JP5901053B2 - Water-soluble polymer and method for producing the same - Google Patents

Description

The present invention is characterized by being produced by irradiating visible light to a solution composed of an aqueous medium containing essentially one or more water-soluble monomers having a vinyl group, an organic dye and a peroxide. It relates to a polymer.

  The photopolymerization method is an existing technology for obtaining polymers, but the technology to photopolymerize and cure photocurable resins is an important method in various industries such as the electric / electronic market, automobile, optics, and medical fields. It has become. A major feature of photopolymerization is that the reaction occurs rapidly by light irradiation in a specific wavelength range. In addition to shortening the reaction time and controlling the reaction, selecting a photoinitiator that can start the reaction with an inexpensive light source has the advantage of reducing the investment in equipment.

The photopolymerization technique is a technique mainly used for the polymerization of a water-insoluble monomer, but there is an example applied to the polymerization of a water-soluble monomer. As a production technique for a water treatment flocculant, a method for producing a high molecular weight acrylic polymer using a movable belt (see Patent Document 1) and a technique for continuous photopolymerization of a water-soluble vinyl monomer are disclosed ( Patent Document 2). These patent documents clearly state that when photopolymerization technology is used for the polymerization of water-soluble monomers, it is possible to reduce residual monomers, achieve high-efficiency reactions through continuous production, and produce high molecular weight polymers. Has been.
JP-A-61-155406 JP-A 61-221202

A water-soluble polymer using several photopolymerization techniques has been proposed so far by taking advantage of the photopolymerization in the production of the water-soluble polymer as described above (see Patent Documents 3, 4, and 5). The photopolymerization initiators used in these are those in which photolysis proceeds mainly by light irradiation in the ultraviolet region, such as benzoin derivatives and azo compounds, and the reaction starts.
Japanese Patent Laid-Open No. 10-231309 JP 2002-348303 A JP 2003-82596 A

  When using a photopolymerization initiator that initiates reaction with light in the ultraviolet region, it is necessary to use a light source that emits ultraviolet light. Ultraviolet rays are risk factors such as pigmentation in the skin, wrinkles, cancer, and cataracts in the eyeball, and it is not preferable in the working environment to industrially use a light source that emits ultraviolet rays.

From the viewpoint of safety, a method using a riboflavin / fluorescent light active continuous polymerization system is being studied as a photopolymerization method that can also use light energy in the visible region, but the obtained polymer has a low reaction rate and is a satisfactory product. Is not obtained (see Patent Document 6).
JP 63-135403 A

The present inventors have proposed a method for producing a polyacrylamide gel for electrophoresis by photopolymerization using a redox polymerization initiator composed of an oxidizing agent and a reducing agent and a photosensitizer in combination (Patent Document 7). In the present invention, riboflavin or a riboflavin derivative is not used as a photopolymerization initiator but is used as a photosensitizer. By using an oxidizing agent and a reducing agent in combination with these photosensitizers, it is possible to produce polyacrylamide gels for electrophoresis in a short time and with high quality.
International Publication 2009-025135

  However, the technique described in Patent Document 7 is a technique optimized for the production of a water-insoluble gel such as a polyacrylamide gel for electrophoresis. When this technology is applied to the production of industrial water-soluble polymers, the redox reaction caused by the combined use of an oxidizing agent and a reducing agent occurs explosively, and the polymerization reaction cannot be controlled to obtain a polymer with the desired molecular weight. I can't. Further, most of the oxidizing agent and the reducing agent are consumed at the initial stage of the polymerization reaction, and the amount of residual monomer in the resulting polymer cannot be reduced.

The object of the present invention is to complete a method that can be polymerized with a light source that has a small amount of light in the ultraviolet region and is highly safe in the work environment, as a photopolymerization method applicable to the production of industrial water-soluble polymers. It is to provide a water-soluble polymer and a method for producing the same by utilizing it.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors have made water-soluble monomers having at least one vinyl group, organic dyes having an absorption band in the visible region, and peroxides essential. It has been found that a polymer having a reduced amount of residual monomer can be obtained in a short time by irradiating a solution composed of an aqueous medium containing visible light with a light source having a small amount of light in the ultraviolet region. Completed.

