JP2003320746A - Inkjet recording body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the adhesion between an ink receiving layer and a support, eliminate coating defects of the ink receiving layer and further obtain a higher quality appearance and lustrous feeling. <P>SOLUTION: In an inkjet recording body having one or more ink receiving layers on a support, an undercoating layer including at least one kind selected from the group consisting of a polyolefin-based polymer, α-olefin-unsaturated carboxylic acid copolymer and a polyester-based copolymer on the support and, at the same time, an aqueous paint including an electron beam curing component forming a hydrogel through irradiation of an aqueous solution with the electron beam is applied to the ink receiving layer in contact with the undercoating layer and then the resultant applied layer is made to hydrogel through the irradiation with the electron beam and dried so as to finish the ink receiving layer. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet recording material which is excellent in visual appearance and glossiness and suitable for full-color photographic printing.

[0002]

2. Description of the Related Art Conventionally, various systems such as a wire dot recording system, a thermosensitive color recording system, a fusion thermal transfer recording system, a sublimation recording system, an electrophotographic system and an inkjet recording system have been developed for output of a computer or the like. .
Among them, the inkjet recording method, since it is possible to use plain paper as a recording sheet, the running cost is low, the hardware is compact and inexpensive,
It is recognized as a recording method suitable for personal use. Furthermore, in recent years, full-color and high-resolution have been dramatically advanced, and they are attracting attention as an easy output means for color images, and the number of printers sold is rapidly increasing.

The basic properties of an ink jet recording material used for output of an ink jet printer are that ink can be quickly absorbed to reproduce fine characters or images, that the color density of the image is high and that the color tone is not biased. is necessary. In addition, in recent years, when the performance of inkjet printers has rapidly advanced, the output applications are expanding from simple monochrome character output to digital image output that is a substitute for silver halide photography, so the inkjet recorder side also has user needs. In particular, for image output, there is a demand for visual quality that is close to that of a silver salt photograph (visual appearance, glossiness, etc.).

Previously polyvinyl alcohol on a support,
Many inkjet recording materials manufactured by coating an aqueous solution of a water-soluble resin such as polyvinylpyrrolidone, a water-soluble cellulose derivative and gelatin, and drying the product have been commercially available.
With these recording materials, a high-gloss inkjet recording material can be easily manufactured at low cost. However, a recording material having an ink-receiving layer containing a water-soluble resin as a main component on a support has a low ink drying speed, cannot support high-speed printers, and has poor water resistance. Inkjet recording materials having a porous ink-receiving layer obtained by solidifying a small amount of a binder resin have become mainstream.

The fine pigment-based ink receiving layer produced by solidifying fine pigments with a binder resin quickly absorbs ink by capillarity in the pores secured inside and outside of the pigment to form an image, and therefore, is dissolved or swelled. It is possible to obtain a higher level of image and ink drying property as compared with a resin-based receiving layer that absorbs ink. Further, the fine pigment-based receiving layer has an advantage that if the binder resin has water resistance, the water resistance of the receiving layer can be very high. However, on the other hand, in order to obtain a high-quality image in the fine pigment-based receiving layer, it is necessary to secure pores in the receiving layer that can absorb the ejected ink, and the amount of ejected ink is large. A high coating amount is required for the inkjet recording material for the inkjet printer for photo printing. In addition, the pigment used must have a large pore volume, and in order to obtain high gloss, it must be a uniform fine pigment having an average particle size smaller than the wavelength of light. When such a fine pigment is used, cracking of the receiving layer is likely to occur due to capillary force in the drying process after coating, and it is very difficult to obtain a coating amount sufficient for ink absorption by one coating. Therefore, usually, the required coating amount is secured by repeating low coating amount many times, but the production process becomes complicated and the yield decreases due to the large number of coatings. There was a problem that it deteriorated.

[0006]

In order to overcome such problems, the present inventors have conceived to utilize the crosslinking reaction of the resin by electron beam irradiation. In particular, paying attention to a water-soluble resin that forms a hydrogel by irradiating an aqueous solution with an electron beam, such as polyvinyl alcohol, an aqueous composition containing such a resin as a main component is applied to a support sheet, and then, We have found a method of forming an ink receiving layer by irradiating an electron beam to form a hydrogel and then drying it. It was found that the ink-receiving layer formed has dramatically improved performance of the receiving layer and has a simpler manufacturing process, as compared with the case where the electron beam is not irradiated or the dried coating film is irradiated with the electron beam. It was That is, by using this production method, even when using a fine pigment having a large pore volume that easily causes cracks, it is possible to form a good receiving layer without cracks and obtain a high-definition image. (Patent application 2
000-323429).

The inventors of the present invention further studied the method of hydrogelizing the coating layer by electron beam irradiation, and as a result, the texture (visual appearance) and glossiness were reduced depending on the support used. It was found that the quality as an inkjet recording material for photo printing cannot be obtained. As a result of a detailed study on the cause, the smoothness of the support,
The surface physical properties of the support such as wettability (contact angle) and size have a great influence on the ink receiving layer formed thereon,
In some cases, a coating defect is given to the surface of the ink receiving layer,
It was found that the texture and luster of appearance were reduced. For example, on a support with large surface irregularities and low smoothness, a plastic film with high hydrophobicity, a support laminated with a highly hydrophobic resin, or a support with low wettability such as sized paper When applying a water-based paint, even if it can be applied without repellency of the paint on the appearance,
The quality of the obtained ink jet recording material deteriorated. It is presumed that this phenomenon causes unevenness in thickness or defective wetting in the coating layer, which causes unevenness in coating film shrinkage during drying and defects in the coating layer, resulting in quality deterioration.

Further, the method of the present inventors, that is, the method of irradiating the coating layer in an aqueous solution state with an electron beam to form a hydrogel and then drying it to obtain an ink receiving layer is a conventional method without electron beam irradiation. It was found that the quality of the coating layer before drying was more likely to affect the quality of the coating layer after drying than by the method.
This is considered to be because the hydrogelized coating layer is in an immobilized state, and it is more difficult to relax the stress generated inside the coating layer due to drying shrinkage than in the case of a normal method. Therefore, there is a non-uniform surface in the ink receiving layer before drying,
If the adhesiveness between the support and the ink receiving layer is insufficient, it is considered that the strain is amplified by the drying shrinkage and the coating layer defects become obvious. Therefore, in the method of the present inventors, increasing the uniformity of the coating layer before drying and improving the adhesion between the ink receiving layer and the support can eliminate defects in the coating layer, and further improve It was concluded that it is important for obtaining a level visual appearance and glossiness, and is necessary for obtaining a high-performance inkjet recording material.

An object of the present invention is to provide an ink jet recording material which is improved in the drawbacks of the above-mentioned ink jet recording material using an electron beam and is excellent in visual appearance and glossiness and suitable for full color photographic printing.

[0010]

[Means for Solving the Problems] The present inventors diligently studied a method for obtaining an excellent visual appearance and glossiness. As described above, in the present invention, increasing the uniformity of the coating layer before drying is an important factor not only for eliminating defects in the coating layer, but also for obtaining a higher level of visual appearance and glossiness. . In order to increase the uniformity of the coating layer before drying, it is preferable to optimize the surface physical properties of the ink receiving layer coating surface,
Examples of commonly used methods include various treatments such as smoothing treatment with a metal roll, resin laminating treatment, corona discharge treatment, plasma discharge treatment, solvent treatment, and formation of an undercoat layer. Among these, the formation of the undercoat layer is effective, and it has been found that the undercoat layer made of a specific material is very effective, and the present invention has been completed.

