KR900002459B1 - Water soluble acrylate acrylamide copolymer - Google Patents

Abstract

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Description

Process for preparing water soluble polymer dispersion

The present invention relates to a method for producing a widely used water-soluble polymer dispersion, such as a coagulant for wastewater treatment, a dehydrating agent, a papermaking chemical, a dispersion stabilizer for various suspensions, a soil improving agent and the like.

Conventionally, as described above, as a method for producing a water-soluble polymer used in the field of the present invention, a stationary polymerization method in an aqueous solution, a water-in-oil emulsion polymerization method (Japanese Patent Application Laid-open No. 102388/1979 No.) and suspension polymerization method (Japanese Patent Application Laid-Open No. 69196/1979) in hydrophobic solvents.

In addition, the precipitation polymerization method in aqueous salt solution was described in Japanese Patent Application Laid-Open No. 70489/1975, and the polymerization method in aqueous salt solution mainly composed of acrylic acid having low pH was described in Japanese Patent Application No. 14907/1971.

In the fixed polymerization method in aqueous solution, since the polymerization is carried out at a monomer concentration of 10% by weight or more to obtain a high molecular weight polymer, the product cannot be easily dissolved because it is a hydrated gel type. Therefore, it is necessary to dilute and market it as a fluid low concentration product or to dry it to powder. When it is made at a low concentration and commercially available, there is a disadvantage in that the transport cost is increased, whereas when it is made in powder, it requires a lot of heat energy required for drying, and there is a disadvantage in that a three-dimensional crosslinking is performed and a water-insoluble part is generated.

Oily emulsions are flammable and have the drawback of wasting valuable organic solvents. In suspension polymerization in hydrophobic solvents, flammable substances such as cyclohexane, toluene, and the like are used, which causes a drawback that a huge cost is required for the production apparatus.

Although precipitation polymerization in aqueous salt solution is cheap and good in terms of equipment cost, there is a drawback that the polymers formed tend to stick together and become larger and larger, making them very difficult to handle.

In the invention described in Japanese Patent Publication No. 14907/1971, the dispersion is stable only in an acidic state and the dispersion becomes a gel when the carboxyl group is decomposed. However, since anionic coagulants generally have an effect by decomposing carboxyl groups and extending polymer chains, acidic coagulants do not have a satisfactory effect unless neutralized upon use except when used in high pH alkaline solutions. It is also difficult to produce polymer coagulants with anionicity of up to 15 mole percent, which is most effective as a coagulant.

The present invention is to obtain a dispersion of a water-soluble polymer by dissolving the monomer in an aqueous salt solution and then carrying out polymerization while precipitating the polymer in particulate form in the presence of a cavity with a dispersant. The aqueous salt solution should have the property of dissolving the monomer and precipitating the polymer.

As dispersants, polyhydric alcohols soluble in aqueous polymer electrolytes and / or salts are effective. If the precipitated polymer is an anionic or cationic polymer electrolyte, the polymer electrolyte used as the dispersant should have the same kind of charge as the precipitated polymer.

The amount of dispersant used should be at least 0.1% by weight based on aqueous salt solution. The polymer dispersion obtained has a low viscosity and good fluidity, which is convenient for transporting by pumping or dissolving. Since no organic solvent is used, there is no risk of ignition and the cost is low.

The present invention relates to a process for producing a water-soluble polymer dispersion having good fluidity, characterized in that a dispersant coexists when polymerizing an acrylic aqueous monomer (A) while stirring to precipitate a polymer in an aqueous salt solution.

Examples of the acrylic water-soluble monomer (A) include (meth) acrylamide, N, N-dimethylacrylamide, (meth) acrylic acid alkali metal salts, 2-acrylamido-2-methylpropanesulfonic acid alkali metal salts, and the following structural formulas (I): ) And cationic monomers represented by (II). :

In the above, R ₁ is H or CH ₃ ; R ₂ and R ₃ are each an alkyl group having 1 to ₃ carbon atoms; R ₄ is H or an alkanol group or alkyl group of 1-3 carbon atoms: A is an oxygen atom or NH; B is an alkylene group or hydroxypropylene group having 2 to 4 carbon atoms; And X ⁻ is an anionic counterion.

