JP2009127132A - Method for producing recording medium, recording medium, and inkjet recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a recording medium by which the recording medium enabling high-quality printing to be carried out at a low cost and a high speed, and the adherence between a first layer and a second layer can be improved, and to provide the recording medium and an inkjet recording method. <P>SOLUTION: The method for producing the recording medium includes a first coating step for coating a first coating liquid for forming the first layer on a base paper, a drying step for continuously drying the coated first coating liquid after the first coating step by introducing the coated product to a hot air drier group, and a second coating step for continuously coating a second coating liquid for forming the second layer on the dried first coating liquid after the drying step. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a recording medium manufacturing method, a recording medium, and an ink jet recording method.

  The ink jet apparatus has a simple configuration, and high-quality image recording can be performed by ink jet recording performed using the ink jet apparatus. Ink used in inkjet recording is designed to have a viscosity of about several mPa · s to 30 mPa · s and a surface tension of about 20 mN / m to 40 mN / m so that the ink can be ejected from the inkjet head.

  Usually, the ink contains 50 wt% to 90 wt% ink solvent so that the viscosity of the ink falls within the above range. As the ink solvent, water, an organic solvent, oil, a photopolymerizable monomer, and the like are used. In particular, water is frequently used from the viewpoint of environmental suitability. In addition, the ink solvent generally contains a high-boiling solvent such as glycerin so that the discharge nozzle of the ink jet head does not cause clogging due to drying of the ink solvent.

  On the other hand, image blur due to a large amount of ink solvent and color mixing between colors occur in a recording medium on which ink is drawn. For this reason, image blurring or color mixing between colors occurs when an ink jet exclusive paper (FIG. 5) having a solvent absorbing layer (ink receiving layer) of about 20 to 30 μm on the surface for absorbing the ink solvent is used as a recording medium. Is suppressed.

  Further, in the case of water-based ink using water as an ink solvent, paper permeation such as curl or cockle occurs when water penetrates into the base paper during recording. However, as shown in FIG. When the solvent absorption layer 22 is formed on the paper, it is possible to suppress the penetration of water into the base paper and suppress the paper deformation.

On the other hand, when forming a graphical image with high image density and image area ratio, the amount of ink per unit area on the recording medium increases, and the solvent absorption layer cannot suppress the penetration of the ink solvent into the base paper. Therefore, water-resistant paper (for example, laminate paper) including a water-resistant layer such as a polyolefin layer is used (see, for example, Patent Documents 1 and 2).
Further, as a recording medium provided with at least two or more coating layers on one side or both sides of the base paper, a latex binder is contained in the lowermost coating layer, the latex binder has a gel content of 65% or less, an average grain A recording medium having a diameter of 100 to 250 nm is disclosed (for example, see Patent Document 3).

Ink jet technology has been applied to fields such as office printers and home printers, but has recently been applied in the field of commercial printing. This commercial printing field does not have a photo-like surface that completely shuts out the penetration of the ink solvent into the base paper, but requires a printing texture like general-purpose printing paper. Here, when the solvent absorption layer in the recording medium is as thick as 20 to 30 μm, the surface gloss, texture, stiffness, etc. of the recording medium are limited. However, it is limited to posters, form printing, and the like that are allowed to be restricted in terms of surface gloss, texture, stiffness, etc. Further, the recording medium has a high cost due to the solvent absorption layer and the water resistant layer, which also contributes to the above limitation.
Patent Document 4 discloses a technique for controlling the time from performing surface printing to performing back surface printing to prevent bleeding on the back surface during double-sided printing. By simply controlling the time from printing to backside printing, it is not possible to prevent bleeding on the backside during double-sided printing, which requires heating.
As a conventional technique, a recording medium having a base paper, a blocking layer formed on the base paper, and an absorption layer formed on the blocking layer is not disclosed. When manufacturing this recording medium, the adhesion between the barrier layer and the absorbing layer has been a problem.

JP 2005-238829 A JP 2005-96285 A JP 2002-146697 A JP 2005-125750 A

  An object of the present invention is to solve the conventional problems and achieve the following objects. That is, the present invention can provide a recording medium that can perform high-quality printing at low cost and high speed, and can improve the adhesion between the first layer and the second layer. An object of the present invention is to provide a manufacturing method, a recording medium, and an inkjet recording method.

Means for solving the problems are as follows. That is,
<1> A base paper, a first layer containing a binder, and a second layer containing a white pigment are sequentially laminated, and the base paper provided with the first layer is water-absorbing as defined in JIS P8140. Cobb water absorption degree during a contact time 15 seconds by the time the test is at 5.0 g / ^{m 2} or less, the second layer, water absorption amount at a contact time of 0.5 sec determined by the Bristow method is 2 mL / ^{m 2} or more 8mL In the method for producing a recording medium of / m ² or less, a first coating step of applying a first coating liquid for forming the first layer on the base paper, and the first coating step Thereafter, the drying step of continuously introducing the coated first coating liquid into a hot air dryer group and drying, and the drying of the first coating continuously after the drying step A second coating step of coating a second coating liquid for forming the second layer on the liquid. Which is a method of manufacturing a recording medium characterized.
According to the method for producing a recording medium described in <1>, a recording medium capable of performing high-quality printing at low cost and at high speed can be obtained, and the first layer and the second layer can be obtained. Adhesion can be improved.
<2> The method for producing a recording medium according to <1>, wherein the first coating liquid dried in the drying step has a solid content concentration of 98% or less.
According to the method for producing a recording medium described in <2>, the adhesion between the first layer and the second layer can be improved.
<3> The method for producing a recording medium according to <2>, wherein the first coating liquid dried in the drying step has a solid content concentration of 80% or less.
According to the method for manufacturing a recording medium described in <3>, the adhesion between the first layer and the second layer can be improved.
<4> The method for producing a recording medium according to any one of <1> to <3>, wherein at least one of the first coating liquid and the second coating liquid contains a water-soluble binder.
According to the method for producing a recording medium described in <4>, the adhesion between the first layer and the second layer can be further improved, and the scratch resistance can be improved.
<5> The method for producing a recording medium according to <4>, wherein the water-soluble binder is at least one of polyvinyl alcohol and modified polyvinyl alcohol.
According to the method for producing a recording medium described in <5>, the adhesion between the first layer and the second layer can be further improved, and the scratch resistance can be improved.
<6> The method for producing a recording medium according to <5>, wherein the modified polyvinyl alcohol is acetoacetyl-modified polyvinyl alcohol having a polymerization degree of 1,000 or more.
<7> The method for producing a recording medium according to <5>, wherein the modified polyvinyl alcohol is silanol-modified polyvinyl alcohol.
<8> The recording medium according to any one of <4> to <7>, wherein at least one of the first coating liquid and the second coating liquid contains a crosslinking agent capable of crosslinking the water-soluble binder. It is a manufacturing method.
According to the method for producing a recording medium described in <8>, the adhesion between the first layer and the second layer can be improved, and the scratch resistance can be improved.
<9> In the step of applying a coating liquid containing a crosslinking agent capable of crosslinking the water-soluble binder, a crosslinking agent capable of crosslinking the water-soluble binder to the coating liquid immediately before coating the coating liquid. The method for producing a recording medium according to <8>, wherein the recording medium is added in-line.
According to the method for producing a recording medium described in <8>, the adhesion between the first layer and the second layer can be improved, the scratch resistance is improved, and the surface quality is improved. be able to.
<10> The method for producing a recording medium according to any one of <1> to <9>, wherein the second coating liquid is curtain-coated in the second coating step.
<11> The method for producing a recording medium according to any one of <1> to <10>, wherein the second coating liquid contains a nonionic surfactant.
According to the method for producing a recording medium described in <11>, the adhesion between the first layer and the second layer can be improved, and the surface quality and the image quality can be improved. .
<12> The method for producing a recording medium according to <11>, wherein the nonionic surfactant is an ethylene oxide adduct of a tertiary alcohol having an acetylene bond in the molecule.
<13> At least one of the first coating liquid and the second coating liquid contains an organic solvent, and the organic solvent has a solubility in pure water of 20 ° C. of 1% by mass or more and an SP value. Is 8.4 (cal / cm ³ ) ^{0.5 to} 13 (cal / cm ³ ) ^0.5 . The method for producing a recording medium according to any one of <1> to <12>.
According to the method for producing a recording medium described in <13>, the adhesion between the first layer and the second layer can be further improved.
<14> The method for producing a recording medium according to any one of <1> to <13>, wherein the base paper has a Steecht sizing degree defined in JIS P8140 of 30 seconds or more.
According to the method for manufacturing a recording medium described in <14>, curling can be suppressed.
<15> The base paper is a method for producing a recording medium according to any one of <1> to <14>, wherein the base paper contains 0.1 to 10 g / m ² of an antioxidant.
According to the method for producing a recording medium described in <15>, the image fastness can be improved and the scratch resistance can be maintained.
<16> A recording medium manufactured by the method for manufacturing a recording medium according to any one of <1> to <15>.
<17> An ink drawing process for drawing ink in accordance with predetermined image data on the recording medium according to <16>, and a dry removal process for drying and removing the ink solvent in the recording medium drawn with ink. An ink jet recording method comprising:

  According to the present invention, a method for producing a recording medium, recording which can solve the conventional problems, achieve the object, and improve the adhesion between the first layer and the second layer. A medium and an ink jet recording method can be provided.

  Hereinafter, a recording medium manufacturing method, a recording medium, and an inkjet recording method of the present invention will be described with reference to the drawings.

(recoding media)
The recording medium of the present invention includes a base paper, a first layer, and a second layer, and further includes other layers appropriately selected as necessary.
For example, as shown in FIG. 1, the recording medium 100 includes a high quality paper 11 as a base paper, a solvent blocking layer 12 as a first layer formed on the high quality paper 11, and a solvent blocking layer 12. And an ink absorption layer 13 as a formed second layer.
The recording medium may be either sheet paper or roll paper.

<Base paper>
There is no restriction | limiting in particular as said base paper, According to the objective, it can select suitably from well-known things.

  The pulp that can be used as the raw material of the base paper is preferably hardwood bleached kraft pulp (LBKP) from the viewpoint of improving the surface smoothness, rigidity and dimensional stability (curlability) of the base paper in a well-balanced and sufficient level. However, softwood bleached kraft pulp (NBKP), hardwood sulfite pulp (LBSP) and the like can also be used.

A beater or refiner can be used for beating the pulp. The pulp slurry obtained after beating the pulp (hereinafter sometimes referred to as “pulp stock”) includes various additives as necessary, for example, filler, dry paper strength enhancer, sizing agent, and wet. A paper strength enhancer, a fixing agent, a pH adjuster, an antioxidant and other chemicals are added.
Further, the base paper preferably has a Steecht sizing degree defined in JIS P8140 of 2 seconds or more.

  Examples of the filler include calcium carbonate, clay, kaolin, white clay, talc, titanium oxide, diatomaceous earth, barium sulfate, aluminum hydroxide, magnesium hydroxide and the like. Examples of the dry paper strength enhancer include cationized starch, cationized polyacrylamide, anionized polyacrylamide, amphoteric polyacrylamide, and carboxy-modified polyvinyl alcohol. Examples of the sizing agent include rosin derivatives such as fatty acid salts, rosin and maleated rosin, paraffin wax, alkyl ketene dimer, alkenyl succinic anhydride (ASA), and epoxidized fatty acid amide.

  Examples of the wet paper strength enhancer include polyamine polyamide epichlorohydrin, melamine resin, urea resin, and epoxidized polyamide resin. Examples of the fixing agent include polyvalent metal salts such as aluminum sulfate and aluminum chloride, and cationic polymers such as cationized starch. Examples of the pH adjuster include caustic soda and sodium carbonate.

