JP2010196217A - Coated paper for gravure printing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide coated paper for gravure printing, having a low density and high white paper glossiness, and with a good gravure printing aptitude. <P>SOLUTION: This coated paper for gravure printing, is obtained by installing a coated layer containing a pigment and an adhesive on stock paper installed with a surface-treating agent, wherein the surface-treating agent includes a cationic group-containing copolymer obtained by polymerizing at least one kind of (A) components selected from a vinyl monomer expressed by general formula (I) and a vinyl monomer expressed by general formula (II), with at least one kind of (B) components selected from a cationic group-containing vinyl monomer expressed by general formula (III) and a cationic group-containing vinyl monomer expressed by general formula (IV) in a (97/3) to (30/70) molar ratio of the component (A) to the component (B). <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a coated paper for gravure printing having an excellent white paper appearance and good gravure printability.

  Gravure printing is intaglio printing in which ink in a concave portion of a plate is transferred under pressure, and is excellent in gradation reproducibility, and is therefore used in commercial printing fields such as magazines, catalogs, and brochures. In recent years, there has been a strong demand for weight reduction of printed matter from the viewpoint of resource saving, transportation and mailing cost, and a low density and excellent printability has been demanded.

  In gravure printing, the plate is a hard metal roll as compared to offset printing, and the plate is difficult to adhere completely to the paper during printing, so missing dots are generated in which halftone dots are missing during gravure printing. Therefore, the base paper and the coating layer of the coated paper for gravure printing are required to have smoothness and cushioning properties. In order to improve the smoothness of the coating layer surface of the coated paper for gravure printing, it is generally effective to add pigments with high aspect ratio (delaminated clay, talc, etc.) to the coating layer composition It is said that.

  However, blending many pigments with a high aspect ratio in the coating layer composition increases the viscosity of the coating solution, making it difficult to handle during preparation and causing coating defects such as streak and scratch. Cheap. For this reason, it is the present condition that solid content concentration of a paint cannot be made very high, As a result, it becomes necessary to make drying conditions strong, and it leads to high cost. In addition, pigments such as delaminated clay and talc with high aspect ratios were used in large amounts, as can be seen from the fact that they are generally used in low-gloss applications such as matte coated paper. In some cases, the glossiness of the white paper is low, so that it is not suitable for applications that require high white paper glossiness.

  On the other hand, a method is known in which an organic pigment such as a plastic pigment is used to impart high white paper gloss, speckle prevention effect, opacity, and the like (see Patent Document 1). However, since organic pigments are expensive compared to inorganic pigments, the cost is high, and the coating liquid added with organic pigments tends to increase in viscosity under high shearing force, resulting in poor coating such as streak and scratch. Prone to cause. For this reason, it is the present condition that solid content concentration of a paint cannot be made very high, As a result, it becomes necessary to strengthen drying conditions, and there is a problem that it leads to high cost.

In addition, as a technique for mechanically smoothing the surface of the coating layer of the coated paper for gravure printing and imparting white paper glossiness, a high pressure treatment using a super calendar is usually performed. Surface treatment with a supercalender can improve the smoothness and white paper gloss, but at the same time the density of the coated paper is increased and the opacity and stiffness of the coated paper are lost. When the opacity is insufficient, the printed pattern is transmitted and affects the printed pattern on the back surface, or the feeling of blank paper on the back surface is impaired, resulting in a decrease in quality. Also, in order not to lose opacity and stiffness, it is necessary to reduce the pressure treatment to reduce the density, but usually it will simultaneously reduce the glossiness of white paper and increase speckles during gravure printing. The current situation is that the pressure on the super calendar cannot be reduced. Further, even when a soft nip calender is used, there is a problem in that pressurization cannot be sufficiently reduced, the density becomes high, opacity and rigidity decrease, and roll contamination occurs.
As a conventional method, in order to provide a coated paper for gravure printing having a low density, a high white paper glossiness, and improved speckles, a pigment has a volume range of 0.4 to 4.2 μm. There is disclosed a coated paper for gravure printing in which a coating layer containing 50% by weight or more of kaolin having a particle size distribution of 65% or more per 100 parts by weight of pigment and containing calcined kaolin is provided (Patent Document 2). reference). However, although it has a low density, the glossiness of white paper is high and it is insufficient to have gravure suitability.

  As described above, in the prior art, it has been difficult to obtain a coated paper for gravure printing that has low density, high white paper glossiness, and excellent gravure printing suitability.

JP-A 64-020396 JP 2003-221797 A

  In view of the circumstances as described above, an object of the present invention is to provide a coated paper for gravure printing having a low density, a high white paper glossiness, and good gravure printability.

In order to solve the above-mentioned problem, the coated paper for gravure printing according to claim 1 of the present invention is a gravure obtained by providing a coating layer containing a pigment and an adhesive on a base paper provided with a surface treatment agent. A coated paper for printing, comprising at least one component (A) selected from a vinyl monomer represented by the following general formula (I) and a vinyl monomer represented by the general formula (II): At least one component (B) selected from a cationic group-containing vinyl monomer represented by the following general formula (III) and a cationic group-containing vinyl monomer represented by the general formula (IV): Is characterized by containing a cationic group-containing copolymer obtained by polymerizing the component (A) / component (B) at a molar ratio of 97/3 to 30/70.
[Wherein, R ¹ represents a hydrogen atom or a methyl group, and R ² and R ³ are the same or different and represent a hydrogen atom or a linear or branched alkyl group or alkenyl group having 1 to 4 carbon atoms. ]
[Wherein R ¹ represents the above-mentioned meaning, A ¹ and A ² are the same or different, and represent a group represented by the formula — (CH ₂ ) _n — (n represents an integer of 2 to 6). , B represents an —O— or —CH ₂ — group. ]
[R ¹ is as defined above, R ⁴ and R ⁵ are the same or different and each represents an alkyl group or alkenyl group having 1 to 4 carbon atoms, and R ⁶ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Y represents —O—, —NH— or —O—CH ₂ CH (OH) —, Z represents a linear or branched alkylene group having 1 to 4 carbon atoms, and X represents an acid. A conjugated base, a halogen atom or an alkyl sulfate group having 1 to 4 carbon atoms is shown. ]
[Wherein, R ⁷ and R ⁸ are the same or different and each represents a hydrogen atom or a methyl group; R ⁹ and R ¹⁰ are the same or different and each represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; Indicates meaning. ]
Similarly, in the coated paper for gravure printing of the invention according to claim 2 of the present invention, the cationic group-containing copolymer comprises (A) component, (B) component, and further a crosslinkable vinyl monomer. It is obtained by polymerizing the component (C) (excluding the monomer represented by the general formula (IV)).
In the coated paper for gravure printing according to claim 3 of the present invention, the component (A) is selected from (meth) acrylamide, N, N-dimethyl (meth) acrylamide and N, N-diethyl (meth) acrylamide. It is characterized by being at least one or more selected.
In the coated paper for gravure printing of the invention according to claim 4 of the present invention, the amount of the component (C) in the cationic group-containing copolymer is that of the component (A), the component (B) and the component (C). It is characterized by being 0.0005-5 mol% in the total.
The coated paper for gravure printing according to claim 5 of the present invention is characterized in that the coated paper has a white paper glossiness of 50% or more.
The coated paper for gravure printing according to claim 6 of the present invention is characterized in that the coating amount of the surface treatment agent is 0.01 g / m ² or more and 3 g / m ² or less per one side of the base paper.
In the coated paper for gravure printing according to the seventh aspect of the present invention, the coating amount of the coating layer containing the pigment and the adhesive is 3 g / m ² or more and 25 g / m ² or less per one side of the base paper. It is characterized by.

