JP2000141868A - Ink jet recording sheet and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording sheet for holding high glossiness, a sense of gloss and smoothness near those of a photograph, high printing density, excellent printing water resistance, excellent fixability, absorbency and the like of an ink jet ink on an uppermost recording surface. SOLUTION: In the ink jet recording sheet comprising an ink jet cast coat layer 3 formed by a wetting method on one surface of a base sheet 1 through an ink jet undercoating layer 2 and an ink jet cast gloss layer 4 sequentially laminated by a re-wetting method in such a manner that 60-degree mirror surface glossiness according to JIS Z 8741 of the outermost surface is 60 to 80%, the pigment for constituting an ink jet undercoating layer is a silica and/or light calcium carbonate, and as an additive, a cationoid reagent is contained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photo grade ink jet recording paper and a method for producing the same.

[0002]

2. Description of the Related Art Ink jet printers, which jet liquid ink from a nozzle having a special structure in a jet form, control the trajectory of the ink, and apply the ink to paper to print such as a facsimile, a word processor, and a personal computer, are widely used. Have been. In addition, the paper used for this includes the fixing properties and absorbency of the inkjet ink, the print density, the roundness of the dot shape, the sharpness around the dots, the glossiness, the whiteness, the water resistance, and the dimensions due to moisture absorption and desorption. Ink jet recording paper having various properties such as stability is used.

[0003] However, in the ink jet recording paper, especially for photo grades, the characteristics of the recording surface thereof include high glossiness, gloss smoothness close to that of photographs, high print density, and excellent ink jet ink fixability. There is a demand for ink-jet recording paper having high absorbency and absorbency.

[0004] As a method for imparting such higher properties, PVA, polyvinylpyrrolidone, polyurethane or the like is used as a surface treatment agent on the surface of a high gloss printing paper such as art paper or cast coated paper which is usually used. A method of directly applying an aqueous resin or emulsion such as polyvinyl acetal, or directly applying the aqueous resin or emulsion to the surface of a polyester film, and the coated surface is in a semi-dry wet state. Sometimes, high-quality paper and the like are overlaid and dried as it is, and after drying, the polyester film is peeled off to form a film of the aqueous resin or emulsion on the surface of the high-quality paper or the like, and at the same time, the surface gloss and smoothness of the polyester film are reduced. Improving the film transfer method for copying and the coating composition of the cast coat layer of cast coated paper And a method of imparting properties to the paper itself.

[0005]

However, in the above-mentioned method of directly applying an aqueous resin or an emulsion, a certain degree of gloss and smoothness can be obtained by selecting the resin, but the absorption of ink-jet ink can be improved. Slows down, causing blocking of inkjet ink,
Blending of the ink-jet ink occurs at the overlapped portions of the ink-jet inks or at the boundary surface between the ink-jet inks, and rubbing occurs during running in the printer due to poor absorption of the ink-jet ink, so that satisfactory ink cannot be obtained.

In the above-mentioned film transfer method, the state of the surface of the polyester film is copied. This also provides a certain degree of glossiness and smoothness. However, it depends on the glossiness and smoothness of the film itself. It is easy to cause partial unevenness or unevenness on the transferred surface, and it is difficult to obtain a glossy smoothness like a photograph.

Further, various studies have been made on the improvement of the coating composition of the cast coat layer with respect to selection of a pigment, selection of an adhesive, selection of various additives, and the like. Things have not been obtained.

Therefore, the present inventors have reexamined the pigments in the cast coat coating composition, and have also tried to reexamine the layer formation of the cast coated paper.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned disadvantages of the prior art, and to provide a high glossiness on a recording surface of an ink jet recording paper, a glossy smoothness close to that of a photograph, a high print density, excellent print water resistance and excellent ink jet ink. An object of the present invention is to provide an ink jet recording paper having a fixing property, an absorbability and the like, and a method for producing the same.

