JP2007016086A - Water-soluble polymer dispersion and papermaking method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for efficiently producing a water-soluble polymer in the form of a stable dispersion exhibiting peculiar viscosity behavior by dispersion polymerization process in an aqueous salt solution in the presence of a polymeric dispersant soluble to the aqueous salt solution for the purpose of improving the function of a cationic or amphoteric water-soluble polymer as a flocculant, and to provide a papermaking method using the above water-soluble polymer. <P>SOLUTION: The water-soluble polymer is produced in the form of a stable dispersion by the dispersion polymerization process comprising conducting a copolymerization of a water-soluble monomers (mixture) consisting of a cationic water-soluble monomer and, as necessary, an anionic monomer and (meth)acrylamide and another copolymerizable nonionic water-soluble monomer in an aqueous salt solution in the presence of a polymeric dispersant soluble to the aqueous salt solution. The water-soluble polymer thus produced is ≤20 in the value of the coefficient k when the plot of reduced viscosity ηsp/c (dL/g) is approximated to the formula: ηsp/c= [η]+k×c (c is the concentration of the polymer, g/dL, and [η] is intrinsic viscosity). As a yield-improving agent and/or freeness-improving agent, this water-soluble polymer's dispersion or a diluted liquid thereof is added to a papermaking stock prior to papermaking to enable paper of good formation to be produced. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a water-soluble polymer dispersion and a papermaking method using the same. Specifically, several polymer dilutions diluted with a 1N NaCl aqueous solution to a polymer concentration of 0.1% by weight or less are obtained by capillary viscosity. A plot of reduced viscosity ηsp / c (unit: dl / g) measured at 25 ° C. using a meter is represented by the formula ηsp / c = [η] + k × c (where c is the polymer concentration, the unit is g / dl, [ η] is a water-soluble polymer having a coefficient k value of 20 or less when approximated to intrinsic viscosity), and is cationic water-soluble in a salt aqueous solution in the presence of a polymer dispersant soluble in the salt aqueous solution. A water-soluble monomer (mixture) consisting of a monomer and, if necessary, an anionic monomer, (meth) acrylamide and other nonionic water-soluble monomer copolymerizable was produced by a dispersion polymerization method. Water-soluble, characterized by being a dispersion of fine particles having a particle size of 100 μm or less Relates coalescence dispersion, also to improve the yield rate and / or drainage in papermaking raw material before papermaking purposes, also relates to a paper making method of adding a water-soluble polymer dispersion or a diluent.

Cationic or amphoteric water-soluble polymers have been applied to a wide variety of uses as flocculants. For example, it is used for solid-liquid separation in wastewater as a general water treatment agent, sludge dewatering, a yield improver in the paper industry, and as a soil solidifying agent in civil engineering.

The following are known methods for polymerizing these cationic or amphoteric water-soluble polymers. For example, the aqueous solution polymerization method is supplied as a pasty product, and the water-in-oil emulsion polymer dispersion is supplied in the form of a latex after adding a hydrophilic emulsifier called a phase inversion agent after polymerization. In many cases, the dispersion polymerization method is applied to produce a powdered product. A monomer aqueous solution with a concentration of 30 to 50% is polymerized as it is, and the gel polymer is directly granulated with a meat chopper or the like. The drying method is also applied to the production of powder products. A method of polymerizing in an aqueous salt solution has also been developed.

A water-soluble polymer dispersion prepared by a dispersion polymerization method in which a water-soluble monomer or a water-soluble monomer mixture is coexisted with an ionic polymer dispersant soluble in the aqueous salt solution is disclosed in Patent Literature 1 and the polymerization method described in Patent Document 2.

Further, in recent years, as a method for further improving the conventional performance, a crosslinked cationic or amphoteric water-soluble polymer of a water-in-oil emulsion polymer dispersion is used as a water treatment dehydrating agent, a yield improving agent in papermaking process, a drainage improving agent. Examples of effective performance have been reported. This dispersion is a dispersion obtained by polymerization by mixing a crosslinking agent in a cationic and optionally an anionic water-soluble monomer (mixture).

Japanese Patent Publication No. 4-39481 Japanese Patent Publication No. 6-51755

The present inventors paid attention to a crosslinked cationic or amphoteric water-soluble polymer in order to further upgrade the function of the cationic or amphoteric water-soluble polymer as a flocculant. A feature of the crosslinked water-soluble polymer is that it does not completely dissolve when diluted in an aqueous solution but acts as fine particles. Furthermore, it was thought that the performance would be further improved if the fine particles were made nanoscale. Accordingly, an object of the present invention is to prepare a cationic or amphoteric water-soluble polymer which becomes nanoscale fine particles when diluted in an aqueous solution by a dispersion polymerization method in the presence of a polymer dispersant soluble in the aqueous salt solution. In the case of production, it is to develop a method for producing efficiently in the state of a stable dispersion and a paper making method using the cationic or amphoteric water-soluble polymer dispersion or a diluted solution thereof.

