JPH0443697B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a urea adsorbent, and particularly to a novel polymeric urea adsorbent useful for artificial kidneys.

[Problems to be solved by conventional technology and invention]

Artificial kidneys currently in use include dialysis-type, filtration-type, adsorption-type, and enzyme-immobilized artificial kidneys.

However, all of these have advantages and disadvantages, and no drug has been developed that is satisfactory for patients with chronic or acute renal failure.

For example, dialysis-type artificial kidneys are currently the most popular, but new dialysate is always required. In addition, these devices are generally large in size, resulting in the inconvenience that renal failure patients are confined in the hospital for long periods of time.

Filtration-type artificial kidneys have a major drawback in that serum containing useful components is also discarded.

Enzyme-immobilized artificial kidneys have been in particular progress in development recently, but there is a problem with the inactivation of the enzyme activity during or after urease immobilization, and its performance also depends on the surrounding environment such as temperature and acidity. Easily influenced by the environment.

Adsorption-type artificial kidneys are small, lightweight, and simple, but they use activated carbon as an adsorbent, and although they are effective for organic wastes, they are completely ineffective against urea, which is the largest component excreted in urine. It has no effect. Currently, the search for urea removal substances is the most important issue in adsorption artificial kidneys. For example, there are applications of oxidized starch (Kobunshi Ronshu, Vol. 39, p. 629), urea adsorbents made by reacting formaldehyde or glyoxal with a polymer having a hydrazide group (Japanese Patent Application Laid-open No. 1983-69489), etc. However, the reality is that it has not yet reached the stage of practical use.

[Means for solving problems]

As a result of intensive studies on high-performance urinary adsorbents to solve the above-mentioned problems, the present inventor found that a polymer containing both carboxyl groups and imidazole groups is useful as a urea removal substance, and polyoxyalkylene glycol The inventors discovered that a polymer containing a derivative as a constituent component has a higher urea adsorption ability, leading to the present invention. That is, the present invention provides: (1) a carboxyl group and an imidazole group represented by general formula (1); (In the formula, R ₁ represents hydrogen or a hydrocarbon group having 5 or less carbon atoms.) A polymer of ethylenically unsaturated monomers that contains as a constituent component and is crosslinked with a crosslinking agent as necessary. , a polymer urea adsorbent characterized in that the ratio of the number of carboxyl groups to the number of imidazole groups (carboxyl group/imidazole group) is from 0.1 to 8.0.

(2) Carboxyl group, imidazole group represented by general formula (1) (In the formula, R ₁ represents hydrogen or a hydrocarbon group having 5 or less carbon atoms.), and General formula (2) [-(CH ₂ -) _o O-] _n R ₂ (2) (In the formula, n is Contains a polyoxyalkylene glycol derivative group represented by an integer of 2 to 5, m represents an integer of 3 or more, and _R2 represents hydrogen or a methyl group as a constituent component, and can be crosslinked with a crosslinking agent as necessary. A polymer of ethylenically unsaturated monomers having a ratio of the number of carboxyl groups to imidazole groups (carboxyl group/imidazole group) of 0.1.
The present invention relates to a polymer urea adsorbent characterized in that it has a molecular weight of 8.0 to 8.0.

The urea adsorbent of the present invention can be easily produced by the following method. That is, an ethylenically unsaturated monomer having a carboxyl group or a group convertible to a carboxyl group and an ethylenically unsaturated monomer having an imidazole group shown in general formula (1). It is produced by radical polymerization by mixing at a certain molar ratio or by adding other ethylenically unsaturated monomers. The manufacturing method is arbitrary and is not particularly limited, and it can be manufactured by any of the bulk polymerization method, solution polymerization method, emulsion polymerization method, and suspension polymerization method.

