JP4491396B2 - Inkjet recording medium - Google Patents

Description

  The present invention relates to an inkjet recording medium.

  In recent years, with the rapid development of the information technology (IT) industry, various information processing systems have been developed, and a recording method and a recording apparatus suitable for each information processing system have been developed and put into practical use. Among such recording methods, the inkjet recording method is advantageous in that it can be recorded on various recording materials, the hardware (device) is relatively inexpensive, is compact, and is excellent in low noise. It has been widely used not only in offices but also in so-called home use.

In addition, with the recent increase in resolution of inkjet printers, it is also possible to obtain so-called photographic-like high-quality recorded materials, and along with the further development of hardware (device), various recording sheets for inkjet recording are also available. Improvements have been made.
The characteristics required for a recording sheet for ink jet recording are generally (1) fast drying (fast ink absorption speed), and (2) proper and uniform ink dot diameter (bleeding). (3) Good graininess, (4) High roundness of dots, (5) High color density, (6) High saturation (no dullness) ), (7) The light resistance and water resistance of the print portion are good, (8) The whiteness of the recording sheet is high, (9) The recording sheet has good storage stability (yellowing coloration during long-term storage) (10) hard to deform, good dimensional stability (curl is sufficiently small), (11) good running performance of hardware, Etc. Furthermore, in the use of photo glossy paper used for the purpose of obtaining so-called photographic-like high-quality recorded matter, in addition to the above characteristics, glossiness, surface smoothness, texture of photographic paper similar to silver salt photography, etc. Required.

  In recent years, an ink jet recording medium having a porous structure in an ink receiving layer has been developed and put into practical use for the purpose of improving the various characteristics described above. Such an ink jet recording medium has a porous structure, so that it has excellent ink receptivity (fast drying property) and high glossiness.

In order to achieve a high image density in the inkjet recording medium, it is known that it is effective to make more of a cationic substance serving as a mordant in a part away from the support (for example, patents). Reference 1).
JP 2002-160442 A

  However, in an ink jet recording medium in which at least two ink receiving layers are formed, when a large amount of a cationic substance is present in the uppermost layer, there is a problem that cyan dye is deposited on the uppermost layer surface and bronzing occurs. . This tendency is particularly remarkable in a highly polar cationic substance such as basic polyaluminum hydroxide.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an ink jet recording medium in which the occurrence of bronzing is suppressed in an ink jet recording medium in which at least two ink receiving layers are formed. .

Means of the present invention for solving the above-mentioned problems are as follows.
<1> on a support, an ink jet recording medium comprising an ink receiving layer containing a fumed silica and parent aqueous binder to form at least two layers, the ink-receiving top layer of the ink receiving layer An ink jet recording medium characterized in that there is an ink receiving layer having a higher mass ratio of basic polyaluminum hydroxide to vapor-phase-process silica than the layer, and the uppermost layer contains a water-soluble zirconyl compound .
<2> The mass ratio of basic polyaluminum hydroxide to vapor phase silica in any one of the ink receiving layers other than the uppermost layer is a mass ratio of basic polyaluminum hydroxide to vapor phase silica in the uppermost layer. The inkjet recording medium according to <1>, wherein the ratio is 90% or less .

<3> The inkjet recording medium according to the prior primary particle diameter of crisis phase silica is characterized in that it is 1nm or more 30nm or less <1> or <2>.

< 4 > At least one of the ink receiving layers is formed using a coating liquid containing a cation-modified latex resin having a volume average particle diameter of 0.001 μm to 0.1 μm. <1> It is an inkjet recording medium as described in any one of-< 3 >.
< 5 > At least one of the ink receiving layers is formed using a coating liquid containing fine particles having a dispersed particle diameter of 0.08 μm to 0.14 μm, and at least one other layer has a dispersed particle diameter of 0.10 μm to The inkjet recording medium according to any one of <1> to < 4 >, wherein the medium is formed using a coating solution containing fine particles of 0.20 μm.
< 6 > The ink jet recording medium according to < 5 >, wherein the layer formed using the coating liquid containing fine particles having a dispersed particle diameter of 0.08 μm to 0.14 μm is the uppermost layer. .

  According to the present invention, it is possible to provide an ink jet recording medium in which the occurrence of bronzing is suppressed in an ink jet recording medium in which at least two ink receiving layers are formed.

[Layer structure of inkjet recording medium]
Hereinafter, the layer structure of the ink jet recording medium in the present invention will be described in detail.
In the present specification, the ink receiving layer that is the outermost layer farthest from the support is sometimes referred to as the “uppermost layer”, and other ink receiving layers other than the uppermost layer may be referred to as the “lower layer”.

The ink jet recording medium of the present invention is formed by forming at least two ink receiving layers containing fine particles and a hydrophilic binder, and the formed ink receiving layer includes at least an uppermost layer and a cation that is more cationic than the uppermost layer. sex concentration of the substance (salt group polyaluminum hydroxide) is one that was constructed de high ink-receiving layer (lower layer). In a system in which the concentration of the basic polyaluminum hydroxide in the lower layer is higher than that in the uppermost layer, other cationic substances may be included in addition to the basic polyaluminum hydroxide.

  The ink receiving layer may be formed in three or more layers. Even in that case, it is necessary that the ink receiving layer having a higher concentration of the cationic substance than the uppermost layer is present in at least one of the lower layers except the uppermost layer. Further, the “ink receiving layer having a higher concentration of the cationic substance than the uppermost layer” is preferably a lower layer in direct contact with the uppermost layer. The uppermost layer may or may not contain a cationic substance.

  In the present invention, the “cationic substance” includes a water-soluble polyvalent metal salt and a cationic polymer. The concentration of the cationic substance is expressed as a mass ratio with respect to the fine particles.

The state where the concentration of the cationic substance in any one layer in the lower layer is higher than the concentration of the cationic substance in the uppermost layer means a state where the concentration ratio of the cationic substance in the following formula 1 is smaller than 100%.
Concentration ratio of cationic substance (%) = ((concentration of uppermost cationic substance) / (concentration of any one of the lower layer cationic substances)) × 100 (%) Formula 1

  The concentration ratio of the cationic substance in the present invention is such that the concentration of the cationic substance in the uppermost layer is 90% or less of the concentration of the cationic substance in any one of the lower layers from the viewpoint of the effect of suppressing bronzing. Is preferably 70% or less, and more preferably 50% or less.

The concentration of the uppermost cationic substance is preferably 1 to 30% by mass, and more preferably 3 to 25% by mass with respect to the fine particles.
Moreover, 5-30 mass% is preferable and, as for the density | concentration of any one layer among the lower layers, 7-25 mass% is more preferable.

  In the present invention, the ink receiving layer having the above-described configuration can prevent the cyan dye from being deposited on the surface of the uppermost layer. As a result, the occurrence of bronzing can be prevented.

  In the present invention, bronzing refers to a phenomenon in which a cyan dye is deposited on the surface of the uppermost layer, and a bronze-like metallic luster that is reddish in a printed portion having a high blue density.

  This tendency is particularly remarkable when a highly polar cationic substance such as basic polyaluminum hydroxide is used. Therefore, for example, in the above configuration, a mode in which a highly polar cationic substance such as basic polyaluminum hydroxide is not included in the uppermost layer and is included in only one of the lower layers is more preferable.

The ink jet recording medium of the present invention can be an ink jet recording medium in which the occurrence of bronzing is suppressed by adopting the above configuration.
Hereinafter, the constituents of the ink jet recording medium of the present invention will be described in detail, but the present invention is not limited to these explanatory items, exemplified compounds and the like.

(Ink receiving layer)
The ink receiving layer in the invention comprises at least fine particles and a hydrophilic binder. Of the plurality of ink receiving layers, at least the lower layer excluding the uppermost layer is configured to contain a cationic substance. Furthermore, you may be comprised including a crosslinking agent and another component as needed. Hereinafter, each of these components will be described in detail.

(Fine particles)
The fine particles in the present invention can contain both inorganic fine particles and organic fine particles.
The fine particles in the present invention preferably have an average primary particle diameter of 50 nm or less, more preferably 30 nm or less, and particularly preferably 15 nm or less. When the average primary particle diameter of the fine particles is 15 nm or less, the ink absorption characteristics can be effectively improved, and at the same time, the glossiness of the ink receiving layer surface can be enhanced. The lower limit of the average primary particle diameter of the fine particles is not particularly limited, but is preferably 1 nm or more. Among these, for example, it is preferable to contain at least one kind of fine particles selected from organic fine particles, silica fine particles, alumina fine particles, and pseudo boehmite type aluminum hydroxide fine particles.

  Among the fine particles, gas phase method silica or gas phase method alumina produced by the gas phase method has a particularly large specific surface area, so that the ink absorption and retention efficiency is high and the refractive index is low. Dispersion to such a small particle size is preferable because it can provide transparency to the ink receiving layer, and can provide high color density and good color development. Thus, the fact that the receiving layer is transparent means that not only for applications that require transparency, such as OHP, but also when applied to recording sheets such as photo glossy paper, a high color density and good color developability and This is important from the viewpoint of obtaining glossiness.

