JP2020165041A - Anionic yield improver and papermaking method using the same - Google Patents

Abstract

To provide an anionic yield improver capable of obtaining a high yield effect without impairing the texture in a papermaking process, and to provide a method for improving the yield of a papermaking raw material by using the anionic yield improver.SOLUTION: A water-in-oil emulsion of an anionic water-soluble polymer, which has a specific structure and composition and is produced by containing 0.5-10 mass% of an inorganic salt based on the liquid amount of the water-in-oil emulsion, is added as a yield improver to a papermaking raw material before papermaking to exhibit a high yield effect even at a low additional ratio, and the negative effect on the texture and paper quality can be suppressed.SELECTED DRAWING: None

Description

The present invention relates to a yield improver used in a papermaking process and a papermaking method using the same. Specifically, the present invention uses an anionic yield improver in a papermaking process to achieve a yield on a wire of a papermaking raw material. It is about how to improve.

In the papermaking process of coating base paper, PPC paper, high-quality paper, paperboard, newspaper paper, etc., a yield improver or yield is used to improve the yield rate on wires such as paper chemicals, fine fibers, and fillers. At the same time, a drainage improver (or a yield drainage improver) that emphasizes the function of improving drainage is used. Generally, polyacrylamide-based (PAM-based) polymers are widely used as yield improvers, but effective yield improvers and yield systems differ due to the diversification of papermaking conditions in recent years. The mainstream is cationic PAM or amphoteric PAM, but anionic PAM may be effective in some cases. Decreasing the yield rate of papermaking raw materials on the wire not only reduces productivity, but also reduces the yield of paper-making chemicals such as fillers or paper strength agents and sizing agents contained in the papermaking raw materials. It is one of the factors that cause quality deterioration. Therefore, it is necessary to apply an optimum yield improver or yield system, and efforts have been made mainly to improve the performance of cationic or amphoteric PAM. However, there are relatively few efforts to improve the performance of anionic PAM as compared with cationic or amphoteric PAM, and more effective polymers are required under the papermaking conditions in which anionic PAM is effective.
Increasing the molecular weight of anionic PAM can improve the yield rate, but it has a large effect on paper quality, especially the formation, and the addition rate is limited. Therefore, as a method for suppressing the influence on the formation, for example, Patent Document 1 describes a method for improving the yield by adding an aqueous solution having a reduced apparent viscosity of the anionic water-soluble polymer. The purpose of this method is to increase the diffusibility to paper materials and increase the yield by adding an inorganic salt or an inorganic acid to an aqueous solution in which a polymer is dissolved to reduce the apparent viscosity. However, the fact is that a large improvement in yield rate cannot be obtained as compared with the use of a polymer having a high molecular weight.
Patent Document 2 discloses cross-linked anionic or amphoteric organic polymer fine particles, and Patent Document 3 discloses a water-in-water polymer dispersion containing a crosslinked anionic polymer, and application of a papermaking additive. Is described, and its use for the purpose of improving yield is also suggested. However, although the influence on the paper quality can be relatively suppressed by these crosslinked polymers, a high yield effect cannot be obtained particularly at a low addition rate as compared with the linear polymer. Therefore, there is a demand for the development of an anionic yield improver capable of obtaining a high yield effect without damaging the texture of the paper.

Japanese Unexamined Patent Publication No. 2001-295196 Japanese Patent Application Laid-Open No. 4-226102 Special Table 2013-502502

The present invention relates to a yield improving agent used in a papermaking process and a method for improving the yield of a papermaking raw material using the same, and has a higher performance anionic yield improving agent and a yield of a papermaking raw material using the same. The challenge is to provide an improvement method.

As a result of diligent studies to solve the above problems, a water-in-oil emulsion of an anionic water-soluble polymer having a specific composition and physical properties and containing an inorganic salt was used as a yield improver as a raw material for papermaking before papermaking. It is possible to improve the yield of papermaking raw materials by using it in.

By using the water-in-oil emulsion of the anionic water-soluble polymer in the present invention as a yield improver in the papermaking raw material before papermaking, the yield is higher than that of the effective papermaking raw material of the anionic yield improving agent. The rate can be obtained, and productivity improvement and paper quality improvement can be achieved.

