Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
  • D21H17/20—Macromolecular organic compounds
  • D21H17/33—Synthetic macromolecular compounds
  • D21H17/34—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D21H17/41—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing ionic groups
  • D21H17/44—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing ionic groups cationic
  • D21H17/45—Nitrogen-containing groups
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
  • D21H21/06—Paper forming aids
  • D21H21/10—Retention agents or drainage improvers

Definitions

• 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.
• a drainage improver has been added.
• 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.
• 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.
• 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.
• 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.
• 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.
• a monomer called a dispersion polymerization method is added to a papermaking pulp in a papermaking process.
• 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.
• a dispersant composed of a polymer electrolyte soluble in the salt aqueous solution.
• 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.
• 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.
• 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%.
• 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.
• 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.
• 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.
• 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.
• 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.
• 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.
• 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.
• 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.
• 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.
• 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.
• 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).
• 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.
• 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.
• 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.
• 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.
• acrylic or methacrylic anion monomer examples 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.
• preferred water-soluble anionic vinyl monomers are acrylic acid and methacrylic acid, most preferably acrylic acid.
• 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.
• 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.
• 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.
• a preferable range thereof is a water-soluble cationic compound represented by the above formula (1).
• 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.
• 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.
• 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.
• 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.
• 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.
• 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.
• the cationic group has at least twice the gram equivalent value of the anionic group.
• 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).
• amphoteric water-soluble polymer examples 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.
• 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.
• 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.
• 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.
• 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.
• 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.
• dispersant examples 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
• 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.
• 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.
• 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.
• 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.
• the polymerization temperature there is no particular limitation on the polymerization temperature as long as the polymerization initiator acts properly at the selected temperature.
• 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.
• 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.
• 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.
• 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.
• 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.
• 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.
• 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.
• 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.
• 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.
• 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.
• 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.
• 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.
• 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. .
• 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.
• a ⁇ c acrylic acid
• a Am Acrylamide (Example of preparation of acrylic acid (co) polymer)
• a polymerization initiator 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.
• Sample G 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)
• the yield was measured by a brit-type dynamic jar tester. The test was performed in the following procedure.
• 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.
• the total yield and the filler yield are determined by the following equations.
• Example 1 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]
• the ionic polymer dispersions (A) to (F) were added to papermaking pulp to conduct a drainage test.
• 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.
• 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.

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