JP2007046218A - Coated paper for printing and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide coated paper for printing by coating a coating layer in contact with base paper according to a film transfer method and then forming at least one or more coating layers thereon and having excellent surface smoothness and printing suitability and to provide a method for producing the coated paper. <P>SOLUTION: The coated paper for printing is obtained by forming ≥2 coating layers on at least one surface of the base paper. The coating layer in contact with the base paper is coated by the film transfer method and the coating layer in contact with the base paper contains 55-100 mass% of delaminated kaolin having 2.0-5.0 μm average particle diameter d50<SB>1</SB>measured by a light scattering method, 0.35-0.55 μm average particle diameter d50<SB>2</SB>measured by a sedimentation method, ≥4 ratio (d50<SB>1</SB>/d50<SB>2</SB>) of the d50<SB>1</SB>to the d50<SB>2</SB>and the mass distribution of particles of ≤2μm measured by the sedimentation method and the mass distribution of particles of ≤0.3 μm measured by the sedimentation method within specific ranges as a pigment. Furthermore, a starch derivative as an adhesive is contained in an amount of 5-40 pts.mass based on 100 pts.mass of the pigment. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a coated paper for printing having two or more coating layers mainly composed of a pigment and an adhesive, and the coated layer in contact with the base paper contains a specific delaminated kaolin. The present invention relates to a coated paper for printing which is excellent in surface smoothness, white paper gloss, and printing suitability such as printing smoothness, which is applied by a film transfer method using a liquid, and a method for producing the same.

In general, coated paper for printing is manufactured by coating and drying a coating liquid mainly composed of a pigment and an adhesive on a base paper, and depending on the coating amount of the coating liquid and the finishing method of the coated paper, it can be cast coated. It is classified into paper, art paper, coated paper, finely coated paper, and the like. These coated papers are subjected to multicolor printing or single color printing, and are widely used as commercial printed materials such as flyers, brochures and posters, or as publications such as books and magazines. In recent years, with the progress of visualization and colorization of printed materials, there has been an increasing demand for higher quality coated paper for printing. Printing of blank paper quality such as blank paper glossiness, smoothness, whiteness, and printing smoothness, etc. Quality such as appearance in the finish is regarded as important.
In particular, flyers, pamphlets and the like among commercial printed materials have been required to have low cost and good print finishes for the purpose of advertising media. Therefore, the paper used is also becoming thinner and lighter.

  Conventional coated paper production methods include the off-machine method, in which papermaking and coating are performed in separate steps, and the on-machine method, in which papermaking and coating are performed simultaneously on a single machine. More efficient production is possible. Therefore, in general, as an equipment for producing lightweight coated paper, an on-machine method is adopted, and after paper making, a pigment coating solution is a film transfer type gate roll coater or rod or blade metering size press coater, It is produced by the fountain type short dwell blade coater.

  Conventionally, the surface of the coating liquid for the pigment coating liquid is sized to prevent the pigment coating liquid from being soaked into the base paper by sizing the surface coating liquid of the main starch formulation. When performing the coating, the coating of the primer coating liquid also serves as the starch surface size, so that the primer coating liquid penetrates into the base paper and the surface after the primer coating is sufficiently smooth. Therefore, it was necessary to increase the coating amount of the undercoat pigment coating solution.

On the other hand, for the purpose of obtaining higher-quality coated paper, multilayer coating has been conventionally used in which an undercoat coating solution containing an inexpensive pigment is applied and an overcoat coating solution is applied in consideration of blank paper quality and printing quality. Has been done. When all the multilayer coating is performed by the blade method, the highest surface smoothness and quality can be obtained. However, when manufacturing lightweight coated paper, considering the operability at the time of coating, it is not possible to reduce the base paper rice tsubo unlimitedly, and a certain amount of base paper rice tsubo is required, so the amount that can be coated is that much. Limited. However, when applying by a blade method, it is difficult to apply a coating amount of less than 6 g / m ² while maintaining sufficient surface smoothness.

  Conventionally, various methods for providing a pigment coating layer by a film transfer method have been proposed (see Patent Documents 1, 2, 3, 4, and 5). These mainly disclose means for solving mist and paint gum-up occurring at a coating speed of 1100 m / min or more. Also, a film transfer coating paint (see Patent Document 6) that exhibits excellent gloss and smoothness comparable to blade coating has been introduced. This is characterized by the use of a low-viscosity starch-based adhesive and the concentration of the pigment coating solution being as high as 58% or more, but because the starch-based adhesive used is low in viscosity, After application by the film transfer method, the starch-based adhesive may migrate in the coating layer, which may cause uneven printing.

Conventionally, delaminated kaolin has been used as a pigment used in the pigment coating layer, and coated paper containing delaminated kaolin with specified aspect ratio, particle diameter, etc. (see Patent Documents 7 to 9) Has been proposed. All of them are intended to obtain dull or matte coated paper that uses delaminated kaolin with a relatively large particle size and suppresses glossiness of blank paper, and the coating layer is one layer or two or more layers. However, the delaminated kaolin for the surface coating layer is blended, and the coating layer in contact with the base paper is not particularly considered.
The pigment particle diameter ratio (laser method / precipitation method) measured by the laser method and the sedimentation method was 3
. There has been proposed an offset printing coated paper (see Patent Document 10) in which a coating liquid containing an inorganic pigment in the range of 0 to 10 in an amount of 50 parts by weight or more per 100 parts by weight of pigment is applied to a base paper by a film transfer method. Yes. However, nothing is disclosed as to what kind of average particle size or particle size distribution is optimal for use in a coating layer in contact with a base paper in a multilayer coated paper.

Japanese Patent No. 3143899 Japanese Patent No. 2967723 Japanese Patent No. 2910030 Japanese Patent No. 3328554 Japanese Patent No. 3328922 Japanese Patent No. 2737897 JP-A-11-302998 JP 2002-105889 A JP 2002-194698 A JP 2005-89868 A

  In the present invention, a coating liquid containing a specific delaminated kaolin is applied by a film transfer method, and at least one pigment coating layer is provided on the coating liquid. The present invention provides a coated paper excellent in printing suitability such as printing smoothness and a manufacturing method thereof.

