JP2009178913A - Inkjet recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording method in which a bronze after image recording can be suppressed. <P>SOLUTION: The inkjet recording method is characterized in that, to an inkjet recording medium in which the surface of a support is provided with an ink receiving layer and an outermost surface layer furthest from the support on the side with the ink receiving layer, and the outermost surface layer contains alkali soluble organic fine grains, recording is performed using water soluble ink with the pH of ≥9 containing a color material. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ink jet recording method using a pigment ink.

  With the rapid development of the information technology industry in recent years, various information processing systems have been developed, and recording methods and recording apparatuses suitable for each information processing system have been put into practical use. Among these, the ink jet recording method is widely used because it can record on various recording materials, the hardware (device) is relatively inexpensive and compact, and has excellent quietness. ing. In the recording using the ink jet recording method, it has become possible to obtain a so-called photographic-like high quality recorded matter.

  In general, recording materials for ink-jet recording are (1) fast-drying (high ink absorption speed), (2) proper and uniform dot diameter (no bleeding), and (3) granular (4) High roundness of dots, (5) High color density, (6) High saturation (no dullness), (7) Water resistance of image area (8) High whiteness, (9) High storage stability (no yellowing coloring or bleeding of images after long-term storage), (10) It is required to have properties such as being hard to deform and having good dimensional stability (low curl) and (11) good hard running performance.

In general, an ink jet recording method using a pigment ink is considered to be superior in storage stability compared to an ink jet recording method using a dye ink. However, it is known that the ink jet recording method using pigment ink may cause other problems such as the phenomenon that bronze, which is different from the original color of pigment, occurs on the surface, the glossiness is lowered, and the abrasion resistance is deteriorated. ing. As a method for solving such a problem, an ink jet recording method in which heating and pressurizing is performed after image formation is known (for example, see Patent Document 1).
Further, as a method for solving the deterioration of scratch resistance without requiring heat and pressure treatment, a method of incorporating a polymer resin contained in a pigment ink into an ink receiving layer is known (for example, see Patent Document 2). ).

Further, the ink jet recording material has a pigment fixing layer containing a composite layer containing a porous layer, inorganic fine particles and a first thermoplastic resin, and a second thermoplastic resin for improving glossiness. A method using an ink jet recording medium for pigment ink is disclosed (for example, see Patent Document 3).
JP 2004-181803 A JP 2003-72230 A JP 2002-178629 A

However, in the method described in Patent Document 1, the inkjet recording system and the printing process are complicated, and there are problems in terms of cost and the like. In addition, the method described in Patent Document 2 is insufficient in terms of improving the suppression of bronze. Further, the method described in Patent Document 3 is insufficient in fine printing.
An object of the present invention is to provide an ink jet recording method capable of suppressing bronzing after image recording.

<1> An ink jet recording medium having an ink receiving layer and an outermost surface layer farthest from the support having the ink receiving layer on the support, and containing alkali-soluble organic fine particles in the outermost surface layer. An ink jet recording method comprising recording using an aqueous ink containing a material and having a pH of 9 or more.
<2> The inkjet recording method according to <1>, wherein the alkali-soluble organic fine particles are vinyl acetate copolymer fine particles.
<3> The inkjet recording method according to <1> or <2>, wherein the coloring material of the water-based ink is a pigment.

  According to the present invention, it is possible to provide an ink jet recording method capable of suppressing bronzing after image recording.

The inkjet recording method of the present invention comprises, on a support, at least one ink receiving layer and an outermost surface layer farthest from the support having the ink receiving layer, and the alkali-soluble organic fine particles are added to the outermost surface. The ink jet recording medium contained in the surface layer is recorded using a water-based ink having a pH of 9 or more containing a coloring material.
In the present invention, the occurrence of bronzing after recording is suppressed by combining an ink jet recording medium containing alkali-soluble organic fine particles in the outermost surface layer and an aqueous ink having a specific pH as the ink. In addition, bronzing can be effectively suppressed without post-processing such as heating after image recording.
Hereinafter, the ink jet recording medium and ink in the present invention will be described in detail.

  The ink jet recording medium in the present invention has an ink receiving layer and an outermost surface layer farthest from the support on the side having the ink receiving layer on a support (hereinafter also referred to as a base material, particularly a base paper), and an alkali It is configured to contain soluble organic fine particles in the outermost surface layer. As a result, bronzing is suppressed and an excellent high quality image can be formed.

  The ink jet recording medium of the present invention has an ink receiving layer and an outermost surface layer on the side having the ink receiving layer on a support, and has other layers as necessary.

[Outermost surface layer]
The outermost surface layer contains alkali-soluble organic fine particles in order to suppress and improve the occurrence of bronzing after ink jet recording, and may further contain other components as necessary.

(Alkali-soluble organic fine particles)
Alkali-soluble is defined as the property that the dried organic fine particles are dissolved in a 0.1 molar aqueous sodium hydroxide solution.
Specifically, when organic fine particles applied and dried at about 5 g / m ^{2 on} PET are immersed in water and a 0.1 molar aqueous sodium hydroxide solution at room temperature and then dried, the weight is as follows. It is defined as soluble.
(Mass after immersion in water and drying (g / m ² ))> (Mass after immersion in 0.1N sodium hydroxide aqueous solution and drying (g / m ² ))

  Specifically, the alkali-soluble organic fine particles (hereinafter, also simply referred to as “specific organic fine particles”) in the present invention are vinyl acetate-acrylic emulsion, acrylic-urethane emulsion, vinyl acetate-ethylene emulsion, styrene-acrylic. Emulsion, acrylic emulsion, vinyl acetate emulsion, chlorinated polyolefin emulsion, multi-component copolymer emulsion such as ethylene-vinyl acetate-acryl, SBR latex, NBR latex, MBR latex, carboxylated SBR latex, carboxylated NBR latex , Carboxylated MBR latex, water-soluble urethane-based resin, water-soluble polyester resin, and the like can be appropriately selected in consideration of alkali solubility.

Among these, vinyl acetate-acrylic emulsions, vinyl acetate-ethylene emulsions, vinyl acetate emulsions, multi-component copolymer emulsions such as ethylene-vinyl acetate-acrylic, etc., or vinyl acetate copolymer fine particles are preferable.
In the present invention, the specific organic fine particles may be used alone or in combination of two or more specific organic fine particles.
The two or more types of specific organic fine particles may have different monomer compositions, particle sizes, and / or polymerization degrees.

  The particle diameter of the specific organic fine particles is not particularly limited, but usually those having a range of 0.01 μm to 20 μm can be used, preferably 0.02 μm to 10 μm, more preferably 0.02 μm to 5 μm. .

The content of the specific organic fine particles contained in the outermost surface layer is preferably 0.1 to 10 g / m ² and more preferably 0.2 to 5 g / m ² from the viewpoint of suppressing bronzing. .

(Other ingredients)
In the present invention, in addition to surfactants and hardeners, coloring dyes, coloring pigments, ink dye fixing agents, UV absorbers, antioxidants, pigment dispersants, antifoaming agents, leveling agents, preservatives, fluorescent Various known additives such as a brightener, a viscosity stabilizer, and a pH adjuster can also be added.

[Ink receiving layer]
The ink receiving layer can be composed of a water-soluble resin and fine particles, and preferably, a water-soluble resin, fine particles, a crosslinking agent capable of crosslinking the water-soluble resin, and a mordant and other components as necessary (such as a surfactant). ) And can be configured.

  The ink receiving layer is formed into a porous structure by containing fine particles, thereby improving the ink absorption performance. In particular, when the solid content of the fine particle ink receiving layer is 50% by mass or more, and more preferably more than 60% by mass, it is possible to obtain a more favorable porous structure, thereby further improving the ink absorbability. be able to. Here, the solid content of the fine particle ink receiving layer is a content calculated based on components other than water in the composition constituting the ink receiving layer.

  The porous ink-receiving layer is a layer having a porosity of 50 to 75%, preferably 60 to 70%. If the porosity is 50% or less, ink absorbability may be insufficient, and if it is 75% or more, a problem of powder falling due to insufficient binder may occur. Further, in view of the quality of the ink jet recording medium, the thickness of the ink receiving layer is preferably 20 to 40 μm.

-Fine particles-
As the fine particles, either organic fine particles or inorganic fine particles can be used. Preferred examples of the organic fine particles include polymer fine particles obtained by, for example, emulsion polymerization, microemulsion polymerization, soap-free polymerization, seed polymerization, dispersion polymerization, suspension polymerization, and the like. Specifically, polyethylene, polypropylene, Examples include polystyrene, polyacrylate, polyamide, silicon resin, phenol resin, natural polymer powder, latex or emulsion polymer fine particles, and the like.

  Examples of the inorganic fine particles include silica fine particles, colloidal silica, titanium dioxide, barium sulfate, calcium silicate, zeolite, kaolinite, halloysite, mica, talc, calcium carbonate, magnesium carbonate, calcium sulfate, pseudoboehmite, zinc oxide, Examples thereof include zinc hydroxide, alumina, aluminum silicate, calcium silicate, magnesium silicate, zirconium oxide, zirconium hydroxide, cerium oxide, lanthanum oxide, and yttrium oxide.

  Among these, inorganic fine particles are preferable from the viewpoint of ink absorbability and image stability, and silica fine particles, colloidal silica, alumina fine particles, or pseudoboehmite are preferable from the viewpoint of forming a better porous structure. The fine particles may be used as primary particles or in a state where secondary particles are formed. The average primary particle size of these fine particles is preferably 2 μm or less, and more preferably 200 nm or less.

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

Vapor phase silica is different from hydrous silica in terms of the density of silanol groups on the surface, the presence or absence of vacancies, etc., and exhibits different properties, but is suitable for forming a three-dimensional structure with a high porosity. The reason for this is not clear, but in the case of hydrous silica, the density of silanol groups on the surface of the fine particles is high at 5 to 8 / nm ² , and the silica fine particles tend to aggregate closely (aggregate). In the case of the method silica, the density of silanol groups on the surface of the fine particles is 2 to 3 / nm ² , so that it is sparse soft aggregation (flocculate), and as a result, it is assumed that the structure has a high porosity. Is done.

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

  The average primary particle size of the vapor phase silica is preferably 30 nm or less, more preferably 20 nm or less, particularly preferably 10 nm or less, and most preferably 3 to 10 nm. Vapor phase silica is easy to adhere to each other by hydrogen bonds with silanol groups, so that when the average primary particle size is 30 nm or less, a structure with a large porosity can be suitably formed, and ink absorption characteristics are effective. Can be improved.

