Film and method for removing trace metals

Abstract

This invention provides an improved method for removing metal contaminants from organic solvents. [Solution] This disclosure provides a specific porous polymer film coated with a crosslinked polymerization monomer, which contains a monomer that has an electric charge when immersed in an organic liquid. The film of this disclosure is useful for removing trace amounts of metal impurities, thereby providing an ultra-high purity organic liquid.

Description

[Technical Field]

[0001]

[0001] This disclosure relates to a film useful for removing trace metals from a solvent, particularly a liquid such as a photoresist chemical. [Background technology]

[0002]

[0002] Filter products are essential tools in modern industry, used to remove unwanted substances from the flow of useful fluids. Useful fluids processed using filters include water, liquid industrial solvents and processing fluids, industrial gases used in manufacturing or processing (such as semiconductor manufacturing), and liquids for medical or pharmaceutical applications. Unwanted substances removed from liquids include impurities and contaminants such as particles, microorganisms, and dissolved chemical species. Specific examples of filter applications include use in liquid materials for the manufacture of semiconductors and microelectronic devices.

[0003]

[0003] In order to perform the filtration function, the filter includes a filter membrane that serves to remove unwanted substances from the fluid passing through the filter membrane. The filter membrane may be in the form of a flat sheet as needed, and it may be rolled (e.g., helically), flat, pleated, or disc-shaped. Alternatively, the filter membrane may be in the form of hollow fibers. The filter membrane may be housed in a housing or otherwise supported so that the fluid to be filtered enters through the filter inlet and must pass through the filter membrane before passing through the filter outlet.

[0004]

[0004] Filter membranes can be constructed with a porous structure having an average pore size that can be selected based on the application of the filter, i.e., the type of filtration performed by the filter. Typical pore sizes are in the range of microns or submicrons, for example, about 0.001 microns to about 10 microns. Membranes with an average pore size of about 0.001 to about 0.05 microns are sometimes classified as ultrafiltration membranes. Membranes with a pore size of about 0.05 to 10 microns are sometimes called microporous membranes.

[0005]

[0005] Filter membranes having pore sizes in the micron or submicron range are effective in removing unwanted substances from a fluid flow by a sieving mechanism, a non-sieving mechanism, or both. A sieving mechanism is a mode of filtration in which particles are removed from a liquid flow by mechanically holding them on the surface of the filter membrane. This works by mechanically hindering the movement of particles and holding them within the filter, mechanically preventing the flow of particles through the filter. Typically, particles may be larger than the pores of the filter. A "non-sieving" filtration mechanism is a mode of filtration in which the filter membrane filters suspended particles or dissolved substances contained in a fluid flow by means other than mechanical means, such as an electrostatic mechanism in which particulate or dissolved impurities are attracted to and held on the filter surface by electrostatics and removed from the fluid flow. The particles may be dissolved or solids with a particle size smaller than the pores of the filter medium.

[0006]

[0006] Removing ionic substances such as dissolved anions or cations from solutions is important in many industries, such as the microelectronics industry, where even very low concentrations of ionic contaminants or particles can adversely affect the quality and performance of microprocessors and memory devices.

[0007]

[0007] There is still a need for improved methodologies for removing metal contaminants from organic solvents. In particular, there is still a need for materials that enable the removal of metal contaminants used in semiconductor processing industries, such as in photoresist applications, where extremely low levels of ionic metal contaminants are required, i.e., solvents at the part per trillion level (PPT). [Overview of the project]

[0008]

[0008] In summary, the present disclosure provides a variety of porous membranes, membrane assemblies, and filter devices capable of removing trace amounts of metal ions from organic liquids. In some embodiments, the organic liquid may be a solvent used in the manufacture of semiconductor and microelectronic devices, and this includes, but is not limited to, solvents used in photolithography applications. In certain embodiments, the membranes of the present disclosure are composed of poly(tetrafluoroethylene), and the membranes are at least partially coated with a polymer prepared from the polymerization of at least one monomer and at least one crosslinking agent, the at least one monomer being selected from a variety of charged monomers. The membrane assemblies of the present disclosure exhibit improved metal ion removal efficiency, and the devices of the present disclosure demonstrate superior performance, as the amount of various metal ions leaching from the porous polymer membrane contained therein when placed in a solvent in idle mode is found to be remarkably small, less than 0.080 ppb. This result can be compared to data showing metal ion leaching from similar membranes having a UPE polymer backbone, as shown in the following examples. The coatings described herein are prepared from one or more crosslinking agents and one or more monomers, comprising, or essentially comprising, the monomers and crosslinking agents described herein. [Brief explanation of the drawing]

[0009] [Figure 1]

[0009] This figure shows an exemplary filter device. [Modes for carrying out the invention]

[0010]

[0010] Where used in this specification and the appended claims, the singular forms “a,” “an,” and “the” refer to multiple subjects unless the context clearly indicates otherwise. Where used in this specification and the appended claims, the term “or” is used generally to mean “and / or” unless the context clearly indicates otherwise.

[0011]

[0011] The term “approximately” usually refers to a range of numbers that are considered equivalent to the stated value (for example, having the same function or result). Often, the term “approximately” may include numbers rounded to the nearest significant figure.

[0012]

[0012] A numerical range expressed using an endpoint includes all numbers within that range (for example, 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).

[0013]

[0013] In a first embodiment, the present disclosure relates to a film assembly, a. A porous membrane comprising poly(tetrafluoroethylene), having a coating on the film, wherein the coating is prepared from the polymerization of at least one monomer and at least one crosslinking agent, and the monomer has a positive charge in an organic liquid. b. A porous membrane comprising poly(tetrafluoroethylene), wherein the film has a coating thereon, the coating being prepared from the polymerization of at least one monomer and at least one crosslinking agent, the monomer having a negative charge in an organic liquid. Includes, The assembly provides a membrane assembly that exhibits a total removal efficiency of over 90% of one or more metal ions selected from lithium, boron, sodium, magnesium, aluminum, potassium, calcium, titanium, vanadium, chromium, manganese, iron, nickel, copper, zinc, molybdenum, silver, tin, barium, and lead ions from a feed stream containing 1 ppb of metal ions selected from lithium, boron, sodium, magnesium, aluminum, potassium, calcium, titanium, vanadium, chromium, manganese, iron, nickel, copper, zinc, molybdenum, silver, tin, barium, and lead ions.

[0014]

[0014] The membrane assemblies referred to herein are generally pleated packs of two or more membranes stacked on top of each other, through which an organic liquid passes during operation. Supporting materials such as polymer screens may also be placed between the membranes as needed.

[0015] As described above, it has been found that the porous polytetrafluoroethylene (PTFE) membrane modified in this specification provides a purified solvent. The underlying PTFE membrane is commercially available and widely available in the market. The PTFE membranes described in this specification can have various geometric configurations such as flat sheets, corrugated sheets, pleated sheets, hollow fibers, etc. The porous membrane can have a pore structure that is isotropic or anisotropic, with or without a skin, symmetric or asymmetric, any combination of these, or can be a composite membrane including one or more retention layers and one or more support layers. Further, the coated porous membrane may or may not be supported by a web, net, cage, etc.

[0016]

[0016] To prepare the membranes of the present disclosure, the methodology of U.S. Patent Publication No. 2020 / 0206691, which is hereby incorporated by reference in its entirety, can be utilized.

