JP2008274524A - Method for producing coated paper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing coated paper, which is excellent in high speed operability and has little paper roughening in producing the coated paper by applying a coating solution containing a pigment and an adhesive on mechanical pulp-containing base paper and drying it to make a coated layer. <P>SOLUTION: The method for producing coated paper includes applying a coating solution containing a pigment and an adhesive on base paper and drying it to make one or more of the coated layer. In the method, paper making and coating speed is ≥1300 m/min., and a starch coating solution is applied at ≥1.0 g/m<SP>2</SP>on both surfaces of the base paper prepared by papermaking a mechanical pulp-containing paper material by a rod metering type coating apparatus, or a coating solution in which ≥13 pts.wt. starch is added based on 100 pts.wt. pigment in the coating solution is applied to undercoat at ≥3.0 g/m<SP>2</SP>on both surfaces, subsequently the coating solution containing the pigment and the adhesive is additionally applied. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a coated paper of medium quality produced at high speed, and a method for producing a coated paper with less roughening during offset rotary printing.

  In recent years, the demand for printing paper in the commercial printing field for the purpose of advertising and advertising such as flyers, catalogs, pamphlets, and direct mails is increasing. Although these commercial printed materials have low commercial value, it is important that the purpose is achieved as an advertising medium, and therefore, there is a demand for low-cost and high-quality printed products. In these applications, medium-sized coated paper containing mechanical pulp as the base paper is often used. And it is often printed by an off-wheel that is a high-speed printing method for its application purpose, but since the off-ring is a printing method that is continuously heated and dried after printing, other sheet-fed offset, rotogravure, It is a serious defect that tends to cause a unique phenomenon called roughing that cannot be seen in a printing system such as letterpress, and deteriorates the printing finish. Roughening is a phenomenon unique to medium-sized coated papers that is not seen in high-quality coated papers, and is exposed to rapid drying at high temperatures after ink or fountain solution is applied to the paper during off-wheel printing. In particular, it is said that the mechanical pulp fibers change in shape and increase the roughness of the paper surface, but the detailed mechanism is not known and sufficient countermeasures have not been elucidated.

  Applying a coating composition containing heavy calcium carbonate having a specific surface area to a base paper containing high yield pulp whose fiber fraction content has been specified so far, and fiber (see Patent Document 1) A method for improving heat set roughing by coating a coating composition containing a specific heterogeneous dual structure emulsion copolymer latex and pigment on a base paper blended with high-yield pulp with a specified fraction ( Patent Document 2), methods containing hardwood mechanical pulp (see Patent Document 3), and the like have been proposed.

However, these methods are based on the use of pulp with a specified fiber fraction, and roughening may occur during high-speed operation of an on-machine coater with a papermaking / coating speed of 1300 m / min or more.
JP-A-55-142794 JP-A-57-66196 JP 2003-49393 A

  In view of the situation as described above, the problem of the present invention is that when a coated paper having a coating layer is prepared by coating and drying a coating liquid containing a pigment and an adhesive on a base paper, An object of the present invention is to provide a method for producing a coated paper that is excellent in operability, has little roughening especially during offset rotary printing, and has excellent printability.

As a result of intensive studies, the present inventors have applied a coating liquid containing a pigment and an adhesive on a base paper and dried it to provide one or more coating layers in a coated paper manufacturing method, The paper coating and coating speed is 1300 m / min or more, and the starch coating solution is 1.0 g / m on both sides with an on-machine rod metalling coating device on the base paper on which the paper stock containing mechanical pulp is made. ^{After two} or more coatings, or after coating at least 3.0 g / m ² on both sides of a coating solution containing 13 parts by weight or more of starch with respect to 100 parts by weight of the pigment in the coating solution, We have developed a method for producing coated paper, which is characterized by applying a topcoat coating solution having an adhesive.

