JP2003127521A - Ink jet recording medium for non-aqueous pigment ink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording medium having excellent concentration, minuteness of a recording image, fixability or the like of a coloring agent in the medium having a gloss on the surface used for ink jet recording by using a non-aqueous ink. SOLUTION: The ink jet recording medium ink jet records by using the non-aqueous pigment ink containing a color material pigment, a high melting point solvent and a resin composition soluble in the high melting point solvent. The recording medium comprises at least one or more coating layers coating on a support. The coating layer contains inorganic fine particles having a mean particle size of 100 nm or less and a peak of a hole size distribution in the range of 2 to 60 nm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet recording medium. More specifically, color material pigments,
The present invention relates to an inkjet recording medium having a glossy surface, which is used for inkjet recording using a non-aqueous pigment ink containing a high boiling point solvent and a resin composition.

[0002]

2. Description of the Related Art Ink jet recording is a recording of images, characters, etc. by ejecting minute droplets of ink by various operating principles and adhering them to a recording medium such as paper. Inkjet recording has features such as high speed, low noise, easy multicoloring, great flexibility in recording patterns, and no need for development-fixing. It can be used as a recording device for characters, graphics, color images, etc. for various purposes. Is rapidly spreading in.

Conventionally, in ink jet recording, water-based ink, that is, water or a mixed solvent of water and a hydrophilic solvent, is used.
Inks in which colorants such as dyes and pigments are dispersed or dissolved have been used. However, ink jet recording using a water-based ink has various problems that occur when the printing portion of the recording medium absorbs and expands the solvent in the ink. The elongation of the recording medium is caused by the hydrogen bond between the fibers maintaining the mechanical strength of the support being cut by the solvent of the water-based ink, particularly water, which adversely affects the transportation of the recording medium in the printer. In addition to degrading the accuracy of the relative positional relationship between the print head and the recording medium in the printer, it causes undesired phenomena such as a decrease in the dimensional accuracy of the resulting drawing and unevenness in the image. ing.

To solve such a problem, Japanese Patent Laid-Open No. 57-1
No. 0660, No. 57-10661, JP-A-5
JP-A-202324 and JP-A-5-331397 propose to use a non-aqueous ink in which a colorant is dissolved or dispersed in a non-aqueous solvent such as isoparaffin hydrocarbon. According to these proposals, it is possible to carry out ink jet recording which does not involve expansion of the recording medium at all, has high dimensional accuracy, and causes no image unevenness. Furthermore, due to the low viscosity and low surface tension that are characteristic of non-aqueous solvents, it is possible to increase the drive frequency of the print head compared to inkjet recording using water-based ink, resulting in extremely high-speed inkjet recording. It can be carried out.

As such a non-aqueous ink, there is a non-aqueous dye ink in which an oil-soluble dye as a colorant is dispersed or dissolved in a high boiling point solvent. However, in this type of ink, the high boiling point solvent stays in the recording medium forever, so that the dye easily moves in the recording medium over time, and image bleeding becomes a serious problem. In general, oil-soluble dyes have weak light resistance like water-soluble dyes, and there is a demand for further improvement in various properties in the industrial field where weather resistance is required.

On the other hand, a non-aqueous pigment ink using a pigment instead of a dye as a colorant has been proposed for the purpose of improving image bleeding and weather resistance.

A recording medium used for ink jet recording using such a non-aqueous ink is disclosed in Japanese Patent Laid-Open No. 64-2478.
No. 5, etc., proposes a recording medium composed of an oil-absorbing inorganic pigment, an organic pigment and a water-based adhesive.
In JP-A-255580, a recording medium composed of silica and an adhesive is proposed. These recording media are
The recording medium was a so-called mat coat type recording medium having a matte appearance on the recording surface.

On the other hand, with the recent progress of ink jet printers, it has become possible to obtain high-definition images comparable to silver halide photographs. Along with this, an inkjet recording medium having a texture similar to that of a silver halide photographic print, that is, having a glossy surface, has been desired.
Naturally, such a recording medium has gloss and at the same time has a high density of the recorded image and a high definition of the recorded image, that is, the circumference of each dot is smooth and the contour is sharp, Moreover, it is required that the ink does not repel or flow, and that the image has excellent storability, that is, the fixing property of the colorant is high.

In response to such a demand, in the ink jet recording using a water-based ink, JP-A-63-26
5680, Japanese Patent Application Laid-Open No. 5-59694 and the like propose an inkjet recording medium provided with a coating layer by a cast coating method, and Japanese Patent Laid-Open No. 6-155892 and the like disclose polyvinyl alcohol on the same recording medium. A recording medium having a film formed of a water-soluble polymer, such as, is proposed. According to these proposals, it has a high gloss,
Although an inkjet recording medium having a high absorbability for water-based ink is obtained, even if an attempt is made to record with a non-aqueous ink on these recording mediums, the material forming the recording medium and the solvent contained in the ink or Since there is no affinity with the colorant, the ink components cannot penetrate into the recording medium from the surface of the recording medium, the ink is repelled on the surface of the recording medium, and a low image density is obtained, and unevenness occurs. There was a problem. Further, in the non-aqueous pigment ink, it is difficult to provide a sufficient fixing property, for example, the pigment applied on the inkjet recording medium is easily dropped off by slight friction.

[0010]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention An object of the present invention is to provide an ink jet recording medium having a glossy surface, which is used for ink jet recording using a non-aqueous pigment ink, and has the density, fineness and fixability of a coloring agent of a recorded image. In view of the above, it is to provide an extremely excellent inkjet recording medium.

[0011]

The inventors of the present invention have investigated various configurations of non-aqueous pigment inks and ink jet recording media in order to solve such problems, and by using the following configurations, the present invention It has become possible to provide an inkjet recording medium which has a high density and a high definition of a recorded image and a high fixing property of a colorant, which is a problem of the above.

That is, in an ink jet recording medium for ink jet recording using a non-aqueous pigment ink containing a coloring material pigment, a high boiling solvent and a resin composition soluble in the high boiling solvent, at least one layer is formed on a support. Coating layer, the coating layer contains inorganic ultrafine particles having an average particle size of 100 nm or less, and has a pore radius distribution peak of 2 to
An inkjet recording medium having a thickness of 60 nm is provided.

Here, it is preferable that the resin composition powder is a copolymer obtained by polymerizing at least a monomer represented by the following general formula (1) and a monomer represented by the general formula (2).