[0017]

[0017] That is, by coating the membrane with a coating having the desired pendant functional groups, specific functional groups having a positive or negative charge can be introduced onto the surface of the polymer membrane.

[0018]

[0018] Generally, the coating is composed of an organic backbone formed from specific polymerization monomers. Thus, the coating can be prepared from various monomers having at least one carbon-carbon double bond, including monomers and crosslinking agents, and is prepared by initiating a free radical polymerization reaction, after which the coating is provided on the surface of the PTFE membrane. The crosslinking agent is generally a bifunctional monomer. The polymerization and crosslinking of the polymerizable monomer onto the porous membrane substrate are carried out such that at least a part of the porous membrane, including the internal pore surface of the porous membrane, is modified with a crosslinked polymer coating over the entire surface. Thus, it should be understood that the present disclosure encompasses coating a desired portion (greater than 0% to 100%) of the surface of the porous membrane with a crosslinked polymer composition.

[0019]

[0019] Examples of positively charged monomers in organic liquids that can be used for coating in embodiments of the present disclosure include, but are not limited to, 2-(dimethylamino)ethyl acrylate hydrochloride, [2-(acryloyloxy)ethyl]trimethylammonium chloride, 2-aminoethyl methacrylate hydrochloride, N-(3-aminopropyl) methacrylate hydrochloride, 2-(dimethylamino)ethyl methacrylate hydrochloride, [3-(methacryloylamino)propyl]trimethylammonium chloride solution, [2-(methacryloyloxy)ethyl]trimethylammonium chloride, acrylamidopropyltrimethylammonium chloride, 2-aminoethyl methacrylamide hydrochloride, N-(2-aminoethyl)methacrylamide hydrochloride, N-(3-aminopropyl)methacrylamide hydrochloride, diallyldimethylammonium chloride, vinylbenzyltrimethylammonium chloride, allylamine hydrochloride, vinylimidazolium hydrochloride, vinylpyridinium hydrochloride, and vinylbenzyltrimethylammonium chloride, either alone or in combination of two or more. It should be understood that some of the positively charged monomers listed above contain quaternary ammonium groups and are spontaneously charged in organic solvents, while other positively charged monomers, such as those containing primary, secondary, and tertiary amines, are modified to become charged by treatment with acid. Monomers that can be spontaneously or by treatment in organic solvents can be polymerized and crosslinked with crosslinking agents to form coatings on porous films that are also positively charged when in contact with organic solvents. In certain embodiments, the positively charged monomers in organic liquids are selected from diallyldimethylammonium chloride, diallyldimethylammonium bromide, acrylamidopropyltrimethylammonium chloride (CAS No. 7398-69-8), acrylamidopropyltrimethylammonium bromide, vinylbenzyltrimethylammonium chloride (CAS No. 26616-35-3), and vinylbenzyltrimethylammonium bromide. In certain embodiments, the coatings are prepared from the polymerization of diallyldimethylammonium chloride with at least one crosslinking agent.Some of these monomers contain quaternary ammonium groups and are naturally charged in polar solvents, while other monomers with positive charges, such as those containing primary, secondary, or tertiary amines, can be adjusted to generate charges by treatment with an acid. It should also be understood that this free radical polymerization coating can be prepared using the chloride or hydrochloride form of the above monomers, can be converted to different halide or hydrogen halide forms, or can be converted to the hydroxide form prior to polymerization. Therefore, this list of monomers is intended to include variations of the associated anions, i.e., different halides or different halides. In certain embodiments, the coating is prepared from, consists of, or consists essentially of the positively charged monomers described herein (and is used in combination with one or more crosslinking agents).

[0020]

[0020] In certain embodiments, the coating on the porous PTFE membrane is prepared from positively charged polymerization monomers. It should be understood that embodiments of the present disclosure may include a plurality of polymerization monomers having different (copolymers) or the same (homopolymers) positive charges. In one embodiment, some of the plurality of polymerization monomers having positive charges are the same. In another specific embodiment, some of the plurality of polymerization monomers having positive charges are different from each other. The plurality of polymerization monomers having positive charges may have one or more properties that are different from or similar to each other. In certain embodiments of such coatings, one or more of the polymerization monomers are different from each other and form a positively charged copolymer crosslinked to other polymerization monomers by a crosslinking agent.

[0021]

[0021] Examples of negatively charged monomers in organic liquids that can be used for coating include, but are not limited to, 2-ethyl acrylic acid, acrylic acid, 2-carboxyethyl acrylate, potassium 3-sulfopropyl acrylate, 2-propyl acrylic acid, 2-(trifluoromethyl)acrylic acid, methacrylic acid, sodium 2-methyl-2-propene-1-sulfonate, mono-2-(methacryloyloxy)ethyl maleate, potassium 3-sulfopropyl methacrylate, 2-acrylamido-2-methyl-1-propanesulfonic acid, 3-methacrylamidophenylboronic acid, vinylsulfonic acid, and vinylphosphonic acid, either individually or in combination of two or more of these. In certain embodiments, the negatively charged monomers include sulfonic acids. It should be understood that some of the negatively charged monomers listed above contain strong acid groups and are spontaneously charged in organic solvents, while other negatively charged monomers containing weak acids are modified to generate charge by base treatment. Monomers that are naturally or by treatment negatively charged in organic solvents can be polymerized and crosslinked with at least one crosslinking agent to form a coating on a porous film that is negatively charged in organic solvents. In certain embodiments, the coating is prepared from monomers selected from 2-methyl-2-propene-1-sulfonate (such as sodium salt), 2-acrylamido-2-methyl-1-propanesulfonic acid, vinylsulfonic acid, and vinylphosphonic acid, or salts thereof, and at least one crosslinking agent.

[0022]

[0022] In one embodiment, the coating is prepared from a plurality of negatively charged polymer monomers. In one embodiment, the plurality of negatively charged monomers are identical. In another specific embodiment, the plurality of negatively charged monomers are different from one another. The plurality of negatively charged monomers may have one or more different or similar properties. In an embodiment of the coating, one or more negatively charged polymer monomers are crosslinked with one or more other negatively charged polymer monomers. In another embodiment, the coating can be prepared from a combination of positively charged and negatively charged polymer monomers crosslinked on the same film or on separate films. In another embodiment, a porous film is coated with crosslinked positively charged polymer monomers, and another separate porous film contains crosslinked negatively charged polymer monomers. In another embodiment, a coating of positively and negatively charged polymer monomers is crosslinked and formed on the same porous polymer film. In yet another embodiment, the coating containing crosslinked polymer monomers is amphoteric and contains monomers having both positive and negative charges on the same monomer in an organic liquid.

[0023]

[0023] Amphoteric monomers have both positive and negative charges within the same monomer backbone. Non-limiting examples of amphoteric monomers that can be polymerized and crosslinked on the surface of a film include [3-(methacryloylamino)propyl]dimethyl(3-sulfopropyl)ammonium hydroxide, [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide, 2-(methacryloyloxy)ethyl 2-(trimethylammonio)ethyl phosphate, 1-(3-sulfopropyl)-2-vinylpyridinium hydroxide, and combinations thereof.

