Membranes and their uses

Abstract

An ion exchange membrane obtainable by curing a composition comprising: (a) a curable monomer comprising at least one anionic or cationic group; (b) a photoinitiator having an absorption maximum at a wavelength longer than 380 nm, measured in one or more solvents selected from the group consisting of water, ethanol, and toluene, at a temperature of 23°C; (c) at least one coinitiator; and, optionally, (d) a curable monomer that does not comprise an anionic or cationic group; wherein at least one of the curable monomers present in the composition comprises an aromatic group.

Description

[Technical Field]

[0001] The present invention relates to ion exchange membranes and methods for their preparation and use. [Background technology]

[0002] Ion exchange membranes can be used in electrodialysis, electrodialysis reversal, electrolysis, diffusion dialysis, and several other processes. Typically, ion transport through a membrane occurs under the influence of a driving force such as an ion concentration gradient or an electric potential gradient.

[0003] Ion exchange membranes are generally classified as cation exchange membranes or anion exchange membranes depending on their predominant charge: Cation exchange membranes contain negatively charged groups that allow the passage of cations but reject anions, while anion exchange membranes contain positively charged groups that allow the passage of anions but reject cations.

[0004] Ion exchange membranes can be produced by polymerizing curable monomers using an energy source, such as electron beam (EB) irradiation, ultraviolet (UV) irradiation, or heat. Thermal curing is a thermal polymerization process and is generally very time-consuming. EB curing does not require an initiator and instead requires expensive equipment. UV curing is a fast and efficient process that requires high-power UV irradiation and a photoinitiator.

[0005] International Publication WO2017009602 ('602) describes the preparation of ion exchange membranes from simple aliphatic monomers using thermal and Type I photoinitiators. When the monomers used to prepare the ion exchange membrane are all aliphatic and / or simple aromatic monomers (e.g., as in '602), the UV curing step to form the ion exchange membrane is generally very effective. However, when one or more of the monomers used to prepare the ion exchange membrane significantly absorb in the UV region (e.g., below 380 nm or even longer wavelengths), the absorption of UV light by the monomer can significantly hinder the curing process. In such cases, very high doses of UV light and / or high concentrations of photoinitiator are required to achieve the formation of a sufficient number of radicals to obtain the desired polymerization rate. The use of high concentrations of photoinitiator is undesirable for several reasons. For example, it is more expensive to use a high concentration of photoinitiator than a low concentration. Membranes made from curable compositions containing high concentrations of photoinitiator(s) are often considered unsuitable for use in food and pharmaceutical applications due to potential toxicity and often require extra processing to reduce the possibility of unacceptable levels of photoinitiator leaching from the membrane into the food or pharmaceutical. Furthermore, high doses of UV radiation generate a lot of heat, which requires cooling and increases the risk of burning the film or any support or carrier present during the curing process, and is associated with high energy costs.

[0006] The ion exchange membrane may also include a porous support in addition to the ionic polymer. The porous support provides mechanical strength, and the pores present within the support contain a polymer derived from the curing of a curable composition containing an ionic monomer. A problem with porous supports derived from aromatic compounds is that they may absorb light intended to cure the ionic monomer present in the curable composition. This problem means that many porous supports derived from aromatic compounds are not suitable for preparing ion exchange membranes by UV curing.

[0007] To overcome the problem of porous supports derived from aromatic compounds absorbing the light required to cure the monomers, thermal curing methods have been used to prepare films containing such supports, however, thermal curing methods are generally time consuming. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] International Publication WO2017009602 Summary of the Invention

[0009] In view of the above, there is a need for a process for preparing ion exchange membranes from aromatic monomers that is rapid and avoids the need for large amounts of photoinitiators. Furthermore, it is desirable that the ion exchange membranes have good selectivity, low electrical resistance, and high robustness.

[0010] According to a first aspect of the present invention, (a) a curable monomer containing at least one anionic or cationic group; (b) a photoinitiator having an absorption maximum at a wavelength longer than 380 nm, measured at a temperature of 23° C. in one or more of water, ethanol, and toluene; (c) at least one coinitiator; and Optionally (d) a curable monomer free of anionic and cationic groups; wherein at least one of the curable monomers present in the composition comprises an aromatic group. DETAILED DESCRIPTION OF THE INVENTION

[0011] In this document (including the claims), the verb "comprise" and its conjugations are used in their open-ended sense to mean that items following the word are included, but items not specifically mentioned are not excluded. Furthermore, reference to an element by the indefinite article "a" or "an" does not exclude the possibility that more than one element is present, unless the context clearly requires that only one element be present. Thus, the indefinite article "a" or "an" typically means "at least one." The term "ion exchange membrane" is often abbreviated herein as "membrane."

[0012] The membranes of the present invention are preferably in the form of sheets or hollow fibers. Preferably, component (b) is a Norrish Type II photoinitiator. '602 describes the use of thermal and Type I photoinitiators, but does not describe the use of photoinitiators as defined in component (b) of the present invention.

[0013] The ion exchange membrane is preferably a cation exchange membrane (i.e., containing anionic groups, also known as CEM), an anion exchange membrane (i.e., containing cationic groups, also known as AEM), or a bipolar membrane (depending on its predominant charge). As mentioned above, cation exchange membranes contain negatively charged groups that allow the passage of cations but reject anions, while anion exchange membranes contain positively charged groups that allow the passage of anions but reject cations. Bipolar membranes typically contain a layer of cationic membrane adjacent to a layer of anionic membrane.

[0014] Preferred anionic group(s) that may be present in component (a) include acidic groups such as sulfo, carboxy and / or phosphato groups, especially sulfo groups.

[0015] Preferred cationic group(s) that may be present in component (a) include quaternary ammonium and phosphonium groups, especially quaternary ammonium groups. Preferably, component (a) is not a polymer but is a monomer or oligomer.

[0016] Preferably, component (a) has a molecular weight (MW) that satisfies the following formula: MW<(3000+300n) [In formula: MW is the molecular weight of component (a); n has a value of 1, 2, 3 or 4 and is the number of ionic groups present in component (a).

[0017] In the above formula, in some embodiments, MW is more preferably <(250+250n), even more preferably <(200+200n), and especially <(150+200n), where MW and n are as defined above.

[0018] Component (a) preferably contains an anionic or cationic group and one or more ethylenically unsaturated groups, e.g., polymerizable ethylenically unsaturated groups. Component (a) may contain several different compounds.

[0019] Depending on the pH of the composition, the anionic or cationic groups present in component (a) can partially or totally form salts with counterions, e.g., sodium, lithium, ammonium, potassium and / or pyridinium in the case of anionic groups, and chloride and / or bromide in the case of cationic groups.

[0020] Preferred ethylenically unsaturated groups which may be present in components (a) and (d), if present, are in the form of vinyl groups, e.g., (meth)acrylic groups, allyl groups or styrene groups. The (meth)acrylic groups are preferably (meth)acrylate or (meth)acrylamide groups, more preferably acrylic groups, e.g., acrylate or acrylamide groups.

[0021] In one embodiment, component (a) comprises a vinylaryl group, such as a vinylphenyl group, a vinylpyridyl group, a vinylimidazyl group, a vinylthiazinyl group, a vinyltriazinyl group, a vinylpyrryl group, and / or a vinylpyrimidyl group.

[0022] The curable monomer containing an ionic group is preferably component (a), but can also be component (d) or a further monomer present in the composition. The present invention is therefore also applicable to ionic monomers that do not contain aromatic groups.