  Examples of other chemicals include antifoaming agents, dyes, slime control agents, fluorescent whitening agents, and the like. Moreover, a softening agent etc. can also be added as needed. The softening agent is described in, for example, New Paper Processing Handbook (edited by Paper Medicine Time), pages 554 to 555 (issued in 1980).

  The treatment liquid used for the surface sizing treatment may contain, for example, a water-soluble polymer, a sizing agent, a water-resistant substance, a pigment, a pH adjusting agent, a dye, and a fluorescent brightening agent. Examples of the water-soluble polymer include cationized starch, polyvinyl alcohol, carboxy-modified polyvinyl alcohol, carboxymethyl cellulose, hydroxyethyl cellulose, cellulose sulfate, gelatin, casein, sodium polyacrylate, styrene-maleic anhydride copolymer sodium salt, Examples thereof include sodium polystyrene sulfonate.

  Examples of the sizing agent include petroleum resin emulsion, ammonium salt of styrene-maleic anhydride copolymer alkyl ester, rosin, higher fatty acid salt, alkyl ketene dimer (AKD), epoxidized fatty acid amide, alkylamine / epihalohydrin polycondensate. Etc.

  Examples of the water resistant substance include latex / emulsions such as styrene-butadiene copolymer, ethylene-vinyl acetate copolymer, polyethylene, vinylidene chloride copolymer, and polyamide polyamine epichlorohydrin.

  Examples of the pigment include calcium carbonate, clay, kaolin, talc, barium sulfate, and titanium oxide. Examples of the pH adjuster include hydrochloric acid, caustic soda, sodium carbonate, and the like.

  Examples of the antioxidant include known antioxidants that have been widely used as additives for conventional plastics. Known antioxidants include, for example, radical chain inhibitors such as phenolic and amine compounds, peroxide decomposers such as sulfur and phosphorus compounds, chain initiation inhibitors such as hydrazine and amides, and the like. It is done.

  Examples of the radical chain inhibitor include 2,6-di-t-butyl-p-cresol, 2,6-di-t-butyl-phenol, 2,4-di-methyl-6-t-butyl-phenol, Butylhydroxyanisole, 2,2′-methylenebis (4-methyl-6-tert-butylphenol), 4,4′-butylidenebis (3-methyl-6-tert-butylphenol), 4,4′-thiobis (3-methyl) -6-tert-butylphenol), tetrakis [methylene-3 (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane, 1,1,3-tris (2-methyl-4-hydroxy-5) -T-butylphenyl) butane, phenyl-β-naphthylamine, α-naphthylamine, N, N′-di-sec-butyl-p-phenylenediamine, phenothiazi , N, N′-diphenyl-p-phenylenediamine, and as the peroxide decomposing agent, triphenyl phosphite, trioctadecyl phosphite, tridecyl phosphite, trilauryl trithiophosphite, dilauryl thiodipropionate , Distearyl thiodipropionate, lauryl stearyl thiodipropionate, dimyristyl thiodipropionate, distearyl β, β′-thiodibutyrate, 2-mercaptobenzimidazole, dilauryl sulfide, the chain initiation inhibitor N-salicyloyl-N′-aldehyde hydrazine, N-salicyloyl-N′-acetylhydrazine, N, N′-diphenyl-oxamide, N, N′-di (2-hydroxyphenyl) oxamide and the like.

  It is particularly preferred that a peroxide decomposing agent such as a sulfur-based or phosphorus-based compound is used in combination with a radical chain inhibitor. Peroxide decomposer has the effect of cleaving peroxides into inactive compounds to inhibit peroxide decomposition reaction and cleave contribution to chain reaction. Also, radical chain inhibitor and peroxide decomposer Are considered to have a synergistic effect. Further, it is believed that the peroxide decomposer has the ability to regenerate oxidized hindered phenol (radical chain inhibitor).

  As a means of incorporating these antioxidants into the base paper, when the pulp fibers are disaggregated and made into a slurry by a paper machine, a coating in which the antioxidant is dissolved or dispersed with a size press device or the like provided in the middle There are a method of immersing or coating the solution, a method of applying a coating solution containing an antioxidant to the base paper using a normal coating device, etc., but the base paper is a solution or dispersion of the antioxidant. It is convenient and preferable to impregnate the liquid.

  The dispersion of the antioxidant is prepared by, for example, dissolving the antioxidant once in a low boiling point solvent such as chlorofluorocarbons or acetone, adding a surfactant to this, adding a predetermined amount of water, stirring, and emulsifying. Can do. At this time, for example, a water-soluble polymer such as polyvinyl alcohol or carboxymethyl cellulose can be added, or other additives can be added as desired.

The content of the antioxidant in the base paper is 0.1 to 10 g / ^{m 2,} preferably from 1 to 5 g / ^{m 2.} If the addition amount is 0.1 g / m ² or less, a sufficient effect for improving discoloration resistance cannot be obtained, and even if added over 10 g / m ² , the effect for improving discoloration resistance is not improved. Density, ink absorbability, etc.).

  Examples of the material of the base paper include synthetic pulp paper, mixed paper of natural pulp and synthetic pulp, and various types of combined paper, in addition to the above-described natural pulp paper. The base paper is 30 to 500 μm, desirably 50 to 300 μm, more desirably 70 to 200 μm.

<First layer>
The first layer contains a binder and has a Cobb water absorption of 5.0 g / m ² or less at a contact time of 15 seconds according to a water absorption test specified in JIS P8140 on the base paper provided with the first layer. As long as it is, it is not particularly limited and can be appropriately selected from known ones according to the purpose. For example, according to the water absorption test defined in JIS P8140 on the base paper provided with the first layer. Cobb water absorption at a contact time of 2 minutes was 2.0 g / m ² or less, and was determined using diethylene glycol based on the water absorption test defined in JIS P8140 on the base paper provided with the first layer. it Cobb value of the contact time of 2 minutes is 5.0 g / ^{m 2} or less, as a binder, a thermoplastic resin and polyvinyl alcohol (in particular, the degree of polymerization 1000 or more Of acetoacetyl-modified polyvinyl alcohol), further containing a layered inorganic compound, mass ratio X of polyvinyl alcohol mass X and water-swellable synthetic mica mass Y as the layered inorganic compound / Y is 1 or more and 30 or less, further includes a hardener, further includes a white pigment, further includes a crosslinking agent capable of crosslinking the water-soluble binder, further includes an organic solvent, and the like. preferable.

A base paper provided with a solvent blocking layer (first layer) has a paper strength of 5 g / m ² when the Cobb water absorption is 15 g / m ² or less according to the water absorption test specified in JIS P 8140. It is possible to prevent deformation due to lowering and swelling. Preferably, the Cobb water absorption at a contact time of 2 minutes according to the water absorption test specified in JIS P 8140 is 2.0 g / m ² or less, and diethylene glycol based on JIS P 8140. If the Cobb value with a contact time of 2 minutes using is 5.0 g / m ² or less, the paper strength can be reduced and deformation due to swelling can hardly occur.

As a specific means, a water-dispersible latex in which a hydrophobic polymer insoluble or hardly soluble in water is dispersed as fine particles in an aqueous phase dispersion medium as a main component, the solid content is 3 to 20 g / m ² per side. By coating, almost complete water resistance is obtained.

  Further, in order to give the resin surface hydrophilicity that does not repel water, by preparing a solvent blocking layer in which white pigment is blended in an amount of 5 to 50 parts by weight per 100 parts of the binder, Application by laminating two layers becomes easy, and a base paper provided with a first layer compatible with water resistance is obtained.

  A white pigment having an aspect ratio of 30 or more can be blended up to 200 parts by weight of the white pigment per 100 parts by weight of the above-mentioned binder. It becomes good.

<< Binder >>
The binder contained in the first layer is not particularly limited as long as it contains at least one of a thermoplastic resin and polyvinyl alcohol (water-soluble binder), but preferably contains a thermoplastic resin.

  There is no restriction | limiting in particular as a thermoplastic resin, It uses selecting suitably from well-known thermoplastic resins and its latex, such as polyolefin resin (For example, the homopolymer of α-olefins, such as polyethylene and a polypropylene, or a mixture thereof). Can do. Among these, latex is preferable, polyester urethane latex, acrylic latex, acrylic silicone latex, acrylic epoxy latex, acrylic styrene latex, acrylic urethane latex, styrene-butadiene latex, acrylonitrile-butadiene latex, and vinyl acetate. Preferred are latexes, and it is preferable to use at least one selected from these. Among these, it is particularly preferable to select and use at least one selected from polyester urethane latex and acrylic silicone latex.

Examples of the polyester urethane latex include Hydran AP series and Hydran ECOS series manufactured by Dainippon Ink & Chemicals, Inc.
As the acrylic latex, a commercially available product can be used. For example, the following water-dispersible latex can be used. That is, examples of acrylic resins include “Cebian A4635, 46583, 4601” manufactured by Daicel Chemical Industries, Ltd., “Nipol Lx811, 814, 821, 820, 857” manufactured by Nippon Zeon Co., Ltd. .
In particular, acrylic emulsions of acrylic silicone latex described in JP-A-10-264511, JP-A-2000-43409, JP-A-2000-343811, and JP-A-2002-120452 (commercially available products include, for example, Daicel Trade names “Aquabrid Series UM7760, UM7611, UM4901, MSi-045, ASi-753, ASi-903, ASi-89, ASi-91, ASi-86, 4635, MSi-04S, AU manufactured by Chemical Industry Co., Ltd. -124, AU-131, AEA-61, AEC-69, AEC-162 ") and the like can also be suitably used.
In addition, said thermoplastic resin can also use 2 or more types together not only individually by 1 type.

  The glass transition temperature (Tg) of the thermoplastic resin is preferably 5 to 70 ° C, and particularly preferably 15 to 50 ° C. By making the Tg particularly in the above range, there is no difficulty in handling such as causing problems such as burrs of the first layer forming liquid (for example, coating liquid), and the Tg is too high. If the calendar temperature is not set to a very high level, the desired gloss cannot be obtained, and adhesion to the metal roll surface is likely to occur. High flatness can be obtained.

  Moreover, as minimum film-forming temperature of a thermoplastic resin, 20-60 degreeC is preferable and 25-50 degreeC is more preferable. By making the minimum film forming temperature range where film formation is possible when trying to form a film within the above range, problems such as burrs of the liquid for forming the first layer (for example, coating liquid) may occur. Sufficiently small pores to pass through the ink solvent quickly without being difficult to handle and without causing significant penetration when the second layer is formed and reducing the surface of the layer. It can be comprised in the layer which has property. Although a layer only provided with a liquid (for example, a coating liquid) does not have good glossiness, a high glossiness layer having microporosity can be obtained by performing a soft calender treatment later.

  In the case where the composition is formed in layers, the content of the thermoplastic resin in the first layer is preferably 15 to 95% by mass, and preferably 30 to 90% by mass with respect to the solid content of the first layer. % Is more preferable. By making the content particularly within the above range, ink solvent permeability can be obtained without impairing glossiness and flatness after calendar treatment, and the occurrence of bleeding over time can be more effectively prevented. Can do.

<< acetoacetyl-modified polyvinyl alcohol >>
In general, acetoacetyl-modified polyvinyl alcohol can be produced by adding and reacting a liquid or gaseous diketene to a solution, dispersion or powder of a polyvinyl alcohol resin. The degree of acetylation of the acetoacetyl-modified polyvinyl alcohol can be appropriately selected according to the quality of the target heat-sensitive recording material, but is 0.1 mol% to 20 mol%, more preferably 0.5 mol% to 10 mol%.

