JPH08300804A - Method of manufacturing inkjet cast coated paper - Google Patents

Abstract

(57) [Abstract] [Purpose] To efficiently produce inkjet cast coated paper that achieves excellent image quality. [Structure] At least one ink-receiving layer and a gloss-developing layer are laminated on a support in this order from the support side, and once dried, 92 ° C. or more between the heated mirror-drum surface and the nip between the pressure roll. The gloss-developing layer is wetted with the re-wetting liquid under the condition that the wetting time is 25 milliseconds or less, and the gloss-developing layer in the wet state is pressed against the mirror-finished drum surface at a temperature of 95 ° C or higher.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the production of an inkjet cast coated paper which is excellent in surface glossiness, ink absorbency and print density and can efficiently obtain an inkjet cast coated paper which realizes high image quality. Regarding the method.

[0002]

2. Description of the Related Art An ink jet recording system is one in which minute droplets of ink are ejected by various operating principles to be fixed on a recording sheet such as paper to record images, characters, etc., at high speed, low noise, Since it has features such as easy multicoloring, great flexibility in recording patterns, and no need for development and fixing, it has rapidly spread in various applications as a recording method for various figures and color images including Chinese characters. . In particular,
Images formed by the multicolor ink jet method can obtain records that are comparable to those of multicolor printing by the plate making method or printing by the color photographic method. Since it is cheaper than the method using the inkjet recording method, the inkjet recording method has been widely applied to the field of full-color image recording in recent years.

A recording sheet used in this ink jet recording system has a high density of print dots, a bright and vivid image with a color tone is obtained, ink is absorbed quickly, and ink is printed even when print dots overlap each other. It is required that the printed dots do not flow out or bleed, the lateral spread of the print dots is not unnecessarily large, and that the periphery is smooth and does not blur.

On the other hand, as a recording medium having a higher surface gloss than before, cast coated paper having a surface with a high gloss finish is known. Then, a technique in which the technique of the cast coated paper is applied to a recording sheet used in an inkjet recording system is being put to practical use. Specifically, a recording sheet is known in which an ink receiving layer is laminated on a support and the surface of the ink receiving layer is cast.

Direct methods, gelling methods and rewet methods are conceivable as casting methods in the production of ink jet recording sheets using this cast coated paper method. Of these, the direct method is one in which the coating layer applied on the support is still in a wet state, and the coating layer is pressed against the heated mirror-finished drum surface to give a strong gloss finish. Further, the gelling method is a method in which the coating layer applied on the support is brought into contact with a gelling agent bath while the coating layer is still in a wet state, and the coating layer in the gel state is heated to a mirror surface. It has a high gloss finish by pressing it against the drum surface. Further, the rewetting method is a method in which a wet coating layer is once dried and then the coating layer is brought into contact with a rewetting liquid, and then the coating layer is brought into contact with a heating drum for a high gloss finish. is there.

[0006]

However, when the above-mentioned direct method is used, it takes a long time to dry because the coating layer contains a large amount of water, and the water content in the coating layer is This is disadvantageous in terms of production efficiency because the drum surface temperature must be limited to about 80 to 90 ° C. in order to avoid boiling and low speed operation is inevitable.

When the above gelling method is used,
Since the coating layer is relatively strong, the coating layer is not destroyed even when it is pressed against a drum heated to a temperature higher than the boiling point, and therefore the speed can be increased, but it is contained in the coating layer. It is necessary to transfer a large amount of water contained in the base paper layer, which is a support, while passing through the nip between the drum and the pressure roll. Otherwise, the moisture contained in the coating layer explosively boils after passing through the nip, so that the gloss developing layer separates from the drum surface and an inkjet paper having the desired gloss cannot be obtained. Therefore, even when this gelling method is used, the operating speed must be reduced, which is disadvantageous in terms of production efficiency. Moreover, there is a problem that the salt or acid used as the gelling agent remains in the coating layer, and the salt or acid reacts with the dye in the ink to deteriorate the color reproducibility.

On the other hand, the rewetting method does not have the above-mentioned problems of the gelling method, the obtained coating layer is dense and has excellent gloss, and only the surface of the coating layer is rewetted for plasticization. Since it has a merit that it has less moisture evaporated, it has the advantage that the drying rate can be increased and the production efficiency is high, so if the rewet method can be applied to the production of inkjet cast coated paper, It is considered that inkjet cast coated paper can be efficiently manufactured.

However, when the rewet method is applied to the production of ink jet cast coated paper, the ink used in the ink jet recording system uses water as a medium, and therefore the ink itself is not applied to the coating layer. It has a drawback that it acts as a kind of wetting liquid and causes, for example, ink bleeding and, in some cases, destruction of the coating layer, which adversely affects the fixability of the ink.