The present invention includes the following aspects. [1] In an inkjet recording material having one or more ink receiving layers on a support, a polyolefin-based polymer, an α-olefin / unsaturated carboxylic acid copolymer, and a polyester-based copolymer are selected on the support. The ink-receiving layer having an undercoat layer containing at least one of the above-mentioned, and the ink receiving layer in contact with the undercoat layer forms a hydrogel by irradiating an aqueous solution with an electron beam. An inkjet recording material, which is an ink-receiving layer formed by irradiating an electron beam to hydrogel the coating layer and then drying.

[2] The ink jet recording material according to [1], wherein the undercoat layer contains colloidal silica.

[3] The ink jet recording material according to [1] or [2], wherein the coating amount of the solid content of the undercoat layer is 0.1 to 30 g / m ² .

[4] At least one ink-receiving layer formed by irradiating an electron beam to hydrogel the coating layer and then drying the coating layer contains fine pigments having an average particle diameter of 1 μm or less, and has a pore diameter of 1 μm or less. Total pore volume of 100 nm or less is 0.2 to
The inkjet recording material according to any one of [1] to [3], which has a porous ink receiving layer of 2.0 ml / g.

[5] An electron beam curable component that forms a hydrogel by irradiating an aqueous solution with an electron beam is polyvinyl alcohol, polyethylene oxide, polyalkylene oxide, polyvinylpyrrolidone, water-soluble polyvinyl acetal, poly-N-vinyl. At least one selected from the group consisting of acetamide, polyacrylamide, polyacryloylmorpholine, polyhydroxyalkyl acrylate, polyacrylic acid, hydroxyethyl cellulose, methyl cellulose, hydroxypropylmethyl cellulose, hydroxypropyl cellulose, gelatin, casein, and water-soluble derivatives thereof. The inkjet recording material according to any one of [1] to [4], which is a hydrophilic resin.

[6] The ink jet recording material according to any one of [4] and [5], wherein the fine pigment is at least one selected from the group consisting of silica, aluminum hydroxide, boehmite, pseudo-boehmite, and alumina.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. The undercoat layer of the present invention is a layer formed by coating and drying before coating the ink receiving layer, and a suitable ink receiving layer coating whose surface physical properties are always stable regardless of the type of support. A surface is added. Such an undercoat layer is preferably one which can maintain a uniform coating layer of the ink receiving layer before drying and has high adhesion to the ink receiving layer. As a result of intensive studies by the present inventors, as a resin that can be preferably used in the undercoat layer, a polyolefin-based polymer, α-
We have found olefin / unsaturated carboxylic acid copolymers and polyester copolymers. Particularly preferred are α-olefin / unsaturated carboxylic acid copolymers and polyester copolymers. By forming the ink receiving layer on the undercoating layer containing such a resin as a main component, it is possible to improve the adhesiveness and avoid unevenness and defects in the coating layer. Even when other resins are used as the undercoat layer, there are some in which defects and visual appearance of the coating layer are improved as compared with the case where there is no undercoat layer, but the undercoat layer of the present invention is particularly effective. Excel.

The polyolefin polymer used in the present invention comprises, for example, a homopolymer of an olefin monomer such as polyethylene, polypropylene, polybutene and polypentene, and two or more kinds of olefin such as an ethylene-propylene copolymer. Examples thereof include copolymers and mixtures thereof. The molecular weight of the polyolefin-based polymer is not particularly limited, but those having a molecular weight of 50,000 to 300,000 are generally commercially available and preferred. Examples of commercially available products of such a polyolefin-based polymer include Hitec E-800.
0, E-8045 (manufactured by Toho Chemical Industry Co., Ltd.) and the like.

As the α-olefin constituting the α-olefin / unsaturated carboxylic acid copolymer, ethylene, propylene, butylene and the like are preferable, and ethylene is particularly preferable. As the unsaturated carboxylic acid, acrylic acid, methacrylic acid, maleic acid, itaconic acid, fumaric acid and the like are preferable, and acrylic acid and methacrylic acid are particularly preferable. A copolymer of ethylene and acrylic acid or methacrylic acid (hereinafter both are abbreviated as (meth) acrylic acid), and a copolymer of propylene and a (meth) acrylic acid copolymer are commercially available. Can be used.
The weight average molecular weight of the α-olefin / unsaturated carboxylic acid copolymer is preferably 5,000 to 100,000, and particularly preferably 10,000 to 50,000. When the weight average molecular weight is less than 5,000, low molecular weight components are increased, which facilitates blocking (a phenomenon such as fusion or sticking that occurs due to heat, pressure, or aging), and the adhesion between the undercoat layer and the hydrogel. It may decrease. Further, if the average polymerized molecular weight exceeds 100,000, the production becomes difficult. Examples of commercially available products include Hitec S-312 as an emulsion type.
1, high-tech S-3123, high-tech S-3127
(All manufactured by Toho Chemical Industry Co., Ltd.), and examples of the alkali-soluble type include Zyksen-AC, Zyksen-N, and Zyksen-L (all manufactured by Sumitomo Seika). The effect as an undercoat layer does not change between the emulsion type and the alkali-soluble type.

The polyester copolymer is a resin produced by polycondensation of a polyhydric alcohol and a polybasic acid, and includes glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol and butylene glycol, and anhydrous phthalic acid. A polycondensation product of an acid, an aliphatic dibasic acid such as maleic anhydride, fumaric acid or adipic acid, or an aromatic dibasic acid such as terephthalic acid is generally used. As a commercial product, Bayronal MD-1
400, MD-1200 (all manufactured by Toyobo) and the like. The resin used for the undercoat layer is preferably a completely water-based resin from the viewpoint of manufacturing equipment and environmental consideration.

The above-mentioned undercoat layer is preferably formed on the support at a solid content of 0.1 to 30 g / m ² . It is more preferably 0.6 to 20 g / m ^2, further preferably 1 to 15 g / m ² , and most preferably 3 to 10 g.
g / m ² . When the solid content coating amount is small, the effect of improving the visual appearance is small, and when the solid content coating amount is large, it is not preferable in terms of cost.

It is preferable to add a pigment to the undercoat layer because the coating strength of the undercoat layer can be increased. Since the ink receiving layer coated on the undercoat layer has an extremely large shrinkage during drying, cracks may occur when the undercoat layer has low strength, but it can be improved by incorporating a pigment. As the pigment, a fine pigment having an average particle diameter of 1 μm or less is preferable because it does not reduce gloss. In particular, when colloidal silica is blended, a good visual appearance is obtained, and the adhesiveness to the ink receiving layer is good, which is particularly preferable. Several methods are known for producing colloidal silica. For example, in US Pat. No. 2,574,902, a dilute aqueous solution of sodium silicate is treated with a cation exchange resin to prepare an active silicic acid aqueous solution. A solution (seed solution) in which silica seed particles are dispersed is created by adding sodium silicate as an alkali to stabilize a part of this active silicic acid aqueous solution and polymerizing it, while maintaining the alkaline conditions. A method is disclosed in which the rest of the silicic acid aqueous solution (feed liquid) is gradually added to polymerize silicic acid to grow particles of colloidal silica.