一般式（１）
Ｒ１は水素又はメチル基、Ｒ２、Ｒ３は炭素数１〜３のアルキルあるいはアルコキシル基、Ｒ４は水素、炭素数１〜３のアルキル基、アルコキシル基あるいはベンジル基であり、同種でも異種でも良い、Ａは酸素又はＮＨ、Ｂは炭素数２〜４のアルキレン基又はアルコキシレン基、Ｘ１は陰イオンをそれぞれ表わす。

一般式（２）
Ｒ５は水素又はメチル基、Ｒ６、Ｒ７は炭素数１〜３のアルキル基、アルコキシ基あるいはベンジル基、Ｘ２は陰イオンをそれぞれ表わす。

一般式（３）
Ｒ８は水素、メチル基又はカルボキシメチル基、ＡはＳＯ３、Ｃ６Ｈ４ＳＯ３、ＣＯＮＨＣ（ＣＨ３）２ＣＨ２ＳＯ３、Ｃ６Ｈ４ＣＯＯあるいはＣＯＯ、Ｒ９は水素又はＣＯＯＹ２、Ｙ１あるいはＹ２は水素又は陽イオンを表わす。 As a result of detailed studies to solve the above problems, it has been found that a cationic or amphoteric water-soluble polymer having a specific structure having a high molecular weight can be produced by advancing the reaction under specific polymerization conditions. That is, the invention of claim 1 relates to a reduced viscosity ηsp / c (unit: unit) measured at 25 ° C. with a capillary viscometer for several polymer dilutions diluted with 1N NaCl aqueous solution to a polymer concentration of 0.1% by weight or less. The value of the coefficient k is 20 when the plot of dl / g) is approximated by the equation ηsp / c = [η] + k × c (where c is the polymer concentration, the unit is g / dl, and [η] is the intrinsic viscosity). The following water-soluble polymer, wherein the water-soluble polymer is represented by the following general formula (1) and / or (2): A monomer (mixture) comprising 0 to 50 mol% of a monomer to be prepared, (meth) acrylamide and 0 to 95 mol% of a copolymerizable nonionic water-soluble monomer in an aqueous salt solution Dispersion of fine particles having a particle size of 100 μm or less produced by a dispersion polymerization method in which a soluble polymer dispersant coexists in an aqueous solution A water-soluble polymer dispersions, characterized in that it.

General formula (1)
R1 is hydrogen or a methyl group, R2 and R3 are alkyl or alkoxyl groups having 1 to 3 carbon atoms, R4 is hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkoxyl group or a benzyl group, which may be the same or different. Represents oxygen or NH, B represents an alkylene group or alkoxylene group having 2 to 4 carbon atoms, and X1 represents an anion.

General formula (2)
R5 represents hydrogen or a methyl group, R6 and R7 each represents an alkyl group having 1 to 3 carbon atoms, an alkoxy group or a benzyl group, and X2 represents an anion.

General formula (3)
R8 represents hydrogen, a methyl group or a carboxymethyl group, A represents SO3, C6H4SO3, CONHC (CH3) 2CH2SO3, C6H4COO or COO, R9 represents hydrogen or COOY2, Y1 or Y2 represents hydrogen or a cation.

The invention according to claim 2 is the water-soluble polymer dispersion according to claim 1, wherein the water-soluble polymer is cationic.

The invention of claim 3 is the water-soluble polymer dispersion according to claim 1, wherein the water-soluble polymer is amphoteric.

The invention according to claim 4 is the water-soluble polymer dispersion according to any one of claims 1 to 3, wherein the coefficient k is 10 or less.

The invention according to claim 5 is characterized in that the intrinsic viscosity measured at 25 ° C. in a 1N NaCl aqueous solution of the water-soluble polymer constituting the water-soluble polymer dispersion is 10 to 25 dl / g. Item 5. A water-soluble polymer dispersion according to any one of Items 1 to 4.

The invention according to claim 6 is characterized in that the intrinsic viscosity measured at 25 ° C. in a 1N NaCl aqueous solution of the water-soluble polymer constituting the water-soluble polymer dispersion is 15 to 25 dl / g. Item 5. A water-soluble polymer dispersion according to any one of Items 1 to 4.

The invention according to claim 7 is the water-soluble polymer dispersion according to any one of claims 1 to 6, wherein the polymer dispersant is cationic.

