JP2002362015A - INK JET RECORDING MEDIUM AND ITS MANUFACTURING METHOD - Google Patents

Abstract

(57) [Summary] Visually, a recording medium itself resembles printing paper of offset or gravure printing, and its image resembles the printed matter of the printing, and can cope with higher image quality and higher speed. Provided are an ink jet recording medium having ink absorption performance and a method for manufacturing the same. A porous intermediate layer mainly composed of inorganic fine particles and an ink receiving layer coated with a dispersion of thermoplastic organic fine particles are provided on a support, and an average particle of the thermoplastic organic fine particles of the ink receiving layer is provided. The particle size of the thermoplastic organic fine particles is 30 to 150 nm, and the Tg of the surface of the thermoplastic organic fine particles is 50 to 100 ° C. It is characterized in that a dispersion liquid of fine particles is applied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an ink jet recording medium suitably used for printing using an ink jet technique and a method of manufacturing the same. In particular, the present invention relates to an ink jet recording medium that has good ink receptivity, has an appropriate glossiness, and provides high-quality images with good color development when high-quality images and characters are printed at high speed.

[0002]

2. Description of the Related Art In recent years, various types of printers for computer output have become widespread. Above all, an ink jet printer is excellent in quietness, cost, and image quality, can reproduce a full-color image with high quality, has excellent performance not found in other systems, and can be expected to spread further. Especially in recent years,
With the control of ink droplets, the development of light and dark inks, and the improvement of the performance of the ink receiving layer, the technology has been advanced until images equivalent to silver halide photographs can be obtained. In the above-mentioned ink jet recording system, it is common to use an aqueous ink as the ink and use a recording paper having an ink receiving layer formed on a support as a recording paper.

[0003] Here, a general technical example of a recording medium is as follows. By providing a receiving layer in which porous silica is dispersed in polyvinyl alcohol and adding a cation component as a recording medium, a physical effect is obtained. A method of chemically fixing a dye by absorbing ink into silica pores and adding a cationic component, or a method of chemically fixing a dye with alumina while physically absorbing the ink using an alumina sol. Or a method of using a cationic resin to chemically fix a dye by a cation portion while physically absorbing the ink by swelling.

[0004] However, in the method of absorbing ink by swelling of the cationic resin, a good image cannot be obtained in high-speed printing or printing with a large amount of ink because the receiving portion has high gloss but the ink absorption speed is low. In the method using silica or alumina, the printability of the ink-jet ink is good, but the gloss of the receiving portion is low and the gloss of the print portion tends to be low due to the large mixing ratio of the filler.

Therefore, in Japanese Patent Application Laid-Open No. 9-156210, 40% or more of the filler (pigment) to be blended is BET from the viewpoint that the swollen resin lowers the gloss of the printed portion.
By using porous silica having a surface area of 200 to 600 m ² / g, further defining the compounding ratio of casein and urethane resin, and applying and drying this material by cast coating, the gloss of the printed portion does not decrease. An ink jet recording medium is shown. Further, JP-A-11-288
No. 405, the outermost layer of the coating layer has an average primary particle size of 3 to 40 nm and an average secondary particle size of 10 to 40 nm.
There is a description of an ink jet recording medium containing silica fine particles having a thickness of 300 nm, forming an outermost layer, and then applying heat and pressure by a heat calender having a mirror-finished roll. However, in such a recording medium,
Many of them have been developed for silver halide photography, particularly for the purpose of improving image quality and glossiness. Therefore, not only the printed matter but also the recording medium itself has a texture similar to that of silver halide photographic printing paper, and has a different texture from printing paper used for offset printing or gravure printing. Furthermore, with regard to prints, although high glossiness like a photograph can be obtained,
This is different from a texture like a normal offset printed matter or a gravure printed matter. Many of these silver halide photographs have been developed specifically for the purpose of improving image quality and glossiness in recent years.
In a high-quality printer using inks of light cyan, light magenta, and the like in addition to yellow and black, the amount of ink printed per unit area increases. Due to the increase, the ink absorption speed and the absorption capacity of the ink in the receiving layer cannot be sufficiently coped with, and many images can be printed with good image quality.

[0006]

That is, in the prior art, although it is suitable for obtaining the texture and printed matter of a recording medium similar to a silver halide photograph, it is not suitable for expressing printed matter of offset printing or gravure printing. However, unlike the printing paper, the texture and gloss of the recording medium itself were not satisfactory.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and the ink jet recording medium itself has a texture similar to offset printing or gravure printing paper. In addition, the obtained image is an ink jet recording medium having a texture similar to that of a printed matter by offset printing or gravure printing, and ink jet recording having ink absorption performance capable of responding to high image quality and high speed of recent ink jet printers. A medium and a method for manufacturing the medium are provided.

