JP5113860B2 - Glossy paper for inkjet recording and method for producing the same - Google Patents

Description

  In the glossy paper for ink-jet recording produced by the cast coating method, the present invention has a high gloss feeling similar to that of a silver salt photograph while having good ink absorption and image sharpness particularly with respect to dye ink and pigment ink, Further, the present invention relates to a glossy paper for ink-jet recording and a method for producing the same, which are less susceptible to printer conveyance flaws.

  The ink jet recording system is a system in which ink droplets are ejected and deposited on recording paper to form dots and recording is performed. In recent years, recording with high print quality has become possible due to technological advances in ink jet printers, inks, and recording media. If ordinary plain paper has a certain size or more, it can be expected to have a certain level of print quality with less blur. However, when a higher print quality is required, a dedicated medium in which an ink receiving layer suitable for the ink of an ink jet printer is provided on various substrates is used. As these ink jet recording media, either a paper or film or both of them are used as a support, and a pigment coating layer mainly composed of a pigment and a binder or a resin coating layer not containing a pigment is provided on the surface. Are often used.

  Inkjet recording media are further classified into matte and glossy media from the surface state. The latter glossy medium is used when image quality closer to silver halide photography is required. As a method for producing a glossy medium, general methods include a method of forming an ink receiving layer by a cast coating method to impart gloss to the surface and a method of forming an ink receiving layer on a photographic paper substrate.

  Since the latter photographic paper base is generally formed of a polyethylene film layer on a paper base, as is called RC paper (resin coated paper), when an ink receiving layer is formed on the surface thereof, Since the film surface is smooth, the surface of the ink receiving layer is also smooth, and a glossy surface is easily formed. However, the overall cost needs to be increased in order to increase ink absorbency, and the base material itself is more expensive than paper, so it is higher than the former glossy media produced by the cast coating method. It becomes. In addition, when it is discarded, there is a problem that it cannot be recycled because it is a composite material. From the ecological point of view, the glossy media manufactured by the paper-based recyclable cast coating method has an advantage. .

  On the other hand, not only dye inks using dye colorants that have been the mainstream in the past, but also pigment inks in which colored pigments having excellent storage stability such as water resistance and light resistance are used. The average particle diameter of the color pigments used in these pigment inks is about 50 to 100 nm, which is 5 to 10 times the size of the dye colorant molecule, and therefore the absorption speed is inevitably different. Therefore, in order to make the glossy medium suitable for both inks, it is necessary to design an ink receiving layer different from the conventional recording medium dedicated to dye ink.

  Since the surface of the glossy medium requires high ink absorbency as well as high gloss, the pigment used in the glossy layer is often made of ultrafine particles having a high specific surface area of the nano order. It has become to. Examples of these ultrafine particles include gas phase method silica.

  As a proposal of glossy paper for ink jet recording having suitability for dye ink and pigment ink, for example, ink jet which adjusts glossiness at a high level by using gas phase method silica and colloidal silica having secondary particles as a pigment of a gloss developing layer Glossy paper for recording has been proposed (see, for example, Patent Document 1).

  In addition, as a proposal for glossy paper for ink-jet recording having suitability for dye ink and pigment ink, ink-jet recording cast-coated by a coagulation method in which a coagulation liquid containing a nonionic release agent, an anionic release agent and a surfactant is applied. Paper has been proposed (see, for example, Patent Document 2).

JP 2005-212327 A JP 2009-56675 A

  When vapor-phase process silica is used as a pigment for the glossy layer, there is a problem in that printer transport flaws on the glossy surface tend to be conspicuous as the coating layer strength decreases due to the weak bonding force between the particles. Further, due to the high friction property derived from the high specific surface area property, the load on the glossy surface when contacting the printer transport roller is large, which promotes the occurrence of the printer transport flaw.

  In the case of the technique described in Patent Document 1 or 2, the glossy surface is highly glossy and excellent in suitability for dye ink and pigment ink. There is a problem that occurs. As described above, the glossy paper for ink jet recording described in Patent Document 1 or 2 has a defect that the surface of the glossy layer is easily scratched (is easily noticeable) because it is excellent in glossiness.

  From the results of research on the scratch resistance on the surface of the glossy layer by the present inventors, it has been concluded that it is difficult to satisfy both the suitability of dye ink and pigment ink and the scratch resistance of the surface of the glossy layer with the above proposals. It was. In view of the current situation, glossy paper for ink-jet recording produced by the cast coating method is suitable for dye ink and pigment ink, and has an image quality exceeding that of an ink-jet recording medium produced using a photographic paper substrate or film substrate. At present, there is no ink jet recording medium having a uniform gloss feeling and a very excellent gloss developing layer surface scratch resistance.

  Accordingly, an object of the present invention is to provide glossy paper for ink-jet recording produced by a cast coating method, having a glossiness equivalent to that of a silver salt photograph while having suitability for dye inks and pigment inks, and further having a glossy layer surface. An ink jet recording medium that is extremely excellent in scratch resistance, has an image quality comparable to that of an ink jet recording medium manufactured using a photographic paper base or a film base, and has a uniform gloss, and a method for manufacturing the same. It is to be.

  The glossy paper for ink-jet recording according to the present invention is provided with at least one ink receiving layer on at least one side of a paper substrate, and contains a pigment, a binder, and a lubricant on the outermost layer of the ink receiving layer. A glossy paper for ink-jet recording in which a glossy developing layer is provided by a cast coating method, wherein the glossy developing layer contains gas phase method silica and monodispersed spherical colloidal silica as the pigment, and the lubricant And a higher fatty acid salt and a polyethylene emulsion, and the monodispersed spherical colloidal silica has an average particle size of 50 to 300 nm.

  In the glossy paper for ink-jet recording according to the present invention, the mass ratio of the monodispersed spherical colloidal silica and the vapor phase silica is preferably 20/80 to 70/30. It is possible to achieve compatibility between ink suitability (absorbency and image sharpness) of dye ink and pigment ink and gloss surface scratch resistance at a higher level.

In the glossy paper for ink-jet recording according to the present invention, the gas phase method silica preferably has a BET specific surface area of 200 to 400 m ² / g. It becomes possible to make the ink absorptivity and image sharpness of the dye and pigment ink more excellent.

  In the glossy paper for inkjet recording according to the present invention, the cast coating method for forming the glossy expression layer is a coagulation method, and the coagulation liquid contains a higher fatty acid salt and a polyethylene emulsion as the lubricant. Is preferred. It is possible to further improve the lubricity of the surface of the glossy layer and reduce printer transport flaws.

  In the glossy paper for inkjet recording according to the present invention, the glossy layer preferably contains any one or more of laurate, myristate, and oleate as the higher fatty acid salt. It is possible to further improve the lubricity of the surface of the glossy layer and reduce printer transport flaws.

  In the glossy paper for inkjet recording according to the present invention, the glossy expression layer contains silanol-modified polyvinyl alcohol as the binder, and the content of the silanol-modified polyvinyl alcohol is contained in the glossy expression layer. It is preferable that it is 1-10 mass parts with respect to 100 mass parts of said pigments. It is possible to increase the surface strength and reduce printer conveyance flaws.

  In the glossy paper for ink-jet recording according to the present invention, the coagulating liquid preferably contains either or both of sodium borate and boric acid as a coagulant. It becomes possible to make the glossiness of the surface of the glossy layer more excellent.

  In the method for producing glossy paper for ink jet recording according to the present invention, at least one ink receiving layer is provided on at least one side of a paper substrate, and a pigment, a binder, and a lubricant are provided on the outermost layer of the ink receiving layer. A glossy paper for ink-jet recording provided with a gloss-expressing layer containing a cast coating method, comprising vapor phase method silica and monodispersed spherical colloidal silica as a pigment on the outermost layer of the ink receiving layer and a binder And a step of applying a coating liquid for a glossy layer having an average particle size of the monodispersed spherical colloidal silica of 50 to 300 nm, and the obtained coating surface is in a wet state, A metal surface with a mirror-finished surface that contains a coagulant and the lubricant, and the lubricant is applied with a coagulation liquid containing a higher fatty acid salt and a polyethylene emulsion on the coated surface, solidified, and heated ( Less than , Characterized by having a step of also there.) And dried and pressed to form a glossy layer be referred to as a casting drum.

