WO2001089853A1

WO2001089853A1 - Inkjet recording medium

Info

Publication number: WO2001089853A1
Application number: PCT/JP2001/004218
Authority: WO
Inventors: Hidetsugu Oda; Suguru Kashima; Hiroyuki Onishi; Masaya Shibatani; Jun Sugiyama
Original assignee: Mitsubishi Paper Mills Limited; Seiko Epson Corporation
Priority date: 2000-05-22
Filing date: 2001-05-21
Publication date: 2001-11-29

Abstract

An inkjet recording medium for use in recording through delivering droplets of a pigment ink containing a colored pigment, an organic solvent having a high boiling point, a dispersant, a permeation controlling agent and water which has a support and an ink absorbing layer, wherein the ink absorbing layer comprises an inorganic pigment and a polymer adhesive, the inorganic pigment having an oil absorption specified in JIS K5101 of 150 ml/100 g or more and an average secondary particle diameter of 3.0 ν to 15 ν. The inkjet recording medium can has an additional ink absorbing layer on the other surface of the support. The inkjet recording medium has high ink absorption and exhibits good color reproducibility region.

Description

Description Inkjet recording media Technical field

The present invention relates to an ink jet recording medium for recording using a pigment ink. More specifically, the present invention relates to an ink jet recording medium having high ink absorbency and good color reproduction range. Further, the present invention also relates to an ink jet recording medium capable of printing on both sides.

Background art

The ink jet recording system uses a variety of operating principles to fly fine ink droplets and attach them to recording media such as paper to record images, characters, etc.High-speed, low-noise, multi-color recording It is easy to use, has great flexibility in recording patterns, and does not require uniform development. It is rapidly spreading in various applications as a recording device for various graphics including kanji and color images. Furthermore, images formed by the multi-color ink jet method can obtain recorded images comparable to multi-color printing by the plate making method and printing by the color photographic method. Also, in applications where the number of copies required is small, it is being widely applied to the field of full-power image recording because it is cheaper than photographic technology and printing technology.

Efforts have been made from the aspect of the ink composition of the device to use high quality paper—coated paper used for ordinary printing and writing as the recording medium used in the ink jet recording method. However, as the performance of ink jet recording devices such as high-speed and high-definition devices or full-color devices has been improved and their applications have been expanded, more advanced characteristics have been required for recording media. became. That is, as the recording medium, the density of the print dots is high, the color tone is bright and vivid, the ink is quickly absorbed, and the ink does not flow or bleed even when the print dots overlap, The diffusion in the horizontal direction is uniform and not excessively large, and the periphery is smooth and not blurred.The image quality does not change with time or environment.For example, it has excellent light resistance, water resistance, and ozone resistance. Is required. Several proposals have been made in response to such demands. Regarding the improvement of ink absorbency and the prevention of print dot diffusion, a method of providing an ink absorbing layer on a support has been disclosed in JP-A-52-9744 and JP-A-58-72495. However, with respect to color and sharpness, Japanese Patent Application Laid-Open No. 55-144172 discloses a method using a specific additive that adsorbs a dye component in an ink absorbing layer. Further, in order to improve light resistance, water resistance and ozone resistance, Japanese Patent Application Laid-Open No. 60-113389 discloses that a basic oligomer is contained. No. 5 discloses the use of a polybulamine copolymer for a coating layer in or on a substrate. However, while the demands for these characteristics are becoming increasingly sophisticated and strict, ink jet recording devices are inexpensive and can easily produce images with excellent image reproducibility and sharpness and color reproducibility on a personal computer level. With the availability of inkjet recording devices, inkjet recording devices have changed from special recording devices used by specific people to general-purpose recording devices. In addition, since images can easily be obtained in quality comparable to printed matter and photographs, they are also being used as printers for self-made postcards and digital photographs. In this case, the texture and feel of postcards and photographic prints were required. In addition, in such applications, the amount of ink to be ejected is large, and the ink solvent reaching the base paper causes the printed sheet to undulate, thereby causing a problem of poor appearance.

Furthermore, with the diversification of uses, it is used for posters and POP arts, and has a pressure-sensitive adhesive layer on the back side to display price labels, product display (bar code) labels, quality display labels, and weighing displays. It has come to be used for labeling such as advertising labels and advertising labels (stickers). Since these labels adhere well to a wide range of adherends and are easy to apply, they can be attached to a sheet with heat-sensitive properties, magnetic properties, and offset printing suitability via an adhesive layer on the other side. It is also possible to add complex functions. For this reason, applications for applications connected to computers, such as tickets, commuter passes, and various cards, are also expanding.

The form of the ink jet recording medium is a so-called plain paper type typified by so-called high-quality paper and pond paper, and a paper such as high-quality paper; It is roughly classified into a coating type provided with an ink absorbing layer. For the coating type ink jet recording medium, various characteristics of the coated ink absorbing layer directly affect the printing quality.Therefore, regarding the absorptivity, the selection of the specific surface area and shape of the pigment, color saturation, color density, etc. Investigating the transparency and refractive index of pigments, examining the coating layer structure and surface shape for image quality, and examining the improvement of paper undulations, such as elongation in water and blending of synthetic and glass fibers. Various studies have been made on coating methods and the like. In addition, the diversification of uses has also occurred in the appearance of ink jet recording media. In addition to conventional plain paper or matte paper, it has no gloss or low gloss! A glossy appearance similar to paper, cast paper, photographic paper, etc. may be required. This is because there is a demand for the appearance to be similar because the ink jet recorded image can reproduce image quality comparable to printing and photography.

Therefore, as an inkjet recording medium having a glossy surface, a cast coated paper obtained by performing a cast finish while the coating layer is in a wet state is disclosed in JP-A-6-320857 and the like. The surface gloss is extremely low compared to salt photographic paper, and the gloss and texture of silver salt photographs cannot be obtained.

