JP2007160731A - Inorganic fine particle dispersion, its manufacturing method and method for manufacturing inkjet recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inorganic fine particle dispersion which can inhibit the generation of a finished product loss, a method for manufacturing the inorganic fine particle dispersion and a method for manufacturing an inkjet recording medium. <P>SOLUTION: This method for manufacturing the inorganic fine particle dispersion comprises a preliminary dispersion process to obtain a preliminary dispersion by preliminarily dispersing a mixed liquid containing a water-soluble organic cationic compound, a water-soluble polyvalent metal compound and an inorganic fine particle, and a regular dispersion process to obtain an inorganic fine particle dispersion by regularly dispersing the preliminary dispersion. In addition, this method is designed in the way that the regular dispersion is performed after retaining the preliminary dispersion at a non-freezing temperature of at most 15°C for more than two days. Further, the inorganic fine particle dispersion obtained by the method for manufacturing the inorganic fine particle dispersion and the method for manufacturing the inkjet recording medium using the inorganic fine particle dispersion are provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an inorganic fine particle dispersion, a method for producing the same, and a method for producing an ink jet recording medium.

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

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

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

For example, an inkjet recording sheet is proposed in which an ink receiving layer containing fine inorganic pigment particles and a water-soluble resin and having a high porosity is provided on a support (see, for example, Patent Document 1 or 2). ).
These recording sheets, particularly ink jet recording sheets provided with an ink receiving layer having a porous structure using silica as inorganic pigment fine particles, are excellent in ink absorptivity and can form high resolution images. It is said that it has high ink receiving performance and can exhibit high gloss.

The method for producing an ink jet recording sheet is usually as follows. First, inorganic fine particles such as silica are dispersed in an aqueous medium through a preliminary dispersion step and a main dispersion step to obtain a dispersion. After heat-treating the obtained dispersion, polyvinyl alcohol and other chemicals are mixed to prepare an ink-receiving layer coating solution. An ink jet recording sheet is produced by applying a coating liquid for an ink receiving layer onto a support and drying.
JP 10-119423 A Japanese Patent Laid-Open No. 10-217601

When the ink receiving layer coating liquid is applied on the support, the coating liquid swells at the end of the coating liquid. When the swell is large, stress is applied to the end portion of the wound ink-jet recording sheet, and the portion is cracked. The part where the crack occurs is a product loss. Further, when the bulge is large, the portion becomes undried, and when the ink jet recording sheet is wound in the undried state, adhesion occurs in the undried portion. When the wound inkjet recording sheet is subjected to a subsequent process, the support may be torn when the adhesive part is peeled off, which may cause problems such as stoppage of a processing machine and occurrence of product loss in the subsequent process.
The present invention has been made in view of the above problems, and an inorganic fine particle dispersion capable of suppressing the occurrence of product loss without deteriorating the printing density, a method for producing the same, and an ink jet recording medium using the inorganic fine particle dispersion It aims at providing the manufacturing method of.

That is, the present invention
<1> A preliminary dispersion step of preliminarily dispersing a mixed liquid containing a water-soluble organic cation compound, a water-soluble polyvalent metal compound and inorganic fine particles to obtain a preliminary dispersion; And an inorganic fine particle dispersion in which the main dispersion is performed after the preliminary dispersion is held at a temperature of not more than 15 ° C. for 2 days or more. It is a manufacturing method of a liquid.

  <2> The method for producing an inorganic fine particle dispersion according to <1>, wherein an average primary particle diameter of the inorganic fine particles is 30 nm or less, and a volume average particle diameter of the inorganic fine particles in the inorganic fine particle dispersion is 200 nm or less.

  <3> The method for producing an inorganic fine particle dispersion according to <1> or <2>, wherein the inorganic fine particles are vapor phase silica.

<4> The method for producing an inorganic fine particle dispersion according to any one of <1> to <3>, wherein a specific surface area of the inorganic fine particles by BET method is 200 m ² / g or more.

  <5> The method for producing an inorganic fine particle dispersion liquid according to any one of <1> to <4>, wherein the water-soluble polyvalent metal compound is a trivalent or higher metal compound.

  <6> The method for producing an inorganic fine particle dispersion according to <5>, wherein the trivalent or higher-valent metal compound is an aluminum compound and / or a zirconium compound.

  <7> The method for producing an inorganic fine particle dispersion according to <6>, wherein the aluminum compound is basic polyaluminum hydroxide.

  <8> The method for producing an inorganic fine particle dispersion according to <6>, wherein the zirconium compound is zirconyl acetate or ammonium zirconium carbonate.

  <9> The inorganic fine particle dispersion according to any one of <1> to <8>, wherein the water-soluble organic cation compound is a compound having a primary to tertiary amino group, a quaternary ammonium base, or a phosphonium base. It is a manufacturing method of a liquid.

  <10> An inorganic fine particle dispersion produced by the method for producing an inorganic fine particle dispersion according to any one of <1> to <9>.

  <11> A method for producing an ink jet recording medium comprising a coating step of coating an ink receiving layer coating liquid containing the inorganic fine particle dispersion liquid according to <10> on a support.

  ADVANTAGE OF THE INVENTION According to this invention, the inorganic fine particle dispersion which can suppress generation | occurrence | production of a product loss, its manufacturing method, and the manufacturing method of an inkjet recording medium using this inorganic fine particle dispersion are provided.

Hereinafter, the inorganic fine particle dispersion of the present invention, a method for producing the same, and a method for producing an ink jet recording medium using the inorganic fine particle dispersion will be described in detail.
The method for producing an inorganic fine particle dispersion of the present invention comprises a preliminary dispersion step of preliminarily dispersing a mixed liquid containing a water-soluble organic cation compound, a water-soluble polyvalent metal compound and inorganic fine particles to obtain a preliminary dispersion, and the preliminary dispersion And a main dispersion step for obtaining a dispersion of inorganic fine particles, and the main dispersion is carried out after the preliminary dispersion is kept at a temperature of 15 ° C. or less at a non-freezing temperature for 2 days or more. .
Further, the method for producing an ink jet recording medium of the present invention includes a coating step of coating a coating liquid for an ink receiving layer containing the inorganic fine particle dispersion produced by the method for producing an inorganic fine particle dispersion of the present invention on a support. Is.

  When the ink receiving layer coating liquid containing the inorganic fine particle dispersion obtained by the production method of the present invention is coated on a support, it is possible to suppress the bulge of the end of the coating liquid. As a result, product loss can be suppressed.

In the present invention, the term “preliminary dispersion” refers to a treatment in which inorganic fine particles are simply adapted to a dispersion medium such as water, and the inorganic fine particles are floated or aggregated in the preliminary dispersion obtained by the preliminary dispersion. A process that disperses to the extent that there is no such phenomenon as.
The “main dispersion” means that the pre-dispersion is treated with a disperser, and the liquid after the main dispersion is measured with a particle size measuring device (for example, LA920 manufactured by HORIBA Co., Ltd.). Dispersion means that the ratio of coarse particles having a diameter of 5 μm or more is 5% or less.

In the present invention, if the holding temperature of the preliminary dispersion is higher than 15 ° C., the color developability of the printed portion may be inferior when finished into a coated product. The holding temperature of the preliminary dispersion is preferably 10 ° C. or lower.
In addition, when the preliminary dispersion is frozen, it is necessary to further dissolve the frozen preliminary dispersion when performing the main dispersion using the preliminary dispersion. Therefore, it is necessary to hold the preliminary dispersion at a temperature that does not freeze. . Specifically, the holding temperature of the preliminary dispersion is preferably 5 ° C. or higher.

If the pre-dispersion holding period is less than 2 days, thick coating at the end (width direction) becomes large at the time of application, wrinkles are generated by winding, or it becomes undried and causes adhesion failure, resulting in increased loss. Sometimes.
The retention period of the preliminary dispersion is preferably 3 days or longer. In addition, the storage period of the preliminary dispersion is preferably 30 days or less, because long-term storage may cause a problem that the liquid will rot and clog the filter in the filtration step.

  Next, each component used in the inorganic fine particle dispersion of the present invention and the production method thereof will be described.

-Inorganic fine particles-
The inorganic fine particles used in the present invention include synthetic silica, alumina hydrate, calcium carbonate, barium sulfate and the like, and are not particularly limited, but among these, synthetic silica is preferably used, and Silica fine particles synthesized by the phase method (gas phase method silica) are preferred.
Inorganic fine particles in the present invention preferably has a BET specific surface area is 200 meters ² / g or more, more preferably at least ^{250m 2 / g, 270m 2 /} g or more is particularly preferable. The upper limit of the specific surface area by the BET method is preferably 400 m ² / g or less.

The ink receiving layer has a porous structure by containing vapor-phase silica as inorganic fine particles, and the silica particles have a small particle size with a specific surface area of 200 m ² / g or more by the BET method. In this case, the ink absorbability and the print density can be further improved.

  Synthetic silica is classified into a wet process and a gas phase process, but usually silica fine particles often refer to wet process silica. Wet silicas include (1) silica sol obtained through metathesis with sodium silicate acid and ion exchange resin layer, or (2) colloidal silica obtained by heating and aging this silica sol, and (3) gelation of silica sol. And by changing the production conditions, silica gel in which primary particles of several to 10 microns become three-dimensional secondary particles having siloxane bonds, and (4) silica sol, sodium silicate, sodium aluminate, etc. There are synthetic silicic acid compounds mainly composed of silicic acid, such as those obtained by heating to form a silicic acid.

