JP2002138392A - Mat coated paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a mat coated paper high in bulkiness (low density), excellent in flexibility, having high printing glossiness of image area in spite of low glossiness of white paper, low in fine uneven brightness of the image area and excellent workability in a printing machine. SOLUTION: This mat coated paper having a coated layer comprising a pigment and a binder, comprises the pigment having particle size distribution of >=65% in the range of 0.4 to 4.2 μm in volume base and the product of four factors of basis weight of the coated paper, density, Young's modulus of the paper in paper making direction and breaking length in paper making direction lays between 1.0×1021 g2N/m6 to 4.0×1021 g2N/m6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coated paper for printing, which is bulky (low density) and excellent in flexibility, and has high printing glossiness in an image area despite low white paper glossiness. The present invention relates to a matt coated paper which has a small minute unevenness in gloss in an image area and has good workability in a printing machine.

[0002]

2. Description of the Related Art In recent years, visualization and colorization of printed matter have been advanced, and demand for higher quality of printing paper has been increased. On the other hand, there is also a high demand for weight reduction of printed materials in order to reduce transportation and mailing costs. Conventionally, these two demands are contradictory, and high-quality print-coated paper has a large basis weight and coating amount of base paper, and has a higher density compared to the same basis weight due to smoothing by surface treatment. Was something. To reduce the weight of the printed matter, it is possible to select a paper having a low basis weight. However, if the density is the same, the paper thickness decreases with the weight reduction, and the volume feeling of the booklet is deteriorated. For this reason, a high-quality coated paper that is bulky, that is, has a higher paper thickness compared with the same basis weight or a lower basis weight as compared with the same paper thickness, and satisfies the requirements of coated paper for high-grade printing applications. It has been demanded.

[0003] In recent years, there has been a tendency to prefer information magazines called mooks and pocket guides, which are small in size and easy to carry. Flexibility is important as a characteristic required for these papers. When rigid paper is used, the smaller the plate, the easier it is to stand up when turning the pages of the booklet, and it is very inconvenient to open and read the booklet with one hand, for example, on the go. As an indicator of paper flexibility,
Clark stiffness etc. are used, the lower one is more flexible,
Stiffness increases in proportion to the cube of the paper thickness. When the paper thickness is increased at the same basis weight due to the bulkiness, the stiffness increases with the increase, and it is extremely difficult to achieve both the flexibility and the bulkiness of the paper.

[0004] As a technique for increasing the bulk, there are techniques for increasing the bulk of the base paper for coated paper by using a bulky pulp and a bulky filler, reducing the coating amount of the coating liquid composition, and obtaining the surface of the coated paper obtained. Relaxation of processing is used.

[0005] As pulp for papermaking, there are chemical pulp obtained by extracting lignin in fibers with chemicals, groundwood pulp obtained by grinding wood with a grinder without using chemicals, and thermomechanical pulp obtained by disintegrating wood with a refiner. Mechanical pulp. In general, mechanical pulp has stiffer fibers and bulkier (lower density) than chemical pulp
It is effective for conversion. However, these mechanical pulp have quality problems such as low whiteness when blended with high quality paper, and even with medium quality paper, the amount of blending is limited due to the tendency of printing defects such as paper scorching due to binding fibers. There is. In addition, wastepaper pulp is increasingly used in recent years because of the growing tendency to protect the environment and the need to protect resources. However, waste paper pulp is generally mixed with high-quality paper, newsprint, magazines, coated paper, etc., and is often pulped. Therefore, compared to virgin (unused paper pulp) mechanical pulp, High density, not bulky. As described above, it is difficult to achieve sufficient bulking of the paper only on the pulp surface in consideration of protection of wood resources and quality design of the paper. In addition, it is impossible to impart sufficient flexibility to the paper because only the above-mentioned pulp is blended and the rigidity is increased together with the bulkiness.

[0006] Further, use of a bulky filler is considered as bulking of the base paper for coated paper. For example, JP-A-5-339898 discloses a method of lowering the density by blending a hollow synthetic organic substance capsule. However, such a synthetic organic substance lowers paper strength, so that there are problems such as paper scorching and paper breakage at the time of printing, and it is necessary to use a high blending ratio in order to obtain a sufficient bulking effect, thereby increasing the manufacturing cost. There were also problems such as. JP-A-52-74001 proposes a method using a shirasu balloon. However, this has a problem that the mixing property with paper pulp is poor, and that the paper containing the pulp also causes uneven printing. Further, it has not been possible to impart flexibility to paper even by using the above method.

