JP2000108503A - Ink jet recording paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording material which shows a superior surface gloss in the texture part and the recorded image part and also has the quality of a recorded image which is equal to or higher than that of a color photography-system photographic paper and further, visualizes a recorded image with a sophisticated feel. SOLUTION: This ink jet recording paper comprises a first porous ink receiving layer composed mainly of inorganic microparticles and a binder resin, formed on a support and a second ink receiving layer composed mainly of a resin, formed on the ink receiving layer. The loadings of the dry solid content of the first ink receiving layer are 5-50 g/m2 and the loadings of the dry solid content of the second ink receiving layer are 0.1-2.0 g/m2. Even after applying the second ink receiving layer, pores present in the first ink receiving layer are not necessarily blocked. In addition, the 60 deg. mirror surface glossiness of the second ink receiving layer surface is 60% or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an ink absorbing property,
An ink jet recording material that satisfies the basic characteristics as an ink jet recording material, such as excellent color developability and storability, is particularly high in surface gloss and has a very small reduction in gloss after recording, and has a high quality feel. The present invention relates to an ink jet recording paper capable of obtaining a high-quality recorded image having high quality.

[0002]

2. Description of the Related Art An ink jet recording system is a technology for recording images and characters by causing minute droplets of ink to fly based on various operating principles and attaching them to recording paper such as paper. A recording device using this technology operates at high speed with low noise, is easy to perform multi-color printing, and has no need for image forming processing using chemicals such as development and fixing. It is rapidly spreading in applications.

[0003] When the multicolor ink jet recording technique is used, it is also possible to obtain a high quality recorded image comparable to an image formed by a multicolor printing by a plate making method or an image formed by a color photographic method. For a small number of printing applications, printed matter can be produced at low cost. Therefore, recently, ink jet recording technology has been widely applied to the field of full-color image recording.

Conventionally, as a recording paper used in an ink jet recording system, a high quality paper or a coated paper used for ordinary printing or writing is used, and a recording device and an ink composition are examined from various aspects. It has been done. On the other hand, as seen in higher-speed, higher-definition, and full-color recording devices, the recent significant improvement in the performance of ink-jet recording devices has expanded the possibilities of recording technology using ink-jet recording methods, Is expanding year by year. Accordingly, higher quality-oriented recording suitability has been demanded of the ink jet recording paper, and higher quality characteristics than before have been required.

Conventionally, ink jet recording paper has
What has been required to have both the excellent image quality and the two requirements that the glossiness of the recorded image area does not decrease even after inkjet recording, but recently, in addition to this, it is equivalent to color photographic paper. However, there has been a demand for recording aptitude that can form a high-quality and excellent recorded image. In order to obtain a recorded image equivalent to such a color photographic printing paper, in addition to the requirements described above, the surface gloss itself of the ink jet recording paper must be higher gloss than before.
Furthermore, it is necessary that both the background portion and the recorded image portion have the same glossiness as the photographic printing paper surface. The required quality for these recorded images has recently been simply expressed as "photographic image quality" and has become widely known in general.

The quality required for the recording paper is that the density of each ink dot in the image recorded on the recording paper is high, the shape of the dots is close to a perfect circle, and the color tone is bright and vivid. Ink absorption is so fast that even if multiple ink dots overlap, ink does not flow or bleed on the surface of the recording paper, and the diffusion of ink dots in the horizontal direction relative to the recording paper surface is unnecessarily large. And the periphery of the dot is smooth and free of blur.

Further, a high-quality recorded image is obtained because the surface glossiness of the recording paper is high and the decrease in the glossiness of the image portion recorded on the recording paper is very small as compared with the background portion. Is an important factor for However, in general, the glossiness of a recording image portion of an ink jet recording sheet is lower than that of a background portion. This phenomenon is caused by the fact that the ink adhering to the surface of the recording paper is absorbed by the ink receiving layer and at the same time causes the resin and the filler contained in the ink receiving layer to re-dissolve and swell, so that the surface structure of the recording paper is destroyed. It is believed to occur because.

In order to solve these problems, some proposals have been made in the past as briefly described below.
First, as a method of obtaining excellent image quality, for example, ink jet recording paper (Japanese Patent Laid-Open No. 52-53012) in which a coating for surface processing is applied to low-size base paper, or urea-formalin resin powder is internally added. An ink jet recording paper (Japanese Patent Application Laid-Open No. 53-49113) in which a water-soluble resin is impregnated in a prepared sheet is disclosed. These plain paper type ink jet recording papers have a drawback that the ink absorption is quick, but the periphery of the dots is easily blurred and the dot density is low.