The printing coated paper of the present invention is a printing coated paper in which two or more coating layers mainly composed of a pigment and an adhesive are provided on at least one side of the base paper, and the coating layer in contact with the base paper is a film transfer system. The average particle diameter d50 ₁ measured by the light scattering method is within the range of 2.0 to 5.0 μm as the pigment, and the coating layer in contact with the base paper is the average particle diameter d50 measured by the sedimentation method. ₂ is in the range of 0.35 to 0.55 μm, the ratio of the average particle diameter d50 ₁ to the average particle diameter d50 ₂ (d50 ₁ / d50 ₂ ) is 4 or more, and the particle size distribution by the precipitation method The pigment contains delaminated kaolin in which the mass distribution of particles of 2 μm or less is in the range of 80 to 95% and the mass distribution of particles of 0.3 μm or less is in the range of 30 to 45%, Occupy delamine The weight ratio of the coated kaolin is 55 to 100% by mass, and the coating layer in contact with the base paper contains 5 to 40 parts by mass of a starch derivative as an adhesive per 100 parts by mass of the pigment. is there.
Moreover, it is preferable to contain 1 to 20 parts by mass of a copolymer latex having a particle diameter of 40 to 150 nm as an adhesive per 100 parts by mass of the pigment because the printing strength is further improved.
The outermost coating layer has, as a pigment, an average particle diameter d50 ₂ measured by a precipitation method in the range of 0.2 to 1.6 μm, and a particle diameter d90 corresponding to 90 cumulative mass% of the particle size distribution curve by the precipitation method. And the ratio of the average particle diameter d50 ₂ (d90 / d50 ₂ ) is in the range of 1 to 4.0, and the mass proportion of the kaolin in the pigment is 55 to 100% by mass. The surface smoothness, the ink inking property, and the printing smoothness are preferable because excellent effects are obtained.
Furthermore, the production method of the present invention for producing a coated paper for printing in which two or more coating layers mainly composed of a pigment and an adhesive are provided on at least one side of a base paper includes the following steps A and B: It is characterized by that.
Average as coated liquid for forming a coating layer in contact with the base paper, the average particle size d50 ₁ as measured by light scattering method is in the range of 2.0～5.0Myuemu, was determined by sedimentation method: Step A The particle diameter d50 ₂ is in the range of 0.35 to 0.55 μm, the ratio of the average particle diameter d50 ₁ to the average particle diameter d50 ₂ (d50 ₁ / d50 ₂ ) is 4 or more, and the precipitation method In the particle size distribution curve according to the above, a delaminated kaolin in which the mass distribution of particles of 2 μm or less is in the range of 80 to 95% and the mass distribution of particles of 0.3 μm or less is in the range of 30 to 45%, A process for preparing a dispersion having a mass ratio of 55 to 100% by mass of the delaminated kaolin in the pigment and 5 to 40 parts by mass of a starch derivative per 100 parts by mass of the pigment as an adhesive. Step and Step B: A step of coating the coating liquid prepared in Step A on at least one side of the base paper by a film transfer method.
In the production method of the present invention, when the starch derivative is used in a small amount, it is preferable to add a thickener or a water retention agent, and in that case, 0.01 to 1.0 mass per 100 parts by mass of the pigment. It is preferable to adjust within the range of parts.
In the method of the present invention, the outermost coating layer is, as a pigment, an average particle diameter d50 ₂ as measured by sedimentation method is in the range of 0.2～1.6Myuemu, 90 of the particle size distribution curve by sedimentation method The ratio of the particle diameter d90 corresponding to the cumulative mass% and the ratio (d90 / d50 ₂ ) of the average particle diameter d50 ₂ is kaolin in the range of 1 to 4.0, and the mass ratio of the kaolin in the pigment Is preferably 55 to 100% by mass and includes a step of preparing a dispersion containing an adhesive and a step of applying the coating solution by a blade method.

  The printing coated paper according to the present invention is excellent in surface smoothness and printability such as ink inking property and printing smoothness, even though the coating layer in contact with the base paper is coated by a film transfer method. Has excellent characteristics.

In coated paper for printing according to the present invention, delaminated kaolin contained in the coating layer in contact with the base paper has an average particle size d50 ₁ as measured by light scattering method is in the range of 2.0~5.0μm The average particle diameter d50 ₂ measured by the sedimentation method is in the range of 0.35 to 0.55 μm, and the ratio (d50 ₁ / d50 ₂ ) of the average particle diameter d50 ₁ to the average particle diameter d50 ₂ is 4 or more. In the particle size distribution curve by the sedimentation method, the mass distribution of particles of 2 μm or less is in the range of 80 to 95%, and the mass distribution of particles of 0.3 μm or less is in the range of 30 to 45%. It needs to be a ted kaolin. When the delaminated kaolin having such physical properties is formed as a coating layer in contact with the base paper by a film transfer method using the coating liquid containing this, the pigment is uniformly applied to the surface of the base paper, and the covering property is improved. Greatly improved.
In the present invention, the content of the delaminated kaolin in the pigment needs to be 55 to 100% by mass, and the content of the delaminated kaolin is more preferably 65 to 100% by mass. When the delaminated kaolin content is less than 55% by mass of the total pigment, the improvement in smoothness is insufficient.

Delaminated kaolin is a clay mineral obtained by peeling a layered bulk kaolin into a single layer, and has a large aspect ratio.
In general, the individual shape characteristics of tabular grains such as delaminated kaolin can be defined by the ratio (aspect ratio d / t) to the major axis d thickness t. In the present invention, the delaminated kaolin The granular characteristics are defined by the average particle diameter d50 ₁ by the light scattering method and the average particle diameter d50 ₂ by the sedimentation method.
In the light scattering method average particle size d50 ₁ measurement by the contrast its diameter is regarded all individual particles to spherical particles are measured, the average particle size d50 ₂ measured by sedimentation method, particle shape sedimentation In order to affect the property, particles having a flat plate shape and slower sedimentation are measured as particles having a smaller apparent diameter. Therefore, it is considered that the ratio of the average particle diameter d50 ₁ by the light scattering method and the average particle diameter d50 ₂ by the precipitation method, d50 ₁ / d50 ₂ , increases as the above-described aspect ratio increases. In the present invention, a laser diffraction particle size distribution measuring device SALD-2000 (manufactured by Shimadzu Corporation) is used as a method for measuring the average particle size by the light scattering method, and Cedy is used as a method for measuring the particle size distribution and the average particle size by the precipitation method. Graph 5100 (manufactured by Micromeritics) was used.

By the way, in the particle size distribution of the delaminated kaolin measured by the sedimentation method, when the mass distribution of particles of 2 μm or less is less than 80% and the mass distribution of particles of 0.3 μm or less is less than 30%, a component having a large particle size is present. In many cases, it is not preferable because the smoothness of the coating layer is lowered. When the mass distribution of particles of 2 μm or less exceeds 95% and the mass distribution of particles of 0.3 μm or less exceeds 45%, there are many components having a small particle size. The aqueous coating solution using this pigment is not preferable because it excessively penetrates into the base paper and reduces the smoothness of the coating layer.
Further, when the average particle size d50 ₁ and the average particle size d50 ₂ are less than 2.0 μm and less than 0.35 μm, respectively, the delaminated kaolin in the coating solution excessively penetrates into the base paper. It becomes difficult to form a coating layer with high smoothness. Further, when the average particle diameter d50 ₁ and the average particle diameter d50 ₂ exceed 5.0 μm and 0.55 μm, respectively, it is difficult to obtain a coated paper having sufficient white paper gloss.
Even when d50 ₁ / d50 ₂ is less than 4, it is difficult to obtain a coated paper for printing intended by the present invention. In the present invention, the value of d50 ₁ / d50 ₂ is preferably 4 to 12, and more preferably 5 to 11.

