JP2011111698A - Papermaking method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a papermaking method for producing paper and paperboard and having improved yield and productivity. <P>SOLUTION: A part of a main papermaking stock flow passed through a final screen before papermaking process is used as a bypass flow, the bypass flow is divided into two flows, one or more papermaking chemicals are mixed with these two divided flows by a mixing means, the mixture is returned to a point of the main papermaking stock flow to add and mix the papermaking chemicals, and the papermaking stock is subjected to papermaking process, wherein the papermaking chemicals suitable for the papermaking process is a water-in-oil polymer emulsion containing a polymer having hydrophilic and hydrophobic structure units and produced by emulsifying a water-phase containing a water-soluble vinyl monomer and an oil phase comprising a hydrocarbon solvent with an emulsifier and polymerizing the emulsion. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a papermaking method capable of improving yield and improving productivity in a paper and paperboard manufacturing process.

2. Description of the Related Art Conventionally, in a papermaking process such as coated base paper, PPC paper, high-quality paper, paperboard, and newsprint, various yielding systems have been used in order to improve the yield rate of fine fibers, fillers, and the like. As a commonly used retention agent system, there is a prescription in which an acrylamide-based water-soluble polymer is added before and after a fan pump or screen which is a papermaking shearing process.

In order to maintain and improve the yield rate in response to changes in papermaking conditions such as the recent increase in fine fiber content in papermaking raw materials and the increase in the use ratio of fine calcium carbonate as a filler, for example, neutral newspaper printing In the manufacture of paper, a method has been proposed in which an emulsion type cationic polyacrylamide material having a weight average molecular weight of 15 million or more by an intrinsic viscosity method is added to a paper stock as an additive. (Patent Document 1)

In general, as a method for obtaining a high molecular weight polyacrylamide-based substance, a method of obtaining a water-in-oil emulsion is effective. However, when a polymer is dissolved in a solvent, the higher the molecular weight, the higher the concentration, It is known that the rate of dissolution that diffuses uniformly into the solvent due to its own relaxation is slow. Therefore, the method of adding a stock solution of emulsion-type polyacrylamide-based substance or a high-concentration aqueous solution, or the method of adding it in a process close to the wire part of a paper machine is highly likely to lead to incomplete dissolution or trouble during papermaking. .

Emulsion-type polyacrylamide substances are stabilized as water-in-oil emulsions with low HLB emulsifiers, and when dissolved in dilution water, it is necessary to stabilize them as phase-inverted oil-in-water emulsions. There is. For this reason, it takes a lot of time, labor, and equipment, such as a method of diluting to a low concentration by taking sufficient time to diffuse uniformly, or a method of once diluting with a dilution water after dissolving at a high concentration. . (Patent Document 2)

On the other hand, specific equipment for the purpose of efficient and uniform mixing of additives to paper pulp, mutual rapid mixing, fixing of additives to paper pulp, investment, reduction of equipment and operation costs, reduction of chemical costs, etc. A method has been proposed in which the additive is fed to a paper pulp suspension stream fed to a paper machine. (Patent Document 3) This method is effective for improving the yield and productivity, and it is most effective to add a polymer after the screen, which is the final shearing step of the papermaking process.

However, in order to improve yield and productivity, it is difficult to add high-molecular weight emulsion type polyacrylamide substances as additives using this method. For this reason, it has not been realized due to inferior dispersibility of the polymer at the time of addition and a great amount of time and equipment required for improving dispersibility.
JP 2006-16716 A JP 2008-208494 A Special table 2008-506859 gazette

An object of the present invention is to provide a papermaking method for improving yield and improving productivity in a paper and board making process.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have determined that a part of the main papermaking raw material flow that has passed through the last screen in the papermaking raw material before papermaking is a bypass flow, and the bypass flow is further increased. After being split into two, one or more papermaking chemicals and the two split streams are mixed by a mixing means, and then refluxed to one place of the main papermaking raw material stream to add and mix the papermaking chemicals to make paper. In the papermaking method, the papermaking agent has hydrophilic and hydrophobic structural units obtained by emulsifying an aqueous phase containing a vinyl-based water-soluble monomer and an oil phase composed of a hydrocarbon solvent with an emulsifier and then polymerizing. It was discovered that by making a paper and paperboard using a water-in-oil polymer emulsion containing a polymer, it is possible to significantly improve yield and productivity. Led was.