  The glossy paper for ink-jet recording of the present invention is a glossy paper for ink-jet recording produced by the cast coating method, but has a very good surface glossiness and ink suitability for dye ink and pigment ink (absorption, image sharpness). And the scratch resistance of the glossy layer surface at a high level. In addition, the method for producing glossy paper for inkjet recording of the present invention can impart scratch resistance to the glossy layer in an economically advantageous manner without increasing new steps. Furthermore, in the present invention, since the paper is used as a base material, the manufacturing cost is low compared with a photographic paper base material having a film layer, and it can be recycled when discarded, which is preferable from the viewpoint of effective use of resources. .

  Next, the present invention will be described in detail with reference to embodiments, but the present invention is not construed as being limited to these descriptions. As long as the effect of the present invention is exhibited, the embodiment may be variously modified.

  In the glossy paper for ink-jet recording according to this embodiment, at least one ink receiving layer is provided on at least one side of a paper base material, and a pigment, a binder, and a lubricant are provided on the outermost layer of the ink receiving layer. The gloss developing layer is a glossy paper for ink jet recording provided by a cast coating method, wherein the gloss developing layer contains gas phase method silica and monodispersed spherical colloidal silica as the pigment, and the lubrication A higher fatty acid salt and a polyethylene emulsion are contained as an agent, and the monodispersed spherical colloidal silica has an average particle size of 50 to 300 nm.

  Examples of pigments commonly used in the glossy layer of glossy paper for inkjet recording by the cast coating method include monodispersed spherical colloidal silica, non-spherical colloidal silica in which a plurality of spherical colloidal silicas are connected, gas phase method silica, and alumina. It is done.

  Monodispersed spherical colloidal silica has a high hardness as a material and can form a highly scratch-resistant surface. On the other hand, since the particles themselves do not have voids, the ink absorbability and the image sharpness tend to be relatively poor when a glossy expression layer is formed.

  Non-spherical colloidal silica in which a plurality of spherical colloidal silicas are connected includes non-spherical colloidal silica in which a plurality of spherical colloidal silicas are randomly connected, non-spherical colloidal silica in which a plurality of spherical colloidal silicas are connected in a pearl necklace shape, etc. Are known.

  As a result of the inventors' research on the scratch resistance of the glossy layer, non-spherical colloidal silica is easier to form voids during film formation than its monodispersed spherical colloidal silica, resulting in improved ink absorption. On the other hand, it has been found that there is an unsatisfactory point in achieving the objective of having a surface property that is very excellent in scratch resistance due to the tendency to plastic deformation and cracking due to the porosity at the time of film formation. In addition, it has been found that the fact that the coefficient of friction on the surface of the glossy layer is more likely to be higher than that of monodispersed spherical colloidal silica is a disadvantage for scratch resistance.

  Gas phase method silica is a pigment generally used in glossy paper for ink-jet recording because of its excellent ink absorption due to its extremely high specific surface area, and is particularly suitable for pigment ink. However, it is extremely difficult to provide high scratch resistance for the same reason as non-spherical colloidal silica. In addition, the fact that the coefficient of friction of the glossy layer surface tends to increase is also a disadvantage for scratch resistance. In general, compared to non-spherical colloidal silica, voids during film formation are more likely to be formed, and therefore, plastic deformation and cracking on the surface of the glossy layer are more likely to occur, and the scratch resistance tends to be inferior. Further, compared to non-spherical colloidal silica, the friction coefficient on the surface of the glossy layer is likely to be increased, and the scratch resistance tends to be inferior.

  Alumina is also a pigment that is very often used because of its excellent ink absorbability and glossiness, and particularly good pigment ink suitability. It is a result that it is extremely difficult to give. In addition, the fact that the coefficient of friction of the glossy layer surface tends to increase is also a disadvantage for scratch resistance. In general, compared to non-spherical colloidal silica, voids during film formation are more likely to be formed, and therefore, plastic deformation and cracking on the surface of the glossy layer are more likely to occur, and the scratch resistance tends to be inferior. Further, compared to non-spherical colloidal silica, the friction coefficient on the surface of the glossy layer is more likely to be increased, so that the scratch resistance tends to be inferior. Moreover, it can be said that it is expensive compared with a silica pigment.

  Based on the above research results, in view of the properties of the pigment, when trying to obtain a glossy paper for ink-jet recording that is truly excellent in scratch resistance, it is limited to spherical colloidal silica that can be used as the pigment of the glossy layer. However, as described above, there are difficulties in ink absorption and image sharpness, and in particular, there is no suitability for pigment ink, so that it is necessary to balance dye ink and pigment ink suitability and surface scratch resistance at a high level. Many technical issues remained.

  As described above, in order to improve the ink absorbability and image sharpness of the dye ink and the pigment ink, it is necessary to use pigments with relatively low scratch resistance, and those pigments were used. In some cases, there is a phenomenon that the frictional resistance becomes relatively large, and it remains a technical problem to reduce the frictional resistance while maintaining a state in which the destruction of the glossy layer is hardly generated.

  In addition, compared with a so-called matte inkjet recording medium, the friction resistance of the glossy paper for inkjet recording having a glossy expression layer aimed at replacing silver salt photography is significantly worse. The reason is presumed as follows. That is, since the pigment used in the glossy expression layer often has a smaller particle diameter than the pigment used in so-called matte inkjet recording paper, the surface is inevitably highly smooth and highly glossy, Increases true contact area. As a result, the frictional resistance is increased. Therefore, it can be said that the ink jet recording paper having the glossy expression layer is more serious than the other ink jet recording paper with respect to the surface scratch resistance problem.

  In the glossy paper for ink-jet recording according to the present embodiment, in order to achieve the above object, the gloss developing layer contains gas phase method silica and monodispersed spherical colloidal silica as pigments, and higher fatty acid as the lubricant. It is necessary to contain a salt and a polyethylene emulsion, and the monodispersed spherical colloidal silica has an average particle size of 50 to 300 nm.

  Vapor phase method silica is also called dry method silica or fumed silica, and is generally produced by flame hydrolysis. Specifically, it is manufactured by gas-phase hydrolysis of volatile silane compounds such as silicon tetrachloride in an oxyhydrogen flame, and changes the conditions such as the flame temperature, the supply ratio of oxygen and hydrogen, and the supply of raw material silicon tetrachloride. It is obtained by doing. In this embodiment, the average primary particle diameter of the vapor phase method silica is preferably 5 to 30 nm. More preferably, it is 6-25 nm, Most preferably, it is 7-20 nm. If the thickness is less than 5 nm, the ink absorbability may be inferior, and if it exceeds 30 nm, the smoothness is inferior and the frictional resistance increases, so that the scratch resistance may be inferior.

In the glossy paper for ink jet recording according to the present embodiment, the BET specific surface area of the vapor phase method silica is preferably 200 to 400 m ² / g. More preferably, it is 220-380 m < ² > / g, Most preferably, it is 250-350 m < ² > / g. If the specific surface area is less than 200 m ² / g, the image clarity of the pigment ink may be inferior. When the specific surface area exceeds 400 m ² / g, the stability of the coating solution tends to be inferior, and a problem may occur in the coating property. Here, the BET specific surface area is a surface area determined by the BET method. The BET method is one method for measuring the surface area of a powder by a gas phase adsorption method, and is a method for obtaining the total surface area, that is, the specific surface area of a 1 g sample from a temperature line such as adsorption. Usually, nitrogen gas is often used as the adsorbed gas, and the most frequently used method is to measure the amount of adsorption from the change in pressure or volume of the gas to be adsorbed. The most prominent expression for representing a temperature line such as multimolecular adsorption is the Brunauer, Emmett, and Teller equation, called the BET equation, which is widely used for determining the surface area. The adsorption amount is obtained based on the BET equation, and the surface area is obtained by multiplying the area occupied by one adsorbed molecule on the surface.

