JP5682460B2 - Method for producing coated paper for printing - Google Patents

Description

  The present invention relates to a method for producing a coated paper for printing.

  In general, coated paper for printing is manufactured by applying a coating liquid mainly composed of pigment and adhesive onto a base paper and drying it. Depending on the amount of coating and the method of finishing the coated paper, cast coated paper is used. , Art paper, coated paper, finely coated paper, etc. These coated papers are subjected to multicolor printing or single color printing, and are widely used as commercial printed materials such as leaflets, brochures and posters, or as publications such as books and magazines. In recent years, with the progress of visualization and colorization of printed matter, there has been an increasing demand for higher quality coated paper for printing. Printing of white paper quality such as white paper glossiness, smoothness and whiteness, and printing smoothness etc. Quality such as finishing is regarded as important. In addition, because there is a demand for low-cost, high-quality print finishes, especially for commercial prints, the manufacture of coated paper that is superior in quality, stable in quality, and can be manufactured more efficiently There is a need for a method.

  Paper machines that make base paper used for coated paper are becoming wider and faster for the purpose of saving labor and reducing manufacturing costs. Many modifications to the top type former have been made. By installing the top wire on the wire of the long net former and making it on-top type, the dewatering ability at the wire part that occurs with the increase in speed is insufficient, the formation deteriorates due to the disturbance of the raw material surface, the single-sided dewatering It became possible to suppress an increase in the difference in characteristics between the front and back of the paper due to reinforcement. However, when the papermaking speed of the paper machine exceeds 1200 m / min, even on-top type formers begin to deteriorate due to increased turbulence of the raw material surface at the initial long mesh section, causing a reduction in product quality. Therefore, it is difficult to increase the speed further.

  For this reason, a gap-type former that has been developed to enable high-speed operation is a gap-type former that immediately sandwiches the raw material from the head box with two wires. In the gap former, since the raw material that has left the head box is immediately sandwiched between two wires, it becomes possible to compensate for the shortage of dewatering capability associated with the increase in speed. In addition, the free surface of the raw material on the wire can be eliminated, and the dewatering pressure applied to the raw material between the wires can be optimized, so that the base paper is also improved, especially in the newsprint manufacturing field. Former was introduced and now it is a major equipment specification.

  On the other hand, in the coating process, the blade coating method is the mainstream as a coating method for obtaining high-quality coated paper. The blade coating method is suitable for high-speed coating, has a small quality difference in the width direction, and has high smoothness on the surface of the coated paper, as compared with other coating methods. However, the pigment coating layer formed by the blade coating method has a feature that the coating layer thickness varies greatly because a coating layer having a smooth surface is formed on the uneven base paper. For this reason, in the place where the coating layer thickness is thick, the amount of adhesive per unit area of the coated paper is relatively larger than in other places.

  As the adhesive in the pigment coating layer, various starches and latexes are mainly used. Among these, water-soluble starch contributes to improving the stiffness of coated paper and improves operability during blade coating. It is one of the adhesives preferably used to contribute to the above. However, when starch is used, starch molecules also move with moisture evaporation in the drying process of the pigment coating layer in the wet state, and the occurrence of binder migration localized on the coated paper surface becomes significant.

  Due to the difference in wet coating layer thickness, the amount of adhesive contained varies depending on the location of the paper, or as a result of not performing proper drying, the binder migration locally increased the adhesive on the coated paper surface. In this case, the ink acceptability at the time of multicolor printing becomes non-uniform, which causes a printing trouble called uneven unevenness, which causes a problem because the printing quality is deteriorated. Therefore, the drying process in the production process of coated paper not only dries and solidifies the wet pigment coating layer, but also greatly affects the print quality of the coated paper. Control is a challenge. In addition, binder migration is slight when various starches are not contained as an adhesive for the pigment coating layer, or even if it is contained, the effect of the drying process on the print quality of the coated paper is not noticeable. I can't.

As a conventional drying method for coated paper, a hot-air drying method using infrared air or a high-temperature air generated by heat exchange of pressurized steam or gas combustion is known.
The hot air drying method has the advantage that the drying conditions can be finely controlled because a large number of nozzles are arranged in the paper flow direction. However, the heat conduction is only from the surface and the drying efficiency is inferior. When the wet pigment coating layer is dried after the work is performed, a large number of hot air drying units must be arranged, which increases the installation area and the cost of introducing the equipment.
On the other hand, the infrared drying method uses the temperature rise phenomenon of the object due to infrared absorption, and has the advantage of excellent drying efficiency per unit length in the paper flow direction of the dryer, but runs continuously. Since the substrate is held only by the paper rolls inside and outside the dryer, the running stability is inferior, and further, fine control of the drying conditions is difficult due to its high drying ability.

  Several proposals have been made to improve the printing quality of coated paper for printing. A method in which an aqueous coating liquid containing a specific pigment is preliminarily dried with infrared rays (see Patent Documents 1 and 2), a method in which a specific auxiliary agent is used in combination and preliminarily dried with infrared rays (Patent Documents) 3) is the same in that the infrared drying method is used as a preliminary drying device. Here, since the infrared drying method is mainly intended to increase the temperature by absorbing infrared rays, when infrared drying is performed before the hot air drying step, the aqueous phase temperature in the wet coating layer containing starch or the like is increased. In general, since the viscosity of a starch solution decreases when the temperature is high, it is considered that the starch in the aqueous phase becomes more easily moved with the evaporation of moisture than the case of a low temperature due to the increase of the aqueous phase temperature. . With the recent increase in coating speed, the effect of suppressing binder migration is not sufficient only by using the infrared drying method as a preliminary drying device. In addition, at the present time when the coating speed is further increased, it is difficult to produce coated paper efficiently only by preliminary drying using infrared rays.

  On the other hand, a composite drying method combining an infrared drying method and a hot air drying method has also been proposed as a new drying device (see Patent Document 4 and Non-Patent Document 1). In this method, it is described that the infrared drying method has a high drying capacity and the hot air drying method has a stable sheet running property. However, it is disclosed that a narrow width coating up to a paper width of 5.4 m is disclosed. It is only an example of time, and there is no description about paint formulation.

  As described above, there is still room for improvement as a production method for efficiently producing coated paper for printing excellent in print quality.

JP-A-6-108396 JP 7-34397 A JP-A-6-108395 Japanese Patent No. 4190630

Paper PA Technical Paper Vol. 56, No. 2, High Power Density Non-contact Dryer “Uni Dryer”, Solaronics IRT G. Kennard et al. February 2002

  The present invention is a method for producing a coated paper, by adopting a specific drying method for a specific coating liquid, excellent in ink drying at the time of printing, without occurrence of uneven unevenness, and further in the width direction. An object of the present invention is to provide a production method capable of efficiently producing coated paper having no variation in print quality.