When producing colloidal silica, the most industrially used production method is the above-mentioned ion exchange resin method. By this method, it is possible to produce colloidal silica having a sharp particle size distribution while freely controlling the particle size using an alkali metal silicate, such as water glass, which is an inexpensive industrial product, as a raw material. Has become. Most of the colloidal silica obtained by these methods are spherical particles, and the particle diameter is several n.
Those of m to several hundred nm are commercially available. The particle size of the colloidal silica used is not particularly limited, but inexpensive particles having a particle size of 7 nm to 50 nm can be used.

The compounding ratio of colloidal silica is the specific resin / colloidal silica = 90/10 to 20 in terms of mass.
/ 80 is preferable, and more preferably 50/50 to 30 /
70. When the content of colloidal silica is less than 10%, the contribution of colloidal silica to improving the coating film strength is reduced. If the content of colloidal silica exceeds 80%, the film formability may be insufficient, and cracks may occur in the undercoat layer.

The coating method of such an undercoat layer is not particularly limited, but various coating apparatuses which are usually used, for example, bar coater, roll coater, blade coater, air knife coater, gravure coater, die coater, curtain. A coater, a cast coater, etc. can be used.

The support used in the present invention includes high-quality paper, medium-quality paper, coated paper, art paper, cast-coated paper,
Sheets generally used as a support for the inkjet recording material such as paperboard, synthetic resin laminated paper, metal vapor deposition paper, synthetic paper, and white film can be used, but are not limited thereto. In particular, when a support sheet having a smooth surface and relatively low liquid absorption, such as synthetic resin laminated paper, metal vapor-deposited paper, synthetic paper, and white film, is used, a means such as a film transfer method or cast coating is used. Even if it is not used, a very high gloss ink receiving layer can be obtained, which is preferable. In addition, polyethylene terephthalate on the support,
If a plastic film with excellent transparency such as polyvinyl chloride, polycarbonate, polyimide, cellulose triacetate, cellulose diacetate, polyethylene, polypropylene is used, back print or OHP
An inkjet recording material that can be used as a light-transmissive recording medium such as a sheet can be produced. The particle size is 1
A combination of an ink receiving layer using a fine pigment having a particle size of not more than μm, preferably not more than 800 nm increases the transparency of the entire recording material, and can be suitably used for these media.

When the adhesion between these supports and the undercoat layer formed on the surface is insufficient, corona discharge treatment,
A plasma discharge treatment, an ultraviolet ray irradiation treatment, an active energy ray irradiation treatment such as an electron beam, and an easy adhesion treatment such as a flame treatment can be performed. It is also possible to perform these treatments on the undercoat layer.

The thickness of the support is adjusted according to the conditions of use of the recording medium and is not particularly limited. However, it is 50 to 500 .mu.
m is preferred. Further, the opacity of the support is not particularly limited, but when the silver salt photographic tone is particularly desired, the opacity measured according to JIS P8138 is preferably 85% or more, and more preferably Is preferably 93% or more.

The ink receiving layer of the ink jet recording material of the present invention is irradiated with an electron beam while containing a solvent. The main component of the solvent contained in this paint is water, but various solvents can be added as subcomponents. In that case, methanol, ethanol, isopropyl alcohol, butanol, acetone, toluene, xylene, dioxane, acetonitrile, methyl ethyl ketone, ethyl acetate and the like, which have a relatively low boiling point, are preferably used, but not limited thereto. Also, two or more kinds of these solvents may be mixed and used.

As the electron beam-curable component used in the present invention, when it is irradiated with an electron beam in a state of being dissolved or dispersed in a water-based coating composition, a reaction such as a polymerization reaction or a cross-linking reaction in which the molecular weight increases is caused to cause a coating composition. The type is not particularly limited as long as it is a substance having a property of hydrogelating. As an example, there is a polymer or oligomer having an acryloyl group or a methacryloyl group at the molecular end or side chain, which is generally called electron beam curable resin,
Among them, there are polyester type, polyurethane type, polyepoxy type, and polyether type, and any of them can be used. Also, a monomer containing a plurality of acryloyl groups or methacryloyl groups in one molecule can be used, and may be used as a mixture with the above electron beam curable polymer or oligomer.

In addition, a hydrophilic resin which does not have a radical-polymerizable unsaturated bond but forms a hydrogel by irradiating an aqueous solution with an electron beam can also be used as an electron beam-curable component. Specific examples thereof include fully saponified polyvinyl alcohol, partially saponified polyvinyl alcohol, polyethylene oxide, polyalkylene oxide, polyvinylpyrrolidone, water-soluble polyvinyl acetal, poly-N-vinyl acetamide, polyacrylamide, polyacryloylmorpholine, polyhydroxyalkyl acrylate. , Polyacrylic acid, hydroxyethyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, hydroxypropyl cellulose, gelatin, casein and water-soluble derivatives thereof, but are not limited thereto. As the water-soluble derivative, a cation-modified product, an anion-modified product, a derivative obtained by chemically modifying a functional group such as a hydroxyl group, a carboxyl group, or an amino group by esterification, etherification, or amidation, or another side chain by graft polymerization is used. The introduced polymer can be exemplified. Further, it may be a copolymer containing the constitutional unit of each resin. For example, polyvinyl alcohol, polyvinylpyrrolidone, water-soluble polyvinyl acetal, poly-N
Examples of the copolymer include vinyl monomers constituting vinylacetamide, polyacrylamide, polyacryloylmorpholine, polyhydroxyethyl acrylate, polyacrylic acid, and copolymers containing these monomers and other monomers. Further, these resins can be used not only alone but also as a mixture of two or more kinds. Since these resins are general-purpose resins, they are inexpensive, weakly irritating to the skin, and the strength of the gel obtained after electron beam irradiation can be easily adjusted by selecting the molecular weight, making them suitable as electron beam curable components. Used. Another point is that it is more hydrophilic than the electron beam curable polymers, oligomers and monomers containing an acryloyl group or methacryloyl group. Among these resins, polyvinyl alcohol is particularly preferably used because it is easy to handle and has a wide variety of types. Even when these water-soluble resins are used, the resins are crosslinked by electron beam irradiation to form a three-dimensional network, and thus the obtained ink jet recording material has extremely high water resistance.

When the above-mentioned specific hydrophilic resin is used as the electron beam-curable component, the optimum value of the molecular weight cannot be generally stated because the properties vary depending on the type of resin. It may cause a problem in workability. On the contrary, if the molecular weight is too low, the gel strength of the hydrogel obtained by electron beam irradiation may be insufficient, which may cause cracking of the coating film after drying, which may hinder the appearance of the recording material. . The molecular weight is preferably about 10,000 to 5,000,000, and more preferably 50,000 to 1,000,000.

