WO1997023691A1

WO1997023691A1 - Papermaking process

Info

Publication number: WO1997023691A1
Application number: PCT/JP1996/003748
Authority: WO
Inventors: Tomonori Nakamura; Hideyuki Wakamatsu; Hidetoshi Sakamoto; Katsutoshi Tanaka
Original assignee: Hymo Corporation
Priority date: 1995-12-25
Filing date: 1996-12-24
Publication date: 1997-07-03
Also published as: DE69607394T3; CN1081705C; TW342418B; EP0877120B2; PT877120E; DE69607394T2; EP0877120B1; ES2146920T5; KR19990063915A; EP0877120A4; ATE191026T1; KR100422282B1; EP0877120A1; DE69607394D1; ES2146920T3; AU2011897A; CN1205756A

Abstract

A papermaking process comprising the steps of: adding, to pulp for papermaking in the step of transforming pulp into paper in papermaking, an ionic water-soluble polymer prepared by a method wherein polymerization is conducted in an aqueous salt solution capable of dissolving monomers and incapable of dissolving the resultant polymer in the presence of a dispersant comprising a polyelectrolyte soluble in this aqueous salt solution while stirring to prepare a dispersion of fine polymer particles; and adding an anionic additive selected among anionic colloidal silica, anionic (co)polymers, bentonite, and mixtures thereof, thereby improving the yield and/or drainage rate. This process can markedly improve the yield of raw material/filler and the drainage rate, realizing a high quality and a high productivity.

Description

Specification

Papermaking method Technical field

The present invention relates to a papermaking method in a papermaking process, and more particularly, to an ionizable water-soluble polymer, anionic colloidal silica, anionic (co) polymer, and a specific production method for papermaking pulp in the papermaking process of papermaking. The present invention relates to a sagami method for improving yield and drainage by adding an anionic additive selected from bentonite and a mixture thereof. Background art

Conventionally, in the papermaking process of papermaking, there has been a problem that the composition distribution in the thickness direction of the paper layer becomes uneven due to the outflow of various fillers added. In addition, there were also problems to be solved, such as an increase in cost due to the outflow of raw materials and additives, and the need for a stock concentration of a certain level or more. In addition, spillage of fillers and the like also leads to contamination of circulating white water. Certain retention aids have been added to solve these problems. Also, an increase in papermaking speed during papermaking leads to an increase in productivity, while an improvement in pulp refining degree is also desired from the viewpoint of increasing paper strength, but this conflicts with the papermaking speed and solves them at the same time. It was difficult. To solve this problem, a drainage improver has been added. As the retention improver or drainage improver, generally, a water-soluble polymer substance, that is, a polyacrylamide and a derivative thereof, a synthetic polymer substance such as polyethyleneimine, polyamidepolyamineepiclohydrin resin, or Starch and its Natural water-soluble polymer substances such as derivatives are used. Various methods have been proposed for the purpose of further improving the yield and Z or drainage. For example, a method of adding and mixing a cationic or amphoteric water-soluble polymer to a paper stock and then adding and mixing a colloidal silicic acid (Japanese Patent Application Laid-Open No. 3-27676) discloses a method of 25 to 60 mol%. A method of adding a cationic starch or polyacrylamide Hoffman reactant after adding an anionic acrylamide-based polymer having a molecular weight of 100,000 to 100,000 and containing a cationic anionic group to a stock. Japanese Patent Application Laid-Open No. 60-185900), a method using cationic starch and anionic colloidal silica (Japanese Patent Application Laid-Open No. 57-190900), acrylamide having a cationic group, (Japanese Patent Application Laid-Open No. 62-15991), a method of adding a colloidal silicic acid, a cationic or amphoteric polyacrylamide derivative, and a cationic starch ( Japanese Patent Application Laid-Open No. Sho 62-110109 A variety of proposals have been made, such as a method for improving the yield by using a cationic polymer and bentonite (Japanese Patent Application Laid-Open No. 62-191598). Also, a papermaking method in which a high molecular weight cationic polymer is first added to a papermaking cellulose slurry, and then a medium molecular weight anion polymer is added (Japanese Patent Application Laid-Open No. Hei 4-254998), and a cationic polymer flocculant is used. There has been known a method for improving a filler yield in which a mixture of an anionic polymer compound and bentonite is added after the addition and mixing of the stock (Japanese Patent Application Laid-Open No. S64-61588). Although these methods use water-soluble polymers alone, they have improved yield and drainage more than methods using water-soluble polymers alone.However, due to recent advances in papermaking technology and an increase in wastepaper usage, raw pulp has increased. It is not fully satisfactory due to the worsening situation and the deterioration of the quality of papermaking water, and there is a strong demand for a method for further improving the yield or filterability. An object of the present invention is to increase the yield of cellulose fibers and fillers in the papermaking process. The purpose is to improve productivity in the sandpaper process and the drying process by improving Z and drainage. To be more specific, it is necessary to average the composition distribution in the thickness direction of the paper layer to produce high-quality paper, to prevent outflow of raw materials and fillers, to reduce costs, and to make paper with a high degree of refining pulp. In such a case, the object is not to reduce the papermaking speed. Another object of the present invention is to improve the yield and / or to establish a stable papermaking method by keeping the circulating white water clean by improving drainage. It is a further object of the present invention to provide a papermaking method that reduces the load in the white water recovery step and the load in the wastewater treatment step by improving the yield and / or improving the drainage. Disclosure of the invention

The present inventors have conducted intensive studies in order to achieve these objects, and as a result, in the papermaking process of papermaking, added and mixed an ion-soluble water-soluble polymer obtained by the following dispersion polymerization method to paper stock, By adding and mixing an anionic additive selected from anionic colloidal silica, anionic (co) polymer, bentonite, and a mixture thereof, the papermaking method can improve the yield and Z or drainage. The inventors have found that the object can be achieved, and have reached the present invention. The dispersion polymerization method of the ionic water-soluble polymer used in the present invention includes: (A) a water-soluble cationic vinyl represented by the following formula (1) in an amount of 3 to 100 mol% in all monomers. Monomer or a mixture thereof, (B) 0 to 30 mol% of water-soluble anionic vinyl monomer in all monomers, and (C) a monomer comprising the remaining water-soluble nonionic vinyl monomer. In a salt aqueous solution in which the monomer is dissolved and the formed polymer is not dissolved, polymerization is carried out with stirring in the presence of a dispersant comprising a polymer electrolyte soluble in the salt aqueous solution. This is a polymerization method to obtain a dispersion of particles.

