WO2015053349A1

WO2015053349A1 - Retention aid and method for producing paper by using same

Info

Publication number: WO2015053349A1
Application number: PCT/JP2014/077024
Authority: WO
Inventors: 孝一但木; 浩之大石; 一孝春日; 裕太望月; 幸裕藤田
Original assignee: ソマール株式会社
Priority date: 2013-10-08
Filing date: 2014-10-08
Publication date: 2015-04-16
Also published as: JPWO2015053349A1; CN105612288B; CN105612288A; JP6509121B2

Abstract

Provided are a retention aid and a method for producing paper by using the same which make it possible to produce paper having a high filler content and having the filler uniformly dispersed therein, without sacrificing paper-production-step operability or paper formation properties, regardless of paper type. This method involves adding the following retention aid to a pulp-containing aqueous slurry before and/or after passage through a screen: a retention aid containing a cationic or anionic polymer compound having a viscosity-average molecular weight of over 35,000,000, wherein the cationic or anionic charge density in the cationic or anionic polymer compound is 0.6-4.0 meq/g.

Description

Yield agent and paper manufacturing method using the same

INDUSTRIAL APPLICABILITY The present invention can produce a paper having a high content of waste paper and filler and uniformly dispersed without impairing the operability and the physical properties of the paper in the papermaking process, and regardless of the type of paper. The present invention relates to a yield agent and a method for producing paper using the same.

In recent years, pulp made from recycled paper is often used due to environmental problems such as global warming and effective use of resources. As the paper to be recycled, for example, newspaper paper, magazines, copy paper, cardboard, and the like, and recently, paper that is shredded from the office or the like, which is called shredder dust, is increasing.

In general, recycled pulp has a shorter pulp fiber length than that of virgin pulp, so when manufacturing paper using recycled pulp, a yield agent is usually used to improve the overall yield. It has been. The improvement in the overall yield is obtained by creating an aggregate of pulp components (hereinafter referred to as floc). This retention agent is usually added before and after passing through a shearing process such as a fan pump or a screen. Therefore, the formed flocs need cohesiveness that does not collapse even when a large shear force is applied.

However, in recent years, various fillers such as calcium carbonate, talc, clay, and white carbon tend to be added at a high blending amount in order to improve the whiteness, opacity, printability, etc. of the paper. . In the method for producing paper using the above-mentioned yield agent, when producing paper using recycled pulp, the filler and the deinked waste paper pulp (hereinafter referred to as “DIP”) that did not yield due to the low yield of the filler, Pitch components derived from various types of pulp components contained in coated broke pulp, etc., aggregate and adhere to the paper machine and paper surface, causing paper machine dirt and paper surface defects. As a result, operability and productivity are reduced. However, the amount of filler added tends to increase due to the improvement of paper quality, environmental problems, and cost reduction, and there has been a problem that the yields that have been used so far cannot be fully effective.

Therefore, a papermaking aid (Patent Document 1) composed of a cationic polymer having a viscosity average molecular weight of 100,000 to 1,000,000 has been proposed. However, as the operating speed of the paper machine increases to improve productivity, the shearing force in the shearing process of fan pumps, screens, etc. increases, and the formed flocs tend to collapse. There was room for improvement in terms of yield in the previous addition.

On the other hand, after forming a floc using a cationic substance as a retention agent, passing through a shearing process and further making a paper by adding an anionic substance to a pulp slurry as a retention additive (Patent Document 2), A method for producing paper (Patent Document 3) and the like in which an anionic water-soluble polymer having improved dispersibility in a pulp component with an inorganic salt or an inorganic acid has been proposed.

In these methods, by combining two or more retention agents having different ionic properties, flocs can be aggregated again to form flocs even if they disintegrate once, but the total amount of retention agent added is large. As a result, the pulp component causes excessive agglomeration, resulting in larger flocs, which reduces the uniformity of the paper thickness (hereinafter referred to as “texture properties”), and the operability of the paper machine is disadvantageous. .

JP 2006-89864 A JP 2001-254290 A JP 2001-295196 A

In this way, with the recent increase in the ratio of used paper and fillers in paper production and the speed of paper production, paper quality has been further improved, storage stability, and paper machine corrosion problems have been improved. Because of the advantages such as being obtained, instead of using conventional acid paper with a large amount of sulfuric acid bands, neutral papers that do not use sulfuric acid bands or that make papers near neutrality by reducing the use of sulfuric acid bands. Production increased.

Accordingly, an object of the present invention is to produce a paper having a high filler content and uniformly dispersed without impairing the operability and the physical properties of the paper in the papermaking process, and regardless of the type of paper. It is to provide a yield agent that can be used.

As a result of intensive studies to solve the above problems, the inventors of the present invention obtained a retention agent containing a cationic compound or anionic polymer compound having a low charge density and a viscosity average molecular weight exceeding 35 million. By adding to the pulp-containing aqueous slurry at least one before and after passing through the slurry, it is not necessary to add a retention agent having different ionicity, and it is a floc that does not easily collapse even with a large shearing force with a small addition amount It is found that paper can be made without deteriorating the physical properties of the components even if the yield of each component is good. It came to complete.

That is, the retention agent of the present invention contains a cationic or anionic polymer compound having a viscosity average molecular weight exceeding 35 million, and the cationic or anionic polymer compound has a cation or anion charge density of 0.6. It is characterized by being -4.0 meq / g.

Further, the paper manufacturing method of the present invention is a paper manufacturing method including a step of papermaking after passing the pulp-containing aqueous slurry through a screen, and at least one of the high-pressure slurry before passing through the screen and after passing through the screen. The retention agent of the present invention is added to the pulp-containing aqueous slurry so that the concentration of the molecular compound is less than 500 ppm with respect to the pulp component.

