membrane

Abstract

An anion exchange membrane obtainable by curing a curable composition, the curable composition comprising a component (a) comprising a compound (A) and / or a compound (B) and / or a compound (C); wherein (A) is independently a 4-, 5-, 6-, or 7-membered non-aromatic bicyclic structure containing two optionally substituted nitrogen atoms; each of the rings contains a nitrogen atom which may be a bridgehead position; each of the nitrogen atoms is optionally substituted with hydrogen, C 1~3 Alkyl, C 5~6 (B) has one or two groups independently selected from cycloalkyl and vinylbenzyl attached thereto, provided that the compound contains at least two vinylbenzyl groups; (B) has one optionally substituted nitrogen atom and a C containing a nitrogen atom as a substituent to the ring. 1~6 and a 5-, 6-, or 7-membered non-aromatic heterocycle containing an alkyl group; and a nitrogen atom of the non-aromatic heterocycle is hydrogen, C 1~3 Alkyl, C 5~6 (C) is an optionally substituted, independently 4-, 5-, or 6-membered non-aromatic spirocyclic ring structure containing two nitrogen atoms; each of said rings contains at least one nitrogen atom which may be a bridgehead position; each of said nitrogen atoms is bonded to a hydrogen atom, C 1~3 Alkyl, C 5~6 The membrane of any of the preceding claims, wherein the compound has attached thereto one or two groups independently selected from cycloalkyl and vinylbenzyl, with the proviso that the compound contains at least two vinylbenzyl groups.

Description

[Technical Field]

[0001] The present invention relates to ion exchange membranes, in particular anion exchange membranes (AEMs), their preparation process and their use. [Background technology]

[0002] Ion exchange membranes are used in electrodialysis, electrolysis, acid and base production, and many other processes. Typically, the transport of ions through the membrane occurs under the influence of a driving force, such as a potential gradient.

[0003] Some ion exchange membranes include a porous support, which provides mechanical strength. Such membranes are often called "composite membranes" because of the presence of both an ionic-charged polymer that discriminates between oppositely charged ions and a porous support that provides mechanical strength.

[0004] BPM is commonly used to generate acids and bases, for example in a process called bipolar electrodialysis (BPED). BPM has both a cationic or anion exchange layer (AEL) and an anionic or cation exchange layer (CEL), and therefore has both negatively and positively charged layers.

[0005] In the BPED process, acids and bases are generated at the boundary of the BPM by the water dissociation reaction (WDR). + and OH -The ions pass through the corresponding ion exchange layers toward the cathode and anode, respectively. The BPED process is carried out in a bipolar electrodialysis stack, which contains monopolar anion exchange and monopolar cation exchange membranes in addition to a bipolar membrane. In a bipolar electrodialysis stack, the monopolar cation and anion exchange membranes are responsible for selectively separating salt ions in the feed stream according to their charge. The salt anions then combine with H+ formed by the WDR to form acids, and the salt cations combine with OH- to form bases. For example, if NaCl is used in the feed stream, the monopolar membrane will separate Cl - From Na + By separating the two, NaOH and HCl are formed.

[0006] To generate high concentrations of acids and bases, it is important that the monopolar membrane has very high pH stability and durability (high pH stability and durability result in a long membrane life). High efficiency of the process for generating acids and bases is also desirable. This is due to the H + and OH - To prevent ions from reaching the wrong channel and recombining, leading to product loss, the membrane needs to have very high permselectivity. Especially for anion-exchange membranes, it is difficult to achieve high proton blocking capacity at high concentrations due to the small size of protons.

[0007] WO2020 / 058665 describes porous cationic membranes for detecting, filtering and / or purifying biomolecules. [Prior art documents] [Non-patent literature]

[0008] [Non-Patent Document 1] WO2020 / 058665 Summary of the Invention [Problem to be solved by the invention]

[0009] It is an object of the present invention to provide an anion exchange membrane that is mechanically strong, has high stability at very low pH values, and has high permselectivity at high acid concentrations. [Means for solving the problem]

[0010] According to a first aspect of the present invention, there is provided an anion exchange membrane obtainable by curing a curable composition, the curable composition comprising a component (a) including a compound (A) and / or a compound (B) and / or a compound (C); (A) is an optionally substituted non-aromatic bicyclic structure containing two nitrogen atoms; the rings of said non-aromatic bicyclic structure are independently 4-, 5-, 6-, or 7-membered; each of said rings comprises a nitrogen atom, which may be at a bridgehead position; Each of the nitrogen atoms may be hydrogen, C 1~3 Alkyl, C 5~6 has attached thereto one or two groups independently selected from cycloalkyl, and vinylbenzyl, provided that the compound contains at least two vinylbenzyl groups; (B) is an optionally substituted C ring containing one nitrogen atom and a nitrogen atom as a substituent to the ring. 1~6 and a 5-, 6-, or 7-membered non-aromatic heterocycle containing an alkyl group; The nitrogen atom of the non-aromatic heterocycle may be substituted with hydrogen, C 1~3 Alkyl, C 5~6 has attached thereto one or two groups independently selected from cycloalkyl, and vinylbenzyl, provided that the compound contains at least two vinylbenzyl groups; (C) is an optionally substituted non-aromatic spirocyclic structure containing two nitrogen atoms; the rings of said non-aromatic spirocyclic structure are independently 4-, 5-, or 6-membered; each of said rings contains at least one nitrogen atom, which may be in a bridgehead position; Each of the nitrogen atoms may be hydrogen, C 1~3 Alkyl, C 5~6 The anion exchange membrane is provided as described above, wherein the compound has one or two groups independently selected from cycloalkyl and vinylbenzyl attached thereto, with the proviso that the compound contains at least two vinylbenzyl groups.

