JP2002227093A - Papermaking method for neutral newsprint paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing neutral newsprint paper using a paper stock containing a filler consisting mainly of calcium carbonate through an efficient papermaking process under neutral to weakly alkaline conditions in high yield with minimal pitch troubles. SOLUTION: This method for producing neutral newsprint paper comprises incorporating a paper stock prior to papermaking with (A) a cationic water-soluble polymer and/or polycondensate-based cationic substance and making a treatment and then adding (B) an anionic water-soluble polymer to the system followed by conducting a papermaking operation; wherein it is preferable that the anionic water-soluble polymer is in the form of polymeric microparticles <=100 μm in size and produced by dispersion polymerization process in an aqueous salt solution in the presence of a polymeric dispersant soluble to the aqueous salt solution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a papermaking method for producing newsprint under neutral papermaking conditions. More specifically, the present invention relates to a papermaking method containing a filler mainly composed of calcium carbonate before papermaking. The present invention relates to a method for producing a neutral newsprint that is capable of forming a newsprint at a high yield after treating with a water-soluble cationic substance, adding an anionic water-soluble polymer, and making a paper with a paper machine. is there.

[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).

On the other hand, newsprint has conventionally been made under acidic conditions in which a sulfuric acid band coexists in the papermaking raw material. The reason is that the mixing ratio of mechanical pulp is high in the raw material for newsprint. So-called pitch is easily generated from mechanical pulp. The sulfate band regulates the surface charge of pitch particles, which is a water-insoluble component, to prevent pitch particles from agglomerating and to suppress the occurrence of trouble.

[0004] The so-called pitch in the papermaking process is a water-insoluble and sticky substance. The pitches include those derived from wood and those derived from latex and others used in the papermaking process. Wood-derived materials include oils and fats, fatty acids, terpenes, steroids, natural resins, gums, and the like, which remain after pulping.
In the subsequent papermaking process, these sticky substances are released and are dispersed in a colloidal state, but the colloidal state is destroyed by strong shearing force, rapid pH change, addition of a sulfate band, etc., and aggregation, The pitch becomes coarse, so-called pitch. On the other hand, the pitch derived from the paper processing substance is such that the colloidal state is also destroyed while the latex such as a coat block in the coat paper manufacturing process is recycled at the wet end, and the pitch in the same coat block is reduced. It coagulates with calcium carbonate, coarsens, and forms a white pitch deposit on the paper after papermaking, causing trouble.

[0005] For the above-mentioned reasons, it has been common sense that newsprint is usually made of acidic paper. However, in recent years, as the recycling rate of used newspaper has further increased, the proportion of advertising leaflets in the used paper has increased. This flyer contains a large amount of calcium carbonate as a filler. Conventionally,
When newsprint was made acidic, a process of neutralizing the calcium carbonate with an acid and then making the paper was employed. However, due to the large amount of calcium carbonate, the amount of acid used is very large, and the production cost is beginning to be affected. Further, by neutralization, a large amount of dissolved salts coexist in the papermaking raw material slurry, and there is a concern that the quality of the paper or the effect on the papermaking process may be affected.

[0006] As a method for making medium-sized paper containing a large amount of mechanical pulp in the papermaking raw material, a combination of polyethylene oxide and sulfonated phenol-formaldehyde resin, which is hardly affected by anionic substances contained in mechanical pulp and waste paper, is used. Is known. (Japanese Patent Laid-Open No. 9-1889
No. 93). However, since this method uses formalin and a substance suspected of disturbing endocrine such as bisphenol A and bisphenol S as a resin raw material, there is a concern about the influence on the environment.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for making newsprint paper from neutral to weakly alkaline using a papermaking raw material containing a filler mainly composed of calcium carbonate.
It is an object of the present invention to develop a production method for producing paper at a high yield with little pitch trouble.

[0008]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the following inventions have been reached. That is, the invention of claim 1 of the present invention comprises adding a polymerizable cationic water-soluble polymer and / or a polycondensation cationic material (A) to a papermaking raw material before papermaking containing a filler mainly composed of calcium carbonate, The present invention relates to a method for making neutral newsprint, which comprises adding an anionic water-soluble polymer (B) after the treatment.

According to a second aspect of the present invention, the anionic water-soluble polymer (B) comprises 5 to 100 mol% of (meth) acrylic acid, 0 to 95 mol% of acrylamide and other copolymerizable monomer 0 A polymer mixture having a particle size of 100 μm or less 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. A method for making neutral newsprint according to claim 1.

