JP2003041141A - Water-soluble polymer dispersion and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stable water-soluble polymer dispersion by a dispersion polymerization method in the coexistence of a polymer-dispersing agent in a salt aqueous solution, to develop a dispersing agent capable of especially suppressing the increase of viscosity on polymerization, and further to provide a method for efficiently producing the polymer dispersion. SOLUTION: This water-soluble polymer dispersion contains anionic and/or nonionic water-soluble polymer fine particles having a particle diameter of <=100 μm and one or more synthetic polymers and one or more natural polymers soluble in a salt aqueous solution as dispersing agents, in the salt aqueous solution. The water-soluble polymer fine particles are produced by stirring, dispersing and polymerizing a monomer (mixture) comprising 0 to 100 mol.% of a monomer represented by the general formula (1) [R1 is H, methyl or carboxymethyl; A is SO3 , C6 H4 SO3 , CONHC(CH3 )2CH2 SO3 , C6 H4 COO or COO; R2 is H or COOY2 ; Y1 and Y2 are each H or a cation], 0 to 100 mol.% of (meth)acrylamide and 0 to 30 mol.% of a copolymerizable nonionic monomer in the salt aqueous solution.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a water-soluble polymer dispersion and a method for producing the same, and more specifically to an anionic and / or nonionic water-soluble polymer having a particle size of 100 μm or less in an aqueous salt solution. The present invention relates to a water-soluble polymer dispersion liquid in which at least one of fine particles, a synthetic polymer and a natural polymer having a specific structure, which are soluble in the aqueous salt solution as a dispersant, coexist, and their production. Regarding the method.

[0002]

2. Description of the Related Art Anionic water-soluble polymers have been applied as a flocculant for various purposes. For example, it is used as a general water treatment agent for solid-liquid separation in wastewater, and is also used as a retention aid in the sludge dewatering and paper industry in combination with a cationic flocculant. In civil engineering, it is also used as a soil solidifying agent. The following polymerization methods are conventionally known as methods for producing these anionic polymers. For example, the aqueous solution polymerization method is supplied as a paste product, and the water-in-oil emulsion polymerized product is supplied in the form of a latex after the polymerization by adding a hydrophilic emulsifier called a phase inversion agent. The legal method is often applied to produce a powder product, and a method of directly polymerizing an aqueous solution of 30 to 50% by weight of a monomer, granulating a gel polymer with a meat chopper or the like, and then directly drying. Has also been applied to the manufacture of powder products. More recently, a monomer was dissolved in a polyethylene glycol aqueous solution and polymerized,
Although a method of producing a polymer dispersion in a polymer has been carried out, a high molecular weight compound having practical performance as a flocculant has not been synthesized yet. Furthermore, it should be noted that attempts have been made to develop a method for synthesizing a cationic / amphoteric flocculant in an aqueous salt solution and to synthesize a polymerized product of an anionic polymer with a flocculant grade.

It is more difficult to synthesize an anionic polymer having a high degree of polymerization than a cationic polymer having a high degree of polymerization in an aqueous salt solution by a dispersion polymerization method. To obtain a stable dispersion. In the case of a cationic monomer, a polymer insoluble in salt water can be easily synthesized by synthesizing a monomer into which a hydrophobic group such as a benzyl group or a long-chain alkyl group has been introduced. It will be usable. In the case of anionic monomers, it is difficult to introduce a hydrophobic group into the molecule itself, so a method of copolymerizing hydrophobic monomers can be considered. In many cases, you cannot get a high one. Another factor is that the molecular weight of acrylic acid, which is mainly used as a raw material, is smaller than the molecular weight of the cationic monomer, and the calorific value per weight concentration of the solution is very large. Therefore, it is difficult to control the polymerization reaction, and the reaction product is agglomerated during the polymerization, and a stable dispersion cannot be synthesized. Alternatively, a large calorific value means that the control of the polymerization temperature is not easy and the temperature of the polymerization system is out of the control range, and the degree of polymerization of the anionic water-soluble polymer produced is lowered. . At present, the method of precipitating the generated anionic water-soluble polymer in salt water is being solved by combining various salts, and the stabilization of the dispersion liquid can be achieved by varying the composition of the ionic polymer dispersant. It became possible by examining the molecular weight and coexisting.

A dispersant is an important point in efficiently polymerizing a water-soluble polymer dispersion in an aqueous salt solution and improving the stability of the resulting dispersion. To date, ionic or nonionic polymers have been investigated as synthetic polymers. However, a dispersant system combining a synthetic polymer and a natural polymer has not been studied. Focusing on manufacturing problems, there is still room for improvement such as prevention of thickening of the polymer during manufacturing or stability after manufacturing.

