JP2010076221A - Inkjet recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink-jet recording medium superior in cuttability during its cutting. <P>SOLUTION: The ink-jet recording medium having inorganic particles and an ink receiving layer including water-soluble resin provided on at least one side of its support includes an aqueous lubricant having an average molecular weight of ≥350. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an inkjet recording medium.

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

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

In addition to the above requirements, there is a demand for development of a system for printing photographs at high speed using an inkjet system, such as a minilab. In order to perform high-speed printing, a roll conveyance system is preferable, but it is necessary to provide a mechanism for cutting sheets in an ink jet printer.
However, since the ink-jet image receiving layer uses a material having an abrasive ability such as silica, the cutter blade is heavily worn, and the periphery of the edge is liable to be cracked or cracked during borderless printing. There is a problem that requires maintenance.

On the other hand, various ink jet recording media are disclosed in relation to the above.
For example, an ink jet recording medium is disclosed in which a specific polyglycerin derivative is added to the ink absorbing layer to reduce ink back-through and ink bleeding (see, for example, Patent Document 1).
Further, a coated paper obtained by coating the surface with a paper sizing agent containing a diglycerin derivative having a specific structure capable of expressing a high printing density and good feathering resistance is disclosed (for example, , See Patent Document 2).
JP 2004-268334 A JP-A-2005-9043

  The present invention has been made in view of the above, and an object of the present invention is to provide an ink jet recording medium excellent in cutter suitability when cutting an ink jet recording medium, and to achieve the object.

<1>
An ink jet recording medium comprising an aqueous lubricant having an ink receiving layer containing inorganic fine particles and a water-soluble resin on at least one surface of a support and having an average molecular weight of 350 or more.
<2>
The inkjet recording medium according to <1>, wherein the aqueous lubricant is a diglycerin derivative.
<3>
The inkjet recording medium according to <1> or <2>, wherein the content of the aqueous lubricant is 5 to 20% by mass with respect to the inorganic fine particles.
<4>
The inkjet recording medium according to any one of <1> to <3>, wherein the inorganic fine particles are vapor-phase-process silica.
<5>
The inkjet recording medium according to any one of <1> to <4>, wherein the aqueous lubricant is contained in an intermediate layer.
<6>
The inkjet recording medium according to any one of <1> to <5>, wherein the ink receiving layer is provided on both surfaces of the support.

  ADVANTAGE OF THE INVENTION According to this invention, the inkjet recording medium excellent in the cutter suitability at the time of cutting an inkjet recording medium can be provided.

≪Inkjet recording medium≫
The ink jet recording medium of the present invention is characterized in that it has an ink receiving layer containing inorganic fine particles and a water-soluble resin on at least one surface of a support and contains an aqueous lubricant having an average molecular weight of 350 or more.
The ink jet recording medium of the present invention has excellent cutter suitability when the ink jet recording medium is cut by adopting the above configuration.
The water-based lubricant needs to have a molecular weight of 350 or more in order to exhibit hydrophilic / hydrophobic characteristics.
Here, “excellent in cutter suitability” means that when cut with a cutter, the ink receiving layer is cracked in the vicinity of the cut surface, and the image is disturbed due to the crack. This is a state in which the conspicuous appearance is suppressed.
The above problem of cracks and the problem of image distortion caused by the cracks become worse with the number of cut sheets. Therefore, the more the number of sheets that can be cut before these problems occur, the better the cutter suitability.
Hereinafter, the ink jet recording medium of the present invention will be described in detail.

If the ink jet recording medium of the present invention has an aqueous lubricant, it may be an ink jet recording medium (hereinafter also referred to as a single-sided product) in which the ink receiving layer is provided only on one side of the support, or ink on both sides. An ink jet recording medium provided with a receiving layer (hereinafter also referred to as a double-sided product) may be used. .
Furthermore, the single-sided product may have a configuration in which the ink receiving layer has two or more layers, or may have a configuration in which an intermediate layer is provided between the support and the ink receiving layer. Further, a layer structure in which an additive layer, a barrier layer, or the like is provided between the support and the ink receiving layer may be employed.
On the other hand, in the case of a double-sided product, an embodiment in which a layer in the single-sided product is formed on both sides of a support. That is, the structure may be such that there are two or more ink receiving layers on both sides of the support, or an intermediate layer may be provided between the support and the ink receiving layer. Further, a layer structure in which an additive layer, a barrier layer, or the like is provided between the support and the ink receiving layer may be employed.
Among the single-sided and double-sided products of the inkjet recording medium of the present invention, when the inkjet recording medium is a double-sided product, it is preferable in that the effect of the cutter suitability (property of being easily cut with a cutter) of the present invention becomes remarkable.
The double-sided product of the inkjet recording medium is preferably used for applications such as a photo book. The double-sided inkjet recording medium is excellent in terms of resource saving because it is not necessary to bond two recording media.

As described above, the inkjet recording medium of the present invention may have an ink receiving layer containing inorganic fine particles and a water-soluble resin on at least one surface of a support and may contain a specific aqueous lubricant. The water-based lubricant may be contained in the ink receiving layer or in any other layer such as an intermediate layer.
The aspect of the layer structure of the inkjet recording medium in the present invention is as follows, and the aqueous lubricant is preferably present in an adjacent layer adjacent to the support. In the one-sided product of (1), ( 1-1) Ink receiving layer, (1-2) Intermediate layer, (1-3) Ink receiving layer (kaolin layer), (1-4) Ink receiving layer (lower layer), (1-5) Addition layer, etc. Yes, (2) In a double-sided product, it is a layer corresponding to a single-sided product.
By having it in a layer adjacent to the support, the cutter suitability effect is great and the adverse effects can be minimized.

(1) Single-sided product (1-1) Support / ink receiving layer (1-2) Support / intermediate layer / ink receiving layer (1-3) Support / ink receiving layer (kaolin layer) / ink receiving layer ( 1-4) Support / ink receiving layer (lower layer) / ink receiving layer (upper layer)
(1-5) Support / addition layer / barrier layer / ink receiving layer (2) Double-sided product (2-1) Ink receiving layer / support / ink receiving layer (2-2) Ink receiving layer / intermediate layer / support Body / intermediate layer / ink receiving layer (2-3) ink receiving layer / ink receiving layer (kaolin layer) / support / ink receiving layer (kaolin layer) / ink receiving layer (2-4) ink receiving layer (upper layer) / Ink receiving layer (lower layer) / Support / Ink receiving layer (lower layer) / Ink receiving layer (upper layer)
(2-5) Ink receiving layer / barrier layer / added layer / support / added layer / barrier layer / ink receiving layer and the like are exemplified, but the present invention is not limited thereto.

<Water-based lubricant>
The aqueous lubricant having an average molecular weight of 350 or more in the present invention is an aqueous lubricant having a solubility in water at 20 ° C. of 5% or more, and is in the form of liquid, paste or wax (in a state where water is evaporated). In addition, the compatibility with PVA is low and phase separation occurs.
When cutting an ink jet recording medium having an ink receiving layer, cracks in the ink receiving layer near the cut surface and image disturbance due to the cracks (this image disturbance is particularly noticeable during borderless printing) In order to suppress this, the sliding between the cutter and the ink jet recording medium is promoted and used for reducing the friction.

The water-based lubricant in the present invention needs to have an average molecular weight of 350 or more, but from the viewpoint of lubrication effect and liquid preparation suitability, it is preferably 600 or more, more preferably 600 or more and 2000 or less, and still more preferably 800 or more and more. 1600 or less.
When the average molecular weight is 600 or more, the lubricating effect tends to be high, and when it is 2000 or less, the liquid preparation suitability tends to be improved.

Among these, examples of the aqueous lubricant include nonionic surfactants having a hydrophilic part and a hydrophobic part.
Furthermore, a highly hydrophilic polyhydric alcohol and a relatively hydrophobic ether compound of PPG are preferred, and a diglycerin derivative is more preferred.

  Examples of the diglycerin derivative include one or more selected from the following general formulas (1) and (2).

In the general formula (1), m, n, o, and p each independently represent an integer of 0 or more, and m + n + o + p is preferably 6 to 40, more preferably 6, 13, 20, 30, 40, Preferably, it is 13, 20, 30.
The general formula (1) may be a synthetic product or a commercially available product. The synthetic product can be obtained by addition polymerization of ethylene oxide to diglycerin. Examples of commercially available products include SC-E series (SC-E450 (POE (6) diglyceryl ether), SC-E750 (POE (13) diglyceryl ether), SC-E) manufactured by Sakamoto Pharmaceutical Co., Ltd. E1000 (POE (20) diglyceryl ether), SC-E1500 (POE (30) diglyceryl ether), SC-E2000 (POE (40) diglyceryl ether), etc.).

In the general formula (2), m, n, o, and p each independently represent an integer of 0 or more, and m + n + o + p is preferably 4 to 24, more preferably 4, 9, 14, 18, 24, Preferably, 9, 14, 18.
The general formula (2) may be a synthetic product or a commercially available product. A synthetic product can be obtained by addition polymerization of propylene oxide to diglycerin. Examples of commercially available products include SC-P series (SC-P400 (POP (4) diglyceryl ether), SC-P750 (POP (9) diglyceryl ether), SC-P, manufactured by Sakamoto Pharmaceutical Co., Ltd.). P1000 (POP (14) diglyceryl ether), SC-P1200 (POP (18) diglyceryl ether), SC-P1600 (POP (24) diglyceryl ether), etc.).

  In the present invention, the content of the aqueous lubricant is preferably an ink jet recording medium containing 50% by mass or less with respect to inorganic fine particles described later, more preferably 5 to 20% by mass, and still more preferably. It is 8-16 mass%.

<Ink receiving layer>
The ink receiving layer in the invention may be provided on the support directly or via another layer, and the layer structure of the ink receiving layer may be a single layer structure or a multilayer structure.
Hereinafter, each component contained in the ink receiving layer will be described.