[0010]

Means for Solving the Problems In order to achieve the object of the present invention, as an ink jet recording paper, first, an ink jet undercoat layer formed on one surface of a base paper is interposed with an ink jet cast coat layer. Ink-jet gloss layer is sequentially laminated and the outermost surface is JIS-
In an ink jet recording paper having a 60-degree specular glossiness of 60 to 80% according to Z-8741, the pigment constituting the ink jet undercoat layer is silica and / or light calcium carbonate, and contains a cationizing agent as an additive. Secondly, the pigment constituting the inkjet cast coat layer is γ-alumina and contains a cationic emulsion as an additive. Thirdly, the pigment constituting the glossy inkjet cast layer is anionic colloidal silica. The gist is that

[0011] In addition, as a method for producing an ink jet recording paper, an ink jet undercoat containing silica and / or light calcium carbonate as a pigment and a cationizing agent as an additive is coated on one side of a base paper in dry conversion. ~
20 g / m ² coated and dried to form an undercoat layer. On the ink jet undercoat layer, γ-alumina is used as a pigment by a wet method using a cast coater, and a cationic emulsion is contained as an additive. The ink-jet cast coat paint to be applied is coated in a dry conversion of 4 to 15 g / m ² and dried to form an ink-jet cast coat layer. Then, the ink is cast as a pigment on the ink-jet cast coat layer by a re-wetting method using a cast coater. An inkjet cast gloss coating using anionic colloidal silica is applied at a dry conversion of 0.1 to 5 g / m ² and dried to form an inkjet cast gloss layer, and a 60 ° mirror surface according to JIS-Z-8741 on the outermost surface. The gist is that the glossiness is 60 to 80%.

According to the first aspect of the present invention, a cast coating layer formed of two layers, an ink-jet cast coat layer and an ink-jet cast gloss layer, interacts on the ink-jet undercoat layer. The outermost surface is
60-degree specular gloss according to JIS-Z-8741
An ink jet recording paper having characteristics such as high glossiness of 80%, gloss smoothness close to that of a photograph, high print density, excellent print water resistance and excellent fixability and absorbency of the inkjet ink.

That is, if any one of the ink-jet cast coat layer and the ink-jet cast gloss layer is formed, no ink-jet recording paper having the above characteristics can be obtained.

The ink jet undercoat layer covers the surface of the base paper and smoothes it, and improves the smoothness of the ink jet cast coat layer and the ink jet cast gloss layer formed thereon.

[0015] In particular, the ink jet undercoat layer improves the color density of the ink jet ink by containing a cationizing agent as an additive. Furthermore, the formation of the ink jet undercoat layer reduces the variation in air permeability, and further improves the cast workability when forming the ink jet cast coat layer and the ink jet cast gloss layer formed thereon.

According to the second aspect of the present invention, in addition to the above-described functions, the ink-jet cast coat layer absorbs the ink-jet ink without fail, and is formed thereon without causing rubbing, blocking, and stickiness. The effect of the properties of the inkjet cast gloss layer can be made more effective.

Furthermore, since the ink-jet cast coat layer contains γ-alumina, which is a cationic alumina hydrate, and a cationic emulsion, an anion in the ink-jet cast gloss layer formed on the ink-jet cast coat layer is formed. Strong bonding can be obtained by electrical coupling with the colloidal silica.

According to the third aspect of the present invention, when the inkjet cast gloss paint is applied on the inkjet cast coat layer, that is, when used as a rewet paint, the inkjet cast gloss paint is already formed. While wetting and swelling the inkjet cast coat layer, the colloidal silica of fine particles used for the pigment of the inkjet cast gloss paint,
By entering into the fine cracks and irregularities of the inkjet cast coat layer to form a smoother inkjet cast gloss layer and the properties of the inkjet cast gloss paint itself, high glossiness and glossy smoothness close to photographs are obtained. It is presumed to be obtained.

