WO2011154991A1 - Polymer flocculating agent and method for producing same - Google Patents

Abstract

Provided is a polymer flocculating agent. When dissolved in water, said polymer flocculating agent shows a high dissolution rate and has a small content of water-insoluble matters and, therefore, can improve the flocculation performance. When used in treating sludge or wastewater, said polymer flocculating agent forms solid and large flocs, the thus formed flocs being hardly broken or re-dispersed, and therefore can highly improve the stability of the flocculation treatment and the treatment speed. Even at a low addition level, said polymer flocculating agent enables the flocculation treatment and, after dehydrating the sludge, gives a cake with a low water content, which makes it possible to reduce the amount of waste matters and incineration cost. The polymer flocculating agent comprises dry particles of a water-soluble (co)polymer (A) obtained by a reverse phase suspension polymerization process, which comprises dropping an aqueous monomer solution, said aqueous monomer solution containing a water-soluble unsaturated monomer (a) and a polymerization initiator (d), into a liquid mixture of a hydrophobic dispersion medium (b) with a dispersing agent (c), and said particles comprise secondary particles formed by agglomerated single particles (primary particles).

Description

Polymer flocculant and method for producing the same

The present invention relates to a polymer flocculant. More specifically, the present invention relates to a polymer flocculant useful for dewatering sewage sludge, for coagulating sedimentation of industrial wastewater, for improving drainage yield or increasing paper strength in the papermaking process, and for tertiary recovery of petroleum.

Conventionally, polymer flocculants composed of water-soluble polymers are used for dewatering treatment of sewage or human waste (hereinafter abbreviated as sewage sludge), for agglomeration / sedimentation treatment of general industrial wastewater (hereinafter abbreviated as waste water), It is widely used as an agent for treating muddy water, for promoting sedimentation and separation of muddy water at the time of reclamation, and as a drainage yield improver and paper strength enhancer for papermaking.

Among the polymer flocculants, for example, for the dehydration treatment of sewage sludge, a cation comprising a water-soluble polymer such as poly (meth) acryloyloxyethyltrimethylammonium chloride, acrylamide-acryloyloxyethyltrimethylammonium chloride copolymer, polyvinylamidine, etc. An amphoteric polymer flocculant made of a water-soluble polymer such as an ionic polymer flocculant (see, for example, Patent Document 1) and acrylamide-acrylic acid- (meth) acryloyloxyethyltrimethylammonium chloride copolymer is widely known (for example, , See Patent Document 2).

As a chemical for waste water coagulation / precipitation treatment or in the civil engineering field, water-soluble polymers such as polyvinyl alcohol and polysaccharides other than the polymer coagulant, and (meth) acrylamide, (meth) acrylic acid, etc. An anionic polymer flocculant made of a water-soluble polymer whose graft density is increased by graft polymerization of a water-soluble monomer is also known (see, for example, Patent Documents 3 and 4).

However, the polymer flocculants described in Patent Documents 1 and 2 have a small floc particle size generated during the treatment of sewage sludge and poor drainage, and a filter cloth when a dehydrator such as a belt press or a filter press is used. It was difficult to obtain a sufficient dehydration effect, for example, the peelability between the cake and the solid matter was poor, and the water content of the solid-liquid separated cake was high.
In addition, even the polymer flocculants described in Patent Documents 3 to 4 have a small floc particle size generated during the treatment of waste water, etc., a slow filtration rate, a low suspended solids recovery rate (hereinafter SS recovery rate), a cake water content Again, it was difficult to obtain a sufficient treatment effect such as a high rate.

Therefore, in order to solve these problems, a polymer flocculant composed of a water-soluble polymer obtained by a reverse phase suspension polymerization method has been proposed. In the reversed-phase suspension polymerization method, the water for the polymerization reaction is easily removed by the hydrophobic dispersion medium used, and the polymerization at a constant temperature is easy. The polymer flocculant can be obtained, and the polymer flocculant is said to solve the above problems.

JP 63-274409 A Japanese Unexamined Patent Publication No. 3-189000 JP-A-6-254305 JP-A-6-254306 Japanese Patent No. 1303149 Japanese Patent No. 1303161 Japanese Patent No. 1391345

However, in the case of a polymer flocculant composed of a water-soluble polymer by the reverse-phase suspension polymerization method described in Patent Documents 5 to 7, the above-mentioned problems are solved. There was a problem that it easily adheres to the stirring blades.
In addition, the polymer flocculant obtained is easy to roll because it is in the form of beads, and the powder fluidity is too high, so when treating sewage sludge, waste water, etc. (hereinafter sometimes referred to as sewage sludge), a water dissolution tank There was a problem that a stable quantitative supply with an automatic weighing device could not be performed.

The inventors of the present invention have arrived at the present invention as a result of intensive studies to solve these problems. That is, the present invention reverses by dropping a monomer aqueous solution containing a water-soluble unsaturated monomer (a) and a polymerization initiator (d) into a mixture of a hydrophobic dispersion medium (b) and a dispersant (c). Polymer aggregation comprising dry particles of water-soluble (co) polymer (A) obtained by phase suspension polymerization, wherein the particles contain secondary particles obtained by combining single particles (primary particles) It is an agent.

The polymer flocculant of the present invention has the following effects.
(1) There is little adhesion to the wall surface in the polymerization tank during production.
(2) Since it has moderately excellent powder fluidity, it can be quantitatively supplied using a powder feeder or the like.
(3) Since the dissolution rate at the time of water dissolution is high and the amount of water insoluble matter is small, the aggregation performance can be enhanced.
(4) Form strong coarse flocs in the treatment of sludge and wastewater.
(5) Since the formed floc is not easily broken or redispersed, the stability and processing speed of the aggregation treatment can be remarkably increased.
(6) The agglomeration can be performed with a small amount of addition, and the moisture content of the cake after the sludge dehydration step is low, so the amount of waste and incineration costs can be reduced.

[Water-soluble (co) polymer (A)]
The water-soluble (co) polymer (A) in the present invention comprises an aqueous monomer solution containing a water-soluble unsaturated monomer (a) and a polymerization initiator (d), a hydrophobic dispersion medium (b) and a dispersant (c). It is dripped in this liquid mixture and reverse phase suspension polymerization is carried out.
The water-soluble unsaturated monomer (a) includes the following nonionic monomer (a1), cationic monomer (a2), anionic monomer (a3), and a mixture of two or more thereof.

As the monomer constituting (A), in addition to (a), a water-insoluble unsaturated monomer (x) and / or a crosslinkable monomer (y) may be used in combination as long as the effects of the present invention are not impaired. .
Here, the water-soluble unsaturated monomer or water-soluble (co) polymer means an unsaturated monomer or (co) polymer whose solubility in water (g / 100 g of water, 20 ° C., the same shall apply hereinafter) is 1 g or more. The water-insoluble unsaturated monomer means an unsaturated monomer having a solubility in water of less than 1 g.

In the following, the number average molecular weight measured by gel permeation chromatography (GPC) method is abbreviated as GMn, and the weight average molecular weight is abbreviated as GMw. The GMn and GMw are obtained under the following GPC measurement conditions.
<GPC measurement conditions>
Apparatus: HLC-802A, manufactured by Tosoh Corporation Column: TSK gel GMH6 (two) [Tosoh Corporation]
Measurement temperature: 40 ° C
Sample solution: 0.5 wt% tetrahydrofuran solution solution injection amount: 200 μl
Detector: Refractive index detector Standard: Polystyrene

(A1) Nonionic monomer The following are mentioned, and these mixtures.
(A11) (Meth) acrylate Carbon number (hereinafter abbreviated as C) 4 or more and GMn 5,000 or less, for example, hydroxyl group-containing (meth) acrylate [hydroxyethyl-, diethylene glycol mono-, polyethylene glycol (degree of polymerization 3 to 50) mono -And polyglycerol (degree of polymerization 1 to 10) mono (meth) acrylate etc.], alkyl acrylate (alkyl group is C1-2) ester (C4-5, eg methyl acrylate, ethyl acrylate);
(A12) (Meth) acrylamide and derivatives thereof C3-30, such as (meth) acrylamide, N-alkyl (C1-3) (meth) acrylamide [N-methyl and -isopropyl (meth) acrylamide etc.], N-alkylol (Meth) acrylamide [N-methylol (meth) acrylamide etc.];
(A13) Nitrogen-containing ethylenically unsaturated compounds other than the above C3-30, such as acrylonitrile, N-vinylformamide, N-vinyl-2-pyrrolidone, N-vinylimidazole, N-vinylsuccinimide, N-vinylcarbazole and 2 -Cyanoethyl (meth) acrylate.

(A2) Cationic monomer The following are included, and salts thereof [for example, inorganic acid (hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, etc.) salts, methyl chloride salts, dimethyl sulfate salts, benzyl chloride salts], and mixtures thereof. .
(A21) Nitrogen atom-containing (meth) acrylate C5-30, such as aminoalkyl (C2-3) (meth) acrylate, N, N-dialkyl (C1-2) aminoalkyl (C2-3) (meth) acrylate [N N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-diethylaminopropyl (meth) acrylate, etc.], containing heterocyclic ring (Meth) acrylate [N-morpholinoethyl (meth) acrylate etc.];
(A22) Nitrogen atom-containing (meth) acrylamide derivative C5-30, such as N, N-dialkyl (C1-2) aminoalkyl (C2-3) (meth) acrylamide [N, N-dimethylaminoethyl (meth) acrylamide, etc. ];
(A23) an ethylenically unsaturated compound having an amino group C5-30, such as vinylamine, vinylaniline, (meth) allylamine, p-aminostyrene, etc.];
(A24) Compound having amine imide group C5-30, such as 1,1,1-trimethylamine (meth) acrylimide, 1,1-dimethyl-1-ethylamine (meth) acrylimide, 1,1-dimethyl-1- ( 2′-phenyl-2′-hydroxyethyl) amine (meth) acrylimide;
(A25) Nitrogen atom-containing vinyl monomers other than the above C5-30, such as 2-vinylpyridine, 3-vinylpiperidine, vinylpyrazine, vinylmorpholine.

