JP2007077536A - Coated paper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coated paper stably running even in a copying machine or printer with increased speed. <P>SOLUTION: The coated paper comprises a base paper and at least one coated layer which comprises a pigment and an adhesive as principal component, formed on at least one of surfaces of the base material, wherein the outermost surface layer of the coated layer contains rough particles and the rough particles are the surface treated particles the surface of which are coated with lubricants. The preferable lubricants are at least one selected from an aliphatic hydrocarbon based lubricant, a higher aliphatic alcohol based lubricant, a higher fatty acid based lubricant, a higher fatty acid amide based lubricant, a higher fatty acid metal salt based lubricant or a higher fatty acid ester based lubricant. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a coated paper suitable for a cut sheet used in an electrophotographic copying machine, a printer, and the like, and particularly relates to a coated paper excellent in runnability on a high-speed machine.

  In recent years, electrophotographic copying machines and printers have become more colorized, faster, and higher in image quality. Especially, in the field of on-demand publications, it is possible to handle more easily and smaller copies. For this reason, there has been a noticeable movement to create publications that have been obtained by printing with color copiers and color printers.

High white glossy coated paper used for offset printing in the commercial printing field usually uses various coaters and uses a coating liquid mainly composed of a pigment having an average particle size of 2 μm or less as a base material. After applying 10g / m ² or more per side and smoothing the surface by calendering, conventional high-quality paper is used to form vivid images in the field of electrophotographic copying machines and printers. In many cases, coated paper is used instead of PPC paper and printer paper.

  However, the high white glossy coated paper used for normal printing has a high coefficient of friction between the sheets because it is smooth and easy to adhere to each other compared to the high quality paper, and it is one by one from the top of the accumulated paper. When feeding into the copying machine, two or more sheets are fed at a time, so-called double feeding, and so-called misfeeding that does not feed into the copying machine tends to occur.

  Up to now, as a method for improving the running property of the paper, for example, a method of adjusting the difference between the inter-layer friction coefficient and the inter-layer friction coefficient of the deposited copying paper to 0.03 or less by, for example, applying a lubricant to the surface of the paper ( For example, refer to Patent Document 1), a method of applying an alkyl ketene dimer as a friction coefficient lowering agent to reduce the frictional resistance between transfer papers (for example, refer to Patent Document 2), Wangken smoothness of coated paper (JTAPPI No. 5) in 60 to 300 seconds, the method of adjusting the air permeability in the range of 10 to 90 seconds (for example, see Patent Document 3), an aqueous silicone oil-containing coating liquid having a reactive substituent A method of impregnating both sides of a base paper (for example, see Patent Document 4), a method for suppressing the air permeability and swelling of paper (for example, see Patent Documents 5 and 6), and spherical coarse particles having an average particle diameter of 3 to 50 μm And mainly lubricants, pigments and adhesives A method (for example, refer to Patent Document 7) and the like to be included in the coating layer as a component has been proposed, but none of them is sufficient as a countermeasure, and in recent years, as the speed of copying machines and printers has increased, Even paper that does not cause problems such as double feeding and misfeeding in conventional machines is becoming a problem.

JP 58-95746 A JP-A-3-220560 JP-A-8-171226 JP-A-4-303847 Japanese Patent Laid-Open No. 11-160906 Japanese Patent Laid-Open No. 11-174713 Japanese Patent Application No. 2003-145417

  The present invention aims to provide a coated paper that can solve the problem of running of cut paper that the conventional coated paper has, and that can be stably run even by high-speed copying machines and printers. .

  As a result of intensive investigations to solve the above problems, the present inventors blended surface-treated particles that have been coated with a lubricant in advance, rather than a conventional coated paper formulation that contains a lubricant in the coating layer. As a result, it was found that the problem can be solved, and the present invention has been completed.

