JP2010215867A - Water-soluble polymer composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sludge dehydrating agent, which satisfies a need to lower the water content of a dehydration cake of namely sludge with low fiber contents, for which dehydration is performed with difficulty, such as excess sludge and digested sludge at sewage works, can cope with a need to increase the amount of an agent to be added, which is also thought to be a drawback of crosslinked or branched water-soluble polymers, and can suppress an increase in cost. <P>SOLUTION: A water soluble polymer composition comprises (A) a water soluble cationic polymer having a specific composition and structure, (B) a water soluble amphoteric polymer having a specific composition, (C) a water soluble amphoteric polymer having a cationic functional group and an anionic functional group and the composition ratio differing from that of (B), and (D) an acidic substance. The water-soluble polymer composition can be produced by compounding the water soluble cationic polymer (A) having a charge inclusion ratio of 35% or more and 90% or less. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a water-soluble polymer composition, and more specifically, a water-soluble polymer (A) having a specific structure and a cationic functional group having a charge inclusion rate of 35% to 90%, and a cationic functional group And an amphoteric water-soluble polymer (B) having an anionic functional group, an amphoteric water-soluble polymer (C) having an ionic functional group having a composition ratio different from that of (B), and an acidic substance (D) And a water-soluble polymer composition.

Conventionally, a cationic polymer flocculant has been widely used for dehydration of organic sludge generated in sewage, human waste, etc., and an amphoteric polymer flocculant has been proposed (Patent Document 1). In recent years, there is a strong tendency for sewage treatment plants to require a reduction in the moisture content of the dehydrated cake, which is not possible with the simple cationic or amphoteric polymers described above. Moreover, in the so-called hardly dewatered sludge with a small amount of fiber such as sewage surplus sludge and sewage digested sludge, a flocculant requiring special performance is required, and two or more kinds of flocculants are proposed.

For example, in Patent Document 2, methacrylic cationic polymer (A) and (meth) acrylic amphoteric polymer are neutralized, and in Patent Document 3, cationic polymer (A) and 3 to 30 mol% of acid groups are neutralized by alkali. The formulation of the amphoteric polymer (B) containing an anionic monomer unit is further disclosed in Patent Document 4 in which the degree of cationization is defined and the ratio of the cationic group to the anionic group is defined. Each formulation is proposed.

These are intended for the treatment of the so-called hardly dewatered sludge, but are not completely satisfied with the demand for reducing the moisture content of the dewatered cake at the sewage treatment plant. In addition, a crosslinked or branched water-soluble polymer is effective for the so-called hardly dehydrated sludge (Patent Document 5, etc.), but the problem is that the amount of chemicals added increases and processing costs are increased.
JP-A 63-260928 JP-A-8-112504 JP 2000-218297 A JP-A-9-57299 Japanese Patent No. 3218578

The object of the present invention is to satisfy the performance of dewatering cake moisture content reduction for so-called hardly dewatered sludge with low fiber content such as sewage surplus sludge and sewage digested sludge in a sewage treatment plant,
At the same time, it is to develop a sludge dewatering agent that can cope with an increase in the amount of chemicals added, which is a difficulty of water-soluble polymers that are crosslinked or branched.

As a result of intensive studies to solve the above problems, the present inventors have reached the invention described below.

That is, the invention of claim 1 includes a water-soluble polymer (A) having a cationic functional group represented by the following (Definition 1) or (Definition 2) having a charge inclusion ratio of 35% to 90%, and a cationic functional group: And a water-soluble polymer (B) having an anionic functional group, a water-soluble polymer (C) having a composition ratio different from that of (B), a water-soluble polymer (C) having an anionic functional group, and an acidic substance (D) It is a water-soluble polymer composition.

(Definition 1) In the case of a water-soluble cationic polymer and an amphoteric and water-soluble amphoteric polymer having a positive difference in the copolymerization rate between a cationic monomer and an anionic monomer, the charge inclusion rate [%] = (1 −α / β) × 100
α is a titration amount obtained by titrating a water-soluble cationic polymer or an amphoteric water-soluble polymer aqueous solution adjusted to pH 4.0 with acetic acid with a potassium polyvinyl sulfonate aqueous solution. β is a water-soluble cationic polymer or an amphoteric water-soluble polymer aqueous solution adjusted to pH 4.0 with acetic acid, and an aqueous polyvinyl sulfonate potassium solution is used to neutralize the charge of the water-soluble cationic polymer or amphoteric water-soluble polymer. A titration amount obtained by adding a sufficient amount to perform, and then subtracting the titration amount titrated with an aqueous polydiallyldimethylammonium chloride solution from the blank value. Here, the blank value is a titration amount obtained by titrating a potassium polyvinylsulfonate aqueous solution with a polydiallyldimethylammonium chloride aqueous solution when no water-soluble cationic polymer or amphoteric water-soluble polymer aqueous solution was added.

(Definition 2) In the case of a water-soluble polymer that is amphoteric and has a negative difference in copolymerization rate between a cationic monomer and an anionic monomer, the charge inclusion rate [%] = (1−α / β) × 100
α is a titration amount obtained by titrating a water-soluble amphoteric polymer aqueous solution adjusted to pH 10.0 with ammonia with a polydiallyldimethylammonium chloride aqueous solution. β is a water-soluble amphoteric polymer aqueous solution adjusted to pH 10.0 with ammonia, and a polydiallyldimethylammonium chloride aqueous solution is added in an amount sufficient to neutralize the charge of the water-soluble amphoteric polymer, and then a potassium polyvinyl sulfonate aqueous solution Titration volume obtained by subtracting the titration volume titrated with the blank value. Here, the blank value is a titration amount obtained by titrating a diallyldimethylammonium chloride aqueous solution with a potassium polyvinyl sulfonate aqueous solution when no water-soluble amphoteric polymer aqueous solution was added.