(Inorganic fine particles)
The ink receiving layer according to the present invention (the above aspects (1-1) to (2-5)) contains inorganic fine particles.
Examples of the inorganic fine particles include silica fine particles, colloidal silica, titanium dioxide, barium sulfate, calcium silicate, zeolite, kaolinite, halloysite, mica, talc, calcium carbonate, magnesium carbonate, calcium sulfate, boehmite, pseudoboehmite and the like. be able to. Among these, silica fine particles are preferable.

The silica (silica fine particles) is generally 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. The silica fine particles obtained by the wet method are also referred to as “wet method silica” in the present invention.
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. A method of obtaining anhydrous silica by the (arc method) is the mainstream. In the present invention, “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 aggregate (aggregate) easily, In the case of the method silica, the density of silanol groups on the surface of the fine particles is as small as ² to 3 / nm ² , so that it becomes sparse soft agglomeration (flocculate), and as a result, it is estimated that the structure has a high porosity. The

As the silica contained in the ink receiving layer, vapor-phase method silica having a density of silanol groups on the surface of 2 to 3 / nm ² is particularly preferable.

The average particle diameter of the primary particles of silica contained in the ink receiving layer is not particularly limited, but is preferably 10 nm or less from the viewpoint of further improving the ink absorbability.
The specific surface area by the BET method of the silica contained in the ink receiving layer is preferably at least ^{200m 2 / g, 250m 2 /} g or more and more preferably, 380 m ² / g or more is particularly preferable. When the specific surface area of the vapor-phase process silica contained in the ink receiving layer is 200 or more m ² / g, the ink receiving layer has high transparency, and the printing density can be kept high.

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

In the ink receiving layer, the silica and other pigments other than silica may be used in combination as a pigment component.
Examples of the other pigments include colloidal silica, titanium dioxide, barium sulfate, calcium silicate, zeolite, halloysite, mica, talc, calcium carbonate, magnesium carbonate, calcium sulfate, boehmite, and pseudoboehmite.

As a mass ratio of the silica with respect to all the pigment components in an ink receiving layer, 60-100 mass% is preferable and 80-100 mass% is more preferable from a viewpoint which improves ink absorptivity more.
Moreover, as a mass ratio of the silica with respect to the total solid content in an ink receiving layer, 40-90 mass% is preferable from a viewpoint of improving ink absorptivity more, and 50-80 mass% is more preferable.

~ Kaolin ~
When the ink jet recording medium of the present invention is the above aspect (1-3) or (2-3), the ink receiving layer (first ink receiving layer) having two ink receiving layers and closer to the support. Or particularly a kaolin layer) contains at least one kaolin as the inorganic fine particles.
The kaolin is used as a pigment in the first ink receiving layer, thereby suppressing the glossiness of the entire ink receiving layer. Furthermore, cutter suitability and handleability are improved.
The kaolin is not particularly limited, and natural kaolin clay (hereinafter, also simply referred to as “kaolin clay”), calcined kaolin, derami kaolin, or the like treated with kaolin clay can be used.

  The calcined kaolin is anhydrous aluminum silicate which is made amorphous by heating natural kaolin clay at a high temperature in a calcining furnace to remove crystal water. Examples of calcined kaolin include Alphatex and Opatitex manufactured by Imeris Minerals Japan, Kaocal manufactured by Shiraishi Calcium Co., Ltd., Ancilex 93 manufactured by Engelhard, and Takehara Chemical Industry Co., Ltd. Glomax LL, etc. can be mentioned.

The delaminated kaolin is obtained by applying mechanical force to kaolin clay (kaolinite) produced in nature to perform delamination pulverization, and has a flat plate shape. Kaolinite, a dioctahedral 1: 1 layered silicate, 1: The chemical composition of the first layer _{ideally, Al 2 Si 2 O 5 ·} (OH) is a _4, octahedral As the cation, Al is often substituted to contain some Fe ³⁺ . Therefore, kaolinite generally has a plate shape, but when a physical force is applied from the outside, delamination occurs, and a flattened kaolinite is obtained. Since this pulverization method is intended for delamination, it is generally called delamination pulverization, and kaolinite obtained by this operation is called delaminated kaolin or delamination clay, delaminated clay, delamination clay, or the like. The delaminated kaolin in the present invention also includes engineered delaminated kaolin having a particle diameter in a specific range.
Further, the aspect ratio of kaolin is generally about 15 to 20, but there are some which are called engineered delaminated kaolin, especially those which are refined and have a uniform particle diameter exceeding 50.

  Examples of deramikaolin include Astra Plates manufactured by Imeris Minerals Japan Co., Ltd., Kao White S, Kao White, Kao White C, etc. manufactured by Shiraishi Calcium Co., Ltd. M.M. Huber's Polyplate P, Polyplate P01, Polyplate HMT, Engelhard's Nu clay, etc., Shiraishi Calcium Co., Ltd. Khaolax HS, Imerizu Minerals Japan Co., Ltd. Astra Plus, Contour 1500, Contour 2070, Contour Extreme, Capim DG, Capim NP, Engineered Deramikaolin, such as Capim CC.

  Examples of kaolin clay include Astra Scene, Astra Gross, Astra Coat, Beta Bright, Astra Glaze, Premier LX, Premier, Casey S, etc. manufactured by Imeris Minerals Japan Co., Ltd. 90, Kaoblite 90, Kao Gloss, Kaoblite, Kao Fine, etc., Union Clay RC-1 manufactured by Takehara Chemical Industry Co., Ltd. M.M. Examples include Huber 35, Huber 35B, Huber 80, Huber 80B, Huber 90, Huber 90B, Huber HG90, Huber TEK 2001, Polyloss 90, and Lithosperse 7005CS manufactured by Huber.

Among these, kaolin clay and deramikaolin are preferable from the viewpoint of further improving the suitability of the cutter.
The average particle diameter of kaolin contained in the first ink receiving layer (kaolin layer) is not particularly limited, but is preferably 0.3 to 15 μm and more preferably 1 to 10 μm from the viewpoint of improving cutter suitability.

In the first ink receiving layer (kaolin layer), the kaolin and other pigments other than kaolin may be used in combination as a pigment component.
Examples of other pigments include silica (silica fine particles), colloidal silica, titanium dioxide, barium sulfate, calcium silicate, zeolite, halloysite, mica, talc, calcium carbonate, magnesium carbonate, calcium sulfate, boehmite, pseudoboehmite, and the like. Can be mentioned.

The mass ratio of kaolin to the total pigment component in the first ink receiving layer (kaolin layer) is preferably 20 to 100 mass%, more preferably 50 to 100 mass%, from the viewpoint of further improving the cutter suitability.
Further, the mass ratio of kaolin to the total solid content in the first ink receiving layer (kaolin layer) is preferably 20 to 90 mass%, more preferably 30 to 80 mass% from the viewpoint of further improving the cutter suitability. preferable.

(Water-soluble resin)
The ink receiving layer contains at least one water-soluble resin.
Thereby, a pigment can be disperse | distributed more suitably and the coating-film intensity | strength can be improved more.
When the ink receiving layer has two or more layers, the water-soluble resins contained in these layers may be the same type or different types.

  Examples of the water-soluble resin include polyvinyl alcohol (including modified polyvinyl alcohols such as acetoacetyl modification, carboxy modification, itaconic acid modification, maleic acid modification, silica modification and amino group modification), methylcellulose, carboxymethylcellulose, starches ( Modified starch), gelatin, arabic gum, casein, styrene-maleic anhydride copolymer hydrolyzate, polyacrylamide, saponified vinyl acetate-polyacrylic acid copolymer, and the like. Examples thereof also include latex binders of synthetic polymers such as styrene / butadiene copolymer, vinyl acetate copolymer, acrylonitrile / butadiene copolymer, methyl acrylate / butadiene copolymer, and polyvinylidene chloride.

-Polyvinyl alcohol-
The polyvinyl alcohol includes polyvinyl alcohol obtained by saponifying a lower alcohol solution of polyvinyl acetate and derivatives thereof, and a saponified product of a copolymer of a monomer and vinyl acetate that can be copolymerized with vinyl acetate. It is. Here, as monomers that can be copolymerized with vinyl acetate, (anhydrous) maleic acid, fumaric acid, crotonic acid, itaconic acid, (meth) acrylic acid and other unsaturated carboxylic acids and esters thereof, ethylene, propylene, etc. Α-olefin, olefin sulfonic acid such as (meth) allyl sulfonic acid, ethylene sulfonic acid, sulfonic acid malate, (meth) allyl sulfonic acid soda, ethylene sulfonic acid soda, sulfonic acid soda (meth) acrylate, sulfonic acid soda ( Monoalkylmalates), olefinic sulfonic acid alkali salts such as sodium disulfonic acid alkylmalate, amide group-containing monomers such as N-methylolacrylamide, alkali acrylamide alkylsulfonic acid salts, and N-vinylpyrrolidone derivatives Can be mentioned.

Among the polyvinyl alcohols, polyvinyl alcohol having a saponification degree of 92 to 98 mol% (hereinafter sometimes referred to as “high saponification degree polyvinyl alcohol”) is particularly preferable.
If the saponification degree of polyvinyl alcohol is 92 mol% or more, a better halftone hue can be obtained, and an increase in the viscosity of the coating solution can be effectively suppressed, resulting in better coating stability. it can.
On the other hand, when the saponification degree of polyvinyl alcohol is 98 mol% or less, the ink absorbability can be further improved.
The saponification degree of polyvinyl alcohol is more preferably 93 to 97 mol%.
The polymerization degree of the high saponification degree polyvinyl alcohol is preferably 1500 to 3600, and more preferably 2000 to 3500. If the degree of polymerization is 1500 or more, cracking of the ink receiving layer can be more effectively suppressed. If it is 3600 or less, the viscosity increase of a coating liquid can be suppressed more effectively.

