JP2012007283A - Papermaking surface sizing agent, surface sizing coating liquid and paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a papermaking surface sizing agent and a surface sizing coating liquid with which good sizing effect can be obtained, the decrease of frictional coefficient is suppressed and the agglomerate generated during coating on paper can be reduced, and to further provide a paper with excellent sizing effect.SOLUTION: A papermaking surface sizing agent of aqueous emulsion type is used which includes polymer (C) obtained by polymerization of vinyl monomer (A) including hydrophobic monomer (a1) in the presence of cationic water soluble polymer (B), a water soluble aluminium compound (D) and alkyl ketene dimer and/or alkenyl ketene dimer (E).

Description

The present invention relates to a paper size sizing agent, a surface size coating solution, and paper.

The paper sizing surface sizing agent is a sizing agent applied to the surface of paper, and can efficiently impart a sizing effect. As the paper sizing agent, an alkyl ketene dimer or alkenyl ketene dimer (both are collectively referred to as AKD hereinafter) dispersed in water, a polymer having a cationic functional group dispersed in water, or the like is used. It has been.

The AKD surface sizing agent in which AKD is dispersed in water has a good size effect, but has a problem that it takes time to develop the size effect. In addition, when an AKD surface sizing agent is used, the friction coefficient of paper is reduced, so that there is a problem that applications are limited. Furthermore, since the AKD surface sizing agent has a problem in stability with respect to mechanical share, an agglomerate is generated at the time of application to paper, and this agglomerate becomes dirty and adversely affects paper production. It was. Thus, an AKD surface sizing agent using a specific copolymer has been proposed in order to solve the problem with respect to mechanical share. However, it cannot be said that the surface sizing agent has sufficient stability with respect to the mechanical share, and the decrease in the friction coefficient could not be sufficiently suppressed.

Further, as a method for suppressing a decrease in the friction coefficient, a surface sizing agent that is used in combination with a water-soluble polymer compound after controlling the zeta potential within a specific range has been proposed. (Refer to Patent Document 2) According to this method, although the reduction of the friction coefficient can be improved, there is a problem that the size effect is deteriorated by addition of the water-soluble polymer compound.

JP-A-11-217795 JP 2003-221895 A

  The present invention provides a paper size sizing agent, a surface size coating liquid, which has a good size effect and can suppress agglomerates generated during coating on paper, in which a reduction in friction coefficient is suppressed, The object is to provide an excellent paper.

  As a result of intensive studies to solve the above problems, the present inventor has found that the above problems can be solved by using a specific polymer, a water-soluble aluminum compound, an alkyl ketene dimer and / or an alkenyl ketene dimer.

  That is, the present invention relates to a polymer (C) obtained by polymerizing a vinyl monomer (A) containing a hydrophobic monomer (a1) in the presence of a cationic water-soluble polymer (B), a water-soluble aluminum compound. (D) and an aqueous emulsion type paper surface sizing agent containing an alkyl ketene dimer and / or alkenyl ketene dimer (E); the paper sizing surface sizing agent and starches (F), a paper sizing surface sizing agent: starch Surface size coating solution formulated so that the weight ratio (F) is 0.1-20: 99.9-80 (solid content conversion); the paper surface sizing agent or the surface size coating solution It is related with the paper obtained by coating.

  According to the present invention, it is possible to provide a paper sizing surface sizing agent that has a good size effect and that can reduce agglomerates generated during coating on paper, in which a reduction in friction coefficient is suppressed.

  In the present invention, a vinyl monomer (A) (hereinafter referred to as component (A)) containing a hydrophobic monomer (a1) (hereinafter referred to as component (a1)) is converted into a cationic water-soluble polymer (B) (hereinafter referred to as component (A)). B)) and polymer (C) (hereinafter referred to as component (C)), water-soluble aluminum compound (D) (hereinafter referred to as component (D)), alkyl ketene dimer obtained by polymerization in the presence of And / or an aqueous emulsion type papermaking surface sizing agent containing alkenyl ketene dimer (E) (hereinafter referred to as component (E)).

