JP3407250B2 - Recording medium - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an inkjet recording medium.

[0002]

2. Description of the Related Art Ink jet printers have become rapidly popular in recent years because they are easy to achieve full color printing and have low printing noise. The inkjet method is a method of ejecting ink droplets from a nozzle toward a recording material at high speed, and the ink contains a large amount of solvent. Therefore, the recording medium for an inkjet printer is
It is required to quickly absorb the ink and to have excellent color development.

As a recording medium, there has been proposed a recording medium having a porous ink-receiving layer on which a pigment is bonded with a hydrophilic resin provided on a substrate. Due to the porous structure, it tends to have excellent ink absorbency and ink dryness.

Since the printer using the ink jet system is easily enlarged, it is widely used in the industrial field, particularly in outdoor signboards.
Due to the lack of water resistance and the lack of light resistance of the ink, some surface treatment is required after printing. As the surface treatment method, (1) a transparent film is laminated, (2) a transparent film, a transparent resin or the like is placed on the surface, and (3) a transparent resin or the like is applied and dried. Among them, the method (3) has a problem that it is difficult to apply it uniformly, and the methods (1) and (2)
The method (1) causes a problem that the sharpness of the image is deteriorated.

[0005]

DISCLOSURE OF THE INVENTION The present invention is directed to a recording medium having a water-proof treatment after printing, particularly a printing quality after laminating a transparent film, particularly a good coloring density.

[0006]

As a result of keen research on the above problems, the inventor of the present invention has found that in a recording medium having an ink receiving layer on a substrate, the color density A and the black density of a solid print portion with black ink are black. When the relationship of the color density B after being laminated on the portion solidly printed with ink is A> 1.3, B>
It has been found that a good printing quality can be obtained after a good lamination by having a value of 1.15 × A.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below.
In the present invention, the base material is not particularly limited, for example, natural paper, synthetic paper, cloth, non-woven fabric, wood,
Examples include metal, glass, artificial leather, natural leather, and those obtained by laminating any two or more of these.
Preferably, it is a plastic film, and the base resin of the film used is not particularly limited, and examples thereof include polyolefin resin, polyamide resin, polyacrylic resin, polyurethane resin, polyvinyl resin, polyether resin. Resins, polystyrene resins, and the like can be mentioned, but polyester resins described below are particularly preferable.

The polyester in the present invention means an aromatic dicarboxylic acid such as terephthalic acid, isophthalic acid or naphthalenedicarboxylic acid or an ester thereof and a glycol such as ethylene glycol, diethylene glycol, 1,4-butanediol or neopentyl glycol. It is a polyester produced by condensation. These polyesters include a method of directly reacting an aromatic dicarboxylic acid and a glycol, or an ester exchange reaction of an alkyl ester of an aromatic dicarboxylic acid and a glycol followed by polycondensation, or a diglycol ester of an aromatic dicarboxylic acid. Can be produced by a method such as polycondensing. Typical examples of such polyesters include polyethylene terephthalate, polyethylene butylene terephthalate or polyethylene-2,6-naphthalate. This polyester may be a homopolymer or a copolymer of a third component. In any case, in the present invention, a polyester having an ethylene terephthalate unit, a butylene terephthalate unit or an ethylene-2,6-naphthalate unit in an amount of 70 mol% or more, preferably 80 mol% or more, more preferably 90 mol% or more is preferable. .

In the present invention, the base material is preferably a cavity-containing film described below, more preferably a cavity-containing polyester film. The method of containing cavities is not particularly limited, but preferably the following polyester is mixed with an incompatible thermoplastic resin, melted, and extruded at least uniaxially by stretching the extruded sheet This is a method of containing many fine cavities.

The thermoplastic resin which is incompatible with the polyester used in the present invention must be one which is incompatible with the above-mentioned polyester. Specifically, polystyrene resin, polyolefin resin, polyacrylic resin,
Examples thereof include polycarbonate resin, polysulfone resin, and cellulose resin. Especially polystyrene resin,
Polyolefin resins such as polymethylpentene and polypropylene are preferred.

