JP2010006044A - Method for manufacturing inkjet recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an inkjet recording medium which has a successful planar shape and excellent ozone resistance, and can inhibit the feathering (feathering with time) of a recorded image and maintain high image density. <P>SOLUTION: This method is to laminate at least a first coating fluid containing an inorganic microparticle and a nitrogen-containing organic cation polymer and a second coating liquid containing an inorganic microparticle and a water-soluble aluminum compound, on a support in that order from the support side. Consequently, an ink receptive layer is formed which features the more content of the nitrogen-containing organic cation polymer and the low content of the water-soluble aluminum compound in the lamina close to the support, compared with the lamina far from the support. In order to achieve this ink receptive layer formation, the method involves the process to apply at least, the first coating liquid and the second coating liquid in a laminar fashion at application temperatures of 35 to 45°C. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an inkjet recording medium.

In recent years, with the rapid development of the information technology industry, various information processing systems have been developed, and recording methods and recording apparatuses suitable for the information processing systems have been developed and put into practical use.
Among these recording methods, the inkjet recording method is capable of recording on a variety of recording materials, has advantages such as being relatively inexpensive and compact in hardware (device), and excellent in quietness. It has also been widely used for so-called home use.

In addition, with the recent increase in resolution of inkjet printers, it has become possible to obtain so-called photographic-like high-quality recorded matter. With the progress of such hardware (devices), inkjet recording media have also become available. Various developments have been made.
The characteristics required for a recording sheet for ink jet recording are generally (1) fast drying (high ink absorption speed), and (2) ink dot diameter is appropriate and uniform. (No blurring), (3) good graininess, (4) high dot roundness, (5) high color density, (6) high chroma (dullness) (7) The water resistance, light resistance and ozone resistance of the printed portion are good, (8) the whiteness of the recording sheet is high, and (9) the storage stability of the recording sheet is good ( Does not cause yellowing coloring even after long-term storage, does not blur images after long-term storage (good aging blur), and (10) resists deformation and has good dimensional stability (small curl) (11) Good hard running performance, etc. That.
Furthermore, in the use of photo glossy paper used for the purpose of obtaining so-called photo-like high-quality recorded matter, in addition to the above properties, gloss, surface smoothness, photographic paper-like texture similar to silver salt photography, etc. Is also required.

In recent years, an ink jet recording medium having a porous structure in the ink receiving layer has been developed and put into practical use for the purpose of improving the various properties described above. Such an ink jet recording medium has a porous structure, and thus has excellent ink receptivity (fast drying property) and high gloss.
For example, there has been proposed an ink jet recording medium containing fine inorganic pigment particles and a water-soluble resin and having an ink receiving layer having a high porosity on a support (see, for example, Patent Documents 1 and 2). .
These recording media, in particular, inkjet recording media provided with an ink receiving layer having a porous structure using silica as inorganic pigment fine particles have excellent ink absorptivity and can form high-resolution images depending on the configuration. It has high ink receiving performance and can exhibit high gloss.

On the other hand, as a component contained in the ink receiving layer, a cationic polymer is known as a component for improving bleeding, and a water-soluble polyvalent metal salt compound is known as a component for improving ozone resistance (for example, Patent Document 3, 4).
Further, a method for suppressing the occurrence of cracks in the ink receiving layer and further improving the productivity is disclosed (for example, see Patent Document 5).
Furthermore, an ink jet recording medium having an ink receiving layer composed of a plurality of layers containing cationic polyurethane and having a layer having a higher concentration of basic aluminum hydroxide compound than the uppermost layer is known (for example, patents). Reference 6).
JP 10-119423 A Japanese Patent Laid-Open No. 10-217601 JP 2002-52812 A JP 2004-351618 A JP 2007-301763 A JP 2007-98610 A

However, when the cationic polymer and the water-soluble polyvalent metal salt compound are contained in the ink receiving layer, the surface state may be deteriorated. In addition, the ink jet recording media described in Patent Documents 5 and 6 may have insufficient improvement in ozone resistance.
The present invention has been made in view of the above, has a good surface shape, can suppress the bleeding (bleeding over time) of the recorded image, can maintain a high image density, and also has ozone resistance. It is an object of the present invention to provide an excellent method for producing an inkjet recording medium.

That is, specific means for solving the above-described problems are as follows.
<1> A first coating liquid containing at least inorganic fine particles and a nitrogen-containing organic cationic polymer, and a second coating liquid containing inorganic fine particles and a water-soluble aluminum compound are formed on the support from the support side. By laminating in order, an ink receiving layer having a higher content of the nitrogen-containing organic cationic polymer and a lower content of the water-soluble aluminum compound in a layer closer to the support than a layer far from the support is formed. As described above, at least the first coating liquid and the second coating liquid are subjected to a multilayer coating process at a coating liquid temperature of 35 ° C. or higher and 45 ° C. or lower.
<2> The method for producing an inkjet recording medium according to <1>, wherein the nitrogen-containing organic cationic polymer is at least one selected from a cationic polyurethane and a cationic polymer having a quaternary ammonium base.

  According to the present invention, an ink jet recording medium having a good surface shape, capable of maintaining a high image density while suppressing bleeding (bleeding over time) of a recorded image, and excellent in ozone resistance. A method can be provided.

Hereinafter, the present invention will be described in detail.
≪Inkjet recording medium manufacturing method≫
The method for producing an ink jet recording medium of the present invention includes a first coating liquid containing at least inorganic fine particles and a nitrogen-containing organic cationic polymer, and a second coating containing inorganic fine particles and a water-soluble aluminum compound on a support. In the layer closer to the layer farther from the support, the content of the nitrogen-containing organic cation polymer in the layer closer to the layer farther from the support is larger, and the liquid is laminated in order from the support side. In order to form an ink-receiving layer with a low content of the water-soluble aluminum compound, at least the first coating liquid and the second coating liquid are applied in multiple layers at a coating liquid temperature of 35 ° C. or higher and 45 ° C. or lower. Including the step of:
The ink jet recording medium manufacturing method of the present invention is an ink jet recording medium having such a structure, which suppresses bleeding (bleeding over time) of a recorded image, maintains a high image density, and has improved ozone resistance. Thus, it is possible to stably manufacture with a good surface shape (for example, suppression of occurrence of cracks).

In the present invention, at least the first coating liquid and the second coating liquid are applied in multiple layers at a coating liquid temperature of 35 ° C. or more and 45 ° C. or less, from the point that a better surface shape is obtained. The coating solution temperature is preferably 38 ° C. or higher and 42 ° C. or lower.
When the coating solution temperature is less than 35 ° C. or exceeds 45 ° C., the surface state of the ink receiving layer formed due to the formation of aggregates or the occurrence of cracks is deteriorated.
For adjusting the coating solution temperature, a commonly performed method can be used without any particular limitation.

<Ink receiving layer>
The ink receiving layer formed by the method for producing an inkjet recording medium of the present invention includes at least a layer formed by a first coating liquid containing inorganic fine particles and a nitrogen-containing organic cationic polymer, inorganic fine particles, and a water-soluble aluminum compound. And a layer formed by a second coating solution containing the layers are sequentially laminated from the support side.

The first coating solution contains at least one inorganic fine particle and at least one nitrogen-containing organic cationic polymer, and if necessary, a water-soluble resin, a sulfur compound, a crosslinking agent, a water-soluble polyvalent metal salt, Other components can be further included. The second coating solution contains at least one inorganic fine particle and at least one water-soluble aluminum compound, and if necessary, a water-soluble resin, a sulfur compound, a crosslinking agent, a water-soluble polyvalent metal salt, Other components can be further included.
Hereinafter, after describing the details of the ink receiving layer in the present invention, the details of the first coating liquid and the second coating liquid will be described.

The ink receiving layer in the present invention is formed by laminating two or more layers, and is a layer closer to the support (hereinafter referred to as “second layer”) than a layer farther from the support (hereinafter sometimes referred to as “second layer”). The first layer is sometimes laminated so that the content of the nitrogen-containing organic cationic polymer is high, and the content of the water-soluble aluminum compound in the first layer is less than that in the second layer. Are stacked.
When laminated so that the content of the nitrogen-containing organic cationic polymer in the second layer is higher than that in the first layer, or the content of the nitrogen-containing organic cationic polymer in the first layer and the second layer is When laminated in the same manner, the density of the recorded image is lowered and the ozone resistance is deteriorated.
Further, when the layers are laminated so that the content of the water-soluble aluminum compound in the second layer is smaller than that in the first layer, or the content of the water-soluble aluminum compound in the first layer and the second layer is When the layers are laminated in the same manner, the surface condition deteriorates due to the occurrence of cracks and the ozone resistance further decreases.

In the present invention, the distribution of the nitrogen-containing organic cationic polymer in the ink receiving layer can be confirmed by elemental analysis. Specifically, mapping analysis by the SEM-EDX method may be performed and the obtained image may be observed. In this case, the presence position of the entire ink receiving layer is confirmed by mapping analysis of the main component (for example, Si element) of the ink receiving layer, and then the mapping analysis of N element is performed to support the layer far from the support of the ink receiving layer. Which of the N element amounts in the layer close to the body is larger is determined by the mapping image.
The presence distribution of the water-soluble aluminum compound in the ink receiving layer can be confirmed in the same manner.

In the present invention, the content ratio of the nitrogen-containing organic cationic polymer in the ink receiving layer (content in the layer far from the support of the ink receiving layer / content in the layer near the support of the ink receiving layer) is 1. It must be less than zero.
From the viewpoint of obtaining the effects of the present invention more effectively, the content ratio is preferably 0 to 0.8, and more preferably 0 to 0.4.
The ink receiving layer containing the nitrogen-containing organic cation polymer in the above content ratio is, for example, the content ratio of the nitrogen-containing organic cation polymer [in the second coating liquid in the method for producing an inkjet recording medium of the present invention described later]. The content / content in the first coating solution] can be formed as described below.

Further, from the viewpoint of obtaining the effects of the present invention more effectively, the content of the nitrogen-containing organic cationic polymer in the first layer in the ink receiving layer is 2 with respect to the total solid content of the first layer. -25% by mass is preferable, 4-20% by mass is more preferable, and 6-18% by mass is particularly preferable.
On the other hand, from the viewpoint of obtaining the effect of the present invention more effectively, the content of the nitrogen-containing organic cationic polymer in the second layer of the ink receiving layer is 1 to 2% of the total solid content of the second layer. 20 mass% is preferable, 2-15 mass% is more preferable, and 4-12 mass% is especially preferable.
Furthermore, from the viewpoint of obtaining the effect of the present invention more effectively, the content of the nitrogen-containing organic cationic polymer in the entire ink receiving layer including the first layer and the second layer is as follows. 1-15 mass% is preferable with respect to the whole total solid, 1.5-12 mass% is more preferable, and 2-10 mass% is especially preferable.
In the present invention, the total solid content of the ink receiving layer refers to all components excluding water from the composition constituting the ink receiving layer.
Further, from the viewpoint of obtaining the effect of the present invention more effectively, the ratio of nitrogen-containing organic cation polymer / inorganic fine particles in the first layer is higher than the ratio of nitrogen-containing organic cation polymer / inorganic fine particles in the second layer. Larger is preferred.

In the present invention, the content ratio of the water-soluble aluminum compound in the ink receiving layer (content in the layer close to the support of the ink receiving layer / content in the layer far from the support of the ink receiving layer) is 1.0. It is necessary to be less than.
From the viewpoint of obtaining the effects of the present invention more effectively, the content ratio is preferably 0 to 0.8, and more preferably 0 to 0.4.
The ink receiving layer containing the water-soluble aluminum compound in the above content ratio is, for example, a content ratio of the water-soluble aluminum compound [content in the first coating solution] in the method for producing an inkjet recording medium of the present invention described later. / Content in the second coating solution] can be formed as described below.

Further, from the viewpoint of obtaining the effect of the present invention more effectively, the content of the water-soluble aluminum compound in the second layer in the ink receiving layer is 2 to 2 with respect to the total solid content of the second layer. 25 mass% is preferable, 4-20 mass% is more preferable, and 6-18 mass% is especially preferable.
On the other hand, from the viewpoint of more effectively obtaining the effects of the present invention, the content of the water-soluble aluminum compound in the second layer of the ink receiving layer is 1 to 20 relative to the total solid content of the second layer. % By mass is preferable, 2 to 15% by mass is more preferable, and 4 to 12% by mass is particularly preferable.
Furthermore, from the viewpoint of obtaining the effect of the present invention more effectively, the content of the water-soluble aluminum compound in the entire ink receiving layer including the first layer and the second layer is as follows. 1 to 15% by mass is preferable, 1.5 to 12% by mass is more preferable, and 2 to 10% by mass is particularly preferable.

  Further, from the viewpoint of improving the glossiness of the ink receiving layer, the ink receiving layer in the present invention is preferably composed of two or more layers, and the uppermost layer farthest from the support contains colloidal silica. Hereinafter, the uppermost layer containing colloidal silica is also referred to as “colloidal silica layer”.

The thickness of the ink receiving layer is preferably determined in relation to the void ratio in the layer from the viewpoint of obtaining an absorption capacity sufficient to absorb all droplets. For example, if the ink amount is 8 nL / mm ² and the porosity is 60%, a film having a layer thickness of about 15 μm or more is required. Considering this point, the thickness of the ink receiving layer is preferably 10 to 50 μm, and more preferably 20 to 40 μm.
Further, the thicknesses of the first layer and the second layer in the present invention are each preferably 5 to 25 μm, and more preferably 10 to 20 μm.
On the other hand, the thickness of the colloidal silica layer that may be contained in the ink receiving layer is preferably 0.05 to 5 μm, more preferably 0.1 to 3 μm, from the viewpoint of ink absorbability and gloss.

The pore diameter of the ink receiving layer is preferably 0.005 to 0.030 μm, more preferably 0.01 to 0.025 μm in terms of median diameter.
The porosity and pore median diameter can be measured using a mercury porosimeter (trade name “Pore Sizer 9320-PC2” manufactured by Shimadzu Corporation).

Further, the ink receiving layer is preferably excellent in transparency, but as a guide, the haze value when the ink receiving layer is formed on a transparent film support is preferably 30% or less, More preferably, it is 20% or less.
The haze value can be measured using a haze meter (HGM-2DP: Suga Test Instruments Co., Ltd.).

  Hereinafter, the nitrogen-containing organic cationic polymer, the inorganic fine particles, and the water-soluble aluminum compound, which are essential components in the first coating liquid and the second coating liquid constituting the ink receiving layer in the present invention, will be described, and subsequently, they are optional components. The water-soluble resin, sulfur compound, magnesium salt, colloidal silica, crosslinking agent, water-soluble polyvalent metal salt, and other components will be described.

(Nitrogen-containing organic cationic polymer)
The ink receiving layer in the invention contains at least one nitrogen-containing organic cationic polymer as an essential component from the viewpoint of suppressing bleeding of the recorded image and from the viewpoint of dispersing silica.
The nitrogen-containing organic cationic polymer in the present invention is not particularly limited, but a polymer having a primary to tertiary amino group or a quaternary ammonium base is preferable.
The nitrogen-containing organic cation polymer is a nitrogen-containing organic cation which is a homopolymer of a monomer having a primary to tertiary amino group and a salt thereof or a quaternary ammonium base (nitrogen-containing organic cation monomer). Conjugated dienes such as polymers, nitrogen-containing organic cationic polymers obtained as copolymers or condensation polymers of the nitrogen-containing organic cationic monomers and other monomers, styrene-butadiene copolymers, methyl methacrylate-butadiene copolymers, etc. Acrylic polymers such as acrylic acid and methacrylic acid ester polymers or copolymers, acrylic acid and methacrylic acid polymers or copolymers; styrene-acrylic acid ester copolymers, styrene Styrene-acrylic polymers such as methacrylate copolymers; ethylene vinyl acetate copolymer Vinyl polymer and the like; the urethane polymer or the like having a urethane bond include a nitrogen-containing organic cation polymers obtained by cationizing modified with a compound containing a cationic group.

