JP2009022840A - Polymer flocculant and its application - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polymer flocculant which has an excellent solubility to water with a high mineral salt concentration when a polymer flocculant is used as an aqueous solution and which effects the high yield while assuring a high formation to the paper making system that has high mineral salt concentration in water when used as a yield improvement agent, further is very simple in a method of application and has the excellent dehydration properties to sludge with high mineral salt concentration when used as a sludge dehydration agent. <P>SOLUTION: In the polymer flocculant that is synthesized using a radical polymerizable monomer having a sulfonic acid group or phosphonic acid group or its salt (a) and a cationic radical polymerizable monomer (b) as indispensable component monomers, it is characterized by including a polymer (A) of which the copolymerization proportion of (a) is 0.01-3 mol% in the whole component monomers. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a polymer flocculant, and is particularly useful for a papermaking yield improver and a dewatering agent for wastewater treatment, and can be used in these technical fields.

  Conventionally, water-soluble polymers, particularly high-molecular-weight water-soluble polymers, have been used in various technical fields such as yield improvers and polymer flocculants.

  In the conventional papermaking process, when the stock containing filler is diluted to the final concentration to be fed into the paper machine, or after dilution, a yield improver is added to cause the pulp and filler to flow out from the paper machine into the white water. Suppress and improve yield.

As the yield improver, a water-soluble polymer such as water-soluble high molecular weight polyethylene oxide or cationic polyacrylamide is usually used.
However, the yield improver containing these water-soluble polymers needs to use a relatively large amount of the yield improver for the purpose of further improving the yield rate. It has the problem of extremely deteriorating the formation.
In order to solve this problem, a method called a dual system in which a cationic polymer and an anionic compound or polymer are used in combination has recently been highlighted. Typical examples include a method of adding an anionic inorganic compound such as bentonite after the addition of the cationic polymer (Patent Document 1), a method of adding anionic colloidal silica after the addition of the cationic polymer, and the like. (Patent Document 2).

  However, although the yield improvers described in Patent Documents 1 and 2 are relatively excellent in the balance between the yield rate and the paper texture, the level is still insufficient. Since the retention improver needs to be used in combination with two liquids, it has the problem that the method of use is complicated, such as the location of addition of each agent, the timing of addition, and the balance of the amount added in the papermaking process. there were.

On the other hand, a cationic polymer flocculant is often used alone for sludge dehydration.
However, in recent years, due to the increase in sludge generation and sludge properties, conventional cationic polymer flocculants are limited in terms of sludge throughput, dewatered cake moisture content, SS recovery rate, etc. Since the state is not always satisfactory and it is required to improve these points, various amphoteric polymer flocculants and dehydration methods using them have been studied.
For example, a sludge dehydration method in which a cation-rich amphoteric polymer flocculant having a specific ion equivalent is added to organic sludge having a pH of 5 to 8 to which an inorganic flocculant not containing inorganic sludge is added, and the pH is 5 Sludge dewatering method (Patent Document 4) using acrylate-based cationic polymer flocculant and amphoteric polymer flocculant in combination with organic sludge of ~ 8, adding inorganic flocculant to sludge, and setting pH to less than 5 , A dehydration method of adding an anion-rich amphoteric polymer flocculant having a specific composition (Patent Document 5) and an organic wastewater treatment method of sequentially adding an inorganic flocculant, an anionic polymer and a cation-rich amphoteric polymer flocculant to the wastewater (Patent Document 6) and the like are known.

However, although the above-described dewatering method has its own features, it is not always an effective method for the recent tendency of wastewater to be hardly dehydrated.
That is, since there is a demand to lower the COD value after wastewater treatment, the ratio of activated sludge treatment to wastewater is higher than before, and the sludge that performs sludge dewatering treatment contains a lot of excess sludge, In papermaking wastewater, since the fiber recovery rate in the wastewater is increasing, the fiber content in the sludge is low, and there are cases where conventional polymer flocculants and sludge dewatering methods cannot cope.

  As a flocculant that solves the problems of the yield improver and the sludge dewatering agent, the present inventors have prepared a polymer flocculant blended with two or more amphoteric polymers having different ionic structures (Patent Document 7), cation Proposed a polymer flocculant blended with two or more amphoteric polymers having different ionic structures from the hydrophilic polymer (Patent Document 8) and a polymer flocculant blended in the same way by modifying the above-mentioned polymer with a polysaccharide. (Patent Documents 9 and 10).

JP-A-4-281095 (Claims) Japanese Patent No. 2945761 (Claims) Japanese Patent Publication No. 5-56199 (Claims) Japanese Patent No. 2933627 (Claims) Japanese Patent Publication No. 6-239 (Claims) JP-A-6-134213 (Claims) International Publication No. WO03 / 08974 Pamphlet (Claims) JP-A-2004-210986 (Claims) International Publication No. WO2005 / 068552 Pamphlet (Claims) International Publication No. WO2006 / 070853 Pamphlet (Claims)

  The polymer flocculants described in Patent Documents 7 to 10 proposed by the present inventors are a one-component type yield improver, saving labor, and providing a high balance between yield rate and formation. As a sludge dewatering agent, it has an excellent dewatering effect even for sludge having a low fiber content.

When a powdery polymer is used, the polymer flocculant is dissolved in water and used as an aqueous solution.
However, when the above-mentioned polymer flocculant is dissolved in water and used, there are cases in which the solubility in water becomes insufficient or the performance as a yield improver or sludge dewatering agent becomes insufficient. . That is, as a yield improver, industrial water having an increased concentration of inorganic salts is often used in accordance with the recent increase in recovered paper recovery rate. In this case, the above-described problem has occurred. In addition, both of the yield improver and the sludge dewatering agent are commonly used, and the above-mentioned problem occurs when using hard water from abroad.
The same problem occurs when paper is manufactured using industrial water with increased concentration of inorganic salts as well as water that dissolves polymers, and when sludge prepared with hard water is used. did.

  When the polymer flocculant is used as an aqueous solution, the present inventors have found a polymer flocculant that is excellent in solubility even in water having a high inorganic salt concentration, and when used as a yield improver, High yield of paper can be achieved while ensuring high paper integrity for papermaking systems with high inorganic salt concentrations, and when used as a polymer flocculant or sludge dewatering agent, which is easy to use, inorganic In order to find a polymer flocculant having an excellent dewatering performance even for sludge with a high salt concentration, an extensive study was conducted.

As a result of various studies, the present inventors have found that a polymer obtained by copolymerizing a strongly acidic monomer in a small amount is effective in order to solve the above problems, and have completed the present invention.
Hereinafter, the present invention will be described in detail.
In the present specification, acrylate or methacrylate is represented as (meth) acrylate, acrylic acid or methacrylic acid is represented as (meth) acrylic acid, and acrylamide or methacrylamide is represented as (meth) acrylamide.