[0007] Since the coating layer of the coated paper is generally higher in density than that of the base paper, the density of the coated paper is higher than that of printing paper having no coating layer. For this reason, bulking of the coated paper can also be achieved by reducing the coating amount of the coating composition. This is because the ratio of the coating layer to the entire coated paper becomes small. However, reducing the number of coating layers at the same time reduces the coverage of the base paper with the coating layers, and reduces the printing quality such as white paper gloss, smoothness, and printing gloss. However, there is a limit to reducing the coating amount.

[0008] In order to improve the print quality of coated paper, in particular, the ink deposit density and the glossiness of the image area (hereinafter referred to as print glossiness), it is effective to increase the smoothness of the coated paper. It is one of the means. For this reason, it is common to apply a surface smoothing treatment such as a super calender or soft nip calender on coated papers with a blank white glossiness between glossy coated paper and glossy paper called glossy paper or dull tone. It is. But,
Since these treatments increase the smoothness of the surface by pressing the paper, the thickness of the paper is reduced at the same time, and it may not be possible to achieve sufficient bulkiness to obtain the target print quality.

[0009] Since the general purpose of the method for producing matte coated paper is mainly to suppress the glossiness of white paper, pigments used in paints having a large average particle size have been used. For example, as disclosed in JP-A-8-60597, 30 parts by weight of the pigment in the coating material is escalon 1500 (average particle diameter 1.65 μm) of heavy calcium carbonate,
50 parts by weight are mainly composed of secondary kaolin hydra sparse (average particle diameter 1.61 μm) and a pigment having a large average particle diameter. It was difficult to increase.

On the other hand, dull-coated paper is generally a matte-coated paper that has been subjected to a slight surface treatment and has a higher print glossiness than matte-coated paper. When a higher print gloss is targeted, it is necessary to enhance the surface treatment conditions, and it is difficult to maintain the volume feeling of the paper due to the low density, like the matt coated paper. For example, as disclosed in Japanese Patent Application Laid-Open No. H7-119086, by increasing the surface roughness of a roll of a super calender generally used as a surface treatment device, the smoothness can be reduced while suppressing the glossiness of white paper. There is a technique to increase
However, when calendering is performed with six or more rolls, the density of the paper is increased and the bulk is lost, so that the intended bulky matte coated paper cannot be obtained.

As a method of improving the printing glossiness while keeping the density low and keeping the white paper glossiness low, there is a use of a calender made of a combination of a metal roll having a rough surface and a resin roll. For example, JP-A-6-73685, JP-A-6-73686, JP-A-6-73697
And Japanese Patent Application Laid-Open No. 7-238493, use a metal roll having a rough surface,
The surface treatment is performed at a temperature of 00 ° C. or higher. However, even with these techniques, it was difficult to obtain the bulky printing paper aimed at in the present invention.

As described above, the conventional technology alone or in combination alone is bulky (low density) and excellent in flexibility, and despite the low glossiness of white paper, the printing glossiness of the image area is high. Also, there is little fine gloss unevenness in the image area,
It was impossible to obtain a coated printing paper having good workability in a printing press.

[0013]

SUMMARY OF THE INVENTION In view of such circumstances, an object of the present invention is to improve the flexibility while being bulky.
Despite the low glossiness of blank paper, the matte coating has high printing glossiness (the glossiness of the image area of the printed matter), has little fine unevenness in the image area, and has good workability in the printing press. To provide paper.

