JP5570004B2 - Paper making method - Google Patents

Description

The present invention relates to a papermaking method capable of improving yield and improving productivity without impairing the texture in paper and board making processes.

In order to improve the yield rate of fine fibers, fillers, etc., in the paper making process of coated base paper, PPC paper, fine paper, paperboard, newsprint paper, etc., various yielding systems are used. Conventionally, as a commonly used retention agent system, there is a prescription in which a high molecular weight acrylamide-based water-soluble polymer is added before and after a fan pump or a screen which is a paper-making shear process. However, in order to maintain and improve the yield in response to changes in papermaking conditions such as an increase in the fine fiber content in the papermaking raw material and an increase in the use ratio of fine calcium carbonate as a filler, the weight average by the intrinsic viscosity method is used. A polymer having a higher molecular weight than that of a conventional product having a molecular weight in the range of 1000 to 15 million or more is required. In order to improve the yield rate, it is most effective to add a polymer after the screen, which is the final shearing step in the papermaking process, but the paper quality, especially the texture, is significantly reduced, so the addition rate is suppressed. Therefore, a significant improvement in yield cannot be expected. Therefore, a two-component retention system in which an inorganic substance or an anionic polymer is added after the screen may be used instead of a polymer single formulation. For example, an additive formulation (Patent Document 1) in which a high molecular weight cationic polymer is added before the screen and bentonite or colloidal silica is added after the screen, or a cationic polymer is added in front of the screen, and an anion after passing through the screen. Has been proposed (Patent Document 2) in which fine organic polymer fine particles are added. These are systems in which flocs broken by passing through a shearing process after the addition of the second-part cationic polymer are re-aggregated by the second-part anionic substance. However, even in these yield systems, it is necessary to increase the addition rate in order to obtain a significant improvement in the yield rate. In addition, since two liquids are used, the addition balance may need to be changed depending on the papermaking conditions, and management is complicated.
JP-A-5-239800 JP-A-2005-54311

It is an object of the present invention to provide a papermaking method for improving yield and productivity without impairing the texture in the paper and board making process.

As a result of intensive studies to solve the above problems, in the papermaking raw material before papermaking, a part of the main papermaking raw material flow that passed through the last screen is a bypass flow, and the bypass flow is further divided into two, Mixing one or more papermaking chemicals and the two split streams by mixing means;
The main paper that has passed through the last screen at the time of carrying out the paper making method for making paper after adding / mixing the paper making chemical by refluxing to one place of the main paper making raw material flow, or in the paper making raw material before paper making After a part of the raw material flow is a bypass flow, the bypass flow is further divided into three,
Two of the three divided streams and one or more papermaking chemicals are mixed by a mixing means, refluxed to one place of the main papermaking raw material stream, the remaining one divided stream and an inorganic or organic anionic property A papermaking method in which a substance solution stream or a dispersion stream is mixed by another mixing means, and added to and mixed by refluxing to one place of the main papermaking raw material stream downstream from the place where the papermaking chemical is added. In carrying out the process, one of the papermaking chemicals is a yield improver and / or a paper quality improver, and the charge inclusion rate 15 obtained by emulsion polymerization of a vinyl monomer or a vinyl monomer mixture is 15 % Or more and 90% or less of a vinyl-polymerizable crosslinkable water-soluble cationic or amphoteric polymer water-in-oil emulsion enables effective mixing of the yield improver. Improved yield without compromising reached discovered present invention that it is possible to improve the productivity.

In the papermaking process, in the papermaking process, a part of the main papermaking raw material flow that has passed through the last screen is used as a bypass flow, and the bypass flow is further divided into two, and then one or more papermaking chemicals and the two divided flows are mixed. The final screen in the papermaking raw material before or after the papermaking process, or after the addition of the papermaking chemicals and the papermaking method after making the papermaking by mixing and recirculating to one place of the main papermaking raw material flow A part of the main papermaking raw material flow that has passed through the flow is used as a bypass flow, and the bypass flow is further divided into three, and then the two of the three divided flows and one or more papermaking chemicals are mixed by a mixing means. and, the main papermaking refluxed in feed stream one location, the remaining one of the shunt and inorganic or organic anionic substance solution flow or dispersion liquid flow and the other one of the mixing means and the same mixed When the paper making method is carried out, the paper making agent is vinyl-based after the addition and mixing by refluxing to one place of the main papermaking raw material stream downstream from the place where the paper making agent is added. Uses a water-in-oil emulsion of a vinyl-polymerizable cross-linkable water-soluble cationic or amphoteric polymer with a charge inclusion rate of 15% or more and 90% or less obtained by emulsion polymerization of a monomer or vinyl monomer mixture To do.

A feature of the present invention is that a part of the papermaking raw material flow after the final shearing process before papermaking is used as a bypass flow, the bypass flow and the drug or drug dilution liquid flow are mixed, and the flow of the mixture is returned to the main papermaking raw material flow again. In addition, a highly compatible drug has been discovered in an addition method capable of efficiently mixing a papermaking raw material and a drug. As a result, a papermaking agent composed of a high molecular weight acrylamide copolymer and a papermaking raw material are efficiently mixed, and the maximum yield improvement effect or paper quality improvement effect is exhibited. Conventionally, as a chemical addition method, the primary solution of chemicals has been added to the main papermaking material stream after increasing the flow rate with secondary dilution water to lower the viscosity of the solution. It was difficult to achieve sufficient mixing because the flow rate of chemicals was very small and the flow rate was slow relative to the flow rate of the main papermaking material. Furthermore, chemicals flow along the side wall of the pipe, forming scales, causing paper breaks and dirt. However, in the addition method of the present invention, the chemicals can be mixed efficiently, and the chemicals are added after the papermaking raw material passes through the screen, so that the drawbacks of the conventional chemical addition methods can be improved.