Therefore, as a result of intensive studies by the present inventors, when the rewet method is used under specific conditions, the ink absorbency is good and the ink fixability is excellent, and the printing density is high and the high image is obtained. The present invention has been achieved by finding that an inkjet paper that realizes quality can be efficiently manufactured.

The present invention has been made under such circumstances, and an object of the present invention is to obtain a high image with a good ink fixing property even when used in an ink jet recording system using an ink containing water as a medium. An object of the present invention is to provide a method for producing an inkjet cast coated paper that can efficiently obtain an inkjet cast coated paper that achieves quality.

[0012]

In order to solve the above-mentioned problems, the first method for producing an ink jet cast coated paper of the present invention is to support at least one ink receiving layer and gloss developing layer on a support. A method for producing an ink jet cast coated paper in which the gloss development layer is wetted after being laminated in this order from the body side, and the gloss development layer in a wet state is pressed against the heated mirror surface drum surface to achieve a strong gloss finish. There is a wetting time of 25 ° C. with the rewetting liquid of 92 ° C. or higher between the nip between the heated mirror surface and the pressure roll.
The gloss-developing layer is moistened under a condition of milliseconds or less, and the gloss-developing layer in a wet state is brought into pressure contact with the specular drum surface at a temperature of 95 ° C. or higher,

The second method for producing an ink jet cast coated paper of the present invention comprises laminating at least one ink receiving layer on a support, and then forming colloidal particles having an average particle diameter of 300 nm or less on the ink receiving layer. Is laminated on the gloss developing layer, the drying layer is once dried, then the gloss developing layer is moistened, and the gloss developing layer in a wet state is heated to a mirror-finished drum surface. And a high gloss finish with a specular gloss of 25% or more specified in JIS Z8741.

The third method for producing an ink jet cast coated paper of the present invention comprises laminating at least one ink receiving layer on a support, and then forming colloidal particles having an average particle diameter of 300 nm or less on the ink receiving layer. Is laminated on the gloss developing layer, the drying layer is once dried, then the gloss developing layer is moistened, and the gloss developing layer in a wet state is heated to a mirror-finished drum surface. A method for producing an ink-jet cast coated paper, which presses against a sheet to give a high gloss finish, and a wetting time of 25 milliseconds or less by a rewetting liquid of 92 ° C. or higher between a nip between a heated mirror surface and a press roll. The gloss developing layer is moistened with, and the gloss developing layer in a wet state is pressed against the specular drum surface at a temperature of 95 ° C. or higher to obtain a specular gloss of 25% according to JIS Z8741. With the above-mentioned strong gloss finish,

If necessary, in the first or third method for producing an ink jet cast coated paper, the rewetting liquid may contain an alkynediol adduct, and if necessary, the alkynediol adduct may be added. 2,4,7,9-Tetramethyl-5-decyne-4,7-
The composition was an ethylene glycol adduct.

In the first method for producing an ink jet cast coated paper of the present invention, first, at least one ink receiving layer is coated on a support. Examples of the support preferably usable in the method of the present invention include LB
Chemical pulp such as KP and NBKP; GP, PGW, RM
Mechanical pulp such as P, TMP, CTMP, CMP, CGP; wood pulp such as waste paper pulp such as DIP; and pigment as main components, binder, sizing agent, fixing agent,
A base paper produced by mixing one or more kinds of various additives such as a yield improver, a cationizing agent and a paper strength enhancer, and using various devices such as a Fourdrinier paper machine, a cylinder paper machine and a twin wire paper machine. , A base paper provided with a size press or anchor coat layer further using starch, polyvinyl alcohol, or the like, art paper, a coated paper, a cast coated paper, etc. provided with a coat layer on the size press or anchor coat layer Coated paper and the like.

In the method of the present invention, these base papers or coated papers may be used as they are, or may be calendered by using a machine calender, TG calender, soft calender or the like to control flattening. You may use it in the state.

The basis weight of the support is usually 40 to 300 g /
It is about m ² , but is not particularly limited. In the method of the present invention, at least 1
The ink receiving layer and the gloss development layer are applied in this order. The ink receiving layer is composed of a coating composition containing a pigment and a binder as main components, and at least one layer is coated on a support.

A white pigment can be preferably used as the pigment. Examples of such white pigments include light calcium carbonate, heavy calcium carbonate, magnesium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin white, aluminum silicate, Diatomaceous earth,
Inorganic pigments such as calcium silicate, magnesium silicate, synthetic amorphous silica, colloidal silica, alumina, colloidal alumina, pseudo-boehmite, aluminum hydroxide, lithopone, zeolite, hydrohaloysite, magnesium hydroxide; styrene plastic pigment, acrylic plastic Pigment, polyethylene, microcapsules, urea resins, melamine resins and other organic pigments.