  The component (A) contains the component (a1). As a component (a1), if it is a hydrophobic radically polymerizable monomer, it will not specifically limit, A well-known thing can be used. In particular, it is preferable to use a radically polymerizable monomer having a solubility in water (20 ° C.) of 2% or less. Examples of the component (a1) include styrenes, α-olefins, vinyl esters, N-alkyl (meth) acrylamides, (meth) acrylonitrile, (meth) acrylic esters, dialkyl esters of maleic acid, and And dialkyl esters of fumaric acid.

Examples of styrenes include styrene, α-methylstyrene, vinyltoluene, t-butylstyrene, dimethylstyrene, acetoxystyrene, hydroxystyrene, chlorovinyltoluene and the like.

Examples of α-olefins include 2,4,4-trimethyl-1-pentene, 3-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexene, -Octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicocene, 1-tetracocene, 1-triacontene and the like.

Examples of vinyl esters include vinyl t-carboxylate having 5 to 10 carbon atoms, vinyl propionate, and vinyl acetate.

Examples of N-alkyl (meth) acrylamides include N, N-dimethyl (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, and Nt. -Butyl (meth) acrylamide, N-lauryl (meth) acrylamide, N, N-diisopropyl (meth) acrylamide, N, N-di-t-butyl (meth) acrylamide, N, N-dilauryl (meth) acrylamide, N , N-di-t-octyl (meth) acrylamide, N, N-dicyclohexyl (meth) acrylamide and the like.

Examples of the (meth) acrylic acid alkyl ester include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, normal butyl (meth) acrylate, isobutyl (meth) acrylate, (meth ) T-butyl acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, and the like.

These may be used alone or in combination of two or more. Among these, styrene, normal butyl (meth) acrylate, isobutyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate are preferably used from the viewpoints of size effect and emulsion stability.

The component (A) may contain other radical polymerizable monomer (a2) (hereinafter referred to as the component (a2)) copolymerized with the component (a1) as necessary. (A2) It does not specifically limit as a component, A well-known thing can be used. Specifically, for example, (meth) acrylamide, a hydrophilic monomer having a hydroxyl group, (meth) acrylic acid dialkylaminoalkyl ester, (meth) acrylic acid dialkylaminoalkylamide, (meth) acrylic acid, itaconic acid, ( Examples include sodium (meth) allylsulfonate and glycidyl (meth) acrylate.

Examples of the hydrophilic monomer having a hydroxyl group include hydroxyethyl (meth) acrylate, hydroxymethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, and (meth) allyl alcohol. It is done.

Examples of (meth) acrylic acid dialkylaminoalkyl esters include dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, dimethylaminobutyl (meth) acrylate, and dipropylaminoethyl (meth). Examples thereof include acrylate and dibutylaminoethyl (meth) acrylate.

(Meth) acrylic acid dialkylaminoalkylamides include dimethylaminoethyl (meth) acrylamide, diethylaminoethyl (meth) acrylamide, dimethylaminopropyl (meth) acrylamide, dimethylaminobutyl (meth) acrylamide, and dipropylaminoethyl (meth). Examples include acrylamide and dibutylaminoethyl (meth) acrylamide.

Although content of the component (a1) in a component (A) is not specifically limited, Usually, about 80 to 100 weight% is preferable from a size effect becoming favorable. Moreover, it is preferable that content of the component (a2) in a component (A) shall be about 10 weight% or less.

A component (B) will not be specifically limited if it is a water-soluble polymer which has a cationic functional group, A well-known thing can be used. Specifically, for example, cationized starch, a water-soluble polymer obtained by radical polymerization of a monomer component containing a cationic monomer, cationized polyvinyl alcohol, or the like can be used. Among these, it is preferable to use a water-soluble polymer obtained by radical polymerization of a monomer component containing a cationic monomer. In particular, hydrophobic monomer (b1) (hereinafter referred to as component (b1)) and (meth) acrylic acid dialkylaminoalkyl ester (b2) (hereinafter referred to as component (b2)) and / or (meth) acrylic acid dialkylaminoalkyl It is preferable to use a cationic polymer obtained by copolymerizing amide (b3) (hereinafter referred to as component (b3)) from the viewpoint of dispersion stability and size effect of component (C).