  By using the present invention, it was possible to produce a water-soluble polymer by a photopolymerization method using a light source that has a small amount of light in the ultraviolet region and is highly safe in the work environment. Further, the present invention has a feature that a polymer having a reduced amount of residual monomer can be obtained in a short time.

The invention is further described below.

  In the water-soluble polymer of the present invention, an organic dye and a peroxide are dissolved in an aqueous monomer solution in an aqueous monomer solution, and then the solution is irradiated with visible light to initiate polymerization. At this time, the pH of the solution is appropriately adjusted. The water-soluble monomer having a vinyl group used in the polymerization is a nonionic monomer, a cationic monomer, an anionic monomer, or a polyfunctional monomer having a plurality of vinyl groups. One or more water-soluble monomers may be used. Polymers that can be polymerized using these monomers are nonionic water-soluble polymers, cationic water-soluble polymers, anionic water-soluble polymers, and amphoteric water-soluble polymers. In addition, a crosslinkable water-soluble polymer obtained by polymerizing a polyfunctional monomer having a plurality of vinyl groups can also be produced.

Examples of nonionic monomers include (meth) acrylamide, dimethylacrylamide, diethylacrylamide, isopropylacrylamide, hydroxyethylacrylamide, vinylpyrrolidone, vinylformamide, vinylacetamide, and the like. A plurality of these nonionic water-soluble monomers can be used in combination, and it is preferable that acrylamide is included because of the ease of the polymerization reaction.

Among the cationic monomers, examples of tertiary amino group-containing cationic monomers include dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylamide, and diethylaminopropyl. Examples include (meth) acrylamide and salts thereof. Examples of quaternary ammonium base-containing cationic monomers include (meth) acryloyloxyethyltrimethylammonium chloride, (meth) acryloyloxyethyldimethylbenzylammonium chloride, (meth) acryloylaminopropyltrimethylammonium chloride, (meth) acryloyl. Examples include aminopropyldimethylbenzylammonium chloride and (meth) acryloyloxy 2-hydroxypropyltrimethylammonium chloride. Examples thereof include allylamine, diallylmethylamine and salts thereof, diallyldimethylammonium chloride and the like. It is also possible to use a combination of a plurality of these cationic water-soluble monomers.

Examples of the anionic monomer include (meth) acrylic acid, itaconic acid, 2-acrylamido 2-methylpropane sulfonic acid, vinyl sulfonic acid, allyl sulfonic acid, styrene sulfonic acid, and salts thereof. It is also possible to use a combination of a plurality of these anionic water-soluble monomers.

Examples of polyfunctional monomers having a plurality of vinyl groups include methylene bisacrylamide, methylene bismethacrylamide, divinylbenzene, N, N-diallylamine, N, N-diallylamine hydrochloride, N, N, N-tri Allylamine, N, N, N-triallylamine hydrohalide, N-methyl-N, N, N-triammonium halide, N-methyl-N, N, N-triallylammonium halide, N, N, N, N- Examples thereof include tetraallyl ammonium halide, diallyl fumarate, diallyl maleate and the like. It is also possible to use a combination of a plurality of these polyfunctional monomers.

  The total concentration of the water-soluble monomer having a vinyl group is desirably in the range of 5% by mass to 90% by mass, and more preferably in the range of 20% by mass to 60% by mass as the productivity increases.

  Examples of organic dyes include riboflavin, folic acid, methylene blue, eosin Y, dibromofluorescein, rhodamine B, pyrogallol, dichlorofluorescein, erythrosine B, fluorescin, uranin, rhodamine 123, fluoresceinamine I, fluoresceinamine II, rose bengal, modern blue 29, Eriochrome cyanine R, naphthochrome green, aurintricarboxylic acid, coumarin 343, proflavine, mercurochrome, methyl red, methyl orange, methyl yellow, bromocresol purple, bromophenol blue, free base porphyrin, free base phthalocyanine, chlorin, Examples include bacteriochlorophyll and derivatives thereof, but water or an aqueous medium particularly in the range of pH 3 to 10. Organic dye which is soluble in the preferred. Among these, riboflavin or riboflavin derivatives are preferable, and sodium riboflavin-5'-phosphate having high solubility in water is most preferable. The addition amount of the organic dye is in the range of 1 ppm to 500 ppm, more preferably in the range of 5 ppm to 100 ppm with respect to the monomer concentration. When the amount of the organic dye added is too small, the polymerization reaction hardly proceeds. When the amount of the organic dye added is too large, all of the light is absorbed near the surface and the polymerization reaction is caused by disproportionation between excited species. May not start.