A feature of the present invention is that a part of the papermaking raw material flow after the final shearing process before paper making, that is, after passing through the last screen, is used as a bypass flow, and this bypass flow and the drug or drug dilution liquid flow are mixed to change the flow of the mixture. This is because a highly compatible chemical has been discovered in an addition method that allows the papermaking raw material and the chemicals to be mixed efficiently by returning to the main paper raw material flow again.

Conventionally, the chemical is added to the main paper stock stream after increasing the flow rate of the primary solution of the chemical with secondary dilution water and lowering the chemical viscosity. 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 chemical addition method used in the present invention, in order to improve these disadvantages, after the papermaking raw material passes through the final shearing step, a part of the papermaking raw material flow is used as a bypass flow, and this bypass flow and secondary dilution water are used. Mix with unused papermaking chemical solution.

However, since the secondary dilution water is not used, the viscosity of the chemical is increased, the time to reach the wire part is short, and there is a risk that the drug cannot be distributed uniformly, or homogenization by shearing because it is added after the final shearing process Problems such as cannot be expected.

Contains a polymer having hydrophilic and hydrophobic structural units obtained by emulsifying an oil phase composed of an aqueous phase containing a vinyl-based water-soluble monomer and a hydrocarbon solvent used in the present invention with an emulsifier and then polymerizing. A water-in-oil polymer emulsion solves these problems. By improving the dispersibility of chemicals that were previously poorly dispersible in papermaking raw materials with a small amount of high viscosity, By improving the dispersibility, the yield rate is remarkably improved, and the productivity can be improved by avoiding papermaking troubles.

In the water-in-oil polymer emulsion of the present invention, an aqueous phase containing a water-soluble polymer having a vinyl-based water-soluble monomer structural unit is a dispersed phase, and an oil phase composed of a hydrocarbon solvent is a continuous phase. It contains a polymer having hydrophilic and hydrophobic structural units. In addition to the polymer having hydrophilic and hydrophobic structural units, the above-mentioned ordinary surfactant may be used in combination. As the order of emulsification, a polymer having hydrophilic and hydrophobic structural units and a normal surfactant may be added simultaneously to emulsify and polymerize, or after emulsification with a normal surfactant, hydrophilic and hydrophobic Various methods such as addition of a polymer having a structural unit and polymerization, or polymerization after emulsification with a normal surfactant, followed by addition of a polymer having hydrophilic and hydrophobic structural units There is.

As the vinyl water-soluble monomer, any of a cationic monomer, an anionic monomer and / or a nonionic monomer can be used.

Examples of the cationic monomer include dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylamide, and methyl diallylamine. The tertiary amino group-containing monomer is quaternary by methyl chloride or benzyl chloride. (Meth) acryloyloxyethyltrimethylammonium chloride, (meth) acryloyloxy 2-hydroxypropyltrimethylammonium chloride, (meth) acryloylaminopropyltrimethylammonium chloride, (meth) acryloyloxyethyldimethylbenzylammonium chloride , (Meth) acryloyloxy 2-hydroxypropyldimethylbenzylammonium chloride, (meth) acryloylaminopropyldimethylbenzylammonium chloride, dimethyldiallylammo Um chloride can be exemplified.

Examples of the anionic monomer 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. .

Nonionic monomers include (meth) acrylamide, N, N-dimethylacrylamide, vinyl acetate, acrylonitrile, methyl acrylate, 2-hydroxyethyl (meth) acrylate, diacetone acrylamide, N-vinyl pyrrolidone, N -Vinylformamide, N-vinylacetamide and the like can be exemplified.

These vinyl water-soluble monomers can be copolymerized with one kind or two or more kinds.

The aqueous phase containing the aqueous monomer solution can contain a compound having chain transferability in addition to the monomer. Examples of compounds having chain transferability include 2-ppanol, 2-mercaptoethanol, sodium methallyl sulfonate, sodium formate and the like, which are appropriately added depending on the composition, polymerization rate and molecular weight of the target polymer. To do.

The oil phase composed of a hydrocarbon-based solvent that forms a continuous phase is not particularly limited as long as it can be emulsified with a surfactant by causing phase separation when mixed with water, but paraffins, kerosene, light oil, medium oil, etc. Examples thereof include mineral oils, hydrocarbon-based synthetic oils having characteristics such as boiling point and viscosity in substantially the same range as these, and mixtures thereof. The content is preferably in the range of 20 wt% to 50 wt% with respect to the total weight of the water-in-oil emulsion.

