JP4517662B2 - Paper and paperboard manufacturing method - Google Patents

Description

  The present invention relates to a method for producing paper and paperboard, and in particular, a water-soluble cationic polymer polymer is added to a paper material, and then a water-soluble amphoteric polymer polymer is added, followed by addition of anionic organic polymer fine particles. As a result, even with a paper with a lot of anionic trash, while suppressing deterioration of the texture, drastically improved drainage and yield, and solved secondary obstacles such as poor workability and scale generation. The present invention relates to a method of manufacturing paper and paperboard.

  In recent years, in the manufacture of paper and paperboard, an increase in the utilization rate of waste paper, an improvement in the blending ratio of broke pulp, the closure of the system, etc., and the increase in anionic impurities in the raw material, so-called anion trash, Not only the occurrence of pitch and defects, but also a drop in productivity such as paper breaks and production speed reduction.

  In response to these problems, Japanese Patent No. 3218557 describes a method of improving the yield by adding an amphoteric polymer of dispersion, colloidal silica, and bentonite to the stock before dehydration. EP 235893 (corresponding to JP 62-191598 A) also describes a first synthetic cationic polymer prior to a specific shearing step in order to improve drainage, retention, drying and formation properties. And a method of adding bentonite after the shearing step is disclosed and is commercially available.

  However, these methods have not been able to obtain a satisfactory yield effect, particularly a satisfactory filler yield. Increasing the amount of filler added improves yield, but in this case there is a problem that the texture of the product decreases. Furthermore, when bentonite is used, it takes time for dissolution, and when using colloidal silica, the concentration of active ingredients is low, which increases transportation costs. There is a problem that the quality deteriorates.

  In Japanese Patent Publication No. 5-29719 (Patent No. 21287702), a cationic polymer having a molecular weight lower than that of the main polymer is added before the main cationic polymer, and finally an anionic inorganic substance is added. A method for improving drainage is described. However, this method has a problem that the yield, in particular, the improvement of the yield effect of the filler is not remarkable.

  Furthermore, Japanese Patent No. 2948358 discloses a yield improving method in which a cationic polymer and anionic polymer fine particles are contained in a paper stock. However, this method has a problem that the yield effect is remarkably lowered particularly when there are many anionic impurities in the stock, so-called anion trash.

  In addition, the applicant of the present invention has first described a first step of adding a water-soluble cationic polymer subpolymer to a paper stock and a paper for the first step as a method for producing paper and paperboard to solve the above-mentioned conventional problems. A second step of adding the water-soluble cationic polymer main polymer to the material through at least one shearing step, and a second step of adding the anionic organic polymer fine particles to the stock of the second step through at least one shearing step. A paper and paperboard manufacturing method has been proposed that has three steps and a fourth step in which the stock of the third step is dehydrated to form a sheet and then dried (Japanese Patent Application No. 2003-285953, hereinafter referred to as “prior application”). .)

According to the method of this prior application, a water-soluble cationic polymer subpolymer (cationic subpolymer) is added as a cationic polymer for patch formation, and then a water-soluble cationic polymer main polymer (cationic main polymer) is added. After that, the anionic organic polymer fine particles are added to sufficiently secure the bonding portion between the cationic polymer and the anionic organic polymer fine particles, and the strong interaction between the cationic polymer and the anionic organic polymer fine particles is ensured. Not only can the effect be obtained, the pitch can be reduced, the defects can be reduced, the texture can be maintained, the drainage and the yield can be improved, and the productivity can be improved such as the reduction of paper breaks and the increase in production speed. Therefore, further improvement of the effect is desired.
Japanese Patent No. 3218557 EP235893 Japanese Patent Publication No. 5-29719 Japanese Patent No. 2948358 Japanese Patent Application No. 2003-285953

  The present invention responds to the recent improvement in the utilization rate of waste paper, the improvement in the blending ratio of broke pulp, and the close-up of the system, etc. Even with a stock with a lot of anionic trash, the pitch can be suppressed and defects can be reduced. It is another object of the present invention to provide a method for producing paper and paperboard that does not break down the texture, improves drainage and yield, and improves productivity such as reducing paper breaks and increasing production speed.