The anionic water-soluble polymer in the present invention contains 5 to 80 mol% of the monomer represented by the following general formula (1), 20 to 95 mol% of a copolymerizable nonionic water-soluble monomer, and an inorganic substance. An aqueous solution of a monomer mixture containing a salt is emulsified with a surfactant so that an immiscible organic liquid is in water as a continuous phase, and the aqueous solution of the monomer mixture is in a dispersed phase, polymerized, and then a phase inversion agent is added. It was manufactured by
General formula (1)
R ₁ is hydrogen, methyl group or carboxymethyl group, Q is SO ₃ , C ₆ H ₄ SO ₃ , CONHC (CH ₃ ) ₂ CH ₂ SO ₃ , C ₆ H ₄ COO or COO, R ₂ is hydrogen or COOY ₂ , Y ₁ or Y ₂ represent hydrogen or cation, respectively.

The anionic monomer used in producing the anionic water-soluble polymer in the present invention, that is, the monomer represented by the general formula (1) is in the range of 5 to 80 mol%. If it is less than 5 mol%, a large yield effect due to the anionic charge of the anionic water-soluble polymer cannot be obtained, and if it is more than 80 mol%, it becomes difficult to obtain a high molecular weight one. It is preferably in the range of 10 to 70 mol%.

Examples of the anionic monomer represented by the general formula (1) include vinyl sulfonic acid, vinyl benzene sulfonic acid, 2-acrylamide-2-methylpropane sulfonic acid, methacrylic acid, acrylic acid, itaconic acid, maleic acid, and phthalate. Acids, p-carboxystyrene acids, salts thereof, and the like can be mentioned. You may combine two or more of these.

When producing the anionic water-soluble polymer in the present invention, a cationic monomer can be used as long as the effect is not impaired. The cationic monomer used at that time is in the range of 0 to 10 mol%, and if it is more than 10 mol%, the effect as an anionic yield improver is lowered. It is preferably 5 mol% or less.

When a cationic monomer is used in the present invention, there are the following. That is, it is a quaternized product of methyl chloride or benzyl chloride such as dimethylaminoethyl (meth) acrylate or dimethylaminopropyl (meth) acrylamide. Examples are (meth) acryloyloxyethyltrimethylammonium chloride, (meth) acryloyloxy-2-hydroxypropyltrimethylammonium chloride, (meth) acryloylaminopropyltrimethylammonium chloride, (meth) acryloyloxyethyldimethylbenzylammonium. Chloride, (meth) acryloyloxy-2-hydroxypropyldimethylbenzylammonium chloride, (meth) acryloylaminopropyldimethylbenzylammonium chloride. It is also possible to combine two or more of these.

Examples of the copolymerizable nonionic monomer used in the present invention include (meth) acrylamide, N, N'-dimethylacrylamide, acrylonitrile, -2-hydroxyethyl (meth) acrylate, diacetoneacrylamide, and N-. Examples thereof include vinylpyrrolidone, N-vinylformamide, N-vinylacetamide, acrylamide and the like. You may combine two or more of these. The number of moles of the nonionic monomer is 20 to 95 mol%, preferably 30 to 90 mol%.

The anionic water-soluble polymer in the present invention can be produced by copolymerizing a monomer mixture composed of an anionic monomer and a nonionic monomer. The polymerization is carried out by a conventional water-in-oil emulsion polymerization method after preparing an aqueous solution in which these monomers are mixed.

Examples of the method for producing a water-in-oil emulsion include those listed in JP-A-55-137147, JP-A-59-130397, JP-A-10-140996, JP-A-2011-99076 and the like. It can be appropriately manufactured according to the above. A monomer mixture consisting of anionic and nonionic monomers has water, an oily substance consisting of water-immiscible hydrocarbons, an amount effective for forming a water-in-oil emulsion and an HLB. At least one type of surfactant is mixed and vigorously stirred to form a water-in-oil emulsion, which is then polymerized.

An inorganic salt is added when producing a water-in-oil emulsion of an anionic water-soluble polymer in the present invention. The timing of adding the inorganic salt is in an aqueous solution in which a monomer mixture composed of an anionic monomer and a nonionic monomer is mixed. Alternatively, an inorganic salt may be divided and a part thereof may be added to an aqueous solution mixed with a monomer mixture, and the rest may be added to a water-in-oil emulsion during or after polymerization.

The inorganic salt to be added is a salt that combines alkali metal ions such as sodium and potassium, cations such as ammonium ion and magnesium ion, and anions such as halide ion, sulfate ion, nitrate ion and phosphate ion. It can be used. The concentration of these salts is 0.5 to 10% by mass with respect to the amount of the water-in-oil emulsion. If it is not 0.5% by mass or more, the effect is difficult to be exhibited, and addition of more than 10% by mass is difficult in the manufacturing process due to the solubility of the inorganic salt, and the addition of the inorganic salt does not provide a large improvement in the yield effect.

