JP2003103900A - Sheet for ink jet recording - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet for ink jet recording which has good ink absorbability without reducing other ink acceptive performance, which has high printing density of the image, which has excellent gloss feeling and aging bleeding and which shows high light resistance even when a solar light or a light of a fluorescent lamp is emitted. SOLUTION: The sheet for ink jet recording comprises a color material acceptive layer on the surface of a support. The color material acceptive layer is formed by using a coating liquid containing a dispersion obtained by dispersing alumina fine particles in a cationic polymer and a water soluble resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording material suitable for ink jet recording using a liquid ink such as an aqueous ink or an oil ink, or a solid ink which is solid at room temperature and is melted and liquefied to be used for printing. More specifically, the present invention relates to an inkjet recording sheet having excellent ink receiving performance.

[0002]

2. Description of the Related Art In recent years, along with the rapid development of the information industry, various information processing systems have been developed, and recording methods and apparatuses suitable for the information systems have also been developed and put into practical use. Among the above recording methods, the inkjet recording method is capable of recording on various recording materials, hardware (device)
Has been widely used not only in offices but also in so-called home use because it is relatively inexpensive, compact, and excellent in quietness.

With the recent increase in resolution of ink jet printers, it has become possible to obtain so-called photograph-like high-quality recorded matter. Further, with the development of hardware (device), various recording sheets for inkjet recording have been developed. The properties required of the recording sheet for inkjet recording are generally:
(1) quick drying (high ink absorption speed), (2) proper and uniform ink dot diameter (no bleeding), (3) good graininess, (4) High circularity of dots, (5) High color density, (6) High saturation (no dullness), (7) Good light resistance and water resistance of the printed area thing,
(8) The whiteness of the recording sheet is high, (9) the storage stability of the recording sheet is good (no yellowing coloring occurs during long-term storage), (10) deformation is difficult, and dimensional stability is good. (11) The curl is sufficiently small, and (11) the hard running property is good. In addition to the above characteristics, the photo glossy paper used for the purpose of obtaining a so-called photograph-like high-quality recorded matter may have glossiness, surface smoothness, and a photographic paper-like texture similar to silver salt photographs. Required.

Recording sheets used for ink jet recording are, for example, JP-A-55-51583, JP-A-55-144172, and JP-A-55-15039.
5 gazette, the same 56-148582 gazette, the same 56-14.
No. 8583, No. 56-148584, No. 56
-148585, 57-14091, 57-38185, 57-129778, 57-129979, 60-21908.
It is known that a pigment such as silica and a water-soluble binder described in JP-A No. 4 and JP-A No. 60-245588 are applied on a support such as paper or a plastic film. However, all of these proposed recording sheets have very low glossiness, which is insufficient for use as a photo glossy paper.

Further, in Japanese Patent Laid-Open No. 4-223190,
Is 0.1 g / m of borax or boric acid. ²The above is applied
5-20g / m on base paper²Synthetic silica and polybi
A recording layer made of nyl alcohol (PVA) was provided.
Ink jet recording paper has been proposed. The above technology
Is simply the coating strength of the recording layer with a low binder content.
The purpose is to improve it, and it is inferior in terms of gloss.
Therefore, it has been insufficient as a use of photo glossy paper.

Further, recording materials using various water-soluble polymers for obtaining gloss have been proposed. For example, JP-A-58-89391, JP-A-58-134784, JP-A-58-134786, and JP-A-60-44386.
No. 60-132785, No. 60-145.
879, 60-168651, 60-
There is known one obtained by coating polyvinyl alcohol, polyvinylpyrrolidone, gelatin or the like on a support such as paper or a plastic film described in Japanese Patent No. 171143. These recording sheets are also excellent in terms of glossiness, but inferior in terms of quick-drying ink, so that they are insufficient for use as photo glossy paper.

On the other hand, in JP-A-7-276789, JP-A-8-174992, JP-A-11-115308, JP-A-11-192777, etc., the required characteristics and manufacturing cost of the above-mentioned ink jet recording sheet are satisfied. An inkjet recording sheet is proposed. The above-mentioned JP-A-7-276789 proposes a recording sheet in which a coloring material receiving layer having a three-dimensional structure having a high porosity and formed of fine particles of an inorganic pigment and a water-soluble resin is provided on a support. Has been done. According to this configuration,
It is said that the above-mentioned ink absorbability is improved, color mixture blurring during printing is sufficiently suppressed, and an image with high resolution can be obtained. This color material receiving layer can be generally formed by containing a large amount of particles having a small particle diameter, but since the binder amount for layer formation needs to be reduced so that voids can be formed, the coating layer is rapidly dried. There is a defect that cracks occur and the transparency and appearance of the colorant receiving layer are impaired.

As a method for preventing the ink receiving layer from cracking, Japanese Patent Application Laid-Open No. 9-109545 proposes a method in which the viscosity of the binder of the coating liquid is made relatively high, but this method reduces the workability. There is a risk of uneven coating and uneven coating, and it has not reached a level that is practically effective. Further, Japanese Patent Laid-Open No. 7-76161 and 10-
Japanese Patent No. 119423 discloses a method for preventing cracks using a coating liquid composed of inorganic particles, polyvinyl alcohol (PVA), boric acid or borate, but also in this method, the viscosity of the coating liquid increases. The workability is greatly deteriorated and there is a problem in the stability of the liquid over time, which is not a practically effective level.

In the above-mentioned JP-A-10-119423 or JP-A-10-217601, a coloring material receiving layer containing fine inorganic pigment particles and a water-soluble resin and having a high porosity is provided on a support. Inkjet recording sheets have been proposed. Due to its constitution, each of the above-mentioned ink jet recording sheets is excellent in ink absorption, has a high ink receptivity capable of forming a high resolution image, and exhibits a high gloss. However, from the viewpoint of glossiness and texture, since a support having a resin coating such as polyethylene on both surfaces is used as the support, the high boiling point solvent contained in the coloring material receiving layer does not evaporate, and The solvent is not absorbed by the support. Therefore, the high boiling point solvent remains in the coloring material receiving layer as it is, and after printing, if the solvent is stored for a long time in a high temperature and high humidity environment, the solvent diffuses together with the dye in the coloring material receiving layer, and There has been a problem in that image blurring (hereinafter sometimes referred to as "temporal blurring") occurs.

Further, when silica fine particles are used in the colorant receiving layer, there is a problem that the light resistance is poor. Therefore, JP-A No. 11-321078 proposes an inkjet recording sheet using fine alumina instead of silica fine particles. However, since the recording material (recording sheet) described in the above publication uses a dispersion liquid in which alumina is dispersed with a nitrogen atom-containing monocarboxylic acid (low molecular weight), there arises a problem such as high gloss.

Japanese Unexamined Patent Publication (Kokai) No. 10-181190 proposes a method of using a coating solution containing a pigment finely dispersed and having a particle size of 500 nm or less.
Poor sharpness and gloss.

Further, JP-A-12-212135 proposes an ink jet recording sheet containing a vapor phase method silica and a cationic polymer having a constitutional unit of a polydiallylamine derivative. Not sufficient in terms of sharpness and gloss.

Further, Japanese Patent Application Laid-Open No. 12-211241 proposes a coating liquid for ink jet recording using an aqueous dispersion having a pH of 1.0 to 4.5 containing fumed silica. Cracks are likely to occur, and this also has low image print density, sharpness and gloss.

[0014]

As described above, while the color material receiving layer is strong without cracks and the like, a high-resolution image can be formed, and the formed image has water resistance, print density, The present situation is that an ink jet recording sheet having good ink absorbability, glossiness, bleeding resistance over time, and light resistance, while having an ink receiving performance such as excellent sharpness, has not yet been provided.

An object of the present invention is to solve the above-mentioned problems of the prior art and achieve the following objects. That is, firstly, the present invention has good ink absorbability, high print density of an image, excellent glossiness and bleeding resistance over time without deteriorating other ink receptive performance, and sunlight and fluorescent lamps. It is an object of the present invention to provide an inkjet recording sheet that exhibits high light resistance even under irradiation with light such as. Secondly, it is an object of the present invention to provide an inkjet recording sheet which is strong and has high resolution without generation of cracks and which is excellent in water resistance.