  On the other hand, gas phase method silica is also called a dry method as opposed to a wet method, and is generally made by a flame hydrolysis method. Specifically, a method of making silicon tetrachloride by burning with hydrogen and oxygen is generally known, but silanes such as methyltrichlorosilane and trichlorosilane can be used alone or silicon tetrachloride instead of silicon tetrachloride. Can be used in a mixed state. Vapor phase silica is commercially available as Aerosil from Nippon Aerosil Co., Ltd., and QS type from Tokuyama Co., Ltd., and can be obtained.

  In the ink jet recording medium of the present invention, gas phase method silica is more preferable than wet method silica because it can easily form a three-dimensional structure having a high porosity. The reason for this is not clear, but it is thought that the density of the surface silanol groups has an effect. That is, gas phase method silica has a lower density of surface silanol groups than wet method silica, and thus is considered to have a rough soft agglomeration and a structure with a high porosity. Increasing the porosity of the ink receiving layer is extremely important in terms of increasing the ink absorption rate and absorption capacity.

  The BET method referred to in the present invention is one of powder surface area measurement methods by vapor phase adsorption, and is a method for determining the total surface area, that is, the specific surface area of a 1 g sample from the adsorption isotherm. Usually, nitrogen gas is often used as the adsorbed gas, and the most frequently used method is to measure the amount of adsorption from the change in pressure or volume of the gas to be adsorbed. The most prominent expression for expressing the isotherm of multimolecular adsorption is the Brunauer, Emmett, and Teller equation, called the BET equation, which is widely used for determining the surface area. The adsorption amount is obtained based on the BET equation, and the surface area is obtained by multiplying the area occupied by one adsorbed molecule on the surface.

  Vapor phase silica has a particularly large specific surface area, so it has high ink absorption and retention efficiency, and low refractive index, so it provides transparency to the ink receiving layer when dispersed to an appropriate particle size. And high color density and good color development can be obtained. The transparency of the ink receiving layer is important from the viewpoint of obtaining a high color density and good color development gloss even when applied to uses such as photo glossy paper.

The average primary particle size of the inorganic fine particles is preferably 30 nm or less, more preferably 20 nm or less, further preferably 10 nm or less, and particularly preferably 3 to 10 nm. The average primary particle size of the inorganic fine particles is 30 nm or less, and the volume average particle size of the inorganic fine particles in the inorganic fine particle dispersion after the main dispersion is preferably 200 nm or less from the viewpoint of imparting gloss, and the inorganic fine particle dispersion The volume average particle diameter of the inorganic fine particles therein is more preferably 150 nm or less, and particularly preferably 120 nm or less.
Vapor phase silica is easy to adhere to each other by hydrogen bonds with silanol groups, so it can form a structure with a large porosity when the average primary particle size is 30 nm or less, effectively improving ink absorption characteristics. In addition, the transparency and surface gloss of the ink receiving layer can be enhanced. In addition, the vapor phase method silica may be used as primary particles or may be contained in a state where secondary particles are formed.

  The total content (solid content) of the vapor phase silica (and other inorganic fine particles if necessary) in the ink receiving layer is preferably 60% by mass or more, and more preferably 65% by mass or more. When the total content is 60% by mass or more, a more favorable porous structure can be formed, and an ink jet recording medium having sufficient ink absorbability can be obtained. Here, the amount (solid content) in the ink receiving layer is an amount calculated based on components other than water in the composition constituting the ink receiving layer.

  Other inorganic fine particles can be used in combination with the vapor phase silica. Other inorganic fine particles include, for example, other silica fine particles, colloidal silica, titanium dioxide, barium sulfate, calcium silicate, zeolite, kaolinite, halloysite, mica, talc, calcium carbonate, magnesium carbonate, calcium sulfate, zinc oxide, water Examples thereof include zinc oxide, alumina, aluminum silicate, calcium silicate, magnesium silicate, zirconium oxide, zirconium hydroxide, cerium oxide, lanthanum oxide, and yttrium oxide. These fine particles can be contained in the form of primary particles or secondary particles, and the average primary particle diameter is preferably 20 μm or less, more preferably 200 nm or less.

  When the vapor phase silica (and other inorganic fine particles if necessary) is used for an ink jet recording medium, for example, JP-A Nos. 10-81064, 10-119423, 10-157277, 10-217601, 11-348409, JP-A-2001-138621, JP-A-2000-431401, JP-A-2000-21235, JP-A-2000-309157, JP-A-2001-968627, JP-A-2001-138627, JP-A-11-91242, Also preferred are the embodiments disclosed in JP-A Nos. 8-2087, 8-2090, 8-2091, 8-2093, 8-174992, 11-192777, JP-A-2001-301314, etc. Can be used.

  Further, for the purpose of improving the dispersibility, the surface of the fine particles of the vapor phase method silica may be treated with a silane coupling agent. As the silane coupling agent, an organic functional group (for example, a vinyl group, an amino group, an epoxy group, a mercapto group, a chloro group, an alkyl group, a phenyl group, an ester group, etc.) in addition to the site where the coupling treatment is performed. What has is preferable.

-Water-soluble organic cation compound-
The water-soluble organic cation compound is used as a dispersant (aggregation inhibitor) for inorganic fine particles.
Examples of the water-soluble organic cation compound used in the present invention include compounds having primary to tertiary amino groups, quaternary ammonium bases, or phosphonium bases (including salts thereof) such as examples of mordants described later. Is preferred. Among them, the average molecular weight is preferably 50,000 or less, and particularly preferably 20,000 or less. A silane coupling agent can be used as the other dispersant.

  Among the water-soluble organic cation compounds, a water-soluble organic cation compound having a structural unit of a polydiallylamine derivative is particularly preferable, and obtained by cyclization condensation of a diallylamine compound, Charol DC902P (Daiichi Kogyo Seiyaku Co., Ltd.), Jetfix 110 (Satota) Chemical), Unisense CP-101 to 103 (Senka), and PAS-H (Nitto Boseki).

The amount of the water-soluble organic cation compound used is preferably 1 to 10% by mass and more preferably 1 to 5% by mass with respect to inorganic fine particles (for example, silica fine particles). When the amount used is increased, the gelation ability after coating decreases depending on the type of vapor phase silica used.
As the water-soluble organic cation compound, a water-soluble or aqueous emulsion type or the like can be suitably used. system cationic resin, epichlorohydrin - dimethylamine addition polymers, dimethyldiallylammonium chloride -SO ₂ copolymer, diallylamine salt -SO ₂ copolymer, dimethyl diallyl ammonium chloride polymer, polymer of allylamine salt, dialkylaminoethyl (meth ) Polycationic cationic resins such as acrylate quaternary salt polymers and acrylamide-diallylamine salt copolymers. Of these, dimethyldiallylammonium chloride, monomethyldiallylammonium chloride and polyamidine are preferred, and dimethyldiallylammonium chloride and monomethylammonium chloride are particularly preferred from the viewpoint of water resistance. The water-soluble organic cation compound may be used alone or in combination of two or more.

  The addition amount of the water-soluble organic cation compound in the ink receiving layer is preferably 1 to 10% by mass, and more preferably 1 to 5% by mass with respect to the mass of the vapor phase silica.

  The water-soluble organic cation compound may be added to the dispersion medium before the addition of the inorganic fine particles, or may be added during the premixing or after the completion of the dispersion. It is preferable to add to the dispersion medium before adding.

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

  Among the above water-soluble polyvalent metal compounds, an aluminum compound or a compound composed of a Group 4A metal (for example, zirconium or titanium) in the periodic table is preferable. More preferred are aluminum compounds and / or zirconium compounds. Particularly preferred is a water-soluble aluminum compound. As a water-soluble aluminum compound, for example, as an inorganic salt, aluminum chloride or a hydrate thereof, aluminum sulfate or a hydrate thereof, ammonium alum and the like are known. Furthermore, basic polyaluminum hydroxide which is an inorganic aluminum-containing cationic polymer is known and preferably used.

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

[Al ₂ (OH) _n Cl _6-n ] _m 1 <m <10, 0 <n <60 Formula 1
[Al (OH) ₃ ] _n AlCl ₃ 0 <n <20 Formula 2
Al _n (OH) _m Cl _(3n-m) 0 <m <3n Formula 3

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

  As the water-soluble compound containing the Group 4A element of the periodic table, a water-soluble compound containing titanium or zirconium is more preferable. Examples of the water-soluble compound (titanium compound) containing titanium include titanium chloride and titanium sulfate. Examples of water-soluble compounds containing zirconium (zirconium compounds) include zirconium acetate, zirconium chloride, zirconium oxychloride, hydroxy zirconium chloride, zirconium nitrate, basic zirconium carbonate, zirconium hydroxide, zirconium lactate, ammonium zirconium carbonate, potassium zirconium carbonate, Examples thereof include zirconium sulfate and a zirconium fluoride compound. Preferred zirconium compounds include zirconium acetate or ammonium zirconium carbonate.

  The above-mentioned water-soluble polyvalent metal compound is preferably added at a ratio of 0.1 to 10% by mass, more preferably 0.5 to 8% by mass with respect to the inorganic fine particles. The concentration of the inorganic fine particles in the dispersion is suitably about 10 to 40% by mass, and preferably 15 to 35% by mass.