The polymer mixture obtained by mixing the polyester of the present invention and an incompatible thermoplastic resin to the polyester is prepared by, for example, mixing chips of each resin, melt-kneading in an extruder, and then extruding and solidifying. Method, or a method in which both resins are kneaded in advance by a kneader and further melt-extruded by an extruder to solidify, or an incompatible thermoplastic resin is added to the polyester in the polyester polymerization step and dispersed by stirring. It can also be obtained by a method of melt-extruding and solidifying the obtained chips. The polymer obtained by solidification (unstretched sheet) is usually in a non-oriented or weakly oriented state. Further, the thermoplastic resin incompatible with the polyester is present in the polyester in a form dispersed in various shapes such as a spherical shape, an elliptic spherical shape, or a thread shape.

The amount of the thermoplastic resin which is incompatible with the polyester and is mixed with the polyester varies depending on the amount of the target cavities, but is 3 with respect to the entire polymer mixture.
% To 39% by weight is preferable, and 6 to 35% by weight is particularly preferable. If it is less than 3% by weight, there is a limit to increase the amount of cavities generated, and the desired flexibility, lightness, and drawability cannot be obtained. On the other hand, when it is 40% by weight or more, the heat resistance and strength of the polyester film, particularly the strength of the waist, are significantly impaired.

If necessary, the polymer mixture may contain inorganic particles in order to improve the hiding property and the drawing property. Examples of the inorganic particles for this purpose include titanium dioxide, silicon dioxide, calcium carbonate, barium sulfate, aluminum oxide, kaolin, and talc, but are not particularly limited.

It is possible to add a colorant, a light-proofing agent, a fluorescent agent, an antistatic agent, etc. to the polymer mixture depending on the application.

In the present invention, a so-called composite film in which a surface layer and a central layer are laminated may be used. The method is not particularly limited. However, from the viewpoint of productivity, it is most preferable to use a so-called co-extrusion method in which the raw materials for the surface layer and the central layer are extruded from different extruders, introduced into one die to obtain an unstretched sheet, and then oriented at least uniaxially. . The void-containing film of the present invention may be a single layer film or a composite film having two or more layers.

A recording layer is provided on the recording medium of the present invention.
The recording layer is preferably composed of particles and a resin. Further, the resin preferably comprises a water-soluble resin, a curing agent and a cationic substance. As the water-soluble resin, known ones can be used, for example, polyester resin, polyurethane resin,
One or more of resins such as polyester urethane resin, acrylic resin, polyvinyl alcohol, acrylic resin, starch, polyvinyl butyral, gelatin, casein, ionomer, gum arabic, carboxymethyl cellulose, polyvinylpyrrolidone, polyacrylamide, and styrene-butadiene rubber Can be used if desired.
For inkjet recording, it is preferably polyvinyl alcohol and / or polyvinylpyrrolidone. As the curing agent, any known one can be used as long as it cures a water-soluble resin, for example, melamine resin, epoxy resin, blocked isocyanate group-containing resin, glyoxal, isoban, borax, etc., but preferably water-soluble. It is a melamine resin. The mixing amount varies depending on the type of the cross-linking agent, but is preferably such that the water-soluble resin becomes insoluble in water. If it is added in excess, the hydrophilic groups of the water-soluble resin will react excessively, and the hydrophilicity will decrease, leading to a problem that the ink absorbency will decrease.

As the cationic substance, known substances can be used, for example, cation-modified polyvinyl alcohol,
Cation-modified polyester, cation-modified polyamide,
Any cation-modified surfactant such as a diallylamine polymer, a dimethyldiallylammonium chloride polymer, or a cation-modified surfactant can be used without limitation. The mixing amount is preferably 5% by weight to 50% by weight with respect to the water-soluble resin. When the mixing amount is small, the fixability of the ink is poor, and when the mixing amount is large, there is a problem that the strength of the ink receiving layer is lowered.

The particles may be either organic or inorganic, and examples thereof include titanium dioxide, calcium carbonate, silicon dioxide, barium sulfate, aluminum oxide, aluminum hydroxide, zeolite, zinc oxide, benzoguanamine particles,
The crosslinked acrylic particles and the crosslinked styrene particles are not particularly limited. Further, these may be used alone or in combination of two or more. The average particle size of the particles used is not particularly limited, but is preferably 0.2 μm or more and 20 μm or less, more preferably 2 μm or more and 15 μm or less.

