JP2007303048A - Matte coated paper for printing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a matte coated printing paper having low white paper glossiness, resistant to rub staining, having excellent ink build-up property in printing and exhibiting excellent printability. <P>SOLUTION: The matte coated printing paper has one or two pigment coating layers composed mainly of a pigment and an adhesive on at least one surface of a stock paper and has a 75° white paper glossiness of ≤50% measured in conformity to ISO 8254-1 (1999). The pigment coating layer has a surface layer obtained by coating the pigment coating layer with an aqueous composition composed mainly of organic particles having an average particle diameter of 7-30 μm and an adhesive and containing 5-50 pts.mass of the adhesive based on 100 pts.mass of the solid content of the organic particle, and drying the applied aqueous composition. The average number of the organic particles in the surface layer is 0.7-8.0 per 100×100 μm of one surface of the surface layer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a matte coated paper for printing, and in particular, a matte coated paper for printing that is less likely to cause so-called scumming stains due to rubbing between the printed surface and the blank surface after printing, and its It relates to a manufacturing method.

  A matte coated paper is a coated paper that intentionally lowers the surface gloss of a white paper and brings out a refined and deep tone as a printed matter to give a high-class feeling. Such matte coated paper is widely used in high-quality art printing, high-quality posters, catalogs, calendars and the like. In general, matte coated paper is manufactured in two ways. One of them is a pigment having a coarse average particle diameter (usually an average particle diameter) compared to a pigment (usually a fine particle type having an average particle diameter of 0.1 to 2 μm) used for ordinary high gloss coated paper. The coating liquid containing 0.4 to 10 μm coarse grain type) is coated on a base paper and dried to produce a product as it is, or by performing a mild calendering process. One is using a roughened calender roll on the surface of the pigment coating layer that has been coated smoothly, and transferring the rough surface of the micron unit of the roll onto the surface of the coating layer to finish the mat and producing a product. Is the method.

  The matte coated paper produced in this way has practical problems due to its uneven surface. As a particularly big problem, in the post process after printing such as the printing process, the bookbinding process, or the conveying process, the ink of the printing part is transferred to the white paper part by friction between the printing part and the white paper part. “Cosmetic dirt” can be mentioned. In a printed publication, when the above-mentioned smudge stains occur, the appearance of printing deteriorates and the product value is lowered. When the stains are remarkable, a huge loss is incurred as a user complaint.

  There are two main causes for the occurrence of this smudge. One of them is derived from the structural specificity of the pigment coating layer of the matte coated paper. As described above, the matte coated paper is blended with a pigment having a coarse particle diameter. Concavities and convexities are formed on the surface of the coating layer, but the irregularities on the surface of the coating layer are large, and the calcium carbonate pigment forming the irregularities is rough and hard, so the ink film on the white paper portion and the printing portion is in contact. In this case, the hard convex portion of the white paper scrapes off the ink in the printing portion. The other is that the set-off and drying of the printed ink is slow, the bookbinding process and transport are performed before the ink film is completely polymerized and dried, and the blank part and the printed part come into contact with each other. Is transferred and dirty. Therefore, in order to solve the scumming stain on the matte coated paper for printing, it is possible to suppress the ink scraping of the printing part due to the unevenness of the white paper part and to promote the polymerization drying of the ink, and to form a strong ink film. It is necessary to form quickly.

  Conventionally, in order to solve such scumming stains, as the printing ink, a wear-resistant ink in which a friction-resistant compound mainly composed of wax or the like is added to the ink has been adopted, and the printed surface and the white surface are whitened. Measures such as reducing friction with the paper surface are taken. However, improving the printing ink alone does not provide the effect of reducing the smudge stain, and changing to a printing ink for these special applications leads to a decrease in productivity and an increased work load for the printer. Currently, there are many cases that are not adopted.

  On the other hand, various methods have been proposed as means for reducing scumming stains with coated paper. For example, as a means to refrain from blending calcium carbonate, which is the main cause of cosmetic stains, at least one pigment selected from kaolin, delaminated kaolin, and talc having an average particle size of 1.5 μm or more as a pigment is used. A method of blending 40% by weight or more with respect to the pigment (see Patent Document 1), calendered matte coated paper for printing, containing at least 90 parts by weight of kaolin as a pigment for forming a coating layer, A method of setting the average particle size of 5 to 15 parts by weight of kaolin to 1.5 μm or more (refer to Patent Document 2), 60 to 90% by weight of kaolin and 100% by weight of pigment component and adhesive component As a method, a coating solution containing a styrene / butadiene copolymer latex having a specific particle size is coated, dried, and calendered (see Patent Document 3). Proposed. However, in the matte coated paper, the method of increasing the amount of kaolin instead of calcium carbonate reduces cosmetic stains, but the increase in kaolin increases the white paper gloss and reduces the original texture of the matte coated paper. In addition, the whiteness is lowered and the printing appearance is deteriorated.

  Further, as a technique not involving an increase in the amount of kaolin as described above for reducing the amount of stains on the surface, a method in which a specific amount of polytetrafluoroethylene resin particles having a specific average particle diameter is contained in the pigment coating layer (see Patent Document 4). And a method of containing a specific amount of a specific emulsion as an ink transfer inhibitor in the pigment coating layer (see Patent Document 5). However, the above-mentioned various methods of adding organic particles and a lubricant to the pigment coating layer are those in which an expensive component that acts to prevent the cosmetic stain is blended in the entire pigment coated layer, but the cosmetic stain is generated. Since the active ingredient cannot be localized on the surface of the coating layer, it has the disadvantage of being extremely uneconomical.

  On the other hand, a method of applying a specific emulsion, polyolefin resin particles, a release agent and a specific surfactant to the surface of the coating layer (see Patent Documents 6, 7, and 8), the surface in the pigment coating layer A method of containing a specific amount of starch particles coated with silicone (see Patent Document 9), a method of containing a specific average particle size of calcium carbonate and a fatty acid metal salt in a pigment coating layer (see Patent Document 10), and pigment coating A method of containing calcium carbonate and a wax component having a specific average particle size in the coating layer (see Patent Document 11) has been proposed, but at present, there is a demand for further improvements in improving cosmetic stains. is there.

JP-A-9-31892 Japanese Patent Laid-Open No. 9-273098 Japanese Patent Laid-Open No. 10-140498 JP-A-10-96192 Japanese Patent Laid-Open No. 06-158594 JP 09-031893 A JP 2001-254294 A JP 2004-211241 A JP-A-8-127996 JP 2001-81694 A Japanese Patent Laid-Open No. 10-280295

  In the present invention, after a pigment coating layer is formed, an aqueous composition mainly composed of organic particles having a specific average particle diameter and a specific amount of an adhesive is coated on the pigment coating layer and dried. In addition, by providing an average number of organic particles of 0.7 to 8.0 per 100 × 100 μm on one side of the surface layer, the glossiness of white paper is low, and smearing is unlikely to occur. An object of the present invention is to provide a matte coated paper for printing which is excellent in ink fillability and excellent in printability.