  In particular, the silica fine particle has a silanol group on the surface thereof, and the particles easily adhere to each other by hydrogen bonding of the silanol group, and because of the adhesion effect between the particles via the silanol group and the hydrophilic binder, As described above, when the average primary particle diameter is 15 nm or less, the ink receiving layer has a high porosity and a highly transparent structure can be formed, and the ink absorption characteristics can be effectively improved.

  In general, silica fine particles are generally roughly classified into wet method (precipitation method) particles and dry method (gas phase method) particles according to the production method. In the wet method, a method is mainly used in which active silica is produced by acid decomposition of silicate, and this is appropriately polymerized and coagulated 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. The method of obtaining anhydrous silica by the (arc method) is the mainstream, and the “gas phase method silica” refers to anhydrous silica fine particles obtained by the gas phase method.

Vapor phase method silica is different from the hydrous silica in 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 high porosity. The reason for this is not clear, but in the case of hydrous silica, the density of silanol groups on the surface of the fine particles is as high as 5 to 8 / nm ^2, and the silica fine particles tend to agglomerate closely (aggregate). In the case of the method silica, the density of silanol groups on the surface of the fine particles is as small as ² to 3 / nm ² , so that it becomes sparse soft agglomeration (flocculate), and as a result, it is estimated that the structure has a high porosity. The

The fine particles in the present invention are preferably amorphous silica or alumina synthesized by a sedimentation method or a gas phase method. In particular, gas phase method silica or gas phase method alumina having an average primary particle diameter of 1 nm or more and 30 nm or less is preferably used, and the gas phase method silica or gas phase method alumina is used in an amount of 50% by mass or more (preferably 70% by mass). % Or more, more preferably 90% by mass or more). In the case of vapor phase method silica, silica fine particles having a density of silanol groups on the fine particle surface of 2 to 3 / nm ² are preferred.

  In the present invention, vapor-phase process alumina has a feature that it has a higher color density and higher gloss than gas-phase process silica. This is presumably because the refractive index of vapor-phase method alumina is higher than that of vapor-phase method silica and the reflection of light on the surface is strong. Vapor phase alumina has the characteristics of spherical particles and excellent ink absorbency compared to alumina hydrate such as pseudoboehmite, and further improves ink absorbency when combined with the present invention. It becomes possible to make it. Although the reason is not clear, vapor-phase method alumina has a feature that microcracks of the ink receiving layer are less likely to occur compared to vapor-phase method silica. Such micro cracks are caused by various factors in the manufacturing process, but when combined with vapor phase alumina, for example, the micro cracks caused by shrinkage of the coating during the drying process are greatly improved. It becomes possible to do.

  In addition, when vapor-phase process alumina is used, the strength of the coating film tends to be higher than when vapor-phase process silica is used, and failure such as scratches is less likely to occur. Furthermore, it is possible to increase the solid content of the pigment dispersion compared to gas phase method silica, so it is possible to increase the solid content of the final coating liquid, and the production with low drying load and high productivity. It also has the advantage that it can be manufactured by the method. When preparing an aqueous dispersion of vapor-phase process alumina, the use of a small amount of an acidic component can further increase the dispersed solid content. As such an acidic component, it is particularly preferable to add a small amount of boric acid when dispersing the pigment.

  In order to increase the pigment dispersion concentration, it is preferable to use a known dispersant. As these dispersants, for example, a cationic polymer having a secondary, tertiary amino group, or quaternary ammonium base, a nonionic or cationic surfactant, and a low molecular weight polyvinyl alcohol are preferably used in combination. .

When vapor phase alumina is used as the fine particles, the preferred amount is 4 to 12 parts by weight, more preferably 5 to 10 parts by weight, and particularly preferably 6 to 1 part by weight of the hydrophilic binder described below. It is possible to obtain sufficient film strength with a smaller amount of binder than when using vapor phase method silica.
In the case of an ink receiving layer having a multilayer structure, it is preferable to include vapor phase method alumina in the outermost layer in order to bring out the characteristics of the vapor phase method alumina.

  In the present invention, the fine particles may be used alone or in combination of two or more. When two or more kinds of fine particles are used in combination, a mode in which precipitation method silica, gas phase method silica, and gas phase method alumina are optionally used in combination is preferable.

  When organic fine particles are used as the fine particles in the present invention, it is necessary to exist in the form of particles when the ink receiving layer is formed. Examples of the organic fine particles include polymer fine particles obtained by emulsion polymerization, microemulsion polymerization, soap-free polymerization, seed polymerization, dispersion polymerization, suspension polymerization, and the like. Specifically, polyethylene, polypropylene, polystyrene, Examples include polyacrylate, polyamide, silicon resin, phenol resin, natural polymer powder, latex or emulsion polymer fine particles, and the like. The organic fine particles preferably have a cationized surface. The Tg of the organic fine particles is not particularly limited, but when used alone, it is preferably 40 ° C. or higher, more preferably 80 ° C. or higher.

<Dispersed particle size of fine particles>
Here, the dispersed particle size of the fine particles in the present invention will be described.
The dispersed particle size of the fine particles in the coating solution for the uppermost layer is preferably 0.05 μm to 0.20 μm, more preferably 0.08 μm to 0.14 μm, from the viewpoint of improving glossiness and black density.

  From the viewpoint of ink absorbability and black density, the dispersed particle size of the fine particles of the lower layer coating solution is preferably 0.05 μm to 0.30 μm, and more preferably 0.10 μm to 0.20 μm.

  The dispersed particle size in the present invention is a volume average dispersed particle size, and was measured by a measuring instrument LA-920 (manufactured by Horiba, Ltd.) immediately before coating after fine particles were dispersed in a solvent to prepare a coating solution. Value.

  The content of the fine particles in the uppermost layer or the lower layer is preferably 50 to 90% by mass and more preferably 60 to 80% by mass with respect to the solid content of each layer.

(Hydrophilic binder)
The ink receiving layer in the invention contains a hydrophilic binder.
Examples of the hydrophilic binder used in the present invention 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.], cellulosic resins [methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC), hydroxypropyl cellulose (HPC), hydroxyethyl methyl cellulose, hydroxy Propylmethylcellulose, etc.), chitins, chitosans, starch, resins having ether linkages (polyethylene oxy Id (PEO), polypropylene oxide (PPO), polyethylene glycol (PEG), polyvinyl ether (PVE), etc.], resins having a carbamoyl group [polyacrylamide (PAAM), polyvinylpyrrolidone (PVP), polyacrylic acid hydrazide, etc.), etc. Is mentioned.
Moreover, the polyacrylic acid salt which has a carboxyl group as a dissociable group, maleic acid resin, alginate, gelatins, etc. can be mentioned.

  In the ink receiving layer in the present invention, from the viewpoint of ink absorbability, among the hydrophilic binders described above, polyvinyl alcohol resins, cellulose resins, resins having an ether bond, resins having a galvamoyl group, resins having a carboxy group And at least one selected from gelatins is more preferable.

Among the above, the hydrophilic binder in the present invention is particularly preferably polyvinyl alcohol (PVA).
The degree of saponification of the polyvinyl alcohol (PVA) used in the present invention is preferably 75 to 95 mol%, more preferably 77 to 90 mol%, and particularly preferably 80 to 90 mol% from the viewpoint of color density. Moreover, as a polymerization degree of polyvinyl alcohol (PVA), from a viewpoint of obtaining sufficient film | membrane intensity | strength, 1400-5000 are preferable and 2300-4000 are more preferable. Polyvinyl alcohol having a polymerization degree of less than 1400 and a polymerization degree of 1400 or more may be used in combination.

As the content of the hydrophilic binder in the ink receiving layer, the film strength is prevented from being lowered or cracked during drying due to the excessive content, and the void is blocked by the resin due to the excessive content. From the viewpoint of preventing the ink absorbency from being lowered by decreasing the porosity, the content is preferably 5 to 40% by mass with respect to the total solid content contained in the ink receiving layer, and 10 to 30%. The mass% is more preferable.
Note that the below-described fine particles that mainly constitute the ink receiving layer and the hydrophilic binder may each be a single material or a mixed system of a plurality of materials.

  In addition to unmodified polyvinyl alcohol (PVA), the polyvinyl alcohol includes cation-modified PVA, anion-modified PVA, silanol-modified PVA, and other polyvinyl alcohol derivatives. Polyvinyl alcohol may be used alone or in combination of two or more.

The PVA has a hydroxyl group in its structural unit, and this hydroxyl group and the silanol group on the surface of the silica fine particle form a hydrogen bond, and it is easy to form a three-dimensional network structure in which the secondary particle of the silica fine particle is a chain unit. To do. By forming such a three-dimensional network structure, it is considered that an ink receiving layer having a porous structure with a high porosity can be formed.
In the ink jet recording medium obtained by the present invention, the porous ink receiving layer obtained as described above absorbs ink rapidly by capillary action, and forms dots with good roundness without ink bleeding. can do.