[0016]

Means for solving the problems Means for solving the above problems are as follows. That is, <1> An ink jet recording sheet having a colorant receiving layer on the surface of a support, wherein the colorant receiving layer comprises a dispersion obtained by dispersing fine alumina particles with a cationic polymer and a water-soluble resin. An ink jet recording sheet, which is formed using a coating liquid containing the ink.

<2> The ink jet recording sheet according to <1>, wherein the color material receiving layer contains a crosslinking agent capable of crosslinking the water-soluble resin.

<3> The alumina fine particles have an average primary particle diameter of 5 to 100 nm <1>
Alternatively, it is the inkjet recording sheet of <2>.

<4> The coloring material-receptive layer is formed by applying a coating solution containing the water-soluble resin and a dispersion obtained by dispersing the alumina fine particles in a cationic polymer on the surface of the support, and (1) Simultaneously with the coating, (2) during the drying of the coating layer formed by the coating and before the coating layer exhibits a rate of reduction drying, and (3) after the coating layer is dried to form a coating film. The inkjet recording sheet according to <2> or <3>, which is obtained by applying a solution containing the cross-linking agent and an organic mordant to at least one of the above.

<5> The inkjet recording sheet according to <2> to <4>, wherein the crosslinking agent is a boron compound.

<6> The inkjet recording sheet according to <4> or <5>, wherein the organic mordant is polyallylamine or a derivative thereof.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION << Inkjet recording sheet >>
The inkjet recording sheet of the present invention is an inkjet recording sheet having a coloring material receiving layer on the surface of a support, and the coloring material receiving layer is a dispersion liquid obtained by dispersing alumina fine particles with a cationic polymer (hereinafter referred to as a dispersion liquid). It may be referred to as "alumina dispersion liquid") and a water-soluble resin.

The ink jet recording sheet of the present invention comprises
Alumina fine particles are dispersed with a cationic polymer, and the coloring material-receptive layer is formed by using a coating liquid that suppresses agglomeration that occurs when mixed with a water-soluble resin and has excellent dispersibility and a small particle diameter. Therefore, the inkjet sheet of the present invention has high glossiness, excellent ink absorption speed and light resistance, less generation of bleeding over time, and high print density. Furthermore, by using alumina fine particles, a water-soluble resin, an organic mordant and a cross-linking agent together in the color material receiving layer, a strong color material receiving layer without cracks can be formed, and the water resistance of the formed image can be improved. And sharpness etc. can be improved.

<Coloring Material Receiving Layer> First, each material contained in the coloring material receiving layer will be described. The colorant receiving layer in the present invention contains at least alumina fine particles, a cationic polymer and a water-soluble resin, preferably further contains a crosslinking agent and an organic mordant, and may further contain various additives as required. .

(Alumina Fine Particles) The coloring material receiving layer in the present invention contains alumina fine particles. When the alumina fine particles are used for the colorant receiving layer, the ink absorption and retention efficiency are as high as when silica fine particles are used. Also,
Since the refractive index is low, it is possible to impart transparency to the colorant receiving layer by dispersing it to an appropriate particle size, high color density and good color developability can be obtained, and in comparison with the case where silica fine particles are used. It can exhibit high light resistance. The fact that the colorant receiving layer is transparent is not only for applications requiring transparency such as OHP, but also for obtaining high color density and good colorability when applied to recording sheets such as photo glossy paper. Is important in.

Examples of the alumina fine particles include anhydrous or hydrated aluminum oxide. For example, as anhydrous aluminum oxide, α-
Anhydrous alumina such as alumina, δ-alumina, θ-alumina, and χ-alumina can be used. Examples of the hydrous aluminum oxide include boehmite, gibbsite, bayerite, norstrandite, diaspore, toudite, alumina hydrate such as alumina gel. The thing etc. can be mentioned.

Of these, the preferred alumina fine particles are δ-alumina, and from the viewpoint of the production method, the alumina fine particles produced by the gas phase method, that is, in the presence of water generated during the oxyhydrogen reaction. In particular, and alumina fine particles obtained by hydrolyzing a gaseous metal chloride at a temperature characteristic of such a reaction are particularly preferable.

As the form of the fine alumina particles, for example, fine particles having a predetermined particle diameter, fine particles, fine particles, powder, fine powder, fine powder, etc. can be adopted, and the average primary particle diameter thereof is The thickness is preferably 5 to 100 nm, and particularly preferably 5 to 20 nm. When the average primary particle diameter of the alumina fine particles is within the above range, a structure having a large porosity can be formed, and the ink absorbability of the inkjet recording sheet can be improved. The average primary particle size can be measured using, for example, an electron microscope.

The content of alumina in the alumina dispersion of the present invention is preferably 60% by mass or less, more preferably 5 to 60% by mass, and particularly preferably 10 to 50% by mass. When the content of the alumina fine particles is within the above range, the alumina fine particles can be more effectively dispersed.
When the content of the alumina fine particles in the alumina dispersion is at most 60% by mass or less, for example, thickening or gelation due to a short interparticle distance between the alumina fine particles in the alumina dispersion, etc. Can be effectively suppressed.

The content of alumina in the above-mentioned alumina dispersion is 60% by mass or less, particularly in the range of 5 to 60% by mass, and when the above cationic polymer is used for dispersion,
For example, the viscosity of this alumina dispersion is 50 to 1000 m.
Since it can be easily adjusted to Pa · s, an alumina dispersion having excellent handleability can be obtained.

Examples of the aqueous dispersion medium in the present invention include non-alkaline aqueous dispersion media. Examples of the non-alkaline aqueous dispersion medium include water, methanol,
At least one aqueous solvent selected from the group consisting of ethanol, normal propyl alcohol, isopropyl alcohol, acetone, methyl ethyl ketone, ethyl acetate, and ethylene glycol, and an aqueous mixed solvent in which two or more selected from these are mixed. Etc. can be mentioned.

Examples of the water-based mixed solvent include a mixed solvent of water and isopropyl alcohol, a mixed solvent of water and methanol and / or ethanol, a mixed solvent of water, ethylene glycol and isopropyl alcohol, and water and ethylene glycol. A mixed solvent of isopropyl alcohol and ethyl acetate can be mentioned.

(Cationic Polymer) In the present invention, a cationic polymer is used to prevent agglomeration of alumina fine particles. Hereinafter, the cationic polymer added to prevent the aggregation of the alumina fine particles may be simply referred to as “aggregation inhibitor”. A cationic polymer having a primary to tertiary amino group and its salt or a quaternary ammonium salt group is preferably used as the cationic polymer used as the aggregation inhibitor, but a cationic non-polymer can also be used in combination. The above-mentioned cationic polymer is polydiallyldimethylammonium chloride, polymethacryloyloxyethyl-β-hydroxyethyldimethylammonium chloride, polyethyleneimine, polyallylamine hydrochloride, polyamide-polyamine resin, cationized starch, dicyandiamide formalin condensate, dimethyl-2.
-Hydroxypropylammonium salt polymer, polyamidine, etc., or those obtained as a homopolymer of a monomer having a cationic group such as the following quaternary ammonium salt group or a copolymer or condensation polymer with other monomer are preferable. .

As the monomer having a cationic group,
For example, trimethyl-p-vinylbenzylammonium chloride, trimethyl- (2-acrylamido-2,2
-Dimethylethyl) ammonium chloride, trimethyl- (3-acrylamido-3,3-dimethylpropyl) ammonium chloride, N-vinylimidazole, N-vinyl-2-methylimidazole, N- (3-
Examples thereof include dimethylaminopropyl) methacrylamide, hydroxylethyltrimethylammonium chloride, trimethyl- (methacrylamidopropyl) ammonium chloride and N- (1,1-dimethyl-3-dimethylaminopropyl) acrylamide.

As the other monomer, for example, alkyl (meth) acrylate ester [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, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate C1-18 (meth) acrylate Alkyl ester etc.], (meth) acrylic acid cycloalkyl ester [(meth) acrylic acid cyclohexyl etc.], (meth)
Acrylic acid aryl esters [phenyl ((meth) acrylic acid, etc.]], aralkyl esters [benzyl (meth) acrylic acid, etc.], aromatic vinyls [styrene, vinyltoluene, α-methylstyrene, etc.], vinyl esters [vinyl acetate, Vinyl propionate, vinyl versatate, etc.], allyl esters [allyl acetate, etc.], halogen-containing monomers [vinylidene chloride, vinyl chloride, etc.], vinyl cyanide [(meth) acrylonitrile, etc.], olefins [ethylene, propylene, etc. Etc.] and the like. These nonionic monomers may be used alone or in combination of two or more. Further, monomers such as methyl acrylate, ethyl acrylate, methyl methacrylate and ethyl methacrylate are preferably used.