(1) In a coated paper comprising a paper base material and a coating layer mainly comprising a pigment and an adhesive on at least one surface thereof, the coating layer contains coarse particles, and Coated paper, wherein the coarse particles are surface-treated particles whose surfaces are coated with a lubricant.
(2) Coated paper comprising a paper base material and a plurality of coating layers mainly composed of a pigment and an adhesive on at least one surface thereof, and coarse particles in the outermost surface layer of the coating layer. A coated paper characterized in that the coarse particles are surface-treated particles whose surface is coated with a lubricant.
(3) The lubricant comprises an aliphatic hydrocarbon lubricant, a higher aliphatic alcohol lubricant, a higher fatty acid lubricant, a higher fatty acid amide lubricant, a higher fatty acid metal salt lubricant, a higher fatty acid ester lubricant, and two or more thereof. The coated paper according to (1) or (2), which is at least one selected from the combined lubricants used in combination.
(4) The coated paper according to (1) or (2), wherein the average particle diameter of the surface-treated particles is 3.0 to 50.0 μm.
(5) The coated paper according to any one of (1) to (4), wherein the amount of treatment with the lubricant used for the surface coating is 1 to 30 parts by mass with respect to 100 parts by mass of the coarse particles.
(6) The coated paper according to any one of (1) to (5), wherein the coarse particles are spherical calcium carbonate.
(7) The coated paper according to (1) or (2), wherein the surface coating is performed using an emulsion lubricant.
(8) The coated paper according to any one of (1) to (7), wherein the lubricant is an aliphatic hydrocarbon lubricant.
(9) The coated paper according to (8), wherein the aliphatic hydrocarbon lubricant is polyethylene wax.

  According to the present invention, coated paper capable of stable running with a high-speed copying machine or printer can be obtained.

  Patent Document 7 describes that runnability and the like are improved by blending spherical coarse particles and a lubricant in the coating layer, but a method of blending surface-treated particles previously coated with a lubricant is described. It has not been. In the present invention, as a result of coating the surface of the coarse particles with a lubricant, the part protruding from the surface of the coating layer is completely covered with the lubricant, and the sliding effect of the lubricant appears more remarkably, reducing the friction coefficient between papers. However, it seems that stable running is possible even with high-speed machines.

  The coated paper of the present invention is one in which one or more coating layers mainly composed of a pigment and an adhesive are provided on one or both sides of a paper substrate, and the surface is coated with a lubricant in the coating solution. It is a blend of treated particles. The lubricant used in the present invention is not particularly limited, and examples thereof include aliphatic hydrocarbon lubricants, higher aliphatic alcohol lubricants, higher fatty acid lubricants, higher fatty acid amide lubricants, and higher fatty acid metal salt systems. Examples thereof include lubricants, higher fatty acid ester lubricants, and composite lubricants using a combination of two or more thereof. More specifically, aliphatic hydrocarbon lubricants: C16 or higher liquid paraffin, microcrystalline wax, natural paraffin, synthetic paraffin, polyolefin wax and partial oxides thereof, or higher aliphatic alcohols such as fluoride and chloride. C16 or higher fatty alcohol, higher fatty acid lubricant: C16 or higher fatty acid, higher fatty acid amide lubricant: C16 or higher fatty acid amide and bisamide, higher fatty acid metal salt lubricant: C10 or higher fatty acid Metal salts, higher fatty acid ester lubricants: higher fatty acid esters of monohydric alcohols, higher fatty acid (partial) esters of polyhydric alcohols. Among these, aliphatic hydrocarbon lubricants exhibit particularly good effects on running performance, and polyethylene wax is particularly preferable.

  Examples of coarse particles used in the present invention include inorganic and organic pigments commonly used in the field of coated paper. Examples of inorganic pigments include heavy calcium carbonate, light calcium carbonate, kaolin, and baking. Kaolin, structural kaolin, deramikaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, alumina, magnesium carbonate, magnesium oxide, silica, magnesium aluminosilicate, calcium silicate, white carbon, bentonite, zeolite, sericite, Examples include mineral substances such as smectite. Examples of organic pigments include polydienes such as polyisoprene, polyneoprene, and polybutadiene, polyalkenes such as polybutene, polyisobutylene, polypropylene, and polyethylene, vinyl halides, vinyl acetate, styrene, (meth) acrylic acid, and (meth). Vinyl polymers and copolymers such as acrylic ester, (meth) acrylamide, methyl vinyl ether, polyurethane resins, polyester resins, polyamide resins, urea resins, melamine resins, benzoguanamine resins, vinylidene chloride Examples thereof include a solid type such as a resin, a hollow type, or a through-hole type particle. In the present invention, one or more of these are appropriately selected and used.