Examples of the binder include starch derivatives such as oxidized starch, etherified starch and phosphoric acid esterified starch; cellulose derivatives such as carboxymethyl cellulose and hydroxyethyl cellulose; casein, gelatin, soybean protein, polyvinyl alcohol or derivatives thereof; Polyvinyl alcohol with various degrees of saponification or silanol modified products thereof, various derivatives such as carboxylated compounds and cationized compounds; polyvinylpyrrolidone, maleic anhydride resins,
Conjugated diene copolymer latex such as styrene-butadiene copolymer and methyl methacrylate-butadiene copolymer; acrylic polymer latex such as polymer or copolymer of acrylic acid ester and methacrylic acid ester;
Vinyl-based polymer latexes such as ethylene-vinyl acetate copolymers; or functional group-modified polymer latexes with monomers containing functional groups such as carboxy groups of these various polymers; thermosetting synthesis of melamine resins, urea resins, etc. Water-based adhesive such as resin; acrylic such as polymethylmethacrylate; acid ester; polymer or copolymer resin of methacrylic acid ester;
Examples thereof include polyurethane resin, unsaturated polyester resin, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, alkyd resin, and other synthetic resin adhesives.

The mixing ratio of the pigment and the binder in the coating composition constituting the ink receiving layer is 3 to 70 parts by weight, preferably 5 to 100 parts by weight of the binder.
50 parts by weight. When the compounding ratio of the binder is less than 3 parts by weight with respect to 100 parts by weight of the pigment, the coating strength of the ink receiving layer made of such a coating composition may be insufficient. On the other hand, if the mixing ratio exceeds 70 parts by weight,
The ink absorbability of the ink receiving layer made of such a coating composition may decrease.

Further, in the ink receiving layer, for example, a dye fixing agent, a pigment dispersant, a thickener, a fluidity improving agent, a defoaming agent,
Foam suppressor, release agent, foaming agent, penetrant, coloring dye, coloring pigment, fluorescent whitening agent, ultraviolet absorber, antioxidant, preservative,
Various additives such as a mildewproofing agent, a water resistant agent, a wet paper strength enhancer, and a dry paper strength enhancer can be appropriately blended. In particular,
A cation consisting of a secondary amine, a tertiary amine, and a quaternary ammonium salt that forms an insoluble salt with a sulfonic acid group, a carboxyl group, an amino group, etc. in a water-soluble direct dye or a water-soluble acidic dye which is a dye component of an aqueous ink. When a water-soluble dye fixing agent is added, the dye is captured in the ink receiving layer, so that the color is improved and an insoluble salt is formed, which causes the ink to flow out when water is dropped or when moisture is absorbed. Bleeding is suppressed.

The coating amount of the ink receiving layer cannot be generally stated because it varies depending on the required gloss, ink absorbency, kind of support, etc., but it is usually 1 g / m ² or more. Further, the ink receiving layer may be applied by dividing a certain fixed amount of coating twice. When the coating is applied twice in this way, the gloss is improved as compared with the case where the coating amount is applied once.

The coating of the ink receiving layer can be carried out by various machines such as various blade coaters, roll coaters, air knife coaters, bar coaters, rod blade coaters, curtain coaters, short dwell coaters and size presses on machine or off machine. Can be done using. After the ink receiving layer is applied, the ink receiving layer may be flattened by using a calendar device such as a machine calendar, a TG calendar or a soft calendar.

The number of ink receiving layers can be appropriately determined as needed. The gloss-developing layer coated on the ink receiving layer is composed of a coating composition containing a pigment and a binder as main components. Examples of the pigment contained in the gloss developing layer include the same pigments as those contained in the ink receiving layer.

Examples of the binder contained in the gloss-developing layer include starch derivatives such as casein, gelatin, soybean protein, etherified starch, and phosphoric esterified starch;
Natural polymers such as carboxyl derivatives such as carboxyl cellulose and hydroxyethyl cellulose, derivatives thereof, and polyvinyl alcohols having various degrees of saponification or various derivatives thereof such as silanol modified products, carboxyl modified products, cation modified products; polyethylene oxide, polyethylene glycol, polyacrylamide. , Various polyvinylpyrrolidone, melamine resins, urea resins, polyurea polyamide resins, and other water-soluble synthetic polymers and their derivatives such as carboxyl modified products, amide modified products, and cation modified products; and styrene-
Examples thereof include synthetic polymer emulsions of butadiene type, acrylic acid ester and methacrylic acid ester type, ethylene vinyl acetate type, polyurethane type and the like, and modified derivatives thereof such as latex and its carboxyl, amide, and cation modified products based on various amine groups.

The content of the binder in the gloss developing layer is usually 5 to 70 parts by weight, based on 100 parts by weight of the pigment.
It is preferably 5 to 50 parts by weight. When the compounding ratio of the binder to the pigment 100 parts by weight is less than 5 parts by weight,
The coating strength of the gloss development layer may be insufficient. On the other hand, if the above-mentioned mixing ratio exceeds 70 parts by weight, the ink absorbency may be deteriorated and good image quality may not be obtained.