(A3) Anionic monomer The following acids, salts thereof [alkali metal (lithium, sodium, potassium, etc., the same shall apply hereinafter) salts, alkaline earth metals (magnesium, calcium, etc., the same shall apply hereinafter) salts, ammonium salts and amines (C1-20) salts and the like], and mixtures thereof.
(A31) unsaturated carboxylic acid C3-30, such as (meth) acrylic acid, (anhydrous) maleic acid, fumaric acid, (anhydrous) itaconic acid, vinylbenzoic acid, allyl acetic acid;
(A32) Unsaturated sulfonic acid C2-20 aliphatic unsaturated sulfonic acid (such as vinyl sulfonic acid), C6-20 aromatic unsaturated sulfonic acid (such as styrene sulfonic acid), sulfo group-containing (meth) acrylate [sulfo Alkyl (C2-20) (meth) acrylate [2- (meth) acryloyloxyethanesulfonic acid, 2- (meth) acryloyloxypropanesulfonic acid, 3- (meth) acryloyloxypropanesulfonic acid, 2- (meth) acryloyl Oxybutanesulfonic acid, 4- (meth) acryloyloxybutanesulfonic acid, 2- (meth) acryloyloxy-2,2-dimethylethanesulfonic acid, p- (meth) acryloyloxymethylbenzenesulfonic acid, etc.], containing sulfo group (Meth) acrylamide [2- (meth) acryloylaminoe Tansulfonic acid, 2- and 3- (meth) acryloylaminopropanesulfonic acid, 2- and 4- (meth) acryloylaminobutanesulfonic acid, 2- (meth) acryloylamino-2,2-dimethylethanesulfonic acid, p -(Meth) acryloylaminomethylbenzenesulfonic acid and the like], alkyl (C1-20) (meth) allylsulfosuccinic acid ester [methyl (meth) allylsulfosuccinic acid ester and the like] and the like;
(A33) (Meth) acryloyl polyoxyalkylene (C1-6) sulfate ester (meth) acryloyl polyoxyethylene (degree of polymerization 2-50) sulfate ester and the like.

Of these, (a), (a1), (a21), (a22), (a31), (a32) are preferable, and (a12), (a13), (a21) are more preferable. , (A22), (a31), and (a32), a sulfo group-containing (meth) acrylate, a sulfo group-containing (meth) acrylamide, particularly preferably (meth) acrylamide of (a12), (a13) Acrylonitrile, N-vinylformamide of (a21), N, N-dialkylaminoalkyl (meth) acrylate of (a21) and salts thereof (above), (meth) acrylic acid of (a31), ( Maleic acid anhydride, (anhydrous) itaconic acid and their salts, 2- (meth) acryloyloxyethanesulfonic acid of (a32), 2- and 3- (meth) acryloyloxypropanesulfonic acid, 2- (meth) acryloylamino-2,2-dimethylethanesulfonic acid and salts thereof, most preferably (meth) acrylamide of (a12), (a21) (Meth) acryloyloxyethyl dialkylamine salt, (meth) acryloyloxyethyl trialkylammonium salt, (meth) acrylic acid (a31), and alkali metal salts thereof. Moreover, these (a) can be arbitrarily used together and can be copolymerized.

The content (mol%) of (a) based on the total number of moles of the monomer constituting (A) is agglomeration performance (high floc strength, coarse floc, low moisture content of dehydrated cake, etc.). From this point of view, it is preferably 55 to 100 mol%, more preferably 80 to 100 mol%.

Examples of the water-insoluble unsaturated monomer (x) that may be used in combination with (a) as necessary include the following (x1) to (x5) and mixtures thereof.
(X1) C6-23 (meth) acrylate (meth) acrylate of aliphatic or cycloaliphatic alcohol (C3-20) [propyl-, butyl-, lauryl-, octadecyl- and cyclohexyl (meth) acrylate etc.] and epoxy Group (C4-20) -containing (meth) acrylate [glycidyl (meth) acrylate and the like];

(X2) Unsaturated carboxylic acid monoester of [monoalkoxy (C1-20)-, monocycloalkoxy (C3-12)-or monophenoxy] polypropylene glycol (hereinafter abbreviated as PPG) (degree of polymerization 2-50) mono Allyl (C1-20) or monohydric phenol (C6-20) propylene oxide (hereinafter abbreviated as PO) adduct (meth) acrylate ester [ω-methoxy PPG mono (meth) acrylate, ω-ethoxy PPG mono ( Meth) acrylate, ω-propoxy PPG mono (meth) acrylate, ω-butoxy PPG mono (meth) acrylate, ω-cyclohexyl PPG mono (meth) acrylate, ω-phenoxy PPG mono (meth) acrylate, etc.] and diols (C2˜ 20) or dihydric phenol (C6-20) Of PO adduct (meth) acrylic acid ester [.omega.-hydroxyethyl (poly) oxypropylene mono (meth) acrylate, etc.] or the like;

(X3) C2-30 unsaturated hydrocarbon ethylene, nonene, styrene, 1-methylstyrene and the like;
(X4) carboxylic acid (C2-30) ester (vinyl acetate, etc.) of C2-4 unsaturated alcohol [for example, vinyl alcohol, (meth) allyl alcohol];
(X5) C2-30 halogen-containing monomer (for example, vinyl chloride).

Examples of the crosslinkable monomer (y) include the following (y1) to (y5) and salts thereof [for example, for basic monomers, inorganic acids (hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, (Sulfurous acid, phosphoric acid, nitric acid, etc.) salts, methyl chloride salts, dimethyl sulfate salts, benzyl chloride salts, etc., for acidic monomers, alkali metal salts, alkaline earth metal salts, amines (C1-20, such as methylamine, ethylamine, Cyclohexylamine) salts], and mixtures thereof.
(Y1) Bispoly (2-4 or more) (meth) acrylamide C5-30, such as N, N′-methylenebisacrylamide;
(Y2) poly (2-4 or more) (meth) acrylates C8-30, such as ethylene glycol di (meth) acrylate, pentaerythritol [poly (2-4)] (meth) acrylate;

(Y3) Vinyl group (2 to 20 or more) -containing monomer C4 or more and GMn 6,000 or less, such as divinylamine, polyvalent (2 to 5 or more) amine [C2 or more and GMn 3,000 or less, such as ethylenediamine , Polyethyleneimine (C4 or more and GMn3,000 or less)] poly (2-20) vinylamine, divinyl ether, polyhydric alcohol [C2 or more and GMn3,000 or less, such as alkylene (C2-6 or more) glycol [ethylene Glycol, propylene glycol, 1,6-hexanediol (hereinafter abbreviated as EG, PG, HD, etc.)], polyoxyalkylene [GMn 2,000 to 3000, such as polyethylene glycol (hereinafter abbreviated as PEG) (molecular weight 106 or more) And GMn 3,000 ), PPG (molecular weight 134 or more and GMn 3,000 or less), polyoxyethylene (molecular weight 106 or more and GMn 3,000 or less) / polyoxypropylene (molecular weight 134 or more and GMn 3,000 or less) block copolymer], trimethylolethane, Trimethylolpropane, pentaerythritol, sorbitol (hereinafter abbreviated as TME, TMP, GR, PE, SO, respectively), (poly) (2-50) glycerin (glycerin is abbreviated as GR), starch) 20) vinyl ether and the like;

(Y4) Allyl group (2 to 20 or more) -containing monomers C6 or more and GMn3,000 or less, such as di (meth) allylamine, N-alkyl (C1-20) di (meth) allylamine, polyvalent amine (above Poly (2-20) (meth) allylamine, di (meth) allyl ether, polyhydric alcohol (above) poly (2-20) (meth) allyl ether, poly (2-20) ( (Meth) allyloxyalkanes (C1-20) (such as tetraallyloxyethane);
(Y5) Epoxy group-containing monomer C8 or more and GMn6,000 or less, for example, EG diglycidyl ether, PEG diglycidyl ether, GR triglycidyl ether.

The content (mol%) of (x) is preferably 40 or less, based on the total number of moles of the monomer constituting (A), preferably from the viewpoint of aggregation performance and solubility of the polymer flocculant in water. It is 0.1 to 20, more preferably 0.5 to 10.
Further, the content (mol%) of (y) is usually 5 or less based on the total number of moles of the monomer constituting (A), although it depends on the polymerizability or reactivity of the crosslinkable monomer (y) used. From the viewpoint of expression of aggregation performance and solubility of the polymer flocculant in water, it is preferably 0.001 to 1, more preferably 0.01 to 0.5.

In the hydrophobic dispersion medium (b) in the present invention, “hydrophobic” means that the solubility in water (g / 100 g of water, 20 ° C.) is less than 1 g.
(B) includes hydrocarbon [aliphatic (C5-12, such as n-hexane, n-heptane, n-octane, n-nonane, n-decane), alicyclic group (C5-12, such as cyclopentane, Cyclohexane, cycloheptane, methylcyclohexane, cyclooctane, decalin) and aromatic ring-containing hydrocarbons (C6-12, such as benzene, toluene, xylene, ethylbenzene), etc.], ketones [aliphatic (C3-10, such as methyl-n-) Propyl ketone, diethyl ketone, methyl isobutyl ketone), alicyclic ring-containing (C5-10, such as cyclopentanone, cyclohexanone) and aromatic ring-containing ketone (C8-13, such as acetophenone, benzophenone), etc.], ether [aliphatic (C4 To 8, for example di-n-propyl ether, di-n-butyl ether , Diethylene glycol dimethyl ether), cyclic ethers (C4-18, eg tetrahydropyrine) and aromatic ring-containing ethers (C7-12, eg anisole)], esters [aliphatic esters (C3-10, eg n-butyl acetate), Alicyclic ring-containing esters (C7-12, such as cyclohexyl acetate, cyclohexanecarboxylate methyl) and aromatic ring-containing esters (C8-13, such as methyl benzoate, ethyl benzoate, n-butyl benzoate, benzyl acetate, dimethyl phthalate, diethyl) Phthalate, di-n-butyl phthalate) and the like, and mixtures thereof.
Of these, from the viewpoint of handling during the production of (A) and temperature control during polymerization, aliphatic and alicyclic hydrocarbons are preferred, and n-hexane, n-heptane, and n-octane are more preferred. , N-nonane, n-decane, cyclohexane and methylcyclohexane.

Examples of the dispersant (c) in the present invention include various oil-soluble substances for the purpose of controlling the particle diameter of the dispersed particles and the later-described angle of repose of the dried particles after the dispersed particles are dehydrated and dried. It is done.
The HLB (Hydrophile-Lipophile Balance) of (c) is preferably 1 to 8 from the viewpoint of controlling the dispersion stability of the reversed-phase suspended particles and the particle size [that is, the angle of repose of the dried particles of (A) described later]. It is preferably 2 to 7, particularly preferably 3 to 5.
Here, HLB represents a balance between hydrophilicity and lipophilicity, and is obtained from the following formula [“Synthesis of surfactants and their applications”, page 501, published by Takashi Shoten in 1957; “New surfactants” [Introduction], pp. 197-198, published by Sanyo Chemical Industries, Ltd. in 1992, etc.].
HLB = 10 × (inorganic / organic)
In the above formula, the value in () represents the inorganic to organic ratio of the organic compound, and the ratio can be calculated from the values described in the above documents.