[0014]

Means for Solving the Problems The present inventors have conducted intensive studies in the above difficult situation, and as a result, have found that a matte coated paper containing a pigment and an adhesive on a base paper has a pigment volume basis. It has a particle size distribution of 65% or more in the range of 0.4 to 4.2 μm, and the product of the basis weight, density, breaking length in the papermaking direction and Young's modulus of the paper is 1.0 × 10 4 ²¹ g ²・ N
/ M ⁶ or more and 4.0 × 10 ²¹ g ² · N / m ⁶ or less, it is bulky, excellent in flexibility and low in glossiness of white paper despite low glossiness in white paper. It has been found that a matte coated paper having a high image area glossiness of printed matter, a small minute gloss unevenness of the image area (print surface feeling), and a good workability in a printing machine can be obtained. In the present invention, kaolin having a particle size distribution of 65% or more contained in the range of 0.4 to 4.2 μm on a volume basis is preferably used as the pigment in an amount of 20 parts by weight or more per 100 parts by weight of the pigment, more preferably. It is at least 50 parts by weight, more preferably at least 70 parts by weight.

The present invention will be described in detail.

The present inventors paid attention to the ease of turning a booklet when examining the flexibility of paper. Generally, the stiffness of paper is quantitatively evaluated in terms of clarity, pure bending stiffness, and the like. As a result of investigating the correlation between the ease of page turning by the subject and the pure bending stiffness in the papermaking direction and width direction for various booklets, paper with low stiffness tended to be flexible, but even if stiffness was equal Some papers had different sensory evaluations of the ease of turning pages. That is, it was found that the flexibility of the paper cannot be evaluated only by the bending stiffness.

When a page is turned, a bending stress is applied to the sheet, and a tensile stress is applied to the convex surface and a compressive stress is applied to the concave surface. Therefore, the correlation between the Young's modulus in the width direction and the papermaking direction and the ease of turning was determined. As a result, it was confirmed that even when the pure bending stiffness in the width direction was equal, the pages were more likely to turn as the Young's modulus in the width direction and the papermaking direction were lower. In many papers tested, the Young's modulus in the width direction and the papermaking direction had a positive correlation, but especially when the Young's modulus in the papermaking direction was low, the page was easy to turn and was flexible, and in addition, printing on an offset rotary press At this time, it was found that the fluctuation of the tension in the paper feeding section, the cooling roll section, and the like was small, so that the running stability of the paper web was increased and the paper breakage was hard to occur.

The present inventors have also investigated the relationship between paper strength and flexibility. As a result, it was found that, when comparing papers having the same paper thickness, paper having a shorter tearing length tends to have higher flexibility. For example, in the case of paper having a long tearing length, the amount of hydrogen bonds formed between the pulp fibers in the paper is large, and the paper strength tends to be relatively strong. It is considered that the bending stress or the tensile stress required to obtain the bending strain or the tensile strain becomes relatively large, which makes it difficult to turn the page.

From the above, it can be seen that by simultaneously reducing the Young's modulus and the breaking length of the paper in a well-balanced manner, the bulkiness and the flexibility of the paper are improved. Is also applicable. As a result of further intensive studies, the range of Young's modulus and tear length at which the desired flexibility can be obtained depends on the density and basis weight. The higher the basis weight of paper, the lower the Young's modulus or tear length must be reduced. , Good flexibility could not be obtained. That is, it was found that the flexibility of the paper showed a good correlation with the product of the basis weight, density, Young's modulus in the papermaking direction, and the breaking length in the papermaking direction. The product of the four is 1.0 × 1
0 ²¹ g ² · N / m ⁶ or more and 4.0 × 10 ²¹ g ² · N / m ⁶ or less,
Preferably 2.0 × 10 ²¹ g ² · N / m ⁶ or more and 3.5 × 1
In the range of 0 ²¹ g ² · N / m ⁶ or less, it is easy to turn a page when a printed matter is bound and made into a booklet, and because it is bulky, there is a sense of volume. It has been found that it is a coated paper for printing which has little generation of paper and the like and has good workability. Flexibility that could not be obtained by increasing the bulk of paper by the conventional technology alone or in combination is achieved by reducing the Young's modulus and the breaking length in a well-balanced manner, and the paper with good workability in a printing press is obtained. Was done.

Compared with the same basis weight, paper having a normal density and a product of four products less than 1.0 × 10 ²¹ g ² · N / m ⁶ has an excessively low Young's modulus. Or, because the tear length is too short, the paper is too flexible, so it is difficult to turn the page because it is too flexible, or the paper strain increases due to the tension in the printing press, and the paper that has exceeded the elastic limit is broken. The paper is easily cut. Further, when the paper has a normal value of Young's modulus and a breaking length of less than 1.0 × 10 ²¹ g ² · N / m ⁶ at the same basis weight, the density is excessively high. Since the paper is low, it is necessary to extremely reduce the pressure of the press and calendering in the paper making process, and therefore, the smoothness is extremely low and the print quality is inferior.

