JP2005212358A - Inkjet recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording medium, in which both the developments of bleeding with time and of bronzing luster are effectively suppressed. <P>SOLUTION: This inkjet recording medium has an ink accepting layer including fine particles, a water-soluble resin, a crosslinker, a mordant and a metal salt compound on a support. The metal salt compound includes at least one of a zirconium compound and an aluminum compound and, at the same time, when a resin film with the thickness of 5 μm is formed out of the constituent elements included in the ink accepting layer except the fine particles, the time required until the swelling coefficient measured with a swelling degree meter reaches minus 50% from the time that 0.2 g of a mixed solution consisting of 67.5 mass% of water, 8 mass% of glycerol, 6.5 mass% of triethylene glycol, 3 mass% of 2-pyrrolidone, 8.5 mass% of triethylene glycol monobutyl ether and 6.5 mass% of triethanolamine is dropped on the resin film is at least 100 s. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an ink jet recording medium, and more particularly to an ink jet recording medium in which the occurrence of bronze gloss is suppressed.

  In recent years, with the rapid development of the information technology (IT) industry, various information processing systems have been developed, and a recording method and a recording apparatus suitable for each information processing system have been developed and put into practical use. Among such recording methods, the inkjet recording method is advantageous in that it can be recorded on various recording materials, the hardware (device) is relatively inexpensive, compact, and low in noise. It has been widely used not only in offices but also in home use.

  In recent years, it has become possible to obtain a so-called photographic-like high-quality recorded material as the resolution of an ink jet printer increases. As described above, with the further development of the hardware (device) surface, various improvements have been made to the recording sheet for ink jet recording.

The characteristics required for a recording sheet for ink jet recording are generally (1) fast drying (fast ink absorption speed), and (2) proper and uniform ink dot diameter (bleeding). (3) Good graininess, (4) High roundness of dots, (5) High color density, (6) High saturation (no dullness) ), (7) The light resistance and water resistance of the print portion are good, (8) The whiteness of the recording sheet is high, (9) The recording sheet has good storage stability (yellowing coloration during long-term storage) (10) hard to deform, good dimensional stability (curl is sufficiently small), (11) good running performance of hardware, Etc.
Furthermore, in the use of photo glossy paper used for the purpose of obtaining so-called photographic-like high-quality recorded matter, in addition to the above properties, glossiness, surface smoothness, texture of photographic paper similar to silver salt photography, etc. are required. Is done.

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

  For example, there has been proposed an ink jet recording medium containing fine inorganic pigment particles and a water-soluble resin and having an ink receiving layer having a high porosity on a support (for example, see Patent Documents 1 and 2). These recording media, particularly ink jet recording media provided with an ink receiving layer having a porous structure using silica as inorganic pigment fine particles, are excellent in ink absorbability (hereinafter also referred to as “ink receiving ability”) due to the structure. In addition, it has a high ink receptivity capable of forming a high-resolution image and can exhibit high gloss.

However, even in an ink jet recording medium having a high ink receptive capacity, the dye in the ink may form a film near the surface of the ink receptive layer after ink jet recording. As described above, when the dye is formed into a film, the reflected light causes so-called “bronze gloss” in which the gloss of the metallic tone becomes metallic. Therefore, development of an ink jet recording medium that suppresses the occurrence of such bronze gloss has been desired.
JP-A-10-119423 Japanese Patent Laid-Open No. 10-217601

  SUMMARY OF THE INVENTION An object of the present invention is to provide an ink jet recording medium that effectively suppresses occurrence of aging blur and bronze gloss in order to solve the above-described problems.

The above problem is solved by the following means.
<1> An inkjet recording medium having an ink receiving layer containing fine particles, a water-soluble resin, a crosslinking agent, a mordant, and a metal salt compound on a support, wherein the metal salt compound is at least one of a zirconium compound and an aluminum compound When a resin film having a thickness of 5 μm is formed with the constituent elements contained in the ink receiving layer excluding the fine particles, water is 67.5% by mass, glycerin is 8% by mass, and triethylene glycol is 6.5% by mass. %, 2-pyrrolidone 3% by weight, triethylene glycol monobutyl ether 8.5% by weight and triethanolamine 6.5% by weight of a mixed solution was dropped 0.2 g on the resin film, The ink jet recording is characterized in that the time until the swelling ratio measured by the meter becomes minus 50% is 100 seconds or more. It is a medium.

<2> The ink-receiving layer forms a coating layer by coating a coating liquid containing the fine particles, the water-soluble resin, the mordant, and the metal salt compound on the support, and the coating The basic solution is applied simultaneously with the formation of the coating layer by applying a liquid, or while the coating layer formed by applying the coating liquid is in the process of drying and before the coating liquid exhibits reduced-rate drying. The inkjet recording medium according to <1>, wherein the inkjet recording medium is formed by being applied to the coating layer, and the crosslinking agent is contained in at least one of the coating solution and the basic solution.
<3> The inkjet recording medium according to <1> or <2>, wherein the crosslinking agent contains a boron compound.

  <4> The inkjet recording medium according to <1> to <3>, wherein the crosslinking agent is contained in the basic solution.

  <5> The inkjet recording medium according to <2> to <4>, wherein the basic solution contains borax as the crosslinking agent.

<6> The above <1> to <5>, wherein the crosslinking agent contains at least borax, and the coating amount of the borax in the ink receiving layer is 0.07 to 0.3 g / m ² . An inkjet recording medium.

  According to the present invention, it is possible to provide an ink jet recording medium that effectively suppresses occurrence of aging blur and bronze gloss.

<Inkjet recording medium>
An inkjet recording medium having an ink receiving layer containing fine particles, a water-soluble resin, a crosslinking agent, a mordant, and a metal salt compound on a support, wherein the metal salt compound contains at least one of a zirconium compound and an aluminum compound. In addition, when a resin film having a thickness of 5 μm is formed from the components included in the ink receiving layer excluding the fine particles, water is 67.5% by mass, glycerin is 8% by mass, triethylene glycol is 6.5% by mass, -0.2 g of a mixed solution composed of 3% by mass of pyrrolidone, 8.5% by mass of triethylene glycol monobutyl ether and 6.5% by mass of triethanolamine was dropped on the resin film, and then measured with a swelling meter. The time until the swelling rate to be reduced to minus 50% (hereinafter sometimes simply referred to as “dissolution time”) is 100 seconds or more. Characterized in that there.

  In the ink jet recording medium of the present invention, since the dissolution time is 100 seconds or more, the polymer film contained in the ink receiving layer is strong, and after ink jet recording, the dye forms a film and bronze gloss occurs. Can be suppressed.

  Here, “the constituents contained in the ink receiving layer excluding the fine particles” means the same composition (type, mixing ratio) as that contained in the ink receiving layer coating liquid used when forming the ink receiving layer. Water-soluble resin, cross-linking agent, mordant, metal salt compound, dispersant, and other additives contained in the ink receiving layer excluding the fine particles.

  In the present invention, the dissolution time is 100 seconds or longer, preferably 200 seconds or longer, and more preferably 250 seconds. If the dissolution time is less than 100 seconds, the occurrence of bronze gloss cannot be effectively suppressed. This is because when the ink is deposited on the ink receiving layer, if the polymer (water-soluble resin) of the ink receiving layer is eluted in the ink solvent that has been deposited, the dye in the ink will aggregate in the ink solvent. It is estimated that. That is, when the dye aggregates in the ink solvent, it becomes impossible to absorb the dye that is subjected to multiple droplets, and the dye concentrates on the surface of the recording surface, thereby causing bronze gloss. For this reason, if the said dissolution time is long, it is estimated that the elution of a polymer is reduced and generation | occurrence | production of bronze gloss can be suppressed.

In the present invention, in order to increase the dissolution time of the ink receiving layer to 100 seconds or more, for example, borax is used as the cross-linking agent, and the coating amount is 0.07 to 0.3 g / m ^2. Is preferred. When the coating amount is in the range of 0.07 to 0.3 g / m ² , the curing of the water-soluble resin contained in the ink receiving layer can be strengthened, so the dissolution time can be set to 100 seconds or more. It becomes possible.

The dissolution time is the time from when 0.2 g of the mixed solution is dropped on the resin coating until the swelling ratio measured by a swelling meter becomes minus 50%. The swelling ratio can be measured with a swelling meter described below. Further, the upper limit of the dissolution time is not particularly limited. However, when the dissolution time is adjusted by the coating amount of borax, if the coating amount of borax exceeds 0.3 g / m ² , aging blurring deteriorates. Therefore, it is preferable to use borax within the above range.