[0005]

The object of the present invention is to develop a stable water-soluble polymer dispersion by a dispersion polymerization method in the presence of a polymer dispersant in an aqueous salt solution, and particularly to increase the amount during polymerization. The aim is to develop a dispersant that suppresses viscosity. Still another object is to develop a method for efficiently producing a dispersion liquid.

[0006]

In order to solve the above problems, the present inventors have conducted a detailed study and as a result, by combining specific polymer substances, a stable water-soluble polymer dispersion liquid was obtained. The inventors have found that the obtained dispersion can be produced efficiently and stably, and completed the present invention. That is, the invention of claim 1 of the present invention is that anionic and / or nonionic water-soluble polymer fine particles having a particle size of 100 μm or less in a salt aqueous solution, and a synthetic polymer soluble in the salt aqueous solution as a dispersant. And a water-soluble polymer dispersion in which at least one of natural polymers coexists.

According to a second aspect of the present invention, the anionic and / or nonionic water-soluble polymer comprises 0 to 100 mol% of a monomer represented by the following general formula (1) and 0 to (meth) acrylamide.
Of 100 to 100 mol% and 0 to 30 mol% of another copolymerizable nonionic monomer in a salt solution under stirring with dispersion polymerization. The water-soluble polymer dispersion according to claim 1.

[Chemical 1] General formula (1) R1 is hydrogen, a methyl group or a carboxymethyl group, A is SO3, C6H4SO3, CONHC (CH3) 2CH
2SO3, C6H4COO or COO, R2 is hydrogen or COOY2, Y1 or Y2 is hydrogen or cation

According to a third aspect of the present invention, the synthetic polymer is
The water-soluble polymer dispersion according to claim 1, which is selected from polymers having one or more structural units represented by the following general formula (2) or (3).

[Chemical 2] General formula (2) Here, R3 is hydrogen or a methyl group, X is CN, CONR
5R6 (R5 and R6 are hydrogen, an alkyl group having 1 to 4 carbon atoms or an alkoxyl group), OR7 (R7 is hydrogen or an alkyl group having 1 to 4 carbon atoms or an alkoxyl group, an acyl group), NHCOR8 (R8 is hydrogen, An alkyl group or an alkoxyl group having 1 to 4 carbon atoms), and 1 to 10 carbon atoms
, An alkyl group, an alkoxyl group, an aryl group, a nonionic hetero 5-membered ring or a 6-membered ring, and R4 represents hydrogen or an alkyl group having a prime number of 1 to 3, respectively.

[Chemical 3] General formula (3) R5 is hydrogen, a methyl group or a carboxymethyl group, A is SO3, C6H4SO3, CONHC (CH3) 2CH
2SO3, C6H4COO or COO, R6 represents hydrogen or COOY4, Y3 or Y4 represents hydrogen or cation, respectively.

According to a fourth aspect of the invention, the synthetic polymer is anionic and has an ion equivalent value of 1.0 to 11 meq.
It is / g, It is a water-soluble polymer dispersion liquid of Claim 3 characterized by the above-mentioned.

According to a fifth aspect of the present invention, the natural polymer is
The water-soluble polymer according to claim 1, which is one or more selected from starch, starch derivative, cellulose derivative, alginate, pectin, acacia gum, locust bean gum, and guar gum. It is a dispersion liquid.

The invention of claim 6 is characterized in that the natural polymer is anionic and has an ion equivalent value of 1.0 to 7.0. It is a liquid.

The invention of claim 7 is characterized in that the anionic and / or nonionic water-soluble polymer constituting the polymer dispersion has a weight average molecular weight of 2,000,000 or more and 20,000,000 or less. Item 1. The water-soluble polymer dispersion according to Item 1.

The invention according to claim 8 is the water-soluble polymer dispersion according to claim 1, characterized in that the salt constituting the aqueous salt solution contains at least one polyvalent anion salt.

According to a ninth aspect of the present invention, in a salt aqueous solution, at least one or more of a synthetic polymer and a natural polymer which are soluble in the salt aqueous solution are allowed to coexist as a dispersant, and the general formula (1) ) Monomers represented by) 0 to 100 mol% and (meth)
A particle size of 1, characterized in that a monomer (mixture) consisting of 0 to 100 mol% of acrylamide and 0 to 30 mol% of another copolymerizable nonionic monomer is dispersed and polymerized under stirring.
It is a method for producing a water-soluble polymer dispersion liquid comprising fine particles of 00 μm or less.