In other words, secondary dilution water is not required, leading to savings in water usage. After passing through the screen, a yield improver and / or a paper quality improver is added, so there is little deterioration of the drug, and a small amount of drug for a large amount of papermaking raw material. Overcoming the problem of mixing, adding a part of the papermaking raw material and the drug, and adding the drug-containing liquid to the papermaking raw material, there is an advantage that the mixing of the papermaking raw material and the drug is improved. . However, since secondary dilution water is not used, the chemical viscosity is slightly higher. For this reason, a drug with good dispersibility is required. The water-in-oil emulsion of a vinyl polymerized crosslinkable water-soluble cationic or amphoteric polymer having a charge encapsulation rate of 15% or more and 90% or less used in the present invention meets this purpose.

The vinyl-polymerizable crosslinkable water-soluble cationic or amphoteric polymer of the present invention is a monomer used as a raw material, a cationic monomer, that is, a monomer represented by the general formula (2) and / or (3) 3 to 35 mol%, if necessary, an anionic monomer, that is, 0 to 50 mol% of the monomer represented by the general formula (1), a copolymerizable nonionic water-soluble monomer It can manufacture by superposing | polymerizing the aqueous solution which mixed the crosslinkable monomer in the monomer mixture which consists of 15-97 mol%. A particularly preferred form is a water-in-oil emulsion, in which the monomer aqueous solution is emulsified with a surfactant so that the water-immiscible organic liquid becomes a continuous phase and the monomer mixture aqueous solution becomes a dispersed phase. After polymerization, a phase inversion agent is added as appropriate.

Among the ionic monomers used in producing the vinyl polymerization crosslinkable water-soluble cationic or amphoteric polymer of the present invention, cationic monomers, that is, represented by the general formulas (2) and / or (3) The monomer to be used is 3 to 35 mol%, preferably 5 to 25 mol%.

The ionicity of the vinyl polymerized crosslinkable water-soluble polymer of the present invention is either cationic or amphoteric.

Among the ionic monomers used in producing the vinyl polymerization crosslinkable water-soluble cationic or amphoteric polymer used in the present invention, the cationic monomers can be exemplified as follows. That is, dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylamide, methyl diallylamine and the like can be mentioned. Examples of the quaternary ammonium group-containing monomer include methyl chloride of the tertiary amino-containing monomer. (Meth) acryloyloxyethyltrimethylammonium chloride, (meth) acryloyloxy-2-hydroxypropyltrimethylammonium chloride, (meth) acryloylaminopropyltrimethylammonium chloride, (meth) acryloyloxy, which are quaternized compounds by benzyl chloride Ethyldimethylbenzylammonium chloride, (meth) acryloyloxy-2-hydroxypropyldimethylbenzylammonium chloride, (meth) acryloylaminopropyldimethylbenzylammonium chloride, di Lil dimethyl ammonium chloride, and the like.

When the water-soluble amphoteric polymer is used, a vinyl anionic monomer is used in combination with the vinyl cationic monomer. Examples thereof include vinyl sulfonic acid, vinyl benzene sulfonic acid or 2-acrylamido-2-methylpropane sulfonic acid, methacrylic acid, acrylic acid, itaconic acid, maleic acid, phthalic acid, and p-carboxystyrene acid.

  Examples of the nonionic monomer used in producing the vinyl polymerization crosslinkable water-soluble cationic or amphoteric polymer of the present invention include (meth) acrylamide, N, N-dimethylacrylamide, acrylonitrile, (meth). Examples include 2-hydroxyethyl acrylate, diacetone acrylamide, N-vinylpyrrolidone, N-vinylformamide, N-vinylacetamide, and acryloylmorpholine.

Specific examples of the crosslinkable monomer used in the present invention include divinyl compounds such as N, N′-methylenebisacrylamide and divinylbenzene, vinyl methylol compounds such as methylolacrylamide and methylolmethacrylamide, and vinyl aldehydes such as acrolein. Among them, the use of N, N′-methylenebisacrylamide is preferable.

The crosslinkable water-soluble cationic or amphoteric polymer used in the present invention is a water-in-oil emulsion having a charge encapsulation rate of 15% or more and 90% or less. The definition of the charge inclusion rate is also defined in Japanese Patent No. 4167969, that is, the definition 1 is shown below.
Definition 1) Charge inclusion rate [%] for cationic cross-linkable water-soluble polymers and cross-linkable water-soluble polymers that are amphoteric and have a positive difference in copolymerization rate between cationic and anionic monomers = (1-α / β) × 100
α is a titration amount obtained by titrating a cross-linkable water-soluble polymer aqueous solution adjusted to pH 4.0 with acetic acid with a potassium polyvinyl sulfonate aqueous solution. β is a titration obtained by adding a sufficient amount of neutralizing charge to a crosslinkable water-soluble polymer aqueous solution adjusted to pH 4.0 with acetic acid, and then titrating with a polydiallyldimethylammonium chloride aqueous solution. Titration volume after subtracting blank value (blank value: titration volume of potassium polyvinylsulfonate aqueous solution titrated with polydiallyldimethylammonium chloride aqueous solution when no crosslinkable water-soluble polymer aqueous solution was added).
Definition 2) Charge inclusion rate [%] = (1-α / β) × 100 in the case of a cross-linkable water-soluble polymer that is amphoteric and has a negative difference in copolymerization rate between a cationic monomer and an anionic monomer
α is a titration amount obtained by titrating a crosslinkable water-soluble polymer aqueous solution adjusted to pH 10.0 with ammonia with a polydiallyldimethylammonium chloride aqueous solution. β is a titration obtained by adding a sufficient amount of polydiallyldimethylammonium chloride aqueous solution to neutralize charge to a crosslinkable water-soluble polymer aqueous solution adjusted to pH 10.0 with ammonia, and then titrating with potassium vinyl sulfonate aqueous solution. Titration amount after subtracting blank value (blank value: titration amount obtained by titrating an aqueous polydiallyldimethylammonium chloride solution with an aqueous potassium polyvinyl sulfonate solution when no 0.01% aqueous solution of a crosslinkable water-soluble polymer was added).