In the paper manufacturing method of the present invention, it is preferable to add 5 to 60% by mass of a filler to the pulp-containing aqueous slurry with respect to the pulp. Moreover, it is preferable that the manufacturing method of the paper of this invention adds the said retention agent to the pulp containing aqueous slurry after passing a screen. Furthermore, in the paper manufacturing method of the present invention, it is preferable to add the retention agent to the pulp-containing aqueous slurry before passing through the screen and the pulp-containing aqueous slurry after passing through the screen.

According to the present invention, it is possible to produce a paper having a high content of waste paper and filler and uniformly dispersed without impairing the operability and the physical properties of the paper in the paper making process, and regardless of the type of paper. It is possible to provide a yield agent that can be used and a method for producing paper using the same.

FIG. 1 is a flowchart showing the addition position of a retention agent in the method of the present invention. FIG. 2 is a scanning electron microscope (SEM) photograph of a cross section of the paper obtained in Example 2-11 of the present invention. FIG. 3 is a scanning electron microscope (SEM) photograph of the cross section of the paper obtained in Comparative Example 2-10.

Hereinafter, embodiments of the present invention will be described in detail.
First, the retention agent of the present invention will be described. The retention agent used in the present invention is a cationic or anionic polymer compound having a viscosity average molecular weight exceeding 35 million. The cationic or anionic charge density of the cationic or anionic polymer compound is 0.6 to 4.0 meq / g.

Here, the viscosity average molecular weight is a viscosity average molecular weight in terms of polyvinyl alcohol measured by an intrinsic viscosity method. Specifically, it refers to a numerical value obtained by measuring and converting the intrinsic viscosity using an Ubbelohde viscometer (trade name “Viscometer Ubbelohde” manufactured by Shibata Kagaku Co., Ltd.).

Also, the cation or anion charge density refers to the equivalent number (meq / g) of cation or anion charge in the monomer unit constituting the polymer compound. Specifically, in the case of a cationic polymer, it refers to a numerical value obtained by colloidal titration using polyvinyl potassium sulfate (manufactured by Wako Pure Chemical Industries, Ltd., trade name “Polyvinyl Potassium Sulfate Titration Solution (N / 400)”). In the case of an anionic polymer, after adding a methyl glycol chitosan solution (trade name “methyl glycol chitosan solution (N / 200)” manufactured by Wako Pure Chemical Industries, Ltd.), excess polyvinyl potassium sulfate (Wako Pure Chemical Industries, Ltd.) The numerical value calculated | required by the colloid titration method using the company make and brand name "Polyvinyl potassium sulfate titrant (N / 400)".

When the viscosity-average molecular weight of the cationic or anionic polymer compound exceeds 35 million, a high fixing power of the papermaking additive for pulp components and fillers can be obtained, and the yield is improved. In particular, if the viscosity average molecular weight is 38 million or more, fine pulp fibers, fillers, and pitch components do not fall off under screen-like shear after floc formation, improving the yield and preventing paper machine contamination. can do. Moreover, if a viscosity average molecular weight is 80 million or less, it will become a favorable cohesion force and the desired physical property of paper can be obtained. Accordingly, the preferred viscosity average molecular weight of the cationic or anionic polymer compound constituting the retention agent of the present invention is in the range of 38 million to 80 million, and the particularly preferred upper limit of the viscosity average molecular weight is 70 million.

Until now, it has been considered that the yield agent will not be uniformly dispersed in the pulp-containing aqueous slurry and the physical properties of the pulp will be lowered if a polymer containing a polymer compound having a molecular weight exceeding 35 million is used as the yield agent. It was. In addition, the conventional retention agent has neutralized the pulp surface charge to fix the filler and various papermaking additive on the pulp surface, but at the same time it contains unnecessary moisture in the floc, In some cases, the flocs become too fine when the shearing is applied, such as passing through the screen or passing through the screen, or the shape becomes uneven. As a result, the physical properties of the texture may be lowered. In the present invention, by setting the charge density of the polymer compound within the range of 0.6 to 4.0 meq / g, the polymer compound is uniformly dispersed in the pulp-containing aqueous slurry, and flocs having a uniform size are obtained. It can be formed and the physical properties of the texture are improved.

In other words, by adjusting the charge density of the polymer compound contained in the yielding agent of the present invention within such a range, the polymer compound having a chain structure has a good cohesive force due to the charge state in the molecule. Thus, since the molecular chain is widened, it is possible to provide a new yield agent that is not a yield improvement effect due to electric charges, unlike the conventional yield agent. Therefore, it can be used regardless of the type of paper obtained, such as acidic paper or neutral paper, and even if the charge density in the pulp-containing aqueous slurry is high, it does not impair the physical properties of the paper and produces paper with a high yield. Can do. If the charge density is 0.6 meq / g or more and 4.0 meq / g or less, the yield, drainage, and physical properties can be improved, and the pitch amount can be reduced. The charge density is preferably in the range of 0.6 meq / g to 3.8 meq / g, particularly preferably 0.8 meq / g to 3.0 meq / g.

The cationic polymer compound contained in the retention agent of the present invention is not particularly limited in its chemical structure as long as the viscosity average molecular weight and the charge density are within the range, and it is linear, branched, or crosslinked. Any of them can be used. In the retention agent of the present invention, one kind of cationic polymer compound may be contained, or two or more kinds may be contained.

Examples of the cationic polymer compound contained in the retention agent of the present invention include, for example, polyethyleneimine, dimethyldiallylamine-sulfur dioxide copolymer, polyacrylamide cation-modified product, polyaminoacrylic acid, and quaternary ammonium salt residues. Homopolymers or copolymers containing a cationic monomer having a structural unit, epihalohydrin-alkylamine addition polymers and allylamine polymer salts or quaternary ammonium salts, and dicyandiamide-formaldehyde-ammonium chloride condensation polymers. In particular, a homopolymer or copolymer containing a cationic monomer having a quaternary ammonium salt residue as a constituent unit is preferable.

