JP2000211248A - Manufacture of ink jet recording paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure high glossiness, printing property and durability or the like on a recorded surface by forming an ink jet cast coat application layer on an ink jet undercoat layer, and applying an ink jet cast gloss coating by a rewet method of a cast coating machine after the surface of the ink jet cast coat application layer has been smoothened. SOLUTION: An ink jet cast coat application layer 3 and an ink jet cast gloss layer 4 are laminated in order through an ink jet undercoat layer 2 which is formed on the surface of a base paper 1, and a four layer body structure is formed. The, the 60 deg. mirror finish surface glossiness by JIS-Z-8741 of the outermost surface is set at 60-80%. Also, the ink jet undercoat layer 2 is formed by applying and drying an ink jet undercoat coating by a 5-20 g/m2 by a dry conversion. In addition, the coat application layer 3 is formed by applying and drying a coat coating by a range of 4-15 g/m2 by a dry convertion, and the cast gloss layer 4 is formed by applying and drying a gloss coating by a range of 0.1-5 g/m2 by a dry convertion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[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.

Accordingly, the present inventors have reexamined the pigments in the cast coat coating composition and tried to reexamine the method of forming a layer of 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. It is an object of the present invention to provide a method for manufacturing an ink jet recording paper that retains fixability and absorbability.

[0010]

In order to achieve the object of the present invention, an ink jet undercoat containing silica and / or light calcium carbonate as a pigment and a cationizing agent as an additive on one surface of a base paper. In dry conversion
20 g / m ^{2 is} applied and dried to form an undercoat layer. On the ink-jet undercoat layer, an ink-jet cast coat paint containing γ-alumina as a pigment and a cationic emulsion as an additive is converted to a dry coating. 4 to 15 g / m ² and dried to form an ink-jet cast coat layer, followed by a smoothing treatment. Anionic cast colloidal silica is used as an additive, and an inkjet cast gloss paint (that is, a rewet paint) using a release agent as an additive is applied in an amount of 0.1 to 5 g / m ² in dry conversion, and dried to form an inkjet cast gloss layer. By doing so, the 60 ° specular gloss of the outermost surface according to JIS-Z-8741 is 60% to 80%. It is an gist obtaining a Kujetto recording paper.

According to the present invention, an ink jet cast coat layer is formed on the ink jet undercoat layer, the surface thereof is smoothed, and then the ink jet cast gloss paint is applied by a rewetting method using a cast coater. In addition, the ink jet cast coat paint layer and the ink jet cast gloss paint layer interact with each other, so that the outermost surface is JIS-Z-87.
High glossiness of 60 to 80% in 60 degree specular glossiness according to 41, glossy smoothness close to photograph, high print density, excellent print water resistance, and excellent properties such as excellent fixability and absorbency of inkjet ink. It becomes inkjet recording paper.

That is, if the ink-jet cast gloss layer is formed by applying the ink-jet cast gloss paint by a rewetting method without forming a smoothing treatment after forming the ink-jet cast coat layer, the above-mentioned characteristics are maintained. No obtained ink jet recording paper can be obtained.

[0013] Even if the cast layer is formed of any one of the inkjet cast coat paint layer and the inkjet cast gloss paint layer, it goes without saying that
An ink jet recording paper having the above characteristics cannot be obtained.

The ink jet undercoat layer covers and smoothes the roughness of the base paper, and the ink jet cast coat paint layer formed thereon is smoothed. Improve the performance.

Further, the ink jet undercoat layer improves the color density of the ink jet ink by containing a cationizing agent as an additive. Further, the formation of the ink jet undercoat layer reduces the variation in air permeability, and improves the cast workability when forming the ink jet cast glossy layer with a cast coating machine.

Next, the ink-jet cast coating 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. It can be.

Further, since the ink-jet cast coat paint layer contains γ-alumina which is a cationic alumina hydrate and a cationic emulsion, the ink-jet cast gloss paint is coated on the ink-jet cast coat paint layer. Strong adhesion can be obtained by electrical bonding with the anionic colloidal silica in the inside.

Further, according to the present invention, after forming an ink-jet cast coat paint layer on the ink-jet undercoat layer, the surface thereof was subjected to a smoothing treatment prior to coating of the ink-jet cast gloss paint with a cast coater. Thereby, a high smoothness can be imparted to the outermost surface of the obtained inkjet recording paper.

Further, in addition to the above-mentioned smoothing treatment, when the inkjet cast gloss paint is coated on the inkjet cast coat paint layer, the inkjet cast gloss paint wets the already formed inkjet cast coat paint layer. In addition to swelling, the colloidal silica of the fine particles used in the pigment of the inkjet cast gloss paint enters the fine cracks and irregularities of the inkjet cast coat layer to form a smoother inkjet cast gloss layer, and It is presumed that high glossiness and gloss smoothness close to that of a photograph can be obtained by entanglement with the properties of the cast gloss paint itself.

