JP2005256187A - Cast coated paper and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cast coated paper having high productivity, excellent in face feeling, white paper glossiness and printability of cast surface and excellent in face feeling white paper glossiness and printability of non-cast surface and to provide a method for producing the cast coated paper. <P>SOLUTION: In the cast coated paper having coated layers mainly each consisting of a pigment and an adhesive on both surfaces of a base paper and obtained by applying cast processing to one side of the coated layer and finishing the paper, the base paper comprises an organic compound having action inhibiting bond between fibers of base paper and the coated layer of face opposite to a cast-processed surface comprises inorganic pigment and a plastic pigment in an amount of 5-50 pts. wt. based on 100 pts. wt. inorganic pigment. The method for producing the cast coated paper is also provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  In the present invention, a coating liquid mainly composed of a pigment and an adhesive is applied to both surfaces of a base paper to form a coating layer, and after the wet coating layer is dried, The present invention relates to a cast coated paper which is finished by applying a cast process in which one side is plasticized by re-wetting and heated to a mirror-finished drum surface (cast drum) and dried.

  Since the surface of the cast coated paper is pressed against the heated mirror drum surface by pressing the wet coated layer, it has a higher gloss than ordinary coated paper, posters, paper bags, Used for high-advertisement applications such as magazine covers. Conventionally, a polylaminated product that forms a highly glossy surface by printing and laminating it has been widely used. In recent years, the recovery rate as recycled paper has been increased due to the improvement of environmental awareness. However, cast paper without polylamination has become an environmentally friendly product because polylamination is difficult to separate in the recycling process. On the other hand, since there is no gloss improvement treatment such as polylamination after printing, it is necessary to form a very good high gloss surface at the printing stage. In particular, cast coated paper forms a highly glossy surface at the white paper stage, so if ink is placed on the image area during the printing process, the glossiness of the coated paper decreases, contrary to that of ordinary coated paper. There is a growing demand for improvement from users because it is a major issue in terms of quality compared to a polylaminated product with the same glossiness as the line part.

  In addition, when cast coated paper is used for magazine cover applications, the opposite side of the cast side is also printed, so paper called “back coat cast coated paper” with a coating layer on the non-cast side Is used. These are bound so that the cover becomes the cast surface, but the non-cast surface is frequently used as an advertisement page, so a highly visual finish is required.

  High gloss coated paper called cast coated paper is a stage where the base layer is coated with a water-based paint mainly composed of pigment and adhesive to provide a coating layer, and the coating layer is in a wet state. The coating layer is manufactured by pressing and drying on a heated metal mirror drum.

  The cast coated paper can be produced by a wet casting method in which a wet coating layer is directly pressed against a heated mirror drum to form a glossy finish (hereinafter referred to as casting), and a wet coating layer is gelled. Gelling cast method in which the heated mirror surface is pressed against the heated mirror surface and cast, and the wet coating layer is dried once, then plasticized by rewet, and then pressed against the heated mirror drum for casting. The casting method is known.

  All of these methods for producing cast coated paper are common in that the cast coated layer is in contact with the heated mirror drum surface while the cast coated layer is in a wet or plastic state and cast. However, in terms of operability and the quality of cast coated paper obtained due to the difference in the plastic state of the coating layer before casting (hereinafter, the coating layer to be cast is referred to as the cast coating layer) There are drawbacks. In the wet cast method, the viscosity of the cast coating layer is low, and if the temperature of the mirror drum surface is 100 ° C. or higher, the coating liquid boils and the coating layer is destroyed, so the mirror drum temperature is 100 ° C. or higher. I can't. Since there is no drying process before casting and the drying load is large, it is necessary to operate at a low speed.

  In the gelation cast method, the cast coating layer is gelled, so that the temperature of the mirror drum surface can be 100 ° C. or higher. However, since there is no drying process before casting and the drying load is large, a large amount of water contained in the cast coating layer must be smoothly transferred to the base paper layer to evaporate and remove when contacting the mirror drum. In addition, it is difficult to adjust the degree of gelation of the coating layer, and for this reason, when the casting process is performed at a very high speed, the quality such as the glossiness of the white paper is deteriorated.

  In the casting process, since the cast processed surface is pressed against the cast drum, the moisture in the coating layer can hardly evaporate from the surface layer of the cast processed surface, and the evaporation from the non-cast surface side is dominant. For this reason, in a cast coated paper (back coated cast coated paper) in which one side is cast with a double-sided coated paper as intended in the present invention, a coating layer is provided on the non-cast side, Compared with single-sided cast coated paper not provided with a coating layer, the air permeability resistance is high and it is difficult for steam to pass through, so the casting speed cannot be increased. Another problem is that the surface property of the non-cast surface is deteriorated due to the passage of vapor, and the blank paper feeling and the print feeling are remarkably lowered.