  According to the polymer flocculant of the present invention, it has excellent solubility even in water containing a large amount of inorganic salt. In addition, even when the paper stock and sludge to be applied contain a large amount of inorganic salt, the yield and formation can be improved without problems in papermaking, and sludge can be dehydrated without problems in sludge dewatering. it can.

1. Polymer (A)
The polymer (A) constituting the polymer flocculant of the present invention is a radical polymerizable monomer having a sulfonic acid group or a phosphonic acid group or a salt thereof (a) [hereinafter referred to as “monomer (a)”. ] And a cationic radical polymerizable monomer (b) [hereinafter referred to as “monomer (b)”] as an essential constituent monomer, the copolymer of (a) It is a polymer having a ratio of 0.01 to 3 mol% in all constituent monomers.
Hereinafter, each component and a manufacturing method are demonstrated.

1-1. Monomer (a)
The monomer (a) is a radical polymerizable monomer having a sulfonic acid group or a phosphonic acid group or a salt thereof.
Examples of the monomer having a sulfonic acid group include (meth) acrylamide dimethylpropane sulfonic acid, vinyl sulfonic acid, and styrene sulfonic acid. As an example of the radical polymerizable monomer having a phosphonic acid group, 2- (meth) acryloyloxyethyl acid phosphate is preferable.
The monomer salt is preferably an alkali metal salt, such as sodium salt and potassium salt, and sodium salt is preferred.
As the monomer (a), a monomer having a salt of a sulfonic acid group or a salt of a phosphonic acid group can produce a high molecular weight polymer in a short time, and there is no problem of corrosion of the polymerization apparatus. Therefore, it is preferable.
Among these, a monomer having a sulfonic acid group or a salt thereof is preferable from the viewpoint of excellent polymerization stability in the production of the polymer (A).
Further, for the same reason as described above, a monomer having a sulfonic acid group salt is more preferable.

1-2. Monomer (b)
As the monomer (b), various compounds can be used as long as they have a cationic group and have radical polymerizability.
Specifically, dialkylamino such as dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate and dimethylaminoethyl (meth) acrylate and diethylamino-2-hydroxypropyl (meth) acrylate and dimethylaminopropyl (meth) acrylate Tertiary salts such as hydrochloride and sulfate of alkyl (meth) acrylate; tertiary salts such as hydrochloride and sulfate of dialkylaminoalkyl (meth) acrylamide such as dimethylaminoethyl (meth) acrylamide; dialkylaminoalkyl (meta ) Quaternary salts such as alkyl halide adducts such as methyl chloride adduct of acrylate and aryl halide adducts such as benzyl chloride adduct, and methyl chloride addition of dialkylaminoalkyl (meth) acrylamides. Quaternary salts of aryl halide adducts such as alkyl halide adducts and benzyl chloride adducts and the like.
Among these, a quaternary salt of dialkylaminoalkyl (meth) acrylate is preferable, and a halogenated alkyl adduct of dialkylaminoalkyl (meth) acrylate is more preferable.

1-3. Other radical polymerizable monomers (c)
The polymer (A) of the present invention is produced by using the monomers (a) and (b) as essential constituent monomers. If necessary, the polymer (A) can be copolymerized with these monomers. It may be a copolymer with the monomer (c) [hereinafter referred to as “monomer (c)”].

  As the monomer (c), a nonionic radical polymerizable monomer (hereinafter referred to as “monomer (c-1)”) and an anionic radical polymerizable monomer other than the component (a) [hereinafter, "Monomer (c-2)").

As the monomer (c-1), (meth) acrylamide, dimethyl (meth) acrylamide, diethyl (meth) acrylamide and hydroxylethyl (meth) acrylate, ethylene oxide addition methoxy (meth) acrylate and ethylene oxide addition (meth) Examples include allyl ether.
Among these, (meth) acrylamide is preferable.

When the polymer (A) is an amphoteric polymer, the monomer (c-2) is copolymerized.
As the monomer (c-2), various compounds can be used as long as they have an anionic group and have radical polymerizability. Specific examples include unsaturated carboxylic acids such as (meth) acrylic acid, crotonic acid, itaconic acid and maleic acid, and salts thereof. Examples of the salt include ammonium salts, and alkali metal salts such as sodium and potassium.
Among these, (meth) acrylic acid is preferable.

  As the monomer, monomers other than those described above can be used in combination as necessary. Examples of the monomer include methoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, ethyl carbitol (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, vinyl acetate, and the like.

1-4. In the monomer / combination polymer (A), the copolymerization ratio of the monomer (a) needs to be 0.01 to 3 mol% in all the constituent monomers.
By setting the copolymerization ratio of the monomer (a) to 0.01 mol% or more, it can be excellent in solubility in water containing a large amount of inorganic salt, while it is 3 mol% or less. Thus, the resulting polymer (A) can be excellent in water solubility when used as an aqueous solution. A polymer having a copolymerization ratio of the monomer (a) exceeding 3 mol% has insufficient solubility in water.

When the monomer (a) having a strong acid group and the cationic monomer (b) are copolymerized, the strong acid group portion of the monomer (a) unit and the monomer (b) unit in the copolymer are copolymerized. It has been common knowledge that such a copolymer cannot be used in cationic polymer flocculant applications since the cationic site aggregates and the resulting copolymer becomes insoluble in water.
On the other hand, it became clear that it becomes a copolymer excellent in water solubility by carrying out the small amount copolymerization of the monomer (a) like this invention.
In addition, as will be described in detail later, the polymer (A) of the present invention is excellent in solubility even in water containing a large amount of inorganic salt.

What is necessary is just to set suitably as a copolymerization ratio of a monomer (b) according to the objective, and 5-95 mol% is preferable in all the constituent monomers.
When used as a cationic polymer flocculant, a copolymer of monomer (c-1) is preferred. In this case, the copolymerization ratio of the monomer (c-1) is preferably 5 to 95 mol% in all the constituent monomers.
When used as an amphoteric polymer flocculant, those obtained by copolymerizing monomers (c-1) and (c-2) are preferred. In this case, the copolymerization ratio of the monomers (c-1) and (c-2) may be appropriately set according to the purpose, but the monomer (c-1) is included in all the constituent monomers. 10-90 mol% and monomer (c-2) 1-40 mol% are preferable.

Preferred monomer combinations in the present invention are described below.
When used as a cationic polymer flocculant, [1] acrylamide dimethylpropane sulfonate (hereinafter referred to as “ATBS salt”) as monomer (a), and dialkylaminoalkyl acrylate as monomer (b) A copolymer consisting of acrylamide as the monomer (c-1), [2] an ATBS salt as the monomer (a), and a dialkylaminoalkyl methacrylate as the monomer (b). A tertiary salt or a copolymer comprising quaternary salt and acrylamide as the monomer (c-1), [3] ATBS salt as the monomer (a), 3 of dialkylaminoalkyl methacrylate as the monomer (b) There is a copolymer comprising quaternary salt or quaternary salt, tertiary salt or quaternary salt of dialkylaminoalkyl methacrylate and acrylamide as monomer (c-1).