The invention of claim 2 is characterized in that the water-soluble polymer (A) is a monomer represented by the following general formula (1) and / or general formula (2): And a monomer mixture consisting of 0 mol% to 50 mol% and a nonionic monomer in a range of 0 mol% to 99 mol%. The water-soluble polymer composition as described in 1. above.
General formula (1)
R ₁ is hydrogen or a methyl group, R ₂ , R ₃ and R ₄ are alkyl groups having 1 to 3 carbon atoms, alkoxy groups or benzyl groups, which may be the same or different. A is oxygen or NH, B is an alkylene group or an alkoxylene group having 2 to 4 carbon atoms, _{X 1} ^- represents each an anion.
General formula (2)
R ₅ and R _{6 each} represent hydrogen or a methyl group, R ₇ and R ₈ each represent an alkyl group having 1 to 3 carbon atoms, an alkoxy group or a benzyl group, and X ₂ ⁻ represents an anion.
General formula (3)
R ₉ is hydrogen or CH ₂ COOY ₂ , R ₁₀ is hydrogen, methyl group or COOY ₂ , Q is SO ₃ ⁻ , C ₆ H ₄ SO ₃ ⁻ , CONHC (CH ₃ ) ₂ CH ₂ SO ₃ ⁻ , C ₆ H ₄ COO ⁻ or COO ⁻ , and Y ₁ and Y ₂ each represent hydrogen or a cation.

The invention of claim 3 is characterized in that the water-soluble polymers (B) and (C) are 1 mol% or more and 99 mol% or less of the monomer represented by the general formula (1) and / or the general formula (2), It is a copolymer of a monomer mixture composed of a monomer represented by the general formula (3) in a range of 1 mol% to 99 mol% and a nonionic monomer in a range of 0 mol% to 98 mol%. The water-soluble polymer composition according to claim 1 or 2.

In the invention of claim 4, the molar ratio of the cationic structural unit (a) and the anionic structural unit (b) constituting the water-soluble polymer (B) is 10 ≧ (a) / (b) ≧ 1. And the molar ratio of the cationic structural unit (c) and the anionic structural unit (d) constituting the water-soluble polymer (C) is 1> (c) / (d) ≧ 0.1 The water-soluble polymer composition according to claim 1.

The water-soluble polymer composition according to claim 1, wherein the pH of a 0.1 wt% aqueous solution of the water-soluble polymer composition is 4.0 or less. It is.

In the invention of claim 6, the mass mixing ratio of the water-soluble polymer (A), the water-soluble polymer (B) and the water-soluble polymer (C) is (A) :( B) :( C) = 40. It is the range of -90: 5-55: 5-55, The water-soluble polymer composition of Claim 1 to 5 characterized by the above-mentioned.

The invention according to claim 7 is the water-soluble polymer composition according to claims 1 to 6, wherein the water-soluble polymer composition is made of powder.

The invention according to claim 8 is characterized in that the water-soluble polymer (A) is a polyfunctional compound having a non-miscible organic liquid in water by a surfactant, a continuous phase, a cationic monomer, and a plurality of unsaturated double bonds. 2. A water-in-oil emulsion liquid obtained by emulsifying an aqueous monomer mixture containing a monomer as an essential component so as to form a dispersed phase and polymerizing it, wherein the liquid is obtained by drying. To 7. The water-soluble polymer composition according to item 7.

The invention of claim 9 is the method of using the water-soluble polymer composition according to claim 1, wherein the water-soluble polymer composition is used as a sludge dehydrating agent.

The present invention relates to a water-soluble polymer (A) having a cationic functional group represented by (Definition 1) or (Definition 2) having a charge inclusion rate of 35% to 90%, a cationic functional group and an anionic functional group Water-soluble polymer combining amphoteric water-soluble polymer (C) and acidic substance (D) having a cationic functional group and an anionic functional group having a composition ratio different from that of (B) It is characterized by comprising a polymer composition.

The water-soluble polymer composition of the present invention satisfies the performance of reducing the moisture content of a dehydrated cake with respect to a so-called hardly dewatered sludge having a small amount of fibers such as sewage surplus sludge and sewage digested sludge in a sewage treatment plant, and at the same time cross-linking or It is also possible to cope with an increase in the amount of drug added, which is a difficulty of branched water-soluble polymers.

A water-soluble polymer having a cationic functional group with a charge inclusion ratio of less than 35% and 5% or more has many contact sites with suspended particles because most of the charge is exposed on the polymer surface, and as a result, apparent It tends to become the upper charge saturation.

In general, with cationic water-soluble polymers, the water content of the dehydrated cake decreases as the amount added increases, but cationic water-soluble polymers with most of the charge exposed on the polymer surface are charged and saturated. However, excess water-soluble polymer becomes unadsorbed, and the released water-soluble polymer causes an increase in sludge viscosity. Further, it causes inhibition of re-aggregation after dispersion by applying strong shearing. Flock is difficult to generate.

On the other hand, since the water-soluble polymer having a cationic functional group having a charge inclusion rate of 35% or more and 90% or less forms fine particles, it is presumed that charges are contained inside the particles.

When a water-soluble polymer having a cationic cationic functional group is added to the sludge, it adsorbs to the suspended particles and acts as an adhesive between the particles, resulting in particle aggregation. It is presumed that the formation of a “clogged” agglomerated state forms a tighter and stronger floc and more effectively reduces the moisture content of the dewatered cake.