The water-soluble polymer dispersion according to any one of claims 1 to 7, wherein a chain transfer agent is substantially not used when producing the dispersion polymerization method.

The invention according to claim 9 is the water-soluble polymer dispersion according to any one of claims 1 to 8 or dilution thereof in the papermaking raw material before papermaking for the purpose of improving the yield and / or drainage. A papermaking method characterized by adding a liquid.

When measuring the intrinsic viscosity of conventional cationic or amphoteric water-soluble polymers or cross-linked water-soluble polymers, several reduced viscosities are measured at different polymer concentrations in the electrolyte solution, and the concentration is extrapolated to zero. The approximate straight line of the plot usually has a positive slope (coefficient k in the above equation). However, the cationic or amphoteric water-soluble polymer of the present invention has almost no inclination, and from this, it is presumed that each polymer chain is in the form of particles on the nanoscale where there is no interaction.

The reason for this is not fully understood yet, but since the product of the present invention is precipitation polymerization in an aqueous salt solution, the polymer concentration during precipitation becomes very high. As a result, the molecule is likely to be crystallized, tends to be highly concentrated locally, and is considered to promote crystallization. Therefore, it is estimated that a part of the polymer is in a molecular form shrunken in the solution due to crystallization or other bonds. When a polymer chain in such a state is used as a yield improver in the paper industry, the papermaking raw material flocs are not enlarged and tightened to a small size, and the share is strong. Accordingly, not only the yield is improved, but also paper having a good texture can be produced.

The production method will be specifically described below. Cationic monomer used as a raw material, that is, general formula (1) and / or (2), anionic monomer as required, that is, general formula (3), (meth) acrylamide and other copolymerizable Each of the nonionic water-soluble monomers is dissolved in an aqueous salt solution. Thereafter, the polymer dispersant is added, and after substitution with nitrogen, polymerization is started with a radical polymerization initiator, and polymerization is performed while stirring.

Although the temperature at the time of superposition | polymerization changes with kinds of initiator, generally it is 5-55 degreeC. The polymerization is performed using 2,2-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride, or 4,4-azobis (4-methoxy-2,4dimethyl) valeronitrile. Azo initiators are preferred. The initiator is added in an amount of 50 to 500 ppm, preferably 70 to 200 ppm per monomer at the start of polymerization. However, since the polymerization rate is lowered by a single addition, it is preferable to add in several portions.

In addition, when copolymerizing with a redox initiator, it is difficult to control the polymerization if the polymerization is started at a temperature of 40 ° C. or higher, and a rapid increase in temperature or agglomeration of the polymerization solution occurs, resulting in a stable dispersion at a high polymerization degree. Since a liquid is not obtained, 15-35 degreeC is preferable. The initiator is added in an amount of 5 to 100 ppm, preferably 10 to 50 ppm per monomer at the start of polymerization. However, since the polymerization rate is lowered by a single addition, it is preferably added several times. As addition frequency, it is 2-5 times, Preferably it is 2-3 times.

In the case of polymerizing the cationic water-soluble polymer, examples of the cationic monomer to be used include dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylamide, and methyldiallylamine. Examples of the quaternary ammonium group-containing monomer include (meth) acryloyloxyethyltrimethylammonium chloride, (meth) acryloyl which is a quaternized product of the tertiary amino-containing monomer with methyl chloride or benzyl chloride. Oxy-2-hydroxypropyltrimethylammonium chloride, (meth) acryloylaminopropyltrimethylammonium chloride, (meth) acryloyloxyethyldimethylbenzylammonium chloride, (meth) acryloyloxy 2-hydroxypropyldimethylbenzylammonium chloride, (meta ) Acryloylaminopropyldimethylbenzylammonium chloride, dimethyldiallylammonium chloride and the like.

When the amphoteric water-soluble polymer is polymerized, in addition to the cationic monomer, an anionic monomer is used in combination. Examples thereof include vinyl sulfonic acid, vinyl benzene sulfonic acid, and 2-acrylamido 2-methylpropane sulfonic acid. Methacrylic acid, acrylic acid, itaconic acid, maleic acid or p-carboxystyrene. Furthermore, the water-soluble polymer of the present invention may be a copolymer with another nonionic monomer. For example, (meth) acrylamide, N, N-dimethylacrylamide, vinyl acetate, acrylonitrile, methyl acrylate, 2-hydroxyethyl (meth) acrylate, diacetone acrylamide, N-vinylpyrrolidone, N-vinylformamide, N-vinylacetamide The copolymerization with these 1 type (s) or 2 or more types is possible.

