JP3485234B2 - Anion exchanger, method for producing the same, and chemical filter - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an anion exchanger,
Regarding the manufacturing method and the chemical filter, more specifically, for example, an anion exchanger used in an acidic atmosphere as a woven / nonwoven fabric, a hollow fiber, a film or a processed product thereof, a manufacturing method thereof and a chemical filter using the same. Regarding

[0002]

2. Description of the Related Art A woven or non-woven fabric, a hollow fiber, a film or the like may be manufactured with an ion exchanger to form a chemical filter. The ion exchanger used for such a purpose is usually formed by graft polymerizing an ion exchange group on a polymer base material. To graft-polymerize an ion-exchange group, for example, a method in which a monomer having an ion-exchange group is directly polymerized, or a monomer having a functional group capable of being converted into an ion-exchange group is graft-polymerized, and then it is converted into an ionic group Method. For the graft polymerization, a method such as radiation irradiation is adopted. As the graft group to be polymerized on the polymer substrate, for example, a strongly acidic cation exchange group such as a sulfone group,
Weakly acidic cation exchange groups such as carboxyl groups, strong basic anion exchange groups such as quaternary ammonium groups, weak basic anion exchange groups composed of primary amino groups, secondary amino groups or tertiary amino groups are often used. Are known.

Among these, examples of the monomer having a weakly acidic cation exchange group include acrylic acid, methacrylic acid, maleic acid, fumaric acid and itaconic acid. Acrylic aminoalkyl esters such as dimethylaminoethyl acrylate (abbreviation: DMAEA), diethylaminoethyl acrylate (abbreviation: DEAEA), dimethylaminoethyl methacrylate (hereinafter also referred to as DMAEMA) are used as the monomer having a weakly basic anion exchange group. , Diethylaminomethyl methacrylate (hereinafter referred to as DEAEMA
(Also referred to as)) and other ester-based monomers such as aminoalkyl methacrylates. These are liquids and react well with the polyolefin-based polymer base material such as polyethylene and polypropylene suitable for the radiation graft polymerization method as they are.

However, weakly acidic cation exchange groups and weakly basic anion exchange groups have weak ion exchange action. It is necessary for the ion exchanger used in an acidic atmosphere to be graft-polymerized with a strongly basic anion exchange group and for the ion exchanger used in a basic atmosphere to be graft-polymerized with a strongly acidic cation exchange group. is there. A monomer having a strongly acidic cation exchange group and a monomer having a strongly basic anion exchange group are sold as salts such as sodium salt and chloride in consideration of stability. As examples of the former, sodium styrenesulfonate, sodium allylsulfonate, sodium methacrylsulfonate, etc. are known, and as examples of the latter, vinylbenzyltrimethylammonium chloride (hereinafter also referred to as VBTAC), 2-hydroxy-3- Methacryloxypropyl ammonium chloride, dimethylaminoethyl methacrylate-methyl chloride salt and the like are known.

Since a monomer having a strongly acidic cation exchange group and a monomer having a strongly basic anion exchange group are water-soluble, they are hard to adapt to hydrophobic materials such as polyolefins as a polymer base material and extremely difficult to graft. . Therefore, conventionally, when producing an ion exchanger in which a strongly acidic cation exchange group is graft-polymerized, sulfonation is carried out after grafting a monomer capable of introducing a sulfone group, for example, styrene, glycidyl methacrylate, glycidyl acrylate, etc. Was there. When producing an ion exchanger having a strongly basic anion exchange group as a graft group,
A monomer capable of introducing a quaternary ammonium group, for example, chloromethylstyrene was graft-polymerized, and then quaternary ammonium was converted using a chemical such as trimethylamine.

The synthesis of the ion exchanger is usually carried out in two steps such as the graft polymerization step and the functional group introduction step. If the ion exchanger is synthesized in two steps, the manufacturing process becomes complicated by itself. In the sulfonation reaction, concentrated sulfuric acid or chlorosulfuric acid is reacted for a long time. These cause problems such as damage and deterioration of equipment and generation of low molecular eluate. To introduce the quaternary ammonium group, chloromethyl methyl ether, which has a carcinogenic effect, or trimethylamine, which is a legal malodorous substance, must be used. Such a reaction process causes problems that the working environment is deteriorated and the load on the global environment is increased.

