JP2003155693A - Coated paper for gravure printing and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide coated paper which is used for gravure printing, hardly causes missing dots, when subjected to a gravure printing treatment, has excellent coating suitability and super calender roll staining resistance, when produced, and has high gloss, high whiteness and excellent gravure printing suitability, and to provide a method for producing the coated paper. SOLUTION: This coated paper for gravure printing, obtained by coating both the sides or one side of base paper consisting mainly of wood pulp with a coating liquid containing a pigment and an adhesive as main components is characterized in that the pigment is precipitated calcium carbonate or hexagonal plate magnesium carbonate. And the method for producing the coated paper.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a coated paper for gravure printing and a method for producing the same, and more specifically, it has less occurrence of missing dots in gravure printing, coating suitability during production and a super calendar roll. The present invention relates to a coated paper for gravure printing, which has excellent stain resistance, high gloss and high whiteness, and is excellent in gravure printing suitability, and a method for producing the same.

[0002]

2. Description of the Related Art Gravure printing has been widely used in recent years because it has excellent gradation reproducibility and enables mass printing.

However, since the gravure printing is a method in which the ink is transferred directly from the minute concave cells of the metal roll to the paper surface, the ink filled in the cells does not completely transfer or drops and is actually formed. White spots in printed parts or printed dots, so-called "missing dots", tend to occur, which is a major defect that impairs gravure printing suitability, that is, the aesthetic appearance of the printed matter.

Since the gravure printing is applied for high-grade printing, the printing effect is extremely poor and the occurrence of missing dots is a fatal defect. In particular, the physical properties of the coated paper for gravure printing will significantly affect the occurrence of missing dots. For this reason, many studies have been made from both sides of the base paper and the coating layer in order to make the physical properties of the coated paper for gravure printing appropriate.

Conventionally, it has been considered that the surface smoothness and cushioning property of coated paper are important factors for preventing the occurrence of missing dots in gravure printing. Although the improvement can be expected, a sufficient effect is not confirmed, and the improvement of the cushioning property is hardly expected.

That is, the coated paper is provided with both surface smoothness and cushioning properties, and when the coated paper is pressed by the plate material at the time of printing, the surface of the plate material and the surface of the coated paper adhere to each other. It is necessary to have a method for improving the surface property and improving it by effectively transferring the ink. For the purpose of surface smoothness of the coated paper for printing, cushioning property for increasing the surface smoothness under pressure, etc. Conventionally, investigations have been made on base paper, improvement of raw materials and binders in coating compositions, super calender conditions, and the like.

As a method for improving the surface smoothness,
For example, Japanese Patent Laid-Open No. 4-370293 discloses a method in which a base paper is provided with a coating layer and then heated steam is applied thereto to perform a soft calendar treatment. A method of super calendering after treatment has been proposed, but strengthening calendering in this way naturally improves the surface smoothness remarkably, but on the contrary, causes a decrease in rigidity and also impairs cushioning properties. Be done.

Further, in order to obtain a high cushioning property under pressure, as a study of the base paper, for example, Japanese Patent Publication No. 63-2
The 7480 gazette devises a method of using high-yield pulp, ground pulp and mechanical pulp, and blending of base paper such as increasing the ratio of pigment to be incorporated.

On the other hand, studies on pigments for coating compositions include, for example, JP-A-7-53609 and JP-A-10-23.
7795 and JP 2000-212892A have been devised to enhance the cushioning property by using bulky kaolin, delaminated clay, cohesive spindle-shaped light calcium carbonate, and talc.

In particular, many contrivances have been made so far with respect to latex as an adhesive agent.
Japanese Patent Laid-Open No. 201599 and Japanese Patent Application Laid-Open No. 2-139500 disclose a method of applying a specific copolymer substance with respect to an adhesive agent for a coating layer. Both of these are copolymer substances obtained by polymerizing by increasing the use ratio of the aliphatic conjugated diene-based monomer, and the glass transition point thereof is lowered to a negative temperature range.

Similarly, JP-A-60-224895 proposes a method of imparting cushioning properties to a coating layer by using a latex having a glass transition point of a polymer in a negative temperature range. There is.

However, basically, there is a contradictory relationship between the improvement of gravure printing suitability and the prevention of stains on the super calender rolls. Thus, simply using latex having a glass transition point in the negative temperature range is certainly Although it is possible to improve the missing dots by improving the cushioning properties of the coating layer, the strength of the coating layer is significantly weakened accordingly, so the coating layer surface peels off on the super calender roll side, and the surface of the super calender roll becomes dirty. Alternatively, it causes deposits, which inevitably causes the production equipment to be periodically stopped for removal work, resulting in a drawback that production efficiency is significantly impaired.

Therefore, in JP-A-10-325099, in order to improve the missing dots of the coated paper for gravure printing, and further to prevent stains on the super calender roll, the glass transition point of the latex is improved and the latex A method for improving the average particle size has also been proposed.

However, in the present invention, for the purpose of improving the missing dots of the coated paper for gravure printing, the bulkiness of kaolin or delaminated clay was used, so that the whiteness was lowered and the coating was carried out with a blade coater. In this case, problems such as streaks, which are streaky defects on the coated surface, often occur during operation. On the other hand, when cohesive light calcium carbonate is used, the whiteness is high but the micro smoothness decreases,
Since it is a matte gravure coated paper, it is difficult to obtain a high gloss gravure coated paper. In addition, light calcium carbonate has a high aggregating property of the pigment, so that the viscosity increases with time, which may impair the quality and operability.
In order to produce coated paper for gravure printing, which has excellent operability, high whiteness, and high gloss, and is excellent in gravure printing suitability,
It is necessary to consider the pigment used and the manufacturing method.

[0015]

The object of the present invention is for gravure printing, which has high gloss and high white color, has less missing dots in gravure printing, and is excellent in coating suitability during production and super calendar roll stain resistance. It is to provide a coated paper and a manufacturing method thereof.

[0016]

As a result of intensive studies to solve the above problems, the present inventor has invented the coated paper for gravure printing of the present invention and a method for producing the same.