[0024]

[0024] In further embodiments, a portion of the uncharged monomers, approximately 0 to approximately 10 weight percent, can be used in the polymerization reaction (based on the total weight of the reaction solution). Such monomers are generally ethylenically unsaturated monomers selected from acrylic acid esters, methacrylic acid esters, and vinyl compounds.

[0025]

[0025] The crosslinking agents are optionally uncharged difunctional (i.e., having two carbon-carbon double bonds) vinyl monomer species, acrylic monomer species, or methacrylic monomer species having an amide functional group. Non-limiting examples of such crosslinking agents include methylenebis(acrylamide), tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, divinyl sulfone, divinylbenzene, 98% 1,3,5-trialyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, ethylene glycol divinyl ether, divinyl polyethylene glycol, and triallylamine.

[0026]

[0026] For example, polymerization and crosslinking of polymerizable monomers onto a porous membrane substrate can be carried out such that a selected portion of the porous membrane or the entire surface including the inner surface of the porous membrane is modified with the crosslinked polymer.

[0027]

[0027] For the free radical polymerization reaction that forms the coating, the reagent bath consists of: (1) at least one polymerizable monomer that is ethylenically unsaturated and has at least one charged moiety, (2) a polymerization initiator as needed, and (3) a crosslinking agent in a polar solvent such as a water-soluble solvent for these three components, which are brought into contact with the porous polymer film substrate under conditions that result in polymerization and crosslinking of the monomers and deposition of the resulting crosslinked polymer onto the porous polymer film substrate. Even if the solvent is a polar solvent, the desired degree of film surface modification may be obtained. If the monomer is bifunctional or has higher functionality, additional crosslinking agents are not required but may be used. Typical suitable polar solvents include polyols such as 2-methyl-2,4-pentanediol, 2,4-pentanedione, glycerin, or 2,2'-thiodiethanol, amides such as formamide, dimethylformamide, dimethylacetamide, alcohols such as methanol, and solvents having a dielectric constant above 25°C at room temperature, such as nitrobenzene, 2-fluoraldehyde, acetonitrile, and 1-methylpyrrolidone. A specific solvent is selected to dissolve the crosslinking agent, monomer, and initiator (if present).

[0028]

[0028] Initiators suitable for the above-mentioned monomers and crosslinking agents can be used. For example, suitable photoinitiators include benzophenone, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, azoisopropane, or 2,2-dimethoxy-2-phenylacetophenone. Suitable thermal initiators include organic peroxides such as dibenzoyl peroxide, t-butyl hydroperoxide, cumyl peroxide, and t-butyl perbenzoate, and azo compounds such as azobisisobutyronitrile (AIBN) or 4,4,'-azobis(4-cyanovaleric acid).

[0029]

[0029] In certain embodiments, the polymerizable monomer is present in the reaction solution at a concentration of about 2% to about 20%, or about 5% to about 10%, based on the weight of the total solution. The crosslinking agent is present in an amount between about 2% and about 10%, based on the weight of the polymerizable monomer. A larger amount of crosslinking agent can be used. The polymerization initiator is present in an amount between about 1% and about 10%, based on the weight of the polymerizable monomer. As described above, the crosslinking agent can be used without the monomer and thereby function as a polymerizable monomer.

[0030]

[0030] In certain embodiments, the H of the negatively charged film of the disclosure is measured by titration of ionizable groups. + The ion exchange capacity is approximately 1 to 100, 1 to 40, or 1 to 10 meq H + / m 2 It is a membrane. (meq = milliequivalent). Similarly, the OH of positively and negatively charged membranes is measured by titration of ionizable groups. - The ion exchange capacity is approximately 1 to 100, 1 to 40, or 1 to 10 meq H + / m 2 It is a membrane.

[0031]

[0031] Polymerization and crosslinking can be achieved by exposing the monomer reaction system to ultraviolet (UV), a heat source, or ionizing radiation. Polymerization and crosslinking are carried out in an environment in which oxygen does not inhibit polymerization or crosslinking. This process can be easily carried out by immersing a film substrate in a solution containing monomers, a crosslinking agent, and an initiator, and then exposing the film to UV light by sandwiching it between two UV-transmitting sheets such as polyethylene, or between a blanket of inert gas such as nitrogen. This process can be carried out continuously, and once UV irradiation is started, the desired crosslinked coating is formed. As described above, coated films are produced by controlling the concentration of the reactants and the UV irradiation.

[0032]

[0032] Accordingly, in a further embodiment, the disclosure provides a porous membrane comprising poly(tetrafluoroethylene), wherein the membrane has a coating, the coating prepared from the polymerization of at least one monomer and at least one crosslinking agent, the monomer having a positive charge in an organic liquid. In one embodiment, the monomer is a quaternary ammonium compound having at least one carbon-carbon double bond. In another embodiment, the quaternary ammonium compound is selected from diallyldimethylammonium halides, e.g., diallyldimethylammonium chloride or diallyldimethylammonium bromide, or vinylbenzyltrimethylammonium chloride or vinylbenzyltrimethylammonium bromide. In a further embodiment, at least one monomer further comprises a monomer having a negative charge in an organic liquid.

[0033]

[0033] The membranes of the present disclosure may be used individually or as a combination or assembly of two or more membranes, if desired. As shown in the following examples, the use of a positively charged membrane and another negatively charged membrane together as a membrane assembly has shown excellent performance in removing various metal ion contaminants in various organic liquids. Therefore, in a further embodiment, the present disclosure provides a membrane assembly comprising: a. A porous membrane comprising poly(tetrafluoroethylene), having a coating on the film, wherein the coating is prepared from the polymerization of at least one monomer and at least one crosslinking agent, and the monomer has a positive charge in an organic liquid. b. A porous membrane comprising poly(tetrafluoroethylene), having a coating on the film, the coating prepared from polymerization of at least one monomer and at least one crosslinking agent, the monomer having a negative charge in an organic liquid, and Includes, The membrane assembly exhibits a total removal efficiency of over 90% of one or more metal ions selected from lithium, boron, sodium, magnesium, aluminum, potassium, calcium, titanium, vanadium, chromium, manganese, iron, nickel, copper, zinc, molybdenum, silver, tin, barium, and lead ions from a feed stream containing 1 ppb of metal ions selected from lithium, boron, sodium, magnesium, aluminum, potassium, calcium, titanium, vanadium, chromium, manganese, iron, nickel, copper, zinc, molybdenum, silver, tin, barium, and lead ions.

[0034]

[0034] Furthermore, as shown in the following embodiments, it has also been shown that in a filter device including a positive electrode film and a negative electrode film, the leaching of certain metal ions, which are thought to originate from the polymer backbone of the film, was significantly reduced. Therefore, in further embodiments, this disclosure a. The film comprises poly(tetrafluoroethylene), and the film has a coating thereon, the coating being prepared from the polymerization of at least one monomer and at least one crosslinking agent, the monomer being a positively charged porous film in an organic liquid b. A film comprising poly(tetrafluoroethylene) having a coating on the film, the coating being prepared from polymerization of at least one monomer and at least one crosslinking agent, the monomer being a porous film having a negative charge in an organic liquid It includes multiple membranes, When immersed in a PGME / PGMEA solution (70:30 by volume) for 8 hours, it generates metal ions selected from sodium, magnesium, aluminum, potassium, calcium, iron, and zinc ions at levels less than 0.080 ppb. We provide a filter device.