  The polyvinyl alcohol resin is obtained by saponifying a polyvinyl alcohol obtained by saponifying a lower alcohol solution of polyvinyl acetate and a derivative thereof, and a copolymer of a monomer capable of copolymerizing with vinyl acetate and vinyl acetate. included. Here, as monomers that can be copolymerized with vinyl acetate, (anhydrous) maleic acid, fumaric acid, crotonic acid, itaconic acid, (meth) acrylic acid and other unsaturated carboxylic acids and esters thereof, ethylene, propylene, etc. Α-olefin, olefin sulfonic acid such as (meth) allyl sulfonic acid, ethylene sulfonic acid, sulfonic acid malate, (meth) allyl sulfonic acid soda, ethylene sulfonic acid soda, sulfonic acid soda (meth) acrylate, sulfonic acid soda ( Monoalkylmalates), olefinic sulfonic acid alkali salts such as sodium disulfonic acid alkylmalate, amide group-containing monomers such as N-methylolacrylamide, alkali acrylamide alkylsulfonic acid salts, and N-vinylpyrrolidone derivatives Can be mentioned.

As the binder, in addition to the above-mentioned acetyl-modified polyvinyl alcohol, if necessary, a compound that dissolves 5% by mass or more in water at 25 ° C. may be used in combination. As these binders, polyvinyl alcohol (including carboxy-modified, itaconic acid-modified, maleic acid-modified, silica-modified and modified polyvinyl alcohol such as amino group modified), methylcellulose, carboxymethylcellulose, starches (including modified starch), gelatin Arabic rubber, casein, styrene-maleic anhydride copolymer hydrolyzate, polyacrylamide, saponified vinyl acetate-polyacrylic acid copolymer, and the like. These binders are used not only for dispersion but also for the purpose of improving the film strength. For this purpose, styrene / butadiene copolymer, vinyl acetate copolymer, acrylonitrile / butadiene copolymer, acrylic acid are used. Synthetic polymer latex binders such as methyl-butadiene copolymer and polyvinylidene chloride can be used in combination. Moreover, according to the kind of these binders, you may add the crosslinking agent of a suitable binder as needed.
Moreover, the acetoacetyl modified polyvinyl alcohol contained in the first layer has large oxygen permeation suppression and high SS characteristics. Here, the SS characteristic means a tensile energy absorption amount (toughness) expressed by stress-elongation until the film breaks. Therefore, the first layer freely expands and contracts even in a process that requires heating, does not generate a crack, and does not easily generate blisters.

  In the present invention, the degree of polymerization of acetoacetyl-modified polyvinyl alcohol is preferably 1,000 or more, and more preferably 1,500 or more. When the degree of polymerization is 1,000 or more, the effect of suppressing the occurrence of cracks in a low-humidity environment (for example, 20 ° C., 10%) is increased. This is considered due to the fact that the strength and elongation at break can be remarkably increased by increasing the degree of polymerization to 1,000 or more. Further, when the degree of polymerization is increased, the viscosity of the coating liquid is improved and the surface state of the coating is lowered. However, the disadvantage can be compensated by reducing the concentration of the coating liquid and the ratio of the water-dispersible mica.

  The modification rate of the acetoacetyl-modified polyvinyl alcohol is preferably 0.05 to 20 mol% from the viewpoint of water resistance by reaction with a hardener and stability in an aqueous solution. More preferably, it is mol%.

  The saponification degree of the acetoacetyl-modified polyvinyl alcohol is not particularly limited, but is preferably 80 to 99.5%. If the degree of saponification decreases, the elongation at break increases. Further, when the degree of polymerization is high, the degree of saponification increases, but when the degree of polymerization is low, it is preferable to reduce the degree of saponification. Further, when the degree of saponification is lowered, the elongation can be increased, while there are advantages that the viscosity is lowered and the leveling of the coated surface is improved and the coated surface is improved.

<< Cobb water absorption >>
The Cobb water absorbency is obtained by a water absorbency test specified in JIS P8140, and measures the amount of water absorbed when water contacts from one side of paper for a certain period of time. The contact time was 15 seconds and 2 minutes.

<< Cobb value >>
The Cobb value is a value obtained by measuring the amount of diethylene glycol absorbed when diethylene glycol contacts from one side of the paper for a certain period of time based on a water absorption test method defined in JIS P8140, with a contact time of 2 minutes. The contact time was 2 minutes.

<< Layered inorganic compound >>
The first layer preferably further contains a layered inorganic compound. As the layered inorganic compound, a swellable inorganic layered compound is preferable, and examples of these compounds include swellable viscosity minerals such as bentonite, hectorite, saponite, beiderite, nontronite, stevensite, beidellite, montmorite, and swelling. Synthetic mica, swellable synthetic smectite, and the like. These swellable inorganic layered compounds have a laminated structure composed of unit crystal lattice layers having a thickness of 1 to 1.5 nm, and the substitution of metal atoms in the lattice is significantly larger than other clay minerals. As a result, the lattice layer is deficient in positive charge, and cations such as Na ⁺ , Ca ²⁺ and Mg ²⁺ are adsorbed between the layers in order to compensate for this. The cations present between these layers are called exchangeable cations and exchange with various cations. In particular, when the cation between layers is Li ⁺ , Na ⁺ or the like, since the ionic radius is small, the bond between the layered crystal lattices is weak, and the layer swells greatly with water. If shear is applied in this state, it will easily cleave and form a stable sol in water. Bentonite and swellable synthetic mica have a strong tendency and are preferable for the purpose of the present invention. In particular, water-swellable synthetic mica is preferable.

Examples of water-swellable synthetic mica include Na tetrathic mica NaMg _2.5 (Si ₄ O ₁₀ ) F ₂ Na, Li teniolite (NaLi) Mg ₂ (Si ₄ O ₁₀ ) F ₂ Na, or Li hectorite (NaLi). / 3Mg ₂ / 3Li _1/3 Si ₄ O ₁₀ ) F _{2 and the} like.

  The water-swellable synthetic mica preferably used in the present invention has a thickness of 1 to 50 nm and a surface size of 1 to 20 μm. For diffusion control, the thinner the better, the better the plane size, as long as the smoothness and transparency of the coated surface are not deteriorated. Accordingly, the aspect ratio is 100 or more, preferably 200 or more, particularly preferably 500 or more.

<< mass ratio >>
The mass ratio X / Y of the mass X of the acetoacetyl-modified polyvinyl alcohol and the mass Y of the water-swellable synthetic mica contained in the first layer is preferably in the range of 1 to 30, and preferably 5 to 15. The following range is more preferable. When the mass ratio is in the range of 1 or more and 30 or less, the effect is great in suppressing oxygen permeation and blistering.

<< Hardener >>
The hardening agent in the first layer of the present invention includes an aldehyde compound, 2,3-dihydroxy-1,4-dioxane and derivatives thereof, and a vinyl adjacent to a substituent having a positive Hammett substituent constant σp. It is at least one selected from compounds having two or more groups in a single molecule. The first layer in the present invention is adjacent to a aldehyde compound, 2,3-dihydroxy-1,4-dioxane and a derivative thereof, and a substituent having a positive Hammett's substituent constant σp as a hardener. By containing at least one selected from compounds having two or more vinyl groups in a single molecule, it reacts with acetoacetyl-modified polyvinyl alcohol without increasing the viscosity of the first layer coating solution Thus, the water resistance of the recording material can be improved, and as a result, a recording material in which the water resistance of the recording material and the coating stability of the first layer coating solution are improved can be obtained.

As substituents having a positive Hammett's substituent constant σp, CF ₃ group (σp value: 0.54), CN group (σp value: 0.66), COCH ₃ group (σp value: 0.50), COOH group (σp value: 0.45), COOR (R represents an alkyl group) group (σp value: 0.45), NO ₂ group (σp value: 0.78), OCOCH ₃ group (σp value: 0.31), SH group (σp value: 0.15), SOCH ₃ group (σp value: 0.49), SO ₂ CH ₃ group (σp value: 0.72), SO ₂ NH ₂ group (σp value) : 0.57), SCOCH ₃ group (σp value: 0.44), F group (σp value: 0.06), Cl group (σp value: 0.23), Br group (σp value: 0.23) , I group (σp value: 0.18), IO ₂ group (σp value: 0.76), N ⁺ (CH ₃ ) ₂ group (σp value: 0.82), S ⁺ (CH ₃ ) ₂ group ( σp value: 0. 0), and the like.

  The compound having two or more vinyl groups adjacent to a substituent having a positive Hammett substituent constant σp in a single molecule is 2-ethylenesulfonyl-N- [2- (2-ethylenesulfonyl-acetylamino). ) -Ethyl] acetamide, bis-2-vinylsulfonylethyl ether, bisacryloylimide, NN′-diaacryloylurea, 1,1-bisvinylsulfoneethane, ethylene-bis-acrylamide, and the following structural formula And 2-ethylenesulfonyl-N- [2- (2-ethylenesulfonyl-acetylamino) -ethyl] acetamide is particularly preferable among them.

  The content of the compound having two or more vinyl groups adjacent to the substituent having a positive Hammett's substituent constant σp in the first layer in the single molecule is 0. 1 mass% or more and 30 mass% or less are preferable, and 0.5 mass% or more and 10 mass% or less are more preferable. When the content of the compound in the first layer is 0.5% by mass or more and 10% by mass or less with respect to acetoacetyl-modified polyvinyl alcohol, the first layer coating liquid does not thicken. Further, the effect of the above-described compound in the present invention that the water resistance of the recording material can be improved can be further exhibited.

<< white pigment >>
Examples of the white pigment include titanium oxide, barium sulfate, barium carbonate, calcium carbonate, lithopone, alumina white, zinc oxide, silica, antimony trioxide, titanium phosphate, aluminum hydroxide, kaolin, clay, talc, magnesium oxide, And magnesium hydroxide. These can be used individually by 1 type or in mixture of 2 or more types. Of these, kaolin is particularly preferred.

<<<< Kaolin >>>>
The kaolin preferably has an aspect ratio (diameter / thickness) of 30 or more. Examples of kaolin having an aspect ratio of 30 or higher include engineered grades (for example, Contour 1500 (aspect ratio 59), Astra-Plate (aspect ratio 34)). Further, when the kaolin has a high whiteness and a steep particle size distribution (uniform particle size), it provides excellent whiteness and printing suitability for various coated papers.

  The particle size of the white pigment is preferably 75% or more of particles of 2 μm or less, and more preferably 0.1 to 0.5 μm in average particle size. By setting the particle size in the above range, it is possible to effectively avoid a decrease in whiteness or a decrease in gloss.

  The titanium oxide may be either a rutile type or an anatase type, and these may be used alone or in combination. Further, any of those manufactured by the sulfuric acid method and those manufactured by the chlorine method may be used. Examples of the titanium oxide include hydrous alumina treatment, hydrous silicon dioxide treatment, or surface coating treatment with an inorganic substance such as zinc oxide treatment, trimethylolmethane, trimethylolethane, trimethylolpropane, and 2,4-dihydroxy-2. -It can select suitably from what carried out surface coating processing by organic substances, such as methylpentane, or siloxane processing, such as polydimethylsiloxane.

  The refractive index of the white pigment is preferably 1.5 or more. When a white pigment having a refractive index in this range is included, a high-quality image can be formed.

Further, the specific surface area of the white pigment by the BET method is preferably less than 100 m ² / g, and when a white pigment having a specific surface area in this range is included, the coating liquid for coating and forming the second layer Infiltration can be suppressed and the ink absorbability of the second layer can be increased.
The BET method is one of the methods for measuring the surface area of a powder by a vapor 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 an adsorption isotherm. Usually, nitrogen gas is used as the adsorbed gas, and a method of measuring the amount of adsorption from the change in pressure or volume of the gas to be adsorbed is common. A prominent expression of the isotherm of multimolecular adsorption is the Brunauer Emmett and Teller equation (BET equation). Based on this, the amount of adsorption is obtained, and the surface area is obtained by multiplying the area occupied by one adsorbed molecule. .

In the case where the composition is formed in layers, the content of the white pigment in the first layer varies depending on the type of white pigment, the type of thermoplastic resin, the layer thickness, etc. Usually, about 50 parts by mass to 200 parts by mass is desirable with respect to parts.
In addition, well-known additives, such as antioxidant, can also be added to a 1st layer.