The inventors of the present invention have made extensive studies in order to obtain a matte coated paper for printing that has low white paper glossiness, excellent smearing and good ink inking during printing, and excellent printability. It came to solve.
That is, according to the present invention, at least one surface of a base paper is provided with one or two pigment coating layers mainly composed of a pigment and an adhesive, and measured at 75 degrees according to ISO 8254-1 (1999). A matte coated paper for printing having a gloss of 50% or less of blank paper, comprising organic particles having an average particle diameter of 7 to 30 μm and an adhesive as main components on the pigment coated layer, the organic A surface layer obtained by coating and drying an aqueous composition containing 5 to 50 parts by mass of an adhesive with respect to 100 parts by mass of the particle solid content is provided, and the number of organic particles in the surface layer is the surface layer. The average number is 0.7 to 8.0 per 100 × 100 μm on one side.
The organic particles are preferably spherical and dense at least one kind of organic synthetic resin particles selected from acrylic resin particles, styrene resin particles, and tetrafluoroethylene resin particles.
The organic particles are preferably starch particles, and the surface of the starch particles is more preferably siliconized.
The organic particles are preferably petroleum wax particles having a melting point of 65 ° C. or more and a penetration of 15 mm or less, and more preferably 90% by mass or more of the petroleum wax particles are n-paraffin wax.
The amount of the surfactant contained in the petroleum wax particles is preferably 11% by mass or less based on the total solid content of the petroleum wax particles.
The surface layer is preferably formed by a spray method.
The coating amount of the surface layer after drying is preferably 0.01 to 0.3 g / m ² per side.
In the matte coated paper for printing provided with two pigment coated layers, the average particle diameter in the X-ray transmission particle size distribution measurement of all kinds of pigments in the pigment coated layer in contact with the base paper is 0.1 respectively. It is in the range of -1.3 μm, and the adhesive is 10 to 20 parts by mass with respect to 100 parts by mass of the pigment, and among the adhesives, the water-soluble adhesive is 4 parts by mass or less with respect to 100 parts by mass of the pigment. It is preferable to make it contain.
In the matte coated paper for printing provided with two pigment coated layers, it is preferable that 1-30% by mass is satin white in the total solid content of the pigment in the pigment coated layer in contact with the base paper.

  The matte coated paper for printing according to the present invention has low white paper glossiness, is less likely to cause scumming stains, has excellent ink fillability during printing, and has excellent printability.

Hereinafter, the contents of the present invention will be described in detail.
In order to obtain a matte coated paper for printing having a low blank paper glossiness, low smearing, excellent ink inking during printing, and excellent printability, at least one side of the base paper is used. In addition, one or two or more pigment coating layers mainly composed of a pigment and an adhesive are provided, and the 75 ° white paper gloss measured in accordance with ISO 8254-1 (1999) is 50% or less. A matte coated paper for printing, the organic particle having an average particle diameter of 7 to 30 μm and an adhesive as main components on the pigment coated layer, and 100 parts by mass of the organic particle solid content Then, a surface layer obtained by coating and drying an aqueous composition containing 5 to 50 parts by mass of an adhesive is provided, and the average number of organic particles in the surface layer is 0 per 100 × 100 μm on one side of the surface layer. .7 to 8.0 found to be achieved by did.

  Furthermore, in order to accelerate the polymerization drying of the ink and to form a strong ink film quickly, in the two pigment coating layers, the pigment coating layer (undercoat coating layer) in contact with the base paper is used as the ink drying acceleration layer. And found that is effective.

  The organic particles are spherical and solid, at least one organic synthetic resin particle selected from acrylic resin particles, styrene resin particles, and tetrafluoroethylene resin particles, starch particles, melting point 65 ° C. or higher, and Examples include petroleum wax particles having a penetration of 15 mm or less.

  In the organic synthetic resin particles, it is necessary to maintain the spherical shape even when subjected to heat treatment such as drying, and resin particles that are not easily thermally deformed are preferable, acrylic resin particles, styrene resin particles, and It is selected from tetrafluoroethylene resin particles.

  About the starch particle, it is necessary to maintain the particle shape without gelatinizing in the aqueous composition. For this reason, specifically, in the aqueous composition having a pH of 2 to 11 and a temperature of 5 to 50 ° C. Processed starch that does not gelatinize even when the starch particles are dispersed is preferred, and starch that is less gelatinized by crosslinking between starch molecules with a crosslinking agent such as formaldehyde, epichlorohydrin, or succinic acid as necessary is particularly preferred.

  Examples of the processed starch include wheat starch, rice starch, potato starch, corn starch, tapioca starch, sweet potato starch, taro starch, and the like. Since such a particle size of 7 to 30 μm is necessary, the starch types (classification by raw materials) used in the present invention include corn starch, wheat starch, Sweet potato starch is preferable, and among them, corn starch and wheat starch, which are relatively inexpensive and have a relatively small particle size, are particularly preferable. Rice starch and taro starch are not preferred because the starch has a small particle size, and potato starch has a large starch particle size, both of which may be out of the range of the starch particles described above.

  Moreover, about the said processed starch, in order to reduce frictional resistance and to further reduce a cosmetic stain | pollution | contamination, it is especially preferable to use the starch particle which surface-treated silicone.

  The petroleum wax particles preferably have a spherical shape and a non-hollow (solid) shape in order to suppress contact between the unevenness of the blank paper portion and the ink of the printing portion to reduce the smudge. If the particle shape of the petroleum wax is spherical and non-hollow (solid), the particles are uniform and do not collapse, so there is a possibility that the contact between the white paper portion and the ink in the printing portion can be sufficiently suppressed. is there.

  Further, the petroleum wax particles need to maintain the spherical shape even when subjected to heat treatment such as drying in the production of matte coated paper. Therefore, the melting point of the petroleum wax particles is preferably 65 ° C. or higher, and particularly preferably 72 ° C. or higher. When the temperature is 65 ° C. or higher, the petroleum wax particles are not softened and deformed by heat drying or the like in the manufacture of coated paper, and therefore, there is a possibility that the spherical shape necessary for acting as a spacer can be maintained.

  Further, the inventors have found that a specific petroleum wax has a specific effect of transferring the wax component from the surface layer of the coated paper to the printed ink film layer and improving the strength of the ink film. In view of the effect, it is particularly preferable that 90% by mass or more of the wax component is the n-paraffin wax as the petroleum wax particles. In general, petroleum waxes (paraffins) are roughly classified into n-paraffins having a linear hydrocarbon chain, isoparaffins having a branched chain, and cycloparaffins having a cyclic chain. When branched isoparaffins or cyclic cycloparaffins are mixed in the n-paraffin and the purity of the n-paraffin is low, the crystallinity when the paraffin is solidified (crystallized) becomes low, and the wax becomes soft. If the purity of the n-paraffin in the shape is 90% by mass or more, the wax crystallinity is high and the wax does not become too soft, so that the wax is transferred from the surface layer of the coated paper to the printed ink film. In this case, the strength of the ink film can be improved.

  As described above, the phenomenon in which the strength of the ink film printed on the surface of the coated paper by the wax is improved, particularly in the case of petroleum wax having specific physical properties, and the precise expression mechanism is Although it is unclear, as a result of an experimental investigation using a combination of coated papers with different waxes, the ink solvent (mainly petroleum solvent) contained in the printed ink film layer is The petroleum wax present on the surface of the coating layer is dissolved when it is absorbed by the layer and dried, but the dissolved wax is transferred to the ink film layer, and the wax is re-solidified in the ink film, so that the ink film This is considered to improve the strength of the ink film, thereby improving the slip property of the ink film.