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

According to the present invention, since the inkjet cast gloss layer is formed on the previously formed inkjet cast coat paint layer by the rewetting method, the coating speed during the formation of the inkjet cast gloss layer is 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.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the method for producing an ink jet recording paper of the present invention will be described below. FIG. 1 is a longitudinal sectional side view of an ink jet recording paper manufactured by the manufacturing method of the present invention.

As shown in FIG. 1, the ink jet recording paper manufactured by the manufacturing method of the present invention has an ink jet undercoat layer 2 formed on one surface of a base paper 1 and an ink jet cast coat paint layer 3 and an ink jet recording layer 3. This is a four-layer structure in which the cast glossy layers 4 are sequentially laminated, and the outermost surface thereof conforms to JIS-Z-8741.
The degree of specular gloss is 60 to 80%.

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 in a dry conversion of 5 to 5.
It is formed by coating and drying at about 20 g / m ² . The composition of this ink jet undercoat paint includes a pigment,
An adhesive and a cationizing agent as main components, 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 roughness of the base paper 1 and to smooth the ink-jet cast coat paint layer 3 formed thereon to form the ink-jet undercoat layer 2 on the outermost surface. Improving the smoothness of the cast gloss layer 4, improving the print color density of the inkjet ink, and reducing the variation in air permeability, so that the cast when forming the inkjet cast gloss layer 4 with a cast coating machine. And to improve workability.

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.

As the cationizing agent to be added to the ink jet undercoat layer 2, the following ones are used. 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.

Next, the ink-jet cast coat layer 3 is coated on the ink-jet undercoat layer 2 with 4 to 15 g / dry equivalent of the ink-jet cast coat paint.
m ² approximately, formed by coated dried. The composition of the ink-jet cast coat paint is mainly composed of a pigment, an adhesive, and a cationic emulsion, and a release agent, 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 coating layer 3 is to maintain excellent absorbency of the ink-jet ink, and to provide a high glossiness and a glossy smoothness close to photographs by the ink-jet cast gloss layer 4 formed thereon. This is due to the fact that high print density, excellent fixability of the inkjet ink, and the like are more effectively exhibited. Incidentally, if the ink jet undercoat layer 2 was formed without forming the ink jet cast coat layer 3 and then the ink jet undercoat layer 2 was formed and then subjected to a smoothing treatment and directly coated with the ink jet cast glossy paint, the JIS-Z-8741
The 0-degree specular gloss is only about 35% or less, and cannot achieve the original purpose.

Further, since the ink-jet cast coat layer 3 contains γ-alumina, which is a cationic alumina hydrate, and a cationic emulsion, the ink-jet cast coat layer 3 is formed on the ink-jet cast coat layer 3. Strong adhesion can be obtained by electrical bonding with the anionic colloidal silica used for the cast gloss layer 4.

As a pigment for the ink jet cast coating layer 3, alumina hydrate, fine-particle silica or the like is used. In particular, when forming a cast surface, it is preferable to use a high concentration of the cast paint to be used. From the viewpoint of quality, γ-alumina which is a cationic alumina hydrate is preferably used.

As the adhesive for the ink-jet undercoat layer 3, the same adhesive as that 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.

Examples of the cationic emulsion of the ink-jet cast coat layer 3 include a cationized vinyl acetate emulsion, a urethane emulsion,
Cation-modified synthetic resin emulsions such as acrylic emulsions are preferred.

As a smoothing treatment after the formation of the ink-jet cast coating layer 3, the surface of the coating layer is passed through the nip between rolls by using a usual super calender, gloss calender, thermoplier, or the like. Is achieved by smoothing

Next, the ink jet cast gloss layer 4
After forming the inkjet cast coat paint layer 3,
After the smoothing treatment, the inkjet cast gloss paint is applied and dried in a dry conversion of 0.1 to 5 g / m ² to form a coating. 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 contains gamma-alumina, which is a cationic alumina hydrate contained in the lower ink-jet cast coat layer 3, and a cationic emulsion. , It is possible to obtain strong adhesion 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.

The release agent for the inkjet cast glossy layer 4 is added for the purpose of smoothly removing the coated surface from the chromium-plated cast drum. Fatty acids, fatty acid salts, various wax emulsions and the like are used. They are appropriately selected 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, 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 coating in multiple layers because the coating becomes smoother.

Next, as a second step, the ink-jet cast coat paint is applied on the ink-jet undercoat layer 2 wound up in a roll form in an amount of 4 to 15 g / dry equivalent.
m ² and dried to form an ink-jet cast coat paint layer 3 and wound up in a roll. In addition, a coating machine such as a blade coater, an air knife coater, a reverse coater, a bar coater, a gravure coater, a die coater or the like is used for coating the inkjet cast coat paint as in the first step.