Examples of the ethylenically unsaturated monomer having a carboxyl group include acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, 2-pentenoic acid, 2-ethyl acrylic acid, andieric acid, tiglic acid, 3,3- Dimethyl acrylic acid, 3-propylacrylic acid, 3-isopropylacrylic acid, trimethylacrylic acid, 2-butylacrylic acid, 3-butylacrylic acid, 2-methyl-2-hexenoic acid, 2,3-diethylacrylic acid, 2 - Acrylic unsaturated monomers such as octenoic acid, 2-nonenoic acid, 2-decenoic acid, α-acetoxyacrylic acid, o-vinylbenzoic acid, p-vinylbenzoic acid,
3-vinylsalicylic acid, 4-vinylsalicylic acid,
Styrenic unsaturated monomers such as 5-vinylsalicylic acid, 3-vinylacetylsalicylic acid, 4-vinylacetylsalicylic acid, and 5-vinylacetylsalicylic acid; Examples include functional unsaturated monomers, which can be used singly or in combination of two or more.

Ethylenically unsaturated monomers having a group convertible to a carboxyl group include acid halides, acid anhydrides, alkyl esters, acid amides,
Acid imidides, acid hydrazides, acid inorganic salts, α-angiericalactone, α-methylene-γ-
Unsaturated lactones such as butyrolactone and 2(5H)-furanone, unsaturated nitriles such as acrylonitrile and methacrylonitrile, etc. can also be used.
After polymerization, any of them can be converted into carboxyl groups by hydrolysis treatment. It is also possible to introduce a carboxyl group by an oxidation reaction after polymerization, but this causes undesirable side reactions such as cleavage of the main chain and ring-opening reaction of the imidazole group.
This is not preferred in the present invention.

The ethylenically unsaturated monomer having an imidazole group is, for example, 1-vinylimidazole, 2-vinylimidazole, 4-vinylimidazole, 1
-Methyl-2-vinylimidazole, 1-methyl-5-vinylimidazole, 1-ethyl-5-vinylimidazole, 1-propyl-5-vinylimidazole, 1-butyl-5-vinylimidazole, etc. One type or a combination of two or more types can be used.

First, an acylimidazole is synthesized from an ethylenically unsaturated monomer having a carboxyl group or an ethylenically unsaturated monomer having a group convertible to a carboxyl group, and an ethylenically unsaturated monomer having an imidazole group, A method of converting this product into free carboxyl groups and imidazole groups by polymerizing it and hydrolyzing it after the polymerization is also effective and can be used.

In the present invention, other ethylenically unsaturated monomers can also be used in the production of the polymer if necessary, and even if they are carboxylic acid derivatives, they need to be converted into carboxyl groups after polymerization. For example, ethylene, propylene, 1-butene, 2-butene, 1-hexene, 2
-ethyl-1-butene, 1-methylcyclopentene, 1-heptene, 2-heptene, 2-methyl-
1-hexene, cycloheptene, 1-octene,
Olefinic unsaturated monomers such as 2-octene, 1-nonene, 1-butene, 2-nonene, 3-nonene, 1-phenyl-2-pentene, α-pinene, β-pinene, chloroethylene, promoethylene ,
Halogenated ethylenically unsaturated monomers such as 1,1-dichloroethylene, 1,2-dichloroethylene, trifluoroethylene, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o-ethylstyrene, m -ethyl styrene, p
-ethylstyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, m-chloromethylstyrene, p-chloromethylstyrene, o
-methoxystyrene, m-methoxystyrene, p
-methoxystyrene, o-nitrostyrene, m-
Styrenic unsaturated monomers such as nitrostyrene, p-nitrostyrene, o-cyanostyrene, m-cyanostyrene, p-cyanostyrene, methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether, n- Vinyl ether unsaturated monomers such as butyl vinyl ether, sec-butyl vinyl ether, t-butyl vinyl ether, phenyl vinyl ether, methyl vinyl ketone, acetoxy vinyl ketone, ethyl vinyl ketone, n-propyl vinyl ketone, i-propyl vinyl ketone, Vinyl ketone unsaturated monomers such as phenyl vinyl ketone,
Vinyl ester unsaturated monomers such as vinyl acetate, ethoxyvinyl acetate, vinyl propionate, vinyl butyrate, vinyl laurate, vinyl palmitate, vinyl stearate, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, n-amyl (meth)acrylate, n-hexyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate , (meth)decyl acrylate, (meth)dodecyl acrylate, (meth)
(meth)acrylic acid ester monomers such as oleyl acrylate and glycidyl (meth)acrylate;
In addition, monomers such as maleic anhydride, acrylonitrile, and acrylamide can be used as required, and one or more of these monomers can be used.