  The monodispersed spherical colloidal silica used in the present embodiment is monodispersed fine particles, the particle diameter is substantially uniform, and is not aggregated. Here, monodispersed means a state in which the particle size distribution is sharp and the particles are present as primary particles dispersed individually without agglomeration. The spherical shape includes a shape close to a spherical shape, and preferably means a true sphere. The average particle diameter of the monodispersed spherical colloidal silica is 50 to 300 nm. Preferably, it is 60-200 nm, Most preferably, it is 70-180 nm. When the particle size of the monodispersed spherical colloidal silica is less than 50 nm, the surface of the coating film becomes brittle and the coefficient of friction increases, resulting in poor scratch resistance. On the other hand, when the particle diameter exceeds 300 nm, the film formability of the coating film is too good and the ink absorbability of the pigment ink is poor. In the present embodiment, monodispersed spherical colloidal silica can be used by blending a plurality of types having different particle diameters within the range of the particle diameters. In addition, the monodispersed spherical colloidal silica used in the present embodiment may be used in any manufacturing method as long as it is within the particle diameter range. The particle diameter of monodispersed spherical colloidal silica can be determined mainly by a dynamic light scattering method (for example, DLS-6500, manufactured by Otsuka Electronics Co., Ltd.), or a field emission type electron microscope capable of high-magnification observation. It can also be obtained by direct observation.

  In the glossy paper for ink-jet recording according to the present embodiment, the mass ratio of monodispersed spherical colloidal silica and gas phase method silica is preferably 20/80 to 70/30. More preferably, it is 30/70 to 60/40, and particularly preferably 35/65 to 55/45. When the mass ratio of the monodispersed spherical colloidal silica and the vapor phase method silica exceeds 70/30, the image clarity of the pigment ink may be inferior, and when it is less than 20/80, the strength of the gloss developing layer decreases, and In some cases, since the coefficient of friction is high, the surface of the glossy layer is inferior in scratch resistance.

  In addition to the pigment, other pigments can be used in combination as long as the effects of the present invention are not impaired. Examples of other pigments include colloidal silica (including non-spherical colloidal silica), synthetic amorphous silica, alumina-modified silica, γ-alumina, θ-alumina, σ-alumina, and pseudoboehmite. However, from the viewpoint of satisfying all of the absorptivity, image sharpness and scratch resistance of the dye ink / pigment ink, the monodispersed spherical colloidal silica having an average particle diameter of 50 to 300 nm and the vapor phase method silica are used. It is necessary to use the main pigment. Therefore, it is preferable that the total content of monodispersed spherical colloidal silica and gas phase method silica is 70% by mass or more in terms of dry mass among all the pigments in the glossy layer. More preferably, it is 80 mass% or more, Most preferably, it is 100 mass%.

  Further, in the present embodiment, it is necessary to contain a lubricant in the glossy layer in order to achieve the above object. Here, the term “lubricant” refers to a substance that provides an antifriction action for the contact portion. Examples of the lubricant include a liquid lubricant, a solidified liquid lubricant, and a solid lubricant. As a method for incorporating a lubricant into the glossy layer, (1) a method of coating the glossy layer in the coating solution, and (2) a treatment solution containing the lubricant after the glossy layer is applied. There is a method of coating. In the present embodiment, the timing and method of adding the lubricant to the glossy layer are not limited, and the method (1), the method (2), or both methods may be used. However, the method (2) is more preferable because the surface of the glossy layer is further subjected to anti-friction. In the present embodiment, the glossy layer needs to contain a higher fatty acid salt and a polyethylene emulsion as a lubricant. By using a higher fatty acid salt and a polyethylene emulsion in combination, a further anti-friction effect can be obtained and scratch resistance can be increased.

  Examples of the higher fatty acid salt include laurate, oleate, palmitate, stearate, and myristate. Further, these sodium salts and potassium salts, so-called soaps are included. Further, ammonium laurate, ammonium oleate, ammonium palmitate, ammonium stearate, and ammonium myristate. Among these, in this embodiment, it is preferable that the glossy layer contains at least one of laurate, myristate, and oleate as a higher fatty acid salt. By including the higher fatty acid salt, it is possible to further improve the lubricity of the glossy layer surface, reduce the friction coefficient, and reduce printer conveyance scratches.

  The polyethylene emulsion is, for example, a high-density polyethylene emulsion or a low-density polyethylene emulsion. In this embodiment, although it is not limited to the kind and manufacturing method of polyethylene emulsion, it is preferable that melting | fusing point is 70-120 degreeC, More preferably, it is 80-110 degreeC. If it is less than 70 ° C., the scratch resistance may be inferior, and if it exceeds 120 ° C., the image clarity of the pigment ink may be inferior. The average primary particle size of the polyethylene emulsion is preferably 10 to 500 nm. More preferably, it is 20-300 nm.

  The higher fatty acid salt is preferably added in an amount of 0.005 to 20.000% by mass with respect to the total pigment in the glossy layer. More preferably, it is 0.010 to 10.000 mass%. If it is less than 0.005% by mass, the anti-friction effect may be small, and if it exceeds 20.000% by mass, the image clarity may be inferior. The polyethylene emulsion is preferably added in an amount of 0.005 to 20.000% by mass with respect to all the pigments of the glossy layer. More preferably, it is 0.010 to 10.000 mass%. If it is less than 0.005% by mass, the anti-friction effect may be small, and if it exceeds 20.000% by mass, the ink absorbency may be inferior. Moreover, it is inferior in air permeability, and may not be suitable for a cast coat process. The mass ratio between the higher fatty acid salt and the polyethylene emulsion is preferably 99/1 to 1/99. More preferably, it is 95/5 to 5/95. About a higher fatty acid salt and a polyethylene emulsion, you may use multiple types, respectively.

  Furthermore, the lubricants listed below may be used in combination as long as the effects of the present invention are not impaired. Examples of the lubricant include surfactants, waxes, and organosilicon compounds. Next, each lubricant will be described in detail.

  As the surfactant, any of ionicity of the hydrophilic portion among cationic, anionic, amphoteric and nonionic can be used. Moreover, although it illustrates next, respectively, if it is a range which does not impair the effect of this invention, it will not be limited to the surfactant specifically illustrated. Examples of cationic compounds include quaternary ammonium salt systems such as alkylbenzyldimethylammonium salts, dialkyltrimethylammonium salts, and alkyltrimethylammonium salts. Examples of anionic compounds include higher fatty acids such as lauric acid, oleic acid, palmitic acid, stearic acid, myristic acid, monoalkyl sulfates, alkyl polyoxyethylene sulfates, alkylbenzene sulfonates, and monoalkyl phosphates. can do. In the present embodiment, the higher fatty acid salt, which is an essential drug, is also anionic. As for amphoteric ones, alkyldimethylamine oxide and alkylcarboxybetaine can be exemplified. Nonionic compounds include polyoxyethylene alkyl ethers, fatty acid sorbitan esters, alkyl polyglucosides, fatty acid diethanolamides, and alkyl monoglyceryl ethers. Moreover, it is also possible to use a fluorine-type surfactant and a silicone-type surfactant suitably. In addition, the surface tension varies depending on the various surfactants, but since the correlation between the surface tension and the anti-friction effect is not always recognized, it is possible to appropriately select the surfactant and its combination ratio according to the desired anti-friction effect. preferable.