  The swelling meter according to the present invention will be described with reference to FIG. FIG. 1 is a schematic diagram for explaining a swelling meter according to the present invention. In FIG. 1, the swelling meter 10 includes a stylus 12, a thickness displacement measuring instrument 14, and a CPU 16. Moreover, the sample 18 is comprised from the resin film 20 and the support body 22, and the mixed solution 24 is dripped. In the present invention, the swell meter 10 moves the stylus 12 in the direction of arrow A at regular intervals so that the tip of the stylus 12 is brought into contact with the surface of the resin film 20 of the sample 18, thereby increasing the thickness of the resin film 20. It is an apparatus that measures the displacement and calculates the swelling ratio of the resin coating 20 based on the displacement of the thickness.

  The stylus 12 has a cylindrical shape with a diameter of 8 mm, and has a hemispherical tip. The stylus 12 can be made of quartz glass. The stylus 12 is brought into contact with the sample in the direction of arrow A shown in FIG. For example, the swelling rate can be measured by bringing the stylus 12 into contact with the resin coating 20 at intervals of 4 seconds, for example.

  The resin coating 20 is a water-soluble resin, a cross-linking agent, a mordant, a dispersant, a metal having the same composition (type and mixing ratio) as that contained in the ink-receiving layer coating liquid used when forming the ink-receiving layer in the present invention. It is a layer formed using a salt compound and an additive other than the fine particles contained in the ink receiving layer. The resin coating 20 is formed so as to have a thickness of 5 μm.

  The mixed solution 24 is composed of 67.5% by mass of water, 8% by mass of glycerin, 6.5% by mass of triethylene glycol, 3% by mass of 2-pyrrolidone, 8.5% by mass of triethylene glycol monobutyl ether, and 6.5% triethanolamine. It is comprised by the mass%, and 0.2g is dripped on the resin film 20. FIG. The mixed solution 24 can be prepared by mixing the constituent components and then mixing them.

The thickness displacement measuring instrument 14 measures the displacement from the original thickness (L ⁰ ) of the resin coating 22 by the displacement of the potential of the stylus 12. The CPU 16 calculates the swelling rate of the resin film according to the following formula based on the thickness displacement measured by the thickness displacement measuring instrument 14.
Swelling ratio (%) = (L ¹ −L ⁰ ) × 100 / L ⁰ Formula [L ¹ : Total thickness of swollen resin film, L ⁰ : Original thickness of resin film (thickness before swelling)]

  In the present invention, the dissolution time is a time from when the mixed solution 24 is dropped onto the resin coating 20 until the swelling ratio becomes minus 50%. FIG. 2 shows the time after the above-mentioned mixed solution was dropped on the surface of the resin film as the degree of swelling measured by the swelling watch 10 in the present invention. As can be seen from FIG. 2, after the mixed solution is dropped, the swelling rate of the resin film increases once and then decreases. The dissolution time in the present invention is a time (a time represented by an arrow C in FIG. 2) until the swelling rate becomes minus 50% (point B in FIG. 2). Means about half dissolved.

  Hereinafter, the configuration of the ink jet recording medium of the present invention will be described in detail.

<Ink receiving layer>
The ink receiving layer in the present invention contains at least fine particles, a water-soluble resin, a mordant, and a metal chloride, and other additives and the like can be added as necessary.

(Fine particles)
The ink receiving layer in the invention contains fine particles, and the fine particles may be inorganic fine particles or organic fine particles, but are preferably inorganic fine particles.
As the inorganic fine particles, inorganic pigment fine particles are suitable. Examples of the inorganic pigment fine particles include silica fine particles, colloidal silica, titanium dioxide, barium sulfate, calcium silicate, zeolite, kaolinite, halloysite, mica, talc, carbonic acid. Calcium, magnesium carbonate, calcium sulfate, boehmite, pseudoboehmite and the like can be mentioned, and silica fine particles are particularly preferable from the viewpoint of ink absorbability and high color developability.

  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 performed to an appropriate fine particle diameter, transparency can be imparted to the ink receiving layer. There is an advantage that high color density and good color developability can be obtained. The transparency of the ink-receiving layer as described above means that high color density and good color developability not only for applications that require transparency such as OHP, but also for recording sheets such as photo glossy paper. And it is important from the viewpoint of obtaining glossiness.

  The average primary particle diameter of the inorganic pigment 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.

  In particular, the silica fine particles have a silanol group on the surface thereof, and the particles easily adhere to each other by hydrogen bonding of the silanol group, and also have an adhesion effect between the particles via the silanol group and the water-soluble resin. Thus, when the average primary particle size 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.

  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.

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 agglomerate closely (aggregate). In the case of the method silica, the density of silanol groups on the surface of the fine particles is as small as ² to 3 / nm ² , so that it becomes sparse soft agglomeration (flocculate), and as a result, it is estimated that the structure has a high porosity. The
In the present invention, vapor phase silica fine particles (anhydrous silica) obtained by the dry method are preferable, and silica fine particles having a density of 2 to 3 silanol groups / nm ² on the surface of the fine particles are more preferable.

  The organic fine particles are preferably polymer fine particles obtained by emulsion polymerization, microemulsion polymerization, soap-free polymerization, seed polymerization, dispersion polymerization, etc., specifically, polyethylene, polypropylene, polystyrene, polyacrylate, polyamide, silicon resin. , Phenol resin, natural polymer powder, latex or emulsion polymer fine particles.

(Water-soluble resin)
The ink receiving layer in the present invention contains a water-soluble resin. As the water-soluble resin, polyvinyl alcohol resins, water-soluble cellulose resins, resins having an ether bond, resins having a carbamoyl group, resins having a carboxyl group, and gelatins are preferably used.
By adding a water-soluble resin, the ink receiving layer can be prevented from cracking. Also, by adding a water-soluble resin, a porous structure having a high porosity can be formed with the fine particles and the like, and the ink receiving ability of the ink receiving layer can be improved.

  The polyvinyl alcohol-based resin can be appropriately selected from known ones. For example, polyvinyl alcohol (PVA), a cation-modified polyvinyl alcohol, and an anion-modified resin having a hydroxyl group as a hydrophilic structural unit. And polyvinyl alcohol derivatives such as polyvinyl alcohol, silanol-modified polyvinyl alcohol, and polyvinyl acetal.

  The number average polymerization degree of the polyvinyl alcohol (PVA) is preferably 1800 or more, and more preferably 2000 or more, from the viewpoint of preventing cracks. Moreover, when combining the said water-soluble resin with a silica fine particle, the kind of water-soluble resin becomes important from a transparency viewpoint. In particular, when anhydrous silica is used, it is preferable to contain PVA as one of the water-soluble resins. The saponification degree of the polyvinyl alcohol is preferably 99% or less, preferably 60 to 99%, particularly preferably 70 to 99% from the viewpoint of forming a three-dimensional network structure.

  The polyvinyl alcohol may be used alone or in combination of two or more.

  The PVA has a hydroxyl group in its structural unit, and this hydroxyl group and a 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. It is considered that an ink receiving layer having a porous structure with a high porosity can be formed by forming such a three-dimensional network structure.

  The cellulose resin can be appropriately selected from known ones. For example, methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC), hydroxypropyl cellulose (HPC) ), Hydroxypropyl methylcellulose (HPMC) and the like, and from the viewpoint of aging blur of the image, among them, methylcellulose (MC), hydroxyethylcellulose (HEC), hydroxypropylcellulose (HPC), hydroxypropylmethylcellulose (HPMC) are preferable, Furthermore, hydroxypropylcellulose (HPC) and hydroxypropylmethylcellulose (HPMC) are preferable.

  The cellulosic resin has a hydroxyl group in its structural unit, and this hydroxyl group and a silanol group on the surface of the silica fine particle form a hydrogen bond to form a three-dimensional network structure in which the secondary particle of the silica fine particle is a chain unit. Make it easy to do. It is considered that an ink receiving layer having a porous structure with a high porosity can be formed by forming such a three-dimensional network structure. In addition, it has a function of adjusting aging blur of the color material.

  The hydrophilic resin having an ether bond can be appropriately selected from known ones. For example, polyethylene oxide (PEO), polypropylene oxide (PPO), polyethylene glycol (PEG), polyvinyl ether (PVE) Etc.

  The resin having a carbamoyl group includes a resin having a hydrophilic amide group or an amide bond, and can be appropriately selected from known ones. Polyacrylamide (PAAM), polyvinylpyrrolidone ( PVP) and the like.

