JPH11147361A - Ink jet recording body and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To have a superior ink absorbing property, and an excellent luster property, printing density, or the like by carrying out ink jet printing to a layer having cracks in a lower layer except a surface layer to be recorded, and recognizing cracks on printing dots having predetermined % or more as printing dots formed having a predetermined diameter is observed through a magnification of predetermined times. SOLUTION: By the use of an ink jet recording body, 100-200 pieces of dots per every 1 mm<2> (the size of one dot is about 50 μ) are printed equally at 10 places selected from the recording body for arbitrary ten places by an ink jet printer (for example, PM-700C made by EPSON company) of 720 dpi ×720 dpi. Also, a magnified observation is executed through 100-200 times (for example, 150) by an optical microscope, and if cracks are observed in 30% or more dots, it is determined to have cracks, and if cracks are not observed in 30% or more dots, it is determined not to have cracks. When cracks are observed for a lower layer, all layers on the lower layer are cut off for observation, or the interlayer of cracks is cut up for permitting the surface to be observed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording medium, and more particularly to an ink jet recording medium having excellent ink absorption speed, ink absorption capacity, print density, print gloss, and print quality.

[0002]

2. Description of the Related Art An ink jet recording system is a system in which ink droplets ejected from a nozzle at a high speed are adhered to a recording material for recording, and has features such as easy full-color printing and low printing noise. . In this method, since the ink used contains a large amount of solvent, it is necessary to use a large amount of ink in order to obtain a high recording density. In addition, since the ink droplets are continuously ejected, the next droplet is ejected before the first droplet is absorbed, which is likely to cause a disadvantage that the ink droplets are fused and ink dots are joined. Therefore, the recording medium used in the ink jet recording method has a high print dot density, a bright and vivid color tone, and has a high ink absorption, and does not have ink bleeding even when the print dots overlap. Etc. are required.

[0003] In order to solve these problems, many ink jet recording media having a support surface provided with a coating layer containing a pigment having absorptivity such as silica or alumina and a binder are commercially available. These inks have the disadvantage that the ink absorption speed is slow and printing unevenness and bleeding tend to occur. Further, in such a recording medium, the absorption capacity of the recording layer is relatively small, and at present, a large amount of ink is absorbed by a support (paper or the like). When the ink is absorbed by the support, the recording medium easily undulates and not only affects the print quality,
The disadvantage is that the appearance is poor. In addition, since the pigment used is on the order of several microns, the surface is rough and it is difficult to obtain printed gloss.

In order to solve these problems, in particular, an increase in the ink absorption speed, there has been proposed an ink jet recording medium provided with a recording layer having an irregular crack in the surface layer (for example, JP-A-8-104054 and JP-A-8-104054). −20743
4). If the surface layer has cracks, the absorption rate of the surface layer becomes higher than that of the lower layer, and there is no problem when the ink discharge amount is small, but when the ink discharge amount is large (to obtain a high density and high delicate image). The ink absorbed by the surface layer may not be able to penetrate into the lower layer in time, and the dye may easily accumulate between the surface layer and the lower layer, and the image quality may be degraded. Especially in the case of gloss type, if there are many cracks on the surface, the gloss tends to decrease,
It is difficult to obtain a high gloss equivalent to a photograph.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a high gloss ink jet recording medium having a higher ink absorption speed, a higher ink absorption capacity, a higher printing density. I have.

[0006]

According to the present invention, as a result of diligent studies to solve the above-mentioned problems, the number of recording layers is increased to two or more, and the number of recording layers in the lower layer other than the surface layer (the layer farthest from the support) is reduced. It has been found that the above problem can be solved by forming a crack in at least one layer. When at least one recording layer has a crack in the lower layer other than the surface layer, not only the ink absorption rate of the lower layer is increased, but also the ink absorption capacity is greatly increased, and the ink is hardly absorbed by the support. For this reason, even after recording, the recording medium is not wavy, and a printed matter of better quality can be obtained. Also, if the recording layer in the lower layer has cracks, the ink absorption rate of the surface layer increases,
Printing quality is good and printing can be performed without bleeding. The most desirable embodiment of the present invention is a recording medium having a crack in the lower layer and no crack in the surface layer. If there is a crack in the lower layer, an ink absorption rate can be obtained even if there is no crack in the surface layer, a dye having a relatively high molecular weight in the ink is fixed to the surface layer, and water and a solvent having a relatively low molecular weight are absorbed in the lower layer. Therefore, even if the amount of coating is small, not only can a recording medium having a high ink absorption speed and a high ink absorption capacity be obtained,
Since there are no cracks in the surface layer, dots having high roundness can be obtained, and a high-definition image can be obtained.

