] The formation of polyarylene sulfone polymers from aromatic dihalogen compounds and aromatic bisphenols or their salts in an aprotic solvent in the presence of one or more alkali metal or ammonium carbonates or hydrogencarbonates is known to those skilled in the art and is described, for example, in EP-A 297 363 and EP-A 135 130.

[0008] WO 2019 / 016082 A1 discloses a method for preparing a sulfonated polyarylene ether sulfone polymer (sP) by converting a reaction mixture (RG) comprising at least one non-sulfonated aromatic dihalogen sulfone, at least one sulfonated aromatic dihalogen sulfone, at least one aromatic dihydroxy component comprising trimethylhydroquinone, at least one carbonate component and at least one aprotic polar solvent, wherein the sulfonated polyarylene ether sulfone polymer (sP) can be used in a membrane (M).

[0009] WO 2017 / 148850 A1 discloses a method for producing a membrane (M) comprising an organic polymer (PIM) having intrinsic microporosity and a sulfonated polyarylene sulfone polymer (sP).

[0010] WO 2019 / 016078 A1 discloses a method for preparing a polyaryl ether sulfone-polyalkylene oxide block copolymer (PPC), the method comprising the step I) converting a reaction mixture (RG), the reaction mixture comprising as components (A1) at least one aromatic dihalogen sulfone, (B1) at least one aromatic dihydroxy component comprising trimethylhydroquinone, (B2) at least one polyalkylene oxide, (C) at least one carbonate component, and (D) at least one aprotic polar solvent, wherein the polyaryl ether sulfone-polyalkylene oxide block copolymer (PPC) can be used in a membrane.

[0011] High performance thermoplastics such as polyarylene sulfone polymers are formed by polycondensation reactions, which are typically carried out in polar aprotic solvents such as DMF (dimethylformamide), DMAc (dimethylacetamide), sulfolane, DMSO (dimethylsulfoxide), and NMP (N-methyl-pyrrolidone) at high reaction temperatures.

[0012] Sulfonated polyarylene sulfone polymers have been known for decades. Although direct sulfonation of polyarylene sulfone polymers causes side reactions and allows only limited control over the degree of sulfonation, the use of disulfonated aromatic dihalogen sulfones (such as sulfonated dichlorodiphenyl sulfone (sDCDPS)) as comonomers allows the synthesis of well-defined sulfonated polyarylene sulfone polymers.

[0013] Although sulfonated poly(arylene sulfone) polymers show several interesting properties, it has not yet been possible to produce nanofiltration membranes from poly(arylene sulfone) polymers having both a low molecular weight cut-off and a high water permeability.

[0014] It is therefore an object of the present invention to provide a process for preparing a membrane (M) containing a sulfonated polyarylene sulfone polymer (sP) and at least one further polymer (fP) which does not retain the disadvantages of the prior art or only retains the disadvantages in a reduced form. The process should be easy to implement. The membrane (M) should be suitable for dialysis and ultrafiltration.

[0015] This object is achieved by a process for preparing a membrane (M) containing a sulfonated polyarylene sulfone polymer (sP) and at least one further polymer (fP), the process comprising the following steps

[0016] i) Conversion reaction mixture (R G ), the reaction mixture comprising:

[0017] An aromatic dihalogen sulfone component (component (A)), the aromatic dihalogen sulfone component comprising

[0018] at least one sulfonated aromatic dihalogen sulfone (component (A1)) and at least one non-sulfonated aromatic dihalogen sulfone (component (A2)),

[0019] at least one aromatic dihydroxy compound (component (B)),

[0020] at least one carbonate compound (component (C)), and

[0021] at least one aprotic polar solvent (component (D)),

[0022] To obtain a product mixture (P) comprising the sulfonated polyarylene sulfone polymer (sP), the at least one aprotic polar solvent and the at least one inorganic halide compound G ),

[0023] ii) from the product mixture (P G ) to obtain a first solution (S1) comprising the sulfonated polyarylene sulfone polymer (sP) and the at least one aprotic polar solvent,

[0024] iii) mixing at least one further polymer (fP) with said first solution (S1) to obtain a second solution (S2),

[0025] iv) separating the at least one aprotic polar solvent from the second solution (S2) to obtain a membrane (M) containing the sulfonated polyarylene sulfone polymer (sP) and the at least one further polymer (fP).

[0026] This object is further achieved by a method for preparing a membrane (M) containing a sulfonated polyarylene sulfone polymer (sP) and at least one further polymer (fP), the method comprising the following steps

[0027] i) converting a reaction mixture (RG), said reaction mixture comprising:

[0028] An aromatic dihalogen sulfone component (component (A)), the aromatic dihalogen sulfone component comprising

[0029] at least one sulfonated aromatic dihalogen sulfone (component (A1)), and

[0030] at least one non-sulfonated aromatic dihalogen sulfone (component (A2)),

[0031] at least one aromatic dihydroxy compound (component (B)),

[0032] at least one carbonate compound (component (C)), and

[0033] at least one aprotic polar solvent (component (D)),

[0034] to obtain a product mixture (PG) comprising a sulfonated polyarylene sulfone polymer (sP), at least one aprotic polar solvent and at least one inorganic halide compound,

[0035] ii) separating at least one inorganic halide compound from the product mixture (PG) to obtain a first solution (S1) comprising a sulfonated polyarylene sulfone polymer (sP) and at least one aprotic polar solvent,

[0036] iii) mixing at least one further polymer (fP) with said first solution (S1) to obtain a second solution (S2),

[0037] iv) separating said at least one aprotic polar solvent from said second solution (S2) to obtain said membrane (M) containing said sulfonated polyarylene sulfone polymer (sP) and said at least one further polymer (fP),

[0038] wherein in step iii), additionally at least one pore former (pA) is mixed with the first solution (S1) to obtain the second solution (S2), and wherein the at least one additional polymer (fP) is at least one polyarylene sulfone polymer which may be sulfonated or non-sulfonated, and wherein the sulfonated polyarylene sulfone polymer (sP) and the at least one additional polymer (fP) are different from each other.

[0039] It has surprisingly been found that by the process according to the invention a membrane (M) is obtained which shows improved hydrophilicity, improved pure water permeability (PWP) and improved molecular weight cut-off (MWCO). By the process according to the invention, the preparation time of a membrane (M) containing a sulfonated polyarylene sulfone polymer (sP) can be significantly reduced. The condensation according to step i) produces a polymer suspension containing a sulfonated polyarylene sulfone polymer (sP) and an inorganic halide salt. After separation of the salt, in the prior art, precipitation is usually carried out in isopropanol to separate the sulfonated polyarylene sulfone polymer (sP), which results in the need to reprocess or dispose of large amounts of solvent mixture.

[0040] Furthermore, part of the product is not completely precipitated and can cause clogging of the filter during the subsequent separation. In addition, the sulfonated copolymer must be dissolved again in order to produce the membrane (M). The process according to the invention prevents the production of large amounts of solvent mixtures and avoids separation prior to membrane preparation.

[0041] The present invention will be described in more detail below.

[0042] method

[0043] The process according to the invention for preparing a membrane (M) comprising a sulfonated polyarylene sulfone polymer (sP) and at least one further polymer (fP) comprises steps i), ii), iii) and iv).

[0044] In the context of the present invention, the term "membrane (M)" means a semi-permeable structure capable of separating two fluids or separating molecular and / or ionic components or particles from a liquid. Thus, the membrane acts as a selective barrier, allowing some particles, substances or chemicals to pass through while retaining other particles, substances or chemicals. The membrane (M) can have various geometric shapes, such as flat sheets, spirally wound, pillow blocks, tubular, single-hole hollow fibers or porous hollow fibers.

[0045] The membrane (M) can be used as a nanofiltration membrane.

[0046] Therefore, another object of the present invention is also the use of the membrane (M) as a nanofiltration membrane.

[0047] Step i)

[0048] In step i) according to the present invention, a reaction mixture (R) comprising an aromatic dihalogen sulfone component, at least one aromatic dihydroxy compound, at least one carbonate compound and at least one aprotic polar solvent is converted. G ) to obtain a product mixture (P) comprising a sulfonated polyarylene sulfone polymer (sP), at least one aprotic polar solvent and at least one inorganic halide compound G ).

[0049] The aromatic dihalogen sulfone component is also referred to as component (A). The terms "aromatic dihalogen sulfone component" and "component (A)" in the present invention are used synonymously and thus have the same meaning.

[0050] The at least one aromatic dihydroxy compound is also referred to as component (B). The terms "at least one aromatic dihydroxy compound" and "component (B)" in the present invention are used synonymously and thus have the same meaning.