The above-mentioned cationic polymer can be used as a water-soluble polymer or in any form such as water-dispersible latex particles. Specific examples of the cationic polymer used as the agglomeration inhibitor are the following (compound (1)
(4)) can be used suitably. However, the present invention is not limited to these.

[0037]

[Chemical 1]

The molecular weight of the cationic polymer used as the anticoagulant is 1,000 to 200 in terms of weight average molecular weight.
000 is preferable, about 2000 to 100000 is more preferable, and about 3000 to 60,000 is particularly preferable. If the molecular weight is less than 1000, the water resistance tends to be insufficient, and if it exceeds 200,000, the viscosity becomes high, and the handling suitability may be poor. The addition amount of the cationic polymer used as the aggregation inhibitor to the alumina fine particles is preferably 1 to 10% by mass,
5% by mass is more preferable. If the addition amount is less than 1% by mass, the dispersibility may be poor, and if it exceeds 10% by mass, the color density may decrease when printed on an inkjet recording sheet, which is not preferable.

Further, in the preparation of the dispersion liquid comprising the above-mentioned alumina fine particles and the anti-agglomeration agent, an aqueous dispersion of alumina fine particles may be prepared in advance and the aqueous dispersion liquid may be added to the aqueous solution of the anti-aggregation agent, or the anti-aggregation agent may be prevented. The aqueous solution of the agent may be added to the aqueous dispersion of fine alumina particles, or may be mixed at the same time. Also,
Instead of the aqueous dispersion of alumina fine particles, powdery alumina fine particles may be used to be added to the aqueous solution of the aggregation inhibitor as described above. An aqueous dispersion can be obtained by mixing the alumina fine particles and the anti-aggregation agent and then finely granulating the mixed solution using a disperser. As the disperser used to obtain the aqueous dispersion, various types of conventionally known ones such as a high-speed rotation disperser, a medium stirring type disperser (ball mill, sand mill, etc.), an ultrasonic disperser, a colloid mill disperser, a high-pressure disperser, etc. Although a disperser can be used, a colloid mill disperser or a high-pressure disperser is preferable from the viewpoint of efficiently dispersing the lump-shaped fine particles to be formed.

(Water-Soluble Resin) As the above-mentioned water-soluble resin,
For example, a resin having a hydroxyl group as a hydrophilic structural unit, polyvinyl alcohol (PVA), cation-modified polyvinyl alcohol, anion-modified polyvinyl alcohol, silanol-modified polyvinyl alcohol, polyvinyl acetal, cellulose resin [methyl cellulose (MC), ethyl cellulose ( EC), hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC), etc.], chitins, chitosans, starches; polyethylene oxide (PEO) and polypropylene oxide (PP) which are resins having an ether bond.
O), polyethylene glycol (PEG), polyvinyl ether (PVE); polyacrylamide (PAAM) which is a resin having an amide group or an amide bond, polyvinylpyrrolidone (PVP), and the like. Further, polyacrylic acid salts, maleic acid resins, alginates and gelatins having a carboxyl group as a dissociative group can be mentioned. Among the above, polyvinyl alcohols are particularly preferable.

The content of the water-soluble resin is preferably 9 to 40% by mass, more preferably 16 to 33% by mass, based on the total mass of the solid content of the colorant receiving layer. If the content is less than 9% by mass, the film strength may be lowered and cracks may easily occur during drying, and if it exceeds 40% by mass, the voids may be easily clogged with a resin, resulting in a void ratio. May decrease and the ink absorbency may decrease.

The alumina fine particles and the water-soluble resin, which mainly constitute the colorant receiving layer, may be a single material or a mixture of a plurality of materials.

From the viewpoint of transparency, the type of resin to be combined with the alumina fine particles is important. When the above-mentioned alumina fine particles are used, polyvinyl alcohol (PVA) is preferable as the water-soluble resin, and among them, the saponification degree is 7
0 to 99% PVA is more preferable, and saponification degree is 70 to 9
0% PVA is especially preferred.

The PVA has a hydroxyl group in its structural unit, and this hydroxyl group and the surface of the alumina fine particles form a hydrogen bond to easily form a three-dimensional network structure having secondary particles of the alumina fine particles as a chain unit. To do. It is considered that the formation of the above-mentioned three-dimensional network structure makes it possible to form a coloring material receiving layer having a porous structure with a high porosity. In inkjet recording, the porous coloring material-receiving layer obtained as described above can rapidly absorb ink by a capillary phenomenon and form dots with good circularity without ink blurring.

-Content Ratio of Alumina Fine Particles to Water-Soluble Resin-Content ratio of alumina fine particles (i) to water-soluble resin (p) [PB ratio (i: p), alumina fine particles to 1 part by mass of water-soluble resin] Mass] also has a great influence on the film structure of the colorant receiving layer. That is, as the PB ratio increases, the porosity,
Pore volume and surface area (per unit mass) increase. Specifically, the PB ratio (i: p) is 2: 1 to 1
0: 1 is preferred. If the PB ratio exceeds 10: 1, that is, if the PB ratio becomes too large, the film strength may decrease and cracks may easily occur during drying. If it is less than 2: 1 or the PB ratio is too small, As a result of the voids being easily clogged with the resin, the void ratio may decrease, and the ink absorbency may decrease.

For example, alumina fine particles having an average primary particle diameter of 20 nm or less and a water-soluble resin are used in a PB ratio of 2: 1 to 10 :.
When the coating liquid completely dispersed in an aqueous solution in 1 was coated on a support and the coating layer was dried, a three-dimensional network structure having secondary particles of alumina fine particles as chain units was formed, and the average pore diameter was It is possible to easily form a translucent porous film having a thickness of 30 nm or less, a porosity of 50% to 80%, a pore specific volume of 0.5 ml / g or more and a specific surface area of 100 m ² / g or more.

(Crosslinking Agent) The coloring material receiving layer of the ink jet recording sheet of the present invention comprises a coating layer (porous layer) containing alumina fine particles and a water-soluble resin, and a crosslinking agent capable of further crosslinking the water-soluble resin. It is preferable that the layer contains and is cured by a crosslinking reaction between the crosslinking agent and the water-soluble resin.

The application of the cross-linking agent is carried out at the same time as the coating liquid for forming the above-mentioned porous coloring material receiving layer (coloring material receiving layer coating liquid) is applied or the coating liquid for coloring material receiving layer is applied. It is preferable that the coating layer formed by applying the cross-linking agent-containing solution (cross-linking agent solution) is applied before the coating layer shows a decreasing rate of drying. Alternatively, the coating layer may be dried to form a coating film. By this operation, it is possible to effectively prevent the occurrence of cracks that occur during the drying of the coating layer. That is, the cross-linking agent solution penetrates into the coating layer at the same time as the coating liquid for the color material receiving layer is applied, or before the coating layer starts to exhibit a decreasing rate of drying, thereby forming a water-soluble resin in the coating layer. Reacts promptly,
By gelling (curing) the water-soluble resin, the film strength of the coating layer can be greatly improved immediately.

As the cross-linking agent capable of cross-linking the above-mentioned water-soluble resin, a suitable one may be appropriately selected in relation to the water-soluble resin used in the colorant receiving layer, but among them, the cross-linking reaction is rapid. Therefore, the boron compound is preferable. Examples of the boron compound include borax, boric acid, borate (eg orthoborate, InBO ₃ , ScBO ₃ , YBO ₃ , LaB).
O ₃ , Mg ₃ (BO ₃ ) ₂ , Co ₃ (BO ₃ ) ₂ , diborate (for example, Mg ₂ B ₂ O ₅ , Co ₂ B ₂ O ₅ ), metaborate (for example, LiBO ₂ , Ca) (BO ₂ ) ₂ , NaBO ₂ , K
BO ₂ ), tetraborate (for example, Na ₂ B ₄ O ₇ · 10H
₂ O), pentaborate (eg KB ₅ O ₈ .4H ₂ O, Ca _{2
B 6 O 11 · 7H 2 O} , CsB 5 O 5) can be mentioned. Other examples of the cross-linking agent include glyoxal, melamine / formaldehyde (eg, methylol melamine, alkylated methylol melamine), methylol urea, resole resin, polyisocyanate, epoxy resin and the like. Of these, boron compounds such as borax, boric acid, and borate are preferable, and boric acid is more preferable, because they rapidly cause a crosslinking reaction with polyvinyl alcohol.

