JP2011153388A - Coated paper, and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coated paper having low smoothness, high print glossiness, no unevenness on the coated surface and excellent printability. <P>SOLUTION: In the coated paper obtained by providing a base paper with an under coating layer containing a pigment and an adhesive and a top coating layer, the base paper contains &ge;5 mass% of calcium carbonate, the under coating layer contains &ge;75 pts.mass of ground calcium carbonate as the pigment based on 100 pts.mass of the pigment, the top coating layer contains &ge;75 pts.mass of kaolin as a pigment based on 100 pts.mass of the pigment. The top coating layer has a density of 1.0-1.3 g/cm<SP>3</SP>and a basis weight of &le;65 g/m<SP>2</SP>. The coated amount of the under coating layer is 2-8 g/m<SP>2</SP>per side and the coated amount of the top coating layer is 3-10 g/m<SP>2</SP>per side. Preferably the coated paper has a whiteness of &ge;80%, an opacity of &ge;85%, a white paper glossiness of 30-50% and a Bekk smoothness of 400-800 seconds. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

The present invention relates to a coated paper and a method for producing the same. More specifically, the present invention relates to a coated paper having high printing gloss and no printing unevenness, and a method for producing the same.

A so-called coated paper obtained by coating a pigment on a base paper has high whiteness, gloss, and smoothness, and is excellent in printing. Therefore, the frequency of using coated paper in various fields is increasing. Along with the expansion of applications, what is called matte coated paper is used in addition to the glossy paper with high glossiness that has been the mainstream in the past.
Matte coated paper is classified into two types: matte tone with low white paper and low print glossiness, and dull tone with low white paper glossiness, but with a print gloss level similar to that of general coated paper. Separated. Matte coated paper can give the printed material a refined, moist and high-class feeling compared to high glossy paper like ordinary printing paper, so matte coating can be applied to low-grade printing paper. There is a growing demand for paper assortments.

Especially for dull matte coated paper, the glossiness after printing is similar to that of general coated paper, so it can be finished in a contrast-rich print by clearly highlighting the image area. It is used a lot.

In general, as seen in Patent Document 1, a matte coated paper is produced by a high amount of calcium carbonate, which is a coarse-grained pigment, and is commercialized by high-temperature soft calendering. The glossiness of printing does not increase so much.

On the other hand, a coated paper provided with a coating layer mainly composed of delaminated kaolin has been proposed in Patent Document 2, but other pigments to be used in combination have not been specifically examined, and the glossiness of blank paper is low. However, there is a problem that the print glossiness is lowered accordingly.

Further, Patent Document 3 has an application for providing a coating layer containing light calcium carbonate, heavy calcium carbonate, and delaminated kaolin.

In particular, in order to produce lightweight dull matte coated paper, it is necessary to reduce the amount of coating, and calendering with a low nip is performed while suppressing the calcium carbonate content. Unevenness occurs and the texture after printing is impaired.

In order to solve such a problem, a matte coated paper having two coating layers has been filed.
In Patent Document 4, in a double coating method, a base paper having a specific smoothness is used, and a coating composition mainly composed of fine kaolin is provided as an overcoat coating layer, thereby being excellent in printability and printing workability. A method of manufacturing a dull-tone coated paper has been proposed. However, the undercoat coating layer is not particularly limited.

Patent Document 5 proposes that, in a double coating method, a delaminated clay having a large particle diameter is contained in the undercoat coating layer, and kaolin having a small particle diameter is contained in the topcoat coating layer.

Japanese Patent Laid-Open No. 5-117995 JP-A-5-5297 JP-A-11-302998 Japanese Patent Laid-Open No. 7-119085 JP 2005-133278 A

With the above technology, the glossiness is similar to that of normal non-coated printing paper, the printing glossiness is high, and the dull tone coating that can finish the printed matter with high contrast by clearly distinguishing the character part and the image line part. Work paper is available, but improvements such as uneven printing are desired.

SUMMARY OF THE INVENTION An object of the present invention is to provide a coated paper having high printing glossiness, uniform printing surface and excellent printability, and a method for producing the same.

The first invention is
In a coated paper having a base coat layer and a top coat layer containing a pigment and an adhesive on the base paper, the base paper contains 5% by mass or more of calcium carbonate, and the base coat layer is heavy as a pigment. Calcium carbonate is contained in an amount of 75 parts by mass or more per 100 parts by mass of the pigment, the overcoat coating layer contains kaolin in an amount of 75 parts by mass or more per 100 parts by mass of the pigment, and the density is 1.0 to 1.3 g / cm ³ . A coated paper, characterized in that the amount is 65 g / m ² or less. It is.