  When used as an amphoteric polymer flocculant, [1] ATBS salt as monomer (a), tertiary or quaternary salt of dialkylaminoalkyl acrylate as monomer (b), monomer (c -1) is a copolymer of acrylamide and monomer (c-2) is acrylic acid, [2] is a tertiary class of ATBS salt as monomer (a) and dialkylaminoalkyl methacrylate as monomer (b) A copolymer of acrylamide as a salt or quaternary salt and monomer (c-1) and acrylic acid as monomer (c-2), [3] ATBS salt as monomer (a), single amount Tertiary or quaternary salt of dialkylaminoalkyl methacrylate as body (b), tertiary or quaternary salt of dialkylaminoalkyl methacrylate and acrylamide and monomer (c-2) as monomer (c-1) Co-weight consisting of acrylic acid as There is a body.

1-5. Production Method The production method of the polymer (A) is not particularly limited, and a general polymerization method can be employed using the above-described monomers.
For example, in the case of aqueous solution polymerization, thermal radical polymerization using potassium persulfate, ammonium persulfate, 2,2′-azobis (2-amidinopropane) dihydrochloride, a redox polymerization initiator or the like as a polymerization initiator. Or radical photopolymerization by ultraviolet irradiation using a benzoin and acetophenone type photopolymerization initiator. In the case of reverse phase emulsion polymerization, the polymerization may be carried out using a water-insoluble initiator such as azobisisobutyronitrile or benzoyl peroxide in addition to the polymerization initiator.

1-6. Processing method of the obtained polymer The polymer obtained by aqueous solution polymerization is usually gel-like, and is chopped by a known method, and at a temperature of about 60 to 150 ° C. with a band dryer, a far-infrared dryer or the like. It is dried and pulverized with a roll type pulverizer or the like to form a powdery polymer, adjusted in particle size, or added with additives.
When the polymer obtained by water-in-oil type (reverse phase) emulsion polymerization is actually used, a hydrophilic surfactant with relatively high HLB is added, diluted with water, and phase-inverted to form an oil-in-water type. Used as an emulsion.
As the polymer (A), a powdery product is preferably used.

The polymer (A) preferably has a 0.5% salt viscosity, which is an index of molecular weight, of 10 to 200 mPa · s. When used as a polymer flocculant described later, in order to achieve stable dehydration treatment Is more preferably 15 to 120 mPa · s, and particularly preferably 15 to 90 mPa · s.
In the present invention, the 0.5% salt viscosity means that a sample obtained by dissolving 0.5% of a polymer in a 4% sodium chloride aqueous solution at 25 ° C. with a B-type viscometer, rotor No. The value measured at 60 rpm using 1 or 2.

2. The polysaccharide-modified polymer (A) is a polymer obtained by polymerizing the monomers (a) and (b) in the presence of a polysaccharide [hereinafter referred to as “polymer (A-2]”). ) "] Is preferred when used as a yield improver because it is more excellent in formation.

2-1. Polysaccharides Various polysaccharides can be used in the present invention.
For example, the natural product-based polysaccharide includes starch, and specifically, potato starch, waxy potato starch, sweet potato starch, waxy corn starch, high amylose corn starch, wheat starch, rice starch, tapioca starch, sago starch , Glumannan, galactan, and the like, and raw starches such as wheat flour, corn flour, chopped and dried sweet potato, and chopped and dried tapioca.
Examples of polysaccharides other than starch include celluloses such as methylcellulose, ethylcellulose, hydroxyethylcellulose and carboxymethylcellulose, sodium alginate, gum arabic, dextran, gelatin, casein, collagen, chitin, and chitosan.

As the polysaccharide, starch is preferable, and specific examples thereof include potato starch, waxy potato starch, sweet potato starch, waxy corn starch, high amylose corn starch, wheat starch, rice starch, tapioca starch, Sago starch, gurumannan, galactan and the like are preferable.
As the starch, processed starch obtained by chemical or enzymatic modification can be used. Examples of the processing method include oxidation, esterification, etherification, and acid treatment.

  As the polysaccharide in the present invention, those obtained by cationizing or amphotericizing the above-mentioned polysaccharides by a conventional method are preferable because they are excellent in copolymerization with the monomers described later and excellent in performance as a flocculant.

The cationization of the polysaccharide may be performed according to a conventional method.
Examples of cationization include a method of treating raw material starch with a cationizing agent. Specific examples of the cationizing agent include tertiary amines such as diethylaminoethyl chloride, and quaternary ammonium salts such as 3-chloro-2-hydroxypropyltrimethylammonium chloride and glycidyltrimethylammonium chloride.
The cation substitution degree of the cationized polysaccharide is preferably 0.01 to 0.06 mass / weight% in terms of nitrogen atom, and more preferably 0.02 to 0.06 mass / weight%.

  The polysaccharide may be a polysaccharide that has been subjected to a known reaction after cationization. For example, an amphoteric polysaccharide subjected to an anionization reaction may be used. Specific examples of the anionization reaction include phosphoric acid esterification with inorganic phosphoric acid and the like; urea phosphorylation and oxidation with hypohalite and the like; carboxymethylation with monochloroacetic acid; and sulfation.

Since it is preferable to use the polysaccharide as a paste, it is preferable to use a polysaccharide that has been cooked. Here, cooking is a method in which a polysaccharide is heated to a gelatinization temperature or higher. The heating temperature in this case may be set as appropriate according to the type of starch used, but is preferably 70 ° C. or higher. Starch cooking can be carried out either batchwise or continuously.
Cooking can be performed after the cationization or simultaneously with the cationization.
As for the viscosity of the starch paste liquid to be used, the solid content concentration is preferably 10 to 40% by weight, and the value measured with a B-type viscometer at 25 ° C. is preferably 100 to 10,000 mPa · s.

The polysaccharide paste used in the present invention is preferably used in a slurry of 3 to 10% by weight diluted with water.
In addition, when the paste solution of the polysaccharide to be used is aged and solidified or becomes poorly dispersible in water, it is preferable to use a product that has been cooked before use. The cooking method in this case includes the same method as described above.

2-2. Examples of the radical polymerizable monomer used in the production of the radical polymerizable monomer polymer (A-2) include the same compounds as the monomers (a) to (c) described above. Compounds are preferred.

2-3. Production Method The polymer (A-2) is obtained by polymerizing the monomers (a) and (b) in the presence of a polysaccharide.
As a production method in this case, in the presence of a polymerization initiator and a polysaccharide, monomers (a) and (b), and if necessary, in addition to these monomers, further a monomer (c) And the like, and the like.
Hereinafter, each component to be used, polymerization method, etc. are demonstrated.

