JP2001254290A - Paper making method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anionic material producing floc hard to be affected by a subtle adjustment of the addition amount of a cationic polymer or shearing forces affecting on the paper making process and having a proper strength preventing collapse of texture of papers after paper making comparing to a conventional colloidal silica or bentonite, in improving yielding percentage on wires of paper making process by combining a cationic or an amphoteric polymer with the anionic material. SOLUTION: This paper making method comprises adding one or more of a cationic aqueous polymer, an amphoteric aqueous polymer, a cationic starch or an amphoteric starch to a paper making stock before paper making, and then adding an anionic polymer comprising a dispersion obtained by (co) polymerizing aqueous monomer including (meth)acrylic acid in an aqueous solution of a salt in the presence of a polymeric dispersant soluble in the salt solution.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a papermaking method, and more particularly, to a method of adding a cationic and / or amphoteric polymer substance to a papermaking raw material dispersion and mixing the resulting mixture with a specific anionic water-soluble polymer. The present invention relates to a papermaking method capable of achieving a high yield rate by adding a polymer without breaking the formation after papermaking.

[0002]

2. Description of the Related Art In the papermaking industry, improving the yield rate on a wire in a papermaking process is required to reduce drainage load,
This has important implications such as a reduction in manufacturing costs and efficient recycling of the filling. Therefore, various yield improvement methods have been proposed to date. For example, a method of adding and mixing a cationic or amphoteric polymer and then adding and mixing colloidal silica to form a paper (JP-A-3-27676)
JP-A-60-18) A method in which 25-60 mol% of an anionic polymer is added, and then a Huffman reactant of cationic starch or polyacrylamide is added.
No. 5900), a method of adding and mixing a cationic polymer and then adding bentonite (Japanese Patent Application Laid-Open No. 62-191).
598), a method of adding and mixing a high-molecular-weight cationic polymer, and then adding a medium-molecular-weight anionic polymer (Japanese Patent Laid-Open No. 4-245998); a method of adding and mixing a cationic polymer; For example, a method of adding a mixture of a reactive polymer and bentonite (JP-A-64-61588). Of these methods, the method of using both a cationic polymer and an anionic polymer is particularly preferable because an anionic polymer is usually added after the cationic polymer is added. Many.
For this reason, the distance to the machine is short, the dispersion of the anionic polymer is inevitably inhomogeneous, and there is always a danger such as collapse of the formation after papermaking. In this regard, the method of adding bentonite or colloidal silica as an anionic substance is good in terms of dispersion, but insufficient in terms of cohesive strength, and the floc strength generated in combination with a cationic polymer is slightly too weak. Tend. Therefore, there is a long-awaited need to study an optimal anionic substance to be combined with a cationic polymer to be used in combination.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to develop a formulation which improves the yield on wires by combining with cationic and / or amphoteric polymeric substances. In other words, compared to existing colloidal silica and bentonite, the amount of the cationic polymer used in combination is delicately adjusted, and it is less affected by the various shearing forces involved in the papermaking process, and moreover, it does not cause the paper to collapse after papermaking. The purpose of the present invention is to investigate an anionic substance which generates floc having a high strength.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above problems, an anionic water-soluble polymer composed of one or more cationic or amphoteric polymer substances and a polymer dispersion liquid has been obtained. By combining
It was found that the yield was improved, and the present invention was reached. That is, the invention of claim 1 of the present invention relates to a method for preparing a cationic water-soluble polymer, an amphoteric water-soluble polymer, a cationic starch or an amphoteric starch in a papermaking raw material before papermaking. After the addition and mixing of one or more of (meth)
A water-soluble monomer containing acrylic acid is added to a salt aqueous solution, and in the presence of a polymer dispersant soluble in the salt aqueous solution, an anionic water-soluble polymer composed of a dispersion produced by a dispersion polymerization method is added. And a papermaking method characterized by the following.

According to a second aspect of the present invention, a monomer composition containing 5 to 100 mol% of (meth) acrylic acid and 0 to 95 mol% of acrylamide is prepared in an aqueous salt solution by using an anionic water-soluble polymer. 2. The papermaking method according to claim 1, comprising polymer fine particles having a particle size of 100 [mu] m or less produced by a dispersion polymerization method in the presence of a polymer dispersant soluble in an aqueous salt solution.