On the other hand, as an ink jet recording medium having improved surface gloss, a medium in which an ink absorbing layer made of a resin is provided on a support has been proposed. Examples of resins used in such applications include polyvinylpyrrolidone, vinylpyrrolidone-vinyl acetate copolymer, as disclosed in JP-A-57-38185 and JP-A-62-184879. JP-A-60-234879, JP-A-60-171143 and JP-A-61-134290 disclose resinous compositions mainly composed of polyvinyl alcohol disclosed in JP-A-60-234879. A copolymer of vinyl alcohol and olefin or of styrene and maleic anhydride, a crosslinked product of polyethylene oxide and isocyanate as disclosed in JP-A-61-74879. A mixture of carboxymethylcellulose and polyethylene oxide as disclosed in JP-A-61-181679; a polyvinyl alcohol as disclosed in JP-A-61-132377. Runime Takuriruami de-grafted polymers, in JP 62-220383 An acryl-based polymer having a carboxyl group as disclosed, a polyvinyl acetal-based polymer as disclosed in JP-A-4-1214382, and the like, and disclosed in JP-A-4-282282 and JP-A-285285. Various ink-absorbing polymers such as a cross-linkable acrylic polymer have been used. In addition, Japanese Patent Application Laid-Open Nos. 4-282282 and 4-285650 disclose an ink jet recording medium using a polymer matrix composed of a crosslinkable polymer and an absorbent polymer in combination. However, compared to a porous ink absorption layer made of fine pigment particles such as silicide, the ink absorption layer made of these resins has a lower surface gloss but has a lower absorption rate and a lower absorption capacity. It has the disadvantage of being small. In recent years, as an ink jet recording medium having a high ink absorption rate and an enhanced surface gloss, a medium using alumina hydrate (cationic alumina hydrate) has been proposed. JP-A 60-245588, JP-B 3-24906, JP-A 6-199035, JP-A 7-82694, and the like support fine quasi-boehmite-type alumina hydrate together with a water-soluble binder. An ink jet recording medium coated on the body surface is disclosed. However, an ink jet recording medium using pseudo-boehmite alumina hydrate has very high surface gloss, but has a small pore volume, and is described in, for example, JP-A-5-24335. As described above, the ink absorption capacity is small, and thick film coating is necessary to obtain a sufficient ink absorption capacity.

For example, Japanese Patent Application Laid-Open No. 10-203006 discloses an ink jet recording medium having a primary particle diameter of 3 nm to 3 Onm and using synthetic silica mainly by a gas phase method. In this case, a film thickness of 30 Aim or more is required to obtain a sufficient absorption capacity.

On the other hand, as proposals for improving absorption, resolution, color density, etc., JP-A-9-195042, JP-B-3-26665, and JP-A-10-297079 disclose specific examples of coating pigments. There is disclosed an ink jet recording medium or a filler for a recording medium, which defines a surface area, a particle diameter, and a uniform number n of rosin-lamellar distribution. On the other hand, attempts have been made to improve light fastness and water fastness from the ink side.Pigments that are superior to dyes in light fastness, water fastness, and gas fastness have recently improved these problems. For this purpose, utilization as an ink composition for ink jet recording has been studied. The advantages of pigment inks are that they have excellent light resistance and water resistance as described above, but they are weaker in abrasion resistance than inks that use dyes as coloring agents, and are used to prevent stains on printed matter. Need to be fixed on a recording medium.

Various studies have been made to solve this problem. Examples of fixing means include a case in which a water-soluble resin is mixed with the ink (Japanese Patent Application Laid-Open Nos. Hei 6-108010 and Hei 6-128486) and the inside of a recording medium. Examples of adding a penetrant for the purpose of penetrating pigment into pigments (JP-A-6-116522, JP-A-4-159072) and a combination of a water-soluble resin and a penetrant Examples (Japanese Unexamined Patent Publication No. Hei 6-135006) include, for example, those with insufficient fixability or with insufficient color density due to excessive penetration. It was not practical. On the other hand, as a result of giving too much consideration to the fixability, the resulting pigment ink was inferior in the original light fastness and gas fastness of the pigment, and this was often a practical problem.

In order to solve these problems, a pigment ink composition for an ink jet is disclosed in WO99Z0530. That is, the cyan ink composition, as a colorant pigment, CI Pigment Blue 15: contains 3 from 2 4 wt ^_0/0, the magenta ink yarn且成comprises a I. Pigment Red 122 as a colorant pigment 3-5 weight includes ^_0/0, Ieroinku composition comprises CI pigment Yellow 128. 3 to 5 wt% as a coloring material顏料, Purakkui ink composition comprises carbon black 2-5% by weight as the color material pigment, orange Inku composition, the I. Pigment Orange 43 or I. Pigment Orange 36, good Mashiku comprises 2-5 wt ^_0/0, green ink composition, a CI Pigment green 7 also properly CI Pigment green 36, preferably Comprises 2-5% by weight.

In addition, these ink compositions, an acetylene glycol compound as a penetrant from 0.1 to 5 weight ⁰ /. Glycerin and ethylene glycol monobutyl ether as high boiling organic solvents in an amount of 2 to 15% by weight, and the water-soluble dispersant is a styrene- (meth) acrylic acid-based water-soluble resin, (Meth) An acrylic acid-based water-soluble resin in a ratio of 0.1 to 1% by weight in terms of solid content is exemplified. By using this ink composition, it became possible to provide a printed matter having good fixability and excellent storage properties such as light fastness and gas fastness. Insufficient performance matching with the recording medium will result in insufficient performance of the ink.Especially when aiming for an image comparable to a silver field photograph, the target must be set in terms of color density, color saturation, color reproduction range, etc. It did not reach to achieve.

As described above, the ink composition technology of the ink jet recording medium is adapted to the ink jet recording technology which has been highly developed in recent years, particularly the ink composition using a coloring material pigment in order to improve light resistance and storage stability. It was not enough to satisfy the requirements for ink absorption, color, and color density.