Japanese Patent Application Laid-Open No. 55-5830 discloses an ink jet recording paper provided with a coating layer having good ink absorbability on the surface of a support.
An example using silica powder as a filler in a coating layer is disclosed. In the case of these coated paper type ink jet recording papers, the dot diameter, dot shape, dot density and color tone reproduction of the attached ink are improved over the plain paper type ink jet recording paper.

[0010] On the other hand, aqueous inks using water-soluble dyes are currently the mainstream ink used for these ink jet recording papers. In this case, however, water is added to an image formed on the recording paper. In this case, the dye is dissolved again and oozes out from the recorded image area, so that the value of the recorded matter is significantly impaired. In addition, when the ink receiving layer contains a large amount of water-soluble resin, swelling or dissolution of the resin occurs upon contact with the ink, and the glossiness of the recording portion (the contact portion with the ink) is reduced to the background portion. There was a drawback that it was lower than that.

In order to improve these drawbacks, it has been proposed to include porous cationic hydrated aluminum oxide particles in the ink receiving layer to improve the water resistance of the recording paper (Japanese Patent Publication (Kokai) No. Hei 10-222). 3-24906). This focuses on the porosity of the cationic hydrated aluminum oxide. Since liquid substances such as ink and water enter the pores and are confined in the pores, the ink swells and dissolves the ink receiving layer. Is extremely unlikely to occur, and it is possible to suppress a decrease in glossiness of an image portion after recording.

According to this proposal, it has become possible to manufacture an ink jet recording sheet having both the excellent image quality and the requirement that the glossiness of a recorded image area does not decrease even after ink jet recording. However, this method still has a problem. In addition, it was not possible to obtain an ink jet recording paper having a sufficiently high surface gloss after recording.

Means for obtaining ink-jet recording paper having a sufficiently high surface gloss after recording include a method in which the ink-jet recording paper is pressed and passed between a heated steel roll and an elastic roll such as a calender, and the like.
Japanese Patent Application Laid-Open No. 6-79967 discloses a casting method in which an ink receiving layer is pressed and dried in a wet state on a heated mirror drum (for example, Japanese Patent Application Laid-Open No. 6-79967).

For example, hydrated aluminum oxide powder obtained by filtering, pressing, drying, pulverizing and classifying an alumina hydrogel slurry, and porous inorganic particles as secondary particles such as amorphous silica (Japanese Patent Publication No. 3-24906) Ink-jet recording paper coated directly with a binder together with a binder to form a coating film as an ink-receiving layer, a high-gloss surface can be obtained by the above-described method, but porous inorganic fine particles can be obtained. Thus, the pores formed by the ink are easily collapsed, so that the ink absorptivity is reduced and good image quality cannot be obtained.

[0015] Calendering, which is known as a general surface treatment technique, is a method in which a sheet-like substrate is pressure-bonded between a heated steel roll having a mirror surface and an elastic roll. A processing effect appears on the surface in contact with the roll. This technology is used in the final finishing process to improve the quality of the paper, the purpose of which is to make the uneven paper surface uniform and smoother and to give the paper surface good gloss. It is.

Therefore, when a calendering process is similarly performed for the final finishing of the ink jet recording paper, the coating applied to the surface layer of the sheet is smoothed by the high linear pressure applied between the rolls, and the gloss of the paper surface is increased. Can be imparted, but the gap between the rolls collapses due to the pressure between the rolls, which reduces the ink absorption layer, resulting in a decrease in the ink absorption capacity. Therefore, calendering has been generally unsuitable as the final finish of ink jet recording paper.

On the other hand, when the casting method is used, there are many restrictions on the viscosity and solid concentration of the coating material due to the properties of alumina hydrate particles such as alumina sol used for the ink receiving layer applied to the support. However, there is a disadvantage that it is difficult to increase the amount of coating and increase the thickness of the ink receiving layer. this is,
This is because, in the case of alumina hydrate particles such as alumina sol, when the solid content concentration in the coating material is increased, the viscosity is extremely increased, which causes a problem in suitability as a coating material. Therefore, it is not possible to form a thick ink receiving layer to sufficiently secure ink absorbability, and it is not possible to obtain good image quality.

The surface gloss of photographic paper is 60
The degree of specular gloss is as high as about 95%. If such surface gloss is imparted to the ink jet recording paper, it is possible to obtain a high-quality recording paper. However, in practice, it is difficult to give the recording paper a glossiness higher than that of the photographic printing paper in the measurement value of the glossiness. Then, the present inventors diligently studied the surface glossiness necessary for giving the appearance of high-grade appearance to the recording paper. It turned out that a sense of quality equal to or higher than that can be obtained.

