JP2010083996A - Manufacturing method for graft polymerization substance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To smoothly progress graft polymerization and to recovery the produced graft polymerization substance by solid/liquid separation in manufacturing the graft polymerization substance by a pre-irradiation method. <P>SOLUTION: In the method, the graft polymerization substance is manufactured by graft-polymerizing a reactive monomer with a substrate comprising a water-soluble polysaccharide and/or its derivative. In the manufacturing method for the graft polymerization substance, the water-soluble polysaccharide and/or its derivative irradiated with radiation is reacted with the reactive monomer in a mixture solvent of a poor solvent of the water-soluble polysaccharide and/or its derivative and water. A 2 or more C alcohol such as ethanol is preferable as the poor solvent and a content of water in the mixture solvent is preferably 10 wt.%, particular preferably 2-5 wt.%. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a graft polymer, and more particularly to a method for obtaining a graft polymer by graft polymerization of a reactive monomer to water-soluble polysaccharides and / or derivatives thereof irradiated with radiation.

  For fly ash discharged from waste incinerators, soil contaminated with hazardous substances, wastes buried in industrial waste final disposal sites, factory effluents, odorous gases emitted from factories and sewage treatment plants, etc. As a trapping material for harmful substances contained, the present applicant has previously made a harmful substance obtained by binding a functional group having a harmful substance capturing ability to a graft chain introduced into a biodegradable water-soluble substrate such as methylcellulose. A collection material was proposed (Patent Document 1). Since this harmful substance collection material uses a biodegradable water-soluble base material as a base material, the load on the environment is small. Further, since the base material is water-soluble, it can be sufficiently diffused into drainage, contaminated soil, odorous substance-containing air, etc., and has an excellent ability to remove harmful substances. Furthermore, because of its high ability to remove harmful substances, it is possible to reduce the amount of harmful substance collection material used, further reduce the burden on the environment, and be economical. .

  In order to produce this hazardous substance-trapping material, first, grafting a reactive monomer onto a biodegradable water-soluble substrate and introducing a graft chain, and capturing the harmful substance in the graft chain portion of the resulting graft polymer. It is produced by reacting a functional group having a function.

In the production of this graft polymer, in Patent Document 1, a substrate such as methylcellulose is irradiated with radiation to generate radicals, and then the irradiated substrate is reacted with a reactive monomer (Patent Document). In one embodiment, it is reacted with glycidyl methacrylate) to obtain a graft polymer. In Patent Document 1, as the reaction solvent, “typically, water, alcohols such as methanol, aprotic polar solvents such as dimethyl sulfoxide, dimethylformamide, ethers, or a mixture thereof are used. In the examples of Patent Document 1, a single solvent of methanol is used.
JP 2008-105025 A

  A method of producing a graft polymer by irradiating a water-soluble substrate with radiation and then grafting a reactive monomer in a reaction solvent (hereinafter referred to as “pre-irradiation method”). As a result of examination on the following, the following was found.

  That is, when methanol or water, which is a good solvent for a water-soluble substrate, is used as a reaction solvent, the graft polymer is generated in a state dissolved in these reaction solvents, and thus cannot be recovered by solid-liquid separation.

  In order to further bind the above-mentioned functional group having the ability to trap harmful substances to the graft chain of the graft polymer, the graft polymer formed in the reaction product liquid is separated from the reaction solvent by solid-liquid separation and once recovered. Although it is advantageous in terms of reaction operation to carry out a reaction for introducing a functional group in the next step on the recovered graft polymer, as described above, a good solvent for a water-soluble substrate such as methanol or water is used as a reaction solvent. In such a case, the graft polymer cannot be recovered by solid-liquid separation.

  On the other hand, when a poor solvent of a water-soluble substrate such as ethanol is used as a reaction solvent, the graft polymerization cannot be advanced by the pre-irradiation method. According to the study of the present inventors, this is because the radical generated by irradiating the water-soluble substrate with radiation does not show a reaction activity in a poor solvent having no affinity for the water-soluble substrate. This is thought to be because the reactive monomer cannot graft polymerize with this radical.

