JP2011073369A - Method for manufacturing inkjet recording paper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an ink jet recording paper, which is inexpensive and has the same level of glossiness as that of silver salt photograph by efficiently forming a glossy layer including colloidal silica therein to develop glossiness. <P>SOLUTION: An ink absorbing layer is provided on at least one surface of a support body with air permeability. Aqueous solution containing boric acid and/or pyroborate, for example, is coated on the ink absorbing layer and then a coating liquid consisting mainly of colloidal silica is applied on the ink absorbing layer in a wet condition. Then, the ink absorbing layer is pressure bonded onto the mirror surface drum of a high temperature, thereby forming a glossy layer on the uppermost surface thereof to manufacture the ink jet recording paper. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an ink jet recording paper applied to an ink jet recording system.

  Inkjet recording, which forms an image on recording paper by ejecting water-based ink or pigment ink in which colorant is dispersed from fine nozzles, is superior in cost performance in full-color printing and is capable of high-speed recording. Is installed and used in various devices that require

  On the other hand, with the widespread use of digital cameras and high-definition inkjet recording methods, photo output by inkjet recording methods is increasing instead of conventional silver salt photography. Photographic ink jet recording paper is required to have excellent image reproducibility and ink absorbability, high smoothness, glossiness, storage stability, and the like.

  Inkjet recording paper for photography is coated with an ink absorbing layer containing fine particles to absorb ink printed on a support, and the ink absorbing layer is high while absorbing and holding ink. Since it is necessary to have color developability and be clear, high transparency is required. Furthermore, in order to give the coating layer a high glossiness equivalent to or higher than that of silver salt photographic paper, it is common to produce a glossy layer by a cast coating method to produce a photographic inkjet paper. In the cast coating method, a coating liquid mainly composed of a pigment and a binder is applied onto a base paper to provide a coating layer, and the coating layer is pressed against a mirror-finished heating drum. This is a copy method. The cast coating method includes (1) a wet casting method (direct method) in which a coating layer is pressed onto a mirror-finished heating drum while the coating layer is wet, and (2) a wet coating layer is once dried. Alternatively, a semi-dried, rewetting method that is swollen and plasticized with a re-wetting solution, and is pressed onto a mirror-finished heating drum and dried. (3) A heated coating drum that is mirror-finished after the wet coating layer is gelled by coagulation There are generally known three types of gelation cast methods (coagulation methods) in which pressure is bonded to the substrate and dried. The principle of each method is the same in that the wet coating layer is pressed against the mirror-finished surface to give gloss to the coating layer surface. The photographic inkjet recording paper thus obtained has a smooth surface and gloss, and can be used as an alternative to conventional silver salt photography.

  On the other hand, with the spread of digital cameras in recent years, output from home inkjet printers or business terminals has increased, and the opportunity to output photographic images has increased. Against this background, there is a demand for price reduction of photographic inkjet recording paper.

  On the other hand, photographic ink jet recording paper is required to hold ink in a recording layer, have good color development and good sharpness, so that the recording layer must be porous and transparent. Is done. For these reasons, aluminum compounds such as alumina hydrate and alumina sol as proposed in Patent Document 1 have been proposed and widely used. However, the alumina compound is expensive and expensive to use as the main component of the pigment in the ink jet recording layer, and is currently a material that does not meet the product price required by the market.

  In recent years, inkjet recording papers on the market have shifted from products that use the main component of pigments to expensive aluminum compounds to products that use inexpensive silica as the main component of pigments. In order to absorb ink, wet silica or gas phase method silica having a large specific surface area is used, and colloidal silica is used for glossiness. The ink absorption layer contains wet silica or gas phase method silica having a large specific surface area as a main component, and the gloss layer is a coating layer containing colloidal silica in addition to the silica. More ideally, the outermost layer is a coating layer for expressing gloss, and the main component may be colloidal silica, and a coating layer having high absorbability for absorbing ink is desired below the coating layer. Rarely, it is considered that each coating layer has a function.

  In order to form the gloss layer having excellent transparency and gloss, the relatively expensive colloidal silica must be used among the silicas proposed in Patent Document 2. In particular, when it is used on the outermost surface as a glossy layer in an inkjet recording paper having a multilayer structure as proposed in Patent Document 3, a certain amount of coating is required, resulting in high costs.