[0019]

The inventors of the present invention have conducted intensive studies to provide a thick recording layer having high porosity, high gloss and excellent ink absorption on a support. Good results can be obtained by providing the first layer and the second recording layer so as to leave the pores of the first layer and to provide a gloss of 60% specular gloss of 60% or more. And found that the present invention was achieved. Accordingly, it is an object of the present invention to provide a high-quality recorded image having high surface gloss in both the background portion (unrecorded portion) and the recorded image portion, and having the same or higher recorded image quality as color photographic printing paper. An object of the present invention is to provide an ink jet recording material which can be obtained.

[0020]

SUMMARY OF THE INVENTION The above objects of the present invention are as follows.
Ink jet recording paper having a porous first ink receiving layer mainly composed of inorganic fine particles and a binder resin on a support, and a second ink receiving layer mainly composed of a resin on the ink receiving layer Wherein the coating amount of the dry solid content of the first ink receiving layer is 5 to 50 g / m ² , and the coating amount of the dry solid content of the second ink receiving layer is 0.1 to 2.0 g / m 2. ² , and the pores on the first ink receiving layer are not completely closed by the second ink receiving layer, and
Wherein the 60 ° specular glossiness of the surface of the ink receiving layer is 60% or more. In particular, the pore radius in the first ink receiving layer is 1 to 500n
m, and the average pore radius is 100 nm or less, and the second ink receiving layer has a porous structure that does not completely block the pores on the surface of the first ink receiving layer. Is preferred.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The support usable in the present invention may be appropriately selected from known supports having a strength that can be used as a support for ink-jet recording paper. And various films such as polypropylene, polyethylene terephthalate, etc.), a sheet obtained by laminating a resin film on the surface of paper, and a so-called laminated paper processed with a molten resin.

In the present invention, it is particularly preferable to use paper. For example, chemical pulp such as LBKP, NBKP, GP, PG
W, TMP, mechanical pulp such as CMP, waste paper pulp such as DIP etc. and known glue as main components, binder, sizing agent,
A base paper obtained by mixing a fixing agent, a paper strength enhancer, and the like, and obtained by various papermaking methods, and a size press treatment or a coating treatment (coated paper, art paper, cast paper, etc.) referred to in the field of papermaking on the above-mentioned base paper. ), Paper that has been subjected to calendar processing or the like can be used.

The inorganic fine particles used in the first ink receiving layer formed on the support have an average particle diameter of 10 to 500.
The coating liquid may be any one that forms a porous layer after coating and drying the coating liquid. For example, an oxide sol in which metal oxide fine particles are dispersed as colloid particles in a solvent (for example, silica sol, alumina sol, Zirconia sol, titania sol, etc.). In the present invention, in particular, when the inorganic fine particles are boehmite alumina hydrate particles having an average particle diameter of 10 to 500 nm and the solid content concentration is 15 to 30% by weight, the pH is 2%. It is preferred to use alumina sols of ~ 6.

The method for producing such an alumina sol is as follows.
There are methods such as adding an acid such as hydrochloric acid or acetic acid to a slurry containing alumina hydrate obtained by hydrolyzing an aluminum alkoxide such as aluminum propoxide, or peptizing using ultrasonic waves (for example, , JP 03-275510, JP 03-281384, JP 03-285814
No., JP-A-03-285815, JP-A-04-275917, JP-A-05
-24823, JP 05-24824, JP 05-32413, JP 06-64918, JP 06-64919, JP 07-29162
1, JP-A-08-295509 and JP-A-08-333115).

On the other hand, the pores between the inorganic fine particles formed in the first ink receiving layer are preferably small as long as the ink absorption is not impaired. For example, when inorganic fine particles having a pore radius as large as 3 μm are used as the first ink receiving layer, when the coating liquid for the second ink receiving layer is applied, the coating liquid Is quickly absorbed into the first ink receiving layer, so that the resin does not remain on the first ink receiving layer, so that not only the second ink receiving layer cannot be formed but also a glossy surface cannot be obtained.

Therefore, when the pore radius of the pores formed in the first ink receiving layer is reduced, when the second ink receiving layer is coated, the coating liquid for the second ink receiving layer is reduced. No.
The rate of absorption into the first ink receiving layer is suppressed, and more resin remains on the first ink receiving layer, so that if dried during that time, the second ink receiving layer having a glossy surface can be formed. . In the present invention, it is particularly preferable that the radius of the pores formed between the alumina hydrate particles is 1 to 500 nm, and that the average pore radius is substantially 100 nm or less.

As the binder resin used for the first ink receiving layer, a known resin which can be mixed with the above-mentioned inorganic fine particles and oxide sol and which can be coated and dried on a support to give a film. It can be appropriately selected from among them, but in order to further improve the ink absorbency, for example, a water-soluble resin such as polyvinyl alcohol, polyvinyl pyrrholine, water-soluble cellulose, and / or a conjugated material such as a styrene-butadiene copolymer. It is desirable to use an aqueous dispersion resin (polymer latex) such as a diene polymer, an acrylic polymer, or a vinyl polymer such as an ethylene-vinyl acetate copolymer.

