JP2006168161A - Substrate for image recording material, and image recording material and medium for inkjet recording which use the substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate for an image recording material which is free from the gloss unevenness and glare of a surface and excellent in sharpness, and the image recording material and a medium for inkjet recording which use the substrate. <P>SOLUTION: The substrate for the image recording material has a base coated with a polyolefin resin on both sides. The base is constituted of coated paper or a white film, and the surface of the polyolefin resin coating the base on the side whereon an image receiving layer is provided is constituted of an embossed roughened surface. The image recording material and the medium for inkjet recording which use the substrate are disclosed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image recording material support, an image recording material using the image recording material support, and an ink jet recording medium, and more particularly to an ink jet recording medium, an electrophotographic image receiving material, a thermosensitive color recording material, and a sublimation transfer image receiving material. The present invention relates to an image recording material support suitably used for a thermal transfer image receiving material and a silver salt photographic light-sensitive material support, an image recording material using the image recording material support, and an ink jet recording medium.

  Conventionally, as a support for image materials such as silver halide photographic printing paper, ink jet recording medium, and thermal transfer recording image receiving sheet, a resin-coated support whose base paper surface is coated with a resin capable of forming a film is well known. ing.

  In particular, the ink jet recording system has advantages such as easy multi-coloring, relatively high recording speed, and large plate recording. On the other hand, clogging and maintenance of nozzles, which has been a problem in the past, have been improved from both the ink and device sides, and are now widely used in various fields such as various printers, facsimiles, and computer terminals. It is rapidly becoming popular.

  In recent years, the demand for so-called photographic-like high-quality recording media has increased along with the increase in resolution of inkjet printers in inkjet recording systems, and inkjet paper has a high-class feel similar to conventional silver salt photography. Is desired.

  On the other hand, a resin-coated paper-type support having improved apparent glossiness and smoothness has been proposed, and further improvements are desired (for example, see Patent Document 1).

Moreover, in order to avoid a state where reflected light is too strong to be viewed, image materials are generally formed with irregularities with a height of the order of 1 μm on the surface, but the surface is appropriately roughened. When ink jet recording is performed on the obtained recording medium, there is a problem that the gloss changes to an image and the glossiness tends to be uneven. On the other hand, an ink jet recording medium in which the surface roughness and glossiness of the surface of the ink absorbing layer is defined using paper (base paper) coated on both sides with a polyolefin resin as a support has been proposed. The glare is not completely eliminated (see, for example, Patent Document 2).
JP 2001-301098 A JP 2000-355160 A

An object of the present invention is to solve the conventional problems.
That is, an object of the present invention is to provide a support for an image recording material which has no surface gloss unevenness and no glare and is excellent in sharpness, and an image recording material and an ink jet recording medium using the support. .

As a result of intensive studies, the present inventors have found that the following present invention solves the above-mentioned problems and have completed the present invention. That is, the present invention
<1> A support for an image recording material in which both surfaces of a substrate are coated with a polyolefin resin,
The support for an image recording material, characterized in that the substrate is made of coated paper or an opaque film, and the surface of the polyolefin resin that covers the substrate on the side where the image receiving layer is provided is a rough surface that has been subjected to a die-molding process. It is.

<2> The Beck smoothness (JIS P 8119) of the surface on the side where the image receiving layer of the base material is provided is 600 seconds or more, and the surface of the polyolefin resin covering the base material on the side where the image receiving layer is provided The support for an image recording material according to <1>, wherein the Beck smoothness (JIS P 8119) is 20 to 500 seconds.

<3> The center plane average roughness (SRa value) of the surface of the substrate on the side where the image receiving layer is provided is less than 0.75 μm when measured under conditions of a cutoff of 1 to 3 mm. <1> or the support for an image recording material according to <2>.

<4> It is used as any one support selected from electrophotographic image receiving materials, heat-sensitive color developing recording materials, sublimation transfer image receiving materials, thermal transfer image receiving materials, silver salt photographic light-sensitive materials, and ink jet recording media. <1> to the support for an image recording material according to any one of <3>.
<5> The image recording material support according to <4>, which is used as a support for an inkjet recording medium.

<6> An image recording material having a support and at least one image-receiving layer on the support, wherein the image recording material support described in <4> is used as the support. Recording material.
<7> An inkjet recording medium having a support and at least one ink image-receiving layer on the support, wherein the support for an image recording material according to <5> is used as the support. This is an inkjet recording medium.

  According to the present invention, it is possible to provide a support for an image recording material which is free from surface unevenness and glare and has excellent sharpness, and an image recording material and an ink jet recording medium using the support.

<Support for image recording material>
The support for an image recording material of the present invention is a support for an image recording material in which both surfaces of a substrate are coated with a polyolefin resin, and the substrate is made of coated paper or an opaque film, and is provided with an image receiving layer. The surface of the polyolefin resin coated with the substrate is a rough surface that has been subjected to a die-molding process.

(Base material)
The base material in this invention consists of a coated paper or an opaque film. The coated paper and the opaque film generally have a Beck smoothness (JIS P 8119), which will be described later, of 600 seconds or more, and a center plane average roughness (SRa value, when measured under conditions of a cutoff of 1 to 3 mm. Hereinafter, it may be referred to as “central surface average roughness in the present invention”) is less than 0.75 μm. In this way, by using a base material that is smooth and has a small roughness (at least on the side on which the image receiving layer is provided), there is an effect that there is no surface gloss unevenness or glare and excellent sharpness. On the other hand, paper base materials other than coated paper, such as base paper, have a Beck smoothness of less than 600 seconds and a center surface average roughness in the present invention of more than 0.75 μm. There is no unevenness or glare, and the effect of excellent sharpness cannot be obtained. Moreover, when a transparent film is used as a base material, glare will generate | occur | produce.

  The coated paper means a paper provided with a layer containing a pigment and an adhesive, and the pigment and the adhesive, as well as the finely coated paper, lightweight coated paper, coated paper, and art paper, which are commonly called names. And a cast coated paper that directly presses a heated cast drum.

As the base paper, wood pulp is used as a main raw material, and paper is made using synthetic pulp such as polypropylene or synthetic fibers such as nylon or polyester in addition to wood pulp as necessary. 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 or more and 70% by mass or less.

  The pulp is preferably a chemical pulp (sulfate pulp or sulfite pulp) with few impurities, and a pulp having a whiteness improved by bleaching is also useful.

