JP2001279595A - Paper making method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the straining properties and the yield of the loading material as well as increase the strength properties in the paper-making system in which a diluted polyacrylamide polymer solution is mixed with an aqueous solution of an aluminum compound and the mixture is added to the pulp slurry. SOLUTION: At least one of dilute solution of amphoteric, cationic and anionic polyacrylamide polymers is mixed with an aqueous solution of a water- soluble aluminum compound and the mixed solution is added to the pulp slurry, then at least one of dilute solutions selected from the amphoteric, cationic and anionic polyacrylamide polymer is added to the resultant pulp slurry.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a papermaking method, and more particularly to an improvement of a papermaking method in a papermaking system in which aluminum sulfate (hereinafter referred to as "sulfate band") does not exert its effect sufficiently under papermaking conditions of pH 6 or more. About.

[0002]

2. Description of the Related Art At present, polyacrylamide-based polymers (PAM) are mainly used as a paper-strengthening agent, and various improvements have been made in terms of composition and polymer structure. The composition is classified into an anionic type, a cationic type, and an amphoteric type. Methods for introducing ionic groups into polyacrylamide-based polymers include copolymerized types obtained by copolymerizing various ionic monomers with acrylamide monomers, and modified types obtained by Hoffman decomposition or Mannich modification of polyacrylamide-based polymers. . Among them, varieties having an ionic composition suitable for various papermaking conditions such as papermaking pH and the amount of added sulfate band are selected and used.

In recent years, recycling of used paper such as newspapers, magazines, and corrugated paper has been accelerated in consideration of protection of the environment and resources, suppression of industrial pollution, and reduction of the social burden of waste disposal. Based on this situation, medium quality coated paper,
Studies are being made at a rapid pace to adapt high quality control standards while using high levels of deinked waste paper (hereinafter also referred to as DIP) in papermaking raw materials such as medium-weight coated base paper and newsprint, as well as lightweight paper. ing. In addition, mechanical pulp tends to be highly blended with the above-mentioned brands and the like because it has a feature that opacity is easily improved as compared with chemical pulp in terms of its optical characteristics.

Various residual chemicals derived from raw materials such as DIP, mechanical pulp, and coated broke, such as surfactants and bleaching agents derived from deinking agents, and dissolved colloid components represented by resin components (hereinafter, referred to as resin components) , DCS), the fixing and adsorption of internal additives such as paper strength enhancers, sizing agents, and sulfuric acid bands are inhibited not only in the neutral pH range but also in the acidic pH range. Has been confirmed to be difficult to exhibit.

On the other hand, there has been proposed a papermaking method in which a diluent of a polyacrylamide-based polymer and an aqueous solution of a water-soluble aluminum compound (hereinafter, also simply referred to as an aluminum compound) are mixed and added to a pulp slurry (Japanese Patent Laid-Open No. 2004-157572). See Japanese Unexamined Patent Publication No. 08-226092). In this papermaking method, the pH of the mixture of the two is acidic, and the aluminum ion derived from the aluminum compound forms an ionic crosslink by coexisting with the polymer as an active cationic species, and the fixing property is maintained without losing its ionicity. It has been confirmed that, at the same time, the polyacrylamide-based polymer undergoes a structural change called high molecular weight, and exhibits excellent strength characteristics.

[0006] The above-mentioned papermaking method is particularly effective for neutral papermaking conditions in which effective cations (charges) are difficult to obtain due to structural changes, such as a sulfate band, among aluminum compounds, or for papermaking systems in which a large amount of DCS is present. This is advantageous in that the fixability of the polyacrylamide-based polymer is further improved, and thereby the strength characteristics are greatly improved. On the other hand, there is a disadvantage in that the structural change of the polyacrylamide-based polymer suppresses the expansion of the polymer chain, and the influence of this results in a decrease in drainage and a decrease in filler yield.

[0007]

SUMMARY OF THE INVENTION In this situation, the present invention relates to a method for mixing a diluent of a polyacrylamide polymer and an aqueous solution of an aluminum compound represented by a sulfuric acid band and adding the resulting mixture to a pulp slurry. It is an object of the present invention to provide a papermaking method capable of improving the disadvantage of lowering the yield and further improving the strength characteristics.

[0008]

Means for Solving the Problems In order to solve the above problems, the present inventors studied the conditions and method of addition of the polyacrylamide-based polymer and the change in the ion distribution of the polymer during the polymerization of the polyacrylamide-based polymer. As a result, the present invention has been completed.

Therefore, the papermaking method according to the present invention provides an amphoteric,
In adding at least one selected from the group consisting of cationic and anionic polyacrylamide-based polymers to the pulp slurry for papermaking, at least one kind selected from the group consisting of amphoteric, cationic and anionic polyacrylamide-based polymers A step of adding a mixed solution obtained by mixing a diluent and an aqueous solution of a water-soluble aluminum compound to a pulp slurry, and adding the mixed solution to the pulp slurry, from the group consisting of amphoteric, cationic and anionic polyacrylamide polymers. At least one chosen
Adding a seed diluent.