  According to the present invention, it is possible to obtain a gravure-coated paper having a low density, a low halftone dot loss rate, good gravure printing suitability, excellent blank paper glossiness and smoothness, and good gravure printing suitability. The provided gravure printing coated paper can be produced by a low linear pressure calendar process.

The present invention provides a coated paper for gravure printing by providing a coating layer mainly composed of a pigment and an adhesive on a base paper provided with a specific surface treating agent.
As the specific surface treatment agent provided on the base paper of the present invention, those having the following cationic group-containing copolymer as the main component can be suitably used.

[Cationic group-containing copolymer]
The cationic group-containing copolymer according to the present invention includes (A): at least one selected from vinyl monomers represented by the above general formulas (I) and (II), and (B): the above general formula. It is obtained by polymerizing at least one selected from the cationic group-containing vinyl monomers represented by (III) and (IV) at a predetermined molar ratio.

[(A) component]
The cationic group-containing copolymer according to the present invention contains at least one selected from vinyl monomers represented by general formulas (I) and (II) as a constituent component.

[Wherein, R ¹ represents a hydrogen atom or a methyl group, and R ² and R ³ are the same or different and represent a hydrogen atom or a linear or branched alkyl group or alkenyl group having 1 to 4 carbon atoms. The total number of carbon atoms of R ² and R ³ is preferably 6 or less, and more preferably 4 or less. ]

[Wherein R ¹ represents the above-mentioned meaning, A ¹ and A ² are the same or different, and represent a group represented by the formula — (CH ₂ ) _n — (n represents an integer of 2 to 6). , B represents an —O— or —CH ₂ — group. ]

  The monomer of the component (A) of the present invention is preferably hydrophilic. Here, hydrophilicity means the inorganic nature of the monomer from which the polymer units are obtained in the organic conceptual diagram-basics and applications-(written by Yoshio Koda, Sankyo Publishing Co., Ltd., issued on May 10, 1984). The ratio [I / O] between I) and organic (O) means 0.60 or more, preferably 1.00 or more, more preferably 1.30 or more.

  Examples of the vinyl monomer represented by the general formula (I) include (meth) acrylamide, N-methyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, Examples include Nn-propyl (meth) acrylamide, N-isopropyl (meth) acrylamide, Nt-butyl (meth) acrylamide, N-isobutyl (meth) acrylamide, and the like represented by the general formula (II). Examples of vinyl monomers include N- (meth) acryloylmorpholine, but the present invention is not limited to such examples, and these vinyl monomers may be used alone or in combination of two or more. It can be used by mixing. “(Meth) acryl” means acryl and / or methacryl (hereinafter the same).

  Among these monomers (A), (meth) acrylamide and N, N-disubstituted acrylamide are preferable, and (meth) acrylamide, N, N-dimethyl (meth) acrylamide, and N, N-diethyl are further preferable. (Meth) acrylamide is preferred from the viewpoint of production of a cationic group-containing copolymer and from the viewpoint of handling as a surface treatment agent.

[(B) component]
The cationic group-containing copolymer according to the present invention comprises at least one selected from cationic group-containing vinyl monomers represented by general formulas (III) and (IV) as a constituent component.
[R ¹ is as defined above, R ⁴ and R ⁵ are the same or different and each represents an alkyl group or alkenyl group having 1 to 4 carbon atoms, and R ⁶ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Y represents —O—, —NH— or —O—CH ₂ CH (OH) —, Z represents a linear or branched alkylene group having 1 to 4 carbon atoms, and X represents an acid. A conjugated base, a halogen atom or an alkyl sulfate group having 1 to 4 carbon atoms is shown. ]

[Wherein, R ⁷ and R ⁸ are the same or different and each represents a hydrogen atom or a methyl group; R ⁹ and R ¹⁰ are the same or different and each represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; Indicates meaning. ]

  Specific examples of the compound represented by the general formula (III) include acid neutralized products obtained by neutralizing (meth) acrylic acid esters or (meth) acrylamides having a dialkylamino group exemplified above with an acid, or 4 A quaternary ammonium salt quaternized with a classifier may be mentioned, and specific examples of the compound represented by the general formula (IV) include the diallyl-type quaternary ammonium salts exemplified above.

  Preferred acids for obtaining the above acid neutralized product include hydrochloric acid, sulfuric acid, nitric acid, acetic acid, formic acid, maleic acid, fumaric acid, citric acid, tartaric acid, adipic acid, sulfamic acid, toluenesulfonic acid, lactic acid, pyrrolidone- Examples of preferred quaternizing agents for obtaining the quaternary ammonium salts include alkyl halides such as methyl chloride, ethyl chloride, methyl bromide and methyl iodide, and dimethyl sulfate. And general alkylating agents such as diethyl sulfate and di-n-propyl sulfate.