[0023] Examples of curable monomers containing at least one anionic group include acrylic acid, beta-carboxyethyl acrylate, maleic acid, maleic anhydride, vinyl sulfonic acid, phosphonomethylated acrylamide, (2-carboxyethyl)acrylamide, 2-(meth)acrylamido-2-methylpropanesulfonic acid, styrenesulfonic acid, compounds according to formulas M-1 to M-35 shown below, and mixtures containing two or more thereof, in which the letter M represents two atoms selected from Na+ and Li+ and mixtures thereof:

[0024] [ka]

[0025] [ka]

[0026] [ka]

[0027] Preferred curable monomers containing at least one cationic group include quaternary ammonium groups. Examples of such monomers include (3-acrylamidopropyl)trimethylammonium chloride, 3-methacrylamidopropyltrimethylammonium chloride, (ar-vinylbenzyl)trimethylammonium chloride, (2-(methacryloyloxy)ethyl)trimethylammonium chloride, [3-(methacryloylamino)propyl]trimethylammonium chloride, (2-acrylamido-2-methylpropyl)trimethylammonium chloride, 3-acrylamido-3-methylbutyltrimethylammonium chloride, acryloylamino-2-hydroxypropyltrimethylammonium chloride, N-(2-aminoethyl)acrylamidotrimethylammonium chloride, quaternized vinylimidazole, compounds according to the following formulas M-36 to M-42, compounds according to formulas (CL) and (SM), and mixtures containing two or more of these.

[0028] [ka]

[0029] In formula (CL): L1 represents an alkylene group or an alkenylene group; R a , R b , R c , and R d are each independently optionally substituted alkyl or optionally substituted aryl; or R a and R b , and / or R c and R d is the NL shown in formula (CL) 1 - together with the N group to form a ring; n1 and n2 each independently have a value from 1 to 10; and X 1- and X2 - each independently represents an organic or inorganic anion. In formula (SM): R 1 , R 2 , and R 3 are each independently an optionally substituted alkyl or an optionally substituted aryl; or R 1 and R 2 , or R 1 , R 2 , and R 3 forms a ring together with the N atom shown in formula (SM); n3 has a value from 1 to 10; and X3 - represents an organic or inorganic anion.

[0030] The composition preferably comprises 2 to 95 wt. %, more preferably 20 to 95 wt. %, and especially 30 to 75 wt. % of component (a). In some embodiments, the composition preferably comprises 2 to 10 wt. %, more preferably 2 to 6 wt. %, for example 2 to 4 wt. % of component (a).

[0031] Component (a) optionally comprises one or more (eg, 2-5) curable monomers each having at least one anionic or cationic group. Preferably, component (a) has 1 to 5, more preferably 1 or 2, anionic or cationic groups.

[0032] The photoinitiator is preferably a Norrish type II photoinitiator. Typically, a Norrish type II photoinitiator is a compound that reaches an excited (triplet) state when irradiated with light of an appropriate wavelength and intensity, and transfers its energy to the coinitiator by abstracting an electron or a hydrogen atom, causing the coinitiator to form a reactive radical species. The reactivity (i.e., cure rate) of the Norrish type II photoinitiator can be evaluated using a Mettler Toledo DSC822e differential scanning calorimeter (DSC), as described in the experimental section below.

[0033] The photoinitiator preferably has an absorption maximum (i.e., at least one) at wavelengths between 385 and 800 nm, more preferably between 400 and 800 nm, e.g., between 430 and 800 nm, measured at 23°C in one or more of water, ethanol, and toluene. The absorption maximum is preferably measured at 23°C using a 0.01 wt% concentration of the photoinitiator dissolved in the relevant solvent (i.e., water, ethanol, or toluene) using, for example, a 1 mm path length (e.g., a quartz cuvette with an internal length of 1 mm through which light passes). For example, the absorption maximum can be measured using a Varian Cary 100 conc. double-beam UV / VIS spectrophotometer.

[0034] Most photoinitiators are soluble in at least one of water, ethanol, and toluene at a temperature of 23° C. However, if the photoinitiator is found not to be soluble in any of these, one or two drops of a better solvent (e.g., dimethyl sulfoxide) may be added to obtain a complete solution.

[0035] Many suitable photoinitiators useful as component (b) contain polar groups (e.g., amine, carbonyl, or hydroxyl groups) and are soluble in ethanol. Photoinitiators containing ionic groups typically exhibit good solubility in water. Photoinitiators containing fused aromatic rings generally exhibit low or no solubility in water and ethanol, but good solubility in toluene. For some photoinitiators, a mixture of solvents may be preferred. Thus, the absorption maximum of component (b) can be measured at 23°C, and a solvent selected from water, ethanol, toluene, and mixtures thereof in which component (b) is soluble is generally chosen.

[0036] The molar extinction coefficient at the absorption maximum (i.e., longer than 380 nm) of the photoinitiator (b) is preferably at least 7500 M -1 cm -1 (750m 2 mol -1 ), more preferably at least 10,000M -1 cm -1The molar extinction coefficient can be measured using a UV-VIS spectrophotometer, such as the Cary spectrophotometer from Agilent Technologies. TM The chromatographic data can be measured using a UV-visible spectrophotometer.

[0037] Component (b) may have an absorption maximum at a wavelength of 380 nm or less (in each case, when measured in one or more solvents selected from water, ethanol, and toluene at a temperature of 23°C), provided that it also has an absorption maximum at a wavelength longer than 380 nm.

[0038] The composition is such that the ratio of the extinction coefficient of the composition containing component (b) to the extinction coefficient of the same composition but excluding component (b), when measured at a wavelength at which component (b) has maximum absorption (or at a wavelength at which the radiation source has significant emission), is preferably greater than 1, more preferably greater than 1.5, and especially greater than 2. This ratio is an indication of the absorption capacity of component (b) in the composition itself and therefore forms a useful parameter for defining the properties of a preferred photoinitiator for component (b). If this ratio is equal to 1, other components in the composition will absorb most or all of the light intended to cause curing of the composition, which may negate the effectiveness of the photoinitiator.

[0039] Thus, the composition preferably satisfies Formula 1: (A1 / A2)>1.5 formula 1 [In formula: A1 is the extinction coefficient of the composition at wavelength X nm; A2 is the extinction coefficient at wavelength X nm of a composition identical to the composition except that component (b) is omitted; and X nm is the wavelength of the absorption maximum of component (b); All damping coefficients are measured at a temperature of 23°C].

[0040] Preferably, (A1 / A2)>2. In Equation 1, the attenuation coefficient is preferably measured at 23° C. using, for example, a 1 mm path length (eg, using a quartz cuvette with an internal length through which the light passes, of 1 mm).

[0041] Preferably, component (b) comprises a xanthene-, flavin-, curcumin-, porphyrin-, anthraquinone-, phenoxazine-, camphorquinone-, phenazine-, acridine-, phenothiazine-, xanthone-, thioxanthone-, thioxanthene-, acridone-, flavone-, coumarin-, fluorenone-, quinoline-, quinolone-, naphthaquinone-, quinolinone-, arylmethane-, azo-, benzophenone-, carotenoid-, cyanine-, phthalocyanine-, dipyrrin-, squarine-, stilbene-, styryl-, triazine-, or anthocyanin-derived photoinitiator, or a mixture comprising two or more thereof (e.g., 2 to 5 such photoinitiators), provided that the photoinitiator has an absorption maximum at a wavelength longer than 380 nm, in each case measured in one or more of water, ethanol, and toluene at a temperature of 23° C. More preferably, component (b) comprises a photoinitiator derived from xanthene, flavin, curcumin, porphyrin, anthraquinone, phenoxazine, phenazine, acridine, phenothiazine, thioxanthene, acridone, flavone, coumarin, fluorenone, quinoline, quinolone, naphthaquinone, quinolinone, arylmethane, azo, carotenoid, cyanine, phthalocyanine, dipyrrin, squarine, styryl, triazine or anthocyanin, provided that it has an absorption maximum at a wavelength longer than 380 nm, in each case measured in one or more of the following solvents at a temperature of 23° C.