Further, since the colloidal silica used for the inkjet cast gloss layer is anionic, the cationic alumina hydrate contained in the lower inkjet cast coat layer, γ-
Due to the electrical coupling with the alumina and the cationic emulsion, strong adhesion can be obtained without using an adhesive in the inkjet cast gloss paint.

According to the fourth aspect of the present invention, since the inkjet cast gloss layer is formed by the rewetting method on the inkjet cast coat layer formed by the wet method, the coating speed during the formation of the inkjet cast gloss layer is reduced. In addition, the cast surface can be easily formed and stable workability can be obtained. In addition, it is possible to easily and inexpensively manufacture an ink jet recording paper having the above-mentioned characteristics in terms of quality.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the ink jet recording paper and the method for producing the same according to the present invention will be described below. FIG. 1 is a vertical side view of the ink jet recording paper of the present invention.

As shown in FIG. 1, the inkjet recording paper of the present invention comprises an inkjet cast coat layer 3 and an inkjet cast gloss layer 4 via an inkjet undercoat layer 2 formed on one surface of a base paper 1. It has a four-layer structure in which a plurality of cast layers are sequentially laminated, and has a 60-degree specular glossiness according to JIS-Z-8741 of 60 to 80% on the outermost surface.

The base paper 1 is appropriately selected and used from high quality paper, medium quality paper, base paper for art-coated paper, base paper for cast-coated paper, finely coated paper, and the like. The basis weight of the base paper 1 is usually about 30 to 250 g / m ² .

The ink-jet undercoat layer 2 is formed by coating the ink-jet undercoat paint on one surface of the base paper 1 with a dry conversion of 5 to 5.
The coating is dried to about 20 g / m ² , and after drying, a smoothing treatment is performed as necessary. The composition of the ink jet undercoat composition mainly contains a pigment, an adhesive, and a cationizing agent, and a dispersant, a viscosity modifier, a crosslinking agent, and the like are appropriately added and used as needed.

The purpose of forming the ink jet undercoat layer 2 is to cover and smooth the surface of the base paper 1 and to improve the smoothness of the ink jet cast coat layer 3 and the ink jet cast gloss layer 4 formed thereon. ,
Improving the print color density of the ink-jet ink, and reducing the variation in air permeability to improve the cast workability when forming the ink-jet cast coat layer 3 and the ink-jet cast gloss layer 4 formed thereon. .

As the pigment for the ink jet undercoat layer 2, silica, colloidal silica, alumina hydrate, kaolin, calcium carbonate, titanium dioxide, zinc oxide, satin white, and organic pigments can be used alone or in combination. Considering the price and the like, silica and light calcium carbonate are particularly preferably used.

Examples of the adhesive for the ink jet undercoat layer 2 include water-soluble resins such as PVA, polyvinylpyrrolidone, CMC, hydroxyethylcellulose, casein, gelatin, starch and sodium alginate, and vinyl acetate, vinyl chloride-vinyl acetate copolymer. And an emulsion of a synthetic resin such as styrene-butadiene copolymer, polyurethane, acrylic copolymer, and maleic acid copolymer. These are appropriately selected, and an appropriate amount is used alone or in combination.

The following are used as the cationizing agent added to the ink jet undercoat layer 2. That is, salts of primary, secondary or tertiary amines, such as laurylamine acetate and stearylamine acetate. Quaternary ammonium salt type compounds such as lauryltrimethylammonium chloride and lauryldimethylammonium chloride. Cationic high molecular compound: for example, polyallylamine hydrochloride, polydimethylaminoethyl methacrylate,
Polydiethylaminoethyl acrylate and the like. Monomers having a cationic group alone or copolymers with other substances ... for example, diethylaminostyrene. In addition, polyalkylene polyamines, secondary amines, tertiary amines, acrylic resins having a quaternary ammonium group, dicyandiamide resins, and the like can be used. The amount used depends on the pigment selected, but is usually added to about 4 to 20% of the pigment.

As a smoothing treatment of the ink jet undercoating layer 2 to be processed as required, a coating is carried out by passing between roll nips using a commonly used super calender, gloss calender, thermoplier or the like. The surface of the layer is smoothed.