  The object of the present invention is to provide a paper and paperboard production method that is superior to the above-mentioned prior application.

  The method for producing paper and board according to the present invention comprises a first step of adding a water-soluble cationic polymer to a stock and a water-soluble amphoteric polymer through at least one shearing step in the stock of the first step. A second step of adding the anionic organic polymer fine particles to the stock of the second step through at least one shearing step, and dehydrating the stock of the third step to form a sheet And a fourth step of drying.

  The problem in the prior art in which cationic polymers and amphoteric polymers are combined with anionic inorganic fine particles represented by bentonite and colloidal silica is that the cohesive force between the cationic polymer and amphoteric polymer and anionic inorganic fine particles is not sufficient. In particular, when the anion trash component in the stock increases, the cohesive force further decreases, and a sufficient yield effect cannot be obtained.

  In the present invention, a water-soluble cationic polymer (hereinafter sometimes referred to as “cationic polymer”) is added as a patch-forming cationic polymer, and then a water-soluble amphoteric polymer (hereinafter “amphoteric polymer”). After the addition of anionic organic polymer fine particles, a sufficient bond between the amphoteric polymer and the anionic organic polymer fine particles is secured, and the amphoteric polymer and the anionic organic polymer fine particles are secured. In addition to obtaining strong interaction with molecular fine particles, suppressing pitch and reducing defects, it does not break down the ground, improves drainage and yield, reduces paper breakage, and increases production speed. Improve. Here, the formation of the patch means a phenomenon in which the cationic polymer is locally adsorbed on a solid anionic surface such as pulp fiber or filler, and the site becomes cationic.

  Thus, the details of the mechanism of action of the paper and paperboard production method of the present invention in which the cationic polymer, the amphoteric polymer, and the anionic organic polymer fine particles are sequentially added have not yet been fully elucidated. Presumed.

The addition of the cationic polymer for forming the patch has the following two functions (1) and (2).
(1) By partially neutralizing the anionic trash with the cationic polymer, the cation of the amphoteric polymer added next is reduced to be consumed by the anionic trash, and the amphoteric polymer is more likely to act.
(2) A cationic polymer for patch formation is added to the stock, and pulp fibers (including any solids present in the stock such as fillers, hereinafter may be referred to as “fibers”). They are once aggregated, but after being dispersed by the shearing force in the paper preparation process, a cationic patch is formed on the surface of the fiber, etc. Due to the repulsion, it takes a shape such as a tail or a loop, and makes it difficult to become flat, thereby enhancing the binding property with the anionic organic polymer fine particles.
The added amphoteric polymer forms an ion complex with the amphoteric polymer itself, maximizes the original molecule, and works more effectively on the aggregating action.

  The operation (2) will be further described with reference to FIGS. When the amphoteric polymer 2 is added directly to the fiber 1 or the like as in the prior art, the amphoteric polymer 2 adsorbed in a tail shape (2B) or loop shape (2A) on the fiber etc. 1 as shown in FIG. Changes over time as shown in FIG. 2B. This flat amphoteric polymer 2C cannot sufficiently secure the bonding portion with the anionic fine particles, and as a result, the interaction cannot be sufficiently obtained and the aggregation effect becomes insufficient.

  On the other hand, in the present invention, first, a cationic polymer for patch formation is added, and the cationic polymer 3 is adsorbed on the surface of the fiber 1 or the like as shown in FIG. In addition, as shown in FIG. 1B, the apparent molecules are enlarged (4K) by forming an ion complex between the amphoteric polymers 4 and 4. When such an amphoteric polymer 4 is added after the addition of the cationic polymer, the cationic group of the amphoteric polymer 4 is repelled by the cationic polymer 3, and the anionic group of the amphoteric polymer 4 is repelled by the anion surface of the fiber. Adsorption is performed at locations between anions and cations, as shown in FIGS. 1 (c) and 1 (d), adsorbed to the fiber 1 or the like in the form of tails (4KB) or loops (4KA). Even on the adsorbed cationic polymer 3, it is adsorbed in the form of tail (4KB) or loop (4A) and hardly forms a flat shape. Furthermore, due to the formation of an ion complex between the amphoteric polymers 4 and 4, the apparent molecules are enlarged, and tail-like and loop-like adsorptions are also greatly formed. As described above, the amphoteric polymer 4 adsorbed to the fiber 1 or the like in a tail shape (4 KB) or a loop shape (4KA) has many bonding portions with the anionic organic polymer fine particles, and has a strong interaction with the anionic organic polymer fine particles. As a result, a significantly higher yield effect can be obtained with a remarkably higher agglomeration effect than the conventional method.