Further, the papermaking method according to the present invention provides an amphoteric, cationic and anionic polymer for adding at least one selected from the group consisting of amphoteric, cationic and anionic polyacrylamide-based polymers to a pulp slurry. Mixing an aqueous solution of a water-soluble aluminum compound with at least one diluent selected from the group consisting of hydrophilic polyacrylamide-based polymers, adding the mixed liquid to a pulp slurry, and adding the mixed liquid to the pulp slurry And a step of solely adding at least one diluent selected from the group consisting of amphoteric, cationic and anionic polyacrylamide-based polymers.

The main feature of the present invention is a two-stage addition method in which a diluent of a polyacrylamide polymer and an aqueous solution of an aluminum compound are mixed and immediately added to a pulp slurry, and then a diluent of the polyacrylamide polymer is added alone. It is in. As a result, excellent strength, filler retention, and drainage characteristics are exhibited.

The composition of the polyacrylamide-based polymer used in the two-stage addition system in the present invention can be arbitrarily selected from an anionic type, a cationic type and an amphoteric type, and may be a copolymer type or a modified type. However, an amphoteric copolymer type is preferred in order to maximize the strength, the filler yield, and the drainage characteristics.

The mechanism by which the strength, filler yield, and drainage characteristics are improved by the two-stage addition method is considered as follows.
First, by mixing a polyacrylamide-based polymer diluent and an aqueous solution of an aluminum compound, ionic crosslinking is instantaneously performed to increase the molecular weight. By adding this mixed solution having a high molecular weight and an increased number of contact points (the number of bonding sites) with cellulose to the pulp slurry, the fiber-to-fiber bond becomes strong. Subsequently, by adding a polyacrylamide-based polymer diluent alone, the polymer chain having a large spread forms a stronger inter-fiber bond in a wide range, and the strength characteristics, particularly the internal strength, are greatly improved. This polyacrylamide-based polymer diluent added alone contributes not only to the strength characteristics but also to the improvement of the filler and fine fiber yield and drainage, as compared to the case where the entire amount of the polyacrylamide-based polymer diluent is added alone. It has been confirmed that they exhibit the same or equal filler retention and drainage.

In the two-stage addition method, the addition ratio of the polyacrylamide-based polymer diluent is from 5 to 95 parts by weight, preferably from 30 to 95 parts by weight, as a mixed addition amount with the aluminum compound.
It is preferably adjusted to 70 parts by weight, and 95 to 5 parts by weight, preferably 70 to 30 parts by weight, as a single addition. In addition,
The aluminum compound mixed and added with the polyacrylamide-based polymer is 0.1 to 200 mol%, more preferably 10 to 100 mol%, based on the polymer in terms of aluminum ion.
It is good to add mol%.

In the two-stage addition method, the polyacrylamide-based polymer diluting solution is preferably added at a relatively well-retained portion on the upstream side of the mixed addition with the aluminum compound, for example, at a machine chest. On the other hand,
The single addition can be added anywhere in the process up to the seed box (stuff box) as long as it is after the addition of the mixture with the aluminum compound. It is effective to add at the same location (machine chest, etc.), and if a higher level of drainage and retention characteristics is required within a range that does not hinder the formation of paper, addition in a seed box is effective. It is.

Further, the polyacrylamide-based polymer in the two-stage addition system is an amphoteric polyacrylamide in which a cationic or anionic ionic group is unevenly distributed in a polymer chain, either or both of a mixture and / or a single addition. It has been confirmed that the use of a system polymer further improves the strength characteristics, filler retention, and drainage characteristics. In this case, the polyacrylamide-based polymer has an average molecular weight of 30 in order to ensure the effects expected in the present invention such as improvement in paper quality (strength), drainage, and retention.
It is preferable that the average molecular weight be in the range of 10,000 to 3.5 million, but an average molecular weight out of the above range can be adopted in consideration of the added sample and other conditions.

As a method of effectively applying a polyacrylamide-based polymer having a polymer chain cation or anionic ionic group introduced therein in a non-uniform manner, a charge of a furnish after addition of various chemicals (an inlet slurry in actual machine operation). It is desirable to confirm the state, for example, the zeta potential and the amount of ionic adsorption (ion demand: by colloid titration) in advance. In the case where the charge state is at or near the positive charge side or requires an anionic substance at the ion demand, a polyacrylamide-based polymer in which an anionic group is heterogeneously introduced into a polymer chain is effective. In this case, by applying a polyacrylamide-based polymer having a cationic group introduced heterogeneously, ionic adsorption is further strengthened, and a strong inter-fiber bond is obtained.

A zeta electrometer employing an electrophoresis method or a streaming potential method is used as one of the methods for confirming the charge state. In some cases, the absolute value measured due to the machine difference of the zeta potentiometer is different, but it can be determined whether the charge state of the stock is on the positive charge side or the negative charge side. In addition, the measurement of ion demand generally adopts the colloid titration method. However, the measurement method (method) may be measured using a dedicated measuring device or by manual analysis (titration). At present, measured values are not uniform. However, the behavior of the ionic adsorption state, that is, whether a cationic or anionic substance is required, can be confirmed. An example of the ion demand measurement method is described in the next section.