  Examples of the nitrogen-containing organic cation monomer include trimethyl-p-vinylbenzylammonium chloride, trimethyl-m-vinylbenzylammonium chloride, triethyl-p-vinylbenzylammonium chloride, triethyl-m-vinylbenzylammonium chloride, N, N -Dimethyl-N-ethyl-Np-vinylbenzylammonium chloride, N, N-diethyl-N-methyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-Nn-propyl-Np -Vinylbenzylammonium chloride, N, N-dimethyl-Nn-octyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N-benzyl-Np-vinylbenzylammonium chloride, N, N- Ethyl-N-benzyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N- (4-methyl) benzyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N-phenyl-N -P-vinylbenzylammonium chloride;

Trimethyl-p-vinylbenzylammonium bromide, trimethyl-m-vinylbenzylammonium bromide, trimethyl-p-vinylbenzylammonium sulfonate, trimethyl-m-vinylbenzylammonium sulfonate, trimethyl-p-vinylbenzylammonium acetate, trimethyl-m-vinyl Benzylammonium acetate, N, N, N-triethyl-N-2- (4-vinylphenyl) ethylammonium chloride, N, N, N-triethyl-N-2- (3-vinylphenyl) ethylammonium chloride, N, N-diethyl-N-methyl-N-2- (4-vinylphenyl) ethylammonium chloride, N, N-diethyl-N-methyl-N-2- (4-vinylphenyl) ethylammonium chloride Tate;

N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-diethylaminopropyl (meth) acrylate, N, N- Methyl chloride, ethyl chloride, methyl bromide of dimethylaminoethyl (meth) acrylamide, N, N-diethylaminoethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N, N-diethylaminopropyl (meth) acrylamide , Quaternized products of ethyl bromide, methyl iodide or ethyl iodide, or sulfonates, alkyl sulfonates, acetates or alkyl carboxylates substituted with their anions.

  Specific examples of the compound include monomethyl diallylammonium chloride, trimethyl-2- (methacryloyloxy) ethylammonium chloride, triethyl-2- (methacryloyloxy) ethylammonium chloride, trimethyl-2- (acryloyloxy) ethylammonium chloride, Triethyl-2- (acryloyloxy) ethylammonium chloride, trimethyl-3- (methacryloyloxy) propylammonium chloride, triethyl-3- (methacryloyloxy) propylammonium chloride, trimethyl-2- (methacryloylamino) ethylammonium chloride, triethyl- 2- (methacryloylamino) ethylammonium chloride, trimethyl-2- (acryloylua) C) ethylammonium chloride, triethyl-2- (acryloylamino) ethylammonium chloride, trimethyl-3- (methacryloylamino) propylammonium chloride, triethyl-3- (methacryloylamino) propylammonium chloride, trimethyl-3- (acryloylamino) Propylammonium chloride, triethyl-3- (acryloylamino) propylammonium chloride;

N, N-dimethyl-N-ethyl-2- (methacryloyloxy) ethylammonium chloride, N, N-diethyl-N-methyl-2- (methacryloyloxy) ethylammonium chloride, N, N-dimethyl-N-ethyl- 3- (acryloylamino) propylammonium chloride, trimethyl-2- (methacryloyloxy) ethylammonium bromide, trimethyl-3- (acryloylamino) propylammonium bromide, trimethyl-2- (methacryloyloxy) ethylammonium sulfonate, trimethyl-3- And (acryloylamino) propylammonium acetate. In addition, examples of copolymerizable monomers include N-vinylimidazole and N-vinyl-2-methylimidazole. In addition, a polymerization unit such as N-vinylacetamide, N-vinylformamide or the like, which is converted into a vinylamine unit by hydrolysis after polymerization, and a salt thereof can be used.

  Examples of the other monomer that can be copolymerized (or polycondensed) with the nitrogen-containing organic cation monomer include basic groups such as primary to tertiary amino groups and salts thereof, or quaternary ammonium bases. Or the monomer which does not contain a cationic part, does not show interaction with the dye in an inkjet ink, or interaction is substantially small is mentioned. For example, (meth) acrylic acid alkyl ester; (meth) acrylic acid cycloalkyl ester such as cyclohexyl (meth) acrylic acid; (meth) acrylic acid aryl ester such as phenyl (meth) acrylate; benzyl (meth) acrylic acid Aralkyl esters of styrene; vinyl aromatics such as styrene, vinyl toluene and α-methyl styrene; vinyl esters such as vinyl acetate, vinyl propionate and vinyl versatate; allyl esters such as allyl acetate; vinylidene chloride, vinyl chloride, etc. Halogen-containing monomers, vinyl cyanides such as (meth) acrylonitrile, olefins such as ethylene and propylene, and the like.

  The (meth) acrylic acid alkyl ester is preferably a (meth) acrylic acid alkyl ester having 1 to 18 carbon atoms in the alkyl moiety, specifically, for example, methyl (meth) acrylate or ethyl (meth) acrylate. Propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, hexyl (meth) acrylate, (meth) Examples include octyl acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, and the like. Among these, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, and hydroxyethyl methacrylate are preferable. The other monomers can also be used alone or in combination of two or more.

  Moreover, as a monomer which comprises a urethane type polymer, the polyvalent isocyanate compound (For example, 2, 4-tolylene diisocyanate, 2, 6-tolylene diisocyanate, m-phenylene diisocyanate, 4,4 which has two or more isocyanate groups). '-Diphenylmethane diisocyanate, hexamethylene diisocyanate, octamethylene diisocyanate, 1,4-cyclohexylene diisocyanate, isophorone diisocyanate, 1,3-bis (isocyanatemethyl) -cyclohexane, 1,5-diisocyanate-2-methylpentane, hydrogenated Xylylene diisocyanate, hydrogenated 4,4′-diphenylmethane diisocyanate, etc.) and a compound that can react with an isocyanate group to form a urethane bond (eg, glycerin) Polyol compounds such as 1,6-hexanediol, triethanolamine, polypropylene glycol, polyethylene glycol, bisphenol A, hydroquinone; succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, maleic anhydride, fumaric acid, 1 , 3-cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalene Acid, biphenylcarboxylic acid, sorbitol, sucrose, aconitic acid, trimellitic acid, hemimellitic acid, phosphoric acid, ethylenediamine, propylenediamine, diethylenetriamine, triisopropanolamine, pyrogallol, Such as hydroxybenzoic acid, hydroxyphthalic acid, 1,2,3-propanetrithiol, ethylenediamine, propylenediamine, hexamethylenediamine, phenylenediamine, tolylenediamine, diphenyldiamine, diaminodiphenylmethane, diaminocyclohexylmethane, piperazine, isophoronediamine Such diamines; and hydrazine).

  Furthermore, examples of the compound that introduces a cationic group into a copolymer or condensate having no cationic group include alkyl halides and methylsulfuric acid.

Among the nitrogen-containing organic cationic polymers described above, from the viewpoint of suppressing bleeding, cationic polyurethanes and cationic polyacrylates described in JP-A No. 2004-167784 are preferable, and cationic polyurethanes are more preferable.
Examples of commercial products of cationic polyurethane include “Superflex 650”, “F-8564D”, “F-8570D” manufactured by Daiichi Kogyo Seiyaku Co., Ltd., “Neofix IJ-150” manufactured by Nikka Chemical Co., Ltd. Or the like.

Further, from the viewpoint of dispersion of inorganic fine particles, polydiallyldimethylammonium chloride and polymethacryloyloxyethyl-β-hydroxyethyldimethylammonium chloride derivatives are preferable, and polydiallyldimethylammonium chloride is more preferable.
Examples of commercially available products include “Charol DC902P” manufactured by Daiichi Kogyo Seiyaku Co., Ltd.

Further, these nitrogen-containing organic cationic polymers can be used in any form of a water-soluble polymer, water-dispersible latex particles, and an aqueous emulsion.
Examples of the aqueous emulsion include a conjugated diene copolymer emulsion; an acrylic polymer emulsion; a styrene-acrylic polymer emulsion; a vinyl polymer emulsion; And those obtained by cationizing the emulsion surface with a cationic surfactant, polymerized under cationic polyvinyl alcohol, and distributing the polyvinyl alcohol on the emulsion surface. Among these cationic emulsions, a cationic polyurethane emulsion whose main component is a urethane emulsion is preferable.

  In the present invention, the nitrogen-containing organic cationic polymer contained in the first coating solution is preferably a cationic polyurethane, more preferably a cationic polyurethane emulsion, from the viewpoint of suppressing bleeding.

(Inorganic fine particles)
The ink receiving layer in the invention contains at least one inorganic fine particle as an essential component.
The inorganic fine particles form a porous structure when the ink receiving layer is formed, and have a role of improving the ink absorption performance.
In particular, if the solid content of the inorganic fine particles in the ink receiving layer is 50% by mass or more, more preferably more than 60% by mass, it is possible to form a more favorable porous structure, and sufficient ink absorption. This is preferable because an ink jet recording medium having the properties can be obtained. Here, the solid content in the ink receiving layer of fine particles is a content calculated based on components other than water in the composition constituting the ink receiving layer.

Examples of the inorganic fine particles in the present invention include silica fine particles, colloidal silica, titanium dioxide, barium sulfate, calcium silicate, zeolite, kaolinite, halloysite, mica, talc, calcium carbonate, magnesium carbonate, calcium sulfate, pseudoboehmite, zinc oxide. Zinc hydroxide, alumina, aluminum silicate, calcium silicate, magnesium silicate, zirconium oxide, zirconium hydroxide, cerium oxide, lanthanum oxide, yttrium oxide and the like. Among these, silica fine particles, colloidal silica, alumina fine particles, or pseudoboehmite are preferable from the viewpoint of forming a good porous structure. The fine particles may be used as primary particles or in a state where secondary particles are formed. The average primary particle size of these fine particles is preferably 2 μm or less, and more preferably 200 nm or less.
Further, silica fine particles having an average primary particle size of 30 nm or less, colloidal silica having an average primary particle size of 30 nm or less, alumina fine particles having an average primary particle size of 20 nm or less, or pseudoboehmite having an average pore radius of 2 to 15 nm is more preferable. In particular, silica fine particles, alumina fine particles, and pseudoboehmite are preferable.

  Silica fine particles are generally roughly classified into wet method particles and dry method (gas phase method) particles according to the production method. In the above wet method, a method is mainly used in which activated silica is produced by acid decomposition of a silicate, and this is appropriately polymerized and agglomerated and precipitated to obtain hydrous silica. On the other hand, the gas phase method is a method by high-temperature gas phase hydrolysis of silicon halide (flame hydrolysis method), a method in which silica sand and coke are heated and reduced by an arc in an electric furnace and oxidized with air. A method of obtaining anhydrous silica by the (arc method) is the mainstream, and “gas phase method silica” means silica (anhydrous silica fine particles) synthesized by the gas phase method. As the silica fine particles used in the present invention, gas phase method silica fine particles are particularly preferable.

The gas phase method silica is different from hydrous silica in terms of the density of silanol groups on the surface, the presence or absence of vacancies, etc., and exhibits different properties, but is suitable for forming a three-dimensional structure with a high porosity. The reason is not clear, in the case of hydrated silica, many density of silanol groups at 5 to 8 / nm ² in the fine particle surface, liable silica fine particles are densely aggregated (aggregation), while the gas phase In the case of the method silica, the density of silanol groups on the surface of the fine particles is 2 to 3 / nm ² , so that it is sparse soft agglomeration (flocculate), resulting in a structure with a high porosity. Is done.

  The above-mentioned vapor phase silica has a particularly large specific surface area, so the ink absorption and retention efficiency is high, and the refractive index is low. Therefore, if the dispersion is made to an appropriate particle size, transparency can be imparted to the receiving layer. It is characterized by high color density and good color development. The transparency of the receiving layer is not only for applications that require transparency, such as OHP, but also in terms of obtaining high color density and good color development gloss even when applied to recording media such as photo glossy paper. is important.

  The average primary particle diameter of the vapor phase silica is preferably 30 nm or less, more preferably 20 nm or less, particularly preferably 10 nm or less, and most preferably 3 to 10 nm. Since the vapor phase silica is easily adhered to each other by hydrogen bonding with a silanol group, a structure having a large porosity can be formed when the average primary particle diameter is 30 nm or less, and ink absorption characteristics are effectively improved. Can be improved.

  Silica fine particles may be used in combination with the other fine particles described above. When the other fine particles and the vapor phase silica are used in combination, the content of the vapor phase silica in all the fine particles is preferably 30% by mass or more, and more preferably 50% by mass or more.

As the inorganic fine particles in the present invention, alumina fine particles, alumina hydrate, a mixture or a composite thereof are also preferable. Of these, alumina hydrate is preferable because it absorbs and fixes ink well, and pseudoboehmite (Al ₂ O ₃ .nH ₂ O) is particularly preferable. Alumina hydrates can be used in various forms, but it is preferable to use sol boehmite as a raw material because a smooth layer can be easily obtained.

About the pore structure of pseudo boehmite, the average pore radius is preferably 1 to 30 nm, and more preferably 2 to 15 nm. The pore volume is preferably 0.3 to 2.0 ml / g, more preferably 0.5 to 1.5 ml / g. Here, the pore radius and pore volume are measured by a nitrogen adsorption / desorption method, and can be measured by, for example, a gas adsorption / desorption analyzer (for example, trade name “Omni Soap 369” manufactured by Coulter). .
Among the alumina fine particles, vapor-phase method alumina fine particles are preferable because of their large specific surface area. The average primary particle size of the vapor phase alumina is preferably 30 nm or less, and more preferably 20 nm or less.

  When the above-mentioned fine particles are used in an ink jet recording medium, for example, JP-A-10-81064, JP-A-10-119423, JP-A-10-157277, JP-A-10-217601, JP-A-11-348409, JP-A-2001-138621. No. 2000-43401 No. 2000-2111235 No. 2000-309157 No. 2001-96897 No. 2001-138627 No. 11-91242 No. 8-2087 No. 8-2090 No. 8-2091, 8-2093, 8-174992, 11-192777, JP-A-2001-301314, and the like can also be preferably used.

(Water-soluble aluminum compound)
As a water-soluble aluminum compound, for example, as an inorganic salt, aluminum chloride or a hydrate thereof, aluminum sulfate or a hydrate thereof, ammonium alum and the like are known. Furthermore, basic polyaluminum hydroxide compounds (hereinafter also referred to as “basic polyaluminum chloride” and “polyaluminum chloride”), which are inorganic aluminum-containing cationic polymers, are known and preferably used.

The basic polyaluminum hydroxide compound has a main component represented by the following general formula 1, 2 or 3, for example, [Al ₆ (OH) ₁₅ ] ³⁺ , [Al ₈ (OH) ₂₀ ] ⁴⁺ , [Al ₁₃ (OH) ₃₄ ] ⁵⁺ , [Al ₂₁ (OH) ₆₀ ] ³⁺ , and the like, which are water-soluble polyaluminum hydroxides that stably contain basic and high-molecular polynuclear condensed ions.