[0011] In this document (including the claims), the verb "comprise" and its conjugations are used in their open-ended sense, meaning that the items following the term are included, but not the exclusion of items not specifically mentioned. Additionally, a reference to an element by the indefinite article "a" or "an" does not exclude the possibility that more than one of the elements is present, unless the context clearly requires that one or only one element be present. Thus, the indefinite article "a" or "an" typically means "at least one." Component (a) of the curable composition may contain more than one compound selected from compound (A), compound (B), and / or compound (C). When component (a) is mentioned, it refers to all compounds that form part of component (a). "Optionally substituted" means that the compound contains optional substituents. A vinylbenzyl group is a CH═CHC₆H₄CH₂*— group, where the asterisk denotes the point of attachment to the rest of the molecule.

[0012] The optional substituents in compounds (A), (B) and (C) are preferably C 1~3 It is alkyl. Component (a) of the curable composition has the function of a crosslinker. Preferably, the molar fraction of component (a) relative to all the curable components of the curable composition is at least 0.90.

[0013] Preferably, at least one of the nitrogen (N) atoms in component (a) is a quaternary compound, more preferably at least two of the nitrogen atoms are quaternary compounds. When more than one compound is present in component (a), preferably all compounds in component (a) contain at least one quaternary nitrogen atom, more preferably at least two of the nitrogen atoms are quaternary compounds. The nitrogen atom is non-aromatic, i.e., not part of an aromatic heterocycle. Preferably, the ratio of N to vinylbenzyl groups in the quaternary compound is at least 1:3, more preferably at least 1:2, for example, 1:2 or 2:3. Preferably, the ratio of N to vinylbenzyl groups in the quaternary compound is at most 2:1, more preferably at most 3:2, for example, 1:1. In one embodiment, component (a) contains two nitrogen atoms and two vinylbenzyl groups.

[0014] Component (a) (i.e., each of the compounds forming part of component (a)) preferably has a molecular weight of less than 700 Da, more preferably less than 600 Da, and especially less than 550 Da. By keeping the molecular weight of compound (a) low, the ion exchange capacity of the AEM of the present invention is suitable for most applications.

[0015] Examples of compounds that can be used as component (a) include the following compounds AXL3-1 to AXL3-23.

[0016] [ka]

[0017] [ka]

[0018] [ka]

[0019] [ka]

[0020] [ka]

[0021] [ka]

[0022] The curable composition preferably comprises 65 to 85 wt % of component (a), more preferably 65 to 75 wt % of component (a), and in one embodiment, 70 to 75 wt % of component (a). In one embodiment, the anion exchange membrane according to the first aspect of the present invention comprises at least 1 ppm of monomer (a) (typically as a result of incomplete curing when the membrane is formed), preferably at least 10 ppm, particularly at least 100 ppm of monomer (a). Preferably, the anion exchange membrane comprises less than 20,000 ppm of component (a), more preferably less than 10,000 ppm of component (a). Component (a) refers to the sum of all compounds forming component (a).

[0023] The curable composition optionally further comprises, as component (b), a monomer comprising a group having a cationic charge and one or only one curable ethylenically unsaturated group. Preferably, the curable composition does not comprise component (b), or the curable composition comprises a small amount of component (b), for example, the curable composition preferably comprises 0 to 10 wt % of component (b), more preferably 0 to 7 wt % of component (b).

[0024] Component (b) may comprise one or more monomers containing a group bearing a cationic charge and one or only one curable ethylenically unsaturated group. In component (b), the group having a cationic charge is preferably a quaternary ammonium group. The one and only curable ethylenically unsaturated group present in component (b) is preferably a vinyl or allyl group, more preferably a vinyl group.

[0025] In one embodiment, component (b) has the formula (SM), where R 1 , R 2 and R 3 each independently represents an alkyl group or an aryl group, or R 1 , R 2 and R 3 two or three of these, together with the positively charged nitrogen atom to which they are attached, form an optionally substituted 5- or 6-membered ring; n3 represents an integer of 1 to 3; X3 Θ represents an anion, preferably a chloride ion, a bromide ion, an iodide ion or a hydroxide ion.

[0026] [ka]

[0027] Examples of component (b) of formula (SM) include the following compounds:

[0028] [ka]

[0029] The above components can be prepared, for example, as described in US2016 / 177006. The curable composition optionally further comprises, as component (c), a radical initiator. Preferred radical initiators include thermal initiators, photoinitiators, and combinations thereof.

[0030] The curable composition preferably comprises 0 to 10 wt % of a radical initiator, more preferably 0 to 3 wt % of a radical initiator. If the curable composition is to be cured using ultraviolet light, visible light, or thermally, the curable composition preferably comprises 0.001 to 2 wt %, especially 0.005 to 1.5 wt %, of a radical initiator.