[0014]

[Chemical 3]

In the general formula (1), X ¹ represents a hydrogen atom or an alkyl group, and the linking group T is --COO--, --OCO--,-.
CONH- or represents -O-, R ¹ is 8 carbon atoms
It represents a straight-chain alkyl group or a branched alkyl group of 30.

[0016]

[Chemical 4]

In the general formula (2), X ² represents a hydrogen atom or an alkyl group, and R ² represents an alkyl group having 6 to 20 carbon atoms and having a cyclic portion.

Further, the glass transition temperature (T
g) is preferably 30 to 80 ° C.

Further, it is preferable that the inorganic ultrafine particles are at least one selected from vapor-phase process silica fine particles and alumina compounds.

Further, it is preferable that the ink jet recording medium has a peak value of the pore radius distribution at 5 to 30 nm.

Furthermore, the surface of the ink jet recording medium is
The 75 degree glossiness specified in JIS Z8741 is 50
% Or more is preferable.

Further, the Bristow absorption coefficient of the coloring liquid using the high boiling point solvent of the ink jet recording medium is
It is preferably 20 ml / m ² · sec ^1/2 or more.

In addition, the average particle size of the coloring material pigment is 30 to 30.
It is preferably 300 nm.

[0024]

Various materials can be used as the support of the ink jet recording medium in the present invention. For example, polyethylene terephthalate film, polyethylene terephthalate film, polycarbonate film, polypropylene film, various transparent and opaque plastic films such as polyethylene film, aluminum foil, various metal foils such as tin foil,
A fibrous material such as paper, cloth and non-woven fabric can be used as a support for the inkjet recording medium of the present invention.

A sheet in which different kinds of materials are laminated, such as polyethylene-coated paper or a metal vapor-deposited plastic film such as a film obtained by vapor-depositing aluminum on polyethylene terephthalate, is also used as a support for the ink jet recording medium for the water-insoluble ink of the present invention. be able to.

The ink jet recording medium of the present invention has at least one coating layer on the support, and the recording medium surface has gloss.

The coating layer has an average particle size of at least 100 nm.
It contains the following inorganic ultrafine particles and, if necessary, an adhesive. When the average particle size of the inorganic ultrafine particles is larger than 100 nm, sufficient surface gloss cannot be obtained, and the effect of the present invention is difficult to obtain.

When the inorganic ultrafine particles used in the present invention are aggregated with fine particles having an average particle diameter of 100 nm or less to form secondary aggregated particles, it is preferable to use those having an average secondary particle diameter of 400 nm or less. . When the average secondary particle size of the inorganic ultrafine particles is larger than 400 nm, sufficient surface gloss cannot be obtained, and the effect of the present invention is difficult to obtain.

The average particle diameter and the average secondary particle diameter of the inorganic ultrafine particles can be easily examined by observing with an electron microscope or a particle size distribution measuring device.

Examples of such inorganic ultrafine particles include, for example, JP-A-1-97678 and JP-A-2-275510.
Publication No. 3-281383 Publication No. 3-28581
No. 4, JP-A No. 3-285815, and No. 4-92218.
No. 3, gazette 4-267180, gazette 4-2759.
Pseudo-boehmite sol, which is an alumina hydrate disclosed in Japanese Patent Laid-Open No. 17-217, JP-A-60-219083,
No. 61-19389, No. 61-188183, No. 63-178074, and JP-A-5-5147.
No. 0, etc., colloidal silica, JP-B-4-19037, JP-A-62-286787, silica / alumina hybrid sol, JP-A-10-119423, JP-A-10-119423. -2
No. 17601, silica sol in which vapor phase silica is dispersed by a high-speed homogenizer, and other smectite clays such as hectite and montmorillonite.
(JP-A-7-81210), zirconia sol, chromia sol, yttria sol, ceria sol, iron oxide sol,
Typical examples thereof include zircon sol and antimony oxide sol.

Among these inorganic ultrafine particles, vapor-phase method silica fine particles and alumina compounds (alumina hydrate or aluminum oxide fine particles) are particularly preferable.

The silica fine particles are SiO ₂ 93 on a dry basis.
%, Al ₂ O ₃ about 5% or less, Na ₂ O about 5% or less, so-called white carbon,
There are amorphous silicas such as silica gel and finely divided silica.
As a method for producing amorphous silica fine particles, there are a liquid phase method, a pulverized solid phase method, a crystallization solid phase method and a vapor phase method. What is the liquid phase method?
This is a method for producing fine particles in which a so-called silicic acid compound or the like existing in a liquid is precipitated in a solid state by a chemical change or a physical change. The crushing solid phase method is a method of mechanically crushing silica solid, and the crystallization solid phase method is a method of producing fine particles utilizing melting or phase transition of solid. The vapor phase method is a method for producing fine particles by thermal decomposition of vapor of a volatile metal compound, heating and evaporation of raw materials, cooling of generated vapor phase species, and condensation.

Preferred silica fine particles for the present invention are the amorphous silica fine particles synthesized by the vapor phase method among the above. Aerosil (manufactured by Tegusa) can be used as a commercially available product as the amorphous silica fine particles synthesized by the vapor phase method.

Alumina hydrate has the general formula Al ₂ O ₃ .nH
It can be represented by ₂ O. Alumina hydrate is classified into gypsite, vialite, norstrandite, boehmite, boehmite gel (pseudo-boehmite), diaspore, amorphous amorphous and the like depending on the composition and crystal form. In particular, in the above formula, when the value of n is 1, it represents a boehmite structure alumina hydrate, and when n is more than 1 and less than 3, it represents a pseudo-boehmite structure alumina hydrate, and n is A value of 3 or more represents an alumina hydrate having an amorphous structure. Particularly, the alumina hydrate preferred in the present invention has n of 1
It is an alumina hydrate having a pseudo-boehmite structure of more than 3 and less than 3.

The shape of the alumina hydrate used in the present invention may be any of tabular, fibrous, acicular, spherical, rod-like and the like, and the preferable shape is tabular from the viewpoint of ink absorbability. Flat alumina hydrate has an average aspect ratio of 3
The average aspect ratio is 3 to 6. Aspect ratio is "diameter" of "thickness" of particles
It is expressed by the ratio of. Here, the particle diameter means the diameter of a circle that is equal to the projected area of the particle when observing the alumina hydrate with an electron microscope. When the aspect ratio is smaller than 3, the pore size distribution of the ink receiving layer becomes narrow, and the ink absorbability is lowered. On the other hand, if the aspect ratio exceeds 8,
It becomes difficult to produce an alumina hydrate having a uniform particle size.