Although one or a combination of two or more of the above monomers can be selected, one requirement is that the polymer formed of the monomer (A) must be insoluble in the aqueous salt solution because the polymerization takes place while precipitating the polymer as described in claim 1. . With respect to acrylamide and the thin nonionic monomer, although the present invention can be practiced even in the case of a monopolymerization reaction, an ionic monomer other than the monomer of the structural formula (I) may be monopolymerized because the polymer can be dissolved in an aqueous salt solution. Can't.

For this reason, in the case of ionic monomers other than the formula (I), a copolymerization reaction with an anionic monomer such as acrylamide is preferable, and the amount thereof is suitably 15 mol% or less.

In the case of the cationic monomer of formula (I), the resulting hydrophobic benzyl group is attached to the amino group. The monomer of formula (I) is not dissolved in the aqueous salt solution even in a monopolymerization reaction and can be used in a wide range.

Further, since the present invention relates to a method for producing a water-soluble polymer, the combination of monomers as long as the polymer of the water-soluble monomer (A) is water-soluble is not limited to those mentioned above. For example, to some extent water soluble monomers may be used, such as acrylonitrile or the like as long as the copolymer with the water soluble monomer (A) is water soluble.

The aqueous salt solution, the dispersion medium for polymerization, should not dissolve the polymerization product. Representative salts include sodium sulfate, ammonium sulfate, magnesium sulfate, aluminum sulfate, sodium chloride, sodium dihydrogen phosphate, diammonium hydrogen phosphate, dipotassium hydrogen phosphate, and mixtures of two or more of these salts. In addition to these salts, those which do not dissolve the polymerization product are included within the scope of the present invention.

Although the concentration of the aqueous salt solution is not particularly limited and depends on the molar ratio of the salt and the ionic monomer used, the solubility of 15% by weight to the upper limit is generally good. In addition, the viscosity of the dispersion can be reduced by adding a salt to the dispersion within the range of solubility after the polymerization reaction.

The amount of dispersant used is preferably 0.1% by weight or more based on the aqueous salt solution, and below 0.1% by weight is not preferable because the formed polymer cannot be obtained in a dispersed form and clings to a larger polymer. Examples of the polyhydric alcohol coexisting as a dispersant in the polymerization reaction include ethylene glycol, propylene glycol, glycerin, pentaerythritol, sorbitol, polyethylene glycol up to 600 molecular weight, polypropylene glycol and the like. But it is not limited thereto.

In addition, the polymer electrolyte which will coexist as a dispersant in the polymerization reaction is not particularly limited as long as it can be dissolved in an aqueous solution of salt used for the polymerization.

If the polymer formed is nonionic, such as polyacrylamide, a cationic polymer electrolyte or an anionic polymer electrolyte may be used, but if the polymer formed is anionic, the anionic polymer electrolyte is good and the cationic polymer electrolyte is good if it is cationic. .

The anionic polymer electrolyte is preferably a polymer containing an alkali metal alkali metal salt, a polymer of 2-acrylamido-2-methylpropanesulfonic acid alkali metal salt, or a copolymer containing 30 mol% or more thereof, and the cationic polymer electrolyte is represented by the following structural formula (III). Preference is given to copolymers containing 1 or more polymers of cation monomers) or 20 mol% or more thereof.

(Ⅲ)

In the above, R ₁ is H or CH ₃ ; R ₂ and R ₃ are each an alkyl group having 1-2 carbon atoms; R ₄ is H or an alkyl group of 1-2 carbon atoms; A is an oxygen atom or NH; B is an alkylene group or hydroxypropylene group having 2 to 4 carbon atoms; And X ⁻ is an anionic counterion.