  Among these, spherical calcium carbonate is preferable in terms of performance and price. Examples of the method for producing the spherical calcium carbonate include a method of reacting an aqueous solution of calcium carbonate with an aqueous solution of calcium chloride, a method of reacting a calcium hydroxide salt and carbonate in the presence of a divalent cation other than calcium, As described in Japanese Patent No. 16417, a method for producing a vaterite-type spherical calcium carbonate by reacting calcium chloride and hydrogen carbonate in the presence of a phosphoric acid compound is described in Japanese Patent Laid-Open No. 4-4247. Thus, a method of producing spherical calcium carbonate by introducing carbon dioxide gas into a calcium hydroxide slurry in the presence of an additive can be exemplified.

  The average particle diameter of the coarse particles used in the present invention is preferably in the range of 3.0 to 50.0 μm, particularly preferably in the range of 3.0 to 30.0 μm. When the average particle diameter is less than 3.0 μm, the effect of improving the running property is small, and when it exceeds 50.0 μm, the gloss of the white paper and the feeling of touch are liable to be inferior. The amount of treatment with the lubricant used for coating is preferably 1 to 30 parts by mass with respect to 100 parts by mass of coarse particles. When the processing amount is less than 1 part by mass, the effect of improving the running property is small, and when it exceeds 30 parts by mass, the particles are likely to be fused and the paper is inferior to the touch.

  The method for coating the surface of the pigment with the lubricant in the present invention is not particularly limited. For example, water or an organic solvent-based mixed dispersion of the lubricant and the pigment is heated with stirring, and water or A method of forming a lubricant film on the pigment surface by removing the organic solvent, spray-drying water or an organic solvent mixed dispersion of the lubricant and the pigment, and removing the water or the organic solvent to remove the lubricant on the pigment surface. A method of forming a film, water or an organic solvent-based lubricant solution or dispersion is dropped or sprayed onto a powder pigment under stirring, and the water or organic solvent is removed during or after the process to form a pigment surface. Examples include a method of forming a lubricant film, a method of stirring and mixing a powdery lubricant and a pigment together, and then melting the lubricant by heating or heat by stirring to form a lubricant film on the pigment surface. Rukoto can be.

  As the most preferred coarse particles in the present invention, spherical calcium carbonate is used. Both aqueous lubricant dispersion and spherical calcium carbonate dispersion are both stirred and mixed using a high-speed stirrer, and then this system is used. It was obtained by the method of forming a lubricant film on the surface of spherical calcium carbonate by removing water from the surface. In addition, as this lubricant dispersion, the thing of a 10-50 mass% density | concentration is used normally, and a 20-60 mass% density | concentration is normally used as a spherical calcium carbonate dispersion liquid. The lubricant-coated spherical calcium carbonate, which is the surface-treated particles thus obtained, is particularly excellent in the effect of improving running performance and is preferable.

  The surface-treated particles in the present invention are usually blended in the range of 0.5 to 10% by mass based on the total solid content of the coating liquid.

  In the present invention, in addition to the surface-treated particles, a pigment not coated with a lubricant is blended in the coating liquid. Examples of such pigments include the above-mentioned inorganic and organic pigments used for coating, and one or two or more are appropriately selected and used. The particle diameter of the pigment is not particularly limited, but a pigment in the range of 0.1 to 5 μm is usually used. The pigment is usually blended in the range of 60 to 90% by mass with respect to the total solid content of the coating liquid. Among the pigments, a system in which an organic pigment having at least one peak in a range of Tg of 20 to 150 ° C. is blended in a range of 5 to 60% by mass with respect to the total solid content of the coating liquid is disclosed in JP-A-2005-36378. As described in the publication, good crack formation is observed in the coating layer, air permeability is good, and blisters are hardly generated, which is particularly preferable. In the case of the crack, since the crack is not blocked and good air permeability is maintained even if gloss treatment such as super calender is performed, the blank paper glossiness at an incident / light reception angle of 75 degrees based on JIS Z 8741 is 45 to 85. % Is effective as a means of obtaining coated paper. Coated paper with good results for blisters is JAPAN TAPPI paper pulp test method no. Oken type air permeability based on 5-2: 2000 is 8000 seconds or less. Among them, those having a time of 5000 seconds or less are preferable, and those having a time of 2000 seconds or less are more preferable.