[0031] Examples of suitable thermal initiators that can be used as component (c) include 2,2'-azobis(2-methylpropionitrile) (AIBN), 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), nitrile), dimethyl 2,2'-azobis(2-methylpropionate), 2,2'-azobis[N-(2-propenyl)-2-methylpropionamide, 1-[(1-cyano-1-methylethyl)azo]formamide, 2,2'-azobis(N-butyl-2-methylpropionamide), 2,2'-azobis(N-cyclohexyl-2-methylpropionamide), 2,2'-azobis(2-methylpropionamide) 2,2'-Azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride, 2,2'-Azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride, 2,2'-Azobis[2-(2-imidazolin-2-yl)propane]disulfate dihydrate, 2,2'-Azobis[N-(2-carboxyethyl)-2-methylpropionamidine]hydrate, 2,2'-Azobis{2-[1-(2-hydroxyethyl)-2-imidazolin-2-yl]propane}dihydrate Examples of suitable azobis include 2,2'-azobis[2-(2-imidazolin-2-yl)propane], 2,2'-azobis(1-imino-1-pyrrolidino-2-ethylpropane) dihydrochloride, 2,2'-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide}, and 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide].

[0032] Examples of suitable photoinitiators that may be included as component (c) in the curable composition include aromatic ketones, acylphosphine compounds, aromatic onium salt compounds, organic peroxides, thio compounds, hexaarylbiimidazole compounds, ketoxime ester compounds, boric acid compounds, azinium compounds, metallocene compounds, active ester compounds, compounds having a carbon-halogen bond, and alkylamine compounds. Preferred examples of aromatic ketones, acylphosphine oxide compounds, and thio compounds include compounds having a benzophenone skeleton or thioxanthone skeleton described in "RADIATION CURING IN POLYMER SCIENCE AND TECHNOLOGY," pp. 77-117 (1993).More preferred examples thereof include alpha-thiobenzophenone compounds described in JP1972-6416B (JP 47-006416), benzoin ether compounds described in JP1972-3981B (JP 47-003981), alpha-substituted benzoin compounds described in JP1972-22326B (JP 47-022326), and alpha-substituted benzoin compounds described in JP1972-23664B (JP 47-022326). benzoin derivatives described in JP1982-30704A (JP 57-030704 A), aroylphosphonic acid esters described in JP1982-30704A (JP 57-030704 B), dialkoxybenzophenones described in JP1985-26483B (JP 60-026483 B), and benzoin derivatives described in JP1985-26403B (JP 60-026403 B) and JP1987-81345A (JP 62-081345 B). Benzoin ethers, alpha-aminobenzophenones described in JP1989-34242B (JP-B 01-034242), US4,318,791A, and EP0284561A1, p-di(dimethylaminobenzoyl)benzene described in JP1990-211452A (JP-A 02-211452), thio-substituted benzoin ethers described in JP1986-194062A (JP-A 61-194062), and the like. Examples of suitable initiators include substituted aromatic ketones, acylphosphine sulfides described in JP1990-9597B (JP Patent Publication No. 02-009597), acylphosphines described in JP1990-9596B (JP Patent Publication No. 02-009596), thioxanthones described in JP1988-61950B (JP Patent Publication No. 63-061950), and coumarins described in JP1984-42864B (JP Patent Publication No. 59-042864). In addition, photoinitiators described in JP2008-105379A and JP2009-114290A are also preferred. In addition, photoinitiators described in "Ultraviolet Curing System" by Kato Kiyomi, pages 65-148 (published by Research Center Co., Ltd. in 1989) can also be used.

[0033] Particularly preferred photoinitiators include Norrish Type II photoinitiators having an absorption maximum at a wavelength greater than 380 nm when measured in one or more of water, ethanol, and toluene at a temperature of 23° C. Examples include photoinitiators derived from xanthenes, flavins, curcumins, porphyrins, anthraquinones, phenoxazines, camphorquinones, phenazines, acridines, phenothiazines, xantithones, thioxantithones, thioxanthenes, acridones, flavones, coumarins, fluorenones, quinolines, quinolones, naphthoquinones, quinolinones, arylmethanes, azos, benzophenones, carotenoids, cyanines, phthalocyanines, dipyrrines, squarines, stilbenes, styryls, triazines, or anthocyanins.

[0034] Optionally, the curable composition further comprises a monomer that does not contain a group with a cationic charge, and preferably further comprises a monomer that contains at least two curable ethylenically unsaturated groups as component (d).

[0035] Preferably, the curable composition contains 0 to 5 wt % of component (d), and more preferably, the curable composition does not contain component (d). The curable composition preferably further comprises a solvent as component (e). The solvent is preferably an inert solvent. The inert solvent does not react with any of the other components of the curable composition. In a preferred embodiment, component (e) comprises water and optionally an organic solvent, particularly when some or all of the organic solvent is water-miscible. Water is useful for dissolving components (a) and (b), and optionally also component (c), and the organic solvent is also useful for dissolving any organic components present in the curable composition.

[0036] Component (e) is useful for reducing the viscosity and / or surface tension of the curable composition. In a preferred embodiment, the curable composition comprises 10 to 40 wt %, preferably 20 to 29 wt %, and especially 20 to 26 wt % of component (e).

