JP2019188318A - Method for producing anion exchange resin - Google Patents

Abstract

To provide a method for producing an anion exchange resin, such as a chromate ion, having more excellent anion adsorption ability.SOLUTION: A method for producing an anion exchange resin includes: an immersion step of immersing a fibrous base material in a monomer solution containing a monomer having a halogenated hydrocarbon portion; a graft polymerization step of irradiating the base material immersed in the monomer solution with ionizing radiation, and graft polymerizing the base material with the monomer to obtain a graft polymerization base material; and a modification step of modifying the graft polymerization base material with tertiary amine. The base material has one or more forms selected from the group consisting of a fibrous shape as it is, a yarn shape formed by twisting a fiber, a bundle shape formed by bundling a fiber or a yarn formed by twisting, a hank shape formed by bundling a fiber or a yarn formed by twisting, and a chenille cord shape formed by bundling a fiber or a yarn formed by twisting.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for producing an anion exchange resin.

  Conventionally, a method for removing hexavalent chromium from wastewater has been developed in order to reduce the environmental load caused by hexavalent chromium that can be contained in the wastewater of a plating factory, the wastewater of a site where cement is used, or the mine wastewater.

  The most known method for removing hexavalent chromium includes, for example, a method of reducing hexavalent chromium to trivalent chromium having a very low environmental load by treatment with a reducing agent. However, the processing of the reducing agent requires a dedicated equipment and the process is complicated. Moreover, it is difficult to apply such a reducing agent treatment to wastewater that flows out naturally, such as mine wastewater. Furthermore, it is not easy to treat sludge generated in this reduction step.

  In Patent Document 1, after adjusting the wastewater containing hexavalent chromium to pH 1 to 6, an aqueous ferrous salt solution is added so that the oxidation-reduction potential (ORP) is maintained in the range of +100 to −100 mV. A method for removing hexavalent chromium is disclosed, in which a reduction treatment is performed such that the pH value is maintained within a range of ± 0.5 with respect to the pH value adjusted as described above. However, the method of the cited document 1 has a problem that it requires large-scale equipment and highly accurate pH control.

  On the other hand, even in sites that do not have facilities for reducing hexavalent chromium, in order to remove hexavalent chromium from wastewater efficiently, reduction to trivalent chromium is not required, and hexavalent chromium is removed in a short time. Hexavalent chromium adsorbents that can be adsorbed at low temperatures have been proposed.

  For example, Patent Document 2 introduces a hexavalent chromium recovery material using natural products such as red pine and acacia bark and leaves, and a functional group that adsorbs a metal by radiation graft polymerization using a polysaccharide such as cellulose as a base material. Adsorbents have been reported. However, since these adsorbents use sugar as a base material and have biodegradability, there is a problem in durability when used outdoors for a long period of time.

  In addition, Patent Document 3 reports a hexavalent chromium adsorbent using an inorganic material as a base material, but there is no chemical bond between the base material and the adsorbing group, so there is a problem in durability. .

  By the way, it is desirable to use a general-purpose resin such as polyolefin having both economy and durability as a base material from the viewpoint of improving the economy and durability of the adsorbent. However, few hexavalent chromium adsorbents that can efficiently recover hexavalent chromium using a general-purpose resin as a base material have been proposed.

  As an example of a method for producing an anion adsorbent such as hexavalent chromium (chromate ion) based on a general-purpose resin, Patent Document 4 discloses graft polymerization of glycidyl methacrylate (GMA) and triethylenediamine after hydrochloric acid treatment. The production method for modifying is shown. This manufacturing method is a four-step process in which a base material is irradiated with ionizing radiation to generate radicals, then GMA is graft-polymerized, treated with hydrochloric acid, and then modified with triethylenediamine. Although chloromethylstyrene has been introduced as a monomer having a chloro group, it has been shown that a purification process for removing the polymerization inhibitor is necessary, and it is not suitable for mass production due to an increase in manufacturing processes.

  In contrast, in Patent Document 5, the applicant irradiates a polymer substrate immersed in a monomer solution containing a halogenated hydrocarbon moiety with ionizing radiation to form a graft polymer chain on the polymer substrate. Later, it was reported that an anion exchange resin was obtained by modifying the graft polymer chain with a tertiary amine. In such a method, irradiation with ionizing radiation and graft polymerization are simultaneously performed, so that the number of steps in the production process can be omitted.

  The anion exchange resin obtained by such a method has an excellent adsorption performance, but an anion exchange resin having a better adsorption ability is required.

JP-A-6-304578 JP 2011-120973 A Japanese Patent Publication No. 61-52741 JP2015-39698A JP 2017-25316 A

Junichi Saito, Kunio Fujiwara, Takanobu Sugo, “Revolution of polymer adsorbents by graft polymerization”, Maruzen Publishing, 2014

  An object of the present invention is to provide a method for producing an anion exchange resin having more excellent anion adsorption ability such as chromate ion.