0 = CABN ⁺ -R ₄

R

(Where A is 0 or NH; B is C ₂ H ₄ , C ₃ H ₆ , C ₃ H ₅ OH; is H or CH ₃ ; R ₂ , R ₃ is CH ₃ or C ₂ H ₅ ; R ₄ represents H, CH ₃ , C ₂ H ₅ or a benzyl group; X represents an anionic counter ion.) That is, in the present invention, a monomer called a dispersion polymerization method is added to a papermaking pulp in a papermaking process. While dissolving but not dissolving the produced polymer, polymerization of a specific water-soluble vinyl monomer is carried out while stirring in a salt aqueous solution in the presence of a dispersant composed of a polymer electrolyte soluble in the salt aqueous solution. Then, an ionic water-soluble polymer produced by a polymerization method for obtaining a dispersion of fine polymer particles is added, and then anionic colloidal silica, anionic (co) polymer, bentonite and a mixture thereof are added. Add selected anionic additives to improve yield and / or improve drainage It is a papermaking method comprising Rukoto. The present invention also provides a method for preparing a salt solution, wherein the salt forming the aqueous salt solution used in the production of the ionic polymer used in the method is a divalent anion salt. . Further, in the present invention, it is preferable that the dispersant used in the production of the ionic polymer used in the method is 50 to 100 mol% of a salt of dimethylaminoethyl acrylate or dimethylaminoethyl methacrylate. Salt, dimethylaminopropyl acryla Mid salt, dimethylaminopropyl methacrylamide salt, acryloyloxyethyltrimethylammonium chloride, methacryloyloxyshethyltrimethylammonium chloride, acrylamide doprovir trimethylammonium One cation monomer selected from dimethyl chloride, methacrylamide doprovir trimethylammonium chloride, dimethyldiarylammonium chloride and mixtures thereof, and 0 An object of the present invention is to provide a papermaking method characterized in that it is a cationic polymer electrolyte obtained by polymerizing acrylamide of up to 50 mol%. Still further, the present invention is characterized in that the ionic water-soluble polymer in the above method has an intrinsic viscosity in a 2% by weight aqueous solution of ammonium sulfate of 5 d1 Zg to 30 d1. It provides a method. Further, in the present invention, the addition amount of the above-mentioned ionizable water-soluble polymer is 0.001 to 0.2% by weight per stock SS, and the total addition amount of the above-mentioned anionic additive is 0.00% per stock SS. It is intended to provide a papermaking method characterized in that the content is 1 to 0.5% by weight. Here, the addition amount of the ionic polymer is more preferably 0.001 to 0.05% by weight, and the total addition amount of the anionic additive is 0.01 to 0.2% by weight. is there. In the present invention, the anionic additive to be added after the addition and mixing of the ionic polymer is an anionic (co) polymer, and the composition of the anionic (co) polymer is based on the total monomers. An object of the present invention is to provide a papermaking method as described above, characterized in that it is a polymer of a monomer containing 15 to 100 mol% of acryloleic acid and 0 to 85 mol% of acrylamide. Further, the anionic additive to be added after the addition and mixing of the ionic polymer is an anionic (co) polymer, and the monomer is dissolved as the anionic (co) polymer. A papermaking method comprising conducting polymerization in an aqueous salt solution in which the produced polymer is not dissolved, and adding a water dilution of the obtained dispersion of polymer fine particles as the anionic additive. . Further, the present invention is characterized in that, in the above method, the ionizable water-soluble polymer is added before the centrifugal screen in the paper making process, and the anionic additive is added after the centriline. To provide a papermaking method. The present invention also provides the papermaking method according to the above method, wherein the ionic water-soluble polymer comprises 1 to 30 mol% of a water-soluble anionic vinylinole monomer in all monomers. is there. At this time, the anionic monomer is one selected from acrylic acid, methacrylic acid or a salt thereof, itaconic acid or a salt thereof, acrylamide 2-methylbutanepansulfonic acid or a salt thereof, and a mixture thereof. Is more preferable, and acrylic acid is most preferable. Further, in the present invention, in the above method, the gram equivalent number of the water-soluble vinyl monomer used in the ionic water-soluble polymer may be larger than that of the water-soluble anionic vinyl monomer. And a monomer composition. The present invention also provides a papermaking method according to the above method, wherein the ionic water-soluble polymer does not contain a water-soluble anionic vinyl monomer. Still further, the present invention provides a papermaking method, wherein the water-soluble nonionic vinyl monomer is acrylamide. Further, the present invention provides the above method, wherein the water-soluble cationic vinyl monomer is It is intended to provide a sagami method characterized by being a tertiary salt and / or quaternary compound of methylaminoethyl acrylate. BEST MODE FOR CARRYING OUT THE INVENTION

The method for producing an ionic water-soluble polymer used in the present invention comprises the steps of: dissolving the water-soluble ionic vinyl monomer to be used, but dissolving the formed ion-soluble water-soluble polymer in a salt aqueous solution; The monomer polymerization is carried out with stirring in the presence of a dispersant comprising a polymer electrolyte which is soluble in water, and the dispersion polymerization method is used to obtain the above-mentioned ionizable water-soluble polymer dispersion. Examples of the production method include the methods disclosed in European Patent Publication No. 1 834 666 and European Patent Publication No. 364 175. The present inventors have reported that ionic water-soluble polymers produced by a dispersion polymerization method in an aqueous salt solution can be produced by a conventional polymerization method having the same monomer composition, for example, an aqueous solution polymerization method, a water-in-oil emulsion polymerization method. Compared with the ionic water-soluble polymer produced in the above, when used together with an anionic additive selected from anionic colloidal silica, anionic (co) polymer, bentonite and a mixture thereof, the yield and The present inventors have found that Z or drainage is improved, and have reached the present invention. This is thought to be due to the nature of the dispersion polymerization method in an aqueous salt solution. In this polymerization method, before the polymerization, the monomers are uniformly dissolved in the aqueous salt solution as a polymerization solvent, but as the polymerization proceeds, the produced polymer separates and precipitates from the aqueous salt solution, Form a dispersion of fine particles with the aid of a dispersant. In other words, the phase separation force from a homogeneous phase to two phases is occurring. The mechanism of this polymerization has not been clearly elucidated, but it is a polymer with a special molecular structure that is different from the polymerization performed in a homogeneous phase, such as aqueous polymerization and water-in-oil emulsion polymerization. Many polymers or block copolymers It is expected that physical strength << generated. This particular difference in the molecular structure can be expected to be the factor that improves the yield and the water drainage. The water-soluble ionic vinyl monomer constituting the ion-soluble water-soluble polymer used in the present invention is represented by the following formula (1).

