JPH0713093B2 - Cation exchange resin and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to a latex-type (pericular type) cation-exchange resin in which an ion-exchange latex is chemically held on the surface of a substrate, and a method for producing the same. More specifically, the present invention relates to a cation exchange resin that prevents desorption of an ion exchange latex from a substrate and a method for producing the same.

<Prior art> Ion exchange resins used in high-performance liquid chromatographs (for example, ion chromatographs) have a much smaller ion exchange capacity than general ion exchange resins (1/10 of general ion exchange resins). ~ 1/500) is made.
The method for producing such an ion exchange resin having a low ion exchange capacity is a special production method, which is largely different from general ion exchange resins, and the production method is roughly classified into two. That is, in the first production method, a resin having a low ion exchange capacity is prepared by holding a very small amount of ion exchange latex on the surface of a resin as a base material (the resin itself is often a packing material for chromatography). This is a so-called latex type ion exchange resin production method, and the second production method is a so-called chemical bond type in which an ion exchange group is chemically introduced directly into the surface functional group of the base resin to produce a low ion exchange capacity resin. Of the ion exchange resin. On the other hand, an ion chromatograph,
Especially in the suppressed ion chromatograph, the latex ion exchange resin is most often used,
Chemically bonded ion exchange resins are mainly used in non-suppressed ion chromatographs, and are almost not commercially available for suppressed ion chromatographs. Also,
Latex-type ion-exchange resin is based on polystyrene gel or ammonified polystyrene gel as a base material, and has a particle size of 0.
It is one in which a cation exchange latex of about 01 to 0.1 μm is held. This type of ion exchange resin
Since the ion-exchange groups are present only in high density on the surface of the resin, the separation equilibrium is very fast and has a high resolution.

However, since the latex-type ion-exchange resin is not a filler in which the latex having an ion-exchange group and the base material are strictly integrated, desorption of the ion-exchange latex occurs depending on the use conditions, and there is a possibility that the separability is reduced. It has the drawback of being expensive. That is, for example, in the electrostatic adsorption type, there is a risk of desorption due to a sudden change in the ionic strength of the mobile phase or sample,
In the physical adsorption type, there is a risk of desorption due to the mixing of organic solvent or mechanical load.

<Problems to be Solved by the Invention> However, the chemical bond type filler (ion exchange resin) has various characteristics which the latex type filler (ion exchange resin) does not have, and the latex type filler also has excellent performance. Although they are comparable to each other, they do not necessarily replace the latex type fillers in terms of separation performance and separation characteristics. For example, regarding the stability of the ion-exchange group, the ion-exchange resin having polystyrene as a matrix and used as a general latex-type filler is superior to the hydrophilic chemical-bonding type filler. Also, any latex type filler can be used as long as it does not adversely affect the separation, so it is easy to improve it to a hard and high pressure resistant filler for speeding up, but it is a chemical bond type filler. In the case of agents, it is generally difficult to improve them to hard and high pressure resistant fillers without significantly changing the separation characteristics. Since latex type fillers have such advantages, it is expected that latex type fillers will continue to be the mainstream in the future, but for that reason it is necessary to make fillers that do not desorb latex, The cation exchange resin and its manufacturing method have been strongly demanded.

The present invention has been made in view of such circumstances, and an object thereof is to provide a latex type cation exchange resin suitable for use in an ion chromatograph or the like without desorption of the ion exchange latex and a method for producing the same. Is intended.

<Specific Means for Solving Problems> In order to achieve such an object, the present invention is a cross-linkable polymer gel having an ammonium group on the surface thereof, a halogen group, a hydroxyl group, or an epoxy group. A base material made of a resin having a cation exchange latex that is electrostatically adsorbed with an ammonium group of the base material, and reacts with a halogen group, a hydroxyl group, or an epoxy group of the base material to form a chemical bond, A latex-immobilized polymer layer which covers the base material and electrostatically adsorbed cation-exchange latex and holds the base material on the base material, so that the ion-exchange latex is not desorbed from the base material. A cation exchange resin characterized in that

Further, in the method for producing a cation exchange resin, a step of dispersing a crosslinkable polymer gel having an ammonium group on the surface and having a halogen group, a hydroxyl group, or an epoxy group in an organic solvent, and a cation exchange latex in an organic solvent. A step of dispersing, a step of gradually adding and stirring the suspension of the cation exchange latex to the slurry of the crosslinkable polymer gel, and then mixing a polyfunctional epoxy compound to be a fixed polymer layer in the slurry, It is characterized in that it is prepared from a step of adding a reaction initiator to this mixture and reacting it at a constant temperature for a predetermined time, and a step of washing the reaction product and then exchanging it with a target counterion.