  The inventors of the present invention have made extensive studies to achieve the above-described object. As a result, by using a specific monomer solution, a base material is immersed in the monomer solution, and then a method for producing an anion exchange resin in which a tertiary amine is added to a graft polymerization base material that can be irradiated with ionizing radiation. The resulting anion exchange resin has a high anion adsorption ability, and when a fibrous material is used as the base material, the anion exchange resin becomes non-uniform due to the shape of the fiber, making the anion exchange resin more efficient. And as a fibrous base material, as a fibrous base material, as a fibrous form, a twisted form of a fiber, a bundle of bundles of fibers or twisted fibers, or a yarn of twisted fibers or fibers By using a morse cord composed of fiber or a thread cord composed of fibers or twisted fibers to reduce such non-uniformity. It found to be able to produce a resin efficiently, and completed the present invention. More specifically, the present invention provides the following.

  (1) The first invention of the present invention is a dipping step of immersing a fibrous base material in a monomer solution containing a monomer having a halogenated hydrocarbon moiety, and an ionizing property to the base material immersed in the monomer solution. And a graft polymerization step of obtaining a graft polymerization substrate by irradiating radiation and graft-polymerizing the monomer onto the substrate, and a modification step of modifying a tertiary amine on the graft polymerization substrate, Is a fiber shape as it is, a yarn shape formed by twisting fibers, a bundle shape formed by bundling fibers or yarns twisted, a cake shape composed of fibers or fibers formed by twisting fibers, and fibers or fibers It is a manufacturing method of the anion exchange resin which is one or more states selected from the group which consists of the shape of a mole cord comprised from the thread | yarn twisted.

  ADVANTAGE OF THE INVENTION According to this invention, the method of manufacturing an anion exchange resin with more excellent anion adsorption ability, such as chromate ion, can be provided.

It is a schematic diagram of reaction in manufacture of an anion exchange resin.

  Hereinafter, specific embodiments of the present invention (hereinafter referred to as “present embodiments”) will be described, but the present invention is not limited to the following embodiments, and the scope of the present invention is not changed. Changes can be made as appropriate.

<< 1. Anion exchange resin >>
The anion exchange resin according to the present embodiment is a resin that can efficiently recover anions from waste liquid containing anions. Specifically, the anion exchange resin is composed of a fibrous base material that is a polymer material and a graft chain.

[Base material]
In the anion exchange resin according to the present embodiment, the base material is not particularly limited, and various organic polymer materials can be used. Specifically, for example, general-purpose resins such as low density polyethylene, high density polyethylene, polypropylene, polystyrene, polyvinyl alcohol, polyvinyl chloride, polyvinylidene fluoride, polyester, polyamide, and polyurethane can be used. In particular, polyethylene, polypropylene, polyester, and polyamide are preferably used in that an anion exchange resin that is inexpensive and has a small environmental load can be obtained. From the viewpoint that the anion exchange resin is used in water, it is more preferable to use polyamide from the viewpoint that an anion exchange resin having high strength and high hydrophilicity can be obtained.

For example, the polyethylene used for the substrate is not particularly limited as long as it has a polyethylene structure as a main skeleton, but is preferably a low-density polyethylene having low crystallinity in that the graft ratio described later can be increased. Here, the low density polyethylene is based on the former JIS K6748: 1995, and means a polyethylene having a density of 0.910 g / cm ³ or more and less than 0.930 g / cm ³ . Moreover, as polyethylene used for a base material, what consists only of polyethylene and the thing containing another component can be used as long as it does not have a bad influence on adsorption | suction performance.

  The polyamide used for the substrate is not particularly limited as long as it has a polyamide structure as a main skeleton, and examples thereof include nylon. Among them, it is preferable to use a polyamide having a crystallinity of 20 to 60% in that the graft ratio described later can be increased. Here, the crystallinity refers to a value measured by a thermal analysis method, an X-ray diffraction method or the like. Moreover, as a polyamide used for a base material, as long as it does not have a bad influence on adsorption | suction performance, what consists of other components can be used.

  Moreover, the shape of the base material is not particularly limited, and a woven fabric, a nonwoven fabric, a braid or the like manufactured by weaving the yarn composed of the fibers and the yarn can be used. In the production method described later, an anion exchange resin is produced by subjecting a fibrous substrate having a specific state to a graft polymerization treatment and a tertiary amine treatment, but the state of the substrate is the production of the anion exchange resin. It is only necessary to have such a shape at the time, and after that, it may be further processed to form, for example, a thread, a woven fabric, a non-woven fabric, a braided string or the like.

[Graft chain]
In the anion exchange resin according to the present embodiment, the graft chain includes a hydrocarbon moiety and a halogenated quaternary ammonium salt moiety.

(Hydrocarbon site)
The hydrocarbon site mainly forms the skeleton of the graft chain. Although not an essential aspect, the hydrocarbon moiety preferably has a benzene ring moiety or a benzene derivative moiety. Since the monomer constituting the graft chain has such a site, the graft polymerization reaction can be efficiently advanced even by simultaneous irradiation.

(Halogenated quaternary ammonium salt moiety)
The halogenated quaternary ammonium salt moiety is a moiety having an anion adsorption ability. A graft chain containing a halogenated quaternary ammonium salt can be synthesized by adding a tertiary amine to a halogen atom of a halogenated hydrocarbon polymer.

  Examples of the tertiary amine added to the graft chain include trimethylamine, N, N′-dimethylethylamine, N, N′-dimethylisopropylamine, N, N, N ′, N′-tetramethyldiaminomethane, tris ( Dimethylamino) methane, N, N′-diethylmethylamine, N, N′-tetramethylethylenediamine, N, N′-dimethylethylenediamine, N, N, N ′, N ″, N ″ -pentamethyldiethylenetriamine, Triethylamine, N, N, N ′, N′-tetramethyl-1,3-diaminopropane, N, N, N′-trimethylethylenediamine, tris [2- (dimethylamino) ethyl] amine, N-butyldimethylamine, N, N′-diisopropylethylamine, triethylenediamine, N, N′-dimethylpipera It can be used down the like. Among them, triethylenediamine is preferable because of its high anion exchange ability.

