JP2006044186A - Image recording material, material for ink jet recording and ink jet recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image recording material excellent in the ozone durability of an image. <P>SOLUTION: In the image recording material having an ink accepting layer on a substrate, the ink accepting layer contains a betaine type compound having a group containing an amino nitrogen atom and a group containing the structure of a phosphonic acid or a phosphoric acid. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ink jet recording using a liquid ink such as a water-based ink (using a dye or pigment as a coloring material) and an oil-based ink, or a solid ink which is solid at room temperature and melted and liquefied for printing. More particularly, the present invention relates to a recording material (preferably an inkjet recording sheet) having excellent image durability and an inkjet recording method.

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

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

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

For example, in Japanese Patent Application Laid-Open Nos. 10-119423 and 10-217601, etc., ink jet recording containing fine inorganic pigment particles and a water-soluble resin and having a colorant receiving layer having a high porosity is provided on a support. Sheets have been proposed.
These recording sheets, particularly ink jet recording sheets provided with a colorant-receiving layer having a porous structure using silica as inorganic pigment fine particles, are excellent in ink absorptivity due to their configuration, and form high-resolution images. It has a high ink receiving performance and can exhibit high gloss.

However, trace gases in the air, particularly ozone, cause discoloration of recorded images over time. Since the recording material composed of the colorant-receiving layer having the porous structure described above has many voids, the recorded image is easily faded by ozone gas in the air. For this reason, the resistance to ozone in the air (ozone resistance) is a very important characteristic for the recording material having the color material receiving layer having the porous structure, and it is desired to further improve the ozone resistance. Yes.
Japanese Patent Application Laid-Open No. 2004-025485 discloses an ink jet recording sheet comprising a colorant-receiving layer containing a betaine type surfactant. Specific examples of betaine type surfactants containing a carboxyl group are disclosed. However, there is no description of those containing groups containing a phosphonic acid or phosphoric acid structure.
JP 2004-025485 A

  An object of the present invention is to provide an image recording material excellent in ozone durability of an image, preferably an ink jet recording material (preferably an ink jet recording sheet) and an ink jet recording method.

The above problems have been achieved by the following means.
(1) A recording material having an ink receiving layer on a support, wherein the ink receiving layer contains a betaine type compound having a group containing an amine nitrogen atom and a group containing a phosphonic acid or phosphoric acid structure. Image recording material.
(2) The image recording material according to (1), wherein the betaine-type compound is a compound represented by the following general formula:

General formula: Z-R-Q

In the formula, Z represents a group containing an aminic nitrogen atom. Q represents a group containing a phosphonic acid or phosphoric acid structure. R represents a single bond or a linking group.
(3) The image recording material according to (1) or (2), wherein the ink receiving layer further contains a water-soluble resin.
(4) The water-soluble resin is at least one of a polyvinyl alcohol resin, a cellulose resin, a resin having an ether bond, a resin having a carbamoyl group, a resin having a carboxyl group, or gelatins. The image recording material according to (3).
(5) The image recording material according to any one of (1) to (4), wherein the ink receiving layer further contains fine particles.
(6) The image recording material according to (5), wherein the fine particles are at least one selected from silica fine particles, colloidal silica, alumina fine particles, and pseudoboehmite.
(7) The image recording material according to any one of (3) to (6), wherein the ink receiving layer contains a crosslinking agent capable of crosslinking the water-soluble resin.
(8) The image recording material according to any one of (1) to (7), wherein the ink receiving layer further contains a mordant.
(9) The ink receiving layer is a layer obtained by crosslinking and curing a coating layer coated with a coating solution containing at least fine particles, a water-soluble resin, and a crosslinking agent, and the crosslinking and curing includes (1) the coating solution. Simultaneously with the application, (2) when the coating layer formed by applying the coating solution is in the middle of drying and before the coating layer exhibits reduced-rate drying, the basic solution having a pH of 8 or more is added. The image recording material according to (7), wherein the image recording material is applied to a coating layer or a coating film.
(10) An ink jet recording material (preferably an ink jet recording sheet) characterized by using the image recording material according to any one of (1) to (9).
(11) An ink jet recording method, wherein an image is formed by printing or printing on the ink jet recording material according to (10) by finely ejecting ink using an ink jet printer.
(12) The inkjet recording method according to (11), wherein a betaine compound is contained in at least one ink. The “betaine compound” mentioned here is broader than the betaine compound described in (1), and includes anionic groups (preferably carboxyl groups and sulfonic acid groups) other than groups containing a phosphonic acid or phosphoric acid structure. . Examples of the betaine compound containing a carboxyl group or a sulfonic acid group include “betaine surfactants” described in WO 03/066756.
(13) The inkjet recording method described in (12), wherein the betaine compound is a compound represented by the general formula described in (2).

  The image recording material containing the betaine type compound of the present invention improves image fastness, particularly resistance to ozone in the air (ozone resistance).

  The ink receiving layer of the image recording material (preferably an ink jet recording sheet) of the present invention is characterized by containing a betaine-type compound containing a phosphonic acid or phosphoric acid group. However, among the betaine type compounds, the compound represented by the general formula (1) is preferably used in the present invention.

The betaine type compound further has a group containing an aminic nitrogen atom.
An aminic nitrogen atom is a nitrogen atom that can express basicity in a molecule. Examples of the basic unit containing a nitrogen atom include the following.

[1] Aminic nitrogen atom forming primary amine, secondary amine, tertiary amine, quaternary ammonium ion
[2] hydrazine nitrogen atoms such as hydrazine, semicarbazide, thiosemicarbazide, sulfohydrazide, phosphohydrazide
[3] hydroxylamine nitrogen atoms such as hydroxylamine and carbonyloxyamine
[4] Nitrogen atom in which the lone pair does not belong to the conjugated system in the 5-membered heteroaromatic ring contained in pyrazole, imidazole, triazole, tetrazole and its condensed polycyclic heteroaromatics
[5] Nitrogen atoms contained in 6-membered heteroaromatic rings such as pyridine, pyridazine, pyrimidine, pyrazine ring
[6] Nitrogen atoms conjugated with imino groups in amidine, guanidine, etc.