Examples of oily substances composed of hydrocarbons used as a dispersion medium include paraffins, mineral oils such as kerosene, light oil, and medium oil, or hydrocarbons having characteristics such as boiling point and viscosity in substantially the same range as these. Synthetic oils or mixtures thereof can be mentioned. The content is in the range of 20% by mass to 50% by mass, preferably in the range of 20% by mass to 35% by mass, based on the total amount of the water-in-oil emulsion.

An example of at least one type of surfactant having an effective amount and HLB for forming a water-in-oil emulsion is a nonionic surfactant of HLB 3-11, and a specific example thereof is sorbitan monooleate. Examples thereof include sorbitan monostearate, sorbitan monopalmitate, and polyoxyethylene nonylphenyl ether. The amount of these surfactants added is 0.5 to 10% by mass, preferably 1 to 5% by mass, based on the total amount of the water-in-oil emulsion.

After the polymerization, a hydrophilic surfactant called a phase inversion agent is added to make the emulsion particles covered with the oil film more compatible with water, and the water-soluble polymer inside is easily dissolved. Dilute with and use. Examples of hydrophilic surfactants are cationic surfactants, nonionic surfactants of HLB 9 to 15, polyoxyethylene polyoxypropylene alkyl ether type, polyoxyethylene alcohol ether type and the like.

The polymerization conditions are usually appropriately determined depending on the monomer used and the copolymerized mol%, and the temperature is in the range of 20 to 80 ° C., preferably 20 to 60 ° C. A radical polymerization initiator is used to initiate polymerization. These initiators may be either oil-soluble or water-soluble, and can be polymerized by any of azo-based, redox-based, and peroxide-based initiators. Examples of oil-soluble azo-based initiators are 2,2'-azobisisobutyronitrile, dimethyl-2, 2'-azobisisobutyrate, 1,1'-azobiscyclohexanecarbonitrile, 2,2. Examples thereof include'-azobis-2-methylbutyronitrile, 2, 2'-azobis-2-methylpropionate, 4,4'-azobis- (4-methoxy-2,4-dimethyl) valeronitrile and the like.

Examples of water-soluble azo initiators are 2,2'-azobis (amidinopropane) hydride dichloride, 2,2'-azobis [2- (5-methyl-imidazolin-2-yl) propane] hydrogen chloride. Examples thereof include hydrides, 4,4'-azobis (4-cyanovaleric acid) and the like. Further, examples of the redox system include a combination of ammonium peroxodisulfite and sodium sulfite, sodium hydrogen sulfite, trimethylamine, tetramethylethylenediamine and the like. Further, examples of peroxides include ammonium peroxodisulfate or potassium, hydrogen peroxide, benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, succinic peroxide, t-butylperoxy-2-ethylhexanoate and the like. Can be mentioned.

Further, in order to adjust the degree of polymerization, it is effective to use isopropyl alcohol in combination with 0.1 to 5% by mass of the monomer, or sodium formate in combination with 0.02 to 0.5% by mass of the monomer.

The polymerization concentration of the monomer is in the range of 20 to 50% by mass, and the concentration and temperature of the polymerization are appropriately set depending on the composition of the monomer and the selection of the initiator.

Polyacrylamide-based (PAM-based) polymers, which are widely used as yield-improving agents, are made by increasing the molecular weight of PAM-based polymers in order to further improve the yield of papermaking raw materials in the wire part of the papermaking process. A method of enhancing the cross-linking and adsorbing action with pulp fibers and fillers in the raw material to improve the cohesive effect has been studied. However, as a result of causing excessive entanglement between the polymers due to the high molecular weight, the charge neutralizing action is lowered and the yield effect may not be greatly improved. It is presumed that the anionic water-soluble polymer in the present invention can obtain a high yield effect by maintaining the high molecular weight and suppressing excessive entanglement between the polymers. It is considered that the addition of the inorganic salt suppresses the entanglement, and as a result, the cross-linking adsorption action and the charge neutralization action are compatible with each other, and a high yield effect is exhibited.