  According to the present invention, when producing coated paper using an on-machine coater that provides a coating layer by coating and drying a coating liquid containing a pigment and an adhesive on the base paper, it is excellent in high-speed operability. In addition, it is possible to obtain a method for producing a coated paper with less roughening and excellent fine gloss unevenness and uneven printing.

In the present invention, the paper making and coating speed is 1300 m / min or more, and on the base paper on which the stock containing deinked pulp (DIP) is made, the on-machine coater rod metalling type coating device is used. After coating the coating liquid on both sides of 1.0 g / m ² or more, or on the both sides of the coating liquid containing 13 parts by weight or more of starch with respect to 100 parts by weight of the pigment in the coating liquid. This is a method for producing coated paper, in which after ^two or more coatings are applied, a top coating solution having a pigment and an adhesive is further applied.

Using an on-machine coater, the printed surface of the medium-sized coated paper produced at a high speed of 1300 m / min or higher is rougher than the paper surface before printing, resulting in poor finish. There is a problem that a so-called roughening phenomenon occurs. In order to solve this problem, as a result of repeated examination of the composition of the coating liquid in the case of undercoating before applying the coating liquid having a pigment and an adhesive, in order to eliminate roughening, when performing the undercoating, It is effective to apply a large amount of the starch coating solution, and the roughening is greatly reduced particularly when coating on both sides of 1.0 g / m ² or more. The same tendency is also observed when a coating liquid having a pigment and an adhesive is applied to the undercoat, and in particular, a coating in which 13 parts or more of starch is blended with respect to 100 parts by weight of the pigment in the coating liquid. When the liquid was applied on both sides of 3.0 g / m ² or more, roughening was greatly reduced.

  Although these mechanisms are not clear, the mechanical pulp fibers that cause roughening can be produced by applying starch alone with an undercoat that is closer to the surface of the base paper, or by applying a paint that contains starch higher than normal paint. It is presumed that there is an effect of suppressing the shape change at the time of off-wheel printing.

  As the pulp raw material of the coated base paper of the present invention, mechanical pulp is used. Other than mechanical pulp, there is no particular limitation. Deinked pulp (DIP), softwood kraft pulp (NKP), hardwood kraft pulp (LKP), etc. that are commonly used as papermaking raw materials for printing paper It is sufficient to use one or more of these as appropriate. Examples of mechanical pulp include groundwood pulp (GP), refiner groundwood pulp (RGP), thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP), chemiground pulp (CGP), and semichemical pulp (SCP). . The deinked pulp may be any deinked pulp made from high-quality paper, medium-quality paper, low-grade paper, newspaper, flyers, magazines, etc., or unselected waste paper mixed with these. Absent. In the present invention, even when the mechanical pulp is 5% by weight or more with respect to the pulp, effects such as little roughening, fine gloss unevenness, and good printing unevenness can be exhibited, preferably 5 to 50% by weight. More preferably, it is 10 to 45% by weight. Further, in the present invention, even when a large amount of deinked pulp is blended, it is effective, and the deinked pulp is 30% by weight or more, more preferably 60% by weight or more with respect to the pulp.

  The filler used in the present invention can be arbitrarily used known, for example, heavy calcium carbonate, light calcium carbonate, clay, silica, light calcium carbonate-silica composite, kaolin, calcined kaolin, deramikaolin, magnesium carbonate, Inorganic fillers such as amorphous silica produced by neutralization by mineral production of barium carbonate, barium sulfate, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, zinc hydroxide, zinc oxide, titanium oxide, sodium silicate, Organic fillers such as urea-formalin resin, melamine resin, polystyrene resin and phenol resin can be used alone or in combination. Among these, calcium carbonate and light calcium carbonate-silica composite, which are typical fillers for neutral papermaking and alkaline papermaking, are preferably used. The filler content in the paper is 1-40% solids by weight. From the viewpoint of improving the surface property, the filler content in the paper is preferably 10 to 40% by weight, more preferably 12 to 35% by weight.