  The present invention solves the above-mentioned conventional problems, and in the production of a graft polymer by the pre-irradiation method, the graft polymer can be recovered by solid-liquid separation after the graft polymerization has proceeded smoothly. It aims at providing the manufacturing method of a polymer.

  As a result of diligent studies to solve the above problems, the present inventors have used the mixed solvent of a poor solvent such as ethanol and water as a reaction solvent in the production of the graft polymer by the pre-irradiation method. I found out that it can be solved.

  The present invention has been achieved on the basis of such findings, and the gist thereof is as follows.

[1] In a method for producing a graft polymer by graft polymerization of a reactive monomer onto a substrate comprising a water-soluble polysaccharide and / or derivative thereof, the water-soluble polysaccharide and / or derivative thereof irradiated with radiation, A method for producing a graft polymer, which comprises reacting with a reactive monomer in a mixed solvent of water and a poor solvent of a water-soluble polysaccharide and / or a derivative thereof.

[2] The method for producing a graft polymer according to [1], wherein the poor solvent is an alcohol having 2 or more carbon atoms.

[3] The method for producing a graft polymer according to [1] or [2], wherein the content of water in the mixed solvent is 10% by weight or less.

[4] In any one of [1] to [3], the water-soluble polysaccharide and / or derivative thereof is at least one selected from the group consisting of natural cellulose, synthetic cellulose, starch, chitosan, and glucose. A method for producing a graft polymer.

[5] The method for producing a graft polymer according to any one of [1] to [4], wherein the reactive monomer is a glycidyl compound.

[6] The method for producing a graft polymer according to any one of [1] to [5], wherein the poor solvent, water, and the reactive monomer are each subjected to deoxygenation treatment.

[7] The method for producing a graft polymer according to any one of [1] to [6], wherein the graft polymer is recovered from the reaction product solution by solid-liquid separation.

  According to the present invention, a water-soluble polysaccharide and / or a derivative thereof is used as a reaction solvent when grafting a reactive monomer to a water-soluble polysaccharide and / or a derivative thereof irradiated with radiation to produce a graft polymer. By using a mixed solvent of the above poor solvent and water, it is possible to easily recover the graft polymer in the reaction product liquid by solid-liquid separation while allowing the graft polymerization to proceed smoothly.

  That is, since the reaction solvent contains water, the radical generated on the water-soluble polysaccharide and / or its derivative by irradiation shows sufficient reaction activity, so that the graft polymerization proceeds smoothly. Since a poor solvent for the water-soluble polysaccharide and / or derivative thereof is contained, the graft polymer based on the water-soluble polysaccharide and / or derivative thereof precipitates as a solid in the reaction solution, and is filtered. Etc., and can be recovered by solid-liquid separation easily.

  Hereinafter, embodiments of the method for producing a graft polymer of the present invention will be described in detail.

  In the method for producing a graft polymer of the present invention, a water-soluble polysaccharide and / or its derivative irradiated with radiation is mixed with a poor solvent of the water-soluble polysaccharide and / or its derivative and water in a reaction solvent. A graft polymer is obtained by reacting with a reactive monomer.

<Water-soluble polysaccharide and / or its derivative>
In the present invention, the water-soluble polysaccharide and / or derivative thereof used as a base material for the graft polymer may be any water-soluble polysaccharide or derivative thereof, and is not particularly limited. Celluloses, water-soluble cellulose derivatives such as alkylcelluloses such as methylcellulose and ethylcellulose, starches and chitosans such as water-soluble salts such as chitosan hydrochloride and acetate, glucose (glucose), etc., preferably alkylcellulose such as methylcellulose Water-soluble cellulose derivatives such as These may be used alone or in combination of two or more.