[Al ₂ (OH) _n Cl _6-n ] _m ·· Formula 1
[Al (OH) ₃ ] _n AlCl ₃ .. Formula 2
Al _n (OH) _m Cl _(3n-m) 0 <m <3n Formula 3

  These are water treatment agents from Taki Chemical Co., Ltd. under the name of polyaluminum chloride (PAC), from Asada Chemical Co., Ltd. under the name of polyaluminum hydroxide (Paho), and from Riken Green Co., Ltd. In the name of HAP-25, it is marketed by Daimei Chemical Co., Ltd. under the name of Alpha-In 83 and from other manufacturers for the same purpose, and various grades can be easily obtained.

(Water-soluble resin)
The ink receiving layer in the invention preferably contains at least one water-soluble resin.
Examples of the water-soluble resin include polyvinyl alcohol resins that are resins having a hydroxy group as a hydrophilic structural unit [polyvinyl alcohol (PVA), acetoacetyl-modified polyvinyl alcohol, cation-modified polyvinyl alcohol, anion-modified polyvinyl alcohol, silanol-modified. Polyvinyl alcohol, polyvinyl acetal, etc.], cellulose resins [methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC), hydroxypropyl cellulose (HPC), hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, etc.] , Chitins, chitosans, starch, resins with ether linkages [polyethylene oxide (PEO), Propylene oxide (PPO), polyethylene glycol (PEG), poly ether (PVE)], and resins having carbamoyl groups [polyacrylamide (PAAM), polyvinyl pyrrolidone (PVP), polyacrylic acid hydrazide, etc.] and the like.
Moreover, the polyacrylic acid salt which has a carboxyl group as a dissociable group, maleic acid resin, alginate, gelatins, etc. can be mentioned.

Among these, the water-soluble resin used in the present invention is at least one selected from polyvinyl alcohol resins, cellulose resins, resins having an ether bond, resins having a carbamoyl group, resins having a carboxyl group, and gelatins. In particular, polyvinyl alcohol (PVA) resin is preferable.
Examples of the polyvinyl alcohol include Japanese Patent Publication No. 4-52786, Japanese Patent Publication No. 5-67432, Japanese Patent Publication No. 7-29479, Japanese Patent No. 2537827, Japanese Patent Publication No. 7-57553, Japanese Patent No. 2502998, and Japanese Patent No. 3053231. JP-A-63-176173, JP-A-2604367, JP-A-7-276787, JP-A-9-207425, JP-A-11-58941, JP-A-2000-135858, JP-A-2001-205924, JP 2001-287444, JP 62-278080, JP 9-39373, JP 2750433, JP 2000-158801, JP 2001-213045, JP 2001-328345, JP 8 -324105, JP-A-11-348417, JP-A58-18168 JP, 10-259213, JP 2001-72711, JP 2002-103805, JP 2000-63427, JP 2002-308928, JP 2001-205919, JP 2002-264489. Etc. are mentioned.
Examples of water-soluble resins other than polyvinyl alcohol resins include compounds described in JP-A-11-165461, [0011] to [0012], JP-A-2001-205919, and JP-A-2002-264489. The described compounds are also included.

  These water-soluble resins may be used alone or in combination of two or more. In the present invention, the content of the water-soluble resin is preferably 9 to 40% by mass, and more preferably 12 to 33% by mass with respect to the total solid content of the ink receiving layer.

The water-soluble resin and the inorganic fine particles that mainly constitute the ink receiving layer in the invention may be a single material or a mixed system of a plurality of materials.
From the viewpoint of maintaining transparency, the type of water-soluble resin combined with inorganic fine particles, particularly silica fine particles, is important. When the gas phase method silica is used, the water-soluble resin is preferably a polyvinyl alcohol resin, more preferably a polyvinyl alcohol resin having a saponification degree of 70 to 100%, and a saponification degree of 80 to 99.5. % Of polyvinyl alcohol resin is particularly preferable.

The polyvinyl alcohol-based resin has a hydroxyl group in its structural unit. Since this hydroxyl group and the surface silanol group of the silica fine particle form a hydrogen bond, a three-dimensional network having a secondary particle of the silica fine particle as a network chain unit. It becomes easy to form a structure. By forming this three-dimensional network structure, it is considered that a porous ink receiving layer having a high porosity and sufficient strength is formed.
In ink-jet recording, the porous ink-receiving layer obtained as described above can absorb ink rapidly by capillary action, and can form dots with good roundness without ink bleeding.

  In addition, the polyvinyl alcohol resin may be used in combination with the other water-soluble resin. When the other water-soluble resin and the polyvinyl alcohol resin are used in combination, the content of the polyvinyl alcohol resin in the total water-soluble resin is preferably 50% by mass or more, and more preferably 70% by mass or more.

-Content ratio of inorganic fine particles and water-soluble resin-
By optimizing the mass content ratio [PB ratio (x: y)] of the inorganic fine particles (x) and the water-soluble resin (y), the film structure and film strength of the ink receiving layer can be further improved. It is.

As the mass content ratio [PB ratio (x: y)] in the ink receiving layer, it is possible to prevent a decrease in film strength and cracking during drying caused by the PB ratio being too large, and the PB ratio is When it is too small, the gap is easily blocked by the resin, and the ratio of 1.5: 1 to 10: 1 is preferable from the viewpoint of preventing the ink absorbency from being lowered due to the decrease in the void ratio.
In particular, the x / y ratio of the upper half of the ink receiving layer is equal to or higher than the x / y ratio of the lower half (the PB ratio is the same in the upper half and the lower half, or the lower half is binder-rich). It is particularly preferable that the upper half and the lower half have the same PB ratio.

  Since stress may be applied to the recording medium when passing through the transport system of the ink jet printer, the ink receiving layer needs to have sufficient film strength. Further, when cutting into a sheet shape, the ink receiving layer needs to have sufficient film strength in order to prevent cracking or peeling of the ink receiving layer. In consideration of these cases, the mass ratio (x: y) is more preferably 5: 1 or less, while it is more preferably 2: 1 or more from the viewpoint of ensuring high-speed ink absorbency in an inkjet printer. preferable.

For example, a coating solution in which vapor-phase method silica fine particles having an average primary particle diameter of 20 nm or less and a water-soluble resin are completely dispersed in an aqueous solution at a mass ratio (x: y) of 2: 1 to 5: 1 is provided on the support. When the coating layer is dried, a three-dimensional network structure in which the secondary particles of silica fine particles are network chains is formed, the average pore diameter is 30 nm or less, the porosity is 50 to 80%, the pore ratio A translucent porous film having a volume of 0.5 ml / g or more and a specific surface area of 100 m ² / g or more can be easily formed.

(Sulfur compounds)
The ink receiving layer in the invention preferably contains at least one sulfur compound from the viewpoint of further improving the ozone resistance.
The sulfur compound is at least one selected from thioether compounds, thiourea compounds, disulfide compounds, sulfinic acid compounds, thiocyanic acid compounds, sulfur-containing heterocyclic compounds, and sulfoxide compounds. preferable.

~ Thioether compounds ~
The thioether compound may be a water-soluble compound or an oil-soluble compound. Further, it may be a low molecule or a polymer, and any molecule that contains one or more thioether groups in the molecule may be used.
The thioether compound preferably has 2 or more carbon atoms, more preferably 4 or more.
The thioether-based compound preferably contains an atom (for example, an oxygen atom, a sulfur atom, a nitrogen atom, or a phosphorus atom) containing a lone pair in addition to a sulfur atom, a carbon atom, and a hydrogen atom.
Examples of the thioether-based compound include those represented by the following general formula (1).

R < ₁ >-(S-R < ₃ >) _m- S-R < ₂ > General formula (1)

In the general formula (1), R ₁ and R ₂ each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a group containing them, and R ₁ and R ₂ are the same However, they may be different and may be combined to form a ring. However, at least one of R ₁ and R ₂ is a hydroxyl group, a sulfo group, a carboxy group, a hydrophilic group such as a (poly) ethyleneoxy group, or an amino group, an amide group, an ammonium group, a nitrogen-containing heterocyclic group, or an aminocarbonyl group. , An alkyl group substituted with a group having a basic nitrogen atom such as an aminosulfonyl group or a group containing the same (for example, the substituted alkyl group is further bonded via a divalent linking group such as a carbamoyl group, a carbonyl group, or a carbonyloxy group). And may be bonded to the sulfur atom of the thioether). R ₃ may be substituted and optionally represents an alkylene group having an oxygen atom. m represents an integer of 0 to 10, and when m is 1 or more, at least one sulfur atom bonded to R ₃ may be a sulfoxide group or a sulfonyl group. R ₁ and R ₂ may each be a polymer residue.

Particularly preferred compounds of the general formula (1) are compounds having an alkyl group in which at least one of R ₁ and R ₂ is substituted with a hydroxy group, a carboxy group, an amino group, or an ammonium group. The amino group of the amino group-substituted alkyl group includes an amino group, a monoalkyl (preferably an alkyl group having 1 to 5 carbon atoms) substituted amino group, and a dialkyl (preferably an alkyl group having 1 to 5 carbon atoms) substituted amino group. And a nitrogen-containing heterocyclic group. Specific examples of the compound of the general formula (1) are shown below, but the present invention is not limited to these.

~ Thiourea compounds ~
The thiourea compound may be a water-soluble compound or an oil-soluble compound. Moreover, it may be a low molecule or a polymer, and examples thereof include compounds having one or more structures represented by “> N—C (═S) —N <” in the molecule.

  Such thiourea compounds include thiourea, N-methylthiourea, N-acetylthiourea, 1,3-diphenylthiourea, tetramethylthiourea, guanylthiourea, 4-methylthiosemicarbazide, 1,3-bis (hydroxymethyl)- 2 (3H) benzimidazolethione, 6-hydroxy-1-phenyl-3,4-dihydropyrimidine-2 (1H) -thione, 1-allyl-2-thiourea, 1,3-dimethyl-2-thiourea, 1, Examples include 3-diethyl-2-thiourea, ethylenethiourea, trimethylthiourea, 1-carboxymethyl-2-thiohydantoin, and thiosemicarbazide.

~ Disulfide compounds ~
The disulfide compound may be a water-soluble compound or an oil-soluble compound. Further, it may be a low molecule or a polymer, and for example, a compound represented by the following general formula is preferable, and DL-α-lipoic acid, 4,4′-dithiodimorpholine, and 4,4′-dithiodibutanoic acid are particularly preferable. .

R ₁ —S—S—R ₂

[Wherein, R ₁ and R ₂ are each an organic group containing a carbon atom or a nitrogen atom bonded to a sulfur atom of disulfide. This organic group forms a substituted or unsubstituted aliphatic group, a substituted or unsubstituted aromatic group, or a substituted or unsubstituted heterocyclic group together with the carbon atom or nitrogen atom bonded to the sulfur atom of the disulfide. Even if the carbon atom or nitrogen atom bonded to the sulfur atom of the disulfide is substituted or unsubstituted aliphatic group, aromatic group, heterocyclic group or amino group, and imino group, oxygen atom, yellow atom An organic group to which etc. are bonded may be used. R ₁ and R ₂ may be the same or different and may be combined to form a ring. The substituents for R ₁ and R ₂ are alkyl group, aryl group, heterocyclic group, amino group, amide group, imino group, ammonium group, hydroxy group, sulfo group, carboxy group, aminocarbonyl group or aminosulfonyl group. And a substituent such as a halogen atom. ]

~ Sulfinic acid compounds ~
The sulfinic acid compound may be a water-soluble compound or an oil-soluble compound. Further, it may be a low molecule or a polymer, and any molecule containing at least one sulfinic acid skeleton in the molecule may be used.
The sulfinic acid compound used in the present invention is preferably a compound represented by the following general formula.

_R-SO 2 M

[Wherein, R represents a substituted or unsubstituted alkyl group (preferably having 6 to 30 carbon atoms), a substituted or unsubstituted aryl group (phenyl group, naphthyl group, etc., preferably 6 to 30 carbon atoms), polymer residue Represents a group. M represents a hydrogen atom, an alkali metal atom, or ammonium. ]

  Examples of the substituent of the group represented by R include a linear, branched or cyclic alkyl group (preferably having a carbon number of 1 to 20), an aralkyl group (preferably monocyclic or bicyclic, and a carbon number of the alkyl moiety). 1 to 3), an alkoxy group (preferably 1 to 20 carbon atoms), a 1 or 2 substituted amino group (preferably an alkyl group, acyl group, alkyl or arylsulfonyl group having 1 to 20 carbon atoms, In some cases, the total number of carbon atoms in the substituent is 20 or less), 1 to 3 substituted or unsubstituted ureido groups (preferably 1 to 20 carbon atoms), substituted or unsubstituted aryl groups (preferably carbon A monocyclic or bicyclic ring of 6 to 29), a substituted or unsubstituted arylthio group (preferably 6 to 29 carbon atoms), a substituted or unsubstituted alkylthio group (preferably 1 to 29 carbon atoms), A substituted or unsubstituted alkylsulfoxy group (preferably having a carbon number of 1 to 29), a substituted or unsubstituted arylsulfoxy group (preferably having a carbon number of 6 to 29 and monocyclic or bicyclic), substituted or unsubstituted An alkylsulfonyl group (preferably having a carbon number of 1 to 29), a substituted or unsubstituted arylsulfonyl group (preferably having a carbon number of 6 to 29 and monocyclic or bicyclic), an aryloxy group (preferably having a carbon number of 6 to 29) 29 is monocyclic or bicyclic), carbamoyl group (preferably 1 to 29 carbon atoms), sulfamoyl group (preferably 1 to 29 carbon atoms), hydroxy group, halogen atom (fluorine, chlorine, bromine, iodine), Examples thereof include a sulfonic acid group and a carboxylic acid group.

These substituents further include alkyl groups, aryl groups, alkoxy groups, aryloxy groups, alkylthio groups, arylthio groups, alkylsulfonyl groups, arylsulfonyl groups, carbonamido groups, sulfonamido groups, carbamoyl groups, sulfamoyl groups, alkylsulfo groups. It may have a substituent such as a xyl group, an arylsulfoxy group, an ester group, a hydroxy group, a carboxy group, a sulfo group, or a halogen atom. These groups may be connected to each other to form a ring. These groups may also be part of a homopolymer or copolymer chain.
Specific examples of the sulfinic acid compound are shown below.

~ Thiocyanic acid compounds ~
Examples of the thiocyanate compound include methyl thiocyanate, ethyl thiocyanate, sodium thiocyanate, potassium thiocyanate, calcium thiocyanate, and the like.

~ Sulfur-containing heterocyclic compounds ~
As the sulfur-containing heterocyclic compound, a compound containing a sulfur atom as one of atoms constituting the heterocyclic ring, a heterocyclic substituted mercapto compound, and a mercapto group of a heterocyclic substituted mercapto compound are an alkyl group, an aryl group, an acyl group, a sulfonyl group. Examples thereof include compounds substituted with a group and the like, and among these, compounds represented by the following general formula are preferred.

[Wherein, X represents a nonmetallic atom group necessary for forming a 5- to 7-membered ring. The nonmetal atom group may have a substituent, and examples of the substituent include an alkyl group, an alkenyl group, an aryl group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, a hydroxyl group, an amino group, Examples include a mercapto group, a carboxyl group, an acyl group, a carbamoyl group, a sulfamoyl group, a halogen atom, and a cyano group. These substituents may further have a substituent.
M represents a hydrogen atom, an ammonium ion, or a metal atom. In addition, a group containing a 5- to 7-membered ring constituted by containing X may be condensed with other components to form a condensed ring. ]
Specific examples of the heterocyclic substituted mercapto compound include compounds (1-1 to 1-32) described in paragraphs [0027] to [0032] of JP-A-2000-94829.