  As the internal additive, chemicals such as a dry paper strength improver, a wet paper strength improver, a drainage improver, a dye, and a neutral sizing agent may be used as necessary. Examples of the dry paper strength improver include polyacrylamide and cationized starch, and examples of the wet paper strength improver include polyamidoamine epichlorohydrin. These chemicals are added within a range that does not affect the formation and operability. Examples of neutral sizing agents include alkyl ketene dimers, alkenyl succinic anhydrides, and neutral rosin sizing agents.

  As the paper machine used for the coated base paper of the present invention, a normal paper machine such as an on-top former or a gap former is used. However, the paper jetted from the head box is sandwiched between two wires and travels. Using a gap former type paper machine that dehydrates almost evenly from both sides of the wet paper produces less roughening and good surface properties with no difference between the front and back, and a high paper speed of 1300 m / min or higher. Is preferably 1500 m / min or more, more preferably 1600 m / min or more and about 2500 m / min. Also, among the gap former paper machines, the use of a roll and blade former type gap former paper machine having a dewatering mechanism with a dewatering blade immediately after the initial dewatering with the forming roll further reduces the occurrence of roughening, and the front and back sides. Good surface properties with no difference can be obtained. Further, the press part of the paper machine of the present invention preferably uses a shoe press. When the paper making speed is high, it is preferable to process a tandem type shoe press in one or more stages in consideration of moisture after pressing. Preferably, the interlayer strength and blister resistance are improved by treating in two or more stages. The processing conditions of the shoe press are preferably 100 KN / m to 1100 KN / m, more preferably 500 KN / m to 1100 KN / m. When two or more shoe presses are used, passing the paper so that the transfer belt is in contact with the shoe press on the dryer part side is less likely to cause paper breakage and has excellent high-speed operability.

The paper machine pre-dryer and after-dryer can also use a public apparatus, and the drying conditions are not particularly limited, and can be appropriately set within the normal operating range.
In the present invention, on the base paper made as described above, after applying a starch coating solution of 1.0 g / m ² or more on both sides with a rod metaling size press coater which is a rod metalling type coating device, or Then, after applying at least 3.0 g / m ² of both sides of a pigment coating solution containing 13 parts or more of starch to 100 parts by weight of the pigment in the coating solution, a coating having a pigment and an adhesive as a top coating. By applying the working liquid, it is possible to obtain a coated paper having significantly less roughening and excellent high-speed operability. By using a rod metering size press coater at a high speed of 1300 m / min or more, there is no occurrence of boiling or mist, paper breakage hardly occurs, and good operability can be obtained, preferably 1500 m / min or more, More preferably, it is 1600 m / min or more and about 2500 m / min.

When the starch coating solution is applied on both sides of 1.0 g / m ² or more on both sides, the starch needs to be applied on both sides in a solid content of 1.0 g / m ² or more, preferably 1.0 to 4.0 g / m ^2. m ^2, more preferably from 1.0 to 3.0 g / ^{m 2.} As the starch used, starch such as oxidized starch, hydroxyethyl etherified starch, enzyme-modified starch, etc. can be used alone or mixed, and roughened because oxidized starch and hydroxyethyl etherified starch coat the paper surface. It is preferable because it is easy to suppress the above. Moreover, polyacrylamide, polyvinyl alcohol, etc. can also be mixed and used.