As the component (b1), the same components as the component (a1) can be used.

Examples of the component (b2) include N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-dimethylamino. Examples include butyl (meth) acrylate, N, N-dipropylaminoethyl (meth) acrylate, and N, N-dibutylaminoethyl (meth) acrylate.

Examples of the component (b3) include N, N-dimethylaminoethyl (meth) acrylamide, N, N-diethylaminoethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N, N-dimethylamino. Examples thereof include butyl (meth) acrylamide, N, N-dipropylaminoethyl (meth) acrylamide, N, N-dibutylaminoethyl (meth) acrylamide and the like.

These may be used alone or in combination of two or more. In addition, for the preparation of the component (B), if necessary, another radical polymerization component (b4) (hereinafter referred to as component (b4)) copolymerizable with the components (b1) to (b3) is used in combination. You can also. Examples of component (b4) include sulfonic acid group-containing monomers such as (meth) acrylic acid, (meth) acrylamide, and sodium styrenesulfonate.

Although the usage-amount of a component (b1)-a component (b3) is not specifically limited, Usually, it is set as (b1): [(b2) + (b3)] = 20-90: 80-10 weight% about a component ( The dispersion stability and size effect of C) are preferable. In addition, when using a component (b4), it is preferable that the usage-amount is normally 10 weight% or less of the total amount of a component (b1)-a component (b4).

  The component (B) can be obtained by polymerizing the polymerizable component. The polymerization method is not particularly limited, and a known method can be adopted. When employing solution polymerization, aromatic solvents such as benzene and toluene, lower ketones such as acetone and methyl ethyl ketone, alcohols such as n-propyl alcohol and isopropyl alcohol, and the like can be used as a solvent. The type of the polymerization initiator is not particularly limited, and known ones can be used. For example, 2,2′-azobisisobutyronitrile, 2,2′-azobis-2,4-methylvaleronitrile, etc. Azo compounds, organic peroxides such as benzoyl peroxide, cumene hydroperoxide, tert-butyl hydroperoxide, dicumyl peroxide, lauryl peroxide, and other redox catalyst type compounds can be used. . In the polymerization, chain transfer agents such as α-methylstyrene dimer, mercaptans and secondary alcohols can be used. As conditions for the polymerization reaction, the reaction temperature is usually about 70 to 140 ° C. and the reaction time is about 1 to 10 hours.

  The molecular weight of the component (B) thus obtained is not particularly limited, but usually the weight average molecular weight (polystyrene conversion value by gel permeation chromatography) is about 5,000 to 40,000. This is preferable because the dispersion stability and size effect of the component (C) are improved. In addition, quaternization of a part or all of the amino groups derived from the component (b2) and the component (b3) of the component (B) increases the cationic property of the copolymer, and the formation and size of a stable emulsion. It is preferable because the performance can be improved. The degree of quaternization is preferably at least about 10 mol% of the amino group of component (b2) and / or component (b3) present in the copolymer of component (B), preferably about 50 to 100 mol%. It is more preferable. As the quaternizing agent used for quaternization, known ones can be used. Typical examples include benzyl chloride, methyl chloride, dimethyl sulfate, glycidol, ethylene chlorohydrin, allyl chloride, styrene oxide, propylene oxide, and epichlorohydrin. Quaternization may be carried out usually by incubating at 50 to 90 ° C. for 1 to 4 hours. In addition, although quaternization is normally performed after preparation of a component (B), you may carry out before superposition | polymerization.

Component (C) used in the present invention is obtained by polymerizing component (A) in the presence of component (B). The polymerization method of component (A) is not particularly limited, and a known method can be employed. As the polymerization method, it is preferable to use an emulsion polymerization method because the stability of the obtained component (C) becomes good.