An object of the present invention is to provide an ink jet recording medium for recording using a pigment ink, which is excellent in ink absorption, coloring material pigment fixability, and color reproduction range (described later). Another object of the present invention is to provide an ink jet recording medium which is excellent in these characteristics and can be printed on both sides.

Disclosure of the invention

The present inventors have intensively pursued an inkjet recording medium that has high ink absorption, colorant / material adhesion, and excellent color reproduction range when recording with pigment ink. It has been found that when recording is performed using a pigment ink containing a specific composition on an ink jet recording medium provided with an ink absorbing layer using a pigment, the above-described problem is satisfied, and it was found that the ink jet recording medium of the present invention was completed. Reached. That is, according to the present invention, the following ink jet recording medium and its use are provided.

(1) An ink jet recording medium for pigment ink, comprising: a support; and an ink absorbing layer provided on one surface of the support, wherein a colorant pigment and a high boiling organic solvent are provided on the ink absorbing layer. In a recording medium for performing recording by discharging droplets of a pigment ink containing a dispersant, a penetrant and water, the ink absorbing layer contains an inorganic pigment and a polymer adhesive, and the inorganic pigment is A recording medium having an oil absorption specified in JISK5101 of at least 150 ml / 100 g and an average secondary particle diameter of at least 3.0 μm and at most 15 μm.

(2) The recording medium according to (1), further comprising, on another surface of the support, an ink absorbing layer specified in (1).

(3) The ink absorbing layer is provided in an amount of 7 g / m ² or more and 20 g / m ² or less, The recording medium of (2).

(4) The recording medium according to (1) or (2), wherein the ink absorbing layer further contains a cationic water-soluble resin.

(5) The recording medium according to (1) or (2), wherein the dispersant for the pigment ink is a styrene- (meth) acrylic acid-based water-soluble resin, and the penetrant is an acetylene glycol compound.

(6) An ink jet recording medium for a pigment ink, comprising a support and an ink absorbing layer, wherein the ink absorbing layer contains an inorganic pigment and a polymer adhesive, and the inorganic pigment is 150 ml / 100. g or more of the oil absorption specified in JISK 5101 and an average secondary particle diameter of 3.0 μm or more and 15 μm or less. Use for recording by ejecting droplets of pigment ink containing solvent, dispersant, penetrant and water.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the inkjet recording medium of the present invention will be described in detail.

Examples of the support that can be used in the present invention include resin films such as polyester films, polyolefin films, polyvinyl chloride, paper such as plain paper, coated paper, and tracing paper, resin-coated paper, synthetic paper, and adhesive paper. An adhesive film or the like is used. There is no particular limitation on the support on which the ink-absorbing layer can be provided, such as glass, ethanol foil, vapor-deposited paper, vapor-deposited film, non-woven fabric, leather products, and ceramic products. The body is most preferred. The inorganic pigment used in the ink absorbing layer in the present invention has an oil absorption of at least 150 ml Zl 00 g and a mean secondary particle diameter of 3.0 determined based on the pigment test method JIS-K5109. It is not less than μm and not more than 15 μm. Preferably, the oil absorption is 200 ml / 100 g or more. As the inorganic pigment, synthetic amorphous silica fine particles, synthetic magnesium carbonate fine particles and the like are preferable, and synthetic amorphous silica fine particles are particularly preferable. The above-mentioned predetermined inorganic pigment is used in the present invention, the coloring material pigment, a high-boiling organic solvent, a dispersant, a penetrant and water in combination with a liquid medium in the pigment ink containing at least water, absorbability, Desired performance such as color saturation and color density can be obtained. When the average secondary particle diameter is less than 3.0 // m, the fixability of the pigment ink is reduced, and a bronzing phenomenon of the black ink occurs. Bronze-dani means that the black color appears brownish, reducing the color density and deteriorating the quality. Also, the average particle size

If it exceeds 15 μm, the color density will decrease. This is thought to be because the coloring material in the ink wraps around the backside of the inorganic pigment particles, concealing the coloring material pigment seen from the surface. In particular, when a penetrant is contained in the ink, the particle size has a significant effect. It is not clear why the oil absorption affects the color reproduction range, etc., but it is presumed to have some effect on the absorption state of the high-boiling organic solvent and penetrant contained in the ink. It is presumed that the combination of the high-boiling organic solvent and the penetrant in the ink used in the present invention favors the oil absorption of the pigment in the ink absorption layer, under conditions.

The amorphous silica force particles preferably used in the present invention, S i O 29 3% or more on a dry basis, A 1 ₂ 0 ₃ to about 5% or less, with microparticles containing N a ₂ 0 to about 5% Yes, there are so-called white carbon, silica gel and amorphous fine powder silica. The method for producing amorphous silica fine particles is roughly classified into a dry method and a wet method. The dry method includes a combustion method and a heating method. In addition, the wet method includes a production method called a precipitation method and a gel method. The dry combustion method is a method in which a mixture of hydrogenated silicon tetrachloride and hydrogen is burned in air at 1600 to 2000 ° C., which is also called a gas phase method. Wet precipitation method usually a silicofluoride sodium and sulfate are reacted in an aqueous solution, S i 0 ₂ in a method of precipitating a specific surface area of the silica according to the conditions of the addition rate of the reaction temperature and the acid (40 to 400 ² / g) and the primary particle size (5-80 nm) can be adjusted. In addition, the secondary particle size ゃ silica physical properties change subtly under drying and milling conditions. The wet gel method is generally produced by reacting sodium silicate and sulfuric acid at the same time, for example.The polymerization of silica particles, such as dehydration condensation of silanol groups, progresses to a three-dimensional hydrogel structure. It is a natural thing. The feature is that since the primary particles have a relatively small hydrogel structure, secondary particles with a large specific surface area can be produced.

By adjusting the size (15 nm) by changing the reaction conditions, secondary particles with different oil absorption can be produced.