As a method for solving such a problem,
Japanese Unexamined Patent Publication No. 6-49236 proposes to graft-polymerize a mixed monomer system of a hydrophilic monomer and a monomer having an ion exchange group onto a polymer base material. In this proposal, in addition to anionic monomers such as hydroxyethyl methacrylate, vinylpyrrolidone, and dimethylacrylamide as hydrophilic monomers, monomers having a cation exchange group such as acrylic acid and methacrylic acid and anions such as diethylaminoethyl methacrylate. Monomers having exchange groups are mentioned.

[0008]

However, when the present inventors actually attempted to produce an anion exchanger based on this proposal, they found that there were some problems. That is, using a mixed monomer of vinylbenzyltrimethylammonium chloride (VBTAC), which is a monomer having a strongly basic ion-exchange group as its chloride, and diethylaminomethylmethacrylate (DEAEMA), which is a hydrophilic monomer, a nonwoven fabric made of polyethylene fibers is formed. An attempt was made to produce anion exchange fibers by carrying out graft polymerization.

At this time, the following problems were recognized. (1) If you try to adjust to a sufficient monomer concentration, VBT
Separation of the AC aqueous solution and the DEAEMA solution occurred, and uniform graft polymerization could not be performed. (2) The amount of DEAEMA grafted is large and the VBTAC graft ratio is not sufficient. Therefore, the amount of quaternary ammonium group introduced is small. (3) When the quaternary ammonium group (salt type) is regenerated with an alkali, the ester of DEAEMA partially hydrolyzes,
The amount of weakly basic anion exchange decreased. (4) The water content was small, and the removal performance for acid gas in the air was not sufficient.

Unless these problems are solved, sufficient ion exchange performance cannot be exhibited, and the effect of removing acidic gas as a chemical filter is not sufficient. Therefore, the present invention has a simple process, does not use a chemical that may cause deterioration of the working environment and the global environment, has sufficient ion exchange performance, and is excellent in the effect of removing an acidic substance to be removed. Another object of the present invention is to provide a method for producing such an anion exchanger and to provide such a chemical filter.

[0011]

That is, the object of the present invention is achieved by the following constitutions. (1) Irradiating an organic polymer base material with radiation to obtain a mixture of an amide-based monomer having a primary amino group, a secondary amino group or a tertiary amino group and a monomer having a quaternary ammonium group. An anion exchanger characterized by being graft-polymerized to a material. (2) The organic polymer base material is irradiated with radiation to obtain a mixture of an amide-based monomer having a primary amino group, a secondary amino group or a tertiary amino group and a monomer having a quaternary ammonium group. A method for producing an anion exchanger, which comprises graft-polymerizing a material. (3) The method for producing an anion exchanger according to (1) above, wherein the monomer having a quaternary ammonium group is vinylbenzyltriorganoammonium halide.

(4) Production of the anion exchanger according to (1) or (2) above, wherein the organic polymer base material is selected from fibers, woven or nonwoven fabrics which are fiber aggregates, and processed products thereof. Method. (5) A chemical filter containing the anion exchanger according to (1 ) above .

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The embodiment of the present invention will be described below, but the present invention is not limited to this embodiment. The anion exchanger is formed by irradiating an organic polymer compound as a base material with radiation and graft-polymerizing a predetermined monomer on the organic polymer base material. Examples of the base material to be graft-polymerized include polyolefin polymers such as polyethylene and polypropylene, and halogenated polyolefin such as vinyl chloride. Among them, polyethylene is particularly preferable. A polymer obtained by graft-polymerizing an ion exchange group is generally difficult to mold. Therefore, at the stage of the base material before the graft polymerization, for example, a fiber, a woven fabric or a non-woven fabric which is a fiber aggregate, or a molded product formed into a processed product thereof may be selected. These can be easily processed into chemical filters. In particular, woven and non-woven fabrics are suitable as materials for chemical filters because they are lightweight and easy to mold, have a small pressure loss, and have a high adsorption rate of a trace gas component.