  Among the compounds represented by the general formulas (III) and (IV), dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylamide, diethylaminopropyl ( A quaternary ammonium salt obtained by quaternizing (meth) acrylamide with the above quaternizing agent, or dimethyldiallylammonium chloride may be mentioned.

  Specific examples of the cationic group-containing vinyl monomer include dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dipropylaminoethyl (meth) acrylate, diisopropylaminoethyl (meth) acrylate, dibutylaminoethyl. (Meth) acrylate, diisobutylaminoethyl (meth) acrylate, di-t-butylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylamide, diethylaminopropyl (meth) acrylamide, dipropylaminopropyl (meth) acrylamide, diisopropylamino Propyl (meth) acrylamide, dibutylaminopropyl (meth) acrylamide, diisobutylaminopropyl (meth) acrylamide, di-t-butylamino Acid neutralized products or quaternary ammonium salts of monomers having amino groups such as (meth) acrylic acid esters or (meth) acrylamides having dialkylamino groups such as propyl (meth) acrylamide; dimethyldiallylammonium chloride, diethyl Diallyl-type quaternary ammonium salts such as diallylammonium chloride; vinylpyridines such as 4-vinylpyridine and 2-vinylpyridine; N-vinyl heterocyclic compounds such as N-vinylimidazole; aminoethyl vinyl ether, dimethylaminoethyl vinyl ether, etc. And acid neutralized products of quaternary ammonium salts such as vinyl ethers and the like. “(Meth) acrylate” means acrylate and / or methacrylate (the same applies hereinafter).

[Mixing ratio of monomer components]
In the cationic group-containing copolymer according to the present invention, the composition ratio (molar ratio) of the component (A) and the component (B) is (A) component / (B) component, and 97/3 to 30/70. The ratio is preferably 97/3 to 40/60. If it is within these composition ratios, when a coating liquid mainly composed of a pigment and an adhesive is applied, a part of the coating liquid aggregates, and the copolymer is instantaneously contained in the coating liquid. As a result of absorbing the moisture, an effect that the penetration of the coating liquid into the paper can be suppressed is exhibited. Furthermore, when it exists in the said composition ratio, the adhesive force to the paper surface of a surface treating agent improves, and it can fully suppress the peeling strength fall of a base paper and a coating layer.
When the composition ratio of the component (A) and the component (B) exceeds 97/3, the copolymer is not imparted with ionicity, and when coated and dried, it shrinks due to drying and the coverage of the base paper descend. Moreover, when it is less than 30/70, it is difficult for the copolymer to have a high molecular weight, and the water in the coating solution cannot be sufficiently held.

  The cationic group-containing copolymer according to the present invention preferably has a total of (A) component and (B) component of 80 to 100 mol%, more preferably 90 to 99.9 in the constituent monomers. Mol%.

[(C) component]
The cationic group-containing copolymer according to the present invention may be a crosslinkable vinyl monomer (excluding the monomer represented by the general formula (IV)) as the component (C) as necessary. It can be a component. The crosslinkable vinyl monomer preferably has at least two groups selected from a vinyl group, an acryloyl group, a methacryloyl group and an allyl group in the molecule. Examples of the crosslinkable vinyl monomer having at least two vinyl groups in the molecule include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, and propylene glycol di (meth) acrylate. , Dipropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, 1,2-butylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate Of polyhydric alcohols such as glycerin di (meth) acrylate, glycerin tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, etc. ) Acrylic esters; Acrylamides such as N-methylallylacrylamide, N-vinylacrylamide, N, N′-methylenebis (meth) acrylamide, and bisacrylamideacetic acid; Divinyl compounds such as divinylbenzene, divinyl ether, and divinylethyleneurea; Polyallyl compounds such as diallyl phthalate, diallyl malate, diallylamine, triallylamine, triallyl ammonium salt, allyl etherified product of pentaerythritol, and allyl etherified product of sucrose having at least two allyl ether units in the molecule; vinyl ( (Meth) acrylate, allyl (meth) acrylate, (meth) acrylic acid esters of unsaturated alcohols such as 2-hydroxy-3-acryloyloxypropyl (meth) acrylate, etc. It is below.

  Among these crosslinkable vinyl monomers, ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, divinylbenzene, pentaerythritol triallyl ether, and pentaerythritol tetraallyl ether are preferable.

  In the cationic group-containing copolymer according to the present invention, the ratio of the crosslinkable vinyl monomer of the component (C) is 0 in the total of the component (A), the component (B), and the component (C). 0.005 to 5 mol% is preferable, and 0.001 to 1 mol% is particularly preferable. That is, (C) component / [(A) component + (B) component + (C) component] × 100 (mol%) is preferably 0.0005 to 5 mol%, more preferably 0.001 to 1 mol%. . When the ratio of the crosslinkable vinyl monomer is 0.0005 mol% or more, the degree of crosslinking of the obtained cationic group-containing copolymer is appropriate, and the cationic group-containing copolymer was applied to paper. At this time, the ratio of staying on the paper surface is improved, and it is difficult to penetrate into the paper. For this reason, when the coating liquid is applied, a part of the coating liquid aggregates or the cationic group-containing copolymer is present on the paper surface. When the liquid is applied, by instantly absorbing moisture in the coating liquid, the coating liquid becomes highly viscous and non-fluidized, or when the cationic group-containing copolymer is applied to the paper surface, By filling the pores of the paper having the porous surface layer portion, the effect of suppressing the penetration of the coating liquid into the base paper is sufficiently exhibited. When the amount is 5 mol% or less, when the cationic group-containing copolymer is applied to paper, the water in the coating liquid is absorbed even when the cationic group-containing copolymer is applied to the coating liquid. In view of the result that the coating liquid becomes highly viscous and the non-fluidizing effect can be maintained without lowering the ability of the coating liquid, it is preferable that the coating liquid hardly penetrates into the paper. In addition, when (C) component is used, the total of (A) component, (B) component, and (C) component is 90-100 mol in the structural monomer in the cationic group containing copolymer which concerns on this invention. %, More preferably 95 to 100 mol%.