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

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

  About the pore structure of pseudo boehmite, the average pore radius is preferably 1 to 25 nm, and more preferably 2 to 10 nm. The pore volume is preferably 0.3 to 2.0 ml / g, more preferably 0.5 to 1.5 ml / g. Here, the pore radius and the pore volume are measured by a nitrogen adsorption / desorption method, and can be measured using, for example, a gas adsorption / desorption analyzer (for example, trade name “Omni Soap 369” manufactured by Coulter).

  Among the alumina fine particles, vapor-phase method alumina fine particles are preferable because of their large specific surface area. The average primary particle diameter of the vapor phase alumina fine particles is preferably 50 nm or less, and more preferably 20 nm or less. Furthermore, colloidal silica having an average primary particle size of 50 nm or less is also preferable.

  The above-mentioned fine particles are, for example, JP-A-10-81064, JP-A-10-119423, JP-A-10-157277, JP-A-10-217601, JP-A-11-348409, JP-A-2001-138621, JP-A-2000-43401. 2000-212235, 2000-309157, 2001-96897, 2001-138627, JP-A-11-91242, 8-2087, 8-2090, 8-2091, The embodiments disclosed in JP-A-8-2093, JP-A-8-174992, JP-A-11-192777, JP-A-2001-301314 and the like can also be preferably used.

-Water-soluble resin-
The ink-receiving layer preferably contains a water-soluble resin. Examples of the water-soluble resin include a polyvinyl alcohol resin [polyvinyl alcohol (PVA), acetoacetyl, which is a resin having a hydroxy group as a hydrophilic structural unit. Modified polyvinyl alcohol, cation modified polyvinyl alcohol, anion modified polyvinyl alcohol, silanol modified polyvinyl alcohol, polyvinyl acetal, etc.], cellulose resin [methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC), Hydroxypropylcellulose (HPC), hydroxyethylmethylcellulose, hydroxypropylmethylcellulose, etc.], chitins, chitosans, starch, ether Resin [polyethylene oxide (PEO), polypropylene oxide (PPO), polyethylene glycol (PEG), polyvinyl ether (PVE), etc.], resin having carbamoyl group [polyacrylamide (PAAM), polyvinyl pyrrolidone (PVP), poly Acrylic hydrazide, etc.]. Among these, polyvinyl alcohol resins, cellulose resins, resins having an ether bond, resins having a carbamoyl group, resins having a carboxyl group, and gelatins are preferable.
Moreover, the polyacrylic acid salt which has a carboxyl group as a dissociable group, maleic acid resin, alginate, gelatins, etc. can be mentioned.

  Among these, polyvinyl alcohol resin is particularly preferable. Examples of the polyvinyl alcohol include Japanese Patent Publication No. 4-52786, Japanese Patent Publication No. 5-67432, Japanese Patent Publication No. 7-29479, Japanese Patent No. 2537827, Japanese Patent Publication No. 7-57553, Japanese Patent No. 2502998, and Japanese Patent No. 3053231. JP-A-63-176173, JP-A-2604367, JP-A-7-276787, JP-A-9-207425, JP-A-11-58941, JP-A-2000-135858, JP-A-2001-205924, JP 2001-287444, JP 62-278080, JP 9-39373, JP 2750433, JP 2000-18801, JP 2001-213045, JP 2001-328345, JP 8 -324105, JP-A-11-348417, etc. It is below.

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

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

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

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

<Content ratio of fine particles and water-soluble resin>
The mass ratio [PB ratio; = x / y] of the mass (x) of the fine particles and the mass (y) of the water-soluble resin greatly affects the film structure and film strength of the ink receiving layer. That is, as the mass ratio (PB ratio) increases, the porosity, pore volume, and surface area (per unit mass) increase, but the density and strength tend to decrease.
As the PB ratio (x / y) in the ink receiving layer, the decrease in film strength and cracking during drying caused by the PB ratio being too large are prevented, and the PB ratio is too small, From the viewpoint of preventing the ink absorbability from being lowered due to the void being easily blocked by the resin and decreasing the porosity, 1.5 to 10 is preferable.

  In addition, since stress may be applied to the ink jet recording medium when passing through the transport system of the ink jet printer, the ink receiving layer needs to have sufficient film strength, and when it is cut into a sheet shape In addition, the ink receiving layer needs to have sufficient film strength from the viewpoint of preventing the ink receiving layer from cracking or peeling. In consideration of these, the PB ratio is more preferably 5 or less, and more preferably 2 or more from the viewpoint of ensuring high-speed ink absorbability in an inkjet printer.

For example, a coating solution in which gas phase method silica fine particles 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 and dried. In this case, a three-dimensional network structure in which the secondary particles of silica fine particles are network chains is formed, the average pore diameter is 25 nm or less, the porosity is 50 to 80%, the pore specific volume is 0.5 ml / g or more, 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 is a porous layer in which a coating layer containing fine particles and a water-soluble resin further contains a crosslinking agent capable of crosslinking the water-soluble resin, and is cured by a crosslinking reaction between the crosslinking agent and the water-soluble resin. Some embodiments are preferred.

Boron compounds are preferred for crosslinking the water-soluble resin, particularly polyvinyl alcohol resin. 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), pentaborate (for example, KB ₅ O ₈ · 4H ₂ O, Ca ₂ B ₆ O ₁₁ · 7H ₂ O, CsB ₅ O ₅ ), etc. Of these, borax, boric acid, and borate are preferable, and boric acid is particularly preferable in that a crosslinking reaction can be promptly caused.

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

Isocyanate compounds such as 1,6-hexamethylene diisocyanate; Aziridine compounds described in US Pat. Nos. 3,017,280 and 2,983611; Carboximide compounds described in US Pat. No. 3,100,704; Glycerol triglycidyl Epoxy compounds such as ether; Ethyleneimino compounds such as 1,6-hexamethylene-N, N′-bisethyleneurea; Halogenated carboxaldehyde compounds such as mucochloric acid and mucophenoxycyclolic acid; 2,3-dihydroxy Dioxane-based compounds such as dioxane; titanium-containing aluminum sulfate, chromium alum, potassium alum, metal-containing compounds such as zirconyl acetate, chromium acetate, polyamine compounds such as tetraethylenepentamine, hydrazide compounds such as adipic acid dihydrazide, A low molecule or polymer containing two or more oxazoline groups.
The crosslinking agents may be used alone or in combination of two or more.

  In the crosslinking and curing, a coating liquid (hereinafter also referred to as “ink receiving layer coating liquid” or “first liquid”) and / or a base described below, which contains fine particles, a water-soluble resin, and the like to form an ink receiving layer. And (1) at the same time when the first liquid is applied to form a coating layer, or (2) during the drying of the coating layer formed by applying the first liquid. In any case before the coating layer exhibits reduced-rate drying, a basic solution having a pH of 7.1 or higher (hereinafter also referred to as “second liquid”) is applied to the coating layer. Is preferred.

The application of the cross-linking agent is preferably performed as follows when a boron compound is taken as an example. That is, when the ink receiving layer is a layer obtained by crosslinking and curing a coating layer coated with a coating solution (first solution) containing a water-soluble resin containing fine particles and polyvinyl alcohol, crosslinking curing is performed by (1) At the same time that one liquid is applied to form a coating layer, (2) any one of the coating layers formed by applying the first liquid and being dried and before the coating layer exhibits reduced-rate drying Sometimes, it is carried out by applying a basic solution (second liquid) having a pH of 7.1 or higher to the coating layer. The boron compound as the crosslinking agent may be contained in either the first liquid or the second liquid, and may be contained in both the first liquid and the second liquid.
1-50 mass% is preferable with respect to water-soluble resin, and, as for the usage-amount of a crosslinking agent, 5-40 mass% is more preferable.

-Mordant-
In the present invention, a mordant is preferably contained in the ink receiving layer in order to further improve the water resistance and aging resistance of the formed image. As the mordant, any of an organic mordant such as a cationic polymer (cationic mordant) and an inorganic mordant such as a water-soluble metal compound can be used. Of these, organic mordants are preferable, and cationic mordants are particularly preferable.

  The presence of the mordant in at least the upper layer of the ink receiving layer allows interaction with the liquid ink having an anionic dye as a coloring material, thereby stabilizing the coloring material and preventing water resistance and aging resistance. Further improvements can be made.

  In this case, it may be contained in either the ink receiving layer coating liquid (first liquid) or the basic solution (second liquid) when forming the ink receiving layer, but inorganic fine particles (especially gas phase method silica). It is preferable to contain and use in the 2nd liquid used as a liquid different from the liquid containing. That is, when the mordant is added directly to the ink receiving layer coating solution, aggregation may occur in the presence of an anion charge-containing silica vapor, but the mordant containing solution and the ink receiving layer coating solution are respectively If the method of independently preparing and coating each is employed, it is not necessary to consider the aggregation of inorganic fine particles, and the range of mordant selection is expanded.

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 is also used. be able to.
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 (hereinafter referred to as “mordant monomer”), the mordant monomer, Those obtained as copolymers or condensation polymers with other monomers (hereinafter referred to as “non-mordant polymer”) are preferred. 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.
Other examples of the copolymerizable monomer include N-vinylimidazole and N-vinyl-2-methylimidazole.

In addition, allylamine, diallylamine, derivatives thereof, salts and the like can also be used. Examples of such compounds include allylamine, allylamine hydrochloride, allylamine acetate, allylamine sulfate, diallylamine, diallylamine hydrochloride, diallylamine acetate, diallylamine sulfate, diallylmethylamine and salts thereof (for example, Hydrochloride, acetate, sulfate, etc.), diallylethylamine and salts thereof (for example, hydrochloride, acetate, sulfate, etc.), diallyldimethylammonium salt (chloride, acetic acid as counter anions of the salt) Ion sulfate, etc.). In addition, since these allylamines and diallylamine derivatives are inferior in polymerizability in the amine form, it is a general production method to polymerize in the form of a salt and desalting as required.
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.
Examples of the non-mordant monomer include (meth) acrylic acid alkyl ester; (meth) acrylic acid cycloalkyl ester such as cyclohexyl (meth) acrylate; (meth) acrylic acid aryl ester such as phenyl (meth) acrylate; Aralkyl esters such as (meth) benzyl acrylate; Aromatic vinyls such as styrene, vinyl toluene and α-methylstyrene; Vinyl esters such as vinyl acetate, vinyl propionate and vinyl versatic acid; Allyl esters such as allyl acetate Halogen-containing monomers such as vinylidene chloride and vinyl chloride; vinyl cyanide such as (meth) acrylonitrile; olefins such as ethylene and propylene; and the like.