In the present invention, the pigment component is composed of 55 to 100% by mass of the specific delaminated kaolin and other pigments of 45% by mass or less.
Examples of such other pigments include pigments used in the ordinary coated paper field, specifically, heavy or light calcium carbonate, kaolin (excluding the above specific delaminated kaolin), satin white, and calcined kaolin. , Inorganic pigments such as talc, calcium sulfate, barium sulfate, aluminum hydroxide, titanium dioxide, zinc oxide, alumina, magnesium carbonate, magnesium oxide, silica, magnesium aluminosilicate, calcium silicate, bentonite, zeolite, sericite, smectite, Organic pigments such as solid type, hollow type, through-hole type plastic pigments, binder pigments, etc. are listed. Depending on the target coated paper quality, one or more types can be selected and used. To do.

In order to develop the surface strength of the coated paper of the present invention, it is essential to use a starch derivative that is a water-soluble adhesive as an adhesive for the coating layer in contact with the base paper. A water-dispersible adhesive can also be used in combination.
Examples of the starch derivative include oxidized starch, esterified starch, etherified starch, dextrin, and cold water-soluble starch. As the compounding quantity, 5-40 mass parts per 100 mass parts of pigments are required, and it is preferable to mix | blend in the ratio of 10-30 mass parts. Incidentally, when the blending amount of the starch derivative is less than 5 parts by mass, when the coating liquid is transferred to the base paper, the immobilization of the paint becomes too fast and it is not transferred well to the base paper, and the paint residue remains on the roll, and the roll stains. appear. On the other hand, when the amount exceeds 40 parts by mass, the viscosity of the paint excessively increases, the paper separation at the exit of the application nip is not stable, and unevenness having a certain pattern occurs on the surface of the base paper.

  In the present invention, examples of other water-soluble adhesives that can be used in combination with starch derivatives include proteins such as casein, soybean protein, and synthetic proteins, cellulose derivatives such as hydroxyethyl cellulose, polyvinyl alcohol, and modified products thereof. When a water-soluble adhesive other than the starch derivative is used in combination, it is desirable that the total amount of the starch derivative and the other water-soluble adhesive is 40 parts by mass or less per 100 parts by mass of the pigment.

  Examples of the water-dispersible adhesive used in the present invention include conjugated diene copolymer latexes such as styrene-butadiene copolymer latex, methyl methacrylate-butadiene copolymer latex, and styrene-methyl methacrylate-butadiene copolymer latex. Acrylic polymer latex such as acrylic ester and / or methacrylic ester polymer or copolymer latex, vinyl polymer latex such as ethylene-vinyl acetate polymer latex, or carboxyl of these various polymer latexes Examples thereof include a polymer or copolymer latex modified with a functional group-containing monomer such as a group, and among these, those having an average particle diameter of 40 to 150 nm are preferable. With the same content, the smaller the average particle diameter of the latex, the larger the contact area with the pigment in the coating layer, and the strength of the coating layer can be effectively expressed. By the way, if the particle size of the water-dispersible adhesive is smaller than 40 nm, wetting surface strength due to dampening water during offset printing, even in the pigment coating layer in contact with the base paper, due to the effect of the emulsifier compounded at the time of latex production Is not preferable. Further, when the particle diameter of the latex exceeds 150 nm, the contact area with the pigment in the coating layer is decreased at the same content, and thus the effect of improving the surface strength may be insufficient. The amount of the water-dispersible adhesive contained in the pigment coating solution for forming the coating layer in contact with the base paper is 1 to 20 parts by mass, preferably 5 to 15 parts by mass per 100 parts by mass of the pigment. You can choose.

  In the present invention, when the coating liquid for forming the coating layer in contact with the base paper has only a low water retention performance, for example, even if the blending amount of the starch derivative is 5 parts by mass or more with respect to 100 parts by mass of the pigment When the coating liquid is transferred to the base paper at the time of coating, the moisture of the coating liquid is quickly absorbed by the paper, and therefore the coating liquid on the roll is solidified and is difficult to peel off from the roll. There is a risk of contamination. In order to prevent this, it is preferable to contain at least one thickener or water retention agent in the coating solution of the coating layer in contact with the base paper. As the thickener or water retention agent preferably used in the present invention, an alkali thickening type such as polycarboxylic acid or acrylic copolymer, an acrylic polymer or a hydrophilic base polymer such as polyethylene oxide is used at both ends. Naturally derived types such as an association type having an oil group, carboxymethylcellulose, sodium alginate and the like can be mentioned, and an acrylic copolymer emulsion is preferably used particularly from the viewpoint of workability and cost. As a compounding quantity of a thickener or a water retention agent, the range of 0.01-1.0 mass part is preferable with respect to 100 mass parts of pigments, More preferably, it is the range of 0.05-0.8 mass part.

  In addition to thickeners and water-retaining agents, the coating solution used to form the coating layer in contact with the base paper contains blue or purple dyes, colored pigments, fluorescent dyes, and antioxidants as necessary. Various auxiliaries such as an agent, an anti-aging agent, a conductive inducer, an antifoaming agent, an ultraviolet absorber, a dispersant, a pH adjuster, a mold release agent, a water-resistant agent, and a water repellent can be appropriately blended.

  In the present invention, the solid content of the coating liquid containing the specific delaminated kaolin, other pigments used in combination as necessary, an adhesive such as a starch derivative, and various auxiliary agents used as necessary. A density | concentration can be selected in 25-65 mass%. In consideration of adjustment of coating amount and operability, it is desirable to be in the range of 30 to 55% by mass.

The dry coating amount of the coating layer in contact with the base paper of the present invention is preferably 0.5 to 15.0 g / m ² per side. Incidentally, when the coating amount is less than 0.5 g / m ² , the surface coverage of the paint is inferior, and the desired quality cannot be obtained. On the other hand, if it exceeds 15.0 g / m ² , the surface coverage is improved, but when a coating layer containing a pigment and an adhesive is formed thereon by blade coating, streak defects called streaks occur. The quality of the coated paper may be significantly impaired.