Next, as a third step, the ink-jet cast coat paint layer 3 wound up in a roll shape is separated from the nip between the rolls by using a commonly used super calender, gloss calender, thermoplier, or the like. The surface of the coating layer is smoothed by passing through.

Further, as a fourth step, the above-mentioned ink-jet cast glossy paint, ie, the rewet paint is converted to a dry paint of 0.1 to 0.1% by a rewetting method using a cast coater.
5 g / m ² is applied, and the already formed ink-jet cast coating layer 3 is wetted and swelled, and in the swollen state, is pressed on a chrome-plated cast drum, dried and simultaneously mirror-transferred. Then, the inkjet cast gloss layer 4 is formed and wound into a roll, whereby an inkjet recording paper according to the production method of the present invention is obtained.

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 a method which is also called a direct method, in which a base paper is coated with a cast paint, and the base paper is pressed against a cast drum in a wet state, and the mirror surface of the cast drum is copied simultaneously with drying. It is.

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. <Ink-jet undercoat composition> (Indicated by dry weight) Carplex BS304N (Silica, manufactured by Shionogi & Co., Ltd.) 80 parts by weight Brilliant B15 (light calcium carbonate, manufactured by Shiraishi Industry Co., Ltd.) 20 parts by weight Pateracol IJ50 (urethane emulsion, 17 parts by weight Pateracol D302 (urethane emulsion, manufactured by Dainippon Ink and Chemicals, Inc.) 12 parts by weight PVA217 (PVA, manufactured by Kuraray Co., Ltd.) 10 parts by weight PAS-H-10L (cationizing agent) 7 parts by weight of a diallyldimethylammonium chloride polymer (manufactured by Nitto Boseki Co., Ltd.) By the above mixing, an ink jet undercoat having a coating concentration of 20% was prepared.

Next, as a second step, an air knife coater was applied on the ink jet undercoat layer 2 by using an air knife coater.
The following ink-jet cast coating composition was applied and dried to a dry conversion of 13 g / m ² to form an ink-jet cast coating layer 3 and 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 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.

Next, as a third step, the ink-jet cast coat layer 3 wound up in a roll was smoothed by a super calender under the condition of a linear pressure of 150 kg / cm, and was wound up again in a roll. .

Further, as a fourth step, on the ink-jet cast coat paint layer 3 having been subjected to the smoothing treatment,
With the bar coater of the re-wet cast coating machine,
The following inkjet cast gloss coating composition was coated to a dry conversion of 0.1 g / m ² to wet and swell the already formed inkjet coating coating layer 3, and a chromium-plated cast drum in the swollen state And dried, and at the same time, transfer the mirror surface of the cast drum to form an ink-jet cast gloss layer 4 and wind it, cut it into a predetermined size, and weighed 141.1 g according to the production method of the present invention. / M ² of Example 1 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> On the ink jet undercoat layer 2 obtained in the first step of Example 1, as a second step
The following inkjet cast coat composition was applied by an air knife coater to a dry conversion of 15 g / m ² and dried to form an inkjet cast coat layer 3 and 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.

Next, as a third step, as in Example 1, the ink-jet cast coat layer 3 wound up in a roll shape was applied to a line pressure of 15 with a super calender.
It was smoothed under the condition of 0 kg / cm and wound up again in a roll.

Further, as a fourth step, the following inkjet cast gloss coating composition was converted to a dry equivalent of 5 by a bar coater of a rewetting method cast coating machine on the smoothed inkjet cast coat coating layer 3.
g / m ² , wet and swell the ink-jet coated paint layer 3 already formed, press the swelled state onto a chrome-plated cast drum, dry and simultaneously The ink-jet recording paper of Example 2 having a basis weight of 148 g / m ² according to the production method of the present invention was obtained by transferring and forming the ink-jet cast gloss layer 4, winding it up, and cutting it into a predetermined size. <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 cast coating composition 3 obtained in the second step of Example 1 was subjected to the ink-jet cast gloss coating composition of the fourth step without performing the smoothing treatment of the third step. An ink jet recording paper of Comparative Example 1 was prepared in the same manner as in Example 1 except that an ink-coated gloss layer was formed by coating. (Weight of 141.
1 g / m ² )

<Comparative Example 2> A bar coater of a rewetting method cast coater was used on the smoothed inkjet cast coat paint layer 3 obtained in the third step of Example 1, Inkjet recording paper of Comparative Example 2 in the same manner as in Example 1 except that the coating amount was 0.1 g / m ² in dry conversion using the rewetting liquid used for the production of cast coated paper for printing. And (Basis weight 14
1.1 g / m ² ) <Rewet liquid composition> (Indicated as dry weight part) Sodium hexametaphosphate (commercially available reagent product) 10 weight part Polyethylene emulsion (release agent, commercial product) 10 weight part % Rewet liquid was prepared.