That is, the gravure printing coated paper of the first invention is a gravure printing obtained by applying a coating liquid containing a pigment and an adhesive as a main component on both sides or one side of a base paper mainly composed of wood pulp. The coated paper for use is characterized in that the pigments are light calcium carbonate and hexagonal plate-shaped magnesium carbonate.

Further, the coated paper for gravure printing of the second invention is a gravure printing obtained by applying a coating liquid containing a pigment and an adhesive as a main component on both sides or one side of a base paper mainly composed of wood pulp. In the coated paper for use in the application, the pigment comprises light calcium carbonate, hexagonal plate-shaped magnesium carbonate, and an average particle size of 0.
It is a hollow organic pigment having a diameter of 5 μm or more.

In the above invention, the light calcium carbonate is preferably spindle-shaped or columnar, or both.

In the above invention, the adhesive preferably has a glass transition temperature of −30 ° C. or less and an average particle diameter of 150 nm or less.

In the above invention, the content ratio of the light calcium carbonate and the hexagonal plate-shaped magnesium carbonate is 1: 1 to
It is preferably 1: 0.05.

Further, in the method for producing a coated paper for gravure printing in the above invention, a coating solution containing light calcium carbonate and hexagonal plate-shaped magnesium carbonate is coated on a base paper, dried, and then smoothed. It is characterized by being manufactured.

In the manufacturing method of the above-mentioned invention, it is preferable that the coating liquid is a co-dispersion of light calcium carbonate and hexagonal plate-shaped magnesium carbonate, and then pulverization treatment is carried out to an average particle diameter of 1.5 μm or less.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION The coated paper for gravure printing and the method for producing the same of the present invention will be described in detail below.

In the coated paper for gravure printing of the first aspect of the present invention, light calcium carbonate and hexagonal plate-shaped magnesium carbonate are contained as pigments, and a latex having a glass transition point and an average particle diameter within a specific range is used to obtain a missing dot. And the ability to prevent adhesion to the surface of the super calender roll by improving coating strength.

In order to improve the missing dots, it is necessary to enhance the surface smoothness and cushioning properties of the coated paper for gravure printing, and the surface smoothness and cushioning properties of the coating layer that contacts the plate are required. Conventional coated paper for gravure printing uses bulky kaolin or delaminated clay in which pigment particles are in the form of agglomerates. Has adhered to.

The hexagonal plate-shaped magnesium carbonate contained in the coated paper for gravure printing of the present invention has the same primary particle shape as kaolin, but the aggregation form of pigment particles is different,
Kaolin has a laminated structure, but hexagonal plate-shaped magnesium carbonate has a card house structure in which the vertices are joint points, so that the coating layer has excellent cushioning properties.

Further, in the coated paper for gravure printing of the second invention, in addition to hexagonal plate-shaped magnesium carbonate, an average particle diameter of 0.
It is a hollow organic pigment containing a hollow organic pigment of 5 μm or more, preferably having an average particle diameter of 0.8 μm or more, and synergistic between the card house structure of hexagonal magnesium carbonate and the cushioning property of the hollow organic pigment itself. Due to the effect, the cushioning property of the coating layer is further improved.

Examples of the hollow organic pigment used in the present invention include various types of polymerization or copolymers such as polystyrene type and styrene-butadiene type. Specifically, trade name HP-91 (R & H), trade name HP -433J (R &
H), trade name AE-850 (JSR), etc. can be illustrated.

The latex as an adhesive used in the present invention has a glass transition point of -30 ° C or lower, preferably -30 to -40 ° C. When the glass transition point is higher than this temperature range, suitable cushioning properties cannot be obtained, and the occurrence of missing dots becomes remarkable.

The light calcium carbonate, which is a pigment used in the present invention, is superior in adhesiveness to a latex binder as compared with kaolin, so that a high coating layer strength can be obtained and it is excellent in preventing stains on a super calender roll. In order to obtain a cushioning property suitable for the coating layer, it is preferable that one or both of a spindle shape and a columnar shape that do not form a close-packed structure.

The content ratio of light calcium carbonate, which is a pigment used in the present invention, and hexagonal tabular magnesium carbonate is 0.
It is from 05: 1 to 1: 0.05, preferably from 1: 1 to 1: 0.05, and more preferably from 1: 0.5 to 1: 0.05 from the viewpoint of economy.

The pigment dispersion liquid in which the pigment used in the present invention is dispersed in water is dispersed by a Corless disperser or the like and then wet-milled by a sand grinder or the like so that the average particle diameter becomes equal to that of primary particles. The coating area of the pigment and the latex increases, and high coating strength can be obtained. Therefore, it is excellent in preventing stains on the super calendar roll.

The pigment dispersion liquid obtained by co-dispersing light calcium carbonate and hexagonal plate-shaped magnesium carbonate, which are the pigments used in the present invention, in water is similarly dispersed by a Corres disperser, and then average particles are obtained by a sand grinder or the like. The diameter is 1.
It is pulverized so as to have a particle size of 5 μm or less, preferably 0.5 to 1.2 μm.

A pigment dispersion containing only light calcium carbonate is
Since sedimentation occurs due to re-aggregation of the pigment, it is inferior in stability, and when a coating solution is prepared by adding latex or the like, and the pigment is aggregated on the blade tip when coated with a commonly used blade coater. The streaks, which are streak-like defects, occur remarkably on the coated surface because they remain. However, in the pigment dispersion liquid in which light calcium carbonate and hexagonal plate-shaped magnesium carbonate are co-dispersed in water, hexagonal plate-shaped magnesium carbonate having smaller primary particles than light calcium carbonate inhibits re-aggregation of light calcium carbonate. Since a pigment dispersion having excellent stability is obtained, the occurrence of streak defects during operation is suppressed.

The base paper used in the present invention is not particularly limited, and chemical pulp such as LBKP and NBKP, GP, PGW, RMP, TMP, CTMP, CM.
Including mechanical pulp containing P, CGP, etc., waste paper pulp such as DIP, various fillers such as light calcium carbonate, heavy calcium carbonate, talc, clay, kaolin, etc., sizing agents, fixing agents, yield improving agents, cationizing agents, It contains various additives such as paper-strengthening agent, and is paper-made acidic, neutral or alkaline.