  The (meth) acrylic acid alkyl ester is preferably a (meth) acrylic acid alkyl ester having 1 to 18 carbon atoms in the alkyl moiety, 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 a cationic mordant, polydiallyldimethylammonium chloride, polymethacryloyloxyethyl-β-hydroxyethyldimethylammonium chloride, polyethyleneimine, polyallylamine and derivatives thereof, polyamide-polyamine resin, cationized starch, dicyandiamide formalin condensate, dimethyl Addition of 2-hydroxypropylammonium salt polymer, polyamidine, polyvinylamine, dicyandiamide-formalin polycondensate, dicyanamide-cachinic resin, dicyanamide-diethylenetriamine-polycondensate, polyamine-type katine resin, epichlorohydrin-dimethylamine Polymer, dimethyldialin ammonium chloride-SO ₂ copolymer, diallylamine salt-SO ₂ copolymer, A (meth) acrylate-containing polymer having a quaternary ammonium base-substituted alkyl group in the ester portion, a styryl polymer having a quaternary ammonium base-substituted alkyl group, and the like can also be mentioned as preferable examples.

  Specific examples of the cationic mordant include JP-A Nos. 48-28325, 54-74430, 54-124726, 55-22766, 55-142339, 60-23850, and the like. 60-23851, 60-23852, 60-23853, 60-57836, 60-60643, 60-118834, 60-122940, 60-122941, 60- Nos. 122942, 60-235134, JP-A-1-161236, U.S. Pat.Nos. 2,484,430, 2,548,564, 3,148,061, 3,309,690, 4,115,124, 4,124,386, 4,193,800, 4,227,8353 Nos. 4282305 and 4450224, JP No. 161236, No. 10-81064, No. 10-119423, No. 10-157277, No. 10-217601, No. 11-348409, JP-A No. 2001-138621, No. 2000-43401, No. 2000- 211235, 2000-309157, 2001-96897, 2001-138627, JP-A-11-91242, 8-2087, 8-2090, 8-2091, 8-2093 No. 8-1744992, No. 11-192777, JP-A No. 2001-301314, JP-B No. 5-35162, No. 5-35163, No. 5-35164, No. 5-88846, JP-A No. 7-8846 No. 118333, Japanese Patent Laid-Open No. 2000-344990, etc., Japanese Patent Nos. 2648847, 266167 Include those such as described in the specification of the issue, and the like. Among these, polyallylamine and derivatives thereof are preferable, and diallyldialkyl cationic polymers are preferable in terms of structure.

  As the polyallylamine or a derivative thereof, various known allylamine polymers and derivatives thereof can be used. Examples of such derivatives include salts of polyallylamine and acids (acids include inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid and nitric acid, methanesulfonic acid, toluenesulfonic acid, acetic acid, propionic acid, cinnamic acid, (meth) An organic acid such as acrylic acid, or a combination thereof, or a salt of only a part of allylamine), a derivative of polyallylamine by a polymer reaction, a copolymer of polyallylamine and another copolymerizable monomer Specific examples of the monomer include (meth) acrylic acid esters, styrenes, (meth) acrylamides, acrylonitrile, vinyl esters and the like.

  Specific examples of polyallylamine and derivatives thereof include JP-B-62-31722, JP-B-2-14364, JP-B-63-43402, JP-A-63-43403, JP-A-63-45721, and JP-A-63-29881. Japanese Patent Publication No. 1-26362, No. 2-56365, No. 2-57084, No. 4-41686, No. 6-2780, No. 6-45649, No. 6-15592, No. 4-68622, Patents No. 3199227, No. 3008369, JP-A-10-330427, JP-A-11-21321, JP-A-2000-281728, JP-A-2001-106636, JP-A-62-256801, JP-A-7-173286, 7-213897, 9-235318, 9-302026, 11-21321, WO99 / 21901 , No. WO99 / 19372, JP-A-5-140213, compounds described in JP Kohyo No. 11-506488, and the like.

Among the above-mentioned cationic mordants, diallyl dialkyl cationic polymers are preferable, and diallyl dimethyl cationic polymers are particularly preferable. The cationic mordant is preferably a cationic polymer having a weight average molecular weight of 60000 or less, particularly 40000 or less, from the viewpoint of dispersibility, particularly prevention of thickening.
The cationic mordant is also useful as the fine particle dispersant described above.

  Further, when added to the ink receiving layer coating solution, the sulfate ion concentration in the coating solution is preferably 1.5% by mass or less from the viewpoint of preventing thickening of the solution. This sulfate ion is contained in the polymerization initiator at the time of production of the cationic polymer, and since it remains in the polymer, the cationic mordant is formed using a polymerization initiator that does not emit sulfate ion. Is desirable.

  Examples of the inorganic mordant include polyvalent water-soluble metal salts and hydrophobic metal salt compounds. Specifically, 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, europium, gadolinium, dysprosium, erbium, ytterbium, hafnium, tungsten, bismuth metal salts or complexes.

  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, and second chloride. Copper, ammonium chloride (II) chloride dihydrate, copper sulfate, cobalt chloride, cobalt thiocyanate, cobalt sulfate, nickel sulfate hexahydrate, nickel chloride hexahydrate, nickel acetate tetrahydrate, nickel ammonium sulfate Hexahydrate, nickel amidosulfate tetrahydrate, aluminum sulfate, aluminum alum, basic polyaluminum hydroxide, aluminum sulfite, aluminum thiosulfate, polyaluminum chloride, aluminum nitrate nonahydrate, aluminum chloride hexahydrate , Ferrous bromide, ferrous chloride, ferric chloride, sulfur Ferrous sulfate, ferric sulfate, zinc phenolsulfonate, zinc bromide, zinc chloride, zinc nitrate hexahydrate, zinc sulfate, titanium tetrachloride, tetraisopropyl titanate, titanium acetylacetonate, titanium lactate, zirconium acetylacetate , Zirconyl acetate, zirconyl sulfate, ammonium zirconium carbonate, zirconyl stearate, zirconyl octylate, zirconyl nitrate, zirconium oxychloride, zirconium zirconium chloride, chromium acetate, chromium sulfate, magnesium sulfate, magnesium chloride hexahydrate, magnesium citrate Nine hydrate, sodium phosphotungstate, sodium tungsten citrate, 12 tungstophosphoric acid n hydrate, 12 tungstosilicic acid 26 hydrate, molybdenum chloride, 12 molybdophosphoric acid n hydrate, gallium nitrate , 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 inorganic mordants, aluminum-containing compounds, titanium-containing compounds, zirconium-containing compounds, and group IIIB series metal compounds (salts or complexes) of the periodic table are preferable.
The addition amount in the ink receiving layer of the mordant is preferably ^{0.01~5g / m 2, 0.1~3g / m} 2 is more preferable.

-Other ingredients-
In addition to the above components, the ink-receiving layer or the coating solution for forming the ink-receiving layer (ink-receiving layer coating solution) may further include various known additives such as ultraviolet absorbers and antioxidants as necessary. Agent, optical brightener, monomer, polymerization initiator, polymerization inhibitor, anti-bleeding agent, preservative, viscosity stabilizer, antifoaming agent, surfactant, antistatic agent, matting agent, anti-curl agent, water resistance agent Etc. can be contained.

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

  Further, for the purpose of improving the dispersibility of the inorganic fine particles, the inorganic surface may be treated with a silane coupling agent. The silane coupling agent includes 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 a coupling treatment site. Those having the following are preferred.

  In the present invention, an embodiment in which the ink receiving layer coating solution contains a surfactant is preferred. Surfactants here include any of cationic, anionic, nonionic, amphoteric, fluorine, and silicon surfactants.

  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, polyoxyalkylene ether) Ethylene nonylphenyl ether), oxyethylene / oxypropylene block copolymer, sorbitan fatty acid esters (for example, sorbitan monolaurate, sorbitan monooleate, sorbitan trioleate, etc.), polyoxyethylene sorbitan fatty acid esters (for example, polyoxyethylene) Sorbitan monolaurate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitant Oleate, etc.), polyoxyethylene sorbitol fatty acid esters (eg, polyoxyethylene sorbitol tetraoleate), glycerin fatty acid esters (eg, 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), and the like. Sharp emission 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 total amount of the surfactant in the ink-receiving layer coating solution is preferably 0.001 to 2.0%, more preferably 0.01 to 1.0%.

  The ink-receiving layer is formed by applying a coating solution containing fine particles and a water-soluble resin to the support surface to form a coating layer, and further adding a crosslinking agent to the coating solution and / or the following basic solution, and ( 1) at the same time when the coating solution is applied to form a coating layer, or (2) during the drying of the coating layer formed by coating the coating solution and before the coating layer exhibits reduced-rate drying, In any case, it is preferably formed by a method (Wet-on-Wet method) in which a basic solution having a pH of 7.1 or higher is applied to the coating layer and the coating layer is crosslinked and cured. Here, the crosslinking agent capable of crosslinking the water-soluble resin is preferably contained in at least one or both of the coating solution and the basic solution. Providing the ink-receiving layer crosslinked and cured in this manner is preferable from the viewpoint of ink absorbability and prevention of film cracking.

  The mordant is desirably present so that the thickness of the mordant-existing portion from the surface of the receptor layer is 10 to 60% of the receptor layer thickness. For example, (1) a method of forming a coating layer containing the fine particles, a water-soluble resin, and a crosslinking agent, and applying a mordant-containing solution thereon, (2) a coating solution containing the fine particles, a water-soluble resin, and a mordant-containing solution. It can be formed by any method such as a method of applying multiple layers. The mordant-containing solution may contain inorganic fine particles, a water-soluble resin, a crosslinking agent, and the like.

  As described above, since a large amount of mordant is present in a predetermined part of the ink receiving layer, the ink-jet coloring material is sufficiently mordanted, color density, aging blur, gloss of printed part, and water resistance of characters and images after printing. This is preferable because ozone resistance is improved. Part of the mordant may be contained in the layer initially provided on the support, and in that case, the mordant to be applied later may be the same or different.

  In the present invention, the ink-receiving layer coating liquid (first liquid) containing fine particles (for example, vapor phase silica) and a water-soluble resin (for example, polyvinyl alcohol) can be prepared, for example, as follows. . That is, fine particles of vapor phase method silica or the like are added to water together with a dispersant or the like (for example, silica fine particles in water are 10 to 20% by mass), pre-dispersed (primary dispersion) with a homomixer or the like, and then obtained. The dispersion is further dispersed (secondary dispersion) in, for example, one pass using a disperser such as an optimizer (manufactured by Sugino Machine Co.), and then an aqueous polyvinyl alcohol (PVA) solution (for example, 1 To a PVA with a mass of about / 3). In order to impart stability to the coating solution, it is preferable to adjust the pH to about 9.2 with aqueous ammonia or the like, or to use a dispersant. The obtained coating liquid is in a uniform sol state, and a porous ink-receiving layer having a three-dimensional network structure can be formed by coating this on a support by the following coating method and drying it.