~ Sulphoxide compounds ~
The sulfoxide compound may be a water-soluble compound or an oil-soluble compound. Further, it may be a low molecule or a polymer, and any molecule that contains one or more sulfoxide groups in the molecule may be used.
The sulfoxide compound preferably has 2 or more carbon atoms, more preferably 4 or more.
In addition to the sulfoxide group, carbon atom, and hydrogen atom, the sulfoxide-based compound preferably further contains an atom containing a lone pair (for example, an oxygen atom, a sulfur atom, a nitrogen atom, or a phosphorus atom).
Specific compounds are shown below.

  Furthermore, as the sulfur-containing compound used in the present invention, sulfone compounds, sulfonamide compounds, thioester compounds, thioamide compounds, sulfonic acid compounds, thiosulfonic acid compounds, thiosulfinic acid compounds, sulfamine compounds, Examples include thiocarbamic acid compounds and sulfite compounds.

  Among the sulfur compounds described above, thioether compounds or sulfoxide compounds are preferable.

At this time, there is no particular limitation on the form in which the sulfur-based compound is contained in the ink receiving layer, but from the viewpoint of keeping the density of the recorded image higher, the sulfur-based compound is the second in the ink receiving layer. A form that is contained so as to be contained in the first layer more than the layer is preferable.
That is, the content ratio of the sulfur-based compound in the ink receiving layer [content in the second layer / content in the first layer] is preferably less than 1.0, more preferably 0 to 0.6. 0 (that is, a form in which a sulfur compound is not contained in a layer far from the support) is particularly preferable.
More preferably, the content ratio of the sulfur compound [content in the second layer / content in the first layer] is 0 to 0.6, and the content ratio of the nitrogen-containing organic cationic polymer [second Content in the first layer / content in the first layer] is 0 to 0.8.

Furthermore, in the present invention, the sulfur compound in the ink receiving layer is a thioether compound or a sulfoxide compound, and the nitrogen-containing organic cationic polymer is at least one selected from cationic polymers having a cationic urethane and a quaternary ammonium base. It is preferable that
More preferably, the sulfur compound in the ink receiving layer is a thioether compound or a sulfoxide compound, and the content ratio of sulfur compound (content in the second layer / content in the first layer) is 0. To 0.6, and the nitrogen-containing organic cationic polymer is at least one selected from cationic urethane and a cationic polymer having a quaternary ammonium base, and the content ratio of the nitrogen-containing organic cationic polymer [second layer Content / in the first layer] is 0 to 0.8.

  In the present invention, the presence distribution of the sulfur compound in the ink receiving layer can be confirmed by elemental analysis. Specifically, mapping analysis by the SEM-EDX method may be performed and the obtained image may be observed. In this case, the presence position of the entire ink receiving layer is confirmed by mapping analysis of the main component (for example, Si element) of the ink receiving layer, and then the mapping analysis of S element is performed, and the first layer and the first layer in the ink receiving layer Which of the S element amounts in the second layer is larger is determined from the mapping image.

Further, from the viewpoint of further improving the ozone resistance and keeping the image density higher, the content of the sulfur compound in the first layer in the ink receiving layer may be the total solid content of the first layer. On the other hand, 1-20 mass% is preferable, 3-15 mass% is more preferable, and 4-10 mass% is especially preferable.
On the other hand, from the viewpoint of keeping the density of the recorded image higher, the content of the sulfur-based compound in the second layer in the ink receiving layer is 0 to 5 relative to the total solid content of the second layer. % By mass is preferable, 0 to 3% by mass is more preferable, and 0% by mass (that is, a form in which the second layer does not contain a sulfur compound) is particularly preferable.
Furthermore, from the viewpoint of further improving the ozone resistance and maintaining the image density higher, the content of the sulfur-based compound in the entire ink receiving layer including the second layer and the first layer is as follows. Is preferably 0.5 to 5% by mass, more preferably 1 to 4% by mass, and particularly preferably 1.5 to 3% by mass with respect to the total solid content of the entire ink receiving layer.

(Magnesium salt)
The ink receiving layer in the invention preferably contains at least one magnesium salt from the viewpoint of further improving the ozone resistance.
Examples of the magnesium salt include magnesium acetate, magnesium oxalate, magnesium sulfate, magnesium chloride hexahydrate, and magnesium citrate nonahydrate.
Of these, magnesium chloride hexahydrate is preferred.

  Examples of commercially available magnesium salts include “White Nigari NS” and “Mag Chloride (Special Name) NS” manufactured by Naikai Shigyo Co., Ltd.

  Further, from the viewpoint of obtaining the effect of the present invention more effectively, the content of the magnesium salt in the ink receiving layer is preferably 0.05 to 5% by mass, more preferably 0.1 to 3% by mass. Preferably, 0.2-2 mass% is especially preferable.

(Colloidal silica)
When the ink receiving layer in the present invention has a colloidal silica layer as the uppermost layer, the average primary particle size of the colloidal silica used is preferably 10 nm to 200 nm, more preferably 50 nm to 150 nm.
In addition, the colloidal silica in the present invention is preferably anionic and nonionic. An anionic property is particularly preferable. The ^{content, 0.01g / m 2 ~5g / m} 2 is preferred. 0.05 g / m ² to ² g / m ² is particularly preferable.

(Crosslinking agent)
The ink receiving layer in the invention preferably contains at least one crosslinking agent from the viewpoint of crosslinking the water-soluble resin.
In particular, the ink receiving layer in the invention is preferably a porous layer in which the inorganic fine particles and the water-soluble resin are used in combination, and further cured by a cross-linking reaction between the cross-linking agent and the water-soluble resin.

Boron compounds are preferred for the crosslinking of the water-soluble resin, particularly polyvinyl alcohol. Examples of the boron compound include borax, boric acid, borate (for example, orthoborate, InBO ₃ , ScBO ₃ , YBO ₃ , LaBO ₃ , Mg ₃ (BO ₃ ) ₂ , Co ₃ (BO ₃ ) ₂ , two Borate (eg, Mg ₂ B ₂ O ₅ , Co ₂ B ₂ O ₅ ), metaborate (eg, LiBO ₂ , Ca (BO ₂ ) ₂ , NaBO ₂ , KBO ₂ ), tetraborate (eg, Na ₂ B ₄ O ₇ · 10H ₂ O), pentaborate (for example, KB ₅ O ₈ · 4H ₂ O, Ca ₂ B ₆ O ₁₁ · 7H ₂ O, CsB ₅ O ₅ ), etc. Of these, borax, boric acid, and borate are preferable, and boric acid is particularly preferable in that a crosslinking reaction can be promptly caused.

The following compounds other than the boron compound can also be used as a crosslinking agent for the water-soluble resin.
For example, aldehyde compounds such as formaldehyde, glyoxal, and glutaraldehyde; ketone compounds such as diacetyl and cyclopentanedione; bis (2-chloroethylurea) -2-hydroxy-4,6-dichloro-1,3,5- Active halogen compounds such as triazine and 2,4-dichloro-6-S-triazine sodium salt; divinylsulfonic acid, 1,3-vinylsulfonyl-2-propanol, N, N′-ethylenebis (vinylsulfonylacetamide) ), Active vinyl compounds such as 1,3,5-triacryloyl-hexahydro-S-triazine; N-methylol compounds such as dimethylolurea and methyloldimethylhydantoin; melamine resins (for example, methylolmelamine, alkylated methylolmelamine) ;Epoxy resin;

Isocyanate compounds such as 1,6-hexamethylene diisocyanate; aziridine compounds described in US Pat. Nos. 3,017,280 and 2,983611; carboximide compounds described in US Pat. No. 3,100,704; glycerol triglycidyl Epoxy compounds such as ether; Ethyleneimino compounds such as 1,6-hexamethylene-N, N′-bisethyleneurea; Halogenated carboxaldehyde compounds such as mucochloric acid and mucophenoxycyclolic acid; 2,3-dihydroxy Dioxane-based compounds such as dioxane; titanium-containing aluminum sulfate, chromium alum, potassium alum, metal-containing compounds such as zirconyl acetate, chromium acetate, polyamine compounds such as tetraethylenepentamine, hydrazide compounds such as adipic acid dihydrazide, A low molecule or polymer containing two or more oxazoline groups can be used.
Said crosslinking agent may be used individually by 1 type, and may be used in combination of 2 or more type.
1-50 mass% is preferable with respect to water-soluble resin, and, as for the usage-amount of a crosslinking agent, 5-40 mass% is more preferable.

(Water-soluble polyvalent metal salt)
The ink receiving layer in the invention preferably contains at least one water-soluble polyvalent metal compound in addition to the magnesium salt. For example, the water-soluble polyvalent metal compound functions as a mordant to further improve the ozone property.

The water-soluble polyvalent metal compound used in the present invention is preferably a trivalent or higher valent metal compound. For example, a water-soluble salt of a metal selected from calcium, barium, manganese, copper, cobalt, nickel, aluminum, iron, zinc, zirconium, chromium, tungsten, and molybdenum can be given.
Specifically, for example, calcium acetate, calcium chloride, calcium formate, calcium sulfate, calcium butyrate, barium acetate, barium sulfate, barium phosphate, barium oxalate, barium naphthoresorcin carboxylate, barium butyrate, manganese chloride, manganese acetate, Manganese formate dihydrate, manganese ammonium sulfate hexahydrate, cupric chloride, ammonium copper (II) chloride dihydrate, copper sulfate, copper (II) butyrate, copper oxalate, copper phthalate, copper citrate , Copper gluconate, copper naphthenate, cobalt chloride, cobalt thiocyanate, cobalt sulfate, cobalt acetate (II), cobalt naphthenate, nickel sulfate hexahydrate, nickel chloride hexahydrate, nickel acetate tetrahydrate, sulfuric acid Nickel ammonium hexahydrate, nickel amidosulfate tetrahydrate, nitric acid sulfamate , Nickel 2-ethylhexanoate, aluminum sulfate, aluminum sulfite, aluminum thiosulfate, polyaluminum chloride, aluminum nitrate nonahydrate, aluminum chloride hexahydrate, aluminum acetate, aluminum lactate, basic aluminum thioglycolate, Ferrous bromide, ferrous chloride, ferric chloride, ferrous sulfate, ferric sulfate, iron (III) citrate, iron (III) lactate trihydrate, iron triammonium trioxalate ( III) Trihydrate, zinc bromide, zinc chloride, zinc nitrate hexahydrate, zinc sulfate, zinc acetate, zinc lactate, zirconium acetate, zirconyl acetate, zirconium tetrachloride, zirconium chloride, zirconium chloride octahydrate , Hydroxy zirconium chloride, chromium acetate, chromium sulfate, sodium phosphotungstate, sodium citrate Nungsten, 12 tungstophosphoric acid n hydrate, 12 tungstophosphoric acid 26 hydrate, molybdenum chloride, 12 molybdophosphoric acid n hydrate, aluminum alum, basic polyaluminum hydroxide, zinc phenolsulfonate, zinc acetate And ammonium and zinc ammonium carbonate. Two or more of these water-soluble polyvalent metal compounds may be used in combination. In the present invention, the water solubility in the water-soluble polyvalent metal compound means that 1% by weight or more dissolves in 20 ° C. water.

  Among the above water-soluble polyvalent metal compounds, an aluminum compound or a compound composed of a Group 4A metal (for example, zirconium or titanium) in the periodic table is preferable, and an aluminum compound is more preferable. Particularly preferred is a water-soluble aluminum compound. The details of the water-soluble aluminum compound are as described above.

  As the water-soluble compound containing the Group 4A element of the periodic table, a water-soluble compound containing titanium or zirconium is more preferable. Examples of the water-soluble compound containing titanium include titanium chloride, titanium sulfate, titanium tetrachloride, tetraisopropyl titanate, titanium acetylacetonate, and titanium lactate. Water-soluble compounds containing zirconium include zirconium acetate, zirconyl acetate, zirconium chloride, hydroxy zirconium chloride, zirconium nitrate, zirconyl nitrate, basic zirconium carbonate, zirconium hydroxide, zirconium lactate, zirconyl lactate, zirconium / ammonium carbonate, zirconium carbonate -Potassium, zirconyl carbonate / ammonium carbonate, zirconyl carbonate / potassium carbonate, zirconium sulfate, zirconium fluoride, zirconyl sulfate, zirconyl fluoride and the like.

  The above-mentioned water-soluble polyvalent metal compound is preferably added at a ratio of 0.1 to 10% by mass, more preferably 0.5 to 8% by mass with respect to the inorganic fine particles.

(Other ingredients)
The ink receiving layer in the invention may contain other components such as a mordant other than the nitrogen-containing organic cationic polymer, magnesium salt, and water-soluble polyvalent metal salt, and various surfactants.
As other components, the components described in paragraph numbers 0088 to 0117 in JP-A-2005-14593, the components described in paragraph numbers 0138 to 0155 in JP-A-2006-321176, and the like are included. Can be appropriately selected and used.

<Support>
As the support in the present invention, any of a transparent support made of a transparent material such as plastic and an opaque support made of an opaque material such as paper can be used. In order to make use of the transparency of the ink receiving layer, it is preferable to use a transparent support or a highly glossy opaque support. Further, a read-only optical disk such as a CD-ROM or DVD-ROM, a write-once optical disk such as a CD-R or DVD-R, or a rewritable optical disk may be used as a support to provide an ink receiving layer on the label surface side. it can.

The material that can be used for the transparent support is preferably a material that is transparent and can withstand radiant heat when used in an OHP or backlight display. Examples of the material include polyesters such as polyethylene terephthalate (PET); polysulfone, polyphenylene oxide, polyimide, polycarbonate, polyamide and the like. Of these, polyesters are preferable, and polyethylene terephthalate is particularly preferable.
Although there is no restriction | limiting in particular as thickness of the said transparent support body, 50-200 micrometers is preferable at the point which is easy to handle.

  As the highly glossy opaque support, one having a glossiness of 40% or more on the surface on which the ink receiving layer is provided is preferable. The glossiness is a value determined according to the method described in JIS P-8142 (75-degree specular gloss test method for paper and paperboard). Specifically, the following supports are mentioned.

For example, high gloss paper support such as art paper, coated paper, cast coated paper, baryta paper used for silver salt photographic support, polyester such as polyethylene terephthalate (PET), nitrocellulose, cellulose acetate , Cellulose esters such as cellulose acetate butyrate, and plastic films such as polysulfone, polyphenylene oxide, polyimide, polycarbonate, and polyamide are made opaque by adding a white pigment or the like (surface calendering may be applied). Glossy film; or a support in which a polyolefin coating layer containing or not containing a white pigment is provided on the surface of a highly glossy film containing the various paper supports, the transparent support or the white pigment. Etc.
A white pigment-containing foamed polyester film (for example, foamed PET containing polyolefin fine particles and forming voids by stretching) can also be suitably exemplified. Furthermore, resin-coated paper used for silver salt photographic printing paper is also suitable.

  Although there is no restriction | limiting in particular also about the thickness of the said opaque support body, 50-300 micrometers is preferable at the point of handleability.

  The surface of the support may be subjected to corona discharge treatment, glow discharge treatment, flame treatment, ultraviolet irradiation treatment or the like in order to improve wettability and adhesion.

Next, the base paper used for the resin-coated paper will be described in detail.
The base paper is made from wood pulp as a main raw material and, if necessary, paper using synthetic pulp such as polypropylene or synthetic fibers such as nylon or polyester in addition to wood pulp. As the above-mentioned wood pulp, any of LBKP, LBSP, NBKP, NBSP, LDP, NDP, LUKP, NUKP can be used, but more LBKP, NBSP, LBSP, NDP, LDP with more short fibers are used. preferable.
However, the ratio of LBSP and / or LDP is preferably 10% by mass or more and 70% by mass or less.