Q represents a group containing a phosphonic acid or phosphoric acid structure.
A group containing a phosphonic acid or phosphoric acid structure is a group consisting of a moiety obtained by removing a hydrogen atom from phosphonic acid or phosphoric acid, and is a structure in which an OH group in the group is substituted with an alkyl group, an aryl group, or the like. May be. Therefore, in the betaine type compound, such a group is bonded to a group containing an aminic nitrogen atom through a linking group or directly.
As the kind of phosphonic acid, various kinds such as alkylphosphonic acid, arylphosphonic acid, dialkylphosphonic acid, diarylphosphonic acid can be used. As phosphoric acid, any of trivalent phosphorous acid and pentavalent phosphoric acid may be used, and a part thereof may be esterified.

R represents a single bond or a linking group.
The divalent linking group is preferably a divalent linking group containing an alkylene group or an arylene group as a basic structural unit. You may contain hetero atoms, such as an oxygen atom, a sulfur atom, and a nitrogen atom, in a connection main chain part. Various substituents can be substituted on the linking group.
Examples of the substituent include an alkyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and particularly preferably 1 to 8 carbon atoms, such as methyl, ethyl, iso-propyl, tert-butyl. , N-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl, etc.), an alkenyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, particularly preferably carbon atoms). 2 to 8, for example, vinyl, allyl, 2-butenyl, 3-pentenyl, etc.), an alkynyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, particularly preferably carbon). 2 to 8, for example, propargyl, 3-pentynyl, etc.), an aryl group (preferably having 6 to 30 carbon atoms, More preferably, it has 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, and examples thereof include phenyl, p-methylphenyl, naphthyl and the like, and an amino group (preferably 0 to 20 carbon atoms, more preferably The number of carbon atoms is 0 to 12, particularly preferably 0 to 6 carbon atoms, and examples thereof include amino, methylamino, dimethylamino, diethylamino, diphenylamino, dibenzylamino, and the like, and alkoxy groups (preferably having 1 to 1 carbon atoms). 20, More preferably, it is C1-C12, Most preferably, it is C1-C8, for example, a methoxy, an ethoxy, butoxy etc.), an aryloxy group (preferably C6-C20, more preferably). It has 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, and examples thereof include phenyloxy and 2-naphthyloxy. ), An acyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as acetyl, benzoyl, formyl, pivaloyl, etc.), alkoxycarbonyl A group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms, such as methoxycarbonyl, ethoxycarbonyl, etc.), an aryloxycarbonyl group (preferably 7 to 20 carbon atoms, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 10 carbon atoms, such as phenyloxycarbonyl, etc.), acyloxy group (preferably 2 to 20 carbon atoms, more preferably Has 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms, such as acetoxy, benzoyloxy And the like. ), An acylamino group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms, such as acetylamino, benzoylamino, etc.), an alkoxycarbonylamino group (Preferably having 2 to 20 carbon atoms, more preferably having 2 to 16 carbon atoms, and particularly preferably having 2 to 12 carbon atoms, such as methoxycarbonylamino), an aryloxycarbonylamino group (preferably having a carbon number) 7 to 20, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 12 carbon atoms, such as phenyloxycarbonylamino, and the like, sulfonylamino group (preferably 1 to 20 carbon atoms, more preferably Has 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methanesulfonylamino, And sulfamoyl groups (preferably having 0 to 20 carbon atoms, more preferably 0 to 16 carbon atoms, particularly preferably 0 to 12 carbon atoms, such as sulfamoyl, methylsulfamoyl, dimethyl). Sulfamoyl, phenylsulfamoyl, etc.), a carbamoyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as carbamoyl, methyl Carbamoyl, diethylcarbamoyl, phenylcarbamoyl, etc.), alkylthio groups (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methylthio, ethylthio, etc. An arylthio group (preferably having 6 to 6 carbon atoms). 0, more preferably 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenylthio, and the like, a sulfonyl group (preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms). Particularly preferably, it has 1 to 12 carbon atoms, such as mesyl, tosyl, etc.), sulfinyl group (preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 1 carbon atoms). 12 such as methanesulfinyl, benzenesulfinyl, etc.), a ureido group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, for example, ureido , Methylureido, phenylureido, etc.), phosphoric acid amide groups (preferably having 1 to 20 carbon atoms, more preferably 1 to carbon atoms). 16, particularly preferably 1 to 12 carbon atoms, such as diethyl phosphoric acid amide and phenyl phosphoric acid amide. ), Hydroxy group, mercapto group, halogen atom (eg fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfone group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group, Heterocyclic group (preferably having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, and the hetero atom includes, for example, a nitrogen atom, an oxygen atom and a sulfur atom, and specifically includes, for example, imidazolyl and pyridyl. Quinolyl, furyl, thienyl, piperidyl, morpholino, benzoxazolyl, benzoimidazolyl, benzothiazolyl, carbazolyl, azepinyl, etc.), silyl group (preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, Particularly preferably, it has 3 to 24 carbon atoms, such as trimethylsilyl, Li phenyl silyl and the like.), And the like. These substituents may be further substituted. When there are two or more substituents, they may be the same or different. If possible, they may be linked to each other to form a ring.

Basically, the compound represented by the general formula (1) has a molecule of betaine due to a cationic property (group) expressed from an amine nitrogen atom and an anionic property (group) expressed by a phosphorus atom-containing acid. It is characterized by being a type compound. Among them, it is preferable that an oil-solubilizing group having 8 or more carbon atoms that imparts surface activity to the molecule is substituted.
The oil-solubilizing group can be used in various forms. For example, an alkyl group (which may be substituted, preferably a group having 1 to 20 carbon atoms. For example, a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, an octyl group, a dodecyl group, a cetyl group, a stearyl group. Oleyl group, etc.), aryl group (which may be substituted, preferably a group having 6 to 20 carbon atoms, such as phenyl group, tolyl group, xylyl group, naphthyl group, cumyl group, dodecylphenyl group, etc.), A heterocyclic group (which may be substituted; preferably a group having 2 to 20 carbon atoms; for example, a pyridyl group, a quinolyl group, etc.), which may be linked to each other to form a cyclic structure; Among these, an alkyl group is particularly preferable.

Moreover, the compound of General formula (1) may form the polymer compound containing the partial structure. In the case of a polymer, a pendant polymer whose partial structure is contained in a vinyl polymerizable group may be used, or a polymer containing a structural site in the main chain.
In the case of a polymer, a water-soluble polymer is most preferable, and the weight average molecular weight is 1000 to 1000000, preferably 5000 to 100,000.

  Preferred examples of the compound of the present invention are enumerated below, but the present invention is of course not limited thereto.

Betaine type compounds of the present invention is an image recording material (preferably inkjet recording sheet) 0.0001~10g / m ² on, preferably 0.001 to 5 g / m ^2, particularly preferably 0.01 to 2 g / m ² contained. The additive layer can be added to any layer when two layers of coating liquid are used when the inkjet recording sheet is applied, but it is preferably added to the uppermost layer from the viewpoint of applicability.