1) Ratio and combination of polysaccharide and monomer In the polymer (A-2) of the present invention, the ratio of polysaccharide to monomer is simply the total amount of polysaccharide and all monomers. The weight is preferably 50% by weight or more, more preferably 50 to 99% by weight.
When the proportion of the monomer is less than 50% by weight, the obtained polymer becomes insoluble in water, or when the obtained polymer is used as a flocculant, a high amount of polymer cannot be obtained. There is.
Examples of preferable monomer combinations in the present invention include the same combinations as described above.

2) Polymerization initiator Examples of the polymerization initiator include azo polymerization initiators, redox polymerization initiators, and photopolymerization initiators. Hereinafter, each polymerization initiator will be described.

(1) Azo polymerization initiator As the azo polymerization initiator, various compounds can be used, for example, 4,4′-azobis (4-cyanovaleric acid) (10-hour half-life temperature 69 ° C., hereinafter in parentheses) ) Have the same meaning), 2,2′-azobisisobutyronitrile (65 ° C.), 2,2′-azobis (2-methylbutyronitrile) (67 ° C.), 2,2′- Azobis [2-methyl-N- (2-hydroxyethyl) propionamide] (86 ° C.), 2,2′-azobis (2-amidinopropane) hydrochloride (56 ° C.), 2,2′-azobis [2- And (2-imidazolin-2-yl) propane] hydrochloride (44 ° C.).
The azo polymerization initiators may be used alone or in combination of two or more.

  Among the above-mentioned azo polymerization initiators, it has a high solubility in water, produces a polymer (A-2) containing no insoluble matter or a low content, a polymer having a high molecular weight (A- From the point of generating 2), the amount of unreacted monomers in the polymer (A-2) is small, and the like, a compound having a 10-hour half-life temperature of 50 ° C. or more is preferred as the azo polymerization initiator, 90 degreeC compounds are more preferable, and 50-70 degreeC compounds are still more preferable.

  The use ratio of the azo polymerization initiator is preferably 50 to 5000 ppm, more preferably 100 to 3000 ppm, and still more preferably 300 to 1000 ppm with respect to the total amount of polysaccharide and monomer. When the use ratio of the azo polymerization initiator is less than 50 ppm, the polymerization is incomplete and the residual monomer is increased. On the other hand, when it exceeds 5000 ppm, the resulting aqueous polymer becomes a low molecular weight product.

(2) Redox polymerization initiator The redox polymerization initiator is a combination of an oxidizing agent and a reducing agent.
As the oxidizing agent, a peroxide is preferable because it has a hydrogen abstraction effect of the polysaccharide and can preferably graft the monomer onto the polysaccharide. Peroxides include persulfates such as sodium persulfate, potassium persulfate and ammonium persulfate, organic peroxides such as benzoyl peroxide, t-butyl hydroperoxide, succinic peroxide, hydrogen peroxide, and bromine. Examples include sodium acid. Among these, persulfate is preferable because it is excellent in the effect of extracting hydrogen even at a low temperature at the start of polymerization.
Examples of the reducing agent include sulfites such as sodium sulfite, bisulfites such as sodium hydrogen sulfite, ascorbic acid and its salt, Rongalite, nitrous acid and its salt, triethanolamine, and cuprous sulfate.
Preferable combinations of peroxide and reducing agent include persulfate and sulfite, persulfate and bisulfite, and the like.

As a ratio of an oxidizing agent, 10-1000 ppm is preferable with respect to the total amount of a polysaccharide and a monomer, More preferably, it is 20-500 ppm, Especially preferably, it is 40-200 ppm. If this ratio is less than 10 ppm, hydrogen abstraction is insufficient. On the other hand, if it exceeds 1000 ppm, the molecular weight of the polymer (A-2) becomes small and sufficient performance may not be exhibited.
As a ratio of a reducing agent, 10-1000 ppm is preferable with respect to the total amount of a polysaccharide and a monomer, More preferably, it is 20-500 ppm.

  When a redox polymerization initiator is used, it is preferable to add an inorganic metal polymerization accelerator such as cupric chloride or ferrous chloride as a polymerization accelerator.

(3) Photopolymerization initiator As the photopolymerization initiator, there is a hydrogen abstraction effect of the polysaccharide, and a ketal-type photopolymerization initiator, an acetophenone-type photopolymerization initiator, etc. in that the monomer can be preferably grafted to the polysaccharide Is preferred. In this case, it is generated by photocleavage to generate a benzoyl radical, which functions as a hydrogen abstraction agent.
Examples of the ketal-type photopolymerization initiator include 2,2-dimethoxy-1,2-diphenylethane-1-one and benzyldimethyl ketal.
As the acetophenone type photopolymerization initiator, diethoxyacetophenone, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexyl-phenylketone, 2-methyl-2morpholino (4 -Thiomethylphenyl) propan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butane, 2-hydroxy-2-methyl-1-phenylpropan-1-one and 2- And an oligomer of hydroxy-2methyl-1- [4- (1-methylvinyl) phenyl].
In addition to these, a benzoin-type photopolymerization initiator, a thioxanthone-type photopolymerization initiator, and a photopolymerization initiator having a polyalkylene oxide group as described in JP-A-2002-097236 can also be used.

  As a ratio of a photoinitiator, 10-1000 ppm is preferable with respect to the total amount of a polysaccharide and a monomer, More preferably, it is 20-500 ppm, More preferably, it is 40-200 ppm. If this amount is less than 10 ppm, hydrogen abstraction may be insufficient or the residual monomer may increase, and if it exceeds 1000 ppm, the molecular weight of the polymer (A-2) may become small and performance may not be exhibited. .

  When a photopolymerization initiator is used, a photosensitizer such as an amine photosensitizer such as triethanolamine and methyldiethanolamine can be used in combination.

3) Polymerization type Examples of the polymerization type include aqueous solution polymerization, reverse phase suspension polymerization, reverse phase emulsion polymerization, and the like, and aqueous solution polymerization and reverse phase emulsion polymerization are preferable in terms of easy handling.

In the case of employing aqueous solution polymerization, there may be mentioned a method in which polysaccharides and monomers are dissolved or dispersed in an aqueous medium and polymerized at 10 to 100 ° C. in the presence of a polymerization initiator. The raw material polysaccharides and monomers are used by being dissolved or dispersed in water and added to an aqueous medium.
In the case of employing reversed-phase emulsion polymerization, an aqueous solution containing a polysaccharide and a monomer and an organic dispersion medium containing a hydrophobic surfactant having an HLB of 3 to 6 are stirred and mixed, and then polymerized. Examples thereof include a method of polymerizing at 10 to 100 ° C. in the presence of an initiator to obtain a water-in-oil (reverse phase) polymer emulsion. Examples of the organic dispersion medium include high-boiling hydrocarbon solvents such as mineral spirits.
The ratio of the polysaccharide and the monomer in the aqueous medium or the organic dispersion medium may be appropriately set depending on the purpose, and is preferably 20 to 70% by weight.

