JP2007185885A - Inkjet recording medium and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an inkjet recording medium capable of preventing defects on the surface of an ink receiving layer from being generated, and the inkjet recording medium which is obtained by the method and is excellent in ozone resistance. <P>SOLUTION: The method for manufacturing the inkjet recording medium at least comprises a process wherein a coating liquid is obtained by mixing in in-line an ink receiving layer forming the liquid comprising an inorganic fine particle and a water-soluble binder, and a mordant mixing solution comprising a cationic polymer or a basic aluminum poly-hydroxide compound, and a surfactant, and a process wherein a coating layer is formed by coating a substrate with the coating liquid. The inkjet recording medium is manufactured by this method. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink jet recording medium which is a recording medium suitably used for the ink jet recording method and a method for manufacturing the same.

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

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

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

For example, gazettes (see Patent Documents 1 and 2) propose an ink jet recording medium in which a recording layer containing fine inorganic pigment particles and a water-soluble binder and having a high porosity is provided on a support. .
These recording sheets, in particular, ink jet recording media provided with a recording layer having a porous structure using silica as inorganic fine particles are excellent in ink absorbability due to the structure, and have a high ink receiving capacity capable of forming a high-resolution image. It has performance and can exhibit high gloss.

However, since these are porous coatings, they have high gas permeability and may promote deterioration of the components contained in the recording layer.
Trace gases in the air, especially ozone, cause discoloration of recorded images over time. Since the recording material composed of the recording layer having the porous structure described above has a large number of voids, the recorded image is easily faded by ozone gas in the air. For this reason, resistance to ozone in the air (ozone resistance) is a very important characteristic for the recording material having the recording layer having the porous structure.
JP 10-119423 A Japanese Patent Laid-Open No. 10-217601

Various additives have been studied in order to improve properties such as ozone resistance. However, when an additive is added to the ink receiving layer, defects such as cracks may occur on the surface of the ink receiving layer.
The present invention has been made in view of the above problems, and provides a method for producing an ink jet recording medium capable of preventing the occurrence of defects on the surface of the ink receiving layer and an ink jet recording medium excellent in ozone resistance obtained by the method. The purpose is to provide.

That is, the present invention
<1> A step of obtaining a coating liquid by in-line mixing an ink receiving layer forming liquid containing inorganic fine particles and a water-soluble binder and a mordant mixed solution containing a cationic polymer or a water-soluble aluminum compound and a surfactant. And a step of applying the coating liquid onto a support to form a coating layer.

  <2> The method for producing an ink jet recording medium according to <1>, wherein at least one of the ink receiving layer forming liquid and the mordant mixed solution further contains a crosslinking agent.

  <3> The method for producing an ink jet recording medium according to <2>, wherein the crosslinking agent is boric acid.

  <4> The method for producing an ink jet recording medium according to any one of <1> to <3>, wherein the water-soluble binder is a polyvinyl alcohol resin.

  <5> At the same time as (1) when the coating liquid is applied to the coating layer, and (2) during the drying of the coating layer and before the coating layer exhibits reduced-rate drying, <1> to << 1>, further comprising a step of applying a basic solution containing a functional compound to cross-link and cure the coating layer, and forming the ink receiving layer formed by cross-linking and curing the coating layer on the support. 4> The method for producing an inkjet recording medium according to any one of the above.

  <6> An inkjet recording medium produced by the method for producing an inkjet recording medium according to any one of <1> to <5>.

  ADVANTAGE OF THE INVENTION According to this invention, the inkjet recording medium excellent in ozone resistance obtained by the manufacturing method of the inkjet recording medium which can prevent generation | occurrence | production of the defect of the ink receiving layer surface, and its method can be provided.

Hereinafter, the ink jet recording medium of the present invention and the manufacturing method thereof will be described in detail.
The method for producing an ink jet recording medium of the present invention comprises an ink receiving layer forming liquid containing inorganic fine particles and a water-soluble binder, and a mordant mixed solution containing a cationic polymer or a water-soluble aluminum compound and a surfactant in-line. At least a step of mixing to obtain a coating solution and a step of coating the coating solution on a support to form a coating layer.

  Coating layer using a coating solution obtained by in-line mixing a mordant mixed solution containing a cationic polymer or a water-soluble aluminum compound and a surfactant with an ink-receiving layer forming solution containing inorganic fine particles and a water-soluble binder By forming, it is possible to prevent the occurrence of defects such as cracks in the surface of the ink receiving layer obtained after drying of the coating layer. This is presumably because the inclusion of the surfactant improved the miscibility of the cationic polymer or water-soluble aluminum compound with the first coating solution.

  In the case of preparing the coating liquid, a known in-line mixer is preferably used when mixing the two liquids. A preferable in-line mixer in the present invention is described in JP-A No. 2002-85948.

  The ink jet recording medium of the present invention is produced by the method for producing an ink jet recording medium of the present invention. Since the ink receiving layer according to the ink jet recording medium of the present invention contains a cationic polymer or a water-soluble aluminum compound, the ink jet recording medium of the present invention is excellent in ozone resistance.