  When the betaine-type compound of the present invention is contained in the ink receiving layer, a water-soluble organic solvent such as an alcohol compound (methanol, ethanol, isopropyl alcohol, ethylene glycol, diethylene glycol, diethylene glycol monobutyl ether, polyethylene glycol, polypropylene glycol, glycerin, Diglycerin, trimethylolpropane, trimethylolbutane, etc.), ether compounds (tetrahydrofuran, dioxane, etc.), amide compounds (dimethylformamide, dimethylacetamide, N-methylpyrrolidone, etc.), ketone compounds (acetone, etc.), etc. are mixed and water is mixed. You may add in the state which raised affinity to.

  When the betaine-type compound of the present invention does not have sufficient water solubility, a hydrophobic organic solvent such as an ester compound (such as ethyl acid, dioctyl adipate, butyl phthalate, methyl stearate, tricresyl phosphate, etc.) , Ether compounds (anisole, hydroxyethoxybenzene, hydroquinone dibutyl ether, etc.), hydrocarbon compounds (toluene, xylene, diisopropylnaphthalene, etc.), amide compounds (N-butylbenzenesulfonamide, stearic acid amide, etc.), alcohol compounds (2 -Ethylhexyl alcohol, benzyl alcohol, phenethyl alcohol, etc.), a ketone compound (hydroxyacetophenone, benzophenone, cyclohexane, etc.), or the above-mentioned water-soluble organic solvent may be mixed and added. The form when added may be oil droplets, latex, solid dispersion, polymer dispersion or the like.

(Water-soluble resin)
In the ink jet recording material (preferably ink jet recording sheet) of the present invention, the ink receiving layer preferably contains a water-soluble resin together with a mordant and a betaine type compound.

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.], cellulosic 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.
Further, resins having a carboxyl group as a dissociable group, particularly polyacrylates, maleic resins, alginates, gelatins and the like can also be mentioned.
Among the water-soluble resins, polyvinyl alcohol resins, cellulose resins, resins having an ether bond, resins having a carbamoyl group, resins having a carboxyl group, or gelatins are preferable.

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. And the like.
Examples of water-soluble resins other than polyvinyl alcohol resins include compounds described in JP-A-11-165461 (0011) to (0014).
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.

(Fine particles)
In the ink jet recording sheet of the present invention, the ink receiving layer preferably contains fine particles together with a betaine type compound, and more preferably contains a water-soluble resin and fine particles together with the betaine type compound. When the ink receiving layer contains fine particles, a porous structure is obtained, thereby improving the ink absorption performance. In particular, when the solid content of the fine particles in the ink receiving layer is 50% by mass or more, more preferably more than 60% by mass, it becomes possible to form a more favorable porous structure, and sufficient ink absorptivity. Ink jet recording sheets having the above are preferable. Here, the solid content in the ink receiving layer of fine particles is a content calculated based on components other than water in the composition constituting the ink receiving layer.

  As the fine particles, organic fine particles and inorganic fine particles can be used, but it is preferable to contain inorganic fine particles from the viewpoint of ink absorbability and image stability.

  The organic fine particles are preferably polymer fine particles obtained by, for example, emulsion polymerization, microemulsion polymerization, soap-free polymerization, seed polymerization, dispersion polymerization, suspension polymerization, and the like. Polyethylene, polypropylene, polystyrene, polyacrylate, polyamide, silicon resin , Phenol resin, natural polymer powder, latex or emulsion polymer fine particles, and the like.

Examples of the inorganic fine particles include silica fine particles, colloidal silica, titanium dioxide, barium sulfate, calcium silicate, zeolite, kaolinite, halloysite, mica, talc, calcium carbonate, magnesium carbonate, calcium sulfate, pseudoboehmite, zinc oxide, water. Examples thereof include zinc oxide, alumina fine particles, 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 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 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 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. 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 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 sheets 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.

In the present invention, the inorganic fine particles are preferably alumina fine particles, alumina hydrate, a mixture or a composite thereof. 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 inkjet recording sheet, for example, JP-A-10-81064, JP-A-10-119423, JP-A-10-157277, JP-A-10-217601, JP-A-11-348409, JP-A-2001-2001. 138621, 2000-43401, 2000-21235, 2000-309157, 2001-96897, 2001-138627, JP-A-11-91242, 8-2087, 8-2090 No. 8-2091, No. 8-2093, No. 8-174992, No. 11-192777, JP-A No. 2001-301314, etc. can be preferably used.

In the present invention, the water-soluble resin and the fine particles, which mainly constitute the ink-receiving layer, 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 to be combined with fine particles, particularly silica fine particles, is important. When the gas phase method silica is used, the water-soluble resin is preferably a polyvinyl alcohol resin, more preferably a polyvinyl alcohol resin having a saponification degree of 70 to 100%, and a saponification degree of 80 to 99.5. % Of polyvinyl alcohol resin is particularly preferable.

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

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

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

  In the present invention, the ink receiving layer 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 voids are easily blocked by the resin, and from the viewpoint of preventing the ink absorbency from being lowered due to the decrease in the void ratio, the ratio is 1.5: 1 to 10: 1. 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. 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 of the ink jet recording sheet of the present invention includes a coating layer containing fine particles and a water-soluble resin, and further includes a cross-linking agent capable of cross-linking the water-soluble resin, and a cross-linking reaction between the cross-linking agent and the water-soluble resin. An embodiment that is a cured porous layer is preferred.

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), can be mentioned five borate _{(e.g., KB 5 O 8 · 4H 2} O, Ca 2 B 6 O 11 · 7H 2 O, CsB 5 O 5) or the like. Among them, Of these, borax, boric acid, and 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 the 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 2,983,611; described in US Pat. No. 3,100,704 Carboximide compounds; Epoxy compounds such as glycerol triglycidyl ether; Ethyleneimino compounds such as 1,6-hexamethylene-N, N′-bisethyleneurea; Halogenated carboxaldehydes such as mucochloric acid and mucophenoxycyclolic acid Compounds; dioxane compounds such as 2,3-dihydroxydioxane; metal-containing compounds such as titanium lactate, aluminum sulfate, chromium alum, potash alum, zirconyl acetate, chromium acetate, polyamine compounds such as tetraethylenepentamine, adipine Hydrazide compounds such as 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.