The beaten pulp slurry is made by a paper machine such as a Fourdrinier paper machine, a twin wire paper machine, or a round net paper machine. Various additives such as the dispersion aid, the dry paper strengthening agent, the wet paper strengthening agent, the filler, the sizing agent, and the fixing agent can all be added as necessary. Further, if necessary, a pH adjusting agent, a dye, a colored pigment, an optical brightening agent and the like can be added.

The pigment used in the present invention is not limited to light calcium carbonate and hexagonal tabular magnesium carbonate, or in addition to these and hollow organic pigments, other pigments may be added in a small amount. , Kaolin clay, delaminated clay, calcined clay, ground calcium carbonate, aluminum hydroxide, talc, titanium dioxide, etc., but in order to obtain a coated paper for high-gravity gravure printing, High pigments such as ground calcium carbonate, aluminum hydroxide and titanium dioxide are preferred.

The latex used in the present invention includes:
Conjugated diene-based copolymer latex such as styrene / butadiene copolymer, acrylic-based polymer latex such as polymer or copolymer of acrylic acid ester and / or methacrylic acid ester, styrene / vinyl acetate-based copolymer, etc. It is preferable to use a vinyl-based polymer latex or a copolymer latex such as an alkali-sensitive or alkali-insensitive polymer latex obtained by modifying these various polymer latexes with a functional group-containing monomer such as a carboxyl group. it can. In particular, pigment binding strength, workability,
Considering cost and the like, a conjugated diene-based copolymer latex such as a styrene / butadiene copolymer is preferably used.

As other adhesives, oxidized starch,
Etherified starch, esterified starch, enzyme-modified starch and cold water-soluble starch obtained by flash-drying them, casein, natural binders such as soybean protein, and the like can be used in combination. A water-retaining agent such as thickened latex, carboxymethyl cellulose, methyl cellulose, sodium alginate or the like may be appropriately blended.

Further, other commonly used auxiliaries such as dispersants, thickeners, defoamers, lubricants, dyes, optical brighteners and pH adjusters may be appropriately used.

In the method for producing the pigment dispersion of the pigment used in the present invention, initial dispersion is carried out with a disperser, followed by wet grinding with a sand grinder, but the disperser used for the initial dispersion is not particularly limited. A known disperser having a high shearing force, such as a Choles disperser, a stirring disperser, and a homogenizer, can be used.

Further, in the method for producing the pigment dispersion liquid of the pigment used in the present invention, the sand glider used for the wet pulverization is not particularly limited, and for example, a known sand grinder such as a sand mill, an attritor, a dyno mill or a pin mill is used. be able to.

Wet grinding has an average particle size of 0.5 mm to 4 mm.
Beads such as mineral microsand, glass microparticles, hard ceramic microparticles, and metal microparticles in the range of mm are filled in the container in an apparent volume of 30 to 90% by volume, and then, via a stirring blade of an arbitrary shape, It is preferable to continuously pour the pigment slurry into the container with a pump while allowing the beads to be mechanically stirred, and to pass the pigment slurry once or several times.

The method of applying the coating liquid according to the present invention to the base paper is not particularly limited, and a known coating method can be used. For example, air knife coater, curtain coater, slide lip coater, die coater, blade coater, gate roll coater, bar coater, rod coater, roll coater, bill blade coater,
It can be coated on the base paper by various devices such as short dwell blade coater and size press.

As a means for drying after coating, a generally known method can be used and is not limited. For example,
For example, a method of transporting the heated air generated by the heat source into the warmed air blower, a method of passing it near a heat source such as a heater, and the like.

The coating amount of the coating liquid of the present invention is required to 5 g / m ² or more in terms of solid content, to allow the further effect of the present invention is preferably 7~30g / m ^2. Further, the coating liquid may be applied in two or three times.

Examples of the method of smoothing after coating include super calendar and soft calendar. The heat calendering treatment, which is performed while applying heat, is used to impart glossiness, but in the case of a matte state with a low glossy feeling, it is preferable to treat at room temperature, and in order not to impair the cushioning property, low pressure and Treatment in a short time is preferable.

[0049]

EXAMPLES The present invention will be described below with reference to examples. The present invention is not limited to the examples. All parts and% in the following are by mass.

(Base paper) As a pulp formulation, commercially available LBKP
(Freeness 350 mlcsf) 30 parts, commercial NBKP
(Freeness 420 mlcsf) 70 parts, light calcium carbonate 10% by ash content as a pigment to be incorporated, 0.03 part of other alkyl ketene dimer internal additive sizing agent, 0.2 part of commercially available cationized starch, A pulp slurry prepared by using 0.03 part of a commercially available cationic polyacrylamide retention aid was prepared using a Fourdrinier paper machine so as to have a basis weight of 64 g / m ² and a moisture content of 6% to obtain a base paper.

(Pigment Dispersion 1) 100 parts of spindle-shaped light calcium carbonate (TP-121: Okutama Kogyo Co., Ltd.), and sodium polyacrylate as a dispersant, 1 part (Aron T) for all pigments.
-40: Toagosei Kagaku Kogyo Co., Ltd.), dispersed in added water to a solids concentration of 65% using a Choles disperser, and further using a sand grinder to obtain an average bead diameter of 1.0 m.
m, a filling rate of 80%, a discharge rate of 1 liter / min, and a process of 1 pass to produce a pigment dispersion liquid 1 having an average particle diameter of 1.2 μm.

(Pigment dispersion 2) Columnar light calcium carbonate 1
00 parts (TP-123: Okutama Kogyo Co., Ltd.) and 3 parts (allon T-
40: Toagosei Kagaku Kogyo Co., Ltd.) Dispersed in added water to a solids concentration of 60% using a Choles disperser, and further using a sand grinder to obtain an average bead diameter of 1.0 m.
m, a filling rate of 80%, a discharge rate of 1 liter / min, and a process of 1 pass to produce Pigment Dispersion Liquid 2 having an average particle diameter of 1.0 μm.