On the other hand, compared with the same basis weight, paper having a normal density and a product value of the product of the four exceeding 4.0 × 10 ²¹ g ² · N / m ⁶ is excessively torn. Long paper or high Young's modulus means that the paper is rigid and flexible paper cannot be obtained.In addition, if the Young's modulus is high, the paper becomes rigid. Troubles such as paper breakage are likely to occur because high stress is applied.
Further, the paper having a normal value of Young's modulus and a breaking length of more than 4.0 × 10 ²¹ g ² · N / m ⁶ when compared with the same basis weight has an extremely high density. That is, the printing paper is not bulky and voluminous, which is the object of the present invention.

However, even when the basis weight, density, Young's modulus in the papermaking direction, and tear length in the papermaking direction of the paper are specified in the above ranges, the glossiness of the white paper intended in the present invention is low. No matte coated paper having high print gloss (gloss in the image area of the printed matter) and good fine gloss unevenness (print surface feeling) in the image area was obtained.

Therefore, the present inventors have further studied the coating composition. As a result, it has been found that the distribution of the particle diameter of the pigment particles is narrow, that is, the narrowing of the particle size distribution improves the coverage of the base paper with the coating layer.

In general, inorganic pigments for coating compositions are not substantially uniform in particle size as in organic synthetic particles, for example, plastic pigment, but are mixed with fine particles or coarse particles, so that the particle size of the inorganic pigment is small. Wide distribution. In the case of monodispersion in which the particle diameter is the same as spherical particles, the packing ratio of the particles is the same regardless of the particle diameter, but polydispersion, for example, in a mixed system of spheres having two different particle diameters, The packing density of the particles depends on the ratio of the large particle size to the small particle size, the mixing ratio of the two types of particles, and the like. The smaller the particle size ratio (the value of the particle size of the small particles / the value of the particle size of the large particles), the smaller the packing density. The filling rate is higher. Therefore, the coating layer made of a pigment having a narrow particle size distribution has a large particle size of small particles or a small particle size of large particles as compared with those having a wide particle size distribution, or the filling rate of the pigment particles is low due to both effects. It was considered that the density of the coating layer became low.

In the case of coated paper, it is effective to increase the amount of coating in order to improve the coverage of the base paper with the coating layer. However, when the target is a bulky coated paper, it is compared with the base paper. Increasing the ratio of the coating layer having a high density is not suitable because it increases the density of the coated paper. In order to improve the smoothness of the base paper by the coating layer compared with the same coating amount, it is necessary to lower the density of the coating layer. Therefore, in the coating layer which is a mixture of particles having a large number of particle diameters, it is considered that lowering the filling rate of the pigment particles lowers the density of the coating layer and improves the coatability of the base paper.

Therefore, by defining the particle size distribution of the pigment particles contained in the coating layer, high glossiness with high printing glossiness and good print surface feeling is obtained despite low glossiness on white paper. It was found that an erased coated paper could be obtained. That is, by making the particle size distribution such that the pigment particles in the coating layer contain 65% or more in the range of 0.4 to 4.2 μm on a volume basis, the coatability of the base paper by the coating layer is greatly improved. By adding 20 parts or more of kaolin having a particle size distribution of 65% or more in the range of 0.4 to 4.2 μm on a volume basis in the coating layer, a matt coated paper having better coatability can be obtained. I found that I can be. This means that in addition to forming a bulky coating layer with a low packing density of particles, the plate-like kaolin particles cover minute voids existing on the surface of the base paper, thereby suppressing the intrusion of pigments and improving the covering properties of the base paper. Is considered to be greatly improved.