[Other monomer components]
The cationic group-containing copolymer according to the present invention is a copolymer having the at least two kinds of vinyl monomers as essential constituents, and preferably further having the crosslinkable vinyl monomer as a constituent. Other vinyl monomers copolymerizable with these vinyl monomers can also be used as constituents.

  Examples of other vinyl monomers include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, neopentyl (meth) acrylate, cyclopentyl (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, n-octyl (meth) acrylate, Isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, Ryl (meth) acrylate, isostearyl (meth) acrylate, behenyl (meth) acrylate, phenyl (meth) acrylate, toluyl (meth) acrylate, xylyl (meth) acrylate, benzyl (meth) acrylate, 2-ethoxyethyl (meth) Acrylate, 2-butoxyethyl (meth) acrylate, 2-phenoxy (meth) acrylate, 2-methoxypropyl (meth) acrylate, 3-methoxypropyl (meth) acrylate, 2-ethoxypropyl (meth) acrylate, 3-ethoxypropyl (Meth) acrylate, ethylene glycol mono (meth) acrylate, diethylene glycol mono (meth) acrylate, triethylene glycol mono (meth) acrylate, tetraethylene glycol mono ( ) Acrylate, polyethylene glycol # 210 mono (meth) acrylate, polyethylene glycol # 400 mono (meth) acrylate, polyethylene glycol # 600 mono (meth) acrylate, polyethylene glycol # 1000 mono (meth) acrylate, methoxyethylene glycol (meth) Acrylate, methoxydiethylene glycol (meth) acrylate, methoxytriethylene glycol (meth) acrylate, methoxytetraethylene glycol (meth) acrylate, methoxypolyethylene glycol # 210 (meth) acrylate, methoxypolyethylene glycol # 400 (meth) acrylate, methoxypolyethylene glycol # 600 (meth) acrylate, methoxypolyethylene glycol # 100 (Meth) acrylic acid derivatives such as 0 (meth) acrylate (numbers after # indicate weight average molecular weight); 2-acrylamido-2-methylpropanesulfonic acid, sodium styrenesulfonate, acrylic acid, methacrylic acid, Anionic group-containing monomers such as 2-sulfoethyl methacrylate; N- (3-sulfopropyl) -N-acryloyloxyethyl-N, N-dimethylammonium betaine, N- (3-sulfopropyl) -N-methacryloyl Amidopropyl-N, N-dimethylammonium betaine, N- (3-carboxymethyl) -N-methacryloylamidopropyl-N, N-dimethylammonium betaine, N- (3-sulfopropyl) -N-methacryloyloxyethyl-N , N-dimethylammonium betaine, N-carbo Shimechiru -N- methacryloyloxyethyl -N, betaines such as N- dimethylammonium betaine.

[Polymerization method]
The method for producing the cationic group-containing copolymer according to the present invention is not necessarily limited, but it is usually preferable to use a method such as an aqueous solution polymerization method, a reverse phase suspension polymerization method or a precipitation polymerization method. For example, as an aqueous solution polymerization method, a monomer component and a crosslinking agent are uniformly dissolved in water or a hydrophilic organic solvent that can be uniformly mixed with water, or a solvent such as a mixed solvent thereof. A method may be mentioned in which dissolved oxygen in the system is removed by substitution with an inert gas or the like, and then a polymerization initiator is added and reacted. The polymerization initiation temperature is usually about 20 to 90 ° C., and the reaction time is about 1 to 10 hours. When using a component that is hardly soluble in water as a monomer, it is desirable to use a hydrophilic organic solvent in combination.

  Representative examples of the hydrophilic organic solvent include, for example, lower alcohols such as methyl alcohol, ethyl alcohol, and propyl alcohol, cyclic ethers such as tetrahydrofuran and dioxane, acetone, acetonitrile, dimethylformamide, dimethylacetamide, dimethylsulfoxide, and the like. Can be mentioned. Of these, tetrahydrofuran, acetonitrile, dimethylformamide, dimethylacetamide, dimethylsulfoxide and the like are particularly preferable.

  In addition, as the polymerization initiator, a peroxide that is uniformly dissolved in a solvent, an organic or inorganic peracid or a salt thereof, an azobis-based compound alone or a redox-based compound in combination with a reducing agent is used. Typical examples include, for example, t-butyl peroxide, t-amyl peroxide, cumyl peroxide, acetyl peroxide, propionyl peroxide, benzoyl peroxide, benzoyl isobutyryl peroxide, lauroyl peroxide, t-butyl. Hydroperoxide, cyclohexyl hydroperoxide, tetralin hydroperoxide, t-butyl peracetate, t-butyl perbenzoate, bis (2-ethylhexyl peroxydicarbonate), 2,2′-azobisisobutyronitrile, Phenylazotriphenylmethane, 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2′-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride, sodium persulfate, potassium persulfate, ammonium persulfate, hydrogen peroxide, persulfate and triethylamine, triethanolamine, dimethyl Examples include combinations with tertiary amines such as aniline.

  Of these, t-butyl peroxide, benzoyl peroxide, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2′-azobis [ 2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2′-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride, sodium persulfate, Preference is given to potassium sulfate or ammonium persulfate alone, or a combination of these persulfates with tertiary amines such as triethylamine, triethanolamine or dimethylaniline.

  There is no restriction | limiting in particular as a polymerization apparatus used when manufacturing the copolymer of this invention, For example, a general kneader and a cylindrical reaction container are used.

  In the aqueous solution polymerization method, an example of the procedure for producing the copolymer of the present invention is shown. An aqueous solution of 10 to 50% by weight of the monomer mixture is fed into a kneader having a lid, and the system is changed as necessary. Substitution with an inert gas such as nitrogen, addition of a water-soluble radical polymerization initiator, the polymerization is started at 20 to 90 ° C., and the water-containing gel-like polymer produced with the progress of the polymerization is rotated by the kneader blades. There can be mentioned a method of completing the polymerization while being subdivided by the shearing force of. Of course, the scope of the present invention is not limited by this example. The initial concentration of the aqueous monomer mixture used here is preferably 10 to 50% by weight.