  In the present invention, for the purpose of promoting the polymerization reaction, it is necessary to contain a peroxide together with the organic dye. Examples of peroxides include ammonium persulfate, potassium persulfate, sodium persulfate, hydrogen peroxide, benzoyl peroxide, and ammonium persulfate and sodium persulfate are desirable from the viewpoint of solubility. The amount of peroxide added is in the range of 10 to 50,000 ppm, more preferably in the range of 500 to 20,000 ppm with respect to the monomer concentration.

  In addition to the above raw materials, additives such as a chain transfer agent may be used as necessary for adjusting the molecular weight. Examples of chain transfer agents can be selected from commonly used compounds having chain transfer properties such as isopropyl alcohol, mercaptoethanol, sodium gluconate, sodium formate, and sodium hypophosphite. .

  As a light source of this embodiment, what mainly emits light of a visible region is preferable. Examples of the light source that can emit light having such a wavelength include fluorescent lamps, LED lamps, metal halide lamps, xenon lamps, mercury lamps, and the like. preferable. In the case of fluorescent lamps and LED lamps, there are blue, bluish white, green, pink lamps, and the like, and therefore, it is possible to select and use a lamp suitable for the absorption region of the organic dye to be used. These light sources may be used alone or in combination.

The illuminance of visible light to be irradiated is preferably 100 to 500,000 lx. When the illuminance is less than this, polymerization may not proceed sufficiently, and when it is too strong, reaction control becomes difficult and dangerous. A more preferable range is 1,000 to 150,000 lx.

  Although this embodiment is performed in a dissolved state in an aqueous medium, a medium in which a water-soluble organic solvent such as alcohol is mixed as an aqueous medium can be used if necessary for the reaction. The organic dye and peroxide are each dissolved in advance in an aqueous medium. The solution and the water-soluble monomer are mixed under light shielding to obtain a reaction solution.

In this embodiment, it is desirable to perform the reaction solution in the range of pH 2 to 10. The pH can be adjusted using a suitable pH adjusting solution such as dilute hydrochloric acid, dilute sulfuric acid, sodium hydroxide aqueous solution or the like as necessary.

  In the polymerization method of the present invention, the polymerization can be carried out even in an atmosphere containing oxygen such as air, but if necessary, the reaction solution or the polymerization reaction field is oxygenated with an inert gas such as nitrogen or argon. Polymerization can also be performed in the substituted state.

  The shape of the polymerization vessel is not particularly limited as long as the reaction solution can be irradiated with visible light. Among them, it is preferable to use a container having a flat bottom and a large surface area because quality control of the obtained product is easy. When a container having a flat bottom and a large surface area is used, the reaction solution can be kept thin and flat, so that visible light irradiation can be performed uniformly.

  The temperature at the start of visible light irradiation is preferably in the range of 5 to 60 ° C. If the temperature is lower than this, it takes a long time to start the reaction, and if the temperature is too high, heat may be generated during polymerization and bumping may occur, which is dangerous.

  The visible light irradiation time for photopolymerization is preferably 10 to 120 minutes. If it is less than this, the reaction does not proceed sufficiently, and if it is more than this, a side reaction may occur.

(Example)
EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not restrict | limited to a following example, unless the summary is exceeded.