<Reactive monomer>
The reactive monomer to be graft-polymerized to the water-soluble polysaccharide and / or its derivative is not particularly limited as long as it can be graft-polymerized to radicals generated on the water-soluble polysaccharide and / or its derivative by irradiation. Although there is no limitation, in order to bond a functional group having a toxic substance capturing ability to the graft chain of the obtained graft polymer in order to be used for various drugs, the reactivity with the functional group is required. Those having a hydroxyl group, carboxyl group, aldehyde group, amino group or the like as a reactive functional group can be introduced into the graft chain, such as glycidyl acrylate, glycidyl methacrylate (GMA), glycidyl alcohol, glycidyl ester (for example, Glycidyl alcohol), glycidyl ether, etc. Le compounds, and other allylamine, preferably include glycidyl compounds such as GMA. These reactive monomers may be used individually by 1 type, and may use 2 or more types together.

<Reaction solvent>
In the present invention, as the reaction solvent, a mixed solvent of the above-mentioned water-soluble polysaccharide and / or a poor solvent of its derivative and water is used.

  Here, the poor solvent for the water-soluble polysaccharide and / or derivative thereof is one having low solubility in the water-soluble polysaccharide and / or derivative thereof to such an extent that the graft polymer can exist as a solid after graft polymerization. Examples thereof include alcohols having 2 or more carbon atoms such as ethanol and propanol, and dimethyl sulfoxide. These poor solvents may be used individually by 1 type, and may use 2 or more types together.

  If the content of water in the reaction solvent is too small, the effect of promoting graft polymerization due to the use of water will not be obtained, and if it is too large, the resulting graft polymer will be easily dissolved in the reaction solvent, resulting in solid-liquid separation. It is impossible to collect by the above or the collection rate is lowered. Accordingly, the content of water in the reaction solvent varies depending on the type of poor solvent used, but is preferably 10% by weight or less, for example, 1 to 10% by weight, and more preferably 2 to 5% by weight.

<Deoxygenation treatment>
In the graft polymerization according to the present invention, when oxygen is present in the reaction system, radicals generated on the water-soluble polysaccharide and / or derivative thereof upon irradiation are deactivated by oxygen, and the graft polymerization is inhibited.

  Therefore, it is preferable that the reaction solvent and the reactive monomer to be subjected to the reaction are preliminarily deoxygenated by nitrogen gas ventilation or the like to sufficiently remove dissolved oxygen.

  In this deoxygenation treatment, nitrogen gas aeration (hereinafter referred to as “nitrogen aeration”) may be applied to the mixed solvent after mixing the poor solvent and water, or to the mixed liquid obtained by further mixing the reactive monomer in the mixed solvent. ), The mixing ratio changes due to the evaporation of the solvent and the intended graft polymerization cannot be performed. Therefore, the poor solvent, water and the reactive monomer can be separately subjected to deoxygenation separately before being subjected to the reaction. preferable.

  As this deoxygenation treatment, in addition to nitrogen aeration, other inert gases such as helium gas and argon gas can be ventilated, vacuum degassing by suction using a vacuum pump, etc., but it is particularly economical. Therefore, nitrogen aeration is preferable.

<Radiation>
In the present invention, an electron beam or γ-ray can be used as the radiation.

<Use ratio>
In the present invention, the use ratio of the water-soluble polysaccharide and / or derivative thereof, the mixed solvent, and the reactive monomer is not particularly limited, but the following ranges are preferable.

  The amount of the reactive monomer used is appropriately adjusted according to the target graft polymerization rate. However, if the amount is too small, the function of graft chain introduction may not be sufficiently obtained in the use of the obtained graft polymer. For this reason, it is preferable that the amount of water-soluble polysaccharide and / or its derivative used is 1 or more times, particularly 5 or more times. However, if the amount of the reactive monomer used is too large, the amount of reactive monomer that does not participate in the reaction remains large, which is economically disadvantageous, so that it is 20 weight times or less with respect to the water-soluble polysaccharide and / or its derivative, In particular, it is preferably 10 times by weight or less. In the present invention, it is preferable to obtain a graft polymer having a graft ratio of 10 to 90%, particularly 40 to 60% by using a reactive monomer in such a ratio with respect to the water-soluble polysaccharide and / or its derivative. . Here, the graft ratio is the graft polymerization ratio of the reactive monomer to the water-soluble polysaccharide and / or its derivative, and theoretically [{(weight of the generated graft polymer) − (water-soluble Weight of saccharide and / or derivative thereof)} / (weight of water-soluble polysaccharide and / or derivative used)] × 100.