The present invention includes the following inventions.
(1) A method for producing a coated paper for printing having a pigment coating layer, wherein the base paper constituting the coated paper is obtained by paper making with a gap former type paper machine, and constitutes the coated paper At least one pigment coating layer is provided by coating on a base material containing 1 part by mass or more of starch (solid content) with respect to 100 parts by mass of all pigments and running at 1000 m / min or more. And then drying in a drying step, and at least a part of the drying step is dried in a composite drying unit that combines an infrared drying method and a hot air drying method.
(2) A method for producing a coated paper having two or more pigment coated layers on one side, wherein the base paper constituting the coated paper is obtained by making paper with a gap former type paper machine, and the coated paper The outermost pigment coating layer constituting the coating contains 1 part by mass or more of starch (solid content) with respect to 100 parts by mass of the total pigment, and is applied by coating on a substrate that runs at 1000 m / min or more. Then, it is preferably dried in a drying step, and at least a part of the drying step is preferably dried in a combined drying unit that combines an infrared drying method and a hot air drying method.
(3) The infrared drying method is a gas combustion infrared drying method, and the hot air drying method is preferably an air floating hot air drying method.
(4) In the said drying process, it is preferable to dry with a composite-type drying unit previously, and also to dry with a hot air drying system.
(5) The coating width on which the pigment coating layer is formed is preferably 5.5 m or more.
(6) It is preferable that the pigment coating layer is provided by a blade coating method.
(7) It is preferable that the pressurization dehydration amount of the aqueous coating liquid which forms the outermost pigment coating layer measured on the following conditions is 20-120 g / m < ² >.
(Measurement condition)
Pressure dehydration amount when using a membrane filter with a pore size of 0.1 μm under the conditions of a pressure of 100 kPa and a pressurization time of 30 seconds with a Kaltec Scientific AA-GWR water retention meter.

  According to the present invention, it is possible to efficiently produce coated paper having no unevenness in the printing process, excellent in ink drying property, and particularly having no variation in printing quality in the width direction, and having stable quality.

The present invention is described in detail below.
Non-wood pulp such as kenaf, bagasse, bamboo, and cotton can be used as the cellulose fiber that is the main component of the base paper used in the present invention, but typically pulp made from wood is used. The raw material of the wood pulp may be either hardwood or softwood, and as a cooking method for obtaining pulp from the raw material, a known cooking method such as kraft cooking, polysulfide cooking, soda cooking, alkali sulfite cooking, etc. should be used. However, cooking methods such as the Lo-solids method, the Compact cooking method, the Kobudomari cooking method, etc., which are the cooking methods in which the cooking liquor is added in portions, have a small amount of energy used during cooking, and the bleaching properties of the pulp to be produced are Since it has the effect of being good, it is preferably used.

  It is preferable that the unbleached pulp obtained by the above is delignified by a known alkaline oxygen bleaching method after washing, rough selection and selection steps. As the alkaline oxygen bleaching method that can be used in the present invention, a known medium concentration method or high concentration method can be applied as it is, but a medium concentration method that is currently used at a pulp concentration of 8 to 15% is preferred. .

  In the alkali oxygen bleaching method using the medium concentration method, caustic soda or oxidized kraft white liquor can be used as the alkali. As the oxygen gas, oxygen from a cryogenic separation method, PSA (Pressure Swing Adsorption) Oxygen, oxygen from VSA (Vacuum Swing Adsorption), etc. can be used. The oxygen gas and alkali are added to a medium-concentration pulp slurry in a medium-concentration mixer, and after sufficiently mixed, sent to a reaction tower capable of holding a mixture of pulp, oxygen and alkali for a certain period of time under pressure, Delignified.

  The oxygen gas addition rate is 0.5 to 3% by mass per mass of dry pulp, the alkali addition rate is 0.5 to 4% by mass, the reaction temperature is 80 to 120 ° C., the reaction time is 15 to 100 minutes, and the pulp concentration Is 8 to 15%, and other known conditions can be applied. In the present invention, in the alkaline oxygen bleaching step, it is a preferred embodiment that the alkali oxygen bleaching is continuously performed a plurality of times and delignification proceeds as much as possible.

  The pulp that has been subjected to alkaline oxygen bleaching is then sent to a washing step. After washing, the pulp is sent to a multistage bleaching process.

  In the multi-stage bleaching step for obtaining the bleached pulp used in the present invention, a known bleaching step can be used as appropriate, but from the viewpoint of efforts for environmental problems in recent years, it is preferable to use an ozone bleaching step. If necessary, chlorine dioxide and other bleaching chemicals can be used in combination. As the bleaching stage that can be used in the multi-stage bleaching step of the present invention, a known bleaching stage can be used in addition to the ozone bleaching stage that is preferably used. The pulp after multistage bleaching is sent to a beating process or a papermaking process.

  In addition, for the above pulp, mechanical pulp such as ground pulp, pressurized ground wood pulp, refiner ground wood pulp, thermomechanical pulp, deinked waste paper pulp, waste paper, etc., as long as the desired effect of the present invention is not hindered. Can be used mixed. Furthermore, pulp obtained by making a pulp slurry with a paper machine and making it into a sheet in a wet state or a dry state can be used again to obtain a pulp slurry.

  The pulp constituting the base paper is subjected to a beating process, and then sent to a paper machine as a paper stock which is a slurry-like pulp aqueous dispersion. For this paper material, fillers, internally added sizing agents, anionic, nonionic, cationic or amphoteric retention improvers, drainage improvers, paper strength enhancers, etc. It can be added as necessary. As for the papermaking conditions of the base paper, any system such as acidic papermaking, neutral papermaking, and weak alkali papermaking may be used.

  In the present invention, the filler added to the stock and used to form the base paper includes, for example, heavy calcium carbonate, light calcium carbonate, calcium sulfite, gypsum, talc, clay, calcined kaolin, white carbon, amorphous Inorganic pigments such as silica, delaminated kaolin, diatomaceous earth, magnesium carbonate, titanium dioxide, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, zinc hydroxide, organic pigments such as urea / formalin resin fine particles, micro hollow particles, etc. The filler contained in waste paper, waste paper, etc. can also be reused. Two or more fillers can be used in combination. The amount of filler added is generally such that the paper (base paper) ash content is in the range of 3 to 30% by mass, preferably 5 to 20% by mass.