  As waxes, vegetable waxes, animal waxes, montan waxes, paraffin waxes, hydrocarbon synthetic waxes, higher fatty acid esters, fatty acid amides, ketones / amines, hydrogenated oils and other synthetic waxes, polypropylene, polytetrafluoroethylene Although it can select suitably from aliphatic hydrocarbons, such as a polymer, or its derivative (s), if it is a range which does not impair the effect of this invention, it will not specifically limit.

  Examples of organosilicon compounds include polyalkylsiloxanes or derivatives thereof, dimethyl silicone, methylphenyl silicone oil, alkyl modified silicone oil, alkyl / aralkyl modified silicone oil, amino modified silicone oil, polyether modified silicone oil, higher fatty acid modified silicone oil, A low-molecular or high-molecular silicone oil such as a carboalkyl-modified silicone oil, a fluorine-modified silicone oil, and an epoxy-modified silicone oil, silicone rubber, and the like can be selected as appropriate, provided that the effects of the present invention are not impaired. There is no particular limitation.

  In the present embodiment, it is preferable that the glossy layer contains silanol-modified polyvinyl alcohol as a binder. In order to suppress the plastic deformation degree of the gloss developing layer to a minimum, it is necessary to increase the binder component in the gloss developing layer, that is, the resin component as much as possible. As a result of intensive studies by the present inventors, it has been found that polyvinyl alcohol is the most effective resin for minimizing plastic deformation of the coating layer. However, film formation is not possible with ordinary unmodified polyvinyl alcohol alone. In some cases, the ink absorptivity may be lowered due to being too strong. Since the silanol-modified polyvinyl alcohol has a silanol group, it has extremely high adhesion to inorganic substances. Therefore, the coagulation force is strong, and even if the addition amount is relatively small, the coating film tends to be strong and the ink absorbability tends to be excellent. Therefore, even when the above-described pigment having low scratch resistance is used for the glossy layer, it is possible to achieve both scratch resistance and ink absorbability at a high level. The degree of modification and the degree of polymerization of the silanol-modified polyvinyl alcohol used in the present embodiment can be appropriately selected. In this embodiment, it is preferable that the addition amount of silanol modified polyvinyl alcohol is 1-10 mass parts with respect to 100 mass parts of pigments. Considering the balance between the ink absorbability and the scratch resistance of the glossy layer surface, the amount is more preferably 2 to 8 parts by mass, and particularly preferably 3 to 7 parts by mass. When the amount is less than 1 part by mass, the scratch resistance of the glossy layer may be inferior, and when the amount added exceeds 10 parts by mass, the ink absorbency may be inferior. In addition, the stability of the coating liquid tends to be inferior, and there may be a problem in coating properties. In addition, a known binder other than silanol-modified polyvinyl alcohol can be used in combination with the glossy layer as a binder.

  Known binders that can be used in combination are polyvinyl alcohol, modified polyvinyl alcohol such as carboxyl-modified polyvinyl alcohol, polyvinyl acetal, oxidized starch, etherified starch, carboxymethylcellulose, hydroxyethylcellulose, casein, gelatin, soy protein, polyethyleneimide Resin, polyvinylpyrrolidone resin, polyacrylic acid or copolymer thereof, maleic anhydride copolymer, acrylamide resin, acrylate ester resin, polyamide resin, acrylic resin, styrene-acrylic resin, polyurethane Resin, polyester resin, polyvinyl butyral resin, alkyd resin, epoxy resin, epichlorohydrin resin, urea resin, melamine resin, styrene-butadiene copolymer, methyl Acrylate polymer latexes such as methacrylate-butadiene copolymer, acrylic acid ester, methacrylic acid ester polymer or copolymer, vinyl polymer latexes such as ethylene-vinyl acetate copolymer, colloidal silica and the like Examples include a composite resin of acrylic resin and a composite resin of colloidal silica and styrene-acrylic resin. These can be used alone or in combination. Although it is preferable to contain polyvinyl alcohol from the viewpoint of achieving both ink absorbability and excellent glossiness, as described above, the addition amount of unmodified polyvinyl alcohol is the amount of the gloss-expressing layer due to the strong film-forming property. Of all the binders, the dry mass is preferably 80% by mass or less. The amount of all binders used in the glossy layer is determined in consideration of the printability of the inkjet recording medium, the strength of the glossy layer, the surface glossiness, the liquidity of the coating liquid, and the like. Usually, it is added in the range of 1 to 100 parts by mass with respect to 100 parts by mass of the pigment. Preferably, it is added in the range of about 5 to 60 parts by mass, more preferably 10 to 50 parts by mass. If the amount is less than 1 part by mass, the coating layer strength may decrease. If it exceeds 100 parts by mass, the ink absorbability may decrease.

  Furthermore, it is preferable to add a cationic polymer to the glossy layer as an ink fixing agent for fixing the ink for ink jet recording. Various auxiliary agents such as dispersants, thickeners, preservatives, antifoaming agents, colored dyes, coloring pigments, fluorescent brighteners, water resistance agents, antioxidants, UV absorbers, etc. may be appropriately selected and added. it can.

The gloss developing layer contains a pigment containing a vapor phase method silica and monodispersed spherical colloidal silica and a binder, and the average particle size of the monodispersed spherical colloidal silica is 50 to 300 nm. After the coating liquid is applied, it is provided by a cast coating method. Examples of the coating method for the glossy layer coating liquid include known coating machines such as an air knife coater, roll coater, reverse roll coater, bar coater, comma coater, blade coater, and simultaneous multilayer coater. May be used. Amount of coating is, 3 to 20 g / ^{m 2} in terms of solid content, preferably in the range of 5 to 15 g / ^{m 2.} When the coating amount exceeds 20 g / m ² , productivity may be inferior, and when the coating amount is less than 3 g / m ² , a sufficient glossy surface may not be obtained.

  The gloss developing layer is formed by a known cast coating method. As the cast coating method, a wet method, a coagulation method, and a rewet method are known, and in this embodiment, the coagulation method is preferable. In the solidification method, a gloss-expressing layer is applied, and the resulting coated surface is wetted and solidified by applying a solidifying solution, and then pressed and dried on a heated mirror-finished metal surface. Is the method. Here, the coagulation liquid refers to an aqueous solution of a coagulant. It is important to select a coagulant that effectively coagulates with the binder component of the coating layer. In this embodiment, a boron compound is preferable. More preferably, either or both of sodium borate and boric acid are used. A more uniform glossy surface can be obtained. The concentration of the coagulation liquid is preferably 0.1% by mass or more. If it is less than 0.1% by mass, the coagulation force may be insufficient. More preferably, it is 0.5 mass% or more. The content of 1.0% by mass or more is particularly preferable because the coagulation force becomes stronger and the scratch resistance can be improved. The upper limit value of the concentration of the coagulating liquid is preferably 10% by mass from the viewpoint of workability and cost. The content of the coagulant is preferably 5% by mass or more based on the binder that can coagulate. More preferably, it is 10 mass% or more, and particularly preferably 20 mass%. If it is less than 5% by mass, the surface strength may be lowered.

  In the glossy paper for ink jet recording according to the present embodiment, the cast coating method for forming the glossy expression layer is a coagulation method, the coagulation liquid contains the coagulant, and a higher fatty acid salt as the lubricant And a polyethylene emulsion. It is more excellent in the lubricity of the glossy layer surface, and it is possible to reduce printer transport flaws. As described above, the coagulation method can further improve the scratch resistance, and by adding a lubricant to the coagulation liquid, it can be economically advantageous to contain the lubricant in the glossy layer without increasing new processes. Can be made. Further, it is possible to add a cationic polymer for fixing the ink to the coagulation liquid. By adjusting the time from application of the glossy layer to application of the coagulation liquid, the time from application of the coagulation liquid to the arrival of the cast drum, the temperature of the cast drum, the pressure at the time of pressure bonding, or the line speed Further, the glossiness of the gloss developing layer can be further increased. About these various conditions, it is necessary to make it suitable by calculating | requiring optimal conditions according to the installation to be used and a coating liquid.