(Pigment dispersion 3) Heavy calcium carbonate 100
(Carbital 90: ECC), and 0.8 parts by weight of polysodium acrylate as a dispersant (Aron T-4).
0: Toagosei Kagaku Kogyo Co., Ltd.) Dispersed in added water to a solids concentration of 70% using a Choles disperser, and further using a sand grinder, an average bead diameter of 1.0 mm,
The pigment dispersion liquid 3 having an average particle diameter of 1.5 μm was manufactured by treating under the conditions of a filling rate of 80% and a discharge rate of 1 liter / min for 1 pass.

(Pigment Dispersion Liquid 4) 100 parts of hexagonal plate-shaped magnesium carbonate (Venus: Kashima Chemical Industry Co., Ltd.) and 5 parts of sodium polyacrylate as a dispersant for all pigments (Aron T-4).
0: Toagosei Kagaku Kogyo Co., Ltd.) Dispersed in added water to a solid content concentration of 60% using a Choles disperser, and further using a sand grinder, an average bead diameter of 1.0 mm,
The pigment dispersion liquid 4 having an average particle diameter of 0.7 μm was manufactured by treating under the conditions of a filling rate of 80% and a discharge rate of 1 liter / min for 1 pass.

(Pigment dispersion 5) Columnar magnesium carbonate 10
0 parts (heavy: Kamishima Chemical Co., Ltd.), 5 parts (Aron T-40: Toagosei Kagaku Kogyo Co., Ltd.) of polyacrylic acid soda as a dispersant was added to water, and a solid content was added using a Corres Disperser The particles were dispersed to a concentration of 60%, further treated using a sand grinder under the conditions of an average bead diameter of 1.0 mm, a filling rate of 80%, an ejection rate of 1 liter / min, and one pass to obtain an average particle diameter of 1. A 5 μm pigment dispersion 5 was prepared.

(Pigment Dispersion Liquid 6) Hexagonal Plate-like Secondary Kaolin 10
Part 0 (HYDRASPERSE: JM Huber)
Was dispersed in water containing 0.1 part (Aron T-40: Toagosei Kagaku Kogyo Co., Ltd.) of sodium polyacrylate as a dispersant so as to have a solid content concentration of 70% using a Choles disperser. Then, using a sand grinder, the treatment was performed under the conditions of an average bead diameter of 1.0 mm, a filling rate of 80%, a discharge rate of 1 liter / min, and one pass, and an average particle diameter of 1.6 μm.
m pigment dispersion 6 was prepared.

(Pigment Dispersion 7) Spindle-shaped light calcium carbonate 95 parts (TP-121: Okutama Kogyo) and hexagonal plate-shaped magnesium carbonate 5 parts (Venus: Kamijima Chemical Co., Ltd.) were used as polydisperse polysodium acrylate. 4 parts for pigment (Aron T
-40: Toagosei Kagaku Kogyo Co., Ltd.) Dispersed in added water to a solids concentration of 60% using a Choles disperser, and further using a sand grinder to average bead diameter 1.0 m.
m, a filling rate of 80%, a discharge rate of 1 liter / minute, and a process of 1 pass to produce a pigment dispersion liquid 7 having an average particle diameter of 1.1 μm.

(Pigment Dispersion Liquid 8) Spindle-shaped light calcium carbonate 85 parts (TP-121: Okutama Kogyo Co., Ltd.) and hexagonal plate-shaped magnesium carbonate 15 parts (Venus: Kamijima Kagaku Kogyo Co., Ltd.) and sodium polyacrylate as a dispersant. 4 parts (Aron T-40: Toagosei Kagaku Kogyo Co., Ltd.) of the pigment was added and dispersed in water to a solids concentration of 60% using a Choles disperser, and the average bead diameter was 1 using a sand grinder. .0
mm, filling rate 80%, discharge amount 1 liter / min, 1 pass, pigment dispersion 8 having an average particle diameter of 1.0 μm.
Was manufactured.

(Pigment Dispersion 9) Spindle-shaped light calcium carbonate (70 parts) (TP-121: Okutama Kogyo) and hexagonal plate-shaped magnesium carbonate (30 parts) (Venus: Kamijima Chemical Co., Ltd.) were used as polydisperse polysodium acrylate. 4 parts (Aron T-40: Toagosei Kagaku Kogyo Co., Ltd.) of the pigment was added and dispersed in water to a solids concentration of 60% using a Choles disperser, and the average bead diameter was 1 using a sand grinder. .0
mm, filling rate 80%, discharge amount 1 liter / min, 1 pass, pigment dispersion 9 having an average particle diameter of 0.9 μm.
Was manufactured.

(Pigment Dispersion Liquid 10) Spindle-shaped light calcium carbonate 60 parts (TP-121: Okutama Kogyo Co., Ltd.) and hexagonal plate-shaped magnesium carbonate 40 parts (Venus: Kamijima Kagaku Kogyo Co., Ltd.) were used, and sodium polyacrylate was used as a dispersant. 5 parts (Aron T-40: Toagosei Kagaku Kogyo Co., Ltd.) added to the pigment was dispersed in water using a Choles disperser so that the solid content concentration was 60%.
Furthermore, using a sand grinder, the average bead diameter is 1.
Treatment was carried out under the conditions of 0 mm, a filling rate of 80%, a discharge rate of 1 liter / minute, and 1 pass to produce a pigment dispersion liquid 10 having an average particle diameter of 0.8 μm.

[Coating Paper for Gravure Printing of the First Invention] Examples 1 to 8 and Comparative Examples 1 to 6 Using the pigment dispersions prepared as described above, coating solutions were prepared as follows.

(Coating Liquid 1) Pigment Dispersion Liquid 1 in a solid content of 97 parts and Pigment Dispersion Liquid 4 in a solid content of 3 parts, and latex as an adhesive (glass transition point: −35 ° C., average particle diameter: 140 n)
m) in a solid content of 12 parts and carboxymethylcellulose as a water retention agent in a solid content of 0.1 part, and stirred, and NaOH is added to adjust the pH to 9.5, and water is added to adjust the solid content concentration to 58. % Coating liquid 1 was prepared.