Inorganic fine particles in the first ink receiving layer
The weight ratio of the dry solid content of the resin is preferably 97/3 to 70/30. The weight ratio of inorganic fine particles in the ink receiving layer is
If it exceeds 97, the film after coating and drying becomes brittle, and the ink receiving layer is liable to cause a powder drop phenomenon in which the ink receiving layer peels off from the support. On the other hand, the weight ratio of the inorganic fine particles in the ink receiving layer is 70%.
If it is smaller, the absorbability of the ink into the ink receiving layer is deteriorated. In the present invention, in particular, the weight ratio of inorganic fine particles / resin is preferably from 95/5 to 85/15.

The quality of ink absorptivity is based on the degree of blurring of the boundary of the image area and the beading phenomenon at the time of ink-jet recording. Boundary bleeding is a phenomenon in which it is difficult to distinguish boundaries between different colors adjacent to each other in a solid image portion recorded with ink of a single color or two or more colors without gaps. In addition, beading is a phenomenon in which not only a solid image portion but also a recorded image has a kind of stripe pattern or mottled shading.

In either case, since the ink droplets ejected from the ink nozzles of the ink jet recording apparatus are not uniformly absorbed by the recording paper, the unabsorbed ink droplets stay on the surface of the ink receiving layer. Happens to do. Boundary bleeding occurs when ink droplets continuously ejected on recording paper cannot be absorbed by the ink receiving layer and overflow from the receiving layer.
Furthermore, since the image bleeds into adjacent image portions, it is difficult to determine the boundaries between the images. On the other hand, the beading phenomenon does not mean that the ink absorbency is so low as to cause border bleeding, but the ink droplets continuously ejected are continuously recorded on the ink receiving layer before they are completely absorbed by the ink receiving layer. This is a phenomenon in which shading is formed in an image.

When the ink absorbency is poor, the boundary bleeding and the beading phenomenon occur remarkably. The coating liquid for the first ink receiving layer may contain a pigment dispersant, a coupling agent, a gelling agent, a thickening agent, a leveling agent, a defoaming agent or a defoaming agent, a surfactant, if necessary. Various additives such as a fluorescent whitening agent, a coloring dye, a coloring pigment, a fixing agent, an antioxidant, a UV absorber, and a waterproofing agent can also be blended.

The coating amount of the first ink receiving layer is an important factor that affects the suitability for ink jet recording. When alumina fine particles are used for the first ink receiving layer, water or alcohol, which is a solvent of the ink serving as a recording agent, can be absorbed by the alumina layer, and at the same time, a dye serving as a color forming component of the ink is used. Fixing (carrying) is also possible.

Further, since the first ink receiving layer described above has a very high transparency even when formed as a relatively thick film, the dye in the recording layer recorded by using the ink jet recording technique is more effective. It is possible to obtain a recorded image which looks sharp and has a high degree of coloring. In the present invention, the coating amount of the first ink receiving layer required to satisfy the ink jet recording suitability such as ink absorbency and color forming property is preferably 5 to 50 g / m ² , and particularly, 20-5
More preferably, the coating amount is 0 g / m ² .

The second ink receiving layer preferably has a porous structure in order to maintain the above-mentioned excellent characteristics of the first ink receiving layer without impairing the ink absorbency.
The preferred structure of the second ink receiving layer is, from the viewpoint of ink absorption, formed as a porous film on the first ink receiving layer instead of a continuous and uniform dried film, and formed on the surface of the first ink receiving layer. The structure is such that the formed pores are not completely closed. When the second ink receiving layer is a continuous and uniform dried film, the pores formed in the first ink receiving layer are closed, so that the ink absorbing property is significantly deteriorated. The porous structure of the second ink receiving layer can be confirmed with an electron microscope or the like.

In the present invention, it is necessary to balance the two objectives of forming an excellent recording image quality of an ink jet recording paper and forming a high-gloss and high-grade surface. Therefore, in order to satisfy excellent recorded image quality, high surface glossiness and high-grade feeling, the coating amount of the dry solid content of the second ink receiving layer is preferably 0.1 to 2.0 g / m ² , particularly , And a coating amount of 0.1 to 1.0 g / m ² .

When the coating amount of the dry solid content of the second ink receiving layer is less than 0.1 g / m ² , almost all of the applied liquid is in the first ink receiving layer before drying. Therefore, although the ink absorbability is good and excellent recording image quality can be obtained, the surface gloss of the ink jet recording paper cannot be increased. Also, the second
When the coating amount of the dry solid content of the ink receiving layer is larger than 2 g / m ² , a high surface gloss can be obtained, but at this thickness, it is difficult to form a film having a porous structure any more. Form a homogeneous continuous film. Therefore,
Since the second ink receiving layer closes the pores on the surface of the first ink receiving layer, a barrier property against the ink is generated, and the ink absorbing property of the first ink receiving layer is impaired. You can't get it.