  The wax is generally incorporated into the aqueous composition as an aqueous dispersion (emulsion) emulsified and dispersed using a surfactant. The amount of the surfactant when emulsifying and dispersing the petroleum wax particles is as follows. Is preferably 11% by mass or less, particularly preferably 10.5% by mass or less, based on the total solid content of petroleum wax. If the amount of the surfactant is 11% by mass or less, the petroleum wax melting point drop does not occur, and the familiarity between the wax and the ink solvent is not hindered, and the surfactant acts as an impurity of the wax to produce a wax crystal. There is no risk of reducing the properties and hardness.

  Further, the surfactant in the case of emulsifying and dispersing the petroleum wax particles is preferably a nonionic surfactant. By using a nonionic surfactant, a wax and an ink solvent (oil-based surfactant) are used. This does not hinder the familiarity and solubility with the solvent), and as a result, there is no risk of preventing the wax from transferring to the ink film.

  In addition, the organic particles used in the present invention have an average particle size (average particle size measured by a laser diffraction method) in order to reduce contact stains by suppressing contact between the unevenness of the blank paper portion and the ink of the printing portion. It is preferably in the range of 7-30 μm, particularly preferably in the range of 10-20 μm. When the average particle size is less than 7 μm, the particles are too small to prevent contact between the white paper portion and the ink in the printing portion, resulting in scumming stains. When the average particle size exceeds 30 μm, the particles are too large during printing. This is not preferable because the contact between the printing plate or the blanket and the paper is hindered, and problems such as poor ink deposition properties occur.

  In the present invention, an aqueous composition mainly composed of organic particles and an adhesive is used as a material for forming the surface layer. The adhesive is used in an amount of 5 to 50 masses per 100 mass parts of the organic particle solid content. It is preferable to mix part, and it is particularly preferable to mix 10 to 30 parts by mass. When the blending amount of the adhesive is less than 5 parts by mass, not only the adhesion force to the organic particles is insufficient, the organic particles may be peeled off from the surface layer, but also the particles are peeled off on the printing press. In such a case, there is a problem that particles are accumulated on a printing plate or a blanket, resulting in a problem such as contamination, or a problem that piling occurs during printing. Further, when the blending amount of the adhesive exceeds 50 parts by mass, the adhesive strength is sufficient and the organic particles are not peeled off, but an excessive amount of the adhesive is voids in the pigment coating layer of the coated paper. This is not preferable because it may obstruct the water absorption and ink drying properties required for coated paper for printing.

  In the present invention, the type of adhesive used in combination with the organic particles is not particularly limited, and examples thereof include proteins such as casein and soybean protein, styrene-butadiene copolymer, and methyl methacrylate-butadiene copolymer. Conjugated diene polymer latex, acrylic polymer latex, vinyl polymer latex such as vinyl polymer such as ethylene-vinyl acetate copolymer, or these various polymers containing functional groups such as carboxyl groups Depending on the body, functional group-modified alkali-soluble or alkali-insoluble polymer latex, polyvinyl alcohol, olefin-maleic anhydride resin, melamine resin and other synthetic resin adhesives, positive starch, oxidized starch, esterification Starches such as starch, carboxymethylcellulose, hydroxymethyl Cellulose derivatives such as cellulose or the like, an adhesive known as a general coated paper can be used alone or in combination.

  In the present invention, an aqueous composition mainly composed of organic particles and an adhesive that is coated and dried on a pigment coating layer of a coated paper in the present invention has a blue or purple color as long as the effects of the present invention are not impaired. System dyes and colored pigments, fluorescent dyes, thickeners, water retention agents, antioxidants, anti-aging agents, conductive treatment agents, antifoaming agents, UV absorbers, dispersants, pH adjusters, mold release agents, water resistance Various auxiliary agents such as an agent, a water repellent, and a wetting agent can be appropriately blended.

  In the present invention, the number of organic particles in the surface layer is in the range of 0.7 to 8.0 on average per 100 × 100 μm on one side of the coated paper, and in the range of 2.0 to 7.0. More preferred. Regarding the number of the organic particles, the surface layer was magnified 500 times with an electron microscope, photographed, the number of organic particles present in the surface layer was measured, and the number of organic particles per 100 × 100 μm on one side of the surface layer was measured. The average number is calculated, but when the average number is less than 0.7, it is impossible to prevent contact between the white paper portion and the ink in the printing portion as a spacer, and the effect of improving the stain stain is small. If the average number exceeds 8.0, the contact between the white paper portion and the ink in the printing portion can be sufficiently suppressed to reduce the smudge. However, in printing, the printing plate, blanket and paper This is not preferable because the contact of the ink is disturbed, and problems such as poor ink depositability occur.

Examples of the method for adjusting the number of organic particles present in the surface layer to 0.7 to 8.0 include coating amount after drying the surface layer and blending of an aqueous composition forming the surface layer. For example, the coating amount after drying is preferably in the range of 0.01 to 0.3 g / m ² per side, particularly preferably in the range of 0.05 to 0.2 g / m ² .

  In addition, in order to form a surface layer in the present invention, a method of coating an aqueous composition mainly composed of organic particles and an adhesive is generally used in the trailing, flexible, and roll industries. Applications, fountain applications, short dwell and other bevel and vent type blade coaters, air knife coaters, bar coaters, rod blade coaters, champ flex coaters, gate roll coaters, gravure coaters, curtain coaters, die coaters, spray coaters, etc. A coating apparatus can be used as appropriate, but a spray coating method is preferred in order to stably coat a small amount of organic particles without scraping the organic particles onto the pigment coating layer of the coated paper.

  Examples of the spray-type coating device described above include a nozzle-type spray device and a rotor dampening coating device that are generally used. Among these, the types of spray nozzles in the nozzle spray device include an empty conical nozzle that sprays in an annular shape, a full conical nozzle that sprays in a circular shape, a full pyramid that sprays in a square shape, a full nozzle and a fan Type nozzles, etc., so that the aqueous composition containing organic synthetic resin particles is sprayed uniformly in the width direction of the coated paper, the nozzle diameter, the number of nozzles, the nozzle arrangement pattern, the number of nozzle arrangements, or The spraying distance, the spraying pressure, the spraying angle, the concentration of the spraying liquid, the viscosity and the like can be appropriately adjusted and used. Moreover, about the method of atomizing the aqueous composition containing an organic synthetic resin particle in a nozzle type spraying apparatus, two types, a one-fluid system or a two-fluid system, can be selected and used. Among these, the one-fluid spraying method applies a direct pressure to the liquid to be sprayed using compressed air or pressurized steam and sprays mist droplets from the nozzle, or nozzles from fine holes opened on the side of the nozzle near the jet outlet This is a system in which air is sucked into the mist and jetted. In addition, the two-fluid spray method is an internal mixing type that mixes and atomizes compressed air or pressurized vapor liquid inside the nozzle, and mixes and atomizes mixed liquid that sprays compressed air or pressurized vapor outside the nozzle. Examples include an external mixing type that collides with each other and atomized atomized droplets that collide with each other to further homogenize and atomize the atomized droplets. In addition, the rotor dampening coating device is a device that sends out the liquid to be sprayed onto a disk that rotates at high speed and atomizes the liquid by the centrifugal force of the disk, and controls the particle size of the droplets by changing the rotational speed of the disk. The amount of spray liquid (application amount) is controlled by changing the amount of liquid delivered onto the disk.