As the amorphous silica fine particles, of the above, silica fine particles synthesized by a wet method are preferable, the oil absorption is 150 ml or more, and the average secondary particle diameter is 3. Amorphous silica fine particles of 0 μm or more and 15 μm or less. ,

The polymer adhesive used in the present invention is a water-soluble or water-insoluble polymer compound, and is a compound having an affinity for ink as a component of the ink absorbing layer. Examples of the water-soluble polymer compound include starch derivatives such as starch, oxidized starch, cationized starch, etherified starch, phosphorylated ester starch, carboxymethylcellulose, hydroxymethylinoresenolerose, and hydroxyxe. Cellulose derivatives such as chinoresenolose, cellulose sulfate, etc., various derivatives such as polyvinyl alcohol or silanol-modified products thereof, carboxylated products, force-thione products, etc., casein, gelatin, denatured gelatin, soy protein, etc. Water-soluble synthetic polymers such as natural polymers, polyvinylpyrrolidone, sodium polyacrylate, sodium salt of styrene-maleic anhydride copolymer, and sodium polystyrenesulfonate are used. Also, conjugated copolymer latexes such as styrene-butadiene copolymer and methyl methacrylate-butadiene copolymer, and acrylic polymer latex such as polymers or copolymers of atarylate and methacrylate esters. Vinyl-based polymer latex such as ethylene-vinyl acetate-copolymer, vinyl chloride mono-vinyl acetate copolymer, or a functional group-modified polymer latex with a functional group-containing monomer such as a carboxy group of these various polymers And thermosetting synthetic resins such as polyurethane resin latex, melamine resin and urea resin. Preferably, it is polyvinyl alcohol or a derivative thereof.

Examples of the water-insoluble polymer compound include alcohols such as ethanol and 2-propanol, and water-insoluble binders that are dissolved in a mixed solvent of these alcohols and water. Examples of such non-water-soluble binder, Byurupiro Li Dong // vinyl acetate copolymer, polyvinyl butyral, can be cited Asetaru resin such as polyvinyl formal, especially Asetaru degree is 5 mole ^_0/0 or 2 0 The acetal resin in the range of mol% or less is particularly preferable because it can contain water to some extent and can facilitate dispersion of the amorphous silica fine particles.

These polymer adhesives may be used alone or in combination of two or more, and are used in an amount of 2 to 60% by weight with respect to the inorganic pigment. /. Is added. Preferably, 10 to 50% by weight is added. If the amount is less than the above range, the strength of the coating film becomes weak. The color density decreases.

In the present invention, it is also a preferable embodiment that the ink absorption layer contains a cationic water-soluble resin. Examples of the cationic water-soluble resin used in the present invention include secondary amine, tertiary amine, and quaternary ammonium salts such as polyethyleneimine salts, dimethylamineephalohydrin condensates, polybieramine salts, polyallylamine salts, and polydimethyl salts. Examples include a quaternary ammonium salt methacrylate, a polydiaryldimethylammonium salt, a diarylamineatarylamide copolymer salt, and a quaternary ammonium salt of polystyrene. Above all, quaternary cyclic amines can be cited as ones that lead to more favorable color and color density. There is no problem in blending and using two or more of these cationic resins. Rather, they may be blended aggressively in order to maximize each characteristic.

In these cationic water-soluble resins, the coloring material in the pigment ink is dispersed in the liquid medium by the dispersing agent, and the surface thereof is negatively charged. is there. Therefore, it is considered that the dispersed colorant pigment in the ink is trapped near the surface, and the color reproduction range becomes wider. Further, the smaller the difference in the refractive index from other materials (inorganic pigments and adhesives) used in the ink absorbing layer, the more the light scattering in the ink absorbing layer is reduced. It is thought that the presence of color has improved color saturation and color density, and has helped to broaden the color reproduction range.

The method of applying the coating liquid for forming the ink absorption layer in the present invention includes various coating methods such as E-par coating, curtain coating, strado hopper coating, eta-strusion coating, roll coating, air knife coating, gravure coating, and rod bar coating. Can be adopted.

In the present invention, the layer constitution of the ink absorbing layer may be a single layer or a laminated constitution. In the case of a laminated structure, all layers may be layers having the same composition, or may be a laminated structure with a layer composed of other components.

In the present invention, when an ink absorbing layer is provided on one side of the support, the coating amount of the ink absorbing layer must be 0.5 g or more per unit square meter in terms of solid content. Is preferably not less than 1. O g and not more than 4 ° g per square meter. When an ink absorbing layer is provided on both sides of the support, the coating amount of the ink absorbing layer must be 7 g or more per unit square meter in terms of solid content. 7 g or more and 20 g or less. If the coating amount is less than 7 g Zm ² , the penetrant-containing ink used in the present invention penetrates the base paper layer to reach the back surface, and a phenomenon of strike-through occurs. In order to prevent this, the coating layer contains an inorganic pigment with an oil absorption of 15 Om1 / 100 g or more, and

A coating amount of 7 g / m ² or more is required. Further possible coating amount is large although for these problems is effective, even when applied ² 0 g / m 2 or more effects never change much, lowering the difficulty and the coating layer strength of the coating Therefore, it is not very desirable.

As a means for drying after coating, a general known method can be used, and is not limited. For example, there are a method in which heated air generated by a heat source is conveyed into a heated heater, and a method in which the air is passed near a heat source such as a heater.

Further, the inorganic pigment and the polymer adhesive used in the present invention, preferably further, a coating liquid for forming an ink absorption layer containing a cationic water-soluble polymer, if necessary, a surfactant, Color dyes, color pigments, UV absorbers, antioxidants, pigment dispersants, defoamers, leveling agents, preservatives, fluorescent whitening agents, viscosity stabilizers, pH regulators, hardeners, etc. Various known additives can be added.