In the present invention, as the binder, a water-soluble resin other than the high saponification degree polyvinyl alcohol can be used in combination with the polyvinyl alcohol. Examples of water-soluble resins that can be used in combination include resins having a hydroxyl group as a hydrophilic structural unit, such as polyvinyl alcohol (PVA) having a saponification degree other than the above range, cation-modified polyvinyl alcohol, anion-modified polyvinyl alcohol, and silanol-modified polyvinyl. Alcohol, polyvinyl acetal, cellulose resin [methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC), hydroxypropyl cellulose (HPC), etc.], chitins, chitosans, starch; hydrophilic Polyethylene oxide (PEO), polypropylene oxide (PPO), polyethylene glycol (PEG), polyvinyl ether (PVE) A resin having an amide group or amide bond of a hydrophilic, polyacrylamide (PAAM), polyvinyl pyrrolidone (PVP) and the like. In addition, polyacrylic acid salts, maleic acid resins, alginic acid salts, gelatins and the like having a carboxyl group as a dissociable group can also be mentioned.
The ratio of the high saponification degree polyvinyl alcohol to the total amount of the high saponification degree polyvinyl alcohol and the water soluble resin when the high saponification degree polyvinyl alcohol and the above-mentioned water soluble resin are used in combination is preferably 1 to 30% by mass. 3 to 20% by mass is more preferable, and 6 to 12% by mass is particularly preferable.

  The content of the high saponification degree polyvinyl alcohol is to prevent a decrease in film strength and cracking at the time of drying due to an excess of the content, and due to an excess of the content, the voids are easily blocked by a resin. From the viewpoint of preventing the ink absorbency from being lowered due to the decrease in the porosity, the amount is preferably 9 to 40% by weight, more preferably 12 to 33% by weight with respect to the total solid content of the ink receiving layer. .

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

(Content ratio of inorganic fine particles and water-soluble resin)
In the ink receiving layer, the content ratio of the inorganic fine particles (x) to the water-soluble resin (y) [PB ratio (x / y), the mass of the inorganic fine particles relative to 1 part by mass of the water-soluble resin] is the film structure of the ink receiving layer. May also have a significant 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 ink jet recording medium when passing through the transport system of the ink jet printer, the ink receiving layer must have sufficient film strength. Further, when cutting into a sheet, the ink receiving layer needs to have sufficient film strength to prevent cracking and peeling of the ink receiving layer. From such a viewpoint, the PB ratio (x / y) is preferably 5/1 or less, and preferably 2/1 or more from the viewpoint of securing high-speed ink absorbability with an inkjet printer.

For example, a coating solution in which gas phase method silica having an average primary particle diameter of 20 nm or less and polyvinyl alcohol with a high saponification degree is completely dispersed in an aqueous solution with a PB ratio (x / y) of 2/1 to 5/1 is supported. When the coating layer is applied and dried, a three-dimensional network structure is formed in which the secondary particles of silica fine particles are chain units, the average pore diameter is 30 nm or less, the porosity is 50% to 80%, the pores A translucent porous film having a specific volume of 0.5 ml / g or more and a specific surface area of 100 m ² / g or more can be easily formed.

(Crosslinking agent)
The ink receiving layer in the invention preferably contains a crosslinking agent.
In the present invention, the ink receiving layer is preferably a porous layer cured by a crosslinking reaction of a water-soluble resin (for example, polyvinyl alcohol) with the crosslinking agent.

As the cross-linking agent, a suitable one may be appropriately selected in relation to the binder (for example, polyvinyl alcohol) contained in the ink receiving layer. Among them, a boron compound is preferable in that the cross-linking reaction is quick. , borax, boric acid, borates (eg, _{orthoborate, InBO 3, ScBO 3, YBO} 3, LaBO 3, Mg 3 (BO 3) 2, Co 3 (BO 3) 2, diborate salt ( For example, Mg ₂ B ₂ O ₅ , Co ₂ B ₂ O ₅ ), metaborate (eg, LiBO ₂ , Ca (BO ₂ ) ₂ , NaBO ₂ , KBO ₂ ), tetraborate (eg, Na ₂ B _{4 O 7 · 10H 2 O)} , can be cited pentaborate _{(eg, KB 5 O 8 · 4H 2} O, Ca 2 B 6 O 11 · 7H 2 O, CsB 5 O 5) or the like. Among them, In that it can cause a crosslinking reaction rapidly, borax, boric acid, borate salts are preferred, boric acid or borate salt is preferable, it is most preferable to use this in combination with polyvinyl alcohol.

  In the present invention, the cross-linking agent is preferably contained in an amount of 0.05 to 0.50 parts by mass, and 0.08 to 0.30 parts by mass with respect to 1.0 part by mass of the polyvinyl alcohol. It is more preferable. When the content of the crosslinking agent is within the above range, polyvinyl alcohol can be effectively crosslinked to prevent cracks and the like.

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

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

(Nitrogen-containing organic cationic polymer)
The ink receiving layer in the invention preferably contains at least one nitrogen-containing organic cationic polymer from the viewpoint of suppressing bleeding of the recorded image and from the viewpoint of dispersing inorganic fine particles.
The nitrogen-containing organic cationic polymer in the present invention is not particularly limited, but a polymer having a primary to tertiary amino group or a quaternary ammonium base is preferable.
The nitrogen-containing organic cation polymer is a nitrogen-containing organic cation which is a homopolymer of a monomer having a primary to tertiary amino group and a salt thereof or a quaternary ammonium base (nitrogen-containing organic cation monomer). Conjugated dienes such as polymers, nitrogen-containing organic cationic polymers obtained as copolymers or condensation polymers of the nitrogen-containing organic cationic monomers and other monomers, styrene-butadiene copolymers, methyl methacrylate-butadiene copolymers, etc. Acrylic polymers such as acrylic acid and methacrylic acid ester polymers or copolymers, acrylic acid and methacrylic acid polymers or copolymers; styrene-acrylic acid ester copolymers, styrene Styrene-acrylic polymers such as methacrylate copolymers; ethylene vinyl acetate copolymer Vinyl polymer and the like; the urethane polymer or the like having a urethane bond include a nitrogen-containing organic cation polymers obtained by cationizing modified with a compound containing a cationic group.

  Examples of the nitrogen-containing organic cation 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 -Vinylbenzylammonium chloride, N, N-dimethyl-Nn-octyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N-benzyl-Np-vinylbenzylammonium chloride, N, N- Ethyl-N-benzyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N- (4-methyl) benzyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N-phenyl-N -P-vinylbenzylammonium chloride;

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

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

  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. In addition, examples of copolymerizable monomers include N-vinylimidazole and N-vinyl-2-methylimidazole. In addition, a polymerization unit such as N-vinylacetamide, N-vinylformamide or the like, which is converted into a vinylamine unit by hydrolysis after polymerization, and a salt thereof can be used.

  Examples of the other monomer that can be copolymerized (or polycondensed) with the nitrogen-containing organic cation monomer include basic groups such as primary to tertiary amino groups and salts thereof, or quaternary ammonium bases. Or the monomer which does not contain a cationic part, does not show interaction with the dye in an inkjet ink, or interaction is substantially small is mentioned. For example, (meth) acrylic acid alkyl ester; (meth) acrylic acid cycloalkyl ester such as cyclohexyl (meth) acrylic acid; (meth) acrylic acid aryl ester such as phenyl (meth) acrylate; benzyl (meth) acrylic acid Aralkyl esters of styrene; vinyl aromatics such as styrene, vinyl toluene and α-methyl styrene; vinyl esters such as vinyl acetate, vinyl propionate and vinyl versatate; allyl esters such as allyl acetate; vinylidene chloride, vinyl chloride, etc. Halogen-containing monomers, vinyl cyanides 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 other monomers can also be used alone or in combination of two or more.

  Moreover, as a monomer which comprises a urethane type polymer, the polyvalent isocyanate compound (For example, 2, 4-tolylene diisocyanate, 2, 6-tolylene diisocyanate, m-phenylene diisocyanate, 4,4 which has two or more isocyanate groups). '-Diphenylmethane diisocyanate, hexamethylene diisocyanate, octamethylene diisocyanate, 1,4-cyclohexylene diisocyanate, isophorone diisocyanate, 1,3-bis (isocyanatemethyl) -cyclohexane, 1,5-diisocyanate-2-methylpentane, hydrogenated Xylylene diisocyanate, hydrogenated 4,4′-diphenylmethane diisocyanate, etc.) and a compound that can react with an isocyanate group to form a urethane bond (eg, glycerin) Polyol compounds such as 1,6-hexanediol, triethanolamine, polypropylene glycol, polyethylene glycol, bisphenol A, hydroquinone; succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, maleic anhydride, fumaric acid, 1 , 3-cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalene Acid, biphenylcarboxylic acid, sorbitol, sucrose, aconitic acid, trimellitic acid, hemimellitic acid, phosphoric acid, ethylenediamine, propylenediamine, diethylenetriamine, triisopropanolamine, pyrogallol, Such as hydroxybenzoic acid, hydroxyphthalic acid, 1,2,3-propanetrithiol, ethylenediamine, propylenediamine, hexamethylenediamine, phenylenediamine, tolylenediamine, diphenyldiamine, diaminodiphenylmethane, diaminocyclohexylmethane, piperazine, isophoronediamine Such diamines; and hydrazine).

  Furthermore, examples of the compound that introduces a cationic group into a copolymer or condensate having no cationic group include alkyl halides and methylsulfuric acid.

Among the nitrogen-containing organic cationic polymers described above, from the viewpoint of suppressing bleeding, cationic polyurethanes and cationic polyacrylates described in JP-A No. 2004-167784 are preferable, and cationic polyurethanes are more preferable.
Examples of commercially available products of cationic polyurethane include “Superflex 650”, “Superflex 650-5”, “F-8564D”, and “F-8570D” manufactured by Daiichi Kogyo Seiyaku Co., Ltd., and Nikka Chemical Co., Ltd. , “Neofix IJ-150” and the like.