When the proportion of particles in the coating composition in the range of 0.4 to 4.2 μm on a volume basis is less than 65% and contains many small particles, the packing density of the particles is In addition, these particles enter into the minute voids on the base paper surface and do not remain on the base paper surface layer, so the base paper coverage is poor and the print gloss is low, and the fine gloss unevenness is large and the printing surface feel is large. Is inferior. When the proportion of particles falling within the range of 0.4 to 4.2 μm on a volume basis is less than 65% and contains many particles having a large particle diameter, the proportion of particles entering minute voids on the base paper surface is small. However, since the packing density of the particles increases and the smoothness decreases due to the coarse particles, the glossiness of white paper and the glossiness of printing are reduced, and fine gloss unevenness is large and the printing surface feeling is inferior. The volume particle size distribution of the pigment of the present invention was measured using a laser diffraction / scattering type particle size distribution measuring method (manufactured by Malvern Co., Ltd., laser diffraction / scattering type particle size distribution analyzer: Mastersizer S).
It is a measurement of the volume particle size distribution of the particles.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION The product of the basis weight, density, Young's modulus, and tear length of paper is 1.0 × 10 ²¹ g ² · N / m ⁶ or more and 4.0 × 10 ²¹ g ² · m. In order to reduce the density to N / m ⁶ or less, it is preferable to combine means for reducing the density of the paper, the Young's modulus in the papermaking direction, and the tear length in the papermaking direction.
Methods for reducing the density of paper include improving the mixing ratio of low-density pulp and low-density filler, using bulky chemicals, or reducing the press pressure in the papermaking process and the processing linear pressure of machine calenders. No. As a method for lowering the Young's modulus of the paper in the papermaking direction, use of a softening agent and the like can be mentioned. As a method of reducing the breaking length in the papermaking direction of the paper, a method of increasing the compounding ratio of the filler or the like is used.

In the present invention, the kind of pulp blended in the base paper is, for example, hardwood kraft pulp (hereinafter referred to as LBK).
P), softwood kraft pulp (hereinafter, referred to as NBKP), thermomechanical pulp, groundwood pulp, waste paper pulp and the like. In order to improve the coatability and suppress uneven gloss, it is preferable to use chemical pulp such as hardwood kraft pulp and softwood kraft pulp.

As the filler used in the present invention, known fillers such as heavy calcium carbonate, light calcium carbonate, kaolin, clay, talc, hydrated silica, white carbon, titanium oxide, and synthetic resin filler are used. I can do things. The amount of the filler used is preferably 6% by weight or more, more preferably 10% by weight or more, based on the weight of the pulp in order to reduce the Young's modulus. Further, if necessary, a sulfuric acid band, a sizing agent, a paper strength enhancer, a softening agent, a bulking agent, a retention improver, a coloring pigment, a dye, an antifoaming agent and the like may be contained.

The softening agent used in the present invention has an effect of inhibiting the binding between pulp fibers or softens the fibers themselves. For example, a compound having a hydrophobic group and a hydrophilic group, such as an oil-based nonionic surfactant, a sugar alcohol-based nonionic surfactant, a sugar-based nonionic surfactant, a polyhydric alcohol-type nonionic surfactant, Alcohol, ester compound of polyhydric alcohol and fatty acid, polyoxyalkylene adduct of higher alcohol or higher fatty acid, polyoxyalkylene adduct of higher fatty acid ester, polyoxyalkylene adduct of polyhydric alcohol and fatty acid ester compound, fatty acid polyamide Amines and the like can be used. It is preferable to be able to decrease the pure bending stiffness and the density in addition to decreasing the Young's modulus, and it is preferable to use an ester compound of a polyhydric alcohol and a fatty acid.

Further, a surface treatment agent containing a water-soluble polymer as a main component may be applied to the base paper for the purpose of improving the surface strength and size as long as the density, the Young's modulus and the breaking length are not affected. . As the water-soluble polymer, oxidized starch, hydroxyethyl etherified starch, enzyme-modified starch, polyacrylamide, polyvinyl alcohol, and the like, which are commonly used as surface treatment agents, can be used alone, or a mixture thereof can be used. . In addition to the water-soluble polymer, a paper strength enhancer for improving water resistance and surface strength and an external sizing agent for imparting size can be added to the surface treating 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 metaling size press coater, and a film transfer type roll coater such as a shim sizer. In addition, the pH of the coated paper base paper for printing used in the present invention
May be acidic, neutral or alkaline.

In the present invention, a coating layer having a pigment and an adhesive is provided on the base paper within a range that does not affect the density, the Young's modulus, and the breaking length.

