JP2010064280A - Inkjet recording medium and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording medium which has excellent suitability for high speed air dry, can enhance glossiness of the printed image, and can reduce brashiness and overlapped unevenness, and to provide a method for manufacturing the same. <P>SOLUTION: The inkjet recording medium includes, on its nonabsorbent support body, in sequence from the support body: a first ink receiving layer (a first layer) containing silica formed by a gas phase method, a polyvinyl alcohol with a saponification of 90 mol% or higher (specified PVA), a boron composition, a water soluble zirconium salt (Zr salt): a second ink receiving layer (a second layer) containing silica formed by a gas phase method, a specified PVA, a boron compound and a water soluble organic solvent (a specified solvent) whose boiling point is 120°C or higher. The content of Zr salt in the second layer is less than that in the first layer and is 0.6 mass% or less with respect to the content of silica formed by the air phase method. The content of the specified organic solvent in the first layer is less than that in the second layer and 2% by mass or less with respect to the content of silica formed by the air phase method. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

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

In addition, with the recent increase in resolution of inkjet printers and the development of hardware (devices), various types of inkjet recording media have been developed, and in recent years it has become possible to obtain so-called photographic-like high-quality recorded matter. .
In particular, the characteristics required for ink jet recording media generally include (1) fast drying (high ink absorption speed), and (2) proper and uniform ink dot diameter (similar to (3) Good granularity, (4) High dot roundness, (5) High color density, (6) High saturation (no blurring) (7) The light resistance, gas resistance and water resistance of the printed part are good, (8) the whiteness of the recording surface is high, and (9) the preservability of the recording medium is good (yellow during long-term storage). No discoloration, image does not bleed after long-term storage), (10) good deformation and good dimensional stability (curl is sufficiently small), and (11) good hard running performance. Etc. In addition to the above properties, glossy paper, surface smoothness, and photographic paper-like texture similar to silver salt photography are also required for photo glossy paper used for the purpose of obtaining so-called photo-like high-quality recorded material. Is done.

Various ink jet recording media that satisfy the above requirements have been disclosed.
For example, it contains inorganic fine particles and a binder on a non-water-absorbing support for the purpose of providing an ink jet recording paper having excellent bleeding resistance during print storage with respect to a water-soluble dye without deteriorating bronzing. An ink jet recording sheet having a porous layer as an ink receiving layer is disclosed (for example, see Patent Document 1), in which the ink receiving layer contains a polyvalent metal compound and a water-soluble humectant.

Further, for the purpose of high printing density, high gloss, and excellent ink absorbability, inorganic fine particles, a water-soluble aluminum compound, a zirconium compound, a cation-modified self-emulsifying polymer, and a saponification degree of 92 are provided on a support. An ink jet recording medium having an ink receiving layer containing ˜98 mol% of polyvinyl alcohol and a crosslinking agent is disclosed, and the ink jet recording medium is produced by forming the ink receiving layer into two layers (for example, Patent Documents). 2).
JP 2003-312127 A JP 2007-223119 A

When two or more ink-receiving layers are provided on the support as shown in Patent Document 2, drying with high-speed air is indispensable for the purpose of improving the coating efficiency of the ink-receiving layer forming coating solution. Even if it dries with high-speed air after application | coating of this, the high-speed air drying suitability which does not produce a coating nonuniformity is calculated | required.
However, sufficient knowledge has not yet been obtained about improving glossiness and reducing brittleness while having the suitability for high-speed air drying.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an ink jet recording medium and a manufacturing method capable of improving glossiness of an image and reducing brittleness while having suitability for high-speed air drying. And

That is, the present invention
<1> A first ink containing vapor-phase-process silica, polyvinyl alcohol having a saponification degree of 90 mol% or more, a boron compound, and a water-soluble zirconium salt in this order from the non-absorbent support side. A second ink receiving layer comprising: a receiving layer; vapor phase method silica; polyvinyl alcohol having a saponification degree of 90 mol% or more; a boron compound; and a water-soluble organic solvent having a boiling point of 120 ° C. or higher, The content of the water-soluble zirconium salt in the second ink receiving layer is less than the content of the water-soluble zirconium salt in the first ink receiving layer, and the second ink receiving layer is water-soluble zirconium. When the salt is contained, the content of the water-soluble zirconium salt in the second ink receiving layer is 0.6% by mass or less with respect to the content of the vapor phase silica in the second ink receiving layer. And the content of the water-soluble organic solvent having a boiling point of 120 ° C. or higher in the first ink receiving layer is higher than the content of the water-soluble organic solvent having a boiling point of 120 ° C. or higher in the second ink receiving layer. When the first ink-receiving layer contains a water-soluble organic solvent having a boiling point of 120 ° C. or higher, the content of the water-soluble organic solvent having a boiling point of 120 ° C. or higher in the first ink-receiving layer is small. The inkjet recording medium is 2% by mass or less based on the content of vapor phase silica in the first ink receiving layer.

<2> The inkjet recording medium according to <1>, wherein the water-soluble organic solvent having a boiling point of 120 ° C. or higher is dialkylene glycol monoalkyl ether.

<3> The inkjet recording medium according to <1> or <2>, wherein the water-soluble organic solvent having a boiling point of 120 ° C. or higher is diethylene glycol monobutyl ether.

<4> The inkjet recording medium according to any one of <1> to <3>, further including a glossy layer containing colloidal silica at a position farthest from the non-absorbing support.

<5> On a non-absorbable support, a coating solution A containing vapor phase method silica, polyvinyl alcohol having a saponification degree of 90 mol% or more, a boron compound, and a water-soluble zirconium salt, vapor phase method silica, A coating liquid B containing polyvinyl alcohol having a saponification degree of 90 mol% or more, a boron compound, and a water-soluble organic solvent having a boiling point of 120 ° C. or higher is applied from the non-absorbable support side to the coating liquid A and the coating liquid B. A step of forming an ink receiving layer by simultaneous multilayer coating so as to be in order, wherein the content of the water-soluble zirconium salt in the coating liquid B is greater than the content of the water-soluble zirconium salt in the coating liquid A And when the coating liquid B contains a water-soluble zirconium salt, the content of the water-soluble zirconium salt in the coating liquid B is set to the content of the vapor phase silica in the coating liquid B. 0. The content of the water-soluble organic solvent having a boiling point in the coating liquid A of 120 ° C. or higher is less than the content of the water-soluble organic solvent having a boiling point in the coating liquid B of 120 ° C. or higher. When the coating liquid A contains a water-soluble organic solvent having a boiling point of 120 ° C. or higher, the content of the water-soluble organic solvent having a boiling point of 120 ° C. or higher in the coating liquid A is determined based on the content of the water in the coating liquid A. It is a manufacturing method of the inkjet recording medium which is 2 mass% or less with respect to content of a phase method silica.

<6> The coating solution B contains gas phase method silica dispersed by a high pressure disperser of 30 MPa to 300 MPa, and the coating solution A contains gas phase method silica dispersed using beads. It is a manufacturing method of an inkjet recording medium.

<7> The average secondary particle diameter of the silica fine particles of the vapor phase silica contained in the coating solution A is 100 nm to 170 nm, and the average secondary particles of the silica fine particles of the vapor phase silica contained in the coating solution B It is a manufacturing method of the inkjet recording medium as described in said <5> whose diameter is 80 nm-130 nm.

  ADVANTAGE OF THE INVENTION According to this invention, the inkjet recording medium which can improve the glossiness of an image and can reduce a brittleness can be provided, having a high-speed air drying suitability.

Hereinafter, the ink jet recording medium of the present invention, the production method thereof, and the ink jet recording method will be described in detail.
<Inkjet recording medium>
The ink jet recording medium of the present invention comprises, on a non-absorbent support, in order from the non-absorbent support side, vapor phase silica, polyvinyl alcohol having a saponification degree of 90 mol% or more, boric acid, and a water-soluble zirconium salt. A first ink receiving layer, a vapor phase method silica, a polyvinyl alcohol having a saponification degree of 90 mol% or more, boric acid, and a water-soluble organic solvent having a boiling point of 120 ° C. or more; Have
Here, the content of the water-soluble zirconium salt in the second ink receiving layer is less than the content of the water-soluble zirconium salt in the first ink receiving layer, and the second ink receiving layer. When the water-soluble zirconium salt contains a water-soluble zirconium salt, the content of the water-soluble zirconium salt in the second ink receiving layer is 0.6 relative to the content of the vapor phase silica in the second ink receiving layer. It is below mass%. Further, the content of the water-soluble organic solvent having a boiling point of 120 ° C. or higher in the first ink receiving layer is higher than the content of the water-soluble organic solvent having a boiling point of 120 ° C. or higher in the second ink receiving layer. When the first ink-receiving layer contains a water-soluble organic solvent having a boiling point of 120 ° C. or higher, the content of the water-soluble organic solvent having a boiling point of 120 ° C. or higher in the first ink-receiving layer is small. The content of the vapor phase silica in the first ink receiving layer is 2% by mass or less.

(Ink receiving layer)
The ink receiving layer of the ink jet recording medium of the present invention is provided on a non-absorbing support, and at least 2 provided with a first ink receiving layer and a second ink receiving layer in that order from the non-absorbing support side. Composed of layers.
In this specification, all the ink receiving layers in the inkjet recording medium of the present invention including the first ink receiving layer and the second ink receiving layer are simply referred to as “ink receiving layers”.

(Gas phase method silica)
The ink receiving layer according to the present invention contains vapor-phase-process silica in at least both the first ink receiving layer and the second ink receiving layer.
Since the silica fine particles have a particularly large specific surface area, the ink absorption and retention efficiency is high, and the refractive index is low. Therefore, if the dispersion is carried out to an appropriate fine particle diameter, the ink receiving layer can be provided with transparency and high. There is an advantage that color density and good color developability can be obtained. Thus, the fact that the receiving layer is transparent means that not only for applications that require transparency, such as OHP, but also when applied to recording sheets such as photo glossy paper, a high color density and good color developability and This is important from the viewpoint of obtaining glossiness.

Generally, silica fine particles are roughly classified into wet method particles and dry method (gas phase method) particles depending on the production method. In the above wet method, a method is mainly used in which activated silica is produced by acid decomposition of a silicate, and this is appropriately polymerized and agglomerated and precipitated to obtain hydrous silica. On the other hand, the gas phase method is a method by high-temperature gas phase hydrolysis of silicon halide (flame hydrolysis method), a method in which silica sand and coke are heated and reduced by an arc in an electric furnace and oxidized with air. The method of obtaining anhydrous silica by the (arc method) is the mainstream, and the “gas phase method silica” refers to anhydrous silica fine particles obtained by the gas phase method.
The ink receiving layer in the present invention needs to contain the latter silica fine particles, that is, vapor phase method silica.

Vapor phase method silica is different from the above hydrous silica in the density of silanol groups on the surface, the presence or absence of vacancies, etc., and shows different properties, but is suitable for forming a three-dimensional structure with high porosity. The reason for this is not clear, but in the case of hydrous silica, the density of silanol groups on the surface of the fine particles is as high as 5 to 8 / nm ^2, and the silica fine particles tend to aggregate (aggregate) easily, In the case of the method silica, the density of silanol groups on the surface of the fine particles is as small as ² to 3 / nm ² , so that it becomes sparse soft agglomeration (flocculate), and as a result, it is estimated that the structure has a high porosity. The
In the present invention, silica fine particles having a density of silanol groups on the surface of the vapor phase method silica fine particles of 2 to 3 / nm ² are preferable.