  In addition, when two or more layers for absorbing ink are provided on a gas-permeable support and at least one gloss layer that exhibits gloss is provided, the coating must be applied at least twice. Therefore, it becomes complicated and the manufacturing cost increases.

Japanese Patent No. 3025773 Japanese Unexamined Patent Publication No. 7-117335 JP 2006-240075 A

  An object of the present invention is to provide an ink jet recording paper having a function as an ink jet recording paper on at least one of the supports and having a gloss feeling equivalent to that of a silver salt photograph. Furthermore, the present invention provides an inexpensive product by efficiently forming a gloss layer containing an expensive colloidal silica that expresses the gloss used at that time.

  As a result of intensive studies by the inventors to provide the above-described inkjet recording paper, an ink absorbing layer is provided on at least one surface of a gas-permeable support, and the ink absorbing layer is in a wet state After applying the coating liquid containing colloidal silica as a main component, press the high pressure mirror drum to form a glossy layer on the outermost surface, so that both the ink absorption layer and the glossy layer can be applied in a single step. The manufacturing method formed simultaneously was discovered. Preferably, at least one surface of the air-permeable paper is coated with an ink-absorbing layer coating containing wet silica and vapor-phase silica as the main components and polyvinyl alcohol as the binder, and boric acid or A coagulating liquid containing sodium borate is applied to gel the paint of the ink absorbing layer. Then, after the excess coagulating liquid on the gelled ink absorbing layer was wiped off with an air knife or the like, the nip was formed when the ink absorbing layer was wet and pressed with an elastic roll to a high-temperature mirror drum. A paint for forming a gloss layer mainly composed of colloidal silica is dropped or poured into the region from above, and the ink absorption layer and the high-temperature mirror drum are pressed together to copy the mirror surface and simultaneously dry the coating layer.

  The ink jet recording paper produced by this production method is very excellent in cost and has high gloss.

  The photographic inkjet recording paper produced in the present invention can form an ink absorbing layer and a glossy layer in a single step. In addition, expensive colloidal silica with excellent glossiness can be placed on the most efficient surface to achieve its effect, so there is no need for excessive compounding, low manufacturing costs, and high gloss. It is possible to provide an ink jet recording paper having the property.

<Support>
There are no particular restrictions on the type, shape, dimensions, etc. of the support used for the inkjet recording paper, but an absorbent support having air permeability is desirable.
<Absorptive support>
As the absorbent support, for example, paper such as coated paper and non-coated paper can be suitably used. The main components of paper are pulp and internal filler. As the pulp, any known pulp can be used. For example, hardwood bleached kraft pulp, hardwood unbleached kraft pulp, softwood bleached kraft pulp, softwood unbleached kraft pulp, hardwood bleached sulfite pulp, hardwood unbleached sulfite pulp, softwood bleached sulfite pulp, softwood unbleached sulfite pulp, wood Pulp made by chemically treating fiber raw materials such as cotton, hemp, and leather can be used. In addition, ground wood pulp that mechanically pulped wood and chips, chemimechanical pulp mechanically pulped after soaking chemicals into wood and chips, and pulp with a refiner after the chips are digested until they are slightly soft Thermomechanical pulp that has been made into a material can also be used.

  Pulp made from used paper, that is, cuts that occur in bookbinding, printing plants, cutting offices, damaged paper, narrow whites, whites, whites, whites, whites, etc. High-quality printed paper such as high-quality paper, high-quality coated paper that has been copied; old paper written with water-based ink, oil-based ink, pencil, etc .; printed high-quality paper, high-quality coated paper, medium-quality paper, medium-quality coated paper, etc. It is also possible to use pulp obtained by disaggregating old paper such as medium-sized paper, medium-coated paper, and reprinted paper. It is preferable to use hardwood bleached kraft pulp having high whiteness and excellent texture for the inkjet paper.