  In the rewet cast method, the cast coating layer is once dried before casting, so the mirror drum temperature can be raised to 90-180 ° C, and cast processing compared to the wet casting method and gelled casting method. It is a method that can increase the speed relatively and is excellent in productivity. In addition, since the amount of water evaporated during casting can be reduced, the surface property of the non-cast surface can be improved. However, since the cast coating layer has lower plasticity than the wet cast method and gelled cast method, when cast at high speed, so-called cast surface defects such as pinholes and uneven adhesion of the cast coating layer occur. There is a drawback that makes it easier to do. Further, depending on the plasticity of the coating layer on the non-cast surface, there are cases where the air resistance is high and the surface property is lowered.

Various methods have been proposed to solve such problems. For example, a method has been proposed in which a plastic pigment and a latex having a minimum film-forming temperature of less than 0 ° C. are blended in a cast coating layer (see Patent Document 1). The cast coated paper obtained by this method is excellent in white paper gloss, but has insufficient air resistance and low production efficiency. Moreover, the cast surface and the surface feeling obtained were at an insufficient level. A method of blending a hollow plastic pigment into a cast undercoat layer has been proposed (see Patent Document 2). Although the production efficiency of the cast coated paper obtained by this method was improved as compared with the conventional product, it was still not fully satisfactory, and the surface feeling of the obtained cast coated paper was not sufficient. Even when these methods are used, the non-cast surface feel, white paper glossiness, and printing glossiness are insufficient at the back-coated cast coated paper.
JP-A-4-146294 JP-A-9-268493

  In view of such circumstances, the problems of the present invention are high productivity, excellent cast surface texture, excellent white paper glossiness and printability, and non-cast surface texture and blank paper glossiness, printing. It is to provide a cast coated paper excellent in suitability and a method for producing the same.

  As a result of intensive studies to eliminate these disadvantages of various cast coated papers, the present inventors have succeeded in solving the problem by adding ingenuity to the prescription of the base paper and the non-cast surface, thereby completing the present invention. I let you.

  That is, the present invention provides a cast coated paper having a coating layer mainly composed of a pigment and an adhesive on both sides of a base paper, and finishing one side of the coating layer by performing a cast process. It contains an organic compound having an action of inhibiting interfiber bonding, and the coating layer on the opposite side of the cast processed surface contains 5 to 50 parts by weight of plastic pigment with respect to 100 parts by weight of the inorganic pigment, so that productivity is high. The cast coated paper with good cast surface feel like a mirror surface, excellent blank paper gloss and printability, and non-cast surface feel and blank paper gloss and printability can be obtained. is there. Further, the cast coating layer contains 5 to 50 parts by weight of a plastic pigment with respect to 100 parts by weight of the inorganic pigment, and 65% of the particles in the range of 0.4 to 4.2 μm on a volume basis as the inorganic pigment. By containing at least 50 parts by weight of kaolin having a particle size distribution contained above per 100 parts by weight of the inorganic pigment, the cast surface feeling, white paper glossiness and printing glossiness are improved, and in particular, the printing glossiness is improved. A coating liquid mainly composed of a pigment and an adhesive is applied to both sides of the base paper to form a coating layer, and after the wet coating layer is dried, one side of the coated paper is rewet In the manufacturing method of cast coated paper that is finished by applying a cast process that is plasticized and heated to a drum surface that has been plasticized and dried, the base paper contains an organic compound that has an action of inhibiting the interfiber binding of pulp, The coating layer on the opposite side of the processed surface contains 5 to 50 parts by weight of plastic pigment with respect to 100 parts by weight of the inorganic pigment. It was found that the surface of the cast surface was as good as a mirror surface, excellent in blank paper glossiness and printability, and excellent in the non-cast surface texture, blank paper glossiness and printability. In the present invention, the reason why the effect desired by the present invention is obtained is not necessarily clear, but is estimated as follows. Since the base paper containing an organic compound having an action of inhibiting the interfiber bonding of the pulp has many voids between the pulp fibers, the air permeability is improved. In general coating compositions, it is considered that the plastic pigment penetrates between the pigments in the coating layer to form voids, thereby improving the air permeability of the coating layer on the non-cast surface. Since the air permeability of the base paper and the coating layer on the non-cast surface is improved in this way, the cast drum temperature can be increased, the water can be removed smoothly during casting, and high-speed casting can be performed. As a result, it is considered that production can be performed with high efficiency. The feeling of the cast surface is improved by pressing the cast surface until the coated paper peels off from the cast drum, that is, when the moisture is sufficiently removed, but the air permeability of the base paper and the non-cast surface is improved. The improvement improves the dryness of the coated paper on the cast drum, so the cast surface feel is improved and a cast surface closer to a mirror is obtained, which is considered to improve the glossiness of the blank paper and the print glossiness. . In addition, by blending plastic pigment in the coating layer, the density of the coating layer is lowered to reduce the pigment filling rate in the coating layer. Coverability of the base paper with paint is improved. For this reason, it is considered that the surface feeling of the non-cast surface is improved, and accordingly, the blank paper glossiness and the print glossiness are also improved. On the other hand, by adding a plastic pigment in the coating layer of the cast surface, in addition to the effect of improving the air permeability, the plastic pigment is softened by the heat of the cast drum during the casting process, so that the coating layer becomes more plastic. It is considered that transferability on the cast drum surface is improved and a good cast surface is formed. Further, by using kaolin having a narrow particle size distribution in the coating layer on the cast surface, the coating layer is further reduced in the filling rate of the pigment particles, that is, the air permeability is improved. In addition to this, as described above, the coverage of the base paper with the paint is improved, and the glossiness of the white paper and the printing glossiness are improved. In addition, by smoothing the coated paper with a calendar before rewetting with the re-wetting liquid in the casting process, the non-cast surface glossiness and printing glossiness are further improved, and smoothness is also improved. As a result, a sheet having a better surface feeling, good dot reproducibility and excellent print quality can be obtained. Normally, in the calendar process, not only the non-cast surface but also the cast surface side is smoothed, so the adhesion of the coated paper to the cast drum when casting by the rewet method is improved, the feel of the cast surface, The glossiness of blank paper and printing glossiness are further improved.