According to a third aspect of the present invention, the polymerizable cationic water-soluble polymer (A) contains 10 to 100 mol% of a monomer represented by the following general formula (1) and / or the following general formula (2). A monomer mixture containing 0-90 mol% of acrylamide and 0-20 mol% of other copolymerizable monomers,
In a salt aqueous solution, in the presence of a polymer dispersant soluble in the salt aqueous solution,
2. The method according to claim 1, comprising polymer fine particles having a particle diameter of 100 μm or less produced by a dispersion polymerization method.

Embedded image R1 is hydrogen or a methyl group, R2 is a methyl group or an ethyl group, R3 is a methyl group or an ethyl group, and R4 is a C1 to C1 group.
8, an alkyl group or a benzyl group, A is an oxygen atom or NH, B is a C2-C3 alkylene group or alkoxylene group, X1 is an anion

Embedded image R5 is hydrogen or methyl, R6 is methyl, ethyl or benzyl, R7 is methyl, ethyl or benzyl, X2 is an anion

The invention of claim 4 is the neutral newsprint according to claim 1 or 2, wherein the molecular weight of the anionic water-soluble polymer (B) is 1,000,000 or more and 20,000,000 or less. Is a method of making paper.

The invention of claim 5 is characterized in that the molecular weight of the polymerizable cationic water-soluble polymer and / or the polycondensation cationic substance (A) is 1,000 or more and less than 5,000,000. Alternatively, it is a method of making the neutral newsprint described in 3.

[0013] The invention of claim 6 provides a polymerizable cationic water-soluble polymer and / or a polycondensation cationic material (A),
6. An anionic water-soluble polymer is added at at least one of a seed box, a front of a fan pump or an entrance of a screen, and an anionic water-soluble polymer is added at an entrance or an exit of a screen. The method for producing neutral newsprint described in (1).

[0014] The invention of claim 7 is that the cationic water-soluble polymer (A) is added in an amount of 200 per dry solid content of papermaking raw material.
2,000 ppm, the amount of the anionic water-soluble polymer (B) added is 200-1000 pp per dry solid content of papermaking raw material.
m. The method of making neutral newsprint according to claim 1, wherein m is m.

The invention of claim 8 is characterized in that the papermaking pH is 6.0 to 6.0.
The method for making neutral newsprint according to any one of claims 1 to 7, wherein the neutral newsprint is 9.0.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The cationic water-soluble substance used in the present invention is a polycondensation-type cationic substance or a polymerization-type cationic polymer. Alternatively, both can be used in combination. The polycondensation-based cationic substance is a polycondensation product of at least one compound selected from ammonia, aliphatic monoamine and aliphatic polyamine with epihalohydrin. Examples of aliphatic monoamines and aliphatic polyamines include monomethylamine, monoethylamine, dimethylamine, diethylamine, trimethylamine, triethylamine, mono, di, and triethanolamines, and ethylenediamine, diethylenetriamine, and triethylenetetramine. And pentaethylenehexamine. A polycondensate can be obtained by reacting one or more of these ammonia and amines with an epihalohydrin such as epichlorohydrin.
These polycondensates do not require the amines and epihalohydrin to react in a single step; the first step is a reaction with an aliphatic monovalent amine, followed by a cross-linking reaction with ammonia or an aliphatic polyamine to increase the molecular weight of the polycondensation. Products may be manufactured. The molecular weight of these polycondensates is 500 to 2
Million, preferably 1,000 to 2,000,000.

On the other hand, the polymerizable polymer is a homopolymer of a cationic vinyl monomer or a copolymer with a nonionic water-soluble monomer. The vinyl monomer is one or more homopolymers or copolymers of cationic monomers containing a quaternary ammonium base. Among the quaternary ammonium base-containing monomers, acrylic examples include (meth) acryloyloxyethyltrimethylammonium chloride,
(Meth) acryloyloxy 2-hydroxypropyltrimethylammonium chloride, (meth) acryloylaminopropyltrimethylammonium chloride, (meth)
Acryloyloxyethyl dimethylbenzylammonium chloride, (meth) acryloyloxy 2-hydroxypropyldimethylbenzylammonium chloride, (meth) acryloylaminopropyldimethylbenzylammonium chloride, etc., and diallylamine-based monomers such as dimethyldiallylammonium chloride And so on.