The alumina hydrate used in the present invention can be produced by a known method such as hydrolysis of aluminum alkoxide such as aluminum isopropoxide, neutralization of aluminum salt with alkali, hydrolysis of aluminate. . In addition, the physical properties such as the particle size, pore size, pore volume, and specific surface area of the alumina hydrate should be controlled by the conditions such as precipitation temperature, aging temperature, aging time, liquid pH, liquid concentration, and coexisting compounds. You can

A method for obtaining alumina hydrate from alkoxide is disclosed in JP-A-57-88074 and JP-A-62-88074.
56321, JP-A-4-275917, 6-64918, 7-10535 and 7
-267633, U.S. Pat. No. 2,656,321
It is disclosed as a method for hydrolyzing aluminum alkoxide in the specification. Examples of these aluminum alkoxides include isopropoxide and 2-butoxide.

Further, Japanese Patent Laid-Open No. 54-116398,
No. 55-23034, No. 55-27824, and No. 56-120508 disclose methods of using an inorganic salt of aluminum or a hydrate thereof as a raw material. Examples of the raw material include inorganic salts such as aluminum chloride, aluminum nitrate, aluminum sulfate, polyaluminum chloride, ammonium alum, sodium aluminate, potassium aluminate and aluminum hydroxide, and hydrates thereof.

Still another method is disclosed in JP-A-56-120.
No. 508, a method of alternately varying the pH from acidic to basic to grow crystals of alumina hydrate, an inorganic of aluminum described in Japanese Patent Publication No. 4-33728. There is also a method in which alumina hydrate obtained from a salt and alumina obtained by the Bayer method are mixed to rehydrate the alumina.

The ink jet recording medium of the present invention comprises:
Commercially available alumina hydrate can also be preferably used. For example, as the alumina hydrate, cataloid AS-1,
Cataloid AS-2, Cataloid AS-3 (all manufactured by Catalyst Chemical Industry), alumina sol 100, alumina sol 20
0, alumina sol 520 (above, manufactured by Nissan Chemical Industries, Ltd.), M-
200 (above, manufactured by Mizusawa Chemical Industry), aluminum sol 10, aluminum sol 20, aluminum sol 132, aluminum sol 132S,
Aluminum sol SH5, aluminum sol CSA55, aluminum sol SV102, aluminum sol SB52 (above, Kawaken Fine Chemicals make) etc. can be mentioned.

As the aluminum oxide (alumina) fine particles used in the present invention, γ-type alumina fine particles which are γ-type crystals are preferably used. Crystallographically classifying γ-type crystals can be further divided into γ group and δ group. Fine particles having a crystal form in the δ group are preferred.

Γ-type alumina fine particles are commercially available as δ
Aluminum oxide C belonging to the group (Japan Aerosil
KKP-G015 (manufactured by Sumitomo Chemical Co., Ltd.) and the like belonging to the γ group.

A water-soluble or water-insoluble polymer compound may be added as an adhesive to the coating layer in the present invention. Examples of the polymer compound used in the present invention include, as water-soluble polymer compounds, cellulose-based adhesives such as methylcellulose, methylhydroxyethylcellulose, methylhydroxypropylcellulose, and hydroxyethylcellulose, starch and its modified products, gelatin and its modified products. Polymer, natural polymer resins such as casein, pullulan, gum arabic, and albumin or their derivatives, polyvinyl alcohol and its modified products, styrene-butadiene copolymer, styrene-acryl copolymer, methyl methacrylate-butadiene copolymer Latex and emulsions such as ethylene-vinyl acetate copolymer, vinyl polymers such as polyacrylamide and polyvinylpyrrolidone, polyethyleneimine, polypropylene glycol,
Examples thereof include polyethylene glycol, maleic anhydride or a copolymer thereof. Preferred is polyvinyl alcohol.

As the water-insoluble polymer compound, an alcohol such as ethanol or 2-propanol or a water-insoluble adhesive soluble in a mixed solvent of these alcohols and water stabilizes the dispersion of alumina. Therefore, it is particularly preferable. Examples of such water-insoluble adhesives include acetal resins such as vinylpyrrolidone / vinyl acetate copolymer, polyvinyl butyral, and polyvinyl formal, and the degree of acetalization is particularly in the range of 5 mol% to 20 mol%. The acetal resin is particularly preferable because it can contain some water and can facilitate dispersion of the inorganic ultrafine particles.

These polymer compounds may be used alone or in combination of two or more, and are 2% by mass or more and 5% by mass or more with respect to the inorganic ultrafine particles.
Add 0 mass% or less. Preferably 5 mass% or more 3
Add 0 mass% or less. If the above-mentioned addition amount is less than 2% by mass, the coating film strength will be weakened, and if it is added in excess of 50% by mass, the ink solvent absorbability will decrease.

The method for forming the coating layer of the present invention includes:
Various methods can be used. For example, the inorganic ultrafine particle dispersion liquid is applied alone or after being mixed with a suitable binder onto a support, and then simply dried, or after applying the coating composition for the coating layer. While the coating composition is in a wet state, or after being dried and then re-wetted, it is pressed against a mirror surface roll to transfer the shape of the mirror surface to the coating layer, by a so-called casting method. It is possible to form a coating layer of an inkjet recording medium.

The coating amount of the coating layer of the present invention needs to be 5 g / m ² or more in terms of solid content, preferably 10 g / m ² or more 35
It is g / m ² or less, and the thickness is preferably 10 μm or more and 50 μm or less.

If necessary, the ink jet recording medium of the present invention may be provided with a layer other than the coating layer, for example, an anchor coat layer for improving the adhesion between the coating layer and the support. In addition, an overcoat layer or a backcoat layer can be provided for the purpose of protecting the coating layer, improving the transportability in the printer, and suppressing curling that occurs after printing.

The ink jet recording medium of the present invention preferably has a 75 degree glossiness defined by JIS Z8741 of 50% or more, more preferably 60% or more, according to JIS Z8741.

The non-aqueous pigment ink used in the present invention contains a coloring material pigment, a high boiling point solvent and a resin composition, and if necessary, a dispersant, a penetrating agent, a low boiling point solvent, an antioxidant and an ultraviolet absorbing agent. Agents and the like can be contained.