In general, it has been almost impossible to provide a crack in the lower layer and to provide no or less cracks in the upper layer. However, as a result of intensive studies in the present invention, the lower layer was used as a support. It was found that, after coating and forming a crack, the crack was once filled with a solvent or water or the like, then the upper layer was coated and dried as it was to obtain a recording medium having a crack in the lower layer. Further, a surface layer (of course, another recording layer may be further applied on the surface layer in order to obtain an ink absorption capacity) is applied and dried on the molding surface, and the lower layer is applied to the support to form cracks. Then, by laminating the molded surface with the surface layer and peeling off the molded surface, it is possible to obtain a high gloss ink jet recording medium having a photographic tone.

When at least one recording layer of the present invention, preferably a surface layer, contains secondary ultrafine particles having an average particle diameter of 10 to 300 nm formed by aggregation of primary particles having a particle diameter of 3 to 40 nm, higher gloss can be obtained. Thus, an ink jet recording body having excellent printing density can be obtained. When a cationic compound is blended in the upper recording layer, the anionic dye can be more easily fixed, and the resulting printed matter has significantly improved water resistance and long-term storage stability.

The present invention includes, but is not limited to, the following aspects. An outline of the present invention is shown in FIG. Of course, the configuration is not limited to the configuration shown in the schematic diagram. [1] In an ink jet recording medium having two or more recording layers on a support, at least one of the lower layers other than the surface layer on the recording side (the layer farthest from the support) has a crack, and An ink jet recording material, wherein ink jet printing is performed on a layer having a crack, and when the formed print dot having a diameter of 50 μm is observed at a magnification of 150 times with an optical microscope, cracks are observed in 30% or more of the print dot. [2] The ink jet recording material according to [1], wherein the cracks are always present within a square of 200 μm. [3] The ink jet recording material according to [1] or [2], wherein the ink jet recording medium has cracks in the surface layer, and the presence rate (%) of the cracks in the surface layer is smaller than that of the lower layer having the cracks. . [4] The ink jet recording material according to [1] or [2], wherein the surface layer has no crack.

[5] The at least one recording layer has an average particle size of 10 to 10 which is formed by aggregating primary particles having an average particle size of 3 to 40 nm.
The inkjet recording material according to any one of [1] to [4], comprising secondary ultrafine particles of 300 nm. [6] The ink jet recording medium according to [5], wherein each layer contains secondary ultrafine particles having an average particle diameter of 10 to 300 nm formed by aggregation of primary particles having an average particle diameter of 3 to 40 nm. [7] The ink jet recording material according to [5] or [6], wherein the secondary ultrafine particles are a silica sol, an alumina silicate sol, an alumina sol (including pseudo-boehmite sol), and a calcium carbonate sol.

[8] The ink-jet recording medium according to any one of the above, wherein at least the surface layer contains a cationic compound. [9] The ink jet recording material according to [8], wherein the cationic compound is a cationic resin. [10] The ink jet recording medium according to any one of the above, wherein the pore volume of the surface layer is in the range of 0.2 to 3.0 cc / g. [11] Inkjet printing is performed on the layer having the cracks in the lower layer, and a print dot having a diameter of 50 μm is observed with an optical microscope at a magnification of 150 times, and cracks are observed in 60% or more of the print dots. The inkjet recording material according to any one of [1] to [10].

[12] An ink jet recording medium having two or more recording layers on a support, and at least one of the lower layers other than the surface layer (the layer farthest from the support) on the recording side has cracks. A method of manufacturing an ink jet recording medium in which at least the surface layer is coated and formed on a molding surface, transferred to a support (or another recording layer if the support has another recording layer in advance), and separated from the molding surface. Production method. [13] The ink jet recording medium according to [12], wherein the recording layer applied to the molding surface is transferred to a support via an intermediate layer. [14] The ink jet recording material according to [13], wherein the intermediate layer is a pressure-sensitive adhesive, an adhesive or another recording layer. [15] A method for producing an ink jet recording medium having two or more recording layers on a support, wherein at least one of the lower layers other than the surface layer on the recording side (the layer farthest from the support) has a crack. There is provided a method for producing an ink jet recording medium in which a lower layer is applied and dried on a support, water or a solvent is applied thereon, and a surface layer is applied and then dried.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to an ink jet recording medium having two or more recording layers, wherein at least one layer has a crack in a lower layer other than the surface layer (the layer farthest from the support). A recording medium is provided. The ink jet recording medium of the present invention has high ink absorption speed, high ink absorption capacity, high print density, and high print quality. The crack in the present invention is defined as follows. Using an ink-jet recording medium, arbitrarily select 10 places from the recording medium and use a 720 dpi × 720 dpi ink-jet printer (for example, PM-700C manufactured by EPSON) to select 1 place per 1 mm ² at these 10 places.
00 to 200 dots (the size of one dot is approximately 5
0μ) is evenly hit, and observed under an optical microscope at a magnification of 100 to 200 times (for example, 150 times). If a crack is observed in 30% or more of the dots, it is determined that the dot has a crack.
Those in which no crack is observed in the above dots are defined as having no crack. Preferably at least 60%, more preferably 70%
% Or more of the dots are observed to be cracked. When observing a crack in the lower layer, all layers above the lower layer can be scraped off and observed by the above-described method, or the surface between the cracked layers can be observed. When the print dot is larger than 50 μm, it can be observed assuming a concentric circle having a diameter of 50 μm. The crack referred to in the present invention is of an irregular shape, and does not form a crack by mechanical means after the formation of the coating layer, but occurs naturally in a drying process. When the capacity of the crack is small, the effect of improving the ink absorption capacity by the crack is small. On the other hand, when the capacity is too large, the crack becomes too large and the surface of the recording layer may be rough. The width of the crack is not particularly limited, but is, for example, in a range of 0.5 to 10 μm. If the width of the crack is too large, the surface layer is likely to sink, and there is a possibility that a surface layer having extremely excellent gloss may not be obtained. Although the length is not particularly limited, it is, for example, 5 to 200 μm, as measured from the branched portion of the crack.
It is. When the cracked layer is measured by a mercury intrusion method, its capacity is, for example, 0.5 to 10 ml / g.