In the present invention, it is preferable that the particle size does not include particles having a particle size of 35 μ or more. When the particles used have a wide particle size distribution, particles having a particle size of 35 μm or more may be contained in the ink receiving layer. In that case, it is preferable to remove the particles by classification or the like. The presence of particles of 35 μm or more facilitates the formation of protrusions on the surface of the ink receiving layer, and when laminating, a gap is generated between the laminate film and the ink receiving layer. This gap reduces the color density after lamination.

In the present invention, the weight ratio of the resin to the particles is preferably 1 / 1.5 to 1 / 2.5. 1 / 1.5
If it is less than 1, there is a problem that the ink drying rate is low, and conversely, if it is more than 1 / 2.5, there is a problem that the color density is lowered.

The ink receiving layer may be composed of one layer,
Further, it may have a structure of two or more layers. The method of providing the ink receiving layer is not particularly limited, gravure coating method, kiss coating method, dip method, spray coating method, curtain coating method, air knife coating method, blade coating method, reverse roll coating method,
A commonly used method such as a bar coat method can be applied.

Care must be taken when applying and drying the ink receiving layer. If dried quickly, the surface will become rough,
On the contrary, if it is gradually dried, it is leveled in the drying process and a smooth surface is obtained. If unevenness exists on the surface, a gap is created during lamination, and the color density after lamination is reduced. The effect of this drying is remarkable when huge particles, particularly particles having a size of 35 μm or more are present in the coating liquid.

The coating amount of the ink receiving layer in the recording medium of the present invention is not limited, but is preferably 10 to 25 g / m ² . If it is less than 10 g / m ² , the ink absorption speed is slow and bleeding becomes large. If it exceeds 25 g / m ² , the color density becomes low.

The preferred void-containing film of the present invention has an apparent specific gravity of 0.5 or more and 1.3 or less, preferably 0.9 or more and 1.3 or less, more preferably 1.05 or more and 1.27 or less. It costs. When the apparent specific gravity is less than 0.6, the void content is too large, the strength of the film is significantly impaired, and cracks or wrinkles are easily generated on the film surface. On the other hand, when the apparent specific gravity exceeds 1.3, the void content becomes too small, and the properties such as cushioning property and flexibility caused by the inclusion of voids are impaired. The method for lowering the specific gravity is not particularly limited, but preferably, the polyester contains an incompatible resin and / or inert particles in the polyester, and the fine particles are internally formed by at least uniaxial orientation. It is a polyester film for recording, which contains a polyester film containing various cavities. As the incompatible resin and particles in this case, known ones can be used. Preferred are polystyrene resins, titanium dioxide, and calcium carbonate.

An anchor layer may be provided on the base film to improve the adhesion between the base and the ink receiving layer.
As the compound that constitutes the anchor layer, polyester resin, polyurethane resin, polyester urethane resin,
It is to contain at least one kind of acrylic resin and melamine resin.

The polyester resin of the anchor coat layer is a polyester resin composed of dibasic acid and glycol, which is soluble, emulsifiable or dispersible in water. For example, the dibasic acid is 50 to 0.5 mol% of the total dicarboxylic acid. Is a sulfonic acid group-containing dicarboxylic acid, and is a polyester copolymer obtained by copolymerizing these two dicarboxylic acid components and a glycol component. Examples of the dicarboxylic acid containing a metal salt of sulfonic acid include sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfophthalic acid, 4-sulfonaphthalene-
Examples thereof include metal salts such as 2,7-dicarboxylic acid and 5 [4-sulfophenoxy] isophthalic acid, with 5 being particularly preferable.
-Sodium sulfoisophthalic acid, sodium sulfoterephthalic acid.

These sulfonic acid metal salt-containing dicarboxylic acids account for 50 to 0.5 mol%, preferably 20 to 1 mol%, based on the total dicarboxylic acid components. Above 50 mol%, the dispersibility in water is high. Even if it improves, the water resistance of the copolymer decreases. The dispersibility of the polyester copolymer in water varies depending on the copolymerization composition, the type and amount of the water-soluble organic compound, etc., but the amount of the sulfonic acid metal group-containing dicarboxylic acid component does not impair the dispersibility in water. , Less is better.