As a polymerization method, photopolymerization, redox polymerization, or the like may be performed according to the type of polymerization initiator used.
As a specific polymerization method, a polymerization initiator may be added to an aqueous solution containing a polysaccharide and a monomer, or to a reverse phase emulsion containing a polysaccharide and a monomer.
As the polymerization method, photopolymerization and redox polymerization can be used in combination.

  When the molecular weight is adjusted, a chain transfer agent may be used. Examples of the chain transfer agent include thiol compounds such as mercaptoethanol and mercaptopropionic acid, and reducing inorganic salts such as sodium sulfite, sodium bisulfite and sodium hypophosphite.

  In the present invention, aqueous solution polymerization is preferable. In this case, since polymerization time is particularly fast and productivity is excellent, it is preferable to perform polymerization under light irradiation.

In the case of performing light irradiation polymerization, ultraviolet light and / or visible light is used as light to be irradiated, and among these, ultraviolet light is preferable.
The intensity of light irradiation is determined in consideration of the type of monomer, the type and concentration of the photopolymerization initiator and / or photosensitizer, the molecular weight of the target polymer (A-2), the polymerization time, etc. However, generally 0.5 to 1,000 W / m ² is preferable, and 5 to 400 W / m ² is more preferable.
As the light source, for example, a fluorescent chemical lamp, a fluorescent blue lamp, a metal halide lamp, a high-pressure mercury lamp, or the like can be used.

  In the light irradiation polymerization reaction, the temperature of the aqueous monomer solution is not particularly limited. However, in order to allow the photopolymerization reaction to proceed smoothly under mild conditions, it is usually preferably 5 to 100 ° C, More preferably, the temperature is 95 ° C. The temperature at the start of the polymerization is preferably 5 to 15 ° C. in that the molecular weight of the resulting polymer (A-2) can be increased and heat removal is easy.

  The photoirradiation polymerization reaction of the aqueous monomer solution may be performed batchwise or continuously.

4) Preferred Polymerization Method As a method for producing the polymer (A-2), there is a method of polymerizing a cationic monomer and an anionic monomer in the presence of a polysaccharide, an azo polymerization initiator and a hydrogen abstracting agent. The reason why high molecular weight polymers can be grafted onto polysaccharides and the amount of residual monomers is small, and when the resulting polymer (A-2) is used as a flocculant, it has excellent aggregating performance. Is preferable.

Examples of the azo polymerization initiator include the same ones as described above.
Examples of the hydrogen abstraction agent include a redox-based hydrogen abstraction agent (hereinafter referred to as “RD abstraction agent”) and a photopolymerization initiator-based hydrogen abstraction agent (hereinafter referred to as “PT abstraction agent”). The RD abstraction agent and the PT abstraction agent function as a monomer polymerization initiator in addition to abstracting hydrogen from the polysaccharide.
As the RD abstraction agent, an oxidizing agent or the like is preferable, and specific examples include the same as described above. In this case, it is preferable to use it together with a reducing agent.
As the PT abstraction agent, a ketal type photopolymerization initiator, an acetophenone type photopolymerization initiator, and the like are preferable, and specific examples thereof include the same as those described above.

5) Treatment method of the obtained polymer The polymer obtained by the aqueous solution polymerization is converted into a powdery polymer by the same method as described above, and the particle size is adjusted, or additives are added.
The polymer obtained by water-in-oil (reverse phase) emulsion polymerization is also phase-inverted by the same method as described above and used as an oil-in-water emulsion.
As the polymer (A-2), a powdery product is preferably used.

  The polymer (A-2) preferably has a 0.5% salt viscosity of 10 to 200 mPa · s. When used as a polymer flocculant described later, in order to achieve a stable dehydration treatment, 15 The thing of -120 mPa * s is more preferable, and the thing of 15-90 mPa * s is especially preferable.

  The polymer (A-2) may be composed of a grafted polymer with a monomeric polymer grafted to a polysaccharide, but the monomeric polymer was not grafted onto the polysaccharide. A polymer may be present.

3. Polymer flocculant The polymer flocculant of the present invention contains the polymer (A) as an essential component.
As the polymer flocculant, an aqueous solution of the polymer (A) is preferable.
In this case, the water to be used is preferably applicable to water containing a large amount of inorganic salt such as hard water, specifically, water having a pH of 4 to 9 and an electric conductivity of 100 μS / cm or more. In this case, the pH is more preferably 6-9. The upper limit of electrical conductivity is preferably 10,000 μS / cm or less, more preferably 7,000 μS / cm or less.
The concentration of the polymer (A) in the aqueous solution of the polymer (A) is preferably 0.01 to 0.5% by weight, more preferably 0.01 to 0.1% by weight.

The reason why the polymer flocculant of the present invention is excellent in solubility in water containing a large amount of inorganic salt and exhibits excellent effects on paper and sludge produced using water containing a large amount of inorganic salt. The details of are unknown, but are estimated as follows.
That is, the polymer flocculant exhibits an effect as a yield improver or a sludge dewatering agent by being present in a state where the polymer chain is expanded in water. On the other hand, in water containing a large amount of inorganic salt, it is speculated that conventional polymer flocculants are aggregated due to the electrostatic influence of the inorganic salt, and the original effect cannot be sufficiently exhibited. On the other hand, the polymer (A) of the present invention has a polymer chain that does not aggregate even in water containing a large amount of inorganic salt by copolymerizing a monomer (a) that is a strong acid in a small amount. It is presumed that the polymer itself can be present and the effects inherent in the polymer can be exhibited.

  The polymer flocculant of the present invention may be a composition comprising two or more types of polymers (A). Moreover, the composition which used cationic polymer or anionic polymer together may be sufficient.

  Examples of the cationic polymer include a homopolymer of the monomer (b) described above and a copolymer of the monomer (b) and the monomer (c-1) described above.

  Examples of the anionic polymer include a homopolymer of the aforementioned monomer (c-2) and a copolymer of the aforementioned monomer (c-2) and monomer (c-1). it can.

  When a powdery polymer is used, it is preferable to add sodium hydrogen sulfate, sodium sulfate, sulfamic acid, adipic acid, citric acid, and the like. Further, as long as there is no adverse effect on the dehydration treatment, it may be used by mixing with known additives.