Cation demand (m · mol / g): 1
50 g of measurement paper material is precisely weighed in a 00 ml beaker and
No. 00N-polycation (20 ml) was added and stirred for 1 minute. 6 Filter with filter paper. In a separate 100 ml beaker, 35 g of the filtrate was accurately weighed and 1/40 using a TB indicator.
Titrate with 0N-PVSK (color change: blue → purple). Anion demand (mmol / g): Perform titration operation reverse to that of cation demand (color change: reddish purple → blue). The same operation is performed with distilled water as a blank test. As chemicals used,
Polycation: dimethyl diallyl ammonium chloride solution, PVSK: polyvinyl potassium sulfate solution, TB
Indicator: 0.1% toluidine blue solution. Whether the stock requires a cationic or anionic substance can be determined by the value of the anion / cation demand ratio (CTR). That is, when the CTR is larger than 1, an anionic substance is required, and when the CTR is smaller by one twist, a cationic substance is required.

The acrylamides used in producing the copolymer type polyacrylamide polymer used in the present invention include, for example, acrylamide, methacrylamide, N-methylacrylamide, N-ethylacrylamide, N, N-dimethylacrylamide. , N-isopropylacrylamide, diacetone acrylamide, etc., and water-soluble N-substituted lower alkyl acrylamides, and these can be used alone or in combination of two or more.

As a monomer copolymerized with acrylamides, nonionic monomers other than ionic monomers having anions and / or cations can be used.

Examples of the anionic monomer include monocarboxylic acids such as acrylic acid, methacrylic acid and crotonic acid, dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid, citraconic acid and muconic acid, and salts thereof. In addition, it is also possible to use organic sulfonic acids such as vinyl sulfonic acid, styrene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid and salts thereof, and these may be used alone or in combination of two or more. Can also be used in combination. Further, it is preferable to use a carboxylic acid monomer having a strong interaction with the aluminum compound in combination.

Examples of the cationic monomer include tertiary amine monomers such as dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylamide, diethylaminopropyl (meth) acrylamide, allylamine and diallylamine. Or salts of inorganic or organic acids such as hydrochloric acid, sulfuric acid, and acetic acid; and ammonium salt-based monomers obtained by quaternizing a tertiary amine-based monomer with methyl chloride, benzyl chloride, dimethyl sulfate, epichlorohydrin, and the like. be able to. These ionic monomers can be used alone or in combination of two or more.

The nonionic monomer can be used to such an extent that the water solubility of the polymer is not impaired, and examples thereof include (meth) acrylonitrile, styrene and vinyl acetate.

It is also possible to use a small amount of a crosslinking agent, for example, methylenebis (meth) acrylamide,
Bis (meth) acrylamides such as ethylene bis (meth) acrylamide, bis (meth) acrylamide-methylol ethylene urea condensate, bis (meth) acrylamide-methylol urea, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate Di (meth) acrylates, such as divinyl adipate and divinyl sebacate, N, N-diallylacrylamide, 1,2,3-triacloylhexahydro-S-triazine, triallyl isocyanurate, etc. And a trivinyl monomer-based cross-linking agent. The addition amount of these crosslinking agents is 0.005 to 1 mol%, preferably 0.01 to 0.2 mol%, based on the total amount of the monomers.

The polymer can be polymerized by various known methods. For example, the above-mentioned various monomers and water are charged into a predetermined reaction vessel, and a persulfate such as potassium persulfate or ammonium persulfate or a redox-based polymerization initiator obtained by combining these with a reducing agent such as ammonium hydrogen sulfite is used. A desired polymer can be obtained by adding a radical polymerization initiator or an azo-based polymerization initiator, and optionally using a chain transfer agent such as isopropyl alcohol and allyl alcohol as needed, and heating under stirring. . The 8 to 15% by weight aqueous solution of the polyacrylamide-based polymer thus obtained is 25% by weight.
The viscosity measured by a Brookfield viscometer at 100 ° C. is 100 to 40,000 mPa · s.
It is preferably from 00 to 20,000 mPa · s.

In the case of amphoteric polyacrylamide-based polymers in which cationic or anionic ionic groups are distributed unevenly in the polymer chain, one of ionic monomers such as cationic or anionic monomers may be used during the above-mentioned polymerization process. By charging a part or the whole amount, an ionic group can be heterogeneously introduced into a polymer chain, and other basic polymerization methods are the same.

The aluminum compound that can be used in the present invention has a different content ratio as long as it is water-soluble, but any of them can be used. Examples of the aluminum compound include polyaluminum chloride, alumina sol, polyaluminum sulfate, polyaluminum silicate, aluminum chloride, and aluminum sulfate. These aluminum compounds can be used alone or in combination of two or more. In particular, aluminum sulfate (sulfuric acid band) often used in the papermaking process is preferable in terms of handling and cost.

The mixing of the aluminum compound with the polyacrylamide-based polymer is desirably diluted so that the viscosity of the polymer is not increased by mixing and the workability is not impaired. The dilution concentration of the polymer varies depending on the composition and cannot be determined unconditionally, but is within 0.1 to 8% by weight, preferably 0.1 to 8% by weight.
It is about 2 to 3% by weight.