[0042] Examples of photoinitiators having the absorption maxima specified above include eosin Y, eosin Y disodium salt, fluorescein, uranine, erythrosin B, rose bengal, phloxine B, 4,5-dibromofluorescein, rhodamine B, riboflavin, flavin mononucleotide, acriflavine, curcumin, resazurin, safranine O, phenosafranine, neutral red, acridine orange, acid blue 43, 1,4-diamino-anthraquinone, 1,4-dihydroxy-anthraquinone, bromamine acid sodium salt, carminic acid, ethyl violet, patent blue V, methyl orange, naphthol yellow S, methylene blue, indigo carmine, (4 -dimethylaminostyryl)methylpyridinium iodide, quinoline yellow, quinoline yellow WS, thionine acetate, beta-carotene, coumarin 6, coumarin 343, coumarin 153, zinc protoporphyrin IX, zinc tetraphenylporphyrin tetrasulfonate, zinc phthalocyanine, cyanidin chloride, sodium indomonocarbocyanine, resorufin, Nile red, pyronin Y, 9-fluorenonecarboxylic acid, 3-butoxy-5,7-diiodo-6-fluoroone, 3-hydroxy-2,4,5,7-tetraiodo-6-fluoroone, 2-chlorothioxanthone, and quercetin. Preferred photoinitiators include safranine-O, acridine orange, bromamic acid sodium salt, ethyl violet, methyl orange, curcumin, riboflavin, flavin mononucleotide, methylene blue, zinc phthalocyanine, tetraphenylsulfonic acid porphyrin, quinolone yellow WS, eosin Y, eosin Y disodium salt, erythrosin B, rose bengal, rhodamine B, phloxine B, and dibromofluorescein.

[0043] The photoinitiator used as component (b) preferably contains a conjugated system with at least 10 (more preferably at least 12) delocalized (π) electrons. A conjugated system is a connected p-orbital system with delocalized electrons in a molecule, generally with alternating single and multiple bonds. The conjugated system can be linear, cyclic (aromatic), or a combination of linear and cyclic (aromatic). Linear conjugated systems typically have high extinction coefficients but may have undesirable radical scavenging properties. Therefore, component (b) preferably contains an aromatic group, and optionally also contains one or more linear conjugated groups.

[0044] The wavelength at which a photoinitiator has its absorption maximum and its extinction coefficient are strongly influenced by the functional groups present in the photoinitiator, especially when they are directly attached to atoms that form part of a conjugated system. Groups that have a favorable effect on the extinction coefficient include, for example, primary, secondary, and tertiary amine groups, hydroxyl groups, ether groups, thioether groups, alkyl groups, and carbonyl groups. The photoinitiator preferably contains one or more of these groups. Halogens do not significantly affect the absorption characteristics of the photoinitiator, but they stabilize the excited state, thereby increasing the efficiency of the photoinitiator. Therefore, the photoinitiator preferably contains one or more halogen groups (e.g., chloro, iodo, and / or bromo groups).

[0045] The composition is preferably in the form of a solution in which all components have good solubility. Therefore, when the composition contains a polar solvent (e.g., water), the photoinitiator preferably contains one or more charged groups, since these charged groups increase the solubility in polar solvents such as water. Suitable charged groups include sulfo and carboxyl groups in the form of free acids or salts, and quaternary ammonium groups.

[0046] Preferably, the photoinitiator does not contain groups with radical scavenging properties (e.g., nitro and thiol groups), as such groups can slow or inhibit curing.

[0047] Preferably, the photoinitiator does not contain more than one hydroxyl group attached to an atom that forms part of a conjugated system. Preferably, the photoinitiator has at least two groups selected from chloro, bromo, iodo, primary, secondary or tertiary amino, alkyl, carbonyl, ether, thioether, carboxyl, sulfo and quaternary ammonium groups, and is free of nitro, thiol and multiple hydroxyl groups.

[0048] In one embodiment, the membrane according to the first aspect of the invention is free of component (b) and its decomposition products. In another embodiment, the membrane according to the first aspect of the invention comprises component (b) and / or its decomposition products.

[0049] For films intended for use in food or pharmaceutical applications, the photoinitiator(s) used as component (b) are preferably known to be non-toxic and / or approved (e.g., by the U.S. Food and Drug Administration (FDA)) for food and / or pharmaceutical use, such as erythrosine B, flavin mononucleotide, curcumin, riboflavin, tartrazine, quinolone yellow, azorubine, amaranth, Ponceau 4R, Allura Red AC, Patent Blue V, indigo carmine, Brilliant Blue FCF, chlorophyll derivatives, copper complexes of chlorophyll or chlorophyllin derivatives, carotenoids, Sunset Yellow FCF, carminic acid, Green S, xanthophyll derivatives, Brilliant Black BN, or one or more thereof. Preferred component (b) is "edible," i.e., suitable for use in foods and beverages, dietary supplements, pharmaceuticals, and cosmetics, and preferably has a visible color, i.e., absorbs light in the wavelength range of 400 to 800 nm.

[0050] The preferred amount of component (b) present in the composition will depend on several factors, including the absorption characteristics and molar extinction coefficient of component (b), its solubility in the rest of the composition, and the degree of overlap between the absorption spectrum of component (b) and the emission spectrum of the radiation source. However, the curable composition preferably comprises 0.002 to 4 wt. %, more preferably 0.005 to 2 wt. %, especially 0.005 to 0.9 wt. %, e.g., 0.02 wt. %, 0.05 wt. %, 0.1 wt. %, 0.3 wt. %, or 0.6 wt. % of component (b).

[0051] Component (b) preferably has a solubility of at least 0.05% by weight, more preferably at least 0.1% by weight, relative to the remainder of the composition. If desired, in addition to component (b), additional initiator(s), such as one or more thermal initiators, may be included in the composition.

[0052] Component (b) typically absorbs light at wavelengths longer than 380 nm to generate excited photoinitiator molecules, which abstract electrons, protons, or both from coinitiator (c) to produce free radicals. The free radicals then cure components (a) and (d) (if present). Thus, the coinitiator can be any chemical capable of generating free radicals in a reaction with component (b) when component (b) is in an electronically excited state, for example, when the composition is irradiated with light that matches the absorption spectrum of component (b) (having an absorption maximum at wavelengths longer than 380 nm).

[0053] Preferably, component (c) comprises a tertiary amine, an acrylated amine, an onium salt (e.g., a salt of an iodonium, sulfonium, phosphonium, or diazonium ion), a triazine derivative, an organohalogen compound, an ether group, a ketone, a thiol, a borate, a sulfide (e.g., a thioether), a pyridinium salt, a ferrocenium salt, or two or more thereof.

[0054] Preferred coinitiators include triethylamine, triethanolamine, methyldiethanolamine, dimethylethanolamine, ethylenediamine-tetra(2-propanol), 1,4-dimethylpiperazine, n-phenyldiethanolamine, 4-(dimethylamino)benzaldehyde, 7-diethylamino-4-methylcoumarin, 2-(diethylamino)ethyl methacrylate, carbon tetrabromide, diphenyliodonium chloride, 2-ethylhexyl 4-dimethylaminobenzoate, 4-(dimethylamino)benzonitrile, 4-methyl-2-methyl-1,3-dimethyl-2,4 ... ethyl dimethylaminobenzoate, dimethylaminopropyl acrylamide, dimethylaminoethyl methacrylate, diphenyliodonium nitrate, N-phenylglycine, 2,4,6-tris(trichloromethyl)-1,3,5-triazine, 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-1,3,5-triazine, hexaethylmelamine, hexamethylenetetramine, piperonyl alcohol, N,N-dimethyl-p-toluidine, L-arginine, and mixtures comprising two or more thereof.