  The resin having a carboxyl group as the dissociable group can be appropriately selected from known ones, and examples thereof include polyacrylates, maleic resins, alginates, and gelatins. Furthermore, chitins, chitosans and starch can be mentioned.

The total content of the water-soluble resin is to prevent a decrease in film strength and cracking during drying due to an insufficient content, and due to an excessive content, the voids are easily blocked by the resin. From the viewpoint of preventing the ink porosity from decreasing due to a decrease in the porosity, the amount is preferably 9 to 40% by mass, and more preferably 12 to 33% by mass with respect to the total solid mass of the ink receiving layer.
The fine particles and the water-soluble resin mainly constituting the ink receiving layer may be a single material or a mixed system of a plurality of materials.
In particular, in the case of using the cellulose-based resin, the total content in the ink receiving layer of the cellulose resin, preferably ^{0.1~3.0g / m 2, 0.2~1.0g / m} 2 and more preferable. The total amount thereof is in the range of ^{0.1g / m 2 ~3.0g / m 2} , water resistance of the ink jet recording medium, the with lapse time blurring of the image can be sufficiently increased in a high humidity, Moreover, beading can be suppressed.

When the water-soluble resin is used in combination with at least two or more selected from polyvinyl alcohol resin, cellulose resin, resin having ether bond, resin having carbamoyl group, resin having carboxyl group and gelatins The total content thereof is preferably contained within ^{2 to} 8 g / m ² of the ink receiving layer.

  Among the water-soluble resins, polyvinyl alcohol (PVA) resins and cellulose resins are more preferable. These can be used alone or in combination, but it is more preferable to use a polyvinyl alcohol (PVA) resin and a cellulose resin in combination.

  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 fine particles to water-soluble resin)
The content ratio of the fine particles (preferably silica fine particles; x) to the water-soluble resin (y) [PB ratio (x / y), the mass of inorganic pigment fine particles relative to 1 part by mass of the water-soluble resin] is the film structure of the ink receiving layer. It also has a big impact. 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 recording sheet when passing through the conveyance system of the ink jet printer, the ink receiving layer needs to 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 a water-soluble resin are completely dispersed in an aqueous solution with a PB ratio (x / y) of 2/1 to 5/1 is coated on a support. When the coating layer is dried, a three-dimensional network structure in which the 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%, and the pore specific volume is 0. A translucent porous film having a surface area of 5 ml / g or more and a specific surface area of 100 m ² / g or more can be easily formed.

(Crosslinking agent)
The ink receiving layer in the present invention is a porous layer containing fine particles, a water-soluble resin, and a crosslinking agent capable of crosslinking the water-soluble resin, and cured by a crosslinking reaction of the water-soluble resin with the crosslinking agent.

As the cross-linking agent, a suitable one may be appropriately selected in relation to the water-soluble resin contained in the ink-receiving layer. Among them, a boron compound is preferable in that the cross-linking reaction is rapid, and examples thereof include borax and boric acid. , borates (eg, _{orthoborate, InBO 3, ScBO 3, YBO} 3, LaBO 3, Mg 3 (BO 3) 2, Co 3 (BO 3) 2, two borates (e.g., Mg ₂ B ₂ O ₅ , Co ₂ B ₂ O ₅ ), metaborates (eg, LiBO ₂ , Ca (BO ₂ ) ₂ , NaBO ₂ , KBO ₂ ), tetraborate (eg, Na ₂ B ₄ O ₇ .10H ₂ O), And pentaborates (for example, KB ₅ O ₈ .4H ₂ O, Ca ₂ B ₆ O ₁₁ .7H ₂ O, CsB ₅ O ₅ ), etc. Of these, boric acid, borax and borates are preferred, and the dissolution time in the present invention In order to increase the curing of the water-soluble resin in order to make the time of 100 seconds or longer, it is particularly preferable to use borax.

  In the present invention, the crosslinking agent is preferably contained in an amount of 0.02 to 0.50 parts by mass, and 0.04 to 0.30 parts by mass with respect to 1.0 part by mass of the water-soluble resin. More preferably. When the content of the crosslinking agent is within the above range, the water-soluble resin can be effectively crosslinked to prevent cracks and the like.

When borax is used as the crosslinking agent, the coating amount of the borax in the ink receiving layer is preferably 0.07 to 0.3 g / m ² , and 0.08 to 0.28 g / m ^2. m ² is more preferable. When the coating amount of the borax is in the range of 0.07 to 0.3 g / m ² , the water-soluble resin can be hardened and the dissolution of the water-soluble resin into the ink solvent can be suppressed. .

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 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.

The crosslinking agent can be suitably applied as follows. Here, a case where borax is used as a crosslinking agent will be described as an example.
When the ink receiving layer is a layer obtained by crosslinking and curing the coating layer coated with the coating solution for the ink receiving layer (first coating solution), the crosslinking curing is performed by (1) forming the coating layer by coating the coating solution. At the same time, (2) at any time during the dry coating of the coating layer formed by coating the coating solution and before the coating layer exhibits reduced drying, for example, a basic pH of 8 or more This is performed by applying a solution (second coating solution) to the coating layer. Borax, which is a cross-linking agent, may be contained in either the first coating solution or the second coating solution, and may be contained in both the first coating solution and the second coating solution.
It is preferable that boric acid or the like is included in the ink receiving layer coating solution, and borax is included in the basic solution.

(mordant)
In the present invention, a mordant can be contained in the ink receiving layer in order to improve the water resistance and aging resistance of the formed image. As the mordant, any of an organic mordant such as a cationic polymer (cationic mordant) and an inorganic mordant such as a water-soluble metal compound can be used. As the mordant, either an organic mordant or an inorganic mordant can be used. These mordants shall mean things other than the water-soluble metal salt compound mentioned later. Of these, organic mordants are preferable, and cationic mordants are particularly preferable.

  The presence of the mordant in at least the upper layer of the ink receiving layer causes an interaction with an ink-jet liquid ink having an anionic dye as a coloring material, which stabilizes the coloring material, thereby improving water resistance and resistance. The aging blur can be further improved.

  In this case, the ink receiving layer coating liquid (first coating liquid) and the basic solution (second coating liquid) may be contained, but a liquid containing inorganic fine particles (particularly, vapor phase silica) Is preferably contained in a second coating liquid that is a separate liquid. That is, when a mordant is added directly to a coating solution for an ink receiving layer, aggregation may occur in the presence of vapor phase silica having an anionic charge. Can be prepared independently and applied separately, there is no need to worry about agglomeration of inorganic fine particles, and the range of mordant species can be selected.

  Among these, it is particularly preferable to use a basic mordant (for example, polyallylamine). When a basic mordant is used, it plays a role as a mordant and also functions as a basic substance, and a basic solution can be prepared without using a basic substance.

As the cationic mordant, a polymer mordant having a primary to tertiary amino group or a quaternary ammonium base as a cationic group is preferably used, but a cationic non-polymer mordant may also be used. it can.
Examples of the polymer mordant include a homopolymer of a monomer having a primary to tertiary amino group and a salt thereof, or a monomer having a quaternary ammonium base (hereinafter referred to as “mordant monomer”), or the mordant monomer. It is preferable to obtain a copolymer or a condensation polymer of the monomer and other monomers (hereinafter referred to as “non-mordant polymer”). These polymer mordants can be used in any form of a water-soluble polymer or water-dispersible latex particles.

  Examples of the mordant monomer include trimethyl-p-vinylbenzylammonium chloride, trimethyl-m-vinylbenzylammonium chloride, triethyl-p-vinylbenzylammonium chloride, triethyl-m-vinylbenzylammonium chloride, N, N-dimethyl- N-ethyl-Np-vinylbenzylammonium chloride, N, N-diethyl-N-methyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-Nn-propyl-Np-vinylbenzyl Ammonium chloride, N, N-dimethyl-Nn-octyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N-benzyl-Np-vinylbenzylammonium chloride, N, N-diethyl-N Benzyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N- (4-methyl) benzyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N-phenyl-Np-vinyl Benzylammonium chloride;

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

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

  Specific examples of the compound include monomethyl diallylammonium chloride, trimethyl-2- (methacryloyloxy) ethylammonium chloride, triethyl-2- (methacryloyloxy) ethylammonium chloride, trimethyl-2- (acryloyloxy) ethylammonium chloride, Triethyl-2- (acryloyloxy) ethylammonium chloride, trimethyl-3- (methacryloyloxy) propylammonium chloride, triethyl-3- (methacryloyloxy) propylammonium chloride, trimethyl-2- (methacryloylamino) ethylammonium chloride, triethyl- 2- (methacryloylamino) ethylammonium chloride, trimethyl-2- (acryloylua) C) ethylammonium chloride, triethyl-2- (acryloylamino) ethylammonium chloride, trimethyl-3- (methacryloylamino) propylammonium chloride, triethyl-3- (methacryloylamino) propylammonium chloride, trimethyl-3- (acryloylamino) Propylammonium chloride, triethyl-3- (acryloylamino) propylammonium chloride;

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

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

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

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

  Furthermore, as a polymer mordant, polydiallyldimethylammonium chloride, polymethacryloyloxyethyl-β-hydroxyethyldimethylammonium chloride, polyethyleneimine, polyallylamine and its modified product, polyallylamine hydrochloride, polyamide-polyamine resin, cationized starch, Dicyandiamide formalin condensate, dimethyl-2-hydroxypropylammonium salt polymer, polyamidine, polyvinylamine, or acrylic silicon described in JP-A-10-264511, JP-A-2000-43409, JP-A-2000-343811, JP-A-2002-120452 Cationic acrylic emulsion of latex (trade name “Aquabrid series ASi-781, ASi-784 manufactured by Daicel Chemical Industries, Ltd.” , ASi-578, ASi-903 ") and the like can also be mentioned as preferred, and polyallylamine and polyallylamine-modified products are particularly preferred.