The second invention is characterized in that, in the first invention, the coating amount of the undercoat coating layer is ^{2 to} 8 g / m ² per side, and the coating amount of the top coating layer is 3 to 10 g / m ² per side. To do.
The coated paper of the third invention is the first invention or the second invention,
A coated paper having a whiteness of 80% or more, an opacity of 85% or more, a white paper gloss of 30 to 50%, and a Beck smoothness of 400 to 800 seconds. It is.

The fourth invention is
In the production method of coated paper, which has a base coat layer containing pigment and adhesive on the base paper and a top coat layer, the base coat is applied by the film transfer method and the top coat is applied by the blade method. By setting the number of adhesive parts per 100 parts by mass of the pigment in the undercoat coating layer to 1 to 3 parts by mass of latex adhesive, 12 to 7 parts by mass of starch adhesive, and 13 to 10 parts by mass of the total adhesive part A method for producing a coated paper, characterized in that the air resistance of the paper after coating and drying of the undercoat coating layer is adjusted to 1000 to 3000 seconds. It is.

According to the present invention, it is possible to obtain a coated paper having a high printing glossiness, no uneven printing surface, and excellent printability.

The present invention is a coated paper in which a base paper is provided with an undercoat coating layer and a topcoat coating layer containing a pigment and an adhesive, and the base paper is made of chemical pulp such as softwood kraft pulp (NKP) or hardwood kraft pulp (LKP). The main raw material. As other pulp, waste paper deinking pulp (DIP) and mechanical pulp can be used. Waste paper deinked pulp is obtained by deinking waste newspaper, magazine waste paper, and the like, and is preferably blended in a high amount from the viewpoint of resource reuse. As the mechanical pulp, thermomechanical pulp (TMP), ground wood pulp (GP), refiner ground wood pulp (RGP), pressured ground wood pulp (PGW), or the like can be used. These mechanical pulps contribute to the improvement of bulk and opacity.
Known fillers such as heavy calcium carbonate, light calcium carbonate, kaolin, clay, talc, hydrated silicic acid, white carbon, titanium oxide, and synthetic resin filler can be used as the filler to be blended into the base paper. Among these, it is preferable to contain 5% by mass or more of calcium carbonate per mass of pulp in order to increase whiteness and opacity.
In addition, if necessary, a sulfuric acid band, a sizing agent, a paper strength enhancer, a yield improver, a dye, an antifoaming agent, a slime control agent and the like may be contained.

The paper making method of the base paper is not particularly limited, and any of base paper made by acid paper making or neutral paper making using a long net machine including a top wire or a circular net machine may be used.
Furthermore, a surface treatment agent containing a water-soluble polymer as a main component may be applied to the base paper before providing a coating layer containing a pigment and an adhesive for the purpose of improving size and rigidity. As the water-soluble polymer, those usually used as surface treating agents such as oxidized starch, hydroxyethyl etherified starch, enzyme-modified starch, polyacrylamide, polyvinyl alcohol, etc. can be used alone or a mixture thereof. . In addition to the water-soluble polymer, a paper strength enhancer for the purpose of improving water resistance and improving the surface strength and an external sizing agent for the purpose of imparting size can be added to the surface treatment agent. The surface treatment agent can be applied by a coating machine such as a two roll size press coater, a gate roll coater, a blade metalling size press coater, a rod metalling size press coater, a film transfer type roll coater such as a shim sizer or a JF sizer. . As for the basic weight of the base paper for coated paper used for this invention, 30-60 g / m < ² > is preferable.

In the present invention, an undercoat coating layer and a topcoat coating layer containing a pigment and an adhesive are sequentially provided on the aforementioned base paper. In the present invention, an undercoat coating layer is previously formed on the base paper, and the penetration of the topcoat coating layer into the base paper layer is suppressed and uniformed, the smoothness of the topcoat coating layer is increased, and the coating layer is made uniform is important.
It is necessary to mix heavy calcium carbonate in the coating layer of the undercoat of the coated paper of the present invention, and the blending amount is 75 parts by mass or more, preferably 90 to 100 parts by mass per 100 parts by mass of the pigment. Part.
The particle diameter of the heavy calcium carbonate is preferably 80% by mass or more with 2 μm under as the particle size distribution. If the particle size is larger than this, the smoothness becomes poor, and it is difficult to ensure good printability. Especially in film transfer coating, coating such as mist generation at the nip portion on the exit side of the applicator roll is difficult. Engineering defects may occur.
Moreover, when the compounding quantity of heavy calcium carbonate is less than 75 mass parts per 100 mass parts of pigments, there exists a tendency for whiteness to become low.

Moreover, 75 parts by mass or more of kaolin per 100 parts by mass of the pigment is blended in the top coat layer.
When the amount of kaolin is less than 75 parts by mass, the print glossiness is lowered.
And it is preferable to mix | blend 10 mass parts or more of delaminated kaolin among 100 mass parts of all kaolins. The delaminated kaolin used preferably has an aspect ratio of 30 to 70. By doing in this way, it can be set as the coated paper with high printing glossiness and a printing nonuniformity. As for the particle size of the other kaolin, it is preferable to use fine kaolin having a particle size distribution with a 2 μm under 90% by mass or more.
When kaolin having a particle size larger than this is used, the print glossiness becomes insufficient.
By doing so, it is possible to obtain a coated paper having high printing glossiness and no printing unevenness.