The composition of the monomer to be polymerized (mixture) is 5 to 100 mol% of the monomer represented by the general formula (1) and / or (2), and the monomer 0 to 0 represented by the general formula (3). Monomers (mixtures) comprising 50 mol%, (meth) acrylamide and 0 to 95 mol% of other copolymerizable nonionic water-soluble monomers are preferred. Further preferable monomer (mixture) composition is 5 to 50 mol% of the monomer represented by the general formula (1) and / or (2), and the monomer 0 to 0 represented by the general formula (3). 30 mol%, (meth) acrylamide and 50 to 95 mol% of other nonionic water-soluble monomers copolymerizable. The water-soluble polymer of the present invention has a higher function as a flocculant when the intrinsic viscosity is higher. Therefore, it is more preferable to use the (meth) acrylic monomer represented by the general formula (1) than the dimethyldiallylammonium salt represented by the general formula (2). In particular, methacryloyloxyethyltrimethylammonium chloride, acryloyloxyethyltrimethylammonium chloride or acryloyloxyethylbenzyldimethylammonium chloride is preferable, and the most preferable monomer combination is methacryloyloxyethyltrimethylammonium chloride, acryloyloxyethyl. Trimethylammonium chloride and acrylamide, or acryloyloxyethyltrimethylammonium chloride, acryloyloxyethylbenzyldimethylammonium chloride and acrylamide, or methacryloyloxyethyltrimethylammonium chloride, acryloyloxyethyltrimethylammonium chloride, acrylic acid and acrylamide In each combination .

The polymer dispersant used in the present invention can be used either ionic or nonionic, but is preferably ionic, and more preferably cationic. In the case of a cationic polymer dispersant, a (co) polymer of a cationic monomer such as (meth) acryloyloxyethyltrimethylammonium chloride or dimethyldiallylammonium chloride is used as the polymer dispersant. Copolymers of monomers and nonionic monomers can also be used. Examples of nonionic monomers include acrylamide, N-vinylformamide, N-vinylacetamide, N-vinylpyrrolidone, N, N-dimethylacrylamide, acrylonitrile, diacetone acrylamide, 2-hydroxyethyl (meth) acrylate A copolymer with acrylamide is preferred.

Nonionic polymer dispersants include polyvinylpyrrolidone, acrylamide / polyvinylcaprolactam copolymer, acrylamide / styrene copolymer, and complete amidation product of maleic anhydride / butene copolymer such as amide group and slight hydrophobicity. A water-soluble polymer having a group is also effective.

The molecular weight of these cationic polymer dispersants is 5,000 to 2,000,000, preferably 50,000 to 1,000,000. The molecular weight of the nonionic polymer dispersant is 1,000 to 100,000, preferably 1,000 to 50,000. The addition amount of these nonionic or ionic polymer dispersants is 1 to 20% by weight, preferably 5 to 15% by weight, based on the monomer.

As the salt to be used, a combination of a cation such as an alkali metal ion such as sodium or potassium or an ammonium ion and an anion such as halide ion, sulfate ion, nitrate ion or phosphate ion can be used. However, a salt with a polyvalent anion is more preferable. The salt concentration of these salts can be used from 10% by weight to a saturated concentration.

When determining the intrinsic viscosity of the product of the present invention, the reduced viscosity ηsp / c of several polymer dilutions diluted with 1N NaCl aqueous solution was measured at 25 ° C. with a capillary viscometer and plotted on the horizontal axis of concentration c. The density is extrapolated to zero, but the slope of the approximate straight line of the plot (coefficient k in the above equation) is 20 or less and there is almost no slope. Further, a polymer having a high particle property and a constant k of 10 or less is more preferable.

In general, in the dispersion polymerization method in an aqueous salt solution, the viscosity of the reaction solution may increase during the polymerization process. In order to prevent this, a chain transfer agent or the like is used. As a result, the molecular weight of the polymer may decrease. In the present invention, in order to increase the molecular weight, the polymerization is carried out by using a chain transfer agent as little as possible or substantially not at all. In order to reduce the viscosity increase during the polymerization process, water solubility is high with a high molecular weight by using techniques such as monomer addition, small amount of hydrophobic monomer, and monomer that easily salt out. It became possible to produce a polymer.

It has been found that the polymer constituting the dispersion in the salt aqueous solution of the present invention can be used as a yield improver in the paper industry when a water-soluble polymer having a high molecular weight is produced. The intrinsic viscosity of this polymer measured in 1N NaCl aqueous solution is 10-25 dl / g, more preferably 15-25 dl / g.