Next, the ink jet cast coat layer 3
Is applied on the ink jet undercoat layer 2 to form an ink jet cast coat paint in a dry conversion of 4 to 15
It is formed by coating and drying to about g / m ² . The composition of the ink-jet cast coating composition mainly includes a pigment, an adhesive, a cationic emulsion, and a release agent, and a dispersant, a viscosity modifier, a crosslinking agent, and the like are appropriately added and used as needed.

The purpose of forming the ink-jet cast coat layer 3 is to maintain excellent absorptivity of the ink-jet ink, and to provide a high glossiness, a gloss smoothness close to a photograph, and a high gloss by the ink-jet cast gloss layer 4 formed thereon. This is because the print density and the excellent fixability of the inkjet ink are more effectively exhibited.
By the way, if the inkjet cast gloss paint is directly applied on the inkjet undercoat layer 2 without forming the inkjet cast coat layer 3, JIS-Z
The 60-degree specular glossiness according to -8741 is only about 35% or less, and the original purpose cannot be achieved.

Further, the inkjet cast coat layer 3
Contains γ-alumina, which is a cationic alumina hydrate, and a cationic emulsion, so that the anionic colloidal used for the inkjet cast gloss layer 4 formed on the inkjet cast coat layer 3 is used. Strong bonding can be obtained by electrical coupling with silica.

As the pigment for the ink-jet cast coat layer 3, alumina hydrate, fine-particle silica or the like is used. In particular, when the cast surface is formed, the higher the concentration of the cast paint used, the better the work surface and the quality. Γ- which is a cationic alumina hydrate
Alumina is preferably used.

As the adhesive for the ink-jet undercoat layer 3, the same adhesive as the ink for the ink-jet undercoat used for forming the ink-jet undercoat layer 2 can be used. These adhesives are appropriately selected, and an appropriate amount is used alone or in combination.

As the cationic emulsion of the ink-jet cast coat layer 3, a cationically modified synthetic resin emulsion such as a cationized vinyl acetate emulsion, a urethane emulsion and an acrylic emulsion is preferable.

The release agent of the ink-jet cast coat layer 3 is added for the purpose of smoothly peeling the coated surface from the chromium-plated cast drum. Fatty acids, fatty acid salts, various wax emulsions and the like are appropriately added. And used alone or in combination. However, when these release agents are used in a large amount, they cause a decrease in the absorbability of the inkjet ink. Therefore, the balance between the peeling state of the coated surface and the decrease in the absorbency of the inkjet ink is to be comprehensively considered. Use the appropriate amount taken.

Next, the ink jet cast gloss layer 4
Laminated on the above-mentioned inkjet cast coat layer 3, the inkjet cast glossy paint is 0.1% in dry conversion.
５5 g / m ² is formed by coating and drying. The composition of the ink-jet cast gloss paint mainly includes a pigment and a release agent, and a dispersant, a viscosity modifier, a cross-linking agent and the like are appropriately added and used as necessary.

The purpose of forming the inkjet cast glossy layer 4 is to form the outermost surface of the glossy layer 4 according to JIS-Z-8741.
The purpose is to maintain high glossiness of 60 to 80% in terms of 0 degree specular glossiness, gloss and smoothness close to a photograph, high print density, excellent fixability of inkjet ink, and the like. Further, since the ink-jet cast gloss layer 4 uses anionic colloidal silica, the ink-jet cast gloss layer 4 is mixed with the cationic alumina hydrate γ-alumina and the cationic emulsion contained in the lower ink-jet cast coat layer 3. By the electric connection, a strong bond can be obtained without using an adhesive for the inkjet cast gloss paint.

As the pigment for the ink-jet gloss layer 4, fine-particle silica, colloidal silica having a particle size of 500 nm or less is used, and anionic colloidal silica having a particle size of 500 nm or less is particularly preferably used.