In a water-soluble polymer having a cationic functional group having a charge inclusion ratio of less than 35% and 5% or more, a water-soluble polymer having a cationic functional group having a charge inclusion ratio of 35% or more and 90% or less even in a region where charge inclusion is possible. The polymer is efficiently adsorbed on the suspended particles, so that there is little unadsorbed water-soluble polymer, it is not liberated in the sludge, and sludge viscosity does not increase.

The blended amphoteric water-soluble polymer has a cationic group and an anionic group in the molecule, so there is also a bond between the aggregated particles that have adsorbed and agglomerated this molecule, and also aggregated particles generated by the cationic water-soluble polymer It is considered that the amount added can be saved as compared with the case of the cationic water-soluble polymer alone.

The main role of the amphoteric water-soluble polymer is to maintain the balance between intermolecular or aggregated particles and ionicity in the system. It is possible to reinforce the intermediation between aggregated particles by combining a cationic polymer. Furthermore, by introducing a water-soluble polymer with a complex composition, an ionic buffer state is generated, and excessive cationicity is prevented. Therefore, it is considered to prevent a decrease in the aggregation performance.

The acidic substance prevents incomplete dissolution due to the formation of an intramolecular ion complex of the amphoteric water-soluble polymer, and prevents hydrolysis of the composition in an aqueous solution.

First, the cationic water-soluble polymer (A) having a charge inclusion rate of 35% or more and 90% or less will be described.

The charge inclusion rate is defined as follows.
(Definition 1) In the case of a water-soluble cationic polymer and an amphoteric and water-soluble amphoteric polymer having a positive difference in the copolymerization rate between a cationic monomer and an anionic monomer, the charge inclusion rate [%] = (1 −α / β) × 100
α is a titration amount obtained by titrating a water-soluble cationic polymer or an amphoteric water-soluble polymer aqueous solution adjusted to pH 4.0 with acetic acid with a potassium polyvinyl sulfonate aqueous solution. β is a water-soluble cationic polymer or an amphoteric water-soluble polymer aqueous solution adjusted to pH 4.0 with acetic acid, and an aqueous polyvinyl sulfonate potassium solution is used to neutralize the charge of the water-soluble cationic polymer or amphoteric water-soluble polymer. A titration amount obtained by adding a sufficient amount to perform, and then subtracting the titration amount titrated with an aqueous polydiallyldimethylammonium chloride solution from the blank value. Here, the blank value is a titration amount obtained by titrating a potassium polyvinylsulfonate aqueous solution with a polydiallyldimethylammonium chloride aqueous solution when no water-soluble cationic polymer or amphoteric water-soluble polymer aqueous solution was added.

(Definition 2) In the case of a water-soluble polymer that is amphoteric and has a negative difference in copolymerization rate between a cationic monomer and an anionic monomer, the charge inclusion rate [%] = (1−α / β) × 100
α is a titration amount obtained by titrating a water-soluble amphoteric polymer aqueous solution adjusted to pH 10.0 with ammonia with a polydiallyldimethylammonium chloride aqueous solution. β is a water-soluble amphoteric polymer aqueous solution adjusted to pH 10.0 with ammonia, and a polydiallyldimethylammonium chloride aqueous solution is added in an amount sufficient to neutralize the charge of the water-soluble amphoteric polymer, and then a potassium polyvinyl sulfonate aqueous solution Titration volume obtained by subtracting the titration volume titrated with the blank value. Here, the blank value is a titration amount obtained by titrating a diallyldimethylammonium chloride aqueous solution with a potassium polyvinyl sulfonate aqueous solution when no water-soluble amphoteric polymer aqueous solution was added.

A water-soluble polymer with a high charge inclusion rate has a rounded shape in solution, and the ionic groups present inside the particle are unlikely to appear on the outside, and the reaction with the opposite charge is slow. The water-soluble polymer having a charge inclusion rate of 35% or more and 90% or less shows a case where the crosslinking is particularly enhanced.

In other words, the water-soluble polymer in a dilute solution is considered to undergo an electrostatic neutralization reaction not only to the cationic charge on the surface but also to the internal charge, resulting in a small charge inclusion rate. If the cross-linking is high, charge neutralization inside the particles is considered to be inhibited, and the charge inclusion rate increases.

In order to produce the water-soluble polymer (A) having a cationic functional group having a charge inclusion ratio of 35% or more and 90% or less in the present invention, it is represented by the general formula (1) and / or the general formula (2). A cationic monomer is essential.

Examples of the monomer represented by the general formula (1) include (meth) acryloyloxyalkyl quaternary ammonium salts, that is, (meth) acryloyloxyethyltrimethylammonium chloride, (meth) acryloyloxyethyldimethylbenzylammonium chloride, (Meth) acryloyloxy-2-hydroxypropyltrimethylammonium bromide or the like, or (meth) acryloyloxyalkyl tertiary amine salt, that is, (meth) acryloyloxyethyldimethylamine sulfate, (meth) acryloyloxypropyldimethylamine hydrochloride, etc. Or (meth) acryloylaminoalkyl quaternary ammonium salts, ie (meth) acryloylaminopropyltrimethylammonium chloride, (meth) acryloyl Such as amino propyl trimethyl ammonium methylsulfate, more (meth) acryloyl amino (hydroxy) alkyl tertiary amine salts, i.e., and (meth) acryloyl-aminoethyl dimethylamine hydrochloride.

Examples of the monomer represented by the general formula (2) include di (meth) allyldimethylammonium chloride, di (meth) allyldimethylammonium bromide, di (meth) allyldiethylammonium chloride, di (meth) allyldi Examples thereof include propylammonium chloride.