The resin that can be used for the second ink receiving layer is
After the dry film is formed, any material having both high surface gloss and high ink absorbency (transmittance) may be used. Materials suitable for this purpose include, for example, polyvinyl alcohol and polyvinyl pyrrolidone, water-soluble cellulose, acrylic, polyacrylamide, polyester, cellulose acetate, acetal resin, melamine resin, urea resin, polyvinyl acetate,
Resins such as ethylene-vinyl acetate and polystyrene can be used.In particular, resins selected from polyvinyl alcohol, polyvinyl pyrrolidone, water-soluble cellulose, polyester, cellulose acetate, acetal resin, and colloidal silica composite styrene acrylic copolymer resin It is preferred to use. These resins can be used alone or as a mixture. By using the resin as described above, the second ink having a porous structure on the first ink receiving layer and having a glossy surface having a 60-degree specular glossiness of 60% or more.
Can be efficiently formed.

Preferred resins for the second ink receiving layer are resins having the following physical properties, respectively, but the relationship between the function developing mechanism and the physical properties is not yet clear. In the case of polyvinyl alcohol, a resin having a saponification degree of 5 to 45 mol% and an average polymerization degree of 100 to 2,500 is particularly preferable, and a resin having a heat melting temperature of 100 to 150 ° C. is particularly preferable. In the case of polyvinylpyrrolidone, it is particularly preferred to have an average molecular weight of 220,000 to 2.8 million. In the case of water-soluble cellulose, the viscosity of a 2% aqueous solution is 5%.
The resin is preferably 0 cps or more.

In the case of a polyester resin, a suspension in which fine particles of a polyester resin having an average molecular weight of 10,000 to 20,000 are dispersed in a mixed solvent of water and an organic solvent,
Alternatively, it is particularly preferable to use a water-soluble polyester resin. In the case of cellulose acetate, those having an average acetyl content of 10 to 60% by weight are preferred. In the case of an acetal resin, it is preferable to use a resin having an acetalization degree of 60 mol% or more, an acetyl group content of 3 mol% or less, and an average polymerization degree of 500 to 1,500.

In the case of the colloidal silica styrene-acrylic copolymer resin, a suspension in which fine particles made of a resin obtained by copolymerizing a monomer having an ethylenically unsaturated bond with styrene in the presence of colloidal silica is used is used. Is preferred. Examples of the monomer having an ethylenically unsaturated bond include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate,
-Hydroxyethyl acrylate, acrylates such as glycidyl acrylate, methyl methacrylate, ethyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate,
Methacrylic acid esters such as glycidyl methacrylate can be used. The composite ratio of styrene acrylic copolymer resin and colloidal silica is 10 /
It is preferably in the range of 90 to 90/10.

When a thermoplastic resin such as a polyester resin is used, if the glass transition temperature is too low,
Since there is a risk that the recording surface and the back surface may adhere to each other due to pressure when the ink-jet recording paper is stored in an overlapped state, it is preferable that the resin has a glass transition temperature higher than −10 ° C.
A particularly preferred resin composition for the second ink receiving layer is a blend of polyvinyl alcohol / polyester resin, and the composition ratio may be arbitrary, but is particularly preferably 60/40 by weight.
Preferably it is ~ 95/5.

In the second ink receiving layer, colloidal silica having various particle diameters, amorphous silica, silicon oxide, and the like may be used as needed, as long as the 60-degree specular gloss is not less than 60%.
Titanium oxide, aluminum oxide, zinc oxide, tin oxide, calcium carbonate, magnesium carbonate, magnesium sulfate,
Various inorganic fine particles such as aluminum silicate, magnesium silicate, kaolin, clay and zeolite, and resin powder such as plastic pigment can be appropriately added and used. Furthermore, as other additives, a plasticizer, a pigment dispersant, a thickener, a leveling agent, an antifoaming agent or a foam inhibitor, a surfactant, an optical brightener, a coloring dye, a coloring pigment,
Various additives such as a fixing agent, an antioxidant, a UV absorber, and a water-proofing agent can be blended.

The ink receiving layer of the ink jet recording paper of the present invention can be formed by a usual coating method using a blade coater, an air knife coater, a roll coater, a curtain coater, a die coater, a bar coater, a rod blade coater, a gravure coater, or the like. A method of drying and solidifying with hot air, infrared rays, or the like is used for drying the coating film.