When gelatin is used as the water-soluble resin, the following compounds known as a hardening agent for gelatin can be used as a crosslinking agent. 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.
Active halogen compounds such as 5-triazine and 2,4-dichloro-6-S-triazine sodium salt; divinyl sulfonic acid, 1,3-vinylsulfonyl-2-propanol, N, N'-ethylenebis (vinylsulfonyl acetate) Cetamide), active vinyl compounds such as 1,3,5-triacryloyl-hexahydro-S-triazine; N-methylol compounds such as dimethylolurea and methyloldimethylhydantoin;

Isocyanate compounds such as 1,6-hexamethylene diisocyanate; US Pat. No. 301
Nos. 7280 and 2983611; aziridine compounds; carboximide compounds described in U.S. Pat. No. 3,100,704; epoxy compounds such as glycerol triglycidyl ether; 1,6-hexamethylene-N, N '. -Ethyleneimino compounds such as bisethyleneurea; halogenated carboxaldehyde compounds such as mucochloric acid and mucophenoxycyclo acid; dioxane compounds such as 2,3-dihydroxydioxane; chromium alum, potassium alum, zirconium sulfate, Chromium acetate and the like. The cross-linking agents may be used alone or in combination of two or more.

The above crosslinking agent solution is prepared by dissolving the crosslinking agent in water and / or an organic solvent. The concentration of the cross-linking agent in the cross-linking agent solution is 0.
05-10 mass% is preferable and 0.1-7 mass% is especially preferable. Water is generally used as the solvent constituting the crosslinking agent solution, and may be an aqueous mixed solvent containing an organic solvent miscible with the water. Any organic solvent can be used as long as it can dissolve the crosslinking agent, and examples thereof include alcohols such as methanol, ethanol, isopropyl alcohol, and glycerin; ketones such as acetone and methyl ethyl ketone; methyl acetate, ethyl acetate, and the like. And the like; aromatic solvents such as toluene; ethers such as tetrahydrofuran; and halogenated carbon solvents such as dichloromethane.

(Organic mordant) In the present invention, the cationic polymer used as the aggregation preventing agent also exhibits the effect as a mordant, but in order to further improve the water resistance of the formed image and the bleeding resistance with time, a coloring material is used. It is preferable to further use an organic mordant (hereinafter, may be simply referred to as “mordant”) in the receptor layer. As the mordant, a cationic polymer (cationic mordant) is preferable, and by allowing the mordant to be present in the colorant-receiving layer, the colorant interacts with a liquid ink having an anionic dye as the colorant. It is possible to stabilize and improve water resistance and blurring over time.

However, when the cationic polymer is directly added to the coating material for the colorant-receiving layer for forming the colorant-receiving layer, there is a fear that it may aggregate with the alumina fine particles having a cationic charge depending on the type. If a method of preparing and applying as an independent separate solution is used, there is no need to worry about agglomeration of alumina fine particles. Therefore, in the present invention, when the organic mordant is used, it is preferably contained in a solution different from the above-mentioned alumina fine particles and used.

As the cationic mordant, a polymer mordant having a primary to tertiary amino group or a quaternary ammonium group as a cationic group is preferably used, but a cationic non-polymer mordant is also used. can do. As the polymer mordant, first to third
A homopolymer of a monomer (mordant monomer) having a primary amino group and a salt thereof, or a quaternary ammonium salt group, and a copolymerization weight of the mordant monomer and another monomer (hereinafter, referred to as "non-mordant monomer"). Those obtained as a polymer or a condensation polymer are preferable. Further, these polymer mordants can be used in the form of either a water-soluble polymer or water-dispersible latex particles.

Examples of the above-mentioned monomer (mordanting monomer) include trimethyl-p-vinylbenzylammonium chloride, trimethyl-m-vinylbenzylammonium chloride, triethyl-p-vinylbenzylammonium chloride, triethyl-m-vinylbenzylammonium. Chloride, N, N-dimethyl-N-ethyl-N-p-vinylbenzylammonium chloride,
N, N-diethyl-N-methyl-N-p-vinylbenzylammonium chloride, N, N-dimethyl-Nn
-Propyl-N-p-vinylbenzyl ammonium chloride, N, N-dimethyl-Nn-octyl-N-p
-Vinylbenzylammonium chloride, N, N-dimethyl-N-benzyl-Np-vinylbenzylammonium chloride, N, N-diethyl-N-benzyl-
N-p-vinylbenzylammonium chloride, N,
N-dimethyl-N- (4-methyl) benzyl-Np-
Vinylbenzylammonium chloride, N, N-dimethyl-N-phenyl-Np-vinylbenzylammonium chloride,

Trimethyl-p-vinylbenzylammonium bromide, trimethyl-m-vinylbenzylammonium bromide, trimethyl-p-vinylbenzylammonium sulfonate, trimethyl-m-vinylbenzylammonium sulfonate, trimethyl-p-vinylbenzylammonium acetate, trimethyl- m
-Vinylbenzyl ammonium 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 acetate,

N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth)
Acrylate, N, N-diethylaminopropyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylamide, N, N-diethylaminoethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N, Methyl chloride of N-diethylaminopropyl (meth) acrylamide,
Examples thereof include ethyl chloride, methyl bromide, ethyl bromide, quaternary compounds of methyl iodide or ethyl iodide, and sulfonates, alkylsulfonates, acetates or alkylcarboxylates of which anions are substituted.

Specifically, for example, monomethyldiallylammonium 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- (methacryloyl) Amino) ethylammonium chloride, trimethyl-
2- (acryloylamino) ethylammonium chloride, triethyl-2- (acryloylamino) ethylammonium chloride, trimethyl-3- (methacryloylamino) propylammonium chloride, triethyl-3- (methacryloylamino) propylammonium chloride, trimethyl-3- (Acryloylamino) propyl ammonium 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- (acryloylamino) propyl ammonium acetate etc. can be mentioned. In addition, examples of copolymerizable monomers include N-vinylimidazole and N-vinyl-2-methylimidazole.

The non-mordanting monomer does not contain a basic or cationic moiety such as a primary to tertiary amino group and its salt, or a quaternary ammonium salt group, and interacts with the dye in the ink jet ink. A monomer that does not show or has a substantially small interaction. Examples of the non-mordanting monomer include (meth) acrylic acid alkyl ester; (meth) acrylic acid cycloalkyl ester such as cyclohexyl (meth) acrylate; (meth)
(Meth) acrylic acid aryl ester such as phenyl acrylate; aralkyl ester such as benzyl (meth) acrylate; aromatic vinyls such as styrene, vinyltoluene, α-methylstyrene; vinyl acetate, vinyl propionate, vinyl versatate And vinyl 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.

The above-mentioned (meth) acrylic acid alkyl ester has a carbon number of 1 to 18 at the alkyl moiety.
Acrylic acid alkyl esters are preferable, for example, methyl (meth) acrylate, ethyl (meth) acrylate,
Propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate,
Examples include hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, and stearyl (meth) acrylate. Among them, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate and hydroxyethyl methacrylate are preferable. The non-mordant monomers can be used alone or in combination of two or more.

Further, as a polymer mordant, polydiallyldimethylammonium chloride, polymethacryloyloxyethyl-β-hydroxyethyldimethylammonium chloride, polyethylenimine, polyallylamine and its modified products, polyallylamine hydrochloride, polyamide-polyamine resin, cation Preferred examples include modified starch, dicyandiamide formalin condensate, dimethyl-2-hydroxypropylammonium salt polymer, polyamidine, and polyvinylamine.
Polyallylamine and its derivatives are particularly preferred.