Since the water-soluble polymer of the present invention is precipitation polymerization in an aqueous salt solution, the polymer concentration at the time of precipitation is very high. As a result, the molecule is likely to be crystallized, tends to be highly concentrated locally, and is considered to promote crystallization. Therefore, it is estimated that a part of the polymer is a molecule contracted in the solution by crystallization or other bonds. When a polymer in such a state is used as a yield improver in the paper industry, the paper-making raw material flocs are not enlarged and tightened to a small size, which is strong in market share. Accordingly, not only the yield is improved, but also paper having a good texture can be produced. Further, it can be used in combination with one or more selected from inorganic flocculants, cationic / anionic and amphoteric water-soluble polymers.

Examples of the inorganic flocculant used in combination include aluminum sulfate, polyaluminum chloride, and polyiron sulfate. Examples of the condensed cationic water-soluble polymer among the cationic polymers include amine / epichlorohydrin condensate. Examples of anionic water-soluble polymers include homopolymers such as (meth) acrylic acid, itaconic acid, maleic acid and acrylamide 2-methylpropanesulfonic acid, or copolymers selected from two or more of the above monomers. Or a copolymer with (meth) acrylamide. An example of the amphoteric water-soluble polymer is a copolymer of a monomer mixture comprising a cationic monomer and an anionic monomer, and optionally a nonionic monomer such as (meth) acrylamide. An example of the cationic water-soluble polymer is a polymer of one or more cationic monomers or a copolymer with a nonionic monomer such as (meth) acrylamide.

Examples of the cationic monomer include dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylamide, and methyl diallylamine. Examples of the quaternary ammonium group-containing monomer include (meth) acryloyloxyethyltrimethylammonium chloride, (meth) acryloyl which is a quaternized product of the tertiary amino-containing monomer with methyl chloride or benzyl chloride. Oxy-2-hydroxypropyltrimethylammonium chloride, (meth) acryloylaminopropyltrimethylammonium chloride, (meth) acryloyloxyethyldimethylbenzylammonium chloride, (meth) acryloyloxy 2-hydroxypropyldimethylbenzylammonium chloride, (meta ) Acryloylaminopropyldimethylbenzylammonium chloride, dimethyldiallylammonium chloride and the like.

The molecular weight of the condensed cationic water-soluble polymer, anionic, cationic or amphoteric water-soluble polymer used in combination is several thousand to several hundred thousand in the case of the condensed system, and anionic, cationic or amphoteric. The water-soluble polymer is 1 million to 20 million, preferably 5 million to 15 million.

The addition amount of the water-soluble polymer of the present invention is 20 ppm to 5000 ppm, preferably 50 ppm to 1000 ppm, based on the solid content of the papermaking raw material. When used in combination, the amount of the inorganic flocculant added is 0.1 to 5%, preferably 0.5 to 3%. The addition amount of the condensed cationic aqueous polymer is 50 to 2000 ppm, preferably 50 to 500 ppm. The addition amount of the anionic, cationic or amphoteric water-soluble polymer is 20 ppm to 5000 ppm, preferably 50 ppm to 1000 ppm.

In the case of adding the water-soluble polymer of the present invention alone, the fan pump inlet, the screen inlet or the screen outlet where the papermaking raw material is diluted with white water can be considered. As a location for adding the inorganic flocculant or the condensed cationic aqueous polymer used in combination, a machine chest, a fan pump inlet, a screen inlet, or the like can be considered. Further, the addition site of the water-soluble polymer of the present invention may be a screen entrance or a screen exit. When the water-soluble polymer of the present invention is combined with an anionic, cationic or amphoteric water-soluble polymer, the water-soluble polymer of the present invention is added at the fan pump inlet or the screen inlet, anionic, cationic. The addition site of the water-soluble or amphoteric water-soluble polymer may be a screen entrance or a screen exit.

Examples of paper products to be used for improving the yield and / or drainage of the present invention include high-quality paper, medium-quality paper, newsprint paper, packaging paper, card base paper, liner, core base paper, and white balls.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples.