The pigment ink referred to in the present invention refers to one that uses a pigment as a coloring material, contains a dispersant and a penetrant, and also contains water, a high-boiling organic solvent, and the like. For example, there is a pigment ink disclosed in W099 / 05230. A low-boiling organic solvent may be used as needed for the pigment ink. The ink containing the penetrant and, if necessary, a low-boiling organic solvent has a strong penetrating power into the recording medium, and is said to be a quick-penetrating ink. The pigment ink is an ink using a pigment as a coloring material, and any pigment may be used, and any of an inorganic pigment and an organic pigment may be used, and there is no particular limitation. For example, the following are mentioned.

As the inorganic pigment, in addition to titanium oxide and iron oxide, carbon black produced by a known method such as a contact method, a furnace method, and a thermal method can be used. Organic pigments include azo dyes (including azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments, etc.), polycyclic pigments (for example, phthalocyanine). Nin pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinatalidone pigments, dioxazine pigments, thioindico pigments, isoindolinone pigments, quinoflurone pigments, etc., dye chelates (eg basic dye chelates, acid dye chelates) Etc.), nitro pigments, nitroso pigments, aniline black and the like can be used.

In particular, as carbon black used as black ink, for example, Mitsubishi Chemical No.2300, No.900, MCF88, No.33, No.40, No.45, No.52, MA7, MA8, MA100, NO.220QB, etc., Colombian: t | R Raven5750, Raven5250, Raven3500, Ravenl255, Raven700, etc., are Cabotnet clay made Regal400R, Regal330R, Regal660R, Mogul L, Monarch 700, Monarch 800, Monarch 880, Monarch 900, Monarch 1000, Monarch 1100, Monarch 1300, Monarch 1400, etc. are manufactured by Tegussa Color Black FW1, Color Black FW2, Color Black FW2V, Color Black FW18, Color Black FW200, Color Black S150, Color Black S160, Color Black S170, Printex 35, Printex U, Printex V, Printex 140U, Special Black 6, Special Black 5, Special Black 4A, Special Black 4, etc. can be used.

Examples of the pigment used in the yellow ink include CI Pigment Yellow 1, CI Pigment Yellow 2, CI Pigment Yellow 3, CI Pigment Yellow 12, CI Pigment Yellow 13, CI Pigment Yellow 14C, CI Pigment Yellow 16, and CI Pigment Yellow 16. 17, CI Pigment Yellow 73, CIPigment Yellow 74, CI Pigment Yellow 75, CI Pigment Yellow 83, CIPigment Yellow 93, CIPigment Yellow 95, CI Pigment Yellow 97, CIPigment Yellow 98, CIPigment Yellow 114, CI Pigment Yellow 128, CI Pigment Yellow 129, CI Pigment Yellow 151, CI Pigment Yellow 154 and the like.

Examples of pigments used in magenta ink include CI Pigment Red 5, CI Pigment Red 7, CI Pigment Red 12, CI Pigment Red 48 (Ca), CI Pigment Red 48 (Mn), and CI Pigment Red 57 (Ca). CI Pigment Red 57: 1, CI Pigment Red 112, CI Pigment Red 122, CI Pigment Red 123, CI Pigment Red 168, CI Pigment Red 184, CI Pigment Red 202 and the like.

Also, as pigments used for cyan ink, CIPigment Blue 1, CI Pigment Blue 2, CI Pigment Blue 3, CI Pigment Blue 15: 3, CI Pigment Blue 15:34, CI Pigment Blue 16, CI Pigment Blue 22, CI Pigment Blue 60, CI Vat Blue 4, CI Vat Blue 60, etc. Is mentioned. A dispersant is used to disperse the pigment. Examples of the dispersant include styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, styrene-methacrylic acid-acrylic acid alkyl ester copolymer, styrene-CK-methylstyrene-acrylic acid copolymer, styrene-acrylic acid copolymer. a-Methylstyrene-acrylic acid-acrylic acid alkyl ester copolymer, sodium polyacrylate, styreneacrylic acid copolymer-ammonium salt, polymer dispersant such as sodium hexamethaphosphate or surfactant Can be mentioned. Preferred is a styrene mono (meth) acrylic acid-based water-soluble resin.

A penetrant is added to control the permeability of the ink into the recording medium. Adione surfactants (sodium dodecylbenzenesulfonate, sodium laurate, ammonium polyoxyethylene alkyl ether sulfate) Salt, etc.), non-ionic surfactants (polyoxyethylene alkyl ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylphenyl ether ether, polyoxyethylene alkylamine, polyoxyethylene alkyl Amide) and acetylene glycol (Olfine Y, Surfynol 82.10.44.40.465.48.55 (all manufactured by Air products and Chemicals Inc.)). Preferred is an acetylene glycol-based penetrant.

High-boiling organic solvents are added to prevent ink clogging and to aid ink permeability. They are water-miscible and water-retaining, and have a low vapor pressure (a vapor pressure of 0.0 The boiling point is preferably from 120 to 250 ° C, the viscosity is from 2 mPa · s to 15 OmPa · s, and the surface tension is 0. .01 to 0.IN Zm are preferably used. Examples thereof include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, and propylene glycol, butylene glycol, 1.2.6—hexanetriol, thioglycol, and so on. Xylene glycol, glycerin, Polyhydric alcohols such as trimethylolmethane and trimethylolpropane, ethylene glycolone monoethylene ether, ethylene glycol monobutylinoleatenoethylene, methylenglyconele monomethinoleatenole, and methylene glycol monoethylene Alkyl ethers of polyhydric alcohols such as ter, triethylene glycol monoethyl ether, triethylene glycol monomethyl ether, urea, 2-pyrrolidone, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidino And triethanolamine are examples.

The low-boiling organic solvents used as necessary include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, tert-butanol, iso-butanol, n-propanol. Pentanol and the like.