The mixing time is preferably from immediately before addition to the pulp slurry to 10 hours before the addition, more preferably within 1 hour before the addition. However, in actual use, it is most preferable to use an aqueous solution of an aluminum compound mixed with a diluted chemical (polyacrylamide-based polymer) immediately before addition. The amount of the aluminum compound added was as described above, but was 0.1% with respect to the polymer in terms of aluminum.
It is preferably from 200 to 200 mol%, more preferably from 10 to 100 mol%.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below with reference to examples, but the present invention is by no means limited to only these examples. Various polyacrylamide-based copolymers used as paper strength agents in Examples and Comparative Examples were prepared as follows. In the following, "%" means "% by weight" unless otherwise specified.

[0032]

[Production Example 1 of Polyacrylamide Polymer] 632 g of water, 271.2 g of 50% acrylamide, and 3.90 g of itaconic acid were placed in a 1 L four-necked flask equipped with a stirrer, thermometer, reflux condenser and nitrogen gas inlet tube. , Dimethylaminoethyl methacrylate (9.42 g) and isopropyl alcohol (3.0 g) were prepared, and adjusted with an acid or an alkali so that the pH became about 3.0. Oxygen was removed by passing nitrogen gas through the reaction system. Next, the temperature was raised to 65 ° C. while stirring, and a 5% ammonium persulfate solution 1 was used as a polymerization initiator.
5 g and 10 g of 5% sodium sulfite were charged to initiate polymerization. Thereafter, the temperature was maintained at 90 ° C. for 30 minutes to terminate the polymerization. Non-volatile content 15.9%, viscosity 8700 mPa · s,
This polymer having a constant number of pH 4.1 is abbreviated as A-1. Hereinafter, polymers A-2 to A-5 were obtained in the same manner as in the above Production Examples by changing the amounts of the monomers corresponding to the compositions shown in Table 1 and the amounts of the appropriate catalysts and chain transfer agents. Was.

[0033]

[Production Example 2 of Polyacrylamide Polymer] A 625 g of water, 271.2 g of 50% acrylamide, and 2.60 g of itaconic acid were placed in a 1 L four-necked flask equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas inlet tube. , Dimethylaminoethyl methacrylate (9.42 g) and isopropyl alcohol (3.0 g) were prepared, and adjusted with an acid or an alkali so that the pH became about 3.0. Oxygen was removed by passing nitrogen gas through the reaction system. Next, the temperature was raised to 65 ° C. while stirring, and a 5% ammonium persulfate solution 1 was used as a polymerization initiator.
5 g and 10 g of 5% sodium sulfite were charged to initiate polymerization. In the next step, add water 44
g and 1.30 g of itaconic acid, and the mixture is adjusted with an acid or an alkali so that the pH becomes about 3.0. The state was maintained for 30 minutes to complete the polymerization. Non-volatile content 15.3%, viscosity 8000mPa ・
This polymer having a constant of pH s and pH 4.1 is abbreviated as A-6. Hereinafter, polymers A-7 to A-9 were obtained by changing the amounts of the monomers and the appropriate catalysts and chain transfer agents corresponding to the compositions shown in Table 1 in the same manner as in the above Production Example. Was.

[0034]

[Production Example 3 of Polyacrylamide Polymer] 615 g of water, 271.2 g of 50% acrylamide, and 3.90 g of itaconic acid were placed in a 1 L four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube. And 6.28 g of dimethylaminoethyl methacrylate and 3.0 g of isopropyl alcohol, and the mixture is adjusted with an acid or an alkali so that the pH becomes about 3.0. Oxygen was removed by passing nitrogen gas through the reaction system. Next, the temperature was raised to 65 ° C. while stirring, and a 5% ammonium persulfate solution 1 was used as a polymerization initiator.
5 g and 10 g of 5% sodium sulfite were charged to initiate polymerization. In the next step, add water 44
g, 3.14 g of dimethylaminoethyl methacrylate, and the mixture is adjusted with an acid or an alkali so that the pH becomes about 3.0. The state was maintained for 30 minutes to complete the polymerization. Nonvolatile content 1
This polymer having a constant of 5.4%, a viscosity of 8900 mPa · s and a pH of 4.0 is abbreviated as A-10. Hereinafter, polymers A-11 and A12 were obtained in the same manner as in the above Production Examples by changing the amounts of the monomers corresponding to the compositions shown in Table 1 and the amounts of the appropriate catalysts and chain transfer agents.

[0035]

[Table 1]

The abbreviations of the monomers in Table 1 are as follows. AM: acrylamide IA: itaconic acid FA: fumaric acid DM: dimethylaminoethyl methacrylate DM-Q: methyl chloride quaternary product of DMDMAEA-Q: methyl quaternary chloride of dimethylaminoethyl acrylate DMAPAA-Q: methyl chloride of DMAPAA Quaternary compound

[0037]

Example 1 A bleached kraft pulp (LBKP) sheet was beaten with a Niagara beater to a volume of 470 ml using a Canadian Standard Freeness (CSF) tester. The beaten pulp is adjusted to 3% concentration with city water,
The light conductivity was measured at 650 μS / cm after light calcium carbonate was added at 10% by weight based on pulp and the pulp slurry was sufficiently stirred. After further stirring the pulp slurry, the sulfuric acid band 5% diluted solution shown in Table 2 was added.