The application of the cross-linking agent is preferably performed as described below when a boron compound is taken as an example. That is, the ink-receiving layer is coated with a coating liquid (hereinafter sometimes referred to as a first coating liquid) containing a fine particle, a water-soluble resin containing polyvinyl alcohol, and a boron compound in addition to the betaine type compound. A layer obtained by crosslinking and curing the layer, wherein the crosslinking and curing is (1) when the coating solution is applied, and (2) during the dry coating of the coating layer formed by coating the coating solution. At any time before the layer exhibits reduced-rate drying, a mordant described in detail below and a basic solution having a pH of 8 or more (hereinafter sometimes referred to as a second coating solution) are applied to the coating layer or coating film. Is done.
1-50 mass% is preferable with respect to water-soluble resin, and, as for the usage-amount of a crosslinking agent, 5-40 mass% is more preferable.

(mordant)
In the present invention, it is preferable that a mordant is further contained in the ink receiving layer in order to improve water resistance and aging resistance of the formed image.
However, in the present invention, it is preferable to use a mordant having a low molecular weight component having a molecular weight of 500 or less and 1% or less, preferably 0.1% or less. This molecular weight can be quantified by gel permeation chromatography (GPC).

  As the mordant, a cationic polymer (cationic mordant) or an inorganic mordant is preferable as the organic mordant, and the liquid magenta having an anionic dye as a coloring material can be obtained by making the mordant present in the ink receiving layer. It can interact to stabilize the colorant 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.

  The mordant may be added to the coating liquid (first coating liquid) containing fine particles and a water-soluble resin in addition to the betaine type compound, or when there is a concern of causing aggregation between the fine particles, the second coating is applied. It is possible to use a method in which it is contained in a liquid and applied.

As the cationic mordant, a polymer mordant having a primary to tertiary amino group or a quaternary ammonium base as a cationic group is preferably used, but a cationic non-polymer mordant may also be used. it can.
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), the mordant monomer and other monomers (hereinafter, What is obtained as a copolymer or condensation polymer with "non-mordant monomer") is preferred. These polymer mordants can be used in any form of water-soluble polymer or water-dispersible latex particles.

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

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

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

  Specifically, for example, monomethyl diallyl ammonium chloride, trimethyl-2- (methacryloyloxy) ethylammonium chloride, triethyl-2- (methacryloyloxy) ethylammonium chloride, trimethyl-2- (acryloyloxy) ethylammonium chloride, triethyl- 2- (acryloyloxy) ethylammonium chloride, trimethyl-3- (methacryloyloxy) propylammonium chloride, triethyl-3- (methacryloyloxy) propylammonium chloride, trimethyl-2- (methacryloylamino) ethylammonium chloride, triethyl-2- (Methacryloylamino) ethylammonium chloride, trimethyl-2- (acryloylamino) ethyl Ammonium chloride, triethyl-2- (acryloylamino) ethylammonium chloride, trimethyl-3- (methacryloylamino) propylammonium chloride, triethyl-3- (methacryloylamino) propylammonium chloride, trimethyl-3- (acryloylamino) propylammonium chloride Triethyl-3- (acryloylamino) propylammonium chloride;

N, N-dimethyl-N-ethyl-2- (methacryloyloxy) ethylammonium chloride, N, N-diethyl-N-methyl-2- (methacryloyloxy) ethylammonium chloride, N, N-dimethyl-N-ethyl- 3- (acryloylamino) propylammonium chloride, trimethyl-2- (methacryloyloxy) ethylammonium bromide, trimethyl-3- (acryloylamino) propylammonium bromide, trimethyl-2- (methacryloyloxy) ethylammonium sulfonate, trimethyl-3- And (acryloylamino) propylammonium acetate.
In addition, examples of copolymerizable monomers include N-vinylimidazole and N-vinyl-2-methylimidazole.

In addition, allylamine, diallylamine, its derivatives, salts and the like can be used. Examples of such compounds include allylamine, allylamine hydrochloride, allylamine acetate, allylamine sulfate, diallylamine, diallylamine hydrochloride, diallylamine acetate, diallylamine sulfate, diallylmethylamine and salts thereof (for example, Hydrochloride, acetate, sulfate, etc.), diallylethylamine and salts thereof (for example, hydrochloride, acetate, sulfate, etc.), diallyldimethylammonium salt (chloride, acetic acid as counter anions of the salt) Ion sulfate ions, etc.). In addition, since these allylamines and diallylamine derivatives are inferior in polymerizability in the amine form, they are generally polymerized in the form of a salt and desalted as required.
In addition, a unit such as N-vinylacetamide, N-vinylformamide or the like, which is converted into a vinylamine unit by hydrolysis after polymerization, and a salt thereof can also be used.

The non-mordant monomer does not contain a basic or cationic moiety such as a primary to tertiary amino group and a salt thereof, or a quaternary ammonium base, and does not show an interaction with a dye in an inkjet ink. Or the monomer which interaction is substantially small is said.
Examples of the non-mordant monomer include (meth) acrylic acid alkyl ester; (meth) acrylic acid cycloalkyl ester such as cyclohexyl (meth) acrylate; (meth) acrylic acid aryl ester such as phenyl (meth) acrylate; Aralkyl esters such as (meth) benzyl acrylate; Aromatic vinyls such as styrene, vinyl toluene and α-methylstyrene; Vinyl esters such as vinyl acetate, vinyl propionate and vinyl versatic acid; Allyl esters such as allyl acetate Halogen-containing monomers such as vinylidene chloride and vinyl chloride; vinyl cyanide such as (meth) acrylonitrile; olefins such as ethylene and propylene; and the like.

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

Further, as the polymer mordant, polydiallyldimethylammonium chloride, polymethacryloyloxyethyl-β-hydroxyethyldimethylammonium chloride, polyethyleneimine, polyallylamine and derivatives thereof, polyamide-polyamine resin, cationized starch, dicyandiamide formalin condensate, dimethyl Addition of 2-hydroxypropylammonium salt polymer, polyamidine, polyvinylamine, dicyandiamide-formalin polycondensate, dicyanamide-cachinic resin, dicyanamide-diethylenetriamine-polycondensate, polyamine-type katine resin, epichlorohydrin-dimethylamine addition polymer, dimethyldiallylammonium phosphorus chloride -SO ₂ copolymers, diallylamine salt -SO ₂ copolymer, Quaternary ammonium base-substituted alkyl group having an ester moiety (meth) acrylate-containing polymers, styryl polymers having a quaternary ammonium base-substituted alkyl group may be mentioned as being also preferred.