<Content ratio of fine particles and hydrophilic binder>
In the present invention, the content ratio of the fine particles (preferably silica fine particles; x) to the hydrophilic binder (y) [PB ratio (x / y), the mass of fine particles relative to 1 part by mass of the hydrophilic binder] The film structure is also greatly affected. That is, as the PB ratio increases, the porosity, pore volume, and surface area (per unit mass) increase. Specifically, as the PB ratio (x / y), a decrease in film strength and cracking during drying caused by the PB ratio being too large are prevented, and the PB ratio is too small. The ratio is preferably 1.5 / 1 to 10/1 from the viewpoint of preventing the void from being easily blocked by the resin and preventing the ink absorbability from being lowered due to the decrease in the void 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, the ink receiving layer needs to have sufficient film strength to prevent cracking and peeling of the ink receiving layer. From such a viewpoint, the PB ratio (x / y) is preferably 6/1 or less, and preferably 3/1 or more from the viewpoint of securing high-speed ink absorbability with an inkjet printer.

For example, a coating solution in which anhydrous silica fine particles having an average primary particle size of 20 nm or less and a hydrophilic binder are completely dispersed in an aqueous solution with a PB ratio (x / y) of 3/1 to 6/1 is coated on a support. When the coating layer is dried, a three-dimensional network structure in which the secondary particles of silica fine particles are chain units is formed, the average pore diameter is 30 nm or less, the porosity is 50% to 80%, and the pore specific volume is 0. A translucent porous film having a surface area of 5 ml / g or more and a specific surface area of 100 m ² / g or more can be easily formed.

(Cationic substance)
Of the ink receiving layer in the invention, at least the lower layer contains a cationic substance. The cationic substance in the present invention includes water-soluble polyvalent metal salts and cationic polymers. Hereinafter, the water-soluble polyvalent metal salt and the cationic polymer suitable for the present invention will be mainly described.

<Water-soluble polyvalent metal salt>
The ink jet recording medium of the present invention preferably contains a water-soluble polyvalent metal salt in the ink receiving layer in order to improve the water resistance and bleed resistance of the formed image.

Examples of the water-soluble polyvalent metal salt include water-soluble salts of metals selected from calcium, barium, manganese, copper, cobalt, nickel, aluminum, iron, zinc, zirconium, chromium, magnesium, tungsten, and molybdenum.
Specifically, calcium acetate, calcium chloride, calcium formate, calcium sulfate, barium acetate, barium sulfate, barium phosphate, manganese chloride, manganese acetate, manganese formate dihydrate, manganese ammonium sulfate hexahydrate, second chloride Copper, ammonium chloride (II) chloride dihydrate, copper sulfate, cobalt chloride, cobalt thiocyanate, cobalt sulfate, nickel sulfate hexahydrate, nickel chloride hexahydrate, nickel acetate tetrahydrate, nickel ammonium sulfate Hexahydrate, nickel amidosulfate tetrahydrate, aluminum sulfate, aluminum sulfite, aluminum thiosulfate, polyaluminum chloride, aluminum nitrate nonahydrate, aluminum chloride hexahydrate, ferrous bromide, ferrous chloride Iron, ferric chloride, ferrous sulfate, ferric sulfate, zinc bromide, zinc chloride, zinc nitrate hexahydrate , Zinc sulfate, Zirconyl acetate, Zirconium chloride, Zirconium chloride oxide octahydrate, Hydroxy zirconium chloride, Chromium acetate, Chromium sulfate, Magnesium sulfate, Magnesium chloride hexahydrate, Magnesium citrate nonahydrate, Sodium phosphotungstate Sodium tungsten citrate, 12 tungstophosphoric acid n hydrate, 12 tungstosilicic acid 26 hydrate, molybdenum chloride, 12 molybdophosphoric acid n hydrate, and the like.

  The water-soluble polyvalent metal salt is preferably at least one selected from water-soluble aluminum compounds, zirconium compounds and titanium compounds.

  As an 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, there is basic polyaluminum hydroxide which is an inorganic aluminum-containing cationic polymer. In particular, basic polyaluminum hydroxide is preferred from the viewpoint of ozone resistance.

-Basic polyaluminum hydroxide-
Basic polyaluminum hydroxide has a main component represented by the following formula 2, 3 or 4, 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 are water-soluble basic polyaluminum hydroxides that stably contain basic and high-molecular polynuclear condensed ions.

[Al ₂ (OH) _n Cl _6-n ] _m
[Al (OH) ₃ ] _n AlCl ₃ Formula 3
Al _n (OH) _m Cl _(3n-m) 0 <m <3n Formula 4

  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. It is marketed under the name of Purachem WT and from other manufacturers for the same purpose, and various grades can be easily obtained. In the present invention, these commercially available products can be used as they are, but there are also products having an inappropriately low pH, and in that case, the pH can be appropriately adjusted and used.

Since basic polyaluminum hydroxide is a highly polar cationic substance, it has excellent ozone resistance. Here, ozone resistance is a very important characteristic in terms of preventing fading of a recorded image over time.
On the other hand, when basic polyaluminum hydroxide is contained in the uppermost layer, the cyan dye may precipitate on the uppermost layer surface and cause bronzing.
From the above, it is preferable that the basic polyaluminum hydroxide is not contained in the uppermost layer but contained only in the lower layer other than the uppermost layer.

-Water-soluble zirconium compound-
The water-soluble zirconium compound is not particularly limited and various compounds can be used. For example, zirconyl acetate, zirconium chloride, zirconium oxychloride, hydroxy zirconium chloride, zirconium nitrate, basic zirconium carbonate, zirconium hydroxide, zirconium carbonate Ammonium, zirconium carbonate / potassium carbonate, zirconium sulfate, zirconium fluoride compound and the like can be mentioned. Zirconyl acetate is particularly preferable.

  Some of these compounds have an inappropriately low pH. In that case, the pH can be appropriately adjusted and used. In the present invention, the term “water-soluble” means that 1% by mass or more dissolves in water at room temperature and normal pressure.

In the present invention, when several kinds of water-soluble polyvalent metal salts are used, it is particularly preferable that at least one of them is zirconyl acetate from the viewpoint of imparting a bleeding suppression effect to a wider range of dyes. The content of zirconyl acetate in the ink receiving layer, is preferably 0.3 g / m ² or less, 0.01~0.02g / m ² is more preferable.

  In addition, when using zirconyl acetate, it is preferable from the viewpoint of viscosity stability of the coating liquid that zirconyl acetate is previously contained in the fine particle dispersion, and then the dispersion and the binder are mixed. More preferably, the dispersion treatment is performed in the presence of zirconyl acetate in advance in the liquid containing the fine particles before the dispersion treatment.

  In the present invention, the content of the water-soluble polyvalent metal salt in the ink receiving layer is preferably from 0.1 to 20% by mass, more preferably from 1 to 10% by mass, based on the fine particles.

-Preferred embodiment of water-soluble polyvalent metal salt-
In the present invention, the content of the water-soluble polyvalent metal salt in the ink receiving layer is preferably 1 to 30% by mass, more preferably 5 to 25% by mass, based on the fine particles.
In addition, the water-soluble polyvalent metal salt can be used alone, but it is preferable to use two or more kinds in combination.
In the present invention For example, in order to achieve a high color density, Ru using at least water soluble zirconyl compound in the top layer. On the other hand, for example, basic polyaluminum hydroxide can be used in a layer other than the uppermost layer in order to suppress the occurrence of bronzing while suppressing bleeding of the dye and improving ozone resistance.

<Cationic polymer>
The ink jet recording medium of the present invention can be suitably configured using a cationic polymer as a cationic substance. Hereinafter, the cation-modified latex resin and other cationic polymers will be described separately.

-Cation-modified latex resin-
The ink receiving layer in the invention may contain a cation-modified latex resin (hereinafter sometimes simply referred to as “latex resin”).
In the present invention, the latex resin refers to a colloidal dispersion having a volume average particle diameter of 0.001 to 0.1 μm or an emulsion liquid having a volume average particle diameter of 0.1 to 10 μm.
The latex resin in the present invention is a cation-modified polymer having a volume average particle size of 0.001 to 0.1 μm (preferably 0.001 to 0.05 μm, more preferably 0.001 to 0.01 μm). The colloidal dispersion is preferably included.

  More specifically, as the cation-modified polymer contained in the latex resin in the present invention, for example, a polyaddition system or a polycondensation system having a cationic group such as a primary to tertiary amino group or a quaternary ammonium group. A high molecular compound is mentioned.