The vinyl polymerization type cross-linkable water-soluble cationic or amphoteric polymer of the present invention has a charge inclusion ratio in the range of 15% to 90%, preferably in the range of 35 to 90%. When the crosslinkable water-soluble ionic polymer is added to the papermaking raw material, it adsorbs to the suspended particles and acts as an adhesive between the particles, resulting in aggregation of the particles. At this time, the crosslinkable water-soluble ionic polymer has a “density-packed” molecular form, so it binds to the particle surface at multiple points, and by adjusting the amount added, it is more tight and relatively strong floc. Is estimated to form. The result is a small size but hard to break flock, which has a positive effect on the paper texture. In addition, it is considered that the crosslinkable polymer has properties close to particles when the degree of crosslinking is high, and is more smoothly dispersed in the papermaking raw material than the linear water-soluble ionic polymer. As a result, papermaking can be performed without any trouble even if it is added after passing through the final screen. What can be used for such a purpose is a charge inclusion ratio in the range of 15% or more and 90% or less, preferably 35 to 90%.

Regarding the method for measuring the charge inclusion rate, a cationic cross-linkable water-soluble polymer and a cross-linkable water-soluble polymer that is amphoteric and has a positive difference in the copolymerization rate between a cationic monomer and an anionic monomer Then, it is calculated as follows.
Charge inclusion rate [%] = (1−α / β) × 100
α is a 0.01% aqueous solution of a crosslinkable water-soluble polymer 0.01% aqueous solution adjusted to pH 4.0 with acetic acid by a PCD titration device (Mutek PCD-03, Mutek PCD-Two Titortor Version 2) manufactured by Mutech. This is a titration amount obtained by titration with an aqueous potassium sulfonate solution, dropping rate: 0.05 ml / 10 sec, and end point determination: 0 mV. β is added to a 0.01% aqueous solution of a crosslinkable water-soluble polymer adjusted to pH 4.0 with acetic acid in an amount sufficient to neutralize the charge with a 1 / 400N aqueous potassium polyvinyl sulfonate solution, and stirred sufficiently. Using a PCD titrator, titration is performed with a drop solution: 1 / 1000N polydiallyldimethylammonium chloride aqueous solution, drop rate: 0.05 ml / 10 sec, end point determination: 0 mV, and this titration value is subtracted from the blank value. The blank value means that a potassium polyvinyl sulfonate aqueous solution having the same concentration as that of the above sample adjusted to pH 4.0 with acetic acid is similarly added by a PCD titration apparatus using a dropping solution: 1 / 1000N polydiallyldimethylammonium chloride aqueous solution, dropping rate: 0.00. 05 ml / 10 sec, end point determination: titration at 0 mV.

For a crosslinkable water-soluble polymer that is amphoteric and has a negative difference in copolymerization rate between a cationic monomer and an anionic monomer, the calculation is performed as follows.
Charge inclusion rate [%] = (1−α / β) × 100
α is a 0.01% aqueous solution of a cross-linkable water-soluble polymer adjusted to pH 10.0 with ammonia by using a PCD titration apparatus (Mutek PCD-03, Mutek PCD-Two Titortor Version 2) manufactured by Mutech. This is a titration amount obtained by titration with a diallyldimethylammonium chloride aqueous solution, a dropping speed: 0.05 ml / 10 sec, and an end point determination: 0 mV. β is added to a 0.01% aqueous solution of a crosslinkable water-soluble polymer adjusted to pH 10.0 with ammonia, and a 1 / 400N polydiallyldimethylammonium chloride aqueous solution is added in an amount sufficient for charge neutralization, and sufficiently stirred. Similarly, titrate with a PCD titrator at a dropping solution: 1 / 1000N potassium polyvinyl sulfonate aqueous solution, dropping rate: 0.05 ml / 10 sec, end point determination: 0 mV, and subtract this titration value from the blank value. The blank value is a polydiallyldimethylammonium chloride aqueous solution having the same concentration as that of the sample adjusted to pH 10.0 with ammonia in the same manner, using a PCD titrator, dropping solution: 1/1000 N potassium polyvinylsulfonate aqueous solution, dropping rate: 0.00. 05 ml / 10 sec, end point determination: titration at 0 mV.

The vinyl polymerization crosslinkable water-soluble cationic or amphoteric polymer of the present invention is produced by copolymerizing a monomer mixture comprising an ionic monomer and a nonionic monomer and a crosslinkable monomer. be able to. Polymerization can be carried out by an ordinary polymerization method after preparing an aqueous solution in which these monomers are mixed.