  In the base paper, sizing agents such as higher fatty acids and alkyl ketene dimers, white pigments such as calcium carbonate, talc and titanium oxide, paper strength enhancing agents such as starch, polyacrylamide and polyvinyl alcohol, fluorescent whitening agents, polyethylene glycols A water retaining agent such as a dispersant, a softening agent such as a quaternary ammonium, and the like can be appropriately added.

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

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

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

Examples of the pigment include kaolin, (calcined) clay, heavy calcium carbonate, light calcium carbonate, satin white, titanium dioxide, aluminum hydroxide, silica, plastic pigment, and the like, among which kaolin and calcium carbonate. preferable.
Examples of the adhesive include starch, modified starch, casein, polyvinyl alcohol, latex such as SBR and MBR, and barium sulfate.

  The layer containing the pigment and the adhesive may contain other auxiliary agents. Examples of the other auxiliary agents include dispersants, antifoaming agents, lubricants, water resistance agents, viscosity improvers, water retention agents, Examples include preservatives and dyes.

The layer containing the pigment and the adhesive can be formed by, for example, applying a solution prepared by dissolving and dispersing in an aqueous solvent to at least one surface of a base paper by a known application method.
Examples of the known coating method include a roll coater, a gravure coater, a die coater, a curtain coater, a spray coater, a blade coater, a rod coater, an impregnation coater, a cast coater, and an air knife coater.

  The opaque film means a plastic film made opaque by containing a color pigment. Among the colored pigments, a white pigment is particularly preferable. Examples of the resin that is the main component of the plastic film include polyesters such as polyethylene terephthalate (PET); polyolefins such as polyethylene and polypropylene; cellulose esters such as nitrocellulose, cellulose acetate, and cellulose acetate butyrate; and polysulfone and polyphenylene. Examples thereof include oxide, polyimide, polycarbonate, and polyamide.

  On the other hand, examples of the white pigment include titanium dioxide, barium sulfate, calcium carbonate, and zinc oxide. Moreover, as content in the opaque film of a white pigment, 2-50 mass% is preferable and 5-20 mass% is more preferable. Moreover, it is preferable that the Hunter whiteness is 85% or more and the Hunter opacity is 90% or more.

  A color pigment, a fluorescent brightening agent, an antioxidant, and the like may be further added to the opaque film. Moreover, you may perform a surface calendar process etc. to the obtained opaque film.

  In the present invention, the Beck smoothness (JIS P 8119) of the surface on the side of the substrate on which the image receiving layer is provided is preferably 600 seconds or more, more preferably 800 seconds or more, and 1000 seconds or more. More preferably. When the Beck smoothness of the surface on the side of the substrate on which the image receiving layer is provided is 600 seconds or more, the effect that the surface has no gloss unevenness or glare and is excellent in sharpness becomes more remarkable.

  Moreover, in this invention, it is preferable that the center plane average roughness (SRa) when measured on the conditions of the cut-off 1-3 mm of the surface at the side which provides the image receiving layer of the said base material is less than 0.75 micrometer. More preferably, it is less than 0.5 μm, and still more preferably less than 0.3 μm. When the average roughness of the center plane in the present invention is less than 0.75 μm, the effect that there is no surface gloss unevenness or glare and the sharpness is excellent becomes more remarkable.

The method of measuring the center plane average roughness (SRa value) under conditions of a cutoff of 1 to 3 mm is as follows.
-Equipment used Kuroda Seiko Co., Ltd. Surface shape measuring device Nano Metro 110F
Measurement and analysis conditions Scanning direction: MD direction of sample Measurement length: X direction 50 mm, Y direction 40 mm
Measurement pitch: 0.15 mm in the X direction, 0.2 mm in the Y direction
Scanning speed: 30mm / sec
Bandpass filter: 1-3mm
Filter tilt: -12 dB / Oct
Effective range of filter tilt: Up to 1/2 wavelength (3 mm here) on the short wavelength side
Long wavelength side up to double wavelength (14mm here)

(Polyolefin resin layer)
In the support for image recording material of the present invention, both surfaces of the substrate are coated with a polyolefin resin. The polyolefin resin layer (polyolefin resin layer) covering both sides of this substrate is
When the image-receiving layer is provided, it is provided so that the surface reflection image is sharply formed. The image-receiving layer contains at least a polyolefin resin, and may contain other components as necessary.

  Examples of the polyolefin resin include homopolymers such as polyethylene, polypropylene, polybutene, and polypentene; copolymers composed of two or more α-olefins such as an ethylene-butylene copolymer; and mixtures thereof. In particular, a polyethylene resin is particularly preferable from the viewpoints of melt extrusion coating properties and adhesiveness to the base paper.

Examples of the polyethylene resin include low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, copolymers of ethylene and α-olefin such as propylene, butylene, carboxy-modified polyethylene, and the like. A mixture of these may be used, and various densities, melt flow rates (hereinafter simply abbreviated as “MFR”), molecular weight, and molecular weight distribution can be used. Usually, the density is 0.90 to 0.97 g. In the range of / cm ³ and MFR of 0.1 to 50 g / 10 min, and preferably in the range of MFR of 0.3 to 40 g / 10 min, alone or in combination.

  The layer thickness of the polyolefin resin layer is useful from 4 to 100 μm, preferably from 6 to 50 μm, particularly preferably from 9 to 35 μm.

  The polyolefin resin preferably contains titanium dioxide for the purpose of increasing image resolution. Examples of the titanium dioxide include various types of titanium dioxide such as those based on the sulfuric acid method, those based on the chlorine method, rutile type, anatase type, surface treated with a hydrous metal oxide, and surface treated with an organic compound. It is done.

  As a method of coating the surface of the substrate with a polyolefin resin (preferably a polyethylene tree), a polyolefin containing a resin or an additive on a traveling base paper in terms of flatness and processability of a tidying process described later. A method of coating the resin composition by a so-called melt extrusion coating method in which a resin composition is cast from a slit die into a film using a melt extruder is preferable.

  Various additives can be contained in the polyolefin resin layer. Examples of the additive include titanium dioxide, white pigments such as zinc oxide, talc, and calcium carbonate; dispersants for titanium dioxide pigments and other pigments; fatty acids such as stearamide and arachidic acid amide as mold release agents. Fatty acid metal salts such as amide, zinc stearate, calcium stearate, aluminum stearate, magnesium stearate, zinc palmitate, zinc myristate, calcium palmitate; hindered phenols described in JP-A-1-105245; Hindered amine, phosphorus, sulfur and other antioxidants; cobalt blue, ultramarine blue, ceria blue, phthalocyanine blue and other blue pigments and dyes; cobalt violet, fast violet, manganese violet and other magenta pigments and dyes; Special fairness 4 Described in 2175 JP, quinacridone red pigments; described in JP-A-2-254440, fluorescent whitening agents, ultraviolet absorbers, etc., and may be contained in combination as appropriate.