The first monomer to be graft-polymerized on the substrate is
It is a mixed monomer of an amide-based monomer having an amino group, a secondary amino group or a tertiary amino group and a monomer having a quaternary ammonium group. The amide-based weakly basic monomer is less likely to be hydrolyzed than the ester-based monomer.
Therefore, even if the quaternary ammonium salt is brought into contact with the alkaline aqueous solution used for regenerating the alkaline group, it is difficult to react.
It does not hydrolyze like an acrylic acid ester-based monomer to reduce the ion exchange capacity as an ion exchanger. Examples of the amide-based monomer having a primary amino group, a secondary amino group or a tertiary amino group constituting the mixed monomer include, for example, N, N-dimethylaminopropyl acrylamide (hereinafter, referred to as the following formulas (I) and (II)). , DMAP
(Also referred to as AA).

[0015]

[Chemical 1]

Among them, the above DMAPAA is particularly preferable. In the case of DMAPAA, the acid-base dissociation constant pKa
Is 10.4, whereas ester-based DEAEMA and DMA
Stronger than about 6 of EMA. Therefore, when it is used as a chemical filter, a high removal rate and an adsorption capacity for anionic components that are acidic when dissolved in water such as acidic gas may be expected. The monomer that constitutes the mixed monomer together with the amide-based monomer is a monomer having a quaternary ammonium group. For example, vinylbenzyltriorganoammonium halides represented by the following formulas (III) and (IV) are preferable.

[0017]

[Chemical 2]

In the above formula, Ph represents a benzene ring group, R represents an organo group, and X represents halogen. The organo groups substituting the nitrogen atoms may be the same or different from each other. Among the vinylbenzyltriorganoammonium halides, vinylbenzyltrimethylammonium chloride (VBTAC), vinylbenzyltriethylammonium halide, vinylbenzyltriethanolammonium halide and the like can be particularly mentioned. Above all, VB
Most preferred is TAC. Note that 2-hydroxy-3-methacryloxypropylammonium chloride and dimethylaminoethyl methacrylate-methyl chloride salt not included in the above are not preferable. This is because the ester group is present in the molecule, and the hydrolysis resistance is poor, such as ester decomposition when contacted with an alkaline aqueous solution used for regenerating the quaternary ammonium salt. This chemistry is important when the chemical filter is alkali regenerated and reused.

As described above, when the amide-based weakly basic monomer is mixed with the monomer having a quaternary ammonium group,
Unlike the case of the ester-based weakly basic monomer, even when the concentration of both monomers is high, it is uniformly dissolved in water and an aqueous solution having a high monomer concentration can be obtained. As a result, a polymer obtained by uniformly grafting at a high graft ratio can be obtained. The mixing ratio of the mixed monomer for the graft reaction may be 0.2 to 5 parts by weight, preferably 0.5 to 2 parts by weight, with respect to 1 part by weight of the amide-based monomer. In addition, such a mixed monomer is water 10
It is preferable that the solution is uniformly dissolved in a ratio of 10 to 400 parts by weight with respect to 0 parts by weight.

When the proportion of the monomer having an ammonium group is less than 0.2 part by weight, a high removal rate and an adsorption capacity for an anionic component which is soluble in water such as an acidic gas and exhibits an acidity cannot be expected sufficiently, which is very preferable. Absent. If it exceeds 5 parts by weight, a sufficient graft ratio cannot be obtained, which is not preferable. When the proportion of the monomer having an ammonium group is within the above range, an excellent anion exchanger having a large neutral salt decomposing capacity can be obtained, which is preferable. Radiation is applied to the base material by irradiating it with an electron beam in an inert gas atmosphere. The irradiation dose is 10 to 300 kGy, preferably 50 to 200 k
Gy is preferred. When the irradiation dose is less than 10 kGy, the number of radicals is small and the achieved graft ratio is small, which is not preferable. When it exceeds 300 kGy, the deterioration of the substrate becomes remarkable, which is not preferable.