  In the anion exchange resin according to the present embodiment, it is preferable that a monomer containing a halogenated hydrocarbon moiety is directly graft-polymerized on a base material, and then a tertiary amine is added to the graft chain by a Mentokin reaction. Although details will be described later, a simultaneous irradiation method is preferably used in the graft polymerization.

  The ratio of the graft chain in the anion exchange resin is not particularly limited, but the graft ratio calculated by the following formula (1) is preferably 10% or more, more preferably 30% or more. preferable. By setting the graft ratio of the anion exchange resin to 10% or more, the anion exchange resin can effectively adsorb the anion. By setting the graft ratio of the anion exchange resin to 30% or more, the saturated adsorption amount of the anion exchange resin with respect to the anion can be increased. On the other hand, the graft ratio is preferably 200% or less, and more preferably 150% or less. In addition, when the graft ratio of the anion exchange resin exceeds 200%, the effect of improving the anion adsorption ability is small, and the strength of the resin may be lowered.

Graft ratio (%) = ((W _g −W ₀ ) / W ₀ ) × 100 (1)
Here, W _g is the mass of the graft polymerized base material obtained by graft polymerization of a monomer containing a halogenated hydrocarbon moiety to the base material, and W ₀ is the mass of the base material (before graft polymerization) used as a raw material. .

The anion that can be adsorbed by the anion exchange resin is not particularly limited. Each anion has a negative charge and is attracted to the positive charge on the nitrogen atom of the halogenated quaternary ammonium salt described above. Therefore, any anion can be adsorbed, and in particular, a chromate ion (CrO ₄ ^2- ) and dichromate ions (Cr ₂ O ₇ ²⁻ ) can be efficiently adsorbed. Examples of the anion include chromate ion (CrO ₄ ²⁻ ) and dichromate ion (Cr ₂ O ₇ ²⁻ ), for example, sulfate ion, hydroxide ion, halide ion, nitrate ion, nitrous acid. Examples include ions, acetate ions, carbonate ions, hydrogen carbonate ions, hypochlorite ions, chlorite ions, chlorate ions, perchlorate ions, cyanide ions, phosphate ions, and the like. Hereinafter, chromate ions (CrO ₄ ²⁻ ) and dichromate ions (Cr ₂ O ₇ ²⁻ ) are referred to as “hexavalent chromium” or “Cr ⁶⁺ ”.

≪2. Method for producing anion exchange resin >>
The anion exchange resin according to the present embodiment grafts a monomer containing a halogenated hydrocarbon moiety onto a fibrous base material by irradiation with ionizing radiation, and then forms a halogen part of the graft polymer by a Menstkin reaction. It can be prepared by adding a tertiary amine. At this time, in the present embodiment, as a base material, as a base material, a fiber shape obtained by twisting fibers, a bundle shape obtained by bundling fibers or fibers, and a fiber or fibers twisted It is characterized by using a crushed shape composed of yarn or a molding cord shape composed of fibers or twisted fibers.

  FIG. 1 is a diagram schematically showing an outline of the production process of an anion exchange resin. In the example shown in FIG. 1, low-density polyethylene (LDPE) is used as a base material that is a polymer material, 4- (chloromethyl) styrene is used as a monomer containing a halogenated hydrocarbon moiety, and tertiary amine is used as a tertiary amine. Although the case of using triethylenediamine is shown, it is not limited to this.

  In the method for producing an anion exchange resin according to the present embodiment, a yarn solution, a fiber or a fiber formed by twisting a fiber as it is as a fibrous base material in a monomer solution containing a monomer having a halogenated hydrocarbon moiety Dipped in bundles made by bundling yarns made by twisting yarns, caskets made from fibers or yarns made by twisting fibers, or moldings made from yarns made by twisting fibers or fibers Immersion step (I), a graft polymerization step (II) in which a base material immersed in a monomer solution is irradiated with ionizing radiation to graft polymerize the monomer to obtain a graft polymerization base material, and the obtained graft polymerization group Modifying step (IV) for modifying the material with a tertiary amine. Further, a washing step (III) for washing the graft polymerization substrate with a Lewis basic organic solvent can be provided between the graft polymerization step (II) and the modification step (IV).

[Dipping process (I)]
The immersion step (I) is a step of immersing the base material in a monomer solution containing a monomer having a halogenated hydrocarbon moiety. Thus, the graft polymerization reaction in the subsequent graft polymerization step (II) can be rapidly advanced by immersing the substrate in the monomer solution and bringing the monomer molecules into contact with the surface of the substrate.

  At this time, the fibrous base material is composed of a fiber as it is, a yarn formed by twisting a fiber, a bundle formed by bundling fibers or fibers, or a yarn formed by twisting fibers or fibers. A crushed shape, or a Mole cord shape composed of fibers or yarns made by twisting fibers is used. In the fibrous base material having such a shape, the monomer solution is continuously supplied even between and inside the fibers. Therefore, in the subsequent graft polymerization step (II), graft polymer chains are uniformly formed throughout the fiber. Thus, an anion exchange resin having a uniform anion exchange ability over the entire fiber can be produced.