[0035]

[0035] It should also be understood that the methods of the present disclosure include removing metal contaminants from a set of organic liquids, which may be liquids, either individually or in combination of two or more. Non-limiting examples of organic liquids include cyclohexanone, isopentyl ether, propylene glycol monomethyl ether acetate (PGMEA), methyl isobutylcarbinol, N-butyl acetate, methyl-2-hydroxyisobutyrate, and a mixed solution of propylene glycol monomethyl ether (PGME) and PGMEA (mixing ratio 7:3, surface tension 27.7 mN / m), which may be individually or in combination of two or more. Specific embodiments include, but are not limited to, organic liquids that are immiscible with water, such as cyclohexanone and PGMEA. In one embodiment, immiscibility with water means that up to 19.8 g is soluble in water per 100 ml of water.

[0036]

[0036] Therefore, the membranes, membrane assemblies, and filter devices of the present invention are useful for removing metal ion contaminants from organic liquids. Embodiments of the present disclosure include removing metal contaminants from a combination of several different organic liquids. Specific embodiments include solvents used in photoresists. Examples of solvents used in photoresists include, but are not limited to, liquids such as methyl amyl ketone, ethyl-3-ethoxypropionate, propylene glycol methyl ether (PGME), propylene glycol methyl ether acetate (PGMEA), methanol, ethyl acetate, and ethyl lactate, which can be used alone or in combination of two or more.

[0037]

[0037] Unless otherwise specified, the methods disclosed herein are not limited by the order, frequency, or sequence of various actions or processes and can be repeated as necessary.

[0038]

[0038] As described above, this method is not limited to any order or sequence unless otherwise specified and can be repeated as needed. In another embodiment, the first membrane is a membrane having a negatively charged crosslinked monomer, and the second membrane is a membrane having a positively charged crosslinked monomer. Furthermore, a combination of positively and negatively charged polymer monomers can also be coated onto the porous polymer membrane. In another embodiment, the coating with positively and negatively charged polymer monomers is on the same membrane. In one embodiment, the first membrane of the two-layer membrane stack may include a coating with positively and negatively charged polymer monomers on the same membrane. In another embodiment, the second membrane of the two-layer membrane stack may include a coating with positively and negatively charged polymer monomers on the same membrane. Unless otherwise specified, the sequence, frequency, or order may be changed. It should be understood that the first and second membranes can effectively remove metal contaminants in different or different efficiencies from each other.

[0039]

[0039] Another embodiment includes a method for removing metal contaminants from an organic liquid by passing the organic liquid through a porous polymer membrane assembly having multiple layers. The porous polymer membrane assembly includes a first layer (or membrane) and a second layer (or membrane). The first layer includes a coating comprising one or more crosslinked polymer monomers having a positive charge. The second layer includes a coating comprising one or more crosslinked polymer monomers having a negative charge. The organic liquid has a low concentration of metal contaminants after passing through the porous polymer membrane. In certain embodiments, the organic liquid includes a liquid used for photoresist. Combinations of polymer monomers having positive and negative charges can be coated onto the layers of the polymer membrane. It should be understood that different layers of the membrane and apparatus housing the membranes can effectively remove metal contaminants with different or different efficiencies.

[0040]

[0040] In certain embodiments, the metal contaminants to be removed include Li, Na, Mg, Al, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Mo, Ag, Cd, Sn, Ba, and Pb ions, either individually or in combination of two or more. In other embodiments, metal contaminants such as Al, Ca, Cr, Cu, Fe, Pb, Mg, Mn, Ni, K, Na, Sn, Ti, and Zn are removed individually or in combination of two or more. In certain embodiments, metal contaminants such as Fe, Ni, Cr, Cu, and Al are removed individually or in combination of two or more. In one embodiment, metal contaminants such as Fe, Ni, and Cr are removed individually or in combination of two or more. In one embodiment, when an organic liquid immiscible with water is passed through a porous membrane or porous membrane assembly, and then metal contaminants are removed from the immiscible organic liquid, the removal efficiency of metal contaminants such as Al, Ca, Cr, Cu, Fe, Pb, Mg, Mn, Ni, K, Na, Sn, Ti, and Zn is approximately 90%, 92%, 95%, or 97% when removing metal contaminants from an organic liquid immiscible with water. In the example shown below, the membrane area is 1000 cm². 2 1200 ml of each liquid solution was injected into the apparatus. In certain embodiments, the removal efficiency of metal contaminants exceeds 90%, 92%, 95%, and 97%, and approaches 100%, as detailed in Table 2 below. In other words, the concentration of metal contaminants in the organic liquid supply stream for one or more of the metal species listed above is reduced by approximately 99%, 98%, 97%, 96%, 95%, 94%, 93%, 92%, 91%, 90%, or 85% of the initial supply concentration after passing through one or more coated porous PTFE membranes. In some embodiments, the concentration of metal contaminants in the organic liquid supply stream is 150 ppbv / v or less, and the removal of metal contaminants is 1000 cm² as described herein. 2 This is measured by passing an organic liquid supply stream through an apparatus containing a coated porous membrane at a flow rate of 60 milliliters per minute (ml / min) and measuring the treated discharged organic liquid. In all cases, the reference to metallic contaminants here includes both metallic (i.e., zero-valent) and ionic metallic contaminants.

[0041]

[0041] In some embodiments, as shown in Example 6 below, a filter device comprising one or more coated porous PTFE membranes generates at least one metal ion selected from sodium, magnesium, aluminum, potassium, calcium, iron, and zinc ions at a level of less than 0.080 ppb when immersed in a PGME / PGMEA solution (70:30 by volume) for 8 hours. In some embodiments, a filter device immersed for 8 hours as described above generates each metal ion selected from sodium, magnesium, aluminum, potassium, calcium, iron, and zinc ions at a level of less than 0.080 ppb.

[0042]

[0042] In another embodiment, the present invention provides a filtration device comprising one or more of the membranes of the present invention. An example of a filter structure comprising a pleated cylindrical filter membrane can be prepared to include the following components, any of which may be included in the filter structure but may not be required: a rigid or semi-rigid core supporting the pleated cylindrical coated filter membrane at an internal opening of the pleated cylindrical coated filter membrane; a rigid or semi-rigid cage supporting or surrounding the exterior of the pleated cylindrical coated filter membrane outside the pleated cylindrical coated filter membrane; optional end pieces or “packs” positioned at each of the two opposing ends of the pleated cylindrical coated filter membrane; and a filter housing comprising an inlet and an outlet. The filter housing can be of any useful and desired size, shape, and material, and can preferably be made of a suitable polymer material.

[0043]

[0043] As an example, Figure 1 shows a filter component 30 comprising a pleated cylindrical component 10, an end piece 22, and other optional components. The cylindrical component 10 includes a filter membrane 12, which is pleated, as described herein. In some embodiments, the filter membrane 12 is a membrane assembly of multiple membranes, with optional separator material placed between the individual membranes. The end piece 22 is attached to one end of the cylindrical filter component 10 (e.g., "potted"). The end piece 22 can preferably be made from a melt-workable polymer material. A core (not shown) can be placed in the internal opening 24 of the pleated cylindrical component 10, and a cage (not shown) can be placed on the outside of the pleated cylindrical component 10. A second end piece (not shown) can be attached to the second end of the pleated cylindrical component 30 ("potted"). The resulting pleated cylindrical component 30 includes two opposing potting ends and an optional core and cage, and is placed in a filter housing that includes an inlet and an outlet. This is because the entire volume of fluid flowing in from the inlet must pass through the filter membrane 12 before exiting the filter from the outlet.