The polyallylamine derivative is prepared by adding acrylonitrile, chloromethylstyrene, TEMPO, epoxyhexane, sorbic acid, etc. to polyallylamine in an amount of 2-5.
0 mol% added, preferably 5 to 10 mol% of acrylonitrile and chloromethylstyrene, particularly 5 to 10 mol% of polyallylamine.
Acrylonitrile adducts are preferable from the viewpoint of exerting the effect of preventing ozone fading.

The molecular weight of the mordant is the weight average molecular weight.
The preferable amount is 5000 to 200000. The above molecular weight
Is in the range of 5,000 to 200,000, the water resistance and
And resistance to bleeding over time can be improved. Also color material
The content of the cationic polymer in the receiving layer is 0.2
~ 1.5g / m²Is preferred, and 0.25 to 1 g / m²Changed
Is preferred. The content is 0.2 g / m ²Less than
The stain may worsen, 1.5 g / m²Exceeds
Ink absorbability may deteriorate.

(Other Components) The colorant receiving layer may contain the following components, if necessary. For the purpose of suppressing the deterioration of the coloring material, various kinds of ultraviolet absorbers, antioxidants, and fading inhibitors such as singlet oxygen quencher may be contained. Examples of the ultraviolet absorber include cinnamic acid derivatives, benzophenone derivatives, benzotriazolylphenol derivatives and the like. For example, α-cyano-phenyl butyl cinnamate, o
-Benzotriazole phenol, o-benzotriazole-p-chlorophenol, o-benzotriazole-2,4-di-t-butylphenol, o-benzotriazole-2,4-di-t-octylphenol and the like can be mentioned. A hindered phenol compound can also be used as an ultraviolet absorber, and specifically, a phenol derivative in which at least one of 2-position or 6-position is substituted with a branched alkyl group is preferable.

Further, benzotriazole type ultraviolet absorbers, salicylic acid type ultraviolet absorbers, cyanoacrylate type ultraviolet absorbers, oxalic acid anilide type ultraviolet absorbers and the like can also be used. For example, JP-A-47-1053
No. 7, gazette 58-111942 gazette, gazette 58-21.
No. 2844, No. 59-19945, No. 59-
46646, 59-109055, and 6
No. 3-53544, Japanese Patent Publication No. 36-10466, No. 42-26187, No. 48-30492, No. 48-31255, No. 48-41572.
JP-A-48-54965 and JP-A-50-1072.
No. 6, gazettes, US Pat. Nos. 2,719,086, 3,707,375, 3,754,919, 4,220,711, etc. There is.

A fluorescent whitening agent can also be used as an ultraviolet absorber, and examples thereof include a coumarin-based fluorescent whitening agent. Specifically, JP-B-45-4699 and 54-53.
No. 24, etc.

Examples of the above-mentioned antioxidant include European Patent Nos. 223739, 309401, 309402, 310551, and 31.
No. 0552, No. 459416, German Published Patent No. 3435443, and Japanese Patent Laid-Open No. 54-48535.
No. 60-107384 and No. 60-107.
No. 383, No. 60-125470, No. 60-
No. 125471, No. 60-125472, No. 60-287485, No. 60-287486, No. 60-287487, and No. 60-28748.
8 gazette, the same 61-160287 gazette, the same 61-18.
5483, 61-211079 and 62.
No. 146678, No. 62-146680,
62-146679, 62-282885, 62-262047, 63-0511.
74, 63-89877, 63-88.
No. 380, No. 66-88381, No. 63-1.
No. 13536,

63-163351 and 63-2.
No. 03372, No. 63-224989, No. 6
No. 3-251282, No. 63-267594, No. 63-182484, Japanese Patent Laid-Open No. 1-2392.
82, JP-A-2-262654, and 2-7.
No. 1262, No. 3-121449, and No. 4-2.
No. 91685, No. 4-291684, No. 5-
No. 61166, No. 5-119449, No. 5-
No. 188687, No. 5-188686, No. 5
-110490 gazette, the same 5-1108437 gazette,
No. 5-170361, Japanese Patent Publication No. 48-43295, No. 48-33212, and U.S. Pat. No. 4,814.
No. 262, No. 4980275, etc. are mentioned.

Specifically, 6-ethoxy-1-phenyl-2,2,4-trimethyl-1,2-dihydroquinoline, 6-ethoxy-1-octyl-2,2,4-trimethyl-1,2 -Dihydroquinoline, 6-ethoxy-1-
Phenyl-2,2,4-trimethyl-1,2,3,4-
Tetrahydroquinoline, 6-ethoxy-1-octyl-
2,2,4-trimethyl-1,2,3,4-tetrahydroquinoline, nickel cyclohexanoate, 2,2-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) -2 -Ethylhexane, 2
-Methyl-4-methoxy-diphenylamine, 1-methyl-2-phenylindole and the like can be mentioned.

The anti-fading agents may be used alone or in combination of two or more kinds. The anti-fading agent may be water-solubilized, dispersed, emulsified, or contained in microcapsules. The amount of the anti-fading agent added is preferably 0.01 to 10% by mass of the coating material for the colorant receiving layer.

Further, for the purpose of improving the dispersibility of the alumina fine particles, various inorganic salts and an acid or alkali as a pH adjusting agent may be contained. Further, metal oxide fine particles having electronic conductivity may be included for the purpose of suppressing frictional electrification and peeling electrification on the surface, and various matting agents may be included for the purpose of reducing the frictional property of the surface.

<Method for Forming Color Material Receiving Layer> Next, a method for forming the color material receiving layer will be described. The colorant receiving layer of the present invention,
A dispersion containing at least alumina fine particles dispersed in a cationic polymer and a water-soluble resin may be formed as a single solution using only a coating solution containing a cross-linking agent if necessary. When used, it is preferably formed by the following method. The coloring material receiving layer is formed by applying a dispersion liquid obtained by dispersing at least the alumina fine particles in a cationic polymer and a coating liquid containing the water-soluble resin (coating liquid for the coloring material receiving layer), and (1) applying the coating liquid. At the same time, (2) while the coating layer formed by the coating is being dried,
The coating layer contains at least the above organic mordant and a cross-linking agent either before the coating layer shows a rate of reduction drying rate or (3) after the coating layer is dried to form a coating film. It is preferably formed by a so-called WOW method, which is formed by applying a solution (crosslinking agent solution) and curing and drying the coating layer.

As described above, the water resistance of the colorant-receiving layer can be improved by adding the organic mordant together with the crosslinking agent to the crosslinking agent solution and simultaneously coating. That is, when the above organic mordant is added to the coating solution for the colorant receiving layer, aggregation may occur in the presence of alumina fine particles having a cationic charge on the surface depending on the type of the organic mordant such as polyallylamine. If the method in which the solution and the coating liquid for the colorant receiving layer are prepared independently and applied individually, it is not necessary to consider the aggregation of alumina fine particles, and the selection range of the organic mordant is expanded.

In the present invention, a coating solution for a colorant receiving layer containing a dispersion obtained by dispersing fine alumina particles in a cationic polymer and a water-soluble resin (eg PVA) is, for example, as follows. Can be prepared. That is, alumina fine particles are added to water (for example, 10 to 20% by mass), and a cationic polymer used as a coagulation inhibitor is further added to the high-speed rotating wet colloid mill (for example,
Claremix (manufactured by M Technique Co., Ltd.) is used, for example, 10,000 rpm (preferably 5000-2).
After being dispersed for 20 minutes (preferably 10 to 30 minutes) under the condition of high-speed rotation of 0000 rpm), an aqueous polyvinyl alcohol solution (for example, so that the PVA has a mass of about ¼ of alumina fine particles) is added, and It can be prepared by performing the dispersion under the same rotation conditions as. The obtained coloring material-receiving layer coating liquid is a uniform sol,
By coating and forming this on a support by the following coating method, a porous coloring material-receptive layer having a three-dimensional network structure can be formed. The coating liquid for the color material receiving layer,
If necessary, a surfactant, a pH adjusting agent, an antistatic agent, etc. can be further added.

The coating liquid for the color material receiving layer is applied, for example, by an extrusion die coater, an air doctor coater, a bread coater, a rod coater, a knife coater,
It can be performed by a known coating method such as a squeeze coater, a reverse roll coater, or a bar coater.