  The pulp can be made high white by bleaching. Pulp bleaching methods include chlorine bleaching using a combination of chemicals such as elemental chlorine, hypochlorite, chlorine dioxide, oxygen, hydrogen peroxide, caustic soda, bleaching method using chlorine dioxide (ECF), There is a method called bleaching (TCF) in which ozone / hydrogen peroxide is mainly used without using any chlorine compound. Of these, it is preferable that bleaching is performed by a method such as ECF or TCF since the load of an organic chlorine compound formed by a chlorine bleaching method may adversely affect the environment. Further, in ECF, chlorine dioxide reacts selectively with lignin, so that the whiteness of the pulp can be increased without damaging the cellulose, which is more preferable.

For the purpose of improving the opacity and whiteness of the support, a filler may be contained (internally added). For the internal filler, white pigments such as clay, kaolin, talc, heavy calcium carbonate, light calcium carbonate, barium sulfate, titanium oxide, aluminum hydroxide, magnesium hydroxide can be used, but high whiteness is easily obtained. To calcium carbonate, and in particular rosette type light calcium carbonate. Rosetta-type light calcium carbonate is obtained by agglomerating primary particles of spindle-shaped light calcium carbonate in a radial manner to form Rosetta-type secondary particles. Specifically, Specialty Minerals Inc. Products such as Albuquer HO, Albuquer 5970, Albuquer LO, etc. can be preferably mentioned. Here, the term “radial” refers, for example, to the longitudinal direction of each primary particle extending radially from the vicinity of the center of the secondary particle. The density of the base paper is preferably 0.8 g / cm ³ or less.

  The pulp is beaten by a beating machine such as a double disc refiner in order to improve paper properties such as papermaking suitability, strength, smoothness, and uniformity of formation. The degree of beating can be selected according to the purpose within a normal range of about 250 ml to 550 ml in Canadian Standard Freeness (C.S.F.). The pH of the pulp may be acidic, neutral or alkaline.

  The beaten pulp slurry can be made by a paper machine such as a long net paper machine, a twin wire paper machine, or a round net paper machine to obtain a support. In this case, the pulp slurry usually used for paper making is used. It is possible to add a dispersion aid, a dry paper strength enhancer, a wet paper strength enhancer, a sizing agent, a fixing agent, a pH adjuster, a dye, a colored pigment, a fluorescent whitening agent, and the like.

  As the dispersion aid, for example, polyethylene oxide, polyacrylamide, toro-blue and the like are used. Examples of the paper strength enhancer include anionic paper strength enhancers such as vegetable gum, starch and carboxy-modified polyvinyl alcohol, and cationic paper strength enhancers such as cationized starch, cationic polyacrylamide and polyamide polyamine epichlorohydrin resin. Used. Examples of the sizing agent include higher fatty acid salts, rosin derivatives such as rosin and maleated rosin, dialkyl ketene dimers, alkenyl or alkyl succinates, epoxidized fatty acid amides, polysaccharide esters and the like. Examples of the fixing agent include polyvalent metal salts such as aluminum sulfate and aluminum chloride, cationic polymers such as cationized starch and polyamide polyamine epichlorohydrin resin. Examples of the pH adjuster include hydrochloric acid, caustic soda, sodium carbonate, and the like.

  In addition, for the support, a coating liquid containing various additives including a water-soluble polymer additive is used on-machine or by using a tab size, a size press, a gate roll coater, a film transfer coater, or the like. It can be applied off-machine.

  Examples of the water-soluble polymer additive include starch derivatives such as starch, cationized starch, oxidized starch, etherified starch, and phosphate esterified starch; polyvinyl alcohol derivatives such as polyvinyl alcohol and carboxy-modified polyvinyl alcohol; carboxymethylcellulose Cellulose derivatives such as hydroxymethyl cellulose, hydroxyethyl cellulose, cellulose sulfate; water-soluble natural polymers such as gelatin, casein, soybean protein; sodium polyacrylate, sodium styrene-maleic anhydride copolymer, sodium polystyrene sulfonate, etc. Water-soluble polymers such as maleic anhydride resins; aqueous polymer adhesives such as thermosetting synthetic resins such as melamine resins and urea resins are used. Other additives include petroleum resin emulsion, styrene-maleic anhydride copolymer alkyl ester ammonium salt, alkyl ketene dimer emulsion, styrene-butadiene copolymer, ethylene-vinyl acetate copolymer, polyethylene as sizing agent. And dispersion such as polyvinylidene chloride. Examples of other additives include sodium chloride, calcium chloride, and bow glass that are inorganic electrolytes as antistatic agents, and glycerin, polyethylene glycol, and the like as hygroscopic substances. Examples of other additives include clay, kaolin, talc, calcium carbonate, silica, barium sulfate, and titanium oxide as pigments. As other additives, hydrochloric acid, caustic soda, sodium carbonate, etc. are used as pH adjusters, and other additives such as dyes, fluorescent brighteners, antioxidants, ultraviolet absorbers, etc. can be used in combination. is there.

