JP2010201762A - Method for manufacturing inkjet recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an inkjet recording medium in which bleeding with time is suppressed from occurring under high humidity environment. <P>SOLUTION: In the method for manufacturing the inkjet recording medium, the first liquid containing inorganic fine powder, water soluble resin, and crosslinking agent is coated on a supporting body, and then the second liquid containing amino group-containing basic organic compound, 40 to 90 mass% of which has molecular weights of 700 or less, is applied to form an ink accepting layer (1) simultaneously with the first coating or (2) during drying the coated layer formed by the coating and before the coated layer represents a falling drying rate. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

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

In recent years, an ink jet recording medium having a porous structure in the ink receiving layer has been developed and put into practical use for the purpose of improving the various properties described above. Such an ink jet recording medium has a porous structure, and thus has excellent ink receptivity (fast drying property) and high gloss.
For example, an ink jet recording sheet in which an ink receiving layer containing inorganic fine particles, a water-soluble resin, boric acid, and two or more amino group-containing compounds is provided on a support as being excellent in light resistance and long-term ozone resistance. It has been proposed (see, for example, Patent Document 1).

  On the other hand, an ink jet recording paper contained in an ink receiving layer containing organic particles, inorganic fine particles, acetoacetyl-modified polyvinyl alcohol and tetraethylenepentamine as a cross-linking agent is assumed to have excellent resistance to discoloration and ink absorption without cracking. It is disclosed (for example, see Patent Document 2).

JP 2004-181813 A JP-A-2005-262706

However, the ink jet recording papers described in Patent Documents 1 and 2 are not satisfactory in suppressing the occurrence of blurring after printing, and are not satisfactory particularly in terms of suppressing the occurrence of bleeding in a high humidity environment.
The present invention has been made in view of the above, and an object of the present invention is to provide a method for manufacturing an ink jet recording medium in which occurrence of bleeding with time in a high humidity environment is suppressed.

<1> A first liquid containing inorganic fine particles, a water-soluble resin, and a crosslinking agent is applied onto a support, and (1) at the same time as the application, or (2) during the drying of the application layer formed by the application. The amino acid-containing basic organic compound is contained in any of the coating layers before the coating layer exhibits reduced-rate drying, and 40 to 90% by mass of the amino group-containing basic organic compound has a molecular weight of 700 or less. A method for producing an ink jet recording medium, comprising applying a liquid to form an ink receiving layer.
<2> The method for producing an inkjet recording medium according to <1>, wherein a content ratio of a compound having a molecular weight of 700 or less among the amino group-containing basic organic compound is 50 to 80% by mass.
<3> The method for producing an inkjet recording medium according to <1> or <2>, wherein the molecular weight is 100 to 250.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the inkjet recording medium by which generation | occurrence | production of the bleeding with time in the high humidity environment of the recorded image was suppressed can be provided.

Hereinafter, the present invention will be described in detail.
≪Inkjet recording medium manufacturing method≫
In the method for producing an inkjet recording medium of the present invention, a first liquid containing inorganic fine particles, a water-soluble resin, and a crosslinking agent is applied onto a support, and (1) formed simultaneously with the application or (2) formed by the application. In the course of drying of the applied layer, before the coating layer exhibits reduced-rate drying, it contains an amino group-containing basic organic compound, and 40 to 90% by mass of the amino group-containing basic organic compound is An ink receiving layer is formed by applying a second liquid having a molecular weight of 700 or less.
The ink jet recording medium manufacturing method of the present invention is capable of manufacturing an ink jet recording medium in which the occurrence of bleeding over time in a high humidity environment is suppressed.

In the present invention, the second liquid contains an amino group-containing basic organic compound, and particularly 40 to 90% by mass of an amino group-containing basic organic compound having a molecular weight of 700 or less in the amino group-containing basic organic compound. It is necessary to contain it, and it is further preferable that it is 50-80 mass% from a viewpoint of suppressing generation | occurrence | production of a aging in a high-humidity environment.
When the content ratio is less than 40% by mass, the bleeding with time deteriorates and the ink absorption rate also deteriorates. Moreover, when the said content ratio exceeds 90 mass%, bleeding with time and bronzing will deteriorate.