As the release agent for the inkjet cast gloss layer 4, the same release agent as that used in the above-mentioned inkjet cast coat paint is used. It is appropriately selected and used alone or in combination. When the state where the mold is released from the cast drum and the state where the absorptivity of the ink-jet ink is impaired are comprehensively used, an appropriate amount that balances both is used.

Next, a method for producing the ink jet recording paper of the present invention will be described. First, as a first step, an ink jet undercoat of the above composition is applied to one surface of a roll-shaped base paper 1 by a coating machine, for example, a blade coater, an air knife coater, a reverse coater, a bar coater, a gravure coater, a die coater or the like. The coating composition is applied to a dry conversion of 5 to 20 g / m ² and dried to form an ink jet undercoat layer 2 and wound into a roll.

Here, the coating of the ink jet undercoat may be a single coating or a coating of two or more coatings, and it is preferable to apply the ink in multiple layers because the coating becomes smoother. If necessary, the surface to be coated with the ink jet undercoat may be further smoothed by a smoothing machine, for example, a super calender, a gloss calender, or a thermo punisher.

Next, as a second step, the ink jet undercoat layer 2 is formed on the rolled-up ink-jet undercoat layer 2 by a wet method using a cast coater so that the ink-jet cast coat paint becomes ⁴ to 15 g / m ² in dry conversion. To the chrome-plated cast drum,
At the same time as drying, the mirror surface is transferred to form the inkjet cast coat layer 3 and wound up in a roll.

Further, as a third step, the ink-jet cast glossy paint, that is, the rewet paint, is converted to a dry paint by a rewetting method with a cast coater at a dry conversion of 0.1 to 0.1.
5 g / m ² , and the already formed ink-jet cast coat layer 3 is wetted and swelled. In the swollen state, the ink-jet cast coat layer 3 is pressed against a chromium-plated cast drum in the same manner as in the previous term, dried, and mirror-finished. Is transferred to form an ink-jet gloss layer 4, which is wound into a roll to obtain the ink-jet recording paper of the present invention.

Next, the casting method for producing cast paper will be described. Generally, three methods are known: a wet method, a gelling method, and a rewetting method.

That is, the wet method is also referred to as a direct method, in which the base paper is coated with a cast paint as described above, and the base paper is pressed against the cast drum in a wet state. This is a method of copying a mirror surface.

The gelling method is also called a coagulation method, in which a base paper is coated with a cast paint, and the wet coating layer is treated with an aqueous solution of an acid or salt to gel the coating layer. This is a method of pressing the cast drum against the cast drum in a state where the cast drum is dried, and simultaneously copying the mirror surface of the cast drum with drying.

In the rewetting method, after a base paper is coated with a cast paint and dried, the surface is smoothed by a super calender or the like, and then the coated layer is wetted and swelled again with an aqueous solution of a phosphate or the like to swell. This is a method in which the surface of the cast drum is pressed against the cast drum in a state of being dried, and the mirror surface of the cast drum is copied at the same time as drying.

These methods are widely recognized, and a slight difference is maintained in the quality of cast paper obtained by each method. In the present invention, as a result of testing by each method, by applying the rewetting method to the formation of the inkjet cast gloss layer 4, the coating speed at the time of forming the inkjet cast gloss layer 4 is increased, and the formation of the cast surface is improved. Easy to do,
The method is employed because stable workability can be obtained, and the obtained quality can be optimally applied to inkjet recording paper for photo grade.

[0050]

Next, the present invention will be described in detail with reference to Examples and Comparative Examples, which are intended to specifically explain the effects of the present invention, and are not intended to limit the present invention. is not.