[0044]

[0044] Example

[0045] Example 1

[0046] This example demonstrates a method for modifying the surface of a porous polyethylene (UPE) film with a coating containing a negatively charged polymerization monomer (a negative UPE film).

[0045]

[0047] A surface-modifying monomer solution was prepared containing the following components: 0.3% Irgacure 2959, 6% methanol, 5.6% acrylamide methylpropanesulfonic acid (AMPS), 2.5% methylenebisacrylamide (MBAm) crosslinking agent, and 85.6% water (these percentages are weight percentages based on the total weight of the polymerization solution mixture).

[0046]

[0048] The porous UPE membrane surface-modified with a coating having a polymerization monomer with a negative charge is produced by the following method. First, a disk of a 47 mm UPE porous membrane (thickness 84 μm, average bubble point 27 psi in isopropanol (IPA), Entegris, Inc.) was wetted with an IPA solution for 25 seconds. (In the bubble point test method, a sample of the porous polymer filter membrane is immersed in a liquid with known surface tension to be wetted, and gas pressure is applied to one side of the sample.) The gas pressure is gradually increased. The minimum pressure at which gas flows through the sample is called the bubble point. To determine the bubble point of the porous material, a sample of the porous material is immersed in isopropanol at a temperature of 20 - 25 °C (e.g., 22 °C) to be wetted. Compressed air is used to apply gas pressure to one side of the sample, and the gas pressure is gradually increased. Next, the membrane was washed using an exchange solution containing 10% hexylene glycol and 90% water to remove IPA. Next, the porous membrane disk was introduced into the surface-modifying monomer solution and left submerged for 2 minutes. The porous membrane disk was taken out of the surface-modifying monomer solution and placed between transparent polyethylene sheets. The excess solution was removed by rolling a rubber roller over the polyethylene / membrane disk / polyethylene sandwich placed flat on the table. Next, the polyethylene sandwich was taped to a transport unit, and the assembly was conveyed through a broad-band UV exposure experimental unit of Fusion Systems that emits wavelengths of 200 - 600 nm. The exposure time was controlled by the speed at which the assembly passed through the UV unit. In this example, the assembly was moved through the UV chamber at a speed of 10 feet per minute. After coming out of the UV unit, the membrane was taken out of the sandwich and immediately placed in DI water and immersed for 5 minutes. Next, the treated membrane sample was transferred to methanol and immersed for 5 minutes. After this immersion procedure, the membrane was dried on a holder in an oven operating at 50 °C for 10 minutes. The water flow time of the membrane modified as described above was 400 seconds / 500 mL. H + The ion exchange capacity is measured by titration of the ionizable groups and is 4.2 meq H per 1 m of the membrane 2 + ​It was determined to be hydrophilic (meq = milliequivalent). The resulting membrane is hydrophilic and will spontaneously wet when submerged in deionized water.

[0047]

[0049] Example 2

[0050] This example demonstrates a method for modifying the surface of a porous polyethylene (UPE) film with a coating containing positively charged polymerization monomers (positive UPE film). A surface modification monomer solution was prepared containing the following components: 0.3% Irgacure 2959, 10% methanol, 5.5% (3-acrylamidopropyl)trimethylammonium chloride (APTAC), 2.0% N,N-dimethylacrylamide (DMAM), 1.5% methylenebisacrylamide (MBAm) crosslinking agent, and 80.7% water.

[0048]

[0051] A porous PTFE membrane surface-modified with a coating containing negatively charged polymerization monomers is manufactured by the following method. First, a 47 mm PTFE porous membrane disc (84 μm thick, mean foaming point in IPA 27 psi) is moistened with IPA solution for 25 seconds. Next, the membrane is washed with a replacement solution containing 10% hexylene glycol and 90% water to remove the IPA. Then, the porous membrane disc is introduced into the surface-modified monomer solution and left submerged for 2 minutes. The porous membrane disc is removed from the surface-modified monomer solution and placed between transparent polyethylene sheets. Excess solution is removed by placing the polyethylene / membrane disc / polyethylene sandwich flat on a table and rolling a rubber roller over it. Next, the polyethylene sandwich is secured to a transport unit with tape, and the assembly is transported through a Fusion Systems broadband UV exposure experimental unit emitting wavelengths of 200–600 nm. The exposure time was controlled by the speed at which the assembly passed through the UV unit. In this example, the assembly was moved at a speed of 10 feet per minute within the UV chamber. After being removed from the UV unit, the membrane was taken out of the sandwich and immediately placed in DI water for 5 minutes. Next, the treated membrane sample was transferred to methanol and immersed for 5 minutes. After this immersion procedure, the membrane was dried on a holder in an oven operating at 50°C for 10 minutes. The aqueous flow time for the modified membrane as described above was 780 seconds / 500 mL. - The ion exchange capacity was measured by titration of the ionizing group, resulting in 2.5 meq OH - / m 2 It was determined to be a membrane. The obtained membrane is hydrophilic and will spontaneously wet when submerged in deionized water.

[0049]

[0052] Example 3

[0053] This embodiment describes a method for modifying the surface of a porous polytetrafluoroethylene (PTFE) film with a coating having a negatively charged polymerization monomer (negatively charged PTFE film).

[0050]

[0054] A surface-modifying monomer solution containing the following components was prepared: 0.3% Irgacure 2959, 10% methanol, 5.6% acrylamide methylpropanesulfonic acid (AMPS), 2.5% methylenebisacrylamide (MBAm) crosslinking agent, and 81.6% water (by weight).

[0051]

[0055] A porous PTFE membrane surface-modified with a coating containing negatively charged polymerization monomers is manufactured by the following method: First, a 47 mm PTFE porous membrane disc (60 μm thick, average foaming point in IPA 25 psi) is moistened with IPA solution for 25 seconds. Next, the membrane is washed with a replacement solution containing 10% hexylene glycol and 90% water to remove the IPA. Then, the porous membrane disc is introduced into the surface-modified monomer solution and left submerged for 2 minutes. The porous membrane disc is removed from the surface-modified monomer solution and placed between transparent polyethylene sheets. Excess solution is removed by placing the polyethylene / membrane disc / polyethylene sandwich flat on a table and rolling a rubber roller over it. Next, the polyethylene sandwich is secured to a transport unit with tape, and the assembly is transported through a Fusion Systems broadband UV exposure experimental unit emitting wavelengths of 200–600 nm. The exposure time was controlled by the speed at which the assembly passed through the UV unit. In this example, the assembly was moved at a speed of 10 feet per minute within the UV chamber. After being removed from the UV unit, the membrane was taken out of the sandwich and immediately placed in DI water for 5 minutes. Next, the treated membrane sample was transferred to methanol and immersed for 5 minutes. After this immersion procedure, the membrane was dried on a holder in an oven operating at 50°C for 10 minutes. The water flow time for the modified membrane as described above was 250 seconds / 500 mL. + The ion exchange capacity was measured by titration of ionized groups, and was 3.2 meq H+ / m³. 2 It was determined to be a membrane. The obtained membrane is hydrophilic and will spontaneously wet when submerged in deionized water.