As the polymerization method, after polymerization by aqueous solution polymerization, water-in-oil emulsion polymerization, water-in-oil dispersion polymerization, salt water dispersion polymerization, etc., it can be made into any product form such as aqueous solution, dispersion, emulsion or powder. . A preferred form is a water-in-oil emulsion polymerized product having a high concentration and a short dissolution time.

As a method for producing a water-in-oil emulsion, a monomer mixture comprising an ionic monomer and a nonionic monomer and a crosslinkable monomer is water, and an oil comprising at least a water-immiscible hydrocarbon. A method of synthesizing by mixing a substance, an effective amount for forming a water-in-oil emulsion, and at least one surfactant having HLB, and vigorously stirring to form a water-in-oil emulsion, followed by polymerization It is.

Examples of oily substances made 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 may be mentioned. As content, it is the range of 20 mass%-50 mass% with respect to the water-in-oil type emulsion whole quantity, Preferably it is the range of 20 mass%-35 mass%.

Examples of at least one surfactant having an amount effective to form a water-in-oil emulsion and HLB are HLB 3-11 nonionic surfactants, specific examples of which include sorbitan monooleate, Examples include sorbitan monostearate and sorbitan monopalmitate. The amount of these surfactants to be 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 easy to adjust to water, and the water-soluble polymer therein is easily dissolved. Dilute with and use for each application. Examples of hydrophilic surfactants are cationic surfactants and HLB 9-15 nonionic surfactants, such as polyoxyethylene polyoxypropylene alkyl ethers and polyoxyethylene alcohol ethers.

The polymerization conditions are usually appropriately determined depending on the monomer used and the copolymerization mol%, and the temperature is in the range of 0 to 100 ° C. In particular, when the water-in-oil emulsion polymerization method is applied, it is carried out in the range of 20 to 80 ° C, preferably 20 to 60 ° C. For the initiation of polymerization, a radical polymerization initiator is used. These initiators may be either oil-soluble or water-soluble, and can be polymerized by any of azo, peroxide, and redox systems. Examples of oil-soluble azo initiators are 2,2′-azobisisobutyronitrile, 1,1-azobiscyclohexanecarbonitrile, 2,2′-azobis-2-methylbutyronitrile, 2,2 Examples include '-azobis-2-methylpropionate, 4,4'-azobis- (4-methoxy-2,4-dimethyl) valeronitrile.

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

The polymerization concentration of the monomer is in the range of 20 to 50% by mass, and preferably in the range of 25 to 40% by mass. The concentration and temperature of the polymerization are appropriately determined depending on the composition of the monomer, the polymerization method, and the selection of the initiator. Set. The molecular weight of the water-soluble polymer obtained by polymerizing these monomers is in the range of 3 million to 30 million, preferably in the range of 3 million to 20 million.

Inorganic salts can be added in the water-in-oil emulsion. The timing of adding the salt is in an aqueous solution in which a monomer mixture comprising an ionic monomer, a nonionic monomer and a crosslinkable monomer is mixed, in a water-in-oil emulsion after copolymerization, or in oil. In water emulsion dilutions, etc.

As the inorganic salt to be added, a combination of a cation such as an alkali metal ion or ammonium ion such as sodium or potassium and an anion such as halide ion, sulfate ion, nitrate ion or phosphate ion can be used. is there. The concentration of these salts is 0.5% by mass to 15% by mass.

Next, the mixing means will be described. As the mixing means in the addition system used in the present invention, any mixing means may be used as long as the technical idea of the mixing used in the present invention can be achieved. Implementation is possible. For example, the following flow may be configured. For example, as an example of the apparatus, a part of the main papermaking raw material flow is used as a bypass flow, and the bypass flow is further divided into two, and one split flow is (1) a portion that forms a high flow rate / high-speed jet flow (injection) (Flow), (2) The other part of the diversion is to expand the part where the chemical stream is injected and to entangle the chemical stream into the jet stream (mixing flow). (3) To add the chemical, What consists of the part (chemical flow) which injects into a jet stream, rotating helically etc. can be used.

The three flows are configured by piping having a concentric cross section. A mixing flow is located in the middle of the concentric circles, an injection flow is located on the outermost side, and a chemical flow is located between the mixing flow and the injection flow, and each flow has a form of joining at the tip. The chemicals in the chemical flow are spread out by the mixing flow, come into contact with the injection flow, are quickly mixed therein and added to the main papermaking raw material stream.

In the part (injection flow) where a part of the main paper raw material flow is used as a bypass flow to form a large flow rate and high speed jet flow, a part of the main paper raw material flow is used as a bypass flow, and the bypass flow is further divided into two or more. One of the papermaking raw materials is pressurized by, for example, a booster pump to form a strong spiral jet stream that is accelerated to a flow rate 5 to 20 times that of the bypass stream. At this time, it is preferable to accelerate to a flow rate of 5 to 10 L / s.

In the part (chemical flow) which injects with respect to the said jet flow while spirally rotating a chemical | medical agent, it ejects in a film form, spirally rotating with respect to a jet stream from a nozzle part. Since the flow rate is slow and the share is minimized, the impact on the drug is minimal. It is preferable to inject the chemical at a flow rate of 0.1 to 1.0 L / s.