(Coating Liquid 2) Pigment Dispersion Liquid 1 in 90 parts by solid content, Pigment Dispersion Liquid 4 in 10 parts by solid content, latex as an adhesive (glass transition point: −35 ° C., average particle diameter: 140 n)
m) in a solid content of 12 parts and carboxymethylcellulose as a water retention agent in a solid content of 0.1 part, and stirred, and NaOH is added to adjust the pH to 9.5, and water is added to adjust the solid content concentration to 58. % Coating liquid 2 was prepared.

(Coating Liquid 3) Pigment Dispersion 1 (80 parts by solid content), Pigment Dispersion 4 (20 parts by solid content), latex as an adhesive (glass transition point: -35 ° C., average particle diameter: 140 n)
m) in a solid content of 12 parts and carboxymethylcellulose as a water retention agent in a solid content of 0.1 part, and stirred, and NaOH is added to adjust the pH to 9.5, and water is added to adjust the solid content concentration to 58. % Coating liquid 3 was prepared.

(Coating Liquid 4) Pigment Dispersion Liquid 1 in solid content of 50 parts, Pigment Dispersion Liquid 4 in solid content of 50 parts, latex as an adhesive (glass transition point: -35 ° C., average particle diameter: 140 n)
m) in a solid content of 12 parts and carboxymethylcellulose as a water retention agent in a solid content of 0.1 part, and stirred, and NaOH is added to adjust the pH to 9.5, and water is added to adjust the solid content concentration to 58. % Coating liquid 4 was prepared.

(Coating Liquid 5) Pigment Dispersion Liquid 1 in solid content of 20 parts, Pigment Dispersion Liquid 4 in solid content of 80 parts, latex as an adhesive (glass transition point: -35 ° C., average particle diameter: 140 n)
m) in a solid content of 12 parts and carboxymethylcellulose as a water retention agent in a solid content of 0.1 part, and stirred, and NaOH is added to adjust the pH to 9.5, and water is added to adjust the solid content concentration to 58. % Coating liquid 5 was prepared.

(Coating Liquid 6) Pigment Dispersion Liquid 2 in solid content of 80 parts, Pigment Dispersion Liquid 4 in solid content of 20 parts, latex as an adhesive (glass transition point: −35 ° C., average particle diameter: 140 n)
m) in a solid content of 12 parts and carboxymethylcellulose as a water retention agent in a solid content of 0.1 part, and stirred, and NaOH is added to adjust the pH to 9.5, and water is added to adjust the solid content concentration to 58. % Coating liquid 6 was prepared.

(Coating Liquid 7) Pigment Dispersion Liquid 1 in a solid content of 80 parts, Pigment Dispersion Liquid 4 in a solid content of 20 parts, latex as an adhesive (glass transition point: -30 ° C., average particle diameter: 170 n)
m) in a solid content of 12 parts and carboxymethylcellulose as a water retention agent in a solid content of 0.1 part, and stirred, and NaOH is added to adjust the pH to 9.5, and water is added to adjust the solid content concentration to 58. % Coating liquid 7 was prepared.

(Coating Liquid 8) Pigment Dispersion Liquid 1 in a solid content of 80 parts, Pigment Dispersion Liquid 4 in a solid content of 20 parts, latex as an adhesive (glass transition point: 10 ° C., average particle diameter: 140 n)
m) in a solid content of 12 parts and carboxymethylcellulose as a water retention agent in a solid content of 0.1 part, and stirred, and NaOH is added to adjust the pH to 9.5, and water is added to adjust the solid content concentration to 58. % Coating liquid 8 was prepared.

(Coating Liquid 9) Pigment Dispersion Liquid 1 is added as solid content of 100.
Part, latex as an adhesive (glass transition point: -35
C., average particle size: 140 nm) at a solid content of 12 parts, and carboxymethyl cellulose as a water retention agent at a solid content of 0.1.
Parts and stir to adjust the pH to 9.5 with NaOH
Was added and water was added to prepare a coating liquid 9 having a solid content concentration of 58%.

(Coating Liquid 10) Pigment Dispersion Liquid 2 was added in a solid content of 10
0 part, latex as an adhesive (glass transition point: -35
C., average particle size: 140 nm) at a solid content of 12 parts, and carboxymethyl cellulose as a water retention agent at a solid content of 0.1.
Parts and stir to adjust the pH to 9.5 with NaOH
Was added and water was added to prepare a coating liquid 10 having a solid content concentration of 58%.

(Coating Liquid 11) Pigment Dispersion Liquid 3 in solid content of 80
And 20 parts by weight of the pigment dispersion 4 in solid content, latex as an adhesive (glass transition point: −35 ° C., average particle diameter: 140
nm) in solid content and 0.1 part in solid content of carboxymethyl cellulose as a water retention agent are added and stirred to adjust pH.
Was added so that the ratio was 9.5, and water was added to prepare coating liquid 11 having a solid content concentration of 58%.

(Coating Liquid 12) Pigment Dispersion Liquid 2 in solid content of 80
Parts and 20 parts by weight of pigment dispersion 5 in solid content, latex as an adhesive (glass transition point: −35 ° C., average particle size: 140
nm) in solid content and 0.1 part in solid content of carboxymethyl cellulose as a water retention agent are added and stirred to adjust pH.
To 9.5, and then water was added to prepare a coating liquid 12 having a solid content concentration of 58%.

(Coating Liquid 13) Pigment Dispersion Liquid 1 at a solid content of 80
Parts and pigment dispersion 6 in solid content 20 parts, latex as an adhesive (glass transition point: −35 ° C., average particle diameter: 140
nm) in solid content and 0.1 part in solid content of carboxymethyl cellulose as a water retention agent are added and stirred to adjust pH.
Was added so that the ratio was 9.5, and water was added to prepare coating liquid 13 having a solid content concentration of 58%.

(Coating Liquid 14) Pigment Dispersion Liquid 4 having a solid content of 10
0 part, latex as an adhesive (glass transition point: -35
C., average particle size: 140 nm) at a solid content of 12 parts, and carboxymethyl cellulose as a water retention agent at a solid content of 0.1.
Parts and stir to adjust the pH to 9.5 with NaOH
Was added and water was added to prepare a coating liquid 14 having a solid content concentration of 58%.