The polymer structure of the anionic water-soluble polymer in the present invention can use the charge inclusion rate as an index. The charge inclusion rate used in the present invention is defined as follows.
Definition (A): Charge inclusion rate (%) = (1-α / β) × 100
α is an anionic water-soluble polymer 0.025 mass% aqueous solution adjusted to pH 10.0 with ammonia by a PCD titrator (PCD-500, AT-510) manufactured by Kyoto Denshi Kogyo Co., Ltd. Titration was performed with a 1000 N polydiallyl dimethylammonium chloride aqueous solution, a dropping rate: 0.1 ml / 5 sec, and an end point determination: 0 mV, and the titration was determined. β is sheared in a 0.0025 mass% aqueous solution of an anionic water-soluble polymer adjusted to pH 10.0 with ammonia by an ace homogenizer (AM-11) manufactured by Nippon Seiki Seisakusho Co., Ltd. at 10000 rpm for 5 minutes. In addition, similarly, the titration solution was titrated with a PCD titrator at 1/1000 N polydialyldimethylammonium chloride aqueous solution, titration rate: automatic control, end point determination: 0 mV, and the titration was obtained.
The PCD titrator is not limited to the above device as long as the same measurement can be performed, but it is necessary to specify the numerical value, and the experiment of the charge inclusion rate of the same ionic polymer measured by the above device under the above conditions. The error should be within ± 0.5%.

The titration amount α value is obtained by dropping an aqueous solution of polydiallyl dimethylammonium chloride having an opposite charge on the anionic water-soluble polymer as a sample, and then dropping the “surface” (particle-like surface portion) of the anionic water-soluble polymer. It means an operation of causing an ionic electrostatic reaction to occur in an ionic group existing in.
The titrated β value is considered to correspond to a theoretical charge amount calculated from the chemical composition of the water-soluble polymer. That is, since a large amount of countercharges appearing due to shearing are present in the water-soluble polymer, it is considered that an electrostatic neutralization reaction is performed not only on the surface charge but also on the internal charge. If the degree of cross-linking is high, α is small with respect to β, the (1-α / β) value is large, and the charge inclusion rate is large (that is, the degree of cross-linking is high).

That is, it can be said that the water-soluble polymer having a large charge inclusion rate is a water-soluble polymer having increased cross-linking, and the water-soluble polymer having a low charge inclusion rate is a water-soluble polymer having less cross-linking. The reason for this is explained as follows. In a linear water-soluble polymer, the molecule has an almost "stretched" shape in a dilute solution. On the other hand, the crosslinked water-soluble polymer has a rounded shape in the form of particles in the solution, and the ionic groups existing inside the particles are hard to appear on the outside, and the reaction with the opposite charge is slow. It is thought that it will happen.

The anionic water-soluble polymer in the present invention preferably has a charge inclusion rate in the range of 15.0% or less. In the case of a normal linear polymer or crosslinked polymer, when the polymer shrinks or entangles between the polymers, the charge existing on the surface of the polymer decreases, the charge neutralizing action is suppressed, and the yield effect decreases. There is.
When it has a branched structure or a crosslinked structure, it is considered that the branching proceeds to the intermolecular crosslinking, strong entanglement occurs, and the charge inclusion rate is high, and this value exceeds 15.0%. Further, the linear polymer also has a high molecular weight of more than 15.0%. When the charge inclusion rate is 15.0% or less, a high yield effect can be obtained even with a high molecular weight. The charge inclusion rate is preferably 10.0% or less, and even more preferably 8.0% or less.
In a linear polymer, entanglement occurs due to shrinkage of the polymer and the charge inclusion rate is high, and when branching progresses or in the region of a crosslinked polymer, stronger entanglement occurs due to cross-linking between molecules and the charge inclusion rate increases. It is thought that. On the other hand, it is presumed that the anionic water-soluble polymer in the present invention causes steric hindrance and charge repulsion due to the addition of the inorganic salt, and entanglement between the polymers is less likely to occur. In the anionic water-soluble polymer of the present invention, entanglement between the polymers is less likely to occur in the range where the charge inclusion rate is 15.0% or less, so that the behavior is similar to that of the linear polymer even if the molecular weight is high. It is considered that a high yield effect is exhibited. Further, the value of the charge inclusion rate specified in the present invention may be − (minus), but if it is 15.0% or less, it is within the range of the structure of the water-soluble polymer of the present invention and is negative in measurement. It doesn't matter. Experimentally, a water-soluble polymer having a minimum charge inclusion rate of −3.0 has been obtained, and the effect of the present invention has been confirmed.