A third aspect of the present invention is the papermaking method according to the first or second aspect, wherein the polymer dispersant is an anionic polymer.

The invention according to claim 4 is the papermaking method according to any one of claims 1 to 3, wherein the polymer dispersant is a cationic polymer.

According to a fifth aspect of the present invention, in the papermaking method according to any one of the first to fourth aspects, the ion equivalent of the polymer dispersant is from 1.50 meq / g to 15.0 meq / g. It is.

The invention according to claim 6 is characterized in that the molecular weight of the anionic water-soluble polymer comprising the dispersion produced by the dispersion polymerization method is 1,000,000 or more and 20,000,000 or less. 5. The papermaking method according to any one of 5.

The invention according to claim 7 is the papermaking method according to any one of claims 1 to 6, wherein the molecular weight of the cationic or amphoteric polymer is 1,000,000 or more and 20,000,000 or less. .

The invention according to claim 8 is the papermaking method according to any one of claims 1 to 7, wherein the cationic or amphoteric starch has a molecular weight of 50,000 to 5,000,000.

According to a ninth aspect of the present invention, the salt constituting the salt aqueous solution is a polyvalent anionic salt.
A papermaking method according to any one of claims 1 to 8.

The invention according to claim 10 is the invention wherein the papermaking pH is 6.0 to 6.0.
10. The papermaking method according to claim 1, wherein the papermaking method is 9.0.

[0014] The invention of claim 11 is a method for preparing a papermaking raw material before papermaking, wherein one or more of a cationic water-soluble polymer, an amphoteric water-soluble polymer, a cationic starch or an amphoteric starch is placed before the fan pump or in the screen. 11. An anionic water-soluble polymer comprising a dispersion prepared by a dispersion polymerization method, which is added at the entrance of a screen, and added at the entrance or exit of the screen. It is the papermaking method described.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The anionic water-soluble polymer comprising a dispersion produced by the dispersion polymerization method used in the present invention is obtained by mixing a water-soluble monomer containing (meth) acrylic acid with an aqueous salt solution. This is a polymer dispersion produced by a dispersion polymerization method in the presence of a dispersant comprising a polymer soluble in the salt aqueous solution. Examples of the acid monomer used include methacrylic acid, acrylic acid, and itaconic acid. Further, the dispersion liquid composed of the polymer fine particles may be a copolymer with another nonionic monomer. For example, (meth) acrylamide,
N, N-dimethylacrylamide, vinyl acetate, acrylonitrile, methyl acrylate, (meth) acrylic acid 2
-Hydroxyethyl, diacetone acrylamide, N-
Examples thereof include vinylpyrrolidone, N-vinylformamide, and N-vinylacetamide, and copolymerization with one or more of these acid monomers or nonionic monomers is possible. The most preferred combination is acrylic acid and acrylamide. The ratio of these acid monomers in the (co) polymer is 5-1.
00 mol%, preferably 10 to 100 mol%.

The polymer constituting the dispersion has a molecular weight of 1,000,000 to 20,000,000, preferably 500,000,000.
10,000 to 20 million. If it is less than 1,000,000, the cohesive strength is insufficient and the yield decreases, and if it is more than 20,000,000, the cohesive strength is too high and the formation collapses after papermaking. In addition, the solution viscosity becomes too high, dispersibility deteriorates, and handling of the aqueous solution also deteriorates.

In preparing the dispersion comprising the polymer fine particles used in the present invention, any of anionic and cationic polymers can be used as a dispersant. As the anionic polymer, a homopolymer of an anionic monomer or a copolymer of an anionic monomer and a nonionic monomer can be used. Examples of non-ionic monomers include:
Acrylamide, N-vinylformamide, N-vinylacetamide, N-vinylpyrrolidone, N, N-dimethylacrylamide, acrylonitrile, diacetoneacrylamide, 2-hydroxyethyl (meth) acrylate and the like. The anionic monomer is acrylamide 2-methylpropanesulfonic acid, styrenesulfonic acid, (meth) acrylic acid, etc., and the most preferable combination is acrylamide 2-methylpropanesulfonic acid (salt) and methacrylic acid (salt). And a copolymer of
Examples of the cationic polymer include homopolymers such as (meth) acryloyloxyethyltrimethylammonium chloride, dimethyldiallylammonium chloride, and (meth) acryloylaminopropyltrimethylammonium chloride; It is a copolymer with a nonionic monomer. Preferably used are homopolymers of acryloyloxyethyltrimethylammonium chloride.