Representative examples of the cationic monomer of formula (III) include dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, dimethylaminohydropropyl (meth) acrylate, and quaternization thereof with methyl chloride, dimethyl sulfate and the like ( quaternize), but all monomers satisfying formula (III) can be used.

The polymerization process is summarized below and described in more detail in the Examples.

After supplying the above-mentioned acrylic water-soluble monomer (A) to an aqueous salt solution in which a dispersant is already dissolved, oxygen is replaced with nitrogen gas, and then a polymerization initiator is added to start the polymerization reaction with stirring. When the polymerization is terminated, polymer particles having a particle diameter of 1 mm or less can be obtained in a dispersed form. At this time, the monomer concentration is 5 parts by weight or more based on 100 parts by weight of the aqueous solution, and when 5 parts by weight or less, it is not excellent in aqueous solution polymerization. On the other hand, the upper limit is when the fluidity of the product is lost.

The polymerization temperature depends on the type of polymerization initiator and is not particularly limited as long as the initiator is functioning well. In addition, the modifying agent is not particularly limited, and for example, a redox type, an azo type, or the like conventionally used may be used.

EXAMPLE

The invention is particularly illustrated by the following examples, but are not limited to these examples without departing from the scope of the invention.

Example 1

Into a 1 l detachable flask equipped with a stirrer, thermometer, reflux condenser and nitrogen inlet tube, with five branches, 75 g of acrylamide, 106.3 g of ammonium sulfate, 7.5 g of ethylene glycol and 311.2 g of deionized water were heated to 45 ° C. Its interior was replaced with nitrogen.

2.3 g of a 1% aqueous solution of 2,2'-azobis (2-amidinopropane) hydrochloride was further added as a polymerization initiator, followed by polymerization with stirring at 45 ° C. for 10 hours to form a polymer in the form of fine particles dispersed in an aqueous salt solution. Got.

The viscosity of this product was 2060 cps at 25 ° C., and the viscosity of the polymer was 30 cps at 0.5% in 1N aqueous sodium chloride solution.

Example 2

75 g of acrylamide, 50 g of ammonium sulfate, 25 g of diammonium phosphate, 3.8 g of glycerine and 296.2 g of deionized water were added to a detachable flask used in Example 1, and then heated to 40 ° C. and its interior was replaced with nitrogen.

0.75 g of an aqueous 1% ammonium persulfate solution and 0.75 g of an aqueous 1% sodium bisulfite solution were added again, followed by polymerization with stirring at 40 ° C. for 10 hours to obtain a polymer in the form of fine particles dispersed in the aqueous solution. The dispersion had a viscosity of 8400 cps at 25 ° C. and a polymer of 70.2 cps at 0.5% in 1N aqueous sodium chloride solution.

When 50 g of diammonium hydrogen phosphate was further added to the dispersion, the viscosity was reduced to 350 cps.

Example 3

In the detachable flask used in Example 1, 43.6 g (90 mol%) of acrylamide, 6.4 g (10 mol%) of sodium acrylate, 112.5 g of ammonium sulfate, 2.5 g of pentaerythritol, and 335 g of deionized water were added thereto. After heating up, the interior was replaced with nitrogen.

1 g of 1% aqueous ammonium persulfate solution and 1 g of 1% aqueous sodium bisulfite solution were further added, followed by polymerization with stirring at 40 ° C. for 10 hours to obtain a polymer in the form of fine particles dispersed in an aqueous salt solution.

The viscosity of this product was 1830 cps at 25 ° C. and the viscosity of the polymer was 25.5 cps at 0.5% in 1N aqueous sodium chloride solution.