  According to the present invention, cast coated paper having a high casting speed and excellent productivity can be produced. In addition, a cast coated paper having excellent cast surface texture, excellent blank paper glossiness and printability, and excellent non-cast surface texture, blank paper glossiness and printability can be obtained.

  In the present invention, a base paper containing a specific organic compound is provided with a coating layer mainly composed of a specific pigment and an adhesive on both sides of the base paper, and the coating layer on one side is heated in a wet state. The coated paper having a cast coating layer is obtained by press-contacting and drying on a mirror surface drum.

  The base paper of the present invention needs to contain an organic compound having an action of inhibiting the interfiber bonding of pulp. An organic compound having an action of inhibiting the interfiber bonding of pulp can be selected by the following test.

  An experimental orientation paper machine (Kumaya Riki Co., Ltd.) was prepared by using a pulp slurry in which 0.3 parts by weight of an organic compound to be tested was blended with 100 parts by weight of an absolutely dry pulp in a pulp composition constituting a target paper. Made), and the paper was made at a rotational speed of 900 rpm, and pressed and dried according to the method of JIS8209. In addition, about drying conditions, it processed at 50 degreeC and 1 hour with the ventilation drying machine. The test paper is left in the environment of 23 ° C. and relative humidity 50% for 24th time, and then the tensile strength is measured according to JIS P8113. The compound whose tensile strength decreases is an organic compound having an action of inhibiting the interfiber bonding of the present invention. Those having a very low decrease rate at this time have a low bulkiness effect, that is, an improvement effect of air permeability, and therefore it is necessary to add a large amount. Those with a large reduction rate have a bulky effect when added in a small amount. Accordingly, any organic chemicals whose tensile strength is reduced can be used, but those having a reduction rate of 0.3 to 30% are preferable, and those having 8 to 20% are particularly preferable. preferable.