  The amount of the polymerization initiator used is in the range of 0.01 to 5 mol%, preferably 0.01 to 3 mol%, particularly preferably 0.01 to 1 mol%, based on the monomer component. Incidentally, when the amount of the polymerization initiator used is 5 mol% or less based on the monomer component, the degree of polymerization of the polymer chain of the main chain is increased, and the proportion of polymer chains that are not crosslinked is reduced. Performances such as expected water absorption capacity and thickening action are fully exhibited. On the other hand, the content of 0.01 mol% or more is preferable because the reaction rate of the polymerization reaction is increased and the amount of residual monomer is reduced.

  The reaction product is in the form of a gel containing the solvent used in the reaction, and is usually pulverized with a rotary cutter or the like, further dried by removing the solvent by a method such as heating or decompression, and pulverized to obtain a powder.

  Further, an aqueous solution polymerization method using a general cylindrical closed reaction vessel is also used. In this case, the system is replaced with an inert gas such as nitrogen as necessary while adding or dripping an aqueous solution of 10 to 50% by weight of the monomer mixture, and a water-soluble radical polymerization initiator is added. In addition, there is a method in which polymerization is started by heating at room temperature or 30 to 80 ° C. to obtain a liquid copolymer.

  In the reversed-phase suspension polymerization method, the monomer component and the crosslinking agent are uniformly dissolved in water and the polymerization reaction is performed by suspending or emulsifying in an organic solvent that is not uniformly mixed with water using a dispersant or the like. . As a polymerization initiator, not only a water-soluble thing but a thing soluble in an organic solvent is necessarily used. As the organic solvent used here, in addition to the above, for example, hydrocarbon organic solvents such as hexane, cyclohexane, heptane, octane, benzene, toluene, xylene, ethylbenzene, and halogenated carbonization such as carbon tetrachloride and dichloroethane. Hydrogen-based organic solvents, mineral oil such as Isobar, etc. are also used.

  Further, as the dispersant, for example, sorbitan monostearate, sorbitan monopalmitate, polyvinyl alcohol, methyl cellulose, ethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, carboxyethyl cellulose, sugar ester, etc., and more generally used as an emulsifying dispersant. Surfactant etc. are mentioned.

  Removal of dissolved oxygen in the system, treatment of reaction products, etc. are the same as described above, and the reaction conditions are not necessarily limited, but are generally as follows. Solvent usage: equimolar to 20 times, preferably equivalent to 10 times the amount of the monomer aqueous solution, polymerization initiator usage: 0.01 to 5 mol%, preferably 0.01 to 3 mol% based on the monomer component Polymerization start temperature: about 10 to 90 ° C., reaction time: about 1 to 10 hours.

In the present invention, by providing a surface treatment agent containing the above cationic group-containing copolymer on the base paper, it has a low density and a low dot loss rate, and has good gravure printing suitability, blank paper glossiness, The reason why a coated paper for gravure printing excellent in smoothness can be obtained is considered as follows.
By providing a surface treatment agent containing the cationic group-containing copolymer according to the present invention on a base paper and providing a coating layer mainly composed of a pigment and an adhesive, the base paper can be obtained due to the high water absorption effect of the surface treatment agent. Since the penetration of the coating solution into the ink is suppressed and the base paper coverage of the coating layer is improved, it is considered that the printability, white paper glossiness and smoothness are excellent.
This cationic group-containing copolymer is preferably a main component as a surface treatment agent in order to have an effect of improving the glossiness of white paper and improving the smoothness, and is 50% by weight or more per weight of the solid content of the surface treatment agent. Preferably, it is 80 to 100% by weight. As a surface treatment agent, in addition to the cationic group-containing copolymer, a natural or synthetic resin adhesive for general paper coating such as starch and polyvinyl alcohol, fluidity, etc., in addition to the cationic group-containing copolymer. A regulator, antifoaming agent, mold release agent, colorant and the like may be appropriately combined and mixed to form a surface treatment agent.

As the surface treatment agent of the present invention, it is preferable to apply 0.01 g / m ² or more and 3 g / m ² or less per side of the surface treatment agent as a cationic group-containing copolymer on a base paper, more preferably 0. .5g / ^{m 2} or more, more preferably to use 1.0 g / ^{m 2} or more, thereby obtaining a coating base paper. By applying an application amount of the base paper surface treatment agent of 0.01 g / m ² or more on one side, the coated paper surface becomes smooth, cushioning properties are imparted, and blank paper glossiness and gravure printing suitability are improved. When the coating amount of the base paper surface treatment agent is 0.01 g / m ² or less on one side, the base paper surface treatment agent cannot sufficiently cover the base paper surface, and therefore the effect of improving the white paper glossiness and gravure printability is extremely small. Further, even if it exceeds 3 g / m ² , no further increase in effect can be expected.

  In the present invention, chemical pulp, semi-chemical pulp, mechanical pulp, waste paper pulp, and the like can be used as the pulp constituting the base paper, but it is preferable to contain 10% by weight or more of mechanical pulp. Mechanical pulp has a stiffer fiber than chemical pulp, so the base paper blended with mechanical pulp is less crushed by various pressures applied in the paper making process, and becomes bulky as a whole, increasing the amount of voids inside the base paper, Opacity is improved and stiffness is increased at the same time. Among mechanical pulps, ground pulp can be preferably used because it contributes greatly to reducing the density. When the blending amount of the mechanical pulp is less than 10% by weight, the opacity and rigidity are relatively inferior even if the filler and calendar conditions are optimized. The mechanical pulp is preferably 60% by weight or less of the pulp for papermaking from the viewpoint of whiteness and suitability for coating. In particular, the use of waste paper pulp is preferable in terms of effective use of resources and environmental friendliness.