Example 4

In the detachable flask used in Example 1, 51.5 g (90 mol%) of acrylamide, 23.5 g (10 mol%) of sodium 2-acrylamido-2-methylpropanesulfonate, 106.3 g of ammonium sulfate, 3.8 g of sorbitol, After adding 3.8 g of propylene glycol and 311.1 g of deionized water, the mixture was heated to 45 ° C. and its interior was replaced with nitrogen.

3.8 g of a 1% aqueous solution of 2,2'-azobis (2-amidinopropane) hydrochloride was further added to the flask, followed by polymerization while stirring at 45 DEG C for 10 hours to form a polymer in the form of fine particles dispersed in an aqueous salt solution. Got it.

The viscosity of this product was 910 cps at 25 ° C. and the polymer had a viscosity of 40.7 cps at 0.5% in 1N aqueous sodium chloride solution.

Example 5

In a detachable flask used in Example 1, 57.6 g (90 mol%) of acrylamide, 4.2 g (5 mol%) of sodium acrylate, 13.2 g (5 mol%) of sodium 2-acrylamido-2-methylpropanesulfonate ), 63.8 g of ammonium sulfate, 42.5 g of sodium chloride, polyethylene glycol # 400 (7.5 g) and 311.2 g of deionized water were added and heated to 45 ° C., and the inside was replaced with nitrogen.

2.3 g of 1% aqueous ammonium persulfate solution and 2.3 g of 1% sodium bisulfite aqueous solution were further added, followed by polymerization with stirring at 45 ° C. for 10 hours to obtain a polymer in the form of fine particles dispersed in an aqueous salt solution.

The viscosity of this product was 1200 cps at 25 ° C. and the viscosity of the polymer at 0.5% in 1N aqueous sodium chloride solution was 35.1 cps.

Example 6

In the detachable flask used in Example 1, 52.7 g (90 mol%) of acrylamide, 22.3 g (10 mol%) of acryloyloxyethyldimethylbenzyl ammonium chloride, 51 g of aluminum sulfate, 34 g of sodium sulfate, 3.8 g of glycerin and deionized water After adding 336.2 g, it was heated to 45 ° C. and its inside was replaced with nitrogen.

1.5 g of a 1% aqueous solution of 2,2'-azobis (2-amidinopropane) hydrochloride was added thereto, followed by polymerization with stirring at 45 ° C. for 10 hours to obtain a polymer in the form of fine particles dispersed in an aqueous salt solution.

The viscosity of this product was 2100 cps at 25 ° C. and the viscosity of the polymer was 40.3 cps at 0.5% in 1N aqueous sodium chloride solution.

Example 7

In the detachable flask used in Example 1, 35.3 g (65 mol%) of acrylamide, 45.4 g (22 mol%) of acryloyloxyethyldimethylbenzyl ammonium chloride, 19.3 g (13 mol) of acryloyloxyethyltrimethylammonium chloride %), 68.8 g of ammonium sulfate, 2.5 g of ethylene glycol, polyethylene glycol # 200 (2.5 g) and 270 g of deionized water were added thereto, and then heated to 45 ° C., and the inside thereof was replaced with nitrogen.

2 g of a 1% aqueous solution of 2,2'-azobis (2-amidinopropane) hydrochloride was added again, followed by polymerization with stirring at 45 ° C. for 10 hours to obtain a polymer in the form of fine particles dispersed in an aqueous salt solution. The viscosity of this dispersion was 2500 cps at 25 ° C. and the polymer viscosity at 0.5% in 3% aqueous sodium sulfate solution was 50.6 cps.

When 56.2 g of diammonium hydrogen phosphate was further added to the dispersion, the viscosity was reduced to 390 cps.

Example 8

In the detachable flask used in Example 1, 56.6 g (90 mol%) acrylamide, 18.4 g (10 mol%) methacryloyloxyethyltrimethylammonium chloride, 51 g ammonium sulfate, 34 g diammonium hydrogen phosphate, 2.3 g glycerin, 1.5 g of ethylene glycol and 336.2 g of deionized water were added, and then heated to 50 ° C., and the inside was replaced with nitrogen.