  Specific examples of the polymer mordant include JP-A Nos. 48-28325, 54-74430, 54-124726, 55-22766, 55-142339, 60-23850, and 60. -23851, 60-23852, 60-23853, 60-57836, 60-60643, 60-118834, 60-122940, 60-122941, 60-122294 No. 60-235134, JP-A-1-161236, U.S. Pat.Nos. 2,484,430, 2,548,564, 3,148,061, 3,309,690, 4,115,124, 4,124,386, 4,193,800, 4,273,853, JP 4282305, JP 4450224, JP-A-1-16123. 10-81064, 10-119423, 10-157277, 10-217601, 11-348409, JP-A-2001-138621, 2000-43401, 2000-212235 2000-309157, 2001-96897, 2001-138627, JP-A-11-91242, 8-2087, 8-2090, 8-2091, 8-2093, JP-A-8-174992, JP-A-11-192777, JP-A-2001-301314, JP-B-5-35162, JP-A-5-35163, JP-A-5-35164, JP-A-5-88846, JP-A-7-118333 JP-A-2000-344990, Japanese Patent Nos. 2648847, 2666177, etc. Etc. The. Of these, polyallylamine and derivatives thereof are particularly preferable.

  As the organic mordant in the present invention, polyallylamine having a mass average molecular weight of 100,000 or less and derivatives thereof are preferable.

  In the present invention, various known allylamine polymers and derivatives thereof can be used as polyallylamine or derivatives thereof. Examples of such derivatives include salts of polyallylamine and acids (acids include inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid and nitric acid, methanesulfonic acid, toluenesulfonic acid, acetic acid, propionic acid, cinnamic acid, (meth) Organic acids such as acrylic acid, or combinations thereof, or salts of only a part of allylamine), derivatives of polyallylamine by polymer reaction, copolymers of polyallylamine and other copolymerizable monomers Specific examples of the monomer include (meth) acrylic acid esters, styrenes, (meth) acrylamides, acrylonitrile, vinyl esters and the like.

  Specific examples of polyallylamine and derivatives thereof include JP-B-62-31722, JP-B-2-14364, JP-B-63-43402, 63-43403, 63-45721, 63-29881, Japanese Patent Publication No. 1-26362, No. 2-56365, No. 2-57084, No. 4-41686, No. 6-2780, No. 6-45649, No. 6-15592, No. 4-68622, Patents No. 3199227, No. 3008369, JP-A-10-330427, JP-A-11-21321, JP-A-2000-281728, JP-A-2001-106736, JP-A-62-256801, JP-A-7-173286, 7-213897, 9-235318, 9-302026, 11-21321, WO99 / 2190 No., No. WO99 / nineteen thousand three hundred and seventy-two, JP-A-5-140213, compounds described in JP Kohyo No. 11-506488, and the like.

In the present invention, an inorganic mordant can be used as the mordant, and examples thereof include polyvalent water-soluble metal salts and hydrophobic metal salt compounds.
Specific examples of the inorganic mordant include, for example, magnesium, aluminum, calcium, scandium, titanium, vanadium, manganese, iron, nickel, copper, zinc, gallium, germanium, strontium, yttrium, zirconium, molybdenum, indium, barium, lanthanum, Examples thereof include salts or complexes of metals selected from cerium, praseodymium, neodymium, samarium, europium, gadolinium, dysproprosium, erbium, ytterbium, hafnium, tungsten, and bismuth.

  Specifically, for example, calcium acetate, calcium chloride, calcium formate, calcium sulfate, barium acetate, barium sulfate, barium phosphate, manganese chloride, manganese acetate, manganese formate dihydrate, manganese ammonium sulfate hexahydrate, chloride chloride Dicopper, ammonium copper (II) chloride dihydrate, copper sulfate, cobalt chloride, cobalt thiocyanate, cobalt sulfate, nickel sulfate hexahydrate, nickel chloride hexahydrate, nickel acetate tetrahydrate, nickel sulfate Ammonium hexahydrate, nickel amidosulfate tetrahydrate, aluminum sulfate, aluminum alum, basic polyaluminum hydroxide, aluminum sulfite, aluminum thiosulfate, polyaluminum chloride, aluminum nitrate nonahydrate, aluminum chloride hexahydrate , Ferrous bromide, ferrous chloride, ferric chloride Ferrous sulfate, ferric sulfate, zinc phenolsulfonate, zinc bromide, zinc chloride, zinc nitrate hexahydrate, zinc sulfate, titanium tetrachloride, tetraisopropyl titanate, titanium acetylacetonate, titanium lactate, zirconium acetyl Acetonate, zirconyl acetate, zirconyl sulfate, ammonium zirconium carbonate, zirconyl stearate, zirconyl octylate, zirconyl nitrate, zirconium oxychloride, zirconium zirconium chloride, chromium acetate, chromium sulfate, magnesium sulfate, magnesium chloride hexahydrate, citric acid Magnesium nonahydrate, sodium phosphotungstate, sodium tungsten citrate, 12 tungstophosphoric acid n hydrate, 12 tungstosilicic acid 26 hydrate, molybdenum chloride, 12 molybdophosphoric acid n hydrate, gallium nitrate , Strontium nitrate, strontium nitrate, yttrium acetate, yttrium chloride, yttrium nitrate, indium nitrate, lanthanum nitrate, lanthanum chloride, lanthanum acetate, lanthanum benzoate, cerium chloride, cerium sulfate, cerium octylate, praseodymium nitrate, neodymium nitrate, nitric acid Examples include samarium, europium nitrate, gadolinium nitrate, dysprosium nitrate, erbium nitrate, ytterbium nitrate, hafnium chloride, and bismuth nitrate.

In the present invention, the inorganic mordant is preferably an aluminum-containing compound, a titanium-containing compound, a zirconium-containing compound, or a group IIIB series metal compound (salt or complex) of the periodic table.
Mordant amount contained in the ink receiving layer in the present invention is preferably from ^{0.01g / m 2 ~5g / m 2} , 0.1g / m 2 ~3g / m 2 is more preferable.

(Other ingredients)
The ink-jet recording material of the present invention (preferably an ink-jet recording sheet) may further contain various known additives such as acids, ultraviolet absorbers, antioxidants, fluorescent brighteners, monomers, and polymerization initiation as necessary. Agents, polymerization inhibitors, anti-bleeding agents, preservatives, viscosity stabilizers, antifoaming agents, surfactants, antistatic agents, matting agents, anti-curling agents, water-proofing agents, and the like.