(C) includes a low molecular dispersant (c1) having a GMw of less than 5,000 (more preferably from 100 to 3,000, particularly preferably from 100 to 1,000), and a GMw of 5,000 or more (more preferably 7,000 to 1,000,000, particularly preferably 10,000 to 100,000) of the polymer dispersant (c2). The (c2) has a glass transition temperature (Tg) of 60 to 100 ° C.

(C1) includes fatty acid (C10-30) esters of polyhydric (2-8 or more) alcohols [sucrose fatty acid esters (C22-120, eg sucrose distearate, sucrose tristearate), sorbitan fatty acid esters (C16-120, eg sorbitan monostearate, sorbitan monooleate), (poly) glycerin fatty acid ester (C12-120, eg glycerin monostearate), PEG fatty acid ester [GMw 100-4,500, eg PEG (GMw 100-4) , 500) monostearate] and the like], alkyl (C1-30) allyl ether and the like.

Of the above (c1), the fatty acid ester of a polyhydric alcohol is preferable from the viewpoint of preventing polymer particle adhesion to the apparatus during the production of (A) and the angle of repose of the dried particles of the polymer flocculant after drying. Preference is given to sucrose fatty acid esters and sorbitan fatty acid esters.

(C2) includes a copolymer of an alkene and an α, β-unsaturated polycarboxylic acid (anhydride) or a derivative thereof [for example, a 1-olefin (C11-100) / (anhydrous) maleic acid copolymer, And its amine reaction product], long-chain alkyl group (C12-50) -containing (meth) acrylate (co) polymer, modified (amino, carboxy, epoxy, hydroxy, mercapto, fatty acid ester or fatty acid amide modified, etc.) organopolysiloxane , Cellulose ether (for example, ethyl cellulose, ethyl hydroxyethyl cellulose), (maleic anhydride modified) ethylene / vinyl acetate copolymer, and the like.
The above (maleic anhydride modified) ethylene / vinyl acetate copolymer is a copolymer of ethylene and / or maleic anhydride modified ethylene and vinyl acetate, and ethylene / vinyl acetate copolymer modified with maleic anhydride. Etc. are included.
Examples of the ethylene / vinyl acetate copolymer modified with maleic anhydride include those obtained by adding maleic anhydride to an ethylene / vinyl acetate copolymer. The weight ratio is preferably 2/98 to 30/70, more preferably 5/95 to 20/80, from the viewpoint of dispersion stability of the reversed-phase suspended particles and adjustment of the molecular weight of the reaction product.
(Maleic anhydride modified) The copolymerization ratio (weight ratio) in the copolymer of ethylene and vinyl acetate is preferably from the viewpoint of solubility in the hydrophobic dispersion medium (b) and dispersion stability of the reversed-phase suspension particles. Is 50/50 to 95/5, more preferably 70/30 to 90/10.

Of the above (c2), from the viewpoints of preventing adhesion of polymer particles to the apparatus during the production of (A) and the angle of repose of the dried particles of the polymer flocculant after drying, alkene and α, β-unsaturation are preferable. A copolymer with a polyvalent carboxylic acid (anhydride) or a derivative thereof, a modified organopolysiloxane, and a (maleic anhydride-modified) ethylene / vinyl acetate copolymer.

The dispersant (c) is preferably 60 to 100 ° C., more preferably from the viewpoint of powder flowability of the water-soluble (co) polymer (A) and solubility in the hydrophobic dispersion medium (b) during polymerization. It is preferable to contain a dispersant [for example, the above (c2)] having a Tg of 65 to 95 ° C., particularly preferably 67 to 92 ° C., and most preferably 70 to 90 ° C. The Tg is measured using a differential scanning calorimeter (DSC) according to the method for measuring the transition temperature of JIS K7121-1987 plastic.

The melting point of (c) is preferably 25 to 100 ° C. from the viewpoint of powder flowability of the water-soluble (co) polymer (A) and solubility in the hydrophobic dispersion medium (b) at the time of polymerization. The temperature is preferably 30 to 80 ° C, particularly preferably 40 to 70 ° C. The melting point is measured using a melting point measuring device according to JIS K0064-1992, 3.2 melting point test method.

In using the dispersant (c), it is preferable to use (c1) and (c2) in combination from the viewpoints of dispersion stability of reversed-phase suspended particles, angle of repose of dry particles, and particle size distribution. The ratio [(c1) / (c2)] is preferably 70/30 to 1/99, more preferably 50/50 to 5/95, from the same viewpoint.
When (c1) and (c2) are used in combination, a preferred combination from the viewpoint of the particle size distribution of the dry particles is a combination of a fatty acid ester of a polyhydric alcohol and a maleic anhydride-modified ethylene / vinyl acetate copolymer, more preferably PEG. A combination of a fatty acid ester and a maleic anhydride-modified ethylene / vinyl acetate copolymer.

The amount of (c) used is based on the weight of the hydrophobic dispersion medium (b), the stability of the reversed-phase suspension particles, the prevention of polymer particle adhesion to the apparatus during polymerization, and the rest of the dry particles of the polymer flocculant From the viewpoint of controlling the angle and particle diameter, it is preferably 0.01 to 20%, more preferably 0.03 to 10%, and particularly preferably 0.05 to 5%.

Examples of the polymerization initiator (d) include various compounds such as azo compounds [water-soluble compounds [azobisamidinopropane (salt), azobiscyanovaleric acid (salt), etc.]) and oil-soluble compounds [azobiscyanovalero]. Nitriles, azobisisobutyronitrile, azobiscyclohexanecarbonitrile, etc.]] and peroxides [water-soluble [peracetic acid, t-butyl peroxide, hydrogen peroxide, ammonium persulfate, sodium persulfate, potassium persulfate] Etc.] and oil-soluble ones [benzoyl peroxide, cumene hydroxy peroxide, etc.].
Examples of the salt in the azo compound include inorganic acid (hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, etc.) salts, alkali metal (lithium, sodium, potassium, etc.) salts, ammonium salts, and the like.
The above peroxide may be used as a redox initiator in combination with a reducing agent. Examples of the reducing agent include bisulfites (sodium bisulfite, potassium bisulfite, ammonium bisulfite, etc.), reducing metal salts [iron sulfate (II ), Etc.], amine complexes of transition metal salts [pentamethylenehexamine complexes of cobalt (III) chloride, diethylenetriamine complexes of copper (II) chloride, etc.], organic reducing agents [ascorbic acid, tertiary amine [dimethylaminobenzoic acid ( Salt), dimethylaminoethanol and the like].
Further, the azo compound, peroxide and redox initiator may be used alone or in combination of two or more.
(D) is usually present in the monomer aqueous solution (hereinafter sometimes referred to as a dispersed phase), but may also be present in a hydrophobic dispersion medium.

The amount of (d) used is preferably 0.001 to 1%, more preferably 0.005 to 0.00, based on the total weight of the monomers constituting (A) from the viewpoint of obtaining an optimum molecular weight. 5%, particularly preferably 0.01 to 0.1%, most preferably 0.02 to 0.05%.

In the reverse phase suspension polymerization in the present invention, a chain transfer agent (f) may be used if necessary. Examples of (f) include compounds having one or more OH groups in the molecule [monohydric alcohol (C1-60, such as methanol, ethanol, n- and i-propanol), polyvalent (2 to 3 or more) alcohol (C2-60, eg EG, PG), polymeric polyol (GMn 200-10,000, eg PEG, oxyethylene / oxypropylene block and / or random copolymer), 1 in the molecule Compounds having one or more amino groups [C0-60, such as ammonia, methylamine, dimethylamine, triethylamine, n- and i-propanolamine], hypophosphites (such as sodium hypophosphite), Examples thereof include compounds having one or more thiol groups in the molecule (described later).
Of these, compounds having one or more thiol groups in the molecule are preferred from the viewpoint of molecular weight control.

Examples of the compound having one or more thiol groups in the molecule include the following compounds, salts thereof [alkali metal salts, alkaline earth metal salts, ammonium salts, amines (C1-20, such as methylamine, ethanol Amine) salts, inorganic acid (hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, etc.) salts, and the like], and mixtures thereof.
(1) Monovalent thiol Aliphatic thiol (C1-20, such as methanethiol, ethanethiol, propanethiol, n-octanethiol, n-dodecanethiol, hexadecanethiol, n-octadecanethiol, 2-mercaptoethanol, mercaptoacetic acid, 3-mercaptopropionic acid, 1-thioglycerol, thioglycolic acid monoethanolamine, thiomaleic acid, mercaptosuccinic acid, cysteine, cysteamine), alicyclic thiol (C5-20, eg cyclopentanethiol, cyclohexanethiol), aromatic ring Containing thiols (C6-12, such as benzenethiol, thiosalicylic acid, thiocresol, thiolenol, thionaphthol) and araliphatic thiols (C7-20, such as α-toluenethiol). It is.

(2) Polyvalent thiol dithiol [aliphatic dithiol (C2-40, such as ethanedithiol, diethylenedithiol, triethylenedithiol, n-, i- and sec-propanedithiol, 1,3- and 1,4-butanedithiol, 1,6-hexanedithiol, neopentanedithiol), alicyclic dithiols (C5-20, eg cyclopentanedithiol, cyclohexanedithiol), aromatic dithiols (C6-16, eg benzenedithiol, biphenyldithiol) and araliphatic dithiols (C8-20, such as xylenedithiol).

The use amount of (f) is preferably 0.0001 based on the total weight of (a), (x) and (y) from the viewpoint of obtaining the optimum molecular weight of the polymer flocculant of the present invention. %, More preferably 0.001%, particularly preferably 0.01%, most preferably 0.05%, the preferred upper limit is 10%, more preferably 5%, particularly preferably 3%, most preferably 1%. is there.

The monomer content (hereinafter sometimes referred to as monomer concentration) in the aqueous monomer solution (dispersed phase) in the present invention is determined based on the weight of the aqueous monomer solution, productivity and dispersion stability, and a water-soluble (co) polymer. From the viewpoint of reducing the water-insoluble content of (A), it is preferably 40 to 80%, more preferably 45 to 75%, particularly preferably 48 to 72%, and most preferably 50 to 70%.