  The polyallylamine-modified product is obtained by adding 2 to 50 mol% of acrylonitrile, chloromethylstyrene, TEMPO, epoxy hexane, sorbic acid or the like to polyallylamine, and preferably 5 to 5 of acrylonitrile, chloromethylstyrene, and TEMPO. It is a 10 mol% adduct, and 5 to 10 mol% TEMPO adduct of polyallylamine is particularly preferable from the viewpoint of exhibiting the effect of preventing ozone fading.

  The molecular weight of the mordant is preferably 2000 to 300,000 in terms of mass average molecular weight. When the molecular weight is within this range, water resistance and aging resistance can be further improved.

-Cationic polyurethane-
In the present invention, a cationic polyurethane can be contained in order to prevent the ink receiving layer from falling off the support and aging blur.

The content of the cationic urethane contained in the ink receiving layer of the present invention is preferably in the range of 0.3 to 5 g / m ² from the viewpoint of adhesion to a support and ink absorbability. 0.5 to 3.5 g / m ² is more preferable, and 0.8 to 2.5 g / m ² is particularly preferable. Prevention content of the cationic urethane and is ^{0.3g / m 2 ~5g / m 2} , an ink-receiving layer from the support by an impact at the time of processing cutting by time or guillotine cutter folding falling off Furthermore, it is possible to prevent aging blurring.

-Cationic polyurethane-
The ink jet recording medium of the present invention preferably contains cationic polyurethane as the mordant. By containing the cationic polyurethane in the ink receiving layer, it can act as a mordant, and the falling of the ink receiving layer from the support and aging blur can be improved.
In addition, when the cationic polyurethane is used together with the water-soluble cellulose and a water-soluble metal salt compound described later, the effect of suppressing the ink receiving layer from dropping from the support and aging blurring is particularly remarkable.

  The cationic polyurethane is not particularly limited, and various known ones can be used. Examples of the cationic polyurethane include cationic polyurethanes obtained by the following preparations (1) and (2). The cationic polyurethane is particularly preferably a composition in which cationic polyurethane is dispersed in water, that is, an aqueous dispersion.

According to the preparation (1) of the cationic polyurethane, the polyester polyol (B1) is used as the polyol for performing the urethane reaction with the polyisocyanate (A), and the chain extender (C) having a tertiary amino group is used. A cationic polyurethane is prepared by preparing a urethane prepolymer and neutralizing part of the tertiary amino group with an acid or quaternizing with a quaternizing agent so that the amine value is in the range of 1 to 40 (KOHmg / g). Can be obtained in the form of a composition.
According to Preparation (2), the polycarbonate polyol (B2), the chain extender (C) having a tertiary amino group, and the polyalkylene oxide (D) containing 50% by weight or more of an ethylene oxide chain, Polyurethane prepolymer is prepared using polyisocyanate (A), and the tertiary amino group introduced by the chain extender (C) is neutralized with an acid or quaternized with a quaternizing agent to form a cationic polyurethane. Can be obtained. Moreover, it can obtain as a water dispersion by obtaining with the form which disperse | distributed cationic polyurethane in water.

Hereinafter, the preparation (1) will be described.
As the polyisocyanate (A) in the present invention, conventionally used polyisocyanates such as aliphatic, alicyclic, aromatic and araliphatic can be used.
Specific examples of the aliphatic polyisocyanate include, for example, tetramethylene diisocyanate, dodecamethylene diisocyanate, 1,4-butane diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene. Examples thereof include diisocyanate, lysine diisocyanate, 2-methylpentane-1,5-diisocyanate, and 3-methylpentane-1,5-diisocyanate.

  Specific examples of the alicyclic polyisocyanate include, for example, isophorone diisocyanate, hydrogenated xylylene diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, methylcyclohexylene diisocyanate, 1,3-bis (isocyanate). And methyl) cyclohexane.

  Specific examples of the aromatic polyisocyanate include, for example, tolylene diisocyanate, 2,2′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate, 4,4′-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyl diisocyanate, 1,5-naphthylene diisocyanate, xylylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate and the like can be mentioned.

  Specific examples of the araliphatic polyisocyanate include dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, and α, α, α, α-tetramethylxylylene diisocyanate.

  These polyisocyanates can be used alone or in combination of two or more.

  As the polyester polyol (B1), those composed of various polycarboxylic acids and polyols can be used. Depending on the dicarboxylic acid composed of an aliphatic dibasic acid and an aromatic dibasic acid, and an aliphatic glycol, What is comprised is preferable at the point that adhesiveness becomes high. Examples of the aliphatic dibasic acid include malonic acid, succinic acid, tartaric acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, alkyl succinic acid, linolenic acid, maleic acid, fumaric acid , Mesaconic acid, citraconic acid, itaconic acid, glutaconic acid and the like, or reactive derivatives such as acid anhydrides, alkyl esters, acid halides, and the like. These aliphatic dicarboxylic acids can be used alone or in combination of two or more. Examples of the aromatic dibasic acid include phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, biphenyldicarboxylic acid, tetrahydro Examples thereof include phthalic acid and the like, or reactive derivatives thereof such as acid anhydrides, alkyl esters, and acid halides. These aromatic dicarboxylic acids can also be used alone or in combination of two or more.

  Examples of the aliphatic glycol include ethylene glycol, diethylene glycol, triethylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, and 1,6-hexanediol. , Propylene glycol and the like can be exemplified, and these can be used alone or in combination of two or more.

  The chain extender (C) having a tertiary amino group in the molecule is used for introducing the tertiary amino group into the urethane prepolymer. Examples of such chain extenders (C) include N-alkyldialkanolamines such as N-methyldiethanolamine and N-ethyldiethanolamine, N-alkyldiaminoalkylamines such as N-methyldiaminoethylamine and N-ethyldiaminoethylamine, A triethanolamine etc. can be mentioned. These chain extenders (C) having a tertiary amino group can be used alone or in combination of two or more.

  The addition amount of the chain extender (C) in the preparation (1) is 5 to 20% by mass with respect to the total of the polyisocyanate (A), the polyester polyol (B1), and the chain extender (C). preferable. When the added amount of the chain extender (C) is 5 to 20% by mass, the introduced tertiary amino group is sufficient, and adhesion, water resistance of the ink, and ease of preparation of the urethane prepolymer are improved. Etc.

  The content of free NCO at the end of the urethane prepolymer produced by the reaction of the polyisocyanate (A), the polyester polyol (B1), and the chain extender (C) having a tertiary amino group in the molecule is 1 It is preferable to be in the range of ˜5% by mass. When the content of the terminal free NCO is in the range of 1 to 5% by mass, the preparation of the urethane prepolymer is easy, and the cohesive force of the obtained water-based polyurethane resin does not become too high and the adhesiveness is excellent.

  In the above preparation (1), a cationic urethane prepolymer having a tertiary amino group introduced by the chain extender (C) and a part thereof neutralized with an acid or quaternized with a quaternizing agent is prepared. . When the tertiary amino group and a part thereof are neutralized with an acid, as the acid, formic acid, acetic acid, propionic acid, butyric acid, lactic acid, malic acid, malonic acid, adipic acid and other organic acids, and hydrochloric acid, phosphoric acid, Mention may be made of inorganic acids such as nitric acid. These acids can be used alone or in combination of two or more.