For coating the glossy layer, for example, various blade coaters, roll coaters, bar coaters, rod blade coaters, curtain coaters, short dwell coaters,
Various devices such as a size press can be used.

The coating amount of the gloss-developing layer varies depending on the smoothness and size of the ink-receiving layer, the required smoothness, etc., and therefore it is difficult to determine unconditionally, but usually 2 g /
m ² or more is sufficient. Further, after the gloss-developing layer is cast, curls may be straightened by blowing humidified air or humidified steam onto the back surface of the gloss-developing layer sandwiching the support. Further, machine calender, TG calender, super calender, soft calender You may perform the calendar process using a calendar etc.

In the method of the present invention, the gloss-developing layer is then dried. Drying of the gloss-developing layer may be carried out according to a conventional method using various drying devices such as a hot air dryer, an air foil dryer, an air cap dryer, a cylinder dryer and an infrared dryer.

In the first method of the present invention, the gloss-developing layer is then cast. Specifically, a laminate having at least one ink-receiving layer and a gloss-developing layer applied in this order on a support is passed through a nip between a heated specular drum surface and a pressure contact roll, The gloss developing layer is wetted by bringing the gloss developing layer into contact with the rewetting liquid between the nips, and the gloss developing layer in the wet state is pressed against the heated specular drum surface.

One of the important points in the first method of the present invention is that the temperature of the rewetting liquid which is brought into contact with the gloss developing layer between the heated mirror surface of the drum and the pressure contact roll is 92 ° C.
Or higher, preferably 95 ° C. or higher, and a wetting time of 25
It is set to be not more than millisecond, preferably not more than 20 millisecond, and the temperature of the mirror-finished drum surface which is in pressure contact with the glossy layer in a wet state is set to 95 ° C or higher, preferably 97 ° C or higher.

If the temperature of the re-wetting liquid is lower than 92 ° C., the plasticity of the gloss-developing layer will be insufficient and the adhesion to the mirror-finished drum surface will deteriorate, resulting in pinhole-like spots and uneven gloss. And the like, the ink easily sinks during inkjet recording, and it is difficult to improve the print density. When the wetting time is longer than 25 milliseconds, the wetting becomes excessive and the water-soluble binder is eluted from the gloss developing layer, resulting in uneven binder distribution. As a result, the print density is lowered during ink jet recording, density unevenness, etc. Is more likely to occur and water resistance is also reduced. Further, if the temperature of the mirror surface of the drum is lower than 95 ° C., it takes a long time to dry the gloss developing layer in a wet state, which leads to a decrease in production efficiency, and the gloss of the gloss developing layer is hard to appear, so that the printing dots The shape may be irregular and the image may be rough.

In the first method of the present invention, it is preferable that the rewetting liquid contains an alkynediol adduct. By including the alkynediol adduct in the rewetting liquid, the wetting effect can be promoted without causing ink bleeding.

Examples of the alkynediol adduct having such an action or effect include 2-butyne-1,4.
-Diol adduct, 1-butyne-3,4-diol adduct, 2,5-dimethyl-3-hexyne-2,5-diol adduct, 2,4,7,9-tetramethyl-5-decyne- 4,7-ethylene glycol adduct and the like can be mentioned. Among these, 2,4,7,9-tetramethyl-5-decyne-4,7-ethylene glycol adduct can be particularly preferably used.

When a rewetting liquid containing an alkynediol adduct is used, the content ratio of the alkynediol adduct in the rewetting liquid is usually 0.01 to 5.0% by weight, preferably 0.1 to 5.0% by weight. It is 1.0% by weight. This ratio is 0.0
If it is less than 1% by weight, the alkynediol adduct may not sufficiently promote the wetting effect to be exhibited. on the other hand,
If it exceeds 5.0% by weight, the wetting effect may be excessive and the water resistance of the print may be reduced.

Thus, the ink jet cast coated paper produced by the first method of the present invention is excellent in surface glossiness, ink absorbability and print density.
It realizes high image quality.

Next, a method for manufacturing the second ink jet cast coated paper of the present invention will be described. In the second method for producing an inkjet cast coated paper of the present invention,
First, at least one ink-receiving layer is coated on a support, and then an average particle size of 300 n is formed on the ink-receiving layer.
A gloss-developing layer composed of a coating composition whose main components are colloidal particles of m or less and a binder is applied.

In the second method of the present invention, the support and the ink receiving layer are the same as those in the first method, and therefore their explanations are omitted.