  Examples of the vinyl polymerization polymer effective as a cation-modified polymer include polymers obtained by polymerizing the following vinyl monomers. That is, acrylic acid esters and methacrylic acid esters (the ester group is an alkyl group or aryl group which may have a substituent, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n- Butyl group, sec-butyl group, tert-butyl group, hexyl group, 2-ethylhexyl group, tert-octyl group, 2-chloroethyl group, cyanoethyl group, 2-acetoxyethyl group, tetrahydrofurfuryl group, 5-hydroxypentyl group Cyclohexyl group, benzyl group, hydroxyethyl group, 3-methoxybutyl group, 2- (2-methoxyethoxy) ethyl group, 2,2,2-tetrafluoroethyl group, 1H, 1H, 2H, 2H-perfluorodecyl Group, phenyl group, 2,4,5-tetramethylphenyl group, 4-chlorophenyl group, etc.);

  Vinyl esters, specifically, aliphatic carboxylic acid vinyl esters which may have a substituent (for example, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl caproate, vinyl Chloroacetate, etc.), optionally substituted aromatic carboxylic acid vinyl ester (for example, vinyl benzoate, vinyl 4-methylbenzoate, vinyl salicylate, etc.);

  Acrylamides, specifically, acrylamide, N-monosubstituted acrylamide, N-disubstituted acrylamide (the substituent is an alkyl group, aryl group, silyl group which may have a substituent, such as a methyl group, n-propyl group, isopropyl group, n-butyl group, tert-butyl group, tert-octyl group, cyclohexyl group, benzyl group, hydroxymethyl group, alkoxymethyl group, phenyl group, 2,4,5-tetramethylphenyl group , 4-chlorophenyl group, trimethylsilyl, etc.);

  Methacrylamide, specifically, methacrylamide, N-monosubstituted methacrylamide, N-disubstituted methacrylamide (substituents are optionally substituted alkyl, aryl, silyl groups, for example , Methyl group, n-propyl group, isopropyl group, n-butyl group, tert-butyl group, tert-octyl group, cyclohexyl group, benzyl group, hydroxymethyl group, alkoxymethyl group, phenyl group, 2,4,5- Tetramethylphenyl group, 4-chlorophenyl group, trimethylsilyl, etc.);

  Olefins (for example, ethylene, propylene, 1-pentene, vinyl chloride, vinylidene chloride, isoprene, chloroprene, butadiene, etc.), styrenes (for example, styrene, methylstyrene, isopropylstyrene, methoxystyrene, acetoxystyrene, chlorostyrene, etc.) Vinyl ethers (for example, methyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, methoxyethyl vinyl ether, etc.);

  Other vinyl monomers include crotonic acid ester, itaconic acid ester, maleic acid diester, fumaric acid diester, methyl vinyl ketone, phenyl vinyl ketone, methoxyethyl vinyl ketone, N-vinyl oxazolidone, N-vinyl pyrrolidone, methylene malon nitrile, diphenyl Examples include 2-acryloyloxyethyl phosphate, diphenyl-2-methacryloyloxyethyl phosphate, dibutyl-2-acryloyloxyethyl phosphate, dioctyl-2-methacryloyloxyethyl phosphate, and the like.

  Examples of the monomer having a cationic group include monomers having a tertiary amino group such as dialkylaminoethyl methacrylate and dialkylaminoethyl acrylate.

Examples of the polyurethane applicable to the cation-modified polymer include polyurethanes synthesized by a polyaddition reaction using various combinations of the following diol compounds and diisocyanate compounds.
Specific examples of the diol compound include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 2,2 -Dimethyl-1,3-propanediol, 1,2-pentanediol, 1,4-pentanediol, 1,5-pentanediol, 2,4-pentanediol, 3,3-dimethyl-1,2-butanediol, 2 -Ethyl-2-methyl-1,3-propanediol, 1,2-hexanediol, 1,5-hexanediol, 1,6-hexanediol, 2,5-hexanediol, 2-methyl-2,4-pentanediol 2,2-diethyl-1,3-propanediol, 2,4-dimethyl-2,4-pentanediol, 1,7-heptane All, 2-methyl-2-propyl-1,3-propanediol, 2,5-dimethyl-2,5-hexanediol, 2-ethyl-1,3-hexanediol, 1,2-octanediol, 1, 8-octanediol, 2,2,4-trimethyl-1,3-pentanediol, 1,4-cyclohexanedimethanol, hydroquinone, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol (average molecular weight = 200,300,400,600,1000,1500,4000), polypropylene glycol (average molecular weight = 200,400,1000), polyester polyol, 4,4′-dihydroxy-diphenyl-2,2-propane, 4,4 ′ -Dihydroxyphenyls Examples include ruphone and polycarbonate polyol.

  Examples of the diisocyanate compound include methylene diisocyanate, ethylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, 1,4-cyclohexane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,3-xylylene diisocyanate, 1, 5-naphthalene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 3,3′-dimethyl-4,4′-diphenylmethane diisocyanate, 3,3′-dimethylbiphenylene diisocyanate, 4,4′-biphenylene diisocyanate, dicyclohexylmethane diisocyanate , Methylenebis (4-cyclohexylisocyanate) and the like.

Examples of the cationic group contained in the polyurethane having a cationic group include cationic groups such as primary to tertiary amines and quaternary ammonium salts. The polymer used for the latex in the present invention is preferably a urethane resin having a cationic group such as a tertiary amine and a quaternary ammonium salt.
The polyurethane having a cationic group can be obtained, for example, by using a polyurethane in which a cationic group is introduced as described above during the synthesis of polyurethane. In the case of a quaternary ammonium salt, a polyurethane containing a tertiary amino group may be quaternized with a quaternizing agent.

  The diol compound and diisocyanate compound that can be used for the synthesis of the polyurethane may be used alone or in various ways (for example, adjustment of the glass transition temperature (Tg) of the polymer and improvement of solubility, Depending on the compatibility with the binder, improvement of the stability of the dispersion, etc., two or more of them can be used in any proportion.

Furthermore, examples of the polyester applicable to the cation-modified polymer include polyesters synthesized by a polycondensation reaction using various combinations of the following diol compounds and dicarboxylic acid compounds.
Examples of the dicarboxylic acid compound include oxalic acid, malonic acid, succinic acid, glutaric acid, dimethylmalonic acid, adipic acid, pimelic acid, α, α-dimethylsuccinic acid, acetone dicarboxylic acid, sebacic acid, and 1,9-nonanedicarboxylic acid. Acid, fumaric acid, maleic acid, itaconic acid, citraconic acid, phthalic acid, isophthalic acid, terephthalic acid, 2-butyl terephthalic acid, tetrachloroterephthalic acid, acetylenedicarboxylic acid, poly (ethylene terephthalate) dicarboxylic acid, 1,2- Examples include cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, ω-poly (ethylene oxide) dicarboxylic acid, and p-xylylene dicarboxylic acid.

  When performing the polycondensation reaction with the diol compound, the dicarboxylic acid compound may be used in the form of an alkyl ester of dicarboxylic acid (for example, dimethyl ester) and an acid chloride of dicarboxylic acid, or maleic anhydride, anhydrous You may use in the form of an acid anhydride like succinic acid and phthalic anhydride.

  As the diol compound, the same compounds as the diols exemplified in the polyurethane can be used.

  The polyester having a cationic group can be obtained by synthesis using a dicarboxylic acid compound having a cationic group such as a primary, secondary, tertiary amine or quaternary ammonium salt.

  The diol compounds, dicarboxylic acids, and hydroxycarboxylic acid ester compounds used in the synthesis of the polyester may be used alone or in various ways (for example, adjustment of the glass transition temperature (Tg) of the polymer). Or two or more of them may be mixed and used in an arbitrary ratio depending on the solubility, compatibility with the dye, and stability of the dispersion.

  The content of the cationic group in the cation-modified polymer is preferably 0.1 to 5 mmol / g, and more preferably 0.2 to 3 mmol / g. In addition, when there is too little content of the said cationic group, the dispersion stability of a polymer will become small, and when too large, compatibility with a binder will fall.

  The cation-modified polymer is preferably a polymer having a cationic group such as a tertiary amino group or a quaternary ammonium base, and particularly preferably a urethane resin having a cationic group as described above.

  When the cation-modified polymer is used for the ink receiving layer, the glass transition temperature is particularly important. In order to suppress bleeding of the image over time after the image is formed by ink jet recording, it is preferable that the glass transition temperature of the cation-modified polymer is less than 50 ° C. Further, the cation-modified polymer having a glass transition temperature of 30 ° C. or lower is more preferable, and a glass transition temperature of 15 ° C. or lower is most preferable. When the glass transition temperature is 50 ° C. or higher, dimensional stability (curl) may be deteriorated. In addition, although there is no restriction | limiting in particular in the minimum of the said glass transition temperature, In normal use, it is about -30 degreeC, and if lower than this, the manufacturability at the time of preparing an aqueous dispersion may fall.

  The weight average molecular weight (Mw) of the cation-modified polymer contained in the latex resin is usually preferably from 1,000 to 1,000,000, more preferably from 300,000 to 700,000. When the molecular weight is 1,000 to 1,000,000, a stable aqueous dispersion is easily obtained, the solubility is not lowered and the liquid viscosity is not increased, and the average particle size of the aqueous dispersion is reduced. In particular, it is easy to control to 0.05 μm or less.