<About ink absorbing layer>
By forming an ink absorbing layer on the support, it is possible to suitably adjust the absorptivity of ink when printed by an ink jet printer, and there is a tendency to improve the printability such as print density, print bleeding, and solid uniformity. . The ink absorption layer is a layer having a function of quickly absorbing the solvent component of the ink, and mainly includes a pigment and a binder. In order to absorb ink more effectively, two or more ink absorption layers may be provided. However, for the purpose of efficient production for the purpose of the present invention, the ink absorption layer should be a single layer. Is desirable.

(About pigments in ink absorption layer)
As the pigment blended in the ink absorbing layer, known inorganic fine particles and organic fine particles can be used. For example, kaolin, clay, calcined clay, amorphous silica (also called amorphous silica), synthetic amorphous silica, zinc oxide, aluminum oxide, titanium oxide, aluminum hydroxide, alumina hydrate (alumina sol, colloidal alumina, Pseudoboehmite, etc.), alumina (α type crystal alumina, θ type crystal alumina, γ type crystal alumina, etc.), calcium carbonate, satin white, aluminum silicate, alumina, colloidal silica, zeolite, synthetic zeolite, sepiolite, smectite, Synthetic smectite, magnesium silicate, magnesium carbonate, magnesium oxide, diatomaceous earth, styrene plastic pigment, hydrotalcite, urea resin plastic pigment, benzoguanamine plastic pigment, etc. The various pigments one or more may be used in combination. Among these, zinc oxide, titanium oxide, and plastic pigments are preferably blended because yellowing of the white paper portion can be prevented. Amorphous silica, alumina, and zeolite are preferably contained as a main component because they have high ink absorbability. In particular, colloidal silica is preferably included in the pigment from the viewpoint of color developability, from the viewpoint of ink absorbability and cost. It is preferable to include synthetic amorphous silica in the pigment.

The synthetic amorphous silica can be roughly classified into wet method silica and gas phase method silica depending on the production method. Synthetic amorphous silica produced by a wet process is inferior to gas phase process silica in pigment transparency, but is excellent in paint stability when used in combination with polyvinyl alcohol. Furthermore, wet process silica has better dispersibility than gas phase process silica without internal voids, and can increase the coating concentration. Therefore, the ratio of the pigment (to the binder) in the ink absorbing layer can be increased, and the ink absorbability can be improved and the color developability of the dye ink can be improved. The secondary particle diameter of the wet process silica is preferably 1 to 5 μm and the BET specific surface area is preferably 150 to 500 m ² / g from the viewpoint of obtaining high gloss. Moreover, it is preferable that the primary particle diameter of the said vapor phase method silica is 5 nm-70 nm from a point of obtaining a coating layer with high transparency, and it is preferable that a BET specific surface area is 30-500 m < ² > / g. When two or more kinds of pigments having different average particle diameters are used as the pigment of the ink absorption layer, the “average particle diameter of the pigment” is a value obtained by weighted averaging the average particle diameter of each pigment by the content ratio of each pigment. To do. The average particle diameter of the pigment in the ink absorbing layer is preferably 1 to 5 μm. If it is smaller than 1 μm, the ink absorbency is inferior, and if it exceeds 5 μm, the glossiness tends to decrease.