The salts used in the polymerization include salts of alkali metal ions such as sodium and potassium or ammonium ions with halide ions, sulfate ions, nitrate ions and phosphate ions. Are more preferred. The concentration of the salt solution is not less than 5% by weight and not more than the saturation concentration.

The acid in the polymer constituting the dispersion of the polymer fine particles used in the present invention is obtained by neutralizing 10 to 20 mol% of (meth) acrylic acid used as a raw material.
It is mixed with a nonionic monomer or the like and polymerized with stirring. Usually, the polymerization conditions are appropriately determined depending on the monomers used and the molar ratio of copolymerization, and the temperature is in the range of 0 to 100 ° C.
For the initiation of polymerization, a radical polymerization initiator is used. For example,
Redox systems such as ammonium or potassium peroxodisulfate and sodium bisulfite, or water-soluble azo initiators, such as 2,2-azobisamidinopropane dihydrochloride, 2,2-azobis [2- (5- Methyl-2-imidazolin-2-yl) propane] dihydrochloride, oil-soluble azobisisobutyronitrile, and peroxides such as lauryl peroxide. When an oil-soluble initiator is used, it is once dissolved in a water-miscible solvent and added to the polymerization solution.

The cationic water-soluble polymer or the amphoteric water-soluble polymer used in combination with the anionic water-soluble polymer is an acrylic cationic monomer, for example, dimethylaminoethyl (meth) acrylate or dimethylaminopropyl. A salt of an inorganic acid or an organic acid such as (meth) acrylamide, or a copolymer of acrylamide with a quaternary ammonium salt of methyl chloride or benzyl chloride. For example, as monomers, (meth) acryloyloxyethyltrimethylammonium chloride, (meth) acryloyloxy 2-hydroxypropyltrimethylammonium chloride, (meth) acryloylaminopropyltrimethylammonium chloride, (meth) acryloyloxyethyldimethylbenzyl Ammonium chloride, (meth) acryloyloxy 2-hydroxypropyldimethylbenzylammonium chloride, (meth) acryloylaminopropyldimethylbenzylammonium chloride, and the like. Copolymerization of these monomers with nonionic monomers It is united. Acrylamide is preferred as the monomer to be copolymerized. In addition, an amphoteric polymer can be synthesized and used by copolymerizing an anionic monomer such as (meth) acrylic acid. The mol% of the cationic monomer constituting the cationic group in these cationic polymers is 5 to 70 mol%
It is. In the case of an amphoteric polymer, the constituent mol% of the cationic monomer is 20 to 70 mol%. The constituent mol% of the anionic monomer is 5 to 30 mol%, preferably 10 to 20 mol%.

The molecular weight of these cationic water-soluble or amphoteric water-soluble polymers is from 1,000,000 to 20,000,000, preferably from 1,000,000 to 15,000,000. 100
If it is less than 10,000, the cohesive strength is insufficient and the yield decreases, and if it is more than 20,000,000, the cohesive strength is too high and the formation collapses after papermaking.
In addition, the solution viscosity becomes too high, and the dispersibility becomes poor.
The handling of the aqueous solution also becomes poor.

The cationic degree of the cationic starch used in the present invention is 0.5 to glucose units.
Mol% or more, 5 mol% or less, preferably 1 mol% or more,
5 mol% or less. At 0.5 mol% or more, the cationicity is too low, the interaction with the anionic water-soluble polymer composed of the dispersion used in combination is too weak, and cationic starch modified at 5 mol% or more is not commercially available, so it is practical. is not. Further, the degree of cationization of the amphoteric starch is 1 mol% or more and 5 mol% or less, and the degree of anionization is 0.5 mol%.
Not less than 2 mol%. When the degree of cationization is 1 mol% or less, the effect of the amphoteric polymer is not exhibited, and when it is 5 mol% or more, the cationicity becomes too high and the effect of the amphoteric polymer is not exhibited. The degree of anionization is less than 0.2 mol%, 2 mol%
This is because the effect of the amphoteric polymer is not exhibited in the above case as well.