Further, when the pigment coating solution is undercoated, a pigment coating solution containing 13 parts or more of starch is applied on both sides to 3.0 g / m ² or more with respect to 100 parts by weight of the pigment in the coating solution. should, preferably, 3.0 g / ^{m 2} or more 10 g / ^{m 2} or less, more preferably 3.0 g / ^{m 2} or more ~6.0g / ^{m 2} or less. As pigments, conventionally used kaolin, clay, delaminated clay, heavy calcium carbonate, light calcium carbonate, talc, titanium dioxide, barium sulfate, calcium sulfate, zinc oxide, silicic acid, silicate, It is an inorganic pigment such as colloidal silica or satin white, or an organic pigment such as plastic pigment, and can be used alone or in combination of two or more. As an adhesive used for a pigment coating layer, it is necessary to mix | blend 13 weight part or more of starch with respect to 100 weight part of pigments. As the starch, starch such as oxidized starch, positive starch, urea phosphate esterified starch and etherified starch such as hydroxyethyl etherified starch can be used alone or in combination. Preferred starch is hydroxyethyl etherified starch, and the blending amount is preferably 15 parts by weight or more, more preferably 15 to 20 parts by weight. Other adhesives conventionally used include various copolymers such as styrene / butadiene, styrene / acrylic, ethylene / vinyl acetate, butadiene / methyl methacrylate, vinyl acetate / butyl acrylate, and the like. Synthetic adhesives such as polyvinyl alcohol, maleic anhydride copolymer, acrylic acid / methyl methacrylate copolymer, casein, soy protein, synthetic protein proteins, dextrin starches, carboxyethyl cellulose, hydroxyethyl cellulose, hydroxy One or more ordinary adhesives for coated paper such as cellulose derivatives such as methylcellulose can be appropriately selected and used. These adhesives are used in the range of about 1 to 15 parts by weight, more preferably about 2 to 10 parts by weight per 100 parts by weight of the pigment. In addition, if necessary, various assistants to be blended in a usual coating composition for coated paper, such as a dispersant, a thickener, a water retention agent, an antifoaming agent, a water resistance agent, a colorant, and a printability improver. Agents are used as appropriate.

In the present invention, on the base paper, 13 parts with respect to 100 parts by weight of the pigment in the coating liquid after the starch coating liquid is coated at 1.0 g / m ² or more on both sides with a rod metering size press coater. After undercoating the pigment coating liquid containing the above starch on both sides of 3.0 g / m ² or more, an overcoating liquid having a pigment and an adhesive is applied.

According to the desired quality, the topcoat coating solution is used by appropriately changing the pigment in the paint, the type of the adhesive, or the amount ratio of the pigment to the adhesive.
As the pigment used in the pigment coating layer of the present invention, conventionally used kaolin, clay, delaminated clay, heavy calcium carbonate, light calcium carbonate, talc, titanium dioxide, barium sulfate, calcium sulfate, oxidation Inorganic pigments such as zinc, silicic acid, silicate, colloidal silica, and satin white, and organic pigments such as plastic pigments can be used alone or in combination of two or more. As the adhesive used in the pigment coating layer of the present invention, conventionally used styrene / butadiene, styrene / acrylic, ethylene / vinyl acetate, butadiene / methyl methacrylate, vinyl acetate / butyl acrylate, etc. Synthetic adhesives such as polyvinyl alcohol, maleic anhydride copolymer, acrylic acid / methyl methacrylate copolymer, casein, soy protein, synthetic protein proteins, oxidized starch, positive starch, urea Appropriate selection of one or more adhesives for normal coated paper such as phosphated starch, etherified starch such as hydroxyethyl etherified starch, starches such as dextrin, cellulose derivatives such as carboxyethylcellulose, hydroxyethylcellulose, hydroxymethylcellulose Used. These adhesives are used in an amount of about 5 to 50 parts by weight, more preferably about 5 to 25 parts by weight per 100 parts by weight of the pigment. In addition, if necessary, various assistants to be blended in a usual coating composition for coated paper, such as a dispersant, a thickener, a water retention agent, an antifoaming agent, a water resistance agent, a colorant, and a printability improver. Agents are used as appropriate.

