JP2001341412A - Ink jet recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording body which is excellent in light fastness and can record an ink image having high color density, uniformity and bleeding resistance. SOLUTION: At least the outermost layer of an ink receiving layer formed on a base material contains a binder and fine pigment particles having an average particle diameter of 1 μm or less, and at least one layer of the ink receiving layer contains a phenol compound and a boron compound. An image lightfastness enhancer comprising at least one of an acid, a borate and a cyclodextrin is contained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink-jet recording material, and more particularly to an ink-jet recording material which is excellent in ink-jet recording suitability, has remarkably improved light resistance of a printed portion, and has excellent gloss.

[0002]

2. Description of the Related Art An ink jet recording system in which an aqueous ink is ejected from a fine nozzle toward a recording medium to form an image on the surface of the recording medium has low noise at the time of recording, easy full-color printing, and high-speed recording. It is widely used in terminal printers, facsimile machines, plotters, form printing, and the like because of the fact that printing is possible and the recording cost is lower than other printing apparatuses. On the other hand, with the rapid spread of printers, high definition and high speed, and the advent of digital cameras, advanced characteristics have been demanded on the recording medium side. That is, there is a strong demand for a recording medium that is excellent in absorbency, recording density, water resistance, and light resistance and that has both image quality and storability comparable to silver halide type photographs. Further, in order to make the recording product more photo-like, high glossiness is also required.

[0003] Generally, as a method of imparting glossiness,
There is known a method of smoothing the surface of a coating layer by passing a recording medium between rolls to which pressure or temperature is applied by using a device such as a super calender. However, in such a method, the obtained gloss is insufficient, and the ink-absorbing voids distributed in the coating layer are reduced. I will.

In addition, an ink receiving material containing an ink-absorbing resin such as starch, gelatin, a water-soluble cellulose derivative, polyvinyl alcohol and polyvinyl pyrrolidone on a support made of a glossy and smooth plastic film or resin-coated paper. Many methods of providing layers have been proposed. Although the recording medium having such a configuration shows high glossiness, ink absorption and drying are slow, so that handling properties are poor, and ink absorption unevenness is likely to occur,
Furthermore, there was a problem that the water resistance and the curl resistance were also poor.

As a means for solving these problems, a coating film containing an ultrafine pigment as a main component has been proposed as an ink receiving layer (JP-A-8-67064, JP-A-8-118790). JP-A-9-286
162, JP-A-10-217601, etc.).
Among these proposals, methods using colloidal silica having a small particle size (JP-A-8-67064, JP-A-8-67064)
JP-A-118790) is effective for obtaining a certain degree of gloss and water resistance, but since colloidal silica is primary particles, there is a sufficient space between the primary particles for effective ink absorption. Was not formed, and the ink absorbency was still not satisfactory.

As a paper having a high surface gloss, there is known a so-called cast coated paper obtained by a method in which a wet coating layer is pressed against a heated drum surface having a mirror surface and dried to copy the mirror surface. This cast coated paper has higher surface gloss and better surface smoothness than super calendered normal coated paper, and excellent printing effect is obtained. It is used exclusively for such purposes. However, when this cast coated paper is used as an ink jet recording medium, various difficulties arise.

That is, in general, in a conventional cast coated paper, a film-forming substance such as an adhesive contained in a pigment composition constituting the coated layer transfers a high gloss by copying a mirror drum surface of a cast coater. Expresses sex. On the other hand,
The presence of the film-forming substance causes a problem that the porosity of the coating layer is lost, and the ink absorbency at the time of inkjet recording is extremely reduced. In order to improve the ink absorbency, it is important to form a porous structure in the cast coating layer so that the ink can be easily absorbed, and for that purpose, it is necessary to lower the film formability. However, reducing the content of the film-forming substance causes a problem that the resulting recording layer has reduced white paper gloss. As described above, it has been extremely difficult to maintain both the surface gloss and the inkjet recording suitability of the cast coated paper at a satisfactory level at the same time.

As a method for solving the above problem, 40 base paper having a recording layer mainly composed of a pigment and an adhesive is provided.
A coating liquid containing a copolymer composition having a glass transition point of not less than ° C. as a main component is applied to form a coating layer for casting, and heating is performed while the coating layer for casting is in a wet state. Japanese Patent Application Laid-Open No. H07-197204 discloses that a cast paper for ink jet recording having excellent gloss and ink absorbency can be obtained by pressing and contacting the mirror surface drum and drying and finishing.
89220. Further, Japanese Unexamined Patent Application Publication No.
JP-A-274587 and JP-A-10-250218 propose that ultrafine inorganic colloid particles are mixed in a cast coating layer.

[0009] However, in recent years, with the increasing use of inkjet recording at higher speeds, higher definition of recorded images, and full-color printing, higher quality, higher recording density, and higher storability have been demanded for recording media. Recording quality that is comparable to, for example, silver halide photographic paper,
Preservability is required. The technology proposed above is not yet sufficient to satisfy such demands. In particular, even in the case of the above-described ink-jet paper excellent in gloss and ink-jet recording suitability, sunlight, room light (fluorescent light, etc.)
The problem of fading of the printed portion when exposed to water has not been solved yet.

Many techniques have been proposed for adding light-fastness to ink-jet recording paper by incorporating various materials. For example, Japanese Patent Application Laid-Open No. 57-87988 discloses an ink jet recording sheet characterized by containing an ultraviolet absorbent as at least one component.
Japanese Patent No. 46591 discloses an inkjet recording medium for forming a recorded image using an aqueous ink containing a water-soluble dye, wherein the recording medium contains a hindered amine compound. Japanese Patent Application Laid-Open No. Hei 4-201594 discloses that in a recording material having a base material and an ink receiving layer provided on the base material, the ink receiving layer contains an ultrafine powder of a transition metal compound. A recording material characterized by the following is disclosed. In these recording media, a tentative effect of improving light fastness is obtained, but there is a problem that the ink absorbency is insufficient, and the light fastness also impairs the color balance after fading.

JP-A-1-241487 discloses that a compound having a phenolic hydroxyl group of 0.1 to 30 as a light fastness improving additive is added to 100 parts by weight of a resin binder comprising polyvinyl alcohol and a cationic water-soluble resin.
Although a water-based ink recording target material formed by providing a coating in which parts by weight are blended on the surface of a substrate sheet has been disclosed,
The effect of improving light resistance was insufficient. Also, Japanese Patent Application Laid-Open
JP-132727 discloses an ink receiving layer containing a metal complex of polyvinyl alcohol and calcium chloride, and JP-A-9-290556 discloses a sulfuric acid having a dry adhesion amount of 0.2 to 2.0 g / m ² . There is disclosed an ink jet recording sheet in which magnesium is adhered to a support. These recording materials had relatively good color balance after fading, but lacked the residual ratio of color density of the image, and were not at a practical level.

Japanese Patent Application Laid-Open No. Hei 10-193776 discloses an ink jet recording material characterized by containing one kind selected from an image stabilizer and an ultraviolet absorber as a fading inhibitor. However, some anti-fading agents have a tendency to lower the ink absorption, and the light resistance is not sufficient. JP-A-11-2
JP-A No. 0306 and JP-A-11-192777 disclose an ink jet recording paper in which boric acid or borax is contained as a cross-linking agent in an ink receiving layer in order to improve water resistance. Gender compatibility was not enough. JP-A-2000-73296
Japanese Patent Application Laid-Open Publication No. H11-176,086 discloses a paper in which the change in shape (curl state) with respect to environmental changes is reduced by incorporating borax in the porous layer, but it is not sufficient to obtain gloss. JP-A-11-263065 discloses a mat type ink jet recording sheet which contains a cyclodextrin in an ink receiving layer and is excellent in dot reproducibility, resolution, color reproducibility, color development and pigment ink suitability. Kaihei 11-2
Japanese Patent No. 86172 discloses that a recording sheet containing a cyclodextrin in an ink receiving layer improves light resistance, but the gloss of these recording sheets is not sufficient.

[0013]

SUMMARY OF THE INVENTION The present invention provides a print density,
An object of the present invention is to provide an ink jet recording body which is excellent in ink jet recording suitability such as recording image quality, has high image light resistance, and is excellent in glossiness.

[0014]

The ink jet recording medium (1) of the present invention comprises a base material and an ink receiving layer formed on at least one surface of the base material, wherein the ink receiving layer has a thickness of 1 μm. It contains fine pigment particles having the following average particle diameter and a binder, and contains an image lightfastness improver consisting of at least one selected from phenol compounds, boric acid, borates and cyclodextrin compounds. It is characterized by the following. The ink jet recording medium (2) of the present invention includes a base material, and a composite ink receiving layer formed on at least one surface of the base material and composed of a plurality of ink receiving layers stacked on each other. Of the ink receiving layers, the outermost ink receiving layer located on the outermost side,
An image containing fine pigment particles of 1 μm or less and a binder, wherein at least one of the plurality of ink-receiving layers is made of at least one selected from a phenol compound, boric acid, borate, and cyclodextrin; It is characterized by containing a performance improver. In the ink jet recording material (1) or (2) of the present invention, the fine pigment particles are composed of aggregates of a plurality of primary particles having an average primary particle size of 3 to 40 nm, and have an average secondary particle size of 1 μm or less. It is preferable to have the shape of a secondary particle having the following. Ink jet recording medium (1) or (2) of the present invention
In the above, the phenol compound is preferably selected from a hydroquinone compound, a pyrocatechol compound, and a phenolsulfonic acid compound. In the ink jet recording material (1) or (2) of the present invention, the cyclodextrin compound is α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, alkylated cyclodextrin, hydroxyalkylated cyclodextrin, and cation-modified cyclodextrin. It is preferably selected from dextrins. In the ink jet recording material (1) or (2) of the present invention, the cyclodextrin compound is preferably γ-cyclodextrin. In the ink jet recording medium (1) or (2) of the present invention, the image lightfastness improver is contained in the ink receiving layer by applying a solution thereof on the ink receiving layer and drying the solution. Is preferred. In the ink jet recording medium (1) or (2) of the present invention, the content of the image light fastness improver is preferably 0.1 to 10 g / m ² . In the ink jet recording material (1) or (2) of the present invention, the fine pigment particles may be at least one type of fine particles selected from fumed silica, amorphous silica, alumina, and alumina hydrate. preferable. In the ink-jet recording material (1) or (2) of the present invention, the fumed silica particles may have 3 to 5 particles.
It is preferable that it is composed of an aggregate of a plurality of primary particles having an average primary particle diameter of 0 nm and has an average secondary particle diameter of 300 nm or less. In the ink jet recording medium (1) or (2) of the present invention, it is preferable that the ink receiving layer containing the fine pigment particles and the binder further contains a cationic organic compound. In the ink jet recording material (1) or (2) of the present invention, the binder is a latex of a copolymer of a water-soluble polymer compound and a conjugated diene compound, a latex of a vinyl copolymer, a water-dispersible acrylic resin, and a water dispersion. It is preferable to include at least one selected from a water-soluble polyester resin and a water-dispersible polyurethane resin. In the inkjet recording material (1) or (2) of the present invention, the binder is selected from polyvinyl alcohol, partially saponified polyvinyl alcohol, acetoacetylated polyvinyl alcohol, silyl-modified polyvinyl alcohol, cation-modified polyvinyl alcohol, and anion-modified polyvinyl alcohol. At least one
Preferably, it contains a species. In the ink jet recording medium (1) or (2) of the present invention, the substrate may be made of a non-ink-absorbing material. In the ink jet recording medium (1) or (2) of the present invention, it is preferable that the surface of the ink receiving layer has a surface glossiness of 75% or more of 30% or more.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The fading of an ink-jet recorded image by light is achieved by using a fine pigment in an ink receiving layer for the purpose of imparting a high color density to the recorded image or improving the surface gloss. In the case of, it was found that there was a tendency to appear particularly remarkably. It is presumed that the reason for such a phenomenon is that the transparency of the ink receiving layer is high and light is easily transmitted. That is, in order to obtain high ink jet recording characteristics and gloss, as described later, fine pigment particles having a particle diameter of 1 μm or less, particularly, secondary particles formed by aggregating a plurality of primary particles have a particle diameter of 1 μm. The following fine pigments, especially those having a primary particle size of 4 to 3
Although it is preferable to use a fine pigment having a secondary particle diameter of 1 μm or less at 0 nm, when such a fine pigment is used,
There is a tendency that the light fastness of the recorded ink image is reduced.