C Γ 2 ⁼ C− K 1 R 2

0 = C— A— B— N + — R ₄ · X- ·, · (1)

I

Ra

(Where A is 0 or NH; B is C ₂ H ₄ , C ₃ H ₆ , C ₃ H ₅ OH; is H or CH ₃ ; R ₂ , R ₃ is CH ₃ or C ₂ H ₅ ; R ₄ is H, CH ₃ , C ₂ H ₅ or a benzyl group; X— represents an anionic counter ion.) As the water-soluble cationic vinyl monomer represented by the above formula (1), particularly, Tertiary salt and / or quaternary compound of tilaminoethyl acrylate or dimethylaminoethyl methacrylate, or tertiary salt of dimethylaminopropyl acrylamide or dimethylaminopropyl methacrylamide and / or Alternatively, quaternized compounds are preferred.

The tertiary salt is typically a hydrochloride or sulfate of the monomer, and the quaternization is typically a methylation, ethylation and benzylation of the monomer. Specific examples of the water-soluble cationic vinyl monomer represented by the above formula (1) include acryloyloxhetyl dimethylbenzylammonium chloride and methacryloy. Loxoshetyl dimethylbenzylammonium chloride, acrylamide propyl dimethylbenzylammonium chloride, methacrylamide bromobenzyl dimethyl benzylammonium chloride, acryloyloxyshetyl trimethylammonium chloride, methacryloyl Quinethyl trimethylammonium chloride, acrylamidobrovir trimethylammonium chloride, methacrylamide Dopamine trimethylammonium chloride, dimethylaminoethyl acrylate hydrochloride or sulfate, dimethylamino Ethyl methyl chloride hydrochloride or sulfate, dimethylaminopropyl acrylamide hydrochloride or sulfate, dimethylaminopropyl methacrylamide hydrochloride or sulfate, etc. Can. Among them, particularly preferred water-soluble cationic vinyl monomers include acryloyloxyshethyldimethylbenzylammonium chloride as those containing a benzyl group, and acryloyloxyl as those containing no benzyl group. It is ethyltrimethylammonium chloride. Examples of the water-soluble anionic vinyl monomer used in the present invention include itaconic acid or a salt thereof, maleic acid or a salt thereof, fumaric acid or a salt thereof, an acrylic or methacrylic anionic monomer, or And mixtures thereof.

Representative examples of the acrylic or methacrylic anion monomer include, for example, acrylic acid, methacrylic acid or a salt thereof, 2-acrylamide 2-methylpropanesulfonic acid or a salt thereof, or a mixture thereof. It is. Among these, preferred water-soluble anionic vinyl monomers are acrylic acid and methacrylic acid, most preferably acrylic acid. Examples of the water-soluble nonionic vinyl monomer used in the water-soluble water-soluble polymer of the present invention include acrylamide, methylacrylamide, and hydroxyethylamine. Acrylate, hydroxyethyl methacrylate and the like. Acrylic amide is most preferably used in terms of yield as a papermaking chemical and improvement in z or drainage. The ionic water-soluble polymer used in the present invention comprises (A) a water-soluble cationic vinyl monomer represented by the above formula (1) in an amount of 3 to 100 mol% of all monomers or a water-soluble cationic vinyl monomer thereof. A mixture comprising (B) 0 to 30 mol% of a water-soluble anionic vinyl monomer in all monomers, and (C) a monomer having a monomer composition ratio of the remaining water-soluble nonionic vinyl monomer. It is obtained by polymerizing. As the above-mentioned zwitterionic water-soluble polymer used in the present invention, a zwitterionic or amphoteric water-soluble polymer is preferably used. Anionic additives selected from anionic colloidal silica, anionic (co) polymers, bentonite and mixtures thereof are anionic and anionic or nonionic as a pre-added polymer to paper stock The use of water-soluble polymers is not preferred. In the case where the above-mentioned zwitterionic water-soluble polymer is a water-soluble zwitterionic water-soluble polymer, it may be selected from among the vinyl monomers represented by the above formula (1), which contain a benzyl group. A homopolymer, a plurality of types of vinyl monomers represented by the above formula (1), or those obtained by further copolymerizing a water-soluble nonionic vinyl monomer such as acrylamide or methacrylamide are more preferable. preferable. The preferred molar ratio of these monomers is not particularly limited, but the molar ratio of the monomers in which the formed ionic water-soluble polymer does not dissolve in the aqueous salt solution as the polymerization solvent, that is, the salting out is essential. Condition. For example, a preferable range thereof is a water-soluble cationic compound represented by the above formula (1). Among the vinyl monomers, a water-soluble cationic vinyl monomer containing a benzyl group or a mixture thereof 3 to 100 mol%, and other water-soluble compounds represented by the above (1) not containing a benzyl group The molar ratio is such that the polymer of the monomer comprising the cationic vinyl monomer or a mixture thereof at 0 to 50 mol% and the remaining nonionic monomer undergoes salt breakage. The monomer containing a benzyl group in the water-soluble cationic vinyl monomer of the above formula (1) has a strongly hydrophobic benzyl group bonded to an amino group, and as a result, despite the water-soluble polymer, It is difficult to dissolve in salt solution. Therefore, when the component of the cationic water-soluble polymer contains the benzyl group-containing water-soluble cationic vinyl monomer of the above formula (1), it is represented by the above formula (1) containing no benzyl group. It is possible to set the molar ratio to other water-soluble ionic vinyl monomers in a wide range. On the other hand, in the case of a cationic water-soluble polymer having a water-soluble cationic vinyl monomer represented by the above formula (1) containing no benzyl group as a water-soluble cationic vinyl monomer as a constituent element, The molar ratio of the water-soluble cationic vinyl monomer to acrylamide or methylacrylamide is preferably in the range of 3:97 to 30:70. As the ionic water-soluble polymer used in the present invention, the amphoteric water-soluble polymer is a water-soluble cationic vinyl monomer represented by the above formula (1) or a mixture thereof in an amount of 3 to 99% by mole, and the water-soluble anion. More preferably, a copolymer of 1 to 30 mol% of a water-soluble vinyl monomer and the remaining water-soluble nonionic vinyl monomer, for example, acrylamide or methacrylamide is used. The preferred molar ratio of these monomers is not particularly limited. The molar ratio of the monomers is such that the polymer produced does not dissolve in the aqueous salt solution as a polymerization solvent, that is, the monomer is salted out. However, in order to exhibit the characteristics of amphoteric water-soluble polymers, cations and anions must be added. It is preferable that the total amount of the contained vinyl monomer contained in the copolymer is 5 mol% or more, more preferably 10 mol% or more. If the total amount of the ionic vinyl monomer is less than 5 mol% in the copolymer, various properties such as yield and drainage become insufficient. Further, regarding the molar ratio of each ionic vinyl monomer, since the number of cation groups in the amphoteric copolymer is preferably larger than the number of anionic groups, the gram equivalent value of the water-soluble ionic vinyl monomer is preferably It is preferably larger than the gram equivalent value of the water-soluble anionic vinyl monomer. Particularly preferably, the cationic group has at least twice the gram equivalent value of the anionic group. More preferable examples of the amphoteric water-soluble polymer include, for example, a water-soluble cationic vinyl monomer having a benzyl group among the water-soluble cationic vinyl monomers represented by the above formula (1). Or 3 to 99 mol% of a mixture thereof, not containing a benzyl group, other water-soluble cationic vinyl monomer represented by the above (1) or a mixture of 0 to 50 mol% thereof, and a water-soluble anionic vinyl monomer alone. 1 to 30 mol% of a monomer, and a dispersion copolymer of a monomer in which a monomer other than the above-mentioned components in all monomers is acrylamide.