In the present invention, the support is not particularly limited, and may be transparent or opaque. For example, plastic films such as cellophane, polyethylene, polypropylene, soft polyvinyl chloride, hard polyvinyl chloride, polyester, etc., high quality paper, art paper, coated paper, cast coated paper, foil paper, kraft paper, polyethylene laminated paper, impregnated Paper such as paper, vapor-deposited paper, and water-soluble paper, metal foil, and synthetic paper are used as appropriate.

Next, the recording layer of the present invention will be described in detail. The recording layer is composed of two or more layers, and each layer desirably contains a pigment and an adhesive (binder). Examples of pigments include silica, alumina silicate, kaolin, clay, calcined clay, zinc oxide, tin oxide, magnesium sulfate, aluminum oxide, aluminum hydroxide, pseudoboehmite, calcium carbonate, satin white,
Aluminum silicate, smectite, magnesium silicate,
Various pigments known and used in the general coated paper field, such as magnesium carbonate, magnesium oxide, diatomaceous earth, styrene plastic pigment, urea resin plastic pigment, and benzoguanamine plastic pigment, are appropriately used. In order to obtain high printing density and high gloss, it is preferable to select secondary particles having an average particle diameter of 10 to 300 nm, which are obtained by aggregating primary particles of 3 to 40 nm, for the various pigments. More preferably, secondary particles having an average particle diameter of 20 to 200 nm formed by aggregation of primary particles of 5 to 30 nm are selected.

In order to obtain secondary particles (dispersion) having an average particle diameter of 10 to 300 nm, it is possible to obtain various commercially available pigments (several microns) by applying a strong force by mechanical means. That is, breaking dow
It is obtained by the n-method (method of subdividing a bulk raw material).
As mechanical means, an ultrasonic homogenizer, a pressure homogenizer, a nanomizer, a high-speed rotation mill, a roller mill, a container driving medium mill, a medium stirring mill, a jet mill,
Mechanical methods, such as a grinder and a sand grinder, may be used. The resulting ultrafine particles may be colloidal particles or slurries. In order to better obtain the effects (print quality, high-definition image) of the present invention, silica, alumina silicate, alumina (including pseudo-boehmite), and calcium carbonate are preferable as the pigment. All the average particle diameters referred to in the present invention are particle diameters (Martin diameters) observed with an electron microscope (SEM and TEM) (see “Particle Handbook”, Asakura Shoten, p. 52).

The adhesive (binder) used in each layer of the present invention includes a water-soluble resin (for example, polyvinyl alcohol (hereinafter also referred to as PVA), casein, soybean protein, synthetic proteins, starch, cellulose derivatives such as carboxymethylcellulose and methylcellulose). ), Styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer conjugated diene polymer latex, acrylic polymer latex, vinyl copolymer latex such as styrene-vinyl acetate copolymer, etc. Known adhesives (binders) used for paper are used alone or in combination. In order to increase the adhesiveness between the recording layer and the support or between the recording layers, a water-soluble resin is preferably used. In particular, when PVA having a degree of polymerization of 2,000 or more is used, an ink jet recording medium having good adhesion between the recording layer and the support or between the recording layers, high ink absorption speed, high ink absorption capacity, high printing density, and water resistance can be obtained. .