  The pulp is preferably a chemical pulp (sulfate pulp or sulfite pulp) with few impurities, and a pulp having a whiteness improved by bleaching is also useful.

  In the base paper, sizing agents such as higher fatty acids and alkyl ketene dimers, white pigments such as calcium carbonate, talc and titanium oxide, paper strength enhancing agents such as starch, polyacrylamide and polyvinyl alcohol, fluorescent whitening agents, polyethylene glycols A water retaining agent such as a dispersant, a softening agent such as a quaternary ammonium, and the like can be appropriately added.

  The freeness of the pulp used for papermaking is preferably 200 to 500 ml as defined by CSF, and the fiber length after beating is a 24 mesh residual mass% and a 42 mesh residual as defined in JIS P-8207. 30 to 70% of the sum with the mass% of is preferable. In addition, it is preferable that the mass% of 4 mesh remainder is 20 mass% or less.

The basis weight of the base paper is preferably 30 to 250 g, and particularly preferably 50 to 200 g. The thickness of the base paper is preferably 40 to 250 μm. The base paper can be given a high smoothness by calendering at the paper making stage or after paper making. The density of the base paper is generally 0.7 to 1.2 g / m ² (JIS P-8118).
Furthermore, the base paper stiffness is preferably 20 to 200 g under the conditions specified in JIS P-8143.

A surface sizing agent may be applied to the surface of the base paper. As the surface sizing agent, a sizing agent similar to the size that can be added to the base paper can be used.
The pH of the base paper is preferably 5 to 9 when measured by a hot water extraction method defined in JIS P-8113.

  The polyethylene covering the front and back surfaces of the base paper is mainly low-density polyethylene (LDPE) and / or high-density polyethylene (HDPE), but some other LLDPE, polypropylene, etc. can also be used.

  In particular, the polyethylene layer on the side that forms the ink receiving layer is added with rutile or anatase type titanium oxide, fluorescent whitening agent, ultramarine, and polyethylene, as is widely done in photographic paper. Those having improved whiteness and hue are preferred. Here, as a titanium oxide content, about 3-20 mass% is preferable with respect to polyethylene, and 4-13 mass% is more preferable. Although the thickness of a polyethylene layer does not have limitation in particular, 10-50 micrometers is suitable for both front and back layers. Further, an undercoat layer can be provided on the polyethylene layer in order to provide adhesion to the ink receiving layer. As the undercoat layer, aqueous polyester, gelatin and PVA are preferable. Moreover, as thickness of this undercoat layer, 0.01-5 micrometers is preferable.

  Polyethylene-coated paper can be used as glossy paper, or when it is melt-extruded onto the surface of the base paper and coated, the matte surface or silky surface that can be obtained with ordinary photographic printing paper by so-called molding Can also be used.

A back coat layer can be provided on the support, and examples of components that can be added to the back coat layer include a white pigment, an aqueous binder, and other components.
Examples of white pigments contained in the backcoat layer include light calcium carbonate, heavy calcium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin white, and aluminum silicate. , Diatomaceous earth, calcium silicate, magnesium silicate, synthetic amorphous silica, colloidal silica, colloidal alumina, pseudoboehmite, aluminum hydroxide, alumina, lithopone, zeolite, hydrous halloysite, magnesium carbonate, magnesium hydroxide, white inorganic pigment, styrene And organic pigments such as polyethylene plastic pigments, acrylic plastic pigments, polyethylene, microcapsules, urea resins, and melamine resins.

Examples of the aqueous binder used in the backcoat layer include styrene / maleate copolymer, styrene / acrylate copolymer, polyvinyl alcohol, silanol-modified polyvinyl alcohol, starch, cationized starch, casein, gelatin, carboxy Examples thereof include water-soluble polymers such as methyl cellulose, hydroxyethyl cellulose, and polyvinyl pyrrolidone, and water-dispersible polymers such as styrene butadiene latex and acrylic emulsion.
Examples of other components contained in the back coat layer include antifoaming agents, foam suppressors, dyes, fluorescent brighteners, preservatives, and water resistance agents.

<Others>
The ink jet recording medium of the present invention may further have an ink solvent absorbing layer, an intermediate layer, a protective layer and the like in addition to the ink receiving layer. Further, an undercoat layer may be provided on the support for the purpose of improving the adhesion between the ink receiving layer and the support and appropriately adjusting the electric resistance value.

  A polymer fine particle dispersion may be added to a constituent layer (for example, an ink receiving layer or a back coat layer) of the ink jet recording medium of the present invention. This polymer fine particle dispersion is used for the purpose of improving film properties such as dimensional stabilization, curling prevention, adhesion prevention, and film cracking prevention. The polymer fine particle dispersion is described in JP-A-62-245258 and JP-A-10-228076. If a polymer fine particle dispersion having a low glass transition temperature (40 ° C. or lower) is added to the layer containing the mordant, cracking and curling of the layer can be prevented. Further, even when a polymer fine particle dispersion having a high glass transition temperature is added to the back layer, curling can be prevented.

  The ink receiving layer may be provided only on one side of the support, or may be provided on both sides of the support for the purpose of preventing deformation such as curling. When the ink receiving layer is provided only on one side of the support, the anti-reflection film may be provided on the opposite side surface or both sides for the purpose of increasing light transmission. .

  In addition, by applying boric acid or a boron compound to the surface of the support on the side where the ink receiving layer is provided, and forming an ink receiving layer thereon, the glossiness and surface smoothness of the ink receiving layer can be improved. In addition, it is possible to suppress aging blurring of an image after printing in a high temperature and high humidity environment.

  According to a first aspect of the method for producing an ink jet recording medium of the present invention, a first coating liquid containing at least inorganic fine particles and a nitrogen-containing organic cationic polymer on a support, inorganic fine particles, and a water-soluble aluminum compound are provided. A step of forming a coating layer by coating the second coating solution containing a coating layer in order from the support side at a coating solution temperature of 35 ° C. or higher and 45 ° C. or lower, and (1) at least the first coating layer. (2) During the drying of the coating layer formed by applying at least the first coating liquid and the second coating liquid at the same time as applying the first coating liquid and the second coating liquid. A step of applying a liquid containing a basic compound and crosslinking and curing the coating layer at any time before the coating layer exhibits reduced-rate drying, and the coating layer is crosslinked and cured. The nitrogen-containing organic cationic polymer It includes many in the layer closer to the support than the layer furthest from the support, in a form than a layer nearer the water-soluble aluminum compound to the support to form an ink-receiving layer containing a large amount in the layer furthest from the support.

The second embodiment of the method for producing an ink jet recording medium of the present invention includes a first coating liquid containing at least inorganic fine particles and a nitrogen-containing organic cationic polymer, inorganic fine particles, and water-soluble aluminum on a support. A step of forming a coating layer by coating the second coating solution containing the compound in order from the support side, with the coating solution temperature being 35 ° C. or higher and 45 ° C. or lower;
Cooling the formed coating layer so as to decrease by 5 ° C. or more with respect to the lower one of the temperature of the first coating solution at the time of coating and the temperature of the second coating solution at the time of coating; Forming an ink-receiving layer by drying the cooled coating layer, and forming an ink-receiving layer containing more nitrogen-containing organic cationic polymer in a layer closer to the support than in a layer far from the support It is a form to do.

  By forming the inkjet recording medium production method of the present invention as in the first form or the second form, the layer containing the nitrogen-containing organic cationic polymer is closer to the support than the layer far from the support. The ink receiving layer can be formed so as to be contained in a large amount. As a result, it is possible to produce an ink jet recording medium that can maintain a high image density while suppressing bleeding (bleeding over time) of the recorded image, is excellent in ozone resistance, and has a good surface shape.

<Coating layer forming step>
The first form and the second form contain at least a first coating liquid containing inorganic fine particles and a nitrogen-containing organic cationic polymer, inorganic fine particles, and a water-soluble aluminum compound on a support. A step of forming a coating layer by coating the first coating solution in order from the support side at a coating solution temperature of 35 ° C. or more and 45 ° C. or less (hereinafter, this step may be referred to as “coating layer forming step”). ).
In the coating layer forming step, it is necessary to apply at least a plurality of coating liquids of the first coating liquid and the second coating liquid in this order on the support, but if necessary, Other coating liquids may be applied on the second coating liquid. A barrier layer coating solution (intermediate layer coating solution) may be interposed between the coating solutions.

The form of applying the first coating liquid and the second coating liquid (and other coating liquids as required) is not particularly limited, and each liquid is simultaneously applied by a known method to form a coating layer. Alternatively, the coating layers may be formed by coating each solution one by one (sequential coating) by a known method.
The simultaneous multilayer coating can be performed using a known coating apparatus such as an extrusion die coater or a curtain flow coater.
The sequential coating can be performed using a known coating apparatus such as an extrusion die coater, an air doctor coater, a bread coater, a rod coater, a knife coater, a squeeze coater, a reverse roll coater, or a bar coater.

Here, a preferable coating amount of each coating solution will be described.
The wet coating amount of the first coating solution is preferably ^{50~200ml / m 2, 75~150ml / m} 2 is more preferable. Moreover, as a solid content application quantity of a 1st coating liquid, 5-25 g / m < ² > is preferable and 10-18 g / m < ² > is more preferable.
The wet coating amount of the second coating solution is preferably ^{50~200ml / m 2, 75~150ml / m} 2 is more preferable. Moreover, as a solid content application quantity of a 2nd coating liquid, 5-25 g / m < ² > is preferable and 10-18 g / m < ² > is more preferable.
Other coating liquid, for example, when using a coating solution containing colloidal silica, the wet coating amount of the coating, preferably 10~150ml / ^{m 2,} more preferably 20~100 ml / ^{m 2.} Moreover, as solid content coating amount of this coating liquid, 0.01-10 g / m < ² > is preferable and 0.05-5 g / m < ² > is more preferable.
Hereinafter, the first coating solution, the second coating solution, and other coating solutions used as necessary will be described.

(First coating solution)
The first coating liquid contains at least one inorganic fine particle and at least one nitrogen-containing organic cationic polymer.
The details of the inorganic fine particles in the first coating liquid are as described for the inorganic fine particles in the ink receiving layer. Moreover, there is no restriction | limiting in particular as content rate of the inorganic fine particle in a 1st coating liquid, However, It is preferable that it is 50-90 mass% with respect to the total solid of a 1st coating liquid, and 60-80 mass%. It is more preferable that
In the present invention, the total solid content in the first coating liquid refers to all components excluding water from the first coating liquid. The same applies to other liquids.

The nitrogen-containing organic cationic polymer contained in the first coating liquid in the present invention is preferably at least one selected from cationic polyurethanes and cationic polymers having a quaternary ammonium base from the viewpoint of suppressing bleeding. A cationic polyurethane is more preferable.
The nitrogen-containing organic cationic polymer is preferably contained in the first coating liquid in the form of an aqueous emulsion, and more preferably contained in the first coating liquid in the form of an aqueous emulsion of cationic polyurethane.

  In addition, the first coating liquid in the present invention preferably further contains a nitrogen-containing organic cationic polymer other than cationic polyurethane from the viewpoint of dispersibility of the inorganic fine particles. Polydiallyldimethylammonium chloride, polymethacryloyloxyethyl-β It is more preferable to further contain at least one selected from hydroxyethyldimethylammonium chloride derivatives, and it is more preferable to further contain polydiallyldimethylammonium chloride.

  In addition, from the viewpoint of more effectively obtaining the effects of the present invention, the content of the nitrogen-containing organic cationic polymer in the first coating liquid is 1 to 20 mass relative to the total solid content of the first coating liquid. % Is preferable, 2 to 15% by mass is more preferable, and 4 to 12% by mass is particularly preferable.

The first coating liquid preferably further contains a sulfur compound from the viewpoint of further improving the ozone resistance.
In this case, from the viewpoint of obtaining the effect of the present invention more effectively, the content of the sulfur-based compound in the first coating liquid is 1 to 20 mass relative to the total solid content of the first coating liquid. % Is preferable, 3 to 15% by mass is more preferable, and 4 to 10% by mass is particularly preferable.

In addition to the essential components, the first coating solution may further contain other components such as a water-soluble resin, a crosslinking agent, a water-soluble polyvalent metal salt, a mordant, a dispersant, and a surfactant. .
In the application of the first coating solution, it is also preferable to apply the solution after in-line mixing a solution containing the water-soluble polyvalent metal salt (preferably basic polyaluminum chloride).
Details of each component such as a sulfur-based compound, a water-soluble resin, a cross-linking agent, a mordant, and a water-soluble polyvalent metal salt are as described in the section of <Ink Receptive Layer>, and preferred forms are also the same. . The dispersant will be described later.

  The first coating solution is preferably acidic, and the pH is preferably 5.0 or less, more preferably 4.5 or less, and even more preferably 4.0 or less. The pH of the first coating solution can be adjusted by appropriately selecting the type and addition amount of the cationic polymer. Moreover, you may adjust by adding an organic or inorganic acid. When the pH of the first coating solution is 5.0 or less, for example, the crosslinking reaction of the water-soluble resin by the crosslinking agent (particularly boron compound) in the first coating solution can be more sufficiently suppressed.

-Preparation method of first coating liquid-
In the present invention, the first coating liquid containing at least inorganic fine particles and a nitrogen-containing organic cationic polymer can be prepared, for example, as follows.
That is, inorganic fine particles (preferably gas phase method silica fine particles) and a dispersant are added to water (for example, 10 to 20% by mass of inorganic fine particles in water), and a high-speed rotating wet colloid mill (for example, M Technique). (Cleamix) manufactured by Co., Ltd.), for example, under high speed rotation conditions of 10,000 rpm (preferably 5000 to 20000 rpm), for example, for 20 minutes (preferably 10 to 30 minutes). For example, boric acid), a polyvinyl alcohol (PVA) aqueous solution (for example, PVA having a mass of about 1/3 of the inorganic fine particles) and a nitrogen-containing organic cationic polymer are added, and the water-soluble polyvalent metal is further added. It can be prepared by adding a salt (for example, basic polyaluminum hydroxide) and dispersing under the same rotational conditions as described above.
The water-soluble polyvalent metal salt may be added by in-line mixing immediately before application.
Moreover, a liquid-liquid collision type disperser (for example, an optimizer manufactured by Sugino Machine Co., Ltd.) can also be used for the dispersion.
The obtained coating liquid is in a uniform sol state, and a porous ink-receiving layer having a three-dimensional network structure can be formed by applying the coating liquid onto a support by the following coating method and drying it.

In addition, the preparation of an aqueous dispersion composed of the inorganic fine particles (preferably gas phase method silica) and a dispersant may be performed by preparing an inorganic fine particle aqueous dispersion in advance and adding the aqueous dispersion to the aqueous dispersant solution. Alternatively, the dispersant aqueous solution may be added to the inorganic fine particle aqueous dispersion, or may be mixed at the same time. Further, instead of the inorganic fine particle aqueous dispersion, powdery inorganic fine particles may be added to the aqueous dispersant solution as described above.
After mixing the inorganic fine particles and the dispersant, the mixture is finely divided using a disperser, whereby an aqueous dispersion having an average particle size of 50 to 300 nm can be obtained. Dispersers used for obtaining the aqueous dispersion include various types of conventionally known high-speed rotating dispersers, medium stirring dispersers (ball mill, sand mill, etc.), ultrasonic dispersers, colloid mill dispersers, high pressure dispersers and the like. Although a disperser can be used, a stirrer-type disperser, a colloid mill disperser, or a high-pressure disperser is preferable from the viewpoint that the formed fine particles are efficiently dispersed.