  The content of the cation-modified polymer in the latex resin is preferably determined to be 0.1 to 30% by mass of the total solid content of the ink receiving layer, and is 0.3 to 20% by mass. Is more preferable, and 0.5 to 15% by mass is particularly preferable. When the content is in the range of 0.1 to 30% by mass, the effect of improving bleeding over time can be sufficiently exerted, and the ratio of fine particles and binder components to be described later is reduced, and the ink absorbability to high-quality recording paper is reduced. There is no decline.

  The latex resin in the present invention is a colloidal dispersion containing a cationic urethane resin having a volume average particle size of 30 nm or less from the viewpoint of obtaining such a gloss for photographic use, and the glass transition temperature of the cationic urethane resin is Those having a temperature of less than 50 ° C. are particularly preferred.

  Commercially available products may be used as the latex resin in the present invention. For example, “Superflex 650”, “Superflex 620”, “Superflex 610”, “Superflex 600” manufactured by Daiichi Kogyo Seiyaku Co., Ltd. And so on.

Next, a method for preparing a latex resin in the present invention will be described.
In the cation-modified latex resin of the present invention, the cation-modified polymer is mixed with an aqueous solvent, an additive is mixed as necessary, and the mixture is finely divided using a disperser. Thus, it can be obtained as an aqueous dispersion. As the disperser used to obtain the aqueous dispersion, various conventionally known dispersers such as a high-speed rotary disperser, an ultrasonic disperser, a colloid mill disperser, and a high-pressure disperser can be used. From the viewpoint of efficiently dispersing the lumpy fine particles, a high-pressure disperser is preferable.

  A high-pressure disperser (homogenizer) has a detailed mechanism described in US Pat. No. 4,533,254, JP-A-6-47264, etc., but as a commercially available apparatus, a Gorin homogenizer (APV GAULIN INC.), Microfluidizer (MICROFLUIDEX INC.), Optimizer (Sugino Machine Co., Ltd.), etc. can be used. In recent years, a high-pressure homogenizer having a mechanism for atomizing in an ultrahigh-pressure jet stream as described in US Pat. No. 5,720,551 is particularly effective for emulsification and dispersion in the present invention. DeBEE2000 (BEE INTERNATIONAL LTD.) Can be cited as an example of an emulsifier using this ultra-high pressure jet stream. Among these, a high-pressure jet disperser is particularly preferable because it is easy to obtain the single dispersibility of the fine particles in the present invention, the haze of the ink receiving layer can be reduced, and a high porosity can be obtained.

  Water, an organic solvent, or a mixed solvent thereof can be used as the aqueous solvent in the dispersion step. Examples of the organic solvent that can be used for the dispersion 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.

  The cation-modified polymer contained in the latex resin of the present invention can itself become a naturally stable emulsified dispersion, but a small amount of dispersing agent is used in order to make the emulsified dispersion more quickly or more stable. (Surfactant) may be used. Surfactants used for such purposes include, for example, fatty acid salts, alkyl sulfate esters, alkylbenzene sulfonates, alkyl naphthalene sulfonates, dialkyl sulfosuccinates, alkyl phosphate esters, naphthalene sulfonate formalin condensates. , Anionic surfactants such as polyoxyethylene alkyl sulfates, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene Nonionic surfactants such as alkylamines, glycerin fatty acid esters and oxyethyleneoxypropylene block copolymers are preferred. Further, SURFYNOLS (Air Products & Chemicals), which is an acetylene-based polyoxyethylene oxide surfactant, is also preferably used. An amine oxide type amphoteric surfactant such as N, N-dimethyl-N-alkylamine oxide is also preferred. Further, pages (37) to (38) of JP-A-59-157,636, Research Disclosure No. Those listed as surfactants described in 308119 (1989) can also be used.

  In order to stabilize immediately after emulsification, a water-soluble polymer can be added in combination with the surfactant. As the water-soluble polymer, polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene oxide, polyacrylic acid, polyacrylamide or a copolymer thereof is preferably used. It is also preferable to use natural water-soluble polymers such as polysaccharides, casein, and gelatin.

  When dispersing a cation-modified polymer in an aqueous medium by the emulsification dispersion method, it is particularly important to control the particle size. In order to increase color purity and color density when an image is formed by inkjet, it is necessary to reduce the average particle size of the cation-modified polymer in the aqueous dispersion.

-Other cationic polymers-
The ink receiving layer in the invention may further contain another cationic polymer.
As the other cationic polymer in the present invention, a polymer mordant having a primary to tertiary amino group or a quaternary ammonium base as a cationic group is preferably used, but a cationic non-polymer mordant may also be used. Can be used.
Examples of the other cationic polymer include a homopolymer of a monomer having a primary to tertiary amino group and a salt thereof, or a quaternary ammonium base (mordant monomer), and the mordant monomer and another monomer. (Hereinafter referred to as “non-mordant monomer”) is preferably obtained as a copolymer or condensation polymer. These polymers can be used in any form of water-soluble polymer or water-dispersible latex particles.

  Examples of the monomer (mordanting 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-N -P-vinylbenzylammonium chloride, N, N-dimethyl-Nn-octyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N-benzyl-Np-vinylbenzylammonium chloride, N, N-die Ru-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.

  Specifically, for example, monomethyl diallyl ammonium 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- (acryloylamino) ethyl Ammonium 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.
Other examples of the copolymerizable monomer include N-vinylimidazole and N-vinyl-2-methylimidazole.

In addition, allylamine, diallylamine, its derivatives, salts and the like can be used. Examples of such compounds are allylamine, allylamine hydrochloride, allylamine acetate, allylamine sulfate, diallylamine, diallylamine hydrochloride, diallylamine acetate, diallylamine sulfate, diallylmethylamine and salts thereof (for example, Hydrochloride, acetate, sulfate, etc.), diallylethylamine and salts thereof (for example, hydrochloride, acetate, sulfate, etc.), diallyldimethylammonium salt (chloride, acetic acid as counter anions of the salt) Ion sulfate ions, etc.). In addition, since these allylamines and diallylamine derivatives are inferior in polymerizability in the amine form, they are generally polymerized in the form of a salt and desalted as required.
In addition, a 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 also be used.

The non-mordant monomer does not contain a basic or cationic moiety such as a primary to tertiary amino group and a salt thereof, or a quaternary ammonium base, and does not show an interaction with a dye in an inkjet ink. Or the monomer which interaction is substantially small is said.
Examples of the non-mordant monomer include (meth) acrylic acid alkyl ester; (meth) acrylic acid cycloalkyl ester such as cyclohexyl (meth) acrylate; (meth) acrylic acid aryl ester such as phenyl (meth) acrylate; Aralkyl esters such as (meth) benzyl acrylate; Aromatic vinyls such as styrene, vinyl toluene and α-methylstyrene; Vinyl esters such as vinyl acetate, vinyl propionate and vinyl versatic acid; Allyl esters such as allyl acetate Halogen-containing monomers such as vinylidene chloride and vinyl chloride; vinyl cyanide 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, such as methyl (meth) acrylate, ethyl (meth) acrylate, (meth) Propyl acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, Examples include 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, and the like.
Of these, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, and hydroxyethyl methacrylate are preferable.
The non-mordant monomers can also be used singly or in combination of two or more.

Further, as the other cationic polymer, polydiallyldimethylammonium chloride, polymethacryloyloxyethyl-β-hydroxyethyldimethylammonium chloride, polyethyleneimine, polyallylamine and its derivatives, polyamide-polyamine resin, cationized starch, dicyandiamide formalin condensation , Dimethyl-2-hydroxypropylammonium salt polymer, polyamidine, polyvinylamine, dicyandiamide-formalin polycondensate, dicyanamide-cachin resin, dicyanamide-diethylenetriamine polycondensate, polyamine-type katine resin, epichlorohydrin- dimethylamine addition polymer, dimethyldiallylammonium phosphorus chloride -SO ₂ copolymers, diallylamine salt -SO ₂ co Compounds, mention may be made of quaternary ammonium base-substituted alkyl group having an ester moiety (meth) acrylate-containing polymers, as preferred styryl polymers having a quaternary ammonium base-substituted alkyl group.

  Specific examples of the other cationic polymer include JP-A Nos. 48-28325, 54-74430, 54-124726, 55-22766, 55-142339, and 60-23850. 60-23851, 60-23852, 60-23853, 60-57836, 60-60643, 60-118834, 60-122940, 60-122941, 60-122942, 60-235134, JP-A-1-161236, U.S. Pat.Nos. 2,484,430, 2,548,564, 3,148,061, 3,309,690, 4,115,124, 4,124,386, 4,193,800, Nos. 4,273,853, 4,282,305 and 4,450,224, JP-A-1-1-1 1236, 10-81064, 10-119423, 10-157277, 10-217601, 11-348409, JP-A-2001-138621, 2000-43401, 2000-212235 No. 2000-309157, No. 2001-96897, No. 2001-138627, JP-A-11-91242, No.8-2087, No.8-2090, No.8-2091, No.8-2093 8-1744992, 11-192777, JP-A-2001-301314, JP-B-5-35162, JP-A-5-35163, JP-A-5-35164, JP-A-5-88846, JP-A-7-118333. No. 2000-344990, Japanese Patent No. 2648847, No. 2666177, etc. Those such as the mounting and the like. Among these, a diallyldimethylammonium chloride type polymer or a (meth) acrylate-containing polymer having a quaternary ammonium base in the ester portion is preferable.