A 4-neck 500 ml separable flask equipped with a stirrer, reflux condenser, thermometer and nitrogen inlet tube was charged with 117.7 g of deionized water, 84.1 g of ammonium sulfate, and 80 wt% acryloyloxyethyltrimethylammonium chloride as a cationic monomer. Product (hereinafter DMQ) 17.7 g and 80% by weight acryloyloxyethyldimethylbenzylammonium chloride (hereinafter DMABC) 6.2 g, 50% by weight acrylamide (hereinafter AAM) 51.9 g, acryloyloxyethyltrimethylammonium chloride as a dispersing agent 22.5 g of a homopolymer (20% by weight liquid, viscosity 6450 mPa · s) was charged. Thereafter, nitrogen was introduced from the nitrogen introduction tube while stirring to remove dissolved oxygen. During this time, the internal temperature was adjusted to 35 ± 2 ° C. using a constant temperature water bath. 30 minutes after nitrogen introduction, 0.45 g of 1% by weight aqueous solution of 2,2′-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride as an initiator (as a monomer) 100 ppm) was added to initiate the polymerization. 0.45 g of the initiator was added after 6 hours from the start of polymerization while maintaining the internal temperature at 35 ± 2 ° C., and the reaction was further completed for 10 hours. This obtained dispersion is designated as prototype 1. The DMQ / DMABC / AAM molar ratio was 16/4/80, and the dispersion viscosity was 540 mPa · s. As a result of microscopic observation, the particles were found to be 1 to 50 μm. In addition, the reduced viscosity of each solution diluted to a polymer concentration of 0.02 g / dl, 0.04 g / dl, and 0.06 g / dl in a 1N NaCl aqueous solution using a Canon Fenceke viscometer is measured at 25 ° C. The coefficient k and the intrinsic viscosity were calculated. The results are shown in Table 1.

In the same apparatus as in Example 1, 112.2 g of deionized water, 89.3 g of ammonium sulfate, 13.5 g of 80 wt% DMQ as a cationic monomer, and 9.7 g of 80 wt% methacryloyloxyethyltrimethylammonium chloride (hereinafter DMC) 50 wt% AAM 52.9 g and acryloyloxyethyltrimethylammonium chloride homopolymer (20 wt% solution, viscosity 6450 mPa · s) 22.5 g as a dispersing agent were charged and reacted in the same manner as in Example 1. The obtained dispersion is referred to as trial production 2. The molar ratio of DMQ / DMC / AAM was 12/8/80, and the viscosity of the dispersion was 720 mPa · s. As a result of microscopic observation, the particles were found to be 1 to 50 μm. Further, the reduced viscosity was measured in the same manner as in Example 1, and the coefficient k and the intrinsic viscosity were calculated. The results are shown in Table 1.

In the same apparatus as in Example 1, 112.3 g of deionized water, 89.3 g of ammonium sulfate, 2.7 g of 60 wt% acrylic acid (hereinafter AAC), 11.2 g of 80 wt% DMQ and 80 wt% DMC 11 as cationic monomers .6 g, 50 wt.% AAM 50.9 g, and 22.5 g of acryloyloxyethyltrimethylammonium chloride homopolymer (20 wt.% Liquid, viscosity 6450 mPa · s) as a dispersing agent were charged and reacted in the same manner as in Example 1. did. The resulting dispersion is referred to as prototype 3. The molar ratio of AAC / DMQ / DMC / AAM was 5/10/10/75, and the viscosity of the dispersion was 870 mPa · s. As a result of microscopic observation, the particles were found to be 1 to 50 μm. Further, the reduced viscosity was measured in the same manner as in Example 1, and the coefficient k and the intrinsic viscosity were calculated. The results are shown in Table 1.

In the same apparatus as in Example 1, 111.9 g of deionized water, 89.3 g of ammonium sulfate, 80 wt% DMQ 16.0 g and 50 wt% AAM 37.5 g as a cationic monomer, acryloyloxyethyltrimethylammonium chloride as a dispersant 15.8 g of a homopolymer (20% by weight liquid, viscosity 6450 mPa · s) was charged. Thereafter, nitrogen was introduced from the nitrogen introduction tube while stirring to remove dissolved oxygen. During this time, the internal temperature was adjusted to 35 ± 2 ° C. using a constant temperature water bath. 30 minutes after nitrogen introduction, 0.45 g of 1% by weight aqueous solution of 2,2′-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride as an initiator (as a monomer) 100 ppm) was added to initiate the polymerization. The internal temperature was maintained at 35 ± 2 ° C., and 2 hours after the start of polymerization, 3.4 g of 80 wt% DMQ, 8.0 g of 50 wt% AAM, acryloyloxyethyltrimethylammonium chloride homopolymer as a dispersant (20 wt% liquid, viscosity 6450 mPa · s) 3.4 g of the mixture was added. After another 2 hours, a mixture of 3.4 g of 80 wt% DMQ, 8.0 g of 50 wt% AAM, and 3.4 g of acryloyloxyethyltrimethylammonium chloride homopolymer (20 wt% liquid, viscosity 6450 mPa · s) as a dispersant was added. . After 8 hours from the start of polymerization, 0.45 g of the above initiator was added, and the reaction was further completed for 10 hours. During the polymerization reaction, nitrogen was continuously introduced from the nitrogen introduction tube. This dispersion is designated as prototype 4. The DMQ / AAM molar ratio was 20/80, and the dispersion viscosity was 960 mPa · s. As a result of microscopic observation, the particles were found to be 1 to 50 μm. Further, the reduced viscosity was measured in the same manner as in Example 1, and the coefficient k and the intrinsic viscosity were calculated. The results are shown in Table 1.