As the normal dicarboxylic acid containing no metal sulfonate group, aromatic, aliphatic and alicyclic dicarboxylic acids are used. Aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, orthophthalic acid,
2,6-naphthalenedicarboxylic acid and the like can be mentioned. These aromatic dicarboxylic acids are preferably 40 mol% or more of the total dicarboxylic acid components, and 40 mol%
If it is less than the above range, the mechanical strength and water resistance of the polyester copolymer are deteriorated.

As the aliphatic or alicyclic dicarboxylic acid,
Examples thereof include succinic acid, adipic acid, sebacic acid, 1.3-cyclopentanedicarboxylic acid, 1.2-cyclohexanedicarboxylic acid, 1.3-cyclodicarboxylic acid and 1.4-cyclohexanedicarboxylic acid. The addition of these non-aromatic dicarboxylic acid components may improve the adhesive performance, but generally the mechanical strength and water resistance of the polyester copolymer deteriorate.

The glycol component to be reacted with the above dicarboxylic acid mixture is an aliphatic glycol having 2 to 8 carbon atoms, an alicyclic glycol having 6 to 12 carbon atoms, and a mixture of both, such as ethylene glycol and 1.2-propylene. Examples thereof include glycol, 1.3-propanediol, 1.4-butanediol, neobenzyl glycol, 1.6-hexanediol, 1.2-cyclohexanedimethanol, 1.4-cyclohexanedimethanol and p-xylene glycol. Examples of the aliphatic diol having 4 or more carbon atoms include diethylene glycol and triethylene glycol, and examples of the polyether include polyethylene glycol, polypropylene glycol and polytetramethylene glycol.

The polyester copolymer can be obtained by usual melt polycondensation. That is, a direct esterification method in which the above-mentioned dicarboxylic acid component and glycol component are directly reacted to remove water to esterify and then polycondensate, or a dimethyl ester of the dicarboxylic acid component and a glycol component are reacted to distill methyl alcohol It can be obtained by the transesterification method in which the ester is removed and the ester is exchanged, followed by polycondensation. In addition, the polymer can be obtained by solution polycondensation, interfacial polycondensation, etc., and the present invention is not limited to any one of the above methods. At the time of melt polycondensation, an antioxidant, a slip agent, inorganic fine particles and an antistatic agent can be added if necessary. The above-mentioned polyether such as polyethylene glycol can be added by melt blending during melt polycondensation or after polymerization.

The polyurethane resin includes (1) a compound having two or more active hydrogen atoms in the molecule, (2) an organic polyisocyanate having two or more isocyanate groups in the molecule, or (3) an intramolecular compound. Is obtained by reacting with a chain extender having at least two active hydrogen atoms, and has a terminal isocyanate group.

The compounds generally known as the above-mentioned compound (1) are those containing two or more hydroxyl groups, carboxyl groups, amino groups or mercapto groups at the end or in the molecule, and particularly preferred are polyethers. Examples thereof include polyols, polyester polyols and polyether ester polyols. As the polyether polyol, for example, a compound obtained by polymerizing alkylene oxides such as ethylene oxide and propylene oxide, or styrene oxide and epichlorohydrin, or their random copolymerization, block copolymerization or addition polymerization to a polyhydric alcohol is performed. There are compounds obtained and the like.

The polyester polyol and the polyether ester polyol mainly include linear or branched compounds such as succinic acid, adipic acid,
Polyvalent saturated and unsaturated carboxylic acid anhydrides such as phthalic acid and maleic anhydride and polyvalent saturated and unsaturated carboxylic acid anhydrides such as ethylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol and trimethylolpropane It can be produced by condensing saturated and unsaturated alcohols, polyalkylene ether glycols such as relatively low molecular weight polyethylene glycol and polypropylene glycol, or a mixture of these alcohols. Further, polyester polyols include polyesters obtained from lactones and hydroxy acids, and polyether ester polyols include polyether esters obtained by adding ethylene oxide or propylene oxide to previously produced polyesters. .

As the organic polyisocyanate of the above (2), isomers of toluylene diisocyanate, 4,
Aromatic diisocyanates such as 4'-diphenylmethane diisocyanate, aromatic aliphatic diisocyanates such as xylylene diisocyanate, isophorone diisocyanate, and aliphatic diisocyanates such as 4,4'-dicyclohexylmethane diisocyanate, or a single compound thereof. Examples thereof include polyisocyanates preliminarily added with trimethylolpropane and the like.