Subsequently, a 1% dilution of the polyacrylamide-based polymers A-1 to 5 obtained above was mixed with a 5% dilution of a sulfuric acid band in the amount shown in Table 2 and added to the pulp slurry. Thereafter, 1% dilutions of A-1 to A-5 were added alone. Further, the pulp slurry concentration was diluted to 1.2% by introducing city water while continuing stirring, and the retention agent (trade name: N
R-12MLS: manufactured by Hymo Co.)
Was added.

Table 2 shows the addition amounts of A-1 to A-5 (the ratios of addition and single addition with the sulfate band). Table 3 shows the relationship between each chemical and the timing of its addition. Further, when the ion demand was measured for the final stock to which A-1 was added in Example 1, the cation demand was 0.21 m · mol / g, the anion demand was 0.18 m · mol / g, and the anion / cation The demand ratio was 0.86.

On the other hand, a paper having a basis weight of 48 g / m ² was prepared from the obtained pulp slurry using a square sheet machine.
After pressing for 1 minute at Kg / cm ² , it was dried at 105 ° C. for 3 minutes to prepare a test paper. 23 ° C / 50% RH
After adjusting the humidity for 24 hours under the conditions described above, the internal strength using an internal bond tester manufactured by Kumagai Riki and JISP8128
The ash content at 600 ° C. for 1 hour was measured in accordance with the above. In addition, C.I. S. F
Freeness (0.3% concentration, corrected at 20 ° C.). Table 2 shows various measurement results. Fixing / papermaking pH is 7.
8

[0041]

COMPARATIVE EXAMPLE 1 Light calcium carbonate was added to a pulp slurry in the same manner as in Example 1, then a 2% sulfuric acid band was added to the pulp weight, followed by one of the polyacrylamide polymers A-1 to A-5 obtained above. % Dilution was added. Hereinafter, handmade paper was prepared under the same conditions as in Example 1 and the measurement was performed. The freeness was also measured in the same manner.

[0042]

Comparative Example 2 As in Example 1, light calcium carbonate was added to the pulp slurry, and then the amount of sulfuric acid band shown in Table 2 was added. Subsequently, a 1% dilution of the polyacrylamide-based polymers A-1 to 5 obtained above was mixed with a sulfuric acid band in an amount shown in Table 2 and added to the pulp slurry. Hereinafter, handmade paper was prepared under the same conditions as in Example 1 and the measurement was performed. The freeness was also measured in the same manner.

[0043]

[Table 2]

[0044]

[Table 3]

[0045]

Example 2 After light calcium carbonate was added to the pulp slurry under the same conditions as in Example 1, the 5% diluted sulfuric acid band shown in Table 4 was added. Subsequently, the polyacrylamide-based polymers A-1, 4, 7, 8, 10, 1 and 2 obtained above were obtained.
The sulfuric acid band 5% diluents in the amounts shown in Table 4 were mixed with the 1% diluents 1 and 12 and added to the pulp slurry. Thereafter, 1% dilutions of A-1, 4, 7, 8, 10, 11, and 12 were independently added. Further, the pulp slurry concentration was diluted to 1.2% by introducing city water while stirring was continued, and a retention agent (trade name: NR-12MLS: manufactured by Hymo) was added at 120 ppm as a solid content.

Table 4 shows the addition amounts of the above-mentioned polymers (mixing addition with the sulfuric acid band and addition ratio alone). Table 5 shows the relationship between each chemical and the timing of its addition. Further, when the ion demand was measured for the final stock to which A-1 was added in Example 2, the cation demand was 0.21 m · mol / g, the anion demand was 0.18 m · mol / g, and the anion / cation was measured. The demand ratio was 0.86.

On the other hand, a paper having a basis weight of 48 g / m ² was prepared from the obtained pulp slurry using a square sheet machine.
After pressing for 1 minute at Kg / cm ² , it was dried at 105 ° C. for 3 minutes to prepare a test paper. 23 ° C / 50% RH
After adjusting the humidity for 24 hours under the conditions described above, the internal strength using an internal bond tester manufactured by Kumagai Riki and JISP8128
The ash content at 600 ° C. for one hour was measured according to the method described in the above. In addition, C.I. S. F
Freeness (0.3% concentration, corrected at 20 ° C.). Table 4 shows various measurement results. Fixing / papermaking pH is 7.
8

[0048]

Comparative Example 3 As in Example 2, light calcium carbonate was added to the pulp slurry, and then the amount of sulfate band shown in Table 4 was added. Subsequently, one of the polyacrylamide-based polymers A-1, 4, 7, 8, 10, 11, 12 obtained above was obtained.
The sulfuric acid band of the amount shown in Table 4 was mixed with the% diluted solution and added to the pulp slurry. Hereinafter, handmade paper was prepared under the same conditions as in Example 2 and the measurement was performed. The freeness was also measured in the same manner.