In particular, as other ethylenically unsaturated monomers, general formula (3) or (4) (In the formula, n is an integer of 2 to 5, m is an integer of 3 or more, R ³ is hydrogen or a methyl group, and R ⁴ is hydrogen or a hydrocarbon group having 1 to 10 carbon atoms.) When a radically polymerizable polyoxyalkylene glycol derivative is used in the production of a polymer, a polymer containing a polyoxyalkylene glycol derivative group represented by general formula (2) as a constituent component can be obtained.

The radically polymerizable polyoxyalkylene glycol derivative represented by the general formula (3) used in the present invention is, for example, polyoxyethylene glycol mono(meth)acrylate, polyoxytrimethylene glycol (meth)acrylate, polyoxytetramethylene glycol mono (meth)acrylate, ω-methoxypolyoxyethylene glycol mono(meth)acrylate, ω-methoxypolyoxytrimethylene glycol mono(meth)acrylate, ω-methoxypolyoxytetramethylene glycol mono(meth)acrylate, and general The radically polymerizable polyoxyalkylene glycol derivative represented by formula (4) is, for example, α-(p-
vinylbenzyloxy)-polyoxyethylene glycol, α-(p-vinylbenzyloxy)-polyoxytrimethylene glycol, α-(p-vinylbenzyloxy)-polytetramethylene glycol,
α-(p-vinylbenzyloxy)-ω-methoxypolyoxyethylene glycol, α-(p-vinylbenzyloxy)-ω-methoxypolyoxytrimethylene glycol, α-(p-vinylbenzyloxy)-ω-methoxy It is polyoxytetramethylene glycol.

The radically polymerizable polyoxyalkylene glycol derivative represented by general formula (3) or (4) can be used simultaneously with other ethylenically unsaturated monomers, and if necessary, one or more types can be used. can be used.

By introducing the polyoxyalkylene glycol derivative represented by the general formula (2) into the urea adsorbent of the present invention as a constituent component, it is possible to further exhibit urea adsorption ability due to the synergistic effect with the carboxyl group and imidazole group. can. The number average molecular weight of the radically polymerizable polyoxyalkylene glycol derivative represented by the general formula (3) or (4) used in the present invention is 120 or more, preferably 200 or more; No synergistic effects can be expected.

In the production of the polymeric urea adsorbent in the present invention, a crosslinking agent can also be used if necessary. As the crosslinking agent, for example, divinylbenzene, ethylene glycol (meth)acrylate, polyoxyethylene glycol (meth)acrylate, polydimethylsiloxane di(meth)acrylate, polyamide di(meth)acrylate, etc. can be used. The amount of the crosslinking agent to be used is 0.01% to 50% by weight based on the total weight, and if it is more than that, the lubricity of the produced urea adsorbent with respect to water will be significantly lowered, which is not preferable. Moreover, it is an absolute condition that the urea adsorbent of the present invention is insoluble in water, and therefore, in the case of a polymer that is soluble in water, it is necessary to use a crosslinking agent to make it insoluble.
Furthermore, even if a crosslinking agent is not used, insolubilization can be achieved by increasing the amount of other ethylenically unsaturated monomers, and olefinic unsaturated monomers and styrenic unsaturated monomers are particularly effective. be.