Examples of the anionic monomer represented by the general formula (3) include vinyl sulfonic acid, vinyl benzene sulfonic acid or 2-acrylamido 2-methylpropane sulfonic acid, methacrylic acid, acrylic acid, itaconic acid, maleic acid or Examples thereof include p-carboxystyrene.

Nonionic monomers include acrylamide, N, N-dimethylacrylamide, vinyl acetate, acrylonitrile, methyl acrylate, 2-hydroxyethyl (meth) acrylate, diacetone acrylamide, N-vinylpyrrolidone, N-vinylformamide. , N-vinylacetamide, acryloylmorpholine and the like.

In the present invention, in order to produce the cationic water-soluble polymer (A) having a charge encapsulation rate of 35% or more and 90% or less, the crosslinkable monomer is added to 0.0005 to 0.0050 mol%, preferably 0.0008 to 0.002 mol% is present.

Examples of the crosslinkable monomer include N, N-methylenebis (meth) acrylamide, triallylamine, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, and dimethacrylic acid. Acid-1,3-butylene glycol, polyethylene glycol di (meth) acrylate, N-vinyl (meth) acrylamide, N-methylallylacrylamide, glycidyl acrylate, polyethylene glycol diglycidyl ether, acrolein, glyoxal, vinyltrimethoxysilane In this case, the crosslinking agent is more preferably a water-soluble polyvinyl compound, and most preferably N, N-methylenebis (meth) acrylamide.

Use of a chain transfer agent such as sodium formate or isopropyl alcohol in combination is also effective as a method for adjusting the crosslinkability.

There is no restriction | limiting in particular as the range of the cationic monomer which comprises water-soluble polymer (A), It is the range of 1 mol% or more and 100 mol% or less, The range of anionic monomer is 0 mol% or more and 50 mol% In the following, it is preferably in the range of 0 mol% to 30 mol%, and the range of the nonionic monomer is in the range of 0 mol% to 99 mol%, preferably 0 mol% to 95 mol%.

The molecular weight of the water-soluble polymer (A) is 5 to 20 million in terms of weight average molecular weight, preferably 5 to 12 million, and most preferably 7 to 10 million.

There is no particular limitation on the polymerization method of the water-soluble polymer (A), and there is no particular limitation such as polymerization of the monomer mixture in an aqueous solution, dispersion in a salt solution or water-immiscible organic liquid. Although it is possible by the method, since the higher the charge inclusion rate, the higher the cross-linking, from the viewpoint of preventing the gel-like product, it is preferably dispersion polymerization in a salt aqueous solution or in a water-immiscible organic liquid, Considering the removal of impurities such as salt and water, dispersion polymerization in a water-immiscible organic liquid is particularly preferable.

The water-soluble polymer (A) can be in the form of a liquid, a solid, etc., but it has a small amount of impurities such as salt, water, water, an immiscible organic liquid, and has a good solubility in water. Solid is preferred.

There is no particular limitation on the method for obtaining the powdery water-soluble polymer (A). After polymerizing a high concentration aqueous solution in the presence of a polymerization initiator, the gelled material is minced with a meat chopper and the like, dried, A method of pulverizing into powder, a method of obtaining a bead-like powder by suspension polymerization in water in a non-miscible organic solvent, or a dispersion in a salt solution or water immiscible organic liquid Examples include a method of obtaining a powder by dry granulation after polymerization, but in the presence of an emulsifier in a water-immiscible organic liquid, especially from the viewpoint of preventing gel-like products or considering removal of impurities such as salt and water. A method of obtaining a powder by drying and granulating a polymerized water-in-oil emulsion polymer is particularly preferred.

There is no particular limitation on the method of drying and granulating, such as a method of spray-drying and granulating a water-in-oil emulsion polymer, a method of granulating after drying a dried product obtained by drying a liquid dispersion polymer into a sheet, and the like. Can be mentioned.

The water-in-oil emulsion polymer was added in a molar ratio that maintains the water solubility of the ionic monomer or the monomer copolymerizable with the ionic monomer and the polymer produced for these monomers. A monomer mixture containing a crosslinkable monomer is water, an oily substance comprising at least water-immiscible hydrocarbons, an amount effective to form a water-in-oil emulsion and at least one interface having an HLB It is synthesized by mixing the activator, stirring vigorously to form a water-in-oil emulsion and polymerizing.

Examples of oily substances composed of hydrocarbons used as a dispersion medium include paraffins, mineral oils such as kerosene, light oil, and middle oil, or hydrocarbon-based synthetic oils having characteristics such as boiling point and viscosity substantially in the same range as these. Or a mixture thereof. As content, it is the range of 20 mass%-50 mass% with respect to the water-in-oil type emulsion whole quantity, Preferably it is the range of 20 mass%-35 mass%.

Examples of at least one surfactant having an amount effective to form a water-in-oil emulsion and HLB are HLB 1-8 nonionic surfactants, specific examples of which include sorbitan monooleate Sorbitan monostearate, sorbitan monopalmitate and the like. The addition amount of these surfactants is 0.5 to 10% by mass, preferably 1 to 5% by mass, based on the total amount of the water-in-oil emulsion.

In this case, the emulsion emulsified with a high HLB surfactant to form a water-in-oil emulsion and polymerized is compatible with water as it is, so there is no need to add a phase inversion agent. The HLB of these surfactants is 9-20, preferably 11-20. Examples of such surfactants are cationic surfactants and HLB 9-15 nonionic surfactants, such as polyoxyethylene polyoxypropylene alkyl ether systems, polyoxyethylene alcohol ether systems, and the like It is.