Since dyes and pigments which are coloring components in inks used in ink jet printers often have anionic groups, it is desirable to add a cationic ink fixing agent to the ink receiving layer. Therefore, it is preferable to use a cationic one as the electron beam curable component of the present invention because it functions as an ink fixing agent. For example, cationic polyvinyl alcohol, cationic polyvinylpyrrolidone, cationic water-soluble polyvinyl acetal, cationic poly-N-vinyl acetamide, cationic polyacrylamide, cationic polyacryloylmorpholine, cationic polyhydroxyalkyl acrylate, cationic hydroxyethyl cellulose, Examples thereof include cationic methyl cellulose, cationic hydroxypropyl methyl cellulose, cationic hydroxypropyl cellulose, cationic gelatin, cationic casein and the like. When a large amount of the ink fixing agent is added to the surface layer portion of the ink receiving layer, it is effective for color development and water resistance of the ink. Therefore, when an ink receiving layer having a multi-layered structure is produced using the present invention, it is particularly preferable to provide a layer containing the above-mentioned cationic electron beam-curable component as an upper layer.

In the present invention, it is preferable that the coating layer which is irradiated with the electron beam contains a pigment because the strength of the hydrogel obtained after the irradiation with the electron beam becomes high. In particular, when a porous ink-receiving layer is prepared using a paint whose main component is a fine pigment having a small particle size and a large pore volume, it is possible to quickly absorb the ink and record a fine image due to the capillary phenomenon. Therefore, it is very preferable. The type of pigment used in the paint is not particularly limited, but commercially available pigments,
For example, silica, aluminosilicate, zeolite, kaolin, clay, calcined clay, zinc oxide, tin oxide, aluminum hydroxide, boehmite, pseudoboehmite, alumina,
Calcium carbonate, satin white, aluminum silicate,
Smectite, magnesium silicate, magnesium carbonate,
Examples thereof include various pigments known in the field of general coated paper such as magnesium oxide, diatomaceous earth, styrene-based plastic pigments, urea resin-based plastic pigments, and benzoguanamine-based plastic pigments. Among these pigments, silica, aluminum hydroxide, boehmite, pseudo-boehmite, alumina and the like, which have a large pore volume and are excellent in ink absorbability, are preferably used particularly when an ink receiving layer is produced. When the ink receiving layer is formed, the average particle diameter of the pigment is 1 μm or less, preferably 800 n.
When it is m or less, an ink receiving layer having excellent ink absorbability, transparency, and glossiness can be obtained, which is more preferable. Here, the average particle size is a particle size measured by the dynamic light scattering method (a value obtained by the cumulant method).

Especially, silica is most suitable for use as an ink receiving layer because of its large pore volume. As silica, there are wet method silica prepared from an alkali silicate salt and dry method silica which decomposes a volatile silicon compound such as silicon tetrachloride in a flame, both of which are preferred. The volume of pores of suitable silica having a pore diameter of 100 nm or less is 0.4 to 2.5 ml /
It is g. Although colloidal silica can be used, as can be seen from the manufacturing method, colloidal silica has a pore size of 100 because the silica particles do not form secondary particles.
The pore volume of nm or less is in the range of 0.2 to 0.3 ml / g, and the ink absorption amount may be small for use in the ink receiving layer.

In order to obtain an ink receiving layer having high gloss and high transparency, it is preferable to use a fine pigment having an average particle diameter of 1 μm or less. Among them, the fine pigment has an average particle diameter of 3 to 60 n.
average particle size of 20 to 800 nm formed by agglomeration of primary particles of m
It is more preferable that the secondary particles are In particular, the particle size of the secondary particles is preferably 30 to 700 nm, more preferably 4
It is 0 to 500 nm. Since such secondary particles have voids inside the secondary particles, the pore volume is large. Furthermore, since the voids between the secondary particles can also be used for absorbing ink, the ink absorbing capacity is high. Further, since the primary particles are sufficiently smaller than the wavelength of light, there is an advantage that the light-scattering ability is smaller and the transparency of the ink receiving layer is higher than that of a pigment that does not form secondary particles. If the primary particle size or the secondary particle size of the pigment is too small, it becomes difficult to form voids that contribute to ink absorption, and thus the ink absorbability of the receiving layer may be poor. On the other hand, if the primary particle diameter or the secondary particle diameter is too large, the transparency of the recording layer is lowered, and it may be difficult to obtain a high print density. On the other hand, if the secondary particle size is too large, not only the gloss of the receiving layer may be lowered, but also the surface may be roughened or powder may fall off. The primary particle diameters of the pigments used in the present invention are all particle diameters (Martin diameters) observed with an electron microscope (SEM and TEM) (see "Fine Particle Handbook", Asakura Shoten, p52). The secondary particle size is the particle size measured by the dynamic light scattering method.

Further, in order to obtain an ink receiving layer having a high ink absorbing ability, it is preferable that the fine pigment used has a high pore volume, but 0.4 to 2.5 ml / g is preferable, and more preferably 0. 5 to 2.0 ml / g, more preferably 0.6 to 1.9 ml / g, and most preferably 0.7.
~ 1.8 ml / g. This pore volume is a value obtained by using a specific surface area / pore distribution measuring device by a gas adsorption method, and is a total pore volume of pores having a pore diameter of 100 nm or less.
As described above, silica, aluminum hydroxide, boehmite, pseudo-boehmite, and alumina are preferable, and secondary particles may be formed.

The method for producing these fine pigments is not particularly limited, but as one of the means therefor, commercially available pigments (several μm to
A method of pulverizing and dispersing by giving a strong force to a few tens of μm) by a mechanical means. That is, breath
It is obtained by the king down method (method of subdividing a lump material). As the mechanical means, an ultrasonic homogenizer, a pressure homogenizer, a nanomizer, a high-speed rotary mill, a roller mill, a container drive medium mill,
Mechanical methods such as a medium stirring mill, a jet mill and a sand grinder can be used. The obtained fine pigment may be in the form of colloid or slurry. As another preferable method for producing a fine pigment, JP-A-5-3241 is known.
Examples thereof include a method of hydrolyzing a metal alkoxide disclosed in Japanese Patent Application Laid-Open No. 3 and Japanese Patent Application Laid-Open No. 7-76161.

The most preferable fine pigment is produced by condensing activated silicic acid and has an average secondary particle diameter of 1 μm or less and a pore volume of 100 nm or less and a pore volume of 0.4 to 2.5 ml /.
g, preferably 0.4-2.0 ml / g fine silica. As such fine silica, Japanese Patent Laid-Open No. 2001-3
The fine silica disclosed in Japanese Patent No. 54408 is preferable. The method by condensation of activated silicic acid disclosed in Japanese Patent Laid-Open No. 2001-354408 can directly produce fine silica having the above-mentioned particle size and pore volume without using mechanical means, and has a particle size distribution. Since it is narrow, the transparency and gloss of the ink receiving layer are good, so that it can be preferably used in the present invention. Here, the activated silicic acid means, for example, an acidic silicic acid aqueous solution having a pH of 4 or less, which is obtained by subjecting an alkaline metal silicate aqueous solution to an ion exchange treatment with a hydrogen type cation exchange resin. The SiO ₂ concentration is preferably 1 to 6% by mass, more preferably 2 to 5% by mass and pH 2 to
An activated silicic acid aqueous solution of 4 is desirable. The alkali metal silicate may be one that can be obtained as a commercially available industrial product, and more preferably, sodium water glass having a SiO ₂ / M ₂ O (where M represents an alkali metal atom) molar ratio of about 2 to 4 is used. It is preferably used. As a method for condensing activated silicic acid, an activated silicic acid aqueous solution is dropped into hot water, or
The activated silicic acid aqueous solution is heated to generate seed particles, and an alkali is added to stabilize the seed particles (aggregated particles) before the dispersion liquid precipitates or gels. It is preferable that the seed particles are grown by adding the aqueous silicic acid solution to SiO ₂ contained in the seed particles at a rate of 0.001 to 0.2 mol / min in terms of SiO ₂ . The average secondary particle diameter is preferably 1 μm or less, more preferably 20 nm to 8
00 nm, most preferably 30 nm to 700 nm. When the particle size exceeds 1 μm, light scattering increases, and when used in the ink receiving layer, high printing density cannot be obtained. This average secondary particle diameter is a value measured by a particle size meter adopting the dynamic light scattering method and analyzed by the cumulant method.