The base paper used in the present invention is not particularly limited, and the base paper used in conventional coated paper for printing can be used.
Examples of the pulp component constituting the base paper include bleached chemical pulp such as commonly used bleached hardwood pulp (LBKP) and bleached softwood pulp (NBKP), groundwood pulp (GP), pressurized groundwood pulp (PGW), and refiner. Mechanical pulp such as groundwood pulp (RGP) and thermomechanical pulp (TMP), deinked waste paper pulp (DIP), waste paper, and the like are appropriately mixed and used. The amount of mechanical pulp preferably does not exceed 70% by mass of the total pulp constituting the base paper. If it exceeds 70% by mass, printability such as print smoothness and surface strength of the finally obtained coated paper may be impaired. Moreover, 1 type, or 2 or more types, such as a pulp fiber obtained from non-wood fiber raw materials, such as kenaf, a synthetic pulp, an inorganic fiber, can also be mix | blended with a base paper.
Mechanical pulp and deinked waste paper pulp can be bleached and used as necessary, and the degree of bleaching can be arbitrarily performed.
For bleaching pulp, it is preferable to use a bleaching process that does not use molecular chlorine such as chlorine gas or chlorine compounds such as chlorine dioxide from the viewpoint of environmental conservation. Pulp that has undergone such bleaching process is used. Examples thereof include ECF pulp and TCF pulp.

Examples of fillers added to the base paper include heavy calcium carbonate, light calcium carbonate, calcium sulfite, gypsum, talc, clay, calcined kaolin, white carbon, amorphous silica, delaminated kaolin, diatomaceous earth, and magnesium carbonate. Examples include inorganic pigments such as titanium dioxide, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, and zinc hydroxide, and organic pigments such as urea / formalin resin fine particles and fine hollow particles, and are included in waste paper and waste paper. The filler can also be reused. Two or more fillers can be used in combination.
The blending amount of the filler is generally added so that the paper (base paper) ash content is in the range of 3 to 20% by mass.

  In addition to pulp and filler in the base paper, internal additives for papermaking such as internal sizing agent, anionic, nonionic, cationic or amphoteric yield improver, drainage improver, paper strength enhancer, etc. Can be added as needed. Specific examples of the internal sizing agent include sizing agents such as alkyl ketene dimer, alkenyl succinic anhydride, styrene-acrylic, higher fatty acid, petroleum resin, and rosin. Specific examples of yield improvers, drainage improvers, and paper strength enhancers include, for example, polyvalent metal compounds such as aluminum (specifically, sulfate bands, aluminum chloride, sodium aluminate, basic aluminum compounds). Etc.), various starches, polyacrylamide, urea resin, polyamide / polyamine resin, polyethyleneimine, polyamiin, polyvinyl alcohol, polyethylene oxide and the like. Moreover, it is also possible to use a bulking agent and a softening agent having a function of inhibiting the binding between pulp fibers as long as the desired effect of the present invention is not hindered. Specific examples of bulking agents and softeners include, for example, ester compounds of polyhydric alcohols and fatty acids, polyoxyalkylene compounds of polyhydric alcohols and fatty acid ester compounds, fatty acid polyamidoamines, polyhydric alcohol surfactants, An ionic surfactant etc. can be illustrated. The amount of the bulking agent and softening agent is generally about 0.05 to 2.0% by mass with respect to the pulp.

There are no particular limitations on the paper making conditions of the base paper, and for example, commercial scale paper machines such as long net paper machines, gap former paper machines, round net paper machines, short net paper machines, etc. It can be appropriately selected and used. The papermaking method may be any method such as acidic papermaking, neutral papermaking, or weak alkali papermaking. However, in recent years, since paper preservation is required, base paper made by neutral papermaking is preferred. The base paper can be subjected to normal size press treatment or pigment size press treatment, and starch derivative, polyvinyl alcohol, polyacrylamide or the like is appropriately used as an adhesive for such size press treatment. The basis weight of the base paper made under these paper making conditions is preferably 35 to 70 g / m ² .

  In the production method of the present invention, the coating liquid for forming the coating layer in contact with the base paper is applied by a film transfer type coating apparatus. As a film transfer type coating apparatus, a gate roll coater, a blade metering size press coater, a rod metering size press coater, or the like can be used.

  In the coated paper of the present invention, one or more coating layers mainly composed of a pigment and an adhesive are applied on the coating layer in contact with the base paper. Examples of such pigments include, but are not limited to, calcium carbonate, calcined kaolin, structural kaolin, delaminated kaolin, talc, calcium sulfate, barium sulfate, aluminum hydroxide, titanium dioxide, zinc oxide, alumina, Inorganic pigments such as magnesium carbonate, magnesium oxide, silica, magnesium aluminosilicate, calcium silicate, bentonite, zeolite, sericite, smectite, organic pigments such as solid type, hollow type, through-hole type plastic pigments, binder pigments, etc. It is possible to use pigments used in the ordinary coated paper field. Among these pigments, one or more types are appropriately selected and used according to the level of white paper gloss required for the target coated paper.

Among the coating layers formed on the coating layer in contact with the base paper, the following pigments are preferably used for the outermost coating layer. That is, the average particle diameter d50 ₂ measured by the precipitation method is in the range of 0.2 to 1.6 μm, and the particle diameter d90 corresponding to 90 cumulative mass% of the particle size distribution curve by the precipitation method and the average particle diameter d50 ₂ It is preferable to use kaolin having a ratio (d90 / d50 ₂ ) of 1 to 4.0. So long as the average particle diameter d50 ₂ is 0.2～1.6Myuemu, excellent effects by the surface smoothness and sheet gloss is obtained, more preferably 0.2～1.4Myuemu.

Further, d90 / d50 _2, which is the ratio of the 90% particle size d90 to the average particle size d50 ₂ , is an index value indicating the breadth of the particle size distribution of the pigment, and the value is substantially 1 or more. The closer the value is, the closer to monodispersion and the narrower the particle size distribution, and the larger the value, the wider the particle size distribution. In the present invention, the closer the d90 / d50 ₂ value is to 1, the more the orientation of kaolin in the outermost coating layer is promoted and the surface smoothness of the coated paper is improved, while the d90 / d50 ₂ value is 4 If it exceeds 0.0, the orientation effect of kaolin is small, and the effect of improving the surface smoothness of the coated paper may be small. Moreover, More preferably, it is 1-3.5.

  In the present invention, the kaolin content in the pigment of the outermost coating layer is preferably in the range of 55 to 100 parts by mass, and more preferably in the range of 60 to 100 parts by mass. When the kaolin content is 55 parts by mass or more, the smoothness improving effect by the kaolin is increased.