Examples of surfactants effective for emulsifying these water and oil phases to form water-in-oil emulsions include sorbitan monooleate, sorbitan dioleate, sorbitan trioleate, sorbitan monostearate. Sorbitan distearate, sorbitan monolaurate, sorbitan dilaurate, sorbitan monopalmitate, sorbitan dipalmitate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan trioleate, poly Examples include oxyethylene sorbitan monostearate, polyoxyethylene stearyl ether, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene tridecyl ether, polyoxyethylene oleyl ether, In addition to the polymer nonionic field It may be used active agents.

The surfactant HLB used as the surfactant is preferably in the range of 1 to less than 9, considering the stability of the emulsion and the water-in-oil polymer emulsion.

In addition to the surfactant used as the emulsifier and the polymer having hydrophilic and hydrophobic structural units, a surfactant having an HLB of 9 or more and less than 20 can affect the stability of the emulsion and the water-in-oil polymer emulsion. It is preferable to use in a range not given. By using this, the speed of primary dissolution of water-in-oil polymer emulsion in water and uniform dispersion in papermaking raw materials are promoted.

In the present invention, it is essential to contain a polymer having hydrophilic and hydrophobic structural units in addition to the emulsifier. The polymer having hydrophilic and hydrophobic structural units can be added either before or after the polymerization reaction. A method of adjusting the ratio of hydrophilic structural units and hydrophobic structural units effective for forming a water-in-oil emulsion and adding them before polymerization and using them as emulsifiers is preferred.

The polymer having hydrophilic and hydrophobic structural units in the present invention can be obtained by copolymerizing a monomer mixture containing a monomer having a hydrophilic structure and a monomer having a hydrophobic structural unit. it can.

Examples of the monomer having a hydrophilic structure include polyethylene glycol (meth) acrylate, polyethylene glycol (meth) acrylamide, polyethylene glycol polypropylene glycol (meth) acrylate, polyethylene glycol polypropylene glycol (meth) acrylamide, and methoxides and phenoxides thereof. it can. In particular, it preferably has an oxyethylene structure, and more preferably methoxy or phenoxypolyethylene glycol (n = 3 to 23) (meth) acrylate.

The monomer having a hydrophobic structure must be copolymerizable with a monomer having an alkyl group and having the hydrophilic structure. The number of carbon atoms forming the alkyl group is preferably in the range of 4 to 18, more preferably an ester of a higher alcohol having 4 to 18 carbon atoms and (meth) acrylic acid.

A polymer having hydrophilic and hydrophobic structural units is obtained by copolymerizing a mixture containing the monomer with a hydrocarbon solvent of the same type as the hydrocarbon solvent forming the water-in-oil polymer emulsion. It is possible to obtain other monomers that can be obtained and copolymerized in this solvent.

Examples of the monomer that can be copolymerized with the monomer having a hydrophilic structure and the monomer having a hydrophobic structure in the hydrocarbon solvent of the present invention include (meth) acrylamide and (meth) dimethyl. Acrylamide, (meth) acrylonitrile, (α-methyl-) styrene, vinyl acetate, vinylpyrrolidone, (meth) acrylic acid, itaconic acid, maleic anhydride, maleic acid, dimethylaminoethyl (meth) acrylate, (meth) acrylic Examples include diethylaminoethyl acid, (meth) acryloyloxy 2-hydroxypropyldimethylamine, dimethylaminopropyl (meth) acrylamide, and diethylaminopropyl (meth) acrylamide, and one or more of these can be used in combination. Dimethylaminoethyl (meth) acrylate, (meth) a Tertiary amine vinyl monomer and / or carboxylic acid vinyl monomer such as diethylaminoethyl rilate, (meth) acryloyloxy 2-hydroxypropyldimethylamine, dimethylaminopropyl (meth) acrylamide, diethylaminopropyl (meth) acrylamide The monomer is particularly preferably a dialkylaminoalkyl (meth) acrylate and / or (meth) acrylic acid monomer.

The polymer having hydrophilic and hydrophobic structural units is preferably 5 to 30 mol% of a monomer containing a hydrophilic structure, preferably 50 to 95 mol% of a monomer containing a hydrophobic structural unit, and the hydrophilic structure A copolymer obtained by copolymerizing a monomer mixture comprising a monomer containing a hydrophobic structure and a monomer containing a hydrophobic structure and a monomer copolymerizable in the range of 0 to 45 mol% in the hydrocarbon solvent is preferred.

As the composition range of the monomer containing the hydrophilic structure and the monomer containing the hydrophobic structure and the monomer copolymerizable in the hydrocarbon solvent, a tertiary amine vinyl monomer 0 to The ranges of 15 mol% and / or 0-15 mol% of carboxylic acid vinyl monomers are preferable.