1.5 g of a 1% aqueous solution of 2,2'-azobis (2-amidinopropane) hydrochloride was further added, followed by polymerization with stirring at 50 ° C. for 10 hours to obtain a polymer in particulate form dispersed in an aqueous salt solution.

The viscosity of this product was 3510 cps at 25 ° C. and the viscosity of the polymer at 0.5% in 1N aqueous sodium chloride solution was 15.1 cps.

In addition, a polymer electrolyte that can be dissolved in a saline solution together with a polyhydric alcohol can be used. This example is shown in Examples 9 and 10.

Example 9

In the detachable flask used in Example 1, 3.8 g of sodium acrylate homopolymer (the viscosity of an aqueous solution with a pure component of 0.5% was 10 cps at 25 ° C.), 50 g of ammonium sulfate, 25 g of diammonium hydrogen phosphate, 3.8 g of propylene glycol and 292.4 g of deionized water was added to dissolve it, and then 75 g of acrylamide was added thereto, and heated to 45 ° C., and the inside was replaced with nitrogen.

2.3g of an aqueous 1% ammonium persulfate solution and 2.3g of an aqueous 1% sodium bisulfite solution were further added, followed by polymerization with stirring at 45 ° C. for 10 hours to obtain a polymer in the form of fine particles dispersed in an aqueous salt solution. The dispersion had a viscosity of 7200 cps at 25 ° C. and a polymer of 35.3 cps at 0.5% in 1N aqueous sodium chloride solution.

When 50 g of potassium sulfate was added to this dispersion, the viscosity was reduced to 450 cps.

Example 10

In the detachable flask used in Example 1, 2.3 g of a homopolymer of acryloyloxyethyl trimethylammonium chloride (the viscosity of its aqueous solution with 0.5% pure component is 20 cps at 25 ° C.), 85 g of ammonium sulfate, 3.8 of glycerin and After dissolving by adding 333.9 g of ionized water, 34.7 g (75 mol%) of acrylamide, 31.5 g (18 mol%) of acryloyloxyethyltrimethylbenzyl ammonium chloride and 8.8 g (7 mol%) of acryloyloxyethyltrimethylammonium chloride ) Was further added, then heated to 45 ° C. and replaced with nitrogen inside.

2.3 g of a 1% aqueous solution of 2,2'-azobis (2-amidinopropane) hydrochloride was further added, followed by polymerization with stirring at 45 ° C. for 10 hours to obtain a polymer in the form of fine particles dispersed in an aqueous salt solution.

The viscosity of this product was 720 cps at 25 ° C. and the polymer was 65 cps at 0.5% in 3% aqueous sodium sulfate solution.

Example 11

In a detachable flask used in Example 1, 7.5 g of sodium acrylate homopolymer (the viscosity of an aqueous solution with 0.5% pure component is 10 cps at 25 ° C.), 42.5 g ammonium sulfate, 42.5 g diammonium hydrogen phosphate and 331.8 g deionized water After addition, 75 g of acrylamide and 0.75 g of isopropyl alcohol as a chain transfer agent were added, followed by heating to 40 ° C. and replacing the inside thereof.

0.75 g of an aqueous 1% ammonium persulfate solution and 0.75 g of an aqueous 1% sodium bisulfite solution were further added as a polymerization initiator, followed by polymerization while stirring at 40 ° C. for 10 hours to obtain a polymer in the form of fine particles dispersed in a saline solution.

The viscosity of this product was 2300 cps at 25 ° C. and the viscosity of the polymer was 40.2 cps at 0.5% in 1N aqueous sodium chloride solution.

Example 12

In a detachable flask used in Example 1 7.5 g of sodium 2-acrylamido-2-methylpropanesulfonate (the viscosity at 0.5% pure component is 20 cps at 25 ° C.), 100 g ammonium sulfate and 292.5 g deionized water Was added and dissolved, then 75 g of acrylamide was added and heated to 45 ° C. and its interior was replaced with nitrogen.