In each layer, the weight ratio of the solid content of the pigment and the adhesive (binder) is adjusted in the range of 100/2 to 100/200, preferably 100/5 to 100/100. When the amount of the adhesive (binder) added is large, the pores between the particles become small, and it is difficult to obtain an ink absorption rate, and it is also difficult to form a crack. On the other hand, adhesive (binder)
If the content is too small, the adhesive strength between the recording layer and the support or between the recording layers is too weak, and there is a possibility that a phenomenon of powder falling when the recording medium is used may occur. In order to cause cracks in the coating layer, a reduction in the amount of an adhesive (binder) and an increase in drying temperature can be mentioned. The occurrence of cracks depends on the particle size and type of the pigment, the type of adhesive, and the amount of coating. Here, a specific description will be given using an example. For example, a silica slurry of secondary particles having a particle size of 70 nm composed of primary particles having a particle size of 15 nm is used as a pigment, and polyvinyl alcohol having a polymerization degree of 2400 and a saponification degree of 98% or more (trade name: Kuraray Co., Ltd., trade name: When PVA-124) is used, when the pigment / polyvinyl alcohol is 100/50 and the coating amount is 20 g / m ² , cracks occur at a drying temperature of 120 ° C. 100/60
Then the cracks disappear. On the other hand, even if the pigment / polyvinyl alcohol ratio is 100/50, cracking does not occur when the drying temperature is 80 ° C. Next, for example, as a pigment, a particle diameter of 45 nm
When colloidal silica (manufactured by Nissan Chemical Industries, trade name: ST-XL) which is the primary particle of the above is used and the same polyvinyl alcohol as the binder is used, pigment / binder = 100/10, coating amount 20 g / m ² , drying temperature 12
Cracks occur at 0 ° C., but at 100/20, cracks disappear.

A cationic resin can be added to the recording layer for the purpose of improving ink fixability. It is preferable to add a cationic resin in the recording layer of the invention, particularly in the upper layer. Examples of the cationic resin to be added include polyalkylene polyamines such as polyethylene amine and polypropylene polyamine, or derivatives thereof, acrylic resins having a tertiary amino group or a quaternary ammonium group, and various commercially available known resins such as diacrylamine. A publicly available cationic resin may be used. The amount of the cationic resin added is adjusted in the range of 1 to 30 parts by weight, more preferably 5 to 20 parts by weight, based on 100 parts by weight of the pigment. In addition, dispersants, thickeners, defoamers used in general coated paper production,
Various auxiliaries such as a coloring agent, an antistatic agent, and a preservative are appropriately added.

The recording layer may be composed of two layers or three or more layers. The coating amount of each layer is not particularly limited, but preferably the coating amount of the surface layer is 1 to 50 g /
m ² , more preferably ² to ²⁰ g / m ² .
The preferable total coating amount of the recording layer other than the surface layer is 1 to 60 g / m.
² , more preferably ² to 40 g / m ² . Since the recording layer having a crack has a large ink absorption capacity, it is required to completely absorb the ink in the high print density portion with 1 to 40 g / ink.
Preferably, it is adjusted to m ² . More preferably, 2-3
Adjust to 0 g / m ² . If the coating amount is small, it is difficult to obtain a uniform coating film, while if the coating amount is large, the effect is saturated and is meaningless.

In a preferred embodiment of the present invention, the surface layer (of course,
After another coating layer may be formed on the surface, a recording layer may be formed on the molding surface, and then another recording layer is coated on the support to cause cracks, and the substrate is bonded to the surface layer (of course, the support (A crack may be formed after the other recording layer is coated and bonded to the surface layer.) By peeling off the molding surface, a higher gloss can be obtained.

Materials used for the molding surface include plastic films having high surface smoothness, such as cellophane, polyethylene, polypropylene, soft polyvinyl chloride, hard polyvinyl chloride, polyester, etc., polyethylene laminated paper, glassine paper, impregnation. Papers such as paper and vapor-deposited paper, flexible sheets such as metal foil and synthetic paper, and drums and plates having a highly smooth surface such as inorganic glass, metal and plastic are appropriately used. In particular, from the viewpoint of the manufacturing process and the suitability for peeling the molded surface and the recording layer, etc., a polymer film (polyethylene, polypropylene, polyester, etc.)
Metal drums having a high smooth surface are preferred.

The molded surface is preferably smooth for the purpose of imparting gloss, and the surface roughness of the molded surface (JIS B-060)
In 1), Ra is preferably 0.5 μm or less, more preferably Ra is 0.05 μm or less. The surface roughness can be controlled to give a texture such as semi-gloss tone or matte tone.

The molding surface may be left untreated. However, in order to control the adhesion between the recording surface and the recording layer to be smaller than the adhesion between the recording layer and the support (or another recording layer), the coating on the molding surface is controlled. It is possible to apply a compound having releasability, such as silicone or fluororesin, on the surface to be used. The bonding method is not particularly limited as long as the recording layer coated on the molding surface and the support (or another recording layer) can be bonded, but the recording layer is directly pressed and bonded to the recording layer on the support. Examples of the method include a method in which a recording layer is provided on a support, bonded to a recording layer coated on a molding surface in a wet state, dried, and then peeled from the molding surface.

Examples of the coater for coating the recording layer and the intermediate layer include various known coaters such as a die coater, a blade coater, an air knife coater, a roll coater, a bar coater, a gravure coater, a rod blade coater, a lip coater, and a curtain coater. Device.