  As the disperser used for dispersion, various conventionally known dispersers such as a colloid mill disperser, a high-speed rotating disperser, a medium stirring disperser (ball mill, sand mill, etc.), an ultrasonic disperser, and a high-pressure disperser are used. be able to. Among these, an ultrasonic disperser or a high-pressure disperser (particularly a high-pressure jet disperser) is preferable from the viewpoint of effectively dispersing the formed fine particles.

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

Furthermore, a chaotic polymer can be used as the dispersant. Examples of the chaotic polymer include the aforementioned mordants. It is also preferable to use a silane coupling agent as the dispersant.
The amount of the dispersant added to the fine particles is preferably 0.1 to 30% by mass, and more preferably 1 to 10% by mass.

  The ink receiving layer coating solution is applied by a known coating method using, for example, an extrusion die coater, an air doctor coater, a bread coater, a rod coater, a knife coater, a squeeze coater, a reverse roll coater, a bar coater, or the like. Can do.

  A basic solution (second liquid) is applied to the coating layer at the same time as or after the coating of the ink receiving layer coating liquid (first liquid), and the second liquid is applied to the coating layer after coating. You may give before it comes to show decremental drying. That is, after the application liquid for the ink receiving layer (first liquid) is applied, the second liquid is introduced while the applied layer exhibits constant rate drying. This second liquid may contain a mordant.

  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 application of the first liquid, the coating layer is dried until the coating layer exhibits a reduced rate of drying. This drying is generally performed at 40 to 180 ° C. for 0.5 to 10 minutes (preferably, 0 .5-5 minutes). The drying time naturally varies depending on the coating amount, but usually the above range is appropriate.

  As a method to give before the coating layer which consists of said 1st liquid comes to show a decreasing rate drying rate, (1) The method of further apply | coating 2nd liquid on a coating layer, (2) By methods, such as a spray The method of spraying, (3) The method of immersing the support body in which this application layer was formed in the 2nd liquid, etc. are mentioned.

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

  After application | coating of a 2nd liquid, generally it heats at 40-180 degreeC for 0.5 to 30 minutes, and drying and hardening are performed. Especially, it is preferable to heat at 40-150 degreeC for 1 to 20 minutes.

  Further, when the basic solution (second liquid) is applied simultaneously with the application of the ink-receiving layer coating liquid (first liquid), the first liquid and the second liquid are brought into contact with the support. Thus, the ink receiving layer can be formed by simultaneously coating (multilayer coating) on the support, 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 coating, the formed coating layer is dried. In this case, the drying is generally performed by heating the coating layer at 40 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 at the same time are close to the discharge port of the extrusion die coater, that is, before moving onto the support. A multilayer is formed, and in that state, the multilayer is applied on the support. Since the two-layer coating liquid that has been layered before coating is likely to cause a crosslinking reaction at the interface between the two liquids when transferred to the support, the two liquids to be discharged 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 mentioned above, it is preferable to apply a triple layer coating with a barrier layer solution (intermediate layer solution) interposed between the two solutions together with the application of the first solution and the second solution.

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

  After the ink receiving layer is formed on the support, the ink receiving layer is subjected to, for example, super calender, gloss calender, etc., and is subjected to calender treatment through the roll nip under heat and pressure, so that surface smoothness, glossiness, It is possible to improve transparency and coating strength. However, the calendar process may cause a decrease in the porosity (that is, the ink absorptivity may be decreased), so it is necessary to set conditions under which the decrease in the porosity is small.

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

The layer thickness of the ink receiving layer needs to be determined in relation to the void ratio in the layer since it needs to have an absorption capacity sufficient to absorb all droplets when used for inkjet recording. For example, when the ink amount is 8 nL / mm ² and the porosity is 60%, the layer thickness is preferably about 15 μm or more.
Considering this point, when used for inkjet recording, the thickness of the ink receiving layer is preferably 10 to 50 μm.

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

In addition, 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 support is preferably 30% or less, More preferably, it is 20% or less.
The haze value can be measured using a haze meter (HGM-2DP: Suga Test Instruments Co., Ltd.).

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

[Support]
When the support of the ink jet recording medium in the present invention is composed of a base paper, the base paper is obtained by papermaking a pulp stock obtained by beating desired pulp, in particular, beating and prepared pulp slurry. In the paper making process for making paper, the web layer side corresponding to the surface on which the recording layer of the base paper is coated, for example, is dried by pressing the dryer canvas against the drum dryer cylinder. In this process, the dryer canvas Can be dried within the range of 1.5 to 3 kg / cm.

  The pulp is not particularly limited, and natural pulp selected from conifers, hardwoods, etc., for example, LBKP (hardwood bleached kraft pulp) such as aspen, acacia, maple, poplar, eucalyptus, spruce, Douglas It can be appropriately selected from NBKP (softwood bleached kraft pulp) such as fur material, LBSP, NBSP, LDP, NDP, LUKP, NUKP and the like. These can be used alone or in combination of two or more, in addition to being used alone.

  The form of the pulp constituting the base paper is preferably 30% by mass or more of kraft pulp made of maple (maple material LBKP), more preferably 50% by mass or more of maple material LBKP. When the blending amount of the maple material LBKP in the pulp is 30% by mass or more, the smoothness of the support is improved and the glossiness is further improved.

  The manufacturing method of said kraft pulp (LBKP) is not specifically limited, The manufacturing method of a normal kraft pulp can be used widely. The kraft pulp is beaten so that the water retention is within a predetermined range, and then a sizing agent is added to the pulp as necessary to prepare a pulp slurry, and the prepared pulp slurry is paper-made. In addition, when setting it as multiple types of mixed pulp, while beating and preparing a certain kraft pulp, beating and preparing other pulp separately from this kraft pulp, both are mixed.

  When making paper, the freeness after beating LBKP is preferably 200 to 400 ml in accordance with the Canadian Standard Freeness (CSF). When the freeness is in the above range, the swelling / shrinkage rate is small, and good flatness (surface smoothness) can be obtained. The freeness is a value measured in accordance with the Canadian Standard Test Method in “Pulp Freeness Test Method” of JIS-P8121.

  The water retention after beating is preferably 100 to 200%. When the water retention of the pulp after beating constituting the pulp stock before papermaking is in the above range, the pulp has a low expansion / shrinkage ratio, high gloss, and smooth surface properties with little unevenness.

  The water retention refers to the JAPAN TAPPI paper pulp test method no. 26: 2000 (pulp-water retention test method). This is due to the method of dewatering the pulp suspension by centrifugal force and measuring the water retention of the pulp after dehydration. Specifically, the beaten pulp suspension is filtered through a suitable filtration cup called a centrifugal cup. After suction filtration in step 1, each container is placed in a settling tube of a centrifuge and centrifuged for a certain period of time under certain conditions, and the dehydrated wet pulp is taken out and weighed. Next, drying is performed at 105 ° C., and the wet pulp after centrifugal dehydration is absolutely dried. Then, the mass of the wet pulp after centrifugal dehydration is A, the mass of the pulp after absolutely dry is B, and the water retention (%) = (A−B) / B × 100.

  As the pulp, it is preferable to use a pulp with few impurities, and it is also useful to use a pulp (bleached pulp) that has been subjected to a bleaching treatment to improve whiteness.

  Among the above, the pulp is preferably a hardwood bleached kraft pulp (bleached LBKP) that has been bleached to improve whiteness in terms of impurities and hue, and among them, aspen, acacia, maple, and poplar Hardwood bleached kraft pulp (bleached LBKP) comprising at least one selected from the above is particularly preferred. Each of these bleaching LBKPs may be used alone or as a mixed pulp in which two or more kinds of bleaching LBKP are mixed, or one or two or more kinds of bleaching LBKP and one or more kinds of other pulps other than the bleaching LBKP. As the mixed pulp, it can be suitably used.

  The pulp concentration in the base paper according to the present invention, that is, the pulp stock for making the base paper, is preferably 60% by mass or more, and more preferably 80% by mass or more.

  The pulp stock before papermaking can further contain anionic colloidal silica. That is, it is preferable to make paper after the addition of anionic colloidal silica to obtain the base paper according to the present invention. The inclusion of anionic colloidal silica is effective in improving the sharpness when cutting, that is, the cutting suitability, in addition to the ability to enhance dehydration (that is, function as a drainage aid).

The specific surface area of the anionic colloidal silica is preferably in the range of 100 to 1000 m ² / g, and the average particle diameter is preferably in the range of 1 to 20 nm.

  As content in the case of containing the anionic colloidal silica, 0.005 to 0.5 mass% with respect to the amount of the pulp according to the present invention, in terms of the above-described cutting suitability improvement and dewatering improvement. Preferably, 0.01 to 0.2 mass% is more preferable.

  The paper machine for making the pulp stock is not particularly limited, and can be appropriately selected from conventionally known paper machines. For example, a long paper machine equipped with a shaking device having a vibration amplitude of 10 mm or more can be cited, and a paper machine having a dandy roll (for example, a dandy roll made of 60 to 100 mesh wire) in terms of improving flatness. Is preferred.

  The base paper according to the present invention is a natural pulp paper mainly composed of normal natural pulp, and in the base paper, as additive chemicals, fillers such as clay, talc, calcium carbonate, urea resin fine particles, rosin, Sizing agents such as alkyl ketene dimers, higher fatty acid salts, paraffin wax, alkenyl succinic acid, paper strength enhancers such as starch, polyacrylamide, and polyvinyl alcohol, moisture retention agents such as polyethylene glycols, fixing agents such as sulfuric acid bands, etc. Can be added as appropriate. In addition, white pigments such as dyes and titanium oxide, fluorescent dyes, slime control agents, antifoaming agents, and softening agents such as quaternary ammonium can be added as necessary.

The surface of the base paper made of natural pulp paper can be surface-sized with a film-forming polymer such as gelatin, starch, carboxymethylcellulose, polyacrylamide, polyvinyl alcohol, or a modified product of polyvinyl alcohol. Examples of modified polyvinyl alcohol include carboxyl group-modified products, silanol-modified products, and copolymers with acrylamide. The coating amount of the film-forming polymer in the case of surface sizing by the film-forming polymer is preferably adjusted to ^{0.1~5.0g / m 2, 0.5~2.0g / m} 2 It is more preferable to adjust to. Further, an antistatic agent, a fluorescent brightening agent, a pigment, an antifoaming agent, and the like can be added to the film-forming polymer as necessary.

  The base paper usually has a moisture content of about 7.0% by mass, but in the present invention, considering the texture of the base paper, 7.5 to 10% by mass is preferable, and 8.0 to 10% by mass is more preferable. preferable.

The thickness of the base paper is not particularly limited, and is preferably 150 to 250 μm. The basis weight of the base paper is preferably 150 to 250 g / m ² , and particularly preferably 180 to 220 g / m ^2. .