[0049]

[Table 4]

[0050]

[Table 5]

[0051]

Example 3 Light calcium carbonate was added to a pulp slurry under the same conditions as in Examples 1 and 2, followed by amphoteric starch (trade name).
Cato 3210: NSC Japan Ltd.) was added in an amount of 0.6% by weight to pulp, and a 5% sulfuric acid band 5% dilution as shown in Table 6 was added. Subsequently, 1% of the polyacrylamide-based polymer A-1, 4, 6, 7, 8, 11, or 12 obtained above.
The diluent was mixed with a sulfuric acid band 5% diluent in the amount shown in Table 4 and added to the pulp slurry. Then A-1,
4, 6, 7, 8, 11, 12 1% dilutions were added alone. Further, the pulp slurry concentration was diluted to 1.2% by introducing city water while stirring was continued, and a retention agent (trade name: NR-12MLS: manufactured by Hymo) was solidified at 120 p.
pm was added.

Table 6 shows the amounts of the above-mentioned polymers added (the ratio of the addition with the sulfuric acid band and the addition alone). Table 7 shows the relationship between each chemical and the timing of its addition. Further, when the ion demand was measured for the final stock to which A-1 was added in Example 3, the cation demand was 0.16 m · mol / g, the anion demand was 0.25 m · mol / g, and the anion / cation was measured. The demand ratio was 1.56.

On the other hand, a paper having a basis weight of 48 g / m ² was prepared from the obtained pulp slurry using a square sheet machine.
After pressing for 1 minute at Kg / cm ² , it was dried at 105 ° C. for 3 minutes to prepare a test paper. In addition, 23 ° C, 50% R
After adjusting the humidity for 24 hours under the conditions of H, the internal strength using an internal bond tester manufactured by Kumagai Riki and JISP812
The ash content at 600 ° C. for 1 hour was measured according to 8. In addition, C.I. S. F
Freeness (0.3% concentration, corrected at 20 ° C.). Table 6 shows various measurement results. Fixing / papermaking pH is 7.
8

[0054]

Comparative Example 4 Light calcium carbonate was added to a pulp slurry in the same manner as in Examples 1 and 2, and then 0.6% of amphoteric starch was added.
Then, the amount of the sulfuric acid band shown in Table 6 was added. Subsequently, the polyacrylamide-based polymer A-1 obtained above,
The sulfuric acid bands of the addition amounts shown in Table 4 were mixed with the 1% dilutions of 4, 6, 7, 8, 11, and 12, and added to the pulp slurry. Hereinafter, handmade paper was prepared under the same conditions as in Example 3 and the measurement was performed. The freeness was also measured in the same manner.

[0055]

[Table 6]

[0056]

[Table 7]

[0057]

Example 4 A bleached kraft pulp (LBKP) sheet was beaten with a Niagara beater to a volume of 470 ml using a Canadian Standard Freeness (CSF) tester. The beaten pulp is adjusted to 3% concentration with city water,
After adding 5% of light calcium carbonate and 5% of kaolin to pulp by weight and sufficiently stirring the pulp slurry, the electric conductivity was measured to be 630 μS / cm. This pulp slurry is mixed with amphoteric starch (trade name Cato3210:
0.6% by pulp weight and a 5% sulfuric acid band 5% diluent shown in Table 8 were added.

Subsequently, a 1% dilution of the polyacrylamide-based polymer A-1, 4, 6, 7, 8, 11, or 12 obtained above was mixed with a 5% dilution of a sulfuric acid band in the amount shown in Table 8. And added to the pulp slurry. After that, A-1, 4,
6,7,8,11,12 1% dilutions were added alone. Further, the pulp slurry concentration was diluted to 1.2% by introducing city water while stirring was continued, and the retention agent (NR-1) was used.
2MLS: manufactured by Hyomo) was added at a solid content of 120 ppm.

A-1, 4, 6, 7, 8, 11, 12
Table 8 shows the addition amount of the compound (addition ratio of the mixture addition with the sulfuric acid band and the single addition). Table 9 shows the relationship between each chemical and the timing of its addition. Further, when the ion demand was measured for the final stock to which A-1 was added in Example 4, the cation demand was 0.17 m · mo.
1 / g, the anion demand was 0.23 mmol / g, and the anion / cation demand ratio was 1.35.

On the other hand, the obtained pulp slurry was used to make paper having a basis weight of 48 g / m ² using a square sheet machine.
After pressing for 1 minute at Kg / cm ² , it was dried at 105 ° C. for 3 minutes to prepare a test paper. 23 ° C / 50% RH
After adjusting the humidity for 24 hours under the conditions described above, the internal strength using an internal bond tester manufactured by Kumagai Riki and JISP8128
The ash content at 600 ° C. for one hour was measured according to the method described in the above. In addition, C.I. S. F
Freeness (0.3% concentration, corrected at 20 ° C.). Table 8 shows various measurement results. Fixing / papermaking pH is 7.
8

[0061]

Comparative Example 5 Light calcium carbonate and kaolin were added to a pulp slurry in the same manner as in Example 4, and then the amphoteric starch was added to 0.1%.
6% and the amount of sulfate band indicated in Table 8 was added.
Subsequently, the polyacrylamide-based polymer A-
The sulfuric acid bands of the addition amounts shown in Table 5 were mixed with the 1% dilutions of 1, 4, 6, 7, 8, 11, and 12, and added to the pulp slurry. Hereinafter, handmade paper was prepared under the same conditions as in Example 4 and the measurement was performed. The freeness was also measured in the same manner.