  An organic compound (hereinafter abbreviated as a binding inhibitor) that inhibits the interfiber bonding of the pulp of the present invention is a compound having a hydrophobic group and a hydrophilic group, and has a tensile strength lowering effect in the above test. is there. Recently, a density reducing agent (or a bulking agent) marketed for paper making to increase the bulk of paper is suitable as a binding inhibitor of the present invention. For example, WO98 / 03730 and JP-A-11-200284. Examples thereof include compounds disclosed in JP-A No. 11-350380, JP-A No. 2003-96694, JP-A No. 2003-96695, and the like. Specifically, higher alcohol ethylene and / or propylene oxide adduct, polyhydric alcohol type nonionic surfactant, higher fatty acid ethylene oxide adduct, polyhydric alcohol and fatty acid ester compound, polyhydric alcohol and fatty acid Ethylene oxide adducts of these ester compounds, fatty acid polyamidoamines, fatty acid diamidoamines, fatty acid monoamides, or polyalkylenepolyamine / fatty acid / epichlorohydrin condensates can be used alone or in combination of two or more. can do. Preferred are polyhydric alcohol and fatty acid ester compounds, fatty acid diamide amines, fatty acid monoamides, polyalkylene polyamines / fatty acids / epichlorohydrin condensates and the like. Bulky chemicals on the market include BASF's Sulsol VL, Bayer's Bi-Volume P Liquid, Kao's KB-08T, 08W, KB110, 115, Sanki's React Pake, Japan PMC ), PT-205, Nippon Oil & Fats Co., Ltd. DZ2220, DU3605, Arakawa Chemical Co., Ltd. R21001, and these may be used alone or in combination of two or more. The cast coated paper of the present invention preferably contains 0.1 to 10 parts by weight of an interfiber binding inhibitor of pulp per 100 parts by weight of pulp in order to improve the air permeability of the base paper. It is preferable to contain 1.0 part by weight.

  In the base paper of the present invention, normal pulp, filler, etc. are blended in addition to the organic compound having an action of inhibiting the interfiber bonding of the pulp. In the present invention, the type of pulp blended into the base paper is not particularly limited. For example, hardwood kraft pulp (hereinafter referred to as LBKP), softwood kraft pulp (hereinafter referred to as NBKP), thermomechanical pulp, groundwood pulp, waste paper pulp and the like are used. Further, as fillers to be blended in the base paper, known fillers such as heavy calcium carbonate, light calcium carbonate, kaolin, clay, talc, hydrated silicic acid, white carbon, titanium oxide, synthetic resin filler, etc. can be used. . The amount of filler used is preferably 5% by weight or more per pulp weight, and is about 25% by weight. Further, if necessary, a sulfuric acid band, a sizing agent, a paper strength enhancer, a yield improver, a color pigment, a dye, an antifoaming agent and the like may be contained.

There is no particular limitation on the paper making method of the base paper, and any of the base papers made by acid paper making, neutral paper making, alkaline paper making using a long net machine including a top wire, a round net machine, etc. Of course, it is also possible to use a medium base paper containing mechanical pulp and a base paper containing recovered waste paper pulp. Furthermore, for the purpose of improving the surface treatment and size, a surface treatment agent mainly composed of a water-soluble polymer may be applied to the base paper. As the water-soluble polymer, those usually used as surface treating agents such as oxidized starch, hydroxyethyl etherified starch, enzyme-modified starch, polyacrylamide, polyvinyl alcohol, etc. can be used alone or a mixture thereof. . In addition to the water-soluble polymer, a paper strength enhancer for the purpose of improving water resistance and improving surface strength and an externally added sizing agent for the purpose of imparting size can be added to the surface treatment agent. The surface treatment agent can be applied by a coating machine such as a two roll size press coater, a gate roll coater, a blade metalling size press coater, a rod metalling size press coater, a film transfer type roll coater such as a shim sizer or a JF sizer. . Further, in the present invention, in addition to the application of the surface treatment agent, the base paper coated with a coating liquid containing a pigment and an adhesive used for general coated paper using the coating machine, or the surface A base paper coated with a blade coater, a roll coater, an enena knife coater or the like after the treatment agent is applied and dried can also be used. The coating amount in that case is preferably about ² to 30 g / m ² per side. Further, if necessary, the pre-coated base paper can be subjected to a smoothing process such as a machine calendar, a super calendar, or a soft calendar in advance.

Moreover, as a base paper used for this invention, although the basic weight used for a general coated paper can use the coated base paper about 30-200 g / m < ² >, Preferably a basic weight is 50-180 g / m < ² >. It is a coated base paper.