  Here, “cassette” and “mole cord” are fiber states generally used when handling a large amount of fibers (for example, several hundred kg to several t). In addition to these, there are states such as “cheese” as a state used when handling a large amount of fibers. Although details will be described later, the simultaneous irradiation graft polymerization method requires operations in each step such as immersion in a reaction solution, washing, etc. Can be increased.

  A “cassette” is a bundle of yarns of a certain length wound around a certain frame. Although it sometimes refers to an H-shaped or X-shaped tool that winds up the spun yarn, it refers to a bundle of yarn removed from the tool. Bulk per fiber weight is higher than cheese. Further, since no tension is applied to the fiber, the reaction solution easily spreads over the fiber. Note that “cheese” is obtained by winding a thread around a cylindrical core material called a bobbin while applying tension.

  “Mole cord” (mole) is a braided string made of fine fibers or a special loop structure. Mole cord has a special loop structure made of fine fibers, and collects soil particles (suspended solids (SS)) in muddy water such as rivers, lakes, and dams to purify the water. It is used to Therefore, if a fiber having an anion-adsorbing ability is used to form a molding cord, it can be adsorbed by the anion-adsorbing ability of the fiber itself, and at the same time, SS can be collected by the SS-capturing ability of a special loop structure.

  The base material that is a polymer material is not particularly limited, and as described above, low density polyethylene, high density polyethylene, polypropylene, polystyrene, polyvinyl alcohol, polyvinyl chloride, polyvinylidene fluoride, polyester (polyethylene terephthalate, etc.), General-purpose resins such as polyamide (nylon, etc.) and polyurethane can be used.

  Although it does not specifically limit as a monomer containing a halogenated hydrocarbon site | part, The monomer containing a benzene ring site | part is preferable and the monomer containing a vinylbenzyl site | part is more preferable at the point which can advance graft polymerization efficiently. Specifically, for example, 2- (chloromethyl) styrene, 3- (chloromethyl) styrene, 4- (chloromethyl) styrene, 2- (bromomethyl) styrene, 3- (bromomethyl) styrene, 4- (bromomethyl) Selected from styrene, 2- (iodomethyl) styrene, 3- (iodomethyl) styrene, 4- (iodomethyl) styrene, 2- (fluoromethyl) styrene, 3- (fluoromethyl) styrene, 4- (fluoromethyl) styrene and the like One or more monomers can be used. Among these, 4- (chloromethyl) styrene is preferably used from the viewpoint of the reactivity of the graft polymerization reaction and the anion exchange ability due to the three-dimensional structure of the graft chain.

  Such a monomer forms a graft chain by a polymerization reaction in the next graft polymerization step (II), and the formed graft chain has a number of halogen elements derived from the monomer. This halogen element reacts with a tertiary amine by the Menstkin reaction in the modification step (IV) described later to form a halogenated quaternary ammonium salt moiety. Therefore, a halogenated quaternary ammonium salt moiety can be easily formed by a one-step reaction without pretreatment with hydrochloric acid or the like after grafting. In addition, by using such a monomer, even when the simultaneous irradiation method is applied in the next graft polymerization step (II), the formation of homopolymer can be suppressed, and the graft polymerization to the substrate proceeds efficiently. Can be made.

  The monomer may contain a polymerization inhibitor in order to prevent spontaneous polymerization during storage or distribution. In a general polymerization method, there is a possibility that the intended polymerization may be stopped by such a polymerization inhibitor, and therefore a step of removing the polymerization inhibitor is essential. On the other hand, in the method for producing an anion exchange resin according to the present embodiment, since the graft polymerization is performed by irradiating with ionizing radiation in the graft polymerization step (II), the polymerization reaction proceeds even in the presence of a polymerization inhibitor. For this reason, the removal process of a polymerization inhibitor is not necessarily required.

  The solvent of the monomer solution containing a monomer having a halogenated hydrocarbon moiety is not particularly limited as long as the monomer is sufficiently dissolved. For example, a common solvent such as water, alcohol, acetone, ethyl acetate, A mixed solvent of two or more of the above-mentioned solvents can be used. Among them, it is preferable to use a mixed solvent of water and an organic solvent from the viewpoint that both the increase of the flash point by water and the high solubility in non-aqueous monomers by alcohol can be obtained and from the economical viewpoint.

  When the mixed solvent is used, the amount of the organic solvent in the monomer solution is not particularly limited, but the ratio of the volume of the organic solvent to the volume of the monomer solution (volume of organic solvent / volume of monomer solution) is 0. It is preferable that it is 2 or more. When the ratio of the volume of the organic solvent to the volume of the monomer solution is 0.2 or more, the solvent has a high flash point and high solubility. In addition, although it does not specifically limit as an organic solvent, It is preferable to use alcohol, and it is more preferable to use lower alcohols, such as methanol, ethanol, 1-propanol, 2-propanol, from a soluble viewpoint of a non-aqueous monomer. preferable.