  In addition, calendar processing such as machine calendar, soft calendar, super calendar, etc. may be performed after cast processing, and for curl adjustment, water, curling agent etc. are coated on the back side or humidified to adjust curl. Can also be done.

  Further, the image clarity of the gloss-developing layer under the condition of an optical comb width of 2 mm and an incident reflection angle of 60 ° according to JIS H 8686-2: 1999 “Image clarity test method of anodized film of aluminum and aluminum alloy” should be 50% or more. Is preferable from the viewpoint of glossiness. More preferably, the image clarity is 55% or more. If the image clarity is 60% or more, it can be said that the glossiness is further improved. Here, the reason for changing the incident / reflective angle from 45 ° described in JIS to 60 ° is to facilitate evaluation of the difference in glossiness.

  In the glossy paper for ink-jet recording of this embodiment, it is necessary from the viewpoint of economy and ink absorbency to provide one or more ink receiving layers under the glossy expression layer. The ink receiving layer contains a white pigment and a binder component as main components.

  The pigment used in the ink receiving layer is not particularly limited in the present embodiment, and includes one or more known white pigments. Examples include kaolin, talc, calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, and carbon dioxide. White inorganic pigments such as titanium, zinc oxide, zinc sulfate, zinc carbonate, calcium silicate, aluminum silicate, magnesium silicate, diatomaceous earth, aluminum hydroxide, magnesium hydroxide, satin white, synthetic silica, colloidal silica, alumina, acrylic, styrene, Examples include organic pigments such as ethylene, vinyl chloride, and nylon. Among these, it is particularly preferable to use synthetic silica from the viewpoint of ink absorbability. These pigments can be used alone or in appropriate combination of two or more.

  The binder contained in the ink receiving layer is polyvinyl alcohol, silanol-modified polyvinyl alcohol, modified polyvinyl alcohol such as carboxyl-modified polyvinyl alcohol, polyvinyl acetal, oxidized starch, etherified starch, carboxymethylcellulose, hydroxyethylcellulose, casein, gelatin, soybean Protein, polyethyleneimide resin, polyvinylpyrrolidone resin, polyacrylic acid or copolymer thereof, maleic anhydride copolymer, acrylamide resin, acrylate resin, polyamide resin, polyurethane resin, polyester resin, Polyvinyl butyral resin, alkyd resin, epoxy resin, epichlorohydrin resin, urea resin, melamine resin, styrene-butadiene copolymer, methyl methacrylate Examples include acrylic polymer latexes such as rate-butadiene copolymer, acrylic acid ester, methacrylic acid ester polymer or copolymer, and vinyl polymer latexes such as ethylene-vinyl acetate copolymer, Used alone or in combination. In particular, it is preferable to use polyvinyl alcohol and an ethylene-vinyl acetate copolymer in combination. The amount of the binder used is determined in consideration of the printability of the ink jet recording medium, the strength of the ink receiving layer, and the characteristics of the coating liquid. Usually, it is added in the range of 1 to 200 parts by mass with respect to 100 parts by mass of the pigment. Preferably, it is added in the range of about 5 to 100 parts by mass. If the amount is less than 1 part by mass, the coating layer strength may decrease. If it exceeds 200 parts by mass, the ink absorbability may decrease.

  It is preferable to add a cationic polymer to the ink receiving layer in addition to the pigment and the binder. The cationic polymer acts as an insoluble salt in the water by reacting with anionic components in the dye used in the ink, so the dye ink is more firmly fixed on the ink receiving layer. Water resistance is improved. Such cationic polymers include polyethyleneimine, epichlorohydrin-modified polyalkylamine, polyamine, polyamine polyamide epichlorohydrin, dimethylamine ammonia epichlorohydrin, polyvinylbenzyltrimethylammonium halide, polydiacryldimethylammonium halide, polydimethylaminoethyl methacrylate hydrochloride, polyvinyl Pyridium halide, cationic polyacrylamide, cationic polystyrene copolymer, diallyldimethylammonium chloride polymer, diallyldimethylammonium chloride sulfur dioxide copolymer, diallyldimethylammonium chloride amide copolymer, dicyandiamide formalin polycondensate, dicyandiamide diethylenetriamine Polycondensate Polyallylamine, polyallylamine hydrochloride, polyacrylamide resin, polyamide epoxy resin, melamine resin acid colloid, urea resin, cation-modified polyvinyl alcohol, amino acid type amphoteric surfactant, betaine type compound, and other quaternary ammonium salts Used. Although the addition amount is not particularly limited, it is used in the range of 1 to 50 parts by mass with respect to 100 parts by mass of the pigment. Preferably, it is added in the range of about 5 to 40 parts by mass. If it is less than 1 part by mass, the water resistance of the printed part may be lowered. If it exceeds 50 parts by mass, the ink absorbability may be inferior.

  Other auxiliary agents include antifoaming agents, dispersants, wetting agents, fluorescent brighteners, colored dyes, coloring pigments, thickeners, preservatives, water-resistant agents, UV absorbers and antioxidants as necessary. Etc. can be added and used.

The ink receiving layer is prepared by blending various components contained in the ink receiving layer such as the above-mentioned pigments and binders, applying an ink receiving layer coating liquid adjusted to an appropriate solid content concentration, and drying the coating. be able to. There are known coating machines such as an air knife coater, roll coater, bar coater, comma coater, blade coater, and simultaneous multilayer coater as the coating method of the coating liquid for forming the ink receiving layer. May be used. The coating amount is not particularly limited, but is preferably 5 to ²⁰ g / m ² . More preferably 6 to 15 g / ^{m 2.} If it is less than 5 g / m ² , the ink absorptivity may be inferior, and if it exceeds 20 g / m ² , binder migration may occur during coating of the glossy layer and the scratch resistance on the surface of the glossy layer may be reduced. Alternatively, the ink receiving layer may be composed of two or more layers by coating the coating liquid for forming the ink receiving layer twice or more.

  Examples of the drying method after coating include hot air drying, infrared drying, and drum drying, but are not particularly limited in the present embodiment.

  If necessary, in order to obtain a certain smoothness after the ink receiving layer is dried, it can be processed by a known calendar device such as a super calendar, a machine calendar, or a soft calendar.

  The ink receiving layer and the gloss developing layer may be provided not only on one side of the paper substrate but also on both sides. It can be set as the glossy paper for inkjet recording for double-sided printing.

  As the paper substrate having air permeability used in the present embodiment, high quality paper, medium quality paper, white paperboard and the like can be used. Further, acid paper or neutral paper may be used. However, it is more preferable to use acidic paper because it tends to have excellent resistance to discoloration during storage. Here, the acidic paper refers to paper made by adding a filler such as talc or kaolin clay and an acidic chemical such as a sulfuric acid band. Taking the sulfuric acid band as an example, it reacts with moisture in the paper to produce sulfuric acid, making the paper acidic.

  Pulp used for the paper base material is hardwood bleached sulfite pulp (LBSP), hardwood bleached kraft pulp (LBKP), softwood bleached sulfite pulp (NBSP), softwood bleached kraft pulp (NBKP), deinked pulp Wood pulp such as (DIP) is advantageously used. In addition to wood pulp, non-wood pulp, synthetic pulp, synthetic fiber, or the like may be used as necessary. In consideration of the case where it is recycled as fuel, it is desirable to use ECF (Elemental Chlorine Free) pulp or TCF (Totally Chlorine Free) pulp having a low chlorine content.