  The dispersion medium used in the inorganic fine particle (for example, silica fine particle) dispersion of the present invention is mainly composed of water, but may contain a small amount of an organic solvent (a low-boiling solvent such as lower alcohol or ethyl acetate). . In that case, the organic solvent is preferably 20% by mass or less, more preferably 10% by mass or less, based on the total dispersion medium.

Next, each process of the manufacturing method of the inorganic fine particle dispersion of the present invention will be described.
-Pre-dispersion process-
In the preliminary dispersion step, a preliminary dispersion can be obtained by adding, mixing, and dispersing inorganic fine particles, a water-soluble organic cation compound, and a water-soluble polyvalent metal compound to a dispersion medium such as water. Examples of the dispersing device used for the preliminary dispersion include propeller stirring, turbine stirring, homomixer stirring, ultrasonic stirring, and the like. Any device can be used as long as it can be uniformly dispersed.

Although the liquid temperature at the time of preliminary dispersion is not particularly specified, it is preferably 30 ° C. or less, particularly preferably 25 ° C. or less. Thereby, the slurry can be stably produced. In this case, the dispersion medium before adding the inorganic fine particles may be kept at a temperature of 20 ° C. or lower, or may be cooled to 20 ° C. or lower during the premixing.
Moreover, it is preferable to inject | pour into a disperser in the state whose temperature of a slurry is 20 degrees C or less, Furthermore, 15 degrees C or less. This provides a more stable dispersion.

-This dispersion process-
The preliminary dispersion obtained through the preliminary dispersion process is held at the above-mentioned predetermined temperature for a predetermined period and then dispersed. The dispersion apparatus used for the present dispersion is not particularly limited, and for example, an opposed collision type high pressure disperser, an orifice passing type high pressure disperser, or the like can be used.

As the opposed collision type high pressure disperser or the orifice passing type high pressure disperser, a commercially available device generally called a high pressure homogenizer can be preferably used.
Typical examples of the high-pressure homogenizer include a nanomizer product name; Nanomizer (LA-31), a microfluidics product name; a microfluidizer, and a Sugino Machine optimizer.

  The orifice refers to a mechanism that inserts a thin plate (orifice plate) having a fine hole such as a circle into the straight pipe to rapidly narrow the flow path of the straight pipe.

  The high-pressure homogenizer is basically an apparatus that includes a high-pressure generating section that pressurizes raw material slurry and the like, and an opposing collision section or an orifice section. As the high-pressure generating unit, a high-pressure pump generally called a plunger pump is preferably employed. There are various types of high-pressure pumps such as a series type, a double type, and a triple type, and any type can be adopted in the present invention without any particular limitation.

The processing pressure in the case of opposing collision at high pressure is preferably 50 MPa or more, 100 MPa or more, and more preferably 130 MPa or more.
Also, the differential pressure between the inlet side and the outlet side of the orifice when passing through the orifice is 50 MPa or more, preferably 100 MPa or more, more preferably 130 MPa or more, like the processing pressure. Each is preferably 350 MPa or less.

  In any method, since the dispersion efficiency depends on the processing pressure, the higher the processing pressure, the higher the dispersion efficiency. However, if the treatment pressure exceeds 350 MPa, problems are likely to occur in the pressure resistance of the piping of the high-pressure pump and the durability of the apparatus.

  In any of the methods described above, the number of treatments is not particularly limited, and is usually appropriately selected from a range of 1 to several tens of times. Thereby, the inorganic fine particle dispersion of the present invention can be obtained.

In preparing the inorganic fine particle dispersion of the present invention, various additives can be added.
Examples of additives include various nonionic or cationic surfactants (anionic surfactants are not preferred for forming aggregates), antifoaming agents, nonionic hydrophilic polymers (polyvinyl alcohol, Polyvinyl pyrrolidone, polyethylene oxide, polyacrylamide, various sugars, gelatin, pullulan, etc., nonionic or cationic latex dispersion, water-miscible organic solvent (ethyl acetate, methanol, ethanol, isopropanol, n-propanol, acetone, etc.) ), Inorganic salts, pH adjusters and the like, and these can be used as needed.

  In particular, a water-miscible organic solvent is preferable in that formation of fine lumps when inorganic fine particles (silica), a water-soluble organic cation compound, and a water-soluble polyvalent metal compound are predispersed is suppressed. The water-miscible organic solvent is used in the dispersion in an amount of 0.1 to 20% by mass, particularly preferably 0.5 to 10% by mass.

  The pH at the time of preparing the inorganic fine particle (gas phase method silica) dispersion can vary widely depending on the type of inorganic fine particle (gas phase method silica), the type of water-soluble organic cation compound, various additives, etc. Generally, pH is 1-8, and 2-7 are especially preferable. In addition, two or more of the above additives can be used in combination.

The ink jet recording medium produced by the production method of the present invention comprises an ink receiving layer on a support. The ink receiving layer is formed by applying an ink receiving layer coating solution onto a support.
The ink receiving layer coating liquid includes the above-described inorganic fine particle dispersion of the present invention, a water-soluble resin (hydrophilic binder) such as polyvinyl alcohol as necessary, a cross-linking agent that cross-links the water-soluble resin, and a surfactant. It can be obtained by mixing a water-dispersible cationic resin or the like. Below, each component used for the coating liquid for ink receiving layers is demonstrated.

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

  The water-soluble resin is not particularly limited, but among the above, from the viewpoint of layer transparency and coating formability, the type of the water-soluble resin to be combined with the gas phase method silica is important. Resins are preferred. Examples of the polyvinyl alcohol resin include Japanese Patent Publication No. 4-52786, Japanese Patent Publication No. 5-67432, Japanese Patent Publication No. 7-29479, Japanese Patent No. 2537827, Japanese Patent Publication No. 7-57553, Japanese Patent No. 2502998, and Japanese Patent No. 2502998. 3053231, JP 63-176173, JP 2604367, JP 7-276787, JP 9-207425, JP 11-58941, JP 2000-135858, JP 2001-205924. JP-A-2001-287444, JP-A-62-278080, JP-A-9-39373, JP-A-2750433, JP-A-2000-158801, JP-A-2001-213045, JP-A-2001-328345, Those described in Kaihei 8-324105, JP-A-11-348417, etc. It is below. Examples of water-soluble resins other than polyvinyl alcohol resins include compounds described in JP-A No. 11-165461, [0011] to [0014]. The above water-soluble resins may be used alone or in combination of two or more.

  The polyvinyl alcohol-based resin has a hydroxyl group in its structural unit, and since this hydroxyl group and the surface silanol group of the gas phase method silica form a hydrogen bond, a three-dimensional structure in which secondary particles of silica fine particles are network chain units. It becomes easy to form a network structure. By forming this three-dimensional network structure, it is considered that an ink receiving layer having a porous structure with a high porosity and sufficient strength can be formed. As described above, the porous ink receiving layer can absorb ink rapidly by capillary action, and can form dots with good roundness without ink bleeding.

The water-soluble resin may be used alone or in combination of two or more. The content of the water-soluble resin in the ink receiving layer is preferably 9 to 40% by mass, and more preferably 12 to 33% by mass with respect to the solid content (mass) of the layer. In addition, the other water-soluble resin may be used together with the polyvinyl alcohol resin, and the amount of the polyvinyl alcohol resin in the total water-soluble resin when used in combination is preferably 50% by mass or more, and 70% by mass. % Or more is more preferable.
Examples of the water-soluble resin include celluloses such as polyvinyl alcohol, polyvinyl pyrrolidone, and carboxymethyl cellulose, gelatin, and the like, preferably polyvinyl alcohol. Among polyvinyl alcohols, those having a saponification degree of 80% or more or those completely saponified are preferable. Polyvinyl alcohol having an average degree of polymerization of 500 to 5000 is preferred. Examples of the cation-modified polyvinyl alcohol include primary to tertiary amino groups and quaternary ammonium groups in the main chain or side chain of polyvinyl alcohol as described in, for example, JP-A-61-10383. And polyvinyl alcohol.

<Content ratio of gas phase method silica and water-soluble resin>
The mass content ratio [PB ratio (x / y)] of the vapor phase method silica (x) and the water-soluble resin (y) greatly affects the film structure and film strength of the ink receiving layer. That is, as the mass content ratio [PB ratio] increases, the porosity, pore volume, and surface area (per unit mass) increase, but the density and strength tend to decrease. At least the ink receiving layer according to the present invention, as the PB ratio (x / y), prevents a decrease in film strength and cracking during drying due to the PB ratio being too large, and the PB ratio is too small. From the viewpoint of preventing the gap from being easily blocked by the resin and preventing the ink absorbency from being lowered due to a decrease in the porosity, 1.5 to 10 is preferable. The addition amount of the water-soluble resin is preferably in the range of 5 to 40% by mass, more preferably in the range of 10 to 25% by mass with respect to the inorganic fine particles.

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

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

(Crosslinking agent)
The ink receiving layer according to the present invention contains a crosslinking agent. That is, when the ink receiving layer contains a crosslinking agent capable of crosslinking the water-soluble resin, the ink receiving layer can be a porous layer cured by a crosslinking reaction between the crosslinking agent and the water-soluble resin.