[0008]

Means for Solving the Problems The present invention has been made to achieve the above object, and has a porous intermediate layer mainly composed of at least inorganic fine particles on a support; Is an ink jet recording medium provided with an ink receiving layer by applying a dispersion of thermoplastic organic fine particles, wherein the average particle diameter of the thermoplastic organic fine particles forming the ink receiving layer is in the range of 30 to 150 nm. Yes,
In addition, the present invention provides an inkjet recording medium characterized in that at least the glass transition point of the surface of the thermoplastic organic fine particles is 50100 ° C (claim 1).

On a support, a porous intermediate layer containing at least inorganic fine particles as a main component has a good ink absorbability and good printability as in a conventional general ink jet recording medium, but has a good filler property. Due to the large mixing ratio, the gloss of the receiving portion is low, and the gloss of the printing portion is also likely to be low. The intermediate layer is coated with a dispersion of thermoplastic organic fine particles having an average particle diameter in the range of 30 to 150 nm and at least a Tg of the particle surface of 50 to 100 ° C., thereby providing an ink receiving layer to provide a smooth surface. It is possible to form a film having a high property and having a void for quickly absorbing the ink and penetrating into the lower layer. This is a particle in which the thermoplastic organic fine particles are generally spherical and have a uniform particle diameter as compared with the inorganic fine particles in the intermediate layer, and the particles are closest packed to form a film while having voids. As a result, it is possible to obtain an ink receiving layer having a moderate gloss close to that of a printing paper, instead of a high gloss like a silver halide photograph. In addition, the thermoplastic organic fine particles are not provided as a single layer on the support, but are provided on a porous intermediate layer mainly composed of inorganic fine particles so that more ink can be absorbed. As a result, it is possible to obtain an ink-jet recording medium having an ink absorbing property corresponding to a high-quality, high-speed ink-jet printer. A porous intermediate layer mainly composed of inorganic fine particles was coated with a dispersion of thermoplastic organic fine particles to form a dispersion layer of thermoplastic organic fine particles thereon to form a receiving layer composed of thermoplastic organic fine particles thereon. Sometimes it is necessary to absorb the thermoplastic organic fine particles and maintain the porosity without filling the pores inside the intermediate layer.

In the present invention, the intermediate layer preferably comprises at least inorganic fine particles and a resin, the inorganic fine particles have an average particle diameter of 1 μm to 10 μm, and the weight ratio of the inorganic fine particles to the resin is 10: 1. 2. An ink jet recording medium according to claim 1, wherein the ratio is in the range of 10 to 5 (claim 2). At the time of printing by ink jet, the solvent of the ink for ink jet absorbed in the receiving layer composed of the thermoplastic organic fine particles must be further absorbed into the intermediate layer. Therefore, the average particle diameter of the inorganic fine particles is 1
-10 μm, and the weight ratio of the inorganic fine particles to the resin is 1
By using an intermediate layer in the range of 0: 1 to 10: 5,
A porous intermediate layer is obtained which does not absorb the thermoplastic organic fine particles into the interior and can sufficiently absorb the solvent of the inkjet ink.

Further, the present invention provides a method for disposing a dispersion of the thermoplastic organic fine particles of the receptor layer on an intermediate layer by coating.
3. The method according to claim 1, wherein the drying temperature is set to a temperature equal to or higher than the glass transition point of the thermoplastic organic fine particles and lower than the softening point. (Claim 3). When applying a dispersion of thermoplastic organic fine particles on the intermediate layer, since it is necessary to fuse the thermoplastic organic fine particles to form a film, it is necessary to set the drying temperature to Tg or more of the thermoplastic organic fine particles, In addition, if the drying temperature is too high, the thermoplastic organic fine particles are softened, the shape of the particles is broken, and the pores between the particles are not filled, so that the drying temperature must be lower than the softening point of the thermoplastic organic fine particles.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The ink jet recording medium of the present invention will be described below in detail. The ink jet recording medium according to the present invention is an ink jet recording medium in which an ink receiving layer is provided by coating a dispersion of thermoplastic organic fine particles on a support, on which a porous intermediate layer mainly composed of inorganic fine particles is formed. Recording medium, wherein the average particle diameter of the thermoplastic organic fine particles forming the ink receiving layer is 3
An inkjet recording medium having a range of 0 to 150 nm and a Tg of at least the surface of the thermoplastic organic fine particles of 50 to 100 ° C.