  The pulp is a paper stock having an appropriate beating degree. The pulp beating degree of each layer is not limited in this embodiment, but is 350 to 600 ml CSF at Canadian standard freeness (freeness) (JIS P 8121: 1995 “Pulp Freeness Test Method”). It is preferable that More preferably, it is 400 to 580 ml CSF. If it is less than 350 ml CSF, since the fiber-to-fiber bond of the pulp becomes strong, the porosity decreases, and there is a tendency that the air resistance increases and the ink absorbability decreases. If it exceeds 600 ml CSF, the strength of the paper substrate will be reduced, and paper dust will be easily generated during guillotine cutting.

  The paper material preferably contains a filler. Known fillers such as heavy calcium carbonate, light calcium carbonate, magnesium carbonate, titanium oxide, synthetic silica, alumina, talc, calcined kaolin clay, kaolin clay, bentonite, zeolite, aluminum hydroxide, zinc oxide, etc. Can be used.

  In addition to the pulp and filler, various papermaking chemicals such as known paper strength agents, sulfuric acid bands, yield improvers, sizing agents, dyes, and fluorescent dyes can be appropriately used in the paper stock. There is no particular limitation on the preparation method, blending, and addition method of each papermaking chemical for each paper, as long as the effects of this embodiment are not impaired. In addition, it is possible to make a single layer or multiple layers by using a known paper machine such as a circular net paper machine, a long net paper machine, or a twin wire paper machine using the above-mentioned stock.

  In order to suppress excessive penetration of the coating liquid for the glossy layer, it is preferable to apply a known water-soluble polymer such as starch, polyvinyl alcohol, or polyacrylamide to the paper substrate with a size press or the like.

Although the thickness of a paper base material is not specifically limited in this embodiment, It is preferable that it is 100-360 micrometers. More preferably, it is 120-340 micrometers. Moreover, it is preferable that a basic weight is 100-300 g / m < ² >, More preferably, it is 120-280 g / m < ² >.

  Although the ink receiving layer may be directly provided on the paper base material thus manufactured, in this embodiment, for the purpose of smoothing the surface of the paper base material, a process such as a machine calendar, a soft calendar, or a raster is performed in advance. It is preferable to apply.

  Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. Further, “parts” and “%” in the examples represent “parts by mass” and “% by mass”, respectively, unless otherwise specified.

Example 1
(Formation of paper substrate)
100 parts of hardwood bleached kraft pulp (Canadian standard freeness 520 ml CSF) is graft-polymerized 1: 1 by dry mass with grafted starch (DG4204, self-modified tapioca starch of graft component and anion-crosslinked polyamide of trunk component) 1.0 parts of grafted starch copolymer having a molecular weight of 2 million (manufactured by Seiko PMC Co., Ltd.), 0.2 parts of acidic rosin sizing agent, 1.0 part of liquid sulfuric acid band and added so as to have an ash content of 5% An amount of talc (talc NTL: manufactured by Nippon Talc Co., Ltd.) was adjusted to obtain a paper stock. This stock was made using a long paper machine to obtain a paper web. Thereafter, polyacrylamide (ST5000: manufactured by Seiko PMC Co., Ltd.) was applied as a sizing solution to the both sides of the paper base with a size press so that the dry coating amount was 1.5 g / m ² per side, and dried with a cylinder dryer. Thereafter, surface treatment was performed using a steel calender under the conditions of a linear pressure of 40 kg / cm, 25 ° C., and 2 nips and 1 pass to produce an inkjet paper base material having a basis weight of 180 g / m ² .

(Formation of ink receiving layer)
On one side of this paper substrate, 100 parts of synthetic silica (Mizukasil P-78A: manufactured by Mizusawa Chemical Co., Ltd.) as a pigment, 10.0 parts of polyvinyl alcohol (PVA117: manufactured by Kuraray Co., Ltd.) as a binder, and ethylene-acetic acid 45.0 parts of vinyl (Polysol EVA AD-10: manufactured by Showa Polymer Co., Ltd.) and 30.0 parts of cationic polymer (Papiogen P-105: manufactured by Senka Co., Ltd.) were blended, and the solid content concentration was 22 with industrial water. The ink receiving layer coating solution was obtained by adjusting the content to 1%. This ink receiving layer coating solution was coated and dried with an air knife coater so that the dry coating amount was 10 g / m ² to form an ink receiving layer.

(Formation of glossy layer)
Subsequently, 30.0 parts of monodispersed spherical colloidal silica (Snowtex AK-YL, average particle size 120 nm: manufactured by Nissan Chemical Industries, Ltd.) as a pigment, and gas phase method silica (Leosil QS-30, BET specific surface area of 300 m ² / g) 70.0 parts manufactured by Tokuyama), 5.0 parts silanol-modified polyvinyl alcohol (PVA-R2105: manufactured by Kuraray Co., Ltd.) and 5.0 parts polyvinyl alcohol (PVA-235: manufactured by Kuraray Co., Ltd.) as a binder. , 15.0 parts of an acrylic resin (Vinyl Blanc 2580: manufactured by Nissin Chemical Industry Co., Ltd.) and 10.0 parts of a cationic polymer (Smileys resin 1001: manufactured by Sumitomo Chemical Co., Ltd.) as an ink fixing agent A gloss concentration layer coating solution was obtained by adjusting the solid content concentration to 20% with water. This glossy layer coating solution is applied to the surface of the base paper where the ink receiving layer is formed with an air knife coater so that the dry coating amount is 10 g / m ^2, and then 1% boron and boric acid are used as coagulants. An aqueous solution containing 1% sodium, 0.1% potassium oleate, which is a higher fatty acid as a lubricant, and 0.1% polyethylene emulsion (Mecatex HP-70, melting point 110 ° C .: manufactured by Meisei Chemical Co., Ltd.) The coagulation liquid (concentration of the coagulation liquid is 2.2%) is applied with a dip coater so that the coating amount is 1.0 g / m ^2, and the surface of the obtained coating layer is wet. While being in the state, it was pressure-bonded to a cast drum having a surface temperature of 105 ° C. to produce a glossy paper for inkjet recording of Example 1. The amount of the higher fatty acid or polyethylene emulsion added was 1.2% in terms of dry mass with respect to all the pigments in the glossy layer.

(Example 2)

  In Example 1, glossy paper for ink-jet recording was produced under the same conditions as described in Example 1 except that the higher fatty acid blended in the coagulation liquid was changed to sodium laurate.

(Example 3)
In Example 1, glossy paper for ink-jet recording was produced under the same conditions as described in Example 1 except that the higher fatty acid blended in the coagulation liquid was changed to potassium palmitate.

Example 4
In Example 1, the coagulating liquid was prepared by using 1.0% boric acid and 1.0% sodium borate as coagulants, 1.0% potassium oleate as a higher fatty acid as a lubricant, and a polyethylene emulsion (Maycatex HP- 70, melting point 110 ° C .: manufactured by Meisei Chemical Co., Ltd.) and an aqueous solution containing a solid solution (concentration of the coagulating liquid is 4.0%), and for ink jet recording under the same conditions as described in Example 1. Glossy paper was prepared. The amount of the higher fatty acid or polyethylene emulsion added was 6.8% in terms of dry mass with respect to all the pigments in the glossy layer.

(Example 5)
In Example 1, the coagulation liquid was prepared by using 1.0% boric acid and 1.0% sodium borate as coagulants, 0.01% potassium oleate, which is a higher fatty acid as a lubricant, and a polyethylene emulsion (Maycatex HP- 70, melting point 110 ° C .: manufactured by Meisei Chemical Co., Ltd.) 0.01%, and for ink jet recording under the same conditions as described in Example 1 except that the concentration of the coagulation liquid is 2.02%. Glossy paper was prepared. The amount of the higher fatty acid or polyethylene emulsion added was 0.13% by dry mass with respect to all the pigments in the glossy layer.

(Example 6)
In Example 1, glossy paper for ink-jet recording was produced under the same conditions as described in Example 1 except that the higher fatty acid blended in the coagulation liquid was changed to ammonium oleate.