In the present invention, by adding heavy calcium carbonate to the undercoat coating layer, the whiteness is improved, and by adding fine kaolin having a small particle diameter and delaminated kaolin to the topcoat layer. Since the coated paper with a white paper glossiness of 30 to 50% and a Beck smoothness of 400 to 800 seconds can be obtained by applying no smoothing or weak smoothing, the coating has a low density and a hand feeling. A craft paper can be obtained.
In addition to the above pigments, conventionally used for coated paper, such as light calcium carbonate, talc, titanium dioxide, barium sulfate, calcium sulfate, zinc oxide, silicic acid, silicate, colloidal silica, satin white, etc. One or more inorganic pigments can be mixed and used as necessary.

The adhesive used for the undercoat layer or topcoat layer of the present invention is a styrene / butadiene type, styrene / acrylic type, ethylene / vinyl acetate type, butadiene / methyl, which has been conventionally used for coated paper. Synthetic adhesives such as methacrylate type, vinyl acetate / butyl acrylate type copolymers and polyvinyl alcohol, maleic anhydride copolymer, acrylic acid / methyl methacrylate type copolymer, casein, soy protein, synthetic protein Normal coating of proteins, oxidized starch, positive starch, urea phosphated starch, etherified starch such as hydroxyethyl etherified starch, starch such as dextrin, cellulose derivatives such as carboxyethylcellulose, hydroxyethylcellulose, hydroxymethylcellulose Appropriate one or more paper adhesives -Option to be used.

The adhesive used in the coating layer is not particularly limited, but the number of adhesive parts of the undercoat coating layer is 1 to 3 parts by weight of latex and 12 to 7 parts by weight of starch with respect to 100 parts by weight of pigment, and the total number of adhesive parts is 13 It is preferable to set it as -10 mass parts.
When the number of latex parts is less than 1 part by mass, the surface strength is insufficient. When the amount is more than 3 parts by mass, it is difficult to make the air resistance after the undercoat coating 3000 seconds or less. If the starch is less than 7 parts by mass, the surface strength is insufficient, and if it is more than 12 parts by mass, the total number of adhesive parts increases, making it difficult to reduce the air resistance after undercoating to 3000 seconds or less. When the total number of adhesive parts is less than 10 parts by mass, the surface strength is insufficient. When the total number of parts is more than 13 parts by mass, it is difficult to reduce the air resistance after undercoating to 3000 seconds or less.

In the present invention, the air resistance of the paper after coating and drying of the undercoat coating layer is adjusted to 1000 to 3000 seconds. By adjusting the air resistance, the problem of insufficient printing gloss and uneven printing that occurs when the penetration of the top coating liquid is large, and the moisture evaporation on the surface of the coating layer that occurs when the penetration of the top coating liquid is low. This solves the problem of uneven printing due to binder migration.
If the air permeability resistance is less than 1000 seconds, the top coat layer penetrates into the paper layer, the printing glossiness is insufficient, and the coating liquid is likely to permeate unevenly, resulting in uneven printing. If it exceeds 3000 seconds, since the permeation of the top coating liquid into the paper layer is suppressed, water evaporation from the surface of the coating layer increases, binder migration of the top coating layer occurs, and printing unevenness becomes remarkable. .

The type of the adhesive used for the top coat layer is not particularly limited, but it is preferable to mainly use a latex having a high effect of improving the surface strength even with a small amount. The number of parts by mass of the adhesive of the top coat layer is 5 to 25 parts by mass, preferably about 10 to 20 parts by mass with respect to 100 parts by mass of the pigment.
In addition, the coating layer is blended in a normal coating paper paint, such as a dispersant, a thickener, a water retention agent, an antifoaming agent, a water resistance agent, a colorant, and a printability improver, as necessary. Various auxiliaries are appropriately used.

As a method of applying the paint to the base paper, a film roll type roll coater such as a two roll size press, a gate roll coater, a blade metalling size press coater, a rod metalling size press coater, a shim sizer, a JF sizer, In addition to flooded nip / blade coater, jet fountain / blade coater, short dwell time application type coater, rod metering coater using grooved rod, plain rod, etc. instead of blade, curtain coater, die coater, etc. It can coat with a well-known coater. In the present invention, when a low coating amount is used in the undercoating, it can be applied uniformly by using a film transfer type coater, and the surface property and quality are excellent. The coating amount of the undercoat coating layer is preferably ² to 8 g / m ² per side, more preferably 4 to 8 g / m ² , and the top coating layer is preferably 3 to 10 g / m ² per side, more preferably from 4~8g / ^{m 2.} If the coating amount of the undercoat is small, it is difficult to make the air resistance after the undercoat coating 1000 seconds or more. When the amount of the undercoat coating is large, it becomes difficult to make the air resistance after the undercoat coating 3000 seconds or less. If the amount of the top coat is small, the glossiness of the blank paper and the print gloss are inferior. If the amount of the top coat is large, it is difficult to reduce the weight. In this way, a coated paper having a basis weight of 65 g / m ² or less is obtained.