Examples of the cationic monomer having a quaternary ammonium salt residue constituting such a cationic polymer compound include 2- (meth) acryloyloxyethyltrimethylammonium chloride and 2- (meth) acryloyloxyethyldimethylbenzyl. Ammonium chloride, 2- (meth) acryloyloxyethyltriethylammonium chloride, 2- (meth) acryloyloxyethyldiethylbenzylammonium chloride, 3- (meth) acrylamidopropyltrimethylammonium chloride, 3- (meth) acrylamidopropyltriethylammonium chloride, 3- (Meth) acrylamidopropyldimethylbenzylammonium chloride, diallyldimethylammonium chloride, diallyldiethylammonium chloride Lolide, 2- (meth) acryloyloxyethyltrimethylammonium sulfate, 2- (meth) acrylamidoethyltrimethylammonium chloride, 2- (meth) acryloyloxyethyltriethylammonium bromide, 3- (meth) acryloyloxypropyldimethylethylammonium chloride, 3-methacryloyloxy-2-hydroxypropyltrimethylammonium chloride, 3-methacryloyloxy-2-hydroxypropylmethyldiethylammonium chloride, 3-methacryloyloxy-2-hydroxypropyltrimethylammonium chloride, 2- (meth) acryloylaminoethyltrimethylammonium Chloride, 3- (meth) acryloylamino-2-hydroxypropyltrimethyla Moniumukurorido, 2- (meth) acryloyl-aminoethyl trimethylammonium chloride and the like. Among these, a homopolymer or copolymer using 2- (meth) acryloyloxyethyltrimethylammonium chloride is preferable because the cationic charge density and the viscosity average molecular weight can be easily adjusted to desired values. The term (meth) acryloyl means acryloyl or methacryloyl.

The cationic polymer compound may be a copolymer of the cationic monomer and a monomer copolymerizable therewith, for example, an ethylenically unsaturated compound. Examples of the ethylenically unsaturated compound constituting the copolymer include ethylenically unsaturated monocarboxylic acids and dicarboxylic acids, (meth) acrylic acid alkyl esters, aromatic vinyl compounds, unsaturated amide compounds, and unsaturated nitriles. Compounds and the like. Examples of such are (meth) acrylic acid, maleic acid, fumaric acid, itaconic acid, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate , Pentyl (meth) acrylate, 2-methylbutyl (meth) acrylate, tert-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, hexyl (meth) acrylate, ( Examples include 2-hydroxyhexyl (meth) acrylate, styrene, α-methylstyrene, (meth) acrylamide, N, N-dimethylacrylamide, N-methylolacrylamide, (meth) acrylonitrile and the like. Among them, (meth) acrylamide, particularly acrylamide is preferable because it is easily available and polymerization is easily performed. The term (meth) acryl means acryl or methacryl.

When the cationic polymer compound is a copolymer, the content of the cationic monomer unit having a quaternary ammonium salt residue in the cationic polymer compound is preferably in the range of 3 mol% or more and less than 40 mol%. If the content of the cationic monomer unit is less than 3 mol%, it is difficult to obtain a desired cationic charge density, and if it is 40 mol% or more, it is difficult to improve the yield of pulp or filler, and the use of a conventional retention agent is used. It is difficult to reduce the amount. A more preferable blending ratio is in the range of 5 to 30 mol%.

The salt of the allylamine polymer is represented by the following general formula [I],

(Wherein R ¹ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, X ¹ is a chlorine atom, bromine atom, sulfuric acid residue, nitric acid residue, organic carboxylic acid residue or organic sulfonic acid residue, n is Represents the degree of polymerization).

In the salt of the allylamine polymer represented by the general formula [I], R ¹ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, preferably a hydrogen atom, a methyl group, an ethyl group, a propyl group, or an isopropyl group. And X ¹ is a chlorine atom, a bromine atom, a sulfuric acid residue, a nitric acid residue, an organic carboxylic acid residue, or an organic sulfonic acid residue. Examples of allylamine polymer salts include polyallylamine hydrochloride, hydrobromide, sulfate, acetate, propionate, poly N-alkylallylamine, polymethylallylamine hydrochloride, poly Examples include ethylallylamine hydrochloride, polypropylallylamine hydrochloride, polyisopropylallylamine hydrobromide, and the like.

The method for polymerizing the cationic polymer compound is not particularly limited, and any method such as a solution polymerization method, an emulsion polymerization method, a solid polymerization method and the like can be used. Examples of the polymerization initiator used here include water-soluble azo compounds and peroxides such as hydrogen peroxide, 2,2′-azobis (2-amidinopropane) dihydrochloride, water-soluble inorganic peroxides, and water-soluble compounds. Combinations of water-soluble inorganic peroxides and organic peroxides.

Examples of water-soluble inorganic peroxides include potassium persulfate and ammonium persulfate. Examples of the water-soluble reducing agent include a reducing agent used as a normal radical redox polymerization catalyst component soluble in water, such as ethylenediaminetetraacetic acid or a sodium salt or potassium salt thereof, and iron, copper, Complex compounds with heavy metals such as chromium, sulfinic acid or its sodium or potassium salt, L-ascorbic acid or its sodium, potassium or calcium salt, ferrous pyrophosphate, ferrous sulfate, ammonium ferrous sulfate Sodium sulfite, acidic sodium sulfite, sodium formaldehyde sulfoxylate and the like.