Hereinafter, materials used in the method for producing an inkjet recording medium of the present invention will be described.
[Inorganic fine particles]
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, water. Examples thereof include zinc oxide, alumina, aluminum silicate, calcium silicate, magnesium silicate, zirconium oxide, zirconium hydroxide, cerium oxide, lanthanum oxide, and yttrium oxide. Among these, silica fine particles, colloidal silica, alumina fine particles, or pseudoboehmite is 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 20 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 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 “gas phase method silica” means anhydrous silica fine particles obtained 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 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 large 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 as small as ² to 3 / nm ² , so that it is sparse soft agglomeration (flocculate), resulting in a structure with 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, if the dispersion is performed to an appropriate particle size, transparency is imparted to the ink receiving layer. And high color density and good color developability can be obtained. The transparency of the ink-receiving layer is not only for applications that require transparency, such as OHP, but also for high color density and good color development gloss even when applied to recording sheets such as photo glossy paper. Is important.

  The average primary particle size of the inorganic fine particles (for example, vapor-phase process silica) is preferably 50 nm or less, more preferably 3 to 50 nm, from the viewpoint of the quick drying property (ink absorption rate). 30 nm is more preferable, 3 to 20 nm is particularly preferable, and 3 to 10 nm is most preferable. Since the vapor phase silica is easily adhered to each other by hydrogen bonding with a silanol group, when the average primary particle diameter is 50 nm or less, a structure having a large porosity can be formed, and ink absorption characteristics can be effectively obtained. It is preferable because it can be improved.

  Gas phase method silica may be used in combination with the other inorganic 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 used 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 cc / g, more preferably 0.5 to 1.5 cc / 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 binder]
Examples of the water-soluble binder used in the ink-receiving layer include polyvinyl alcohol resins that are resins having a hydroxy group as a hydrophilic structural unit [polyvinyl alcohol (PVA), acetoacetyl-modified polyvinyl alcohol, cation-modified polyvinyl alcohol, anion-modified polyvinyl. Alcohol, silanol-modified polyvinyl alcohol, polyvinyl acetal, etc.], cellulosic resins [methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC), hydroxypropyl cellulose (HPC), hydroxyethyl methyl cellulose, hydroxy Propylmethylcellulose, etc.), chitins, chitosans, starch, resins having ether linkages Side (PEO), polypropylene oxide (PPO), polyethylene glycol (PEG), polyvinyl ether (PVE), etc.], resins having a carbamoyl group [polyacrylamide (PAAM), polyvinylpyrrolidone (PVP), polyacrylic acid hydrazide, etc.), etc. Is mentioned.
Moreover, the polyacrylic acid salt which has a carboxyl group as a dissociable group, maleic acid resin, alginate, gelatins, etc. can be mentioned.

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.
Examples of water-soluble binders other than polyvinyl alcohol-based resins include compounds described in “0011” to “0014” of JP-A No. 11-165461.
These water-soluble binders may be used alone or in combination of two or more.

  As content of the water-soluble binder in this invention, 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.

In the present invention, the inorganic fine particles mainly constituting the ink receiving layer and the water-soluble binder described above 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 binder combined with inorganic fine particles, particularly silica fine particles, is important. When the gas phase method silica is used, the water-soluble binder 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.

  Moreover, you may use together polyvinyl alcohol-type resin and the said other water-soluble binder. When the other water-soluble binder and the polyvinyl alcohol resin are used in combination, the content of the polyvinyl alcohol resin in the total water-soluble binder is preferably 50% by mass or more, and more preferably 70% by mass or more.

<Content ratio of inorganic fine particles and water-soluble binder>
The mass content ratio [PB ratio (x / y)] between the inorganic fine particles (x) and the water-soluble binder (y) greatly affects the film structure and film strength of the ink receiving layer. That is, as the mass content ratio [PB ratio] increases, the porosity, pore volume, and surface area (per unit mass) increase, but the density and strength tend to decrease.

  The ink receiving layer of the present invention prevents the decrease in film strength and cracking during drying caused by the PB ratio being too large as the mass content ratio [PB ratio (x / y)], and When the PB ratio is too small, the gap is easily blocked by the resin, and from the viewpoint of preventing the ink absorbency from being lowered due to the decrease in the porosity, 1.5 to 10 is preferable.

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

For example, a coating solution in which a vapor phase method silica fine particle having an average primary particle size of 20 nm or less and a water-soluble binder are completely dispersed in an aqueous solution at a mass ratio (x / y) of 2 to 5 is applied on a support. When the coating layer is dried, a three-dimensional network structure is formed in which the secondary particles of silica fine particles are network chains, the average pore diameter is 30 nm or less, the porosity is 50 to 80%, and the pore specific volume is 0.00. A translucent porous film having a specific surface area of 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-jet recording medium of the present invention preferably contains a water-soluble binder in the ink-receiving layer, and the ink-receiving layer further comprises a coating layer containing a cationic polymer, inorganic fine particles and a water-soluble binder. A preferred embodiment is a porous layer containing a crosslinking agent capable of crosslinking the binder and cured by a crosslinking reaction between the crosslinking agent and the water-soluble binder. At least one of the ink receiving layer forming liquid and the mordant mixed solution in the present invention may contain a crosslinking agent.

Boron compounds are preferred for crosslinking the water-soluble binder, particularly polyvinyl alcohol resins. Examples of the boron compound, borax, boric acid, borates (eg, _{orthoborate, InBO 3, ScBO 3, YBO} 3, LaBO 3, Mg 3 (BO 3) 2, Co 3 (BO 3) ₂ , diborate (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 ), tetraboric acid Salt (eg, Na ₂ B ₄ O ₇ · 10H ₂ O), pentaborate (eg, KB ₅ O ₈ · 4H ₂ O, Ca ₂ B ₆ O ₁₁ · 7H ₂ O, CsB ₅ O ₅ ), etc. Among them, 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 binder, the following compounds other than the boron compound can also 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 above crosslinking agents may be used singly or in combination of two or more.