Also, a copolymer with a nonionic monomer can be used. Examples of nonionic monomers include (meth) acrylamide, examples of nonionic monomers,
N, N-dimethylacrylamide, vinyl acetate, acrylonitrile, methyl acrylate, (meth) acrylic acid 2
-Hydroxyethyl, diacetone acrylamide, N-
Vinyl pyrrolidone, N-vinyl formamide, N-vinyl acetamide and the like. The molar percentage of the cationic monomer in these polymers is 10 to 100 mol%, preferably 15 to 100 mol%, for both acrylic and diallylamine monomers.

The molecular weight of these cationic water-soluble polymers or copolymers is from 10,000 to 5,000,000, preferably from 100,000 to 3,000,000. If it is less than 10,000, the effect is not sufficient, and if it is higher than 3,000,000, the effect does not change much and there is no merit.

For the (co) polymerization of these cationic or nonionic monomers, known polymerization methods can be applied.
For example, aqueous solution polymerization, water-in-oil emulsion polymerization,
It is an aqueous solution, a water-in-oil emulsion, a powder or a dispersion in an aqueous salt solution which is in various product forms obtained by a water-in-oil type dispersion polymerization method, a salt aqueous solution dispersion polymerization method, or the like. The most preferred product form is a dispersion polymerized product in an aqueous salt solution.

A water-soluble polymer comprising a polymer fine particle dispersion liquid dispersed in a salt aqueous solution is prepared by adding a cationic monomer or a cationic monomer and a nonionic monomer to a salt aqueous solution. It can be manufactured with stirring in the presence of a dispersant composed of a soluble polymer. The dispersant composed of a polymer soluble in an aqueous salt solution can be used as an ionic or nonionic polymer, but is preferably an ionic polymer. As the ionic polymer, a homopolymer of dimethyldiallylammonium chloride or (meth) acryloyloxyethyltrimethylammonium chloride or a copolymer with a nonionic monomer is used. The molecular weight is 5,000 to 3,000,000, preferably 50,000 to 20
100,000. As the nonionic polymer, polyvinylpyrrolidone, acrylamide / polyvinylcaprolactam copolymer, acrylamide / styrene copolymer,
Alternatively, a water-soluble polymer having an amide group and a slight hydrophobic group such as a completely amidated maleic anhydride / butene copolymer is effective, and has a molecular weight of 1,000 to 200,000, preferably 1,000. ~ 50,000.

As the inorganic salts constituting the salt aqueous solution, polyvalent anion salts are more preferable, and sulfates or phosphates are suitable. Specific examples thereof include ammonium sulfate, sodium sulfate, magnesium sulfate, aluminum sulfate, and ammonium hydrogen phosphate. , Sodium hydrogen phosphate, potassium hydrogen phosphate, and the like. These salts are preferably used as an aqueous solution having a concentration of 15% or more.

In the case of polymerizing a diallylamine or acrylic monomer or copolymerizing with a nonionic monomer, the aqueous monomer solution is adjusted to pH 2 to 2 regardless of the polymerization method.
After adjusting to 7, the solution was deoxygenated in a nitrogen stream, and then a radical polymerization initiator was added to initiate polymerization. The initiator may be a redox system such as a combination of ammonium peroxodisulfate and sodium bisulfite, a peroxide such as hydrogen peroxide or lauryl peroxide, a solvent-soluble azobisisobutyronitrile, a water-soluble 2,2-azo compound. Bisamidinopropane dichloride or 2,2-azobis [2-
(5-Methyl-2-imidazin-2-yl) propane] It is properly used depending on the polymerization method or polymerization conditions with monomers such as azo compounds such as dihydrochloride.

Next, the anionic water-soluble polymer used in the present invention will be described. The polymer is a homopolymer of (meth) acrylic acid or a copolymer with acrylamide or the like, and is prepared by an existing polymerization method, such as aqueous solution polymerization, water-in-oil emulsion polymerization, and water-in-oil dispersion. Examples of the aqueous solution, water-in-oil emulsions, powders, and dispersions in aqueous salt solutions, which are various product forms obtained by a polymerization method, a dispersion polymerization method in an aqueous salt solution, and the like. The most preferred form of polymerization is an anionic water-soluble polymer comprising a dispersion produced by a dispersion polymerization method in the presence of a dispersant comprising a polymer dissolved in the flame aqueous solution in a salt aqueous solution.