The other diversion flow (mixing flow) obtained by diverting the bypass flow plays a role of expanding the chemical flow and entraining the chemical in the jet flow, and is discharged in a spray form to expand the chemical flow and entrain it in the injection flow. The mixing flow rate is preferably 1 to 2 L / s. Specific examples of the apparatus described above include “Trump Jet” manufactured by Wet End Technology.

The feature of the chemical addition method in the present invention is added to the main papermaking raw material stream that has passed through the screen, which is the final shearing step. Since the polymer is not subjected to large shear by passing through the screen, the maximum effect is exhibited without the polymer being cut. Since the chemicals are widely and deeply dispersed in the main papermaking material flow pipes, they exhibit a very high mixing effect, so even if they have a high molecular weight, they do not disrupt the texture of the paper. Therefore, in the conventional addition method, a higher molecular weight yield improver that may cause collapse of the formation can be used. In the mixing means given in the above example, since it is added at a high speed to the main raw material flow, if the flow rate of the chemical is 0.1 L / s or more and the viscosity is 300 mPa · s or less, the fresh water for dilution is unnecessary. The flow rate and viscosity are preferred. If it does not fall within the range, it is diluted with fresh water, but the amount of fresh water used can be greatly reduced compared to the conventional addition method.

As explained in the background art, when the papermaking raw material is added before passing through the screen, the polymer is cut by the share of the screen, so in order to obtain a large yield improvement, the addition rate of the yield improver It is necessary to increase. On the other hand, with addition after passing through the screen, there is a risk that the formation will be lost due to the problem of mixing, and the addition rate must be suppressed to a minimum, and a significant increase in yield and productivity cannot be expected. Therefore, in the present invention, a yield improver comprising a high molecular weight acrylamide copolymer, preferably an oil which is a vinyl polymerized crosslinkable water-soluble cationic or amphoteric polymer having a charge encapsulation rate of 15% or more and 90% or less. The chemical is effectively mixed by the addition method using the mixing means of the water-in-water emulsion and the papermaking raw material stream, and a remarkable effect is exhibited because it is added after passing through the screen.

The papermaking system in the present invention can be applied not only to one kind of chemical addition but also to two or more kinds of chemical addition. That is, as described in claim 2, after the bypass flow is divided into three, the first chemical is a liquid flow of a cationic or amphoteric polymer such as a yield improver, and two of the three divided flows. One split stream is mixed by mixing means and refluxed to one point of the main papermaking raw material stream. As the second type, the flow of the anionic polymer, bentonite or colloidal silica and the remaining one split stream are the same as the other mixing means. There is also a method of mixing by the mixing means and refluxing to one place of the main papermaking raw material stream downstream from the place where the cationic or amphoteric polymer is added.

By applying the above formulation, it can be added simultaneously with filler, paper strength agent, sizing agent, sulfuric acid band and other papermaking chemicals using the same mixing means as the yield improver and / or paper quality improver, By another mixing means, it can be added at a location closer to the paper machine than a sizing agent fixing agent, a freeness improving agent, an anionic water-soluble polymer, bentonite or colloidal silica. Therefore, in the present invention, as a yield improver and / or paper quality improver, a water-in-oil emulsion which is a vinyl polymerization crosslinkable water-soluble cationic or amphoteric polymer having a charge inclusion rate of 15% or more and 90% or less is used. By using the addition method and mixing means used in the present invention, it is effectively mixed by adding to the papermaking raw material after passing through the screen, and exhibits a remarkable effect.

The water-in-oil emulsion which is a vinyl polymerized crosslinkable water-soluble cationic or amphoteric polymer having a charge encapsulation rate of 15% or more and 90% or less used in the present invention is a water-soluble polymer having a charge encapsulation rate of less than 15%. Compared to the above, the so-called cross-linking has progressed, and as a result of increasing the number of sites that bind to the surface of the pulp fiber and filler contained in the papermaking raw material, the dispersion and adsorption to the papermaking raw material is promoted and more effective. It is considered that a high yield effect can be obtained by synergy with mixing. If the charge encapsulation rate is higher than 90%, the crosslinking proceeds too much, which is disadvantageous because the addition amount increases and the addition cost increases.

It is also possible to install the mixing means in a white water piping system that is circulated in the main papermaking raw material stream after passing through the screen. That is, as described in claim 3, instead of the bypass flow of the papermaking raw material, the white water flow is divided into two or more, and then two of the divided flows and the yield improver and / or the paper quality are mixed by the mixing means. It is also possible to mix the improver stock solution or diluent and reflux it in one place of the main papermaking material stream. In this conceptual diagram, as shown in FIG. 1 , the chemical is added using the flow of white water shown in FIG. 1 instead of bypassing the main papermaking raw material flow. Alternatively, as described in claim 2 and conceptually illustrated in FIG. 2, after dividing the bypass of the main papermaking raw material flow into three, the two diversions and the yield improver and / or the paper quality improver are combined. Mixing means by mixing means, refluxing to the main papermaking raw material stream, and another branching flow and one or more selected from anionic water-soluble polymer, bentonite or colloidal silica are mixed in the same mixing means as the other mixing means And the mixture is refluxed to the main papermaking raw material stream at one location downstream of the location where the cationic or amphoteric polymer is added. The target paper is not particularly limited and can be applied to any paper. Newspaper, high-quality paper, PPC paper, coated base paper, and fine coating that require improved yield without impairing the texture. The effect is more exerted on paper and paperboard that requires the maximum effect with a minimum addition rate.

The following synthesis examples specifically illustrate the vinyl polymerized crosslinkable water-soluble cationic or amphoteric polymer of the present invention, but the present invention is not limited to the following synthesis examples.