(Example 7)
In Example 1, except that the polyethylene emulsion blended in the coagulation liquid was changed to a polyethylene emulsion (polylene N-20, melting point 105 ° C .: manufactured by Daikyo Chemical Co., Ltd.), the ink jet recording was performed under the same conditions as described in Example 1. Glossy paper was prepared.

(Example 8)
In Example 1, 30.0 parts of monodispersed spherical colloidal silica (MP-2040, average particle size 200 nm: manufactured by Nissan Chemical Industries, Ltd.) and gas phase method silica (Leolosil QS-) Glossy paper for ink-jet recording was prepared under the same conditions as described in Example 1 except that the content was 70.0 parts (30, BET specific surface area 300 m ² / g: manufactured by Tokuyama Corporation).

Example 9
In Example 1, 30.0 parts of monodispersed spherical colloidal silica (MP-3040, average particle size 300 nm: manufactured by Nissan Chemical Industries, Ltd.) and gas phase method silica (Leosil QS-) Glossy paper for ink-jet recording was prepared under the same conditions as described in Example 1 except that the content was 70.0 parts (30, BET specific surface area 300 m ² / g: manufactured by Tokuyama Corporation).

(Example 10)
In Example 1, 30.0 parts of monodispersed spherical colloidal silica (Snowtex OL, average particle size: 50 nm, manufactured by Nissan Chemical Industries, Ltd.) and gas phase method silica (Leolosil QS-) Glossy paper for ink-jet recording was prepared under the same conditions as described in Example 1 except that the content was 70.0 parts (30, BET specific surface area 300 m ² / g: manufactured by Tokuyama Corporation).

(Example 11)
In Example 1, 30.0 parts of monodispersed spherical colloidal silica (Snowtex AK-YL, average particle size 120 nm: manufactured by Nissan Chemical Industries, Ltd.) and gas phase method silica (Leosil) Glossy paper for inkjet recording was prepared under the same conditions as described in Example 1 except that 70.0 parts (QS-40, BET specific surface area 380 m ² / g: manufactured by Tokuyama Corporation).

(Example 12)
In Example 1, 30.0 parts of monodispersed spherical colloidal silica (Snowtex AK-YL, average particle size 120 nm: manufactured by Nissan Chemical Industries, Ltd.) and gas phase method silica (Leosil) Glossy paper for ink-jet recording was prepared under the same conditions as described in Example 1 except that 70.0 parts (QS-102, BET specific surface area 200 m ² / g: manufactured by Tokuyama Corporation).

(Example 13)
In Example 1, 1.0 part of silanol-modified polyvinyl alcohol (PVA-R2105: manufactured by Kuraray Co., Ltd.) and 5.0 parts of polyvinyl alcohol (PVA-235: manufactured by Kuraray Co., Ltd.) are used as the binder of the coating liquid for the glossy layer. A glossy paper for ink-jet recording was prepared under the same conditions as described in Example 1, except that the amount was 15.0 parts and an acrylic resin (Vinyl Blanc 2580: manufactured by Nissin Chemical Industry Co., Ltd.).

(Example 14)
In Example 1, 10.0 parts of silanol-modified polyvinyl alcohol (PVA-R2105: manufactured by Kuraray Co., Ltd.) and 5.0 parts of polyvinyl alcohol (PVA-235: manufactured by Kuraray Co., Ltd.) are used as the binder of the coating liquid for the glossy layer. A glossy paper for ink-jet recording was prepared under the same conditions as described in Example 1, except that the amount was 15.0 parts and an acrylic resin (Vinyl Blanc 2580: manufactured by Nissin Chemical Industry Co., Ltd.).

(Example 15)
In Example 1, 20.0 parts of monodispersed spherical colloidal silica (Snowtex AK-YL, average particle size 120 nm: manufactured by Nissan Chemical Industries, Ltd.) and gas phase method silica (Leosil) Glossy paper for ink jet recording was prepared under the same conditions as described in Example 1 except that 80.0 parts (QS-30, BET specific surface area 300 m ² / g: manufactured by Tokuyama Corporation).

(Example 16)
In Example 1, 70.0 parts of monodispersed spherical colloidal silica (Snowtex AK-YL, average particle size 120 nm: manufactured by Nissan Chemical Industries, Ltd.) and gas phase method silica (Leosil) Glossy paper for inkjet recording was produced under the same conditions as described in Example 1 except that 30.0 parts (QS-30, BET specific surface area 300 m ² / g: manufactured by Tokuyama Corporation).

(Comparative Example 1)
Example 1 is the same as Example 1 except that the coagulation liquid is an aqueous solution containing 1.0% boric acid and 1.0% sodium borate as the coagulant (the concentration of the coagulation liquid is 2.0%). Glossy paper for inkjet recording was produced under the conditions as described.

(Comparative Example 2)
In Example 1, 30.0 parts of monodispersed spherical colloidal silica (Snowtex 50, average particle size 30 nm: manufactured by Nissan Chemical Industries, Ltd.) and gas phase method silica (Leolosil QS-) Glossy paper for ink-jet recording was prepared under the same conditions as described in Example 1 except that the content was 70.0 parts (30, BET specific surface area 300 m ² / g: manufactured by Tokuyama Corporation).

(Comparative Example 3)
In Example 1, 30.0 parts of monodispersed spherical colloidal silica (MP-4540M, average particle size 450 nm: manufactured by Nissan Chemical Industries, Ltd.) and gas phase method silica (Leolosil QS-) Glossy paper for ink-jet recording was prepared under the same conditions as described in Example 1 except that the content was 70.0 parts (30, BET specific surface area 300 m ² / g: manufactured by Tokuyama Corporation).

(Comparative Example 4)
As described in Example 1, except that the pigment of the coating liquid for glossy layer in Example 1 was 100 parts of monodispersed spherical colloidal silica (Snowtex AK-YL, average particle size 120 nm: manufactured by Nissan Chemical Industries, Ltd.). Glossy paper for inkjet recording was prepared under the same conditions.

(Comparative Example 5)
In Example 1, it was described in Example 1 except that the pigment of the coating liquid for the glossy layer was 100 parts by vapor phase method silica (Leosil QS-30, BET specific surface area 300 m ² / g: manufactured by Tokuyama Corporation). A glossy paper for ink-jet recording was produced under the same conditions.

(Comparative Example 6)
In Example 1, except that the pigment of the coating liquid for the glossy layer was 100 parts of alumina (TM-300, BET specific surface area 220 m ² / g, crystal form-γ type: manufactured by Daimei Chemical Co., Ltd.) A glossy paper for ink jet recording was produced under the conditions described in 1.

(Comparative Example 7)
In Example 1, non-spherical colloidal silica (snowtex PS-MO, primary particle diameter 18-25 nm, secondary particle diameter) in which a plurality of spherical colloidal silicas are connected in a pearl necklace shape as the pigment of the coating liquid for the glossy layer. 80 to 150 nm (manufactured by Nissan Chemical Industries, Ltd.) Glossy paper for ink-jet recording was produced under the same conditions as described in Example 1 except that 100 parts were used.

  The glossy paper for ink jet recording thus obtained was evaluated by the following method. The results are shown in Table 1 (Examples) and Table 2 (Comparative Examples).

(1) Friction coefficient on glossy layer surface:
The friction coefficient between the glossy expression layer surfaces of the obtained glossy paper for inkjet recording was measured. The coefficient of friction was measured according to JIS P 8147: 1994 “Method for testing coefficient of friction of paper and paperboard”. In addition, about the measurement surface of a test piece, it was set as the combination of glossy expression layers, and about the vertical and horizontal of paper, it was set as the combination of vertical and vertical. The static friction coefficient and the dynamic friction coefficient were determined by using a strograph (STROGRAPH-R2, manufactured by Toyo Seiki Co., Ltd.).