[0037] Examples of inert solvents that can be used as or in component (e) include water, alcohol-based solvents, ether-based solvents, amide-based solvents, ketone-based solvents, sulfoxide-based solvents, sulfone-based solvents, nitrile-based solvents, and organophosphorus-based solvents. Examples of alcohol-based solvents that can be used as or in component (e) (especially in combination with water) include methanol, ethanol, isopropanol, n-propanol, n-butanol, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, and mixtures containing two or more thereof. Additionally, preferred inert organic solvents that can be used in component (e) include dimethyl sulfoxide, dimethylimidazolidinone, sulfolane, N-methylpyrrolidone, dimethylformamide, acetonitrile, acetone, 1,4-dioxane, 1,3-dioxolane, tetramethylurea, hexamethylphosphoramide, hexamethylphosphorotriamide, pyridine, propionitrile, butanone, cyclohexanone, tetrahydrofuran, tetrahydropyran, 2-methyltetrahydrofuran, ethylene glycol diacetate, cyclopentyl methyl ether, methyl ethyl ketone, ethyl acetate, y-butyrolactone, and mixtures containing two or more thereof.

[0038] The curable composition may further comprise other ingredients such as inhibitors, wetting agents to improve coating properties, biocides, stabilizers, preferably in small amounts, for example 0-3 wt %.

[0039] The AEM preferably has a low water permeability so that (hydrate) ions can pass through the membrane, but (free) water molecules do not easily pass through the membrane. The water permeability of the AEM is preferably 1.10 -11 m 3 / m 2 Lower than s kPa, preferably 5.10 -12 m 3 / m 2 Lower than s kPa, especially 4.10 -12 m3 / m 2 Lower than ·s·kPa.

[0040] The molar fraction of component (a) (all compounds in component (a)) relative to all curable compounds present in the curable composition is preferably at least 0.91, more preferably at least 0.95. A high ratio of component (a) relative to all curable compounds present in the curable composition is preferred to obtain a membrane with a high crosslink density and therefore a high permselectivity.

[0041] The permselectivity (PS) of the membranes of the invention for protons, as determined as described below (in a 0.05M to 4M HCl system), is preferably at least 50%, more preferably at least 60%.

[0042] The electrical resistance (ER) of the membrane of the present invention is preferably 25 ohms / cm when component (a) contains only one quaternary nitrogen atom. 2 less than, more preferably 20 ohms / cm 2 The ER of the membrane of the present invention is preferably less than 15 ohm / cm when component (a) contains at least two quaternary nitrogen atoms. 2 The ER can be determined (in 2M NaCl) as described below.

[0043] The mole fraction of component (a) relative to all curable compounds present in the curable composition is preferably at most 1.0. The molar fraction of component (a) relative to all curable compounds present in the curable composition can be calculated by dividing the molar amount of component (a) by the sum of the molar amounts of all curable compounds present in the curable composition. Alternatively, the molar fraction can be determined by measuring the extractables from an anion exchange membrane, as described, for example, on page 19 of WO 2022 / 162083.

[0044] The distance between two nitrogen atoms in component (a) (compound of component (a)) is preferably at least 0.35 nm, which enhances the pH stability of the resulting membrane. Preferably, the distance between two nitrogen atoms in component (a) is less than 1.5 nm, which enhances the crosslink density of the resulting membrane. Preferably, the nitrogen atoms have a cationic charge, which makes the anion exchange membrane suitable over the entire pH range. If the nitrogen atoms in component (a) do not have a cationic charge, the resulting anion exchange membrane can only be used in an acidic environment.

[0045] Preferably, the ion exchange capacity (IEC) of the anion exchange membrane of the present invention is at least 0.55 meq / g dry membrane, more preferably at least 0.65 meq / g dry membrane, when component (a) contains only one quaternary nitrogen atom. Preferably, the IEC of the anion exchange membrane of the present invention is at least 1.15 meq / g dry membrane, more preferably at least 1.44 meq / g dry membrane, when component (a) contains at least two quaternary nitrogen atoms. Such an IEC can provide an anion exchange membrane with low electrical resistance. The IEC may be measured by the method described below.

[0046] Preferably, the anion exchange membrane according to the present invention has an IEC of less than 1.85 meq / g dry membrane as measured by the method described below. Such an IEC can provide an anion exchange membrane that does not swell excessively and therefore retains excellent permselectivity during use.

[0047] The anion exchange membrane of the present invention preferably further comprises a porous support. Examples of usable porous supports include woven and nonwoven synthetic fabrics and extruded films. Examples include wet-laid and dry-laid nonwoven materials, spunbond and meltblown fabrics, and nanofiber webs made from, for example, polyethylene, polypropylene, polyacrylonitrile, polyvinyl chloride, polyphenylene sulfide, polyester, polyamide, polyaryletherketone, such as polyetheretherketone, and copolymers thereof. The porous support can also be a porous membrane, such as polysulfone, polyethersulfone, polyphenylene sulfone, polyphenylene sulfide, polyimide, polyetherimide, polyamide, polyamideimide, polyacrylonitrile, polycarbonate, polyacrylate, cellulose acetate, polypropylene, poly(4-methyl-1-pentene), polyvinylidene fluoride, polytetrafluoroethylene, polyhexafluoropropylene, and polychlorotrifluoroethylene membranes, and their derivatives.