In the case of emulsion polymerization, since component (B) has a function as an emulsifier, other emulsifiers may not be used, but known emulsifiers may be used in combination. As other emulsifiers, cationic surfactants, nonionic surfactants, and the like can be used. As the cationic surfactant, for example, dodecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, octadecyltrimethylammonium chloride, tetradecyldimethylbenzylammonium chloride, octadecyldimethylbenzylammonium chloride and the like can be used. These can be obtained, for example, as Kachiogen H, Kachiogen L manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Cotamin 24P, Cotamin 86P Conch, Cotamin 60W, Cotamin 86W manufactured by Kao Corporation. Nonionic surfactants include, for example, polyethylene glycol, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene styryl phenyl ether, polyoxyethylene sorbitan fatty acid ester, and reactive functional groups in the molecule. A nonionic surfactant having a group can also be used, and one kind can be used alone, or two or more kinds can be used.

The polymerization initiator used for the emulsion polymerization is not particularly limited, and a known one may be used. As the polymerization initiator, for example, any of persulfates such as potassium persulfate and ammonium persulfate, water-soluble azo compounds, and other redox catalyst type may be used. In the polymerization, chain transfer agents such as α-methylstyrene dimer, mercaptans and secondary alcohols can be used. In addition, a crosslinking agent can be used, and methylene bis (meth) acrylamide, ethylene bis (meth) acrylamide, triallyl isocyanurate, triallylamine, tetramethylol methane tetraacrylate, tetra tetrafunctional monomers having 2 to 4 functionalities. Allyl pyromellitate and the like can be used. The emulsion polymerization is usually performed at about 70 to 100 ° C. and the reaction time is about 1 to 10 hours.

In addition, although the usage-amount of a component (A) and a component (B) is not specifically limited, Usually, it is a weight ratio (solid content conversion), and a component (A): component (B) = 1: 4-4: 1 grade. It is preferable that the component (C) has stability and size effects.

The component (C) thus obtained is usually composed of a polymer of the component (A) and the component (B). Although the molecular weight of a component (C) is not specifically limited, Usually, when a weight average molecular weight (polystyrene conversion value by a gel permeation chromatography) shall be about 50,000-500,000, since a size effect will become favorable. preferable.

  As a component (D) used for this invention, it does not specifically limit but a well-known thing can be used. Specifically, for example, aluminum sulfates such as aluminum sulfate, basic aluminum sulfate, and aluminum sulfate oxalate, aluminum chlorides such as aluminum chloride and basic aluminum chloride, aluminum nitrate, and polymers thereof may be used. it can. Among these, it is preferable to use aluminum sulfate because the size effect is good.

As a component (E) used for this invention, it does not specifically limit but a well-known thing can be used. As the component (E), for example, the general formula (1):

(In the formula, R ¹ and R ² are a C8-C30 saturated hydrocarbon group or a C8-C30 unsaturated hydrocarbon group, and R ¹ and R ² may be the same or different.) Can be used. In the general formula (1), the hydrocarbon group of R ¹ or R ² is, for example, an alkyl group such as octyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, eicosyl, octenyl, decenyl, dodecenyl, tetradecenyl, hexadecenyl, octadecenyl, An alkenyl group such as eicosenyl, a substituted phenyl group such as octylphenyl, nonylphenyl, and dodecylphenyl; a substituted cycloalkyl group such as nonylcyclohexyl; and an aralkyl group such as phenylethyl. Among these, a C10 to C25 saturated hydrocarbon group and a C10 to C25 unsaturated hydrocarbon group are preferable, and a C14 to C22 saturated hydrocarbon group and a C14 to C22 unsaturated hydrocarbon group are particularly preferable. R ¹ and R ² are not limited to linear hydrocarbons, and may be branched or cyclic. Examples of such component (E) include octadecyl ketene dimer, hexadecyl ketene dimer, tetradecyl ketene dimer, dodecyl ketene dimer and the like. The ketene dimer may be a dimerized mixture of different fatty acids. Component (E) can be emulsified by a known method and mixed with component (C) and component (D) as an emulsion. In emulsification, for example, cationized starch and sodium lignin sulfonate or naphthalene sulfonate formalin condensate can be used as an emulsifying dispersant. The emulsification method of component (E) is not particularly limited, but forced emulsification using a high-pressure homogenizer is preferable.