The coating amount of the overcoat coating layer of the present invention, preferably per side 2 to 30 g / ^{m 2,} more preferably from 5 to 15 g / ^{m 2,} more preferably from 5~12g / ^{m 2.}
The coated paper thus obtained can be subjected to a calendar process. The calendering process may be a super calender, gloss calender, soft calender, etc. that are usually used for smoothing coated paper, and these may be used in combination. By setting the hardness and the temperature of the metal roll within a specific range, it is possible to obtain a coated paper having excellent blank paper glossiness and surface property and high ink deposition without affecting operability. In the present invention, the surface of the outermost layer of the coated paper is subjected to a surface treatment at least 2 nips or more using a soft calender composed of a metal roll and an elastic roll. At this time, the Shore hardness of the elastic roll is D90 to 96, and the surface temperature of the metal roll at the first nip is less than 130 ° C.

  The surface temperature of the metal roll at the first nip of the soft calender in the present invention is a relatively low temperature of less than 130 ° C, preferably 50 ° C or more and less than 130 ° C, more preferably 60 to 120 ° C, and still more preferably 60 to 110 ° C. It is. If the surface temperature of the metal roll at the first nip of the soft calender is higher than 130 ° C., minute gloss unevenness tends to occur. In the present invention, when the surface temperature of the metal roll at the first nip of the soft calender is 50 ° C. or higher, the glossiness of the white paper increases, which is particularly preferable. Moreover, it is preferable that the metal roll surface temperature of 2-6 nips is 100-250 degreeC, More preferably, it is 100-200 degreeC. The calender linear pressure from the 1st to 6th nip is preferably 100 to 600 kN / m, more preferably 150 to 400 kN / m.

  The material of the elastic roll used in pair with the metal roll of the soft calender is not particularly limited, but generally at high temperature and high pressure such as modified urethane resin, epoxy resin, polyamide resin, phenol resin, polyether resin, polyacrylate resin, etc. A resin roll exhibiting durability is preferably used. Further, the hardness of the resin roll can be operated without problems by using a shear hardness of D90 to 96, preferably D92 to 96.

  The type of the soft calendar used in the present invention is preferably 4 to 8 stacks, more preferably 6 stacks in two tandem type rolls in consideration of ease of paper passing and space saving. The tandem type is a soft calender of a type in which two rolls obtained by overlapping a pair of metal rolls and elastic rolls are arranged in parallel, and is preferably a soft calender that is processed online from coating.

  In the present invention, details of the reason why an excellent coated paper can be obtained by setting the hardness of the elastic roll at the first nip and the temperature of the metal roll in a specific range in the present invention are not clear, but high-speed thermal soft In the calendering process, the first nip is processed with the highest moisture content, so the surface is more plasticized than the subsequent nip, and the influence on the expression of blank paper gloss and smoothness is greater. This is considered to be related to the nip where the thickness unevenness and moisture unevenness of the paper coating layer are easily affected and minute gloss unevenness is most likely to occur.

  In the present invention, when producing coated paper using an on-machine coater in which a coating layer containing a pigment and an adhesive is coated and dried on a base paper containing mechanical pulp to provide a coating layer. In addition, it is possible to produce a coated paper for printing that is excellent in high-speed operability, has little roughening during rotary printing, and has excellent fine gloss unevenness and uneven printing. In addition to papermaking and coating, the paper can be further integrated by adding a calendar process, and coated paper can be produced by continuously passing paper.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the examples. In addition, unless otherwise indicated, all the parts and% shown in an Example mean the solid content weight part and solid content weight%.

<Evaluation method>
(1) Roughening It measured with the paper surface analyzer FIBRO1000 made from Fibro. This measuring instrument is a measuring instrument that applies water to the surface of a sample, and after drying with an infrared lamp, evaluates the degree of swell of the surface fibers by performing image analysis with a CCD camera. The measurement was performed under the conditions of a water application amount of 8.0 g / m ² and a drying temperature of 150 ° C., and the roughening amount was evaluated by the Qty value (lines / m), which is the number of fibers raised to 0.1 mm or more from the reference line ( The smaller the Qty value, the better the roughening.)