[0048] The porous support preferably has an average thickness of 10 to 800 μm, more preferably 15 to 300 μm, especially 20 to 150 μm, and even more especially 30 to 130 μm, for example about 60 μm or about 100 μm.

[0049] The porous support preferably has a porosity of 30-95%, more preferably 40-60%, in which case (in the final membrane) the pores are filled with the anion exchange polymer obtained by curing the composition, i.e., the membrane preferably comprises 40-60 vol.% porous (unfilled) support material and 60-40 vol.% anion exchange polymer material (i.e., the composition cured according to the first aspect of the present invention). These porosities provide an excellent balance between low electrical resistance and excellent permselectivity. The free volume of the porous support can be determined by its thickness and weight (g / m) prior to fabrication of the membrane. 2 ) and fiber density (g / m 3 ) data can be calculated.

[0050] If present, the porous support may be treated to modify its surface energy, for example to a value greater than 45 mN / m, preferably greater than 55 mN / m. Suitable treatments include corona discharge treatment, plasma glow discharge treatment, flame treatment, ultraviolet light irradiation treatment, chemical treatment, etc., for the purposes of improving the wettability of the porous support and the adhesion of the porous support to the anion exchange membrane.

[0051] Commercially available porous supports are available from a variety of sources, such as Freudenberg Filtration Technologies (Novatexx materials), Lydall Performance Materials, Celgard LLC, APorous Inc., SWM (Conwed Plastics, DelStar Technologies), Teijin, Hirose, Mitsubishi Paper Mills Ltd, and Sefar AG.

[0052] Preferably, the porous support is a porous polymeric support. Preferably, the porous support is a woven or nonwoven synthetic fabric or an extruded film that does not have covalently attached ionic groups.

[0053] The anion exchange membrane of the present invention preferably has an average thickness of 15 μm to 600 μm, more preferably 50 μm to 450 μm, and particularly preferably 60 to 240 μm. According to a second aspect of the present invention, there is provided a process for preparing an anion exchange membrane, the process comprising curing a curable composition as defined (and preferably as defined) in relation to the first aspect of the present invention.

[0054] The process according to the second aspect of the present invention preferably comprises: i. providing a porous support; ii. impregnating a porous support with a curable composition; and iii. Curing the curable composition and the curable composition is as defined above.

[0055] The curable composition can be cured by any suitable process, examples of which include thermal curing, photocuring, electron beam (EB) irradiation, gamma irradiation, and combinations of the foregoing.

[0056] Preferably, the process according to the second aspect of the present invention comprises a first curing step and a second curing step (dual curing). Dual curing is preferred because it increases the crosslink density of the resulting anion exchange membrane, which in turn improves the permselectivity.

[0057] In a preferred embodiment of the process according to the second aspect of the present invention, the curable composition is first cured by photocuring, for example by irradiating the curable composition with ultraviolet (UV) or visible light, or by gamma or electron beam radiation, thereby polymerizing the curable components present in the curable composition, and then by applying a second curing step. The second curing step preferably involves thermal curing, gamma irradiation, or EB irradiation of the product of the first curing step, and therefore preferably applies a different curing technique than the first curing step. If gamma or electron beam irradiation is used in the first curing step, a dose of 60 to 200 kGy, more preferably 80 to 150 kGy, is applied to the curable composition.

[0058] In one embodiment, the process according to the second aspect of the present invention comprises curing a curable composition to form an anion exchange membrane in a first curing step, winding the anion exchange membrane onto a core (optionally with an inert polymer foil), and then carrying out a second curing step on the wound product of the first curing step.

[0059] In a preferred embodiment, the first and second curing steps are each selected from: (i) UV curing (first curing step) followed by thermal curing (second curing step); (ii) UV curing followed by electron beam curing; and (iii) electron beam curing followed by thermal curing.

[0060] Component (c) may contain only one radical initiator or more than one radical initiator, for example a mixture of several photoinitiators (e.g., for a single cure) or a mixture of a photoinitiator and a thermal initiator (e.g., for a dual cure).

[0061] In one embodiment, the second curing step is carried out using gamma or electron beam (EB) irradiation. For the second curing step by gamma or EB irradiation, preferably a dose of 60 to 200 kGy is applied to the product of the first curing step, more preferably a dose of 80 to 150 kGy.

[0062] For the optional second curing step, heat curing is preferred. Heat curing is preferably carried out at a temperature of 50-100°C, more preferably 60-90°C. Heat curing is preferably carried out for 2-72 hours, e.g., about 3 hours for sheets, and 8-16 hours, e.g., about 10 hours for small rolls, and 24-72 hours for large rolls. Optionally, after the first curing step, a polymer foil is applied to the product of the first curing step before winding it onto a spool (this reduces oxygen inhibition, drying, and / or stacking of the product of the first curing step onto itself).

[0063] In a preferred process according to the second aspect of the present invention, the curable composition is continuously applied to a moving (preferably porous) substrate, preferably by a manufacturing unit comprising a curable composition application station, one or more irradiation sources for curing the curable composition, a film collection station, and means for moving the substrate from the curable composition application station to the irradiation sources and further to the film collection station.