[0051] The at least one carbonate compound is also referred to as component (C). The terms "at least one carbonate compound" and "component (C)" in the present invention are used synonymously and therefore have the same meaning.

[0052] The at least one aprotic polar solvent is also referred to as component (D). The terms "at least one aprotic polar solvent" and "component (D)" in the present invention are used synonymously and therefore have the same meaning.

[0053] Reaction mixture (R G ) is provided in step i) for forming a product mixture (P G ) in a mixture of sulfonated polyarylene sulfone polymer (sP). G ) refers to the mixture present before the conversion, ie the polycondensation, according to step i).

[0054] By polycondensation of components (A) and (B), polycondensation occurs to convert the reaction mixture (R G ) into a production mixture (P) comprising a sulfonated polyarylene sulfone polymer (sP) G ).

[0055] In step i), component (A) and component (B) enter into a polycondensation reaction. Component (C) acts as a base to deprotonate the hydroxyl groups of component (B). Component (D) serves as a solvent.

[0056] The product mixture (P) obtained after the polycondensation according to step i) G ) comprises a sulfonated polyarylene sulfone polymer (sP). The product mixture (P G ) further comprises the at least one inorganic halide compound and the at least one aprotic polar solvent (component (D)). G ). During the conversion, component (C) reacts with component (B) to deprotonate component (B). Then, the deprotonated component (B) reacts with component (A) to form at least one inorganic halide compound. This process is known to those skilled in the art.

[0057] Reaction mixture (R G ) are preferably reacted simultaneously. The components can be mixed in an upstream step and then reacted. It is also possible to feed the components into a reactor, where they are mixed and then reacted.

[0058] In step i) of the process according to the invention, the reaction mixture (R G ) are preferably reacted simultaneously. The reaction is preferably carried out in one stage. This means that the deprotonation of component (B) and the condensation reaction between components (A) and (B) are preferably carried out in a single reaction stage without isolating intermediate products, such as the deprotonated material of component (B).

[0059] Furthermore, it is preferred that the reaction mixture (R) provided in step i) G ) does not include toluene or monochlorobenzene. It is particularly preferred that the reaction mixture (R G ) does not contain any substances that form azeotropes with water. The same preferably applies to the product mixture (P G ).

[0060] The ratio of component (A) and component (B) in step i) results in principle from the stoichiometry of the polycondensation reaction which is carried out theoretically with elimination of hydrogen halide, preferably hydrogen chloride, and is established in a known manner by the person skilled in the art.

[0061] Preferably, in step i), the ratio of halogen end groups derived from component (A) to phenolic end groups derived from component (B) is adjusted by controlled establishment of an excess of component (A) relative to component (B) as starting compound.

[0062] More preferably, in step i), the molar ratio of component (A) to component (B) is from 0.95 to 1.08, especially from 0.98 to 1.06, most preferably from 0.985 to 1.05.

[0063] Preferably, the conversion in the polycondensation reaction in step i) is at least 0.9.

[0064] The polycondensation reaction in step i) is usually carried out at a temperature in the range of 80° C. to 250° C., preferably in the range of 100° C. to 220° C. The upper limit of the temperature is preferably determined by the boiling point of the at least one aprotic polar solvent (component (D)) at standard pressure (1013.25 mbar). The reaction is usually carried out at standard pressure. The reaction is preferably carried out within a time interval in the range of 0.5 h to 14 h, in particular 1 h to 12 h.

[0065] In a preferred embodiment, in step i), the reaction mixture (R G) conversion, the reaction mixture comprising

[0066] X mol of an aromatic dihalogen sulfone component (component A), the aromatic dihalogen sulfone component comprising: G ),

[0067] X 1 mol.-% of at least one sulfonated aromatic dihalogen sulfone (component (A1)), and

[0068] X 2 mol.-% of at least one non-sulfonated aromatic dihalogen sulfone (component (A2)), wherein

[0069] X 1 In the range of 2 to 70, and

[0070] X 2 In the range of 30 to 98,

[0071] Y mol of at least one aromatic dihydroxy compound (component (B)),

[0072] Z mol of at least one carbonate compound (component (C)),

[0073] in

[0074] The ratio of X to Y is in the range of 0.95 to 1.08,

[0075] And among them

[0076] Z is in the range of P to Q,

[0077] Where P is calculated according to the following formula:

[0078] P=Y*(1.05+X 1 / 100*1.05),

[0079] And where Q is calculated according to the following formula:

[0080] Q=Y*(1.05+X 1 / 100*1.4).

[0081] In a preferred embodiment, no G ) isolating the sulfonated polyarylene sulfone polymer (sP) obtained in step i).

[0082] In one embodiment, no further process steps are carried out between step i) and step ii). In a further preferred embodiment, before carrying out step ii), the product mixture (PG ) in which the sulfonated polyarylene sulfone polymer (sP) remains in dissolved form.

[0083] The components used in step i) are described in more detail below.

[0084] Component (A)

[0085] Component (A), which is also referred to as the aromatic dihalogen sulfone component, comprises at least one sulfonated aromatic dihalogen sulfone and at least one non-sulfonated aromatic dihalogen sulfone.

[0086] The at least one sulfonated aromatic dihalogen sulfone is also referred to as component (A1). The terms "at least one sulfonated aromatic dihalogen sulfone" and "component (A1)" in the present invention are used synonymously and therefore have the same meaning.

[0087] The at least one non-sulfonated aromatic dihalogen sulfone is also referred to as component (A2). The terms "at least one non-sulfonated aromatic dihalogen sulfone" and "component (A2)" in the present invention are used synonymously and therefore have the same meaning.

[0088] Reference herein to "at least one sulfonated aromatic dihalogen sulfone" is intended to mean exactly one sulfonated aromatic dihalogen sulfone as well as mixtures of two or more sulfonated aromatic dihalogen sulfones. Preferably exactly one sulfonated aromatic dihalogen sulfone is used.

[0089] Reference herein to "at least one non-sulfonated aromatic dihalogen sulfone" is intended to mean exactly one non-sulfonated aromatic dihalogen sulfone as well as mixtures of two or more non-sulfonated aromatic dihalogen sulfones. Preferably exactly one non-sulfonated aromatic dihalogen sulfone is used.

[0090] In the above preferred embodiments, "X" preferably represents the reaction mixture (R G ) in the reaction mixture (R G ) in the reaction mixture (R G ) is the sum of the molar amounts of component (A1) and component (A2) contained in the reaction mixture (R G ) is based on the total molar amount of component (A), "X 1 " means herein the molar amount of component (A1) in mol %, and "X 2 " refers herein to the molar amount of component (A2) in mol %.

[0091] X 1The amount of the solvent may be in the range of 2 mol.-% to 70 mol.-%, preferably in the range of 5 mol.-% to 65 mol.-%, more preferably in the range of 7.5 mol.-% to 60 mol.-% and most preferably in the range of 10 mol.-% to 57.5 mol.-%, in each case based on the reaction mixture (R G ) is the total molar amount of the aromatic dihalogen sulfone component (component (A)).

[0092] X 2 The amount of the esters may be in the range of 30 mol.-% to 98 mol.-%, preferably in the range of 35 mol.-% to 95 mol.-%, more preferably in the range of 40 mol.-% to 92.5 mol.-% and most preferably in the range of 42.5 mol.-% to 90 mol.-%, in each case based on the reaction mixture (R G ) is the total molar amount of the aromatic dihalogen sulfone component (component (A)).

[0093] X 1 and X 2 The amounts generally amount to 100 mol.-%.

[0094] In a preferred embodiment, based on the reaction mixture (R G ) in an amount of 2 to 70 mol.-% of component (A1) and 30 to 98 mol.-% of component (A2).

[0095] In a more preferred embodiment, based on the reaction mixture (R G ) in an amount of 5 to 65 mol.-% of component (A1) and 35 to 95 mol.-% of component (A2).

[0096] In an even more preferred embodiment, based on the reaction mixture (R G ) in an amount of 7.5 to 60 mol.-% of component (A1) and 40 to 92.5 mol.-% of component (A2).

[0097] In a particularly preferred embodiment, based on the reaction mixture (R G ) in an amount of at least 1 mol.-% to 57.5 mol.-% of component (A1) and at least 42.5 mol.-% to 90 mol.-% of component (A2).

[0098] Component (A1)

[0099] Component (A1) (which is also referred to as sulfonated aromatic dihalogen sulfone) preferably comprises at least one -SO3X 3 Group.

[0100] Component (A1) preferably contains at least one -SO3X 3 Group. In this article, "at least one -SO3X 3 "Group" means that component (A1) may contain exactly one -SO3X 3 group and two or more -SO3X 3 More preferably, component (A1) contains two -SO3X 3 Group.