The average primary particle diameter of the silica fine particles of the vapor phase method silica is preferably 20 nm or less, more preferably 15 nm or less, and particularly preferably 10 nm or less. When the average primary particle diameter is 20 nm or less, the ink absorption characteristics can be effectively improved, and at the same time, the glossiness of the ink receiving layer surface can be enhanced.
In the present invention, the average primary particle diameter of the silica fine particles refers to a value measured using a scanning electron microscope (SEM).

Further, the BET specific surface area of the silica fine particles of the vapor-phase-method silica is preferably at least 200 meters ² / g, more preferably more than 250 meters ² / g, particularly preferably at least 300m ² / g.
When the specific surface area of the silica fine particles of the vapor-phase process silica is 200 or more m ² / g, the ink image-receiving layer is highly transparent and the printing density can be kept high.

  Silica fine particles have silanol groups on their surfaces, and the particles are likely to adhere to each other by hydrogen bonding of the silanol groups, and because of the adhesion effect between the silanol groups and the particles via the water-soluble resin, In addition, when the average primary particle diameter of the silica fine particles is 20 nm or less, the ink receiving layer has a high porosity and a highly transparent structure can be formed, and the ink absorption characteristics can be effectively improved.

  The BET method referred to in the present invention is one of powder surface area measurement methods by vapor phase adsorption, and is a method for determining the total surface area, that is, the specific surface area of a 1 g sample from the adsorption isotherm. Usually, nitrogen gas is often used as the adsorbed gas, and the method of measuring the adsorption amount from the change in pressure or volume of the gas to be adsorbed is most often used. The most prominent expression for expressing the isotherm of multimolecular adsorption is the Brunauer, Emmett, and Teller equation, called the BET equation, which is widely used for determining the surface area. The adsorption amount is obtained based on the BET equation, and the surface area is obtained by multiplying the area occupied by one adsorbed molecule on the surface.

The content of the vapor phase silica in the total ink receiving layer is preferably 50% by mass to 80%, and more preferably 60% by mass to 70% by mass with respect to the total solid mass of the total ink receiving layer. .
In the present invention, from the viewpoint of coating surface shape, overlap unevenness, and wet heat bleeding, the content of the vapor phase silica in the second ink receiving layer is 5% by mass of the silica content in the total ink receiving layer. It is preferable that it is -60 mass%. More preferably, it is 10% by mass to 50% by mass of the silica content in the total ink receiving layer, and more preferably 15% by mass to 30% by mass.

-Inorganic fine particles-
The ink receiving layer according to the present invention may contain inorganic fine particles other than the vapor phase silica.
Examples of the inorganic fine particles include silica fine particles other than the gas phase method silica, colloidal silica other than the gas phase method silica, titanium dioxide, barium sulfate, calcium silicate, zeolite, kaolinite, halloysite, mica, talc, calcium carbonate. , Magnesium carbonate, calcium sulfate, boehmite, pseudoboehmite and the like. Among these, silica fine particles other than the vapor phase method silica are preferable.
Examples of the silica fine particles other than the vapor phase method silica include the aforementioned wet method particles.

  The average primary particle size of the inorganic fine particles is preferably 20 nm or less, more preferably 15 nm or less, and particularly preferably 10 nm or less. When the average primary particle diameter is 20 nm or less, the ink absorption characteristics can be effectively improved, and at the same time, the glossiness of the ink receiving layer surface can be enhanced.

(Polyvinyl alcohol)
The ink receiving layer according to the present invention contains polyvinyl alcohol in at least both the first ink receiving layer and the second ink receiving layer.
The polyvinyl alcohol used in the present invention has a saponification degree of 90 mol% or more (hereinafter sometimes referred to as “polyvinyl alcohol of the present invention”). When the degree of saponification of polyvinyl alcohol is less than 90 mol%, the unevenness of the stacking is worsened and the surface of the coating (glossiness, cracks) is worsened.
The saponification degree of the polyvinyl alcohol of the present invention is preferably from 90 mol% to 98.5 mol%, more preferably from 92 mol% to 97 mol%, from the viewpoints of suitability for high-speed drying air, uneven stacking, and coated surface shape. More preferably, it is 93 mol%-96 mol%.
The polymerization degree of the polyvinyl alcohol of the present invention is preferably 1,500 to 3,600, and more preferably 2,000 to 3,500. If the degree of polymerization is 1,500 or more, the ink receiving layer is hardly cracked, and if it is 3,600 or less, the viscosity of the coating solution can be lowered.

In this invention, water-soluble resins other than the polyvinyl alcohol of this invention can also be used together with this polyvinyl alcohol. Examples of water-soluble resins that can be used in combination include resins having a hydroxyl group as a hydrophilic structural unit, such as polyvinyl alcohol (PVA) having a saponification degree other than the above range, cation-modified polyvinyl alcohol, anion-modified polyvinyl alcohol, and silanol-modified polyvinyl. Alcohol, polyvinyl acetal, cellulose resin [methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC), hydroxypropyl cellulose (HPC), etc.], chitins, chitosans, starch; hydrophilic Polyethylene oxide (PEO), polypropylene oxide (PPO), polyethylene glycol (PEG), polyvinyl ether (PVE) A resin having an amide group or amide bond of a hydrophilic, polyacrylamide (PAAM), polyvinyl pyrrolidone (PVP) and the like. In addition, polyacrylic acid salts, maleic acid resins, alginic acid salts, gelatins and the like having a carboxyl group as a dissociable group can also be mentioned.
The ratio of the polyvinyl alcohol of the present invention to the total amount of the polyvinyl alcohol of the present invention and the water-soluble resin when the polyvinyl alcohol of the present invention and the above-described water-soluble resin are used in combination is preferably 1 to 30% by mass, 20 mass% is further more preferable and 6-12 mass% is especially preferable.

  As the content of the polyvinyl alcohol of the present invention, it is possible to prevent a decrease in film strength and cracking during drying due to an insufficient content, and the excessive content causes the voids to be easily blocked by a resin. In the first ink receiving layer, from the viewpoint of preventing the ink absorbability from decreasing due to the decrease in the porosity, the mass is from 5% by mass to 30% with respect to the total solid mass of the first ink receiving layer. It is preferable that it is mass%, and it is more preferable that it is 6 mass%-20 mass%. In the second ink receiving layer, from the same viewpoint, it is preferably 5% by mass to 30% by mass, and 6% by mass to 20% by mass with respect to the total solid mass of the second ink receiving layer. More preferably.

Polyvinyl alcohol has a hydroxyl group in its structural unit, and this hydroxyl group and the silanol group on the surface of the silica fine particle form a hydrogen bond, and it is easy to form a three-dimensional network structure in which the secondary particle of the silica fine particle is a chain unit. To do. By forming such a three-dimensional network structure, it is considered that an ink receiving layer having a porous structure with a high porosity can be formed.
In the ink jet recording medium, the porous ink receiving layer obtained as described above can absorb ink rapidly by capillary action and form dots with good roundness without ink bleeding.

(Content ratio of inorganic fine particles and polyvinyl alcohol of the present invention)
Content ratio of inorganic fine particles (preferably silica fine particles; x) and polyvinyl alcohol of the present invention (total amount of the polyvinyl alcohol of the present invention and the water-soluble resin when the water-soluble resin is used in combination) (y) [ The PB ratio (x / y) and the mass of the inorganic fine particles with respect to 1 part by mass of the polyvinyl alcohol of the present invention] have a great influence on the film structure of the ink receiving layer. That is, as the PB ratio increases, the porosity, pore volume, and surface area (per unit mass) increase. Specifically, as the PB ratio (x / y), a decrease in film strength and cracking during drying caused by the PB ratio being too large are prevented, and the PB ratio is too small. From the viewpoint of preventing the gap from being easily blocked by the resin and preventing the ink absorbability from being lowered due to a decrease in the void ratio, 1.5 / 1 to 10/1 is preferable.

  Since stress may be applied to the ink jet recording medium when passing through the transport system of the ink jet printer, the ink receiving layer must have sufficient film strength. Further, when cutting into a sheet, the ink receiving layer needs to have sufficient film strength to prevent cracking and peeling of the ink receiving layer. From such a viewpoint, the PB ratio (x / y) is preferably 5/1 or less, and preferably 2/1 or more from the viewpoint of securing high-speed ink absorbability with an inkjet printer.

For example, a coating solution in which anhydrous silica fine particles having an average primary particle size of 20 nm or less and the polyvinyl alcohol of the present invention are completely dispersed in an aqueous solution with a PB ratio (x / y) of 2/1 to 5/1 is provided on a support. When the coating layer is dried, a three-dimensional network structure in which secondary particles of silica fine particles are chain units is formed, the average pore diameter is 30 nm or less, the porosity is 50% to 80%, the pore ratio volume 0.5 ml / g or more, a surface area of more than 100 m ² / g ratio, a translucent porous membrane can be easily formed.

(Boron compound)
The ink receiving layer according to the present invention contains a boron compound in at least both the first ink receiving layer and the second ink receiving layer.
A boron compound functions as a crosslinking agent which bridge | crosslinks the polyvinyl alcohol of this invention and the water-soluble resin used as needed. An embodiment in which the ink receiving layer according to the present invention is a porous layer cured by a crosslinking reaction of the polyvinyl alcohol of the present invention with a boron compound and a water-soluble resin used as necessary is preferable.

  The content of the boron compound is preferably 0.05 to 0.50 parts by mass, and 0.08 to 0.30 parts by mass with respect to 1.0 part by mass of the polyvinyl alcohol of the present invention. Is more preferable. When the content of the crosslinking agent is within the above range, the polyvinyl alcohol of the present invention can be effectively crosslinked to prevent cracks and the like.

As the boron compound, a cross-linking reaction is rapid, and a suitable one may be appropriately selected in relation to the polyvinyl alcohol of the present invention contained in the ink receiving layer and the water-soluble resin used as necessary. For example, borax, boric acid, borates (eg, _{orthoborate, InBO 3, ScBO 3, YBO} 3, LaBO 3, Mg 3 (BO 3) 2, Co 3 (BO 3) 2, diborate salts (Eg, Mg ₂ B ₂ O ₅ , Co ₂ B ₂ O ₅ ), metaborate (eg, LiBO ₂ , Ca (BO ₂ ) ₂ , NaBO ₂ , KBO ₂ ), tetraborate (eg, Na _{2 B 4 O 7 · 10H 2 O} ), can be cited pentaborate _{(eg, KB 5 O 8 · 4H 2} O, Ca 2 B 6 O 11 · 7H 2 O, CsB 5 O 5) or the like. Among them, Borax, boric acid, and borate are preferable because they can cause a crosslinking reaction promptly.

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

  Isocyanate compounds such as 1,6-hexamethylene diisocyanate; Aziridine compounds described in US Pat. Nos. 3,017,280 and 2,983,611; Carboximide compounds described in US Pat. No. 3,100,704; Glycerol triglycidyl Epoxy compounds such as ether; Ethyleneimino compounds such as 1,6-hexamethylene-N, N′-bisethyleneurea; Halogenated carboxaldehyde compounds such as mucochloric acid and mucophenoxycyclolic acid; 2,3-dihydroxy Dioxane compounds such as dioxane; Titanium lactate, aluminum sulfate, chromium alum, potash alum, metal-containing compounds such as zirconyl acetate and chromium acetate, polyamine compounds such as tetraethylenepentamine, and hydrazide compounds such as adipic acid dihydrazide It is a small molecule or polymer or the like containing an oxazoline group two or more. The above crosslinking agents may be used alone or in combination of two or more.