  If the amount of the mixed solvent of the poor solvent of water-soluble polysaccharide and / or its derivative, which is a reaction solvent, and water is too small, graft polymerization cannot proceed smoothly, and if it is too large, the capacity of the reaction system increases. Since it is uneconomical, it is preferable that the concentration of the reactive monomer in the mixed solution of the mixed solvent and the reactive monomer is 5 to 30% by weight, particularly 10 to 20% by weight.

<Reaction operation, reaction conditions>
In the present invention, the graft polymerization reaction is performed, for example, as follows.

  First, the water-soluble polysaccharide and / or derivative thereof is irradiated with radiation to generate radicals on the water-soluble polysaccharide and / or derivative thereof. Irradiation of the water-soluble polysaccharide and / or derivative thereof is carried out in a vacuum (reduced pressure) atmosphere, or in an insoluble gas atmosphere such as nitrogen, at room temperature or cooled with dry ice. The irradiation dose can be appropriately determined on condition that the water-soluble polysaccharide and / or derivative thereof is a sufficient dose to generate radicals, but is typically 10 to 200 kGy.

  Separately, the poor solvent, water and reactive monomer of the water-soluble polysaccharide and / or derivative thereof used in the reaction are deoxygenated by, for example, nitrogen aeration separately.

  The water-soluble polysaccharide and / or its derivative irradiated with the poor solvent, water, and the reactive monomer which were subjected to deoxygenation treatment were mixed immediately before mixing with the water-soluble polysaccharide and / or its derivative irradiated with radiation. And heat to react.

  The heating temperature depends on the reactivity of the reactive monomer, but is typically 40 to 70 ° C, preferably 40 to 50 ° C. The reaction time is 30 minutes to 24 hours, but can be determined depending on the reaction temperature and the required graft rate. It is a factor which determines a reaction rate with reaction temperature and reaction time, and can be suitably determined similarly.

  After the reaction, the graft polymer is recovered by solid-liquid separation by filtration or the like, and dried by vacuum drying or the like to obtain the target graft polymer.

  In addition, after irradiating water-soluble polysaccharide and / or its derivative with radiation, this water-soluble polysaccharide and / or its derivative is charged into a mixed solution in which a reactive monomer is mixed in a mixed solvent until graft polymerization is performed. The time should not be too long because the radicals disappear. That is, if the time until the water-soluble polysaccharide and / or derivative thereof after irradiation is subjected to graft polymerization is long, the graft ratio decreases. Accordingly, the water-soluble polysaccharide and / or derivative thereof is preferably subjected to graft polymerization within 24 hours after irradiation.

<Application>
The graft polymer produced by the method of the present invention is useful as an intermediate for the harmful substance-collecting material described in Patent Document 1 described above. Further, the graft chain of this graft polymer has a harmful substance-trapping ability. It is possible to produce a harmful substance trapping material useful for various applications by reacting the functional group.

  In this case, a functional group capable of efficiently capturing harmful substances contained in a treatment target such as waste water, contaminated soil, and odor-containing air is selected as the functional group having the ability to capture harmful substances. For example, one or more functional groups shown in Table 1 below are selected.

  In order to introduce these functional groups into the graft chain, for example, the graft polymer may be immersed in an aqueous solution such as a salt containing the target functional group or a solution of isopropyl alcohol (IPA) and heated as necessary. .

  Hereinafter, the present invention will be described in more detail with reference to Examples, Comparative Examples and Reference Examples.

  In the following, “SM25 dry product” manufactured by Shin-Etsu Chemical Co., Ltd. is used as methylcellulose, reagent grades manufactured by Tokyo Chemical Industry Co., Ltd. are used as GMA, and Wako Pure Chemical Industries, Ltd. is used as ethanol. A reagent grade was used.