When the polymer flocculant of the present invention is used as a yield improver, it is preferable to use an amphoteric polymer as the polymer (A).
Furthermore, in this case, a composition comprising two or more amphoteric polymers (A) (hereinafter referred to as “blend amphoteric polymer flocculant”) and a composition comprising a cationic polymer and amphoteric polymers (A) (hereinafter referred to as “amphoteric polymers”) "Cationic amphoteric blend polymer flocculant") is preferred.
Each will be described below.

3-1. Blend amphoteric polymer flocculant The blend amphoteric polymer flocculant is particularly excellent in formation when used as a yield improver, and is therefore preferred when formation is required.
A preferable combination in this case includes, as an amphoteric polymer, two or more amphoteric polymers having different ratios of the monomer (b) and the monomers (a) and (c-2). Specifically, the amphoteric polymer (A) satisfying the following formula (1) (hereinafter referred to as “amphoteric polymer 1”) and the amphoteric polymer (A) satisfying the following formula (2) (hereinafter referred to as “amphoteric polymer”). 2 ”) or an amphoteric polymer (A) satisfying the following formulas (3) and (4) (hereinafter referred to as“ amphoteric polymer 3 ”).

[Formula 1]
Ca1 / An1 ≧ 1 (1)
[Formula 2]
Ca2 / An2 <1 (2)
[Formula 3]
Ca3 / An3 ≧ 1 (3)
[Formula 4]
│ (Ca1-An1)-(Ca3-An3) │ ≧ 1.5 (4)

[In the above formulas (1) to (4), Ca1 and An1 respectively represent the total amount of cationic monomers when the total amount of all constituent monomers in the amphoteric polymer 1 is converted to 100 mol. And the number of moles of the total anionic monomer amount, and Ca2 and An2 respectively represent the number of moles of the total cationic monomer amount and the total anionic monomer amount in the amphoteric polymer 2 as described above. , Ca3 and An3 respectively represent the number of moles of the total cationic monomer amount and the total anionic monomer amount in the amphoteric polymer 3 as described above. ]

  In this case, the amphoteric polymers 1 to 3 may be a polysaccharide-modified polymer (A-2).

The composition using the amphoteric polymer 1 and the amphoteric polymer 2 in the present invention will be described. The composition is a combination of a cation-rich amphoteric polymer 1 and an anion-rich amphoteric polymer 2.
In this case, the amphoteric polymer 1 preferably has a Ca1 / An1 of 1.5 to 10.0, and the amphoteric polymer 2 preferably has a Ca2 / An2 of 0.5 to 0.9.

Next, the composition using the amphoteric polymer 1 and the amphoteric polymer 3 in the present invention will be described. The composition uses amphoteric polymer 1 and amphoteric polymer 3 which are both cation-rich amphoteric polymers, and has a large difference between the cationic monomer unit and the anionic monomer constituting them. Small ones are used together.
In this case, Ca1 / An1 is preferably 1.2 to 40.0, and Ca3 / An3 is preferably 1.2 to 40.0.
| (Ca1-An1)-(Ca3-An3) | is preferably 1.5 to 40.0. If this value is less than 1.5, high-performance aggregation performance by blending may not be exhibited.

  The amphoteric polymers 1 to 3 can be obtained by copolymerizing a cationic monomer and an anionic monomer so as to satisfy the monomer ratio.

The composition of the present invention can be produced by mixing the amphoteric polymer 1 with the amphoteric polymer 2 or the amphoteric polymer 3. Moreover, each component can also be added separately in the sludge dehydration and papermaking processes described later.
As the amphoteric polymers 1 to 3, one type can be used, or two or more types can be used in combination, and it is simple and preferable to use one type of the amphoteric polymers 1 to 3 one by one.

The proportion of the amphoteric polymer in the composition may be appropriately set according to the purpose, but in the case of the composition comprising the amphoteric polymer 1 and 2, the amphoteric polymer 1 is 40 to 90% by weight and the amphoteric high A range of 60 to 10% by weight of molecule 2 is preferred.
In the case of the composition comprising the amphoteric polymer 1 and the amphoteric polymer 3, the amphoteric polymer 1 is preferably in the range of 10 to 90% by weight and the amphoteric polymer 3 in the range of 90 to 10% by weight.

3-2. Cationic amphoteric blend polymer flocculant The cationic amphoteric blend polymer flocculant is particularly excellent in yield when used as a yield improver, and is therefore preferred when yield is required.

In this case, the cationic polymer is a copolymer having monomers (b) and (c-1) as constituent monomer units and a copolymerization ratio of the monomer (b) of 40 mol% or less. preferable.
The amphoteric polymer is preferably a copolymer having monomers (a), (b) and (c-2) as constituent monomer units. The copolymerization ratio of the monomer in this case is as follows: monomer (a) is 0.01 to 3 mol%, monomer (b) is 10 to 50 mol%, and monomer (c-2) is 1-40 mol% is preferable.

  The ratio of the cationic polymer to the amphoteric polymer in the composition may be appropriately set according to the purpose, but the range is 10 to 90% by weight for the cationic polymer and 10 to 90% by weight for the amphoteric polymer. preferable.

4). Applications The polymer flocculant of the present invention can be applied to various applications, and can be preferably used for papermaking chemicals in papermaking processes such as sludge dehydrating agents and yield improvers.
The polymer flocculant of the present invention is particularly useful as a sludge dehydrating agent and a yield improving agent. Hereinafter, the sludge dehydrating agent and the yield improving agent will be described.

4-1. Sludge dewatering agent and sludge dewatering method When the polymer flocculant of the present invention is used as a sludge dewatering agent (hereinafter sometimes referred to as a polymer flocculant), the polymer may be in the form of powder or reversed phase emulsion. Is preferred. In actual use, when the polymer is a powder, the powder is dissolved in water and used as an aqueous solution. When the polymer is a reverse phase emulsion, it is diluted with water and phase-inverted and used as an oil-in-water emulsion.
Moreover, when using a powder thing as a sludge dehydrating agent, it is preferable to add sodium hydrogen sulfate, sodium sulfate, sulfamic acid, etc. in use. Further, as long as there is no adverse effect on the dehydration treatment, it may be used by mixing with known additives.

The sludge dewatering agent of the present invention can be applied to various sludges, and is a mixture containing organic sludge and coagulated sedimentation sludge generated in sewage, human waste, and general industrial wastewater such as food industry, chemical industry and pulp or paper industry sludge. A sludge etc. can be mentioned.
The sludge dehydrating agent of the present invention can be preferably applied particularly to sludge having a low fiber content or sludge having a high surplus ratio. Specifically, it can be preferably applied to sludge having a surplus ratio of 10 SS% or more, more preferably 20 to 50 SS%.

Specifically, the dewatering method using the sludge dewatering agent of the present invention is a method of dewatering after adding the sludge dewatering agent to the sludge.
First, a sludge dehydrating agent is added to the sludge to form a sludge floc. The flock formation method may be a known method.

