JP2003285543A - Base for ink jet recording cast coated paper and ink jet recording cast coated paper using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a base for an ink jet recording cast coated paper with which the ink jet recording cast coated paper excellent in recording layer strength can be formed, and the ink jet recording cast coated paper using the same. <P>SOLUTION: The ink jet recording cast coated paper provided with a cast coated layer over an under layer on at least one side of a base paper in which the under layer contains synthetic amorphous silica (A) of an oil absorption of 200 ml/100 g or higher and ground calcium carbonate (B) having 95 wt.% or more of particles 2 μm or lower in particle size. The content of the synthetic amorphous silica and the ground calcium carbonate in weight ratio is, A:B=50:50-80:20. <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 a cast coated paper support for ink jet recording, and a cast coated paper for ink jet recording using the same.

[0002]

2. Description of the Related Art The ink jet recording method is a recording method in which minute droplets of ink are ejected by various methods to form images and characters on a recording material such as paper. Noise is low, full color printing and high speed recording are performed. It has features such as easy commercialization, and because the device is low-priced, it has achieved remarkable spread as various printers and plotters. In recent years, the size of ink droplets has been greatly reduced and the quality of ink has been greatly improved. As a result, the quality of images has been further improved, until images of levels comparable to those of silver salt photographs have been obtained, as represented by phototype ink inkjet printers. Therefore, the number of users who directly print a digital image taken by a digital camera with an inkjet printer is increasing.

The ink jet recording system ejects ink droplets from a nozzle toward a recording medium at a high speed. Particularly, in a high quality ink jet printer called a photo type, light color inks are used in addition to four colors of CMYK. A large amount of ink is ejected. Therefore, the recording medium is required to quickly absorb a large amount of ink. In consideration of ink absorption and ink bleeding, the ink jet recording medium is generally provided with an ink receiving layer composed of a porous pigment such as silica and a binder resin.

Further, with the spread of computers and digital cameras, images close to silver halide photographs have been demanded,
Inkjet recording paper is now required to have a photo-like glossy feel. As a method for imparting gloss to an ink jet recording paper, a super calendar method for smoothing the surface of the ink receiving layer to impart gloss, or a heated mirror surface of the ink receiving layer in a wet state or a plastic state There is a casting method in which the mirror surface is pressed onto the surface of the drum (cast drum), and the mirror surface is copied onto the surface of the recording paper at the same time as drying.

The following three methods are representative of the casting method. That is, a direct method in which the coating liquid applied to the support is pressure-bonded to a heated casting drum in a state where the coating liquid is not dried at all, or the coating liquid applied to the support is once dried or half-dried, and then re-dried. A rewet casting method in which the plastic material is returned to a plastic state by a wet liquid and then pressure-bonded to a heated casting drum, the coating liquid applied to the support is treated with a coagulating liquid, and has no fluidity. In this state, it is a solidification method in which it is pressed onto a heated casting drum.
All of these casting methods are common in that a high-gloss coating layer surface is obtained by copying a mirror-like drum surface.

In order to provide the ink jet recording paper with sufficient ink absorbency, it is general to increase the dry coating amount of the ink receiving layer. However, when the ink receiving layer having a large dry coating amount is provided by the casting method, it is difficult to set the coating amount large because the drying efficiency is poor. For this reason, it has been considered to make the ink receiving layer multi-layered and to supplement the insufficient ink absorbency of the cast layer alone with the under layer.

When the strength of the under layer is weak in the cast-coated paper for multi-layer ink jet recording, the strength of the recording layer of the final product after the casting process is weak, and troubles such as a large amount of paper dust occur at the time of cutter cutting. . Therefore, the under layer is required to have absorption capacity that compensates for insufficient ink absorption by the cast layer alone, and strength that does not cause a problem in handling of the final product (cast coated paper for inkjet recording).

[0008]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a cast coated paper support for ink jet recording capable of producing a cast coated paper for ink jet recording excellent in recording layer strength, and a cast coat for ink jet recording using the same. It is to provide paper.