As will be described later, in the crosslinking and curing, a coating liquid containing inorganic fine particles, a water-soluble binder and the like (hereinafter, a coating liquid obtained by in-line mixing an ink receiving layer forming liquid and a mordant mixed liquid is referred to as a “first liquid”. And / or a crosslinking agent is added to the following basic solution, and (1) the coating solution is applied to form a coating layer, and (2) the coating solution is applied. When the coating layer is in the middle of drying and before the coating layer exhibits reduced-rate drying, a basic solution having a pH of 7.1 or higher (hereinafter sometimes referred to as “second liquid”) is applied to the coating layer. It is preferable to carry out by giving to. 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 binder containing fine particles and polyvinyl alcohol, crosslinking curing is performed by (1) the coating described above. Simultaneously with application of the liquid, (2) at any time during the dry coating of the coating layer formed by coating the coating liquid and before the coating layer exhibits reduced drying, the pH is 7.1 or more It is performed by applying a basic solution (second liquid) to the coating layer. The boron compound as a cross-linking 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 a water-soluble binder, and, as for the usage-amount of a crosslinking agent, 5-40 mass% is more preferable.

[Water-soluble aluminum compound]
The mordant mixed solution according to the present invention contains a cationic polymer or a water-soluble aluminum compound.
In the present invention, “water-soluble” refers to a compound that does not form a precipitate when it is made into a 10% aqueous solution.
As the water-soluble aluminum compound according to the present invention, for example, inorganic salts include aluminum chloride or a hydrate thereof, aluminum sulfate or a hydrate thereof, ammonium alum and the like. Specifically, for example, aluminum sulfate, aluminum sulfite, aluminum thiosulfate, polyaluminum chloride, aluminum nitrate nonahydrate, aluminum chloride hexahydrate, aluminum acetate, aluminum lactate, basic aluminum thioglycolate, aluminum alum Etc. Furthermore, a basic polyaluminum hydroxide compound which is an inorganic aluminum-containing cationic polymer is known and preferably used. Of these, basic polyaluminum hydroxide compounds are preferred.
Here, the basic polyaluminum hydroxide compound has a main component represented by Al ₂ (OH) _n Cl _m (m + n = 6), for example, Al ₂ (OH) ₅ Cl ₁ , Al ₂ (OH). _4.5 A water-soluble polyaluminum hydroxide containing a basic and high-molecular polynuclear condensed ion such as Cl _1.5 , Al ₂ (OH) ₄ Cl ₂ or the like stably.

  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.

The ink receiving layer in the invention may contain other water-soluble polyvalent metal compounds other than the water-soluble aluminum compounds described above.
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, iron, zinc, zirconium, chromium, magnesium, tungsten, and molybdenum can be given.
Specifically, for example, calcium acetate, calcium chloride, calcium formate, calcium sulfate, calcium butyrate, barium acetate, barium sulfate, barium phosphate, barium oxalate, naphthoresorcin carboxylate, barium butyrate, manganese chloride, manganese acetate, Manganese formate dihydrate, manganese ammonium sulfate hexahydrate, cupric chloride, ammonium copper (II) chloride dihydrate, copper sulfate, copper (II) butyrate, copper oxalate, copper phthalate, copper citrate , Copper gluconate, Naphthene copper, Cobalt chloride, Cobalt thiocyanate, Cobalt sulfate, Cobalt acetate (II), Cobalt naphthenate, Nickel sulfate hexahydrate, Nickel chloride hexahydrate, Nickel acetate tetrahydrate, Sulfuric acid Nickel ammonium hexahydrate, nickel amidosulfate tetrahydrate, nitric acid sulfamate , Nickel 2-ethylhexanoate, ferrous bromide, ferrous chloride, ferric chloride, ferrous sulfate, ferric sulfate, iron (III) citrate, iron (III) lactate trihydrate , Triammonium iron (III) trioxalate trihydrate, zinc bromide, zinc chloride, zinc nitrate hexahydrate, zinc sulfate, zinc acetate, zinc lactate, zirconium acetate, zirconium tetrachloride, zirconium chloride, chloride Zirconium oxide octahydrate, hydroxy zirconium chloride, chromium acetate, chromium sulfate, magnesium acetate, magnesium oxalate, magnesium sulfate, magnesium chloride hexahydrate, magnesium citrate nonahydrate, sodium phosphotungstate, sodium citrate Tungsten, 12 tungstophosphoric acid n hydrate, 12 tungstosilicic acid 26 hydrate, molybdenum chloride, 12 molybdophosphorus n-hydrate, zinc phenolsulfonate, zinc ammonium acetate, ammonium zinc carbonate, and the like. 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, compounds composed of Group 4A metals (for example, zirconium and titanium) of the periodic table are preferable.

  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. Examples of water-soluble compounds containing zirconium include zirconium acetate, zirconium chloride, hydroxy zirconium chloride, zirconium nitrate, basic zirconium carbonate, zirconium hydroxide, zirconium lactate, zirconium carbonate / ammonium, zirconium carbonate / potassium, zirconium sulfate, zirconium fluoride. Compounds and the like.

  The total amount of the water-soluble aluminum compound and the water-soluble polyvalent metal compound used as necessary is preferably 0.1 to 10% by mass with respect to the inorganic fine particles, and 0.5 to 8 The mass% is more preferable.

[Cationic polymer]
The cationic polymer used in the present invention is not particularly limited, but it is preferable to use a cationic polymer having an I / O value of 3 or more. Here, the I / O value is a value obtained by dividing an inorganic group based on an organic conceptual diagram by an organic group. The I / O value can be determined by the method described in “Organic Conceptual Diagram-Basics and Applications” (1984 Yoshio Koda, Sankyo Publishing).