A 50 mass% acrylamide aqueous solution 506.14 g, a 65 mass% diallyldimethylammonium chloride aqueous solution 379.9 g, and pure water 88.97 g were mixed, and the pH was adjusted to 5 with dilute sulfuric acid. To the mixed solution, 12.5 g of a 0.2% by mass riboflavin-5′-phosphate sodium phosphate aqueous solution and 12.5 g of a 10% by mass ammonium persulfate aqueous solution were added under light shielding, while replacing the dissolved oxygen with nitrogen gas. The temperature was adjusted to 25 ° C. The whole amount of the aqueous solution was supplied to a stainless steel container (408 mm × 290 mm) coated with a polyvinylidene chloride resin, and the upper part was covered with one polyvinylidene chloride film. A 20 W fluorescent lamp (FL20SS-EDC / 18PDL manufactured by Toshiba) was installed above this, and the illuminance was adjusted to 20,000 lx. The temperature of the aqueous solution immediately increased after the start of visible light irradiation, and reached the peak temperature after 5 minutes. The polymer obtained by irradiation with visible light for 30 minutes was in the form of a transparent and elastic hydrous gel. The obtained hydrogel was cut into small pieces with scissors and then dissolved with pure water to a concentration of 1% by mass, and the viscosity at 25 ° C. (B type viscometer, rotor rotation speed 30 rpm) was measured. The residual acrylamide concentration was measured by liquid chromatography after removing the polymer component. Table 1 shows the viscosity at 1% by mass and the residual acrylamide concentration.

A 50 mass% acrylamide aqueous solution 303.68 g, a 65 mass% diallyldimethylammonium chloride aqueous solution 227.94 g, and pure water 453.38 g were mixed, and the pH was adjusted to 5 with dilute sulfuric acid. To the mixed solution, 7.5 g of 0.2 mass% sodium riboflavin-5′-phosphate ester aqueous solution and 7.5 g of 10 mass% ammonium persulfate aqueous solution were added under light shielding, and the dissolved oxygen was replaced with nitrogen gas. The temperature was adjusted to 25 ° C. The whole amount of the aqueous solution was supplied to a stainless steel container (408 mm × 290 mm) coated with a polyvinylidene chloride resin, and the upper part was covered with one polyvinylidene chloride film. A 20 W fluorescent lamp was installed above this, and the illuminance was adjusted to 20,000 lx. The temperature of the aqueous solution immediately increased after the start of visible light irradiation, and reached the peak temperature after 11 minutes. The polymer obtained by irradiation with visible light for 30 minutes was in the form of a transparent and elastic hydrous gel. The obtained hydrogel was cut into small pieces with scissors and then dissolved with pure water to a concentration of 1% by mass, and the viscosity at 25 ° C. (B type viscometer, rotor rotation speed 30 rpm) was measured. The residual acrylamide concentration was measured by liquid chromatography after removing the polymer component. Table 1 shows the viscosity at 1% by mass and the residual acrylamide concentration.

300.0 g of a 50% by mass acrylamide aqueous solution and 692.5 g of pure water were mixed, and the pH was adjusted to 5 with dilute sulfuric acid. To the mixed solution, 3.75 g of 0.2 mass% aqueous sodium riboflavin-5′-phosphate ester solution and 3.75 g of 10 mass% aqueous ammonium persulfate were added under light shielding, and the dissolved oxygen was replaced with nitrogen gas. The temperature was adjusted to 25 ° C. The whole amount of the aqueous solution was supplied to a stainless steel container (408 mm × 290 mm) coated with a polyvinylidene chloride resin, and the upper part was covered with one polyvinylidene chloride film. A 20 W fluorescent lamp was installed above this, and the illuminance was adjusted to 20,000 lx. The temperature of the aqueous solution immediately increased after the start of visible light irradiation, and reached the peak temperature after 6 minutes. The polymer obtained by irradiation with visible light for 30 minutes was in the form of a transparent and elastic hydrous gel. The obtained hydrogel was cut into small pieces with scissors and then dissolved with pure water to a concentration of 1% by mass, and the viscosity at 25 ° C. (B type viscometer, rotor rotation speed 30 rpm) was measured. The residual acrylamide concentration was measured by liquid chromatography after removing the polymer component. Table 1 shows the viscosity at 1% by mass and the residual acrylamide concentration.