  Further, if necessary, an inorganic flocculant, an organic cationic compound, a cationic polymer flocculant and an anionic polymer flocculant can be used in combination.

  Examples of the inorganic flocculant include aluminum sulfate, polyaluminum chloride, ferric chloride, ferrous sulfate, and polyiron sulfate.

  Examples of organic cationic compounds include polymer polyamines, polyamidines, and cationic surfactants.

When an inorganic flocculant or an organic cationic compound is added, it is preferable to adjust the pH to 4 to 8 because the sludge can be treated more effectively.
As a method for adjusting the pH, after adding an inorganic flocculant or an organic cationic compound, when the pH value is satisfied, pH adjustment is not particularly required, but when the range limited by the present invention is not satisfied, an acid is used. Or it adjusts by adding an alkali.
Examples of the acid include hydrochloric acid, sulfuric acid, acetic acid and sulfamic acid. Examples of the alkali include caustic soda, caustic potash, slaked lime, and ammonia.

  Examples of the cationic polymer flocculant include a homopolymer of the aforementioned cationic monomer and a copolymer of the aforementioned cationic monomer and nonionic monomer.

  Examples of the anionic polymer flocculant include a homopolymer of the aforementioned anionic monomer and a copolymer of the aforementioned anionic monomer and nonionic monomer.

  The addition ratio of the polymer flocculant to the sludge is preferably 5 to 500 ppm, and preferably 0.05 to 1% by weight with respect to SS. When the polymer flocculant and other polymer flocculants are used in combination, it is preferable that the total amount of all the polymer flocculants satisfies the addition ratio.

  The added amount of sludge dewatering agent and other flocculant, the stirring speed, the stirring time, and the like may be in accordance with conventional dewatering conditions.

  The flocs thus formed are dehydrated using a known means to obtain a dehydrated cake.

  Examples of the dehydrator include a screw press dehydrator, a belt press dehydrator, a filter press dehydrator, and a screw decanter.

The sludge dewatering agent of the present invention can also be applied to a dewatering method using a granulation concentration tank having a filtration part.
Specifically, after adding an inorganic flocculant to the sludge and further adding a sludge dewatering agent, or together with the sludge dewatering agent, the sludge is introduced into a granulation concentration tank having a filtration portion of the sludge and filtered from the filtration portion. Examples include a method of taking out the liquid and granulating, and dehydrating the granulated product with a dehydrator.

4-2. Yield improver and papermaking method When the composition of the present invention is used as a yield improver, the polymer is preferably a powder or reverse phase emulsion. In actual use, as described above, when the polymer is a powder, the powder is dissolved in water and used as an aqueous solution. When the polymer is a reversed-phase emulsion, it is diluted with water and phase-inverted. And used as an oil-in-water emulsion. In this case, the solid content in this case is preferably 0.01 to 0.5% by weight, and more preferably 0.01 to 0.1% by weight.

The paper making method using the composition of the present invention may be in accordance with a conventional method, and the paper composition may be made after adding the composition of the present invention to the paper stock.
As a method for adding the yield improver, a conventional method may be used. For example, it is added when the stock is diluted to the final concentration to be fed into the paper machine or after dilution.

As the paper material to which the yield improver is applied, it may be any material used in a normal papermaking process, and usually contains at least pulp and filler, and if necessary, additives other than filler, specifically , Sizing agent, fixing agent, paper strength enhancer, colorant and the like.
The yield improver of the present invention can be preferably applied to a pulp having a relatively high ratio of used paper such as deinked used paper in the pulp. Further, the yield improver of the present invention can be preferably applied to a papermaking system, a neutral papermaking system and a high-speed papermaking system having a high filler ratio.
Examples of the filler include clay, kaolin, agarite, talc, calcium carbonate, magnesium carbonate, lime sulfate, barium sulfate, zinc oxide, and titanium oxide. Examples of the sizing agent include acrylic acid / styrene copolymer, examples of the fixing agent include sulfuric acid band, cationic starch, and alkyl ketene dimer, and examples of the paper strength enhancer include starch and cationic or amphoteric polymer. Examples include acrylamide.

The preferred addition ratio of the yield improver is preferably 0.005 to 0.8% by weight, more preferably 0.005 to 0.5% by weight, based on the dry pulp mass in the paper stock.
The pH of the paper stock after the addition of the yield improver is preferably maintained at 5 to 10, more preferably 5 to 8. Following the addition of the yield improver, the stock is immediately fed into the paper machine.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples.
In the following, “%” means% by weight, and “part” means part by mass.

○ Production Example 1
Dimethylaminoethyl acrylate methyl chloride quaternary salt (hereinafter referred to as “DAC”) aqueous solution, acrylic acid (hereinafter referred to as “AA”) aqueous solution, acrylamide (hereinafter referred to as “AM”) aqueous solution, and acrylamide-2-methyl An aqueous solution of sodium propanesulfonate (hereinafter referred to as “ATBSNa”) was prepared by mixing each monomer with a molar ratio of DAC / AA / AM / ATBSNa = 42/5 / 52.5 / 0.5 (DAC / AA / weight ratio). AM / ATBSNa = 65.9 / 2.9 / 30.2 / 0.9) In a stainless steel reaction vessel, a total of 390 g was charged so that the solid content was 45% by weight.
Subsequently, the temperature of the solution was adjusted to 10 ° C. while blowing nitrogen gas into the solution for 60 minutes, and then 1000 ppm of azobisamidinopropane hydrochloride (hereinafter referred to as “V-50”) and sulfurous acid based on the total monomers. Sodium hydrogen is added to 5 ppm, and polymerization is carried out by irradiation for 60 minutes at an irradiation intensity of 6.0 mW / cm ² using a 100 W black light from above the reaction vessel. I got a molecule.
The obtained amphoteric polymer was taken out of the container, dried and pulverized to obtain a powdery amphoteric polymer. This amphoteric polymer is referred to as CRA-1.
The resulting polymer was measured for salt viscosity and insoluble content. The insoluble matter used the following soft water and hard water as dilution water according to the following method. The results are shown in Table 1.

[Insoluble matter measurement]
1) Take 400 ml of water in a 500 ml beaker and stir at 200 rpm with a jar tester. In addition, the following 3 types of water were used as water.
Soft water: conductivity: 75 [μS / cm], hardness: 10 [mgCaCO _{3 /} l], pH = 6.3
Hard water 1: conductivity: 210 [μS / cm], hardness: 55 [mgCaCO _{3 /} l], pH = 7.20
Hard water 2: conductivity: 1820 [μS / cm], hardness: 608 [mgCaCO _{3 /} l], pH = 8.10
2) Charge 0.40 g of the obtained amphoteric polymer into a beaker.
3) After stirring and dissolving for 2 hours, filter through an 80 mesh sieve and measure the residual volume on the sieve.