The weight average molecular weight of the polymer having hydrophilic and hydrophobic structural units is not particularly limited as long as it is in the range of 1,000 to 2,000,000, but may be in the range of 3,000 to 50,000. preferable. If the molecular weight is too low, the performance as an emulsifier is low and the separation stability of the emulsion is poor, so that it is not practical. If the molecular weight is high, the hydrocarbon solvent solution has a high viscosity and is difficult to handle. The molecular weight can be adjusted by polymerizing a compound having chain mobility in a hydrocarbon solvent. The compound having chain transfer property is not particularly limited as long as it can coexist in a hydrocarbon solvent, and examples thereof include thiols and thioester compounds such as n-dodecyl mercaptan and 2-mercaptoethanol.

The addition amount of these surfactants is 0.5 to 10% by weight, preferably 1 to 5% by weight, based on the total amount of the water-in-oil emulsion.

The water-in-oil type polymer emulsion placed in the present invention is obtained by mechanically emulsifying these mixtures, adding a radical polymerization initiator to the obtained emulsion, and polymerizing with stirring.

Although the temperature at the time of superposition | polymerization changes with kinds of radical polymerization initiator, it is 5-55 degreeC generally. 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. Preferred are peroxide initiators such as azo initiators, t-butyl peroxide and benzoic peroxide, or redox polymerization initiators combining these with reducing agents such as sodium bisulfite and trimethylamine. The initiator is added in an amount of 50 to 5000 ppm, preferably 100 to 500 ppm per monomer at the start of polymerization.

The polymer obtained by removing the solvent preferably has an intrinsic viscosity of 10 to 35, particularly preferably 15 to 30 (dL / g) under the condition of a 1 N aqueous sodium chloride solution at 25 ° C.

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. That is, a part of the main papermaking raw material stream is used as a bypass flow. For example, as an example of the apparatus, the bypass flow is further divided into two, and one of these divided flows is (1) a large flow rate and a high-speed jet flow. Part to be formed (injection flow), (2) In order to add chemicals, the chemical flow is injected into the jet stream while rotating spirally (chemical flow), (3) The other split flow is injected with the chemical flow For example, it is possible to use a part composed of a part (mixing flow) that expands the part to be entrained and entangles the chemical flow into the jet flow.

The three flows are configured by piping having a concentric cross section. The mixing flow is located in the middle of the concentric circle, the injection flow is located on the outermost side, and the chemical flow is located between the mixing flow and the injection flow. Each flow has a shape that merges at the tip. The chemical flow chemicals contact the injection flow and are quickly mixed therein and added to the main paper stock 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 diverted flow that splits the bypass flow plays a role of expanding the chemical flow and entraining the chemical in the jet flow (mixing flow), and is discharged in the form of a spray to expand the chemical flow and be entrained in the jet 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.

In general, when the papermaking raw material is added before passing through the screen, the polymer is cut by the share of the screen. Therefore, in order to obtain a large yield improvement, it is necessary to increase the addition rate of the yield improver. 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. Accordingly, in the present invention, a yield improver comprising a high molecular weight acrylamide copolymer, that is, a means for mixing a water-in-oil polymer emulsion containing a polymer having a hydrophilic and hydrophobic structure and a papermaking raw material stream is provided. The chemicals are effectively mixed by the addition method used, and a remarkable effect is exhibited because the chemicals are 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, a liquid flow of a cationic polymer such as a yield improver to the first chemical and two of the three divided flows. The split stream is mixed by the mixing means and refluxed to one place of the main papermaking raw material stream, and as the second type, the remaining one split stream is mixed by another similar mixing means with the anionic polymer, bentonite or colloidal silica. There is also a method of refluxing to one location of the main papermaking raw material stream downstream from the location where the cationic polymer is added.

By applying the above formula, it can be added at the same time as filler, paper strength agent, sizing agent, sulfuric acid band and other papermaking chemicals by using the same mixing method as yield improvement / paper quality improvement agent. Depending on the means, a sizing agent, a freeness improver, an anionic water-soluble polymer, bentonite or colloidal silica can be added at a location closer to the paper machine. Accordingly, in the present invention, as a yield improving / paper quality improving agent, a water-in-oil polymer emulsion containing a polymer having a hydrophilic and hydrophobic structure is added using the addition method and mixing means used in the present invention. By being added to the papermaking raw material after passing through the screen, it is effectively mixed and exhibits a remarkable effect.