[0055] Although component (c) may contribute to dissolving components of the composition, such as triethanolamine, for purposes of this specification, component (c) is not considered a solvent. The composition preferably contains 0.01 to 40% by weight, more preferably 0.05 to 20% by weight, and even more preferably 0.1 to 5% by weight of component (c).

[0056] The molar ratio of components (b):(c) present in the composition is preferably greater than 1:1, more preferably greater than 1:2, especially greater than 1:5, and more especially greater than 1:10.

[0057] Although generally not preferred, the curable composition can contain nonionic monomers, i.e., monomers that do not contain anionic and cationic groups, typically in small amounts for specific purposes. Examples of component (d) include nonionic monomers such as hydroxyethyl methacrylate and methyl methacrylate, and nonionic crosslinkers such as poly(ethylene glycol) diacrylate, bisphenol-A epoxy acrylate, bisphenol-A ethoxylate diacrylate, tricyclodecane dimethanol diacrylate, neopentyl glycol ethoxylate diacrylate, propanediol ethoxylate diacrylate, butanediol ethoxylate diacrylate, hexanediol diacrylate, hexanediol ethoxylate diacrylate, poly(ethylene glycol-co-propylene glycol) diacrylate, poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) diacrylate, isophorone diacrylamide, divinylbenzene, N,N'-(1,2- dihydroxyethylene)bis-acrylamide, N,N'-methylene-bis-acrylamide, N,N'-ethylenebis(acrylamide), bis(aminopropyl)methylamine diacrylamide, tricyclodecane dimethanol diacrylate, 1,4-diacryloylpiperazine, 1,4-bis(acryloyl)homopiperazine, glycerol ethoxylate triacrylate, trimethylolpropane ethoxylate triacrylate, trimethylolpropane ethoxylate triacrylate, pentaerythritol ethoxylate tetraacrylate, ditrimethylolpropane ethoxylate tetraacrylate, dipentaerythritol ethoxylate hexaacrylate, 1,3,5-triacryloylhexahydro-1,3,5-triazine, 2,4,6-triallyloxy-1,3,5-triazine, and combinations comprising two or more thereof.

[0058] The composition preferably comprises 0 to 50 wt %, more preferably 0 to 30 wt % of component (d). In one embodiment, the composition does not comprise a curable monomer that does not comprise an anionic group or a cationic group.

[0059] Optionally, the composition further comprises one or more solvents as component (e). Component (e) can be any solvent that does not copolymerize with component (a) or (d) (if present) or act as a coinitiator. In one embodiment, component (e) preferably comprises water and optionally an organic solvent, particularly when some or all of the organic solvent is water-miscible. Water is useful for dissolving component (a), and the organic solvent is useful for dissolving other organic components of the composition.

[0060] Component (e) is useful for reducing the viscosity and / or surface tension of the composition, which in some respects makes the membrane manufacturing process easier, especially when the membrane is required to be in the form of a sheet.

[0061] In one embodiment, component (e) comprises at least 50% by weight of water, more preferably at least 70% by weight of water, based on the total weight of component (e). In one embodiment, component (e) comprises less than 30% by weight of an organic solvent, with the remaining solvent being water. In other embodiments, the composition does not comprise an organic solvent, providing environmental benefits due to the complete absence of (volatile) organic solvents. In certain embodiments, water, e.g., water having a pH of less than 7, is used as the solvent.

[0062] In other embodiments, component (e) comprises one or more organic solvents for dissolving the components of the composition, but does not comprise water, which is particularly useful when components (a), (b), (c), and (d), if present, have low solubility in water or are insoluble in water.

[0063] In some embodiments, the composition preferably comprises 0-60 wt. %, more preferably 4-50 wt. %, and most preferably 10-45 wt. % of component (e), while in other embodiments, the composition comprises 35-95 wt. %, preferably 60-90 wt. % of component (e).

[0064] Preferred organic solvents that can be used as or in component (e) include C 1-4 Included are alcohols (e.g., monols such as methanol, ethanol, and propan-2-ol); diols (e.g., ethylene glycol and propylene glycol); triols (e.g., glycerol); carbonates (e.g., ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, di-t-butyl dicarbonate, and glycerin carbonate); dimethylformamide; dimethyl sulfoxide, acetone; N-methyl-2-pyrrolidinone; and mixtures comprising two or more of the above.

[0065] The organic solvent is inert (ie, cannot copolymerize with components (a) or (d), if present). Component (e) can include zero, one, or more than one organic solvent.

[0066] The curable composition may further comprise additives such as surfactants, pH adjusters, viscosity modifiers, structure modifiers, stabilizers, polymerization inhibitors, or two or more of the foregoing. Surfactant or a combination of surfactants can be included in the composition, for example, as a wetting agent or to adjust surface tension.Commercially available surfactants, including radiation curable surfactants, can be utilized.Surfactants suitable for use in the composition include nonionic surfactants, ionic surfactants, amphoteric surfactants, and combinations thereof.

[0067] Preferred surfactants are as described in WO 2007 / 018425, page 20, line 15 to page 22, line 6, which are incorporated herein by reference. Fluorosurfactants are especially preferred, in particular Zonyl® FSN and Capstone® fluorosurfactants (manufactured by EI DuPont). Polysiloxane-based surfactants, in particular Surfynol® from Air Products, are also particularly preferred. TM , Xiameter from DowCorning TM Surfactant, TegoPren from Evonik TM and TegoGlide TM Surfactants, Siltech from Siltech TM and Silsurf TM surfactants, as well as Maxx from Sumitomo Chemical TM Organosilicone surfactants are also preferred.

[0068] The composition preferably contains a polymerization inhibitor (e.g., in an amount less than 2% by weight). This is useful, for example, to prevent premature hardening of the composition during storage. Suitable polymerization inhibitors include hydroquinone, hydroquinone monomethyl ether, 2,6-di-t-butyl-4-methylphenol, 4-t-butyl-catechol, phenothiazine, 4-oxo-2,2,6,6-tetramethyl-1-piperidinyloxy, free radical (4-oxo-TEMPO), 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinyloxy, free radical (4-hydroxy-TEMPO), 2,6-dinitro-sec-butylphenol, tris(N-nitroso-N-phenylhydroxylamine) aluminum salt, and Omnistab. TM IN 510, and mixtures comprising two or more thereof.

[0069] Thus, in a preferred aspect of the invention, the composition comprises: (a) 2 to 95 wt. % of component (a); (b) 0.002 to 4% by weight of component (b), preferably component (b) is a Norrish Type II photoinitiator having an absorption maximum at a wavelength longer than 380 nm, as measured in one or more solvents of water, ethanol, and toluene at a temperature of 23°C; (c) 0.01 to 40 wt. % of component (c); and (d) 0 to 50% by weight of component (d) Includes.

[0070] In one embodiment of this preferred aspect of the invention, the composition further comprises 0 to 60% by weight of component (e), a solvent. Preferably, the membrane is in the form of a sheet, eg, the membrane (eg, a composite ion exchange membrane) comprises a porous support.

[0071] Due to the presence of component (b), the porous support can optionally contain aromatic groups. Thus, the present invention has the advantage of providing a method for making a composite membrane comprising a membrane and an aromatic porous support by a curing process involving light (e.g., ultraviolet or visible light curing) that is much faster than a thermal curing process.

[0072] Examples of porous supports include woven and nonwoven synthetic fabrics and extruded films.Examples include wetlaid and drylaid nonwoven materials, spunbond and meltblown fabrics, and nanofiber webs made from polyethylene, polypropylene, polyacrylonitrile, polyvinyl chloride, polyphenylene sulfide, polyester, polyamide, polyaryletherketones such as polyetheretherketone, and copolymers thereof.Porous supports can also be porous membranes, 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.