The invention of claim 10 is characterized in that the synthetic polymer is selected from polymers having one or more structural units represented by the general formula (2) or (3). Item 10. A method for producing a water-soluble polymer dispersion according to Item 9.

According to the invention of claim 11, the synthetic polymer is anionic and has an ion equivalent value of 1.0 to 11 me.
It is q / g, It is a manufacturing method of the water-soluble polymer dispersion liquid of Claim 10 characterized by the above-mentioned.

In a twelfth aspect of the present invention, the natural polymer is starch, starch derivative, cellulose derivative, alginate, pectin, gum arabic, locust beer.
10. The method for producing a water-soluble polymer dispersion according to claim 9, wherein the method comprises at least one selected from the group consisting of guar gum and guar gum.

According to a thirteenth aspect of the present invention, the natural polymer is anionic, and the ion equivalent value is 1.0 to 7.0. The water-soluble polymer dispersion according to the twelfth aspect. It is a method for producing a liquid.

The invention according to claim 14 is the method for producing a water-soluble polymer dispersion according to claim 9, characterized in that the salt constituting the aqueous salt solution contains at least one polyvalent anion salt. .

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION A water-soluble monomer prepared by a dispersion polymerization method in which a water-soluble monomer or a mixture of water-soluble monomers is allowed to coexist with an ionic polymer dispersant capable of being added to the salt aqueous solution. A method for producing a dispersion liquid composed of molecules is described in JP-B-4-
It can be manufactured by the method described in Japanese Patent No. 39481, Japanese Patent Publication No. 3-74682, or Japanese Patent Publication No. 6-72170. The first publication discloses a method in which a polyvalent alcohol coexists as a dispersant during polymerization, and the second publication discloses a method in which a cationic polymer soluble in a polyvalent anion salt aqueous solution is polymerized as a dispersant. A method of coexisting is disclosed. Further, the third publication discloses a method in which a soluble anionic polymer is allowed to coexist in a polyvalent anion salt aqueous solution as a dispersant during polymerization.

The manufacturing method will be specifically described below. Sulfonic acid group-containing monomer, carboxyl group-containing monomer, (meth) acrylamide and other copolymerizable monomer, which are anionic monomers used as raw materials, are each added to a salt aqueous solution. Dissolve, 5-40 of all anionic monomers
The mol% is neutralized with an alkaline substance. Then, a synthetic polymer and a natural polymer, which are soluble in an aqueous salt solution, are added as a dispersant, nitrogen substitution is performed, polymerization is initiated by a radical polymerization initiator, and polymerization is performed with stirring.

For the dispersant of the present invention, one or more kinds of synthetic polymer and natural polymer are selected and used in combination. First, a synthetic polymer will be described. Either a nonionic polymer or an anionic polymer can be used, but an anionic polymer is more preferable. Examples of the anionic polymer include (co) polymers of (meth) acrylic acid, maleic acid, itaconic acid, acrylamido 2-methylpropanesulfonic acid (salt) and styrenesulfonic acid (salt). It is united. In addition, nonionic monomers such as acrylamide, N-vinylformamide, N-
Vinylacetamide, N-vinylpyrrolidone, N, N-
A copolymer with dimethylacrylamide, acrylonitrile, diacetone acrylamide, 2-hydroxyethyl (meth) acrylate, etc. can also be used. In addition, anion-modified polyvinyl alcohol, styrene / maleic anhydride copolymer, butene / maleic anhydride copolymer, or their partially amidated products. The most preferred combination is (meth) acrylic acid and 2-acrylamido-2-methylpropanesulfonic acid. Examples of the nonionic polymer include (co) the above-mentioned nonionic monomers.
It is a completely amidated product such as a polymer, polyvinyl alcohol, a styrene / maleic anhydride copolymer or a butene / maleic anhydride copolymer.

On the other hand, as the natural polymer, one or more selected from starch, starch derivative, cellulose derivative, alginate and pectin is used. Both anionic and nonionic properties can be used, but anionic properties are preferred. As the anionic polymer, oxidized starch,
Carboxymethylated starch, phosphorylated starch, carboxymethyl cellulose, sodium alginate,
Examples include pectin and gum arabic. Examples of the nonionic polymer include raw starch, enzyme-modified starch, hydroxyethyl cellulose, methyl cellulose, guar gum, locust bean gum and the like. Further, ionic polymers such as carboxymethylated starch, phosphorylated starch, carboxymethyl cellulose, sodium alginate, pectin, and gum arabic are more preferable.