  Moreover, water, an organic solvent, or these mixed solvents can be used as a solvent in each process. Examples of the organic solvent that can be used for this coating include alcohols such as methanol, ethanol, n-propanol, i-propanol, and methoxypropanol, ketones such as acetone and methyl ethyl ketone, tetrahydrofuran, acetonitrile, ethyl acetate, and toluene. It is done.

In addition, a chaotic polymer can be used as the dispersant. Examples of the chaotic polymer include mordant examples described in paragraphs [0138] to [0148] of JP-A-2006-321176. It is also preferable to use a silane coupling agent as the dispersant.
The amount of the dispersant added to the fine particles is preferably 0.1% to 30%, more preferably 1% to 10%.

(Second coating liquid)
The second coating liquid in the present invention contains at least one inorganic fine particle and at least one water-soluble aluminum compound.
The details of the inorganic fine particles in the second coating liquid are as described for the inorganic fine particles in the ink receiving layer. Moreover, there is no restriction | limiting in particular as content rate of the inorganic fine particle in a 2nd coating liquid, However, It is preferable that it is 50-85 mass% with respect to the total solid of a 2nd coating liquid, 55-70 mass%. It is more preferable that

  The water-soluble aluminum compound contained in the second coating liquid in the present invention is as described for the water-soluble aluminum compound in the ink receiving layer. Further, the content of the water-soluble aluminum compound in the second coating solution is not particularly limited, but from the viewpoint of ozone resistance, it is preferably 0.1 to 10% by mass with respect to the inorganic fine particles, More preferably, it is 0.5-8 mass%.

The 2nd coating liquid in this invention can contain a nitrogen-containing organic cationic polymer in the range which does not impair the effect of this invention.
For example, from the viewpoint of forming the nitrogen-containing organic cationic polymer in the formed ink receiving layer so as to be contained in a layer closer to the support than in a layer far from the support in the ink receiving layer, the second It is preferable that the content of the nitrogen-containing organic cationic polymer in the coating solution is less than the content of the nitrogen-containing organic cationic polymer in the first coating solution.
That is, the content ratio of the nitrogen-containing organic cationic polymer [the content in the second coating solution / the content in the first coating solution] needs to be less than 1.0.
Further, the second coating liquid in the present invention may be at least one selected from cationic polyurethanes and cationic polymers having a quaternary ammonium base as the nitrogen-containing organic cationic polymer (hereinafter, referred to as “specific nitrogen-containing organic cationic polymer”). ), The content ratio is preferably 0 to 0.7, more preferably 0 to 0.4, and 0 (that is, the second coating liquid) from the viewpoint of obtaining the effect of the present invention more effectively. Is a form in which the specific nitrogen-containing organic cationic polymer is not included.

  Further, from the viewpoint of obtaining the effect of the present invention more effectively, the content of the specific nitrogen-containing organic cationic polymer in the second coating solution is 0 to 8 with respect to the total solid content of the second coating solution. % By mass is preferable, 0 to 4% by mass is more preferable, and 0% by mass (that is, the form in which the coating liquid B does not include the specific nitrogen-containing organic cationic polymer) is particularly preferable.

The second coating liquid may contain a sulfur compound, but from the viewpoint of keeping the density of the recorded image higher, the content of the sulfur compound in the second coating liquid is set to the value of the first coating liquid. It is preferable to make it less than content of the sulfur type compound in a liquid.
That is, the sulfur compound content ratio [content in the second coating solution / content in the first coating solution] needs to be less than 1.0.
In this case, the content ratio of the sulfur compound [content in the second coating solution / content in the first coating solution] is preferably 0 to 0.6, more preferably 0 to 0.3, 0 (that is, a form in which the second coating solution does not contain a sulfur compound) is particularly preferable.

  Moreover, from the viewpoint of obtaining the effect of the present invention more effectively, the content of the sulfur-based compound in the second coating solution is 0 to 5% by mass with respect to the total solid content of the second coating solution. 0 to 3% by mass is more preferable, and 0% by mass (that is, the form in which the second coating solution does not contain a sulfur compound) is particularly preferable.

Further, the second coating liquid may contain other components such as a water-soluble resin, a dispersant, a crosslinking agent, a water-soluble polyvalent metal salt, a mordant, and a surfactant.
Moreover, in application | coating of a 2nd coating liquid, it is also preferable to apply, after carrying out in-line mixing of the liquid containing the above-mentioned water-soluble polyvalent metal salt (preferably basic polyaluminum chloride).
Details of each component such as a sulfur compound, a water-soluble resin, a mordant, a surfactant, and a water-soluble polyvalent metal salt are the same as those described in the section of <Ink Receptive Layer>, and preferred forms are also the same. is there. The dispersant is as described in the description of the first coating liquid, and the preferable range is also the same.
Further, the second coating solution can be prepared by the same method as the first coating solution described above.

  As with the first coating solution, the second coating solution is preferably acidic, and the pH is preferably 5.0 or less, more preferably 4.5 or less. More preferably, it is 0 or less. This pH can be adjusted by appropriately selecting the type and addition amount of the cationic resin. Moreover, you may adjust by adding an organic or inorganic acid. When the pH of the first liquid B is 5.0 or less, for example, the crosslinking reaction of the water-soluble resin by the crosslinking agent (particularly the boron compound) in the first liquid B can be more sufficiently suppressed.

(Other coating solutions)
Hereinafter, other coating solutions that may be used as necessary will be described.
The other coating liquid preferably contains colloidal silica. By further applying another coating solution containing colloidal silica onto the second coating solution, a colloidal silica layer can be formed as the uppermost layer in the ink receiving layer. Thereby, the glossiness of the formed ink receiving layer can be further improved.
The colloidal silica is as described in the above section <Ink receiving layer>, and the preferred range is also the same.
Other coating liquids can be prepared, for example, by adding colloidal silica to ion-exchanged water, and mixing and stirring.

<Curing process>
In the first embodiment, the coating layer formed in the coating layer forming step is
(1) At the same time as applying at least the first coating liquid and the second coating liquid,
(2) At least during the drying of the coating layer formed by applying the first coating solution and the second coating solution, and before the coating layer exhibits reduced-rate drying,
In any of the cases, there is a step of applying a liquid containing a basic compound and crosslinking and curing the coating layer (hereinafter, this step may be referred to as a “curing step”).

Examples of the method for applying the “liquid containing a basic compound” at the same time as “(1) at least the first coating liquid and the second coating liquid are applied” include the first coating liquid and the second coating liquid. It is preferable that the coating solution (the other coating solution if necessary) and the “liquid containing a basic compound” are simultaneously applied (multilayer coating) in this order from the support side.
Alternatively, after the first coating liquid is applied, the second coating liquid and the “liquid containing a basic compound” are simultaneously applied onto the applied first coating liquid (hereinafter referred to as “simultaneous multilayer coating”). You may say).
The simultaneous coating (simultaneous multilayer coating) can be performed using a known coating device such as an extrusion die coater or a curtain flow coater.

“(2) Basic compound in the middle of drying of the coating layer formed by applying at least the first coating solution and the second coating solution and before the coating layer exhibits reduced-rate drying” The method of applying the “liquid containing” is a method called “Wet-On-Wet method” or “WOW method”. Details of the “Wet-On-Wet method” are described, for example, in paragraph numbers [0016] to [0037] of JP-A-2005-14593.
In the present invention, the first coating liquid and the second coating liquid (and other coating liquids as necessary) are simultaneously applied (simultaneous multi-layer coating) so as to be in this order from the support side. Alternatively, after forming the coating layer by coating one layer at a time, before the coating layer is in the course of drying, and before the coating layer exhibits reduced-rate drying, (i) further “basic compound” (Ii) a method of spraying the “liquid containing a basic compound” by spraying or the like, (iii) the support on which the coating layer is formed in the “liquid containing a basic compound” And a method of immersing in water.

  In the above (i), as a coating method for applying the “liquid containing a basic compound”, for example, curtain flow coater, extrusion die coater, air doctor coater, bread coater, rod coater, knife coater, squeeze coater, reverse A known coating method such as a roll coater or a bar coater can be used. However, it is preferable to use a method in which the coater does not directly contact an already formed coating layer, such as an extrusion die coater, a curtain flow coater, a bar coater or the like.

  In the cross-linking curing step, “before the coating layer comes to show reduced-rate drying” usually means an ink-receiving layer coating solution (in the present invention, the first coating solution and the second coating solution ( Furthermore, it refers to a process for several minutes immediately after the application of other coating liquids)) as necessary, during which the content of the solvent (dispersion medium) in the coated coating layer decreases in proportion to time. The phenomenon of “constant rate drying” is shown. About the time which shows this "constant rate drying", it describes in chemical engineering handbook (pages 707-712, Maruzen Co., Ltd. issue, October 25, 1980), for example.

  As a condition for the above-mentioned “drying until the coating layer exhibits reduced rate drying”, it is generally carried out at 40 to 180 ° C. for 0.5 to 10 minutes (preferably 0.5 to 5 minutes). The drying time naturally varies depending on the coating amount, but usually the above range is appropriate.

(Liquid containing basic compound)
Here, the “liquid containing a basic compound” in the crosslinking curing step will be described.
~ Basic compounds ~
The “liquid containing a basic compound” in the present invention contains at least one basic compound.
Basic compounds include ammonium salts of weak acids, alkali metal salts of weak acids (eg, lithium carbonate, sodium carbonate, potassium carbonate, lithium acetate, sodium acetate, potassium acetate, etc.), alkaline earth metal salts of weak acids (eg, carbonate Magnesium, barium carbonate, magnesium acetate, barium acetate, etc.), hydroxyammonium, primary to tertiary amines (eg, triethylamine, tripropylamine, tributylamine, trihexylamine, dibutylamine, butylamine, etc.), primary to tertiary anilines ( For example, diethylaniline, dibutylaniline, ethylaniline, aniline, etc.), pyridine which may have a substituent (for example, 2-aminopyridine, 3-aminopyridine, 4-aminopyridine, 4- (2-hydroxyethyl) -Aminopyrid Etc.), and the like.

  In addition to the basic compound, other basic substances and / or salts thereof may be used in combination with the basic compound. Examples of other basic substances include ammonia, primary amines such as ethylamine and polyallylamine, secondary amines such as dimethylamine, tertiary amines such as N-ethyl-N-methylbutylamine, and alkali metals. And alkaline earth metal hydroxides.

Among the above, ammonium salts of weak acids are particularly preferable. The weak acid is an inorganic acid or an organic acid described in Chemical Handbook Fundamentals II (Maruzen Co., Ltd.) or the like and having an pKa of 2 or more. Examples of the weak acid ammonium salt include ammonium carbonate, ammonium hydrogen carbonate, ammonium borate, ammonium acetate, and ammonium carbamate. However, it is not limited to these. Among these, ammonium carbonate, ammonium hydrogen carbonate, and ammonium carbamate are preferable, and are effective in that ink bleeding can be reduced without remaining in the layer after drying.
Two or more basic compounds can be used in combination.

  The content of the basic compound (particularly the ammonium salt of a weak acid) in the “liquid containing the basic compound” is 0.5 to 0.5% relative to the total mass (including the solvent) of the “liquid containing the basic compound”. 10 mass% is preferable, More preferably, it is 1-5 mass%. When the content of the basic compound (particularly the ammonium salt of the weak acid) is particularly in the above range, a sufficient degree of curing can be obtained, and the ammonia concentration becomes too high without impairing the working environment.

~ Metal compound ~
The “liquid containing a basic compound” in the present invention preferably contains at least one metal compound.

  As the metal compound contained in the “liquid containing a basic compound”, those that are stable under basicity can be used without limitation, and the above-mentioned water-soluble polyvalent metal salts, metal complex compounds, inorganic oligomers, or inorganic polymers can be used. Any of these may be used. For example, zirconium compounds and compounds listed as inorganic mordants in paragraphs [0100] to [0101] of JP-A-2005-14593 are suitable. Examples of the metal complex compound include metal complexes described in “Chemistry Review No. 32 (1981)” edited by the Chemical Society of Japan, “Coordination Chemistry Review”, Vol. 84, pages 85-277. (1988) and JP-A-2-182701, transition metal complexes containing a transition metal such as ruthenium can be used.

  Among the above, zirconium compounds and zinc compounds are preferable, and zirconium compounds are particularly preferable. Examples of the zirconium compound include zirconium carbonate / ammonium, zirconium nitrate / ammonium, zirconium carbonate / potassium, zirconium citrate / ammonium citrate, zirconyl stearate, zirconyl octylate, zirconyl nitrate, zirconium oxychloride, and zirconium zirconium hydroxychloride. Particularly preferred is zirconium ammonium carbonate. Moreover, two or more metal compounds (preferably containing a zirconium compound) may be used in combination in the “liquid containing a basic compound”.

  As content in the "liquid containing a basic compound" of the said metal compound (especially zirconium compound), it is 0.05-5 mass% with respect to the total mass (a solvent is included) of "the liquid containing a basic compound". Is more preferable, and 0.1 to 2% by mass is more preferable. By setting the content of the metal compound (especially zirconium compound) in the above range, the coating layer can be sufficiently hardened, and the mordant ability is lowered, so that a sufficient printing density cannot be obtained, or beading is not achieved. It does not occur, and the working environment is not deteriorated due to the concentration of a basic compound such as ammonia becoming too high. Two or more metal compounds can be used in combination, and when other mordant components to be described later are used in combination with a metal compound other than the metal compound, the total amount is within the above range and does not impair the effects of the present invention. It can be contained in a range.

From the viewpoint of image density and ozone resistance, the “liquid containing a basic compound” preferably contains the aforementioned magnesium salt as a metal compound. As the magnesium salt, magnesium chloride is particularly preferable.
In this case, the addition amount of the magnesium salt is preferably 0.1 to 1% by mass and more preferably 0.15 to 0.5% by mass with respect to the total mass of the “liquid containing a basic compound”.

The “liquid containing a basic compound” can contain a crosslinking agent and other mordant components as necessary.
The “liquid containing a basic compound” can promote dura mater when used as an alkaline solution, and is preferably adjusted to pH 7.1 or higher, more preferably pH 8.0 or higher, and particularly preferably pH 9.0. That's it. When the pH is 7.1 or more, the crosslinking reaction of the water-soluble resin that may be contained in the first coating liquid and / or the second coating liquid can be further promoted, and bronzing and cracking of the ink receiving layer can be performed. Can be suppressed more effectively.

  The “liquid containing a basic compound” includes, for example, ion-exchanged water, a metal compound (eg, zirconia compound; eg, 1 to 5%) and a basic compound (eg, ammonium carbonate; eg, 1 to 5%), It can be prepared by adding para-toluenesulfonic acid (for example, 0.5 to 3%) as necessary and stirring sufficiently. In addition, all "%" of each composition means solid content mass%.

  In addition, water, an organic solvent, or a mixed solvent thereof can be used as a solvent used for preparing the “liquid containing a basic compound”. Examples of the organic solvent that can be used for coating include alcohols such as methanol, ethanol, n-propanol, i-propanol, and methoxypropanol, ketones such as acetone and methyl ethyl ketone, tetrahydrofuran, acetonitrile, ethyl acetate, and toluene. .