The present inventors have studied various methods for improving the light fastness of an image without deteriorating the image quality and gloss, and as a result, a phenol compound,
It has been found that the addition of at least one compound selected from the group consisting of boric acid, a borate and a cyclodextrin compound as an image lightfastness improver has a remarkable effect.

The dye contained in the ink is contained in the outermost layer when the ink is fixed as close to the surface of the ink receiving layer as possible. When a large number of images are fixed, a high recording density can be obtained. In this case, it is preferable that an image lightfastness improver is also contained in the uppermost layer of the ink receiving layer.

In order for the ink receiving layer to contain at least one compound selected from the group consisting of a phenolic compound, boric acid, a borate and a cyclodextrin compound as an image light fastness improver, The compound can be coated in advance by blending the compound in the forming coating liquid. However, when an effective amount of the image light fastness improver is added, the strength and water resistance of the obtained ink receiving layer tend to decrease. In addition, when the components of the image light fastness improver, especially boric acid and borate, are mixed in a coating solution, coagulation and thickening may occur, which may make coating difficult. In particular, when a hydroxyl group-containing water-soluble resin, particularly polyvinyl alcohol, is used as the adhesive component, the adhesive strength between the resin and the pigment particles is high, so that both high ink absorption and high coating layer strength can be obtained. it can. However, when such an adhesive is blended, a crosslinking reaction between the adhesive and boric acid or borate is liable to occur, the viscosity is significantly increased, and coating becomes difficult. In this case, a coating layer containing a pigment and an adhesive as main components is provided, and on the surface thereof, an image having at least one compound selected from the group consisting of boric acid, a borate and a cyclodextrin compound is improved. By applying a solution containing the agent, it can be contained in the ink receiving layer. In this case, once the coating layer is applied, the solution can be applied thereon after drying or in an undried state.

The phenolic compound used in the ink jet recording material (1) or (2) of the present invention includes dihydroxybenzene, dihydroxybenzenesulfonic acid and its water-soluble salt, dihydroxybenzenedisulfonic acid and its water-soluble salt, monohydroxybenzene Sulfonic acid and its water-soluble salt, hydroxybenzoic acid and its water-soluble salt, sulfosalicylic acid and its water-soluble salt, arbutin, mononaphthol, mononaphtholsulfonic acid and its water-soluble salt, dinaphthol, dinaphtholsulfonic acid and its water-soluble salt Hydroquinone, hydroquinone sulfonate, hydroquinone disulfonate,
Examples include pyrocatechol, pyrocatechol-3,5-disulfonate, hydroxybenzoate, sulfosalicylate, hydroxybenzenesulfonate, arbutin, various naphthols, and the like. Especially hydroquinone derivatives,
By selecting from pyrocatechol derivatives and phenolsulfonates, more excellent light resistance can be obtained. In particular, by selecting pyrocatechol-3,5-disulfonate (sodium salt is also known as Tiron), p-hydroxybenzenesulfonate, and hydroquinone-β-D-glucoside (arbutin), it is more excellent in light resistance. A recording is obtained. Further, a phenolic compound, sodium,
Magnesium, calcium, aluminum, phosphorus, titanium, iron, nickel, copper, zinc and other salts, such as nitrates, sulfates, phosphates, hydrogen phosphates, citrates,
It is also possible to use a combination of propionate, chloride and the like. By selecting a divalent or higher valent metal salt, especially a chloride of magnesium or calcium, a recording medium having more excellent light resistance can be obtained. . The reason why the light resistance is greatly improved by adding these compounds is not clear, but it is considered that the dyes for inkjet recording which are weak to light irradiation may be stabilized and protected in some form. Phenol compound, boric acid, borate, cyclodextrin compound Examples of boric acid and borate include the following. Orthoboric acid, metaboric acid, tetraborate, orthoborate, diborate, metaborate, tetraborate, pentaborate, octaborate and the like. As the metal for salt formation, an alkali metal (eg, sodium, potassium), an alkaline earth metal (eg, calcium, magnesium, barium) can be used. The following are mentioned as a cyclodextrin compound. α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, alkylated cyclodextrin, hydroxyalkylated cyclodextrin, and cation-modified cyclodextrin. Among them, γ-cyclodextrin is particularly suitable for practical use because it has high water solubility and can be efficiently contained in the ink receiving layer.

The content of the image light fastness improver is preferably 0.1 to 10 g / m ² , more preferably 0.25 to 5 g / m ² , based on the ink jet recording material.
² , more preferably 0.5 to 2.5 g / m ² . When the content of the image light fastness improver is less than 0.1 g / m ² , the desired effect of improving light fastness may not be sufficiently obtained, and when it is used in a large amount exceeding 10 g / m ² , Ink absorption, recording quality, recording density (print density), strength and water resistance of a coating film, and water resistance of a printed portion may be reduced, and a desired gloss may not be easily obtained.

The substrate will be described in detail below. [Substrate] The substrate used in the present invention is an absorbent substrate,
Any non-absorbable substrate may be used. When an absorptive substrate is used, the amount of the ink receiving layer applied can be reduced because the substrate itself has an ink absorbing property. Further, as described later, when the outermost layer is formed by a transfer method such as a casting method, the base material has air permeability, thereby facilitating the production.
When a non-absorbent substrate is used, a recording medium having excellent anti-cockling properties can be obtained. From the viewpoint of improving the surface smoothness and the surface glossiness, it is preferable to use a resin-coated paper such as a plastic film or photographic paper (RC paper). Plastic films and R
When C paper is used, even if it does not depend on the cast transfer method,
High surface gloss can be obtained. Further, when RC paper is used, the same texture as photographic printing paper can be obtained.

(Absorptive Substrate) Examples of the absorbent substrate include high quality paper (acidic paper, neutral paper), art paper, coated paper,
Examples include cast coated paper, kraft paper, and impregnated paper. High smoothness, silver halide photo-like texture (especially whiteness,
If you want to feel, etc., use high smoothness such as base paper for RC paper,
It is preferable to use a paper with high tension (density). The paper substrate used as the absorbent substrate will be described in detail. The paper base is composed mainly of wood pulp and, if necessary, pigment. Wood pulp can use various chemical pulp, mechanical pulp, recycled pulp, and the like.
In order to adjust paper strength, suitability for papermaking, etc., the degree of beating can be adjusted by a beating machine. Pulp beating degree (freeness) is not particularly limited, but generally 250 to 550 ml (CSF: J
ISP-8121) is used.

A pigment is compounded for the purpose of imparting opacity to the paper base or adjusting the ink absorption. Calcium carbonate, calcined kaolin, silica, titanium oxide and the like can be used as pigments for paper base materials. In this case, the compounding amount of the pigment is 1 to
It is preferably about 20%. If the amount of the pigment is too large, the paper strength may be reduced. As a paper base aid, a sizing agent, a fixing agent, a paper strength enhancer, a cationizing agent, a retention improver, a dye, a fluorescent whitening agent and the like can be added. Further, in the size press process of the paper machine, starch, polyvinyl alcohol, a cationic resin, etc. are applied.
By impregnation, the surface strength, sizing degree, etc. of the paper substrate can be adjusted. The size is preferably about 1 to 200 seconds. If the size is too low, there may be operational problems such as wrinkles during coating, and if it is too high, the ink absorptivity of the obtained paper base material will decrease, Cockling may occur significantly. The basis weight of the paper substrate is not particularly limited, but is about ²⁰ to 400 g / m ² . The thickness of the paper is preferably about 20 to 400 μm, and the tension is preferably about 0.6 to 1.2.

(Non-water-absorbing substrate) The non-water-absorbing substrate of the ink jet recording medium of the present invention includes, for example, plastics such as transparent or opaque cellophane, polyethylene, polypropylene, soft polyvinyl chloride, polyester, polycarbonate and polystyrene. Films, or water-absorbing or non-water-absorbing plastic films, resin films, synthetic papers, pulp-based substrates (eg, high-quality paper, neutral paper, photographic paper base paper, art paper, coated paper, cast Coated paper, kraft paper, impregnated paper, etc.) are coated with a non-water-absorbing resin, and a resin-coated body or the like is appropriately used. As the non-water-absorbing coating resin, polyethylene resin,
Polypropylene resin, polyester resin, polyolefin resin, polycarbonate resin, and the like, and those containing a mixture thereof as a main component can be used.
Examples of the polyethylene resin include a low density polyethylene resin, a high density polyethylene resin, and a linear low density polyethylene resin. Examples of the polyester resin include a polyethylene terephthalate resin, a polybutylene terephthalate resin, and a polyester biodegradable resin.

For the purpose of improving the whiteness and / or improving the concealability of plastic films and resin-coated bodies (substrates to be coated or coated resins),
It is also possible to contain a white pigment (preferably a titanium oxide pigment, calcium carbonate, synthetic silica, or a combination thereof). To achieve the above object, it is most preferable to use a titanium oxide pigment. As other white pigments, known and publicly available pigments such as synthetic silica, zinc oxide, talc and kaolin can be used.

Since plastic films are expensive, and it is difficult to obtain a silver halide photographic-like texture (especially whiteness and hand), high-quality paper, photographic paper base paper, and art whose main component is pulp and has high smoothness Paper, coated paper or cast coated paper, polyethylene-based resin, polypropylene-based resin, polyester-based resin, polyolefin-based resin,
It is preferable to use resin-coated paper coated with high smoothness using a resin containing a polycarbonate-based resin or a mixture thereof as a main component.

In particular, it is particularly preferable to use a resin-coated paper (RC paper) obtained by coating a photographic paper base paper with a polyolefin resin such as a polyethylene resin so as to have high smoothness. The resin coating is performed by extruding a hot-melted resin, for example, a polyolefin-based resin from a die head, coating the base paper surface, and immediately cooling and solidifying it with a cooling roll. As the resin coating layer on the side where the ink receiving layer is provided, in order to obtain high smoothness, it is preferable to use a cooling roll having a mirror surface or a smooth surface equivalent thereto. Further, for the purpose of obtaining a photographic paper-like texture (especially a feeling of touch) and preventing curling of a recording medium, a polyethylene-based resin or other polyolefin is also provided on the surface (rear surface) opposite to the recording surface. It is preferable to apply a coating with a system resin. The back surface coating layer is preferably a matte surface in order to give the ink jet recording medium of the present invention the texture of photographic paper, and to improve printer transportability, and the matte surface has a matte surface. It is better to use a cooling roll.

The thickness of the coating layer is not particularly limited.
It is preferably in the range of 100 μm, more preferably 5 to 50 μm, even more preferably 7 to 35 μm. If the thickness is too small, the effect of the coating may be insufficient, and if it is too large, the texture may be poor. In order to prevent the curling of the recording medium, the thickness of the coating on the recording surface and the back surface may be adjusted, or the type of the coating resin may be appropriately selected. The coating resin may contain a white pigment, preferably a titanium oxide pigment, calcium carbonate, synthetic silica, or a mixture of two or more thereof. Most preferably, a titanium oxide pigment is used.

When a non-absorbent substrate is used as the substrate,
For the purpose of increasing the adhesion between the recording surface side surface of the substrate and the recording layer, the substrate may be previously subjected to an adhesion treatment or an adhesion treatment. In particular, when a resin-coated paper is used, it is preferable to perform a corona discharge treatment on the paper and / or to provide an undercoat layer of gelatin, polyvinyl alcohol, or the like.