Using the coating liquids 1 to 14 prepared as described above, a coating speed of 1000 m / min was applied with a blade coater, and the coating amounts were 13 g / m ² and 14 g / m ^{2 on} the felt surface and the wire surface of both sides of the base paper, respectively. After coating and drying so that the water content of the coated paper is 6.0% by weight, roll surface temperature is 6
Super calendering was performed under the conditions of 0 ° C., linear pressure of 205 kg / cm and speed of 400 m / min to obtain coated papers for gravure printing of Examples 1-8 and Comparative Examples 1-6.

The coated papers for gravure printing of Examples 1 to 8 and Comparative Examples 1 to 6 were evaluated by the following evaluation methods, and the results are shown in Table 1. The methods for measuring the physical properties of the latex and pigment dispersion are also shown.

<Average particle size of pigment> Laser diffraction / scattering type Microtrack HRA particle size analyzer (Leeds
& Northrup) was used to measure the cumulative average particle size of 50%.

<Glass Transition Point> A film made of latex was prepared, 20 mg of the film was sampled, and a differential scanning calorimeter (DSC; Differential) was used.
Scanning Calorimetry), heating rate 5 ° C / min, measurement temperature range -100 to +50
The characteristic curve obtained at ° C was read by the ASTM method, and the glass transition point was calculated. (Unit: ° C)

<Average particle size of latex> Enlarged by an electron microscope to 30,000 times, the particles in the obtained micrograph were binarized by using an image analyzer, and the particle size of 1000 particles was determined by number average. It was (Unit: nm)

<Missing Dots> Printing was performed on coated paper for gravure printing using a Ministry of Finance gravure printing suitability tester,
The missing dots were measured and evaluated as XX: extremely bad, X: bad, Δ: normal, ◯: good, ⊚: extremely good. The level that can be satisfied as a gravure printed material obtained by using the coated paper for gravure printing is Δ or more.

<Roll dirt> Roll dirt length 10000
Roll surface temperature of 60 using m gravure printing coated paper
Supercalendering was carried out under conditions of ° C, linear pressure of 205 Kg / cm and speed of 400 m / min, and the degree of roll stain was evaluated with the naked eye. The evaluation is XX: extremely bad, X: bad, Δ:
Ordinarily, ◯: good, ⊚: extremely good, and the level at which there is no problem in operation is Δ or higher.

<White Paper Glossiness> The white paper glossiness of the coated paper for gravure printing of Example 3 was taken as a standard (O), and visually observed and higher than this, ⊚; The level that does not exist was evaluated as Δ, and the case where the glossiness was extremely poor was evaluated as ×.

<Whiteness> Based on JIS-P-8123, whiteness was measured using a Hunter whiteness tester. The unit of measurement is%, and the larger the number, the higher the whiteness.

[0085]

[Table 1]

As is clear from Table 1 above, the coated paper for gravure printing in the present invention is an excellent coated paper for gravure printing which is excellent in preventing the occurrence of missing dots and has less stains on the super calendar roll. . As shown in Examples 1 to 6, the higher the content of hexagonal plate-shaped magnesium carbonate, the more excellent the prevention of the occurrence of missing dots and the glossiness of the white paper, and the use of columnar light calcium carbonate is more effective. Has been obtained. As shown in Comparative Examples 1 to 6, when one or both of the light calcium carbonate and the hexagonal plate-shaped magnesium carbonate is not contained, the effect of preventing the missing dots and the stains of the super calender roll is not obtained. In addition, Example 7,
As shown in FIG. 8, it can be seen that the effect of the present invention is reduced unless the glass transition point or the average particle size of the latex is satisfied.

[Coating Paper for Gravure Printing of the Second Invention] Examples 9 to 13 and Comparative Examples 7 to 10 Using the pigment dispersions prepared as described above, coating solutions were prepared as follows.

(Coating Liquid 15) Pigment Dispersion Liquid 1 in solid content of 75
Parts, 20 parts by weight of the pigment dispersion liquid 4 in solid content, the hollow organic pigment (H
P-91: R & H company, average particle size 1.0 μm, 5 parts by solid content, latex as an adhesive (glass transition point: −3)
5 parts by weight, average particle size: 140 nm) in solid content of 12 parts, and carboxymethyl cellulose as a water retention agent in solid content of 0.
1 part was added and stirred, and NaO was added to adjust the pH to 9.5.
H was added, and water was added to give a coating liquid with a solid concentration of 55% 15
Was prepared.

(Coating Liquid 16) Pigment Dispersion Liquid 1 at a solid content of 75
Parts, 20 parts by weight of the pigment dispersion liquid 4 in solid content, the hollow organic pigment (H
P-433J: R & H Co., average particle size 0.4 μm, 5 parts by solid content, latex as an adhesive (glass transition point:
-35 ° C., average particle size: 140 nm) as solid content of 12
Parts, 0.1 parts of carboxymethyl cellulose as a water retention agent in solid content is added and stirred, and NaOH is added to adjust pH to 9.5, and water is added to form a coating liquid 16 having a solid content concentration of 55%. Prepared.

(Coating Liquid 17) Pigment Dispersion Liquid 2 in solid content of 75
Parts, 20 parts by weight of the pigment dispersion liquid 4 in solid content, the hollow organic pigment (H
P-91: R & H company, average particle size 1.0 μm, 5 parts by solid content, latex as an adhesive (glass transition point: −3)
5 parts by weight, average particle size: 140 nm) in solid content of 12 parts, and carboxymethyl cellulose as a water retention agent in solid content of 0.
1 part was added and stirred, and NaO was added to adjust the pH to 9.5.
H was added, and water was added to obtain a coating liquid 17 having a solid content concentration of 55%.
Was prepared.

(Coating Liquid 18) Pigment Dispersion Liquid 1 at a solid content of 75
Parts, 20 parts by weight of the pigment dispersion liquid 4 in solid content, the hollow organic pigment (H
P-91: R & H company, average particle size 1.0 μm, 5 parts by solid content, latex as an adhesive (glass transition point: −3)
0 ° C., average particle diameter: 170 nm) is 12 parts in solid content, and carboxymethylcellulose as a water retention agent is in solid content of 0.
1 part was added and stirred, and NaO was added to adjust the pH to 9.5.
H was added, and water was added to give a coating liquid 18 with a solid content concentration of 55%.
Was prepared.