In the present invention, since anionic organic polymer fine particles are used as the anionic fine particles, the following excellent effects can be obtained as compared with the case of using anionic inorganic fine particles.
(1) The anion degree can be designed freely.
(2) A dissociation sensitive group can be added according to the purpose.
(3) Since the part where the particles swell and react is widened, the effect is superior to that of inorganic particles.

  According to the paper and paperboard production method of the present invention, a strong interaction between the cationic polymer and the anionic organic polymer fine particles provides a good additive effect, and even in the case of a paper with a lot of anionic trash, the pitch can be reduced. In addition to suppressing and reducing defects, it is possible to improve productivity, such as reducing paper breaks and increasing production speed, as well as improving drainage and yield without destroying the texture.

  Embodiments of the paper and board manufacturing method of the present invention will be described in detail below.

  First, the cationic polymer, amphoteric polymer and anionic organic polymer fine particles used in the present invention will be described.

  Although there are no particular restrictions on the monomer component of the cationic polymer used in the present invention, in order to form a patch, the intrinsic viscosity in a 1N aqueous sodium nitrate solution (in the case of a polymer that causes precipitation in a 1N aqueous sodium nitrate solution) The intrinsic viscosity in 1N saline is preferably 15 dl / g or less, and the cationic equivalent has a physical property of 0.5 to 11 meq / g. When the intrinsic viscosity in a 1N sodium nitrate aqueous solution (in the case of a polymer that precipitates in a 1N sodium nitrate aqueous solution, the intrinsic viscosity in a 1N saline solution) exceeds 15 dl / g, the molecular weight is too large and weak against shearing. When the cationic equivalent is less than 0.5 meq / g, it is difficult to form a patch, and when it exceeds 11 meq / g, it reacts strongly and tends to form aggregated foreign matter. For this reason, from the viewpoint of securing strength against shearing, in order to obtain an appropriate molecular weight, the intrinsic viscosity in a 1N aqueous sodium nitrate solution (in the case of a polymer that precipitates in a 1N aqueous sodium nitrate solution is 1 N). The intrinsic viscosity in saline is preferably 15 dl / g or less. Further, from the viewpoint of effectively forming a patch, the cationic equivalent is preferably 0.5 meq / g or more, and from the viewpoint of suppressing the formation of aggregated foreign matters, the cationic equivalent is 11 meq / g or less. It is desirable. The more preferable intrinsic viscosity is 0.1 to 13 dl / g, and the cation equivalent is 1 to 10 meq / g.

  Specific examples of desirable cationic polymers include, for example, polyethyleneimine or a condensation product of polyethyleneamine and epichlorohydrin, a homopolymer of dicyandiamide, or a homopolymer of dimethyldiallylammonium, (meth) acryloyloxyethyltrimethylammonium chloride, Or the copolymer of these and acrylamide is mentioned. These cationic polymers may be used alone or in combination of two or more. Among these, a polymer of dimethyldiallylammonium or a copolymer with acrylamide, a polymer of (meth) acryloyloxyethyltrimethylammonium chloride or a copolymer with acrylamide is desirable, and the cationic monomer content is 10 to 10. 100 mol% and acrylamide content of 0-90 mol% are preferable.