[0009]

The above object was achieved by the present invention described below. That is, the present invention provides (1) a cast-coated paper support for inkjet recording, comprising at least one underlayer containing a pigment and a binder on at least one surface of a base paper, wherein the pigment of the underlayer is Is a synthetic amorphous silica (A) with an oil absorption of 200 ml / 100 g or more
And heavy calcium carbonate (B) containing 95% by weight or more of particles having a particle diameter of 2 μm or less, and the weight ratio of the synthetic amorphous silica to the heavy calcium carbonate in the under layer is A: B =
It is a support for cast coated paper for inkjet recording, which is 50:50 to 80:20. Further, the present invention comprises (2) the presence of a cationic dispersant on at least one surface of the base paper, which is synthetic amorphous silica having an oil absorption of 200 ml or more and heavy calcium carbonate containing 95% by weight or more of particles having a particle diameter of 2 μm or less. The support for cast-coated paper for inkjet recording according to (1), wherein an under layer is formed by applying a coating liquid containing a pigment dispersion liquid dispersed below. Further, the present invention uses (3) an aqueous coating liquid containing at least a pigment and a binder on the under layer of the inkjet recording cast coated paper support described in (1) or (2),
It is a cast-coated paper for inkjet recording having an ink receiving layer formed by a casting method.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The support for cast coated paper of the present invention comprises a base paper having an under layer provided on at least one surface thereof. The base paper is composed of wood pulp, fillers, auxiliaries and the like. Examples of materials that can be used as the wood pulp include known chemical pulp, mechanical pulp, deinking pulp, and the like. Further, these various pulps may be used alone or in combination as necessary. Known fillers and auxiliaries such as fillers and sizing agents, paper strength enhancers, retention aids, pH adjusters, and various dyes can be appropriately selected and added internally or externally to the base paper.

The under layer of the cast coated paper support of the present invention is provided on at least one surface of the base paper and contains a pigment and a binder. The pigment has an oil absorption of 200 ml
/ 100g or more of synthetic amorphous silica (A) and particle size 2μ
Heavy calcium carbonate (B) containing 95% by weight or more of particles of m or less is mixed and used at a weight ratio of A: B = 50: 50 to 80:20.

Calcium carbonate is roughly classified into two types,
One is a natural product (heavy calcium carbonate) made by physically crushing limestone as it is, and a precipitated product (light calcium carbonate) produced by chemically reacting various raw materials. Of these, heavy calcium carbonate is used in the present invention. Heavy calcium carbonate has a low oil absorption and can have a high surface strength with a small amount of binder, but it is difficult to secure the ink absorption capacity required as an under layer with heavy calcium carbonate alone. Therefore, in the present invention, the heavy calcium carbonate and the oil absorption amount are 200
ml / 100 g of synthetic amorphous silica is mixed and used.

The heavy calcium carbonate used in the present invention contains 95% by weight or more of particles having a particle diameter of 2 μm or less. The ratio of particles having a particle size of 2 μm or less is 9
If it is less than 5%, the surface area of the heavy calcium carbonate becomes small, and the ink absorption capacity of the under layer becomes poor. In order to obtain the ink absorption capacity, it is necessary to increase the proportion of synthetic amorphous silica, but in this case, the strength of the under layer becomes weak, which causes a problem.

If the average particle size is small, the strength of the under layer tends to decrease. Further, the fluidity of the liquid in which the heavy calcium carbonate is dispersed is deteriorated, and as a result, the coating suitability of the under layer coating liquid tends to be poor, and a problem tends to occur. Therefore, the heavy calcium carbonate of the present invention has an average particle size of 0.
The average particle size is preferably from 1 to 0.7 μm, and particularly preferably from 0.2 to 0.5 μm. The average particle size and particle size distribution are measured by a laser light diffraction / scattering method.

The synthetic amorphous silica used in the under layer used in the present invention has an oil absorption of 200 ml / 100 g.
Is preferable, and particularly 300 ml / 100 g or more is preferable. If the oil absorption is small, the ink absorption capacity of the under layer tends to be insufficient.