Specific examples of the coloring material pigment in the non-aqueous pigment ink of the present invention include Farnest Black,
Lamp black, acetylene black, channel black, C.I. I. Pigment Black, Orthoaniline Black, Toluidine Orange, Permanent Carmine F
B, First Yellow AAA, Disazo Orange PM
P, lake red C, brilliant carmine 6B, phthalocyanine blue, quinacridone red, C.I. I. Pigment Blue, C.I. I. Pigment Red, C.I. I. Pigment Yellow, Dioxane Violet, Pictoria Pure Blue, Alkali Blue Toner, Alkali Blue R Toner, First Yellow 10G, Ortho Nitroaniline Orange, Toluidine Red, Barium Red 2B, Calcium Red 2B, Pigment Scar Red 3B Lake, Anthocin 3B Lake, Rhodamine 6B Lake, Methyl Violet Lake, Basic Blue 6
B lake, fast sky blue, reflex blue G, brilliant green lake, phthalocyanine green G, navy blue, ultramarine blue, iron oxide powder, zinc white, calcium carbonate, clay, barium sulfate, alumina white, aluminum powder, daylight fluorescent pigment, Examples include pearl pigments.

The coloring material pigment is obtained by making the pigment into fine particles and having an integrated particle size 50% value (average particle size) of 30 to 30 by the laser light scattering method.
It is preferable that the 0% and 99% value (maximum particle size) be 500 nm or less. The average dispersed particle size of the finely divided pigment is 30
If it is less than nm, the light resistance is reduced due to the smaller particle size, and the 50% value exceeds 300 nm or the 99% value is 5%.
If it exceeds 00 nm, the color development of the printed part may deteriorate,
In printing on a transparent substrate, it becomes difficult to maintain the transparency of the printed portion, and the precipitation of the pigment in the ink easily occurs.

The colorant pigment is added to the non-aqueous pigment ink in an amount of 3 to 1 in order to obtain a sufficient density (and sufficient light fastness) of the recorded matter.
It is preferably contained in an amount of 5% by mass.

The high boiling point solvent in the non-aqueous pigment ink of the present invention has a boiling point of 120 to 400 ° C., preferably 120 to 400 ° C.
The solvent at 350 ° C. serves as a stable dispersion medium for the finely divided pigment, and functions to prevent the ink from sticking to the nozzle tip of the print head. Therefore, it is preferable to prevent the ink from drying at room temperature, have a high penetration speed with respect to the recording medium, and have a flow characteristic that follows a high-speed ejection print head. The high boiling point solvent is preferably contained in the non-aqueous pigment ink in an amount of 55 to 94 mass%.

Examples of the high boiling point solvent include aliphatic hydrocarbon solvents, carbitol solvents, cellosolve solvents, higher fatty acid ester solvents, higher alcohol solvents, higher fatty acid solvents, aromatic hydrocarbon solvents and the like. To be Among them, liquid paraffin and aliphatic hydrocarbon solvents are suitable because they have little odor.

Examples of the aliphatic hydrocarbon solvent include IP solvent manufactured by Nippon Oil Co., Ltd., Shellsol D40 manufactured by Shell Chemical Co., Ltd.
Shersol D70, Shersol 70, Shersol 71, Isopar E, Isopar G, Isopar H, Isopar L, Isopar M, Exol D30, Exol D40, Exol D80, Exol D110, Exol D130, Exol D14
0, Exol DSP100 / 140 and the like.

Further, butyl carbitol can be used as the carbitol solvent, and ethyl cellosolve can be used as the cellosolve solvent. Examples of the higher fatty acid ester-based solvent include dioctyl phthalate, dibutyl succinic acid isobutyl ester, adipic acid isobutyl ester, dibutyl sebacate, di-2-ethylhexyl sebacate, and the like.
Methyl hexanol, oleyl alcohol, trimethyl hexanol, trimethyl butanol, tetramethyl nonanol, 2-pentyl nonanol, 2-nonyl nonanol, 2-hexyl decanol, etc. are mentioned. Further, examples of the higher fatty acid-based solvent include oleic acid,
Examples of the aromatic hydrocarbon solvent include diisopropyl naphthalene.

These solvents can be used alone, but in order to adjust the viscosity, adjust the penetration into the recording medium, and adjust the wettability with the ink contact part of the print head and printer, You may use the method of using a group hydrocarbon hydrocarbon solvent and a polar solvent together.

Examples of the polar organic solvent include alcohols, particularly long-chain alcohols, glycols, polyglycols, esters and ethers of glycols and polyglycols, particularly mono- and di-alkyl ethers of glycols and polyglycols, ketones and the like. . Further, esters of dicarboxylic acids, for example, dioctyl sebacate ester and the like can be mentioned.

The resin composition soluble in the high-boiling point solvent in the present invention means one which forms a homogeneous phase by mixing with the high-boiling point solvent at an arbitrary ratio at room temperature. Coalescence can be used. As an example, poly (1,3-diene), such as polybutadiene polyisoprene, alkyl (C ₄ or higher) ether, poly alkyl (C ₄ or higher) vinyl carboxylic acid, polyalkyl (C ₄
Or more) (meth) acrylate, polyalkyl (C ₆ or more) (meth) acrylamide, polyoxyalkylene (C ₄ or more),
Polymers such as polydimethylsiloxane, petroleum resins (C ₅ type, C ₉ type), novolac resins, and gutta percha, and copolymers composed of monomers constituting these polymers are used as the high boiling point solvent in the present invention. It can be used as a soluble resin composition.

Of these, a copolymer obtained by polymerizing the monomer represented by the general formula (1) and the monomer represented by the general formula (2) is preferable.

As the monomer represented by the general formula (1),
For example, esters of unsaturated carboxylic acids such as acrylic acid and methacrylic acid substituted with an alkyl group having 8 to 30 carbon atoms (as the alkyl group portion, for example, n-octyl group, 2-ethylhexyl group, decyl group, dodecyl group Group, tridecyl group, tetradecyl group, hexadecyl group, octadecyl group, etc.), amides of the above unsaturated carboxylic acids substituted with an alkyl group having 8 to 30 carbon atoms (wherein the alkyl group part is an ester of an unsaturated carboxylic acid) A vinyl ester of a fatty acid having 8 to 30 carbon atoms in the alkyl group portion (as a fatty acid, for example, pelargonic acid, capric acid, lauric acid, myristic acid, stearic acid), or the number of carbon atoms. Vinyl ethers substituted with 8 to 30 alkyl groups (wherein the alkyl group is the one represented by unsaturated carboxylic acid esters) The same can be mentioned.

