Method for producing pigment-coated paper using bevel blade coating scheme

Abstract

Provided is a method for producing pigment-coated paper provided with base paper and a pigment coating layer, the method comprising a step 1 for providing a pigment coating layer using a bevel blade coating scheme, the step 1 being performed under the following conditions:　the coating speed is 1,000 m / min or less, the blade thickness in the blade coating is 0.6 mm or less, a pigment coating solution contains kaolin as a pigment, and the single-side coating amount per coat is 8.0 g / m2 or greater.

Description

Manufacturing method of pigment coated paper using bevel blade coating method

[0001] The present invention relates to a method for producing pigment coated paper using a bevel blade coating method.

[0002] Pigment-coated paper (hereinafter simply referred to as "coated paper") is widely used not only in the printing paper field for books, catalogs, posters, magazines, art magazines, etc., but also in recent years in the field of packaging materials such as paper cartons, boxes, and containers. With the expansion of applications and advances in printing technology, the demands for print quality on paper have also increased. Therefore, in addition to the qualities of coated paper, such as whiteness and white paper gloss, the demands for quality, such as print gloss and smoothness after printing, and suitability for processing after printing, have also increased.

[0003] In the production of coated paper, various coating methods are used, such as blade coaters, roll coaters, rod blade coaters, bar coaters, air knife coaters, curtain coaters, die coaters, slot coaters, slide coaters, and spray coaters. Of these, blade coaters are preferably used for varieties that require high quality. The reason for this is that coated paper coated with a blade coater has the advantage that it is easier to improve quality aspects such as white paper gloss and smoothness compared to coated paper coated with other coating methods.

[0004] Blade coaters are available in bent and bevel types. The bent method adjusts the coating weight by pressing the blade surface against the paper. With the bent method, the closer the blade is to the paper (pressure), the larger the contact area becomes, resulting in less force per unit area applied to the paper. As a result, the gap between the paper and the blade increases, reducing the amount of coating liquid scraped off and resulting in a higher coating weight. On the other hand, the bevel method holds the tip of the blade vertically against the paper. The lower the blade pressure, the lower the force per unit area applied to the cutting edge, making the blade more flexible. As the coating passes between the blade and the paper, the shear of the coating acts to push back the blade. Therefore, a flexible blade increases the gap between the paper and the cutting edge. As a result, the lower the blade pressure, the higher the coating weight. The bevel coating method is often used in high-speed coating applications, where shear is more likely to occur during coating, increasing the amount of coating liquid adhered. For example, Patent Document 1 discloses that coated paper was produced at a coating speed of 1200 m / min using a bevel blade coater with a jet fountain supply system.

[0005] Japanese Patent Application Laid-Open No. 2006-152528

[0006] If the blade pressure is too weak in bevel coating to obtain a high coating weight at low coating speeds, the blade tends to bend excessively due to the mechanism described above. As a result, the blade flutters without applying pressure to the coated paper surface, causing chattering, which results in poor coating surface texture. Furthermore, if the blade pressure is excessively weak, an excessive coating weight is applied to the paper surface, resulting in operational problems such as increased drying load and roll contamination. Therefore, adjusting the blade pressure to weaken is technically more difficult than adjusting it to strengthen it. In light of these circumstances, the present invention aims to provide a method for producing coated paper with a high coating weight and excellent surface texture using a bevel-type blade under low-speed coating conditions.

[0007] The inventors have found that the present invention can solve the above-mentioned problems. That is, the above-mentioned problems are solved by the following. Aspect 1 A method for producing pigment coated paper comprising a base paper and a pigment coating layer, comprising step 1 of providing the pigment coating layer by a bevel blade coating method, wherein step 1 is carried out under the following conditions: the coating speed is 1000 m / min or less, the blade thickness in the blade coating is 0.6 mm or less, the pigment coating liquid contains kaolin as a pigment, and the coating amount per one coating is 8.0 g / m ２ A method for producing pigment coated paper, wherein the pigment coating contains 10 to 60 parts by mass of kaolin per 100 parts by mass of pigment. Aspect 2 A method for producing pigment coated paper according to Aspect 1, wherein the pigment coating contains 10 to 60 parts by mass of kaolin per 100 parts by mass of pigment. Aspect 3 A method for producing pigment coated paper according to Aspect 1 or 2, wherein the pigment coating has a high shear viscosity of 30 mPa·s or more. Aspect 4 A method for producing pigment coated paper according to any of Aspects 1 to 3, wherein the pigment coating contains 10 parts by mass or more of an adhesive per 100 parts by mass of pigment. Aspect 5 A method for producing pigment coated paper according to any of Aspects 1 to 4, comprising providing two pigment coating layers by a bevel blade coating method, one or both of which are provided by step 1.