If the thermoplastic organic fine particles are large, not only the receiving layer will not be smooth and lose gloss but also the receiving layer will become cloudy and not transparent, and a sufficient color density will not be obtained when ink-jet ink is absorbed. . Therefore, the average particle diameter is preferably 30 to 150 nm. Although the thermoplastic organic fine particles smaller than 30 nm tend to have high gloss and transparency, the dispersion in the dispersion liquid becomes unstable, so that not only an aggregate is easily formed, but also it is easily absorbed into the pores of the intermediate layer. Even when a layer is formed, the pores formed between the thermoplastic organic fine particles become small, and the speed of absorbing ink jet ink becomes slow.

Further, the thermoplastic organic fine particles need to be fused by heating by drying at the time of forming the receptor layer while maintaining the gap between the thermoplastic organic fine particles to form a film. The temperature at which the dispersion of the thermoplastic organic fine particles is applied and dried depends on the solvent of the dispersion and the type of the support, but is usually around 100 ° C. If the thermoplastic organic fine particles having an excessively low Tg are used, the voids will be closed at the time of drying, and the absorptivity of the inkjet ink will be lost, and even if the voids remain, blocking or the like during the production or storage of the inkjet recording medium is likely to occur. . On the other hand, if the Tg is too high, no fusion occurs between the thermoplastic organic fine particles and a film is not formed, so that the receiving layer is brittle and falls off, so that a layer cannot be formed. Considering the above, the thermoplastic organic fine particles are fused by heating by drying during the formation of the receiving layer while maintaining the voids between the thermoplastic organic fine particles to form a film. Organic fine particles having a Tg of 50 to 100 ° C. are preferably used.

The porous intermediate layer mainly composed of inorganic fine particles must further absorb the solvent of the inkjet ink absorbed by the receiving layer composed of the thermoplastic organic fine particles into the intermediate layer during printing of the inkjet ink. Therefore, a sufficient porous structure must be formed. This is to apply a dispersion of thermoplastic organic fine particles to form a receiving layer composed of thermoplastic organic fine particles on top,
This means that when the dispersion of the thermoplastic organic fine particles is applied, the thermoplastic organic fine particles must be absorbed and the pores inside the intermediate layer must not be filled to maintain the porosity. Therefore, the use of an intermediate layer in which the average particle diameter of the inorganic fine particles is 1 to 10 μm and the weight ratio of the inorganic fine particles to the resin is in the range of 10: 1 to 10: 5 allows absorption into the inside of the thermoplastic organic fine particles. Thus, an intermediate layer having a porosity which can sufficiently absorb the solvent of the ink jet ink can be obtained. 1 inorganic fine particles
When the average particle diameter is larger than 0 μm, the pores of the intermediate layer become large and the smoothness of the intermediate layer is deteriorated, and even when a dispersion of the thermoplastic organic fine particles is applied, the thermoplastic organic fine particles enter the pores of the intermediate layer. Absorbed ink does not have a luster or cannot absorb the solvent of the inkjet ink sufficiently to close the holes in the intermediate layer. On the other hand, if the average particle diameter is smaller than 1 μm, the pores of the intermediate layer itself become small, and it becomes impossible to sufficiently absorb the solvent of the inkjet ink. When the weight ratio of the inorganic fine particles to the resin is larger than 10: 5, the intermediate layer does not have enough holes to absorb the solvent of the inkjet ink, and when the resin ratio is smaller than 10: 1, the intermediate layer becomes brittle. Not only does the ink jet recording medium lose its resistance, but also when the dispersion of thermoplastic organic fine particles is applied, problems such as the intermediate layer being scraped off or falling off occur.

The drying temperature when the dispersion liquid of the thermoplastic organic fine particles is provided on the intermediate layer by coating is set to a temperature equal to or higher than the Tg of the thermoplastic organic fine particles in order to fuse the thermoplastic organic fine particles to form a film. When dried at a temperature lower than Tg, the film is not formed because the thermoplastic organic fine particles do not fuse with each other. However, if the temperature is too high, the thermoplastic organic fine particles are softened, melted and deformed to close the pores between the thermoplastic organic fine particles, so that the temperature is lower than the softening point.

As the support used in the present invention, a support made of any available material can be used. Examples include various papers such as synthetic paper, high-quality paper, art paper, coated paper, cast-coated paper, and paperboard, and polyethylene terephthalate, polyethylene naphthalate, polyvinyl chloride, polycarbonate, cellophane, and polyethylene. Resins using the above-mentioned resins, those obtained by combining the above-mentioned papers and films by lamination or the like, and other suitable materials such as glass and wood. In particular, the use of printing paper such as coated paper is preferable because the texture of the recording medium is more similar to the texture of the printing paper. The surface of the support may be subjected to a corona discharge treatment or a known easy adhesion treatment such as an anchor layer made of a polyurethane resin or the like for the purpose of improving the adhesion of the ink image receiving layer.