The compounding ratio of these synthetic polymer and natural polymer is 8: 1 to 1: 8, preferably 5: 1 to 1: 5, and is appropriately selected according to the monomer to be polymerized. In particular, when carrying out the copolymerization in which the ratio of the anionic monomer is low, it is effective to increase the ratio of the synthetic polymer having high ionicity.
On the contrary, when the copolymerization ratio of the ionic monomer is low, it is effective to increase the ratio of the natural polymer. The dispersant of the present invention, whether natural or synthetic, is not limited to being used in two or more types, but it is very complicated in terms of management to combine with two, three, or four types, and the natural type is preferably used. It is more efficient and more effective to select an optimal blending ratio for each system or synthetic system.

The molecular weight of these natural or synthetic polymer dispersants is 5,000 to 3,000,000, preferably 50,000 to 2,000,000. The molecular weight of the nonionic synthetic polymer dispersant is 1,000 to 1,000,000, and preferably 1,000 to 500,000. The amount of the natural or synthetic polymer dispersant added to the monomer is 1/100 of the total amount of both dispersants with respect to the monomer.
˜15 / 100, preferably 2/100 to 1/1
It is 0.

The reason why the dispersant of the present invention becomes very effective by combining a natural system and a synthetic system cannot be elucidated in many theoretical parts. However, when estimated from the viewpoint of phenomena, it becomes as follows. That is, as the polymerization proceeds in a salt aqueous solution, the concentration of the produced polymer becomes equal to or higher than the solubility and precipitation of polymer particles begins, but before that, the polymer itself (polymerization system) is not formed because the polymer is dissolved. The viscosity also increases, and the dissolved polymer and precipitated particles coexist. After that, the ratio of the precipitated polymer increases, the viscosity of the polymer gradually decreases, and the polymer changes into a dispersed state. In this coexistence state, the slip between the precipitated particles and the gelled dissolved polymer is improved, and the phase change from the thickened state before the phase change to the dispersed state is smoothly transferred. It is considered to be the main role of the agent. The anionic group ionizes the surface of the particles and prevents the particles from coagulating. On the other hand, the natural polymer tends to be incompatible with the synthetic polymer in which the polymerization is progressing. In addition, it has low ionicity and is relatively hydrophobic, and surrounds the deposited particles adsorbed by a hydrophobic bond and causes microscopic phase separation between the deposited particles and the dissolved gelled polymer. It is presumed that this effect lowers the viscosity around the particles, improves the slip between the precipitated particles and the dissolved gelled polymer, and achieves a smooth phase change.

The temperature during the polymerization is 5 to 40 ° C, preferably 15 to 30 ° C. If the temperature is higher than 40 ° C., it is difficult to control the polymerization, and a rapid temperature rise or agglomeration of the polymerization liquid occurs, so that a stable dispersion liquid having a high polymerization degree is not formed.

The starting point for use is 2,2-azobis [2-
(5-Methyl-2-imidazolin-2-yl) propane] dihydrochloride, or 4,4-azobis (4-
An azo-based polymerization initiator such as methoxy-2,4dimethyl) valeronitrile can also be used, but it is difficult to start unless the addition amount is increased. Therefore, if the temperature of the polymerization system rises to some extent, the polymerization rate is accelerated and it is difficult to control. Therefore, a redox initiator that can be started at a low temperature with a small amount added is used. The amount of the initiator added is 10 to 50 ppm, preferably 10 to 30 pp, per monomer at the start of polymerization.
m is added. Usually, when the monomer concentration is low, the polymerization does not start at this initiator addition amount and temperature. However, in the present invention, the dispersion polymerization method in an aqueous salt solution is used, so that the monomer concentration is 20 to 35% by weight, and it is presumed that the monomer concentration is relatively high and the process is started. However, since the addition amount level is low, the polymerization rate becomes low when added once. Therefore, it is preferable to add it several times. The number of additions is 2-5
Times, preferably 2-3 times.