Boron compounds are preferred for crosslinking the above water-soluble resins, particularly polyvinyl alcohol resins. Examples of the boron compound include borax, boric acid, borates (for example, orthoborate, InBO ₃ , ScBO ₃ , YBO ₃ , LaBO ₃ , Mg ₃ (BO ₃ ) ₂ , Co ₃ (BO ₃ ) ₂ , two Borate (eg, Mg ₂ B ₂ O ₅ , Co ₂ B ₂ O ₅ ), metaborate (eg, LiBO ₂ , Ca (BO ₂ ) ₂ , NaBO ₂ , KBO ₂ ), tetraborate (eg, Na _{2 B 4 O 7 · 10H 2} O), 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. Among them, Of these, borax, boric acid and borates are preferable, and boric acid is particularly preferable because a crosslinking reaction can be promptly caused.
Other specific examples of the crosslinking agent include aldehyde compounds such as formaldehyde and glutaraldehyde, ketone compounds such as diacetyl and chloropentanedione, and reactive halogens as described in US Pat. No. 3,288,775. Compound, divinyl sulfone, compound having reactive olefin as described in US Pat. No. 3,635,718, N-methylol compound as described in US Pat. No. 2,732,316, US Pat. No. 3,103,437 Isocyanates such as those described in US Pat. No. 3,017,280 and 2,983,611, carbodiimide compounds such as those described in US Pat. No. 3,100,704, Epoxy compounds as described in Japanese Patent No. 3,091,537, halogen carbo such as mucochloric acid Shi aldehydes, such as dioxane derivatives of dihydroxy dioxane, chromium alum, there are inorganic hardeners such as such as zirconium sulfate, boric acid and borates can be used in combination thereof one or more.

  Further, for example, aldehyde compounds such as glyoxal and glutaraldehyde; ketone compounds such as cyclopentanedione; bis (2-chloroethylurea) -2-hydroxy-4,6-dichloro-1,3,5-triazine, Active halogen compounds such as 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 (eg, 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 compounds such as dioxane; Titanium lactate, aluminum sulfate, chromium alum, potash alum, metal-containing compounds such as zirconyl acetate and chromium acetate, polyamine compounds such as tetraethylenepentamine, and hydrazide compounds such as adipic acid dihydrazide It is a small molecule or polymer or the like containing an oxazoline group two or more. The above crosslinking agents may be used singly or in combination of two or more.

  The cross-linking agent may be added to the ink-receiving layer coating liquid and / or the coating liquid for forming an adjacent layer of the ink-receiving layer when the ink-receiving layer coating liquid is applied. The coating liquid for the ink-receiving layer is coated on the support coated with the coating liquid containing, the coating liquid for the ink-receiving layer containing no cross-linking agent is applied, and the cross-linking agent solution is overcoated after drying. A crosslinking agent can be supplied to the ink receiving layer.

  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 coating liquid A for the ink receiving layer, crosslinking curing is performed simultaneously with (1) forming the coating layer by coating the coating liquid A. (2) A basic solution having a pH of 7.1 or higher (solution) during the dry coating of the coating layer formed by coating the coating liquid A and before the coating layer exhibits reduced-rate drying B) is applied to the coating layer. The boron compound as a crosslinking agent may be contained in either the coating solution A or the solution B, and may be contained in both the coating solution A and the solution B. When the ink receiving layer is composed of two or more layers, two or more coating liquids can be applied in multiple layers, and a basic solution (solution B) may be applied from the layer formed.

  0.01-50 mass% is preferable with respect to the mass of the water-soluble resin in a layer, and, as for the usage-amount of a crosslinking agent, 5-40 mass% is more preferable.

(Water-dispersible cationic resin)
Examples of the water-dispersible cationic resin include urethane resins, acrylic resins, styryl resins, butadiene resins, and the like, and are preferably urethane resins that are cationically modified self-emulsifying polymers and have a glass transition temperature. Is preferably less than 50 ° C.
This “cation-modified self-emulsifying polymer” means a highly stable emulsified dispersion that can be naturally stabilized in an aqueous dispersion medium without using an emulsifier or a surfactant, or even if used in a very small amount. Means a molecular compound. Quantitatively, the “cation-modified self-emulsifying polymer” means a polymer substance having stable emulsification and dispersion at a concentration of 0.5% by mass or more with respect to the aqueous dispersion medium at room temperature of 25 ° C. The concentration is preferably 1% by mass or more, and more preferably 3% by mass or more.

  More specifically, the “cation-modified self-emulsifying polymer” of the present invention is, for example, a polyaddition system or polycondensation having a cationic group such as a primary to tertiary amino group or a quaternary ammonium group. -Based polymer compounds (cationic group-containing polymers).

Examples of the vinyl polymerization polymer effective as the polymer include a polymer obtained by polymerizing the following vinyl monomer and a monomer having a cationic group.
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 cationic group-containing polymer include polyurethanes synthesized by 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 Luhon etc. are mentioned.

  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.

Cationic groups contained in the cationic group-containing polyurethane include cationic groups such as primary to tertiary amines and quaternary ammonium salts. The self-emulsifying polymer used in the aqueous dispersion of the present invention is preferably a urethane resin having a cationic group such as a tertiary amine and a quaternary ammonium salt.
The cationic group-containing polyurethane can be obtained, for example, by using a product obtained by introducing a cationic group into a diol 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.

(Other ingredients)
-Mordant-
The ink receiving layer according to the present invention preferably contains the following mordant for the purpose of further improving the bleeding and water resistance of the image. As the mordant, an organic mordant such as a cationic polymer (cationic mordant) and an inorganic mordant such as a water-soluble metal compound are preferable. As the cationic mordant, a polymer mordant having a primary to tertiary amino group or a quaternary ammonium base as a cationic functional group is preferably used, but a cationic non-polymer mordant should also be used. Can do.

  Examples of the polymer mordant include a homopolymer of a monomer having a primary to tertiary amino group and a salt thereof, or a quaternary ammonium base (a mordant monomer), and the mordant monomer and other monomers ( Those obtained as copolymers or condensation polymers with non-mordant monomers) are preferred. Moreover, these polymer mordants can be used in any form of a water-soluble polymer or water-dispersible latex particles.

  Examples of the mordant monomer include trimethyl-p-vinylbenzylammonium chloride, trimethyl-m-vinylbenzylammonium chloride, triethyl-p-vinylbenzylammonium chloride, triethyl-m-vinylbenzylammonium chloride, N, N-dimethyl- N-ethyl-Np-vinylbenzylammonium chloride, N, N-diethyl-N-methyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-Nn-propyl-Np-vinylbenzyl Ammonium chloride, N, N-dimethyl-Nn-octyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N-benzyl-Np-vinylbenzylammonium chloride, N, N-diethyl-N Benzyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N- (4-methyl) benzyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N-phenyl-Np-vinyl Benzylammonium chloride;

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

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

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

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

  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 interact with a dye in an inkjet ink. Or a monomer having a substantially small interaction. For example, (meth) acrylic acid alkyl ester; (meth) acrylic acid cycloalkyl ester such as cyclohexyl (meth) acrylic acid; (meth) acrylic acid aryl ester such as phenyl (meth) acrylate; benzyl (meth) acrylic acid Aralkyl esters of styrene; vinyl aromatics such as styrene, vinyl toluene and α-methyl styrene; vinyl esters such as vinyl acetate, vinyl propionate and vinyl versatate; allyl esters such as allyl acetate; vinylidene chloride, vinyl chloride, etc. Halogen-containing monomers, vinyl cyanides such as (meth) acrylonitrile, olefins such as ethylene and propylene, and the like.

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

Further, as the polymer mordant, polydiallyldimethylammonium chloride, polymethacryloyloxyethyl-β-hydroxyethyldimethylammonium chloride, polyethyleneimine, polyamide-polyamine resin, cationized starch, dicyandiamide formalin condensate, dimethyl-2-hydroxypropylammonium Salt polymer, polyamidine, polyvinylamine, dicyan diamide-formalin polycondensate represented by dicyan chaotic resin, dicyanamide-diethylene triamine polycondensate represented by polyamine chaotic resin, epichlorohydrin-dimethylamine addition polymer, dimethyl diallylammonium chloride -SO ₂ copolymer, it is mentioned as such also preferable diallylamine salt -SO ₂ copolymer Kill.

  Specific examples of the polymer mordant include JP-A Nos. 48-28325, 54-74430, 54-124726, 55-22766, 55-142339, 60-23850, and 60. -23851, 60-23852, 60-23853, 60-57836, 60-60643, 60-118834, 60-122940, 60-122941, 60-122294 No. 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, 4,273,853, JP 4282305, JP 4450224, JP-A-1-16123. 10-81064, 10-119423, 10-157277, 10-217601, 11-348409, JP-A-2001-138621, 2000-43401, 2000-212235 2000-309157, 2001-96897, 2001-138627, JP-A-11-91242, 8-2087, 8-2090, 8-2091, 8-2093, Examples described in JP-A-8-174992, JP-A-11-192777, JP-A-2001-301314, and the like.

  Examples of the inorganic mordant include polyvalent water-soluble metal salts and hydrophobic metal salt compounds other than those described above. For example, magnesium, aluminum, calcium, scandium, titanium, vanadium, manganese, iron, nickel, copper, zinc, gallium, germanium, strontium, yttrium, zirconium, molybdenum, indium, barium, lanthanum, cerium, praseodymium, neodymium, samarium, Examples include salts or complexes of metals selected from europium, gadolinium, dysproprosium, erbium, ytterbium, hafnium, tungsten, bismuth.