  Specific examples of the internally added sizing agent used in the present invention include, for example, sizing agents such as alkyl ketene dimer, alkenyl succinic anhydride, styrene-acrylic, higher fatty acid, petroleum resin, and rosin. Is mentioned. Specific examples of yield improvers, filter pigment improvers, and paper strength enhancers include, for example, polyvalent metal compounds such as aluminum (specifically, sulfate bands, aluminum chloride, sodium aluminate, basic aluminum compounds). Etc.), various starches, polyacrylamide, urea resin, polyamide polyamine resin, polyethyleneimine, polyamine, polyvinyl alcohol, polyethylene oxide and the like. Moreover, it is also possible to use a bulking agent and a softening agent having a function of inhibiting the binding between pulp fibers as long as the effects of the present invention are not hindered. Specific examples of bulking agents and softeners include, for example, ester compounds of polyhydric alcohols and fatty acids, polyoxyalkylene compounds of polyhydric alcohols and fatty acid ester compounds, fatty acid polyamidoamines, polyhydric alcohol surfactants, An ionic surfactant etc. can be illustrated. The amount of the bulking agent and the softening agent is generally about 0.05 to 2.0% by mass relative to the pulp in terms of dry weight.

  Forming a sheet-like base paper from a stock containing additives and chemicals necessary for a slurry-like pulp water dispersion. As a form of base paper, the operability and the quality of the resulting base paper Use a good gap former format. The gap former type paper machine includes a blade forming type, a roll forming type, and a composite type of these, and any of them can be used.

  In addition, as the paper discharge direction of the gap former mainly composed of pulp and filler, there are a vertical discharge type that discharges substantially vertically upward, and an angle formed between the horizontal direction toward the downstream side of the paper machine and the paper discharge direction. There is an inclined discharge type of 30 to 80 °, either of which can be adopted. The base paper may be single-layer paper or multilayer paper.

  In press parts that are used in combination with a gap former or the like and squeeze the wet stock formed in the former part to increase the solids concentration, the known press types such as the trinip press, trinip press + 4P However, in order to improve the squeezing performance and improve the operability in an operating state exceeding 1200 m / min, it is preferable to use a shoe press, In order to reduce, it is preferable to use a tandem shoe press type using two shoe presses. Further, in order to improve the smoothness of the base paper, it is possible to adopt a format in which 3P is further added after the tandem shoe press.

The basis weight of the base paper to be made is not particularly limited, but is preferably in the range of 30 to 250 g / m ² in order to improve the base paper formation. The base paper that has passed through the press part is dried by a dryer to obtain a desired moisture, and then sent to a size press process as necessary.

In the size press process, starch and polyvinyl alcohol are used for the purpose of suppressing the penetration of the coating liquid into the base paper in order to effectively enhance the surface strength of the resulting coated paper and to provide the effect of providing a pigment coating layer. An aqueous solution or an emulsion type polymer containing a natural or synthetic water-soluble polymer such as polyacrylamide is coated on the base paper. In the size press process, the amount of coating when performing a so-called clear size that does not contain a pigment, considering the manifestation of the effect of the size press and the avoidance of operability deterioration due to an increase in the drying load, preferably 0.1 to 3.0 g / ^{m 2} as coated amount, 0.2 to 2.0 g / ^{m 2} is more preferable. The coating amount when performing so-called pigment size pressing, which contains a pigment in the size pressing step, is preferably 0.5 to 6.0 g / m ² from the same viewpoint as the solid content coating amount per one side of the base paper. 0.8 to 4.0 g / m ² is more preferable.

  As a coating device in the size press process, the coating liquid in the size press process is a clear size press that does not contain a pigment or a pigment size press that contains a pigment. In the case of operation, it is preferable to use a film transfer type roll coating apparatus in order to avoid a decrease in production efficiency due to troubles such as paper breakage and to ensure coating uniformity. A film transfer type roll coating device uses a blade or a rod as a measuring device to measure the desired amount of coating liquid on the surface of the roll before contacting the base paper, and apply this coating liquid to the base paper. A size press, that is, coating is carried out by contacting and transferring. In consideration of the durability of the device, the metering device is more preferably a rod metering size press using a rod.

  After passing through the size press process, the coating layer is dried with a dryer and sent to the pigment coating layer coating process, but the pigment coating layer coating is performed before the size pressing process or after the drying after the size pressing process is completed. Before the construction process, if necessary, the machine calender by the combination of metal roll / metal roll, or the combination of the metal roll / elastic roll, and the smoothing finish processing by the soft calender etc. which heated the metal roll may be applied. it can.

  The coating apparatus for forming the pigment coating layer is not particularly limited. For example, a vent blade coater, a bevel blade coater, an air knife coater, a roll coater, a reverse roll coater, a bar coater, a curtain coater, and a slot die coater. An apparatus such as a gravure coater, a champlex coater, a brush coater, a two-roll or rod metalling or blade metalling type size press coater, a bill blade coater, a short dwell coater, a gate roll coater, or a spray coater is appropriately used. Among these, when the coating speed when forming the pigment coating layer on the base paper is 1000 m / min or more, considering the operability and productivity, and the quality of the resulting coated paper, a blade coater can be used as the coating device. Or a roll coater is preferable and a blade coater is most preferable.

  In the present invention, the pigment used in the pigment coating layer is not particularly limited, for example, ordinary kaolin, calcined kaolin, structured kaolin, engineered kaolin, various kaolins such as delaminated kaolin, Refined natural mineral pigments such as talc, heavy calcium carbonate (ground calcium carbonate), light calcium carbonate (synthetic calcium carbonate), composite synthetic pigments of calcium carbonate and other hydrophilic organic compounds, satin white, barium sulfate, sulfuric acid Zinc, titanium dioxide, silica, alumina, aluminum hydroxide, zinc oxide, magnesium carbonate, hollow or solid organic pigment plastic pigments, adhesive pigments, plastic beads, microcapsules, etc. that do not impair the effects of the present invention Can be mixed and used as appropriate That.

  Adhesives used in the coating layer include starch purified from natural plants, hydroxyethylated starch, oxidized starch, etherified starch, phosphate esterified starch, enzyme-modified starch, and cold water soluble obtained by flash drying them Various starches such as starch, starch derivatives such as carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, natural polysaccharides such as dextrin, mannan, chitosan, arabinogalactan, glycogen, inulin, pectin, hyaluronic acid and oligomers thereof Examples include modified products. Furthermore, natural polymers such as casein, gelatin, soybean protein, and collagen, and modified products thereof, and synthetic polymers and oligomers such as polylactic acid and peptides can be mentioned. In addition, copolymer latexes such as styrene butadiene, acrylic, polyvinyl acetate, ethylene vinyl acetate, polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl pyrrolidone, modified polyvinyl pyrrolidone, sodium polyacrylate, polyethylene oxide, polyacrylamide, urea Alternatively, water-soluble synthetic compounds such as melamine / formalin resin, polyethyleneimine, polyamide polyamine / epichlorohydrin, and the like can be given. One or more of these can be used. In addition, the use of a known natural or synthetic organic compound is not particularly limited.