0.75 g of an aqueous 1% ammonium persulfate solution and 0.75 g of an aqueous 1% sodium bisulfite solution were added again, followed by polymerization with stirring at 45 ° C. for 10 hours to obtain a polymer in the form of fine particles dispersed in a saline solution. The dispersion had a viscosity of 7500 cps at 25 ° C. and a polymer of 65 cps at 0.5% in 1N aqueous sodium chloride solution.

When 25 g of diammonium hydrogen phosphate was further added to the dispersion, the viscosity was reduced to 550 cps.

Example 13

In a detachable flask used in Example 1 2.5 g of sodium acrylate homopolymer (the viscosity of an aqueous solution of 0.5% pure component is 10 cps at 25 ° C.), a step of sodium 2-acrylamido-2-methylpropanesulfonate 2.5 g of polymer (the viscosity of an aqueous solution with a pure component of 0.5% is 30 cps), 112.5 g of ammonium sulfate and 332.5 g of deionized water are added and dissolved. 43.6 g (90 mol%) of acrylamide and 6.4 g (10 of sodium acrylate) Molar%) was added again and then heated to 45 ° C. and its interior replaced with nitrogen.

1.5 g of a 1% aqueous solution of 2,2'-azobis (2-amidinopropane) hydrochloride was added thereto, followed by polymerization with stirring at 45 ° C. for 10 hours to obtain a polymer in the form of fine particles dispersed in a saline solution.

The viscosity of this product was 3800 cps at 25 ° C. and the viscosity of the polymer was 35.5 cps at 0.5% in 1N aqueous sodium chloride solution.

Example 14

7.5 g of a homopolymer of sodium 2-acrylamido-2-methylpropanesulfonate in a detachable flask used in Example 1 (the viscosity of an aqueous solution with 0.5% pure component is 19 cps at 25 ° C.), 106.3 g of ammonium sulfate And 310.5 g of deionized water was added to dissolve it, 51.5 g (90 mol%) of acrylamide, 23.5 g (10 mol%) of sodium-2-acrylamido-2-methylpropanesulfonate and 0.75 benzyl alcohol as chain transfer agents. g was added again and heated to 45 ° C. and its interior replaced with nitrogen.

2.3 g of a 1% aqueous solution of 2,2'-azobis (2-amidinopropane) hydrochloride was added again, followed by polymerization with stirring at 45 ° C. for 10 hours to obtain a polymer in particulate form dispersed in a saline solution.

The viscosity of this product was 1500 cps at 25 ° C. and the polymer had a viscosity of 25 cps at 0.5% in 1N aqueous sodium chloride solution.

Example 15

In a detachable flask used in Example 1, 7.5 g of a homopolymer of sodium acrylate (the viscosity of an aqueous solution of 0.5% pure component was 10 cps at 25 ° C.), 51 g of ammonium sulfate, 34 g of diammonium hydrogen phosphate and 331.8 g of deionized water After dissolving, 57.6 g (90 mol%) of acrylamide, 4.2 g (5 mol%) of sodium acrylate, 13.2 g (5 mol%) of sodium 2-acrylamido-2-methylpropanesulfonate and the chain before 0.75 g of isopropyl alcohol was then added again, then heated to 40 ° C. and its interior replaced with nitrogen.

1.5 g of 1% aqueous ammonium persulfate solution and 1.5 g of 1% aqueous sodium bisulfite solution were further added, followed by polymerization while stirring at 40 ° C. for 10 hours to obtain a polymer in the form of fine particles dispersed in a saline solution.

The viscosity of this product was 1030 cps at 25 ° C. and the viscosity of the polymer was 30 cps at 0.5% in 1N aqueous sodium chloride solution.