<Example> Hereinafter, the present invention will be described in detail with reference to the drawings. First
The drawings are process explanatory views for explaining the method for producing a cation exchange resin according to the present invention. In this figure, first, a polymer gel having an ammonium group and having a hydroxyl group, a halogen group, or an epoxy group is prepared in accordance with the reaction method (in the case of a resin having no ammonium group, it is ammoniumized in advance). Next, the polymer gel (resin) is dispersed in a small amount of organic solvent. Then, the ion exchange latex is dispersed in an organic solvent. Next, the suspension of the ion-exchange latex is gradually added to the polymer gel (resin) slurry and stirred. After that, a polyfunctional epoxy compound to be a fixed polymer layer is mixed with the slurry. Finally, a reaction initiation catalyst is added, and the reaction is carried out at a constant temperature for a constant time. The resin thus obtained is washed with an organic solvent, then thoroughly washed with water, and then exchanged with a desired counterion. The ion exchange resin thus obtained is packed in an appropriate chromatographic tube and used as a separation column or the like for ion exchange chromatography or the like.

The above-described manufacturing method will be described in more detail with reference to the following. First, 2.5 g (dry weight) of a hydroxyalkylmethacrylate-based crosslinked polymer gel (particle size: 12 μm) is dispersed in 20 ml of 1N sodium hydroxide. Add 2 g of epichlorohydrin to this gel slurry,
While stirring, the reaction is carried out in a constant temperature bath at 40 ° C for 2 hours to introduce an epoxy group. 450 μmol / g of epoxy groups were introduced into this epoxidized resin. The epoxidized resin is dispersed in a 30% aqueous solution of trimethylamine and stirred for 3 hours in a constant temperature bath at 4 ° C. for ammonium conversion. The ion exchange capacity of this resin is about 300 μeq / g. This resin is used as a base resin.

The above base resin (dry weight: about 2.5 g) is dispersed in 10 ml of 1,4-dioxane and stirred with a stirrer. Cation exchange latex (ion exchange capacity of 3.5 m
eq / g) methanol suspension (latex concentration 2%) 10 ml
Add. Then, 1.5 g of diglycerin polyglycidyl ether to be the latex-fixed polymer layer was added, and the mixture was reacted for 5 hours in a shaker at 45 ° C. using boron trifluoride diethyl ether complex as a catalyst. Dioxane after reaction
After washing with 50 ml, it was washed with 100 ml of methanol and then 100 ml of pure water. Then, it was dispersed in 0.5 N sulfuric acid, ultrasonic waves were applied for 15 minutes, and then filtered. Furthermore, 0.5N sulfuric acid
After washing with 50 ml, wash with pure water until the filtrate becomes neutral, disperse in 100 ml of pure water, and centrifuge to 1,000
Decantation was performed 6 times at a rotation speed of rpm. afterwards
It was dispersed in 1.0 N sodium chloride and left overnight. The cation exchange resin thus obtained had an ion exchange capacity of 35 μEq / g.