The pH of the aqueous monomer solution in the present invention is preferably 2 to 8, more preferably 2.5 to 7, particularly preferably 3 to 6.5, from the viewpoints of increasing the molecular weight and preventing hydrolysis of (A).
pH adjusters used for pH adjustment include inorganic acids (sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid, etc.) and inorganic solid acidic substances (acidic sodium phosphate, acidic sodium nitrate, ammonium chloride) when the aqueous monomer solution is alkaline. , Ammonium sulfate, ammonium bisulfate, sulfamic acid, etc.) and organic acids (C2-20, such as oxalic acid, succinic acid, malic acid). When the aqueous monomer solution is acidic, inorganic alkaline substances (sodium hydroxide, potassium hydroxide) , Ammonia and the like) and organic alkaline substances (guanidine and the like).
Here, the pH is a value measured at room temperature (20 ° C.) using a stock solution of the monomer aqueous solution using a pH meter [eg, trade name “LAB pH meter M-12”, manufactured by Horiba, Ltd.].

Examples of the reverse phase suspension polymerization method in the present invention include the following methods. That is, the hydrophobic dispersion medium (b) and the dispersing agent (c) are charged into a polymerization tank to obtain a mixed liquid, adjusted to a predetermined polymerization temperature while heating as necessary, and then the inside of the tank is filled with an inert gas (for example, nitrogen ). On the other hand, an aqueous monomer solution containing a water-soluble unsaturated monomer (a), a polymerization initiator (d), and, if necessary, a water-insoluble unsaturated monomer (x) and / or a crosslinkable monomer (y) is prepared, and an inert gas After sufficiently substituting with, the mixture is put into a polymerization tank under stirring and polymerized while being suspended.

The monomer aqueous solution is added dropwise. Examples of the dropping method include the following.
(1) A uniform aqueous solution of (a) and (d) is added dropwise.
(2) The aqueous solution of (a) and (d) or the aqueous solution thereof are added dropwise with continuous mixing immediately before the addition.
(3) The aqueous solution of (a) and the aqueous solution of (d) are simultaneously dropped simultaneously.
Among these, (2) is preferable from the viewpoint of reducing the water-insoluble content and reducing the molecular weight distribution (A) described later.
In mixing the monomer aqueous solution and (d), the temperature of the monomer aqueous solution is usually 25 ° C. or less, and preferably 10 to 20 ° C. from the viewpoint of polymerization rate and reduction of water insoluble matter.
Examples of the method for substituting the monomer aqueous solution with the inert gas include a method for bubbling and supplying the inert gas to the monomer aqueous solution and the like, a method for blending the monomer aqueous solution and the inert gas with a static mixer or the like in the dropping line, and the like. Among these, a blending method using a static mixer or the like is preferable from the viewpoint of reducing water-insoluble matter.

The volume average diameter of the droplet when the monomer aqueous solution is dropped is preferably 0 from the viewpoints of the solubility characteristics of (A) and the reduction of water-insoluble matter and the content of the hydrophobic solvent (b) in the polymer flocculant. 0.1 to 3 mm, more preferably 0.15 to 2.5 mm, particularly preferably 0.2 to 2 mm, and most preferably 0.5 to 1.5 mm. The volume average diameter is measured by using an image analysis software [for example, the trade name “VK” with a high-speed camera [for example, trade name “Motion Analysis Microscope VW-6000”, manufactured by Keyence Corporation]. -H1A7 "(manufactured by Keyence Co., Ltd.)] was included, and this method was followed in the examples described later.

The polymerization temperature of the reversed phase suspension polymerization is preferably 70 ° C. or less, more preferably 10 to 70 from the viewpoint of the polymerization rate and the stability of the reversed phase suspension particles, the high molecular weight of (A), and the reduction of water insoluble matter. ° C, more preferably 20-60 ° C, particularly preferably 30-55 ° C, most preferably 40-50 ° C.
Further, during the polymerization, it is preferable to appropriately heat and cool, or to adjust the dropping speed of the aqueous monomer solution so that the predetermined polymerization temperature is kept constant (for example, the predetermined polymerization temperature ± 5 ° C.).

Polymerization pressure [kPa (absolute pressure), only numerical values are shown below. ] Is preferably reduced pressure conditions from the viewpoint of controlling the fractal order of the polymer flocculant particles and preventing the polymer particles from adhering to the apparatus during polymerization, and the pressure is preferably 10 or more and less than 101.3, more preferably 30 to 100 Particularly preferred is 50 to 90. The fractal order of the polymer flocculant particles can be reduced as the pressure during polymerization is lower (that is, the degree of pressure reduction is higher). Further, vacuum boiling polymerization, which is carried out under reduced pressure conditions and at the boiling point of (b), is also preferred from the viewpoint of narrowing the molecular weight distribution.

The completion of the polymerization reaction can be confirmed when the exotherm due to the polymerization disappears, but the polymerization time is usually 1 to 24 hours from the time when the initiation of the polymerization is confirmed by the usual exotherm, the completion of the polymerization, the reduction of residual monomers, and an industrial viewpoint. To preferably 2 to 12 hours, more preferably 3 to 10 hours.
The monomer concentration, polymerization temperature, and polymerization time can be appropriately adjusted depending on the monomer composition, initiator type, and the like.

Further, the water-soluble (co) polymer (A) in the present invention may be further modified. As the polymer modification method, for example, when acrylamide having a hydrolyzable functional group in the molecule is used as the water-soluble unsaturated monomer (a), a caustic alkali (sodium hydroxide, potassium hydroxide, etc.) during or after polymerization Alternatively, a method of adding an alkali carbonate (sodium carbonate, potassium carbonate, etc.) and partially hydrolyzing the amide group of (a) to introduce a carboxyl group (JP-A No. 56-16505 etc.); formaldehyde, A method in which dialkylamine (C1-12) and halogenated (chlorine, bromine, iodine, etc.) alkyl (C1-12) (methyl chloride, ethyl chloride, etc.) are added, and a cationic group is partially introduced by Mannich reaction; acrylonitrile Nitrile groups such as, and amino groups obtained by hydrolysis of vinylformamide, etc. A method of forming an amidine ring in the molecule by a ring-closing reaction of JP-A No. 5-192513; and a method of adding the cross-linkable monomer (y) after polymerization to cause a cross-linking reaction (Japanese Patent No. 3305688) Etc.

The intrinsic viscosity [η] of the water-soluble (co) polymer (A) (measured in a 1N-NaNO ₃ aqueous solution at 30 ° C., the unit is dl / g. The same shall apply hereinafter) is usually 1 to 40, aggregation performance and aggregation From the viewpoint of speed, it is preferably 2 to 38, more preferably 4 to 35, and most preferably 5 to 30.

The weight average molecular weight (Mw) of (A) in the present invention is obtained by conversion from the intrinsic viscosity [η], and the viscosity formula of the polyacrylamide polymer: [η] = 3.73 × 10 −4 × (Mw) × 0.66 [Radical Polymerization Handbook, published by NTS, 558 (1999)] can be used to determine (Mw). According to the viscosity equation, (A) can be determined not only for nonionic polyacrylamide but also for cationic, anionic and amphoteric polymers.

The number average molecular weight (Mn) of (A) is determined by the osmotic pressure method. The measurement method is measured under the following conditions.
The osmotic pressure measurement method includes a membrane type osmotic pressure measurement method. In the membrane type osmotic pressure measurement method, Mn is obtained as follows. That is, in the case of an ideal solution, from the van thoff's formula: πV = wRT / M (π: osmotic pressure, V: volume, w: mass, R: gas constant, T: absolute temperature, M: number average molecular weight) C _{Substituting m} (volume molar concentration) = w / (MV) yields π = C _m RT. Here, when a high molecular weight material such as (A) in the present invention is measured, it is necessary to correct, and from the correction formula π = C _m RT + αC _m ² , π / C _m = RT + αC _m . (Α: constant independent of concentration)
Here, when the concentration C is expressed in g per capacity, it is only necessary to substitute C _m = C / M, so that the above equation becomes π / C = RT / M + (α / M ² ) C.
By measuring the osmotic pressure by changing the concentration, if C and π / C are plotted on the graph as the X axis and Y axis, respectively, and the point where the extension line crosses the Y axis (π / C) is obtained, Since the height corresponds to RT / M, M of (A) in the infinitely diluted solution, that is, Mn in the present invention can be obtained therefrom. Usually, the measurement temperature is 37 ° C., and the gas constant R is 8.31 Pa · m ³ / mol · K.

The molecular weight distribution of (A) in the present invention is represented by the (Mw / Mn) ratio, and is preferably 1 to 30, more preferably 2 to 28, particularly preferably 5 to 25, and most preferably 10 from the viewpoint of aggregation performance. ~ 20.
As for the (Mw / Mn) ratio, the intrinsic viscosity [η] is in the range of 1 to 40 or the preferable [η], and the (Mw / Mn) ratio is in the above range. It is preferable from the viewpoint of performance.

(Mw / Mn) of (A) is dropped while continuously mixing the monomer aqueous solution at 10 to 20 ° C. and the polymerization initiator (d) immediately before dropping the monomer aqueous solution into the hydrophobic solvent (b). It can be reduced by controlling the polymerization temperature and drying temperature in a narrow temperature range, keeping the monomer concentration at the time of polymerization constant at an appropriate concentration, etc., and making it (Mw / Mn) within the above range it can.

The water-soluble (co) polymer (A) is obtained in the state of hydrogel particles in the hydrophobic solvent (b) immediately after production, and (1) a method of drying the solid content after solid-liquid separation, Alternatively, (2) the polymer flocculant of the present invention in the form of solid particles is obtained by a method in which the hydrophobic dispersion medium (b) and water are azeotropically dehydrated under reduced pressure to form a slurry, and the solid content is dried after solid-liquid separation. be able to.
Examples of the drying method include hot air drying, infrared drying, indirect heating drying (vacuum drying, drying using a stirring dryer, drying with a drum dryer) and the like.
Of the above methods (1) and (2), the method (2) is preferable from the viewpoint of preventing crosslinking by local heating, and the drying method is preferably vacuum drying from the same viewpoint.
The drying temperature (° C.) is usually 20 to 200, preferably 30 to 150, more preferably 40 to 120 from the viewpoint of drying speed and crosslinking prevention.

[Polymer flocculant]
The polymer flocculant of the present invention contains dry particles of the water-soluble (co) polymer (A), and the particles contain secondary particles obtained by combining single particles (primary particles). .
The secondary particles include the following (1) to (3) and mixtures thereof. Here, “composite” means that a plurality of primary particles are bonded together, or the bonded particles are further bonded together.
(1) A plurality of primary particles of the same size are joined together to form a bead or grape bunch.
(2) A plurality of relatively small primary particles are bonded to the surface of relatively large primary particles, and at least a part of the surface is coated.
(3) The above (1) are further joined together.
(4) The above (2) are further joined together.
(5) The above (1) and (2) are further joined together.