  Here, in the dipping step (I), for example, by adjusting the conditions such as the addition amount of the monomer, the addition amount of the organic solvent, the addition amount of pure water, the graft ratio in the graft polymerization step (II) described later is set. Can be controlled. In order to achieve the graft ratio in the range as described above, the ratio of the amount of the monomer having a halogenated hydrocarbon moiety to the mass of the substrate (monomer having a halogenated hydrocarbon moiety / substrate) is as follows. 0.1 to 3 is preferable, and 0.5 to 2 is more preferable. In particular, an anion exchange resin having both a high graft rate, an anion recovery rate, and an anion saturated adsorption amount can be obtained by setting the amount of the monomer having a halogenated hydrocarbon moiety to the substrate to 0.5 to 2. The organic solvent to be added is preferably 2 to 20 times the amount of the monomer, and the pure water to be added is preferably 3 to 30 times the amount.

  The ratio of the mass of the monomer solution to the mass of the base material (monomer solution / base material) is not particularly limited and is, for example, preferably 1 or more and more preferably 2 or more. When the mass ratio of the monomer solution to the mass of the substrate is 1 or more, the substrate can be sufficiently immersed in the monomer solution. Moreover, as a ratio of the mass of the monomer solution with respect to the mass of the substrate, for example, it is preferably 30 or less, and preferably 20 or less. When the ratio of the mass of the monomer solution to the mass of the substrate is 30 or less, an anion exchange resin having a particularly high graft rate, anion recovery rate, and anion saturated adsorption amount can be obtained.

  In addition, the adsorption property of an anion may be improved by using a bulky material such as a hollow fiber, for example. In such a case, it is necessary to increase the amount of the monomer solution in order to allow the grafting reaction to proceed uniformly. As a result, the ratio of the mass of the monomer solution to the mass of the substrate may exceed 30. In such a case, the ratio of the mass of the monomer to the mass of the monomer solution (monomer / monomer solution) is preferably set to 1.0 or more, for example.

  The ratio of the mass of the monomer to the mass of the base material (monomer / base material) is not particularly limited and is, for example, preferably 0.5 or more, and more preferably 1 or more. When the ratio of the mass of the monomer to the mass of the substrate is 0.5 or more, the amount of chromium adsorbed at equilibrium can be improved by sufficiently graft polymerizing the graft chain on the substrate. Moreover, as a ratio of the mass of the monomer with respect to the mass of a base material, it is preferable that it is 5 or less, for example, and it is more preferable that it is 4 or less. When the ratio of the mass of the monomer to the mass of the substrate is 5 or less, the amount of monomer not exposed to the anion exchange resin surface can be suppressed, and the amount of monomer used can be reduced.

  In the immersion step (I), although it is not an essential aspect, it is preferable that an inert gas is blown into a monomer solution containing a monomer containing a halogenated hydrocarbon moiety to remove dissolved oxygen. Thereby, in the subsequent graft polymerization step (II), the polymerization termination reaction due to dissolved oxygen in the monomer solution can be suppressed, and the graft ratio can be improved.

  The atmosphere in the dipping step (I) is not particularly limited, but an inert gas atmosphere such as argon or nitrogen is preferable. Thereby, the amount of dissolved oxygen in the monomer solution at the time of the polymerization reaction in the graft polymerization step (II) can be reduced, the polymerization termination reaction due to the dissolved oxygen can be suppressed, and the graft ratio can be improved.

[Graft polymerization step (II)]
In the graft polymerization step (II), a base material immersed in a monomer solution containing a monomer having a halogenated hydrocarbon moiety is irradiated with ionizing radiation, and the monomer is graft-polymerized on the base material. This is a process for obtaining a graft-polymerized substrate.

  Here, as a base material, as a fiber, as it is, a yarn shape formed by twisting fibers, a bundle shape formed by bundling fibers or yarns twisted, and a cake shape constituted by yarns formed by twisting fibers or fibers In this graft polymerization step (II), a monomer solution is continuously supplied even between or inside the fibers by using a fiber cord or a thread cord made of twisted fibers. Thus, a graft polymer chain can be formed uniformly throughout the fiber.

  In addition, as described above, the irradiation of ionizing radiation in the graft polymerization step (II) is performed by immersing the substrate in a monomer solution containing a monomer having a halogenated hydrocarbon moiety, and then immersing the substrate in the monomer solution. (Hereinafter referred to as “simultaneous irradiation”). Specifically, the base material is immersed in a monomer solution containing a monomer having a halogenated hydrocarbon moiety in a predetermined container, and then, for example, the container is subjected to graft polymerization by irradiation with gamma rays.

  Here, when the monomer is graft-polymerized on the substrate, it is not simultaneous irradiation, but irradiation with ionizing radiation is performed before the substrate is immersed in the monomer solution, and radical active sites are generated on the substrate in advance ( Hereinafter, it is generally performed using “pre-irradiation”. This is also shown in Non-Patent Document 1, and when a substrate immersed in a monomer solution is irradiated with ionizing radiation, so-called simultaneous irradiation, only polymerization between monomers in the solution proceeds. Thus, it is considered that the homopolymer is produced and the grafting to the base material hardly proceeds.

  On the other hand, by using a monomer having an aromatic ring structure such as a halogenated hydrocarbon moiety, preferably a benzene ring, it is possible to suppress the formation of a homopolymer, and grafting to a substrate is effective by simultaneous irradiation. It progresses. Such simultaneous irradiation has an advantage that, for example, immersion of the base material in the monomer solution and irradiation of ionizing radiation can be performed in the same apparatus, and it can be manufactured by a simple method. .