  Specific examples include 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, chloride chloride Dicopper, ammonium copper (II) chloride dihydrate, copper sulfate, cobalt chloride, cobalt thiocyanate, cobalt sulfate, nickel sulfate hexahydrate, nickel chloride hexahydrate, nickel acetate tetrahydrate, nickel sulfate Ammonium hexahydrate, nickel amidosulfate tetrahydrate, alumina sulfate, alumina alum, basic polyaluminum hydroxide, sulfite alumina, thiosulfate alumina, polychlorinated alumina, alumina nitrate nonahydrate, alumina chloride hexahydrate , Ferrous bromide, ferrous chloride, ferric chloride, ferrous sulfate, ferric sulfate, pheno Zinc sulfonate, zinc bromide, zinc chloride, zinc nitrate hexahydrate, zinc sulfate, titanium tetrachloride, tetraisopropyl titanate, titanium acetylacetonate, titanium lactate, zirconium acetylacetonate, zirconyl acetate, zirconyl sulfate, zirconium carbonate Ammonium, zirconyl stearate, zirconyl octylate, zirconyl nitrate, zirconium oxychloride, zirconium hydroxychloride, 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, potassium nitrate, manganese acetate, germanium nitrate Strontium nitrate, yttrium acetate, yttrium chloride, yttrium nitrate, indium nitrate, lanthanum nitrate, lanthanum chloride lanthanum acetate, lanthanum benzoate, cerium chloride, cerium sulfate, cerium octylate, praseodymium nitrate, neodymium nitrate, samarium nitrate, europium nitrate , Gadolinium nitrate, dysprosium nitrate, erbium nitrate, ytterbium nitrate, hafnium chloride, bismuth nitrate, and the like. Among these, alumina-containing compounds, titanium-containing compounds, zirconium-containing compounds, and group IIIB series metal compounds (salts or complexes) are preferable.

The addition amount when the mordant is added to the ink receiving layer is preferably 0.01 to 5 g / m ² .

-Other additives-
The ink jet recording medium of the present invention may contain various known additives such as acids, ultraviolet absorbers, antioxidants, fluorescent brighteners, monomers, polymerization initiators, polymerization inhibitors, and anti-bleeding agents as required. Further, an antiseptic, a viscosity stabilizer, an antifoaming agent, a surfactant, an antistatic agent, a matting agent, an anti-curling agent, a water-proofing agent and the like can be further contained.

  The ink receiving layer according to the present invention may contain an acid. By adjusting the surface pH of the ink receiving layer to 3 to 8, preferably 3.5 to 7.5 by adding an acid, yellowing resistance of the white background portion can be improved. The surface pH can be measured by the A method (coating method) among the surface PH measurements determined by the Japan Pulp and Paper Technology Association (J.TAPPI). For example, Kyoritsu Co., Ltd., which corresponds to the A method, It can be performed using a PH measurement set for paper “type MPC” manufactured by RIKEN.

  Specific examples of acids include formic acid, acetic acid, glycolic acid, oxalic acid, propionic acid, malonic acid, succinic acid, adipic acid, maleic acid, malic acid, tartaric acid, citric acid, benzoic acid, phthalic acid, isophthalic acid , Glutaric acid, gluconic acid, lactic acid, aspartic acid, glutamic acid, salicylic acid, salicylic acid metal salts (Zn, Al, Ca, Mg, etc.), methanesulfonic acid, itaconic acid, benzenesulfonic acid, toluenesulfonic acid, trifluoromethanesulfone Acid, styrenesulfonic acid, trifluoroacetic acid, barbituric acid, acrylic acid, methacrylic acid, cinnamic acid, 4-hydroxybenzoic acid, aminobenzoic acid, naphthalenedisulfonic acid, hydroxybenzenesulfonic acid, toluenesulfinic acid, benzenesulfinic acid, Sulfanilic acid, sulfamic acid, α-le Rucinic acid, β-resorcinic acid, γ-resorcinic acid, gallic acid, phloroglicin, sulfosalicylic acid, ascorbic acid, erythorbic acid, bisphenolic acid, hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, polyphosphoric acid, boric acid, boronic acid, etc. Can be mentioned. The amount of these acids added may be determined so that the surface PH of the ink receiving layer is 3-8.

  The above acid may be a metal salt (eg, sodium, potassium, calcium, cesium, zinc, copper, iron, aluminum, zirconium, lanthanum, yttrium, magnesium, strontium, cerium, etc.) or an amine salt (eg, ammonia, triethylamine). , Tributylamine, piperazine, 2-methylpiperazine, polyallylamine, etc.).

  In the present invention, it is preferable that the ink receiving layer contains a preservability improving agent such as an ultraviolet absorbent, an antioxidant, or a bleeding inhibitor. These UV absorbers, antioxidants and anti-bleeding agents that can be used in combination include alkylated phenolic compounds (including hindered phenolic compounds), alkylthiomethylphenolic compounds, hydroquinone compounds, alkylated hydroquinone compounds, tocopherol compounds, thiols Diphenyl ether compounds, compounds having two or more thioether bonds, bisphenolic compounds, O-, N- and S-benzyl compounds, hydroxybenzyl compounds, triazine compounds, phosphonate compounds, acylaminophenolic compounds, ester compounds, amide compounds, Ascorbic acid, amine antioxidant, 2- (2-hydroxyphenyl) benzotriazole compound, 2-hydroxybenzophenone compound, acrylate, water-soluble or hydrophobic metal salt, organic gold Compounds, metal complexes, hindered amine compounds (including TEMPO compounds), 2- (2-hydroxyphenyl) 1,3,5, -triazine compounds, metal deactivators, phosphite compounds, phosphonite compounds, hydroxyamine compounds, nitrones Compound, peroxide scavenger, polyamide stabilizer, polyether compound, basic auxiliary stabilizer, nucleating agent, benzofuranone compound, indolinone compound, phosphine compound, polyamine compound, thiourea compound, urea compound, hydrazide compound, amidine compound, sugar A compound, a hydroxybenzoic acid compound, a dihydroxybenzoic acid compound, a trihydroxybenzoic acid compound, and the like.

  Among these, alkylated phenolic compounds, compounds having two or more thioether bonds, bisphenolic compounds, ascorbic acid, amine-based antioxidants, water-soluble or hydrophobic metal salts, organometallic compounds, metal complexes, hindered amines It is preferable to contain at least one of a compound, a polyamine compound, a thiourea compound, a hydrazide compound, a hydroxybenzoic acid compound, a dihydroxybenzoic acid compound, and a trihydroxybenzoic acid compound.

  Specific examples of the compound include Japanese Patent Application No. 2002-13005, Japanese Patent Application Laid-Open No. 10-182621, Japanese Patent Application Laid-Open No. 2001-260519, Japanese Patent Application No. 4-34953, Japanese Patent Application No. 4-34513, Japanese Patent Application Laid-Open No. 11-170686, No. 4-34512, EP 1138509, JP-A-60-67190, JP-A-7-276808, JP-A-2001-94829, JP-A-47-10537, JP-A-58-111942, and JP-A-58-212844. 59-19945, 59-46646, 59-109055, 63-53544, JP 36-10466, 42-26187, 48-30492, 48-31255, 48-41572, 48-54965, 50-10726, U.S. Pat.No. 2,719,086, 3 No. 707,375, the 3,754,919 Patent, the 4,220,711 Patent,

Japanese Patent Publication Nos. 45-4699, 54-5324, European Published Patent Nos. 223739, 309401, 309402, 3105301, 310552, 459416, German Published Patent No. 3435443, Kaisho 54-48535, 60-107384, 60-107383, 60-125470, 60-125471, 60-125472, 60-287485, 60-287486, 60-287487, 60-287488, 61-160287, 61-18854, 61-2111079, 62-146678, 62-146680, 62-146679, 62- No. 282885, No. 62-262047, No. 63-051174, Nos. 63-89877, 63-88380 same issue, same 66-88381 JP, same 63-113536 issue,

63-163351, 63-203372, 63-224989, 63-251282, 63-267594, 63-182484, JP-A-1-239282, JP-A-2-262654, 2-71262, 3-121449, 4-291865, 4-291684, 5-611166, 5-119449, 5-188687, 5-188686, 5 No. 110490, No. 5-110437, No. 5-170361, No. 48-43295, No. 48-33212, US Pat. Nos. 4,814,262, No. 4,980,275, and the like. It is done.

  Further, various known additives such as a hardening agent, a coloring dye, a coloring pigment, a fixing agent for an ink dye, a dispersant for a pigment, a leveling agent, a viscosity stabilizer, and a pH regulator are added to the ink receiving layer. You can also.

Other additives may be used alone or in combination of two or more. Other additives may be added after being water-solubilized, dispersed, polymer-dispersed, emulsified or formed into oil droplets, or may be encapsulated in microcapsules. Moreover, as addition amount in the case of adding another additive, 0.01-10 g / m < ₂ > is preferable.

  The ink-receiving layer coating liquid in the invention may contain a surfactant. As the surfactant, any of cationic, anionic, nonionic, amphoteric, fluorine and silicone surfactants can be used. These surfactants may be used alone or in combination of two or more.