[0064] The curable composition application station may be located at an upstream position relative to the irradiation source, which is located at an upstream position relative to the film collection station. Examples of coating techniques suitable for applying the curable composition to a substrate include slot die coating, slide coating, air knife coating, roller coating, screen printing, and immersion. Depending on the technique used and the desired final specifications, it may be desirable to remove excess coating from the substrate, for example, by roll-to-roll squeeze, roll-to-blade or blade-to-roll squeeze, blade-to-blade squeeze, or removal using a coating bar. Photocuring is preferably performed for the first curing step, preferably at 40 to 20,000 mJ / cm. 2 The irradiation is typically done at a wavelength of 300 nm to 800 nm, using a dose of 1000 ppm. In some cases, additional drying may be required, in which case temperatures of 40° C. to 200° C. may be employed. If gamma or EB curing is used, irradiation may be done under low-oxygen conditions, e.g., less than 200 ppm oxygen.

[0065] According to a third aspect of the present invention there is provided the use (method of use) of an anion exchange membrane according to the first aspect of the present invention for use in an electromembrane process, for example for the treatment of polar liquids (e.g. desalination), the production of acids and bases, or the generation or storage of electricity.

[0066] According to a fourth aspect of the present invention there is provided an electrodialysis or electrodialysis reversal device, a bipolar electrodialysis device, an electrodeionization module, a flow-through capacitor, a diffusion dialysis apparatus, a membrane distillation module, an electrolyzer, a redox flow battery, an acid-base flow battery or a fuel cell comprising one or more anion exchange membranes according to the first aspect of the present invention. [Example]

[0067] The invention will now be illustrated by the following non-limiting examples in which all parts and percentages are by weight unless otherwise specified. pH stability The pH stability of anion exchange membranes was tested by soaking a sample of the membrane under test in 4 M HCl at 80°C for at least one month. After this treatment, the permselectivity (PS) of the membrane was measured and compared to its PS before soaking. If the PS after soaking was at least 80% of the original PS, the pH stability of the membrane was considered "OK"; if it was less than 80% of the original PS, the pH stability was considered poor ("NG").

[0068] Permselectivity (PS) The permselectivity (PS) (%) (i.e., the selectivity of an anion exchange membrane for the passage of ions of opposite charge) was measured as follows: The anion exchange membrane to be tested was placed in a two-compartment system: one compartment was filled with a 0.05 M solution of HCl and the other compartment was filled with a 4 M solution of HCl, the two compartments being separated by the membrane under test.

[0069] setting: The capillary, as well as the Ag / AgCl reference electrode (Metrohm type 6.0750.100), contained 3 M KCl; Effective membrane area is 9.62cm 2 was; · The distance between the capillaries was approximately 15 mm; · The measured temperature was 21.0±0.2℃; Cole Parmer Masterflex console drives (77521-47) with easy load II model 77200-62 gear pumps were used in two compartments; The flow rate was controlled at a constant 500 ml / min using a Porter Instrument flow meter (type 150AV-B250-4RVS) and a Cole-Parmer flow meter (type G-30217-90); Prior to the measurement, the anion exchange membrane samples were equilibrated in 0.25 M HCl solution for 1 hour. After 20 minutes, the voltage was read from a standard VOM (multimeter).

[0070] The PS was calculated from the voltage readings using the Nernst equation, and preferably the PS for HCl was at least 50%.

[0071] Ion Exchange Capacity (IEC) Prior to measurement, the membranes were converted to the chloride form by soaking the samples in 2 M NaCl solution for 1 hour. The 2 M NaCl solution was replaced once, and the samples were allowed to equilibrate for an additional 24 hours. The membrane samples were then rinsed with Milli-Q water, soaked in fresh Milli-Q water for 1 hour, and rinsed again with Milli-Q water.

[0072] A 2.0 cm diameter sample was punched out from the membrane sample with chloride counterion (12.57 cm 2 ), dried at 40°C for 24 hours, and weighed. The samples were then placed in 75 ml of Milli-Q® water for 24 hours to remove all non-counterions, followed by rinsing with Milli-Q® water. Each sample was then immersed in 10.00 ml of 0.1 M AgNO3 solution, and the solution was shaken with the sample for 24 hours. During shaking, AgCl salt precipitated, resulting in AgNO3. + - ions are Cl - As the -ions are removed, Cl - Ions are NO3 -The AgNO3 solution was completely exchanged with the ions. The samples were then removed from the AgNO3 solution and rinsed with a small amount of Milli-Q® water. The rinse water for each sample and the corresponding AgNO3 solution remaining after shaking the membrane sample were combined and titrated with a calibrated 0.1 M KBr solution, and the results were compared to the titration value of 10.00 ml of a blank solution of 0.1 M AgNO3 containing no membrane sample. The difference in titration results between the blank solution and each sample's test solution was correlated to the ion exchange capacity of the corresponding membrane using equation (I): IEC(meq / g dry film)=(YX)×0.1 / W Equation (I) where Y is the amount (in ml) of 0.1 M KBr used in the titration of the blank AgNO3 solution; X is the amount (in ml) of 0.1 M KBr used in titrating the AgNO3 solution in which the membrane sample was immersed, combined with the Milli-Q® water used to rinse the membrane sample after immersion in the AgNO3 solution; W is the dry weight of the membrane (in grams).