As the ink which can be used for the ink jet recording paper of the present invention, an ink mainly composed of a dye necessary for forming a recorded image and a dispersion medium or a solvent necessary for dispersing the dye is used. . It is known that the dye in the ink can be a direct dye, an acid dye, a basic dye, a reactive dye, an edible dye, a disperse dye, an oil dye, various pigments, and the like. It can be appropriately selected from known color materials and used. In addition, water and water-soluble organic solvents such as alcohols and glycols are used for the liquid used as the dispersion medium or the solvent of the ink. In any case, a pigment in a usual range of 0.1 to 20% by weight is used. There is no particular problem with the blending amount.

[0045]

Since the ink jet recording paper of the present invention has a porous and thick ink receiving layer, it not only has a good ink absorbency but also has a large ink receiving ability, and in particular, has a high degree of excellent color image recording suitability. Color development.
In addition, since the surface gloss is excellent and the surface gloss of a recorded image portion after recording is small, a very high-quality image can be recorded by inkjet recording.

[0046]

The present invention will be described in more detail with reference to the following examples, but it should not be construed that the invention is limited thereto. In the examples, parts and% mean parts by weight and% by weight, respectively. The measurement of various physical properties was performed in the following manner. As a printing device, an inkjet printer (BJ, manufactured by Canon Inc.) is used as the printer 1.
C-420J), an ink-jet printer (PM700C) manufactured by Seiko Epson Corporation is used as the printer 2, and the inks are genuine inks designated by the respective manufacturers, cyan (C), magenta (M), yellow (Y), And black (BK).

As the coating amount of the ink receiving layer, JIS P81
By measuring the basis weight according to 24, the basis weight of the ink jet recording paper provided with the ink receiving layer and the basis weight of the support used for the recording paper were actually measured, and the difference between the two basis weights was calculated and used. Was. Glossiness conforms to JIS Z8741 for the ink receiving layer surface,
It was actually measured using a gloss meter GM-3D (manufactured by Murakami Color Research Laboratory) (incident angle of light 60 °). The color densities of the recorded images are cyan (C), magenta (M), yellow (Y), black (B
The reflection density of each solid portion of K) was actually measured using a colorimeter SPM 100 (manufactured by Gretag). The ink absorptivity was evaluated by boundary bleeding and beading in the recorded image area.

Regarding border bleeding, each of the ink jet printers was used to measure the size of a 30 mm × 30 mm square.
In a mixed color blue portion of cyan and magenta and a mixed color red portion of magenta and yellow recorded next to each other without a gap, the degree of bleeding at the boundary between the blue portion and the red portion was evaluated on a three-level basis based on visual sensory evaluation. went. The evaluation contents are as follows. High-quality recorded image without repelling, bleeding, or overflow of ink: ○ Repelling, bleeding, or spilling of ink is slightly observed, but recording quality is maintained: △ Repelling, bleeding, or overflowing of ink And the recording quality is impaired: × When the above evaluation criteria are followed, an evaluation of △ or more is required to obtain a high-quality recorded image.

Regarding the beading, cyan, magenta,
The presence or absence of color shading in a solid image portion of yellow, black, blue (mixed color of cyan and magenta), red (mixed color of magenta and yellow), and green (mixed color of cyan and yellow) is determined based on a visual sensory evaluation. 3
It was rated on a scale. The evaluation contents are as follows. High-quality recorded image without color shading unevenness in the recorded image area: ○ Slight color shading unevenness is recognized in the recorded image area, but the recording quality is maintained: Color shading is observed, and the recording quality is impaired: × In accordance with the above evaluation criteria, an evaluation of Δ or more is required to obtain a high-quality recorded image.

Embodiment 1 810 g of ion-exchanged water in the reaction vessel
And 676 g of isopropanol were charged, and the liquid temperature was heated to 75 ° C. The aluminum isopropoxide is then stirred
306 g was added, the liquid temperature was maintained at 75 to 80 ° C, and the stirring speed was 600
Hydrolysis was performed at rpm for 20 hours. Then, the mixture was heated while adding 400 g of ion-exchanged water to distill off isopropanol. While maintaining the temperature of the obtained slurry of alumina hydrate having a solid content of 10% by weight at 95 ° C., a 10% by weight aqueous solution of amidosulfuric acid was added as a deflocculant to 1 mol of aluminum atoms in boehmite. Amidosulfuric acid was added so that the amount became 11 mmol. The peptization is performed at a liquid temperature of 95 ° C. for 15 hours, and the liquid is further concentrated to obtain an alumina sol having a solid content of 21% by weight and a pH of 4.5 (disclosed in JP-A-08-333115). Manufacturing method).

As a support for the ink jet recording material, NPi foam (basis weight: 145 g / m ² , manufactured by Nippon Paper Industries Co., Ltd.) was used. As the coating liquid for forming the first ink receiving layer, with respect to 100 parts of the above-described alumina sol,
Polyvinyl alcohol (PVA-117, binder resin)
An aqueous dispersion having a concentration of 17%, comprising 6.5 parts of Kuraray Co., Ltd. and 523 parts of water, was prepared. Apply this coating solution at the Meyer bar
Coating was performed on the above support so that the coating amount of the dried solid content was 30 g / m ² , and the coating was dried in a hot air circulating dryer at 130 ° C. for 3 minutes to form a first ink receiving layer. .