  Further, as a thickener used in the coating liquid, cellulose derivatives such as methyl cellulose, carboxymethyl cellulose, hydroxymethyl cellulose, gums such as sodium alginate, xanthan gum, guar gum, water soluble polymers such as casein, sodium polyacrylate, Examples thereof include synthetic polymers such as polyacrylates and styrene maleic anhydride copolymers, and inorganic polymers such as silicates.

  In addition, if necessary, various commonly used assistants such as dispersants, wetting agents, fluidity modifiers, antifoaming agents, water resistance agents, printability improvers, preservatives, slime control agents, and coloring agents. Agents and those obtained by cationizing these various auxiliary agents are preferably used.

  The paint solid content concentration at the time of application of the aqueous coating liquid for forming the pigment coating layer is generally adjusted in the range of 50 to 75% by mass, and more preferably 60 to 72% by mass. In order to improve the quality of the obtained coated paper, the lower limit of the solid content concentration of the paint is preferably 62% or more, and more preferably 64% or more. In addition, the coating-material solid content concentration at the time of coating means the coating-solution solid content concentration at the time of actually contacting a base paper in a coating process. When the coating liquid adjusted to the prescribed concentration is applied on the base paper and then applied in a lightweight manner after the excess is scraped off, the paint after receiving the dehydrating action of the base paper is recovered. Since it is reused, the solid concentration increases compared to the concentration at the time of adjustment.

The pressure dehydration amount of the aqueous coating liquid for forming the pigment coating layer is not particularly limited, but a Kaltec Scientific AA-GWR water retention meter is used. The pressure pressure is 100 kPa and the pressure time is 30 seconds. It is preferable that the aqueous coating liquid is ²⁰ to 120 g / m ² as the amount of pressure dehydration when using a membrane filter having a pore diameter of 0.1 μm.

When the amount of pressure dehydration is large, the water retention of the paint is inferior, and when the paint comes into contact with the base paper, more water moves to the base paper and the adhesive component also moves, and the coating layer strength tends to be inferior. is there. Furthermore, in the drying process, water in the aqueous coating liquid easily moves, so that binder migration tends to occur in the direction of the coating layer surface, causing unevenness of the ink deposits and reducing ink drying properties. Adopting the drying method of the present invention makes it easy to suppress binder migration even when the water retention of the paint is inferior, making it difficult to cause uneven unevenness when printing coated paper, and good ink drying properties It can be. When the amount of pressure dehydration that is an index of water retention is large, the viscosity of the aqueous coating solution is low, and it may be difficult to obtain a desired coating amount, or the drying load in the drying process may increase. preferably 100 g / ^{m 2} or less as the upper limit of the amount of dehydration, 80 g / ^{m 2} or less is more preferable.
On the other hand, when the water retention is excellent and the pressure dehydration amount is less than 20 g / m ² , binder migration is less likely to occur, but the solid content concentration of the aqueous coating solution is too high, making it difficult to control the coating amount. Or, the drying efficiency may be significantly reduced during drying. For this reason, it is preferable that it is 25 g / m < ² > or more as a pressure dehydration amount used as a water retention index, and it is more preferable that it is 30 g / m < ² > or more.

The total coating amount of the pigment coating layer is about 3 to 40 g / m ² per side, preferably 5 to 30 g / w, considering the white paper quality, print quality, and coating / processing suitability of the resulting coated paper. It is regulated in m ² approximately. Among these, as a preferable range of the coating amount per one side in the outermost coating layer, the lower limit is 6 g / m ² or more, the upper limit is 20 g / m ² or less, and the more preferable range is 8 g / m ² as the lower limit. m ² or more and the upper limit is 16 g / m ² or less.

  The arrangement method of the coating apparatus may be an on-machine coater type arranged so that the process from the paper making process to the coating process is continuously performed, and coating with a size press after the paper making process and drying of the coating liquid. After the process, it may be of an off-machine coater type in which it is wound once with a winder and then unwound again from the unwinder and used for the pigment coating layer coating process including the outermost pigment coating layer. From the viewpoint of improving the production efficiency of coated paper, the on-machine coater type is preferred.

  In the present invention, in drying the pigment coating layer in a wet state, at least a part thereof is dried by a combined drying unit (hereinafter simply referred to as a combined drying unit) that combines an infrared drying method and a hot air drying method. It is characterized by.

  As an aqueous coating liquid for forming a pigment coating layer, a coating liquid containing 1 part by mass or more of starch (solid content) with respect to 100 parts by mass of the total pigment is coated on a base paper, and then a composite drying unit is used. By using and drying, the ink drying property at the time of printing coated paper is improved as compared with the case where it is not. The reason for this is not clear, but it is considered that the layer structure of the pigment coating layer becomes porous and excellent in the absorption of the vehicle in the ink by passing through the drying process by the composite drying unit. Incidentally, if the starch content in the pigment coating layer is less than 1 part by mass, the effect of improving the ink drying property due to drying in the composite drying unit is not seen. The upper limit of the starch content is not limited, but 10 parts or less is a preferable range in order to avoid a decrease in production efficiency due to a decrease in the concentration of the aqueous coating liquid, and from the balance between ink drying properties and other coated paper quality 1-8 parts by mass is a more preferred range, and 2-6 parts by mass is the most preferred range.

  In the case of printing coated paper with two or more pigment coating layers per side of the base paper, the composition of the outermost pigment coating layer greatly affects the print quality, so it is combined with the outermost pigment coating layer. It is more preferable to dry using a mold drying unit.