In the anionic water-soluble polymer of the present invention, a crosslinkable monomer may be used as a structure modifier during or after the polymerization. When used, the charge inclusion rate increases as the addition rate increases, so 0.002% by mass or less is preferable with respect to the total amount of the monomers. Examples of crosslinkable monomers include N, N'-methylenebis (meth) acrylamide, triarylamine, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, and dimethacrylate. Methacrylic acid-1,3-butylene glycol, polyethylene glycol di (meth) acrylate, N-vinyl (meth) acrylamide, N-methylallylacrylamide, glycidyl acrylate, polyethylene glycol diglycidyl ether, achlorine, glioxal, vinyltrimethoxy Examples thereof include silane, and among these, N, N'-methylenebis (meth) acrylamide is preferable.

The anionic water-soluble polymer in the present invention requires a high molecular weight in order to obtain a high cohesive force. The molecular weight is expressed by the intrinsic viscosity of the water-soluble polymer constituting the water-in-oil emulsion at 0.5% by mass measured at 25 ° C. and the intrinsic viscosity in a 4% by mass aqueous saline solution is 15 to 30 dl / g. However, it is preferably in the range of 18 to 30 dl / g, more preferably 20 to 30 dl / g. If the intrinsic viscosity is lower than 15 dl / g, the yield improving effect may be significantly lowered, and if it is higher than 30 dl / g, the quality of the paper, particularly the texture may be lowered. The weight average molecular weight by the extreme viscosity method is preferably in the range of 10 million to 30 million. Further, the viscosity measured at 25 ° C. (viscosity of 0.5% by mass aqueous salt solution) when dissolved in 4% by mass saline solution so that the polymer concentration becomes 0.5% by mass can also be used as an index of molecular weight. , 0.5 mass% salt aqueous solution viscosity is preferably in the range of 150 to 350 mPa · s, more preferably 200 to 300 mPa · s.

The yield improver composed of a water-in-oil emulsion of an anionic water-soluble polymer in the present invention has an inorganic salt content, which reduces the viscosity when dissolved in water and enhances the dispersibility when added to a papermaking raw material. It is presumed that this also contributes to the improvement of performance. The high molecular weight type anionic polyacrylamide polymer used as a general anionic retention improver has a high aqueous solution viscosity, and is usually a 0.2% by mass aqueous solution B-type rotational viscometer, and the viscosity measured at 25 ° C. (Viscosity of 0.2% by mass aqueous solution) is 1000 mPa · s or more, but the water-in-oil emulsion of the anionic water-soluble polymer in the present invention adjusts the addition rate of inorganic salts even if the amount is high. By doing so, a product having a low aqueous solution viscosity can be produced. For example, even if the intrinsic viscosity is 25 dl / g or more, a 0.2 mass% aqueous solution of 800 mPa · s or less can be produced.

The yield improver composed of a water-in-oil emulsion of an anionic water-soluble polymer in the present invention is added to a papermaking raw material before papermaking. Normally, in the papermaking process, the pulp dry solid content concentration of the papermaking raw material transferred from the upstream at 2.0% by mass or more is lower than 2.0% by mass due to white water, fresh water, etc. just before the papermaking machine. It is diluted as a raw material for papermaking. Generally, it is diluted to 0.5 to 1.5% by mass, and these are called inlet raw materials and headbox raw materials, and the yield is improved with respect to these raw materials (hereinafter referred to as inlet raw materials). The agent is added and the paper is made. The yield improver of the present invention is also applied to the inlet raw material.

In the present invention, the reclaimed water emulsion of the anionic water-soluble polymer in the oil-in-oil emulsion is generally added before and after the fan pump or screen, which is a shearing process, as a conventional yield improver. The same place of addition is applied to the water-in-oil emulsion of the anionic water-soluble polymer. In order to maximize the yield rate with a small addition rate, it is preferable to add the mixture before and after the screen, which is the final shearing step. Since the effect on the formation is small even after the screen, it is possible to increase the addition rate as compared with the conventional anionic yield improver. Alternatively, it may be added separately.

The types of paper using the yield improver composed of the water-in-oil emulsion of the anionic water-soluble polymer in the present invention include newspaper paper, high-quality printing paper, medium-quality printing paper, gravure printing paper, PPC paper, and coated paper. Examples thereof include working base paper, finely coated paper, wrapping paper, liner and core base paper boarding paper. It is effective for papermaking raw materials having a relatively low anion amount, that is, a cation requirement amount. Specifically, if the cation requirement is 0.01 meq / L or less, the anionic water-soluble polymer of the present invention works effectively. Preferably, it is 0.008 meq / L or less. Further, it is effective even if the papermaking raw material exhibits cationicity (= required amount of anion). It is effective when applied to paper strength agents such as cationic or amphoteric starch, liners having a relatively large addition rate of sulfate bands, and paperboards such as core base paper. The cation requirement is Whatman No. 41 The filter paper filter solution is represented by a value (meq / L) measured with a commercially available particle charge meter (PCD-04 type manufactured by Mutec Co., Ltd.).