In addition, the reaction results are obtained by drying the solid content obtained by filtering the reaction product solution, measuring the weight (recovered amount), and recovering from the weight of the methyl cellulose subjected to the reaction (test amount) by the following formula: The rate was calculated and compared with this recovery value. Here, when the graft polymerization proceeds smoothly and the produced graft polymer can be separated by filtration, the test amount can be regarded as the amount of the base material of the produced graft polymer, and the recovered amount Since it can be regarded as the amount of the graft polymer produced, it can be said that the recovery rate is almost equal to the graft rate.
Recovery rate (%) = {(recovered amount−test amount) / test amount} × 100

[Examples 1 and 2 and Comparative Example 1]
Radicals were generated by irradiating 2 g of methylcellulose with 60 kGy of electron beam under nitrogen substitution conditions.
A liquid mixture obtained by mixing GMA, ethanol, and pure water in the proportions shown in Table 2 within 24 hours after electron beam irradiation (in Comparative Example 1, use water). 1) It was added to 100 g and heated at 50 ° C. for the time shown in Table 2 under vacuum conditions. The GMA, ethanol and water used were each deoxygenated in advance by nitrogen aeration for 2 hours or more.

  After the reaction, the reaction product was collected by filtration through glass fiber filter paper, dried under reduced pressure, the weight of the product (grafted polymer) was measured, the recovery rate was calculated, and the results are shown in Table 2.

From Table 2, it can be seen that by using a mixed solvent of ethanol and water, the graft polymerization can proceed and the produced graft polymer can be recovered by solid-liquid separation.
In Comparative Example 1, the recovery rate is negative because solid-liquid separation and recovery could not be performed due to partial dissolution of methylcellulose and technical loss due to the absence of water.

[Examples 3 to 6, Reference Example 1]
In Example 1, the reaction was carried out in the same manner except that the electron beam irradiation amount to methylcellulose was 100 kGy, and the mixing ratio of GMA, ethanol and pure water was the ratio shown in Table 3, and the recovery rate was similarly set. The results are shown in Table 3.

  From Table 3, it can be seen that the graft polymer can be recovered by solid-liquid separation by using 10 wt% or less of water with respect to the total of ethanol and water.

[Reference Examples 2 to 6]
In Example 1, the amount of electron beam irradiation to methylcellulose was 100 kGy, and the deoxygenation treatment by nitrogen aeration of GMA, ethanol, and pure water was performed for the time shown in Table 4 with respect to the mixture of GMA, ethanol, and pure water The reaction was carried out in the same manner except that the heating time was changed to the time shown in Table 4, the recovery rate was examined in the same manner, and the results are shown in Table 4.

  From Table 4, it can be seen that when GMA, ethanol and water are mixed and then nitrogen aeration is performed, the mixing result of ethanol and water shifts and the reaction result is not stable.

Claims (7)

In a method for producing a graft polymer by graft polymerization of a reactive monomer to a substrate comprising a water-soluble polysaccharide and / or a derivative thereof,
Graft polymerization characterized by reacting a water-soluble polysaccharide and / or derivative thereof irradiated with radiation with a reactive monomer in a mixed solvent of a poor solvent of the water-soluble polysaccharide and / or derivative and water. Manufacturing method.   The method for producing a graft polymer according to claim 1, wherein the poor solvent is an alcohol having 2 or more carbon atoms.   3. The method for producing a graft polymer according to claim 1, wherein the water content in the mixed solvent is 10% by weight or less.   The water-soluble polysaccharide and / or derivative thereof according to any one of claims 1 to 3, wherein the water-soluble polysaccharide and / or derivative thereof is at least one selected from the group consisting of natural cellulose, synthetic cellulose, starch, chitosan, and glucose. A method for producing a graft polymer.   The method for producing a graft polymer according to any one of claims 1 to 4, wherein the reactive monomer is a glycidyl compound.   The method for producing a graft polymer according to any one of claims 1 to 5, wherein the poor solvent, water, and a reactive monomer are used after being deoxygenated.   The method for producing a graft polymer according to any one of claims 1 to 6, wherein the graft polymer is recovered from the reaction product solution by solid-liquid separation.