  The composite drying unit is characterized by having both an infrared drying method and a hot air drying method in one drying unit. The drying unit disclosed in Japanese Patent No. 4190630 is a typical example. As the infrared drying method, various methods such as an electric method and a gas combustion method can be used. The hot air drying method is a canvas support method in which hot air is discharged from only one side of the base paper via an air flotation nozzle and the opposite side is supported by a canvas, etc., hot air is blown out from both sides, and the running base paper is not contacted The air floating system supported by

Among these, from the viewpoint of improving the drying efficiency of the wet coating layer, it is preferable that the infrared drying method is a gas combustion infrared drying method, and from the viewpoint of running stability of the base paper, the hot air drying method is an air floating hot air. A drying method is preferred.
In addition, from the viewpoint of improving the drying efficiency of the wet coating layer, the gas drying infrared emitter group of the infrared drying method and the air flotation nozzle of the hot air drying method are alternately arranged in the composite drying unit. It is preferable that the infrared emitter group and the air flotation nozzle are arranged in at least two or more repeating units in one composite drying unit.
Furthermore, if the infrared emitter group and the air flotation nozzle are both arranged on the front and back sides of the substrate and the drying conditions on the front and back sides can be controlled independently, the wet state of the pigment coating layer in the wet state can be controlled. This is preferable because control becomes easy and curling control of the coated paper obtained becomes easy.

  As a method of drying the wet pigment coating layer coated on the base paper, at least part of the composite drying unit is used, and conventionally known and publicly used hot air drying, gas heater drying, high frequency drying, electric heater Various heat drying methods such as drying, infrared heater drying, laser drying, and electron beam drying may be used in combination.

  In particular, after drying the wet pigment coating layer in a composite drying unit, and further drying in a hot air drying system dryer, efficient drying can be achieved and drying in the previous composite drying unit. By changing the drying conditions of the subsequent hot air dryer according to the state, it is possible to effectively suppress the occurrence of uneven unevenness during printing due to binder migration, which is a preferred embodiment in the present invention.

Further, in the case of coated paper having two or more pigment coating layers per side of the base paper, after drying the wet pigment coating layer in a composite drying unit as the outermost pigment coating layer, It is preferable to perform drying with a drying dryer because blank gloss and printing gloss are improved as compared with the case of drying only with a composite drying unit. When drying with only the combined drying unit, if the drying strength becomes too strong, pores of about 5 to 10 μm that are thought to be caused by rapid vapor permeation are generated on the coated paper surface. These pores cannot be recognized visually, but reduce the gloss of white paper and printing. The drying conditions of the composite drying unit and the hot air dryer are set so that the number of pores is 200 or less, preferably 100 or less, more preferably 50 or less per 1 mm ^{2 of} coated paper. By adjusting, the glossiness of the blank paper and the printing gloss become better than when not. The number of the pores means an average number obtained by observing the surface of 10 mm ² coated paper with an electron microscope or an optical microscope and calculating the number per 1 mm ² .

  In the case of drying only with the conventional hot air drying method, when the width of the base paper to be coated is 5.5 m or more, the print quality is different between the edge and the center of the paper compared to the case where it is not. Likely to happen. The cause is not necessarily clear, but in hot air dryers, in principle, it is operated in a sealed state in order to improve drying efficiency. The air flow at the edge of the paper near the dryer wall and the air flow near the center It is thought that this is caused by the difference in moisture transfer rate and binder migration. In the drying method according to the present invention, the main process of drying is performed by the composite drying unit, and therefore, it is possible to effectively prevent the quality variation in the width direction. When the coating width to be applied is 5.5 m or more, the effect of preventing the quality fluctuation in the width direction is remarkable, and when the coating width is 7.5 m or more, the effect is particularly remarkable. The upper limit of the coating width is preferably 12 m or less in consideration of the ease of production of the coating machine and the drying device. In order to achieve both the production efficiency of the coated paper and the ease of production of the coating machine and the drying device, the coating width is particularly preferably 7.5 to 11 m.

  When the coating speed of the pigment coating layer is 1000 m / min or more, since it is necessary to dry in a short time, the drying equipment becomes enormous and a large installation space is required. Using the composite drying unit that combines the infrared drying method and the hot air drying method at least in part of the drying process of the present invention, the installation space and cost can be greatly reduced while maintaining excellent quality. . The above effects are exhibited when the coating speed is 1300 m / min or more, particularly 1500 m / min or more. The upper limit of the coating speed is not limited as long as there is no problem with the formation of the wet coating layer on the base paper, but currently the upper limit is about 2500 m / min.

  In the present invention, when coating on a wide base paper at high speed, at least a part of the drying step needs to be dried by a composite drying unit. It is preferable to use a product of 3 MW or more as the infrared output capability per unit of the combined drying unit, and the upper limit of the infrared output capability is preferably 25 MW or less. From the viewpoint of easy device creation, stable operation during continuous operation, and quality adjustment of coated paper, a composite type in the case of combining a composite type drying unit and a hot air drying system, which is a preferred embodiment in the present invention. The infrared output capability per unit of the drying unit is more preferably in the range of 4 to 10 MW.

  After forming a coating layer by the above, the smoothing process by a calendar apparatus is performed. As the calendar device, a hard nip calendar, a super calendar, a soft calendar, a gloss calendar, a thermal calendar, a compact calendar, a mat super calendar, a mat calendar, a roughened calendar, etc. are generally used. In particular, the smoothness and gloss of coated paper are improved by passing between nips or groups of nips formed by a combination of an elastic roll whose surface is made of resin and a heat roll that is a heated metal roll. When the heat calender to be used is employed, it is preferable that a coated paper for double-sided printing having excellent quality can be obtained while maintaining good operability and having excellent front and back.

  In general multi-nip calenders, the lower the nip, the higher the linear pressure due to the roll's own weight, making it easier to increase the gloss and smoothness of the coated paper surface in contact with the metal roll at the lower nip. Also easy to rise. For this reason, it is easier to independently control the gloss / smoothness of the coated paper front and back to the desired level, and the combination of the metal roll and elastic roll is inclined so that the influence of the calender roll's own weight can be reduced. A multi-nip calender and a vertically arranged multi-nip calender having a mechanism capable of canceling the roll weight can be exemplified as a more preferable form.

  In order to perform the smoothing process in the calendar at high speed, the metal roll is used at a temperature higher than the room temperature where the calendar is installed. The surface temperature of the metal roll of the calendar is preferably 80 to 230 ° C. in order to express the calendar treatment effect and avoid roll contamination due to excessive temperature rise.

  There is no particular limitation on the method of heating the metal roll of the calendar, and internal or external heating method using electromagnetic induction action, heating medium heating that introduces and circulates heating medium such as pressurized steam, hot water, silicone oil etc. in the roll Any of the methods can be adopted, but from the viewpoint of energy efficiency, a heating medium circulation method is preferably used. Also, various cooling devices can be used in combination to prevent excessive temperature rise at the end of the roll.

  The surface roughness of the metal roll of the calender is not particularly limited. However, in order to facilitate the manufacture of the metal roll and to avoid the decrease in operability and opacity caused by the calender roll contamination due to the calender temperature and linear pressure increase, The arithmetic average roughness Ra specified by JIS B0601-2001 is preferably 0.05 to 0.5 μm.