  As the other cationic polymer, a cationic polymer having a weight average molecular weight of 200,000 or less and an I / O value of 3.0 or less is particularly preferable from the viewpoint of preventing bleeding with time.

Another cationic polymer may be used individually by 1 type, and may use 2 or more types together. Moreover, you may use together another cationic polymer, another organic mordant, and / or an inorganic mordant.
The content of the other cationic polymer contained in the ink receiving layer formed in the present invention is preferably 1 to 30% by mass, and 2 to 15% by mass with respect to the total solid content in the ink receiving layer. Is more preferable, and 3-10 mass% is further more preferable.

(Crosslinking agent)
The ink receiving layer formed in the present invention preferably further contains a crosslinking agent capable of crosslinking the hydrophilic binder, and in particular, the hydrophilic binder is cured by a crosslinking reaction with the crosslinking agent capable of crosslinking the fine particles and the hydrophilic binder. An embodiment having a porous structure is preferred.

As the cross-linking agent, a suitable one may be selected as appropriate in relation to the hydrophilic binder contained in the ink receiving layer, and among them, a boron compound is preferable in that the cross-linking reaction is rapid. 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 , diboric acid). Salt (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} ), can be mentioned five borate _{(e.g., KB 5 O 8 · 4H 2} O, Ca 2 B 6 O 11 · 7H 2 O, CsB 5 O 5) or the like. of these, Borax, boric acid and borates are preferred because they can promptly cause a crosslinking reaction. Boric acid is particularly preferred, and it is most preferred to use them in combination with polyvinyl alcohol which is a hydrophilic binder.

  In the present invention, the crosslinking agent is preferably contained in an amount of 0.05 to 0.50 parts by mass, and 0.08 to 0.30 parts by mass with respect to 1.0 part by mass of the hydrophilic binder. More preferably. When the content of the crosslinking agent is within the above range, the hydrophilic binder can be effectively crosslinked to prevent cracks and the like.

When gelatin is used as the hydrophilic binder, the following compounds other than boron compounds can also be used as a crosslinking agent.
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 2,983,611; 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. The above crosslinking agents may be used alone or in combination of two or more.

  In the present invention, the cross-linking agent may be added to the ink-receiving layer coating solution and / or the coating solution for forming the adjacent layer of the ink-receiving layer when forming the ink-receiving layer, or the cross-linking agent in advance. The ink receiving layer coating liquid is coated on a support coated with a coating liquid containing or a crosslinker-free ink-receiving layer coating liquid is coated, and after drying, the cross-linking agent solution is overcoated and the ink receiving process is performed. A crosslinking agent can be supplied to the layer. From the viewpoint of production efficiency, it is preferable to add a cross-linking agent to the ink receiving layer coating solution or the coating solution for forming the adjacent layer, and to supply the cross-linking agent simultaneously with the formation of the ink receiving layer. In particular, it is preferably contained in the ink-receiving layer coating solution from the viewpoint of improving the image printing density and glossiness. Further, the concentration of the crosslinking agent in the ink receiving layer coating solution is preferably 0.05 to 10% by mass, and more preferably 0.1 to 7% by mass.

  For example, the crosslinking agent can be suitably applied as follows. Here, a boron compound will be described as an example. That is, when the ink receiving layer is a layer obtained by crosslinking and curing the coating layer coated with the ink receiving layer coating liquid (first coating liquid), the crosslinking curing is performed by (1) coating the coating layer by applying the coating liquid. Simultaneously with the formation, (2) during the dry coating of the coating layer formed by coating the coating solution and before the coating layer exhibits a reduced rate of drying, the pH is 7.1 or more The basic solution (second coating solution) is applied to the coating layer. The boron compound as the crosslinking agent may be contained in either the first coating liquid or the second coating liquid, or may be contained in both the first coating liquid and the second coating liquid.

(Other ingredients)
The ink receiving layer in the invention is constituted by containing the following components as required.
That is, for the purpose of suppressing the deterioration of the ink coloring material, various ultraviolet absorbers, antioxidants, anti-fading agents such as singlet oxygen quenchers may be included.
Examples of the ultraviolet absorber include cinnamic acid derivatives, benzophenone derivatives, benzotriazolylphenol derivatives, and the like. For example, α-cyano-phenyl cinnamate butyl, o-benzotriazole phenol, o-benzotriazole-p-chlorophenol, o-benzotriazole-2,4-di-t-butylphenol, o-benzotriazole-2,4 -Di-t-octylphenol etc. are mentioned. A hindered phenol compound can also be used as an ultraviolet absorber, and specifically, a phenol derivative in which one or more of at least 2-position or 6-position is substituted with a branched alkyl group is preferable.

  Moreover, a benzotriazole type ultraviolet absorber, a salicylic acid type ultraviolet absorber, a cyanoacrylate type ultraviolet absorber, an oxalic acid anilide type ultraviolet absorber, etc. can be used. For example, JP-A-47-10537, 58-111942, 58-21284, 59-19945, 59-46646, 59-109055, 63-53544. No. 36, Japanese Patent Publication No. 36-10466, No. 42-26187, No. 48-30492, No. 48-31255, No. 48-41572, No. 48-54965, No. 50-10726. No. 2,719,086, US Pat. No. 3,707,375, US Pat. No. 3,754,919, US Pat. No. 4,220,711, and the like. .

  A fluorescent brightening agent can also be used as an ultraviolet absorber, and examples thereof include a coumarin fluorescent brightening agent. Specifically, it is described in Japanese Patent Publication Nos. 45-4699 and 54-5324.

  Examples of the antioxidant include European Patent Publication No. 223739, Publication No. 309401, Publication No. 309402, Publication No. 310551, Publication No. 310552, Publication No. 4594416, German Publication No. 3435443, No. 54-48535, No. 60-107384, No. 60-107383, No. 60-125470, No. 60-125471, No. 60-125472, No. 60-287485, 60-287486, 60-287487, 60-287488, 61-160287, 61-185483, 61-2111079, 62-146678, 62-146680, 62-146679, 6 -282885, JP same 62-262047, JP-same 63-051174, JP-same 63-89877, JP-same 63-88380, JP-same 66-88381, JP-same 63-113536 JP;

  JP-A-63-163351, JP-A-63-203372, JP-A-63-224989, JP-A-63-251282, JP-A-63-267594, JP-A-63-182484, JP-A-1-239282, JP-A-2-262654, JP-A-2-71262, JP-A-3-121449, JP-A-4-29185, JP-A-4-291684, JP-A-5-61166, JP-A-5-119449, 5-188687, 5-188686, 5-110490, 5-110437, 5-170361, JP 48-43295, 48-33212, Examples thereof include those described in U.S. Pat. Nos. 4,814,262 and 4,980,275.

  Specifically, 6-ethoxy-1-phenyl-2,2,4-trimethyl-1,2-dihydroquinoline, 6-ethoxy-1-octyl-2,2,4-trimethyl-1,2-dihydroquinoline 6-ethoxy-1-phenyl-2,2,4-trimethyl-1,2,3,4-tetrahydroquinoline, 6-ethoxy-1-octyl-2,2,4-trimethyl-1,2,3 4, -tetrahydroquinoline, nickel cyclohexane acid, 2,2-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) -2-ethylhexane, 2-methyl-4-methoxy-diphenylamine, Examples include 1-methyl-2-phenylindole.

  These anti-fading agents may be used alone or in combination of two or more. The anti-fading agent may be water-solubilized, dispersed, emulsified, or contained in microcapsules. The addition amount of the anti-fading agent is preferably 0.01 to 10% by mass of the ink receiving layer coating solution.

  The ink receiving layer in the invention may contain a high boiling point organic solvent for preventing curling. The high-boiling organic solvent is preferably a water-soluble one. Examples of the water-soluble high-boiling organic solvent include ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, glycerin, diethylene glycol monobutyl ether (DEGMBE), Ethylene glycol monobutyl ether, glycerin monomethyl ether, 1,2,3-butanetriol, 1,2,4-butanetriol, 1,2,4-pentanetriol, 1,2,6-hexanetriol, thiodiglycol, tri Examples include alcohols such as ethanolamine and polyethylene glycol (weight average molecular weight of 400 or less). Diethylene glycol monobutyl ether (DEGMBE) is preferred.

The content of the high-boiling organic solvent in the ink-receiving layer coating solution is preferably 0.05 to 1% by mass, particularly preferably 0.1 to 0.6% by mass.
In addition, for the purpose of improving the dispersibility of the inorganic pigment fine particles, various inorganic salts, pH adjusting agents, and the like may contain acids and alkalis.

  Further, for the purpose of suppressing surface frictional charge and peeling charge, the metal oxide fine particles having electronic conductivity may contain various matting agents for the purpose of reducing the surface frictional characteristics.