[Ink receiving layer]
In the ink receiving layer formed by the method for producing an ink jet recording medium of the present invention, a first liquid containing inorganic fine particles, a water-soluble resin, and a crosslinking agent is applied onto a support (application step), and (1) the application Or (2) including an amino group-containing basic organic compound in the course of drying of the coating layer formed by the coating and before the coating layer exhibits reduced-rate drying, 40 to 90% by mass of the basic organic compound is formed by applying a second liquid having a molecular weight of 700 or less.
Hereinafter, the components in the first liquid and the second liquid in the present invention will be described.

(Amino group-containing basic organic compound)
The ink receiving layer in the invention contains at least an amino group-containing basic organic compound containing 40 to 90% by mass of an amino group-containing basic organic compound having a molecular weight of 700 or less (hereinafter also referred to as a specific low molecular compound).
That is, the ink receiving layer in the present invention contains at least two kinds of amino group-containing basic organic compounds, at least one kind is the specific low molecular weight compound, and at least one other kind contains an amino group having a molecular weight exceeding 700. It is a basic organic compound (hereinafter also referred to as a specific polymer compound).

The specific low molecular weight compound in the present invention can be used without limitation as long as it is a basic organic compound having an amino group in the molecule and having a molecular weight of 700 or less.
Among the amino group-containing basic organic compounds, the specific low molecular weight compounds include primary to tertiary monoamines (for example, aliphatic amines such as triethylamine, tripropylamine, tributylamine, trihexylamine, dibutylamine, and butylamine). An aromatic amine such as diethylaniline, dibutylaniline, ethylaniline, aniline, 2-aminopyridine, 3-aminopyridine, 4-aminopyridine, 4- (2-hydroxyethyl) -aminopyridine), diamine (ethylenediamine, Xylenediamine, hexamethylenediamine, trimethylhexamethylenediamine, 1,3-bisaminomethylcyclohexane, metaphenylenediamine, metaxylenediamine), triamine (diethylenetriamine, 1,3,5-triazine-2) 4,6-triamine (melamine)), even more often with an amino group (triethylenetetramine, tetraethylenepentamine), and the like.
Among the above, the specific low molecular weight compound is preferably a compound having a molecular weight of 50 to 500, and more preferably a compound having a molecular weight of 100 to 250, from the viewpoint of suppressing bleeding over time and imparting bending resistance.

As the amino group-containing basic organic compound in the present invention, as the amino group-containing basic organic compound having a molecular weight exceeding 700, those other than the specific low molecular compound can be used without any particular limitation.
Examples of the specific polymer compound include polyether diamine, polyalkylene polyamine, polyvinyl amine, polyamidine, polyallylamine, and derivatives thereof.
Among these, polyallylamine is preferable from the viewpoint of suppressing the occurrence of aging blur.

  The amino group-containing basic organic compound in the present invention is preferably added in a proportion of 0.1 to 7.5% by mass, based on the total solid mass of the ink receiving layer, and is preferably 0.5 to 6.5% by mass. Is more preferable.

(Inorganic fine particles)
The ink receiving layer in the invention contains at least one inorganic fine particle.
The inorganic fine particles form a porous structure when the ink receiving layer is formed, and have a role of improving the ink absorption performance.
In particular, when the solid content of the inorganic fine particles in the ink receiving layer is 40% by mass or more, more preferably more than 50% by mass, with respect to the total solid content of the ink receiving layer, an even better porous structure is obtained. This is preferable because an ink jet recording medium having sufficient ink absorbability can be obtained.
Here, the solid content of fine particles in the ink receiving layer is a content calculated based on components other than water in the composition constituting the ink receiving layer.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

(Water-soluble polyvalent metal salt)
The ink receiving layer in the invention preferably contains at least one water-soluble polyvalent metal compound as a mordant.