Other preferable examples of the amphoteric water-soluble polymer include, for example, a water-soluble cationic vinyl monomer represented by the above formula (1) containing no benzyl group or a mixture of 3 to 30 moles thereof. %, Anionic monomer of 1 to 30 mol%, and a monomer-dispersed copolymer of acrylamide in which all the monomers other than the above-mentioned components in all monomers are acrylamide. Further, other monomers such as acrylonitrile, methyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate, and hydrophobic substances such as styrene. If the resulting copolymer is also water-soluble, it is possible to carry out copolymerization. The polymerization is carried out while stirring a plurality of monomers in an aqueous salt solution in the presence of a dispersant. The monomer concentration at this time is preferably 5% by weight or more, more preferably 10% by weight or more, and 40% by weight is particularly preferred. If the monomer concentration is less than 5% by weight, the polymer concentration in the dispersion becomes low, which is not economically preferable. It is an important condition that the polymerization product is not dissolved, that is, salted out, of the aqueous salt solution, which is a polymerization solvent during the production of the polymer used in the present invention and is a dispersion medium. That is, the combination of the monomer composition of the ionic water-soluble polymer, the type of salt, and the salt concentration that satisfies this condition is important. As the salt used in the salt aqueous solution, a polyvalent anion salt is preferable. Typical examples thereof include sodium sulfate, ammonium sulfate, magnesium sulfate, aluminum sulfate, and disodium hydrogen phosphate. Salts other than these can be used as long as they dissolve the monomer and the dispersant and do not dissolve the polymerization product. Of these, sulfates are preferred. In terms of valence, divalent anion salt is preferable. Specifically, ammonium sulfate and sodium sulfate are particularly preferred. The salt concentration in the reaction solution at the time of polymerization depends on the molar ratio of the water-soluble cationic vinyl monomer and the water-soluble anionic vinyl monomer represented by the above formula (1), and the type of salt used. There is no particular limitation because it differs depending on the location.

However, the salt concentration in the reaction solution during the polymerization is usually 15% by weight or more based on the weight of the polymerization reaction solution excluding the weight of the monomer, up to the saturation concentration or the solubility. Is more preferably 15% by weight or more and 30% by weight or less, particularly preferably 15% by weight or more and 25% by weight or less. If the salt concentration is less than 15% by weight, the viscosity of the reaction solution during the reaction increases, and the polymerization becomes difficult. The salt is added to the solvent during the polymerization to carry out the polymerization, but a part of the salt may be added to the dispersion after the completion of the polymerization. Rather than adding the salt to the solvent at the time of polymerization and performing polymerization at a time, the addition of the-part of the salt to the dispersion after the polymerization is completed can reduce the viscosity of the dispersion. The salt concentration in the dispersion obtained by adding a part of the salt to the dispersion after completion of the polymerization is preferably at least 15% by weight, up to the saturation concentration or up to the solubility limit, more preferably 15 to 2%. 5% by weight. Monomer of L-soluble water-soluble polymer that does not salt out the polymerization product even if various kinds of salts and salt concentrations are changed and that does not cause salt formation of the polymerization product The combination of body composition and salt type and concentration is inappropriate. A prerequisite is that the polymer electrolyte dispersant coexisting during the polymerization be soluble in an aqueous salt solution. As the polymer electrolyte, a cationic polymer is preferable as the ionic polymer as a product, and in the case of an amphoteric polymer, the gram equivalent value of the cationic monomer in the amphoteric polymer is that of the anionic monomer. It is preferable that the value be larger than the gram equivalent value. Therefore, it is preferable to use a cationic polymer electrolyte. Examples of the dispersant include 50 to 100 mol% of a salt of dimethylaminoethyl acrylate, a salt of dimethylaminoethyl methacrylate, a salt of dimethylaminopropyl acrylamide, a salt of dimethylaminopropyl acrylamide, Burimetacrylamide salt, acryloyloxetil trimethylammonium chloride, methacryloyloxetil trimethylammonium chloride, acrylic acid A cationic monomer selected from midpropyltrimethylammonium chloride, methacrylamide propyltrimethylammonium chloride, dimethyldiarylammonium chloride and mixtures thereof, and A cationic polymer electrolyte obtained by polymerizing 50 to 0 mol% of acrylamide is more preferable. The amount of the polyelectrolyte dispersant is about 1 to 15% by weight, more preferably about 1 to 10% by weight, based on the amount of all monomers. If the amount is less than 1% by weight, the polymerization product is not obtained in a dispersed state, and is undesirably adhered to each other to form a large mass. Use of an amount exceeding 15% by weight is not preferable because the viscosity of the finally obtained dispersion itself becomes high and the fluidity may be lost. In the present invention, any known method may be used to initiate the polymerization reaction as long as the obtained polymer is in a dispersion state. However, it is preferred to use a polymerization initiator. The selection of the polymerization initiator is not particularly limited, and generally, a free radical initiator is preferably used. These polymerization initiators are appropriately selected from redox, azo, and other types. Redox initiators include ammonium peroxosulfate, potassium peroxosulfate, hydrogen peroxide, and benzoyl peroxide, and sodium hydrogen sulfite, ferrous sulfate, ferrous sulfate, tetramethylethylenediamine, and dimethylaniline. Combinations with heels can be mentioned. As azo initiators, 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2′-azobis [2- (2-imidazoline-l-2-yl) propane] dihydrochloride, 2'-azobisisobutyronitrile, 2,2'-azobis (2,4-dimethylvaleronitrile), and 2,2'-azobis (4-methoxy2,4-dimethylvaleronitrile) ) And the like. Other types of initiators include ammonium peroxosulfate, potassium peroxosulfate, hydrogen peroxide, acetyl peroxide, lauroyl peroxide, benzoyl peroxide, cumenehydropa —Oxide, di-n-tert-butyl peroxide, tetramethylthiuram disulfide, dibenzoyl disulfide, p-toluenesulfonic acid and the like.