As a coating liquid for forming the second ink receiving layer, 80 parts of polyvinyl alcohol having a saponification degree of 35 mol% and an average degree of polymerization of 300 and 20 parts of a polyester resin having a glass transition temperature of 20 ° C. ( Vylonal MD-1400,
A 2% aqueous dispersion of 2,450 parts of isopropyl alcohol and 2,450 parts of water was prepared. Using a Meyer bar, the coating amount of the coating liquid was 0.3 g on the already provided first ink receiving layer.
/ M ² and dried in a hot air circulating dryer at 120 ° C. for 1 minute to obtain an ink jet recording paper.

Embodiment 2 FIG. Performed up to the first ink receiving layer
Prepared in the same manner as in Example 1, and applied the second ink receiving layer
The liquid has a saponification degree of 35 mol% and an average polymerization degree of 300
Polyvinyl alcohol 80 parts and glass transition temperature of 67 ℃
20 parts of polyester resin (Vironal MD-120
0, Toyobo Co., Ltd.), isopropyl alcohol 2,450
A 2% aqueous dispersion consisting of 2 parts by volume and 2,450 parts of water
Made. This coating liquid is applied to the already provided first ink receiving layer.
On top, the coating amount of dry solids is 0.3 using a Meyer bar.
g / m ²Coating and drying with hot air circulation at 120 ° C
The ink was dried for 1 minute in a machine to obtain an ink jet recording paper.

Embodiment 3 FIG. The first ink receiving layer was prepared in the same manner as in Example 1, and as a coating liquid for the second ink receiving layer, 1 part of cellulose acetate (acetate flake, manufactured by Teijin Limited) and 99 parts of acetone were used. A solution having a concentration of 1% was prepared, and this coating solution was applied on the first ink receiving layer using a Meyer bar so that the coating amount of the dry solid was 0.2 g / m ^2. In a hot air circulating dryer at 120 ° C
After drying for an minute, an ink jet recording paper was obtained.

Embodiment 4 FIG. The first ink receiving layer was prepared in the same manner as in Example 1, and as a coating liquid for the second ink receiving layer, 10 parts of polyvinyl butyral (KS-1, manufactured by Sekisui Chemical Co., Ltd.), methanol A solution having a concentration of 2% consisting of 245 parts and 245 parts of water was prepared, and the coating liquid was subjected to first ink receiving using a Meyer bar so that the coating amount of the dry solid was 0.2 g / m ^2. The composition was coated on the layer and dried in a hot air circulating drier at 120 ° C. for 1 minute to obtain an ink jet recording sheet.

Embodiment 5 FIG. The first ink receiving layer was prepared in the same manner as in Example 1, and as a coating liquid for the second ink receiving layer, 85 parts of polyvinylpyrrolidone (K-90, IS
Company P) and 15 parts of melamine resin (Smileds Resin 61)
3, a Sumitomo Chemical Co., Ltd.) and 1,330 parts of water to prepare a coating solution having a concentration of 7% and using a Meyer bar, apply this coating solution to a dry solid content of 2 g / m2. The composition was coated on the first ink receiving layer so as to obtain No. ^2, and dried in a hot air circulating drier at 120 ° C. for 1 minute to obtain an ink jet recording sheet.

Embodiment 6 FIG. The components up to the first ink receiving layer were produced in exactly the same manner as in the case of 1 part by weight. Next, as a coating liquid for the second ink receiving layer, a colloidal silica composite styrene acrylic resin (Movinyl 8050, manufactured by Hoechst Gosei Co., Ltd.) was diluted with water to prepare a coating liquid having a concentration of 1%.
This coating liquid is applied on the first ink receiving layer using a Meyer bar so that the coating amount of the dry solid is 0.2 g / m ^2, and a hot air circulating dryer at 120 ° C. After drying for 1 minute in the ink, an ink jet recording paper was obtained.

Comparative Example 1 The coating liquid for forming the first ink-receiving layer used in Example 1 was applied on NPi foam (basis weight 145 g / m ² , manufactured by Nippon Paper Industries Co., Ltd.) which is a high-quality paper, Was adjusted to 20 g / m ² , pressed against a mirror-surface drum heated to about 100 ° C., and dried (casting method in the papermaking field) to obtain an ink jet recording paper.