  The additive is preferably used in the polyolefin resin composition for forming the polyolefin resin layer or contained as a master batch or compound of a resin prepared separately.

(Molding process)
The support for an image recording material of the present invention is characterized in that at least the surface on the side on which the image receiving layer is provided of the base material coated on both sides with a polyolefin resin is subjected to a die forming process to be roughened.
By using a molding process as the roughening means, an effect of reducing uneven glossiness on the image surface can be obtained.
Immediately after casting and coating the polyolefin resin in the form of a film, the molding process is performed by pressing a cooling roll having various irregularities on the surface on which the image receiving layer is provided and cooling the polyolefin resin while cooling. Examples of the method include performing various types of molding on the surface of the layer.

As temperature of the cooling roll in the case of the said shaping | molding process, 5-30 degreeC is preferable and 10-20 degreeC is more preferable.
Further, by adjusting the surface roughness of the cooling roll, the Beck smoothness of the surface of the polyolefin resin layer on the side where at least the image receiving layer described later is provided can be easily adjusted to a preferable value of 20 to 500 seconds. That is, it is preferable that the height of the unevenness of the cooling roll is a height that makes the Beck smoothness of the surface of the polyolefin resin layer 20 to 500 seconds.

The support for an image recording material of the present invention is a support for an image recording material having no sharp glossiness and no glare on the surface, and having excellent sharpness by molding the polyolefin resin layer on the side on which the image receiving layer is provided to form a rough surface. Become a body.
The Beck smoothness (JIS P 8119) of the surface of the polyolefin resin layer on the side where the image-receiving layer subjected to the above-mentioned mold processing is provided is preferably 20 to 500 seconds, more preferably 30 to 400 seconds, and more preferably 50 to 300. More preferably, it is seconds. When the Beck smoothness of the surface of the polyolefin resin layer on the side on which the image receiving layer is provided is 20 to 500 seconds, the effect that there is no surface unevenness of gloss and no glare and the sharpness is excellent becomes more remarkable.

<Image recording material>
The support for an image recording material of the present invention is any one support selected from an electrophotographic image receiving material, a heat-sensitive color developing recording material, a sublimation transfer image receiving material, a thermal transfer image receiving material, a silver salt photographic photosensitive material, and an ink jet recording medium. It is preferably used as a support, and particularly preferably used as a support for an inkjet recording medium. Hereinafter, each image recording material will be described.

[Image receiving material for electrophotography]
The electrophotographic image-receiving material has a support for an image recording material of the present invention, and a toner image-receiving layer on a polyolefin resin layer on which the support is molded, and other layers appropriately selected as necessary. For example, surface protection layer, intermediate layer, undercoat layer, cushion layer, charge control (prevention) layer, reflection layer, tint preparation layer, storage stability improvement layer, adhesion prevention layer, anti-curl layer, smoothing layer, etc. It becomes. Each of these layers may have a single layer structure or a laminated structure.

[Silver photographic material]
The silver salt photographic light-sensitive material has, for example, a structure in which an image forming layer that develops color at least on YMC is provided on the mold-processed polyolefin resin layer of the image recording support of the present invention, and is subjected to printing exposure. Examples of the silver halide photographic system include a method in which color development, bleach-fixing, washing with water and drying are performed by passing the silver halide photographic sheet while immersing it in a plurality of processing tanks.

[Thermal transfer image receiving material]
The thermal transfer material has, for example, a structure in which at least a thermochromic layer is provided on a mold-processed polyolefin resin layer of the image recording support of the present invention, and heating by a thermal head and fixing by ultraviolet rays are repeated. And a thermosensitive color recording material used in a thermoautochrome method (TA method) for forming an image.

[Thermosensitive color recording material]
The heat-sensitive color recording material has, for example, a structure in which at least a heat-meltable ink layer as an image forming layer is provided on the mold-processed polyolefin resin layer of the image recording support of the present invention. Examples thereof include a system in which ink is heated and transferred from a heat-meltable ink layer to a heat-sensitive transfer recording image-receiving sheet.

[Sublimation transfer image receiving material]
The sublimation transfer image-receiving material has a configuration in which an ink layer containing at least a heat-diffusible dye (sublimation dye) is provided on the mold-processed polyolefin resin layer of the image recording support of the present invention. And a sublimation transfer method in which a thermal diffusible dye is transferred from an ink layer onto a thermal transfer recording image receiving sheet by heating with a thermal head.

<Inkjet recording medium>
As described above, the image recording support of the present invention is particularly preferably used as a support for inkjet recording media. Hereinafter, an ink jet recording medium using the image recording support of the present invention will be described.
The ink-jet recording medium of the present invention has at least an ink image-receiving layer on the polyolefin resin layer subjected to the molding process of the image recording support of the present invention described above.
The ink jet recording medium of the present invention will be described below.

(Ink receiving layer)
The ink image-receiving layer preferably includes at least an inorganic pigment fine particle having an average primary particle size of 20 nm or less, a water-soluble resin, a mordant, and a cross-linking agent. May be included. The ink image-receiving layer is preferably formed on the substrate by the WOW method as described later.

(Inorganic pigment fine particles)
The ink image-receiving layer preferably contains anhydrous pigment fine particles having an average primary particle size of 20 nm or less.
Examples of the inorganic pigment 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. Can be mentioned. Among these, silica fine particles are particularly preferable.

  Since the silica fine particles have a particularly large specific surface area, the ink absorbency and retention efficiency are high, and since the refractive index is low, if the dispersion is carried out to an appropriate particle size, the receiving layer can be transparent and high. The color density and good color developability are obtained. It is important that the receiving layer is transparent from the viewpoint of obtaining a high color density and good color developability not only for applications that require transparency, such as OHP, but also for recording paper such as photo glossy paper. is there.

  The average primary particle diameter of the inorganic pigment fine particles is more preferably 10 nm or less, and most preferably 3 to 10 nm.

  The silica fine particles have a cynoral group on the surface thereof, and the particles are likely to adhere to each other by hydrogen bonding due to the silanol group, so that a structure having a large porosity is formed when the average primary particle diameter is 10 nm or less as described above. Ink absorption characteristics can be effectively improved.