Example 16

In a detachable flask used in Example 1, 3.8 g of a homopolymer of acryloyloxyethyltrimethylammonium chloride (the viscosity of an aqueous solution with 0.5% pure component was 20 cps at 25 ° C.), 51 g of aluminum sulfate, 34 g of sodium sulfate, and deionized water After dissolving 336.2g, 75g of acrylamide was added, heated to 50 ° C, and the inside was replaced with nitrogen.

1.5 g of a 1% aqueous solution of 2,2′-azobis (2-amidinopropane) hydrochloride was added again, followed by polymerization at 50 ° C. for 10 hours to obtain a polymer in particulate form dispersed in saline solution.

The viscosity of this product was 4100 cps at 25 ° C. and the viscosity of the polymer was 55 cps at 0.5% in 1N aqueous sodium chloride solution.

Example 17

In a detachable flask used in Example 1, 3.8 g of methacryloyloxyethyl trimethylammonium chloride homopolymer (the viscosity of an aqueous solution with 0.5% pure component was 100 cps at 25 ° C.), 106.3 g of ammonium sulfate and 314.9 g of deionized water 56.6 g (90 mol%) of acrylamide and 18.4 g (10 mol%) of methacryloyloxyethyl trimetalammonium chloride were further added, and then heated to 45 DEG C, and the inside was replaced with nitrogen. .

1.5 g of 1% ammonium persulfate aqueous solution and 1.5 g of 1% sodium hydrogen sulfite aqueous solution were further added, followed by polymerization while stirring at 45 ° C. for 10 hours to obtain a polymer in the form of fine particles dispersed in a saline solution.

The viscosity of this product was 2550 cps at 25 ° C. and the viscosity of the polymer was 20.3 cps at 0.5% in 1N aqueous sodium chloride solution.

Comparative Example 1

112.5 g of ammonium sulfate and 337.5 g of deionized water were added to the detachable flask used in Example 1, and then dissolved. 35.1 g (90 mol%) of acrylamide and 14.9 g (10 mol) of acryloyloxyethyldimethylbenzylammonium chloride %) Was further added and heated to 50 ° C. and its interior was replaced with nitrogen.

After adding 1.0 g of a 1% aqueous solution of 2,2'-azobis (2-amidinopropane) hydrochloride and then polymerizing with stirring at 50 ° C. for 10 hours, the polymer was dispersed in the form of particles having a particle diameter of 2 to 3 mm. However, when the co-existing polymer was not present as described above, these particles stuck together after overnight staying and became large lumps and did not disperse again.

Comparative Example 2

112.5 g of ammonium sulfate and 337.5 g of deionized water were added to the detachable flask used in Example 1 and then dissolved. Then 50 g of acrylamide was added again, heated to 40 ° C., and the inside was replaced with nitrogen.

1 g of 1% aqueous ammonium persulfate solution and 1 g of 1% aqueous sodium hydrogen sulfite solution were further added, and the polymerization was carried out while stirring at 40 ° C., but after 10 minutes, the viscosity increased and the whole system became a mass.

Claims (13)

A method of polymerizing an acrylic water-soluble monomer that precipitates a polymer while stirring in a saline solution, wherein the dispersant is coexisted. The salt according to claim 1, wherein the salt is sodium sulfate, ammonium sulfate, magnesium sulfate, aluminum sulfate, sodium chloride, sodium dihydrogen phosphate, diammonium hydrogen phosphate, dipotassium hydrogen phosphate, or a mixture thereof, and has a salt concentration of at least 15% by weight and is water-soluble. A method for producing a water-soluble polymer dispersion in a saline solution in which the polymer of the monomer (A) is not dissolved and the dispersant (B) is dissolved. The method for producing a water-soluble polymer dispersion according to claim 1, wherein the dispersant is a polyhydric alcohol. The method for producing a water-soluble polymer dispersion according to claim 1, wherein the dispersant is a polymer electrolyte. 4. The method for producing a water-soluble polymer dispersion according to claim 3, wherein the polyhydric alcohol is one or two or more mixtures selected from ethylene glycol, propylene glycol, glycerin, pentaerythritol, and sorbitol. The method for producing a water-soluble polymer dispersion according to claim 3, wherein the polyhydric alcohol is polypropylene glycol and / or polyethylene glycol up to molecular weight 600. The water-soluble polymer according to claim 1, wherein the water-soluble monomer (A) is a mixture of one or more cationic monomers of the following structural formula (I) and other acrylic water-soluble monomers copolymerizable therewith (molar ratio 100: 0 to 5:95). Preparation of Dispersion:

