JP2012031530A - Filler treating agent and paper containing filler treated by the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a filler treating agent capable of manufacturing paper having improved brightness and opacity without reducing paper strength in a manufacturing step of paper and paperboard, and to provide paper containing filler treated with the filler treating agent.SOLUTION: Paper is made by adding a filler treating agent containing a water soluble polymer dispersion comprising one or more fine particles selected from cationic, amphoteric, nonionic and anionic fine particles obtained by dispersion polymerization of vinyl-based water soluble monomer or monomer mixture in a solution containing a kind of water soluble polymer to filler slurry, and mixing the obtained water based filler dispersion in slurry of a papermaking raw material. Consequently, it is possible to manufacture paper having improved brightness and opacity without reducing paper strength, and thus, the problem of the invention can be solved.

Description

The present invention relates to a filler treating agent, and more specifically, cationic and amphoteric substances obtained by dispersing and polymerizing a vinyl-based water-soluble monomer or monomer mixture in an aqueous solution containing one kind of water-soluble polymer. After adding a filler treating agent containing a water-soluble polymer dispersion composed of one or more fine particles selected from nonionic and anionic to the filler slurry, and mixing the aqueous filler dispersion with the pulp slurry, The present invention relates to a filler treating agent capable of producing a paper whose whiteness and opacity are improved without reducing paper strength by making paper, and a paper containing a filler treated with the filler treating agent.

In recent years, paper mills have been demanded to produce lighter weight and low-pulp paper from the viewpoint of environmental protection and cost reduction. However, when the paper is thinned by reducing the basis weight or the pulp amount, there is a problem that the opacity is lowered. In particular, there is a show-through in which the printing can be seen through the opposite surface during printing. Furthermore, the fixing rate of the filler in the papermaking raw material also decreases, and the whiteness tends to decrease. Therefore, there is an increasing demand for maintaining high opacity and high whiteness even when the basis weight and pulp amount are reduced.

In order to improve the opacity and whiteness, a method of increasing the filler content is effective, but at the same time, there is a problem that the paper strength is lowered. In addition, a method for improving the opacity and preventing the back-through by making the paper bulky has also been proposed, but the paper strength of the bulky paper is also reduced because the distance between the fibers is long. There was a problem that. In order to solve these problems, an aqueous filler dispersion with an additive added to the filler is created, and the aqueous filler dispersion is added to the pulp to make paper, thereby improving the pulp fixing of the filler and suppressing strength reduction. How to do is being studied. These additives include cationic semi-natural polymers such as cationized starch and cationized guar gum, cationic synthetic polymers such as polymers of diallylamine salts and diallyldimethylammonium chloride, and styrene as an anionic filler treatment agent. Acrylic polymers, amphoteric polymers and the like have been used. (Patent Documents 1 to 3)

However, the existing filler treatment agents are not sufficient to satisfy all the effects at the same time, although any of the whiteness, opacity and paper strength is improved.

Japanese Patent Laid-Open No. 10-60794 Japanese Patent Laid-Open No. 5-263010 JP 2009-242980 A

The problem to be solved by the present invention is to develop a filler treating agent that can produce paper with improved opacity, whiteness, and paper strength.

One or more selected from cationic, amphoteric, nonionic and anionic obtained by dispersion polymerization of a vinyl-based water-soluble monomer or monomer mixture in an aqueous solution containing one kind of water-soluble polymer A filler treatment agent containing a water-soluble polymer dispersion composed of fine particles is added to a filler slurry, and the aqueous filler dispersion is mixed with a papermaking raw material slurry, and then paper is made. As a result, paper with improved whiteness and opacity can be produced without reducing paper strength, and the problems of the present invention can be solved.

The filler treating agent of the present invention exhibits an effect on various fillers. The filler treating agent containing the water-soluble polymer dispersion of the present invention is produced by dispersion polymerization in a low molecular weight water-soluble polymer having a relatively high cation density. The resulting polymer has a relatively high molecular weight. It contains a polymer with a relatively high cation density and a low molecular weight that serves as a dispersion medium.
This high cation density low molecular weight polymer modifies the surface of the filler and produces fine aggregated particles, and another relatively high molecular weight polymer is converted into moderately sized aggregated particles. Grow. As a result, the aggregated filler particles are uniformly dispersed and adsorbed on the formed paper, so that it is considered possible to improve the whiteness and opacity without reducing the paper strength.

The invention is further described below.