  The base paper according to the present invention preferably has excellent surface smoothness and flatness in consideration of the case where flatness such as photographic printing paper is desired. From such a viewpoint, a machine calendar, a super calendar, etc. A surface treatment can be performed by applying heat and pressure by applying a calendering treatment to give a higher degree of smoothness.

The density of the base paper is generally 0.7 to 1.2 g / m ² (JIS P-8118). Further, as the stiffness of the base paper, MD (vertical direction) is 1.0 to 3.0 mNm and CD (horizontal direction) is 0.5 to 1.5 mNm under the conditions specified in JIS P-8125 (2000). preferable.

A surface sizing agent may be applied to the surface of the base paper. As the surface sizing agent, the same sizing agent that can be added to the base paper can be used.
Moreover, it is preferable that pH of a base paper is 5-9 by the measured value by the hot water extraction method prescribed | regulated by JISP-8113.

  From the viewpoint of improving the smoothness of the substrate (particularly the base paper), the dispersion of the inorganic fine particles in the coating solution for forming the ink receiving layer is treated using an ultrasonic dispersing machine or a high-pressure dispersing machine (particularly a high-pressure jet dispersing machine). It is also possible to adjust the dispersion state (dispersibility) of the inorganic fine particles. Details of the inorganic fine particles are as described later.

  Specifically, by using an ultrasonic disperser or a high-pressure disperser instead of a disperser using a dispersion such as beads (for example, a bead mill disperser) generally used for dispersion of inorganic fine particles. It can adjust suitably. As the high-pressure disperser, for example, a disperser of a liquid-liquid facing collision type [for example, an optimizer system (manufactured by Sugino Machine Co., Ltd.)] is preferable, and the dispersion treated with this disperser is highly transparent. The ink jet recording medium (especially the ink receiving layer) used has a high glossiness.

  In the dispersion by the ultrasonic disperser, the dispersion is further obtained by applying ultrasonic waves to the pre-dispersed liquid containing inorganic fine particles and preliminarily dispersed. There is no particular limitation as long as ultrasonic irradiation is possible. For example, an ultrasonic disperser UH-600H manufactured by SMT Co., Ltd. can be suitably used.

  In the dispersion by the high-pressure disperser (particularly, the high-pressure jet disperser), the pre-dispersed liquid containing inorganic fine particles and preliminarily dispersed is caused to collide with a liquid-liquid oppositely at a high pressure, or is passed through an orifice at a high pressure. To further disperse to obtain a dispersion. There is no particular limitation as long as it is an aspect capable of opposing collision at high pressure or passage to the orifice, and a commercially available device generally called a high pressure homogenizer can be suitably used.

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

  The high-pressure disperser is basically an apparatus composed of a high-pressure generating unit for pressurizing raw material slurry and the like, and a liquid-liquid facing collision unit or an orifice unit. As the high-pressure generator, a high-pressure pump generally called a plunger pump is suitable, and the high-pressure pump includes various types such as a series type, a double type, a triple type, and any type is particularly limited. It is applicable.

  Examples of the high-pressure disperser include a nanomizer manufactured by Nanomizer, a microfluidizer manufactured by Microfluidics, and an optimizer manufactured by Sugino Machine.

  The processing pressure when the liquid-liquid facing collision is performed at a high pressure is preferably 50 MPa or more, more preferably 100 MPa or more, and particularly preferably 130 MPa or more. Further, the differential pressure between the orifice inlet side and the outlet side when passing through the orifice is preferably 50 MPa or more, more preferably 100 MPa or more, and particularly preferably 130 MPa or more, like the treatment pressure.

In any case, since the dispersion efficiency depends on the processing pressure, the higher the processing pressure, the higher the dispersion efficiency. However, the upper limit of the processing pressure is 350 MPa. When it is less than 350 MPa, it is preferable in terms of pressure resistance such as piping of a high-pressure pump and durability of the apparatus.
Moreover, there is no restriction | limiting in particular in the frequency | count of a process, Usually, it selects suitably in the range of 1 to several dozen times.

When preparing a dispersion, various additives can be added.
Examples of additives include nonionic or cationic surfactants (anionic surfactants are not preferred for forming aggregates), antifoaming agents, nonionic hydrophilic polymers (polyvinyl alcohol, polyvinylpyrrolidone). , 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 can be mentioned, and can be appropriately added as necessary.

  The water-miscible organic solvent is particularly preferable in terms of suppressing the formation of fine lumps when inorganic fine particles (particularly gas phase method silica) are pre-dispersed. The content of the dispersion is preferably 0.1 to 20% by mass, particularly preferably 0.5 to 10% by mass.

  In addition, the pH when preparing a dispersion of inorganic fine particles (particularly gas phase method silica) can vary widely depending on other components such as the type of inorganic fine particles (particularly gas phase method silica) and various additives, Generally it is the range of 1-8, and the range of 2-7 is especially preferable.

  When preparing a dispersion of inorganic fine particles, the average primary particle size of the inorganic fine particles is preferably 30 nm or less, more preferably 20 nm or less, still more preferably 10 nm or less, and particularly preferably 3 to 10 nm. Furthermore, from the viewpoint of giving glossiness, the average primary particle size of the inorganic fine particles is 30 nm or less, and the secondary particle size of the inorganic fine particles in the dispersion after dispersion is 200 nm or less (more preferably 150 nm or less, particularly Preferably it is 120 nm or less.

  In addition to the additives, a mode in which a water-soluble organic cation compound and / or a water-soluble polyvalent metal compound is added and dispersed using the above-described disperser according to the present invention is also suitable.

<Water-soluble organic cation compound>
The inorganic fine particles are preferably used in a state of being predispersed before dispersion. In this case, it is possible to suitably perform dispersion by containing at least one water-soluble organic cation compound as a dispersant (aggregation inhibitor).

  Although there is no restriction | limiting in particular in a water-soluble organic cation compound, The example of the mordant mentioned later etc. Water-soluble organic cation compound which has a primary-tertiary amino group, a quaternary ammonium base, or a phosphonium base (These Salt) are 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 polydiallylamine derivative as a constituent unit is particularly preferable, and this can be obtained by cyclocondensation of a diallylamine compound. Examples of commercially available products include Charol DC902P (Daiichi Kogyo Seiyaku Co., Ltd.), Jetfix 110 (Satoda Kako Co., Ltd.), Unisense CP-101 to 103 (Senka Co., Ltd.), PAS-H (Nittobo Co., Ltd.), and the like. It is done.

  The amount of the water-soluble organic cation compound is preferably 1 to 10% by mass and more preferably 1 to 5% by mass with respect to the inorganic fine particles. When the amount increases, as described above, the gelation ability after coating decreases depending on the type of vapor phase silica.

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. Among them, dimethyl diallyl ammonium chloride, monomethyl diallyl ammonium chloride and polyamidine are preferable, and dimethyl diallyl ammonium chloride and monomethyl ammonium chloride are particularly preferable in terms of water resistance. A water-soluble organic cation compound may be used individually by 1 type, or may use 2 or more types together.

  The content 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 inorganic fine particles.

  The water-soluble organic cation compound may be added to the dispersion medium before adding the inorganic fine particles, or may be added during the preliminary mixing or after the dispersion is completed. In view of obtaining a more stable dispersion, it is particularly preferred to add it to the dispersion medium before adding the inorganic fine particles.

<Water-soluble polyvalent metal compound>
The water-soluble organic cation compound can be used in the dispersion without using or using at least one water-soluble polyvalent metal compound.

  The water-soluble polyvalent metal compound may be added to the dispersion medium, or may be added during premixing or after the completion of dispersion. In view of obtaining a more stable dispersion, it is preferable to add it to the dispersion medium before adding the inorganic fine particles.

The water-soluble polyvalent metal compound 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.
Specific examples include calcium acetate, calcium chloride, calcium formate, calcium sulfate, calcium butyrate, barium acetate, barium sulfate, barium phosphate, barium oxalate, barium naphthoresorcin carboxylate, barium butyrate, manganese chloride, manganese acetate, Manganese formate dihydrate, manganese ammonium sulfate hexahydrate, cupric chloride, ammonium copper (II) chloride dihydrate, copper sulfate, copper (II) butyrate, copper oxalate, copper phthalate, copper citrate , Copper gluconate, 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, “water-soluble” in a water-soluble polyvalent metal compound means that 1% by mass or more dissolves in water at 20 ° C.

  Of the above water-soluble polyvalent metal compounds, compounds of aluminum or Group 4A metals (for example, zirconium, titanium) of the periodic table are preferable. Particularly preferred is a water-soluble aluminum compound. Examples of the water-soluble aluminum compound include inorganic salts such as aluminum chloride or a hydrate thereof, aluminum sulfate or a hydrate thereof, ammonium alum, and the like. Aluminum compounds are preferred.

The basic polyaluminum hydroxide compound has a main component represented by the following general formula 1, 2 or 3, for example, [Al ₆ (OH) ₁₅ ] ³⁺ , [Al ₈ (OH) ₂₀ ] ⁴⁺ , [Al ₁₃ (OH ) ₃₄ ] ⁵⁺ , [Al ₂₁ (OH) ₆₀ ] ³⁺ , and the like, and water-soluble polyaluminum hydroxide containing a basic and high-molecular polynuclear condensed ion stably.
_{[Al 2 (OH) n Cl} 6-n] m ··· Formula 1
[Al (OH) ₃ ] _n AlCl ₃ ... General formula 2
Al _n (OH) _m Cl _{(3 nm)} [0 <m <3n]... General 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 Hakone Co., Ltd. to HAP. The name is -25, which is Alphain 83 from Daimei Chemical Co., Ltd. and is also marketed by other manufacturers for the same purpose, and various grades are easily available.

  Preferable examples of the water-soluble polyvalent metal compound containing Group 4A metal of the periodic table include water-soluble compounds containing titanium or zirconium. Examples of the water-soluble compound containing titanium include titanium chloride and titanium sulfate. Water-soluble compounds containing zirconium include zirconium acetate, zirconium chloride, zirconium oxychloride, hydroxy zirconium chloride, zirconium nitrate, basic zirconium carbonate, zirconium hydroxide, zirconium lactate, zirconium carbonate / ammonium, zirconium carbonate / potassium, zirconium sulfate. And zirconium fluoride compounds.

  The content of the water-soluble polyvalent metal compound in the ink receiving layer is preferably in the range of 0.1 to 10% by mass and more preferably in the range of 0.5 to 8% by mass with respect to the inorganic fine particles.

  The dispersion medium used for dispersing the inorganic fine particles is preferably water or a mixed solvent of water and a small amount of an organic solvent (a low-boiling solvent such as a 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.