  As a film thickness at the time of forming a 1st layer using the said composition, the range of 1-30 micrometers is preferable, and the range of 5-20 micrometers is more preferable. By making the film thickness within the above range, the glossiness of the surface that has been calendered later and the whiteness with a small amount of white pigment can be obtained, and at the same time, the handleability such as the bendability is equivalent to that of coated paper and art paper. Can be. In addition, since the first layer contains a white pigment, there is an effect that sticking to the calendar can be prevented when the calendar treatment is performed after the first layer is applied.

<< Crosslinking agent capable of crosslinking water-soluble binder >>
A crosslinking agent (hardener) is used together with the water-soluble binder. Specific examples of the crosslinking agent include aldehyde compounds such as formaldehyde and glutaraldehyde, ketone compounds such as diacetyl and chloropentanedione, bis (2-chloroethylurea) -2-hydroxy-4,6-dichloro-1, 3,5 triazine, compound having reactive halogen as described in US Pat. No. 3,288,775, divinyl sulfone, compound having reactive olefin as described in US Pat. No. 3,635,718, US Patent N-methylol compounds as described in US Pat. No. 2,732,316, isocyanates as described in US Pat. No. 3,103,437, US Pat. Nos. 3,017,280 and 2,983,611 Aziridine compounds such as these, carbodiimide compounds as described in US Pat. No. 3,100,704, Epoxy compounds as described in No. 3,091,537, halogen carboxaldehydes such as mucochloric acid, dioxane derivatives such as dihydroxydioxane, chromium alum, zirconium sulfate, boric acid and inorganic cross-linking agents such as borate, etc. Can be used alone or in combination of two or more.

  The addition amount of the crosslinking agent is appropriately determined depending on the type of crosslinking agent, the type and addition amount of the water-soluble binder, and the type and addition amount of the inorganic fine particles. Usually, it is used in the range of 0.1 to 40% by weight with respect to the water-soluble binder.

The crosslinking agent is preferably added in-line to the second coating solution immediately before the second coating solution for forming the second layer is applied. The crosslinking agent added in-line may be a part of the total amount of the crosslinking agent or the total amount. From the viewpoint of improving cracks and cracks, an appropriate in-line additive ratio can be determined empirically. The flow rate is set according to the concentration of the solution for in-line addition of the cross-linking agent, and a predetermined amount of the cross-linking agent is added to a predetermined amount of coating liquid controlled by a flow meter.

<< Organic solvent >>
As the organic solvent, the solubility in pure water of 20 ° C. is not less than 1 wt%, and, SP value ^{8.9 (cal} / cm 3) at ^{0.5 ~13 (cal / cm 3)} 0.5 Preferably there is. If the solubility is lower than 1% by mass, repellency during coating or layer separation is likely to occur, so that the gloss of the ink receiving layer is lowered.

<Second layer>
The second layer contains a white pigment and is not particularly limited as long as the water absorption amount at a contact time of 0.5 seconds by the Bristow method is 2 mL / m ² or more and 8 mL / m ² or less. For example, it may further include a water-soluble binder, a cross-linking agent capable of cross-linking the water-soluble binder, a nonionic surfactant, and an organic solvent. In addition, the water absorption amount for a contact time of 0.9 seconds determined using pure water containing 30% by mass of diethylene glycol by the Bristow method is 1 mL / m ² or more and 6 mL / m ² or less, other binder (heat A plastic resin), a solid mass part of 10 to 60 parts of a plastic resin per 100 parts of a white pigment solid mass part, and a membrane surface pH is acidic. Etc. are preferred.

In the second layer, when the water absorption amount at a contact time of 0.5 seconds by the Bristow method exceeds 8 mL / m ² , the ink solvent is rapidly absorbed into the recording medium, and the agglomeration reaction of the ink near the surface hardly occurs. The image is transferred to a fixing roller, and the printed matter becomes dirty.

On the other hand, if the water absorption is less than 2 mL / m ² , the solvent is embraced during the ink agglomeration reaction, causing a problem of image deformation.

When the water absorption at a contact time of 0.9 seconds determined by using Bristow's method using pure water containing 30% by mass of diethylene glycol close to the actual ink solvent component exceeds 6 mL / m ² , the same printed matter stains as above. When the water absorption amount is less than 1 mL / m ² , the problem of image deformation occurs.

The second layer has a water absorption amount of 2 mL / m ² or more and 8 mL / m ² or less, with a contact time of 0.5 seconds determined by the Bristow method, preferably determined using pure water containing 30% by mass of diethylene glycol by the Bristow method. As a specific means for adjusting the water absorption amount for 0.9 second contact time to 1 mL / m ² or more and 6 mL / m ² or less, in the second layer, the blending range of the binder per 100 parts by mass of the white pigment is set. 5 to 15 parts by mass.

<<< White Pigment >>>
The white pigment is not particularly limited. For example, calcium carbonate, kaolin, titanium dioxide, aluminum trihydroxide, zinc oxide, barium sulfate, satin white, talc and the like are generally used as white pigments for coated paper for printing. You can choose from the inside. By including a white pigment in the second layer, there is an effect that the pigment in the ink composition can be retained in the second layer.

<< Bristow method >>
The Bristow method is the most popular method for measuring the amount of liquid absorbed in a short time, and is also adopted by the Japan Paper Pulp Technology Association (J'TAPPI). Details of the test method are described in J'TAPPI No. 51, “Method for testing liquid absorbency of paper and paperboard”. At the time of measurement, the head box slit width of the Bristow test is adjusted according to the surface tension of the ink. Also, the point where the ink is removed from the back of the paper is excluded from the calculation.

<< Water-soluble binder >>
The water-soluble binder is not particularly limited, but starch, modified starch such as cationized starch, polyvinyl alcohol, carboxy-modified polyvinyl alcohol, carboxymethyl cellulose, hydroxyethyl cellulose, cellulose sulfate, gelatin, casein, sodium polyacrylate, styrene- Maleic anhydride copolymer sodium salt, sodium polystyrene sulfonate and the like are preferably used. It is preferably at least one of polyvinyl alcohol and modified polyvinyl alcohol.

<<< Modified polyvinyl alcohol >>>
The modified polyvinyl alcohol is preferably acetoacetyl-modified polyvinyl alcohol or silanol-modified polyvinyl alcohol having a polymerization degree of 500 or more, preferably 1,000 or more. Here, the silanol-modified polyvinyl alcohol is one that can be produced by a conventionally known synthesis method described in, for example, Die Angelwandte Makromolekule Chemie 81, 137 (1979). Vinyl trimethoxysilane and vinyl acetate Can be copolymerized in methanol and the like, and then vinyl acetate is saponified by methanolysis using sodium hydroxide as a catalyst to obtain the desired polymer. The silanol-modified polyvinyl alcohol preferably has a saponification degree of 85% or more, a polymerization degree of about 500 to 2000, and the content of silanol groups in the molecule as a monomer unit of 0.05 to 3 mol%. As such silanol-modified polyvinyl alcohol, commercially available products can be suitably used, and examples thereof include R-1130, R-2105, R-2130 (manufactured by Kuraray Co., Ltd.) and the like.

<< Crosslinking agent capable of crosslinking water-soluble binder >>
A crosslinking agent (hardener) is used together with the water-soluble binder. Specific examples of the crosslinking agent include aldehyde compounds such as formaldehyde and glutaraldehyde, ketone compounds such as diacetyl and chloropentanedione, bis (2-chloroethylurea) -2-hydroxy-4,6-dichloro-1, 3,5 triazine, compound having reactive halogen as described in US Pat. No. 3,288,775, divinyl sulfone, compound having reactive olefin as described in US Pat. No. 3,635,718, US Patent N-methylol compounds as described in US Pat. No. 2,732,316, isocyanates as described in US Pat. No. 3,103,437, US Pat. Nos. 3,017,280 and 2,983,611 Aziridine compounds such as these, carbodiimide compounds as described in US Pat. No. 3,100,704, Epoxy compounds as described in No. 3,091,537, halogen carboxaldehydes such as mucochloric acid, dioxane derivatives such as dihydroxydioxane, chromium alum, zirconium sulfate, boric acid and inorganic cross-linking agents such as borate, etc. Can be used alone or in combination of two or more.

  The addition amount of the crosslinking agent is appropriately determined depending on the type of crosslinking agent, the type and addition amount of the water-soluble binder, and the type and addition amount of the inorganic fine particles. Usually, it is used in the range of 0.1 to 40% by weight with respect to the water-soluble binder.

The crosslinking agent is preferably added in-line to the second coating solution immediately before the second coating solution for forming the second layer is applied. The crosslinking agent added in-line may be a part of the total amount of the crosslinking agent or the total amount. From the viewpoint of improving cracks and cracks, an appropriate in-line additive ratio can be determined empirically. The flow rate is set according to the concentration of the solution for in-line addition of the cross-linking agent, and a predetermined amount of the cross-linking agent is added to a predetermined amount of coating liquid controlled by a flow meter.

<< Nonionic surfactant >>
Nonionic surfactants (including amphoteric surfactants) include nonionic surfactants such as alkyl glycosides, amino acid type, carboxyammonium betaine type, sulfoammonium betaine type, ammonium sulfate betaine type, and imidazo. Examples include amphoteric surfactants such as linium betaine type, such as U.S. Pat. No. 3,843,368, JP-A-59-49535, JP-A-63-236546, JP-A-5-303205, and JP-A-8. No. 262742 and Hei 10-282619. Amino acid type amphoteric surfactants are those derivatized from, for example, amino acids (glycine, glutamic acid, histidine acid, etc.) as described in JP-A-5-303205, and have long-chain acyl groups. N-aminoacyl acid and its salt introduced.
Further, a tertiary alcohol having an acetylene bond in the molecule, which is preferably used as a nonionic surfactant (an amphoteric surfactant), is generally referred to as acetylene alcohol. For example, 2, 4, 7 represented by Chemical Formula 1 , 9-tetramethyl-5-decyne-4,7-diol ethylene oxide adduct.

  The average added mole number (m + n) of ethylene oxide of acetylene alcohol is particularly preferably 3 or more and 5 or less. If the average added mole number of ethylene oxide exceeds 5, the solubility in water becomes high, and when the ink is absorbed, it is eluted by components in the ink, and bleeding may occur in the printed portion. is there. In addition, when the average added mole number is less than 3, the effect may not be sufficiently exhibited.

  Moreover, the preferable addition amount of this ethylene oxide adduct of acetylene alcohol is 0.01 to 1 weight% with respect to a coating liquid, Most preferably, it is 0.1 to 0.5 weight%. If the added amount is less than 0.01% by weight, the effect is not sufficiently exhibited. If the added amount exceeds 1% by weight, the coating liquid is likely to be repelled and a good coated surface is obtained. It may not be possible.

<< Organic solvent >>
As the organic solvent, the solubility in pure water of 20 ° C. is not less than 1 wt%, and, SP value ^{8.9 (cal} / cm 3) at ^{0.5 ~13 (cal / cm 3)} 0.5 Preferably there is. If the solubility is lower than 1% by mass, repellency during coating or layer separation is likely to occur, so that the gloss of the ink receiving layer is lowered.

<< Other binders (thermoplastic resin) >>
There is no restriction | limiting in particular as another binder (thermoplastic resin), For example, the thing similar to what was used by the 1st layer can be used.