  In the present invention, in order to spray an extremely small amount of an aqueous composition containing organic particles uniformly on the surface of the pigment-coated paper, the atomized particle size of the atomized aqueous composition is as small as possible (liquid (Drop size: 30 μm or less). However, if the mist droplets become too fine, the mist droplets may be swept away by the rebound of the sprayed air or air accompanying the surface of the pigment coated paper, especially when the application speed to the coated paper is high. It becomes difficult to adhere to the surface of the paper. For this reason, in the spray application method, the spray distance, spray pressure, spray angle, and spray speed are added, and in the case of the two-fluid method, the mixing ratio of the aqueous composition for spraying and compressed air / pressurized steam, and the aqueous The concentration and viscosity of the composition can be adjusted as appropriate to adjust the particle size to suit the coating conditions. If the influence of the accompanying air is large during spraying, a suction device or an obstacle to remove the accompanying air can be used. A charged electrode (electrostatic spray) that improves the adhesion of mist to pigment coated paper by installing a plate (rectifying plate) and applying a high voltage of about 20000 V to the tip of the spray nozzle to charge the mist droplet particles. Method) may be added.

  Further, the mist droplets floating as mist without being applied to the pigment coated paper surface can be sucked and collected and sprayed again.

  About these spray application methods, an extremely small amount of spray liquid can be uniformly applied to the surface of the pigment coated paper while suppressing the spraying of the fog droplets, and the spray speed, the particle size of the fog, etc. can be adjusted. An easy rotor dampening application is preferred.

  In the present invention, the spraying of the aqueous composition containing organic particles on the surface of the pigment coating layer may be performed by spraying directly on the surface of the pigment coating layer using the coating device. Without spray application to the surface of the pigment coating layer, after spray application to the surface of another resin roll once, the aqueous composition may be indirectly applied by bringing the resin roll into contact with the surface of the pigment coating layer. it can.

  In the present invention, the timing of applying the aqueous composition containing the organic particles to the surface of the pigment coating layer is any manufacturing process as long as the pigment coating layer coating liquid is coated on the coating base paper. However, the pigment coating layer may be wet or dry. Also, the method of drying the aqueous composition coated on the pigment coating layer is not particularly limited. For example, various methods such as steam drying, gas heater drying, electric heater drying, infrared heater drying and the like are used. can do.

In the present invention, the coated paper having a surface layer obtained by applying and drying an aqueous composition containing organic particles on the pigment coating layer is based on ISO 8254-1 (1999). It is not particularly limited as long as the measured 75 degree white paper gloss is 50% or less matte coated paper for printing. The aqueous coating liquid for pigment coating layer is generally composed mainly of pigment and adhesive. to prepare a solid content of about 20 to 70 wt%, per side 5 to 25 g / ^{m 2} by dry weight on the base paper, coated as more preferably about 7~20g / ^{m 2,} dried I just need it. Further, the layer structure of the pigment coating layer is not particularly limited as long as one layer or two layers are formed on one side.

  Further, in the present invention, in order to reduce the smear, the undercoating coating contacting the base paper when two pigment coating layers are provided in order to accelerate the polymerization drying of the ink and form a strong ink film quickly. The layer is preferably an ink drying acceleration layer.

  In this case, with respect to the pigment used for the undercoat coating layer, it is preferable that all types of pigments have an average particle diameter in the X-ray transmission type particle size distribution measurement of 0.1 to 1.3 μm, respectively. The particle diameter is more preferably in the range of 0.3 to 1.0 μm. This is because the size of the voids in the pigment coating layer (void diameter) and the amount of voids (void volume) have a large effect on the ink drying property, and the ink drying property is increased by increasing the number of small voids in the coating layer. Furthermore, the particle size of the pigment blended in the coating layer has a great influence on the formation of the coating layer void, but the pigment particle size used in the undercoat coating layer exceeds 1.3 μm. Is not preferable because it facilitates ink drying and makes it difficult to sufficiently reduce the coating layer gap. Moreover, when the particle diameter of the pigment used for the undercoat coating layer is less than 0.1 μm, the coating layer gap for promoting the ink drying property can be made sufficiently small. The required amount of adhesive for the required strength development is increased, which is not preferable because it is uneconomical.

  In the present invention, as the pigment of the undercoat pigment coating layer, 1 to 30% by mass of satin white having an average particle diameter in the range of 0.1 to 1.3 μm is contained in the total solid content of the pigment. The content is preferably 3 to 20% by mass. This is the fact that satin white is an alumina complex pigment having a fine acicular crystal shape, but when fine acicular crystal satin white is blended with the pigment coating layer, many voids are formed in the coating layer. It can be formed, and the ink drying property of the pigment coating layer can be promoted by this gap. For this reason, when the content of satin white in the pigment coating layer is less than 1% by mass, sufficient voids cannot be formed in the pigment coating layer, and the ink drying property is not accelerated, which is not preferable. In addition, when the content of satin white in the pigment coating layer exceeds 30% by mass, it is possible to sufficiently form voids in the pigment coating layer to increase the ink drying property. This is not preferable because the required amount of adhesive for increasing the strength required is increased, which is uneconomical.

  Further, in the present invention, the pigment other than the specified satin white used for the undercoat coating layer may be in the range of the average particle diameter specified as described above, and the pigment type is not particularly limited, For example, calcium carbonate, kaolin, calcined kaolin, structural kaolin, deramikaolin, talc, calcium sulfate, barium sulfate, aluminum hydroxide, titanium dioxide, zinc oxide, alumina, magnesium carbonate, magnesium oxide, silica, magnesium aluminosilicate, silicic acid Inorganic pigments such as calcium bentonite, zeolite, sericite, and smectite, organic pigments such as solid, hollow, and through-hole type plastic pigments and binder pigments are used. One of these is possible Rui can be appropriately selected and used or two or more kinds.

  In the present invention, it is important that the adhesive in the undercoat layer is 10 to 20 parts by mass with respect to 100 parts by mass of the total pigment, and the adhesive content in the undercoat layer is based on the total pigment. It is particularly preferable to contain 10 to 18% by mass, and the water-soluble adhesive in the adhesive is preferably contained so as to be 4 parts by mass or less with respect to 100 parts by mass of the pigment. It is particularly preferable that the amount be 2 parts by mass or less. The water-soluble adhesive preferably contains a small amount of about 0.1 parts by mass for the purpose of thickening and water retention. This is because an adhesive is contained in the coating layer in order to develop the printing strength required as a coated paper for printing, but the adhesive content is less than 10% by mass with respect to the total pigment. Is not preferable because it is difficult to give sufficient printed strength to the coated paper. Further, when the content of the adhesive exceeds 20% by mass with respect to the total pigment, the adhesive fills the gaps in the undercoat coating layer to promote ink drying, and the ink drying property of the coated paper. Is not preferable because it becomes too slow.

  In addition, water-soluble adhesives tend to fill the gaps in the coating layer compared to dispersed adhesives, and have a great influence on the ink drying properties of the coated paper. For this reason, when the content of the water-soluble adhesive in the undercoat layer exceeds 4 parts by mass with respect to the total pigment, the ink drying property of the undercoat layer is remarkably deteriorated (delayed), which is not preferable.

  The adhesive to be contained in the undercoat coating layer is not particularly limited, and adhesives used in the ordinary coated paper field, for example, water-soluble adhesives such as oxidized starch, esterified starch, and cold water soluble Various starches such as starch, proteins such as casein, soy protein, synthetic protein, cellulose derivatives such as carboxymethylcellulose and methylcellulose, polyvinyl alcohol and modified products thereof, and styrene-butadiene Polymers, conjugated diene polymer latex such as methyl methacrylate-butadiene copolymer, acrylic polymer latex, vinyl polymer latex such as ethylene-vinyl acetate copolymer, etc. can be used. Depending on the situation, one or more of these may be selected as appropriate Rukoto can.