In this polymerization method, a water-soluble monomer containing (meth) acrylic acid is produced by a dispersion polymerization method while stirring in an aqueous salt solution in the presence of a dispersant comprising a polymer soluble in the aqueous salt solution. Is done. As the anionic monomer used,
Examples include methacrylic acid, acrylic acid, maleic 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, 2-hydroxyethyl (meth) acrylate,
Diacetone acrylamide, N-vinylpyrrolidone, N
-Vinylformamide, N-vinylacetamide and the like, and copolymerization with one or more of these anionic monomers or nonionic monomers is possible. The most preferred combination is
Acrylic acid and acrylamide. The proportion of these anionic monomers in the (co) polymer is 5 to 100 mol%, preferably 10 to 100 mol%.

The anionic water-soluble polymer comprising the polymer fine particle dispersion used in the present invention will be described more specifically. (Meth) acrylic acid used as a raw material is introduced into an aqueous solution of a polyvalent anion salt, 10 to 20 mol% thereof is neutralized, and a polymer soluble in the aqueous salt solution is allowed to coexist as a dispersant.

The polymerization conditions are usually determined as appropriate depending on the monomers used and the molar percentage of copolymer.
Perform at 0 ° 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, 4,4-azobis (4-methoxy-2,
4-dimethylvaleronitrile) 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 most preferred initiator is a redox initiator.

The dispersant composed of a polymer soluble in an aqueous salt solution used for the polymerization can be used as an ionic or nonionic polymer, but is preferably an ionic polymer, and more preferably an ionic polymer. It is an anionic polymer. As the cationic polymer, a homopolymer of dimethyldiallylammonium chloride or (meth) acryloyloxyethyltrimethylammonium chloride or a copolymer with a nonionic monomer is used.

On the other hand, as the anionic dispersion, a (co) polymer of an anionic monomer such as acrylamide 2-methylpropanesulfonic acid (salt) and styrenesulfonic acid (salt) can be used. These anionic monomers and carboxyl group-containing monomers, for example, acrylic acid, methacrylic acid,
Copolymers with itaconic acid and the like can also be used. Further, non-ionic monomers such as acrylamide, N-vinylformamide, N-vinylacetamide, N-vinylpyrrolidone, N, N-dimethylacrylamide, acrylonitrile, diacetoneacrylamide, and 2-hydroxyethyl (meth) acryle Copolymers such as those described above can also be used. Further, a partially amidated maleic anhydride / butene copolymer may be used.

The molecular weight of these ionic polymer dispersants is 5,000 to 3,000,000, preferably 50,000 to 2,000,000.
One million. Examples of the nonionic polymer dispersant include amide groups and some hydrophobic groups such as polyvinylpyrrolidone, acrylamide / polyvinylcaprolactam copolymer, acrylamide / styrene copolymer, maleic anhydride / butene copolymer, and the like. Is effective, and the molecular weight is from 1,000 to 200,000, preferably from 1,000 to 50,000.

The molecular weight of the polymer constituting the dispersion is from 1,000,000 to 20,000,000, preferably 500
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.

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, 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 20 mPa · s. 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 produced in the aqueous salt solution, but the detailed mechanism is not elucidated. 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.

In the method for producing neutral newsprint of the present invention, newsprint recovered as used paper and fillers mainly composed of calcium carbonate contained in advertising printed matter mixed therein are made together. Conventionally, calcium carbonate contained in such fillers has been neutralized and dissolved by an acid.However, this method is disadvantageous in terms of cost and increases the concentration of inorganic salts in papermaking water to a high level. It also has a significant effect on the quality of the paper made. Instead, if it is incorporated into newsprint, it will save paper quality and resources, and it will be a great deal.

However, a point to be considered here is that the possibility that so-called pitches, which cause stains on the formed paper, are mixed in from the old leaflets increases. The so-called pitch in the papermaking process is a water-insoluble and sticky substance. The pitches include those derived from wood and those derived from latex and others used in the papermaking process. Wood-derived materials include oils and fats, fatty acids, terpenes, steroids, natural resins, gums, and the like, which remain after pulping. In the subsequent papermaking process, these sticky substances are released and are dispersed in a colloidal state, but the colloidal state is destroyed by strong shearing force, rapid pH change, addition of a sulfate band, etc., and aggregation, The pitch becomes coarse, so-called pitch.

