JP3089661B2 - Paper manufacturing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing paper excellent in the effect of improving the yield of fillers or fine fibers, particularly in the papermaking industry, and to a method for producing paper in which the preparation of reagents is easy. Things.

2. Description of the Related Art Paper generally contains inorganic fillers such as kaolin, calcium carbonate, titanium dioxide, clay and talc. These are added internally for the purpose of improving the whiteness, opacity, printability and the like of the paper, and tens of percent may be contained in the dry paper. When producing such a high-filled paper, it is necessary to improve the yield of the filler, the product yield, or the yield of the fine fiber for reducing the burden of white water and wastewater treatment, and to improve the fixing rate. It is common to use retention aids and drainage improvers for the purpose of this purpose. For such purposes, organic polymers such as polyacrylamide, polyethyleneimine, polyamine, epichlorohydrin-modified polyamide polyamine, and polyacrylamide derivatives Compounds and inorganic compounds such as aluminum sulfate are used. In recent years, various systems using combinations of these compounds have been proposed.

For example, a method using a combination of cationic polyacrylamide and anionic polyacrylamide is known as a dual system.

A method using bentonite, which is an inorganic compound, is also known. JP-A-55-152899 discloses a method in which a nonionic polymer is used in combination with a cationic polymer in JP-A-62-191598.

Further, methods for using colloidal silica and a cationic polymer in combination are disclosed in JP-A-57-51900, JP-A-62-15391, and the like.

JP-A-63-235596 discloses a method in which water-swellable cationic polymer particles and a water-soluble polyacrylamide derivative are used in combination.

Problems to be Solved by the Invention However, a sufficient yield effect cannot be obtained only by the organic polymer compound and the inorganic compound exemplified above. There are also some problems with a system that uses them together.

For example, a dual system using a water-soluble polymer of a cation and an anion has a problem that the yield is not so much improved as compared with the single use, and the cost increase by adding two liquids is large.

A common problem with these water-soluble polymers is that the time required for dissolution is very long.

Inorganic compounds such as bentonite and colloidal silica vary greatly in composition, particle shape, etc.In addition, bentonite has a relatively large particle size and lacks surface area, so a large amount of polymer is used together. Therefore, the effect of improving the yield is not sufficient. Moreover, the bentonite itself is colored, and the whiteness after papermaking is slightly reduced.

Colloidal silica also has problems that it requires an extremely large amount of cationic polymer and exhibits a yield effect only in a narrow acidic region. In addition, since the price is high, the cost is increased, which is disadvantageous.

The method using the water-swellable cationic polymer particles,
All are synthetic polymer particles, with relatively little variation. However, since the synthesis method of this polymer is water-in-oil emulsion polymerization, the oil component of the dispersion medium is mixed into the system, the product price is high, and the dissolution time is shorter than that of powder, There is still a problem that it requires a long time and special equipment. Further, the particle size is large and the surface area is not sufficient.

Means for Solving the Problems The present invention has been made in view of the above-mentioned problems, and has been made in view of the above-mentioned polymer emulsion or a water-swellable polymer obtained by reacting the polymer emulsion with an acid, salt, or quaternizing agent. By adding coalesced or these and the vinyl polymer to the stock suspension,
The yield of fillers and fine fibers is remarkably improved.

Further, while the conventional yield improver requires a long time for reagent preparation, this can be easily performed in a remarkably short time.

The present invention will be described in more detail below. Note that the term “(meth) acryl” described in the present specification means both acryl and methacryl. For example, “(meth) acrylate” means both acrylate and methacrylate.

Examples of the monomer (I) represented by the general formula (I) as an essential component of the present invention include diethylaminoethyl (meth) acrylate, dipropylaminoethyl (meth) acrylate, diisopropylaminoethyl (meth) acrylate, dibutyl Aminoethyl (meth) acrylate, diisobutylaminoethyl (meth) acrylate, di-t-butylaminoethyl (meth) acrylate, dipentylaminoethyl (meth) acrylate, dineopentylaminoethyl (meth) acrylate, dihexylaminoethyl (meth) Acrylate, dioctylaminoethyl (meth) acrylate, diethylaminopropyl (meth) acrylamide, dipropylaminopropyl (meth) acrylamide, diisopropylaminopropyl (meth) acrylamide , Dibutylaminopropyl (meth) acrylamide, diisobutylaminopropyl (meth) acrylamide, di-t-butylaminopropyl (meth) acrylamide, dipentylaminopropyl (meth) acrylamide, dineopentylaminopropyl (meth) acrylamide, dihexylaminopropyl ( (Meth) acrylamide, dioctylaminopropyl (meth) acrylamide and the like.