In the present invention, it is necessary that at least one layer in the lower layer other than the surface layer has a crack. In general, it has been difficult to provide a lower layer with cracks and an upper layer without cracks or with fewer layers than the lower layer. If the lower layer has cracks, when the upper layer is provided, the pigment or binder in the upper layer sinks into the cracks, and the lower layer is no longer cracked, so that a recording layer having a high ink absorption capacity cannot be obtained. In the present invention, as a result of diligent studies, first, the lower layer is applied to the support, cracks are generated, and the cracks are temporarily removed with a solvent (such as alcohol) so that the pigment or binder in the upper layer does not sink into the cracks. Alternatively, after filling with water or the like, the upper layer is applied and dried as it is to obtain a recording medium having a crack in the lower layer. Further, a surface layer (of course, another recording layer may be further applied on the surface layer in order to obtain an ink absorption capacity) is applied and dried on the molding surface, and the lower layer is applied to the support to form cracks. Then, by laminating the molded surface with the surface layer and peeling off the molded surface, it is possible to obtain a high gloss ink jet recording medium having a photographic tone. Lamination is performed under pressure (5-150
Kg / cm) and, if necessary, heat (30 to 100 ° C.), but more preferably, steam is applied to the upper layer and / or the lower layer so that the moisture becomes 50 to 350% of the absolute dry weight of the recording layer. Alternatively, it can be realized by applying water and pressing with a calendar or the like. Of course, the recording layer (lower layer) is applied to the support, and is bonded in a wet state to the surface layer (preliminarily applied and dried on the molding surface), and then a crack is generated in the lower layer in the drying process, and the molding surface is peeled off. However, it is possible to obtain a high gloss ink jet recording medium having a photographic tone. The crack can be realized by reducing the amount of the adhesive (binder) and increasing the drying temperature as described above.

In the present invention, since cracks are formed in the lower layer other than the surface layer, if the dye penetrates to the lower layer, bleeding of the print may occur. desirable. If there is a crack in the lower layer, an ink absorption rate can be obtained even if there is no crack in the surface layer, the dye in the ink is fixed to the surface layer, and only the water and the solvent in the ink are absorbed in the lower layer. If there are few cracks in the surface layer, dots having high roundness can be obtained, and a high-definition image can be obtained. To stop the dye in the ink on the surface layer, the pore volume of the surface layer should be 0.2
It is preferably in the range of ~ 3.0 cc / g. A more preferred range is a pore volume of 0.5 to 2.5 cc / g. The pore volume of the present invention was measured with a pore sizer 9320 (manufactured by Shimadzu Corporation) by a mercury intrusion method after a recording layer was provided on a film and the recording layer was peeled off with a cutter or the like in order to avoid the influence of the support. In particular, the pore volume in a region having a pore radius of 6 μm or less is preferably within the above range.

The ink used in the ink jet recording method of the present invention comprises, as essential components, a dye for forming an image and a liquid medium for dissolving or dispersing the dye, and if necessary, various dispersants and an interface. It is adjusted by adding an activator, a viscosity adjuster, a specific resistance adjuster, a pH adjuster, a fungicide, a dissolution or dispersion stabilizer of the recording agent, and the like.

Examples of the recording agent used in the ink include direct dyes, acid dyes, basic dyes, reactive dyes, edible dyes, disperse dyes, oil dyes, and various pigments. Can be used without. The content of such a dye is determined depending on the type of the liquid medium component, the characteristics required for the ink, and the like, but in the case of the ink of the present invention, the composition as in the conventional ink, that is, There is no particular problem in use at a ratio of about 0.1 to 20% by weight.

As the solvent of the ink used in the present invention, water and various water-soluble organic solvents such as methyl alcohol, ethyl alcohol, n-propyl alcohol,
C1-C4 alkyl alcohols such as isopropyl alcohol, n-butyl alcohol and isobutyl alcohol; ketone or ketone alcohols such as acetone and diacetone alcohol; polyethylene glycol, polyalkylene glycols such as polypropylene glycol, ethylene glycol; , Alkylene groups such as propylene glycol, butylene glycol, triethylene glycol, thiodiglycol, hexylene glycol, diethylene glycol having 2 to 6 alkylene glycols, amides such as dimethylformamide, ethers such as tetrahydrofuran, glycerin, Multivalent alcohols such as ethylene glycol methyl ether, diethylene glycol methyl (ethyl) ether, and triethylene glycol monomethyl ether Such as a lower alkyl ether of Le and the like.

[0031]

The present invention will be described in more detail with reference to the following Examples, but it should be understood that the present invention is by no means restricted thereto.
Unless otherwise specified, parts and% in the examples are solid contents excluding water, and represent parts by weight and% by weight, respectively.