  Here, an organic conceptual diagram is an orthogonal coordinate system in which the properties of a compound are divided into an organic group representing a covalent bond and an inorganic group representing an ionic bond, and all organic compounds are named organic and inorganic axes. The inorganic value based on this is determined based on the hydroxyl group based on the inorganicity, that is, the influence of various substituents on the boiling point. If the distance between the boiling point curve of the straight-chain paraffin and the straight-line paraffin is about 100 ° C., the influence of one hydroxyl group is 100. On the other hand, the organic value is based on the number of carbon atoms that represent the methylene group in units of the number of methylene groups in the molecule. The average value of the boiling point increase due to addition of one carbon in the vicinity of 5 to 10 carbon atoms of the linear compound is 20 ° C., and this is a value determined as 20 on the basis of this. The inorganic value and the organic value are determined so as to correspond one-to-one on the graph. The I / O value is calculated from these values.

  In the present invention, the I / O value of the cationic polymer is more preferably 4 or more. By using a cationic polymer having an I / O value of 3 or more, an effect of improving ozone resistance can be obtained.

Specific examples of the cationic polymer include the cationic polymer described in the section of the mordant described later and polyalkylamine epichlorohydrin polycondensate. From the viewpoint of the effect of improving ozone resistance, polyalkylamine epichlorohydride. A phosphorus polycondensate is preferred.
The content of the ink receiving layer of the cationic polymer is preferably from ^{0.01g / m 2 ~2.0g / m 2} , 0.1g / m 2 ~1.0g / m 2 is more preferable. If the content of the cationic polymer in the ink receiving layer is less than 0.01 g / m ² , the effect of improving ozone resistance is small, and if it is more than 2.0 g / m ² , bronzing may occur.

[mordant]
In the present invention, it is preferable to add a mordant to the ink receiving layer in order to further improve the water resistance and aging resistance of the formed image.
As such a mordant, a cationic polymer (cationic mordant) or an inorganic mordant is preferable as an organic mordant, and the mordant is present in a liquid ink having an anionic dye as a coloring material by being present in the ink receiving layer. Can interact with each other to stabilize the color material and improve water resistance and aging resistance. The organic mordant and the inorganic mordant may be used alone or in combination with the organic mordant and the inorganic mordant.

As the cationic mordant, a polymer mordant having a primary to tertiary amino group or a quaternary ammonium base as a cationic group is generally used. On the other hand, in the present invention, a cationic non-polymer mordant can also be used.
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 (mordant monomer), and the mordant monomer and other monomers (hereinafter, What is obtained as a copolymer or condensation polymer with “non-mordant monomer”). Moreover, these polymer mordants can be used in any form of a water-soluble polymer or water-dispersible latex particles.

  Examples of the monomer (mordanting monomer) include trimethyl-p-vinylbenzylammonium chloride, trimethyl-m-vinylbenzylammonium chloride, triethyl-p-vinylbenzylammonium chloride, triethyl-m-vinylbenzylammonium chloride, N , N-dimethyl-N-ethyl-Np-vinylbenzylammonium chloride, N, N-diethyl-N-methyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-Nn-propyl-N -P-vinylbenzylammonium chloride, N, N-dimethyl-Nn-octyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N-benzyl-Np-vinylbenzylammonium chloride, N, N-die Ru-N-benzyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N- (4-methyl) benzyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N-phenyl-N -P-vinylbenzylammonium chloride;

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

  N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-diethylaminopropyl (meth) acrylate, N, N- Dimethylaminoethyl (meth) acrylamide, N, N-diethylaminoethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N, N-diethylaminopropyl (meth) acrylamide, and salts thereof (for example, hydrochloride) Nitrate, acetate, lactate, methanesulfonate, p-toluenesulfonate, etc.);

  Trimethyl-2- (methacryloyloxy) ethylammonium chloride, triethyl-2- (methacryloyloxy) ethylammonium chloride, trimethyl-2- (acryloyloxy) ethylammonium chloride, triethyl-2- (acryloyloxy) ethylammonium chloride, trimethyl- 3- (methacryloyloxy) propylammonium chloride, triethyl-3- (methacryloyloxy) propylammonium chloride, trimethyl-2- (methacryloylamino) ethylammonium chloride, triethyl-2- (methacryloylamino) ethylammonium chloride, trimethyl-2- (Acryloylamino) ethylammonium chloride, triethyl-2- (acryloylamino) Tylammonium 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, as mordant monomers, N-vinylimidazole, N-vinyl-2-methylimidazole, 2-vinylpyridine, 4-vinylpyridine, 4-vinyl-N-methyl-pyridinium chloride, 4-vinyl-N-ethyl-pyridinium Examples thereof include bromide, dimethyl diallylammonium chloride, monomethyl diallylammonium chloride, and the like.
These mordant monomers can be used singly or in combination of two or more copolymerizable monomers.