As the crosslinking agent, those which can be copolymerized with the above-mentioned monomer (I) are used. For example, ethylene glycol di (meth)
Acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, 1,2-
Butylene glycol di (meth) acrylate, 1,3-
Butylene glycol di (meth) acrylate, glycerin tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, N, N'-methylenebis (meth) acrylamide, divinylbenzene, divinyl ether, diacrylphthalate, diallyl maleate, diallylamine, Triallylamine, vinyl (meth) acrylate, allyl (meth) acrylate, glycerin di (meth) acrylate, trimethylolpropane tri (meth) acrylate, 2-hydroxy-3-acryloyloxypropyl methacrylate, neopentyl glycol di (meth) acrylate And the amount thereof is 0.005 to 5% by weight, preferably 0.01 to 2% by weight, based on the monomer (I).

If it is less than 0.005% by weight, water swelling properties cannot be obtained even when reacted with an acid, salt or quaternizing agent, and if it exceeds 5% by weight, the water absorption capacity is reduced.

Examples of the monomer (II) to be selectively used include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, and isobutyl. (Meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, neopentyl (meth) acrylate, cyclopentyl (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, n-
Octyl (meth) acrylate, isooctyl (meth)
Acrylate, 2-ethylhexyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, behenyl (Meth) acrylate, phenyl (meth) acrylate, toluyl (meth) acrylate, xylyl (meth) acrylate, benzyl (meth) acrylate, 2
-Phenylethyl (meth) acrylate, isobornyl (meth) acrylate, 2-hydroxyethyl (meth)
Acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-
Hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, p-hydroxyphenyl (meth) acrylate, glycerol mono (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-butoxyethyl (meth) acrylate, 2-phenoxy (meth) acrylate, 2-methoxypropyl (meth)
Acrylate, 3-methoxypropyl (meth) acrylate, 2-ethoxypropyl (meth) acrylate, 3
-Ethoxypropyl (meth) acrylate, 2-methoxybutyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, 4-methoxybutyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, methoxydiethylene glycol (meth) acrylate, Methoxytriethylene glycol (meth) acrylate, methoxydipropylene glycol (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, polybutylene glycol mono (meth) acrylate, dimethylaminoethyl (meth) acrylate Dimethylaminopropyl (meth) acrylate, dimethylaminobutyl (meth) acrylate, 2-sulfoethyl (meth) acryle DOO, 2-sulfopropyl (meth) acrylate, 3-sulfopropyl (meth) acrylate, 2-Surufobuchiru (meth) acrylate,
3-sulfobutyl (meth) acrylate, 4-sulfobutyl (meth) acrylate, 2-phosphoethyl (meth) acrylate, 2-phosphopropyl (meth) acrylate, 3-phosphopropyl (meth) acrylate, 2-phospho Butyl (meth) acrylate, 3-phosphobutyl (meth) acrylate, 4-
(Meth) acrylic acid such as phosphobutyl (meth) acrylate, ethyl succinate (meth) acrylate, ethyl phthalate (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, and trichloroethyl (meth) acrylate Esters, acrylonitrile, styrene and the like can be mentioned, and the added amount thereof is 0 to 70% by weight, preferably 0 to 50% by weight based on all the monomers.

As the surfactant used in the emulsion polymerization, a normal surfactant such as an anionic type, a nonionic type and a cationic type can be used. For example, sodium alkyl benzene sulfonate, alkyl sulfate, sodium alkyl sulfonate, polyoxyethylene alkyl ether Examples include sulfate, polyoxyethylene alkylphenyl ether sulfate, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, alkylamine, betaine type and the like. In general, the combined use of anionic and nonionic surfactants gives a more stable emulsion polymer with less coagulated material.

As a polymerization catalyst to be used, a general radical polymerization initiator such as a peroxide and an azo compound is used, and a water-soluble polymerization initiator is particularly preferable. Examples of the water-soluble polymerization initiator include peroxides such as ammonium persulfate, potassium persulfate, peracetic acid, and hydrogen peroxide, and 2,2'-azobis-2-amidinopropane hydrochloride, 4,4'-azobis- An azo compound such as 4-cyanopentanoic acid is exemplified. When a peroxide is used as an initiator, it may be used as a redox-based initiator in the presence of an appropriate reducing agent, if necessary.

The polymerization may be carried out by an ordinary emulsion polymerization method, and the molecular weight of the obtained polymer can be adjusted to various degrees depending on the use. For example, those having an average molecular weight (viscosity method) of about 100 to 1,000,000 are typical.

Although the polymer emulsion thus obtained does not show water swelling as it is, it is shown in JP-A-2-225507 that it becomes water-swellable by absorbing water by reacting with an acid, salt, or quaternizing agent. ing.

As a reaction method, an emulsion may be added to water to which an acid has been added in advance, or an acid may be added to an emulsion obtained by adding an emulsion to water.