The yield improver composed of a water-in-oil emulsion of an anionic water-soluble polymer in the present invention can be added at the same time as a paper strength agent, a sizing agent, a sulfate band, a coagulant and other paper-making chemicals. Other cationic water-soluble polymers, amphoteric water-soluble polymers, anionic water-soluble polymers, nonionic water-soluble polymers, bentonite, colloidal silica, and the like can also be used in combination as the yield improving formulation.

Hereinafter, a yield improving agent composed of a water-in-oil emulsion of an anionic water-soluble polymer and a method for improving the yield of a papermaking raw material using the same will be specifically described below, but the present invention describes the following examples. It is not limited to.

(Example 1)
Samples 1 to 8 were prepared as a yield improver composed of a water-in-oil emulsion of an anionic water-soluble polymer in the present invention. The production was carried out by a conventional method of a water-in-oil emulsion polymerization method in which an inorganic salt was contained in an aqueous solution in which a monomer mixture was mixed at the time of polymerization. Table 1 shows these compositions and physical properties.

(Comparative Example 1) Yield improver samples 9 to 12 composed of a water-in-oil emulsion of an anionic water-soluble polymer outside the scope of the present invention were prepared by a conventional method of a water-in-oil emulsion polymerization method. Table 1 shows these compositions and physical properties. In addition, commercially available yield improver samples A to C were prepared. Table 2 shows these compositions and physical properties.

(Table 1)
AAC: Acrylic acid AAM: Acrylamide inorganic salt; SC: Sodium chloride, MS: Magnesium sulfate 0.2% by mass aqueous solution Viscosity: Measured at 25 ° C. when dissolved in water so that the polymer concentration becomes 0.2% by mass. Viscosity (mPa · s).

(Table 2)
Product form: D: Dispersed polymer solution in salt water solution, E: Water-in-oil emulsion 0.2% by mass aqueous solution Viscosity: Measured at 25 ° C. when dissolved in water so that the polymer concentration becomes 0.2% by mass. Viscosity (mPa · s).
Viscosity of 0.5 mass% salt aqueous solution: Viscosity (mPa · s) measured at 25 ° C. when dissolved in 4 mass% saline solution so that the polymer concentration becomes 0.5 mass%.

(Example 2) Using LBKP prepared to have a beating degree of 360 mL, a measurement test of the yield rate was carried out by a Brit type dynamic jar tester (using a 30 mesh wire). The LBKP paper material was diluted with fresh water and light calcium carbonate was added to prepare a paper material for adjustment. The physical property values of the adjusted paper material were: solid content concentration 9649 ppm, 41.1% by mass as Ash content such as light calcium carbonate, pH 8.9, electrical conductivity 18 mS / m, Whatman No. The cation requirement was 0.0045 meq / L and the turbidity was 34 NTU (measured with HACH 2100P type) using Mutec PCD-04 type of the 41 filter paper filter solution. A predetermined amount of the adjusting paper material was collected in a brit type dynamic jar tester, 1% by mass of cationic starch (commercially available product) was added to the solid content of the paper material, and after stirring at 1000 rpm for 20 seconds, 0 of sample 1 in Table 1 was added. . 200 ppm of 1 mass% aqueous solution was added to the solid content of the paper material (polymer pure content), and after stirring at a stirring rotation speed of 1000 rpm for 10 seconds (assuming the addition of the screen outlet in the papermaking process), the filtrate was collected and Watman No. After filtering with 41 filter paper, SS was measured, and after measuring the total yield rate, the filter paper was ashed at 525 ° C. for 2 hours, and the ash content yield rate was measured. A similar test was also performed on samples 2-7. These results are shown in Table 3.

(Comparative Example 2) The same test as in Example 2 was carried out using the same adjusting paper material as in Example 2 and using the samples in Table 1 or Table 2 outside the scope of the present invention. Further, a sample in which sodium chloride was added to a 0.1% by mass aqueous solution of sample 10 so as to be the same amount as when 1% by mass of sodium chloride was added to the amount of the water-in-oil emulsion (Sample 10-1). ) Was used to carry out the test. These results are shown in Table 3.