The colloidal particles constituting the gloss developing layer are those which are suspended and dispersed in water and indicate inorganic particles or organic particles having an average particle size of 300 nm or less measured by a dynamic scattering method. Specifically, colloidal silica, boehmite, alumina sol such as pseudo-boehmite, colloidal alumina, cationic alumina oxide or a hydrate thereof,
Further, inorganic particles such as particles obtained by coating the surface of colloidal silica particles with alumina as disclosed in JP-B-47-26959; polystyrene, methyl methacrylate, styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer. , Acrylic acid and methacrylic acid ester copolymers, microcapsules, urea resins, organic particles such as melamine, and the like. These may be used alone or in combination of two or more.

The average particle size of the colloidal particles contained in the gloss developing layer is 300 nm or less, preferably 200 nm or less. When the average particle diameter of the colloidal particles exceeds 300 nm, light is scattered in the gloss developing layer, so that the ink jet cast coated paper having such a gloss developing layer may deteriorate the image quality.

As the binder which is a main component of the gloss developing layer together with the colloidal particles, the same binders as exemplified in the description of the ink receiving layer in the first method can be preferably used. The mixing ratio of the colloidal particles and the binder is 5 to 50 parts by weight, preferably 10 parts by weight of the binder based on 100 parts by weight of the colloidal particles.
~ 40 parts by weight. When the compounding ratio of the binder is less than 5 parts by weight with respect to 100 parts by weight of the colloidal particles, sufficient gloss may not be exhibited. On the other hand, colloid particles 1
If the blending ratio of the binder with respect to 00 parts by weight exceeds 50 parts by weight, the content ratio of the colloidal particles in the coating composition relatively decreases, and the promotion of the wetting effect by the colloidal particles may not be sufficient. Further, the ink absorbability is deteriorated, and the ink remains on the surface of the gloss development layer without drying for a long time after printing, so that the ink is rubbed and the image is stained.

In the second method of the present invention, the gloss-developing layer may contain at least one kind of white pigment together with the colloid particles. In that case, however, the pigment generally has a large particle size and causes opacity. Although it depends on the particle size of the pigment, the weight ratio of the colloidal particles and the pigment is 80/20 or more, preferably 90/10 or more, in the ratio of (colloidal particles) / (white pigment).

Incidentally, in addition to the colloidal particles and the binder, and optionally a white pigment, the gloss-developing layer may contain various additives in the same manner as in the first method.

In the second method of the present invention, the first method is used.
After applying the gloss-developing layer in the same manner as in the above-mentioned method, drying is carried out, and then wetted by contacting with a rewetting liquid in the nip between the heated specular drum surface and the pressure contact roll. The glossy layer in the state is brought into pressure contact with the heated mirror surface drum surface so that the mirror surface glossiness defined by JIS Z8741 is 25% or more. In this way, the ink jet cast coated paper produced by the second method of the present invention has excellent ink absorbency and high transparency of the gloss-developing layer, so that the print density is improved and excellent image quality is obtained. To be realized.

Next, the third method of the present invention will be described. In the third method of the present invention, in the same manner as in the second method, at least one ink-receiving layer and a gloss-developing layer containing colloid particles having an average particle diameter of 300 nm or less as a main component are formed on a support. After being applied to form a laminated body, the laminated body is passed through a nip between the heated mirror surface of the drum and the pressure contact roll, and the gloss developing layer is heated to a temperature of 92 between the nip.
The re-wetting liquid having a temperature of 95 ° C or higher, preferably 95 ° C or higher is contacted with the rewetting liquid for 25 milliseconds or less, preferably 20 milliseconds or less, and the gloss developing layer in a wet state is set to a temperature of 95 ° C or higher, preferably 97 ° C or higher. A strong gloss finish is performed by pressing it against the mirror surface.

If the temperature of the rewetting liquid is lower than 92 ° C., the plasticity of the gloss developing layer is insufficient and the adhesion to the mirror-finished drum surface is lowered, resulting in pinhole-like spots and uneven gloss. And the like, the ink easily sinks during inkjet recording, and it is difficult to improve the print density. When the wetting time is longer than 25 milliseconds, the wetting becomes excessive and the water-soluble binder is eluted from the gloss developing layer, resulting in uneven binder distribution. As a result, the print density is lowered during ink jet recording, density unevenness, Bleeding is likely to occur. Further, if the temperature of the mirror surface of the drum is lower than 95 ° C., it takes a long time to dry the gloss developing layer in a wet state, which leads to a decrease in production efficiency, and the gloss of the gloss developing layer is hard to appear, so that the printing dots The shape may be irregular and the image may be rough.

Further, in the third method of the present invention, it is preferable to add the alkynediol adduct to the rewetting liquid in the same manner as in the first method.
It is preferred to include the 4,7,9-tetramethyl-5-decyne-4,7-ethylene glycol adduct in the rewetting liquid. The content ratio of the alkynediol adduct in the rewetting liquid is the same as in the first method. Thus, the inkjet cast coated paper produced by the third method of the present invention is excellent in surface gloss, ink absorbency and print density, and realizes high image quality.