  Pre-mixing (premixing, pre-dispersion) before dispersion by the high-pressure disperser or ultrasonic disperser can be performed by ordinary propeller stirring, turbine stirring, homomixing stirring, or the like. As described above, a high-pressure disperser (particularly a high-pressure jet disperser), an ultrasonic disperser, or the like is used for the secondary dispersion.

  Further, from the viewpoint of increasing the concentration of the inorganic fine particles in the dispersion liquid, a method of adding the inorganic fine particles stepwise is preferable.

In the present invention, the liquid temperature when premixing or predispersing as the primary dispersion is not particularly limited, and is preferably 30 ° C. or less, particularly in that a slurry of inorganic fine particles (particularly silica fine particles) can be stably prepared. 25 degrees C or less is preferable. In this case, the dispersion medium before adding the inorganic fine particles may be kept at 20 ° C. or lower, or may be cooled to 20 ° C. or lower by cooling during the preliminary mixing.
In addition, it is preferable to inject into the disperser in a state where the temperature of the slurry of the inorganic fine particles is 20 ° C. or lower, and further 15 ° C. or lower from the viewpoint of obtaining a more stable dispersion.

  The time after preparation of the dispersion and / or the coating liquid for forming the ink receiving layer (ink receiving layer coating liquid) is preferably 5 hours or more, more preferably 8 hours from the viewpoint of stabilizing the coated surface. That's it. The upper limit is not limited and may be several days to several tens of days. The temperature over time is about 10 ° C to about 40 ° C, preferably about 15 ° C to about 35 ° C. The inorganic fine particles may be gently stirred over time so as not to settle.

From the viewpoint of the stability of the coating solution, it is also preferable to apply a heat treatment at 45 ° C. or lower between the end of dispersion of the inorganic fine particles and the application of the coating solution for the ink receiving layer, and then apply after the heat treatment. In particular, the inorganic fine particle dispersion was subjected to a heat treatment at 30 to 48 ° C., preferably 40 to 45 ° C. for about 120 minutes or longer (no upper limit, but preferably about 1 hour or longer and about 24 hours or shorter). Thereafter, it is preferable to prepare and apply a coating liquid for the ink receiving layer.
Furthermore, a mode in which the dispersion of inorganic fine particles is aged for 5 hours or more and combined with heat treatment is particularly preferable.

  The inkjet recording medium in the present invention is prepared by dispersing the inorganic fine particle dispersion prepared as described above, or a hydrophilic binder such as the dispersion, polyvinyl alcohol, a crosslinking agent of the hydrophilic binder, a surfactant, and a water dispersibility. After preparing a coating solution for an ink receiving layer by mixing a cationic resin, etc., any one of these is applied as a coating solution to a substrate (support) such as paper, polyolefin resin-coated paper, or plastic resin film. Can be manufactured.

When the dispersion is prepared as described above, the concentration of the inorganic fine particles in the dispersion is appropriately about 10 to 40% by mass, and preferably 15 to 35% by mass.
The concentration of inorganic fine particles (particularly silica fine particles) in the ink-receiving layer coating solution is suitably about 5 to 25% by mass, preferably 8 to 20% by mass. The amount of inorganic fine particles in the ink receiving layer is preferably in the range of 5 to 30 g / m ² .

  The ink jet recording medium in the present invention is preferably used by dissolving a water-soluble resin, a surfactant, and a water-soluble organic solvent having a boiling point of 150 ° C. or more in an aqueous solution (aqueous medium).

  In addition, in terms of enhancing the apparent surface characteristics and texture when the base material (support) is composed of a base paper, the paper ground index is also important, and the base paper in the present invention has a ground index value. It is preferably composed of 60 or more papers.

  The texture index indicates that the larger the value, the better the texture, and by making the texture index value particularly in the above range, there is no texture unevenness, the smoothness is uniform and high, It is possible to enhance the texture.

In other words, when the formation index value is less than 60, the occurrence of uneven formation becomes remarkable, and the surface uniformity and texture may be inferior. As a result, when an image recording material is constructed, the formability of a photographic-like high-quality image is impaired.
The formation index value is preferably 70 or more.

  The formation index value is M / K Systems, Inc. A 3D sheet analyzer (M / K950) manufactured by (MKS) was used, and the aperture of the analyzer was 1.5 mm in diameter and measured using a micro formation tester (MFT).

  That is, a sample is mounted on a rotating drum in a 3D sheet analyzer, and a local basis weight difference in the sample is determined by a light source mounted on the drum shaft and a photodetector mounted on the outside of the drum corresponding to the light source. Measure as light intensity difference. The measurement target range at this time is set by the diameter of the diaphragm attached to the light incident part of the photodetector. Next, the light intensity difference (deviation) is amplified, A / D converted, classified into 64 photometric basis weight classes, and 100,000 pieces of data are taken in one scan, and the histogram frequency for that data is taken. Get. Then, the highest frequency (peak value) of the histogram is divided by the number of classes having a frequency of 100 or more among those classified into classes corresponding to 64 micro basis weights, and the divided value is set to 1/100. The value is calculated as the formation index value.

  As a method of increasing the formation index value, that is, improving the texture of the base paper, for example, a screen or a vortex cleaner is installed in front of the head box of the paper machine so that the flow direction of the base paper raw material is not constant. Or a method of managing the flocculation of the raw material using additive chemicals such as a dispersant, a texture control additive, a retention and a drainage aid. However, it is not limited to these methods.

  The base paper constituting the ink jet recording medium of the present invention may be suitably configured by providing a polyolefin resin so that at least the surface on which the ink receiving layer is formed (that is, one side or both sides of the base paper) is covered. it can.

The layer thickness of the polyolefin resin on the side where the ink receiving layer is formed is preferably in the range of 20 to 60 μm. More preferably, it is 35-60 micrometers. When the layer thickness is in this range, a photographic texture with a good gloss can be obtained, which is effective in improving productivity and reducing costs.
Especially, the aspect which made the layer thickness the range of 40-55 micrometers is preferable.

  When a polyolefin resin layer is provided on the surface of one side or both sides of the base paper, that is, in the production of a support coated with a resin such as a support for photographic paper, there are melt extrusion, wet lamination, and dry lamination. Melt extrusion is most preferred. When the polyolefin resin layer is formed by melt extrusion, the base paper is pretreated before the polyolefin resin layer is melt-extruded onto the base paper in order to strengthen the adhesion between the base paper and the polyolefin resin layer. Is preferred. For example, a polyolefin resin extruded from an extrusion die on a running base paper is formed by forming a resin film so that the base paper is covered at the nip point between the nip roller and the cooling roller, and by niping and pressing. An extrusion laminating method (also referred to as an extrusion coating method) in which a resin film is laminated on a base paper is widely adopted.

  Examples of the pretreatment include an acid etching treatment using a mixed solution of chromic sulfate, a flame treatment using a gas flame, an ultraviolet irradiation treatment, a corona discharge treatment, a glow discharge treatment, and an anchor coat treatment such as an alkyl titanate, which can be freely selected. In particular, corona treatment is preferable from the viewpoint of simplicity. In the case of corona treatment, it is necessary to treat so that the contact angle with water is 70 ° or less.

  Known examples of the anchor coating agent include organic titanium, isocyanate (urethane) polyethyleneimine, polybutadiene, and the like. Specifically, as the organic titanium system, alkyl titanates such as tetraisopropyl titanate, tetrabutyl titanate and tetrastearyl titanate, titanium acylates such as butoxytitanium stearate, titanium chelates such as titanium acetylacetonate, etc. are known. Yes. Further, as the isocyanate type (urethane type), toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HMDI), xylylene diisocyanate (XDI), isophorone diisocyanate (IPDI) and the like are known.

  Particularly in the present invention, in the case of the extrusion laminating method, after the polyolefin resin is melt-extruded on the base paper, it is preferably passed through an elastic roll having a nip pressure of 2 MPa or more and a cooling roll to perform lamination. A resin layer can be formed.

In other words, fine pores (hereinafter referred to as “craters”) may be formed on the surface of the resin film laminated on the base paper. However, when the number of craters is large, the appearance is not only impaired, but also glossiness is exhibited. Product value is significantly reduced due to the decline. The occurrence of this crater is due to the influence of the entrained air generated when the cooling roller rotates, and the entrained air accumulates in the area between the resin film and the cooling roller, causing a concave dent in the resin film. ing. The smaller the nip pressure between the elastic roll and the cooling roll, and the greater the line speed during lamination, the thinner the resin film, the lower the resin discharge temperature from the extrusion die, and the base paper The rougher the surface roughness, the more likely the craters are generated.
Therefore, by setting the nip pressure between the elastic roll and the cooling roll to 2 MPa or more, generation of craters can be suppressed, and smooth and smooth flatness can be ensured. Preferably, the nip pressure is 3 MPa or more, and the upper limit is 8 MPa.

As the polyolefin resin provided on the base paper, for example, an α-olefin homopolymer such as polyethylene and polypropylene, a mixture of these various polymers, or a random copolymer of ethylene and vinyl alcohol is preferable.
As the polyethylene, for example, LDPE (low density polyethylene), HDPE (high density polyethylene), and L-LDPE (linear low density polyethylene) can be used alone or in combination. When using polyethylene, the melt flow rate before processing is a value measured according to JIS 7201, and preferably 1.2 to 12 g / 10 min.

  In the case where a polyolefin layer made of polyolefin (for example, polyethylene), for example, a polyethylene layer, is provided, the polyethylene layer on the side on which the ink receiving layer of the base paper is formed is generally widely used for photographic printing. As is done with paper, it is preferable to add rutile or anatase type titanium oxide, fluorescent whitening agent, ultramarine to polyethylene to improve opacity, whiteness and hue. Here, as a titanium oxide content, about 3-20 mass% is preferable with respect to polyethylene, and 4-13 mass% is more preferable.

  Further, an undercoat layer can be provided on the polyolefin layer for the purpose of imparting adhesion to an ink receiving layer responsible for image recording. As the undercoat layer, aqueous polyester, gelatin and polyvinyl alcohol (PVA) are preferable, and the thickness of the undercoat layer is preferably from 0.01 to 5 μm.

  The base paper according to the present invention has a polyolefin resin-coated paper (for example, polyethylene-coated paper) when at least a part of the surface on one side on which the ink receiving layer is formed or each surface on both sides is coated with polyolefin (for example, polyethylene). Paper) and can be used as glossy paper. When a polyolefin such as polyethylene is melt-extruded onto a base paper and coated, a so-called molding process is performed so that it can be obtained with ordinary photographic printing paper. It can also be used as a support in the form of a smooth matte surface or silky surface.

  A back coat layer may be provided on the surface of the base paper constituting the ink jet recording medium of the present invention on the side opposite to the side on which the ink receiving layer is formed. This back coat layer can be constituted by adding and containing a white pigment, an aqueous binder, and other components.