[0052]

[0056] Example 4

[0057] This embodiment describes a method for modifying the surface of a porous polytetrafluoroethylene (PTFE) film with a coating having a positively charged polymerization monomer (positive PTFE film).

[0053]

[0058] A surface-modifying monomer solution containing the following components was prepared: 0.3% Irgacure 2959, 10% methanol, 4% (3-acrylamidopropyl)trimethylammonium chloride (APTAC), 4% diallyldimethylammonium chloride (DADMAC), 2.5% methylenebisacrylamide (MBAm) crosslinking agent, and 79.2% water.

[0054]

[0059] A porous PTFE membrane surface-modified with a coating containing negatively charged polymerization monomers is manufactured by the following method: First, a 47 mm PTFE porous membrane disc (60 μm thick, average foaming point in IPA 24 psi) is moistened with IPA solution for 25 seconds. Next, the membrane is washed with a replacement solution containing 10% hexylene glycol and 90% water to remove the IPA. Then, the porous membrane disc is introduced into the surface-modified monomer solution and left submerged for 2 minutes. The porous membrane disc is removed from the surface-modified monomer solution and placed between transparent polyethylene sheets. Excess solution is removed by placing the polyethylene / membrane disc / polyethylene sandwich flat on a table and rolling a rubber roller over it. Next, the polyethylene sandwich is secured to a transport unit with tape, and the assembly is transported through a Fusion Systems broadband UV exposure experimental unit emitting wavelengths of 200–600 nm. The exposure time was controlled by the speed at which the assembly passed through the UV unit. In this example, the assembly was moved at a speed of 10 feet per minute within the UV chamber. After being removed from the UV unit, the membrane was taken out of the sandwich and immediately placed in DI water for 5 minutes. Next, the treated membrane sample was transferred to methanol and immersed for 5 minutes. After this immersion procedure, the membrane was dried on a holder in an oven operating at 50°C for 10 minutes. The water flow rate for the modified membrane as described above was 370 seconds / 500 mL. -The ion exchange capacity was measured by titration of the ionized group, resulting in 3.2 meq OH - / m 2 It was determined to be a membrane. The obtained membrane is hydrophilic and will spontaneously wet when submerged in deionized water.

[0055]

[0060] Example 5: Metal removal efficiency in various photolithography solvents

[0061] This embodiment demonstrates the ability of a membrane assembly of a porous polyethylene (UPE) membrane surface-modified with a coating having a negatively charged polymerization monomer, a porous UPE membrane surface-modified with a coating having a positively charged polymerization monomer, and a porous polytetrafluoroethylene (PTFE) membrane surface-modified with a coating having a negatively charged polymerization monomer, and a porous polytetrafluoroethylene (PTFE) membrane surface-modified with a coating having a positively charged polymerization monomer, to reduce metal content in solvents commonly used in photolithography.

[0056]

[0062] Metal removal performance in different polar and nonpolar solvents, such as propylene glycol methyl ether (PGME) / propylene glycol methyl ethyl acetate (PGMEA) (70 / 30), propylene glycol methyl ethyl acetate (PGMEA), cyclohexanone (CHN), and n-butyl acetate (n-BA), was evaluated using 47 mm coupons from different purifiers, negative UPE membranes (fabricated according to Example 1), positive UPE membranes (fabricated according to Example 2), and positive PTFE membranes (fabricated according to Example 4) / negative PTFE membranes (fabricated according to Example 3). The purifying membrane assemblies were first pre-washed and then mounted in clean PFA (perfluoroalkoxy) coupon holders. Each test solvent was treated with SCP Science's Conostan® OilStandard S-21 at known concentrations (1 ppb containing 21 different metals). Samples were collected downstream of the purifying membrane assemblies at 50 mL, 100 mL, and 150 mL volume intervals. The feed samples and filtrate samples were analyzed using an Agilent ICPMS 8900 to evaluate the metal removal performance of the three purification systems. The results are shown in Tables 1a-1d as removal rates (%) for individual metals, and in Table 2 for all metals. From the data below, the positive PTFE / negative PTFE membrane demonstrates performance equivalent to or better than the negative and positive UPE membranes for all metals in all tested solvents. Table 2 summarizes the average total metal removal efficiency in various solvents commonly used in photolithography. While the positive UPE membrane can remove a subset of metals from various solvents, and the negative UPE membrane can also remove a subset of metals from various solvents, the positive PTFE / negative PTFE membrane metal purification membrane assembly can achieve removal efficiencies exceeding 90% across a wide range of solvent polarities.

[0057]

[0063] Total metal concentration (1 ppb spike for each metal) in 150 ml of filtrate

[0064] Table 1a PGME / PGMEA (70 / 30; volume: volume) TIFF2026067855000002.tif111170

[0058]

[0065] Table 1b PGMEA TIFF2026067855000003.tif111170

[0059]

[0066] Table 1c n-butyl acetate TIFF2026067855000004.tif111170

[0060]

[0067] Table 1d Cyclohexanone TIFF2026067855000005.tif111170

[0061]

[0068] Table 2: Comparison of metal removal efficiency of negative UPE film, positive UPE film, and positive PTFE film / Negative PTFE film TIFF2026067855000006.tif51170

[0062]

[0069] As shown in the table above, the combination of positive and negative PTFE films showed unexpectedly superior metal removal efficiency and total metal removal efficiency compared to UPE films.

[0063]

[0070] Example 6: Idle immersion investigation

[0071] New assemblies of a negative UPE membrane (fabricated according to Example 1) and a positive PTFE membrane (fabricated according to Example 4) / negative PTFE membrane (fabricated according to Example 3) were placed in an Optimizer® D capsule (Entegris, Inc.) format and immersed in PGME / PGMEA (70 / 30). They were left idle for a set period (1 hour, 8 hours, and 24 hours) to investigate metal leaching from the idle purifiers. Both purifiers were filled with solvent and left immersed for the first hour. After 1 hour, samples were taken for ICPMS analysis. Next, both lines and the Optimizer D were emptied and refilled with a new blend of PGME / PGMEA (70 / 30), and left immersed for 8 hours, and finally for 24 hours. Samples were tested using Agilent ICPMS 8900. Table 3 below shows the time-dependent metal leaching behavior between a negative UPE film and a positive / negative PTFE film when removing metal ions of Na, Mg, Al, K, Ca, Fe, and Zn under idle immersion conditions in PGME / PGMEA(70 / 30). The negative UPE film shows significantly higher metal levels at 1 hour compared to the positive / negative PTFE film for common metals such as Fe, Zn, and Ca. In the case of the negative UPE film, metal leaching appears to continue even after 24 hours of immersion, but in the case of the positive / negative PTFE film, no further metal leaching behavior is observed over time, with the same levels of metal being seen from 1 hour to 8 hours and up to 24 hours.

[0064]

[0072] Table 3: TIFF2026067855000007.tif47170

[0065]

[0073] As shown in Table 3, the combination of positive and negative PTFE films exhibited unexpectedly better overall leaching behavior than the UPE film.