  In the present invention, the ink receiving layer may contain an acid. By adding an acid, the surface pH of the ink receiving layer is adjusted to 3 to 8, preferably 5 to 7.5. This is preferable because yellowing resistance of the white background portion is improved. The surface pH is measured by the A method (coating method) of the surface PH measurement defined by the Japan Paper Pulp Technology Association (J.TAPPI). For example, the measurement can be performed using a paper PH measurement set “Type MPC” manufactured by Kyoritsu Riken Co., Ltd., which corresponds to the method A.

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

  The above acids can be metal salts (eg sodium, potassium, calcium, cesium, zinc, copper, iron, aluminum, zirconium, lanthanum, yttrium, magnesium, strontium, cerium, etc.) or amine salts (eg ammonia, triethylamine, tri Butylamine, piperazine, 2-methylpiperazine, polyallylamine, etc.).

In the present invention, it is preferable that the ink receiving layer contains a preservability improving agent such as an ultraviolet absorbent, an antioxidant, or a bleeding inhibitor.
These UV absorbers, antioxidants, and bleeding inhibitors include alkylated phenol compounds (including hindered phenol compounds), alkylthiomethylphenol compounds, hydroquinone compounds, alkylated hydroquinone compounds, tocopherol compounds, thiodiphenyl ether compounds, 2 Compounds having the above thioether bonds, bisphenol compounds, O-, N- and S-benzyl compounds, hydroxybenzyl compounds, triazine compounds, phosphonate compounds, acylaminophenol compounds, ester compounds, amide compounds, ascorbic acid, amine antioxidants Agent, 2- (2-hydroxyphenyl) benzotriazole compound, 2-hydroxybenzophenone compound, acrylate, water-soluble or hydrophobic metal salt, organometallic compound, metal complex, Ndardamine compounds (including TEMPO compounds), 2- (2-hydroxyphenyl) 1,3,5, -triazine compounds, metal deactivators, phosphite compounds, phosphonite compounds, hydroxyamine compounds, nitrone compounds, peroxidation Scavenger, polyamide stabilizer, polyether compound, basic auxiliary stabilizer, nucleating agent, benzofuranone compound, indolinone compound, phosphine compound, polyamine compound, thiourea compound, urea compound, hydrazide compound, amidine compound, sugar compound, hydroxybenzoic acid Acid compounds, dihydroxybenzoic acid compounds, trihydroxybenzoic acid compounds and the like can be mentioned.

  Among these, alkylated phenol compounds, compounds having two or more thioether bonds, bisphenol compounds, ascorbic acid, amine-based antioxidants, water-soluble or hydrophobic metal salts, organometallic compounds, metal complexes, hindered amine compounds, Hydroxyamine compounds, polyamine compounds, thiourea compounds, hydrazide compounds, hydroxybenzoic acid compounds, dihydroxybenzoic acid compounds, trihydroxybenzoic acid compounds and the like are preferable.

  Specific examples of the compounds are JP-A-10-182621, JP-A-2001-260519, JP-B-4-34953, JP-B-4-34513, JP-A-11-170686, JP-B-4-34512, EP1138509. No. 60-67190, No. 7-276808, No. 2001-94829, No. 47-10537, No. 58-111942, No. 58-212844, No. 59-19945, 59-46646, 59-109055, 63-53544, JP-B 36-10466, 42-26187, 48-30492, 48-31255, 48-41572, 48-54965, 50-10726, U.S. Pat.Nos. 2,719,086, 3,707,375, 3,7 No. 4,919, the 4,220,711 Patent,

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

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

The other components may be used alone or in combination of two or more. These other components may be added after being water-solubilized, dispersed, polymer-dispersed, emulsified or oil-dropped, or may be encapsulated in microcapsules. In the ink jet recording sheet of the present invention, the amount of the other ingredients, preferably 0.01 to 10 g / m ^2.

  Further, for the purpose of improving the dispersibility of the inorganic fine particles, the inorganic surface may be treated with a silane coupling agent. Examples of the silane coupling agent include an organic functional group (for example, vinyl group, amino group (primary to tertiary amino group, quaternary ammonium base), epoxy group, mercapto, in addition to the site for coupling treatment. Group having a group, a chloro group, an alkyl group, a phenyl group, an ester group, etc.).

In the present invention, the ink receiving layer coating solution preferably 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, polyoxyethylene 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, and the like of the diols), and polyoxy Ruki alkylene alkyl ethers are preferable. The nonionic surfactant can be used in the first coating solution and the second coating solution. Moreover, the said nonionic surfactant may be used independently and may use 2 or more types together.

  Examples of the amphoteric surfactants include amino acid types. For example, U.S. Pat. No. 3,843,368, JP-A 59-49535, JP-A 63-236546, JP-A 5-303205, and 8 -262742, 10-282619, Japanese Patent No. 2514194, Japanese Patent No. 2759795, Japanese Patent Application Laid-Open No. 2000-351269, and the like can be suitably used. The amphoteric surfactants may be used alone or in combination of two or more.

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

Examples of the fluorosurfactant include compounds derived 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.

  As the silicon-based surfactant, silicon oil modified with an organic group is preferable, and a structure in which a side chain of a siloxane structure is modified with an organic group, a structure in which both ends are modified, and a structure in which one end is modified can be taken. 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, when a surfactant other than the betaine type compound is used, the content of the surfactant is preferably 0.001 to 2.0%, preferably 0.01 to 2.0% with respect to the ink receiving layer coating solution. 1.0% is more preferable. Further, when coating is performed using two or more liquids as the ink receiving layer coating liquid, it is preferable to add a surfactant to each coating liquid.

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 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.

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 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 / 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.

(Preparation of inkjet recording sheet)
The ink receiving layer of the ink jet recording sheet of the present invention includes, for example, a first coating liquid (hereinafter referred to as “coating liquid (A) on the support surface containing fine particles, a water-soluble resin, and a crosslinking agent in addition to a betaine type compound. ) ", And (1) at the same time as the application, (2) during the drying of the coating layer formed by the coating, before the coating layer exhibits a reduced rate of drying After applying a second coating solution containing at least a mordant and having a pH of 8 or more (hereinafter sometimes referred to as “coating solution (B)”), the coating layer provided with the second coating solution is crosslinked. It is preferably formed by a curing method (Wet-on-Wet method).
Providing an ink receiving layer that has been crosslinked and cured in this manner is preferable from the viewpoints of ink absorptivity and prevention of film cracking.