In the present invention, it is preferable to add a pigment dispersion liquid in which synthetic amorphous silica and ground calcium carbonate are dispersed to the coating liquid for the under layer. They may be dispersed individually and then mixed, or may be dispersed at the same time, or one pigment may be dispersed and then the other pigment may be added to the dispersion and dispersed. From the viewpoint of workability and control of the degree of dispersion, it is preferable that the synthetic amorphous silica and the ground calcium carbonate are separately dispersed and then mixed with the under layer coating liquid. A dispersant can be used when dispersing the synthetic amorphous silica or the ground calcium carbonate. In particular, it is preferable to use a cationic dispersant because a coating liquid having excellent coating suitability can be obtained even if a cationic auxiliary agent (ink fixing agent or the like) is added to the under layer coating liquid.

The mixing weight ratio of the synthetic amorphous silica (A) and the ground calcium carbonate (B) is A: B = 50: 50-80:
It is preferably 20 and more preferably 50:50 to 70:30. If the ratio of synthetic amorphous silica to ground calcium carbonate is less than 50:50, the ink absorption capacity of the under layer will be insufficient. On the contrary, 80:20
If it is larger, the ink absorption capacity of the under layer increases, but the strength of the under layer becomes weak. in this case,
In order to obtain the required strength of the under layer, more binder will be blended, but if a large amount of binder is used,
In general, the viscosity of the coating liquid increases and coating becomes difficult, which may cause uneven coating. Since the cast coat layer is preferably provided with a transparent layer in order to make the color of the ink vivid, uneven coating of the under layer causes unevenness of the final product (cast coated paper for inkjet recording), which is a problem.

The binder for the under layer is not particularly limited, and any resin can be used as long as it forms a film after coating and drying. However, since the surface strength of the under layer is required, Polyvinyl alcohol, which is a hydrophilic binder and has a very excellent effect on adhesion of materials having a polar surface such as cellulose fibers, and which can obtain strength of the under layer with a small amount, is preferably used. If necessary, starches such as oxidized starch and esterified starch, cellulose derivatives such as carboxymethyl cellulose and hydroxyethyl cellulose, proteins such as gelatin, casein and soybean protein, polyvinylpyrrolidone and their derivatives, acrylic resin, styrene. -Acrylic resin, vinyl acetate resin, vinyl chloride resin, urea resin, urethane resin, alkyd resin, polyester resin, polycarbonate resin, styrene-butadiene latex,
Also, one or more known binders such as their derivatives can be mixed and used.

The mixing ratio of the pigment and binder in the under layer is
More preferably, the binder is 15 to 50 parts by weight with respect to 100 parts by weight of the pigment, and the binder is 20 to 40 parts by weight with respect to 100 parts by weight of the pigment. When a large amount of a binder is used in the under layer, a part of the binder remains adsorbed on the pigment particles even after coating, and the ink absorption capacity of the under layer becomes insufficient. Occurs. For this reason, it is preferable that the amount of the binder is as small as possible so that the surface strength required for the under layer can be secured.

In the support for cast-coated paper for inkjet recording of the present invention, the coating amount of the under layer can be changed according to the purpose, but if the coating amount is increased, the strength of the under layer decreases. A cast coated paper for inkjet recording using a support for cast coated paper for inkjet recording having a low strength of the under layer causes a problem because the amount of cutter paper powder increases. The dry coating amount of the under layer is not specified unless the cutter paper powder amount is increased and does not affect the handling of the inkjet recording cast coated paper which is the final product. From the viewpoint of productivity, it is preferably smaller, and is preferably 20 g / m ² or less. Further, when the coating amount of the under layer is reduced, the ink absorption capacity of the under layer becomes insufficient. Therefore, the coating amount of the under layer is preferably 4 g / m ² or more.

In the present invention, the under layer may optionally contain a pigment dispersant, a water retention agent, a thickener, a defoaming agent, a preservative, a coloring agent, a water resistance agent, a wetting agent, a plasticizer, and a fluorescent dye. Well-known auxiliaries such as a UV absorber, an antioxidant, and a cationic polymer electrolyte can be appropriately blended. From the viewpoint of maintaining the strength of the under layer, it is preferable that the amount of these auxiliaries is 20% by weight or less based on the total weight of the under layer.

In the present invention, various means such as a blade coater, an air knife coater, a roll coater, a curtain coater, a kiss coater, a bar coater, a gate roll coater, and a gravure coater may be used as the means for providing the underlayer on the support. Can be used.