[0066]

[0074] manner

[0075] In the first embodiment, this disclosure is, a. A porous membrane comprising poly(tetrafluoroethylene), wherein the film has a coating thereon, the coating being prepared from the polymerization of at least one monomer and at least one crosslinking agent, the monomer having a positive charge in an organic liquid, b. A film comprising poly(tetrafluoroethylene), wherein the film has a coating thereon, the coating being prepared from the polymerization of at least one monomer and at least one crosslinking agent, the monomer being a porous film having a negative charge in an organic liquid It includes multiple membranes, The present invention provides a membrane assembly that exhibits a total removal efficiency of over 90% of one or more metal ions selected from lithium, boron, sodium, magnesium, aluminum, potassium, calcium, titanium, vanadium, chromium, manganese, iron, nickel, copper, zinc, molybdenum, silver, tin, barium, and lead ions from a feed stream containing 1 ppb of a metal ion selected from lithium, boron, sodium, magnesium, aluminum, potassium, calcium, titanium, vanadium, chromium, manganese, iron, nickel, copper, zinc, molybdenum, silver, tin, barium, and lead ions.

[0067]

[0076] In a second aspect, the disclosure provides an assembly of the first aspect which exhibits an overall removal efficiency of more than 90% for all metal ions selected from lithium, boron, sodium, magnesium, aluminum, potassium, calcium, titanium, vanadium, chromium, manganese, iron, nickel, copper, zinc, molybdenum, silver, tin, barium, and lead ions.

[0068]

[0077] In a third aspect, the disclosure provides an assembly of the first or second aspect, wherein the metal ion is selected from iron, nickel, chromium, copper, and aluminum Al ions.

[0069]

[0078] In a fourth embodiment, the disclosure provides an assembly according to the first or second embodiment, wherein the metal ion is selected from manganese ions, magnesium ions, and zinc ions.

[0070]

[0079] In a fifth embodiment, the Disclosure provides an assembly according to the first, second, or third embodiment, wherein the metal ion is selected from iron ions, nickel ions, and chromium ions.

[0071]

[0080] In a sixth embodiment, the disclosure provides an assembly according to the first, second, or fourth embodiment, wherein the metal ion is a manganese ion.

[0072]

[0081] In a seventh embodiment, the disclosure provides an assembly according to the first, second, or fourth embodiment, wherein the metal ion is a magnesium ion.

[0073]

[0082] In an eighth aspect, the disclosure provides an assembly of the first, second, or third aspect, wherein the metal ion is a zinc ion.

[0074]

[0083] In a ninth aspect, the disclosure provides an assembly of any of the above embodiments, wherein the monomer having a positive charge in the organic liquid is a quaternary ammonium compound having at least one carbon-carbon double bond.

[0075]

[0084] In a tenth embodiment, the disclosure provides an assembly of the ninth embodiment, wherein the quaternary ammonium compound is selected from diallyldimethylammonium chloride, diallyldimethylammonium bromide, vinylbenzyltrimethylammonium chloride, and vinylbenzyltrimethylammonium bromide.

[0076]

[0085] In an eleventh aspect, the Disclosure provides an assembly of any of the above-described embodiments, wherein the crosslinking agent is selected from methylenebis(acrylamide), tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, divinyl sulfone, divinylbenzene, 98% 1,3,5-trialyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, ethylene glycol divinyl ether, divinyl polyethylene glycol, and triallylamine.

[0077]

[0086] In a twelfth aspect, the present disclosure provides an assembly of any of the aforementioned embodiments, wherein the supply stream comprises a PGME / PGMEA solution (70:30 by volume), PGMEA, n-butyl acetate, or cyclohexanone.

[0078]

[0087] In a thirteenth embodiment, the Disclosure provides a filter device including an assembly of any of the embodiments described above.

[0079]

[0088] In the 14th embodiment, this disclosure is: a. The film comprises poly(tetrafluoroethylene), and the film has a coating thereon, the coating being prepared from the polymerization of at least one monomer and at least one crosslinking agent, the monomer being a positively charged porous film in an organic liquid b. A film comprising poly(tetrafluoroethylene) having a coating on the film, the coating being prepared from polymerization of at least one monomer and at least one crosslinking agent, the monomer being a porous film having a negative charge in an organic liquid It includes multiple membranes, The present invention provides a filter device that, when immersed in a PGME / PGMEA solution (70:30 by volume) for 8 hours, generates at least one metal ion from among sodium, magnesium, aluminum, potassium, calcium, iron, and zinc ions at a level of less than 0.080 ppb.

[0080]

[0089] In a 15th aspect, the present disclosure provides a filter apparatus according to a 14th aspect, wherein the positively charged monomer is a quaternary ammonium compound having at least one carbon-carbon double bond.

[0081]

[0090] In a sixteenth embodiment, the disclosure provides a filter apparatus according to a fifteenth embodiment, wherein the quaternary ammonium compound is selected from diallyldimethylammonium chloride, diallyldimethylammonium bromide, vinylbenzyltrimethylammonium chloride, and vinylbenzyltrimethylammonium bromide.

[0082]

[0091] In a 17th embodiment, the Disclosure provides a filter apparatus according to any of the 14th to 16th embodiments, wherein the crosslinking agent is selected from methylenebis(acrylamide), tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, divinyl sulfone, divinylbenzene, 98% 1,3,5-trialyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, ethylene glycol divinyl ether, divinyl polyethylene glycol, and triallylamine.

[0083]

[0092] In the eighteenth aspect, the disclosure provides a filtering apparatus according to any of the fourteenth to seventeenth aspects, which generates metal ions of sodium, magnesium, aluminum, potassium, calcium, iron, and zinc at levels below 0.080 ppb.

[0084]

[0093] In a 19th aspect, the Disclosure provides a porous membrane comprising poly(tetrafluoroethylene), wherein the membrane has a coating, the coating being prepared from the polymerization of at least one monomer and at least one crosslinking agent, the monomer having a positive charge in an organic liquid, and the monomer being a quaternary ammonium compound having at least one carbon-carbon double bond.

[0085]

[0094] In a 20th aspect, the disclosure provides a film according to a 19th aspect, wherein the quaternary ammonium compound is selected from diallyldimethylammonium chloride, diallyldimethylammonium bromide, vinylbenzyltrimethylammonium chloride, and vinylbenzyltrimethylammonium bromide.

[0086]

[0095] In a 21st embodiment, the Disclosure provides a film according to a 19th or 20th embodiment, further comprising at least one monomer having a negative charge in an organic liquid.

[0087]

[0096] In a 22nd aspect, the Disclosure provides a film of any of the 19th to 21st aspects, wherein the monomer having a negative charge in an organic liquid is selected from 2-ethylacrylic acid, acrylic acid, 2-carboxyethyl acrylate, potassium 3-sulfopropyl acrylate, 2-propylacrylic acid, 2-(trifluoromethyl)acrylic acid, methacrylic acid, sodium 2-methyl-2-propene-1-sulfonate, mono-2-(methacryloyloxy)ethyl maleate, potassium 3-sulfopropyl methacrylate, 2-acrylamido-2-methyl-1-propanesulfonic acid, 3-methacrylamidophenylboronic acid, vinylsulfonic acid, acrylamidemethylpropanesulfonic acid, and vinylphosphonic acid.

[0088]

[0097] In a 23rd aspect, the disclosure provides a film of a 22nd aspect, wherein the monomer having a negative charge in the organic liquid is acrylamidemethylpropanesulfonic acid.