  Generally, in a coated paper for printing in which two or more coating layers are provided on at least one side of a base paper, from the viewpoint of cost effectiveness, the coating layer is composed of a coating layer in contact with the base paper and a single layer formed thereon. In many cases, it has a two-layer structure composed of coating layers. When the coating layer has a two-layer structure as described above, the outermost coating layer is directly formed on the coating layer in contact with the base paper, and therefore the specific kaolin described above is used for the outermost coating layer. The effect of improving the smoothness of the ink is remarkable, and more excellent effects can be exhibited in the surface smoothness, the ink inking property and the printing smoothness.

  In addition, in the coated paper for printing having three or more layers on at least one side of the base paper, the pigment and the adhesive used for the intermediate layer between the coating layer in contact with the base paper and the outermost coating layer are particularly limited. In general, raw materials used in the field of coated paper can be used, and the amounts of pigments, adhesives and auxiliaries are not particularly limited, and are within the range of amounts normally used in the field of coated paper. Can be used in

The adhesive of the outermost coating layer is not particularly limited, and is an adhesive used in the ordinary coated paper field, for example, various starches such as oxidized starch, esterified starch, cold water soluble starch, and casein. , Proteins such as soybean protein and synthetic protein, cellulose derivatives such as carboxymethylcellulose and methylcellulose, water-soluble adhesives such as polyvinyl alcohol and its modified products, styrene-butadiene copolymer, methylmethacrylate-butadiene copolymer It is possible to use vinyl polymer latex such as conjugated diene polymer latex, acrylic polymer latex, ethylene-vinyl acetate copolymer, etc. Two or more types can be appropriately selected and used.
Further, the amount of the adhesive is not particularly limited, but is 5 to 20 parts by mass, preferably 8 to 15 parts by mass per 100 parts by mass of the pigment.

  In the present invention, the coating solution for the outermost coating layer includes, as necessary, a blue or purple dye or a colored pigment, a fluorescent dye, a thickening water retention agent, an antioxidant, an anti-aging agent, Various auxiliary agents such as a conductivity-inducing agent, an antifoaming agent, an ultraviolet absorber, a dispersant, a pH adjuster, a mold release agent, a water-resistant agent, and a water-repellent agent can be appropriately blended.

  Moreover, although the solid content concentration of the coating liquid containing the above-mentioned pigment, adhesive, and various auxiliary agents used as necessary can be selected in the range of 40 to 75% by mass, in consideration of operability. It is preferable that it is the range of 45-70 mass%.

  In coating the coating liquid on the coating layer in contact with the base paper, for example, a blade coater, an air knife coater, a roll coater, a reverse roll coater, a bar coater, a curtain coater, a die slot coater, a gravure coater, a Chanplex A blade that provides excellent surface smoothness, although coating devices commonly used in the production of coated paper such as coaters, two-roll size press coaters, gate roll size press coaters, and film metering size press coaters can be used. A coater is most preferably used.

The dry coating amount of the coating layer applied on the coating layer in contact with the base paper is adjusted in the range of 5.0 to 20.0 g / m ² per side. Even when two or more coating layers are overcoated, the dry coating amount per layer may be adjusted within this range.

  The coated paper thus obtained is passed through various publicly known finishing devices such as a super calender, gloss calender, soft calender, etc., and finished with a product.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In addition, unless otherwise indicated, the part and% in an example show a mass part and the mass%, respectively. Moreover, the addition amount of the used chemical | medical agent shows the mass part of solid content conversion.

The physical properties of kaolin used in Examples and Comparative Examples were measured by the methods described below, and the results are shown in Tables 1 and 2.
(Measurement of average particle diameter of pigments by light scattering method)
The particle size distribution of the pigment was measured using a laser diffraction particle size distribution analyzer SALD-2000 manufactured by Shimadzu Corporation, and the average particle size (d50 ₁ ) corresponding to 50 cumulative mass% was measured. The pigment dispersion used for the measurement is a region where a pigment slurry having a solid content concentration of 5% by mass prepared by adding 0.05% of a dispersant (sodium polyacrylate) to the pigment can be measured with the measuring device. Obtained by diluting up to

(Pigment particle size distribution and average particle size measurement by sedimentation method)
The particle size distribution of the pigment was measured using a Sedigraph 5100 manufactured by US Micromeritics, and the average particle size (d50 ₂ ) corresponding to 50 cumulative mass% and the particle size corresponding to 90 cumulative mass% (d90 ) Was measured. Further, from the particle size distribution curve, the mass distribution of particles of 2 μm or less and the mass distribution of particles of 0.3 μm or less were obtained. The pigment dispersion used for the measurement was prepared by adding a pigment slurry having a solid content concentration of 5% by mass prepared by adding 0.05% of a dispersant (sodium polyacrylate) to a pigment, solubilizing pyrophosphate salt (trade name: Nankaline). It was obtained by diluting with a 0.1% aqueous solution (S1, manufactured by Rin Chemical Co., Ltd.) so that the pigment solid content concentration was about 1%, and subjected to ultrasonic dispersion treatment (30 W, 45 kHz, 60 minutes).
The coated papers for printing obtained in the examples and comparative examples described later were evaluated by the following methods, and the results are shown in Table 1. The following evaluation test was performed in an environment of 23 ° C. and a relative humidity of 50%.

  The coated papers for printing obtained in Examples and Comparative Examples described later were evaluated by the following methods, and the results are shown in Tables 1 and 2. The following evaluation test was performed in an environment of 23 ° C. and a relative humidity of 50%.

(White paper gloss)
It measured using the 75 degree glossiness meter according to ISO 8254-1 (1999), and calculated | required the average value.

(PPS smoothness of coated paper)
Using a Parker Print Surf (PPS) surface smoothness tester (model name: MODEL M-569, manufactured by MESSMER BUCHEL, UK), backing disk: soft rubber, clamp pressure: 0.98 MPa, 5 times smoothness measurement The average value was calculated.
In addition, it is preferable that the PPS smoothness in the coated paper after the outermost coating layer is coated and calendered is less than 0.9.

(Printability (ink fillability and print smoothness))
In an RI printing machine (Meiji Seisakusho), printing was performed using 0.1 cc of printing ink (Values-G type, manufactured by Dainippon Ink & Chemicals, Inc.), transferred ink density (ink fillability), and The transfer uniformity (printing smoothness) of the ink was visually observed and comprehensively evaluated.
A: Printability is particularly excellent.
○: Printability is excellent.
Δ: Printability is slightly inferior.
X: Printability is inferior.