(Binder for ink absorbing layer)
An aqueous binder resin can be used as a binder for the ink absorbing layer. “Aqueous” means that the resin is dissolved or dispersed and stabilized (water-soluble or / and water-dispersible resin emulsion) in water or a medium composed of water and a small amount of an organic solvent. The aqueous binder resin means a water-soluble resin and a water-dispersible resin. The aqueous binder resin is dissolved or dispersed in the coating liquid to be coated on the support, but after coating and drying, it becomes a binder for the pigment and forms an ink absorbing layer.

  Examples of the aqueous binder resin include polyvinyl alcohol and derivatives thereof; polyvinyl pyrrolidone; urethane resin derived from urethane resin emulsion; starches such as oxidized starch and esterified starch; cellulose derivatives such as carboxymethylcellulose and hydroxyethylcellulose; casein; gelatin; Examples include soybean protein; styrene-acrylic resin and derivatives thereof; styrene-butadiene resin latex; acrylic resin emulsion, vinyl acetate resin emulsion, vinyl chloride resin emulsion, urea resin emulsion, alkyd resin emulsion, and derivatives thereof. These aqueous binder resins can be used alone or in combination.

  In the present invention, it is preferable that polyvinyl alcohol is contained in the binder from the viewpoint of color development and cost, and partially saponified polyvinyl alcohol is particularly preferable. The amount of polyvinyl alcohol added is preferably 3 to 30 parts by mass with respect to 100 parts by mass of the total pigment in the ink absorbing layer. However, the type of the binder is not particularly limited as long as the required coating layer strength is obtained.

  The ink absorption layer contains the above-described pigment and binder, but other components such as a thickener, an antifoaming agent, an antifoaming agent, a pigment dispersant, a release agent, a foaming agent, a pH adjusting agent, a surface. Sizing agent, coloring dye, coloring pigment, fluorescent dye, ultraviolet absorber, antioxidant, light stabilizer, preservative, water resistance agent, dye fixing agent, surfactant, wet paper strength enhancer, water retention agent, cation In the range which does not impair the effect of this invention, an electroconductive polymer electrolyte etc. can be suitably added to the coating layer used as the precursor of an ink absorption layer.

  As a method of applying a coating liquid to be an ink absorbing layer on a support, blade coater, air knife coater, roll coater, brush coater, kiss coater, squeeze coater, curtain coater, die coater, bar coater, gravure coater, gate roll A known coating machine such as a coater or a short dwell coater can be appropriately selected from the coating methods used on-machine or off-machine.

The ink absorbing layer may be applied in two or more layers as required, but the coating amount of the ink absorbing layer coating solution is preferably ^{2 to} 60 g / m ² , more preferably in terms of dry mass. Is about ² to 30 g / m ² , more preferably about 4 to ²⁰ g / m ² . By setting the coating amount to 2 g / m ² or more, the effect of improving ink absorbency can be sufficiently obtained, and excellent gloss can be obtained when an ink absorption layer is provided, and by setting it to 60 g / m ² or less. The printing density is increased, the strength of the coating layer is improved, and there is a tendency that powder falls and scratches are less likely to occur.

  In the present invention, when a large coating amount of the ink absorbing layer is required, the ink absorbing layer can be formed in multiple layers. Further, an undercoat layer having various functions such as ink absorptivity, adhesiveness and the like may be provided between the support and the ink absorbing layer. Further, a back coat layer having various functions such as ink absorbability, writing ability, printer printability and the like may be further provided on the side opposite to the surface provided with the ink absorption layer.

[About coagulants]
Examples of the coagulant having an action of gelation upon contact with the coating liquid forming the ink absorbing layer include boron compounds, epoxy compounds, glycidyl compounds, zirconium compounds, aluminum compounds, chromium compounds and the like. Among these, when combined with the polyvinyl alcohol used as the above-mentioned binder, a boron compound is preferable, and boric acid, borax, or a mixture thereof is preferable because the gelation proceeds rapidly. Examples of boric acid include orthoboric acid, metaboric acid, hypoboric acid, tetraboric acid, and pentaboric acid. In addition, a water-soluble metal salt, a water-soluble resin, a water-soluble emulsion, a dye, a release agent, and the like can be added to the coagulant liquid.