[0049]

EXAMPLES Examples of the present invention will now be described to more specifically describe the present invention. Unless otherwise specified, "parts" and "%" in the examples and comparative examples represent absolute dry weight parts and absolute dry weight%, respectively. In addition, the particle diameters shown in Examples and Comparative Examples are average particle diameters obtained by the dynamic scattering method.

Example 1 Preparation of Support 80 parts LBKP (freezing degree 400 mlcsf) and NBKP
Pigment 25 having a ratio of light calcium carbonate, heavy calcium carbonate and talc of 10/10/10 to 100 parts of wood pulp consisting of 20 parts (freeness 400 mlcsf)
Parts, commercially available alkyl ketene dimer 0.10 parts, commercially available cationic (meth) acrylamide 0.03 parts, commercially available cationized starch 0.80 parts, and sulfuric acid band 0.40 parts as a mixture to prepare a fourdrinier paper machine. It was used to make a support having a basis weight of 90 g / m ² .

Coating of Ink Receiving Layer On the surface of the above-mentioned support, a coating composition having the following composition was prepared at a solid content concentration of 16%, and this coating solution was dried with an air knife coater to give a coating amount of 12 g / m 2. ^It was coated and dried so that it would be ² . -Ink receiving layer coating composition-Synthetic amorphous silica (Mizukasil P75D: manufactured by Mizusawa Chemical Co., Ltd.) ... 100 parts Polyvinyl alcohol (PVA117: manufactured by Kuraray Co., Ltd.) ... 25 parts Colloidal silica (Snowtex-O: NISSAN CHEMICAL INDUSTRIES, LTD .... 30 parts Cationized dye fixing agent (Polyfix 601: Showa Polymer Co., Ltd.) ... 25 parts

Coating of gloss-developing layer A coating composition having the following composition was prepared on the surface of the above-mentioned ink receiving layer at a solid content concentration of 22%, and the coating solution was dried by a roll coater to give a coating amount of 6 g / It was coated and dried so as to be m ² . -Glossy layer coating composition- Colloidal particles (average particle diameter 65 nm, Snowtex XL: Nissan Chemical Industries, Ltd.) ... 100 parts Styrene butadiene latex (0693: Nippon Synthetic Rubber Co., Ltd.) ... 30 parts Oleine Potassium acidate 2 parts

The laminated body obtained as described above was used under the following conditions using an apparatus having a pressure roll having a diameter of 300 mm and a mirror surface drum having a diameter of 1250 mm, and further having a nozzle arranged on the nip. Rewet casting was performed to obtain an inkjet cast coated paper. -Rewet casting conditions- Rewetting liquid used: hot water Rewetting liquid temperature: 95 ° C Mirror surface temperature: 95 ° C Press nip pressure: 150 kg / cm ² Wetting time: 20 ms

The print water resistance, specular gloss, ink absorbency and print density of this ink jet cast coated paper were evaluated as follows. The results are shown in Table 1.
Shown in <Printing Water Resistance> A 100% solid printing portion of black ink was immersed in running water for 5 minutes, air-dried, and the rate of change in optical density was measured. The data is expressed in%. If the rate of change of the optical density is 115% or less, it is practical. An inkjet recording device (BJC-820J: manufactured by Canon Inc.) is used to form a printed image, and an optical reflection density measuring device (Macbeth RD-918 type: KOLLMORGEN CORPORA) is used to measure the optical density.
TION) was used. <Specular glossiness> The specular glossiness of the surface of the gloss-developing layer that has been cast is measured by the Nippon Denshoku Industries Co., Ltd. variable angle gloss meter (VGS-
1001DP) and was measured according to JIS Z8741. <Ink Absorption> Inkjet recording device (BJC-8
20J: manufactured by Canon Inc.) is used to print a heavy-colored rectangular pattern with cyan ink and magenta ink, and the boundary between this pattern and the blank sheet part is printed according to the following criteria.
The evaluation was performed visually. A: No distortion is observed at the boundary. B: A slight distortion is seen at the boundary. C: Distortion is seen in all of the boundaries. <Print density> A solid pattern is printed with black ink using the inkjet recording device described above, and the printed area is printed with KOLL.
MORGEN CORPORATION optical reflection density measuring device (Macbeth R
D-918 type). The print density is 1.
If it is 25 or more, an image with color is obtained.