As the redox type initiator, an oxidizing substance and a reducing substance are combined. Examples of oxidizing substances are ammonium peroxodisulfate, potassium peroxodisulfate, hydrogen peroxide and the like, and examples of reducing substances are sodium sulfite, sodium bisulfite, ferrous sulfate, sodium thiosulfate, oxalic acid. Sodium, triethanolamine, tetramethylethylenediamine, and the like are used, and among these, a combination of ammonium peroxodisulfate and sodium bisulfite is most preferable. In this way, by controlling the addition amount level of the initiator to be low at a relatively low temperature, it is possible to control the polymerization rate to produce a stable polymer dispersion with a high degree of polymerization. The molecular weight of the anionic water-soluble polymer produced in this manner is usually 2,000,000 or more, and depending on the conditions selected, 5 to 20,000,000 are produced, and the anionic water-soluble polymer is sufficiently durable to be used as an aggregating agent. is there.

The anionic monomer used may be a sulfone group or a carboxyl group, and both may be copolymerized. Examples of the sulfonic group-containing monomer are vinyl sulfonic acid, vinyl benzene sulfonic acid, 2-acrylamido 2-methylpropane sulfonic acid, and the like. Examples of the carboxyl group-containing monomer include methacrylic acid, acrylic acid, itaconic acid, maleic acid or p-
Carboxystyrene and the like. Further, the polymer dispersion liquid may be a copolymer with another nonionic monomer.
For example, (meth) acrylamide, N, N-dimethylacrylamide, vinyl acetate, acrylonitrile, methyl acrylate, 2-hydroxyethyl (meth) acrylate,
Diacetone acrylamide, N-vinylpyrrolidone, N
-Vinylformamide, N-vinylacetamide, acryloylmorpholine and the like can be mentioned, and copolymerization with one kind or two or more kinds thereof is possible. The most preferred combination is 2-acrylamido-2-methylpropanesulfonic acid, acrylic acid and chrylamido.

The molar ratio of the anionic monomer in the case of producing the anionic polymer dispersion is from 1 to 100 mol%, preferably from 3 to 100 mol%. Further, a copolymerizable nonionic monomer may be copolymerized. The amount is 0 to 30 mol%. When a dispersion of a nonionic polymer is prepared, acrylamide alone is used as the nonionic monomer, or 0 to 30 mol% of the copolymerizable nonionic monomer is used.

The salt to be used is a salt of an alkali metal ion such as sodium or potassium or an ammonium ion with a halide ion, a sulfate ion, a nitrate ion, a phosphate ion or the like, but a salt with a polyvalent anion. Is more preferable. The salt concentration of these salts is 7% by weight to
Can be used up to saturation concentration.

The anionic or nonionic water-soluble polymer composed of the dispersion liquid produced by the dispersion polymerization method of the present invention is produced by an aqueous solution polymerization method, a water-in-oil emulsion polymerization method, or a water-in-oil dispersion polymerization method. The apparent viscosity when dissolved in water is much lower than that of the anionic polymer.
For example, sodium acrylate and acrylamide 3
In the case of a copolymer containing a molar ratio of 0/70, the viscosity of an aqueous solution having a molecular weight of about 13,000,000 and 0.2% by weight is determined by an aqueous solution polymerization method, a water-in-oil emulsion polymerization method, a water-in-oil dispersion polymerization method. Whereas the anionic water-soluble polymer composed of the dispersion liquid produced by the dispersion polymerization method used in the present invention is 20 to 1
It is 00 mPa · s. This is also due to the influence of inorganic salts coexisting during the polymerization. Another reason is that only 5 to 40 mol% of the acid of the monomer used during the polymerization is neutralized. However, even if these effects are subtracted, this alone cannot explain. It is presumed that this phenomenon is also caused by the fact that the polymer produced in the salt aqueous solution is polymerized while precipitating, but the detailed mechanism is unclear. for that reason,
The fact that the apparent viscosity is low means that the dispersibility in water for the purpose of treatment is good and the aggregation function can be sufficiently exhibited. For example, in the case of application as a filler retention improver, the addition place closer to the papermaking machine can be selected. For example, even if it is added at a place closer to the machine such as the screen outlet, the risk of trouble due to uneven distribution can be said to be low. It is also possible to sufficiently disperse even sludge having a concentration of 15,000 to 30,000 mg / L, which causes poor dispersibility of the added coagulant, and exert its effect.

[0034]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples unless it exceeds the gist.