[0073] The porous support preferably has an average thickness of 10 to 200 μm, more preferably 20 to 150 μm. Preferably, the porous support has a porosity of 30-95%. The porosity of the support can be measured using a porometer, e.g., Porolux from IB-FT GmbH, Germany. TM It can be determined by 1000.

[0074] The porous support, if present, is one that has been treated, if desired, to modify its surface energy, for example to a value greater than 45 mN / m, preferably greater than 55 mN / m. For example, suitable treatments for improving the wettability and adhesion of membranes to the porous support include corona discharge treatment, plasma glow discharge treatment, flame treatment, ultraviolet radiation treatment, chemical treatment, etc.

[0075] Commercially available porous supports are available from several 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.

[0076] Preferably, the support is a polymeric support. Aromatic porous supports include porous supports derived from one or more aromatic monomers, such as aromatic polyamide (aramid), (sulfonated) polyphenylene sulfone, poly(phenylene sulfide sulfone), aromatic polyester (e.g., polyethylene terephthalate (PET) or polybutylene terephthalate (PBT)), aromatic polyether ether ketone, polyphenylene sulfide, or a combination of two or more thereof. In one embodiment, the support strongly absorbs UV light (380 nm or less). The support is considered to be strongly absorbing when it has a transmittance of less than 90% at wavelengths longer than 340 nm as measured by a UV spectrometer.

[0077] Examples of commercially available aromatic porous supports include Teijin, Hirose, Mitsubishi Paper Mills Ltd and Sefar AG. The thickness of the membrane according to the first aspect of the invention, including the multilayer support (if present), is preferably less than 250 μm, more preferably between 5 and 200 μm, most preferably between 10 and 150 μm, for example about 20, about 50, about 75 or about 100 μm.

[0078] The membrane preferably has an ion exchange capacity of at least 0.1 meq / g, more preferably at least 0.3 meq / g, particularly greater than 0.6 meq / g, and even more particularly greater than 1.0 meq / g, based on the total dry weight of the membrane (including the porous support, if present). Ion exchange capacity can be measured by titration, as described by Dlugolecki et al. in J. of Membrane Science, 319 (2008), p. 217.

[0079] The membrane preferably exhibits a swelling in water of less than 100%, more preferably less than 75%, and most preferably less than 60%. The degree of swelling can be controlled by the amount of crosslinker, the amount of non-curable compounds, and by selecting appropriate parameters in the curing step, as well as the properties of the porous support (if present). The electrical resistivity, permselectivity, and degree of swelling in water (also known as water uptake) can be measured by the method described by Dlugolecki et al. in J. of Membrane Science, 319 (2008), pp. 217-218.

[0080] Typically, the membrane is substantially non-porous, e.g., in a swollen state that does not allow impregnation with small molecules. Preferably, all pores in the membrane are smaller than the detection limit of a standard scanning electron microscope (SEM). Thus, using a Jeol JSM-6335F field emission SEM (2 kV accelerating voltage, 4 mm working distance, 4 aperture, 1.5 nm thick Pt coated sample, 100,000x magnification, 3° oblique field of view), the average pore size is generally smaller than 2 nm, preferably smaller than 1 nm.

[0081] The membrane preferably has low water permeability so that (hydrated) ions can pass through the membrane but (free) water molecules do not easily pass through the membrane. The membrane preferably has a water permeability of 1×10 -9 m 3 / m 2 less than .s.kPa, more preferably 1×10 -10m 3 / m 2 less than .s.kPa, most preferably 5 x 10 -11 m 3 / m 2 Less than .s.kPa, especially 3×10 -11 m 3 / m 2 It is less than .s.kPa.

[0082] The membrane is sensitive to small cations (e.g., Na + ) or anions (e.g., Cl - ) preferably has a selective permeability of more than 90%, more preferably more than 95%. The membrane preferably has a resistance of 15 ohm.cm 2 less than, more preferably 10 ohm.cm 2 Less than, most preferably 8 ohm.cm 2 In certain applications, for example, for processes operating with low conductivity streams, such as systems used to produce ultrapure and / or drinking water, a high electrical resistance may be acceptable, especially when the permselectivity is very high, e.g., greater than 95%, and the water permeation is very low.

[0083] According to a second aspect of the present invention there is provided a process for preparing an ion exchange membrane which comprises curing a composition as defined in the first aspect of the present invention. The process of the present invention can contain further steps, if desired, such as applying the composition to a porous support before curing and washing and / or drying the cured composition (i.e., membrane).

[0084] Optionally, the process includes the further step of washing unreacted composition from the ion exchange membrane. While in one embodiment, membranes according to the present invention can be prepared batchwise using a stationary support, it is much more preferred to prepare them continuously using a moving support, particularly a moving porous support. The porous support can be in the form of a continuously unwound roll, or in the form of a hollow fiber, or the porous support can be mounted on a carrier, such as a continuously driven belt (or a combination of these methods). Using such techniques, the composition can be applied to the porous support continuously, or it can be applied to the porous support in a large-scale batchwise manner.

[0085] The curable composition can be applied to the porous substrate by any suitable method, such as curtain coating, blade coating, air knife coating, knife-over-roll coating, slide coating, nip roll coating, forward roll coating, reverse roll coating, microroll coating, dip coating, foulard coating, kiss coating, rod bar coating, or spray coating. The curable composition typically forms a continuous film layer on the porous substrate, or the carrier or porous substrate may be impregnated with the composition. Multiple layers can be coated simultaneously or sequentially. When multiple layers are coated, the curable compositions can be the same or different.

[0086] Thus, the process step of applying the composition to the porous substrate can be performed more than once, with or without curing between each application of the composition. When the composition is applied to both sides of the porous substrate, the resulting impregnated substrate can be symmetrical or asymmetrical. Thus, the composition applied to one side of the porous substrate can be the same or different from the composition applied to the other side of the porous substrate.

[0087] Thus, in a preferred process, the composition is continuously applied to a moving support (preferably a porous support) preferably by a manufacturing unit comprising one or more composition application stations, one or more irradiation sources for curing the composition, a membrane collection station, and means for moving the porous support from the composition application station(s) to the irradiation source(s) and back to the membrane collection station.

[0088] The composition application station(s) can be located upstream relative to the irradiation source(s), which in turn is located upstream relative to the membrane collection station. To produce a curable composition that is sufficiently fluid for application by high-speed coating machines, it is preferred that the composition have a viscosity of less than 5000 mPa·s measured at 23° C., more preferably from 1 to 1500 mPa·s measured at 23° C. Most preferably, the viscosity of the composition is from 2 to 500 mPa·s measured at 23° C.

[0089] Using suitable coating techniques, the composition can be applied to a moving porous substrate at speeds of more than 1 m / min, for example more than 5 m / min, preferably more than 10 m / min, more preferably more than 15 m / min, for example more than 20 m / min, or even faster speeds such as 30 m / min or even up to 40 m / min.

[0090] During curing, components (a) and (d), if present, typically polymerize to form a film. Curing preferably occurs quickly enough that a film forms within 30 seconds. If desired, further curing may be applied to achieve a finish, although this is generally not necessary.

[0091] Curing of the composition preferably begins within 3 minutes, more preferably within 60 seconds, after application of the composition to the substrate. Curing is preferably achieved by irradiating the composition for less than 30 seconds, more preferably less than 10 seconds, particularly less than 3 seconds, and even more particularly less than 2 seconds. In a continuous process, irradiation is continuous, and the speed at which the composition moves through the irradiation beam is the primary factor determining the curing time. The exposure time is determined by the irradiation time with the focused beam; stray "light" is generally too weak to have a significant effect. White, blue, or green light is preferably used for curing. Suitable wavelengths are longer than 380 nm, provided that the wavelength of the light matches the absorption wavelength of component (b).