  The material of the metal roll is not particularly limited, but forged steel such as ductile forged steel, chilled cast iron, chrome chilled cast iron, and the like are preferably used, and various metal rolls plated with chromium as surface processing can also be used. Although there is no particular limitation on the hardness of the metal roll, in order to carry out the calender treatment stably, a material having a Vickers hardness of JIS Z2244 of 450 to 700 HV, more preferably 500 to 600 HV is preferably used. The

  The material of the elastic roll of the calendar is not particularly limited, but a fiber roll using wool, cotton, aramid fiber, epoxy resin, polyisocyanate resin, urethane resin, urethane rubber, vulcanized rubber, silicone resin, polyarylate Resin, vinylidene fluoride resin, polyphenylene sulfide resin, phenol resin, unsaturated polyester resin, polyacetal resin, polyimide resin silicone resin, polyarylate resin, vinylidene fluoride resin, polyphenylene sulfide resin, phenol Examples thereof include resins, unsaturated polyester resins, polyacetal resins, polyimide resins, and resin-based rolls such as resins containing aromatic polyamines and silicon-based modifiers in the resins.

  The elastic roll forms a nip opposite to the metal roll, and may contact the heated metal roll directly when paper is cut. For this reason, it is preferable to use an elastic roll having a heat resistant temperature of preferably 120 ° C. or higher, more preferably 130 ° C. or higher. The upper limit of the preferred range is not particularly limited, but the upper limit is about 240 ° C. due to production limitations.

  In addition, as the surface hardness of the elastic roll, from the viewpoint of avoiding the occurrence of uneven gloss and uneven density on the order of several mm to sub mm on the coated paper, which is caused by the unevenness of the coated paper before the calendar being compressed. The upper limit of Shore D hardness measured in accordance with ISO 7619 is preferably 96 or less, and more preferably 94 or less. Further, from the viewpoint of avoiding breakage of the elastic roll due to internal heat generation due to roll rotation under nip pressure, the lower limit of the Shore D hardness is preferably 88 or more, and more preferably 90 or more. As the elastic roll, in view of heat resistance, hardness, and operability, a resin roll within the preferable heat resistant temperature / hardness range can be mentioned as the most preferable form.

  Further, both the elastic roll and the metal roll undergo thermal deformation due to temperature changes. In order to avoid nip pressure fluctuation in the width direction due to thermal deformation and / or to avoid nip pressure fluctuation due to deformation of the roll itself regardless of temperature, the nip pressure can be controlled for each zone divided in the width direction. It is preferable to use a roll provided with a control mechanism. If the zone width of the mechanism is too wide, it is difficult to obtain the effect of zone control, while if it is too narrow, the internal mechanism becomes complicated and roll creation becomes difficult. Preferably it is 100-180 mm.

  Furthermore, it is also possible to use a suitable combination of a water coating device, an electrostatic humidifier, a steam humidifier, and the like for humidity control and humidification of coated paper before and after finishing by a calendar.

  As an arrangement method of the calendar for performing the smoothing treatment, after providing the pigment coating layer on the base paper and drying, after off-calendering for performing the calendar processing after winding once, and after providing the pigment coating layer on the base paper and drying There is an on-calendar form in which the calendar process is performed as a continuous process without winding, but any form may be used.

  After the calendar process, the coated paper is wound up in a winding form by a winder and used for a subsequent process. In the post-process, it is finished in a winding form so as to have a desired width and / or a winding width smaller than the winding width in the winder, or a flat size of a desired size ( Sheet).

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these ranges. In the examples, “parts” and “%” indicate “parts by mass (solid component)” and “mass%” unless otherwise specified.

Example 1 (Reference Example)
<Preparation of base paper>
(Preparation of base paper)
Using a Lo-solids digester (manufactured by Andritz Co., Ltd.), hardwood chips composed of acacia mangum: eucalyptus grandis = 30: 70 (mass ratio) were kraft-cooked by the Lo-solids cooking method. The white liquor is prepared with a sulfidity of 28, and the white liquor addition rate is divided into 10% per chip dry weight, 8% in the cooking zone and 2% in the washing zone as active alkali. The cooking temperature was 146 ° C. After digesting the chips after cooking, unbleached pulp was obtained through a washing process, a screen process, and a washing process again.

  To the unbleached pulp, 1.7% of caustic soda and 1.8% of oxygen per weight of dry pulp were added, and two-stage alkaline oxygen bleaching was performed under the conditions of a pulp concentration of 10% and 98 ° C. for 50 minutes. Caustic soda was added all at once in the first stage, and oxygen gas was added 1.0% in the first stage and 0.8% in the second stage, and added in portions. The pulp after alkaline oxygen bleaching was washed in the washing step.

  After 1.2% sulfuric acid was added to the pulp after the alkali oxygen bleaching and the pulp concentration was 10%, 60 ° C. and 60 minutes, the pulp was washed in the washing step. Next, after adding 0.5% ozone and 0.5% chlorine dioxide per weight of dry pulp, medium concentration ozone / chlorine dioxide bleaching was performed at a pulp concentration of 10%, 58 ° C. for 60 minutes, and then washed. It was washed in the process. Next, 1.0% caustic soda and 0.1% hydrogen peroxide per weight of dry pulp are added, and after alkali extraction under conditions of pulp concentration 10%, 60 ° C, 90 minutes, washing treatment is performed in the washing step. did. Finally, 0.2% of chlorine dioxide is added per absolute dry pulp weight, chlorine dioxide bleaching is performed under the conditions of 10% pulp density, 70 ° C, 120 minutes, and then washed in the washing step to obtain slurry-like bleaching. Pulp A was obtained.

After adding 10 parts of light calcium carbonate (trade name: Tama Pearl TP-121, manufactured by Okutama Kogyo Co., Ltd.) as a filler to 100 parts of the above bleached pulp A, 0.5% aluminum sulfate, cation with respect to the total solid content of the pulp slurry Starch (trade name: Ace K100, manufactured by Oji Cornstarch Co., Ltd.) 0.5%, alkyl ketene dimer sizing agent (trade name: Size Pine K-287, manufactured by Arakawa Chemical Co., Ltd.) 0.1%, polyacrylamide (trade name: Police 0.2% of TRON 851 (manufactured by Arakawa Chemical Co., Ltd.) was sequentially added to prepare a 1% -concentration stock. A paper layer is formed from this stock by a gap former at an operating papermaking speed of 1200 m / min, squeezed with a press including two shoe presses, and further subjected to a pressing process consisting of one press with a multi-cylinder dryer. It dried and obtained the base paper of 90 g / m < ² > from which the aqueous coating liquid coating width which forms a pigment coating layer will be 8.2 m.