(Surface printing strength)
With a RI printer (Meiji Seisakusho), 0.4 cc of printing ink (paper test SD50 red BT = 13, manufactured by T & K TOKA) is spread on the roll, and the transfer speed is slowed down on the coated paper to be evaluated. After transferring the ink and printing, knead the ink without wiping off the ink on the roll, overprint it on the coated paper once printed, then knead the ink again without wiping off the ink on the roll. Overprinting was performed on the coated paper that had been printed once, and overprinted three times for convenience. Thereafter, the peeled state of the paper surface present in the ink remaining on the roll was transferred to another paper, and the color loss state of the transferred ink was visually evaluated.
A: No color loss.
'': Color loss is slightly observed, but it is a good level as coated paper.
○: Slight color loss is recognized, but it is a practical level as coated paper.
Δ: Color loss is observed.
X: The color is remarkably lost.

(Suitability for film transfer coating)
When coating the coating solution for the coating layer in contact with the base paper using a rod metering size press coater, the roll dirt was visually observed and comprehensively evaluated. In addition, evaluation above (circle) is a practical use level.
A: Coating suitability is particularly excellent.
○: Excellent coating suitability.
Δ: poor coating suitability
X: Coating is impossible.

Example 1
(Preparation of coating solution for coating layer in contact with base paper)
In an aqueous solution in which 0.1 part of sodium polyacrylate as a dispersant is added to kaolin to be dispersed, the average particle diameter d50 ₁ measured by the light scattering method is 3.6 μm, and the average particle diameter d50 ₂ measured by the precipitation method. Is 0.47 μm, d50 ₁ / d50 ₂ is 7.7, the particle size distribution curve by sedimentation method has a mass distribution of particles of 2 μm or less of 90%, and a mass distribution of particles of 0.3 μm or less is 35%. 100 parts of laminated kaolin (trade name: Conzer 2000, manufactured by Imeris Co., Ltd.) was dispersed with a Coreless disperser to prepare a pigment slurry. To this slurry, 25 parts of oxidized starch (trade name: Ace B, manufactured by Oji Cornstarch Co., Ltd.), styrene-butadiene copolymer latex (trade name: Smartex PA2323, particle size: 89 nm) as an adhesive with respect to 100 parts of pigment. (Manufactured by Nippon A & L Co., Ltd.) was sequentially added to finally prepare a coating solution having a solid concentration of 50%.

(Preparation of coating solution for outermost coating layer)
As the pigment component, an average particle diameter d50 ₂ is 0.40μm as measured by sedimentation method, d90 is 1.75 [mu] m, kaolin d90 / d50 ₂ is 4.4 (trade name: Kaogurosu 90, seals Ltd.) and 70 parts of To a pigment slurry consisting of 30 parts of heavy calcium carbonate having an average particle size of 0.8 μm (trade name: Hydrocurve 90, manufactured by Bihoku Flour Industries), oxidized starch (trade name: Oji Ace B) with respect to 100 parts of pigment. 2 parts, manufactured by Oji Cornstarch Co., Ltd., 12 parts of styrene-butadiene copolymer latex (trade name: SMARTEX PA2323, particle size: 89 nm, manufactured by Nippon A & L Co., Ltd.), and auxiliary agents such as antifoaming agent and dye are added. Finally, a coating solution having a solid content concentration of 59% was prepared.

(Create coated paper for printing)
Apply a coating solution for the coating layer in contact with the base paper obtained above to a high-quality base paper (rice basis weight 44 g / m ² ) with a tenacity of 0.67 g / cm ³ per side using a rod metering size press coater. An undercoat layer was formed by coating on both sides so that the dry coating amount of was 4 g / m ² and drying. Next, the coating liquid for the outermost coating layer obtained above was applied to each of the undercoat layers using a blade coater and dried so that the dry coating amount per side became 10 g / m ^2. The outermost coating layer was provided on both sides. The coated paper thus obtained was passed through a super calender under conditions of a temperature of 70 ° C. and a linear pressure of 200 kN / m to obtain a coated paper for printing.

Example 2
In the preparation of the coating solution for the coating layer in contact with the base paper of Example 1, 90 parts of delaminated kaolin (trade name: Conzer 2000) as a pigment component and heavy calcium carbonate having a mean particle size of 0.8 μm (trade name: 10 parts hydro curve 90, manufactured by Bihoku Flour Chemical Co., Ltd., 15 parts by weight of oxidized starch (trade name: Oji Ace B), styrene-butadiene copolymer latex (trade name: Smartex PA2323) A coated paper for printing was obtained in the same manner as in Example 1 except that the blending amount was 10 parts.

Example 3
In the preparation of the coating solution for the coating layer in contact with the base paper of Example 2, styrene-butadiene copolymer latex (trade name: SN-113I, instead of styrene-butadiene copolymer latex (trade name: SMARTEX PA2323), A coated paper for printing was obtained in the same manner as in Example 2 except that particle diameter: 190 nm, manufactured by Nippon A & L Co., Ltd. was used.

Example 4
In the preparation of the coating solution for the coating layer in contact with the base paper of Example 1, 60 parts of delaminated kaolin (trade name: Conzer 2000) as a pigment component and light calcium carbonate having an average particle size of 0.39 μm (Brilliant S-15) 40 parts of Shiraishi Kogyo Co., Ltd., 15 parts of oxidized starch (trade name: Oji Ace B) as an adhesive component, styrene-butadiene copolymer latex (trade name: SMARTEX PA2182-2, particle size: 100 nm) (Manufactured by Nippon A & L Co., Ltd.) Coated paper for printing was obtained in the same manner as in Example 1 except that 12 parts were used.

Example 5
In the preparation of the coating layer for a coated liquid in contact with the base paper of Example 1, delaminated kaolin (trade name: contour 2000) instead of an average particle size d50 ₁ as measured by light scattering method 2.1 .mu.m, sedimentation The average particle diameter d50 ₂ measured by the method is 0.47 μm, d50 ₁ / d50 ₂ is 4.5, and the particle size distribution curve by the sedimentation method has a mass distribution of particles of 2% or less of 92% and particles of 0.3 μm or less. 100 parts of delaminated kaolin (trade name: Conzer 2070, manufactured by Imeris Co., Ltd.) having a mass distribution of 34%, 15 parts of oxidized starch (trade name: Oji Ace B) as an adhesive component, and styrene-butadiene A coated paper for printing was obtained in the same manner as in Example 1, except that 10 parts of copolymer latex (trade name: Smartex PA2323) was used.

Example 6
In the preparation of the coating solution for the coating layer in contact with the base paper of Example 5, 100 parts of delaminated kaolin (trade name: Conzer 2070) was used, and oxidized starch (trade name: Oji Ace B) 15 as an adhesive component. Part and 10 parts of a styrene-butadiene copolymer latex (trade name: SMARTEX PA2323), and 0.04 part of an acrylic copolymer emulsion (trade name: Somalex 350, manufactured by Somaru) as a water retention agent component. A coated paper for printing was obtained in the same manner as in Example 5 except that it was used.