[0092] Suitable light sources having a wavelength in the range of 380-800 nm include light-emitting diodes (e.g., white (450 nm, and a broad peak at 550 nm extending to 750 nm), blue (450 nm), green (530 nm), yellow (590 nm), red (625 nm), or UV-V (385, 395, 405, or 420 nm); gas discharge lamps (mercury (430 and 550 nm), gallium (400 and 410 nm), indium (410 and 450 nm), thallium (530 nm), or hydrogen (490 nm)); sulfur plasma lamps (broad peak of the complete visible spectrum with a maximum at 500 nm). Suitable light-emitting diodes can be obtained from Cree, Osram, Hoenle, and Chromasens. Gas discharge lamps can be obtained from Heraus, Hoenle, and uv-technik meyer GmbH. Sulfur plasma lamps are available from Plasma-international and PlasmaBright. Preferably, light from a light emitting diode ("LED") is used for curing.

[0093] The energy output of the radiation source used to cure the composition is preferably 1 to 1000 W / cm, preferably 2 to 500 W / cm, but may be higher or lower as long as cure is achieved. The exposure intensity is one of the parameters that can be used to control the degree of cure and thereby influence the final structure of the film. The exposure dose is preferably at least 40 mJ / cm, as measured with a Power Puck II radiometer from Uvitron. 2 , more preferably 40 to 1500 mJ / cm 2 , and most preferably 70 to 900 mJ / cm 2 A typical example of a curing light source is a 420 nm monochromatic LED with an output of 25 W / cm supplied by Hoenle. Alternatives are 385 nm and 405 nm LEDs from the same supplier.

[0094] To reach a desired exposure dose at high coating speeds, more than one radiation source may be used so that the composition is irradiated more than once. According to a third aspect of the present invention there is provided the use of an ion exchange membrane according to the first aspect of the present invention for the treatment of an aqueous stream, for example for water softening, tartaric acid stabilisation of wine, desalting of whey, purifying liquids (e.g. water, sugar syrup, fruit juice, organic solvents, mineral oil and metal ion solutions), catalysis in chemical reactions, dehumidification or for the production of energy.

[0095] Although the membranes according to the invention are primarily intended for use in water purification (e.g., by electrodeionization or electrodialysis, including continuous electrodeionization (CEDI) and electrodialysis reversal (EDR)), they can also be used for other purposes, such as capacitive deionization, e.g., as used in flow-through capacitors (FTCs), Donnan or diffusion dialysis (DD) for e.g., fluoride removal or acid recovery, dehumidification, pervaporation for dehydration of organic solvents, fuel cells, redox flow batteries (RFBs), electrolysis of water (EL) or electrolysis for chlor-alkali production (EL), and electrodialysis reversal (RED).

[0096] Films according to the invention can also be used for other purposes, such as protective coatings (e.g., in printing, stereolithography and 3D printing), as light-curable adhesives, in dental resins, or for filtration purposes.

[0097] According to a fourth aspect of the present invention, there is provided an electrodialysis or electrodialysis reversal unit, electrodeionization module, flow-through capacitor, diffusion dialysis device, membrane distillation module, electrolyzer, redox flow battery, or acid-base flow battery, comprising one or more membranes according to the first aspect of the present invention. The electrodeionization module is preferably a continuous electrodeionization module.

[0098] Preferably, the electrodialysis or electrodialysis reversal unit or electrodeionization module or flow-through capacitor comprises at least one anode, at least one cathode and two or more membranes according to the first aspect of the invention.

[0099] In preferred embodiments, the unit comprises at least 1, more preferably at least 5, for example 36, 64, 200, 600, or up to 1500, membrane pairs according to the first aspect of the invention, the number of membranes depending on the application. The membranes may, for example, be used in a plate-and-frame or stacked-disk configuration, or in a spiral-wound design.

[0100] The present invention offers several advantages: (i) The use of component (b) with specific absorption characteristics allows components (a) and (d) to contain aromatic groups that absorb light in the wavelength range of 200 to 380 nm. Thus, not only aromatic monomers or oligomers can be used to prepare the ion exchange membranes of the present invention; porous supports made from aromatic polymers can also be used. (ii) If component (b) is safe to eat, the film may be suitable for food and / or pharmaceutical use. (iii) If component (b) has a color visible to humans, the resulting membrane is colored: it absorbs light in the wavelength range of 400 to 800 nm. By using a different component (b) for each membrane type (e.g., various membrane types such as anion exchange membranes, cation exchange membranes, monovalent anion exchange membranes, and monovalent cation exchange membranes), or by using different amounts of the same component (b), it is possible to provide each membrane type with a unique color or depth of color, which makes assembly of membrane stacks easier and reduces the likelihood of creating stacks in which the ion exchange membranes are in the wrong order. (iv) The composition can be cured using visible light, for example, LED light. Curing with visible light can have many advantages compared to UV light (lower energy consumption, no harmful UV radiation, no or much less wasted IR radiation, thus less heating of the product, no ozone formation in the irradiation zone, longer life of the irradiation source, and higher spectral matching, which can reach 100% when monochromatic light is used).Therefore, LED light can be much more efficient than using UV light. (v) To maximize the spectral match between the emission spectrum of the light source and the absorption spectrum of the photoinitiator, an ideal illumination source from a number of possible sources can be selected for each photoinitiator system. (vi) The curable composition can be handled under yellow or red light conditions, depending on the photoinitiator chosen. (vii) Curing of the composition to form a film is less inhibited by the presence of oxygen than prior art processes that use Type I photoinitiators and UV light to cure. (viii) The photoinitiator system is more efficient, allowing the use of lower amounts of photoinitiator than prior art processes.

[0101] The present invention also provides the use of membranes according to the first aspect of the invention to prepare a membrane stack. A typical stack comprises alternating anionic and cationic membranes, each of which has the same color or color depth as the other and a different color and / or color depth from the cationic membranes. The anionic and cationic membranes are preferably as defined in the first aspect of the invention. Accordingly, the present invention provides a stack of ion exchange membranes comprising alternating anionic and cationic membranes, each of which has the same color or color depth as the other and a different color and / or color depth from the cationic membranes. Furthermore, when monovalent selective membranes are used, they can be given a different color from standard membranes by selecting a different component (b) or a different amount of component (b). Thus, the stack preferably comprises AEMs and CEMs obtained from the composition described above in connection with the first aspect of the invention, containing a sufficient amount of component (b) to produce a visible difference between the AEMs and CEMs of the stack. The stack preferably comprises AEMs and CEMs obtained from a composition as described above in relation to the first aspect of the invention comprising at least 0.0005 wt%, more preferably at least 0.001 wt%, especially at least 0.01 wt% of component (b). The stack preferably comprises AEMs and CEMs obtained from a composition as described above in relation to the first aspect of the invention comprising less than 4 wt%, more preferably less than 0.5 wt%, especially less than 0.2 wt% of component (b).

[0102] Since component (b) can remain in the membrane after curing, the present invention further provides an ion exchange membrane comprising at least 0.0005 wt. %, more preferably at least 0.001 wt. %, and especially at least 0.01 wt. % of component (b). Such an ion exchange membrane preferably contains less than 4 wt. %, more preferably less than 0.5 wt. %, and especially less than 0.2 wt. % of component (b). Component (b) is as defined above in relation to the first aspect of the present invention.