  In addition, a system in which a hollow organic pigment is blended as the pigment can further improve the air permeability while maintaining the glossiness at a high level. Since the system using hollow organic particles is easily glossy by a gloss treatment such as a super calender, and can be processed at a lower pressure, the air permeability can be kept high. The blending amount of the hollow organic pigment is preferably 20% by mass or less based on the total solid content of the coating liquid. When it exceeds 20% by mass, an opacity lowering phenomenon called calender burn or blacking tends to occur in a gloss imparting process such as a super calender.

  Examples of the adhesive used in the present invention include various copolymers such as styrene-butadiene, styrene-acryl, ethylene-vinyl acetate, methyl methacrylate-butadiene, vinyl acetate-butyl acrylate, and polyvinyl alcohol. , Synthetic adhesives such as maleic anhydride copolymer, acrylic acid-methyl methacrylate copolymer, oxidized starch, enzyme-modified starch, esterified starch, etherified starch, cationic starch, amphoteric starch, thermochemically modified starch And natural adhesives such as gelatin and casein. One type or two or more types of adhesives can be appropriately selected and used as necessary. The adhesive is usually blended in the range of 0.5 to 40% by mass based on the total solid content of the coating liquid.

  In the coating liquid, in addition to the surface-treated particles, pigments and adhesives, various auxiliary agents such as surfactants, pH regulators, viscosity modifiers, water retention agents, softeners, gloss-imparting agents, waxes, dispersants. , Flow modifier, antistatic agent, stabilizer, antistatic agent, cross-linking agent, sizing agent, fluorescent brightener, colorant, ultraviolet absorber, antifoaming agent, water-resistant agent, plasticizer, preservative, fragrance It is possible to mix | blend etc. suitably as needed.

  The pulp used as the main raw material of the paper base material used in the present invention is not particularly limited with respect to the production method, type, etc. Chemical pulp such as KP and SP, mechanical pulp such as SGP, RGP, BCTMP, and CTMP, , Chlorine-free pulp such as ECF pulp and TCF pulp, waste paper pulp such as deinked pulp, or non-wood pulp such as kenaf, bagasse, bamboo, straw, hemp, etc., organic materials such as polyamide fiber, polyester fiber, polynosic fiber Synthetic fibers, and also inorganic fibers such as glass fibers, ceramic fibers, and carbon fibers can be used.

  In addition, a filler can be blended in the stock used for paper formation, if necessary. The filler is not particularly limited, but various pigments generally used for fine paper, such as kaolin, calcined kaolin, calcium carbonate, calcium sulfate, barium sulfate, titanium dioxide, talc, zinc oxide, alumina, magnesium carbonate, Mineral pigments such as magnesium oxide, silica, white carbon, bentonite, zeolite, sericite, smectite, polystyrene resin, urea resin, melamine resin, acrylic resin, vinylidene chloride resin and their solid type, Examples thereof include organic pigments that are fine hollow type and through-hole type particles.

  In addition to the above pulp fibers and fillers, various anionic, nonionic, cationic or amphoteric yield improvers, drainage improvers, paper strength enhancers, fixing agents are used in the paper stock. Various paper-making internal additives such as sizing agent and internal additive can be appropriately selected and used as necessary. Furthermore, internal additives for papermaking such as dyes, fluorescent brighteners, pH adjusters, antifoaming agents, pitch control agents, slime control agents and the like can be appropriately added depending on the use of the paper.