The binder migration described above refers to a phenomenon in which the adhesive component in the coating liquid is not evenly distributed in the coating layer, and is present at the interface between the base paper and the coating layer or on the surface of the coating layer.
The cause of the occurrence is considered to be due to the movement of moisture (water absorption to the base paper and evaporation) between the time when the coating liquid comes into contact with the surface of the base paper and it dries. In particular, binder migration to the coated paper surface caused by evaporated water causes uneven printing.
Binder migration increases with the presence of starch. This is because starch has a hydroxyl group, and many starches used in coated paper have increased hydrophilicity by introducing a phosphate group or the like, and are easily moved by water.

When SBR latex coexists with starch, it causes binder migration in the form of being pulled by starch. This phenomenon is more likely to occur as the particle size of the latex is smaller.
In the case of a coating method that adjusts the coating amount by scraping the coating liquid, such as blades, air knives, and bar coaters, water absorption to the base paper is also possible during the time it takes for the coating liquid to be scraped off. Therefore, it is advantageous to use a show dwell type blade coater with less time.

Drying conditions are also one of the factors of binder migration, and the coated paper quality is affected by the drying strength and drying means. Other factors affecting the water include the water retention of the coating liquid, the amount and size of the base paper gap, and the wettability of the base paper.
The distribution of the adhesive in the coating layer has a great influence on the quality of the coated paper. Blank paper glossiness, blank paper texture, smoothness, air permeability resistance, fillability, printing surface quality, ink setting properties, printing glossiness, pick strength, blister resistance, etc. are affected. Among them, the printing surface quality is particularly problematic. Other physical properties can be adjusted to some extent by the latex content, etc., but nonuniform printing surface quality due to binder migration is difficult to solve.
When these quality deteriorations are severe, there have been restrictions such as changing the composition of the coating liquid and optimizing the drying conditions.

By the way, when producing coated paper with a small amount of coating, there is a demand for ensuring the water retention of the paint and keeping the paint on the surface of the paper layer to improve printability. Compared with, the number of starch parts with high water retention increases, and the total number of adhesive parts in the undercoat layer increases in order to ensure adhesion. The resistance increased, and binder migration of the overcoat layer became prominent, causing printing unevenness.

In order to solve such a problem, the present invention adopts the following configuration.
That is, in a method for producing a coated paper in which an undercoat coating layer containing a pigment and an adhesive and an overcoat coating layer are provided on a base paper, the undercoat is applied by a film transfer method, and the topcoat is applied by a blade method. 1 to 3 parts by weight of the latex-based adhesive and 12 to 7 parts by weight of the starch-based adhesive with respect to 100 parts by weight of the pigment in the undercoat coating layer, and the total number of parts of the adhesive is 13 to 10 parts by weight. As a result, the air resistance of the paper after coating and drying of the undercoat coating layer is adjusted to 1000 to 3000 seconds.
In the present invention, the binder migration of the topcoat coating layer is reduced by reducing the number of adhesive parts and the coating amount of the undercoat coating layer, and by lowering the air resistance of the paper after drying and coating of the undercoat coating layer. Is preventing.
By doing in this way, the coated paper without a printing nonuniformity is obtained.

As a method for drying the coating layer, for example, various methods such as a steam heating cylinder, a hot air air dryer, a gas heater dryer, an electric heater dryer, an infrared heater dryer, and a high frequency heater dryer are used alone or in combination.
The coated paper coated and dried as described above is subjected to a smoothing treatment with a chilled calendar, a super calender, a high-temperature soft nip calender, or the like, whereby the density of the coated paper is 1.0 to 1.3 g / cm ³ , Preferably, it is adjusted to 1.0 to 1.2 g / cm ³ , but the calendar process may not be performed if the target blank paper glossiness is obtained.

As described above, whiteness of 80% or more, opacity of 85% or more, blank paper glossiness of 30 to 50%, Beck smoothness of 400 to 800 seconds, low density, hand feeling, and printing glossiness. A coated paper that is high and has no uneven printing can be obtained.

The present invention will be specifically described below with reference to examples. In addition, the mass%, the mass part, and the coating amount are represented by solid content or active ingredients unless otherwise specified.