<Cooling process and drying process>
In the second aspect, the coating layer formed in the coating layer forming step is applied to the lower one of the temperature of the first coating solution at the time of coating and the temperature of the second coating solution at the time of coating. A step of cooling to lower by 5 ° C. or more (hereinafter also referred to as “cooling step”), a step of drying the cooled coating layer to form an ink receiving layer (hereinafter also referred to as “drying step”), Have

As a method of cooling the coating layer in the cooling step, a method of cooling the support on which the coating layer is formed in a cooling zone maintained at 0 to 10 ° C. for 5 to 30 seconds is preferable.
In a cooling process, it is preferable to cool so that it may fall 0-10 degreeC, and it is more preferable to cool so that it may fall 0-5 degreeC or more.
Here, the temperature of the coating layer is measured by measuring the temperature of the film surface.

<Other processes>
In the first embodiment and the second embodiment, after forming the ink receiving layer on the support, the ink receiving layer is made of, for example, a super calender, a gloss calendar, or the like, and is calendered between the roll nips under heat and pressure. By performing the treatment, it is possible to improve surface smoothness, glossiness, transparency and coating strength. However, the calendar process may cause a decrease in the porosity (that is, the ink absorptivity may be decreased), so it is necessary to set conditions under which the decrease in the porosity is small.

As roll temperature in the case of performing a calendar process, 30-150 degreeC is preferable and 40-100 degreeC is more preferable.
Moreover, as a linear pressure between rolls at the time of a calendar process, 50-400 kg / cm is preferable and 100-200 kg / cm is more preferable.

≪Inkjet recording method≫
The inkjet recording medium manufactured by the inkjet recording medium manufacturing method of the present invention can be preferably applied to the inkjet recording method described in detail below.
The ink jet recording method of the present invention is an ink containing a water-soluble dye represented by the following general formula (M) or general formula (Bk) on the ink jet recording medium manufactured by the method of manufacturing an ink jet recording medium of the present invention. It includes a step of applying at least one of the above by an ink jet method.
By combining the ink jet recording medium produced by the method for producing an ink jet recording medium of the present invention and an ink containing a water-based dye having a specific structure, the effect of suppressing blur (bleeding over time) of the recorded image, high image density, The ozone resistance effect can be realized at a better level. The ink receiving layer of the ink jet recording medium in the present invention contains a large amount of a nitrogen-containing organic cationic polymer in a layer close to the support. Therefore, for example, when the water-soluble dye represented by the general formula (M) or the general formula (Bk) penetrates to the layer close to the support of the ink receiving layer, the effect of suppressing the occurrence of bleeding is more effectively achieved. It is considered a thing.
In the present invention, the water-soluble dye means a dye that dissolves 1% by mass or more in water at 20 ° C.

In the general formula (M), A ₃₁ represents a 5-membered heterocyclic group.
B ₃₁ and _{B 32} are each ₌ CR 31 -, - or represents _{CR 32} =, or either one nitrogen atom and the other = _{CR 31} - represents a or _{-CR 32} =. R ₃₅ and R ₃₆ are each independently a hydrogen atom, aliphatic group, aromatic group, heterocyclic group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, heterocyclic oxycarbonyl group, carbamoyl group, alkyl or arylsulfonyl group Represents a heterocyclic sulfonyl group or a sulfamoyl group, and each group may further have a substituent.
G ₃ , R ₃₁ and R ₃₂ are each independently a hydrogen atom, a halogen atom, an aliphatic group, an aromatic group, a heterocyclic group, a cyano group, a carboxyl group, a carbamoyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, Heterocyclic oxycarbonyl group, acyl group, hydroxy group, alkoxy group, aryloxy group, heterocyclic oxy group, silyloxy group, acyloxy group, carbamoyloxy group, alkoxycarbonyloxy group, aryloxycarbonyloxy group, amino group (arylamino) Group, including heterocyclic amino group), acylamino group, ureido group, sulfamoylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, alkyl or arylsulfonylamino group, heterocyclic sulfonylamino group, nitro group, alkyl And Represents an alkylthio group, an alkyl and arylsulfonyl group, a heterocyclic sulfonyl group, an alkyl and arylsulfinyl group, a heterocyclic sulfinyl group, a sulfamoyl group, a sulfonic acid group, or a heterocyclic thio group, and each group may be further substituted. .
R ₃₁ and R ₃₅ , or R ₃₅ and R ₃₆ may combine to form a 5- to 6-membered ring.
Note that at least one of A ₃₁ , R ₃₁ , R ₃₂ , R ₃₅ , R ₃₆ and G ₃ has a sulfonic acid group, and has Li ⁺ or a quaternary ammonium ion as a counter ion.

Specific examples of the water-soluble dye represented by the general formula (M) include International Patent Publication No. 2002/83795 (pages 35-55), 2002-83661 (pages 27-42), and JP-A No. 2004-149560. (Paragraph numbers [0046] to [0059]) and 2004-149561 (paragraph numbers [0047] to [0060]), the water-soluble group is only a sulfonic acid group, and the counter ion is Examples include Li ⁺ ions or quaternary ammonium ions. Specific examples of particularly preferred water-soluble dyes represented by the general formula (M) are shown below in terms of the structure of a free acid, but they are preferably used as salts.

  In the present invention, the content of the water-soluble dye (heterocyclic azo dye) represented by formula (M) in the magenta ink is preferably 0.2 to 20% by mass, more preferably 0.5 to 15% by mass. preferable.

In general formula (Bk), A ₁ , A ₂ and A ₃ each independently represents an optionally substituted aromatic group or an optionally substituted heterocyclic group. A ₁ and A ₃ are monovalent groups, and A ₂ is a divalent group. At least one of A ₁ , A ₂ and A ₃ is preferably a heterocyclic group.

  Examples of the water-soluble dye represented by the general formula (Bk) in the present invention include water-soluble dyes described in paragraph numbers [0041] to [0059] of JP-A-2007-70573. The range is the same.

  In the present invention, the content of the compound represented by the general formula (Bk) in the ink is preferably 0.2 to 20% by mass, and more preferably 0.5 to 15% by mass.

In addition, it is preferable that the ink containing the water-soluble dye represented by the general formula (Bk) in the present invention further contains a water-soluble short wave dye.
Specific examples of the water-soluble short wave dye include water-based dyes described in paragraph numbers [0061] to [0072] of JP-A-2007-70573, and the same applies to preferred embodiments.

  The ink in the present invention contains at least one water-soluble dye represented by the general formula (M) and the general formula (Bk) and an aqueous medium, and if necessary, other additives may be added to the effect of the present invention. Can be added within a range that does not harm. Other additives include, for example, boron compounds, anti-drying agents (wetting agents), anti-fading agents, emulsion stabilizers, penetration enhancers, ultraviolet absorbers, antiseptics, anti-fungal agents, pH adjusters, and surface tension adjusters. Known additives such as an agent, an antifoaming agent, a viscosity modifier, a dispersant, a dispersion stabilizer, a rust inhibitor, and a chelating agent can be used.

  As the aqueous medium, a mixture containing water as a main component and optionally adding a water-miscible organic solvent can be used. Examples of the water-miscible organic solvent include alcohols (eg, methanol, ethanol, propanol, isopropanol, butanol, isobutanol, sec-butanol, t-butanol, pentanol, hexanol, cyclohexanol, benzyl alcohol), polyvalent Alcohols (eg, 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, 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 (for example, ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, morpholine, N-ethylmorpholine, ethylenediamine, diethylenetriamine) , Triethylenetetramine, polyethyleneimine, tetramethylpropylenediamine) and other polar solvents (eg, formamide, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, sulfolane, 2-pyrrolidone, N-methyl- 2-pyrrolidone, N-vinyl-2-pyrrolidone, 2-oxazolidone, 1,3-dimethyl-2-imidazolidinone, acetonitrile, acetone). In addition, the said water miscible organic solvent may use 2 or more types together.

  The anti-drying agent is preferably used for the purpose of preventing clogging due to drying of ink at an ink ejection port of a nozzle used in an ink jet recording system.

  The anti-drying agent is preferably a water-soluble organic solvent having a vapor pressure lower than that of water. Specific examples include ethylene glycol, propylene glycol, diethylene glycol, polyethylene glycol, thiodiglycol, dithiodiglycol, 2-methyl-1,3-propanediol, 1,2,6-hexanetriol, acetylene glycol derivatives, glycerin. Polyhydric alcohols typified by trimethylolpropane, etc., lower alkyl ethers of polyhydric alcohols such as ethylene glycol monomethyl (or ethyl) ether, diethylene glycol monomethyl (or ethyl) ether, triethylene glycol monoethyl (or butyl) ether , Heterocyclic compounds such as 2-pyrrolidone, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, N-ethylmorpholine, sulfolane, dimethyl sulfoxide, 3 Sulfur-containing compounds such as sulfolane, diacetone alcohol, polyfunctional compounds such as diethanolamine, and urea derivatives. Of these, polyhydric alcohols such as glycerin and diethylene glycol are more preferred. Moreover, said anti-drying agent may be used independently and 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.

  The penetration accelerator is preferably used for the purpose of allowing the ink to penetrate better into paper. Examples of the penetration enhancer include alcohols such as ethanol, isopropanol, butanol, di (tri) ethylene glycol monobutyl ether, 1,2-hexanediol, sodium lauryl sulfate, sodium oleate, and nonionic surfactants. it can. If these are contained in the ink in an amount of 5 to 30% by mass, they usually have a sufficient effect, and it is preferable to use them in a range of addition amounts that do not cause printing bleeding and paper loss (print through).

  The ultraviolet absorber is used for the purpose of improving image storage stability. Examples of the ultraviolet absorber 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. The compounds described in No. 24239, compounds that emit fluorescence by absorbing ultraviolet rays typified by stilbene-based compounds 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 anti-fading agent, various organic and metal complex anti-fading agents can be used. Organic anti-fading agents include hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indanes, chromans, alkoxyanilines, thioethers, thioureas (thioethers and thioureas) Examples include JP-A-2002-36717, and examples of thioethers are described in JP-A-2002-86904), heterocycles, etc., and metal complexes include nickel complexes and zinc complexes. More specifically, Research Disclosure No. No. 17643, Nos. VII to I, J; 15162, ibid. 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 No. 15162 and the compounds included in the general formulas and compound examples of the representative compounds described in pages 127 to 137 of JP-A-62-215272 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 the ink in an amount of 0.02 to 1.00% by mass.

  The neutralizer (organic base, inorganic alkali) can be used as the pH adjuster. For the purpose of improving the storage stability of the ink, the pH adjuster is preferably added so that the 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, cationic and anionic surfactants. The surface tension of the ink according to the present invention is preferably 25 to 70 mN / m. Furthermore, 25-60 mN / m is preferable. The viscosity of the ink according to the present invention is preferably 30 mPa · s or less. Furthermore, it is more preferable to adjust to 20 mPa · s or less.

  Examples of surfactants include fatty acid salts, alkyl sulfate esters, alkyl benzene sulfonates, alkyl naphthalene sulfonates, dialkyl sulfosuccinates, alkyl phosphate ester salts, naphthalene sulfonate formalin condensates, polyoxyethylene alkyl sulfates. Anionic surfactants such as ester salts, polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylamine, glycerin fatty acid ester Nonionic surfactants such as oxyethyleneoxypropylene block copolymers are preferred. Further, SURFYNOLS (Air Products & Chemicals), which is an acetylene-based polyoxyethylene oxide surfactant, is also preferably used. Also preferred are amine oxide types such as N, N-dimethyl-N-alkylamine oxide and betaine type amphoteric surfactants containing quaternary ammonium salts such as N, N-dimethyl-N-lauryl-carbomethylammonium. . Further, JP-A-59-157,636, pages (37) to (38), Research Disclosure No. The surfactants described in 308119 (1989) can also be used.

  As the antifoaming agent, fluorine-based, silicone-based compounds, chelating agents represented by EDTA, and the like can be used as necessary.

  The method for preparing the ink in the present invention is not particularly limited. For example, JP-A Nos. 5-148436, 5-295212, 7-97541, 7-82515, 7-118584, and JP-A-2004. Details are described in each method of No. 331871 and can also be applied to the preparation of ink in the present invention.

The ink in the present invention can be used as an ink set including at least a yellow ink containing a yellow dye and a cyan ink containing a cyan dye.
Although there is no restriction | limiting in particular as said yellow dye, For example, the yellow dye as described in Paragraph [0025]-[0040] etc. of Unexamined-Japanese-Patent No. 2007-70573 can be used.
The cyan dye is not particularly limited. For example, cyan dyes described in paragraphs [0083] to [0090] of JP-A-2007-70573 can be used.

  There is no particular limitation on the ink jet system for recording an image on the ink jet recording medium of the present invention, and a known system, for example, a charge control system for ejecting ink using electrostatic attraction, and the vibration pressure of the piezo element are controlled. Drop-on-demand method (pressure pulse method) to be used, an acoustic signal is converted into an acoustic beam, the ink is irradiated, an acoustic ink jet method that ejects ink using radiation pressure, and ink is heated to form bubbles, A thermal ink jet method using the generated pressure can be used. The ink jet recording method includes a method of ejecting a large number of low-density inks called photo inks in a small volume, a method of improving image quality using a plurality of inks having substantially the same hue and different concentrations, and colorless and transparent. A method using ink is included.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. In the examples, “parts” and “%” represent “parts by mass” and “% by mass” unless otherwise specified.

[Example 1]
≪Preparation of inkjet recording medium≫
<Production of support>
Wood pulp consisting of 100 parts of LBKP is beaten to 300 ml Canadian freeness with a double disc refiner, 0.5 parts of epoxidized behenamide, 1.0 part of anionic polyacrylamide, 0.1 part of polyamide polyamine epichlorohydrin, 0.5 part of cationic polyacrylamide All the parts were added at an absolutely dry mass ratio to the pulp, and weighed with a long net paper machine to make a base paper of 170 g / m ² .

In order to adjust the surface size of the base paper, 0.04% of a fluorescent whitening agent (“Whiteex BB” manufactured by Sumitomo Chemical Co., Ltd.) was added to a 4% aqueous solution of polyvinyl alcohol, and this was converted to 0 in terms of absolute dry weight. The base paper was impregnated so as to be 0.5 g / m ² , dried, and then subjected to a calender treatment to obtain a base paper adjusted to a density of 1.05.

After the corona discharge treatment was performed on the wire surface (back surface) side of the obtained base paper, high-density polyethylene was coated to a thickness of 19 μm using a melt extruder to form a resin layer composed of a mat surface. (Hereinafter, this resin layer surface is referred to as “back surface”). The back side resin layer is further subjected to a corona discharge treatment, and thereafter, as an antistatic agent, aluminum oxide (“Alumina Sol 100” manufactured by Nissan Chemical Industries, Ltd.) and silicon dioxide (“Snow manufactured by Nissan Chemical Industries, Ltd.”) are used. Tex O ") the mass ratio of 1: a dispersion dispersed in water at 2, dry weight was applied as a 0.2 g / m ^2.

  Furthermore, after the corona discharge treatment is applied to the felt surface (surface) side where the resin layer is not provided, anatase-type titanium dioxide 10%, a trace amount of ultramarine blue, and a fluorescent whitening agent 0.01% (vs. polyethylene) Low-density polyethylene containing MFR (melt flow rate) 3.8 is melt-extruded to a thickness of 29 μm using a melt extruder, and a high-gloss thermoplastic resin layer is formed on the surface side of the base paper. (Hereinafter, this highly glossy surface is referred to as “front side”), and used as a support for this example.