  There are no particular restrictions on the monomer constituents of the amphoteric polymer used in the present invention, but specific examples of desirable amphoteric polymers include 0.5 to 90 mol% of cationic monomer units represented by the following general formula (1), (meta ) One or two or more anionic monomer units selected from the group consisting of acrylic acid, itaconic acid, acrylamide-2-methylpropanesulfonic acid and salts thereof, 0.2 to 90 mol%, acrylamide units 1 to 99. 3 mol%, the intrinsic viscosity in a 1N aqueous sodium nitrate solution (pH 3) is 0.1 dl / g or more, the cationic equivalent is 0.1 to 5 meq / g, and the anionic equivalent is 0.01 to 10 meq / The thing which has the physical property of g is mentioned.

（但し、ＡはＯ又はＮＨを表し、ＢはＣ_２Ｈ_４、Ｃ_３Ｈ_６又はＣＨ_２ＣＨＯＨＣＨ_２を表し、Ｒ^１はＨ、メチル基、エチル基、ベンジル基又は３−クロロ−２−ヒドロキシプロピル基を表し、Ｒ^２，Ｒ^３，Ｒ^４は各々独立に、Ｈ、炭素数１〜３のアルキル基、アルコキシル基、或いはベンジル基を表し、Ｘ⁻はアニオンを表す。）

(However, A represents O or NH, B represents C ₂ H ₄ , C ₃ H ₆ or CH ₂ CHOHCH ₂ , and R ¹ represents H, a methyl group, an ethyl group, a benzyl group, or 3-chloro-2- A hydroxypropyl group, R ² , R ³ , and R ⁴ each independently represent H, an alkyl group having 1 to 3 carbon atoms, an alkoxyl group, or a benzyl group, and X ⁻ represents an anion.)

  When the intrinsic viscosity of this amphoteric polymer in an aqueous 1 N sodium nitrate solution (pH 3) is less than 0.1 dl / g, it is difficult to form loop-like or tail-like adsorption on the patch surface, and the cationic equivalent is 0.1 meq / g. If it is less than 5, it is difficult to obtain sufficient adsorption. Further, if the anionic equivalent is less than 0.01 meq / g, it is difficult to obtain sufficient adsorption, and if it exceeds 10 meq / g, it reacts strongly to easily generate aggregated foreign matters. For this reason, the intrinsic viscosity of this amphoteric polymer in a 1N aqueous sodium nitrate solution (pH 3) is 0.1 dl / g or more in order to sufficiently form loop-shaped or tail-shaped adsorption on the patch surface. Similarly, in order to obtain sufficient adsorption, the amphoteric polymer desirably has a cationic equivalent of 0.1 meq / g or more. From the viewpoint of suppressing the formation of aggregated foreign substances, the cationic equivalent is 5 meq / g. g or less is desirable. Also, the anionic equivalent of the amphoteric polymer is desirably 0.01 meq / g or more in order to obtain sufficient adsorption, and from the viewpoint of suppressing the formation of aggregated foreign matters, it may be 10 meq / g or less. desirable. The more preferable intrinsic viscosity is 1 to 25 dl / g, the cationic equivalent is 0.5 to 4 meq / g, and the anionic equivalent is 0.05 to 9 meq / g.

  The anionic organic polymer fine particles used in the present invention are preferably the fine particles of A described in claim 2 of Japanese Patent No. 2948358, and when cross-bonded, the diameter is less than about 750 nm and non-cross-linked. And is insoluble in water, the diameter is smaller than about 60 nm, and the anionic equivalent of the fine particles is 0.1 meq / g or more.

  Examples of such anionic organic polymer fine particles include a microemulsion copolymer in which acrylic acid and acrylamide are cross-linked with N, N′-methylbisacrylamide.

  The anionic organic polymer fine particle is a composition comprising a mixture of an ionic polymer fine particle and a high molecular weight ionic polymer or ionic polysaccharide as described in claim 2 of Japanese Patent No. 2948358. It may be.

  In the present invention, a cationic polymer is first added to the stock. Since the cationic polymer is added for patch formation, it is important that the cationic polymer is sufficiently adsorbed on the surface of the fiber or the like. For this purpose, it is desirable that the cationic polymer is added before the fan pump in which the white water and the paper are mixed. The addition rate of the cationic polymer is preferably 0.002 to 0.5% by weight, more preferably 0.005 to 0.2% by weight, based on the dry paper stock.