[0101] General formula - SO3X 3 Contains sulfonic acid functional groups and derivatives of sulfonic acid functional groups such as sulfonates. 3 In the group, X 3 Can be hydrogen and / or a cation equivalent.

[0102] In the context of the present invention, reference to "a cation equivalent" means a cation of a single positive charge or a charge equivalent of a cation with two or more positive charges, such as Li, Na, K, Mg, Ca, NH4, preferably Na, K. Particularly preferred are Na or K.

[0103] Component (A1) is preferably selected from the group consisting of 4,4'-dichlorodiphenylsulfone-3,3'-disulfonic acid and 4,4'-difluorodiphenylsulfone-3,3'-disulfonic acid and derivatives thereof.

[0104] In the context of the present invention, the terms "sulfonic acid" and "-SO3X 3 "-SO3X" is used synonymously and has the same meaning. Thus, the term "sulfonic acid" in 4,4'-dichlorodiphenylsulfone-3,3'-disulfonic acid and 4,4'-difluorodiphenylsulfone-3,3'-disulfonic acid means "-SO3X 3 Group", where X 3 is hydrogen or a cation equivalent.

[0105] In one embodiment, component (A1) preferably comprises -SO3X with a cation equivalent 3Particularly preferably, component (A1) is selected from the group consisting of 4,4′-dichlorodiphenyl sulfone-3,3′-disulfonic acid, 4,4′-dichlorodiphenyl sulfone-3,3′-disulfonic acid disodium salt, 4,4′-dichlorodiphenyl sulfone-3,3′-disulfonic acid dipotassium salt, 4,4′-difluorodiphenyl sulfone-3,3′-disulfonic acid, 4,4′-difluoro-diphenyl sulfone-3,3′-disulfonic acid disodium salt and 4,4′-difluorodiphenyl sulfone-3,3′-disulfonic acid dipotassium salt.

[0106] Another object of the present invention is therefore a process, wherein component (A1) comprises at least one compound selected from the group consisting of 4,4′-dichlorodiphenyl sulfone-3,3′-disulfonic acid, 4,4′-dichloro-diphenyl sulfone-3,3′-disulfonic acid disodium salt, 4,4′-dichlorodiphenyl sulfone-3,3′-disulfonic acid dipotassium salt, 4,4′-difluorodiphenyl sulfone-3,3′-disulfonic acid, 4,4′-difluoro-diphenyl sulfone-3,3′-disulfonic acid disodium salt and 4,4′-difluorodiphenyl sulfone-3,3′-disulfonic acid dipotassium salt.

[0107] In one embodiment, based on the reaction mixture (R G ) in the total weight of component (A1), component (A1) comprises not less than 70wt%, preferably not less than 90wt%, and more preferably not less than 98wt% of at least one aromatic dihalogen sulfone component, the at least one aromatic dihalogen sulfone component comprising at least one -SO3X selected from the group consisting of 3 Groups: 4,4'-dichlorodiphenyl sulfone-3,3'-disulfonic acid, 4,4'-dichlorodiphenyl sulfone-3,3'-disulfonic acid disodium salt, 4,4'-dichlorodiphenyl sulfone-3,3'-disulfonic acid dipotassium salt, 4,4'-difluorodiphenyl sulfone-3,3'-disulfonic acid, 4,4'-difluorodiphenyl sulfone-3,3'-disulfonic acid disodium salt and 4,4'-difluorodiphenyl sulfone-3,3'-disulfonic acid dipotassium salt.

[0108] In another particularly preferred embodiment, component (A1) consists of at least one aromatic dihalogen sulfone comprising at least one -SO3X selected from the group consisting of 3 Groups: 4,4'-dichlorodiphenyl sulfone-3,3'-disulfonic acid, 4,4'-dichlorodiphenyl sulfone-3,3'-disulfonic acid disodium salt, 4,4'-dichlorodiphenyl sulfone-3,3'-disulfonic acid dipotassium salt, 4,4'-difluorodiphenyl sulfone-3,3'-disulfonic acid, 4,4'-difluorodiphenyl sulfone-3,3'-disulfonic acid disodium salt and 4,4'-difluorodiphenyl sulfone-3,3'-disulfonic acid dipotassium salt.

[0109] In these embodiments, 4,4'-dichlorodiphenyl sulfone-3,3'-disulfonic acid dipotassium salt and 4,4'-dichlorodiphenyl sulfone-3,3'-disulfonic acid disodium salt are particularly preferred for use as component (A1).

[0110] In a further particularly preferred embodiment, component (A1) consists of 4,4'-dichlorodiphenyl sulfone-3,3-disulfonic acid dipotassium salt or 4,4'-dichloro-diphenyl sulfone-3,3'-disulfonic acid disodium salt and mixtures thereof.

[0111] Component (A2)

[0112] Component (A2) (which is also referred to as the non-sulfonated aromatic dihalogen sulfone component) preferably does not contain -SO3X 3 Group.

[0113] Preferably, based on the reaction mixture (R G ) in the total weight of component (A2), component (A2) contains not less than 80 wt%, preferably not less than 90 wt%, and more preferably not less than 98 wt% of at least one aromatic dihalogen sulfone selected from the group consisting of 4,4'-dichlorodiphenyl sulfone and 4,4'-difluorodiphenyl sulfone. The weight percentages for component (A2) here also relate to the sum of the used 4,4'-dichlorodiphenyl sulfone and the used 4,4'-difluorodiphenyl sulfone.

[0114] Therefore, another object of the present invention is a process in which, based on the reaction mixture (R G ) in the total weight of component (A2), component (A2) comprising not less than 80 wt% of at least one aromatic dihalogen sulfone selected from the group consisting of 4,4′-dichlorodiphenyl sulfone and 4,4′-difluoro-diphenyl sulfone.

[0115] In a further particularly preferred embodiment, component (A2) consists of at least one aromatic dihalogen sulfone selected from the group consisting of 4,4'-dichlorodiphenyl-sulfone and 4,4'-difluorodiphenyl sulfone.

[0116] In these embodiments, 4,4'-dichlorodiphenyl sulfone is particularly preferably used as component (A2).

[0117] In a further particularly preferred embodiment, component (A2) consists of 4,4'-dichlorodiphenyl sulfone.

[0118] Preferably, component (A2) is selected from the group consisting of 4,4'-dichlorodiphenyl sulfone and 4,4'-difluorodiphenyl sulfone.

[0119] Component (B)

[0120] Component (B), which is also referred to as an aromatic dihydroxy compound, generally comprises two hydroxyl groups.

[0121] Reference herein to "at least one aromatic dihydroxy compound" is to exactly one aromatic dihydroxy compound as well as mixtures of two or more aromatic dihydroxy compounds. Preferably exactly one aromatic dihydroxy compound is used.

[0122] In the above preferred embodiments, "Y" preferably means the reaction mixture (R G ) in the reaction mixture (R G ) is the total molar amount of the aromatic dihydroxy compound (component (B)).

[0123] Preferably, component (B) is selected from the group consisting of 4,4'-dihydroxybiphenyl, 4,4'-dihydroxydiphenyl sulfone, bisphenol A (2,2-bis(4-hydroxyphenyl)propane), 4,4'-dihydroxybenzophenone, hydroquinone and hydroquinone derivatives. From among the above aromatic dihydroxy components, 4,4'-dihydroxybiphenyl, 4,4'-dihydroxydiphenyl sulfone and bisphenol A are preferred, and 4,4'-dihydroxybiphenyl is particularly preferred.

[0124] Therefore, the present invention also provides a process, wherein component (B) is selected from the group consisting of 4,4'-dihydroxybiphenyl, 4,4'-dihydroxydiphenyl sulfone, bisphenol A, 4,4'-dihydroxybenzophenone and hydroquinone.

[0125] Preferably, based on the reaction mixture (R G ) in the total weight of component (B), component (B) contains not less than 80 wt%, preferably not less than 90 wt%, and more preferably not less than 98 wt% of 4,4'-dihydroxybiphenyl.

[0126] Therefore, another object of the present invention is a process in which, based on the reaction mixture (R G ) in the total weight of component (B), component (B) contains not less than 80 wt% of 4,4'-dihydroxybiphenyl.

[0127] The percentages by weight for component (B) here further relate to the sum of the 4,4'-dihydroxybiphenyl, 4,4'-dihydroxydiphenyl sulfone, bisphenol A (2,2-bis-(4-hydroxyphenyl)propane), 4,4'-dihydroxybenzophenone and hydroquinone used.