  In the base paper of the present invention, by using a bulking agent (a low density agent) such as a surfactant which is an organic compound having an action of inhibiting the interfiber bonding of pulp, the gravure printing suitability can be reduced at a lower density. Can be improved. An organic compound having an action of inhibiting the interfiber bonding of pulp (hereinafter abbreviated as a binding inhibitor) is a compound having a hydrophobic group and a hydrophilic group, and has recently been put on the market for paper making to increase the bulk of paper. Further, the density-reducing agent (or bulking agent) is suitable as a binding inhibitor of the present invention. For example, W098 / 03730, JP-A-11-200284, JP-A-11-350380, JP-A-2003-2003 No. 96694, Japanese Patent Application Laid-Open No. 2003-96695, and the like. Specifically, higher alcohol ethylene and / or propylene oxide adduct, polyhydric alcohol type nonionic surfactant, higher fatty acid ethylene oxide adduct, polyhydric alcohol and fatty acid ester compound, polyhydric alcohol and fatty acid Ethylene oxide adducts of these ester compounds, fatty acid polyamidoamines, fatty acid diamidoamines, fatty acid monoamides, or polyalkylenepolyamine / fatty acid / epichlorohydrin condensates can be used alone or in combination of two or more. can do. Preferred are polyhydric alcohol and fatty acid ester compounds, fatty acid diamide amines, fatty acid monoamides, polyalkylene polyamines / fatty acids / epichlorohydrin condensates and the like. These bulking agents may be used alone or in combination of two or more. In order to improve the air permeability of the base paper, the coated paper of the present invention preferably contains 0.1 to 10 parts by weight of pulp interfiber binding inhibitor per 100 parts by weight of pulp, in particular 0.2 to 1. It is preferable to contain 0.0 part by weight. In addition, chemicals usually used in the paper making process, for example, paper strength enhancers, sizing agents, antifoaming agents, colorants, softening agents, and the like are added to these paper stocks as necessary.

There are no particular restrictions on the paper making method of the base paper, and long paper machines including top wires, round net machines, machines using the two together, Yankee dryer machines, etc., acid paper making, neutral paper making, alkaline Any of the base papers produced by the paper making method can be used, and medium base papers containing recovered waste paper pulp obtained from used newspapers can also be used. By applying a specific surface treatment agent to these base papers, Obtainable. As a method of providing the surface treatment layer on the base paper, one or both sides are coated on the base paper using a blade coater, bar coater, air knife coater, reverse roll coater, curtain coater, metering size press coater, gate roll coater or the like. Range of coating amount present invention to be effective, preferably per side 0.1 g / ^{m 2} or more 3 g / ^{m 2} or less, more preferably 0.3 g / ^{m 2} or more 3 g / ^{m 2} or less, more preferably Is 1 g / m ² or more and 3 g / m ² or less.
The coating base paper, basis weight of 30 to 400 g / ^{m 2} to be used for general coated paper, preferably of the order of 30 to 200 g / ^{m 2} is used as appropriate. In the present invention, the density of the coated base paper is preferably 0.3 g / cm ³ or more and 0.7 g / cm ³ or less, more preferably 0.3 g / cm ³ or more and 0.6 g / cm ³ or less. is there. By using a coating base paper having a density of 0.3 g / cm ³ or more and 0.7 g / cm ³ or less, a coating liquid containing a pigment and an adhesive specified in the present invention is applied to thereby reduce the coating amount. Even if it is reduced, the coverage of the base paper is good, so that the ink deposition property is excellent and the density can be further reduced. When the density of the coating base paper is less than 0.3 g / cm ³ , the permeability of the coating liquid increases and the coating suitability tends to be inferior.
In the present invention, a coated paper in which a coating layer is provided can be obtained by coating and drying a coating liquid containing a pigment and an adhesive on a coated base paper in which a surface treatment agent is provided on the base paper.

  As a pigment used for the coating layer of this invention, a several pigment can be used together in the range which does not impair the objective of invention. As inorganic pigments, conventionally used for coated paper, kaolin, clay, engineered kaolin, delaminated clay, heavy calcium carbonate, light calcium carbonate, talc, titanium dioxide, calcium sulfate, barium sulfate, These are inorganic pigments such as zinc oxide, silicic acid, silicate, colloidal silica, and satin white. These inorganic pigments can be used alone or in combination of two or more. In addition to inorganic pigments, organic pigments can also be used.

  As an adhesive used for the coating layer of the present invention, a plurality of adhesives can be used in combination as long as the object of the invention is not impaired. Various adhesives such as styrene / butadiene, styrene / acrylic, ethylene / vinyl acetate, butadiene / methyl methacrylate, and vinyl acetate / butyl acrylate, which have been used for coated papers. Or synthetic adhesives such as maleic anhydride copolymer, acrylic acid / methyl methacrylate copolymer; proteins such as casein, soy protein, synthetic protein; oxidized starch, positive starch, urea phosphated starch, hydroxyethyl One or more ordinary adhesives for coated paper such as etherified starch such as etherified starch are appropriately selected and used. Moreover, in order to improve bulkiness and cushioning properties, the starch content is preferably 5 parts by weight or less, more preferably 3 parts by weight or less with respect to 100 parts by weight of the pigment. The total amount of these adhesives is 3 to 30 parts by weight, more preferably 3 to 12 parts by weight per 100 parts by weight of the pigment. The adhesive used in the present invention is preferably a copolymer latex having a glass transition temperature of -50 ° C to 20 ° C. More preferably, it is −50 ° C. to −10 ° C. By using the thing of this range, it becomes a coating layer which has cushioning properties suitable for gravure printing.

In the coating liquid of the present invention, various commonly used auxiliaries such as a dispersant, a water retention agent, an antifoaming agent, and a water-resistant agent may be used. As the auxiliary used in the present invention, an acrylic synthetic water retention agent and hydroxyethyl cellulose are preferably used, and an associative acrylic synthetic water retention agent is more preferably used. The associative acrylic synthetic water retention agent functions to improve the water retention of the coating solution and to reduce the high shear viscosity of the coating solution. Therefore, it is suitable for high-speed coating, the paint is not pushed into the coating base paper during coating, the coating layer on the base paper is bulky, and the cushioning property of the coating layer is improved. The rate tends to be low. Hydroxyethyl cellulose has the same effect. In addition, when using an acrylic synthetic water retention agent and / or hydroxyethyl cellulose, the blending amount is preferably 0.1 to 1.0 part by weight with respect to 100 parts by weight of the pigment.
As a method of applying a coating liquid containing a pigment and an adhesive prepared on the coating base paper, blade coater, bar coater, air knife coater, reverse roll coater, curtain coater, size press coater, gate roll coater, etc. Use one or two or more layers on the base paper. The coating amount range in which the present invention is effective is preferably 3 g / m ² or more and 25 g / m ² or less, more preferably 4 g / m ² or more and 16 g / m ² or less, more preferably 5 g / m ² per side. m ² or more and 16 g / m ² or less.