The molecular weight of these cationic or amphoteric starches is 10,000 or more and about 5,000,000, and the natural starches are used as they are in cationic or amphoteric starch as compared with those obtained by oxidation or enzymatic treatment to reduce the molecular weight. It is preferable to use a modified one.

The anionic water-soluble polymer comprising a dispersion produced by the dispersion polymerization method used in the present invention was produced by an aqueous solution polymerization method, a water-in-oil emulsion polymerization method, or a water-in-oil dispersion polymerization method. The apparent viscosity when dissolved in water is very low as compared with the anionic polymer. For example, in the case of a copolymer containing sodium acrylate and acrylamide at a molar ratio of 30/70, the viscosity of an aqueous solution having a molecular weight of about 13,000,000 and 0.2% by weight is determined by an aqueous solution polymerization method and a water-in-oil emulsion polymerization method. In the polymer produced by the water-in-oil dispersion polymerization method, the pressure is 400 to 800 mPa · s, whereas the anionic water-soluble polymer composed of the dispersion liquid produced by the dispersion polymerization method used in the present invention is 20 to 100mPa ・
s. This is affected by inorganic salts coexisting during polymerization. Further, 10 to 20 of the monomers used during the polymerization are used.
One factor is that it only neutralizes mole%. However, these effects alone cannot be explained. It is presumed that this phenomenon is caused by polymerization while precipitating the polymer formed in the aqueous salt solution, but the detailed mechanism is still unknown. Therefore, the low apparent viscosity means that the dispersibility in the papermaking raw material is good, and even if it is added at a place closer to the machine such as a screen outlet, there is a risk of trouble due to uneven dispersion. It can be said that it is low.

The addition amount of the anionic water-soluble polymer comprising the above dispersion is 20 p
pm to 5000 ppm, preferably 50 ppm to
1000 ppm. The amount of the cationic or amphoteric polymer added is 20 ppm to 5000 ppm, preferably 50 ppm to 1000 ppm.
Further, the amount of the cationic or amphoteric starch added is from 500 ppm to 10000 ppm, preferably from 2000 ppm to 10000 ppm.

The place where the cationic or amphoteric polymer substance is added may be a fan pump inlet or a screen inlet where papermaking raw materials are diluted with white water. Further, as a place where the anionic water-soluble polymer composed of the dispersion is added, a screen entrance or a screen exit may be considered.

The papermaking pH applicable to the papermaking method for improving the yield of the present invention is applicable to acidic papermaking.
Excellent effect in neutral papermaking compared to other processing methods. Therefore, there is an advantage in the papermaking pH in the range of 6.0 to 9.0. The target paper products include high quality, medium quality, and core base paper.

[0028]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples. However, the present invention is not limited to the following Examples unless it exceeds the gist thereof.

(Synthesis Example 1) In a four-necked 500 ml separable flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet tube, 107.7 g of deionized water, 26.8 g of ammonium sulfate, 17.9 g of sodium sulfate, 60 acrylic acid: 32.7 g, 50% acrylamide: 90.3 g
Was added, and 16 mol% of acrylic acid was neutralized with 5.8 g of 30% by weight sodium hydroxide. 15. A 15% by weight methacrylic acid / acrylamide 2-methylpropanesulfonic acid = 3/7 (molar ratio, neutralizes 90 mol% of acid) copolymer aqueous solution (solution viscosity 42, 600 mPa · s)
9 g were added. Thereafter, nitrogen is introduced from a nitrogen introduction tube while stirring to remove dissolved oxygen. During this time, the internal temperature is adjusted to 30 ° C. by a constant temperature water bath. 30 minutes after nitrogen introduction,
0.6 g of a 0.1% by weight aqueous solution of 0.1% by weight of ammonium peroxodisulfate and ammonium hydrogen sulfite were added in this order to initiate polymerization. 3 after the start of polymerization
At the end of time, the same amount of the initiator was added,
After a further 6 hours, 3.0 g each was added and the reaction was completed in 15 hours. This prototype is referred to as prototype-1. The molar ratio of acrylic acid to acrylamide of this prototype-1 was 30: 7.
0 and the viscosity was 200 mPa · s. As a result of microscopic observation, it was found that the particles had a size of 5 to 35 μm. The molecular weight was measured in the same manner as in Synthesis Example-1. Table 1 shows the results.