Furthermore, in the present invention, there is no particular limitation on the polymerization temperature as long as the polymerization initiator acts properly at the selected temperature. Examples of the type of the polymerization initiator include 2,2′-azobis (2-amidinopropane) dihydrochloride and 2,2′-azobis [2- (2-imidazoline-1-yl) propane] dihydrochloride. It is preferably used in terms of handling, controllability and the like. The concentration of the ion-soluble water-soluble polymer in the polymer dispersion is as high as 5% by weight or more, usually from 5% by weight to about 40% by weight. The above-mentioned salt and the above-mentioned dispersant are contained in the dispersion. Although the above dispersion contains a high concentration of an ionizable water-soluble polymer, the viscosity of the ionizable water-soluble polymer is low because the ionizable water-soluble polymer is stably dispersed in a fine particle state in an aqueous salt solution, and is usually 10 to 3000 mP The low viscosity of a · S makes it easy to flow and very easy to handle. The average particle size of the ionic water-soluble polymer particles in the dispersion is usually 0.1 to 150 m, preferably 0.1 to 50 / zm, more preferably 0.1 to 30 m. If the average particle size of the ionic water-soluble polymer particles exceeds 150, precipitation tends to occur, resulting in poor storage stability.In addition, the ionic water-soluble polymer particles are large even when mixed with water when the dispersion is used. It is poorly soluble in water and takes a long time to completely dissolve. The molecular weight of the ion-soluble water-soluble polymer in the above dispersion is not particularly limited. But, When used in the papermaking process of papermaking, the molecular weight is preferably large. When a dispersion of an ionic water-soluble polymer is dissolved in a 2% by weight aqueous solution of ammonium sulfate, the intrinsic viscosity of the polymer is usually in the range of about 5 dl / g to 30 dl Zg. If the intrinsic viscosity is less than 5 dl Zg, the effect of improving the yield and / or drainage is insufficient, and if it is greater than 30 dl Zg, the texture deteriorates and the product quality is adversely affected. The above dispersion is excellent in storage stability, and does not cause inconvenience such as particles adhering to each other to form a lump even when stored at room temperature. The anionic additive used in the present invention is selected from anionic colloidal silica, anionic (co) polymer, bentonite and a mixture thereof. The anionic colloidal silica used in the present invention is produced by maintaining an aqueous solution of soda orthogeate at pH 1 to 4, and those which are generally distributed as commercial products can be used. . The anionic colloidal silicide force is a silicon dioxide having 0H groups on the surface due to hydration in water, and its particle surface is porous and generally negatively charged in water. Specifically, for example, a surface area of about 50 to about 1000 m ² g, preferably about 300 to about 70 O m ² Zg described in JP-A-57-5190 And colloidal silicic acid containing about 20 to 90% of this colloidal gay acid sol. In addition, an elongated shape having an almost uniform thickness in the range of about 5 to 20 nm, extending only in one plane, and having a particle diameter of about 40 to 300 nm by a dynamic light scattering method, Anionic silica sols having a shape can also be preferably used. Use bentonite that is normally distributed as a commercial product. Can be. An anionic (co) polymer is a (co) polymer containing an anionic monomer containing an anionic substituent in the monomer. At this time, as the anionic monomer, acryloic acid, methacrylic acid or a salt thereof, itaconic acid or a salt thereof, maleic acid or a salt thereof, fumaric acid or a salt thereof, acrylamide 2-methylpropanesulfonic acid Alternatively, it is preferably selected from a salt thereof and a mixture thereof. The most preferred anionic monomer is acrylic acid, that is, the acrylic (co) polymer is preferably used as the anionic (co) polymer. Further, other monomers, such as nonionics such as methacrylamide, acrylonitrile, methacrylonitrile, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, hydroquinethyl acrylate, and hydroxyethyl methacrylate. It is also possible to copolymerize a hydrophilic monomer. As the atrial acid (co) polymer, preferably, the composition is a polymer of a monomer containing 15 to 100 mol% of acrylic acid and 0 to 85 mol% of acrylamide in all monomers. It is preferably an object. The method for producing the anionic (co) polymer used in the present invention is not particularly limited, and can be produced by a conventionally known method. Among them, a polymerization method is preferred in which the monomer is dissolved but the resulting (co) polymer is polymerized in an aqueous salt solution that does not dissolve the polymer to obtain polymer fine particles. The molecular weight of the resulting anionic (co) polymer is preferably at least 150,000. A water dilution of the polymer thus obtained is added to the stock. In the papermaking process, the amount of the ionizable water-soluble polymer added is from 0.001% to 0.2% by weight per SS of the paper material, and the total amount of the anionic additives added is the paper material. 0.001% to 0.5% by weight per SS is preferred. Further, the addition amount of the ionic water-soluble polymer is from 0.001% to 0.05% by weight per SS of the stock, and the total power of the addition amount of the anionic additives is less than 0% per SS of the stock. More preferred is from 0.1% to 0.2% by weight. If the added amount of the chemical is too small, the effect is reduced, and if it is too large, the felt or wire used in the papermaking process tends to be contaminated. In the papermaking method according to the present invention, the timing of adding each additive is not particularly limited, but an ionic water-soluble polymer is first added, followed by anionic colloidal silica, anionic (co) polymer, It is necessary to add an anionic additive selected from bentonite and a mixture thereof. Preferably, in the papermaking process, an ionic water-soluble polymer is added before the centriscreen in the papermaking process, and the anion is selected from anionic colloidal silica, anionic (co) polymer, bentonite and a mixture thereof. It is preferred to add the ionic additive after centriscreening.