Silica fine particles are roughly classified into wet method particles and dry method particles according to the production method.
In the wet method, a method is mainly used in which active silica is produced by acid decomposition of silicate, and this is appropriately polymerized and coagulated and precipitated to obtain hydrous silica. On the other hand, the dry 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 arc in an electric furnace and oxidized with air ( The method of obtaining anhydrous silica by the arc method is the mainstream.

The hydrous silica and anhydrous silica obtained by these methods are different in the density of silanol groups on the surface, the presence or absence of vacancies, etc., and show different properties, respectively, especially in the case of anhydrous silica (anhydrous silicic acid). It is particularly preferable because a three-dimensional structure having a high porosity is easily formed. 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 high at 5 to 8 / nm ² , and the silica fine particles tend to aggregate closely (aggregate). In this case, since the density of silanol groups on the surface of the fine particles is as small as ² to 3 / nm ² , sparse soft aggregation (flocculate) is obtained, and as a result, it is estimated that the structure has a high porosity. .
Accordingly, in the present invention, it is preferable to use silica (silica fine particles) having a silanol group density of 2 to 3 / nm ² on the surface of the fine particles.

  From the viewpoint of transparency, the type of resin to be combined with the silica fine particles is important. When anhydrous silica is used, the water-soluble resin is preferably polyvinyl alcohol (PVA), and particularly, a saponification degree of 70 to 99%. PVA is more preferable, and PVA having a saponification degree of 70 to 90% is most preferable.

The PVA has a hydroxyl group in its structural unit, and this hydroxyl group and a silanol group on the surface of the silica fine particle form a hydrogen bond, thereby making it easy to form a three-dimensional network structure in which the secondary particle of the silica fine particle is a chain unit. . It is considered that an ink image-receiving layer having a porous structure with a high porosity can be formed by forming the three-dimensional network structure.
The porous ink image-receiving layer thus obtained can rapidly absorb ink by capillary action in ink jet recording and form a spot with good roundness without ink bleeding.

The content ratio of the inorganic pigment fine particles (preferably silica fine particles; i) to the water-soluble resin (p) [PB ratio (i: p), the mass of the inorganic pigment fine particles relative to 1 part by mass of the water-soluble resin] The film structure is also greatly affected. That is, as the PB ratio increases, the porosity, pore volume, and surface area (per unit mass) increase.
Specifically, the PB ratio (i: p) is preferably 1.5: 1 to 10: 1. When the PB ratio exceeds 10: 1, that is, when the PB ratio is too large, the film strength may be reduced, and cracking may occur during drying. The ratio is less than 1.5: 1, that is, the PB ratio is too small. As a result, the voids are likely to be blocked by the resin, and as a result, the void ratio may decrease and the ink absorbability may decrease.

Since stress may be applied to the recording paper when passing through the conveyance system of the ink jet printer, the ink image receiving layer needs to have sufficient film strength. Further, when cutting into a sheet shape, the ink image-receiving layer needs to have sufficient film strength to prevent the ink image-receiving layer from being cracked or peeled off.
In this case, the PB ratio is preferably 5: 1 or less, and preferably 2: 1 or more from the viewpoint of securing high-speed ink absorbability with an inkjet printer.

For example, a coating solution in which anhydrous silica fine particles having an average primary particle size of 20 nm or less and a water-soluble resin are completely dispersed in an aqueous solution at a PB ratio of 2: 1 to 5: 1 is applied on a substrate, and the coating layer is dried. In this case, 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% or more, the pore specific volume is 0.5 ml / g or more, and the specific surface area is A light-transmitting porous film having a size of 100 m ² / g or more can be easily formed.

(Water-soluble resin)
Examples of the water-soluble resin include resins having a hydroxyl group as a hydrophilic structural unit, such as polyvinyl alcohol (PVA), cation-modified polyvinyl alcohol, anion-modified polyvinyl alcohol, silanol-modified polyvinyl alcohol, polyvinyl acetal, and cellulose resin [ Methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC), etc.], chitins, chitosans, starch; polyethylene oxide (PEO) and polypropylene oxide (PPO) which are resins having an ether bond , Polyethylene glycol (PEG), polyvinyl ether (PVE); polyacrylamide (PAAM) which is a resin having an amide group or an amide bond, poly Nirupiroridon (PVP) and the like.
In addition, polyacrylates, maleic resins, alginates, and gelatins having a carboxyl group as a dissociable group can be exemplified.
Among the above, polyvinyl alcohols are particularly preferable.

As content of the said water-soluble resin, 9-40 mass% is preferable with respect to the total solid content mass of an ink image receiving layer, and 16-33 mass% is more preferable.
When the content is less than 9% by mass, the film strength is lowered, and cracking is likely to occur during drying. When the content exceeds 40% by mass, the voids are easily blocked by the resin. May decrease and the ink absorbency may decrease.

  The inorganic pigment fine particles and the water-soluble resin, which mainly constitute the ink image-receiving layer, may each be a single material or a mixed system of a plurality of materials.

(mordant)
As the mordant, a cationic polymer (cationic mordant) can be used. When the mordant is present in the ink image-receiving layer, it interacts with a liquid ink having an anionic dye as a colorant to stabilize the colorant. Water resistance and bleeding over time can be improved.

  However, when this is added directly to the coating liquid for forming the ink image-receiving layer, there is a possibility that aggregation may occur with inorganic pigment fine particles having an anionic charge such as silica. If a method of preparing and applying as a solution is used, there is no need to worry about aggregation of inorganic pigment fine particles. Therefore, in the present invention, it is preferably contained in a later-described crosslinking agent solution.

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

  Examples of the monomer (mordanting monomer) include trimethyl-p-vinylbenzylammonium chloride, trimethyl-m-vinylbenzylammonium chloride, triethyl-p-vinylbenzylammonium chloride, triethyl-m-vinylbenzylammonium chloride, N , N-dimethyl-N-ethyl-Np-vinylbenzylammonium chloride, N, N-diethyl-N-methyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-Nn-propyl-N -P-vinylbenzylammonium chloride, N, N-dimethyl-Nn-octyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N-benzyl-Np-vinylbenzylammonium chloride, N, N-die Ru-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.

  Specifically, for example, 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) ethyl Ammonium chloride, trimethyl-2- (acryloylamino) ethylammonium chloride, triethyl-2- ( Acryloylamino) ethylammonium chloride, trimethyl-3- (methacryloylamino) propylammonium chloride, triethyl-3- (methacryloylamino) propylammonium chloride, trimethyl-3- (acryloylamino) propylammonium chloride, triethyl-3- (acryloyl) Amino) 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.