[0128] In another particularly preferred embodiment, component (B) consists of at least one aromatic dihydroxy component selected from the group consisting of 4,4′-dihydroxybiphenyl, 4,4′-dihydroxydiphenyl sulfone, bisphenol A (2,2-bis(4-hydroxy-phenyl)propane), 4,4′-dihydroxybenzophenone and hydroquinone.

[0129] In these embodiments, 4,4'-dihydroxybiphenyl, bisphenol A, and 4,4'-dihydroxydiphenyl sulfone are particularly preferred for use as component (B), with 4,4'-dihydroxybiphenyl being most preferred.

[0130] Component (D )

[0131] Reaction mixture (R G ) comprises at least one carbonate compound as component (C). In this case, the term "at least one carbonate compound" is understood to mean exactly one carbonate compound, and also a mixture of two or more carbonate compounds. The at least one carbonate compound is preferably at least one metal carbonate. The metal carbonate is preferably anhydrous. In this case, the terms "at least one carbonate compound" and "component (C)" are used synonymously and therefore have the same meaning.

[0132] Alkali metal carbonates and / or alkaline earth metal carbonates are preferred as metal carbonates. At least one metal carbonate selected from the group consisting of sodium carbonate, potassium carbonate and calcium carbonate is particularly preferred as metal carbonate. Potassium carbonate is most preferred.

[0133] For example, based on the reaction mixture (R G ), component (C) comprises not less than 50 wt%, more preferably not less than 70 wt%, and most preferably not less than 90 wt% potassium carbonate by weight, based on the total weight of the at least one carbonate component in the composition.

[0134] Therefore, another object of the present invention is a process in which, based on the reaction mixture (R G ) in the present invention, the component (C) contains not less than 50 wt % of potassium carbonate, based on the total weight of the component (C).

[0135] In a preferred embodiment, component (C) consists of potassium carbonate. Potassium carbonate having a volume-weighted average particle size of less than 200 μm, more preferably less than 100 μm, even more preferably less than 70 μm, and most preferably less than 50 μm is preferably potassium carbonate. The volume-weighted average particle size of potassium carbonate is determined using a particle size analyzer in a suspension of potassium carbonate in a mixture of chlorobenzene / sulfolane (60 / 40 by weight).

[0136] In the above preferred embodiments, "Z" preferably means the reaction mixture (R G ) in the reaction mixture (R G ) in the total molar amount of at least one carbonate component (component (C)).

[0137] Z is in the range of P to Q.

[0138] "P" is calculated according to the following formula:

[0139] P=Y*(1.05+X 1 / 100*1.05)

[0140] "Q" is calculated according to the following formula:

[0141] Q=Y*(1.05+X 1 / 100*1.4)

[0142] In this formula, Y is the reaction mixture (R G ) in the molar amount of component (B), and X 1 Also the reaction mixture (R G ) in mol.-% value of component (A1).

[0143] Component (D)

[0144] Reaction mixture (R G ) preferably comprises at least one aprotic polar solvent as component (D). According to the invention, "at least one aprotic polar solvent" is understood to mean exactly one aprotic polar solvent and also mixtures of two or more aprotic polar solvents. In this case, the terms "at least one aprotic polar solvent" and "component (D)" are used synonymously and therefore have the same meaning.

[0145] Suitable aprotic polar solvents are, for example, selected from anisole, dimethylformamide, dimethyl sulfoxide, sulfolane, N-methylpyrrolidone, N-ethylpyrrolidone and N-dimethylacetamide.

[0146] Preferably, component (D) is selected from the group consisting of: N-methylpyrrolidone, N-dimethylacetamide, dimethyl sulfoxide and dimethylformamide. N-methylpyrrolidone is particularly preferred as component (D).

[0147] Preferably, based on the reaction mixture (R G), component (D) contains not less than 50 wt %, preferably not less than 70 wt %, and more preferably not less than 90 wt % of at least one solvent selected from the group consisting of: N-methylpyrrolidone, N-dimethylacetamide, dimethyl sulfoxide and dimethylformamide. N-methylpyrrolidone is particularly preferred as component (D).

[0148] Another object of the present invention is therefore a process in which component (D) comprises a mixture based on the reaction mixture (R G ) in the total weight of component (D), not less than 50wt% of at least one solvent selected from the group consisting of N-methylpyrrolidone, N-dimethylacetamide, dimethyl sulfoxide and dimethyl-formamide.

[0149] In a preferred embodiment, component (D) consists of N-methylpyrrolidone, which is also known as NMP or N-methyl-2-pyrrolidone.

[0150] The sulfonated polyarylene sulfone polymer (sP) obtained in step i) is described in more detail hereinafter.

[0151] The sulfonated polyarylene sulfone polymer (sP) obtained in step i)

[0152] The sulfonated polyarylene sulfone polymer (sP) obtained in step i) of the process according to the invention preferably comprises repeating units of the general formula I:

[0153]

[0154] in

[0155] t and q: each independently 0, 1, 2 or 3,

[0156] Q 1 , T and Y 1 : Each independently is a chemical bond or is selected from -O-, -S-, -SO2-, -S(=O)-, -C(=O)-, -N=N- and -CR a R b -,

[0157] Where R a and R b are independently a hydrogen atom or a C1-C 12 -alkyl, C1-C 12 -alkoxy or C6-C 18 -aryl group, and wherein at least one of Q, T and Y is -SO2-,

[0158] Ar and Ar 1 : Each independently is C6-C 18 Aryl, wherein the C6-C18 The aryl group is unsubstituted or substituted by at least one substituent selected from the group consisting of: C1-C 12 Alkyl, C1-C 12 Alkoxy, C6-C 18 Aryl, halogen and -SO-3X,

[0159] p, m, n and k: each independently 0, 1, 2, 3 or 4, provided that the sum of p, m, n and k is not less than 1, and

[0160] X 3 : is hydrogen or a cation equivalent.

[0161] Therefore, another object of the present invention is a process, wherein the sulfonated polyarylene sulfone polymer (sP) obtained in step i) comprises recurring units of the general formula (I) as defined above.

[0162] In a preferred embodiment, the sulfonated polyarylene sulfone polymer (sP) obtained in step i) comprises at least 80 mol.-% of repeating units of the general formula (I), based on the total molar amount of the sulfonated polyarylene sulfone polymer (sP) obtained in step i).

[0163] If under the above premise, Q 1 , T or Y 1 is a chemical bond, then this means that the adjacent group on the left-hand side and the adjacent group on the right-hand side are directly connected to each other by a chemical bond.

[0164] R a and R b are independently hydrogen or C1-C 12 alkyl.

[0165] Preferred C1-C 12 Alkyl groups include straight and branched saturated alkyl groups having 1 to 12 carbon atoms. The following moieties are particularly suitable: C1-C6 alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, 2-methylpentyl or 3-methylpentyl, and relatively long chain moieties such as unbranched heptyl, octyl, nonyl, decyl, undecyl, lauryl, and branched analogs thereof.

[0166] C1-C used 12 The alkyl moiety in the alkoxy group includes the alkyl groups having 1 to 12 carbon atoms as defined above. The cycloalkyl moieties preferably used include in particular C3-C 12Cycloalkyl moieties, for example, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclopropylmethyl, cyclopropylethyl, cyclopropylpropyl, cyclobutylmethyl, cyclobutylethyl, cyclopentylethyl, cyclopentylpropyl, cyclopentylbutyl, cyclopentylpentyl, cyclopentylhexyl, cyclopentylcyclohexylmethyl, -cyclopentyldimethyl, cyclopentyltrimethyl.

[0167] Ar and Ar 1 Each independently is C6-C 18 Aryl. From the starting materials herein, Ar is preferably derived from an electron-rich aromatic substance that is very susceptible to electrophilic attack, preferably selected from the group consisting of sulfonated or unsulfonated hydroquinone, resorcinol, dihydroxynaphthalene (especially 2,7-dihydroxynaphthalene). Ar 1 Preferably, it is unsubstituted C6 or C 12 Arylene group.

[0168] In a preferred embodiment, Ar and Ar of formula (I) 1 Preferably they are each independently selected from the group consisting of sulfonated or non-sulfonated 1,4-phenylene, 1,3-phenylene, naphthylene, in particular 2,7-dihydroxynaphthalene and 4,4'-biphenylene.

[0169] Preferred are sulfonated polyarylene sulfone polymers (sP) having one or more of the following structural units (Ia) to (Io):

[0170]

[0171]

[0172]

[0173] in

[0174] l, k, m, n, o, p are each independently 0, 1, 2, 3 or 4, provided that the sum of l, k, m, n, o and p is ≥ 1, and

[0175] X 3 is hydrogen or a cation equivalent.