  In addition, the aqueous coating solution for the undercoat coating layer includes a blue or purple dye, a colored pigment, a fluorescent dye, a thickener, a water retention agent, an antioxidant, as long as the effects of the present invention are not hindered. Various auxiliaries such as an anti-aging agent, a conductive treatment agent, an antifoaming agent, an ultraviolet absorber, a dispersant, a pH adjuster, a mold release agent, a water-resistant agent, and a water repellent can be appropriately blended.

  The coating device for each pigment coating solution including the aqueous coating solution for the undercoat pigment coating layer in the present invention is not particularly limited, and is generally used in the industry. Roll application, fountain application, short dwell and other bevel type and vent type blade coaters, air knife coaters, bar coaters, rod blade coaters, champ flex coaters, gate roll coaters, gravure coaters, curtain coaters, die coaters, spray coaters, etc. These coating devices can be used as appropriate. Of course, these devices may be on-machine or off-machine. Moreover, it does not specifically limit as a method of drying a wet coating layer, For example, various systems, such as vapor | steam drying, gas heater drying, electric heater drying, and infrared heater drying, are employable.

  Moreover, in this invention, 75 degree whiteness measured based on ISO8254-1 (1999) can be made into 50% or less as an overcoat pigment coating layer in case a pigment coating layer is one layer or two layers. As long as it is a thing, it will not specifically limit, The pigment generally used for the coated paper for printing, an adhesive agent, and various adjuvants can be selected suitably, and can be used.

  The pigment in the topcoat pigment coating layer is not particularly limited, and pigments used in the ordinary coated paper field, for example, inorganic pigments such as calcium carbonate, kaolin, calcined kaolin, structural kaolin, deramikaolin, Inorganic pigments such as talc, calcium sulfate, barium sulfate, aluminum hydroxide, satin white, titanium dioxide, zinc oxide, alumina, magnesium carbonate, magnesium oxide, silica, magnesium aluminosilicate, calcium silicate bentonite, zeolite, sericite, smectite In addition, as organic pigments, it is possible to use pigments used in the ordinary coated paper field, such as solid, hollow, and through-hole type plastic pigments, binder pigments, and the like. Alternatively, two or more types can be appropriately selected and used.

  The adhesive for the top coat pigment coating layer is not particularly limited, and adhesives used in the ordinary coated paper field, such as water-soluble adhesives such as oxidized starch, esterified starch, and cold water-soluble starch. Styrene-butadiene copolymer of various starches of the above, proteins such as casein, soy protein, synthetic proteins, cellulose derivatives such as carboxymethylcellulose and methylcellulose, polyvinyl alcohol and modified products thereof, and as dispersion adhesives It is possible to use conjugated diene polymer latex such as methyl methacrylate-butadiene copolymer, acrylic polymer latex, vinyl polymer latex such as ethylene-vinyl acetate copolymer, etc. From these, one or more types can be selected and used as appropriate. Kill.

  In addition, the aqueous coating solution for the top coating layer, in a range that does not interfere with the effect of the present invention, blue or purple dyes and colored pigments, fluorescent dyes, thickeners, water retention agents, antioxidants, Various auxiliaries such as an anti-aging agent, a conductive treatment agent, an antifoaming agent, an ultraviolet absorber, a dispersant, a pH adjuster, a mold release agent, a water-resistant agent, and a water repellent can be appropriately blended.

  The coating device for each pigment coating solution including the aqueous coating solution for the undercoat pigment coating layer in the present invention is not particularly limited, and is generally used in the industry, trailing, flexible, Roll application, fountain application, short dwell and other bevel type and vent type blade coaters, air knife coaters, bar coaters, rod blade coaters, champ flex coaters, gate roll coaters, gravure coaters, curtain coaters, die coaters, spray coaters, etc. These coating devices can be used as appropriate. Of course, these devices may be on-machine or off-machine. Moreover, it does not specifically limit as a method of drying a wet coating layer, For example, various systems, such as vapor | steam drying, gas heater drying, electric heater drying, and infrared heater drying, are employable.

  In the matte coated paper for printing in the present invention, the pigment coated paper before applying the aqueous composition containing organic particles and the matte coating after applying the aqueous composition containing organic particles. For the paper, smoothing processing such as super calendering or brushing may be performed as necessary.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In addition, unless otherwise indicated, the part and% in an example show a mass part and the mass%, respectively. Moreover, the average particle diameter of the organic particles used in Examples and Comparative Examples and the pigment for coated paper, the melting point of petroleum wax particles, and the penetration were measured by the following methods.

-Average particle size of organic synthetic resin particles and starch particles Measure the particle size distribution of organic synthetic resin particles or starch particles using a laser diffraction particle size distribution analyzer (model name: SALD-2000, manufactured by Shimadzu Corporation) The average particle diameter corresponding to a cumulative mass of 50% was determined. The dispersion of the organic synthetic resin particles or starch particles used for the measurement was prepared by adding a sodium polyacrylate dispersant (trade name: Aron T50, manufactured by Toagosei Co., Ltd.) to the organic synthetic resin particles or starch particles. Add 0.5% and dilute the organic synthetic resin particles or starch particles so that the solid content concentration is 1%. Then, in the measurement, if necessary, organic synthesis to the concentration range measurable with the measuring device. The resin particle or starch particle dispersion was diluted before use.

-Using an average particle size analyzer of petroleum wax particles (trade name: LA-920, manufactured by HORIBA, Ltd.), the particle size distribution of various wax particles (emulsions) was measured, and the average corresponding to a cumulative mass of 50% The particle size was determined. In the measurement, the wax particles (emulsion) were diluted to a concentration range measurable with the measuring device as necessary.

-Melting | fusing point of petroleum wax particle The melting | fusing point of various wax particle | grains was measured according to JISK2235.3 using the wax melting | fusing point measuring device. Since the various wax particles are in a water-dispersed state (emulsion state), a wax sample is prepared by drying at 120 ° C. using a dryer to evaporate and remove moisture, and the wax sample is subjected to a temperature drop every 15 seconds. The instruction of the thermometer was read, and the temperature within a certain range (when the difference within 0.1 ° C. lasted 5 times) was defined as the melting point of the wax particles.

-Penetration of petroleum wax particles The penetration (hardness of wax) of various petroleum waxes was measured according to JIS K2254.4 using a penetration meter. Since various petroleum wax particles are in a water-dispersed state (emulsion state), a petroleum wax sample is prepared by drying at 120 ° C. using a dryer to remove water by evaporation, and a load of 0.98 N is applied to the petroleum wax sample. The depth (mm) of the needle that enters the wax at 25 ° C. for 5 seconds was defined as the penetration of the petroleum wax particles.

-Average particle diameter of pigment X-ray transmission type particle size distribution measuring device (model name: Cedygraph 5100, manufactured by Micromeritics) was used to measure the particle size distribution of pigments for coated paper by the precipitation method. The average particle size corresponding to 50% by mass was determined. In addition, the dispersion liquid of the pigment used for the measurement added a sodium polyacrylate dispersant (trade name: Aron T50, manufactured by Toa Gosei Co., Ltd.) 0.05% to the pigment, and the pigment solid content concentration was 50 to 70. % Of the slurry was prepared by using a 0.1% aqueous solution of a sodium pyrophosphate-based dispersant (Nancarin S1, manufactured by Rin Chemical Industry Co., Ltd.). The product was diluted to about 10%).