  After the cationic polymer is added to form the patch, the amphoteric polymer is added. The amphoteric polymer is added after at least one shearing step after the cationic polymer is added. Preferably, the white water and the paper stock are added after being mixed. For example, it is added after the fan pump and the most desirable addition location is just before the machine screen. A preferred addition ratio of the amphoteric polymer is 0.002 to 0.5% by weight, more preferably 0.005 to 0.1% by weight, based on the dry paper stock.

  After the addition of the amphoteric polymer, anionic organic polymer fine particles are added. The anionic organic polymer fine particles are added after at least one shearing step after the amphoteric polymer is added. For example, when the amphoteric polymer is added before the second fan pump, the anionic organic polymer fine particles are added after the second fan pump, and when the amphoteric polymer is added before the machine screen, the anionic organic polymer particles are added. The fine polymer particles are desirably added after the machine screen. The preferred addition rate of the anionic organic polymer fine particles is 0.002 to 0.5% by weight, more preferably 0.005 to 0.1% by weight, based on the dry paper.

  In order to obtain a sufficient addition effect for any of the cationic polymer, the amphoteric polymer and the anionic organic polymer fine particles, the addition rate is preferably set to be equal to or higher than the lower limit of the addition rate, and the texture is good. In order to achieve this, it is desirable to make it not more than the upper limit of the addition rate.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.

  In addition, the additive used in the following Examples and Comparative Examples is as follows. In the following, “part” means “part by weight”.

(1) Additives used in Examples and Comparative Examples

(2) Details of Anionic Organic Polymer Fine Particle “C” Used in Examples: Acrylic acid / acrylamide / N, N′-methylenebisacrylamide copolymer: N, N′-methylenebisacrylamide (MBAAm) at 349 ppm A cross-linked microemulsion copolymer of 30 mol% sodium acrylate (AA) and 70 mol% acrylamide (AAm) with a particle size of 130 nm.

  The above-mentioned anionic organic polymer fine particles were produced by the following method.

  Sequentially, 147 parts of acrylic acid, 200 parts of deionized water, 144 parts of 56.5% by weight sodium hydroxide, 343.2 parts of acrylamide crystals, 0.3 part of 10% by weight diethylenetriaminepentaacetic acid pentasodium, and 39. An aqueous phase was prepared by mixing 0 parts and 1.5 parts of 0.52 wt% copper sulfate pentahydrate. To 110 parts of the resulting aqueous phase solution was added 0.25 parts of 1 wt% t-butyl hydroperoxide and 3.50 parts of 0.61 wt% N, N'-methylenebisacrylamide. Next, 120 parts of the aqueous phase was mixed with an oil phase containing 77.8 parts of paraffin oil, 3.6 parts of fatty acid sorbitan (containing oleic acid) and 21.4 parts of polyoxyethylene sorbitol hexaoleate.

The resulting clear microemulsion was degassed with nitrogen for 20 minutes. Polymerization was initiated using gaseous SO ₂ , the exotherm was brought to 40 ° C. and controlled to 40 ° C. using ice water. The ice water was removed when no further cooling was required. Thereafter, nitrogen was passed through for 1 hour to obtain a polymer.

(3) Anionic inorganic fine particles used in Comparative Examples Colloidal silica: Alkaline-stabilized commercial colloidal silica having an average particle size of 5 nm (trade name “BMA” manufactured by Eka Chemicals)
Bentonite: A commercially available anionic swelling bentonite made of sepiolite, attapulgite or montmorillonite (Ciba Specialty Chemicals, trade name “Orgaoosorb O”)

Moreover, the following measuring apparatus was used for the yield rate measurement of a filler, and the measurement of a formation index.
Yield rate of filler: Made by Mutech, drainage yield tester “DFS (Dynamic Filtration System)”
Ground index: “3-D Sheet Analyzer” manufactured by M / K System Inc.