Among the monomers represented by the general formula (1), 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, lauryl acrylate, lauryl methacrylate,
Stearyl acrylate and stearyl methacrylate are preferred.

As the monomer represented by the general formula (2),
For example, unsaturated carboxylic acid esters such as acrylic acid and methacrylic acid having 6 to 20 carbon atoms and substituted with an alkyl group having a cyclic portion (as the alkyl group portion, for example, cyclohexyl group, cyclopentyl group, cyclooctyl group) Group, isobornyl group, etc.), and cyclohexyl acrylate, cyclohexyl methacrylate, isobornyl acrylate, isobornyl methacrylate and the like are preferable.

Further, for the purpose of improving the dispersibility of the coloring material pigment and the fixing property with the ink jet recording medium, it is possible to add other vinyl-based monomers as necessary to prepare a copolymer. .

The glass transition temperature (Tg) of the resin composition is 30.
It is preferably -80 ° C. If the Tg is less than 30 ° C, problems such as tackiness due to plasticization of the resin composition due to body temperature are likely to occur when the printed portion is touched by hand, and the Tg is reduced. 80 ° C
If it exceeds the range, the resin composition becomes brittle and easily cracked, and problems such as deterioration of fixability of a printed portion are likely to occur.

The glass transition temperature of the copolymer, which is the resin composition of the present invention, is the glass transition temperature (P
OLYMER HANDBOOK THIRD EDITION (JHON WILEY & SONS 1
989), VI, P209 to 278), and can be calculated by the FOX formula (Introduction to Polymer Chemistry, 2nd edition, P172 1981).

The resin composition has an average molecular weight of 3,000 to
It is preferably 100,000. When the average molecular weight is less than 3,000, sufficient fixability of the printed portion cannot be obtained, and when the average molecular weight exceeds 100,000,
The viscosity of the ink becomes too high, and ejection from the print head becomes difficult.

The resin composition is preferably contained in the non-aqueous pigment ink in an amount of 3 to 30% by mass as a solid content in order to obtain sufficient fixability of the recorded matter.

As the dispersant in the non-aqueous pigment ink of the present invention, a hydroxyl group-containing carboxylic acid ester, a salt of a long chain polyaminoamide and a high molecular weight acid ester, a salt of a high molecular weight polycarboxylic acid, a long chain polyaminoamide and a polar acid ester. Salt, high molecular weight unsaturated acid ester, high molecular copolymer, modified polyurethane, modified polyacrylate, polyether-ester type anionic activator, naphthalenesulfonic acid formalin condensate salt, aromatic sulfonic acid formalin condensate salt, Polyoxyethylene alkyl phosphate ester, polyoxyethylene nonylphenyl ether, stearylamine acetate and the like can be used.

The non-aqueous pigment ink of the present invention has, for example, a linseed oil-modified alkyd resin, polystyrene, rosin-based resin for the purpose of improving its storage stability and adjusting the spread of ink dots on a recording medium. Resins, terpene phenolic resins, polar resins such as alkylphenol-modified xylene resins, metal sequestering agents, surface tension modifiers, surfactants, viscosity modifiers, defoamers, foam suppressors, release agents, foaming Additives such as agents, penetrants, optical brighteners, ultraviolet absorbers, preservatives, water-proofing agents, rheology modifiers and antioxidants may be contained in appropriate combination.

The coating layer in the ink jet recording medium of the present invention has a pore radius distribution peak at 2 to 60 nm, more preferably 5 to 30 nm. When inkjet recording is performed on the inkjet recording medium having this property using the non-aqueous pigment ink, the solvent in the ink is absorbed in the coating layer, and the surface of the coating layer is apparently dry immediately after recording. Become. On the other hand, the coloring material pigment and the resin dispersion are adhered to the surface of the coating layer, and are fixed together with the coloring material pigment when the resin dispersion is dried. A recorded image with high density and high definition can be obtained.

When the peak value of the pore radius distribution of the coating layer is less than 2 nm, the ink solvent absorbency tends to deteriorate,
When it is larger than nm, the coloring material pigment does not stay on the surface of the coating layer and easily penetrates into the coating layer, and thus the effect of the present invention is difficult to obtain.

The measurement of the pore radius distribution referred to in the present invention is performed by MERC.
URY PRESSUER POROSIMETER MOD 220 (manufactured by Carlo.Erba), the void volume distribution curve obtained by the so-called mercury injection method
(`` Surface '' 13 (10), P588 (1975), Paper and Paper Cooperative Paper 28,99 (1974))
From this, the pore radius distribution (differential curve) can be calculated and obtained.

The coating layer of the ink jet recording medium of the present invention has a Bristow absorption coefficient of 20 ml / m ² · sec ^1/2 due to a coloring liquid using a high boiling point solvent which is an ink solvent.
The above is preferable. When ink jet recording is performed on the ink jet recording medium having this property using the non-aqueous pigment ink, the solvent in the ink is quickly absorbed in the coating layer, so that the effect of the present invention is further obtained. Cheap.

The Bristow absorption coefficient referred to in the present invention is
JAPAN TAPPI Paper Pulp Test Method No. 51,
Absorption coefficient Ka specified in the liquid absorption test method for paper and paperboard (Bristow method). For details, refer to “Measurement Method of Liquid Penetration in a Short Time: About Bristow Method” (Paper Paper Co., Ltd. 41,
8, P33). In the present invention, as the test liquid,
A non-aqueous solvent coloring liquid was used. The test liquid was 80 parts of a high boiling solvent, 20 parts of oleyl alcohol, a dye (Fat Red 7
B) A non-aqueous coloring liquid similar to the solvent used in the non-aqueous pigment ink prepared from 0.1 part. The dye is added to check the test results. By investigating the Bristow absorption coefficient by this measuring method, the absorption behavior for the solvent used for the non-aqueous pigment ink in the inkjet recording medium can be analogized.

[0077]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited thereto. In this example, unless otherwise specified, parts and% represent parts by mass and% by mass, respectively.