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

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

The basic polyaluminum hydroxide compound has a main component represented by the following general formula 1, 2 or 3, for example, [Al ₆ (OH) ₁₅ ] ³⁺ , [Al ₁₈ (OH) ₂₀ ] ⁴⁺ , [Al ₁₃ (OH) ₃₄ ] 5 ⁺ , [Al ₂₁ (OH) ₆₀ ] ^{3 +} , and the like.

[Al ₂ (OH) _n Cl _(6-n) ] _m ·· Formula 1
[Al (OH) ₃ ] _n AlCl ₃ .. Formula 2
Al _n (OH) _m Cl _(3n-m) 0 <m <3n Formula 3

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

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

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

(Nitrogen-containing organic cationic polymer)
The ink receiving layer in the invention preferably contains at least one nitrogen-containing organic cation polymer from the viewpoint of suppressing bleeding of recorded images and dispersibility of inorganic fine particles.
The nitrogen-containing organic cationic polymer in the present invention is not particularly limited, but a polymer having a primary to tertiary amino group or a quaternary ammonium base is preferable.
Examples of the nitrogen-containing organic cation polymer include a homopolymer of a primary to tertiary amino group and a salt thereof, or a monomer (a nitrogen-containing organic cation monomer) having a quaternary ammonium base, or the nitrogen-containing organic What is obtained as a copolymer or condensation polymer of a cationic monomer and another monomer is preferable. These nitrogen-containing organic cationic polymers can be used in any form of water-soluble polymer or water-dispersible latex particles.

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

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

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

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

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

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

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

Among the nitrogen-containing organic cationic polymers described above, from the viewpoint of suppressing bleeding, a cationic polyurethane and a cationic polymer described in JP-A No. 2004-167784 are preferable, and a cationic polyurethane is more preferable.
Examples of commercial products of cationic polyurethane include “Superflex 650”, “F-8564D”, “F-8570D” manufactured by Daiichi Kogyo Seiyaku Co., Ltd., “Neofix IJ” manufactured by Nikka Chemical Co., Ltd. -150 "and the like.
From the viewpoint of silica dispersion, polydiallyldimethylammonium chloride and polymethacryloyloxyethyl-β-hydroxyethyldimethylammonium chloride derivatives are preferable, and polydiallyldimethylammonium chloride is more preferable. Examples of these commercially available products include “Chemistat 7005” manufactured by Sanyo Kasei Co., Ltd.

In the present invention, the content of the nitrogen-containing organic cationic polymer in the ink receiving layer is preferably 1 to 15% by mass with respect to the total solid content of the entire ink receiving layer from the viewpoint of more effectively obtaining the effects of the present invention. 1.5 to 12% by mass is more preferable, and 2 to 10% by mass is particularly preferable.
In the present invention, the total solid content of the ink receiving layer refers to all components excluding water from the composition constituting the ink receiving layer.

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

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

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

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

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

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

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

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

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

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

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

The basis weight of the base paper is preferably 30 to 250 g, and particularly preferably 50 to 200 g. The thickness of the base paper is preferably 40 to 250 μm. The base paper can be given a high smoothness by calendering at the paper making stage or after paper making. The density of the base paper is generally 0.7 to 1.2 g / cm ³ (JIS P-8118).
Furthermore, the base paper stiffness is preferably 20 to 200 g under the conditions specified in JIS P-8143.

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

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

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

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

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

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

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

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

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

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

[Method for producing inkjet recording medium]
In the method for producing an ink jet recording medium of the present invention, a first liquid containing inorganic fine particles, a water-soluble resin, and a crosslinking agent is applied onto a support (hereinafter sometimes referred to as “coating layer forming step”). 1) at the same time as the coating, or (2) in the course of drying of the coating layer formed by the coating, and before the coating layer exhibits reduced-rate drying, containing an amino group-containing basic organic compound, 40 to 90% by mass of the amino group-containing basic organic compound is characterized in that the second liquid having a molecular weight of 700 or less is applied to form an ink receiving layer.