(Ⅰ) In the above, R ₁ is H or CH ₃ : R ₂ and R ₃ are each an alkyl group having 1 to ₃ carbon atoms; A is an oxygen atom or NH; B is an alkylene group or hydroxypropylene group having 2 to 4 carbon atoms; X ⁻ is an anionic counterion. The process for producing a water-soluble polymer dispersion according to claim 1, wherein at least 85 mol% of the water-soluble monomer (A) is acrylamide. The method of claim 1, wherein the water-soluble monomer (A) is acrylamide and the dispersant (B) is 30-100 mol% of an alkali metal salt of acrylic acid and / or 2-acrylamido-2-methylpropanesulfonic acid alkali metal salt and copolymerizable therewith. It is a copolymer containing 0-70 mol% of acrylic water-soluble monomers, The manufacturing method of the water-soluble polymer dispersion characterized by the above-mentioned. The water-soluble monomer (A) is a monomer mixture of the (meth) acrylic acid alkali metal salt and the (meth) acrylamide, the (meth) acrylic acid alkali metal salt is 15 mol or less, and the dispersant (B) is the acrylic acid alkali metal salt and / Or a copolymer containing 30 to 100 mol% of 2-acrylamido-2-methylpropanesulfonic acid alkali metal salt and 0 to 70 mol% of other acrylic water-soluble monomers copolymerizable therewith. . The water-soluble monomer (A) is a monomer mixture of 2-acrylamido-2-methylpropanesulfonic acid alkali metal salt and (meth) acrylamide, and the 2-acrylic acido-2-methylpropanesulfonic acid alkali metal salt 15 mole% or less and the dispersant (B) is 30 to 100 mole% of the alkali metal salt of acrylic acid and / or 2-acrylamido-2-methylpropanesulfonic acid alkali metal salt and 0 to 70 mole% of other acrylic water-soluble monomers copolymerizable therewith. Method for producing a water-soluble polymer dispersion, characterized in that the copolymer containing. The water-soluble polymer dispersion according to claim 1, wherein the water-soluble monomer (A) is acrylamide and the dispersant (B) is a polymer containing at least one cationic monomer of the following structural formula (III) or a copolymer containing at least 20 mol% thereof. Manufacturing method.

(Ⅲ) In the above, R ₁ is H or CH ₃ ; R ₂ and R ₃ are each an alkyl group having 1-2 carbon atoms; R ₄ is H or an alkyl group of 1-2 carbon atoms; A is an oxygen atom or NH; B is an alkylene group or hydroxypropyl group of 2-4 carbon atoms; X ⁻ is an anionic counterion. The method of claim 1, wherein the water-soluble monomer (A) is a monomer mixture of at least one cationic monomer of the following structural formula (II) and (meth) acrylamide, the monomer of the structural formula (II) is 15 mol% or less, and a dispersant (B). ) Is a polymer of at least one cationic monomer having the structural formula (III) as defined in claim 12 or a copolymer comprising at least 20 mol% thereof.

(Ⅱ) In the above, R ₁ is H or CH ₃ , R ₂ and R ₃ are each an alkyl group of 1-3 carbon atoms; R ₄ is H or an alkyl or alkanol group of 1-3 carbon atoms; And X ⁻ is an anionic counterion.