[Crack] Using an ink-jet recording medium, arbitrarily select 10 places from the recording medium, and obtain 720 dpi × 72
A 1-dpi inkjet printer (manufactured by EPSON, trade name: PM-700C) is used to place 1 mm
100 dots per ² are evenly struck (size of one dot is about 50μm), observed under magnification of 150 times with an optical microscope, and if cracks are observed in more than 60% of the dots, there is a crack It is defined that no crack is observed in 60% or more of the dots. Hereinafter, for example, when a crack is recognized in 50% of the dots in the text, it is expressed as a crack 50%. In the following, the primary particle diameter does not change even after the pulverization treatment.

[Silica sol A] Synthetic amorphous silica having an average particle size of 3 μm (manufactured by Nippon Silica Industry Co., Ltd., trade name: Nipsi)
1, HD-2, primary particle diameter: 11 nm), and then pulverized and dispersed by a sand grinder, and further pulverized and dispersed by a pressure homogenizer, and pulverized by a sand grinder and a pressure homogenizer until the average aggregated particle diameter becomes 60 nm. The dispersing operation was repeated to prepare a 7% dispersion. [Silica Sol B] Synthetic amorphous silica having an average particle size of 3 μm (manufactured by Nippon Silica Industry Co., Ltd., trade name: Nipsil, LP, 1
(The following particle diameter: 16 nm), pulverized and dispersed by a sand grinder, further pulverized and dispersed by a pressure homogenizer, and repeated the pulverizing and dispersing operation of the sand grinder and the pressure homogenizer until the average particle diameter became 100 nm. A dispersion was made as a trial. [Silica Sol C] Synthetic amorphous silica having an average particle size of 1.5 μm (manufactured by Nippon Silica Industry Co., Ltd., trade name: Nipsil, E-1)
(011, primary particle diameter: 24 nm), pulverized and dispersed by a sand grinder, further pulverized and dispersed by a pressure homogenizer, and repeated the pulverization and dispersion operation of the sand grinder and the pressure homogenizer until the average particle diameter became 150 nm. A 12% dispersion was prototyped.

Example 1 To 100 parts of silica sol C was added polyvinyl alcohol (Cl
Re: product name: PVA-135H, degree of polymerization: 350
0, degree of saponification: 99% or more) 10% water mixed with 35 parts
Using solution, dry coating amount is 20g / m^TwoSo that
Commercially coated paper (manufactured by Oji Paper Co., Ltd., trade name: OK coated, 12
7.9 g / m^Two) Laminated (extreme)
Polyethylene on coated paper surface by rouge lamination method
25μm laminated, hereinafter simply laminated
Coated paper) and dried at 120 ° C
did. The cracks in the lower layer thus obtained were 80%. Continued
Water coating (20 g / m2) on the coating layer.^Two), Then
PVA (PVA-135H) 3 in 100 parts of silica sol A
Using a 7% aqueous solution mixed with 0 parts, the coating amount is 8 g / m ^Two
Coated on the coating layer described above, dried at 50 ° C.
The ink jet recording medium of the invention was manufactured. Surface cracks
30%. The pore volume of the surface layer is 0.9 ml / g.
Was.

Example 2 A diallyl dimethyl ammonium chloride-acrylamide copolymer (trade name: PAS-J-81, manufactured by Nitto Boseki Co., Ltd.) was used as a cationic resin in 100 parts of silica sol A15.
Was added, and the mixture was pulverized and dispersed again with a pressure homogenizer so that the average agglomerated particle diameter became 100 nm, and 20 parts of polyvinyl alcohol (trade name: PVA-135H, manufactured by Kuraray Co., Ltd.) was added to the obtained silica sol containing the cationic resin. And
An aqueous solution having a concentration of 8% was prepared. After applying water (20 g / m ² ) on the coating layer containing silica sol C on the same support as in Example 1 in the same manner, using the above surface coating solution, the coating amount was 8 g / m ^2. Coated, dried at 50 ° C,
An ink jet recording medium of the present invention was manufactured. The crack in the surface layer was 30%. The pore volume of the surface layer is 0.83 ml / g
Met.

Example 3 The surface layer coating solution shown in Example 2, ie, diallyldimethylamine
Containing ammonium chloride-acrylamide copolymer
Ricasol A contains polyvinyl alcohol (Kuraray, product
Name: PVA-135H) 20 parts was added and the coating solution was
PET film used as a molding surface (Toray Industries, Inc.)
Product name: Lumirror T, 50 μm, surface roughness Ra =
0.02 μm) with a dry coating amount of 8 g / m^TwoSo that
Coated and dried at 40 ° C. Cracks were less than 10%.
100 parts of silica sol C is added to polyvinyl alcohol
(Trade name: PVA-135H), 30 parts by weight
Using a 10% aqueous solution, the dry coating amount is 20 g / m ^TwoBecomes
Like general high-quality paper (rice tsubo: 157 g / m^Two), 1
Dried at 20 ° C. (cracks were 90%). continue,
Moisture in the cationic resin-containing layer provided on the PET film
Application (5 g / m^Two), After the calendar temperature reaches 75
Under the condition of 20 ° C. and a linear pressure of 20 kg / cm, the above two coating layers were
After lamination, the PET film was peeled off, and
An ink jet recording medium was manufactured. The pore volume of the surface layer is 0.
It was 76 ml / g.