  Polymerization was carried out in the same manner as in Example 1 except that 12.5 g of a 10% by mass sodium persulfate aqueous solution was added instead of the 10% by mass ammonium persulfate aqueous solution in Example 1. The temperature of the aqueous solution immediately increased after the start of visible light irradiation, and reached the peak temperature after 8 minutes. The polymer obtained by irradiation with visible light for 30 minutes was in the form of a transparent and elastic hydrous gel. The obtained hydrogel was cut into small pieces with scissors and then dissolved with pure water to a concentration of 1% by mass, and the viscosity at 25 ° C. (B type viscometer, rotor rotation speed 30 rpm) was measured. The residual acrylamide concentration was measured by liquid chromatography after removing the polymer component. Table 1 shows the viscosity at 1% by mass and the residual acrylamide concentration.

Polymerization was carried out in the same manner as in Example 1 except that 12.5 g of 10% by mass hydrogen peroxide was added instead of the 10% by mass ammonium persulfate aqueous solution of Example 1. The temperature of the aqueous solution immediately increased after the start of visible light irradiation, and reached the peak temperature after 18 minutes. The polymer obtained by irradiation with visible light for 30 minutes was in the form of a transparent and elastic hydrous gel. The obtained hydrogel was cut into small pieces with scissors and then dissolved with pure water to a concentration of 1% by mass, and the viscosity at 25 ° C. (B type viscometer, rotor rotation speed 30 rpm) was measured. The residual acrylamide concentration was measured by liquid chromatography after removing the polymer component. Table 1 shows the viscosity at 1% by mass and the residual acrylamide concentration.

  Polymerization was carried out in the same manner as in Example 1 except that the fluorescent lamp of Example 1 was replaced with an LED lamp (LDL20T · N / 13/12 manufactured by Toshiba Corporation). The temperature of the aqueous solution immediately increased after the start of visible light irradiation, and reached the peak temperature after 7 minutes. The polymer obtained by irradiation with visible light for 30 minutes was in the form of a transparent and elastic hydrous gel. The obtained hydrogel was cut into small pieces with scissors and then dissolved with pure water to a concentration of 1% by mass, and the viscosity at 25 ° C. (B type viscometer, rotor rotation speed 30 rpm) was measured. The residual acrylamide concentration was measured by liquid chromatography after removing the polymer component. Table 1 shows the viscosity at 1% by mass and the residual acrylamide concentration.

  Polymerization was carried out in the same manner as in Example 1 except that the 0.2% by mass riboflavin-5'-phosphate sodium salt aqueous solution of Example 1 was replaced with a 0.2% by mass Rose Bengal aqueous solution. The temperature of the aqueous solution immediately increased after the start of visible light irradiation, and reached the peak temperature after 12 minutes. The polymer obtained by irradiation with visible light for 30 minutes was in the form of a transparent and elastic hydrous gel. The obtained hydrogel was cut into small pieces with scissors and then dissolved with pure water to a concentration of 1% by mass, and the viscosity at 25 ° C. (B type viscometer, rotor rotation speed 30 rpm) was measured. The residual acrylamide concentration was measured by liquid chromatography after removing the polymer component. Table 1 shows the viscosity at 1% by mass and the residual acrylamide concentration.

Polymerization was carried out in the same manner as in Example 1 except that the monomer composition and monomer concentration in Example 1 were changed as shown in Table 1. In Examples 12 and 13, polymerization was carried out with sodium hydroxide adjusted to pH 8.5. The polymer obtained by irradiation with visible light for 30 minutes was a transparent and elastic hydrous gel in all Examples. The obtained hydrogel was cut into small pieces with scissors and then dissolved with pure water to a concentration of 1% by mass, and the viscosity at 25 ° C. (B type viscometer, rotor rotation speed 30 rpm) was measured. The residual acrylamide concentration was measured by liquid chromatography after removing the polymer component. Table 1 shows the viscosity at 1% by mass and the residual acrylamide concentration.

(Table 1)

AAm: acrylamide, DADMAC: diallyldimethylammonium chloride, MMCQ: methacryloyloxyethyltrimethylammonium chloride, AMCQ: acryloyloxyethyltrimethylammonium chloride ABCQ: acryloyloxyethyldimethylbenzylammonium chloride AA: acrylic acid, AMPS: 2-acrylamide 2-methyl Propanesulfonic acid, Rf: Riboflavin-5′-phosphate ester sodium Rb: Rose Bengal, APS: Ammonium persulfate, NPS: Sodium persulfate, H ₂ O ₂ : Hydrogen peroxide,

(Comparative Example 1)
Polymerization was carried out in the same manner as in Example 1 except that ammonium persulfate of Example 1 was not added. Even when visible light irradiation was started, the temperature was hardly increased and visible light irradiation was performed for 30 minutes, but the polymerization reaction hardly proceeded. The results are shown in Table 2.