Kaolin, clay, delaminated clay, heavy calcium carbonate, light calcium carbonate, talc, titanium dioxide, barium sulfate, calcium sulfate conventionally used for coated paper as a pigment used in the coated layer Inorganic pigments such as zinc oxide, silicic acid, silicates, colloidal silica, and satin white; and organic pigments such as plastic pigments. These pigments have a particle size of 0.4 to 4 on a volume basis in the coating composition. One or more types can be selected and used as needed within a range having a particle size distribution of 65% or more in a range of 0.2 μm.

The adhesive used in the present invention is a styrene-butadiene-based, styrene-acrylic, ethylene-vinyl acetate-based adhesive conventionally used for coated paper.
Butadiene / methyl methacrylate, vinyl acetate / butyl acrylate and other copolymers and polyvinyl alcohol, maleic anhydride copolymer, acrylic acid / methyl methacrylate copolymer and other synthetic adhesives, casein, soy protein, Synthetic proteins such as proteins, oxidized starch, positive starch, urea phosphate esterified starch, etherified starch such as hydroxyethyl etherified starch, starches such as dextrin, and cellulose derivatives such as carboxyethyl cellulose, hydroxyethyl cellulose, and hydroxymethyl cellulose. One or more kinds of adhesives for coated papers are appropriately selected and used. These adhesives are pigment 100
5 to 50 parts by weight per part by weight, more preferably 5-2
Used in a range of about 5 parts by weight. In addition, if necessary, various assistants, such as dispersants, thickeners, water retention agents, defoamers, water-proofing agents, coloring agents, and printability improvers, which are blended in a normal coating composition for coated paper. Agents are used as appropriate.

The coating layer provided on the base paper may be provided as a single layer or two or more layers on one or both sides of the base paper as long as the coating does not affect the density, Young's modulus and breaking length. The coating amount of the coating layer of the present invention is preferably a per side 8~25g / m ^2, more preferably 10 to 20 g / m ^2.

As a method for applying the coating composition to the base paper, a film such as a two-roll size press coater, a gate roll coater, a blade metaling size press coater, a rod metaling size press coater, a shim sizer or the like can be used. Transfer type roll coater, flooded nip / blade coater, jet fountain / blade coater, short dwell time application coater, rod metering coater using grooved rod, plain rod, etc. instead of blade, curtain It can be coated with a known coater such as a coater and a die coater.

Further, in order to improve the smoothness of the paper and the print quality, the coated paper obtained by the above-mentioned method can be subjected to a surface treatment within a range not affecting the density. As a surface treatment method, a known surface treatment device such as a super calender using a cotton roll as an elastic roll or a soft nip calender using a synthetic resin roll as an elastic roll can be used. The soft nip calender can be set at a high temperature because the heat resistance temperature of the surface of the synthetic resin roll can be set higher than that of the cotton roll. When the same smoothness is targeted, the processing linear pressure can be set lower than that of the super calender in some cases, so that a coated paper with lower density and higher smoothness can be obtained, which is preferable. The printing coated paper of the present invention preferably has a density of 1.00 g /
The effect is more remarkable at cm ³ or less, more preferably at 0.90 g / cm ³ or less.