○ Production Example 2
A DAC aqueous solution, an AA aqueous solution, an AM aqueous solution and an ATBSNa aqueous solution are mixed with each monomer in a molar ratio of DAC / AA / AM / ATBSNa = 42/5 / 52.5 / 0.5 (DAC / AA / AM / by weight ratio). ATBSNa = 65.9 / 2.9 / 30.2 / 0.9) was charged to a total of 390 g in a stainless steel reaction vessel so that the solid content was 45 wt%.
Amphoteric starch slurry [Ace KT-245 manufactured by Oji Constarch Co., Ltd. Solid content: 22% or less, referred to as “KT-245”. ] Was diluted with ion-exchanged water, heated at 80 ° C. for 30 minutes and cooked to obtain an amphoteric starch slurry having a solid content of 10%. The amphoteric starch slurry was charged with 60.7 g corresponding to 3% of the total amount of monomer and starch in terms of solid content, and stirred and dispersed.
Subsequently, after adjusting the solution temperature to 10 ° C. while blowing nitrogen gas into the solution for 60 minutes, based on the solid weight of all monomers and starch, V-50 is 1000 ppm, cupric chloride is 0.1 ppm, Add ammonium persulfate to 5 ppm and sodium bisulfite to 5 ppm, and perform polymerization by irradiating with 60 W light intensity of 6.0 mW / cm ² for 60 minutes from the top of the reaction vessel. A water-soluble amphoteric polymer was obtained.
The obtained amphoteric polymer was taken out of the container and dried and pulverized under the same conditions as in Production Example 1 to obtain a powdery amphoteric polymer. This amphoteric polymer is referred to as SCRA-1.
The resulting polymer was measured for salt viscosity and insoluble content. The results are shown in Table 1.

○ Production Example 3, Comparative Production Examples 1 to 6
For Production Example 3 and Comparative Production Examples 1, 2, 4 to 6, water-soluble polymers were produced in the same manner as Production Example 1 except that the components and ratios used were changed as shown in Table 1 below.
For Comparative Production Example 3, a water-soluble polymer was produced in the same manner as in Production Example 2 except that the components and ratios used were changed as shown in Table 1 below.
About the obtained water-soluble polymer, 0.5% salt viscosity and insoluble matter were measured. The results are shown in Table 1.
The polymers of Comparative Production Example 2 (CR-2) and Comparative Production Example 5 (AR-2) in which the copolymerization ratio of the monomer (a) exceeds 3 mol% have insufficient solubility in water And cannot be used as a yield improver or sludge dehydrating agent.

* Example 1
Using CRA-1 as a yield improver, hard water with conductivity: 1820 [μS / cm], hardness: 608 [mgCaCO _{3 /} l], pH = 8.10 as dilution water, 0.05% by weight The hard water aqueous solution containing was used.
Hardwood kraft pulp is suspended in the above hard water, disaggregated and beaten, and 350 ml of 1% solids pulp slurry (hereinafter referred to as CSF) according to JIS P 8121 (hereinafter referred to as CSF) (hereinafter referred to as CSF). Raw material pulp slurry) was used.
While stirring at 1000 rpm, the following components [1] to [5] are added in this order every 10 seconds to the raw pulp slurry, and the yield (one-pass retention, hereinafter referred to as OPR) is determined by the dynamic drainage method. Was measured. In addition, the paper is made with a square bronze screen manufactured by Kumagaya Riki Kogyo Co., Ltd. so that the basis weight is 60 g / m ² using the pulp slurry after the addition of the yield improver. About the paper obtained by pressing at 100 degreeC after drying with a type | mold sheet machine press, the formation index (a numerical value is so favorable) was measured with the formation tester.

[1] Light calcium carbonate: 20% (ratio to pulp solid content in the pulp slurry. Hereinafter, simply expressed as “vs. pulp”)
[2] Sulfuric acid band: 1.7% (vs. pulp)
[3] Yield improver: 250 ppm (vs. pulp)

〇 Examples 2 to 5 and Comparative Examples 1 to 5
The performance as a yield improver was evaluated in the same manner as in Example 1 except that the yield improver shown in Tables 2 and 3 was used. The obtained results are shown in Tables 2 and 3.
As dilution water for dissolving the polymer, hard water 2 was used in Examples 1 and 5, and hard water 1 was used in Examples 2 to 4. In Comparative Examples 1 and 5, hard water 2 was used, and in Comparative Examples 2 to 4, hard water 1 was used.

From the results of Tables 2 and 3, the yield improver of the present invention is excellent in both OPR and formation, whereas in the comparative example, either the total yield or formation is insufficient. It was a thing.
If OPR decreases by 1%, for example, when producing 2 million tons of paper per year, 20,000 tons of paper stock will be collected as white water for calculation purposes.
At present, these white waters are reused through sedimentation, solid-liquid separation treatment steps, etc., but these treatments are very costly and cause papermaking line contamination.
In addition, inorganic materials such as calcium carbonate are used as raw materials in the paper stock, but if these yields are poor, they will pass through the paper-making wire operated at high speed, causing the wire to be damaged and damaged over time. become.
From the above points, in the paper manufacturing industry, even if OPR is improved by 1%, great advantages can be obtained.

  The polymer flocculant of the present invention can be used as a yield improver and a sludge dehydrating agent, and can be preferably used particularly for paper stock and sludge having a high inorganic salt content.

Claims (9)

A polymer obtained by polymerizing a radically polymerizable monomer having a sulfonic acid group or a phosphonic acid group or a salt thereof (a) and a cationic radically polymerizable monomer (b) as essential constituent monomers, A polymer flocculant containing the polymer (A) in which the copolymerization ratio of (a) is 0.01 to 3 mol% in all constituent monomers. The polymer flocculant according to claim 1, wherein the monomer (a) is a monomer having a sulfonic acid group or a salt thereof. The polymer flocculant according to claim 1 or 2, wherein the polymer (A) is a polymer obtained by polymerizing the monomers (a) and (b) in the presence of a polysaccharide. . The polymer flocculant according to any one of claims 1 to 3, which is an aqueous solution of the polymer (A). The polymer flocculant according to claim 4, wherein the aqueous solution is an aqueous solution in which the polymer (A) is dissolved in water having a pH of 4 to 9 and an electric conductivity of 100 µS / cm or more. A papermaking method in which the polymer flocculant according to any one of claims 1 to 5 is added to a paper stock. The papermaking method according to claim 6, wherein water used in the production of the stock has a pH of 4 to 9 and an electric conductivity of 100 μS / cm or more. A method for dewatering sludge that is dehydrated after adding the polymer flocculant according to any one of claims 1 to 5 to the organic sludge. The method for dewatering sludge according to claim 8, wherein the water used in the preparation of the organic sludge has a pH of 4 to 9 and an electric conductivity of 100 µS / cm or more.