(Water-soluble zirconium salt)
In the ink receiving layer according to the present invention, at least the first ink receiving layer contains a water-soluble zirconium salt.
The second ink-receiving layer may also contain a water-soluble zirconium salt, but the content of the water-soluble zirconium salt in the first ink-receiving layer is such that the water-soluble zirconium salt in the second ink-receiving layer. In addition, the content of the water-soluble zirconium salt in the second ink receiving layer is more than the content of the vapor phase silica in the second ink receiving layer. It is necessary to be 0.6 mass% or less.

    By including a water-soluble zirconium salt in the first ink-receiving layer, it is possible to improve the unevenness of overlapping, while the content of the water-soluble zirconium salt in the first ink-receiving layer is set to the second level. By increasing the content of the water-soluble zirconium salt in the ink receiving layer, it is possible to prevent deterioration in overlay while providing high-speed air drying suitability for the second ink image-receiving layer. Furthermore, by setting the content of the water-soluble zirconium salt in the second ink receiving layer to 0.6% by mass or less with respect to the content of the vapor phase silica in the second ink receiving layer, High-speed air drying suitability can be imparted.

Specifically, the content of the water-soluble zirconium salt in the first ink receiving layer is 0.5% by mass to 2% by mass higher than the content of the water-soluble zirconium salt in the second ink receiving layer. It is preferably 1% by mass to 1.5% by mass.
Further, the content of the water-soluble zirconium salt in the second ink receiving layer is preferably less than 0.6% by mass with respect to the content of the vapor phase silica in the second ink receiving layer, More preferably, the second ink receiving layer does not contain a water-soluble zirconium salt.
Next, details of the water-soluble zirconium salt will be described.

  The water-soluble zirconium salt is not particularly limited as long as it is a water-soluble compound that forms a salt with metal zirconium. For example, zirconyl acetate, zirconium chloride, zirconium oxychloride, hydroxy zirconium chloride can be used. Zirconium nitrate, basic zirconium carbonate, zirconium hydroxide, zirconium carbonate / ammonium, zirconium carbonate / potassium, zirconium sulfate, zirconium fluoride compound and the like. Zirconyl acetate is particularly preferable.

  The content of the water-soluble zirconium salt in the second ink receiving layer is preferably 0.1% by mass to 1% by mass, and more preferably 0.2% by mass to 0.8% by mass. In addition, the content of the water-soluble zirconium salt in the first ink receiving layer is preferably 1% by mass to 4% by mass with respect to the content of the vapor phase silica in the second ink receiving layer. More preferably, the content is 1.5% by mass to 3% by mass.

  In the present invention, a salt other than the water-soluble zirconium salt can be used in combination. For example, a water-soluble polyvalent metal compound can be used in combination as another salt typified by an aluminum salt. Examples of the water-soluble polyvalent metal compound include water-soluble salts of metals selected from aluminum, calcium, barium, manganese, copper, cobalt, nickel, iron, zinc, chromium, magnesium, tungsten, and molybdenum.

-Aluminum salt-
By using an aluminum salt, it is possible to improve water resistance and aging resistance of recorded images.
As the aluminum salt, for example, aluminum chloride or a hydrate thereof, aluminum sulfate or a hydrate thereof, ammonium alum and the like are known. Furthermore, there is a basic polyaluminum hydroxide compound which is an inorganic aluminum-containing cationic polymer. Among these, a basic polyaluminum hydroxide compound is preferable.

The basic polyaluminum hydroxide compound has a main component represented by the following formula 1, 2 or 3, for example, [Al ₆ (OH) ₁₅ ] ³⁺ , [Al ₈ (OH) ₂₀ ] ⁴⁺ , [Al ₁₃ (OH) ₃₄ ] ⁵⁺ , [Al ₂₁ (OH) ₆₀ ] ³⁺ , and the like, which are water-soluble polyaluminum hydroxides that stably contain basic and high-molecular polynuclear condensed ions.

Formula 1 _{[Al 2 (OH) n Cl 6} -n ] _{m 5 <m <80, 1} <n <5
Formula 2 [Al (OH) ₃ ] _n AlCl ₃ 1 <n <2
Equation _{3 Al n (OH) m Cl} (3n-m) 0 <m <3n, 5 <m <8

  These are water treatment agents from Taki Chemical Co., Ltd. under the name of polyaluminum chloride (PAC), from Asada Chemical Co., Ltd. under the name of polyaluminum hydroxide (Paho), and from Riken Green Co., Ltd. It is marketed under the name of Purachem WT by Daimei Chemical Co., Ltd. under the name of Alpha-In 83 and from other manufacturers for the same purpose, and various grades can be easily obtained. In the present invention, these commercially available products can be used as they are, but there are also products having an inappropriately low pH, and in that case, the pH can be appropriately adjusted and used.

  The content of the aluminum salt in the total ink receiving layer is preferably 0.1% by mass to 20% by mass, more preferably 1% by mass to 8% by mass, and particularly preferably the total solid content of the total ink receiving layer. 1.5 mass% to 4 mass% is most preferable. When the content of the aluminum salt is in the above range, an effect of improving glossiness, water resistance, gas resistance, light resistance and adhesion to the support can be obtained.

-Other salts-
Specific examples of the salt other than the aluminum salt include calcium acetate, calcium chloride, calcium formate, calcium sulfate, barium acetate, barium sulfate, barium phosphate, manganese chloride, manganese acetate, manganese formate dihydrate, Manganese sulfate hexahydrate, cupric chloride, ammonium copper (II) chloride dihydrate, copper sulfate, cobalt chloride, cobalt thiocyanate, cobalt sulfate, nickel sulfate hexahydrate, nickel chloride hexahydrate , Nickel acetate tetrahydrate, nickel ammonium sulfate hexahydrate, nickel amidosulfate tetrahydrate, ferrous bromide, ferrous chloride, ferric chloride, ferrous sulfate, ferric sulfate, Zinc bromide, zinc chloride, zinc nitrate hexahydrate, zinc sulfate, chromium acetate, chromium sulfate, magnesium sulfate, magnesium chloride hexahydrate, citrate mug Siumu nonahydrate, sodium phosphate, sodium tungsten citrate, 12 tungstophosphoric acid n-hydrate, dodecatungstosilicic acid 26-hydrate, molybdenum chloride, dodecamolybdophosphoric acid n-hydrate.

(Water-soluble organic solvent with a boiling point of 120 ° C or higher)
In the ink receiving layer according to the present invention, at least the second ink receiving layer contains a water-soluble organic solvent having a boiling point of 120 ° C. or higher. The content of the water-soluble organic solvent having a boiling point of 120 ° C. or higher in the first ink receiving layer is less than the content of the water-soluble organic solvent having a boiling point of 120 ° C. or higher in the second ink receiving layer, When the first ink receiving layer contains a water-soluble organic solvent having a boiling point of 120 ° C. or higher, the content of the water-soluble organic solvent having a boiling point of 120 ° C. or higher in the first ink receiving layer is It is 2% by mass or less with respect to the content of vapor-phase process silica in the first ink receiving layer.
Hereinafter, a water-soluble organic solvent having a boiling point of 120 ° C. or higher is also referred to as a high-boiling organic solvent.

  By setting the content of the high boiling point organic solvent in the first ink receiving layer to be less than the content of the high boiling point organic solvent in the second ink receiving layer, It becomes possible to have sufficient high-speed air drying suitability, and the content of the high-boiling organic solvent in the first ink receiving layer is larger than the content of the vapor phase silica in the first ink receiving layer. By setting the content to 2% by mass or less, it is considered that the first ink-receiving layer can have sufficient suitability for high-speed air drying.

In the ink jet recording medium of the present invention, the content of the high-boiling organic solvent in the first ink receiving layer is high in the second ink receiving layer from the viewpoint of imparting high-speed air drying suitability to the first ink receiving layer. The content of the boiling organic solvent is preferably 0% by mass to 30% by mass and 0% by mass to 25% by mass with respect to the content of the vapor phase silica in the second ink receiving layer. Is more preferable.
In addition, the content of the high-boiling organic solvent in the first ink receiving layer is the content of the vapor phase silica in the first ink receiving layer from the viewpoint of imparting high-speed air drying suitability to the first ink receiving layer. On the other hand, it is preferably 2 or less, and more preferably, the first ink receiving layer does not contain a high-boiling organic solvent.

The content of the high-boiling organic solvent in the entire coating solution for forming the ink receiving layer is preferably 0.05% by mass to 1% by mass, and particularly preferably 0.1% by mass to 0.6% by mass. .
Next, the details of the high boiling point organic solvent will be described.

  The high-boiling organic solvent is not particularly limited as long as it is a water-soluble organic solvent having a boiling point of 120 ° C. or higher. For example, 1,2-hexanediol (boiling point 122 ° C.), 1-pentanol [boiling point 138 ° C.], 3-methyl-1-butanol (boiling point 131 ° C), 2-methyl-1-butanol (boiling point 128 ° C), ethylene glycol (boiling point 197.6 ° C), propylene glycol (boiling point 187.85 ° C), diethylene glycol (boiling point 244) ° C to 245 ° C], triethylene glycol [boiling point 285 ° C], glycerin [boiling point 290.5 ° C], diethylene glycol monobutyl ether (DEGMBE) [boiling point 230.4 ° C], triethylene glycol monobutyl ether [boiling point 265 to 350 ° C] Glycerol monomethyl ether (3-methoxy-1,2-propanedi (Boiling point 220 ° C.), 1,2,3-butanetriol, 1,2,4-butanetriol [boiling point 190 to 191 ° C./18 mmHg (lit.)], 1,2,4-pentanetriol, 1 , 2,6-hexanetriol [boiling point 178 ° C./5 mmHg (lit.)], thiodiglycol [boiling point 282 ° C.], triethanolamine [boiling point 360 ° C.], polyethylene glycol (weight average molecular weight of 400 or less) Kind.

Among the high-boiling organic solvents, a water-soluble organic solvent having a boiling point of 150 ° C. or higher is preferable, and a water-soluble organic solvent having a boiling point of 180 ° C. or higher is more preferable.
Further, from the viewpoints of printing density, curling, and bleeding, dialkylene glycol monoalkyl ether is preferable, and diethylene glycol monobutyl ether (DEGMBE) is more preferable.

(Other ingredients)
The ink receiving layer of the present invention comprises the following components as necessary.
That is, for the purpose of suppressing the deterioration of the ink coloring material, various ultraviolet absorbers, antioxidants, anti-fading agents such as singlet oxygen quenchers may be included.
Examples of the ultraviolet absorber include cinnamic acid derivatives, benzophenone derivatives, benzotriazolylphenol derivatives, and the like. For example, α-cyano-phenyl cinnamate butyl, o-benzotriazole phenol, o-benzotriazole-p-chlorophenol, o-benzotriazole-2,4-di-t-butylphenol, o-benzotriazole-2,4 -Di-t-octylphenol etc. are mentioned. A hindered phenol compound can also be used as an ultraviolet absorber, and specifically, a phenol derivative in which one or more of at least 2-position or 6-position is substituted with a branched alkyl group is preferable.