    In the present invention, it is necessary that the coating layer on the surface opposite to the cast processed surface contains a plastic pigment in an amount of 5 to 50 parts by weight, preferably 10 to 45 parts by weight, based on 100 parts by weight of the inorganic pigment. As the plastic pigment used in the present invention, a plastic pigment having a solid type, a hollow type, or a core / shell structure can be used alone or in combination of two or more as required. The compounding amount of the solid plastic pigment is preferably 10 to 50 parts by weight with respect to 100 parts by weight of the inorganic pigment, and the compounding amount of the hollow plastic pigment is preferably 5 to 25 parts by weight. As a constituent polymer component of the plastic pigment, a monomer such as styrene and / or methyl methacrylate is preferably used as a main component, and other monomers copolymerizable with these are used as necessary. Examples of the copolymerizable monomer include α-methylstyrene, olefinic aromatic monomers such as chlorostyrene and dimethylstyrene, methyl (meth) acrylate, ethyl (meth) acrylate, and butyl (meth) acrylate. There are monoolefin monomers such as 2-ethylhexyl (meth) acrylate, glycidyl (meth) acrylate and nitrile (meth) acrylate, and monomers such as vinyl acetate. If necessary, for example, olefinic unsaturated carboxylic acid monomers such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, hydroxyethyl, hydroxyethyl methacrylate, hydroxyacrylate Olefin unsaturated hydroxy monomers such as propyl, acrylamide, methacrylamide, N-methylol acrylamide, N-methoxymethyl acrylamide, N-methoxymethyl methacrylamide and the like olefin unsaturated amide monomers, such as divinylbenzene, Dimer vinyl monomers and the like can be used in at least one kind or a combination of two or more kinds. These monomers are exemplary, and other monomers that can be copolymerized can be used. The plastic pigment used in the present invention is preferably blended with an average particle diameter of 0.1 to 1.5 μm measured using a laser diffraction / scattering type particle size distribution measuring instrument that does not cause a decrease in surface strength. More preferably, 0.1 to 1.0 μm is blended.

  In the present invention, the cast coating layer to be cast is further improved in production efficiency by blending 5 to 50 parts by weight, preferably 20 to 45 parts by weight of plastic pigment with respect to 100 parts by weight of the inorganic pigment as a pigment. In addition, the cast surface feeling, the blank surface glossiness of the cast surface, and the print glossiness are improved. The compounding amount of the solid plastic pigment is preferably 10 to 50 parts by weight with respect to 100 parts by weight of the inorganic pigment, and the compounding amount of the hollow plastic pigment is preferably 5 to 25 parts by weight. The plastic pigment that can be blended in the cast coating layer can be the same as that blended in the coating layer on the opposite side of the cast surface. Further, in the present invention, as the pigment of the cast coating layer, kaolin having a particle size distribution containing 65% or more of particles in the range of 0.4 to 4.2 μm on a volume basis is 50 parts by weight per 100 parts by weight of the inorganic pigment. As described above, more preferably 60 parts by weight or more, and even more preferably 70 parts by weight or more improves the cast surface feeling, the blank glossiness of the cast surface, and the print glossiness.

  In the present invention, the coating layer on the cast-processed surface and the opposite surface has a kaolin, clay, delaminated clay, heavy carbonate other than the above conventionally used for coated paper in addition to the pigment. One or more inorganic pigments such as calcium, light calcium carbonate, talc, titanium dioxide, barium sulfate, calcium sulfate, zinc oxide, silicic acid, silicate, colloidal silica, and satin white can be selected and used as necessary.

  The adhesive used for the coated surface and the opposite coated layer of the present invention is not particularly limited, and is conventionally used for coated paper, styrene / butadiene, styrene / acrylic, Synthetic adhesives such as various copolymers such as ethylene / vinyl acetate, butadiene / methyl methacrylate, vinyl acetate / butyl acrylate, and polyvinyl alcohol, maleic anhydride copolymer, acrylic acid / methyl methacrylate copolymer , Casein, soy protein, synthetic protein proteins, oxidized starch, positive starch, urea phosphated starch, etherified starch such as hydroxyethyl etherified starch, starch such as dextrin, carboxyethylcellulose, hydroxyethylcellulose, hydroxymethylcellulose, etc. Usually such as cellulose derivatives Coating an adhesive one or more for paper suitably selected and used. These adhesives are used in an amount of about 5 to 50 parts by weight, more preferably about 5 to 30 parts by weight with respect to 100 parts by weight of the inorganic pigment.