Examples of a method of forming secondary particles by combining the primary particles include the following [1] to [3] and combinations thereof. Among these, the method [1] is preferable from the viewpoint of productivity.
[1] A method of forming secondary particles by fusing primary particles together by raising the temperature of the reaction system to 50 to 100 ° C. to the melting point of the dispersant (c) or higher after the polymerization reaction is completed. .
[2] A method of forming secondary particles by spraying water onto the water-containing gel particles and fusing the primary particles together in the solid-liquid separation step of (b) after the polymerization reaction and the water-containing gel particles.
[3] A method of forming secondary particles by coalescing primary particles by spraying water in the drying step after the solid-liquid separation step.

The content of secondary particles in the dry particles (A) in the polymer flocculant of the present invention is preferably 1 to 100% by weight, more preferably 5 to 80% from the viewpoints of dissolution characteristics and appropriate powder flowability. % By weight. By combining the primary particles to form secondary particles [1] to [3] and using them together, the content of the secondary particles in the dry particles can be within the above range. The content of the secondary particles can be measured by the method described later.

The volume average particle diameter (μm) of the primary particles in the present invention is preferably 10 to 1,000, and more preferably 50 to 500, from the viewpoint of appropriate powder flowability and narrow molecular weight distribution.
The volume average particle diameter (μm) of the secondary particles is preferably from 150 to 3,000, more preferably from 200 to 2,500, and particularly preferably from 250 to 2,000, from the viewpoints of dissolution characteristics and appropriate powder fluidity. It is. Here, the volume average particle diameter can be measured using, for example, [Microtrac MT3000II particle size analyzer], manufactured by Nikkiso Co., Ltd.

The angle of repose of the polymer flocculant of the present invention (hereinafter sometimes referred to as polymer flocculant particles) is preferably from the viewpoint of appropriate powder flowability suitable for stable quantitative supply with the automatic metering device. It is 25 to 45 degrees, more preferably 30 to 43 degrees.
The polymer flocculant of this invention can make an angle of repose into the said range by performing reverse phase suspension polymerization using the dispersing agent (c) which has specific HLB as above-mentioned.
Here, the angle of repose is a value obtained by the cylindrical rotation method, and the upper limit inclination angle with respect to the horizontal plane when the granular container is slowly rotated to form a stable inclined surface. It can be measured using a three-wheeled angle of repose measuring machine [manufactured by Tsutsui Rika Instruments Co., Ltd.].

The fractal order of the polymer flocculant particles of the present invention is 1.2 to 1.9, preferably 1.3 to 1.85, more preferably 1.4 to 1.8, particularly preferably 1.5 to 1. .7. When the fractal order is less than 1.2, the powder fluidity is deteriorated, and when it exceeds 1.9, the solubility in water is deteriorated.
From the viewpoint of setting the fractal order of the polymer flocculant particles of the present invention in the above range, it is preferable to increase the content of secondary particles.
Here, the fractal order is an index representing the shape of the particle, that is, the unevenness of the particle surface. A small fractal order means that the surface of the surface of the primary particle or the secondary particle combined with the primary particle is large and the surface area is large. Means. The fractal order is 2 if the surface of the particle is a perfect sphere or ellipsoid having no irregularities.

The fractal order can be measured by the following method described in JP-A-2001-2935.
<Fractal order measurement method>
One polymer flocculant particle taken at random at 25, 30, 50 and 100 times using a scanning electron microscope [for example, “JSM-7000F” manufactured by JEOL Datum Co., Ltd.] Take a photo of For each of these photographs, the particle contour length (L) and the particle projected area (S) are obtained by using image analysis software “WinROOF” [trade name, manufactured by Mitani Corporation]. Next, the common logarithm of (L) and (S) of each photograph is obtained. The obtained values are plotted on an XY coordinate diagram in which the common logarithm of (L) is the X axis and the common logarithm of (S) is the Y axis, and a straight line is drawn by the method of least squares. The above straight line is drawn in the same manner for each of the four particles of the polymer flocculant taken out at random, and the five simple average values of the slopes are taken as the fractal order.

The content (% by weight) of the hydrophobic dispersion medium (b) remaining in the polymer flocculant particles of the present invention is usually 5% or less, preferably 4% or less from the viewpoint of the solubility of the polymer flocculant, Preferably it is 2% or less, particularly preferably 1% or less.

The content of (b) remaining in the polymer flocculant particles is such that the droplet diameter (mm) when the monomer aqueous solution is dropped into (b) during the production of (A) is within the above range. By setting the HLB of the dispersant (c) within the above range, the above range can be obtained. The content of (b) can be measured by the method described later.

The content (% by weight) of the dispersant (c) remaining in the polymer flocculant particles of the present invention is preferably 0.01 from the viewpoint of powder flowability and water solubility of the polymer flocculant particles. -1%, more preferably 0.02-0.5%, particularly preferably 0.03-0.2%, most preferably 0.05-0.1%.

The content of (c) remaining in the polymer flocculant particles is set to the above range by setting the Tg and melting point of (c) within the above range, the use amount of (c) within the above range, and the like. be able to.

The water-insoluble content (% by weight) in the polymer flocculant of the present invention is usually 5% or less, preferably 3% or less, more preferably 2% or less, particularly preferably 1% or less from the viewpoint of aggregation performance. . The water-insoluble matter can be measured by the method described later.

Among the application targets of polymer flocculants, in sewage sludge, the size of suspended particles is relatively large and the surface of suspended particles in water has a negative charge. Preferred are cationic or amphoteric polymer flocculants and mixtures thereof.
In wastewater, an inorganic flocculant is often added to treat soluble organic matter, and in that case, since the suspended particle surface is covered with the inorganic flocculant, it has a positive charge. For the coagulation precipitation treatment, an anionic or nonionic polymer flocculant and a mixture thereof are preferable.
As the polymer flocculant for the third recovery of petroleum, those having a relatively large molecular weight are used, and anionic or nonionic and mixtures thereof are preferable.
In addition, a cationic or amphoteric polymer flocculant and a mixture thereof are preferable for improving the drainage yield or enhancing the paper strength in the papermaking process.

Here, the cationic polymer flocculant is a polymer flocculant having a cationic group in the molecule, that is, a polymer flocculant exhibiting a cationic property when dissolved in water, and an amphoteric polymer flocculant and Is a polymer flocculant having a cationic group and an anionic group in the molecule, that is, a polymer flocculant exhibiting cationic and anionic properties when dissolved in water.
The cationic or anionic property of these polymer flocculants in water can be evaluated by a colloid equivalent value (meq / g). That is, the cationic group equivalent value in the cationic flocculant can be determined as the cation colloid equivalent value, and the cationic group equivalent value and the anionic group equivalent value in the amphoteric flocculant are the cationic colloid equivalent value and the anionic colloid respectively. It can be determined as an equivalent value.

When the polymer flocculant of the present invention is a cationic polymer flocculant, the cation colloid equivalent value (meq / g) in the flocculant is preferably 0.1 to 7, more preferably 0 from the viewpoint of the aggregation performance. 0.5 to 6, more preferably 1 to 5.5, particularly preferably 1.5 to 5.2, and most preferably 2 to 5.
When the polymer flocculant of the present invention is an amphoteric polymer flocculant, the cation colloid equivalent value (meq / g) in the flocculant is preferably from 0.1 to 7, more preferably from the viewpoint of aggregation performance. 0.5-6, more preferably 1-5.5, particularly preferably 1.5-5.2, most preferably 2-5; anionic colloid equivalent value (meq / g) is preferred from the viewpoint of aggregation performance Is -13 to -0.05, more preferably -10 to -0.1, still more preferably -8 to -0.3, particularly preferably -5 to -0.5, most preferably -3 to -1. It is.

The colloid equivalent value can be determined by the colloid titration method shown below. The subsequent measurement is performed at room temperature (about 20 ° C.).
(1) Preparation of measurement sample (50 ppm aqueous solution of polymer flocculant) Weigh accurately 0.2 g of sample (in terms of solid content), put it in a 200 ml Erlenmeyer flask, and total weight (total of sample and ion-exchanged water) After adding ion-exchanged water so that the weight is 100 g, a magnetic stirrer (40 mm long, 5 mm diameter cylindrical magnet, the same shall apply hereinafter, rotation speed 1,000 rpm) is stirred for 3 hours to completely dissolve. To prepare a 0.2% by weight polymer flocculant solution. Take 10 ml of the prepared solution in a 500 ml beaker, add ion exchange water so that the total weight (total weight of solution 10 ml and ion exchange water) is 400 g, and again magnetic stirrer (1,000 to 1,200 rpm) Then, stir for 30 minutes to obtain a uniform measurement sample.
The solid content of the polymer flocculant was weighed (W1) in a petri dish (diameter: 100 mm, depth: 10 mm) and dried at 105 ± 5 ° C. for 90 minutes in a circulating drier. This is a value calculated from the following equation based on the remaining weight (W2).
Solid content (% by weight) = (W2) × 100 / (W1)

(2) Measurement of cation colloid equivalent value 100 g of the measurement sample obtained in (1) was placed in a 200 ml conical beaker and gradually added with a 0.5 wt% aqueous sulfuric acid solution while stirring with a magnetic stirrer (500 rpm). adjust. Then add 2-3 drops of toluidine blue indicator (TB indicator) and titrate with N / 400 potassium potassium sulfate (N / 400 PVSK) reagent. The titration rate is 2 ml / min, and the end point is the time when the measurement sample changes color from blue to reddish purple and the reddish purple color is maintained for 30 seconds.

(3) Measurement of anion colloid equivalent value 100 g of a measurement sample was placed in a 200 ml conical beaker, 0.5 ml of an N / 10 sodium hydroxide aqueous solution was added while stirring with a magnetic stirrer (500 rpm), and further N / 200 methyl glycol chitosan. After adding 5 ml of an aqueous solution, the mixture is stirred for 5 minutes (pH about 10.5 at that time). Add 2-3 drops of TB indicator and titrate in the same manner as in (2) above.
(4) Blank test The same operation as (2) and (3) is performed except that 100 g of ion-exchanged water is used instead of the measurement sample.
(5) Calculation Method Cation or Anion Colloid Equivalent Value (meq / g) = (1/2) × (Titration of Measurement Sample−Titration of Blank Test) × [Titer of (N / 400 PVSK)]

The polymer flocculant of the present invention is an antifoaming agent (B1), a chelating agent (B2), a pH adjusting agent (B3), a surfactant (B4), as long as it does not inhibit the effects of the present invention. An additive (B) selected from the group consisting of an antiblocking agent (B5), an antioxidant (B6), an ultraviolet absorber (B7) and a preservative (B8) can be used in combination.