From the viewpoint of pigment dispersion, polydiallyldimethylammonium chloride and polymethacryloyloxyethyl-β-hydroxyethyldimethylammonium chloride derivatives are preferable, and polydiallyldimethylammonium chloride is more preferable.
Examples of commercially available products include “Charol DC902P” manufactured by Daiichi Kogyo Seiyaku Co., Ltd.

  Further, as the nitrogen-containing organic cationic polymer, cation-modified self-emulsifying polymers described in JP-A-2007-223119, paragraph numbers 0018 to 0046 can also be used.

Further, these nitrogen-containing organic cationic polymers can be used in any form of a water-soluble polymer, water-dispersible latex particles, and an aqueous emulsion.
Examples of the aqueous emulsion include a conjugated diene copolymer emulsion; an acrylic polymer emulsion; a styrene-acrylic polymer emulsion; a vinyl polymer emulsion; And those obtained by cationizing the emulsion surface with a cationic surfactant, polymerized under cationic polyvinyl alcohol, and distributing the polyvinyl alcohol on the emulsion surface. Among these cationic emulsions, a cationic polyurethane emulsion whose main component is a urethane emulsion is preferable.

  In the present invention, the nitrogen-containing organic cationic polymer contained in the ink receiving layer forming coating solution is preferably a cationic polyurethane, more preferably a cationic polyurethane emulsion, from the viewpoint of suppressing bleeding.

(Water-soluble polyvalent metal salt)
The ink jet recording medium of the present invention can contain a water-soluble polyvalent metal salt, if necessary.
Examples of the water-soluble polyvalent metal salt include water-soluble salts of metals selected from calcium, barium, manganese, copper, cobalt, nickel, aluminum, iron, zinc, zirconium, chromium, magnesium, tungsten, and molybdenum.
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, aluminum sulfate, aluminum sulfite, aluminum thiosulfate, polyaluminum chloride, aluminum nitrate nonahydrate, aluminum chloride hexahydrate, aluminum lactate, ferrous bromide, Ferrous chloride, ferric chloride, ferrous sulfate, ferric sulfate, phenol sulfo Zinc acid, zinc bromide, zinc chloride, zinc nitrate hexahydrate, zinc sulfate, zirconium acetate, zirconium chloride, chlorinated zirconium oxide octahydrate, hydroxy zirconium chloride, zirconyl acetate, zirconyl nitrate, zirconyl octylate, hydroxy chloride Zirconyl, chromium acetate, chromium sulfate, magnesium sulfate, magnesium chloride hexahydrate, magnesium citrate nonahydrate, sodium phosphotungstate, sodium tungsten citrate, 12 tungstophosphoric acid n hydrate, 12 tungstosilicic acid 26 water Japanese hydrate, molybdenum chloride, 12 molybdophosphoric acid n hydrate and the like.
Among these, water and water-soluble salts of group IVa elements (zirconium, titanium, etc.) of the periodic table are particularly preferable.
Here, “water-soluble” means that 1% by mass or more dissolves in water at room temperature and normal pressure.

The ink receiving layer in the invention preferably contains a water-soluble aluminum compound.
By using a water-soluble aluminum compound, it is possible to improve the water resistance and aging resistance of the formed image.
As a water-soluble aluminum compound, for example, as an inorganic salt, aluminum chloride or a hydrate thereof, aluminum sulfate or a hydrate thereof, ammonium alum and the like are known. Furthermore, there is a basic polyaluminum hydroxide compound which is an inorganic aluminum-containing cationic polymer. Among these, a basic polyaluminum hydroxide compound is preferable.

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

[Al ₂ (OH) _n Cl _6-n ] _m (5 <m <80, 1 <n <5) (Formula 1)
[Al (OH) ₃ ] _n AlCl ₃ (1 <n <2) (Formula 2)
Al _n (OH) _m Cl _(3n-m) (0 <m <3n, 5 <m <8) (Formula 3)

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

  In the ink receiving layer of the present invention, the content of the water-soluble aluminum compound is preferably from 0.1 to 20% by weight, more preferably from 1 to 8% by weight, particularly 2 as the total solid content constituting the ink receiving layer. ˜4% by weight is most preferred. When the content of the water-soluble aluminum compound is in the range of 2 to 4% by mass, an effect of improving glossiness, water resistance, gas resistance and light resistance can be obtained.

The ink receiving layer in the invention preferably contains a zirconium compound.
The effect of improving water resistance can be obtained by using a zirconium compound.
The zirconium compound used in the present invention is not particularly limited, and various compounds can be used. For example, zirconyl acetate, zirconium chloride, zirconium oxychloride, hydroxy zirconium chloride, zirconium nitrate, basic zirconium carbonate, zirconium hydroxide, Zirconium carbonate / ammonium, zirconium carbonate / potassium, zirconium sulfate, zirconium fluoride compound and the like can be mentioned. Zirconyl acetate is particularly preferable.

  In the ink receiving layer of the present invention, the content of the zirconium compound is preferably 0.05 to 5.0% by mass, more preferably 0.1 to 3.0% by mass, based on the total solids constituting the ink receiving layer. Particularly preferred is 0.5 to 2.0 mass%. When the content of the zirconium compound is in the range of 0.5 to 2.0% by mass, it is possible to improve water resistance without reducing the ink absorbency.

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

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

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

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

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

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

  These anti-fading agents may be used alone or in combination of two or more. The anti-fading agent may be water-solubilized, dispersed, emulsified, or included in microcapsules. The addition amount of the antifading agent is preferably 0.01 to 10% by mass of the ink receiving layer forming liquid.

  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 a water-soluble one, 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), and triglyceride. Ethylene glycol monobutyl ether, glycerin monomethyl ether, 1,2,3-butanetriol, 1,2,4-butanetriol, 1,2,4-pentanetriol, 1,2,6-hexanetriol, thiodiglycol, tri Examples include alcohols such as ethanolamine 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 forming liquid is preferably 0.05 to 1% by mass, particularly preferably 0.1 to 0.6% by mass.
Further, for the purpose of enhancing the dispersibility of the inorganic fine particles, various inorganic salts and pH adjusting agents may contain acids, alkalis and the like.
Further, for the purpose of suppressing surface frictional charge and peeling charge, the metal oxide fine particles having electronic conductivity may contain various matting agents for the purpose of reducing the surface frictional characteristics.

The layer thickness of the ink receiving layer of the present invention described above is not particularly limited. For example, in the case of a two-layer structure, the following layer thickness is preferable.
The layer thickness (per one side) of the first ink receiving layer is preferably 1 to 50 μm, more preferably 2 to 30 μm, from the viewpoint of absorbability and suppression of fingerprint marks.
The layer thickness (per side) of the second ink receiving layer is preferably 5 to 30 μm, more preferably 10 to 30 μm, from the viewpoints of absorptivity, density and gloss.
The total thickness (per side) of the ink receiving layer including the first ink receiving layer and the second ink receiving layer is preferably 10 to 60 μm, more preferably 10 to 40 μm, from the viewpoint of absorbability.

<Intermediate layer>
In the ink jet recording medium of the present invention, an intermediate layer can be provided between the support and the ink receiving layer in both the single-sided product and the double-sided product having the ink receiving layer on one side and both sides. It is preferable from the viewpoint of improving the printing density that the intermediate layer contains the aqueous lubricant.
By including an aqueous lubricant in the intermediate layer, the printing density can be improved.
The intermediate layer preferably contains a binder, and may further contain a pigment such as inorganic fine particles as necessary.
As the binder and the inorganic fine particles, a water-soluble resin and inorganic fine particles that can be contained in the ink receiving layer can be used.
In addition to the above-mentioned components, the intermediate layer further includes pigments, ultraviolet absorbers, antioxidants, pigment dispersants, antifoaming agents, leveling agents, preservatives, fluorescent brighteners, viscosity stabilizers, pH adjusters. Various known additives such as an agent, glass beads (for example, GB603M, manufactured by Toshiba Valotinenen Co., Ltd.) and the like can also be added.

<Other layers>
The ink jet recording medium of the present invention is a function in which a layer other than the ink receiving layer, for example, a top layer (for example, a colloidal silica layer), a cushioning property, an antistatic property and the like are provided on the support. A layer, an interlayer mixing suppression layer (barrier layer), and the like.

<Support>
The support in the ink jet recording medium of the present invention is not limited, but a water-impermeable support is preferable in that deformation such as curling accompanying image recording is suppressed.

Here, “water impermeability” refers to the property of not absorbing water or having an amount of water absorption of 0.3 g / m ² or less.

-Water impermeable support-
In the present invention, the glossiness of the surface of the water-impermeable support is not particularly limited, but it is possible to produce a semi-gloss product using either a high-gloss support or a low-gloss support. From the viewpoint of expanding the width, it is preferably 40% or more, more preferably 45% or more and 95% or less, and more preferably 50% or more and 85% or less.
Furthermore, it is particularly preferable that the glossiness of both surfaces of the water-impermeable support is within the above range.

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

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

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

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

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

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

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

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

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

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

  The polyolefin (preferably polyethylene) covering both sides of the base paper is mainly low-density polyethylene (LDPE) and / or high-density polyethylene (HDPE), but other LLDPE, polypropylene and the like can also be used in part.

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

Polyolefin resin-coated paper (preferably polyethylene resin-coated paper) can be used as glossy paper, or can be obtained with ordinary photographic printing paper by performing a so-called molding process when polyethylene is melt-extruded onto the base paper surface for coating. Those with a matte surface or silky surface can be used.
The polyolefin resin layers provided on both sides of the base paper may be the same (same composition, same film thickness, etc.) or different (different compositions, different film thicknesses, etc.).

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

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

≪Inkjet recording medium manufacturing method≫
The method for producing the ink jet recording medium of the present invention described above is not particularly limited. However, in the case of only the ink receiving layer (for example, the above-described aspects (1-1) and (2-1)), for example, water It can be manufactured by a manufacturing method having a step of forming an ink receiving layer by applying a coating liquid containing the water-based lubricant, inorganic fine particles and water-soluble resin on one or both surfaces of the non-permeable support.