On the other hand, examples of water-soluble organic peroxides include cumene hydroperoxide, p-cymene hydroperoxide, tert-butylisopropylbenzene hydroperoxide, diisopropylbenzene hydroperoxide, p-menthane hydroperoxide, decalin hydroperoxide, tert-amyl hydro And hydroperoxides such as peroxide, tert-butyl hydroperoxide, and isopropyl hydroperoxide.

In addition, as an emulsifier in this emulsion polymerization, an anionic surfactant or a combination thereof with a nonionic surfactant is usually used. The anionic surfactant or nonionic surfactant can be arbitrarily selected from those used in ordinary emulsion polymerization. Examples of such anionic surfactants include alkyl benzene sulfonate, alkyl sulfonate, alkyl sulfate ester salt, fatty acid metal salt, polyoxyalkyl ether sulfate ester salt, polyoxyethylene carboxylic acid ester sulfate ester salt, Examples thereof include polyoxyethylene alkylphenyl ether sulfate ester salts and succinic acid dialkyl ester sulfonate salts.

Examples of nonionic surfactants include polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkyl ether glycerin borate ester, polyoxyethylene A compound having a polyoxyethylene chain in the molecule, such as ethylene alkyl ether phosphate ester, having surface activity and a compound in which the polyoxyethylene chain of the compound is replaced by a copolymer of oxyethylene and oxypropylene, Examples include sorbitan fatty acid ester, glycerin fatty acid ester, and pentaerythritol fatty acid ester.

When the cationic polymer compound contained in the retention agent of the present invention is synthesized by an emulsion polymerization method, for example, in an aqueous medium containing a polymerization initiator and an emulsifier, the ethylenically unsaturated compound and the cationic monomer are prescribed. By mixing at a ratio and polymerizing at a temperature usually in the range of 30 to 80 ° C., an emulsion in which desired copolymer fine particles are uniformly dispersed can be obtained. The emulsion obtained by this method can be directly blended into a pulp-containing aqueous slurry as a retention agent. If desired, the copolymer is taken out as a solid by salting out or spray drying and the like. You may mix | blend with a turbid liquid. The branched and crosslinked cationic polymers can be produced by using a polyfunctional compound having two or more reagent groups selected from the group consisting of a double bond, an aldehyde bond, and an epoxy bond in each polymerization method described above. A cross-linking agent constituted by a polyfunctional compound having two or more kinds of reagent groups selected from the group consisting of a branching agent or a double bond, an aldehyde bond or an epoxy bond (this cross-linking agent includes a polyvalent metal salt , An ionic cross-linking agent such as formaldehyde and glyoxal, and a covalent cross-linking agent copolymerizing with the monomer).

On the other hand, in the anionic polymer compound contained in the retention agent in the present invention, the chemical structure is not particularly limited as long as the viscosity average molecular weight and the charge density are within the range, and the linear structure, the branched structure, Any cross-linked type can be used. Moreover, the retention agent of this invention may contain 1 type of anionic polymer compounds, and may contain 2 or more types.

Examples of the anionic polymer compound include polymers having a structural unit of a water-soluble monomer containing acrylic acid or methacrylic acid, such as sodium polyacrylate, polysodium methacrylate, and the water-soluble monomer. Copolymers with constituent units copolymerizable therewith, for example, copolymers with constituent units such as acrylamide, methacrylamide, vinyl acetate, acrylonitrile, eg acrylamide-sodium acrylate copolymer, methacrylamide-sodium acrylate copolymer A homopolymer or copolymer containing sodium acrylate as a structural unit as an anionic monomer is particularly preferable.

When the anionic polymer compound is a copolymer, the content of the water-soluble monomer in the anionic polymer compound is preferably in the range of 3 mol% or more and less than 40 mol%. If the content of the water-soluble monomer is less than this range, an effective anionic polymer compound cannot be obtained, and if it exceeds this range, it is not necessary to make a copolymer, which is not preferable. A more preferable blending ratio is in the range of 5 to 30 mol%.

The polymerization method of the anionic polymer compound of the present invention is not particularly limited, and any method such as a solution polymerization method, an emulsion polymerization method, a solid polymerization method, etc., may be used as in the polymerization method of the cationic polymer compound. Can do.

The properties of the retention agent of the present invention are not particularly limited, and examples thereof include water-in-oil emulsions, powders, and solutions.

The retention agent of the present invention is used by being added to the pulp-containing aqueous slurry at least one before passing through the screen and after passing through the screen. It does not restrict | limit especially as said pulp component, What was selected from 1 type, or 2 or more types of pulp chosen from mechanical pulp, chemical pulp, waste paper pulp, etc. can be used. Examples of mechanical pulp include groundwood pulp, refiner ground pulp, and thermomechanical pulp (TMP). Examples of the chemical pulp include kraft pulp such as hardwood kraft pulp (LBKP) and softwood kraft pulp (NBKP), sulfide pulp, alkaline pulp and the like. Examples of the used paper pulp include newspapers, pulp made of corrugated cardboard and shredder dust, and DIP subjected to deinking treatment. Although such a used paper pulp utilization rate tends to increase due to an increase in environmental awareness, virgin pulp can also be used in the present invention. Examples of the raw pulp include coniferous trees such as spruce, todomatsu and red pine, and broad-leaved trees such as beech, poplar and hippopotamus.

In the retention agent of the present invention, the filler is uniformly dispersed in the pulp-containing aqueous slurry and fixed to the pulp component as compared with the conventional retention agent, so that the filler can be suitably used for the pulp-containing aqueous slurry having a high concentration. . The retention agent of the present invention can be suitably used particularly when the amount of filler added to the pulp component is 5 to 60% by mass. The filler is not particularly limited, but calcium carbonate such as heavy calcium carbonate and light calcium carbonate, titanium oxide, silica, talc, clay, kaolin, magnesium carbonate, barium carbonate, zinc oxide, silicon oxide, aluminum hydroxide Inorganic fillers such as calcium hydroxide, magnesium hydroxide, zinc hydroxide, bentonite, and white carbon, and organic fillers such as urea-formalin resin, polystyrene resin, melamine resin, phenol resin, and fine hollow particles. A filler can be used individually or in combination of 2 or more types as appropriate. In addition, recycled fillers made from papermaking sludge, deinking floss, etc. can also be used.