  Examples of the nonionic surfactant include polyoxyalkylene alkyl ethers and polyoxyalkylene alkyl phenyl ethers (for example, diethylene glycol monoethyl ether, diethylene glycol diethyl ether, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene nonyl). Phenyl ether, etc.), oxyethylene / oxypropylene block copolymers, sorbitan fatty acid esters (for example, sorbitan monolaurate, sorbitan monooleate, sorbitan trioleate, etc.), polyoxyethylene sorbitan fatty acid esters (for example, polyoxyethylene sorbitan mono) Laurate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan tri ), Polyoxyethylene sorbitol fatty acid esters (for example, polyoxyethylene sorbitol tetraoleate), glycerin fatty acid esters (for example, glycerol monooleate), polyoxyethylene glycerin fatty acid esters (polyoxymonostearate) Ethylene glycerol, monooleic acid polyoxyethylene glycerin, etc.), polyoxyethylene fatty acid esters (polyethylene glycol monolaurate, polyethylene glycol monooleate, etc.), polyoxyethylene alkylamine, acetylene glycols (eg, 2, 4, 7) , 9-tetramethyl-5-decyne-4,7-diol, and ethylene oxide adducts and propylene oxide adducts of the diols) Alkylene alkyl ethers are preferable. The nonionic surfactant may be contained in the ink receiving layer coating solution.

  Examples of the amphoteric surfactant include amino acid type, carboxyammonium betaine type, sulfoammonium betaine type, ammonium sulfate betaine type, imidazolium betaine type, and the like, for example, US Pat. No. 3,843,368, Those described in JP-A-59-49535, JP-A-63-236546, JP-A-5-303205, JP-A-8-262742, and JP-A-10-282619 can be suitably used. As the amphoteric surfactant, an amino acid type amphoteric surfactant is preferable, and as the amino acid type amphoteric surfactant, as described in JP-A-5-303205, for example, an amino acid (glycine, glutamic acid, Histidine acid etc.) and N-aminoacyl acids and salts thereof into which long chain acyl groups have been introduced.

  Examples of the anionic surfactant include fatty acid salts (for example, sodium stearate, potassium oleate), alkyl sulfate esters (for example, sodium lauryl sulfate, triethanolamine lauryl sulfate), and sulfonates (for example, sodium dodecylbenzenesulfonate). Alkyl sulfosuccinate (for example, sodium dioctyl sulfosuccinate), alkyl diphenyl ether disulfonate, alkyl phosphate, and the like. Examples of the cationic surfactant include alkylamine salts, quaternary ammonium salts, pyridinium salts, imidazolium salts, and the like.

  Examples of the fluorosurfactant include compounds derived via an intermediate having a perfluoroalkyl group using a method such as electrolytic fluorination, telomerization, or oligomerization. Examples thereof include perfluoroalkyl sulfonates, perfluoroalkyl carboxylates, perfluoroalkyl ethylene oxide adducts, perfluoroalkyl trialkyl ammonium salts, perfluoroalkyl group-containing oligomers, and perfluoroalkyl phosphate esters.

  The silicone surfactant is preferably a silicone oil modified with an organic group, and can have a structure in which a side chain of a siloxane structure is modified with an organic group, a structure in which both ends are modified, or a structure in which one end is modified. Examples of the organic group modification include amino modification, polyether modification, epoxy modification, carboxyl modification, carbinol modification, alkyl modification, aralkyl modification, phenol modification, and fluorine modification.

  The content of the surfactant in the ink receiving layer coating solution is preferably 0.001 to 2.0%, more preferably 0.01 to 1.0%. Further, when coating is performed using two or more liquids as the ink receiving layer coating liquid, it is preferable to add a surfactant to each coating liquid.

  The ink receiving layer according to the present invention preferably contains a high-boiling organic solvent for preventing cracking and curling. The high-boiling organic solvent is an organic compound having a boiling point of 150 ° C. or higher at normal pressure and water-soluble or A hydrophobic compound can be contained, and it may be liquid or solid at room temperature, and may be a low molecule or a polymer.

  The inkjet recording medium produced by the production method of the present invention may be composed of a single ink receiving layer containing the inorganic fine particle dispersion of the present invention, or may be composed of a plurality of layers. In the case of a plurality of layers, for example, a two-layer structure of an ink receiving layer containing silica fine particles and an ink receiving layer containing alumina hydrate may be used.

  The ink receiving layer is formed by applying the above-described ink receiving layer coating liquid on the support. More specifically, the ink receiving layer coating liquid (coating liquid A) is applied, and (1 PH 7.1 at the timing of forming a coating layer by the coating, or at the same time as (2) during the drying of the coating layer formed by the coating and before the coating layer exhibits reduced-rate drying. It can form suitably by the method (Wet-on-Wet method <WOW method>) of giving the above basic solution (solution B) to the coating layer by which it was coated, and then bridge-hardening this coating layer. Here, the crosslinking agent for crosslinking the water-soluble resin is contained in at least one of the coating solution A and the solution B. By providing the ink-receiving layer that has been crosslinked and cured as described above, it is possible to improve ink absorptivity and prevention of film cracking.

  When a mordant is added to the solution B in the case of the above-mentioned WOW method, since a lot of mordant is present near the surface of the ink receiving layer, the ink for ink jet recording, in particular, the dye is sufficiently mordanted to form a high density image. In addition, the water resistance of printed characters and images is improved. A part of the mordant may be contained in the coating liquid A, and in this case, the mordant used for the coating liquid A and the solution B may be the same or different. In addition, the porous ink receiving layer obtained as described above can absorb ink rapidly by capillary action, and can form dots with good roundness without ink bleeding.

  For example, the preparation of a coating solution for an ink receiving layer containing at least gas phase method silica, a water-soluble resin (for example, PVA) and a crosslinking agent (for example, a boron compound) is performed by using gas phase method silica and a PVA aqueous solution (for example, the above gas phase By adding a boron compound and a high speed rotating homomixer (for example, trade name “T, K homomixer” manufactured by Tokushu Kika Co., Ltd.) It can be prepared by dispersing for 20 minutes (preferably 10 to 30 minutes) under high speed rotation conditions of 2000 rpm (preferably 1000 to 5000 rpm). The obtained coating liquid is in a uniform sol state, and a porous ink-receiving layer can be formed by coating the coating liquid on a support by a coating method described later and drying it.

  The ink-receiving layer coating liquid can be made into an aqueous dispersion having an average particle diameter of 10 to 120 nm by making fine particles using a disperser. As the disperser used for obtaining the aqueous dispersion, various conventionally known dispersers can be used. From the viewpoint of efficiently dispersing the formed fine particles, the medium agitated dispersion is used. Machine, colloid mill disperser or high pressure disperser are preferred

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

  In the present invention, the coating method of the coating solution is not particularly limited, and a known coating method can be used. For example, it 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.

  The basic solution (solution B) having a pH of 7.1 or higher can be applied after application of the ink-receiving layer coating solution (coating solution A), but this application causes the coating layer to show reduced drying. Can be done before. That is, after the coating liquid A is applied, the solution B is preferably introduced while the coating layer exhibits a constant rate of drying.

  The basic solution (solution B) having a pH of 7.1 or more can contain a crosslinking agent and a mordant as necessary. The pH of the basic solution is 7.1 or higher, preferably 7.5 or higher, more preferably 8.0 or higher. If the pH is less than 7.1, the crosslinking reaction of the water-soluble polymer contained in the coating liquid A is not sufficiently performed by the crosslinking agent, and defects such as cracks occur in the ink receiving layer. The basic solution includes at least a basic substance (for example, ammonia, primary amines (ethylamine, polyallylamine, etc.), secondary amines (dimethylamine, triethylamine, etc.), tertiary amines (N-ethyl-N -Methylbutylamine, etc.), alkali metal or alkaline earth metal hydroxides) and / or salts of the basic substances.

  The mordant coating liquid (solution B) includes, for example, ammonium ion (for example, 1 to 10%) and zirconium ammonium carbonate (for example, 0.5 to 7%) that are mordants (basic compounds) in ion-exchanged water. Can be prepared by adding and stirring well. “%” In each composition means solid mass%.

  Here, “before the coating layer comes to show reduced drying” usually refers to a process for several minutes immediately after the coating of the coating liquid for the ink-receiving layer. This shows a phenomenon of “constant rate drying” in which the content of the solvent (dispersion medium) of the ink 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.

  As described above, after the ink-receiving layer coating solution is applied, the coating layer is dried until the coating layer exhibits reduced-rate drying. This drying is generally performed at 40 to 180 ° C. for 0.5 to 10 minutes (preferably 0.5 to 5 minutes). The drying time naturally varies depending on the coating amount, but usually the above range is appropriate.

  As a method of giving before the coating layer comes to show reduced-rate drying, (1) a method of further coating the solution B on the coating layer, (2) a method of spraying by a method such as spraying, (3) Examples include a method of immersing the support on which the coating layer is formed in the solution B.

  In the method (1), examples of the application method for applying the solution B include curtain flow coaters, extrusion die coaters, air doctor coaters, bread coaters, rod coaters, knife coaters, squeeze coaters, reverse roll coaters, and bar coaters. A known coating method such as the above can be used. However, it is preferable to use a method in which the coater does not directly contact an already formed coating layer, such as an extrusion die coater, a curtain flow coater, a bar coater or the like.

  After the application of the basic solution (solution B), it is generally heated at 40 to 180 ° C. for 0.5 to 30 minutes, followed by drying and curing. Especially, it is preferable to heat at 40-150 degreeC for 1 to 20 minutes.