  In the case where the ink jet recording medium of the present invention has a single ink-receiving layer (for example, the above-described aspects (1-2, 1-5) and (2-2, 2-5)), A step of forming an ink receiving layer by applying a coating liquid containing an inorganic fine particle and a water-soluble resin after coating a coating liquid such as an intermediate layer containing the aqueous lubricant on one or both surfaces of a permeable support. It can manufacture with the manufacturing method which has.

In addition, when the inkjet recording medium of the present invention has two ink-receiving layers (for example, the above-described aspects ((1-3, 1-4), (2-3, 2-4)), for example, water The first coating liquid containing at least the water-based lubricant, kaolin or silica and the second coating liquid containing silica are seen from both sides of the non-permeable support from the water-impermeable support side. It can be manufactured by a manufacturing method having a step of forming an ink receiving layer by applying (preferably simultaneous multi-layer application) in an arrangement to be a first coating liquid and a second coating liquid.
The method for producing an ink jet recording medium of the present invention may further include other steps as necessary.
In the above production method, the ink receiving layer, the intermediate layer, the water-impermeable support and the like are as described in the above description of the ink jet recording medium, and the preferred ranges are also the same.

Hereinafter, the case where the ink jet recording medium of the present invention has two ink receiving layers will be described in more detail.
In the method for producing an inkjet recording medium of the present invention, the ink receiving layer is formed by applying the first coating liquid or the second coating liquid, which is a coating liquid for forming an ink receiving layer, on a water-impermeable support or already. It can form by apply | coating on the formed ink receiving layer, forming an application layer, and drying this.
For example, when the ink receiving layer of the inkjet recording medium of the present invention has a two-layer structure, the first ink receiving layer is formed by applying the first coating liquid on a water-impermeable support. The second ink receiving layer can be formed by applying the second coating liquid on the formed first ink receiving layer.

<Application process>
In the method for producing an ink jet recording medium of the present invention, the first coating liquid and the second coating liquid are coated in an arrangement that becomes the first coating liquid and the second coating liquid when viewed from the water-impermeable support side. It can manufacture by having a process (henceforth a "coating process") to do.
By performing this application on one or both surfaces of the water-impermeable support, an ink receiving layer can be formed on one or both surfaces of the water-impermeable support.
As a method of applying the first coating liquid and the second coating liquid (and other coating liquids used as necessary), the first coating liquid and the second coating liquid as viewed from the water-impermeable support side. There is no particular limitation as long as it is a coating method in which liquids are arranged in order.
For example, a sequential coating method (for example, a blade coater, an air knife coater, a roll coater, a bar coater, a gravure coater, a reverse coater, etc.) that coats one layer at a time, or a plurality of layers constituting the ink receiving layer may be used. A simultaneous multi-layer coating method (for example, a slide bead coater, a slide curtain coater, or the like) that coats almost simultaneously without providing a drying step may be used. Alternatively, for example, “Wet-On-Wet method” (hereinafter, “WOW method”) described in paragraph numbers 0016 to 0037 of JP-A-2005-14593 may be used.

Among the above, the simultaneous multilayer coating method is preferably used from the viewpoint that the characteristics required for each layer can be obtained efficiently and the production efficiency is excellent. That is, in the simultaneous multi-layer coating, by laminating each layer in a wet state, the component contained in each layer, for example, the upper layer (for example, the second ink receiving layer in the inkjet recording medium of the present invention) is changed to the lower layer (for example, the present invention). This is presumably because the composition of each layer is well maintained even after drying.
The simultaneous multilayer coating can be performed using a known coating apparatus, and examples thereof include a slide bead coater, a curtain flow coater, and an extrusion die coater.

  In the present invention, if necessary, another coating solution may be applied onto the second coating solution. Moreover, a barrier layer coating solution or an intermediate layer coating solution may be interposed between the coating solutions.

Here, a preferable coating amount of each coating solution will be described.
As solid content application amount of a 1st coating liquid, 0.5-30 g / m < ² > is preferable per one surface, and 1-20 g / m < ² > is more preferable.
Moreover, as solid content application amount of a 2nd coating liquid, 2-30 g / m < ² > is preferable per one surface, and 5-20 g / m < ² > is more preferable.
Hereinafter, the first coating solution, the second coating solution, and other coating solutions used as necessary will be described.

(First coating solution)
The first coating liquid may be an embodiment containing at least one kaolin or an embodiment containing at least one silica.
The first coating solution may further contain other components such as a binder, a crosslinking agent, a nitrogen-containing organic cationic polymer, a water-soluble aluminum compound, a zirconium compound, and the like.
The kaolin or silica contained in the first coating solution and other components used as necessary are as described in the description of the ink receiving layer, and the preferred ranges are also the same.
Further, the content of kaolin in the case of using kaolin in the first coating liquid is not particularly limited, but is preferably 20 to 90% by mass with respect to the total solid content of the first coating liquid. More preferably, it is -80 mass%.
In the present invention, the total solid content in the first coating liquid refers to all components excluding water from the first coating liquid. The same applies to other liquids.

  The first coating solution is preferably acidic, and the pH is preferably 5.0 or less, more preferably 4.5 or less, and even more preferably 4.0 or less. The pH of the first coating solution can be adjusted by appropriately selecting the type and addition amount of the nitrogen-containing organic cationic polymer. Moreover, you may adjust by adding an organic or inorganic acid. When the pH of the first coating solution is 5.0 or less, for example, the crosslinking reaction of the water-soluble resin (binder) by the crosslinking agent (particularly boron compound) in the first coating solution can be more sufficiently suppressed. it can.

-Example of preparation method of first coating liquid-
In the present invention, the first coating liquid can be prepared, for example, as follows.
That is, kaolin, a dispersant, and a zirconium compound are added to water (for example, kaolin in water is 10 to 20% by mass), and a high-speed rotating wet colloid mill (for example, “Clearmix” manufactured by M Technique Co., Ltd.). ) Or a liquid-liquid collision type disperser (Ultimizer, manufactured by Sugino Machine Co., Ltd.), and then an aqueous polyvinyl alcohol (PVA) solution (for example, PVA having a mass of about 1/3 of the kaolin). And a nitrogen-containing organic cationic polymer, and further by adding the water-soluble aluminum compound and dispersing.
The water-soluble aluminum compound may be added by in-line mixing immediately before coating.
Moreover, a liquid-liquid collision type disperser (for example, an optimizer manufactured by Sugino Machine Co., Ltd.) can also be used for the dispersion.
The obtained coating liquid is in a uniform sol state, and a porous ink-receiving layer having a three-dimensional network structure can be formed by applying the coating liquid onto a support by the following coating method and drying it.

  The aqueous dispersion comprising the kaolin and the dispersant may be prepared by preparing a kaolin aqueous dispersion in advance, and adding the aqueous dispersion to the aqueous dispersant solution. Or may be mixed at the same time. Further, instead of the kaolin aqueous dispersion, powder kaolin may be added to the aqueous dispersion as described above.

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

In addition, a chaotic polymer can be used as the dispersant. Examples of the chaotic polymer include mordant examples described in paragraphs [0138] to [0148] of JP-A-2006-321176. It is also preferable to use a silane coupling agent as the dispersant.
The amount of the dispersant added to the fine particles is preferably 0.1% to 30%, more preferably 1% to 10%.

(Second coating liquid)
The 2nd coating liquid in this invention contains at least 1 sort (s) of a silica.
The second coating solution may further contain other components such as a binder, a crosslinking agent, a nitrogen-containing organic cationic polymer, a water-soluble aluminum compound, a zirconium compound, and the like.
The silica and other components contained in the second coating liquid are as described in the description of the ink receiving layer, and the preferred ranges are also the same.
Moreover, there is no restriction | limiting in particular as content rate of the silica in a 2nd coating liquid, However, It is preferable that it is 50-85 mass% with respect to the total solid of a 2nd coating liquid. More preferably.

  The method for preparing the second coating solution is not particularly limited. For example, the second coating solution can be prepared by replacing kaolin with silica in the first coating solution preparation method.

  As with the first coating solution, the second coating solution is preferably acidic, and the pH is preferably 5.0 or less, more preferably 4.5 or less. More preferably, it is 0 or less. This pH can be adjusted by appropriately selecting the type and amount of the nitrogen-containing cationic polymer. Moreover, you may adjust by adding an organic or inorganic acid. When the pH of the second coating solution is 5.0 or less, for example, the binder crosslinking reaction by the crosslinking agent (particularly boron compound) in the second coating solution can be more sufficiently suppressed.

<Curing process>
In the method for producing an ink jet recording medium of the present invention, the coating layer formed by coating the first coating liquid and the second coating liquid,
(1) At the same time as applying at least the first coating liquid and the second coating liquid,
(2) At least during the drying of the coating layer formed by applying the first coating solution and the second coating solution, and before the coating layer exhibits reduced-rate drying,
In any of the cases, a curing step of applying a liquid containing a basic compound and crosslinking and curing the coating layer may be provided.

Examples of the method for applying the “liquid containing a basic compound” at the same time as “(1) at least the first coating liquid and the second coating liquid are applied” include the first coating liquid and the second coating liquid. It is preferable that the coating solution (the other coating solution if necessary) and the “liquid containing a basic compound” are simultaneously applied (multilayer coating) in this order from the support side.
Alternatively, after the first coating liquid is applied, the second coating liquid and the “liquid containing a basic compound” are simultaneously applied onto the applied first coating liquid (hereinafter referred to as “simultaneous multilayer coating”). You may say).
The simultaneous coating (simultaneous multilayer coating) can be performed using a known coating device such as an extrusion die coater or a curtain flow coater.