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

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

  Further, as a polymer mordant, polydiallyldimethylammonium chloride, polymethacryloyloxyethyl-β-hydroxyethyldimethylammonium chloride, polyethylenimine, polyallylamine, polyallylamine hydrochloride, polyamide-polyamine resin, cationized starch, dicyandiamide formalin condensate Dimethyl-2-hydroxypropylammonium salt polymer, polyamidine, polyvinylamine and the like can also be mentioned as preferable examples.

  The molecular weight of the polymer mordant is preferably 1000 to 200000. When the molecular weight is less than 1000, the water resistance tends to be insufficient, and when it exceeds 200,000, the viscosity becomes too high and handling suitability may be lowered.

  As the cationic non-polymer mordant, for example, water-soluble metal salts such as aluminum sulfate, aluminum chloride, polyaluminum chloride, and magnesium chloride are preferable.

(Crosslinking agent)
The ink image-receiving layer of the ink jet recording medium of the present invention is further provided with a solution (crosslinking agent solution) containing at least a crosslinking agent and a mordant on the coating layer (porous layer) containing inorganic pigment fine particles and a water-soluble resin. The water-soluble resin is preferably cured by a crosslinking reaction with a crosslinking agent.

  The application of the crosslinking agent solution is performed simultaneously with the application of the coating liquid for forming the porous ink image-receiving layer (ink image-receiving layer coating liquid) or by applying the ink image-receiving layer coating liquid. It is preferably done before the layer becomes decelerated. By this operation, it is possible to effectively prevent the occurrence of cracks that occur during the drying of the coating layer. That is, the cross-linking agent solution penetrates into the coating layer at the same time as the coating solution is applied or before the coating layer exhibits a reduced rate of drying, and reacts quickly with the water-soluble resin in the coating layer, By gelling (curing) the water-soluble resin, the film strength of the coating layer is immediately and greatly improved.

As the cross-linking agent capable of cross-linking the water-soluble resin, a suitable one may be selected as appropriate in relation to the water-soluble resin used in the ink image-receiving layer. Among them, a boron compound is preferable because the cross-linking reaction is rapid. For example, borax, boric acid, borates (for example, orthoborate, InBO ₃ , ScBO ₃ , YBO ₃ , LaBO ₃ , Mg ₃ (BO ₃ ) ₂ , Co ₃ (BO ₃ ) ₂ , diborate ( For example, Mg ₂ B ₂ O ₅ , Co ₂ B ₂ O ₅ ), metaborate (eg, LiBO ₂ , Ca (BO ₂ ) ₂ , NaBO ₂ , KBO ₂ ), tetraborate (eg, Na ₂ B _4). O ₇ · 10H ₂ O), pentaborate (eg, KB ₅ O ₈ · 4H ₂ O, Ca ₂ B ₆ O ₁₁ · 7H ₂ O, CsB ₅ O ₅ ), glyoxal, melamine / formaldehyde (eg, methylolmelamine) , Alkylated methylol melamine ), Methylolurea, resol resin, polyisocyanate, epoxy resin, etc. Among them, borax, boric acid, and borate are preferable because they rapidly cause a cross-linking reaction, and particularly a combination with polyvinyl alcohol as a water-soluble resin. And more preferably used.

  When gelatin is used as the water-soluble resin, the following compounds known as gelatin hardeners can be used as a crosslinking agent. For example, aldehyde compounds such as formaldehyde, glyoxal and glutaraldehyde; ketone compounds such as diacetyl and cyclopentanedione; bis (2-chloroethylurea) -2-hydroxy-4,6-dichloro-1,3,5- 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;

Isocyanate compounds such as 1,6-hexamethylene diisocyanate; Aziridine compounds described in US Pat. Nos. 3,017,280 and 2,983611; 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; chromium alum, potash alum, zirconium sulfate, chromium acetate and the like.
In addition, the said crosslinking agent may be single 1 type, or may combine 2 or more types.

The crosslinking agent solution is prepared by dissolving the crosslinking agent in water and / or an organic solvent.
As a density | concentration of the crosslinking agent in a crosslinking agent solution, 0.05-10 mass% is preferable with respect to the mass of a crosslinking agent solution, and 0.1-7 mass% is especially preferable.
As a solvent constituting the crosslinking agent solution, water is generally used, and an aqueous mixed solvent containing an organic solvent miscible with water may be used.
The organic solvent can be arbitrarily used as long as it can dissolve the cross-linking agent. For example, alcohols such as methanol, ethanol, isopropyl alcohol, and glycerin; ketones such as acetone and methyl ethyl ketone; methyl acetate, ethyl acetate, and the like An aromatic solvent such as toluene; an ether such as tetrahydrofuran; and a halogenated carbon-based solvent such as dichloromethane.

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

  Moreover, a benzotriazole type ultraviolet absorber, a salicylic acid type ultraviolet absorber, a cyanoacrylate type ultraviolet absorber, an oxalic acid anilide type ultraviolet absorber, etc. can be used. For example, JP-A 47-10537, 58-111942, 58-21284, 59-19945, 59-46646, 59-109055, 63-53544, and JP-B 36-36. 10466, 42-26187, 48-30492, 48-31255, 48-41572, 48-54965, 50-10726, U.S. Pat.No. 2,719,086, 3,707,375, 3,754,919, 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. Specific examples are described in JP-B 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.

The light resistance improvers may be used alone or in combination of two or more. This light resistance improver may be water-solubilized, dispersed, emulsified, or included in microcapsules.
The addition amount of the light fastness improver is preferably 0.01 to 10% by mass of the ink image-receiving layer coating solution.

In addition, for the purpose of improving the dispersibility of the inorganic pigment fine particles, various inorganic salts, pH adjusting agents, and the like may contain acids and alkalis.
In addition, various surfactants are used for the purpose of improving coating suitability and surface quality, and surfactants having ionic conductivity and metal oxide fine particles having electronic conductivity are used for the purpose of suppressing surface frictional charge and peeling charge. Various matting agents may be included for the purpose of reducing the frictional properties of the surface.

-Preparation of inkjet recording medium: WOW method-
As described above, it is preferable that a mordant and a crosslinking agent are introduced into the ink image-receiving layer in the course of applying the crosslinking agent solution. That is, the ink image-receiving layer is coated with an ink image-receiving layer coating solution containing inorganic pigment fine particles having an average primary particle diameter of 20 nm or less and a water-soluble resin, and at the same time as the coating or during the drying of the formed coating layer. Before the coating layer exhibits a reduced rate of drying, a solution containing a crosslinking agent capable of crosslinking a water-soluble resin and a mordant is applied to the coating layer, and then the coating layer to which the solution is applied is applied. It is preferably formed by a method of crosslinking and curing (WOW method; Wet On Wet method).