The filler treating agent of the present invention is obtained by dispersing and polymerizing a vinyl-based water-soluble monomer or monomer mixture in an aqueous solution containing at least one of the following water-soluble polymers (A) to (E). It contains a water-soluble polymer dispersion composed of one or more fine particles selected from the obtained cationic, amphoteric, nonionic and anionic.
(A) A polyalkyleneimine sulfate neutralized product.
(B) Neutralized sulfuric acid of polyalkyleneimine modified product.
(C) A mixture of a reaction product and an inorganic salt obtained by reacting one or more amines selected from ammonia, aliphatic monoamines and polyamines with epihalohydrin and / or derivatives thereof.
(D) A mixture of (A) and (B) above, a mixture of (A) and (C) above, or a mixture of (B) and (C) above.
(E) A polymer of a monomer mixture comprising 50 to 100 mol% of a cationic monomer represented by the following general formula (1) and / or (2) and 0 to 50 mol% of a nonionic monomer.
General formula (1)
R ₁ is hydrogen or a methyl group, R ₂ and R ₃ are an alkyl group having 1 to ₃ carbon atoms, an alkoxy group or a benzyl group, and R ₄ is hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkoxy group or a benzyl group. , Same or different. A represents an oxygen atom or NH, B represents an alkylene group or alkoxylene group having 2 to 4 carbon atoms, and X ₁ represents an anion.
General formula (2)
R ₅ represents hydrogen or a methyl group, R ₆ represents hydrogen or an alkyl group having 1 to 3 carbon atoms, R ₇ represents an alkyl group having 1 to 3 carbon atoms, an alkoxy group or a benzyl group, and X ₂ represents an anion.

The water-soluble polymer dispersion composed of one or more fine particles selected from the cationic, amphoteric, nonionic and anionic in one kind of aqueous polymer solution selected from the above (A) to (E) The monomer represented by the general formula (1) and / or (2) is 0 to 100 mol%, the monomer represented by the following general formula (3) is 0 to 50 mol%, and the nonionic monomer is 0. It can be obtained by dispersing and producing a monomer or monomer mixture consisting of ˜100 mol%. These aqueous polymer solutions are used as a kind of dispersion medium in which the above monomers are dispersed and polymerized.
General formula (3)
R ₈ is hydrogen, methyl or carboxymethyl group, Q represents ^{_{SO 3 -, C 6 H 4}} SO 3 -, CONHC (CH 3) 2 CH 2 SO 3 -, C 6 H 4 COO - or ^COO -, _{R 9} Represents hydrogen or COO ^— Y ₂ ⁺ , Y ₁ or Y ₂ represents hydrogen or a cation, respectively.

Examples of the cationic water-soluble monomer represented by the general formulas (1) and (2) include dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth). Tertiary amino group-containing cationic monomers such as acrylamide, diethylaminopropyl (meth) acrylamide and salts thereof, (meth) acryloyloxyethyltrimethylammonium chloride, (meth) acryloyloxyethyldimethylbenzylammonium chloride, (meth) acryloyl Quaternary ammonium such as aminopropyltrimethylammonium chloride, (meth) acryloylaminopropyldimethylbenzylammonium chloride, (meth) acryloyloxy-2-hydroxypropyltrimethylammonium chloride Group-containing cationic monomer, and allylamine, diallylmethylamine and salts thereof, diallyl dimethyl ammonium chloride, and other, include monomers having a cationic group.

Examples of the anionic water-soluble monomer represented by the general formula (3) include (meth) acrylic acid, maleic acid, maleic anhydride, itaconic acid, fumaric acid, crotonic acid, vinyl sulfonic acid, vinyl benzene sulfone. Acid, 2-acrylamido-2-methylpropanesulfonic acid and the like. Among these anionic monomers, one kind or a plurality of kinds may be used. These can use any neutralization state of non-neutralization, partial neutralization, and total neutralization.

The production of the filler treatment agent containing the water-soluble polymer dispersion of the present invention will be described.
The filler treating agent is produced by dispersing and polymerizing a vinyl water-soluble monomer or monomer mixture in an aqueous polymer solution containing any one of the water-soluble polymers (A) to (E). Can be obtained. The polyalkyleneimine represented by the water-soluble polymer (A) is polyethyleneimine or polypropyleneimine. As the polyalkyleneimine modified product represented by the water-soluble polymer (B), for example, polyalkyleneimine modified by crosslinking with epichlorohydrin, ethylene glycol diglycidyl ether or the like can be used. It is preferable to use a polyalkyleneimine modified product having the structural unit represented by 4) or (5). This is synthesized by reacting a polyalkyleneimine or a mixture of polyalkyleneimine and polyamine with a polycationic substance represented by the general formula (6) and / or (7). The polycationic substance can be produced by reacting one or more amines selected from ammonia and aliphatic primary to tertiary amines (hereinafter referred to as primary amines) with epihalohydrin. it can.
General formula (4)

General formula (5)
However, p in the formulas (4) and (5) is an integer of 0 to 20, R10 to R17 are hydrogen, an alkyl group having 1 to 3 carbon atoms, a hydroxyalkyl group or a benzyl group, and X3 to X6 are negative. Ion.
General formula (6)
General formula (7)
However, P in the formulas (6) and (7) is an epoxy group or a halohydrin group, p is an integer of 0 to 20, and R18 to R26 are hydrogen, an alkyl group having 1 to 3 carbon atoms, a hydroxyalkyl group, or benzyl. The groups X7 to X10 are anions.