Therefore, the first addition of the cationic water-soluble polymer of the present invention also has the meaning of neutralizing the surface charge of the pitch component particles in order to prevent such agglomeration of the pitch component that causes stains. . It also has an effect of appropriately adjusting the surface charge of the pulp fiber and the filler to effectively perform the coagulation action by the anionic water-soluble polymer added later.

The pulp contained in the target newsprint raw material is a coated block, used newspaper, used magazine, or used flyer, and the mechanical pulp is groundwood pulp, refiner groundwood pulp, or the like. Pressurized groundwood pulp, thermomechanical pulp and chemithermomechanical pulp.

The content of calcium carbonate in the papermaking raw material is about 15 to 50% by weight, and the content in the paper after papermaking is 7 to 15% by weight. This calcium carbonate is mainly derived from the filler in the waste flyer paper and the surface coat layer. In addition, other talc and clay are mixed in as a filler, but the content is smaller than that of calcium carbonate which is inexpensive in terms of cost.

The cationic water-soluble polymer of the present invention is added at the entrance of a seed box, a fan pump or a screen. It is also effective to divide them into two parts at these positions. In addition, the anionic water-soluble polymer is screen-based.
Basically, it is added at the entrance or exit of the
It is preferred to add at a relatively short position to the paper machine.

The amount of the cationic water-soluble polymer to be added is 200 ppm to 2,000 with respect to the solid content of the papermaking raw material.
ppm, preferably from 300 pm to 1000 ppm
It is. The amount of the anionic water-soluble polymer added is 200 ppm to 2000 ppm based on the solid content of the papermaking raw material.
And preferably from 200 ppm to 1000 ppm. These addition amounts are relatively high compared to general retention agents and fixing agents, but are sufficiently economical in consideration of the acid neutralization treatment cost of the filler. The papermaking pH applicable to the papermaking method of the present invention is 6.0 to 6.0.
It is most advantageous to carry out in the range of 9.0.

[0039]

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) A polycondensation-based cationic substance (sample-1) composed of dimethylamine / epichlorohydrin / pentaethylenehexamine by an aqueous solution polymerization method, and
Polymerized cationic water-soluble polymers containing quaternary ammonium bases (Samples 2 to 4) were synthesized. Composition of each sample,
The molecular weight and cation equivalent were measured. The molecular weight is measured by a static light scattering method (Otsuka Electronics DLS-7000)
And the weight average molecular weight was measured. Table 1 shows the results.

(Synthesis Example 2) In a 500 mL four-necked flask equipped with a thermometer, a stirrer, a nitrogen inlet tube, a monomer supply tube connected to a peristaltic pump (SMP-21, manufactured by Tokyo Rika Kikai) and a condenser. Dimethyldiallylammonium chloride (hereinafter abbreviated as DD) (trade name DADM)
AC, 65% by weight, manufactured by Daiso) 31.1 g, acrylamide 17.8 g (trade name: acrylic amide, manufactured by Nitto Chemical, 50% product), ion-exchanged water 107.2 g, ammonium sulfate 64.0 g, sodium sulfate 5 Of acryloyloxyethyltrimethylammonium chloride homopolymer as a dispersant (8.3 g, 20 wt% liquid, viscosity 8530 mPa · s), and the temperature in the reactor was kept at 42 ° C. and the atmosphere was replaced with nitrogen for 30 minutes. Thereafter, 10% of 2,2′-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride is used as an initiator.
% Aqueous solution (0.15% of monomer) was added to initiate polymerization. Separately, the acrylamide 142.1
g, ion-exchanged water 27.5 g, ammonium sulfate 73.
267.2 g of a solution prepared by mixing 3 g, 6.7 g of sodium sulfate and 17.8 g of a dispersant was prepared. After the start, 53.4 g of this solution was added for 1.5 hours. Thereafter, at an interval of 1.5 hours, 106.8 g, 80.1 g and 26.7 g, respectively.
g was added. The molar ratio of DD to acrylamide after supplying all the monomers is 10:90. After the start 4.
In 5 hours, 0.35 g of the initiator solution was added. 20 after the start
The reaction was stopped at time. After the polymerization, the cation equivalent was measured by a colloid titration method, and the viscosity and the weight average molecular weight of the dispersion were measured. This polymer is designated as Sample-5. In a similar manner, a molar ratio of DD to acrylamide of 30:70 was synthesized (sample-6). Table 1 shows the results.