  In addition to the above pigments and adhesives, the cast coating layer contains sodium chloride, ammonium chloride, zinc chloride, magnesium chloride, sodium sulfate, potassium sulfate, ammonium sulfate, zinc sulfate, magnesium sulfate, ammonium nitrate, and primary phosphoric acid. Sodium, ammonium phosphate, calcium phosphate, sodium polyphosphate, sodium hexametaphosphate, sodium formate, ammonium formate, sodium acetate, potassium acetate, sodium monochlorophosphate, sodium malonate, sodium tartrate, potassium tartrate, sodium citrate, potassium citrate, Ammonium and metal salts of inorganic and organic acids such as sodium lactate, sodium gluconate, sodium adipate, sodium dioctylsulfosuccinate, methylamine, diethanolamine, die Rentoriamin, can be appropriately used various additives such as diisopropylamine. Further, if necessary as an auxiliary agent, a dispersant, a thickener, a water retention agent, an antifoaming agent, a colorant, a mold release agent, a flow modifier, a water resistance agent, a preservative, a printability improver, etc. Various auxiliaries blended in the coating paper-needed coating composition are appropriately used.

As a method for applying the prepared cast surface coating composition and the cast surface opposite surface coating composition to the base paper, a two-roll size press coater, a gate roll coater, a blade metering size press coater, a rod In addition to film transfer type roll coaters such as metal ring size press coaters, shim sizers, and JF sizers, blade metal ring coaters such as flooded nip / blade coaters, short dwell time application type, and validd well time type fountain coaters, Instead, it can be applied with a rod metering coater using a grooved rod, a plain rod, etc., or a known coater such as an air knife coater, curtain coater, die coater, spray coater, etc. Blade metering coater to obtain a cast coated paper is blank surface feel and excellent high or an air knife coater, or a curtain coater, is preferred. Coating amount is preferably 5 to 30 g / m ² on one surface to the opposite surface of both of the cast working surface and cast coated surface, and more preferably from 10 to 25 g / m ^2. After coating, the coating layer is once dried, and the rewetting method in which the coating layer is re-wet with a re-wetting solution and cast finish can be used to improve not only the quality but also the operability. As a method for drying the wet coating layer, various types of dryers such as a steam heating cylinder, a hot air air dryer using gas or gas combustion gas heated hot air, a gas heater dryer, an electric heater dryer, an infrared heater dryer, etc. are used alone or in combination. Used in. The degree of drying of the coated paper varies depending on the type of the base paper and the type of the coating composition, but generally the paper moisture is in the range of 1 to 10%, and is preferably dried in the range of about 2 to 7%. In the present invention, the dried coating layer may be cast-finished by the rewet method as it is, but it is preferable to perform surface treatment for improving the cast surface feeling, white paper glossiness, printing glossiness, smoothness and the like. As a surface treatment method, a super calender using a cotton roll as an elastic roll or a soft nip calender using a synthetic resin roll as an elastic roll can be used. Moreover, about the metal roll, the mat roll which roughened the surface as needed other than the plain roll which smoothed the surface can be used. The surface treatment temperature is preferably in the range of 40 to 200 ° C, but more preferably in the range of 60 to 160 ° C. By these surface treatments, the blank paper glossiness (75 °) on the surface opposite to the cast surface after casting is set to 65% or more, so that not only the cast surface but also both surfaces have good surface feeling and excellent glossiness. A cast coated paper is obtained.

  In the present invention, in the casting process in which high gloss is obtained by pressure contact with the heated mirror drum, the effect is particularly prominent under the condition that the temperature of the mirror drum is 100 ° C. or higher.

  The rewetting liquid is not particularly limited. For example, a release agent such as polyethylene emulsion, fatty acid soap, calcium stearate, microcrystalline wax, surfactant, and funnel oil is about 0.01 to 3% by weight. Usual rewetting liquids such as aqueous solutions and emulsions are used. It is of course possible to use a phosphate such as alkali or sodium hexametaphosphate, urea, an organic acid or the like in order to promote plasticization of the dry coating layer. Furthermore, various adjuvants, such as an antifoaming agent, a water-resistant agent, a preservative, and a printability improver, which are blended in a normal coating paper-needed coating composition can be used as appropriate.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples and comparative examples of the present invention, but the present invention is not limited to these. In addition, unless otherwise indicated, the part and% in an example show a weight part and weight%, respectively. The selected cast coated paper was tested based on the following evaluation method. Also, the cast surface is referred to as “cast surface”, and the surface opposite to the cast surface is referred to as “coat surface”.
<Evaluation method>
(Volume Particle Size Distribution Measurement of Pigment) Using a laser diffraction / scattering particle size distribution analyzer (Malvern Co., Ltd., equipment name: Mastersizer S), the particle volume particle size distribution is measured, and the particle size is 50%. The average particle size was taken.
(Weight) According to JIS P 8124: 1998.
(Density) According to JIS P 8118: 1998.
(Cast surface feeling) According to JIS K 7105, using Suga Test Instruments Co., Ltd. image clarity measuring instrument: ICM-1T, it measured on the conditions of an incident light angle of 60 degrees and a comb width of 2 mm.