(2) Image clarity (image clarity) of the glossy layer surface:
In order to evaluate the specularity of the glossy layer surface of the obtained ink jet recording paper, image clarity was measured. The image clarity is in accordance with JIS H 8686-2: 1999 “Image quality test method for anodized films of aluminum and aluminum alloys—Part 2: Instrument measurement method” with an optical comb width of 2 mm and an incident reflection angle of 60 °. , And measured with an image clarity measuring device (ICM-1T: manufactured by Suga Test Instruments Co., Ltd.). The evaluation is as follows.
Image clarity is 50% or more: The reflected image is clearly visible, excellent in gloss, and practical.
Less than 50%: Reflected image is unclear, inferior in glossiness, and has a practical problem as glossy paper.

(3) Image clarity of dye ink:
An ISO standard image (ISO / JIS-SCID high-definition color digital standard image data, image name: portrait, image identification number: N1) was obtained using an ink jet printer “PM-T960” exclusively for dye ink manufactured by Seiko Epson Corporation. The ink jet recording paper was printed. The printed image was visually evaluated.
(Double-circle): The recorded image is very clear and contrast is clear, and it can be used practically.
○: The recorded image is clear and the contrast is clear, and can be used practically.
(Triangle | delta): The recorded image is clear, but contrast is not clear, the color is sinking, and there exists a problem in practical use.
X: The recorded image is unclear and the color is sinking, impractical.

(4) Absorbability of dye ink:
Each ink of CMYK, solid (100% density) of RGB (Red-Green-Blue), and characters were printed on the ink jet recording paper obtained by using an ink jet printer “PM-T960” exclusively for dye ink manufactured by Seiko Epson Corporation. The boundary of each color of the solid portion and the degree of blurring of the characters were evaluated visually.
(Double-circle): The boundary is clear, there is no blur, a character is clear, and it can be used practically.
○: The blurring of the boundary is not conspicuous and the characters are clear and practical.
(Triangle | delta): The blur of a boundary is conspicuous, a character is unclear, and there exists a problem practically.
X: The blurring of the boundary is severe, and the character cannot be identified, so that it is not practical.

(5) Image clarity of pigment ink:
An ISO standard image (ISO / JIS-SCID high-definition color digital standard image data, image name: portrait, image identification number: N1) was obtained using an ink jet printer “PX-G900” exclusively for pigment ink manufactured by Seiko Epson Corporation. The ink jet recording paper was printed. The printed image was visually evaluated.
(Double-circle): The recorded image is very clear and contrast is clear, and it can be used practically.
○: The recorded image is clear and the contrast is clear, and can be used practically.
(Triangle | delta): The recorded image is clear, but contrast is not clear, the color is sinking, and there exists a problem in practical use.
X: The recorded image is unclear and the color is sinking, impractical.

(6) Absorption of pigment ink:
Using an ink jet printer “PX-G900” exclusively for pigment ink manufactured by Seiko Epson Corporation, each ink of CMYK, solid (100% density) of RGB (Red-Green-Blue), and characters were printed on the obtained ink jet recording paper. The boundary of each color of the solid portion and the degree of blurring of the characters were evaluated visually.
(Double-circle): The boundary is clear, there is no blur, a character is clear, and it can be used practically.
○: The blurring of the boundary is not conspicuous and the characters are clear and practical.
(Triangle | delta): The blur of a boundary is conspicuous, a character is unclear, and there exists a problem practically.
X: The blurring of the boundary is severe, and the character cannot be identified, so that it is not practical.

(7) Scratch resistance on the surface of the glossy layer:
Inkjet recording obtained using an ISO standard image (ISO / JIS-SCID high-definition color digital standard image data, image name: portrait, image identification number: N1) using an inkjet printer “Photosmart C5380” manufactured by Hewlett-Packard Company The degree of scratches on the surface of the glossy layer when printed on paper was visually evaluated.
(Double-circle): There is no scratch and it is favorable and can be used practically.
○: Scratches are slightly recognized but are not noticeable and can be used practically.
Δ: Scratches are clearly recognized, and there is a problem in practical use.
X: Scratches are remarkably recognized and impractical.

  As is apparent from Table 1, Examples 1 to 16 are superior to Comparative Examples 1 to 7 in the ink absorbability and image sharpness of the dye ink and the pigment ink, and the glossiness of the glossy surface, and exhibit gloss. The layer was excellent in scratch resistance.

  In Comparative Example 1, both the higher fatty acid salt as the lubricant and the polyethylene emulsion were not included in the glossy layer, and thus the scratch resistance was poor. In Comparative Example 2, since the average particle size of the monodispersed spherical colloidal silica that is the pigment of the glossy layer was less than 50 nm, the glossy layer was inferior in scratch resistance. Comparative Example 3 was inferior in pigment ink suitability because the average particle size of monodispersed spherical colloidal silica, which is a pigment of the glossy layer, exceeded 300 nm. Comparative Example 4 was inferior in pigment ink suitability because the pigment in the glossy layer did not contain vapor phase silica. In Comparative Example 5, since the monodisperse spherical colloidal silica was not contained in the pigment of the glossy layer, the glossy layer was inferior in scratch resistance. Since Comparative Examples 6 and 7 did not contain monodispersed spherical colloidal silica and gas phase method silica as the pigment of the glossy expression layer, the suitability of dye ink and pigment ink and the scratch resistance of the glossy expression layer could not be compatible.

Claims (8)

One or more ink receiving layers are provided on at least one side of the paper substrate, and a glossy expression layer containing a pigment, a binder and a lubricant is provided on the outermost layer of the ink receiving layer by a cast coating method. Inkjet recording glossy paper,
The gloss developing layer contains gas phase method silica and monodispersed spherical colloidal silica as the pigment, and contains a higher fatty acid salt and a polyethylene emulsion as the lubricant, and the monodispersed spherical colloidal silica A glossy paper for ink-jet recording, having an average particle diameter of 50 to 300 nm.   2. The glossy paper for ink-jet recording according to claim 1, wherein a mass ratio of the monodispersed spherical colloidal silica and the gas phase method silica is 20/80 to 70/30. The glossy paper for ink-jet recording according to claim 1, wherein the vapor phase silica has a BET specific surface area of 200 to 400 m ² / g.   The cast coating method for forming the glossy expression layer is a coagulation method, and the coagulation liquid contains a higher fatty acid salt and a polyethylene emulsion as the lubricant. The glossy paper for inkjet recording as described in any one.   The glossy layer contains at least one of laurate, myristate, and oleate as the higher fatty acid salt, according to any one of claims 1 to 4. Glossy paper for inkjet recording.   The glossy layer contains silanol-modified polyvinyl alcohol as the binder, and the content of the silanol-modified polyvinyl alcohol is 1 to 10 parts by mass with respect to 100 parts by mass of the pigment contained in the glossy layer. The glossy paper for ink-jet recording according to any one of claims 1 to 5, wherein the glossy paper is a mass part.   The glossy paper for ink-jet recording according to any one of claims 1 to 6, wherein the coagulation liquid contains one or both of sodium borate and boric acid as a coagulant. Inkjet in which at least one ink receiving layer is provided on at least one side of a paper substrate, and a glossy expression layer containing a pigment, a binder and a lubricant is provided on the outermost layer of the ink receiving layer by a cast coating method. A method for producing glossy paper for recording, comprising:
Glossy expression wherein gas phase method silica and monodispersed spherical colloidal silica and a binder are contained as a pigment on the outermost layer of the ink receiving layer, and the average particle diameter of the monodispersed spherical colloidal silica is 50 to 300 nm. A step of applying a layer coating liquid;
While the obtained coated surface is in a wet state, a coagulant and the lubricant are contained, and the lubricant is applied to the coated surface with a coagulating liquid containing a higher fatty acid salt and a polyethylene emulsion. A method for producing glossy paper for ink-jet recording, comprising the steps of: coagulating and pressurizing to a heated mirror-finished metal surface and drying to form a glossy layer.