  Moreover, a benzotriazole type ultraviolet absorber, a salicylic acid type ultraviolet absorber, a cyanoacrylate type ultraviolet absorber, an oxalic acid anilide type ultraviolet absorber, etc. can be used. For example, JP-A-47-10537, 58-111942, 58-21284, 59-19945, 59-46646, 59-109055, 63-53544. No. 36, Japanese Patent Publication No. 36-10466, No. 42-26187, No. 48-30492, No. 48-31255, No. 48-41572, No. 48-54965, No. 50-10726. No. 2,719,086, US Pat. No. 3,707,375, US Pat. No. 3,754,919, US Pat. No. 4,220,711, and the like. .

  A fluorescent brightening agent can also be used as an ultraviolet absorber, and examples thereof include a coumarin fluorescent brightening agent. Specifically, it is described in Japanese Patent Publication Nos. 45-4699 and 54-5324.

  Examples of the antioxidant include European Patent Publication No. 223739, Publication No. 309401, Publication No. 309402, Publication No. 310551, Publication No. 310552, Publication No. 4594416, Publication of German Patent No. 3435443, JP-A-54-48535, JP-A-60-107384, JP-A-60-107383, JP-A-60-125470, JP-A-60-125471, JP-A-60-125472, JP-A-60-287485. 60-287486, 60-287487, 60-287488, 61-160287, 61-185483, 61-2111079, 62-146678, 62-146680, 62-146679, 62-282885, JP same 62-262047, JP-same 63-051174, JP-same 63-89877, JP-same 63-88380, JP-same 66-88381, JP-same 63-113536 JP;

  JP-A-63-163351, JP-A-63-203372, JP-A-63-224989, JP-A-63-251282, JP-A-63-267594, JP-A-63-182484, JP-A-1-239282, JP-A-2-262654, JP-A-2-71262, JP-A-3-121449, JP-A-4-29185, JP-A-4-291684, JP-A-5-61166, JP-A-5-119449, 5-188687, 5-188686, 5-110490, 5-110437, 5-170361, JP 48-43295, 48-33212, Examples thereof include those described in U.S. Pat. Nos. 4,814,262 and 4,980,275.

  Specifically, 6-ethoxy-1-phenyl-2,2,4-trimethyl-1,2-dihydroquinoline, 6-ethoxy-1-octyl-2,2,4-trimethyl-1,2-dihydroquinoline 6-ethoxy-1-phenyl-2,2,4-trimethyl-1,2,3,4-tetrahydroquinoline, 6-ethoxy-1-octyl-2,2,4-trimethyl-1,2,3 4, -tetrahydroquinoline, nickel cyclohexane acid, 2,2-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) -2-ethylhexane, 2-methyl-4-methoxy-diphenylamine, Examples include 1-methyl-2-phenylindole.

These anti-fading agents may be used alone or in combination of two or more. The anti-fading agent may be water-solubilized, dispersed, emulsified, or included in microcapsules. The addition amount of the antifading agent is preferably 0.01 to 10% by mass of the ink receiving layer forming liquid.
Further, for the purpose of enhancing the dispersibility of the inorganic fine particles, various inorganic salts and pH adjusting agents may contain acids, alkalis and the like.
Further, for the purpose of suppressing surface frictional charge and peeling charge, the metal oxide fine particles having electronic conductivity may contain various matting agents for the purpose of reducing the surface frictional characteristics.

(Glossy expression layer)
The inkjet recording medium of the present invention has a gloss expression containing colloidal silica at a position farthest from the non-absorbing support, that is, an outermost layer on the side where the ink-receiving layer of the non-absorbing support is provided. It is preferable to have a layer.
When the inkjet recording medium of the present invention has a glossy expression layer, high glossiness is obtained in addition to the effect of having an excellent surface shape and excellent ink absorbability.
More preferably, the ink receiving layer (particularly the second ink receiving layer) and the glossy layer are provided in contact with each other.

  The colloidal silica used in the glossy layer is a colloidal dispersion of silicon dioxide obtained by heating and aging a silica sol obtained through metathesis or acid exchange resin layer of sodium silicate and the like, It is a wet method synthetic silica having an average primary particle size of about several nm to 100 nm. Colloidal silica is available from Nissan Chemical Industries, Ltd. Snowtex ST-20, ST-30, ST-40, ST-C, ST-N, ST-20L, ST-O, ST-OL, ST-S. ST-XS, ST-XL, ST-YL, ST-ZL, ST-OZL, ST-AK and the like are commercially available.

  The colloidal silica used in the glossy expression layer preferably has an average primary particle size in the range of 30 nm to 100 nm from the viewpoint of ink absorbability and gloss. Furthermore, it is preferable to use two or more types of colloidal silica having different average primary particle diameters in combination. In this case, it is more preferable to use a combination of colloidal silica having an average primary particle diameter of 30 nm to less than 60 nm and colloidal silica having an average primary particle diameter of 60 nm to 100 nm, and the average primary particle diameter with respect to the total amount of colloidal silica. The ratio of colloidal silica of 30 nm to less than 60 nm is preferably 60% by mass or more.

The particle shape of the colloidal silica includes a spherical shape, a chain shape (beaded shape), and the like, and a spherical colloidal silica is preferable in terms of the effects of the present invention, particularly scratch resistance and gloss.
The colloidal silica has an anionic property, a nonionic property, and a cationic property, but the stability of the coating solution of the colloidal silica layer, particularly the stability of the coating solution containing polyvinyl alcohol as an organic binder (the colloidal over time of the coating solution). Anionic properties are preferred in terms of silica aggregation and separation.

0.1-8.0 g / m < ² > is preferable and, as for the solid content coating amount of the colloidal silica in a glossiness expression layer, the range of 0.3-5.0 g / m < ² > is more preferable. Thereby, the gloss and scratch resistance can be further improved without lowering the ink absorbability.

The glossy layer preferably contains a cationic compound. As the cationic compound, a cationic polymer or a water-soluble polyvalent metal compound represented by the water-soluble zirconium salt or the aluminum salt is preferably used.
Examples of the cationic polymer include water-soluble cationic polymers having a quaternary ammonium group, a phosphonium group, or an acid adduct of a primary to tertiary amine. For example, polyethylenimine, polydialkyldiallylamine, polyallylamine, allylamine epichlorohydrin polycondensate, JP-A-59-20696, 59-33176, 59-33177, 59-155888, 60-11389 60-49990, 60-83882, 60-109894, 62-198493, 63-49478, 63-115780, 63-280681, JP-A-1-40371, Examples thereof include cationic polymers described in JP-A-6-234268, JP-A-7-125411, JP-A-10-193976, and the like. The weight average molecular weight of the cationic polymer used in the present invention is preferably 100,000 or less, more preferably 50,000 or less, and the lower limit is about 2,000.

  Examples of the polyvalent metal in the water-soluble polyvalent metal compound include calcium, barium, manganese, copper, cobalt, nickel, aluminum, iron, zinc, zirconium, titanium, chromium, magnesium, tungsten, and molybdenum. It can be used as a water-soluble metal salt. Specifically, for example, calcium acetate, calcium chloride, calcium formate, calcium sulfate, barium acetate, barium sulfate, barium phosphate, manganese chloride, manganese acetate, manganese formate dihydrate, manganese ammonium sulfate hexahydrate, chloride chloride Dicopper, ammonium copper (II) chloride dihydrate, copper sulfate, cobalt chloride, cobalt thiocyanate, cobalt sulfate, nickel sulfate hexahydrate, nickel chloride hexahydrate, nickel acetate tetrahydrate, nickel sulfate Ammonium hexahydrate, nickel amidosulfate tetrahydrate, aluminum sulfate, aluminum sulfite, aluminum thiosulfate, polyaluminum chloride, aluminum nitrate nonahydrate, aluminum chloride hexahydrate, ferrous bromide, ferric chloride Ferrous, ferric chloride, ferrous sulfate, ferric sulfate, zinc bromide, zinc chloride, zinc nitrate Hydrates, zinc sulfate, zirconium acetate, zirconium nitrate, basic zirconium carbonate, zirconium hydroxide, zirconium carbonate / ammonium, zirconium carbonate / potassium, zirconium sulfate, zirconium fluoride, zirconium chloride, zirconium chloride octahydrate, oxy Zirconium chloride, hydroxy zirconium chloride, titanium chloride, titanium sulfate, chromium acetate, chromium sulfate, magnesium sulfate, magnesium chloride hexahydrate, magnesium citrate nonahydrate, sodium phosphotungstate, sodium tungsten citrate, 12 tungstorin Examples include acid n hydrate, 12 tungstosilicic acid 26 hydrate, molybdenum chloride, 12 molybdophosphoric acid n hydrate, and the like. Among these, aluminum or a water-soluble salt of a periodic table group IVa element (zirconium, titanium) is preferable. In the present invention, water-soluble means that 1% by mass or more dissolves in water at room temperature and normal pressure.

  0.1-10 mass% is preferable with respect to colloidal silica, and, as for the addition amount of the said cationic compound, the range of 0.5-8.0 mass% is more preferable.

  The glossy layer preferably further contains an organic binder. The organic binder is preferably used at 10% by mass or less based on colloidal silica, and the lower limit is about 0.5% by mass. More preferably, the organic binder is used in the range of 1 to 7% by mass. By containing the organic binder in this range, the scratch resistance is further improved without lowering the ink absorbability.

  As the organic binder, various water-soluble resins or polymer latexes are preferably used as the organic binder. As the water-soluble resin, for example, polyvinyl alcohol, polyethylene glycol, starch, dextrin, carboxymethyl cellulose, polyvinyl pyrrolidone, polyacrylic acid ester and the like and derivatives thereof are used. Particularly preferred organic binders are completely or partially saponified. Polyvinyl alcohol or cation-modified polyvinyl alcohol.

  Particularly preferred among the polyvinyl alcohols are those having a degree of saponification of 80% or more or those completely saponified. Polyvinyl alcohol having an average degree of polymerization of 500 to 5000 is preferred. The cation-modified polyvinyl alcohol has a primary to tertiary amino group or a quaternary ammonium group in the main chain or side chain of the polyvinyl alcohol as described in, for example, JP-A-61-10383. Polyvinyl alcohol.

Examples of the polymer latex used as the organic binder include acrylic latexes such as alkyl ester, aryl group, aralkyl group, and hydroxyalkyl group, such as acrylic ester or methacrylic ester, acrylonitrile, acrylamide, acrylic acid. And methacrylic acid or other homopolymers or copolymers, or the above monomers and styrene sulfonic acid, vinyl sulfonic acid, itaconic acid, maleic acid, fumaric acid, maleic anhydride, vinyl isocyanate, allyl isocyanate, vinyl methyl ether, acetic acid Examples thereof include copolymers with vinyl, styrene, divinylbenzene and the like. As the olefin latex, a polymer comprising a copolymer of a vinyl monomer and a diolefin is preferable. As the vinyl monomer, styrene, acrylonitrile, methacrylonitrile, methyl acrylate, methyl methacrylate, vinyl acetate, or the like is preferably used. Examples include butadiene, isoprene, chloroprene and the like.
Among these, a particularly preferable organic binder is completely or partially saponified polyvinyl alcohol or cation-modified polyvinyl alcohol. Particularly preferred among the polyvinyl alcohols are those having a degree of saponification of 80% or more or those completely saponified. Polyvinyl alcohol having an average degree of polymerization of 500 to 5000 is preferred.

  The cation-modified polyvinyl alcohol has a primary to tertiary amino group or a quaternary ammonium group in the main chain or side chain of the polyvinyl alcohol as described in, for example, JP-A-61-10383. Polyvinyl alcohol.