The molar ratio during the denaturation reaction is in the following range. That is, an amino group in a polyalkyleneimine or a mixture of a polyalkyleneimine and a polyamine is represented by C (mole unit) and a halohydrin group in the polycationic substance represented by the general formula (6) and / or (7). When the epoxy group is D (mole unit), the reaction is carried out in the range of C / D = 5 to 300 (mol%). For example, when the molecular weight of the polyalkyleneimine is as high as several tens of thousands to several hundred thousand, especially when the polycationic substance represented by the general formula (6) is charged at a high ratio, the crosslinking reaction proceeds so much that the polyalkyleneimine becomes It becomes insoluble in water. Therefore, the charged mol% is usually 5 to 50 mol%, preferably 5 to 30 mol%. On the other hand, when the molecular weight of the polyalkyleneimine is as low as 1,000 to 10,000, the charged mol% is usually 50 to 300 mol%, preferably 70 to 150 mol%.

The polycationic substance includes a compound having a crosslinking action having both terminal reactivity represented by the general formula (6) and a compound having a graft reaction function having a one-terminal reactivity represented by the general formula (7). There is. The former having a crosslinking action has a molar ratio of one or more amines selected from ammonia, primary amine, secondary amine, and tertiary amine to epihalohydrin of about 0.25 to 0.9. When the reaction is carried out in the range, the production ratio of the polycationic substance represented by the general formula (6) is high, and those having the latter grafting action are ammonia with respect to epihalohydrin, primary amine, secondary amine, tertiary When the molar ratio of one or more amines selected from amines is reacted in the range of 0.8 to 1.2, the production ratio of the polycationic substance represented by the general formula (7) increases.

The polymerization is generally carried out from neutral to acidic, the monomer is stable, the reactivity is good, the degree of polymerization and the polymerization rate are improved, so the polyalkyleneimine or polyalkyleneimine modified product is It is preferable to neutralize to make a weakly alkaline to acidic aqueous solution. Although it is 12-2 as pH, Preferably it is 10-3, More preferably, it is 6-3. As the acid to be neutralized, an organic or inorganic acid is used. The organic acid is neutralized with formic acid, acetic acid, adipic acid, and the inorganic acid is neutralized with hydrochloric acid, sulfuric acid, sulfamic acid, or the like. As a neutralization degree, it is 50-100 equivalent% with respect to the amino group in a molecule | numerator.

First, a 20 to 50% by mass aqueous solution of polyalkyleneimine or a modified polyalkyleneimine is prepared, and 50 to 100% of the amine equivalent is neutralized with an organic or inorganic acid. The aqueous solution pH at this time is adjusted to 2 to 12, and then the monomer is added to the aqueous solution and mixed. The monomer concentration is 10 to 40% by mass, preferably 15 to 30% by mass. The addition amount of the polyalkyleneimine or the modified polyalkyleneimine to the monomer or monomer mixture before producing the water-soluble polymer dispersion is 20 to 200% by mass, preferably 20 to 150% by mass. More preferably, it is 40-150 mass%.

Thereafter, under a nitrogen atmosphere, a polymerization initiator such as 2,2′-azobis (amidinopropane) dichloride or 2,2′-azobis [2- (5-methyl-2-imidazolin-2-yl) Propane] A water-soluble azo polymerization initiator such as dihydrochloride or a water-soluble redox polymerization initiator such as ammonium persulfate and sodium bisulfite in combination is added, and radical polymerization is carried out with stirring. The polymerization reaction temperature can be arbitrarily selected in the range of 0 to 100 ° C. according to the properties of the polymerization initiator, but is preferably 10 to 60 ° C., more preferably 20 to 50 ° C.

It is presumed that the monomers represented by the general formulas (1) to (3) are graft-polymerized on part of the polyalkyleneimine or the modified polyalkyleneimine. Furthermore, since polyalkyleneimine or polyalkyleneimine modified product has a very branched structure, it is considered that graft polymerization is likely to occur as much, and it is estimated that this greatly contributes to stabilization of the dispersion. It is a very suitable material.

Next, the water-soluble polymer (C) will be described. The water-soluble polymer (C) is a mixture of a reaction product obtained by reacting one or more amines selected from ammonia, aliphatic monoamines and polyamines with epihalohydrin and / or a derivative thereof and an inorganic salt.

There are no particular restrictions on the production method or degree of polymerization of the reaction product of amines and epihalohydrin used, but for example, those synthesized from ammonia, aliphatic alkylmonoamines and epihalohydrins, or synthesized from aliphatic polyamines, alkylenediamines and epihalohydrins. What is done. Examples of the alkyl monoamine include monomethylamine, monoethylamine, dimethylamine, diethylamine, trimethylamine, triethylamine, n-butylamine, and isobutylamine. Examples of alkylene diamines or polyamines include dimethylaminoethylamine, dimethylaminopropylamine, ethylenediamine, diethylenetriamine, triethylenetetramine, pentaethylenehexamine, hexamethylenediamine, and the like. Practically, those synthesized from dimethylamine and epichlorohydrin and those synthesized from aminoethyl-methylamine and epichlorohydrin can be mentioned. Epihalohydrin is epichlorohydrin, epibromohydrin, or the like.