An example of manufacturing the urea adsorbent of the present invention will be shown. for example,
An example of the solution polymerization method is to dissolve equimolar amounts of methyl methacrylate, 1-vinylimidazole, acrylic acid, polyoxyethylene glycol monomethacrylate, and 1/10 molar equivalent of ethylene glycol dimethacrylate in a solvent, Polymerization is carried out using a polymerization initiator and stirring under a nitrogen stream. After the polymerization is completed, the mixture is poured into water to precipitate the polymer, followed by washing, drying, and pulverization to prepare a polymeric urea adhesive. The structure of the polymeric urea adsorbent is considered to be good, as the ratio of carboxyl groups to imidazole groups is considered to be 1 from the charging ratio, and the component represented by general formula (2) is 58% by weight of the total weight. It shows excellent urea adsorption function. In the present invention, the charged amount of an ethylenically unsaturated monomer having a carboxyl group or an ethylenically unsaturated monomer having a group convertible to a carboxyl group,
The charged amount of ethylenically unsaturated monomer having an imidazole group is 5% by weight of the total charged amount, respectively.
If either one is less than this, the urea adsorption ability is poor and is not effective.

The ratio of the number of carboxyl groups to the number of imidazole groups contained in the adsorbent in the present invention is r ₁ =(number of carboxyl groups)/(number of imidazole groups), and is preferably r ₁ =0.1 to 8. ₁ = 2 to
0.5 and most preferably r ₁ =1.

When r ₁ =1, the urea adsorbent of the present invention exhibits the most effective urea adsorption ability.

The urea adsorption capacity decreases both when r ₁ is smaller than 0.1 and when it is larger than 8.

By introducing the component represented by general formula (2) into this product, it becomes possible to further improve the urea adsorption ability. For this purpose, the component represented by general formula (2) must be at least 2% by weight or more than 70% by weight of the total weight.
It is as follows. If it is less than 2% by weight, the effect cannot be expected.

Moreover, the water absorption of the produced urea adsorbent increases to 70% by weight or more, causing inconvenience in handling.

A polymerization initiator is used in producing the urea adsorbent, but there is no particular limitation, and any of azo compounds, peroxides, redox initiators, etc. can be used. For example, azo compounds include α,α'-azobisisobutyronitrile, 2,2'-azobis-(2,4-dimethylvaleronitrile), and peroxides include:
dibenzoyl peroxide, lauroyl peroxide, di-t-butyl peroxide, dicumyl peroxide, t-butyl hydroperoxide,
Examples include diisopropyl peroxide carbonate, and redox initiators include hydrogen peroxide-Fe ²⁺ salt, persulfate-sodium bisulfite,
Examples include cumene hydroperoxide-Fe ²⁺ salt, benzoyl peroxide-dimethylaniline, and the like.

The solvent used in the solution polymerization method is not limited in any way as long as it can dissolve the monomer and does not inhibit polymerization, such as N,
Amide solvents such as N'-dimethylformamide and N,N'-dimethylacetamide, aromatic hydrocarbons such as benzene, toluene and xylene, ester solvents such as methyl acetate, ethyl acetate, propyl acetate and butyl acetate, methanol , ethanol, isopropyl alcohol, n-propyl alcohol,
Alcohol solvents such as n-butanol, isobutanol, sec-butanol and t-butanol, and ketone solvents such as acetone, methyl ethyl ketone and diethyl ketone are used.

In order to obtain spherical polymer particles, suspension polymerization or emulsion polymerization can be used. In these cases, polymerization can be carried out using water as a solvent and a dispersion stabilizer or surfactant. It is possible.
(Japanese Unexamined Patent Publication No. 1983-55009, Japanese Patent Application No. 171760) The molecular weight of the polymer of the adsorbent of the present invention is 3000 to 3000.
1 million, preferably 5,000 to 100,000.

The urea adsorbent produced as described above can be used as an adsorbent as is,
If necessary, it may be used as a urea adsorbent after carrying out a surface modification reaction, coating with heparin or albumin, plasma treatment, or the like.