When emulsified and polymerized with a low-HLB surfactant, a hydrophilic interfacial modifier called a phase inversion agent is added after the polymerization to make the emulsion particles covered with the oil film easy to adapt to water, The molecule is treated so that it is easily dissolved, diluted with water and used for each application. Examples of hydrophilic surfactants are cationic surfactants and nonionic surfactants of HLB 9-15, such as polyoxyethylene polyoxypropylene alkyl ether systems and polyoxyethylene alcohol ether systems. is there.

The water-soluble polymer (B) and the water-soluble polymer (C) are a monomer represented by the general formula (1) and / or the general formula (2) and a monomer represented by the general formula (3). The composition of the monomer mixture of the mixture is 1 mol% or more and 99 mol% or less of the monomer represented by the general formula (1) and / or the general formula (2), and is represented by the general formula (3). The monomer ranges from 1 mol% to 99 mol% and nonionic monomers from 0 mol% to 98 mol%.

The molar ratio of the composition of the cationic monomer represented by the general formula (1) and / or the general formula (2) and the monomer represented by the general formula (3) in the water-soluble polymer (B) is: Corresponding to the molar ratio (a) / (b) of the cationic structural unit (a) and the anionic structural unit (b) constituting the water-soluble polymer (B), 10 ≧ (a) / (b) ≧ 1 It is particularly preferred that The reason for this is that when combined with the water-soluble polymer (C) described later, the water-soluble polymer (B) is in the range of 10 ≧ (a) / (b) ≧ 1 (A), (B) and This is because the water-soluble polymer composition of the present invention blended with (c) exhibits a very remarkable effect as a whole. When 10 ≦ (a) / (b), the effect of amphoteric is not manifested and it is not practical.

The molar ratio of the composition of the cationic monomer represented by the general formula (1) and / or the general formula (2) and the monomer represented by the general formula (3) in the water-soluble polymer (C) is: Corresponding to the molar ratio (a) / (b) of the cationic structural unit (a) and the anionic structural unit (b) constituting the water-soluble polymer (B), there is a particular limitation if it is different from the water-soluble polymer (C). However, it is particularly preferable that 1> (c) / (d) ≧ 0.1. The reason for this is that, as described above, when the water-soluble polymer (B) is in the range of 10 ≧ (a) / (b) ≧ 1, (A), (B) and (c) are blended. This is because the water-soluble polymer composition exhibits a very remarkable effect as a whole. When (c) / (d) ≦ 0.1, the anionicity is too high and the effect is lowered, which is not practical.

Although there is no particular limitation on the charge inclusion rate of the water-soluble polymers (B) and (C), the electrification inclusion rate is preferably less than 35% and 5% or more.

Although there is no restriction | limiting in particular about the molecular weight of water-soluble polymer (B) and (C), It is preferable that it is the range of 2 million to 25 million in a weight average molecular weight, and is especially the range of 4 million to 15 million.

There is no particular limitation on the method for producing the water-soluble polymers (B) and (C), and the water-soluble polymers (B) and (C) can be obtained by the same method as that for the water-soluble polymer (A), but the charge inclusion rate is less than 35% and 5% or more. In some cases, considering production efficiency and impurity removal efficiency, an aqueous solution of the monomer mixture is preferably solution-polymerized in the presence of a polymerization initiator, dried and pulverized, and granulated to form a powder.

In general, a water-soluble polymer having a cationic functional group having a charge inclusion ratio of less than 35% and 5% or more has many contact sites with suspended particles because most of the charge is exposed on the polymer surface. It tends to be apparently charge saturation.

In addition, with cationic water-soluble polymers, the water content of the dehydrated cake decreases with increasing amount of addition, but cationic water-soluble polymers with most of the charge exposed on the polymer surface are charged with saturation. However, the excess water-soluble polymer becomes unadsorbed, and the released water-soluble polymer causes an increase in the sludge viscosity, and further inhibits reaggregation after dispersion by applying strong shearing. It is hard to generate a frock.

On the other hand, since the water-soluble polymer having a cationic functional group having a charge inclusion rate of 35% or more and 90% or less forms fine particles, it is presumed that charges are contained inside the particles.

When a water-soluble polymer having a cationic cationic functional group is added to the sludge, it adsorbs to the suspended particles and acts as an adhesive between the particles, resulting in particle aggregation. It is presumed that the formation of a “clogged” agglomerated state forms a tighter and stronger floc and more effectively reduces the moisture content of the dewatered cake.

In a water-soluble polymer having a cationic functional group having a charge inclusion ratio of less than 35% and 5% or more, a water-soluble polymer having a cationic functional group having a charge inclusion ratio of 35% or more and 90% or less even in a region where charge inclusion is possible. The polymer is efficiently adsorbed on the suspended particles, so that there is little unadsorbed water-soluble polymer, it is not liberated in the sludge, and sludge viscosity does not increase.

However, a water-soluble polymer having a cationic functional group having a charge inclusion rate of 35% or more and 90% or less tends to be insufficient in terms of charge neutralization in view of charge inclusion.

These are phenomena that occur when a cationic water-soluble polymer is used alone. By mixing amphoteric polymers with water-soluble polymers having a cationic functional group with a charge encapsulation rate of 35% or more and 90% or less. It can be solved.

The blended amphoteric water-soluble polymer has a cationic group and an anionic group in the molecule, so there is also a bond between the aggregated particles that have adsorbed and agglomerated this molecule, and also aggregated particles generated by the cationic water-soluble polymer It is considered that the amount added can be saved as compared with the case of the cationic water-soluble polymer alone.