(Coating Liquid 19) Pigment Dispersion Liquid 1 at a solid content of 75
Parts, 20 parts by weight of the pigment dispersion liquid 4 in solid content, the hollow organic pigment (H
P-91: R & H Co., average particle size 1.0 μm, 5 parts by solid content, latex as adhesive (glass transition point: 10)
C., average particle size: 140 nm) at a solid content of 12 parts, and carboxymethyl cellulose as a water retention agent at a solid content of 0.1.
Parts and stir to adjust the pH to 9.5 with NaOH
Was added and water was added to prepare a coating liquid 19 having a solid content concentration of 55%.

(Coating Liquid 20) Pigment Dispersion Liquid 1 in solid content of 95
Parts, hollow organic pigment (HP-91: R & H Co., average particle size 1.0 μm) in 5 parts by solid content, latex as an adhesive (glass transition point: −35 ° C., average particle size: 140 nm)
Is added in an amount of 12 parts in solid content, and carboxymethyl cellulose is added as a water retention agent in an amount of 0.1 part in solid content, and the mixture is stirred to adjust the pH to 9.
NaOH was added so as to be 5, and water was added to prepare a coating liquid 20 having a solid content concentration of 55%.

(Coating Liquid 21) Pigment Dispersion Liquid 3 is added in a solid content of 75
Parts, 20 parts by weight of the pigment dispersion liquid 4 in solid content, the hollow organic pigment (H
P-91: R & H company, average particle size 1.0 μm, 5 parts by solid content, latex as an adhesive (glass transition point: −3)
5 parts by weight, average particle size: 140 nm) in solid content of 12 parts, and carboxymethyl cellulose as a water retention agent in solid content of 0.
1 part was added and stirred, and NaO was added to adjust the pH to 9.5.
H was added, and water was added to obtain a coating liquid 21 having a solid content concentration of 55%.
Was prepared.

(Coating Liquid 22) Pigment Dispersion Liquid 2 in solid content of 75
Part, 20 parts of the pigment dispersion 5 in terms of solid content, a hollow organic pigment (H
P-91: R & H company, average particle size 1.0 μm, 5 parts by solid content, latex as an adhesive (glass transition point: −3)
5 parts by weight, average particle size: 140 nm) in solid content of 12 parts, and carboxymethyl cellulose as a water retention agent in solid content of 0.
1 part was added and stirred, and NaO was added to adjust the pH to 9.5.
H was added, and water was added to obtain a coating liquid 22 having a solid content concentration of 55%.
Was prepared.

(Coating Liquid 23) Pigment Dispersion Liquid 4 was added to a solid content of 95
Parts, hollow organic pigment (HP-91: R & H Co., average particle size 1.0 μm) in 5 parts by solid content, latex as an adhesive (glass transition point: −35 ° C., average particle size: 140 nm)
Is added in an amount of 12 parts in solid content, and carboxymethyl cellulose is added as a water retention agent in an amount of 0.1 part in solid content, and the mixture is stirred to adjust the pH to 9.
NaOH was added so as to be 5, and water was added to prepare a coating liquid 23 having a solid content concentration of 55%.

Using the coating liquids 15 to 23 prepared as described above, a coating speed of 1000 m / min was applied with a blade coater, and the coating amounts were 13 g / m ² and 14 g / m ^{2 on} the felt surface and the wire surface of both sides of the base paper, respectively. After coating and drying so that the water content of the coated paper is 6.0% by weight, roll surface temperature is 6
Super calendering was performed under the conditions of 0 ° C., linear pressure of 205 Kg / cm and speed of 400 m / min to obtain coated papers for gravure printing of Examples 9 to 13 and Comparative Examples 7 to 10.

The coated papers for gravure printing of Examples 9 to 13 and Comparative Examples 7 to 10 were evaluated by the above evaluation method, and the results are shown in Table 2.

[0099]

[Table 2]

Table 2 shows the case where a hollow organic pigment was further contained as a coating pigment, and Examples 9 and 11 to 13 are more excellent in the effect of preventing missing dots than Examples 1 to 6. You can see that If the particle size of the hollow organic pigment is smaller than 0.5 μm, the effect is slightly reduced. Similar to Comparative Examples 1 to 6, Comparative Examples 7 to 10
Also in the above, the effect of preventing the missing dots and the stain of the super calendar roll is not obtained.

[Method for Producing Coated Paper for Gravure Printing] Examples 14 to 21 Coating solutions were prepared as follows using the pigment dispersions prepared as described above.

(Coating Liquid 24) Pigment Dispersion Liquid 7 was added in a solid content of 10
0 part, latex as an adhesive (glass transition point: -35
C., average particle size: 140 nm) at a solid content of 12 parts, and carboxymethyl cellulose as a water retention agent at a solid content of 0.1.
Parts and stir to adjust the pH to 9.5 with NaOH
Was added and water was added to prepare a coating liquid 24 having a solid content concentration of 58%.

(Coating Liquid 25) Pigment Dispersion Liquid 8 was added in a solid content of 10
0 part, latex as an adhesive (glass transition point: -35
C., average particle size: 140 nm) at a solid content of 12 parts, and carboxymethyl cellulose as a water retention agent at a solid content of 0.1.
Parts and stir to adjust the pH to 9.5 with NaOH
Was added and water was added to prepare a coating liquid 25 having a solid content concentration of 58%.

(Coating Liquid 26) Pigment Dispersion Liquid 9 was added in a solid content of 10
0 part, latex as an adhesive (glass transition point: -35
C., average particle size: 140 nm) at a solid content of 12 parts, and carboxymethyl cellulose as a water retention agent at a solid content of 0.1.
Parts and stir to adjust the pH to 9.5 with NaOH
Was added and water was added to prepare a coating liquid 26 having a solid content concentration of 58%.