[Effect]

The polymer urea adsorbent of the present invention has a high urea adsorption capacity (100 mg/dl), and by adding 0.5 g of the urea adsorbent to 50 ml of urea aqueous solution and soaking it for 2 hours, the urea concentration can be reduced to 25 mg. /dl), which can be applied to adsorption-type artificial kidneys and sensors.

〔Example〕

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples.

Example 1 Acrylic acid 7.5g, 1-vinylimidazole 9.4g
g, 2 g of ethylene glycol methacrylate,
α,α′-Azopisisobutyronitrile (AIBN)
0.1 g was dissolved in 100 ml of N,N'-dimethylformaldehyde (DMF) and polymerized at 110° C. for 2 hours under a nitrogen stream. Thereafter, a small amount of AIBN was added, and DMF was distilled off under reduced pressure and heating to complete the polymerization reaction. The polymerization residue was placed in the water from step 1 and stirred at room temperature for 1 hour, and then the polymerization product was separated using a centrifuge, which was further washed twice with water, twice with methanol, and once with acetone. , 50℃ under reduced pressure
I let it dry for a day. After drying, grind to an average particle size of approx.
100μ particles were obtained. The composition of the polymer was determined by infrared absorption spectrum to show carboxyl groups (3300 to 300
cm ^-1 , 1750cm ^-1 ) and imidazole group (1550,
1490, 1325 cm ^-1 ) was confirmed, and the ratio of the number of carboxyl groups to the number of imidazole groups is considered to be 1 from the amount charged. The carboxyl groups and imidazole groups interact weakly within the polymer, but are arranged randomly in consideration of the absorption range of the infrared absorption spectrum. Further, the polymer is a crosslinked polymer and is insoluble in all solvents, but has a good degree of swelling in water.

The polymer particles were used as they were as a urea adsorbent, and the amount of urea adsorbed was measured as follows.

0.5g of the adsorbent in 50ml of 100ml urea/dl aqueous solution
and stirred at 20°C for 2 hours. Thereafter, the mixture was centrifuged, and the concentration of urea in the supernatant was determined colorimetrically by the diacetyl method. (Manufactured by Hitachi, Ltd.
Colorimetric determination was carried out at 480 nm using a 150-20 spectrophotometer. ) As a result, it was found that the urea concentration had decreased to 30mg urea/dl. For comparison, when activated carbon was used instead of the adsorbent, the amount decreased to only 95 mg urea/dl.

It has thus been found that the ratio of the number of carboxyl groups to the number of imidazole groups is 1, and that a polymer composed only of both has a very high urea adsorption function.

In this example, the infrared absorption spectrum was measured using a model A-102 infrared spectrophotometer manufactured by JASCO Corporation.
Ultraviolet/visible absorption spectrum is 150 manufactured by Hitachi, Ltd.
Measurements were made using a -20 type ultraviolet/visible spectrophotometer.

Example 2 10 g of 1-vinylimidazole and 11.0 g of methacrylic acid chloride were added to 50 ml of toluene and stirred at room temperature for 1 hour to form a white precipitate. This white precipitate is a methacryloyl imidazole salt, which is a 1:1 salt of methacryloyl group and 1-vinylimidazole. The imidazole salt was filtered and dissolved in 100 ml of DMF, to which were added 1 g of divinylbenzene and 0.1 g of AIBN, and polymerization was carried out at 110° C. for 2 hours. Thereafter, a small amount of AIBN was added, and DMF was distilled off under reduced pressure and heating to complete the polymerization reaction. The polymerization residue was placed in water from Step 1 and stirred at room temperature for 5 hours, and then neutralized by adding sodium hydrogen carbonate until no carbon dioxide was released. At this point, the carboxyl group and imidazole group were liberated, and the presence of the carboxyl group and imidazole group was confirmed by infrared absorption spectrum. Thereafter, separation, purification, drying, and powder frame were performed in the same manner as in Example 1 to obtain a urea adsorbent. The polymer contains carboxyl groups and imidazole groups, and the ratio is thought to be 1 based on the charging ratio.It is also a polymer crosslinked with divinylbenzene, and is insoluble in all solvents, but has a high degree of swelling in water. is in good condition.
A urea adsorption test was conducted using the adsorbent. As a result, it was found that the urea concentration had decreased to 30 mg urea/dl. In this way, it has been found that a urea adsorbent obtained by first synthesizing a salt from methacrylic acid chloride and 1-vinylimidazole and then polymerizing it also has a very high urea adsorption capacity.