<< Membrane surface pH >>
By adjusting the film surface pH of the second layer to be acidic, the ink can be aggregated and the fixing of the ink can be improved.
As the acidifying compound used in this embodiment, a phosphoric acid group, a phosphonic group, a phosphine group, a sulfuric acid group, a sulfonic acid group, a sulfinic acid, a carboxylic acid or a salt thereof can be used. More preferably, it is an acid group. Examples of phosphoric acid include phosphoric acid, polyphosphoric acid, derivatives of these compounds, or salts thereof. Examples of carboxylic acids include furan, pyrrole, pyrroline, pyrrolidone, pyrone, pyrrole, thiophene, indole, pyridine, and quinoline structures. A compound having a carboxyl group as a functional group, such as pyrrolidone carboxylic acid, pyrone carboxylic acid, pyrrole carboxylic acid, furan carboxylic acid, pyridine carboxylic acid, coumaric acid, thiophene carboxylic acid, nicotinic acid, or these A derivative of a compound or a salt thereof can be added to the coating solution for the second layer to adjust the film surface pH to be acidic.
The measurement of the membrane surface pH can be performed by the A method (coating method) of the measurement of the membrane surface PH determined by the Japan Pulp and Paper Technology Association (J.TAPPI). ) It can be carried out by using a PH measurement set for paper “model MPC” manufactured by Kyoritsu Riken.

<Other layers>
There is no restriction | limiting in particular as another layer, According to the objective, it can select suitably.

(Recording medium manufacturing method)
The method for producing a recording medium of the present invention includes a first coating step, a drying step, and a second coating step, and further includes other steps that are appropriately selected as necessary.

<First coating process>
There is no restriction | limiting in particular as said 1st coating process except apply | coating the 1st coating liquid which forms a 1st layer on a base paper, According to the objective, it can select suitably.

<Drying process>
The drying step is not particularly limited except that after the first coating step, the first applied coating solution is continuously introduced into the hot air dryer group and dried. It can be appropriately selected depending on the case. The first coating liquid dried in the drying step preferably has a solid content concentration of 98% or less, and more preferably a solid content concentration of 80% or less.

<< Solid content concentration >>
The solid content concentration can be measured by removing the dried first coating liquid from the base paper and using a drying method. For example, a laser type surface inspection meter (SU-12 coaxial laser beam manufactured by High Frequency Communication Industry Co., Ltd.) can be used. It is also possible to measure the reflectance of the coating film using a center and display it as a voltage, and to obtain the solid content concentration based on the displayed voltage (see JP-A-6-108395).

<Second coating process>
As a 2nd coating process, after applying a 2nd coating liquid which forms a 2nd layer on the dried 1st coating liquid continuously after a drying process. Although there is no restriction | limiting in particular, Although it can select suitably according to the objective, It is preferable to apply a 2nd coating liquid by curtain application | coating (for example, refer patent document 326883).

<Other processes>
There is no restriction | limiting in particular as another process, According to the objective, it can select suitably.

(Inkjet recording method)
The ink jet recording method of the present invention includes an ink drawing process and a drying and removing process, and further includes other processes appropriately selected as necessary.

<Ink drawing process>
There is no restriction | limiting in particular as said ink drawing process other than drawing ink according to predetermined | prescribed image data, According to the objective, it can select suitably.

<Dry removal process>
The drying and removing step is not particularly limited except that the ink solvent in the recording medium on which the ink has been drawn is removed by drying, and can be appropriately selected according to the purpose. In the recording medium of the present invention, since the ink absorbing layer as the second layer is slowly permeable, the drying removal step is performed in a state where the ink solvent (water) is present near the surface of the recording medium.

<Other processes>
Other steps are not particularly limited and may be appropriately selected depending on the purpose. Examples thereof include a treatment liquid supply step and a heat fixing step.

-Processing liquid supply process-
There is no restriction | limiting in particular as said process liquid supply process except supplying the process liquid containing the acidic substance mentioned later, According to the objective, it can select suitably.

-Heat fixing process-
The heat fixing step is not particularly limited except that the latex particles contained in the ink used in the ink jet recording method are melt-fixed, and can be appropriately selected depending on the purpose.

  In the ink jet recording method, an ink jet recording method 1 (FIG. 2) that performs ink drawing or the like on a recording medium in which the second layer (ink absorbing layer) contains an ink and an aggregating agent (treatment liquid) in advance. And an ink jet recording method 2 (FIG. 3) in which ink drawing or the like is performed after supplying the processing liquid to the recording medium (pre-coating).

-Inkjet recording method 1
In the inkjet recording method 1, for example, ink drawing, drying (water drying, blow drying), and fixing are performed under the following conditions.

--Ink drawing--
Head: 1,200 dpi / 20 inch width full line head Discharged droplet amount: 4-value recording of 0, 2.0, 3.5, 4.0 pL Driving frequency: 30 kHz (recording medium conveyance speed 635 mm / sec)

-Drying (water drying, blow drying)-
Wind speed: 8-15m / s
Temperature: 40-80 ° C
Air blowing area: 640 mm (drying time 1 second)

--Fixing--
Silicone rubber roller (hardness 50 °, nip width 5mm)
Roller temperature: 70-90 ° C
Pressure: 0.5-2.0 MPa

-Inkjet recording method 2-
In the inkjet recording method 2, for example, pre-coating, ink drawing, drying (water drying, air drying), and fixing are performed under the following conditions.

--- Treatment liquid head for precoat module-
Head: 600 dpi / 20 inch full line head Discharge droplet volume: 0, 4.0 pL binary recording Drive frequency: 15 kHz (recording medium conveyance speed 635 mm / sec)
Drawing pattern: In the ink drawing process, a pattern that applies treatment liquid in advance to the position where at least one color ink is drawn is applied.

--- Water drying for precoat module (blow drying)-
Wind speed 8-15m / s, temperature 40-80 ° C, blowing area 450mm (drying time 0.7 seconds)

--Ink drawing--
Head: 1200 dpi / 20 inch width full line head Discharged droplet amount: 4-value recording of 0, 2.0, 3.5, 4.0 pL Driving frequency: 30 kHz (recording medium conveyance speed 635 mm / sec)

-Drying (water drying, blow drying)-
Wind speed: 8-15m / s
Temperature: 40-80 ° C
Air blowing area: 640 mm (drying time 1 second)

--Fixing--
Silicone rubber roller (hardness 50 °, nip width 5mm)
Roller temperature: 70-90 ° C
Pressure: 0.5-2.0 MPa

<Water-based two-liquid aggregation ink>
In the ink jet recording method, an aqueous two-liquid aggregation ink comprising a treatment liquid and an ink that reacts and aggregates with the treatment liquid may be used.

-Treatment liquid-
As an acidic substance that makes the treatment solution acidic, a phosphoric acid group, a phosphonic acid group, a phosphinic acid group, a sulfuric acid group, a sulfonic acid group, a sulfinic acid, a carboxylic acid or a salt thereof can be used. It is more preferably an acid group, and even more preferably a carboxylic acid group. Examples of the carboxylic acid include furan, pyrrole, pyrroline, pyrrolidone, pyrone, pyrrole, thiophene, indole, pyridine, a compound having a quinoline structure and a carboxyl group as a functional group, such as pyrrolidone carboxylic acid, pyrone carboxylic acid, Pyrrole carboxylic acid, furan carboxylic acid, pyridine carboxylic acid, coumaric acid, thiophene carboxylic acid, nicotinic acid, derivatives of these compounds, or salts thereof are added to the treatment liquid.

  Moreover, as said acidic substance, it is preferable that they are pyrrolidone carboxylic acid, pyrone carboxylic acid, furan carboxylic acid, coumaric acid, or these compound derivatives, or these salts. In addition, these compounds may be used by 1 type and may be used together 2 or more types.

  Further, the treatment liquid may contain other additives within a range that does not impair the effects of the present invention. Other additives include, for example, anti-drying agents (wetting agents), anti-fading agents, emulsion stabilizers, penetration enhancers, ultraviolet absorbers, preservatives, anti-fungal agents, pH adjusters, surface tension adjusters, Well-known additives, such as a foaming agent, a viscosity modifier, a dispersing agent, a dispersion stabilizer, a rust preventive agent, a chelating agent, are mentioned.

-Ink-
The ink can be used not only for forming a single color image but also for forming a full color image. In order to form a full color image, a magenta color ink, a cyan color ink, and a yellow color ink can be used, and a black color ink may be further used to adjust the color tone. Further, red, green, blue, and white inks other than yellow, magenta, and cyan color inks, and so-called special color inks (for example, colorless) in the printing field can be used. Examples of the ink include those containing latex particles, an organic pigment, a dispersant, and a water-soluble organic solvent, and further containing other additives as necessary.

--Latex particles--
Examples of the latex particles include a polymer of a compound composed of a nonionic monomer, an anionic monomer, and a cationic monomer.

  The nonionic monomer means a monomer compound having no dissociative functional group, and the monomer compound in a broad sense means a compound alone or a compound that polymerizes with another compound. The monomer compound is preferably a monomer compound having an unsaturated double bond.

  An anionic monomer represents a monomer compound containing an anionic group that can have a negative charge, and the anionic group may be any one as long as it has a negative charge. A phosphonic acid group, a phosphinic acid group, a sulfuric acid group, a sulfonic acid group, a sulfinic acid group or a carboxylic acid group, more preferably a phosphoric acid group or a carboxylic acid group, and a carboxylic acid group. Further preferred.

  The cationic monomer represents a monomer containing a cationic group that can have a positive charge, and any cationic group may be used as long as it has a positive charge. A substituent is preferable, and a cationic group of nitrogen or phosphorus is more preferable. Further, it is more preferably a pyridinium cation or an ammonium cation.

--Organic pigments--
Examples of organic pigments for orange or yellow include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 128, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 180, C.I. I. And CI Pigment Yellow 185.

  Examples of organic pigments for magenta or red include C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. Pigment red 222, C.I. I. Pigment violet 19 and the like.

  Examples of organic pigments for green or cyan include C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 4, C.I. I. Pigment blue 16, C.I. I. Pigment blue 60, C.I. I. Pigment Green 7 and siloxane-crosslinked aluminum phthalocyanine described in US Pat. No. 4,311,775.

  Examples of organic pigments for black include C.I. I. Pigment black 1, C.I. I. Pigment black 6, C.I. I. Pigment black 7 and the like.

  Further, the average particle diameter of the organic pigment is preferably as small as possible from the viewpoint of transparency and color reproducibility, but is preferably large from the viewpoint of light resistance. As an average particle diameter which balances these, 10-200 nm is preferable, 10-150 nm is more preferable, 10-100 nm is further more preferable. In addition, the particle size distribution of the organic pigment is not particularly limited, and may be either a wide particle size distribution or a monodispersed particle size distribution. Two or more kinds of organic pigments having a monodispersed particle size distribution may be mixed and used.

  The addition amount of the organic pigment is preferably 1 to 25% by mass, more preferably 2 to 20% by mass, further preferably 5 to 20% by mass, and particularly 5 to 15% by mass with respect to the ink. preferable.

-Dispersant-
The organic pigment dispersant may be a polymer dispersant or a low molecular surfactant type dispersant. The polymer dispersant may be either a water-soluble dispersant or a water-insoluble dispersant.

  The low molecular surfactant type dispersant is added for the purpose of stably dispersing the organic pigment in an aqueous solvent while keeping the ink at a low viscosity. The low molecular dispersant is a low molecular dispersant having a molecular weight of 2,000 or less. The molecular weight of the low molecular dispersant is preferably 100 to 2,000, more preferably 200 to 2,000.

  The low molecular weight dispersant has a structure including a hydrophilic group and a hydrophobic group. In addition, the hydrophilic group and the hydrophobic group may be independently contained in one molecule or more, and may have a plurality of types of hydrophilic groups and hydrophobic groups. In addition, a linking group for linking a hydrophilic group and a hydrophobic group can be appropriately included.

  The hydrophilic group is anionic, cationic, nonionic, or a betaine type combining these.

  The anionic group may be any as long as it has a negative charge, but is preferably a phosphate group, phosphonic acid group, phosphinic acid group, sulfuric acid group, sulfonic acid group, sulfinic acid group or carboxylic acid group. More preferably a phosphoric acid group or a carboxylic acid group, and even more preferably a carboxylic acid group.