As an actual synthesis method, epihalohydrin can be dropped and reacted with one or more amines selected from ammonia, primary amines of monoamines, secondary amines, and tertiary amines. As an example of the preparation of the reaction, epihalohydrin is charged into a reactor, and one or more amines selected from ammonia, primary amine, secondary amine, and tertiary amine are dropped and reacted. In addition, a polyamine can be added to the reaction product to react with the terminal reaction site of the reaction product to increase the molecular weight. Alternatively, monoamines and polyamines can be mixed from the beginning and reacted with epihalohydrin. At this time, if the reaction is to be in two stages, the epihalohydrin is set to 1 to 1.5 times the equivalent value of the amines, and if the reaction is completed in one stage, the epihalohydrin is from 0.80 to the equivalent value of the amines. It is necessary to devise such as setting to 1.0 times or less.

The molecular weight of the polycondensate produced by the above reaction is 1,000 to 100,000, preferably 3,000 to 50,000, as a weight average molecular weight. Further, the viscosity of the solution is 50% by mass and 50 to 10,000 mPa · s at 25 ° C., preferably 100 to 5,000 mPa · s.

When the dispersion polymerization is performed using the water-soluble polymer (C) as a dispersion medium, the polycondensate and inorganic salts are allowed to coexist. Examples of the salts used include alkali metal halides, sulfates and phosphates. Specifically, sodium chloride, potassium chloride, sodium bromide, ammonium chloride, potassium bromide, ammonium bromide, ammonium sulfate, sodium sulfate, magnesium sulfate, aluminum sulfate, ammonium hydrogen phosphate, sodium hydrogen phosphate, potassium hydrogen phosphate, etc. Although it can illustrate, a sulfate is especially preferable. By allowing the salt to coexist, phase separation between the dispersion medium and the monomer is promoted, the dispersion polymerization is likely to proceed, and the flowability of the produced water-soluble polymer dispersion is improved. However, the present invention is not essentially dispersion polymerization in an aqueous salt solution, but a mixed dispersion of polymer substances that are immiscible with each other. Therefore, even if the salt concentration in the liquid is higher than 20% by mass, a phenomenon such as a decrease in apparent viscosity is not observed. On the other hand, care must be taken since the fluidity of the dispersion may be lowered. Therefore, it is preferable to use the salt concentration in the liquid as 1.0% by mass to 20% by mass, and more preferably 3.0% by mass to 15% by mass.

As a specific production method, first, a reaction product obtained by reacting one or more amines selected from aliphatic monoamines and polyamines with epihalohydrin and / or a derivative thereof, an inorganic salt, and a monomer are necessary. Depending on the situation, a chain transfer compound is mixed. The monomer concentration is 10 to 40% by mass, preferably 15 to 30% by mass. The amount of the reaction product of amines and epihalohydrin added to the monomer mixture before producing the water-soluble polymer dispersion is 50 to 400% by mass, preferably 70 to 300% by mass, more preferably 100%. It is -200 mass%. Moreover, inorganic salt is melt | dissolved so that it may become 1.0 mass%-20 mass% with respect to whole quantity. The polymerization conditions are the same as when the water-soluble polymer (A) or (B) is used as the dispersion medium. These water-soluble polymers (A), (B) and (C) can also be used as a mixture. That is, it is preferable to use the mixture of the above (A) and (B), the above (A) and (C), or the above mixture (B) and (C). These are collectively referred to as a water-soluble polymer (D).

Next, the water-soluble polymer (E) will be described. The water-soluble polymer (E) is a monomer composed of 50 to 100 mol% of a cationic monomer represented by the general formula (1) and / or (2) and 0 to 50 mol% of a nonionic monomer. It is a polymer of a mixture. Examples of the cationic monomer used in producing the water-soluble polymer (D) include the following. That is, examples include dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylamide, methyl diallylamine, and the like. Examples of the quaternary ammonium group-containing monomer include methyl chloride of the tertiary amino-containing monomer. (Meth) acryloyloxyethyltrimethylammonium chloride, (meth) acryloyloxy-2-hydroxypropyltrimethylammonium chloride, (meth) acryloylaminopropyltrimethylammonium chloride, (meth) acryloyloxy, which are quaternized compounds by benzyl chloride Ethyldimethylbenzylammonium chloride, (meth) acryloyloxy-2-hydroxypropyldimethylbenzylammonium chloride, (meth) acryloylaminopropyldimethylbenzylammonium chloride, diary Dimethyl ammonium chloride or the like.

Examples of nonionic monomers include (meth) acrylamide, N, N-dimethylacrylamide, acrylonitrile, (2-hydroxyethyl) (meth) acrylate, diacetone acrylamide, N-vinylpyrrolidone, N-vinylformamide, N-vinylacetamide, acryloylmorpholine, etc. are mentioned.