(Table 3)

In the example using the water-in-oil emulsion of an anionic water-soluble polymer produced by adding an inorganic salt at the time of polymerization, a higher yield effect was exhibited as compared with the case of using a sample in which the inorganic salt was not added at the time of polymerization. It was. It was confirmed that the yield effect was improved by adding the inorganic salt when the number of moles of the anionic monomer was the same as compared with the polymer containing no inorganic salt. Further, from the comparison between Sample 10 and Sample 10-1, it was confirmed that the addition of the inorganic salt to the aqueous solution did not result in a large improvement in yield, and that the inclusion of the inorganic salt during production improved the performance. In the paper material, the yield effect of sample C was lower than that of other samples, and the anionic yield improver was more effective than the cationic yield improver.

(Example 3) Using LBKP prepared to have a beating degree of 360 mL, a measurement test of the yield rate was carried out by a Brit type dynamic jar tester (using a 30 mesh wire). The LBKP paper material was diluted with fresh water and light calcium carbonate was added to prepare a paper material for adjustment. The physical property values of the adjusted paper material were: solid content concentration 10000 ppm, 41% by mass as Ash content such as light calcium carbonate, pH 8.8, electrical conductivity 17 mS / m, Whatman No. The cation requirement was 0.0061 meq / L and the turbidity was 154 NTU (measured with HACH 2100P type) using Mutec PCD-04 type of the 41 filter paper filter solution. A predetermined amount of the adjusted paper material was collected in a brit-type dynamic jar tester, 1% by mass of cationic starch (commercially available product) was added to the solid content of the paper material, and after stirring at 700 rpm for 20 seconds, 0 of sample 8 in Table 1 was added. . Add 200 ppm or 300 ppm of 1 mass% aqueous solution to the solid content of the paper (pure polymer), stir at 700 rpm for 10 seconds (assuming the addition of the screen outlet in the papermaking process), and then collect the filtrate and take a Whatman No. .. After filtering with 41 filter paper, SS was measured, and after measuring the total yield rate, the filter paper was ashed at 525 ° C. for 2 hours, and the ash content yield rate was measured. The results are shown in Table 4.

(Comparative Example 3) The same test as in Example 3 was carried out using the sample 12 in Table 1 using the same adjustment paper material as in Example 3. The results are shown in Table 4.

(Table 4)

In the example using the polymer sample 8 having 10 mol% of anionic monomer as a constituent unit, the yield effect was improved as compared with the polymer sample 12 having the same number of moles as a constituent unit. It was confirmed that when the number of moles of the anionic monomer was the same, the yield effect was improved by adding the inorganic salt as compared with the polymer containing no inorganic salt. This means that in the anionic water-soluble polymer of the present invention, the yield effect is improved by applying a polymer sample having the number of moles of anionic monomer effective for paper properties as a constituent unit. ..

(Example 4) A measurement test of the yield rate was carried out by a Brit type dynamic jar tester (using a 30 mesh wire). As a raw material, an inlet raw material (pH 8.0, electrical conductivity 112 mS / m, cation requirement 0.0024 meq / L, turbidity 10 NTU, SS 3000 ppm, Ash 990 ppm), which is a liner papermaking material for paperboard obtained from a certain paper manufacturing company, was used. .. A predetermined amount of the inlet raw material was collected in a brit type dynamic jar tester, 1% by mass of cationic starch (commercially available product) was added to the solid content of the paper material, and the mixture was stirred at 600 rpm for 30 seconds. 320 ppm of 1 mass% aqueous solution was added to the solid content of the paper material (polymer pure content), and after stirring at a stirring speed of 600 rpm for 30 seconds (assuming addition of the screen inlet in the papermaking process), the filtrate was collected and Watman No. After filtering with 41 filter paper, SS was measured, and after measuring the total yield rate, the filter paper was ashed at 525 ° C. for 2 hours, and the ash content yield rate was measured. A similar test was also performed on Sample 4. The results are shown in Table 5.

(Comparative Example 4) The same test as in Example 4 was carried out on Sample 9 using the same raw materials as in Example 4. The results are shown in Table 5.