  The cationic group may be any as long as it has a positive charge, but is preferably an organic cationic substituent, and more preferably a nitrogen or phosphorus cationic group. Further, it is more preferably a pyridinium cation or an ammonium cation.

  Examples of the nonionic group include polyethylene oxide, polyglycerin, a part of sugar unit, and the like.

  The hydrophilic group is preferably an anionic group. The anionic group is preferably a phosphoric acid group, a phosphonic acid group, a phosphinic acid group, a sulfuric acid group, a sulfonic acid group, a sulfinic acid group or a carboxylic acid group, more preferably a phosphoric acid group or a carboxylic acid group. More preferably, it is a carboxylic acid group.

Moreover, when a low molecular dispersing agent has an anionic hydrophilic group, it is preferable that pKa is 3 or more from a viewpoint of making it contact with an acidic process liquid and promoting an aggregation reaction. The pKa of the low molecular dispersant in the present invention is a low molecular dispersant 1 in a tetrahydrofuran-water (3: 2 = V / V) solution.
It is a value obtained by titrating a dissolved mol / L solution with an acid or alkaline solution and experimentally obtained from a titration curve. If the pKa of the low molecular dispersant is 3 or more, theoretically, 50% or more of the anionic groups are in a non-dissociated state when in contact with a treatment solution having a pH of about 3. Accordingly, the water solubility of the low molecular weight dispersant is remarkably lowered, and an agglomeration reaction occurs. That is, the aggregation reactivity is improved. Also from this viewpoint, the low molecular dispersant preferably has a carboxylic acid group as an anionic group.

The hydrophobic group has a hydrocarbon-based structure, a fluorocarbon-based structure, a silicone-based structure, or the like, and is particularly preferably a hydrocarbon-based structure. Further, these hydrophobic groups may have a linear structure or a branched structure. The hydrophobic group may have a single chain structure or a chain structure of more than this, and may have a plurality of types of hydrophobic groups in the case of a structure of two or more chains.

  The hydrophobic group is preferably a hydrocarbon group having 2 to 24 carbon atoms, more preferably a hydrocarbon group having 4 to 24 carbon atoms, and further preferably a hydrocarbon group having 6 to 20 carbon atoms.

  Among the polymer dispersants, as the water-soluble dispersant, a hydrophilic polymer compound can be used.For example, natural hydrophilic polymer compounds include gum arabic, tragan gum, guar gum, karaya gum, locust bean gum, arabinogalactone, Plant polymers such as pectin and quince seed starch, seaweed polymers such as alginic acid, carrageenan and agar, animal polymers such as gelatin, casein, albumin and collagen, and microbial polymers such as xanthene gum and dextran Can be mentioned.

  For hydrophilic polymer compounds modified from natural products, fiber polymers such as methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, carboxymethylcellulose, starch-based polymers such as sodium starch glycolate and sodium starch phosphate Examples include molecules, seaweed polymers such as sodium alginate and propylene glycol alginate.

  Examples of the synthetic water-soluble polymer compound include vinyl polymers such as polyvinyl alcohol, polyvinyl pyrrolidone, and polyvinyl methyl ether, non-crosslinked polyacrylamide, polyacrylic acid or alkali metal salts thereof, water-soluble styrene acrylic resins, and the like. Acrylic resin, water-soluble styrene maleic acid resin, water-soluble vinyl naphthalene acrylic resin, water-soluble vinyl naphthalene maleic resin, polyvinyl pyrrolidone, polyvinyl alcohol, alkali metal salts of β-naphthalene sulfonic acid formalin condensate, quaternary ammonium and amino And a polymer compound having a salt of a cationic functional group such as a group in the side chain, a natural polymer compound such as shellac, and the like.

  Among these, those having a carboxyl group introduced from a homopolymer of acrylic acid, methacrylic acid or styrene acrylic acid or a copolymer of a monomer having another hydrophilic group are particularly preferred as the polymer dispersant.

  As the water-insoluble dispersant among the polymer dispersants, a polymer having both a hydrophobic part and a hydrophilic part can be used. For example, styrene- (meth) acrylic acid copolymer, styrene- (meth) acrylic Acid- (meth) acrylic acid ester copolymer, (meth) acrylic acid ester- (meth) acrylic acid copolymer, polyethylene glycol (meth) acrylate- (meth) acrylic acid copolymer, vinyl acetate-maleic acid copolymer Examples thereof include a polymer and a styrene-maleic acid copolymer.

  The weight average molecular weight of the dispersant is preferably from 3,000 to 100,000, more preferably from 5,000 to 50,000, still more preferably from 5,000 to 40,000, particularly preferably from 10,000 to 40,000. is there.

  The mixing mass ratio of the organic pigment and the dispersant is preferably in the range of 1: 0.06 to 1: 3, more preferably in the range of 1: 0.125 to 1: 2, and still more preferably 1: 0.125. 1: 1.5.

-Water-soluble organic solvent-
The water-soluble organic solvent is used for the purpose of preventing drying and promoting wetting. Further, the drying inhibitor is suitably used at the ink ejection port of the nozzle in the ink jet recording method, and prevents clogging due to drying of the ink for ink jet.

  The drying inhibitor is preferably a water-soluble organic solvent having a vapor pressure lower than that of water. Specific examples of the drying inhibitor include ethylene glycol, propylene glycol, diethylene glycol, polyethylene glycol, thiodiglycol, dithiodiglycol, 2-methyl-1,3-propanediol, 1,2,6-hexanetriol, Polyhydric alcohols represented by acetylene glycol derivatives, glycerin, trimethylolpropane, etc., polyvalent alcohols such as ethylene glycol monomethyl (or ethyl) ether, diethylene glycol monomethyl (or ethyl) ether, triethylene glycol monoethyl (or butyl) ether Lower alkyl ethers of alcohols, 2-pyrrolidone, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, heterocyclic rings such as N-ethylmorpholine, sulfolane, dimethyls Sulfoxide, sulfur-containing compounds such as 3-sulfolene, diacetone alcohol, polyfunctional compounds such as diethanolamine, and urea derivatives. Of these, the drying inhibitor is preferably a polyhydric alcohol such as glycerin or diethylene glycol. Moreover, said drying inhibitor may be used independently or may be used together 2 or more types. These drying inhibitors are preferably contained in the ink in an amount of 10 to 50% by mass.

  Further, the penetration accelerator is preferably used for the purpose of allowing the ink to penetrate better into the recording medium (printing paper). Specific examples of penetration enhancers include alcohols such as ethanol, isopropanol, butanol, di (tri) ethylene glycol monobutyl ether, 1,2-hexanediol, sodium lauryl sulfate, sodium oleate, and nonionic surfactants. Etc. can be used suitably. These penetration enhancers exhibit a sufficient effect when contained in the ink composition in an amount of 5 to 30% by mass. Further, it is preferable that the penetration enhancer is used within a range of an addition amount that does not cause printing bleeding and paper loss (print through).

  In addition to the above, the water-soluble organic solvent is also used for adjusting the viscosity. Specific examples of water-soluble organic solvents that can be used to adjust the viscosity include alcohols (eg, methanol, ethanol, propanol, isopropanol, butanol, isobutanol, sec-butanol, t-butanol, pentanol, hexanol, Cyclohexanol, benzyl alcohol), polyhydric alcohols (for example, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, hexanediol, pentanediol, glycerin, hexanetriol, Thiodiglycol), glycol derivatives (eg, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether) Ter, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, triethylene glycol monomethyl ether, ethylene glycol diacetate, ethylene glycol monomethyl ether acetate, Triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, ethylene glycol monophenyl ether), amine (eg, ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, morpholine, N-ethylmorpholine, Tylenediamine, diethylenetriamine, triethylenetetramine, polyethyleneimine, tetramethylpropylenediamine) and other polar solvents (eg, formamide, N, N-dimethylformamide, N, N-dimethylacetamide, dimethylsulfoxide, sulfolane, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, 2-oxazolidone, 1,3-dimethyl-2-imidazolidinone, acetonitrile, acetone). In addition, a water-soluble organic solvent may be used independently and may use 2 or more types together.

-Other additives-
Examples of the other additives include a drying inhibitor (wetting agent), an antifading agent, an emulsion stabilizer, a penetration accelerator, an ultraviolet absorber, an antiseptic, an antifungal agent, a pH adjuster, a surface tension adjuster, Well-known additives, such as an antifoamer, a viscosity modifier, a dispersing agent, a dispersion stabilizer, an antirust agent, a chelating agent, are mentioned. In the case of water-soluble ink, these various additives are added directly to the ink. When an oil-soluble dye is used in the form of a dispersion, it is generally added to the dispersion after the preparation of the dye dispersion, but it may be added to the oil phase or the aqueous phase at the time of preparation.

  The ultraviolet absorber is used for the purpose of improving image storability. Examples of ultraviolet absorbers include benzotriazoles described in JP-A Nos. 58-185677, 61-190537, JP-A-2-782, JP-A-5-97075, JP-A-9-34057, and the like. Compounds, benzophenone compounds described in JP-A No. 46-2784, JP-A No. 5-194433, US Pat. No. 3,214,463, etc., JP-B Nos. 48-30492, 56-211141, Cinnamic acid compounds described in, for example, Kaihei 10-88106, JP-A-4-298503, 8-53427, 8-239368, 10-182621, JP-A-8- No. 501291, etc., triazine compounds, Research Disclosure No. Compounds described in No. 24239, compounds that emit fluorescence by absorbing ultraviolet rays typified by stilbene-based and benzoxazole-based compounds, so-called fluorescent brighteners, can also be used.

The anti-fading agent is used for the purpose of improving image storage stability. As the antifading agent, various organic and metal complex antifading agents can be used. Organic anti-fading agents include hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indanes, chromans, alkoxyanilines, heterocycles, etc. Complex, zinc complex and the like. More specifically, Research Disclosure No. No. 17643, Nos. VII to I, J; 151
62, no. No. 18716, page 650, left column, ibid. No. 36544, page 527, ibid. No. 307105, page 872, ibid. The compounds described in the patent cited in US Pat. No. 15,162, and the compounds included in the general formulas and compound examples of representative compounds described in JP-A-62-215272, pages 127 to 137 can be used.

  Examples of the antifungal agent include sodium dehydroacetate, sodium benzoate, sodium pyridinethione-1-oxide, p-hydroxybenzoic acid ethyl ester, 1,2-benzisothiazolin-3-one and salts thereof. These are preferably used in an amount of 0.02 to 1.00% by weight in the ink.

  As the pH adjuster, a neutralizer (organic base, inorganic alkali) can be used. For the purpose of improving the storage stability of the inkjet ink, the pH adjuster is preferably added so that the inkjet ink has a pH of 6 to 10, and more preferably added to have a pH of 7 to 10.

  Examples of the surface tension adjusting agent include nonionic surfactants, cationic surfactants, anionic surfactants, betaine surfactants, and the like.

  In addition, the addition amount of the surface tension adjusting agent is preferably an addition amount that adjusts the surface tension of the ink to 20 to 60 mN / m, and preferably an addition amount that is adjusted to 20 to 45 mN / m, in order to eject droplets well by inkjet. More preferable is an addition amount adjusted to 25 to 40 mN / m.

  Specific examples of surfactants include fatty acid salts, alkyl sulfate esters, alkylbenzene sulfonates, alkyl naphthalene sulfonates, dialkyl sulfosuccinates, alkyl phosphate esters, naphthalene sulfonate formalin condensation in hydrocarbons. Products, anionic surfactants such as polyoxyethylene alkyl sulfates, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxy Nonionic surfactants such as ethylene alkylamine, glycerin fatty acid ester and oxyethyleneoxypropylene block copolymer are preferred. Further, SURFYNOLS (Air Products & Chemicals), which is an acetylene-based polyoxyethylene oxide surfactant, is also preferably used. An amine oxide type amphoteric surfactant such as N, N-dimethyl-N-alkylamine oxide is also preferred.