“(2) Basic compound in the middle of drying of the coating layer formed by applying at least the first coating solution and the second coating solution and before the coating layer exhibits reduced-rate drying” The method of applying the “liquid containing” is a method called “Wet-On-Wet method” or “WOW method”. Details of the “Wet-On-Wet method” are described, for example, in paragraph numbers [0016] to [0037] of JP-A-2005-14593.
In the present invention, the first coating liquid and the second coating liquid (and other coating liquids as necessary) are simultaneously applied (simultaneous multi-layer coating) so as to be in this order from the support side. Alternatively, after forming the coating layer by coating one layer at a time, before the coating layer is in the course of drying, and before the coating layer exhibits reduced-rate drying, (i) further “basic compound” (Ii) a method of spraying the “liquid containing a basic compound” by spraying or the like, (iii) the support on which the coating layer is formed in the “liquid containing a basic compound” And a method of immersing in water.

  In the above (i), as a coating method for applying the “liquid containing a basic compound”, for example, curtain flow coater, extrusion die coater, air doctor coater, bread coater, rod coater, knife coater, squeeze coater, reverse A known coating method such as a roll coater or a bar coater can be used. However, it is preferable to use a method in which the coater does not directly contact an already formed coating layer, such as an extrusion die coater, a curtain flow coater, a bar coater or the like.

  In the cross-linking curing step, “before the coating layer comes to show reduced-rate drying” usually means an ink-receiving layer coating solution (in the present invention, the first coating solution and the second coating solution ( Furthermore, it refers to a process for several minutes immediately after the application of other coating liquids)) as necessary, during which the content of the solvent (dispersion medium) in the coated coating layer decreases in proportion to time. The phenomenon of “constant rate drying” is shown. About the time which shows this "constant rate drying", it describes in chemical engineering handbook (pages 707-712, Maruzen Co., Ltd. issue, October 25, 1980), for example.

  As a condition for the above-mentioned “drying until the coating layer exhibits reduced rate drying”, it is generally carried out at 40 to 180 ° C. for 0.5 to 10 minutes (preferably 0.5 to 5 minutes). The drying time naturally varies depending on the coating amount, but usually the above range is appropriate.

(Liquid containing basic compound)
Here, the “liquid containing a basic compound” in the crosslinking curing step will be described.
~ Basic compounds ~
The “liquid containing a basic compound” in the present invention contains at least one basic compound.
Basic compounds include ammonium salts of weak acids, alkali metal salts of weak acids (eg, lithium carbonate, sodium carbonate, potassium carbonate, lithium acetate, sodium acetate, potassium acetate, etc.), alkaline earth metal salts of weak acids (eg, carbonate Magnesium, barium carbonate, magnesium acetate, barium acetate, etc.), hydroxyammonium, primary to tertiary amines (eg, triethylamine, tripropylamine, tributylamine, trihexylamine, dibutylamine, butylamine, etc.), primary to tertiary anilines ( For example, diethylaniline, dibutylaniline, ethylaniline, aniline, etc.), pyridine which may have a substituent (for example, 2-aminopyridine, 3-aminopyridine, 4-aminopyridine, 4- (2-hydroxyethyl) -Aminopyrid Etc.), and the like.

  In addition to the basic compound, other basic substances and / or salts thereof may be used in combination with the basic compound. Examples of other basic substances include ammonia, primary amines such as ethylamine and polyallylamine, secondary amines such as dimethylamine, tertiary amines such as N-ethyl-N-methylbutylamine, and alkali metals. And alkaline earth metal hydroxides.

Among the above, ammonium salts of weak acids are particularly preferable. The weak acid is an inorganic acid or an organic acid described in Chemical Handbook Fundamentals II (Maruzen Co., Ltd.) or the like and having an pKa of 2 or more. Examples of the weak acid ammonium salt include ammonium carbonate, ammonium hydrogen carbonate, ammonium borate, ammonium acetate, and ammonium carbamate. However, it is not limited to these. Among these, ammonium carbonate, ammonium hydrogen carbonate, and ammonium carbamate are preferable, and are effective in that ink bleeding can be reduced without remaining in the layer after drying.
Two or more basic compounds can be used in combination.

  The content of the basic compound (particularly the ammonium salt of a weak acid) in the “liquid containing the basic compound” is 0.5 to 0.5% relative to the total mass (including the solvent) of the “liquid containing the basic compound”. 10 mass% is preferable, More preferably, it is 1-5 mass%. When the content of the basic compound (particularly the ammonium salt of the weak acid) is particularly in the above range, a sufficient degree of curing can be obtained, and the ammonia concentration becomes too high without impairing the working environment.

~ Metal compound ~
The “liquid containing a basic compound” in the present invention preferably contains at least one metal compound.

  As the metal compound contained in the “liquid containing a basic compound”, those that are stable under basicity can be used without limitation, and the above-mentioned water-soluble polyvalent metal salts, metal complex compounds, inorganic oligomers, or inorganic polymers can be used. Any of these may be used. For example, zirconium compounds and compounds listed as inorganic mordants in paragraphs [0100] to [0101] of JP-A-2005-14593 are suitable. Examples of the metal complex compound include metal complexes described in “Chemistry Review No. 32 (1981)” edited by the Chemical Society of Japan, “Coordination Chemistry Review”, Vol. 84, pages 85-277. (1988) and JP-A-2-182701, transition metal complexes containing a transition metal such as ruthenium can be used.

  Among the above, zirconium compounds and zinc compounds are preferable, and zirconium compounds are particularly preferable. Examples of the zirconium compound include zirconium carbonate / ammonium, zirconium nitrate / ammonium, zirconium carbonate / potassium, zirconium citrate / ammonium citrate, zirconyl stearate, zirconyl octylate, zirconyl nitrate, zirconium oxychloride, and zirconium zirconium hydroxychloride. Particularly preferred is zirconium ammonium carbonate. Moreover, two or more metal compounds (preferably containing a zirconium compound) may be used in combination in the “liquid containing a basic compound”.

  As content in the "liquid containing a basic compound" of the said metal compound (especially zirconium compound), it is 0.05-5 mass% with respect to the total mass (a solvent is included) of "the liquid containing a basic compound". Is more preferable, and 0.1 to 2% by mass is more preferable. By setting the content of the metal compound (especially zirconium compound) in the above range, the coating layer can be sufficiently hardened, and the mordant ability is lowered, so that a sufficient printing density cannot be obtained, or beading is not achieved. It does not occur, and the working environment is not deteriorated due to the concentration of a basic compound such as ammonia becoming too high. Two or more metal compounds can be used in combination, and when other mordant components to be described later are used in combination with a metal compound other than the metal compound, the total amount is within the above range and does not impair the effects of the present invention. It can be contained in a range.

From the viewpoint of image density and ozone resistance, the “liquid containing a basic compound” preferably contains the aforementioned magnesium salt as a metal compound. As the magnesium salt, magnesium chloride is particularly preferable.
In this case, the addition amount of the magnesium salt is preferably 0.1 to 1% by mass and more preferably 0.15 to 0.5% by mass with respect to the total mass of the “liquid containing a basic compound”.

The “liquid containing a basic compound” can contain a crosslinking agent and other mordant components as necessary.
The “liquid containing a basic compound” can promote dura mater when used as an alkaline solution, and is preferably adjusted to pH 7.1 or higher, more preferably pH 8.0 or higher, and particularly preferably pH 9.0. That's it. When the pH is 7.1 or more, a crosslinking reaction of a water-soluble resin (binder) that may be contained in the first coating solution and / or the second coating solution can be further promoted, and bronzing and ink reception can be performed. Cracks in the layer can be more effectively suppressed.

  The “liquid containing a basic compound” includes, for example, ion-exchanged water, a metal compound (eg, zirconia compound; eg, 1 to 5%) and a basic compound (eg, ammonium carbonate; eg, 1 to 5%), It can be prepared by adding para-toluenesulfonic acid (for example, 0.5 to 3%) as necessary and stirring sufficiently. In addition, all "%" of each composition means solid content mass%.

  In addition, water, an organic solvent, or a mixed solvent thereof can be used as a solvent used for preparing the “liquid containing a basic compound”. Examples of the organic solvent that can be used for coating include alcohols such as methanol, ethanol, n-propanol, i-propanol, and methoxypropanol, ketones such as acetone and methyl ethyl ketone, tetrahydrofuran, acetonitrile, ethyl acetate, and toluene. .

<Cooling process, drying process>
In the method for producing an ink jet recording medium of the present invention, the coating layer formed in the coating layer forming step is any one of a temperature of the first coating liquid at the time of coating and a temperature of the second coating liquid at the time of coating. A step of cooling so as to decrease by 5 ° C. or more with respect to the lower one (hereinafter also referred to as “cooling step”) and a step of drying the cooled coating layer to form an ink receiving layer (hereinafter referred to as “drying step”) May be included).

As a method for cooling the coating layer in the cooling step, the support on which the coating layer is formed is cooled for 5 to 30 seconds in a cooling zone maintained at 0 to 10 ° C. (more preferably 0 to 5 ° C.). Is preferred.
Here, the temperature of the coating layer is measured by measuring the temperature of the film surface.

<Other processes>
In the present invention, 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, thereby surface smoothness. It is possible to improve glossiness, transparency and coating strength. However, the calendar process may cause a decrease in the porosity (that is, the ink absorptivity may be decreased), so it is necessary to set conditions under which the decrease in the porosity is small.

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

  The present invention will be described more specifically with reference to the following examples. The scope of the present invention is not limited to the specific examples shown below. Unless otherwise specified, “part” and “%” are based on mass.

[Example 1]
≪Preparation of inkjet recording medium≫
<Production of water-impermeable support>
50 parts of LBKP made of acacia and 50 parts of LBKP made of aspen were each beaten to 300 ml of Canadian freeness by a disc refiner to prepare a pulp slurry.
Next, in the pulp slurry obtained above, per starch, cationic starch (CAT0304L manufactured by NSC Japan) 1.3%, anionic polyacrylamide (Polyaclon ST-13 manufactured by Seiko Chemical Co., Ltd.) 0.15%, alkyl ketene dimer (Arakawa Chemical Size Pine K) 0.29%, Epoxidized behenamide 0.29%, Polyamide polyamine epichlorohydrin (Arakawa Chemical Co., Ltd. Arafix 100) 0.32%, then added antifoam 0.12% Was added.