<About glossy layer>
The coating liquid for forming the gloss layer is mainly composed of colloidal silica for expressing gloss. Furthermore, the use of colloidal silica having a primary particle size of 20 to 70 nm is more preferable in terms of improving glossiness and suppressing printing unevenness during pigment ink printing. When the primary particle size of the colloidal silica is less than 20 nm, the transparency of the gloss layer is increased, but the ink absorbability is lowered, and the print quality may be lowered.

  On the other hand, the larger the primary particle size, the better the ink absorptivity, but if it exceeds 70 nm, the transparency of the ink absorbing layer is lowered, the printing density at the time of printing the dye ink is lowered, and the dye ink suitability may be inferior. . In addition to colloidal silica, water-soluble metal salts, water-soluble resins, water-soluble emulsions, dyes, and the like can be added.

The coating amount of the gloss layer is preferably 1 to 10 g / m ² in terms of solid content. When the coating amount is less than 1 g / m ² , gloss may be insufficiently imparted. On the other hand, even if the coating amount exceeds 10 g / m ² , the gloss improvement effect reaches its peak.

  Specifically, the glossy layer of the present invention is provided by applying a coating for an ink absorbing layer on an air permeable support to provide an ink absorbing layer, and applying a coagulant liquid on the ink absorbing layer. When the ink absorbing layer is gelled, excess coagulating liquid on the gelled ink absorbing layer is removed with an air knife or the like, and then the ink absorbing layer is wet and is pressure-bonded to a high-temperature mirror drum with an elastic roll. In the nipped area, a paint that forms a gloss layer mainly composed of colloidal silica is dropped or poured from above, and is pressed onto a high-temperature mirror drum (roll) together with the ink absorption layer, so that the mirror surface is copied and gloss is obtained at the same time. It is provided by drying the layer and the ink absorbing layer. The method for dropping the paint for the gloss layer is not particularly limited, but a method that allows dripping the paint for the gloss layer in an appropriate amount is desirable because a method of severe scattering causes a problem of work efficiency. In particular, dropping by a thin liquid film by curtain coating, dropping by a shower-like shape, and the like are preferable.

  The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to these examples. “Part” and “%” represent “part by mass” and “% by mass”, respectively, unless otherwise specified.

[Example 1]
Rosetta-type light calcium carbonate (Albuquer 5970: SMI) as a filler to a mixed pulp slurry of Canadian standard freeness 350 ml consisting of 90 parts of hardwood bleached kraft pulp (L-BKP) and 10 parts of softwood bleached kraft pulp (N-BKP) Product) was added so as to have an ash content of 20%, and 1.0 part of aluminum sulfate, 0.15 part of alkyl ketene dimer (AKD), and 0.05 part of a yield improver were added. The slurry is used to make a paper with a paper machine, and at this time, a surface size coating solution containing starch having a solid content concentration of 5% and a surface sizing agent (AKD) having a solid content concentration of 0.2% is obtained in a solid content of 1. the coating is 5 g / ^{m 2,} to obtain a support of 180 g / ^{m 2.}
The following coating liquid A for the ink absorbing layer was applied to this support by a roll coater so that the coating amount was 13 g / m ^{2 in} terms of solid content, and while the coating layer was in a wet state, The coating liquid B (coagulant liquid) is applied and solidified to a coating amount of 2.0 g / m ² in solid content, and then heated to a mirror-finished roll heated by a press roll covered with an elastic body. The following coating liquid (C) for the glossy layer was dropped onto the part to be pressed, pressed onto a mirror-finished roll surface heated through a press roll, and the mirror surface was copied and dried. By this production method, an ink jet recording paper having a basis weight of 195 g / m ² and a gloss of 20% specified by JIS Z 8741 of 31% and 75 ° gloss of 85% was prepared.
<Coating liquid A (ink absorbing layer coating liquid)>
Wet method synthetic amorphous silica (fine seal X-37B: manufactured by Tokuyama Co., Ltd., average secondary particle size 2.6 μm) as pigment, 100 parts of polyvinyl alcohol (PVA217: manufactured by Kuraray Co., Ltd.), fluorescent A coating solution having a concentration of 20% was prepared by blending 1.5 parts of a dye (BLANKOPHOR P liquid01: manufactured by LANXESS) and 0.5 part of a release agent (SN coating 289: manufactured by San Nopco). An aqueous ammonia solution was used for final pH adjustment.
<Coating liquid B (coagulant liquid)>
A coagulant (aqueous solution) containing 4% boric acid, 4% borax, and 0.5% release agent (PEM-17: manufactured by San Nopco) was prepared.
<Coating fluid C (Glossy layer coating fluid)>
Colloidal silica (ST-AK-L: manufactured by Nissan Chemical Co., Ltd.) 7% and release agent (PEM-17: manufactured by San Nopco) 0.5% were prepared.