  The paper making method of the paper base is not particularly limited, and includes, for example, an acidic paper making method in which the paper making pH is around 4.5, and a neutral sizing agent and / or an alkaline filler such as calcium carbonate as a main component. All papermaking methods can be used, such as a weakly acidic neutral papermaking method with a pH of about 9 to a weakly alkaline neutral papermaking method with a papermaking pH of about 9, such as long net paper machine, twin wire paper machine, round net paper machine, Yankee paper machine, Commonly used paper machines such as inclined wire paper machines can be used as appropriate.

  In order to obtain coated paper with good air permeability that hardly generates blisters, it is impossible to use a paper substrate having extremely inferior air permeability. The paper base material in the present invention is JAPAN TAPPI paper pulp test method no. The air permeability based on 5-2: 2000 is preferably 30 seconds or less, particularly preferably 20 seconds or less.

Although the basic weight of the paper base material used for this invention is not specifically limited, The thing of the range of 40-300 g / m < ² > is used normally.

The coating amount of the coating solution to the paper substrate is not particularly limited, a 2~25g / m ² at normal per one side solid content, preferably 5 to 20 g / m ^2. When the coating amount is less than ² g / m ² , it is difficult to obtain a product with good white paper gloss. On the other hand, when it exceeds 25 g / m ² , the coating speed does not increase and the cost may increase.

  For the coating, generally known coating apparatuses such as blade coaters, air knife coaters, roll coaters, reverse roll coaters, bar coaters, curtain coaters, slot die coaters, gravure coaters, Champlex coaters, brush coaters, slide bead coaters, two rolls. Alternatively, a metering blade type size press coater, a bill blade coater, a short dwell coater, a gate roll coater, or the like is appropriately used.

  The coating layer is formed on one side or both sides of the paper substrate, and two or more layers can be laminated on the same side. When performing double-sided coating and multi-layer coating, each coating liquid need not have the same composition or the same coating amount, and is determined according to a desired quality level. In the case of lamination, the coating liquid that forms the outermost surface layer is a coating liquid that contains the surface-treated particles, and the coating liquid that forms the lower layer contains the surface-treated particles. Also good.

  In addition, a synthetic resin layer, an antistatic layer, or the like can be provided on the back surface of the single-side coated product for the purpose of preventing curling or imparting printability. Further, post-processing such as adhesion, heat sensitivity, magnetism, flame retardancy, heat resistance, water resistance, oil resistance, anti-slip, thermal transfer receiving layer, ink jet receiving layer and the like can be performed for the purpose of imparting other application suitability.

  The coated paper thus obtained is subjected to a smoothing treatment as necessary. The smoothing process is performed on-machine or off-machine using a smoothing processing apparatus such as a normal super calendar, gloss calendar, or soft calendar. A preferable white paper gloss is in the range of 45 to 85%, more preferably in the range of 55 to 85% with a white paper gloss of 75 degrees of incident / light receiving angle based on JIS Z 8741.

  The coated paper of the present invention is finished by adjusting so that the water content is in the range of 3 to 10% by mass, preferably in the range of 4 to 8% by mass.

  The coated paper obtained by the present invention can be used as normal printing paper such as offset printing in addition to electrophotographic paper.

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

Example 1
[Preparation of paper substrate]
To a pulp slurry of 90 parts of LBKP (freeness (CSF) = 450 ml) and 10 parts of NBKP (freeness (CSF) = 450 ml), light calcium carbonate (PC: manufactured by Shiroishi Calcium Co., Ltd.) was added to 5 parts. Paper is made on a long paper machine using a stock to which 1.5 parts of starch, 100 parts of alkenyl succinic anhydride and 0.6 part of sulfuric acid band are added per 100 parts of pulp, and starch is applied during the paper making process. Paper with a weight of 60 g / m ² is applied and dried with a size press so that the work weight is 1 g / m ^2, and smoothed with a machine calendar so that the Beck smoothness is 30 seconds. A substrate was obtained.

[Preparation of surface-treated particles]
Ninety parts of spherical calcium carbonate (trade name: TP-S010, manufactured by Okutama Kogyo Co., Ltd.) having an average particle diameter of 10 μm is placed in a container, and a polyethylene wax emulsion (trade name: Nopcoat PEM17, manufactured by San Nopco Co., Ltd.) is added at a solid content of 10 with stirring. After partial spraying, heating was performed under reduced pressure to remove moisture, and calcium carbonate whose surface was coated with a lubricant as surface-treated particles was obtained.