[0089]

[0098] In a 24th embodiment, the Disclosure provides a filter device comprising a membrane according to any of the 19th to 23rd embodiments.

[0090]

[0099] In a 25th aspect, the Disclosure provides a method for removing a metallic contaminant from an organic liquid, the method comprising passing the liquid through (i) a membrane assembly of any one of the 1st to 12th aspects, (ii) a filter device of any one of the 13th to 18th aspects, or (iii) a membrane of any one of the 19th to 23rd aspects.

[0091]

[0100] While several exemplary embodiments of this disclosure have been described above, those skilled in the art will readily understand that further embodiments can be created and used within the scope of the claims appended herein. Many of the advantages of the disclosures covered in this document have been stated above. However, it will be understood that in many respects this disclosure is merely illustrative. Naturally, the scope of the disclosure is defined in the language in which the appended claims are expressed.

Claims

1. a. A porous membrane containing poly(tetrafluoroethylene), wherein the membrane has a coating thereon, the coating being prepared from the polymerization of at least one monomer and at least one crosslinking agent, the monomer having a positive charge in an organic liquid, and the porous membrane, b. A porous membrane comprising poly(tetrafluoroethylene), wherein the membrane has a coating thereon, the coating being prepared from the polymerization of at least one monomer and at least one crosslinking agent, the monomer having a negative charge in an organic liquid, and the porous membrane and Includes, A membrane assembly exhibiting a total removal efficiency of over 90% of one or more metal ions selected from lithium, boron, sodium, magnesium, aluminum, potassium, calcium, titanium, vanadium, chromium, manganese, iron, nickel, copper, zinc, molybdenum, silver, tin, barium, and lead ions from a feedstream containing 1 ppb of metal ions selected from lithium, boron, sodium, magnesium, aluminum, potassium, calcium, titanium, vanadium, chromium, manganese, iron, nickel, copper, zinc, molybdenum, silver, tin, barium, and lead ions.

2. The assembly according to claim 1, exhibiting a total removal efficiency of more than 90% for all metal ions selected from lithium, boron, sodium, magnesium, aluminum, potassium, calcium, titanium, vanadium, chromium, manganese, iron, nickel, copper, zinc, molybdenum, silver, tin, barium, and lead ions.

3. The assembly according to claim 1 or 2, wherein the metal ion is selected from iron ions, nickel ions, chromium ions, copper ions, and aluminum Al ions.

4. The assembly according to claim 1 or 2, wherein the metal ion is selected from manganese ions, magnesium ions, and zinc ions.

5. The assembly according to claim 1 or 2, wherein the metal ion is selected from iron ions, nickel ions, and chromium ions.

6. The assembly according to any one of claims 1 to 5, wherein the monomer having a positive charge in the organic liquid is a quaternary ammonium compound having at least one carbon-carbon double bond.

7. The assembly according to claim 6, wherein the quaternary ammonium compound is selected from diallyldimethylammonium chloride, diallyldimethylammonium bromide, vinylbenzyltrimethylammonium chloride, and vinylbenzyltrimethylammonium bromide.

8. The assembly according to any one of claims 1 to 7, wherein the crosslinking agent is selected from methylenebis(acrylamide), tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, divinyl sulfone, divinylbenzene, 98% 1,3,5-trialyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, ethylene glycol divinyl ether, divinyl polyethylene glycol, and triallylamine.

9. The assembly according to any one of claims 1 to 8, wherein the supply stream comprises a PGME / PGMEA solution (70:30 by volume), PGMEA, n-butyl acetate, or cyclohexanone.

10. A filter device comprising the assembly according to any one of claims 1 to 9.

11. A filter device comprising multiple membranes, a. A porous membrane containing poly(tetrafluoroethylene), wherein the membrane has a coating thereon, the coating being prepared from the polymerization of at least one monomer and at least one crosslinking agent, the monomer having a positive charge in an organic liquid, and the porous membrane, b. A porous membrane comprising poly(tetrafluoroethylene), wherein the membrane has a coating thereon, the coating being prepared from the polymerization of at least one monomer and at least one crosslinking agent, the monomer having a negative charge in an organic liquid, and the porous membrane and Includes, A filter device that, when immersed in a PGME / PGMEA solution (70:30 by volume) for 8 hours, produces at least one metal ion selected from sodium, magnesium, aluminum, potassium, calcium, iron, and zinc ions at a concentration of less than 0.080 ppb.

12. The filter apparatus according to claim 11, wherein the positively charged monomer is a quaternary ammonium compound having at least one carbon-carbon double bond.

13. The filter apparatus according to claim 12, wherein the quaternary ammonium compound is selected from diallyldimethylammonium chloride, diallyldimethylammonium bromide, vinylbenzyltrimethylammonium chloride, and vinylbenzyltrimethylammonium bromide.

14. The filter apparatus according to any one of claims 11 to 13, wherein the crosslinking agent is selected from methylenebis(acrylamide), tetraethylene glycol diacrylate, tetraethylene glycol dimethacrylate, divinyl sulfone, divinylbenzene, 98% 1,3,5-trialyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, ethylene glycol divinyl ether, divinyl polyethylene glycol, and triallylamine.

15. A filter apparatus according to any one of claims 11 to 14, which generates metal ions of less than 0.080 ppb from sodium, magnesium, aluminum, potassium, calcium, iron, and zinc ions.

16. A porous membrane containing poly(tetrafluoroethylene), The film has a coating, The coating is prepared from the polymerization of at least one monomer and at least one crosslinking agent. The monomer has a positive charge in the organic liquid. The monomer is a quaternary ammonium compound having at least one carbon-carbon double bond. Porous membrane.

17. The film according to claim 16, wherein the quaternary ammonium compound is selected from diallyldimethylammonium chloride, diallyldimethylammonium bromide, vinylbenzyltrimethylammonium chloride, vinylbenzyltrimethylammonium chloride, and vinylbenzyltrimethylammonium bromide.

18. The film according to claim 17, further comprising at least one monomer having a negative charge in an organic liquid.

19. The film according to any one of claims 16 to 18, wherein the monomer having a negative charge in the organic liquid is selected from 2-ethylacrylic acid, acrylic acid, 2-carboxyethyl acrylate, potassium 3-sulfopropyl acrylate, 2-propylacrylic acid, 2-(trifluoromethyl)acrylic acid, methacrylic acid, sodium 2-methyl-2-propene-1-sulfonate, mono-2-(methacryloyloxy)ethyl maleate, potassium 3-sulfopropyl methacrylate, 2-acrylamido-2-methyl-1-propanesulfonic acid, 3-methacrylamidophenylboronic acid, vinylsulfonic acid, acrylamidemethylpropanesulfonic acid, and vinylphosphonic acid.

20. The film according to claim 19, wherein the monomer having a negative charge in the organic liquid is acrylamidemethylpropanesulfonic acid.

21. A filter apparatus comprising a membrane according to any one of claims 16 to 20.

22. A method for removing a metal contaminant from an organic liquid, comprising passing the liquid through (i) a membrane assembly according to any one of claims 1 to 9, (ii) a filter device according to any one of claims 10 to 15 and 21, or (iii) a membrane according to any one of claims 16 to 20.

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