Although the usage-amount of a component (C) -component (E) is not specifically limited, Usually, the content of a component (E) is about 5 to 40 weight%, and the total amount of a component (C) and a component (D) is 95. It is preferable to be about ˜60% by weight because the surface sizing agent obtained has good stability and size effect. Moreover, the component (C) and the component (D) were mixed with the component (E) by setting the content ratio (solid content weight ratio) to about (C) / (D) = 20/80 to 80/20. This is preferable because the stability and the size effect are improved.

In addition, the sizing agent for papermaking of the present invention may be emulsified by a known method after mixing the component (C), the component (D) and the component (E). The component (C) and the component (D) You may mix the aqueous solution of this, and the emulsion of a component (E). The order of mixing is not particularly limited.

The surface size coating liquid of the present invention comprises the above paper sizing agent and starches (F) (hereinafter referred to as component (F)) in a weight ratio of about 0.1-20: 99.9-80 (solid It is obtained by blending so as to be (minute conversion).

As a component (F), well-known things, such as oxidized starch, phosphate esterified starch, enzyme modified starch, APS modified starch, cationized starch, and amphoteric starch, are not specifically limited but can be used.

In addition, you may add various well-known additives to the surface size coating liquid of this invention as needed. Examples of the additive include an antifoaming agent, an antiskid agent, an antiseptic, a rust inhibitor, a thickener, a pH adjuster, an antioxidant, a film increasing aid, a pigment, and a dye.

By applying the surface sizing agent for papermaking and the surface size coating liquid of the present invention to a known paper, a paper excellent in size effect can be obtained. The paper sizing agent of the present invention and the paper to which the surface sizing coating solution is applied include various types of paper such as newspaper winding paper, writing paper, wallpaper, PPC paper, inkjet paper, printing paper, and paperboard such as a liner and a core. Can be mentioned. As a coating method on the paper surface, a known method can be adopted. Examples of the coating method include an impregnation method, a bar coater method, a calendar method, a spray method, a method such as a two-roll size press, and a film transfer method such as a gate roll size press and a shim size press. Moreover, the coating amount of the paper coating surface coating agent is usually about 0.01 to ² g / m ² (solid content), preferably 0.04 to 1 g / m ² .

EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated concretely, this invention is not limited to each of these examples. In each example, all parts and% are based on weight unless otherwise specified.

Synthesis example 1
In a flask equipped with a stirrer, condenser, dropping funnel, nitrogen inlet tube and thermometer, 70 parts of styrene, 30 parts of dimethylaminoethyl methacrylate, 42.9 parts of isopropyl alcohol, and 2,2'-azobisisobutyro 2.5 parts of nitrile was charged, and a polymerization reaction was performed at 80 to 85 ° C. for 5 hours while stirring under a nitrogen stream. Subsequently, 11.5 parts of acetic acid and 300 parts of water were added. Thereafter, 17.7 parts of epichlorohydrin was added to the obtained copolymer, and the mixture was kept at 80 ° C. for 2 hours to quaternize the copolymer to form a cationic copolymer compound, and then a predetermined amount of water was added. The solid content concentration was adjusted to 20% to obtain a cationic water-soluble polymer (B1). Table 1 shows the viscosity and pH of the obtained cationic water-soluble polymer (B1). The viscosity was measured by placing a sample in a 225 ml mayonnaise bottle and using a BM viscometer (manufactured by TOKIMEC) at 25 ° C. (the same applies to the following examples).

Synthesis Examples 2-8
In Synthesis Example 1, the same manner as in Synthesis Example 1 except that the type and amount of monomers used in the synthesis and the amount of quaternizing agent by epichlorohydrin used in quaternization were changed as shown in Table 1. Thus, various cationic water-soluble polymers (B2 to B8) having a solid content concentration of 20% were obtained. Table 1 shows the viscosity and pH of the obtained cationic water-soluble polymer (B2 to B8) at 25 ° C.