[0008] The present invention provides a method for producing coated paper with a high coating weight and excellent surface feel under low-speed coating conditions using a bevel-type blade.

[0009] The present invention will be described in detail below. In the present invention, "to" includes its endpoints. That is, "X to Y" includes the values ​​of X and Y.

[0010] 1. Manufacturing method of pigment coated paper Pigment coated paper comprises base paper and a pigment coating layer. The manufacturing method of pigment coated paper of this embodiment comprises step 1 of providing a pigment coating layer by a bevel blade coating method. Step 1 includes the following steps: 1) a coating speed of 1000 m / min or less, 2) a blade thickness in the blade coating of 0.6 mm or less, 3) the pigment coating liquid used in step 1 contains kaolin as a pigment, and 4) the coating amount per one side is 8 g / m ２ It will be carried out under the above conditions.

[0011] (1) Pigment Coating Liquid Used in Step 1 1) Kaolin The pigment coating liquid used in Step 1 contains kaolin as a pigment. The pigment used in the pigment coating liquid is also called a white pigment. The amount of kaolin affects the surface texture. From this perspective, the amount of kaolin is preferably 10 to 60 parts by mass, more preferably 20 to 50 parts by mass, per 100 parts by mass of pigment. If the amount of kaolin is greater than the above range, blade edge contamination during coating may increase, potentially causing streaks. If the amount of kaolin is less than the above range, smoothness may decrease. Furthermore, since kaolin affects the viscosity of the coating, if the amount is greater than the above range, the viscosity increases too much, causing coating unevenness, and if the amount is less than the above range, the viscosity decreases too much, making it impossible to ensure a sufficient coating amount. Pigments other than kaolin are not limited as long as they are pigments commonly used in the relevant field. However, from the perspective of ease of availability, examples of such pigments include heavy calcium carbonate and light calcium carbonate. In a preferred embodiment, the pigment other than kaolin is heavy calcium carbonate or light calcium carbonate.

[0012] 2) Adhesive The pigment coating liquid preferably contains 10 parts by mass or more of an adhesive per 100 parts by mass of the pigment. From the viewpoint of printability and coatability, the amount of adhesive is preferably 10 to 30 parts by mass, more preferably 13 to 20 parts by mass, per 100 parts by mass of the pigment.

[0013] Known adhesives can be used. Examples of such adhesives include latexes such as styrene-butadiene copolymers, styrene-acrylic copolymers, ethylene-vinyl acetate copolymers, butadiene-methyl methacrylate copolymers, vinyl acetate-butyl acrylate copolymers, maleic anhydride copolymers, and acrylic acid-methyl methacrylate copolymers; polyvinyl alcohols such as fully saponified polyvinyl alcohol, partially saponified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, and acetoacetyl-modified polyvinyl alcohol; proteins such as casein, soy protein, and synthetic protein; starches such as oxidized starch, cationic starch, urea phosphate esterified starch, and etherified starch such as hydroxyethyl etherified starch, and dextrin; cellulose derivatives such as carboxymethyl cellulose, hydroxyethyl cellulose, and hydroxymethyl cellulose; and crosslinker-modified starches modified with various crosslinking agents. These adhesives can also be used in combination.

[0014] In the present invention, it is preferable to contain latex. The amount of latex blended is preferably 5 to 20 parts by mass, more preferably 6 to 18 parts by mass, and even more preferably 7 to 16 parts by mass, per 100 parts by mass of pigment. If the amount of latex blended is too high, the air resistance of the coated paper increases, which may cause problems such as blisters during printing.