The non-mordant monomer does not contain a basic or cationic moiety such as a primary to tertiary amino group and a salt thereof, or a quaternary ammonium base, and does not show an interaction with a dye in an inkjet ink. Or the monomer which interaction is substantially small is said.
Examples of the non-mordant monomer include (meth) acrylic acid alkyl ester [for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, (meth) acrylic acid n -Butyl, isobutyl (meth) acrylate, t-butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth) acrylic acid (Meth) acrylic acid C1-18 alkyl ester such as lauryl, stearyl (meth) acrylate], (meth) acrylic acid cycloalkyl ester [(meth) acrylic acid cyclohexyl etc.], (meth) acrylic acid aryl Esters [phenyl (meth) acrylate, etc.], aralkyl esters [(meth) Benzyl crylate, etc.], substituted (meth) acrylic acid alkyl esters [eg 2-hydroxyethyl (meth) acrylate, methoxymethyl (meth) acrylate, allyl (meth) acrylate, etc.], (meth) acrylamides [For example, (meth) acrylamide, dimethyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, etc.], aromatic vinyl [styrene, vinyl toluene, α-methylstyrene, etc.], vinyl Esters [vinyl acetate, vinyl propionate, vinyl versatate, etc.], allyl esters [eg, allyl acetate], halogen-containing monomers [vinylidene chloride, vinyl chloride, etc.], vinyl cyanide [(meth) acrylonitrile, etc.], Olefin [ethylene, propylene Etc.].
These non-mordant monomers can also be used singly or in combination of two or more.

  Further, as the polymer mordant, polyethyleneimine (and derivatives thereof), polyvinylamine (and derivatives thereof), polyallylamine (and derivatives thereof), polyamidine, cationic polysaccharides (cationized starch, chitosan), dicyan cationic resin ( Examples thereof include dicyandiamide-formalin polycondensate), polyamine cationic resin (dicyandiamide-diethylenetriamine polycondensate), epichlorohydrin-dimethylamine addition polymer, dimethyldiallylammonium chloride-sulfur dioxide copolymer, and the like.

  As the organic mordant in the present invention, a polymer having a quaternary ammonium base is preferable, and a (meth) acrylate polymer, a vinylbenzylammonium polymer having a quaternary ammonium base having a weight average molecular weight of 1,000 to 100,000, or A diallylammonium-based polymer is particularly preferred.

In the present invention, the mordant amount contained in the ink receiving layer is preferably from ^{0.01g / m 2 ~10g / m 2} , 0.1g / m 2 ~5g / m 2 is more preferable.

At least one of the ink receiving layer forming liquid and the mordant mixed solution may further contain a water-dispersible latex. Specific examples of the water-dispersible latex include cation-modified resin latex, anion-modified resin latex, resin latex without charge, etc. Among them, cation-modified resin latex is preferable, and cation-modified urethane latex is more preferable. . In the present invention, water-dispersible latex contained in the ink-receiving layer is preferably ^{0.1g / m 2 ~3.0g / m 2} , 0.1g / m 2 ~1.5g / m 2 is more preferable. Improving effect bleeding so long as the content of 0.1g / m ² ~3.0g / m ² of water-dispersible latex is big, and ozone resistance is improved. When the content is more than 3.0 g / m ² , the ink absorption amount may decrease.

[Surfactant]
The mordant mixed solution according to the present invention contains a surfactant. As the surfactant, any of cationic, anionic, nonionic, amphoteric, fluorine and silicon surfactants can be used.
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 sorbitan Lyolate, 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, propylene oxide adducts, etc. of the diols). Xylene alkylene alkyl ethers are preferable. The nonionic surfactant can be used in the first liquid and the second liquid. Moreover, the said nonionic surfactant may be used independently and may use 2 or more types together.

  Examples of the amphoteric surfactants include betaine-type amphoteric surfactants such as amino acid-type amphoteric surfactants, carboxyammonium betaine-type, sulfoammonium betaine-type, ammonium sulfate betaine-type, and imidazolium betaine-type. Patent No. 3,843,368, JP-A-59-49535, JP-A-63-236546, JP-A-5-303205, JP-A-8-262742, JP-A-10-282619, etc. What is described can be used conveniently. 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.), specifically, N-aminoacyl acid and salts thereof into which a long chain acyl group has been introduced. The amphoteric surfactant may be used alone or in combination of two or more.

Examples of the anionic surfactant include fatty acid salts (eg, sodium stearate, potassium oleate), alkyl sulfate esters (eg, sodium lauryl sulfate, triethanolamine lauryl sulfate), and sulfonates (eg, 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 from 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 silicone oil modified with an organic group, which has a structure in which the side chain of the siloxane structure is modified with an organic group, a structure in which both ends are modified, and a structure in which one end is modified. obtain. 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.

  In the present invention, the content of the surfactant is preferably 0.001 to 2.0%, more preferably 0.01 to 1.0% with respect to the mordant mixed solution. Further, if necessary, a surfactant may be contained in the ink receiving layer forming liquid.

Preferred surfactants in the present invention include nonionic surfactants or betaine surfactants. The content of the surfactant is 0.01 g / m ^{2 to} 0.5 g / m as the total amount of the surfactant in the mordant mixed solution and the surfactant in the ink receiving layer forming liquid contained as necessary. m ² is ^{preferable, 0.05g / m 2 ~0.3g / m} 2 is more preferable. When the surfactant content is less than 0.01 g / m ² , the wettability may be deteriorated, and when it is more than 0.5 g / m ² , the coating viscosity may be increased.