The water-soluble polymer (E) can be used as an aqueous solution by dissolving polymers in various product forms obtained by known polymerization methods. Moreover, a crosslinkable monomer can be added at the time of superposition | polymerization and a crosslinkable polymer can be used. Specific examples of the crosslinkable monomer include N, N′-methylenebisacrylamide, N, N′-methylenebismethacrylamide, divinylbenzene, N, N-diallylamine, N, N-diallylamine hydrochloride, N, N N-triallylamine, N, N, N-triallylamine hydrohalide, N-methyl-N, N, N-triammonium halide, N-methyl-N, N, N-triallylammonium halide, N, N, Multifunctional monomers having multiple vinyl groups such as N, N-tetraallyl ammonium halide, diallyl fumarate, diallyl maleate, thermally crosslinkable monomers such as N-dimethylacrylamide, and post-crosslinking promotion such as formaldehyde Agents and the like. Among these, when a monomer having a plurality of vinyl groups is used as a crosslinking agent, it can be added during polymerization to carry out a crosslinking reaction in parallel with the polymerization. Of these, N, N'-methylenebisacrylamide is preferably used.

The general formula (1) is a tertiary salt or quaternary ammonium salt such as dialkylaminoalkylene (meth) acrylate or dialkylaminoalkylene (meth) acrylamide, and one or more polymers selected from these monomers. Or it is a copolymer. Further, the general formula (2) is a diallyldialkylammonium salt, which is one or more polymers or copolymers selected from these monomers. A copolymer with a nonionic water-soluble monomer such as acrylamide can also be used. In general, solutions of different polymer compounds are incompatible with each other with little compatibility. The present invention uses this property to carry out dispersion polymerization. Accordingly, when the polymer or copolymer of the monomer represented by the general formula (1) is subjected to dispersion polymerization in an aqueous solution, the general formula (2) is preferably polymerized or copolymerized, and the general formula (2) When the monomer or copolymer represented by general formula (1) is dispersed and polymerized in an aqueous polymer solution, it is preferable to polymerize or copolymerize the monomer represented by the general formula (1).

From the above relationship, when the dispersion polymerization is performed in the polymer of the monomer represented by the general formula (1) of the water-soluble polymer (E) or the copolymer with the nonionic monomer, the copolymerization ratio is It is preferable to use a polymer or copolymer of 100: 0 to 50:50. In this case, the composition of the monomer for dispersion polymerization is preferably such that the copolymerization ratio of the monomer represented by the general formula (2) and the nonionic monomer is 100: 0 to 50:50. By setting this copolymerization ratio, the difference in physical properties between the polymer as a dispersion medium or the copolymer is increased, which is convenient for dispersion polymerization. From the same relationship, when the dispersion polymerization is performed in a polymer of the monomer represented by the general formula (2) or a copolymer with a nonionic monomer, the copolymerization ratio is 100: 0 to 50:50. It is preferable to use a polymer or a copolymer. In this case, the composition of the monomer to be dispersion-polymerized preferably has a copolymerization ratio of the monomer represented by the general formula (1) and the nonionic monomer of 100: 0 to 50:50.

The molecular weight of the water-soluble polymer (E) used as the dispersion medium is 1,000 to 1,000,000, preferably 10,000 to 500,000 as a weight average molecular weight by light scattering. In this case, when expressed in terms of viscosity, it is measured with a B-type viscometer (a type of rotational viscometer) and is 100 to 10,000 mPa · s, preferably 100 to 5,000 mPa · s at a concentration of 20% by mass at 25 ° C. It is.

The amount of the water-soluble polymer (E) added to the monomer mixture before producing the water-soluble polymer dispersion is 50 to 400% by mass, preferably 70 to 300% by mass, more preferably 100 to 100%. 200% by mass. The polymerization conditions are the same as when the water-soluble polymer (A) or (B) is used as the dispersion medium.

In the filler treating agent containing the water-soluble polymer dispersion of the present invention, when producing a cationic water-soluble polymer dispersion, the cationic monomer represented by the general formula (1) and / or (2) One or more of the compounds can be used and copolymerized with nonionic monomers.

Examples of nonionic monomers include (meth) acrylamide, N, N-dimethylacrylamide, vinyl acetate, acrylonitrile, methyl acrylate, 2-hydroxyethyl (meth) acrylate, diacetone acrylamide, N-vinyl pyrrolidone N-vinylformamide, N-vinylacetamide, acryloylmorpholine, acryloylpiperazine, and the like. It is also possible to use a combination of a plurality of these nonionic monomers.

In the case of producing an amphoteric water-soluble polymer dispersion, an anionic monomer represented by the general formula (3) is further copolymerized in addition to the cationic and nonionic monomers.

In the case of producing an anionic water-soluble polymer dispersion, one or more copolymers of the anionic monomer represented by the general formula (3), or the anionic monomer and a nonionic monomer Manufactured by copolymerization with the body.

Furthermore, when manufacturing a nonionic water-soluble polymer dispersion liquid, 1 or more types of the said nonionic monomer are used. A particularly preferred nonionic monomer is acrylamide.