Example 1
・ Preparation of coating solution for undercoat pigment coating layer in contact with base paper Pigment slurry made of 100% heavy calcium carbonate (trade name: Hydrocurve 60, manufactured by Bihoku Flour & Chemical Co., Ltd.) with an average particle size of 1.3 μm as a pigment Then, 0.2 part of sodium polyacrylate (trade name: Aron T50, manufactured by Toa Gosei Co., Ltd.) is added as a dispersant to 100 parts of pigment, and dispersed in water using a Cowles disperser. % Pigment dispersion was prepared. 9 parts of oxidized starch (trade name: Oji Ace A, manufactured by Oji Cornstarch Co., Ltd.), styrene-butadiene copolymer latex (trade name: OJ1000, manufactured by JSR) as an adhesive with respect to 100 parts of pigment in this dispersion. 4 parts (all in terms of solid content) were blended, and auxiliary agents such as an antifoaming agent and a dye were added to finally prepare a coating solution having a solid content concentration of 57%.

・ Preparation of coating solution for topcoat pigment coating layer As pigment, 70 parts of heavy calcium carbonate (Hydrocurve-90, manufactured by Bihoku Flour Industries Co., Ltd.) and 30 parts of kaolin (HT, manufactured by Engelhard, USA) To the pigment slurry, 0.2 parts of sodium polyacrylate (trade name: Aron T50, supra) as a dispersant is added to 100 parts of the pigment, and dispersed in water using a Cowles disperser. A 70% pigment dispersion was prepared. 3 parts of oxidized starch (trade name: Oji Ace A, supra) and 7 parts of styrene-butadiene copolymer latex (trade name: OJ2000, manufactured by JSR) as an adhesive with respect to 100 parts of pigment in this dispersion. (Both in terms of solid content) were added, and auxiliary agents such as an antifoaming agent and a dye were added to finally prepare a coating solution having a solid content concentration of 62%.

-Preparation of pigment coated paper On a high-quality base paper (72.5 g / m < ² > tsubo) having a tenacity of 0.73 g / cm < ³ >, the above-mentioned coating liquid for undercoat pigment coating layer is dry weight per side Was coated on both sides using a blade coater and dried so as to be 9 g / m ² to provide an undercoat pigment coating layer. Next, the top coat pigment coating layer is coated on both sides using a blade coater and dried so that the dry weight per side is 9 g / m ² to provide a top coat pigment coating layer. A pigment-coated paper with a gloss of 31% was obtained.

Preparation of aqueous composition containing organic particles As organic particles, 100 parts of acrylic resin particles (trade name: MX-1000, manufactured by Soken Chemical Co., Ltd.) having an average particle diameter of 10 μm are used as a dispersing agent. Sodium polyacrylate (trade name: Aron T50, supra) 0.1 parts, polyvinyl alcohol (trade name: PVA105, manufactured by Kuraray Co., Ltd.) 30 parts as an adhesive, sulfosuccinate type anionic surfactant (product) Name: Sanmorin OT-70, manufactured by Sanyo Kasei Kogyo Co., Ltd.) 0.05%, and an auxiliary agent such as an antifoaming agent was added to finally prepare an aqueous composition having a solid content concentration of 1%.

・ Manufacture of matte coated paper for printing Rotor dampening device (model name: WEKO rotor dampening, manufactured by Nikka Co., Ltd.) as a coating device for the pigment coated paper with coating speed (line speed) of 100 m / min Is used to spray an aqueous composition containing organic particles having a solid content concentration of 1% at a spray amount of 400 g / min · m width on one side of the pigment-coated paper (4 g as a coating liquid amount). / m ² , 0.04 g / m ^{2 as} the absolute dry coating amount) and then drying to obtain a matte coated paper for printing having a white paper gloss of 28%.

Example 2
In the preparation of the aqueous composition containing the organic particles of Example 1, a matte coated paper for printing was prepared in the same manner as in Example 1 except that the final solid content concentration of the aqueous composition was 6%. Obtained.

Example 3
In the application of the aqueous composition containing the organic particles of Example 2 to the surface of the pigment coating layer, a two-fluid spray spray device (model name: BIMV11004 type, manufactured by Kirinoikeuchi Co., Ltd.) as the coating device, and the spray spray device Example 2 except that an electrostatic spray spray device in which an elliptical electrode (both power supply and electrode manufactured by Kasuga Denki Co., Ltd.) through a 20000 volt high-voltage DC power source was installed at a position about 2 cm from the nozzle tip of the nozzle was used. Thus, a matte coated paper for printing was obtained. The coating liquid amount was 4 g / m ² .

Example 4
In the preparation of the aqueous composition containing the organic particles of Example 2, Example was used except that 100 parts of acrylic resin particles (trade name: MX-3000, manufactured by Soken Chemical Co., Ltd.) having an average particle size of 30 μm were used as the organic particles. In the same manner as in Example 2, a matte coated paper for printing was obtained.

Example 5
In the preparation of the aqueous composition containing the organic particles of Example 1, except that 100 parts of polytetrafluoroethylene resin particles (trade name: Flou300, manufactured by MicroPowder) having an average particle diameter of 7 μm were used as the organic particles. In the same manner as in Example 1, a matte coated paper for printing was obtained.

Example 6
In preparation of the aqueous composition containing the organic particles of Example 2, except that 100 parts of polystyrene resin particles (trade name: S2584 (A) -7, manufactured by JSR) having an average particle diameter of 10 μm were used as the organic particles. In the same manner as in Example 2, a matte coated paper for printing was obtained.

Example 7
Matte coating for printing in the same manner as in Example 2 except that 10 parts of polyvinyl alcohol (trade name: PVA105, supra) was added as an adhesive in the preparation of the aqueous composition containing the organic particles of Example 2. A paper was obtained.

Example 8
Matte coating for printing in the same manner as in Example 2 except that 50 parts of polyvinyl alcohol (trade name: PVA105, supra) was blended as an adhesive in the preparation of the aqueous composition containing the organic particles of Example 2. A paper was obtained.

Example 9
In the preparation of the coating liquid for the undercoat pigment coating layer in contact with the base paper of Example 2, heavy calcium carbonate having an average particle diameter of 1.3 μm as a pigment (trade name: Hydrocurve 60, supra) 90%, average particle diameter 10% of 0.5 μm satin white (trade name: SWBL, manufactured by Shiroishi Kogyo Co., Ltd.), 2 parts of oxidized starch (trade name: Oji Ace A, supra) as an adhesive, and styrene-butadiene copolymer For printing in the same manner as in Example 2 except that 10 parts of latex (trade name: OJ1000, supra) (all in terms of solid content) was used, and finally the coating liquid had a solid content concentration of 59%. A matte coated paper was obtained.

Example 10
Preparation of aqueous composition containing wax particles Petroleum wax having an average particle diameter of 10 μm (trade name: N481-0705-3, melting point: 72 ° C., penetration: 9 mm, n-paraffin content: 90% or more, average Particle size: 10 μm, surfactant amount (based on 100 parts by weight of wax component): 10.5 parts, manufactured by Chukyo Oil & Fats Co., Ltd.) 100 parts by weight of the total solid content of wax, polyacrylic acid as a dispersant Sodium (trade name: Aron T50, supra) 0.1 parts, polyvinyl alcohol (trade name: PVA105, supra) 30 parts as an adhesive, sulfosuccinate type anionic surfactant (trade name: Sanmorin OT) as a wetting agent -70, supra) 0.05% was added, and an auxiliary agent such as an antifoaming agent was added to finally prepare an aqueous composition having a solid content concentration of 1%.