[0176] In the context of the present invention, reference to "a cation equivalent" means a cation of a single positive charge or a charge equivalent of a cation carrying two or more positive charges, such as Li, Na, K, Mg, Ca, NH4, preferably Na, K.

[0177] In addition to the preferred building blocks (Ia) to (Io), preference is also given to those structural units in which one or more sulfonated or nonsulfonated 1,4-dihydroxyphenyl units are replaced by resorcinol or dihydroxynaphthalene.

[0178] More preferred sulfonated polyarylene sulfone polymers (sP) are those which contain at least 80 mol.-%, particularly preferably at least 90 mol.-% and particularly preferably at least 98 mol.-% of one or more of the units Ia to Io as repeating structural units, based on the total molar amount of the sulfonated polyarylene sulfone polymer (sP) obtained in step i).

[0179] Particularly preferred sulfonated polyarylene sulfone polymers (sP) are those which contain at least 80 mol.-%, particularly preferably at least 90 mol.-% and particularly preferably at least 98 mol.-%, of one or more of the units Ia, Ig and / or Ik as repeating structural units, based on the total molar amount of the sulfonated polyarylene sulfone polymer (sP) obtained in step i).

[0180] Particularly preferred sulfonated polyarylene sulfone polymers (sP) are at least one polymer selected from sulfonated polyphenylene sulfone (sPPSU), sulfonated polyether sulfone (sPESU) and sulfonated polysulfone (sPSU), wherein sulfonated polyphenylene sulfone (sPPSU) is especially preferred.

[0181] Sulfonated polyphenylene sulfone (sPPSU) is formed from the aforementioned repeating unit formula Ig. Sulfonated polysulfone (sPSU) is formed from the aforementioned repeating unit Ia. Sulfonated polyethersulfone (sPESU) is formed from the aforementioned repeating unit formula Ik.

[0182] Copolymers composed of various combinations of structural units or composed of sulfonated and non-sulfonated structural units are also useful.

[0183] In particularly preferred cases, the structural units (Ia), (Ib), (Ig) and (Ik) or copolymers thereof are used as repeating units of the general formula (I).

[0184] In a particularly preferred embodiment, Ar is 1,4-phenylene, t is 1, T is a chemical bond, and Y 1 is -SO2-, q is 0, p is 0, m is 0, n is 1 and k is 1. Sulfonated polyphenylene sulfone composed of the above-mentioned structural repeating units is represented by sPPSU.

[0185] In a particularly preferred embodiment, Ar is 1,4-phenylene, t is 0, Y is -SO2-, q is 0, n is 0 and k is 0. Polyarylene sulfones composed of this listed structural repeating unit are referred to as sulfonated polyetherethersulfones (sPEES).

[0186] In an advantageous embodiment, the sulfonated polyarylene sulfone polymer (sP) obtained in step i) comprises

[0187] The non-sulfonated repeating unit of formula (1)

[0188]

[0189] and the sulfonated repeating unit of formula (2)

[0190]

[0191] In particular, the sulfonated polyarylene sulfone polymer (sP) obtained in step i) consists exclusively of non-sulfonated repeating units of formula (1) and sulfonated repeating units of formula (2).

[0192]

[0193] The sulfonated polyarylene sulfone polymer (sP) obtained in step i) according to the invention preferably has a viscosity number of 20 ml / g to 250 ml / g, preferably 50 ml / g to 200 ml / g. The viscosity number is quantified in accordance with DIN EN ISO 1628-1 at 25° C. in a 1% solution in N-methylpyrrolidone (NMP). The measurement can also be carried out at lower polymer concentrations (e.g. 0.5%).

[0194] The weight average molecular weight (M) of the sulfonated polyarylene sulfone polymer (sP) obtained in step i) is w ) is generally in the range of 10000 g / mol to 250000 g / mol, preferably in the range of 15000 g / mol to 200000 g / mol, and more preferably in the range of 18000 g / mol to 150000 g / mol. The weight average molecular weight (M) is measured using gel permeation chromatography (GPC). w ). Dimethylacetamide (DMAc) was used as a solvent, and narrow distribution polymethyl methacrylate was used as a standard in the measurement.

[0195] Step ii)

[0196] In step ii), from the product mixture (P G ) is removed during the condensation reaction in step i). A first solution (S1) comprising the sulfonated polyarylene sulfone polymer (sP) and component (D) is obtained.

[0197] The inorganic halide compounds can be removed by means known in the art, such as filtration, centrifugation, decantation, and the like.

[0198] Therefore, the present invention also provides a method, wherein the method comprises the steps of

[0199] ii) treating the product mixture (P) obtained in step i) G ) is filtered, centrifuged and / or decanted to obtain a first solution (S1).

[0200] In a preferred embodiment, the first solution (S1) obtained in step ii) does not contain solid inorganic halide compounds. In a further preferred embodiment, based on the total weight of the first solution (S1) obtained in step ii), the first solution (S1) obtained in step ii) contains less than 3 wt%, more preferably less than 1.5 wt% and particularly preferably less than 0.5 wt% of inorganic halide components.

[0201] In a more preferred embodiment, the first solution (S1 ) obtained in step ii) contains no solid inorganic compounds.

[0202] In a further preferred embodiment, the first solution (S1) obtained in step ii) contains less than 0.4 wt %, more preferably less than 0.3 wt % and particularly preferably less than 0.2 wt % of inorganic components, based on the total weight of the first solution (S1) obtained in step ii).

[0203] In a preferred embodiment, the sulfonated polyarylene sulfone polymer (sP) in step ii) is not isolated from the first solution (S1).

[0204] In one embodiment, between step ii) and step iii), no further process steps are carried out.

[0205] In a further preferred embodiment, the sulfonated polyarylene sulfone polymer (sP) in the first solution (S1) in step ii) remains in dissolved form before step iii) is carried out.

[0206] Step iii)

[0207] In step iii), at least one further polymer (fP) is mixed with the first solution (S1) to obtain a second solution (S2). In a preferred embodiment, in step iii), at least one pore former (pA) is additionally mixed with the first solution (S1) to obtain a second solution (S2).

[0208] In a preferred embodiment, in step iii), at least one further polymer (fP) and at least one pore former (pA) are mixed with the first solution (S1) to obtain a second solution (S2).

[0209] "At least one further polymer (fP)" herein means exactly one further polymer (fP) as well as a mixture of two or more further polymers (fP). "At least one pore former (pA)" herein means exactly one pore former (pA) as well as a mixture of two or more pore formers (pA).

[0210] The at least one further polymer (fP) is preferably at least one polyarylene sulfone polymer which may be sulfonated or non-sulfonated. The sulfonated polyarylene sulfone polymer (sP) and the at least one further polymer (fP) are different from each other. Preferably, the at least one further polymer (fP) is at least one non-sulfonated polyarylene sulfone polymer.

[0211] Preferred further polymers (fP) are those which comprise as repeating structural unit at least one of the following units IIa to IIo:

[0212]

[0213]

[0214] More preferably, further polymers (fP) are those which contain as repeating structural units at least 80 mol.-%, particularly preferably at least 90 mol.-% and particularly preferably at least 98 mol.-%, based on the total molar amount of the further polymer (fP), of one or more of the units IIa to IIo.

[0215] As further polymers (fP), those which contain as repeating structural units at least 80 mol.%, particularly preferably at least 90 mol.%, and particularly preferably at least 98 mol.%, based on the total molar amount of the further polymer (fP), one or more of the units IIa, IIg and / or IIk.

[0216] Particularly preferred further polymers (fP) are at least one polymer selected from the group consisting of polyphenylene sulfone (PPSU), polyether sulfone (PESU) and polysulfone (PSU), wherein polyether sulfone (PESU) is especially preferred.

[0217] Polyphenylene sulfone (PPSU) is formed from the aforementioned repeating unit formula IIg. Polysulfone (PSU) is formed from the aforementioned repeating unit IIa. Polyethersulfone (PESU) is formed from the aforementioned repeating unit formula IIk.

[0218] In the context of the present invention, abbreviations such as PPSU, PESU and PSU correspond to DIN EN ISO 1043-1 (Plastics - Symbols and abbreviated terms - Part 1: Base polymers and their special characteristics (ISO 1043-1:2001); German version EN ISO 1043-1:2002).

[0219] Preferably the pore former (pA) is for example selected from the group consisting of polyvinylpyrrolidone (PVP) polyethylene oxide, polypropylene oxide and polyethylene oxide-polypropylene oxide copolymers.

[0220] In step iv), the pore former (pA), if present, is at least partially removed from the precipitated film and pores remain in the membrane (M).

[0221] In a particularly preferred embodiment, the sulfonated polyarylene sulfone polymer (sP) in the process according to the invention remains dissolved until step iv) is carried out.