  Further, the basic solution (solution B) can be applied simultaneously with the application of the ink receiving layer coating solution (coating solution A). In such a case, the coating solution A and the solution B are supported by the coating solution A. The ink receiving layer can be formed by simultaneously applying (multilayer coating) on the support so as to come into contact with the body, followed by drying and curing.

  The simultaneous coating (multilayer coating) can be performed by a coating method using, for example, an extrusion die coater or a curtain flow coater. After the simultaneous application, the formed application layer is dried. In this case, the drying is generally performed by heating the application layer at 15 to 150 ° C. for 0.5 to 10 minutes, preferably 40 to 100. It is carried out by heating at a temperature of 0.5 to 5 minutes.

  When the simultaneous coating (multilayer coating) is performed by, for example, an extrusion die coater, the two types of coating liquid discharged simultaneously are in the vicinity of the discharge port of the extrusion die coater, that is, before moving onto the support. In that state, it is coated on the support in multiple layers. Since the two-layer coating liquid layered before coating is likely to cause a cross-linking reaction at the interface between the two liquids when transferred to the support, the two liquids to be ejected are mixed in the vicinity of the discharge port of the extrusion die coater. As a result, thickening is likely to occur, which may hinder the application operation. Therefore, when applying simultaneously as described above, it is preferable to apply the coating solution A and the solution B together with the barrier layer solution (intermediate layer solution) between the two solutions and apply the triple layer simultaneously.

  The barrier layer solution can be selected without particular limitation. For example, an aqueous solution containing a trace amount of water-soluble resin, water, or the like can be given. The water-soluble resin is used in consideration of applicability for the purpose of a thickener and the like. For example, cellulose resin (for example, hydroxypropylmethylcellulose, methylcellulose, hydroxyethylmethylcellulose) And polymers such as polyvinylpyrrolidone and gelatin. The barrier layer liquid may contain a mordant.

  The ink receiving layer is preferably excellent in transparency. As a guide, the haze value when the ink receiving layer is formed on a transparent film is preferably 30% or less, and 15% or less. It is more preferable. The haze value can be measured with a haze meter (HGM-2DP: manufactured by Suga Test Instruments Co., Ltd.).

  A polymer fine particle dispersion may be added to the constituent layer (for example, ink receiving layer) of the ink jet recording medium of the present invention. The polymer fine particle dispersion is used for the purpose of improving film properties such as dimensional stabilization, curling prevention, adhesion prevention, film cracking prevention and the like. The polymer fine particle dispersion is described in JP-A Nos. 62-245258, 62-1316648, and 62-110066. When a polymer fine particle dispersion having a low glass transition temperature (40 ° C. or lower) is added to the ink receiving layer, cracking and curling of the layer can be prevented. Further, even when a polymer fine particle dispersion having a high glass transition temperature is added to the backcoat layer, curling can be prevented.

(Support)
As the support, any of a transparent support made of a transparent material such as plastic and an opaque support made of an opaque material such as paper can be used. In the present invention, a resin-coated support in which a thermoplastic resin layer is provided on both surfaces of a substrate such as paper is preferable. Further, a read-only optical disk such as a CD-ROM or DVD-ROM, a write-once optical disk such as a CD-R or DVD-R, or a rewritable optical disk can be used as a support, and an ink receiving layer can be provided on both sides of the label. .

  The support used in the present invention is preferably a water resistant support. It may be transparent or opaque. The thickness of the water-resistant support is preferably about 50 to 200 μm. In particular, for example, polyester resin such as polyethylene terephthalate or polyethylene naphthalate, diacetate resin, triacetate resin, acrylic resin, polycarbonate resin, polyvinyl chloride, polyimide resin, cellophane, celluloid resin film, polyolefin resin coated paper In addition, a support on which paper is coated (laminated) by using a polyolefin resin such as polyethylene or polypropylene, and further a glass plate or the like can be mentioned.

  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.

  As the resin-coated support, for example, a thermoplastic resin layer is provided on both surfaces of a highly glossy paper substrate such as art paper, coated paper, cast-coated paper, baryta paper used for silver salt photographic support, etc. And resin-coated paper used for silver salt photographic printing paper.

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

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

Hereinafter, the polyolefin resin-coated paper will be described in detail.
The base paper constituting the polyolefin resin-coated paper is not particularly limited, and commonly used paper can be used, but a smooth base paper such as that used for a photographic support is more preferable. As the pulp constituting the base paper, natural pulp, recycled pulp, synthetic pulp or the like is used alone or in combination of two or more.
This base paper is blended with additives such as sizing agent, paper strength enhancer, filler, antistatic agent, fluorescent whitening agent, and dye generally used in papermaking.

In addition, the thickness of the base paper is not particularly limited, but preferably has a good surface smoothness such as a paper that is compressed by applying a pressure during or after paper making using a calendar or the like, and has a basis weight of 30 to 250 g / m ² is preferred.

  As the resin of the resin-coated paper, a polyolefin resin or a resin curable with an electron beam can be used. Examples of polyolefin resins include low-density polyethylene, high-density polyethylene, polypropylene, polybutene, olefin homopolymers such as polypentene, or copolymers composed of two or more olefins such as ethylene-propylene copolymer, and mixtures thereof. Those having various densities and melt viscosity indices (melt index) can be used alone or in combination.

  In addition, in the resin of the resin-coated paper, white pigments such as titanium oxide, zinc oxide, talc and calcium carbonate, fatty acid amides such as stearic acid amide and arachidic acid amide, zinc stearate, calcium stearate, aluminum stearate, stearin Fatty acid metal salts such as magnesium acid, antioxidants such as Irganox 1010 and Irganox 1076, blue pigments and dyes such as cobalt blue, ultramarine blue, cecilian blue and phthalocyanine blue, magenta such as cobalt violet, fast violet and manganese purple It is preferable to add various additives such as pigments and dyes, fluorescent brighteners and ultraviolet absorbers in appropriate combinations.

  In the case of a polyolefin resin on a traveling base paper, the resin-coated paper that is preferably used in the present invention is produced by a so-called extrusion coating method in which a heat-melted resin is cast, and both surfaces thereof are coated with the resin. The In the case of a resin that is cured by an electron beam, the resin is applied by a commonly used coater such as a gravure coater or a blade coater, and then irradiated with an electron beam to cure and coat the resin. Moreover, it is preferable to subject the base paper to an activation treatment such as corona discharge treatment or flame treatment before coating the resin on the base paper. The surface (surface) on which the ink receiving layer of the support is applied has a glossy surface, a matte surface, etc., depending on the application, and the glossy surface is particularly preferentially used. It is not necessary to coat the back surface with a resin, but it is preferable to coat the resin from the viewpoint of curling prevention. The back surface is usually a matte surface, and an active treatment such as corona discharge treatment or flame treatment can be applied to the front surface or both the front and back surfaces as necessary. Moreover, there is no restriction | limiting in particular as thickness of a resin coating layer, Generally, it coats on the surface or both surfaces by thickness of 5-50 micrometers.

  Various back coat layers can be coated on the support in the present invention for antistatic properties, transport properties, anticurling properties, and the like. In the backcoat layer, an inorganic antistatic agent, an organic antistatic agent, a hydrophilic binder, latex, a curing agent, a pigment, a surfactant, and the like can be appropriately combined.

  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 the material include polyesters such as polyethylene terephthalate (PET); polysulfone, polyphenylene oxide, polyimide, polycarbonate, polyamide and the like. Of these, polyesters are preferable, and polyethylene terephthalate is particularly preferable. Although there is no restriction | limiting in particular as thickness of the said transparent support body, 50-200 micrometers is preferable at the point which is easy to handle.

  Next, the resin-coated paper will be described in detail. 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 fiber 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, and NUKP can be used. preferable. However, the ratio of LBSP and / or LDP is preferably 10% by mass or more and 70% by mass or less. The pulp is preferably a chemical pulp (sulfate pulp or sulfite pulp) with few impurities, and a pulp having a whiteness improved by bleaching is also useful.

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

The freeness of the pulp used for papermaking is preferably 200 to 500 ml as defined by CSF, and the fiber length after beating is a 24 mesh residual mass% and a 42 mesh residual as defined in JIS P-8207. 30 to 70% of the sum with the mass% of is preferable. In addition, it is preferable that the mass% of 4 mesh remainder is 20 mass% or less. The basis weight of the base paper is preferably 30 to 250 g, and particularly preferably 50 to 200 g. The thickness of the base paper is preferably 40 to 250 μm. The base paper can be given a high smoothness by calendering at the paper making stage or after paper making. The density of the base paper is generally 0.7 to 1.2 g / m ² (JIS P-8118). Furthermore, the base paper stiffness is preferably 20 to 200 g under the conditions specified in JIS P-8143.

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

  The surfaces on both sides of the base paper can generally be coated with polyethylene. The polyethylene is mainly low-density polyethylene (LDPE) and / or high-density polyethylene (HDPE), but other LLDPE, polypropylene and the like can also be used in part.

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

  Polyethylene-coated paper can be used as glossy paper, or when it is coated by melt-extruding polyethylene onto the surface of the base paper, a matte or silky surface that can be obtained with ordinary photographic printing paper by performing a so-called molding process. 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.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples. In the examples, “parts” and “%” are based on mass.