Preferred acids include hydrochloric acid, sulfuric acid, nitric acid, acetic acid, formic acid, maleic acid, fumaric acid, citric acid, tartaric acid, adipic acid, sulfamic acid, toluenesulfonic acid, and the like. Preferred salts include aluminum sulfate, aluminum chloride, There are strong acid weak base salts such as ferric chloride.

As the quaternizing agent, alkyl halides such as methyl chloride, ethyl chloride, methyl bromide and methyl iodide, and general alkylating agents such as dimethyl sulfate and diethyl sulfate can be used.

The amount of the acid, salt or quaternizing agent to be used is 0.3 to 3.0 equivalents, preferably 0.5 to 2.0 equivalents, relative to polymer (I).

In the present invention, a polymer emulsion or an acid,
When a vinyl polymer is used in combination with a water-swellable polymer obtained by reacting with a salt or a quaternizing agent, a high yield effect can be obtained.

As the vinyl polymer, it is possible to use nonionic, anionic, and cation-modified polymers such as an acrylamide polymer, an acrylate polymer, and a vinyl ester polymer obtained by a known method. Is an acrylamide polymer.

The composition is preferably nonionic or anionic, and is preferably an anionic acrylamide-based polymer containing at least 10 mol% of (meth) acrylic acid groups.

Further, the intrinsic viscosity [η] of the solution is 30 ° C., 1N-NaNO
It is preferably about 6 to 20 obtained from the value measured in ₃ , and if it is less than 6, the coagulation effect due to adsorption and crosslinking between particles is small, and if it is too large, the formation of the paper made by the strong coagulation effect becomes poor. Not preferred.

In the present invention, the amount of the water-swellable polymer obtained by reacting the polymer emulsion or the acid, salt, and quaternizing agent with the polymer emulsion is determined based on the solid content of the stock suspension. 0.005% by weight to 0.5% by weight, preferably 0.01 to 0.1%
% By weight.

Since the addition concentration is used in a state where the particles exhibiting water absorption are completely absorbing water, if the water swellability is 1000 times,
0.1% or less of polymer solid content in water, 0.2% in 500 times
In the following, it is preferable to use it after diluting it to 0.05% or less at 2000 times.

As an addition method, when adding as a polymer emulsion, it is diluted and added to an appropriate concentration, and when adding as a water-swellable polymer, it is reacted with an acid, a salt or a quaternizing agent before addition. The polymer emulsion may be added to the stock suspension, and then the acid, salt or quaternizing agent may be added and reacted in the suspension.

When a water-soluble vinyl polymer is used in combination,
The amount of addition is 0 to 0.3% by weight, preferably 0.003 to 0.1% by weight, in terms of polymer solids, based on the solids in the stock suspension. Even if added excessively, the aggregation effect is too high,
The suspension becomes floc and deteriorates the formation of the paper. As a method of addition, generally, it is better to dilute and dissolve the polymer in water to a concentration of about 0.1 to 1%, and to add the polymer emulsion or the water-swellable polymer after adding the polymer, so that the yield improvement is better.

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto. In addition,% in an Example shows a weight% unless there is a notice.

Production Example 1 A stirrer, a cooling pipe, a nitrogen introduction pipe, and a thermometer were attached.
1.5 A four-necked flask was charged with the monomer (I), a crosslinking agent, a surfactant, and 600 g of distilled water. The mixture was deoxygenated with nitrogen gas under stirring, and the contents of the flask were maintained at a predetermined temperature. Next, a catalyst was added and polymerization was carried out for 5 hours.
o / w emulsion was obtained. Table 1 shows the charge amounts.

Production Example 2 In the same flask as in Production Example 1, monomer (I), ethylene glycol dimethacrylate 0.4 g as a cross-linking agent, monomer (II), Emulgen 913 (manufactured by Kao Corporation) 8.0 g, Newcol 271A 4.0 g (manufactured by Nippon Emulsifier Co., Ltd.) and distilled water
After charging 600 g and deoxidizing with nitrogen gas under stirring, the contents of the flask were kept at 15 ° C to 20 ° C. Next, 0.8 g of ammonium persulfate and 0.2 g of sodium bisulfite were added, and polymerization was carried out at 15 ° C. for 5 hours to obtain a milky white o / w emulsion. Table 2 shows the charge amounts.

As the vinyl polymer used in combination, acrylamide / acrylic acid obtained by aqueous solution polymerization = 90/1
0% by weight of copolymer ([η] = 14) (Polymer 1), acrylamide homopolymer ([η] = 13) (Polymer 2)
For comparison, acrylamide / 2-methacryloyloxyethyltrimethylammonium chloride = 75/25 wt% copolymer ([η] = 10) (polymer 3), 2-methacryloyloxyethyltrimethylammonium chloride A homopolymer ([η] = 8.5) (Polymer 4) was used.