[0222] In a further particularly preferred embodiment, the sulfonated polyarylene sulfone polymer (sP) is not isolated before carrying out step iv). In other words, the process according to the invention preferably comprises only one isolation step (step iv)) of the sulfonated polyarylene sulfone polymer (sP), in which the membrane (M) is formed.

[0223] Step iv)

[0224] In step iv), at least one aprotic polar solvent is separated from the second solution (S2) to obtain the membrane (M). In a preferred embodiment, the second solution (S2) is degassed before performing step iv).

[0225] In step iv), the pore former (pA) is at least partially removed from the second solution (S2) if added in step iii). In the context of the present invention, "at least partially removed" means that at least 50% of the total amount of pore former (pA) added in step iii) is removed from the second solution (S2).

[0226] The separation of the at least one aprotic polar solvent and, if present, the porogen (pA) from the second solution (S2) in step iv) can be carried out by any method known to the person skilled in the art suitable for separating aprotic solvents and porogens from polymers.

[0227] Preferably, the separation of the at least one aprotic polar solvent and, if present, the porogen (pA) from the second solution (S2) in step iv) is performed via a phase inversion process.

[0228] In the context of the present invention, a phase inversion process is understood to mean a process in which a dissolved sulfonated polyarylene sulfone polymer (sP) is converted into a solid phase. Thus, a phase inversion process can also be indicated as a precipitation process. According to step iv), the conversion is preferably carried out by separating at least one aprotic polar solvent and, if present, the pore former (pA) from the sulfonated polyarylene sulfone polymer (sP). Suitable phase inversion processes are known to the person skilled in the art.

[0229] The phase inversion method can preferably be carried out by contacting the second solution (S2) with a protic polar liquid, which is a non-solvent for the sulfonated polyarylene sulfone polymer (sP) and in which the pore former (pA) is soluble. The sulfonated polyarylene sulfone polymer (sP) will then precipitate. Suitable protic polar solvents that are non-solvents for the sulfonated polyarylene sulfone polymer (sP) are, for example, the protic polar solvents described below in their liquid state. Another phase inversion method preferred in the context of the present invention is a phase inversion performed by immersing the second solution (S2) in at least one protic polar solvent.

[0230] Therefore, in one embodiment, in step iv), the at least one aprotic polar solvent contained in the second solution (S2) is separated from the sulfonated polyarylene sulfone polymer (sP) contained in the second solution (S2) by immersing the second solution (S2) in at least one protic polar solvent.

[0231] This means that the membrane (M) in step iv) is formed by immersing the second solution (S2) in at least one protic polar solvent.

[0232] Suitable at least one protic polar solvent is known to the skilled person. Preferred at least one protic polar solvent is water, methanol, ethanol, n-propanol, isopropanol, glycerol, ethylene glycol and mixtures thereof.

[0233] Therefore, in a preferred embodiment, step iv) comprises the following steps:

[0234] iv-1) casting the second solution (S2) provided in step iii) to obtain a film of the second solution (S2),

[0235] iv-2) separating the at least one aprotic polar solvent from the membrane of the solution (S) obtained in step iii-1) to obtain a membrane (M) in the form of a membrane.

[0236] The separation in step iv-2) can be performed as described above. Preferably, the separation in step iv-2) is performed by immersing the membrane of the second solution (S2) in at least one protic polar solvent.

[0237] Therefore, in a particularly preferred embodiment, step iv) comprises the following steps:

[0238] iv-1) casting the second solution (S2) provided in step iii) to obtain a film of the second solution (S2),

[0239] iv-2) Immersing the membrane of the second solution (S2) obtained in step iv-1) in at least one protic polar solvent to obtain a membrane (M) in the form of a membrane.

[0240] In step iv-1), the second solution (S2) can be cast by any method known to the skilled person. Typically, the second solution (S2) is cast with a casting knife, a comet bar, a Meyer bar, a slot die or a reverse roll preferably heated to a temperature in the range of 20°C to 150°C, preferably in the range of 40°C to 100°C, more preferably between 60°C and 85°C.

[0241] In step iv-1), the second solution (S2) is generally cast on a substrate (support material) which does not react with the sulfonated polyarylene sulfone polymer (sP) and / or the at least one solvent contained in the second solution (S2).

[0242] Suitable substrates (carrier materials) are, for example, steel belts, drying cylinders or polymer films. The substrate (carrier material) is usually not part of the finished membrane (M), but is only used for processing purposes.

[0243] The second solution (S2) may also be cast on a porous support layer forming part of the membrane (M).

[0244] For the preparation of single-hole hollow fibers or multi-hole hollow fibers, step iv) can be performed by extruding the second solution (S2) through an extrusion nozzle with a desired number of hollow needles. Then, during extrusion, a coagulation liquid (at least one protic solvent) is injected through the hollow needles into the extruded second solution (S2), so that parallel continuous channels extending in the extrusion direction are formed in the extruded second solution (S2). Preferably, the pore size on the outer surface of the extruded membrane (M) is controlled by contacting the outer surface with a mild coagulant after leaving the extrusion nozzle, so that the shape is fixed without an active layer on the outer surface, and then contacting the membrane with a strong coagulant, or vice versa.

[0245] Diaphragm(M)

[0246] Typically, the separator (M) comprises:

[0247] 1 to 99.5 wt. % of a sulfonated polyarylene sulfone polymer (sP), and

[0248] 0.5 to 99 wt. % of at least one further polymer (fP).

[0249] Preferably, based on the total weight of the separator (M), the separator (M) comprises

[0250] 2 to 97.5 wt. % of a sulfonated polyarylene sulfone polymer (sP), and

[0251] 2.5 to 98 wt. % of at least one further polymer (fP).

[0252] More preferably, based on the total weight of the separator (M), the separator (M) comprises

[0253] 2.5 to 95 wt. % of a sulfonated polyarylene sulfone polymer (sP), and

[0254] 5% to 97.5% by weight of at least one further polymer (fP).

[0255] Even more preferably, the separator (M) comprises, based on the total weight of the separator (M),

[0256] 3.5 to 90 wt. % of a sulfonated polyarylene sulfone polymer (sP), and

[0257] 10% to 96.5% by weight of at least one further polymer (fP).

[0258] Particularly preferably, the separator (M) comprises, based on the total weight of the separator (M),

[0259] 5 to 90 wt. % of a sulfonated polyarylene sulfone polymer (sP), and

[0260] 10 to 95 wt. % of at least one further polymer (fP).

[0261] If a pore former is present, the separator (M) generally comprises:

[0262] 1% to 99.45% by weight of sulfonated polyarylene sulfone polymer (sP),

[0263] 0.5% to 98.95% by weight of at least one further polymer (fP), and

[0264] 0.05 wt% to 10 wt% of porogen (pA).

[0265] Preferably, based on the total weight of the separator (M), the separator (M) comprises

[0266] 2 to 97.4 wt. % of a sulfonated polyarylene sulfone polymer (sP),

[0267] 2.5 to 97.9 wt. % of at least one further polymer (fP), and

[0268] 0.1 wt% to 5 wt% porogen (pA).

[0269] More preferably, based on the total weight of the separator (M), the separator (M) comprises

[0270] 2.5 to 94.85 wt. % of a sulfonated polyarylene sulfone polymer (sP),

[0271] 5% to 97.35% by weight of at least one further polymer (fP), and

[0272] 0.15 wt% to 4 wt% porogen (pA).

[0273] Even more preferably, the separator (M) comprises, based on the total weight of the separator (M),

[0274] 3.5 to 89.8 wt. % of a sulfonated polyarylene sulfone polymer (sP),

[0275] 10% to 96-3% by weight of at least one further polymer (fP), and

[0276] 0.2 wt% to 4 wt% porogen (pA).

[0277] In particular, based on the total weight of the separator (M), the separator (M) comprises

[0278] 5 to 89.8 wt. % of sulfonated polyarylene sulfone polymer (sP),

[0279] 10% to 94.8% by weight of at least one further polymer (fP), and

[0280] 0.2 to 3 wt% porogen (pA).

[0281] The membrane (M) preferably has a pressure of >25 kg / (hm2) determined using a pressure cell with a diameter of 74 mm using ultrapure water (no saline, filtered through a Millipore UF system) at 23°C and a water pressure of 1 bar. 2 bar). The pure water permeability (PWP) is calculated as follows (Formula (1)):

[0282]

[0283] PWP: Pure water permeability [kg / bar hm 2 ]

[0284] m: Mass of permeate water [kg]

[0285] A: Diaphragm area [m 2 ]

[0286] P: Pressure [bar]

[0287] t: time of penetration experiment [h].