Example 1 and Comparative Examples 1 to 15: Examples of Neutral Medium Paper From a certain paper mill, pulp samples of LBKP (hardwood bleached kraft pulp), NBKP (softwood bleached kraft pulp), DIP (waste paper pulp), and actual machine White water was collected, and the above pulp samples were weighed so as to be LBKP 40%, NBKP 20%, DIP 40% (all dry weight%, the same applies hereinafter), and then the following two methods (i) and (ii) were used. Cationic polymer (patch-forming polymer) was added (however, in Comparative Examples 1 to 3, no cationic polymer was added).
(i) Cationic polymer was added to the DIP sample, immediately sheared with a stirrer at 800 rpm for 40 seconds to break the floc, and then mixed with each of the LBKP and NBKP pulp samples (the cationic polymer was added to the DIP chest. Is assumed to be added).
(ii) Cationic polymer was added to the stock containing 3 types of pulp samples in the above ratio, and immediately afterwards shearing was performed with a stirrer at 800 rpm for 40 seconds to break the floc (the mixing chest was cationic Assuming polymer is added).

  Next, white water is added to the stock obtained by any of the addition methods, and after adjusting so that the concentration per dry weight of the mixed pulp sample is 0.8% by weight, the mixture is again put into the stirrer, Shear was applied at 800 rpm for 40 seconds to break the floc.

  Each stock (A) thus obtained was put into a yield tester “DFS”, and a sulfuric acid band (aluminum sulfate) was added to 1.5% by weight of dry pulp and cationized starch (“Cato-” manufactured by NSC). 3212 ") with respect to dry pulp 0.5% by weight, sizing agent (" NT-87 "manufactured by Arakawa Chemical Industries, Ltd.) 0.25% by weight with respect to dry pulp, calcium carbonate (" TP-12L "manufactured by Okutama Kogyo Co., Ltd.) Were added in the order of 10% by weight of dry pulp and an amphoteric polymer (the second cationic polymer in Comparative Examples 1 to 15), followed by the addition of anionic fine particles, and the filtrate (B) was collected (DFS). (The shearing condition by the testing machine was applied by applying stirring under standard conditions.)

  Table 2 shows the types and addition amounts of the cationic polymer, amphoteric polymer, second cationic polymer and anionic fine particles used in each example.

The concentration of the filler in the collected filtrate (the filler content was in accordance with the ash content measuring method “ISO1762-1974”) was measured, and the yield rate of the filler was calculated according to the following formula.
Yield rate of filler = [1-ash content of filtrate (B) / ash content of paper material (A)] × 100%

  A handmade sheet was prepared using the paper stock prepared by the same ratio and method as described above, and the texture index was measured.

  Table 2 shows the results of the test using the yield tester and the results of measuring the texture index of the handsheets. As is clear from Table 2, in Example 1, the filler yield was improved and the texture was better than Comparative Examples 1-15.

Example 2 and Comparative Examples 16 to 30: Examples of neutral fine paper LBKP, NBKP, coat broke pulp samples and actual white water were collected from the same paper mill as in Example 1, LBKP 60%, NBKP 20%, coat After the pulp sample was weighed so that the broke was 20%, a cationic polymer (patch-forming polymer) was added by the following three methods (iii) or (iv) or a combination (v) of these. (However, in Comparative Examples 16 to 18, no cationic polymer was added).
(iii) Cationic polymer was added to the coated broke sample, immediately sheared with a stirrer at 800 rpm for 40 seconds to break the floc, and then mixed with each of the LBKP and NBKP pulp samples (which was cationic in the DIP chest) Assuming polymer is added).
(iv) A cationic polymer was added to the stock containing the three types of pulp samples in the above ratio, and immediately sheared with a stirrer at 800 rpm for 40 seconds to break the floc (the cationic polymer in the mixing chest). Is assumed to be added).
(v) The above (iii) and (iv) were combined, and the cationic polymer was added by 50% of the total amount added. That is, after adding a cationic polymer to the coat broke in advance and applying shear, three kinds of pulp samples were blended, and then the cationic polymer was added again to apply shear.