[0039]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. Unless otherwise specified, parts and% in the examples indicate parts by weight and% by weight, respectively.
The selected coated printing papers were tested based on the following evaluation methods. <Evaluation method> (Pigment volume particle size distribution measurement) The volume particle size distribution of the particles was measured using a laser diffraction / scattering type particle size distribution analyzer (Malvern Co., Ltd., device name: Mastersizer S), and from 0.4 μm. The percentage of particles falling in the 4.2 μm range was calculated. (Basic weight) According to JIS P 8124: 1998. (Density) According to JIS P 8118: 1998. (Young's Modulus) According to JIS P 8113: 1998, the tensile modulus was measured and defined as the Young's modulus. (Tear length) According to JIS P 8113: 1998. (Coverability) The coated paper was immersed in a burnout treatment solution (2.5% ammonium chloride, 50% isopropyl alcohol aqueous solution) for 2 minutes, air-dried, and then dried in a blow dryer at 200 ° C.
Heat treatment was performed for 0 minutes. The uneven coloring caused by the uneven coating amount of the sample was monitored by 10 monitors.
The evaluation was made in four grades: excellent, poor, slightly poor, and poor. (Blank glossiness) According to JIS P8142: 1998. (Print Gloss) Using a RI-II type printing tester, a sheet-fed process ink manufactured by Toyo Ink Mfg. Co., Ltd. (trade name: TK)
Printing was performed using 0.30 cc of High Echo Red (MZ), and after standing overnight, the surface of the obtained printed material was subjected to JIS P
8142: 1998. (Gloss unevenness) Fine gloss unevenness on the surface of the white paper was evaluated by a monitor of 10 persons on a scale of 4: 優 れ very excellent, ○ excellent, △ slightly inferior, × poor. (Flexibility: ease of turning pages) 100 blank sheets A
Cut to 5 size, create a booklet model by clipping, and turn the pages when turning the pages with 10 monitors. ◎ Excellent, ○ Excellent, △ Slightly problematic, × Problem Was evaluated in four steps. (Workability in printing machine) The sample winding was performed by an offset rotary printing machine at a printing speed of 250 m / min.
000m length is printed, and the tension fluctuation of the infeed part and the cooling part during printing is indicated by ○ small, △ slightly large, ×
Those which are large or cause paper breakage were evaluated in three stages of x. [Example 1] 100 chemical pulp as pulp for papermaking
Parts, 12 parts of light calcium carbonate as filler, and ester compound of polyhydric alcohol and fatty acid (KB-
110, manufactured by Kao Corporation) with a basis weight of 64
g / m < ² > base paper, as a pigment, kaolin from Brazil (manufactured by Rio Capim, Capim DG, volume distribution particle size 0.40
4.20 μm: 71.7%) 100 parts of pigment (volume distribution particle size: 0.40 to 4.20 μm: 71.7%)
0.1 part of sodium polyacrylate as a dispersant, 11 parts of carboxy-modified styrene-butadiene latex as a binder, 3 parts of phosphorylated esterified starch, and further, water were added to adjust the coating solution to a concentration of 65%. Coating was performed on both sides with a blade coater at a coating speed of 800 m / min so that the amount was 14 g / m ² per side, to obtain a matte coated paper. [Example 2] 20 parts of heavy calcium carbonate (FMT-90, volume distribution particle diameter: 0.40 to 4.20 µm: 71.7%) as a pigment contained in the coating liquid,
Kaolin from Brazil (Riocapim, Capim DG, volume distribution particle size 0.40 to 4.20 μm: 71.7%) 80
Part of pigment (volume distribution particle size, 0.40 to 4.20 μm)
m: 71.7%), except that matte coated paper was obtained in the same manner as in Example 1. [Example 3] 60 parts of heavy calcium carbonate (FMT-90, volume distribution particle size: 0.40 to 4.20 µm: 71.7%) as a pigment contained in the coating liquid,
Brazilian kaolin (Rocacapim, Capim DG, volume distribution particle size 0.40 to 4.20 μm: 71.7%) 40
Part of a pigment (volume distribution particle size: 0.40 to 4.20 μm)
m: 71.7%), except that matte coated paper was obtained in the same manner as in Example 1. [Example 4] 50 parts of heavy calcium carbonate (FMT-90, volume distribution particle size: 0.40 to 4.20 µm: 71.7%) as a pigment contained in the coating liquid,
Second-class kaolin (manufactured by Drive Lunch Kaolin Co., Ltd., DB coat, volume distribution particle size: 0.40 to 4.20 μm: 61.8)
%) Pigment (volume distribution particle size: 0.40-4.
20 μm: 66.8%) to obtain a matte coated paper in the same manner as in Example 1. Comparative Example 1 20 parts of heavy calcium carbonate (manufactured by Sankyo Milling Co., Ltd., Escalon 1500, volume distribution particle diameter 0.40 to 4.20 μm: 25.0%) as pigments contained in the coating liquid, kaolin from Brazil ( A pigment (volume distribution particle size: 0.40 to 4.20 μm: 80 parts) manufactured by Riocapim Co., Ltd., Capim DG, volume distribution particle size: 0.40 to 4.20 μm: 71.7%
62.4%) to obtain a coated paper for printing in the same manner as in Example 1. Comparative Example 2 A matte coated paper was obtained in the same manner as in Example 2 except that the base paper did not contain an ester compound of a polyhydric alcohol and a fatty acid. [Comparative Example 3] Base paper having a basis weight of 103 g / m ² containing 100 parts by weight of chemical pulp as paper pulp and 12 parts by weight of light calcium carbonate as a filler was mixed with heavy calcium carbonate (FMT-90, manufactured by Pfimatec Corporation). 20 parts by weight, 80 kaolin from Brazil (manufactured by Rio Capim, Capim DG volume distribution particle diameter 0.40 to 4.20 μm: 71.7%) 80 Parts by weight of pigment (volume distribution particle size: 0.40 to 4.20 μm)
m: 71.7%), 0.1 part by weight of sodium polyacrylate as a dispersant, 11 parts by weight of a carboxy-modified styrene-butadiene latex as a binder, 3 parts by weight of a phosphorylated starch, and further, water and 65 parts by weight. A coating solution adjusted to a concentration of 1% by weight was coated at a coating amount of 14 g / m
So that ² performs the double-side coated at a coverage rate of 800 m / min blade coater, to obtain a matte coated paper. Comparative Example 4 A matte coated paper was obtained in the same manner as in Example 2 except that the basis weight of the base paper was 40 g / m ² and the coating amount was 12 g / m ² per one side.