  In addition, when a tertiary amino group and a part thereof are quaternized with a quaternizing agent, quaternizing agents include alkyl halides such as benzyl chloride and methyl chloride, sulfate esters such as dimethyl sulfate and diethyl sulfate. Etc. These quaternizing agents can be used alone or in combination of two or more.

  In the present invention, as described above, the tertiary amino group and a part thereof are not completely neutralized or quaternized, and only a part of the tertiary amino group is neutralized or quaternized. The amount of the tertiary amino group left without being neutralized or quaternized is an amount such that the amine value of the cationic polyurethane is 1 to 40 (KOHmg / g). It can be adjusted by quaternization.

Hereinafter, the preparation (2) will be described.
The polyisocyanate (A) used in the preparation (2) is the same as the polyisocyanate (A) used in the preparation (1) as described.
Examples of the polycarbonate polyol (B2) used in the preparation (2) include a reaction of glycols such as 1,4-butanediol, 1,6-hexanediol, and diethylene glycol with diphenyl carbonate and phosgene. And the like. These aromatic dicarboxylic acids can be used alone or in combination of two or more.

  The addition amount of the polycarbonate polyol (B2) in the present invention is 40 to 80% by mass based on the total of the polyisocyanate (A), the polycarbonate polyol (B2), the chain extender (C), and the polyalkylene oxide (D2). A range is preferable. When the addition amount of the polycarbonate polyol (B2) is in the range of 40 to 80% by mass, the resulting urethane resin has high weather resistance and excellent adhesion to a plastic sheet. Furthermore, the resulting cationic polyurethane has sufficient cohesive strength and high water resistance.

  In this invention, it is preferable that the polyalkylene oxide (D2) containing 50 mass% or more of ethylene oxide chains is a constituent component of polyurethane. The polyalkylene oxide (D2) is used to increase the absorbability of the ink to be printed. Examples of such polyalkylene oxide (D2) include ethylene oxide, a copolymer of ethylene oxide and propylene oxide, and the like. These polyalkylene oxides (D2) can be used alone or in combination of two or more.

  The addition amount of the polyalkylene oxide (D2) is 3 to 10% by mass with respect to the total of the polyisocyanate (A), the polycarbonate polyol (B2), the chain extender (C), and the polyalkylene oxide (D2). It is preferable. When the addition amount of the polyalkylene oxide (D2) is 3 to 10% by mass, the ink absorbency and water resistance are good.

The chain extender (C) used in the preparation (2) is the same as in the preparation (1).
The addition amount of the chain extender (C) used in the preparation (2) is based on the total of the polyisocyanate (A), the polycarbonate polyol (B2), the chain extender (C), and the polyalkylene oxide (D). It is preferable that it is 5-15 mass%. When the added amount of the chain extender (C) is 5 to 15% by mass, the tertiary amino group to be introduced is sufficient and the adhesiveness is excellent.

  Acid and quaternizing agent when the tertiary amino group introduced by the chain extender (C) used in the preparation (2) and a part thereof are neutralized with an acid or quaternized with a quaternizing agent Is the same as in the case of the preparation (1).

  In the preparation of the above (1) and (2), the cationic urethane prepolymer obtained by neutralizing or quaternizing a tertiary amino group and a part thereof may be converted into a polyamine compound (D1) as needed when dispersed in water. ) May be used. Examples of polyamine compounds that can be used include, for example, amino groups such as ethylenediamine, propylenediamine, diethylenetriamine, hexylenediamine, triethylenetetramine, tetraethylenepentamine, isophoronediamine, piperazine, dihydrmethanediamine, hydrazine, adipic acid dihydrazide, and other hydrazides. And a compound having two or more.

  In the preparation of (1) and (2), a polyol having 3 or more hydroxyl groups may be further added. When a polyol having 3 or more hydroxyl groups is added, adhesion to a plastic sheet can be improved. However, it is necessary to use the obtained cationic polyurethane as long as the water dispersibility is not impaired. Examples of such polyols include sorbitol, 1,2,3,6-hexanetetraol, 1,4-sorbitan, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerin, trimethylol. Ethane, trimethylolpropane, pentaerythritol and the like can be mentioned, and these can be used alone or in combination of two or more.

  In the preparation of the above (1) and (2), the cationic urethane prepolymer obtained by neutralizing or quaternizing the tertiary amino group or part thereof as described above is then dispersed in water, The cationic polyurethane used in the invention and its dispersion are obtained.

  The cationic polyurethane can also be used in the form of the dispersant having the water-soluble resin. The content of the cationic polyurethane in the ink receiving layer is preferably 0.1 to 30% by mass, more preferably 3 to 15% by mass, and particularly preferably 5 to 10% by mass with respect to the fine particles. .

  Further, the cationic polyurethane may be in a form further containing an inorganic water absorbing material. Inorganic water-absorbing materials include light calcium carbonate, heavy calcium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium oxide, zinc oxide, zinc sulfate, zinc carbonate, satin white, aluminum silicate, diatomaceous earth, calcium silicate, none Examples thereof include regular silica, aluminum hydroxide, alumina, ritbon, etc. Amorphous silica is preferable from the viewpoint of printing speed and color developability.

  By using the cationic polyurethane, it can be applied to a sheet of soft polyvinyl chloride, semi-rigid polyvinyl chloride, rigid polyvinyl chloride, PET, polypropylene, polyethylene or the like.

  Specifically, the cationic polyurethane is a resin described in paragraphs [0006] to [0048] of JP-A No. 2002-307811 and paragraphs [0006] to [0053] of JP-A No. 2002-307812. Can be used.

(Metal salt compound)
The ink receiving layer of the ink jet recording medium of the present invention contains at least one of a zirconium compound and an aluminum compound as a metal salt compound. Hereinafter, when simply referred to as “zirconium compound” and “aluminum compound”, it means “zirconium salt compound” and “aluminum salt compound” unless otherwise specified.

  The ink jet recording medium of the present invention can improve the water resistance and aging resistance of a formed image by containing at least one of a zirconium compound and an aluminum compound as a metal salt compound in the ink receiving layer.

  As said metal salt compound, a water-soluble metal salt compound is preferable. Here, “water-soluble” means that 1% by mass or more dissolves in water at room temperature and normal pressure.

  The zirconium compound used in the present invention is not particularly limited, and various compounds can be used. For example, zirconium acetate, zirconium chloride, chlorinated zirconium oxide octahydrate, zirconium oxychloride, hydroxyzirconium chloride, zirconium nitrate, Examples thereof include basic zirconium carbonate, zirconium hydroxide, zirconium carbonate / ammonium carbonate, zirconium carbonate / potassium, zirconium sulfate, and a zirconium fluoride compound.

  Examples of the aluminum compound include aluminum sulfate, aluminum sulfite, aluminum thiosulfate, polyaluminum chloride, aluminum nitrate nonahydrate, aluminum chloride hexahydrate, and the like.

In particular, as the aluminum compound, for example, aluminum chloride which is an inorganic salt or a hydrate thereof, aluminum sulfate or a hydrate thereof, ammonium alum, and the like are known, and further, an inorganic aluminum-containing cationic polymer. Basic polyaluminum hydroxide compounds are also known.
Among these, as the aluminum compound, a basic polyaluminum hydroxide compound is particularly preferable.

The basic polyaluminum hydroxide compound has a main component represented by any one of the following general formulas (1) to (3). For example, [Al ₆ (OH) ₁₅ ] ³⁺ , [Al ₈ (OH) ₂₀ ] ⁴⁺ , [Al ₁₃ (OH) ₃₄ ] ⁵⁺ , [Al ₂₁ (OH) ₆₀ ] ³⁺ , etc. Aluminum oxide.

[Al ₂ (OH) _n Cl _6-n ] _m General formula (1)
[Al (OH) ₃ ] _n AlCl ₃ General formula (2)
Al _n (OH) _m Cl _(3n-m) 0 <m <3n General formula (3)

  These are commercially available as water treatment agents under the name of polyaluminum chloride (PAC) from Taki Chemical Co., Ltd., and under the name of polyaluminum hydroxide (Paho) from Asada Chemical Co., Ltd. ) Purakem WT from RIKEN GREEN is also commercially available for other purposes from other manufacturers, and various grades are readily available. In the present invention, these commercially available products can be used as they are, but when the pH is low, the pH can be appropriately adjusted and used.

  In the present invention, other metal salt compounds (preferably water-soluble metal salt compounds) can be used as long as the effects of the present invention are not impaired. Examples of the other metal salt compounds include water-soluble salts of metals selected from calcium, barium, manganese, copper, cobalt, nickel, iron, zinc, chromium, magnesium, tungsten, molybdenum, and titanium.