By the way, the structure of the ion exchange resin (filler) manufactured as described above is as shown in FIG. In FIG. 2, 1 is a base material made of, for example, an anion exchange resin, 2
Is a cation exchange latex composed of, for example, a cation exchange group or a cation exchange resin itself, and 3 is a latex-immobilized polymer layer formed by bonding the base material 1 and the cation exchange latex 2 with, for example, an ether bond. As shown in FIG. 2, the ion exchange resin produced by the production method of the present invention is
The base material 1, the ion-exchange latex 2, and the latex-fixed polymer layer 3 are composed of three parts. The latex-fixed polymer layer 3 is a resin (base material) 1 on which the cation-exchange latex 2 is held.
It is designed to cover. Further, the base material 1 is required to be a crosslinkable polymer gel or to have the following functional groups on its surface or to be able to introduce the functional groups.
That is, it is necessary that the resin has a halogen group, a hydroxyl group, or an epoxy group, and examples thereof include ammonium polyhydroxyalkyl methacrylate, ammonium polyvinyl alcohol, ammonium polyglycidyl methacrylate, ammonium polyglycidyl ether, and ammonium. It must be a resin such as polychloromethylstyrene. Further, it is possible to directly ammonate or ammonified after epoxidation, and after the ammonification, an epoxy group, a resin having a halogen group or a hydroxyl group (for example, polyhydroxyalkyl methacrylate, polyvinyl alcohol, polyglycidyl methacrylate, halogenated polyhydroxyalkyl methacrylate, Polymethylol styrene, polychloromethyl styrene, an epoxy group, a primary hydroxyl group, a polyether having a halogen group, or the like) can also be used as a base. Further, the ion exchange latex 2 has a particle size of 0.01
It is a strong cation-exchange resin of 0.1 μm. The matrix of the ion-exchange latex 2 may be polystyrene-based or polymethacrylate-based, but the polystyrene-based is preferred when an ion-exchange resin having good alkali resistance is required. The shape of the cation exchange latex 2 is not necessarily spherical and may be a crushed type. On the other hand, the latex-immobilized polymer layer 3 is composed of a monomer capable of reacting with a hydroxyl group, a halogen group or an epoxy group of the base material 1 and coating the surface of the base material 1 while crosslinking the surface of the base material 1. As an actual substance, when the residual functional group in the base material 1 is a hydroxyl group or an epoxy group, a polyfunctional epoxy compound such as glycerin polysidyl ether is preferable. Also,
An oligomer of an epoxy compound may be used as long as it is a substance relatively having a residual epoxy group. Further, when the residual functional group in the base material 1 is a halogen group, a compound (for example, a polyol compound) and a polyfunctional epoxy which react with the halogen group and also with the polyfunctional epoxy compound as described above. The compound may be mixed and reacted to form a polymer layer.

On the other hand, the latex-immobilized polymer layer 3 is obtained by polymerizing the monomer added during the above-mentioned production. Since this monomer also reacts with the surface functional groups (hydroxyl group / halogen group / epoxy group) in the substrate, The latex-fixed polymer layer 3 formed by the reaction is also chemically bonded and fixed to the base material 1. Since this monomer is a polyfunctional monomer, the latex-immobilized polymer layer formed by polymerization is a crosslinkable polymer layer. Therefore, the polymer layer 3 does not peel off from the base material 1. The cation exchange latex 2 is fixed to the base material (resin) 1 by the electrostatic adsorption force and the coating of the latex fixing polymer layer 3, but the monomer for forming the latex fixing polymer layer 3 is cation exchange. Since it penetrates into the fine pores of the latex and polymerizes, it is more firmly fixed than a simple coating. Since the ion exchange resin of the present invention holds the cation exchange latex 2 with the above-mentioned structure, the cation exchange latex is not desorbed by the organic solvent or the high ion concentration solution. Further, since the base material 1, the cation exchange latex 2 and the latex fixed polymer layer 3 are integrated by chemical bonding, the cation exchange latex 2 is hardly desorbed even by a mechanical load. Furthermore, the latex-immobilized polymer layer 3 is a three-dimensional crosslinkable polymer, and since the base material 1 is covered with a strong shell, the base material 1
There is also a secondary effect that the degree of swelling / shrinkage is reduced and the pressure resistance is improved.

The cation exchange resin produced as
It was packed in a stainless steel column having a length of 4.6 mm and a length of 100 mm, and subjected to ion chromatography with an acidic mobile phase. The analysis conditions at this time were that the mobile phase was 5 mM HNO ₃ 2.0 ml / min, the measurement temperature was 45 ° C., the detector was a conductivity detector, and the sample concentration was Li ⁺ 2 ppm, Na ⁺ 10 ppm, NH ₄ ⁺ 20ppm, K ⁺ 20ppm, sample injection amount is 50μ. The chromatograph obtained under such analysis conditions, the measured components contained in the injected sample are separated in a good peak shape in a short time,
With the cation exchange resin obtained by the production method of the present invention, ion chromatography can be sufficiently performed.
In addition, the filling flow rate when the substrate itself (resin before reaction) used in the above-mentioned example was packed in a column having the same column size as this example (inner diameter 4.6 mm, length 100 mm)
Although it was 3.8 ml / min, the resin after the reaction could be filled at 4.5 ml / min. This means that the flow resistance (pressure resistance) of the substrate was improved by using the manufacturing method of the present invention. Although this is not the purpose of the present invention, it can be said that it is a secondary effect obtained by the present invention.