  For the glossy layer, a hardener can be used together with an organic binder. Examples of the hardener include the aforementioned boron compounds. Of these, boric acid or borate is particularly preferably used. Other colloidal silica layers include surfactants, colored dyes, colored pigments, UV absorbers, antioxidants, pigment dispersants, antifoaming agents, leveling agents, preservatives, fluorescent whitening agents, viscosity stabilizers, A pH regulator and the like can be contained.

  In the present invention, the glossy layer has a layer thickness of preferably 0.01 μm to 5 μm, more preferably 0.02 μm to 1 μm.

[Other layers]
The ink jet recording medium of the present invention has a layer other than the ink receiving layer on the non-absorbent support, for example, an intermediate layer and a functional layer imparted with functions such as cushioning and antistatic properties as necessary. It may be. However, from the viewpoint of not impairing the effects of the ink receiving layer according to the present invention, it is preferable that no other layer is provided between the first ink receiving layer and the second ink receiving layer. The second ink receiving layer is preferably further away from the non-absorbing support than the first ink receiving layer.

(Non-absorbent support)
As the non-absorbent support, either a transparent support made of a transparent material such as plastic or an opaque support made of an opaque material such as paper can be used. In order to make use of the transparency of the ink receiving layer, it is preferable to use a transparent support or a highly glossy opaque support. Further, a read-only optical disk such as CD-ROM or DVD-ROM, a write-once optical disk such as CD-R or DVD-R, or a rewritable optical disk may be used as a support, and an ink receiving layer may be provided on the label surface side. it can.

In the present invention, “non-absorptive” means that it does not absorb water and the solvent contained in the ink for ink jet recording, or that the absorbed amount is 0.3 g / m ² or less, and particularly does not absorb water. Say.

The material that can be used for the transparent support is preferably a material that is transparent and can withstand radiant heat when used in an OHP or backlight display. Examples of such materials include polyesters such as polyethylene terephthalate (PET); polysulfone, polyphenylene oxide, polyimide, polycarbonate, polyamide, and the like. Of these, polyesters are preferable, and polyethylene terephthalate is particularly preferable.
The thickness of the transparent support is not particularly limited, but is preferably 50 μm to 200 μm from the viewpoint of ease of handling.

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

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

Although there is no restriction | limiting in particular also about the thickness of the said opaque support body, 50 micrometers-300 micrometers are preferable at the point of the ease of handling.
In addition, it is preferable to use a surface of the support that has been subjected to corona discharge treatment, glow discharge treatment, flame treatment, ultraviolet irradiation treatment or the like in order to improve wettability and adhesion.

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

As the above-mentioned pulp, chemical pulp (sulfate pulp or sulfite pulp) with few impurities is suitably used, and a pulp whose whiteness is improved by performing a bleaching treatment is also useful.
In the base paper, sizing agents such as higher fatty acids and alkyl ketene dimers, white pigments such as calcium carbonate, talc and titanium oxide, paper strength enhancing agents such as starch, polyacrylamide and polyvinyl alcohol, fluorescent whitening agents, polyethylene glycols A water retaining agent such as a dispersant, a softening agent such as a quaternary ammonium, and the like can be appropriately added.

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

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

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

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

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

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

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

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

<Inkjet recording medium manufacturing method>
In the method for producing an ink jet recording medium of the present invention, a coating solution A containing vapor-phase-process silica, polyvinyl alcohol having a saponification degree of 90 mol% or more, a boron compound, and a water-soluble zirconium salt on a non-absorbent support. And a coating solution B containing a vapor phase silica, a polyvinyl alcohol having a saponification degree of 90 mol% or more, a boron compound, and a water-soluble organic solvent having a boiling point of 120 ° C. or more on the coating solution A, An ink receiving layer is formed by applying multiple layers simultaneously so that the coating liquid B overlaps. That is, the coating liquid A and the coating liquid B are simultaneously applied in the order of the coating liquid A and the coating liquid B from the non-absorbing support side to form an ink receiving layer.
At this time, the content of the water-soluble zirconium salt in the coating solution B is made smaller than the content of the water-soluble zirconium salt in the coating solution A, and the coating solution B contains a water-soluble zirconium salt. In some cases, the content of the water-soluble zirconium salt in the coating solution B is 0.6% by mass or less with respect to the content of the vapor phase silica in the coating solution B. Furthermore, the content of the water-soluble organic solvent having a boiling point of 120 ° C. or higher in the coating liquid A is less than the content of the water-soluble organic solvent having a boiling point of 120 ° C. or higher in the coating liquid B, and When the coating liquid A contains a water-soluble organic solvent having a boiling point of 120 ° C. or higher, the content of the water-soluble organic solvent having a boiling point of 120 ° C. or higher in the coating liquid A is determined by the vapor phase method silica in the coating liquid A. It is comprised so that it may become 2 mass% or less with respect to content of.
The method for producing an ink jet recording medium of the present invention may further include other steps as necessary.

The ink receiving layer of the ink jet recording medium of the present invention is formed by coating the coating liquid A or the coating liquid B, which is a coating liquid for forming an ink receiving layer, on a non-absorbing support or an already formed ink receiving layer. Then, it can be formed by forming a coating layer and drying it.
When the ink receiving layer of the inkjet recording medium of the present invention has a two-layer structure, the first ink receiving layer can be formed by applying the coating liquid A on a non-absorbent support. In addition, the second ink receiving layer can be formed by applying the coating liquid B on the first ink receiving layer.

  According to the simultaneous multilayer coating in which a plurality of layers constituting the ink receiving layer are applied almost simultaneously without providing a drying step, the characteristics required for each layer can be obtained efficiently, and the production efficiency is excellent. That is, by laminating each layer in a wet state, the component contained in each layer, for example, the upper layer (for example, the second ink receiving layer in the inkjet recording medium of the present invention) is converted into the lower layer (for example, in the inkjet recording medium of the present invention). This is presumably because the composition of the components of each layer is well maintained even after drying.

  The simultaneous multilayer coating can be performed using a known coating apparatus, and examples thereof include a slide bead coater, a curtain flow coater, and an extrusion die coater.

  The first ink-receiving layer contains the polyvinyl alcohol of the present invention contained in the coating solution A, boric acid, a high-boiling organic solvent, and the types and contents of various components contained as necessary. It is the same as the kind and content of various components, and the preferable range is also the same. The second ink-receiving layer contains the polyvinyl alcohol, boric acid and water-soluble zirconium salt of the present invention contained in the coating liquid B, and the types and contents of various components contained as necessary. It is the same as the kind and content of various components, and the preferable range is also the same.

The contents of the vapor phase silica contained in the coating liquid A and the coating liquid B are respectively the contents of the vapor phase silica contained in the first ink receiving layer and the second ink receiving layer. Is the same as the content of the vapor phase silica contained in the same, and the preferred range is also the same, but the particle size (average secondary particle size) of the silica fine particles of the vapor phase silica contained in each coating solution is in the following range. It is preferable that
The silica fine particle diameter (average secondary particle diameter) of vapor phase silica in the coating liquid A (first ink-receiving layer coating liquid) is 100 nm to 170 nm from the viewpoint of improving glossiness (image clarity). Is preferable, and it is more preferable that it is 110 nm-150 nm.
Further, the silica fine particle diameter (average secondary particle diameter) of the vapor phase method silica in the coating liquid B (second ink-receiving layer coating liquid) is preferably 80 nm to 130 nm from the viewpoint of printing density, and is 90 nm. More preferably, it is -120 nm.
In the present invention, the particle size (average secondary particle size) of the silica fine particles refers to a value measured using a laser diffraction particle size distribution measuring device “LA920” manufactured by Horiba, Ltd.

  In the present invention, the gas phase method silica contained in the coating solution B is preferably dispersed using a high-pressure disperser of 30 MPa to 300 MPa, and the gas phase method silica contained in the coating solution A uses beads. It is preferable to disperse. When the vapor phase silica is dispersed using a high-pressure disperser, it is considered that the silica fine particles of the vapor phase silica are reduced and the silica particle diameter of the coating liquid B is reduced. On the other hand, when the vapor phase silica is dispersed using beads, the silica fine particles of the vapor phase silica are difficult to be reduced. Therefore, even if the coating liquid A comes into contact with the coating liquid B, the silica aggregation of the coating liquid A is suppressed. Conceivable. Further, when the ink receiving layer is formed using the coating liquid A in which the vapor phase method silica is dispersed using such beads, the glossiness of the ink jet recording medium can be improved.

  From the viewpoint of setting the silica fine particle diameter of the vapor phase method silica in the first ink receiving layer coating liquid (coating liquid A) in the present invention to 100 nm to 170 nm, the coating liquid A that can be used for forming the first ink receiving layer is The contained vapor phase method silica is preferably dispersed using beads. Further, from the viewpoint of setting the silica fine particle diameter of the vapor phase method silica in the second ink receiving layer coating liquid (coating liquid B) to 80 nm to 130 nm, the coating liquid B that can be used for forming the second ink receiving layer is contained. The vapor phase silica to be dispersed is preferably dispersed using a high-pressure disperser.

  The “high pressure” of the high-pressure disperser refers to a pressure of 30 MPa to 300 MPa, and the high-pressure disperser mainly causes silica fine particles to enter the liquid by colliding vapor phase silica with the wall surface at a pressure of 50 MPa to 200 MPa. It has a dispersion mechanism for dispersion. An example of an apparatus having such a dispersion mechanism is an optimizer manufactured by Sugino Machine.

  As the dispersion using beads, for example, beads having a particle size of 0.1 mm to 3 mm are added to a solution containing vapor phase method silica at a bead filling rate of 50% to 90%, and the peripheral speed is set to 0. Examples of the dispersion mechanism include stirring at 5 m / s to 12 m / s. A sharp particle size distribution is easily obtained by setting the number of passes to 2 or more. An example of an apparatus having such a dispersion mechanism is Dynomill KDP manufactured by Shinmaru Enterprise. As dispersion conditions, beads having a particle diameter of 0.65 mm are filled in a solution containing gas phase method silica at a filling rate of 70%. And can be dispersed with a peripheral speed of 8 m / s and a pass number of 2 times.

The coating amount of the first coating solution A for an ink receiving layer is preferably ^3g / ^{m 2 ~20g} / m 2 in terms of solid content, more preferably ^{5g / m 2 ~10g / m 2} . As the coating weight of the second coating solution B for forming the ink receiving layer, is preferably ³ / ^{m 2 ~20g} / m 2 in terms of solid content, more preferably at ^5g / ^{m 2 ~10g} / m 2 . When the coating amount is within the above range, the drying property of the coating film is good, and the occurrence of cracks can be avoided.

The vapor phase silica contained in the ink receiving layer is preferably added to the coating liquid for forming the ink receiving layer as a silica dispersion using a silica dispersant. Similarly, the colloidal silica contained in the glossy layer is preferably added to the coating liquid for forming the glossy layer as a silica dispersion using a silica dispersant.
At this time, it is preferable to use a cationic resin as the silica dispersant. This also has a mordanting function of ink (dye). Although it does not specifically limit as this cationic resin, The cationic polymer which has a primary-tertiary amino group and its salt, and a quaternary ammonium base is suitable. It is also preferable to use a silane coupling agent as the dispersant.