Next, the substrate thus irradiated with radiation is graft-reacted with the above-mentioned mixed monomer. That is, the both are mixed and reacted at a temperature of 20 to 50 ° C. for 20 minutes to 6 hours. When the monomer having a quaternary ammonium group is used in its halogen chloride state, a regeneration treatment is then performed. Specifically, it is immersed in alkaline ionized water to remove halogen ions. According to such a method, an ion exchanger having an ion exchange capacity of 0.5 to 3.5 meq / g can be obtained. Such ion exchangers can be widely used as woven / nonwoven fabrics, hollow fibers, films, and processed products thereof.

When used as a chemical filter,
The water content greatly affects the gas removal performance. The higher the water content, the better. The amide-based weakly basic monomer has a higher water content in the graft product as compared with the ester-based monomer, and is also excellent in this respect. Further, since the water content of the quaternary ammonium group is high, a combination with an amide weakly basic monomer having a high ratio of the quaternary ammonium group is preferable. According to the method of the present invention, it is possible to increase both the grafting ratio of the quaternary ammonium group and the weak amide base. If the basicity is increased, when used as a chemical filter,
It is possible to obtain a high removal rate and adsorption capacity for anionic components that are acidic when dissolved in water such as acidic gas.

A woven or non-woven fabric, which is a fiber or an aggregate of fibers, is lightweight and easy to mold, has a small pressure loss, and has a high adsorption rate of a trace gas component, and is therefore an optimum material for a chemical filter. is there. If the anion exchanger of the present invention is produced using such a fiber material and the basicity thereof is increased, an anion exchange fiber having a high water content and a large adsorption capacity can be obtained. The ability to remove acidic gas components is extremely excellent, and chemical filters containing this material can be manufactured. The chemical filter may be molded, for example, by the following method. A filter material such as a non-woven fabric that has been grafted is formed into a pleated shape or a corrugated shape, and is attached to the filter frame with an adhesive or the like.

[0024]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited thereto. (Example 1) A non-woven fabric having a basis weight of 60 g / m ^{2 and made} of polyethylene having a diameter of about 20 μm was exposed to 200 electron beams under a nitrogen atmosphere.
After irradiation with kGy, VBTAC, DMAPAA and water were mixed at a weight mixing ratio of 1: 2: 1, and the nonwoven fabric was immersed in the obtained mixed monomer aqueous solution to carry out a graft polymerization reaction. At this time, the mixed monomer solution was uniformly dissolved. 5
When reacted at 0 ° C. for 3 hours, a graft nonwoven fabric having a graft ratio of 230% was obtained.

This grafted nonwoven fabric was immersed in a 4% aqueous sodium hydroxide solution at 60 ° C. for 1 hour to be regenerated, and then the ion exchange capacity was measured. As a result, a strong basic anion exchange nonwoven fabric having a high VBTAC-derived neutral salt decomposition capacity of 1.96 meq / g out of the total exchange capacity of 3.2 meq / g was obtained. When the regeneration of this strongly basic anion exchange nonwoven fabric and the ion exchange capacity measurement were repeated 5 times, the total exchange capacity at the 5th time was 3.17 meq / g and the neutral salt decomposition capacity was 1.95 meq / g. It shows almost the same value as the first time,
It proved to be durable against alkali action.

Comparative Example 1 The same non-woven fabric as in Example 1 was irradiated with the same radiation, and then VBTAC and DEAEMA were applied.
And water were immersed in a monomer aqueous solution in which the weight mixing ratio was 1: 2: 1, and the same graft polymerization reaction was performed.
A graft nonwoven fabric having a graft ratio of 251% was obtained. This grafted non-woven fabric was added to a 4% aqueous sodium hydroxide solution at 60 ° C.
After immersion for a period of time and regeneration, the ion exchange capacity was measured. As a result, the total exchange capacity was as large as 3.5 meq / g, but the neutral salt decomposition capacity derived from VBTAC was 1.
It was as small as 05 meq / g. When the regeneration of the strongly basic anion exchange nonwoven fabric and the ion exchange capacity measurement were repeated 5 times, the total exchange capacity at the 5th time decreased to 2.64 meq / g and the neutral salt decomposition capacity decreased to 0.85 meq / g, It was found that the alkali resistance was low.