[Preparation of coating solution]
Water and a dispersing agent (trade name: Aron A-9, manufactured by Toagosei Co., Ltd.) 0.01 part are added to 5 parts of Miragus 91 (component: Kaolin, manufactured by Engelhard), and dispersed with a Coreless disperser. A kaolin dispersion with a content of 72% was obtained. To this dispersion, 65 parts of FMT-97 (component; heavy calcium carbonate, manufactured by Pimatech) with a solid content of 75% was added as a solid content to prepare a pigment slurry. To this pigment slurry, 0.3 parts of carboxymethyl cellulose (trade name; AG Gum HE No. 2, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), synthetic resin pigment POT-7092 (Tg; 35 ° C., manufactured by Nippon Zeon Co., Ltd.), 10 parts, 20 parts of resin pigment S2577A (Tg; 75 ° C., manufactured by JSR) and 3 parts of the surface-treated particles were added and stirred, and water was further added to prepare a coating liquid having a solid content concentration of 55%.

[Formation of coating layer]
The coating solution was applied to both sides of the paper base material at a coating speed of 500 m / min and a hot air temperature of 160 ° C. using a blade coater so that the dry weight per side was 12 g / m ² . Then, it processed with the pressurization nip comprised by the metal roll and the elastic roll, and obtained the coated paper of 45% of blank paper glossiness, and a basic weight of 84 g / m < ² >.

Example 2
A coated paper was obtained in the same manner as in Example 1 except that the same amount of higher fatty acid emulsion was used instead of the polyethylene wax emulsion when preparing the surface-treated particles.

Example 3
A coated paper was obtained in the same manner as in Example 1 except that the same amount of higher fatty acid amide emulsion was used instead of the polyethylene wax emulsion when preparing the surface-treated particles.

Example 4
A coated paper was obtained in the same manner as in Example 1 except that the same amount of higher fatty acid metal salt emulsion was used instead of the polyethylene wax emulsion when preparing the surface-treated particles.

Example 5
When the surface-treated particles were prepared, the same procedure was carried out except that the same amount of spherical calcium carbonate having an average particle diameter of 4 μm was used instead of spherical calcium carbonate having an average particle diameter of 10 μm (trade name: TP-S010, manufactured by Okutama Kogyo Co., Ltd.). Coated paper was obtained in the same manner as in Example 1.

Example 6
When preparing the surface-treated particles, the same procedure was performed except that the same amount of spherical calcium carbonate having an average particle diameter of 30 μm was used instead of spherical calcium carbonate having an average particle diameter of 10 μm (trade name: TP-S010, manufactured by Okutama Kogyo Co., Ltd.). Coated paper was obtained in the same manner as in Example 1.

Example 7
When preparing the surface-treated particles, polystyrene spherical particles having an average particle diameter of 10 μm (trade name: SGP-50C, Soken) instead of spherical calcium carbonate having an average particle diameter of 10 μm (trade name: TP-S010, manufactured by Okutama Kogyo Co., Ltd.) Coated paper was obtained in the same manner as in Example 1 except that the same amount was used.

Example 8
When preparing the surface-treated particles, polystyrene spherical particles having an average particle diameter of 55 μm (trade name: SGP-150C, Soken) instead of spherical calcium carbonate having an average particle diameter of 10 μm (trade name: TP-S010, manufactured by Okutama Kogyo Co., Ltd.) Coated paper was obtained in the same manner as in Example 1 except that the same amount was used.

Example 9
During the preparation of the surface-treated particles, 90 parts of spherical calcium carbonate (trade name: TP-S010, manufactured by Okutama Kogyo Co., Ltd.) having an average particle size of 10 μm was added to 99.5 parts, and a polyethylene wax emulsion (trade name: Nopcoat PEM17, A coated paper was obtained in the same manner as in Example 1 except that 10 parts (manufactured by San Nopco) was changed to 0.5 parts.