After the addition of the zwitterionic water-soluble polymer, it is preferred that the polymer be evenly distributed on the surface of the suspended substance by moderate shearing. After the addition of the anionic additive selected from anionic colloidal silica, anionic (co) polymer, bentonite, and a mixture thereof, it is desirable to avoid destruction of aggregates due to excessive strong stirring. According to the present invention, an ionic water-soluble polymer produced by a dispersion polymerization method in an aqueous salt solution has the same monomer composition as a conventional polymerization method, for example, an aqueous solution polymerization method, a water-in-oil emulsion. Compared with the ionic water-soluble polymer produced by the polymerization method, when used in combination with an anionic additive selected from anionic colloidal silylicity, anionic (co) polymer, bentonite and mixtures thereof As described above, in the dispersion polymerization method in an aqueous salt solution, the produced polymer separates and precipitates as the polymerization proceeds in the aqueous solution of the aqueous salt solution, which is a polymerization solvent, as described above. . This results in a polymer with a steric molecular structure different from that in which the polymerization is carried out in a uniform phase, for example, a polymer with many branches.This difference in the steric molecular structure results in yield and / or drainage. Can be expected to be a factor improving Example

Next, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist.

(Example of preparation of ionic polymer)

(No. 1-6)

In a 1-liter, 5-neck, separable flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen inlet tube, 4.2 g of polyacryloyloxyshethyltrimethylammonium chloride as a dispersant and sulfuric acid as a precipitant The ammonia was taken in 84 g and dissolved in ion exchanged water. To this, 100 g of a monomer having the composition shown in Table 1 was charged, and the atmosphere was replaced with nitrogen while heating to 50 ° C. To this was added 2.O g of a 1% aqueous solution of 2,2'-azobis (2-amidinopropane) dihydrochloride as a polymerization initiator, and the mixture was polymerized at 50 ° C for 10 hours with stirring to disperse in a salt aqueous solution. Thus, a polymer of fine particles was obtained. To this reaction solution, 21 g of ammonium sulfate was added and dissolved to obtain dispersion polymer samples A to F used in the present invention.

Monomer composition of dispersed polymer samples A to F and 2% by weight aqueous ammonium sulfate solution Table 1 shows the intrinsic viscosity in the liquid.

(No. 7 to 12)

Similarly, comparative samples a to f shown in Table 1 were obtained by aqueous solution polymerization and reverse emulsion polymerization using monomers having the composition shown in Table 1 for specific drawing.

Table 1 shows the monomer composition of Comparative Samples a to f and the intrinsic viscosity in a 2% by weight aqueous solution of ammonium sulfate.

【table 1】

* ABC: Acryloyloxetyl dimethylbenzylammonium chloride DMQ: Acryloyloxetyl trimethylammonium chloride

A Λ c: acrylic acid A Am: Acrylamide (Example of preparation of acrylic acid (co) polymer)

In a 500-ml five-separable flask equipped with a stirrer, reflux condenser, thermometer, and nitrogen inlet tube, add 15.5 g of deionized water and 50% by weight of an aqueous acrylamide solution. 96 g, acrylic acid 12 g, and sodium sulfate 46.5 g were charged, the temperature was adjusted to 25 ° C. on a water bath, and the atmosphere was replaced with nitrogen for 30 minutes while stirring. As a polymerization initiator, 0.6 milliliter of an aqueous solution of ammonium persulfate having a concentration of 10% by weight and 0.6 milliliter of an aqueous solution of sodium bisulfite having a concentration of 10% by weight are added, and polymerization is carried out with stirring. And became cloudy after 2 minutes. At this point, when the water bath was removed, about 70 minutes after 30 minutes due to the heat of polymerization. Become C. Thereafter, the polymerization temperature was maintained at 70 ° C for 2 hours in a water bath to complete the polymerization reaction. The viscosity of the acrylic acid / acrylamide copolymer thus obtained was 320 mPa's using a Brookfield viscometer, and as a result of microscopic observation, a dispersion of a sphere having an average flow of 5 m was obtained. Had become. This dispersion (polymer concentration: 20% by weight) was diluted 40 times with deionized water, and the viscosity was measured with a Brookfield viscometer. The result was 3. OmPa · s, and the polymer was dissolved. I didn't. This polymer was neutralized with sodium hydroxide, and the intrinsic viscosity in a 1N aqueous solution of sodium chloride was measured. As a result, it was 6. OdlZg. This dispersion of acrylic acid-acrylamide copolymer is referred to as Sample G. Also, a homopolymer dispersion of acrylic acid was prepared in the same manner. This dispersion is designated as Sample H. The intrinsic viscosity of the neutralized product of Sample H in a 1 N aqueous sodium chloride solution was 6.1 d 1 / g. (Examples 1 to 14)

A test was conducted in which the ionic polymer dispersions (A) to (F) were added to the stock to measure the yield. Hardwood bleached kraft pulp (L-ΒΚΡ) [Canadian 'Standard' French (C.S.F.) = 330] 15% by weight heavy calcium carbonate as filler

(Relative to pulp) was added to adjust the S 2 S concentration to 0.5% by weight.