In addition, resin emulsion and sugar can be added to the pigment ink. Examples of the resin emulsion include (meth) atallylic acid-based water-soluble resin, butyl acetate-based resin, styrene-butadiene-based resin, butyl chloride-based resin, ataryl-styrene-based resin, butadiene-based resin, styrene-based resin, and crosslinked acrylic-based resin Resin, cross-linked styrene resin, benzoguanamine resin, phenol resin, silicon resin, urethane resin, epoxy resin, etc., and these resins have a structure that has both a hydrophilic part and a hydrophobic part It is desirable that

Sugars include monosaccharides, disaccharides, oligosaccharides, polysaccharides and the like. Specific examples include gnorecose, mannose, funolectose, xylose, arabinose, galactose, aldonic acid, glycissile, sorbitol, maltose, cellobiose, ratatose, sucrose, trenulose, maltotriose, and polysaccharides. , Alginic acid, α-cyclodextrin, cellulose and the like. In addition to the above, ρρ adjusters, preservatives, fungicides, antioxidants, and the like can be included. The feature of the pigment ink used in the present invention is that it contains at least a colorant pigment, a high-boiling organic solvent, a dispersant, a penetrant and water. As the dispersant, a styrene- (meth) acrylic acid-based water-soluble resin is preferable, and as the penetrant, an acetylene glycol compound is preferable. When recorded on the recording medium of the present invention with the pigment ink having this characteristic, the color reproduction range is particularly improved. I'm not sure why, but with dispersants Ren- (meth) acrylic acid-based water-soluble resin and a pigment ink containing an acetylenic alcohol compound as a penetrant, the oil absorption in the recording medium is at least 150 m1Z100 g, and the average particle size is 3 It is considered that there is some influence on the absorption behavior of dispersants and penetrants between pigments with a size of 0 μm or more and 15 μm or less, and that the penetration of colorant pigments is controlled.

The color reproduction range is C (cyan), M (magenta), Y (yellow), R (red, M + Y), G (green, C + Y), B (blue, C + M) depending on the inkjet color printer. ) Is printed in solid color, and the color is measured with a colorimeter (spectrophotometer) to determine the L * a * b * value. The a *, 1> * values are plotted with the _& * value on the axis and the b * value on the y axis, and a hexagonal figure can be obtained by connecting adjacent points. This is called the color reproduction range (also called the color gamut or color rendering range). In this case, whether the color gamut is large or small can be seen on the figure, but cannot be expressed numerically. In the present invention, the sum of the densities of Y, M, C, and Bk (black) is simply used as a numerical value representing the color reproduction range.

Example

Hereinafter, the present invention will be described with reference to Examples, but is not of course limited thereto. First, a specific example of an ink jet recording medium in which an ink absorbing layer is provided on only one surface of a support will be described.

Examples 1 to 8 and Comparative Examples 1 to 10

The coating composition of the ink absorbing layer is composed of amorphous fine particles (Mizukasil P78A: oil absorption 245 m1 Z100 g, average secondary particle diameter 3.5 μm: manufactured by Mizusawa Chemical Co., Ltd.) 10 0 parts, Polyvier alcohol (PVA 117: Kurarene earth) 25 parts, Cationic dye fixing agent (Sumirezuzu resin 101: Sumitomo Chemical Co., Ltd.) 20 parts, mixed, ink absorption layer coating liquid A

The coating composition of the ink absorbing layer was composed of amorphous silica fine particles (fine seal X-60: oil absorption 24 Oml / 100 g, average secondary particle diameter 6.2 μχα: manufactured by Tokuyama Corporation) 100 parts, Silanol-modified polyvinyl alcohol (Rl 130: made of Kuraray clay) 20 parts, 20 parts of a cationic dye fixing agent (Violet Resin 1001: manufactured by Sumitomo Chemical Co., Ltd.) were mixed to prepare an ink absorbing layer coating solution B.

The coating composition of the ink absorbing layer was composed of amorphous silica fine particles (Mizukasil P 78 F: oil absorption 22 Oml / 100 g, average secondary particle diameter 12.0 μια: manufactured by Mizusawa Chemical Co., Ltd.) 100 parts, Polyvinyl alcohol (PVA 117: Kuraray Co., Ltd.) 15 parts, Silanol-modified Polyvinyl alcohol (Rl 130: Kurarene earth) 15 parts, Cationic dye fixing agent (Violet Resin 1001: Sumitomo Chemical Co., Ltd.) 20 parts were mixed to prepare the ink absorbing layer coating solution C.

Coating solution for ink absorbing layer D>

The coating composition of the ink absorbing layer was composed of 100 parts of amorphous silica fine particles (Mizukasil 5—50: oil absorption amount: 17 Oml / 100 g, average secondary particle size: 9.5: manufactured by Mizusawa Chemical Co., Ltd.) Livinyl alcohol (PVA117: Kuraray clay) 15 parts, Silanol-modified polybutyl alcohol (R110: Kuraray) 15 parts, cationic dye fixing agent (Violets resin 1001: Sumitomo Chemical) Co., Ltd.) (20 parts) was mixed to prepare an ink absorbing layer coating solution D.

The coating composition of the ink absorption layer was composed of 100 parts amorphous fine particles (Fine Seal X-37: oil absorption: 275 ml / 100 g, average secondary particle diameter: 2.7 μm: manufactured by Tokuyama Corporation), 25 parts of polyvinyl alcohol (PVA117: manufactured by Kuraray Co., Ltd.) and 20 parts of a cationic dye fixing agent (Sumitetsu Resin 1001: manufactured by Sumitomo Chemical Co., Ltd.) were mixed to prepare a coating solution E for an ink absorbing layer.

The coating and composition of the ink absorbing layer are made of amorphous silica fine particles (Nipseal VN3: oil absorption: 180-200 ml / 100g, average secondary particle diameter: 18. 8.μπι: manufactured by Nippon Siri Riki Co., Ltd.) 100 parts, Polyvinyl alcohol (PVA 117: manufactured by Kuraray Co., Ltd.) 25 parts, Cationic dye fixing agent (Sumiretzu Resin 1001: manufactured by Sumitomo Chemical Co., Ltd.) 20 parts were mixed, and the ink absorbing layer coating solution was mixed. F.