The back surface of the base material can be subjected to treatments such as improvement of transportability, prevention of charging and prevention of blocking. Backside treatment involves chemical treatment or the addition of other constituent layers such as a coat layer. Alternatively, a pressure-sensitive adhesive layer may be provided on the back surface and bonded to a release sheet to form a pressure-sensitive adhesive sheet. Further, on the back surface, a magnetic recording layer, an inkjet recording layer, a coating layer for printing other than inkjet, a magnet layer and other coating layers, and a treatment layer can be appropriately provided.
These treatments and coatings may be performed before or after the ink receiving layer of the present invention is provided on the substrate.

The smoothness of the substrate surface is not particularly limited,
In order to obtain a highly glossy and highly smooth recording layer surface, the smoothness of the substrate surface must be 300 seconds (Oken type, J. TAPPI No. 5).
It is preferable that it is above. Furthermore, the opacity of the substrate is not particularly limited, but in order to obtain a photographic paper-like texture (especially luminous whiteness) in the obtained recording medium,
The opacity (JIS P8138) of the substrate is preferably at least 85%, more preferably at least 93%.

[Ink receiving layer] Next, the ink receiving layer will be described. The ink receiving layer contains a pigment and an adhesive as main components. Further, in order to improve the ink fixability (printing water resistance and color development), it is preferable that a cationic compound is contained in the ink receiving layer. The cationic compound, when the ink receiving layer has a multilayer structure of two or more layers,
At least one of them may be contained. However, in order to increase the printing density, it is preferable that the compound be contained in the outermost layer as much as possible, preferably the outermost layer. In the present invention, an image lightfastness improver comprising at least one compound selected from the group consisting of phenol compounds, boric acid, borates and cyclodextrin compounds is contained in at least one of the ink receiving layers having a multilayer structure. Although it is contained, the layer containing a large amount of the cationic resin preferably contains a large amount of an image lightfastness improver.

(Pigment) In the present invention, the pigment contained in the ink receiving layer is, specifically, kaolin, clay,
Calcined clay, amorphous silica (amorphous silica), zinc oxide, alumina (aluminum oxide), aluminum hydroxide, alumina hydrate (pseudo boehmite, etc.), calcium carbonate, satin white, aluminum silicate, zeolite,
Various pigments known and used in the general coated paper manufacturing field such as synthetic zeolite, sepiolite, smectite, synthetic smectite, magnesium silicate, magnesium carbonate, magnesium oxide, diatomaceous earth, and hydrotalcite can be used. These may be used alone or in combination with two or more.
More than one species may be used in combination. Among these pigments, it is preferable to use, as a main component, amorphous silica, alumina, alumina hydrate, and / or zeolite having high transparency and ink absorbability.

(Fine Pigment) In order to obtain high print density and high gloss, the ink receiving layer of the present invention, particularly the outermost layer, preferably contains a fine pigment having an average particle diameter of 1 μm or less. As such a fine pigment, for example, fine primary particles such as colloidal silica may be used, but fine particles in the form of secondary particles formed by agglomeration of a plurality of primary particles are preferably used. When fine pigment secondary particles having an average primary particle size of 3 to 40 nm and an average secondary particle size of 1 μm or less are used, the ink absorbing and fixing properties of the ink receiving layer obtained are remarkably improved.

The fine pigment is formed by aggregating primary particles, preferably primary particles having an average primary particle diameter of 3 to 40 nm, and pulverizing secondary particles having an average particle diameter of 1 μm or more.
Can be obtained in a dispersed manner. Specific examples of such secondary particles include kaolin, clay, calcined clay, fumed silica, amorphous silica (amorphous silica), zinc oxide, alumina (aluminum oxide), and alumina hydrate (pseudo boehmite, etc.). ), Aluminum hydroxide, calcium carbonate, satin white, aluminum silicate, zeolite, synthetic zeolite, sepiolite, smectite, synthetic smectite, magnesium silicate, magnesium carbonate, magnesium oxide, diatomaceous earth, hydrotalcite, etc. Various publicly known pigments can be used.
These can be used alone or in combination of two or more. Among these, it is preferable to use highly transparent amorphous silica, alumina, or alumina hydrate.

These secondary particles were treated with an average secondary particle diameter of 1
When the pulverization / dispersion treatment is performed until the particle diameter becomes equal to or less than μm, for example, secondary particles having a secondary particle diameter of the order of several μm are placed in a medium such as water, and the solid content concentration is generally about 5 to 20%. After dispersing so that it is subjected to an ultrasonic homogenizer, a pressure homogenizer, a high-speed rotation mill, a roller mill, a container driving medium mill, a medium stirring mill, or a jet mill, etc. It can be obtained by reducing the diameter. Moreover, you may classify as needed.

The fine pigment thus treated is generally obtained as a slurry or a colloidal dispersion having a solid content of about 5 to 20%. In particular, examples of highly transparent amorphous silica include fumed silica (vapor phase silica) which has been treated so that the average secondary particle diameter is 1 μm or less. In fumed silica, the purity of silicon tetrachloride as a raw material can be made relatively high by distillation, and the production process of a closed system is possible, so that contamination of impurities can be prevented even in the production process. Such high-purity fumed silica is effective for forming an ink receiving layer having high printing density and high gloss.

Particularly, highly transparent alumina includes fumed alumina and γ-alumina which have been treated so that the average secondary particle diameter is 1 μm or less. As highly transparent alumina hydrate, Pseudo boehmite which has been treated so that the average secondary particle diameter is 1 μm or less. These aluminas and alumina hydrates have high transparency and, in addition, the particle shape is plate-like, column-like, or needle-like, so that the self-adhesiveness is high and the coating liquid containing these is dried. Then, a film having high surface smoothness can be formed, and as a result, the surface has less diffuse reflection and a higher gloss. Furthermore, particularly, the highly transparent alumina-containing ink receiving layer can exhibit high ink fixability without adding a cationic compound thereto.

The fumed silica used in the present invention comprises:
It is preferable that the fumed silica has an average secondary particle diameter of 300 nm or less composed of primary particles having an average primary particle diameter of 3 to 40 nm. Generally, synthetic silica has impurities such as metal ions in the raw material, and impurities are mixed in the production process. Synthetic silica containing many impurities has a large refractive index and is inferior in transparency. The fumed silica used in the present invention is generally obtained by burning silicon tetrachloride in an oxyhydrogen flame (in a flame of oxygen and hydrogen). By changing the manufacturing conditions, the specific surface area is 50-600m
Silica in the range of ² / g is obtained. Fumed silica can be made relatively high in purity by highly purifying silicon tetrachloride as a raw material by distillation. Furthermore, since silicon tetrachloride can be produced by burning and hydrolyzing in a gas phase by a closed system, contamination of impurities can be prevented even in the production process. Utilizing the high purity by suppressing the contamination of impurities in the manufacturing process in this way, the semiconductor industry that requires particularly high purity (for example, abrasives for silicon wafers, abrasives for ICs, semiconductor encapsulation, etc.) Agents, crucibles for pulling up Si single crystals) and optical communication industry (for example, quartz glass for optics). As used in the present invention, the purity of fumed silica in order to obtain a high printing density, SiO ₂ content of 99.3%
Or more, more preferably 99.5% or more, and 9
It is more preferably at least 9.8%, most preferably at least 99.9%. By the way, high SiO
₂ Content cannot be obtained. For example, as a commercially available wet process silica, Tokusyl U manufactured by Tokuyama Co., Ltd. has an SiO ₂ content of 85 to 90%, and Siloid 72 manufactured by Fuji Devison Co., Ltd. has a SiO ₂ content of 99.2%, manufactured by Shionogi & Co., Ltd. In the case of Carplex # 80, the SiO ₂ content is 88%,
In the case of Nip Seal U manufactured by Nippon Silica Co., the SiO ₂ content is 94%. The primary particles of fumed silica are spherical particles having the smallest diameter among existing powders. Usually, in the dispersion, the primary particles are present in an aggregated form.

When such high-purity fumed silica is contained, high printing density and high gloss can be obtained. Further, fumed silica has high dispersibility, and it is possible to obtain silica having a particle size on the order of nm by using a general dispersion method. Furthermore, by mixing a fumed silica and a cationic compound and using a coating liquid containing a slurry-like mixture dispersed or ground by mechanical dispersion, high printing density, surface smoothness, glossiness, image water resistance, etc. High print quality comparable to silver halide photography is obtained.

The fumed silica used in the present invention is preferably fumed silica having an average primary particle diameter of 3 to 40 nm and an average secondary particle diameter of 300 nm or less in order to obtain higher printing density and higher gloss. It is preferred to use. Three
The ultrafine particles having a size of less than 00 nm are obtained by pulverizing and dispersing a commercially available pigment by mechanical means, that is, breaking doping.
It can be obtained by the wn method (a method of subdividing a bulk raw material). Examples of mechanical means include use of a homogenizer, a nanomizer, an optimizer, a high-speed rotation mill, a sand grinder, and the like. The average particle diameter in the present invention is a value observed with an electron microscope (transmission type or scanning type) ("Particle Handbook", Asakura Shoten,
52).

In order to obtain the same recording density as that of a silver salt photograph, the ultrafine particles are more preferably secondary particles having an average particle diameter of 10 to 300 nm formed by aggregating primary particles having an average particle diameter of 3 to 40 nm. . The average secondary particle diameter of the ultrafine particles is 30
If it exceeds 0 nm, there is a possibility that the glossiness of the ink jet recording medium or the recording density may decrease due to the decrease in transparency. In particular,
The ultrafine particles are preferably fumed silica of high purity. Fumed silica not only provides ultrafine particles with relatively weak mechanical force, but also has a small refractive index,
Because of high transparency, higher gloss and higher printing density can be obtained. Since the aqueous dispersion of fumed silica has thixotropic properties, it forms aggregates in a static state where external force is removed. The average particle size of the fumed silica according to the present invention is as follows: a 5% aqueous silica dispersion (in the case of a slurry, dilute it to 5% in advance) with a homomixer.
After stirring and dispersing at 000 rpm for 10 minutes, the mixture was further pulverized under the conditions of a pressure homogenizer (trade name: GM-2, manufactured by SMT Corporation) at a pressure of 400 kgf / cm ² , and then a transmission electron microscope in a dispersion state as it was. Is the particle size observed in.

According to the present invention, fumed silica is cationically modified with alumina or a silane coupling agent (for example, n-2-aminoethyl-3-aminopropyltriethoxysilane) to improve the water resistance of the ink after printing. It may be used later. It is preferable to include a cationic resin in the recording layer as needed. More preferably, it is contained in the uppermost layer. The type of the cationic resin to be added is not particularly limited, but various resins forming a salt insoluble with a sulfone group, a carboxyl group, or the like of the dye of the inkjet ink, secondary amine, tertiary amine, And cationic resins containing quaternary ammonium salts and the like. Specific examples include polyethyleneimine, polyvinylpyridine, polyvinylamine, a polymer of monoallylamine hydrochloride, a polymer of diallylamine hydrochloride, a copolymer of monoallylamine hydrochloride-diallylamine hydrochloride, and a (meth) acrylamidoalkyl quaternary ammonium salt. And polyalkylene polyamine / dicyandiamide condensate, secondary amine / epichlorohydrin addition polymer, and compounds such as polyepoxyamine. The amount of the cationic resin to be added is adjusted in the range of 1 to 40 parts, preferably 3 to 25 parts, per 100 parts of the pigment.

In general, silica exhibits an electrical minus because of the presence of silanol groups on the surface, and aggregates when mixed with a cationic resin. Average particle size is 1μ
When the average particle diameter is less than 1 μm, it is desirable to apply a strong mechanical pulverizing force. Examples of the strong mechanical pulverization include a high-speed rotation of a homomixer, an ultrasonic homogenizer, a pressure homogenizer, an optimizer, a nanomizer, a high-speed rotation mill, a roller mill, a container driving medium mill, a medium stirring mill, a jet mill, and a sand grinder. For more effective dispersion or pulverization, it is preferable to use pressure pulverization.