  The ink image-receiving layer of the ink jet recording medium of the present invention comprises a barrier liquid (provided that a crosslinking liquid is not reacted with a coating liquid containing inorganic pigment fine particles and a water-soluble resin and a solution containing a crosslinking agent). The mordant is contained in at least one of the solution containing the agent or the barrier solution.) And can be obtained by simultaneously applying and curing on the substrate (support).

  As described above, in the present invention, the water resistance of the ink image-receiving layer is improved by simultaneously applying the mordant together with the crosslinking agent. That is, when the mordant is added to the coating solution for the ink image-receiving layer, the mordant is cationic, and thus may coagulate in the presence of inorganic pigment fine particles having an anionic charge on the surface, such as silica. If a method including a mordant-containing solution and a coating solution for an ink image-receiving layer are prepared separately and applied individually, there is no need to consider aggregation of inorganic pigment fine particles, and the range of mordant selection is expanded. .

In the present invention, an ink image-receiving layer coating solution (hereinafter sometimes referred to as “ink image-receiving layer coating solution”) comprising at least inorganic pigment fine particles and a water-soluble resin is prepared, for example, as follows. it can.
That is, silica fine particles having an average primary particle diameter of 20 nm or less are added to water (for example, 10 to 20% by mass), and a high-speed rotating wet colloid mill (for example, Claremix (M Technique Co., Ltd.)) is used. For example, after being dispersed for 20 minutes (preferably 10 to 30 minutes) under high-speed rotation conditions of 10,000 rpm (preferably 5000 to 20000 rpm), an aqueous polyvinyl alcohol solution (for example, PVA having a mass of about 1/3 of silica) To the mixture, and further dispersion is performed under the same rotation conditions as described above. The obtained coating liquid is a uniform sol, and a porous ink image-receiving layer having a three-dimensional network structure can be formed by coating and forming this on a substrate (support) by the following coating method.
If necessary, a surfactant, a pH adjuster, an antistatic agent, and the like can be further added to the ink image-receiving layer coating solution.

  The ink image-receiving layer coating solution can be applied by a known coating method such as an extrusion die coater, an air doctor coater, a bread coater, a rod coater, a knife coater, a squeeze coater, a reverse roll coater, or a bar coater.

After coating the ink image-receiving layer coating solution, a crosslinking agent solution is applied to the coating layer, but the crosslinking agent solution is applied before the coating layer after coating reaches the reduced rate of drying. Also good. That is, it is preferably manufactured by introducing a cross-linking agent and a mordant after the ink image-receiving layer coating liquid is applied while the coating layer exhibits a constant rate of drying.
Here, “before the coating layer comes to exhibit a decreasing rate of drying” usually refers to several minutes immediately after the application of the ink image-receiving layer coating solution, and during this time, the solvent in the coated coating layer The constant rate drying rate, which is a phenomenon in which the content decreases in proportion to time, is shown. About the time which shows this constant rate drying rate, it describes in chemical engineering handbook (p.707-712, Maruzen Co., Ltd. issue, October 25, 1980).

  As described above, after the application of the ink image-receiving layer coating solution, the coating layer is dried until the coating layer exhibits a reduced rate of drying. The drying is generally performed at 50 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 the above range is appropriate.

  As a method of giving before the coating layer shows a decreasing rate of drying, (1) a method of further applying a crosslinking agent solution on the coating layer, (2) a method of spraying by a method such as spraying, ( 3) A method of immersing the substrate (support) on which the coating layer is formed in the crosslinking agent solution.

  In the method (1), examples of the application method for applying the crosslinking agent solution include curtain flow coaters, extrusion die coaters, air doctor coaters, bread coaters, rod coaters, knife coaters, squeeze coaters, reverse roll coaters, and bar coaters. A known coating method 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.

The coating amount of the coating liquid (crosslinking agent solution) containing at least a crosslinking agent and a mordant applied on the ink image-receiving layer is generally 0.01 to 10 g / m ^{2 in} terms of crosslinking agent. 05-5 g / m < ² > is preferable.

After the application of the crosslinking agent solution, it is generally heated at 40 to 180 ° C. for 0.5 to 30 minutes, and dried and cured. Especially, it is preferable to heat at 40-150 degreeC for 1 to 20 minutes.
For example, when borax or boric acid is used as the crosslinking agent contained in the crosslinking agent solution, heating at 60 to 100 ° C. is preferably performed for 5 to 20 minutes.

The crosslinking agent coating solution may be applied simultaneously with the application of the ink image-receiving layer coating solution.
In this case, an ink image-receiving layer coating solution and a crosslinking agent solution containing a crosslinking agent and a mordant are simultaneously coated (multilayered) on the substrate (support) so that the ink image-receiving layer coating solution is in contact with the substrate (support). The ink image-receiving layer can be formed by coating and then drying and curing.

The simultaneous coating (multilayer coating) can be performed by a coating method using, for example, an extrusion die coater or a curtain flow coater. After the simultaneous application, the formed application layer is dried. In this case, the drying is generally performed by heating the application layer at 40 to 150 ° C. for 0.5 to 10 minutes, preferably 40 to 100. It is carried out by heating at a temperature of 0.5 to 5 minutes.
For example, when borax or boric acid is used as the crosslinking agent contained in the crosslinking agent solution, it is preferable to heat at 60 to 100 ° C. for 5 to 20 minutes.

  When the simultaneous coating (multilayer coating) is performed by, for example, an extrusion die coater, the two types of coating liquid discharged at the same time are close to the discharge port of the extrusion die coater, that is, before moving onto the substrate (support). In this state, a multilayer is applied on the substrate (support). Since the two-layer coating liquid layered before coating is likely to cause a crosslinking reaction at the interface between the two liquids when transferred to the substrate (support), the two liquids are discharged near the discharge port of the extrusion die coater. May become mixed and thicken easily, which may hinder the application operation. Therefore, at the time of simultaneous application as described above, a barrier layer solution (intermediate layer solution) made of a material that does not react with the crosslinking agent, together with the application of the ink image-receiving layer coating solution and the crosslinking agent solution containing the crosslinking agent and mordant. It is preferable that a simultaneous triple layer coating is applied between the two liquids.