In the present invention, the ink receiving layer preferably contains a high boiling point organic solvent for curling prevention. The high-boiling organic solvent is an organic compound having a boiling point of 150 ° C. or higher at normal pressure, and is a water-soluble or hydrophobic compound. These may be liquid or solid at room temperature, and may be low molecules or polymers.
Specifically, aromatic carboxylic acid esters (for example, dibutyl phthalate, diphenyl phthalate, phenyl benzoate, etc.), aliphatic carboxylic acid esters (for example, dioctyl adipate, dibutyl sebacate, methyl stearate, dibutyl maleate) , Dibutyl fumarate, triethyl acetyl citrate, etc.), phosphate esters (eg, trioctyl phosphate, tricresyl phosphate, etc.), epoxies (eg, epoxidized soybean oil, epoxidized fatty acid methyl, etc.), alcohols (eg, stearyl) Alcohol, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, glycerol, diethylene glycol monobutyl ether (DEGMBE), triethylene glycol monobutyl ether, glycerol Methyl ether, 1,2,3-butanetriol, 1,2,4-butanetriol, 1,2,4-pentanetriol, 1,2,6-hexanetriol, thiodiglycol, triethanolamine, polyethylene glycol, etc. ), Vegetable oils (eg, soybean oil, sunflower oil, etc.) and higher aliphatic carboxylic acids (eg, linoleic acid, oleic acid, etc.).

<Support>
As the support used in the present invention, either a transparent support made of a transparent material such as plastic or an opaque support made of an opaque material such as paper can be used. In order to make use of the transparency of the ink receiving layer, it is preferable to use a transparent support or a highly glossy opaque support. Further, a read-only optical disk such as CD-ROM or DVD-ROM, a write-once optical disk such as CD-R or DVD-R, or a rewritable optical disk may be used as a support, and an ink receiving layer may be provided 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 a backlight display. Examples of the material include polyesters such as polyethylene terephthalate (PET); polysulfone, polyphenylene oxide, polyimide, polycarbonate, polyamide and the like. Of these, polyesters are preferable, and polyethylene terephthalate is particularly preferable.
Although there is no restriction | limiting in particular as thickness of the said transparent support body, 50-200 micrometers is preferable at the point which is easy to handle.

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

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

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

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

Next, the base paper used for the resin-coated paper will be described in detail.
As the base paper, wood pulp is used as a main raw material, and paper is made using synthetic pulp such as polypropylene or synthetic fibers such as nylon or polyester in addition to wood pulp as necessary. As the wood pulp, any of LBKP, LBSP, NBKP, NBSP, LDP, NDP, LUKP, and NUKP can be used, but it is preferable to use more LBKP, NBSP, LBSP, NDP, and LDP with a large amount of short fibers. 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. It is preferable that the sum with the mass% of is 30 to 70%. In addition, it is preferable that the mass% of 4 mesh remainder is 20 mass% or less.

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

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

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

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

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

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

Examples of the aqueous binder used in the back coat layer include styrene / maleate copolymer, styrene / acrylate copolymer, polyvinyl alcohol, silanol-modified polyvinyl alcohol, starch, cationized starch, casein, gelatin, carboxy Examples thereof include water-soluble polymers such as methyl cellulose, hydroxyethyl cellulose, and polyvinyl pyrrolidone, and water-dispersible polymers such as styrene butadiene latex and acrylic emulsion.
Examples of other components contained in the backcoat layer include an antifoaming agent, an antifoaming agent, a dye, a fluorescent brightening agent, a preservative, and a water-proofing agent.

  The method for producing an ink jet recording medium of the present invention comprises an ink receiving layer forming liquid containing inorganic fine particles and a water-soluble binder, and a mordant mixed solution containing a cationic polymer or a water-soluble aluminum compound and a surfactant in-line. It has at least a step of mixing to obtain a coating solution and a step of coating the coating solution on a support to form a coating layer. (1) Simultaneously when the coating solution is applied to the coating layer, (2) During the drying of the coating layer and before the coating layer exhibits reduced-rate drying, a second liquid containing a basic compound is applied and the coating layer is crosslinked and cured. The method may further include a step of forming an ink receiving layer formed by crosslinking and curing the coating layer on the support.

  Providing the ink-receiving layer crosslinked and cured in this manner is preferable from the viewpoint of ink absorbability and prevention of film cracking.

An ink receiving layer forming liquid containing inorganic fine particles (for example, vapor phase method silica) and a water-soluble binder (for example, polyvinyl alcohol) can be prepared, for example, as follows.
That is, inorganic fine particles such as gas phase method silica and a dispersant are added to water (for example, silica fine particles in water are 10 to 20% by mass), and a bead mill (for example, “KD-P manufactured by Shima Enterprise Co., Ltd.) is used. )), For example, at a high speed of 10,000 rpm (preferably 5000 to 20000 rpm), for example, for 20 minutes (preferably 10 to 30 minutes), and then dispersed in an aqueous polyvinyl alcohol (PVA) solution (for example, In order to obtain a PVA having a mass of about 1/3 of the phase silica, and dispersion is performed under the same rotation conditions as described above. 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.

The aqueous dispersion comprising the vapor phase silica and the dispersant may be prepared in advance by preparing a vapor phase silica aqueous dispersion, and the aqueous dispersion may be added 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 solution as described above.
After mixing the gas phase method silica and the dispersant, the mixture is finely divided using a disperser, whereby an aqueous dispersion having an average particle size of 50 nm or less can be obtained.

  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.

Further, a dispersant may be added to improve the dispersibility of the coating solution. It does not specifically limit as a dispersing agent, A well-known chaotic resin can be used.
The amount of the dispersant added to the inorganic fine particles is preferably 0.1% to 30%, more preferably 1% to 10%.
On the other hand, the pH of the first liquid is not particularly limited, but the pH is preferably 2.0 or more and 6.0 or less, and more preferably 3 or more and 5 or less. By forming the ink receiving layer from a coating solution having a pH of 2 or more and 6 or less, image blurring over time can be further suppressed.