(Coating layer forming process)
The method for producing an inkjet recording medium of the present invention includes a step of forming a coating layer on a support by applying a first liquid containing inorganic fine particles, a water-soluble resin, and a crosslinking agent on the support.
In the coating layer forming step, it is necessary to apply the coating solution on the support, but other coating solutions other than the coating solution may be applied as necessary. A barrier layer solution (intermediate layer solution) may be interposed between the coating solutions.

The form for applying the coating solution is not particularly limited. When two or more coating liquids are coated on the support, each liquid may be simultaneously coated by a known method to form a coating layer, or each liquid may be coated one by one by a known method ( The coating layer may be formed by sequential coating.
The simultaneous multilayer coating can be performed using a known coating apparatus such as an extrusion die coater or a curtain flow coater.
The sequential coating can be performed using a known coating apparatus such as an extrusion die coater, an air doctor coater, a bread coater, a rod coater, a knife coater, a squeeze coater, a reverse roll coater, or a bar coater.

In the coating layer forming step, the wet coating amount of the first solution is preferably ^{100~400g / m 2, 150~300g / m} 2 is more preferable. Moreover, as a solid content application quantity of the said 1st liquid, 10-50 g / m < ² > is preferable and 20-36 g / m < ² > is more preferable.

(First liquid)
The coating liquid in the present invention contains at least one kind of inorganic fine particles, a water-soluble resin, and a crosslinking agent, and further includes a water-soluble polyvalent metal salt, a nitrogen-containing organic cationic polymer (mordant), a dispersant, a surfactant, etc. Other components may be contained.
Further, in the application of the coating solution, it is also preferable to apply the coating solution after in-line mixing a solution containing the water-soluble polyvalent metal salt (preferably basic polyaluminum chloride).
Details of each component such as inorganic fine particles, water-soluble resin, cross-linking agent, water-soluble polyvalent metal salt, nitrogen-containing organic cationic polymer (mordant) are as described in the section of [Ink Receptive Layer], The preferable form is also the same.

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

-Preparation method of coating solution-
In the present invention, a coating solution containing at least inorganic fine particles, a water-soluble resin, and a crosslinking agent can be prepared, for example, as follows.
That is, the vapor phase method silica fine particles and a dispersant are added to water (for example, silica fine particles in water is 10 to 20% by mass), and a high-speed rotating wet colloid mill (for example, “Claire manufactured by M Technique Co., Ltd.) is used. For example, 10000 rpm (preferably 5000-20000 rpm) under high speed rotation conditions, for example, for 20 minutes (preferably 10-30 minutes), followed by crosslinking agent (for example, boric acid), polyvinyl alcohol (PVA) Aqueous solution (for example, PVA having a mass of about 1/3 of the vapor phase silica) and a nitrogen-containing organic cationic polymer are added, and the water-soluble polyvalent metal salt (for example, acetic acid) Zirconyl, basic polyaluminum hydroxide, etc.) can be added and dispersed under the same rotational conditions as described above.
The water-soluble polyvalent metal salt may be added by in-line mixing immediately before application.
Moreover, a liquid-liquid collision type disperser (for example, an optimizer manufactured by Sugino Machine Co., Ltd.) can also be used for the dispersion.
The obtained coating liquid is in a uniform sol state, and a porous ink-receiving layer having a three-dimensional network structure can be formed by applying the coating liquid onto a support by the following coating method and drying it.

In addition, the preparation of the aqueous dispersion composed of the above-mentioned vapor phase method silica and a dispersant may be carried out by preparing a vapor phase method silica aqueous dispersion in advance and adding the aqueous dispersion to the aqueous dispersant solution. The aqueous solution may be added to the vapor phase silica aqueous dispersion, or may be mixed simultaneously. Further, instead of vapor phase silica aqueous dispersion, powder vapor phase silica may be used and added to the aqueous dispersant as described above.
After mixing said vapor phase silica and a dispersing agent, the mixed liquid is refined using a disperser, whereby an aqueous dispersion having an average particle diameter of 50 to 300 nm can be obtained. Dispersers used for obtaining the aqueous dispersion include various types of conventionally known high-speed rotating dispersers, medium stirring dispersers (ball mill, sand mill, etc.), ultrasonic dispersers, colloid mill dispersers, high pressure dispersers and the like. Although a disperser can be used, a stirrer-type disperser, a colloid mill disperser, or a high-pressure disperser is preferable from the viewpoint that the formed fine particles are efficiently dispersed.