Specifically, water-soluble or aqueous emulsion types can be suitably used. For example, dicyan cation resins represented by dicyandiamide-formalin polycondensates, polyamine cation resins represented by dicyanamide-diethylenetriamine polycondensates , epichlorohydrin - dimethylamine addition polymers, dimethyldiallylammonium chloride -SO ₂ copolymer, diallylamine salt -SO ₂ copolymer, dimethyl diallyl ammonium chloride polymer, polymer of allylamine salt, dialkylaminoethyl (meth) acrylate 4 Examples thereof include polycationic cation resins such as quaternary salt polymers and acrylamide-diallylamine salt copolymers. Of these, dimethyldiallylammonium chloride, monomethyldiallylammonium chloride and polyamidine are preferred, and dimethyldiallylammonium chloride and monomethylammonium chloride are particularly preferred from the viewpoint of water resistance. The cationic resins may be used alone or in combination of two or more.
The molecular weight of the cationic resin is preferably 2,000 to 100,000, and more preferably 5,000 to 20,000.

  The addition amount of the cationic resin is preferably 0.2% by mass to 10% by mass and more preferably 1.5% by mass to 5% by mass with respect to the mass of the vapor phase silica. If the added amount is less than 0.2% by mass, the dispersibility may be inferior. If the added amount exceeds 10% by mass, the color density may be lowered during printing. The cationic resin may be added in a small amount before pulverization and dispersion, and then pulverized and dispersed until a desired particle size is obtained, and then further added.

  In the method for producing an inkjet recording medium of the present invention, it is preferable to dry the ink receiving layer under conditions including the case where the film surface temperature of the coating film is less than 20 ° C. That is, it is sufficient that the drying process includes a drying stage in which the film surface temperature is less than 20 ° C., the film surface temperature may be less than 20 ° C. in the initial stage of drying, and a predetermined time has elapsed from the start of drying. The film surface temperature may be lowered to less than 20 ° C. after or after the drying. Among these, from the viewpoint of uniform coated surface shape and void volume, it is preferable to carry out the drying stage in which the film surface temperature is less than 20 ° C. at the initial stage of drying, particularly immediately after the start of drying. By performing drying so that the film surface temperature is less than 20 ° C. at the initial stage of drying (especially immediately after the start of drying), uneven drying can be avoided even when the coating liquid has a low viscosity, and glossiness can be enhanced. When the initial drying stage is dried at a high temperature, particularly when the viscosity of the coating solution is low, uneven drying occurs and glossiness decreases.

By providing a drying step in which the film surface temperature is less than 20 ° C., the film surface of the coating liquid is thickened, and a more uniform coated surface shape can be obtained. The film surface temperature is preferably 0 or more and less than 20 ° C., more preferably 5 or more and 15 ° C. or less. By setting the film surface temperature to 0 ° C. or higher, it is possible to suppress the excessive increase in the viscosity of the coating liquid, to prevent the formation of unevenness on the surface of the coating film, and to obtain higher glossiness.
Here, the film surface temperature is the temperature of the coating film surface during drying, and can be measured with a radiation thermometer.

  Although drying temperature is based also on the heat resistance of a nonabsorbent support body, 10-120 degreeC is preferable, More preferably, it is 20-90 degreeC. When the drying temperature is within the above range, the ink absorbability can be further improved, and the water resistance of the ink receiving layer can also be improved.

<< Recovery process >>
In the inkjet recording method of the present invention, the collecting step stacks and collects a plurality of inkjet recording media on which images are recorded after image recording.

  When images are continuously recorded by ink jet recording, ink for ink jet recording is applied to the surface of a certain ink jet recording medium (hereinafter referred to as “nth ink jet recording medium”, where n represents an integer of 1 or more). Then, an image is recorded, and then an image is recorded on the surface of the next inkjet recording medium (hereinafter, “n + 1th inkjet recording medium”) in the same manner as described above, and then the nth inkjet recording is performed. The (n + 1) th ink jet recording medium is stacked on the medium. In the same manner, the first sheet,..., The nth sheet, the (n + 1) th sheet,... Are recorded and printed in such a manner that they are stacked.

  Here, after the image is recorded on the nth inkjet recording medium, the n + 1th inkjet recording medium and the (n + 1) th inkjet recording are performed when the (n + 1) th inkjet recording medium is stacked. A portion having an overlap with the medium (laminated portion) and a portion having no overlap (non-laminated portion) are generated. Thereby, conventionally, a density difference and a color difference between the laminated portion and the non-laminated portion are likely to occur. In particular, when the ink jet recording medium is laminated immediately after recording, the upper ink jet recording medium overlaps the surface of the image receiving layer of the lower ink jet recording medium, so that the density difference and color difference are significant.

  The time from when the image is recorded on the n-th inkjet recording medium, and after the recording is completed, to the n-th inkjet recording medium after the inkjet recording on the (n + 1) th inkjet recording medium ( When the elapsed time from ink-jet recording to stacking is short, density differences and color differences are particularly significant. That is, the density difference and color difference in high-speed printing become significant.

The ink jet recording method of the present invention enables recording of an ink jet image having a small density difference and color difference by forming an image using the ink for ink jet recording described above.
When the elapsed time from the end of ink jet recording to stacking is within 30 seconds, the effects of density difference and color difference are remarkably small, and it is preferable in that the time is less than 10 seconds. Here, “end of ink jet recording” means “when the ink droplet ejected from the nozzle of the ink jet head has finally landed on the ink receiving layer”.

  In the ink jet recording method of the present invention, energy is supplied to the ink for ink jet recording to record an image on the ink jet recording medium of the present invention. The ink for ink jet recording may be provided in the ink set for ink jet recording.

  When an image is recorded on the ink jet recording medium of the present invention, a polymer latex compound may be used in combination for the purpose of imparting glossiness or water resistance or improving weather resistance. The timing of applying the latex compound to the ink jet recording medium may be before, after, or at the same time as the application of the colorant. It may be in the ink or may be used as a liquid material of polymer latex alone. Specifically, the methods described in Japanese Patent Application Nos. 2000-363090, 2000-315231, 2000-354380, 2000-343944, and 2000-268952 can be preferably used.

EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited by the following Example. In the examples, “parts” and “%” are based on mass.
[Example 1]
(Preparation of non-absorbable support)
50 parts of LBKP made of acacia and 50 parts of LBKP made of aspen were each beaten to 300 ml of Canadian freeness by a disc refiner to prepare a pulp slurry.
Subsequently, to the pulp slurry obtained as described above, 1.3% of cationic starch (made by NSC Japan, CAT0304L), 0.15% anionic polyacrylamide (made by Seiko Chemical Co., Ltd., polyaclon ST-13) per pulp. After adding 0.29% of alkyl ketene dimer (Arakawa Chemical Co., Ltd., Size Pine K), 0.29% of epoxidized behenamide, 0.32% of polyamide polyamine epichlorohydrin (Arakawa Chemical Co., Ltd., Arafix 100) Antifoam 0.12% was added.

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

After the corona discharge treatment was performed on the wire surface (back surface) side of the obtained base paper, high-density polyethylene was coated to a thickness of 30 μm using a melt extruder, and a thermoplastic resin layer comprising a mat surface was formed. (Hereinafter, this thermoplastic resin layer surface is referred to as “back surface”). The thermoplastic resin layer on the back side is further subjected to corona discharge treatment, and then, as an antistatic agent, aluminum oxide (“Alumina Sol 100” manufactured by Nissan Chemical Industries, Ltd.) and silicon dioxide (manufactured by Nissan Chemical Industries, Ltd.). “Snowtex O”) was dispersed in water at a mass ratio of 1: 2 so that the dry weight was 0.2 g / m ² . Subsequently, the surface was subjected to corona treatment, and polyethylene having a density of 0.93 g / m ² having 10% by mass of titanium oxide was coated using a melt extruder so as to be 24 g / m ² .

<Preparation of coating liquid B for forming the second ink receiving layer (upper layer)>
CONTI-TDS (Dalton Co., Ltd.) (1) gas phase method silica fine particles having the following composition B1, (2) ion-exchanged water, (3) “Charol DC-902P”, and (4) zircosol “ZA-30” Then, fine dispersion was performed at a pressure of 130 MPa using an optimizer (manufactured by Sugino Machine Co., Ltd.), which is a high-pressure disperser, to obtain a silica dispersion.

  Thereafter, the silica dispersion was heated to 45 ° C. and held for 20 hours. Next, (5) boric acid described in the following composition B2 in the silica dispersion, (6) polyvinyl alcohol solution P1, (7) ion-exchanged water, (8) SC507, (9) Superflex 650-5, (10) Emulgen 109P was added at 30 ° C. to prepare a coating liquid B for forming the second ink receiving layer (upper layer).

-Composition B1-
(1) Gas phase method silica fine particle ... 207.7 parts [AEROSIL300SV, manufactured by Nippon Aerosil Co., Ltd.]
(2) Ion-exchanged water ... 836 parts (3) "Charol DC-902P" (51.5% aqueous solution) ... 18.2 parts [Dispersant, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.]
(4) Zircosol “ZA-30” (50% aqueous solution) 2.8 parts [Zirconium acetate, manufactured by Daiichi Rare Element Chemical Industries, Ltd., water-soluble zirconium salt]

-Composition B2-
(5) Boric acid (7.5% aqueous solution) [crosslinking agent] ... 102 parts (6) Polyvinyl alcohol solution P1 [binder] ... 605 parts (7) Ion-exchanged water ... 272 parts (8 ) SC507 ... 1.61 parts [polyalkylene polyamine, dimethylamine, epichlorohydrin polycondensate,
Made by Hymo Co., Ltd.)
(9) Superflex 650-5 41.0 parts [cationic polyurethane fine particles, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.]
(10) "Emulgen 109P" (10% aqueous solution) ... 13.2 parts [manufactured by Kao Corporation, HLB value 13.6]

The composition of the polyvinyl alcohol solution P1 is as shown in the following composition P1.
-Composition P1-
-"JM33" [PVA] ... 440 parts [manufactured by Nippon Vinegar Bipvar, saponification degree 95 mol%, polymerization degree 3,300]
・ Polyoxyethylene lauryl ether [surfactant] 7.3 parts [Emulgen 109P, 10% aqueous solution, HLB value 13.6, manufactured by Kao Corporation]
・ Diethylene glycol monobutyl ether (DEGMBE) 134 parts [Kyowa Hakko Chemical Co., Ltd., Butisenol 20P, high boiling point organic solvent]
・ Hydroxypropyl cellulose 20 parts [Nippon Soda Co., Ltd. “HPC-SSL”]
・ Ion exchange water: 5743 parts

<Preparation of coating liquid A for forming the first ink receiving layer (lower layer)>
In the preparation of the coating solution B, 11.2 parts of “ZA-30” (manufactured by Daiichi Rare Elemental Chemical Co., Ltd.) is added, and diethylene glycol monobutyl ether added to the polyvinyl alcohol solution P1 Was changed to 33.5 parts, and the amount of ion-exchanged water added was adjusted so that the concentration of the vapor phase silica was the same as the concentration of the vapor phase silica in the coating solution B. A coating solution A for forming the first ink receiving layer (lower layer) was prepared in the same manner as the others.

<Preparation of inkjet recording sheet>
After the corona discharge treatment is applied to the front surface (side on which the ink receiving layer is provided) of the non-absorbent support, the aqueous solution of polyaluminum chloride is applied to each coating solution using a static mixer. In-line addition, and then simultaneous multi-layer coating with a slide bead coater. A coating film for forming a first ink receiving layer and a coating film for forming a second ink receiving layer are formed on the front surface in order from the front surface. Was established.