Using this slurry, the yield was measured by a brit-type dynamic jar tester. The test was performed in the following procedure.

0.5% by weight of 500m 1 is charged into a split-type dynamic jar tester.

Stirring is started at 1500 rpm, and a 0.1% by weight aqueous solution of the cationic polymer obtained in Preparation Example is added. Timing starts from this time.

After 30 seconds, 0.1% by weight of bentonite (trade name: Organozo-Boo 0, manufactured by Allied Colloids) and 0.1% by weight of anionic colloidal silica (trade name: BMA-780, manufactured by Nissan Eka Nobel) ) Is added.

After an additional 30 seconds, open the cock for collecting white water and let the white water that has passed through 150 mesh water flow.

Discard the white water for the first 10 seconds, and then collect the white water for 30 seconds. The amount of white water during this time is assumed to be Xm1.

This white water was filtered through a quantitative filter paper (Toyo Roshi Kaisha NO. 5C), whose dry weight (W.g) at 105 ° C was measured in advance, dried at 105 ° C, and weighed. Measure. This weight is Wig.

Next, incinerate at 600 ° C and measure the ash weight. This weight is assumed to be fg. Calculate the SS concentration and ash concentration in the white water by the following formula ₍

Wl one Wo

White water S S concentration (% by weight) = X 100 = S Si

X f

Ash content in white water (% by weight) = X I 00 = A s h!

X

For the 0.5 wt% stock, measure the SS concentration and ash concentration in the same manner. SS ₀ and Asho, respectively.

The total yield and the filler yield are determined by the following equations.

Total yield = X 100

(T-OPR%) S So

Λ s h o- A s h i

Filler yield = X 100

(F-0PR%) Asho The results obtained are summarized in Table 2. [Table 2]

(Comparative Examples 1 to 14)

The procedure of Example 1 was repeated, except that the polymer dispersions (A) to (F) were replaced by the solution polymerization polymer and the emulsion-type polymers ( _a ) to (f). The yield was measured in the same manner as in Examples 1 to 14. The results are shown in Table 3. Table 1 shows the composition and properties of the polymer. [Table 3]

(Examples 15 to 30)

Using the ionic polymer dispersions (A) to (F) used in Examples 1 to 14, instead of anionic colloidal silica and / or bentonite, an acrylic acid (co) polymer sample (G ), (H) and / or bentonite, and the yield was measured in the same manner as in Examples 1 to 14. The obtained results are also shown in Table _4c [Table 4]

(Comparative Examples 15 to 30)

Using ionic polymers (a) to (f) used in Comparative Examples 1 to 14, acrylic acid (co) polymer samples (G), (H) instead of anionic colloidal silica and no or bentonite And Comparative Examples 1-1 The yield was measured in the same manner as in 4. Table 5 also shows the obtained results.

[Table 5]

(Examples 31 to 44)

The ionic polymer dispersions (A) to (F) were added to papermaking pulp to conduct a drainage test. Corrugated cardboard waste paper: Newspaper waste paper = 90:10 mixed pulp (CS F = 300) was adjusted to a pulp concentration of 1% by weight, and a liquid sulfuric acid band was added at 3% by weight (based on pulp) to adjust the pH to 5.8. .

The slurry (30 Om1) was collected in a 50 Om1 beaker, and stirred with a three-one motor at 600 rpm to obtain a polymer (A) to (F) obtained in Preparation Examples 1 to 6. Add 1% by weight aqueous solution. After 30 seconds, 0.1% by weight of anionic colloidal silica and Z or 0.1% by weight of bentonite are added. After a further 30 seconds, stop stirring and transfer this slurry to the 1 liter graduated cylinder. After adjusting the total amount to 1 liter with Shimizu, invert the mixture 3 times and put it in Canadian Standard Freeness Tester. Measure the amount of filtrate flowing out to the side pipe according to the procedure of C.S.

Table 6 shows the obtained results.

[Table 6]

40 D 300 0 500 495

41 E 300 0 500 505

42 F 300 0 500 502

43 A 300 1 00 300 5 1 3

44 D 300 1 00 300 570

(Comparative Examples 31-44)

In the same manner as in Examples 31 to 44, ionic polymers (a) to (f) were used instead of the polymer dispersions (A) to (F) used in Examples 31 to 44, Measure the drainage and i <^-o

The results are shown in Table 7.

[Table 7]

Ionic anionic co-D idabentonite

Comparative example Polymer Addition amount

Type Addition amount 翻 inversion SS) (删 SS) (m l)

SS) (ppm) (ppm) (ppm)

3 1 a 200 200 0 442

32 b 200 200 0 452

33 c 200 200 0 446

34 d 200 200 0 435

35 e 200 200 0 455

36 f 200 200 0 443

37 a 300 0 500 460

38 b 300 0 500 465

39 c 300 0 500 463

40 d 300 0 500 450 41 e 300 0 500 470

42 f 300 0 500 460

43 a 300 100 300 470

44d 300 100 300 462

(Examples 45-60)

Using the ionic polymer dispersions (A) to (F) used in the actual Sfi Examples 31 to 44, instead of anionic colloidal silica and / or bentonite, an acrylic acid (co) polymer sample (G ), (H) and / or bentonite, and the drainage amount was measured in the same manner as in Examples 31 to 44. The results obtained are also shown in Table 8.