The barrier layer solution can be selected without particular limitation as long as it does not react with the crosslinking agent and can form a liquid film. For example, an aqueous solution containing a trace amount of a water-soluble resin that does not react with the crosslinking agent, water, and the like can be given. The water-soluble resin is used in consideration of applicability for the purpose of a thickener and the like, for example, hydroxypropyl methylcellulose, methylcellulose, hydroxyethylmethylcellulose, polyvinylpyrrolidone, gelatin And the like.
The barrier layer liquid may contain the mordant.

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

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

On the substrate (support), an undercoat layer may be provided for the purpose of improving the adhesion between the ink image-receiving layer and the substrate (support) or adjusting the electric resistance.
The ink image-receiving layer may be provided on only one surface of the substrate (support), or may be provided on both surfaces of the substrate (support) for the purpose of suppressing deformation such as curling. When the ink image-receiving layer is provided only on one side of the substrate (support), an antireflection film can be provided on the opposite side surface or both sides for the purpose of enhancing light transmittance.

  Examples of the present invention will be described below, but the present invention is not limited to these examples. In the following, “%” and “part” represent “% by mass” and “part by mass” unless otherwise specified.

<Example 1>
[Preparation of base paper]
As a pulp sample, wood pulp consisting of 100 parts of LBKP was beaten to 300 ml of Canadian freeness with a double disc refiner (adjusted blade shape and clearance appropriately adjusted), 0.5 parts of epoxidized behenamide, 1.0 part of anionic polyacrylamide , 0.1 part of polyamide polyamine epichlorohydrin and 0.5 part of cationic polyacrylamide were added at a dry mass ratio to pulp, and 15 parts of calcium carbonate as a filler (content in pulp slurry (solid content)): 12.8%) was added, and paper was made using a long paper machine to a basis weight of 150 g / m ² (density 0.91 g / m ² ) to obtain a base paper.

[Preparation of pigment coated paper (base material)]
(Formation of coat layer)
On both surfaces of the obtained base paper, a coating solution comprising the following components was applied and dried in line at a solid content of 10 g / m ² to form a coat layer (coating layer) on the felt surface (front surface) of the base paper.

<Coating layer coating solution A>
(1) Calcium carbonate 50 parts (2) Clay (Product name: Satinton 5HB, Hayashi Kasei Co., Ltd.) 50 parts (3) MBR latex (Product name: Nalstar MR-170, Nippon A & L Co., Ltd.) 45%) 12 parts (4) polyvinyl alcohol (product name: PVA-10, manufactured by Kuraray Co., Ltd., 10% aqueous solution) 5 parts (5) 100 parts of ion-exchanged water

(Calendar processing)
The base material on which the obtained coating layer was formed was calendered with a long nip calender so as to contact a metal roll having a surface temperature of 200 ° C., and the density was adjusted to 1.08 g / m ³ to obtain a pigment-coated paper. .

  It was 568 seconds when the Beck smoothness (JIS P 8119) of the felt surface of the obtained pigment coated paper was measured. Further, when SRa having a cutoff of 1 to 3 mm was measured by the above-described method, it was 0.61 μm.

[Production of polyolefin resin-coated paper (support for image recording material)]
After the corona discharge treatment is performed on both the felt surface and the wire surface (back surface) of the pigment-coated paper subjected to the calendar treatment, 70 parts of high-density polyethylene and 30 parts of low-density polyethylene are hot-melt extruder on the wire surface. Was coated to a thickness of 20 μm.
Furthermore, immediately after coating the felt surface with 100 parts of low density polyethylene containing 13.6 parts of anatase-type titanium oxide with a hot melt extruder to a thickness of 25 μm, various rules were applied to the surface of the felt surface. Various cooling processes were performed on the polyethylene surface while cooling using a cooling roll (temperature: 15 ° C.) having a typical unevenness height to produce a support for an image recording material. The difference in the molding was made by adjusting the density and the height of the unevenness. It was 188 seconds when the Beck smoothness (JIS P 8119) after the molding process was measured.

[Preparation of inkjet recording paper (medium)]
(1) and (2) in the following composition were mixed and dispersed for 20 minutes at a rotational speed of 10,000 rpm using a high-speed rotating colloid mill (CLEAMIX, manufactured by M Technique Co., Ltd.). 1) Ammonia water and the following (4) 9% aqueous solution of polyvinyl alcohol were added and further dispersed under the same conditions as above to prepare an ink image-receiving layer coating solution.
The mass ratio (PB ratio / (1) :( 4)) between the silica fine particles and the water-soluble resin was 3.5: 1.

<Composition of ink image-receiving layer coating solution>
(1) Silica fine particles 9.9 parts (average primary particle diameter 7 nm; Aerosil 300, manufactured by Nippon Aerosil Co., Ltd.)
(2) Ion-exchanged water 72.6 parts (3) 1N ammonia water (pH adjuster) 5.3 parts (4) Polyvinyl alcohol 9% aqueous solution (water-soluble resin) 31.4 parts (PVA420, manufactured by Kuraray Co., Ltd.) Saponification degree 81.8%, polymerization degree 2000)

The ink image-receiving layer coating solution obtained above was applied to the felt surface of the prepared image recording material support at an application amount of 200 ml / m ² using an extrusion die coater (application process), and applied to a hot air dryer. The coating layer was dried at 80 ° C. (wind speed 3 to 8 m / sec) until the solid concentration of the coating layer reached 20%. The coating layer showed a constant rate of drying during this period. Immediately after that, it was immersed in a crosslinking agent solution having the following composition for 30 seconds to deposit 20 g / m ² on the coating layer (step of applying a crosslinking agent solution), and further dried at 80 ° C. for 10 minutes (drying) Process). Thus, an ink jet recording sheet of the present invention was produced in which an ink image-receiving layer having a dry film thickness of 32 μm was provided on the surface of the substrate (support) on which the borax treatment was performed.

[Composition of crosslinking agent solution]
(1) Boron sand 6% 25 parts (2) Surfactant 10% aqueous solution 2 parts (F-144D, manufactured by Dainippon Ink & Chemicals, Inc.)
(3) Ion-exchanged water 68.3 parts (4) Polyallylamine 20% aqueous solution 3 parts (Mordant, molecular weight 5000)
(5) Polyfix 700 1.7 parts (Showa High Polymer Co., Ltd.)

(Evaluation)
The following evaluations were performed on the felt surfaces of the image recording material support and the ink jet recording paper after the molding process. The results are shown in Table 1 together with SRa and Beck smoothness of the felt surface of the base material and Beck smoothness (JIS P8119) of the felt surface of the polyolefin resin layer.