  This is preferable because a large amount of mordant is present near the surface of the ink receiving layer, so that the ink-jet coloring material is sufficiently mordanted and the water resistance of characters and images after printing is improved. A part of the mordant may be contained in the coating liquid (A). In that case, the mordants of the coating liquid (A) and the coating liquid (B) may be the same or different.

In the present invention, the ink-receiving layer coating liquid (coating liquid (A)) containing at least fine particles (for example, vapor phase method silica) and a water-soluble resin (for example, polyvinyl alcohol) is, for example, as follows. Can be prepared. That is,
Vapor phase silica fine particles and a dispersant are added to water (for example, silica fine particles in water are 10 to 20% by mass), and a high-speed rotating wet colloid mill (for example, “Clairemix” manufactured by M Technique Co., Ltd.) 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, followed by a crosslinking agent (boron compound) and a polyvinyl alcohol (PVA) aqueous solution. It can be prepared by adding (for example, PVA having a mass of about 1/3 of the above-mentioned vapor phase silica), adding a betaine type compound, and dispersing under the same rotation conditions as described above. 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.

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.
As a disperser used for obtaining the aqueous dispersion, various types of conventionally known dispersers such as a high-speed rotary disperser, a medium agitating disperser (ball mill, sand mill, etc.), an ultrasonic disperser, a colloid mill disperser, and a high pressure disperser. 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 the aforementioned mordants. It is also preferable to use a silane coupling agent as the dispersant.
The amount of the dispersant added to the fine particles is preferably 0.1% to 30%, more preferably 1% to 10%.

  The ink receiving layer coating solution is applied by a known coating method such as an extrusion die coater, an air doctor coater, a bread coater, a rod coater, a knife coater, a squeeze coater, a reverse roll coater, or a bar coater. it can.

  The coating liquid (B) is applied to the coating layer simultaneously with or after the coating of the ink receiving layer coating liquid (coating liquid (A)), and the coating liquid (B) is applied to the coating layer after coating. May be applied before the rate of decrease in drying rate is reached. That is, after the application of the ink receiving layer coating liquid (coating liquid (A)), the mordant is preferably introduced while the coating layer exhibits a constant rate of drying.

  Here, “before the coating layer comes to exhibit a decreasing rate of drying” usually refers to a process of several minutes immediately after the coating of the coating liquid for the ink-receiving layer. This shows the phenomenon of “constant rate drying rate” in which the content of the solvent (dispersion medium) in the 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 coating solution, the coating layer is dried until the coating layer exhibits a reduced rate of drying. This drying is generally performed at 50 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 the above range is usually appropriate.

  As a method of giving before the said 1st application layer comes to show a decreasing rate drying rate, [1] The method of further apply | coating a coating liquid (B) on an application layer, [2] By methods, such as a spray Examples of the spraying method include [3] a method of immersing the support on which the coating layer is formed in the coating solution (B).

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

  After application of the mordant solution (coating liquid (B)), it is generally heated at 40 to 180 ° C. for 0.5 to 30 minutes to be dried and cured. Especially, it is preferable to heat at 40-150 degreeC for 1 to 20 minutes.

  When the mordant solution (coating liquid (B)) is applied simultaneously with the application of the ink receiving layer coating liquid (coating liquid (A)), the ink receiving layer coating liquid (coating liquid (A)) and the mordant solution ( The coating solution (B)) is simultaneously coated (multilayer coating) on the support so that the ink receiving layer coating solution (coating solution (A)) is in contact with the support, and then dried and cured to receive the ink. A layer can be formed.

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

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

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

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

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

In the case of ink jet recording, the thickness of the ink receiving layer needs to have an absorption capacity sufficient to absorb all of the droplets, and therefore needs to be determined in relation to the porosity in the layer. For example, if the ink amount is 8 nL / mm ² and the porosity is 60%, a film having a layer thickness of about 15 μm or more is required.
Considering this point, in the case of ink jet recording, the layer thickness of the ink receiving layer is preferably 10 to 50 μm.

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

In addition, the ink receiving layer is preferably excellent in transparency, as a guide, the haze value when the ink receiving layer is formed on a transparent film support is preferably 30% or less, More preferably, it is 20% or less.
The haze value can be measured using a haze meter (HGM-2DP: Suga Test Instruments Co., Ltd.).

  A polymer fine particle dispersion may be added to a constituent layer (for example, an ink receiving layer or a back layer) of the ink jet recording sheet 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 Nos. 62-245258, 62-1316648, and 62-110066. If a polymer fine particle dispersion having a low glass transition temperature (40 ° C. or lower) is added to the layer containing the mordant, cracking and curling of the layer can be prevented. Further, even when a polymer fine particle dispersion having a high glass transition temperature is added to the back layer, curling can be prevented.

Further, the inkjet recording sheet of the present invention is disclosed in JP-A Nos. 10-81064, 10-119423, 10-157277, 10-217601, 11-348409, and JP-A-2001-138621. 2000-43401, 2000-2111235, 2000-309157, 2001-96897, 2001-138627, JP-A-11-91242, 8-2087, 8-2090, 8 It can also be produced by the methods described in the publications Nos. -2091 and 8-2093.
The ink received in the ink receiving layer of the present invention is not limited, and may be any of water-based ink (using a dye or pigment as a coloring material), liquid ink such as oil-based ink, and solid ink.

[Example]
Hereinafter, the present invention will be described in detail with reference to examples. However, the present invention is not limited to the examples.

(Preparation of coating liquid A for ink receiving layer)
[1] Vapor phase silica fine particles, [2] ion-exchanged water, and [3] “PAS-M-1” in the following composition are mixed and used with KD-P (manufactured by Shinmaru Enterprises Co., Ltd.). Then, after dispersing for 20 minutes at a rotational speed of 10,000 rpm, a solution containing the following [4] polyvinyl alcohol, [5] boric acid, [6] polyoxyethylene lauryl ether, and [7] ion-exchanged water is added, and the mixture is further rotated. Dispersion was again performed at several 10000 rpm for 20 minutes to prepare an ink-receiving layer coating solution A.
The mass ratio between the silica fine particles and the water-soluble resin (PB ratio = [1]: [4]) is 4.5: 1, and the pH of the ink-receiving layer coating liquid A is 3.5, indicating acidity. It was.