Example 1
(Base paper)
Yield improver (100% by weight of pulp raw material mixed with 70% by mass of hardwood bleached kraft pulp (Canadian standard freeness 240ml) and 30% by mass of softwood bleached kraft pulp (Canadian standard freeness 550ml)) Product name DR8500 made by Hymo Co., Ltd.) 0.060 parts by mass, sulfate band 0.9 parts by mass, calcium carbonate (product name TP-121-6S made by Okutama Kogyo Co., Ltd.) 5 mass% as paper ash The base paper was made with an on-top former type paper machine.
(Undercoating)
Next, using a rod metering size press, an undercoat paint containing a pigment and an adhesive was applied on both sides as follows.
Hereinafter, parts by mass of chemicals other than pigments are expressed as parts by mass with respect to 100 parts by mass of pigment.
(Coating for undercoating)
Heavy calcium carbonate (product name Hydrocurve 90HS manufactured by Bihoku Powder Chemical Co., Ltd., particle size distribution: 2 μm under 90% by mass) 100 parts by mass SBR latex (product name SMARTEX PA8008 manufactured by Nippon A & L Co., Ltd.) 2 parts by mass urea phosphate ester Starch 16 (product name: Star Coat 16 manufactured by Nippon Shokuhin Kako Co., Ltd.) 8 parts by mass Dispersant (product name: Aron T50 manufactured by Toagosei Co., Ltd.) 0.2 parts by mass fluorescent dye (product name: Kaya Hall STCL manufactured by Nippon Kayaku Co., Ltd.) 1 .5 parts by mass coating amount 5 g / m ² per side
(Top coat coating)
Next, using a short dwell type blade coater, a top coat coating material containing a pigment and an adhesive was applied on both sides as follows.
(Coating for top coating)
Fine kaolin (product name: Kaofine Shiraishi Calcium Co., Ltd., particle size distribution: 2 μm under 95% by mass or more) 70 parts by weight delaminated kaolin (product name Contour 1500, manufactured by Imerizu Minerals Japan, Inc., aspect ratio 59) 30 14 parts by weight SBR latex (Smartex PA8008) 14 parts by weight urea phosphate esterified starch (Starcoat 16) 2 parts by weight dispersant (Aron T50) 0.2 parts by weight fluorescent dye (Kayahole STCL) 1.5 parts by weight 8g / m ² per
The coated paper was dried and subjected to soft calender 2 nip treatment (nip pressure 60 kN / m temperature 180 ° C., nip pressure 60 kN / m temperature 150 ° C.) to obtain a coated paper having a basis weight of 59.5 g / m ² .

(Example 2)
A coated paper was obtained in the same manner as in Example 1 except that the undercoat paint and the topcoat paint were changed as follows.
(Coating for undercoating)
Heavy calcium carbonate (Hydrocurve 90HS) 90 parts by weight Kaolin (product name: KCS, Imeris Minerals Japan, Inc.) 10 parts by weight SBR latex (Smartex PA8008) 2 parts by weight urea phosphated starch (Starcoat 16) 8 Part by mass Dispersant (Aron T50) 0.2 parts by mass Fluorescent dye (Kaya Hall STCL) 1.5 parts by mass Coating amount 5 g / m ² per side
(Coating for top coating)
Heavy calcium carbonate (Hydrocurve 90HS) 10 parts by weight Fine kaolin (Kaofine) 70 parts by weight Delaminated kaolin (Contour 1500) 20 parts by weight SBR latex (Smartex PA8008) 14 parts by weight Urea phosphate esterified starch (star Coat 16) 2 parts by mass dispersant (Aron T50) 0.2 parts by mass fluorescent dye (Kayahole STCL) 1.5 parts by mass Coating amount 8 g / m ² per side

(Example 3)
A coated paper was obtained in the same manner as in Example 1 except that the undercoat paint and the topcoat paint were changed as follows.
(Coating for undercoating)
Heavy calcium carbonate (Hydrocurve 90HS) 75 parts by weight Kaolin (KCS) 25 parts by weight SBR latex (Smartertex PA8008) 2 parts by weight Urea phosphate esterified starch (Starcoat 16) 8 parts by weight Dispersant (Aron T50) 0.2 Mass part fluorescent dye (Kaya Hall STCL) 1.5 parts by mass Coating amount 5 g / m ² per side
(Coating for top coating)
Heavy calcium carbonate (Hydrocurve 90HS) 25 parts by weight Fine kaolin (Kaofine) 65 parts by weight Delaminated kaolin (Contour 1500) 10 parts by weight SBR latex (Smartex PA8008) 14 parts by weight Urea phosphate esterified starch (star Coat 16) 2 parts by mass dispersant (Aron T50) 0.2 parts by mass fluorescent dye (Kayahole STCL) 1.5 parts by mass Coating amount 8 g / m ² per side