  Further, pages (37) to (38) of JP-A-59-157636, Research Disclosure No. The surfactants described in 308119 (1989) can also be used.

  Also, fluorine (fluorinated alkyl) surfactants, silicone surfactants, and the like described in JP-A Nos. 2003-322926, 2004-325707, and 2004-309806 are disclosed. By using, the abrasion resistance can be improved.

  These surface tension modifiers can also be used as antifoaming agents, and fluorine compounds, silicone compounds, chelating agents represented by EDTA, and the like can also be used.

Examples of the present invention will be described below, but the present invention is not limited to the following examples.
In the examples, “parts” and “%” are based on mass unless otherwise specified, and “polymerization degree” represents “average polymerization degree”.

(Example 1)
<Preparation of first layer (undercoat layer) coating solution (first coating solution)>
100 parts of titanium dioxide (trade name: Taipei R-780, manufactured by Ishihara Sangyo Co., Ltd.), Na salt of 25% special polycarboxylic acid type polymer (trade name: Demol EP, manufactured by Kao Corporation) 1.2 parts And 121.7 parts of water were mixed and dispersed using a non-bubbling kneader (trade name: NBK-2, manufactured by Nippon Seiki Seisakusho Co., Ltd.) to obtain a 45% titanium dioxide dispersion. Subsequently, 100 parts of water was obtained in 100 parts of 35% acrylic silicone latex aqueous dispersion (glass transition temperature 25 ° C., minimum film-forming temperature 20 ° C .; trade name: Aquabrid ASi-91, manufactured by Daicel Chemical Industries). After adding 3.9 parts of 45% titanium dioxide dispersion and stirring and mixing sufficiently, the liquid temperature of the obtained mixture was kept at 15 to 25 ° C. 1 coating solution) was obtained.

<Preparation of second layer (overcoat layer) coating solution (second coating solution)>
Kaolin (trade name: Kaoblite 90, manufactured by Shiraishi Calcium Co., Ltd.) 100 parts, 0.1N sodium hydroxide (manufactured by Wako Pure Chemical Industries, Ltd.) 3.8 parts, 40% sodium polyacrylate (trade name: Aron T-50, manufactured by Toagosei Co., Ltd. (1.3 parts) and water (49.6 parts) were mixed and dispersed using a non-bubbling kneader (trade name: NBK-2, manufactured by Nippon Seiki Seisakusho Co., Ltd.) 11.2 parts of a 50% styrene-butadiene copolymer latex (trade name: Nipol LX407K, manufactured by Nippon Zeon Co., Ltd.) having 65% kaolin dispersion and an average particle diameter of 130 nm, polyvinyl alcohol as a hydrophilic binder (trade name) : 28 parts of 5% aqueous solution of PVA245, manufactured by Kuraray Co., Ltd., saponification degree 88%, average polymerization degree 3,500), fatty acid calcium emulsion (trade name: Nopcoat C) 104-HS (manufactured by San Nopco) 1 part, 1% carboxymethylcellulose sodium salt (trade name: Serogen EP, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and 10% Emulgen 109P (manufactured by Kao Corporation) aqueous solution 0 .5 parts was added to prepare an overcoat layer coating solution having a final solid content concentration of 55%.

<Formation of first layer (undercoat layer)>
Using a high-speed sheet-fed coater (device name: PM-9040M, manufactured by SMT) on high-quality paper (trade name: Shiraoi, manufactured by Nippon Paper Industries) with a basis weight of 81.4 g / m ² for the undercoat layer obtained The coating liquid (first coating liquid) was applied with a wire rod coater head so that the coating amount was 10.0 g / m ² . Furthermore, the hot air dryer process shown below was performed with respect to the applied coating liquid for undercoat layers (1st coating liquid) with the drying mechanism of the apparatus.

<Drying by hot air dryer treatment>
Residual until the dry level of the coating solution for the undercoat layer (first coating solution) reaches 78% with a hot air dryer at a temperature of 100 ° C. and a wind speed of 20 m / sec, on the high-quality paper having the undercoat layer formed on the surface. It was done by letting.

<Formation of second layer (overcoat layer)>
Subsequently, after the drying, the prepared overcoat layer coating solution is applied to the surface on which the undercoat layer coating solution (first coating solution) has been applied, using the blade coater head of the apparatus. It apply | coated continuously, adjusting so that a quantity might be 20.0 g / m < ² >. Further, a hot-air dryer treatment was performed by the drying mechanism of the same apparatus until the film was completely dried, thereby forming an overcoat layer.

<Evaluation of recording medium>
About the recording medium obtained in Example 1, “Cobb water absorption test of high-quality paper on which an undercoat layer is formed”, “Water absorption test of topcoat layer”, “Adhesion test between topcoat layer and undercoat layer”, “ “Cuckling evaluation after printing” was performed as follows. The results are shown in Table 1.
A measurement sample of “Cobb water absorption test of fine paper on which an undercoat layer was formed” was prepared in the same manner as in Example 1 except that no overcoat layer was applied.

-Cobb water absorption test of fine paper with undercoat layer-
In accordance with the water absorption test specified in JIS P8140, the Cobb water absorption on the coated surface of the fine paper on which the undercoat layer is formed (water penetration amount g / m ² when contacted with water at 20 ° C. for 15 seconds) Was measured.

-Water absorption test of topcoat layer-
Based on the Bristow method, measurements were made as follows.
A sample cut to A6 size was placed on the measuring board with the top layer side up, and after touching the head filled with the test solution, the scanning line (from inside to outside) as shown in FIG. 4 was automatically scanned. The liquid absorption characteristics were measured. The measurement board changes the rotation speed (contact time between paper and ink) stepwise and rotates to obtain the relationship between the contact time and the liquid absorption amount (water absorption amount). Table 1 shows the water absorption amount at a contact time of 0.5 seconds.

-Adhesion test between topcoat layer and undercoat layer-
A sample cut into A6 size was coated with a mending tape manufactured by Sumitomo 3M Co., Ltd. on the surface of the topcoat layer side, peeled off after 1 minute, and the transfer amount of the topcoat layer transferred to the tape side was judged visually.
[Evaluation criteria]
A: Almost no peeling.
B: Although it peels off partly, there is no problem in quality.
C: Most part peels.

-Evaluation of cockle immediately after printing-
A 2cm x 2cm single-color 100% solid image is printed on a postcard size sample in the center of the postcard with an ink-jet printer PX-G930 (manufactured by Seiko Epson Corporation), and the maximum height of the corrugation generated immediately after printing is laser-displaced. Measured with a meter.

[Evaluation criteria]
A: 1 mm or more and less than 2 mm.
B: 2 mm or more and less than 3 mm.
C: 3 mm or more.

(Example 2)
In “Preparation of second layer (topcoat layer) coating solution (second coating solution)” in Example 1, the coating method for the topcoat layer coating solution is the curtain coating described in Japanese Patent No. 3901886. Further, a recording medium was produced in the same manner as in Example 1 except that boric acid was added to the coating solution for the topcoat layer immediately before the curtain coating (see Japanese Patent No. 3901886). The drying level of the undercoat layer coating liquid (first coating liquid) dried by the hot air dryer treatment was 78%. In addition, as in Example 1, “Cobb water absorption test of fine paper with an undercoat layer”, “Water absorption test of topcoat layer”, “Adhesion test between topcoat layer and undercoat layer”, “After printing” "Cuckle evaluation" was performed. The results are shown in Table 1.

(Example 3)
"Nonionic surfactant (trade name: Emulgen 109P, manufactured by Kao Corporation)" added in "Preparation of coating liquid (second coating liquid) for second layer (overcoat layer)" in Example 1 The recording medium was produced in the same manner as in Example 1, except that “nonionic surfactant (trade name: Olphine E1010 (acetylene type), manufactured by Nissin Chemical Co., Ltd.)” was changed. The drying level of the undercoat layer coating liquid (first coating liquid) dried by the hot air dryer treatment was 78%. In addition, as in Example 1, “Cobb water absorption test of fine paper with an undercoat layer”, “Water absorption test of topcoat layer”, “Adhesion test between topcoat layer and undercoat layer”, “After printing” "Cuckle evaluation" was performed. The results are shown in Table 1.

Example 4
In "Preparation of second layer (top coat layer) coating solution (second coating liquid)" in Example 1, butyl acetate as an organic solvent (SP value ^{8.70 (cal / cm 3) 0} . ^A recording medium was produced in the same manner as in Example 1 except that ⁵ ) was further added. The drying level of the undercoat layer coating liquid (first coating liquid) dried by the hot air dryer treatment was 78%. In addition, as in Example 1, “Cobb water absorption test of fine paper with an undercoat layer”, “Water absorption test of topcoat layer”, “Adhesion test between topcoat layer and undercoat layer”, “After printing” "Cuckle evaluation" was performed. The results are shown in Table 1.

(Example 5)
In “Preparation of coating liquid for second layer (overcoat layer) (second coating liquid)” in Example 1, diethylene glycol (DEG) (SP value is 12.1 (cal / cm ³ ) as an organic solvent. ^A recording medium was produced in the same manner as in Example 1 except that ^0.5 ) was further added and the drying level was 95%. The drying level of the undercoat layer coating liquid (first coating liquid) dried by the hot air dryer treatment was 95%. In addition, as in Example 1, “Cobb water absorption test of fine paper on which an undercoat layer was formed”, “Water absorption test of an overcoat layer”, “Adhesion test between an overcoat layer and an undercoat layer”, “After printing” "Cuckle evaluation" was performed. The results are shown in Table 1.

(Example 6)
In “Formation of the first layer (undercoat layer)” in Example 1, “quality paper (trade name: Shiraoi, manufactured by Nippon Paper Industries Co., Ltd.)” is “Stichtite sizing degree defined in JIS P8140 is 35 seconds. A recording medium was produced in the same manner as in Example 1 except that the base paper (Example 1 in JP-A-2003-182210) was changed. The drying level of the undercoat layer coating liquid (first coating liquid) dried by the hot air dryer treatment was 78%. In addition, as in Example 1, “Cobb water absorption test of fine paper on which an undercoat layer was formed”, “Water absorption test of an overcoat layer”, “Adhesion test between an overcoat layer and an undercoat layer”, “After printing” "Cuckle evaluation" was performed. The results are shown in Table 1.

(Example 7)
In “Formation of first layer (undercoat layer)” in Example 6, “Base paper having a sizing human sizing degree defined in JIS P8140 of 35 seconds (Example 1 in JP-A No. 2003-182210)” The recording medium was the same as in Example 6 except that the paper was changed to “base paper in which an alkylamine / epihalohydrin polycondensate was added as a sizing agent to a base paper having a sizing degree stipulated in JIS P8140 of 35 seconds” Was made. The drying level of the undercoat layer coating liquid (first coating liquid) dried by the hot air dryer treatment was 78%. In addition, as in Example 1, “Cobb water absorption test of fine paper with an undercoat layer”, “Water absorption test of topcoat layer”, “Adhesion test between topcoat layer and undercoat layer”, “After printing” "Cuckle evaluation" was performed. The results are shown in Table 1.