(Blank Gloss) According to JIS P 8142: 1998. In addition, regarding the cast surface, only the measurement part was changed to 20 ° gloss measurement.
(Print gloss) Using RI-II type printing tester, printing is performed using 0.30cc of Toyo Ink Manufacturing Co., Ltd. sheet-fed process ink (trade name: TK High Echo Red MZ). The surface of the printed material was measured according to JIS P 8142: 1998.
(Coat surface feeling) Sensory evaluation was performed on the surface of the coat surface by a monitor of 10 people. ◎… Excellent, ○… Excellent, △… Slightly inferior, ×… Inferior (casting operability) When cast coated paper is produced according to the examples, sticking of cast coated paper to cast drum or cast coating Judgment was made based on whether or not drum picking occurred on the surface of the cast paper.
○… No sticking to the cast drum or drum pick on the cast paper surface of the coated paper.
Δ: Sticking to the cast drum or drum picking occurs on the surface of the coated paper cast surface.
X: Sticking to the cast drum or drum picking occurs on the surface of the coated paper cast surface, making it impossible to produce cast paper with good quality.
[Selection of Binding Inhibitor] 30 parts of NBKP and 70 parts of refiner ground pulp (RGP) were made into a 1% slurry, and 0.3 parts of the following compound was added to and mixed with the slurry to prepare a stock. This stock was made with an experimental orientation paper machine manufactured by Kumagai Riki Co., Ltd. at a rotational speed of 900 rpm, and pressed and dried according to the method of JIS8209. In addition, about drying conditions, it processed at 50 degreeC and 1 hour with the ventilation dryer, and the test paper for a test was obtained. The test paper was allowed to stand at a temperature of 23 ° C. and a relative humidity of 50% for 24 hours, and then the tensile strength was measured according to JIS P8113. The measurement results are shown in Table 1.

From the above test, the tensile strength reduction rate is preferably 6% or more, and those showing a reduction rate of 10% or more are particularly suitable for the present invention.
Next, cast coated paper was prepared and evaluated for one type of KB115 manufactured by Kao Co., Ltd., which showed good binding inhibition properties.
[Example 1]
A base paper with a basis weight of 116 g / m ² containing 100 parts of chemical pulp as paper pulp, 8 parts of light calcium carbonate as filler, and 0.6 parts of Kao Corporation KB-110 as a binding inhibitor between pulp fibers , Brazilian kaolin (trade name: manufactured by Capim DG / Imeris, volume distribution particle size 0.4 to 4.2 μm: 71.7%), 70 parts of light calcium carbonate (trade name: TP-123CS / made by Okutama Kogyo) ) 30 parts of a solid plastic pigment (trade name: V-1004 / manufactured by Nippon Zeon, average particle size 0.32 μm, glass transition temperature 85 ° C.) 30 parts of pigment, 0.1% sodium polyacrylate as a dispersant Part, 13.5 parts of styrene-butadiene copolymer latex (hereinafter referred to as SBR) and 3.5 parts of starch are added as binder, and water is further added to a solid content concentration of 60%. Coating a blade coater so coating amount becomes 12 g / m ² for stabilizing the casting surface coating solution, and dried. Following this, 80 parts of fine kaolin (manufactured by Amazon Plus / Kadam, volume distribution particle size 0.4 to 4.2 μm: 42.0%) as a pigment, heavy calcium carbonate (trade name: FMT90 / manufactured by Pimatech) 20 parts by volume distribution particle size 0.4 to 4.2 μm: 65.0%), solid plastic pigment (trade name: V-1004 / manufactured by Nippon Zeon, average particle size 0.32 μm, glass transition temperature 85 ° C.) 20 0.1 parts of poly (sodium acrylate) as a dispersant, 13.5 parts of styrene-butadiene copolymer latex (hereinafter referred to as SBR) and 3.5 parts of starch as a binder are added to the pigment composed of parts, and water is further added. The coating surface coating liquid adjusted to a solid content concentration of 60% was coated with a blade coater and dried so that the coating amount was 12 g / m ² . Thereafter, surface treatment was performed using a super calendar.