(2) Micro gloss unevenness The micro gloss unevenness of the final product was visually evaluated in the following four stages.
◎ = No, ○ = None, △ = Slightly present, X = Gloss unevenness is very conspicuous (3) Ink setting unevenness Ink for offset printing (4 units) by Roland flat printing press M) is printed in the order of indigo → red → yellow → black at a printing speed of 8000 sheets / minute, and the obtained printed matter, in particular, two-color (indigo, red) printing portion, indigo single-color solid printing portion and halftone (50 %) The printing surface feeling (imprint unevenness, glossiness unevenness, etc.) of the printing part was visually evaluated in the following four stages.
◎ = Excellent, ○ = Good, △ = Slightly inferior, X = Inferior (4) High-speed operability Paper breakage at the press part is unlikely to occur, mist is not generated during coating, and shrinkage wrinkles during calendaring The suitability of high-speed operability with no occurrence of rolls and no scratches on the roll was evaluated.
◎ Very good, ○ Good, △ Slightly poor, × Poor [Example 1]
Light calcium carbonate as a filler is added to a pulp slurry consisting of 30 parts of deinked pulp (DIP) with a mechanical pulp content of 33% and 70 parts of LBKP so that the ash content in the paper becomes 11%, and cationized as an internal paper strength agent. The stock was adjusted by adding 4 parts of starch. Using this stock, paper was made at 1600 m / min on a roll and blade former type gap former type paper machine having two tandem shoe presses, and subsequently using an on-machine rod metering size press coater. An oxidized starch solution having a solid content concentration of 6% was applied to both sides at 1.6 g / m ² and dried to obtain 45.6 g / m ² of medium-quality coated base paper. Next, 100 parts of pigment containing 73 parts of heavy calcium carbonate and 27 parts of kaolin were mixed with 4.5 parts of oxidized starch and 8.2 parts of carboxy-modified styrene / butadiene copolymer latex as an adhesive. A coating solution having a partial concentration of 64% was prepared, and 8.3 g / m ² per side of the base paper was overcoated on both sides and dried. Further, a 2-roll / 6-stack high temperature soft calender having an elastic roll with a Shore hardness of D94 is used, the surface temperature of the metal roll at the first nip is 90 ° C., the surface temperature of the metal roll at the 2-6 nip is 130 ° C., 1 Continuous calendering was performed with the linear pressure at -6 nip set to 250 kN / m.

[Example 2]
In Example 1, instead of a pulp slurry comprising 30 parts of deinked pulp (DIP) having a mechanical pulp content of 33% and 70 parts of LBKP, 60 parts of deinked pulp (DIP) having a mechanical pulp content of 33% and 40 parts of LBKP are used. A coated paper was produced in the same manner as in Example 1 except that the resulting pulp slurry was used.

[Example 3]
In Example 1, a 2-roll / 6-stack high temperature soft calender having an elastic roll with a Shore hardness of D94 was used, the surface temperature of the metal roll in the first nip was 90 ° C., and the surface temperature of the metal roll in the 2-6 nip was 130. The surface of the metal roll at the 1st nip was used instead of continuous calendering at a temperature of 1 ° C and 6th nip at 250 ° C. instead of a continuous calender treatment with a 2 roll and 6 stack high temperature soft calender having an elastic roll with a Shore hardness of D94. A coated paper was produced in the same manner as in Example 1 except that the temperature was 120 ° C., the surface temperature of the metal rolls at 2 to 6 nips was 130 ° C., and the linear pressure at the 1st to 6th nips was 250 kN / m. .

[Comparative Example 1]
In Example 1, instead of applying a 6% solution of oxidized starch with a rod metalling size press coater, coated paper was the same as in Example 1 except that both sides were coated with 1.6 g / m ² on a gate roll coater. Manufactured.

[Comparative Example 2]
In Example 1, coated paper was produced in the same manner as in Example 1 except that 0.8 g / m ^{2 was} applied instead of 1.6 g / m ^{2 of} oxidized starch.