The water-in-oil polymer emulsion containing a polymer having a hydrophilic and hydrophobic structure used in the present invention is considered to be present in the same manner as an emulsifier at the interface between an aqueous phase and an oil phase. Since the chains and hydrophobic side chains are very bulky, it is presumed that the stability of the emulsion formed is low. For example, when a water-in-oil polymer emulsion is dispersed in water, phase inversion is carried out at a higher speed than in a water-in-oil polymer emulsion that does not contain a polymer having hydrophilic and hydrophobic structures, and the polymer rapidly An aqueous solution is formed.

The high dispersion speed in water means that the dispersion speed in the aqueous pulp slurry dispersion is high, the reaction speed of the water-soluble polymer with the pulp is high, and the machine is added as a place for addition after the passage of the screen. Even if added at a closer location, the risk of trouble due to non-uniform dispersion is low.

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 paper quality improver stock solution or diluent are mixed by the mixing means. Can be mixed and refluxed in one place of the main papermaking raw 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 diverting the main paper feed stream bypass into three, the two split streams and the yield improver are mixed by a mixing means, Reflux to the main papermaking raw material stream, mix another branch with one or more selected from anionic water-soluble polymer, bentonite or colloidal silica by another similar mixing means and return to the main papermaking raw material stream Let 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 acrylamide copolymer of the present invention will be specifically described by the following synthesis examples, but the present invention is not limited to the following synthesis examples.

(Polymer production example 1 having hydrophilic and hydrophobic structural units)
A 4-neck 500 mL separable flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet tube was charged with 60.01 g of methoxypolyethylene glycol acrylate (n = 9), 9.77 g of dimethylaminoethyl methacrylate, acrylic acid 2 -80.22 g of ethylhexyl, 149.55 g of alicyclic saturated hydrocarbon (initial boiling point 242 ° C., end point 82.8 ° C., aniline point 82.8 ° C.) and 0.45 g of 2-mercaptoethanol are charged, Nitrogen was introduced from the nitrogen introduction tube while stirring, and dissolved oxygen was removed for 30 minutes. After the internal temperature was set to 20 ° C. using a constant temperature water bath, 3.00 g of 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile) was added to initiate polymerization. The polymerization was completed after 24 hours had elapsed from the start of the temperature increase. The obtained polymer solution was designated as polymer emulsifier 1, and the composition and weight average molecular weight are shown in Table 1.

(Polymer production example 2 having hydrophilic and hydrophobic structural units)
The raw materials charged in the separable flask were 62.94 g of methoxypolyethylene glycol acrylate (n = 9), 10.25 g of dimethylaminoethyl methacrylate, 72.12 g of 2-ethylhexyl acrylate, and 4.70 g of acrylic acid. Hydrophilic and hydrophobic except that alicyclic saturated hydrocarbon (initial boiling point 242 ° C, end point 82.8 ° C, aniline point 82.8 ° C) was 149.55 g and 2-mercaptoethanol was 0.45 g. Polymerization was carried out in the same manner as in Polymer Production Example 1 having an ionic structural unit. The obtained polymer solution was designated as polymer emulsifier 2, and the composition and weight average molecular weight are shown in Table 1.

(Polymer production example 3 having hydrophilic and hydrophobic structural units)
The raw materials charged in the separable flask were 63.47 g of methoxypolyethylene glycol acrylate (n = 9), 10.33 g of dimethylaminoethyl methacrylate, 72.72 g of 2-ethylhexyl acrylate, 3.49 g of acrylonitrile, Hydrophilic and hydrophobic except that alicyclic saturated hydrocarbon (initial boiling point 242 ° C., end point 82.8 ° C., aniline point 82.8 ° C.) is 149.55 g and 2-mercaptoethanol is 0.45 g. Polymerization was carried out in the same manner as in Polymer Production Example 1 having a structural unit. The obtained polymer solution was designated as polymer emulsifier 3, and the composition and weight average molecular weight are shown in Table 1.

(Comparative Production Example 1 of polymer having hydrophilic and hydrophobic structural units)
The raw materials charged in the separable flask were 135.05 g of methoxypolyethylene glycol acrylate (n = 9), 12.62 g of dimethylaminoethyl methacrylate, 7.20 g of acrylic acid, and 0.45 g of 2-mercaptoethanol. Except for the above, polymerization was performed in the same manner as in Polymer Production Example 1 having hydrophilic and hydrophobic structural units.

(Comparative Production Example 2 of Polymer Having Hydrophilic and Hydrophobic Structural Units)
The raw materials charged in the separable flask were hydrophilic, except that 142.26 g of methoxypolyethylene glycol acrylate (n = 9), 7.74 g of dimethylaminoethyl methacrylate, and 0.45 g of 2-mercaptoethanol were used. Polymerization was carried out in the same manner as in Production Example 1 having a hydrophobic structural unit.