[Table 8]

Ionic bentonite sample. Sample H

Example Polymer Addition amount Addition amount Addition amount Drainage amount

Type addition amount (vs. Iffl (thigh SS) (gut SS) SS) (m 1)

SS) (ppm) (ppm) (ppm) (ppm)

45 A 250 0 150 0 478

46 B 250 0 150 0 472

47 C 250 0 150 0 482

48 D 250 0 150 0 478

49 E 250 0 150 0 480

50 F 250 0 150 0 470

51 A 250 0 0 150 476

52 B 250 0 0 150 474

53 C 250 0 0 150 480

54 D 250 0 0 150 480 55 E 250 0 0 150 478

56 F 250 0 0 150 474

57 A 250 250 80 0 513

58 D 250 250 80 0 505

59 A 250 250 0 80 514

60 D 250 250 0 80 506

(Comparative Examples 45-60)

J Using the ionic polymers (a) to (f) used in Comparative Examples 31 to 44, instead of anionic colloidal silica and Z or bentonite, acrylic acid (co) polymer samples (G) and (H) Y and Z or bentonite were used to measure the yield in the same manner as in Comparative Examples 31 to 44. The results are shown in Table 9. [Table 9]

5 4 d 2 5 0 0 0 1 5 0 4 4 0

5 5 e 2 5 0 0 0 1 5 0 4 4 6

5 6 f 2 5 0 0 0 1 5 0 4 4 4

5 7 a 2 5 0 2 5 0 8 0 0 4 8 3

5 8 d 2 5 0 2 5 0 8 0 0 4 7 5

5 9 a 2 5 0 2 5 0 0 8 0 4 8 4

6 0 d 2 5 0 2 5 0 0 8 0 4 7 6 Industrial applicability

According to the papermaking method of the present invention, it is possible to improve the yield of cellulose fibers and fillers and / or improve drainage in the papermaking process, thereby improving the productivity in the papermaking process and the drying process. Can be. Further, the papermaking method of the present invention can keep the circulating white water clean, and can further reduce the load in the white water recovery step and the load in the wastewater treatment step.

Claims

The scope of the claims

1. In the papermaking process of papermaking, it is added to the stock and mixed with the ionic water-soluble polymer obtained by the following process, and then selected from anionic colloidal silica, anionic (co) polymer, bentonite and mixtures thereof. A papermaking method for improving retention and z or drainage by adding and mixing an anionic additive, wherein the production process of the ionizable water-soluble polymer is (A) 3 to 100% of all monomers. Mol% of a water-soluble cationic vinyl monomer represented by the following formula (1) or a mixture thereof: (B) 0 to 30 mol% of a water-soluble anionic vinyl monomer in all monomers; The remaining monomer composed of a water-soluble nonionic vinyl monomer is dispersed in a salt aqueous solution that dissolves the monomer and does not dissolve the formed polymer, and is composed of a polymer electrolyte that is soluble in the salt aqueous solution. In the coexistence of the agent, with stirring Performed if, Sha sheet wherein that it is a polymerization method for obtaining a dispersion of fine polymer particles.

^{_{0 = CABN + -R 4 · X}} (1)

R;

(Where A is 0 or NH; B is C ₂ H ₄ , C ₃ H ₆ , C ₃ H ₅ OH; R _t is H or CH ₃ ; R ₂ , R ₃ is CH ₃ or C ₂ H ₅ ; R ₄ is Π, CH ₃ , C ₂ H ₅ or a benzyl group; X— represents an anionic counter ion.

2. The papermaking method according to claim 1, wherein the salt forming the aqueous salt solution is a divalent anion salt.

3. The dispersant is 50 to 100 mol% of a salt of dimethylaminoethyl acrylate, a salt of dimethylaminoethyl methacrylate, a salt of dimethylaminopropyl acrylamide, or a salt of dimethylaminoethyl acrylamide. Salt, acryloyloxetyltrimethylammonium chloride, acryloyloxetyltrimethylammonium chloride, acrylamide propyl trimethylammonium chloride, methacrylamide propyltrimethylammonium chloride One cationic monomer selected from dimethyl chloride, dimethyldiarylammonium chloride and mixtures thereof, and a cationic polymer electrolyte obtained by polymerizing 0 to 50 mol% of acrylamide 3. The papermaking method according to claim 1 or 2, wherein:

4. The ionic water-soluble polymer according to any one of claims 1 to 3, wherein an intrinsic viscosity in a 2% by weight aqueous solution of ammonium sulfate is 5 dl, g to 30 d 1 / g. Papermaking method described in Crab

5. The addition amount of the ionic polymer is 0.001 to 0.2% by weight per stock SS, and the total addition amount of the anionic additives is 0.001 to 0.5% by weight per stock SS. The papermaking method according to any one of claims 1 to 4, characterized in that:

6. The amount of the ionic polymer added is 0.001 to 0.05% by weight per paper SS, and the total amount of the anionic additive is 0.01 to 0.2% by weight per paper SS. 6. The papermaking method according to claim 5, wherein:

7. The anionic additive added after the addition and mixing of the anionic polymer is an anionic (co) polymer, and the composition of the anionic (co) polymer is such that 7. The polymer according to claim 1, wherein the monomer is a polymer containing 15 to 100 mol% of phosphoric acid and 0 to 85 mol% of acrylamide. Papermaking method as described.

8. The anionic additive to be added after the ionic polymer is added and mixed is an anionic (co) polymer, and as the anionic (co) polymer, a monomer is dissolved to dissolve the formed polymer The polymerization is carried out in an aqueous salt solution, and a water dilution of the obtained dispersion of polymer fine particles is added as the anionic additive. Item 14. The papermaking method according to any one of the above items.

9. The method according to claim 1, wherein the ionizable water-soluble polymer is added before the center screen in the papermaking process, and the anionic additive is added after the centriline. Item 14. The papermaking method according to any one of the above items.

10. The ionic water-soluble polymer according to claim 1, wherein the water-soluble anionic vinyl monomer comprises 1 to 30 mol% of all monomers. A papermaking method according to any one of clauses 9.

1 1. The anionic monomer is selected from acrylic acid, methacrylic acid or a salt thereof, itaconic acid or a salt thereof, acrylamide-1-methylpropanesulfonic acid or a salt thereof, and a mixture thereof. 10. The papermaking method according to claim 10, wherein the papermaking method is a seed.

12. The papermaking method according to claim 11, wherein the anionic monomer is acrylic acid.

1 3. The gram equivalent number of the water-soluble cationic vinyl monomer used in the ionic water-soluble polymer is larger than the gram equivalent number of the water-soluble anionic vinyl monomer, and the monomer composition. The papermaking method according to any one of claims 1 to 12, characterized by the following.

14. The papermaking method according to any one of claims 1 to 9, wherein the ionic water-soluble polymer does not contain a water-soluble anionic vinyl monomer.

15. The papermaking method according to any one of claims 1 to 14, wherein the water-soluble nonionic vinyl monomer is acrylamide.

16. The water-soluble cationic vinyl monomer is a tertiary salt of dimethylaminoethyl acrylate and a quaternary or quaternary compound. The papermaking method according to any one of the above.