The symbols in the table are as follows. St: Styrene, BA: Butyl acrylate, MMA: Methyl methacrylate, DMA: N, N-dimethylaminoethyl methacrylate, DMAA: N, N-dimethylaminopropylacrylamide, ECH: Epichlorohydrin Also, component (b1) to component (b3) The amount used represents parts by weight, and the amount used of the quaternizing agent represents the molar ratio relative to component (b2) or component (b3).

Preparation Example 1
Into a flask, 80 parts of an alkyl ketene dimer derived from a 65/35 parts mixed fatty acid of stearic acid and palmitic acid and a 10% cationized starch paste liquid (nitrogen content 0.5 ~ 0.6%, 185 parts of oxidized starch cation-modified with glycidyltrimethylammonium chloride) 5.55 parts of 40% aqueous solution of anionic dispersant (naphthalene sulfonic acid formalin condensate; manufactured by Kao Corporation), In addition, 131.3 parts of deionized water was charged, heated to 70 to 80 ° C., preliminarily dispersed with a homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), and then at a temperature of 300 kg / cm ² . The mixture was forcedly dispersed by passing twice through a high-pressure homogenizer (APV, manufactured by GAULIN). Then, it cooled to 25 degreeC and obtained the ketene dimer emulsion of 20% of solid content concentration, pH 3.4, the viscosity of 10 mPa * s, and the particle diameter of 0.7 micrometer.

Preparation Example 2
A ketene dimer emulsion having a solid content of 20%, a pH of 3.5, a viscosity of 13 mPa · s, and a particle size of 0.6 μm, except that the alkyl ketene dimer of Preparation Example 1 was changed to an alkenyl ketene dimer derived from oleic acid. Got.

Production Example 1
In a flask equipped with a stirrer, a condenser tube, a dropping funnel, a nitrogen introduction tube and a thermometer, 125 parts of the cationic water-soluble polymer (B1) obtained in Synthesis Example 1, 50 parts of styrene as the hydrophobic monomer (A), 50 parts of isobutyl acrylate, 11.1 parts (3 parts as solid content) as a cationic surfactant (trade name: Cotamine 24P, manufactured by Kao Corporation) and 340 parts of water are added, and 2,2′-azobis-2 -2.5 parts of amidinopropane-hydrochloride was added and a polymerization reaction was carried out at a reaction temperature of 70 ° C for 5 hours. Thereafter, a predetermined amount of water was added to adjust the solid content to 20% to obtain a component (C).

Production Examples 2 to 17
In Production Example 1, component (C) was prepared in the same manner as in Production Example 1 except that the types and amounts of component (a1), component (a2) and component (B) were changed as shown in Table 2.

The symbols in the table are as follows.
St: Styrene, BA: Butyl acrylate, IBA: Isobutyl acrylate, 2EHA: 2-ethylhexyl acrylate, AN: Acrylonitrile, HEMA: Hydroxyethyl methacrylate, Cotamin 24P: “Coutamin 24P” (27% lauryltrimethylammonium chloride) manufactured by Kao Corporation solution)
* 1: The amount used is a weight ratio (in terms of solid content) to the hydrophobic monomer (a1).

Example 1
100 g of component (C) obtained in Production Example 1, 100 g of 20% aqueous solution of aluminum sulfate, and 50 g of AKD emulsion obtained in Preparation Example 1 are mixed to obtain a surface sizing agent for emulsion-type papermaking having a solid content concentration of 20%. It was. Table 3 shows the viscosity, pH, and average particle size of the obtained paper surface sizing agent at 25 ° C.

Examples 2-22
In Example 1, an emulsion type having a solid content concentration of 20% was prepared in the same manner as in Production Example 1 except that the types and amounts of components (C), (D) and (E) were changed as shown in Table 3. A surface sizing agent for papermaking was obtained. Table 3 shows the viscosity, pH, and average particle size of the obtained paper surface sizing agent at 25 ° C.