[0288] The membrane (M) preferably has a surface area of ​​>1 m / s as determined by gas adsorption-desorption (GAD) experiments with nitrogen using the Brunauer-Emmet-Teller (BET) surface model. 2 / g of surface area.

[0289] In a preferred embodiment, the separator has a contact angle of 30° to 70°.

[0290] 8 to 10 drops of deionized water with a volume of about 2 μL were placed on the sample at 23°C and the sample was analyzed by Krüss DSA100 (A. Optronic GmbH, Hamburg, Germany) to determine the contact angles by time-resolved automated image analysis.

[0291] Equipment including diaphragm (M)

[0292] Another object of the present invention is a device comprising the membrane (M) obtained by the process of the present invention. The device is preferably an ultrafiltration device.

[0293] Preferred ultrafiltration devices are selected from dialysis devices and pure water production devices.

[0294] In order to use the diaphragm (M) obtained by the method of the present invention, in a preferred embodiment, the diaphragm (M) is activated. The activation can be carried out by contacting the diaphragm (M) with an acidic aqueous solution such as an aqueous mineral acid. Preferably, an aqueous sulfuric acid (H2SO4) solution is used for activation. The concentration of the acidic aqueous solution is preferably in the range of 0.1M to 4.0M. After the diaphragm (M) is contacted with an acidic aqueous solution such as an aqueous sulfuric acid solution, the diaphragm can be contacted with water, preferably deionized water. After activation, the diaphragm (M) is usually in the form of H2SO4. + Obtained in form.

[0295] In other words, after activation, the sulfonated polyarylene sulfone polymer (sP) contained in the membrane (M) contains -SO3X 3 The total molar amount of the groups is at least 70 mol.-%, more preferably at least 80 mol.-%, and particularly preferably at least 90 mol.-% -SO3H groups.

[0296] The present invention is more particularly illustrated by the following examples without being restricted thereto.

[0297] Components used :

[0298] DCDPS 4,4'-dichlorodiphenyl sulfone,

[0299] sDCDPS 4,4'-dichlorodiphenylsulfone-3,3'-disulfonic acid disodium salt

[0300] BP 4,4'-dihydroxybiphenyl,

[0301] K2CO3: Potassium carbonate, anhydrous, average particle size 32.6 μm

[0302] NMP: N-Methylpyrrolidone, anhydrous

[0303] PVP: Polyvinylpyrrolidone ( K40); pore former (pA)

[0304] PESU: Polyethersulfone ( E 6020P); other polymers (fP)

[0305] The viscosity number VN of the sulfonated polyarylene sulfone polymers (sP) was measured in 1% by weight NMP solution in accordance with DIN ISO 1628-1.

[0306] In CDCl3 by 1 H-NMR was used to determine the incorporation rate (incorporation rate) of sDCDPS. 1 The polymer content of the polymer solution after filtration was quantified by H-NMR.

[0307] Unless otherwise indicated, the sulfonated polyarylene sulfone polymer (sP) is isolated by dropping a solution of the sulfonated polyarylene sulfone polymer (sP) in NMP into isopropanol at room temperature. The drop height is 0.5 m. The throughput is about 2.5 l per hour. The precipitate obtained is then extracted with water at 85° C. (water throughput 160 l / h) for twenty hours. The precipitate is then dried at a temperature below the glass transition temperature Tg to a residual water content of less than 0.5% by weight.

[0308] Filtration of the product mixture was performed in a heated metal pressure filter using a filter with a pore size of 5 μm and a N2 pressure of 3 bar. The filter was heated to 60°C to reduce the viscosity of the reaction mixture.

[0309] The yield of polymer after precipitation was determined gravimetrically.

[0310] Comparative Example 1: C1p and C1sol :

[0311] In a 4-liter glass reactor equipped with a thermometer, a gas inlet tube and a Dean-Stark separator, 470.942 g (1.64 mol) of DCDPS, 196.50 g (0.4 mol) of sDCDPS, 372.42 g (2.00 mol) of BP and 304.052 g (2.20 mol) of potassium carbonate having a volume average particle size of 32.6 μm were suspended in 1250 ml of NMP in a nitrogen atmosphere.

[0312] The mixture was heated to 190° C. within one hour. In the following, reaction time is understood to mean the time during which the reaction mixture was kept at 190° C. The water formed in the reaction was removed continuously by distillation.

[0313] After a reaction time of 16 hours, the reaction was stopped by adding 1750 ml of NMP and cooling to room temperature (within one hour). The potassium chloride formed in the reaction was removed by filtration. The polymer solution obtained was then divided into two parts. One part was precipitated in isopropanol, the resulting polymer precipitate was separated, and then extracted with hot water (85° C.) for 20 h. The precipitated material was then dried at 120° C. for 24 h under reduced pressure (<100 mbar). The precipitated sulfonated polyarylene sulfone polymer (sP) is hereinafter named (C1p).

[0314] The filtrate is named (C1sol) hereinafter. 1 The filtrate was characterized by H-NMR (content based on sDCDPS units, polymer content).

[0315] Comparative Example 2: C2p and C2sol :

[0316] In a 4-liter glass reactor equipped with a thermometer, a gas inlet tube and a Dean-Stark separator, 470.942 g (1.64 mol) of DCDPS, 196.50 g (0.4 mol) of sDCDPS, 372.42 g (2.00 mol) of BP and 331.704 g (2.40 mol) of potassium carbonate having a volume average particle size of 32.6 μm were suspended in 1250 ml of NMP in a nitrogen atmosphere.

[0317] The mixture was heated to 190° C. within one hour. In the following, reaction time is understood to mean the time during which the reaction mixture was kept at 190° C. The water formed in the reaction was removed continuously by distillation.

[0318] After a reaction time of 16 hours, the reaction was stopped by adding 1750 ml of NMP and cooling to room temperature (within one hour). The potassium chloride formed in the reaction was removed by filtration. The polymer solution obtained was then divided into two parts. One part was precipitated in isopropanol, separated and then extracted with hot water (85° C.) for 20 h. The precipitated material was then dried at 120° C. for 24 h under reduced pressure (<100 mbar). The precipitated sulfonated polyarylene sulfone polymer (sP) is hereinafter referred to as (Cp).

[0319] The filtrate is named (C2sol) hereinafter. 1 The filtrate was characterized by H-NMR (content based on sDCDPS units, polymer content).

[0320] Example 3 :

[0321] In a 4-liter glass reactor equipped with a thermometer, a gas inlet tube and a Dean-Stark separator, 470.942 g (1.64 mol) of DCDPS, 196.50 g (0.4 mol) of sDCDPS, 372.42 g (2.00 mol) of BP and 359.35 g (2.60 mol) of potassium carbonate having a volume average particle size of 32.6 μm were suspended in 1250 ml of NMP in a nitrogen atmosphere.

[0322] The mixture was heated to 190° C. within one hour. In the following, reaction time is understood to mean the time during which the reaction mixture was kept at 190° C. The water formed in the reaction was removed continuously by distillation.

[0323] After a reaction time of 7 h, the reaction was stopped by adding 1750 ml of NMP and cooling to room temperature (within one hour). The potassium chloride formed in the reaction was removed by filtration. The polymer solution obtained was then divided into two parts. One part was precipitated in isopropanol (3p), separated and then extracted with hot water (85° C.) for 20 h. The precipitated material was then dried at 120° C. for 24 h under reduced pressure (<100 mbar). The precipitated sulfonated polyarylene sulfone polymer (sP) is hereinafter named (C1p).

[0324] The filtrate is named (C1sol) hereinafter. 1 The filtrate was characterized by H-NMR (content based on sDCDPS units, polymer content).

[0325] Comparative Example 4 :

[0326] In a 4-liter glass reactor equipped with a thermometer, a gas inlet tube and a Dean-Stark separator, 442.226 g (1.54 mol) of DCDPS, 245.625 g (0.50 mol) of sDCDPS, 372.42 g (2.00 mol) of BP and 317.88 g (2.30 mol) of potassium carbonate having a volume average particle size of 32.6 μm were suspended in 1250 ml of NMP in a nitrogen atmosphere.

[0327] The mixture was heated to 190° C. within one hour. In the following, reaction time is understood to mean the time during which the reaction mixture was kept at 190° C. The water formed in the reaction was removed continuously by distillation.

[0328] After a reaction time of 16 hours, the reaction was stopped by adding 2312 ml of NMP and cooling to room temperature (within one hour). The potassium chloride formed in the reaction was removed by filtration. The polymer solution obtained was then precipitated in isopropanol, the resulting polymer beads were separated and subsequently extracted with hot water (85° C.) for 20 h. The precipitate was then dried at 120° C. for 24 h under reduced pressure (<100 mbar). The precipitated sulfonated polyarylene sulfone polymer (sP) is hereinafter referred to as (C4p).