  Next, after adding white water to the paper stock of any addition method and adjusting the concentration of the mixed pulp sample per dry weight to 0.8% by weight, the yield tester “DFS” And 1.5% by weight of sulfuric acid band with respect to dry pulp and 0.5% by weight of cationized starch (Cato-3212) with respect to dry pulp, and then sizing agent (NT-87) with respect to 0.1% by weight of dry pulp. 25% by weight, calcium carbonate (TP-121) is added in the order of 10% by weight of dry pulp and amphoteric polymer (however, the second cationic polymer in Comparative Examples 16 to 30), followed by the addition of anionic fine particles The filtrate was collected (DFS was set using the recommended method of Mutek, Inc. Shearing by this tester was applied by applying stirring under standard conditions).

  Table 3 shows the types and addition amounts of the cationic polymer, amphoteric polymer, second cationic polymer and anionic fine particles used in each example.

  For the collected filtrate, the yield rate of the filler was determined in the same manner as in Example 1, and the texture index of the handsheet was measured in the same manner as in Example 1. The results are shown in Table 3. As is apparent from Table 3, in Example 2, the filler yield was improved and the texture was better than in Comparative Examples 16-30.

  According to the paper and paperboard manufacturing method of the present invention, even a paper with a lot of anionic trash not only suppresses the pitch and reduces defects, but also does not break the texture and improves the drainage and yield. At the same time, it is possible to improve productivity by reducing the number of paper breaks and speeding up production. Therefore, the production of paper and paperboard corresponding to the recent improvement in the utilization rate of used paper, the improvement in the blending ratio of broke pulp, the closure of the system, etc. Can be implemented.

It is a schematic diagram explaining the action mechanism of the aggregation effect by this invention. It is a schematic diagram explaining the cause of the cohesion fall in a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fiber etc. 2 Amphoteric polymer 2A Loop-shaped amphoteric polymer 2B Tail-shaped amphoteric polymer 2C Flat-shaped amphoteric polymer 3 Cationic polymer (patch)
4 Amphoteric polymer 4K Giant amphoteric polymer 4KA Giant amphoteric polymer in loop form 4KB Giant amphoteric polymer in tail form

Claims (4)

A first step of adding a water-soluble cationic polymer to the stock;
A second step of adding a water-soluble amphoteric polymer to the stock of the first step via at least one shearing step;
A third step of adding the anionic organic polymer fine particles to the stock of the second step through at least one shearing step;
A paper and paperboard manufacturing method comprising: a fourth step of dehydrating the paper stock of the third step to form a sheet and then drying.   The water-soluble cationic polymer has an intrinsic viscosity in a 1N sodium nitrate aqueous solution (in the case of a polymer that precipitates in a 1N aqueous sodium nitrate solution, the intrinsic viscosity in 1N saline) is 15 dl / g or less, and the cationic equivalent 2. The method for producing paper and paperboard according to claim 1, wherein the paper has a physical property of 0.5 to 11 meq / g.   When the anionic organic polymer fine particles are smaller than about 750 nm in diameter when cross-linked, and smaller than about 60 nm in diameter when non-cross-linked and water-insoluble, the anionic equivalent of the fine particles is 0.1 meq / The method for producing paper and paperboard according to claim 1 or 2, wherein the production method is g or more. The water-soluble amphoteric polymer is a cationic monomer unit of 0.5 to 90 mol% represented by the following general formula (1),
0.2 to 90 mol% of one or more anionic monomer units selected from the group consisting of (meth) acrylic acid, itaconic acid, acrylamide-2-methylpropanesulfonic acid and salts thereof,
Acrylamide units 1-99.3 mol%
Have
The intrinsic viscosity in a 1N aqueous sodium nitrate solution (pH 3) is 0.1 dl / g or more, the cationic equivalent is 0.1 to 5 meq / g, and the anionic equivalent is 0.01 to 10 meq / g. The method for producing paper and paperboard according to any one of claims 1 to 3, wherein:

(However, A represents O or NH, B represents C ₂ H ₄ , C ₃ H ₆ or CH ₂ CHOHCH ₂ , and R ¹ represents H, a methyl group, an ethyl group, a benzyl group, or 3-chloro-2- A hydroxypropyl group, R ² , R ³ , and R ⁴ each independently represent H, an alkyl group having 1 to 3 carbon atoms, an alkoxyl group, or a benzyl group, and X ⁻ represents an anion.)

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