(Synthesis Example 2) Acrylic acid was used in the same manner as in Synthesis Example 1 except that the polymer dispersant was changed to acryloyloxyethyltrimethylammonium chloride homopolymer (20% by weight, viscosity 8300 mPa · s, 25 ° C.). Prototype-2 having a molar ratio of acrylamide of 10:90 was synthesized. The viscosity of this prototype was 250 mPa · s. In addition, as a result of microscopic observation, it turned out that it is a particle of 10-30 micrometers.
The molecular weight was measured in the same manner as in Synthesis Example-1. Table 1 shows the results.

(Synthesis Example 3) Prototype-3 having a molar ratio of acrylic acid and acrylamide of 50:50 was synthesized in the same manner as in Synthesis Example 1. The viscosity of this prototype was 130 mPa · s.
As a result of microscopic observation, it was found that the particles had a size of 5 to 20 μm. The molecular weight was measured in the same manner as in Synthesis Example-1. Table 1 shows the results.

(Synthesis Example 4) Prototype-4 having a molar ratio of acrylic acid and acrylamide of 70:30 was synthesized in the same manner as in Synthesis Example 1. The viscosity of this prototype was 130 mPa · s.
As a result of microscopic observation, it was found that the particles had a size of 5 to 20 μm. The molecular weight was measured in the same manner as in Synthesis Example-1. Table 1 shows the results.

(Comparative Synthesis Example) After the aqueous solution polymerization method (Comparative Products 1-3), the water-in-oil emulsion polymerization method (Comparative Product-2), and the water-in-oil dispersion polymerization method, the polymer Each of the anionic polymers separated into powder products (Comparative Product-3) was synthesized. Acrylamide and acrylic acid were mol% as shown in Table 2, and 16% of acrylic acid was used in the same manner as in Synthesis Examples 1-4.
The mole% was neutralized and polymerized. The results are shown in Table 2.

[0034]

Examples 1 to 8 Papermaking raw materials for the production of high quality paper (mainly LBKP, pH 6.23, total ss content 2.37%,
(Ash content: 0.41%) was used as a sample, diluted with tap water to a pulp concentration of 0.9% by weight, and the yield was measured by a brit type dynamic ja tester. As an additive chemical,
Cationic starch, 0.5% by weight of papermaking raw material (the same applies hereinafter), light calcium carbonate, 20%, neutral rosin size, 0.5%, sulfate band 0.6%, cationic / amphoteric polymer in Table 2 C-1 and C-2, 0.02%, and Table 1
Anionic water-soluble polymer comprising the dispersion of the present invention 0.0
1% are added in this order at intervals of 15 seconds under the following test conditions, and the stirring is started. The pH after all the chemicals were added was 6.87. After 30 seconds, the white water was discharged for 10 seconds, the white water was collected for 30 seconds, and the total yield was measured under the following conditions. The stirring conditions were as follows:
r. p. m. , Wire 125P screen (equivalent to 200 mesh), total yield (SS concentration) is ADVANTE
C NO. It filtered after 2 and measured. After drying, the filter paper was incinerated at 600 ° C., and the ash content was measured to calculate the yield of calcium carbonate. Table 5 shows the results.

[0035]

Comparative Examples 1 to 12 Comparative examples 1 to 5 were used as anionic water-soluble polymers, and the yield was measured by a brit type dynamic jaw tester in the same manner as in Examples 1 to 8. In addition, as an anionic substance, a test in which 500 ppm of bentonite (organozove 0, manufactured by Kyowa Sangyo) and 200 ppm of colloidal silica (BMA-780, manufactured by Eka) were combined with C-1 was also performed. Table 5 shows the results.

From the results shown in Table 5, it can be seen that when the dispersions of the present invention were used, all of them achieved high total yield and ash yield. On the other hand, comparison 1
Comparative Examples 1-1 using No. 5 as an anionic water-soluble polymer
In the case of 0 or Comparative Examples 11 to 12 using bentonite or colloidal silica, it can be clearly seen that the total yield and the ash yield are lower than those of Examples 1 to 8.