In the process of making the pulp slurry prepared as above with a long paper machine and pressing the felt surface of the web against the drum dryer cylinder through the dryer canvas for drying, the tensile force of the dryer canvas is 1.6 kg / kg. After drying by setting to cm, 1 g / m ² of polyvinyl alcohol (KL-118 manufactured by Kuraray Co., Ltd.) was applied to both sides of the base paper with a size press and dried to perform calendar treatment. The base paper was made with a basis weight of 157 g / m ² to obtain a base paper (base paper) having a thickness of 157 μm.

One side of the obtained base paper is subjected to a corona discharge treatment, and on one side, 0.93 g / m ² of polyethylene having 10% by mass of titanium oxide is adjusted to 24 g / m ^2. Extrusion coating was performed at 320 ° C. using a melt extruder.
Subsequently, the other surface was also subjected to corona discharge treatment, and on the other surface side, polyethylene having a density of 0.93 g / m ² having 10% by mass of titanium oxide was melt-extruded so as to be 24 g / m ^2. Was extrusion coated at 320 ° C.
From the above, a polyethylene resin-coated paper (water-impermeable support) in which both sides of the base paper were coated with polyethylene was obtained.

<Preparation of receiving layer coating solution 1>
(1) Gas phase method silica fine particles, (2) ion-exchanged water, (3) “Charol DC-902P”, and (4) “ZA-30” shown in the following composition are mixed to obtain a liquid. After dispersion using a liquid collision type disperser (Ultimizer, manufactured by Sugino Machine Co., Ltd.), the obtained dispersion was heated to 45 ° C. and held for 20 hours. Thereafter, (5) boric acid, (6) polyvinyl alcohol solution, and (7) cation-modified polyurethane were added to the dispersion at 30 ° C. to prepare a receiving layer coating solution 1.
The mass ratio between the silica fine particles and the water-soluble resin (PB ratio = (1) :( 6)) was 4.9: 1, and the pH of the receiving layer coating solution 1 was 3.4, indicating acidity.

-Composition of receiving layer coating solution 1-
(1) Vapor phase silica fine particles (inorganic fine particles) 8.9 parts (AEROSIL300SF75, manufactured by Nippon Aerosil Co., Ltd.)
(2) Ion-exchanged water: 47.3 parts (3) “Charol DC-902P” (51.5% aqueous solution) 0.78 parts (dispersant, nitrogen-containing organic cationic polymer, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) )
(4) "ZA-30": 0.48 parts (Daiichi Rare Element Chemical Co., Ltd., zirconyl acetate)
(5) Boric acid (7.5% aqueous solution) ... 4.38 parts (6) Polyvinyl alcohol (water-soluble resin) solution ... 26.0 parts-Composition of the solution-
・ JM33 (polyvinyl alcohol (PVA); degree of saponification 95.5%, degree of polymerization 3300, manufactured by Nippon Acetate / Poval) 1.81 parts ・ HPC-SSL (water-soluble cellulose, manufactured by Nippon Soda Co., Ltd.) 0.08 parts ・ Ion-exchanged water ... 22.62 parts ・ SC-P400 (Sakamoto Chemical Co., Ltd.) ... 0.89 parts ・ Emulgen 109P (surfactant, manufactured by Kao Corporation). 6 parts (7) Cation-modified polyurethane (Superflex 650-5 (25% solution), manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) ... 1.8 parts

<Formation of ink receiving layer>
After performing corona discharge treatment on one surface of the water-impermeable support obtained above, the receiving layer coating solution 1 is applied to the one surface with an extrusion die coater as follows. Thus, a coating layer was formed.
Specifically, the receiving layer coating solution 1 in 165.0g / ^{m 2,} after line mixing at a rate of 11.4 g / ^{m 2} of the following inline solution (coated amount) was coated on a support.

~ Composition of inline liquid ~
(1) Alphain 83 (manufactured by Daimei Chemical Co., Ltd.) 2.0 parts (2) Ion-exchanged water 7.8 parts (3) Himax SC-507 (Dimethylamine / Epichlorohydrin) Polycondensate, 70% solution made by Hymo Co., Ltd.) 0.2 part

The coating layer formed by the above coating was dried with a hot air dryer at 80 ° C. (wind speed of 3 to 8 m / sec) until the solid content concentration of the coating layer reached 36%. This coating layer exhibited a constant rate of drying during this period. Immediately after that, it was immersed in a solution containing a basic compound having the following composition for 3 seconds to deposit 13 g / m ² on the coating layer, and further dried at 72 ° C. for 10 minutes (drying step). An ink receiving layer was formed on one side of the support.

~ Composition of liquid containing basic compound ~
(1) Boric acid ... 0.65 parts (2) Ammonium carbonate (1st grade: manufactured by Kanto Chemical Co., Ltd.) ... 5.0 parts (3) Ion-exchanged water ... 88.35 parts (4) Polyoxyethylene lauryl ether (Surfactant) ... 6.0 parts ("Emulgen 109P" (10% aqueous solution) manufactured by Kao Corporation, HLB value 13.6)

  As described above, an ink jet recording medium having an ink receiving layer on a water-impermeable support was obtained, and the following evaluation was performed. The evaluation results are shown in Table 1.

[Evaluation]
<Cutter suitability>
With a model machine using a cutter blade assuming an actual machine, the ink jet recording medium obtained above was cut into 127 mm width × 10 mm length to evaluate cutter suitability. The ink jet recording media obtained in other examples and comparative examples were similarly evaluated and shown in the corresponding tables.
Specifically, when a plurality of inkjet recording media are continuously cut, the ink receiving layer is cracked in the vicinity of the cut surface, and cutting is performed until a problem occurs that the image is disturbed during borderless printing due to the crack. The number of sheets was examined and evaluated according to the following evaluation criteria.
~Evaluation criteria~
AA: The above problem did not occur even when 300,000 sheets or more were cut.
A: The above problem occurred when cutting 200,000 sheets or more and less than 300,000 sheets, but it was practically acceptable.
B: The above problem occurred when cutting from 100,000 sheets to less than 200,000 sheets, but was practically acceptable.
C: When the sheet was cut from 50,000 to less than 100,000, the above-described problem occurred and exceeded the practically acceptable range.
D: The above-mentioned problem occurred when cutting less than 50,000 sheets, which greatly exceeded the practical tolerance.

[Examples 2 to 9, Comparative Examples 1 to 3]
In Example 1, instead of using SC-P400, an ink jet recording medium was obtained in the same manner as in Example 1 except that it was as described in Table 1, and evaluation was performed in the same manner as in Example 1. The evaluation results are shown in Table 1. However, in Comparative Example 1, ion-exchanged water was added correspondingly instead of not performing SC-P400.

Details of the components used above will be described below.
SC-P750 (POP (9) diglyceryl ether)
SC-P1000 (POP (14) diglyceryl ether)
SC-P1200 (POP (18) diglyceryl ether)
SC-P1600 (POP (24) diglyceryl ether)
SC-E750 (POE (13) diglyceryl ether)
SC-E1500 (POE (30) diglyceryl ether)
SC-E2000 (POE (40) diglyceryl ether)

  As apparent from Table 1, the examples having the configuration of the present invention were suitable for cutter suitability.

[Example 11]
<Preparation of first coating liquid (for lower layer)>
(1) calcined kaolin, (2) ion-exchanged water, and (3) “Charol DC-902P” shown in the following composition are mixed and dispersed, and then (4) polyvinyl alcohol dissolved in the dispersion. The liquid and (5) “Superflex 650-5” were added at 30 ° C. to prepare a first coating liquid (for the lower layer).
The mass ratio between the calcined kaolin and the polyvinyl alcohol (PB ratio = (1) :( 4)) is 8.9: 1, and the pH of the first coating liquid (for the lower layer) is 4.5 and acidic. Indicated.

-Composition of first coating liquid (for lower layer)-
(1) Calcined kaolin (Kaokaru, manufactured by Shiraishi Calcium Co., Ltd.) 8.9 parts (2) Ion exchange water 15.0 parts (3) “Charol DC-902P” (51.5% aqueous solution) 78 parts (dispersant, nitrogen-containing organic cationic polymer, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
(4) Polyvinyl alcohol (water-soluble resin) solution ... 20.0 parts-Composition of solution-
・ JM33 (polyvinyl alcohol (PVA); degree of saponification 95.5%, degree of polymerization 3300, manufactured by Nippon Acetate / Poval Co., Ltd.) ... 1.0 part ・ HPC-SSL (water-soluble cellulose, manufactured by Nippon Soda Co., Ltd.) 0.02 parts ・ Ion-exchanged water 17.0 parts SC-P750 (Sakamoto Chemical Co., Ltd.) 1.78 parts Emulgen 109P (surfactant, manufactured by Kao Corporation) 2 parts (5) Cation-modified polyurethane (Superflex 650-5 (25% liquid), manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 1.8 parts

<Preparation of second coating liquid (for upper layer)>
(1) Gas phase method silica fine particles, (2) ion-exchanged water, (3) “Charol DC-902P”, and (4) “ZA-30” shown in the following composition are mixed to obtain a liquid. After dispersion using a liquid collision type disperser (Ultimizer, manufactured by Sugino Machine Co., Ltd.), the obtained dispersion was heated to 45 ° C. and held for 20 hours. Thereafter, (5) boric acid, (6) polyvinyl alcohol solution, and (7) cation-modified polyurethane were added to the dispersion at 30 ° C. to prepare a second coating solution (for the upper layer).
The mass ratio between the silica fine particles and the water-soluble resin (PB ratio = (1) :( 6)) is 4.9: 1, and the pH of the second coating liquid (for the upper layer) is 3.4 and acidic. showed that.