<Ink absorbing layer coating liquid G> 100 parts of amorphous silica fine particles (Mizukasil P832: oil absorption 145 ml / 100 g, average secondary particle diameter 2.5: manufactured by Mizusawa Chemical Co., Ltd.) 25 parts of PVA117: made of Kurarene earth) and 20 parts of a cationic dye fixing agent (Violets resin 1001: manufactured by Sumitomo Chemical Co., Ltd.) were mixed to prepare a coating solution G for the ink absorbing layer.

Production of jet recording medium>

Coating is performed using coated base paper (basis weight 1 57

The above coating liquids A to E were applied to a talc filler content of 6%, a cop size of 9 g / m ² , and acidic paper) using a wire bar so as to have a dry coating amount of 10 g / m ² . After the application, the ink jet recording medium was left standing at 90 ° C. for 10 minutes and dried to prepare an ink jet recording medium for the examples and comparative examples shown in Table 1.

The following pigments were respectively dispersed in the following liquid media to obtain an ink set composed of four color ink compositions.

《Pigment》

Yellow ink: C.I. Pigment Yellow 128

Magenta Inc .: C.I. Pigment Red 1 22

Cyan ink: C.I.

Black ink: Carbon black 4.5% by weight << Liquid medium >>

Styrene-methacrylic acid copolymer (dispersant) 1.5% by weight Grandul PP-1000

(Dainippon Ink, Styrene acrylic emulsion resin)

Manoleose

Glycerin 10% by weight Triethylene glycol monobutylinoleate

Acetylene glycol compound (Surfinol 465: penetrant)

1.5% by weight of ion exchange water The physical properties of the above-mentioned Ink Set 1 are

Viscosity: 3.0 to 3.8 mPa's, Surface tension: 3 ° to 40 NZm, H: 8.0 to 8.8.

Ink set 2>

Ink set 2 was obtained in the same manner as in ink set 1, except that the styrene-methacrylic acid copolymer as a dispersant was replaced with sodium polyacrylate.

Ink set 3 was obtained in the same manner as in ink set 1 except that the penetrant (Surfinol 465) was omitted.

These were refilled into EM900C (Seiko Epson: Inkjet Printer) cartridges, output using ink as shown in Table 1, evaluated, and the results are shown in Table 1.

Ku ink absorption evaluation>

The ink absorbability was evaluated by using these ink sets, printing a heavy-color rectangular pattern with cyan ink and magenta ink, and visually evaluating the boundary between this print pattern and the unprinted area according to the following criteria. .

◎: No bleeding was observed at the boundary

〇: Bleeding is hardly recognized at the boundary

Δ: Bleeding is observed at the boundary

X: noticeable bleeding at the boundary

Evaluations of ◎ to 〇 show good ink absorption “life”.

Evaluation of friction resistance>

The friction resistance was evaluated by using a black ink of these ink sets, printing a solid rectangular pattern, and rubbing with a nail or finger to evaluate the ink peeling.

〇: No problem

△: practical limit

X: Not allowed

Similarly, print solid yellow, magenta, cyan, and black, and record Was measured using a Macbeth densitometer (Mcbeth RD919, manufactured by Kollorgen Corporation). The higher the color density, the better. The sum of the densities of these four colors is referred to as the color reproduction range. In this case, the color reproduction range value is preferably 5.3 or more.

table 1

Coating liquid Ink ink Abrasion resistance Color density Color reproduction range Type Type Absorbability Friction Y M C B k

Example 1 A 1 ◎ 〇 1.37 1.28 1.36 1.56 5.57 Example 2 B 1 ◎ 〇 1.40 1.32 1.40 1.60 5.72 Example 3 C 1 ◎ 〇 1.36 1.27 1.34 1.52 5.49 Example 4 D 1 〇 2 1.32 1.25 1.32 1.48 5.37 Example 5 A 2 ◎ Δ 1.35 1.27 1.34 1.55 5.51 Example 6 B 2 ◎ Δ 1.37 1.30 1.38 1.56 5.61 Example 7 C 2 ◎ Δ 1.33 1.27 1.33 1.50 5.43 Example 8 D 2 〇 Δ 1.31 1.26 1.30 1.47 5.34 Comparative example 1 A 3 o X 1.25 1.18 1.28 1.37 5.08 Comparative Example 2 B 3 〇 X 1.23 1.20 1.27 1.39 5.09 Comparative Example 3 C 3 〇 X 1.27 1.20 1.31 1.40 5.18 Comparative Example 4 D 3 ΔX 1.25 1.19 1.28 1.36 5.08 Comparative Example 5 E 1 ◎ Δ 1.26 1.21 1.27 1.36 5.10 Comparative Example 6 F 1 ◎ △ 1.28 1.22 1.29 1.42 5.21 Comparative Example 7 G 1 △ △ 1.25 1.21 1.25 1.34 5.05 Comparative Example 8 E 3 〇 X 1.24 1.18 1.27 1.35 5.04 Comparative Example 9 F 3 OX 1.22 1.19 1.25 1.39 5.05 Comparative example 1 0 G. 3 Δ X 1.23 1.20 1.25 1.34 5.02 table 1, oil absorption of 1 50 m ^2/100 g or more, an average secondary particle size of 3. 0 mu m or more in 15 mu m or less preferred Examples 1, 2, 3, and 4 Compared with Comparative Examples 5, 6, and 7, it can be seen that the color reproduction range is wider when compared with the same ink (ink set 1). Examples 5, 6, 7, and 8 in which the polymer dispersant of the ink was sodium polyacrylate were more resistant than Examples 1, 2, 3, and 4 in which a styrene- (meth) acrylic acid-based dispersant was used. Although the friction decreased slightly, it was at the practical limit. Comparative Examples 1, 2, 3, and 4 using ink set 3 containing no penetrant had a narrower color reproduction range and abrasion resistance even with the same recording medium than Examples 1, 2, 3, and 4. Was not possible. Examples 1, 2, and 3 having an oil absorption of 20 Om 1/100 g or more were slightly superior in the color reproduction range as compared with Example 4 having an oil absorption of 170 ml / 100 g. The same can be said between Examples 5, 6, 7 and 8.