[0035]

Example 1 In a four-necked 500 ml separable flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube, deionized water: 77.4 g, ammonium sulfate 110.8.
g, sodium sulfate 25.6 g, 2-acrylamide 2
-Methyl propane sulfonic acid 16.6 g, 60% acrylic acid: 28.8 g, 50% acrylamide: 181.
7 g was added, and 16 mol% of the anionic monomer was neutralized with 6.8 g of 30% by weight sodium hydroxide. Also,
Acrylic acid 2-methylpropanesulfonic acid monomer aqueous solution was neutralized to 50 mol% and then polymerized anionic polymer aqueous solution (molecular weight 700,000, concentration 20% by weight) 18.
6 g (to 3% of monomer), and carboxymethylcellulose
33.1 g of a 15 wt% solution of sulfur (molecular weight: 120,000) (4% of monomer) was added. Then, while stirring, nitrogen is introduced from the nitrogen introducing pipe to remove dissolved oxygen. During this time, the internal temperature is adjusted to 25 ° C. in a constant temperature water bath. Nitrogen introduction 30
After that, 3.1 g of 0.1 wt% ammonium peroxodisulfate and 0.1 wt% aqueous solution of ammonium hydrogen sulfite were added in this order to 3.1 g (monomer, 25 pp each).
m) was added to initiate polymerization. Two hours after the start of the polymerization, the viscosity of the reaction solution was observed to increase slightly, but no further increase in the solution viscosity occurred and dispersed particles began to precipitate. Eight hours after the initiation of the polymerization, the same amount of each of the above initiators was added, and the polymerization was continued for another 12 hours to complete the reaction.
This prototype is called prototype-1. The molar ratio of 2-acrylamido-2-methylpropanesulfonic acid / acrylic acid / acrylamide of this prototype-1 was 7/13/80,
The viscosity was 290 mPa · s. As a result of microscopic observation, it was found that the particles were 3 to 20 μm. In addition, a molecular weight measuring device by static light scattering method (DL manufactured by Otsuka Electronics)
S-7000) to measure the weight average molecular weight. The results are shown in Table 3.

[0036]

Example 2 Deionized water: 57.9 g, ammonium sulfate 115.0 was placed in a 4-neck 500 ml separable flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube.
g, sodium sulfate 20.4 g, 2-acrylamide 2
-Methyl propane sulfonic acid 10.3 g, 60% acrylic acid: 23.8 g, 50% acrylamide: 200.
5 g was added and 22 mol% of the anionic monomer was neutralized with 7.3 g of 30% by weight sodium hydroxide. Further, in a monomer mixture aqueous solution consisting of methacrylic acid / acrylamido-2-methylpropanesulfonic acid = 3/7 (molar ratio), after neutralizing 90 mol% of the acid, a copolymer aqueous solution polymerized (molecular weight 1.2 million) 16.5 g (% of monomer)
And a 10% by weight solution of sodium alginate (molecular weight 2
500,000) 50.0 g (relative to monomer 4%) was added. Then, while stirring, nitrogen is introduced from the nitrogen introducing pipe to remove dissolved oxygen. During this time, the internal temperature is adjusted to 25 ° C. in a constant temperature water bath. After 30 minutes from the introduction of nitrogen, 2.5 g (relative to monomer, 20 ppm) of 0.1 wt% ammonium peroxodisulfate and 0.1 wt% aqueous solution of ammonium hydrogen sulfite were added in this order to initiate polymerization. Two hours after the start of the polymerization, the viscosity of the reaction solution was observed to increase slightly, but no further increase in the solution viscosity occurred and dispersed particles began to precipitate. After 6 hours from the start of the polymerization, the same amount of each of the above initiators was added, and the polymerization was further continued for 15 hours to complete the reaction. This prototype is called prototype-2. The molar ratio of 2-acrylamido-2-methylpropanesulfonic acid / acrylic acid / acrylamide of this prototype-2 was 3/12.
/ 85 and the viscosity was 350 mPa · s. As a result of microscopic observation, it was found that the particles were 3 to 20 μm. The results are shown in Table 3.

[0037]

Example 3 In a four-neck 500 ml separable flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube, deionized water: 79.0 g, ammonium sulfate 115.0.
g, sodium sulfate 20.4 g, 60% acrylic acid: 6
2.6 g and 50% acrylamide: 173.0 g were added, and 22 mol% of the anionic monomer was neutralized with 15.3 g of 30% by weight sodium hydroxide. After neutralizing 60 mol% of the acrylic acid monomer, 24.8 g of a polymerized aqueous solution (20% aqueous solution, molecular weight 1.5 million) (to 4% monomer) and pectin (12.5% solution, molecular weight 200)
10,000) 9.9 g (1% of monomer). Then, while stirring, nitrogen is introduced from the nitrogen introducing pipe to remove dissolved oxygen. During this time, the internal temperature is adjusted to 25 ° C. in a constant temperature water bath. After 30 minutes of introducing nitrogen, 0.1% by weight of ammonium peroxodisulfate and ammonium bisulfite of 0.1% by weight.
3.1% by weight of aqueous solution (to the monomer,
25 ppm) was added to initiate polymerization. After 1 hour and 50 minutes from the initiation of polymerization, a slight increase in the viscosity of the reaction liquid was observed, but no further increase in liquid viscosity occurred and dispersed particles began to precipitate. After 6 hours from the start of the polymerization, the same amount of each of the above initiators was added, and the polymerization was further continued for 15 hours to complete the reaction. This prototype is referred to as prototype-3. In this prototype-3, the acrylic acid / acrylamide molar ratio was 30/7.
It was 0 and the viscosity was 400 mPa * s. As a result of microscopic observation, it was found that the particles were 2 to 25 μm. The results are shown in Table 3.