As the chain extender having at least two active hydrogens in the above (3), ethylene glycol, diethylene glycol, 1,4-butanediol and 1,6
-Glycols such as hexanediol, glycerin,
Examples include polyhydric alcohols such as trimethylolpropane and pentaerythritol, diamines such as ethylenediamine, hexamethylenediamine and piperazine, aminoalcohols such as monoethanolamine and diethanolamine, thiodiglycols such as thiodiethyleneglycol, and water. .

The polyacrylic resin can be obtained by polymerizing acrylic acid or a derivative thereof and, if necessary, a monomer other than acrylic acid (derivative) having a vinyl group. Examples of the monomer used include acrylic acid, methacrylic acid (hereinafter, acrylic acid and / or methacrylic acid are referred to as (meth) acrylic acid), a lower alkyl ester of (meth) acrylic acid (eg, methyl, ethyl, propyl). , Butyl, amyl, hexyl, hebutyl, octyl,
2-ethylhexyl ester), methyl methacrylate, hydroxymethyl acrylate, styrene, glycidyl methacrylate, methyl acrylate, ethyl acrylate and the like. The melamine resin may be water-soluble, water-insoluble, or a combination thereof.

If necessary, particles having an average particle size of 0.1 μm or more, preferably particles having an average particle size of 0.3 μm or more may be contained in the intermediate layer and / or the ink receiving layer. Particles that can be added include silica, kaolinite, talc,
Examples include calcium carbonate, zeolite, alumina, barium sulfate, carbon black, zinc oxide, titanium oxide, and organic white pigments (crosslinked acrylic particles, crosslinked styrene particles), but are not particularly limited. If it is less than 0.1 μm, the drawability with a pencil is insufficient.

As a method for providing the anchor coat layer, a commonly used method such as a gravure coat system, a kiss coat system, a dip system, a spray coat system, a curtain coat system, an air knife coat system, a blade coat system and a reverse roll coat system. Can be applied.
As the step of applying, any method such as a method of applying before stretching the film, a method of applying after longitudinal stretching, a method of applying to the film surface after the orientation treatment, and the like are possible. In the present invention, preferably, the adhesive layer C is provided.

The pressure-sensitive adhesive used in the pressure-sensitive adhesive layer C is not particularly limited, and examples thereof include natural rubber, synthetic rubber, chloroprene rubber, NBR, butyl rubber, urethane rubber, vinyl acetate and its copolymers, acrylic acid and its copolymers. Solvent-based adhesives such as coalescing, natural rubber latex, chloroprene latex, NBR latex, vinyl acetate and its copolymers, emulsion adhesives such as acrylic acid and its copolymers, water-soluble polyvinyl alcohol, starch, glue etc. Adhesive, thermosetting resin such as epoxy resin, polyester resin, urea and melamine resin, phenol resin, polyurethane resin, paraffin wax,
The heat-melting adhesive such as microcrystalline wax, asphalt, resin wax mixture, polyethylene, unsaturated polyester, etc. are not particularly limited. Further, these may be used alone or in plural. Further, a third component such as a curing agent or a filler may be included. Further, these may be provided on the anchor coat layer.

In the present invention, the release layer D is preferably provided. The release layer D is not particularly limited, and known materials can be used.

[0042]

EXAMPLES Examples and comparative examples of the present invention will be described below. First, the measurement / evaluation methods used in the present invention are shown below.

1) Printing computer: Macintosh application: Adobe Illustrator 7.0
J image: K100% Printer: Inkjet printer (CJ-70 manufactured by Roland DG Corporation)

2) The film printed by the laminating treatment 1) is placed in an environment of 25 ° C. × 60% for 8 hours.
After drying for an hour, place it on a flat glass plate and attach a 24 mm width cellophane tape manufactured by Nichiban Co., Ltd. to the black solid printing part.
A rubber roll of 5 kg reciprocated 10 times.

3) The recording medium printed with the color density (1) was dried in an environment of 25 ° C. × 60% for 8 hours, and after laminating in 2), the reflection density was measured with a Macbeth densitometer TR-927. did.