Next, the paper manufacturing method of the present invention will be described. The paper production method of the present invention is a paper production method having a step of making a paper after passing a pulp-containing aqueous slurry through a screen. At least one of the pulp-containing aqueous slurry before and after passing through the screen, the yield agent of the present invention is used. The retention agent of the present invention is added to the pulp-containing aqueous slurry so that the concentration of the cationic or anionic polymer compound contained is less than 500 ppm relative to the pulp component. Such a point is important in the paper manufacturing method of the present invention, and there is no particular limitation other than that. By adding the retention agent of the present invention to the pulp-containing slurry under such an addition condition, the physical properties of the pulp can be maintained without causing the pulp components to overcoagulate. In addition, the density | concentration of the high molecular compound of less than 500 ppm means that the density | concentration of the high molecular compound in the total addition amount of the retention agent added to a pulp containing aqueous slurry is less than 500 ppm with respect to a pulp component.

Hereinafter, the paper manufacturing method of the present invention will be described in detail with reference to the drawings. FIG. 1 is a flowchart showing the addition position of a retention agent in the paper manufacturing method of the present invention. In the paper manufacturing method of the present invention, for example, a concentrated pulp-containing aqueous slurry containing at least 3% by mass of pulp components from the seed box 1 is passed through the fan pump 2 so that the pulp components are about 0.5 to 2.0% by mass. Then, the diluted pulp-containing aqueous slurry is passed through the screen 3 and sent to the inlet 4. The retention agent of the present invention has a diluted pulp-containing aqueous solution so that the concentration of the cationic or anionic polymer compound is less than 500 ppm with respect to the pulp component before and after passing through the screen 3. Add to slurry. Then, after producing the aqueous slurry to which the retention agent is added, paper is manufactured through a dehydration step, a water squeezing step, and a drying step.

In the paper manufacturing method of the present invention, the polymer compound contained in the retention agent must be cationic or anionic in its ionicity, but various components such as filler and pulp contained in the pulp-containing aqueous slurry, this slurry Depending on the physical properties of the polymer, the ionicity of the polymer compound may be appropriately selected.

In the paper manufacturing method of the present invention, the retention rate of the present invention is added to the pulp-containing aqueous slurry before and after passing through the screen 3, and the concentration of the polymer compound is less than 500 ppm relative to the pulp component. However, when making paper with an emphasis on the quality of the obtained paper, that is, the physical properties of the paper, the retention agent is added to the pulp-containing aqueous slurry before passing through the screen 3 so that the concentration of the polymer compound with respect to the pulp component is high. It is preferable to add so as to be less than 500 ppm, preferably 10 to 450 ppm. This is because when a retention agent is added at this position, the physical properties of the resulting paper can be easily controlled. In addition, when making paper with an emphasis on cost, that is, with an emphasis on yield and a reduction in the amount of addition of a retention agent (polymer compound), the retention agent is added to the pulp-containing aqueous slurry after passing through the screen 3 with respect to the pulp component. It is preferable to add such that the concentration of the polymer compound is less than 500 ppm, preferably 10 to 300 ppm. This is because when a yield agent is added at this position, a high yield can be obtained although the addition amount is low. However, in consideration of the balance between the physical properties and the yield, the yield of the present invention is contained so that the total concentration of the polymer compound with respect to the pulp components before and after passing through the screen 3 is less than 500 ppm, preferably 10 to 300 ppm. Addition to the aqueous slurry is advantageous because it keeps the floc having an optimal shape.

When the retention agent of the present invention is added before and after passing through the screen 3, the total amount of the retention agent before and after passing through the screen 3 is adjusted so that the concentration of the polymer compound contained therein is less than 500 ppm. However, the addition ratio of the retention agent of the present invention before passing through the screen 3 and after passing through the screen 3 may be appropriately selected from 99: 1 to 1:99. When the retention agent of the present invention is used before and after passing through the screen 3, the retention agent used before passing through the screen 3 and the retention agent used after passing through the screen 3 may use polymer compounds having different viscosity average molecular weights and charge densities. The ionicity is selected from either cationic or anionic.

The type of paper produced in the paper production method of the present invention is not particularly limited. For example, coated paper, finely coated paper, coated base paper, fine paper, medium quality paper, newspaper, PPC paper, liner base paper , Core base paper, white paperboard and the like.

In the paper manufacturing method of the present invention, conventionally used additives can be used in addition to the retention agent of the present invention. For example, examples of the additive include a sulfuric acid band, a sizing agent, a paper strength agent, a drainage improver, a coagulant, a pitch control agent, a bulking agent, and a slime control agent.

In the paper production method of the present invention, the filler is uniformly dispersed in the pulp-containing aqueous slurry even if the filler is highly blended, so that it has a high yield and good physical properties, and is a polymer compound. Can be produced at a low concentration, that is, with a reduced amount of added additive. That is, pitch trouble can be prevented even when the filler is highly blended in the pulp-containing aqueous slurry using waste paper. Moreover, a high yield effect can be exhibited without being influenced by the environment such as the charge state (cation and anion required amount) of the pulp-containing aqueous slurry. Furthermore, since the work of adding two or more types of retention agents having different ionic properties in combination is not required, the work can be simplified.

Hereinafter, the retention agent of the present invention and the method for producing paper using the same will be described in detail with reference to examples. However, the retention agent of the present invention and the method for producing paper using the same are limited by these examples. Is not to be done.