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

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

In the method for producing an inkjet recording medium of the present invention, the coating layer formed in the coating layer forming step includes:
(1) At least simultaneously with the application of the first liquid,
(2) At least during the drying of the coating layer formed by applying the first liquid and before the coating layer exhibits reduced-rate drying,
In any of the cases, the amino group-containing basic organic compound is included, and 40 to 90% by mass of the amino group-containing basic organic compound has a step of applying a second liquid having a molecular weight of 700 or less.

As a method of applying the second liquid at the same time as “(1) applying at least the coating liquid (first liquid)”, the first liquid and the second liquid are arranged in this order from the support side. A mode of simultaneous application (multilayer application) is preferable.
The simultaneous coating (multilayer coating) can be performed using a known coating apparatus such as an extrusion die coater or a curtain flow coater.

The method of applying the second liquid before “(2) at least during the drying of the coating layer formed by applying the coating liquid (first liquid) and before the coating layer exhibits reduced-rate drying”, This is a method called “Wet-On-Wet method” or “WOW method”. Details of the “Wet-On-Wet method” are described in paragraph numbers 0016 to 0037 of JP-A-2005-14593, for example.
In the present invention, after forming the coating layer by applying the coating solution (first solution), before the coating layer is in the course of drying and the coating layer exhibits reduced rate drying, (i) Examples include a method of further applying the second liquid onto the coating layer, (ii) a method of spraying by spraying or the like, and (iii) a method of immersing the support on which the coating layer is formed in the second liquid.

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

  In the curing step, “before the coating layer comes to show reduced-rate drying” usually refers to a process for several minutes immediately after the application of the first liquid, and during this time, the solvent in the coated coating layer ( The phenomenon of “constant rate drying” in which the content of the dispersion medium) 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 a condition for the above-mentioned “drying until the coating layer exhibits reduced rate drying”, it is generally carried out at 40 to 180 ° C. for 0.5 to 10 minutes (preferably 0.5 to 5 minutes). The drying time naturally varies depending on the coating amount, but usually the above range is appropriate.

As the wet coating amount of the second solution is preferably ^{5~30g / m 2, 7~25g / m} 2 is more preferable. Moreover, as a solid content application quantity of the said 2nd liquid, 0.2-5 g / m < ² > is preferable and 0.5-3 g / m < ² > is more preferable.

(Second liquid)
The second liquid in the present invention contains at least two amino group-containing basic organic compounds, and the amino group-containing basic organic compound is the aforementioned amino group-containing basic organic compound, and preferred examples are also the same. .
The second liquid in the present invention may further contain a crosslinking agent, a surfactant, and other basic compounds.
As the crosslinking agent and the surfactant, those described above can be used, and preferred examples are also the same.

~ Metal compound ~
The second liquid in the present invention may contain a metal compound.
As the metal compound contained in the second liquid, those that are stable under basicity can be used without limitation, and are any of the aforementioned water-soluble polyvalent metal salts, metal complex compounds, inorganic oligomers, or inorganic polymers. Also good. For example, zirconium compounds and compounds listed as inorganic mordants in paragraph numbers 0100 to 0101 in JP-A-2005-14593 are suitable. Examples of the metal complex compound include metal complexes described in “Chemistry Review No. 32 (1981)” edited by the Chemical Society of Japan, “Coordination Chemistry Review”, Vol. 84, pages 85-277. (1988) and JP-A-2-182701, transition metal complexes containing a transition metal such as ruthenium can be used.

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

  The second liquid may contain other mordant components as necessary.

Moreover, water, an organic solvent, or these mixed solvents can be used for the solvent used for preparation of a 2nd liquid. Examples of the organic solvent that can be used for coating include alcohols such as methanol, ethanol, n-propanol, i-propanol, and methoxypropanol, ketones such as acetone and methyl ethyl ketone, tetrahydrofuran, acetonitrile, ethyl acetate, and toluene. .