  Table 1 shows the results. As is clear from Table 1, the coated paper for printing of the present invention had a small Qty value and little roughening as compared to the comparative example, good fine gloss unevenness and uneven printing, and good high-speed operability. On the other hand, all of the comparative examples have a problem that the Qty value is large, the high-speed operability is poor, or the fine gloss unevenness and the print inking unevenness are bad.

[Example 4]
Add 30 parts of deinked pulp (DIP) with a mechanical pulp content of 33% and add 70 parts of LBKP as a filler (light calcium carbonate) as a filler so that the ash content in the paper is 11%. As a base material, 4 parts of cationized starch was added to prepare a paper stock. Using this stock, paper was produced at 1600 m / min with a gap-former type paper machine of a roll and blade former type having two tandem shoe presses, and subsequently using an on-machine rod metering size press coater. 100 parts of heavy calcium carbonate is blended with 15 parts of oxidized starch and 2 parts of carboxy-modified styrene / butadiene copolymer latex as an adhesive to prepare an undercoat coating solution having a solid content of 38%, and 4.0 g on both sides. / M ² was undercoated and dried to obtain 48.0 g / m ² of medium quality undercoated paper. Next, 100 parts of pigment containing 73 parts of heavy calcium carbonate and 27 parts of kaolin were mixed with 4.5 parts of oxidized starch and 8.2 parts of carboxy-modified styrene / butadiene copolymer latex as an adhesive. A coating solution having a partial concentration of 64% was prepared, and 8.3 g / m ² per side of the base paper was overcoated on both sides and dried to obtain a coated paper.

  Further, a 2-roll / 6-stack high temperature soft calender having an elastic roll with a Shore hardness of D94 is used, the surface temperature of the metal roll at the first nip is 90 ° C., the surface temperature of the metal roll at the 2-6 nip is 130 ° C., 1 Continuous calendering was performed with the linear pressure at the -6th nip set to 250 kN / m.

[Comparative Example 3]
In Example 4, as an undercoat coating solution, 15 parts of oxidized starch and carboxy-modified styrene / butadiene copolymer latex were used in place of 2 parts instead of 5 parts of oxidized starch and 10 parts of carboxy-modified styrene / butadiene copolymer latex. Produced coated paper in the same manner as in Example 4.

[Comparative Example 4]
In Example 4, a coated paper was obtained in the same manner as in Example 4 except that the coating amount of the undercoat coating solution was 2.0 g / m ² instead of 4.0 g / m ^{2 on} both sides.

  Table 2 shows the results. As is apparent from Table 2, the medium-sized coated paper for printing according to the present invention had a small Qty value and little roughening compared to the comparative example, good fine gloss unevenness and uneven printing, and good high-speed operability. . In contrast, all of the comparative examples have a relatively large Qty value and a large degree of roughening.

Claims (4)

In the method for producing coated paper, on the base paper, a coating liquid containing a pigment and an adhesive is applied and dried to provide one or more coating layers.
The papermaking and coating speed is 1300 m / min or more,
The pigment 100 in the coating liquid is coated on the base paper on which the stock containing the mechanical pulp is made with a rod metalling type coating device, and the starch coating liquid is coated at 1.0 g / m ² or more on both sides, or in the coating liquid. After undercoating at least 3.0 g / m ² on both sides of a coating solution containing 13 parts by weight or more of starch relative to parts by weight,
Furthermore, the manufacturing method of the coated paper characterized by applying the coating liquid which has a pigment and an adhesive agent.   2. The method for producing a coated paper according to claim 1, wherein the base paper is made using a gap former type paper machine.   The method for producing coated paper according to claim 2, wherein the gap former type paper machine has one or more tandem shoe presses.   The surface of the outermost layer of the coated paper is subjected to a surface treatment at least 2 nips or more using a soft calender composed of a metal roll and an elastic roll, and the Shore hardness of the elastic roll is D90 to 96. The surface temperature of the metal roll of a nip is less than 130 degreeC, The manufacturing method of the coated paper of Claims 1-3 characterized by the above-mentioned.