[0038]

Examples 4 to 20 By the same operation as in Examples 1 to 3,
A water-soluble polymer dispersion was synthesized by combining the monomer composition shown in Table 1 with a synthetic polymer and a natural polymer. The results are shown in Table 3.

[0039]

[Comparative Example 1] Deionized water: 77.4 g, ammonium sulfate 110.8 was placed in a four-neck 500 ml separable flask equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen inlet tube.
g, sodium sulfate 25.6 g, 2-acrylamide 2
-Methyl propane sulfonic acid 16.6 g, 60% acrylic acid: 28.8 g, 50% acrylamide: 181.
7 g was added, and 16 mol% of the anionic monomer was neutralized with 6.8 g of 30% by weight sodium hydroxide. Also,
Acrylic acid 2-methylpropanesulfonic acid monomer aqueous solution was neutralized to 50 mol% and then polymerized anionic polymer aqueous solution (molecular weight 700,000, concentration 20% by weight) 37.
Only 2g (6% of monomer) was added. Then, while stirring, nitrogen is introduced from the nitrogen introducing pipe to remove dissolved oxygen. During this time, the internal temperature is adjusted to 25 ° C. in a constant temperature water bath. After 30 minutes from the introduction of nitrogen, 3.1 g (to monomer, 25 ppm each) of 0.1 wt% ammonium peroxodisulfate and 0.1 wt% aqueous solution of ammonium hydrogen sulfite were added in this order to initiate polymerization. . After 1 hour and 50 minutes from the start of the polymerization, it was observed that the liquid surface of the reaction product was greatly raised and increased in viscosity, but the reaction was continued, and thereafter dispersed particles began to precipitate. Eight hours after the initiation of the polymerization, the same amount of each of the above initiators was added, and the polymerization was continued for another 12 hours to complete the reaction. This prototype is referred to as Comparison-1. The molar ratio of 2-acrylamido-2-methylpropanesulfonic acid / acrylic acid / acrylamide of this comparison-1 is 7 /
The viscosity was 13/80 and the viscosity was 450 mPa · s.
As a result of microscopic observation, it was found that the particles were 3 to 20 μm. The results are shown in Table 3.

[0040]

Comparative Examples 2 to 4 By the same operation as in Comparative Example 1, dispersions having compositions as shown in Table 1 were synthesized using only the synthetic polymers C, E and J as the dispersants. The results are shown in Table 3.

[0041]

Comparative Examples 5 to 8 By the same operation as in Comparative Example 1, only the natural polymers K, L, M and Q were used as the dispersant, respectively.
A dispersion having the composition as shown below was synthesized. The results are shown in Table 3.

[0042]

[Table 1] AMP: 2-acrylamido 2-methylpropane sulfonic acid AAC: acrylic acid, AAM: acrylamide, IA:
The amount of itaconic acid added is based on the monomers (% by weight), the ratio of the monomers is mol%,
Dispersion viscosity: mPa · s

[0043]

[Table 2] AMPS; 2-acrylamide 2-methylpropanesulfonic acid AAM; acrylamide, MAC; methacrylic acid, V
P; vinylpyrrolidone ion equivalent; meq / g

[0044]

[Table 3] Dispersion viscosity: mPa · s Weight average molecular weight: Unit is 10,000

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08L 5/00 C08L 5/00 5/04 5/04 5/06 5/06 F-term (reference) 4J002 AA01W AA02W AB01Y AB02Y AB03Y AB04Y AB05Y BC12W BC12X BG01X BG07X BG10X BG13W BG13X BH00W BH00X BH02X BJ00X BQ00W FD20X FD20Y GD04 GK00 HA06 4J011 JA06 JA08 JA10 JB14 JB26

Claims (14)