The cast coated paper for ink jet recording of the present invention is provided by a casting method using an aqueous coating liquid containing at least a pigment and a binder on the underlayer surface of the support for cast coated paper for ink jet recording. And an ink receiving layer. As the pigment constituting the ink receiving layer, synthetic amorphous silica, colloidal silica,
Known pigments such as alumina, calcium carbonate, magnesium carbonate, aluminum hydroxide, kaolin, calcined kaolin, talc, titanium dioxide, zinc oxide, and various plastic pigments can be used, and one or more of them can be selected and used. it can. Among them, porous pigments such as synthetic amorphous silica and alumina form a porous layer that is superior in ink absorption compared to other pigments and become relatively transparent in the coating layer. It is preferably used because the color developability of ink is improved when recording is performed on coated paper.

As the binder constituting the ink receiving layer,
Oxidized starch, starches such as esterified starch, carboxymethyl cellulose, cellulose derivatives such as hydroxyethyl cellulose, gelatin, casein, proteins such as soybean protein, polyvinyl alcohol, polyvinylpyrrolidone, acrylic resin, styrene-acrylic resin, vinyl acetate resin, Various known binders such as vinyl chloride resin, urea resin, urethane resin, alkyd resin, polyester resin, polycarbonate resin, styrene-butadiene latex, and derivatives thereof can be used, and one or more kinds can be selected and used. You can

The mixing ratio of the pigment and the binder constituting the ink receiving layer can be changed according to its properties, prescription and support, and should be appropriately set within a range that does not impair the required quality such as ink absorbency. Can be done.

In the cast layer, if necessary, a pigment dispersant, a water retention agent, a thickener, an antifoaming agent, an antiseptic, a coloring agent, a water resistant agent, a wetting agent, a plasticizer, a fluorescent dye, and an ultraviolet absorbing agent. Known auxiliary agents such as an agent, an antioxidant, a release agent, a pH adjuster, and a cationic polymer electrolyte can be appropriately added.

In the cast coated paper of the present invention, the ink receiving layer can be provided by a generally known casting method, but it is particularly preferred that the ink receiving layer is provided by a solidification casting method. In the coagulation method, since the coating layer gels and the degree of plasticization is high, it is possible to obtain a cast layer having less unevenness in gloss and unevenness in adhesion to the drum, and an excellent surface feeling, as compared with the rewet casting method.

As the coagulant used in the coagulation liquid in the coagulation casting method, for example, calcium such as formic acid, acetic acid, citric acid, tartaric acid, lactic acid, hydrochloric acid, sulfuric acid, carbonic acid, zinc, magnesium, sodium, potassium, barium, lead and cadmium. , Salts with ammonium and the like, borax, various borate salts and the like, and one kind or a plurality of kinds can be selected and used.

Particularly in the ink jet recording cast coated paper of the present invention, it is preferable to provide an ink receiving layer containing a large amount of alumina and polyvinyl alcohol in the ink receiving layer. By providing the ink receiving layer on the under layer, the strength of the ink receiving layer is further increased as compared with the case where the ink receiving layer is directly provided on the base paper, and powder falling can be improved. The reason for this is not clear, but it is considered that the ink receiving layer containing a large amount of alumina and polyvinyl alcohol and the under layer firmly adhere to each other.

[0030]

INDUSTRIAL APPLICABILITY In the present invention, even when an ink receiving layer is provided on the under layer of a support by a casting method, it is possible to obtain a cast coated paper for ink jet recording with less powder falling.

[0031]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.
Unless otherwise specified, “%” and “part” described below mean “% by weight” and “part by weight”, respectively.

<Papermaking of base paper> A slurry containing 80 parts of bleached kraft pulp obtained by digesting hardwood and 20 parts of calcium carbonate (Escalon # 800: a product name of Sankyo Flour Milling Co., Ltd.) as a raw material is used. A reticulated paper machine was used to obtain a base paper having a basis weight of 160 g / m ² for the inkjet recording cast-coated paper support of the present invention.

<Production of Support for Cast Coated Paper and Cast Coated Paper for Inkjet Recording> The base layer obtained as described above was coated with the coating liquid for under layer shown below as shown in each example. Then, a support for ink jet recording cast coated paper was obtained. Further, the obtained support was coated with a coating liquid for cast layer as shown in each example to obtain cast coated paper for inkjet recording.