<Preparation of Inkjet Recording Medium> Recording Medium Example 1 LBKP 80 parts, NBKP 20 parts, light calcium carbonate 8 parts, heavy calcium carbonate 8 parts, talc 8 parts, alkyl ketene dimer 0.1 part, cationic polyacrylamide 0 0.03 part, 0.8 parts of cationized starch, 0.4 part of sulfuric acid band and an appropriate amount of water were mixed to form a slurry, and a support having a basis weight of 90 g / m ² was prepared using a Fourdrinier paper machine. .

While stirring 580 parts of water, silica sol
(Solid content 20%; Snowtex-O manufactured by Nissan Chemical Industries) 1
50 parts, synthetic amorphous silica (Mizukasil P78F manufactured by Mizusawa Chemical Industry Co., Ltd.) 100 parts, fluorescent whitening agent (solid content 50%; Keicor BBL manufactured by Nippon Soda) 2 parts, polyvinyl alcohol (polymerization degree about 1700, saponification degree 98-) 99%; 250 parts of a 10% aqueous solution of Kuraray Poval PVA-117 manufactured by Kuraray, dimethylamine-epichlorohydrin condensate (solid content 50)
%; Yokkaichi Gosei Kathio Master PD-10) (50 parts) was sequentially compounded to prepare a coating liquid. On the support made above,
The coating amount after drying this coating liquid using a wire bar is 10
It was applied so as to be g / m ² and dried with a hot air dryer at 120 ° C. to prepare an ink absorbing layer.

While stirring 285.5 parts of water, 250 parts of silica sol having an average particle size of 40 nm (solid content concentration of 40%; Snowtex XL manufactured by Nissan Chemical Industries, Ltd.) and styrene-butadiene latex (solid content concentration of 48%; Japan) Synthetic rubber J
SR-0691) (62.5 parts) and potassium oleate (2 parts) were sequentially mixed to prepare a coating liquid. On the above-mentioned ink absorbing layer, this coating liquid was applied using a wire bar so that the coating amount after drying was 10 g / m ^2, and was pressed into a mirror-finished roll having a surface temperature of 110 ° C. to be dried, An inkjet recording medium of Recording Medium Example 1 was produced.

Recording medium example 2 Instead of 250 parts of Snowtex XL, an average particle size of 30
Recording Medium Example 1 except that 250 parts of 0 nm silica sol (solid content concentration 40%; Nissan Chemical Industries MP-3040) was used.
An inkjet recording medium was prepared in the same manner as in Example 1 to prepare an inkjet recording medium of Recording Medium Example 2.

Recording medium example 3 LBKP 100 parts, cationized starch 10 parts, polyacrylamide 0.2 parts, alkyl ketene dimer 0.5
Part, polyamide epichlorohydrin 0.5 part, and an appropriate amount of water were mixed to form a slurry, and a base paper having a basis weight of 80 g / m ² was prepared using a Fourdrinier paper machine.

Next, polyvinyl alcohol (Kuraray P
VA110) 2 parts, fluorescent dye (Nippon Soda's K-Call BU)
L) 0.2 part, conductive agent (Chemistat 61 manufactured by Sanyo Kasei Co., Ltd.
20) One part was dissolved in an appropriate amount of water, and the above base paper was impregnated using a size press device so that the impregnated amount after drying was 2.0 g / m ² .

Next, the back surface of the impregnated paper was subjected to corona discharge treatment, and then a mixture of 30 parts of low-density polyethylene and 70 parts of high-density polyethylene was applied by a melt extrusion coating method to form a back-side polyethylene having a thickness of 20 μm. A coating layer was provided.

Subsequently, after corona discharge treatment was applied to the surface, 30 parts of low-density polyethylene and 6 parts of high-density polyethylene were used.
A mixture of 0 part, 9.5 parts of anatase-type titanium dioxide surface-treated with hydrous aluminum oxide and 0.5 part of zinc stearate was applied by a melt extrusion coating method to give a thickness of 2
A surface polyethylene coating layer having a thickness of 0 μm was provided to serve as a support for the inkjet recording medium.

90 parts of silica fine particles (Aerosil 200 manufactured by Nippon Aerosil Co., Ltd.) having an average particle diameter of 20 nm obtained by a vapor phase method are used.
Dispersed in 0 part of ion-exchanged water with a stirrer,
230 parts of an aqueous solution of polyvinyl alcohol (PVA235 manufactured by Kuraray), 10 parts of a cationic polymer (Polyfix P601 manufactured by Showa High Polymer), and 5 parts of boric acid were mixed to prepare a coating liquid. Coating the prepared coating liquid on the surface of the support with a wire bar so that the coating amount after drying is 20 g / m ² .
An ink jet recording medium of Recording Medium Example 3 was produced by drying.

Recording medium example 4 1200 parts of ion-exchanged water, isopropyl alcohol 90
0 part was charged into a 3 L reactor and heated to 75 ° C. Add 408 parts of aluminum isopropoxide and add 2 at 75 ° C.
Hydrolysis was carried out for 4 hours and subsequently at 95 ° C. for 10 hours. After hydrolysis, 24 parts of acetic acid was added and stirred at 95 ° C. for 48 hours.
Next, the mixture was concentrated to a solid content concentration of 15% to obtain a white fine particle alumina hydrate dispersion liquid. When this sol was dried at room temperature and measured by X-ray diffraction, it showed a pseudo-boehmite structure. The average particle size was measured by a transmission electron microscope to find that it was 30 nm, and it was a flat particulate alumina hydrate having an aspect ratio of 6.0.

Using 15% of the ultrafine-particulate alumina hydrate dispersion described above, 15 parts of a 10% aqueous solution of polyvinyl alcohol (PVA105: manufactured by Kuraray) was mixed with 100 parts of the alumina hydrate dispersion. . After mixing, the mixture was homogenized with a homomixer at 10,000 rpm for 10 minutes to obtain a coating liquid. The prepared coating liquid was applied to the same support as in Recording Medium Example 3 using a wire bar so that the coating amount after drying was 20 g / m ^2, and dried to prepare an inkjet recording medium of Recording Medium Example 4. did.

Recording medium example 5 γ-group alumina crystal powder of δ group having an average particle size of 13 nm
(Nippon Aerosil made Aerosil aluminum oxide C) 30
0 g was dispersed in 1700 g of ion-exchanged water with a stirrer to prepare a 15% by mass slurry-like viscous liquid. Using this 15 mass% γ-type alumina dispersion, 20 parts of a 10 mass% aqueous solution of polyvinyl alcohol (PVA235 manufactured by Kuraray) was mixed with 100 parts of the alumina dispersion. After mixing, the mixture was homogenized with a homomixer at 10,000 rpm for 10 minutes to obtain a coating liquid. The prepared coating liquid was applied to the same support as in Recording Medium Example 3 using a wire bar so that the coating amount after drying was 20 g / m ^2, and dried to produce an inkjet recording medium of Recording Medium Example 5. did.