(Comparative Example 2)
Polymerization was carried out in the same manner as in Example 1 except that riboflavin-5′-phosphate sodium salt of Example 1 was not added. Even when visible light irradiation was started, the temperature was hardly increased and visible light irradiation was performed for 30 minutes, but the polymerization reaction hardly proceeded. The results are shown in Table 2.

(Table 2)

(Comparative Example 3)
The sodium riboflavin-5′-phosphate ester and ammonium persulfate of Example 1 were not added, and instead, as a photopolymerization initiator, VA-086 (2,2′-azobis [N- (2) manufactured by Wako Pure Chemical Industries, Ltd. -Hydroxyethyl) -2-methylpropanamide]) Polymerization was carried out in the same manner as in Example 1 except that 12.5 g of a 10% by mass aqueous solution was added. Even when visible light irradiation was started, the temperature was hardly increased and visible light irradiation was performed for 30 minutes, but the polymerization reaction hardly proceeded. The results are shown in Table 3.

(Comparative Example 4)
It implemented except having added 12.5g of 10 mass% aqueous solution of VA-086 (2,2'-azobis [N- (2-hydroxyethyl) -2-methylpropanamide]) instead of ammonium persulfate of Example 1. Polymerization was carried out in the same manner as in Example 1. Even when visible light irradiation was started, the temperature was hardly increased and visible light irradiation was performed for 30 minutes, but the polymerization reaction hardly proceeded. The results are shown in Table 3.

(Table 3)
VA-086 2,2′-azobis [N- (2-hydroxyethyl) -2-methylpropanamide]

  In Comparative Example 1, no peroxide was added, and in Comparative Example 2, no organic dye was added. Therefore, the polymerization reaction did not occur, and there was almost no change in the reaction solution. In Comparative Example 3, a photopolymerization initiator was added, but no polymerization reaction occurred because a light source having a small ultraviolet region was used. Further, as in Comparative Example 4, the polymerization reaction did not occur even when the organic dye and the photopolymerization initiator were used in combination.

  On the other hand, in Example 1, since an organic dye and a peroxide are used in combination, the polymerization reaction that did not occur in Comparative Example 1 and Comparative Example 2 starts immediately, and a polymer with a high polymerization rate is obtained in a short time. I was able to. In Example 2 and Example 3, the monomer concentration was reduced, in Examples 4 and 5, sodium persulfate and hydrogen peroxide were used as the peroxide, and in Example 6, an LED lamp was used as the light source. In Example 7, rose bengal was used as the organic dye, but in any example, a polymer having a high polymerization rate could be obtained as in Example 1. Although the monomer composition was changed in Examples 8 to 13, a polymer having a high polymerization rate could be obtained in any Example.

  From these results, it can be seen that by using the polymerization method of the present invention, a polymer having a reduced amount of residual monomer can be obtained in a short time even when a light source having a small amount of light in the ultraviolet region is used.

By utilizing the present invention, it is possible to perform photopolymerization using a light source having as little light as possible in the ultraviolet region and a photosensitizer having an absorption band in the visible region, which is highly safe in the work environment. Furthermore, since the polymerization reaction of the polymer composition can be carried out in a short time and at a high concentration, and the polymer composition can be obtained with high production efficiency, it is considered that adaptation to the industry is extremely effective.

Claims (2)

An aqueous medium containing (meth) acrylamide and diallyldimethylammonium chloride , an organic dye and a peroxide as water-soluble monomers having one or more vinyl groups as essential components, It is produced by irradiating a solution having a water-soluble monomer concentration of 30% by mass to 90% by mass with visible light using at least one light source selected from a fluorescent lamp and an LED lamp. Manufacturing method of coalescence. The method for producing a water-soluble polymer according to claim 1, wherein the organic dye is soluble at a pH of 3 to 10 in the aqueous medium.