[0015] In addition, when two pigment coating layers are provided, it is preferable that the amount of latex compounded in the under layer and the top layer is less than that in the top layer, which can ensure surface strength, print gloss, water resistance, and fold crack resistance.

[0016] In a preferred embodiment, latex and starch can be used in combination. The mass ratio, in one embodiment, is latex:starch = (1):(0.5-2.0), preferably (1):(0.7-1.5), and more preferably (1):(0.8-1.2). In particular, when two pigment coating layers are provided, it is preferable to use a combination of latex and starch as adhesives in the underlayer. This is because it is possible to obtain pigment coated paper that achieves both a sufficient coating weight by improving paint water retention and water-resistant peelability. Furthermore, by keeping the mass ratio within the above range, it is possible to suppress the occurrence of fold cracks during post-processing, particularly when used for packaging material applications.

[0017] 3) Other Components In addition to the pigments and adhesives described above, the pigment coating liquid may contain various auxiliary agents, such as surfactants, pH adjusters, viscosity adjusters, water retention agents, softeners, gloss-imparting agents, waxes, dispersants, flow modifiers, conductive inhibitors, stabilizers, antistatic agents, crosslinking agents, sizing agents, fluorescent brighteners, colorants, ultraviolet absorbers, antifoaming agents, waterproofing agents, plasticizers, preservatives, and fragrances, as needed, within limits that do not impair the desired effects.

[0018] 4) Properties The high shear viscosity of the pigment coating liquid is preferably 30 mPa s or more. The high shear viscosity is measured using a Hercules high shear viscometer (Model DV-10, manufactured by Kaltec Scientific) at a liquid temperature of 40°C, a rotation speed of 8800 rpm, and a bob F2.5. There are no upper limits for the high shear viscosity, but in one embodiment, it is 40 mPa s or less.

[0019] (2) Bevel Blade Coating As mentioned above, bevel blade coating is a coating method in which a blade is applied so that its tip surface faces the paper. The blade thickness is 0.6 mm or less. If the blade thickness exceeds 0.6 mm, it becomes difficult to increase the coating amount. Furthermore, if the blade is too thin, it will be easily pushed down during coating, causing chattering, making it difficult to obtain a smooth surface, and the blade will be easily worn. From this perspective, the blade thickness is preferably 0.3 mm or more, more preferably 0.4 mm or more.

[0020] 1) Coating amount: The coating amount on one side in step 1 is 8 g / m ２ If the coating amount is less than the lower limit, the surface texture will be poor. On the other hand, if the coating amount is too high, it will increase the drying load and cause roll contamination. From this viewpoint, the coating amount on one side per application is preferably 8.0 to 20 g / m ２ , more preferably 8.5 to 19 g / m ２ , and more preferably 9.0 to 18 g / m ２ is.

[0021] 2) Coating Speed: The present production method can achieve a high coating weight and excellent surface texture even at a low coating speed. Therefore, the coating speed is 1,000 m / min or less, preferably 700 m / min or less, and more preferably 500 m / min or less. The lower limit is not limited, but in one embodiment, it is 200 m / min or more.

[0022] 3) Number of Pigment Coating Layers The number of pigment coating layers formed by bevel blade coating is not limited. When there are multiple pigment coating layers formed by bevel blade coating, there are two modes: a first mode in which all of the pigment coating layers are formed by process 1, and a second mode in which some of the pigment coating layers are formed by process 1. For convenience, the pigment coating layer formed by process 1 will be referred to as "pigment coating layer 1," and the pigment coating layers formed by processes other than process 1 will be referred to as "pigment coating layer 2." In the second mode, pigment coating layer 1 is preferably present as the outermost layer.

[0023] The conditions for forming the pigment coating layer 2 are not limited. However, in one embodiment, it is preferable that the pigment coating layer 2 is formed under the same conditions as in step 1, except that kaolin is not contained. In particular, it is preferable that the pigment coating layer 2 is formed under the following conditions. The step according to the following conditions is also referred to as step 2. Coating speed: 1000 m / min or less. Blade thickness in blade coating: 0.6 mm or less. Pigment coating liquid: does not contain kaolin as a pigment, or contains less than 10 parts by mass of kaolin per 100 parts by mass of pigment. The pigment other than kaolin is preferably calcium carbonate. Coating amount per one side: 10 g / m ２ That's all.