  As a method for drying the wet coating layer, various methods such as a steam superheating cylinder, a heated hot air air dryer, a gas heater dryer, an electric heater dryer, and an infrared heater dryer are used alone or in combination.

The coated paper coated and dried as described above is subjected to a smoothing process without performing a calendar process or using a super calendar, a high temperature soft nip calender, or the like. In the present invention, it is more effective to perform the calendar process, and the linear pressure of the calendar process is preferably 50 to 400 kN / m, more preferably 80 to 250 kN / m. The effect of the present invention is particularly excellent in a coated paper for gravure printing in which the basis weight of the coated paper is 40 g / m ² or more and 200 g / m ² or less, and the density is 0.40 to 1.50 g / cm ^3. More preferably, it is 0.40-1.20 g / cm < ³ >, More preferably, it is 0.40-1.15 g / cm < ³ >. The white paper glossiness of the coated paper is preferably 50% or more, more preferably 70% or more, and the effects of the present invention are more exhibited.
According to the present invention, it is possible to obtain a coated paper for gravure printing having a low density, a low dot loss rate, good gravure printing suitability, and excellent white paper gloss and smoothness. That is, when compared with the same blank paper glossiness, a low-density good gravure-coated paper can be obtained, and when compared with the same density, a gravure-coated paper with a higher blank paper glossiness is obtained. be able to.

  EXAMPLES The present invention will be specifically described below with reference to examples, but it is needless to say that the present invention is not limited to these examples. In addition, unless otherwise indicated, the part and% in an example show a weight part and weight%, respectively. In addition, it tested based on the evaluation methods as shown below about the coating liquid and the obtained coated paper for gravure printing.

<Evaluation methods>
(1) Density: Measured based on JIS P 8118.
(2) White paper glossiness: measured based on JIS P 8142.
(3) Smoothness: measured based on JIS P 8151.
(4) Halftone dot missing rate: Using a Ministry of Finance gravure monochrome printer, the halftone dot missing rate of coated paper printed at a printing speed of 40 m / min and a printing pressure of 10 kgf / cm was evaluated visually. A: Very good, B: Good, B: Slightly inferior, X: Inferior

<Surface treatment agent production example 1>
In a 1 L beaker, 267.4 g of ion-exchanged water, MOEDES (Equimolar adduct of dimethylaminoethyl methacrylate and dimethyl sulfate (effective weight 80% by weight), both reagents, Wako Pure Chemical Industries, Ltd.) 185.63 g (effective) 148.50 g), DMAAm (N, N-dimethylacrylamide, reagent, manufactured by Wako Pure Chemical Industries, Ltd.) 110.46 g, NK-14G (crosslinking agent, polyethylene glycol dimethacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd.) 0.415 g and V-50 (polymerization initiator, 2,2′-azobis (2-amidinopropane) dihydrochloride, manufactured by Wako Pure Chemical Industries, Ltd.) 0.952 g were mixed to obtain an aqueous monomer solution A. . Into a 5 L glass container, 1648 g of cyclohexane and 1.94 g of sugar ester S-770 (manufactured by Mitsubishi Kasei Co., Ltd.) as a dispersant were charged and dissolved uniformly at 60 ° C. over 1 hour. After dissolution, the mixture was cooled to 30 ° C. to obtain Dispersant Solution B.

  The monomer aqueous solution A is added to the dispersant solution B, set in a homomixer (ROBOMICS, manufactured by Tokki Kika Kogyo Co., Ltd.), and stirred at 9000 rpm for 4 minutes to obtain a monomer dispersion having an average particle size of 5 μm. . The whole amount was charged into a 5 L SUS tank equipped with a stirrer, a thermometer and a cooling tube, purged with nitrogen, heated, and polymerized at 55 ° C. for 1 hour. Further, after aging at 70 ° C. for 1 hour, a dehydrating tube with a cooling tube was attached, and 269 g of water was removed from the system over about 2 hours. As dehydration progressed, the temperature in the tank increased from 70 ° C to 90 ° C.

  Subsequently, the mixture was cooled to 40 ° C. or lower, and the contents were transferred to a stainless steel tray and dried with hot air at 80 ° C. to remove the solvent. Thus, white and granular cationic group-containing copolymer 1 was obtained. The cationic group-containing copolymer 1 used in the examples was lightly pulverized in a household coffee mill for about 1 second to obtain a cationic group-containing copolymer 1 having an average particle size of 4.0 μm.

<Surface treatment agent production example 2>
DADMAC (diallyldimethylammonium chloride, 65% aqueous solution, manufactured by Daiso Corporation) in a stainless steel kneader having two sigma-type stirring arms with an internal volume of 1 liter and externally circulating 70 ° C. oil in a jacket. 92 g (solid content 29.85 g), acrylamide (AAm, reagent, manufactured by Wako Pure Chemical Industries, Ltd.) 48.28 g, NK-14G (crosslinking agent, polyethylene glycol dimethacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd.) A monomer aqueous solution previously substituted with nitrogen consisting of 0214 g and 350 g of ion-exchanged water was added, and the monomer aqueous solution was heated while nitrogen gas was blown in for 20 to 40 minutes and nitrogen was substituted in the reaction system. Next, 0.22 g of V-50 was added as a polymerization initiator. The viscosity increased 15 minutes after the addition of the polymerization initiator, and the entire system became a soft gel after 1 hour. The polymerization was continued for 4 hours. The soot-like polymer was taken out and dried at 95 ° C. Then, it grind | pulverized with the coffee mill and the jet mill. The crushed crosslinked particles were classified with an ash volta to obtain a cationic group-containing copolymer 4. (Average particle size 45μm)

In accordance with Production Example 1 of a cationic group-containing copolymer, comparative monomer group-containing copolymers 2 (average particle size 6.2 μm) and 3 (average particle size 3.2 μm) with the monomer composition shown in Table 1 5 (average particle size 5.5 μm) and 6 (average particle size 4.5 μm) were produced.