<Preparation of aqueous coating liquid A for pigment coating layer>
For 100 parts of heavy calcium carbonate (trade name: Hydrocurve 60, manufactured by Bihoku Flour Industries), 4 parts of starch (trade name: Ace C, manufactured by Oji Cornstarch Co., Ltd.), styrene-butadiene copolymer Add 8 parts of latex (trade name: OJ-3000H, manufactured by JSR), add antifoaming agent and dye sequentially as auxiliary agents, and then add water to add aqueous coating for pigment coating layer with a solid content concentration of 65%. A working liquid A was obtained.

<Preparation of aqueous coating liquid B for pigment coating layer>
100 parts of kaolin (trade name: Milagros J, manufactured by BASF) are sequentially added to an aqueous solution to which 0.1 part of a dispersant (trade name: Aron T-50, manufactured by Toagosei Co., Ltd.) is added, and dispersed with a Coreless disperser. A pigment slurry was prepared. For the mixture of 50 parts of pigment in the pigment slurry and 50 parts of heavy calcium carbonate (trade name: Hydrocurve 90, manufactured by Bihoku Flour Industry Co., Ltd.), starch (trade name: Ace C, supra) as an adhesive is used. ) 2 parts, 10 parts of styrene-butadiene copolymer latex (trade name: OJ-3000H, supra), 0.3 part of PVA (trade name: PVA105, manufactured by Kuraray Co., Ltd.) are added and further increased as an auxiliary agent. A sticky agent, an antifoaming agent, a lubricant, an antiseptic, and a dye were sequentially added, and water was further added to obtain an aqueous coating liquid B for a pigment coating layer having a solid content concentration of 64%.

<Preparation of coated paper>
On the base paper made under the above conditions, the aqueous coating liquid A was coated on both sides with a blade coater so that the dry weight was 9 g / m ^{2 on} one side at a coating speed of 1200 m / min, and the water content was 5 with a hot air drier. Dry to 0.0%. Subsequently, the aqueous coating liquid B is coated on the coated surface with a blade coater so that the dry weight is 10 g / m ^{2 on} one side, and a combined type combining a gas combustion type infrared drying method and an air floating hot air drying method. It dried so that it might become moisture 5.0% only with a drying unit (Solaronics make, brand name: UniDryer V2). Thereafter, thermal calendar treatment was performed to obtain a coated paper of 128 g / m ² .

Example 2
In Example 1 (Reference Example) , in the drying after the aqueous coating solution B was applied, the composite type drying unit was dried until the moisture content of the coating layer was 20%, and then the moisture content was further reduced to 5.0% with a hot air dryer. A coated paper was obtained in the same manner as in Example 1 (Reference Example) except that drying was performed so that the content of the coated paper was 5%.

Example 3
In Example 2, the coating system of the aqueous coating liquids A and B was changed from the blade coating system to the roll coating system, and the solid content concentration of the coating liquid B was changed to 60%. In the same manner, a coated paper was obtained.

Example 4
In Example 2, the starch part of the aqueous coating solution B is 2 to 4 parts, the latex part is 10 to 9 parts, and further a thickener (trade name: Somalex 270K, manufactured by Somaru Corporation) 0.1 part A coated paper was obtained in the same manner as Example 2 except that was added.

Example 5
In Example 2, the starch part number of the aqueous coating liquid B was changed from 2 parts to 1.1 parts, the latex part number was changed from 10 parts to 11 parts, and the same procedure as in Example 2 was performed except that the thickener was not added. Coated paper was obtained.

Example 6
In Example 2, the number of heavy calcium carbonates in the aqueous coating solution B is changed to 20 parts, 30 parts of light calcium carbonate (trade name: TP-221GS, manufactured by Okutama Kogyo Co., Ltd.) is blended, and the starch parts are The coated paper was prepared in the same manner as in Example 2 except that the content was changed from 2 parts to 1.2 parts, the number of latex parts from 10 parts to 11 parts, the thickener was not added, and the coating solid content concentration was changed to 61%. Obtained.

Example 7
In Example 2, a coated paper was obtained in the same manner as in Example 2 except that the coating width of the pigment coating layer was changed to 5 m.

Example 8
In Example 2, a coated paper was obtained in the same manner as in Example 2 except that the coating speed of each pigment coating layer was changed to 1500 m / min.

Example 9
In Example 2, coated paper was obtained in the same manner as in Example 2 except that drying after application of the aqueous coating liquid A was performed using the composite drying unit.

Example 10
In Example 2, a coated paper of 110 g / m ² was obtained in the same manner as in Example 2 except that the aqueous coating liquid A was not applied and dried.

Example 11
<Preparation of aqueous coating solution C for pigment coating layer>
For 100 parts of heavy calcium carbonate (trade name: Hydrocurve 90, supra), 6 parts of starch (trade name: Ace C, supra), styrene-butadiene copolymer latex (trade name: OJ) -3000H, supra) 5 parts, PVA (trade name: PVA105, manufactured by Kuraray Co., Ltd.) 0.3 part, and further adding a thickener, antifoaming agent, lubricant, preservative, and dye as an auxiliary agent Further, water was added to obtain an aqueous coating solution C for a pigment coating layer having a solid content concentration of 61%.

<Preparation of coated paper>
In Example 2, 128 g / m ² coated paper was obtained in the same manner as in Example 2 except that the aqueous coating liquid C was applied and dried in place of the aqueous coating liquid B.

Comparative Example 1
In Example 1 (Reference Example) , a coated paper was obtained in the same manner as Example 1 (Reference Example) except that any drying process was performed only with a hot air dryer.

Comparative Example 2
In Example 1 (Reference Example) , except that the starch part of the aqueous coating liquid B was changed from 2 parts to 0.5 part, the part of latex was changed to 11 parts, and no thickener was added. A coated paper was obtained in the same manner as in Example 1 (Reference Example) .

Comparative Example 3
In Example 6, a coated paper was obtained in the same manner as in Example 6 except that the starch part of the aqueous coating liquid B was changed from 1.2 parts to 0 parts and the number of latex parts was changed to 12 parts.

Comparative Example 4
In Comparative Example 3, a coated paper was obtained in the same manner as in Comparative Example 3, except that any drying step was performed only with a hot air dryer.

Comparative Example 5
In Example 6, a coated paper was obtained in the same manner as in Example 6 except that the drying step of the aqueous coating liquid B was performed only with a hot air dryer.