The above-mentioned "before the coating layer shows the rate of decrease in drying rate" usually means a few minutes immediately after the coating liquid for the color material-receptive layer is applied, and during this period, the applied coating is performed. The constant drying rate, which is a phenomenon in which the content of the solvent in the layer decreases in proportion to time, is shown. The time indicating the constant rate of drying is described in Chemical Engineering Handbook (p. 707 to 712, published by Maruzen Co., Ltd., October 25, 1980).

As described above, the coating layer is dried after being coated with the coating solution for the color material-receptive layer until it shows a decreasing rate of drying. The drying is generally performed at 50 to 180 ° C. for 0.5 times.
It is performed for 10 minutes (preferably 0.5 to 5 minutes). As the drying time, it naturally depends on the coating amount, but the above range is suitable.

As a method for applying the organic mordant and the cross-linking agent before the above-mentioned coating layer shows the rate of decrease in drying rate, (1) a method of further coating the cross-linking agent solution on the coating layer, (2) ) A method of spraying the crosslinking agent solution by a method such as spraying, and (3) a method of immersing the support on which the coating layer is formed in the solution of the crosslinking agent solution.

In the above method (1), as a coating method for coating the crosslinking agent solution, for example, a curtain flow coater, an extrusion die coater, an air doctor coater, a bread coater, a rod coater, a knife coater, a squeeze coater, a reverse roll coater, A known coating method such as a bar coater can be used. However, it is preferable to use a method such as an extrusion die coater, a curtain flow coater, or a bar coater in which the coater does not directly contact the already-formed coating layer. Further, in these coatings, two or more kinds of coating liquids may be simultaneously coated in a multilayer manner.

The simultaneous coating (multilayer coating) can be carried out by a coating method using 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 at 40 to 150 ° C. for 0.5 to 1
Heating for 0 minutes, preferably
It is carried out by heating at 40 to 100 ° C. for 0.5 to 5 minutes. For example, when borax or boric acid is used as the cross-linking agent contained in the cross-linking agent solution, it is preferable to heat at 60 to 100 ° C for 5 to 20 minutes.

When the cross-linking agent solution is applied after the coating layer is dried to form a coating film, the coating layer is dried at 40
It is carried out by heating at ~ 150 ° C for 0.5 to 10 minutes, preferably at 40 to 100 ° C for 0.5 to 5 minutes.

In each step of the above-mentioned coating, water, an organic solvent, or a mixed solvent thereof can be used as a solvent. 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, toluene and the like. To be

After the color material receiving layer is formed on the support, the surface of the color material receiving layer is smoothed by subjecting the color material receiving layer to calendering under heat and pressure through a roll nip using, for example, a super calender or a gloss calender. Sex, glossiness,
It is possible to improve transparency and coating film strength.
However, the calendering process may cause a decrease in the porosity (that is, the ink absorbency may decrease), so it is necessary to set conditions under which the decrease in the porosity is small.

The roll temperature for calendering treatment is preferably 30 to 150 ° C., and 40 to 100 ° C.
C is even more preferred. The linear pressure between the rolls during the calendering treatment is preferably 50 to 400 kg / cm, more preferably 100 to 200 kg / cm.

In the case of an ink jet recording sheet, the layer thickness of the color material receiving layer needs to be determined in relation to the porosity in the layer, since it is necessary to have an absorption capacity enough to absorb all the droplets. There is. For example, if the ink amount is 8 nL / mm
² and the porosity is 60%, the layer thickness is about 15μ.
A film having a thickness of m or more is required. Considering this point, in the case of inkjet recording, the layer thickness of the colorant receiving layer is
10 to 50 μm is preferable.

The pore diameter of the colorant receiving layer is preferably 0.005 to 0.030 μm in terms of median diameter, and 0.01 to 0.03 μm.
0.025 μm is more preferable. The porosity and the median pore diameter can be measured using a mercury porosimeter (trade name: Boasizer 9320-PC2, manufactured by Shimadzu Corporation).

The coloring material receiving layer preferably has excellent transparency. As a guideline, the haze value when the coloring material receiving layer is formed on a transparent film support is 30.
% Or less, and more preferably 20% or less. The haze value is a haze meter (H
GM-2DP: can be measured using Suga Test Instruments Co., Ltd.

<Support> As the support, any of a transparent support made of a transparent material such as plastic and an opaque support made of an opaque material such as paper can be used. In order to make the most of the transparency of the colorant receiving layer, it is preferable to use a transparent support or a highly glossy opaque support.

As a material that can be used for the above-mentioned transparent support, a material which is transparent and has the property of withstanding radiant heat when used in an OHP or backlight display is preferable. Examples of the material include polyesters such as polyethylene terephthalate (PET); polysulfone,
Examples thereof include polyphenylene oxide, polyimide, polycarbonate and polyamide. Among them, polyesters are preferable, and polyethylene terephthalate is particularly preferable. The thickness of the transparent support is not particularly limited, but is preferably 50 to 200 μm from the viewpoint of handleability.

As the highly glossy opaque support, one having a glossiness of 40% or more on the surface on which the colorant receiving layer is provided is preferable. The glossiness is JIS P-814.
It is a value determined according to the method described in 2 (75 degree specular gloss test method for paper and board). Specific examples include the following supports.

For example, high gloss paper support such as art paper, coated paper, cast coated paper, baryta paper used for silver salt photographic support, polyesters such as polyethylene terephthalate (PET), nitrocellulose. , Cellulose acetate, cellulose acetate such as cellulose acetate butyrate, plastic film such as polysulfone, polyphenylene oxide, polyimide, polycarbonate, polyamide, etc. were made opaque by containing a white pigment etc. (may be subjected to surface calendering treatment) High-gloss film; or a high-gloss film containing the above various paper supports, the above-mentioned transparent supports, or white pigments, etc., provided with a polyolefin coating layer containing or not containing a white pigment. Support. Further, a white pigment-containing expanded polyester film (for example, expanded PET in which polyolefin fine particles are contained and voids are formed by stretching) can also be preferably mentioned.

The thickness of the opaque support is not particularly limited, but is preferably 50 to 300 μm from the viewpoint of handleability.

Further, a corona discharge treatment,
Those subjected to glow discharge treatment, flame treatment, ultraviolet irradiation treatment and the like may be used.

Next, the base paper used for the paper support will be described in detail. The base paper is made from wood pulp as a main raw material, and if necessary, synthetic paper such as polypropylene, or synthetic fiber such as nylon or polyester is used in addition to wood pulp. As the wood pulp, LBKP, LBSP, NBKP, NBSP, LD
Any of P, NDP, LUKP and NUKP can be used, but LBKP, NBSP, LB with a large amount of short fibers
It is preferable to use more SP, NDP, and LDP. However, the ratio of LBSP and / or LDP is preferably 10% by mass or more and 70% by mass or less.

As the above-mentioned pulp, chemical pulp containing few impurities (sulfate pulp or sulfite pulp) is preferably used,
Pulp that has been bleached to improve its whiteness 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 strengthening agents such as starch, polyacrylamide and polyvinyl alcohol, fluorescent whitening agents, A water retention agent such as polyethylene glycol, a dispersant, and a softening agent such as quaternary ammonium can be appropriately added.

The freeness of the pulp used for papermaking is as follows.
According to CSF regulations, 200 to 500 ml is preferable, and
The fiber length after beating is preferably 30 to 70% of the sum of the 24 mesh residual mass% and the 42 mesh calculated mass% defined in JIS P-8207. The mass% of the 4-mesh residue is preferably 20 mass% or less.

The basis weight of the base paper is preferably 30 to 250 g, 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 papermaking stage or after the papermaking. The base paper density is 0.7 to 1.2 g / m ² (J
ISP-8118) is common. Furthermore, the stiffness of the base paper is 2 under the conditions specified in JIS P-8143.
0 to 200 g is preferable.

A surface sizing agent may be applied to the surface of the base paper, and as the surface sizing agent, the same sizing agent as that which can be added to the base paper can be used. The pH of the base paper is JI
It is preferably 5 to 9 when measured by the hot water extraction method specified in SP-8113.

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

In particular, the polyethylene layer on the side for forming the colorant receiving layer is formed by adding rutile or anatase type titanium oxide to polyethylene, as is commonly used in photographic printing paper, to obtain opacity and whiteness. Those improved are preferable. Here, the content of titanium oxide is preferably about 3 to 20 mass% with respect to polyethylene, and 4
-13 mass% is more preferable.