Examples of the antifoaming agent (B1) include silicone compounds [GMn 100 to 100,000, such as dimethylpolysiloxane], mineral oil (spindle oil, kerosene, etc.), metal soap (C12-22, such as calcium stearate) and the like;
Examples of the chelating agent (B2) include aminocarboxylic acids (C6-24, such as ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, hydroxyethylethylenediaminetriacetic acid, nitrilotriacetic acid, triethylenetetraminehexaacetic acid), polyvalent carboxylic acids [C4 or more and GMn 10,000 or less, such as maleic acid, polyacrylic acid (GMn 1,000-10,000) and isoamylene / maleic acid copolymer (GMn 1,000-10,000)], hydroxycarboxylic acids (C3-10, such as Acid, gluconic acid, lactic acid, malic acid), condensed phosphoric acid (tripolyphosphoric acid, trimetaphosphoric acid, etc.), and salts thereof [metal (alkali metal, alkaline earth metal, etc.) salt, ammonium salt, alkylamine (C1-20) For example, methylamino , Ethylamine, octylamine) salt and alkanolamine (C2 ~ 12, for example mono-, - di - and triethanolamine) salts], and the like;

Examples of pH adjusters (B3) include caustic alkalis (caustic soda, caustic potash, etc.), amines (C1-20, such as methylamine, ethylamine, mono-, di- and triethanolamine), inorganic acids (salts) [inorganic acids ( Hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, sulfamic acid, carbonic acid, etc.) and their metal (same as above) salts (sodium carbonate, potassium carbonate, sodium sulfate, sodium hydrogen sulfate, monosodium phosphate, etc.) and ammonium salts ( Ammonic carbonate, ammonium sulfate, etc.)], organic acid (salt) [organic acid [carboxylic acid (C2-15, such as acetic acid, citric acid), sulfonic acid (C1-15, such as methanesulfonic acid, ethanesulfonic acid, p -Toluenesulfonic acid) and phenol] and their metal (same as above) salts (sodium acetate, sodium lactate) Etc. etc.) and ammonium salts (ammonium acetate, etc. ammonium lactate) and the like];

Surfactants (B4) include surfactants described in US Pat. No. 4,331,447, such as polyoxyethylene nonylphenyl ether and dioctylsulfosuccinate soda; antiblocking agents (B5) include polyether-modified silicone oil ( GMn 100-3,000), for example polyoxyethylene modified silicone and polyoxyethylene / polyoxypropylene modified silicone];

Antioxidants (B6) include phenol compounds [hydroquinone, methoxyhydroquinone, catechol, 2,6-di-t-butyl-p-cresol (BHT) and 2,2′-methylenebis (4-methyl-6-t -Butylphenol), etc.], sulfur-containing compounds [thiourea, tetramethylthiuram disulfide, dimethyldithiocarbamic acid and its salts [eg, metal (same as above) salts and ammonium salts, etc.], sodium sulfite, sodium thiosulfate, 2-mercapto Benzothiazole and its salts (same as above), dilauryl 3,3′-thiodipropionate (DLTDP) and distearyl 3,3′-thiodipropionate (DSTDP), etc.], phosphorus-containing compounds [triphenyl phosphite , Triethyl phosphite, sodium phosphite , Sodium hypophosphite, triphenyl phosphite (TPP) and triisodecyl phosphite (TDP) and the like] and nitrogen-containing compounds [amines (octylated diphenylamine, Nn-butyl-p-aminophenol and N, N-diisopropyl-p-phenylenediamine, etc.), urea, guanidine and guanidine inorganic acid (same as above) salts], etc .;

Examples of the ultraviolet absorber (B7) include benzophenone compounds (2-hydroxybenzophenone, 2,4-dihydroxybenzophenone, etc.), salicylate compounds (phenyl salicylate, 2,4-di-t-butylphenyl-3,5-di). -T-butyl-4-hydroxybenzoate etc.), benzotriazole compounds [(2'-hydroxyphenyl) benzotriazole, (2'-hydroxy-5'-methylphenyl) benzotriazole etc.] and acrylate [ethyl-2-cyano −3,3-diphenyl acrylate, methyl-2-carbomethoxy-3- (paramethoxybenzyl) acrylate, etc.] etc .;
Examples of the preservative (B8) include benzoic acid, paraoxybenzoic acid ester, and sorbic acid.

The above (B) may be added in advance to the monomer aqueous solution before polymerization or may be added to the polymer after production. The total amount of (B) used is usually 30% or less based on the weight of the monomer or polymer, and preferably 0 to 10% from the viewpoint of aggregation performance.
The use amount of each additive of (B1) to (B8) is usually 5% or less, preferably 1 to 3%, and (B2) is usually 20% or less based on the same weight as above. Preferably 2 to 10%, (B3) is usually 10% or less, preferably 1 to 5%, (B4) and (B5) are each usually 5% or less, preferably 1 to 3%, (B6), (B7 ) And (B8) are each usually 5% or less, preferably 0.1 to 2%.

Examples of the method for adding the polymer flocculant of the present invention to sewage sludge and the like include the methods described in Japanese Patent No. 1311340 or Japanese Patent No. 2038341.
The amount of the polymer flocculant used in the present invention varies depending on the type of sewage sludge, the content of suspended particles, the molecular weight of the polymer flocculant, etc., but the weight of evaporation residue in the sewage sludge etc. Based on the abbreviation), it is usually 0.01 to 10%, preferably from 0.1 to 5%, more preferably from 0.5 to 3%, particularly preferably from 1 to 2% from the viewpoint of aggregation performance and industry. .

As a method of using the polymer flocculant of the present invention, it is preferable to add it to sewage sludge after making it into an aqueous solution from the viewpoint of sufficient flocculation performance, but the polymer flocculant is added directly to sewage sludge etc. in a solid state. You can also
The concentration when the polymer flocculant is used as an aqueous solution is preferably 0.05 to 1% by weight from the viewpoint of handling and dissolution rate.
As a method for dissolving the polymer flocculant, for example, a predetermined amount of the polymer flocculant is gradually added while stirring the water weighed in advance using a stirring device such as a jar tester, and several hours (about 2 to 4 hours). A method of dissolving by applying a degree) can be employed. When the powdery polymer flocculant is dissolved in water, a method of adding a predetermined amount of the polymer flocculant at a stretch is undesirably caused by the fact that it becomes difficult to completely dissolve in water.

When the polymer flocculant of the present invention is used for the third recovery of petroleum, it is usually used as an aqueous solution. The concentration (% by weight) of the aqueous polymer solution is preferably from 0.001 to 3%, more preferably from 0.005 to 1%, particularly preferably from 0.01 to 0, from the viewpoints of thickening effect and viscosity capable of being fed. .5%.

When the polymer flocculant of the present invention is applied to sewage sludge, etc., if the sewage sludge is organic sludge or anaerobic bacteria-treated sludge, inorganic and / or organic coagulation is performed from the viewpoint of charge neutralization of sludge particles. It is preferable to use an agent in combination.
Inorganic coagulants include sulfate band, polyaluminum chloride, ferric chloride, ferric sulfate, polyiron sulfate (polyferric sulfate, etc.), slaked lime, etc .; organic coagulants include aniline-formaldehyde polycondensate Hydrochloride, polyvinylbenzyltrimethylammonium chloride, dimethyldi (meth) allylammonium chloride, (meth) allylamine or di (meth) allylamine-maleic acid copolymer, (meth) allylamine or di (meth) allylamine-citraconic acid copolymer (Meth) allylamine or di (meth) allylamine-itaconic acid, (meth) allylamine or di (meth) allylamine-fumaric acid copolymer, and the like.
When an inorganic and / or organic coagulant is used in combination, sewage sludge is treated with a mixture obtained by adding these to the polymer flocculant of the present invention in advance, or an inorganic coagulant and / or an organic coagulant is preliminarily applied to the sewage sludge. After the primary agglomeration is added, the polymer aggregating agent of the present invention may be added and processed, but the latter method is preferred from the viewpoint of floc strength.

The amount used when using an inorganic coagulant and / or an organic coagulant varies depending on the type of sewage sludge, the size of suspended particles, the type of coagulant used, etc., but based on the TS in the sewage sludge. 20% or less for inorganic coagulants, preferably 0.5 to 10%, more preferably 1 to 5%, particularly preferably 1.5 to 3% from the viewpoint of coagulation performance; usually 1% or less for organic coagulants From the viewpoint of setting performance, it is preferably 0.01 to 0.5%, more preferably 0.025 to 0.2%, and particularly preferably 0.05 to 0.15%.

When the polymer flocculant of the present invention is added, the pH of sewage sludge and the like may be adjusted in advance. The pH adjustment range is usually from 3 to 8, preferably from 3.5 to 7, more preferably from 4 to 6, particularly preferably from 4.5 to 5.5 from the viewpoint of hydrolysis prevention and solubility of the polymer flocculant. is there.
Examples of the pH adjusting method include a method using an acidic substance such as an inorganic acid (sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid, etc.) or an alkaline substance such as a caustic alkali (sodium hydroxide, potassium hydroxide, etc.). In addition, the pH can be adjusted by adding the inorganic or organic coagulant to sewage sludge or the like in advance.

Further, as a dehydration method (solid-liquid separation method) for floc formed by adding the polymer flocculant of the present invention to sewage sludge, various methods such as centrifugal dehydration, belt press dehydration, filter press dehydration, and capillary dehydration are available. Dehydration method can be applied. Among these, centrifugal dehydration, belt press dehydration, and filter press dehydration are preferable from the viewpoint of high floc strength, which is the specific aggregation performance of the polymer flocculant of the present invention.

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples. In addition, the part in an Example represents a weight part and% represents weight%.