-Preparation of matte coated paper for printing Example 1 and the preparation of the aqueous composition containing the organic particles of Example 1 except that the aqueous composition was changed to the aqueous composition containing the wax particles described above. Similarly, a matte coated paper for printing was obtained.

Example 11
A matte coated paper for printing was obtained in the same manner as in Example 10 except that the final solid content concentration of the aqueous composition was 6% in the preparation of the aqueous composition of Example 10.

Example 12
In application of the aqueous composition of Example 11 to the surface of the pigment coating layer, a two-fluid spray spray device (model name: BIMV11004 type, supra) as a coating device, and a position about 2 cm from the nozzle tip of the spray spray device In addition, the gloss for printing was the same as in Example 11 except that an electrostatic spray spraying device having an elliptical electrode (power source and electrode both made by Kasuga Denki Co., Ltd., mentioned above) through a 20000 volt high-voltage DC power source was used. An erased coated paper was obtained. The coating liquid amount was 4 g / m ² .

Example 13
In the preparation of the aqueous composition containing the petroleum wax particles of Example 11, petroleum wax having an average particle diameter of 13.5 μm (trade name: N481-1022-2, melting point: 72 ° C., penetration: 9 mm, n-paraffin content: 90% or more, average particle size: 13.5 μm, surfactant amount (with respect to 100 parts by mass of wax component): 10.5 parts, 100 parts by Chukyo Yushi Co., Ltd. Matte coated paper for printing was obtained in the same manner as in Example 11 except that the final solid content concentration of the aqueous composition containing the wax particles was 6%.

Example 14
Preparation of aqueous composition containing starch particles Corn starch starch particles having an average particle size of 12 μm (trade name: Oji Ace C, average particle size: 12.0 μm, manufactured by Oji Corn Starch Co., Ltd.) To 100 parts, 0.1 parts of sodium polyacrylate (trade name: Aron T50, supra) as a dispersant, 30 parts of polyvinyl alcohol (trade name: PVA105, supra) as an adhesive, and sulfosuccin as a wetting agent Nate type anionic surfactant (trade name: Sanmorin OT-70, supra) 0.05% is added, and an auxiliary agent such as an antifoaming agent is added, and finally an aqueous composition having a solid content concentration of 1%. Was prepared.

-Preparation of matte coated paper for printing Example 1 is the same as the preparation of the aqueous composition containing the organic particles of Example 1, except that the aqueous composition was changed to the aqueous composition containing the above-mentioned starch particles. Similarly, a matte coated paper for printing was obtained.

Example 15
Matte coated paper for printing was obtained in the same manner as in Example 14 except that the final solid concentration of the aqueous composition was 6% in the preparation of the aqueous composition of Example 14.

Example 16
In application of the aqueous composition of Example 15 to the surface of the pigment coating layer, a two-fluid spray spray device (model name: BIMV11004 type, supra) as a coating device, and a position about 2 cm from the nozzle tip of the spray spray device In addition, the gloss for printing was the same as in Example 15 except that an electrostatic spray spraying device having an elliptical electrode (power source and electrode both made by Kasuga Denki Co., Ltd., mentioned above) through a 20,000-volt high-voltage DC power source was used. An erased coated paper was obtained.

Example 17
In the preparation of the aqueous composition containing the starch particles of Example 14, wheat starch particles having an average particle size of 19.8 μm as the starch particles (trade name: Glyco B, average particle size: 19.8 μm, manufactured by Glico Nutrition Foods, Inc.) A matte coated paper for printing was obtained in the same manner as in Example 14 except that 100 parts were used and the final solid content concentration of the aqueous composition containing the starch particles was 6%.

Example 18
In the preparation of the aqueous composition containing the starch particles of Example 14, silicone surface-treated starch particles having an average particle size of 22.3 μm (trade name: NIKKARYCO-SL, average particle size: 22.3 μm, manufactured by Nikka Co., Ltd.) ) A matte coated paper for printing was obtained in the same manner as in Example 14 except that 100 parts were used and the final solid content concentration of the aqueous composition containing the starch particles was 6%.

Comparative Example 1
For application to the pigment coating layer of the aqueous composition containing the organic particles of Example 1, except that the aqueous composition was not applied to the pigment-coated paper. A matte coated paper was obtained.

Comparative Example 2
In the preparation of the aqueous composition containing the organic particles of Example 1, 100 parts of acrylic resin particles (trade name: MX-500, manufactured by Soken Chemical Co., Ltd.) having an average particle diameter of 5 μm were used as the organic particles. A matte coated paper for printing was obtained in the same manner as in Example 1 except that the final solid content concentration was 1%.

Comparative Example 3
In the preparation of the aqueous composition containing the starch particles of Example 14, 100 parts of rice starch particles having an average particle size of 5 μm (trade name: Kaminshin Powder, average particle size: 5.0 μm, manufactured by Maehara Flour Mills Co., Ltd.) as starch particles In addition, a matte coated paper for printing was obtained in the same manner as in Example 14 except that the final solid content concentration of the aqueous composition containing the starch particles was 1%.

Comparative Example 4
In the preparation of the aqueous composition containing the starch particles of Example 14, 100 parts of silicone surface-treated starch particles having an average particle diameter of 47 μm (trade name: NIKKARYCO-L, average particle diameter: 47 μm, manufactured by Nikka) as starch particles. A matte coated paper for printing was obtained in the same manner as in Example 14 except that the final solid content concentration of the aqueous composition containing the starch particles was 6%.

Comparative Example 5
In the preparation of the aqueous composition containing the petroleum wax particles of Example 10, petroleum wax having an average particle diameter of 5 μm (trade name: N900, melting point: 72 ° C., penetration: 9 mm, n-paraffin content: 90% or more, average particle size: 5 μm, surfactant amount (with respect to 100 parts by mass of wax component): 10.5 parts, 100 parts by weight of Chukyo Yushi Co., Ltd., and an aqueous composition containing the wax particles A matte coated paper for printing was obtained in the same manner as in Example 1 except that the final solid content concentration of the product was 1%.

Comparative Example 6
In the preparation of the aqueous composition containing the organic particles of Example 5, a matte coated paper for printing was prepared in the same manner as in Example 5 except that the final solid content concentration of the aqueous composition was 6%. Obtained.

Comparative Example 7
Matte coating for printing in the same manner as in Example 5 except that in the preparation of the aqueous composition containing the organic particles of Example 5, the final solid content concentration of the aqueous composition was 0.1%. I got paper.

Comparative Example 8
Matte coated paper for printing as in Example 10, except that in the preparation of the aqueous composition containing the petroleum wax particles of Example 10, the final solid content concentration of the aqueous composition was 12%. Got.

Comparative Example 9
In the preparation of the aqueous composition containing petroleum wax particles of Example 10, the matte coating for printing was performed in the same manner as in Example 10 except that the final solid content concentration of the aqueous composition was 0.1%. A paper was obtained.

Comparative Example 10
In the preparation of the aqueous composition containing the starch particles of Example 14, a matte coated paper for printing was prepared in the same manner as in Example 14 except that the final solid content concentration of the aqueous composition was 12%. Obtained.