(Other processes)
In the present invention, 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, thereby surface smoothness. It is possible to improve glossiness, transparency and coating strength. However, the calendar process may cause a decrease in the porosity (that is, the ink absorptivity may be decreased), so it is necessary to set conditions under which the decrease in the porosity is small.

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

[Inkjet recording method]
There is no particular limitation on the ink jet recording method for recording an image on the ink jet recording medium produced by the method of producing an ink jet recording medium of the present invention, and a known method, for example, an ink using electrostatic attraction is used. Charge control method to discharge, drop-on-demand method (pressure pulse method) using vibration pressure of piezo element, acoustic ink jet method to discharge ink using radiation pressure by irradiating ink by changing electrical signal into acoustic beam In addition, a thermal ink jet method using the pressure generated by heating the ink to form bubbles and the like can be used. The ink jet recording method includes a method of ejecting a large number of low-density inks called photo inks in a small volume, a method of improving image quality using a plurality of inks having substantially the same hue and different concentrations, and colorless and transparent. A method using ink is included.

The present invention will be described more specifically with reference to the following examples. The scope of the present invention is not limited to the specific examples shown below. Unless otherwise specified, “part” and “%” are based on mass.
<Example 1>
≪Preparation of inkjet recording medium≫
[Production of support]
Wood pulp consisting of 100 parts of LBKP is beaten to 300 ml Canadian freeness with a double disc refiner, 0.5 parts of epoxidized behenamide, 1.0 part of anionic polyacrylamide, 0.1 part of polyamide polyamine epichlorohydrin, 0.5 part of cationic polyacrylamide All the parts were added at an absolutely dry mass ratio to the pulp, and weighed with a long net paper machine to make a base paper of 170 g / m ² .

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

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

  Furthermore, after the corona discharge treatment is applied to the felt surface (surface) side where the resin layer is not provided, anatase-type titanium dioxide 10%, a trace amount of ultramarine blue, and a fluorescent whitening agent 0.01% (vs. polyethylene) Low-density polyethylene containing MFR (melt flow rate) 3.8 is melt-extruded to a thickness of 29 μm using a melt extruder, and a high-gloss thermoplastic resin layer is formed on the surface side of the base paper. (Hereinafter, this highly glossy surface is referred to as “front side”) to obtain a resin-coated paper. This was designated as Support 1 used in this example.

[Preparation of coating solution]
(1) Gas phase method silica fine particles, (2) ion-exchanged water, (3) “Charol DC-902P”, (4) “ZA-30”, and (5) boric acid shown in the following composition Were mixed using a liquid-liquid collision type disperser (Ultimizer, manufactured by Sugino Machine Co., Ltd.), and the obtained dispersion was heated to 45 ° C. and held for 20 hours. Thereafter, (6) polyvinyl alcohol solution was added to the dispersion at 30 ° C. to prepare coating solution 1 (ink-receiving layer-forming coating solution).

-Composition of coating solution 1-
(1) Gas phase method silica fine particles (inorganic fine particles) 8.9 parts (AEROSIL300SF75, manufactured by Nippon Aerosil Co., Ltd.)
(2) Ion-exchanged water ... 54.8 parts (3) "Charol DC-902P" (51.5% aqueous solution) ... 0.78 parts (dispersant, nitrogen-containing organic cationic polymer, Daiichi Kogyo Seiyaku) (Made by Co., Ltd.)
(4) “ZA-30”: 0.48 part (Daiichi Rare Element Chemical Co., Ltd., zirconyl acetate)
(5) Boric acid (crosslinking agent) ... 0.5 part (6) Polyvinyl alcohol (water-soluble resin) solution ... 25.9 parts-Composition of the solution-
・ PVA235 (saponification degree 88%, polymerization degree 3500, manufactured by Kuraray Co., Ltd.)
・ ・ ・ 2.3 parts ・ Ion-exchanged water ・ ・ ・ 23.5 parts ・ Diethylene glycol monobutyl ether ・ ・ ・ 0.55 parts (Butisenol 20P, manufactured by Kyowa Hakko Chemical Co., Ltd.)
"Surfinol 420" 0.07 part (ethylene oxide adduct of acetylene glycol compound, surfactant,
(HLB value 4, manufactured by Nissin Chemical Industry Co., Ltd.)
(7) “Superflex 650”: 1.5 parts (Nitrogen-containing organic cationic polymer emulsion, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)