The composition and symbols of the raw materials used in Examples and Comparative Examples are as follows.
(1) Water-soluble unsaturated monomer (a)
DAMQ: 80% aqueous solution of methyl chloride salt of N, N-dimethylaminoethyl methacrylate DAAQ: 80% aqueous solution of methyl chloride salt of N, N-dimethylaminoethyl acrylate AAM: 50% aqueous solution of acrylamide AAC: Acrylic acid (2 ) Chain transfer agent (f)
(F-1): 1% aqueous solution of 1-thioglycerol (f-2): 1% aqueous solution of mercaptoacetic acid (f-3): 1% aqueous solution of cysteamine hydrochloride (3) polymerization initiator (d)
(D-1): Dicumyl peroxide
(D-2): 10% aqueous solution of azobisamidinopropane hydrochloride

(4) Hydrophobic dispersion medium (b)
(B-1): n-decane (b-2): cyclohexane (b-3): isobutyl acetate (5) dispersant (c)
(C1-1): Distearic acid ester of PEG (GMw300) [trade name “IONET DS-300”, manufactured by Sanyo Chemical Industries, HLB 7.3, melting point 35 ° C., Tg 25 ° C.]
(C2-1): Dispersant obtained in Production Example 1 (HLB2.1, melting point 95 ° C., Tg 85 ° C., GMw 35,000)
(C2-2): Maleic anhydride-modified ethylene / vinyl acetate copolymer [trade name “Orevac 9318”, manufactured by Arkema Co., Ltd., HLB1.2, melting point 86 ° C., Tg 68 ° C., GMw 18,000]
(C2-3): copolymer of alkene (C30 or higher) and maleic anhydride [trade name “Diacarna 30”, manufactured by Mitsubishi Chemical Corporation, HLB2.1, melting point 65 ° C., Tg 60 ° C., GMw 9,300]
(6) Inorganic coagulant polyiron: 10% polyferric sulfate aqueous solution [trade name “Polytec”, manufactured by Nittetsu Mining Co., Ltd.]

The solid content, intrinsic viscosity [η], Mw, Mn, Mw / Mn, fractal order, angle of repose and volume average particle diameter of the polymer flocculant were determined by the above methods. Other evaluation items are as follows. TS in sewage sludge, suspended solids (SS), organic content (loss on ignition) and alkalinity were measured according to the analysis method described in “Sewage Test Method” (Japan Sewerage Association, 1984 version). .

(1) Adhesion rate (%)
The ratio based on the theoretical yield of the polymer solid content adhering to the inner wall of the reaction vessel or the stirring blade after the polymerization is defined as the adhesion rate.

(2) Content of secondary particles in polymer flocculant particles (%)
Low tap test sieve shaker [for example, Iida Seisakusho Co., Ltd. same as below. ] And the standard sieve specified in JIS Z8801-2000, and obtained by the method described in Perry's Chemical Engineers Handbook 6th Edition (published by McGraw Hill Book Company, 1984, page 21) Can do.
That is, the above standard sieve having an appropriate opening, for example, opening 2.00, 1.70, 1.40, 1.18 and 1.0 mm, 850, 710, 500, 425, 355, 300, 250, 180 Then, 50.0 g of polymer flocculant particles are taken on a standard sieve of 150 μm, shaken for 1 minute with a low tap test sieve shaker, and the weight of the particles remaining on each sieve is measured (S _W ) _i . Extraction 50 at random from the particles on each sieve, and weighed sorting the compounded secondary particles of them visually, (S _W) ratio of the secondary particles to _i (S _{P) i} (wt %). The content of the secondary particles can be obtained from the following calculation formula.
Content of secondary particles (% by weight) = 100 × [Σ [(S _W ) _i × (S _P ) _i / 100]] / 50

(3) Content (%) of hydrophobic dispersion medium (b) remaining in the polymer flocculant
The content (%) of the hydrophobic dispersion medium remaining in the polymer flocculant is obtained by the following method, and the average value of three measurements is obtained.
<Measurement method>
A shaker [model number “MK200D”, manufactured by Yamato Kagaku Co., Ltd.] was placed in a glass container with a sealed stopper having a capacity of 100 ml, and 10 g of a polymer flocculant and 50 g of isopropanol in which 0.1% of an internal standard was dissolved in advance. same as below. ] (25 ° C., 5 hours). The peak areas of (b) and the internal standard substance in the obtained supernatant were measured by the following gas chromatography method, and the content (%) of (b) remaining in the polymer flocculant from the following formula: )
Content (%) of (b) remaining in the polymer flocculant = (L / M) × F × 100
[In the formula, L = peak area of (b) / solid content weight of polymer flocculant M = peak area of internal standard substance / weight of internal standard substance F = factor relative to internal standard substance [with same weight (b) Ratio of peak areas of internal standard substance]]
Here, the composition of the hydrophobic dispersion medium (b) can be identified by a gas chromatograph mass spectrometer [model number “GCMS-QP2010”, manufactured by Shimadzu Corporation] or the like.

<Gas chromatography measurement conditions>
Gas chromatograph: GC-14B [manufactured by Shimadzu Corporation]
Column: Inner diameter 4 mmφ, length 1.6 m, glass column filler: polyethylene glycol 20M [manufactured by Shinwa Kako Co., Ltd.]
Internal standard: α-methylstyrene [manufactured by Nacalai Tesque Co., Ltd.]
Diluent: Isopropyl alcohol [Wako Pure Chemical Industries, Ltd.]
Injection temperature: 200 ° C
Column initial temperature: 110 ° C
Temperature increase rate: 5 ° C./min.
Column final temperature: 200 ° C
Sample injection volume: 1 μl

(4) Content (%) of dispersant (c) remaining in polymer flocculant
The content (%) of the dispersing agent remaining in the polymer flocculant is obtained by the following method, and the average value of three measurements is obtained.
In a glass container with a cap of 100 ml capacity, 10 g of the polymer flocculant and 50 g of cyclohexane are placed and shaken with a shaker (25 ° C., 5 hours). Cyclohexane is distilled off under reduced pressure from the obtained supernatant and the solid content weight (W) is measured. About the solid content, a nuclear magnetic resonance spectroscopy measuring apparatus [model number “JNM-ECA400WB”, manufactured by JEOL Ltd.], Fourier transform infrared spectrophotometer [model number “IRPrestige-21, manufactured by Shimadzu Corporation”, The dispersant (c) is identified and quantified (content rate q%) by the gas chromatography method or the like. The content (%) of the dispersant (c) remaining in the polymer flocculant is determined from the following formula.
(C) Content (%) remaining in the polymer flocculant = q × (W / solid weight of the polymer flocculant)

(5) Water solubility A stirring bar equipped with two plate-like PVC stirring blades (diameter: 5 cm, height: 2 cm, thickness: 0.2 cm) continuously up and down in a cross shape is a jar tester [model number “ JMD-6HS-A ", manufactured by Miyamoto Riken Kogyo Co., Ltd., and so on. ] Is used. A 500 ml beaker containing 499 g of ion-exchanged water is set here and stirred at a water temperature of 25 ° C. and 200 rpm. The total amount of 1 g (solid content) of the polymer flocculant weighed in the petri dish was poured into ion-exchanged water under stirring at a stretch, and the dissolution state 60 minutes after the addition was visually observed to dissolve the water on the basis of the following criteria. Evaluated.
<Evaluation criteria>
◎ No occurrence of undissolved, undissolved residue ○ No occurrence of undisturbed, very little undissolved △ Distinct occurrence, slightly more undissolved

(6) Water insoluble matter (%)
In a 1 L beaker, 500 g of a 0.1% sodium chloride aqueous solution was placed, and 2.5 g of a polymer flocculant was stirred at a liquid temperature of 25 ° C. and 200 rpm with a stirrer equipped with a 50 mm long and 20 mm wide stirring blade. Solid content) is gradually added and stirred for 2 hours to dissolve. The solution is filtered through a mesh weighed in advance and having a mesh size of 100 μm. The residue is placed on an aluminum dish together with the mesh and dried for 2 hours in a circulating air dryer at 120 ° C. Let the value calculated | required with the following formula be a water insoluble part (%).
Water insoluble content (%) = 100 × [residue weight after drying] / [solid content weight of polymer flocculant]]

(7) Flock particle size (mm)
Take 200 ml of sludge in a 300 ml beaker and set it in the stirring device (5). While stirring the sludge gradually with the rotation speed of the stirrer being 300 rpm, an aqueous solution of a polymer flocculant having a predetermined concentration was added by a predetermined method, and after stirring for 30 seconds, the stirring was stopped and the size of the floc was visually observed. To evaluate.
Subsequently, after further stirring for 30 seconds at a rotation speed of 650 rpm, the stirring is stopped and the size of the floc is visually evaluated again.

(8) Flock strength The ratio of each floc particle size at 650 rpm and 300 rpm in (7) above is calculated from the following formula and evaluated according to the following criteria.
Flock particle size ratio = (Flock particle size at 650 rpm) / (Flock particle size at 300 rpm)
<Evaluation criteria>
◎ Very strong (0.8 ≦ floc particle size ratio ≦ 1)
○ Strong (0.7 ≦ Flock particle size ratio <0.8)
△ Slightly weak (0.5 ≦ floc particle size ratio <0.7)
× Weak (Flock particle size ratio <0.5)

(9) Filtrate volume (ml)
Nylon filter cloth [Model No. “T-1189”, Shikishima Canvas Co., Ltd., circular shape, diameter 9 cm], Nutsche funnel, graduated cylinder that can measure 300 ml, set sludge after the above Flock particle size test Then, using a stopwatch, measure the amount of the filtrate 10 seconds and 60 seconds after the addition.

(10) Filter cloth peelability The filtered sludge is taken out together with the filter cloth with a spatula and dehydrated using a press filter tester [model number “FPT-W20”, manufactured by Miyamoto Seisakusho Co., Ltd.] (1 kg / cm ² , 60 seconds). ) And the peelability of the dewatered cake when the dewatered cake adhering to the filter cloth after the test is peeled off with a spatula is evaluated according to the following criteria.
<Evaluation criteria>
◎ Very easy to peel off (almost no filter cloth deposits)
○ Easy to peel off (Slightly attached filter cloth)
△ Slightly difficult to peel off (there is a filter cloth deposit, slightly sticking to the inside of the filter cloth)
× Hard to peel off (attaches to the inside of the filter cloth)

(11) Moisture content of cake (%)
About 3 g of the dehydrated cake after the filter cloth peelability test of (10) above was weighed (W3) in a petri dish and dried in a circulating drier at 105 ± 5 ° C. for 8 hours, and then remained in the petri dish. The dry cake weight (W4) is obtained, and the moisture content of the cake is calculated from the following equation.
Cake moisture content (%) = [(W3) − (W4)] × 100 / (W3)

Production Example 1 [Production Method of Dispersant (c2-1)]
In a reaction vessel, ethylene-vinyl acetate copolymer [trade name “AC-POLY-400”, manufactured by Honeywell, Inc., vinyl acetate unit content 14%] 171 parts, maleic anhydride 17.1 parts, xylene 117.7 The parts were charged and heated to 100 ° C. and stirred to obtain a uniform polymer solution. Into the dropping funnel, 11.8 parts of dicumyl peroxide (d-1), 11.8 parts of xylene and 0.092 parts of dodecyl mercaptan were charged and uniformly dissolved to obtain an initiator solution. The initiator solution was added from the dropping funnel to the polymer solution heated to 150 ° C. at a dropping rate of 0.4 part / min over 1 hour, and then reacted for 3 hours. Xylene was stripped at 140 to 160 ° C. for 2 hours under a reduced pressure of 3 to 20 kPa to obtain a dispersant (c2-1).