Example 4
A coated paper was obtained in the same manner as in Example 1 except that the undercoat paint was changed as follows.
(Coating for undercoating)
Heavy calcium carbonate (Hydrocurve 90HS) 100 parts by weight SBR latex (Smartex PA8008) 3 parts by weight Urea phosphate esterified starch (Starcoat 16) 10 parts by weight Dispersant (Aron T50) 0.2 parts by weight Fluorescent dye (Kayahole STCL) ) 1.5 parts by mass coating amount 5 g / m ² per side

(Example 5)
A coated paper was obtained in the same manner as in Example 1 except that the undercoat paint and the topcoat paint were changed as follows.
(Coating for undercoating)
Heavy calcium carbonate (Hydrocurve 90HS) 100 parts by weight SBR latex (Smartex PA8008) 2 parts by weight Urea phosphate esterified starch (Starcoat 16) 8 parts by weight Dispersant (Aron T50) 0.2 parts by weight Fluorescent dye (Kayahole STCL) ) 1.5 parts by mass coating amount 8 g / m ² per side
(Coating for top coating)
Fine kaolin (Kaofine) 70 parts by weight Delaminated kaolin (Contour 1500) 30 parts by weight SBR latex (Smartertex PA8008) 15 parts by weight Urea phosphate esterified starch (Starcoat 16) 1 part by weight Dispersant (Aron T50) 0 .2 parts by weight fluorescent dye (Kaya Hall STCL) 1.5 parts by weight Coating amount 7 g / m ² per side

(Example 6)
A coated paper was obtained in the same manner as in Example 1 except that the undercoat paint and the topcoat paint were changed as follows.
(Coating for undercoating)
Heavy calcium carbonate (Hydrocurve 90HS) 100 parts by weight SBR latex (Smartex PA8008) 1 part by weight Urea phosphate esterified starch (Starcoat 16) 12 parts by weight Dispersant (Aron T50) 0.2 parts by weight Fluorescent dye (Kayahole STCL) ) 1.5 parts by mass coating amount 3 g / m ² per side
(Coating for top coating)
Fine kaolin (Kaofine) 70 parts by weight Delaminated kaolin (Contour 1500) 30 parts by weight SBR latex (Smartex PA8008) 14 parts by weight Urea phosphate esterified starch (Starcoat 16) 2 parts by weight Dispersant (Aron T50) 0 .2 parts by weight fluorescent dye (Kaya Hall STCL) 1.5 parts by weight Coating amount 10 g / m ² per side

(Comparative Example 1)
A coated paper was obtained in the same manner as in Example 1 except that the undercoat paint and the topcoat paint were changed as follows.
(Coating for undercoating)
Heavy calcium carbonate (Hydrocurve 90HS) 60 parts by weight Kaolin (KCS) 40 parts by weight SBR latex (Smartex PA8008) 2 parts by weight Urea phosphate esterified starch (Starcoat 16) 8 parts by weight Dispersant (Aron T50) 0.2 Mass part fluorescent dye (Kaya Hall STCL) 1.5 parts by mass Coating amount 5 g / m ² per side
(Coating for top coating)
Fine kaolin (Kaofine) 100 parts by weight SBR latex (Smartex PA8008) 14 parts by weight Urea phosphate esterified starch (Starcoat 16) 2 parts by weight Dispersant (Aron T50) 0.2 parts by weight Fluorescent dye (Kayahole STCL) 5 parts by mass coating amount 8 g / m ² per side

(Comparative Example 2)
A coated paper was obtained in the same manner as in Example 1 except that the undercoat paint was changed as follows.
(Coating for undercoating)
Heavy calcium carbonate (Hydrocurve 90HS) 60 parts by weight Kaolin (KCS) 40 parts by weight SBR latex (Smartex PA8008) 4 parts by weight Urea phosphate esterified starch (Starcoat 16) 8 parts by weight Dispersant (Aron T50) 0.2 Mass part fluorescent dye (Kaya Hall STCL) 1.5 parts by mass Coating amount 5 g / m ² per side

(Comparative Example 3)
A coated paper was obtained in the same manner as in Example 1 except that the undercoat paint and the topcoat paint were changed as follows.
(Coating for undercoating)
Heavy calcium carbonate (Hydrocurve 90HS) 75 parts by weight Kaolin (KCS) 25 parts by weight SBR latex (Smartertex PA8008) 2 parts by weight Urea phosphate esterified starch (Starcoat 16) 8 parts by weight Dispersant (Aron T50) 0.2 Mass part fluorescent dye (Kaya Hall STCL) 1.5 parts by mass Coating amount 5 g / m ² per side
(Coating for top coating)
Heavy calcium carbonate (Hydrocurve 90HS) 35 parts by weight Fine kaolin (Kaofine) 50 parts by weight Delaminated kaolin (Contour 1500) 15 parts by weight SBR latex (Smartex PA8008) 14 parts by weight Urea phosphate esterified starch (star Coat 16) 2 parts by mass dispersant (Aron T50) 0.2 parts by mass fluorescent dye (Kayahole STCL) 1.5 parts by mass Coating amount 8 g / m ² per side