  Specifically, 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, second chloride Copper, ammonium chloride (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 Japanese products, zinc sulfate, chromium acetate, chromium sulfate, magnesium sulfate, magnesium chloride hexahydrate, magnesium citrate nonahydrate, phosphotungstic acid sodium Um, sodium tungsten citrate, 12 tungstophosphoric acid n-hydrate, dodecatungstosilicic acid 26-hydrate, molybdenum chloride, dodecamolybdophosphoric acid n-hydrate.

  In the present invention, the content of the metal salt compound (including at least one of an aluminum compound and a zirconium compound) in the ink receiving layer is preferably 0.1 to 10% by mass, and 1 to 5% by mass with respect to the fine particles. % Is more preferable. When the zirconium compound and the aluminum compound are used in combination, the mass ratio (zirconium compound / aluminum compound) is preferably 1/5 to 4/5, and more preferably 1/3 to 2/3. Moreover, when using together the said zirconium compound and aluminum compound, and said other metal salt compound, these mass ratios (total amount of a zirconium compound and an aluminum compound / other metal salt compounds) are 1 / 5-10 / 5 is preferable, and 1/2 to 1/1 is more preferable.

  Moreover, the said metal salt compound can be used individually, but 2 or more types can also be used together.

(Other ingredients)
The ink receiving layer in the invention is constituted by containing the following components as required. That is, the ink receiving layer in the present invention may contain anti-fading agents such as various ultraviolet absorbers, antioxidants, and singlet oxygen quenchers for the purpose of suppressing deterioration of the ink coloring material.
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 at least one of 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 contained in microcapsules. The addition amount of the anti-fading agent is preferably 0.01 to 10% by mass of the ink receiving layer coating solution.

  In the present invention, the ink receiving layer preferably contains a high boiling point organic solvent for curling prevention. The high-boiling organic solvent is preferably water-soluble, and examples of the water-soluble high-boiling organic solvent include ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, glycerin, diethylene glycol monobutyl ether (DEGMBE), Triethylene glycol monobutyl ether, glycerin monomethyl ether, 1,2,3-butanetriol, 1,2,4-butanetriol, 1,2,4-pentanetriol, 1,2,6-hexanetriol, thiodiglycol, Examples include alcohols such as triethanolamine and polyethylene glycol (weight average molecular weight of 400 or less). Diethylene glycol monobutyl ether (DEGMBE) is preferred.

The content of the high-boiling organic solvent in the ink-receiving layer coating solution is preferably 0.05 to 1% by mass, particularly preferably 0.1 to 0.6% by mass.
In addition, for the purpose of improving the dispersibility of the inorganic pigment fine particles, various inorganic salts, pH adjusting agents, and the like may contain acids and alkalis.
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.

(Support)
As the 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, an ink receiving layer can be provided on the label surface side using a read-only optical disc such as a CD-ROM or DVD-ROM, a write-once optical disc such as a CD-R or DVD-R, or a rewritable optical disc as a support. .

The material that can be used for the transparent support is preferably a material that is transparent and can withstand radiant heat when used in an OHP or a backlight display. Examples of 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.
Although there is no restriction | limiting in particular as thickness of the said transparent support body, 50-200 micrometers is preferable at the point of the 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 support body mentioned below is mentioned.

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

Although there is no restriction | limiting in particular also about the thickness of the said opaque support body, 50-300 micrometers is preferable at the point of the ease of handling.
The surface of the support is preferably 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 the pulp used for papermaking is preferably 200 to 500 ml as defined by CSF, and the fiber length after beating is a 24 mesh residual mass% and a 42 mesh residual as defined in JIS P-8207. 30 to 70% of the sum with the mass% of is preferable. The 4 mesh residue is preferably 20% by mass or less.

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

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

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

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

  Polyethylene-coated paper can be used as glossy paper, or 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 backcoat layer include an antifoaming agent, an antifoaming agent, a dye, a fluorescent brightening agent, a preservative, and a water-proofing agent.

(Preparation of inkjet recording medium)
The ink receiving layer of the ink jet recording medium of the present invention is, for example, coated on a support with a coating liquid (first coating liquid) containing at least the fine particles, the water-soluble resin, the mordant and the metal salt compound. The coating layer is formed, and (1) the coating solution (first coating solution) is coated to form the coating layer, or (2) the coating solution (first coating solution) is coated. At any time during the drying of the coating layer and before the coating layer exhibits reduced-rate drying, preferably the basic solution (second coating solution) having a pH of 8 or more is applied to the coating layer (first coating solution). It is preferably formed by a method in which the coating layer is crosslinked and cured (referred to as “Wet on Wet method” or “WOW method”). At this time, the cross-linking agent may be contained in either the coating solution (first coating solution) or the basic solution (second coating solution). When borax is used as the crosslinking agent, borax is preferably contained in the basic solution.

  As described above, the ink receiving layer obtained by applying a basic solution (second coating solution) to the first coating solution at the same time as (1) or during (2) drying is crosslinked and cured. In addition to having advantages such as ink absorbability and prevention of film cracking, it is particularly preferable for improving the appearance of repelling failure and the like.

  The mordant is preferably present such that the thickness of the portion where the mordant is present from the surface of the ink receiving layer is 10 to 60% with respect to the total thickness of the ink receiving layer. For example, (1) a method of forming a coating layer containing fine particles, a water-soluble resin and a crosslinking agent, and applying a mordant-containing solution thereon, (2) a coating solution containing the fine particles and a water-soluble resin, and a mordant containing It can be formed by any method such as a method of applying a solution in multiple layers. The mordant-containing solution may contain fine particles, a water-soluble resin, a crosslinking agent, and the like. When configured as described above, since a large amount of mordant is present in a required portion of the ink receiving layer, the ink color material of the ink jet is sufficiently mordanted, and the color density, aging blur, gloss of the print area, characters and images after printing are printed. It is preferable because water resistance and ozone resistance are further improved. Part of the mordant may be contained in the layer initially provided on the support, and in that case, the mordant to be applied later may be the same or different.

In the present invention, the coating liquid containing the inorganic pigment fine particles, the water-soluble resin, and the boron compound (crosslinking agent) as the first coating liquid can be prepared, for example, as follows.
That is, silica fine particles having an average primary particle size of 20 nm or less are added to water (for example, 10 to 20% by mass), and a high-speed rotating wet colloid mill (for example, “Clairemix” manufactured by M Technique Co., Ltd.) is used. For example, after being dispersed for 20 minutes (preferably 10 to 30 minutes) under the condition of high-speed rotation of 10000 rpm (preferably 5000 to 20000 rpm), a boron compound (for example, 0.5 to 20 of silica) (Mass%) and dispersion under the same conditions as above, and an aqueous polyvinyl alcohol solution (for example, PVA having a mass of about 1/3 of silica), and further dispersion under the same rotation conditions as above. Can be prepared. The obtained coating solution is a uniform sol, and this is applied to a support by the following coating method to form an ink-receiving layer having a porous structure having a three-dimensional network structure.
If necessary, a pH adjuster, a dispersant, a surfactant, an antifoaming agent, an antistatic agent and the like can be further added to the first coating liquid.

  As the dispersing machine used for the above dispersion, various conventionally known dispersing machines such as a high-speed rotary dispersing machine, a medium stirring type dispersing machine (ball mill, sand mill, etc.), an ultrasonic dispersing machine, a colloid mill dispersing machine, and a high-pressure dispersing machine are used. However, in order to efficiently disperse the generated fine particles, a medium stirring type disperser, a colloid mill disperser or a high pressure disperser is preferable.

  Moreover, water, an organic solvent, or these mixed solvents can be used as a solvent used for preparation of each coating liquid. Examples of organic solvents that can be used in the coating solution include alcohols such as methanol, ethanol, n-propanol, i-propanol, and methoxypropanol, ketones such as acetone and methyl ethyl ketone, tetrahydrofuran, acetonitrile, ethyl acetate, and toluene. Can be mentioned.

Moreover, the 2nd coating liquid (basic solution) containing surfactant can be prepared as follows, for example. That is, a mordant (for example, 0.1 to 5.0% by mass) and a surfactant (for example, a total amount of 0.01 to 1.0% by mass) in ion-exchanged water and a crosslinking agent (0 to 0 as necessary). 5.0% by mass) and sufficiently stirred. The pH of the second coating liquid is preferably 8.0 or more, and pH adjustment is carried out using ammonia water, sodium hydroxide, calcium hydroxide, amino group-containing compounds (ethylamine, ethanolamine, diethanolamine, polyallylamine, etc.) and the like. .0 or more can be appropriately performed.
Furthermore, an acid can be added to the basic solution for pH adjustment. As the acid, either an organic acid or an inorganic acid may be used. For example, p-toluenesulfonic acid, formic acid, acetic acid, succinic acid, etc. Examples of the acid include citric acid, phthalic acid, and ammonium chloride, and paratoluenesulfonic acid and ammonium chloride are preferable.