The primary particle diameter is not particularly limited, but the diameter is preferably 5 nm to 60 nm. However,
Since the primary particles of the fine silica are chemically bonded to form secondary particles, it is difficult to accurately determine the diameter of the primary particles. When this order to adopt a specific surface area measured by the nitrogen adsorption method as a measure of the average particle diameter of primary particles, preferred specific surface area of 50m ² / g~500m ² / g. When the specific surface area is smaller than this range, the light scattering becomes strong, the transparency of the dried coating film may decrease, and the printing density may decrease. On the other hand, when the specific surface area is larger than the above range, the coating liquid is likely to cause gelation, which may impair workability. Further, when mixed with a binder to form a dry coating film, cracking is likely to occur, and it may be difficult to obtain a good coating film. More preferably 100m ² / g~400m ² / g, more preferably from 150m ² / g~350m ² / g. In the case of non-aggregated true spherical silica particles, the primary particle diameter (nm)
= 2720 / specific surface area (m ² / g), but this relationship holds approximately even in the case of aggregated particles.

The mixing ratio of the fine pigment and the electron beam curable component is
1 part of electron beam curable component is added to 100 parts by mass of fine pigment.
It is preferable to mix them in an amount of 100 parts by mass. As described above, the electron beam curable component does not have a radical-polymerizable unsaturated bond, but a hydrophilic resin that forms a hydrogel by irradiating an aqueous solution with an electron beam is preferable. From the viewpoint of ink absorption, it is desirable to control the electron beam curable component to a minimum amount. Further, since the electron beam curable component may adhere to the periphery of the fine pigment in the receiving layer to increase the apparent particle size, the electron beam curable component also causes cracks from the viewpoint of transparency of the receiving layer. It is better to have less than the range. For the above reasons, the compounding ratio of the pigment and the electron beam curable component is more preferably 3 to 30 parts by weight, and most preferably 5 to 25 parts by weight with respect to 100 parts by weight of the fine pigment. is there.

The ink receiving layer has a pore volume of 0.2 to 2.0.
It is preferable to adjust the concentration within the range of ml / g. This value is adjusted by selecting the fine pigment having an appropriate pore volume as described above and the addition amount of the electron beam curable component. The pore volume of the ink receiving layer is 0.2 ml /
If it is less than g, the ink cannot be absorbed unless the coating amount is increased, so that the inkjet recording material becomes bulky and the manufacturing cost becomes high. On the other hand, if the pore volume exceeds 2.0 ml / g, the mechanical strength of the ink receiving layer decreases, and the receiving layer is easily scratched, peeled off, or cracked, which is not preferable. The pore volume is a value obtained by using a specific surface area / pore distribution measuring device by a gas adsorption method, and the pore diameter is 100
It is the total pore volume of pores of nm or less.

The preferred solid content concentration of the coating material used in the present invention varies greatly depending on the composition of the coating material, but it is preferably a higher concentration within the range where the coating material is stable and coatable. This is because the higher the concentration of the coating, the higher the efficiency of the crosslinking reaction that progresses by electron beam irradiation, so the strength of the coating layer after gelation increases and the adhesion stability with the support improves. Further, when the coating layer contains a pigment, the effect of preventing cracking is enhanced, which is preferable. Needless to say, there is also an advantage that the drying load is light. However, in practice, the upper limit of the concentration is often determined in terms of the viscosity and stability of the paint. Considering the above points, the solid content concentration of the coating material is preferably 3 to 40% by weight, more preferably 5 to 25% by weight.

In addition to the main component, other components can be added to the coating material of the ink receiving layer. These additives themselves may not be electron beam curable components. An example thereof is a cationic resin. The type of cationic resin is also not particularly limited, but for example, N, N-
Dimethylaminoethyl acrylate quaternary compound, N, N-
Dimethylaminoethyl methacrylate quaternary compound, N, N
-A resin containing a structural unit having a cationic property such as dimethylaminopropylacrylamide quaternary compound, vinylimidazolium metochloride, diallyldimethylammonium chloride, methyldiallylamine salt, monoallylamine salt, diallylamine salt and the like. In addition, a cationic resin containing a dicyandiamide / polyalkylenepolyamine condensate, a secondary amine / epichlorohydrin addition polymer, a polyepoxyamine, or the like can also be used. It is also possible to mix an inorganic salt, an organic salt, an alumina sol or the like as the cationic substance. The addition of a cationic substance improves the water resistance storage stability of the print.

In addition, a defoaming agent may be added to the coating composition to improve workability at the time of coating, or a surfactant may be added to enhance adhesion to the undercoat layer. Starch and synthetic resin particles may be mixed in order to prevent sticking of the recording material and to improve the paper passing property. In addition, various pigments other than the main component may be added to adjust transparency and surface gloss, and for example, a light resistance improver such as an ultraviolet absorber or a light stabilizer may be added to improve the storage stability of a printed image. It can also be added.

As a method of adding these additives, they may be mixed in advance with the coating material, or a coating layer may be first formed and then a solution containing the additive may be overcoated, sprayed or impregnated. It may be added later. When the additive is added to the paint in advance, when the paint gels due to the shock of addition, it is also an effective means to redisperse it by using a mechanical means. For example, if a cationic resin is added to a dispersion liquid of an anionic pigment such as silica, the coating will temporarily gel because of the electrostatic characteristics of both, but coating is possible if redispersed using mechanical means. Since both are strongly bound electrostatically in the dried coating film, the water resistance of the coating film can be sufficiently maintained even if the water-soluble cationic resin is not particularly crosslinked.

In the ink jet recording material of the present invention, at least one ink receiving layer is formed on a support having a specific undercoat layer in a state containing an electron beam curable component and a solvent, and is irradiated with an electron beam. After that, it is dried.
That is, the upper layer and the outermost layer may be provided by a normal coating method (that is, a method of immediately drying after coating), or the coating step and the electron beam irradiation step may be repeated several times to form an ink receiving layer in multiple layers. May be. Further, before the electron beam irradiation step, preliminary drying may be performed in order to evaporate a part of the solvent contained in the coating layer. However, if you want to maximize productivity, directly form the ink receiving layer on the undercoat layer by single-layer or simultaneous multilayer coating, irradiate the electron beam, and then collectively coat the coating layers. The method of drying by drying is most preferable from the viewpoint of cost and adhesion of each layer.

A known coating device is used for coating the ink receiving layer,
For example, a bar coater, a roll coater, a blade coater, an air knife coater, a gravure coater, a die coater, a curtain coater, a cast coater, or the like can be used, but the present invention is not limited thereto. Further, when the ink receiving layer is multi-layered for the purpose of high functionality, single layer coating may be repeated, but a dedicated multi-layer slot die coater, multi-layer slide die coater, multi-layer curtain coater, etc. Simultaneous multilayer coating may be performed using a simultaneous multilayer coating device.