(Examples 1 to 3, Comparative Examples 1 to 3 and Conventional Examples 1 to 3)
Yield agents were prepared using cationic and anionic polymer compounds shown in Tables 1 to 9 below. The cationic and anionic polymer compounds used in the examples, comparative examples, and conventional examples are as follows.
Cationic polymer compound A: Acrylamide-acryloyloxyethyltrimethylammonium chloride copolymer (linear structure)
Cationic polymer compound B: Acrylamide-acryloyloxyethyltrimethylammonium chloride copolymer (branched structure)
Anionic polymer compound A: Acrylamide-sodium acrylate copolymer (linear structure)
Anionic polymer compound B: Acrylamide-sodium acrylate copolymer (branched structure)

[Measurement of viscosity average molecular weight]
The viscosity average molecular weight of the polymer compound was determined by measuring the intrinsic viscosity using a Ubbelohde viscometer (trade name “Viscometer Ubbelohde” manufactured by Shibata Kagaku Co., Ltd.) according to the intrinsic viscosity method, and converting it to polyvinyl alcohol.

[Measurement of cation and anion charge density]
The charge density of each cationic polymer compound was measured using a potassium potassium sulfate (trade name “Polyvinyl potassium sulfate titrant (N / 400)” manufactured by Wako Pure Chemical Industries, Ltd.) according to a colloid titration method. The charge density of the anionic polymer compound was determined by adding methyl glycol chitosan solution (trade name “Methyl glycol chitosan solution (N / 200)” manufactured by Wako Pure Chemical Industries, Ltd.) according to colloidal titration, and then adding the excess to polyvinyl sulfate. It measured using potassium (the Wako Pure Chemical Industries Ltd. make, brand name "Polyvinyl potassium sulfate titrant (N / 400)".

(Test example)
Using the obtained retention agent, a retention agent addition test was performed according to the following procedure, and evaluation was made for 6 items of retention (total yield and ash retention), drainage, turbidity, cation requirement, and pitch. Furthermore, the physical properties of the paper obtained by papermaking after screen addition were evaluated. These items were evaluated by the following methods. In addition, as a conventional example, a retention test for adding a retention agent was performed in the same manner as in Examples and Comparative Examples using a cationic retention agent and an anionic retention aid.

<Yield agent addition test>
A pulp-containing aqueous slurry having a pulp concentration of 3.2% by mass was diluted with white water to prepare a pulp-containing aqueous slurry having a slurry concentration of 1.0% by mass. White water refers to water that is recycled in the paper manufacturing process. After this pulp-containing aqueous slurry was put into a Brit type dynamic drainage jar tester (equipped with a stirrer equipped with a 40 mesh screen and turbine blades, hereinafter abbreviated as “Brit jar”), each time using a stirrer. While stirring at 1200 rpm, the sulfuric acid band is 0.5% by mass, the alkyl ketene dimer sizing agent (AKD) is 0.2% by mass, and the cationic polyacrylamide paper strength agent is 0.5% at intervals of 10 seconds. Calcium carbonate as a filler was added in this order at a mass% concentration shown in Tables 1 to 9 below, and after 25 seconds, the number of rotations was changed to 600 rotations, and the mixture was further stirred for 15 seconds. The addition position of the retention agent was 10 seconds and / or 25 seconds after the filler was added. The case where the retention agent was added 10 seconds after the addition of the filler was defined as a screen (SC) pre-addition test, and the obtained results are shown in Tables 1 to 3. Further, a case where a retention agent was added 25 seconds after the addition of the filler was regarded as an after-screen addition test, and the obtained results are shown in Tables 4-6. Further, the case where the retention agent was added 10 seconds and 25 seconds after the addition of the filler was taken as the addition test before and after the screen, and the obtained results are shown in Tables 7 to 9. In addition, the pH of the pulp-containing aqueous slurry (hereinafter referred to as “sample slurry”) after the addition of each drug and the retention agent was adjusted to 7.5.

[Yield]
100 ml of the sample solution obtained in the retention agent addition test was transferred to Whatman No. It filtered using 4 filter papers, the obtained filtrate was dried for 60 minutes at 110 degreeC, and the total yield (%) was calculated | required by measuring the mass after drying. Further, the ash content yield (%) was measured from the ash content when the dried filter paper was heated at 550 ° C. for 2 hours.

[Material properties]
The sample slurry obtained in the retention agent addition test was paper-made using a paper machine (trade name “Square Paper Machine” manufactured by Tozai Seiki Co., Ltd.) so that the basis weight was 50 g / m ² . The obtained wet paper was pressurized with a press machine at a load of 5.25 kg / cm ^{2 for} 5 minutes, further pressurized for 2 minutes, and then dehydrated. Subsequently, after drying at 95 ° C. for 3 minutes using a rotary dryer, the paper was left to stand at 25 ° C. and a humidity of 55% for 24 hours to obtain a paper for evaluation. The texture index of the paper was measured using a light transmission type optical total (MK SYSTEMS, trade name “3D sheet analyzer”). The obtained index value indicates that the larger the value, the better the physical properties.

[Drainage]
500 ml of the sample slurry obtained in the retention agent addition test was placed in an acrylic resin cylindrical container having an inner diameter of 50 mm with 100 mesh stretched, and the time until the amount of filtered water reached 200 ml was measured using a graduated cylinder.

[Turbidity]
While stirring the sample slurry obtained in the retention agent addition test with a stirrer, 50 ml was collected from the pilot hole. Suction filtration was performed with 4 filter papers, and the formazine turbidity of the filtrate was measured according to JIS K0101. This turbidity is for evaluating the yield, drug and pitch fixability, and the smaller this value, the higher the yield and the higher the drug and pitch fixability.