[0024] The number of pigment coating layers formed by bevel blade coating is preferably one or two, more preferably two. When the number of pigment coating layers formed by bevel blade coating is within this range, a high coating weight and excellent surface texture can be achieved. In particular, when two layers are used, the target coating weight can be achieved by applying the coating in two separate steps. Increasing the coating weight per step can result in chattering, as described above, which can deteriorate the surface texture. Therefore, by applying the coating in two separate steps, the coating weight per layer can be adjusted appropriately, ensuring a sufficient final coating weight while maintaining a good surface texture. Therefore, the following embodiments exist: A first pigment coating layer is formed on the base paper in step 1, followed by a second pigment coating layer in step 1; A first pigment coating layer is formed on the base paper in step 2, followed by a second pigment coating layer in step 1; In this specification, "forming a layer on the base paper" means "forming a layer above the base paper." Therefore, the above embodiment includes an embodiment in which another layer (such as a clear coating layer) is provided on the base paper, and the first pigment coating layer is provided on top of that.

[0025] (3) Base Paper 1) Pulp Known pulps can be used for the base paper. Examples of known pulps include chemical pulp, groundwood pulp (GP), refined groundwood pulp (RGP), thermomechanical pulp (TMP), chemothermomechanical pulp (CTMP), chemi-ground pulp (CGP), semi-chemical pulp (SCP), and recycled paper pulp. In the present invention, it is preferable to use chemical pulp. Chemical pulp includes those produced by the kraft pulp method and those produced by the sulfite pulp method. Both can be used in the present invention, but chemical pulp produced by the kraft method is preferred in terms of production costs. From the viewpoint of brightness and the like, the content of chemical pulp in the raw material pulp is preferably 60% by mass or more of the total pulp, more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more.

[0026] 2) Filler Known fillers may be used in the base paper. Examples of known fillers include inorganic fillers such as heavy calcium carbonate, light calcium carbonate, clay, silica, light calcium carbonate-silica composite, kaolin, calcined kaolin, delaminated kaolin, white carbon, talc, magnesium carbonate, barium carbonate, barium sulfate, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, zinc hydroxide, zinc oxide, titanium oxide, and amorphous silica produced by neutralizing sodium silicate with a mineral acid; and organic fillers such as urea-formalin resin, melamine resin, polystyrene resin, and phenolic resin. Among these, heavy calcium carbonate and light calcium carbonate, which are typical fillers used in neutral papermaking and alkaline papermaking, are preferably used to improve opacity. Light calcium carbonate is more preferred as the calcium carbonate used as a filler. The filler content in the paper is not particularly limited, but is preferably 1 to 40% by mass, and more preferably 5 to 35% by mass. Considering the strength of the base paper, the content is more preferably 8 to 20% by mass.

[0027] 3) Others: Known papermaking additives can also be used. For example, aluminum sulfate and various anionic, cationic, nonionic, or amphoteric retention aids, drainage aids, various paper strength enhancers, internal sizing agents, and other internal papermaking aids can be used as needed. Dry strength improvers include polyacrylamide and cationized starch, while wet strength improvers include polyamidoamine epichlorohydrin. These chemicals are added to the extent that they do not affect formation or runnability. Internal sizing agents include alkyl ketene dimers, alkenyl succinic anhydrides, and rosin sizing agents. Furthermore, dyes, pigments, fluorescent whitening agents, pH adjusters, defoamers, pitch control agents, slime control agents, and other additives can also be added as needed.

[0028] 4) Basis weight of base paper The basis weight of base paper for coated printing paper is 50 to 300 g / m ２ is preferred, and 80 to 270 g / m ２ More preferably, 100 to 250 g / m ２ More preferably, 150 to 220 g / m ２ is particularly preferred.