The coating amount of the ink receiving layer varies greatly depending on the intended use of the recording medium and is not particularly limited, but
The total coating amount of all layers after drying is 1 to 80 g / m ^{2 by} weight.
The degree is preferably about 3 to 60 g / m ² . If the coating amount is too large, curling is likely to occur and the cost is increased, which is not preferable. Further, there is a possibility that the entire layer cannot be gelled sufficiently. If the coating amount is less than 1 g / m ² , the ink absorption may be insufficient. The ink receiving layer may be on one side or both sides of the support, and in the case of both sides, the layer constitution may be different. The coating amount of each layer in the case of multilayer coating is not particularly limited, but if it is too small, it becomes difficult to control the coating amount.

As the electron beam irradiation method in the present invention, for example, a scanning method, a curtain beam method, a broad beam method, etc. are adopted, and an accelerating voltage at the time of irradiating the electron beam is preferably about 50 to 300 kV. The irradiation dose of the electron beam is preferably adjusted within the range of about 1 to 200 kGy. If it is less than 1 kGy, the coating layer may be insufficiently gelled, and if it exceeds 200 kGy, the support or the coating layer may be deteriorated or discolored.

The ink jet recording material of the present invention has very high water resistance. Originally, even when a water-soluble resin is used as a binder resin, the resin is cross-linked by electron beam irradiation to form a three-dimensional network, and thus the obtained ink jet recording material is hardly dissolved even when immersed in water. When printing is performed on this recording medium, the resin cross-linked body portion also swells by absorbing ink in the ink receiving layer and expands in volume, but the swelling speed is higher than the ink absorbing speed due to the capillary phenomenon of the entire ink receiving layer. Since it is slow, the speed of ink absorption, which is an advantage of the pigment-based receiving layer, is not impaired.

Further, a coating sheet having an ink receiving layer formed on a temporary support is prepared, a true support is attached thereon, and then the temporary support is peeled off and removed. It is also possible to make a recording body in which the surface shape of the support is copied. If the surface of the temporary support is smooth and has a high gloss, the ink receiving layer also has a very high gloss and has a high-grade feeling. The step of attaching to the true support may be performed before or after drying the coating layer. Any known adhesion method may be used, and either dry lamination or wet lamination may be used. In addition, before drying, there is a case where the adhesive can be adhered by simply pressing the support and drying it without using an adhesive. As the temporary support, a metal roll or a resin film such as a PET film can be preferably used.

[0053]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified,% representing concentration in this example means mass percent, and parts means parts by mass.

[Measurement Method of Pore Volume and Pore Diameter of Fine Pigment] An aqueous dispersion of fine pigment was dried at 105 ° C., and the pore volume and the pore size distribution of the obtained powder sample were measured by gas adsorption method ratio. Surface area / pore distribution measuring device (SA31 manufactured by Coulter)
00 plus type) was used as a pretreatment, and then degassed in vacuum at 200 ° C. for 2 hours, and then measured. Nitrogen was used as the adsorption gas. As the pore volume, the value of the total pore volume (Total Pore Volume) of pores having a pore diameter of 100 nm or less was used. The pore diameter was defined as the maximum volume fraction pore diameter in the pore distribution curve obtained from the analysis of the desorption isotherm by the BJH method.

[Measurement Method of Average Secondary Particle Diameter of Fine Pigment] 100 ml of an aqueous dispersion of fine pigment was placed in a stainless steel cup having a capacity of 500 ml and manufactured by T.K. K. Dispersion treatment using a homodisper (3000 rpm, 5 minutes)
Then, the tertiary particles in the aqueous dispersion were pulverized and dispersed. The dispersion liquid after the treatment was sufficiently diluted with distilled water to prepare a sample liquid, and a laser particle size meter (manufactured by Otsuka Electronics Co., Ltd., LPA3) by a dynamic light scattering method was used.
000/3100) was used to measure the average particle size. As the average particle diameter, the value calculated from the analysis using the cumulant method was used.

[Method for producing cationic silica sol A (dispersion)] (Preparation of active silicic acid aqueous solution) SiO ₂ concentration 30%, Si
O ₂ / Na ₂ O molar ratio of 3.1 sodium silicate solution (Co., Ltd.)
Tokuyama, No. 3 sodium silicate) mixed with distilled water, Si
A dilute aqueous solution of sodium silicate having an O ₂ concentration of 4.0% was prepared.
This aqueous solution was passed through a column packed with a hydrogen type cation exchange resin (manufactured by Mitsubishi Chemical Corporation, Diaion SK-1BH) to prepare an active silicic acid aqueous solution. The obtained active silicic acid aqueous solution had a SiO ₂ concentration of 4.0% and a pH of 2.9.

(Preparation of seed solution) In a 5 liter glass reaction vessel equipped with a reflux condenser, a stirrer and a thermometer, 500
g of distilled water was heated to 100 ° C. This hot water is 100 ℃
While maintaining the above, a total of 450 g of the above active silicic acid aqueous solution was added at a rate of 1.5 g / min to prepare a seed solution. The physical properties of the seed particles (aggregated particles) in this seed solution were an average secondary particle diameter of 184 nm, a specific surface area of 832 m ² / g, a pore volume of 0.60 ml / g, and a pore diameter of 4 nm.

(Preparation of Fine Silica Dispersion) 0.015 mol of ammonia was added to 950 g of the above seed solution to stabilize it in the glass reaction vessel, and the mixture was heated to 100 ° C. A total of 550 g of the above active silicic acid aqueous solution was added to this seed liquid at a rate of 1.5 g / min. After the addition of the activated silicic acid was completed, the solution was kept at 100 ° C. and refluxed for 9 hours to obtain a fine silica dispersion. The dispersion was a bluish transparent solution and had a pH of 7.2. The properties of this fine silica (aggregated particle) dispersion were an average secondary particle diameter of 130 nm, a specific surface area of 257 m ² / g, a pore volume of 1.0 ml / g, and a pore diameter of 16 nm. This dispersion was concentrated with an evaporator to a silica concentration of 11%.
100 parts of this dispersion was added to diallyldimethylammonium chloride / acrylamide copolymer (Nitto Boseki Co., Ltd.).
Made, trade name: PAS-J-81) 10% 11% aqueous solution was added, and a hydraulic ultra-high pressure homogenizer (manufactured by Mizuho Industry Co., Ltd., Microfluidizer M110-E / H).
To produce an aqueous dispersion of cationic silica (cationic silica sol A) having an average particle size of 376 nm. This dispersion has a solid content concentration of 11% and a silica concentration of 1%.
The concentration was 0% and the diallyldimethylammonium chloride / acrylamide copolymer concentration was 1%. In addition, the pore volume was measured in a state of containing the copolymer, and was found to be 0.9 m.
It was 1 / g.