<Example 1> 113 g / m ² as base paper 1
As a first step, using an air knife coater as a coater, the following ink-jet undercoat composition was coated and dried to a dry conversion of 15 g / m ² using a base paper for coated paper of The undercoat layer 2 was formed and wound into a roll. After drying, it was smoothed by a super calender under the condition of a linear pressure of 150 kg / cm, and wound up again in a roll. <Ink-jet undercoat composition> (Indicated by dry weight) Carplex BS304N (Silica, manufactured by Shionogi & Co., Ltd.) 100 parts by weight Pateracol IJ50 (Urethane emulsion, manufactured by Dainippon Ink and Chemicals, Inc.) 17 parts by weight Pateracol D302 (Urethane Emulsion, Dainippon Ink and Chemicals, Inc.) 12 parts by weight PVA217 (PVA, Kuraray) 10 parts by weight PAS-H-10L (cationizing agent) (diallyldimethylammonium chloride polymer, Nitto Boseki) 7 parts by weight With the above composition, an ink jet undercoat having a coating concentration of 20% was prepared.

Next, as a second step, the following ink-jet cast coat coating composition was dried on the ink-jet undercoat layer 2 whose surface was smoothed by an air knife coater of a cast coating machine at 13 g / dry equivalent. m ² , pressed in a wet state on a chrome-plated cast drum, dried and simultaneously transferred the mirror surface of the cast drum to form an inkjet cast coat layer 3 and wound up in a roll. . <Inkjet coating composition> (Displayed in dry parts) AKP-G015 (γ-alumina, manufactured by Sumitomo Chemical Co., Ltd.) 100 parts by weight Acetic acid (commercially available reagent product) 4 parts by weight PVA210 (PVA, manufactured by Kuraray Co., Ltd.) 12 parts by weight Ultrasol SIX11 (cationic acrylic emulsion, manufactured by Ganz Kasei Co., Ltd.) 8 parts by weight Cerosol 524 (release agent, carnauba wax, manufactured by Chukyo Yushi Co., Ltd.) 1 part by weight Paint was created.

Further, the ink jet cast coat layer 3
In a third step, the following inkjet cast glossy paint composition was applied by a bar coater of a rewet method cast coater so as to have a dry conversion of 0.1 g / m ² , to thereby form an already formed ink. Inkjet coat layer 3
Is wetted and swelled, and is pressed against a chrome-plated cast drum while in the swollen state, and dried, and at the same time, a mirror surface of the cast drum is transferred to form an ink-jet cast gloss layer 4, which is wound into a predetermined size. Example 1 according to the present invention having a basis weight of 141.1 g / m ²
Was obtained. <Inkjet gloss coating composition> (Indicated by dry weight) Snowtex O (Colloidal silica, manufactured by Nissan Chemical Industries, Ltd.) 20 weight parts Ammonium oleate (release agent, commercial product) 5 weight parts Paint concentration 3 % Of an inkjet cast gloss paint.

<Example 2> The following ink-jet cast coat paint composition was applied on the ink-jet undercoat layer 2 obtained in Example 1 and having a smoothed surface by an air knife coater of a wet-type cast coater. To a dry conversion of 15 g / m ^2, and pressed against a chrome-plated cast drum in a wet state,
At the same time as drying, the mirror surface of the cast drum was transferred to form an inkjet cast coat layer 3, which was wound into a roll. <Inkjet coating composition> (Displayed in dry parts) AKP-G015 (γ-alumina, manufactured by Sumitomo Chemical Co., Ltd.) 100 parts by weight Acetic acid (commercially available reagent product) 4 parts by weight PVA210 (PVA, manufactured by Kuraray Co., Ltd.) 12 parts by weight Polytron X3601.01 (cation-modified acrylic latex, manufactured by Asahi Kasei Kogyo) 8 parts by weight Cerosol 524 (release agent, carnauba wax, manufactured by Chukyo Yushi Co., Ltd.) 1 part by weight A coat paint was created.