  Application of the first coating liquid (ink receiving layer coating liquid) is, for example, a known coating such as an extrusion die coater, air doctor coater, bread coater, rod coater, knife coater, squeeze coater, reverse roll coater, bar coater, etc. It can be done by the method.

  The second coating liquid (basic solution) is applied to the coating layer simultaneously with or after the application of the first coating liquid (ink-receiving layer coating liquid). It may be applied before the coating layer exhibits reduced rate drying. That is, after the application liquid for the ink receiving layer is applied, it is preferably manufactured by introducing a basic solution while the applied layer exhibits constant rate drying. The second coating liquid may contain a mordant.

  Here, “before the coating layer comes to show reduced drying” usually refers to a process for several minutes immediately after the coating of the coating liquid for the ink-receiving layer. This shows a phenomenon of “constant rate drying” in which the content of the solvent (dispersion medium) of the ink decreases in proportion to time. The time indicating “constant rate drying” is described in, for example, “Chemical Engineering Handbook” (pages 707 to 712, published by Maruzen Co., Ltd., October 25, 1980).

  As described above, after the application of the first coating liquid, the coating layer is dried until the coating layer exhibits reduced-rate drying. This drying is generally performed at a temperature of 50 to 180 ° C. for 0.5 to 10 minutes (preferably 0.5 ~ 5 minutes). The drying time naturally varies depending on the coating amount, but the above range is usually appropriate.

  As a method of applying the second coating liquid before the reduced rate of drying is exhibited, (1) a method of further applying the second coating liquid on the coating layer, and (2) a method of spraying by a method such as spraying (3) A method of immersing the support on which the coating layer is formed in the second coating liquid.

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

The coating amount of the second coating solution, 5 to 50 g / m ² is generally, 10 to 30 g / m ² is preferred.

  After the application of the second coating liquid, it is generally heated at a temperature of 40 to 180 ° C. for 0.5 to 30 minutes, and dried and cured. Especially, it is preferable to heat at a temperature of 40 to 150 ° C. for 1 to 20 minutes. For example, when the cross-linking agent contained in the first coating liquid is borax or boric acid, heating at a temperature of 60 to 100 ° C. is preferably performed for 5 to 20 minutes.

  Further, when the basic solution (second coating solution) is applied simultaneously with the application of the ink receiving layer coating solution (first coating solution), the first coating solution supports the first coating solution and the second coating solution. The ink receiving layer can be formed by simultaneously applying (multilayer coating) on the support so as to come into contact with the body, followed by drying and curing.

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

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

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

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

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

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

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

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

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the examples, “parts” and “%” all represent “parts by mass” and “% by mass”.

[Example 1]
(Production of support)
Wood pulp composed of 100 parts of LBKP is beaten to 300 ml Canadian freeness with a double disc refiner, 0.5 parts of epoxidized behenamide, 1.0 part of anionic polyacrylamide, 0.1 part of polyamide polyamine epichlorohydrin, 0.5 part of cationic polyacrylamide All parts were added at an absolutely dry mass ratio with respect to the pulp, and weighed with a long net paper machine to produce a base paper of 170 g / m ² .

In order to adjust the surface size of the base paper, 0.04% of a fluorescent whitening agent (“Whiteex BB” manufactured by Sumitomo Chemical Co., Ltd.) was added to a 4% aqueous solution of polyvinyl alcohol, and this was converted to 0 in terms of absolute dry weight. The base paper was impregnated to a density of 0.5 g / m ² , dried, and then subjected to a calendering process to obtain a base paper adjusted to a density of 1.05.

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 19 μm using a melt extruder to form a resin layer composed of a mat surface. (Hereinafter, this resin layer surface is referred to as “back surface”). The back side resin layer is further subjected to a corona discharge treatment, and thereafter, as an antistatic agent, aluminum oxide (“Alumina Sol 100” manufactured by Nissan Chemical Industries, Ltd.) and silicon dioxide (“Snow manufactured by Nissan Chemical Industries, Ltd.”) are used. Tex O ") the mass ratio of 1: a dispersion dispersed in water at 2, dry weight was coated to a 0.2 g / m ^2.

  Further, after the corona discharge treatment is performed on the felt surface (surface) side where the resin layer is not provided, anatase type titanium dioxide 10%, a trace amount of ultramarine blue, and a fluorescent whitening agent 0.01% (vs. polyethylene) Low-density polyethylene containing MFR (melt flow rate) 3.8 is melt-extruded to a thickness of 29 μm using a melt extruder, and a high-gloss thermoplastic resin layer is formed on the surface side of the base paper. (Hereinafter, this highly glossy surface is referred to as “front side”), and used as a support for this example.

(Preparation of coating solution for ink receiving layer)
(1) Inorganic fine particles, (2) Dispersant, and (3) Ion-exchanged water in the following composition are mixed, and using a high-speed rotating colloid mill (“CLEARMIX” manufactured by M Technique Co., Ltd.) After being dispersed for 20 minutes at a rotational speed of 10,000 rpm, the following (4) cross-linking agent, (5) water-soluble resin (polyvinyl alcohol), (6) water-soluble resin (water-soluble cellulose), (7) diethylene glycol monobutyl ether (8)) A water-soluble metal salt compound, (9) a cationic polyurethane, and (10) a surfactant were added, and further dispersed under the same conditions as described above to prepare an intended ink-receiving layer coating solution.

<Composition of coating liquid for ink receiving layer>
(1) Inorganic pigment fine particles 100 parts (Brand name: Leolosil QS-30, manufactured by Tokuyama Corporation, average primary particle size: 7 nm)
(2) Dispersant 20.0 parts (Brand name: Chemistat 7005, 40% aqueous solution, manufactured by Sanyo Chemical Industries, Ltd.)
(3) Ion-exchanged water 547.9 parts (4) Crosslinker 77.4 parts (Boric acid, 5.3% aqueous solution)
(5) Water-soluble resin (polyvinyl alcohol) 317.2 parts (trade name: PVA124, 7% aqueous solution, manufactured by Kuraray Co., Ltd.)
(6) 12.5 parts of water-soluble resin (water-soluble cellulose) (trade name: HPC-SSL, 10% aqueous solution, manufactured by Nippon Soda Co., Ltd., coating amount: 0.2 g / m ² )
(7) Diethylene glycol monobutyl ether 10.9 parts (vapor pressure 3 Pa, coating amount: 1.74 g / m ² )
(8) 6.3 parts of water-soluble metal salt compound (trade name: Zircosol ZA-30, 30% aqueous solution, manufactured by Daiichi Rare Element Chemical Industries, Ltd.)
(9) 24.9 parts of cationic polyurethane (trade name: Superflex 600-B, 25% dispersion, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., coating amount: 1.0 g / m ² )
(10) Surfactant (polyoxyethylene oleyl ether) 9.3 parts (trade name: Emulgen 109P, 10% aqueous solution, manufactured by Kao Corporation)
(11) Surfactant (Fluorine Surfactant) 6.0 parts (Product name: Megafac F-1405, 10% aqueous solution, manufactured by Dainippon Ink & Chemicals, Inc.)

(Preparation of inkjet recording sheet)
After the corona discharge treatment was applied to the front surface of the support, the ink receiving layer coating solution obtained above was applied to the front surface of the support at an application amount of 170 ml / m ² using an extrusion die coater. It was applied (application process), and dried with a hot air dryer at a temperature of 40 ° C. (wind speed 5 m / sec) until the solid content concentration of the application layer reached 18%. During this time, the coating layer exhibited a constant rate of drying. Immediately after that, it is immersed in a basic solution (pH = 9.6) having the following composition, 10 g / m ² is adhered onto the coating layer (solution application step), and further dried at a temperature of 80 ° C. for 10 minutes. (Drying process). As a result, an inkjet recording sheet of the present invention provided with an ink receiving layer having a dry film thickness of 35 μm was obtained.