Polymerization was carried out in the same manner as in Production Example 2 of polymer having hydrophilic and hydrophobic structural units, except that 0.15 g of 2-mercaptoethanol was used. The obtained polymer solution was used as comparative polymer emulsifier 2, and the composition and weight average molecular weight are shown in Table 1.

(Production Example 1 of water-in-oil polymer emulsion)
A 500 mL beaker was charged with 237.9 g of a 50 wt% acrylamide aqueous solution, 101.3 g of an 80 wt% acryloyloxyethyltrimethylammonium chloride aqueous solution, 0.4 g of isopropyl alcohol, and 15.4 g of purified water, and then as an oil phase. Sorbitan monooleate 5.0 g, polyoxyethylene oleyl ether (n = 2) 5.0 g, alicyclic saturated hydrocarbon (initial boiling point 242 ° C., end point 82.8 ° C., aniline point 82.8 ° C.) 130.0 g And the mixture which mixed the polymer emulsifier 1 of manufacture example 1 was prepared, and it emulsified for 2 minutes on 10,000 rpm conditions using the homogenizer.

  This emulsion was charged into a 500 mL four-necked separable flask equipped with a thermometer, a stirrer, a nitrogen inlet tube, and a reflux condenser, and after adjusting the temperature to 50 ° C., the inside of the reactor was purged with nitrogen for 30 minutes. 0.12 g of dimethyl 2,2′-azobis (2-methylpropionate) was added, and the reaction was performed for 18 hours while adjusting the temperature to 50 ° C. 10.0 g of polyoxyalkylene alkyl ether (HLB 13.3, 2% by weight aqueous solution cloud point 64 ° C.) was added to and mixed with the reaction product to obtain a water-in-oil polymer emulsion to be used for the test. This was sample 1 and the composition is shown in Table 2.

(Production example 2 of water-in-oil polymer emulsion)
A water-in-oil polymer emulsion was obtained in the same manner as in Production Example 1 except that the polymer emulsifier 1 was changed to the polymer emulsifier 2 of Production Example 2. This was designated as Sample 2 and the composition is shown in Table 2.

(Production Example 3 of water-in-oil polymer emulsion)
A water-in-oil polymer emulsion was obtained in the same manner as in Water-in-oil type polymer emulsion Production Example 1 except that the polymer emulsifier 1 was changed to the polymer emulsifier 3 of Production Example 3. This was sample 3 and the composition is shown in Table 2.

(Production Example 4 of water-in-oil polymer emulsion)
The same method as in Production Example 1 for water-in-oil polymer emulsion, except that polyoxyethylene oleyl ether (n = 2) was changed to polyoxyalkylene alkyl ether (HLB 11.7, 2 wt% aqueous solution cloud point 18 ° C.) Thus, a water-in-oil polymer emulsion was obtained. This was sample 4, and the composition is shown in Table 2.

(Production Example 5 of water-in-oil polymer emulsion)
Without using the polymer emulsifier 1 added before emulsification, 5.0 g of polymer emulsifier is added in addition to the polyoxyalkylene alkyl ether (HLB13.3, 2% by weight aqueous solution cloud point 64 ° C.) added to the reaction mixture. A water-in-oil polymer emulsion was obtained in the same manner as in Production Example 1 of water-in-oil polymer emulsion, except that it was mixed. This was sample 5 and the composition is shown in Table 2.

(Production Example 6 of water-in-oil polymer emulsion)
Except for the fact that the aqueous phase was 202.5 g of 50% by weight acrylamide aqueous solution, 151.9 g of 65% by weight N, N, N, N-dimethyldiallylammonium chloride aqueous solution, 0.4 g of isopropyl alcohol, and 0.2 g of purified water. A water-in-oil polymer emulsion was obtained in the same manner as in Production Example 1 of water-in-water polymer emulsion. This was designated as Sample 6 and the composition is shown in Table 2.

(Production Example 7 of water-in-oil polymer emulsion)
The aqueous phase was 217.3 g of a 50 wt% aqueous acrylamide solution, 66.2 g of an 80 wt% acryloyloxyethyltrimethylammonium chloride aqueous solution, 28.3 g of an 80 wt% methacryloyloxyethyltrimethylammonium chloride aqueous solution, 19.7 g of an 80 wt% aqueous acrylic acid solution, A water-in-oil polymer emulsion was obtained in the same manner as in Production Example 1 for water-in-oil polymer emulsion except that 0.4 g of isopropyl alcohol and 23.1 g of purified water were used. This was designated as Sample 7 and the composition is shown in Table 2.