Next, a specific example of an ink jet recording medium in which an ink absorbing layer is provided on both surfaces of a support will be described. Examples 9 to 20 and Comparative Example 1:! ~ twenty four

Coating solution for ink absorbing layer A to G>

It was prepared in the same manner as the ink absorbing layer coating liquids A AG used in Examples 1 to 8 and Comparative Examples 1 to 10.

Production of jet recording medium>

The coating was performed by coating the above coating liquids A to E on a coated base paper (basic weight: 157 g Zm ² , talc filler content: 6%, cob size: 9 g Zm acidic paper) using a wire par as a support. Apply to the indicated surface dry coating amount, leave it at 90 ° C for 10 minutes, dry, and apply to the opposite surface also the back surface dry coating amount shown in Table 2. After drying in the same manner, ink jet recording media for Examples and Comparative Examples shown in Table 2 were produced.

Example;! To 8 and Comparative Examples 1 to 10: Prepared in the same manner as

These were refilled into EM900C (Seiko Epson: Inkjet Printer) power cartridges, output to both sides using ink as shown in Table 2, evaluated, and the results are shown in Table 2.

Ku ink absorption evaluation>

Evaluation was performed in the same manner as in Examples 1 to 8 and Comparative Examples 1 to 10.

Evaluation of friction resistance>

Similarly, solid printing of yellow, magenta, cyan, and black was performed, and the image density of the recorded portion was measured with a Macbeth densitometer (Mcbeth RD919, manufactured by Kollorgen Corporation). The higher the color density, the better. The sum of the densities of these four colors is referred to as the color reproduction range. In this case, the color reproduction range value is preferably 5.3 or more.

The strike-through was evaluated by visually observing the extent to which the image printed on both sides was seen through the back. ◎ No strikethrough is observed

殆ど Almost no strikethrough, no practical problem

Δ strikethrough is observed

x The strikethrough is so bad that it is not practical.

Good strike-through properties are evaluated from ◎ to △ _t

Table 2

From Table 2, oil absorption of 1 50m ² / l 00 g or more, an average secondary particle size of 3. 0 mu m or less than the 15 Myupaiiota, and coating weight of 7 g / m ² or more in Example 9, 10, 11, 12, 13 and 14 have a wider color reproduction range and better abrasion resistance when compared with the same ink (ink set 1) as compared to Comparative Examples 19, 20, and 21. You can see that. In Comparative Examples 11, 12, 13, and 14 with a coating amount of less than 7 g / m ² , when printed with the same ink (ink set 1), strikethrough is severe and not practical. Examples 15, 16, 16, 17, 18, 19, and 20 in which the polymer dispersant in the ink was sodium polyacrylate Examples 9 and 10 in which a styrene- (meth) acrylic acid-based dispersant was used. The abrasion resistance and the color reproduction range were slightly lower than those of, 11, 12, 13 and 14. In Comparative Examples 15, 16, 17, and 18 using the ink set 3 containing no penetrant, the color reproduction range was narrower than that of Examples 9, 11, 13, and 14, even with the same recording medium.

Industrial applicability ''

As described above, according to the present invention, it is possible to supply an ink jet recording medium having good absorbability, excellent ink pigment fixing property (abrasion resistance), and a wide color reproduction range. In particular, an ink jet recording medium useful as a recording medium when a pigment ink containing a styrene- (meth) atalylic acid-based water-soluble resin dispersant and an acetylene glycol compound penetrant is used can be supplied. In particular, in Examples 9 to 20, a double-sided ink jet recording medium excellent in these various properties can be supplied. In particular, even when printing is performed on both sides, a double-sided ink jet recording medium capable of obtaining good printed matter without strikethrough can be supplied.

Claims

Range of request

1. An ink jet recording medium for a pigment ink, comprising: a support; and an ink absorbing layer provided on one surface of the support, wherein a colorant pigment, a high-boiling organic solvent, In a recording medium for performing recording by discharging droplets of a pigment ink containing a dispersant, a penetrant and water, the ink absorption layer contains an inorganic pigment and a polymer adhesive, and the inorganic pigment is 1 A recording medium having an oil absorption specified in JIS K 5101 of not less than 50 mlZl 100 g and an average secondary particle diameter of not less than 3.0 βm and not more than 15 μm.

2. The recording medium according to claim 1, wherein the ink absorbing layer defined in claim 1 is further provided on another surface of the support.

3. The recording medium according to claim 2, wherein the ink absorbing layer is provided in an amount of 7 gZm ² or more and 20 gZn ^ or less.

4. The recording medium according to claim 1, wherein the ink absorbing layer further contains a cationic water-soluble resin.

5. The recording medium according to claim 2, wherein the ink absorbing layer further contains a cationic water-soluble resin.

6. The recording medium according to claim 1, wherein the dispersant for the pigment ink is a water-soluble styrene-mono (meth) atalilic acid resin, and the penetrant is an acetylenic alcohol compound.

7. The recording medium according to claim 2, wherein the dispersing agent for the pigment ink is a styrene-mono (meth) atalylic acid-based water-soluble resin, and the penetrating agent is an acetylene glycol compound.

8. An ink jet recording medium for pigment ink comprising a support and an ink absorbing layer, wherein the ink absorbing layer contains an inorganic pigment and a polymer adhesive, and the inorganic pigment is 15 Oml / Oil absorption of 100 g or more specified in JISK 5101,

3. A recording medium having an average secondary particle diameter of not less than 以上 μm and not more than 15 μm, comprising a coloring material pigment, a high boiling point organic solvent, a dispersant, a penetrant and water on the ink absorption layer. Use for recording by ejecting droplets of paint.