(Coating Liquid 27) Pigment Dispersion Liquid 10 in solid content of 1
00 parts, latex as an adhesive (glass transition point: -3
5 parts by weight, average particle size: 140 nm) in solid content of 12 parts, and carboxymethyl cellulose as a water retention agent in solid content of 0.
1 part was added and stirred, and NaO was added to adjust the pH to 9.5.
H is added, and water is added to the coating liquid 27 having a solid concentration of 58%.
Was prepared.

(Coating Liquid 28) Pigment Dispersion Liquid 1 is mixed in a solid content of 95
Parts, 5 parts of pigment dispersion 4 in solid content, latex as an adhesive (glass transition point: −35 ° C., average particle diameter: 140 n
m) in a solid content of 12 parts and carboxymethylcellulose as a water retention agent in a solid content of 0.1 part, and stirred, and NaOH is added to adjust the pH to 9.5, and water is added to adjust the solid content concentration to 58. % Coating liquid 28 was prepared.

(Coating Liquid 29) Pigment Dispersion Liquid 1 at 85% solids
Parts, 15 parts by weight of the pigment dispersion 4 in solid content, latex as an adhesive (glass transition point: −35 ° C., average particle diameter: 140
nm) in solid content and 0.1 part in solid content of carboxymethyl cellulose as a water retention agent are added and stirred to adjust pH.
To 9.5, and water was added to prepare a coating liquid 29 having a solid content concentration of 58%.

(Coating Liquid 30) Pigment Dispersion Liquid 1 at a solid content of 70
Parts, 30 parts by weight of pigment dispersion 4 in solid content, latex as an adhesive (glass transition point: −35 ° C., average particle diameter: 140
nm) in solid content and 0.1 part in solid content of carboxymethyl cellulose as a water retention agent are added and stirred to adjust pH.
Was added so that the ratio was 9.5, and water was added to prepare a coating liquid 30 having a solid content concentration of 58%.

(Coating Liquid 31) Pigment Dispersion Liquid 1 at a solid content of 60
Parts, 40 parts by weight of the pigment dispersion 4 in solid content, latex as an adhesive (glass transition point: −35 ° C., average particle diameter: 140
nm) in solid content and 0.1 part in solid content of carboxymethyl cellulose as a water retention agent are added and stirred to adjust pH.
To 9.5, and water was added to prepare a coating liquid 31 having a solid content concentration of 58%.

Using the coating liquids 24 to 31 prepared as described above, a blade coater was applied at a coating speed of 1000 m / min, and the coating amounts were 13 g / m ² and 14 g / m ^{2 on} the felt surface and the wire surface of both sides of the base paper, respectively. After coating and drying so that the water content of the coated paper is 6.0% by weight, roll surface temperature is 6
Super calendering was performed under the conditions of 0 ° C., linear pressure of 205 Kg / cm, and speed of 400 m / min to produce coated papers for gravure printing of Examples 14 to 21.

The coated papers for gravure printing produced in Examples 14 to 21 were evaluated by the above-described evaluation method and the following evaluation method, and the results are shown in Table 3.

<Streak> The coating surface quality immediately after scraping off the coating liquid with a blade with a blade coater was observed,
The number of streak occurrences per 1 m of width was counted, and the same operation was repeated 3 times to obtain the average value as the number of streak occurrences. The evaluation is ◎: 0 occurrences, ○: 3 occurrences
Below this, Δ: The number of generated lines is 5 or less, ×: The number of generated lines is 6 or more, and the level that does not cause a problem in operation is Δ or more.

<High shear viscosity> ACA System
A capillary viscometer (ACAV) manufactured by s Oy was used, and the measurement conditions were a pressure of 2000 Pa and a capillary inner diameter of 0.5 mm. The unit of measurement is mPa · s, and the larger the number, the higher the viscosity.

[0114]

[Table 3]

Table 3 shows a comparison between Examples 14 to 17 in which light calcium carbonate and hexagonal plate-shaped magnesium carbonate are co-dispersed and Examples 18 to 21 in which they are individually dispersed. The high shear viscosity is high due to the re-aggregation of light calcium carbonate, and streak is significantly generated, but since coagulation prevents re-aggregation,
It can be seen that the high shear viscosity is low and no streak has occurred.

[0116]

The coated paper for gravure printing of the present invention contains light calcium carbonate and hexagonal plate-shaped magnesium carbonate as coating pigments, and by using the glass transition point and average particle diameter of latex within a specific range. It also has excellent gravure printing suitability by improving the missing dots and improving the coating strength to prevent it from adhering to the surface of the super calender roll, and by co-dispersing the coating pigment, it also improves operability. It is also an excellent manufacturing method.

Claims (7)

[Claims] 1. A coated paper for gravure printing, which comprises coating a coating solution containing a pigment and an adhesive as a main component on both sides or one side of a base paper mainly containing wood pulp, wherein the pigment is a light calcium carbonate. And coated paper for gravure printing, which is hexagonal plate-shaped magnesium carbonate. 2. A coated paper for gravure printing, which is obtained by applying a coating liquid containing a pigment and an adhesive as a main component on both sides or one side of a base paper mainly composed of wood pulp, wherein the pigment is light calcium carbonate. , Hexagonal plate-shaped magnesium carbonate, and a hollow organic pigment having an average particle diameter of 0.5 μm or more, a coated paper for gravure printing. 3. The coated paper for gravure printing according to claim 1, wherein the light calcium carbonate is in the form of spindle or column, or both. 4. The coated paper for gravure printing according to claim 1, wherein the adhesive is a latex having a glass transition temperature of −30 ° C. or lower and an average particle diameter of 150 nm or lower. 5. The gravure printing according to any one of claims 1 to 4, wherein the content ratio of the light calcium carbonate and the hexagonal plate-shaped magnesium carbonate is 1: 1 to 1: 0.05. Coated paper. 6. The method for producing a coated paper for gravure printing according to claim 1, wherein the base paper is coated with a coating solution containing light calcium carbonate and hexagonal plate-shaped magnesium carbonate, and after drying, A method for producing coated paper for gravure printing, which comprises producing by smoothing. 7. The coating solution, after codispersing light calcium carbonate and hexagonal plate-shaped magnesium carbonate in water, has an average particle size of 1.
The method for producing a coated paper for gravure printing according to claim 6, which comprises pulverizing to a size of 5 μm or less.