(Water-in-oil polymer emulsion comparative production example 1
Except that it was set as Comparative Polymer 1 in the oil phase, it was in oil except that it was 135.0 g of alicyclic saturated hydrocarbon (initial boiling point 242 ° C., end point 82.8 ° C., aniline point 82.8 ° C.). A water-in-oil polymer emulsion was obtained in the same manner as in Production Example 1 of water-type polymer emulsion. This was designated as Comparative Sample 1, and the composition is shown in Table 2.

(Water-in-oil polymer emulsion comparative production example 2)
A water-in-oil polymer emulsion was obtained in the same manner as in Production Example 1 for water-in-oil polymer emulsion, except that the polymer emulsifier 1 was used as the comparative polymer 2 in the oil phase. This was designated as Comparative Sample 2, and the composition is shown in Table 2.

(Table 1)
PEGAC: methoxypolyethylene glycol acrylate (n = 9), MMAE: dimethylaminoethyl methacrylate, EHAC: 2-ethylhexyl acrylate, AC: acrylic acid, AN: acrylonitrile Weight average molecular weight: Eluent by gel permeation chromatography Calculated value analyzed using tetrahydrofuran, standard polystyrene, column Shodex Asahipak GF-310 HQ

(Table 2)
Composition: (mol%)
AEM: acryloyloxyethyltrimethylammonium chloride, MEM: methacryloyloxyethyltrimethylammonium chloride, AC: acrylic acid, AM: acrylamide

A yield measurement test was performed using a bullet type dynamic jar tester using 200 mesh wire. The papermaking raw material used was a newspaper papermaking raw material having a solid content concentration of 1.0% by mass and containing 4.8% solid content concentration as Ash content such as light calcium carbonate. The physical properties of the papermaking raw materials are pH 7.2, Whatman No. The required amount of cation using a PCD-03 model of 41 filter paper filtrate manufactured by Mutech is 0.004 meq / L.

(Test 1)
The papermaking raw material was charged into the Brit type dynamic jar tester and stirred at 1500 rpm for 20 seconds. Assuming that the sample has passed through the screen, 150 ppm by weight of a 0.2 wt% aqueous solution obtained by stirring Samples 1 to 7 for 1 minute at 800 rpm using an 8 mm stirrer bar was added to the solid content of the paper and further stirred for 10 seconds. After discharging white water for 10 seconds with stirring, white water was collected for 10 seconds, 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. Table 3 shows the yield measurement results and the viscosity of a 0.2 wt% aqueous solution obtained by dissolving the test sample in water for 1 minute.

(Comparative test 1)
A yield measurement test was performed in the same manner as in Test 1 except that Sample 1 to Sample 7 were changed to Comparative Sample 1 and Comparative Sample 2. Table 3 shows the yield measurement results and the viscosity of a 0.2 wt% aqueous solution obtained by dissolving the test sample in water for 1 minute.

(Comparative test 2)
In addition to Sample 1 to Sample 7, Comparative Sample 1 and Comparative Sample 2 were used, except that the dissolution condition of the 0.2 wt% aqueous solution was set at 800 rpm for 60 minutes, and the time until white water was discharged after addition of the sample was 30 seconds. Conducted a yield rate measurement test in the same manner as in Test 1. Table 3 shows the yield measurement results and the viscosity of a 0.2 wt% aqueous solution obtained by dissolving the test sample in water for 1 minute.

(Table 3)

0.2 mass% aqueous solution viscosity (25 ° C., B-type viscometer measurement); mP · s

  By comparing Test 1 and Comparative Test 1, it is possible to assume a difference in the effect of adding a chemical after passing through the screen depending on whether or not the polymer emulsifier is used and the molecular weight of the polymer emulsifier. When Samples 1 to 7 are used, the yield effect is clearly better than when Comparative Sample 1 is used, and the solution viscosity of Comparative Sample 1 is extremely low, so that chemical addition is performed after passing through the screen. In this case, it can be seen that sufficient effects cannot be exhibited because the dissolution rate and the reaction rate to the pulp slurry are insufficient. Moreover, when the comparative sample 2 is used, it turns out that the improvement degree of a dissolution rate and the reaction rate to a pulp slurry is inadequate because the molecular weight of a polymer emulsifier is high.