Preparation of coating liquid for under layer (coating liquid 1 for under layer) Synthetic amorphous silica (Syloid ED3, manufactured by Grace Devison Co., oil absorption 300 ml /
100 g) 80 parts, heavy calcium carbonate (Supercoat 95, manufactured by Phimatech, average particle size 0.67 μm,
Ratio of particles having a particle diameter of 2 μm or less: 95.2%) 20 parts, polyvinyl alcohol (PVA-117, manufactured by Kuraray) 25
Part, ethylene vinyl acetate copolymer emulsion: 10 parts of Sumikaflex 401 (manufactured by Sumitomo Chemical Co., Ltd.), 5 parts of cationic ink fixing agent (Polyfix 700, manufactured by Showa Polymer Co., Ltd.), cationic sizing agent (Polymarlon 360, Arakawa) A color having a solid content of 25% was prepared by mixing 5 parts by chemical industry.

(Under Layer Coating Liquid 2) Synthetic Amorphous Silica (Cyloid ED3, Grace Devison Co., Oil Absorption 300 ml / 100 g), Heavy Calcium Carbonate (Super Coat 95, Pharmatech Co., average particle size) 0.67
.mu.m, the proportion of particles having a particle size of 2 .mu.m or less 95.2%) and 8
100 parts by weight of a slurry obtained by dispersing in the presence of a cationic dispersant in a ratio of 0:20 in terms of solid content, polyvinyl alcohol (PVA-117, manufactured by Kuraray) 25 parts, ethylene vinyl acetate copolymer emulsion: Sumikaflex Four
01 (Sumitomo Chemical Co., Ltd.) 10 parts, cationic ink fixing agent (Polyfix 700, Showa High Polymer Co., Ltd.) 5 parts, cationic sizing agent (Polymaron 360, Arakawa Chemical Industry)
A color having a solid content of 25% was prepared by mixing 5 parts.

(Under Layer Coating Liquid 3) Synthetic Amorphous Silica (Cyloid ED3, Grace Devison Co., Oil Absorption 300 ml / 100 g), Heavy Calcium Carbonate (Super Coat 95, Phimatec Co., Average Particle Size) 0.67
μm, the proportion of particles having a particle size of 2 μm or less is 95.2%) and 5
100 parts by weight of a slurry obtained by dispersing in the presence of a cationic dispersant at a ratio of 0:50 in terms of solid content, polyvinyl alcohol (PVA-117, made by Kuraray) 20 parts, ethylene vinyl acetate copolymer emulsion: Sumikaflex Four
01 (Sumitomo Chemical Co., Ltd.) 10 parts, cationic ink fixing agent (Polyfix 700, Showa High Polymer Co., Ltd.) 5 parts, cationic sizing agent (Polymaron 360, Arakawa Chemical Industries)
A color having a solid content of 25% was prepared by mixing 5 parts.

(Under Layer Coating Liquid 4) Synthetic Amorphous Silica (Cyloid ED3, Grace Devison Co., Oil Absorption 300 ml / 100 g), Heavy Calcium Carbonate Slurry (FMT-UF, Phimatec Co., Average Particles) Diameter 0.3
μm, the ratio of particles having a particle size of 2 μm or less is 98%) and 50:
100 parts by weight of a slurry dispersed in the presence of a cationic dispersant at a ratio of 50, calculated as solid content, polyvinyl alcohol (PVA-117, manufactured by Kuraray) 20 parts, ethylene vinyl acetate copolymer emulsion: Sumikaflex 401
25% solid content by mixing 10 parts of (Sumitomo Chemical Co., Ltd.), 5 parts of cationic ink fixing agent (Polyfix 700, Showa High Polymer Co., Ltd.), and 5 parts of cationic sizing agent (Polymaron 360, Arakawa Chemical Industry) Color was prepared.