[Method for producing cationic silica sol B (dispersion liquid)] Synthetic amorphous silica having an average particle diameter of 3 μm (manufactured by Nippon Silica Industry Co., Ltd., trade name: Nipsil HD-2, primary particle diameter = 11 nm) is treated with water. After being pulverized and dispersed by a sand grinder, the hydraulic ultrahigh pressure homogenizer used in the method for producing silica sol A (manufactured by Mizuho Industry Co., Ltd.,
Microfluidizer M110-E / H) has an average particle diameter (average secondary particle diameter) of 168 nm measured by the above method.
It was repeatedly pulverized and dispersed until it became, to obtain an 11% aqueous dispersion (silica sol B). When the pore volume of silica in this aqueous dispersion was measured by the above method, it was 1.2 ml / g. To 100 parts of silica sol B was added 10 parts of an 11% aqueous solution of diallyldimethylammonium chloride / acrylamide copolymer used in the method for producing cationized silica sol A as an ink fixing agent, and the gelled mixture was further pulverized and dispersed by the homogenizer to obtain an average. Particle size 422nm
To prepare an aqueous dispersion of cationic silica (cationic silica sol B). This dispersion had a solid content concentration of 11%, a silica concentration of 10%, and a diallyldimethylammonium chloride / acrylamide copolymer concentration of 1%. Further, the pore volume was 1.1 ml / g when the pore volume was measured with the copolymer contained.

[Preparation Method of Ink Receptive Layer Paint] 1. Paint A (cationic silica paint) 100 parts of cationic silica sol A completely saponified polyvinyl alcohol (manufactured by Kuraray Co., Ltd., trade name: PVA-140)
H, degree of polymerization = 4000, degree of saponification = 99% or more) 6%
28 parts of the aqueous solution was mixed to prepare a cationic silica paint having a solid content concentration of 9.9%. 2. Paint B (Cationic Silica Paint) A paint B was prepared in the same manner as the paint A except that the cationic silica sol B was used instead of the cationic silica sol A. 3. Paint C (alumina paint) A hydraulic ultra-high pressure homogenizer used in the method for producing silica sol A after pulverizing a 12% aqueous dispersion of alumina (AKP-G020, γ-alumina manufactured by Sumitomo Chemical Co., Ltd.) with a sand grinder. Alumina sol water having a pore volume of 0.5 ml / g and an average particle diameter (average secondary particle diameter) of 200 nm measured by the above measuring method was prepared. A coating C having a solid content concentration of 9.6% was prepared by mixing 12.5 parts of a 6% aqueous solution of completely saponified polyvinyl alcohol used in the coating A with 100 parts of the alumina sol.

[Production of Support] 1. Sheet A CSF (JIS P-8121) beaten up to 250 ml of conifer bleached kraft pulp (NBKP) and CSF of 2
Hardwood bleached kraft pulp beaten to 80 ml (LBK
P) is mixed at a mass ratio of 2: 8, and the concentration is 0.5%.
A pulp slurry of was prepared. To this pulp slurry, 2.0% of cationized starch, 0.4% of alkyl ketene dimer, 0.1% of anionized polyacrylamide resin and 0.7% of polyamide polyamine epichlorohydrin resin were added to the dry weight of pulp, And stirred to disperse. Paper making with a Fourdrinier machine pulp pulp of the above composition,
Through a dryer, size press, machine calendar,
A base paper having a basis weight of 101 g / m ² and a tightness of 1.0 g / cm ³ was produced. The size press liquid used in the size press step was prepared by mixing carboxyl-modified polyvinyl alcohol and sodium chloride in a weight ratio of 2: 1 and adding the mixture to water to dissolve by heating to a concentration of 5%. A total of 25 ml / m ^{2 of} this size press liquid was applied on both sides of the paper to obtain a sheet A having a smoothness (J.TAPPI No. 5-2) of 380 seconds.

2. Sheet B After performing corona discharge treatment on both sides of Sheet A, the following polyolefin resin composition 1 mixed and dispersed with a Banbury mixer was applied to the felt side of the base paper so that the coating amount was 15 g / m ^2, and The coating amount of the polyolefin resin composition 2 (resin composition for back surface) on the wire side of the base paper is 25
It was coated with a melt extruder having a T-type die (melting temperature 320 ° C.) so as to be g / m ^2, and was cooled and solidified with a cooling roll having a mirror surface on the felt side and a rough surface on the wire side to give an opacity ( JIS P8138) is 93% and the smoothness on the mirror surface side (felt side of the base paper) (J.TAPPI No.
5-2) manufactured a resin-coated sheet B having 26000 seconds. Polyolefin resin composition 1 long-chain low-density polyethylene resin (density 0.926 g / c
m ³ , melt index 20 g / 10 minutes) 35 parts,
Low-density polyethylene resin (density 0.919 g / cm ³ ,
Melt index 2 g / 10 minutes) 50 parts, anatase type titanium dioxide (A-220; made by Ishihara Sangyo) 15 parts, zinc stearate 0.1 part, antioxidant (Irganox)
1010; manufactured by Ciba Geigy) 0.03 part, ultramarine blue (Blue mouth ultramarine No. 2000; manufactured by Daiichi Kasei) 0.09 part, optical brightener (UVITEX OB; manufactured by Ciba Geigy) 0.3 part Polyolefin resin composition 2 high Density polyethylene resin (density 0.954 g / cm ³ ,
Melt index 20 g / 10 min) 65 parts, low density polyethylene resin (density 0.924 g / cm ³ , melt index 4 g / 10 min) 35 parts

<Example 1> A corona discharge treatment was applied to the mirror side (felt side of the base paper) of the sheet B, and a 15% concentration polyester copolymer aqueous resin (Toyobo Co., Ltd.) as an undercoat layer was applied thereon. Product name: Bayronal MD-140
0) was bar-coated so that the coating amount of solid content was 5 g / m ² , and dried at 100 ° C. Onto this, a coating A composed of a cationic silica sol and polyvinyl alcohol was bar-coated so that the coating amount of the solid content was 20 g / m ² , and immediately under an environment of nitrogen gas, an electron beam irradiation device (Electro Curtain manufactured by ESI). Acceleration voltage of 175 kV and irradiation dose of 50
It was irradiated with an electron beam of kGy. Upon touching the coated surface after irradiation, it was found that the paint was a jelly-like solid, which turned into a hydrogel. This was dried with hot air at 110 ° C. to produce the inkjet recording material of the present invention.

<Example 2> The subbing layer contains α-olefin.
Unsaturated carboxylic acid copolymer resin Self-emulsifying aqueous solution (Sumitomo Seika Chemicals Ltd., trade name: Saixen AC, ethylene / acrylic acid = 85 parts / 15 parts ammonia neutralized product copolymer resin) was used. An ink jet recording material was manufactured in the same manner as in Example 1 except for the above.

Example 3 An ink jet recording material was manufactured in the same manner as in Example 1 except that the coating amount of the solid content of the undercoat layer was 0.3 g / m ² .

Example 4 A polyolefin polymer (manufactured by Toho Chemical Industry Co., Ltd., trade name: Hitec E-) was used as the undercoat layer.
Inkjet recording material was manufactured in the same manner as in Example 1 except that (8000) was used.

<Example 5> For 50 parts of the self-emulsifying aqueous solution of the α-olefin / unsaturated carboxylic acid copolymer resin used in Example 2, colloidal silica (Nissan Chemical Industry Co., Ltd.) was used.
Product name: Snowtex N, particle size 10-20n
m, pore volume 0.22 ml / g) was mixed with 50 parts of the undercoat layer coating material having a concentration of 15% and the solid content coating amount was 3 g / m ^2.
An ink jet recording material was manufactured in the same manner as in Example 1 except that the bar coating was performed so that

Example 6 An ink jet recording material was manufactured in the same manner as in Example 1 except that the sheet A was used as a support and the solid coating amount of the undercoat layer was 20 g / m ² .