After re-wetting the surface of the coating layer of the coated paper thus obtained with a rewetting liquid (sodium hexametaphosphate 0.5% concentration), it is passed through a press nip formed by a forming roll and a cast drum. The paper was pressed, pressed onto a cast drum having a speed of 150 m / min and a surface temperature of 115 ° C., dried, and then released from the cast drum by strip-off all to obtain a cast coated paper.
[Example 2]
The pigment of the paint for the cast surface is 70 parts of fine kaolin (manufactured by Amazon Plus / Caddam, volume distribution particle size 0.4 to 4.2 μm: 42.0%), light calcium carbonate (trade name: TP-123CS / Okutama Industry) Casted in the same manner as in Example 1 except that 30 parts, solid plastic pigment (trade name: V-1004 / manufactured by Nippon Zeon, average particle size 0.32 μm, glass transition temperature 85 ° C.) 30 parts Coated paper was obtained.
[Example 3]
The coating surface pigment is made of 80 parts fine kaolin (made by Amazon Plus / Kaddam, volume distribution particle size 0.4 to 4.2 μm: 42.0%), heavy calcium carbonate (trade name: FMT97 / Pimatec) , Volume distribution particle size 0.4 to 4.2 μm: 65.0%) 20 parts, solid plastic pigment (trade name: V-1004 / manufactured by Nippon Zeon, average particle size 0.32 μm, glass transition temperature 85 ° C.) A cast coated paper was obtained in the same manner as in Example 1 except that the amount was 10 parts.
[Comparative Example 1]
A cast coated paper was obtained in the same manner as in Example 1 except that no binding inhibitor was added to the base paper.
[Comparative Example 2]
A dull-coated paper was obtained in the same manner as in Example 1 except that no plastic pigment was blended in the pigment of the coating paint.

  For cast coated paper manufactured under the above conditions, basis weight, paper thickness, density, cast surface cast feel, blank paper gloss (20 °), print gloss, coated surface feel, blank paper gloss, printing Glossiness was evaluated. Casting operability was also evaluated and the results are summarized in Table 2.

表２から明らかなように、実施例で得られるキャスト塗工紙は生産性が高く、かつキャスト面の面感が鏡面のように良好で、かつ白紙光沢度、印刷適性に優れ、かつ非キャスト面の面感および白紙光沢度、印刷適性が優れるキャスト塗工紙であることが明らかである。

As is apparent from Table 2, the cast coated paper obtained in the examples has high productivity, the cast surface has a good mirror surface, and is excellent in white paper glossiness, printability, and non-cast. It is clear that this is a cast-coated paper having excellent surface texture, white paper glossiness, and printability.

Claims (6)

  In cast coated paper that has a coating layer mainly composed of a pigment and an adhesive on both sides of the base paper and is finished by casting one side of the coating layer, the base paper inhibits the fiber-to-fiber bonding of the pulp. A cast coated paper comprising an organic compound having an action, and the coating layer on the opposite side of the cast surface contains 5 to 50 parts by weight of a plastic pigment with respect to 100 parts by weight of the inorganic pigment.   2. The cast coated paper according to claim 1, wherein the cast coating layer to be cast contains 5 to 50 parts by weight of a plastic pigment with respect to 100 parts by weight of the inorganic pigment.   The tensile strength (measured according to JIS P 8113) of the base paper in which the organic compound having an action of inhibiting the interfiber bonding of the pulp is combined with 0.3 part by weight of the organic compound with respect to 100 parts by weight of the absolutely dry pulp The cast coated paper according to claim 1 or 2, wherein the cast coated paper is an organic compound having a reduction rate of 5 to 30% with respect to the tensile strength of the base paper not containing the organic compound.   The cast coating layer subjected to the above-mentioned cast processing contains at least 50 parts by weight of kaolin having a particle size distribution containing 65% or more of particles in the range of 0.4 to 4.2 μm on a volume basis per 100 parts by weight of the inorganic pigment. The cast coated paper according to any one of claims 1 to 3, wherein: A coating liquid mainly composed of a pigment and an adhesive is applied to both sides of the base paper to form a coating layer, and after the wet coating layer is dried, one side of the coated paper is rewet In the manufacturing method of cast coated paper, which is finished by applying a cast process that is plasticized and heated to a mirror drum surface that is plasticized and dried, the base paper contains an organic compound that has an action of inhibiting the interfiber bonding of pulp, The method for producing cast coated paper, wherein the coating layer on the opposite side of the cast processed surface contains 5 to 50 parts by weight of a plastic pigment with respect to 100 parts by weight of the inorganic pigment. 6. The method for producing cast coated paper according to claim 5, wherein one side of the coated paper on which the coated layer is formed is surface-treated before the casting.