  Examples of white pigments that can be added to 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 silicic acid. White inorganic pigments such as aluminum, 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, Examples thereof include organic pigments such as styrene plastic pigment, acrylic plastic pigment, polyethylene, microcapsule, urea resin, and melamine resin.

  Examples of the aqueous binder that can be added to the backcoat layer include styrene / maleate copolymer, styrene / acrylate copolymer, polyvinyl alcohol, silanol-modified polyvinyl alcohol, starch, cationized starch, casein, gelatin, Examples thereof include water-soluble polymers such as carboxymethyl cellulose, hydroxyethyl cellulose and polyvinyl pyrrolidone, and water-dispersible polymers such as styrene butadiene latex and acrylic emulsion.

  Examples of other components that can be added to the backcoat layer include an antifoaming agent, an antifoaming agent, a dye, a fluorescent brightening agent, an antiseptic, and a water-proofing agent.

<Water-based ink>
The water-based ink (hereinafter also simply referred to as “ink”) in the present invention is characterized by containing a color material and having an pH of 9 or more.

The aqueous ink in the present invention needs to have a pH of 9 or more in order to suppress bronzing, preferably has a pH of 9.3 or more, and more preferably has a pH of 9.5 or more. From the viewpoint of controlling bronze, the higher the pH, the better.
By applying water-based ink having a pH of 9 or more to the ink jet recording medium of the present invention and recording, the formed image is excellent with suppressed bronzing.
The pH of the water-based ink can be adjusted to 9 or more by using a known pH adjusting agent.

(Color material)
As the coloring material in the present invention, a dye or a pigment can be used, and among these, a pigment is preferable from the viewpoint of the storage stability of the ink.

  As the dye, a general dye that can be used for inkjet can be used. Examples include colorants classified as oil-soluble dyes, basic dyes, etc. in addition to those classified as acid dyes, direct dyes, reactive dyes, vat dyes, sulfur dyes or food dyes in the color index. You can also.

  In addition, as a pigment for black ink, carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black and channel black, or copper oxide, iron oxide (CI pigment) Examples include black 11), metals such as titanium oxide, and organic pigments such as aniline black (CI Pigment Black 1). However, carbon black is preferable because it has a relatively low density and does not easily settle in water.

  For color inks, C.I. I. Pigment Yellow 1 (Fast Yellow G), 3, 12 (Disazo Yellow AAA), 13, 14, 17, 24, 34, 35, 37, 42 (Yellow Iron Oxide), 53, 55, 74, 81, 83 (Disazo Yellow HR), 93, 94, 95, 97, 98, 100, 101, 104, 108, 109, 110, 117, 120, 128, 138, 153, 180, C.I. I. Pigment Red 1, 2, 3, 5, 17, 22 (Brilliant First Scarlet), 23, 31, 38, 48: 2 (Permanent Red 2B (Ba)), 48: 2 (Permanent Red 2B (Ca)), 48 : 3 (Permanent Red 2B (Sr)), 48: 4 (Permanent Red 2B (Mn)), 49: 1, 52: 2, 53: 1, 57: 1 (Brilliant Carmine 6B), 60: 1, 63: 1, 63: 2, 64: 1, 81 (Rhodamine 6G rake), 83, 88, 101 (Bengara), 104, 105, 106, 108 (Cadmium red), 112, 114, 122 (Quinacridone magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 185, 190, 193, 202, 206, 09,219, C. I. Pigment violet 19, 23, C.I. I. Pigment orange 36, C.I. I. Pigment Blue 1, 2, 15 (phthalocyanine blue R), 15: 1, 15: 2, 15: 3 (phthalocyanine blue G), 15: 4, 15: 6 (phthalocyanine blue E), 16, 17: 1, 56 , 60, 63, C.I. I. Pigment Green 1, 4, 7, 8, 10, 17, 18, 36, etc. can be used.

  As described above, various dyes and pigments can be used as the colorant, but more preferably, when dispersed using a polymer, when the dye is infiltrated into the polymer, or when fine polymer particles are used. This is a case of coexistence with a polymer.

  As described above, when a pigment is used as the coloring material in the present invention, the glass transition temperature of the polymer used for dispersing the pigment is preferably 50 ° C. or lower. This is because when the glass transition temperature exceeds 50 ° C., the fixing property on plain paper or glossy paper is deteriorated. When the EO adduct and / or PO adduct of 2,2-dibutyl-1,3-propanediol that can be removed by the ink in the present invention is used at a glass transition temperature of 50 ° C. or lower, the glass transition is apparently further increased. The temperature is lowered, the overlapping portions of dots on glossy paper are easily fused, and the surface smoothness of the dot surface is improved, so that the glossiness is improved. More preferably, it is the range of 20 degreeC-45 degreeC.

  When the colorant is a pigment, it is dispersed in a solvent using a disperser. In this case, various commercially available dispersers can be used as the disperser, and non-media dispersion is preferred. Specific examples thereof include a wet jet mill (Genus), a nanomer (Nanomer), a homogenizer (Gorin), an optimizer (Sugino Machine), and a microfluidizer (Microfluidics).

  The addition amount of the color material contained in the ink in the present invention is preferably 0.5 to 30% by mass, more preferably 1.0 to 15% by mass with respect to the total mass of the ink. If the addition amount is less than 0.5% by mass, the print density cannot be ensured. If the addition amount exceeds 30% by mass, the viscosity of the ink increases and structural viscosity is generated in the viscosity characteristics, and the ejection stability of the ink from the inkjet head. Because it tends to be worse.

(solvent)
In the water-based ink in the present invention, it is preferable to use a solvent other than water in order to disperse the color material.
As the solvent, a known solvent (for example, a water-soluble organic solvent) generally used for water-based inks can be used.
Examples of the water-soluble organic solvent include alcohols, ethers, glycols, ketones, esters, amides, and the like.
Specific examples of the water-soluble organic solvent include glycerin, 3-ethoxy-1,2-propanediol, 1,6-hexanediol, 3-methyl-1,3-butanediol, 4-methyl-1,2 -Pentanediol, 1,2-hexanediol, diethylene glycol, PEG200, etc. as polyethylene glycols, alkylene glycol monoalkyl ethers as ethylene glycol monobutyl ether, propylene glycol monobutyl ether, diethylene glycol monobutyl ether , Triethylene glycol monobutyl ether, triethylene glycol monomethyl ether, etc., glycols such as 2-ethyl-1,3-hexanediol, 2-butyl-2-ethyl-1,3-butanediol, Each Can.
The content of the solvent is preferably 5 to 70% by mass, more preferably 10 to 50% by mass, and particularly preferably 15 to 40% by mass with respect to the total mass of the ink.

Furthermore, as the ink in the present invention, a moisturizer, a dissolution aid, and a permeation control for the purpose of ensuring the standing stability, stable ejection from the inkjet head, improvement of clogging, or prevention of ink deterioration, etc. Add various additives such as chemicals, viscosity modifiers, pH adjusters, dissolution aids, antioxidants, antiseptics, antifungal agents, corrosion inhibitors, chelates to capture metal ions that affect dispersion You can also.

Next, the ink jet recording method of the present invention will be described.
The inkjet recording method of the present invention comprises an ink receiving layer and an outermost surface layer farthest from the support on the side having the ink receiving layer on the support, wherein the outermost surface layer contains alkali-soluble organic fine particles. Recording is performed using a water-based ink having a pH of 9 or more containing a coloring material on a recording medium.
Here, the ink jet recording medium and the water-based ink are as described above.

  The inkjet recording method of the present invention has the effect of remarkably improving bronzing by applying an aqueous ink having a pH of 9 or more containing a coloring material (inkjet recording) to an inkjet recording medium containing alkali-soluble organic fine particles. Can play.

In the ink jet recording method of the present invention, a method of applying the water-based ink to the ink jet recording medium uses a jetting method using an ink jet nozzle. Thereby, the outstanding effect of this invention can be exhibited notably.
There is no restriction | limiting in particular as said inkjet nozzle, A well-known nozzle can be suitably selected according to the objective.

A method of jetting by the ink jet nozzle (ink jet recording method) will be described below.
In the present invention, for example, a charge control method that ejects ink using electrostatic attraction, a drop-on-demand method (pressure pulse method) that uses the vibration pressure of a piezo element, and an electric signal is converted into an acoustic beam into ink. Known systems such as an acoustic ink jet system that irradiates and discharges ink using radiation pressure, and a thermal ink jet (bubble jet (registered trademark)) system that uses ink to form bubbles by heating ink and generate pressure Are preferably used.

The preferred physical properties of the water-based ink applied to the ink jet recording medium by the ink jet recording method of the present invention vary depending on the printing apparatus, but generally, the viscosity at 25 ° C. is preferably 2 to 30 mPa · s, and 3 to 15 mPa · s. s is more preferable.
The surface tension of the water-based ink is preferably 20 to 50 mN / m, and more preferably 25 to 40 mN / m.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, “part” and “%” are based on mass.

(Preparation of ink A1)
The ink was extracted from the ICC-33 cartridge of PX-G920 (Epson), adjusted to pH = 9.7 by adding NaOH aqueous solution, and then filled into the ICC-33 cartridge again.

(Preparation of ink A2)
The ink was taken out from the iPF5000 (Canon) PFI-101C cartridge, and an aqueous NaOH solution was added to adjust the pH to 9.7, and then the PFI-101C cartridge was filled again.

(Preparation of inks A3 and A4)
In the production of the inks A1 and A2, preparation was performed in the same manner except that the pH was set to 9.1 and 9.1, respectively, and filling was performed similarly.

(Preparation of inks A5 and A6)
In the production of the inks A1 and A2, the same preparation was performed except that the pH was 8.5 and 8.3, respectively, and the inks were filled in the same manner.

(Preparation of inkjet recording medium A1 (image receiving layer A1))
-Production of support-
50 parts of maple kraft pulp (LBKP) and 50 parts of acacia kraft pulp (LBKP) were beaten with a double disc refiner to obtain 330 ml of Canadian freeness (Canadian standard freeness).

  Next, the obtained pulp slurry was 1.3% cationic starch (CATO 304L, manufactured by Nippon NSC Co., Ltd.), 0.15% anionic polyacrylamide (DA4104, manufactured by Seiko PMC Co., Ltd.), alkyl per pulp. Ketene dimer (size pine K, manufactured by Arakawa Chemical Co., Ltd.) 0.29%, epoxidized behenic acid amide 0.29%, and polyamide polyamine epichlorohydrin (Arafix 100, manufactured by Arakawa Chemical Co., Ltd.) 0.32% In addition, 0.12% of an antifoaming agent was added thereafter.