(Example 8)
Example 1 except that “quality paper (trade name: Shiraoi, manufactured by Nippon Paper Industries Co., Ltd.)” was changed to “acidic paper shown below” in “Formation of first layer (undercoat layer)” in Example 1. In the same manner as in Example 1, a recording medium was produced.
The acidic paper is 10 parts of talc pigment, 0.3 parts of commercially available rosin sizing agent, 0 parts of commercially available cationic acrylamide with respect to 100 parts of wood pulp comprising 70 parts of LBKP having a freeness of 450 ml CSF and 30 parts of NBKP having a freeness of 450 ml CSF. 0.03 parts, 0.3 parts of commercially available cationized starch and 0.5 parts of sulfuric acid band were prepared, and then paper-making was carried out at a basis weight of 80 g / m ² using a long net paper machine, and an antioxidant (antioxidant A: 2). , 6-di-t-butyl-p-cresol and antioxidant C: dilauryl thiodipropionate) were obtained by drying with a tab size press to a dry adhesion amount of 2 g / m ² . The antioxidant was dissolved in 150 g of acetone and 300 cc of ethyl acetate in accordance with the respective solubilities, and this was emulsified and dispersed in 300 g of a 10% aqueous polyvinyl alcohol solution with a homogenizer. At this time, 200 cc of a 5% aqueous solution of a surfactant (sodium di-2-ethylhexylsulfosuccinate) was added to the aqueous phase as an emulsifier.
Here, the drying level of the undercoat layer coating liquid (first coating liquid) dried by the hot air dryer treatment was 78%. In addition, as in Example 1, “Cobb water absorption test of fine paper with an undercoat layer”, “Water absorption test of topcoat layer”, “Adhesion test between topcoat layer and undercoat layer”, “After printing” "Cuckle evaluation" was performed. The results are shown in Table 1.

Example 9
“Polyvinyl alcohol as a hydrophilic binder (trade name: PVA245, manufactured by Kuraray Co., Ltd.) added in“ Preparation of coating liquid for second layer (overcoat layer) (second coating liquid) ”in Example 1 , Saponification degree 88%, average degree of polymerization 3,500) "was changed to" acetoacetyl-modified PVA (trade name: Goosefimer Z-100, manufactured by Nippon Synthetic Chemical Industry) "and Example 1 A recording medium was produced in the same manner. The drying level of the undercoat layer coating liquid (first coating liquid) dried by the hot air dryer treatment was 78%. In addition, as in Example 1, “Cobb water absorption test of fine paper with an undercoat layer”, “Water absorption test of topcoat layer”, “Adhesion test between topcoat layer and undercoat layer”, “After printing” "Cuckle evaluation" was performed. The results are shown in Table 1.

(Example 10)
“Polyvinyl alcohol as a hydrophilic binder (trade name: PVA245, manufactured by Kuraray Co., Ltd.) added in“ Preparation of coating liquid for second layer (overcoat layer) (second coating liquid) ”in Example 1 , Saponification degree 88%, average polymerization degree 3,500) "" silanol modified polyvinyl alcohol (trade name: R-1130, manufactured by Kuraray Co., Ltd., polymerization degree 1,700, saponification degree 98.5 mol%) A recording medium was produced in the same manner as in Example 1 except that the above was changed. The drying level of the undercoat layer coating liquid (first coating liquid) dried by the hot air dryer treatment was 78%. In addition, as in Example 1, “Cobb water absorption test of fine paper with an undercoat layer”, “Water absorption test of topcoat layer”, “Adhesion test between topcoat layer and undercoat layer”, “After printing” "Cuckle evaluation" was performed. The results are shown in Table 1.

(Comparative Example 1)
Pulp and internal chemicals were adjusted according to the following composition to produce a base paper having a basis weight of 70 g / m ² .
<Base paper formulation>
LBKP (freeness 440 mlcsf) 70 parts NBKP (freeness 490 mlcsf) 30 parts

<Internal medicine>
Light calcium carbonate (* expressed as ash in base paper) * 8 parts Commercial cationized starch 1.0 parts Commercial cationic polyacrylamide yield improver 0.03 parts

<Composition of undercoat layer coating solution>
For this base paper, a coating solution was prepared with the following composition, and a coating solution was applied at 5 g / m ² on one side at a coating speed of 1200 m / min using a rod metad film press type coating machine. Dried. The drying level of the dried coating solution was 100%.
Commercial first grade kaolin clay 50 parts Commercial heavy calcium carbonate 50 parts Commercial polyacrylic acid dispersant 0.1 part Latex binder 10 parts Commercial phosphate ester starch 10 parts Sodium hydroxide Adjusted to pH 9.6

  For the obtained one, a soft calender finishing device (rigid roll: chilled roll having an outer diameter of 500 mm, elastic roll: resin roll having an outer diameter of 500 mm, linear pressure: 180 kg / cm, temperature: 80 ° C.) is used on-line. A rendering process was applied.

Further, a coating liquid having the following ratio is prepared, and the coating liquid is applied at 10 g / m ² on one side at a coating speed of 1600 m / min using a fountain application / blade type coating machine, and dried to form a multilayer coating. Obtained paper.

<Composition of overcoat layer coating solution>
Commercial first grade kaolin clay 50 parts Commercial heavy calcium carbonate 50 parts Commercial polyacrylic acid dispersant 0.1 part Latex binder 15 parts Commercial phosphoric acid ester starch 3 parts Commercial carboxymethylcellulose thickener (CMC) 0.1 part Hydroxide Sodium adjusted to pH 9.6

  For the obtained multilayer coated paper, an off-line super calender finishing device (number of stages: 10 stages, rigid roll: chilled roll with an outer diameter of 400 mm, elastic roll: cotton roll with an outer diameter of 400 mm, linear pressure: 220 kg / cm) Using this, a calendering process was performed to produce a multi-layer coated paper for offset printing.

(Comparative Example 2)
In Example 1, (1) “second layer (overcoat layer) coating solution” was changed to the coating solution described below, (2) the coating amount per side of the undercoat layer coating solution Changed from 20.0 g / m ² to 10.0 g / m ² , (3) Instead of “drying by hot air dryer treatment”, “drying at 50 ° C. for 3 minutes to form an undercoat layer, A recording medium was manufactured in the same manner as in Example 1 except that the soft calendering process was performed. The drying level of the undercoat layer coating solution (first coating solution) dried at 50 ° C. for 3 minutes was 100%. In addition, as in Example 1, “Cobb water absorption test of fine paper with an undercoat layer”, “Water absorption test of topcoat layer”, “Adhesion test between topcoat layer and undercoat layer”, “After printing” "Cuckle evaluation" was performed. The results are shown in Table 1.

<Coating solution>
60 parts of heavy calcium carbonate (trade name: Escalon # 2000, Sankyo Seimitsu), 20 parts of kaolin (trade name: Milagros, Engelhard: USA), titanium oxide (Taipeke R-780, manufactured by Ishihara Sangyo) 20 parts and 43 parts of 43% sodium polyacrylate (trade name: Aron T-50, manufactured by Toagosei Co., Ltd.) are mixed and dispersed in water using NBK-2 manufactured by Nippon Seiki Seisakusho. 11 parts of styrene-butadiene copolymer latex (trade name: Smartex PA2323, manufactured by Nippon A & L), 3 parts of oxidized starch (trade name: Ace B, manufactured by Oji Cornstarch), and a lubricant ( 1 part of a product name: SN coat 231SP (manufactured by San Nopco) was added to prepare a coating solution for an overcoat layer having a final solid content concentration of 65%.

-Soft calendar processing-
Using a soft calender provided with a roll pair in which a metal roll and a resin roll are paired with respect to the high-quality paper having the undercoat layer formed on the surface, the surface temperature of the metal roll is 80 ° C., the nip pressure is 100 kg / cm, and the speed Soft calendering was performed under the condition of 100 m / min.

From Table 1, the base paper provided with the undercoat layer has a Cobb absorbency of 5.0 g / m ² or less in a contact time of 15 seconds according to a water absorption test specified in JIS P8140, and the contact of the topcoat layer by the Brist method Examples 1 to 10 in which the water absorption amount for 0.5 seconds is 2 mL / m ² or more and 8 mL / m ² or less and the first layer and the second layer are continuously applied are Comparative Examples 1 and 2 In comparison, it can be seen that good quality is obtained with little occurrence of cuckling after image printing, and that the adhesiveness is also excellent. Note that these example samples also had good print quality when an image was ejected by an ink jet printer.

FIG. 1 is an explanatory diagram of a recording medium of the present invention. FIG. 2 is an explanatory diagram of an ink jet recording method using the recording medium of the present invention (part 1). FIG. 3 is an explanatory diagram of an ink jet recording method using the recording medium of the present invention (part 2). FIG. 4 is a diagram for explaining a scanning line of a head filled with a test solution in the Bristow method. FIG. 5 is an explanatory diagram of a conventional recording medium.

Explanation of symbols

11 Fine Paper 12 Solvent Blocking Layer 13 Ink Absorbing Layer 21 Base Paper 22 Solvent Absorbing Layer 100 Recording Medium 200 Inkjet Special Paper

Claims (17)

A base paper, a first layer containing a binder, and a second layer containing a white pigment are sequentially laminated, and the base paper provided with the first layer is based on a water absorption test specified in JIS P8140. contact time is at Cobb water absorption of 15 seconds is 5.0 g / ^{m 2} or less, the second layer, Bristow method by contact time of 0.5 sec water absorption 2 mL / ^{m 2} or more 8 mL / ^{m 2} In the following recording medium manufacturing method, the first coating step of applying the first coating liquid for forming the first layer on the base paper and the first coating step are continuously performed. In particular, a drying step of introducing the coated first coating liquid into a hot air dryer group and drying, and after the drying step, continuously on the dried first coating liquid And a second coating step of coating a second coating liquid for forming the second layer. A method for manufacturing a recording medium.   The method for manufacturing a recording medium according to claim 1, wherein the first coating liquid dried in the drying step has a solid content concentration of 98% or less.   The method for producing a recording medium according to claim 2, wherein the first coating liquid dried in the drying step has a solid concentration of 80% or less.   The method for producing a recording medium according to claim 1, wherein at least one of the first coating liquid and the second coating liquid contains a water-soluble binder.   The method for producing a recording medium according to claim 4, wherein the water-soluble binder is at least one of polyvinyl alcohol and modified polyvinyl alcohol.   6. The method for producing a recording medium according to claim 5, wherein the modified polyvinyl alcohol is acetoacetyl-modified polyvinyl alcohol having a polymerization degree of 1,000 or more.   The method for producing a recording medium according to claim 5, wherein the modified polyvinyl alcohol is silanol-modified polyvinyl alcohol.   The method for producing a recording medium according to any one of claims 4 to 7, wherein at least one of the first coating liquid and the second coating liquid contains a crosslinking agent capable of crosslinking the water-soluble binder.   In the step of applying a coating liquid containing a cross-linking agent capable of cross-linking the water-soluble binder, immediately before applying the coating liquid, a cross-linking agent capable of cross-linking the water-soluble binder is added in-line to the coating liquid. The manufacturing method of the recording medium of Claim 8.   The method for producing a recording medium according to claim 1, wherein the second coating liquid is curtain-coated in the second coating step.   The method for producing a recording medium according to claim 1, wherein the second coating liquid contains a nonionic surfactant.   12. The method for producing a recording medium according to claim 11, wherein the nonionic surfactant is an ethylene oxide adduct of a tertiary alcohol having an acetylene bond in the molecule. At least one of the first coating liquid and the second coating liquid contains an organic solvent, and the organic solvent has a solubility in pure water at 20 ° C. of 1% by mass or more and an SP value of 8. The method for producing a recording medium according to claim 1, wherein 4 (cal / cm ³ ) ^{0.5 to} 13 (cal / cm ³ ) ^0.5 .   The method for producing a recording medium according to any one of claims 1 to 13, wherein the base paper has a Steecht sizing degree defined in JIS P8140 of 30 seconds or more. The method for producing a recording medium according to claim 1, wherein the base paper contains 0.1 to 10 g / m ² of an antioxidant.   A recording medium manufactured by the method for manufacturing a recording medium according to claim 1.   17. An ink drawing process for drawing ink according to predetermined image data on the recording medium according to claim 16, and a dry removal process for drying and removing ink solvent in the recording medium on which the ink has been drawn. An inkjet recording method.