In the present invention, the ink receiving layer may contain another pigment in addition to the specific fine pigment. For example, amorphous silica, kaolin, clay, calcined clay, zinc oxide, tin oxide, magnesium sulfate, alumina, aluminum hydroxide, alumina hydrate, pseudoboehmite, calcium carbonate having an average particle size of greater than 1 μm,
Satin white, aluminum silicate, smectite,
Zeolite, magnesium silicate, magnesium carbonate,
Various pigments generally known and used in the coated paper field, such as magnesium oxide, diatomaceous earth, styrene-based plastic pigment, urea resin-based plastic pigment, and benzoguanamine-based plastic pigment, may be included as additional pigments. In this case, in order to obtain high ink absorbency, high print density and high gloss, the amount of the additional pigment is preferably 50% or less, more preferably 20% or less.

The average particle size in the present invention is a particle size observed and measured using an electron microscope (SEM or TEM). Take a picture, measure the Martin diameter of the particles in an area of 5 cm square, and average them ("Particle Handbook"
(Asakura Shoten), p. 52, 1991 and the like. ). The average particle size of the fine pigment preferably used in the present invention is 1 μm or less. More preferably, 1
0 nm to 500 nm, and more preferably 15 nm to 30 nm.
0 nm, and more preferably 20 nm to 200 nm. In the case of a fine pigment complexed with a cationic compound as described below, the suitable secondary particle diameter is the same as described above. The average particle size of the secondary particles of the fine pigment is 1 μm
When the ratio exceeds the above range, the transparency of the gloss layer is reduced, the coloring property of the dye fixed in the gloss layer is reduced, and it tends to be difficult to obtain a high print density.

The fine pigment is preferably a secondary particle. In this case, the average particle size of the primary particle is preferably 3 nm or more and 40 nm or less, more preferably 5 nm or less.
nm to 30 nm, more preferably 7 nm to 2
0 nm or less. When this primary particle diameter is less than 3 nm,
The voids formed between the mutually agglomerated primary particles become extremely small, the ability to absorb the solvent and the ink in the ink is reduced, and it becomes difficult to obtain a desired image quality. If the average primary particle size exceeds 40 nm, the particle size of the aggregated secondary particles becomes excessive, and the ink receiving layer (particularly the outermost layer)
Of the dyes fixed in the ink receiving layer (especially the outermost layer), the color developability of the dye decreases, and it becomes difficult to obtain a desired print density. The weight ratio of the fine pigment to all the pigments in the ink receiving layer (particularly the outermost layer) is desirably 50% or more in order to maintain good transparency.
When the weight ratio of the fine pigment in all the pigments is less than 50%,
In some cases, the transparency of the obtained ink receiving layer is significantly reduced, and the image quality such as print density may be reduced.

(Blending of cationic compound) It is preferable that a cationic compound for fixing the anionic dye component in the ink is blended in at least one of the ink receiving layers. In order to fix an ink image having a high print density, it is desirable to fix the ink dye as close to the surface as possible, and it is preferable that the cationic compound is blended in the outermost layer or the inner layer near the outermost layer. In order to mix a cationic compound, the pigment may be mixed with a cationic compound. At this time, since a fine pigment is used, aggregation may occur. In addition, for example, amorphous silica is generally anionic and thus easily aggregates. In this case, after adding a cationic compound to the pigment, a method of subjecting the pigment to pulverization / dispersion treatment, or after pulverizing / dispersing the pigment to some extent, adding the cationic compound to the pigment, and further forming the formed aggregates It is preferable to employ a method of pulverization and dispersion. As a result, it is considered that at least a part of the pigment particles exists in a form complexed with the cationic compound. As described above, the cationic compound is blended in the process of crushing and dispersing the pigment particles,
Preferably, at least a part of the pigment is compounded, but a cationic compound may be further added to the cationized fine pigment in order to adjust the print water resistance, print density, print bleeding and other qualities. In this case, since the treated fine pigment has already been cationized, aggregation is less likely to occur even if a cationic compound is further added.

(Cationic Compound) Examples of the cationic compound include a cationic resin and a low molecular weight cationic compound (for example, a cationic surfactant and the like). It is preferable to use a cationic resin from the viewpoint of the effect of improving the printing density, and it can be used as a water-soluble cationic resin or an aqueous cationic resin emulsion. Further, a cationic organic pigment in which the cationic resin is insolubilized by means such as cross-linking to form a particulate form may be used. Such a cationic organic pigment, when polymerizing a cationic resin, is a method of copolymerizing a polyfunctional monomer and crosslinking the same to form a crosslinked resin, or a method of forming a reactive functional group (hydroxyl group, carboxyl group,
It can be produced by a method in which a crosslinking agent is added to a cationic resin having an amino group, an acetoacetyl group, or the like, if necessary, and the resin is crosslinked by heat, radiation, or the like.

The cationic compound, particularly the cationic resin, may sometimes serve as an adhesive for the ink receiving layer. The following can be illustrated as the cationic resin. Specifically, 1) polyalkylene polyamines such as polyethylene polyamine and polypropylene polyamine or derivatives thereof, 2) secondary amine groups, tertiary amine groups, and quaternary amine groups
Acrylic resin having quaternary ammonium group, 3) polyvinylamine, polyvinylamidines, 4) dicyanic cation resin represented by dicyandiamide-formalin polycondensate, 5) polyamine-based cation represented by dicyandiamide-diethylenetriamine polycondensate resin,
6) epichlorohydrin-dimethylamine addition polymer,
7) Dimethyl diallyl ammonium chloride-SO2
Copolymer, 8) diallylamine salt-SO2 copolymer,
9) dimethyldiallylammonium chloride polymer,
10) Cationic resins such as polymer of allylamine salt, 11) polymer of quaternary salt of dialkylaminoethyl (meth) acrylate, and 12) copolymer of acrylamide-diallylamine salt.

The cationic compound can be used in an amount of 1 to 100 parts by weight, more preferably 5 to 50 parts by weight, based on 100 parts by weight of the total pigment in the layer containing the cationic compound. If the compounding amount is insufficient, the effect of improving the printing water resistance, the printing density, etc. may not be sufficiently obtained, and if it is used excessively, the printing density of the obtained ink image decreases, Some bleeding may occur.

(Adhesive; Binder) Examples of the adhesive include water-soluble polymers such as polyvinyl alcohol, polyvinylpyrrolidone, casein, soybean protein, synthetic proteins, starch, cellulose derivatives such as carboxymethylcellulose and methylcellulose, and water-dispersible compounds. Resins, for example, styrene-butadiene copolymer, conjugated diene-based polymer latex such as methyl methacrylate-butadiene copolymer, vinyl-based copolymer latex such as styrene-vinyl acetate copolymer, aqueous acrylic resin, aqueous polyester resin Various adhesives known and used in the field of coated paper, such as water-based polyurethane resin and the like, can be blended in the ink receiving layer within a range not to impair the effects of the present invention.

When the ink-receiving layer contains a water-soluble polymer, especially a water-soluble polymer having a hydroxyl group, particularly polyvinyl alcohol (PVA) as a main component of the binder, these have an adhesive force with the pigment particles. As a result, an ink receiving layer having high film strength can be obtained. Although the reason is not clear, the image light fastness improver containing at least one compound selected from the group consisting of boric acid, borate and cyclodextrin compound used in the present invention is not compatible with PVA. Tends to be particularly effective. Further, when boric acid or borate is used, a higher effect tends to be exerted by coexisting it with partially saponified PVA.

The PVAs used in the present invention include completely saponified PVA, partially saponified PVA, and various modified PVAs.
A, such as acetoacetylated PVA, silyl-modified PV
A, cation-modified PVA, and anion-modified PVA. As PVAs have a higher degree of polymerization, they tend to have better adhesive strength and water resistance. Therefore, it is preferable to use PVAs having a higher degree of polymerization. As the degree of polymerization of the PVAs used in the present invention is preferably about 500 to 5,000 because the properties are easily reduced. Also, as the degree of saponification is higher, the adhesive strength and water resistance tend to be improved. Therefore, it is preferable to use PVAs having a high degree of saponification. Tends to increase and the dissolution stability tends to decrease. Generally, the saponification degree is preferably 80% or more. As described above, when used in combination with boric acid or a borate, PVA compounds preferably have a somewhat lower degree of saponification,
In this case, the degree of saponification is preferably about 70 to 99%.

The amount of the adhesive in the ink receiving layer of the present invention is preferably 1 to 200 parts by weight, more preferably 10 to 100 parts by weight, based on 100 parts by weight of the total pigment. If the amount of the adhesive is too small, the desired effect may not be obtained, and the strength of the coating layer may be insufficient, the surface may be easily damaged, and powder may fall off. Conversely, if the amount is too large, the resulting ink receiving layer may have insufficient ink absorbency, and may not be able to achieve desired ink jet recording suitability.

(Release Agent, etc.) As described below, when the outermost layer is formed by a transfer method, the release agent used in the production of ordinary coated paper for printing or cast paper for printing is replaced with the outermost layer. It can be blended in a layer coating solution. Such release agents include higher fatty acid amides such as stearic acid amide; polyolefin waxes such as polyethylene wax and polypropylene wax; higher fatty acid alkali salts such as calcium stearate, zinc stearate, potassium oleate and ammonium oleate; And lecithin,
Examples include silicone compounds such as silicone oil and silicone wax.

The amount of the release agent is preferably 0.1 to 50 parts by weight, more preferably 0.5 to 30 parts by weight, and further preferably 1 to 100 parts by weight based on 100 parts by weight of the total pigment.
-20 parts by weight. If the compounding amount is too small, the effect of improving the releasability may be insufficient. Repelling and a decrease in recording density may occur. In order to adjust the whiteness, viscosity, fluidity, etc. of the ink receiving layer coating composition, pigments, defoamers, colorants, and fluorescent enhancers used in general printing coated paper and inkjet paper are used. Various auxiliaries such as whitening agents, antistatic agents, preservatives and dispersants, and thickeners are appropriately added.

[Production method] Plastic film or RC
When a substrate having particularly high smoothness such as paper is used, and particularly when a fine pigment (for example, the average secondary particle diameter is 500 nm or less) is used, an ink receiving layer having high gloss can be obtained. Further, the gloss can be further improved by a super calender treatment (thermal super). Even when a normal (not very high smoothness) base paper is used as the base material, the gloss can be improved by forming the outermost layer by the transfer method.

(Transfer method) The transfer method is a method in which a coating layer is coated with a cast drum having smoothness (a drum made of mirror-finished metal, plastic, glass, etc.), a mirror-finished metal plate, a plastic sheet or film, a glass plate This method is to obtain a smooth and glossy surface of the coating layer by drying in a state of being in close contact with the mirror surface such as that described above, and copying the smooth mirror surface onto the coating layer.

(Cast method) As a method of forming an ink receiving layer (outermost layer) by a transfer method, a coating liquid is applied onto a substrate (if an undercoat layer is provided), and A method in which, while the liquid layer is in a wet state, it is pressed against a heated mirror drum or the like to finish by drying (wet casting method), or the coating liquid layer is dried once, then re-wetted and then heated to a heated mirror drum And a method of finishing by pressing and drying (rewet casting method). Furthermore, after applying the coating liquid directly to a heated mirror drum or the like, this is pressed against the surface of the base material (or the surface of the lower layer when an undercoat layer is provided),
A method of finishing by drying (precast method) can also be adopted. Further, the coating liquid is applied onto the base material (on the surface of the undercoat layer, if provided), and the applied layer is dried to a certain extent. A method of finishing by pressing and drying can also be used. Here, "semi-dried" means that the fluidity of the coating layer is almost lost, but that the coating layer contains a large amount of water.
0% (that is, 20 to 100 parts by weight of the absolute dry weight of the coating layer)
(Including 400 parts by weight of water).

The coating solution is applied onto the substrate (if an undercoat layer is provided), and while the coating layer is in a wet state, it is pressed against a heated mirror drum or the like and dried to finish. In this case, a method of promoting immobilization of the coating liquid may be employed for the purpose of obtaining a coating liquid layer having a uniform and sufficient coating amount. As this method, for example, (1) in a base material or an undercoat layer,
A method of blending a gelling agent that promotes immobilization of the outermost layer coating solution, (2) a gelling agent that promotes immobilization of the outermost layer coating solution on the base material or the undercoat layer (3) a method of coating and impregnating the surface of the coating liquid layer with a gelling agent that promotes immobilization of the coating liquid after coating the outermost layer coating liquid; Or (4) a method in which a gelling agent that promotes immobilization in the process of drying the coating liquid is blended in the coating liquid for the outermost layer.