(Comparative Example 4)
A coated paper was obtained in the same manner as in Example 1 except that the undercoat paint and the topcoat paint were changed as follows.
(Coating for undercoating)
Heavy calcium carbonate (Hydrocurve 90HS) 75 parts by weight Kaolin (KCS) 25 parts by weight SBR latex (Smartertex PA8008) 2 parts by weight Urea phosphate esterified starch (Starcoat 16) 8 parts by weight Dispersant (Aron T50) 0.2 Mass part fluorescent dye (Kaya Hall STCL) 1.5 parts by mass Coating amount 5 g / m ² per side
(Coating for top coating)
Heavy calcium carbonate (Hydrocurve 90HS) 35 parts by weight Fine kaolin (Kaofine) 65 parts by weight SBR latex (Smartertex PA8008) 14 parts by weight Urea phosphate esterified starch (Starcoat 16) 2 parts by weight Dispersant (Aron T50) 0 .2 parts by weight fluorescent dye (Kaya Hall STCL) 1.5 parts by weight Coating amount 8 g / m ² per side

(Comparative Example 5)
A coated paper was obtained in the same manner as in Example 1 except that the undercoat paint and the topcoat paint were changed as follows.
(Coating for undercoating)
Heavy calcium carbonate (Hydrocurve 90HS) 60 parts by weight Kaolin (KCS) 40 parts by weight SBR latex (Smartex PA8008) 4 parts by weight Urea phosphate esterified starch (Starcoat 16) 6 parts by weight Dispersant (Aron T50) 0.2 Mass part fluorescent dye (Kaya Hall STCL) 1.5 parts by mass Coating amount 9 g / m ² per side
(Coating for top coating)
Fine Kaolin (Kaofine) 70 parts by weight Delaminated Kaolin (Contour 1500) 30 parts by weight SBR Latex (Smartex PA8008) 14 parts by weight Urea phosphate esterified starch (Starcoat 16) 2 parts by weight dispersant (Aron T50) 0.2 parts by mass fluorescent dye (Kaya Hall STCL) 1.5 parts by mass coating amount 4 g / m ² per side

(Comparative Example 6)
A coated paper was obtained in the same manner as in Example 1 except that the undercoat paint and the topcoat paint were changed as follows.
(Coating for undercoating)
Heavy calcium carbonate (Hydrocurve 90HS) 75 parts by weight Kaolin (KCS) 25 parts by weight Urea phosphate esterified starch (Starcoat 16) 14 parts by weight Dispersant (Aron T50) 0.2 parts by weight Fluorescent dye (Kayahole STCL) 5 parts by mass coating amount 5 g / m ² per side
(Coating for top coating)
Heavy calcium carbonate (Hydrocurve 90HS) 35 parts by weight Fine kaolin (Kaofine) 40 parts by weight Delaminated kaolin (Contour 1500) 25 parts by weight SBR latex (Smartex PA8008) 14 parts by weight Urea phosphate esterified starch (star Coat 16) 2 parts by mass dispersant (manufactured by Aron T50) 0.2 parts by mass fluorescent dye (Kaya Hall STCL) 1.5 parts by mass coating amount 8 g / m ² per side

(Comparative Example 7)
A coated paper was obtained in the same manner as in Example 1 except that the undercoat paint and the topcoat paint were changed as follows.
(Coating for undercoating)
Heavy calcium carbonate (Hydrocurve 90HS) 75 parts by weight Kaolin (KCS) 25 parts by weight Urea phosphate esterified starch (Starcoat 16) 20 parts by weight Dispersant (Aron T50) 0.2 parts by weight Fluorescent dye (Kayahole STCL) 5 mass parts coating amount 1.8 g / m ² per side
(Coating for top coating)
Heavy calcium carbonate (Hydrocurve 90HS) 35 parts by weight Fine kaolin (Kaofine) 40 parts by weight Delaminated kaolin (Contour 1500) 25 parts by weight SBR latex (Smartex PA8008) 14 parts by weight Urea phosphate esterified starch (star Coat 16) 2 parts by mass dispersant (manufactured by Aron T50) 0.2 parts by mass fluorescent dye (Kaya Hall STCL) 1.5 parts by mass coating amount 8 g / m ² per side

Tables 1 to 3 show the production conditions of Examples 1 to 6 and Comparative Examples 1 to 7 and the evaluation results of the obtained coated paper. In addition, the number of parts of the pigment is represented by the number of parts when the total pigment of each coating layer is 100 parts by mass, and the number of parts of the adhesive is represented by the number of parts for 100 parts by mass of the pigment of each coating layer.