[0037]

Embodiments 9 to 16 Raw paper raw materials (LBKP / DIP / T
MP = 10/60/30, pH 7.1, total ss 2.40
%, Ash content 0.30%), and the yield was measured by the same operation as in Examples 1 to 8 under the condition of neutral papermaking. As additive chemicals, cationic starch, 0.25% of papermaking raw material,
Talc 5.5%, neutral rosin size, 0.2%, sulfate band 0.5%, cationic / amphoteric polymers C-3 and C-4 in Table 3, 0.015%, and book in Table 1. 0.01% of the anionic water-soluble polymer comprising the inventive dispersion was added in this order. The pH after all chemicals were added was 7.15. The results are shown in Table 6.

[0038]

Comparative Examples 13 to 24 Table 3 as cation / amphoteric polymer
Using C-3 and C-4 of Comparative Examples 1 to 3 and Comparative Examples 1 to 5 in Table 2 as anionic water-soluble polymers, the yield was measured by a brit type dynamic jaw tester in the same manner as in Examples 9 to 16. . In addition, as anionic substances, bentonite (organozove 0, manufactured by Kyowa Sangyo) 500 ppm, colloidal silica (BMA-780, manufactured by Eka) 200 pp
m was combined with C-3, and the test was also performed at the same time. Table 6 shows the results.

From the results shown in Table 6, it can be seen that when the dispersions of the present invention were used, all of them achieved high total yield and high ash yield. On the other hand, comparison 1
Comparative Examples 13 to 15 using No. 5 as an anionic water-soluble polymer
22 or Comparative Examples 23 to 24 using bentonite or colloidal silica, the total yield and the ash yield are clearly lower than those of Examples 9 to 16.

[0040]

Examples 17 to 24 Raw materials for core paper for cardboard (p
H7.5, total ss2.56%, ash content 0.53%), and the yield was measured by the same operation as in Examples 1 to 8 under the condition of neutral papermaking. As additive chemicals, 0.010% of cationic / amphoteric polymers C-5 and C-6 shown in Table 3 and anionic water-soluble polymer consisting of the dispersion of the present invention shown in Table 1 were added.
005% were added in this order. The pH after the addition of all the chemicals was 7.52. The results are shown in Table 7.

[0041]

Comparative Examples 25-36 Table 3 as cation / amphoteric polymer
Using C-5 and C-6 of Comparative Examples 1 to 3 and Comparative Examples 1 to 5 in Table 2 as anionic water-soluble polymers, the yield was measured by a brit type dynamic jaw tester in the same manner as in Examples 17 to 24. . As an anionic substance, bentonite (organozove 0, manufactured by Kyowa Sangyo) 500 ppm, colloidal silica (BMA-780, manufactured by Eka) 200 p
pm was combined with C-3, and the test was also performed at the same time. Table 7 shows the results.

From the results shown in Table 7, it can be seen that when the dispersions of the present invention were used, a high total yield and a high ash yield were achieved in all cases. On the other hand, comparison 1
Comparative Example 25 using No. 5 as an anionic water-soluble polymer
In the case of No. 34 or Comparative Examples 35 to 36 using bentonite or colloidal silica, it can be seen that the total yield and the ash yield are clearly lower than those of Examples 17 to 24.

[0043]

Examples 25 to 32 Tests were carried out using papermaking raw materials (raw materials similar to those in Examples 1 to 8) for producing high quality paper. As an additive chemical, cationic / amphoteric starch CS-1 shown in Table 4
Alternatively, AMS-1 is 0.6%, light calcium carbonate,
15%, 0.15% of an alkyl ketene dimer as a neutral sizing agent, and 0.015% of an anionic water-soluble polymer composed of the dispersion of the present invention shown in Table 1 were added in this order.
The pH after all the chemicals were added was 8.41. Table 8 shows the results.

[0044]

Comparative Examples 37 to 48 Tests were conducted in the same manner as in Examples 25 to 32. Comparison 1 of Table 2 as an anionic water-soluble polymer
5 was used. As an anionic substance, bentonite (organozove 0, manufactured by Kyowa Sangyo) 500 ppm, colloidal silica (BMA-780, manufactured by Eka) 200 p
pm was combined with C-3, and the test was also performed at the same time. Table 8 shows the results.