[0062]

[Table 8]

[0063]

[Table 9]

[0064]

Example 5 A bleached kraft pulp (LBKP) sheet was beaten with a Niagara beater to a volume of 470 ml using a Canadian Standard Freeness (CSF) tester. The beaten pulp is adjusted to 3% concentration with city water,
The light conductivity was measured at 650 μS / cm after light calcium carbonate was added at 10% by weight based on pulp and the pulp slurry was sufficiently stirred. After further stirring the pulp slurry, the sulfuric acid band 5% diluent shown in Table 10 was added.

Subsequently, a 1% dilution of the polyacrylamide-based polymers A-1, 4 and 5 obtained above was mixed with a 5% dilution of a sulfuric acid band shown in Table 10 and added to the pulp slurry. Thereafter, 1% dilutions of A-1, 6, 7, 8, and 9 were independently added. Further, the pulp slurry concentration was diluted to 1.2% by introducing city water while stirring was continued, and a retention agent (trade name: NR-12MLS: manufactured by Hymo) was added at 120 ppm as a solid content.

Table 10 shows the addition amounts of A-1, 4, 5, 6, 7, 8, and 9 (the ratio of the addition to the sulfate band and the addition of the single addition). Table 11 shows the relationship between each chemical and the timing of its addition. Further, when the ion demand was measured for the final stock to which A-1 (A-1) was added in Example 5, the cation demand was 0.1%.
21mmol / g, anion demand 0.18m
mol / g and the anion / cation demand ratio was 0.86.

On the other hand, the obtained pulp slurry was used to make paper having a basis weight of 48 g / m ² using a square sheet machine.
After pressing for 1 minute at Kg / cm ² , it was dried at 105 ° C. for 3 minutes to prepare a test paper. 23 ° C / 50% RH
After adjusting the humidity for 24 hours under the conditions described above, the internal strength using an internal bond tester manufactured by Kumagai Riki and JISP8128
The ash content at 600 ° C. for 1 hour was measured in accordance with the above. In addition, C.I. S. F
Freeness (0.3% concentration, corrected at 20 ° C.). Table 10 shows various measurement results. The fixing / papermaking pH is 7.8.

[0068]

[Table 10]

[0069]

[Table 11]

[0070]

Example 6 A 5% diluted solution of sulfuric acid band and a 1% diluted solution of polyacrylamide-based polymers A-1 and A-4 were mixed and added to a pulp slurry.
The same operation as in Example 5 was performed except that the 1% diluents of -1, 10, 11, and 12 were added alone, and the internal strength, ash content, and freeness were measured in the same manner as in Example 5. Table 12 shows various measurement results.

Table 1 shows the amounts of the above-mentioned polymers to be tested (the ratio of the addition of the polymer to the sulfuric acid band and the addition of the polymer alone).
Table 2 shows the relationship between each chemical and the timing of its addition. Further, when the ion demand was measured for the final stock to which A-1 (A-1) was added in Example 6, the cation demand was 0.21 m · mol / g and the anion demand was 0.18 m · mol / g. And the anion / cation demand ratio was 0.86. Also,
The fixing / papermaking pH is 7.8.

[0072]

[Table 12]

[0073]

[Table 13]

[0074]

Example 7 A 5% diluted solution of sulfuric acid band and the amount of polyacrylamide-based polymer A-7, 8, 9 in the amount shown in Table 14 were added.
% Diluent was added to the pulp slurry, and then the same operation as in Example 5 was performed, except that the 1% diluents A-1, 4, 5, and 7 were added alone. The internal strength, the ash content, and the freeness were measured in the same manner as described above. Table 14 shows various measurement results.

Table 1 shows the amounts of the above-mentioned polymers tested (the mixing ratio of the polymer and the single addition with the sulfuric acid band).
Table 4 shows the relationship between each chemical and the timing of its addition. Further, when the ion demand was measured for the final stock to which A-7 (A-7) was added in Example 7, the cation demand was 0.22 m · mol / g and the anion demand was 0.18 m · mol / g. Yes, the anion / cation demand ratio was 0.82. Also,
The fixing / papermaking pH is 7.8.

[0076]

[Table 14]

[0077]

[Table 15]

[0078]

Example 8 A sulfuric acid band 5% diluent having an addition amount shown in Table 16 and polyacrylamide-based polymer A-6, 7, 8-1
% Diluent was added and added to the pulp slurry, and then the same operation as in Example 5 was performed, except that the 1% diluents of A-10, 11, and 12 were added alone. Was measured for internal strength, ash content and freeness. Table 16 shows various measurement results.