[Example 1]
To 100 parts by weight of fine kaolin (Hyber gloss manufactured by Huber), 0.2 part of sodium polyacrylate as a dispersant was added as a dispersant and dispersed with a serie mixer to prepare a fine kaolin slurry having a solid content of 65%. . 10. 42 parts by weight of the fine kaolin slurry as a pigment, 58 parts by weight of a slurry having a solid content concentration of 75% of fine heavy calcium carbonate (FMT-97, manufactured by PMMA Tech) as a pigment, and latex (PA0466G, manufactured by A & L) 3 parts by weight and 2.7 parts by weight of starch (Mermaid 210 manufactured by Shikishima Starch Co., Ltd.) were added, and water was further added to obtain a coating solution having a solid content concentration of 66%.

As a filler, 9% by weight of light calcium carbonate per base paper weight, 100% kraft pulp as paper pulp, 75g / m ^{2 with} a basis weight of 0.70g / cm ³ , and a copolymer 1 Was coated on both sides with a rod metering size press coater so that the coating amount per side was 0.5 g / m ² , and dried to obtain a coated base paper.

The coated base paper surface-treated with the above coating solution was coated on both sides with a blade coater so that the coating amount per side was 15 g / m ² and dried.

  Subsequently, a super calendar process was performed at a roll temperature of 70 ° C. and a calendar linear pressure of 200 kN / m to obtain a coated paper for gravure printing.

[Example 2]
In Example 1, a coated paper for gravure printing was obtained in the same manner as in Example 1 except that the calender linear pressure was changed to 100 kN / m.
[Example 3]
In Example 1, a coated paper for gravure printing was obtained in the same manner as in Example 1 except that the coating amount of the copolymer 1 was changed to 0.1 g / m ² .
[Example 4]
In Example 1, a coated paper for gravure printing was obtained in the same manner as in Example 1 except that the coating amount of the copolymer 1 was changed to 0.1 g / m ² and the calender linear pressure was changed to 100 kN / m.

[Example 5]
In Example 1, a gravure-coated paper was obtained in the same manner as in Example 1 except that the copolymer 1 was changed to the copolymer 2 instead of the copolymer 1.
[Example 6]
In Example 1, a gravure-coated paper was obtained in the same manner as in Example 1 except that the copolymer 1 was changed to the copolymer 3 instead of the copolymer 1.
[Example 7]
In Example 1, a gravure-coated paper was obtained in the same manner as in Example 1 except that the copolymer 1 was changed to the copolymer 4 instead of the copolymer 1.

[Comparative Example 1]
In Example 1, the copolymer 1 was not applied to the base paper, but a coated paper for gravure printing was obtained in the same manner as in Example 1 except that.
[Comparative Example 2]
In Example 1, a gravure-coated paper was obtained in the same manner as in Example 1 except that starch (SK-20 manufactured by Nippon Corn Starch Co., Ltd.) was used instead of copolymer 1.

[Comparative Example 3]
In Example 1, a gravure coated paper was obtained in the same manner as in Example 1 except that the copolymer 1 was changed to the copolymer 5 instead of the copolymer 1.
[Comparative Example 4]
In Example 1, a gravure coated paper was obtained in the same manner as in Example 1 except that the copolymer 6 was used instead of the copolymer 1.

The above results are shown in Table 2.
From the results of Table 2, Examples 1 to 7 can obtain coated paper for gravure printing having a low density, a low dot loss rate, good gravure printing suitability, and excellent white paper gloss and smoothness. it can. Comparative Examples 1 to 4 have a higher density, a lower dot loss rate, and inferior smoothness than Examples 1 to 7.

Claims (7)

A coated paper for gravure printing in which a coating layer containing a pigment and an adhesive is provided on a base paper provided with a surface treatment agent, wherein the surface treatment agent is represented by the following general formula (I) At least one component (A) selected from a vinyl monomer and a vinyl monomer represented by the general formula (II), and a cationic group-containing vinyl monomer represented by the following general formula (III) And at least one component (B) selected from the cationic group-containing vinyl monomers represented by the general formula (IV): 97/3 to 30/70 as component (A) / component (B) A coated paper for gravure printing, comprising a cationic group-containing copolymer obtained by polymerization at a molar ratio.
[Wherein, R ¹ represents a hydrogen atom or a methyl group, and R ² and R ³ are the same or different and represent a hydrogen atom or a linear or branched alkyl group or alkenyl group having 1 to 4 carbon atoms. ]
[Wherein R ¹ represents the above-mentioned meaning, A ¹ and A ² are the same or different, and represent a group represented by the formula — (CH ₂ ) _n — (n represents an integer of 2 to 6). , B represents an —O— or —CH ₂ — group. ]
[R ¹ is as defined above, R ⁴ and R ⁵ are the same or different and each represents an alkyl group or alkenyl group having 1 to 4 carbon atoms, and R ⁶ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Y represents —O—, —NH— or —O—CH ₂ CH (OH) —, Z represents a linear or branched alkylene group having 1 to 4 carbon atoms, and X represents an acid. A conjugated base, a halogen atom or an alkyl sulfate group having 1 to 4 carbon atoms is shown. ]
[Wherein, R ⁷ and R ⁸ are the same or different and each represents a hydrogen atom or a methyl group; R ⁹ and R ¹⁰ are the same or different and each represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; Indicates meaning. ]   The cationic group-containing copolymer comprises a component (A), a component (B), and a component (C) of a crosslinkable vinyl monomer (provided that the monomer is represented by the general formula (IV)). The coated paper for gravure printing according to claim 1, which is obtained by polymerization of   3. The component (A) is at least one selected from (meth) acrylamide, N, N-dimethyl (meth) acrylamide and N, N-diethyl (meth) acrylamide. Coated paper for gravure printing.   The amount of the component (C) in the cationic group-containing copolymer is 0.0005 to 5 mol% in the total of the component (A), the component (B), and the component (C). Item 4. The coated paper for gravure printing according to Item 2 or 3.   The coated paper for gravure printing according to any one of claims 1 to 4, wherein the glossiness of the coated paper is 50% or more. 6. The gravure coated coated paper according to claim 1, wherein the coating amount of the surface treatment agent is 0.01 g / m ² or more and 3 g / m ² or less per side of the base paper. . The gravure according to any one of claims 1 to 6, wherein the coating amount of the coating layer containing the pigment and the adhesive is 3 g / m ² or more and 25 g / m ² or less per one side of the base paper. Coated paper for printing.