<Formation of ink receiving layer>
Wherein after the corona discharge treatment on the front side of the support 1, to the front surface, after in-line mixing the following line solution to 185 g / m ² of the coating solution 1 at a rate of 16.0 g / m ^2, coating The liquid temperature was set to 38 ° C., and an application layer was formed by applying with an extrusion die coater.

~ Composition of inline liquid ~
(1) Alpha-in 83 (manufactured by Daimei Chemical Co., Ltd.) 2.0 parts (2) Ion exchange water 7.8 parts (3) Himax SC-507 0.2 parts ( Dimethylamine / epichlorohydrin polycondensate, manufactured by Hymo Corporation)

The coating layer formed as described above was dried with a hot air dryer at 80 ° C. (wind speed of 3 to 8 m / sec) until the solid content concentration of the coating layer became 24%. This coating layer exhibited a constant rate of drying during this period. Immediately after that, it is immersed in a liquid (second liquid) containing a basic compound having the following composition for 3 seconds to deposit 15 g / m ² on the coating layer, and further dried at 72 ° C. for 10 minutes (drying step). An ink receiving layer was formed on the support.

-Composition of the liquid containing the basic compound (second liquid)-
(1) Boric acid: 0.65 parts (2) Polyallylamine “PAA-03” (20% aqueous solution): 10.0 parts (weight average molecular weight 3000, manufactured by Nittobo Co., Ltd.)
(3) Ion-exchanged water ... 72.0 parts (4) Tetraethylenepentamine (molecular weight 189) ... 1.5 parts (5) Polyoxyethylene lauryl ether (surfactant) 9.0 parts ("Emulgen 109P" manufactured by Kao Corporation (10% aqueous solution), HLB value 13.6)

  As described above, the ink jet recording medium 1 of the present invention in which the ink receiving layer having a dry film thickness of 37 μm was provided on the support was obtained.

[Example 2]
Example 1 is different from Example 1 except that 1.5 parts of ethylenediamine (molecular weight 60) is used instead of 1.5 parts of tetraethylenepentamine used for the preparation of the liquid containing the basic compound (second liquid). In the same manner, an ink jet recording medium was produced.

[Example 3]
In Example 1, the amount of polyallylamine used for the preparation of the liquid containing the basic compound (second liquid) was changed to 10.0 parts instead of 10.0 parts, and the amount of tetraethylenepentamine added was 1 An ink jet recording medium was prepared in the same manner as in Example 1 except that the content was changed to 2.1 parts instead of .5 parts.

[Example 4]
An ink jet recording medium was produced in the same manner as in Example 2 except that ethylenediamine was used instead of tetraethylenepentamine used in the preparation of the liquid containing the basic compound (second liquid).

[Example 5]
An ink jet recording medium was prepared in the same manner as in Example 2, except that diethylenetriamine was used instead of tetraethylenepentamine used in the preparation of the liquid containing the basic compound (second liquid).

[Example 6]
An ink jet recording medium was produced in the same manner as in Example 2 except that pentaethylenehexamine was used instead of tetraethylenepentamine used in the preparation of the liquid containing the basic compound (second liquid).

[Example 7]
In Example 1, the amount of polyallylamine used in the preparation of the liquid containing the basic compound (second liquid) was changed to 10.0 parts instead of 10.0 parts, and the amount of tetraethylenepentamine added was 1 An inkjet recording medium was produced in the same manner as in Example 1 except that 4.2 parts was used instead of 0.5 parts.