[Support etc.]
As the support applied to the present invention, either a transparent support made of a transparent material such as plastic or 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. In addition, 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 is used as a support, and an ink receiving layer is provided on the label surface side. You can also.

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 a backlight display. Examples of such materials 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 of the ease of handling.

  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, etc .; polyesters 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 an opaque support body, 50-300 micrometers is preferable at the point of the ease of handling.
The surface of the support is preferably subjected to corona discharge treatment, glow discharge treatment, flame treatment, ultraviolet irradiation treatment or the like in order to improve wettability and adhesion.

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

As the pulp, chemical pulp (sulfate pulp or sulfite pulp) with few impurities is suitably used, and a pulp having a whiteness improved by performing a bleaching treatment 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. The 4 mesh residue is preferably 20% by 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 addition, the aspect which used the hydrotalcite compound as a catalyst deactivator of the catalyst of a high density polyethylene is preferable, As content in a high density polyethylene, 100-2,000 ppm with respect to the quantity of a high density polyethylene Is preferable, and 200 to 1,000 ppm is more preferable. As the antioxidant, it is preferable to use only a secondary antioxidant (particularly a phosphorus-based antioxidant), and the content in the high-density polyethylene to be formed is 100 ppm or more 2 with respect to the high-density polyethylene (HDPE). 1,000 ppm or less is preferable, and 200 ppm or more and 1,000 ppm or less is more preferable.

  In particular, the polyethylene layer on the side on which the ink receiving layer is formed is obtained by adding rutile or anatase type titanium oxide, fluorescent whitening agent, ultramarine blue to polyethylene, as is widely done in photographic paper, Those having improved whiteness and hue are preferred. Here, as a titanium oxide content, about 3-40 mass% is preferable with respect to polyethylene, and 4-30 mass% is more preferable. Although the thickness of a polyethylene layer does not have limitation in particular, 10-50 micrometers is suitable for 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. Further, the thickness of the undercoat layer is preferably 0.01 to 5 μm.

  Polyethylene-coated paper can be used as glossy paper, or matte or silky surface that can be obtained with ordinary photographic printing paper by applying a so-called molding process when polyethylene is melt-extruded and coated on the base paper surface. 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 back coat 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 backcoat layer include an antifoaming agent, an antifoaming agent, a dye, a fluorescent brightening agent, a preservative, and a water-proofing agent.

[Method for producing inkjet recording medium]
Here, the manufacturing method of the ink jet recording medium in the present invention will be described.
(Preparation of top layer coating solution and each bottom layer coating solution)
In this invention, when preparing the coating liquid containing microparticles | fine-particles and a hydrophilic binder as the uppermost-layer coating liquid and each lower-layer coating liquid, it can prepare as follows, for example. Here, “each lower layer coating solution” refers to a coating solution for forming each layer other than the uppermost layer.

  That is, fine particles such as gas phase method silica, ion exchange water, a dispersant, and a water-soluble polyvalent metal salt are mixed and dispersed by a dispersion machine described later, and then the dispersion system is set to 40 to 45 ° C. Heat and hold for 20-30 hours. Then, it prepares by adding a crosslinking agent, polyvinyl alcohol solution, cation-modified latex, and ethanol water at 28-38 degreeC. The coating solution is preferably prepared at 28 to 38 ° C. If necessary, a pH adjuster, a surfactant, an antifoaming agent, an antistatic agent, and the like can be further added to the coating solution.

As dispersion machines used for dispersion, various conventionally known dispersion machines such as a high-speed rotary dispersion machine, a medium stirring type dispersion machine (ball mill, bead mill, sand mill, etc.), an ultrasonic dispersion machine, a colloid mill dispersion machine, and a high-pressure dispersion machine are used. However, in order to efficiently disperse the generated fine particles, a medium stirring type disperser, a colloid mill disperser, or a high pressure disperser (homogenizer) is preferable.
As a disperser applied to the present invention, a medium stirring disperser such as a bead mill is mainly preferably used. From the viewpoint of promoting atomization and high Dm, a high-pressure homogenizer (for example, SUGINO MACHINE Co., Ltd.) is used. Particularly preferred is an optimizer made of the like.

  Moreover, water, an organic solvent, or these mixed solvents can be used as a solvent used for preparation of each coating liquid. Examples of organic solvents that can be used in the coating solution 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. Can be mentioned.

  The uppermost layer coating solution and each lower layer coating solution can be prepared by the same method. However, in order to achieve the effect of the present invention, an ink having a higher concentration of a cationic substance than the uppermost layer ink receiving layer. The composition of each layer is adjusted so that a receiving layer is present.

Or it may be as follows.
That is, after preparing the coating solution for each layer including the uppermost layer with the same composition, a highly polar cationic substance such as basic polyaluminum hydroxide is applied only to the lower layer coating solution excluding the uppermost layer, such as in-line mixing. By adding by means, an ink receiving layer having a higher concentration of the cationic substance than the uppermost ink receiving layer may be present. Here, the layer to which basic polyaluminum hydroxide or the like is added may be a lower layer that is in direct contact with the uppermost layer, an arbitrarily selected layer below the lower layer, or all layers except the uppermost layer. It may be.

(Formation of ink receiving layer)
The ink receiving layer in the invention can be formed by simultaneously applying (multilayer coating) the prepared coating liquid for each layer on a support by a known coating method.
Simultaneous coating (multilayer coating) can be performed by a known coating method using, for example, an extrusion die coater or a curtain flow coater.

Or you may form by apply | coating the prepared coating liquid for each layer one layer at a time with a well-known coating method.
The coating can be performed by a known coating method 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.

Or it may be as follows.
That is, a top layer coating solution containing fine particles and a hydrophilic binder (optionally a cationic material) and a lower layer coating solution containing fine particles, a hydrophilic binder and a cationic material are applied in layers and coated on a support. Form a layer. Next, a crosslinking agent is added to the coating solution and / or a basic solution having a pH of 7.1 or more, and (1) the coating solution is applied to form each coating layer, or (2) The basic solution is applied to the coating layer at any time during the drying of each coating layer formed by coating the coating solution and before the coating layer exhibits reduced-rate drying, and the coating layer It may be formed by a method of crosslinking and curing.
Here, the coating layer may be formed by coating one layer at a time in addition to the multilayer coating.

  In addition, “before the coating layer exhibits reduced-rate drying” usually refers to a process for several minutes immediately after the application of the coating liquid for the ink receiving layer. During this period, the solvent (dispersion medium) in the coated coating layer ) Shows a phenomenon of “constant rate drying” in which the content of) decreases in proportion to time. 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.

  Moreover, the said basic solution can be prepared as follows, for example. That is, a mordant (for example, 0.1 to 5.0% by mass), a surfactant (for example, 0.01 to 1.0% by mass in total) and a crosslinking agent (0 to 5.0% by mass) and sufficiently stirred. The pH of the basic solution is preferably 8.0 or more, and pH adjustment is carried out using ammonia water, sodium hydroxide, calcium hydroxide, amino group-containing compounds (ethylamine, ethanolamine, diethanolamine, polyallylamine, etc.) and the like. It can be appropriately performed at 0.0 or more.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In this embodiment, an ink jet recording sheet is prepared as an example of the ink jet recording medium. Further, “parts” and “%” in the examples represent mass standards unless otherwise specified.

[Example 1]
(Production of support)
50 parts of LBKP made of acacia and 50 parts of LBKP made of aspen were beaten to 300 ml of Canadian freeness by a disc refiner to prepare a pulp slurry.
Then, the pulp slurry obtained above was cation modified starch (CAT 0304L manufactured by NSC Japan) 1.3%, 0.15% anionic polyacrylamide (DA4104 manufactured by Seiko PMC), alkyl ketene dimer (Arakawa Chemical Co., Ltd.) per pulp. Size pine K) 29%, 0.29% epoxidized behenamide, 0.32% polyamide polyamine epichlorohydrin (Arakawa Chemical Co., Ltd .: Arafix 100) were added, and then 0.12% of an antifoaming agent was added.

In the process of making the pulp slurry prepared as described above with a long paper machine and pressing the felt surface of the web against the drum dryer cylinder through the dryer canvas for drying, the tensile force of the dryer canvas is 1.6 kg / After drying at a setting of cm, 1 g / m ² of polyvinyl alcohol (manufactured by Kuraray Co., Ltd .: KL-118) was applied to both sides of the base paper with a size press and dried to perform calendar treatment. The base paper was made with a basis weight of 166 g / m ² to obtain a base paper (base paper) having a thickness of 160 μm.

After the corona discharge treatment is performed on the wire surface (back surface) side of the obtained base paper, a high-density polyethylene is coated to a thickness of 32 g / m ² using a melt extruder, and thermoplasticity comprising a mat surface. A resin layer was formed (hereinafter, this thermoplastic resin layer surface is referred to as “back surface”). The thermoplastic resin layer on the back side is further subjected to corona discharge treatment, and then, as an antistatic agent, aluminum oxide (“Alumina Zil 100” manufactured by Nissan Chemical Industries, Ltd.) and silicon dioxide (manufactured by Nissan Chemical Industries, Ltd.) Of “Snowtex O”) was dispersed in water at a mass ratio of 1: 2 so that the dry mass was 0.2 g / m ² . Subsequently, the surface was corona-treated and coated with polyethylene having a density of 0.93 g / m ² having 10% by mass of titanium oxide using a melt extruder so as to have a density of 24 g / m ² .