The coating liquid A or the coating liquid B and the polyaluminum chloride aqueous solution were applied so as to have the following coating amounts.
(Second ink receiving layer (upper layer))
・ Coating liquid B 41.3 g / m ²
-4.6% aqueous polyaluminum chloride solution 2.8 g / m ²
[Daiming Chemical Co., Ltd., Alpha-in 83, aluminum salt]
(First ink receiving layer (lower layer))
・ Coating liquid A 123.8 g / m ²
・ 4.6% polyaluminum chloride aqueous solution 8.6 g / m ²
[Daiming Chemical Co., Ltd., Alpha-in 83, aluminum salt]

The obtained coating film was cooled with air at 30 ° C. and 10 m / s for 1 minute, and after cooling, dried at 50 ° C. for 10 minutes to obtain a two-layer ink receiving layer.
Thus, an inkjet recording sheet 1 provided with an ink receiving layer having a dry layer thickness of 35 μm (the total thickness of the first ink receiving layer and the second ink receiving layer) was prepared. The layer thickness ratio between the first ink receiving layer (lower layer) and the second ink receiving layer (upper layer) is 25% for the second ink receiving layer (upper layer) and 75 for the first ink receiving layer (lower layer). %.

(Evaluation test)
The following evaluation test was performed on the obtained inkjet recording sheet 1. The results are shown in Table 1 below.

<High-speed wind aptitude (wind unevenness)>
Example 1 Using the slide bead coater, the coating solution A and the coating solution B kept at 30 ° C. on a support laminated with polyethylene at 20 g / m ^{2 on} both sides of a base paper (160 g / m ² ). 190 g / m ^{2 was} applied under the same conditions as those for the coating liquid A and the coating liquid B. Thereafter, high-speed air at 20 ° C. and 10 m / s was sprayed for 1 minute perpendicularly to the coated surface of the support, and then dried at 50 ° C. for 10 minutes. The dried coated surface was evaluated according to the following criteria.
-Evaluation criteria-
○ ・ ・ ・ Dryness unevenness is hardly observed on the coated surface △ ・ ・ ・ Dryness unevenness is slightly observed on the coated surface × ・ ・ ・ Dryness unevenness on the coated surface is conspicuous

<Gloss (image clarity)>
Black solid printing (inkjet recording) was performed on the inkjet recording sheet 1 using an inkjet printer “DryMinilab 400” manufactured by Fujifilm.
The solid image portion of the ink jet recording sheet 1 was measured using the image clarity measuring device ICM-1 (manufactured by Suga Test Instruments Co., Ltd.) based on the image clarity test method defined in JIS H 8686-2. -The image clarity C value (%) was measured under the analysis conditions. The measurement was performed in both the main scanning direction and the sub-scanning direction of printing. Then, the image clarity C value was obtained for each optical comb by the following formula a, and the image clarity C value at each optical comb was added to obtain the sum of image clarity. In the following formula a, M represents the maximum wave height, and m represents the minimum wave height.
Image clarity C value (%) = {(M−m) / (M + m)} × 100 Equation a
<Measurement and analysis conditions>
・ Measurement method: reflection ・ Measurement angle: 60 °
Optical comb: 2.0 mm, 1.0 mm, 0.5 mm, 0.25 mm, 0.125 mm

Based on the obtained measurement results, the following criteria were used for evaluation.
-Evaluation criteria-
◎ ・ ・ ・ 120 or more ○ ・ ・ ・ 80 or more and less than 120 × ・ ・ ・ less than 80

<Brittleness>
The ink jet recording sheet 1 was stored in a constant temperature and humidity room at 10 ° C. and a relative humidity of 20% for 1 day, and then wound around a cylinder to evaluate brittleness. The smaller the diameter of the cylinder, the more easily the ink receiving layer cracks, and the critical cylinder diameter [mm] at which cracking occurs was taken as the brittle value.
The brittleness value is preferably 30 mm, and the allowable range is 40 mm or less.

<Ink absorbability>
Using a Fujifilm ink-jet printer “DryMinlab 400”, perform solid black printing (ink-jet recording) at 80 ° C. at 30 ° C. It observed visually and evaluated based on the following reference | standard.
-Evaluation criteria-
○ ... No transfer at all.
Δ: Slightly transferred.
X: Transfer is remarkable.

<Curl>
The ink jet recording sheet 1 was cut to a width of 8.9 mm and a length (application direction) of 12.7 mm to obtain a sample, which was left to stand at 23 ° C. and 20 RH% for 24 hours. Thereafter, the sample was placed on the desk with the ink receiving layer facing upward, the maximum rising heights at the four corners were measured, and the average value was calculated.
-Evaluation criteria-
×: The ink receiving layer is up and the maximum rising height at the four corners is 10 mm or more. Δ ... The ink receiving layer is up and the maximum rising height at the four corners is 3 to 9 mm.
○ The maximum rising height at the four corners is 0 to 2 mm with the ink receiving layer facing up, and the maximum rising height at the four corners is 0 to 10 mm with the ink receiving layer facing down

<Print density>
Black solid printing (inkjet recording) was performed on the ink receiving layer side (second ink receiving layer surface) of the inkjet recording sheet 1 using an inkjet printer “DryMinilab 400” manufactured by Fujifilm.
The image density of the black (Bk) solid print portion was measured under the conditions of a viewing angle of 2 °, a light source D50, and no filter using “Spectrolino SPM-50” manufactured by Gretag.
The image density is preferably 2.2 or more, and the allowable range is 2.2 or more.

<Overlap unevenness (ΔE (Y))>
Using a Fujifilm ink-jet printer “DryMinilab 400”, yellow solid printing (ink-jet recording) was performed on the ink-receiving layer-forming surface side of the ink-jet recording sheet 1. At that time, the gradation of the image data was adjusted so that the yellow density was about 1.8.
Immediately after printing (within 3 minutes after printing), a part of the yellow part was covered with a glass plate and left for 24 hours. After 24 hours, the hue of the yellow part covered with glass and the hue of the yellow part not covered with glass were each measured with a spectrophotometer, and the difference between these hues was determined as the color difference (ΔE). It was.

From the obtained color difference (ΔE), overlap unevenness (overlapping trace) was evaluated according to the following evaluation criteria.
-Evaluation criteria
○ ... ΔE <9: Unevenness is hardly noticeable Δ ... 9 ≦ ΔE <13: Unevenness is not a problem level × ... 13 ≦ ΔE: Unevenness is a problem level

-Hue measurement conditions-
ΔE was calculated by measuring L, a *, and b * using Spectrolino manufactured by Gretag Macbeth.

[Example 2]
In the same manner as in the preparation of the coating liquid A used in the production of the ink jet recording sheet 1 of Example 1, the dispersion of the vapor phase method silica fine particles was changed from the optimizer to Dinomil KDP (manufactured by Shinmaru Enterprise). A recording sheet 2 was produced. An evaluation test was performed in the same manner as in Example 1 except that the inkjet recording sheet 1 was replaced with the inkjet recording sheet 2.
The dispersion conditions in Dynomill KDP are as follows. The evaluation results are shown in Table 1.
・ Bead diameter 0.65mm
・ Bead filling rate 70%,
・ Peripheral speed 8m / s,
・ Two passes

Example 3
An inkjet recording sheet 3 was prepared in the same manner except that the coating liquid A and the coating liquid B used in the production of the inkjet recording sheet 1 of Example 1 were replaced with the following coating liquid A2 and the following coating liquid B2, respectively. The evaluation test was performed in the same manner as in Example 1 except that the inkjet recording sheet 1 was replaced with the inkjet recording sheet 3. The evaluation results are shown in Table 1 below.

-Preparation of vinyl alcohol solution P2-
A vinyl alcohol solution P2 was prepared in the same manner except that diethylene glycol monobutyl ether (DEGMBE) was replaced with diethylene glycol monohexyl ether (DEGMHE) in the preparation of the vinyl alcohol solution P1.

-Preparation of coating solution A2 and coating solution B2-
A coating solution A2 was prepared in the same manner as in the preparation of the coating solution A, except that the vinyl alcohol solution P2 was used instead of the vinyl alcohol solution P1. Similarly, the coating liquid B2 was prepared in the same manner as in the preparation of the coating liquid B, except that the vinyl alcohol solution P2 was used instead of the vinyl alcohol solution P1.

Example 4
An inkjet recording sheet 4 was prepared in the same manner except that the coating liquid A and the coating liquid B used in the production of the inkjet recording sheet 1 of Example 1 were replaced with the following coating liquid A3 and the following coating liquid B3, respectively. The evaluation test was performed in the same manner as in Example 1 except that the inkjet recording sheet 1 was replaced with the inkjet recording sheet 4. The evaluation results are shown in Table 1 below.

-Preparation of vinyl alcohol solution P3-
A vinyl alcohol solution P3 was prepared in the same manner except that diethylene glycol monobutyl ether (DEGMBE) was replaced with triethylene glycol monobutyl ether (TEGMBE) in the preparation of the vinyl alcohol solution P1.

-Preparation of coating solution A3 and coating solution B3-
A coating solution A3 was prepared in the same manner as in the preparation of the coating solution A, except that the vinyl alcohol solution P3 was used instead of the vinyl alcohol solution P1. Similarly, the coating liquid B3 was prepared in the same manner as in the preparation of the coating liquid B, except that the vinyl alcohol solution P3 was used instead of the vinyl alcohol solution P1.

Example 5
In the production of the ink jet recording sheet 1 of Example 1, in addition to the coating liquid A and the coating liquid B to which the polyaluminum chloride aqueous solution was added, the following coating liquid for forming the glossy layer was applied simultaneously with a slide bead coater. An inkjet recording sheet 5 of Example 5 was obtained in the same manner as Example 1 except that. The inkjet recording sheet 5 thus obtained has a three-layer structure in which a lower layer by the coating liquid A, an upper layer by the coating liquid B, and a glossy expression layer (uppermost layer) by the coating liquid for glossy expression layer formation are formed. .
The coating amount of coating solution A or coating solution B and the polyaluminum chloride aqueous solution is the same as the coating amount in Example 1, and the first ink receiving layer (lower layer) and the second ink receiving layer (upper layer). The second ink-receiving layer (upper layer) is 25% and the first ink-receiving layer (lower layer) is 75%. Further, the moisture application amount of the coating liquid for forming the glossy layer is 12.5 g / m ² (the solid application amount is 1.0 g / m ² , of which the silica solid content application amount is 0.96 g / m 2. ² )

-Preparation of a coating solution for forming a glossy layer-
Colloidal silica (as silica solid content) 100 parts [Snowtex AK-L, manufactured by Nissan Chemical Industries, Ltd., average primary particle size 45 nm]
Polyvinyl alcohol 4 parts [PVA235, manufactured by Kuraray Co., Ltd., saponification degree 88 mol%, average polymerization degree 3,500]
The coating liquid for forming a glossy layer was prepared by mixing colloidal silica having the above composition and polyvinyl alcohol, and having a solid content concentration of 8% with ion-exchanged water.

  The evaluation test was performed in the same manner as in Example 1 except that the inkjet recording sheet 1 was replaced with the inkjet recording sheet 5. The evaluation results are shown in Table 1 below.

[Comparative Example 1]
An inkjet recording sheet 6 was prepared in the same manner as in the production of the inkjet recording sheet 1 of Example 1, except that the coating liquid A was replaced with the coating liquid A4 and the coating liquid B was replaced with the coating liquid B4.
Coating solution A4 was prepared in the same manner as coating solution A except that “JM33” in coating solution A was changed to “PVA235” (manufactured by Kuraray Co., Ltd., saponification degree 88 mol%, average polymerization degree 3,500). Prepared. Similarly, the coating liquid B4 was prepared in the same manner as in the preparation of the coating liquid B except that “JM33” in the coating liquid B was changed to the “PVA235”.