Comparative Example 1
Various surface sizing agents for papermaking having a solid content concentration of 20% were obtained in the same manner as in the Examples except that aluminum sulfate and the AKD emulsion obtained in Preparation Example 1 were not mixed. Table 3 shows the viscosity, pH, and average particle size of the obtained paper surface sizing agent at 25 ° C.

Comparative Examples 2-3
The AKD emulsion obtained in Preparation Example 1 or 2 was used as it was. Table 3 shows the viscosity, pH, and average particle size of the obtained paper surface sizing agent at 25 ° C.

Comparative Example 4
Various surface sizing agents for papermaking having a solid concentration of 20% were obtained in the same manner as in Example 1 except that the AKD emulsion obtained in Preparation Example 1 was not mixed. Table 3 shows the viscosity, pH, and average particle size of the obtained paper surface sizing agent at 25 ° C.

Comparative Example 5
Various surface sizing agents for papermaking having a solid content concentration of 20% were obtained in the same manner as in Example 1 except that aluminum sulfate was not mixed. However, it was not evaluated because it was thickened when left for one month and its long-term stability was poor.

Comparative Example 6
Various surface sizing agents for papermaking having a solid content concentration of 20% were obtained in the same manner as in Example except that the cationic water-soluble polymer (B1) obtained in Synthesis Example 1 was used instead of Component (C). It was. However, it was not evaluated because it was thickened when left for one month and its long-term stability was poor.

The amount of each component in the table is a weight ratio (in terms of solid content) to the total amount of the cationic polymer (C), the water-soluble aluminum compound (D), the alkyl ketene dimer and / or the alkenyl ketene dimer (E). It is.

(Performance test of paper sizing agent)
A coating solution is prepared using each of the papermaking surface sizing agents of Examples 1 to 22 and Comparative Examples 1 to 4, and applied to neutral high-quality base paper, acidic high-quality base paper and paperboard according to the following method. The performance of was evaluated. The results are shown in Tables 4-5.

(Preparation of coating solution)
The coating solution was gelatinized with an oxidized starch (Oji Ace A made by Oji Corn Starch Co., Ltd.) with a solid concentration of 15%, and this was used to prepare an oxidized starch with a solid content concentration of 7%, Examples and Comparative Examples. A coating solution containing 0.5% of the paper surface sizing agent was prepared and subjected to a performance test.

(Stick human sizing degree)
In accordance with JIS P-8122, the Steecht sizing degree (second) was measured. The larger the value, the better the sizing degree.

(Inkjet aptitude evaluation (feathering test))
For the evaluation of feathering, a straight line with a constant line width that is orthogonal in monochrome is printed on the coated paper subjected to the above size processing using an inkjet printer PIXUS iP4200 manufactured by Canon Inc., and blurring of the outer edge of the straight line is visually observed. This was done by visual evaluation. The case where there was no feathering was set to 6, and the case where the ink oozed out and the line became thick overall was set to 1.

(Inkjet aptitude evaluation (print density test))
Ink jet aptitude evaluation was performed by monochrome printing on each of the sized printing paper using a Canon Inkjet printer PIXUS iP4200. Next, the density of the printed part obtained using a reflection densitometer (trade name “Gretag D186”, manufactured by Gretag Macbeth Co., Ltd.) was measured. The larger the value, the higher the print density.

(Water absorption test [Cobb method])
Cobb value (g / m ² ) was measured according to JIS P-8140. The contact time with water is 2 minutes, and the smaller the value, the better the sizing degree.

(Slip angle [tilt method])
The static friction coefficient was measured according to the tilt method of JIS P-8147. The smaller the sliding angle, the easier it is to slip.

(Average particle size)
The particle size was measured with a laser diffraction / scattering method LASER DIFFRACTION PARTICLE SIZE ANALYZER SALD-2000J (manufactured by Shimadzu Corporation).

(PH)
Using a glass electrode pH meter (manufactured by Horiba, Ltd.), the temperature of the coating solution was adjusted to 40 ° C. and measured.