A crosslinkable monomer can be added during the production of the water-soluble polymer dispersion. Specific examples of the crosslinkable monomer include N, N′-methylenebisacrylamide, N, N′-methylenebismethacrylamide, divinylbenzene, N, N-diallylamine, N, N-diallylamine hydrochloride, N, N N-triallylamine, N, N, N-triallylamine hydrohalide, N-methyl-N, N, N-triammonium halide, N-methyl-N, N, N-triallylammonium halide, N, N, Multifunctional monomers having multiple vinyl groups such as N, N-tetraallyl ammonium halide, diallyl fumarate, diallyl maleate, thermally crosslinkable monomers such as N-dimethylacrylamide, and post-crosslinking promotion such as formaldehyde Agents and the like. Among these, when a monomer having a plurality of vinyl groups is used as a crosslinking agent, it can be added during polymerization to carry out a crosslinking reaction in parallel with the polymerization. Of these, N, N'-methylenebisacrylamide is preferably used.

The filler aqueous dispersion is prepared before adding the filler treating agent containing the water-soluble polymer dispersion of the present invention to the papermaking raw material slurry.

In the preparation of the aqueous filler dispersion, the filler slurry is prepared by first charging a powdery filler in water and uniformly dispersing it using a stirrer or the like. Any known method may be used for the dispersion. Thereafter, the filler aqueous dispersion containing the water-soluble polymer dispersion of the present invention is added to the filler dispersion and stirred for a certain time, whereby an aqueous filler dispersion can be prepared.

Any filler that is generally used may be used as the filler. Examples include pulverized natural limestone, precipitated calcium carbonate (PCC), white carbon, clay, calcined clay, kaolin, talc, silica, precipitated silica, aluminosilicate, titanium dioxide and the like, but there is no particular limitation. .

The mixing ratio of the filler treatment agent containing the water-soluble polymer dispersion of the present invention to the filler is not particularly limited, but is preferably 0.01 to 5% by mass in terms of solid content with respect to the filler. More preferably, it is 0.02 to 3% by mass. When the amount of the filler treatment agent is less than 0.01% by mass, the effect may not be sufficiently exhibited. In addition, in the case of 5% by mass or more, depending on the filler used, excessive aggregation may be caused, and the paper texture may be deteriorated, and an opacity improvement effect commensurate with the increase in the amount of the filler treatment agent can be expected. There are cases where it is not possible. The amount of the filler aqueous dispersion obtained by processing in this manner, with respect to the papermaking raw material, varies depending on the concentration of the aqueous filler dispersion, but the dry solid content is 5 to 60% by mass with respect to 100% by mass of the papermaking raw material, Preferably it is 5-30 mass%.

The paper containing the filler treated with the filler treating agent of the present invention can be produced by making a papermaking raw material slurry in which an aqueous filler dispersion is mixed. The place where the filler aqueous dispersion is added is a mixing chest, a seed box, a machine chest, a head box, a tank such as a white water tank, and a pipe connected to these facilities (before and after the fan pump).

In the present invention, a coagulant, a paper strength agent, a drainage improver, a yield improver, a sizing agent, and the like may be used in combination with generally used paper making agents as necessary.

Also, the paper manufacturing method of the present invention can be applied to the manufacture of paper using fillers, such as newsprint paper, book paper, printing / information paper.

Hereinafter, the present invention will be described specifically by way of examples. However, the present invention is not limited to the following examples.

In a reactor equipped with a stirrer, a nitrogen aeration tube, and a temperature control device, 50 g of a 50 wt% polyethyleneimine aqueous solution (weight average molecular weight; 50,000) was dissolved in 21.5 g of ion-exchanged water, and 28.5 g of 75 wt% sulfuric acid was dissolved. The mixture was added with cooling and stirring, and the pH was adjusted to 4.8 to 5.5. This reaction product, that is, neutralized polyethyleneimine, corresponds to the water-soluble polymer (A). A reactor equipped with a stirrer, a nitrogen aeration tube and a temperature controller was charged with 78.0 g of the polyethyleneimine aqueous solution neutralized by the above-mentioned operation, and 48.8 g of 80% aqueous solution of acryloyloxyethyltrimethylammonium chloride and 63.2 g of ion-exchanged water were added. Charged and mixed. While substituting with nitrogen, 500 ppm by weight of a 2,2-azobis (N, N-dimethyleneisobutylamidine) dihydrochloride aqueous solution of 10% by weight as a polymerization initiator was added per monomer, and polymerization was carried out at 36 ° C. for 18 hours with stirring. did. As a result, a water-soluble polymer dispersion of fine particles was obtained. The obtained water-soluble polymer dispersion is designated as trial production-1.

Into a four-necked separable flask equipped with a thermometer, a stirrer, and a dropping funnel was charged 146.6 g of epichlorohydrin and 29.6 g of ion-exchanged water, and 40 to 45 of 123.8 g of a 50% by weight aqueous solution of dimethylamine. The mixture was added dropwise at 2 ° C. over 2 hours, and after completion of the addition, after reacting at 45 ° C. for 1 hour, 29.6 g of ion-exchanged water was added to obtain a polycation product.

Next, in a separable flask equipped with a thermometer and a stirrer, 23.3 g of polyethyleneimine (weight average molecular weight; 10,000), 100% product and 60.0 g of ion-exchanged water were added and stirred, and then the polycation was produced. 26.9 g of the product was added and reacted at 28 ° C. for 45 minutes. When an increase in the viscosity of the reaction product was observed, 4.5 g of 75% sulfuric acid was added to stop the reaction to obtain a polyethyleneimine modified product. The weight average molecular weight was measured to be 50,000.