[Comparative Example 1]
In Example 1, the amount of polyallylamine used in the preparation of the liquid containing the basic compound (second liquid) was changed to 10.0 parts instead of 10.0 parts, and the amount of tetraethylenepentamine added was 1 An ink jet recording medium was produced in the same manner as in Example 1 except that 1.0 part was used instead of 0.5 part.

[Comparative Example 2]
In Example 1, the polyallylamine used for the preparation of the liquid containing the basic compound (second liquid) was not used, and the addition amount of tetraethylenepentamine was changed to 3.5 parts instead of 1.5 parts. Prepared an ink jet recording medium in the same manner as in Example 1.

[Comparative Example 3]
Example 2 except that 1.5 parts of a 10% aqueous solution of NaOH was used instead of 1.5 parts of tetraethylenepentamine used in the preparation of the liquid containing the basic compound (second liquid) in Example 1. In the same manner, an ink jet recording medium was produced.

≪Evaluation≫
<Measurement of bleeding over time>
Using an inkjet printer “PM970C” manufactured by Epson Corporation, a grid-like linear pattern (line width 0.28 mm) was printed on each inkjet recording medium adjacent to the magenta and black inks at 25 ° C., After storage for 10 days in a constant temperature and humidity chamber of 90% RH, bleeding (bleeding with time) was evaluated according to the following criteria.
~Judgment criteria~
A: No bleeding was observed.
○: Although bleeding was observed, there was no problem in practical use.
X: Bleeding was observed and there was a problem in practical use.
XX: Significant bleeding was observed and there was a problem in practical use.

<Measurement of bronzing>
After being allowed to stand for 24 hours under environmental conditions of 25 ° C. and 70% RH, a solid image was recorded using an ink jet printer (trade name: MP-950, manufactured by Canon Inc.) using cyan ink. The obtained cyan image was visually observed, and the presence or absence of metallic luster was evaluated according to the following evaluation criteria.
<Evaluation criteria>
○: No metallic luster was observed, or a slight metallic luster was observed, but there was no problem.
(Triangle | delta): Although the metallic luster was seen, it was a grade which can be accept | permitted practically.
X: A metallic luster was remarkably recognized.

<Measurement of ink absorption speed>
Printing was recorded using an ink jet printer (trade name: MP-950, manufactured by Canon Inc.), and after the recording was completed, the time until the printed part was lightly rubbed with a fingertip to remove dirt was measured, and the following evaluations were made. Evaluation was made according to criteria.
<Evaluation criteria>
A: The ink absorption speed was less than 3 seconds.
Δ: The ink absorption speed was 3 seconds or more and less than 7 seconds.
X: The ink absorption speed was 7 seconds or more.

<Measurement of bending resistance>
Under an environmental condition of a temperature of 10 ° C. and a humidity of 20% RH, an ink jet recording sheet is wound around each of metal rods having different diameters so that the ink receiving layer faces outward, and cracks are generated in the ink receiving layer. The maximum diameter was determined, and this was used as an index to evaluate bending resistance according to the following evaluation criteria. The occurrence of cracks was visually observed using a 10 × magnifier.
<Evaluation criteria>
○: Diameter less than 20 mm Δ: Diameter 20 mm or more, less than 40 mm ×: Diameter 40 mm or more

  As is clear from Table 1 above, all of the examples having the configuration of the present invention have good evaluation items, and in particular, the improvement of aging blur in Examples 2, 4 and 5 was good.

Claims (3)

A first liquid containing inorganic fine particles, a water-soluble resin and a crosslinking agent is applied onto a support, and (1) at the same time as the application, or (2) during the drying of the application layer formed by the application, Before the coating layer shows reduced-rate drying, it contains an amino group-containing basic organic compound, and 40 to 90% by mass of the amino group-containing basic organic compound gives a second liquid having a molecular weight of 700 or less. And forming an ink receiving layer. An ink jet recording medium manufacturing method, comprising:   2. The method for producing an ink jet recording medium according to claim 1, wherein a content ratio of a compound having a molecular weight of 700 or less in the amino group-containing basic organic compound is 50 to 80 mass%.   The method for producing an inkjet recording medium according to claim 1 or 2, wherein the molecular weight is 100 to 250.