[0055]

[Table 1]

Example 2 Ink jet cast coated paper was prepared in the same manner as in Example 1 except that the rewet cast conditions were as follows in Example 1, and the ink jet cast coated paper obtained was printed. Water resistance, specular gloss, ink absorbency and print density were evaluated. The results are shown in Table 1. -Rewet casting conditions-Rewetting liquid used: hot water Rewetting liquid temperature: 92 ° C Mirror surface temperature: 95 ° C Press nip pressure: 150 kg / cm ² Wetting time: 25 ms

Example 3 Inkjet cast coated paper was prepared in the same manner as in Example 1 except that the glossy layer coating composition in Example 1 was changed to the following composition. The print water resistance, specular gloss, ink absorbency and print density of the coated paper were evaluated. The results are shown in Table 1. -Glossy layer coating composition- Colloidal particles (average particle size 200 nm, polystyrene emulsion L8999: manufactured by Asahi Kasei Kogyo Co., Ltd.) ... 100 parts Cationic acrylic latex (Boncoat SFC55: manufactured by Dainippon Ink and Chemicals, Inc.) ... 25 Part Potassium oleate ... 2 parts

Example 4 Inkjet cast coated paper was prepared in the same manner as in Example 1 except that the gloss-developing layer coating composition was changed to the following composition in Example 1, and the ink jet cast was obtained. The print water resistance, specular gloss, ink absorbency and print density of the coated paper were evaluated. The results are shown in Table 1. -Glossy layer coating composition- Colloidal particles (average particle size 300 nm, PTS3: Nissan Chemical Industries, Ltd.) ... 100 parts Styrene butadiene latex (0693: Nippon Synthetic Rubber Co., Ltd.) ... 20 parts Potassium oleate … Part 2

Example 5 Inkjet cast coated paper was prepared in the same manner as in Example 1 except that the composition for coating the ink-receiving layer in Example 1 was changed to the following composition. Printing water resistance of coated paper, specular gloss,
The ink absorbency and print density were evaluated. The results are shown in Table 1. -Ink Receiving Layer Coating Composition-Synthetic Amorphous Silica (Fineseal X37B: Tokuyama Soda Co., Ltd.) ... 100 parts Polyvinyl alcohol (PVA117: Kuraray Co., Ltd.) ... 20 parts Colloidal silica (Snowtex-O) : Nissan Chemical Industries, Ltd.) 10 parts Cationized dye fixing agent (Polyfix 601: Showa Polymer Co., Ltd.) 25 parts

Example 6 Inkjet cast coated paper was prepared in the same manner as in Example 1 except that the glossy layer coating composition in Example 1 was changed to the following composition. The print water resistance, specular gloss, ink absorbency and print density of the coated paper were evaluated. The results are shown in Table 1. -Glossy layer coating composition- Colloidal particles (average particle size 500 nm, PTS5: Nissan Chemical Industries, Ltd.) ... 100 parts Styrene butadiene latex (0693: Nippon Synthetic Rubber Co., Ltd.) ... 20 parts Potassium oleate … Part 2

Example 7 In Example 1, the rewetting liquid used in the rewet cast coat was changed from warm water to Surfynol 465 (manufactured by Nisshin Chemical Co., Ltd.) rewetting liquid (concentration 0.1%). Inkjet cast coated paper was prepared in the same manner as in Example 1, and the ink jet cast coated paper obtained was evaluated for print water resistance, specular gloss, ink absorbency and print density. The results are shown in Table 1.

Example 8 Inkjet cast coat was carried out in the same manner as in Example 1 except that the concentration of the rewetting liquid used in the rewet cast coat was changed from 0.1% to 1.0%. Paper was prepared, and the ink jet cast coated paper obtained was evaluated for print water resistance, specular gloss, ink absorbency, and print density. The results are shown in Table 1.

Example 9 In Example 7, the rewetting liquid used in the rewet cast coat was changed from Surfynol 465 (manufactured by Nisshin Chemical Co., Ltd.) (concentration 0.1%) to Surfynol 485.
(Nisshin Chemical Co., Ltd.) (concentration 0.1%), except that the ink jet cast coated paper was prepared in the same manner as in Example 7, and the ink jet cast coated paper obtained was printed with water resistance, The specular gloss, ink absorbency and print density were evaluated. The results are shown in Table 1.

Example 10 Inkjet cast coated paper in the same manner as in Example 1 except that the rewetting liquid used in rewet cast coating was changed from warm water to polyethylene glycol commercial product (molecular weight 500) in Example 1 above. Create
The ink jet cast coated paper thus obtained was evaluated for print water resistance, specular gloss, ink absorbency and print density. The results are shown in Table 1.