Next, 109 g of the polyethyleneimine modified product prepared above was collected in a reactor equipped with a stirrer and a temperature control device, and the solution pH was neutralized to 5.5 with sulfuric acid. This reaction product corresponds to the water-soluble polymer (B). To this, 48.8 g of 80% aqueous solution of methacryloyloxyethyltrimethylammonium chloride and 63.2 g of ion-exchanged water were charged and mixed. While replacing with nitrogen, 10 ppm by weight of 2,2-azobis (N, N-dimethyleneisobutylamidine) dihydrochloride aqueous solution as a polymerization initiator was added at 500 ppm by weight per monomer and polymerized at 36 ° C. for 18 hours with stirring. did. As a result, a polymer dispersion of fine particles was obtained. This water-soluble polymer dispersion obtained is designated as trial production-2.

Into a four-necked separable flask equipped with a thermometer, a stirrer, and a dropping funnel was charged 146.6 g of epichlorohydrin and 29.6 g of ion-exchanged water, and 40 to 45 of 123.8 g of a 50% by weight aqueous solution of dimethylamine. The solution was added dropwise at 2 ° C. over 2 hours. After the completion of the addition, after reacting at 45 ° C. for 1 hour, 147.0 g of ion-exchanged water was added to make the concentration of the reaction product 50% by mass. The viscosity of this reaction product at 25 ° C. was 1150 mPa · s.

Next, 12 g of ammonium sulfate was charged into 180 g of a 50 mass% aqueous solution of the above (dimethylamine / epichlorohydrin) reaction product in a reactor equipped with a stirrer, a nitrogen aeration tube, and a temperature controller. This corresponds to the water-soluble polymer (C). Next, 75.0 g of an 80% aqueous solution of acryloyloxyethyltrimethylammonium chloride, 1.2 g of sodium methacryl sulfonate, and 31.8 g of ion-exchanged water were charged and mixed. While substituting with nitrogen, an aqueous 2,2-azobis (N, N-dimethyleneisobutylamidine) dihydrochloride aqueous solution is added as a polymerization initiator at 400 ppm by weight per monomer (1.2 g in a 2% aqueous solution). Polymerization was carried out at 36 ° C. for 18 hours with stirring. As a result, a water-soluble polymer dispersion of fine particles was obtained. This water-soluble polymer dispersion obtained is designated as trial production-3.

A reactor equipped with a stirrer, a nitrogen aeration tube, and a temperature controller was charged with 111.5 g of a 35 mass% polydiallyldimethylammonium chloride aqueous solution. Polydiallyldimethylammonium chloride corresponds to the water-soluble polymer (D). To this, 48.8 g of an 80% aqueous solution of acryloyloxyethyltrimethylammonium chloride and 63.2 g of ion-exchanged water were charged and mixed. While replacing with nitrogen, 10 ppm by weight of 2,2-azobis (N, N-dimethyleneisobutylamidine) dihydrochloride aqueous solution as a polymerization initiator was added at 500 ppm by weight per monomer and polymerized at 36 ° C. for 18 hours with stirring. did. As a result, a water-soluble polymer dispersion of fine particles was obtained. This water-soluble polymer dispersion thus obtained is referred to as trial production-4.

Calcium carbonate was used as a filler, diluted with water to a concentration of 10% by mass, and stirred sufficiently until the calcium carbonate was dispersed to obtain a filler slurry. To this, 0.3% by mass of the water-soluble polymer dispersion of the present invention, that is, prototypes 1 to 4 of Example 1, is added to the dry solid content of the filler slurry, and 10 minutes at 400 rpm with a magnetic stirrer. Stir to prepare an aqueous filler dispersion. Each filler aqueous dispersion was made into prescription -1-4. Next, LBKP having a Canadian Standard Freeness (C.S.F.) value of 410 mL was adjusted to a concentration of 0.5 mass% to obtain a pulp slurry. This pulp slurry was collected so that the sheet basis weight after papermaking was 64 g / m ² , and the filler aqueous dispersion treated with a water-soluble polymer dispersion, Formulations 1 to 4, were purely 25 mass with respect to the pulp. % Was added. These were made with a 1/16 m ² TAPPI standard paper machine to obtain wet paper. The wet paper was pressed at 3.0 kg / m ² for 5 minutes and then dried at 105 ° C. for 3 minutes using a mirror dryer. The dried paper was conditioned at 23 ° C. and 50% RH for 1 day, and the basis weight (g / m ² ) and thickness (mm) were measured (JIS paper thickness gauge TM- 600), the density of the paper was determined by basis weight / thickness. The ash content in the paper was measured by ashing at 525 ° C. Also, using another part of the same paper, ISO whiteness (JIS, P8148; 2001), opacity (JIS, P8149; 2000), internal by spectrophotometer type colorimeter (Technidyne, color touch PC) The bond strength (JAPAN-TAPPI-No. 18-1: 2000) was measured using Tensilon-RTC-1210A manufactured by Orientec Co., Ltd., a transfer rate of 20 mm / min. It was measured by. The results are shown in Table 1.