An undercoat layer having the following composition was applied to the polyethylene-coated paper thus surface-treated.
An undercoat solution having the following composition was applied at 10 ml / m ² using a wire bar, and then dried at 70 ° C. for 2 minutes to obtain a support.
<Composition of undercoat liquid>
(1) Deionized alkali-treated gelatin (isoelectric point 5.0) ... 10.0 parts (2) Water ... 24.0 parts (3) Methanol ... 961.0 parts

(Preparation of ink receiving layer coating liquid A)
(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, and a bead mill ( For example, after dispersion using KD-P (manufactured by Jinmaru Enterprises Co., Ltd.), the dispersion system was heated to 45 ° C. and held for 20 hours, after which (5) boric acid and ( 6) A polyvinyl alcohol solution, (7) “Superflex 600”, and (8) ethanol water were added at 30 ° C. to prepare an ink-receiving layer coating solution A. The coating solution was prepared at 36 ° C.
(Preparation of ink receiving layer coating solution B)
After mixing (1) to (4) in the preparation of the ink-receiving layer coating liquid A, a liquid-liquid collision type disperser (Ultimizer, manufactured by Sugino Machine Co., Ltd.) is used instead of the bead mill in the preparation of the coating liquid A. Dispersion was performed at 170 MPa in one pass. Further, (8) Ink-receiving layer coating solution B was prepared in the same manner as the ink-receiving layer coating solution A except that ethanol water (ethanol content 59%) was not added.

<Composition of coating liquids A and B for ink receiving layer>
(1) Gas phase method silica fine particles: 100 parts (AEROSlL300SF75, manufactured by Nippon Aerosil Co., Ltd.)
(2) Ion-exchanged water: 557 parts (3) “Charol DC-902P”: 8.7 parts (dispersant, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., 51.5% aqueous solution)
(4) Zirconyl acetate: 1.35 parts

("ZA-30", manufactured by Daiichi Elemental Chemical Co., Ltd., 50% aqueous solution)
(5) Boric acid (crosslinking agent) aqueous solution (7.5%) ... 92.0 parts (6) Polyvinyl alcohol (hydrophilic binder) solution ... 382.0 parts-Composition of the solution-
Polyvinyl alcohol 25.7 parts ("PVA235", saponification degree 88%, polymerization degree 3500, manufactured by Kuraray Co., Ltd.)
・ Polyoxyethylene lauryl ether: 0.7 parts (“Emulgen 109P”, surfactant, manufactured by Kao Corporation)
・ Diethylene glycol monobutyl ether 6.7 parts ("Butizenol 20P", manufactured by Kyowa Hakko Co., Ltd.)
・ Ion-exchanged water: 348.9 parts (7) “Superflex 600”: 12.5 parts (cation-modified latex, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
(8) Ethanol water (ethanol content 59%) ... 15 parts

(Preparation of inkjet recording sheet)
The ink receiving layer coating solution A: 183 ml / m ² (lower layer) and the ink receiving layer coating solution A: 13.3 ml / m ² (uppermost layer) were coated on the surface of the support in a simultaneous multi-layer. At this time, the coating liquid A for the ink-receiving layer used for the lower layer was 12 times diluted basic polyaluminum hydroxide aqueous solution (basic polyaluminum hydroxide is alpha-in 83 (manufactured by Daimei Chemical Co., Ltd.)). In-line mixing was performed at a rate of 0.0 ml / m ² . All coating solutions were heated to 36 ° C. and applied.
Then, after cooling the coating solution with a wind of 10 ° C. and a relative humidity of 50%, the coating liquid was dried with a wind of 43 ° C. and a relative humidity of 7% at a wind speed of 5 to 30 m / sec for 1 to 3 minutes, and further 22 ° C. It was completely dried at a wind speed of 5 to 30 m / sec with a wind having a relative humidity of 23%. An ink jet recording sheet of Example 1 provided with an ink receiving layer having a dry film thickness of 38 μm was prepared.

[Example 2]
An ink jet recording sheet of Example 2 was produced in the same manner as in Example 1 except that the ink receiving layer coating liquid A used for forming the uppermost layer in Example 1 was changed to the ink receiving layer coating liquid B. .

[Comparative Example 1]
In Example 1, the basic polyaluminum hydroxide aqueous solution (basic polyaluminum hydroxide is alpha-in 83 (manufactured by Daimei Chemical Co., Ltd.) diluted in the ink receiving layer coating liquid A used for forming the uppermost layer. )) Was prepared in the same manner as in Example 1 except that in-line mixing was performed at a rate of 1.0 ml / m ² to produce an inkjet recording sheet of Comparative Example 1.

[Comparative Example 2]
In Example 2, a basic polyaluminum hydroxide aqueous solution (basic polyaluminum hydroxide is alpha-in 83 (manufactured by Daimei Chemical Co., Ltd.) diluted in the ink receiving layer coating liquid B used for forming the uppermost layer. The ink jet recording sheet of Comparative Example 2 was prepared in the same manner as in Example 1 except that in-line mixing was performed at a rate of 1.0 ml / m ² .

[Comparative Example 3]
In Example 2, a basic polyaluminum hydroxide aqueous solution (basic polyaluminum hydroxide is alpha-in 83 (manufactured by Daimei Chemical Industry Co., Ltd.)) was added in the same manner as in Example 2 except that no comparative example was added. No. 3 inkjet recording sheet was produced.

〔Evaluation test〕
The following evaluation tests were performed on each of the ink jet recording sheets of the examples obtained above and the ink jet recording sheets of the comparative examples. The test results are shown in Table 1 below.

(1) Black density (Bk-Dmax)
Using an inkjet printer (“PM G-800” manufactured by Seiko Epson Corporation), a black solid image was printed on each inkjet recording sheet and applied to a reflection densitometer (“Xrite 938” manufactured by Xrite). (2) Ozone resistance Using an inkjet printer (“PM G-800” manufactured by Seiko Epson Corporation), the optical density of each color is 1.0 on each inkjet recording sheet. A monochrome image was printed as follows. Thereafter, each print sample was allowed to stand for 48 hours in an ozone gas mixed air-atmosphere of 10 ppm concentration under an environmental condition of a temperature of 23 ° C. and a relative humidity of 50%. Each color image density before and after this test was measured with a reflection densitometer (“Xrite 938” manufactured by Xrite), and the residual ratio of each color density was calculated.
(3) Bronzing evaluation Each image-receiving sheet was conditioned in an environment of 35 ° C. and 80% for 16 hours, and under the same environment, using an inkjet printer (“PM G-800” manufactured by Seiko Epson Corporation) After printing the solid image, the bronzing evaluation was performed visually. In the evaluation, the case where a reddish bronze-like metallic luster was generated was evaluated as x, and the case where it was not generated was evaluated as O.

  As shown in Table 1, the ink jet recording sheets of Examples 1 and 2 did not generate bronzing and were excellent in ozone resistance. In contrast, bronzing occurred in the inkjet recording sheets of Comparative Examples 1 and 2. Further, the ink jet recording sheet of Comparative Example 3 in which basic polyaluminum hydroxide was not used for the uppermost layer and the lower layer was inferior in ozone resistance.

Claims (6)

On a support, an ink jet recording medium of the ink-receiving layer formed by forming at least two layers containing a fumed silica and parent aqueous binder, than the uppermost layer of the ink-receiving layer of the ink receiving layer An ink jet recording medium, wherein an ink receiving layer having a high mass ratio of basic polyaluminum hydroxide to vapor phase silica is present, and the uppermost layer contains a water-soluble zirconyl compound . The mass ratio of the basic polyaluminum hydroxide to the gas phase method silica in the uppermost layer is 90 % of the mass ratio of the basic polyaluminum hydroxide to the gas phase method silica in any one of the ink receiving layers other than the uppermost layer. The inkjet recording medium according to claim 1, wherein the content is% or less. The inkjet recording medium according to claim 1 or 2 primary particle size before crisis phase silica is characterized in that it is 1nm or more 30nm or less. At least one layer of the ink-receiving layer, the volume average particle diameter 0.001Myuemu～0.1Myuemu, according to claim 1 to 3, characterized in that it is formed by using a coating solution containing a cation-modified latex resin The inkjet recording medium according to any one of the above. At least one of the ink receiving layers is formed using a coating liquid containing fine particles having a dispersed particle size of 0.08 μm to 0.14 μm, and at least one other layer is formed of a dispersed particle size of 0.10 μm to 0.20 μm. the inkjet recording medium according to any one of claims 1 to 4, characterized in that the coating solution is formed by using a containing particulate. 6. The ink jet recording medium according to claim 5 , wherein the layer formed using the coating liquid containing fine particles having a dispersed particle diameter of 0.08 to 0.14 [mu] m is the uppermost layer.