  The atmosphere in the graft polymerization step (II) is not particularly limited, but is preferably an inert gas atmosphere such as argon or nitrogen. Thereby, the polymerization termination reaction due to dissolved oxygen in the monomer solution can be suppressed, and the graft ratio can be improved.

  The dose of ionizing radiation to be irradiated is not particularly limited, but is preferably 1 kGy or more, more preferably 5 kGy or more, further preferably 10 kGy or more, and particularly preferably 20 kGy or more. By irradiating the base material with ionizing radiation of 1 kGy or more, radical active sites that serve as starting points for graft polymerization can be sufficiently generated. On the other hand, the dose of ionizing radiation applied to the substrate is preferably 200 kGy or less, more preferably 100 kGy or less, further preferably 80 kGy or less, and particularly preferably 60 kGy or less. . When the dose of ionizing radiation applied to the substrate exceeds 200 kGy, the molecules constituting the substrate are cut, and the possibility of damage to the substrate increases. Moreover, when the dose of ionizing radiation to be irradiated is 20 kGy or more and 60 kGy or less, an anion exchange resin having both a high graft rate, an anion recovery rate, and an anion saturated adsorption amount can be obtained.

  Moreover, it does not specifically limit as ionizing radiation irradiated to a base material, An alpha ray, a beta ray, a gamma ray, an X ray, an electron beam, an ultraviolet-ray, etc. can be used. Among them, it is preferable to use a gamma ray or an electron beam because it is industrially easy to apply, and it is particularly preferable to use a gamma ray because it has a high permeability to a substance.

  The graft ratio of the anion exchange resin calculated by the above formula (1) in the graft polymerization step (II) is not particularly limited, but is preferably 10% or more, more preferably 30% or more. React. By setting the graft ratio of the anion exchange resin to 10% or more, the anion exchange resin can effectively adsorb the anion. By setting the graft ratio of the anion exchange resin to 30% or more, the amount of anion adsorbed can be increased. On the other hand, the reaction is performed so that the graft ratio is preferably 200% or less, more preferably 150% or less. When the graft ratio of the anion exchange resin exceeds 200%, the effect of improving the anion adsorption ability is small, and the strength of the resin may be lowered.

[Washing step (III)]
The washing step (III) is a homopolymer (by-product) as an impurity produced by a reaction between monomers by washing a graft polymerization base material into which a halogenated hydrocarbon has been introduced by graft polymerization with a Lewis basic organic solvent. Is a step of washing and removing.

  As described above, the use of a monomer containing a halogenated hydrocarbon moiety can suppress the formation of a homopolymer even if the simultaneous irradiation method is applied in the graft polymerization step (II). Polymers can form.

  Therefore, by washing the homopolymer as a by-product generated in the graft polymerization step (II), the homopolymer can be efficiently processed from the graft polymerization base material, and the resulting anion exchange resin is high. Has anion adsorption ability.

  Examples of the cleaning solvent include hydrocarbon solvents (hexane, toluene, etc.), alcohol solvents (methanol, ethanol, propanol, butanol, etc.), Lewis basic organic solvents, aqueous sodium hydroxide, and the like. Among these, it is preferable to use a Lewis basic organic solvent or a sodium hydroxide aqueous solution from the viewpoint of the influence on the environmental load and the ability to clean the homopolymer.

  Examples of the Lewis basic organic solvent include, but are not limited to, for example, 2-methoxy-1-methylethyl acetate, esters (methyl acetate, ethyl acetate, n-butyl acetate, n-propyl acetate, isobutyl acetate, isopropyl acetate ), Ketones (acetone, methyl ethyl ketone, methyl propyl ketone, diethyl ketone, methyl-n-butyl ketone, methyl butyl isobutyl ketone, methyl amyl ketone, methyl isoamyl ketone), ethers (diethyl ether, isopropyl ether, ethyl propyl ether, n -Butyl ether, dioxane), methylaniline, dimethylaniline, pyridine, butyronitrile, N, N-dimethylformamide, aniline, N, N-dimethylaniline, ethanolamine, dipropylamine, propylamido , Diethylamine, cyclohexylamine, ethylenediamine, n-butylamine, t-butylamine, triethyleneamine, acetonitrile, propionitrile, vityronitrile, capronitrile, benzonitrilepropionitrile, dimethylsulfoxide, N-methyl-2-pyrrolidone, dimethylacetamide, Diethylacetamide, diethylformamide and the like can be used. Among them, it is preferable to use 2-methoxy-1-methylethyl acetate from the viewpoint of high detergency and load on the environment and human body.

  In the case of washing with a Lewis basic organic solvent, it is preferably further washed with a water-soluble organic solvent such as alcohols or acetone to make it hydrophilic. When the Lewis basic organic solvent is washed with a water-insoluble Lewis basic organic solvent and this Lewis basic organic solvent remains on the graft polymerization substrate, the modification reaction of the tertiary amine in the modification step (IV) described later is inhibited. Therefore, the modification reaction of the tertiary amine in the modification step (IV) can proceed smoothly by hydrophilizing the surface and inside of the graft polymerization base material using a water-soluble organic solvent such as alcohols or acetone. it can. For this reason, it is preferable to wash the graft polymerization substrate with a Lewis basic organic solvent and then immediately with a water-soluble organic solvent, not with water.