Example 1 [Production of polymer flocculant (P-1)]
[First Step] A mixed solution [aqueous phase (1)] formulated according to Table 1 was prepared at room temperature (20 to 25 ° C.). Further, the pH (20 ° C.) of the aqueous phase (1) was adjusted to 3.0 using sulfamic acid while monitoring with a pH meter. Separately, a polymerization initiator (d-2) and ion-exchanged water were blended according to Table 1 to prepare a mixed solution [aqueous phase (2)]. The aqueous phases (1) and (2) were separately sufficiently substituted with nitrogen (purity 99.999% or more; the same shall apply hereinafter) (dissolved oxygen concentration of 20 ppb or less).
Apart from these, n-decane (b-1), dispersants (c1-1) and (c2-1) are charged according to Table 1 into a reaction vessel equipped with a stirring blade (Max Blend blade) to prepare an oil phase. did. While stirring the stirring blade at a rotation speed of 340 rpm, the inside of the reaction vessel was replaced with nitrogen (gas phase oxygen concentration: 10 ppm or less), heated to 80 ° C. and held for 30 minutes, and then until the polymerization temperature shown in Table 1 Cooled down. After reaching the polymerization temperature, the aqueous phases (1) and (2) are each fed at the temperature shown in Table 1 with a dropping pump under the pressure conditions shown in Table 1, and continuously mixed with a static mixer. The entire amount of the mixed solution (monomer aqueous solution) was dropped into the reaction vessel over 2 hours. According to the above method, the volume average diameter of the droplet at the time of dropping was 0.5 mm. Thereafter, stirring was continued at the polymerization temperature shown in Table 1 for 2 hours to carry out reverse phase suspension polymerization.

[Second Step] Thereafter, 9 parts of the aqueous phase (2) was further added, and after 1 hour, an aqueous solution in which 14 parts of sodium bisulfite and 0.19 parts of mercaptoacetic acid were dissolved in 10 parts of ion-exchanged water was additionally added. Then, from the time of the addition, the stirring was continued at 55 ° C. for 30 minutes to complete the polymerization.
Thereafter, the temperature of the reaction system was set to be equal to or higher than the melting point of the dispersant (c) and stirred for 30 minutes, and the primary particles were combined to form secondary particles. The temperature of the reaction system was 55 ° C., and azeotropic dehydration was performed under reduced pressure (3 to 20 kPa) to obtain a slurry. The slurry was supplied to a vacuum filter and subjected to solid-liquid separation, and then the solid content was dried in a vacuum dryer (1.3 kPa, 40 ° C. × 2 hours) to obtain the water-soluble copolymer (A-1). A polymer flocculant (P-1) containing dry particles was obtained. The evaluation results for (P-1) are shown in Table 1.

Examples 2 to 8, Comparative Examples 1 to 4 [Production of polymer flocculants (P-2) to (P-8), (R-1) to (R-4)]
In Example 1, the polymer flocculants (P-2) to (P-8) were prepared in the same manner as in Example 1 except that the blending composition, polymerization conditions, etc. were changed according to Table 1 in [First Step]. , (R-1) to (R-4) were obtained. The evaluation results for these are shown in Table 1. The polymerization of Example 7 was performed under reduced pressure boiling point polymerization conditions.

Examples 9 to 16 and Comparative Examples 5 to 8 [Performance evaluation of polymer flocculant]
Each of the obtained polymer flocculants was dissolved in ion exchange water to obtain an aqueous solution having a solid content of 0.2%. 500 ml of anaerobic digested sludge [pH 6.8, TS 2.8%, SS 2.6%, organic content 82%, fiber content 8%, alkalinity 4923mg-CaCO ₃ / L] collected from A city treatment plant In a beaker, according to Table 2, 45 parts of each polymer flocculant aqueous solution (solid content addition amount 1.6% / TS at this time) and polyiron are added, and the performance of the polymer flocculant is improved according to the above method. evaluated. The results are shown in Table 2.
In addition, when adding the said polyiron (10% aqueous solution), polyiron is added beforehand so that it may become the polyiron pure part (% / TS) of Table 2 with respect to 1,000 parts of mixing raw sludge. Then, each aqueous solution of the polymer flocculant was added.

From Table 2, Examples 9 to 16 have better water solubility than Comparative Examples 5 to 8, and Examples 9, 10, 11, and 12 are Comparative Examples 5, 6, 7, and 8, respectively. Compared with, flocs with large particle size are formed, and flocs once formed under low agitation (300 rpm) are less likely to break even under high agitation (650 rpm) (high flock strength), resulting in a large amount of liquid after 10 seconds This shows that the initial filtration rate is high and that the dehydrating property (water content of the dehydrated cake) is excellent.

Since the polymer flocculant of the present invention exhibits a specific agglomeration performance that has not been found in the past, it is used for dewatering sewage sludge, for flocculation / sedimentation of wastewater, for mud treatment in the civil engineering field, muddy water at the time of reclamation It can be used widely and suitably as a polymer flocculant for promoting sedimentation separation, improving drainage yield in papermaking processes, enhancing paper strength, and tertiary recovery of petroleum.

Claims (31)

1. A monomer aqueous solution containing a water-soluble unsaturated monomer (a) and a polymerization initiator (d) is dropped into a mixed liquid of the hydrophobic dispersion medium (b) and the dispersant (c) to cause reverse phase suspension polymerization. A polymer flocculant comprising dried particles of the water-soluble (co) polymer (A), and comprising secondary particles in which the particles are combined with single particles (primary particles).
2. The polymer flocculant according to claim 1, wherein the content of secondary particles in the dry particles is 1 to 100% by weight.
3. 3. The polymer flocculant according to claim 1, wherein the secondary particles in the dry particles have a volume average particle size of 150 to 3,000 μm.
4. 2. (a) is at least one selected from the group consisting of (meth) acryloyloxyethyl dialkylamine salts, (meth) acryloyloxyethyl trialkylammonium salts, (meth) acrylamides and acrylic acid (salts). 4. The polymer flocculant according to any one of items 1 to 3. .
5. The polymer flocculant according to any one of claims 1 to 4, wherein the monomer content in the monomer aqueous solution is 40 to 80 wt%.
6. 6. The dropping of the aqueous monomer solution is a dropping performed while continuously mixing an aqueous solution containing 10 to 20 ° C. containing the water-soluble unsaturated monomer (a) and the polymerization initiator (d). Polymer flocculants.
7. The polymer flocculant according to any one of claims 1 to 6, wherein in dropping the monomer aqueous solution, the volume average diameter of the droplet is 0.1 to 3 mm.
8. The polymer flocculant according to any one of claims 1 to 7, wherein the dispersant (c) comprises a dispersant (c2) having a glass transition temperature (Tg) of 60 to 100 ° C.
9. The polymer flocculant according to any one of claims 1 to 8, which has a polymerization temperature of 70 ° C or lower.
10. The polymer flocculant according to any one of claims 1 to 9, wherein the polymerization is vacuum polymerization or vacuum boiling point polymerization.
11. The (A) has an intrinsic viscosity of 1 to 40 dl / g and a weight average molecular weight (Mw) to number average molecular weight (Mn) ratio (Mw / Mn) of 1 to 30. Polymer flocculant.
12. The polymer flocculant according to any one of claims 1 to 11, wherein the secondary particles have a fractal order of 1.2 to 1.9.
13. The polymer flocculant according to any one of claims 1 to 12, wherein the content of the hydrophobic dispersion medium (b) in the polymer flocculant is 5% by weight or less.
14. The polymer flocculant according to any one of claims 1 to 13, wherein the content of the dispersing agent (c) in the polymer flocculant is 0.01 to 1% by weight.
15. The polymer flocculant according to any one of claims 1 to 14, wherein the water-insoluble matter of the polymer flocculant is 5% by weight or less.
16. A monomer aqueous solution containing the water-soluble unsaturated monomer (a) and the polymerization initiator (d) is dropped into the mixed liquid of the hydrophobic dispersion medium (b) and the dispersant (c) to cause reverse phase suspension polymerization. A method for producing a polymer flocculant, comprising dry particles of a water-soluble (co) polymer (A), and secondary particles formed by combining single particles (primary particles) with the particles. .
17. The production method according to claim 16, wherein the secondary particles are obtained by combining the primary particles with the reaction system temperature equal to or higher than the melting point of the dispersing agent (c) after the polymerization reaction.
18. The production method according to claim 16 or 17, wherein the content of secondary particles in the dry particles is 1 to 100% by weight.
19. The production method according to any one of claims 16 to 18, wherein the volume average particle diameter of the secondary particles in the dry particles is from 150 to 3,000 µm.
20. The method according to any one of claims 16 to 19, wherein the content of (a) in the aqueous monomer solution is 40 to 80% by weight.
21. 21. The dropping of the monomer aqueous solution is a dropping performed while continuously mixing the aqueous solution of 10 to 20 ° C. containing the water-soluble unsaturated monomer (a) and the polymerization initiator (d). Manufacturing method.
22. The production method according to any one of claims 16 to 21, wherein in dropping the monomer aqueous solution, the volume average diameter of the droplet is 0.1 to 3 mm.
23. The production method according to any one of claims 16 to 22, wherein the dispersant (c) comprises a dispersant (c2) having a glass transition temperature (Tg) of 60 to 100 ° C.
24. The production method according to any one of claims 16 to 23, wherein the polymerization temperature is 70 ° C or lower.
25. The production method according to any one of claims 16 to 24, wherein the polymerization is a reduced pressure polymerization or a reduced pressure boiling point polymerization.
26. The (A) has an intrinsic viscosity of 1 to 40 dl / g and a weight average molecular weight (Mw) to number average molecular weight (Mn) ratio (Mw / Mn) of 1 to 30. Production method.
27. The production method according to any one of claims 16 to 26, wherein the secondary particles have a fractal order of 1.2 to 1.9.
28. The production method according to any one of claims 16 to 27, wherein the content of (b) in the polymer flocculant is 5% by weight or less.
29. The production method according to any one of claims 16 to 28, wherein the content of the dispersing agent (c) in the polymer flocculant is 0.01 to 1% by weight.
30. The production method according to any of claims 16 to 29, wherein the water-insoluble matter of the polymer flocculant is 5% by weight or less.
31. The polymer flocculant according to any one of claims 1 to 15, wherein the polymer flocculant is added to and mixed with sludge or wastewater to form flocs and solid-liquid separation. A method for treating sludge or wastewater, characterized by being used.