Comparative Example 1 Inkjet cast-coated paper was prepared in the same manner as in Example 1 except that the rewet cast conditions were set as follows, and the ink-jet cast-coated paper obtained was printed. Water resistance, specular gloss, ink absorbency and print density were evaluated. The results are shown in Table 1. -Rewet casting conditions-Rewetting liquid used: hot water Rewetting liquid temperature: 80 ° C Mirror surface temperature: 95 ° C Press nip pressure: 150 kg / cm ² Wetting time: 20 ms

Comparative Example 2 Inkjet cast coated paper was prepared in the same manner as in Example 1 except that the rewet cast conditions were set as follows, and the ink jet cast coated paper obtained was printed. Water resistance, specular gloss, ink absorbency and print density were evaluated. The results are shown in Table 1. -Rewet casting conditions- Rewetting liquid used: hot water Rewetting liquid temperature: 92 ° C Mirror surface temperature: 95 ° C Press nip pressure: 150 kg / cm ² Wetting time: 40 ms

Comparative Example 3 Inkjet cast coated paper was prepared in the same manner as in Example 1 except that the rewet cast conditions were set as follows, and the ink jet cast coated paper obtained was printed. Water resistance, specular gloss, ink absorbency and print density were evaluated. The results are shown in Table 1. -Rewet casting conditions-Rewetting liquid used: hot water Rewetting liquid temperature: 92 ° C Mirror surface temperature: 85 ° C Press nip pressure: 150 kg / cm ² Wetting time: 25 ms

-Examination of Results- As is apparent from Table 1, the ink jet cast coated papers of Examples 1 to 10 obtained by the method of the present invention are the ink jet cast coated papers of Comparative Examples 1 to 3. It can be seen that the balance among print water resistance, specular glossiness, ink absorbency, and print density is maintained at a high level compared to. From this, it was confirmed that according to the method of the present invention, an inkjet cast coated paper having high image quality can be efficiently obtained by applying the rewet method advantageous in terms of production efficiency.

[0069]

As is clear from the above, the method for producing an ink jet cast coated paper of the present invention is such that the gloss developing layer coated on the ink receiving layer is once dried and then the gloss developing layer is formed. By contacting with a high temperature re-wetting liquid, the glossy layer is momentarily wetted to achieve a high gloss finish, so that the range where the wetting effect by the rewetting bath is obtained is limited to the surface of the glossy layer. As a result, the wetting effect of the rewetting bath is prevented from adversely affecting the ink receiving layer. Therefore, according to the method of the present invention, it is possible to efficiently manufacture an inkjet paper having good print water resistance and ink absorbability, excellent ink fixability, high print density, and high image quality. it can.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kunio Suzuki 34-2 Marunouchi, Chiyoda-ku, Tokyo Inside Mitsubishi Paper Mills Co., Ltd.

Claims (5)

[Claims] 1. A support, on which at least one ink-receiving layer and a gloss developing layer are laminated in this order from the support side,
A method for producing an ink jet cast coated paper, which comprises a step of moistening the gloss developing layer once and then bringing the wet gloss developing layer into pressure contact with a heated mirror surface drum surface to obtain a strong gloss finish. Wetting time 2 with a rewetting liquid of 92 ° C or higher between the nip between the drum surface and the pressure roll.
A method for producing an ink jet cast coated paper, which comprises moistening the gloss developing layer under a condition of 5 milliseconds or less, and pressing the wet gloss developing layer against the specular drum surface at a temperature of 95 ° C or higher. 2. A gloss expression comprising a coating composition comprising, as a main component, at least one ink-receiving layer laminated on a support, and then the ink-receiving layer comprising colloidal particles having an average particle diameter of 300 nm or less as a main component. After the layers are laminated and the gloss developing layer is once dried, the gloss developing layer is moistened, and the gloss developing layer in a wet state is pressed against the heated mirror-finished drum surface according to JIS.
A method for producing an ink jet cast coated paper, characterized by performing a strong gloss finish with a specular gloss of 25% or more specified in Z8741. 3. A coating composition comprising at least one ink receiving layer laminated on a support, and then comprising, on the ink receiving layer, a colloidal particle having an average particle diameter of 300 nm or less and a binder as main components. After laminating the gloss developing layer, drying the gloss developing layer once, and then wetting the gloss developing layer,
A method for producing an inkjet cast coated paper in which a glossy layer in a wet state is pressed against a heated mirror surface drum surface to achieve a strong gloss finish, wherein a temperature of 92 ° C. is maintained between a nip between the heated mirror surface drum surface and a pressure contact roll. The re-wetting liquid is used to moisten the gloss developing layer under the condition that the wetting time is 25 milliseconds or less, and the gloss developing layer in a wet state is pressed against the mirror-drum surface having a temperature of 95 ° C. or higher to be prescribed in JIS Z8741. A method for producing an ink jet cast coated paper, characterized by performing a strong gloss finish with a specular gloss of 25% or more. 4. The method for producing an inkjet cast coated paper according to claim 1, wherein the rewetting liquid contains an alkynediol adduct. 5. The alkynediol adduct is 2,4.
The method for producing an inkjet cast coated paper according to claim 4, which is an adduct of 7,9-tetramethyl-5-decyne-4,7-ethylene glycol.