Further, in order to investigate the stability of the present invention and the resin against desorption of the cation exchange latex, the packing material was extracted from the column of the above-mentioned example and dispersed in various solutions, and tested. That is, first, in order to examine the stability against an organic solvent, the extracted resin was dispersed in isopropyl alcohol and immersed in a constant temperature bath at 50 ° C. for 8 hours. afterwards,
The resin was washed with pure water, packed in the same stainless steel column as in the above-mentioned example, and subjected to ion chromatography. As a result, there was no change in the retention time of each ion. This indicates that desorption of the cation exchange latex did not occur in the organic solvent. Next, the same resin was dispersed in 1M sodium chloride and 1N hydrochloric acid, and the same test was conducted.In both cases, however, shortening of the retention time was not observed, and the cation exchange latex was stable and the base resin Found to be held. From such experimental results, it is understood that the resin of the present invention is more stable than the simple electrostatic adsorption type. In addition, although the stability of conventional latex type fillers has been actually investigated, the retention time of the fillers held by the binder is about 1/3 when dispersed in 50% isopropyl alcohol. Decrease. Also, shortening of the holding time is observed even by stirring with a stirrer or shaking for a long time. There is not much knowledge about the electrostatic adsorption type, but when treated with a solution with high ionic strength,
A reduction in retention time is observed, though not as much as when the sizing mold is treated with an organic solvent. It is also said that the stability in organic solvents is not so good.

<Effects of the Invention> As described in detail above, according to the cation exchange resin described in the first aspect of the present invention, the base material and the latex-immobilized polymer layer are chemically bonded to form a base material. Since the electrostatically adsorbed cation-exchange latex is coated with the latex-fixed polymer layer, there is no desorption of the ion-exchange latex from the substrate, and the separation ability by desorption of the ion-exchange latex is improved. There is no decline.

In addition, since the latex-immobilized polymer layer is a three-dimensional crosslinkable polymer that covers the base material with a strong shell, the degree of swelling and shrinkage of the base material is reduced, and the pressure resistance is improved. There is also.

According to the method for producing a cation exchange resin described in the second invention, a suspension of a cation exchange latex is gradually added to a slurry of a crosslinkable polymer gel and stirred, and then this slurry becomes a fixed polymer. Since the polyfunctional epoxy compound is mixed, when the cation exchange latex is located around the substrate, the cation exchange latex is provided on the surface side in order to react the latex fixing polymer layer with the substrate. It is possible to obtain a cation exchange resin having good exchange ability.

[Brief description of drawings]

FIG. 1 is an explanatory view of a manufacturing method according to an embodiment of the present invention.
The figure is a schematic view of a cation exchange resin produced according to the method of the present invention. 1 ... Substrate, 2 ... Cation exchange latex, 3 ... Latex fixed polymer layer

Claims (2)

[Claims] 1. A base material, which is a crosslinkable polymer gel and has a resin having an ammonium group, a halogen group, a hydroxyl group, or an epoxy group on its surface, and an electrostatic adsorption with the ammonium group of the base material. And a cation-exchange latex which reacts with a halogen group, a hydroxyl group, or an epoxy group of the base material to chemically bond with the base material, and the base material is coated with the cation-exchange latex electrostatically adsorbed to the base material. A cation exchange resin, comprising: a latex-fixing polymer layer retained on the substrate, and the ion exchange latex not to be desorbed from the substrate. 2. A method for producing a cation exchange resin, the step of dispersing a crosslinkable polymer gel having an ammonium group and a halogen group, a hydroxyl group, or an epoxy group on the surface in an organic solvent, and the cation exchange latex being an organic solvent. A step of dispersing in a solvent, and a suspension of the cation exchange latex is gradually added to the slurry of the crosslinkable polymer gel and stirred, and then a polyfunctional epoxy compound to be a fixed polymer layer is mixed with this slurry. A step of adding a reaction initiator to this mixture, reacting it at a constant temperature for a certain time, and washing this reaction product, and then exchanging it with a target counterion. Resin manufacturing method.