Comparative Example 6
In Example 1 (Reference Example) , all the drying steps were first performed with a gas-fired infrared dryer and then dried with a hot air dryer so that the water content was 5.0%. The coated paper was obtained in the same manner as in Example 1 (Reference Example) .

Comparative Example 7
In Example 7, coated paper was obtained in the same manner as in Example 7 except that any drying process was performed only with a hot air dryer.

Comparative Example 8
In Example 8, a coated paper was obtained in the same manner as in Example 8, except that the aqueous coating liquids A and B were dried using only a hot air dryer.

Comparative Example 9
In Example 10, a coated paper was obtained in the same manner as in Example 10 except that the drying step of the aqueous coating liquid B was performed only with a hot air dryer.

Comparative Example 10
In Example 11, a coated paper was obtained in the same manner as in Example 11 except that the drying step of the aqueous coating liquids A and C was performed only with a hot air dryer.

<Evaluation method>
The coated paper for printing obtained above was evaluated by the following evaluation method, and the pressure dehydration amount of the aqueous coating liquids A and B or C and the quality results of the coated paper are shown in Table 1.
The ink drying property and ink unevenness were measured by selecting 11 points in the width direction. Eleven points are 10cm from both edges of the coating, 1 point each (a, b), 1 point (c) in the middle of the coated paper, 4 points so that the distance between a and c is equal, and so on 4 points were chosen between b and c.

(Measurement of pressurized dehydration amount of coating liquid)
The amount of pressure dehydration of the aqueous coating solution was determined by Kaltec Scientific, Inc. It measured using the manufactured AA-GWR water retention meter. As measurement conditions, pressure was applied at an applied pressure of 100 kPa and a pressurization time of 30 seconds, and the filter paper No. The moisture dehydrated from the coating solution was absorbed in 2, and the pressure dehydration amount (g / m ² ) of the coating solution was determined from the change in the filter paper weight before and after the measurement.

(Blank gloss)
Using a gloss meter (model: GM-26D, manufactured by Murakami Color Research Laboratory Co., Ltd.), according to ISO 8254-1 (1999), a value measured under the condition of an incident angle / reflection angle of 75 degrees is used as the glossiness of blank paper. It was.

(Ink drying)
Printed using 0.6 cc of printing ink (trade name: Fusion-G, black ink, S type, manufactured by Dainippon Ink Co., Ltd.) with RI printing tester, 1 minute, 3 minutes, 5 minutes, 10 minutes Later, the white paper and the printing surface were overlapped, and again niped by an RI printing tester, and the density of the ink transferred to the white paper was visually evaluated. Evaluation was performed by five-step evaluation of 5 (excellent) -1 (poor).
Further, an ink drying average point of 11 points in the width direction and a difference between the highest score and the lowest score (denoted as score difference in Table 1) were obtained. The higher the average score, the better the ink drying property, and the smaller the score difference, the smaller the variation in the ink drying property in the width direction, and the better the quality.

(Surface strength)
Using an RI printing tester, printing was performed a plurality of times using 0.6 cc of printing ink (ink for paper test, manufactured by Toyo Ink Co., Ltd.), and the degree of picking on the printed surface was visually evaluated. Evaluation was performed by five-step evaluation of 5 (excellent) -1 (poor).

(Ink unevenness)
In the RI printing tester, printing was performed using 0.3 cc of printing ink (trade name: TOYOKING TKU CC Ai, manufactured by Toyo Ink Co., Ltd.) for the first color, and different printing inks for the second color (ink red for paper testing, Toyo Ink Co., Ltd.) 0.3 cc, and the second color after the first color printing is changed to 30 seconds, 60 seconds, 90 seconds, 120 seconds, 180 seconds, 240 seconds, 300 seconds. Ink unevenness of the ink was visually evaluated. Of the overprinting results in the above time group, the most inferior ink unevenness was evaluated as unevenness of the coated paper, and the evaluation was performed in a 5-step evaluation of 5 (excellent) -1 (inferior). It was.
Furthermore, the average ink spot unevenness of 11 points in the width direction, and the difference between the highest and lowest scores (shown as score difference in Table 1) were obtained. The higher the average score, the less ink unevenness occurs, and the smaller the difference in the number of points, the smaller the unevenness of ink unevenness in the width direction.

  As is apparent from Table 1, in any of Examples 1 to 11 of the present invention, there is no occurrence of unevenness in the printing process, excellent ink drying properties, and particularly no fluctuation in print quality in the width direction, and stable. A coated paper having the desired quality is obtained.

Claims (6)

A method for producing a coated paper for printing having a pigment coated layer, wherein the base paper constituting the coated paper is obtained by paper making with a gap former type paper machine, and comprises at least one layer constituting the coated paper After the pigment coating layer is provided by coating on a base material containing 1 part by mass or more of starch (solid content) with respect to 100 parts by mass of all pigments and running at 1000 m / min or more, dried in the drying step, at least part of the drying step is dried in a complex type drying unit which combines an infrared drying method and a hot air drying method, in the drying step, dried composite drying unit above, further hot air A method for producing a coated paper for printing, which is dried by a drying method. A method for producing a coated paper having two or more pigment coated layers on one side, wherein the base paper constituting the coated paper is obtained by paper making with a gap former type paper machine, and constitutes the coated paper The outermost pigment coating layer contains 1 part by mass or more of starch (solid content) with respect to 100 parts by mass of all pigments, and is provided by coating on a substrate that runs at 1000 m / min or more. The coated coated paper for printing according to claim 1, wherein the coated paper for printing is dried in a drying step, and at least a part of the drying step is dried in a composite drying unit combining an infrared drying method and a hot air drying method. Production method. The method for producing a coated paper for printing according to claim 1, wherein the infrared drying method is a gas combustion infrared drying method, and the hot air drying method is an air floating hot air drying method. The manufacturing method of the coated paper for printing as described in any one of Claims 1-3 whose coating width in which a pigment coating layer is formed is 5.5 m or more. The method for producing a coated paper for printing according to any one of claims 1 to 4 , wherein the pigment coating layer is provided by a blade coating method. To any one of claims 1 to 5, pressurized圧脱water of the aqueous coating solution for forming the outermost pigment coating layer as measured under the following condition is characterized by a 20 to 120 g / m ² The manufacturing method of the coated paper for printing of description.
(Measurement condition)
Pressure dehydration amount when using a membrane filter with a pore size of 0.1 μm under the conditions of a pressure of 100 kPa and a pressurization time of 30 seconds with a Kaltec Scientific AA-GWR water retention meter .