(Synthesis Example 1)
A four-necked 500 ml separable flask equipped with a stirrer, reflux condenser, thermometer and nitrogen inlet tube, 127.5 g of isoparaffin having a boiling point of 190 ° C. to 230 ° C., 7.5 g of sorbitan monooleate and polyoxyethylene sorbitan monostearate 5 0.0 g was charged and dissolved. Separately, 58.1 g of 80% by mass acryloyloxyethyltrimethylammonium chloride (hereinafter abbreviated as DMQ), 307.0 g of 50% by mass acrylamide (abbreviated as AAM), 1.00 g of a 0.2% aqueous solution of methylenebisacrylamide, and 0.1% of isopropyl alcohol. 4 g (0.2 part by mass of monomer) was collected and added. The oil and the aqueous solution were mixed and emulsified with stirring at 1000 rpm for 2 minutes with a homogenizer. The monomer composition at this time is DMQ / AAM = 10/90 (mol%).

After maintaining the temperature of the obtained emulsion monomer solution at 45 ± 2 ° C. and performing nitrogen substitution for 30 minutes, 0.1 g of dimethyl-2,2′-azobis (methyl 2-methylpropionate) 0.05 mass%) was added to initiate the polymerization reaction. Polymerization was carried out at 45 ± 2 ° C. for 1.5 hours, and then the mixture was heated to 70 ° C. and kept for 1 hour to complete the reaction. After polymerization, 10.0 g of polyoxyethylene decyl ether (2.0% by mass with respect to the liquid) was added to and mixed with the resulting water-in-oil emulsion as a phase inversion agent. When the product viscosity was measured with a B-type viscometer, it was 320 mPa · s. The charge inclusion ratio obtained by the colloid titration method and the above formula is 24.6%, which is regarded as trial production-1. Further, by the same operation as in Synthesis Example 1, DMQ / AAM = 10/90 (mol%) charge inclusion rate 45.8% (prototype-2), DMQ / AAM = 20/80 (mol%) charge inclusion rate 39.2 % (Prototype-3), DMQ / AAM = 20/80 (mol%) charge inclusion rate 75.3% (prototype-4), DMQ / DMC / AAC / AAM = 10/10/5/75 (mol%) Charge inclusion rate 41.0% (prototype-5), DMQ / DMC / AAC / AAM = 10/10/5/75 (mol%) charge inclusion rate 55.5% (prototype-6),
DMQ / AAM = 5/95 (mol%) charge inclusion rate 60.7% (prototype-7), DMQ / AAM = 35/65 (mol%) charge inclusion rate 45.0% (prototype-8) Water-soluble polymer was synthesized. The results are shown in Table 1.

(Synthesis Example 2)
For Prototype-2, Prototype-4, and Prototype-6, 7% by mass of ammonium sulfate was added to the crosslinkable water-soluble polymer in the water-in-oil emulsion, and these were prepared as Prototype-9 and Prototype-10, respectively. And prototype-11. The results are shown in Table 1.

(Comparative Synthesis Example 1)
A four-necked 500 ml separable flask equipped with a stirrer, reflux condenser, thermometer and nitrogen inlet tube, 127.5 g of isoparaffin having a boiling point of 190 ° C. to 230 ° C., 7.5 g of sorbitan monooleate and polyoxyethylene sorbitan monostearate 5 0.0 g was charged and dissolved. Separately, 58.1 g of 80% by mass acryloyloxyethyltrimethylammonium chloride (hereinafter abbreviated as DMQ), 307.0 g of 50% by mass acrylamide (abbreviated as AAM), 0.20 g of a 0.2% aqueous solution of methylenebisacrylamide, and 0.1% of isopropyl alcohol. 4 g (0.2 part by mass of monomer) was collected and added. The oil and the aqueous solution were mixed and emulsified with stirring at 1000 rpm for 2 minutes with a homogenizer. The monomer composition at this time is DMQ / AAM = 10/90 (mol%).

The obtained emulsion was maintained at a temperature of the monomer solution at 40 to 43 ° C. and purged with nitrogen for 30 minutes, and then dimethyl-2,2-azobisisobutyrate (V-601, manufactured by Wako Pure Chemical Industries) 7 g (0.038% by mass with respect to the monomer) was added to initiate the polymerization reaction. The reaction was completed by polymerization at 42 ± 2 ° C. for 12 hours. After the polymerization, 5.0 g of polyoxyethylene polyoxypropylene alkyl ether (1% by mass with respect to the liquid) was added and mixed as a phase inversion agent to the resulting water-in-oil emulsion. Then, when the product viscosity was measured with a B-type viscometer, it was 450 mPa · s. When the charge inclusion rate is determined by the above calculation formula, it is 13.8%, and is set as trial production-12. Further, a crosslinkable water-soluble polymer having DMQ / AAM = 20/80 (mol%) and a charge inclusion rate of 95.8% was synthesized by the same operation as in Comparative Synthesis Example 1 (prototype-13). The results are shown in Table 1.

(Comparative Synthesis Example 2)
For Trial-12 and Trial-13, ammonium sulfate was added at 7% by mass to the water-soluble polymer in the water-in-oil emulsion, and these were designated as Trial-14 and Trial-15, respectively. The results are shown in Table 1.