Example 7
In the preparation of the coated liquid for the outermost coating layer of Example 2, kaolin (trade name: Kaogurosu 90) instead of the average particle diameter d50 ₂ is 1.14μm as measured by sedimentation method, d90 is 1.90μm , kaolin d90 / d50 ₂ is 1.7 (trade name: Astra plus, manufactured by Imerys, Inc.) was used instead got coated paper for printing in the same manner as in example 2.

Example 8
In the preparation of the coated liquid for the outermost coating layer of Example 2, kaolin (trade name: Kaogurosu 90) instead of the average particle diameter d50 ₂ is 0.48μm as measured by sedimentation method, d90 is 1.34μm , d90 / d50 ₂ kaolin 2.8 (trade name: para printed, manufactured PPSA Inc.) were used in place to obtain a coated paper for printing in the same manner as in example 2.

Example 9
In the preparation of the coated liquid for the outermost coating layer of Example 2, kaolin (trade name: Kaogurosu 90) instead of the average particle diameter d50 ₂ is 0.24μm as measured by sedimentation method, d90 is 0.74μm , d90 / d50 ₂ is kaolin is 3.1 (trade name: Hydra gross 90, manufactured by Huber Corporation) was used instead got coated paper for printing in the same manner as in example 2.

Example 10
In the preparation of the coated liquid for the outermost coating layer of Example 2, kaolin (product name: Kaogurosu 90) instead of the average particle diameter d50 ₂ is 0.95μm as measured by sedimentation method, d90 is 3.21μm , d90 / d50 ₂ is kaolin is 3.4 (trade name: Capim NP, manufactured by Imerys, Inc.) was used instead got coated paper for printing in the same manner as in example 2.

Example 11
In the preparation of the coated liquid for the outermost coating layer of Example 2, kaolin (trade name: Kaogurosu 90) instead of the average particle diameter d50 ₂ is 0.53μm as measured by sedimentation method, d90 is 2.13μm , d90 / d50 ₂ is kaolin is 4.0 (trade name: contrast 300, manufactured by Engelhard Corporation) were used in place to obtain a coated paper for printing in the same manner as in example 2.

Example 12
In the preparation of the coated liquid for the outermost coating layer of Example 2, kaolin (trade name: Kaogurosu 90) instead of the average particle diameter d50 ₂ is 1.69μm as measured by sedimentation method, d90 is 5.32μm , d90 / d50 ₂ is kaolin is 3.2 (trade name: Mirana 950, manufactured by Engelhard Corporation) were used in place to obtain a coated paper for printing in the same manner as in example 2.

Example 13
In the preparation of the coated liquid for the outermost coating layer of Example 2, kaolin (trade name: Kaogurosu 90) instead of the average particle diameter d50 ₂ is 0.18μm as measured by sedimentation method, d90 is 0.46μm , d90 / d50 ₂ kaolin 2.5 (trade name: Japan gloss, manufactured by Huber Corporation) were used in place to obtain a coated paper for printing in the same manner as in example 2.

Example 14
In the preparation of the coated liquid for the outermost coating layer of Example 7, the pigment component, an average particle diameter d50 ₂ is 1.14μm as measured by sedimentation method, d90 is 1.9 .mu.m, d90 / d50 ₂ is 1. A coated paper for printing was obtained in the same manner as in Example 7, except that 100 parts of kaolin 7 (trade name: Astraplus) was used.

Example 15
In the preparation of the coated liquid for the outermost coating layer of Example 7, the pigment component, an average particle diameter d50 ₂ is 1.14μm as measured by sedimentation method, d90 is 1.9 .mu.m, d90 / d50 ₂ is 1. The same method as in Example 7 except that 40 parts of kaolin (trade name: Astraplus) 7 and 60 parts of light calcium carbonate (trade name: Brilliant S-15, manufactured by Shiraishi Kogyo Co., Ltd.) with an average particle size of 0.39 μm were used. A coated paper for printing was obtained.

Comparative Example 1
In the preparation of the coating liquid for the coating layer in contact with the base paper of Example 1, a coating liquid was prepared in the same manner except that the blending amount of oxidized starch (trade name: Ace B) was changed to 3 parts, and rod metalling. When coated with a size press coater, roll contamination occurred and a uniform coated surface could not be obtained. For this reason, the coating liquid for the outermost coating layer was not applied.

Comparative Example 2
In the preparation of the coating solution for the coating layer in contact with the base paper of Example 1, 40 parts of delaminated kaolin (trade name: Conzer 2000) as a pigment component and heavy calcium carbonate having an average particle size of 0.8 μm (commodity) Name: 60 parts of Hydrocurve 90, manufactured by Bihoku Flour Chemical Co., Ltd.), 15 parts of oxidized starch (trade name: Ace B) as an adhesive, and styrene-butadiene copolymer latex (trade name: SN-113I) A coated paper for printing was obtained in the same manner as in Example 1 except that 10 parts were used.

Comparative Example 3
In the preparation of the coating layer for a coated liquid in contact with the base paper of Example 1, delaminated kaolin (trade name: contour 2000) instead of an average particle size d50 ₁ as measured by light scattering method 3.7 .mu.m, sedimentation The average particle diameter d50 ₂ measured by the method is 0.95 μm, d50 ₁ / d50 ₂ is 3.9, and the particle size distribution curve by the sedimentation method has a mass distribution of particles of 2 μm or less of 75% and particles of 0.3 μm or less. A coated paper for printing was obtained in the same manner as in Example 1 except that delaminated kaolin (trade name: Capim NP, manufactured by Imeris Co.) having a mass distribution of 16% was used.

Comparative Example 4
In the preparation of the coating layer for a coated liquid in contact with the base paper of Example 1, delaminated kaolin (trade name: contour 2000) instead of an average particle size d50 ₁ is 2.0μm as measured by light scattering method, sedimentation The average particle diameter d50 ₂ measured by the method is 0.28 μm, d50 ₁ / d50 ₂ is 7.1, and the particle size distribution curve by the sedimentation method has a mass distribution of particles of 2% or less of 95% and particles of 0.3 μm or less. A coated paper for printing was obtained in the same manner as in Example 1 except that kaolin (trade name: Milagros J, manufactured by Engelhard) having a mass distribution of 53% was used.