The intermediate layer used in the present invention is a porous intermediate layer mainly composed of inorganic fine particles and using a resin as a binder, and is an inorganic fine particle generally used as inorganic fine particles.
In particular, those having an average particle diameter of 1 to 10 μm can be used. Although the type is not particularly limited, for example, porous silica prepared by a gel method or a precipitation method, fumed silica prepared by a dry method, kaolin, clay, calcium carbonate, titanium oxide, zinc oxide, magnesium oxide, oxide Examples include aluminum, magnesium hydroxide, aluminum hydroxide, hydrotalcite, and the like. Above all, the average particle system is 1
Use of porous silica of 10 to 10 μm is very preferable because physical absorption is obtained and drying property is improved.
Since these porous silicas are inexpensive, they are very desirable in terms of production cost.

The resin used in the intermediate layer is for binding and holding inorganic fine particles to form a porous film. Examples of the resin include polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene oxide, polyethylene glycol, polyethylene imine, polypropylene oxide, and the like.
Sulfonated polyethylene, polyvinyl pyridine, polyacrylate, polyacrylamide, polymethacrylate, polymethacrylamide, polyurethane, poly N-
Solvent-philic, such as vinylacetamide, preferably hydrophilic polymers and derivatives or cross-linked polymers thereof, starch, gelatin, polymerizable monomers that become water-soluble by hydrolysis or polysaccharides such as cellulose, such as acrylic acid, Acrylate, acrylate, acrylamide, methacrylic acid, methacrylate, methacrylamide, acrylonitrile, methacrylonitrile,
An oligomer such as maleic acid, sulfonated styrene, or polyvinylpyridine is graft-polymerized and, if necessary, hydrolyzed to obtain a hydrophilic polymer and a derivative or cross-linked polymer thereof.

In the present invention, a dye fixing agent, a fluorescent whitening agent, a surfactant, an antifoaming agent,
Additives such as a regulator, a fungicide, an ultraviolet absorber, an antioxidant, and a dispersant may be contained. These additives may be arbitrarily selected from conventionally known compounds according to the purpose.

In forming the intermediate layer of the present invention on a support, inorganic fine particles and a resin are blended in a range of 10: 1 to 10: 5 by using a conventionally known coating liquid preparation method. Add an additive as necessary and use a disperser or the like to dissolve or disperse and mix to prepare a coating liquid, and also apply a conventionally known method such as a roll coater method or a blade coater method. It is applied to the substrate surface by an air knife coater method, a gate roll coater method, a size press coater method or the like. Thereafter, for example, drying is performed using a hot-air drying furnace, a hot drum, or the like, and an intermediate layer can be provided on the support.

The coating thickness of the intermediate layer in the present invention needs to be thick enough to have a space enough to absorb the solvent of the ink jet ink at the time of printing. If the coating thickness is too small, the solvent of the printed ink-jet ink cannot be completely absorbed, causing bleeding or unevenness of the image, or insufficient drying of the surface of the receiving layer, causing image flow or sticking. On the other hand, if the thickness is too large, cracks and falling off of the intermediate layer may occur, and problems such as coating, drying property and cost in production may occur. For this reason, the thickness of the intermediate layer is preferably set as appropriate according to the composition of the inorganic fine particles and the resin of the intermediate layer and the amount of ink jet ink to be printed, but is generally preferably 5 to 30 g / m ² in terms of dry weight.

As the thermoplastic organic fine particles used in the receptor layer of the present invention, conventionally known thermoplastic organic fine particles having an average particle diameter in the range of 30 to 150 nm and at least a Tg of the particle surface of 50 to 100 ° C. are used. . In particular, known synthetic resin emulsions can be used, for example, acrylic, acryl-styrene, styrene butadiene, vinyl acetate, ethylene-vinyl acetate, polyester, urethane, epoxy-based resin emulsions and modified resins and synthetic resins thereof. Emulsions or mixtures of resins are used. These thermoplastic organic fine particles are not uniform particles, but may be hollow or multilayered thermoplastic organic fine particles.

The receptor layer of the present invention may contain a dye fixing agent, a fluorescent whitening agent, a surfactant, an antifoaming agent, if necessary, similarly to the intermediate layer.
Additives such as a pH adjuster, a fungicide, an ultraviolet absorber, an antioxidant, and a dispersant may be contained. These additives may be arbitrarily selected from conventionally known compounds according to the purpose.