<Example 7> 50 parts of the polyester copolymer aqueous resin used in Example 1 was mixed with 50 parts of colloidal silica (Nissan Chemical Co., Ltd., trade name: Snowtex N). An ink jet recording material was manufactured in the same manner as in Example 6 except that the adjusted undercoat layer coating material having a concentration of 15% was bar-coated so that the solid content was 15 g / m ² .

<Example 8> A coated sheet was produced in the same manner as in Example 5 except that the paint B was used instead of the paint A. On top of that, paint A at a solid coating amount of 3 g / m ²
And then immediately dried with hot air at 110 ° C. to produce an inkjet recording material.

<Example 9> A coated sheet was produced in the same manner as in Example 5 except that the coating material B was used in place of the coating material A. On top of that, paint C at a solid coating amount of 3 g / m ²
And then immediately dried with hot air at 110 ° C. to produce an inkjet recording material.

Comparative Example 1 An ink jet recording material was manufactured in the same manner as in Example 1 except that the undercoat layer was not provided and the corona discharge treatment was not performed.

Comparative Example 2 An ink jet recording material was manufactured in the same manner as in Example 6 except that the undercoat layer was not provided and the corona discharge treatment was not performed.

Comparative Example 3 Example 1 was repeated except that an aqueous acrylic copolymer resin resin (manufactured by Clariant Polymer Co., Ltd., trade name: Movinyl 735) was used as the undercoat layer.
An ink jet recording material was manufactured by the same method as described above.

<Comparative Example 4> As an undercoat layer, styrene
An inkjet recording material was manufactured in the same manner as in Example 1 except that an acrylic ester copolymer resin aqueous resin (manufactured by Nippon NSC Ltd., trade name: Iodosol GD59) was used.

<Comparative Example 5> As an undercoat layer, a completely saponified polyvinyl alcohol aqueous solution (manufactured by Kuraray Co., Ltd., trade name:
PVA-140H, degree of polymerization = 4000, degree of saponification = 99
% Or more), an ink jet recording material was manufactured in the same manner as in Example 1.

Comparative Example 6 An ink jet recording material was manufactured in the same manner as in Example 1 except that the electron beam irradiation was not performed.

Table 1 shows the quality evaluation results of ink jet recording materials manufactured by the methods described in Examples and Comparative Examples. The visual appearance, 75 ° gloss, and pore volume of the ink receiving layer were evaluated by the following methods.

Evaluation Method of Inkjet Recording Material [Evaluation of Visual Appearance of Coating Sheet] An inkjet printer (PM-90 manufactured by EPSON) was used as an inkjet recording material.
0C) PM photo paper recommended setting print mode, ISO-
After printing 400 images ("high-definition color digital standard image data ISO / JIS-SCID", p13, image name: fruit basket), the visual appearance was evaluated in the following 5 grades. 5 points: The coating film is excellent in smoothness and glossiness and has a glossy silver salt photographic appearance. 4 points: The smoothness and gloss of the coating film are slightly inferior to those of the glossy silver salt photographic tone, but good. 3 points: Some roughness is felt on the surface of the coating layer. Therefore, it feels less glossy than the upper level. 2 points: Roughness of the surface of the coating layer is clear, and therefore the glossiness is low. 1 point: In addition to the large roughness of the surface of the coating layer, the unevenness of the coating layer due to the influence of the surface property of the support and the shrinkage during drying is clear, and the quality is low.

[75 ° gloss] 7 of ink jet recording material
The 5 ° gloss was measured according to JIS standard P8142.

[Pore Volume of Ink Receiving Layer] The ink receiving layer of the coated sheet was scraped off with a cutter knife to obtain a sample. When the ink receiving layer has a two-layer structure, the first layer (lower layer)
The sample of the second layer (upper layer) was carefully collected so as not to mix. This sample is a gas adsorption specific surface area / pore distribution measuring device (SA3100Plus type manufactured by Coulter)
Was measured as a pretreatment by degassing under vacuum at 150 ° C. for 2 hours. Pore volume is the total pore volume of pores with a diameter of 100 nm or less (Total Pore Volume)
The value obtained from the adsorption isotherm was used. However, when the ink receiving layer was extremely cracked or peeled during the drying, it was impossible to obtain a standard sample, and therefore it could not be measured.

[0082]

[Table 1]

[0083]

[Table 2]

As is clear from Examples 1 to 9 in Tables 1 and 2, when a specific undercoat layer is used, an ink jet recording material excellent in visual appearance and gloss can be produced. On the other hand, when there is no undercoat layer or when the undercoat layer is provided with other materials, the visual appearance and gloss are insufficient, and it is not suitable for printing full-color photographs as a substitute for silver halide photographs. (Comparative Examples 1-5). In Comparative Example 6, the ink receiving layer was provided by drying without irradiating the electron beam, but the ink receiving layer was peeled off because of significant cracking. The gloss was also extremely low.

[0085]

According to the present invention, it is possible to provide a high-quality inkjet recording material which is excellent in visual appearance and glossiness and is suitable for printing a full-color photograph.

Claims (6)

[Claims] 1. An inkjet recording material having one or more ink receiving layers on a support, wherein a polyolefin polymer, an α-olefin / unsaturated carboxylic acid copolymer, and a polyester copolymer are provided on the support. An aqueous coating composition having an undercoat layer containing at least one selected from the group consisting of an ink receiving layer in contact with the undercoat layer and containing an electron beam curable component which forms a hydrogel by irradiating an aqueous solution with an electron beam. An ink jet recording material, which is an ink receiving layer formed by applying the above composition, irradiating with an electron beam to hydrogel the applied layer, and then drying. 2. The ink jet recording material according to claim 1, wherein the undercoat layer contains colloidal silica. 3. The coating amount of the solid content of the undercoat layer is 0.1 to 30.
The inkjet recording material according to claim 1 or 2, which has g / m ² . 4. At least one ink receiving layer formed by irradiating an electron beam to hydrogel the coating layer and then drying the coating layer contains a fine pigment having an average particle diameter of 1 μm or less,
Total pore volume of pore diameter 100 nm or less is 0.2 to 2.0 m
The inkjet recording material according to any one of claims 1 to 3, which is a porous ink receiving layer of 1 / g. 5. An electron beam-curable component that forms a hydrogel by irradiating an aqueous solution with an electron beam is polyvinyl alcohol, polyethylene oxide, polyalkylene oxide, polyvinylpyrrolidone, water-soluble polyvinyl acetal, poly-N-vinyl acetamide. , Polyacrylamide, polyacryloylmorpholine, polyhydroxyalkyl acrylate, polyacrylic acid, hydroxyethylcellulose, methylcellulose, hydroxypropylmethylcellulose, hydroxypropylcellulose, gelatin, casein, and at least one hydrophilic selected from the group consisting of water-soluble derivatives thereof. The inkjet recording material according to claim 1, which is a hydrophilic resin. 6. The inkjet recording material according to claim 4, wherein the fine pigment is at least one selected from the group consisting of silica, aluminum hydroxide, boehmite, pseudoboehmite, and alumina.