-Composition of second coating liquid (for upper layer)-
(1) Vapor phase silica fine particles (inorganic fine particles) 8.9 parts (AEROSIL300SF75, manufactured by Nippon Aerosil Co., Ltd.)
(2) Ion-exchanged water: 47.3 parts (3) “Charol DC-902P” (51.5% aqueous solution) 0.78 parts (dispersant, nitrogen-containing organic cationic polymer, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) )
(4) "ZA-30": 0.48 parts (Daiichi Rare Element Chemical Co., Ltd., zirconyl acetate)
(5) Boric acid (7.5% aqueous solution) ... 4.38 parts (6) Polyvinyl alcohol (water-soluble resin) solution ... 26.0 parts

~ Composition of solution ~
・ JM33 (polyvinyl alcohol (PVA); degree of saponification 95.5%, degree of polymerization 3300, manufactured by Nippon Acetate / Poval) 1.81 parts ・ HPC-SSL (water-soluble cellulose, manufactured by Nippon Soda Co., Ltd.) 0.08 parts ・ Ion-exchanged water ... 22.96 parts ・ Diethylene glycol monobutyl ether (Buticenol 20P) 0.55 parts (Kyowa Hakko Chemical Co., Ltd.)
Emulgen 109P (surfactant, manufactured by Kao Corporation) 0.6 parts (7) Cation-modified polyurethane (Superflex 650-5 (25% solution), manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 1.8 Part

<Formation of ink receiving layer>
After performing corona discharge treatment on one surface of the water-impermeable support obtained above, the first coating liquid (for the lower layer) and the second coating are applied to the one surface as follows. The liquid (for upper layer) was simultaneously applied by an extrusion die coater to form a coating layer.
Specifically, in the simultaneous multi-layer coating, the first coating solution (for the lower layer) is applied inline at a coating amount of 42.8 g / m ² and the following inline solution is applied at a rate of 5.7 g / m ² (coating amount). was applied to the lower layer after mixing, coating a second coating liquid (upper layer) in 82.5 g / ^{m 2,} the upper layer was in-line mixed at a rate of 5.7 g / ^{m 2} of the following inline liquid (coating amount) (The layer structure is second coating liquid (for upper layer) / first coating liquid (for lower layer) / support).

~ Composition of inline liquid ~
(1) Alphain 83 (manufactured by Daimei Chemical Co., Ltd.) 2.0 parts (2) Ion-exchanged water 7.8 parts (3) Himax SC-507 (Dimethylamine / Epichlorohydrin) Polycondensate (manufactured by Hymo Co., Ltd.) ・ ・ ・ 0.2 parts

The coating layer formed by the simultaneous multilayer coating was dried with a hot air dryer at 80 ° C. (wind speed 3 to 8 m / sec) until the solid content concentration of the coating layer reached 36%. This coating layer exhibited a constant rate of drying during this period. Immediately after that, it was immersed in a solution containing a basic compound having the following composition for 3 seconds to deposit 13 g / m ² on the coating layer, and further dried at 72 ° C. for 10 minutes (drying step). An ink receiving layer was formed on one side of the support.

~ Composition of liquid containing basic compound ~
(1) Boric acid ... 0.65 parts (2) Ammonium carbonate (1st grade: manufactured by Kanto Chemical Co., Ltd.) ... 5.0 parts (3) Ion-exchanged water ... 88.35 parts (4) Polyoxyethylene lauryl ether (Surfactant) ... 6.0 parts ("Emulgen 109P" (10% aqueous solution) manufactured by Kao Corporation, HLB value 13.6)

[Examples 12 to 16, Comparative Examples 11 to 13]
In Example 11, instead of using SC-P750, an ink jet recording medium was obtained in the same manner as in Example 11 except that the conditions described in Table 2 were used. However, in Comparative Example 11, ion-exchanged water was added correspondingly instead of not using SC-P750.

[Example 17]
Inkjet recording was carried out in the same manner as in Example 11 except that the ion-exchanged water and SC-P400 in the composition of the polyvinyl alcohol (water-soluble resin) solution in Example 11 were changed as described below and shown in Table 2. A medium was obtained.
-Ion-exchanged water ... 16.11 parts-SC-P1200 (Sakamoto Chemical Co., Ltd.) ... 2.67 parts [Example 18]
Inkjet recording was carried out in the same manner as in Example 11 except that the ion-exchanged water and SC-P400 in the composition of the polyvinyl alcohol (water-soluble resin) solution in Example 11 were changed as described below and shown in Table 2. A medium was obtained.
・ Ion-exchanged water: 17.88 parts ・ SC-P1200 (Sakamoto Chemical Co., Ltd.): 0.90 parts

[Examples 19 and 20]
In Example 18, an ink jet recording medium was obtained in the same manner as in Example 18 except that SC-P1200 was used instead of using SC-P1200.

  As is clear from Table 2, the examples having the configuration of the present invention were suitable for cutter suitability.

[Example 21] (addition of lubricant to intermediate layer)
<Preparation of third coating liquid (for intermediate layer)>
A polyvinyl alcohol solution shown in the composition below was dissolved at 90 ° C. to prepare a third coating solution (for the intermediate layer).

-Composition of third coating liquid (for intermediate layer)-
-PVA235 (polyvinyl alcohol (PVA); degree of saponification 88%, degree of polymerization 3500, manufactured by Kuraray Co., Ltd.) ... 5 parts-SC-P400 (manufactured by Sakamoto Chemical Co., Ltd.) ... 5 parts-Ion exchange water ... 89.8 parts ・ Emulgen 109P (surfactant, manufactured by Kao Corporation) 0.2 parts

<Formation of intermediate layer>
After the corona discharge treatment is performed on one surface of the water-impermeable support obtained above, a third coating solution (for the intermediate layer) is applied to the one surface as follows. The intermediate layer was formed by coating with a coater.
Specifically, a third coating solution (for the intermediate layer) was applied at a coating amount of 40 g / m ² .

<Formation of ink receiving layer>
On the intermediate layer obtained above, the second coating solution (for the upper layer) was applied with an extrusion die coater to form a coating layer.
Specifically, the second coating liquid (upper layer) in 165.0g / ^{m 2,} was coated in-line liquid in the upper layer was in-line mixed at a rate of 11.4 g / ^{m 2} (coated amount).

The coating layer formed by the above coating was dried with a hot air dryer at 80 ° C. (wind speed of 3 to 8 m / sec) until the solid content concentration of the coating layer reached 36%. This coating layer exhibited a constant rate of drying during this period. Immediately after that, it was immersed in a liquid containing a basic compound for 3 seconds to deposit 13 g / m ² on the coating layer, and further dried at 72 ° C. for 10 minutes (drying step). An ink receiving layer was formed on one side.

[Examples 22-30, Comparative Examples 21-23]
An ink jet recording medium was obtained in the same manner as in Example 21 except that Example 21 was changed as described in Table 3 instead of SC-P400. However, in Comparative Example 21, ion-exchanged water was added correspondingly instead of not performing SC-P400.

  As is apparent from Table 3, the examples having the configuration of the present invention were suitable for cutter suitability.

[Example 31] (2 layers of receiving layer, lubricant added only to the lower layer)
<Formation of ink receiving layer>
After the corona discharge treatment is performed on one surface of the water-impermeable support obtained above, the receiving layer coating solution 1 (for the lower layer) and the second coating are applied to the one surface as follows. The liquid (for upper layer) was simultaneously applied by an extrusion die coater to form a coating layer.
Specifically, in the simultaneous multilayer coating, inline-receiving layer coating liquid 1 (for lower layer) at a coverage of 82.5 g / ^{m 2,} rate of 5.7 g / ^{m 2} of the following inline liquid (coating amount) After mixing, it was applied to the lower layer, the second coating solution (for the upper layer) was mixed in-line at a rate (application amount) of 82.5 g / m ² and the in-line solution was 5.7 g / m ² , and then applied to the support. (The layer structure is the second coating solution (for upper layer) / receiving layer coating solution 1 (for lower layer) / support).
The coating layer formed by the simultaneous multilayer coating was dried with a hot air dryer at 80 ° C. (wind speed 3 to 8 m / sec) until the solid content concentration of the coating layer reached 36%. This coating layer exhibited a constant rate of drying during this period. Immediately after that, it was immersed in a liquid containing a basic compound for 3 seconds to deposit 13 g / m ² on the coating layer, and further dried at 72 ° C. for 10 minutes (drying step). An ink receiving layer was formed on one side.

[Examples 32 to 40, Comparative Examples 31 to 33]
An ink jet recording medium was obtained in the same manner as in Example 31 except that Example 31 was changed as described in Table 4 instead of SC-P400. However, in Comparative Example 31, ion-exchanged water was added correspondingly instead of adding SC-P400.

  As apparent from Table 4, the examples having the configuration of the present invention were suitable for cutter suitability.

[Examples 41 to 42]
In Example 31, an ink receiving layer (upper and lower layers) was formed on one surface of the non-permeable support in the same manner as in Example 31, and the other surface was also treated in the same manner as in Example 31. Thus, an ink receiving layer (upper and lower layers) was formed to obtain a double-sided ink jet recording medium having two ink receiving layers.
The performances of the double-sided products of Examples 41 and 42 were all the same as those of the single-sided products.

  In addition, you may provide the barrier layer which has an aqueous binder as a main component between an aqueous | water-based lubricant addition layer and a receiving layer on a support body.

Claims (6)

An ink jet recording medium comprising an aqueous lubricant having an ink receiving layer containing inorganic fine particles and a water-soluble resin on at least one surface of a support and having an average molecular weight of 350 or more. The inkjet recording medium according to claim 1, wherein the aqueous lubricant is a diglycerin derivative. The inkjet recording medium according to claim 1 or 2, wherein the content of the aqueous lubricant is 5 to 20% by mass with respect to the inorganic fine particles. The inkjet recording medium according to any one of claims 1 to 3, wherein the inorganic fine particles are vapor phase silica. The inkjet recording medium according to any one of claims 1 to 4, wherein the aqueous lubricant is contained in an intermediate layer. The ink jet recording medium according to claim 1, wherein the ink receiving layer is provided on both sides of the support.