In forming the receptor layer of the present invention on the intermediate layer, a known coating method such as a roll coater method or a blade coater method may be used in the same manner as in forming the intermediate layer on the support. The surface of the intermediate layer is coated by an air knife coater method, a gate roll coater method, a size press coater method, or the like. Thereafter, for example, drying is performed using a hot-air drying furnace, a hot drum, or the like, and an intermediate layer can be provided on the support.

In the present invention, if the coating thickness of the receptor layer is too small, the unevenness of the intermediate layer cannot be covered and a smooth layer cannot be formed, resulting in low gloss. Problems, such as coating and drying properties during production and costs. Therefore, the dry weight is preferably 1 to 10 g / m ² .

[0027]

Examples of the present invention will be described below. -Support: printing paper OK Topcoat V (manufactured by Oji Paper)-Intermediate layer silica: X-37B (manufactured by Tokuyama), average particle diameter 3.7 μm, 10 parts by weight polyvinyl alcohol: PVA-117 (manufactured by Kuraray Co., Ltd.) 4 parts by weight Water 86 parts by weight The composition of the above-mentioned intermediate layer, which was dissolved and dispersed by a ball mill, was applied to a support with a wire bar, and 100 ° C.
For 5 minutes to form an intermediate layer having a dry weight of 20 g / m ² . -Receiving layer Acrylic emulsion A, average particle diameter 80 nm, Tg6
0 ° C., softening point 120 ° C. dispersion medium water, solid content 35% A receiving layer having a solid content of 35% or more is applied on the intermediate layer by a wire bar and dried at 100 ° C. for 5 minutes to form a receiving layer having a dry weight of 5 g / m ^2. Then, a recording medium for inkjet was prepared. The surface glossiness (60 °) of the ink jet recording medium thus obtained was measured, and the film strength of the receiving layer was confirmed by a cellophane tape peeling test. In addition, a Canon inkjet printer (product name; BJF850)
Was used to form an evaluation image, and the image was evaluated. The print density was measured by measuring the optical reflection density of a solid black print portion using Macbeth RD918. Hereinafter, Table 1 shows a list of Examples and Comparative Examples, surface glossiness, and printing results of ink jet recording media similarly produced by changing the composition and the structure.

[0028]

[Table 1]

As is evident from Table 1, the ink jet recording medium of the present invention has the same glossiness as printing paper, has the texture as if it were printed by offset printing or the like, and has high speed and high image quality. High-quality printing without blurring of images has become possible even with an inkjet printer.

[0030]

According to the present invention, a high-quality image without blurring can be obtained even in a high-speed and high-quality ink jet printer. Further, the image can be obtained as if by a so-called offset printing or gravure printing. An ink jet recording medium exhibiting excellent gloss and texture and a method for manufacturing the same can be provided.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram schematically showing an example of an inkjet recording medium of the present invention in a longitudinal sectional view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Ink-jet recording medium 2 ... Support body 3 ... Intermediate layer 4 ... Reception layer

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yasuo Sugishita 1-5-1, Taito, Taito-ku, Tokyo Toppan Printing Co., Ltd. (72) Inventor Satoshi Kazuya 1-1-1, Taito, Taito-ku, Tokyo Letterpress F-term (reference) in Printing Co., Ltd. 2C056 EA04 FC06 2H086 BA16 BA33 BA36 BA41 BA45

Claims (3)

[Claims] 1. An ink-jet method comprising: a porous intermediate layer mainly composed of at least inorganic fine particles on a support; and an ink receiving layer provided by applying a dispersion of thermoplastic organic fine particles on the intermediate layer. Wherein the average particle diameter of the thermoplastic organic fine particles forming the ink receiving layer is in the range of 30 to 150 nm, and the glass transition point of at least the particle surface of the thermoplastic organic fine particles is 5
A recording medium for inkjet recording, which is at 0 to 100 ° C. 2. The intermediate layer comprises at least inorganic fine particles and a resin, and the inorganic fine particles have an average particle diameter of 1 μm or less.
10 μm, and the weight ratio of the inorganic fine particles to the resin is 10:
2. The ink jet recording medium according to claim 1, wherein the ratio is in the range of 1 to 10: 5. 3. When the dispersion liquid of the thermoplastic organic fine particles of the receiving layer is provided on the intermediate layer by coating, the drying temperature is higher than the glass transition point of the thermoplastic organic fine particles and lower than the softening point. 3. The method according to claim 1, wherein the temperature is set to a temperature.