The polyethylene-coated paper can be used as a glossy paper, or when a polyethylene is melt-extruded on the surface of a base paper for coating, a so-called patterning treatment is performed to obtain a matte surface or a matte surface obtained by ordinary photographic printing paper. It is also possible to use those having a silk surface.

As described above, according to the present invention, it is possible to improve glossiness, ink absorption speed, bleeding resistance over time, and light resistance without deteriorating the performance of other inks. In addition, when the colorant receiving layer contains alumina fine particles and has a three-dimensional network structure with a porosity of 50 to 80%, good ink absorption is exhibited and a high-resolution image can be formed.
It is also possible to secure excellent ink receiving performance such that bleeding with time in a high-temperature and high-humidity environment is suppressed and the formed image also has high light resistance and water resistance.

[0106]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. still,
Unless otherwise specified, "parts" and "%" in the examples represent "parts by mass" and "mass%", the number following "WM" represents "weight average molecular weight", and the "degree of polymerization" is ""Weight average degree of polymerization".

[Example 1] -Preparation of support-Art paper (OK Kinfuji; manufactured by Oji Paper Co., Ltd.) having a weight of 186 g / m ² was subjected to corona discharge treatment, and then high density was obtained using a melt extruder. Polyethylene was coated to a thickness of 19 μm to form a resin layer composed of a matte surface (hereinafter, the resin layer surface is referred to as “rear surface”). The resin layer on the back surface side is further subjected to corona discharge treatment, and thereafter, aluminum oxide (alumina sol 10 is used as an antistatic agent).
0, Nissan Chemical Industries, Ltd.) and silicon dioxide (Snowtex O, Nissan Chemical Industries, Ltd.) were dispersed in water at a ratio of 1: 2 (mass ratio) to obtain a dry mass of 0. .2 g /
It was applied so as to be m ² .

Further, after the corona discharge treatment was applied to the felt surface (surface) side where the resin layer was not provided, anatase type titanium dioxide 10%, a trace amount of ultramarine blue, and an optical brightening agent 0.01% ( To polyethylene), MFR
(Melt flow rate) 3.8 low-density polyethylene was melt-extruded to a thickness of 24 μm using a melt extruder to form a high-gloss thermoplastic resin layer on the surface side of the base paper (hereinafter, This high-gloss surface is referred to as the "front surface"), and was used as a support. The front surface of the support was used after being subjected to corona discharge treatment before applying the coating liquid.

-Preparation of Coating Solution for Coloring Material Receiving Layer-Alumina fine particles are mixed with ion-exchanged water having the following composition,
The above compound (1) (cationic polymer used as an agglomeration inhibitor) is further mixed and treated with Nanomizer LA31 (manufactured by Nanomizer Co., Ltd.) twice at a pressure of 500 kg / m ² and then for 60 minutes. After stirring, an 8% aqueous solution of polyvinyl alcohol having the following composition was added with stirring, and Emulgen 109P (10
%) Aqueous solution and boric acid are added, and coating solution A for colorant receiving layer
Was prepared. The mass ratio of the alumina fine particles to the water-soluble resin was 3.5: 1.

[Composition of Coating Liquid A for Coloring Material Receiving Layer] Alumina fine particles 7.8 parts (specific surface area by BET method: 100 m ² / g, average primary particle diameter 10 nm, Aluminum Oxide C, manufactured by Nippon Aerosil Co., Ltd.) ) -Ion-exchanged water 61.4 parts-The above compound (1) 1.5 parts (cationic polymer used as an aggregation inhibitor, solid content concentration 30%, molecular weight 7000) -Polyvinyl alcohol 8% aqueous solution 21.3 parts (PVA124, Kuraray Co., Ltd., saponification degree 98.5%, degree of polymerization 2400) -Polyoxyethylene lauryl ether 1.0 part (nonionic surfactant; Emulgen 109P (10%), manufactured by Kao Corporation) -Boric acid 7.0 copies

—Preparation of Inkjet Recording Sheet— The obtained coating material A for colorant receiving layer is applied to the surface of a support,
After cooling once at about 7 ° C., it was dried by blowing a wind at 20 to 65 ° C. to prepare an inkjet recording sheet (1) of the present invention.

[Example 2] InkJet recording of the present invention was carried out in the same manner as in Example 1 except that the coating liquid A for the colorant receiving layer was changed to the coating liquid B for the colorant receiving layer having the following composition. A sheet (2) for use was prepared.

[Composition of Coating Liquid B for Coloring Material Receiving Layer] Alumina fine particles 7.8 parts (specific surface area by BET method: 100 m ² / g, average primary particle diameter 10 nm, Aluminum Oxide C, manufactured by Nippon Aerosil Co., Ltd.) ) -Ion-exchanged water 61.4 parts-The above compound (2) 1.5 parts (cationic polymer used as an anti-aggregation agent, solid content concentration 30%, molecular weight 10000) -Polyvinyl alcohol 8% aqueous solution 21.3 parts (PVA124, Kuraray Co., Ltd., saponification degree 98.5%, degree of polymerization 2400) -Polyoxyethylene lauryl ether 1.0 part (nonionic surfactant; Emulgen 109P (10%), manufactured by Kao Corporation) -Boric acid 7.0 copies

[Example 3] Inkjet recording of the present invention in the same manner as in Example 1 except that the coating liquid A for the colorant receiving layer was changed to the coating liquid C for the colorant receiving layer having the following composition. A sheet (3) was prepared.

[Composition of Coating Liquid C for Coloring Material Receiving Layer] Alumina fine particles 7.8 parts (specific surface area by BET method: 100 m ² / g, average primary particle diameter 10 nm, Aluminum Oxide C, manufactured by Nippon Aerosil Co., Ltd.) ) -Ion-exchanged water 62.1 parts-The above compound (3) 0.8 parts (cationic polymer used as an anti-aggregation agent, solid content concentration 60%, PAS-M-1, Nitobo Co., Ltd., molecular weight 20000) -Polyvinyl alcohol 8% aqueous solution 21.3 parts (PVA124, manufactured by Kuraray Co., saponification degree 98.5%, polymerization degree 2400) -Polyoxyethylene lauryl ether 1.0 part (nonionic surfactant; Emulgen 109P ( 10%), manufactured by Kao Corporation) -Boric acid 7.0 parts

[Example 4] InkJet recording of the present invention was carried out in the same manner as in Example 1 except that the coating liquid A for the colorant receiving layer was changed to the coating liquid D for the colorant receiving layer having the following composition. A sheet (4) for use was prepared.

[Composition of Coating Liquid D for Coloring Material Receiving Layer] Alumina fine particles 7.8 parts (specific surface area by BET method: 100 m ² / g, average primary particle diameter 10 nm, Aluminum Oxide C, manufactured by Nippon Aerosil Co., Ltd.) ) -Ion-exchanged water 62.1 parts-The above compound (4) 1.7 parts (cationic polymer used as an anti-agglomeration agent, solid content concentration 60%, PAS-H-5L, manufactured by Nittobo Co., Ltd., molecular weight 40,000) -Polyvinyl alcohol 8% aqueous solution 21.3 parts (PVA124, manufactured by Kuraray Co., saponification degree 98.5%, polymerization degree 2400) -Polyoxyethylene lauryl ether 1.0 part (nonionic surfactant; Emulgen 109P ( 10%), manufactured by Kao Corporation) -Boric acid 7.0 parts

[Example 5] -Preparation of coating liquid for colorant receiving layer-Alumina fine particles were mixed with ion-exchanged water having the following composition,
The above compound (3) (cationic polymer used as an agglomeration inhibitor) is further mixed and treated twice with Nanomizer LA31 (manufactured by Nanomizer Co., Ltd.) at a pressure of 500 kg / m ² , and then for 60 minutes. After stirring, an 8% aqueous solution of polyvinyl alcohol having the following composition was added with stirring, and Emulgen 109P (10
%) Aqueous solution was added to prepare coating solution E for colorant receiving layer.
The mass ratio of the alumina fine particles to the water-soluble resin is 3.5: 1.
Met.