(Table 1)
DMQ: acryloyloxyethyltrimethylammonium chloride DMC: methacryloyloxyethyltrimethylammonium chloride, AAC: acrylic acid, AAM: acrylamide, crosslinkable monomer addition amount: to monomer ppm (mass ratio), ammonium sulfate: to Water-soluble polymer mass%

Yield rate measurement test was performed with a Brit dynamic jar tester. Use 200 mesh wire. The raw material used was a newspaper papermaking raw material having a solid content concentration of 1.2% by mass and a light calcium calcium carbonate or other Ash content of 32.4% to the solid content concentration. The physical properties of the papermaking raw materials are pH 7.3, Whatman No. The required cation amount of 41 filter paper filtrate using the Mutec PCD-03 type is 0.006 meq / L. After stirring for 20 seconds at a stirring speed of 1500 rpm, 150 ppm of Samples 1 to 11 of the synthesis example is added to the solid content of the paper, and it is added after passing through the screen for 10 seconds at a stirring speed of 1500 rpm. After stirring, the filtrate was collected and ADVANTEC, no. After filtration with two filter papers, SS was measured, and the total yield was measured. Then, the filter paper was ashed at 525 ° C. for 2 hours, and the ash yield was measured. The results are shown in Table 2.

(Comparative Example 1)
Using the same papermaking raw material as in Example 1, 200 ppm of the synthesis examples of prototyping-1 to prototyping-4 and prototyping-9 to prototyping-10 are added to the solids for the paper stock, and added in front of the screen. Assuming that the mixture was stirred at 1500 rpm for 30 seconds, the filtrate was collected and ADVANTEC, No. After filtration with two filter papers, SS was measured, and the total yield was measured. Then, the filter paper was ashed at 525 ° C. for 2 hours, and the ash yield was measured. The results are shown in Table 2.

(Comparative Example 2)
Using the same papermaking raw materials as in Example 1, 150 ppm of Comparative Synthesis Examples, Trial-12 to Trial-15, was added to the solids for the paper stock, and added after passing through the screen at a stirring speed of 1500 rpm. After stirring for 10 seconds, the filtrate was collected and ADVANTEC, no. After filtration with two filter papers, SS was measured, and the total yield was measured. Then, the filter paper was ashed at 525 ° C. for 2 hours, and the ash yield was measured. The results are shown in Table 2.

(Table 2)

When it is assumed that Trial-1 to Trial-11 of Example 1 are added after passing through the screen, they are added before Trial-1 to Trial-4 and Trial-9 to Trial-10 in Comparative Example 1. As a result, a higher yield effect was exhibited even at a lower addition rate than when it was added. In addition, the trial production-9 to the trial production-11 to which the inorganic salts are added has an improved effect compared with the trial production -1 to the trial production-8 to which the inorganic salts are not added. It is presumed that the inorganic salt was added and the viscosity of the solution was lowered, and as a result, the agglomeration effect was increased and the yield was improved. Moreover, the effect of Example 1 was not acquired by addition of trial production-12-trial production-15 which assumed adding after passing the screen of the comparative example 2. FIG. This is presumed to be due to the fact that the charge inclusion rates of trial production-12 and trial production-13 are out of the scope of the present invention, so that the dispersion / adsorption to the papermaking raw material is poor. In order to improve the yield, it was confirmed that adding the prototype polymer of the synthesis example after passing through the screen increases the dispersion and adsorption to the papermaking raw material, and further reduces the share and has the maximum effect.

Newspaper machine with papermaking speed of 1250m / min, basis weight of 43g / m ² , 200ppm water-in-oil emulsion polymer with weight average molecular weight of 15 million and charge inclusion rate of 13.6% before passing through screen Although the solid content was added, “Trump Jet” of Wet End Technology Co., Ltd. having a form in which the mixing means described in the present invention was embodied in the water-soluble polymer of Synthesis Example 1 and Trial Production-3 of the present invention. It was installed at a location located after passing through the screen, and 100 ppm (mass ratio) to the solid content of the paper was added. Before changing the addition method, the total wire yield was 45% and the ash yield was 25% when the current water-in-oil emulsion polymer was used. On the other hand, after the addition method was changed, the water-soluble polymer of Synthesis Example 1 and Trial Production-3 was improved to a wire yield rate of 48% and an ash yield rate of 30% by using the addition method used in the present invention. did. It is considered that the water-soluble polymer of Synthesis Example 1 and Trial Production-3 was dispersed and adsorbed with respect to the papermaking raw material and mixed efficiently, and the maximum effect was exhibited. In addition, the texture was almost the same as when the current water-in-oil emulsion polymer was added and in the synthesis example, trial production-3, and no degradation of the texture was observed.

In the papermaking method described in Claim 1 , it is a system figure for adding the vinyl polymerization type crosslinking | crosslinked water-soluble cationic or amphoteric polymer used by this invention. In the papermaking method described in Claim 2, it is a system diagram for adding a vinyl polymerization type crosslinkable water-soluble cationic or amphoteric polymer used in the present invention.