(Film Transfer Method) As another method of forming the ink receiving layer (outermost layer) by a transfer method, there is a film transfer method. In the film transfer method, a coating solution is applied on a substrate (on an undercoat layer, if provided), and while the coating solution layer is in a wet state, or once dried and rewet, A smooth film or sheet is superposed thereon, and after drying as it is, a method of peeling the smooth film or sheet, a coating liquid is applied on the smooth film or sheet, and the coating liquid layer is in a wet state. There is a method in which, after drying or once re-wetting, the substrate or the undercoat layer surface is overlaid, dried as it is, and then a smooth film or sheet is peeled off. Moreover, in the said method, it is also possible to peel off the film or sheet, and then completely dry it, without drying or partially drying (when the film or sheet can be peeled off) in a state where the film or sheet is stacked. . In the case of the above-mentioned film transfer method, the image light-fastness comprising at least one compound selected from the group consisting of boric acid, borate and a cyclodextrin compound is formed on the surface of the ink receiving layer coated and formed into a film. Apply a solution containing an enhancer,
It can be contained in the ink receiving layer.

(Coating Method) When the above-mentioned ink receiving layer is coated, a blade coater, an air knife coater, a rod blade coater, a roll coater, a brush coater, a champlex coater, a bar coater, a gravure coater, a die coater, a curtain, etc. Various known coating apparatuses such as a coater and a slide coater can be used. The coating amount of the receptor layer outermost layer will vary with the coating amount of the inner undercoat layer, generally, 1 to 50 g / m ² on a dry solids
And more preferably 2 to 30 g /
m ² , and more preferably 3 to 20 g / m ² . If the coating amount is less than 1 g / m ² , the printing density and gloss of the recorded image may be insufficient, and if the coating amount is more than 50 g / m ² , the effect is saturated and cost is reduced. It can be disadvantageous.

[Undercoat layer] The ink receiving layer can have a multilayer structure of two or more layers. Layers other than the outermost layer are referred to as undercoat layers. The undercoat layer is composed mainly of a pigment and an adhesive. The pigment in the undercoat layer may be a fine pigment, but may have a particle diameter larger than that used in the outermost layer. When two or more undercoat layers are provided and a fine pigment is used for the undercoat layer adjacent to the outermost layer, at least the pigment particles for the lowermost layer of the undercoat layer are layers adjacent to the outermost layer of the undercoat layer. It is preferred to use a larger one than used. In this case, the absorption capacity and the absorption speed increase. In order to obtain a high gloss layer without using a transfer method, it is necessary that the smoothness of the surface of the undercoat layer is high to some extent. Therefore, the particle size of the pigment particles for the undercoat layer must be 1 μm or less. Is preferred.

Specific examples of the pigment for the undercoat layer include kaolin, clay, calcined clay, amorphous silica (amorphous silica), zinc oxide, alumina (aluminum oxide), aluminum hydroxide, and alumina water. Japanese, calcium carbonate, satin white, aluminum silicate, alumina, colloidal silica, zeolite, synthetic zeolite,
Sepiolite, smectite, synthetic smectite, magnesium silicate, magnesium carbonate, magnesium oxide,
Various pigments known and used in the general coated paper manufacturing field, such as diatomaceous earth, styrene-based plastic pigment, hydrotalcite, urea resin-based plastic pigment, and benzoguanamine-based plastic pigment, are used alone or in combination of two or more. be able to. Among these, amorphous silica with high ink absorption, alumina,
It is preferable to use alumina hydrate and zeolite as main components.

Examples of the adhesive for the undercoat layer include proteins such as casein, soybean protein and synthetic protein, various starches such as starch and oxidized starch, polyvinyl alcohol, cellulose derivatives such as carboxymethylcellulose and methylcellulose, and styrene-butadiene. Polymers, conjugated diene-based polymer latex of methyl methacrylate-butadiene copolymer, acrylic-based polymer latex, vinyl-based polymer latex such as ethylene-vinyl acetate copolymer, etc., are generally used for coated paper. Conventionally known adhesives can be used alone or in combination of two or more.

The mixing ratio of the pigment and the adhesive depends on the kind thereof, but generally, the adhesive is 1 to 10 parts by weight based on 100 parts by weight of the pigment.
0 parts by weight, preferably in the range of 2 to 50 parts by weight. In addition, various auxiliaries such as a dispersant, a thickener, an antifoaming agent, an antistatic agent, and a preservative used in the production of general coated paper are appropriately added. A fluorescent dye and a colorant can be added to the undercoat layer.

A cationic compound can be incorporated in the undercoat layer in order to fix the dye component in the ink for ink jet recording. When the particle size of the pigment particles in the undercoat layer is somewhat large, it is effective to fix the ink dye as much as possible in the outermost layer provided on the undercoat layer in order to increase the printing (recording) density. For this purpose, it is preferable to incorporate a larger amount of the cationic compound in the outermost layer than in the undercoat layer. When the particle size of the pigment particles in the undercoat layer is sufficiently small and the transparency of the obtained undercoat layer is high, even if the ink is fixed in the undercoat layer, the decrease in print density is small. There is no problem even if a cationic compound is incorporated therein.

The composition for an undercoat layer composed of the above materials is generally adjusted to a solid concentration of about 5 to 50% by weight and can be formed on a substrate at a dry weight of ² to 100 g / m ^2. It is preferably about 5 to 50 g / m ² , more preferably about 10 to 30 g / m ² . However, when two or more undercoat layers are provided, their coating amounts can be appropriately adjusted. Here, if the coating amount is too small, the ink absorbency becomes insufficient, and a sufficiently high gloss may not be obtained when a gloss layer is provided. In some cases, the strength of the coating layer may be reduced, and the powder may easily fall off or be damaged. The composition for an undercoat layer can be applied and dried using various known and publicly-applied coating apparatuses similar to those for coating the outermost layer. Further, if necessary, a smoothing treatment such as super calendering or brushing can be performed after the undercoat layer is dried. Further, the undercoat layer may be manufactured by a transfer method.

(Ink) The ink used in the ink jet recording method of the present invention contains, as essential components, a dye for forming an image and a solvent for dissolving or dispersing the dye, and further contains various dispersants as necessary. Various auxiliaries such as a surfactant, a viscosity adjuster, a specific resistance adjuster, a pH adjuster, a fungicide, and a stabilizer for dissolving or dispersing the recording material may be appropriately contained. As recording dyes used in ink,
Examples thereof include direct dyes, acid dyes, basic dyes, reactive dyes, food dyes, disperse dyes, oil dyes, and various pigments, and any of conventionally known recording dyes can be used without any particular limitation.
The content of the dye varies depending on the type of the solvent component, the characteristics required for the ink, and the like. However, in the ink used for the recording medium of the present invention, the compounding amount in the conventional ink, that is, 0.1 to 20 There is no particular problem at a content of about weight%.

As the solvent of the ink used in the recording medium of the present invention, water and various water-soluble organic solvents such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, etc. C1-C4 alkyl alcohols, ketones or ketone alcohols such as acetone and diacetone alcohol, polyalkylene glycols such as polyethylene glycol and polypropylene glycol, ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, and thiol Alkylene glycols having 2 to 6 alkylene groups such as diglycol, hexylene glycol and diethylene glycol, amides such as dimethylformamide, tetrahydrofuran Ethers such as down, glycerin, ethylene glycol methyl ether, diethylene glycol methyl (ethyl) ether, and the like lower alkyl ethers of polyhydric alcohols such as triethylene glycol monomethyl ether.

Although the above description has been made with respect to dye inks, pigment type inks have recently become widespread. Pigment inks are generally inferior to dye inks in the sharpness of color images, but have the advantage of being excellent in water resistance and light resistance of recorded images. The pigment ink is an ink in which an organic or inorganic pigment particle component is dispersed in a solvent, that is, water or / and an organic solvent.

Examples of the organic solvent for the pigment ink include alkyl alcohols having 1 to 4 carbon atoms such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol and isobutyl alcohol, acetone and diacetone alcohol. Ketone or ketone alcohols such as, polyethylene glycol, polyalkylene glycols such as polypropylene glycol, ethylene glycol, polypropylene glycol, butylene glycol, triethylene glycol,
Alkylene glycols having 2 to 6 alkylene groups such as thiodiglycol, hexylene glycol and diethylene glycol, amides such as dimethylformamide, ethers such as tetrahydrofuran, glycerin, ethylene glycol methyl ether, diethylene glycol methyl (ethyl) ether; Examples include lower alkyl ethers of polyhydric alcohols such as triethylene glycol monomethyl ether, (iso) paraffinic hydrocarbons, and the like.

Among the above solvents, those using a solvent containing water as a main component are called aqueous pigment inks, and those containing an oil solvent as a main component are called oil pigment inks. Examples of organic pigments for pigment inks include pigments such as azo, phthalocyanine, perlin, isoindolinone, imidazolone, pyranthrone, and thioindigo pigments.Examples of inorganic pigments include carbon black, graphite, and synthetic pigments. Iron oxide yellow, transparent red iron oxide, titanium yellow, molybdate orange, cuprous oxide, cobalt blue, ultramarine, C.I. I. Pigment Yellow (yellow ink), C.I. I. Pigment Blue
(Cyan ink), C.I. I. Pigment Red
Pigments such as (magenta ink) can be exemplified.

As the dispersant for the pigment ink, various surfactants, low molecular weight dispersants, and resin dispersants having a hydrophilic functional group and a hydrophobic functional group are used. Further, an aqueous resin can be added for the purpose of adjusting the viscosity of the ink or improving the fixing property. The pigment and the dispersant are blended in a solution, and the pigment particles are pulverized into fine dispersed particles using a disperser such as a paint shaker or a sand mill.
A method of filtering and removing coarse particles using a filter of 0 μm or less to obtain a pigment ink is usually employed. Although the solid content concentration of the pigment ink is not particularly limited, it is generally 0.1%.
5 to 30% by weight. The particle size of the pigment dispersed in the pigment ink is generally about 50 nm to 500 nm.

[0076]

The present invention will be described in more detail with reference to the following examples, but it should be understood that the present invention is by no means restricted to such specific examples. Parts and% in the examples are parts by weight and% by weight, respectively, unless otherwise specified. Substrates and fine pigment particles used in the following Examples and Comparative Examples were prepared by the following method.

Preparation of Substrate [Support A] Wood pulp (LBKP; CSF 500 ml)
100%, Ansilex (calcined kaolin) 10 parts, commercial sizing agent 0.05 part, sulfuric acid band 1.5 parts, wet paper strength agent 0.5 part, starch pulp of 0.5% concentration consisting of 0.75 part A slurry was prepared. This pulp slurry was paper-made with a fourdrinier paper machine and passed through a drier and a machine calender to produce a paper substrate (support A) having a basis weight of 120 g / m ² and a tension of 0.80. This support A had a Steckigt sizing degree of 10 seconds.

[Support B] CSF (JIS P-812)
1) Softwood bleached kraft pulp (N
BKP) and bleached hardwood kraft pulp (LBKP) beaten to 280 ml of CSF were mixed at a weight ratio of 2: 8 to prepare a pulp slurry having a concentration of 0.5%. To this pulp slurry, 2.0% of cationized starch, 0.4% of alkyl ketene dimer, 0.1% of anionized polyacrylamide resin, and 0.7% of polyamide polyamine epichlorohydrin resin were added to the absolute dry weight of pulp. The mixture was stirred and dispersed. The pulp slurry having the above composition is made into paper by a fourdrinier machine, passed through a drier, a size press, and a machine calender, and has a basis weight of 180 g / m ² and a tension of 1.0.
A paper substrate (support B) of g / cm ³ was produced. The size press solution used in the size press step was prepared by mixing carboxyl-modified polyvinyl alcohol and sodium chloride in a weight ratio of 2: 1, adding the mixture to water, and heating and dissolving the mixture.
% On both sides of the paper.
The support B was obtained by applying 5 cc.