[Example 2]
SI-50 (catalyst conversion) was used for the colloidal silica of the coating liquid C. Others were produced in the same manner as in Example 1, and an ink jet recording paper having a basis weight of 195 g / m ² and a gloss of 20 ° gloss specified by JIS Z 8741 of 30% and 75 ° gloss of 78% was prepared. did.

[Comparative Example 1]
Rosetta-type light calcium carbonate (Albuquer 5970: manufactured by SMI) as a filler for a pulp slurry having a beating degree of 350 ml comprising 90 parts of hardwood bleached kraft pulp (L-BKP) and 10 parts of softwood bleached kraft pulp (N-BKP) Was added to an ash content of 20%, and 1.0 part of aluminum sulfate, 0.15 part of AKD, and 0.05 part of a yield improver were added. Using this slurry, a paper machine was used to make paper, and at that time, 5% starch and 0.2% surface sizing agent (AKD) were applied to a solid content of 1.5 g / m ^2, and 180 g / m ² was applied. A support of m ² was obtained.
The coating liquid (A) for the ink absorbing layer is applied to this support with a roll coater so that the coating amount is 13 g / m ² in solid content, and the coating layer is applied while the coating layer is in a wet state. The liquid (B) is applied and solidified so as to have a coating amount of 2.0 g / m ² as a solid content, and then pressed onto a mirror-finished roll heated with a press roll covered with an elastic body to copy the mirror surface. At the same time, it was dried. By this production method, an ink jet recording paper having a basis weight of 195 g / m ² and a gloss of 20 ° gloss specified by JIS Z 8741 of 15% and 75 ° gloss of 58% was prepared.

(Evaluation)
1. Evaluation of output image by inkjet recording method A predetermined digital photograph was output to the obtained inkjet recording medium using a dye inkjet printer (PM-970C: manufactured by Epson Corporation). Images of the ink-jet photographic paper based on resin-coated paper were compared and evaluated.

○: Almost no difference from inkjet photographic paper Δ: Slightly inferior to inkjet photographic paper ×: 2.20 ° glossiness, 75 ° glossiness clearly inferior to inkjet photographic paper 20 ° glossiness of the obtained inkjet recording paper, The 75 ° gloss was measured according to JIS-Z8741 using a gloss meter (manufactured by Murakami Color Research Laboratory, True GLOSS GM-26PRO).

  The obtained results are shown in Table 1.

  The inkjet recording papers of Examples 1 and 2 produced by the method of the present invention had high gloss. On the other hand, the glossiness of the inkjet recording paper of Comparative Example 1 was low.

Claims (3)

  An ink absorbing layer is provided on at least one surface of a gas-permeable support, and a coating liquid mainly composed of colloidal silica is applied in a state where the ink absorbing layer is in a wet state. A method for producing an ink jet recording paper, characterized in that a gloss layer is formed on the outermost surface by pressure bonding.   After applying an aqueous solution containing boric acid and / or borax on the ink absorbing layer in a state where the ink absorbing layer is provided in a wet state on at least one surface of a support having air permeability 2. A method for producing an ink jet recording paper according to claim 1, further comprising: applying a coating liquid containing colloidal silica as a main component and then press-bonding to a high temperature mirror drum to form a glossy layer on the outermost surface. .   An ink absorbing layer is provided on at least one surface of a gas-permeable support, and a coating liquid mainly composed of colloidal silica is applied in a state where the ink absorbing layer is in a wet state. An inkjet recording paper, characterized in that a gloss layer is formed on the outermost surface by pressure bonding.