[Composition of Coating Liquid E for Coloring Material Receiving Layer] Alumina fine particles 7.8 parts (specific surface area by BET method: 100 m ² / g, average primary particle diameter 10 nm, Aluminum Oxide C, manufactured by Nippon Aerosil Co., Ltd.) ) -Ion-exchanged water 62.1 parts-The above compound (3) 0.8 parts (cationic polymer used as an anti-aggregation agent, solid content concentration 60%, PAS-M-1, Nitobo Co., Ltd., molecular weight 20000) -Polyvinyl alcohol 8% aqueous solution 21.3 parts (PVA124, manufactured by Kuraray Co., saponification degree 98.5%, polymerization degree 2400) -Polyoxyethylene lauryl ether 1.0 part (nonionic surfactant; Emulgen 109P ( 10%), manufactured by Kao Corporation)

—Preparation of Inkjet Recording Sheet— The colorant-receptive layer coating liquid E obtained above was applied to the front side of the support using an extrusion die coater.
A coating amount of 0 ml / m ² was applied (coating step), followed by drying with a hot air dryer at 80 ° C. (air velocity 3 to 8 m / sec) until the solid concentration of the coating layer reached 20%. The coating layer showed a constant drying rate during this period. Immediately after that, it was immersed in a cross-linking agent solution A having the following composition for 30 seconds, and 20 g / m
² is attached (step of applying a cross-linking agent solution), and further 80
It was dried at 0 ° C. for 10 minutes (drying step). From this, an inkjet recording sheet (5) of the present invention provided with a coloring material receiving layer having a dry film thickness of 32 μm was produced.

[0121] [Composition of Crosslinking Agent Solution A] ・ Boric acid (crosslinking agent) 1.5 parts ・ Ion-exchanged water 76.5 parts ・ 25% ammonia water 94.5 parts ・ Polyoxyethylene lauryl ether (nonionic surfactant) 2 parts (Emulgen 109P (10%), manufactured by Kao Corporation)

Example 6 An ink jet recording sheet (6) of the present invention was used in the same manner as in Example 5 except that the crosslinking agent solution A was changed to the crosslinking agent solution B having the following composition.
Was produced.

[0123] [Composition of Crosslinking Agent Solution B] ・ Boric acid (crosslinking agent) 1.5 parts ・ Ion-exchanged water 76.5 parts ・ Polyallylamine (10%) aqueous solution (WM10000) 20 parts ・ Polyoxyethylene lauryl ether (nonionic surfactant) 2 parts (Emulgen 109P (10%), manufactured by Kao Corporation)

Comparative Example 1 A comparative ink jet recording sheet was prepared in the same manner as in Example 1 except that the coating material A for coloring material receiving layer in Example 1 was changed to the coating fluid F for coloring material receiving layer having the following composition. Was produced.

[Composition of Coating Liquid F for Coloring Material Receiving Layer] Alumina fine particles 7.8 parts (specific surface area by BET method: 100 m ² / g, average primary particle diameter 10 nm, Aluminum Oxide C, manufactured by Nippon Aerosil Co., Ltd.) ) -Ion-exchanged water 62.9 parts-Polyvinyl alcohol 8% aqueous solution 21.3 parts (PVA124, manufactured by Kuraray Co., Ltd., saponification degree 98.5%, polymerization degree 2400) -Polyoxyethylene lauryl ether 1.0 part ( Nonionic surfactant; Emulgen 109P (10%), manufactured by Kao Corporation) ・ Boric acid 7.0 parts

-Evaluation Method- (1-1) Glossiness The 60 ° glossiness on the surface of the color material receiving layer of the recording sheet before printing was measured by a digital variable angle glossmeter (UGV-50DP, manufactured by Suga Test Instruments Co., Ltd.). ). The results are shown in Table 1.

(1-2) Ink Absorption Rate Using an ink jet printer (PM-900C, manufactured by Seiko Epson Corporation), Y (yellow), M (magenta), C (cyan), K
Solid images of (black), B (blue), G (green) and R (red) are printed, and immediately (after about 10 seconds), the paper is contact-pressed on the image to transfer the ink to the paper. The presence or absence of each of these was evaluated according to the following criteria. The results are shown in Table 1. [Standard] AA: Ink transfer onto paper was not observed at all. It shows that the ink absorption rate is good. CC: Partial transfer of the ink onto the paper was observed.

(1-3) Blurring with Time Using the same printer as in (1-2) above, a grid-like linear pattern (line width 0. Two
8 mm) was printed, and the visual density was measured by X-light 310TR (manufactured by X-light). Furthermore, after printing for 3 hours, the product was stored in a thermo-hygrostat at 40 ° C. and a relative humidity of 90% for 1 day, and the visual density was measured again to calculate the density difference (ΔOD). The smaller the value of the density difference (ΔOD), the more the generation of bleeding with time is suppressed. The results are shown in Table 1.

(1-4) Lightfastness Using the same printer as in (1-2) above, solid Y (yellow), M (magenta), C (cyan) and K (black) inks are formed on an ink jet recording sheet. Print the image, X light 3
The visual density of each color was measured by 10TR (manufactured by X-Light Co., Ltd.). After that, 365n for the printed image
Xenon weather-ometer Ci through a film that blocks ultraviolet rays in the wavelength range of m or less
Using 65A (manufactured by ATLAS), the lamp was lit for 3.8 hours under the environmental conditions of 25 ° C. and relative humidity of 32%, and then the lamp was extinguished at 20 ° C. and relative humidity of 91%. A cycle of standing for 1 hour underneath was carried out for 7 days. Then, the visual density of each color was measured again, and the residual rate of magenta having a low residual rate (rate of change in density before and after the test) in each color was calculated. The results are shown in Table 1.

(1-5) Image Density (Printing Density) Using the same printer as in (1-2) above, a solid K (black) image is printed on an ink jet recording sheet and left for 3 hours before printing. The reflection density of the surface was measured with a Macbeth reflection densitometer. The results are shown in Table 1.

[0131]

[Table 1]

From Table 1 above, in Examples 1 to 6 in which the alumina fine particles are dispersed in the cationic polymer, the glossiness, ink absorbency, bleeding with time, light fastness and image density (printing density) are obtained without aggregation of the coating liquid. Was good in all. Particularly, in Example 6 in which the colorant receiving layer was formed by the WOW method and the organic mordant was used, the glossiness was high. On the other hand, in Comparative Example 1 in which the alumina fine particles were used but the cationic polymer was not used for dispersion, the glossiness, the ink absorbability, and the blurring with time were particularly poor.

[0133]

INDUSTRIAL APPLICABILITY The present invention has good ink absorbency without lowering other ink receiving performance, has a high print density of an image, is excellent in gloss feeling and bleeding resistance with time, and is capable of receiving sunlight, fluorescent lamps, etc. It is possible to provide an inkjet recording sheet that exhibits high light resistance even under the irradiation of light. In addition, the present invention can provide an ink jet recording sheet that is strong without cracks and the like, forms a high resolution image, and is excellent in water resistance.

Claims (6)

[Claims] 1. An inkjet recording sheet having a colorant receiving layer on the surface of a support, wherein the colorant receiving layer comprises
An inkjet recording sheet, which is formed by using a coating liquid containing a dispersion liquid obtained by dispersing alumina fine particles in a cationic polymer and a water-soluble resin. 2. The ink jet recording sheet according to claim 1, wherein the color material receiving layer contains a crosslinking agent capable of crosslinking the water-soluble resin. 3. The ink jet recording sheet according to claim 1, wherein the alumina fine particles have an average primary particle diameter of 5 to 100 nm. 4. The coloring material receiving layer is formed by applying a coating liquid containing a water-soluble resin and a dispersion liquid obtained by dispersing the alumina fine particles in a cationic polymer on the surface of the support,
(1) Simultaneously with the coating, (2) during the drying of the coating layer formed by the coating and before the coating layer shows a decreasing rate of drying, and (3) drying the coating layer to form a coating film. The ink jet recording sheet according to claim 2 or 3, which is obtained by applying a solution containing the cross-linking agent and an organic mordant to at least one of the following after forming. 5. The inkjet recording sheet according to claim 2, wherein the crosslinking agent is a boron compound. 6. The ink jet recording sheet according to claim 4 or 5, wherein the organic mordant is polyallylamine or a derivative thereof.