[0073] Porosity of the porous support The porosity of the porous support was calculated based on the thickness and weight (g / m) provided by the supplier. 2 ) and fiber density (g / m 3 ) calculated from the data.

[0074] Electrical Resistivity (ER) ER (ohm cm) of the anion exchange membranes prepared in the examples 2 ) was measured by the method described by Dlugolecki et al., J. of Membrane Science 319 (2008) pp. 217-218, with the following modifications: The auxiliary membranes were CMX and AMX from Tokuyama Soda Corporation, Japan; · The capillary, as well as the Ag / AgCl reference electrode (Metrohm type 6.0750.100) contained 3 M KCl; · The calibration liquid and the liquid in compartments 2, 3, 4 and 5 were 2.0 M NaCl solutions at 25°C; Effective membrane area is 9.62cm 2 was; · The distance between the capillaries was 5.0 mm; The measurement temperature was 25°C; · Cole-Parmer Masterflex console drives (77521-47) with Easyload II model 77200-62 gear pumps were used in all compartments; · The flow rate of each stream was 475 ml / min and was controlled by a Porter Instrument flow meter (type 150AV-B250-4RVS) and a Cole-Parmer flow meter (type G-30217-90); Prior to the measurements, the anion exchange membrane samples were equilibrated in a 0.5 M solution of NaCl at room temperature for at least 1 h. The ER is preferably low, e.g., 15 ohm cm 2 is less than.

[0075] Determination of the distance between nitrogen atoms in component (a) The distances between nitrogen atoms in each component (a) were determined by simulation using the open-source Avogadro software version 1.2.0 (Marcus D Hanwell, Donald E Curtis, David C Lonie, Tim Vandermeersch, Eva Zurek, and Geoffrey R Hutchison; see "Avogadro: An advanced semantic chemical editor, visualization, and analysis platform," Journal of Cheminformatics 2012, 4:17). The structure of each component (a) was drawn in the software, and the optimal chemical structure was determined using an automated optimization tool. The automated optimization tool was run with the following settings: - Force Field: UFF - Steps per update: 4 - Algorithm: Molecular Dynamics (300K) - Atoms were neither fixed nor ignored.

[0076] Once the automatic optimization tool was finished (dE=0), the distances between the nitrogen atoms were determined using the "click to measure" tool.

[0077] [Table 1]

[0078] Examples 1 to 6 are examples of working examples, and Comparative Examples 1 to 3 are comparative examples.

[0079] [Table 2]

[0080] Procedure for preparing AXL3-1 to AXL3-5 The corresponding diamine (1 mmol) and TEMPO-OH (0.01 mmol) were dissolved in chloroform (100 ml). Potassium carbonate (4 mmol) was suspended in the mixture, and iodomethane (2.1 mmol) was added dropwise. The mixture was stirred at room temperature for 3 hours. Water was added to the reaction, and the organic layer was separated and then washed with saturated ammonium chloride (2 × 150 ml). The organic layer was placed in a reflux flask, and 2.05 mmol of CMS-14 was added dropwise. The mixture was gently warmed to 40 °C and stirred overnight. Upon completion, the precipitated product was filtered off, and the solid was washed three times with diethyl ether. For AXL3-5, 2 mmol of potassium carbonate and 1.05 mmol of iodomethane were used instead of 4 mmol and 2.1 mmol, respectively. AXL3-1 to AXL3-5 were obtained as pale yellow solids.

[0081] CL-1 (used in Comparative Example 1) was synthesized as described in US2016 / 0177006.

[0082] [ka]

[0083] General Procedure for Preparing AXL-A and AXL-B of Comparative Examples 2 and 3

[0084] [ka]

[0085] To a 50% solution of the corresponding diamine (1 mmol) containing 4-OH-TEMPO (0.1 g) in ethyl acetate, CMS-14 (2.02 mmol) was added dropwise over 1 hour. The mixture was then vigorously stirred for 2 hours. The resulting precipitate was filtered, rinsed with additional ethyl acetate, and dried. The diammonium salt was isolated as a white solid. Table 2 below shows the structures of the crosslinkers prepared in this manner and their yields.

[0086] [Table 3]

[0087] [Table 4]

[0088] [Table 5]

[0089] In CL-1 and AXL-A, R a and R b One of each of the two is R c and R d The connection of each of the two positively charged nitrogen atoms to one another results in a smaller distance between the two positively charged nitrogen atoms, resulting in an unacceptable (poor) decrease in pH stability, which is undesirable.

[0090] AXL-B has an aromatic linking group L and has low pH stability. CL-1, AXL-A and AXL-B are crosslinkers that do not have the structure claimed for component (a).

[0091] Preparation of curable compositions and anion exchange membranes The curable compositions shown in Table 4 above were prepared by sequentially mixing the stated amounts of solids (in wt%) into a mixture of water and n-propanol at a temperature of 40° C. Each of the curable compositions listed in Table 4 was applied to a porous support (100 μm thick, 50 g / m2 with 50% porosity) using a 100 μm Meyer bar. 2 Anion exchange membranes according to the first aspect of the present invention and comparative examples were prepared by applying a curable composition onto a PP / PE porous support (of 1000 MPa) at room temperature (21°C), removing the excess using a 4 µm Meyer bar, and then curing the composition. UV curing was carried out by placing a sample of the support containing the curable composition on a conveyor equipped with a D bulb in a Light Hammer® 10 from Fusion UV Systems Inc. at 5 m / min and exposing the sample to UV light emitted from the D bulb at 50% power.