[Cation requirement]
As in the turbidity measurement, 50 ml of the sample slurry obtained in the retention agent addition test was collected from the pilot hole while stirring with a stirrer. Suction was filtered through 4 filter papers. The amount of cation required for the obtained filtrate was measured with a particle charge meter (trade name “Particle Charge Detector PCD03” manufactured by Mutech). This cation requirement is for evaluating the charge state in the system. If this value is high, it means that a lot of anionic substances are contained in the system.

[Pitch amount]
250 ml of the sample slurry obtained in the retention agent addition test and a polyethylene foam plastic piece (12 cm × 3 cm × 1 cm) whose mass was measured in advance were placed in a glass bottle, shaken at a constant temperature of 40 ° C. for 2 hours, and then the plastic piece was taken out. , Washed with 100 ml of ion-exchanged water, dried, the mass of the foamed plastic piece was measured, the amount of adhesion (mg) was determined by the following formula, and the amount of adhesion was defined as the pitch amount.
Adhering amount = (mass of plastic piece after shaking)-(mass of initial plastic piece)
This pitch amount indicates the amount of the hydrophobic pitch component in the system. If this value is high, it means that the pitch component cannot be fixed to the pulp fiber.

From Tables 1 to 9, it can be seen that the retention agent of the present invention provides high retention and drainage without impairing the physical properties of the paper even when the amount of filler added is large. For example, the filler content is 20% in Example 1-11, 40% in Example 1-12, and 50% in Example 1-13. As the filler increases, the total yield increases in Example 1-11. Although 76.0%, 72.9% in Example 1-12 and 70.5% in Example 1-13, the charge density is 4.8 meq / g in Comparative Example 1-11. Even when the filler is 20%, the overall yield rate is 69.8%, and it can be seen that the overall yield rate is lower than that of Example 1-13.

When the amount of filler added is large, the pitch amount is generally increased, but 3.15 in Example 1-9, 3.15 in Example 1-12 and 3.26 in Example 1-13. On the other hand, it is 3.46 in Comparative Example 1-11, and it can be seen that the yield of the present invention tends to decrease the pitch amount in the sample slurry. Similarly, when Examples 2-10, 2-12, and 2-13 are compared, the yield rate decreases as the filler increases. In Comparative Example 2-11, the charge density is 5.0 meq / g. Therefore, it can be seen that the yield rate is lower than that of Example 2-13. Further, the pitch amount is 2.92 in Example 2-10, 3.09 in Example 2-12, and 3.18 in Example 2-13, whereas it is 3.2 in Comparative Example 2-11. 34, which indicates that the pitch amount in the sample slurry tends to decrease. As described above, since the yield of the present invention has a small pitch amount, the pitch is fixed to the pulp fiber and discharged out of the sample slurry, and as a result, it is possible to prevent the pitch from adhering to the paper machine.

Moreover, with the retention agent of the present invention, paper having physical properties superior to those of the comparative examples and the conventional examples was obtained regardless of whether the pulp contained in the aqueous slurry was recycled pulp or virgin pulp. Further examination of the types of pulp revealed that Examples 1-1, 1-19, 1-22, 1-23 and 1-24, Examples 2-1, 2-17, 2-18, 2-19 and 2-20, referring to Examples 3-1, 3-11, 3-12, 3-13, 3-14 and 3-15, kraft pulp is the most effective as an effect on the pulp slurry regardless of the addition position of the retention agent. It can be seen that, when the retention agent of the present invention is used, the yield is improved even if the filler content is high, and the pitch amount in the pulp-containing aqueous slurry tends to decrease.

Further, the retention agent of the present invention is different from the conventional example in which a cationic retention agent and an anionic retention aid are used in combination, before and after the screen, that is, before or after shearing. However, a paper having excellent physical properties was obtained without using a plurality of retention agents having different ionic properties. This point is further examined below from the viewpoint of the viscosity average molecular weight and charge density of the cation or anionic polymer compound contained in the retention agent.

(Effect of viscosity average molecular weight)
Considering the case where the addition position of the retention agent is in front of the screen, Examples 1-1, 1-14, 1-15 and 1-16 are all yields, drainage, turbidity compared with Comparative 1-15. It can be understood that the pitch is improved and the pitch is reduced. In Example 1-16, although the overall yield was extremely high, it was a practical level, but the physical properties were slightly inferior. Further, when Example 1-2 and Comparative Example 1-2 are compared, it can be understood that Example 1-2 improves all the physical properties without impairing the physical properties of the texture. When Example 1-5 is compared with Comparative Example 1-7, it can be understood that the physical properties of the texture are also improved.

Next, when considering the case where the addition position of the retention agent is after the screen, Examples 2-1 and 2-14 are not affected by the physical properties as compared with Comparative Example 2-13. It can be understood that the turbidity is improved and the pitch amount is also reduced. This tendency was the same even when Example 2-2 was compared with Comparative Example 2-2.

Further, when considering the case where the addition position of the retention agent is before and after the screen, Examples 3-1 and 3-8 are similar to Comparative Example 3-12 in spite of having the same or higher physical properties. It can be understood that various characteristics are improved. In particular, in the comparison between Example 3-2 and Comparative Example 3-3, it can be confirmed that the retention agent of the present invention is excellent in all physical properties, although the physical properties of the material are greatly improved. From these comparisons, it can also be understood that the influence of the viscosity average molecular weight has an effect larger than the amount of the retention agent added.

Therefore, when the viscosity average molecular weight exceeds 35 million, regardless of the position where the retention agent is added, especially in pulp-containing aqueous slurries containing waste paper pulp, fine pulp fibers, fillers, and pitch under shear like a screen after floc formation It can be seen that since the components do not fall off, contamination of the paper machine can be prevented, and the yield, drainage, and turbidity are improved.