(Comparative example 1) Calcium carbonate was diluted with water so that it might become 10 mass%, and was fully stirred until calcium carbonate disperse | distributed, and it was set as the filler slurry. A comparative sample (commercially available coagulant, polymethacryloyloxyethyltrimethylammonium chloride, weight average molecular weight 500,000) was added at 0.3% to the dry solid content of the filler slurry, and 400 rpm with a magnetic stirrer. The mixture was stirred for 10 minutes to prepare an aqueous filler dispersion. This aqueous filler dispersion was designated Formula-5. Next, using the same pulp slurry as in Example 5, a filler aqueous dispersion, Formulation-5, was collected so that the sheet basis weight after papermaking was 64 g / m ² and treated with a water-soluble polymer dispersion. A pure content of 25% by mass was added to the pulp. Paper making was carried out with a 1/16 m ² TAPPI standard paper machine under the same conditions and operations as in Example 5, and the paper density, ash content, ISO whiteness, opacity, and internal bond strength were measured. The results are shown in Table 1.

(Comparative example 2) Calcium carbonate was diluted with water so that it might become 10 mass%, and it stirred sufficiently until calcium carbonate disperse | distributed, and this filler slurry was set as prescription-6. Next, paper was made with a 1/16 m ² TAPPI standard paper machine under the same conditions and operations as in Example 5, and the paper density, ash content, ISO whiteness, opacity, and internal bond strength were measured. The results are shown in Table 1.

(table 1)

In the case where the water-soluble polymer dispersion prototypes -1 to 4 of the present invention of Example 5 were added to the filler, the ISO whiteness, opacity, and internal bond strength were all improved with respect to no addition of Comparative Example 2. It was. On the other hand, when the comparative sample of Comparative Example 1 was added, the opacity improved, but the ISO whiteness and internal bond strength decreased. This is because when the water-soluble polymer dispersion prototypes -1 to 4 of the present invention are added, the distribution state of the filler in the pulp and the degree of aggregation are different compared to the case where the comparative sample is added. Both are considered to have improved. In particular, when the comparative sample is added, it is considered that the internal bond strength is reduced because the binding between the pulp fibers is more inhibited than when the prototypes 1 to 4 are added. It was confirmed that by adding the water-soluble polymer dispersion prototypes -1 to 4 of the present invention to the filler and making paper, a paper with improved whiteness and opacity can be produced without reducing paper strength.

Claims (4)

Cationic, amphoteric, nonionic obtained by dispersion polymerization of a vinyl water-soluble monomer or monomer mixture in an aqueous solution containing any one of the following water-soluble polymers (A) to (D) A filler treating agent comprising a water-soluble polymer dispersion composed of one or more fine particles selected from water-soluble and anionic.
(A) A polyalkyleneimine sulfate neutralized product.
(B) Neutralized sulfuric acid of polyalkyleneimine modified product.
(C) A mixture of a reaction product and an inorganic salt obtained by reacting one or more amines selected from ammonia, aliphatic monoamines and polyamines with epihalohydrin and / or derivatives thereof.
(D) The mixture of (A) and (B) above, the mixture of (A) and (C) above, or the mixture of (B) and (C) above (E) The following general formulas (1) and / or (2) The polymer of the monomer mixture which consists of 50-100 mol% of the cationic monomers represented by this, and 0-50 mol% of nonionic monomers.
General formula (1)
R ₁ is hydrogen or a methyl group, R ₂ and R ₃ are an alkyl group having 1 to ₃ carbon atoms, an alkoxy group or a benzyl group, and R ₄ is hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkoxy group or a benzyl group. , Same or different. A represents an oxygen atom or NH, B represents an alkylene group or alkoxylene group having 2 to 4 carbon atoms, and X ₁ represents an anion.
General formula (2)
R ₅ represents hydrogen or a methyl group, R ₆ represents hydrogen or an alkyl group having 1 to 3 carbon atoms, R ₇ represents an alkyl group having 1 to 3 carbon atoms, an alkoxy group or a benzyl group, and X ₂ represents an anion. The water-soluble polymer dispersion composed of one or more fine particles selected from the cationic, amphoteric, nonionic and anionic types is a monomer 0 represented by the general formula (1) and / or (2). ˜100 mol%, produced by dispersion polymerization of a monomer mixture comprising 0 to 50 mol% of a monomer represented by the following general formula (3) and 0 to 100 mol% of a nonionic monomer The filler treating agent according to claim 1, wherein:
General formula (3)
R ₈ is hydrogen, methyl or carboxymethyl group, Q represents ^{_{SO 3 -, C 6 H 4}} SO 3 -, CONHC (CH 3) 2 CH 2 SO 3 -, C 6 H 4 COO - or ^COO -, _{R 9} Represents hydrogen or COO ^— Y ₂ ⁺ , Y ₁ or Y ₂ represents hydrogen or a cation, respectively. An aqueous filler dispersion containing the filler treating agent according to claim 1 or 2. A paper containing a filler treated with the filler treating agent according to claim 1 or 2.