<Preparation of second coating liquid (for upper layer)>
(1) Gas phase method silica fine particles, (2) ion-exchanged water, (3) “Charol DC-902P”, and (4) “ZA-30” shown in the following composition are mixed, After dispersion using a collision type disperser (Ultimizer, manufactured by Sugino Machine Co.), the obtained dispersion was heated to 45 ° C. and held for 20 hours. Thereafter, (5) polyvinyl alcohol solution was added to the dispersion at 30 ° C. to prepare a second coating solution (for the upper layer).
The mass ratio between the silica fine particles and the water-soluble resin (PB ratio = (1) :( 5)) is 4.0: 1, and the pH of the second coating liquid (for the upper layer) is 3.4 and acidic. showed that.

-Composition of second coating liquid (for upper layer)-
(1) Gas phase method silica fine particles (inorganic fine particles) 8.9 parts (AEROSIL300SF75, manufactured by Nippon Aerosil Co., Ltd.)
(2) Ion-exchanged water ... 54.4 parts (3) "Charol DC-902P" (51.5% aqueous solution) ... 0.78 parts (dispersant, nitrogen-containing organic cationic polymer, Daiichi Kogyo Seiyaku) (Made by Co., Ltd.)
(4) “ZA-30”: 0.48 part (Daiichi Rare Element Chemical Co., Ltd., zirconyl acetate)
(5) Polyvinyl alcohol (water-soluble resin) solution ... 31.2 parts-Composition of solution-
・ PVA235 (saponification degree 88%, polymerization degree 3500, manufactured by Kuraray Co., Ltd.)
・ ・ ・ 2.2 parts ・ Ion-exchanged water ・ ・ ・ 28.2 parts ・ Diethylene glycol monobutyl ether (Buticenol 20P) ・ ・ ・ 0.7 parts (Kyowa Hakko Chemical Co., Ltd.)
・ Emulgen 109P (surfactant, manufactured by Kao Corporation) 0.1 part

<Preparation of first coating liquid (for lower layer)>
(1) Gas phase method silica fine particles, (2) ion-exchanged water, (3) “Charol DC-902P”, (4) “ZA-30”, (5) “30” shown in the following composition % Methionine sulfoxide ”was mixed and dispersed using a liquid-liquid collision type disperser (Ultimizer, manufactured by Sugino Machine Co., Ltd.), and then the dispersion was heated to 45 ° C. and held for 20 hours. Thereafter, (6) boric acid, (7) polyvinyl alcohol solution, and (8) “Superflex 650” were added to the dispersion at 30 ° C. to prepare a first coating liquid (for the lower layer).
The mass ratio between the silica fine particles and the water-soluble resin (PB ratio = (1) :( 7)) is 4.0: 1, and the pH of the first coating liquid (for the lower layer) is 3.8 and acidic. showed that.

-Composition of first coating liquid (for lower layer)-
(1) Gas phase method silica fine particles (inorganic fine particles) 8.9 parts (AEROSIL300SF75, manufactured by Nippon Aerosil Co., Ltd.)
(2) Ion-exchanged water: 48.5 parts (3) “Charol DC-902P” (51.5% aqueous solution): 0.78 parts (dispersant, nitrogen-containing organic cationic polymer, Daiichi Kogyo Seiyaku) (Made by Co., Ltd.)
(4) “ZA-30”: 0.48 part (Daiichi Rare Element Chemical Co., Ltd., zirconyl acetate)
(5) 30% methionine sulfoxide (sulfur compound) ... 1.76 parts (6) boric acid (crosslinking agent) ... 0.4 parts (7) polyvinyl alcohol (water-soluble resin) solution ... 31.2 parts-Composition of the solution-
・ PVA235 (saponification degree 88%, polymerization degree 3500, manufactured by Kuraray Co., Ltd.)
・ ・ ・ 2.2 parts ・ Ion-exchanged water ・ ・ ・ 28.2 parts ・ Diethylene glycol monobutyl ether (Buticenol 20P) ・ ・ ・ 0.7 parts (Kyowa Hakko Chemical Co., Ltd.)
・ Emulgen 109P (surfactant, manufactured by Kao Corporation) ... 0.1 part (8) "Superflex 650" ... 3.1 parts (Nitrogen-containing organic cationic polymer emulsion, Daiichi Kogyo Seiyaku Co., Ltd. ) Made)

<Formation of ink receiving layer>
After the front surface of the support is subjected to corona discharge treatment, the first coating liquid (for the lower layer) and the second coating liquid (for the upper layer) are applied to the front surface as follows. The coating solution temperature was set to 38 ° C. with a coater, and simultaneous coating was applied to form a coating layer.
Specifically, in the simultaneous multilayer coating, coating the first coating solution (for lower layer) at 105.1 g / ^{m 2,} the lower layer after the following in-line solution were in-line mixing at a rate of 3.3 g / ^{m 2} and, a second coating solution (for upper layer) at 106 g / ^{m 2,} the following line liquid was coated on the upper layer after line mixing at a rate of 13.2 g / ^{m 2} (layer structure, the second coating liquid ( (For upper layer) / first coating liquid (for lower layer) / support).

~ Composition of inline liquid ~
(1) Alphain 83 (manufactured by Daimei Chemical Co., Ltd.) 2.0 parts (2) Ion-exchanged water 7.8 parts (3) Himax SC-507 (Dimethylamine / Epichlorohydrin) 0.2 parts

The coating layer formed by the simultaneous multilayer coating was dried with a hot air drier at 80 ° C. (wind speed 3 to 8 m / sec) until the solid content concentration of the coating layer became 24%. This coating layer exhibited a constant rate of drying during this period. Immediately after that, it was immersed in a solution containing a basic compound having the following composition for 3 seconds to deposit 13 g / m ² on the coating layer, and further dried at 72 ° C. for 10 minutes (drying step). An ink receiving layer was formed.

~ Composition of liquid containing basic compound ~
(1) Boric acid ... 1.3 parts (2) Ammonium carbonate (1st grade: manufactured by Kanto Chemical Co., Ltd.) ... 5.0 parts (3) Zircozol AC-7 ... 2.5 parts ( Zirconyl ammonium carbonate (Daiichi Rare Element Chemical Co., Ltd.)
(4) Ion-exchanged water ... 85.2 parts (5) Polyoxyethylene lauryl ether (surfactant) ... 6.0 parts ("Emulgen 109P" (10% aqueous solution) manufactured by Kao Corporation, HLB Value 13.6)

  As described above, the ink jet recording medium of the present invention in which the ink receiving layer having a dry film thickness of 35 μm was provided on the support was obtained.

[Example 2]
In Example 1, polyvinyl alcohol (water-soluble resin) solution used for the preparation of the first coating solution and the second coating solution was replaced with JM33 (saponification degree: 93.5 to 94.5%, polymerization degree instead of PVA235). An ink jet recording medium was obtained in the same manner as in Example 1 except that it was prepared using 3300, manufactured by Nippon Vinegar Poval Co., Ltd.

Example 3
In the ink-receiving layer formation in Example 1, the same method as in Example 1 except that the in-line liquid mixed in-line with the second coating liquid (for the upper layer) was changed to a speed of 6.6 g / m ^2. A recording medium was obtained.

Example 4
An ink jet recording medium was obtained in the same manner as in Example 1, except that the coating liquid temperature of the first coating liquid and the second coating liquid was changed to 42 ° C. instead of 38 ° C.

[Comparative Example 1]
In the formation of the ink receiving layer in Example 1, instead of the first coating liquid and the second coating liquid, the coating liquid is changed to a coating liquid having the following composition, the coating liquid is 212 ml / m ² , and the in-line liquid is 6 An ink jet recording medium was obtained in the same manner as in Example 1 except that coating was performed after in-line mixing at a speed of 0.6 ml / m ² .
~ Composition of coating liquid ~
(1) Gas phase method silica fine particles (inorganic fine particles) 8.9 parts (AEROSIL300SF75, manufactured by Nippon Aerosil Co., Ltd.)
(2) Ion-exchanged water: 53.3 parts (3) “Charol DC-902P” (51.5% aqueous solution): 0.78 parts (dispersant, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
(4) “ZA-30”: 0.48 part (made by Daiichi Rare Element Chemical Industries, Ltd., zirconium acetate)
(5) Polyvinyl alcohol (water-soluble resin) solution ... 31.2 parts-Composition of solution-
・ PVA235 (saponification degree 88%, polymerization degree 3500, manufactured by Kuraray Co., Ltd.)
・ ・ ・ 2.2 parts ・ Ion-exchanged water ・ ・ ・ 28.2 parts ・ Diethylene glycol monobutyl ether (Buticenol 20P) ・ ・ ・ 0.7 parts (Kyowa Hakko Chemical Co., Ltd.)
・ Emulgen 109P (surfactant, manufactured by Kao Corporation) ... 0.1 part (6) "Superflex 650" ... 1.1 parts (Nitrogen-containing organic cationic polymer emulsion, Daiichi Kogyo Seiyaku Co., Ltd.) ) Made)

[Comparative Example 2]
Ink jet recording medium as in Example 1, except that the temperature of the coating liquid of the first coating liquid and the second coating liquid was changed to 50 ° C. instead of 38 ° C. in the formation of the ink receiving layer in Example 1. Got.

[Comparative Example 3]
Inkjet recording medium as in Example 1, except that the temperature of the first and second coating liquids was changed to 30 ° C. instead of 38 ° C. in forming the ink receiving layer in Example 1. Got.

[Comparative Example 4]
In Example 1, 3.1 parts of “Superflex 650” was further added to the second coating solution, and “Superflex 650” was not added to the first coating solution. Thus, an ink jet recording medium was obtained.

[Comparative Example 5]
In Example 1, the in-line liquid mixed in-line with the second coating liquid was changed to a speed of 3.3 ml / m ² , and the in-line liquid mixed in-line with the first coating liquid was changed to a speed of 13.2 ml / m ² . An ink jet recording medium was obtained in the same manner as in Example 1 except for the change.

[Comparative Example 6]
In Example 1, 1.55 parts of “Superflex 650” was further added to the second coating solution, and the amount of “Superflex 650” added to the first coating solution was not mixed. Was changed to 1.55 parts, and an ink jet recording medium was obtained in the same manner as in Example 1 except that the in-line liquid was changed to 13.2 ml / m ² .

[Comparative Example 7]
In Example 1, the addition amount of “Charol DC-902P” of the second coating solution was changed to 2.3 parts instead of 0.78 part, and the addition amount of “Superflex 650” of the first coating solution The ink jet recording medium was obtained in the same manner as in Example 1 except that 3.1 parts was changed to 0 parts.

≪Preparation of ink≫
After adding deionized water to the following components to make 1 liter, the mixture was stirred for 1 hour while being heated at 30 to 40 ° C. Thereafter, the pH was adjusted to 9 with KOH 10 mol / L, and filtration under reduced pressure was performed using a microfilter having an average pore size of 0.25 μm to prepare an ink liquid for light magenta.

-Magenta dye (compound M-1) represented by the following structural formula 7.5 g / L
・ Diethylene glycol 50g / L
・ Urea 10g / L
・ Glycerin 200g / L
・ Triethylene glycol monobutyl ether 120g / L
・ Triethanolamine 6.9g / L
・ Benzotriazole 0.08g / L
・ 2-Pyrrolidone 20g / L
・ Surfinol 465
(Surfactant manufactured by Air Products Japan) 10.5g / L
・ PROXEL XL-2 (bactericidal agent: manufactured by ICI Japan) 3.5g / L

  Further, magenta ink, light cyan ink, cyan ink, yellow ink, and black ink were prepared by changing the dye species and additives, and ink set 101 having the concentrations shown in Table 1 was prepared.

≪Evaluation≫
The ink jet recording medium obtained above was evaluated using the ink set 101 described below. The evaluation results are shown in Table 2.

<Ozone resistance evaluation method>
Instead of a genuine ink set, an ink jet printer (“PM-A820” manufactured by Epson Corporation) loaded with the ink set 101 was used to print yellow, cyan, and magenta solid images on each recording medium. The sample was stored for 80 hours in an atmosphere of 23 ° C., 60% RH, and ozone concentration of 10 ppm. The residual ratios of yellow density, cyan density and magenta density before and after storage were calculated, and the ozone resistance was evaluated according to the following criteria for the residual ratio of the color having the smallest residual ratio.
~Judgment criteria~
◎: 75% or more ○: 70% or more and less than 75% △: 60% or more and less than 70% ×: less than 60%

<Measurement of black density>
Using the inkjet printer PM-A820 loaded with the ink set 101, solid black printing was performed, and the resulting black portion density was measured with a reflection densitometer (Xrite 938, manufactured by Xrite).

<Smear>
Instead of the genuine ink set, an ink jet printer (trade name: MP-950, manufactured by Canon Inc.) loaded with the ink set 101 is used to form a magenta ink grid pattern on each ink jet recording sheet. (Line width 0.28 nm) was printed and stored for 7 days in a constant temperature and humidity chamber at 23 ° C. and a relative humidity of 90%.
~Judgment criteria~
○: No blur was observed.
(Triangle | delta): Although blur was observed, there was no problem practically.
X: Smudge was observed and there was a problem in practical use.

<Confirmation of distribution of nitrogen-containing organic cationic polymer>
The cross section of the obtained recording medium was cut out by a microtome, and mapping analysis of Si element and N element was performed using SEM-EDX (Hitachi S-2150 combined with EDX apparatus). The presence position of the ink receiving layer was confirmed from the Si element mapping image, and observed side by side with the N element mapping image.
~Judgment criteria~
○: N element in the lower layer in the ink receiving layer> N element in the upper layer ×: N element in the lower layer in the ink receiving layer ≦ N element in the upper layer

<Confirmation of water-soluble aluminum compound distribution>
The cross section of the obtained recording medium was cut out by a microtome, and mapping analysis of Si element and Al element was performed using SEM-EDX (Hitachi S-2150 combined with EDX apparatus). The presence position of the ink receiving layer was confirmed from the Si element mapping image, and observed side by side with the Al element mapping image.
~Judgment criteria~
○: lower Al element in the ink receiving layer <upper Al element ×: lower Al element in the ink receiving layer ≧ upper Al element

As shown in Table 2, the inkjet recording media produced in Examples 1 to 4 of the present invention have a good surface shape, suppressed bleeding of recorded images, high image density, and ozone resistance. It was also excellent.
On the other hand, in Comparative Examples 2 and 3 in which the coating solution temperature was 50 ° C. and 30 ° C., the surface condition deteriorated.
Further, Comparative Example 1 formed from a single layer containing a nitrogen-containing organic cation polymer and a water-soluble aluminum compound, and the content ratio of the nitrogen-containing organic cation polymer [content in the upper layer in the ink receiving layer / in the ink receiving layer In Comparative Examples 4, 6, and 7 in which the content in the lower layer] was 1.0 or more, the image density was lowered and the ozone resistance was deteriorated.
Further, in Comparative Example 5 in which the content ratio of the water-soluble aluminum compound [content in the lower layer in the ink receiving layer / content in the upper layer in the ink receiving layer] is 1.0 or more, the surface condition deteriorates. Ozone resistance and bleeding were also worsened.

Claims (2)

On the support, at least a first coating solution containing inorganic fine particles and a nitrogen-containing organic cationic polymer and a second coating solution containing inorganic fine particles and a water-soluble aluminum compound are sequentially laminated from the support side. As a result, an ink receiving layer having a higher content of the nitrogen-containing organic cationic polymer and a lower content of the water-soluble aluminum compound in a layer closer to the support than a layer far from the support is formed. In addition,
A method for producing an ink jet recording medium, comprising at least a step of applying multiple layers of the first coating liquid and the second coating liquid at a coating liquid temperature of 35 ° C. or higher and 45 ° C. or lower.   2. The method for producing an ink jet recording medium according to claim 1, wherein the nitrogen-containing organic cationic polymer is at least one selected from a cationic polyurethane and a cationic polymer having a quaternary ammonium base.