[0103] It is often not possible to add dyes or pigments to prior art compositions that apply type I photoinitiators, since these compounds interfere with the curing process due to their high absorption in the UV region. [Example]

[0104] The invention will now be illustrated by way of non-limiting examples in which all parts and percentages are by weight unless otherwise stated. In the examples, the following properties were measured by the methods described below. material Na-AMPS is the sodium salt of 2-acryloylamido-2-methylpropanesulfonic acid from Sigma-Aldrich. DMAPAA-Q Kohjin's 3-acrylamidopropyl-trimethylammonium chloride. LiP is lithium p-styrenesulfonate, a monomer from Tosoh Corp. VBTMAC is 4-vinylbenzyltrimethylammonium chloride from Sigma-Aldrich TEOA is triethanolamine, a coinitiator from Sigma-Aldrich. and diphenyliodonium chloride, a coinitiator from IO TCI Co. Darocur TM 1173 is a Type I photoinitiator from BASF. 2223-10 Viledon® Novatexx 2223-10 (a non-woven polypropylene / polyethylene porous support from Freudenberg Filtration Technologies, containing no aromatic groups). CL-3 is N,N-(1,4-phenylenebis(methylene))bis(3-acrylamido-N,N-dimethylpropan-1-aminium) bromide, a cationically charged crosslinker as described in International Publication No. WO2013011273.

[0105] Riboflavin, resazurin, rhodamine B, quinoline yellow WS, neutral red, and curcumin are Type II photoinitiators from TCI Co., which have adsorption maxima at wavelengths longer than 380 nm, measured at a temperature of 23°C in one or more of the following solvents: water, ethanol, and toluene.

[0106] Erythrosin B, eosin Y disodium salt, flavin mononucleotide, lumichrome, zinc phthalocyanine, rose bengal, methylene blue, acridine, safranine-O, 1-amino-anthraquinone, carminic acid, thiomichler's ketone, martius yellow, ethyl violet, camphorquinone, quinaldine red, and fluorescein sodium salt are type II photoinitiators from Sigma-Aldrich, which have adsorption maxima at wavelengths longer than 380 nm, measured at a temperature of 23° C. in one or more of the following solvents: water, ethanol, and toluene.

[0107] 1,4-Anthraquinone, benzophenone, Michler's ketone, anthraquinone-2-sulfonate, and isopropylthioxanthone (ITX) are optically active reference molecules from Sigma-Aldrich, which have adsorption maxima at wavelengths longer than 380 nm, measured at a temperature of 23 °C in one or more of the following solvents: water, ethanol, and toluene.

[0108] A summary of the properties of some photoinitiators is given in Table 1.

[0109] [Table 1]

[0110] In Table 1, Abs.max. (nm) means the absorption maximum in nm when measured in the solvent specified in column 3 at a temperature of 23°C. The absorption maxima shown in Table 1 were measured using a Varian Cary 100 focused double-beam UV / Vis spectrophotometer. Measurements were performed at 23 °C using a quartz cuvette with a 1 mm path length at a concentration of 0.01 wt% photoinitiator in solvent (pure water, ethanol, or toluene). Absorption spectra were measured from 800 to 200 nm.

[0111] The cure speed of compositions including photoinitiators was tested on a Mettler Toledo DSC822e Differential Scanning Calorimeter (DSC) equipped with a Sylvania ES50 V4 620LM DIM 865 36° SL lamp.

[0112] Preparation of Membrane Examples 1 to 34 and Comparative Membrane Examples CEX1 to CEX4 The compositions set forth in Table 2 below were prepared by dissolving the specified components in purified water (water supplemented to bring the amount to 100% by weight). In the last column of Table 2, "A" means anion exchange membrane (CEM) and "C" means cation exchange membrane (AEM). In Table 2, "Time (sec)" means the time in seconds required for the composition to cure 90%. The point at which the composition was 90% cured was determined by the DSC method described above.

[0113] Procedure: 20 mg of each test composition was placed in a DSC pan at 25°C and irradiated for 10 minutes at a distance of 1 cm using a Sylvania ES50 V4 620LM DIM 865 36° SL lamp. Following cure, the resulting heat of reaction was measured against a reference DSC pan containing 20 mg of the same photoinitiator used in the test composition in the same solvent. Test compositions were considered acceptable if their cure time in seconds (i.e., the time in seconds required for the composition to cure 90%) was less than 300 seconds. Preferably, the cure time was less than 150 seconds. The results are shown in Table 2.

[0114] [Table 2]

[0115] [Table 3]

[0116] [Table 4]

[0117] For some examples from Table 2, the extinction coefficients of the compositions were determined with and without a photoinitiator. A ratio (A1 / A2) > 1.5 is preferred. The results are shown in Table 3 below. A1 is the extinction coefficient of the composition at wavelength X nm; A2 is the extinction coefficient at wavelength X nm of a composition identical to the composition except that component (b) is omitted; and X nm is the wavelength of the absorption maximum of component (b).

[0118] [Table 5]

[0119] Anion exchange membranes (AEMs) were prepared using the compositions listed in Table 4.

[0120] [Table 6]

[0121] The compositions described in Table 4 were applied to a PET sheet using a 100 μm Meyer bar. A porous support (2223-10) was placed on the layer of composition, and excess composition was scraped off. The composition present in the porous support was then cured by placing it on a conveyor belt set at 5 m / min using a Heraeus F450 microwave-driven UV curing system equipped with a medium-pressure mercury bulb (240 W / cm, 100%) to obtain an AEM.

[0122] The presence of photoinitiator in the film can be determined visually, spectrophotometrically, or analytically. The amount of photoinitiator was analytically determined by extraction (twice). Analysis was performed by cutting a 10 x 10 cm piece of AEM into small rectangles, placing them in a 20 mL glass container, and adding 5 mL of purified water. The container was capped and wrapped in aluminum foil to protect it from light. The container was shaken on a rotary shaker at 125 RPM for 24 hours. The contents of the container were then filtered through a 0.45 μm cellulose filter and transferred to an HPLC vial.

[0123] Analysis method HPLC Instrument: Waters ACQUITY arc HPLC Detector: 2998 ACQ-PDA Column: TKSgelODA-100V HPLC column (4.6 x 150, 5 μm) Maximum pressure: 450[bar] Column temperature: 40°C Sample temperature: 5°C Absorbance, separation: 254, 270, 280, 440, 540, 485(4.8)[nm] 254nm = Identification of riboflavin monophosphate 485nm = Identification of Erythrosin B Injection volume: 100 microliters Run time: 24 minutes Next injection delay: 0 minutes Attached sample loop: 250 microliters Solvent: A: Acetonitrile + 0.1% trifluoroacetic acid B: Pure water + 0.1% trifluoroacetic acid

[0124] [Table 7]