[0329] Example 5 :

[0330] In a 4-liter glass reactor equipped with a thermometer, a gas inlet tube and a Dean-Stark separator, 442.226 g (1.54 mol) of DCDPS, 245.625 g (0.50 mol) of sDCDPS, 372.42 g (2.00 mol) of BP and 373.17 g (2.70 mol) of potassium carbonate having a volume average particle size of 32.6 μm were suspended in 1250 ml of NMP in a nitrogen atmosphere.

[0331] The mixture was heated to 190° C. within one hour. In the following, reaction time is understood to mean the time during which the reaction mixture was kept at 190° C. The water formed in the reaction was removed continuously by distillation.

[0332] After a reaction time of 7.5 hours, the reaction was stopped by adding 2312 ml of NMP and cooling to room temperature (within one hour). The potassium chloride formed in the reaction was removed by filtration. The polymer solution obtained was then divided into two parts. One part was precipitated in isopropanol, separated and then extracted with hot water (85° C.) for 20 h. The precipitated material was then dried at 120° C. for 24 h under reduced pressure (<100 mbar). The precipitated sulfonated polyarylene sulfone polymer (sP) is hereinafter named (5p).

[0333] The filtrate is designated as (5sol) hereinafter. 1 The filtrate was characterized by H-NMR (content based on sDCDPS units, polymer content).

[0334] The characterization of the precipitated sulfonated polyarylene sulfone polymer (sP) and the obtained solution is shown in Table 1:

[0335] Table 1 :

[0336]

[0337] Using excess potassium carbonate according to the present invention, high molecular weight copolymers with high amounts of incorporated sDCDPs can be prepared.

[0338] Diaphragm preparation

[0339] For membrane preparation, different solutions including sulfonated polyarylene sulfone polymer (sP), NMP, PVP and PESU were prepared. In the present invention examples, the obtained solution of sulfonated polyarylene sulfone polymer (sP) was used, while in the comparative examples, the precipitation of sulfonated polyarylene sulfone polymer (sP) was used.

[0340] The amounts of the components (sulfonated polyarylene sulfone polymer (sP), NMP, PVP, and PESU) used to prepare the membrane-forming solution are shown in Table 2.

[0341] The components were added to a three-necked flask equipped with a magnetic stirrer. The mixture was heated at 60°C with gentle agitation until a uniform, clear, viscous solution was obtained. The solution was degassed overnight at room temperature. The membrane solution was then heated at 60°C for another 2 hours and cast onto a glass plate with a casting knife (300 microns) at 60°C using an Erichsen coater operating at a speed of 5 mm / min. The membrane film was allowed to stand for 30 seconds and then immersed in a water bath at 25°C for 10 minutes.

[0342] After the membrane has been detached from the glass plate, it is carefully transferred to a water bath for 12 h. The membrane is then transferred to a bath containing 2000 ppm NaOCl at 50°C for 4,5 h to remove PVP. After this process, the membrane is washed with water at 60°C and once with a 0.5 wt.-% sodium bisulfite solution to remove active chlorine. After several washing steps with water, the membrane is stored in a wet state until the characterization begins.

[0343] A flat sheet continuous membrane with microstructural features of a UF membrane of at least 10 x 15 cm size was obtained. The membrane had a top thin skin layer (1 to 10 microns) and a porous layer underneath (thickness: 100 to 150 microns). The results are given in Table 2.

[0344] Diaphragm Characterization

[0345] The pure water permeability (PWP) of the membrane was tested using a pressure cell with a 60 mm diameter using ultrapure water (saline-free, filtered through a Millipore UF system). In subsequent tests, solutions of different PEG standards were filtered at a pressure of 0.15 bar. The molecular weight cut-off was determined by GPC measurements of the feed and permeate.

[0346] The contact angle (CA) relative to water was measured as described above.

[0347] The molecular weight cutoff (MWCO) was determined as described above.

[0348] Table 2 :

[0349]

[0350]

[0351] The membranes obtained by the process of the present invention show higher water permeability and lower CA at comparable separation performance to the reference membranes, which means that they have improved hydrophilicity.

Claims

1. A method for preparing a membrane (M) containing a sulfonated polyarylene sulfone polymer (sP) and at least one further polymer (fP), the method comprising the following steps i) Conversion of the reaction mixture (R G ), the reaction mixture comprising An aromatic dihalogen sulfone component (component (A)), the aromatic dihalogen sulfone component comprising at least one sulfonated aromatic dihalogen sulfone (component (A1)) and at least one non-sulfonated aromatic dihalogen sulfone (component (A2)), at least one aromatic dihydroxy compound (component (B)), at least one carbonate compound (component (C)), and at least one aprotic polar solvent (component (D)), To obtain a product mixture (P) comprising the sulfonated polyarylene sulfone polymer (sP), the at least one aprotic polar solvent and the at least one inorganic halide compound G ), ii) from the product mixture (P G ) to obtain a first solution (S1) comprising the sulfonated polyarylene sulfone polymer (sP) and the at least one aprotic polar solvent, iii) mixing at least one further polymer (fP) with said 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 said membrane (M) comprising said sulfonated polyarylene sulfone polymer (sP) and said at least one further polymer (fP), wherein in step iii), additionally at least one pore former (pA) is mixed with the first solution (S1) to obtain the second solution (S2), and wherein the at least one additional polymer (fP) is at least one polyarylene sulfone polymer which may be sulfonated or non-sulfonated, and wherein the sulfonated polyarylene sulfone polymer (sP) and the at least one additional polymer (fP) are different from each other.

2. The method according to claim 1, wherein component (A1) comprises at least one compound selected from the group consisting of 4,4′-dichlorodiphenyl sulfone-3,3′-disulfonic acid, 4,4′-dichlorodiphenyl sulfone-3,3′-disulfonic acid disodium salt, 4,4′-dichlorodiphenyl sulfone-3,3′-disulfonic acid dipotassium salt, 4,4′-difluorodiphenyl sulfone-3,3′-disulfonic acid, 4,4′-difluorodiphenyl sulfone-3,3′-disulfonic acid disodium salt and 4,4′-difluorodiphenyl sulfone-3,3′-disulfonic acid dipotassium salt.

3. The method according to claim 1 or 2, wherein based on the reaction mixture (R G ) in the total weight of component (A2), component (A2) comprising not less than 80 wt% of at least one aromatic dihalogen sulfone selected from the group consisting of 4,4′-dichlorodiphenyl sulfone and 4,4′-difluorodiphenyl sulfone.

4. The method according to any one of claims 1 to 3, wherein based on the reaction mixture (R G ) in the total weight of component (B), component (B) contains not less than 80 wt% of 4,4'-dihydroxybiphenyl.

5. The method according to any one of claims 1 to 4, wherein based on the reaction mixture (R G ) in the total weight of component (C), component (C) containing not less than 50wt% of potassium carbonate.

6. The method according to any one of claims 1 to 5, wherein based on the reaction mixture (R G ) in the total weight of component (D), component (D) comprising not less than 50 wt % of at least one solvent selected from the group consisting of: N-methylpyrrolidone, N-dimethylacetamide, dimethyl sulfoxide and dimethyl-formamide.

7. The method according to any one of claims 1 to 6, wherein based on the reaction mixture (R G ) in an amount of 2 to 70 mol.-% of component (A1) and 30 to 98 mol.-% of component (A2).

8. The method according to any one of claims 1 to 7, wherein step iv) comprises the following steps iv-1) casting the second solution (S2) provided in step iii) to obtain a film of the second solution (S2), iii-2) separating the at least one aprotic polar solvent from the membrane of the second solution (S2) obtained in step iv-1) to obtain the membrane (M) in the form of a membrane.

9. The method according to any one of claims 1 to 8, wherein step iv) comprises the following steps iv-1) casting the second solution (S2) provided in step iii) to obtain a film of the second solution (S2), iii-2) immersing the membrane of the second solution (S2) obtained in step iv-1) in at least one protic solvent to obtain the membrane (M) in the form of a membrane.

10. A membrane (M) obtainable by the method according to any one of claims 1 to 9.

11. The membrane (M) according to claim 10, comprising 1% to 99.5% by weight of the sulfonated polyarylene sulfone polymer (sP) and 0.5% to 99% by weight of the at least one further polymer (fP), in each case based on the total weight of the membrane (M).

12. Device for ultrafiltration, comprising a membrane (M) according to claim 10 or 11.

13. Use of the membrane (M) according to claim 10 or 11 for ultrafiltration.

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