1 White water circulated in the main papermaking raw material stream 2 Last screen 3 Papermaking chemical storage tank (yield improver and / or paper quality improver)
4 Papermaking chemical flow 5 Bypass flow 6 One of the divided flows further divided by the bypass flow 7 One of the divided flows further divided by the bypass flow 8 Mixing means 9 Flow of the papermaking raw material to the paper machine 10 Main paper raw material flow 11 Papermaking chemical storage tank 1 (yield improver and / or paper quality improver)
12 Paper manufacturing chemical storage tank 2 (anionic water-soluble polymer, bentonite, colloidal silica, etc.)
13 Last screen 14 Main paper raw material flow 15 Paper manufacturing chemical flow 1
16 Bypass flow 17 One of the divided flows further divided by the bypass flow 18 One of the divided flows further divided by the bypass flow 19 Mixing means 1
20 Papermaking chemical flow 2
21 One of the diverted flows further dividing the bypass flow 22 Mixing means 2
23 Flow of papermaking raw material to paper machine

Claims (6)

In the papermaking raw material before papermaking, a part of the main papermaking raw material flow that passed through the last screen is made into a bypass flow, the bypass flow is further divided into two, and then one or more papermaking chemicals and the two divided flows are mixed. Mixed by means,
Then, by refluxing to one place of the main papermaking raw material flow, after adding and mixing the papermaking chemical, a papermaking method for papermaking,
One of the papermaking chemicals is a yield improver and / or a paper quality improver, the monomer represented by the following general formula (2) and / or (3), 3 to 35 mol%, the following general formula (1) A monomer mixture aqueous solution consisting of 0 to 50 mol% of a monomer represented by formula (1)), 15 to 97 mol% of a copolymerizable nonionic water-soluble monomer, and a crosslinkable monomer is added with a surfactant. The charge inclusion ratio is 15% or more and 90% or less, which is produced by emulsifying and polymerizing an immiscible organic liquid in water to form a continuous phase and a monomer mixture aqueous solution to be a dispersed phase, and then adding a phase inversion agent as appropriate. A paper-making method, which is a water-in-oil emulsion comprising a vinyl-polymerizable cross-linkable water-soluble cationic or amphoteric polymer having a weight average molecular weight in the range of 10 million to 30 million .
General formula (2)
R ₁ is hydrogen or a methyl group, R ₂ and R ₃ are alkyl groups having 1 to ₃ carbon atoms, alkoxy groups, and R ₄ is hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkoxy group, or a benzyl group. Different types may be used. A represents oxygen or NH, B represents an alkylene group or alkoxylene group having 2 to 4 carbon atoms, and X ₁ represents an anion.
General formula (3)
R ₅ represents hydrogen or a methyl group, R ₆ and R ₇ each represent an alkyl group having 1 to 3 carbon atoms, an alkoxy group or a benzyl group, and X ₂ represents an anion.
General formula (1)
R ₈ 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 ₉ Represents hydrogen or COO ^— Y ₂ ⁺ , Y ₁ or Y ₂ represents hydrogen or a cation, respectively. In the papermaking raw material before papermaking, a part of the main papermaking raw material flow that passed through the last screen is a bypass flow, and the bypass flow is further divided into three,
Two of the three divided streams and one or more papermaking chemicals are mixed by a mixing means, refluxed to one place of the main papermaking raw material stream, the remaining one divided stream and an inorganic or organic anionic property The substance solution stream or the dispersion liquid stream is mixed by the same mixing means as the other mixing means, and is added and mixed by refluxing to one place of the main papermaking raw material stream downstream from the addition position of the papermaking chemical. Then, a papermaking method for making paper, wherein one of the papermaking chemicals is a yield improver and / or a paper quality improver, and is a monomer represented by the following general formula (2) and / or (3) From 3 to 35 mol%, from 0 to 50 mol% of a monomer represented by the following general formula (1), 15 to 97 mol% of a copolymerizable nonionic water-soluble monomer, and a crosslinkable monomer Unmixed aqueous monomer mixture with water using a surfactant After emulsifying and polymerizing the solvable organic liquid as a continuous phase and the monomer mixture aqueous solution as a dispersed phase, the charge inclusion ratio is 15% or more and 90% or less produced by adding a phase inversion agent as appropriate. A paper-making method, which is a water-in-oil emulsion comprising a vinyl polymerization crosslinkable water-soluble cationic or amphoteric polymer having a molecular weight in the range of 10 to 30 million .
General formula (2)
R ₁ is hydrogen or a methyl group, R ₂ and R ₃ are alkyl groups having 1 to ₃ carbon atoms, alkoxy groups, and R ₄ is hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkoxy group, or a benzyl group. Different types may be used. A represents oxygen or NH, B represents an alkylene group or alkoxylene group having 2 to 4 carbon atoms, and X ₁ represents an anion.
General formula (3)
R ₅ represents hydrogen or a methyl group, R ₆ and R ₇ each represent an alkyl group having 1 to 3 carbon atoms, an alkoxy group or a benzyl group, and X ₂ represents an anion.
General formula (1)
R ₈ 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 ₉ Represents hydrogen or COO ^— Y ₂ ⁺ , Y ₁ or Y ₂ represents hydrogen or a cation, respectively. The papermaking method according to claim 1 or 2, wherein white water circulated in the main papermaking raw material stream is used as a bypass flow instead of the main papermaking raw material bypass flow. The inorganic or organic anionic substance is at least one selected from colloidal silica, bentonite, and a copolymer of a monomer represented by the following general formula (1) and (meth) acrylamide. The paper making method according to claim 2, wherein the paper making method is characterized.
General formula (1)
R ₈ 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 ₉ represent respectively + _Y ^2, _{Y 1} or _{Y 2} is hydrogen or a cation and - is hydrogen or ^COO. The papermaking method according to claim 1 or 2 , wherein the vinyl polymer-based cross-linkable water-soluble cationic or amphoteric polymer has a charge inclusion rate in the range of 35 to 90%. The papermaking method according to claim 1 or 2 , wherein the water-in-oil emulsion contains an inorganic salt.