[Unerimula]
White light was projected onto a horizontally placed sample (support for image recording material and inkjet recording paper) at an angle of 30 °, and the state of the sample observed from the opposite angle was visually evaluated according to the following criteria.
5: No irregularities specific to the surface of the base paper are observed.
4: Tattice-like unevenness unique to the surface of the base paper is hardly observed.
3: Slight irregularities peculiar to the surface of the base paper are observed, but are within an allowable range.
2: Tattice-like irregularities unique to the surface of the base paper are very conspicuous and out of the allowable range.
1: Tattice irregularities unique to the surface of the base paper are extremely conspicuous.

[Glitter]
White light was projected onto a horizontally placed sample (support for image recording material and inkjet recording paper) at an angle of 30 °, and the state of the sample observed from the opposite angle was visually evaluated according to the following criteria.
5: I don't care about uneven gloss and glare.
4: The gloss unevenness and glare are scarcely concerned.
3: Gloss unevenness and glare are slightly observed, but are within an allowable range.
2: Uneven gloss and glare are noticeable and out of the allowable range.
1: Uneven gloss and glare are extremely noticeable.

[Sharpness]
Using an inkjet printer (“PM-900C” manufactured by Seiko Epson Corporation) on the obtained inkjet recording paper, 10 1 mm fine lines were printed at 1 mm intervals (black dye), and the sharpness of the fine lines was as follows: Visual evaluation was performed based on the standard.
5: The fine line is very sharp.
4: The fine line is sharp.
3: The sharpness of the thin line is slightly lacking, but is within an allowable range.
2: The sharpness of the fine line is lacking and is outside the allowable range.
1: The sharpness of the thin line is extremely inferior.

<Example 2>
In Example 1, in the formation of the coating layer in the production of the pigment-coated paper, the coating amount of the coating layer coating liquid A was changed to 23 g / m ² in terms of solid content, and further used for the production of a support for an image recording material. Except that the roughness of the cooling roll was changed in order to adjust the Beck smoothness (JIS P8119) of the felt surface of the polyolefin resin layer, the support for image recording material and the inkjet recording paper were the same as in Example 1. The same evaluation was performed.

<Example 3>
In Example 1, in the formation of the coating layer in the preparation of the pigment coated paper, the coating amount of the coating layer coating solution A was changed to 18 g / m ² in terms of solid content, and immediately after the coating layer coating solution A was applied, A support for image recording material and inkjet recording paper were prepared in the same manner as in Example 1 except that they were cast and dried, and the same evaluation was performed.

<Example 4>
In Example 1, in the formation of the coating layer in the preparation of the pigment-coated paper, the coating amount of the coating layer coating solution A was changed to 25 g / m ² in terms of solid content, and immediately after the coating layer coating solution A was applied, A support for an image recording material and an ink jet recording paper were prepared in the same manner as in Example 1 except that it was cast and dried, and the same evaluation was performed.

<Example 5>
An image was obtained in the same manner as in Example 1 except that the base paper was changed to a white (opaque) polyester film (thickness 150 μm) containing 10% by mass of TiO ₂ and no coating layer was formed. A support for recording material and ink jet recording paper were prepared and subjected to the same evaluation.

<Comparative Example 1>
In Example 1, the base paper was used without forming a coating layer, and the roughness of the cooling roll used for the production of the support for the image recording material was determined using the Beck smoothness (JIS P8119) of the felt surface of the polyolefin resin layer. A support for an image recording material and an inkjet recording paper were produced in the same manner as in Example 1 except that the change was made for adjustment, and the same evaluation was performed.

<Comparative example 2>
In Example 1, except that the base paper having a density of 1.03 g / m ² was used without forming a coating layer, and the cooling roll used for producing the image recording material support was changed to a mirror roll, In the same manner as in Example 1, a support for an image recording material and an ink jet recording paper were prepared, and the same evaluation was performed.

<Comparative Example 3>
An image recording material was prepared in the same manner as in Example 1 except that the base paper having a density of 0.98 g / m ² was used as it was without forming a coating layer and no polyolefin resin was coated. Supports and inkjet recording papers were prepared and subjected to the same evaluation.

<Comparative example 4>
In Example 1, the raw paper was changed to a biaxially stretched transparent polyester film (thickness: 200 μm), used without forming a coating layer, and the same as in Example 1 except that the polyolefin resin was not coated. Thus, a support for an image recording material and an inkjet recording paper were prepared, and the same evaluation was performed.

<Comparative Example 5>
A support for an image recording material in the same manner as in Example 1, except that the base paper was changed to a biaxially stretched transparent polyester film (thickness: 160 μm) and used without forming a coating layer. And the inkjet recording paper was produced and the same evaluation was implemented.

<Comparative Example 6>
In Example 5, an image recording material support and inkjet recording paper were prepared in the same manner as in Comparative Example 5 except that the cooling roll used for the production of the image recording material support was changed to a mirror surface roll. Evaluation was performed.

  As is apparent from Table 1, the substrate for the image recording material of the present invention in which the base material is a coated paper or an opaque film, and subjected to a mold forming process, and the ink jet recording paper using the same are all unilima, glare and sharpness. Is found to be good.

Claims (7)

A support for an image recording material in which both surfaces of a substrate are coated with a polyolefin resin,
The substrate is made of coated paper or opaque film,
A support for an image recording material, characterized in that the surface of the polyolefin resin covering the substrate on the side on which the image receiving layer is provided is a rough surface subjected to a die-molding process.   The Beck smoothness (JIS P 8119) of the surface of the substrate on the side where the image receiving layer is provided is 600 seconds or more, and the Beck smoothness of the surface of the polyolefin resin which coats the substrate on the side of providing the image receiving layer. 2. The support for image recording material according to claim 1, wherein (JIS P 8119) is 20 to 500 seconds.   The center surface average roughness (SRa value) of the surface on the side of the substrate on which the image receiving layer is provided is less than 0.75 μm when measured under conditions of a cutoff of 1 to 3 mm. Or a support for an image recording material described in 2.   2. The electrophotographic image-receiving material, heat-sensitive color-developing recording material, sublimation transfer image-receiving material, thermal transfer image-receiving material, silver salt photographic light-sensitive material, and ink-jet recording medium. The support for image recording materials as described in any one of -3.   The support for an image recording material according to claim 4, which is used as a support for an inkjet recording medium. An image recording material having a support and at least one image receiving layer on the support,
An image recording material comprising the support for an image recording material according to claim 4 as the support. An inkjet recording medium having a support and at least one ink image-receiving layer on the support,
An inkjet recording medium comprising the support for an image recording material according to claim 5 as the support.