The evaluation method of the coated paper was as follows.
(Basis weight) JISP 8124: 1998 paper and board-basis weight measurement method (density) JISP 8118: 1998 paper and board-thickness and density test method (air permeability resistance) JISP 8117: 1998 paper and board-air permeability test method -Gurley tester method (whiteness) JISP8148: 2001 paper, paperboard and pulp-ISO whiteness (diffuse blue light reflectance) measurement method (opacity) JISP8149: 2000 paper and paperboard-Opacity test method (back of paper) Bias)-Diffuse irradiation method (white paper glossiness) JISP8142: 2005 paper and paperboard-75 degree specular gloss measurement method (smoothness) JISP8119: 1998 paper and paperboard-Smoothness test method with Beck smoothness tester (printing gloss) Degree evaluation) Using an RI printing tester, offset printing ink (trade name: Web World MP Ai DI Co., Ltd.) was used at a printing speed of 32.5 Hz, dried for 30 seconds with a dryer set at 130 ° C., and measured according to JISP8142: 2005 paper and paperboard-75 degree specular gloss measurement method. The glossiness was measured. Evaluation was made in four stages according to the following evaluation criteria.
◎ 72 or more ◯ 70 or more and less than 72 △ 68 or more and less than 70 × 68 (unevenness of printing) The printed surface of the coated paper produced by the RI printing tester was subjected to relative evaluation in the following four stages by visual evaluation.
◎ Excellent ○ Good △ Slightly bad × Poor

The coated papers shown in Examples 1 to 6 of the present invention had high print glossiness and good print unevenness evaluation.
On the other hand, in Comparative Example 1, the amount of heavy calcium carbonate contained in the undercoat coating layer is as small as 60 parts by mass,
The whiteness is slightly low. Further, since the top coat layer does not contain delaminated kaolin, the glossiness of the white paper is low, and the print glossiness evaluation is poor.

In Comparative Example 2, the amount of heavy calcium carbonate contained in the undercoat coating layer is as small as 60 parts by mass,
The whiteness is slightly low. Moreover, since there are many latex parts, the air permeation resistance after undercoating becomes high, and the evaluation of printing unevenness is deteriorated.

In Comparative Example 3, the kaolin contained in the top coat layer is as small as 65 parts by mass, and the glossiness of the white paper is low.

In Comparative Example 4, the kaolin contained in the topcoat coating layer is as small as 65 parts by mass, and since no delaminated kaolin is contained, the glossiness of the blank paper is low and the evaluation of the printing glossiness is poor.

In Comparative Example 5, compared with Comparative Example 2, since the amount of the undercoat applied is large, the air resistance after the undercoat is increased, and the evaluation of the printing unevenness is deteriorated. In addition, since the amount of overcoating is small, the glossiness of white paper is low, and the evaluation of printing glossiness is poor.

Compared with Comparative Example 3, Comparative Example 6 has a larger number of starch parts by mass in the undercoat coating layer, so that the air resistance after undercoating is increased and the evaluation of printing unevenness is worsened.

In Comparative Example 7, compared with Comparative Example 3, since the coating amount of the undercoat coating layer is small, the air resistance after the undercoat becomes too small, and the evaluation of the printing unevenness is poor.

The coated paper of the present invention can be used as printing paper for publishing such as commercial printing such as leaflets and brochures, and books, magazines, comics, and the like.

Claims (4)

In a coated paper having a base coat layer and a top coat layer containing a pigment and an adhesive on the base paper, the base paper contains 5% by mass or more of calcium carbonate, and the base coat layer is heavy as a pigment. Calcium carbonate is contained in an amount of 75 parts by mass or more per 100 parts by mass of the pigment, the overcoat coating layer contains kaolin in an amount of 75 parts by mass or more per 100 parts by mass of the pigment, and the density is 1.0 to 1.3 g / cm ³ . A coated paper, characterized in that the amount is 65 g / m ² or less. The coating amount according to claim 1, wherein the coating amount of the undercoat coating layer is ^{2 to} 8 g / m ² per side, and the coating amount of the top coat layer is 3 to 10 g / m ² per side. paper. The coated paper according to claim 1, wherein the coated paper has a whiteness of 80% or more, an opacity of 85% or more, a blank paper glossiness of 30 to 50%, and a Beck smoothness of 400 to 800 seconds. In the production method of coated paper, which has a base coat layer containing pigment and adhesive on the base paper and a top coat layer, the base coat is applied by the film transfer method and the top coat is applied by the blade method. By setting the number of adhesive parts per 100 parts by mass of the pigment in the undercoat coating layer to 1 to 3 parts by mass of latex adhesive, 12 to 7 parts by mass of starch adhesive, and 13 to 10 parts by mass of the total adhesive part A method for producing a coated paper, characterized in that the air resistance of the paper after coating and drying of the undercoat coating layer is adjusted to 1000 to 3000 seconds.