  The alcohol is not particularly limited as long as it is a solvent having a hydroxyl group, and specifically, methanol, ethanol, 1-propanol, 2-propanol and the like can be used. Of these, 2-propanol is preferably used from the viewpoint of easy handling based on the high boiling point, homopolymer removal ability, and the like.

  The concentration of the aqueous sodium hydroxide solution is not particularly limited. For example, it is preferably 0.1 mol / L or more, more preferably 0.5 mol / L or more, and 1.0 mol / L. More preferably, it is the above. When the concentration of the sodium hydroxide aqueous solution is 0.1 mol / L or more, it has particularly high detergency. Moreover, as a density | concentration of sodium hydroxide aqueous solution, it is preferable that it is 10 mol / L or less, It is more preferable that it is 8 mol / L or less, It is further more preferable that it is 5 mol / L or less. When the concentration of the aqueous sodium hydroxide solution is 10 mol / L or less, the strength can be maintained without deterioration of the base material.

  The specific means for washing is not particularly limited, and a washing machine or a cheese dyeing machine can be used. Further, an ultrasonic cleaning machine can be used.

  As the washing machine, either a household machine or an industrial machine can be used. In addition, as a washing machine, the washing tub is rotated to the side or at an angle, and the fiber that has absorbed the Lewis basic organic solvent falls from the top to the bottom. It is possible to use a vertical washing machine or the like in which Lewis basic organic solvent is stored and the fibers are immersed, and the rotating blades at the bottom of the washing tub are rotated to stir the fibers by stirring and running water.

  A cheese dyeing machine is generally used for dyeing fibers or yarns wound around bobbins, but is used for washing fibers or yarns wound around bobbins. Thus, a graft polymerization base material can be washed at low cost by using a cheese dyeing machine.

  For example, in the case of using fibrous nylon as a base material, if the fineness exceeds about 800 dtex, it becomes bulky, and a 10 L container is required to wash 1 kg of nylon with a fineness of 1000 dtex. When used, for example, as compared with ultrasonic cleaning or the like, mass production is possible while lowering costs without requiring expensive explosion-proof equipment.

[Modification step (IV)]
In the modification step (IV), a tertiary amine is reacted with a graft polymerization base material into which a halogenated hydrocarbon has been introduced by graft polymerization to form a halogenated quaternary ammonium salt. This is a step of imparting anion exchange ability.

  The reaction of forming a halogenated quaternary ammonium salt with the above-mentioned halogenated hydrocarbon and a tertiary amine is referred to as the Menstkin reaction. The halogenated quaternary ammonium salt produced by this reaction has an anion exchange ability.

  As the reaction conditions for the addition reaction to the graft chain of the tertiary amine in the modification step (IV), general conditions for the Menstkin reaction can be employed.

  The tertiary amine is not particularly limited as long as it is a compound containing a tertiary amino group. Specifically, trimethylamine, N, N′-dimethylethylamine, N, N′-dimethylisopropylamine, N, N, N ′, N′-tetramethyldiaminomethane, tris (dimethylamino) methane, N, N′-diethylmethylamine, N, N′-tetramethylethylenediamine, N, N′-dimethylethylenediamine, N, N, N ′ , N ″, N ″ -pentamethyldiethylenetriamine, triethylamine, N, N, N ′, N′-tetramethyl-1,3-diaminopropane, N, N, N′-trimethylethylenediamine, tris [2- ( Dimethylamino) ethyl] amine, N-butyldimethylamine, N, N′-diisopropylethylamine, triethyl Diamine, N, can be used N'- dimethylpiperazine, and the like. Among these, triethylenediamine is preferable because it has high anion exchange ability.

  EXAMPLES Hereinafter, although the Example of this invention is shown and demonstrated in detail, this invention is not limited to these Examples at all.

[Example 1]
(Sample preparation)
As a base material that is a polymer material, nylon 6 fiber (940T-68-255 manufactured by Toray Industries Inc.) is wound in units of 200 g per bundle, and 5 bundles (1 kg in total) are weighed into a 14 L cylindrical container with a diameter of 210 mm. It was.

  Next, a monomer solution composed of 1.5 L of 4- (chloromethyl) styrene (AGC Seimi Chemical Co., Ltd. CMS-14), 4.25 L of 2-propanol, and 4.25 L of pure water was placed in a cylindrical container. The material was immersed in the monomer solution. The inside of the container was sealed with nitrogen gas after removing oxygen.

Then, the gamma ray was irradiated with the dose of 40 kGy with the container by the gamma ray irradiation apparatus which has ⁶⁰ Co as a radiation source.

  Samples obtained after gamma irradiation were sampled from a total of 15 points divided into 5 equal parts in the radial direction of the reaction vessel and 3 equal parts in the vertical direction, and ultrasonication was performed using 2-methoxy-1-methylethyl acetate. The sample was washed with a wash. The washed substrate was hydrophilized with 2-propanol and further washed with water. The obtained graft polymerization sample was put in a water bath and reacted at 85 ° C. for 3 hours in a 5 mass% aqueous solution of triethylenediamine (TEDA). Thereafter, it was washed and dried at room temperature to obtain an anion exchange resin sample.

(Measurement of equilibrium chromium adsorption)
In order to confirm the anion exchange ability of the obtained anion exchange resin, after the anion exchange resin was immersed in a chromium solution, the amount of chromium adsorbed on the anion exchange resin after reaching equilibrium was calculated.