In the matte coated paper manufactured under the above conditions, the basis weight, density, tear length in the papermaking direction, and Young's modulus in the papermaking direction were measured, and the product of the four was calculated. In addition, the coatability of the base paper with the paint, the glossiness of blank paper, the glossiness of printing, and the unevenness of gloss in the image area were evaluated. Further, evaluation of ease of page turning and evaluation of workability in a printing press when binding the same paper into a booklet were performed. The results are shown in Table 1.

[Table 1]

As is clear from Table 1, the pigment particles in the coating layer contained 65% in the range of 0.4 to 4.2 μm on a volume basis.
It has the particle size distribution included above, and the value of the product of the basis weight, density, Young's modulus in the papermaking direction, and tear length in the papermaking direction of the coated paper is 1.0 × 10 ²¹ g ² · N. / M ⁶ or more 4.0 × 10 ²¹
If it is within the range of g ² · N / m ⁶ or less, it is easy to turn pages because of its excellent flexibility, it is bulky, it has excellent workability of the printing press, and the glossiness of blank paper and the printing glossiness of the image area are high. ,
Further, it is clear that the coated paper for printing has little fine unevenness of gloss in the image area and good workability in a printing machine.

[0042]

Industrial Applicability According to the present invention, despite being bulky (low density), excellent in flexibility, and low in glossiness of white paper, the printing gloss of the image area is high, and the minute gloss unevenness of the image area is small. And a coated paper for printing having good workability in a printing press can be obtained.

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Takehide Kasahara 5-2-1-1, Oji, Kita-ku, Tokyo Nippon Paper Industries Co., Ltd. (72) Inventor Hirokazu Morii 5-2-1-1, Oji, Kita-ku, Tokyo No. Nippon Paper Industries Co., Ltd. (72) Inventor Hideki Fujiwara 5-21-1, Oji, Kita-ku, Tokyo Nippon Paper Industries Co., Ltd. F-term (reference) 4L055 AC05 AG12 AG27 AG34 AG48 AG63 AG71 AG76 AG89 AG97 AH02 AH33 AH37 AH50 AJ04 BE08 BE09 EA07 EA08 EA16 FA12 FA16 GA19

Claims (2)

[Claims] 1. A matte coated paper provided with a coating layer comprising a pigment and an adhesive on a base paper, wherein the pigment contains 65% or more of pigment in a range of 0.4 to 4.2 μm on a volume basis. It has a diameter distribution, and the product of the basis weight, density, Young's modulus in the papermaking direction, and tear length in the papermaking direction of the coated paper is 1.0 × 10 ²¹ g.
Matt coated paper characterized in that it is not less than ² · N / m ^{6 and not} more than 4.0 × 10 ²¹ g ² · N / m ⁶ . 2. 0.4 to 4.2 on a volume basis as pigments.
The matte coated paper according to claim 1, wherein kaolin having a particle size distribution of 65% or more in the range of μm is contained in an amount of 20 parts by weight or more per 100 parts by weight of the pigment.