(Under Layer Coating Liquid 5) Synthetic Amorphous Silica (Cyloid ED3, Grace Devison Co., Oil Absorption 300 ml / 100 g), Heavy Calcium Carbonate (Super Coat 95, Pharmatech Co., Average Particle Size) 0.67
μm, the proportion of particles having a particle size of 2 μm or less is 95.2%) and 2
100 parts of a slurry obtained by dispersing in the presence of a cationic dispersant at a ratio of 0:80 in terms of solid content, polyvinyl alcohol (PVA-117, manufactured by Kuraray) 20 parts, ethylene vinyl acetate copolymer emulsion: Sumikaflex Four
01 (Sumitomo Chemical Co., Ltd.) 10 parts, cationic ink fixing agent (Polyfix 700, Showa High Polymer Co., Ltd.) 5 parts, cationic sizing agent (Polymaron 360, Arakawa Chemical Industry)
A color having a solid content of 25% was prepared by mixing 5 parts.

(Under layer coating liquid 6) Synthetic amorphous silica (Mizukasil P-603, manufactured by Mizusawa Chemical Industry Co., Ltd., oil absorption: 110 ml / 100 g), heavy calcium carbonate (Super Coat 95, manufactured by Pharmatec Co., Ltd., Average particle size 0.67
μm, the proportion of particles having a particle size of 2 μm or less is 95.2%) and 5
100 parts of a slurry obtained by dispersing in the presence of a cationic dispersant at a ratio of 0:50 in terms of solid content, polyvinyl alcohol (PVA-117, manufactured by Kuraray) 20 parts, ethylene vinyl acetate copolymer emulsion: Sumikaflex Four
01 (Sumitomo Chemical Co., Ltd.) 10 parts, cationic ink fixing agent (Polyfix 700, Showa High Polymer Co., Ltd.) 5 parts, cationic sizing agent (Polymaron 360, Arakawa Chemical Industries)
A color having a solid content of 25% was prepared by mixing 5 parts.

(Underlayer coating liquid 7) 100 parts of synthetic amorphous silica (Cyloid ED3, manufactured by Grace Devison, oil absorption 300 ml / 100 g), 25 parts of polyvinyl alcohol (PVA-117, manufactured by Kuraray), ethylene acetic acid Vinyl copolymer emulsion: Sumikaflex 401
25% solid content by mixing 10 parts of (Sumitomo Chemical Co., Ltd.), 5 parts of cationic ink fixing agent (Polyfix 700, Showa High Polymer Co., Ltd.), and 5 parts of cationic sizing agent (Polymaron 360, Arakawa Chemical Industry) Color was prepared.

Preparation of cast layer coating liquid (cast layer coating liquid) High-purity alumina: UA5605 (Showa Denko KK)
50 parts, high purity alumina: AKP-G015 (Sumitomo Chemical Co., Ltd.) 50 parts, polyvinyl alcohol: Denka Poval B-17 (manufactured by Denki Kagaku Co., Ltd.) 5 parts,
Polyvinyl alcohol: PVA624 (made by Kuraray) 5
Part, and 0.2 parts of antifoaming agent, a coating liquid for a cast layer having a solid content concentration of 28% was prepared. (Coagulating liquid) Coagulating agent: Borax / boric acid compounding ratio 0.25 / 1, Na
The concentration of ₂ B ₄ O ₇ and H ₃ BO ₃ is 4%,
Release agent: FL-48C (manufactured by Toho Chemical Industry Co., Ltd.) 0.2%
(Coupling liquid) was blended to prepare a coagulation liquid.

Example 1 Coating solution 1 for under layer was coated on a base paper by a blade method so that the dry coating amount was 8 g / m ² , to produce a cast coated paper support. This support is coated with a cast layer coating liquid using a roll coater so that the dry coating amount is 20 g / m ^2, and while the coating layer is in a wet state, it is solidified with a coagulating liquid. , Then through the press roll 1
It was pressed on a cast drum heated to 05 ° C., the mirror surface was copied, and dried to produce a cast coated paper for inkjet recording. Example 2 A support for cast coating and a cast coated paper for inkjet recording were produced in the same manner as in Example 1 except that the coating liquid 2 for under layer was applied. Example 3 A support for cast coating and a cast coated paper for inkjet recording were produced in the same manner as in Example 1 except that the coating liquid 3 for under layer was applied. Example 4 A support for cast coating and a cast coated paper for inkjet recording were produced in the same manner as in Example 1 except that the coating liquid 4 for under layer was applied.