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

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

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

  Furthermore, after the corona discharge treatment is applied to the felt surface (surface) side where the resin layer is not provided, anatase-type titanium dioxide 10%, a trace amount of ultramarine blue, and a fluorescent whitening agent 0.01% (vs. polyethylene) A low-density polyethylene containing MFR (melt flow rate) 3.8 is extruded to a thickness of 40 μm using a melt extruder to form a high gloss thermoplastic layer on the surface side of the base paper. (Hereinafter, this high-gloss surface is referred to as a “front side”), which was used as a support.

(Preparation of inorganic fine particle dispersion 1)
1 part of dimethyldiallylammonium chloride (Charol DC902P, 50% aqueous solution, Daiichi Kogyo Seiyaku Co., Ltd.) is added as a water-soluble organic cation compound to 553 parts of ion-exchanged water stirred at 2000 rpm by a homomixer, followed by inorganic fine particles. Gas phase method silica (average primary particle diameter 7 nm, specific surface area 300 m ² / g by BET method) was added 100 parts, and then zirconyl acetate (Zircosol ZA-30 50% aqueous solution as a water-soluble polyvalent metal compound) ) 0.54 part was added and dissolved, and processed with a homomixer at 4000 rpm for 120 min to prepare a preliminary dispersion (preliminary dispersion step). After this preliminary dispersion is stored at 5 ° C. for 3 days, it is dispersed in a liquid-liquid collision type disperser (manufactured by Optimizer Sugino Machine) at 170 MPa in one pass, and an inorganic fine dispersion having a silica concentration of about 16%. 1 was prepared (this dispersion step). The volume average particle diameter of the inorganic fine particles in the inorganic fine dispersion liquid 1 was 0.12 μm. The volume average particle diameter of the inorganic fine particles was measured by HORIBA LA920.

(Preparation of coating liquid 1 for ink receiving layer)
The following components (2) to (7) are added to the inorganic fine dispersion liquid obtained as described above, and dispersed again for 20 minutes at a homomixer rotation speed of 2000 rpm. 1 was obtained.

<Composition of Ink Receptive Layer Coating Liquid 1>
(1) Inorganic fine dispersion 1 58.9 parts (2) Boric acid 3.9 parts (3) Ion exchange water 1.3 parts (4) PVA solution (made by Kuraray) 31.2 parts (5) Superflex 650 (Daiichi Kogyo Seiyaku Co., Ltd.) 2.2 parts (6) Ethanol 1.2 parts (7) Polyaluminum chloride 1.3 parts

(Preparation of mordant coating solution)
The following components were mixed using a propeller stirrer to prepare a mordant coating solution.
(1) Boric acid 0.7 parts (2) Ammonium carbonate 5.0 parts (3) Ammonium zirconium carbonate 1.27 parts (4) Ion exchange water 87.08 parts (5) Emulgen 109P (10% aqueous solution) 0 copies

The front surface of the support obtained as described above was subjected to corona discharge treatment, and the ink receiving layer coating solution 1 was applied to the front surface at a coating amount of 175 ml / m ² using an extrusion die coater. It was applied (application process), and dried with a hot air dryer at 60 ° C. (wind speed 3 to 8 m / sec) until the solid content concentration of the application layer reached 20%. The coating layer showed constant rate drying during this period. Before showing the reduction drying, it was immersed in the mordant coating solution for 3 seconds to deposit 15 g / m ² on the coating layer, and further dried at 60 ° C. for 10 minutes (curing step). Thus, an inkjet recording paper 1 provided with an ink receiving layer having a dry film thickness of 40 μm was obtained.

[Example 2]
An inorganic fine particle dispersion 2 was prepared in the same manner as in Example 1 except that the preliminary dispersion was stored at 10 ° C. for 2 days. The volume average particle diameter of the inorganic fine particles in the inorganic fine particle dispersion 2 was 0.12 μm. Further, an ink jet recording paper 2 was obtained using the inorganic fine particle dispersion 2 in the same manner as in Example 1.

[Example 3]
An inorganic fine particle dispersion 3 was prepared in the same manner as in Example 1 except that the preliminary dispersion was stored at 10 ° C. for 7 days. The volume average particle diameter of the inorganic fine particles in the inorganic fine particle dispersion 3 was 0.12 μm. Further, an inkjet recording paper 3 was obtained using the inorganic fine particle dispersion 3 in the same manner as in Example 1.

[Example 4]
An inorganic fine particle dispersion 4 was prepared in the same manner as in Example 1 except that the preliminary dispersion was stored at 15 ° C. for 3 days. The volume average particle diameter of the inorganic fine particles in the inorganic fine particle dispersion 4 was 0.12 μm. Also, an inkjet recording paper 4 was obtained in the same manner as in Example 1 using the inorganic fine particle dispersion 4.

[Comparative Example 1]
When the preliminary dispersion was stored at 0 ° C. for 1 day, the preliminary dispersion was frozen and an ink jet recording paper could not be obtained.

[Comparative Example 2]
An inorganic fine particle dispersion 5 was prepared in the same manner as in Example 1 except that the preliminary dispersion was stored at 20 ° C. for 3 days. The volume average particle diameter of the inorganic fine particles in the inorganic fine particle dispersion 5 was 0.12 μm. Further, an inkjet recording paper 5 was obtained in the same manner as in Example 1 using the inorganic fine particle dispersion 5.

[Comparative Example 3]
An inorganic fine particle dispersion 6 was prepared in the same manner as in Example 1 except that the preliminary dispersion was stored at 10 ° C. for 1 day. The volume average particle diameter of the inorganic fine particles in the inorganic fine particle dispersion 6 was 0.12 μm. Further, an inkjet recording paper 6 was obtained in the same manner as in Example 1 using the inorganic fine particle dispersion 6.

  Using the inkjet recording paper obtained as described above, the printing density (black density), the degree of unevenness at the end of the coating liquid, and the overall characteristics (overall evaluation) were evaluated based on the following criteria. The obtained results are shown in Table 1.

<Measurement of print density>
Using the inkjet printer PMG800C (manufactured by Seiko Epson Corporation), black solid images were printed on the inkjet recording sheets of Examples and Comparative Examples obtained above, and the resulting black portion density was measured using a reflection densitometer (Xrite 938, Xrite) and evaluated according to the following criteria.
○: 2.3 or more Δ: 2.2 or more, less than 2, 3 ×: less than 2.2

<Degree of unevenness>
The thicknesses of the convex portions at the normal portion and the end portion of the recording paper were measured with a Mitutoyo Digimatic Indicator: ID-H5030, and evaluated by the rate of increase in the thickness of the convex portion with respect to the normal portion.
○: The rate of increase in thickness with respect to the thickness of the normal part is less than 150% Δ: The rate of increase in thickness with respect to the thickness of the normal part is 150% or more and less than 170% ×: The rate of increase in thickness with respect to the thickness of the normal part is 170% or more

<Comprehensive evaluation>
The inkjet recording paper was comprehensively evaluated according to the following criteria.
○: Printing density ○
△: Either one of the print density irregularities △ Neither x contains x: Print density One of the irregularities x

  From Table 1, it can be seen that the degree of unevenness deteriorates when the number of holding days is small. It can also be seen that the print density decreases when the holding temperature is high.

Claims (11)

A pre-dispersing step of pre-dispersing a mixed solution containing a water-soluble organic cation compound, a water-soluble polyvalent metal compound and inorganic fine particles to obtain a pre-dispersion, and a book for obtaining an inorganic fine particle dispersion by main dispersion of the pre-dispersion A dispersion step, and a method for producing an inorganic fine particle dispersion comprising:
A method for producing an inorganic fine particle dispersion in which the preliminary dispersion is held for at least 2 days at a temperature of 15 ° C. or lower and not frozen for at least 2 days.   The method for producing an inorganic fine particle dispersion according to claim 1, wherein the average primary particle diameter of the inorganic fine particles is 30 nm or less, and the volume average particle diameter of the inorganic fine particles in the inorganic fine particle dispersion is 200 nm or less.   The method for producing an inorganic fine particle dispersion according to claim 1, wherein the inorganic fine particles are vapor phase silica. The method for producing an inorganic fine particle dispersion according to any one of claims 1 to 3, wherein the specific surface area of the inorganic fine particles by BET method is 200 m ² / g or more.   The method for producing an inorganic fine particle dispersion according to any one of claims 1 to 4, wherein the water-soluble polyvalent metal compound is a trivalent or higher valent metal compound.   The method for producing an inorganic fine particle dispersion according to claim 5, wherein the trivalent or higher-valent metal compound is an aluminum compound and / or a zirconium compound.   The method for producing an inorganic fine particle dispersion according to claim 6, wherein the aluminum compound is basic polyaluminum hydroxide.   The method for producing an inorganic fine particle dispersion according to claim 6, wherein the zirconium compound is zirconium acetate or ammonium zirconium carbonate.   The method for producing an inorganic fine particle dispersion according to any one of claims 1 to 8, wherein the water-soluble organic cation compound is a compound having a primary to tertiary amino group, a quaternary ammonium base, or a phosphonium base.   An inorganic fine particle dispersion produced by the method for producing an inorganic fine particle dispersion according to any one of claims 1 to 9.   A method for producing an ink jet recording medium, comprising a coating step of coating an ink receiving layer coating liquid containing the inorganic fine particle dispersion according to claim 10 on a support.