Comparative Example 11
Matte coating for printing in the same manner as in Example 14 except that in the preparation of the aqueous composition containing the starch particles of Example 14, the final solid content concentration of the aqueous composition was 0.1%. I got paper.

Comparative Example 12
Matte coating for printing in the same manner as in Example 1 except that 3 parts of polyvinyl alcohol (trade name: PVA105, supra) was blended as an adhesive in the preparation of the aqueous composition containing the organic particles of Example 2. A paper was obtained.

  The matte coated paper for printing thus obtained was evaluated as follows, and the results obtained are summarized in Tables 1 and 2. Note that the measurement and evaluation of the matte coated paper for printing in the present invention were performed in an environment of 23 ° C. and 50 RH% unless otherwise specified.

・ The number of organic particles in the surface layer The surface layer of the matte coated paper for printing is observed with an electron microscope, a magnified observation photograph of 500 times is taken, and the entire area of the SEM photograph (500 times photograph dimensions: length 89 mm × width 118 mm) After counting the number of organic particles present in the sample, the average number of organic particles present per actual surface layer (100 μm × 100 μm) was calculated.

・ Glossiness of white paper The gloss of each matte coated paper for printing is measured using a gloss meter (model name: GM-26D, manufactured by Murakami Color Research Laboratory Co., Ltd.) in accordance with ISO 8254-1 (1999). The 75 ° gloss was measured.

・ Cosmetic stain suitability Using an RI type printing tester (Made Seisakusho), offset printing ink (trade name: Values-G black S type, Dainippon Ink Chemical Co., Ltd.) 0.4 cc gloss for each printing The entire surface of the eraser coated paper was subjected to solid printing, and the printed matter was left to dry for 24 hours and 72 hours. Then, using a friction fastness tester (manufactured by Toyo Seiki Seisakusho Co., Ltd.), the printed surface of each coated paper and the white coated layer surface are overlapped and subjected to one-way friction with a load of 4.9 N. According to the following standard, the density of the ink stain (= scratch stain) transferred to the coating layer surface was evaluated by visual observation.
A: There is no transfer of ink.
○: There is a slight ink transfer, but there is no practical problem.
(Triangle | delta): There are many transfer of ink and there exists a problem in practical use.
X: Ink transfer is very much.

・ Printability (ink fillability and print smoothness)
Using an RI printing tester, 0.1 cc of offset printing ink (trade name: Values-G ink S type, supra) was used to perform solid printing on each matte coated paper for printing and transfer. The ink density (ink fillability) and the transfer uniformity of the ink (printing smoothness) were evaluated by visual observation according to the following criteria.
A: Printability is particularly excellent.
○: Printability is excellent.
Δ: Printability is slightly inferior, which is a problem in practical use.
X: Printability is inferior.

・ Surface strength 4-color offset sheet-fed printing press (model name: Speedmaster SM-102-6-P-LX-UV / IR, Heidelberg) and offset printing ink (trade names: Values-G, ink, indigo) , Red, yellow each S type, made by Dainippon Ink Chemical Co., Ltd.), and printing machine blanket stains (due to insufficient surface strength) at the end of printing 2000 parts of matte coated paper for printing (Piling) was evaluated by visual observation according to the following criteria.
○: No problem in practical use.
X: Inferior and practically problematic.

  As is apparent from Table 1, in Examples 1 to 18, organic particles having a specified average particle diameter range were used, and the number of organic particles per 100 × 100 μm on one side of the surface layer was set to a specified range. By setting the blending amount of the adhesive used together with the specified range, low glossiness of white paper and high surface stain reduction effect and high surface strength can be achieved without impairing printability such as ink fillability. Is done. Further, in Example 9, by promoting the ink drying property of the undercoat pigment coating layer by blending with satin white or the like, the drying of the ink film progresses and the ink film becomes stronger, and the effect of reducing the scum stain is exhibited in a shorter time. Has been able to.

  On the other hand, as is clear from Table 2, when the surface layer containing organic particles is not provided as in Comparative Example 1, the average particle diameter of the organic particles is defined as in Comparative Examples 2, 3, and 5. If the number is smaller than the specified range, or if the number of organic particles per 100 × 100 μm per side of the surface layer is less than the specified range as in Comparative Examples 7, 9, and 11, the cosmetic stain is sufficiently reduced. On the other hand, when the average particle diameter of the organic particles is larger than the specified range as in Comparative Example 4, or the number of the organic particles is more than the specified range as in Comparative Examples 6, 8, and 10. In some cases, even though the smudge can be reduced, it is not possible to maintain good printability such as ink fillability. Moreover, when the compounding quantity of the adhesive used together with the organic particles is too small as in Comparative Example 12, it is not possible to obtain a surface strength at a level necessary for a coated paper for printing.

  As described above, the method of the present invention is excellent in printability such as print finish without impairing the original appearance of the matte coated paper for printing, and has been a problem in the bookbinding process of the coated paper for printing. Dirt can be solved.

Claims (11)

  One or two pigment coating layers mainly composed of a pigment and an adhesive are provided on at least one side of the base paper, and the 75 ° white paper glossiness measured according to ISO 8254-1 (1999) is 50. % Matte coated paper for printing, the organic particle having an average particle diameter of 7 to 30 μm and an adhesive as main components on the pigment coating layer, and the organic particle solid content of 100 mass A surface layer obtained by coating and drying an aqueous composition containing 5 to 50 parts by weight of an adhesive is provided on the part, and the number of organic particles in the surface layer is 100 × 100 μm on one side of the surface layer. Matt coated paper for printing, characterized in that the average is 0.7 to 8.0 per sheet.   2. The printing according to claim 1, wherein the organic particles are at least one of spherical and solid organic synthetic resin particles selected from acrylic resin particles, styrene resin particles, and tetrafluoroethylene resin particles. Matte coated paper.   The matte coated paper for printing according to claim 1, wherein the organic particles are starch particles.   The matte coated paper for printing according to claim 3, wherein the surface of the starch particles is treated with silicone.   The matte coated paper for printing according to claim 1, wherein the organic particles are petroleum wax particles having a melting point of 65 ° C. or more and a penetration of 15 mm or less.   The matte coated paper for printing according to claim 5, wherein 90% by mass or more of the petroleum wax particles is n-paraffin wax.   The matte coated paper for printing according to claim 5 or 6, wherein the amount of the surfactant contained in the petroleum wax particles is 11% by mass or less based on the total solid content of the petroleum wax particles.   The matte coated paper for printing according to any one of claims 1 to 7, wherein the surface layer is formed by a spray method. The matte coated paper for printing according to any one of claims 1 to 8, wherein the coating amount of the surface layer after drying is 0.01 to 0.3 g / m ² per side.   In the matte coated paper for printing provided with two pigment coated layers, the average particle diameter in the X-ray transmission particle size distribution measurement of all kinds of pigments in the pigment coated layer in contact with the base paper is 0.1 respectively. It is in the range of -1.3 μm, and the adhesive is 10 to 20 parts by mass relative to 100 parts by mass of the pigment, and among the adhesives, the water-soluble adhesive is 4 parts by mass or less with respect to 100 parts by mass of the pigment The matte coated paper for printing as described in any one of Claim 1 to 9 contained so that it might become.   The matte coated paper for printing according to claim 10, wherein in the pigment coated layer in contact with the base paper, 1 to 30% by mass is satin white in the total solid content of the pigment.