Comparative Example 5
In the preparation of the coating layer for a coated liquid in contact with the base paper of Example 1, delaminated kaolin (trade name: contour 2000) instead of an average particle size d50 ₁ as measured by light scattering method 3.2 .mu.m, sedimentation The average particle diameter d50 ₂ measured by the method is 0.65 μm, d50 ₁ / d50 ₂ is 4.9, and the particle size distribution curve by the sedimentation method has a mass distribution of particles of 2 μm or less of 81% and particles of 0.3 μm or less A coated paper for printing was obtained in the same manner as in Example 1 except that delaminated kaolin having a mass distribution of 26% (trade name: Astra Plate, manufactured by Imeris) was used.

Comparative Example 6
In the preparation of the coating layer for a coated liquid in contact with the base paper of Example 1, delaminated kaolin (trade name: contour 2000) instead of an average particle size d50 ₁ as measured by light scattering method 1.4 [mu] m, sedimentation The average particle size d50 ₂ measured by the method is 0.48 μm, d50 ₁ / d50 ₂ is 2.9, and the particle size distribution curve by the sedimentation method has a mass distribution of particles of 2 μm or less of 97% and particles of 0.3 μm or less A coated paper for printing was obtained in the same manner as in Example 1 except that kaolin (trade name: Paraprint, manufactured by PPSA) having a mass distribution of 29% was used.

Comparative Example 7
In the preparation of the coating layer for a coated liquid in contact with the base paper of Example 1, delaminated kaolin (trade name: contour 2000) instead of an average particle size d50 ₁ as measured by light scattering method 6.8 [mu] m, sedimentation The average particle diameter d50 ₂ measured by the method is 1.06 μm, d50 ₁ / d50 ₂ is 6.4, and the particle size distribution curve by the sedimentation method has a mass distribution of particles of 2 μm or less of 64% and particles of 0.3 μm or less A coated paper for printing was obtained in the same manner as in Example 1 except that delaminated kaolin (trade name: Ultimat, manufactured by Engelhard) having a mass distribution of 22% was used.

Comparative Example 8
Heavy calcium carbonate having an average particle size of 0.8 μm without using delaminated kaolin (trade name: Konzer 2000) as a pigment component in the preparation of a coating solution for a coating layer in contact with the base paper of Comparative Example 2 (Trade name: Hydrocurve 90) A coated paper for printing was obtained in the same manner as in Comparative Example 2 except that 100 parts were used.

  A film transfer system in which the coating layer in contact with the base paper contains 55% by mass or more of a specific delaminated kaolin pigment component and 5 to 40 parts by mass of a starch derivative as an adhesive per 100 parts by mass of the pigment The coated paper for printing, which is formed by coating and forming a coating layer mainly composed of pigment and adhesive on it, has excellent surface smoothness, ink fillability and printing smoothness It is also excellent in printability such as, and can be applied as a lightweight coated paper.

Claims (7)

In a coated paper for printing, in which two or more coating layers mainly composed of pigment and adhesive are provided on at least one side of the base paper, the coating layer in contact with the base paper is applied by a film transfer method, and the coating is in contact with the base paper The layer has, as a pigment, an average particle diameter d50 ₁ measured by a light scattering method in the range of 2.0 to 5.0 μm, and an average particle diameter d50 ₂ measured by a sedimentation method of 0.35 to 0.55 μm. The ratio of the average particle diameter d50 ₁ to the average particle diameter d50 ₂ (d50 ₁ / d50 ₂ ) is 4 or more, and in the particle size distribution curve by the precipitation method, the mass distribution of particles of 2 μm or less Is in the range of 80 to 95%, and the mass distribution of the delaminated kaolin in the pigment includes the delaminated kaolin in which the mass distribution of particles of 0.3 μm or less is in the range of 30 to 45%. A coated paper for printing, wherein the coating layer is 55 to 100% by mass and the coating layer in contact with the base paper contains 5 to 40 parts by mass of a starch derivative as an adhesive per 100 parts by mass of the pigment .   The coating layer in contact with the base paper contains, as an adhesive, 1 to 20 parts by mass of a copolymer latex having a particle diameter of 40 to 150 nm per 100 parts by mass of the pigment. Coated paper for printing. In the coated paper for printing, the outermost coating layer is, as a pigment, an average particle diameter d50 ₂ as measured by sedimentation method is in the range of 0.2～1.6Myuemu, 90 cumulative particle size distribution curve by sedimentation method The ratio of the particle diameter d90 corresponding to mass% and the average particle diameter d50 ₂ (d90 / d50 ₂ ) includes kaolin in the range of 1 to 4.0, and the mass ratio of the kaolin in the pigment is It is 55-100 mass%, The coated paper for printing of Claim 1 or 2 characterized by the above-mentioned. A method for producing a coated paper for printing in which two or more coating layers mainly comprising a pigment and an adhesive are provided on at least one side of a base paper, the method comprising the following steps A and B A manufacturing method of a coated paper for printing characterized.
Average as coated liquid for forming a coating layer in contact with the base paper, the average particle size d50 ₁ as measured by light scattering method is in the range of 2.0～5.0Myuemu, was determined by sedimentation method: Step A The particle diameter d50 ₂ is in the range of 0.35 to 0.55 μm, the ratio of the average particle diameter d50 ₁ to the average particle diameter d50 ₂ (d50 ₁ / d50 ₂ ) is 4 or more, and the precipitation method In the particle size distribution curve according to the above, a delaminated kaolin in which the mass distribution of particles of 2 μm or less is in the range of 80 to 95% and the mass distribution of particles of 0.3 μm or less is in the range of 30 to 45%, A process for preparing a dispersion having a mass ratio of 55 to 100% by mass of the delaminated kaolin in the pigment and 5 to 40 parts by mass of a starch derivative per 100 parts by mass of the pigment as an adhesive. Step and Step B: A step of coating the coating liquid prepared in Step A on at least one side of the base paper by a film transfer method.   The method for producing a coated paper for printing according to claim 4, wherein at least one of a thickener and a water retention agent is added to a coating liquid for forming a coating layer in contact with the base paper. .   The method for producing a coated paper for printing according to claim 5, wherein 0.01 to 1.0 part by mass of at least one thickener or water retention agent is added per 100 parts by mass of the pigment. In the method for producing the coated paper for printing, the coating liquid for forming the outermost coating layer has an average particle diameter d50 ₂ measured by a sedimentation method in the range of 0.2 to 1.6 μm. And a kaolin having a ratio (d90 / d50 ₂ ) of the particle diameter d90 corresponding to 90 cumulative mass% of the particle size distribution curve by the sedimentation method to the average particle diameter d50 _{2 in} the range of 1 to 4.0, and And a step of preparing a dispersion containing an adhesive having a mass ratio of the kaolin in the pigment of 55 to 100% by mass and applying the coating solution by a blade method. The manufacturing method of the coated paper for printing as described in any one of Claim 4 to 6 characterized by these.