From the results shown in Table 8, it can be seen that when the anionic water-soluble polymer comprising the dispersion of the present invention was used, a high total yield and a high ash yield were all achieved.
On the other hand, Comparative Examples 37 to 46 using Comparative Examples 1 to 5 as anionic water-soluble polymers, or Comparative Examples 47 to 48 using bentonite or colloidal silica, were clearly compared with Examples 25 to 32. Total yield and ash yield are low.

[0046]

[Table 1] Acrylic acid: mol%, acrylamide: mol%, dispersion viscosity: mPa · s solution viscosity: 0.2% by weight of pure polymer viscosity, mPa · s, molecular weight: 10,000 units

[0047]

[Table 2] Acrylic acid: mol%, acrylamide: mol%, solution viscosity: polymer pure matter 0.2% by weight viscosity, mPa · s,
Molecular weight: unit is 10,000

[0048]

[Table 3] Cationic / amphoteric polymer Molecular weight: unit: 10,000 DMQ: acryloyloxyethyltrimethylammonium chloride (mol%) DMC: methacryloyloxyethyltrimethylammonium chloride (mol%) DD: diallyldimethylammonium chloride (mol%) AAM: acrylamide, AAC: acrylic Acid (mol%)

[0049]

[Table 4] Cationic / amphoteric starch Degree of cationization: mol% based on glucose units Degree of anionization: mol% based on glucose units Molecular weight: unit is 10,000

[0050]

[Table 5] Total yield: unit is% Ash yield: unit is%

[0051]

[Table 6] Total yield: unit is% Ash yield: unit is%

[0052]

[Table 7] Total yield: unit is% Ash yield: unit is%

[0053]

[Table 8] Total yield: unit is% Ash yield: unit is%

Claims (11)

[Claims] 1. A method for adding one or more of a cationic water-soluble polymer, an amphoteric water-soluble polymer, a cationic starch or an amphoteric starch to a papermaking raw material before papermaking and mixing the resulting mixture, and then mixing (meth) acrylic acid A water-soluble monomer containing
A papermaking method comprising adding an anionic water-soluble polymer comprising a dispersion produced by a dispersion polymerization method in a salt aqueous solution in the presence of a polymer dispersant soluble in the salt aqueous solution. 2. An anionic water-soluble polymer comprising 5 to 100 mol% of (meth) acrylic acid and 0 to 9 of acrylamide.
It is characterized by comprising polymer fine particles having a particle diameter of 100 μm or less produced by a dispersion polymerization method in a salt aqueous solution containing a monomer mixture containing 5 mol% in the presence of a polymer dispersant soluble in the salt aqueous solution. The papermaking method according to claim 1. 3. The papermaking method according to claim 1, wherein the polymer dispersant is an anionic polymer. 4. The papermaking method according to claim 1, wherein the polymer dispersant is a cationic polymer. 5. The polymer dispersant has an ion equivalent of 1.50 m.
The papermaking method according to any one of claims 1 to 4, wherein the eq / g is equal to or more than eq / g and equal to or less than 15.0 meq / g. 6. The molecular weight of an anionic water-soluble polymer composed of a dispersion produced by a dispersion polymerization method is 1,000,000 or more and 20,000,000 or less.
5. The papermaking method according to any one of 5. 7. The papermaking method according to claim 1, wherein the cationic or amphoteric water-soluble polymer has a molecular weight of 1,000,000 or more and 20,000,000 or less. 8. The papermaking method according to claim 1, wherein the cationic or amphoteric starch has a molecular weight of 50,000 or more and 5,000,000 or less. 9. The papermaking method according to claim 1, wherein the salt constituting the salt aqueous solution is a polyvalent anionic salt. 10. The papermaking method according to claim 1, wherein the papermaking pH is 6.0 to 9.0. 11. One or more of a cationic water-soluble polymer, an amphoteric water-soluble polymer, a cationic starch or an amphoteric starch in a papermaking raw material before papermaking is provided in front of a fan pump or at the entrance of a screen. The papermaking method according to any one of claims 1 to 10, wherein an anionic water-soluble polymer comprising a dispersion produced by a dispersion polymerization method is added at an entrance or an exit of the screen. [0001]