(Table 5)

(Example 5) Using the same raw materials as in Example 4, a drainage test was carried out by a dynamic drainage tester DDA (Dynamic Drainage Analyzer, Matsubo). A predetermined amount of the raw material was put into a DDA stirring tank having a 62 mesh wire at the bottom. After stirring at a stirring rotation speed of 600 rpm for 5 seconds, 1% by mass of cationic starch (commercially available product) was added to the solid content of the paper material, and after stirring at a stirring rotation speed of 600 rpm for 30 seconds, the sample 1 shown in Table 1 was added to the inlet. After adding 320 ppm to the solid content of the raw material (pure polymer content), stirring at a stirring rotation speed of 600 rpm for 30 seconds (assuming the addition of the screen inlet), the paper material was sucked under a reduced pressure of 300 mBar to form a sheet on the wire. The drainage time and the water content of the sheet after suction for 35 seconds were measured. A similar test was also performed on Sample 4. The results are shown in Table 6.

(Comparative Example 5) The same test as in Example 5 was carried out on Sample 9 using the same raw materials as in Example 4. The results are shown in Table 6.

(Table 6)

The yield improver composed of a water-in-oil emulsion of an anionic water-soluble polymer in the present invention has an improved yield effect as compared with a conventional anionic yield improver, and further, based on the results of a water drainage test, a filter is obtained. It was confirmed that the drainage effect was excellent because the water time was shortened and the water content of the sheet was reduced.

The yield improver composed of a water-in-oil emulsion of an anionic water-soluble polymer in the present invention exhibits a high yield effect and a reclaimed water effect even at a lower addition rate than the conventional anionic yield improver. Was confirmed. By applying the yield improver in the present invention, it is possible to suppress the addition rate and reduce the influence on the formation as compared with the conventional anionic yield improver, and it is possible to improve productivity and paper quality. Can be achieved.

Claims (4)

Add 5 to 80 mol% of the monomer represented by the following general formula (1), 20 to 95 mol% of the copolymerizable nonionic water-soluble monomer, and an inorganic salt to the liquid volume of the water-in-oil emulsion. After emulsifying and polymerizing an aqueous solution of a monomer mixture containing 0.5 to 10% by mass with a surfactant so that an immiscible organic liquid is in water as a continuous phase and the aqueous solution of the monomer mixture is a dispersed phase. A yield improver consisting of a water-in-oil emulsion of an anionic water-soluble polymer produced by adding a phase inversion agent.
General formula (1)
R ₁ is hydrogen, methyl group or carboxymethyl group, Q is SO ₃ , C ₆ H ₄ SO ₃ , CONHC (CH ₃ ) ₂ CH ₂ SO ₃ , C ₆ H ₄ COO or COO, R ₂ is hydrogen or COOY ₂ , Y ₁ or Y ₂ represent hydrogen or cation, respectively. The anionic property according to claim 1, wherein the intrinsic viscosity of the anionic water-soluble polymer in a 4 mass% aqueous saline solution at 0.5 mass% measured at 25 ° C. is 15 to 30 dl / g. A yield improver consisting of a water-in-oil emulsion of a water-soluble polymer. The water-in-oil type of the anionic water-soluble polymer according to claim 1, wherein the anionic water-soluble polymer has a charge inclusion rate of 15.0% or less as measured by the following definition (A). A yield improver consisting of an emulsion.
Definition (A): Charge inclusion rate (%) = (1-α / β) × 100
α is a titration amount obtained by titrating an anionic water-soluble polymer aqueous solution adjusted to pH 10.0 with ammonia with a polydiallyldimethylammonium chloride aqueous solution. β is a titration amount obtained by shearing an anionic water-soluble polymer aqueous solution adjusted to pH 10.0 with ammonia and titrating with a polydiallyldimethylammonium chloride aqueous solution. Add 5 to 80 mol% of the monomer represented by the following general formula (1), 20 to 95 mol% of miscible nonionic water-soluble monomer and an inorganic salt to the liquid amount of the water-in-oil emulsion. On the other hand, an aqueous solution of a monomer mixture containing 0.5 to 10% by mass, an immiscible organic liquid in water with a surfactant is emulsified so as to be a continuous phase, and the aqueous solution of the monomer mixture is emulsified and polymerized. A papermaking method characterized by adding a water-in-oil emulsion of an anionic water-soluble polymer produced by adding a phase inversion agent to a papermaking raw material before papermaking.
General formula (1)
R ₁ is hydrogen, methyl group or carboxymethyl group, Q is SO ₃ , C ₆ H ₄ SO ₃ , CONHC (CH ₃ ) ₂ CH ₂ SO ₃ , C ₆ H ₄ COO or COO, R ₂ is hydrogen or COOY ₂ , Y ₁ or Y ₂ represent hydrogen or cation, respectively.