The main role of the amphoteric water-soluble polymer is to maintain the balance between intermolecular or aggregated particles and ionicity in the system. It is possible to reinforce the intermediation between aggregated particles by combining a cationic polymer. Furthermore, by introducing a water-soluble polymer with a complex composition, an ionic buffer state is generated, and excessive cationicity is prevented. Therefore, it is considered to prevent a decrease in the aggregation performance.

Therefore, the water-soluble polymer composition is a combination of the water-soluble polymer (A), the water-soluble polymer (B), the water-soluble polymer (C) and the acidic substance (D). The mass mixing ratio of (A), water-soluble polymer (B) and water-soluble polymer (C) is in the range of (A) :( B) :( C) = 40-90: 5-55: 5-55. It is preferable that

When the proportion of the water-soluble polymer (A) is 40% by weight or less, the moisture content of the sludge tends to increase when used as a sludge dehydrating agent, and when it is 90% by weight or more, a large amount of addition is required.

Although there is no restriction | limiting in particular in the ratio of water-soluble polymer (B) and (C), the one where a weight mixing ratio is near is preferable, and it is the range of (B) :( C) = 30-70: 70-30. Particularly preferred.

The water-soluble polymer composition of the present invention has an aqueous solution pH of usually 4.0 or less, preferably 3.0 or less when an aqueous solution having a solution concentration of 0.1% by mass close to the lower limit when added to a treated control is obtained. When the aqueous solution pH exceeds 4.0, sufficient performance cannot be obtained, so an acidic substance is blended.

Since an amphoteric water-soluble polymer is added, an ion complex is formed when the solution pH is in the range of about 5 to about 9, and the solution becomes cloudy. However, when this ion complex is formed, the performance decreases when added to a treatment control such as sludge. In addition, when the pH is higher than about 5, the (meth) acrylic water-soluble polymer used in the present invention is subject to hydrolysis and easily deteriorates.

As such an acidic substance (D), any of an inorganic acid and an organic acid can be used, and examples thereof include hydrochloric acid, sulfuric acid, nitric acid, sulfamic acid, succinic acid, citric acid, adipic acid, and the like, and particularly sulfamic acid and succinic acid. , Citric acid, adipic acid, and the like are preferably solid acidic substances, and the addition amount is 5 to 20% by mass, preferably 7 to 15% by mass in terms of solid content of the water-soluble polymer. It is preferable to adjust the addition amount so as to ensure that the pH is 4 or less even when dissolved at a concentration of 1% by mass.

There is no particular limitation on the form of the water-soluble polymer composition of the present invention, and any form of liquid or powdered solid is possible, but it may be a powdered solid in consideration of labor and costs for production and transportation. preferable.

The method for obtaining the water-soluble polymer composition is not particularly limited, and the water-soluble polymer (A), (B) and (C) obtained as a liquid is mixed with the acidic substance (D) to form a water-soluble polymer. A method for obtaining a composition liquid, a method for obtaining a water-soluble polymer (A), (B) and (C) obtained as an aqueous solution by mixing an acidic substance (D), followed by drying and pulverizing and granulating, a powder form Any form of the water-soluble polymer (A), (B) and (C) obtained by mixing the powdered acidic substance (D) with the powdered water-soluble polymer (A) is possible. ), (B) and (C) are preferably mixed with a powdered acidic substance (D).

The water-soluble polymer composition of the present invention can be used as a polymer flocculant, such as sludge dewatering agent, sedimentation of suspended substances in suspension, flotation agent, yield improver for papermaking raw materials, filter. It can be used as a water-based improver, but when used as a sludge dewatering agent, it shows good performance such as lowering the moisture content of sludge, forming strong flocs, and reducing the amount added.

The recommended dehydrator when the water-soluble polymer composition of the present invention is used as a sludge dewatering agent is a dehydrator in which the floc is subjected to actions such as squeezing and shearing in the initial filtration process such as a screw press and a rotary compression filter. Thus, the water-soluble polymer composition of the present invention is particularly effective for quick filterability of raw water to be treated, subsequent pressing and shearing, and effective dehydration without breaking the floc. It is.

The water-soluble polymer composition of the present invention is used for organic sludge (so-called raw sludge, surplus sludge, mixed raw sludge, digested sludge, sedimentation / floating sludge, and mixtures thereof) generated by treatment of sewage, human waste, and industrial wastewater. Usually, it is added as a 0.1-0.2% aqueous solution. The sludge targeted by the water-soluble polymer composition of the present invention is not particularly limited, but is particularly effective for sludge with a low fiber content, sludge with a high organic content (VSS / SS), and sludge with a high degree of spoilage. It is preferable.

In addition, the water-soluble polymer composition of the present invention may be used alone for sludge dehydration, but more preferable from the viewpoint of dewatering effect is a method of using in combination with an inorganic polyvalent metal salt such as iron salt or aluminum salt. It is. Examples of the inorganic polyvalent metal salt include iron salt, iron sulfate, polyiron, PAC, sulfate band, and lime. The amount of the water-soluble polymer composition of the present invention to be added to the sludge is usually 0.3-2% by mass, preferably 0.7-1.5% by mass, based on the sludge solid content. Moreover, the addition amount of the inorganic polyvalent metal salt used in combination is usually 0.2 to 0.6 mass% with respect to the sludge solid content.

The type of dehydrator used can be a normal dehydrator such as a decanter, a screw press, a belt press, or a rotary press.