Table 1 shows the amounts of the above-mentioned polymers (mixing ratio with the sulfuric acid band and ratio of single addition).
Table 6 shows the relationship between each chemical and the timing of its addition. Further, A-6 (A-10) in Example 8
When the ion demand was measured for the final stock to which was added, the cation demand was 0.20 mmol · g / g,
The anion demand was 0.19 mmol / g and the anion / cation demand ratio was 0.95. The fixing / papermaking pH is 7.8.

[0080]

[Table 16]

[0081]

[Table 17]

[0082]

Example 9 A 5% sulfuric acid band diluted solution and polyacrylamide polymer A-10, 11, 1 were added in the amounts shown in Table 18.
2 and 1% diluent mixed and added to the pulp slurry,
Thereafter, the same operation as in Example 5 was performed, except that the 1% diluted solution of A-1, 4, 5 was added alone, and the internal strength, ash content, and freeness were measured in the same manner as in Example 5. Table 18 shows various measurement results.

Table 1 shows the amounts of the above-mentioned polymers (mixing ratio with sulfuric acid band and addition ratio alone).
Table 8 shows the relationship between each chemical and the timing of its addition. Further, A-10 (A-1) in Example 9
When the ion demand was measured for the final stock to which was added, the cation demand was 0.21 mmol · g / g,
The anion demand was 0.19 mmol / g and the anion / cation demand ratio was 0.90. The fixing / papermaking pH is 7.8.

[0084]

[Table 18]

[0085]

[Table 19]

[0086]

Example 10 A 5% sulfuric acid band diluted solution having the addition amounts shown in Table 20 and polyacrylamide polymers A-10, 11,
The same operation as in Example 5 was performed except that a 1% diluent of A-6, 7, 8, and 9 was added alone after mixing with the 1% diluent of No. 12 and adding to the pulp slurry. Example 5
The internal strength, the ash content, and the freeness were measured in the same manner as described above. Table 20 shows various measurement results.

Table 2 shows the amounts of the above-mentioned polymers (mixing ratio with the sulfuric acid band and addition ratio alone).
Table 21 shows the relationship between each chemical and the timing of its addition. Further, A-10 (A-
When the ion demand was measured for the final stock to which 6) was added, the cation demand was 0.21 mmol · mol / mol.
g, anion demand was 0.18 mmol / g, and anion / cation demand ratio was 0.86. The fixing / papermaking pH is 7.8.

[0088]

[Table 20]

[0089]

[Table 21]

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yoshiharu Kimura 471, No.7, Mizuashi, Noguchi-cho, Kakogawa-shi, Hyogo F-term in the Technical Development Department, Harima Chemicals Co., Ltd. 4L055 AA01 AG08 AG12 AG73 AH01 AH09 AH16 AH18 AH50 BD11 BD13 EA30 EA32 FA08 FA10 FA13

Claims (7)

[Claims] Claims: 1. An amphoteric, cationic and anionic polyacrylamide-based polymer, wherein at least one selected from the group consisting of amphoteric, cationic and anionic polyacrylamide-based polymers is added to a pulp slurry to make paper. A mixture of at least one diluent selected from and an aqueous solution of a water-soluble aluminum compound,
A step of adding at least one diluent selected from the group consisting of amphoteric, cationic and anionic polyacrylamide polymers to the pulp slurry to which the mixture has been added. A papermaking method, characterized in that: 2. A paper made of amphoteric, cationic and anionic polyacrylamide-based polymers, in which at least one selected from the group consisting of amphoteric, cationic and anionic polyacrylamide-based polymers is added to a pulp slurry for papermaking. Mixing an aqueous solution of a water-soluble aluminum compound with at least one diluent selected from the group consisting of: a step of adding the mixture to a pulp slurry; and an amphoteric, cationic, and anionic form in the pulp slurry to which the mixture is added. A single step of adding at least one diluent selected from the group consisting of hydrophilic polyacrylamide-based polymers. 3. The amount of at least one diluent selected from the group consisting of amphoteric, cationic and anionic polyacrylamide-based polymers added to the pulp slurry in an amount of 5 to 95% by weight when the mixture is added, 95-
3. The papermaking method according to claim 1, wherein the weight is adjusted to 5% by weight. 4. An amphoteric polyacrylamide-based polymer in which cation or anion ionic groups are non-uniformly distributed in a polymer chain when the mixture is added and / or when the mixture is added alone. 4. The papermaking method according to any one of claims 1 to 3. 5. The papermaking method according to claim 4, wherein the amphoteric polyacrylamide-based polymer has an average molecular weight of 300,000 to 3.5 million. 6. A pulp slurry before adding a mixture obtained by mixing at least one diluent selected from the group consisting of amphoteric, cationic and anionic polyacrylamide-based polymers with an aqueous solution of a water-soluble aluminum compound,
The papermaking method according to any one of claims 1 to 5, wherein an aqueous solution of a water-soluble aluminum compound is added. 7. A pulp slurry before adding a mixed diluent obtained by mixing at least one diluent selected from the group consisting of amphoteric, cationic and anionic polyacrylamide polymers with an aqueous solution of a water-soluble aluminum compound. The papermaking method according to any one of claims 1 to 6, wherein a filler is added.