(Evaluation with neutral fine paper)
A neutral paper having a basis weight of 70 g / m ² was made at pH 7.2 using a slurry having the following composition.
Blending of slurry: 65 parts of L-BKP (360 ml CSF), 35 parts of N-BKP (420 ml CSF), 10 parts of calcium carbonate (Tama Pearl 121 manufactured by Okutama Kogyo Co., Ltd.), neutral rosin sizing agent (Size Pine NT-78 Arakawa Chemical) Kogyo Co., Ltd.) 0.2 part, aluminum sulfate 1 part, cationized starch (Cata 3210 made by Nippon NSC) 1 part, yield improver (Polytension 1000 Arakawa Chemical Industries, Ltd.) 0.03 part.
A coating solution prepared using the surface sizing agent for papermaking of Examples and Comparative Examples was applied to the obtained base paper on both sides using a bar coater, and then passed through a rotary drum dryer at 105 ° C. for 1 minute. The coated papers were obtained by drying, and their sizing human sizing degree and ink jet suitability (feathering characteristics) were measured. The results are shown in Table 4. The starch adhesion amount and the surface sizing agent solid adhesion amount are values calculated from the weight of the coating liquid before and after coating.

(Evaluation with paperboard)
A paperboard base paper having a basis weight of 180 g / m ² was used as the base paper.
After coating the base paper with the coating solution prepared using the paper sizing agent of Examples and Comparative Examples using a bar coater, the coating liquid was dried by passing it through a rotary drum dryer at 105 ° C. for 1 minute. Papers were obtained and their water absorption (Cobb method) was measured. The results are shown in Table 5.

Claims (8)

Polymer (C) obtained by polymerizing vinyl monomer (A) containing hydrophobic monomer (a1) in the presence of cationic water-soluble polymer (B), water-soluble aluminum compound (D), and alkyl An aqueous emulsion type paper sizing agent containing a ketene dimer and / or an alkenyl ketene dimer (E). Polymerization of alkyl ketene dimer and / or alkenyl ketene dimer (E) from 5 to 40% by weight and vinyl monomer (A) containing hydrophobic monomer (a1) in the presence of cationic water-soluble polymer (B) The surface sizing agent for papermaking according to claim 1, wherein the total amount of the polymer (C) and the water-soluble aluminum compound (D) obtained in this manner is 95 to 60% by weight (in terms of solid content). Content ratio of polymer (C) obtained by polymerizing vinyl monomer (A) containing hydrophobic monomer (a1) in the presence of cationic water-soluble polymer (B) and water-soluble aluminum compound (D) The surface sizing agent for papermaking according to claim 1 or 2, wherein (solid content weight ratio) is (C) / (D) = 20/80 to 80/20. The cationic water-soluble polymer (B) is obtained by converting the hydrophobic monomer (b1) and the (meth) acrylic acid dialkylaminoalkyl ester (b2) and / or the (meth) acrylic acid dialkylaminoalkylamide (b3) to (b1): [ (B2) + (b3)] = 20 to 90:80 to 10% by weight, and a part or all of amino groups derived from the above (b2) and (b3) are quaternized The surface sizing agent for papermaking according to any one of claims 1 to 3. The content ratio of the vinyl monomer (A) containing the hydrophobic monomer (a1) to the cationic water-soluble polymer (B) is (A) :( B) = 1: 4 to 4: 1 by weight. Item 5. A paper-making surface sizing agent according to any one of Items 1 to 4. The water-soluble aluminum compound (D) is at least one selected from the group consisting of aluminum sulfate, aluminum chloride, aluminum nitrate, basic aluminum sulfate, basic aluminum chloride, aluminum sulfate oxalate and polymers thereof. Item 6. A paper size sizing agent according to any one of Items 1 to 5. The surface sizing agent for papermaking and starches (F) according to any one of claims 1 to 6, wherein the surface sizing agent for papermaking: starches (F) has a weight of 0.1 to 20: 99.9 to 80. Surface size coating solution formulated to have a ratio (in terms of solid content). Paper obtained by applying the surface sizing agent for papermaking according to any one of claims 1 to 6 or the surface size coating liquid according to claim 7.