[0125] [Table 8] The present invention includes the following aspects. [1] (a) a curable monomer containing at least one anionic or cationic group; (b) a photoinitiator having an absorption maximum at a wavelength longer than 380 nm, measured at a temperature of 23° C. in one or more of water, ethanol, and toluene; (c) at least one coinitiator; and Optionally (d) a curable monomer free of anionic and cationic groups; 1. An ion exchange membrane obtainable by curing a composition comprising: [2] 2. The ion exchange membrane according to 1, wherein component (b) is a photoinitiator having an absorption maximum in a wavelength range of 385 to 800 nm when measured at a temperature of 23°C in one or more solvents selected from water, ethanol, and toluene. [3] 3. The ion exchange membrane according to 1 or 2, wherein the photoinitiator is a Norrish type II photoinitiator. [4] 4. The ion exchange membrane according to any one of 1 to 3, wherein the composition further comprises (e) a solvent. [5] The molar extinction coefficient of component (b) at the absorption maximum is at least 7500 M -1 cm -1 5. The ion exchange membrane according to any one of 1 to 4, wherein [6] 6. The ion exchange membrane according to any one of 1 to 5, wherein the coinitiator is a chemical substance capable of generating free radicals in a reaction with component (b) when component (b) is in an electronically excited state. [7] 7. The ion exchange membrane according to any one of claims 1 to 6, wherein the composition satisfies formula 1: (A1 / A2)>1.5 formula 1 [In formula: A1 is the extinction coefficient of the composition at wavelength X nm; A2 is the extinction coefficient at wavelength X nm of a composition identical to the composition except that component (b) is omitted; and X nm is the wavelength of the absorption maximum of component (b); All damping coefficients are measured at a temperature of 23°C]. [8] 8. The ion exchange membrane according to any one of 1 to 7, wherein component (c) comprises a tertiary amine, an acrylated amine, an onium salt (e.g., a salt of an iodonium, sulfonium, phosphonium, or diazonium ion), a triazine derivative, an organic halogen compound, an ether group, a ketone, a thiol, a borate, a sulfide, a pyridinium salt, a ferrocenium salt, or two or more thereof. [9] 9. The ion exchange membrane according to any one of claims 1 to 8, wherein component (b) comprises a photoinitiator derived from xanthene, flavin, curcumin, porphyrin, anthraquinone, phenoxazine, camphorquinone, phenazine, acridine, phenothiazine, xanthone, thioxanthone, thioxanthene, acridine, acridone, flavone, coumarin, fluorenone, quinolone, naphthaquinone, quinolinone, arylmethane, azo, benzophenone, carotenoid, cyanine, phthalocyanine, dipyrrin, squarine, stilbene, styryl, triazine and / or anthocyanin, and in each case has an absorption maximum at a wavelength longer than 380 nm when measured at a temperature of 23°C in a solvent selected from water, ethanol and toluene.

[10] The composition comprises: (a) 2 to 95 wt. % of component (a); (b) 0.002 to 4 wt. % of component (b); (c) 0.01 to 40 wt. % of component (c); and (d) 0 to 50% by weight of component (d) 10. The ion exchange membrane according to any one of 1 to 9, comprising:

[11] 11. The ion exchange membrane according to any one of 1 to 10, wherein the composition further comprises 0 to 60 wt % of (e) a solvent.

[12] 12. The ion exchange membrane according to 4 or 11, wherein component (e) comprises at least 50% by weight of water.

[13] 13. The ion exchange membrane according to any one of 1 to 12, further comprising a porous support.

[14] An ion exchange membrane comprising at least 0.0005% by weight of a photoinitiator, the photoinitiator having an adsorption maximum at a wavelength longer than 380 nm when measured in one or more solvents selected from water, ethanol, and toluene at a temperature of 23°C.

[15] 13. A process for preparing an ion exchange membrane, comprising curing a composition as defined in any one of claims 1 to 12.

[16] The composition is applied at a dose of at least 40 mJ / cm 2 and curing with light having a peak irradiance at a wavelength longer than 380 nm.

[17] 17. The process of claim 15 or 16, comprising applying the composition to a porous support before curing.

[18] 18. The process of any one of claims 15 to 17, further comprising washing and / or drying the cured composition.

[19] 15. Use of an ion exchange membrane according to any one of claims 1 to 14 for the treatment of water streams, such as water softening, tartaric acid stabilisation of wine, desalination of whey, purification of liquids (e.g. water, sugar syrup, fruit juice, organic solvents, mineral oil and metal ion solutions), catalysis in chemical reactions, dehumidification, or production of energy.

[20] 15. A stack of ion exchange membranes comprising alternating anionic membranes according to any one of claims 1 to 14 and cationic membranes according to any one of claims 1 to 14, wherein the anionic membranes each have the same color and / or depth of color as each other and a different color and / or depth of color from the cationic membranes.

[21] 15. An electrodialysis or electrodialysis reversal unit, electrodeionization module, flow-through capacitor, diffusion dialysis apparatus, membrane distillation module, electrolyzer, redox flow battery or acid-base flow battery comprising one or more membranes according to any one of claims 1 to 14.

Claims

1. (a) a curable monomer containing at least one anionic or cationic group; (b) has an absorption maximum at a wavelength longer than 380 nm and an absorption peak of at least 7500 nm when measured in one or more solvents selected from water, ethanol, and toluene at a temperature of 23°C; －１ cm －１ a Norrish Type II photoinitiator having a molar extinction coefficient of (c) at least one coinitiator, wherein the coinitiator is a chemical capable of generating free radicals in a reaction with component (b) when component (b) is in an electronically excited state; and Optionally, (d) a curable monomer that is free of anionic and cationic groups; An ion exchange membrane obtainable by curing a composition comprising: at least one of the curable monomers present in the composition comprises an aromatic group; The ion exchange membrane, wherein the component (c) comprises a tertiary amine, an acrylated amine, an onium salt, a triazine derivative, an organic halogen compound, an ether, a ketone, a thiol, a borate, a sulfide, a pyridinium salt, a ferrocenium salt, or two or more thereof.

2. The ion exchange membrane of claim 1, wherein the composition satisfies formula 1: (A1 / A2)>1.5 Formula 1 [In the formula: A1 is the extinction coefficient of the composition at wavelength X nm; A2 is the extinction coefficient at wavelength X nm of a composition identical to the composition except that component (b) is omitted; and X nm is the wavelength of the absorption maximum of component (b); All extinction coefficients are measured at a temperature of 23°C].

3. 3. The ion exchange membrane according to claim 1, wherein component (b) comprises a photoinitiator derived from xanthene, flavin, curcumin, porphyrin, anthraquinone, phenoxazine, phenazine, acridine, phenothiazine, xanthone, thioxanthone, thioxanthene, acridine, acridone, flavone, coumarin, fluorenone, quinolone, naphthaquinone, quinolinone, arylmethane, azo, benzophenone, carotenoid, cyanine, phthalocyanine, dipyrrin, squarine, stilbene, styryl, triazine and / or anthocyanin, and in each case has an absorption maximum at a wavelength longer than 380 nm when measured at a temperature of 23° C. in a solvent selected from water, ethanol and toluene.

4. The composition comprises: (a) 2 to 95 wt. % of component (a); (b) 0.002 to 4 wt. % of component (b); (c) 0.01 to 40 wt. % of component (c); (d) 0 to 50 wt. % of component (d); and (e) 0 to 60% by weight of a solvent as component (e) The ion exchange membrane according to any one of claims 1 to 3, comprising:

5. The ion exchange membrane according to any one of claims 1 to 4, further comprising a porous support.

6. 6. The ion exchange membrane according to claim 1, comprising at least 0.0005% by weight of a photoinitiator, wherein the photoinitiator has an adsorption maximum at a wavelength longer than 380 nm and an adsorption maximum of at least 7500 M when measured in one or more solvents selected from the group consisting of water, ethanol, and toluene at a temperature of 23°C. －１ cm －１ The ion exchange membrane has a molar extinction coefficient of

7. At least 40 mJ / cm ２ 7. A process for preparing an ion exchange membrane, comprising curing a composition as defined in any one of claims 1 to 6 with light having a peak irradiance at a wavelength longer than 380 nm using a dose of

8. Use of an ion exchange membrane according to any one of claims 1 to 6 for the treatment of water streams, water softening, tartaric acid stabilisation of wine, desalination of whey, purification of liquids, catalysis in chemical reactions, dehumidification or production of energy.

9. 10. A stack of ion exchange membranes comprising alternating anionic membranes obtained by curing a composition comprising a curable monomer comprising at least one anionic group according to any one of claims 1 to 6 and cationic membranes obtained by curing a composition comprising a curable monomer comprising at least one cationic group according to any one of claims 1 to 6, wherein the anionic membranes each have the same color and / or color depth as the other membrane and a different color and / or color depth from the cationic membrane.

10. 7. An electrodialysis or electrodialysis reversal unit, an electrodeionization module, a flow-through capacitor, a diffusion dialyzer, a membrane distillation module, an electrolyzer, a redox flow battery or an acid-base flow battery comprising one or more membranes according to any one of claims 1 to 6.

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