(Comparative Example 1) The same monomer composition as in Example 4 was not divided and charged, and the entire amount was charged all at once to initiate polymerization. Two hours after the start of the polymerization, the viscosity of the reaction solution was remarkably increased and stirring was impossible, and the whole amount became a lump and could not be obtained as a fluid dispersion.

(Comparative Example 2) Similar to Comparative Example 1, the same monomer composition as in Example 4 was divided and charged all at once, and isopropyl alcohol as a chain transfer agent was 0.5% to the monomer. added. That is, 111.9 g of deionized water, 89.3 g of ammonium sulfate, 80 wt% DMQ 22.8 g and 50 wt% AAM 5305 g as a cationic monomer, and acryloyloxyethyltrimethylammonium chloride homopolymer (20 wt% solution, Viscosity 6450 mPa · s) 22.5 g, 0.23 g of isopropyl alcohol as a chain transfer agent were charged, and reacted in the same manner as in Example 1. The obtained dispersion is referred to as Comparative 2. The DMQ / AAM molar ratio was 20/80, and the viscosity of the dispersion was 1020 mPa · s. As a result of microscopic observation, the particles were found to be 1 to 50 μm. Further, the reduced viscosity was measured in the same manner as in Example 1, and the coefficient k and the intrinsic viscosity were calculated. The results are shown in Table 1.

(Comparative Example 3) 0.23 g (0.5% monomer) of isopropyl alcohol as a chain transfer agent was further added to the same monomer composition as in Example 1 and reacted in the same manner as in Example 1. The obtained dispersion is designated as Comparative Example 3. The DMQ / DMABC / AAM molar ratio was 16/4/80, and the dispersion viscosity was 390 mPa · s. As a result of microscopic observation, the particles were found to be 1 to 50 μm. Further, the reduced viscosity was measured in the same manner as in Example 1, and the coefficient k and the intrinsic viscosity were calculated. The results are shown in Table 1.

ＤＭＱ：アクリロイルオキシエチルトリメチルアンモニウム塩化物
ＤＭＣ：メタクリロイルオキシエチルトリメチルアンモニウム塩化物
ＡＢＣ：アクリロイルオキシエチルジメチルベンジルアンモニウム塩化物
ＡＡＣ：アクリル酸、ＡＡＭ：アクリルアミド、数値の単位 分散液粘度：ｍＰａ・ｓ、固有粘度（１規定ＮａＣｌ水溶液中）：ｄｌ／ｇ
(Table 1)

DMQ: acryloyloxyethyltrimethylammonium chloride DMC: methacryloyloxyethyltrimethylammonium chloride ABC: acryloyloxyethyldimethylbenzylammonium chloride AAC: acrylic acid, AAM: acrylamide, unit of numerical values Dispersion viscosity: mPa · s, intrinsic viscosity (In 1N NaCl aqueous solution): dl / g

Using papermaking raw materials for producing fine paper (mainly LBKP, pH 6.23, total SS content 2.37% by weight, ash content 0.41% by weight), tap water was added to a pulp concentration of 0.8% by weight. The yield was measured using a diluted, bullet type dynamic jar tester. As additive chemicals, cationic starch vs. papermaking raw material 1.0% by weight, calcium carbonate 50% by weight, neutral rosin size 0.2% by weight, sulfuric acid band 1.0% by weight, cationic and amphoteric water-soluble heavy of the present invention 0.02% by weight of the combined polymer (prototype 1 to prototype 4) or the cationic water-soluble polymer (comparative 2, 3) polymerized as a comparison is added at intervals of 15 seconds in this order, and stirring is started. After 30 seconds, white water was discharged for 10 seconds, white water was collected for 30 seconds, and the total yield was measured under the following conditions. The stirring conditions were a rotation speed of 1000 rpm, a wire 125P screen (equivalent to 200 mesh), and a total yield (SS concentration) of ADVANTEC NO. It filtered and measured by 2. After drying, the filter paper was incinerated at 525 ° C., the ash content was measured, and the yield was calculated. The measurement results are shown in Table 2.