Comparative Example 2 The coating liquid for forming the first ink receiving layer used in Example 1 was dried on a high quality paper NPi foam (basis weight 145 g / m ² , manufactured by Nippon Paper Industries Co., Ltd.) using a Meyer bar. Coating was performed so that the coating amount of the solid content was 30 g / m ² to obtain an ink jet recording paper.

Comparative Example 3 The first ink receiving layer was manufactured in the same manner as in Example 1, and a 3% concentration polyvinyl alcohol (B-2) was used as a coating liquid for the second ink receiving layer.
4. Shin-Etsu Chemical Co., Ltd.) aqueous solution was prepared. The obtained coating liquid is coated on the first ink receiving layer using a Meyer bar so that the coating amount of the dry solid content is 5 g / m ^2, and is dried by hot air circulation at 120 ° C. Drying was performed for 2 minutes in the machine to obtain an ink jet recording paper.

Comparative Example 4 The first ink receiving layer was prepared in the same manner as in Example 1, and as a coating liquid for the second ink receiving layer, 1 part of polyvinyl alcohol (B-04, manufactured by Shin-Etsu Chemical Co., Ltd.) and water A 0.1% aqueous solution consisting of 999 parts was prepared. The obtained coating liquid was applied on the first ink receiving layer using a Meyer bar such that the coating amount of the dry solid content was 0.02 g / m ^2, and a hot air circulation system at 120 ° C. The ink was dried in a dryer for 1 minute to obtain an ink jet recording paper.

Table 1 shows the evaluation results of the ink-jet papers obtained in Examples and Comparative Examples.

【table 1】

In each of Examples 1 to 5, ink-jet recording having good ink absorption and excellent recording image quality was performed. In addition, the surface glossiness of the background portion was as high as 60% or more, and the quality of the recorded image was high-quality, and high-quality recording was possible. On the contrary,
In Comparative Example 1, although the surface gloss of the background portion was slightly high, the ink absorbency was poor, and an excellent recorded image could not be obtained because of the low color density.

In Comparative Example 2, although the ink absorption was good, the surface glossiness of the background portion was low and the surface glossiness of the recording image portion was low, so that a high-quality recorded image could be obtained. Could not. Further, in Comparative Example 3, although the surface glossiness of the background portion was very high, it was possible to obtain a high-quality recorded image having very poor ink absorbability, probably because the second ink receiving layer had barrier properties. could not. In Comparative Example 4, although the ink absorption was excellent and the recorded image quality was excellent, the surface glossiness of the background portion and the recorded image portion was low, and a high-quality recorded image could not be obtained. The above results demonstrate the usefulness of the ink jet recording paper according to the present invention.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Fumiko Ito 1551 Higashimatsuyama, Higashimatsuyama-shi, Saitama Prefecture Nippon Paper Industries Co., Ltd. Term (reference) 2C056 FC06 2H086 BA16 BA21 BA32 BA35 BA36 BA41 BA44 BA45 4L055 AG17 AG18 AG46 AG57 AG63 AG64 AG71 AG82 AG97 AG99 AH02 AH37 AJ02 AJ04 BE09 EA11 EA14 EA16 EA18 EA30 EA32 EA33 FA12 GA09

Claims (6)

[Claims] 1. A porous first ink receiving layer mainly composed of inorganic fine particles and a binder resin on a support, and a second ink receiving layer mainly composed of a resin on the ink receiving layer. Wherein the coating amount of the dry solid content of the first ink receiving layer is 5 to 50 g / m ² , and the coating amount of the dry solid content of the second ink receiving layer is 0.1 g / m ^2. ~
2.0 g / m ² , the pores on the first ink receiving layer are not completely closed by the second ink receiving layer, and the 60 ° mirror surface of the surface of the second ink receiving layer Gloss 6
Ink-jet recording paper whose specialty is 0% or more. 2. An inorganic fine particle constituting the first ink receiving layer has an average particle diameter of 10 to 500 nm, and pores formed between the inorganic fine particles have a radius of 1 to 500 nm and an average fine particle diameter. 3. The ink jet recording paper according to claim 1, wherein the pore radius is 100 nm or less. 3. The ink jet recording paper according to claim 1, wherein the weight ratio of the inorganic fine particles to the binder resin in the first ink receiving layer is 97/3 to 70/30. 4. The method according to claim 1, wherein the second ink receiving layer contains at least one resin selected from the group consisting of polyvinyl alcohol, polyvinyl pyrrolidone, water-soluble cellulose, polyvinyl acetal, polyester, cellulose acetate, and colloidal silica composite styrene acrylic copolymer resin. The inkjet recording paper according to claim 1. 5. The ink jet recording paper according to claim 4, wherein the second ink receiving layer is made of polyvinyl alcohol having a saponification degree of 5 to 60 mol% and an average polymerization degree of 100 to 2,500. 6. The ink jet recording sheet according to claim 1, wherein the first ink receiving layer is a layer having high transparency.