Example 3 1-vinylimidazole 10g, acrylic acid 7.9g
g, 20 g of polyoxyethylene glycol monomethacrylate (Blenmar PE350, number average molecular weight 400, manufactured by NOF Corporation), 2 g of ethylene glycol dimethacrylate, and 0.1 g of AIBN were dissolved in 100 ml of DMF, and a urea adsorbent was added in the same manner as in Example 1. It was adjusted. According to the infrared absorption spectrum, the adsorbent contains carboxyl groups, imidazole groups, and hydroxyl groups (3500 to 3300
cm ^-1 ) was confirmed, and the ratio of carboxyl groups to imidazole groups was 1 depending on the preparation ratio.
It is a polymer in which the polyoxyethylene glycol derivative is present at 50% by weight of the total weight. Furthermore, it is a crosslinked polymer and is insoluble in all solvents, but
The water swelling property is good and better than that of Example 1. When a urea adsorption test was conducted using the adsorbent in the same manner as in Example 1, it was found that the adsorption amount was reduced to 25 mg urea/dl. Thus, it can be seen that when a polyoxyethylene glycol derivative is contained, the urea adsorption ability is improved.

Example 4 2 g of methacrylic acid, 2 g of 4-vinylimidazole, polyoxyethylene glycol monomethacrylate (Blemmer PE350, number average molecular weight 400,
(manufactured by NOF Corporation), 4.2g, ethylene glycol dimethacrylate 1.1g, AIBN 0.05g in 100ml
A urea adsorbent was prepared by dissolving it in DMF and using the same method as in Example 1. By infrared absorption spectrum,
The adsorbent contains a carboxyl group, an imidazole group,
It was confirmed that hydroxyl groups and hydroxyl groups were contained, and it was further confirmed that a free -NH group (3210 cmp ^-1 , sharp absorption) was present. This polymer is a polymer in which the ratio of carboxyl groups to imidazole groups is 1 depending on the charging ratio, and the polyoxyethylene glycol derivative is present in an amount of 50% by weight of the total weight. Furthermore, it is a crosslinked polymer and is insoluble in all solvents, but has good swelling properties in water. When a urea adsorption test was carried out using the adsorbent in the same manner as in Example 1, it was found that the urea adsorption was reduced to 37 mg urea/dl. Thus, it can be seen that even when 4-vinylimidazole is used as the unsaturated monomer having an imidazole group, the urea absorbent of the present invention exhibits high adsorption capacity.

Example 5 5 g of methyl methacrylate, 4.7 g of 1-vinylimidazole, 3.6 g of acrylic acid, 1 g of ethylene glycol dimethacrylate, and 0.1 g of AIBN.
A urea adsorbent was prepared by dissolving in 100 ml of DMF and using the same method as in Example 1. Infrared absorption spectra revealed that the adsorbent contains carboxyl groups, imidazole groups, and methyl methacrylate polymerization residues (C=O, 1735 cm
^-1 ), and it is a polymer composed of carboxyl groups, imidazole groups, and methyl methacrylate polymer residues in a 1:1:1 ratio depending on the charging ratio. The polymer is a crosslinked polymer and is insoluble in all solvents, but has good swelling properties in water. When a urea adsorption test was conducted using the adsorbent in the same manner as in Example 1, 35
It was found that the concentration had decreased to mg urea/dl.