  The evaluation test was performed in the same manner as in Example 1 except that the inkjet recording sheet 1 was replaced with the inkjet recording sheet 6. The evaluation results are shown in Table 1 below.

[Comparative Example 2]
Inkjet recording was carried out in the same manner as in the production of the inkjet recording sheet 1 of Example 1, except that the amount of zircozole “ZA-30” (50% aqueous solution) in the coating solution B was changed from 2.8 parts to 7 parts. Sheet 7 was prepared.
The evaluation test was performed in the same manner as in Example 1 except that the inkjet recording sheet 1 was replaced with the inkjet recording sheet 7. The evaluation results are shown in Table 1 below.

[Comparative Example 3]
An ink jet recording sheet 8 was prepared in the same manner except that the coating liquid A used in the preparation of the ink jet recording sheet 1 of Example 1 was replaced with the following coating liquid A5, and the ink jet recording sheet 1 was used as the ink jet recording sheet. The evaluation test was performed in the same manner as in Example 1 except that the number was changed to 8. The evaluation results are shown in Table 1 below.

-Preparation of vinyl alcohol solution P4-
A vinyl alcohol solution P4 was prepared in the same manner as in the preparation of the vinyl alcohol solution P1, except that 134 parts of diethylene glycol monobutyl ether (DEGMBE) was changed to 67 parts.

-Preparation of coating liquid A5-
A coating solution A5 was prepared in the same manner as in the preparation of the coating solution A, except that the vinyl alcohol solution P4 was used instead of the vinyl alcohol solution P1.

[Comparative Example 4]
In the production of the ink jet recording sheet 1 of Example 1, the ink receiving layer was formed in the same manner except that the coating liquid A for forming the first ink receiving layer (lower layer) and the polyaluminum chloride aqueous solution were not applied. A single-layer inkjet recording sheet 9 was produced.
In addition, each coating amount of the coating liquid B and the polyaluminum chloride aqueous solution is as follows.
And coating liquid B ··· 165g / ^{m 2}
・ 4.6% polyaluminum chloride aqueous solution 11.4 g / m ²
[Daiming Chemical Co., Ltd., Alpha-in 83, aluminum salt]

  The evaluation test was performed in the same manner as in Example 1 except that the inkjet recording sheet 1 was replaced with the inkjet recording sheet 9. The evaluation results are shown in Table 1 below.

[Comparative Example 5]
In the production of the ink jet recording sheet 1 of Example 1, the ink receiving layer was similarly formed except that the coating liquid B for forming the second ink receiving layer (upper layer) and the polyaluminum chloride aqueous solution were not applied. A single-layer inkjet recording sheet 10 was produced.
In addition, each coating amount of the coating liquid A and the polyaluminum chloride aqueous solution is as follows.
・ Coating liquid B: 165 g / m ²
・ 4.6% polyaluminum chloride aqueous solution 11.4 g / m ²
[Daiming Chemical Co., Ltd., Alpha-in 83, aluminum salt]

  The evaluation test was performed in the same manner as in Example 1 except that the inkjet recording sheet 1 was replaced with the inkjet recording sheet 10. The evaluation results are shown in Table 1 below.

[Comparative Example 6]
An inkjet recording sheet 11 was prepared in the same manner except that the coating liquid A used in the preparation of the inkjet recording sheet 1 of Example 1 was replaced with the following coating liquid A6 and the coating liquid B was replaced with the following coating liquid B5. The evaluation test was performed in the same manner as in Example 1 except that the inkjet recording sheet 1 was replaced with the inkjet recording sheet 11. The evaluation results are shown in Table 1 below.

-Preparation of coating solution B5-
A coating solution B5 was prepared in the same manner as in the preparation of the coating solution B, except that 2.8 parts of zircozole “ZA-30” (50% aqueous solution) was replaced with 7 parts.

-Preparation of coating liquid A6-
A coating solution A6 was prepared in the same manner except that 14.0 parts of zircozole “ZA-30” (50% aqueous solution) was replaced with 7 parts.

[Comparative Example 7]
The inkjet recording sheet 12 was prepared in the same manner except that the coating liquid A used in the preparation of the inkjet recording sheet 1 of Example 1 was replaced with the following coating liquid A7 and the coating liquid B was replaced with the following coating liquid B6. Tried. However, the coating liquid B6 for forming the second ink receiving layer (upper layer) was thickened and gelled, and the ink jet recording sheet 12 could not be obtained. Therefore, the evaluation test was not performed, and is shown as “-” in Table 1 below.

-Preparation of vinyl alcohol solution P5-
A vinyl alcohol solution P5 was prepared in the same manner as in the preparation of the vinyl alcohol solution P1, except that 134 parts of diethylene glycol monobutyl ether (DEGMBE) was changed to 44.7 parts.

-Preparation of coating solution B6-
A coating solution B6 was prepared in the same manner as in the preparation of the coating solution B, except that the polyvinyl alcohol solution P1 was replaced with the polyvinyl alcohol solution P5.

-Preparation of coating solution A7-
A coating solution A7 was prepared in the same manner as in the preparation of the coating solution A, except that 33.5 parts of diethylene glycol monobutyl ether was replaced with 67 parts of diethylene glycol monobutyl ether.

The ink jet recording sheets of Examples 1 to 5 and Comparative Examples 1 to 7 all have a layer thickness ratio between the first ink receiving layer (lower layer) and the second ink receiving layer (upper layer). Are composed of 75% and 25%, respectively.
The components contained in the ink receiving layers of Examples 1 to 5 and Comparative Examples 1 to 7, the silica dispersion model used, and each coating liquid (coating liquid A to coating liquid A7, coating liquid B to coating liquid) The particle size (average secondary particle size) of the silica fine particles in B6) is shown in Table 1 below. The particle size (average secondary particle size) of the silica fine particles was measured using a laser diffraction particle size distribution measuring device “LA700” manufactured by Horiba, Ltd.

In Table 1, “PVA type saponification degree / mol%” is the type of PVA used in the upper stage, and the lower stage is the saponification degree (mol%) of the PVA.
“Zr salt amount (vs. silica)” is the content of the water-soluble zirconium salt in the first ink receiving layer relative to the vapor phase silica fine particles in the first ink receiving layer in the first ink receiving layer column. In the second ink receiving layer column, the content (% by mass) of the high-boiling organic solvent in the second ink receiving layer with respect to the vapor phase method silica fine particles in the second ink receiving layer. Represents.
In the “high boiling point solvent type / silica”, the upper part represents the kind of the high boiling point organic solvent, and the lower part represents the gas phase method silica fine particles in the first ink receiving layer in the first ink receiving layer column. This represents the content (% by mass) of the high-boiling organic solvent in the first ink-receiving layer. In the second ink-receiving layer column, the second ink with respect to the vapor phase method silica fine particles in the second ink-receiving layer. Represents the content (% by mass) of the high-boiling organic solvent in the receiving layer.

From Table 1, Comparative Examples 1 to 7 which do not satisfy the constituent requirements of the present invention are the implementation of the present invention in any one of high-speed wind suitability, image clarity, brittleness, ink absorbability, curl, print density, and overlay unevenness. Evaluation was inferior compared with Examples 1-5, and high-speed wind suitability, image clarity, brittleness, ink absorptivity, curl, print density, and overlay unevenness could not be achieved. Particularly in Comparative Example 2, Comparative Example 3, and Comparative Example 6, since the wind unevenness of the coated sample was large and a sample worthy of evaluation could not be obtained, image clarity, brittleness, ink absorptivity, curl, print density, and overlay unevenness. The evaluation test could not be performed.
On the other hand, in Examples 1 to 5, it was found that high-speed wind suitability and image clarity, brittleness, ink absorbability, curl, print density, and overlay unevenness can be compatible, and various problems can be solved. .

Claims (7)

A first ink receiving layer containing, on the non-absorbing support, in order from the non-absorbing support side, vapor-phase process silica, polyvinyl alcohol having a saponification degree of 90 mol% or more, a boron compound, and a water-soluble zirconium salt; A gas phase method silica, a polyvinyl alcohol having a saponification degree of 90 mol% or more, a boron compound, and a second ink receiving layer containing a water-soluble organic solvent having a boiling point of 120 ° C. or more,
The content of the water-soluble zirconium salt in the second ink receiving layer is less than the content of the water-soluble zirconium salt in the first ink receiving layer, and the second ink receiving layer is water-soluble. When the zirconium salt is contained, the content of the water-soluble zirconium salt in the second ink receiving layer is 0.6% by mass or less with respect to the content of the vapor phase silica in the second ink receiving layer. And
The content of the water-soluble organic solvent having a boiling point of 120 ° C. or higher in the first ink receiving layer is less than the content of the water-soluble organic solvent having a boiling point of 120 ° C. or higher in the second ink receiving layer, When the first ink receiving layer contains a water-soluble organic solvent having a boiling point of 120 ° C. or higher, the content of the water-soluble organic solvent having a boiling point of 120 ° C. or higher in the first ink receiving layer is An ink jet recording medium having a mass of 2% by mass or less based on the content of vapor phase silica in the first ink receiving layer.   The inkjet recording medium according to claim 1, wherein the water-soluble organic solvent having a boiling point of 120 ° C or higher is dialkylene glycol monoalkyl ether.   The inkjet recording medium according to claim 1, wherein the water-soluble organic solvent having a boiling point of 120 ° C. or higher is diethylene glycol monobutyl ether.   The inkjet recording medium according to any one of claims 1 to 3, further comprising a glossy layer containing colloidal silica at a position farthest from the non-absorbing support. On the non-absorbable support, coating solution A containing vapor-phase method silica, polyvinyl alcohol having a saponification degree of 90 mol% or more, a boron compound, and a water-soluble zirconium salt, vapor-phase method silica, and saponification degree 90 mol. % Coating solution B containing polyvinyl alcohol, boron compound, and water-soluble organic solvent having a boiling point of 120 ° C. or higher is simultaneously applied in layers so that the coating solution B overlaps the coating solution A. And forming an ink receiving layer,
When the content of the water-soluble zirconium salt in the coating liquid B is less than the content of the water-soluble zirconium salt in the coating liquid A and the coating liquid B contains a water-soluble zirconium salt, The content of the water-soluble zirconium salt in the coating liquid B is 0.6% by mass or less with respect to the content of the vapor phase silica in the coating liquid B,
The content of the water-soluble organic solvent having a boiling point of 120 ° C. or higher in the coating liquid A is less than the content of the water-soluble organic solvent having a boiling point of 120 ° C. or higher in the coating liquid B, and the coating liquid When A contains a water-soluble organic solvent having a boiling point of 120 ° C. or higher, the content of the water-soluble organic solvent having a boiling point of 120 ° C. or higher in the coating solution A is contained in the vapor phase silica in the coating solution A. The manufacturing method of the inkjet recording medium which is 2 mass% or less with respect to quantity.   6. The ink jet recording according to claim 5, wherein the coating liquid B contains gas phase method silica dispersed by a high pressure disperser of 30 MPa to 300 MPa, and the coating solution A contains gas phase method silica dispersed using beads. A method for manufacturing a medium.   The average secondary particle diameter of the silica fine particles of the vapor phase silica contained in the coating liquid A is 100 nm to 170 nm, and the average secondary particle diameter of the silica fine particles of the vapor phase silica contained in the coating liquid B is 6. The method for producing an ink jet recording medium according to claim 5, wherein the method is 80 nm to 130 nm.