Further, the inkjet cast coat layer 3
As a third step, the following inkjet cast gloss coating composition was applied by a bar coater of a re-wet casting coater so as to be 5 g / m ² in dry conversion, and the already formed inkjet coat was coated. The layer 3 is wetted and swelled, and the swelled state is pressed against a chrome-plated cast drum and dried, and at the same time, the mirror surface of the cast drum is transferred to form an ink-jet cast gloss layer 4 and wound up to a predetermined size. Then, an ink jet recording paper of Example 2 having a basis weight of 148 g / m ² according to the present invention was obtained. <Inkjet glossy paint composition> (Indicated by dry weight) Cataloid SI30 (Colloidal silica, manufactured by Catalyst Kasei Kogyo) 30 wt. Parts Ammonium oleate (release agent, commercial product) 6 wt. Ink-jet gloss paint was prepared.

Comparative Example 1 The ink-jet recording paper of Comparative Example 1 was the one obtained in Example 1 up to the formation of the ink-jet cast coat layer 3 in the second step. (141 g / m grammage
² )

<Comparative Example 2> On the ink-jet cast coat layer 3 obtained in the second step of Example 1, the same ink-jet cast coat paint composition as in Example 1 was applied at a paint concentration of 15%. Using a bar coater of a cast coating machine, the coating amount was 5 g / m ^{2 in} dry conversion.
Other than that, an ink jet recording paper of Comparative Example 2 was prepared in the same manner as in Example 1. (Basic weight 146 g / m ² )

Using the ink jet recording papers obtained in Examples 1 and 2 and Comparative Examples 1 and 2 as test samples, each of the following measurement items was measured by the corresponding measuring method, and the results were obtained. Are summarized in Table 1.

<Test Items and Test Methods> Gloss The specular gloss of 60 degrees according to JIS-Z-8741 on the outermost surface is measured. The unit is expressed in%.

2. Print density Using the Epson printer PM-700C on the outermost surface, using the specified ink black, printing a standard test chart with a special gloss film as the print mode,
24 hours after printing, the density of the designated printing portion (black) is measured by the Macbeth densitometer RD915.

3. Print Water Resistance The standard test chart is printed on the outermost surface using an Epson printer PM-700C, using a designated ink, and a special gloss film as a print mode. Drops are dropped, and after 10 seconds, rubbed lightly with tissue paper three times, and visually observe whether or not the ink is eluted into the tissue paper. (Judgment criteria) A: Very good.・ ・ ・: Excellent. △: Normal. ×: Inferior. XX: Very poor.

4. Water resistance of the recording paper One drop of water is dropped on the outermost surface, and 10 seconds later, it is rubbed lightly 10 times with a fingertip, and the presence or absence of elution of the paint is visually observed. (Judgment criteria) A: Very good.・ ・ ・: Excellent. △: Normal. ×: Inferior. XX: Very poor.

5. Absorbency of ink The above-mentioned Epson printer PM-700C
Using the designated ink, printing is performed with a special gloss film as a printing mode as a printing mode, and the printed surface is rubbed and the presence or absence of bleeding of ink in a heavy color portion is visually observed. (Judgment criteria) A: Very good.・ ・ ・: Excellent. △: Normal. ×: Inferior. XX: Very poor.

6. Gloss smoothness The glossy smoothness on the outermost surface is visually judged according to the following five steps. (Judgment criteria) A: Very good.・ ・ ・: Excellent. △: Normal. ×: Inferior. XX: Very poor.

<Results of Test>

[Table 1]

As can be seen from the above test results, the quality of Examples 1-2 of the ink jet recording paper of the present invention was
It can be seen that the quality is extremely excellent in any of the items as compared with the quality of Comparative Examples 1 and 2.

[0067]

As described above, the ink jet recording paper and the method for producing the same according to the present invention can be used as the ink jet recording paper obtained through the ink jet undercoat layer formed on one surface of the base paper and the ink jet cast coat layer. And the inkjet coating gloss layer and the cast coating layer formed in two layers interact with each other, and the outermost surface is
It has high glossiness, gloss and smoothness close to that of photographs, high print density, and excellent print water resistance, and can maintain excellent properties such as excellent fixability and absorbency of the inkjet ink.