[Support C] A polyolefin resin composition (1) having the following composition (surface resin) was subjected to corona discharge treatment on both surfaces of the support B, and then mixed and dispersed on the surface (felt surface) with a Banbury mixer. The composition is applied using a melt extruder (melting temperature: 320 ° C.) having a T-shaped die, and coated so that the coating amount is 25 g / m ² , and on the back surface (wire surface), Polyolefin resin composition (2) (resin composition for back surface) having the following composition was applied in the same manner as described above so that the coating amount was 20 g / m ² , the felt side was mirror-finished with a cooling roll, and the wire side was It was cooled and solidified by a rough cooling roll.

Next, after a corona discharge treatment was performed on the surface coating layer surface, an anchor layer having the following composition was dried at 0.3 g by dry weight.
/ M ² with a gravure coater. The obtained support C had a surface smoothness (Oken type, J.TAP)
PI No. 5) was 6000 seconds, and its opacity (JIS P8138) was 93%.

Polyolefin resin composition (1) Long chain type low density polyethylene resin (density 0.926 g / cm
³ , melt index 20 g / 10 min) 35 parts, low density polyethylene resin (density 0.919 g / cm ³ , melt index 2 g / 10 min) 50 parts, anatase type titanium dioxide (A-220; manufactured by Ishihara Sangyo) 15 parts , Zinc stearate 0.1 part, antioxidant (Irganox 101
0; Ciba-Geigy) 0.03 parts, ultramarine (blue mouth ultramarine N)
o. 2000; manufactured by Daiichi Kasei Co., Ltd .; 0.09 part; optical brightener (UVITEX OB; manufactured by Ciba Geigy) 0.3 part Polyolefin resin composition (2) High-density polyethylene resin (density 0.954 g / cm ³ , melt index 20 g) / 10 minutes) 65 parts, low-density polyethylene resin (density 0.924 g / cm ³ , melt index 4 g / 10 minutes) 35 parts Anchor layer gelatin (manufactured by Nitta Gelatin, trademark: G0282K) 10
0 parts, surfactant Kao, trademark: Emar E27C)
0.005 parts

Preparation of Fine Pigment [Fine Pigment A] Commercially available precipitated silica (trade name: Fine Seal X-45, manufactured by Tokuyama Co., Ltd., average primary particle diameter: about 1)
0 nm, average secondary particle diameter: about 4.5 μm) is dispersed in water by a sand grinder and then pulverized and dispersed using a Nanomizer (trade name: Nanomizer), and the average secondary particle diameter is repeated. Is 80nm
To prepare a 12% dispersion A containing fine particles of

[Fine pigment A1] Commercially available precipitated silica (trade name: Fine Seal X-45, manufactured by Tokuyama Corporation, average primary particle diameter: about 10 nm, average secondary particle diameter: about 4.5 μm) is dispersed in water by a sand grinder. After pulverization, the process of pulverizing and dispersing was further repeated using a Nanomizer (manufactured by Nanomizer Co., Ltd., trade name: Nanomizer) to prepare a 12% dispersion containing particles having an average secondary particle diameter of 50 nm. To this dispersion, 10 parts of a cationic resin (Sumitomo Chemical Co., Ltd., trade name: Sumiretz Resin # 1001) was added to cause aggregation of the pigment and thickening of the dispersion. This dispersion liquid is again subjected to a pulverizing and dispersing step using a Nanomizer to obtain particles containing particles having an average secondary particle diameter (aggregated particle diameter) of 100 nm.
% Dispersion A1 was prepared.

[Fine pigment A2] Commercially available precipitated silica (trade name: Fine Seal X-45, manufactured by Tokuyama Corporation, average primary particle diameter: about 10 nm, average secondary particle diameter: about 4.5 μm) is dispersed in water by a sand grinder. This was pulverized to prepare a 12% dispersion containing particles having an average secondary particle diameter of 1 μm. To this dispersion, 10 parts of a cationic resin (Sumitomo Chemical Co., Ltd., trade name: Sumiretz Resin # 1001) was added to cause aggregation of the pigment and thickening of the dispersion. Again, this dispersion is repeatedly subjected to a pulverizing and dispersing step using a sand grinder,
A 10% dispersion A2 containing particles having an average secondary particle diameter (aggregated particle diameter) of 1.0 μm was prepared. [Fine pigment A3] Commercially available precipitated silica (trade name: Fine Seal X-45, manufactured by Tokuyama Corporation), average primary particle diameter: about 1
0 nm, average secondary particle diameter: about 4.5 μm) was dispersed and pulverized in water by a sand grinder, and then pulverized and dispersed using a nanomizer. After dispersion, the average secondary particle diameter was 80 nm.
Was prepared. To the dispersion was added 10 parts of diallyldimethyl quaternary ammonium hydrochloride (trade name: Unisense CP-103, manufactured by SENKA CORPORATION) as a cationic resin to cause aggregation of the pigment and thickening of the dispersion. Pulverization and dispersion were repeated using a Nanomizer again to prepare an 8% dispersion A3 having an average secondary particle diameter (aggregated particle diameter) of 250 nm.

[Fine Pigment B] Commercially available gel silica (trade name: Silojet P612, manufactured by Grace Devison, average primary particle diameter: about 10 nm, average secondary particle diameter: about 7.5 μm)
m) was dispersed in water with a sand grinder, and then the process of further pulverizing and dispersing using a Nanomizer (trade name: Nanomizer) was repeated to obtain a 15% dispersion B containing particles having an average secondary particle diameter of 300 nm. Prepared.

[Fine pigment C1] Commercial fumed silica (trade name: Leolosil QS-3, manufactured by Tokuyama Corporation)
0, specific surface area 300 m ² / g, average primary particle diameter: about 10
was dispersed in water using a sand grinder, and then the process of pulverizing and dispersing using a nanomizer was repeated to prepare a 12% dispersion containing particles having an average secondary particle diameter of 80 nm. To this dispersion, 10 parts of a cationic resin (Sumitomo Chemical Co., Ltd., trade name: Sumiretz Resin # 1001) was added to cause aggregation of the pigment and thickening of the dispersion. Again, this dispersion was repeatedly subjected to a pulverizing and dispersing step using a Nanomizer to prepare a 10% dispersion C1 containing particles having an average secondary particle diameter (aggregated particle diameter) of 100 nm. [Fine pigment C2] Commercial fumed silica (manufactured by Tokuyama Co., Ltd., trademark: Reolosil QS-30, specific surface area 300 m)
² / g, average primary particle diameter: about 10 nm) by water dispersion and pulverization with a sand grinder, and then pulverized and dispersed using a Nanomizer (manufactured by Nanomizer Co., Ltd.). A liquid was prepared. Diallyldimethyl quaternary ammonium hydrochloride (manufactured by SENKA, trademark: Unisense CP-1) is used as a cationic resin in the dispersion.
03) 10 parts were added to cause aggregation of the pigment and thickening of the dispersion. Pulverization and dispersion were repeated again using a Nanomizer to prepare an 8% dispersion C2 having an average secondary particle diameter (aggregated particle diameter) of 250 nm.

[Fine Pigment D] Commercially available alumina (manufactured by Sumitomo Chemical Co., Ltd., trade name: AKP-G015, γ crystal form, average secondary particle diameter: about 2 μm) was water-dispersed and pulverized by a sand grinder, and then the Nanomizer was removed. And containing the particles having an average secondary particle diameter of 130 nm.
A 0% dispersion D was prepared.

Example 1 The following coating solution (1) was coated on a support B by a die coater so that the coating amount was 5 g / m ^2, and dried to produce an ink jet recording body of the present invention. did.

[Coating liquid (1)] 2100 parts of fine pigment C
Silyl-modified polyvinyl alcohol (Kuraray Co., Ltd., trademark:
PVA R-1130) 35 parts, pyrocatechol-3,
An aqueous coating solution prepared by mixing 5 parts of sodium 5-disulfonate (manufactured by Kanto Chemical Co., Ltd., also known as Tyrone, hereinafter referred to as Tyrone) to a concentration of 8%.

Example 2 Before providing the ink receiving layer comprising the coating liquid (1) of Example 1, the following coating liquid (2) was applied to the support B at a coating amount of 15 g /
It was applied by a die coater so as to obtain m ² and dried. Next, the coating liquid (1) was applied in the same coating amount as in Example 1, and dried to produce an ink jet recording body of the present invention.

[Coating liquid (2)] Gel method silica (trade name: Silojet P403, manufactured by Grace Devison, average primary particle diameter: about 13 nm, average secondary particle diameter: 3 μm) 10
0 parts are silyl-modified polyvinyl alcohol (Kuraray Co., Ltd.
(Trademark: PVA R-1130) 35 parts
Aqueous coating liquid adjusted to 5%.

Example 3 An ink jet recording material of the present invention was produced in the same manner as in Example 2 except that the support B was changed to the support C.

Example 4 PET film (trade name: Lumilar T50μ, manufactured by Toray Industries, Inc.)
m), a coating liquid obtained by changing the sodium pyrocatechol-3,5-disulfonate of the coating liquid (1) to sodium salicylate (manufactured by Kanto Chemical Co., Ltd.) so that the coating amount becomes 5 g / m ^2. Coated and dried. Next, the coating liquid (2) was coated with a die coater so that the coating amount was 15 g / m ^2, and dried to obtain an ink jet recording layer. Next, the coating liquid (2) was applied onto the support B, and the coating amount was 1
Coating was performed with a bar coater so as to obtain 0 g / m ² , the coated surface and the coated surface of the ink jet recording layer were bonded, dried, and the PET film was peeled off to produce an ink jet recording body of the present invention.

Example 5 An ink jet recording medium of the present invention was produced in the same manner as in Example 3 except that 3 parts of calcium chloride (manufactured by Kanto Chemical Co., Ltd.) was added to the coating solution (1).

Example 6 In Example 3, the following coating liquid (3) was used instead of the coating liquid (2), and the following coating liquid (4) was used instead of the coating liquid (1). An ink jet recording medium was manufactured.

[Coating liquid (3)] Gel silica (trade name: Silojet 703A, manufactured by Grace Devison, average primary particle diameter: about 10 to 15 nm, average secondary particle diameter: 300 n)
m) An aqueous coating solution prepared by mixing 100 parts, 25 parts of polyvinyl alcohol (manufactured by Kuraray Co., trade name: PVA-140H) and 10 parts of sodium p-hydroxybenzenesulfonate (manufactured by Kanto Chemical) to adjust the concentration to 15%.

[Coating liquid (4)] 2100 parts of fine pigment C
Silyl-modified polyvinyl alcohol (Kuraray Co., Ltd., trademark:
An aqueous coating solution prepared by mixing 35 parts of PVA R-1130) and 7 parts of sodium p-hydroxybenzenesulfonate (manufactured by Kanto Chemical Co.) to adjust the concentration to 8%.

Example 7 The gel silica of the coating liquid (3) was changed to an alumina-modified gel silica (trade name: WSSG-1CA, manufactured by Grace Devison).
An ink jet recording medium was manufactured in the same manner as in Example 6, except that the average secondary particle diameter was changed to 1 μm.

Example 8 The support C was changed to polypropylene synthetic paper (trade name: GWG-140, manufactured by Oji Yuka Co., Ltd.), and the coating liquids (3) and (4) were used.
Sodium p-hydroxybenzenesulfonate 10
An ink jet recording medium was manufactured in the same manner as in Example 6, except that the part was changed to 15 parts of arbutin (manufactured by Tokyo Chemical Industry Co., Ltd.).

Comparative Example 1 An ink jet recording material was manufactured in the same manner as in Example 3 except that Tyrone was omitted.

Comparative Example 2 An ink jet recording material was manufactured in the same manner as in Example 3 except that the fine pigment C2 was changed to the fine pigment A3.