4) Printing a photographic image using the printer having the printing characteristics (1),
After leaving it to stand for a while to dry it, it was laminated with a laminate film (G-002PV50) manufactured by Lintec Co., Ltd., and then observed, and a good printed matter excellent in color development was indicated by ○, and a slightly inferior but no problem printed matter. If it was a poorly colored printed matter, it was evaluated as Δ.

Example 1 100 μ polyester synthetic paper (Crisper G121
1. 10% by weight of melamine resin (Sumitex M-3 manufactured by Sumitomo Chemical Co., Ltd.) and catalyst (Sumitex manufactured by Sumitomo Chemical Co., Ltd.) on the corona treated surface of 1.
ACX) 1% by weight is mixed with 89% by weight of water to give 0.1 g /
It was applied so as to be m ² (when dried). In addition, polyvinyl alcohol (Kuraray Co., Ltd., RS-117), cross-linking agent ( non-formalin type special reactive resin; Sumitomo Chemical Co., Ltd. , Sumirez resin SR5004), cationic resin ( quaternary ammonium) Salt polymer; Senka Co., Ltd.
Ltd., Papiogen P105), surfactant (perfluoro
Alkyl ethylene oxide; manufactured by Dainippon Ink and Co., Ltd. , Megafac F-1405), silica particles having an average particle size of 5 μm (Fuji Silysia, Syloid 450) and silica particles having the same 12 μm (Fuji Silysia, Syloid 470, 30 μ or more). 1) for each final solid content
It was adjusted to a 10% aqueous solution so as to be 00/70/30/5/160/160 (weight ratio), coated with a wire bar, dried in a gear oven at 90 ° C. for 5 minutes, and the coating amount was 15 g / m. ^A recording medium was obtained by setting it to ² .

Examples 2 to 4 Recording media were obtained in the same manner as in Example 1 except that the raw material composition ratio, the drying temperature and the coating amount were set as shown in Table 1.

Comparative Examples 1 and 2 A recording medium was obtained in the same manner as in Example 1 except that the raw material composition ratio, the drying temperature, and the coating amount were set as shown in Table 1.

Comparative Example 3 A recording medium was obtained in the same manner as in Example 1, except that the particles of 30 μm or larger were not classified.

[0051]

[Table 1]

The evaluation results are shown in Table 2.

[0053]

[Table 2]

[0054]

INDUSTRIAL APPLICABILITY The present invention provides a recording medium in which the solid printed portion has a high color density and the image after lamination is good.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-10-52971 (JP, A) JP-A-10-52970 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B32B 1/00-35/00 B41M 5/00

Claims (7)

(57) [Claims] 1. A porous material mainly composed of particles and a resin on a base material.
Inkjet recording provided with an ink receiving layer having a structure
In the medium for use , the particles are large particles having a particle size of 35 μm or more.
Containing particles obtained by removing the
When the black ink is printed on the ink receiving layer
A color density A black solid print portion, the relationship of the color density B after the lamination process to said black solid printing portion, the following formulas (1) and
An ink jet recording medium characterized by satisfying (2) . A> 1.3 (1) B> 1.15 × A (2) 2. The weight ratio of resin to particles is 1 / 1.5 to 1 /
2.5 a Inkuji according to claim 1, characterized in that
Jet recording medium. 3. The coating amount of the ink receiving layer is 10 to 25 g.
/ M ^{2 according} to claim 1 or 2 , characterized in that
Inkjet recording medium. 4. claims 1-3 in which the substrate is characterized in that it is a plastic film oriented in at least one axis
The inkjet recording medium according to any one of 1 to 3 above . 5. A polyester film comprising a polyester film in which a thermoplastic resin incompatible with the polyester is mixed, melted, extruded, and oriented at least uniaxially to have fine voids inside. The ink jet recording medium according to claim 4, characterized in that
body. 6. The ink jet recording medium according to any one of claims 1 to 5 , wherein a recording layer is provided on at least an anchor coat layer provided on a base film. . 7. The anchor coat layer is a polyester resin,
The inkjet recording medium according to claim 6, further comprising at least one of a polyurethane resin, a polyacrylic resin, and a melamine resin .