(Synthesis Example 3) A five-necked separable flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen inlet tube was prepared as follows:
16.7 g of a 15% aqueous solution of acryloyloxyethyltrimethylammonium chloride (hereinafter abbreviated as DMQ) homopolymer, 139 g of ion-exchanged water, 112.5 g of ammonium sulfate, 50% aqueous acrylamide (hereinafter A)
AM) 175.1 g and 80% aqueous acryloyloxyethyltrimethylammonium chloride 3
After charging 3.1 g and purging with nitrogen, 1.9 g of a 1% aqueous solution of 2,2′-azobis (2-amidinopropane) hydrochloride was prepared.
Was added and polymerization was carried out at an internal temperature of 35 ° C. for 10 hours. The polymer particle size in the obtained dispersion was 10 μm or less, and the viscosity of the dispersion was 500 cp. The molar composition of the indented monomer is DMQ: AAM = 10: 90 (sample-
7). Table 1 shows the results.

(Synthesis Example 4) By the same synthesis method as in Synthesis Example 1, acryloyloxyethyldimethylbenzylammonium chloride: DMQ: AA = 10: 20: 7
0 (mol%) was synthesized (sample-8). Table 1 shows the results.

(Synthesis Example 5) Acryloyloxyethyldimethylbenzylammonium chloride: DMQ: AA was prepared in the same manner as in Synthesis Example 1 except that the polymer dispersant was changed to a completely amidated maleic anhydride / butene copolymer.
= 10:20:70 (mol%) (sample-
9). Table 1 shows the results.

(Synthesis Example 6) 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 designated as Sample-10. The molar ratio of acrylic acid to acrylamide in Sample-10 was 3
0:70 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. In addition, the weight average molecular weight was measured by a molecular weight measuring device (DLS-7000 manufactured by Otsuka Electronics Co., Ltd.) by a static light scattering method. Table 2 shows the results.

(Synthesis Example 6) Acrylic acid was used in the same manner as in Synthesis Example 6, except that the polymer dispersant was changed to acryloyloxyethyltrimethylammonium chloride homopolymer (20% by weight, viscosity 8300 mPa · s, 25 ° C.). Sample-11 having a acrylamide molar ratio 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 2 shows the results.

(Synthesis Example 7) A sample 12 having a molar ratio of acrylic acid to acrylamide of 50:50 was synthesized by the same operation as in Synthesis Example 6. The viscosity of this prototype is 130 mPa
-It was s. In addition, as a result of microscopic observation, 5-20 μm
Particles. The molecular weight was measured in the same manner as in Synthesis Example-1. Table 2 shows the results.

(Synthesis Example 8) The polymer dispersant was changed to a completely amidated maleic anhydride / butene copolymer, and the molar ratio of acrylic acid to acrylamide was 30:70 as in Synthesis Example 6.
Was synthesized. The viscosity of this prototype is 940m
Pa · s. In addition, as a result of microscopic observation, 5-20
It was found to be particles of μm. The molecular weight was measured in the same manner as in Synthesis Example-1. Table 2 shows the results.

(Comparative Synthesis Example 1) In the same manner as in Synthesis Example-1 and Synthesis Example-2, an aqueous solution polymerization product and a dispersion polymerization product of dimethyldiallylammonium chloride / acrylamide polymer = 5/95 were synthesized as comparative products. (Comparative-1, Comparative-2). After the synthesis, the molecular weight and the cation equivalent value were measured in the same manner. The results are shown in Table 3.

(Comparative Synthesis Example 2) In the same manner as in Synthesis Example 3, an aqueous polymer product and a dispersion polymer product of acryloyloxyethyltrimethylammonium chloride / acrylamide copolymer 5/95 (molar ratio) (Comparative-3, Comparative -4) and a tertiary amine acrylic monomer, dimethylaminoethyl acrylate homopolymer (Comparative-5), and the monomer / acrylamide copolymer = 30/70 (Comparative-6) Were respectively synthesized. The results are shown in Table 3.