Examples 1 to 15, Comparative Examples 1 to 12 Polymer emulsions A to Q obtained in Production Examples 1 and 2,
And Comparative Examples RU and the above-mentioned vinyl polymer 1
The yield test was performed using No.

In addition, polymer emulsions, polymers, etc. in terms of solid content
It was used after being diluted or dissolved to 0.1%.

For stock suspension, 0.8% of NBKP (degree of beating 400ml / CSF)
Diluted with 1.5% aluminum sulphate, 0.5% calcified starch and heavy calcium carbonate escalon as filler
^# 800 (manufactured by Sankyo Seimitsu Co., Ltd.) was added and used as a pulp slurry (provided that the percentage is based on dry weight of pulp).

To this pulp slurry, a polymer emulsion was first added, and after sufficient stirring, a vinyl polymer was added when used together. In addition, the yield test of the heavy calcium carbonate was performed at 800 rpm using a brit type dynamic drainage jar tester (screen 60 mesh).
The results are shown in Table 3.

Examples 16 to 38, Comparative Examples 13 to 16 Water-swellable polymers obtained by reacting the polymer emulsions A to Q and Comparative Examples RU obtained in Production Examples 1 and 2 with an acid, a salt and a quaternizing agent. Was used in the same manner as described above, except that it was diluted to 0.1% in terms of solid content. The results are shown in Table 4.

Examples 39 to 61 and Comparative Examples 17 to 20 The same procedures as described above were carried out except that an acid, a salt and a quaternizing agent were added to the stock suspension and reacted. Table 5 shows the results.

As is clear from Table 3, each of the examples is superior in the yield of heavy calcium carbonate as compared with Comparative Examples 1 to 4 using polymers 1 and 2 alone.

In addition, as in Comparative Example 9, a polymer emulsion using an excessive amount of a crosslinking agent, or as in Comparative Examples 10 to 12, a monomer (I)
Is too small, a sufficient yield effect cannot be obtained with a polymer emulsion.

As is clear from Tables 4 and 5, polymer emulsions containing too little monomer (I) as in Comparative Examples S to U have a lower yield effect than those of Examples. In addition, when compared with Table 3, the polymer emulsion reacted with an acid, salt or quaternizing agent has a better yield effect.

Effect of the Invention According to the present invention, the filler in the stock suspension, the yield effect of fine fibers and the like are superior to the conventional method, and the preparation of the reagent is extremely easy. It is possible to improve the effects of stabilizing the yield in the papermaking process, reducing the amount of chemicals used, recovering white water and reducing the burden on wastewater treatment, and thus improving the technology of the papermaking process.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-225507 (JP, A) JP-A-63-235596 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) D21H 17/00-27/42

Claims (7)

(57) [Claims] (1) General formula (Wherein, R ₁ represents H or CH ₃ , R ₂ and R ₃ represent an alkyl group represented by C _n H _{2n + 1} , _n represents a positive integer, and A represents —O—
Represents CH ₂ — or —NH—CH ₂ —CH ₂ —, and R ₁ , R ₂ , and R ₃ are selected from a range in which the monomer is hardly soluble or insoluble in water. With respect to the monomer (I) and the monomer (I) represented by
0.005 to 5% by weight of a crosslinking agent or monomer (I) and one or more monomers (II) selected from (meth) acrylate, acrylonitrile and styrene
Is less than monomer (I), and a polymer emulsion obtained by emulsion polymerization in water of a mixture containing 0.005 to 5% by weight of a crosslinking agent with respect to all monomers, or an acid, A method for producing paper, comprising adding a water-swellable polymer obtained by reacting with a salt or a quaternizing agent to a stock suspension. 2. The method for producing paper according to claim 1, wherein the monomer (I) is diethylaminoethyl (meth) acrylate. 3. The method according to claim 1, wherein the acid is hydrochloric acid, sulfuric acid, acetic acid, sulfamic acid,
The method for producing paper according to claim 1, wherein the method is selected from phosphoric acid and citric acid. 4. The method according to claim 1, wherein the salt is selected from aluminum sulfate, aluminum chloride and ferric chloride. 5. The quaternizing agent is dimethyl sulfate, diethyl sulfate,
The method for producing paper according to claim 1, wherein the paper is selected from benzyl chloride, methyl chloride, and epichlorohydrin. 6. The paper emulsion according to claim 1, or a water-swellable polymer obtained by reacting it with an acid, salt or quaternizing agent, and a water-soluble vinyl polymer. A method for producing paper, characterized in that it is added to a stock suspension. 7. The method for producing paper according to claim 6, wherein the water-soluble vinyl polymer is an anionic acrylamide polymer containing at least 10 mol% of (meth) acrylic acid groups.