(Table 2)

As described above, the cationic or amphoteric water-soluble polymer comprising the dispersion in the salt aqueous solution of the present invention is obtained by diluting several polymer dilutions diluted with 1N NaCl aqueous solution to a polymer concentration of 0.1% by weight or less. A plot of the reduced viscosity ηsp / c (unit: dl / g) measured at 25 ° C. with a viscometer is expressed as ηsp / c = [η] + k × c (where c is the polymer concentration, the unit is g / dl, [η ] Is a water-soluble polymer having a coefficient k value of 20 or less when approximated to an intrinsic viscosity), and it was found that the yield is improved as compared with a comparative sample having a coefficient k value of 20 or more.

The reduced viscosity ηsp / c (unit: dl / g) measured at 25 ° C. using a capillary viscometer for several polymer dilutions diluted with 1N NaCl aqueous solution to a polymer concentration of 0.1% by weight or less of the present invention. Water solubility in which the value of the coefficient k is 20 or less when the plot is approximated by the equation ηsp / c = [η] + k × c (where c is the polymer concentration, the unit is g / dl, and [η] is the intrinsic viscosity) In the production of a polymer, the water-soluble polymer is a cationic water-soluble monomer and optionally an anionic water-soluble monomer and (meth) acrylamide and other nonionic water-soluble monomers copolymerizable. A monomer (mixture) consisting of a monomer is produced by a dispersion polymerization method in a salt aqueous solution in the presence of a polymer dispersant soluble in the salt aqueous solution, and a dispersion of fine particles having a particle size of 100 μm or less is efficiently and stably produced. It can be produced in the state of a dispersed liquid. By using this dispersion for solid-liquid separation in wastewater as a general water treatment agent, dewatering of sludge, and in the paper industry, it is used as a yield improver, drainage improver, etc., and a better effect than before is expressed. Industrial value is high.

Claims (9)

A plot of reduced viscosity ηsp / c (unit: dl / g) obtained by measuring several polymer dilutions diluted with 1N NaCl aqueous solution to a polymer concentration of 0.1% by weight or less at 25 ° C. with a capillary viscometer is ηsp / C = [η] + k × c is a water-soluble polymer having a coefficient k value of 20 or less when approximated to the formula (c is the polymer concentration, the unit is g / dl, and [η] is the intrinsic viscosity). In addition, the water-soluble polymer is 5 to 100 mol% of a monomer represented by the following general formula (1) and / or (2), and a monomer 0 to 50 represented by the following general formula (3). Dispersion of a monomer (mixture) consisting of 0 to 95 mol% of mol%, (meth) acrylamide and other copolymerizable nonionic water-soluble monomers in an aqueous salt solution in the aqueous salt solution Water characterized by being a dispersion of fine particles having a particle size of 100 μm or less produced by a dispersion polymerization method in which an agent is present together Sex polymer dispersion.

General formula (1)
R1 is hydrogen or a methyl group, R2 and R3 are alkyl or alkoxyl groups having 1 to 3 carbon atoms, R4 is hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkoxyl group or a benzyl group, which may be the same or different. Represents oxygen or NH, B represents an alkylene group or alkoxylene group having 2 to 4 carbon atoms, and X1 represents an anion.

General formula (2)
R5 represents hydrogen or a methyl group, R6 and R7 each represent an alkyl group having 1 to 3 carbon atoms, an alkoxy group or a benzyl group, and X2 represents an anion.

General formula (3)
R8 represents hydrogen, a methyl group or a carboxymethyl group, A represents SO3, C6H4SO3, CONHC (CH3) 2CH2SO3, C6H4COO or COO, R9 represents hydrogen or COOY2, Y1 or Y2 represents hydrogen or a cation, respectively. The water-soluble polymer dispersion according to claim 1, wherein the water-soluble polymer is cationic. The water-soluble polymer dispersion according to claim 1, wherein the water-soluble polymer is amphoteric. The water-soluble polymer dispersion according to any one of claims 1 to 3, wherein the coefficient k of the formula is 10 or less. 5. The intrinsic viscosity measured at 25 ° C. in a 1N NaCl aqueous solution of the water-soluble polymer constituting the water-soluble polymer dispersion is 10 to 25 dl / g. The water-soluble polymer dispersion liquid described in 1. 5. The intrinsic viscosity measured at 25 ° C. in a 1 N NaCl aqueous solution of the water-soluble polymer constituting the water-soluble polymer dispersion is 15 to 25 dl / g. The water-soluble polymer dispersion liquid described in 1. The water-soluble polymer dispersion according to claim 1, wherein the polymer dispersant is cationic. The water-soluble polymer dispersion liquid according to any one of claims 1 to 7, wherein a chain transfer agent is not substantially used in the production by the dispersion polymerization method. The water-soluble polymer dispersion according to any one of claims 1 to 8 or a diluted solution thereof is added to a papermaking raw material before papermaking for the purpose of improving yield and / or drainage. Paper making method.