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. △ ・ ・ ・
usually. ×: 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. △ ・ ・ ・
usually. ×: 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. △ ・ ・ ・
usually. ×: 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. △ ・ ・ ・
usually. ×: Inferior. XX: Very poor.

<Results of Test>

[Table 1]

As can be seen from the results of the above test, the quality of Examples 1-2, which are ink jet recording papers produced by the production method of the present invention, was extremely superior in all items as compared with the quality of Comparative Examples 1-2. It turns out to be something.

[0069]

As described above, the ink jet recording paper obtained by the method for producing the ink jet recording paper of the present invention has an ink jet cast coat layer on an ink jet undercoat layer formed on one side of the base paper. After forming and smoothing the surface, the inkjet cast gloss paint is applied by the rewetting method using a cast coater, and the inkjet cast coat paint layer and the inkjet cast gloss paint layer interact with each other. Due to this, the outermost surface has high glossiness, glossy smoothness close to that of photographs, high print density, excellent print water resistance, and retains properties such as excellent fixing properties and absorbency of inkjet ink You can do it.

The ink jet undercoat layer covers the surface of the base paper and is smooth, and the ink jet undercoat layer formed thereon is smoothed.
The smoothness of the outermost inkjet cast gloss layer can be improved. Also, by containing a cationizing agent, the color density of the ink-jet ink is improved, and the formation of the ink-jet undercoat layer reduces the variation in air permeability. Improve the performance.

Next, the ink-jet cast coat layer reliably absorbs the ink-jet ink, and more effectively exerts the properties of the ink-jet cast gloss layer formed thereon without causing rubbing, blocking, stickiness, etc. It is assumed that

Further, the ink-jet cast coat layer contains a cationic alumina hydrate, γ-alumina, and a cationic emulsion,
Strong adhesion is obtained by electrical bonding with the anionic colloidal silica in the inkjet cast glossy paint applied on the inkjet cast coat paint layer.

Further, after forming an ink-jet cast coat paint layer on the ink-jet undercoat layer, the surface of the ink-jet cast gloss paint is subjected to a smoothing treatment prior to coating with an ink-jet cast gloss paint, thereby obtaining an ink-jet. High smoothness can be imparted to the outermost surface of the recording paper.

Further, in addition to the above-mentioned smoothing treatment, when the ink-jet cast gloss paint is applied on the ink-jet cast coat paint layer, that is, when used as a rewet paint, the ink-jet cast gloss paint is already formed. In addition to wetting and swelling the inkjet cast coat paint layer, the fine particles of colloidal silica used in the pigment of the inkjet cast gloss paint enter fine cracks and irregularities in the inkjet cast coat paint layer, resulting in a smoother inkjet cast. It is presumed that the formation of the gloss layer and the properties of the inkjet cast gloss paint itself are intertwined to obtain high gloss and gloss smoothness close to that of a photograph.

Further, since the colloidal silica used in the inkjet cast gloss paint is anionic, as described above, γ, which is a cationic alumina hydrate contained in the lower inkjet cast coat paint layer, is used.
A strong bond can be obtained without the use of an adhesive in the inkjet cast gloss paint by means of an electrical connection with the alumina and the cationic emulsion.

Further, since the ink-jet cast gloss layer was formed on the previously formed ink-jet cast coat layer by the rewetting method, the coating speed during the formation of the ink-jet cast gloss layer was increased, and the cast surface was formed. It is easy and inexpensive to manufacture an ink jet recording paper which can easily obtain stable workability and maintain the above-mentioned various characteristics in terms of quality.

[Brief description of the drawings]

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

[Explanation of symbols]

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

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H086 BA02 BA31 BA33 4L055 AG12 AG17 AG18 AG51 AG64 AG71 AG85 AG94 AG97 AH02 AH37 AH38 AH50 AJ04 BE02 BE09 EA11 EA14 FA12 FA14 FA15 FA19 GA09 GA20

Claims (1)

[Claims] 1. 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 an amount of 5 to 20 g / m ² in dry conversion, and dried. To form an undercoat layer,
On the ink jet undercoat layer, 4 to 15 g / m ^{2 of} an ink-jet cast coat paint containing a cationic γ-alumina as a pigment and a cationic emulsion as an additive is applied in dry conversion and dried to form an ink-jet cast. After forming a coat paint layer and then performing a smoothing treatment, an anionic colloidal silica as a pigment and a release agent as an additive are applied on the inkjet cast coat paint layer by a rewetting method using a cast coater. The used inkjet cast gloss paint (that is, rewet paint) is applied in a dry conversion of 0.1 to 5 g / m ² and dried to form an inkjet cast gloss layer, and the outermost surface is 60 ° specular gloss according to JIS-Z-8741. A method for producing an ink jet recording paper, wherein the degree is 60 to 80%.