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

(Example of preparation of water-soluble polymer composition) Table 1 shows the water-soluble polymer (A) having the form, composition and physical properties shown in Table 1 below, and the water-soluble amphoteric polymers (B) and (C). In addition, citric acid as an acidic substance (D) was blended in a ratio shown in Table 1 to prepare a water-soluble polymer composition. In addition, the monomer composition which comprises each water-soluble polymer is mol% with respect to the total monomer mole number, and the compounding ratio of an acidic substance (D) is represented by the weight% with respect to the total weight of a water-soluble polymer composition. ing. Further, when the water-soluble polymer (A) to be blended, the water-soluble amphoteric polymers (B) and (C) are liquid, and the water-soluble polymer composition is powder, the water-soluble polymer to be blended The soluble polymer (A), the water-soluble amphoteric polymers (B) and (C) were dried under reduced pressure for 3 hours under conditions of 50 ° C. and 50 mmHg, and then blended.

(Comparison and adjustment example of water-soluble polymer composition) A water-soluble polymer composition comprising a water-soluble polymer (A) was compared with Comparative Sample 1, water-soluble polymers (A), (B) and acidic substance (D). A water-soluble polymer composition composed of a certain citric acid is referred to as Comparative Sample 2, and a water-soluble polymer composition composed of the water-soluble polymers (A), (B) and (C) is referred to as Comparative Sample 3, and is shown in Table 1 below. The water-soluble polymer composition was prepared in the same manner as in the preparation example of the water-soluble polymer composition.

(Table 1)
EM: Water-in-oil emulsion, PW: Powder, DP: Dispersed in brine, DAC: Acrylyloxyethyltrimethylammonium chloride, DMC: Methacryloyloxyethyltrimethylammonium chloride, AC: Acrylic acid, AM: Acrylamide, MW: Weight average molecular weight, charge inclusion rate (unit:%)

(Sludge dewatering test 1) For sewage oxidation ditch surplus sludge (pH 6.23, electrical conductivity 68 mS / m, ss component weight concentration 14,300 ppm), the sludge is produced using the water-soluble polymer composition of the present invention. A dehydration test was performed. 200 mL of sludge was collected in a polycarbonate, and samples 1 and 2 in Table 1 were added to the sludge SS content 0.3%, 0.4% and 0.5% (mass% of suspended particles), respectively. The size of the generated floc was measured by performing spatula stirring 40 times. Thereafter, the mixture was filtered through a T-1179L filter cloth (made of nylon), and the filtrate amount after 10 seconds was measured. 60 seconds filtered sludge press pressure 3 Kg / m ² and dried for 1 minute, check visually filter cloth peelability, Ke - key moisture content (20 hr drying at 105 ° C.) was measured. The results are shown in Table 2.

(Comparative Test 1) Comparative Sample-1, except that the amount of the water-soluble polymer composition added was 0.4%, 0.6% and 0.8%. Tests were performed on Comparative Sample-2 and Comparative Sample-3, respectively. The results are shown in Table 2.

It is clear that Comparative Sample-1, Comparative Sample-2 and Comparative Sample-3 do not decrease the moisture content of sludge, although the amount of addition is much larger than Sample-1 and Sample-2. Moreover, it turns out that the aggregating performance has fallen extremely for the comparative sample-3 which is not mix | blending the acidic substance (D). Furthermore, it turns out that there is no difference in the sludge dehydration effect of sample-1 and sample-2 which have different product properties. That is, it shows that the water-soluble polymer (B), the water-soluble polymer (D), and the acidic substance (D) are essential.

(Table 2)
Filter cloth peelability: ○ is good, ○-is partly attached, △ is attached to half of the contact surface

(Sludge dewatering test 2) A sludge dewatering test was conducted using the water-soluble polymer composition of the present invention for sewage digested sludge (pH 6.22, electric conductivity 188 mS / m, ss weight concentration 11,800 ppm). did. 200 mL of sludge was collected in a poly-bicker, and sample-2 in Table 1 was added to the sludge SS content 0.9%, 1.1% and 1.3% (mass% of suspended particles), transferred to a beaker and stirred 20 The size of the generated floc was measured. Then, it filtered with the T-1179L filter cloth (product made from nylon), and measured the filtrate amount and filtrate state after 10 second. The sludge filtered for 60 seconds was dehydrated at a press pressure of 3 kg / m ² for 1 minute, and the cake water content (dried at 105 ° C. for 20 hours) was measured. The results are shown in Table 3.

(Comparative Test 2) Tests were performed on Comparative Sample-4, Comparative Sample-5, and Comparative Sample-6 by the same operation as the sludge dehydration test 2. The results are shown in Table 3.

Comparative Sample-4 has a poor filtrate state and a high moisture content of the dehydrated cake as compared with Sample-2. Compared with Comparative Sample-4, Comparative Sample-5 has a slightly improved liquid smoke state, but does not reach Sample-2 and has a high water content in the dehydrated cake. Furthermore, although the comparative sample-6 became a filtrate state comparable as the sample-2, it is clear that the moisture content of a dewatering cake does not fall like a sample-2. In other words, even when a water-soluble polymer (A) having a charge encapsulation rate of less than 35% and 5% or more is used, the amount of drug added can be reduced but the moisture content of the dehydrated cake is insufficiently reduced. ing.