In addition, using 3.2 g of vinyl acetate instead of the above methyl methacrylate, a polymer in which the number of carboxyl groups, the number of imidazole groups, and the number of vinyl acetate polymerization residues were in a 1:1:1 ratio was synthesized by the same method. A urea adsorbent was prepared. When a urea adsorption test was conducted using the adsorbent in the same manner as in Example 1, it was found that the adsorption amount was reduced to 38 mg urea/dl. Thus, it can be seen that the urea adsorbent of the present invention exhibits high adsorption capacity even when other ethylenically unsaturated monomer polymerization residues are present in addition to carboxyl groups and imidazole groups.

Example 6 30 g of styrene, 9.4 g of 1-vinylimidazole,
A urea adsorbent was prepared in the same manner as in Example 1 by dissolving 7.5 g of acrylic acid and 0.1 g of AIBN in 100 ml of DMF.
The adsorbent is a non-crosslinked polymer and is soluble in solvents such as DMF and dimethylacetamide, but is soluble in water,
It is a polymer that is insoluble in methanol and ethanol. Further, the number average molecular weight of the adsorbent is about 12,000, and the presence of carboxyl groups and imidazole groups was confirmed by infrared absorption spectrum, and their absence is considered to be 1 based on the charging ratio. When a urea adsorption test was carried out using the adsorbent in the same manner as in Example 1, it was found that the adsorption amount had decreased to 41 mg urea/dl. The adsorbent used in this example is a non-crosslinked polymer whose main component is polystyrene, which has a higher swelling property in water than a crosslinked polymer, and also has excellent urea adsorption ability. I understand.

Comparative example 1-vinylimidazole 10g, ethylene glycol dimethacrylate 1g, AIBN 0.03g
It was dissolved in 50 ml of DMF and polymerized in the same manner as in Example 1 to prepare a urea adsorbent. When a urea adsorption test was conducted using the adsorbent in the same manner as in Example 1,
The urea concentration remained 100 mg urea/dl even after the test, and no change was observed. It was found that the polymer had no carboxyl groups, only imidazole groups, and had no urea adsorption ability at all. Further, although this polymer is insoluble in all polymers, it also has poor swelling property in water and is not suitable as a urea adsorbent. Also, above 1-
A urea adsorbent was prepared by polymerizing in the same manner as in Example 1 using 10 g of acrylic acid instead of vinyl imidazole. When a urea adsorption test was carried out using the adsorbent in the same manner as in Example 1, it was found that it had very high hygroscopicity and was difficult to handle, and that the urea concentration could only be reduced to 60 mg urea/dl. Divided. This polymer has no imidazole group and only carboxyl groups.

These facts indicate that polymers containing only carboxyl groups or only imidazole groups are unsuitable as urea adsorbents in the present invention.

〔Effect of the invention〕

The polymer urea adsorbent of the present invention contains both a carboxyl group and an imidazole group,
It has a high-performance urea function and can be applied to all fields that require urea adsorption and separation, and is particularly applicable to adsorption-type artificial kidneys and sensors.

Claims (1)

[Claims] 1. Carboxyl group and imidazole group represented by general formula (1) (In the formula, R ₁ represents hydrogen or a hydrocarbon group having 5 or less carbon atoms.) A polymer of ethylenically unsaturated monomers that contains as a constituent component and is crosslinked with a crosslinking agent as necessary. , the ratio of the number of carboxyl groups to the number of imidazole groups (carboxyl group/imidazole group) is
A polymer urea adsorbent characterized by having a molecular weight of 0.1 to 0.8. 2 carboxyl group, imidazole group represented by general formula (1) (In the formula, R ₁ represents hydrogen or a hydrocarbon group having 5 or less carbon atoms.), and General formula (2) [-(CH ₂ -) _o O-] _n R ₂ (2) (In the formula, n is Contains a polyoxyalkylene glycol derivative group represented by an integer of 2 to 5, m represents an integer of 3 or more, and _R2 represents hydrogen or a methyl group as a constituent component, and can be crosslinked with a crosslinking agent as necessary. A polymer of ethylenically unsaturated monomers, the ratio of the number of carboxyl groups to the number of imidazole groups (carboxyl group/imidazole group)
is from 0.1 to 8.0.