[0029] (5) Clear Coating The present manufacturing method may include a step of providing a clear (transparent) coating layer on one or both sides of the base paper. By applying a clear coating to the base paper, the surface strength and smoothness of the base paper can be improved, and the coating suitability for pigment coating can also be improved. The amount of clear coating is 0.1 to 3.0 g / m2 in solids per side. ２ is preferred, and 0.2 to 2.5 g / m ２ More preferably, it is 0.3 to 2.0 g / m ２ is.

[0030] Clear coating refers to the application (size press) of a coating liquid (surface treatment liquid) containing starches such as starch, oxidized starch, various modified starches (autogenously modified, cationically modified, etc.), and water-soluble polymers such as polyacrylamide and polyvinyl alcohol as its main components onto base paper using a coater (applicator) such as a two-roll pond size press, gate roll coater, premetaling size press, curtain coater, or spray coater. The clear coating liquid may also contain a sizing agent before application. Among these, starch is preferred.

[0031] (6) Pigment Coating by Other Methods The present production method can further include a coating step other than bevel blade coating, as long as the above-mentioned effects are not impaired. Examples of coating steps other than bevel blade coating include bent blade coating, bar coater, air knife coater, rod metering size press, pond type size press, gate roll coater, spray coater, curtain coater, etc. The coating step other than bevel blade coating may be performed before or after the bevel blade coating step, but is preferably performed before the bevel blade coating step in order to avoid impairing the surface texture of the coating performed with the bevel blade.

[0032] (7) Mechanism: This production method can achieve a high coating weight and excellent surface texture under low-speed coating conditions. The mechanism is not limited, but is presumed to be as follows: By including kaolin (preferably in combination with starch), an optimal high-shear viscosity is obtained. This allows a high coating weight to be achieved even under low-speed coating conditions. Furthermore, the use of a bevel blade allows the blade tip to be applied to the coated surface with linear pressure, thereby achieving an excellent surface texture.

[0033] 2. Pigment-Coated Paper The pigment-coated paper obtained by this production method has a high coating weight and excellent surface texture. Therefore, this pigment-coated paper is useful as coated paper for printing. Commercial printing, such as offset printing, gravure printing, and on-demand printing (laser, inkjet, and electrophotographic), can be applied to the surface of the coated printing paper. Coated printing paper is used for envelopes, books, magazines, posters, calendars, and the like. The pigment-coated paper is also useful as a packaging material for paper cartons, boxes, containers, and the like.

[0034] From the viewpoint of preventing blisters during printing, the air resistance of the pigment coated paper of the present invention is preferably 400 s / 100 ml to 2000 s / 100 ml, more preferably 500 s / 100 ml to 1600 s / 100 ml, when the pigment coated paper has one layer. Furthermore, when the pigment coated paper has two layers, the air resistance is preferably 3000 s / 100 ml to 15000 s / 100 ml, more preferably 3500 s / 100 ml to 10000 s / 100 ml. If the air resistance is too high, blisters are more likely to occur.

[0035] The present invention will be specifically illustrated by the following examples, but the present invention is not limited to the descriptions in the examples. Furthermore, parts by mass in the examples refer to parts by mass on an bone-dry basis unless otherwise specified.

[0036] (1) Coated paper with one pigment coating layer [Example 1] Coating solution A: 100% by mass of chemical pulp, basis weight 201 g / m ２Base paper of 40 parts by mass of heavy calcium carbonate A (proportion of particles with a particle size of 2 μm or less by precipitation method: 75%, D50 = 1.61 μm) as pigments, 30 parts by mass of heavy calcium carbonate B (proportion of particles with a particle size of 2 μm or less by precipitation method: 90%, D50 = 1.23 μm), and 30 parts by mass of first-grade kaolin (average particle size 2 μm, aspect ratio 10) were mixed together, and 9 parts by mass of acrylic ester-styrene copolymer latex and 9 parts by mass of starch were blended as adhesives, and water was further added to obtain coating solution A with a solids concentration of 64% by mass.

[0037] Coating solution A was applied to the base paper using a bevel blade coater (blade thickness: 0.457 mm) to a dry coating amount of 13.7 g / m per side. ２ The coating was carried out at a coating speed of 300 m / min so as to obtain coated paper.