[Claims] 1. An anionic and / or nonionic water-soluble polymer fine particle having a particle size of 100 μm or less in a salt aqueous solution, and a synthetic polymer or a natural polymer soluble as a dispersant in the salt aqueous solution. , A water-soluble polymer dispersion liquid in which at least one or more of them coexist. 2. An anionic and / or nonionic water-soluble polymer is a monomer 0 to 10 represented by the following general formula (1).
A monomer (mixture) consisting of 0 mol%, 0 to 100 mol% of (meth) acrylamide and 0 to 30 mol% of another non-ionic copolymerizable monomer is dispersed and polymerized in an aqueous salt solution with stirring. The water-soluble polymer dispersion according to claim 1, which is produced by [Chemical 1] General formula (1) R1 is hydrogen, a methyl group or a carboxymethyl group, A is SO3, C6H4SO3, CONHC (CH3) 2CH
2SO3, C6H4COO or COO, R2 is hydrogen or COOY2, Y1 or Y2 is hydrogen or cation 3. The synthetic polymer has the following general formula (2):
Alternatively, the water-soluble polymer dispersion liquid according to claim 1, which is selected from polymers having one or more structural units represented by (3). [Chemical 2] General formula (2) Here, R3 is hydrogen or a methyl group, X is CN, CONR
5R6 (R5 and R6 are hydrogen, an alkyl group having 1 to 4 carbon atoms or an alkoxyl group), OR7 (R7 is hydrogen or an alkyl group having 1 to 4 carbon atoms or an alkoxyl group, an acyl group), NHCOR8 (R8 is hydrogen, An alkyl group or an alkoxyl group having 1 to 4 carbon atoms), and 1 to 10 carbon atoms
Is an alkyl group, an alkoxyl group, an aryl group, a nonionic hetero 5-membered ring or a 6-membered ring, and R4 represents hydrogen or an alkyl group having 1 to 3 carbon atoms. General formula (3) R5 is hydrogen, a methyl group or a carboxymethyl group, Q is SO3, C6H4SO3, CONHC (CH3) 2CH
2SO3, C6H4COO or COO, R6 represents hydrogen or COOY4, Y3 or Y4 represents hydrogen or cation, respectively. 4. The synthetic polymer is anionic,
The water-soluble polymer dispersion liquid according to claim 3, wherein an ion equivalent value is 1.0 to 11 meq / g. 5. The natural polymer is one or more selected from starch, starch derivatives, cellulose derivatives, alginates, pectin, gum arabic, locust bean gum and guar gum. The water-soluble polymer dispersion according to claim 1. 6. The natural polymer is anionic,
The water-soluble polymer dispersion according to claim 5, having an ion equivalent value of 1.0 to 7.0. 7. The weight average molecular weight of the anionic and / or nonionic water-soluble polymer constituting the polymer dispersion is 2
The water-soluble polymer dispersion according to claim 1, wherein the water-soluble polymer dispersion is at least, 000,000 and at most 20,000,000. 8. The water-soluble polymer dispersion according to claim 1, wherein the salt constituting the aqueous salt solution contains at least one polyvalent anion salt. 9. In a salt solution, at least one kind of a synthetic polymer and a natural polymer, which are soluble in the salt solution, are allowed to coexist as a dispersant and are represented by the general formula (1). 0 to 100 mol% of monomer and 0 of (meth) acrylamide
˜100 mol% and 0 to 30 mol% of another non-ionic copolymerizable monomer (mixture) with stirring,
A method for producing a water-soluble polymer dispersion liquid comprising fine particles having a particle diameter of 100 μm or less, which is characterized by dispersion polymerization. 10. The synthetic polymer according to claim 9, wherein the synthetic polymer is selected from polymers having one or more structural units represented by the general formula (2) or (3). Method for producing water-soluble polymer dispersion. 11. The method for producing a water-soluble polymer dispersion according to claim 10, wherein the synthetic polymer is anionic and has an ion equivalent value of 1.0 to 11 meq / g. . 12. The natural polymer is one or more selected from starch, starch derivatives, cellulose derivatives, alginates, pectin, acacia, locust bean gum and guar gum. The method for producing a water-soluble polymer dispersion according to claim 9. 13. The method for producing a water-soluble polymer dispersion according to claim 12, wherein the natural polymer is anionic and has an ionic equivalent value of 1.0 to 7.0. 14. The method for producing a water-soluble polymer dispersion according to claim 9, wherein the salt constituting the aqueous salt solution contains at least one polyvalent anion salt.