(Example 2) The strongly basic anion exchange nonwoven fabric produced in Example 1 was placed in a constant temperature and humidity chamber at 22 ° C and 55% relative humidity, and the water content was measured to be 15.6%. , Showed a high value. When this non-woven fabric was cut into a square 4 cm on a side and about 5 ppm of sulfurous acid gas was passed at 5 liter / min, the initial removal efficiency was 99% or more, which was a very high value. (Comparative Example 2) The strongly basic anion exchange nonwoven fabric produced in Comparative Example 1 was placed in a constant temperature and humidity chamber at 22 ° C and 55% relative humidity, and the water content was measured to be 8.6%. The value was lower than that of 1. When this non-woven fabric was cut into a square of 4 cm on a side and about 5 ppm of sulfurous acid gas was passed at 5 liters / min, the initial removal efficiency was as high as 93%, but it was small compared to the examples.

[0028]

Industrial Applicability According to the present invention, a mixed monomer of an amide monomer having a primary amino group, a secondary amino group or a tertiary amino group and a monomer having a quaternary ammonium group is radiation-grafted on an organic polymer substrate. Then, the halogen ion is removed and regenerated to produce the anion exchanger, so that the process is simple and the production work is also easy. It is highly safe without using chemicals that may worsen the working environment or the global environment. It is easy to increase the water content of the obtained ion exchanger, and excellent anion exchange performance can be obtained. Therefore, it is possible to provide a chemical filter having an excellent effect of removing an acidic substance to be removed. A monomer that does not have an ester bond can be used, has high chemical resistance, and can be used repeatedly by regeneration or the like.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI B01D 53/81 B01J 47/12 E B01J 41/12 C08F 291/00 47/12 C08J 7/18 C08F 291/00 B01D 53/34 A // C08J 7/18 (72) Inventor Mari Katsumine 4-2-1 Honfujisawa, Fujisawa City, Kanagawa Prefecture, Ebara Research Institute, Ltd. (56) Reference JP-A-6-49236 (JP, A) Kaihei 5-111607 (JP, A) JP 5-1912593 (JP, A) JP 5-131120 (JP, A) JP 1-224009 (JP, A) JP 63-135432 ( JP, A) JP 62-25871 (JP, A) JP 54-101791 (JP, A) JP 54-101790 (JP, A) JP-A 8-508758 (JP, A) (58) ) Fields surveyed (Int.Cl. ⁷ , DB name) C08J 5/20 B01D 39/08 B01D 39/14 B01D 39/16 B01D 53/34 B01D 53/81 B01J 41/12 B01J 47/12 C08F 291/00 C08J 7/18

Claims (5)

(57) [Claims] 1. An organic polymer substrate is irradiated with radiation to obtain a first
An anion exchanger comprising a mixture of an amide-based monomer having an amino group, a secondary amino group or a tertiary amino group and a monomer having a quaternary ammonium group, which is graft-polymerized on the organic polymer base material. 2. An organic polymer substrate is irradiated with radiation to obtain a first
A method for producing an anion exchanger, which comprises graft-polymerizing a mixture of an amide-based monomer having an amino group, a secondary amino group or a tertiary amino group and a monomer having a quaternary ammonium group onto the organic polymer substrate. . 3. The method for producing an anion exchanger according to claim 2, wherein the monomer having a quaternary ammonium group is vinylbenzyltriorganoammonium halide. 4. The method for producing an anion exchanger according to claim 2, wherein the organic polymer base material is selected from fibers, woven or nonwoven fabrics which are fiber aggregates, and processed products thereof. 5. A chemical filter containing the anion exchanger according to claim 1 .