[0038] [Comparative Example 1] Coating Solution B Coating Solution B was obtained in the same manner as in Example 1, except that 100 parts by mass of heavy calcium carbonate A was used as the pigment and the solid content concentration was 65% by mass. Next, Coating Solution B was applied to the base paper using a bevel blade coater in a dry coating amount of 12.3 g / m per side. ２ A coated paper was obtained in the same manner as in Example 1, except that the coating was carried out so that the thickness of the coated paper was as follows:

[0039] [Example 2] Coating solution C: 100% by mass of chemical pulp, basis weight 199 g / m ２ A coating solution C was prepared in the same manner as in Example 1, except that 50 parts by mass of heavy calcium carbonate B and 50 parts by mass of first-grade kaolin were mixed as pigments to give a solids concentration of 63% by mass.

[0040] Coating solution C was applied to the base paper using a bevel blade coater (blade thickness: 0.381 mm) to a dry coating amount of 10.9 g / m per side. ２ A coated paper was obtained in the same manner as in Example 1, except that the coating was carried out so that the thickness of the coated paper was as follows:

[0041] [Comparative Example 2] Coating Solution B Coating Solution B was applied to the base paper using a bevel blade coater (blade thickness: 0.600 mm) in a dry coating amount of 6.9 g / m per side. ２ A coated paper was obtained in the same manner as in Comparative Example 1, except that the coating was carried out so that:

[0042] [Reference Example 1] Bent blade coater, coating solution A, pulp containing 100% chemical pulp, basis weight 190 g / m ２ Coating Solution A was applied to the base paper using a bent blade coater (blade thickness: 0.457 mm) in a dry coating amount of 22.0 g / m2 on one side. ２ A coated paper was obtained in the same manner as in Example 1, except that the coating was carried out so that the thickness of the coated paper was as follows:

[0043] (2) Two pigment coating layers [Example 3] Coating Solution D 40 parts by mass of heavy calcium carbonate A, 30 parts by mass of heavy calcium carbonate B, and 30 parts by mass of first-grade kaolin were mixed as pigments, and 15 parts by mass of acrylic ester-styrene copolymer latex was added as an adhesive, followed by addition of water to obtain Coating Solution D with a solids concentration of 67% by mass. Coating Solution D was applied to the coated paper obtained in Comparative Example 1 using a bevel blade coater to a dry coating amount of 10.7 g / m per side. ２ A coated paper was obtained in the same manner as in Example 1, except that the coating was carried out so that the thickness of the coated paper was as follows:

[0044] [Example 4] Coating solution D: 100% by mass of chemical pulp, basis weight 199 g / m ２ Coating Solution A was applied to a base paper of 12.1 g / m2 on one side using a bevel blade coater (blade thickness: 0.381 mm). ２ The coating was carried out at a coating speed of 300 m / min so that the basis weight was 216 g / m ２ Coating Solution D was applied to the under-coated paper using a bevel blade coater in a dry coating amount of 11.8 g / m per side. ２ A coated paper was obtained in the same manner as in Example 1, except that the coating was carried out so that the thickness of the coated paper was as follows:

[0045] [Comparative Example 3] Coating solution E: 100% by mass of chemical pulp, basis weight 199 g / m ２ Onto the base paper, coating solution B was applied using a bevel blade coater (blade thickness: 0.381 mm) in a dry coating amount of 11.0 g / m2 per side. ２ The coating was carried out at a coating speed of 300 m / min so that the basis weight was 203 g / m ２ An undercoated paper of this type was obtained.

[0046] 30 parts by mass of heavy calcium carbonate B and 70 parts by mass of first-grade kaolin were mixed as a pigment, and 5 parts by mass of acrylic ester-styrene copolymer latex as an adhesive was blended therewith, followed by addition of water to obtain coating solution E with a solids concentration of 66% by mass. Coating solution E was applied to the undercoated paper using a bevel blade coater (blade thickness 0.381 mm) to a dry coating amount of 7.9 g / m per side. ２ A coated paper was obtained in the same manner as in Example 1, except that the coating was carried out so that the thickness of the coated paper was as follows:

[0047] [Example 5] Coating solution F: 100% by mass of chemical pulp as pulp, basis weight 190 g / m ２ On the base paper, coating solution A was applied using a bevel blade coater (blade thickness: 0.457 mm) in a dry coating amount of 14.0 g / m per side. ２ The coating was carried out at a coating speed of 300 m / min so that the basis weight was 208 g / m ２ An undercoated paper of this type was obtained.