The pulp slurry prepared as described above was dehydrated and dried using a long paper machine, and a base paper having a basis weight of 200 g / m ² and a thickness of 190 μm was made to obtain a base paper.
Specifically, in the step of drying by pressing the felt surface of the web through the dryer canvas, the tensile force of the dryer canvas is set to 1.6 kg / cm, and then drying is performed. Polyvinyl alcohol (KL-118, manufactured by Kuraray Co., Ltd.) was applied to both sides so as to be 1.0 g / m ² and dried, and machine calendar treatment was performed.

After performing corona discharge treatment on the wire surface (back surface) side of the obtained base paper, high-density polyethylene is coated to a thickness of 40 μm using a melt extruder to form a polyethylene resin layer consisting of a mat surface (Hereinafter, this polyethylene resin layer side is referred to as “back surface”). After the surface of the polyethylene resin layer on the back side is further subjected to corona discharge treatment, aluminum oxide (antistatic agent; alumina sol 100, manufactured by Nissan Chemical Industries, Ltd.) and silicon dioxide (Snowtex O, Nissan Chemical Industries ( And a dispersion obtained by dispersing in water at a mass ratio of 1: 2 was applied so that the dry mass was 0.2 g / m ² .

  Further, after the corona discharge treatment is performed on the felt surface side (front side) where the polyethylene resin layer is not provided, anatase-type titanium dioxide 10%, a trace amount of ultramarine blue (manufactured by Tokyo Ink), and fluorescence are used using a melt extruder. A white density agent (Whitefloor PSN conc, manufactured by Nippon Chemical Industry Co., Ltd.) 0.08% (vs. polyethylene), MFR (melt flow rate) 3.8 low density polyethylene is extruded to a thickness of 40 μm, A high gloss polyethylene resin layer is formed on the surface side of the base paper so that the nip pressure between the elastic roll and the cooling roll is 3.5 MPa (hereinafter, this high gloss surface is referred to as “front side”). And a support (hereinafter referred to as support A).

  In addition, the elastic body which comprises an elastic roll used the thing whose material is ethylene propylene rubber, hardness is 80 by the value represented by JISK-6301, and thickness is 25 mm. Moreover, the roughness of the roll surface of this elastic roll is 0.3S by the value represented by JISB-0601.

-Preparation of coating solution for ink receiving layer-
(A) Vapor phase silica fine particles, (b) ion-exchanged water, (c) Charol DC-902P and (d) ZA-30 in the following composition were mixed and pre-dispersed using a homomixer. Thereafter, dispersion was further performed at 170 MPa in one pass using a liquid-liquid collision type disperser (Ultimizer, manufactured by Sugino Machine Co., Ltd.). This dispersion was heated to 45 ° C. and held for 20 hours. In addition, (e) an aqueous boric acid solution, (f) a polyvinyl alcohol solution, (g) a surfactant, (h) polyoxyethylene lauryl ether, and (i) ethanol in the following composition at 30 ° C. In addition, an ink-receiving layer coating solution was prepared. At this time, the mass ratio of the silica fine particles to the water-soluble resin [PB ratio = (a) / (f)] is 4.5, and the pH of the coating liquid for the ink-receiving layer after preparation is 3.9, which is acidic. Indicated.

<Composition of coating liquid for ink receiving layer>
(A) AEROSIL 300S F75 ... 10.0 parts [manufactured by Nippon Aerosil Co., Ltd .; gas phase method silica fine particles, average primary particle diameter 7 nm]
(B) Ion-exchanged water ... 64.8 parts (c) Charol DC-902P (51.5% aqueous solution) ... 0.87 parts [Daiichi Kogyo Seiyaku Co., Ltd.]
(D) ZA-30 (Daiichi Rare Element Chemical Co., Ltd.) 0.49 part (e) 5% boric acid aqueous solution 0.40 part (f) Polyvinyl alcohol (water-soluble resin) Solution: 32.0 parts [Composition of solution]
-PVA-235 ... 2.0 parts [manufactured by Kuraray Co., Ltd., saponification degree 88%, polymerization degree 3500]
・ Polyoxyethylene lauryl ether: 0.03 part [Emulgen 109P, manufactured by Kao Corporation]
-The following compound 1 ... 0.12 part- Diethylene glycol monobutyl ether ... 0.55 part [Butisenol 20P, manufactured by Kyowa Hakko Chemical Co., Ltd.]
・ Ion-exchanged water: 26.6 parts (g) Superflex 650: 1.2 parts (Daiichi Kogyo Seiyaku Co., Ltd.)
(H) Polyoxyethylene lauryl ether 0.49 part [Emulgen 109P (10% aqueous solution), HLB value 13.6, manufactured by Kao Corporation]
(I) Ethanol: 2.5 parts

−Preparation of inkjet recording medium−
The front surface of the support obtained above was subjected to a corona discharge treatment, and then the front surface was flowed to 180 ml / m ² in the above-mentioned ink-receiving layer coating solution to a 5-fold diluted aqueous solution of polyaluminum chloride (polyethylene chloride). As aluminum chloride, Alpha-in 83 (Daimei Chemical Co., Ltd.) was applied in-line at a rate of 10.8 ml / m ² . Then, it was dried with a hot air dryer at 80 ° C. (wind speed 3 to 8 m / sec) until the solid content concentration of the coating layer became 20%. At this time, the coating layer showed constant rate drying.
Immediately thereafter, this was immersed in a solution A (pH = 7.8) having the following composition for 30 seconds to adhere 15 g / m ² to the surface of the coating layer, and further dried at 80 ° C. for 10 minutes. As a result, an ink receiving layer having a dry layer thickness of 33 μm was provided.
Furthermore, the outermost surface layer coating solution having the following composition was sequentially applied by a gravure coating apparatus so that the dry solid content was 0.8 g / m ² and dried at 50 ° C. The average secondary particle diameter of silica fine particles using an electron microscope was 80 μm. Thus, an ink jet recording medium having an image receiving layer (outermost surface layer) A1 was produced.

<Composition of Solution A>
(A) Boric acid ... 0.65 part (b) Zircozol AC-7 ... 3.0 part [Daiichi Rare Chemicals Co., Ltd .; Zirconyl ammonium carbonate]
(C) Ammonium carbonate (first grade: manufactured by Kanto Chemical Co., Inc.) 3.5 parts (d) ion-exchanged water 63.3 parts (e) polyoxyethylene lauryl ether 30.0 Part [Emulgen 109P (2% aqueous solution), HLB value 13.6, manufactured by Kao Corporation]

<Composition of outermost surface layer coating liquid A1 (for image receiving layer A1)>
(A) Movinyl S-100A (vinyl acetate copolymer emulsion, manufactured by Nichigo Movinyl Corporation) 100 parts

(Preparation of inkjet recording media A2 to A6 (image receiving layers A2 to A6))
An inkjet recording medium was prepared in the same manner except that the outermost surface layer coating solution was changed as shown in Table 1 in the production of the inkjet recording medium A1.

(Preparation of comparative inkjet recording medium A7 (image receiving layer A7))
In the production of the inkjet recording medium A1, an inkjet recording medium for a comparative example was produced in the same manner except that the outermost surface layer coating solution was not applied.

[Example 1]
Using ink A1 shown in Table 1 below, PX-G920 (Epson) was used to form images on inkjet recording media A1 to A6 having image receiving layers A1 to A6.

[Example 2]
An image was formed on the inkjet recording media A1 to A6 having the image receiving layers A1 to A6 using iPF5000 (Canon) using the ink A2 shown in Table 1 below.

[Example 3]
Using ink A3 shown in Table 1 below, PX-G920 (Epson) was used to form an image on inkjet recording media A1 to A6 having image receiving layers A1 to A6.

[Example 4]
An image was formed on the inkjet recording media A1 to A6 having the image receiving layers A1 to A6 by using iPF5000 (Canon) using the ink A4 shown in Table 1 below.

[Comparative Example 1]
An image was formed on the ink jet recording medium A7 having the image receiving layer A7 by using PX-G920 (Epson) using the ink A1 shown in Table 1 below.

[Comparative Example 2]
Using ink A2 shown in Table 1 below, an image was formed on an inkjet recording medium A7 having an image receiving layer A7 using iPF5000 (Canon).

[Comparative Example 3]
An image was formed on the ink jet recording medium A7 having the image receiving layer A7 by using PX-G920 (Epson) using the ink A3 shown in Table 1 below.

[Comparative Example 4]
Using ink A4 shown in Table 1 below, an image was formed on an inkjet recording medium A7 having an image receiving layer A7 using iPF5000 (Canon).

[Comparative Example 5]
Using ink A5 shown in Table 1 below, images were formed on inkjet recording media A1 to A7 having image receiving layers A1 to A7 using PX-G920 (Epson).

[Comparative Example 6]
An image was formed on the inkjet recording media A1 to A7 having the image receiving layers A1 to A7 by using iPF5000 (Canon) using the ink A6 shown in Table 1 below.

[Evaluation]
Next, the images obtained above were evaluated as follows. The results are shown in Table 1.

<Bronze>
A cyan solid image having the maximum density was printed on the inkjet recording medium obtained above. It observed visually and evaluated according to the following evaluation criteria. The results are shown in Table 1.

~Evaluation criteria~
5: Level that cannot be confirmed.
4: Level that can be confirmed slightly.
3: Acceptable level that can be confirmed but has no practical problem.
2: A level that can be confirmed and causes a practical problem.
1: Level that can be clearly confirmed.

The materials used in the examples and comparative examples are described below.
・ Movinyl S-100A: Vinyl acetate copolymer emulsion, made by Nichigo Movinyl Co., Ltd.
・ Movinyl 206: Vinyl acetate emulsion, manufactured by Nichigo ・ Movinyl Corporation ・ Boncoat EC-2310: Vinyl acetate emulsion, manufactured by Dainippon Ink & Chemicals, Inc. ・ Evadic EV-15: Vinyl acetate-ethylene emulsion, Made by Dainippon Ink & Chemicals, Inc. Boncoat EC-9160: Vinyl acetate-acrylic emulsion, made by Dainippon Ink & Chemicals, Inc.

  As is clear from Table 1, the comparative examples using the comparative ink and the comparative image-receiving layer (outermost surface layer) are all bad with an evaluation of 3 or less, while the examples are all good results. I understood.

Claims (3)

An ink jet recording medium having an ink receiving layer on the support and an outermost surface layer farthest from the support having the ink receiving layer, and containing an alkali-soluble organic fine particle in the outermost surface layer. An ink-jet recording method comprising recording using a water-based ink having a pH of 9 or higher. The inkjet recording method according to claim 1, wherein the alkali-soluble organic fine particles are vinyl acetate copolymer fine particles. The inkjet recording method according to claim 1, wherein the colorant of the water-based ink is a pigment.