Example 4 To the surface coating solution shown in Example 2, ie, silica sol A containing diallyldimethylammonium chloride-acrylamide copolymer, 20 parts of polyvinyl alcohol (trade name: PVA-135H, manufactured by Kuraray Co., Ltd.) was added. A coating amount of 8 g / PET film (manufactured by Toray Industries, trade name: Lumirror T, 50 μm) using the coating liquid as a molding surface was used.
m ² and dried at 40 ° C. 10% crack
It was below. Subsequently, a silica sol B is placed on this coating layer.
100 parts of a 10% aqueous solution obtained by mixing 35 parts of polyvinyl alcohol (manufactured by Kuraray Co., Ltd., trade name: PVA-135H) with a coating amount of 10 g / m ² , 80
Dried at ° C. Cracks were 20%. Silica sol C1
00 parts of polyvinyl alcohol (manufactured by Kuraray Co., Ltd., trade name: PVA-135H) using 10% aqueous solution of a mixture of 25 parts of generally high quality paper as the coating amount becomes 10 g / m ² (basis weight: 157 g / m ² ), bonded to the above-mentioned coating layer, dried at 130 ° C., and peeled off the PET film to produce an ink jet recording body of the present invention. The cracks in the silica sol C layer were 95% (the cracks were observed by printing after shaving the upper layer). The pore volume of the surface layer is 0.76 m
1 / g.

Example 5 100 parts of silica sol C was added to polyvinyl alcohol (Cl
35 parts of PVA-135H (trade name, manufactured by Re Co., Ltd.) were mixed.
Using a 10% aqueous solution, the dry coating amount is 20 g / m ^TwoBecomes
And then dried at 100 ° C.
Cracks were 65%. Then, apply water on the coating layer
(15g / m^Two), And put 100 parts of silica sol A
25 parts of vinyl alcohol (PVA-135H) mixed
Using a 7% aqueous solution, a coating amount of 8 g / m^TwoSo that
Is coated on the coating layer, dried at 80 ° C.
A jet recording medium was manufactured. 80% cracks on the surface
Was.

Comparative Example 1 100 parts of silica sol B was mixed with polyvinyl alcohol (Cl
45 parts, manufactured by Re Co., Ltd., trade name: PVA-135H)
Using 10% aqueous solution, dry coating amount is 28 g / m ^TwoBecomes
And then dried at 100 ° C.
Cracks were less than 10%. Comparative Example 2 100 parts of silica sol C
(Trade name: PVA-135H), 40 parts were mixed.
Using a 10% aqueous solution, the dry coating amount is 20 g / m ^TwoBecomes
And then dried at 100 ° C. turtle
The crack was 20%. Then, apply water on the coating layer
(20 g / m^Two), And put 100 parts of silica sol A
Mix 30 parts of vinyl alcohol (PVA-135H)
Using a 7% aqueous solution, the dry coating amount is 8 g / m^TwoBecomes
On the coating layer, dried at 50 ° C.
A recording medium was manufactured. The crack in the surface layer was 30%.
The pore volume of the surface layer was 0.91 ml / g.

Comparative Example 3 A 100% silica sol was mixed with 40 parts of PVA (trade name: PVA-135H, manufactured by Kuraray Co., Ltd.), and a 10% aqueous solution was used. Laminate coating was performed so that the dry coating amount was 20 g / m ^2. The coated paper was coated and dried at 100 ° C. 20% crack
Met. Subsequently, water coating (15 g / m
² ), a 7% aqueous solution obtained by mixing polyvinyl alcohol (PVA-135H) 25 with 100 parts of silica sol A is applied on the coating layer so that the dry coating amount is 8 g / m ^2. It dried at ℃, and manufactured the inkjet recording body of the present invention. The crack in the surface layer was 80%.

Comparative Example 4 Commercially available glossy paper (trade name: GP-10, manufactured by CANON)
1) was used. The surface layer had cracks, and the cracks were 100%. [Evaluation method] The ink absorption speed, ink absorption capacity, glossiness, and the like of the ink jet recording material obtained in each of Examples and Comparative Examples were evaluated.
The print density and the like were evaluated by the following methods. For glossiness and print density, a commercially available inkjet printer (EP
It shows the glossiness and print density of a solid portion when recording was performed with SON Corporation, trademark: PM-700C. [Ink absorption speed] Single-color yellow, magenta, and cyan are overprinted so that the printed portion is solid black, and high quality paper is stuck on the print surface printed every 5 seconds immediately after printing, and the ink is applied to the high quality paper. Observe whether to transcribe. The time until no transfer occurs at all is measured. The measured number of seconds was evaluated in four steps (◎: 5 seconds or less, ：: 5 to 10 seconds,
Δ: 10 to 30 seconds, ×: 30 seconds or more).