<Composition of basic solution>
-15 parts of crosslinking agent (borax (100%), coating amount: 0.15 g / m ² )
・ Mordant 100.0 parts (trade name: PAA-03, 20% aqueous solution, manufactured by Nitto Boseki Co., Ltd.)
・ Ion-exchanged water 776 parts ・ Surface pH adjuster (ammonium chloride, 100%) 1.0 part ・ Surface pH adjuster (p-toluenesulfonic acid, 100%) 6.0 parts ・ Surfactant 100.0 parts ( Product name: Emulgen 109P, 2% aqueous solution, manufactured by Kao Corporation)
・ Surfactant (Fluorosurfactant) 2.0 parts (Product name: Megafac F-1405, 10% aqueous solution, manufactured by Dainippon Ink & Chemicals, Inc.)

[Example 2]
In Example 1, the amount of ion-exchanged water added in the composition of the ink-receiving layer coating solution was changed to 533.8 parts, and an aluminum salt compound (trade name: Alphain 83, 23% aqueous solution, Daimei Chemical Industries, Ltd.) A coating solution for an ink-receiving layer was prepared in the same manner as in Example 1 except that 14.1 parts of (made by Co., Ltd.) was added, and an inkjet recording sheet of the present invention was produced.

[Example 3]
In Example 1, the addition amount of the crosslinking agent (borax) in the composition of the basic solution was changed to 8 parts (coating amount: 0.08 g / m ² ), and ion-exchanged water in the composition of the basic solution was changed. An ink receiving layer coating solution was prepared in the same manner as in Example 1 except that the addition amount was changed to 783 parts, and an ink jet recording sheet of the present invention was produced.

[Example 4]
In Example 1, the addition amount of the crosslinking agent (borax) in the composition of the basic solution was changed to 28 parts (coating amount: 0.28 g / m ² ), and ion exchange in the composition of the basic solution was performed. An ink receiving layer coating solution was prepared in the same manner as in Example 1 except that the amount of water added was changed to 763 parts, and an inkjet recording sheet of the present invention was produced.

[Comparative Example 1]
In Example 1, the crosslinking agent (borax) in the composition of the basic solution was changed to 6.5 parts of boric acid (coating amount: 0.065 g / m ² ). An ink receiving layer coating solution was prepared in the same manner as in Example 1 except that the amount of ion-exchanged water added was changed to 784.5 parts, and a comparative inkjet recording sheet was prepared.

[Comparative Example 2]
Ink was prepared in the same manner as in Example 1 except that the amount of ion-exchanged water added in the composition of the coating liquid for ink-receiving layer was changed to 554.2 parts and no water-soluble metal salt compound was used. A receiving layer coating solution was prepared, and a comparative inkjet recording sheet was prepared.

[Comparative Example 3]
In Example 1, the amount of ion-exchanged water added in the composition of the coating solution for the ink receiving layer was changed to 554.2 parts, no water-soluble metal salt compound was used, and cross-linking in the composition of the basic solution was performed. Example 1 except that the addition amount of the agent (borax) was changed to 5 parts (coating amount: 0.05 g / m ² ) and the addition amount of ion-exchanged water in the composition of the basic solution was changed to 786 parts. In the same manner, an ink-receiving layer coating solution was prepared, and a comparative inkjet recording sheet was prepared.

"Evaluation test"
<Preparation of sample>
Samples corresponding to the respective examples and comparative examples were prepared. The sample was prepared by stirring the sample obtained by removing the inorganic pigment fine particles from the composition of the ink receiving layer coating solution used in each Example and Comparative Example, and preparing a sample coating solution corresponding to each Example and Comparative Example. .

  Each sample coating solution obtained from the above was coated on the support using a # 60 bar so that the dry film thickness was 5 μm. After coating, the coated film was dried in an oven at 70 ° C. for 4 minutes, and then each sample was immersed in a basic solution containing a boron compound in each example for 20 seconds. Next, excess basic solution adhering to the surface of the sample was scraped off with a # 5 bar and dried in an oven until the resin coating was completely dried, thereby obtaining samples corresponding to each of the examples and comparative examples.

  The following evaluation tests were conducted on the ink jet recording sheets of Examples and Comparative Examples obtained above. The results are shown in Table 1 below.

(1) Dissolution time A mixed solution having the following composition is dropped onto the obtained sample, and the tip of the resin film formed on the sample using a swelling meter has a stylus made of quartz glass with a hemispherical tip made of quartz glass. The swelling rate of the resin film in each sample was measured using a swelling meter.
[Composition of the mixed solution]
・ Water 67.5 parts ・ Glycerin 8 parts ・ Triethylene glycol 6.5 parts ・ 2-Pyrrolidone 3 parts ・ Triethylene glycol monobutyl ether 8.5 parts ・ Triethanolamine 6.5 parts

The dissolution time was measured by dropping 0.2 g of a mixed solution having the following composition into the sample. Dissolution time is measured from when the mixed solution is dropped (when the dropped mixed solution comes into contact with the resin coating surface), and a stylus is brought into contact with the resin coating surface with a load of 2.0 g every 4 seconds. And the time until the swelling rate becomes minus 50% was measured.
The results are shown in Table 1.

(2) Bronze gloss evaluation After storage for 24 hours under conditions of room temperature of 35 ° C. and relative humidity of 80%, an inkjet printer (trade name: PM900C, manufactured by Seiko Epson Corporation) is used for inkjet recording under the same conditions. A blue solid image was printed on the sheet. After printing, the printing screen of the inkjet recording sheet was visually observed and evaluated according to the following criteria.
[Standard]
○: No metallic luster was observed on the stamp screen.
Δ: Although a slight metallic luster was recognized on the marking screen, it was in a range that had no practical problem.
X: A metallic luster was remarkably recognized on the marking screen.

(2) Time-lapse blurring Using an inkjet printer (trade name: BJF-900, manufactured by Canon Inc.), magenta and yellow inks are adjacent to each inkjet recording sheet to form a grid-like linear pattern (width 0). .28 mm). The print sample was inserted into a transparent polypropylene file and stored in an environment of a temperature of 35 ° C. and a relative humidity of 80% for 3 days. Thereafter, the width of the linear magenta was measured, and the increase rate (%) of the magenta line width with respect to the width immediately after printing was calculated as an evaluation index for aging blur.
Incidentally, when the aging blur is 145% or less, there is no practical problem.
The results are shown in Table 1.

As shown in Table 1, it can be seen that the ink jet recording sheets of the examples have a dissolution time of 100 seconds or more, and the occurrence of bronze gloss and blurring with time is suppressed.
In contrast, Comparative Examples 1 and 4 having a dissolution time of 100 seconds or less could not sufficiently suppress the occurrence of bronze gloss. Further, Comparative Examples 3 and 4 in which no metal salt compound was used could not sufficiently suppress the occurrence of aging blur.

It is the schematic for demonstrating the swelling degree meter in this invention. It is a graph which shows the relationship between melt | dissolution time and swelling rate.

Explanation of symbols

10 swelling clock 12 stylus 14 thickness displacement measuring instrument 16 CPU
18 Sample 20 Resin coating 22 Support 24 Mixed solution

Claims (6)

An ink jet recording medium having an ink receiving layer containing fine particles, a water-soluble resin, a crosslinking agent, a mordant, and a metal salt compound on a support,
When the metal salt compound contains at least one of a zirconium compound and an aluminum compound, and a resin film having a thickness of 5 μm is formed from the components included in the ink receiving layer excluding the fine particles, 67.5% by mass of water is formed. A resin mixture containing 8% by mass of glycerin, 6.5% by mass of triethylene glycol, 3% by mass of 2-pyrrolidone, 8.5% by mass of triethylene glycol monobutyl ether and 6.5% by mass of triethanolamine. An ink jet recording medium characterized in that the time from when 0.2 g is dropped on the film until the swelling ratio measured by a swelling meter becomes minus 50% is 100 seconds or more.   The ink receiving layer is coated with a coating liquid containing the fine particles, the water-soluble resin, the mordant, and the metal salt compound on the support to form a coating layer, and the coating liquid is coated. At the same time as forming the coating layer, or while the coating layer formed by coating the coating solution is being dried and before the coating solution exhibits reduced-rate drying, the basic solution is added to the coating layer. The inkjet recording medium according to claim 1, wherein the inkjet recording medium is formed by being applied to the coating liquid and the crosslinking agent is contained in at least one of the coating solution and the basic solution.   The inkjet recording medium according to claim 1, wherein the crosslinking agent contains a boron compound.   The inkjet recording medium according to claim 1, wherein the crosslinking agent is contained in the basic solution.   The ink jet recording medium according to claim 2, wherein the basic solution contains borax as the cross-linking agent. Wherein wherein the crosslinking agent is at least borax, inkjet according to claim 1, the coating amount of the borax in the ink receiving layer is characterized in that it is a 0.07~0.3g / m ² recoding media.

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