Comparative Example 3 An ink jet recording material was manufactured in the same manner as in Example 3, except that Tyrone was changed to a benzotriazole-based ultraviolet absorber (trade name: JF-77, manufactured by Johoku Chemical Co., Ltd.).

Comparative Example 4 Except that Tyrone was changed to a hindered amine light stabilizer (trade name: Tinuvin 144, manufactured by Ciba Geigy),
Other than that produced the inkjet recording body like Example 3. FIG.

Comparative Example 5 Except that the average secondary particle diameter was adjusted to 700 nm by pulverization and dispersion after the addition of the cationic resin in the preparation of the fine pigment C2,
Other than that produced the inkjet recording body like Example 3. FIG.

[Evaluation Method] The ink absorbency, print density, print gloss, image light fastness and print water fastness of the ink jet recording materials obtained in each of the above Examples and Comparative Examples were evaluated by the following methods. . The printing was performed using an Epson printer (model: PM-770C).

[Ink Absorbency] A 10 × 10 cm ² square ink jet recording medium of the present invention was attached to the center of A4 size high quality paper, and black ink was solid printed so that the ink discharge amount was 15 g / m ^2. Then, observe how the ink overflows from the printing section. Actually, high quality paper was stuck to the printing portion, and the time until ink was not transferred at all was measured. ◎: less than 1 second ○: 1 second or more to less than 5 seconds Δ: 5 seconds or more to less than 1 minute ×: 1 minute or more

[Print Density] The print density of the solid black portion was measured using a Macbeth reflection densitometer (trade name: RD-9, manufactured by Macbeth).
14).

[Print Gloss] The gloss of the surface was visually evaluated from an angle of 20 degrees with respect to the recording surface. ：: High glossiness comparable to color photos. ：: Inferior to color photograph but high gloss. Δ: glossy X: Poor gloss.

[Image Lightfastness] Evaluation was performed using a commercially available ink jet printer (Model: PM-770, manufactured by Epson Corporation).
C) N1A and portrait of “High-definition color digital standard image data (ISO / JIS-SCID), published by the Japan Standards Association” were used as evaluation images. The printed matter obtained was subjected to a xenon lamp type FADE-O-METER.
(ATLAS ELECTRIC DEVICES C
o. (Model: CI35F, manufactured by Sharp Corp.), and was continuously treated for 50 hours at 63 ° C. and 50% relative humidity. The lightfastness level was evaluated as follows, compared to the untreated image. A: Almost no fading occurred. ：: Slightly faded, but usable level. Δ: Discolored, the color balance is lost, but usable level. X: Discolored, and the color balance was greatly lost. Unusable level.

[Water Resistance of Printed Area]
After leaving for a while, water droplets were dropped on the printed portion and wiped off one minute later. The state of the portion where the water droplet was dropped was visually observed. A: No ink bleeding. ：: Good, with only slight ink bleeding observed. Δ: Bleed of ink, but practically endurable. X: There is bleeding of the ink, and there is a practical problem.

[0111]

[Table 1]

As is clear from the results shown in Table 1, the recording materials of Examples 1 to 8 containing fumed silica having an average secondary particle diameter of 300 nm or less and a phenolic compound had high print density and gloss. Further, the image light resistance was good. In particular, in Examples 2 to 8 in which two or more recording layers were provided, the absorption was good and the image quality was excellent. Examples 1 to 3, 5 to 8 in which a hydroquinone derivative, a pyrocatechol derivative, and a phenol sulfonate were selected as the phenolic compound were particularly excellent in light resistance. On the other hand, Comparative Example 1 containing no lightfastness improver, Comparative Example 3 containing a general ultraviolet absorber, and Comparative Example 4 containing a light stabilizer have light resistance and do not use fumed silica. In Comparative Example 2 and Comparative Example 5 in which the average secondary particle size of the fumed silica was more than 300 nm, the print density and glossiness were remarkably inferior, and the desired recording medium could not be obtained.

Comparative Example 6 The undercoat layer coating solution having the following composition was applied on the surface of the support C using a die coater so that the dry weight was 20 g / m ² , and dried. Next, the following outermost layer coating solution,
On the above-mentioned undercoat layer, it applied and dried using a die coater so that dry weight might be set to 6 g / m < ² >.

Undercoat layer coating liquid (solid content 12%) 100 parts of silica fine pigment B Polyvinyl alcohol (trade name: PVA135; manufactured by Kuraray) 17 parts Coating liquid for outermost layer (solid content 10%) ) silica fine pigment C1 100 parts polyvinyl alcohol (trademark: PVA135; manufactured by Kuraray) 15 parts

[0115] In each of Examples 9-12 Examples 9-12 were prepared ink jet recording material in the same manner as in Comparative Example 6. However, on the outermost layer, a 4% aqueous solution of boric acid was applied with a solids adhesion weight of 0.2%.
The composition was applied using a bar coater to a concentration of 5, 0.5, 1.0, or 5.0 g / m ² and dried.

Example 13 An ink jet recording medium was prepared in the same manner as in Comparative Example 6. However, the outermost layer was formed using a coating solution for the outermost layer having the following composition. Coating solution for outermost layer (solid content 7%)・ 100 parts of silica fine pigment C ・ 15 parts of polyvinyl alcohol (trade name: PVA135; manufactured by Kuraray) ・ 0.25 part of boric acid

Example 14 An ink jet recording medium was produced in the same manner as in Comparative Example 6. However, on the outermost layer, a 4% aqueous solution of borax (sodium tetraborate + hydrate) was applied with a solids adhesion weight of 0.1%.
Coating was carried out using a bar coater to a concentration of 5 g / m ² and dried.

[0118] In each of Examples 15-18 Example 15-18 were prepared ink jet recording material in the same manner as in Comparative Example 6. However, on the outermost layer, a 10% aqueous solution of γ-cyclodextrin was applied with a solid content of 0.25, 0.5, 1.0, or 5.0.
g / m ² using a bar coater.
Dried.

Example 19 An ink jet recording medium was produced in the same manner as in Comparative Example 6. However, the outermost layer was formed using a coating solution for the uppermost layer having the following composition. Coating solution for outermost layer (solid content 10%) 100 parts of silica fine pigment C 15 parts of polyvinyl alcohol (trademark: PVA135; manufactured by Kuraray) 1.0 part of γ-cyclodextrin

Example 20 A 1% aqueous solution of β-cyclodextrin was placed on the outermost layer of the ink jet recording material prepared in Comparative Example 6 by using a bar coder so that the solid adhesion weight was 0.25 g / m ^2. And dried.

Comparative Example 7 On the surface of the support A, a coating solution for an undercoat layer having the following composition was
Coating and drying were performed with an air knife coater so that the weight of the solid content was 10 g / m ² . Next, the following coating liquid for an undercoat upper layer is applied onto the above-mentioned undercoat lower layer so that the solid content weight is 5%.
g / m ² was applied with an air knife coater and dried. Next, a coating liquid for the outermost layer having the following composition was applied using a roll coater, immediately pressed against a mirror-surface drum having a surface temperature of 95 ° C., dried, and released to obtain a glossy inkjet recording material. . The coating amount of the outermost layer at this time was 3 g / m ² in terms of solid content weight.

Undercoat Coating solution for underlayer (solid content : 15%) Synthetic silica (trade name: Fine Seal X-60; manufactured by Tokuyama, average secondary particle diameter 6.0 μm, average primary particle diameter 15)
nm) 70 parts ・ Zeolite (trademark: Toyobuilder; manufactured by Tosoh, average particle size 1.5 μm) 30 parts ・ Silyl-modified polyvinyl alcohol (trademark: R113)
0; manufactured by Kuraray Co.) 20 parts undercoat layer coating solution (solid concentration 12%) silica fine pigment A 100 parts Polyvinyl alcohol (trademark: PVA117; manufactured by Kuraray) 15 parts of the outermost layer coating solution (solid content Concentration: 12%) -100 parts of silica fine pigment A-25 parts of polyvinyl alcohol (trademark: PVA117; manufactured by Kuraray)-2 parts of stearamide

Example 21 A 4% aqueous solution of boric acid was applied on the outermost layer of the ink-jet recording material obtained in Comparative Example 7 with a bar coater so that the solid adhesion weight was 1.0 g / m ^2. Coating,
Dried.

Example 22 A 10% aqueous solution of γ-cyclodextrin was applied on the outermost layer of the ink jet recording material obtained in Comparative Example 7.
Coating was carried out with a bar coater so that the weight of solids attached was 1.0 g / m ² and dried.

Comparative Example 8 A coating solution for an undercoat layer having the following composition was applied on the surface of the support A with an air knife coater so that the dry adhesion weight was 12 g / m ² , and dried. Next, a coating solution for the outermost layer having the following composition is applied on the undercoat layer with an air knife coater, dried with cold air for 20 seconds, and then placed in a semi-dry state. To a mirror drum having a surface temperature of 100 ° C., dried and released from the mold to obtain a glossy inkjet recording material. At this time, the coating weight of the solid content in the coating amount of the outermost layer was 6 g / m ² .

Coating solution for undercoat layer (solid content : 15%) / Synthetic silica (trade name: Fine Seal X-60; manufactured by Tokuyama, average secondary particle diameter 6.0 μm, average primary particle diameter 15)
nm) 70 parts ・ Zeolite (trademark: Toyobuilder; manufactured by Tosoh, average particle size 1.5 μm) 30 parts ・ Silyl-modified polyvinyl alcohol (trademark: R113)
0; Kuraray Co., Ltd.) 20 parts Coating liquid for outermost layer (solid content: 12%)・ Silica fine pigment A1 100 parts ・ Polyvinyl alcohol (trade name: PVA117; Kuraray Co.) 15 parts ・ Stearic acid amide 2 parts

Example 23 A 4% aqueous solution of boric acid was coated on the outermost layer of the ink jet recording medium of Comparative Example 8 with a bar coater so that the solid adhesion weight was 1.0 g / m ^2. And dried.

Example 24 On the outermost layer of the ink jet recording medium of Comparative Example 8, γ-
A 10% aqueous solution of cyclodextrin was coated with a bar coater and dried so that the weight of solids attached was 1.0 g / m ² .

Comparative Example 9 A coating liquid having the following composition was coated on a surface of a PET film (trade name: Lumirror T50 μm, manufactured by Toray Industries, Inc.) to be used as a molding surface so that the solid adhesion weight was 5 g / m ^2. Then, a coating liquid having the following composition was applied on the coating layer by a die coder so that the solid content adhesion weight was 10 g / m ² . Next, on the surface of the support B, the coating liquid was applied with a solid content of 2 g.
/ M ² with a bar coater, which was adhered to the above-mentioned coated surface of the PET film and dried, and then the PET film was peeled off to produce an ink jet recording medium.

[0130] coating solution (solid concentration 12%) silica fine pigment B 100 parts Polyvinyl alcohol (trademark: PVA135; manufactured by Kuraray) 17 parts Coating Liquid (solid content of 10%) silica fine pigment A1 100 parts・ 15 parts of polyvinyl alcohol (trademark: PVA135; manufactured by Kuraray)

Example 25 An ink jet recording medium was produced in the same manner as in Comparative Example 9. However, after coating and drying the coating liquid on the PET film, a 4% aqueous solution of boric acid was applied on the coating layer of the coating liquid so that the solid adhesion weight became 1.0 g / m ² . Coating was performed with a bar coater, and immediately (before drying), the coating solution was coated and dried with a die coater.

Example 26 An ink jet recording medium was produced in the same manner as in Comparative Example 9. However, after coating and drying the coating liquid on the PET film, a 10% aqueous solution of γ-cyclodextrin is applied on the coating layer of the coating liquid to a solid content of 1.0 g / m ² . As described above, the coating solution was applied by a bar coater, immediately (before drying), and the coating solution was applied and dried by a die coater.