[0051]

Examples 1 to 23 Papermaking raw materials collected from a papermaking site were blended in the following manner: 15% by weight of a coat block, 20% by weight of recovered pulp and 65% by weight of deinked pulp (DIP).
7,870 ppm, ash, 1370 ppm, pH7.
A papermaking raw material dispersion for test No. 06 was prepared. This dispersion 5
00 ml is sampled and put into a brit type dynamic jaw tester to measure the yield. The measurement conditions and operation are as follows. 2000 rpm of stirring rotation
m, and the mixture was stirred for 10 seconds.
ppm, and stirred for 20 seconds. After that, the number of revolutions
000 rpm, and the mixture was stirred for 10 seconds. Then, 300 ppm of the solid content of the raw material for papermaking was added to the anionic water-soluble polymer sample-10 and sample-11 in Table 2 and stirred for 10 seconds. Next, the cock for discharging white water was opened, the white water was discarded for the first 10 seconds, and the white water for the next 30 seconds was collected. Sample-2 to Sample-4 and Sample-7 as cationic water-soluble polymers
~ Sample-8, powdered product (sodium acrylate / acrylamide = 30/7) as an anionic water-soluble polymer
A test was also conducted using a 0 mol% copolymer, a molecular weight of 10,000,000) (referred to as Sample-14). The wire used was a 125P screen (equivalent to 200 mesh), and the total yield (SS concentration) was ADVANTEC 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 4 shows the results.

[0052]

Comparative Examples 1 to 10 Comparative tests were carried out using the test papermaking raw material dispersions used in Examples 1 to 23. When the papermaking raw material was not treated with the cationic water-soluble polymer and only the anionic water-soluble polymer samples -10 and -12 were added and tested, the cationic water-soluble polymer was compared with Comparative-1 to Comparative-6. Was used, and Sample-10 was used as the anionic polymer, and Sample-7 was used as the cationic water-soluble polymer.
~ Using sample-8, the amount of papermaking raw material added was 150 ppm,
Sample 10 was used as the anionic water-soluble polymer, and a test was performed for a case where the amount of raw material added to paper was 150 ppm. Table 5 shows the results.

[0053]

Examples 24 to 46 The same papermaking raw materials as in Examples 1 to 23 were blended in the following manner: 25% by weight of a coat block, 25% by weight of recovered pulp and 50% by weight of deinked pulp (DIP).
S content, 85500 ppm, ash content, 1800 ppm, pH
A papermaking raw material dispersion for test of 8.03 was prepared. 500 ml of this dispersion is collected and subjected to a brit type dynamic jar.
The yield was measured by a tester. 200 stirring speed
After setting to 0 rpm and stirring for 10 seconds, the cationic water-soluble polymer samples-1 to -9 shown in Table 1 were added to the papermaking raw material solids at 400 ppm and stirred for 20 seconds. Thereafter, the rotation speed was reduced to 1000 rpm, and the mixture was stirred for 10 seconds.
Anionic water-soluble polymer, sample-11 or sample-
13 was added to the papermaking raw material solids at 300 ppm and stirred for 10 seconds. Next, the cock for discharging white water and white water was opened, white water was discarded for the first 10 seconds, and white water for the next 30 seconds was collected. Similarly, sample-2 to sample-4 and sample-7 to sample-8 were used as cationic water-soluble polymers, and powdered products (sodium acrylate / acrylamide = 30/70 mol% copolymer) were used as anionic water-soluble polymers. Substance, molecular weight 1000
(10) was also tested at the same time. The wire used was a 125P screen (2
And the total yield (SS concentration) is A
DVANTEC 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 6 shows the results.

[0054]

Comparative Examples 11 to 20 Comparative tests were carried out using the test papermaking raw material dispersions used in Examples 24 to 46. When the papermaking raw material was not treated with the cationic water-soluble polymer, and only the anionic water-soluble polymer sample-11 or sample-13 was added and tested, the comparison was made as the cationic water-soluble polymer-1 to -6. When the anionic water-soluble polymer is used in combination with Sample-11, using Sample-2 to Sample-4 and Sample-7 to Sample-8 as the cationic water-soluble polymer, and adding 150 ppm to papermaking raw material, As an anionic water-soluble polymer, the amount of raw material added to paper was 15
The test was performed for the case of 0 ppm. Table 7 shows the results.