(Table 3)
Filtrate state: ○ is missing and not visible, ○-is slightly missing

Claims (9)

Water-soluble polymer (A) having a cationic functional group having a charge inclusion ratio of 35% or more and 90% or less represented by the following (Definition 1) or (Definition 2), a water-soluble polymer having a cationic functional group and an anionic functional group Water-soluble polymer composition comprising a water-soluble polymer (C) and an acidic substance (D) having a cationic functional group and an anionic functional group having a composition ratio different from those of the water-soluble polymer (B) and (B).
(Definition 1) In the case of a water-soluble cationic polymer and an amphoteric and water-soluble amphoteric polymer having a positive difference in the copolymerization rate between a cationic monomer and an anionic monomer, the charge inclusion rate [%] = (1 −α / β) × 100
α is a titration amount obtained by titrating a water-soluble cationic polymer or an amphoteric water-soluble polymer aqueous solution adjusted to pH 4.0 with acetic acid with a potassium polyvinyl sulfonate aqueous solution. β is a water-soluble cationic polymer or an amphoteric water-soluble polymer aqueous solution adjusted to pH 4.0 with acetic acid, and an aqueous polyvinyl sulfonate potassium solution is used to neutralize the charge of the water-soluble cationic polymer or amphoteric water-soluble polymer. A titration amount obtained by adding a sufficient amount to perform, and then subtracting the titration amount titrated with an aqueous polydiallyldimethylammonium chloride solution from the blank value. Here, the blank value is a titration amount obtained by titrating a potassium polyvinylsulfonate aqueous solution with a polydiallyldimethylammonium chloride aqueous solution when no water-soluble cationic polymer or amphoteric water-soluble polymer aqueous solution was added.
(Definition 2) In the case of a water-soluble polymer that is amphoteric and has a negative difference in copolymerization rate between a cationic monomer and an anionic monomer, the charge inclusion rate [%] = (1−α / β) × 100
α is a titration amount obtained by titrating a water-soluble amphoteric polymer aqueous solution adjusted to pH 10.0 with ammonia with a polydiallyldimethylammonium chloride aqueous solution. β is a water-soluble amphoteric polymer aqueous solution adjusted to pH 10.0 with ammonia, and a polydiallyldimethylammonium chloride aqueous solution is added in an amount sufficient to neutralize the charge of the water-soluble amphoteric polymer, and then a potassium polyvinyl sulfonate aqueous solution Titration volume obtained by subtracting the titration volume titrated with the blank value. Here, the blank value is a titration amount obtained by titrating a diallyldimethylammonium chloride aqueous solution with a potassium polyvinyl sulfonate aqueous solution when no water-soluble amphoteric polymer aqueous solution was added. The water-soluble polymer (A) is a monomer represented by the following general formula (1) and / or the general formula (2) 1 mol% or more and 100 mol% or less, a single amount represented by the following general formula (3) 2. The water-soluble polymer according to claim 1, wherein the water-soluble polymer is a copolymer of a monomer mixture consisting of 0 mol% to 50 mol% of the body and 0 mol% to 99 mol% of the nonionic monomer. Composition.
General formula (1)
R ₁ is hydrogen or a methyl _group, R 2, _{R 3} and _{R 4} is an alkyl group, an alkoxy group or a benzyl group having 1 to 3 carbon atoms, it may be the same or different. A is oxygen or NH, B is an alkylene group or an alkoxylene group having 2 to 4 carbon atoms, _{X 1} ^- represents each an anion.
General formula (2)
R ₅ and R _{6 each} represent hydrogen or a methyl group, R ₇ and R ₈ each represent an alkyl group having 1 to 3 carbon atoms, an alkoxy group or a benzyl group, and X ₂ ⁻ represents an anion.
General formula (3)
R ₉ is hydrogen or CH ₂ COOY ₂ , R ₁₀ is hydrogen, methyl group or COOY ₂ , Q is SO ₃ ⁻ , C ₆ H ₄ SO ₃ ⁻ , CONHC (CH ₃ ) ₂ CH ₂ SO ₃ ⁻ , C ₆ H ₄ COO ⁻ or COO ⁻ , and Y ₁ and Y ₂ each represent hydrogen or a cation. The water-soluble polymers (B) and (C) are represented by the general formula (1) and / or the monomer represented by the general formula (2) in an amount of 1 mol% to 99 mol%, and the general formula (3). A monomer mixture comprising 1 mol% to 99 mol% of a monomer and a nonionic monomer in a range of 0 mol% to 98 mol%. The water-soluble polymer composition described in 1. The molar ratio of the cationic structural unit (a) and the anionic structural unit (b) constituting the water-soluble polymer (B) is 10 ≧ (a) / (b) ≧ 1, and the water-soluble polymer ( The molar ratio of the cationic structural unit (c) and the anionic structural unit (d) constituting C) is 1> (c) / (d) ≧ 0.1, The water-soluble polymer composition described in 1. The water-soluble polymer composition according to any one of claims 1 to 4, wherein the pH of a 0.1% by mass aqueous solution of the water-soluble polymer composition is 4.0 or less. The mass mixing ratio of the water-soluble polymer (A), the water-soluble polymer (B) and the water-soluble polymer (C) is (A) :( B) :( C) = 40 to 90: 5-55: The water-soluble polymer composition according to claim 1, wherein the water-soluble polymer composition is in the range of 5 to 55. The water-soluble polymer composition according to claim 1, comprising a powder. The water-soluble polymer (A) essentially contains a water-immiscible organic liquid in a continuous phase, a cationic monomer, and a polyfunctional monomer having a plurality of unsaturated double bonds by a surfactant. 8. The water-soluble composition according to claim 1, wherein the water-in-oil emulsion liquid obtained by emulsifying the monomer mixture aqueous solution into a dispersed phase and polymerizing the mixture is dried. 9. Polymer composition. The method for using a water-soluble polymer composition according to claim 1, wherein the water-soluble polymer composition is used as a sludge dehydrating agent.