The peak value of the pore radius distribution of each ink jet recording medium is MERCURY PRESSUER POROSIMETER MOD 220.
(Manufactured by Carlo.Erba), the pore size distribution (differential curve) was calculated from the void volume distribution curve obtained by the mercury intrusion method, and the peak due to the coating layer (excluding the peak due to the support, etc. .) Was calculated. The results are shown in Table 1.

The surface gloss of 75 degrees of each ink jet recording medium is determined according to JIS Z8741 with an incident / reflection angle of 7
5 degree is a variable angle gloss meter (VGS-1 manufactured by Nippon Denshoku Industries Co., Ltd.
001 DP). The results are shown in Table 1.

The Bristow absorption coefficient of each ink jet recording medium was determined by using a high boiling point solvent (Exol D1
10) 80 parts, 20 parts of oleyl alcohol, dye (Fat Re
d 7B) Using a non-aqueous coloring liquid similar to the non-aqueous ink prepared from 0.1 part, JAPAN TAPPI Paper Pulp Test Method No. 51
The absorption coefficient Ka was obtained by the (Bristow method). The results are shown in Table 1.

[0093]

[Table 1]

<Synthesis of Resin Composition> Resin Composition Example 1 In a four-necked flask equipped with a stirrer, a thermometer, a nitrogen introducing tube and a reflux cooling tube, 2 as the monomer of the general formula (1) was used.
-Ethylhexyl methacrylate 45 parts, general formula (2)
Cyclohexyl methacrylate 55 as a monomer of
Parts, 1.0 part of azobisisobutyronitrile and 150 parts of IP solvent are added, heated and reacted at 90 ° C. for 3 hours, a polymer having a Tg of about 35 ° C. and a molecular weight of about 25,000 and soluble in the IP solvent. A solution having a nonvolatile content of 40% was obtained.

Resin Composition Examples 2 to 11 Polymerization was performed in the same manner as in Resin Composition Example 1 except that the monomers (type and amount) shown in Table 2 below were used, and the IP solvent having the Tg and the molecular weight shown in Table 2 was used. A 40% nonvolatile solution of a polymer soluble in water was obtained.

[0096]

[Table 2]

<Abbreviation of Monomer> 2-EHA: 2-ethylhexyl acrylate 2-EHMA: 2-ethylhexyl methacrylate LA: Lauryl acrylate LMA: Lauryl methacrylate SMA: stearyl methacrylate The above monomers correspond to the general formula (1). CHMA: cyclohexyl methacrylate IBXA: Isobornyl acrylate IBXMA: isobornyl methacrylate The above monomers correspond to the general formula (2). t-BMA: t-butyl methacrylate

"Glass transition temperature (Tg)" is calculated by the FOX equation.

"Molecular weight" means gel permeation
A column (Tohso GMH) was attached to a chromatography device, and a dried resin composition was dissolved in tetrahydrofuran at a concentration of 0.2% to obtain a sample, which was measured at a temperature of 20 ° C. and a flow rate of 1 ml / min. Determined by comparison with polystyrene standard sample measurements.

<Preparation of Non-Aqueous Pigment Ink> Ink Example 1 A high-boiling solvent (Exol D110) 50 was placed in a sand mill.
Parts, 30 parts of carbon black, and 20 parts of a polyesteramine-based dispersant were added and dispersed for 3 hours.

In a container, 30 parts of the above dispersion liquid, Exol D
33 parts of 110 and 12 parts of oleyl alcohol were added,
Mix for 30 minutes with a stirrer. The average particle diameter of the color material pigment particles in this dispersion mixture was 75 nm, and the maximum particle diameter was 380 nm. Further, 25 parts of Resin Composition Example 1 was added and mixed for 30 minutes to obtain a non-aqueous pigment ink of Ink Example 1.

The particle size of the coloring material pigment was measured by a particle size distribution meter (Microtrac UPA manufactured by Nikkiso Co., Ltd.) by a laser light scattering method. The results are shown in Table 3. Average particle size: D50 (total particle size 50% value) Maximum particle size: D99 (total particle size 99% value)

Ink Examples 2 to 11 Ink Examples 2 to 1 were prepared in the same manner as Ink 1 except that the resin compositions shown in Table 3 were used in place of Resin Composition Example 1.
A non-aqueous pigment ink of No. 1 was obtained.

[0104]

[Table 3]

Ink Example 12 A non-aqueous pigment ink of Ink Example 12 was obtained in the same manner as in Ink 1 except that 25 parts of IP solvent was used in place of Resin Composition Example 1.

Examples 1 to 42, Comparative Examples 1 to 12 The combinations of inks and recording media shown in Tables 4 to 7 were evaluated by the following evaluation methods. The results are shown in Tables 8-11.

[0107]

[Table 4]

[0108]

[Table 5]

[0109]

[Table 6]

[0110]

[Table 7]

Evaluation Method <Density> The ink of the ink example is dropped on the ink jet recording medium of the recording medium example, and the No. Ink droplets were immediately spread using the wire bar of No. 4, and left to dry at room temperature for 1 hour. After that, the optical density near the center of the ink development portion was measured with an optical densitometer (RD-919 manufactured by Macbeth). The larger this value is, the higher the density is. When the density is 1.5 or more, it is good, and when the value is 1.8 or more, it is very good.

<Fineness> An ink jet recording medium of the example recording medium is held horizontally, and one drop of the ink of the example ink is dropped by using a microsyringe (Hamilton 7101 manufactured by Hamilton) having a volume of 1 μL equipped with a needle having an inner diameter of 0.15 mm. Then, it was left to dry at room temperature for 1 hour. Inspect the surface of the ink drop section with a microscope.
An image observed at (100 times) was analyzed by a LUZEX5000 type image analyzer (manufactured by Nireco) to obtain a shape factor calculated by the following mathematical formula 1. The smaller the shape factor is (closer to 1), the higher the roundness is,
High-definition images with no blurring or omission can be obtained when printed with a printer.