[0092] The UV-cured samples were placed in metallized bags filled with 60 μm polyethylene terephthalate (PET) foil (from Toray Industries, Inc.) without any treatment. The bags were evacuated and sealed. The bags containing the films were placed in a conventional oven, and the films were heat-cured at 90°C for 3 hours.

Claims

1. An anion exchange membrane obtainable by curing a curable composition, the curable composition comprising a component (a) including a compound (A) and / or a compound (B) and / or a compound (C); During the ceremony, (A) is an optionally substituted non-aromatic bicyclic structure containing two nitrogen atoms; the rings of said non-aromatic bicyclic structure are independently 4-, 5-, 6-, or 7-membered; each of said rings comprises a nitrogen atom, said nitrogen atom optionally being at a bridgehead position; Each of the nitrogen atoms may be selected from the group consisting of hydrogen, C １～３ Alkyl, C ５～６ has attached thereto one or two groups independently selected from cycloalkyl, and vinylbenzyl, provided that the compound contains at least two vinylbenzyl groups; (B) is a C ring containing one nitrogen atom and a nitrogen atom as a substituent to the ring, which may be optionally substituted. １～６ an alkyl group; and a 5-, 6-, or 7-membered non-aromatic heterocycle; The nitrogen atom of the non-aromatic heterocycle may be substituted with hydrogen, C １～３ Alkyl, C ５～６ has attached thereto one or two groups independently selected from cycloalkyl, and vinylbenzyl, provided that the compound contains at least two vinylbenzyl groups; (C) is an optionally substituted non-aromatic spiro ring structure containing two nitrogen atoms; the rings of said non-aromatic spirocyclic structure are independently 4-, 5-, or 6-membered; each of said rings contains at least one nitrogen atom, said nitrogen atom optionally being in a bridgehead position; Each of the nitrogen atoms may be selected from the group consisting of hydrogen, C １～３ Alkyl, C ５～６ The anion exchange membrane as defined above, wherein one or two groups independently selected from cycloalkyl and vinylbenzyl are bonded to the compound, with the proviso that the compound contains at least two vinylbenzyl groups.

2. 2. The anion exchange membrane of claim 1, wherein component (a) comprises at least one quaternary nitrogen atom.

3. 3. The anion exchange membrane according to claim 1, wherein component (a) contains at least two quaternary nitrogen atoms.

4. 4. The anion exchange membrane according to claim 1, wherein the distance between two nitrogen atoms in component (a) is at least 0.35 nm.

5. The optional substituents are C １～３ The anion exchange membrane according to any one of claims 1 to 4, wherein the anion exchange membrane is alkyl.

6. 6. The anion exchange membrane according to claim 1, wherein component (a) contains 2, 3 or 4 vinylbenzyl groups.

7. 7. The anion exchange membrane according to any one of claims 1 to 6, having an ion exchange capacity of at least 0.55 meq / g dry membrane and less than 1.85 meq / g dry membrane.

8. The anion exchange membrane according to any one of claims 1 to 7, wherein component (a) has a molecular weight of less than 700 Daltons.

9. The anion exchange membrane according to any one of claims 1 to 8, wherein the curable composition further comprises, as component (b), a monomer comprising a group having a cationic charge and one or only one curable ethylenically unsaturated group.

10. The anion exchange membrane according to any one of claims 1 to 9, wherein the curable composition further comprises, as component (c), a radical initiator.

11. The anion exchange membrane according to any one of claims 1 to 10, wherein the curable composition further comprises, as component (d), a monomer that does not contain a group having a cationic charge.

12. The anion exchange membrane according to any one of claims 1 to 11, wherein the curable composition further comprises a solvent as component (e).

13. The anion exchange membrane according to any one of claims 1 to 12, wherein the curable composition comprises 65 to 85 wt% of component (a), 0 to 10 wt% of component (b) a monomer comprising a group having a cationic charge and one or only one curable ethylenically unsaturated group, 0 to 10 wt% of component (c) a radical initiator, 0 to 5 wt% of component (d) a monomer not comprising a group having a cationic charge, and 10 to 40 wt% of component (e) a solvent.

14. The anion exchange membrane according to any one of claims 1 to 13, comprising at least 1 ppm of component (a).

15. A process for preparing an anion exchange membrane, comprising curing a curable composition as defined in any one of claims 1 to 14.

16. (i) providing a curable composition as defined in claim 1; (ii) applying the curable composition onto a porous support to impregnate the porous support with at least a portion of the curable composition; and (iii) curing the curable composition 16. The process of claim 15, comprising:

17. 15. An electrodialysis device, a bipolar electrodialysis device, an electrolyzer, a redox flow battery, an acid-base flow battery or a fuel cell comprising one or more anion exchange membranes according to any one of claims 1 to 14.

18. Use of an anion exchange membrane according to any one of claims 1 to 14 for the treatment of polar liquids, for the production of acids and bases, or for the generation or storage of electricity.

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