  When Test 1 and Comparative Test 2 are compared, Comparative Test 2 has sufficient reaction time for dissolution and pulp slurry, so even when Comparative Sample 1 and Comparative Sample 2 are used, it is more effective than Comparative Test 1. Although the yield effect has been improved, it suggests that the effect cannot be fully exerted under any conditions when a strong share is applied such as adding chemicals in front of the screen. That is, when the water-in-oil polymer emulsion is added to the pulp slurry after passing through the screen, it is clear that Samples 1 to 7 are suitable and the maximum effect can be obtained.

In the newspaper paper machine, Comparative Sample 1 was added with 200 ppm of solid content before passing through the screen under conditions of a paper making speed of 1100 m / min and a basis weight of 43 g / m ^2. The polymer aqueous solution of the type polymer emulsion was placed in a place where “Trump Jet” of Wet End Technology Inc. having a form embodying the mixing means described in the present invention was placed after passing through the screen, Minutes were added. Before changing the addition method, the total wire yield was 45% and the ash yield was 25% when the water-in-oil emulsion polymer was used. On the other hand, after the addition method using the addition method used in the present invention and the change of the additive chemicals, the wire yield rate was improved to 48% and the ash content rate was improved to 30%. In addition, the texture was almost the same after the chemical addition method and the chemical change, and no decrease in texture was observed.

In the papermaking method described in Claim 1, it is a system diagram for adding the dispersion polymer in the salt solution used by this invention. In the papermaking method described in Claim 2, it is a system diagram for adding the dispersion polymer in the salt solution used by this invention.

1 White water circulated in the main papermaking raw material stream 2 Last screen 3 Papermaking chemical storage tank (yield improvement / paper quality improvement agent)
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 improvement / 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 (7)

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. A papermaking method in which the papermaking chemical is added to and mixed with the papermaking chemical, and then the papermaking chemical is a vinyl water-soluble monomer structural unit. A water-in-oil polymer emulsion containing a water phase containing a water-soluble polymer having a dispersed phase, an oil phase comprising a hydrocarbon solvent as a continuous phase, and a polymer having hydrophilic and hydrophobic structural units, and / or Or a papermaking method characterized by being a solution thereof. The papermaking method according to claim 1, wherein a surfactant having an HLB in the range of 1 to 9 is used in combination with the polymer having the hydrophilic and hydrophobic structural units. In addition to the polymer having the hydrophilic and hydrophobic structural units and the surfactant having an HLB in the range of 1 to 9, a surfactant having an HLB of 10 to 20 is used in combination. The paper making method described. The papermaking method according to any one of claims 1 to 3, wherein the polymer having hydrophilic and hydrophobic structural units has structural units represented by the following general formulas (1) and (2).

(R ₁ : hydrogen or methyl group R ₂ : hydrogen, alkyl group having 1 to 4 carbon atoms or phenyl group n: an integer of 2 to 100)
General formula (2)
(R ₃ : hydrogen or methyl group R ₄ : alkyl group having 4 to 18 carbon atoms, alkenyl group, aryl group or COOR ₅ , where R ₅ is an alkyl group having 4 to 18 carbon atoms) The polymer having hydrophilic and hydrophobic structural units is methoxy or phenoxypolyethylene glycol (polyoxyethylene unit polymerization degree is 3 to 23) (meth) acrylate 5 to 30 mol%, carbon number 4 to 18 alkyl group Alkyl (meth) acrylate 50-95 mol%, dialkylaminoalkyl (meth) acrylate 0-15 mol%, (meth) acrylic acid 0-15 mol% copolymer, the same hydrocarbon as the hydrocarbon solvent The papermaking method according to any one of claims 1 to 3, wherein the papermaking method is obtained by copolymerization in a system solvent. The papermaking method according to any one of claims 1 to 4, wherein the polymer having the hydrophilic and hydrophobic structural units has a weight average molecular weight in the range of 3000 to 50,000. The papermaking method according to claim 1, wherein the vinyl-based water-soluble monomer is represented by the following general formula (3) and / or (4) and / or (5).
General formula (3)
(R ₆ is hydrogen or a methyl group, R ₇ and R ₈ are alkyl or alkoxyl groups having 1 to 3 carbon atoms, R ₉ is hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkoxyl group, or a benzyl group. may be different, a is oxygen or NH, B represents an alkylene group or an alkoxylene group having 2 to 4 carbon atoms, X ₁ ^- represents respectively an anion).
General formula (4)
(R ₁₀ represents hydrogen or a methyl group, R ₁₁ and R ₁₂ 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 (5)
(R ₁₃ 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 ₁₄ represents hydrogen or COO ⁻ Y ⁺ , Y ⁺ and Y ₁ ⁺ each represents a hydrogen ion or a cation.)