Comparative Example 1 A support for cast coating and a cast coated paper for inkjet recording were produced by the same method as in Example 1 except that the coating liquid 5 for under layer was applied. Comparative Example 2 An attempt was made to manufacture a support for cast coating and a cast coated paper for inkjet recording by the same method as in Example 1 except that the 6 coating liquid for the under layer was applied.

Comparative Example 3 A support for cast coating and a cast coated paper for ink jet recording were produced in the same manner as in Example 1 except that the coating liquid 7 for under layer was applied. Comparative Example 4 A support for cast coating and a cast coated paper for inkjet recording were produced in the same manner as in Example 1 except that the under layer was not provided.

The cast coated papers for ink jet recording obtained in Examples 1 to 4 and Comparative Examples 1 to 4 were evaluated as follows, and the results are summarized in Table 1. (1) Cutter Paper Powder An A4 width (21 cm) was cut 20 times using an NT cutter, and the amount of paper powder generated was measured. ◯: Paper powder amount is 10 mg or less Δ: Paper powder amount is 10 mg or more, 20 mg or less ×: Paper powder amount is 20 mg or more (2) Ink absorbing ink jet printer (PM-950C: manufactured by Seiko Epson Corporation) of 2880 dpi A pattern in which solid images of magenta and green (mixed color of cyan and yellow) were adjacent to each other at a resolution was printed on an inkjet recording cast coated paper, and bleeding at the boundary portion was visually evaluated according to the following criteria. B: Almost no bleeding is observed at the boundary. B: Bleeding is slightly recognized at the boundary. X: Bleeding is noticeable at the boundary.

[0046]

[Table 1]

As is clear from Table 1, the cast coated paper for ink jet recording of the present invention of Examples 1 to 4 was able to obtain good results in both cutter paper powder and ink absorbency. On the other hand, in Comparative Example 1 in which the compounding ratio of synthetic amorphous silica is small and in Comparative Example 2 in which the amount of synthetic amorphous silica oiled is small, the ink absorbency is particularly poor, and in Comparative Example 3 in which heavy calcium carbonate is not compounded. Especially the cutter paper powder was inferior. Further, in Comparative Example 4 in which the under layer was not provided, both the cutter paper powder and the ink absorbency were poor.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shoichi Endo             5-21-1 Oji, Kita-ku, Tokyo Nippon Paper Industries             Product Research Institute Co., Ltd. (72) Inventor Jiro Yoshimura             5-21-1 Oji, Kita-ku, Tokyo Nippon Paper Industries             Product Research Institute Co., Ltd. F-term (reference) 2C056 EA13 FC06                 2H086 BA01 BA15 BA17 BA31 BA33                       BA45 BA47                 4L055 AG11 AG18 AG59 AG64 AG89                       AG97 AH02 AH37 AJ04 BE08                       EA10 EA16 EA32 FA15 FA30                       GA09

Claims (3)

[Claims] 1. A cast coated paper support for ink jet recording comprising at least one underlayer containing a pigment and a binder on at least one side of a base paper, wherein the pigment in the underlayer has an oil absorption of 200 ml. / 100 g or more of synthetic amorphous silica (A) and heavy calcium carbonate (B) containing 95% by weight or more of particles having a particle diameter of 2 μm or less, and the synthetic amorphous silica and heavy material in the under layer A support for cast-coated paper for inkjet recording in which the weight ratio of calcium carbonate is A: B = 50: 50 to 80:20. 2. An oil absorption amount of 200 on at least one side of a base paper.
By applying a coating liquid containing a pigment dispersion liquid in which at least ml of synthetic amorphous silica and ground calcium carbonate containing 95% by weight or more of particles having a particle diameter of 2 μm or less are dispersed in the presence of a cationic dispersant. The cast coated paper support for ink jet recording according to claim 1, wherein an under layer is formed. 3. A casting method using an aqueous coating liquid containing at least a pigment and a binder on the under layer of the support for ink jet recording cast coated paper according to claim 1 or 2. A cast-coated paper for ink jet recording having an ink receiving layer formed thereon.