Further, the ink jet undercoat layer can cover the surface roughness of the base paper and make it smooth, improve the smoothness of the ink jet cast coat layer and the ink jet cast gloss layer formed thereon, Increasing the color density of the ink-jet ink by containing the agent, the dispersion of air permeability is reduced by forming the ink-jet undercoat layer, when forming the ink-jet cast coat layer and the ink-jet cast gloss layer formed thereon Improve casting workability.

The ink jet cast coat layer absorbs the ink jet ink without fail, and effectively exerts the properties of the ink jet cast gloss layer formed thereon without causing rubbing, blocking or stickiness. And

Furthermore, the ink-jet cast coat layer contains γ-alumina, which is a cationic alumina hydrate, and a cationic emulsion, so that it is contained in the ink-jet cast gloss layer formed on the ink-jet cast coat layer. Strong bonding can be obtained by electrical bonding with the anionic colloidal silica to be performed.

Further, the inkjet cast gloss layer is
When the inkjet cast gloss paint is coated on the inkjet cast coat layer, that is, when used as a rewet paint, the inkjet cast gloss paint wets and swells the already formed inkjet cast coat layer, and the ink jet ink. The colloidal silica of the fine particles used in the pigment of the cast gloss paint penetrates into fine cracks and irregularities of the inkjet cast coat layer, making the inkjet cast coat layer smoother, and the characteristics of the inkjet cast gloss paint itself. Are presumed to obtain high glossiness and gloss smoothness close to that of a photograph.

Further, since the colloidal silica used for the inkjet cast gloss layer is anionic, as described above, the cationic alumina hydrate γ-alumina and the cationic alumina contained in the lower inkjet cast coat layer are used. By means of the electrical connection with the emulsion, strong adhesion can be obtained without using an adhesive in the inkjet cast gloss paint.

Further, since the ink-jet cast gloss layer was formed on the ink-jet cast coat layer formed by the wet method by the re-wet method, the coating speed at the time of forming the ink-jet cast gloss layer was increased,
The surface of the cast surface can be easily formed, stable workability can be obtained, and the ink jet recording paper maintaining the above-mentioned various characteristics in terms of quality can be easily and inexpensively manufactured.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view of an ink jet recording paper of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Base paper 2 ... Inkjet undercoat layer 3 ... Inkjet cast coat layer 4 ... Inkjet cast gloss layer

Claims (4)

[Claims] 1. An ink-jet cast coat layer and an ink-jet cast gloss layer are sequentially laminated via an ink-jet undercoat layer formed on one surface of a base paper, and the outermost surface thereof has a 60-degree specular gloss according to JIS-Z-8741. In the ink jet recording paper having a degree of 60 to 80%,
The pigment constituting the ink jet undercoat layer is silica and / or
Or an ink jet recording paper which is light calcium carbonate and contains a cationizing agent as an additive. 2. The ink jet recording paper according to claim 1, wherein the pigment constituting the ink jet cast coat layer is cationic γ-alumina, and contains a cationic emulsion as an additive. 3. The ink jet recording paper according to claim 1, wherein the pigment constituting the ink jet cast gloss layer is anionic colloidal silica. 4. An ink jet primer containing silica and / or light calcium carbonate as a pigment and a cationizing agent as an additive is coated on one side of the base paper in an amount of 5 to 20 g / m ^{2 in} terms of dry weight, and dried. To form an undercoat layer,
On the ink jet undercoat layer, a wet coating method using a cast coater was used, and the ink-jet cast coat paint containing a cationic γ-alumina as a pigment and a cationic emulsion as an additive was converted to a dry paint by 4 to 4 wt.
15 g / m ² coated and dried to form an inkjet cast coat layer, and then an inkjet cast gloss using an anionic colloidal silica as a pigment on the inkjet cast coat layer by a rewetting method using a cast coater. Paint is 0.1 to 5 in dry conversion
g / m ² coated and dried to form an inkjet cast gloss layer, and the outermost surface has a 60 ° specular glossiness of 60 to 80% according to JIS-Z-8741. .