In Comparative Example 3-1, a 150 ppm retention agent was added as a total addition, but the total yield rate was 50.5%, the ash content retention rate was 25.9%, the freeness was 209 seconds, and the turbidity was 27.0 degrees. On the other hand, in Example 3-1, the viscosity average molecular weight is 40 million that satisfies the predetermined range, so that the total yield rate is 57.8% and the ash content yield is reduced despite the addition amount being reduced to 100 ppm. A rate of 33.9%, drainage of 163 seconds, and turbidity of 15.0 degrees were obtained. When the viscosity average molecular weight exceeds 35 million, the amount of the retention agent added can be reduced, and an economic effect can be obtained.

(Effect of charge density)
Consider the case where the yield agent is added in front of the screen. In Examples 1-1, 1-17, and 1-18, when compared with Comparative Examples 1-3 and 1-16, the charge density is in a predetermined range (a range of 0.6 to 4.0 meq / g). In addition, it can be understood that the overall yield rate, drainage, and turbidity are improved and the pitch amount can be further reduced.

This tendency is shown in Examples 1-4 and 1-5, Comparative Example 1-6, Example 1-7, Comparative Example 1-9, Example 1-8, Comparative Example 1-10, and Example 1-10. The same results were observed in Comparative Example 1-12 and in comparison between Example 1-11 and Comparative Example 1-11.

Consider the case where the addition position of the yield agent is after the screen. Examples 2-1, 2-15, and 2-16 are compared with Comparative Examples 2-1 and 2-14 when the charge density is within a predetermined range (range of 0.6 to 4.0 meq / g). It can be understood that the overall yield rate, drainage, and turbidity are improved and the pitch amount is further reduced. This trend is similar to Examples 2-4 and 2-5 and Comparative Example 2-6, Example 2-6 and Comparative Example 2-7, Example 2-9, Comparative Example 2-9 and Example 2-11. The same result was found in comparison with Comparative Example 2-10. In addition, when Example 2-7 and Comparative Example 2-8 are compared, it can also be confirmed that adjusting the charge density has a greater effect on various physical properties than the amount of yield agent added.

Consider the case where the addition position of the yield agent is before and after the screen. In Examples 3-1, 3-9, and 3-10, when compared with Comparative Examples 3-13 and 3-14, the charge density is in a predetermined range (range of 0.6 to 4.0 meq / g). In addition, it can be understood that the total yield rate, drainage, turbidity, and physical properties of the texture are improved and the pitch amount is further reduced. Even when Example 3-4 and Comparative Example 3-7, Example 3-6 and Comparative Example 3-10, and Example 3-7 and Comparative Example 3-11 are respectively compared, excellent effects are obtained for each item. Can be confirmed.

Therefore, the charge density should be adjusted to 4.0 meq / g or less which satisfies the predetermined range (range of 0.6 to 4.0 meq / g) without being affected by the addition position of the yield agent or the amount of waste paper. Can suppress the spread of the chain structure of the polymer compound too much, and the cohesive strength of the desired pulp component can be obtained by the chain structure having an optimal size, so that good yield and drainage can be obtained. It can be seen that the physical properties are improved.

On the other hand, when paying attention to the cation demand, the retention agent of the present invention has obtained excellent results in all physical properties despite a wide range of cation demand, regardless of the charge density in the pulp system, It can be seen that the retention agent of the present invention can be applied.

FIG. 2 is a cross section of the paper obtained in Example 2-11, and the filler (white portion in the drawing) is widely and uniformly dispersed among the stacked pulp components, whereas FIG. FIG. 4 is a cross section of the paper obtained in Example 2-10, where the filler agglomerates to form lumps and is unevenly distributed among the stacked pulp components. Therefore, it can be seen that, when the retention agent of the present invention is used, the filler is uniformly dispersed in the pulp-containing aqueous slurry even when the amount of the filler is high, and the physical properties are improved.

(Example 4 and Comparative Example 4)
Under the same conditions as in Examples 1-10, 1-12, 2-9, 2-12 and 3-5 and Comparative Examples 1-11, 1-12 and 2-9, a paper machine (coating base paper machine, paper machine) Speed: 1300 m / min), a retention agent addition test using an actual machine was performed. In the actual machine, a sulfate band is used in front of the seed box, an alkyl ketene dimer sizing agent (AKD) is used in the seed box, a cationic polyacrylamide paper strength agent is used after the seed box, and calcium carbonate is used as a filler in front of the fan pump. Yield was added before, after the screen or before and after the screen. Table 10 shows the obtained results.

From Table 10, it was found that the retention agent addition test using the Brit-type dynamic drainage jar tester gave the same results as the retention agent addition test using the actual machine.

1 seed box 2 fan pump 3 screen 4 inlet

Claims

A cationic or anionic polymer compound having a viscosity average molecular weight exceeding 35 million,
A retention agent, wherein the cationic or anionic polymer compound has a cation or anion charge density of 0.6 to 4.0 meq / g.
In the method for producing a paper having a step of making a paper after passing the pulp-containing aqueous slurry through a screen,
The yield agent according to claim 1 is added to the pulp-containing aqueous slurry so that the concentration of the polymer compound is less than 500 ppm with respect to the pulp component before passing through the screen and after passing through the screen. Characteristic paper manufacturing method.
The method for producing paper according to claim 2, wherein a filler is further added to the pulp-containing aqueous slurry in an amount of 5 to 60% by mass based on the pulp.
4. The method for producing paper according to claim 2, wherein the yield agent is added to the pulp-containing aqueous slurry after passing through the screen.
4. The paper manufacturing method according to claim 2, wherein the yield agent is added to the pulp-containing aqueous slurry before passing through the screen and the pulp-containing aqueous slurry after passing through the screen.