Example 10
When preparing the surface-treated particles, 90 parts of spherical calcium carbonate (trade name: TP-S010, manufactured by Okutama Kogyo Co., Ltd.) having an average particle size of 10 μm was added to 98 parts, and a polyethylene wax emulsion (trade names: Nopcoat PEM17, Sannopco) Product) Coated paper was obtained in the same manner as in Example 1 except that 10 parts were changed to 2 parts.

Example 11
When preparing the surface-treated particles, 90 parts of spherical calcium carbonate having an average particle diameter of 10 μm (trade name: TP-S010, manufactured by Okutama Kogyo Co., Ltd.) is added to 80 parts, and a polyethylene wax emulsion (trade names: Nopcoat PEM17, San Nopco) Product) Coated paper was obtained in the same manner as in Example 1 except that 10 parts were changed to 20 parts.

Comparative Example 1
Example 1 except that 3 parts of spherical calcium carbonate (trade name: TP-S010, manufactured by Okutama Kogyo Co., Ltd.) having an average particle diameter of 10 μm was used in place of 3 parts of the surface-treated particles when preparing the coating liquid. A coated paper was obtained in the same manner.

Comparative Example 2
In the preparation of the coating liquid, the coated paper was prepared in the same manner as in Example 1 except that 1 part of polyethylene wax emulsion (trade name: Nopcoat PEM17, manufactured by San Nopco) was blended instead of 3 parts of the surface-treated particles. Obtained.

Comparative Example 3
When preparing the coating liquid, instead of 3 parts of the surface-treated particles, 3 parts of spherical calcium carbonate (trade name: TP-S010, manufactured by Okutama Kogyo Co., Ltd.) having an average particle diameter of 10 μm and a polyethylene wax emulsion (trade name: Nopcoat PEM17) , Manufactured by San Nopco), coated paper was obtained in the same manner as in Example 1 except that 1 part was blended.

Evaluation method [coefficient of friction between papers]
Measurement was performed at a load of 240 g and a pulling speed of 200 mm / min by using a method according to JIS P 8147 (horizontal method) using A3 size paper in an environment of 23 ° C. and 50% RH.

[Printer runnability evaluation]
Using a color copier Imagio Neo C455 manufactured by Ricoh Co., Ltd., running performance was evaluated by performing color printing on 100 sheets of A3 size paper continuously at a printing speed of 12 sheets / minute under an environment of 23 ° C. and 50% RH.
○: No problem △: Almost no problem ×: Problem

The coated paper according to the present invention can be stably run even with high-speed copying machines and printers, and is extremely useful in practice.

Claims (8)

A coated paper comprising a paper base material and a coating layer mainly comprising a pigment and an adhesive on at least one surface thereof, the coating layer containing coarse particles, and the coarse particles A coated paper, wherein the surface-treated particles are surface-coated with a lubricant. In a coated paper comprising a paper base material and a plurality of coating layers mainly composed of a pigment and an adhesive on at least one surface thereof, the outermost surface layer of the coating layer contains coarse particles. The coated paper is characterized in that the coarse particles are surface-treated particles whose surface is coated with a lubricant. The lubricant is an aliphatic hydrocarbon lubricant, a higher aliphatic alcohol lubricant, a higher fatty acid lubricant, a higher fatty acid amide lubricant, a higher fatty acid metal salt lubricant, a higher fatty acid ester lubricant and a combination of two or more thereof. The coated paper according to claim 1 or 2, which is at least one selected from lubricants. The coated paper according to claim 1 or 2, wherein an average particle diameter of the surface-treated particles is 3.0 to 50.0 µm. The coated paper according to any one of claims 1 to 4, wherein a processing amount of the lubricant used for the surface coating is 1 to 30 parts by mass with respect to 100 parts by mass of the coarse particles. The coated paper according to any one of claims 1 to 5, wherein the coarse particles are spherical calcium carbonate. The coated paper according to claim 1 or 2, wherein the surface coating is performed using a lubricant in an emulsion state. The coated paper according to any one of claims 1 to 7, wherein the lubricant is an aliphatic hydrocarbon lubricant.