<Composition of ink receiving layer coating liquid A>
[1] Gas phase method silica fine particles (inorganic fine particles) 10.0 parts ("Reoceal QS-30" manufactured by Tokuyama Corporation, average primary particle diameter 7 nm)
[2] 51.7 parts of ion exchange water
[3] "PAS-M-1" (60% aqueous solution) 0.83 parts (dispersant, manufactured by Nittobo Co., Ltd.)
[4] Polyvinyl alcohol (water-soluble resin) 8% aqueous solution 27.8 parts ("PVA124" manufactured by Kuraray Co., Ltd., saponification degree 98.5%, polymerization degree 2400)
[5] Boric acid (crosslinking agent) 0.4 parts
[6] 1.2 parts of polyoxyethylene lauryl ether (surfactant) (“Emulgen 109P” (10% aqueous solution) manufactured by Kao Corporation, HLB value 13.6)
[7] Ion exchange water 33.0 parts

(Preparation of inkjet recording sheet)
After the corona discharge treatment is applied to the front surface of the support, the coating liquid A for the ink receiving layer obtained above is applied to the front surface of the support at an application amount of 200 ml / m ² using an extrusion die coater. (Applying step), and 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 reached 20%. This coating layer exhibited a constant rate of drying during this period. Immediately after that, it was immersed in a mordant solution B having the following composition for 30 seconds to deposit 20 g / m ² on the coating layer (step of applying a mordant solution), and further dried at 80 ° C. for 10 minutes (drying step). ). Thus, an inkjet recording sheet R-1 of the present invention provided with an ink receiving layer having a dry film thickness of 32 μm was produced.

<Composition of mordant coating liquid B>
[1] Boric acid (crosslinking agent) 0.65 parts
[2] 25% polyallylamine “PAA-10C” 10% aqueous solution (mordant, manufactured by Nittobo Co., Ltd.)
[3] 59.7 parts of ion exchange water
[4] Ammonium chloride (surface pH adjuster) 0.8 parts
[5] 10 parts of polyoxyethylene lauryl ether (surfactant) ("Emulgen 109P" manufactured by Kao Corporation, 2% aqueous solution, HLB value 13.6)
[6] Megafaux "F1405" 10% aqueous solution 2.0 parts (Fluorine surfactant manufactured by Dainippon Ink & Chemicals, Inc.)

  Inkjet recording sheets R-2 to R-8 having the same composition as R-1 were respectively prepared except that additives were added to the inkjet recording sheet R-1 as described below.

These ink jet recording sheets were loaded into the paper feeding portion of an ink jet printer PM-980C manufactured by EPSON, and a standard chart of the Institute of Image Electronics Engineers was printed using the ink set of PM-980C. The image fastness was evaluated using this image.
Furthermore, the same experiment was performed using a CANON inkjet printer PIXUX950i. The obtained results are shown in Tables 2 and 3 below.
(Evaluation experiment)
[1] Light fastness is measured by measuring the image density Ci immediately after printing with X-rite 310, then irradiating the image with xenon light (85,000 lux) for 10 days using an Atlas weather meter, and again The image density Cf was measured and the dye residual ratio Cf / Ci × 100 was determined and evaluated. The afterimage rate of the dye is evaluated at three points of reflection density of 1, 1.5, and 2. A is the case where the dye residual rate is 70% or more at any concentration, and B is the case where the point is less than 70%. When the concentration was less than 70%, C was designated.
[2] The heat fastness was evaluated by measuring the concentration of the sample before and after storage for 10 days under conditions of 80 ° C. and 70% RH with an X-rite 310 to determine the residual ratio of the dye. The afterimage rate of the dye is evaluated at three points of reflection density of 1, 1.5, and 2. A is the case where the dye residual rate is 90% or more at any concentration, and B is the case where the reflection point is less than 90%. The concentration of less than 90% was defined as C.
[3] For ozone resistance, the photo glossy paper on which the image is formed is left in a box where the ozone gas concentration is set to 5 ppm for 48 hours, and the image density before and after being left under ozone gas is measured by a reflection densitometer (X-Rite 310TR). ) And evaluated as a dye residual ratio. The reflection density was measured at three points of 1, 1.5 and 2.0. The ozone gas concentration in the box was set using an ozone gas monitor (model: OZG-EM-01) manufactured by APPLICS.
Evaluation was made in three stages, with A being a dye residual ratio of 80% or more at any concentration, A being 1 or 2 points being less than 80% B, and C being less than 70% at all concentrations.
The results obtained are shown in the table below.

  From the above, it is clear that the recording sheet of the present invention is excellent in light fastness, heat fastness and ozone resistance.

Claims (13)

  An image recording material having an ink receiving layer on a support, wherein the ink receiving layer contains a betaine type compound having a group containing an amine nitrogen atom and a group containing a phosphonic acid or phosphoric acid structure. Recording material. The image recording material according to claim 1, wherein the betaine-type compound is a compound represented by the following general formula.

General formula: Z-R-Q

In the formula, Z represents a group containing an aminic nitrogen atom. Q represents a group containing a phosphonic acid or phosphoric acid structure. R represents a single bond or a linking group.   The image recording material according to claim 1, wherein the ink receiving layer further contains a water-soluble resin.   4. The water-soluble resin is at least one of a polyvinyl alcohol resin, a cellulose resin, a resin having an ether bond, a resin having a carbamoyl group, a resin having a carboxyl group, or gelatins. The image recording material described in 1.   The image recording material according to claim 1, wherein the ink receiving layer further contains fine particles.   6. The image recording material according to claim 5, wherein the fine particles are at least one selected from silica fine particles, colloidal silica, alumina fine particles, and pseudoboehmite.   The image recording material according to claim 3, wherein the ink receiving layer further contains a crosslinking agent capable of crosslinking the water-soluble resin.   The image recording material according to claim 1, wherein the ink receiving layer further contains a mordant.   The ink receiving layer is a layer obtained by crosslinking and curing a coating layer coated with a coating solution containing at least fine particles, a water-soluble resin, and a crosslinking agent, and the crosslinking and curing is simultaneously performed when (1) the coating solution is applied. (2) When the coating layer formed by applying the coating solution is in the middle of drying and before the coating layer exhibits reduced-rate drying, a basic solution having a pH of 8 or more is added to the coating layer or The image recording material according to claim 7, wherein the image recording material is applied by being applied to a coating film.   An ink-jet recording material comprising the image-recording material according to claim 1.   An ink jet recording method comprising forming an image by printing or printing on the ink jet recording material according to claim 10 by finely ejecting ink using an ink jet printer.   The inkjet recording method according to claim 11, wherein the betaine compound is contained in at least one ink.   The inkjet recording method according to claim 12, wherein the betaine compound is a compound represented by the general formula according to claim 2.