[0048] 50 parts by mass of heavy calcium carbonate B and 50 parts by mass of first-grade kaolin were mixed as pigments, and 17 parts by mass of acrylic ester-styrene copolymer latex was blended as an adhesive, followed by addition of water to obtain coating solution F with a solids concentration of 62% by mass. Coating solution F was applied to the base paper using a bevel blade coater in a dry coating amount of 10.8 g / m per side. ２ A coated paper was obtained in the same manner as in Example 1, except that the coating was carried out so that the thickness of the coated paper was as follows:

[0049] Reference Example 2: Bent Blade Coater, Coating Solution G 50 parts by mass of heavy calcium carbonate B and 50 parts by mass of first-grade kaolin were mixed as pigments, and 15 parts by mass of acrylic ester-styrene copolymer latex was blended as an adhesive, followed by addition of water to obtain Coating Solution G with a solids concentration of 64% by mass. Coating Solution G was applied to the coated paper obtained in Reference Example 1 using a bent blade coater (blade thickness 0.457 mm) to a dry coating amount of 20.0 g / m per side. ２ Coated paper was obtained in the same manner as in Example 1, except that the following measurements were carried out on the obtained pigment coated paper. The results are shown in Table 1.

[0050]

[0051] It is clear that this manufacturing method can achieve a high coating weight and excellent surface feel at the same level as conventional blade coating.

[0052] (3) Measurement Methods 1) Basis Weight Measured in accordance with JIS P8124. 2) Paper Thickness Measured in accordance with JIS P8118. 3) Density Calculated from basis weight and paper thickness.

[0053] 4) Paint Properties High Shear Viscosity: Measurement was performed using a Hercules High Shear Viscometer (Model DV-10, manufactured by Kaltec Scientific) at a liquid temperature of 40°C, a rotation speed of 8800 rpm, and a bob of F2.5. Dewatering Amount: Measurement was performed using an AA-GWR Water Retention Meter (Model 150, manufactured by Kaltec Scientific). Specifically, measurement was performed using "AA-GWR Test Filters (Kaltec Scientific, INC.) GWR420" and the base paper prepared in Example 1 under conditions of a liquid temperature of 40°C, a pressure of 0.5 Bar, 40 seconds, and a liquid volume of 20 ml.

[0054] 5) Operability Blade edge contamination Contamination caused by the accumulation of color residue on the blade edge during coating was visually evaluated based on the following criteria: G: Good NG: Poor Chatter / Streak The occurrence of problems such as blade chatter and streaks during coating was evaluated on a three-point scale based on the following criteria: Good chatter / streaks means good surface feel. G: Good P: Fairly good NG: Poor

[0055] 6) Coating weight (ash content method) The coating weight was calculated by the ash content method according to JIS P 8251. 7) Air resistance Measured according to JIS P 8117.

Claims

A method for producing pigment coated paper comprising a base paper and a pigment coating layer, The method includes a step 1 of providing a pigment coating layer by a bevel blade coating method, Step 1 is carried out under the following conditions: The coating speed is 1000 m / min or less. The blade thickness in the blade coating is 0.6 mm or less. The pigment coating liquid contains kaolin as a pigment. The coating amount on one side per coat is 8.0 g / m ２ That's all. Manufacturing method of pigment coated paper.

2. The method for producing pigment coated paper according to claim 1, wherein the pigment coating liquid contains 10 to 60 parts by mass of kaolin per 100 parts by mass of pigment.

3. The method for producing pigment coated paper according to claim 1, wherein the high shear viscosity of the pigment coating liquid is 30 mPa·s or more.

4. The method for producing pigment coated paper according to claim 1, wherein the pigment coating liquid contains 10 parts by mass or more of adhesive per 100 parts by mass of pigment. 　 The method includes providing two pigment coating layers using a bevel blade coating method, The one or two layers are provided by step 1. A method for producing pigment coated paper according to any one of claims 1 to 4.

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