<Ink Absorption Rate> The ink jet recording medium of the recording medium example was tilted at 60 ° and one drop of the ink of the ink example was dropped using the same microsyringe as described above. The maximum diameter in the inclined direction and the maximum diameter in the horizontal direction of the ink dropping portion were measured, and the maximum diameter ratio represented by the following mathematical formula 2 was obtained. A smaller value (closer to 1) means that the ink did not flow down the surface of the recording medium between the time when the ink came into contact with the surface of the recording medium, that is, the faster the absorption of ink. And a uniform image is obtained when printed with a printer.

<Fixability> The surface of the ink spreading portion used for density measurement was strongly rubbed with the index finger five times in one direction, and the state of the ink spreading portion was evaluated. ⊚: There was no change in the ink development area. ◯: A slight change was observed in the ink spread portion, but the colorant did not spread around the original spread portion. Δ: The colorant spread around the developed area, but there was no obvious change in the original density of the developed area. X: The original density of the developed portion was reduced. XX: All the colorant in the developed part was peeled off. Good fixability is indicated by ⊚ or ◯, and Δ does not pose any practical problem.

<Tack> The index finger was strongly pressed against the surface of the ink spread portion used for the density measurement for 10 seconds, and the degree of tackiness when released was evaluated. ⊚: No stickiness. ◯: Slightly sticky. Δ: A little sticky. X: Very sticky. Good tack is indicated by ⊚ to ◯, and Δ is not a problem in practical use.

[0116]

[Number 1] shape factor = (contour length of the ink dropping portion) (area of 4 [pi] × ink dropping portion) ² / (Formula 1)

[0117]

[Equation 2]   Maximum diameter ratio = maximum diameter in tilt direction / maximum diameter in horizontal direction (Equation 2)

[0118]

[Table 8]

[0119]

[Table 9]

[0120]

[Table 10]

[0121]

[Table 11]

As is clear from comparison between Examples 1 to 42 and Comparative Examples 1 to 12, a non-aqueous pigment ink containing a coloring material pigment, a high boiling solvent and a resin composition soluble in the high boiling solvent. In an inkjet recording medium for inkjet recording using, at least one coating layer is coated on a support, and the coating layer contains inorganic ultrafine particles having an average particle size of 100 nm or less, and has a pore radius of Distribution peak 2 to 60
It can be seen that, by having the wavelength of nm, all of the density of the recorded image, the fineness, and the fixability of the colorant are good.

Examples 1 to 7 and Examples 8 to 9, Examples 10 to 16 and Examples 19 to 20, Examples 21 to 29 and Examples 30 to 31, Examples 32 to 40 and Example 41. ~ 4
As is clear from a comparison of 2, the resin composition contained in the non-aqueous pigment ink of the present invention contains at least the monomer represented by the general formula (1) and the monomer represented by the general formula (2). It can be seen that the density and fineness of the recorded image and the fixability of the colorant are further improved by the copolymer obtained by polymerization.

Furthermore, Examples 10 to 16 and Examples 17 to
18, Examples 21 to 27, Examples 28 to 29, and Example 3
2 to 38 and Examples 39 to 40, it is clear that the glass transition temperature (Tg) of the resin composition contained in the non-aqueous pigment ink of the present invention is 30 to 80 ° C. It can be seen that the fixability of the colorant is high and there is no sticky feeling on the printed part.

In addition, Examples 1 to 7 and Examples 10 to 1
As is clear by comparing Nos. 4, 21 to 27 and 32 to 38, the coating layer of the inkjet recording medium of the present invention is
At least 1 selected from gas phase method silica fine particles and alumina compounds as inorganic ultrafine particles having an average particle diameter of 100 nm or less.
It contains seeds, has a pore radius distribution peak at 5 to 30 nm, has a 75 degree gloss of 50% or more, and has a Bristow absorption coefficient of 20 ml / m ² · se by a coloring liquid using a high boiling point solvent.
By being c ^1/2 or more, all of the density of the recorded image, the fineness, the fixing property of the colorant, and the sticky feeling of the printed portion are
It can be seen that it is even better.

[0126]

According to the present invention, it is possible to provide an ink jet recording medium which is extremely excellent in terms of density of recorded image, fineness, fixing property of colorant and the like.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2C056 EA13 FC06                 2H086 BA01 BA15 BA21 BA32 BA33                       BA35 BA41 BA45 BA54 BA55                       BA59 BA60

Claims (8)

[Claims] 1. An inkjet recording medium for inkjet recording using a non-aqueous pigment ink containing a coloring material pigment, a high boiling solvent and a resin composition soluble in the high boiling solvent, and at least one layer or more on a support. Is coated, the coating layer contains inorganic ultrafine particles having an average particle diameter of 100 nm or less, and has a pore radius distribution peak at 2 to 60 nm. Inkjet recording medium. 2. The resin composition has at least the following general formula:
The inkjet recording medium according to claim 1, which is a copolymer obtained by polymerizing the monomer represented by the formula (1) and the monomer represented by the general formula (2). [Chemical 1] (In the general formula (1), X ¹ represents a hydrogen atom or an alkyl group, and the linking group T is —COO—, —OCO—, —CONH—.
Alternatively, it represents —O—, and R ¹ represents a linear alkyl group having 8 to 30 carbon atoms or a branched alkyl group. ) [Chemical 2] (In the general formula (2), X ² represents a hydrogen atom or an alkyl group, and R ² represents an alkyl group having 6 to 20 carbon atoms and having a cyclic portion.) 3. The glass transition temperature (Tg) of the resin composition
Is 30 to 80 ° C. 3. The inkjet recording medium according to claim 1, wherein 4. The ink jet recording medium according to claim 1, wherein the inorganic ultrafine particles are at least one selected from gas phase method silica fine particles and alumina compounds. 5. The peak value of the pore radius distribution is 5 to 30 nm.
The inkjet recording medium according to any one of claims 1 to 4, wherein the inkjet recording medium comprises: 6. A JI of the surface of the ink jet recording medium.
The inkjet recording medium according to any one of claims 1 to 5, wherein the 75-degree glossiness defined by S Z8741 is 50% or more. 7. The Bristow absorption coefficient of the coloring liquid using the high boiling point solvent of the ink jet recording medium is 20.
ml / m ² · sec ^1/2 or more, 7.
The inkjet recording medium according to any one of 1. 8. The average particle diameter of the coloring material pigment is 30 to 300.
The inkjet recording medium according to claim 1, wherein the inkjet recording medium has a thickness of nm.