  Application | coating of a 1st liquid can be performed by well-known application | coating methods, 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, a bar coater, for example.

  The second liquid is applied to the coating layer simultaneously with the application of the first liquid or during the drying of the coating layer formed by applying the first liquid and before the coating layer exhibits reduced-rate drying. . That is, after the application of the first liquid, the second liquid is preferably introduced while the coating layer exhibits a constant rate of drying. The second liquid may contain a mordant.

  The second liquid may contain a crosslinking agent and other mordant components as necessary. The second liquid can be used as an alkaline solution to promote hardening, and is preferably adjusted to pH 7.1 or higher, more preferably pH 7.5 or higher, and particularly preferably pH 7.9 or higher. If the pH is too close to the acidic side, the cross-linking reaction of the water-soluble polymer contained in the first liquid is not sufficiently performed by the cross-linking agent, resulting in the occurrence of bronzing and defects such as cracks in the ink receiving layer. is there.

  The second liquid is, for example, ion-exchanged water, a metal compound (for example, 1 to 5%), a basic compound (for example, 1 to 5%), and, if necessary, paratoluenesulfonic acid (for example, 0.5 to 3). %) And the mixture is sufficiently stirred. In addition, all "%" of each composition means solid content mass%.

  Here, “before the coating layer comes to exhibit a reduced rate of drying” usually refers to a process of several minutes immediately after coating of the coating solution, and during this time, the solvent ( The phenomenon of “constant rate drying rate” in which the content of the dispersion medium) decreases in proportion to time. About the time which shows this "constant rate drying speed", 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.

EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited by the following Example.
[Example 1]
(Production of support)
50 parts of LBKP made of acacia and 50 parts of LBKP made of aspen were beaten to 300 ml of Canadian freeness by a disc refiner to prepare a pulp slurry.

  Next, the pulp slurry obtained above was charged with 1.3% cationic starch (CATO 304L manufactured by NSC Japan), 0.15% anionic polyacrylamide (DA4104 manufactured by Seiko PMC Co., Ltd.), and alkyl ketene per pulp. After adding 0.29% dimer (size pine K, manufactured by Arakawa Chemical Co., Ltd.), 0.29% epoxidized behenamide, 0.32% polyamide polyamine epichlorohydrin (produced by Arakawa Chemical Co., Ltd .: Arafix 100), antifoaming Agent 0.12% was added.

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

After the corona discharge treatment was performed on the wire surface (back surface) side of the obtained base paper, high-density polyethylene was coated to a thickness of 25 μm using a melt extruder, and a thermoplastic resin layer comprising a mat surface was formed. (Hereinafter, this thermoplastic resin layer surface is referred to as “back surface”). The thermoplastic resin layer on the back side is further subjected to corona discharge treatment, and then, as an antistatic agent, aluminum oxide (“Alumina Sol 100” manufactured by Nissan Chemical Industries, Ltd.) and silicon dioxide (manufactured by Nissan Chemical Industries, Ltd.) Of “Snowtex O”) was dispersed in water at a mass ratio of 1: 2 so that the dry mass was 0.2 g / m ² .

  Further, after the corona discharge treatment is performed on the felt surface (surface) side where the thermoplastic resin layer is not provided, 10% of anatase-type titanium dioxide and 0.3% of ultramarine manufactured by Tokyo Ink Co., Ltd. are contained. Low density of MFR (melt flow rate) 3.8, adjusted to a content of 0.08% with a whitening agent “Whitefloor PSN conc” manufactured by Nippon Chemical Industry Co., Ltd. Polyethylene is extruded using a melt extruder so as to have a thickness of 25 μm, and a high gloss thermoplastic resin layer is formed on the surface side of the base paper (hereinafter, this high gloss surface is referred to as “front side”). A support was prepared. This support was made into a long roll body with a width of 1.5 m and a winding length of 3000 m.

(Preparation of ink receiving layer forming liquid)
(1) Gas phase method silica fine particles, (2) ion-exchanged water, (3) “Charol DC-902P” and (4) “ZA-30” in the following composition are mixed, and a bead mill (for example, KD-P ( (Manufactured by Shinmaru Enterprises Co., Ltd.)), the dispersion was heated to 45 ° C. and held for 20 hours. Thereafter, the following (5) boric acid, (6) polyvinyl alcohol solution, (7) compound A and (8) ethanol were added thereto at 30 ° C. to prepare an ink receiving layer forming liquid.
The mass ratio between the silica fine particles and the water-soluble binder (PB ratio = (1) :( 6)) was 4.45: 1, and the pH of the ink receiving layer forming liquid was 3.8, indicating acidity.

<Composition of ink receiving layer forming liquid>
(1) Gas phase method silica fine particles (inorganic fine particles) 8.9 parts (AEROSIL300SF75 manufactured by Nippon Aerosil Co., Ltd.)
(2) Ion-exchanged water 52.8 parts (3) "Charol DC-902P" (51.5% aqueous solution) 0.52 parts (dispersant, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
(4) "ZA-30" 0.48 parts (Daiichi Rare Element Chemical Co., Ltd.)
(5) Boric acid (crosslinking agent) 0.33 parts (6) Polyvinyl alcohol (water-soluble binder) solution 28.6 parts

(Composition of solution)
"PVA235" manufactured by Kuraray Co., Ltd., saponification degree 88%, polymerization degree 3500 2.0 parts ion-exchanged water 26.6 parts

(7) Compound A 0.66 parts

(8) 4.1 parts of ethanol

(Manufacture of inkjet recording media)
Was subjected to corona discharge treatment on the front surface of the support, the ink receiving layer forming liquid was flowed so as to be 173cc / m ^2, a coating solution by mixing the following mordant mixture solution at a rate of 10.8 cc / m ² It was applied while preparing (first liquid) (application step). The coating layer was dried at 80 ° C. (wind speed of 3 to 8 m / sec) with a hot air dryer until the solid content concentration of the coating layer became 24%. This coating layer exhibited a constant rate of drying during this period. Immediately after that, it was immersed in a second liquid having the following composition for 3 seconds to deposit 13 g / m ² on the coating layer (step of applying a mordant solution), and further dried at 72 ° C. for 10 minutes (drying step). ). This produced the inkjet recording medium of the present invention provided with an ink image-receiving layer having a dry film thickness of 32 μm.