[Ink Absorbing Capacity] An ink jet recording medium of the present invention of 10 cm × 10 cm square was attached to the center of A4 size PPC paper, and the ink ejection amount was 40 g / m ^2.
The black ink is solid-printed on the sheet of the present invention in such a manner that the paper is adhered to the printed surface printed every 10 seconds immediately after printing, and it is observed whether or not the ink is transferred to the high-quality paper. Measure the time until no transfer occurs, and
Graded (◎: less than 10 seconds, ：: 10 to 30 seconds,
Δ: 30 to 1 minute, ×: 1 minute or more).

[Glossiness of Printed Area (Glossiness)] The glossiness of the printed area was visually evaluated from a lateral angle with respect to each of black, yellow, cyan, and magenta printed areas, and evaluated in four steps as follows. ：: There is the same level of shine as a silver halide color photograph. ：: Inferior to color photograph, but with high shine. Δ: comparable to general commercial coated paper or art paper. X: There is no shininess at all.

[Print Density] The print density of the solid black portion was measured using a Macbeth reflection densitometer (Macbeth, RD-920). The numbers shown in the table are the average values of five measurements. [Moisture resistance storage] The printed product is stored in a constant temperature and humidity chamber at 40 ° C. and 90%, taken out after 48 hours, and observed for bleeding in the printed portion. A: No bleeding is observed at all. ：: bleeding is observed but at a practical level. Δ: The bleeding is large, and depending on the case (for example, at the time of summer high humidity), it may be difficult to use. X: A level at which bleeding is so severe that it cannot be used.

[Ripple] Each single color of yellow, cyan, and magenta is overprinted on the entire surface of the recording medium so as to be solid black, and the ripple of the recording medium after printing is evaluated. ：: Rippling is hardly observed. Δ: There is undulation, but practical level. X: A state in which undulation is severe and the quality is greatly reduced.

[0046]

[Table 1]

[0047]

As is clear from Table 1, the ink jet recording material obtained by the method of the present invention is an ink jet recording material having good ink absorbency and excellent glossiness, print density and the like.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a crack according to the present invention, and the left side of FIG. 1 shows an embodiment in which a recording layer has two layers and a lower layer has a crack. The right side of FIG. 1 shows an embodiment in which the recording layer is composed of three layers, and the lower one of the lower layers has a crack.

[Explanation of symbols]

1: recording layer (surface layer) 2: recording layer (lower layer having cracks) 3: support 4: recording layer (surface layer) 5: recording layer (layer located on the upper side of lower two layers) 6: recording Layer (lower layer of lower two layers, layer having cracks) 7: Support

Claims (9)

[Claims] Claims: 1. In an ink jet recording medium having two or more recording layers on a support, at least one of the lower layers other than the surface layer on which recording is performed (the layer farthest from the support) has cracks, In addition, when ink-jet printing is performed on the layer having the cracks, and when the formed print dots having a diameter of 50 μm are observed with an optical microscope at a magnification of 150 times, cracks are observed in 30% or more of the print dots. body. 2. The ink jet recording medium according to claim 1, wherein the surface layer has cracks, and the existence rate (%) of the surface layer cracks is smaller than that of the lower layer having the cracks. 3. The at least one recording layer has an average particle size of 3-4.
Average particle size of 10 to 300 formed by agglomeration of primary particles of 0 nm
3. The ink-jet recording material according to claim 1, which contains secondary ultrafine particles of nm. 4. An ink jet recording medium according to claim 3, wherein each layer contains secondary ultrafine particles having an average particle diameter of 10 to 300 nm formed by aggregation of primary particles having an average particle diameter of 3 to 40 nm. . 5. The ink jet recording medium according to claim 1, wherein at least the surface layer contains a cationic compound. 6. The pore volume of the surface layer is 0.2 to 3.0 cc / g.
The inkjet recording material according to any one of claims 1 to 5, wherein 7. An ink-jet printing is performed on the cracked layer in the lower layer, and a printed dot having a diameter of 50 μm is observed by an optical microscope at a magnification of 150 times, and a crack is observed in 60% or more of the printed dots. The ink-jet recording body according to any one of claims 1 to 6, wherein: 8. Production of an ink jet recording medium having two or more recording layers on a support, wherein at least one of the lower layers other than the surface layer on the recording side (the layer farthest from the support) is cracked. A method for producing an ink jet recording body in which at least the surface layer is coated and formed on a molding surface, transferred to a support (or another recording layer if the support has another recording layer in advance), and peeled off from the molding surface. Method. 9. Production of an ink jet recording medium having two or more recording layers on a support, wherein at least one of the lower layers other than the surface layer on the recording side (the layer farthest from the support) is cracked. A method for producing an ink jet recording medium comprising applying a lower layer on a support, drying the applied layer, applying water or a solvent thereon, further applying a surface layer, and then drying.