Specifically, 50 mg of the obtained anion exchange resin (chromium adsorption resin) and a potassium dichromate aqueous solution with a Cr ⁶⁺ concentration of 100 mg / l adjusted to pH 8.0 were placed in a 100 ml beaker at room temperature for 24 hours. After stirring, the adsorption resin and the Cr ⁶⁺ filtrate were separated by filtration. For recovered filtrate inductively coupled plasma emission spectroscopy performed (ICP-AES analysis) measures the ^{Cr 6+} concentration, based on the equation (2) below was calculated ^{Cr 6+} adsorption amount when ^{Cr 6+} adsorption equilibrium.

Equilibrium chromium adsorption [mg / g-adsorbent]
= (Cr ^{6 +} initial concentration [mg / l] -Cr ^{6 +} concentration after adsorption [mg / l]) × capacitance of potassium dichromate aqueous solution [l] / ion exchange resin mass [g] (2)

  There was a variation in the equilibrium chromium adsorption amount of the collected samples, and the ratio of the minimum value to the maximum value of the equilibrium chromium adsorption amount among these was 0.8. The maximum value was obtained from the sample collected from the outside of the container, and the minimum value was obtained from the sample collected from the inside of the container. It is considered that the graft polymerization proceeded further on the outside where the gamma ray irradiation amount was larger.

[Example 2]
A sample was prepared in the same manner as in Example 1 except that 1 kg of nylon 6 fiber (940T-68-255 manufactured by Toray Industries Inc.) was used as a base material in a 60 cm × 60 cm laundry net in the form of a fiber.

  There was a variation in the equilibrium chromium adsorption amount of the collected samples, and the ratio of the minimum value to the maximum value of the equilibrium chromium adsorption amount among these was 0.8.

Example 3
A sample was prepared in the same manner as in Example 1 except that nylon 6 fiber (940T-68-255 manufactured by Toray Industries, Inc.) was braided as a base material, processed into a molding cord, and 1 kg was cut out and used.

  There was a variation in the equilibrium chromium adsorption amount of the collected samples, and among these, the ratio of the minimum value to the maximum value of the equilibrium chromium adsorption amount was 0.6.

[Comparative Example 1]
Except that 1 kg of nylon 6 fiber (940T-68-255 manufactured by Toray Industries, Inc.) was wound around a bobbin as a substrate and processed into a cheese shape having a winding density of 0.2, all operations were performed in the same manner as in Example 1.

  The amount of adsorption of the equilibrium chromium of the collected samples varied, and the ratio of the minimum value to the maximum value of the adsorption amount of equilibrium chromium among these was 0.2.

  Table 1 shows the shapes formed by the fibers as the base materials of Examples 1 to 3 and Comparative Example 1, the tension applied to the fibers in the base materials, and the minimum / maximum values of the equilibrium chromium adsorption amount.

  From Table 1, in Example 1 using casserole-wound fibers in which the fibers are not dense and Example 2 using unraveled fibers, the minimum / maximum value of the equilibrium chromium adsorption amount in a plurality of samples taken from the same lot Was 0.8, and in Example 3 using a Mole cord-like fiber, the minimum / maximum value of the equilibrium chromium adsorption amount was 0.6, and the difference within the same lot was small. On the other hand, in Comparative Example 1 using cheese-like fibers, the minimum / maximum value of the equilibrium chromium adsorption amount was 0.2, and the difference was large even in the same lot as compared with Examples 1 to 3.

  In Comparative Example 1, it is considered that the graft polymerization of the fiber did not proceed sufficiently inside the cheese, and thus was not modified with the tertiary amine, and the difference in the equilibrium chromium adsorption amount was large within the same lot. More specifically, in the case where the fiber is tensioned and wound like a cheese-like fiber, the fibers are in close contact with each other, the monomer solution is hardly supplied between the fibers, and the fibers are in close contact with each other. Even if radicals are generated in the part, it is considered that the graft polymerization did not proceed only in that part because the monomer is difficult to be supplied.

  In addition, Example 1 using casket winding and Example 2 using fibers as they were had less difference in the amount of equilibrium chromium adsorbed in the same lot than Example 3 using mole cord-like fibers. This is because there is no portion where the fibers are densely packed in the case of a casket-wrapped fiber or a fiber as it is, but in the case of a mall cord fiber, the vicinity of the core material is knitted and inflexible, and the fibers are closely packed together. It is considered that graft polymerization did not proceed only in that portion.

  From the above, it was found that higher anion exchange ability can be obtained by using a base material having a shape in which no tension is applied to the fibers and the fibers are not densely packed.

Claims (1)

An immersion step of immersing the fibrous base material in a monomer solution containing a monomer having a halogenated hydrocarbon moiety;
A graft polymerization step of irradiating the base material immersed in the monomer solution with ionizing radiation, graft polymerization of the monomer onto the base material, and obtaining a graft polymerization base material;
A modification step of modifying a tertiary amine on the graft polymerization substrate,
The base material is in the form of a fiber, a yarn formed by twisting fibers, a bundle formed by bundling fibers or yarns twisted, a cake formed of fibers or yarns formed by twisting fibers, and A method for producing an anion exchange resin, wherein the anion exchange resin is in one or more states selected from the group consisting of a fiber cord or a mall cord formed of yarns formed by twisting fibers.

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