<Composition of mordant mixed solution>
(1) Alphain 83 (basic polyaluminum hydroxide compound) 4.0 parts (manufactured by Daimei Chemical Co., Ltd.)
(2) Ion-exchanged water 5.3 parts (3) Polyoxyethylene lauryl ether (surfactant) 0.7 parts ("Emulgen 109P" (10% aqueous solution) manufactured by Kao Corporation, HLB value 13.6)

<Composition of the second liquid>
(1) Boric acid 0.65 parts (2) Ammonium carbonate 4.0 parts (1st grade: manufactured by Kanto Chemical Co., Inc.)
(3) Ion-exchanged water 89.4 parts (4) Polyoxyethylene lauryl ether (surfactant) 6.0 parts ("Emulgen 109P" (10% aqueous solution) manufactured by Kao Corporation, HLB value 13.6)

[Example 2]
In the mordant mixed solution of Example 1, 0.7 part of Himax SC-505 (manufactured by Hymo, cationic polymer) was added instead of 4.0 part of Alphain 83, and 10% polyoxyethylene was added to the ink receiving layer forming liquid. An ink jet recording medium was produced in the same manner as in Example 1 except that 0.44 part of an aqueous lauryl ether solution (Emulgen 109P) was added.

[Example 3]
An ink jet recording medium was prepared in the same manner as in Example 1 except that a 10% polyoxyethylene lauryl ether aqueous solution (Emulgen 109P) was added instead of a 10% polyoxyethylene lauryl ether aqueous solution (Emulgen 109P). did.

[Comparative Example 1]
In the mordant mixed solution of Example 1, ion exchange water was added instead of Emulgen 109P, and the procedure was carried out except that 0.44 parts of 10% polyoxyethylene lauryl ether aqueous solution (Emulgen 109P) was added to the ink receiving layer forming liquid. An ink jet recording medium was prepared in the same manner as in Example 1.

[Comparative Example 2]
An ink jet recording medium was produced in the same manner as in Example 1 except that ion-exchanged water was added in place of the 10% polyoxyethylene lauryl ether aqueous solution (Emulgen 109P) in the mordant mixed solution of Example 2.

[Comparative Example 3]
An ink jet recording medium was prepared in the same manner as in Example 2 except that ion-exchanged water was added instead of Himax SC-505 in the mordant mixed solution of Example 2.

The following evaluation was implemented using the obtained inkjet recording medium. The results obtained are shown in Table 1.
(Applied surface condition evaluation method)
The cracks on the surface of the ink jet recording medium after the ink receiving layer was formed were judged visually as follows.
A: No cracking B: Slight cracking observed C: Many cracks observed

(Ozone resistance evaluation method)
A cyan solid image was printed on each recording medium using an ink jet printer (“PMG-800” manufactured by Epson Corporation) loaded with a genuine ink set, and each of them was 23 ° C., 60% RH, ozone concentration 10 ppm. Samples were stored for 48 hours in an atmosphere. The cyan density was measured with a reflection densitometer (Xrite938, manufactured by Xrite), and the residual rate was determined based on the following formula from the cyan density before storage and the cyan density after storage, and judged based on the following criteria.
Residual rate (%) = (cyan density after storage / cyan density before storage) × 100

A: 65% or more B: 55-65%
C: 55% or less

  It can be seen from Table 1 that both the ozone resistance and the coated surface state can be achieved by containing a cationic polymer or basic polyaluminum hydroxide compound and a surfactant in the mordant mixed solution.

Claims (6)

  A step of obtaining an application liquid by in-line mixing an ink receptive layer forming liquid containing inorganic fine particles and a water-soluble binder and a mordant mixed solution containing a cationic polymer or a water-soluble aluminum compound and a surfactant; and And a step of forming a coating layer by applying a coating solution on a support.   The method for producing an ink jet recording medium according to claim 1, wherein at least one of the ink receiving layer forming liquid and the mordant mixed solution further contains a crosslinking agent.   The method for producing an ink jet recording medium according to claim 2, wherein the crosslinking agent is boric acid.   The method for producing an inkjet recording medium according to any one of claims 1 to 3, wherein the water-soluble binder is a polyvinyl alcohol-based resin.   The basic compound is applied to the coating layer either (1) at the same time when the coating solution is applied, or (2) during the drying of the coating layer and before the coating layer exhibits reduced-rate drying. 5. The ink receiving layer according to claim 1, further comprising a step of applying a basic solution containing the coating layer and crosslinking and curing the coating layer, and forming an ink receiving layer formed by crosslinking and curing the coating layer on the support. The manufacturing method of the inkjet recording medium as described in a term.   An ink jet recording medium manufactured by the method of manufacturing an ink jet recording medium according to claim 1.