[0055]

[Table 1] In sample-1, pentaethylenehexamine was compared to EPI
Add 7 mol%. DA: dimethylamine, EPI: epichlorohydrin, DMQ: acryloyloxyethyltrimethylammonium chloride DD: dimethyldiallylammonium chloride ABC: acryloyloxyethylbenzyldimethylmethylammonium chloride AAM: acrylamide Liquid viscosity: mPa · s, sample -1 is a 50% aqueous solution, sample-
2 to 4 are 20% aqueous solutions, samples 5 to 8 are 25% dispersions, cation equivalent: meq / g, molecular weight: unit is 10,000

[0056]

[Table 2] AAC: acrylic acid, AAM: acrylamide, liquid viscosity: mPa · s, molecular weight: unit is 10,000

[0057]

[Table 3] DMQ: acryloyloxyethyltrimethylammonium chloride DD: dimethyldiallylammonium chloride AAM: acrylamide, DMA: dimethylaminoethyl acrylate Liquid viscosity: mPa · s, cation equivalent meq / g, molecular weight: 10,000

[0058]

[Table 4] Amount added: ppm, total yield: weight%, ash yield: weight%

[0059]

[Table 5] Amount added: ppm, total yield: weight%, ash yield: weight%

[0060]

[Table 6] Amount added: ppm, total yield: weight%, ash yield: weight%

[0061]

[Table 7] Amount added: ppm, total yield: weight%, ash yield: weight%

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08F 220/60 C08F 220/60 226/04 226/04 D21H 17/43 D21H 17/43 17/45 17 / 45

Claims (7)

[Claims] 1. A polymerizable cationic water-soluble polymer and / or a polycondensation-type cationic substance (A) are added to a papermaking raw material before papermaking containing a filler mainly composed of calcium carbonate, and the mixture is treated with an anionic water-soluble polymer. A method for making neutral newsprint, characterized by adding a reactive polymer (B). 2. The method according to claim 1, wherein the anionic water-soluble polymer (B) is
A monomer mixture containing 5 to 100 mol% of (meth) acrylic acid, 0 to 95 mol% of acrylamide and 0 to 20 mol% of another copolymerizable monomer can be added to the aqueous salt solution. 2. A method for making neutral newsprint according to claim 1, comprising polymer fine particles having a particle diameter of 100 [mu] m or less produced by a dispersion polymerization method in the presence of a soluble polymer dispersant. 3. The polymerizable cationic water-soluble polymer (A) contains 10 to 100 mol% of a monomer represented by the following general formula (1) and / or the following general formula (2) and 0 to 100% of acrylamide. A monomer mixture containing 90 mol% and 0 to 20 mol% of other copolymerizable nonionic monomers is dispersed in a salt aqueous solution in the presence of a polymer dispersant soluble in the salt aqueous solution. 2. A method for making neutral newsprint according to claim 1, comprising polymer fine particles having a particle size of 100 [mu] m or less produced by a legal method. Embedded image R1 is hydrogen or a methyl group, R2 is a methyl group or an ethyl group, R3 is a methyl group or an ethyl group, and R4 is a C1 to C1 group.
8 is an alkyl group or a benzyl group, A is an oxygen atom or NH, B is a C2 to C3 alkylene group or alkoxylene group, and X is an anion. R5 is hydrogen or methyl, R6 methyl, ethyl or benzyl, R7 is methyl, ethyl or benzyl, X is anion 4. The method for making a neutral newsprint according to claim 1, wherein the molecular weight of the anionic water-soluble polymer (B) is 1,000,000 or more and 20,000,000 or less. 5. The polymerizable cationic water-soluble polymer and / or polycondensation cationic substance (A) has a molecular weight of 1
4. The method for making neutral newsprint according to claim 1 or 3, wherein the number is from 000 to 5,000,000. 6. The polymerization-based cationic water-soluble polymer and / or the polycondensation-based cationic substance (A) is added at least at one of a seed box, a fan pump, and a screen entrance. 6. A method for making neutral newsprint according to claim 1, wherein an anionic water-soluble polymer is added at the entrance or exit of the screen. 6. The addition amount of the polymerizable cationic water-soluble polymer and / or the polycondensation-based cationic substance (A) is 200 to 2000 ppm per dry solid content of papermaking raw material, and the anionic water-soluble polymer (B) is used. The method for making neutral newsprint according to any one of claims 1 to 5, wherein the addition amount of the neutral newsprint is 200 to 1000 ppm based on the dry solid content of the papermaking raw material. 7. The method for making neutral newsprint according to claim 1, wherein the papermaking pH is 6.0 to 9.0.