Comparative Example 10 An undercoat layer was formed by applying a coating solution having the following composition on the surface of the support A with an air knife coater so that the dry weight was 10 g / m ² . Coating solution (solid content 18%) / Synthetic silica (trade name: Fine Seal X-60; manufactured by Tokuyama, average secondary particle diameter 6.0 μm, average primary particle diameter 15)
nm) 100 parts ・ Silica-modified polyvinyl alcohol (trademark: R113)
0; manufactured by Kuraray Co., Ltd.) 20 parts ・ Cationic resin (manufactured by Senka Co., Ltd., trademark: CP10)
3) 15 parts ・ Cationic resin (Nikafix E117, manufactured by Nichika Chemical Co., Ltd.) 5 parts

Next, a coating solution having the following composition was applied onto the above-mentioned undercoat layer using a roll coater, and immediately (before drying) the coating layer was applied to a mirror surface having a surface temperature of 85 ° C. After being pressed against the drum and dried, the formed outermost layer was released from the mold to obtain a gloss type ink jet recording medium. At this time, the coating layer of the gloss outermost layer had a solid content of 8 g / m ² . Coating liquid (solid content 25%) / styrene-2-methylhexyl acrylate copolymer emulsion having a glass transition point of 75 ° C (average particle diameter 40n)
m) 30 parts ・ Colloidal silica (average particle diameter 30 nm) 70 parts ・ Thickening / dispersing agent (alkyl vinyl ether / maleic acid derivative copolymer) 5 parts ・ Release agent (lecithin) 1.5 parts

Example 27 A 4% aqueous solution of boric acid was coated on the outermost layer of the ink jet recording medium of Comparative Example 8 with a bar coater so that the solid adhesion weight was 1.0 g / m ^2. And dried.

Example 28 On the outermost layer of the ink jet recording medium of Comparative Example 8, γ-
A 10% aqueous solution of cyclodextrin was coated with a bar coater and dried so that the weight of solids attached was 1.0 g / m ² .

Example 29 On a support C, an undercoat layer coating solution having the following composition was applied by a die coater so that the dry adhesion weight was 20 g / m ² , and dried. Next, the outermost layer coating liquid having the following composition was applied on the undercoat layer by a die coater to a dry adhesion weight of 6 g / m 2.
Coating and drying were performed to obtain ² . Then, on the outermost layer, a 4% aqueous solution of boric acid was applied to the solid content weight of 1.0 g.
/ M ² and coated with a bar coater and dried.

Coating solution for undercoat layer (solid content: 12%) , 100 parts of silica fine pigment B, 17 parts of polyvinyl alcohol (trade name: PVA135; manufactured by Kuraray) Coating solution for outermost layer (solid content: 10%) ) alumina fine pigment D 100 parts polyvinyl alcohol (trademark: PVA135; manufactured by Kuraray) 15 parts

Example 30 An ink jet recording medium was produced in the same manner as in Example 29. However, instead of the boric acid aqueous solution, a 10% aqueous solution of γ-cyclodextrin was used.
It was coated with a bar coater so as to obtain m ² and dried.

Example 31 An ink jet recording medium was produced in the same manner as in Example 29. However, in the coating liquid for the outermost layer, silica fine pigment A1 was used instead of alumina fine pigment D.

Example 32 An ink jet recording medium was prepared in the same manner as in Example 30. However, in the coating liquid for the outermost layer, silica fine pigment A1 was used instead of alumina fine pigment D.

Example 33 An ink jet recording medium was produced in the same manner as in Example 29. However, in the coating liquid for the outermost layer, silica fine pigment A2 was used instead of alumina fine pigment D.

Example 34 An ink jet recording medium was produced in the same manner as in Example 30. However, in the coating liquid for the outermost layer, silica fine pigment A2 was used instead of alumina fine pigment D.

Comparative Example 11 A coating liquid having the following composition was applied on the surface of the support A with an air knife coater so that the dry adhesion weight was 10 g / m ² , and dried to produce an ink jet recording medium. . Coating liquid (solid content 18%) , synthetic silica (Fine Seal X-60; manufactured by Tokuyama,
Average secondary particle diameter 6.0 μm, average primary particle diameter 15 nm) 1
00 parts Silyl-modified polyvinyl alcohol (trademark: R113)
0; manufactured by Kuraray Co., Ltd.) 20 parts ・ Cationic resin (manufactured by Senka Co., Ltd., trademark: CP10)
3) 15 parts ・ Cationic resin (Nikafix E117, manufactured by Nichika Chemical Co., Ltd.) 5 parts

Comparative Example 12 Support B was used as it was as an ink jet recording medium.

The quality of the ink jet recording papers produced in Examples 9 to 34 and Comparative Examples 6 to 12 was evaluated by the following method.

(Evaluation Method) The image light fastness, print density and image water fastness of the ink jet recording materials obtained in Examples and Comparative Examples were evaluated by the following methods. In addition, a printer manufactured by Epson (model: PM-750C) was used for printing. A printer (Model: DJ970Cxi) manufactured by Hewlett-Packard Company was also used for the light resistance evaluation.

[Image Lightfastness] Images of ISO-400 (“High-definition color digital standard image data ISO / J
IS-SCID ", p13, Image name: fruit basket, p1
4. Image name: Candle, printed by the Japan Standards Association, in glossy paper mode (the printer and use), and the obtained two print samples are xenon lamp type FADE-O-METER (ATLAS ELECTR).
IC DEVICES Co. Company, Model: C135
F) was used for a light resistance test at 63 ° C., 50% for 50 hours. Compare the two images with the unprocessed image,
The light resistance level was evaluated in the following eight classes. A: Almost no fading occurred. −-: intermediate level between ◎ and ○. : Slightly faded, but usable level. −-: intermediate level between ○ and △. Δ: Discolored and the color balance is lost, but barely usable. Δ−: intermediate level between Δ and ×. ×: The level is unusable because of fading, color balance is greatly lost. XX: The degree of fading is remarkable.

[Uniformity of solid printing portion]
A solid printing portion of a mixture of two colors of a cyan ink and a magenta ink was formed, and the printing unevenness (shading unevenness) was visually observed as follows.
Class rated. A: Very good level without any print unevenness. ：: Good level with almost no uneven printing. −-: A level at which there is some printing unevenness, but there is almost no problem in practical use. Δ: A level at which printing unevenness is slight and is a little problematic in practical use. ×: A level at which printing unevenness is large and poses a practical problem.

[Print bleeding] Using the above, black
Solid printing portions of cyan, magenta, and yellow inks were printed so that their borders were in contact with each other, and bleeding at the borders was visually evaluated according to the following five classes. ◎: Very good level without any bleeding. : Good level with almost no bleeding. −-: There is slight bleeding, but there is almost no problem in practical use. Δ: Bleeding is slightly noticeable, and is a level that is somewhat problematic in practical use. ×: A level at which bleeding is conspicuous and poses a practical problem.

[Print Density] The print density of the black solid portion printed as described above was measured using a Macbeth reflection densitometer (Macbeth,
Model: RD-920). The numbers shown in the table are the average values of three measurements.

[Water resistance to printing] After printing on the ink jet recording medium, after leaving it for 24 hours, a water drop was dropped thereon. One minute later, the water drop was wiped off, and the condition of the portion immersed in the water drop was observed. Evaluation was made in four classes. A: Almost no ink was removed. ：: A level at which a small amount of ink was removed but no problem occurred in practical use. −-: A level at which a part of the ink was removed but practically no problem occurred. ×: A level at which color discoloration of the ink is large and poses a practical problem.

[Blank gloss] The 75 ° gloss of a blank portion was measured according to JIS-P8142.

The test results are shown in Tables 2 and 3.

[0155]

[Table 2]

[0156]

[Table 3]

As is clear from Tables 2 and 3, the ink image formed on the ink jet recording medium of the present invention has good light fastness, and its image color density, uniformity, bleeding fastness and water fastness. The properties were also satisfactory.

[0158]

The ink-jet recording medium of the present invention also satisfies other image performances which can significantly improve the light fastness of the ink image recorded thereon. Therefore, the ink jet recording medium of the present invention has high practicality.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazuaki Oshima 1-10-6 Shinonome, Koto-ku, Tokyo Oji Paper Co., Ltd. Shinonome Research Center (72) Inventor Shun-ichiro Mukoyoshi 1-10, Shinonome, Koto-ku, Tokyo No. 6 Oji Paper Co., Ltd. Shinonome Research Center (72) Inventor Tetsuo Tsuchida 4-3-1 Jokoji, Amagasaki-shi, Hyogo Prefecture Oji Paper Co., Ltd. Amagasaki Research Center F-term (reference) 2H086 BA15 BA31 BA33 BA34 BA35 BA38 BA41 BA45

Claims (15)

[Claims] 1. An ink receiving layer comprising: a substrate; and an ink receiving layer formed on at least one surface of the substrate, wherein the ink receiving layer includes fine pigment particles having an average particle diameter of 1 μm or less and a binder. And an image recording medium comprising at least one kind of an image lightfastness improver selected from a phenolic compound, boric acid, a borate and a cyclodextrin compound. 2. A method according to claim 1, further comprising: a base material; and a composite ink receiving layer formed on at least one surface of the base material and comprising a plurality of ink receiving layers stacked on each other. An outermost outermost ink receiving layer includes fine pigment particles of 1 μm or less and a binder, and at least one of the plurality of ink receiving layers includes a phenolic compound, boric acid, borate, and cycloalkyl. An ink jet recording material comprising: an image lightfastness improver comprising at least one selected from dextrins. 3. The fine pigment particles comprise an aggregate of a plurality of primary particles having an average primary particle diameter of 3 to 40 nm,
3. The ink jet recording medium according to claim 1, wherein the ink jet recording medium has a shape of secondary particles having an average secondary particle diameter of 1 μm or less. 4. The ink jet recording material according to claim 1, wherein the phenol compound is selected from a hydroquinone compound, a pyrocatechol compound, and a phenolsulfonic acid compound. 5. The method according to claim 1, wherein the cyclodextrin compound is α-
The inkjet recording material according to claim 1, wherein the inkjet recording material is selected from cyclodextrin, β-cyclodextrin, γ-cyclodextrin, alkylated cyclodextrin, hydroxyalkylated cyclodextrin, and cation-modified cyclodextrin. 6. The method according to claim 1, wherein the cyclodextrin compound is γ-
3. The ink jet recording material according to claim 1, which is a cyclodextrin. 7. The ink jet recording according to claim 1, wherein the image lightfastness improver is contained in the ink receiving layer by applying a solution thereof on the ink receiving layer and drying the solution. body. 8. The method according to claim 1, wherein the content of the image light fastness improver is 0.
The ink jet recording material according to claim 1, wherein the weight is 1 to 10 g / m ² . 9. The ink jet recording medium according to claim 1, wherein the fine pigment particles are at least one kind of fine particles selected from fumed silica, amorphous silica, alumina, and alumina hydrate. . 10. The method according to claim 10, wherein the fumed silica particles have a particle size of 3 to 5.
10. The ink jet recording material according to claim 9, comprising an aggregate of a plurality of primary particles having an average primary particle size of 0 nm, and having an average secondary particle size of 300 nm or less. 11. The ink jet recording medium according to claim 1, wherein the ink receiving layer containing the fine pigment particles and the binder further contains a cationic organic compound. 12. The method according to claim 12, wherein the binder is a water-soluble polymer compound,
3. The composition according to claim 1, further comprising at least one selected from the group consisting of a latex of a copolymer of a conjugated diene compound, a latex of a vinyl copolymer, a water-dispersible acrylic resin, a water-dispersible polyester resin, and a water-dispersible polyurethane resin. 3. The ink jet recording material according to item 1. 13. The method according to claim 1, wherein the binder is at least one selected from polyvinyl alcohol, partially saponified polyvinyl alcohol, acetoacetylated polyvinyl alcohol, silyl-modified polyvinyl alcohol, cation-modified polyvinyl alcohol, and anion-modified polyvinyl alcohol.
The inkjet recording material according to claim 1, comprising a seed. 14. The ink jet recording medium according to claim 1, wherein the substrate is made of a non-ink-absorbing material. 15. The ink jet recording medium according to claim 1, wherein the surface of the ink receiving layer has a surface glossiness of 75 ° of 30% or more.